474 research outputs found
Cost-effective HPC clustering for computer vision applications
We will present a cost-effective and flexible realization of high performance computing (HPC) clustering and its potential in solving computationally intensive problems in computer vision. The featured software foundation to support the parallel programming is the GNU parallel Knoppix package with message passing interface (MPI) based Octave, Python and C interface capabilities. The implementation is especially of interest in applications where the main objective is to reuse the existing hardware infrastructure and to maintain the overall budget cost. We will present the benchmark results and compare and contrast the performances of Octave and MATLAB
Bioengineered Nisin A Derivatives with Enhanced Activity against Both Gram Positive and Gram Negative Pathogens
peer-reviewedNisin is a bacteriocin widely utilized in more than 50 countries as a safe and natural antibacterial food preservative. It is the most extensively studied bacteriocin, having undergone decades of bioengineering with a view to improving function and physicochemical properties. The discovery of novel nisin variants with enhanced activity against clinical and foodborne pathogens has recently been described. We screened a randomized bank of nisin A producers and identified a variant with a serine to glycine change at position 29 (S29G), with enhanced efficacy against S. aureus SA113. Using a site-saturation mutagenesis approach we generated three more derivatives (S29A, S29D and S29E) with enhanced activity against a range of Gram positive drug resistant clinical, veterinary and food pathogens. In addition, a number of the nisin S29 derivatives displayed superior antimicrobial activity to nisin A when assessed against a range of Gram negative food-associated pathogens, including E. coli, Salmonella enterica serovar Typhimurium and Cronobacter sakazakii. This is the first report of derivatives of nisin, or indeed any lantibiotic, with enhanced antimicrobial activity against both Gram positive and Gram negative bacteria.This work was supported by the Irish Government under the National Development Plan, through Science Foundation Ireland Investigator awards (10/IN.1/B3027) and (06/IN.1/B98) (http://www.sfi.ie)
The El Niño - Southern Oscillation, rainfall and wheat yields in South Africa
This thesis assesses the relationships between the El Niño-Southern Oscillation (ENSO), rainfall and South African commercial winter wheat yields from 1974 - 2000. The analysis is through a combination of the Pearson's product moment correlation coefficient and an assessment of the magnitude and consistency of rainfall and wheat anomalies in the year of, and the year following warm (El Niño) and cold (La Niña) ENSO events. The ENSO - rainfall relationship is analysed on timescales from 1 - 24 months and this study finds that there are more unusually dry and unusually wet months during El Niño events than during La Niña episodes (where dry and wet months are <75°/o and over 25~·'0 more than the 1921 - 2000 mean, respectively) and these conditions are consistently found in some rainfall areas during each El Niño or La Niño event; there is marked inter - El Niño and inter La Niña variation in late summer and annual rainfall; and that there has been a significant shift in the timings of maximum rainfall anomalies during El Niño episodes from an earlier investigation. The effects of rainfall on the wheat yield vary spatially, but are most apparent in the Free State where severe droughts have resulted in reduced yields. In the Northern Cape and Western Cape anomalously wet conditions, especially in late summer, coincide with reduced wheat yields. The ENSO - wheat yield relationship is not a simple linear one, and despite yields in the Northern Cape and Western Cape tracking Pacific sea surface temperatures by nearly a year, El Niño and La Niña years are not synonymous With increased or decreased yields in any province. ln fact, maximum and minimum yields in the Free State and Northern Cape are found in the year of, or year following a La Niño event, and consequently the present predictability of wheat yields by ENSO is limited. The relationships between ENSO, rainfall and wheat yield in South Africa is not readily apparent, which may be due to the short (<30 years) data set or mediating factors outside this study such as farm - management strategies or hemispheric variation in the evolution of El Niño and La Niña events
The Synthesis of 2, 11-Dithiabenzo - [3.3] - Paracyclophane and an Octadeutero Derivative
The purpose of this work was the synthesis of 2, 11 -dithia-benzo- [3.3] -paracyclophane and its octadeutero derivative 2,11-dithia- 3,3, 5, 6, 8, 9, 10, 10-octadeutero-benzo - [3.3] paracyclophane. A comparison of their nuclear magnetic resonance spectra as well as their mass spectra will unequivocably provide proof of their successful synthesis
Values and Leadership: Theory Development, New Research, and an Agenda for the Future
