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Search Results: 1 - 10 of 170439 matches for " Michelle E. Legaspi "
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European Corn Borer (Ostrinia nubilalis) Induced Responses Enhance Susceptibility in Maize
Nicole J. Dafoe, James D. Thomas, Paul D. Shirk, Michelle E. Legaspi, Martha M. Vaughan, Alisa Huffaker, Peter E. Teal, Eric A. Schmelz
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0073394
Abstract: Herbivore-induced plant responses have been widely described following attack on leaves; however, less attention has been paid to analogous local processes that occur in stems. Early studies of maize (Zea mays) responses to stem boring by European corn borer (ECB, Ostrinia nubilalis) larvae revealed the presence of inducible acidic diterpenoid phytoalexins, termed kauralexins, and increases in the benzoxazinoid 2-hydroxy-4,7-dimethoxy-1,4-benzoxazin-3?-one-glucose(HDMBOA-Glc) after 24 h of herbivory. Despite these rapidly activated defenses, larval growth was not altered in short-term feeding assays. Unexpectedly, ECB growth significantly improved in assays using stem tissue preconditioned by 48 h of larval tunneling. Correspondingly, measures of total soluble protein increased over 2.6-fold in these challenged tissues and were accompanied by elevated levels of sucrose and free linoleic acid. While microarray analyses revealed up-regulation of over 1100 transcripts, fewer individual protein increases were demonstrable. Consistent with induced endoreduplication, both wounding and ECB stem attack resulted in similar significant expansion of the nucleus, nucleolus and levels of extractable DNA from challenged tissues. While many of these responses are triggered by wounding alone, biochemical changes further enhanced in response to ECB may be due to larval secreted effectors. Unlike other Lepidoptera examined, ECB excrete exceedingly high levels of the auxin indole-3-acetic acid (IAA) in their frass which is likely to contact and contaminate the surrounding feeding tunnel. Stem exposure to a metabolically stable auxin, such as 2,4-dichlorophenoxyacetic acid (2,4-D), promoted significant protein accumulation above wounding alone. As a future testable hypothesis, we propose that ECB-associated IAA may function as a candidate herbivore effector promoting the increased nutritional content of maize stems.
The nightmare of a painful phantom
J. Manuel Ortega Legaspi
Salud mental , 2007,
Abstract: El dolor es representado en el Sistema Nervioso Central en algunas de las estructuras más antiguas desarrolladas a lo largo de la historia filogenética. Además, es el síntoma más importante por el que los pacientes buscan atención médica. Sin embargo, existen patologías en las que el dolor deja de ser la alarma y se convierte en un problema médico; probablemente el ejemplo más dramático sea la presencia de dolor en una parte del cuerpo que no está presente, esto se conoce como miembro fantasma doloroso . A lo largo de la historia, se ha prestado mucha atención en el entendimiento del dolor por renombradas personalidades. El miembro fantasma fue descrito por primera vez por Ambroise Paré en el siglo XVI; en el siglo XIX hizo lo mismo Silas Weir Mitchell, y posteriormente fue revisado con mayor profundidad por Livingston a inicios del siglo XX. El fenómeno del miembro fantasma no doloroso es reportado prácticamente por todas las personas amputadas, y el doloroso en 50 a 80% de los casos, sin importar la naturaleza de la amputación. Nos encontramos frente un importante problema de salud pública. La principal causa de amputación de miembros viene de las complicaciones vasculares y neuropáticas de la diabetes, seguida en frecuencia por causas traumáticas, extremadamente frecuentes en la población económicamente activa. Una causa preocupante de trauma y del fantasma en algunos países en desarrollo son las minas anti-persona. Estas, llevan a los afectados, la mayoría civiles con un número considerable de ni os, a un infierno viviente acompa ado de un fantasma doloroso. El dolor por miembro fantasma representa un desafío que involucra un enorme campo de estudio relacionado con la salud pública y las neurociencias. Es una entidad que involucra factores periféricos, centrales y psicológicos. La investigación neurocientífica ha estudiado el Sistema desde el nervio periférico amputado donde se forma un neuroma, hasta la corteza cerebral en donde hay una activación disminuida del área que representa al miembro amputado en la corteza somatosensorial después de una amputación. Además, esto ha provocado el desarrollo de teorías como la neuromatriz . En este sentido, la corteza anterior del cíngulo ha sido propuesta como una estructura clave en el desarrollo de la nocicepción fantasma en animales. Después de una gran cantidad de investigación, sólo 30% de los pacientes se ve beneficiado, gracias a un buen número de intervenciones. El dolor por miembro fantasma es un ejemplo claro de que la conciencia se puede enfermar y la frecuencia clínica, la importancia y la trasc
Marine Renewable Energy Policy: Some US and International Perspectives Compared
Michelle E. Portman
Oceanography , 2010,
Abstract: This article describes the policy framework for siting, permitting, and developing offshore renewable energy facilities in the United States. It also highlights features of regulatory programs in other countries and makes some comparisons. Initially, the article presents a brief historical background of US regulatory development, and then it provides a synopsis of the more salient features of the federal siting and permitting program, followed by descriptions of policy frameworks in three other countries—the United Kingdom, Germany, and Portugal. It concentrates on federal policies as set apart from state and local-level policies, on policies encouraging or authorizing construction of offshore facilities, and on those offshore energy technologies considered relevant in the short term by the Alternative Energy and Alternative Use Program of the Minerals Management Service. These hydrokinetic energy sources are generated in or over submerged lands and include offshore wind energy. To facilitate comparisons, framework elements are categorized as: (1) research and innovation policies that help to develop emerging and improved technologies; (2) market-based policies that underwrite the cost of introducing technologies, provide a competitive framework, and may internalize externalities; and (3) regulatory advances that simplify and improve the efficiency of permitting offshore energy facilities.
