196 research outputs found
Modern optical astronomy: technology and impact of interferometry
The present `state of the art' and the path to future progress in high
spatial resolution imaging interferometry is reviewed. The review begins with a
treatment of the fundamentals of stellar optical interferometry, the origin,
properties, optical effects of turbulence in the Earth's atmosphere, the
passive methods that are applied on a single telescope to overcome atmospheric
image degradation such as speckle interferometry, and various other techniques.
These topics include differential speckle interferometry, speckle spectroscopy
and polarimetry, phase diversity, wavefront shearing interferometry,
phase-closure methods, dark speckle imaging, as well as the limitations imposed
by the detectors on the performance of speckle imaging. A brief account is
given of the technological innovation of adaptive-optics (AO) to compensate
such atmospheric effects on the image in real time. A major advancement
involves the transition from single-aperture to the dilute-aperture
interferometry using multiple telescopes. Therefore, the review deals with
recent developments involving ground-based, and space-based optical arrays.
Emphasis is placed on the problems specific to delay-lines, beam recombination,
polarization, dispersion, fringe-tracking, bootstrapping, coherencing and
cophasing, and recovery of the visibility functions. The role of AO in
enhancing visibilities is also discussed. The applications of interferometry,
such as imaging, astrometry, and nulling are described. The mathematical
intricacies of the various `post-detection' image-processing techniques are
examined critically. The review concludes with a discussion of the
astrophysical importance and the perspectives of interferometry.Comment: 65 pages LaTeX file including 23 figures. Reviews of Modern Physics,
2002, to appear in April issu
Discovery of an orally active benzoxaborole prodrug effective in the treatment of Chagas disease in non-human primates
Trypanosoma cruzi, the agent of Chagas disease, probably infects tens of millions of people, primarily in Latin America, causing morbidity and mortality. The options for treatment and prevention of Chagas disease are limited and underutilized. Here we describe the discovery of a series of benzoxaborole compounds with nanomolar activity against extra- and intracellular stages of T. cruzi. Leveraging both ongoing drug discovery efforts in related kinetoplastids, and the exceptional models for rapid drug screening and optimization in T. cruzi, we have identified the prodrug AN15368 that is activated by parasite carboxypeptidases to yield a compound that targets the messenger RNA processing pathway in T. cruzi. AN15368 was found to be active in vitro and in vivo against a range of genetically distinct T. cruzi lineages and was uniformly curative in non-human primates (NHPs) with long-term naturally acquired infections. Treatment in NHPs also revealed no detectable acute toxicity or long-term health or reproductive impact. Thus, AN15368 is an extensively validated and apparently safe, clinically ready candidate with promising potential for prevention and treatment of Chagas disease
Validación de la Escala Breve de Optimismo Interactivo-G en México antes de la COVID-19
The primary objectives of this study were determining the construct, convergent, and discriminant validity of the Brief Interactive Optimism Scale-G (BIOS-G) in participants from six states of Mexico and estimating its internal consistency. In this study 3 289 Mexicans participated (2 028 men and 1 243 women). The average age was = 30.43 years and SD = 10.52. Confirmatory factor analysis (CFA) and multiple regression analysis (MRA) were applied. There were appropriate fit indexes (e. g., CFI = .99; RMSEA = .07.). Convergent validity showed ANR (3 289)=.52(p=<.01;d=medium), with the Satisfaction with Life Scale (SWLS) and the estimation of discriminant validity was r (3 289) r = -.19 with the Brief Scale for Assessing Anger Proneness (APS-G) (p = < .01; d = almost small), Alpha = .70 (3 289); p = < .01; omega = .76. The conclusion is that there is partial national evidence supporting the use of BIOS-G, because Mexico lacks a measure of this kind, being useful, at least, for research purposes.Los objetivos primarios del presente estudio fueron determinar la validez de constructo, convergente y discriminante de la Escala Breve de Optimismo Interactivo-G (EBOI-G), en participantes de seis estados de México y calcular su consistencia interna. Participaron 3289 mexicanos, 2028 hombres y 1243 mujeres (18 casos no contestaron cuál era su género). Su edad promedio = 30.43 años, de = 10.52. Se usó el análisis factorial confirmatorio y análisis de regresión múltiple, y se encontraron buenos indicadores promedio de bondad de ajuste (e. g., CFI = .99; RMSEA = .07.). Se evaluó la validez convergente, r (3 289) = .52 (p = < .01; d = mediano), con la Escala de Satisfacción con la Vida. Se estimó la validez discriminante, r (3 289) r = -.19, con la Escala Breve de Disposición a la IRA (p = < .01; d = casi pequeño). El alfa = .70 (3 289); p = < .01; el omega = .76. Se concluye que hay evidencia parcial nacional que apoya el uso de la EBOI-G, debido a la carencia de una medida de este tipo en México, útil cuando menos para propósitos de investigación.Os objetivos primários do estudo foram determinar a validade convergente e discriminante do construto da Escala Breve de Otimismo Interativo-G (EBOI-G), em participantes de seis estados do México e calcular sua consistência interna. Participaram 3 289 mexicanos, sendo 2 028 homens e 1 243 mulheres. A média de idade foi = 30.43 anos, DP = 10.52. Foram utilizadas análises fatoriais confirmatórias e análises de regressão múltipla. Bons indicadores médios de qualidade de ajuste foram encontrados (por exemplo, CFI = .99; RMSEA = .07.) A validade convergente foi avaliada, r (3 289) = .52 (p = <.01; d = mediana), com a Escala de satisfação com a vida. A validade discriminante, r (3 289) = -.19 foi estimada com a Escala Breve de Disposição à Raiva (p = <.01; d = quase pequeno). O alfa = 0,70 (3 289); p = <0,01; o ômega = 0,76. Conclui-se que há evidências nacionais parciais que apoiam o uso da EBOI-G, devido à falta de uma medida desse tipo no México, sendo útil pelo menos para fins de pesquisa
