Miracle-dz/UniFAR-FTUs huggingface dataset:
Factors for academic success among African-American men: A phenomenological study

Academic success among African men has increased but many African-American men continue to fall behind the academic achievements of their Caucasian male counterparts. African-American men who achieve academic success have been marginalized in research that primarily focusses on reporting deficit or negative factors that hinder and not promote academic growth. The purpose of this phenomenological study was to identify environmental, social, and socioeconomic factors that were perceived to contribute to the academic success of African-American men in secondary and post-secondary institutions. The researcher used the Ecological Model of Human Development (EMHD) to identify factors and which systems had the greatest impact on academic achievement. The researcher interviewed ten African-American men who graduated from a secondary and post-secondary institution. All participants were recorded during a semi-structured interview. Each interview was transcribed using the online transcription company Rev. The researcher coded data based on environmental, social, and socioeconomic factors that contributed to their academic success. Data were further coded based on the systems in the EMHD (i.e. microsystem, mesosystem, exosystem, macrosystem, and chronosystem). The researcher identified seven themes that attributed to academic success: • Family • Community members and educator support • Intrinsic motivation • High school and college teacher support • College attendance expectations • Peer influence and motivation • Financial assistance Regardless of research that reports a deficit point of view and the lack of academic achievement among African-American men, positive support from parents, family members, high school and college educators, friends, and members of their community, African-American men can achieve academic success. Even though some AfricanAmerican men may experience many different positive or negative factors in their academic environment, continuous high levels of academic support in high school and college predicted academic success. The microsystem and mesosystem in the EMHD were found to have a greater impact on the academic success among African-American men over all other factors identified within the remaining EMHD systems. APPROVAL FOR SCHOLARLY DISSEMINATION The author grants to the Prescott Memorial Library o f Louisiana Tech University the right to reproduce, by appropriate methods, upon request, any or all portions o f this Dissertation. It is understood that “proper request” consists o f the agreement, on the part o f the requesting party, that said reproduction is for his personal use and that subsequent reproduction will not occur without written approval o f the author o f this Dissertation. Further, any portions o f the Dissertation used in books, papers, and other works must be appropriately referenced to this Dissertation. Finally, the author o f this Dissertation reserves the right to publish freely, in the literature, at any time, any or all portions o f this Dissertation.
On a class of metrics related to graph layout problems

We examine the metrics that arise when a finite set of points is embedded in the real line, in such a way that the distance between each pair of points is at least 1. These metrics are closely related to some other known metrics in the literature, and also to a class of combinatorial optimization problems known as graph layout problems. We prove several results about the structure of these metrics. In particular, it is shown that their convex hull is not closed in general. We then show that certain linear inequalities define facets of the closure of the convex hull. Finally, we characterise the unbounded edges of the convex hull and of its closure.
Adjustment of the Global Climate to an Abrupt Slowdown of the Atlantic Meridional Overturning Circulation

We explore the adjustment of the global climate to an abrupt slowdown of the Atlantic Meridional Circulation (AMOC), with a particular focus on the energetics. The slowdown is induced by a sudden freshwater perturbation in the North Atlantic. Reduction in the AMOC decreases northward ocean heat transport (OHT) and leads to cooling in the northern high latitudes. This cooling results in a local reduction to the top of atmosphere (TOA) radiative heat loss and an increase in northward atmospheric heat transport (AHT). The energy for the increased northward AHT comes from a combination of increased downward radiative flux at the TOA in the southern tropics and anomalous heating from the ocean in the northern tropics, both of which are consequences of the southward shift in the Intertropical Convergence Zone. Hence, viewed in the energetics framework, the atmospheric response to an AMOC slowdown extends throughout the Northern Hemisphere and into the tropics, and suggests an intimate coupling between the two regions. The mechanisms for the high-latitude-tropical coupling are examined. When comparing freshwater perturbation experiments in modern and Last Glacial Maximum (LGM) background states, we found that the changes to the northward OHT, and the mechanisms of global adjustment to the AMOC slowdown, were qualitatively similar in both instances. The one major difference is that freshening in the LGM climate induces a significantly stronger sea ice feedback than in a modern climate, allowing greater local cooling of the North Atlantic, and causing a commensurately larger global climate adjustment.
The Query Change Model

