1,429 research outputs found
Greenbelt Community Project: Solar energy retrofit for a multi-family dwelling
A cooperative project was initiated between Goddard Space Flight Center and the nearby community of Greenbelt, Maryland. The purpose was to design, install and operate an experimental solar heating system on a group of four tandem town houses. The system was successfully developed and is operating. A description is given of the design, installation, system operation and performance as well as the important considerations for judging the economic feasibility of solar heating systems
When Is Open Access Not Open Access?
As open access grows in prominence, so too has confusion about what open access means; such confusion arises from a genuine misunderstanding of open access by funders, authors, editors, and publishers alike
Grass-finished beef pilot project: Cattle performance and welfare
The study compared growth results for Angus cattle raised under feedlot conditions and under a grass-finishing regimen. Outcomes used to answer this question included growth and carcass characteristics, behavior and animal welfare parameters for weaned cattle that were raised using grain feeding or pasture management systems
An Analysis Of The Lyophilization Process Using A Sorptionāsublimation Model And Various Operational Policies
The freezeādrying process is studied under various operational policies through the use of a sorptionāsublimation model. The operational policy that provides the shortest drying times keeps the pressure at its lowest value. The upper and lower heating plates are independently controlled so that the material constraints are encountered and held throughout the free water removal phase. Under certain conditions, and for the case of samples of small thickness, the sorbed water profiles may have segments whose bound water concentrations are higher than those at the start of the free water removal phase. It is shown that the criterion used in terminating the freezeādrying process is of extreme importance, since it may lead to an undesirable sorbed water profile which may deteriorate the quality of the dried product. Copyright Ā© 1985 American Institute of Chemical Engineer
Developments in stem cell-derived islet replacement therapy for treating type 1 diabetes
The generation of islet-like endocrine clusters from human pluripotent stem cells (hPSCs) has the potential to provide an unlimited source of insulin-producing Ī² cells for the treatment of diabetes. In order for this cell therapy to become widely adopted, highly functional and well-characterized stem cell-derived islets (SC-islets) need to be manufactured at scale. Furthermore, successful SC-islet replacement strategies should prevent significant cell loss immediately following transplantation and avoid long-term immune rejection. This review highlights the most recent advances in the generation and characterization of highly functional SC-islets as well as strategies to ensure graft viability and safety after transplantation
āCatch 22ā: biosecurity awareness, interpretation and practice amongst poultry catchers
Campylobacter contamination of chicken on sale in the UK remains at high levels and has a substantial public health impact. This has prompted the application of many interventions in the supply chain, including enhanced biosecurity measures on-farm. Catching and thinning are acknowledged as threats to the maintenance of good biosecurity, yet the people employed to undertake this critical work (i.e. ācatchersā) are a rarely studied group. This study uses a mixed methods approach to investigate catchersā (nĀ =Ā 53) understanding of the biosecurity threats posed by the catching and thinning, and the barriers to good biosecurity practice. It interrogated the role of training in both the awareness and practice of good biosecurity. Awareness of lapses in biosecurity was assessed using a Watch-&-Click hazard awareness survey (nĀ =Ā 53). Qualitative interviews (nĀ =Ā 49 catchers, 5 farm managers) explored the understanding, experience and practice of catching and biosecurity. All of the catchers who took part in the Watch-&-Click study identified at least one of the biosecurity threats with 40% detecting all of the hazards. Those who had undergone training were significantly more likely to identify specific biosecurity threats and have a higher awareness score overall (48% compared to 9%, pĀ =Ā 0.03). Crucially, the individual and group interviews revealed the tensions between the high levels of biosecurity awareness evident from the survey and the reality of the routine practice of catching and thinning. Time pressures and a lack of equipment rather than a lack of knowledge appear a more fundamental cause of catcher-related biosecurity lapses. Our results reveal that catchers find themselves in a ācatch-22ā² situation in which mutually conflicting circumstances prevent simultaneous completion of their job and compliance with biosecurity standards
Boundedness and Stability of Impulsively Perturbed Systems in a Banach Space
Consider a linear impulsive equation in a Banach space
with . Suppose each solution of
the corresponding semi-homogeneous equation
(2) is bounded for any bounded sequence .
The conditions are determined ensuring
(a) the solution of the corresponding homogeneous equation has an exponential
estimate;
(b) each solution of (1),(2) is bounded on the half-line for any bounded
and bounded sequence ;
(c) for any tending to
zero;
(d) exponential estimate of implies a similar estimate for .Comment: 19 pages, LaTex-fil
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