COMPARATIVE ASPECTS OF AFRICANA PHILOSOPHY AND THE CONTINENTAL-ANALYTIC DIVIDE

Critical engagement involving philosophers trained in continental and analytic traditions often takes its purpose to be a reconciliation of tensions arising from differences in style, or method. Critical engagement in Africana philosophy, however, is rarely focused on method, style, or orientation because philosophic research in this field, regardless of orientation, has had to accommodate its empirical grounding in disciplines outside of philosophy. I focus primarily on the comparative dimensions of three important strands of this research: (1) a history of ideas, (2) a problem-orientation, and (3) a sub-area specialization, to indicate why a need to reconcile tensions between continental and analytic orientations has very little currency in Africana philosophy. Socio-economic problems faced by African-descended people require multiple perspectives to accommodate the wide variety of diasporic social contexts for a given proposal. I employ a selection of cases to illustrate how Africana philosophy benefits from an interplay of many intersecting factors and that, as an interdisciplinary area of research with a commitment to the incorporation of multiple perspectives, it fosters cross-pollination and hybridization of continental andanalytic traditions

Space shuttle launch vehicle performance trajectory, exchange ratios, and dispersion analysis

A baseline space shuttle performance trajectory for Mission 3A launched from WTR has been generated. Design constraints of maximum dynamic pressure, longitudinal acceleration, and delivered payload were satisfied. Payload exchange ratios are presented with explanation on use. Design envelopes of dynamic pressure, SRB staging point, aerodynamic heating and flight performance reserves are calculated and included

Perceptions of College Readiness and Social Capital of GED completers in entry-level college courses

Abstract Examining the efficacy of literacy improvement, general education development (GED) completion, and GED completers’ perceptions of college readiness and social capital was the purpose of this study. The participant sample (n=321), derived from the target population (N=1050), consisted of former participants of Adult Literacy Education (ALE)/GED programs in the Greater New Orleans area (GNO), who have earned the GED credential, and, are currently enrolled in entry-level courses at two community colleges in Southeast Louisiana; specifically, in Orleans and St. Bernard parishes. The study was framed by the social capital theoretical perspective. The study used quantitative methodology, with a descriptive, cross-sectional research design. Specific quantitative analyses were employed including; descriptive statistics which were used to characterize the sample and to describe the features of the data; preliminary analysis using principal axis factoring (PAF), to determine survey items that cluster together and to identify relevant factors that influence perceptions of college readiness and social capital; Cronbach’s alpha, to test internal consistency and reliability of the survey instrument; regression analysis, to investigate the relationships between GED completers’ perceptions of college readiness and social capital and their literacy level; and finally, a one-way ANOVA, to compare the means of groups within literacy levels. Using a researcher-created survey instrument with a Likert scale rating of 1-4, perceptions of college readiness and social capital of GED completers were assessed. A field test of 10 participants and an expert panel review ensured validity and reliability of the instrument. The results of this study could serve as a framework for strategic planning of ALE/GED programs, ALE/GED curriculum alignment with high school content and entry-level introductory or developmental college courses, and post-secondary (community college) recruitment endeavors

Effect of Larval Nutrition on Maternal mRNA Contribution to the Drosophila Egg.

Embryonic development begins under the control of maternal gene products, mRNAs and proteins that the mother deposits into the egg; the zygotic genome is activated some time later. Maternal control of early development is conserved across metazoans. Gene products contributed by mothers are critical to many early developmental processes, and set up trajectories for the rest of development. Maternal deposition of these factors is an often-overlooked aspect of parental investment. If the mother experiences challenging environmental conditions, such as poor nutrition, previous studies in Drosophila melanogaster have demonstrated a plastic response wherein these mothers may produce larger eggs to buffer the offspring against the same difficult environment. This additional investment can produce offspring that are more fit in the challenging environment. With this study, we ask whether D. melanogaster mothers who experience poor nutrition during their own development change their gene product contribution to the egg. We perform mRNA-Seq on eggs at a stage where all mRNAs are maternally derived, from mothers with different degrees of nutritional limitation. We find that nutritional limitation produces similar transcript changes at all degrees of limitation tested. Genes that have lower transcript abundance in nutritionally limited mothers are those involved in translation, which is likely one of the most energetically costly processes occurring in the early embryo. We find an increase in transcripts for transport and localization of macromolecules, and for the electron transport chain. The eggs produced by nutrition-limited mothers show a plastic response in mRNA deposition, which may better prepare the future embryo for development in a nutrition-limited environment

