The water supercooled regime as described by four common water models

The temperature scale of simple water models in general does not coincide with the natural one. Therefore, in order to make a meaningful evaluation of different water models a temperature rescaling is necessary. In this paper we introduce a rescaling using the melting temperature and the temperature corresponding to the maximum of the heat capacity to evaluate four common water models (TIP4P-Ew, TIP4P-2005, TIP5P-Ew and Six-Sites) in the supercooled regime. Although all the models show the same general qualitative behavior, the TIP5P-Ew appears as the best representation of the supercooled regime when the rescaled temperature is used. We also analyze, using thermodynamic arguments, the critical nucleus size for ice growth. Finally, we speculate on the possible reasons why atomistic models do not usually crystalize while the coarse grained mW model do crystallize.Comment: 8 pages, 8 figure

Proximal nested sampling with data-driven priors for physical scientists

Proximal nested sampling was introduced recently to open up Bayesian model selection for high-dimensional problems such as computational imaging. The framework is suitable for models with a log-convex likelihood, which are ubiquitous in the imaging sciences. The purpose of this article is two-fold. First, we review proximal nested sampling in a pedagogical manner in an attempt to elucidate the framework for physical scientists. Second, we show how proximal nested sampling can be extended in an empirical Bayes setting to support data-driven priors, such as deep neural networks learned from training data.Comment: 9 pages, 4 figure

Estudio de un evento de quema de biomasa en la región Centro-Norte de Argentina en Agosto de 2018, mediante el uso de sensores satelitales y mediciones en supercie

Este trabajo tiene como objetivo analizar la deteccion de quema de biomasa en la region centro-norte delterritorio Argentino, que involucra principalmente a las provincias de Chaco, Formosa, Tucuman, Santiago delEstero, Santa Fe y Cordoba, entre el 27 y el 30 de agosto de 2018, utilizando mediciones satelitales y terrestres.Los aerosoles provenientes de la de quema de biomasa son los que mas afectan a America del Sur. Anualmente,desde mediados de agosto a principios de noviembre, se producen importantes quemas de pastizales que tienen suorigen en la zona centro-norte de Argentina, Bolivia, Paraguay y centro de Brasil, generalmente provocados por elhombre luego de la cosecha, para la eliminacion de desechos producto de la actividad agrcola y la deforestacion.Estas quemas producen importantes columnas de humo que pueden viajar cientos de kilometros transportadas porlos vientos desde su origen, afectando la calidad de aire de una gran extension territorial. Se analizan medicionessatelitales de los sensores MODIS (AQUA-TERRA) y TROPOMI (Sentinel-5p), de las cuales se estudian paraeste evento las siguientes variables: el ndice de absorcion de aerosoles (AI), el espesor optico de aerosoles (AOD)y la columna total de dioxido de nitrogeno y monoxido de carbono. Ademas se presentan las capturas satelitalesdel area afectada, representadas en RGB color verdadero. Tambien se calculan las retrotrayectorias con el modeloHYSPLIT/NOAA y la circulacion de viento de la base de datos NCEP/NCAR. Complementariamente se analizanlas mediciones del sistema LIDAR instalado en CITEDEF Villa Martelli, Buenos Aires, para determinar la alturade las capas de humo que llegan a la region. Ademas, se evaluan los datos de espesor optico de aerosoles delas estaciones de AERONET/NASA de Buenos Aires, Cordoba y Tucuman y se calcula, para dichas estaciones,el Coeciente declasicar los aerosoles.Angstrom, parametro sensible al radio medio de las partculas en suspension, lo que permite.Fil: García Ferreyra, M. F.. Comision Nacional de Actividades Espaciales; ArgentinaFil: Della Ceca, L.. Red Argentina de Municipios; ArgentinaFil: Casasola, F. I.. Ministerio de Defensa; ArgentinaFil: Martorella, Evangelina. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; ArgentinaFil: Brusca, S.. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; ArgentinaFil: D'elia, Raul Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; ArgentinaFil: Pereyra, C.. Servicio Geográfico Militar; ArgentinaFil: Pereyra, A.. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; ArgentinaFil: Raponi, Marcelo Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; ArgentinaFil: Ristori, Pablo Roberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; ArgentinaFil: Otero, Lidia Ana. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; Argentina104 Reunión de la Asociación de Física ArgentinaSanta FeArgentinaAsociación de Física Argentin

GW150914: First search for the electromagnetic counterpart of a gravitational-wave event by the TOROS collaboration

We present the results of the optical follow-up conducted by the TOROS collaboration of the first gravitational-wave event GW150914. We conducted unfiltered CCD observations (0.35-1 micron) with the 1.5-m telescope at Bosque Alegre starting ~2.5 days after the alarm. Given our limited field of view (~100 square arcmin), we targeted 14 nearby galaxies that were observable from the site and were located within the area of higher localization probability. We analyzed the observations using two independent implementations of difference-imaging algorithms, followed by a Random-Forest-based algorithm to discriminate between real and bogus transients. We did not find any bona fide transient event in the surveyed area down to a 5-sigma limiting magnitude of r=21.7 mag (AB). Our result is consistent with the LIGO detection of a binary black hole merger, for which no electromagnetic counterparts are expected, and with the expected rates of other astrophysical transients.Comment: ApJ Letters, in pres

Microplastics and anthropogenic debris in rainwater from Bahia Blanca, Argentina

Concern about atmospheric microplastic (MP) contamination has increased in recent years. This study assessed the abundance of airborne anthropogenic particles, including MPs, deposited in rainfall in Bahia Blanca, southwest Buenos Aires, Argentina. Rainwater samples were collected monthly from March to December 2021 using an active wet-only collector consisting of a glass funnel and a PVC pipe that is only open during rain events. Results obtained show that all rain samples contained anthropogenic debris. The term “anthropogenic debris” is used to refer to the total number of particles as not all the particles found could be determined as plastic. Among all the samples, an average deposition of 77 ± 29 items (anthropogenic debris) m⁻²d⁻¹ was found. The highest deposition was observed in November (148 items m⁻²d⁻¹) while the lowest was found in March (46 items m⁻²d⁻¹). Anthropogenic debris ranged in size from 0.1 mm to 3.87 mm with the most abundant particles being smaller than 1 mm (77.8%). The dominant form of particles found were fibers (95%), followed by fragments (3.1%). Blue color predominated (37.2%) in the total number of samples, followed by light blue (23.3%) and black (21.7%). Further, small particles (<2 mm), apparently composed of mineral material and plastic fibers, were recognized. The chemical composition of suspected MPs was examined by Raman microscopy. The analysis of μ-Raman spectra confirmed the presence of polystyrene, polyethylene terephthalate, and polyethylene vinyl acetate fibers and provided evidence of fibers containing industrial additives such as indigo dye. This is the first assessment of MP pollution in rain in Argentina.Centro de Química Inorgánic

Psoriasis Patients Are Enriched for Genetic Variants That Protect against HIV-1 Disease

An important paradigm in evolutionary genetics is that of a delicate balance between genetic variants that favorably boost host control of infection but which may unfavorably increase susceptibility to autoimmune disease. Here, we investigated whether patients with psoriasis, a common immune-mediated disease of the skin, are enriched for genetic variants that limit the ability of HIV-1 virus to replicate after infection. We analyzed the HLA class I and class II alleles of 1,727 Caucasian psoriasis cases and 3,581 controls and found that psoriasis patients are significantly more likely than controls to have gene variants that are protective against HIV-1 disease. This includes several HLA class I alleles associated with HIV-1 control; amino acid residues at HLA-B positions 67, 70, and 97 that mediate HIV-1 peptide binding; and the deletion polymorphism rs67384697 associated with high surface expression of HLA-C. We also found that the compound genotype KIR3DS1 plus HLA-B Bw4-80I, which respectively encode a natural killer cell activating receptor and its putative ligand, significantly increased psoriasis susceptibility. This compound genotype has also been associated with delay of progression to AIDS. Together, our results suggest that genetic variants that contribute to anti-viral immunity may predispose to the development of psoriasis

Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences

The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & Nemésio 2007; Donegan 2008, 2009; Nemésio 2009a–b; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on 18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based researchers who signed it in the short time span from 20 September to 6 October 2016