Laboratory studies of atomic oxygen reactions with solids

Atomic beam experiments were performed to investigate the rate of atomic oxygen etching of carbon and polyimide films. The main emphasis of these experiments was on gaining an understanding of the role of atomic oxygen translational energy and substrate temperature in promoting the reactions. The experimental facility and techniques are described and results reviewed

Professional Development Impact on Quality Interactions in Home-Based Early Childhood Settings

Recent literature was examined to explore the relationship between professional development and quality interactions in home-based early childhood settings. Home-based child care was identified as a setting preferred by parents (Melvin et al., 2022). However, the educators in these settings often worked alone, worked long hours, and were less likely to have a degree than educators in other early childhood settings (Durden et al., 2016). The understanding of what constituted quality in these under-recognized settings was more challenging to quantify and less studied than quality in other early education settings (Han et al., 2021). A thorough literature review was conducted, and data was synthesized to extract information about home-based settings, degree attainment, professional development needs, quality indicators, and how educators in these settings defined quality. Other factors that may impact quality interactions were identified. Home-based early childhood educators overwhelmingly were found to view themselves as professionals and defined quality in home-based settings differently than measurement tool definitions (Hooper et al., 2021). Process and practical quality were surmised to be the niche in which home-based educators excel (Lanigan, 2011). It was found that supporting this subset of early childhood educators required regular and ongoing professional development that honored and acknowledged the uniqueness of this setting (Abell et al., 2014; Durden et al., 2016)

Application of an atomic oxygen beam facility to the investigation of shuttle glow chemistry

A facility for the investigation of the interactions of energetic atomic oxygen with solids is described. The facility is comprised of a four chambered, differentially pumped molecular beam apparatus which can be equipped with one of a variety of sources of atomic oxygen. The primary source is a dc arc heated supersonic nozzle source which produces a flux of atomic oxygen in excess of 10 to the 15th power sq cm/sec at the target, at a velocity of 3.5 km/sec. Results of applications of this facility to the study of the reactions of atomic oxygen with carbon and polyimide films are briefly reviewed and compared to data obtained on various flights of the space shuttle. A brief discussion of possible application of this facility to investigation of chemical reactions which might contribute to atmosphere induced vehicle glow is presented

Characterization of thiG Gene in B. cepacia as a Thiazole Synthase

Burkholderia cepacia is a gram-negative bacterium found in water and soil that is known to cause infection in plants and humans. Limited treatments are available for this bacteria due to widespread antibiotic resistance and a lack of knowledge of the mechanisms of virulence used by B. cepacia. This work seeks to identify virulence factors needed for pathogenesis. Transposon mutagenesis in B. cepacia ATCC 25416 was used to generate mutants that were screened for defects in pathogenesis in an onion infection model and mutant 370 was selected for further studies. Recent data from the model demonstrate that the mutant produced smaller wound sizes beginning at 48 hours post-infection, indicating that the gene product may be involved in promoting infection in a host. Genetic characterization of mutant 370 determined that the mutation occurred in the thiG gene on chromosome 1, whose product is predicted to be a thiazole synthase, which is likely used in the metabolic processes of the bacteria and could play a role in infection. The transmembrane hydropathy plot suggests that the gene product is found in the cytoplasm, which corresponds to its expected use in the metabolism. Examination of the growth and biofilm production assays revealed that the thiG mutant displays stunted growth and limited biofilm production, suggesting that thiG is not involved in virulence but instead plays an important role in the basic metabolism of the bacteria. Future research will focus on determining thiG’s involvement in metabolism to determine if thiG could be an important target for antibacterials.https://digitalcommons.snc.edu/collaborative_presentations/1082/thumbnail.jp

Perceived organizational support, organizational cynicism and employee well-being

The present study examined how an employee’s perception of their employing organization can impact his or her thoughts, feelings and behaviors. This study examined cognitive, affective and behavioral organizational cynicism in relation to perceived organizational support. Psychological strain, self-reported physical health and turnover intentions were investigated in relation to reduced POS and increased organizational cynicism. An online questionnaire measuring perceived organizational support (POS), organizational cynicism, psychological strain, turnover intentions and self-reported physical health was administered to full-time American employees, who were not self-employed, via links posted to social media websites and also circulated through a manufacturing company’s human resources headquarters. Two groups of participants responded, yielding a total sample of 161 participants. Group 1 consisted of participants from all industry types recruited using social media. Group 2 consisted of employees from the human resources headquarters of the manufacturing company. Groups differed significantly on almost all variables. This difference was controlled for in all analyses. Correlations and multiple regression analyses were used to test the hypotheses. All of the hypothesized correlational relationships were supported. Results of this study supported the notion that the multi-dimensional attitude of organizational cynicism is strongly and inversely related to POS. Contrary to predictions, affective and cognitive organizational cynicism did not mediate the majority of the hypothesized relationships between variables. This may have been due to the multicollinearity of the predictor variables. Significant mediation analyses results included: full mediation between POS and social dysfunction by cognitive organizational cynicism; partial mediation between anxiety/depression and self-reported physical health by affective organizational cynicism; and, the partial mediation of affective organizational cynicism between POS and turnover intentions. Future research may benefit from measuring the variables at different points in time in order to investigate causality between variables and also to avoid any statistical confounds such as multicollinearity. The identification of the high correlations between variables may encourage employers to actively attempt to address levels of POS within their organization thus resulting in benefits for employees

The Effects of Antiretroviral Access on the Creation and Maintanence of HIV-Seropositive Identity.

