9,709 research outputs found
Evaluation of the Water Quality Impacts of Land Application of Poultry Litter
Evaluating the effect of land application of animal waste on water quality is fraught with inherent variability due to differing infiltration rates, slope, rainfall intensity and etc . Simulated rainfall technology has been used in erosion research for decades. Generally, this technology is used on plots of sufficient size (25 x 5 m) to develop rill and interrill erosion. The object of this investigation was to adapt and modify existing rainfall simulation technology used in soil erosion research for use in evaluating water quality impacts of land application of animal waste, and to test, evaluate and demonstrate it\u27s scientific validity. State of the art simulation technology was obtained from the National Soil Erosion Research Laboratory located on the campus of Purdue University. The technology was scaled (2 x 6 m) and modified to fit into field research programs having several treatments and rep 1 i cated p 1 ots . The technology was shown to meet specification needed to produce the required raindrop size and velocity, flexibility in storm intensity, while maintaining uniformity(\u3e 0.8). Equally important, the unit is portable and fits well into labor intensive runoff work requiring replication of a variety of treatments
Preliminary feasibility study of a multi-Phobos encounter experiment during the Viking extended mission
The Viking '75 Mission to Mars is reported which permits a truly unique opportunity to explore the natural satellite, Phobos, from distances measured in tens of kilometers. A preliminary feasibility study has been made which shows that a science mission involving a Phobos close encounter is technically feasible and within the capabilities of the current Viking design. For less than 20 m/s, the Viking Orbiter can provide approximately two 40-day periods of close observation of Phobos, with the first encounter period in January and the second in March, 1977. Multi-pass images of the entire satellite from nearly all aspect angles and with resolution on the order of 10 meters are possible. Close encounters will permit mass determinations to an accuracy of tens of percent. These experiments can be performed in series with the nominal mission; thus, providing complementary scientific information without compromising the original mission and science objectives
STI policy and governance in Sub-Saharan Africa: Fostering actors’ interactions in research and innovation
This study investigates science, technology, and innovation (STI) policy and governance in relation to research and innovation (R&I) ecosystems in Sub-Saharan Africa (SSA). To understand the implications of STI policy and governance on R&I, the authors focus on university, industry and government actors; using the Triple Helix and National Systems of Innovation approaches as analytical frameworks to guide the study. The authors identify a range of factors hindering R&I actors’ interactions, including gaps in STI governance responsibilities and accountabilities, policymaking and structural transitions, R&I management capacity and capability gaps. Based on the findings, they propose changes to policymaking and the governance of R&I in SSA, in addition to advancing innovative approaches such as ‘resource circulation’ in the context of knowledge, research and science infrastructure scarcity. The findings provide fresh insights into STI policy and governance frameworks, fostering actors’ interactions and supporting performance improvements in research, science and innovation systems across Africa
Putting context into organizational intervention design:Using tailored questionnaires to measure initiatives for worker well-being
Realistic evaluation emphasizes the importance of exploring the mechanisms through which organizational interventions are effected. A well-known mechanism in organizational interventions is the screening process. Standardized questionnaires, in popular use, neither consider individuals’ appraisals of working conditions nor the specific context of the workplace. Screening with items tailored to intervention contexts may overcome the limitations of standardized questionnaires. In the present study, we evaluate an approach to develop a tailored questionnaire to measure employees’ appraisals of their specific working conditions. First, we interviewed 56 employees and 17 managers and, later, developed tailored items focused on the working conditions in a postal service. In follow-up interviews, we explore participants’ experiences with the tailored questionnaire, including the development of initiatives, compared to their previous experiences with the company´s annual attitude survey that used standardized scales. Results indicated that participants felt the tailored questionnaire highlighted issues that had previously been ignored, that initiatives were easier to develop due to its specificity, and that the feedback strategy was useful in prioritizing questionnaires. Overall, it can be concluded that tailored questionnaires may be appropriate for use in organizational intervention research and more broadly that evaluations of organizational interventions need to be contextually grounded
Shear-driven size segregation of granular materials: modeling and experiment
Granular materials segregate by size under shear, and the ability to
quantitatively predict the time required to achieve complete segregation is a
key test of our understanding of the segregation process. In this paper, we
apply the Gray-Thornton model of segregation (developed for linear shear
profiles) to a granular flow with an exponential profile, and evaluate its
ability to describe the observed segregation dynamics. Our experiment is
conducted in an annular Couette cell with a moving lower boundary. The granular
material is initially prepared in an unstable configuration with a layer of
small particles above a layer of large particles. Under shear, the sample mixes
and then re-segregates so that the large particles are located in the top half
of the system in the final state. During this segregation process, we measure
the velocity profile and use the resulting exponential fit as input parameters
to the model. To make a direct comparison between the continuum model and the
observed segregation dynamics, we locally map the measured height of the
experimental sample (which indicates the degree of segregation) to the local
packing density. We observe that the model successfully captures the presence
of a fast mixing process and relatively slower re-segregation process, but the
model predicts a finite re-segregation time, while in the experiment
re-segregation occurs only exponentially in time
Limitations in Predicting Radiation-Induced Pharmaceutical Instability during Long-Duration Spaceflight
As human spaceflight seeks to expand beyond low-Earth orbit, NASA and its
international partners face numerous challenges related to ensuring the safety
of their astronauts, including the need to provide a safe and effective
pharmacy for long-duration spaceflight. Historical missions have relied upon
frequent resupply of onboard pharmaceuticals; as a result, there has been
little study into the effects of long-term exposure of pharmaceuticals to the
space environment. Of particular concern are the long-term effects of space
radiation on drug stability, especially as missions venture away from the
protective proximity of the Earth. Here we highlight the risk of space
radiation to pharmaceuticals during exploration spaceflight, identifying the
limitations of current understanding. We further seek to identify ways in which
these limitations could be addressed through dedicated research efforts aimed
towards the rapid development of an effective pharmacy for future spaceflight
endeavors.Comment: in press, Nature Microgravit
Supporting early career health investigators in Kenya: A qualitative study of HIV/AIDS research capacity building
Introduction: strategies to transfer international health research training programs to sub-Saharan African institutions focus on developing cadresof local investigators who will lead such programs. Using a critical leadership theory framework, we conducted a qualitative study of one program to understand how collaborative training and research can support early career investigators in Kenya toward the program transfer goal.Methods: We used purposive sampling methods and a semi-structured protocol to conduct in-depth interviews with US (N=5) and Kenyan (N=5)independent investigators. Transcripts were coded using a two-step process, and then compared with each other to identify major themes.Results: A limited local research environment, funding needs and research career mentorship were identified as major influences on early career researchers. Institutional demands on Kenyan faculty to teach rather than complete research restricted investigators' ability to develop research careers. This was coupled with lack of local funding to support research. Sustainable collaborations between Kenyan, US and other international investigators were perceived to mitigate these challenges and support early career investigators who would help build a robust local research environment for training. Conclusion: mutually beneficial collaborations between Kenyan and US investigators developed during training mitigate these challenges and build a supportive research environment for training. In these collaborations, early career investigators learn how to navigate the complex international research environment to build local HIV research capacity.Shared and mutually beneficial resources within international research collaborations are required to support early career investigators and plans to transfer health research training to African institutions
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