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  • 2051.
    Ahlvik Doverhem, Rebecka
    Stockholm University, Faculty of Law, Department of Law.
    Förhållandet mellan förskott på arv och laglott: en belysning av rättsläget och dess tillämpningsproblem2016Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
  • 2052. Ahlvik, P
    et al.
    Karlsson, Hans
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Åsman, P
    Exhaust emissions from flexi-fuel light-duty passenger cars fuelled by petrol (E5) and bioethanol (E70, E85) tested at ambient temperatures of +22°C and -7°C: Part 1:Regulated and particulate emissions.2008In: Proceedings of the17:th International Symposium on Alcohol Fuels, 2008Conference paper (Other academic)
  • 2053.
    Ahlzén, Björn
    Stockholm University, Faculty of Social Sciences, Department of Sociology.
    Att bryta mot samhällsnormer: En kvantitativ studie om hög alkoholkonsumtion och narkotikabruk2011Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Synen på hög alkoholkonsumtion respektive narkotikabruk skiljer sig mellan olika samhällen, och i Sverige har vi en tradition av att problematisera dessa beteenden i högre grad än i många andra länder. Dessutom ses narkotikabruk som en mer klandervärd handling än hög alkoholkonsumtion. Med dessa socialt konstruerade skillnader i åtanke fokuserar uppsatsen på vad om ligger bakom dessa beteenden och om liknande faktorer kan förklara dem. Uppsatsens syfte är med andra ord att undersöka huruvida liknande bakgrundsvariabler kan förklara hög alkoholkonsumtion och narkotikabruk bland individer i Sverige. För att förstå varför olika sociala regler och normer råder i olika samhällen används Howard Beckers klassiska stämplingsteori. Tidigare forskning visar att i synnerhet kön och ålder är viktiga variabler för att förklara skillnader i alkoholkonsumtion och narkotikabruk, men även inkomst och familjekonstellation tycks spela en roll. För narkotikabruk verkar även sysselsättning och möjligen också utbildning ha betydelse. Studien är kvantitativ och bygger på ett datamaterial bestående av 5 469 respondenter. Analyserna genomfördes med logistisk regressionsanalys. Resultaten visade att det endast finns signifikanta samband mellan hög alkoholkonsumtion och variablerna kön och ålder, då män och yngre i högre grad riskerar att vara högkonsumenter av alkohol. För narkotikabruk var de signifikanta sambanden fler, förutom kön och ålder hade även sysselsättning, inkomst och huruvida man bor med en partner eller inte en signifikant effekt för förklaringen av vilka som brukar narkotika. Starkast var dock, även här, sambanden för kön och ålder som hade samma riktning som för hög alkoholkonsumtion. Detta skulle kunna tyda på att män och yngre personer inte fördöms lika hårt som övriga grupper när de högkonsumerar alkohol respektive brukar narkotika. Då narkotikabruk visade sig vara mycket ovanligt skulle studien gynnas av ett större datamaterial då säkrare slutsatser skulle kunna dras.

  • 2054.
    Ahlzén, Maja-Stina
    Stockholm University, Faculty of Social Sciences, Department of Social Work.
    Vägen till hemlöshet: en studie av nio livshistorier2005Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Syftet med studien är att öka förståelsen för den process som leder till hemlöshet. Utifrån intervjuer med nio personer belyses de hemlöshetsgenererande processer som för var och en av dem lett till att de förlorat sin bostad och inte kunnat få någon ny.

    Intervjuerna har analyserats med hjälp av fattigdomsspiralen. Analysen visar hur de intervjuades resurser successivt har utarmats när de passerat genom olika stadier av kriser och svårigheter. Successivt har de förlorat makten över sina liv och för några av dem har detta lett till permanent fattigdom och utslagning. Genom att använda ett krisperspektiv kan utslagningsprocessen göras tydlig.

    Studien visar också hur socialtjänsten för flera av de intervjuade medverkat i utslagningsprocessen. Samtliga intervjupersoner har varit med om svåra trauman som de inte fått möjlighet att bearbeta. I mötet med socialtjänsten har deras trauman inte uppmärksammats och insatserna har i stor utsträckning inte varit individuellt anpassade.

    Även ett historiskt perspektiv kan tydliggöra utslagningsprocessen. Litteraturen visar hur attityderna gentemot fattiga och hemlösa har växlat genom historien.Till stora delar kan dagens sociallagstiftning härledas till medeltiden. Samtliga intervjupersoner har mött regler och förordningar vars underliggande attityder har sina rötter långt tillbaka i tiden.

    En viktig slutsats av studien är att socialtjänsten och andra berörda myndigheter bör sträva efter att i mycket större utsträckning än i dag ge varje hemlös ett individuellt bemötande. Åtgärder bör anpassas efter den hemlöses uppfattning om sina behov och inte efter myndighetens åtgärdsrepertoar.

  • 2055.
    Ahlén, Anton
    Stockholm University, Faculty of Social Sciences, Department of Political Science.
    Unconditional Conditions: A Study of How Civic Integration Policies Affect Migration Flows in Europe2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In the last decade, there has been a diffusion of civic integration policies in Europe, which

    requires immigrants by certain category of entry to accomplish integration tests for

    acquisition of residence. Despite a flurry of literature based on civic integration policies,

    attention drawn to the implication of these policies has been quite rare. This thesis examines

    how civic integration strategies associate with immigration, and tests if civic integration

    policies are connected to variations of immigration by certain category of entry. I argue in

    this thesis that the conditional factor in civic integration policies creates a barrier for affected

    migrants and their possibility to gain long term residence in the host country. Based on

    theories of immigrant integration that relate civic integration to the backlash against

    multiculturalism in Europe, the thesis emphasize a reasoning in which the push for internal

    inclusion seems to be associated with excluding implications. The result presented here

    shows that there are connections between the extension of civic integration policies and

    reduced family and labour immigration between 2004 and 2011. The connection between the

    variables can however not be discerned from other integration requirements. The main

    concern is the lack of harmonized data, which obstructs the possibility to test for causality

    and to draw generalizing conclusions. However, the thesis reveals noteworthy correlations

    between the concepts, which contribute to the research field by connecting civic integration

    to immigration and by showing what implications civic integration policies may result in.

  • 2056.
    Ahlén, Barbro
    et al.
    Stockholm University, Faculty of Social Sciences, Department of Education.
    Ekström, Anna
    Stockholm University, Faculty of Social Sciences, Department of Education.
    Samtalets dilemma: Vägledning som instrument vid sjukfrånvaro2009Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Counselling is one of the most commonly utilized tools in the work place. The purpose of this paper is to explore how four employers utilize early counselling sessions related to absences due to illness. A qualitative research method has been used and four human resource managers have been interviewed. The research questions have been divided into three categories: the counselling structure, the counselling model and the counselling dilemmas. The interviews have been transcribed and processed through these three categories. The results show that most employers are positive regarding conducting initial counselling sessions related to work absences. The experience of the session can vary depending on one’s role in the counselling session. Counselling sessions related to short term work absences are impacted by labour legislation, changes in the workplace, the company culture, and the amount of power held by the person who conducts the counselling session. One of the conclusions of this study is that it is difficult to combine initial counselling sessions regarding work absences with career counselling 

  • 2057.
    Ahlén, Emil
    et al.
    Stockholm University, Faculty of Social Sciences, Department of Social Work.
    Lundberg, Linn
    Stockholm University, Faculty of Social Sciences, Department of Social Work.
    Konstruktioner av en sexköpare: en diskursteoretisk analys av offentliga dokument2017Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of this study is to present dominant discourses of sex buyers in public documents published before and after the implementation of the Swedish sex buyer law; making the purchase but not the sale of sexual services illegal. The purpose is further to examine what consequences these discourses might have on social work with sex buyers. We also aim to illustrate how language, gender, sexuality and power can be understood in the reading of the empirical material stretching from 1981 to 2016. With a discourse theoretical approach drawn from Laclau and Mouffe (2008 [1985]), five prominent discourses are identified; the average man, the homosexual man, the woman as a sex buyer, the man with the problematic sexuality and the sex buyer in need of help. The main findings are that processes of conflict among the discourses outlines a social problem where discourses that don’t include the heterosexual man as a sex buyer are subdued. Gender and sexuality in general and male heterosexual sexuality in particular is performed. As demands on a stricter legislation is propositioned we identified a linguistic offset; from descriptive graphic characteristics of the sex buyer to a depersonalization focusing on the action rather than the actor. 

