540 research outputs found

    ¿Cómo casi destruir un mercado sin querer y no fallar en el intento? El caso del impuesto sobre los automóviles de lujo en Argentina

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    Under the pressure of a growing capital outflow, by the end of 2013 the Argentine government implemented what was known as the tax on "luxury cars". Even when not explicitly declared, the main objective was to reduce imports of most expensive cars to reduce the trade deficit of the automotive sector, which was contributing heavily to the capital account deficit. Even when the policy could be categorized as "successful" in terms of reducing a USD 4.5 billion deficit in 2013 to one of just over USD 0.7 billion in 2014, it had a devastating and lasting impact on the internal market, that just in 2013 had achieved a record in sales. We obtain that during the first year of the implementation of the tax, the overall impact on sales of models reached by the tax was 53.7%. Despite some differences, the negative impact took place throughout the whole year. Not surprisingly, cars reached by the highest tax rate were most affected, as well as carmakers that produce more expensive varieties. However, even when the measure may have been designed to have a direct impact on a small part of the market, the negative effects extended to the whole market.Bajo la presión de una creciente salida de capitales, a fines del año 2013 el gobierno argentino implementó lo que se conoció como el impuesto a los "autos de lujo". Aunque no declarado explícitamente, el objetivo principal era reducir las importaciones de los automóviles más caros para reducir el déficit comercial del sector automotriz, que contribuía de manera importante al déficit de la cuenta de capital. Más allá del hecho de que la política podría calificarse de "exitosa" en cuanto a la reducción de un déficit de USD 4.500 millones en 2013 a uno de poco más de USD 700 millones en 2014, tuvo un impacto devastador y duradero en el mercado interno, que apenas un año antes, en 2013, había alcanzado un récord de ventas. Los resultados muestran que durante el primer año de la aplicación del impuesto, el impacto global en las ventas de los modelos alcanzados por el mismo fue del 53,7%. A pesar de algunas diferencias, el impacto negativo se produjo a lo largo todo el año 2014. No sorprende que los automóviles alcanzados por la tasa del 50% fueran los más afectados, así como los fabricantes de modelos más caros. Sin embargo, incluso cuando la medida puede haber sido diseñada para tener un impacto directo en una pequeña parte del mercado, los efectos negativos se extendieron a la totalidad del mismo.

    Habitat use by armadillos in agroecosystems of central Argentina: does plot identity matter?

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    In agroecosystems, the use of cultivated plots by mammals depends on habitat structure as well as on the degree of species specialization. In the Pampas of Argentina, during the last 2-3 decades, there has been a continuing expansion of cropland. The aim of this study was to analyze how the identity and characteristics of agricultural plots may have affected the activity of 2 species of armadillos (Chaetophractus villosus and Dasypus hybridus) in a rural landscape. We carried out 4 sampling sessions between December 2011 and June 2013, surveying 175 plots during spring-summer and 194 during fall at 25 different sites in the Pampas of Buenos Aires province, Argentina. In each plot, we surveyed for signs (burrows and holes) along a 600×6 m transect in order to assess armadillo activity and measured 4 habitat structural variables. As expected, there were structural differences between types of agricultural plots. Across all plots, a total of 6,654 armadillo signs were found (C. villosus = 5,009, D. hybridus = 1,645). Generalized linear mixed models revealed that during both seasons, the type of plot explained much of the variation in armadillo activity, except during spring-summer for D. hybridus. C. villosus had higher use of plots with a longer history of non-tillage (e.g., soybean), while there was more evidence of D. hybridus activity in plots with less human intervention (e.g., grasslands), especially during fall. Overall, D. hybridus and C. villosus were more sensitive to the particular structural features of plots rather than to the kind of land use practiced (crop field or rangeland). These results have important implications for future management decisions in the Pampas region because during the last decades, farming of soybeans has expanded at the expense of grasslands, and this change appears to have differentially affected these 2 species of armadillos.Centro de Estudios Parasitológicos y de VectoresFacultad de Ciencias Naturales y Muse

    Mathematical assessment of the role of vector insecticide resistance and feeding/resting behavior on malaria transmission dynamics: Optimal control analysis

