330 research outputs found
Service level agreement framework for differentiated survivability in GMPLS-based IP-over-optical networks
In the next generation optical internet, GMPLS based IP-over-optical networks, ISPs will be required to support a wide variety of applications each having their own requirements. These requirements are contracted by means of the SLA. This paper describes a recovery framework that may be included in the SLA contract between ISP and customers in order to provide the required level of survivability. A key concern with such a recovery framework is how to present the different survivability alternatives including recovery techniques, failure scenario and layered integration into a transparent manner for customers. In this paper, two issues are investigated. First, the performance of the recovery framework when applying a proposed mapping procedure as an admission control mechanism in the edge router considering a smart-edge simple-core GMPLS-based IP/WDM network is considered. The second issue pertains to the performance of a pre-allocated restoration and its ability to provide protected connections under different failure scenarios
Contenido de Cadmio y Plomo en tejido de Hígado y Riñón en el Jote de Cabeza Colorada Cathartes aura (Linneo, 1758) de Chañaral, Desierto de Atacama, Chile
Indexación: Web of Science; ScieloThe Atacama region, Chile, presents one of the highest levels of mining exploitation of the country, which leads to high levels of contamination from mine tailings and other related environmental liabilities. One of the most complex situations occurred in the Chañaral city, north of Chile, where for over 50 years mine tailings were dumped on the coast, causing severe damage in the ecosystem. To evaluate the effects on terrestrial biota, we analyzed the concentration of cadmium and lead in tissues of Turkey Vulture (Cathartes aura). The results indicate that accumulation of cadmium in kidney was 10.31 μg/g (SD 8.00, range 0.27 to 20.73 μg/g) while in the liver was 5.24 μg/g (SD 8.00, range 0.49 to 19.70). There values are very high when compared to data for other birds with similar ecological role. In relation to the lead, concentration in liver was 0.86 μg/g (SD 2.03, range 0.15 - 7.90), while in kidney was 1.05 μg/g (DS 2.54, range 0.044 to 9.86), values considered within the normal range. It is interesting to analyze from the perspective of the availability of these metals in the mining tailings, where lead (1.57 to 21.2 μg/g) presented higher levels than cadmium (0.061 to 1.085 μg/g). The difference between organs may be related to the role of metallothionein. We discuss the role of Turkey Vulture as a bioindicator of environmental liabilities.La Región de Atacama, Chile, presenta uno de los mayores niveles de explotación minera del país, el cual a su vez genera altos niveles de contaminación por relaves mineros y otros pasivos ambientales relacionados. Una de las más complejas situaciones ocurrió en la ciudad de Chañaral, norte de Chile, donde fueron liberados relaves mineros a sus costas por sobre 50 años, causando graves daños en el ecosistema. Para evaluar los efectos en la biota terrestre, nosotros analizamos la concentración de Cadmio y Plomo en tejidos del Jote de Cabeza Colorada (Cathartes aura). Los resultados indican que la acumulación de Cadmio en el Riñón fue 10,31 μg/g (DS 8,00, rango 0,27 a 20,73 μg/g) mientras en el Hígado fue 5,24 μg/g (DS 8,00, rango 0,49 a 19,70). Estos valores son muy altos si se compara con datos de otras aves de similar rol ecológico. En relación al Plomo, la concentración en Hígado fue de 0,86 μg/g (DS 2,03, rango 0,15 a 7,90), mientras que en Riñón fue de 1,05 μg/g (DS 2,54, rango 0,044 a 9,86), valores considerados dentro del rango normal. Estos resultados son interesantes de analizar desde la perspectiva de la disponibilidad de estos metales en el relave minero, donde el Plomo (1,57 a 21,2 μg/g) presentó mayores niveles que el Cadmio (0,061 a 1,085 μg/g). La diferencia entre órganos puede ser relacionado al rol de las metalotioneinas. Discutimos el rol del Jote de Cabeza Colorada como bioindicador de contaminaciones ambientales.http://ref.scielo.org/86hcb
Localized Faraday patterns under heterogeneous parametric excitation
Faraday waves are a classic example of a system in which an extended pattern
emerges under spatially uniform forcing. Motivated by systems in which uniform
excitation is not plausible, we study both experimentally and theoretically the
effect of heterogeneous forcing on Faraday waves. Our experiments show that
vibrations restricted to finite regions lead to the formation of localized
subharmonic wave patterns and change the onset of the instability. The
prototype model used for the theoretical calculations is the parametrically
driven and damped nonlinear Schr\"odinger equation, which is known to describe
well Faraday-instability regimes. For an energy injection with a Gaussian
spatial profile, we show that the evolution of the envelope of the wave pattern
can be reduced to a Weber-equation eigenvalue problem. Our theoretical results
provide very good predictions of our experimental observations provided that
the decay length scale of the Gaussian profile is much larger than the pattern
wavelength.Comment: 10 pages, 9 figures, Accepte
"Les rites de la Justice. Gestes et rituels judiciaires au Moyen Age" [Reseña]
Reseña de Claude Gauvard - Robert Jacob (coords.), "Les rites de la Justice. Gestes
et rituels judiciaires au Moyen Age", Paris, Le Léopard d'Or, 2000, 239 p.,
ISBN 2-86377-157-
"Delincuencia y represión en la Castilla bajomedieval (los territorios castellano-manchegos)" [Reseña]
Reseña de Juan Miguel Mendoza-Garrido, "Delincuencia y represión en la Castilla
bajomedieval (los territorios castellano-manchegos)", Granada, Grupo Editorial
Universitario, 1999, 558 p., ISBN 84-95276-30-
Jets in coronal holes: Hinode observations and 3D computer modelling
