Cosmology with a Continuous Tower of Scalar Fields

We study the cosmological evolution for a universe in the presence of a continuous tower of massive scalar fields which can drive the current phase of accelerated expansion of the universe and, in addition, can contribute as a dark matter component. The tower consists of a continuous set of massive scalar fields with a gaussian mass distribution. We show that, in a certain region of the parameter space, the {\it heavy} modes of the tower (those with masses much larger than the Hubble expansion rate) dominate at early times and make the tower behave like the usual single scalar field whose coherent oscillations around the minimum of the potential give a matter-like contribution. On the other hand, at late times, the {\it light} modes (those with masses much smaller than the Hubble expansion rate) overcome the energy density of the tower and they behave like a perfect fluid with equation of state ranging from 0 to -1, depending on the spectral index of the initial spectrum. This is a distinctive feature of the tower with respect to the case of quintessence fields, since a massive scalar field can only give acceleration with equation of state close to -1. Such unique property is the result of a synergy effect between the different mass modes. Interestingly, we find that, for some choices of the spectral index, the tower tracks the matter component at high redshifts (or it can even play the role of the dark matter) and eventually becomes the dominant component of the universe and give rise to an accelerated expansion.Comment: 13 pages, 8 figures. V2: minor changes to match published versio

Quantiles for Fractions and Other Mixed Data

This paper studies the estimation of quantile regression for fractional data, focusing on the case where there are mass-points at zero or/and one. More generally, we propose a simple strategy for the estimation of the conditional quantiles of data from mixed distributions, which combines standard results on the estimation of censored and Box-Cox quantile regressions. The implementation of the proposed method is illustrated using a well-known dataset.

Quantiles for Fractions and Other Mixed Data

This paper studies the estimation of quantile regression for fractional data, focusing on the case where there are mass-points at zero or/and one. More generally, we propose a simple strategy for the estimation of the conditional quantiles of data from mixed distributions, which combines standard results on the estimation of censored and Box-Cox quantile regressions. The implementation of the proposed method is illustrated using a well-known dataset

A model of maxilla resection to test new hybrid implants:macroporous titanium and tissue engineering elements

Maxillary bone loss in commonly found in humans, due to bone ageing, tooth loos, periodontal disease and, more severely, to trauma, radiotherapy and tumor resection. Masillofacial reconstructive surgery is a still unmet clinical demand, available therapies include grafting of autologous or heterologous bone tissue and/or the implantation of metallic plates, buy these treatments are still unable to resume form and function. The emrgence of 3D-printing technology applied to metal alloys now allows the manufacturing of customized, patient-tailored prosthetic implants. However, poor bone quiality at the implant site due to ageing or disease still hamper proper osseointegration. By combining Electron Beam Melting metal sintering and tissue engineering, we are developing hybrid maxillofacial implants, wher a metal framework of Ti6Al4V alloy confers both and appropiaate shape and mechanical stabilty, while stem cells and osteogenic molecules stimulate bone growth into the metal framework, thus pormoting osseointegration. We hereby present the in vitro work driving to the development of our hybrid maxillofacial prostheses, as well as the setting up of an in vivo model of complete maxilla full resection, created in order to test the prostheses in a preclinical studyUniversidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Matrix metalloproteinases: Targets for doxycycline to prevent the vascular alterations of hypertension

AbstractHypertension is associated with well known structural and functional alterations in both resistance and conduit arteries, which may be the result from long-lasting high blood pressure and may also be the cause of maintained hypertension and its complications. Therefore, in addition to lowering blood pressure, therapeutic strategies targeting the structural and functional modifications found in hypertensive patients may prevent the cardiovascular events and decrease the death rates associated with hypertension. Mounting evidence indicates that many vascular alterations associated with sustained hypertension are due to imbalanced matrix metalloproteinases (MMPs), a family of zinc-endopeptidases that degrade not only proteins of extracellular matrix (ECM) but several other substrates. Recent observations showed that abnormal MMP activity is a feature of the pathogenesis of hypertension and other diseases, thus justifying the development of drugs aiming at MMP downregulation. This review focuses on the extracellular actions of MMPs in hypertension-induced chronic vascular alterations. We then discuss the effects of MMP inhibitors, especially doxycycline, on the vascular changes associated with hypertension. There is now strong evidence that MMP inhibition with doxycycline (and maybe other MMP inhibitors) may attenuate the functional and structural alterations associated with hypertension, including increases in arterial stiffness. These beneficial effects may be, at least in part, independent of their antihypertensive effects

Quantiles for counts

This paper studies the estimation of conditional quantiles of counts. Given the discreteness of the data, some smoothness has to be artificially imposed on the problem. The methods currently available to estimate quantiles of count data either assume that the counts result from the discretization of a continuous process, or are based on a smoothed objective function. However, these methods have several drawbacks. We show that it is possible to smooth the data in a way that allows inference to be performed using standard quantile regression techniques. The performance and implementation of the estimator are illustrated by simulations and an application.

