The accretion disk in the post period-minimum cataclysmic variable SDSS J080434.20+510349.2

This study of SDSS0804 is primarily concerned with the double-hump shape in the light curve and its connection with the accretion disk in this bounce-back system. Time-resolved photometric and spectroscopic observations were obtained to analyze the behavior of the system between superoutbursts. A geometric model of a binary system containing a disk with two outer annuli spiral density waves was applied to explain the light curve and the Doppler tomography. Observations were carried out during 2008-2009, after the object's magnitude decreased to V~17.7(0.1) from the March 2006 eruption. The light curve clearly shows a sinusoid-like variability with a 0.07 mag amplitude and a 42.48 min periodicity, which is half of the orbital period of the system. In Sept. 2010, the system underwent yet another superoutburst and returned to its quiescent level by the beginning of 2012. This light curve once again showed a double-humps, but with a significantly smaller ~0.01mag amplitude. Other types of variability like a "mini-outburst" or SDSS1238-like features were not detected. Doppler tomograms, obtained from spectroscopic data during the same period of time, show a large accretion disk with uneven brightness, implying the presence of spiral waves. We constructed a geometric model of a bounce-back system containing two spiral density waves in the outer annuli of the disk to reproduce the observed light curves. The Doppler tomograms and the double-hump-shape light curves in quiescence can be explained by a model system containing a massive >0.7Msun white dwarf with a surface temperature of ~12000K, a late-type brown dwarf, and an accretion disk with two outer annuli spirals. According to this model, the accretion disk should be large, extending to the 2:1 resonance radius, and cool (~2500K). The inner parts of the disk should be optically thin in the continuum or totally void.Comment: 12 pages, 15 figures, accepted for publication in A&

Star Formation in a Stellar Mass Selected Sample of Galaxies to z=3 from the GOODS NICMOS Survey (GNS)

We present a study of the star-forming properties of a stellar mass-selected sample of galaxies in the GOODS NICMOS Survey (GNS), based on deep Hubble Space Telescope imaging of the GOODS North and South fields. Using a stellar mass selected sample, combined with HST/ACS and Spitzer data to measure both UV and infrared derived star formation rates (SFR), we investigate the star forming properties of a complete sample of ~1300 galaxies down to log M*=9.5 at redshifts 1.5<z<3. Eight percent of the sample is made up of massive galaxies with M*>10^11 Msun. We derive optical colours, dust extinctions, and ultraviolet and infrared SFR to determine how the star formation rate changes as a function of both stellar mass and time. Our results show that SFR increases at higher stellar mass such that massive galaxies nearly double their stellar mass from star formation alone over the redshift range studied, but the average value of SFR for a given stellar mass remains constant over this 2 Gyr period. Furthermore, we find no strong evolution in the SFR for our sample as a function of mass over our redshift range of interest, in particular we do not find a decline in the SFR among massive galaxies, as is seen at z < 1. The most massive galaxies in our sample (log M*>11) have high average SFRs with values, SFR(UV,corr) = 103+/-75 Msun/yr, yet exhibit red rest-frame (U-B) colours at all redshifts. We conclude that the majority of these red high-redshift massive galaxies are red due to dust extinction. We find that A(2800) increases with stellar mass, and show that between 45% and 85% of massive galaxies harbour dusty star formation. These results show that even just a few Gyr after the first galaxies appear, there are strong relations between the global physical properties of galaxies, driven by stellar mass or another underlying feature of galaxies strongly related to the stellar mass.Comment: 18 pages, 10 figures, accepted for publication in MNRA