Recent observations of coronal hole areas with the XRT and EIS instruments
onboard the Hinode satellite have shown with unprecedented detail the launching
of fast, hot jets away from the solar surface. In some cases these events
coincide with episodes of flux emergence from beneath the photosphere. In this
letter we show results of a 3D numerical experiment of flux emergence from the
solar interior into a coronal hole and compare them with simultaneous XRT and
EIS observations of a jet-launching event that accompanied the appearance of a
bipolar region in MDI magnetograms. The magnetic skeleton and topology that
result in the experiment bear a strong resemblance to linear force-fee
extrapolations of the SOHO/MDI magnetograms. A thin current sheet is formed at
the boundary of the emerging plasma. A jet is launched upward along the open
reconnected field lines with values of temperature, density and velocity in
agreement with the XRT and EIS observations. Below the jet, a split-vault
structure results with two chambers: a shrinking one containing the emerged
field loops and a growing one with loops produced by the reconnection. The
ongoing reconnection leads to a horizontal drift of the vault-and-jet
structure. The timescales, velocities, and other plasma properties in the
experiment are consistent with recent statistical studies of this type of
events made with Hinode data.Comment: 10 pages, 4 figures. Revised version submitted to ApJ Letter
Magnetic evolution of superactive regions. Complexity and potentially unstable magnetic discontinuities
In this work, we have studied the temporal evolution of some properties of a
sample of superactive regions with the aim to single out the most significant
for flare activity forecasting. We have investigated properties of 14
superactive regions, observed between January 1st 2000 and December 31st 2006
with MDI/SOHO instrument and characterized by a particularly intense flare
activity during their passage on the solar disk. We have analyzed the temporal
evolution of fractal and multifractal properties of photospheric magnetic
fields, namely the generalized fractal dimension and the cntribution and
dimensionality diversities, as well as the potential unstable volumes of
magnetic discontinuities above the studied ARs. Correlations of these
quantities with the flare index, which provides information about the flare
activity of a region, have also been estimated. We found that in 50 % of our
sample the generalized fractal dimension is correlated with the flare index
computed over windows of 50 hours, while the contribution diversity and the
dimensional diversity are anticorrelated with the same index. An increase of
the potential unstable volume of magnetic discontinuities in the corona is
observed before the phases characterized by more frequent and intense flares.
We also found that the free energy distribution functions of unstable volumes
of the analyzed superactive regions can be fitted with straight lines whose
slope is larger than the values found in previous works for less active
magnetic regions. The generalized fractal dimension and the potential unstable
volume of magnetic discontinuities are the most suitable for statistical
investigations of relations with flare activity over longer (50 hours) and
shorter (few hours) time intervals, respectively
Trastornos del desarrollo en niños y adolescentes de la región de Los Ríos, Valdivia, Chile, 2006-2008
ResumenObjetivoEstudiar los posibles hallazgos de factores asociados antenatales, perinatales o posnatales, tanto de la madre como del niño, que tengan relevancia significativa en la aparición de trastornos del desarrollo.Pacientes y métodoSe creó una base de datos de todas las fichas clínicas de los pacientes con patología del desarrollo F80 a F90 CIE10 ingresados a la Unidad de Psiquiatría Infantil del Hospital Regional de Valdivia entre agosto de 2006 y diciembre de 2008. Total: 493 pacientes (48,7% del total de consultantes); grupo control de 32 niños sanos de consultorios de la ciudad. Se aplicó método estadístico odds ratio (95% confianza) para el análisis de algunas variables.ResultadosDestacan como factores de riesgo para desarrollar patología del desarrollo (p<0,005, 25% de frecuencia en población consultante): la prematurez, ser de sexo masculino, tener una madre con baja escolaridad, hospitalizaciones tempranas y enfermedades médicas antes de los 3 años (todos con odds ratio significativa). Además tener una madre psiquiátrica aumenta el doble el riesgo de desarrollar trastorno del desarrollo.ConclusiónSe requiere un trabajo colaborativo interdisciplinario entre neonatólogos, obstetras, psiquiatras infantiles y la atención primaria para detectar precozmente niños en riesgo.AbstractObjectivesTo study possible findings of factors in the antenatal, perinatal or postnatal period, in the mother or the child that may have an influence on the appearance of a developmental disorder.Patients and methodA Data Base of Clinical Histories from every patient with a developmental disorder (F80-F90 ICD10) was created. The patients attended the Child Psychiatric Unit at Hospital Regional of Valdivia, Chile, from August 2006 to December 2008. Total: 493 patientes (48.7% of the total of patients consulting); Control group: 32 healthy patients. Statistical method: odds ratio (95% confidence).ResultsThe main risk factors for developing a developmental disorder (P<.005, 25% frequency in the consulting population) are: prematurity, male sex, mother with low education, early hospitalizations, and medical illnesses (all with a significant odds ratio). Also, having a mother with psychiatric illness doubles the risk of having a developmental disorder.ConclusionIt requires an interdisciplinary collaborative work between neonatologists, obstetricians, child psychiatrists and the primary care to detect early children at risk
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