Respirando en la cima del mundo

Desde la antigüedad, el hombre se ha sentido atraído por la superación de los obstáculos naturales y por la exploración de lo desconocido, tanto en la geografía como en la ciencia. Es posible que las emociones de un montañista que alcanza su cumbre y las de un científico que llega a su descubrimiento sean muy similares. Para quien haya hecho sus intentos en cualquiera de estos campos, es factible evocarlas, aunque resulta difícil imaginar la suma de ambas. Quizás habría que preguntar a los investigadores de la expedición Caudwell Xtreme Everest (CXE), así como a sus predecesores, que consiguieron ambas metas. CXE es una mega-expedición científica que involucró a más de 200 montañistas y científicos instalados entre abril y mayo de 2007 en el pico más alto del mundo, con la intención de recabar múltiples datos fisiológicos en tan difíciles condiciones. Resulta admirable el esfuerzo logístico de semejante expedición, que involucró la instalación de varias toneladas de equipo técnico y médico y el transporte de muestras entre campamentos.Fil: de Vito, Eduardo. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Arce, Santiago C.. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; Argentin

Functional respiratory evolution in two patients with emphysema and pulmonary fibrosis

La combinación de enfisema y fibrosis pulmonar es una condición frecuentemente subdiagnosticada. Los estudios funcionales aislados pueden generar interpretaciones inadecuadas. No hemos hallado comunicaciones de casos que documenten la evolución espirométrica de estos pacientes. Se presentan dos casos de fibrosis y enfisema combinados que permiten observar la evolución funcional a largo plazo y comprender los valores espirométricos actuales en forma más precisa. Los hallazgos más relevantes son: 1) espirometría con discretas alteraciones funcionales en presencia de disnea marcada y, en un paciente, necesidad de oxigenoterapia crónica, 2) evolución funcional con seudonormalización del patrón espirométrico obstructivo inicial, posiblemente como consecuencia del desarrollo de fibrosis. Un defecto obstructivo leve en un paciente con diagnóstico de obstrucción crónica al flujo aéreo y marcado deterioro de su condición clínica y clase funcional debería alertar sobre la posibilidad de fibrosis pulmonar asociada. La tomografía y la disponibilidad de estudios funcionales previos permiten comprender esta condición.Combined pulmonary fibrosis and emphysema (CPFE) is a frequently under-diagnosed condition. Isolated pulmonary function tests (PFT) can give rise to misinterpretations. We have found no reports on these patients’ spirometric progression. We describe two cases of CPFE, showing long-term functional evolution to have a more accurate understanding of current spirometric values. The most relevant findings are: 1) spirometry with discrete functional alterations in the presence of a marked dyspnea and the need, in one patient, for chronic oxygen therapy; and 2) functional evolution reflecting “pseudonormalisation” of the initial obstructive spirometric pattern, possibly as a result of fibrosis development. A mild obstructive defect in a patient with chronic airflow limitation and marked impairment of his/her clinical status and functional class should alert on the possibility of associated pulmonary fibrosis. A computed tomography (CT) and previous PFTs will allow a better understanding of this condition.Fil: Arce, Santiago C.. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Molinari, Luciana. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; Argentina. Hospital Británico de Buenos Aires; ArgentinaFil: de Vito, Eduardo. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentin

Warm SiO gas in molecular bullets associated with protostellar outflows

In this paper we present the first SiO multiline analysis (from J=2-1 to J=11-10) of the molecular bullets along the outflows of the Class 0 sources L1448-mm and L1157-mm, obtained through observations with IRAM and JCMT. We have computed the main physical parameters in each bullet and compared them with other tracers of warm and dense gas and with models for the SiO excitation in shocks. We find that the bullets close to L1448--mm, associated with high velocity gas, have higher excitation conditions (n(H2) ~ 10^{6} cm^{-3}, T > 500 K) with respect to the L1157 bullets (n(H2) ~1-5 10^{5} cm^{-3}, T ~ 100-300 K). In both the sources, there is a clear evidence of the presence of velocity components having different excitation conditions, with the denser and/or warmer gas associated with the gas at the higher speed. In L1448 the bulk of the emission is due to the high-excitation and high velocity gas, while in L1157 most of the emission comes from the low excitation gas at ambient velocity. The observed velocity-averaged line ratios are well reproduced by shocks with speeds v_s larger than ~ 30 km/s and densities ~ 10^{5} - 10^{6} cm^{-3}. Plane-parallel shock models, however, fail to predict all the observed line profiles and in particular the very similar profiles shown by both low and high excitation lines. The overall observations support the idea that the L1157 clumps are shock interaction events older than the L1448 bullets close to the driving source. In the latter objects, the velocity structure and the variations of physical parameters with the velocity resemble very closely those found in optical/IR jets near the protostar, suggesting that similar launching and excitation mechanisms are also at the origin of collimated jets seen at millimetre wavelengths.Comment: 11pages, 9 figures, A&A accepte