This article presents an updated account of values and valuation processes as they occur in school settings. A tradition of epistemological and philosophical debate, as well as the dominance of empiricist perspectives in educational administration, have tended to separate the consideration of values as influences on leadership practices from the usual organizational or social collective perspectives common to the field. More recently, however, powerful social forces such as globalization and the increasing diversity of our societies have stimulated increased academic productivity in this sector. A more balanced view of values as an influence on administration is emerging, which combines notions of the personal values manifested by individuals and the professional values of administration with the collective values manifested by groups, societies, and organizations. Discussion and inquiry have now extended beyond the usual expert opinion and academic debate of theorists and philosophers to include practitioners, empirical verifications of theory, and important new research findings. In this article key concepts from theory and a selection of findings from research are reviewed. The application of theory and research about values through reflective educational practice is discussed. Certain methodological problems associated with values research are examined, and the ground breaking work of several key contributors to the field is identified and considered. The article concludes with some speculations on an agenda for future theory-building and research in the values field.Cet article présente une mise à jour des valeurs et du processus d'évaluation tels qu'ils se manifestent dans les milieux scolaires. Une tradition de débats épistémologiques et philosophiques, conjuguée à la dominance de perspectives empiristes en administration pédagogique, a fait en sorte que l'on a eu tendance à écarter l'interprétation des valeurs selon laquelle celles-ci agissent comme influences sur les pratiques administratives des perspectives collectives organisationnelles ou sociales couramment associées au domaine. Plus récemment par contre, des forces sociales puissantes telles la globalisation et la diversité croissante de nos sociétés ont stimulé une production académique accrue dans ce secteur. Défait, une vision plus équilibrée des valeurs comme facteurs ayant une influence sur l'administration commence à se faire sentir. Cette vision combine les valeurs personnelles qu'affichent les individus, les valeurs professionnelles d'une administration ainsi que les valeurs collectives manifestées par les groupes, les sociétés et les organisations. Les discussions et les enquêtes menées par les opinions d'experts et les débats académiques de théoriciens et philosophes englobent maintenant également les avis de praticiens, des vérifications empiriques de la théorie ainsi que d'importants nouveaux résultats de recherche. L'article passe en revue des concepts théoriques clés et une sélection de résultats de recherche. On y discute également l'application de la théorie et de la recherche portant sur les valeurs à la pratique pédagogique réfléchie. Suivent un examen de certains problèmes méthodologiques associés à la recherche sur les valeurs et une étude du travail révolutionnaire de plusieurs chercheurs clés du domaine. Des hypothèses quant à l'agenda qui guiderait la création de théories et l'orientation de la recherche sur les valeurs terminent l'article
Dopamine D_2-receptor activation elicits akinesia, rigidity, catalepsy, and tremor in mice expressing hypersensitive 4 nicotinic receptors via a cholinergic-dependent mechanism
Recent studies suggest that high-affinity neuronal nicotinic acetylcholine receptors (nAChRs) containing α4 and β2 subunits (α4β2*) functionally interact with G-protein-coupled dopamine (DA) D_2 receptors in basal ganglia. We hypothesized that if a functional interaction between these receptors exists, then mice expressing an M2 point mutation (Leu9'Ala) rendering 4 nAChRs hypersensitive to ACh may exhibit altered sensitivity to a D_2-receptor agonist. When challenged with the D_(2)R agonist, quinpirole (0.5–10 mg/kg), Leu9'Ala mice, but not wild-type (WT) littermates, developed severe, reversible motor impairment characterized by rigidity, catalepsy, akinesia, and tremor. While striatal DA tissue content, baseline release, and quinpirole-induced DA depletion did not differ between Leu9'Ala and WT mice, quinpirole dramatically increased activity of cholinergic striatal interneurons only in mutant animals, as measured by increased c-Fos expression in choline acetyltransferase (ChAT)-positive interneurons. Highlighting the importance of the cholinergic system in this mouse model, inhibiting the effects of ACh by blocking muscarinic receptors, or by selectively activating hypersensitive nAChRs with nicotine, rescued motor symptoms. This novel mouse model mimics the imbalance between striatal DA/ACh function associated with severe motor impairment in disorders such as Parkinson’s disease, and the data suggest that a D_(2)R–α4*-nAChR functional interaction regulates cholinergic interneuron activity.—Zhao-Shea, R., Cohen, B. N., Just, H., McClure-Begley, T., Whiteaker, P., Grady, S. R., Salminen, O., Gardner, P. D., Lester, H. A., Tapper, A. R. Dopamine D2-receptor activation elicits akinesia, rigidity, catalepsy, and tremor in mice expressing hypersensitive α4 nicotinic receptors via a cholinergic-dependent mechanism
