290 research outputs found
Oocyte size, egg index, and body lipid content in relation to body size in the solitary bee Megachile rotundata
Females of solitary, nest-provisioning bees have relatively low fecundity, but produce large eggs as part of their overall strategy of investing substantially in each offspring. In intraspecific comparisons of several species of solitary, nest-provisioning bees and wasps, the size of the mature eggs produced increases with female body size. We further examined oocyte sizeābody size correlations in the solitary bee Megachile rotundata (F.), an important crop pollinator. We hypothesized that larger females carry larger basal oocytes (i.e., those next in line to be oviposited) but that body sizeāoocyte size correlations would be absent soon after emergence, before their first eggs fully matured. Because egg production is likely affected by the quantity of stored lipids carried over from the beesā immature stages, we also tested the hypothesis that female body size is correlated with the body lipid content at adult emergence, the time during which oocyte growth accelerates. We found significant correlations of body size with oocyte size variables chosen to reflect: (1) the magnitude of the investment in the next egg to be laid (i.e., the length and volume of the basal oocyte) and (2) the longer term potential to produce mature oocytes (i.e., the summed lengths and volumes of the three largest oocytes in each female). Positive correlations existed throughout the nesting season, even during the first week following adult emergence. The ability to produce and carry larger oocytes may be linked to larger females starting the nesting season with greater lipid stores (which we document here) or to greater space within the abdomen of larger females. Compared to other species of solitary bees, M. rotundata appears to have (1) smaller oocytes than solitary nest-provisioning bees in general, (2) comparable oocyte sizes relative to congeners, and (3) larger oocytes than related brood parasitic megachilids
Sustainable Supply Chain Management Programs In The 21st Century
One of the most difficult challenges for an undergraduate supply chain management program at smaller universities is to create an environment of sustainability. Supply chain management is not at the tip of tongue for many graduating high school students and few undergraduate curriculums require a course in the content area. This research addresses undergraduate supply chain management programs, how best to develop a viable program (from a curriculum and operational perspective), and how to create a program that is sustainable with limited resources
Joint Diagonalization Applied to the Detection and Discrimination of Unexploded Ordnance
Efforts to discriminate buried unexploded ordnance from harmless surrounding clutter are often hampered by the uncertainty in the number of buried targets that produce a given detected signal. We present a technique that helps determine that number with no need for data inversion. The procedure is based on the joint diagonalization of a set of multistatic response (MSR) matrices measured at different time gates by a time-domain electromagnetic induction sensor. In particular, we consider the Naval Research Laboratoryās Time-Domain Electromagnetic Multisensor Towed Array Detection System (TEMTADS), which consists of a 5Ć5 square grid of concentric transmitter/receiver pairs. The diagonalization process itself generalizes one of the standard procedures for extracting the eigenvalues of a single matrix; in terms of execution time, it is comparable to diagonalizing the matrices one by one. We present the method, discuss and illustrate its mathematical basis and physical meaning, and apply it to several actual measurements carried out with TEMTADS at a test stand and in the field at the former Camp Butner in North Carolina. We find that each target in a measurement is associated with a set of nonzero time-dependent MSR eigenvalues (usually three), which enables estimation of the number of targets interrogated. These eigenvalues have a characteristic shape as a function of time that does not change with the location and orientation of the target relative to the sensor. We justify analytically and empirically that symmetric targets have pairs of eigenvalues with constant ratios between them
Solution-Phase Synthesis of Heteroatom-Substituted Carbon Scaffolds for Hydrogen Storage
This paper reports a bottom-up solution-phase process for the preparation of pristine and heteroatom (boron, phosphorus, or nitrogen)-substituted carbon scaffolds that show good surface areas and enhanced hydrogen adsorption capacities and binding energies. The synthesis method involves heating chlorine-containing small organic molecules with metallic sodium at reflux in high-boiling solvents. For heteroatom incorporation, heteroatomic electrophiles are added to the reaction mixture. Under the reaction conditions, micrometer-sized graphitic sheets assembled by 3ā5 nm-sized domains of graphene nanoflakes are formed, and when they are heteroatom-substituted, the heteroatoms are uniformly distributed. The substituted carbon scaffolds enriched with heteroatoms (boron ~7.3%, phosphorus ~8.1%, and nitrogen ~28.1%) had surface areas as high as 900 m^2 g^(ā1) and enhanced reversible hydrogen physisorption capacities relative to pristine carbon scaffolds or common carbonaceous materials. In addition, the binding energies of the substituted carbon scaffolds, as measured by adsorption isotherms, were 8.6, 8.3, and 5.6 kJ mol^(ā1) for the boron-, phosphorus-, and nitrogen-enriched carbon scaffolds, respectively
Evaluation of a pilot police led suicide early alert surveillance strategy in the United Kingdom.
