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  • 1.
    Benson, Livia
    Stockholm University, Faculty of Science, Department of Biology Education.
    Social and political aspects of urban ecology: Possibilities and constraints for civic actors to influence urban green area planning at Årstafältet, Stockholm2009Independent thesis Basic level (university diploma), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Answers to fundamental questions about pattern and process in the ecological and human world often comes from within the boundaries of one discipline or another, neglecting the relationships between the ecological and social systems. One manifestation of these relationships, which also forms the focus of this study, is conflicts over how to use urban green areas. Various scholars imply that civil society organisations and individual citizens can play an important role in articulating the ecological and social values that exist in much disputed green areas, and can therefore create a “protective story” to prevent exploitation. Following these implications and using a social network or social capital perspective, this study investigates a current conflict concerning Årstafältet, or the Årsta field, in Stockholm, which is suggested for exploitation, and focuses on the civic actors’ ability to participate in influencing the future of this green area. Although the conflict is still ongoing, the actors in the case study have at the present stage not been successful in protecting their green area. The results from interviews and participatory observations show the importance of accessing useful artefacts to incorporate into a protective story, and being able to present the artefacts in appropriate social arenas something that has been a limitation for the actors of Årstafältet. The actor groups’ ability to balance bridging and bonding social capital is also a factor that can have affected their success. The study further reveals a lack of democracy in the decision making process and suggest that public actors impede the participation of civic actors in contributing in the planning of urban green areas rather than facilitate their participation. In addition to highlighting some of the social and political factors that affect the emergence of green spatial structures in urban landscapes this study also establishes that the ecological perspective has been neglected in the case of Årstafältet. Following the results of the study a contemporary approach of studying urban ecology which includes attention on the mixture of social, political and ecological perspectives is encouraged for future research.

  • 2.
    Hasnat, Md. Abul
    Stockholm University, Faculty of Science, Department of Biology Education. Sher-e-Bangla Agricultural University, Bangladesh.
    Reproductive Potential Difference of Artificially Inseminated and Naturally Mated Honey Bee Queens (Apis mellifera L.)2018Independent thesis Advanced level (degree of Master (Two Years)), 40 credits / 60 HE creditsStudent thesis
    Abstract [en]

    Apis mellifera L. is the only commercially cultivated bee species in Bangladesh nowadays and has been practicing for migratory beekeeping since 1990. Notably, without taking initiatives to improve the bee stocks, intensified beekeeping has been making the species vulnerable to different threats of diseases, pests and inbreeding depression. Reproductive potentiality of the queens has been declining severely. The investigation was carried out to diagnose present problems regarding reproductive potentiality of the queen bees and finding out the possible solutions. Firstly, 56 numbers of naturally mated queens (Apis mellifera L.) were collected from problematic and non-problematic hives from three districts of Bangladesh. Samples were weighed, body length and thorax width were measured, and dissected to study spermathecae appearance. Average queen body weight (160.75±3.65 mg) was found much lower than the earlier studies in different countries. Moreover, 32.33% spermathecae of the queens were found poor in appearance. Again, 3 different queen rearing and mating procedures were applied in 12 replications each: naturally mated queen (NM), grafted and naturally mated queen (GNM) and grafted and artificially inseminated queen (AIQ). NM and GNM queens were allowed to mate naturally where AIQ queens were inseminated artificially in the laboratory. Interestingly, GNM (196.65±3.13 mg) and AIQ(196.55±2.41 mg) queens were significantly heavier than the NM (159.07±6.94 mg) queens. Likewise, their spermathecae radius, respective workers, drones, brood occupation area showed much better strength than the NM queens, though, latency period of AIQ queens were higher. Since grafted queens were reared with good larvae and implemented in artificial queen cups with increased brood support, hence that could make the queens heavier and reproductively more potential, whereas NM queens were left to grow naturally and found less potential. The findings will encourage beekeepers for practicing grafting procedure as the better queen rearing procedure in field condition. However, the procedure of AIQ queens also could be used for stock improvement and bee research because of its control mating system.

  • 3.
    Plowey, Matthew
    Stockholm University, Faculty of Science, Department of Biology Education. Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    A multi-scale approach to monitoring the optically complex coastal waters of the Baltic Sea: A comparison of satellite, mooring, and ship-based monitoring of water quality2019Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    This study was designed to examine the spatial and temporal capabilities of ESA’s OLCI on the Sentinel-3A platform to monitor the water quality parameters: chlorophyll-a, turbidity, and CDOM in the Baltic Sea when compared to more traditional monitoring techniques such as monitoring by ship or mooring. The measurement frequency of OLCI/Sentinel-3A data is also compared to the frequency of MERIS/ENVISAT data (from 2008 and 2010).

     

    OLCI S3A full resolution level 2 data from 2017 and 2018 of the NW Baltic proper’s coastal region was processed to remove pixels of low data quality using predetermined flags. The number of valid scenes per year was determined and the level 2 products: chlorophyll-a (chl_NN), turbidity (derived from TSM_NN), and CDOM (using ADG_443_NN as a proxy) were calculated by averaging the values of 9 pixels surrounding, and including, a central sampling site.  These measurements were then compared to paired in situ measurements, taken on the same day +/- 3 hours of satellite overpass, to examine the correspondence and variability between measurements. Measurements from a WetLabs WQM mooring were also examined and compared to in situ measurements. Pearson’s correlation was used to determine covariance between OLCI S3A’s measurements and in situ measurements and mean normalized bias, root mean square error, and mean absolute percentage difference were used to evaluate the performance of OLCI S3A and the optical mooring compared to in situ measurements.

     

    OLCI S3A produced a higher number of valid observations per month than its predecessor MERIS for both stations: B1 and BY31.  It also produced more valid observations per month at stations B1 and BY31 than ship-based monitoring teams. OLCI S3A’s current method of processing underestimated chlorophyll-a concentrations (MNB = -7%, RMSE = 40%, APD = 49%, r = 0.48, p < .00001, N = 156) especially if chlorophyll-a concentrations were measured during peak production periods. The optical mooring showed a much higher correlation but more relative error and bias (MNB = -39%, RMSE = 43%, APD = 39%, r = 0.94, p < 0.00001, N = 12) also underestimating chlorophyll-a concentrations.  OLCI S3A’s current ocean color processing method drastically overestimates turbidity (MNB = 189%, RMSE = 1011%, APD = 214%, r = 0.55, p = .000097, N = 45) whereas the optical mooring showed good agreement with in situ measurements and less variability (MNB = 21%, RMSE = 26%, APD = 21%, r = 0.69, p = 0.0132, N = 17). Lastly, OLCI S3A was strongly correlated to in situ CDOM values (MNB = -5%, RMSE = 37%, APD = 51%, r = 0.82, p < 0.00001, N = 36).

     

    Overall, OLCI shows improved retrieval of chl-a at values below 10 mgl-1  as well as improved CDOM retrieval than MERIS (underestimation of about 40% vs. about 60-75%). Turbidity is highly overestimated, but can be corrected either using in situ data for calibration, or by applying the regional TSM-specific scatter before converting to turbidity. 

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