1,469 research outputs found
Improving rainfall nowcasting and urban runoff forecasting through dynamic radar-raingauge rainfall adjustment
The insufficient accuracy of radar rainfall estimates is a major source of uncertainty in short-term quantitative precipitation forecasts (QPFs) and associated urban flood forecasts. This study looks at the possibility of improving QPFs and urban runoff forecasts through the dynamic adjustment of radar rainfall estimates based on raingauge measurements. Two commonly used techniques (Kriging with External Drift (KED) and mean field bias correction) were used to adjust radar rainfall estimates for a large area of the UK (250,000 km2) based on raingauge data. QPFs were produced using original radar and adjusted rainfall estimates as input to a nowcasting algorithm. Runoff forecasts were generated by feeding the different QPFs into the storm water drainage model of an urban catchment in London. The performance of the adjusted precipitation estimates and the associated forecasts was tested using local rainfall and flow records. The results show that adjustments done at too large scales cannot provide tangible improvements in rainfall estimates and associated QPFs and runoff forecasts at small scales, such as those of urban catchments. Moreover, the results suggest that the KED adjusted rainfall estimates may be unsuitable for generating QPFs, as this method damages the continuity of spatial structures between consecutive rainfall fields
Centro deportivo de la Universidad del Tolima "Plan de desarrollo de la Universidad del Tolima 2013 - 2022"
81 p. Recurso Electr?nicoLa Universidad del Tolima en su sede principal, cuenta con una unidad deportiva conformada por coliseo cubierto, coliseo alterno, tres canchas auxiliares (dos ubicadas en el parque Ducuara y otra en la Mar?a), y dos gimnasios, uno para estudiantes y otro para funcionarios, promoviendo el entrenamiento, entretenimiento, h?bitos de vida saludables, creaci?n y fortalecimiento de las relaciones interpersonales de los integrantes del campus y los sectores aleda?os.
Sin embargo, el crecimiento poblacional del departamento y por consiguiente del centro educativo, ha creado una problem?tica en cuanto a los escenarios deportivos y su limitaci?n diaria, generando congesti?n constante de los existentes e inevitable carencia de espacios adecuados f?sica y ambientalmente para el adecuado desarrollo integral del ser humano, as? como de su bienestar biopsicosocial.
Por lo planteando, se requiere inminentemente una soluci?n de infraestructura y de arquitectura que solucione y/o mitigue las necesidades surgentes, instaurando espacios suficientes y uniformes para los deportistas y asistentes recreativos, cuya composici?n arm?nica suscite una unidad deportiva que integre toda la poblaci?n y fortalezca el deporte en cuatro ?mbitos fundamentales para la Instituci?n: Como competencia, h?bito de vida saludable, estrategia para inclusi?n y/o re-inclusi?n social y mantenimiento y fortalecimiento de las relaciones interpersonales.The University of Tolima has a sports unit made up of a covered coliseum, an alternate coliseum, three auxiliary courts (two located in the Ducuara park and another in La Maria), and two gyms, one for students and another for staff , Promoting training, entertainment, healthy living habits, creating and strengthening the interpersonal relationships of campus members and surrounding sectors.
However, the population growth of the department and consequently of the educational center has created a problematic in terms of sports scenarios and their daily limitation, generating constant congestion of the existing ones and inevitable lack of adequate physical and environmental spaces for the adequate integral development Of the human being, as well as their biopsychosocial well-being.
Therefore, an infrastructure and architecture solution is urgently required to solve and / or mitigate the emerging needs, establishing sufficient and uniform spaces for athletes and recreational assistants, whose harmonious composition gives rise to a sports unit that integrates the entire population and strengthens Sport in four key areas for the Institution: as a competence, healthy life habit, strategy for inclusion and / or social re-inclusion and maintenance and strengthening of interpersonal relationships.
Keywords: modernization, social inclusion, University of Tolima
Physical realization of a quantum spin liquid based on a novel frustration mechanism
Unlike conventional magnets where the magnetic moments are partially or
completely static in the ground state, in a quantum spin liquid they remain in
collective motion down to the lowest temperatures. The importance of this state
is that it is coherent and highly entangled without breaking local symmetries.