Introduction: Those bereaved by suicide are at increased risk of psychological harm, which can be reduced with the provision of timely support. This paper outlines an evaluation of a pilot police-led suicide strategy, in comparison to a coroner-led suicide strategy looking at the number, and length of time it takes for deaths to be recorded for each strategy. Additionally, the police-led strategy offers timely contact from support services for bereaved individuals. We examined what impact this offer of support had on the capacity of support services. Methods: A mixed methods evaluation compared how long it took for suspected suicides to be recorded using both strategies. The number of referrals received by support services during the pilot strategy were compared to those from previous years. A feedback focus group, and interviews, were held with key stakeholders. Results: The coroner-strategy was more consistent at identifying suspected suicides, however reports were filed quicker by the police. Bereaved individuals were willing to share contact details with police officers and consent for referral to support services which lead to increased referrals. The focus group and interviews revealed that the pilot police strategy needs better integration into routine police practice. Conclusions: This strategy has the potential to deliver a real benefit to those bereaved by suicide, however there are still aspects which could be improved
Assessing Ozone-Related Health Impacts under a Changing Climate
Climate change may increase the frequency and intensity of ozone episodes in future summers in the United States. However, only recently have models become available that can assess the impact of climate change on O(3) concentrations and health effects at regional and local scales that are relevant to adaptive planning. We developed and applied an integrated modeling framework to assess potential O(3)-related health impacts in future decades under a changing climate. The National Aeronautics and Space AdministrationāGoddard Institute for Space Studies global climate model at 4Ā° Ć 5Ā° resolution was linked to the Penn State/National Center for Atmospheric Research Mesoscale Model 5 and the Community Multiscale Air Quality atmospheric chemistry model at 36 km horizontal grid resolution to simulate hourly regional meteorology and O(3) in five summers of the 2050s decade across the 31-county New York metropolitan region. We assessed changes in O(3)-related impacts on summer mortality resulting from climate change alone and with climate change superimposed on changes in O(3) precursor emissions and population growth. Considering climate change alone, there was a median 4.5% increase in O(3)-related acute mortality across the 31 counties. Incorporating O(3) precursor emission increases along with climate change yielded similar results. When population growth was factored into the projections, absolute impacts increased substantially. Counties with the highest percent increases in projected O(3) mortality spread beyond the urban core into less densely populated suburban counties. This modeling framework provides a potentially useful new tool for assessing the health risks of climate change
Instructors\u27 Conceptions of Reflective Learning: A Phenomenographic Study
Reflective learning has been considered an important learning experience in higher education because of its value for personal and professional self. Despite the potential benefits, there is diverse interpretation of the meaning and process of reflective learning. Theoretical frameworks and models that purport to explain what it entails abound; however, there is a dearth of research that explores conceptions from the perspective of instructors. This study examined university instructorsā conceptions of reflective learning in the context of education courses. Semi-structured interviews were employed to collect data from 32 instructors who consented to participate. The interviews were transcribed, segmented, coded and compared. Our phenomenographic analysis resulted in four qualitatively different conceptions of reflective learning: critical engagement with content, improving professional practice, identity development, and developing critical consciousness. The study has implications for faculty development and research on reflective learning
Navigating Digital Ethics for Rural Research : Guidelines and recommendations for researchers and administrators of social media groups
This document was produced as a deliverable of the research project āNavigating Digital Ethics for Rural Research: Guidelines and recommendations for researchers and administrators of social media groupsā (DigiEthics). Digiethics is a transdisciplinary project seeking to advance digital ethics by co-designing guidelines for engaging Facebook groups. This project was funded by the by the British Academy Early Career Research Network Scotland Hub Seed Fund 2023. This document is available online with background information at: https://www.hutton.ac.uk/research/ projects/digiethics-navigating-digital-ethics-rural-research If you have read/used this document and you have any comments or feedback you would like to share with us, we would love to hear from you. Please contact [email protected] PD
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