Modern information retrieval (IR) systems exhibit user dynamics through interactivity. These dynamic aspects of IR, including changes found in data, users, and systems, are increasingly being utilized in search engines. Session search is one such IR task—document retrieval within a session. During a session, a user constantly modifies queries to find documents that fulfill an information need. Existing IR techniques for assisting the user in this task are limited in their ability to optimize over changes, learn with a minimal computational footprint, and be responsive. This article proposes a novel query change retrieval model (QCM), which uses syntactic editing changes between consecutive queries, as well as the relationship between query changes and previously retrieved documents, to enhance session search. We propose modeling session search as a Markov decision process (MDP). We consider two agents in this MDP: the user agent and the search engine agent. The user agent’s actions are query changes that we observe, and the search engine agent’s actions are term weight adjustments as proposed in this work. We also investigate multiple query aggregation schemes and their effectiveness on session search. Experiments show that our approach is highly effective and outperforms top session search systems in TREC 2011 and TREC 2012.
The critical Reynolds number of a laminar mixing layer

It has hitherto been widely considered that a mixing layer is unstable at all Reynolds numbers. However this is untenable from energy considerations, which demand that there must exist a non-zero Reynolds number below which disturbances cannot extract energy from the mean flow. It is shown here that a linear stability analysis of similarity solutions of the plane mixing layer, including the effects of flow non-parallelism, using the minimal composite theory and the properties of adjoints following Govindarajan & Narasimha (2005), resolves the issue by yielding non-zero critical Reynolds numbers for coflowing streams of any velocity ratio. The critical Reynolds number so found, based on the vorticity thickness and the velocity differential as scales, varies in the narrow range of 59 to 55 as the velocity ratio goes from zero to unity.
Coarse-grained multiresolution structures for mobile exploration of gigantic surface models

We discuss our experience in creating scalable systems for distributing and rendering gigantic 3D surfaces on web environments and common handheld devices. Our methods are based on compressed streamable coarse-grained multiresolution structures. By combining CPU and GPU compression technology with our multiresolution data representation, we are able to incrementally transfer, locally store and render with unprecedented performance extremely detailed 3D mesh models on WebGL-enabled browsers, as well as on hardware-constrained mobile devices.
Essential Role of RAB27A in Determining Constitutive Human Skin Color

Human skin color is predominantly determined by melanin produced in melanosomes within melanocytes and subsequently distributed to keratinocytes. There are many studies that have proposed mechanisms underlying ethnic skin color variations, whereas the processes involved from melanin synthesis in melanocytes to the transfer of melanosomes to keratinocytes are common among humans. Apart from the activities in the melanogenic rate-limiting enzyme, tyrosinase, in melanocytes and the amounts and distribution patterns of melanosomes in keratinocytes, the abilities of the actin-associated factors in charge of melanosome transport within melanocytes also regulate pigmentation. Mutations in genes encoding melanosome transport-related molecules, such as MYO5A, RAB27A and SLAC-2A, have been reported to cause a human pigmentary disease known as Griscelli syndrome, which is associated with diluted skin and hair color. Thus we hypothesized that process might play a role in modulating skin color variations. To address that hypothesis, the correlations of expression of RAB27A and its specific effector, SLAC2-A, to melanogenic ability were evaluated in comparison with tyrosinase, using human melanocytes derived from 19 individuals of varying skin types. Following the finding of the highest correlation in RAB27A expression to the melanogenic ability, darkly-pigmented melanocytes with significantly higher RAB27A expression were found to transfer significantly more melanosomes to keratinocytes than lightly-pigmented melanocytes in co-culture and in human skin substitutes (HSSs) in vivo, resulting in darker skin color in concert with the difference observed in African-descent and Caucasian skins. Additionally, RAB27A knockdown by a lentivirus-derived shRNA in melanocytes concomitantly demonstrated a significantly reduced number of transferred melanosomes to keratinocytes in co-culture and a significantly diminished epidermal melanin content skin color intensity (ΔL* = 4.4) in the HSSs. These data reveal the intrinsically essential role of RAB27A in human ethnic skin color determination and provide new insights for the fundamental understanding of regulatory mechanisms underlying skin pigmentation.
Contextual Factors Influencing Student Absenteeism at a Higher Education Institution in South Africa

