377 research outputs found

    Spatio-temporal distribution of the infestations of Coelaenomenodera lameensis Berti and Mariau (Coleoptera, Chrysomelidae) an oil palm tree (Elaeis guineensis Jacq.) pest in Toumanguié (Côte d’Ivoire)

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    Spatio-temporal distribution of Coelaenomenodera lameensis Berti and Mariau, 1999, pest of palm oil tree (Elaeis guineensis Jacquin, 1963) was carried out on 1226 ha of an industrial plantation at Toumanguié (south-east of Côte d’Ivoire). Temporal distribution of population established the existence, according to the years, of favorable periods of Coelaenomenodera lameensis infestations. Eight peaks of infestation were observed during 24 months. Infestation cycles proceeds each 90 days. Spatial distribution of the infestations revealed experimental plots having recorded between 0 and 8 months of infestation during the 2 years of investigation. This distribution proved to be independent of the age of the plots. Infestations were also independent of abiotic factors (rainfall, temperature and relative humidity). Larvae at stages 1, 2, 3 and 4 are mostly responsible of the damages observed in the fields.Key words: Coelaenomenodera lameensis; Elaeis guineensis; spatio-temporal distribution; Côte d’Ivoir

    Visokotlačna tekućinska kromatografija s detektorom raspršenja svjetla u uparenom uzorku za određivanje količine glavnih razreda fosfolipida u magarećem serumu

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    An HPLC method with an evaporative laser scattering detector was used to quantify major phospholipids fractions in donkeys’ serum. Blood samples were collected bimonthly for a whole year from 20 donkeys (10 male and 10 female) from the Sudanese breed kept at the premises of the Central Veterinary Research Laboratory (CVRL), Soba. The method used made the excellent separation possible of phosphatidylglycerine (PG), phosphatidylethanolamine (PE), phosphatidylinositol (PI), phosphatidylcholine (PC), and sphingomyelin (SM). in 27 minutes, including the regeneration of the column. The SM resulted in two peaks (saturated and unsaturated fatty acids), as described by other researchers. The method was unable to separate phosphatidylserine (PS), which appeared in one peak with phosphatidylinositol. There is a signififi cant difference in the level of PG, PE, PI and SM between females and males.The method fully discussed in this study and the obtained values of major phospholipids can be used for health control and diagnosis of diseases.Visokotlačna tekućinska kromatografija s detektorom raspršenja svjetla u uparenom uzorku rabljena je za određivanje količine glavnih frakcija fosfolipida u magarećem serumu. Uzorci krvi bili su uzeti od 20 životinja (10 magaraca i 10 magarica sudanske pasmine) držanih u prostorima Središnjega veterinarskoga istraživačkoga laboratorija, Soba. Rabljena metoda omogućila je izvrsno odvajanje fosfatidilglicerola (FG), fosfatidiletanolamina (FE), fosfatidilinozitola (FI), fosfatidilkolina i sfifi ngomijelina (SM) za 27 minuta uključujući i regeneraciju kolone. Sfingomijelin je pokazivao dva vrška (zasićene i nezasićene masne kiseline) kao što je opisano od drugih autora. Rabljenom metodom nije se moglo odvojiti fosfatidilserin od fosfatidilinozitola. Ustanovljena je signifikantna razlika u razini FG, FE, FI i SM u mužjaka i ženki. U radu se iscrpno raspravlja o metodi, a dobivene vrijednosti glavnih fosfolipida mogu se upotrijebiti za kontrolu zdravlja i dijagnosticiranje bolesti

    Environmental Factors and Students\u27 Learning Approaches: a Survey on Malaysian Polytechnics Students

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    Several studies have shown the impact of environmental factors on student learning approaches. Despite the importance of such studies, studies on technical learners are few. Thus, this study aimed to determine the influence of learning environment on Polytechnics students\u27 learning approaches in Malaysia. Learning environment plays an important role in the cognitive, effective and social domains of students because it could improve students\u27 learning outcomes. Learning approaches refer to the ways students deal with academic tasks that are related to learning outcomes. This study used Course Experience Questionnaire (CEQ) and Revised Two-Factor Study Process Questionnaire (RSPQ-2F) to collect the research data. Data were analyzed using AMOS Version 18. Multiple regressions were conducted to predict learning environment factors that influenced the level of students\u27 learning approaches. The result shows that effective teaching is a major factor that influences students\u27 deep approach followed by the assessment, learning resources and clear objectives

    The upstream Variable Number Tandem Repeat polymorphism of the monoamine oxidase type A gene influences trigeminal pain-related evoked responses