  • 2058.
    Ahlén, Niklas
    Stockholm University.
    Carbothermal synthesis of transition metal carbide and carbonitride whiskers via a Vapour-Liquid-Solid (VLS) growth mechanism1999Doctoral thesis, monograph (Other academic)
    Abstract [en]

    A route for the synthesis of TiC, TiCyN1-y, TaxTi1-xC and TaxTi1-xCyN1-y whiskers via a carbothermal Vapour-Liquid-Solid (VLS) growth mechanism, yielding 70-90 vol.% whiskers, has been established. The whiskers were uniform in diameter (0.3-0.6mm), and had a length of about 10-30mm. The starting materials consisted of TiO2 and/or Ta2O5, C, a catalyst metal (Ni or Fe) and NaCl. Carbon was added to reduce the oxides, and NaCl to provide chlorine in the formation of TiClx(g) and TaOxCly(g) species. The overall chemical reaction is a straightforward carbothermal reduction process. The optimum synthesis temperature was found to be 1250°C for TiCyN1-y, TaxTi1-xC and TaxTi1-xCyN1-y whisker, and 1400°C for TiC. The growth direction of the whiskers was found to be <100> for TaC and TaxTi1-xC and either <100> or <111> for TiC. Nitridation of TiC whiskers yielded TiCyN1-y whiskers with morphology and chemical composition different from those obtained by the carbothermal VLS growth mechanism. From oxidation studies it was found that TiC had the lowest oxidation resistance (onset temperature Ton=390°C) and that TaC had the highest (Ton=550°C). The oxidation onset temperature was found to increase with increasing x-value for both TaxTi1-xC and TaxTi1-xCyN1-y whiskers. Microscopy studies (SEM and TEM) showed that whiskers with a native diameter exceeding 0.3 mm split into two halves along their length when oxidised. It was found that the TiO2 particle size of oxidised TaxTi1-xC whiskers are markedly smaller than that obtained from oxidation of TiC whiskers, whereas the Ta2O5 particle size was the same as that observed for oxidised TaC whiskers.

  • 2059.
    Ahlénius, Emily
    Stockholm University, Faculty of Social Sciences, Department of Criminology.
    A Qualitative Analysis of the JudicialAspects of Child-Sex Tourism inThailand2010Independent thesis Basic level (degree of Bachelor), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    Every year Thailand is invaded by tourists seeking the sun and white beautiful beaches. Most of them come for the inexpensive travel and lodging, good food and kind inviting people. For some of them the purpose of visit is somewhat different: every year there are people travelling to Thailand with the purpose to sexually exploit children. The world wide globalisation has contributed to a massive growth in tourism which has brought an economical growth to the country. This in turn has had some negative effects, where the poor rural areas are largely affected by inequality and the dream of a better lifestyle. Economical disadvantage, lack of education and the absence of capable guardians affect children’s vulnerability and make them an easy target for child-sex tourism. I argue that potential child-sex tourists travel to Thailand due to a perception of the prevalence of easy targets affected by people in a society that is not always aware of what is happening around them as well as due to a common perception that Thailand has a weak legal system. Based on this assumption and with the theoretical basis of routine activity and rational choice I research if there is a reason to believe that the legal system is corrupt. I believe that a combination of the three elements provided routine activity as well as analysing a phenomenon through rational choice can open up to answers of why perpetrators chose Thailand as their child-sex vacation hot-spot. To address the aim of my study I conducted six semi-structured interviews with people working in Bangkok, Thailand. From these interviews I first explain the process leading to the prosecution of Swedish child-sex tourists in Thailand and, second, uncover and examine potential difficulties in this process. In the result of this study a few of the answers differ substantially from previous studies as well as some of the interviewees sharing controversial opinions. The results of the conducted interviews show three identifiable weaknesses that play a large part in the problems of the judicial process. These three are: education, bail and cooperation between authorities.

  • 2060. Ahmad, Anees
    et al.
    Scarassati, Paulo
    Jalalian, Nazli
    Stockholm University, Faculty of Science, Department of Organic Chemistry. Universidade de São Paulo, Brazil.
    Olofsson, Berit
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Silva, Luiz F., Jr.
    Oxidative rearrangement of alkenes using in situ generated hypervalent iodine(III)2013In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 54, no 43, p. 5818-5820Article in journal (Refereed)
    Abstract [en]

    A novel protocol for the oxidative rearrangement of alkenes using in situ generated hypervalent iodine(III) was developed. This approach uses inexpensive, readily available, and stable chemicals (PhI, mCPBA, and TsOH) giving rearrangement products in yields comparable to those obtained using the more expensive commercially available [hydroxy(tosyloxy)iodo]benzene [HTIB or Koser's reagent]. Additionally, an alternative protocol for the synthesis of 1-methyl-2-tetralone through the one-step epoxidation/rearrangement of 4-methyl-1,2-dihydronaphthalene using mCPBA and TsOH was developed.

  • 2061.
    Ahmad, Farhan
    Stockholm University, Faculty of Social Sciences, School of Business.
    Knowledge Transfer: Mechanism Selection Criteria2009Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
    Abstract [en]

    Knowledge transfer is one of the dominant topics in the organizational research today. This study criticizes the focus of the researchers to use the nature of knowledge as criteria to select a knowledge transfer mechanism. Consideration of this only criterion has led us to ignore the other relevant and important factors which could be very useful for selecting an appropriate knowledge transfer mechanism. On the basis of the fact that there is a high failure rate of the knowledge transfer mechanisms in the organizations, author tried to explore the effective factors in the selection of knowledge transfer mechanism because researchers believe that selection is the area which needs consideration for successful knowledge transfer. For this purpose two mechanisms i.e. expatriation and training were studied in three organizations. Interviews were used to find the primary information in the study. Findings imply that four factors geographic location, preconception of success, image development and size and age of the organization has dominant effect on the selection of knowledge transfer mechanism. This study tries to shift the focus of the research from consideration of more theoretical aspects like nature of knowledge to more practical ones like found in the study.

  • 2062.
    Ahmad, Farhan
    Stockholm University, Faculty of Social Sciences, Department of Sociology.
    Male immigrants’ fertility in Spain2011Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Declining fertility in developed countries along with rising number of immigrants and different fertility behavior exhibited by the immigrants make the immigrants’ fertility an interesting topic in field of demography. However most of the studies on immigrants’ fertility consider the female immigrants as their subject on the assumption that they represent the immigrants’ fertility. This study took another perspective and tries to study male immigrants’ fertility. Spanish Immigrants’ Survey 2007 was used to see how the different migration related factors affect the male immigrants’ fertility. Poisson regression was applied on a sample of 3797 childless males who are 16 or older. This study found tentative support to selection hypothesis but no clear support to adaptation hypothesis on male fertility behaviors. There exist differences in the fertility between male immigrants from different regions. Effect of education, number of parent’s siblings and mother language on male immigrants’ fertility was also analyzed.

  • 2063. Ahmad, Fouad
    et al.
    Ibrahim, Maha
    El-Esnawy, N
    Fors, Uno
    Stockholm University, Faculty of Social Sciences, Department of Computer and Systems Sciences.
    An e-Learning Faculty Development Course with Formative Assessment2010In: 16th Annual Sloan Consortium International Conference on Online Learning, 2010Conference paper (Other academic)
    Abstract [en]

    An e-Learning faculty development course has been developed and taught in Egypt for the past five years. The course adopts Formative Assessment (FA) techniques to enhance participants' learning. The additional FA effort for collecting and analyzing data as well as adjusting teaching is worth investing to accommodate gaps in learning.

  • 2064. Ahmad, Nawaz
    et al.
    Wörman, Anders
    Sanchez-Vila, Xavier
    Jarsjö, Jerker
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Bottacin-Busolin, Andrea
    Hellevang, Helge
    Injection of CO2-saturated brine in geological reservoir: A way to enhanced storage safety2016In: International Journal of Greenhouse Gas Control, ISSN 1750-5836, E-ISSN 1878-0148, Vol. 54, p. 129-144Article in journal (Refereed)
    Abstract [en]

    Injection of free-phase supercritical CO2 into deep geological reservoirs is associated with risk of considerable return flows towards the land surface due to the buoyancy of CO2, which is lighter than the resident brine in the reservoir. Such upward movements can be avoided if CO2 is injected in the dissolved phase (CO2aq). In this work, injection of CO2-saturated brine in a subsurface carbonate reservoir was modelled. Physical and geochemical interactions of injected low-pH CO2-saturated brine with the carbonate minerals (calcite, dolomite and siderite) were investigated in the reactive transport modelling. CO2-saturated brine, being low in pH, showed high reactivity with the reservoir minerals, resulting in a significant mineral dissolution and CO2 conversion in reactions. Over the injection period of 10yr, up to 16% of the injected CO2 was found consumed in geochemical reactions. Sorption included in the transport analysis resulted in additional quantities of CO2 mass stored. However, for the considered carbonate minerals, the consumption of injected CO2aq was found mainly in the form of ionic trapping.

