Development of N/P AlGaAs free-standing top solar cells for tandem applications

The combination of a free standing AlGaAs top solar cell and an existing bottom solar cell is the highest performance, lowest risk approach to implementing the tandem cell concept. The solar cell consists of an AlGaAs substrate layer, an AlGaAs base layer, an AlGaAs emitter, and an ultra-thin AlGaAs window layer. The window layer is compositionally graded which minimizes reflection at the window layer/emitter interface and creates a built-in electric field to improve quantum response in the blue region of the spectrum. Liquid phase epitaxy (LPE) is the only viable method to produce this free standing top solar cell. Small (0.125 sq cm), transparent p/n AlGaAs top solar cells were demonstrated with optimum bandgap for combination with a silicon bottom solar cell. The efficiency of an AlGaAs/Si stack using the free standing AlGaAs device upon an existing silicon bottom solar cell is 24 pct. (1X, Air Mass Zero (AM0). The n/p AlGaAs top solar cell is being developed in order to facilitate the wiring configuration. The two terminal tandem stack will retain fit, form, and function of existing silicon solar cells. Progress in the development of large area (8 and 16 sq cm), free standing AlGaAs top solar cells is discussed

New insights into the cardiorespiratory physiology of weaned southern elephant seals (Mirounga leonina)

Southern elephant seal (Mirounga leonina) pups must strike a balance between conserving energy during their post-weaning fast and simultaneously developing diving abilities to attain nutritional independence. Little is known about environmental influences on cardiorespiratory patterns, hence energy use, throughout the 6 week fast. Continuous heart rates were recorded for free-ranging, newly weaned southern elephant seals using heart rate time-depth recorders for 5-9 days at Sub-Antarctic Macquarie Island, during October 1994 (n = 1), 1995 (n = 4) and 1996 (n = 1). Daytime observations of respiration and behaviour were made throughout. We present the first instance of synchronous heart rate traces recorded simultaneously for individual weaners. Generalized additive models revealed that a sinusoidal pattern of diurnal heart rate elevation and nocturnal depression was evident in all seals and, on at least one occasion, a conspicuous break in this pattern coincided with an extreme cold weather event. Seals in this study were capable of considerable cardiorespiratory control and regularly demonstrated bradycardia during periods of resting apnoea. Apnoeic duration ranged from 33 to 291 s (mean 134 s). Apnoeic heart rates (mean 67 ± 15 beats min(-1), range 40-114 beats min(-1)) were on average 19.7% lower than those exhibited during periods of eupnoea (mean 83 ± 15 beats min(-1), range 44-124 beats min(-1)). The early development of the cardiorespiratory response is characterized by arrhythmic heart and respiration rates. The strong temporal patterns observed are being driven by the opposing requirements of maximizing time spent fasting in order to develop diving capabilities and of maximizing departure mass. This pilot study has highlighted a potentially large effect of ambient weather conditions on newly weaned southern elephant seal cardiorespiratory activity. Given the increasing westerlies and more erratic and increasing storminess associated with the Southern Annular Mode predicted in the Southern Ocean, the patterns observed here warrant further investigation

Associations between comorbid disease outcomes among patients with depression in a student run free clinic

Background: Research demonstrates a correlation between diagnosed depression and increased markers of chronic medical illness, including poorer glycemic control, increased risk for cardiovascular events, and obesity. Moreover, medically underserved patient populations are especially at high risk for poor health outcomes due to chronic illness, which has profound implications for both individual patients as well as the healthcare system. However, very little research has been done on chronic health outcomes among underserved mental health patients treated in integrated behavioral health/primary medical care settings. MedZou, a student-run, free medical clinic provides integrated health care services to uninsured, low-income adults in Mid-Missouri, and provides a potentially ideal setting for this research. We wanted to compare health outcomes between patients identified with depression and those without depression that were treated at MedZou

Getting To Excellence: What Every Educator Should Know About Consequences of Beliefs, Attitudes, and Paradigms for the Reconstruction of an Academically Unacceptable Middle School

