A Study of the Irradiance-and-Temperature-Dependence of Mid-Wave-Infrared (MWIR)Absorption in Indium Antimonide (InSb)

This work entails further investigation of the absorption of photons in indium antimonide (InSb). Previously work at the Air Force Institute of Technology (AFIT) attributed laser blooming effects in InSb focal plane arrays (FPA’s) to the Burstein-Moss effect. The contributing effect is from a decrease in the absorption of the InSb material, such that the transmitted optical energy scatters off the integrated circuitry beneath the InSb thin film back into the optical system. To evaluate this, irradiance-dependent laser-absorption experiments were performed on thinned, InSb wafers prior to their FPA fabrication. The samples were illuminated with a focused CO2 laser at 4.6 μm, and translated along the optical axis to vary the irradiance. A control process to remotely manage the experiment’s apparatuses during data collection has been developed utilizing LabView 8.5. The transmission of the InSb sample was measured at different laser powers and temperatures. As the temperature decreases for a determined laser irradiance, it has been observed that the absorption decreases nonlinearly. A model of the absorption-saturation phenomena is also developed so that agreement between the measured and modeled results can be studied for the carrier lifetime and density of carriers

Maintenance of heterocyst patterning in a filamentous cyanobacterium

In the absence of sufficient combined nitrogen, some filamentous cyanobacteria differentiate nitrogenfixing heterocysts at approximately every 10th cell position. As cells between heterocysts grow and divide, this initial pattern is maintained by the differentiation of a single cell approximately midway between existing heterocysts. This paper introduces a mathematical model for the maintenance of the periodic pattern of heterocysts differentiated by Anabaena sp. strain PCC 7120 based on the current experimental knowledge of the system. The model equations describe a non-diffusing activator (HetR) and two inhibitors (PatS and HetN) that undergo diffusion in a growing one-dimensional domain. The inhibitors in this model have distinct diffusion rates and temporal expression patterns. These unique aspects of the model reflect recent experimental findings regarding the molecular interactions that regulate patterning in Anabaena. Output from the model is in good agreement with both the temporal and spatial characteristics of the pattern maintenance process observed experimentally

The Party’s Over: Sustaining Support Programs When the Funding is Done

In the lifecycle of an engineering education grant, the phase where best practices are sustained and disseminated is perhaps the most crucial stage for maximizing impact. Yet this transition phase often receives the least attention as project team enthusiasm can wane, while funding tapers off, and faculty priorities are pulled in other directions. There are numerous obstacles associated with sustaining program changes, even those perceived as very valuable. Typical challenges are: What happens when the funding runs out? What grant-developed programs should be sustained by the university? Does the institution need to internally allocate resources in an annual budget large enough to replace the grant? Ultimately, sustaining successful programmatic improvements is about “change management” in an institution. In this paper, we will review the literature relating to institutional change in engineering education. We will build on current curriculum change models, in the context of a major engineering education grant at Boise State University that included a variety of curricular enhancements, academic support, and outreach efforts. Over the past two years, the project team focused considerable effort on institutionalizing the most successful programs, and met with mixed results. While many programs will continue and benefit students long-term, other programs, even ones with stellar success and solid assessment, have not been entirely adopted for a number of reasons that we will examine. We will review the role assessment played in the process of program transfer (from the grant to the university) and lessons learned about building alliances with other campus partners to achieve university-level buy-in, well before the last stage of the grant. Finally, we will discuss two factors that are not identified in institutional change literature, but that contributed significantly to the successful transition of our programs—the importance of taking a research based approach, and flexibility in time and resource allocation

Validating Requirements for Fault Tolerant Systems Using Model Checking

Model checking is shown to be an effective tool in validating the behavior of a fault tolerant embedded spacecraft controller. The case study presented here shows that by judiciously abstracting away extraneous complexity, the state space of the model could be exhaustively searched allowing critical functional requirements to be validated down to the design level. Abstracting away detail not germane to the problem of interest leaves by definition a partial specification behind. The success of this procedure shows that it is feasible to effectively validate a partial specification with this technique. Three anomalies were found in the system one of which is an error in the detailed requirements, and the other two are missing/ambiguous requirements. Because the method allows validation of partial specifications, it also is an effective methodology towards maintaining fidelity between a co-evolving specification and an implementation

Nursing Home Staff Palliative Care Knowledge and Practices: Results of a Large Survey of Frontline Workers

CONTEXT: Deficits in quality end-of-life care for nursing home (NH) residents are well known. Palliative care is promoted as an approach to improve quality. The Palliative Care Survey (PCS) is designed to measure NH staff palliative care knowledge and practice. OBJECTIVES: To comparing palliative care knowledge and practices across NH staff roles using the PCS, and to examine relationships between facility characteristics and PCS scores. METHODS: The PCS was administered to frontline NH staff-certified nursing assistants (CNAs), licensed practical nurses (LPNs), registered nurses (RNs), and social workers (SWs)-in 51 facilities in 2012. Descriptive statistics were calculated by job role. Linear mixed effects models were used to identify facility and individual factors associated with palliative care practice and knowledge. RESULTS: The analytic sample included 1200 surveys. CNAs had significantly lower practice and knowledge scores compared to LPNs, RNs, and SWs (P < 0.05). LPNs had significantly lower psychological, end-of-life, and total knowledge scores than RNs (P < 0.05 for all). Although knowledge about physical symptoms was uniformly high, end-of-life knowledge was notably low for all staff. A one-point higher facility star rating was significantly associated with a 0.06 increase in family communication score (P = 0.003; 95% CI: 0.02-0.09; SE = 0.02). Higher penetration of hospice in the NH was associated with higher end-of-life knowledge (P = 0.003; parameter estimate = 0.006; 95% CI: 0.002-0.010; SE = 0.002). Sixty-two percent of respondents stated that, with additional training, they would be interested in being leaders in palliative care. CONCLUSION: Given observed differences in palliative care practice and knowledge scores by staff training, it appears the PCS is a useful tool to assess NH staff. Low end-of-life knowledge scores represent an important target for quality improvement

