58 research outputs found
Diseño y elaboración de material docente para el seguimiento virtual de Estadística, Muestreo Estadístico e Informática en GAP
La introducción de las tecnologías de la información y la comunicación en los procesos de enseñanza permite un nuevo concepto de alumno-usuario y cambios en el modelo de enseñanza-aprendizaje que nos llevan a una educación superior más flexible. Así, el marco espaciotemporal en el que el alumno desarrolla las actividades de aprendizaje puede ser el hogar, el puesto de trabajo o un centro con recursos para el aprendizaje (como las aulas de informática de libre acceso que pone a disposición del alumno la Universidad de Jaén (UJA)).Destacar que en Gestión y Administración Pública (GAP) se encuentra un elevado número de estudiantes que trabajan para la Administración y que se matriculan con el objetivo de promocionar en su trabajo. Se trata de alumnos que, en general, no pueden asistir diariamente a las clases presenciales y a los que ciertas asignaturas como las de estadística les suponen un gran esfuerzo. Estas situaciones han llevado a la demanda generalizada por parte de los estudiantes universitarios para que se introduzcan cambios en las estrategias didácticas y en los sistemas de comunicación y distribución de los materiales de aprendizaje.El diseño e implantación de campus virtuales ha supuesto un gran reto para la mayor parte de las universidades españolas. En particular, la UJA se encuentra inmersa en este proceso, dando respuestas de diversa índole entre las que se encuentran los programas de innovación docente. Nosotros estamos iniciando a nuestros alumnos en el uso de las TICs, facilitándoles el uso de recursos y las herramientas necesarias para adquirir conocimientos y destrezas en las asignaturas de estadística, muestreo estadístico e informática
Detecting a stochastic gravitational wave background with the Laser Interferometer Space Antenna
The random superposition of many weak sources will produce a stochastic
background of gravitational waves that may dominate the response of the LISA
(Laser Interferometer Space Antenna) gravitational wave observatory. Unless
something can be done to distinguish between a stochastic background and
detector noise, the two will combine to form an effective noise floor for the
detector. Two methods have been proposed to solve this problem. The first is to
cross-correlate the output of two independent interferometers. The second is an
ingenious scheme for monitoring the instrument noise by operating LISA as a
Sagnac interferometer. Here we derive the optimal orbital alignment for
cross-correlating a pair of LISA detectors, and provide the first analytic
derivation of the Sagnac sensitivity curve.Comment: 9 pages, 11 figures. Significant changes to the noise estimate
All-particle cosmic ray energy spectrum measured with 26 IceTop stations
We report on a measurement of the cosmic ray energy spectrum with the IceTop
air shower array, the surface component of the IceCube Neutrino Observatory at
the South Pole. The data used in this analysis were taken between June and
October, 2007, with 26 surface stations operational at that time, corresponding
to about one third of the final array. The fiducial area used in this analysis
was 0.122 km^2. The analysis investigated the energy spectrum from 1 to 100 PeV
measured for three different zenith angle ranges between 0{\deg} and 46{\deg}.
Because of the isotropy of cosmic rays in this energy range the spectra from
all zenith angle intervals have to agree. The cosmic-ray energy spectrum was
determined under different assumptions on the primary mass composition. Good
agreement of spectra in the three zenith angle ranges was found for the
assumption of pure proton and a simple two-component model. For zenith angles
{\theta} < 30{\deg}, where the mass dependence is smallest, the knee in the
cosmic ray energy spectrum was observed between 3.5 and 4.32 PeV, depending on
composition assumption. Spectral indices above the knee range from -3.08 to
-3.11 depending on primary mass composition assumption. Moreover, an indication
of a flattening of the spectrum above 22 PeV were observed.Comment: 38 pages, 17 figure
Integrated analysis of water quality from two rivers used for public supply in southern Brazil
Benthic macroinvertebrate community structure in a stream of the north-west region of Paraná State, Brazil
Produção de serapilheira e ciclagem de nutrientes de um reflorestamento e de uma floresta estacional semidecidual no sul do Brasil
Setting a baseline for global urban virome surveillance in sewage
The rapid development of megacities, and their growing connectedness across the world is becoming a distinct driver for emerging disease outbreaks. Early detection of unusual disease emergence and spread should therefore include such cities as part of risk-based surveillance. A catch-all metagenomic sequencing approach of urban sewage could potentially provide an unbiased insight into the dynamics of viral pathogens circulating in a community irrespective of access to care, a potential which already has been proven for the surveillance of poliovirus. Here, we present a detailed characterization of sewage viromes from a snapshot of 81 high density urban areas across the globe, including in-depth assessment of potential biases, as a proof of concept for catch-all viral pathogen surveillance. We show the ability to detect a wide range of viruses and geographical and seasonal differences for specific viral groups. Our findings offer a cross-sectional baseline for further research in viral surveillance from urban sewage samples and place previous studies in a global perspective
The Great Markarian 421 Flare of 2010 February: Multiwavelength Variability and Correlation Studies
We report on variability and correlation studies using multiwavelength observations of the blazar Mrk 421 during the month of 2010 February, when an extraordinary flare reaching a level of ∼27 Crab Units above 1 TeV was measured in very high energy (VHE) γ-rays with the Very Energetic Radiation Imaging Telescope Array System (VERITAS) observatory. This is the highest flux state for Mrk 421 ever observed in VHE γ-rays. Data are analyzed from a coordinated campaign across multiple instruments, including VHE γ-ray (VERITAS, Major Atmospheric Gamma-ray Imaging Cherenkov), high-energy γ-ray (Fermi-LAT), X-ray (Swift, Rossi X-ray Timing Experiment, MAXI), optical (including the GASP-WEBT collaboration and polarization data), and radio (Metsahovi, Owens Valley Radio Observatory, University of Michigan Radio Astronomy Observatory). Light curves are produced spanning multiple days before and after the peak of the VHE flare, including over several flare "decline" epochs. The main flare statistics allow 2 minute time bins to be constructed in both the VHE and optical bands enabling a cross-correlation analysis that shows evidence for an optical lag of ∼25-55 minutes, the first time-lagged correlation between these bands reported on such short timescales. Limits on the Doppler factor (δ ⪆ 33) and the size of the emission region (δ-1RB≲ 3.8 × 1013cm) are obtained from the fast variability observed by VERITAS during the main flare. Analysis of 10 minute binned VHE and X-ray data over the decline epochs shows an extraordinary range of behavior in the flux-flux relationship, from linear to quadratic to lack of correlation to anticorrelation. Taken together, these detailed observations of an unprecedented flare seen in Mrk 421 are difficult to explain with the classic single-zone synchrotron self-Compton model.</p
Effects of Age, Parity, Season of Calving, and Sire on Milk Yield of Carora Cows in Venezuela
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