Study of advanced InSb arrays for SIRTF (Space Infrared Telescope Facility)

The Santa Barbara Research Center has completed a study leading to the development of advanced Indium Antimonide detector arrays for the Space Infrared Telescope Facility (SIRTF) Focal Plane Array Detector (FPAD) Subsystem of the Infrared Array Camera (IRAC) Band 1. The overall goal of the study was to perform design tradeoff studies, analysis and research to develop a Direct Readout Integrated Circuit to be hybridized to an advanced, high performance InSb detector array that would satisfy the technical requirements for Band 1 as specified in the IRAC Instrument Requirements Document (IRD), IRAC-202. The overall goal of the study was divided into both a near-term goal and a far-term goal. The near-term goal identifies current technology available that approaches, and in some cases meets the program technological goals as specified in IRAC-202. The far-term goal identifies technology development required to completely achieve SIRTF program goals. Analyses of potential detector materials indicates that InSb presently meets all Band 1 requirements and is considered to be the baseline approach due to technical maturity. The major issue with regard to photovoltaic detectors such as InSb and HgCdTe is to achieve a reduction in detector capacitance

Magnetohydrodynamic shock production and current sheet diffusion

NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. Current sheets in inverse pinch MHD shock tubes exhibit the strange property of forming shocks in the very rear of the sheet when accelerating heavy gases. When accelerating light gases, shocks are formed further to the front in the sheet, but in no case do the shocks separate from the driving current sheet. This "piston dragging shock" effect is explained on the basis of a single-fluid model with variable conductivity. Shocks are shown to always form within current sheets which move at supersonic speeds with respect to the driven gas. The relevant parameters for determining the shock position are the Mach number and the magnetic Reynolds number. Large magnetic Reynolds numbers and small Mach numbers enhance forward shock formation. These conditions are obtained in light gases with high speeds of sound. Similarity methods are developed to estimate gas conductivities, electron temperatures, and degrees of ionization for the experiments which are conducted. In hydrogen typical electron temperatures of 4 ev are produced by the ohmic heating, but twice this value is shown necessary to achieve separation at the current sheet speeds of 2-3 [...] used. Higher current sheet speeds produce shocks in the rear of the current sheet where separation can never occur. The correct method of procedure and the relevant design parameters to achieve separation are given. The success of single-fluid methods in explaining plasma phenomena is especially notable, and these methods can be extended to other similar problems. Based on these methods, multiple-fluid and microscopic effects are easily detectable and can be accounted for

A Methodology to Support the Maintenance of Object -Oriented Systems Using Impact Analysis.

Object-Oriented (OO) systems are difficult to understand due to the complex nature of the relationships that object-orientation supports. Inheritance, polymorphism, encapsulation, information hiding, aggregation, and association combine to make maintenance of OO systems difficult. Due to the presence of these characteristics in OO systems, maintenance activities on OO systems often have unexpected or unseen effects on the system. These effects can ripple through system components, complicating maintenance and testing of the system. The ability to trace the effects of maintenance provides the maintainer with knowledge that assists in debugging and testing modified and affected components. In this research, we show that the architecture of an OO system provides an effective framework for determining the impact of system changes. We developed the Comparative Software Maintenance (CSM) methodology to support the maintenance of OO systems. Through this methodology, we model relationships and structures, analyze the models to determine components that change as a result of maintenance, and perform impact analysis to determine components that are candidates for re-testing as a result of maintenance activity. The methodology includes a new data model, called Extended Low-Level Software Architecture (ELLSA), that facilitates impact analysis. CSM locates potential side effects, ripple effects, and other effects of maintenance on class structures, methods, and objects. The comprehensive architecture model enables CSM to perform either predictive, pre-modification impact analysis or post-modification impact analysis. The improved impact analysis process found in the methodology determines impact of changes to the component level. We apply the results of impact analysis to determine component level testing requirements. CSM enhances program understanding through the use of ELLSA. It also provides assistance for capturing complex dependencies found in object-oriented code. The methodology is implemented in JFlex. The automation provided by JFlex makes the application of CSM feasible

What STEM Teachers Need to Know and Do for English Language Learners (ELLs): Using Literacy to Learn

A growing concern for STEM teachers is the responsibility of having students who do not speak English proficiently in their content area classrooms. This paper gives a background of how STEM literacy and English language learner (ELL) literacy can be used productively together as well as strategies for STEM teachers to help all students learn. Strategies for ELL literacy are good strategies for all students. We discuss specific strategies that STEM teachers can use that benefit all students in developing academic language and conceptual understanding in STEM content using a hands-on STEM experiment, “Why do I need to wear a bicycle helmet?” that incorporates Newton’s first, second, and third laws of motion

A proof of the convexity of the range of a nonatomic vector measure using linear inequalities

AbstractThis note shows how a standard result about linear inequality systems can be used to give a simple proof of the fact that the range of a nonatomic vector measure is convex, a result that is due to Liapounoff

What STEM Teachers Need to Know and Do to Engage Families of Emergent Multilingual Students (English Language Learners)