Design Status of the Capillary Brine Residual in Containment Water Recovery System

One of the goals of the AES Life Support System (LSS) Project is to achieve 98% water loop closure for long duration human exploration missions beyond low Earth orbit. To meet this objective, the AES LSS Project is developing technologies to recover water from wastewater brine; highly concentrated waste products generated from a primary water recovery system. The state of the art system used aboard the International Space Station (ISS) has the potential to recover up to 85% water from unine wastewater, leaving a significant amounts of water in the waste brine, the recovery of which is critical technology gap that must be filled in order to enable long duration human exploration. Recovering water from the urine wastewater brine is complicated by the concentration of solids as water is removed from the brine, and the concentration of the corrosive, toxic chemicals used to stabilize the urine which fouls and degrades water processing hardware, and poses a hazard to operators and crew. Brine Residual in Containment (BRIC) is focused on solids management through a process of "in-place" drying - the drying of brines within the container used for final disposal. Application of in-place drying has the potential to improve the safety and reliability of the system by reducing the exposure to curew and hardware to the problematic brine residual. Through a collaboration between the NASA Johnson Space Center and Portland Status University, a novel water recovery system was developed that utilizes containment geometry to support passive capillary flow and static phase separation allowing free surface evaporation to take place in a microgravity environment. A notional design for an ISS demonstration system was developed. This paper describes the testing performed to characterize the performance of the system as well as the status of the system level design

Hospice in the nursing home: perspectives of front line nursing home staff

OBJECTIVE: Use of hospice has been associated with improved outcomes for nursing home residents and attitudes of nursing home staff toward hospice influences hospice referral. The objective of this study is to describe attitudes of certified nursing assistants (CNAs), nurses, and social workers toward hospice care in nursing homes. DESIGN, SETTING, AND PARTICIPANTS: We conducted a survey of 1859 staff from 52 Indiana nursing homes. MEASUREMENTS: Study data include responses to 6 scaled questions and 3 open-ended qualitative prompts. In addition, respondents who cared for a resident on hospice in the nursing home were asked how often hospice: (1) makes their job easier; (2) is responsive when a patient has symptoms or is actively dying; (3) makes care coordination smooth; (4) is needed; (5) taught them something; and (6) is appreciated by patients/families. Responses were dichotomized as always/often or sometimes/never. RESULTS: A total of 1229 surveys met criteria for inclusion. Of the respondents, 48% were CNAs, 49% were nurses, and 3% were social workers; 83% reported caring for a nursing home patient on hospice. The statement with the highest proportion of always/often rating was 'patient/family appreciate added care' (84%); the lowest was 'hospice makes my job easier' (54%). More social workers responded favorably regarding hospice responsiveness and coordination of care compared with CNAs (P = .03 and P = .05, respectively). CONCLUSIONS: A majority of staff responded favorably regarding hospice care in nursing homes. About one-third of nursing home staff rated coordination of care lower than other aspects, and many qualitative comments highlighted examples of when hospice was not responsive to patient needs, representing important opportunities for improvement

The NewYacc User's Manual

This manual introduces NewYacc, a parser generator system built upon the original yacc system within Unix. NewYacc's principal extension is to provide users with a way to associate rewrite rules with individual productions in the language grammar. These rules are used to describe how the parse tree (which is saved in NewYacc but not in original yacc) should be traversed, plus users can easily control what action is performed at each node in the tree during their traversals. This provides users with great leverage in the construction of a variety of source to source translation tools. This manual assumes a general familiarity with original yacc. (Also cross-referenced as UMIACS-TR-90-141

Continental-scale assessment of genetic diversity and population structure in quaking aspen (Populus tremuloides)

Aim: Quaking aspen (Populus tremuloides) has the largest natural distribution of any tree native to North America. The primary objectives of this study were to characterize range-wide genetic diversity and genetic structuring in quaking aspen, and to assess the influence of glacial history and rear-edge dynamics. Location: North America. Methods: Using a sample set representing the full longitudinal and latitudinal extent of the species’ distribution, we examined geographical patterns of genetic diversity and structuring using 8 nuclear microsatellite loci in 794 individuals from 30 sampling sites. Results: Two major genetic clusters were identified across the range: a southwestern cluster and a northern cluster. The south-western cluster, which included two subclusters, was bounded approximately by the Continental Divide to the east and the southern extent of the ice sheet at the Last Glacial Maximum to the north. Subclusters were not detected in the northern cluster, despite its continent-wide distribution. Genetic distance was significantly correlated with geographical distance in the south-western but not the northern cluster, and allelic richness was significantly lower in south-western sampling sites compared with northern sampling sites. Population structuring was low overall, but elevated in the south-western cluster. Main conclusions: Aspen populations in the south-western portion of the range are consistent with expectations for a historically stable edge, with low within-population diversity, significant geographical population structuring, and little evidence of northward expansion. Structuring within the southwestern cluster may result from distinct gene pools separated during the Pleistocene and reunited following glacial retreat, similar to patterns found in other forest tree species in the western USA. In aspen, populations in the southwestern portion of the species range are thought to be at particularly high risk of mortality with climate change. Our findings suggest that these same populations may be disproportionately valuable in terms of both evolutionary potential and conservation value