1,238 research outputs found
Geospatial distributions reflect temperatures of linguistic features.
Quantifying the speed of linguistic change is challenging because the historical evolution of languages is sparsely documented. Consequently, traditional methods rely on phylogenetic reconstruction. Here, we propose a model-based approach to the problem through the analysis of language change as a stochastic process combining vertical descent, spatial interactions, and mutations in both dimensions. A notion of linguistic temperature emerges naturally from this analysis as a dimensionless measure of the propensity of a linguistic feature to undergo change. We demonstrate how temperatures of linguistic features can be inferred from their present-day geospatial distributions, without recourse to information about their phylogenies. Thus, the evolutionary dynamics of language, operating across thousands of years, leave a measurable geospatial signature. This signature licenses inferences about the historical evolution of languages even in the absence of longitudinal data
Molecular Resolvent Operator for H2 + molecule
We present a theoretical method to extract photoelectron and nuclear kinetic energy spectra of molecules under intense ultrashort laser pulses. The method is applied to H2+ photoionization and dissociation within a 3D model of the H2+ molecule. This method is an extension to molecules of the resolvent technique originally proposed for atoms, which was recently implemented to extract absolute values of photoelectron and nuclear kinetic energy spectr
Attacks on the HF Physical Layer of Contactless and RFID Systems
International audienceno abstrac
LISA Dynamics & Control: Closed-loop Simulation and Numerical Demonstration of Time Delay Interferometry
The Laser Interferometer Space Antenna (LISA), space-based gravitational wave
observatory involves a complex multidimensional closed-loop dynamical system.
Its instrument performance is expected to be less efficiently isolated from
platform motion than was its simpler technological demonstrator, LISA
Pathfinder. It is of crucial importance to understand and model LISA dynamical
behavior accurately to understand the propagation of dynamical excitations
through the response of the instrument down to the interferometer data streams.
More generally, simulation of the system allows for the preparation of the
processing and interpretation of in-flight metrology data. In this work, we
present a comprehensive mathematical modeling of the closed-loop system
dynamics and its numerical implementation within the LISA Consortium simulation
suite. We provide, for the first time, a full time-domain numerical
demonstration of post-processing Time Delay Interferometer techniques combining
multiple position measurements with realistic control loops to create a
synthetic Michelson interferometer. We show that in the absence of physical
coupling to spacecraft and telescope motion (through tilt-to-length, stiffness
and actuation cross-talk) the effect of noisy spacecraft motion is efficiently
suppressed to a level below the noise originating in the rest of the
instrument.Comment: 26 pages, 8 figures. Revision of Subsection VII.C, and of the
physical interpretation of the comparison between Linear and Non-linear
simulations. In addition to a few editorial improvements (rephrasings, figure
and text formatting). The dynamical models, the simulations, and the results
of the article (aside from VII.C) remain unchange
Energy- and angle-resolved ionization of H2+ interacting with xuv subfemtosecond laser pulses
We present an extension of the resolvent operator method to extract fully differential ionization probabilities resulting from the interaction of ultrashort laser pulses with H2+ by including all electronic and vibrational (dissociative) degrees of freedom. The wave function from which ionization probabilities are extracted is obtained by solving the time-dependent Schrödinger equation in a grid for the case of H2+ oriented parallel to the polarization direction of the field. The performance of the method is illustrated by using pulses in the xuv domain. Correlated kinetic-energy (CKE) and correlated angular and nuclear kinetic-energy (CAKN) spectra have been evaluated and used to analyze the underlying mechanisms of the photoionization process. In particular, for pulses with a central frequency ω=0.8 a.u., which is smaller than the vertical ionization potential of H2+, we show the opening of the one-photon ionization channel by decreasing the pulse duration down to less than 1 fs. An analysis of the CKE and CAKN spectra allows us to visualize individual contributions from one- and two-photon ionization processes, as well as to study the variation of these contributions with pulse duration. The latter information is difficult to extract when only the kinetic energy release (KER) spectrum is measured. This points out the importance of performing multiple-coincidence measurements for better elucidation of competing ionization mechanisms, such as those arising when ultrashort pulses are usedWe gratefully acknowledge fruitful discussions with Dr. A. Palacios. This work was accomplished with an allocation of computer time from Mare Nostrum BSC and CCCUAM
and was partially supported by European Research Council Advanced Grant No. XCHEM 290853, MINECO Project No. FIS2013-42002-R, ERA-Chemistry Project No.
