Temperature coefficients and radiation induced DLTS spectra of MOCVD grown n(+)p InP solar cells

The effects of temperature and radiation on n(+)p InP solar cells and mesa diodes grown by metallorganic chemical vapor deposition (MOCVD) were studied. It was shown that MOCVD is capable of consistently producing good quality InP solar cells with Eff greater than 19 percent which display excellent radiation resistance due to minority carrier injection and thermal annealing. It was also shown that universal predictions of InP device performance based on measurements of a small group of test samples can be expected to be quite accurate, and that the degradation of an InP device due to any incident particle spectrum should be predictable from a measurement following a single low energy proton irradiation

Assessing Dynamic Efficiency: Theory and Evidence

The issue of dynamic efficiency is central to analyses of capital accumulation and economic growth. Yet the question of what operating characteristics of an economy subject to productivity shocks should be examined to determine whether or not it is efficient has not been resolved. This paper develops criterion based on observables for determining whether or not an economy is dynamically efficient. The criterion involves a comparison of the cash flows generated by capital with the volume of investment. Its application to the United States economy and the economies of other major OECD nations suggests that they are dynamically efficient.

Insights of Precision Medicine Initiative’s All of Us Research Program in Mississippi

While a key component of eliminating health disparities in rural areas is successfully conducting participatory research, many barriers prevent implementation of research projects due to lack of trust in minority communities. Adverse experiences and historical prejudices have left an indelible mark of skepticism and misinformation among these populations and established a breach of communication between researchers and potential participants.The All of Us Research Program led by the National Institute of Health (NIH) at the University of Mississippi Medical Center (UMMC) in Jackson, Mississippi seeks to both improve communication regarding population research studies among rural Mississippi populations and build trust in the community by leveraging grant partnerships with similar aims. UMMC is home to numerous community-based grant programs with a focus on rural medicine and health disparities. UMMC’s name recognition within the state supports the objective of establishing integrity and longevity for its community-based programs. Through the formation of partnerships with research programs of corresponding demographic aims, All of Us can improve its engagement impact, and develop relationships that will serve as the underpinning of program recruitment.A number of UMMC community-based programs have been identified and work has begun to create a footprint in rural areas where disparities have been prevalent. UMMC operates a school-based clinic program in the Mississippi Delta to offer free clinical care to students, staff, and the community at large. All of Us has already partnered with an initial educational event and additional opportunities are planned to optimize our presence in this area. The CEAL grant provides educational awareness related to COVID vaccines and clinical intervention through evidence-based practices. The Department of Preventive Medicine operates a resident-run, community wellness clinic that travels throughout the state to provide baseline well checks to underserved communities. Our institutional aim of reducing health disparities and implementing positive, validated messaging around research provides a shared framework in which we can engage. These programs all seek to improve community relations and assess research perceptions. Further, they all aim to provide health resources for those who are underserved. Community outreach will be more successful when partnerships demonstrate cohesive goals, providing a unified presence that initiates trust. Relationships can continue to build on that trust through consistent visits and activities that enrich the community. All of Us has experienced initial success using the partner program approach and will track the progress of engagement activities as this endeavor continues throughout the grant year

Policymaking for Posterity

Policymaking for posterity involves current decisions with distant consequences. Contrary to conventional prescriptions, we conclude that the greater wealth of future generations may strengthen the case for preserving environmental amenities; lower discount rates should be applied to the far future, and special effort should be made to avoid actions that impose costs on future generations. -- Posterity brings great uncertainties. Even massive losses, such as human extinction, however, do not merit infinite negative utility. Given learning, greater uncertainties about damages could increase or decrease the optimal level of current mitigation activities. -- Policies for posterity should anticipate effects on: alternative investments, both public and private; the actions of other nations; and the behaviors of future generations. Such effects may surprise. -- This analysis blends traditional public finance and behavioral economics with a number of hypothetical choice problems.