In this chapter a discussion of a salient dimension of the external environment in which today’s educators find themselves practicing – the policy context - is presented. Critical elements of this discussion include a truncated history of the encroachment on local control of the schools and the ensuing standardized-tests-based accountability and standardized testing movement. We also pay some attention to growing efforts to push back against these movements. We conclude this chapter with perspectives of a set of scholarly informants on quality, equity, and adequacy. Our effort in this chapter is to trace the political distance traveled from education defined by the diverse beliefs, values, attitudes and paradigms specific to the New England, Middle, and Southern colonies to the current emphasis on standardized-tests-based accountability, standards, and testing as they impact or fail to impact quality, equity, and adequacy – the context in which the Willie Ray Smith, Sr. Science and Medical Technology Magnet Middle School was previously branded academically unacceptable but now academically acceptable

Leading sustainable improvement in university teaching and learning : Lessons from the sector

Overall, the investigation found that universities that wish to improve the quality of teaching and learning should take an approach that aims to be: collaborative and developmental; embedded; sustainable; and focused on enabling innovation and enhancement. The seven interlinked insights characteristic of sustainable, positive change in teaching and learning in Australian universities are as follows. 1. Efforts to improve the quality of teaching and learning are aligned with the strategic direction of the university The evidence indicates that efforts to improve the quality of teaching and learning within an institution should be aligned with the strategic direction of the university. While this might seem self evident, the findings indicate that there are sometimes tensions between overall institutional priorities and efforts to enhance the quality of teaching and learning. Careful strategic thinking can ensure efforts to enhance teaching and learning provide a means through which universities can enact aspects of their strategic plans. 2. Senior executives support teaching and learning enhancement, and resources for those improvements are allocated as part of the universityʼs planning and budget cycle The study found that embedding and sustaining good teaching and learning practice requires high-level support within an institution. In addition to providing stable representation and championing of teaching and learning, effective support was found to also incorporate institutional investment in the form of funding and resourcing positions and initiatives. It was found that sustainability relies on institutional funding that ensured ongoing impetus for, and successful work in, enhancing teaching and learning. 3. Staff workload allocations allow time for innovation, enhancement and improvement in teaching and learning The project findings indicate that the major factor inhibiting efforts to improve teaching and learning is high staff workloads and the consequent lack of time to engage with, and contribute to, teaching and learning enhancement efforts. This finding mirrors those of several other recent Australian studies of the changing academic profession, although this current project notes the applicability of workload matters to both academic and professional staff. If leaders in Australian universities wish to enhance teaching and learning, fresh thinking, policy and planning is needed around academic and professional staff roles and workload allocation. 4. Effective leadership proactively manages tensions between discipline research endeavours and efforts to improve teaching and learning This research found that a major cultural impediment to enhancing teaching and learning is the privileging of research over teaching and learning within an institution. The findings suggest that effective leadership and management of the tensions that arise between research endeavours and efforts to improve teaching and learning are critical if the latter are to be successful. The findings suggest that the reconciliation of research and teaching and learning can be achieved to some extent through a range of means, including the facilitation of research and scholarship around teaching and learning. Leading sustainable change in university teaching and learning: Lessons from the sector 6 5. Teaching and learning are supported by relevant research and scholarship conducted within the institution and in collaboration with other institutions and relevant bodies The study findings indicate the importance of research and scholarship in the area of teaching and learning. External interface, networking and exchange with stakeholders and bodies outside the institution are critical to ensuring enhancement efforts fit with the broader context in which they are occurring. Some of the benefits of engaging in such research and scholarship were: increased reflection on practice; a heightened awareness of the link between an individualʼs own teaching and their studentsʼ outcomes; increased innovation in teaching; improved morale; enhancing the quality of teaching and learning both within an institution and more broadly; and opportunities to both benchmark and improve teaching performance. The potential for research into teaching and learning to contribute to resolving the tensions between discipline research and teaching and learning was also noted. 6. A distributed teaching and learning support structure exists within the institution and is coordinated from the centre The findings of this research showed that a distributed institutional support structure for teaching and learning enhancement, coordinated from the centre, was perceived to be the most effective approach. Most commonly this involved cooperation between a central teaching and learning centre and one or more of: teaching and learning committees; the associate deans (teaching and learning) or equivalent; educational development and other staff located in the faculties; and a critical mass of people with a commitment to teaching and learning improvement and enhancement who have the capacity to lead. 7. Mechanisms to recognise excellence in teaching and learning and to enable teaching and learning career pathways are in place This study found that professional development, reward and recognition mechanisms and enabling career pathways for those committed to teaching and learning are important components in the successful leadership of teaching and learning enhancement. The project findings indicate the centrality of linking efforts to enhance teaching and learning with promotion opportunities. The research findings indicate that university promotion criteria that incorporate excellence in teaching and learning scholarship and practice allow appropriate recognition, enable the sustainability of excellent practice and help embed enhancement

