1,007 research outputs found
Corolla size and temporal displacement of flowering times among sympatric diploid and tetraploid highbush blueberry (Vaccinium corymbosum)
No full textPolyploidy (whole-genome duplication) is common in vascular plants, but the modes of establishment and persistence, as well as the ecological consequences, of polyploidy remain vague. Highbush blueberry (Vaccinium corymbosum L.) is an ecologically and economically important understory shrub with an unclear species definition, coexisting in sympatric populations of diploid and tetraploid cytotypes. This study analyzes differences in bloom time between sympatric diploid and tetraploid V. corymbosum in natural populations, testing the potential for these cytotypes to interbreed and contributing to the formation and continuity of ploidy-level diversification within this species. Ploidal level was confirmed through DNA flow cytometry of sympatric plants from two populations in New Jersey, USA. Flower bloom date and corolla size were recorded over a three-year period. Diploid corollas were 32% smaller than tetraploid corollas, making them easily identifiable in the field. Ploidy accounted for 55-69% of the variation in bloom date, with diploids flowering about one week before tetraploids, and the remaining variation distributed among plants, among branches, and within branches. Notwithstanding these differences, there was modest overlap in flowering time between cytotypes, suggesting that cross-pollination is possible. This contributes evidence to the most current species definition of V. corymbosum as a single (mixed ploidy) species.Poster's Graduate Student Thesis Publication.Peer reviewed
Prospects for equitable growth in rural sub-Saharan Africa
No full textImproving agricultural technology equitably in Africa has been difficult in the past because of the vast differences, as well as weak institutions and infrastructure in its many regions. However, the prospects for equitable growth are good for several reasons. The distribution of land has not deteriorated, and there are few landless people in Africa. Technical packages do not favor large farms over small ones, and Africa's social institutions support people with a safety net for sources of income. The author, however, points out that equitable growth, though possible is not assured and several research and policy initiatives will be needed to capitalize on the potential. First, research must continue to focus on technology appropriate for small farms and crops. Policy makers must no longer withhold assistance from service enterprises or nonfarm activities of women. Rural infrastructure has to be upgraded, and finally, governments will need to monitor land tenure and tenancy.Economic Theory&Research,Agricultural Research,Crops&Crop Management Systems,Environmental Economics&Policies,Agricultural Knowledge&Information Systems
Developing and implementing a policy for consensual sex between inpatients
No full textThe chapter, "Developing and implementing a policy for consensual sex between inpatients" was written by the listed authors including Steven Welch (Douglas College Faculty).Part of the "Chronic Mental Illness" series (Volume 7).Sexuality and Serious Mental Illness is the first book to draw together the collective wisdom and experience of clinicians, advocates, consumers, researchers, legal experts and administrators. The research reflects a current understanding of the complexities of sexual activity among persons with chronic mental illness in a variety of settings. Sexuality and Serious Mental Illness is particularly timely in view of recent emphases on patient choice, recovery and advocacy, and can be used to provide guidance to clinicians, mental health administrators, policymakers, advocates and researchers. --From publisher description.Published
Provenance-based trust for grid computing: Position Paper
No full textCurrent evolutions of Internet technology such as Web Services, ebXML, peer-to-peer and Grid computing all point to the development of large-scale open networks of diverse computing systems interacting with one another to perform tasks. Grid systems (and Web Services) are exemplary in this respect and are perhaps some of the first large-scale open computing systems to see widespread use - making them an important testing ground for problems in trust management which are likely to arise. From this perspective, today's grid architectures suffer from limitations, such as lack of a mechanism to trace results and lack of infrastructure to build up trust networks. These are important concerns in open grids, in which "community resources" are owned and managed by multiple stakeholders, and are dynamically organised in virtual organisations. Provenance enables users to trace how a particular result has been arrived at by identifying the individual services and the aggregation of services that produced such a particular output. Against this background, we present a research agenda to design, conceive and implement an industrial-strength open provenance architecture for grid systems. We motivate its use with three complex grid applications, namely aerospace engineering, organ transplant management and bioinformatics. Industrial-strength provenance support includes a scalable and secure architecture, an open proposal for standardising the protocols and data structures, a set of tools for configuring and using the provenance architecture, an open source reference implementation, and a deployment and validation in industrial context. The provision of such facilities will enrich grid capabilities by including new functionalities required for solving complex problems such as provenance data to provide complete audit trails of process execution and third-party analysis and auditing. As a result, we anticipate that a larger uptake of grid technology is likely to occur, since unprecedented possibilities will be offered to users and will give them a competitive edge
Correction for Millership et al., Increased lipolysis and altered lipid homeostasis protect -synuclein-null mutant mice from diet-induced obesity
No full textCorrection for “Increased lipolysis and altered lipid homeostasis protect γ-synuclein–null mutant mice from diet-induced obesity,” by Steven Millership, Natalia Ninkina, Irina A. Guschina, Jessica Norton, Ricardo Brambilla, Pieter J. Oort, Sean H. Adams, Rowena J. Dennis, Peter J. Voshol, Justin J. Rochford, and Vladimir L. Buchman, which appeared in issue 51, December 18, 2012, of Proc Natl Acad Sci USA (109:20943–20948; first published December 3, 2012; 10.1073/pnas.1210022110). The authors note that the author name Ricardo Brambilla should instead appear as Riccardo Brambilla. The corrected author line appears below. The online version has been corrected
Responses in E. coli to combinatorial stress treatments (HCl, EDTA, H2O2, and CuSO4):
No full textAll living organisms adapt to their environment through a series of biochemical responses. Escherichia coli (E. coli) have a plethora of different enzymes, sigma factors, and other biomolecules that assist in stress relief. These experiments showed that E. coli have stress responses for individual stresses. These stress responses are not always additive when exposed to multiple stress factors.