Low-extinction windows in the inner Galactic Bulge

We built K band extinction maps in the area of two candidate low-extinction windows in the inner Bulge: W0.2-2.1 at (l,b) = (0.25o,-2.15o), and W359.4-3.1 at (l,b) = (359.40o,-3.10o). We employed JHKs photometry from the 2MASS Point Source Catalog. Extinction values were determined by fitting the upper giant branch found in the present 2MASS Ks x J-Ks diagrams to a de-reddened bulge stellar population reference giant branch. We tested the method on the well known Baade's and Sgr I windows: the 2MASS mean extinction values in these fields agreed well with those of previous studies. We confirm the existence of low-extinction windows in the regions studied, as local minima in the A_K maps reaching A_K values about 2 standard deviations below the mean values found in the neighbouring areas. Schlegel et al.'s (1998) FIR extinction maps, which integrate dust contributions throughout the Galaxy, are structurally similar to those derived with 2MASS photometry in the two studied windows. We thus conclude that the dust clouds affecting the 2MASS and FIR maps in these directions are basically the same and are located on foreground of the bulk of bulge stars. However, the A_K absolute values differ significantly. In particular, the FIR extinction values for W359.4-3.1 are a factor ~1.45 larger than those derived from the 2MASS photometry. Possible explanations of this effect are discussed. The lower Galactic latitudes of the low-extinction windows W359.4-3.1 and W0.2-2.1, as compared to Baade's Window, make them promising targets for detailed studies of more central bulge regions.Comment: 8 pages, 10 figures, LaTeX, aa.cls. To appear in Astron. & Astroph., in pres

Anomalía de Ebstein de la válvula tricúspide. A propósito de un caso

Introducción. La anomalía de Ebstein constituye menos del 1% de todas las cardiopatías congénitas. Consiste en el desplazamiento inferior de la válvula tricúspide anómala hacia el ventrículo derecho. Reporte: Paciente varón de 8 años de edad, procedente de Trujillo, con diagnóstico de enfermedad de Ebstein al mes de edad, que ingresa por emergencia presentando cianosis y dolor torácico. Interpretación: En la anomalía de Ebstein la gravedad de los síntomas y el grado de cianosis dependen del grado de desplazamiento de la válvula tricúspide. Los síntomas pueden ser leves o no aparecer hasta la adolescencia o la edad adulta

Episodic molecular outflow in the very young protostellar cluster Serpens South

The loss of mass from protostars, in the form of a jet or outflow, is a necessary counterpart to protostellar mass accretion. Outflow ejection events probably vary in their velocity and/or in the rate of mass loss. Such `episodic´ ejection events have been observed during the Class 0 protostellar phase (the early accretion stage), and continue during the subsequent class I phase that marks the first one million years of star formation. Previously observed episodic-ejection sources were relatively isolated; however, the most common sites of star formation are clusters. Outflows link protostars with their environment and provide a viable source of turbulence that is necessary for regulating star formation in clusters, but it is not known how an accretion-driven jet or outflow in a clustered environment manifests itself in its earliest stage. This early stage is important in establishing the initial conditions for momentum and energy transfer to the environment as the protostar and cluster evolve. Here we report that an outflow from a very young class 0 protostar, at the hub of the very active and filamentary Serpens South protostellar cluster, shows unambiguous episodic events. The 12CO (J=2-1) emission from the protostar reveals 22 distinct features of outflow ejecta, the most recent having the highest velocity. The outflow forms bipolar lobes --- one of the first detectable signs of star formation --- which originate from the peak of 1-mm continuum emission. Emission from the surrounding C18O envelope shows kinematics consistent with rotation and an infall of material onto the protostar. The data suggest that episodic accretion-driven outflow begins in the earliest phase of protostellar evolution, and that the outflow remains intact in a very clustered environment, probably providing efficient momentum transfer for driving turbulence. Fil: Plunkett, Adele L. . Yale University. Astronomy Department.; Estados UnidosFil: Arce, Héctor G.. Yale University. Astronomy Department.; Estados UnidosFil: Mardones, Diego . Universidad de Chile. Departamento de Astronomía; ChileFil: van Dokkum, Pieter . Yale University. Astronomy Department.; Estados UnidosFil: Dunham, Michael M. . Harvard-Smithsonian Center for Astrophysics; Estados UnidosFil: Fernandez Lopez, Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Instituto Argentino de Radioastronomia (i); ArgentinaFil: Gallardo, José. Joint ALMA Observatory; ChileFil: Cordero, Stuartt A. . Joint ALMA Observatory; Chil