Small-Scale Spatial Patterns of Copernicia alba Morong near Bahia Negra, Paraguay  [PDF]
Michelle E. Cisz, Michael J. Falkowski, Blair Orr
Natural Resources (NR) , 2013, DOI: 10.4236/nr.2013.45045
Abstract:

We assessed the spatial distribution of Copernicia alba Morong. In the study area, a lowland palm savanna floodplain, C. alba is the only overstory species. We hypothesized C. alba would be randomly distributed within natural stands. Palms were tallied in six randomly located 0.25 haplots and analyzed using a first-order, Ripley’s K function to assess the distribution of juvenile, adult, and total palm populations. While the total population had either aggregated or random distributions, when analyzing juvenile and adult population separately, we found juveniles were consistently more aggregated than the adults.

The association between population aging and oral and pharynx cancer incidence in the American continent
Michelle E. Denison,Libia Soto
Colombia Médica , 2011,
Abstract: Objective: The objective of this study was to explore the association between aging of population and incidence of oral cavity and pharynx cancer at the country level in the American continent.Methods: An ecological study at the country level. Countries’ data for oral cavity and pharynx cancer incidence comes from the International Agency for Cancer Research (GLOBOCAN 2002). Twenty eight countries were included from North America, Central America, and South America. The dependent variables were the countries’ oral cavity and pharynx cancer incidence rates (per 100,000/ year) by sex, overall and age-specific groups, 0-64 (younger population) and 65+ (older population), and the main independent variable was the countries’ aging population (% of persons 65 years and older). Other variables considered were per-capita gross national income and prevalence of smoking by sex at the country level.Results: Overall countries’ level of oral cavity and pharynx cancer incidence rates were strongly correlated with the countries’ aging population (p<0.01). In adjusted regression analyses, the countries’ aging population was significantly associated with overall oral cavity and pharynx cancer incidence rates for male (p<0.0001, p=0.0003) and female (p=0.0025, p=0.0134) populations.Conclusion: Countries’ aging population was associated with increased countries’ oral cavity and pharynx cancer incidence rates in the American continent.
Multivesicular Release Underlies Short Term Synaptic Potentiation Independent of Release Probability Change in the Supraoptic Nucleus
Michelle E. Quinlan, Michiru Hirasawa
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0077402
Abstract: Magnocellular neurons of the supraoptic nucleus receive glutamatergic excitatory inputs that regulate the firing activity and hormone release from these neurons. A strong, brief activation of these excitatory inputs induces a lingering barrage of tetrodotoxin-resistant miniature EPSCs (mEPSCs) that lasts for tens of minutes. This is known to accompany an immediate increase in large amplitude mEPSCs. However, it remains unknown how long this amplitude increase can last and whether it is simply a byproduct of greater release probability. Using in vitro patch clamp recording on acute rat brain slices, we found that a brief, high frequency stimulation (HFS) of afferents induced a potentiation of mEPSC amplitude lasting up to 20 min. This amplitude potentiation did not correlate with changes in mEPSC frequency, suggesting that it does not reflect changes in presynaptic release probability. Nonetheless, neither postsynaptic calcium chelator nor the NMDA receptor antagonist blocked the potentiation. Together with the known calcium dependency of HFS-induced potentiation of mEPSCs, our results imply that mEPSC amplitude increase requires presynaptic calcium. Further analysis showed multimodal distribution of mEPSC amplitude, suggesting that large mEPSCs were due to multivesicular glutamate release, even at late post-HFS when the frequency is no longer elevated. In conclusion, high frequency activation of excitatory synapses induces lasting multivesicular release in the SON, which is independent of changes in release probability. This represents a novel form of synaptic plasticity that may contribute to prolonged excitatory tone necessary for generation of burst firing of magnocellular neurons.