Dermatomicosis en población de Manizales

This is a report of the mycological study of 1,175 adult patients treate by Manizales medical cervices. It was possible to confirm a positive diagnosis in 779 patients (66,3%), with 72 (6,1%) occurrences of Pityriasis versicolor, 1 (0,1%) of Tinnea nigra palmaris, 291 (24,8%) of dermato-phyticcutaneous mycosisand 184 (15,7%) casesofcandidiasis. The frequency distribution includes 15 Microsporum, 101 Epidermophyton and 257 Tricophyton. The epidemiologic classification includes the following groups of fungi: antropophylic 357 (95,7%), geophytlic 10 (2,7%) and zoophylic 6 (1,6%). The most commonly found species were: M. canis, M. gypseum, E. floccosum, T. rubrum, T. mentagrophytes, T. tonsurans, T. verrucosum, Cladosporium werneckkii, and Malassezia furfur. This report describes the fungi isolated in dystrophic nails as follows: dermatophytes 82 (7,0%) and Candida albicans 103 (8,8%). In 46 (3,9%) patients nordermatophytes were cultured and incriminated as opportunistic pathogens according to several authors. In 10 (0,8%) samples, no etiological diagnosis was obtained because of the growth of Mycelia sterila. No growth ocurred in 386 (32,8%) cultures. This article presents an overview of the laboratory procedures and some general considerations concerning the pathology of dermatophytes.Se informa sobre el estudio micológico realizado en una población de 1.175 pacientes adultos remitidos por el servicio médico de la ciudad de Manizales. Fue posible establecer diagnóstico positivo en 779 pacientes (66,3%), con 72 (6,1%) casos de pitiriasis versicolor, 1 (0,1%) por Tineanigrapalmaris, 291 (24,8%) micosiscutáneaspordermatofitos y 184 (15,7%) casos de candidiasis. La distribución de frecuencia agrupó a 15 Microsporum, 101 Epidermophyton y 257 Trichophyton. Fueron 357 (95,7%) antropofílicos, 10 (2,7%) geofílicos y 6 (1,6%) zoofílicos. Las especies aisladas fueron: M. canis, M. gypseum, E. floccosum, T. rubrum, T. mentagrophytes, T. tonsurans, T. verrucosum, Cladosporium werneckii, Malassezia furtur y otros. En el estudio de las onicopatías se encontraron: 82 (7,0%) casos por dermatofitos 103 (8,8%) casos por Candida albicans; en 46 (3,9%) casos se aislaron hongos no dermatofitos incriminados como agentes patógenos oportunistas, por algunos autores. No hubo diagnóstico micológico en 10 (0,8%) casos por obtenerse en los cultivos Mycelia sterilla, y fueron negativos 386 (32,8%). Se indican los procedimientos paraanálisis micológico y se mencionan consideraciones generales sobre la patología de la dermatofitos

On the nature of the hard X-ray sources SWIFTJ1907.3-2050, IGRJ12123-5802 and IGRJ19552+0044

The INTEGRAL and Swift hard X-ray surveys have identified a large number of new sources, among which many are proposed as Cataclysmic Variables (CVs). Here we present the first detailed study of three X-ray selected CVs, Swift J1907.3-2050, IGRJ12123-5802, and IGRJ19552+0044 based on XMM-Newton, Suzaku, Swift observations and ground based optical and archival nIR/IR data. Swift J1907.3-2050 is highly variable from hours to months-years at all wavelengths. No coherent X-ray pulses are detected but rather transient features. The X-ray spectrum reveals a multi-temperature optically thin plasma absorbed by complex neutral material and a soft black body component arising from a small area. These characteristics are remarkably similar to those observed in magnetic CVs. A supra-solar abundance of nitrogen could arise from nuclear processed material from the donor star. Swift J1907.3-2050 could be a peculiar magnetic CV with the second longest (20.82 h) binary period. IGRJ12123-5802 is variable in the X-rays on a timescale of ~7.6 h. No coherent pulsations are detected, but its spectral characteristics suggest that it could be a magnetic CV of the Intermediate Polar (IP) type. IGRJ19552+0044 shows two X-ray periods, 1.38 h and 1.69 h and a X-ray spectrum characterized by a multi-temperature plasma with little absorption.We derive a low accretion rate, consistent with a CV below the orbital period gap. Its peculiar nIR/IR spectrum suggests a contribution from cyclotron emission. It could either be a pre-polar or an IP with the lowest degree of asynchronism.Comment: Accepted for publication in MNRAS. 14 pages, 11 figures, 5 table

Theoretical And Methodological Proposal For The Articulation Of The Components Of The Environmental Dimension In The Curriculum Structure Of The Environmental Engineering Program.