Many times an individual stress response is triggered to counteract a single environmental change. Sometimes this same stress response will aid the cells with a different, unrelated stress. When both stresses are present, more of this stress response will materialize as a response to both stresses and will help prevent too much damage to the cell. This is called "cross-protection" of stress. After seeing the results of these experiments, it is believed that E. coli has some global stress responses and many of the biomolecules used to fight stress are involved in cross-protection of multiple stresses.
These results were generated using a method where E. coli were grown onto control agar plates as well as plates treated with small concentrations of lethal substances. Using a technique called "Blue/White Screening" and colony counting software, the amount of colonies grown overnight on these plates could be counted. The area of the colonies and the relative amount of β-galactosidase transcribed and translated could also be measured. The control plates and treated plates were compared using these three criteria. The different individual stresses were also compared.
Plates were also treated with combinations of the same stresses and compared to the single treatment plates. Much of the data collected indicated a difference in E. coli's responses to an individual stress and how E. coli would be expected to react if the stress responses were additive. This proves that there was some cross-protection taking place in some instances.
Changes in distributions were also examined for each set of plates in order to examine the effect of the stresses on the stochastic nature of E. coli growth and functional protein production. Differences were noticed when comparing the distributions of control plates and stress plates. Differences were seen in different types and combinatorial stressors as well.
The second half of the experiments done here focused on using high performance liquid chromatography to find differences in concentration of molecules in E. coli extracts that were treated with hydrogen peroxide for a brief amount of time and control E. coli extracts not put under any stress. This experiment proved to be too inconsistent to learn any facts. There was an issue with the chemistry involved in the E. coli extracts reactions with the indicator molecules used to find free thiols and free amines in the extracts.M.S.Includes bibliographical references (p. 171-184)by Steven Middle
Is the debt crisis history? Recent private capital inflows to developing countries
No full textThe outlook for economic development for an important group of middle-income countries has again been buoyed by substantial private capital inflows in the 1990s. As in the 1970s, this development has been met with cautious optimism. It is generally accepted that these countries need resource transfers from the rest of the world to support capital formation and growth. It is also generally accepted that these private capital flows make the allocation of resources more efficient. But there is concern that a rapid reversal of market sentiment could impose considerable adjustment costs on these same economies. The authors try to quantify what many consider to be the main reasons debtor countries have access to capital markets again: (a) Domestic policy reform in the debtor countries. (b) Debt and debt service reduction, usually associated with Brady Plan restructuring. (c) Changes in the external market, such as changes in interest rates in industrial countries. They argue that a useful barometer for access to new loans is the market value of existing sovereign debt. It follows that a quantitative analysis of the factors that caused the market value of sovereign debts to rise rapidly after 1989 would also improve understanding of the forces behind the renewed access to international capital. Empirical historical evidence suggests that fiscal reform, privatization, and debt reduction are useful in explaining relative improvements in the standing of debtor countries in international credit markets. Debtor countries with strong reform programs, in other words, are better prepared to withstand deterioration in the external environment. But the reduction in dollar interest rates since 1989 appears to be the chief factor in the debtor countries'renewed access to international loans. The authors estimate the effect of increases in dollar interest rates and conclude that the typical debtor country remains vulnerable to increases in interest rates that are well within the range of recent experience.Economic Theory&Research,Environmental Economics&Policies,Banks&Banking Reform,Strategic Debt Management,Financial Intermediation
Optimum time to refurbish a boiler feed pump at Eskom's power stations
No full textA key focus area in power generation today is to improve equipment and plant efficiency, with this study specifically aimed to determine the optimum time to refurbish a boiler feed pump by analysing the internal wear of the annular seals. The boiler feed pump (BFP) installed in a power station is either driven by a steam turbine or an electric motor and the BFP is the highest auxiliary power consumer within the power station. In the 13 Eskom generating fossil fired power stations the installed BFPs consume approximately 1000 MWs of auxiliary power continuously. The focus of the study is to understand how the BFPs efficiency changes with time as a result of increased internal clearances and the effect this has on the auxiliary power consumption. An in-depth analysis of the efficiency degradation has been studied to understand the contributing factors to these changes and specifically the change in leakage rate and friction in the annular seals of the impellers and axial thrust balancing devices
Politics of cross-cultural reading : three case studies (Rabindranath Tagore, Tahar Ben Jelloun and Dario Fo)
No full textTHESIS 9844The aim of this thesis is to develop a multifaceted model by which one can engage with cross-cultural acts of reading in a meaningful way and to provide a sample of quite diverse works of world literature in translation to show the model?s flexibility. My methodology combines reception studies (Wolfgang Iser, Hans-Robert Jauss and Peter Rabinowitz) with polysystem theory (Itamar Even-Zohar) and rhetorical hermeneutics (Steven Mailloux). The foundations of meaning are negotiated in a complex interpretive process that involves an act of sense making (understanding) and an act of making-sense-to-others (persuading). Like meaning, authority and authenticity do not reside at one site (?the original? or ?the author?) but are distributed among various agents participating in the production and positioning of a literary text. The model developed in chapters 1 and 2 takes into account the text?s location in its producing culture and the agents? location in theirs
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