S5 0716+714 : GeV variability study

The GeV observations by Fermi-LAT give us the opportunity to characterize the high-energy emission (100 MeV - 300 GeV) variability properties of the BL Lac object S5 0716+714. In this study, we performed flux and spectral analysis of more than 3 year long (August 2008 to April 2012) Fermi-LAT data of the source. During this period, the source exhibits two different modes of flux variability with characteristic timescales of ~75 and ~140 days, respectively. We also notice that the flux variations are characterized by a weak spectral hardening. The GeV spectrum of the source shows a clear deviation from a simple power law, and is better explained by a broken power law. Similar to other bright Fermi blazars, the break energy does not vary with the source flux during the different activity states. We discuss several possible scenarios to explain the observed spectral break.Comment: 21 pages, 10 figures, Accepted for publication in Advances in Space Research journa

Expression and purification of an adenylation domain from a eukaryotic nonribosomal peptide synthetase: Using structural genomics tools for a challenging target

Nonribosomal peptide synthetases (NRPSs) are large multimodular and multidomain enzymes that are involved in synthesising an array of molecules that are important in human and animal health. NRPSs are found in both bacteria and fungi but most of the research to date has focused on the bacterial enzymes. This is largely due to the technical challenges in producing active fungal NRPSs, which stem from their large size and multidomain nature. In order to target fungal NRPS domains for biochemical and structural characterisation, we tackled this challenge by using the cloning and expression tools of structural genomics to screen the many variables that can influence the expression and purification of proteins. Using these tools we have screened 32 constructs containing 16 different fungal NRPS domains or domain combinations for expression and solubility. Two of these yielded soluble protein with one, the third adenylation domain of the SidN NRPS (SidNA3) from the grass endophyte Neotyphodium lolii, being tractable for purification using Ni-affinity resin. The initial purified protein exhibited poor solution behaviour but optimisation of the expression construct and the buffer conditions used for purification, resulted in stable recombinant protein suitable for biochemical characterisation, crystallisation and structure determination

Acoustical and Dynamic Mechanical Characterization of Fiber-Matrix Interface Bonds in Ceramic Composites

Ceramic matrix composites presently being developed are potentially well suited for high temperature structural applications. The character of the fiber-matrix bond plays a significant role in determining the fracture toughness of the material and thus its performance. Increased toughness is achieved by phenomena such as interface debonding and fiber slip or pull-out, which improve material toughness by increasing the energy required to propagate a crack [1]. In a bond that is too weak, the toughening mechanisms are not significant. However, a bond that is too strong permits a crack to propagate directly through a fiber-matrix interface without being significantly affected, resulting in brittle fracture. As a result, care is required in the manufacture of these materials to achieve optimum fiber-matrix bonding [2]. The objective of this work is to develop and evaluate techniques to nondestructively characterize the fiber-matrix interface bonds. The techniques being investigated include ultrasonic velocity and attenuation, acousto-ultrasonic response, and internal dynamic mechanical damping

An adaptive-binning method for generating constant-uncertainty/constant-significance light curves with Fermi-LAT data

We present a method enabling the creation of constant-uncertainty/constant-significance light curves with the data of the Fermi-Large Area Telescope (LAT). The adaptive-binning method enables more information to be encapsulated within the light curve than with the fixed-binning method. Although primarily developed for blazar studies, it can be applied to any sources. This method allows the starting and ending times of each interval to be calculated in a simple and quick way during a first step. The reported mean flux and spectral index (assuming the spectrum is a power-law distribution) in the interval are calculated via the standard LAT analysis during a second step. The absence of major caveats associated with this method has been established by means of Monte-Carlo simulations. We present the performance of this method in determining duty cycles as well as power-density spectra relative to the traditional fixed-binning method.Comment: 17 pages, 13 figures, 5 tables. Submitted to A&