173 research outputs found

    Responses of a native and a recent invader snail to warming and dry conditions: the case of the lower Ebro River

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    Aquatic habitats have been highly modified by human actions that reduce their native diversity and create conditions suitable for tolerant alien species. Pomacea maculata was detected in 2009 in both the alluvial plain and the final stretch of the Ebro River. Since then, a permanent population has stabilized in the littoral area of the river where the water level fluctuates according to the river discharge. Melanopsis tricarinata is an endemic snail species highly affected by the reduction in its natural habitat. Currently, the two species do not share the same reaches in the river, but the possibility exists, as the distribution of the P. maculata is constantly increasing. This study aims to analyse the diets and to assess the responses of both snails to global change. The diet of both species was analysed in the field and their responses to water warming and dryness compared under laboratory conditions. This study includes the calculation of future river water temperatures based on air temperature projections. In addition, based on water discharge management scenarios, the study estimated the increase in dry river bed area. The diet of both snail species was similar and based on Cladophora. P. maculata better resisted high temperatures and dry conditions than M. tricarinata. The projections of water temperatures showed an increase in daily temperatures, especially in summer. The hydraulic model suggested that a relevant increase in dry river bed areas will occur. Overall, these results provide insight into the global change factors that could favour P. maculata spread in the river and the reduction in suitable habitat for M. tricarinata and will be useful for future decisions of water discharge management

    Solution of inverse problem - regularization via thermodynamical criterion

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    In engineering practice, measuring temperature on both sides of a wall (of, for example, turbine casing or combustion chamber) is not always possible. On the other hand, measurement of both temperature and heat flux on the outer surface of the wall is possible. For transient heat conduction equation, measurements of temperature and heat flux supplemented by the initial condition state the Cauchy problem, which is ill-conditioned In this paper, the stable solution is obtained for the Cauchy problem using the Laplace transformation and the minimisation of continuity in the process of integration of convolution. Test examples confirm proposed algorithm for the inverse problem solution.Papers presented to the 12th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Costa de Sol, Spain on 11-13 July 2016

    Joint modeling of interval counts of recurrent events and death

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    When a recurrent event process is ended by death, this may imply dependent censoring if the two processes are associated. Such dependent censoring would have to be modeled to obtain a valid inference. Moreover, the dependence between the recurrence process and the terminal event may be the primary topic of interest. Joint frailty models for recurrent events and death, which include a separate dependence parameter, have been proposed for exactly observed recurrence times. However, in many situations, only the number of events experienced during consecutive time intervals are available. We propose a method for estimating a joint frailty model based on such interval counts and observed or independently censored terminal events. The baseline rates of the two processes are modeled by piecewise constant functions, and Gaussian quadrature is used to approximate the marginal likelihood. Covariates can be included in a proportional rates setting. The observation intervals for the recurrent event counts can differ between individuals. Furthermore, we adapt a score test for the association between recurrent events and death to the setting in which only individual interval counts are observed. We study the performance of both approaches via simulation studies, and exemplify the methodology in a biodemographic study of the dependence between budding rates and mortality in the species Eleutheria dichotoma.Development and application of statistical models for medical scientific researc

    Experiencias y comprensiones sobre violencias contra mujeres jóvenes : relatos de mujeres entre 18 y 29 años en la ciudad de Bogotá

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    La violencia contra mujeres jóvenes es una problemática social que ha incrementado en los últimos años, ya que las mujeres entre los 18 y 29 años son las víctimas más frecuentes de violencia basada en género. Para el año 2013, en Colombia el más alto número de mujeres asesinadas se encontraban entre los 15 y 29 años. Sin embargo, es notable el bajo índice de denuncia de hechos de violencia contra mujeres en esta etapa del ciclo vital. Por tanto, esta investigación indaga sobre experiencias y comprensiones relativas a las violencias contra las mujeres relatadas por mujeres jóvenes entre 18 y 29 años en la ciudad de Bogotá. Para el análisis de los relatos se acude a la perspectiva de género y a categorías como subjetividad femenina, violencia contra mujeres y ámbito público-privado. Se utiliza una metodología con enfoque cualitativo y se diseña un cuestionario con 24 preguntas que fue aplicado a 40 mujeres de todos los estratos socioeconómicos, divididas en dos rangos de edades: entre 18 y 23 años, y entre 24 y 29 años, posteriormente, se realizó un grupo focal con seis mujeres. Se identifica que los tipos de violencia psicológica, sexual y física son las que más afectan a las mujeres jóvenes. Igualmente se hace evidente que, si bien las jóvenes reconocen y son conscientes sobre situaciones y tipos de violencias en lugares públicos y privados en los que se sienten o están efectivamente en riesgo, la persistencia de roles estereotipados de género coexisten con discursos contradictorios de contenido relativamente emancipatorio respecto a condiciones históricas y culturales que configuran sus subjetividades, lo cual incide de manera negativa respecto a prácticas de autoprotección y de denuncia.Violence against young women is a social issue that has increased in the last few years, women between the ages of 18 and 29 are the most frequent victims of gender-based violence. In 2013, the highest number of murdered women in Colombia was between the ages of 15 and 29. However the report rate of these violent crimes against women at this stage of their life cycle is notably low. Therefore, this investigation is about experiences related to violence against women, described by young women between the ages of 18 and 29 in the city of Bogota. For the analysis of the stories, we resort to gender perspective and categories like feminine subjectivity, violence against women, and the public-private sector. We opted for a method with a qualitative focus and designed a questionnaire with 24 questions that was presented to 40 women of all the socioeconomic levels, divided in two age groups: between 18 and 23, and between 24 and 29, afterwards we formed a focal group of six women. We identified that the types of violence that most affects young women are psychological, sexual, and physical. Likewise, it s evident that if young women recognize and are conscious about situations and types of violence in public and private places in which they feel or are in fact at risk, the persistence of stereotypical gender roles coexist with contradictory speeches of relatively emancipatory content regarding historical and cultural conditions that configure their subjectivity, which influences them in a negative way regarding practices of autoprotection and reporting of crimes.Psicólogo (a)Pregrad