Modelling Herschel observations of hot molecular gas emission from embedded low-mass protostars

Aims. Young stars interact vigorously with their surroundings, as evident from the highly rotationally excited CO (up to Eup=4000 K) and H2O emission (up to 600 K) detected by the Herschel Space Observatory in embedded low-mass protostars. Our aim is to construct a model that reproduces the observations quantitatively, to investigate the origin of the emission, and to use the lines as probes of the various heating mechanisms. Methods. The model consists of a spherical envelope with a bipolar outflow cavity. Three heating mechanisms are considered: passive heating by the protostellar luminosity, UV irradiation of the outflow cavity walls, and C-type shocks along the cavity walls. Line fluxes are calculated for CO and H2O and compared to Herschel data and complementary ground-based data for the protostars NGC1333 IRAS2A, HH 46 and DK Cha. The three sources are selected to span a range of evolutionary phases and physical characteristics. Results. The passively heated gas in the envelope accounts for 3-10% of the CO luminosity summed over all rotational lines up to J=40-39; it is best probed by low-J CO isotopologue lines such as C18O 2-1 and 3-2. The UV-heated gas and the C-type shocks, probed by 12CO 10-9 and higher-J lines, contribute 20-80% each. The model fits show a tentative evolutionary trend: the CO emission is dominated by shocks in the youngest source and by UV-heated gas in the oldest one. This trend is mainly driven by the lower envelope density in more evolved sources. The total H2O line luminosity in all cases is dominated by shocks (>99%). The exact percentages for both species are uncertain by at least a factor of 2 due to uncertainties in the gas temperature as function of the incident UV flux. However, on a qualitative level, both UV-heated gas and C-type shocks are needed to reproduce the emission in far-infrared rotational lines of CO and H2O.Comment: 15 pages (+4 pages appendix), 20 figures, accepted by A&

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

Search for the Higgs boson produced in association with a W boson and decaying to four b-quarks via two spin-zero particles in pp collisions at 13 TeV with the ATLAS detector

This paper presents a dedicated search for exotic decays of the Higgs boson to a pair of new spin-zero particles, H → aa, where the particle a decays to b-quarks and has a mass in the range of 20–60 GeV. The search is performed in events where the Higgs boson is produced in association with a W boson, giving rise to a signature of a lepton (electron or muon), missing transverse momentum, and multiple jets from b-quark decays. The analysis is based on the full dataset of pp collisions at √s = 13 TeV recorded in 2015 by the ATLAS detector at the CERN Large Hadron Collider, corresponding to an integrated luminosity of 3.2 fb−1. No significant excess of events above the Standard Model prediction is observed, and a 95% confidence-level upper limit is derived for the product of the production cross section for pp → W H times the branching ratio for the decay H → aa → 4b. The upper limit ranges from 6.2 pb for an a-boson mass ma = 20 GeV to 1.5 pb for ma = 60 GeV

Discutindo a educação ambiental no cotidiano escolar: desenvolvimento de projetos na escola formação inicial e continuada de professores

A presente pesquisa buscou discutir como a Educação Ambiental (EA) vem sendo trabalhada, no Ensino Fundamental e como os docentes desta escola compreendem e vem inserindo a EA no cotidiano escolar., em uma escola estadual do município de Tangará da Serra/MT, Brasil. Para tanto, realizou-se entrevistas com os professores que fazem parte de um projeto interdisciplinar de EA na escola pesquisada. Verificou-se que o projeto da escola não vem conseguindo alcançar os objetivos propostos por: desconhecimento do mesmo, pelos professores; formação deficiente dos professores, não entendimento da EA como processo de ensino-aprendizagem, falta de recursos didáticos, planejamento inadequado das atividades. A partir dessa constatação, procurou-se debater a impossibilidade de tratar do tema fora do trabalho interdisciplinar, bem como, e principalmente, a importância de um estudo mais aprofundado de EA, vinculando teoria e prática, tanto na formação docente, como em projetos escolares, a fim de fugir do tradicional vínculo “EA e ecologia, lixo e horta”.Facultad de Humanidades y Ciencias de la Educació