3,086 research outputs found

    Association between gender and receipt of magnetic resonance imaging (MRI) in stroke patients from Puerto Rico

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    Introduction: Stroke is the fifth principal cause of death in the United States and Puerto Rico and a prime cause of adult disability. Women tend to have worse outcomes post-stroke. Initial diagnoses and management of stroke include the use of computed tomography (CT) and magnetic resonance image (MRI) scans. MRI scans are more sensitive and more specific than CT scans. Still, CT scans are used more commonly. Whether differences in the choice of imaging techniques exists for gender and whether that can be a potential reason for gender differences in post-stroke outcomes it is yet unknown. The study is directed to evaluate the association between gender and receipt of a MRI in stroke patients in the Puerto Rico population. Methods: We did a secondary analysis of data collected from patients who suffered from a stroke and who participated in the Puerto Rican Cardiovascular Surveillance System (PRCSS) in 2007, 2009 and 2011. The main independent variable was gender (male and female). The dependent variable will be receipt of a MRI (alone or in combination with any other imaging modality as recorded in the medical charts). Multivariate logistic regression was used to assess for the independent associations. P-value < 0.05 for a two tailed test was considered to be statistically significant. SPSS software was used for analysis. Results: A total of 1,950 patients suffered from an ischemic stroke and participated at the PRCSS. We excluded 595 patients due to BMI ≥35 (n=135) or no recorded BMI (n=460). MRI was used for 50% of participants. Women were 85% less likely to receive a MRI compared to men in both the unadjusted (OR-0.85, 95% CI=0.11-0.20, p-value <0.001) and after adjusting for BMI, age, marital status, hypertension, and transient ischemic attacks (TIA) (OR=0.15; 95%CI: 0.11-0.20). No other variables assessed had significant independent association with the receipt of a MRI. Conclusions: We found evidence of gender disparities in the receipt of MRI during hospitalization for stroke in patients in the Puerto Rico. Women were less likely to receive MRI compared to men. Further research on potential reasons for such dispairites, increasing awareness, and testing intervention as to decrease these potential disparities are needed

    Quantum State During and after O(4)O(4)-Symmetric Bubble Nucleation with Gravitaional Effects

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    We extend our previous analysis of the quantum state during and after O(4)O(4)-symmetric bubble nucleation to the case including gravitational effects. We find that there exists a simple relationship between the case with and without gravitational effects. In a special case of a conformally coupled scalar field which is massless except on the bubble wall, the state is found to be conformally equivalent to the case without gravity.Comment: 31 pages plain Tex file, uuencoded postscript figure file is available from [email protected] upon request, KUNS126

    Quimioesterilización de Anastrepha fraterculus (Diptera: Tephritidae) con un regulador del crecimiento de insectos

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    Anastrepha fraterculus is a fruit pest of economic importance in South America and northwestern Argentina. Currently, it is controlled with toxic baits but there is a demand for environmentally acceptable methodologies. The use of inhibitors of the chitin synthesis is proposed as a tool to sterilize adults in the field. The aim of this study was to evaluate the efficacy of different doses of lufenuron to generate chemosterilization in A. fraterculus. Three experiments were performed. In the first two, the product was incorporated into the diet of the adults from emergence to sexual maturity. Treated individuals from one sex were crossed with untreated individuals from the other sex. Eggs were collected and allowed embryonic development. In the third trial, untreated males and females were crossed and allowed to copulate. Subsequently, females were exposed to the product and the eggs were collected. Egg hatch was affected in the three experiments in a dose dependent way. In Experiment 3, the effect of the product was evidenced 48 hours after exposure. Fecundity was also affected when the females were the treated sex. The results show that exposure of adults to lufenuron reduces egg hatch in A. fraterculus encouraging further investigations to adapt this methodology for this species.Fil: Ruiz, J. E.. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; ArgentinaFil: Santilli, Melisa del Valle. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; ArgentinaFil: Cabrera, Debora Carina. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán; ArgentinaFil: Vera, M. T.. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán; ArgentinaFil: de la Vega, M. H.. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; Argentin

    Seasonal changes of ecophysiological responses of Hymenaea courbaril L.

