The City of Johannesburg is facing the simultaneous challenges of an increased generation of solid waste in the City, unemployment and the running out of land to dispose the waste. Of the solid waste that is generated, 50% is recyclable while only 10% is recycled (SOER, 2003: 69). Solid waste recycling is mainly performed through private sector initiatives in the City of Johannesburg. Consequently, there is no proper coordination with government initiatives. In order for South Africa to increase and sustain economic growth that would decrease unemployment, there should be a culture of entrepreneurship (Mass, G & Herrington M, 2006:7). Solid waste buy-back centres assist in addressing the challenges of dealing with the increased generation of solid waste and the scarcity of land for disposal. These centres also reduce the challenges of unemployment through promoting entrepreneurs to operate solid waste recycling businesses. Developed economies have managed to increase the rate of solid waste recycling to 60%. The problems associated with solid waste have been reduced by promoting recycling through a combination of legislation and setting-up of agencies to deal with solid waste recycling. South Africa has legislation and stated programmes to deal with solid waste recycling. Nevertheless, there has been complexity with implementing recycling. This is the result of a lack of co-ordination between the role-players involved in the value chain of solid waste recycling. In order for the City of Johannesburg to increase the recycling of solid waste from 10% to optimal rates of between 50% and 60%, there should be co-ordination of programmes amongst all the role players. In addition, there should also be skills provision to existing and potential entrepreneurs operating the solid waste buy-back centres. All spheres of government should promote solid waste recycling business to potential entrepreneurs and the public in order to recycle 40% of the recyclable solid waste that is not being recycled. The establishment of a solid waste buy-back centre in the City of Johannesburg is economically viable with some buy-back centre realising a net-profit of least R5 000 and some more than R30 000 per month. In order for the solid waste buy-back centre to realise a net-profit of more than R30 000 per month, there must be more than 40 tons of recyclable solid waste received by the buy-back centre per month. This study has indicated that solid waste buy-back centres rely on the economies of scale. This means that the more recyclable solid waste is received and sold by the solid waste buy-back centres, the more profitable it becomes. / Thesis (M.B.A.)--North-West University, Vaal Triangle Campus, 2009.

The City of Johannesburg is facing the simultaneous challenges of an increased generation of solid waste in the City, unemployment and the running out of land to dispose the waste. Of the solid waste that is generated, 50% is recyclable while only 10% is recycled (SOER, 2003: 69). Solid waste recycling is mainly performed through private sector initiatives in the City of Johannesburg. Consequently, there is no proper coordination with government initiatives. In order for South Africa to increase and sustain economic growth that would decrease unemployment, there should be a culture of entrepreneurship (Mass, G & Herrington M, 2006:7). Solid waste buy-back centres assist in addressing the challenges of dealing with the increased generation of solid waste and the scarcity of land for disposal. These centres also reduce the challenges of unemployment through promoting entrepreneurs to operate solid waste recycling businesses. Developed economies have managed to increase the rate of solid waste recycling to 60%. The problems associated with solid waste have been reduced by promoting recycling through a combination of legislation and setting-up of agencies to deal with solid waste recycling. South Africa has legislation and stated programmes to deal with solid waste recycling. Nevertheless, there has been complexity with implementing recycling. This is the result of a lack of co-ordination between the role-players involved in the value chain of solid waste recycling. In order for the City of Johannesburg to increase the recycling of solid waste from 10% to optimal rates of between 50% and 60%, there should be co-ordination of programmes amongst all the role players. In addition, there should also be skills provision to existing and potential entrepreneurs operating the solid waste buy-back centres. All spheres of government should promote solid waste recycling business to potential entrepreneurs and the public in order to recycle 40% of the recyclable solid waste that is not being recycled. The establishment of a solid waste buy-back centre in the City of Johannesburg is economically viable with some buy-back centre realising a net-profit of least R5 000 and some more than R30 000 per month. In order for the solid waste buy-back centre to realise a net-profit of more than R30 000 per month, there must be more than 40 tons of recyclable solid waste received by the buy-back centre per month. This study has indicated that solid waste buy-back centres rely on the economies of scale. This means that the more recyclable solid waste is received and sold by the solid waste buy-back centres, the more profitable it becomes. / Thesis (M.B.A.)--North-West University, Vaal Triangle Campus, 2009.