STEM teacher educators are aware that we teach far more than content-specific methodology. Educators need to guide STEM teachers in the knowledge and skills to support emergent multilingual students (English language learners, or ELLs) by simultaneously developing their STEM content learning and scaffolding their language acquisition (Hoffman & Zollman, 2016; Suh, Hoffman, & Zollman, 2020). Research identifies the family unit having a profound effect upon student learning and educational choices. Educators, educational researchers, and policymakers alike recognize the importance of family involvement in education (Grant & Ray, 2019). Although previous family engagement initiatives have focused on teaching families from a school-based perspective (Bush & Cook, 2016), we advocate for a STEM family engagement model which honors and grows out of families’ existing funds of knowledge. This article lays out an argument for STEM teacher educators explicitly addressing multilingual family engagement as a key part of STEM education. We explain purposes, pitfalls, and practical steps STEM teacher educators can utilize that have a positive impact on diverse students’ STEM learning. We also encourage STEM educators to address “STEM mindset” in addition to STEM literacy skills and interdisciplinary STEM content knowledge

Pharmacologic Management of Aggression in Adults with Intellectual Disability

Introduction: Aggression is a common behavioral problem seen in patients with intellectual disabilities (ID). The safety and efficacy of second generation antipsychotics (SGAs), mood stabilizers and antidepressants in the management of aggression in these individuals have minimally been studied. This review aims to 1) summarize the studies conducted using second generation antipsychotics, mood stabilizers and antidepressants in treating aggressive behaviors in patient with ID and 2) determine based on the existing literature, which medications have been examined in the most rigorous study design that might suggest the most efficacy for use in clinical practice.Methods: Literature searches using PUBMED Central, CINAHL Plus, PsychINFO, and Embase databases were conducted using the following terms: intellectual disability/disabilities, mental retardation, developmental disability/disabilities, aggression, agitation, behavior disorder, adult, treatment, management. Studies predominantly including children with ID, and autism/pervasive developmental disabilities spectrum disorders were excluded. Analyses were done by class of medication: SGAs, mood stabilizers and antidepressants. The primary outcome measure was reduction in aggressive or self injurious behaviors as measured by each individual study.Results: The most rigorous study designs found using these agents were randomized controlled trials (RCT). A total of 10 RCTs were found, the majority being with risperidone (3) and lithium (2). Treatment with risperidone showed reduction in aggression when compared to placebo in most RCTs with the exception of one study in which risperidone was not better than placebo. Both lithium studies showed reduction in aggression when compared to placebo. The most abundant literature exists in retrospective chart reviews. The most commonly studied agent was risperidone which showed reduction in aggression in majority of the studies.Conclusions: Limited data exists for treatment of aggression in adults with ID. There are very few studies examining pharmacologic agents using RCTs. Given that risperidone and lithium were the most commonly studied agents in the most rigorous experimental design, it is suggested that these two agents prove efficacious for treatment of aggression in patients with ID. Limitations to most of these studies included concomitant psychotropic administration with variations in types and dosing, severity of ID, and the idea that a wide variety of aggression scales were used to assess outcome. Further research with more scientific rigor is required in this field

Agency Directors And Network Centrality: An Examination Of Resource Dependencies

A basic tenet of resource dependence theory is organizations must obtain resources from their environments in order to survive (Pfeffer and Salancik, 1978). Ac- cording to the theory, there are several strategic factors that affect how organizations manage inter- organizational resource exchanges. These strategic factors include (1) interlocking of board of director members, (2) joint programs or joint ventures, (3) organization size, and (4) top administrator contacts with other organizations (Pfeffer and Salancik 1978: 143-69). Organizations engage in these activities to reduce uncertainty and to develop favorable linkages in interorganizational network

Factors associated with retention in Option B+ in Malawi: a case control study.

IntroductionThere are limited data on factors associated with retention in Option B+. We sought to explore the characteristics of women retained in Option B+ in Malawi, with a focus on the role of HIV disclosure, awareness of partner HIV status, and knowledge around the importance of Option B+ for maternal-child health. Methods We performed a case-control study of HIV-infected women in Malawi initiated on antiretroviral therapy (ART) under Option B+. Cases were enrolled if they met criteria for default from Option B+ (out of ART for >60 days), and controls were enrolled in approximately 3:1 ratio if they were retained in care for at least 12 months. We surveyed socio-demographic characteristics, HIV disclosure and awareness of partner HIV status, self-report about receiving pre-ART education, and knowledge of Option B+. Univariate logistic regression was performed to determine factors associated with retention. Multivariate logistic regression model was used to evaluate the relationship between HIV disclosure, Option B+ knowledge, and retention after adjusting for age, schooling, and travel time to clinic.ResultsWe enrolled 50 cases and 153 controls. Median age was 30 years (interquartile range (IQR) 25-34), and the majority (82%) initiated ART during pregnancy at a median gestational age of 24 weeks (IQR 16-28). Ninety-one per cent of the cases (39/43) who started ART during pregnancy defaulted by three months postpartum. HIV disclosure to the primary sex partner was more common among women retained in care (100% versus 78%, p < 0.001). Odds of retention were significantly higher among women with: age >25 years (odds ratio (OR) 2.44), completion of primary school (OR 3.06), awareness of partner HIV status (OR 5.20), pre-ART education (OR 6.17), higher number of correct answers to Option B+ knowledge questions (OR 1.82), and support while taking ART (OR 3.65). Pre-ART education and knowledge were significantly correlated (r = 0.43, p < 0.001). In multivariate analysis, awareness of partner HIV status (OR 4.07, 95% confidence interval (CI) 1.51-10.94, p = 0.02) and Option B+ knowledge (OR 1.60, 95% CI 1.15-2.23, p = 0.004) remained associated with retention.ConclusionsInterventions that address partner disclosure and strengthen pre-ART education around the benefits of ART for maternal and child health should be evaluated to improve retention in Malawi's Option B+ programme