The study of identity based on the presence of disease has traditionally focused on landmark events, such as diagnosis or the introduction of treatment options. These events have been shown to significantly alter so-called “illness identities.” The project was undertaken in Atlanta, GA, which has a relatively high rate of HIV infection and a large number of HIV-related services and support mechanisms. This study contextualizes illness identities within a larger socio-political and economic paradigm, recognizing that individuals use multiple identities to inform their interactions and decisions, specifically those regarding the beginning and continuation of antiretroviral (ARV) treatment. In addition, structural barriers which limit one’s access to ARV treatment are considered within a context of social and economic marginalization and inequitable power relationships within a post-industrial Western society

Turbulence effects on a holographic imaging system

A side-band holographic system used to record particle images in a high enthalpy environment is described. Holographic particle velocity and size data recorded through turbulent air conditions are presented along with the observed turbulence effects on the holographic image quality. The turbulence effects, background mottling, and loss of image resolution are shown to be functions of phase changes along planar and spherical wavefronts and are discussed in terms of the phase structure function and intensity variance. Holographic quality was found to be strongly dependent on the air stream pressure within the Aerodynamic and Propulsion Test Unit (APTU) wind tunnel. Suggestions for measuring the strength of air turbulence within the air stream in terms of the refractive index structure constant are made. Methods for reducing the turbulence effects on the holographic system are also presented

Principals\u27 and teachers\u27 perceptions of teacher supervision

The purpose of this study was twofold: to determine the extent to which professional and bureaucratic approaches are used in schools around the country and to describe to what extent the elements of instructional supervision, professional development, and evaluation are used to supervise teachers. Survey research was used to ascertain the use of these methods. Data collected indicated that professionalism, instructional supervision, and professional development techniques were the dominant approaches to supervision as indicated by administrators and teachers. When disaggregated by elementary and secondary schools and the degree held by the principal, groups were similar in overall use of professionalism, instructional supervision, and professional development, but secondary schools and principals with master\u27s degrees used more bureaucratic and evaluation techniques. Examination of individual questions shows that different approaches are favored in professionalism, instructional supervision, and professional development, according to the demographic. A lack of collaboration, inside and outside the school, was reported. Clinical supervision was used, but, on average, it was only used one to two times yearly, and different aspects of the process were implemented more frequently than others. Most respondents reported differentiation in supervision methods, usually based on tenure and need, and a prescribed evaluation tool was used. More research needs to be done to conclude if professionalism is the dominant approach, or if bureaucracy is making headway because of No Child Left Behind. There are differing perceptions and uses of the techniques based on administrator and teacher, level of the school, and degree held by the principal

Numerical simulations of the type III migration:I. Disc model and convergence tests

We investigate the fast (type III) migration regime of high-mass protoplanets orbiting in protoplanetary disks. This type of migration is dominated by corotational torques. We study the details of flow structure in the planet's vicinity, the dependence of migration rate on the adopted disc model, and the numerical convergence of models (independence of certain numerical parameters such as gravitational softening). We use two-dimensional hydrodynamical simulations with adaptive mesh refinement,based on the FLASH code with improved time-stepping scheme. We perform global disk simulations with sufficient resolution close to the planet, which is allowed to freely move throughout the grid. We employ a new type of equation of state in which the gas temperature depends on both the distance to the star and planet, and a simplified correction for self-gravity of the circumplanetary gas. We find that the migration rate in the type III migration regime depends strongly on the gas dynamics inside the Hill sphere (Roche lobe of the planet) which, in turn, is sensitive to the aspect ratio of the circumplanetary disc. Furthermore, corrections due to the gas self-gravity are necessary to reduce numerical artifacts that act against rapid planet migration. Reliable numerical studies of Type III migration thus require consideration of both the thermal andthe self-gravity corrections, as well as a sufficient spatial resolution and the calculation of disk-planet attraction both inside and outside the Hill sphere. With this proviso, we find Type III migration to be a robust mode of migration, astrophysically promising because of a speed much faster than in the previously studied modes of migration.Comment: 17 pages, 15 figures, submitted to MNRAS. Comments welcom

Adaptive mesh refinement for global stability analysis of transitional flows

In this work, we introduce the novel application of the adaptive mesh refinement (AMR) technique in the global stability analysis of incompressible flows. The design of an accurate mesh for transitional flows is crucial. Indeed, an inadequate resolution might introduce numerical noise that triggers premature transition. With AMR, we enable the design of three different and independent meshes for the non-linear base flow, the linear direct and adjoint solutions. Each of those is designed to reduce the truncation and quadrature errors for its respective solution, which are measured via the spectral error indicator. We provide details about the workflow and the refining procedure. The numerical framework is validated for the two-dimensional flow past a circular cylinder, computing a portion of the spectrum for the linearised direct and adjoint Navier-Stokes operators.Comment: To be submitted ICOSAHOM202