Administración de los servicios de salud de la Unidad Departamental de Salud Lima Ciudad, Hospital de Apoyo I Santa Rosa y Centros de Salud de Magdalena y San Miguel
El cuidado de la salud constituye un imperativo categórico para ser considerada como una prioridad impostergable, ya que el poblador sano está en aptitud de conformar una población económicamente activa, que contribuirá al desarrollo Y fortalecimiento de la Sociedad. Este concepto, llevó a muchos países en desarrollo a crear vastos sistemas de atención de la salud financiados por el sector público, gratuitos o a bajo costo. La crisis financiera de los ochenta obligó a muchos de estos países a disminuir sus presupuestos en los servicios de salud. entre estos el Perú ha atravesado cíclicamente por etapas críticas, pero ninguna tan seria y prolongada como la presente, con un grave deterioro social, político y administrativo. Lo que ha llevado a una degradación de las condiciones de vida de la mayor parte de la población, conformada por los sectores populares de menores recursos y ahora por la clase media, conducidos a situaciones de extrema pobreza (45 % de la población); esto obligó a realizar ajustes económicos drásticos Y restringir los gastos sociales del gobierno. La disminución sustancial en los gastos del gobierno en lo referente al sector salud, ha producido un deterioro gradual y sustancial en los servicios de salud y por lo tanto en la situación de salud del país; esto ha incentivado al Ministerio de Salud a plantear politices orientadas a concebir Estrategias que tengan un alto grado de sustentación que permitan desarrollar planee de salud a corto, mediano y largo plazo que sean consistentes y factibles de ser ejecutados. Por lo que el estudio de la administración de salud y su problemática, como factor coadyuvante en el deterioro de los servicios de salud, cobra gran importancia para el planteamiento de soluciones que permitan redefinir los lineamientos de la política de salud.Trabajo académic
Inside the Outbreak of the 2009 Influenza A (H1N1)v Virus in Mexico
Influenza viruses pose a threat to human health because of their potential to cause global disease. Between mid March and mid April a pandemic influenza A virus emerged in Mexico. This report details 202 cases of infection of humans with the 2009 influenza A virus (H1N1)v which occurred in Mexico City as well as the spread of the virus throughout the entire country.From May 1st to May 5th nasopharyngeal swabs, derived from 751 patients, were collected at 220 outpatient clinics and 28 hospitals distributed throughout Mexico City. Analysis of samples using real time RT-PCR revealed that 202 patients out of the 751 subjects (26.9%) were confirmed to be infected with the new virus. All confirmed cases of human infection with the strain influenza (H1N1)v suffered respiratory symptoms. The greatest number of confirmed cases during the outbreak of the 2009 influenza A (H1N1)v were seen in neighbourhoods on the northeast side of Mexico City including Iztapalapa, Gustavo A. Madero, Iztacalco, and Tlahuac which are the most populated areas in Mexico City. Using these data, together with data reported by the Mexican Secretariat of Health (MSH) to date, we plot the course of influenza (H1N1)v activity throughout Mexico.Our data, which is backed up by MSH data, show that the greatest numbers of the 2009 influenza A (H1N1) cases were seen in the most populated areas. We speculate on conditions in Mexico which may have sparked this flu pandemic, the first in 41 years. We accept the hypothesis that high population density and a mass gathering which took in Iztapalapa contributed to the rapid spread of the disease which developed in three peaks of activity throughout the Country
Knockout of the dhfr-ts Gene in Trypanosoma cruzi Generates Attenuated Parasites Able to Confer Protection against a Virulent Challenge
Chagas disease is the clinical manifestation of the infection produced by the flagellate parasite Trypanosoma cruzi and currently there is no vaccine to prevent this disease. Therefore, different approaches or alternatives are urgently needed. Vaccination with live attenuated parasites has been used effectively in mice to reduce parasitemia and histological damage. However, the use of live parasites as inmunogens is controversial due to the risk of reversion to a virulent phenotype. In this work we genetically manipulated a naturally attenuated strain of T. cruzi in order to produce parasites with impaired replication and infectivity, using the mutation as a safety device against reversion to virulence. We show that genetically modified parasites display a lower proliferation rate in vitro and induced almost undetectable levels of T. cruzi specific CD8+ T cells when injected in mice. Furthermore, the immune response induced by these live mutant parasites confers protection against a subsequent virulent infection even a year after the original immunization