PIM2010EEC-00751, European Grant No. MC-ITN CORINF, European COST Action XLIC CM1204, and the CAM project NANOFRONTMAG. H.B. acknowledges support for mobility from ITN CORINF and is grateful for the hospitality of the Universidad Autónoma de Madrid. R.E.F.S. acknowledges FCT - Fundacao para a Ciencia e Tecnologia, Portugal, Grant No. SFRH/BD/84053/201
Stakeholder Perceptions of Point-of-Care Ultrasound Implementation in Resource-Limited Settings
Nearly half of the world lacks access to diagnostic imaging. Point of care ultrasound (POCUS) is a versatile and relatively affordable imaging modality that offers promise as a means of bridging the radiology gap and improving care in low resource settings. Methods: We performed semi-structured interviews of key stakeholders at two diverse hospitals where POCUS implementation programs had recently been conducted: one in a rural private hospital in Haiti and the other in a public referral hospital in Malawi. Questions regarding the clinical utility of POCUS, as well as barriers and facilitators of its implementation, were asked of study participants. Using the Framework Method, analysis of interview transcripts was guided by the WHO ASSURED criteria for point of care diagnostics. Results: Fifteen stakeholders with diverse roles in POCUS implementation were interviewed. Interviewees from both sites considered POCUS a valuable diagnostic tool that improved clinical decisions. They perceived barriers to adequate training as one of the most important remaining barriers to POCUS implementation. Conclusions: In spite of the increasing affordability and portability of ultrasounds devices, there are still important barriers to the implementation of POCUS in resource-limited settings
Stakeholder Perceptions of Point-of-Care Ultrasound Implementation in Resource-Limited Settings
Nearly half of the world lacks access to diagnostic imaging. Point of care ultrasound (POCUS) is a versatile and relatively affordable imaging modality that offers promise as a means of bridging the radiology gap and improving care in low resource settings. Methods: We performed semi-structured interviews of key stakeholders at two diverse hospitals where POCUS implementation programs had recently been conducted: one in a rural private hospital in Haiti and the other in a public referral hospital in Malawi. Questions regarding the clinical utility of POCUS, as well as barriers and facilitators of its implementation, were asked of study participants. Using the Framework Method, analysis of interview transcripts was guided by the WHO ASSURED criteria for point of care diagnostics. Results: Fifteen stakeholders with diverse roles in POCUS implementation were interviewed. Interviewees from both sites considered POCUS a valuable diagnostic tool that improved clinical decisions. They perceived barriers to adequate training as one of the most important remaining barriers to POCUS implementation. Conclusions: In spite of the increasing affordability and portability of ultrasounds devices, there are still important barriers to the implementation of POCUS in resource-limited settings
Estimativa de peso médio de bananas verdes comercializadas em caixas de madeira por bananicultores na região do litoral norte catarinense
Excess of weight in banana boxes is a major cause of post-harvest damages. The aim of the present study was to estimate the average weight of unripe banana from the Cavendish Subgroup [Musa spp. (AAA)] in wooden boxes in packing houses, considering a maximum sampling error of 5%. The banana boxes were weighed just prior to delivery, without the previous knowledge of people involved in the packing, in 28 packing houses located in the main banana producing area on the northern coast of the state of Santa Catarina, Brazil. The mean average net weight of the boxes in the packing houses was23.01kg, which is 9.6% above the reference weight (21kg). This implies that there is an excess of weight in the boxes, which may decrease the fruit quality, as well as the data of banana producton and of the farmer’s income. It can be concluded that there is a need for beter regulatory business laws regarding the banana market and commitment of those involved in post--harvestng practces of the productve chains.A carga que resulta em excesso de peso em caixas de bananas é uma das principais causas de danos pós-colheita. Este trabalho teve como objetivo estmar o peso líquido médio de bananas verdes do subgrupo Cavendish [Musa spp. (AAA)] em caixas de madeira, em casas de embalagem de produtores, considerando um erro máximo de amostragem de 5%. As caixas de bananas, prontas para expedição, foram pesadas sem conhecimento prévio dos embaladores, em 28 casas de embalagemno litoral norte catarinense. O valor estimado do peso líquido médio dessas caixas nas casas de embalagem foi de 23,01kg, valor 9,6% acima do peso de referência comercial, que é 21kg. Evidenciou-se o excesso de peso nas caixas, o que compromete a qualidade dos frutos e os dados estatisticos e econômicos de produção. Concluiu-se que há necessidade de aprimoramentos na regulamentação da comercialização de bananas verdes e no grau de corresponsabilidade dos integrantes da cadeia produtiva da banana quanto às prátcas em pós-colheita
- …