    Structural insights into regulation of nuclear receptors by ligands

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    Nuclear receptors are DNA-binding transcription factors, the transcriptional function of many of which depends on the binding of ligands, a feature that distinguishes nuclear receptors from other transcription factors. This review will summarize recent advances in our knowledge of the interaction between selected nuclear receptors and their cognate ligands

    A multilab study of bilingual infants: Exploring the preference for infant-directed speech

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    From the earliest months of life, infants prefer listening to and learn better from infant-directed speech (IDS) than adult-directed speech (ADS). Yet, IDS differs within communities, across languages, and across cultures, both in form and in prevalence. This large-scale, multi-site study used the diversity of bilingual infant experiences to explore the impact of different types of linguistic experience on infants’ IDS preference. As part of the multi-lab ManyBabies project, we compared lab-matched samples of 333 bilingual and 385 monolingual infants’ preference for North-American English IDS (cf. ManyBabies Consortium, in press (MB1)), tested in 17 labs in 7 countries. Those infants were tested in two age groups: 6–9 months (the younger sample) and 12–15 months (the older sample). We found that bilingual and monolingual infants both preferred IDS to ADS, and did not differ in terms of the overall magnitude of this preference. However, amongst bilingual infants who were acquiring North-American English (NAE) as a native language, greater exposure to NAE was associated with a stronger IDS preference, extending the previous finding from MB1 that monolinguals learning NAE as a native language showed a stronger preference than infants unexposed to NAE. Together, our findings indicate that IDS preference likely makes a similar contribution to monolingual and bilingual development, and that infants are exquisitely sensitive to the nature and frequency of different types of language input in their early environments

    Revisiting mortality deceleration patterns in a gamma-Gompertz-Makeham framework

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    We calculate life-table aging rates (LARs) for overall mortality by estimating a gamma-Gompertz-Makeham (G GM) model and taking advantage of LAR’s parametric representation by Vaupel and Zhang [34]. For selected HMD countries, we study how the evolution of estimated LAR patterns could explain observed 1) longevity dynamics, and 2) mortality improvement or deterioration at different ages. Surprisingly, the age of mortality deceleration x showed almost no correlation with a number of longevity measures apart from e0. In addition, as mortality concentrates at older ages with time, its characteristic bell-shaped pattern becomes more pronounced. Moreover, in a GGM framework, we identify the impact of senescent mortality on shape of the rate of population aging. We also find evidence for a strong relationship between x and the statistically significant curvilinear changes in the evolution of e0 over time. Finally, model-based LARs appear to be consistent with point b) of the “heterogeneity hypothesis” [12]: mortality deceleration, due to selection effects, should shift to older ages as the level of total adult mortality declines

    Low-Resolution Molecular Models Reveal the Oligomeric State of the PPAR and the Conformational Organization of Its Domains in Solution

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    The peroxisome proliferator-activated receptors (PPARs) regulate genes involved in lipid and carbohydrate metabolism, and are targets of drugs approved for human use. Whereas the crystallographic structure of the complex of full length PPARγ and RXRα is known, structural alterations induced by heterodimer formation and DNA contacts are not well understood. Herein, we report a small-angle X-ray scattering analysis of the oligomeric state of hPPARγ alone and in the presence of retinoid X receptor (RXR). The results reveal that, in contrast with other studied nuclear receptors, which predominantly form dimers in solution, hPPARγ remains in the monomeric form by itself but forms heterodimers with hRXRα. The low-resolution models of hPPARγ/RXRα complexes predict significant changes in opening angle between heterodimerization partners (LBD) and extended and asymmetric shape of the dimer (LBD-DBD) as compared with X-ray structure of the full-length receptor bound to DNA. These differences between our SAXS models and the high-resolution crystallographic structure might suggest that there are different conformations of functional heterodimer complex in solution. Accordingly, hydrogen/deuterium exchange experiments reveal that the heterodimer binding to DNA promotes more compact and less solvent-accessible conformation of the receptor complex
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