  • 2065.
    Ahmad, Nina Sna
    Stockholm University, Faculty of Law, Department of Law.
    Privatkopieringsersättning för molntjänster: exemplarframställning av upphovsrättskyddade verk i molnbaserade lagringstjänster och fråga om privatkopieringsersättning2015Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
  • 2066. Ahmad, Shabbir
    et al.
    Thulasingam, Madhuranayaki
    Palombo, Isolde
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Daley, Daniel O.
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Johnson, Kenneth A.
    Morgenstern, Ralf
    Haeggström, Jesper Z.
    Rinaldo-Matthis, Agnes
    Trimeric microsomal glutathione transferase 2 displays one third of the sites reactivity2015In: Biochimica et Biophysica Acta - Proteins and Proteomics, ISSN 1570-9639, E-ISSN 1878-1454, Vol. 1854, no 10, p. 1365-1371Article in journal (Refereed)
    Abstract [en]

    Human microsomal glutathione transferase 2 (MGST2) is a trimeric integral membrane protein that belongs to the membrane-associated proteins in eicosanoid and glutathione metabolism (MAPEG) family. The mammalian MAPEG family consists of six members where four have been structurally determined. MGST2 activates glutathione to form a thiolate that is crucial for GSH peroxidase activity and GSH conjugation reactions with electrophilic substrates, such as 1-chloro-2,4-dinitrobenzene (CDNB). Several studies have shown that MGST2 is able to catalyze a GSH conjugation reaction with the epoxide LTA(4) forming the pro-inflammatory LTC4. Unlike its closest homologue leukotriene C-4 synthase (LTC4S), MGST2 appears to activate its substrate GSH using only one of the three potential active sites [Ahmad S, et al. (2013) Biochemistry. 52, 1755-1764]. In order to demonstrate and detail the mechanism of one-third of the sites reactivity of MGST2, we have determined the enzyme oligomeric state, by Blue native PAGE and Differential Scanning Calorimetry, as well as the stoichiometty of substrate and substrate analog inhibitor binding to MGST2, using equilibrium dialysis and Isothermal Titration Calorimetry, respectively. Global simulations were used to fit kinetic data to determine the catalytic mechanism of MGST2 with GSH and CDNB (1-chloro-2,4-dinitrobenzene) as substrates. The best fit was observed with 1/3 of the sites catalysis as compared with a simulation where all three sites were active. In contrast to LTC4S, MGST2 displays a 1/3 the sites reactivity, a mechanism shared with the more distant family member MGST1 and recently suggested also for microsomal prostaglandin E synthase-1.

  • 2067. Ahmad, Waqas
    et al.
    Fatima, Aamira
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Awan, Usman Khalid
    Anwar, Arif
    Analysis of long term meteorological trends in the middle and lower Indus Basin of Pakistan-A non-parametric statistical approach2014In: Global and Planetary Change, ISSN 0921-8181, E-ISSN 1872-6364, Vol. 122, p. 282-291Article in journal (Refereed)
    Abstract [en]

    The Indus basin of Pakistan is vulnerable to climate change which would directly affect the livelihoods of poor people engaged in irrigated agriculture. The situation could be worse in middle and lower part of this basin which occupies 90% of the irrigated area. The objective of this research is to analyze the long term meteorological trends in the middle and lower parts of Indus basin of Pakistan. We used monthly data from 1971 to 2010 and applied non-parametric seasonal Kendal test for trend detection in combination with seasonal Kendall slope estimator to quantify the magnitude of trends. The meteorological parameters considered were mean maximum and mean minimum air temperature, and rainfall from 12 meteorological stations located in the study region. We examined the reliability and spatial integrity of data by mass-curve analysis and spatial correlation matrices, respectively. Analysis was performed for four seasons (spring-March to May, summer-June to August-fall-September to November and winter-December to February). The results show that max. temperature has an average increasing trend of magnitude +0.16, +0.03, 0.0 and +0.04 degrees C/decade during all the four seasons, respectively. The average trend of min. temperature during the four seasons also increases with magnitude of +0.29, +0.12, +0.36 and +0.36 degrees C/decade, respectively. Persistence of the increasing trend is more pronounced in the min. temperature as compared to the max. temperature on annual basis. Analysis of rainfall data has not shown any noteworthy trend during winter, fall and on annual basis. However during spring and summer season, the rainfall trends vary from -1.15 to +0.93 and -3.86 to +2.46 mm/decade, respectively. It is further revealed that rainfall trends during all seasons are statistically non-significant. Overall the study area is under a significant warming trend with no changes in rainfall.

  • 2068.
    Ahmadi, Hamid
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Bolinius, Dämien Johann
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Jahnke, Annika
    MacLeod, Matthew
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Mass transfer of hydrophobic organic chemicals between siliconesheets and through plant leaves and low-density polyethylene2016In: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 164, p. 683-690Article in journal (Refereed)
    Abstract [en]

    Plant leaves play an important role in the fate of hydrophobic organic contaminants (HOCs) in theenvironment. Yet much remains unknown about the permeability of leaves by HOCs. In this pilot studywe measured (i) the kinetics of mass transfer of three polycyclic aromatic hydrocarbons (PAHs) and sixpolychlorinated biphenyls between a spiked and an unspiked sheet of polydimethylsiloxane (PDMS) indirect contact with each other for 24 h and (ii) kinetics of mass transfer of two PAHs through leaves andlow-density polyethylene (LDPE) in a passive dosing experiment by inserting these matrices between thetwo sheets of PDMS for 48 h. The kinetics of mass transfer of fluoranthene between PDMS sheets in directcontact were a factor of 12 slower than those reported in the literature. The kinetics of mass transfer offluorene and phenanthrene through leaves were within the range of those previously reported for 2,4-dichlorophenoxyacetic acid through isolated cuticles. Our results provide a proof-of-concept demon-stration that the passive dosing method applied in this study can be used to measure the mass transfercoefficients of organic chemicals through leaves. Key recommendations for future experiments are toload the PDMS at the highest feasible concentrations to avoid working at analyte levels close to the limitof detection, to keep the leaves moist and to minimize potential pathways for contamination of the PDMSsheets by exposure to laboratory air.

  • 2069. Ahmadi, M.
    et al.
    Alves, B. X. R.
    Baker, C. J. .
    Bertsche, W.
    Butler, E.
    Capra, A.
    Carruth, C.
    Cesar, C. L.
    Charlton, M.
    Cohen, S.
    Collister, R.
    Eriksson, S.
    Evans, A.
    Evetts, N.
    Fajans, J.
    Friesen, T.
    Fujiwara, M. C.
    Gill, D. R.
    Gutierrez, A.
    Hangst, J. S.
    Hardy, W. N.
    Hayden, M. E.
    Isaac, C. A.
    Ishida, A.
    Ohnson, M. A. J.
    Ones, S. A. J.
    Jonsell, Svante
    Stockholm University, Faculty of Science, Department of Physics.
    Kurchaninov, L.
    Madsen, N.
    Mathers, M.
    Maxwell, D.
    McKenna, J. T. K.
    Menary, S.
    Michan, J. M.
    Momose, T.
    Munich, J. J. .
    Nolan, P.
    Olchanski, K.
    Olin, A.
    Pusa, P.
    Rasmussen, C. O.
    Robicheaux, F.
    Sacramento, R. L.
    Sameed, M.
    Sarid, E.
    Silveira, D. M.
    Stracka, S.
    Stutter, G.
    So, C.
    Tharp, T. D.
    Thompson, J. E.
    Thompson, R. I.
    van der Werf, D. P.
    Wurtele, J. S.
    Observation of the 1S-2S transition in trapped antihydrogen2017In: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 541, no 7638, p. 506-510Article in journal (Refereed)
    Abstract [en]

    The spectrum of the hydrogen atom has played a central part in fundamental physics over the past 200 years. Historical examples of its importance include the wavelength measurements of absorption lines in the solar spectrum by Fraunhofer, the identification of transition lines by Balmer, Lyman and others, the empirical description of allowed wavelengths by Rydberg, the quantum model of Bohr, the capability of quantum electrodynamics to precisely predict transition frequencies, and modern measurements of the 1S-2S transition by Hansch1 to a precision of a few parts in 10(15). Recent technological advances have allowed us to focus on antihydrogen-the antimatter equivalent of hydrogen(2-4). The Standard Model predicts that there should have been equal amounts of matter and antimatter in the primordial Universe after the Big Bang, but today's Universe is observed to consist almost entirely of ordinary matter. This motivates the study of antimatter, to see if there is a small asymmetry in the laws of physics that govern the two types of matter. In particular, the CPT (charge conjugation, parity reversal and time reversal) theorem, a cornerstone of the Standard Model, requires that hydrogen and antihydrogen have the same spectrum. Here we report the observation of the 1S-2S transition in magnetically trapped atoms of antihydrogen. We determine that the frequency of the transition, which is driven by two photons from a laser at 243 nanometres, is consistent with that expected for hydrogen in the same environment. This laser excitation of a quantum state of an atom of antimatter represents the most precise measurement performed on an anti-atom. Our result is consistent with CPT invariance at a relative precision of about 2 x 10(-10).