ABSTRACT Student absenteeism at higher education institutions (HEIs) is a cause for concern as it has implications for students’ academic performance and therefore graduation rates. Graduation rates to some extent influence funding to which universities are entitled. This study aimed to establish the contextual factors that influenced student absenteeism at the Durban University of Technology (DUT), South Africa. A cross-sectional, quantitative study was conducted amongst 140 students in a single discipline in the management cluster. First-year students were found to have a greater tendency to be late for the first period (08:00) than second-year or third-year students. Furthermore, the students chose to absent themselves from class to study for tests; complete assignments; or engage in group work. The majority of the students absented themselves from classes on the day before a test as well as on the day of the test. The recommendations that emanated include the need to dedicate time for testing, during which no lectures are scheduled and to plan the timetable so that first-year lectures start in the second period (09:00).
The Evolution of Early-Type Galaxies in Distant Clusters

We present results from an optical-infrared photometric study of early-type (E+S0) galaxies in 19 galaxy clusters out to z = 0.9. The galaxy sample is selected on the basis of morphologies determined from Hubble Space Telescope (HST) WFPC2 images and is photometrically defined in the K band in order to minimize redshift-dependent selection biases. Using new ground-based photometry in five optical and infrared bands for each cluster, we examine the evolution of the color-magnitude relation for early-type cluster galaxies, considering its slope, intercept, and color scatter around the mean relation. New multiwavelength photometry of galaxies in the Coma Cluster is used to provide a baseline sample at z ≈ 0 with which to compare the distant clusters. The optical-IR colors of the early-type cluster galaxies become bluer with increasing redshift in a manner consistent with the passive evolution of an old stellar population formed at an early cosmic epoch. The degree of color evolution is similar for clusters at similar redshift and does not depend strongly on the optical richness or X-ray luminosity of the cluster, which suggests that the history of early-type galaxies is relatively insensitive to environment, at least above a certain density threshold. The slope of the color-magnitude relationship shows no significant change out to z = 0.9, which provides evidence that it arises from a correlation between galaxy mass and metallicity, not age. Finally, the intrinsic scatter in the optical-IR colors of the galaxies is small and nearly constant with redshift, which indicates that the majority of giant, early-type galaxies in clusters share a common star formation history, with little perturbation due to uncorrelated episodes of later star formation. Taken together, our results are consistent with models in which most early-type galaxies in rich clusters are old, formed the majority of their stars at high redshift in a well-synchronized fashion, and evolved quiescently thereafter. We consider several possible effects that may be introduced by the choice of morphologically recognizable elliptical and S0 galaxies in dense environments as a subject for study. In particular, the inclusion of S0 galaxies, which might be undergoing morphological transformation in clusters as part of the Butcher-Oemler effect, may influence the results of our investigation.
SOME TOOLS FOR LINEAR DIMENSION REDUCTION

