Continuous Forest Fire Propagation in a Local Small World Network Model

This paper presents the development of a new continuous forest fire model implemented as a weighted local small-world network approach. This new approach was designed to simulate fire patterns in real, heterogeneous landscapes. The wildland fire spread is simulated on a square lattice in which each cell represents an area of the land's surface. The interaction between burning and non-burning cells, in the present work induced by flame radiation, may be extended well beyond nearest neighbors. It depends on local conditions of topography and vegetation types. An approach based on a solid flame model is used to predict the radiative heat flux from the flame generated by the burning of each site towards its neighbors. The weighting procedure takes into account the self-degradation of the tree and the ignition processes of a combustible cell through time. The model is tested on a field presenting a range of slopes and with data collected from a real wildfire scenario. The critical behavior of the spreading process is investigated

Why Ni3_3Al is an itinerant ferromagnet but Ni3_3Ga is not

Ni$_3$Al and Ni$_3$Ga are closely related materials on opposite sides of a ferromagnetic quantum critical point. The Stoner factor of Ni is virtually the same in both compounds and the density of states is larger in Ni$_3$Ga. So, according to the Stoner theory, it should be more magnetic, and, in LDA calculations, it is. However, experimentally, it is a paramagnet, while Ni$_3$Al is an itinerant ferromagnet. We show that the critical spin fluctuations are stronger than in Ni$_3$Ga, due to a weaker q-dependence of the susceptibility, and this effect is strong enough to reverse the trend. The approach combines LDA calculations with the Landau theory and the fluctuation-dissipation theorem using the same momentum cut-off for both materials. The calculations provide evidence for strong, beyond LDA, spin fluctuations associated with the critical point in both materials, but stronger in Ni$_3$Ga than in Ni$_3$Al.Comment: replaced (incorrect version submitted

Overestimation of Vitamin a Supplementation Coverage from District Tally Sheets Demonstrates Importance of Population-Based Surveys for Program Improvement: Lessons from Tanzania.

Tanzania has conducted a national twice-yearly Vitamin A supplementation (VAS) campaign since 2001. Administrative coverage rates based on tally sheets consistently report >90% coverage; however the accuracy of these rates are uncertain due to potential errors in tally sheets and their aggregation, incomplete or inaccurate reporting from distribution sites, and underestimating the target population. The post event coverage survey in Mainland Tanzania sought to validate tally-sheet based national coverage estimates of VAS and deworming for the June 2010 mass distribution round, and to characterize children missed by the national campaign. WHO/EPI randomized cross-sectional cluster sampling methodology was adapted for this study, using 30 clusters by 40 individuals (n = 1200), in addition to key informant interviews. Households with children 6-59 months of age were included in the study (12-59 months for deworming analysis). Chi-squared tests and logistic regression analysis were used to test differences between children reached and not reached by VAS. Data was collected within six weeks of the June 2010 round. A total of 1203 children, 58 health workers, 30 village leaders and 45 community health workers were sampled. Preschool VAS coverage was 65% (95% CI: 62.7-68.1), approximately 30% lower than tally-sheet coverage estimates. Factors associated with not receiving VAS were urban residence [OR = 3.31; p = 0.01], caretakers who did not hear about the campaign [OR = 48.7; p<0.001], and Muslim households [OR<3.25; p<0.01]. There were no significant differences in VAS coverage by child sex or age, or maternal age or education. Coverage estimation for vitamin A supplementation programs is one of most powerful indicators of program success. National VAS coverage based on a tally-sheet system overestimated VAS coverage by ∼30%. There is a need for representative population-based coverage surveys to complement and validate tally-sheet estimates

Traumatic brain injury: Failure of the intravenous route for the administration of bone marrow stromal stem cells as treatment of chronic neurological sequels

Objetivo: Estudiar el posible efecto terapéutico de la administración intravenosa de células madre estromales (CME) obtenidas de médula ósea para tratar las secuelas neurológicas en fase crónica tras una lesión cerebral traumática. Material y método: Se realizó un modelo de lesión cerebral traumática en ratas Wistar adultas y se estudió el déficit neurológico inducido en el curso de los dos meses siguientes, por medio del test mNSS y el test Smart. Tras ese tiempo, en fase de secuelas crónicamente establecidas, se administraron intravenosamente 15 x 106 CME (n:10) o suero fisiológico (n:10). En los dos meses siguientes se estudió la posible modificación de las secuelas neurológicas. Resultados: Cuando se compararon los resultados de la valoración funcional entre ambos grupos experimentales, no se observaron diferencias estadísticamente significativas. Conclusión: Nuestros resultados sugieren que el trasplante de CME por vía intravenosa, en una fase de secuelas crónicamente establecidas tras una lesión traumática cerebral grave, no tiene efecto terapéuticoObjective: We studied the possible therapeutic effect of intravenous administration (noninvasive method) of BMSCs to treat neurological sequels in a chronic stage after TBI. Material and method: A model of TBI in adult Wistar rats was performed and we studied the neurological deficit induced in the course of two months, through the mNSS and Smart tests. After this time, with established sequels, 15 x 106 BMSCs (n = 10) or saline (n = 10) were administered intravenously. Changes in the neurological deficits were studied in two months. Results: Comparison of functional changes between both experimental groups showed no statistically significant differences. Conclusions: Our results suggest that transplantation of BMSCs intravenously, at a stage of established sequels after severe TBI, has no therapeutic effectEsta investigación ha sido financiada por FUNDACIÓN MAPFR