Duration-dependent effects of the BDNF Val66Met polymorphism on anodal tDCS induced motor cortex plasticity in older adults: a group and individual perspective

The brain derived neurotrophic factor (BDNF) Val66Met polymorphism and stimulation duration are thought to play an important role in modulating motor cortex plasticity induced by non-invasive brain stimulation (NBS). In the present study we sought to determine whether these factors interact or exert independent effects in older adults. Fifty-four older adults (mean age = 66.85 years) underwent two counterbalanced sessions of 1.5 mA anodal transcranial direct current stimulation (atDCS), applied over left M1 for either 10 min or 20 min. Single pulse transcranial magnetic stimulation (TMS) was used to assess corticospinal excitability (CSE) before and every 5 min for 30 min following atDCS. On a group level, there was an interaction between stimulation duration and BDNF genotype, with Met carriers (n =13) showing greater post-intervention potentiation of CSE compared to Val66Val homozygotes (n = 37) following 20 min (p = 0.002) but not 10 min (p = 0.219) of stimulation. Moreover, Met carriers, but not Val66Val homozygotes, exhibited larger responses to TMS (p = 0.046) after 20 min atDCS, than following 10 min atDCS. On an individual level, two-step cluster analysis revealed a considerable degree of inter-individual variability, with under half of the total sample (42%) showing the expected potentiation of CSE in response to atDCS across both sessions. Intra-individual variability in response to different durations of atDCS was also apparent, with one-third of the total sample (34%) exhibiting LTP-like effects in one session but LTD-like effects in the other session. Both the inter-individual (p = 0.027) and intra-individual (p = 0.04) variability was associated with BDNF genotype.In older adults, the BDNF Val66Met polymorphism along with stimulation duration appears to play a role in modulating tDCS-induced motor cortex plasticity. The results may have implications for the design of NBS protocols for healthy and diseased aged populations

Cowbird Control: Management Issues, Controversies and Perceptions, and the Future

Brood-parasitic brown-headed cowbirds (Molothrus ater) have been implicated as a cause of songbird population declines. Cowbirds can have particularly severe negative impacts on already endangered hosts. Removal of cowbirds by trapping has become a popular management action to benefit hosts. Cowbird trapping often decreases parasitism frequency and can help to increase the reproductive success of hosts. However, its role in the recovery of host populations is equivocal. Based on our experience at Fort Hood Military Reservation, Texas, the site of a long-term, landscape-scale trapping program, we discuss factors that we believe are important for the success of a trapping program (e.g., timing of trapping). Although cowbird removal is generally accepted as a songbird conservation tool, its use is not without controversy. So, we also review some of the economic, ethical, legal, and scientific issues associated with cowbird trapping. Ultimately, our continued ability to remove cowbirds as a tool for songbird conservation may depend on the resolution of these controversies. Although cowbird removal may not be a viable long-term solution to songbird population declines in of itself, it can be an integral part of integrated songbird management strategies

The Role for Coagulation Markers in Mild Snakebite Envenomations

Introduction: The majority of patients seeking medical treatment for snakebites do not suffer from severe envenomation. However, no guidelines exist for ordering coagulation markers in patients with minimal or moderate envenomation, nor in those who do not receive antivenom. In this study, we sought to determine whether it was possible to limit the practice of ordering coagulation studies to those patients suffering severe envenomation, rattlesnake envenomation, or both.Methods: A retrospective chart review was performed on all cases of crotalid snakebite presenting to an adult emergency department (ED) from April 1998 to June 2006. Each chart was abstracted for patient’s age, gender, type of snake (if known), severity of envenomation at initial presentation, coagulation test results, whether antivenom was administered, and whether the patient was admitted.Results: Over an approximately 8-year period, 131 snakebite cases presented that met the inclusion criteria, of which 35 (26.7%) had some type of coagulation marker abnormality. Limiting coagulation testing to patients suffering severe envenomation or rattlesnake envenomation would have resulted in failure to identify 89% or 77%, respectively, of the 35 patients who were found to have at least 1 abnormal coagulation marker.Conclusion: Our study failed to identify a subset of patients that could be defined as low risk or for whom coagulation marker testing could be foregone. This study suggests that coagulation tests should be routinely performed on all patients presenting to the ED with complaints of envenomation by copperheads, moccasins, or rattlesnakes. Further clarification of when coagulation markers are indicated may require a prospective study that standardizes snake identification and the timing of coagulation marker testing. [West J Emerg Med. 2012;13(1):68–74.