Regulation of cell death receptor S-nitrosylation and apoptotic signaling by Sorafenib in hepatoblastoma cells
Nitric oxide (NO) plays a relevant role during cell death regulation in tumor cells. The overexpression of nitric oxide synthase type III (NOS-3) induces oxidative and nitrosative stress, p53 and cell death receptor expression and apoptosis in hepatoblastoma cells. S-nitrosylation of cell death receptor modulates apoptosis. Sorafenib is the unique recommended molecular-targeted drug for the treatment of patients with advanced hepatocellular carcinoma. The present study was addressed to elucidate the potential role of NO during Sorafenib-induced cell death in HepG2 cells. We determined the intra- and extracellular NO concentration, cell death receptor expression and their S-nitrosylation modifications, and apoptotic signaling in Sorafenib-treated HepG2 cells. The effect of NO donors on above parameters has also been determined. Sorafenib induced apoptosis in HepG2 cells. However, low concentration of the drug (10nM) increased cell death receptor expression, as well as caspase-8 and -9 activation, but without activation of downstream apoptotic markers. In contrast, Sorafenib (10 µM) reduced upstream apoptotic parameters but increased caspase-3 activation and DNA fragmentation in HepG2 cells. The shift of cell death signaling pathway was associated with a reduction of S-nitrosylation of cell death receptors in Sorafenib-treated cells. The administration of NO donors increased S-nitrosylation of cell death receptors and overall induction of cell death markers in control and Sorafenib-treated cells. In conclusion, Sorafenib induced alteration of cell death receptor S-nitrosylation status which may have a relevant repercussion on cell death signaling in hepatoblastoma cells.Instituto de Salud Carlos III PI13/00021Ministerio de Economía y Competitividad BFU2012-32056Consejería de Economía, Innovación, Ciencia y Empleo, Junta de Andalucía BIO-0216Consejería de Economía, Innovación, Ciencia y Empleo, Junta de Andalucía CTS-6264Consejería de Salud, Junta de Andalucía PI13/ 0002
LSST Science Book, Version 2.0
A survey that can cover the sky in optical bands over wide fields to faint
magnitudes with a fast cadence will enable many of the exciting science
opportunities of the next decade. The Large Synoptic Survey Telescope (LSST)
will have an effective aperture of 6.7 meters and an imaging camera with field
of view of 9.6 deg^2, and will be devoted to a ten-year imaging survey over
20,000 deg^2 south of +15 deg. Each pointing will be imaged 2000 times with
fifteen second exposures in six broad bands from 0.35 to 1.1 microns, to a
total point-source depth of r~27.5. The LSST Science Book describes the basic
parameters of the LSST hardware, software, and observing plans. The book
discusses educational and outreach opportunities, then goes on to describe a
broad range of science that LSST will revolutionize: mapping the inner and
outer Solar System, stellar populations in the Milky Way and nearby galaxies,
the structure of the Milky Way disk and halo and other objects in the Local
Volume, transient and variable objects both at low and high redshift, and the
properties of normal and active galaxies at low and high redshift. It then
turns to far-field cosmological topics, exploring properties of supernovae to
z~1, strong and weak lensing, the large-scale distribution of galaxies and
baryon oscillations, and how these different probes may be combined to
constrain cosmological models and the physics of dark energy.Comment: 596 pages. Also available at full resolution at
http://www.lsst.org/lsst/sciboo
The Fourteenth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the extended Baryon Oscillation Spectroscopic Survey and from the second phase of the Apache Point Observatory Galactic Evolution Experiment
The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) has been in
operation since July 2014. This paper describes the second data release from
this phase, and the fourteenth from SDSS overall (making this, Data Release
Fourteen or DR14). This release makes public data taken by SDSS-IV in its first
two years of operation (July 2014-2016). Like all previous SDSS releases, DR14
is cumulative, including the most recent reductions and calibrations of all
data taken by SDSS since the first phase began operations in 2000. New in DR14
is the first public release of data from the extended Baryon Oscillation
Spectroscopic Survey (eBOSS); the first data from the second phase of the
Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE-2),
including stellar parameter estimates from an innovative data driven machine
learning algorithm known as "The Cannon"; and almost twice as many data cubes
from the Mapping Nearby Galaxies at APO (MaNGA) survey as were in the previous
release (N = 2812 in total). This paper describes the location and format of
the publicly available data from SDSS-IV surveys. We provide references to the
important technical papers describing how these data have been taken (both
targeting and observation details) and processed for scientific use. The SDSS
website (www.sdss.org) has been updated for this release, and provides links to
data downloads, as well as tutorials and examples of data use. SDSS-IV is
planning to continue to collect astronomical data until 2020, and will be
followed by SDSS-V.Comment: SDSS-IV collaboration alphabetical author data release paper. DR14
happened on 31st July 2017. 19 pages, 5 figures. Accepted by ApJS on 28th Nov
2017 (this is the "post-print" and "post-proofs" version; minor corrections
only from v1, and most of errors found in proofs corrected
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