Development of a lightweight, light-trapped, thin GaAs solar cell for spacecraft applications

This paper describes ultra-lightweight, high performance, thin, light trapping GaAs solar cells for advanced space power systems. The device designs can achieve 24.5 percent efficiency at AMO and 1X conditions, corresponding to a power density of 330 W/m2. A significant breakthrough lies in the potential for a specific power of 2906 W/kg because the entire device is less than 1.5 microns thick. This represents a 440 percent improvement over conventional 4-mil silicon solar cells. In addition to being lightweight, this thin device design can result in increased radiation tolerance. The attachment of the cover glass support to the front surface has been demonstrated by both silicone and electrostatic bonding techniques. Device parameters of 1.002 volts open-circuit voltage, 80 percent fill factor, and a short-circuit current of 24.3 mA/sq cm have been obtained. This demonstrates a conversion efficiency of 14.4 percent resulting in a specific power of 2240 W/kg. Additionally, this new technology offers an alternative approach for enabling multi-bandgap solar cells and high output space solar power devices. The thin device structure can be applied to any 3-5 based solar cell application, yielding both an increase in specific power and radiation tolerance

Caffeine for reducing bird damage to newly seeded rice

The economic impact of blackbirds can be severe to rice producers in the United States. One approach to managing this damage is the application of bird-deterrent chemical to the crop. Previous pilot trials suggested that caffeine offered potential as a safe, economical bird repellent. In this study, cage feeding trials with female red-winged blackbirds and male brown-headed cowbirds confirmed that a treatment rate of 2500 ppm caffeine on rice seed reduced consumption as much as 76%. Trials with mixed species blackbird flocks in a 0.2-ha flight pen resulted in just 4% loss of caffeine-treated rice compared to 43% loss of untreated rice. Field trials of a 10,000 ppm caffeine treatment in Louisiana revealed 490% of caffeine-treated rice seed remained unconsumed on days 2 and 3 of the study whereas blackbirds consumed 480% of the untreated seed. As a rice seed treatment to deter blackbirds, caffeine appears to be effective, economical and environmentally safe, although additional aquatic toxicity testing is desirable. Improvements in formulation will be needed to make the compound practical for general agricultural spray applications and to extend the adherence of caffeine to rice seeds in field conditions

Apolipoprotein-ε4 is Associated with Higher Fecundity in a Natural Fertility Population

In many populations, the apolipoprotein-ε4 (APOE-ε4) allele increases the risk for several chronic diseases of aging, including dementia and cardiovascular disease; despite these harmful effects at later ages, the APOE-ε4 allele remains prevalent. We assess the impact of APOE-ε4 on fertility and its proximate determinants (age at first reproduction, interbirth interval) among the Tsimane, a natural fertility population of forager-horticulturalists. Among 795 women aged 13 to 90 (20% APOE-ε4 carriers), those with at least one APOE-ε4 allele had 0.3 to 0.5 more children than (ε3/ε3) homozygotes, while those with two APOE-ε4 alleles gave birth to 1.4 to 2.1 more children. APOE-ε4 carriers achieve higher fertility by beginning reproduction 0.8 years earlier and having a 0.23-year shorter interbirth interval. Our findings add to a growing body of literature suggesting a need for studies of populations living in ancestrally relevant environments to assess how alleles that are deleterious in sedentary urban environments may have been maintained by selection throughout human evolutionary history