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    The increase in the concentration of atmospheric CO2 and the likely associated climatic changes became a subject of most interest from several points of view. In Brazil, this issue is especially important due to the presence of the major tropical forests. Thus, it is important to produce scientific data about the native plants that could help to explain their role in the global carbon balance. It is obviously known that the photosynthetic process is key for this task and several experiments have been or are now being performed to understand the responses of plants to atmospheric CO2. In this work, we monitored the CO2 assimilation for 1 year, two times a week between 6am and 6pm with the aim to gather information on how Hymenaea courbaril responds during the four seasons in a year. Our results show that the higher assimilation rates occurred during the spring (the growing season) but that the periods during the day in which photosynthesis occurred were larger in the summer. A positive correlation (0.6) was observed between CO2 assimilation and the PPDF but no correlation was found with humidity. This is a large data set that describes in detail the photosynthesis related events during a whole year, which allowed the evaluation of the seasonal behaviour, a key approach to help understanding of carbon balance in the rain forest

    Vector Bin Packing with Multiple-Choice

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    We consider a variant of bin packing called multiple-choice vector bin packing. In this problem we are given a set of items, where each item can be selected in one of several DD-dimensional incarnations. We are also given TT bin types, each with its own cost and DD-dimensional size. Our goal is to pack the items in a set of bins of minimum overall cost. The problem is motivated by scheduling in networks with guaranteed quality of service (QoS), but due to its general formulation it has many other applications as well. We present an approximation algorithm that is guaranteed to produce a solution whose cost is about lnD\ln D times the optimum. For the running time to be polynomial we require D=O(1)D=O(1) and T=O(logn)T=O(\log n). This extends previous results for vector bin packing, in which each item has a single incarnation and there is only one bin type. To obtain our result we also present a PTAS for the multiple-choice version of multidimensional knapsack, where we are given only one bin and the goal is to pack a maximum weight set of (incarnations of) items in that bin

    Biomarkers in ringed seals reveal recent onset of borealization in the high- compared to the mid-latitude Canadian Arctic

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    This work resulted from the ARISE project (NE/P006035/1), part of the Changing Arctic Ocean program, funded by the UKRI Natural Environment Research Council (NERC).Warming of the Arctic has resulted in environmental and ecological changes, termed borealization, leading to the northward shift of temperate species. Borealization has occurred across all trophic levels, altering the structure of the food web. The onset and rate of borealization likely varies with latitude, depending on local warming and advection of warmer water into the Arctic. In order to assess latitudinal trends in food web structure in the Arctic, we analyzed stable nitrogen isotopes of specific amino acids alongside bulk stable carbon isotopes in ringed seal muscle tissue from the Canadian Arctic Archipelago (high-Arctic) and Southern Baffin Bay (mid-Arctic) from 1990 to 2016. Our results indicate a shift in food web structure in the high-Arctic that has occurred more recently when compared with the mid-Arctic. Specifically, over the past 25 years, the trophic position of ringed seals from the mid-Arctic was largely constant, whereas the trophic position of ringed seals decreased in the high-Arctic, reaching similar values observed in the mid-Arctic in 2015-2016. This suggests a potential shortening of the food chain length in the high-Arctic, possibly driven by changes in zooplankton communities feeding complexity in association with sea ice decline. This study identifies a temporal offset in the timing of borealization in the Canadian Arctic, resulting in different response of food webs to ecological changes, depending on latitude.Publisher PDFPeer reviewe

    Baseline data of four insecticides with different modes of action for Anastrepha fraterculus and Ceratitis capitata (Diptera: Tephritidae)