Predictors of high-quality cord blood units

BACKGROUNDAnalysis of umbilical cord blood (UCB) transplants shows a correlation between engraftment and total number of infused cells. Thus, it is worth evaluating what maternal and neonatal characteristics and collection techniques may affect the quality of UCB units. STUDY DESIGN AND METHODSA cross-sectional study was performed with 7897 donors sequentially selected in three health care institutions in Brazil from October 2004 to March 2012, in which both quantitative and qualitative approaches were applied. All donors were considered suitable for cord blood collection. RESULTSThe maternal and neonatal characteristics and techniques of collection that influenced the total number of nucleated cells (TNCsp<0.001) were type of delivery, newborn weight and sex, and institution of UCB collection. The TNC count was associated with gestational age (p=0.008), type of delivery (p<0.001), newborn sex (p<0.001), newborn weight (p<0.001), and UCB collection technique (p=0.003). Center B presented the largest number of nucleated cells in its results (p<0.001), followed by Center A (p=0.001). Other characteristics, such as maternal age, were analyzed but were not relevant for the nucleated cell number. CONCLUSIONThis study provides elements for a model that allows an efficient selection of UCB donors, prioritizing candidates who have a better chance to lead to an optimized use of cord blood cells units.Univ Fed Sao Paulo UNIFESP, Escola Paulista Enfermagem, Sao Paulo, BrazilInst Nacl Cardiol, Rio De Janeiro, BrazilInst Israelita Ensino & Pesquisa Albert Einstein, Sao Paulo, BrazilHosp Israelita Albert Einstein, Dept Hemoterapia, Sao Paulo, BrazilUniv Fed Sao Paulo UNIFESP, Escola Paulista Enfermagem, Sao Paulo, BrazilWeb of Scienc

The participation of Wajapi women from the State of Amapa (Brazil) in the traditional use of medicinal plants - a case study

Background: the purpose of this study was to analyze the importance of traditional medicinal plants use to Wajapi women in the State of Amapa, Brazil, as well as their practices in the local common illnesses of treatment considering the prevailing practice by non-Indians.Methods: This study was conducted in the Community of the Wajapi Indigenous People, a Brazilian territory located in the central western State of Amapa. Wajapi women were selected for the interview since they have the responsibility to harvest, collect and prepare the preparations. the studied women were residents of four villages. the number of women within these four villages is 24.Results and conclusions: the findings fell into the following three categories: 1) the daily use of medicinal plants by women and main methods of application. in this category, the botanical families found included Leguminosae-Caesalpinoideae, Anacardiaceae, Meliaceae, and Rubiaceae. the main forms of use found were teas, baths, maceration, in natura, and juices; 2) Through analysis of illness and treatment records, a lack of knowledge integration in the health system was shown to be due to a variety of gaps and the need of health professionals to be more aware about the local culture which they intend to work with, what could decrease the prevailing barriers between the social groups involved; 3) Traditional knowledge and possible sustainability can be fostered by stimulating the transmission of traditional knowledge from generation to generation, therefore reducing the dependence on industrialized medicines and also by maintaining an appreciation of those practices among youngsters, who tend to question them.Univ Fed Amapa, Curso Enfermagem, Ctr Ciencias Biol & Saude, BR-68902280 Macapa, Amapa, BrazilUniv Fed Amapa, Lab Estudos Sociais, BR-68902280 Macapa, Amapa, BrazilUniversidade Federal de São Paulo Unifesp, DCET, Setor Ciencias Farmaceut, BR-09972270 Diadema, SP, BrazilUniv Fed Amapa, Lab Pesquisa Farm, Ctr Ciencias Biol & Saude, BR-68902280 Macapa, Amapa, BrazilUniversidade Federal de São Paulo Unifesp, DCET, Setor Ciencias Farmaceut, BR-09972270 Diadema, SP, BrazilWeb of Scienc

Performance and emission of pollutants of an agricultural engine with two-power take-off settings

Farming operations are usually performed implements driven by a power take-off (PTO) from tractors. Some manufacturers offer PTO settings named as economic (540E). Such configuration drives implements at lower tractor’s engine rotation, thus providing lower fuel consumption. An engine performance using standard (540) or 540E settings are different and poorly studied. The amounts of pollutants emitted by engines vary mainly with the applied load and rotation. The aim of this study was to compare the performance and exhaust emissions of a farming tractor engine under different PTO loads, using both standard (540) and 540E settings. Specific fuel consumption using 540E was an average 14.7% less than the standard setting. However, 540E promoted increasing levels of gas opacity, CO, CO2, NOx, and HC for the highest PTO power demands.Postprint (published version

Espectros integrados EFOSC2/NTT de 10 cúmulos estelares pertenecientes a las Nubes de Magallanes

We present integrated spectra in the optical range for 10 concentrated Magellanic Clouds’ (MCs) stellar clusters, six of them belonging to the Large Magellanic Cloud, and the other four to the Small Magellanic Cloud. The spectra were obtained with the EFOSC2 spectrograph (NTT-ESO, La Silla, Chile). We estimate simultaneously age and foreground reddening by comparing the continuum distribution and line strengths of the cluster spectra with those of template spectra. The present cluster sample complements previous ones, in an effort to create a spectral library for the MCs with several clusters per age bin.Se presentan espectros integrados en el rango optico obtenidos con el espectrografo EFOSC2 (NTT-ESO, La Silla, Chile) de 6 cumulos estelares (CEs) de la Nube Mayor de Magallanes (NMM) y 4 de la Nube Menor (NmM). Las edades y enrojecimientos se determinaron comparando la distribucion del continuo y la intensidad de lıneas espectrales con estas mismas caracterısticas en espectros patrones (templates). Los 10 cumulos estudiados abarcan un amplio rango de edad y estan levemente enrojecidos. Estos espectros seran de gran utilidad para actualizar las bases de templates actualmente existentes para la metalicidad tıpicamente subsolar de las Nubes de Magallanes (NMs).Fil: Ahumada, Andrea Veronica. Universidad Nacional de Cordoba. Observatorio Astronomico de Cordoba; ArgentinaFil: Benítez Llambay, Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomia Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomia Teórica y Experimental; ArgentinaFil: Santos, J. F. C.. Universidade Federal do Minas Gerais; BrasilFil: Claria Olmedo, Juan Jose. Universidad Nacional de Cordoba. Observatorio Astronomico de Cordoba; ArgentinaFil: Bica, E.. Universidade Federal do Rio Grande do Sul; BrasilFil: Piatti, Andres Eduardo. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentin