On the Number Density of Sunyaev-Zel'dovich Clusters of Galaxies

If the mean properties of clusters of galaxies are well described by the entropy-driven model, the distortion induced by the cluster population on the blackbody spectrum of the Cosmic Microwave Background radiation is proportional to the total amount of intracluster gas while temperature anisotropies are dominated by the contribution of clusters of about 10^{14} solar masses. This result depends marginally on cluster parameters and it can be used to estimate the number density of clusters with enough hot gas to produce a detectable Sunyaev-Zel'dovich effect. Comparing different cosmological models, the relation depends mainly on the density parameter Omega_m. If the number density of clusters could be estimated by a different method, then this dependence could be used to constrain Omega_m.Comment: 8 pages, 3 figures, submitted to ApJ Letter

Efficient plot-based floristic assessment of tropical forests

The tropical flora remains chronically understudied and the lack of floristic understanding hampers ecological research and its application for large-scale conservation planning. Given scarce resources and the scale of the challenge there is a need to maximize the efficiency of both sampling strategies and sampling units, yet there is little information on the relative efficiency of different approaches to floristic assessment in tropical forests. This paper is the first attempt to address this gap. We repeatedly sampled forests in two regions of Amazonia using the two most widely used plot-based protocols of floristic sampling, and compared their performance in terms of the quantity of floristic knowledge and ecological insight gained scaled to the field effort required. Specifically, the methods are assessed first in terms of the number of person-days required to complete each sample (‘effort’), secondly by the total gain in the quantity of floristic information that each unit of effort provides (‘crude inventory efficiency’), and thirdly in terms of the floristic information gained as a proportion of the target species pool (‘proportional inventory efficiency’). Finally, we compare the methods in terms of their efficiency in identifying different ecological patterns within the data (‘ecological efficiency’) while controlling for effort. There are large and consistent differences in the performance of the two methods. The disparity is maintained even after accounting for regional and site-level variation in forest species richness, tree density and the number of field assistants. We interpret our results in the context of selecting the appropriate method for particular research purposes

Malaria at Johannesburg Hospital A retrospective study

A total of 43 patients diagnosed as having malaria were admitled to Johannesburg Hospital during 1988; 40 (94%) were infected with Plasmodium falciparum. Only 26 patients (60%) were recorded as having used prophylaxis of any kind; chloroquine alone and in combination was used as prophylaxis by 17:. Patients were treated with quinine (alone or in combination) in 67% of cases. In 42% of patients chloroquine- resistant malaria was considered a possibility

Impact of Scale Dependent Bias and Nonlinear Structure Growth on the ISW Effect: Angular Power Spectra

We investigate the impact of nonlinear evolution of the gravitational potentials in the LCDM model on the Integrated Sachs-Wolfe (ISW) contribution to the CMB temperature power spectrum, and on the cross-power spectrum of the CMB and a set of biased tracers of the mass. We use an ensemble of N-body simulations to directly follow the potentials and compare results to perturbation theory (PT). The predictions from PT match the results to high precision for k<0.2 h/Mpc. We compute the nonlinear corrections to the angular power spectrum and find them to be <10% of linear theory for l<100. These corrections are swamped by cosmic variance. On scales l>100 the departures are more significant, however the CMB signal is more than a factor 10^3 larger at this scale. Nonlinear ISW effects therefore play no role in shaping the CMB power spectrum for l<1500. We analyze the CMB--density tracer cross-spectrum using simulations and renormalized bias PT, and find good agreement. The usual assumption is that nonlinear evolution enhances the growth of structure and counteracts linear ISW on small scales, leading to a change in sign of the CMB-LSS cross-spectrum at small scales. However, PT analysis suggests that this trend reverses at late times when the logarithmic growth rate f(a)=dlnD/dlna<0.5 or om_m(a)<0.3. Numerical results confirm these expectations and we find no sign change in ISW-LSS cross-power for low redshifts. Corrections due to nonlinearity and scale dependence of the bias are found to be <10% for l<100, therefore below the S/N of the current and future measurements. Finally, we estimate the CMB--halo cross-correlation coefficient and show that it can be made to match that for CMB--dark matter to within 5% for thin redshift shells, mitigating the need to model bias evolution.Comment: 27 pages, 19 figure. Hi-res. version: http://www.itp.uzh.ch/~res/NonlinearISW.HiRes.pd

Tifus Murino en España durante el periodo 2004-2013

[ES] Objetivos: Estimar la incidencia y otros datos epidemiológicos del tifus murino en España. Material y métodos: Se analizaron aquellos pacientes cuyo diagnóstico al alta hospitalaria entre los años 2004-2013 se hubiera codificado en el CMBD, según el CIE 9-MC, como 081.0 (tifus endémico murino portado por pulgas). Resultados: Se diagnosticaron 56 pacientes (83,93% como diagnóstico principal y 16,07% como secundario) y 50 de ellos se detectaron en las Islas Canarias. La tasa de incidencia global por millón de habitantes y año, fue de 0,13 (IC95% de 0,10 a 0,17) en España. La media de edad fue de 49,75 años y un rango de 8-84 años. El riesgo relativo (RR) hombre-mujer fue 1,7:1. La mayoría de casos se concentraron en el tercer trimestre del año. Conclusiones: La incidencia del TM en España es baja y heterogénea. La enfermedad se detectó principalmente en Canarias, varones y el tercer trimestre del año.[EN] Objectives: To estimate the incidence and other epidemiological data of murine typhus in Spain. Material and methods: We analyzed those patients whose diagnosis at hospital discharge between 2004-2013 years had been coded in the Hospitalization Minimum Data Set, according to the ICD 9-MC, as 081.0 (Typhus, Endemic Flea-Borne). Main results: 56 patients were diagnosed (83.93% as main diagnosis and 16.07% as secondary) and 50 of them were detected in the Canary Islands. The global incidence rate per million inhabitants per year was 0.13 (CI95% from 0.10 to 0.17) in Spain.The mean age was 49.75 years and a range of 8-84 years. The relative risk (RR) male-female was 1.7: 1. The majority of cases were concentrated in the third quarter of the year. Conclusions: The incidence of TM in Spain is low and heterogeneous. The disease was detected mainly in the Canary Islands, males and the third quarter of the year.N

Frecuencia del consumo de drogas legales: Diferencias de edad en la adolescencia

El consumo de drogas es especialmente relevante por sus efectos negativos sobre la salud psicofísica y el funcionamiento social de los jóvenes. El objetivo de este estudio fue analizar las diferencias de edad respecto a las frecuencias de consumo de alcohol y tabaco en una muestra de 354 escolares (50.85% varones) de 12 a 18 años (M = 14.66; DT = 1.08) que cumplimentaron el Questionnarie about Consume of Alcohol and Tobacco (TNT). Los resultados muestran que el 82.4% de los adolescentes ha consumido bebidas alcohólicas en alguna ocasión y el 25.6% es consumidor actualmente. Respecto al consumo de tabaco, el 40.4% de estudiantes afirma haber fumado en alguna ocasión, siendo consumidores actuales el 8.2%. Asimismo, se hallaron diferencias estadísticamente significativas entre la adolescencia temprana y tardía, observándose un aumento sustancial del consumo actual de ambas sustancias con la edad. Estos resultados resaltan la importancia de la variable edad a la hora de planificar medidas preventivas y de promoción de la salud en población adolescente