Functional connectivity studies of patients with auditory verbal hallucinations
Ralph E. Hoffman,Michelle Hampson
Frontiers in Human Neuroscience , 2012, DOI: 10.3389/fnhum.2012.00006
Abstract: Functional connectivity (FC) studies of brain mechanisms leading to auditory verbal hallucinations (AVHs) utilizing functional magnetic resonance imaging (fMRI) data are reviewed. Initial FC studies utilized fMRI data collected during performance of various tasks, which suggested frontotemporal disconnection and/or source-monitoring disturbances. Later FC studies have utilized resting (no-task) fMRI data. These studies have produced a mixed picture of disconnection and hyperconnectivity involving different pathways associated with AVHs. Results of our most recent FC study of AVHs are reviewed in detail. This study suggests that the core mechanism producing AVHs involves not a single pathway, but a more complex functional loop. Components of this loop include Wernicke's area and its right homologue, the left inferior frontal cortex, and the putamen. It is noteworthy that the putamen appears to play a critical role in the generation of spontaneous language, and in determining whether auditory stimuli are registered consciously as percepts. Excessive functional coordination linking this region with the Wernicke's seed region in patients with schizophrenia could, therefore, generate an overabundance of potentially conscious language representations. In our model, intact FC in the other two legs of corticostriatal loop (Wernicke's with left IFG, and left IFG with putamen) appeared to allow hyperconnectivity linking the putamen and Wernicke's area (common to schizophrenia overall) to be expressed as conscious hallucinations of speech. Recommendations for future studies are discussed, including inclusion of multiple methodologies applied to the same subjects in order to compare and contrast different mechanistic hypotheses, utilizing EEG to better parse time-course of neural synchronization leading to AVHs, and ascertaining experiential subtypes of AVHs that may reflect distinct mechanisms.
Pruning Bayesian Networks for Efficient Computation
Michelle Baker,Terrance E. Boult
Computer Science , 2013,
Abstract: This paper analyzes the circumstances under which Bayesian networks can be pruned in order to reduce computational complexity without altering the computation for variables of interest. Given a problem instance which consists of a query and evidence for a set of nodes in the network, it is possible to delete portions of the network which do not participate in the computation for the query. Savings in computational complexity can be large when the original network is not singly connected. Results analogous to those described in this paper have been derived before [Geiger, Verma, and Pearl 89, Shachter 88] but the implications for reducing complexity of the computations in Bayesian networks have not been stated explicitly. We show how a preprocessing step can be used to prune a Bayesian network prior to using standard algorithms to solve a given problem instance. We also show how our results can be used in a parallel distributed implementation in order to achieve greater savings. We define a computationally equivalent subgraph of a Bayesian network. The algorithm developed in [Geiger, Verma, and Pearl 89] is modified to construct the subgraphs described in this paper with O(e) complexity, where e is the number of edges in the Bayesian network. Finally, we define a minimal computationally equivalent subgraph and prove that the subgraphs described are minimal.
Administration of Fozivudine Tidoxil as a Single-Agent Therapeutic during Acute Feline Immunodeficiency Virus Infection Does Not Alter Chronic Infection
Michelle M. Miller,Jonathan E. Fogle
Viruses , 2012, DOI: 10.3390/v4060954
Abstract: Initiating combination antiretroviral therapy (ART) during acute HIV infection has been correlated with decreased viral set point and improved lymphocyte function. However, the long term effects of single-agent therapy administered only during the acute stage of infection (interrupted treatment) remain largely uncharacterized. In this study we provide longitudinal data using the feline immunodeficiency virus (FIV) model for HIV infection. Infected cats were treated with a prophylactic single-agent therapy, Fozivudine tidoxil (FZD), for six weeks, starting one day before infection. The initial acute infection study, reported elsewhere, demonstrated a decrease in plasma- and cell-associated viremia at two weeks post-infection (PI) in FZD-treated cats as compared to placebo-treated cats. We hypothesized that this early alteration in plasma- and cell-associated viremia would alter the virus set point and ultimately affect the outcome of chronic infection. Here we provide data at one, two and three years PI for plasma- and/or cell-associated viremia, total lymphocyte counts and CD4:CD8 ratios. There was no difference in viremia or cell counts between treated and nontreated groups at all time points tested. Contrary to our hypothesis, these results suggest that treatment with a single agent anti-retroviral drug during acute lentivirus infection does not significantly alter viral load and immune function during the chronic, asymptomatic stage of infection.
Habilidades sociais na agorafobia e fobia social
Levitan, Michelle;Rangé, Bernard;Nardi, Antonio E.;
Psicologia: Teoria e Pesquisa , 2008, DOI: 10.1590/S0102-37722008000100011
Abstract: anxiety disorders are commonly associated to social skills deficits. social phobia is often related to this deficit, while agoraphobia is not considered. the purpose of this review is to investigate the literature on this association. an electronic search was conducted in the following databases: psycinfo, medline and scielo, besides the references of some selected articles. social skills deficit were more frequent in the studies that evaluated the performance of anxious individuals on unstructured tasks. agoraphobia appears to be associated to an assertiveness deficit, although few studies were conducted.
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