  • 2070. Ahmadi, M.
    et al.
    Alves, B. X. R.
    Baker, C. J.
    Bertsche, W.
    Butler, E.
    Capra, A.
    Carruth, C.
    Cesar, C. L.
    Charlton, M.
    Cohen, S.
    Collister, R.
    Eriksson, S.
    Evans, A.
    Evetts, N.
    Fajans, J.
    Friesen, T.
    Fujiwara, M. C.
    Gill, D. R.
    Gutierrez, A.
    Hangst, J. S.
    Hardy, W. N.
    Hayden, M. E.
    Isaac, C. A.
    Ishida, A.
    Johnson, M. A.
    Jones, S. A.
    Jonsell, Svante
    Stockholm University, Faculty of Science, Department of Physics.
    Kurchaninov, L.
    Madsen, N.
    Mathers, M.
    Maxwell, D.
    McKenna, J. T. K.
    Menary, S.
    Michan, J. M.
    Momose, T.
    Munich, J. J.
    Nolan, P.
    Olchanski, K.
    Olin, A.
    Pusa, P.
    Rasmussen, C. O.
    Robicheaux, F.
    Sacramento, R. L.
    Sameed, M.
    Sarid, E.
    Silveira, D. M.
    Stracka, S.
    Stutter, G.
    So, C.
    Tharp, T. D.
    Thompson, J. E.
    Thompson, R. I.
    Van der Werf, D. P.
    Wurtele, J. S.
    Observation of the hyperfine spectrum of antihydrogen2017In: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 548, no 7665, p. 66-+Article in journal (Refereed)
    Abstract [en]

    The observation of hyperfine structure in atomic hydrogen by Rabi and co-workers(1-3) and the measurement(4) of the zero-field ground-state splitting at the level of seven parts in 10(13) are important achievements of mid-twentieth-century physics. The work that led to these achievements also provided the first evidence for the anomalous magnetic moment of the electron(5-8), inspired Schwinger's relativistic theory of quantum electrodynamics(9,10) and gave rise to the hydrogen maser(11), which is a critical component of modern navigation, geo-positioning and very-long-baseline interferometry systems. Research at the Antiproton Decelerator at CERN by the ALPHA collaboration extends these enquiries into the antimatter sector. Recently, tools have been developed that enable studies of the hyperfine structure of antihydrogen(12)-the antimatter counterpart of hydrogen. The goal of such studies is to search for any differences that might exist between this archetypal pair of atoms, and thereby to test the fundamental principles on which quantum field theory is constructed. Magnetic trapping of antihydrogen atoms(13,14) provides a means of studying them by combining electromagnetic interaction with detection techniques that are unique to antimatter(12,15). Here we report the results of a microwave spectroscopy experiment in which we probe the response of antihydrogen over a controlled range of frequencies. The data reveal clear and distinct signatures of two allowed transitions, from which we obtain a direct, magnetic-field-independent measurement of the hyperfine splitting. From a set of trials involving 194 detected atoms, we determine a splitting of 1,420.4 +/- 0.5 megahertz, consistent with expectations for atomic hydrogen at the level of four parts in 10(4). This observation of the detailed behaviour of a quantum transition in an atom of antihydrogen exemplifies tests of fundamental symmetries such as charge-parity-time in antimatter, and the techniques developed here will enable more-precise such tests.

  • 2071. Ahmadi, M.
    et al.
    Alves, B. X. R.
    Baker, C. J.
    Bertsche, W.
    Butler, E.
    Capra, A.
    Carruth, C.
    Cesar, C. L.
    Charlton, M.
    Cohen, S.
    Collister, R.
    Eriksson, S.
    Evans, A.
    Evetts, N.
    Fajans, J.
    Friesen, T.
    Fujiwara, M. C.
    Gill, D. R.
    Gutierrez, A.
    Hangst, J. S.
    Hardy, W. N.
    Hayden, M. E.
    Isaac, C. A.
    Ishida, A.
    Johnson, M. A.
    Jones, S. A.
    Jonsell, Svante
    Stockholm University, Faculty of Science, Department of Physics.
    Kurchaninov, L.
    Madsen, N.
    Mathers, M.
    Maxwell, D.
    McKenna, J. T. K.
    Menary, S.
    Michan, J. M.
    Momose, T.
    Munich, J. J.
    Nolan, P.
    Olchanski, K.
    Olin, A.
    Pusa, P.
    Rasmussen, C. Ø.
    Robicheaux, F.
    Sacramento, R. L.
    Sameed, M.
    Sarid, E.
    Silveira, D. M.
    Stracka, S.
    Stutter, G.
    So, C.
    Tharp, T. D.
    Thompson, J. E.
    Thompson, R. I.
    van der Werf, D. P.
    Wurtele, J. S.
    Antihydrogen accumulation for fundamental symmetry tests2017In: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 8, article id 681Article in journal (Refereed)
    Abstract [en]

    Antihydrogen, a positron bound to an antiproton, is the simplest anti-atom. Its structure and properties are expected to mirror those of the hydrogen atom. Prospects for precision comparisons of the two, as tests of fundamental symmetries, are driving a vibrant programme of research. In this regard, a limiting factor in most experiments is the availability of large numbers of cold ground state antihydrogen atoms. Here, we describe how an improved synthesis process results in a maximum rate of 10.5 +/- 0.6 atoms trapped and detected per cycle, corresponding to more than an order of magnitude improvement over previous work. Additionally, we demonstrate how detailed control of electron, positron and antiproton plasmas enables repeated formation and trapping of antihydrogen atoms, with the simultaneous retention of atoms produced in previous cycles. We report a record of 54 detected annihilation events from a single release of the trapped anti-atoms accumulated from five consecutive cycles.

  • 2072. Ahmadi, M.
    et al.
    Alves, B. X. R.
    Baker, C. J.
    Bertsche, W.
    Capra, A.
    Carruth, C.
    Cesar, C. L.
    Charlton, M.
    Cohen, S.
    Collister, R.
    Eriksson, S.
    Evans, A.
    Evetts, N.
    Fajans, J.
    Friesen, T.
    Fujiwara, M. C.
    Gill, D. R.
    Hangst, J. S.
    Hardy, W. N.
    Hayden, M. E.
    Hunter, E. D.
    Isaac, C. A.
    Johnson, M. A.
    Jones, J. M.
    Jones, S. A.
    Jonsell, Svante
    Stockholm University, Faculty of Science, Department of Physics.
    Khramov, A.
    Knapp, P.
    Kurchaninov, L.
    Madsen, N.
    Maxwell, D.
    McKenna, J. T. K.
    Menary, S.
    Michan, J. M.
    Momose, T.
    Munich, J. J.
    Olchanski, K.
    Olin, A.
    Pusa, P.
    Rasmussen, C. O.
    Robicheaux, F.
    Sacramento, R. L.
    Sameed, M.
    Sarid, E.
    Silveira, D. M.
    Starko, D. M.
    Stutter, G.
    So, C.
    Tharp, T. D.
    Thompson, R. I.
    van der Werf, D. P.
    Wurtele, J. S.
    Observation of the 1S-2P Lyman-alpha transition in antihydrogen2018In: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 561, no 7722, p. 211-217Article in journal (Refereed)
    Abstract [en]

    In 1906, Theodore Lyman discovered his eponymous series of transitions in the extreme-ultraviolet region of the atomic hydrogen spectrum(1,2). The patterns in the hydrogen spectrum helped to establish the emerging theory of quantum mechanics, which we now know governs the world at the atomic scale. Since then, studies involving the Lyman-alpha line-the 1S-2P transition at a wavelength of 121.6 nanometres-have played an important part in physics and astronomy, as one of the most fundamental atomic transitions in the Universe. For example, this transition has long been used by astronomers studying the intergalactic medium and testing cosmological models via the so-called 'Lyman-alpha forest('3) of absorption lines at different redshifts. Here we report the observation of the Lyman-alpha transition in the antihydrogen atom, the antimatter counterpart of hydrogen. Using narrow-line-width, nanosecond-pulsed laser radiation, the 1S-2P transition was excited in magnetically trapped antihydrogen. The transition frequency at a field of 1.033 tesla was determined to be 2,466,051.7 +/- 0.12 gigahertz (1 sigma uncertainty) and agrees with the prediction for hydrogen to a precision of 5 x 10(-8). Comparisons of the properties of antihydrogen with those of its well-studied matter equivalent allow precision tests of fundamental symmetries between matter ;and antimatter. Alongside the ground-state hyperfine(4,5) and 1S-2S transitions(6,7) recently observed in antihydrogen, the Lyman-alpha transition will permit laser cooling of antihydrogen(8,9), thus providing a cold and dense sample of anti-atoms for precision spectroscopy and gravity measurements(10). In addition to the observation of this fundamental transition, this work represents both a decisive technological step towards laser cooling of antihydrogen, and the extension of antimatter spectroscopy to quantum states possessing orbital angular momentum.