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    La mosca de la fruta del Mediterráneo, Ceratitis capitata (Wiedemann), y la mosca sudamericana de los frutos, Anastrepha fraterculus (Wiedemann) son plagas de gran importancia económica en Argentina y el mundo. Una de las formas de control es el uso de insecticidas en pulverizaciones totales o en cebos. El uso reiterado de un determinado producto ejerce una fuerte presión de selección, pudiendo ocasionar la aparición de resistencia. El objetivo de este trabajo fue determinar el dato de nivel básico de cuatro insecticidas con diferentes mecanismos de acción mediante bioensayos en laboratorio. Los productos utilizados fueron formulaciones comerciales de ciantraniliprol, clorpirifos, lambdacialotrina y spinosad. La concentración letal media se estimó mediante un análisis de la curva dosis-respuesta. Para ciantraniliprol y clorpirifós los machos y las hembras de ambas especies fueron igualmente susceptibles. Para lambdacialotrina se detectaron diferencias entre las dos especies; la CL50 de A. fraterculus (0,058 y 0,074 para machos y hembras respectivamente) fue menor que la de C. capitata (0,523 y 0,624 para machos y hembras respectivamente). Para spinosad, los machos de A. fraterculus fueron igualmente susceptibles que los machos y las hembras de C. capitata. Estos resultados generan valores de referencia para Argentina y evidencian la necesidad de completar este tipo de estudios con evaluaciones de poblaciones naturales sobre las cuales se ejerce control químico así como con ensayos en campo y semi-campo. Asimismo muestran la necesidad de completar este tipo de estudios con evaluaciones de los niveles de ingesta en las distintas concentraciones.The Mediterranean fruit fly, Ceratitis capitata (Wiedemann), and the South American fruit fly, Anastrepha fraterculus (Wiedemann) are pests of major economic importance in Argentina and worldwide. One way to control them is the use of insecticide in sprays or baits. The repeated use of a particular product exerts a strong selection pressure and can lead to development of resistance. The aim of this study was to determine baseline data of four insecticides with different mechanisms of action through laboratory bioassays. The products used were commercial formulations of cyantraniliprole, chlorpyrifos, lambdacyalothrin and spinosad. The mean lethal concentration was estimated by a dose-response curve analysis. Cyantraniliprole and chlorpyrifos were equally susceptible for males and females of both species. For lambdacyalothrin differences between the two species were detected; LC50 of A. fraterculus (0.058 and 0.074 for males and females respectively) was lower than that of C. capitata (0.523 and 0.624 for males and females respectively). For spinosad, A. fraterculus males were equally susceptible than males and females of C. capitata. These results generate reference values for Argentina and demonstrate the need to complete these studies with field evaluations of natural populations on which chemical control is exercised as well as with field and semi-field trials. It also shows the need to complete these studies in which the intake at different concentrations is measured.Fil: Paez Jerez, P. G.. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia. Cátedra. Terapéutica Vegetal; ArgentinaFil: Carrizo, B. N.. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Tucumán-Santiago del Estero. Estación Experimental Agropecuaria Famaillá; ArgentinaFil: Musse, R.. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia. Cátedra. Terapéutica Vegetal; ArgentinaFil: Varela, E.. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia. Cátedra. Terapéutica Vegetal; ArgentinaFil: Armiñana, A.. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia. Cátedra. Terapéutica Vegetal; ArgentinaFil: Milla, F.. Instituto Nacional de Tecnología Agropecuaria. Centro Nacional de Investigaciones Agropecuarias. Centro de Investigación de Ciencias Veterinarias y Agronómicas. Instituto de Genética; ArgentinaFil: Vera, Maria Teresa. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia. Cátedra. Terapéutica Vegetal; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: de la Vega, M. H.. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia. Cátedra. Terapéutica Vegetal; Argentin

    Non-Equilibrium Evolution of Scalar Fields in FRW Cosmologies I

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    We derive the effective equations for the out of equilibrium time evolution of the order parameter and the fluctuations of a scalar field theory in spatially flat FRW cosmologies.The calculation is performed both to one-loop and in a non-perturbative, self-consistent Hartree approximation.The method consists of evolving an initial functional thermal density matrix in time and is suitable for studying phase transitions out of equilibrium. The renormalization aspects are studied in detail and we find that the counterterms depend on the initial state. We investigate the high temperature expansion and show that it breaks down at long times. We also obtain the time evolution of the initial Boltzmann distribution functions, and argue that to one-loop order or in the Hartree approximation, the time evolved state is a ``squeezed'' state. We illustrate the departure from thermal equilibrium by numerically studying the case of a free massive scalar field in de Sitter and radiation dominated cosmologies. It is found that a suitably defined non-equilibrium entropy per mode increases linearly with comoving time in a de Sitter cosmology, whereas it is {\it not} a monotonically increasing function in the radiation dominated case.Comment: 29 pages, revtex 3.0, 11 figures available upon request, PITT-93-6; LPTHE-93-52; CMU-HEP-93-2

    Finite size effects near the onset of the oscillatory instability

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    A system of two complex Ginzburg - Landau equations is considered that applies at the onset of the oscillatory instability in spatial domains whose size is large (but finite) in one direction; the dependent variables are the slowly modulated complex amplitudes of two counterpropagating wavetrains. In order to obtain a well posed problem, four boundary conditions must be imposed at the boundaries. Two of them were already known, and the other two are first derived in this paper. In the generic case when the group velocity is of order unity, the resulting problem has terms that are not of the same order of magnitude. This fact allows us to consider two distinguished limits and to derive two associated (simpler) sub-models, that are briefly discussed. Our results predict quite a rich variety of complex dynamics that is due to both the modulational instability and finite size effects
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