Bibliography: leaves 155-182. / xiv, 182, [10] leaves, [11] leaves of plates : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Most agricultural crop seeds are 'orthodox' ie. desiccation is a necessary feature of their complete life cycle. Low moisture content lengthens the storage life of orthodox seeds. Recalcitrant seeds, which do not tolerate low moisture content, lose viability in dry storage. The thesis studies the role of sugars in desiccation tolerance in developing seeds and investigates other mechanisms which might be involved in desiccation tolerance and desiccation sensitivity. / Thesis (Ph.D.)--University of Adelaide, Dept. of Plant Science, 1996?

The overall aim of the study was to assess the risk of gene flow from Brassica crops by insectmediated pollen transport. I measured the viability of pollen in Brassica flowers throughout crop development and compared this with the viability of pollen transported by insects inside and outside one early- and one late-season crop. In order to evaluate the relative importance of different species in pollen transport, I measured abundance of flower visitors during crop development, and measured the foraging behaviour of five key pollinator species throughout the growing season, in relation to variation in microclimate, crop phenology and the relative abundance of other pollinator species competing for flower resources. Flower visiting insects of Brassica rapa crops were highly diverse, and their abundance and diversity changed with crop phenology. I found similar abundances at the family level for both crops studied, although capture rates were greater in the early- than in the late-season crop. Across flowering development, the greatest numbers of insects were captured at the peak of flowering for both crops. During the flowering period, Diptera was the most abundant order collected, followed by Hymenoptera. The most abundant family in Hymenoptera was Apidae which tracked crop development in both fields, with greater numbers of insects captured inside than outside the field. Standardized-count pollen loads were smaller in Diptera than in Hymenoptera. Of the five key pollinator species sampled, Lasioglossum sordidum (Hymenoptera: Halictidae), Apis mellifera (Hymenoptera: Apidae) and Bombus terrestris (Hymenoptera: Apidae) transported similar pollen loads, which were much greater than those carried by Eristalis tenax (Diptera: Syrphidae) and Melangyna novae-zealandiae (Diptera: Syrphidae). The numbers of insects captured outside of the crop were 10% and 33% of the totals captured inside for the early- and the late-season crop, respectively. The proportion of insects entering versus leaving the crop varied considerably across species, crops and trap location (i.e., whether traps were inside or 50 m outside the border of the crop). However, it is worth noting that not uncommonly more insects were attracted into the crop early in the season, staying there rather than leaving, and then when flowers started to disappear there was a massive escape of insects leaving. This research provides evidence for the influence of crop age on the foraging behaviour of key pollinators and for species-specific variation in the foraging behaviour of Brassica visitors with crop development. Temporal variation in the rate and variability of movement between flowers, and the duration and variability in time spent on each flower, throughout the growing season differed markedly between pollinator species. Flower density, plant density, and the abundance of other insects contributed to the observed variation in pollinator behavioural activity for A. mellifera, E. tenax, M. novae-zelandiae and L. sordidum. Bombus terrestris had the greatest rates and variability of movement, and the greatest rates of flower visitation among all key pollinators studied. Therefore B. terrestris might contribute to gene flow to a greater extent than other key pollinators. Additionally B. terrestris had the greatest variability in the rate of movement, increasing the risk of pollen movement over long distances. In summary, I found that (i) insect abundance and diversity changed with crop phenology and Diptera was the most abundant order collected, (ii) flower density, plant density, and the abundance of other insect pollinators were important factors explaining pollinator behaviour for all key pollinators, except B. terrestris, (iii) B. terrestris might contribute to gene flow to a greater extent than other key pollinators, because it has a greater rate of flower visitation and a greater flight distance between flowers than other pollinators, and (iv) pollen viability tended to decrease with crop development and declined sharply even just 50 m outside the edge of the crop.