  • 2073. Ahmadi, M.
    et al.
    Alves, B. X. R.
    Baker, C. J.
    Bertsche, W.
    Capra, A.
    Carruth, C.
    Cesar, C. L.
    Charlton, M.
    Cohen, S.
    Collister, R.
    Eriksson, S.
    Evans, A.
    Evetts, N.
    Fajans, J.
    Friesen, T.
    Fujiwara, M. C.
    Gill, D. R.
    Hangst, J. S.
    Hardy, W. N.
    Hayden, M. E.
    Isaac, C. A.
    Johnson, M. A.
    Jones, J. M.
    Jones, S. A.
    Jonsell, Svante
    Stockholm University, Faculty of Science, Department of Physics.
    Khramov, A.
    Knapp, P.
    Kurchaninov, L.
    Madsen, N.
    Maxwell, D.
    McKenna, J. T. K.
    Menary, S.
    Momose, T.
    Munich, J. J.
    Olchanski, K.
    Olin, A.
    Pusa, P.
    Rasmussen, C. O.
    Robicheaux, F.
    Sacramento, R. L.
    Sameed, M.
    Sarid, E.
    Silveira, D. M.
    Stutter, G.
    So, C.
    Tharp, T. D.
    Thompson, R. I.
    van der Werf, D. P.
    Wurtele, J. S.
    Characterization of the 1S-2S transition in antihydrogen2018In: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 557, no 7703, p. 71-+Article in journal (Refereed)
    Abstract [en]

    In 1928, Dirac published an equation(1) that combined quantum mechanics and special relativity. Negative-energy solutions to this equation, rather than being unphysical as initially thought, represented a class of hitherto unobserved and unimagined particles-antimatter. The existence of particles of antimatter was confirmed with the discovery of the positron(2) (or anti-electron) by Anderson in 1932, but it is still unknown why matter, rather than antimatter, survived after the Big Bang. As a result, experimental studies of antimatter(3-7), including tests of fundamental symmetries such as charge-parity and charge-parity-time, and searches for evidence of primordial antimatter, such as antihelium nuclei, have high priority in contemporary physics research. The fundamental role of the hydrogen atom in the evolution of the Universe and in the historical development of our understanding of quantum physics makes its antimatter counterpart-the antihydrogen atom-of particular interest. Current standard-model physics requires that hydrogen and antihydrogen have the same energy levels and spectral lines. The laser-driven 1S-2S transition was recently observed(8) in antihydrogen. Here we characterize one of the hyperfine components of this transition using magnetically trapped atoms of antihydrogen and compare it to model calculations for hydrogen in our apparatus. We find that the shape of the spectral line agrees very well with that expected for hydrogen and that the resonance frequency agrees with that in hydrogen to about 5 kilohertz out of 2.5 x 10(15) hertz. This is consistent with charge-parity-time invariance at a relative precision of 2 x 10(-12)-two orders of magnitude more precise than the previous determination(8)-corresponding to an absolute energy sensitivity of 2 x 10(-20) GeV.

  • 2074. Ahmadi, M.
    et al.
    Alves, B. X. R.
    Baker, C. J.
    Bertsche, W.
    Capra, A.
    Carruth, C.
    Cesar, C. L.
    Charlton, M.
    Cohen, S.
    Collister, R.
    Eriksson, S.
    Evans, A.
    Evetts, N.
    Fajans, J.
    Friesen, T.
    Fujiwara, M. C.
    Gill, D. R.
    Hangst, J. S.
    Hardy, W. N.
    Hayden, M. E.
    Isaac, C. A.
    Johnson, M. A.
    Jones, S. A.
    Jonsell, Svante
    Stockholm University, Faculty of Science, Department of Physics.
    Kurchaninov, L.
    Madsen, N.
    Mathers, M.
    Maxwell, D.
    McKenna, J. T. K.
    Menary, S.
    Momose, T.
    Munich, J. J.
    Olchanski, K.
    Olin, A.
    Pusa, P.
    Rasmussen, C. O.
    Robicheaux, F.
    Sacramento, R. L.
    Sameed, M.
    Sarid, E.
    Silveira, D. M.
    So, C.
    Stutter, G.
    Tharp, T. D.
    Thompson, J. E.
    Thompson, R. I.
    van der Werf, D. P.
    Wurtele, J. S.
    Enhanced Control and Reproducibility of Non-Neutral Plasmas2018In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 120, no 2, article id 025001Article in journal (Refereed)
    Abstract [en]

    The simultaneous control of the density and particle number of non-neutral plasmas confined in Penning-Malmberg traps is demonstrated. Control is achieved by setting the plasma's density by applying a rotating electric field while simultaneously fixing its axial potential via evaporative cooling. This novel method is particularly useful for stabilizing positron plasmas, as the procedures used to collect positrons from radioactive sources typically yield plasmas with variable densities and particle numbers; it also simplifies optimization studies that require plasma parameter scans. The reproducibility achieved by applying this technique to the positron and electron plasmas used by the ALPHA antihydrogen experiment at CERN, combined with other developments, contributed to a 10-fold increase in the antiatom trapping rate.

  • 2075. Ahmadi, M.
    et al.
    Baquero-Ruiz, M.
    Bertsche, W.
    Butler, E.
    Capra, A.
    Carruth, C.
    Cesar, C. L.
    Charlton, M.
    Charman, A. E.
    Eriksson, S.
    Evans, L. T.
    Evetts, N.
    Fajans, J.
    Friesen, T.
    Fujiwara, M. C.
    Gill, D. R.
    Gutierrez, A.
    Hangst, J. S.
    Hardy, W. N.
    Hayden, M. E.
    Isaac, C. A.
    Ishida, A.
    Jones, S. A.
    Jonsell, Svante
    Stockholm University, Faculty of Science, Department of Physics.
    Kurchaninov, L.
    Madsen, N.
    Maxwell, D.
    McKenna, J. T. K.
    Menary, S.
    Michan, J. M.
    Momose, T.
    Munich, J. J.
    Nolan, P.
    Olchanski, K.
    Olin, A.
    Povilus, A.
    Pusa, P.
    Rasmussen, C. O.
    Robicheaux, F.
    Sacramento, R. L.
    Sameed, M.
    Sarid, E.
    Silveira, D. M.
    So, C.
    Tharp, T. D.
    Thompson, R. I.
    van der Werf, D. P.
    Wurtele, J. S.
    Zhmoginov, A. I.
    An improved limit on the charge of antihydrogen from stochastic acceleration2016In: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 529, no 7586, p. 373-+Article in journal (Refereed)
    Abstract [en]

    Antimatter continues to intrigue physicists because of its apparent absence in the observable Universe. Current theory requires that matter and antimatter appeared in equal quantities after the Big Bang, but the Standard Model of particle physics offers no quantitative explanation for the apparent disappearance of half the Universe. It has recently become possible to study trapped atoms(1-4) of antihydrogen to search for possible, as yet unobserved, differences in the physical behaviour of matter and antimatter. Here we consider the charge neutrality of the antihydrogen atom. By applying stochastic acceleration to trapped antihydrogen atoms, we determine an experimental bound on the antihydrogen charge, Qe, of vertical bar Q vertical bar < 0.71 parts per billion (one standard deviation), in which e is the elementary charge. This bound is a factor of 20 less than that determined from the best previous measurement(5) of the antihydrogen charge. The electrical charge of atoms and molecules of normal matter is known(6) to be no greater than about 10(-21)e for a diverse range of species including H-2, He and SF6. Charge-parity-time symmetry and quantum anomaly cancellation(7) demand that the charge of antihydrogen be similarly small. Thus, our measurement constitutes an improved limit and a test of fundamental aspects of the Standard Model. If we assume charge superposition and use the best measured value of the antiproton charge(8), then we can place a new limit on the positron charge anomaly (the relative difference between the positron and elementary charge) of about one part per billion (one standard deviation), a 25-fold reduction compared to the current best measurement(8),(9).

  • 2076.
    Ahmadi, Mazaher
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Bu-Ali Sina University, Iran.
    Elmongy, Hatem
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Madrakian, Tayyebeh
    Abdel-Rehim, Mohamed
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Nanomaterials as sorbents for sample preparation in bioanalysis: A review2017In: Analytica Chimica Acta, ISSN 0003-2670, E-ISSN 1873-4324, Vol. 958, p. 1-21Article, review/survey (Refereed)
    Abstract [en]

    In recent years, application of nanomaterials as sorbent has gained the attention of researchers in bioanalysis. Different nanomaterials have been utilized as the sorbent in extraction techniques such as solid phase extraction, dispersive solid phase extraction, magnetic solid phase extraction, microextraction by packed sorbent, solid phase microextraction, dispersive pt-solid phase extraction, and stir bar sorptive extraction. In the present review, different nanomaterials which have recently been utilized as sorbent for bioanalysis are classified into six main groups, namely metallic, metallic and mixed oxide, magnetic, carbonaceous, silicon, and polymer-based nanomaterials. Application of these nanomaterials in different extraction techniques for bioanalysis has been reviewed. This study shows that magnetic nanomaterials have gained significant attention owing to their magnetic separation ability. In addition, the present review shows that there is a lack in the application of nanomaterials for on-line analysis procedures, most probably due to some intrinsic properties of nanomaterials such as spontaneous agglomeration.