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    Monoamines have an important role in neural plasticity, a key factor in cortical pain processing that promotes changes in neuronal network connectivity. Monoamine oxidase type A (MAOA) is an enzyme that, due to its modulating role in monoaminergic activity, could play a role in cortical pain processing. The X-linked MAOA gene is characterized by an allelic variant of length, the MAOA upstream Variable Number Tandem Repeat (MAOA-uVNTR) region polymorphism. Two allelic variants of this gene are known, the high-activity MAOA (HAM) and low-activity MAOA (LAM). We investigated the role of MAOA-uVNTR in cortical pain processing in a group of healthy individuals measured by the trigeminal electric pain-related evoked potential (tPREP) elicited by repeated painful stimulation. A group of healthy volunteers was genotyped to detect MAOA-uVNTR polymorphism. Electrical tPREPs were recorded by stimulating the right supraorbital nerve with a concentric electrode. The N2 and P2 component amplitude and latency as well as the N2-P2 inter-peak amplitude were measured. The recording was divided into three blocks, each containing 10 consecutive stimuli and the N2-P2 amplitude was compared between blocks. Of the 67 volunteers, 37 were HAM and 30 were LAM. HAM subjects differed from LAM subjects in terms of amplitude of the grand-averaged and first-block N2-P2 responses (HAM>LAM). The N2-P2 amplitude decreased between the first and third block in HAM subjects but not LAM subjects. The MAOA-uVNTR polymorphism seemed to influence the brain response in a repeated tPREP paradigm and suggested a role of the MAOA as a modulator of neural plasticity related to cortical pain processing

    Thermal simulation software outputs: a conceptual data model of information presentation for building design decision-making

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    Building simulation outputs are inherently complex and numerous. Extracting meaningful information from them requires knowledge which mainly resides only in the hands of experts. Initiatives to address this problem tend either to provide very constrained output data interfaces or leave it to the user to customize data organisation and query. This work proposes a conceptual data model from which meaningful dynamic thermal simulation information for building design decision-making may be constructed and presented to the user. It describes how the model was generated and can become operational, with examples of its applications to practical problems. The paper therefore contains useful information for software developers to help in specifying and designing simulation outputs which better respond to building designers’ needs

    Human hippocampal neurogenesis drops sharply in children to undetectable levels in adults.

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    New neurons continue to be generated in the subgranular zone of the dentate gyrus of the adult mammalian hippocampus. This process has been linked to learning and memory, stress and exercise, and is thought to be altered in neurological disease. In humans, some studies have suggested that hundreds of new neurons are added to the adult dentate gyrus every day, whereas other studies find many fewer putative new neurons. Despite these discrepancies, it is generally believed that the adult human hippocampus continues to generate new neurons. Here we show that a defined population of progenitor cells does not coalesce in the subgranular zone during human fetal or postnatal development. We also find that the number of proliferating progenitors and young neurons in the dentate gyrus declines sharply during the first year of life and only a few isolated young neurons are observed by 7 and 13 years of age. In adult patients with epilepsy and healthy adults (18-77 years; n = 17 post-mortem samples from controls; n = 12 surgical resection samples from patients with epilepsy), young neurons were not detected in the dentate gyrus. In the monkey (Macaca mulatta) hippocampus, proliferation of neurons in the subgranular zone was found in early postnatal life, but this diminished during juvenile development as neurogenesis decreased. We conclude that recruitment of young neurons to the primate hippocampus decreases rapidly during the first years of life, and that neurogenesis in the dentate gyrus does not continue, or is extremely rare, in adult humans. The early decline in hippocampal neurogenesis raises questions about how the function of the dentate gyrus differs between humans and other species in which adult hippocampal neurogenesis is preserved

    Direct imaging of the coexistence of ferromagnetism and superconductivity at the LaAlO3/SrTiO3 interface

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    LaAlO3 and SrTiO3 are insulating, nonmagnetic oxides, yet the interface between them exhibits a two-dimensional electron system with high electron mobility,1 superconductivity at low temperatures,2-6 and electric-field-tuned metal-insulator and superconductorinsulator phase transitions.3,6-8 Bulk magnetization and magnetoresistance measurements also suggest some form of magnetism depending on preparation conditions5,9-11 and suggest a tendency towards nanoscale electronic phase separation.10 Here we use local imaging of the magnetization and magnetic susceptibility to directly observe a landscape of ferromagnetism, paramagnetism, and superconductivity. We find submicron patches of ferromagnetism in a uniform background of paramagnetism, with a nonuniform, weak diamagnetic superconducting susceptibility at low temperature. These results demonstrate the existence of nanoscale phase separation as suggested by theoretical predictions based on nearly degenerate interface sub-bands associated with the Ti orbitals.12,13 The magnitude and temperature dependence of the paramagnetic response suggests that the vast majority of the electrons at the interface are localized, and do not contribute to transport measurements.3,6,7 In addition to the implications for magnetism, the existence of a 2D superconductor at an interface with highly broken inversion symmetry and a ferromagnetic landscape in the background suggests the potential for exotic superconducting phenomena.Comment: Edited version to appear in Nature Physic
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