The Galactic disk mass function: reconciliation of the HST and nearby determinations

We derive and parametrize the Galactic mass function (MF) below 1 \msol characteristic of both single objects and binary systems. We resolve the long standing discrepancy between the MFs derived from the HST and from the nearby luminosity functions, respectively. We show that this discrepancy stemmed from {\it two} cumulative effects, namely (i) incorrect color-magnitude determined distances, due a substantial fraction of M dwarfs in the HST sample belonging to the metal-depleted, thick-disk population, as corrected recently by Zheng et al. and (ii) unresolved binaries. We show that both the nearby and HST MF for unresolved systems are consistent with a fraction $\sim$50% of M-dwarf binaries, with the mass of both the primaries and the companions originating from the same underlying single MF. This implies that $\sim$30% of M dwarfs should have an M dwarf companion and $\sim$20% should have a brown dwarf companion, in agreement with recent determinations. The present calculations show that the so-called "brown-dwarf desert" should be reinterpreted as a lack of high mass-ratio (m_2/m_1\la 0.1) systems, and does not preclude a substantial fraction of brown dwarfs as companions of M dwarfs or for other brown dwarfs.Comment: 16 pages, Latex file, uses aasms4.sty, to appear in ApJ Letter

The impact of cultural dissonance and acculturation orientations on immigrant students' academic performance

Indexación: Scopus; Scielo; Redalyc.Prior research has documented meaningful differences between school performance of immigrant and native students. Multicultural education has been associated with academic failure of foreign students. e aim of this study was to examine the impact of a set of psychosocial variables on the perceived academic achievement of first generation immigrant adolescents from public secondary schools in Northern Spain. Results showed that 46% of the variability in foreign students’ perceived academic performance was explained by home-school cultural dissonance. We also explored the impact of acculturation orientation to separation, perception of discrimination from teachers, school adjustment, and psychological well-being in academic performance. Any multicultural education context should take into account psychosocial adjustment, given its influence on academic performance of all studentsSe han hallado diferencias significativas entre el rendimiento académico de los inmigrantes y el de los estudiantes nativos. Sin embargo, hay una escasa evidencia acerca de los aspectos psicosociales de este fenómeno. El objetivo de este estudio fue examinar el impacto de un conjunto de variables psicosociales: disonancia cultural y orientaciones de aculturación en el rendimiento académico percibido de adolescentes inmigrantes de primera generación de centros de Educación Secundaria en el Norte de España. Los resultados mostraron que alrededor del 46% de la variabilidad en el rendimiento era explicada por la disonancia cultural entre escuela y hogar. Cualquier contexto de educación multicultural ha de tomar en consideración el ajuste psicosocial, dada su influencia en el rendimiento académico de los estudiantes.http://www.redalyc.org/jatsRepo/647/64753989003/index.htm

The Galactic disk mass-budget : I. stellar mass-function and density

In this paper, we use the general theory worked out within the past few years for the structure and the evolution of low-mass stars to derive the stellar mass-function in the Galactic disk down to the vicinity of the hydrogen-burning limit, from the observed nearby luminosity functions. The accuracy of the mass-magnitude relationships derived from the afore-mentioned theory is examined by comparison with recent, accurate observational relationships in the M-dwarf domain. The mass function is shown to flatten out below \sim 1 \msol but to keep rising down to the bottom of the main sequence. Combining the present determination below 1 \msol and Scalo's (1986) mass function for larger masses, we show that the mass function is well described over the entire stellar mass range, from \sim 100 \msol to \sim 0.1 \msol, by three functional forms, namely a two-segment power-law, a log-normal form or an exponential form, all normalized to the Hipparcos sample at 0.8 \msol. Integration of this mass function yields a reasonably accurate census of the entire stellar population in the Galactic disk, and its volume and surface mass-density.Comment: 31 pages, Latex file, uses aasms4.sty, ApJ, 2001, 554, 127

NL mind-best: aweb server for ligands and proteins discovery; theoretic experimental study of proteins of giardia lamblia

Comunicaciones a congreso

May Measurement Month 2017: an analysis of blood pressure screening in Spain-Europe.

May Measurement Month 2017 is a global initiative aimed at raising awareness of high blood pressure (BP) and to act as a temporary solution to the lack of screening programs worldwide, in which Spain participated actively. The primary objective was to raise awareness and increase control of BP in Spain. An opportunistic cross-sectional survey of volunteers aged ≥18 was set up in May 2017. Following the design of the International Society of Hypertension, data were collected from the 17 autonomous communities in which Spain is divided, mainly in community pharmacies, primary care centres and some hypertension (HT) units, and cardiovascular departments in hospitals. No additional training of volunteers was necessary. A total of 3849 individuals were screened. After multiple imputation, our data showed that 1923 (50.0%) had HT. In those not receiving antihypertensive medication, 17.5% were hypertensives, in individuals receiving antihypertensive medication, 33.9% had uncontrolled BP. May Measurement Month 2017 was the largest BP screening campaign undertaken in Spain. In total, 17.5% of people with HT did not receive medication. One-third of hypertensive participants receiving treatment did not have their BP controlled. These results confirm that an opportunistic screening can identify a significant number of subjects with and untreated and inadequately treated BP