  • 2077. Ahmadi-Afzadi, Masoud
    et al.
    Orsel, Mathilde
    Pelletier, Sandra
    Bruneau, Maryline
    Proux-Wéra, Estelle
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics. Stockholm University, Science for Life Laboratory (SciLifeLab). Swedish University of Agricultural Sciences, Sweden.
    Nybom, Hilde
    Renou, Jean-Pierre
    Genome-wide expression analysis suggests a role for jasmonates in the resistance to blue mold in apple2018In: Plant growth regulation (Print), ISSN 0167-6903, E-ISSN 1573-5087, Vol. 85, no 3, p. 375-387Article in journal (Refereed)
    Abstract [en]

    Blue mold, caused by the necrotrophic fungal pathogen Penicillium expansum, causes serious postharvest losses in apple, and threatens human health through production of the potent mycotoxin patulin. Recent studies indicate a quantitative control of resistance against this disease in apple cultivars. A whole genome apple microarray covering 60k transcripts was used to identify gene(s) that appear to be differentially regulated between resistant and susceptible cultivars in P. expansum-infected fruits. A number of potential candidates was encountered among defense- and oxidative stress-related genes, cell wall modification and lignification genes, and genes related to localization and transport. Induction of one cell wall-related gene and three genes involved in the 'down-stream' flavonoid biosynthesis pathway, demonstrates the fundamental role of the cell wall as an important barrier, and suggests that fruit flavonoids are involved in the resistance to blue mold. Moreover, exogenous application of the plant hormone methyl jasmonate (MeJA) reduced the symptoms resulting from inoculating apples with P. expansum. This is the first report linking MeJA and activation of cell wall and flavonoid pathway genes to resistance against blue mold in a study comparing different cultivars of domesticated apple. Our results provide an initial categorization of genes that are potentially involved in the resistance mechanism, and should be useful for developing tools for gene marker-assisted breeding of apple cultivars with an improved resistance to blue mold.

  • 2078. Ahmed, Adamu
    et al.
    Adama, Onyanta
    Stockholm University, Faculty of Social Sciences, Department of Human Geography.
    Iliyasu, Idris
    Prospects and Retrospect: Insights from Children's participation in Informal Sector Solid Waste Management in Kaduna, Nigeria2017In: Dealing with waste: Resource Recovery and Entrepreneurship in Informal Sector Solid Waste Management in African Cities / [ed] Onyanta Adama, Tadischi Chidi Nzeadibe, Africa World Press, 2017, p. 137-150Chapter in book (Other academic)
  • 2079.
    Ahmed, Engy
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Microbe-mineral interactions in soil: Investigation of biogenic chelators, microenvironments and weathering processes2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The interplay between geology and biology has shaped the Earth during billions of years. Microbe-mineral interactions are prime examples of this interplay and underscore the importance of microorganisms in making Earth a suitable environment for all forms of life. The present thesis takes an interdisciplinary approach to obtain an integrated understanding of microbe-mineral interactions. More specifically it addresses how the composition and distribution of biogenic weathering agents (siderophores) differ with regard to soil horizon and mineral type in situ, what siderophore type soil microorganisms produces under laboratory conditions, what role microbial surface attachment plays in mineral weathering reactions and what central roles and applications siderophores have in the environment.

    Podzol, the third most abundant soil in Europe, and most abundant in Scandinavia, was chosen for a field experiment, where three minerals (apatite, biotite and oligoclase) were inserted in the organic, eluvial and upper illuvial soil horizons. The study started with an investigation of the siderophore composition in the bulk soil profile and on the mineral surfaces (paper I), which was followed by a study of the siderophore producing capabilities of microorganisms isolated from the soil profile under laboratory conditions (paper II). Subsequently, a study was done on the impact of microbial surface attachment on biotite dissolution (paper III). Finally, the roles of siderophores in nature and their potential applications were reviewed (paper IV).

    The major findings were that the concentration of hydroxamate siderophores in the soil attached to the mineral surfaces was greater than those in the surrounding bulk soil, indicating that the minerals stimulate the microbial communities attached to their surfaces to produce more siderophores than the microorganisms in the bulk soil. Each mineral had a unique assemblage of hydroxamate siderophores, that makes the mineral type one of the main factors affecting siderophore composition in the natural environment. Siderophore production varied between the microbial species originating from different soil horizons, suggesting that the metabolic properties of microbes in deep soil horizons function differently from those at upper soil horizons. Microbial surface attachment enhanced the biotite dissolution, showing that attached microbes has a greater influence on weathering reactions in soil than planktonic populations. In conclusion, our findings reflected that the complicated relationship between microorganisms and mineral surfaces reinforces the central theme of biogeochemistry that the mineral controls the biological activity in the natural environments. However, the importance of these relationships to the biogeochemical systems requires further investigation.

  • 2080.
    Ahmed, Engy
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    The interaction between microbes, siderophores and minerals in podzol soil2013Licentiate thesis, comprehensive summary (Other academic)
  • 2081.
    Ahmed, Engy
    et al.
    Stockholm University, Faculty of Science, Department of Geological Sciences. Stockholm University, Science for Life Laboratory (SciLifeLab).
    Abdulla, Hesham M.
    Mohamed, Amy H.
    El-Bassuony, Ahmed D.
    Remediation and recycling of chromium from tannery wastewater using combined chemical-biological treatment system2016In: Process Safety and Environmental Protection, ISSN 0957-5820, E-ISSN 1744-3598, Vol. 104, p. 1-10Article in journal (Refereed)
    Abstract [en]

    Tannery wastewater containing chromium (Cr) is one of the most serious problems in leather industry. In order to develop an effective and eco-friendly treatment technology, a combined chemical-biological treatment system was performed for Cr remediation and recycling. The aim of the present study is to design a laboratory scale system using chemical precipitation of Cr(III) combined with biological removal of Cr(VI) from tannery wastewater, and to investigate the possibility of recycling the recovered Cr(III) in the tanning industry. Chemical precipitation of Cr(III) was carried out using lime and cement dust. The actinomycete strain Kitasatosporia sp. was used in microcosm studies for Cr(VI) bioremoval. Moreover, parameters such as type of porous medium, inoculum size, flow rate and culture conditions were investigated. The precipitated Cr(III) that was recovered from the chemical precipitation stage was recycled in the leather tanning industry. Our findings indicate that the maximum Cr(III) precipitation (98%) was achieved using 2 g/100 mL of lime and 2 h of settling rate. On the other hand, microcosm columns using sand that was inoculated with induced culture (OD600 = 2.43) and flow rate (2 mL/min) gave the maximum recovery (99%) of Cr(VI). The experimental Cr(III) was successfully recycled in the tanning process and the experimental leathers showed comparable properties as same as the leathers tanned with commercial Cr(III). Thus, we concluded that using combined chemical-biological treatment system for Cr remediation from tanning wastewater together with recycling process for the recovered Cr(III) is a promising strategy for economic and environmental friendly tanning industry.

  • 2082.
    Ahmed, Engy
    et al.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Holmström, Sara
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Soil Microorganisms and Mineral Weathering: Mechanics of Biotite Dissolution2012Conference paper (Other academic)
    Abstract [en]

    Soil microorganisms play an important role in the environment by contributing to leach and release of essential elements from soil minerals that are required not only for their own nutrition but also for plants growth. This study aims to compare between the mechanisms of different fungal and bacterial species isolated from podzol soil in biotite dissolution. Microplate devices with 6 wells were used for the biological weathering experiments. All of the sterilized microplate wells were filled with 4g/l of biotite followed by 12 ml of an iron free diluted mineral liquid medium. In these conditions, biotite particles are the only source of the essential elements for the microorganisms. To characterize the mechanisms of biotite dissolution, we monitored siderophores production, microbial biomass, pH, exchangeable cations concentration and SEM analysis for mineral surface. There was a significant difference between the behavior of the fungal and bacterial species in dissolution of biotite. This difference may be due to the variation of these microorganisms in their mechanics of interaction with mineral surface. It was observed also that these microorganisms directly and indirectly induce biotite dissolution. Defining soil as a system driven by biological mechanisms rather than chemical processes has major implications for our understanding of how the system functions and how it will respond to changing conditions.

  • 2083.
    Ahmed, Engy
    et al.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Holmström, Sara
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    THE MICROBE-MINERAL INTERACTIONS IN THE ACIDIC PODZOL SOIL2013In: Mineralogical magazine, ISSN 0026-461X, E-ISSN 1471-8022, Vol. 77, no 5, p. 564-Article in journal (Other (popular science, discussion, etc.))
    Abstract [en]

    Iron is a key component of the chemical architecture of the biosphere. Due to the low bioavailability of iron in the environment, microorganisms have developed specific uptake strategies, like siderophores, which are operationally defined as low-molecular-mass biogenic Fe(III)-binding compounds, that can increase iron’s bioavailability by promoting the dissolution of iron-bearing minerals. In the present study, we aimed to investigate the composition of hydroxamate siderophores in the soil horizons of the acidic podzol, and study how they are affected by the presence of specific mineral types and microbial communities.