Such phenomena is usually sought in simple lattices where antiferromagnetic
interactions and/or anisotropies that favor specific alignments of the magnetic
moments are "frustrated" by lattice geometries incompatible with such order
e.g. triangular structures. Despite an extensive search among such compounds,
experimental realizations remain very few. Here we describe the investigation
of a novel, unexplored magnetic system consisting of strong ferromagnetic and
weaker antiferromagnetic isotropic interactions as realized by the compound
CaCrO. Despite its exotic structure we show both
experimentally and theoretically that it displays all the features expected of
a quantum spin liquid including coherent spin dynamics in the ground state and
the complete absence of static magnetism.Comment: Modified version accepted in Nature Physic
VLA H92 Alpha and H53 Alpha Radio Recombination Line Observations of M82
We present high angular resolution (0.6'') observations made with the VLA of
the radio continuum at 8.3 and 43 GHz as well as H92 Alpha and H53 Alpha radio
recombination lines from the nearby (3 Mpc) starburst galaxy M82. In the
continuum we report 19 newly identified sources at 8.3 GHz and 5 at 43 GHz that
were unknown previously. The spatial distribution of the H92 Alpha line is
inhomogeneous; we identify 27 features. The line and continuum emission are
modeled using a collection of HII regions at different distances from the
nucleus assuming a single-density component and two-density components. The
high-density component has a density of 4 X 10^{4} cm^{-3}. However, the bulk
of the ionization is in regions with densities which are typically a factor 10
lower. The gas kinematics, using the H92 Alpha line, confirms the presence of
steep velocity gradient (26 km s^{-1} arcsec^{-1}) in the nuclear region. As
this steep gradient is observed not only on the major axis but also at large
distances along a band of PA of 150 degrees, the interpretation in terms of x2
orbits elongated along the minor axis of the bar, which would be observed at an
angle close to the inclination of the main disk, seems inadequate. Ad-hoc
radial motions must be introduced to reproduce the pattern of the velocity
field. Different families of orbits are indicated as we detect a signature in
the kinematics at the transition between the two plateaus observed in the NIR
light distribution. The H92 Alpha line also reveals the base of the outflow
where the injection towards the halo on the Northern side occurs. The
kinematical pattern suggests a connection between the gas flowing in the plane
of M82 towards the center; this behavior most likely originates due to the
presence of a bar and the outflow out of the plane.Comment: 45 pages, 11 figures and 6 tables. Accepted for publication in Ap
[S IV] in the NGC 5253 Supernebula: Ionized Gas Kinematics at High Resolution
The nearby dwarf starburst galaxy NGC 5253 hosts a deeply embedded
radio-infrared supernebula excited by thousands of O stars. We have observed
this source in the 10.5{\mu}m line of S+3 at 3.8 kms-1 spectral and 1.4"
spatial resolution, using the high resolution spectrometer TEXES on the IRTF.
The line profile cannot be fit well by a single Gaussian. The best simple fit
describes the gas with two Gaussians, one near the galactic velocity with FWHM
33.6 km s-1 and another of similiar strength and FWHM 94 km s-1 centered \sim20
km s-1 to the blue. This suggests a model for the supernebula in which gas
flows towards us out of the molecular cloud, as in a "blister" or "champagne
flow" or in the HII regions modelled by Zhu (2006).Comment: Accepted for publication in the Astrophysical Journal 4 June 201
The High-Density Ionized Gas in the Central Parsecs of the Galaxy
We report the results from observations of H30 line emission in Sgr A
West with the Submillimeter Array at a resolution of 2\arcsec and a field of
view of about 40\arcsec. The H30 line is sensitive to the high-density
ionized gas in the minispiral structure. We compare the velocity field obtained
from H30 line emission to a Keplerian model, and our results suggest
that the supermassive black hole at Sgr A* dominates the dynamics of the
ionized gas. However, we also detect significant deviations from the Keplerian
motion, which show that the impact of strong stellar winds from the massive
stars along the ionized flows and the interaction between Northern and Eastern
arms play significant roles in the local gas dynamics.Comment: 4 pages, 2 figure
The Optical Structure of the Starburst Galaxy M82. II. Nebular Properties of the Disk and Inner-Wind
(Abridged) In this second paper of the series, we present the results from
optical Gemini-North GMOS-IFU and WIYN DensePak IFU spectroscopic observations
of the starburst and inner wind zones of M82, with a focus on the state of the
T~10^4 K ionized interstellar medium. Our electron density maps show peaks of a
few 1000 cm-3, local small spatial-scale variations, and a fall-off in the
minor axis direction. We discuss the implications of these results with regards
to the conditions/locations that may favour the escape of individual cluster
winds. Our findings imply that the starburst environment is highly fragmented
into a range of clouds from small/dense clumps with low filling factors (<1pc,
n_e>10^4 cm-3) to larger filling factor, less dense gas. The near-constant
state of the ionization state of the ~10^4 K gas throughout the starburst can
be explained as a consequence of the small cloud sizes, which allow the gas
conditions to respond quickly to any changes. We have examined in more detail
both the broad (FWHM 150-350 km/s) line component found in Paper I that we
associated with emission from turbulent mixing layers on the gas clouds, and
the discrete outflow channel identified within the inner wind. The channel
appears as a coherent, expanding cylindrical structure of length >120 pc and
and width 35-50 pc and the walls maintain an approximately constant (but
subsonic) expansion velocity of ~60 km/s. We use the channel to examine further
the relationship between the narrow and broad component emitting gas within the
inner wind. Within the starburst energy injection zone, we find that turbulent
motions (as traced by the broad component) appear to play an increasing role
with height.Comment: 27 pages, 18 figures (13 in colour), accepted for publication in Ap
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