Thesis (M.Sc. Biological Sciences)--University of Waikato, 2007. / Title from PDF cover (viewed April 7, 2008) Includes bibliographical references (p. 91-101)

Thesis (M.Sc.) Uppsala : Sveriges lantbruksuniv.

abstract: The southwestern willow flycatcher (Empidonax traillii extimus) is listed as an endangered species throughout its range in the southwestern United States. Little is known about its sub-population spatial structure and how this impacts its population viability. In conjunction with being listed as endangered, a recovery plan was produced by the US Fish and Wildlife Service, with recovery units (sub-populations) roughly based on major river drainages. In the interest of examining this configuration of sub-populations and their impact on the measured population viability, I applied a multivariate auto-regressive state-space model to a spatially extensive time series of abundance data for the southwestern willow flycatcher over the period spanning 1995-2010 estimating critical growth parameters, correlation in environmental stochasticity or "synchronicity" between sub-populations (recovery units) and extinction risk of the sub-populations and the whole. The model estimates two parameters, the mean and variance of annual growth rate. Of the models I tested, I found the strongest support for a population model in which three of the recovery units were grouped (the Lower Colorado, Gila Basin, and Rio Grande recovery units) while keeping all others separate. This configuration has 6.6 times more support for the observed data than a configuration assigning each recovery unit to a separate sub-population, which is how they are circumscribed in the recovery plan. Given the best model, the mean growth rate is -0.0234 (CI95 -0.0939, 0.0412) with a variance of 0.0597 (CI95 0.0115, 0.1134). This growth rate is not significantly different from zero and this is reflected in the low potential for quasi-extinction. The cumulative probability of the population experiencing at least an 80% decline from current levels within 15 years for some sub-populations were much higher (range: 0.129-0.396 for an 80% decline). These results suggest that the rangewide population has a low risk of extinction in the next 15 years and that the formal recovery units specified by the original recovery plan do not correspond to proper sub-population units as defined by population synchrony. / Dissertation/Thesis / M.S. Biology 2012

Orientador: José Antônio Dell'aqua Junior / Resumo: Tem sido relatado que altas concentrações de osteopontina (OPN) no plasma seminal de diversar espécies esta correlacionada com animais de alta fertilidade, identificando-a como bio marcador reprodutivo. De igual maneira estudos mostram uma maior taxa de fertilização in vitro quando é implementada nos meios para fertilização. Visto que a OPN pode ter funções antagônicas, o presente estudo visou identificar se suas funções são dose dependente, adicionando 4 diferentes concentrações de OPN sobre o sêmen sexado bovino por 30 minutos e avaliar por (i) citometria de fluxo a viabilidade, integridade de membrana e capacitação espermática; (ii) teste de ligação a células epiteliais da tuba uterina bovina (BOECs), para quantificar o numero de espermatozoides ligados às células epiteliais, formando o que seria in vivo o reservatório espermático e (iii) avaliar a produção de embriões in vitro. Na avaliação por citometria não foi observada uma interação da adição de OPN com os espermatozoides sexados e não sexados, diferente dos outros dois testes onde se evidenciou que independente da dose a OPN diminuiu a ligação dos espermatozoides às BOECs e a concentração de 0.5g/1x106 espermatozoides aumento a taxa de clivagem e formação de blastocistos. Isto ratifica o poder capacitante da OPN de 60KDa sobre os espermatozoides e confirma que esta, pode ter associações diretas com ambos gametos, gerando melhores taxas de fertilização in vitro e, por tanto, melhor desenvolvimento embrionário nos bovi... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: It has been reported that high concentrations of osteopontin (OPN) in the seminal plasma of diverse species is correlated with high fertility animals, identifying it as a bio-reproductive marker. Likewise studies show a higher rate of in vitro fertilization when it´s implemented in fertilization media. Since OPN may have antagonistic functions, the present study aimed to identify if its functions are dose-dependent, adding four different concentrations of OPN on the sex-sorted and non-sorted bovine sperm for 30 minutes. The samples were evaluated by means of (i) flow cytometry the viability, membrane integrity and sperm capacitation; (ii) sperm-binding assay to BOECs, to quantify the number of sperm attached to the epithelial cells, forming what would be in vivo the spermatic reservoir and (iii) to evaluate the in vitro embryo production. In flow cytometry an interaction of the addition of OPN with the sex-sorted and non-sorted sperm was not observed, different from the other two tests where it was evidenced that regardless of the dose, the OPN decreased the sperm binding to the BOECs and the concentration of 0.5 µg /1 x 106 spermatozoa increased the rate of cleavage and formation of blastocysts. This corroborates the capacitive power of the OPN of 60KDa on the spermatozoa, and confirm that it can have direct associations with both gametes, generating better rates of in vitro fertilization and, therefore, better embryonic development in cattle. However, from the results obtai... (Complete abstract click electronic access below) / Doutor