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    This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.The large-scale use of insecticide-treated bednets (ITNs) and indoor residual spraying (IRS), over the last two decades, has resulted in a dramatic reduction of malaria incidence globally. However, the effectiveness of these interventions is now being threatened by numerous factors, such as resistance to insecticide in the mosquito vector and their preference to feed and rest outdoors or early in the evening (when humans are not protected by the bednets). This study presents a new deterministic model for assessing the population-level impact of mosquito insecticide resistance on malaria transmission dynamics. A notable feature of the model is that it stratifies the mosquito population in terms of type (wild or resistant to insecticides) and feeding preference (indoor or outdoor). The model is rigorously analysed to gain insight into the existence and asymptotic stability properties of the various disease-free equilibria of the model namely the trivial disease-free equilibrium, the non-trivial resistant-only boundary disease-free equilibrium and a non-trivial disease-free equlibrium where both the wild and resistant mosquito geneotypes co-exist). Simulations of the model, using data relevant to malaria transmission dynamics in Ethiopia (a malaria-endemic nation), show that the use of optimal ITNs alone, or in combination with optimal IRS, is more effective than the singular implementation of an optimal IRS-only strategy. Further, when the effect of the fitness cost of insecticide resistance with respect to fecundity (i.e., assuming a decrease in the baseline birth rate of new resistant-type adult female mosquitoes) is accounted for, numerical simulations of the model show that the combined optimal ITNs-IRS strategy could lead to the effective control of the disease, and insecticide resistance effectively managed during the first 8 years of the 15-year implementation period of the insecticides-based anti-malaria control measures in the community.National Institute for Mathematical and Biological SynthesisNSF Award # EF-0832858The University of Tennessee, Knoxvill

    Contribution a l’étude physicochimique de l’écosystème lacustre Dayet Aoua au Maroc

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    L’étude consiste à la détermination de la qualité physicochimique des eaux du lac Dayet Aoua situé dans le Moyen Atlas au Maroc juste après son dernier desséchement survenu en été 2002. Les résultats d’analyse obtenus au cours de la période d’étude comprise entre février et juillet 2005, montrent que les eaux du lac sont bicarbonatées calciques et magnésiennes, dures à très dures. La dureté dépend essentiellement des ions magnésium. Les analyses des formes azotées et des orthophosphates des eaux du lac donnent des valeurs très faibles, et ne décèlent aucune sorte de pollution de type organique pouvant engendrer son eutrophisation, ce qui permet de le classeractuellement parmi les lacs oligotrophes.Mots-clés : lac, physico-chimie, pollution organique, oligotrophe

    Determining Temperature trends in the Granary Areas of Peninsular Malaysia using Mann-Kendall and Sen’s Slope Estimator

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    The spatiotemporal dynamics of temperature as well as rainfall have received greater attention from the scientific communities This study analysed temperature variability in the three granary areas of Peninsular Malaysia using descriptive statistics parametric least square regression and nonparametric Mann- Kendall and Sen s slope estimator The study identified significant warming trend in the annual mean maximum temperature in two of the study areas i e Subang Jaya and Kota Bharu Also significant warming trend was detected in the annual minimum temperature and significant increasing trend in some of the monthly maximum and minimum temperatures for all the three stations Also the result reveals spatial and temporal variation in both the maximum and minimum temperature at annual monthly and seasonal scales For the annual scale maximum temperature this study identified a warming trend for the two stations with about 0 014oC per year 1 4oC per 100 year

    Early Biometric Lag in the Prediction of Small for Gestational Age Neonates and Preeclampsia

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    OBJECTIVE: An early fetal growth lag may be a marker of future complications. We sought to determine the utility of early biometric variables in predicting adverse pregnancy outcomes. METHODS: In this retrospective cohort study, the crown-rump length at 11 to 14 weeks and the head circumference, biparietal diameter, abdominal circumference, femur length, humerus length, transverse cerebellar diameter, and estimated fetal weight at 18 to 24 weeks were converted to an estimated gestational age using published regression formulas. Sonographic fetal growth (difference between each biometric gestational age and the crown-rump length gestational age) minus expected fetal growth (number of days elapsed between the two scans) yielded the biometric growth lag. These lags were tested as predictors of small for gestational age (SGA) neonates (≤10th percentile) and preeclampsia. RESULTS: A total of 245 patients were included. Thirty-two (13.1%) delivered an SGA neonate, and 43 (17.6%) had the composite outcome. The head circumference, biparietal diameter, abdominal circumference, and estimated fetal weight lags were identified as significant predictors of SGA neonates after adjusted analyses (P \u3c .05). The addition of either the estimated fetal weight or abdominal circumference lag to maternal characteristics alone significantly improved the performance of the predictive model, achieving areas under the curve of 0.72 and 0.74, respectively. No significant association was found between the biometric lag variables and the development of preeclampsia. CONCLUSIONS: Routinely available biometric data can be used to improve the prediction of adverse outcomes such as SGA. These biometric lags should be considered in efforts to develop screening algorithms for adverse outcomes

    Designing and implementing a communications strategy: lessons learnt from HIV and Sexual and Reproductive Health Research Programme Consortia.

