503 research outputs found
Distribution of the S-matrix in chaotic microwave cavities with direct processes and absorption
We quantify the presence of direct processes in the S-matrix of chaotic
microwave cavities with absorption in the one-channel case. To this end the
full distribution P_S(S) of the S-matrix, i.e. S=\sqrt{R}e^{i\theta}, is
studied in cavities with time-reversal symmetry for different antenna coupling
strengths T_a or direct processes. The experimental results are compared with
random-matrix calculations and with numerical simulations based on the
Heidelberg approach including absorption. The theoretical result is a
generalization of the Poisson kernel. The experimental and the numerical
distributions are in excellent agreement with random-matrix predictions for all
cases.Comment: 4 pages, 4 figure
DCMF: DC & Microformats, a good marriage
This report introduces the Dublin Core Microformats (DCMF) project, a new way to use the DC element set within X/HTML. The DC microformats encode explicit semantic expressions in an X/HTML webpage, by using a specific list of terms for values of the attributes “rev” and “rel” for and elements, and “class” and “id” of other elements. Microformats can be easily processed by user agents and software, enabling a high level of interoperability. These characteristics are crucial for the growing number of social applications allowing users to participate in the Web 2.0 environment as information creators and consumers. This report reviews the origins of microformats; illustrates the coding of DC microformats using the Dublin Core Metadata Gen tool, and a Firefox extension for extraction and visualization; and discusses the benefits of creating Web services utilizing DC microformats
Trusted Computing using Enhanced Manycore Architectures with Cryptoprocessors
International audienceManycore architectures correspond to a main evolution of computing systems due to their high processing power. Many applications can be executed in parallel which provides users with a very efficient technology. Cloud computing is one of the many domains where manycore architectures will play a major role. Thus, building secure manycore architectures is a critical issue. However a trusted platform based on manycore architectures is not available yet. In this paper we discuss the main challenges and some possible solutions to enhance manycore architectures with cryptoprocessor
Applications of Direct Injection Soft Chemical Ionisation-Mass Spectrometry for the Detection of Pre-blast Smokeless Powder Organic Additives
Analysis of smokeless powders is of interest from forensics and security perspectives. This article reports the detection of smokeless powder organic additives (in their pre-detonation condition), namely the stabiliser diphenylamine and its derivatives 2-nitrodiphenylamine and 4-nitrodiphenylamine, and the additives (used both as stabilisers and plasticisers) methyl centralite and ethyl centralite, by means of swab sampling followed by thermal desorption and direct injection soft chemical ionisation-mass spectrometry. Investigations on the product ions resulting from the reactions of the reagent ions H3O+ and O2+ with additives as a function of reduced electric field are reported. The method was comprehensively evaluated in terms of linearity, sensitivity and precision. For H3O+, the limits of detection (LoD) are in the range of 41-88 pg of additive, for which the accuracy varied between 1.5 and 3.2%, precision varied between 3.7 and 7.3% and linearity showed R20.9991. For O2+, LoD are in the range of 72 to 1.4 ng, with an accuracy of between 2.8 and 4.9% and a precision between 4.5 and 8.6% and R20.9914. The validated methodology was applied to the analysis of commercial pre-blast gun powders from different manufacturers.(VLID)4826148Accepted versio
Carbon dioxide emissions from semi-arid soils amended with biochar alone or combined with mineral and organic fertilizers
Semi-arid soils cover a significant area of Earth s land surface and typically contain large amounts of inorganic C. Determining the effects of biochar additions on CO2 emissions fromsemi-arid soils is therefore essential for evaluating the potential of biochar as a climate change mitigation strategy. Here, we measured the CO2 that evolved from semi-arid calcareous soils amended with biochar at rates of 0 and 20 t ha?1 in a full factorial combination with three different fertilizers (mineral fertilizer, municipal solid waste compost, and sewage sludge) applied at four rates (equivalent to 0, 75, 150, and 225 kg potentially available N ha?1) during 182 days of aerobic incubation. A double exponential model, which describes cumulative CO2 emissions from two active soil C compartments with different turnover rates (one relatively stable and the other more labile), was found to fit verywell all the experimental datasets. In general, the organic fertilizers increased the size and decomposition rate of the stable and labile soil C pools. In contrast, biochar addition had no effects on any of the double exponential model parameters and did not interact with the effects ascribed to the type and rate of fertilizer. After 182 days of incubation, soil organic and microbial biomass C contents tended to increase with increasing the application rates of organic fertilizer, especially of compost, whereas increasing the rate of mineral fertilizer tended to suppress microbial biomass. Biochar was found to increase both organic and inorganic C contents in soil and not to interactwith the effects of type and rate of fertilizer on C fractions. As a whole, our results suggest that the use of biochar as enhancer of semi-arid soils, either alone or combined with mineral and organic fertilizers, is unlikely to increase abiotic and biotic soil CO2 emissions
Case series of gallstone ileus: only enterolitotomy, one stage or two stage surgery?