     Three different minerals (apatite, biotite and oligioclase) were inserted in the soil horizons (O (organic), E (eluvial), B (upper illuvial), and C (mineral)). After two years, soil samples were collected from both the bulk soil (next to the minerals) and from the soil attached to the mineral surfaces. The concentration of ten different fungal tri-hydroxamates and five bacterial ones were determined by high-performance liquid chromatography coupled to electrospray ionization mass spectrometry (HPLC-ESI-MS). In addition, total microbial composition and diversity were studied.

    Our field experiment succeeded in describing the relationship between the presence of siderophores, soil horizon and mineral type, in addition to understanding the interaction between mineral type and soil microbial composition. A wide range of fungal and bacterial hydroxamates were detected throughout the soil profile. On the other hand, the presence of the minerals completely altered the diversity of siderophores. In addition, each mineral had a unique interaction with hydroxamates in the different soil horizons. There were also a good relationship between the microbial diversity and the siderophore distribution. 

  • 2084.
    Ahmed, Engy
    et al.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Holmström, Sara
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    The Roles and Applications of Siderophores in Natural Environments2013Conference paper (Other academic)
    Abstract [en]

    Siderophores are organic compounds with low molecular mass that are produced by microorganisms growing under conditions of low iron. The primary function of these compounds is to chelate ferric iron from different terrestrial and aquatic habitats and thereby make it available for microbial cells.

    Siderophores have received much attention in recent years because of their potential roles and applications in various areas of environmental research. For instance, the production of siderophores can provide a quick identification of microbes to the species level that called “siderotyping”. On the other hand, siderophores could also function as biocontrol, biosensor, and bioremediation agents, in addition to their important role in mineral weathering and enhancing plant growth. In the present study, we aimed to investigate the composition of trihydroxamate siderophores in soil samples from different horizons (O (organic), E (eluvial), B (upper illuvial), and C (parent material)) of a podzol soil in Sweden, and study how they are affected by the presence of specific mineral types (apatite, biotite and oligioclase) that were inserted in the soil for two years in a field experiment.

    Our field experiment succeeded in describing the relationship between the presence of siderophores, soil horizons and mineral types. A wide range of fungal and bacterial hydroxamates were detected throughout the soil profile. On the other hand, the presence of the minerals completely altered the diversity of siderophores. In addition, each mineral had a unique interaction with hydroxamates in the different soil horizons. Our next step is to gain greater insight into the siderotyping to illustrate the relationship between the siderophore types that was found throughout the soil profile and on the different mineral surfaces and the microbial diversity by using metagenomic applications.

  • 2085.
    Ahmed, Engy
    et al.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Holmström, Sara
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Brüchert, Volker
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Holm, Nils G.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    The Role of Microorganisms in the diversity and distribution of siderophores in Podzolic Forest Soil2013In: Mineralogical magazine, ISSN 0026-461X, E-ISSN 1471-8022, Vol. 77, no 2, p. 161--208(48)Article in journal (Other academic)
    Abstract [en]

    Iron is a key component of the chemical architecture of the biosphere. Due to the low bioavailability of iron in the environment, microorganisms have developed specific uptake strategies. The most important one is the production of siderophores, which are operationally defined as low-molecular-mass biogenic Fe (III)-binding compounds which may greatly increase bioavailability of Fe [1]. One of the primary biogeochemical functions of siderophores is therefore to increase Fe bioavailability by promoting the dissolution of iron-bearing minerals [2]. This study aims to understand the role of microorganisms in the chemical diversity and distribution of siderophores in podzol soil and how this diversity can contribute to the bioavailability of Fe in forest soil.Soil samples were collected from an experimental site in the area of Bispgården in central Sweden (63°07′N, 16°70′E) from the O (organic), E (eluvial), B1 (upper illuvial), and C (mineral) horizons. Concentration and chemical composition of dissolved and adsorbed siderophores in the soil samples were determined using colorimetric assays and high-performance liquid chromatography.The highest siderophore concentrations were found in the O layer and thereafter decreased by depth. Concentrations of dissolved hydroxamate, catecholate and carboxylate siderophores were up to 84, 17 and 0.2 nmol/ g soil, respectively. In contrast, concentrations of adsorbed hydroxamates, catecholates and carboxylates were only up to 1.8, 3 and 0.2 nmol/ g soil, respectively.Siderophore-producing microorganisms were isolated from the same soil samples. Viable fungi, bacteria and actinomycete counts ranged from 7 to 300, from 300 to 1800, and from 0 to 5 cfu/gm, respectively. The highest counts were found in the O and E layers. Only the E layer contained the three types of siderophore-producing microorganisms investigated in this study. Siderophores were extracted from culture filtrates of the isolated microorganisms when grown under iron-limited conditions. These extracts varied considerably in siderophore composition. Fungal isolates produced up to 183 μM of hydroxamates, especially those isolated from the O layer, whereas bacteria and actinomycete isolated from the O and E layers of the soil produced high amounts of carboxylate, catecholate and hydroxamate siderophores. Actinomycete produced up to 93 μM of hydroxamates and 47 μM of catecholates, while bacteria produced up to 34 μM of carboxylates and up to 14 μM of catecholates.The depth variability in concentration and chemical composition and the good correlation between abundance of siderophore-producing microorganisms and siderophore soil concentrations strongly suggest that these siderophore-producing microorganisms play an important role in the mobilization of iron in the podzol soil that may be important in iron availability to plants in forest environment.

    [1] Clay et al. (1981) Biochemistry 20, 2432-2436. [2] Duckworth et al. (2009) ChemGeol 260, 149-158.

  • 2086.
    Ahmed, Engy
    et al.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Holmström, Sara J. M.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Microbe-mineral interactions: The impact of surface attachment on mineral weathering and element selectivity by microorganisms2015In: Chemical Geology, ISSN 0009-2541, E-ISSN 1872-6836, Vol. 403, p. 13-23Article in journal (Refereed)
    Abstract [en]

    One of the major gaps within the field of biogeochemistry is the lack of a detailed and deep understanding of the mechanismbehind the microbial inducement of mineral dissolution. The association of microorganisms with the mineral surfaces is an important issue for understanding processes like mineral weathering, biomineralization, bioremediation and biofouling. The present study aims to investigate the performance of attached and unattached soil fungal and bacterial species in biotite weathering and in the selectivity of elements from biotite. Sterilized microplate devices were filled with biotite (>2 mm) followed by an iron limited liquid growth medium and were inoculated separately with six different microbial species isolated from podzol soil: Erwinia amylovora, Pseudomonas stutzeri, Pseudomonas mendocina, Streptomyces pilosus, Neurospora crassa and Penicillium melinii. The experiment was designed in two set-ups: 1) attached form, in which the microorganisms were inoculated directly to the biotite surface, and 2) unattached form, in which 0.4 mu m PET track etched devices were used to separate the microbial cells from the biotite surface. Our findings indicate that the surface attached microorganisms led to a greater dissolution of elements from biotite than the unattached microorganisms that was evidenced by 1) higher dissolution of Fe, Al and Si, 2) greater decrease in pH of the liquid growth medium, and 3) relatively higher production of siderophores. Furthermore, there was no significant difference in the capability of element selectivity between the attached and unattached microbial forms. The biotite dissolution was promoted initially by complexation processes and later by acidification processes for most of the attached and unattached microorganisms. Thus, we conclude that despite the mineral dissolution induced by microbial attachment on the mineral surface, the element composition of the biotite and nutritional need of the microorganisms were the main factors affecting the element selectivity.

  • 2087.
    Ahmed, Engy
    et al.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Holmström, Sara J. M.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Siderophore Production by Microorganisms Isolated From a Podzol Soil Profile2015In: Geomicrobiology Journal, ISSN 0149-0451, E-ISSN 1521-0529, Vol. 32, no 5, p. 397-411Article in journal (Refereed)
    Abstract [en]

    Siderophore-producing bacteria/actinobacteria and fungi were isolated from O- (organic), E- (eluvial), B- (upper illuvial), and C- (parent material) horizons of podzol soil. Siderophores were isolated and hydroxamate type siderophores were detected and quantitated by high-performance liquid chromatography coupled to electrospray ionization mass spectrometry. The molecular identification of siderophore-producing isolates showed that there was a high diversity of fungal and bacterial/actinobacterial species throughout the soil profile. The isolated bacteria/actinobacteria showed different abilities in the production of ferrioxamines (E, B, G and D). Moreover, the isolated fungal species showed great variety in the production of ferrichromes, coprogens and fusarinines.