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    In recent years there has been increasing recognition of the importance of strategic research communication. Health research organisations need to be able to communicate their research effectively to increase the probability that the findings influence policy and practice, and benefit those in greatest need. Many research funders are making communications a requirement of research funding. This paper reflects on the experience in developing and implementing communications strategies of several Research Programme Consortia funded by the Department for International Development.Different research topics will require different communications approaches in order to be effective. This is reflected in the diversity of strategies employed by different research programmes. Strategic research communications designed to influence policy and practice require different skills and expertise from those required for carrying out research and writing it up for publication in academic journals. Therefore researchers involved in communicating research should be supported in this work. One of the ways in which research programme consortia have sought to do this is through convening workshops to develop the communications skills of researchers from partner organisations. These have proven invaluable. Another way of providing ongoing support to those involved in communicating research is through a Communications Community of Practice. Where this has been used it has proven a good way to support researchers both with ideas and resources, but also a strong sense of belonging to a community that shares a common concern with communication. Developing strong partnerships with research users, other research organisations, knowledge intermediaries and other stakeholders is vital for effective communication.Embracing the challenges and opportunities presented by communicating research to influence policy practice is vital if research is to have maximum possible impact, and demonstrate its worth at a time when funding for health and development activities is at risk. Sharing lessons learnt in this process between research programmes is important to support this work

    Will vaccine-derived protective immunity curtail COVID-19 variants in the US?

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    Multiple effective vaccines are currently being deployed to combat the COVID-19 pandemic, and are viewed as the major factor in marked reductions of disease burden in regions with moderate to high vaccination coverage. The effectiveness of COVID-19 vaccination programs is, however, significantly threatened by the emergence of new SARS-COV-2 variants that, in addition to being more transmissible than the wild-type (original) strain, may at least partially evade existing vaccines. A two-strain (one wildtype, one variant) and two-group (vaccinated or otherwise) mechanistic mathematical model is designed and used to assess the impact of the vaccine-induced cross-protective efficacy on the spread the COVID-19 pandemic in the United States. Rigorous analysis of the model shows that, in the absence of any co-circulating SARS-CoV-2 variant, the vaccine-derived herd immunity threshold needed to eliminate the wild-type strain can be achieved if 59% of the US population is fully-vaccinated with either the Pfizer or Moderna vaccine. This threshold increases to 76% if the wild-type strain is co-circulating with the Alpha variant (a SARS-CoV-2 variant that is 56% more transmissible than the wild-type strain). If the wild-type strain is co-circulating with the Delta variant (which is estimated to be 100% more transmissible than the wild-type strain), up to 82% of the US population needs to be vaccinated with either of the aforementioned vaccines to achieve the vaccine-derived herd immunity. Global sensitivity analysis of the model reveal the following four parameters as the most influential in driving the value of the reproduction number of the variant strain (hence, COVID-19 dynamics) in the US: (a) the infectiousness of the co-circulating SARS-CoV-2 variant, (b) the proportion of individuals fully vaccinated (using Pfizer or Moderna vaccine) against the wild-type strain, (c) the cross-protective efficacy the vaccines offer against the variant strain and (d) the modification parameter accounting for the reduced infectiousness of fully-vaccinated individuals experiencing breakthrough infection. Specifically, numerical simulations of the model show that future waves or surges of the COVID-19 pandemic can be prevented in the US if the two vaccines offer moderate level of cross-protection against the variant (at least 67%). This study further suggests that a new SARS-CoV-2 variant can cause a significant disease surge in the US if (i) the vaccine coverage against the wild-type strain is low (roughly <66%) (ii) the variant is much more transmissible (e.g., 100% more transmissible), than the wild-type strain, or (iii) the level of cross-protection offered by the vaccine is relatively low (e.g., less than 50%). A new SARS-CoV-2 variant will not cause such surge in the US if it is only moderately more transmissible (e.g., the Alpha variant, which is 56% more transmissible) than the wild-type strain, at least 66% of the population of the US is fully vaccinated, and the three vaccines being deployed in the US (Pfizer, Moderna, and Johnson & Johnson) offer a moderate level of cross-protection against the variant.The Simons Foundation and the National Science Foundation.http://www.keaipublishing.com/idmam2022Mathematics and Applied Mathematic
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