ME20-S as a Potential Biomarker for the Evaluation of Uveal Melanoma

PURPOSE: We previously identified the presence of the melanocyte-specific secreted (ME20-S) glycoprotein in secretomes of uveal melanoma (UM) cultures. The aim of this study was to test for the presence and levels of ME20-S in the serum of patients with choroidal nevi and UM and correlate these levels with individual clinical data. METHODS: Serum ME20-S levels were determined by ELISA in 111 patients distributed into four categories (53 choroidal nevi, 30 untreated UM, 11 10-year disease-free [DF] UM, 17 hepatic metastatic UM) and 32 age- and sex-matched controls. ME20-S levels were correlated with individual clinical data. RESULTS: The UM and the metastatic groups showed significantly higher levels of serum ME20-S than the other groups (P < 0.001). ME20-S levels in the DF patients did not differ from those in the control group. In addition, log-transformed serum ME20-S levels showed a positive correlation with the thickness of the lesion mass in UM patients (regression coefficient 0.0689, 95% confidence interval 0.0689-0.1123, R2 = 27.1%). CONCLUSIONS: Elevated ME20-S serum levels are associated with tumor size and advanced stages of UM while low levels are characteristic of DF patients. ME20-S might be a promising serum marker for UM and useful for monitoring metastatic disease

Abundance Gradients and the Formation of the Milky Way

In this paper we adopt a chemical evolution model, which is an improved version of the Chiappini, Matteucci and Gratton (1997) model, assuming two main accretion episodes for the formation of the Galaxy. The present model takes into account in more detail than previously the halo density distribution and explores the effects of a threshold density in the star formation process, during both the halo and disk phases. In the comparison between model predictions and available data, we have focused our attention on abundance gradients as well as gas, stellar and star formation rate distributions along the disk. We suggest that the mechanism for the formation of the halo leaves detectable imprints on the chemical properties of the outer regions of the disk, whereas the evolution of the halo and the inner disk are almost completely disentangled. This is due to the fact that the halo and disk densities are comparable at large Galactocentric distances and therefore the gas lost from the halo can substantially contribute to building up the outer disk. We also show that the existence of a threshold density for the star formation rate, both in the halo and disk phase, is necessary to reproduce the majority of observational data in the solar vicinity and in the whole disk. Moreover, we predict that the abundance gradients along the Galactic disk must have increased with time and that the average [alpha/Fe] ratio in stars (halo plus disk) slightly decrease going from 4 to 10 Kpcs from the Galactic center. We also show that the same ratios increase substantially towards the outermost disk regions and the expected scatter in the stellar ages decreases, because the outermost regions are dominated by halo stars.Comment: 41 pages (including the figures), To be published in Ap

Contamination level and spatial distribution of heavy metals in water and sediments of El Guájaro Reservoir, Colombia

Heavy metals have become a subject of special concern worldwide, mainly due to high persistence in the environment, toxicity, biogeochemical recycling and ecological risk. Therefore, the objective of this investigation was to analyze the spatial–temporal distribution of heavy metals in water and sediments to determine the environmental status of El Guájaro Reservoir, where such studies have not been developed. Two measurement campaigns (dry and wet period) were carried out and eight sampling stations were selected. A comparison of water and sediment quality parameters with existing national and international regulations was done. Also, heavy metal distribution maps were generated, and the geoaccumulation index was calculated to identify sources and sediments contamination level. Based on the obtained results, agriculture and mining activities are the main causes of the reservoir contamination. This metals levels could be a potential risk for the aquatic life and the populations that are supplied from this water body

Simulated effect of pneumococcal vaccination in the Netherlands on existing rules constructed in a non-vaccinated cohort predicting sequelae after bacterial meningitis

BACKGROUND: Previously two prediction rules identifying children at risk of hearing loss and academic or behavioral limitations after bacterial meningitis were developed. Streptococcus pneumoniae as causative pathogen was an important risk factor in both. Since 2006 Dutch children receive seven-valent conjugate vaccination against S. pneumoniae. The presumed effect of vaccination was simulated by excluding all children infected by S. pneumoniae with the serotypes included in the vaccine, from both previous collected cohorts (between 1990-1995). METHODS: Children infected by one of the vaccine serotypes were excluded from both original cohorts (hearing loss: 70 of 628 children; academic or behavioral limitations: 26 of 182 children). All identified risk factors were included in multivariate logistic regression models. The discriminative ability of both new models was calculated. RESULTS: The same risk factors as in the original models were significant. The discriminative ability of the original hearing loss model was 0.84 and of the new model 0.87. In the academic or behavioral limitations model it was 0.83 and 0.84 respectively. CONCLUSION: It can be assumed that the prediction rules will also be applicable on a vaccinated population. However, vaccination does not provide 100% coverage and evidence is available that serotype replacement will occur. The impact of vaccination on serotype replacement needs to be investigated, and the prediction rules must be validated externally