The MGDO software library for data analysis in Ge neutrinoless double-beta decay experiments

The GERDA and Majorana experiments will search for neutrinoless double-beta decay of germanium-76 using isotopically enriched high-purity germanium detectors. Although the experiments differ in conceptual design, they share many aspects in common, and in particular will employ similar data analysis techniques. The collaborations are jointly developing a C++ software library, MGDO, which contains a set of data objects and interfaces to encapsulate, store and manage physical quantities of interest, such as waveforms and high-purity germanium detector geometries. These data objects define a common format for persistent data, whether it is generated by Monte Carlo simulations or an experimental apparatus, to reduce code duplication and to ease the exchange of information between detector systems. MGDO also includes general-purpose analysis tools that can be used for the processing of measured or simulated digital signals. The MGDO design is based on the Object-Oriented programming paradigm and is very flexible, allowing for easy extension and customization of the components. The tools provided by the MGDO libraries are used by both GERDA and Majorana.Comment: 4 pages, 1 figure, proceedings for TAUP201

BLITZ: Wireless Link Quality Estimation in the Dark

Abstract. We present BLITZ, a novel link quality estimator that relies on physical-layer synchronization errors to estimate the expected packet delivery ratio of wireless links. In contrast to all existing link quality estimators which estimate the packet delivery based on statistics from packets that are successfully decoded, our technique works even when packets at the receiver are not correctly received, i.e., when the synchronization fails. The core idea of BLITZ is to exploit informa-tion from chip errors in the received preamble of any transmitted direct sequence spread spectrum signals such as IEEE 802.15.4. Using extensive measurements over cable, wireless static and wireless mobile scenarios, we show that our pro-posed estimator outperforms existing estimators in terms of both accuracy and speed. Across diverse environmental conditions and the full range of possible link qualities, BLITZ provides packet delivery ratio estimates with an absolute error below six percent within just a few milliseconds.

Effects of Al doping on the structural and electronic properties of Mg(1-x)Al(x)B2

We have studied the structural and electronic properties of Mg(1-x)Al(x)B2 within the Virtual Crystal Approximation (VCA) by means of first-principles total-energy calculations. Results for the lattice parameters, the electronic band structure, and the Fermi surface as a function of Al doping for 0<x<0.6 are presented. The ab initio VCA calculations are in excellent agreement with the experimentally observed change in the lattice parameters of Al doped MgB2. The calculations show that the Fermi surface associated with holes a the boron planes collapses gradually with aluminum doping and vanishes for x=0.56. In addition, an abrupt topological change in the sigma-band Fermi surface was found for x=0.3. The calculated hole density correlates closely with existing experimental data for Tc(x), indicating that the observed loss of superconductivity in Mg(1-x)Al(x)B2 is a result of hole bands filling.Comment: 4 pages (revtex) and 4 figures (postscript

The AMS-02 RICH Imager Prototype - In-Beam Tests with 20 GeV/c per Nucleon Ions -

A prototype of the AMS Cherenkov imager (RICH) has been tested at CERN by means of a low intensity 20 GeV/c per nucleon ion beam obtained by fragmentation of a primary beam of Pb ions. Data have been collected with a single beam setting, over the range of nuclear charges 2<Z<~45 in various beam conditions and using different radiators. The charge Z and velocity beta resolutions have been measured.Comment: 4 pages, contribution to the ICRC 200

Tracking azimuthons in nonlocal nonlinear media

We study the formation of azimuthons, i.e., rotating spatial solitons, in media with nonlocal focusing nonlinearity. We show that whole families of these solutions can be found by considering internal modes of classical non-rotating stationary solutions, namely vortex solitons. This offers an exhaustive method to identify azimuthons in a given nonlocal medium. We demonstrate formation of azimuthons of different vorticities and explain their properties by considering the strongly nonlocal limit of accessible solitons.Comment: 11 pages, 7 figure