Chronic Nicotine Cell Specifically Upregulates Functional α4* Nicotinic Receptors: Basis for Both Tolerance in Midbrain and Enhanced Long-Term Potentiation in Perforant Path
Understanding effects of chronic nicotine requires identifying the neurons and synapses whose responses to nicotine itself, and to endogenous acetylcholine, are altered by continued exposure to the drug. To address this problem, we developed mice whose α4 nicotinic receptor subunits are replaced by normally functioning fluorescently tagged subunits, providing quantitative studies of receptor regulation at micrometer resolution. Chronic nicotine increased α4 fluorescence in several regions; among these, midbrain and hippocampus were assessed functionally. Although the midbrain dopaminergic system dominates reward pathways, chronic nicotine does not change α4* receptor levels in dopaminergic neurons of ventral tegmental area (VTA) or substantia nigra pars compacta. Instead, upregulated, functional α4* receptors localize to the GABAergic neurons of the VTA and substantia nigra pars reticulata. In consequence, GABAergic neurons from chronically nicotine-treated mice have a higher basal firing rate and respond more strongly to nicotine; because of the resulting increased inhibition, dopaminergic neurons have lower basal firing and decreased response to nicotine. In hippocampus, chronic exposure to nicotine also increases α4* fluorescence on glutamatergic axons of the medial perforant path. In hippocampal slices from chronically treated animals, acute exposure to nicotine during tetanic stimuli enhances induction of long-term potentiation in the medial perforant path, showing that the upregulated α4* receptors in this pathway are also functional. The pattern of cell-specific upregulation of functional α4* receptors therefore provides a possible explanation for two effects of chronic nicotine: sensitization of synaptic transmission in forebrain and tolerance of dopaminergic neuron firing in midbrain
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Exploring the effectiveness of an integrated exercise/CBT intervention for young men's mental health
Objective. This pilot study investigated the effectiveness of a team-based sport/psychosocial intervention (Back of the Net, BTN) with an individual exercise (IE) and a control condition for the mental health of young men.
Design. Ten-week randomized control trial and eight-week post-intervention follow-up.
Methods. A total of 104 sedentary males aged between 18 and 40 years were recruited and randomly assigned to the BTN, IE, or a control condition. The BTN programme integrated team sport (i.e., football) and cognitive-behavioural techniques. IE sessions included aerobic and resistance training. The control group refrained from exercise. Participants completed the Beck Depression Inventory – 2nd Edition (BDI-II), the Social Provisions Scale (SPS) and a short qualitative questionnaire at pre-intervention, week 5, post-intervention and at 8-week follow-up.
Results. Participants in both the BTN and the IE condition demonstrated a significant decrease in BDI-II scores compared to the control condition at post-intervention and at 8-week follow-up. The IE condition demonstrated significantly greater perceived social support than the BTN condition at week 5 and the control group at 8-week follow-up. Qualitative data support the main empirical findings.
Conclusion. Exercise-based interventions were effective in reducing symptoms of depression in a non-clinical community sample of young men. The BTN programme demonstrated potential for improving the mental health of young men however larger scale community-based research is warranted to further examine the effectiveness of this type of intervention
African American Genealogical Research
This document contains information related to conducting research for African American genealogy, especially in the state of South Carolina. Guidebooks, post-emancipation records and statistics, census records, militia enrollments and more are recommended in detail throughout the booklet
Potential Use of Biotherapeutic Bacteria to Target Colorectal Cancer-Associated Taxa
peer-reviewedThe role of the gut microbiome in human health and disease is the focus of much attention. It has been widely agreed upon that our gut bacteria play a role in host immunity, nutrient absorption, digestion, metabolism, and other key drivers of health. Furthermore, certain microbial signatures and specific taxa have also been associated with the development of diseases, such as obesity; inflammatory bowel disease; and, indeed, colorectal cancer (CRC), which is the focus of this review. By extension, such taxa represent potential therapeutic targets. In particular, the emerging human pathogen Fusobacterium nucleatum represents an important agent in CRC development and its control within the gastrointestinal tract is desirable. This paper reviews the principal bacterial pathogens that have been associated with CRC to date and discusses the in vitro and human studies that have shown the potential use of biotherapeutic strains as a means of targeting CRC-associated bacteria
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