  • 2088.
    Ahmed, Engy
    et al.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Holmström, Sara J. M.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Siderophores in environmental research: roles and applications2014In: Microbial Biotechnology, ISSN 1751-7907, E-ISSN 1751-7915, Vol. 7, no 3, p. 196-208Article, review/survey (Refereed)
    Abstract [en]

    Siderophores are organic compounds with low molecular masses that are produced by microorganisms and plants growing under low iron conditions. The primary function of these compounds is to chelate the ferric iron [Fe(III)] from different terrestrial and aquatic habitats and thereby make it available for microbial and plant cells. Siderophores have received much attention in recent years because of their potential roles and applications in various areas of environmental research. Their significance in these applications is because siderophores have the ability to bind a variety of metals in addition to iron, and they have a wide range of chemical structures and specific properties. For instance, siderophores function as biocontrols, biosensors, and bioremediation and chelation agents, in addition to their important role in weathering soil minerals and enhancing plant growth. The aim of this literature review is to outline and discuss the important roles and functions of siderophores in different environmental habitats and emphasize the significant roles that these small organic molecules could play in applied environmental processes.

  • 2089.
    Ahmed, Engy
    et al.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Holmström, Sara J. M.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    The effect of soil horizon and mineral type on the distribution of siderophores in soil2014In: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 131, p. 184-195Article in journal (Refereed)
    Abstract [en]

    Iron is a key component of the chemical architecture of the biosphere. Due to the low bioavailability of iron in the environment, microorganisms have developed specific uptake strategies like production of siderophores. Siderophores are operationally defined as low-molecular-mass biogenic Fe(III)-binding compounds, that can increase the bioavailability of iron by promoting the dissolution of iron-bearing minerals. In the present study, we investigated the composition of dissolved and adsorbed siderophores of the hydroxamate family in the soil horizons of podzol and the effect of specific mineral types on siderophores. Three polished mineral specimens of 3 cm x 4 cm x 3 mm (apatite, biotite and oligioclase) were inserted in the soil horizons (O (organic), E (eluvial) and B (upper illuvial)). After two years, soil samples were collected from both the bulk soil of the whole profile and from the soil attached to the mineral surfaces. The concentration of ten different fungal tri-hydroxamates within ferrichromes, fusigen and coprogens families, and five bacterial hydroxamates within the ferrioxamine family were detected. All hydroxamate types were determined in both soil water (dissolved) and soil methanol (adsorbed) extracts along the whole soil profile by high-performance liquid chromatography coupled to electrospray ionization mass spectrometry (HPLC-ESI-MS); hence, the study is the most extensive of its kind. We found that coprogens and fusigen were present in much higher concentrations in bulk soil than were ferrioxamines and ferrichromes. On the other hand, the presence of the polished mineral completely altered the distribution of siderophores. In addition, each mineral had a unique interaction with the dissolved and adsorbed hydroxamates in the different soil horizons. Thus siderophore composition in the soil environment is controlled by the chemical, physical and biological characteristics of each soil horizon and also by the available mineral types.

  • 2090.
    Ahmed, Engy
    et al.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Hugerth, Luisa W.
    Logue, Jurg B.
    Brüchert, Volker
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Andersson, Anders F.
    Holmström, Sara J. M.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Mineral Type Structures Soil Microbial Communities2017In: Geomicrobiology Journal, ISSN 0149-0451, E-ISSN 1521-0529, Vol. 34, no 6, p. 538-545Article in journal (Refereed)
    Abstract [en]

    Soil microorganisms living in close contact with minerals play key roles in the biogeochemical cycling of elements, soil formation, and plant nutrition. Yet, the composition of microbial communities inhabiting the mineralosphere (i.e., the soil surrounding minerals) is poorly understood. Here, we explored the composition of soil microbial communities associated with different types of minerals in various soil horizons. To this effect, a field experiment was set up in which mineral specimens of apatite, biotite, and oligoclase were buried in the organic, eluvial, and upper illuvial horizons of a podzol soil. After an incubation period of two years, the soil attached to the mineral surfaces was collected, and microbial communities were analyzed by means of Illumina MiSeq sequencing of the 16S (prokaryotic) and 18S (eukaryotic) ribosomal RNA genes. We found that both composition and diversity of bacterial, archaeal, and fungal communities varied across the different mineral surfaces, and that mineral type had a greater influence on structuring microbial assemblages than soil horizon. Thus, our findings emphasize the importance of mineral surfaces as ecological niches in soils.

  • 2091.
    Ahmed, Engy
    et al.
    Stockholm University, Faculty of Science, Department of Geological Sciences. Stockholm University, Science for Life Laboratory (SciLifeLab).
    Parducci, Laura
    Unneberg, Per
    Ågren, Rasmus
    Schenk, Frederik
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Rattray, Jayne E.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Han, Lu
    Muschitiello, Francesco
    Stockholm University, Faculty of Science, Department of Geological Sciences. Columbia University, USA.
    Pedersen, Mikkel W.
    Smittenberg, Rienk H.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Afrifa Yamoah, Kweku
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Slotte, Tanja
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences. Stockholm University, Science for Life Laboratory (SciLifeLab).
    Wohlfarth, Barbara
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Archaeal community changes in Lateglacial lake sediments: Evidence from ancient DNA2018In: Quaternary Science Reviews, ISSN 0277-3791, E-ISSN 1873-457X, Vol. 181, p. 19-29Article in journal (Refereed)
    Abstract [en]

    The Lateglacial/early Holocene sediments from the ancient lake at Hasseldala Port, southern Sweden provide an important archive for the environmental and climatic shifts at the end of the last ice age and the transition into the present Interglacial. The existing multi-proxy data set highlights the complex interplay of physical and ecological changes in response to climatic shifts and lake status changes. Yet, it remains unclear how microorganisms, such as Archaea, which do not leave microscopic features in the sedimentary record, were affected by these climatic shifts. Here we present the metagenomic data set of Hasseldala Port with a special focus on the abundance and biodiversity of Archaea. This allows reconstructing for the first time the temporal succession of major Archaea groups between 13.9 and 10.8 ka BP by using ancient environmental DNA metagenomics and fossil archaeal cell membrane lipids. We then evaluate to which extent these findings reflect physical changes of the lake system, due to changes in lake-water summer temperature and seasonal lake-ice cover. We show that variations in archaeal composition and diversity were related to a variety of factors (e.g., changes in lake water temperature, duration of lake ice cover, rapid sediment infilling), which influenced bottom water conditions and the sediment-water interface. Methanogenic Archaea dominated during the Allerod and Younger Dryas pollen zones, when the ancient lake was likely stratified and anoxic for large parts of the year. The increase in archaeal diversity at the Younger Dryas/Holocene transition is explained by sediment infilling and formation of a mire/peatbog.

  • 2092.
    Ahmed, Ishtiaq
    Stockholm University, Faculty of Social Sciences, Department of Political Science.
    34 entries including on ideology, Islamic state, personalities, Muslim community, Islamic law and so on2012In: The Oxford Companion to Pakistani History / [ed] Ayesha Jalal, Karachi: Oxford University Press, 2012, , p. 558Chapter in book (Other academic)
  • 2093.
    Ahmed, Ishtiaq
    Stockholm University, Faculty of Social Sciences, Department of Political Science.
    Abdullahi An-Naim on Constitutional and Human Rights Issues1993In: Islamic Law Reform and Human Rights, Oslo: Nordic Human Rights Publications , 1993Chapter in book (Other academic)
  • 2094.
    Ahmed, Ishtiaq
    Stockholm University, Faculty of Social Sciences, Department of Political Science.
    Ethnicity abd Separatist Movements in South Asia1993In: Formation of Identity and Dynamics of Conflict in the 1990s, Göteborg: Nordnes , 1993Chapter in book (Other academic)
  • 2095.
    Ahmed, Ishtiaq
    Stockholm University, Faculty of Social Sciences, Department of Political Science.
    Exit, Voice and Citizenship1997In: International Migration, Immobility and Development: Multidisciplinary Perspectives, Oxford and New York: Berg Publishers , 1997Chapter in book (Other academic)
  • 2096.
    Ahmed, Ishtiaq
    Stockholm University, Faculty of Social Sciences.
    Globalisation and Human Rights in Pakistan2002In: Journal of Punjab Studies, Vol. 9, no 1, p. 57-89Article in journal (Refereed)
  • 2097.
    Ahmed, Ishtiaq
    Stockholm University, Faculty of Social Sciences, Department of Political Science.
    Group Representation in a Democracy?2007In: Utsikt mot utveckling: Equal Representation. A Challenge to Democracy and Democracy Promotion, no 29, p. 73-90Article in journal (Other academic)
  • 2098.
    Ahmed, Ishtiaq
    Stockholm University, Faculty of Social Sciences, Department of Political Science.
    Hamdard1995In: Encyclopedia of the Modern Islamic World, New York: Oxford University Press , 1995Chapter in book (Other academic)
  • 2099.
    Ahmed, Ishtiaq
    Stockholm University, Faculty of Social Sciences.
    Islam and Pan-Arabism in the Gulf Crisis1991Report (Other (popular science, discussion, etc.))
  • 2100.
    Ahmed, Ishtiaq
    Stockholm University, Faculty of Social Sciences.
    Looking backwards into the future: A Critique of Islamic Modernism2002In: Journal of Futures Studies, ISSN 1027-6084, Vol. 7, no 2, p. 75-96Article in journal (Refereed)
39404142434445 2051 - 2100 of 102027
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