Este trabalho objetivou analisar os benefícios econômicos gerados pelos sistemas de produção agropecuária mistos, e também, avaliar o resultado econômico do sistema de integração lavoura-pecuária em Tangará da Serra, sudoeste do Estado de Mato Grosso. Na primeira etapa, foi realizada uma revisão sistemática com artigos internacionais que obtiveram a análise do resultado econômico em sistemas de produção mistos em 16 países. Na segunda etapa, utilizou-se um modelo determinístico para avaliar a viabilidade econômica do sistema de agricultura convencional (Sistema I) versus o sistema de integração lavoura-pecuária (Sistema II) no sudoeste de Mato Grosso. Ainda, aplicou-se um modelo estocástico para analisar o risco dos Sistema I e II. Os resultados obtidos comprovaram a mitigação do risco econômico quando utiliza-se sistemas de produção mistos, como a integração lavoura-pecuária. Porém, indicam que as principais limitações para a expansão desse sistema é a exigência de fatores de produção e a gestão na empresa rural. / This study aimed to analyze the economic benefits generated by mixed agricultural production systems and also to evaluate the economic results of integrated crop-livestock system in Tangara da Serra, southwest of Mato Grosso State. In the first step, a systematic review was performed with international articles that have achieved the economic analysis results in mixed production systems in 16 countries. In the second stage, we used a deterministic model to evaluate the economic viability of the conventional farming system (System I) versus the integrated crop-livestock system (System II) in the southwest of Mato Grosso. Still, it was applied a stochastic model for analyzing the risk of system I and II. The results proved the mitigation of economic risk when used mixed farming systems, such as integrated crop-livestock. However, indicate that the main constraints to the expansion of this system is the requirement for factors of production and management in rural business.

Swamp rabbits (Sylvilagus aquaticus) in southern Illinois exist as a metapopulation due to loss and fragmentation of the bottomland hardwood forests in which they live, making their persistence in the state uncertain. I ran a spatially-explicit population viability analysis (PVA) on the metapopulation, using a habitat suitability map I created and life history parameters drawn from the literature. I varied parameters related to reproduction, survival, catastrophes, dispersal, and carrying capacity from 50 to 150% of the initial value of each parameter to compare their effects on extinction risk. I modified the map to test the effects of potential habitat loss, fragmentation, and the addition of dispersal corridors on the swamp rabbit metapopulation in southern Illinois. Under baseline conditions, the model suggested about a 20% chance of quasi-extinction (90% metapopulation decline) in 25 years. Changes in fecundity values and the effects of catastrophic flooding had the greatest effect on the risk of extinction, causing quasi-extinction probabilities to range from 0 to 100% and 0 to 87%, respectively. In contrast, changing dispersal values yielded the least impact on the risk of extinction (18-24%), and all other parameters had moderate impacts on the model. Removing groups of the largest habitat patches increased the risk of extinction, whereas removing groups of the smallest habitat patches decreased the risk of extinction, suggesting that small patches could act as population sinks with a negative impact on swamp rabbit persistence. Decreasing patch fragmentation per se reduced the risk of extinction slightly. The addition of dispersal corridors made no significant impact on the probability of extinction. My findings indicate that more research estimating fecundity and the effect of catastrophic floods on swamp rabbits in Illinois is required to more accurately predict swamp rabbit persistence in the state. I also suggest that managers should work to decrease the effect of flooding on the population by improving upland habitat, or decrease fragmentation by increasing the area of bottomland hardwood forests around existing habitat patches. Lastly, I suggest managers focus on preventing further habitat fragmentation into small patches, which will mitigate the creation of potential sink populations and will enable current populations to persist.