Dimension reduction refers to a family of methods commonly used in multivariate statistical analysis. The common objective for all dimension reduction methods is essentially the same: the reducing of the number of variables in the data while still preserving their information content, however it is measured. In linear dimension reduction this is done by replacing the original variables with a lesser number of linear combinations of them. Dimension reduction can further be divided into two subcategories: supervised dimension reduction where some (usually one) of the variables clearly have the role of a response and we are interested in explaining their behavior using the other variables , and unsupervised dimension reduction where no distinction like this is made and all variables are considered equal. In this thesis the theory behind three linear dimension reduction methods, the principal component analysis (PCA), independent component analysis (ICA) and sliced inverse regression (SIR) is reviewed. Although both PCA and ICA are unsupervised methods, their criteria in creating the new variables differ to an extent making them suitable in different situations. The third method, SIR, is supervised and thus aims to replace the original explanatory variables with a smaller number of variables that best explain the variability of some response. Additionally, a variant of SIR that uses splines in finding the new variables is briefly discussed. The concept of simultaneous diagonalization of two scatter matrices is also given some thought. A relatively new method, the importance of the diagonalization for dimension reduction stems from the fact that most dimension reduction methods, while seemingly disconnected, can be formulated in a unified way using it. In the final section two simulation studies are conducted. In the first the performances of the two unsupervised methods (PCA and ICA) in finding directions relevant to explaining a response variable in a regression situation are compared to that of the supervised SIR. In the second simulation the superiority of the spline-using SIR to the regular SIR under some specific models is demonstrated.
Toll-Like Receptor 3 Is a Negative Regulator of Embryonic Neural Progenitor Cell Proliferation

Toll-like receptors (TLRs) play important roles in innate immunity. Several TLR family members have recently been shown to be expressed by neurons and glial cells in the adult brain, and may mediate responses of these cells to injury and infection. To address the possibility that TLRs play a functional role in development of the nervous system, we analyzed the expression of TLRs during different stages of mouse brain development and assessed the role of TLRs in cell proliferation. TLR3 protein is present in brain cells in early embryonic stages of development, and in cultured neural stem/progenitor cells (NPC). NPC from TLR3-deficient embryos formed greater numbers of neurospheres compared with neurospheres from wild-type embryos. Numbers of proliferating cells, as assessed by phospho histone H3 and proliferating cell nuclear antigen labeling, were also increased in the developing cortex of TLR3-deficient mice compared with wild-type mice in vivo. Treatment of cultured embryonic cortical neurospheres with a TLR3 ligand (polyIC) significantly reduced proliferating (BrdU-labeled) cells and neurosphere formation in wild type but not TLR3−/−-derived NPCs. Our findings reveal a novel role for TLR3 in the negative regulation of NPC proliferation in the developing brain.
Negative Influence of a Long-Term High-Fat Diet on Murine Bone Architecture

A correlation between obesity and bone metabolism is strongly assumed because adipocytes and osteoblasts originate from the same precursor cells and their differentiation is conversely regulated by the same factors. It is controversially discussed if obesity protects bone or leads to loss of bone mass. Thus, the aim of the present study was to investigate the influence of diet-induced mild obesity (11% increased body weight compared to control) on bone microstructure in mice. Four-week-old male C57BL/6J mice received a high-fat diet (HFD, 60% kcal from fat) and were analyzed by means of dual X-ray absorptiometry, histological methods, real-time RT-PCR, and transmission electron microscopy in comparison to control animals (10% kcal from fat). The cancellous bone mass, collagen 1α1 expression, amount of osteoid, and cohesion of cells via cell-to-cell contacts decreased in HFD mice whereas the bone mineral density and the amount of osteoblasts and osteoclasts were not modified. The amount of apoptotic osteocytes was increased in HFD mice in comparison to controls. We conclude that moderately increased body weight does not protect bone architecture from age-dependent degeneration. By contrast, bone microstructure is negatively affected and reduced maintenance of cell-cell contacts may be one of the underlying mechanisms.
Assessing Forward-, Reverse-, and Average-Entailer Indices on Natural Language Input from the Intelligent Tutoring System, iSTART

This study reports on an experiment that analyzes a variety of entailment evaluations provided by a lexico-syntactic tool, the Entailer. The environment for these analyses is from a corpus of self-explanations taken from the Intelligent Tutoring System, iSTART. The purpose of this study is to examine how evaluations of hand-coded entailment, paraphrase, and elaboration compare to various evaluations provided by the Entailer. The evaluations include standard entailment (forward) as well as the new indices of Reverseand Average-Entailment. The study finds that the Entailer’s indices match or surpass human evaluators in making textual evaluations. The findings have important implications for providing accurate and appropriate feedback to users of Intelligent Tutoring Systems.
Antinociceptive Pharmacology of N-[[4-(4,5-Dihydro-1H-imidazol-2-yl)phenyl]methyl]-2-[2-[[(4-methoxy-2,6-dimethylphenyl) sulfonyl]methylamino]ethoxy]-N-methylacetamide, Fumarate (LF22-0542), a Novel Nonpeptidic Bradykinin B1 Receptor Antagonist