RESUMEN. La incorporación de la dimensión ambiental en la educación superior en el país, se ha relacionado generalmente con el manejo de los fenómenos naturales, representado en los cursos de ecología en los planes de estudio, sin establecer relaciones con el componente sociocultural (Leff, 1998; Ángel, 1997; Bermúdez, 2003). En el caso de los programas de Ingeniería ambiental, se ha entendido como incorporación ambiental en esta carrera, la introducción de cátedras sobre contaminación y de tecnologías para su manejo (Ángel, 1997). Pero la formación del ingeniero ambiental exige incluir la dimensión ambiental con su complejidad, es decir abordando las relaciones existentes entre la sociedad y la naturaleza (Ángel, 1997; Bermúdez, 2003; Torres, 1996), dicha complejidad no se recoge en la formación ambiental para el caso particular del programa de ingeniería ambiental de la UCEVA. Esta investigación explora la manera de lograr la articulación entre el sistema natural y el sociocultural de la dimensión ambiental presente en la estructura curricular del programa académico de Ingeniería Ambiental de la UCEVA, conllevando a que se proponga como una manera de lograr esta articulación, y de aportar en aspectos fundamentales para el desarrollo del currículo, el estudio de las relaciones entre ciencia, tecnología, sociedad y ambiente (CTSA), tomando los problemas ambientales como ejes centrales en el desarrollo del currículo de los programas de ingeniería ambiental, los cuales son estudiados desde diversas miradas, permitiendo el trabajo interdisciplinar por medio del análisis de las interacciones de la naturaleza y el sistema socio-cultural. SUMMARY. Incorporating the environmental dimension in higher education in the country, has been linked generally with the management of natural phenomena, represented in ecology courses in the curriculum, without establishing relations with the sociocultural component (Leff, 1998; Ángel, 1997; Bermúdez, 2003). In the case of environmental engineering programs, has been perceived as environmental mainstreaming in this race, the introduction of lectures on pollution and its management technologies (Ángel, 1997). But environmental engineering education required to include the environmental dimension to their complexity, ie dealing with the relations between society and nature (Angel Bermudez Torres), this complexity is not included in the environmental training for the particular case of the program Environmental engineering UCEVA. This research explores how to achieve a link between the natural and socio-cultural system of the environmental dimension present in the curricular structure of the academic program UCEVA Environmental Engineering, to eventually be proposed as a way to achieve this articulation, and to contribute in key areas for curriculum development, the study of relations between science, technology, society and environment (STSE), taking environmental issues as central in the development of curriculum for environmental engineering programs, which are studied from different looks, allowing interdisciplinary work through the analysis of the interactions of nature and the socio-cultural

Self-trapping of a binary Bose-Einstein condensate induced by interspecies interaction

The problem of self-trapping of a Bose-Einstein condensate (BEC) and a binary BEC in an optical lattice (OL) and double well (DW) is studied using the mean-field Gross-Pitaevskii equation. For both DW and OL, permanent self-trapping occurs in a window of the repulsive nonlinearity $g$ of the GP equation: $g_{c1}<g<g_{c2}$. In case of OL, the critical nonlinearities $g_{c1}$ and $g_{c2}$ correspond to a window of chemical potentials $\mu_{c1}<\mu<\mu_{c2}$ defining the band gap(s) of the periodic OL. The permanent self-trapped BEC in an OL usually represents a breathing oscillation of a stable stationary gap soliton. The permanent self-trapped BEC in a DW, on the other hand, is a dynamically stabilized state without any stationary counterpart. For a binary BEC with intraspecies nonlinearities outside this window of nonlinearity, a permanent self trapping can be induced by tuning the interspecies interaction such that the effective nonlinearities of the components fall in the above window

The Progenitors of Local Ultra-massive Galaxies Across Cosmic Time: from Dusty Star-bursting to Quiescent Stellar Populations

Using the UltraVISTA catalogs, we investigate the evolution in the 11.4~Gyr since $z=3$ of the progenitors of local ultra-massive galaxies ($\log{(M_{\rm star}/M_{\odot})}\approx11.8$; UMGs), providing a complete and consistent picture of how the most massive galaxies at $z=0$ have assembled. By selecting the progenitors with a semi-empirical approach using abundance matching, we infer a growth in stellar mass of 0.56$^{+0.35}_{-0.25}$ dex, 0.45$^{+0.16}_{-0.20}$~dex, and 0.27$^{+0.08}_{-0.12}$ dex from $z=3$, $z=2$, and $z=1$, respectively, to $z=0$. At $z<1$, the progenitors of UMGs constitute a homogeneous population of only quiescent galaxies with old stellar populations. At $z>1$, the contribution from star-forming galaxies progressively increases, with the progenitors at $2<z<3$ being dominated by massive ($M_{\rm star} \approx 2 \times 10^{11}$M$_{\odot}$), dusty ($A_{\rm V}\sim$1--2.2 mag), star-forming (SFR$\sim$100--400~M$_{\odot}$ yr$^{-1}$) galaxies with a large range in stellar ages. At $z=2.75$, $\sim$15\% of the progenitors are quiescent, with properties typical of post-starburst galaxies with little dust extinction and strong Balmer break, and showing a large scatter in color. Our findings indicate that at least half of the stellar content of local UMGs was assembled at $z>1$, whereas the remaining was assembled via merging from $z\sim 1$ to the present. Most of the quenching of the star-forming progenitors happened between $z=2.75$ and $z=1.25$, in good agreement with the typical formation redshift and scatter in age of $z=0$ UMGs as derived from their fossil records. The progenitors of local UMGs, including the star-forming ones, never lived on the blue cloud since $z=3$. We propose an alternative path for the formation of local UMGs that refines previously proposed pictures and that is fully consistent with our findings.Comment: 20 pages, 15 figures (6 of which in appendix); accepted for publication in the Astrophysical Journa