Biliary ileus is a rare disease and an infrequent cause of intestinal obstruction, occasionally occurs in frail elderly patients and has a certain predilection for the female sex. The diagnosis is complex and requires a high clinical suspicion and complementary examinations such as abdominal radiography and contrasted abdominal tomography. Treatment should be individualized according to the clinical characteristics of each patient, with the alternatives being resolution only by enterolithotomy, one stage surgery and two stage surgery. We report 3 cases of biliary ileus, each one managed with a different surgical procedure. The decision was aimed at resolving the intestinal obstruction by enterolithotomy, and the definitive management was performed according to the clinical characteristics of each patient; however, there is no consensus or algorithm that recommends the ideal surgical technique. The recommended surgical procedure for the resolution of biliary ileus will be discussed
The Evolution of the Kinematics of Nebular Shells in Planetary Nebulae in the Milky Way Bulge
We study the line widths in the [\ion{O}{3}]5007 and H lines
for two groups of planetary nebulae in the Milky Way bulge based upon
spectroscopy obtained at the Observatorio Astron\'omico Nacional in the Sierra
San Pedro M\'artir (OAN-SPM) using the Manchester Echelle Spectrograph. The
first sample includes objects early in their evolution, having high H
luminosities, but [\ion{O}{3}]. The second
sample comprises objects late in their evolution, with \ion{He}{2} . These planetary nebulae represent evolutionary
phases preceeding and following those of the objects studied by Richer et al.
(2008). Our sample of planetary nebulae with weak [\ion{O}{3}]5007 has
a line width distribution similar to that of the expansion velocities of the
envelopes of AGB stars, and shifted to systematically lower values as compared
to the less evolved objects studied by Richer et al. (2008). The sample with
strong \ion{He}{2} has a line width distribution
indistinguishable from that of the more evolved objects from Richer et al.
(2008), but a distribution in angular size that is systematically larger and so
they are clearly more evolved. These data and those of Richer et al. (2008)
form a homogeneous sample from a single Galactic population of planetary
nebulae, from the earliest evolutionary stages until the cessation of nuclear
burning in the central star. They confirm the long-standing predictions of
hydrodynamical models of planetary nebulae, where the kinematics of the nebular
shell are driven by the evolution of the central star.Comment: accepted for publication in the Astrophysical Journa
Diagnóstico de producción en ganado lechero en pastoreo de un grupo ganadero de validación y transferencia de tecnología
The regionalization of framing issues for producers Livestock Group of Validation and Technology Transfer (GGAVATT) from San Jose Miahuatlán Veracruz, Mexico, under the current production of native grass prairie with mainly during the months of higher temperature have a poor performance and thus milk production declines which promotes a great use of concentrated feeds which causes an increase in production cost and less use to them. For this purpose we made a diagnosis of current conditions GGAVATT production, yielding information that helps us source and compared to determine precisely what the effect of applying the proposed alternative. We propose an alternative implementation of pastures with improved pastures needed to produce a greater amount of forage per unit area especially in the colder months.La regionalización de la problemática encuadrando a los productores del Grupo Ganadero de Validación y Transferencia de Tecnología (GGAVATT) de San José Miahuatlán Veracruz, México, bajo la actual situación de producción de praderas básicamente con gramas nativas que durante los meses de menor frío tienen un pobre desempeño y por ende la producción de leche se deteriora lo cual promueve una gran utilización de alimentos concentrados lo que provoca un incremento en el costo de producción y una menor utilidad para estos. Para dicho propósito se realizó un diagnóstico de las condiciones actuales de producción del GGAVATT, arrojando información que nos sirve de partida y de comparación para determinar con precisión cuál es el efecto de aplicar la alternativa propuesta. Se plantea como alternativa la implantación de praderas con pastos mejorados que permitan producir una mayor cantidad de forrajes por unidad de superficie sobre todo en los meses de menor temperatura
Empty Urbanism: the bursting of the Spanish housing bubble
The depth of the Spanish housing crisis manifests itself in the collapse of construction activity and in the amount of housing and land stocks. The geography of the crisis shows its widespread nature, and the intensity of the previous bubble explains spatial differences. Resulting from this collapse are some problematic areas of 'empty urbanism'. An enormous land bubble, emerging from the peculiar Spanish urban development model, was a key factor in the impacts - caused by the crisis - on the territory and land-use plans. The crisis has demonstrated the unsustainability of this and the urgency of change in the existing land-use plans
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