The antinociceptive pharmacology of N-[[4-(4,5-dihydro-1H-imidazol-2-yl)phenyl]methyl]-2-[2-[[(4-methoxy-2,6-dimethylphenyl) sulfonyl]methylamino]ethoxy]-N-methylacetamide fumarate (LF22-0542), a novel nonpeptidic B1 antagonist, was characterized. LF22-0542 showed high affinity for human and mouse B1 receptors with virtually no affinity for the human B2 receptor; a selectivity index of at least 4000 times was obtained when LF22-0542 was profiled throughout binding or cell biology assays on 64 other G-protein-coupled receptor, 10 ion channels, and seven enzymes. LF22-0542 was a competitive B1 receptor antagonist and elicited significant antinociceptive actions in the mouse acetic acid-induced writhing assay, as well as in the second phases of formalin-induced nociception in mice and in both the first and second phases of the formalin response in rats. LF22-0542 was active after s.c. but not p.o. administration. In B1 receptor knockout (KO) mice, acetic acid and formalin responses were significantly reduced and LF22-0542 had no additional effects in these animals. LF22-0542 alleviated thermal hypersensitivity in both acute (carrageenan) and persistent inflammatory (complete Freund's adjuvant) pain models in rats. LF22-0542 produced a full reversal of experimental neuropathic thermal hypersensitivity but was inactive in reversing nerve injury-induced tactile hypersensitivity in rats. In agreement with this observation, B1 KO mice subjected to peripheral nerve injury did not show thermal hypersensitivity but developed nerve injury-induced tactile hypersensitivity normally. The data demonstrate the antihyperalgesic actions of a selective systemically administered B1 receptor antagonist and suggest the utility of this class of agents for the treatment of inflammatory pain states and for some aspects of neuropathic pain.
Effects of the Gap Junction Modifier Rotigaptide (ZP123) on Atrial Conduction and Vulnerability to Atrial Fibrillation

Background— Altered conduction is associated with increased atrial fibrillation (AF) vulnerability in canine models of chronic mitral regurgitation (MR) and heart failure (HF). Rotigaptide (ZP123) augments gap junction conductance, improving cell-to-cell coupling. We studied the effects of rotigaptide on atrial conduction and AF vulnerability in the canine MR and HF models. Methods and Results— Twenty-one dogs in 3 groups were studied: control (n=7), chronic MR induced by mitral avulsion (n=7), and HF induced by ventricular tachypacing (n=7). Epicardial mapping of both atria was performed with a 512-electrode array at baseline and at increasing rotigaptide doses (10, 50, and 200 nmol/L). Conduction velocity increased in both atria in control animals and MR animals (maximum percentage increase: 24±5%, 38±6% [P<0.001, <0.001] in the left atrium and 19±9%, 18±3% [P<0.001, <0.001] in the right atrium). Conduction velocity did not change in the left atrium of the HF group and increased minimally in the right atrium (3±3%, 17±5% [P=NS, P=0.001]). AF duration was increased at baseline in MR and HF animals (control: 16±25 seconds, MR: 786±764 seconds, HF: 883±684 seconds; P=0.013). At 50 nmol/L of rotigaptide, duration of AF markedly decreased in the MR animals (96% reduction, P<0.001), reducing AF duration to that of control animals (control: 9±11 seconds, MR: 14±16 seconds, HF: 1622±355 seconds; P=0.04). Conclusions— Gap junction modulation with rotigaptide reduces AF vulnerability in a canine MR model of AF to a level similar to control animals but does not affect AF vulnerability in the canine HF model. This may be a novel therapeutic target in some forms of AF.