13,654 research outputs found
A long-range and long-life telemetry data-acquisition system for heart rate and multiple body temperatures from free-ranging animals
The system includes an implantable transmitter, external receiver-retransmitter collar, and a microprocessor-controlled demodulator. The size of the implant is suitable for animals with body weights of a few kilograms or more; further size reduction of the implant is possible. The ECG is sensed by electrodes designed for internal telemetry and to reduce movement artifacts. The R-wave characteristics are then specifically selected to trigger a short radio frequency pulse. Temperatures are sensed at desired locations by thermistors and then, based on a heartbeat counter, transmitted intermittently via pulse interval modulation. This modulation scheme includes first and last calibration intervals for a reference by ratios with the temperature intervals to achieve good accuracy even over long periods. Pulse duration and pulse sequencing are used to discriminate between heart rate and temperature pulses as well as RF interference
Avaliação de linhagens, materiais comerciais e duas populações de milho para tolerância a alumÃnio.
Neste trabalho realizou-se a avaliacao da tolerancia a Al (4,5 mg.l) de 39 linhagens, 98 materiais comerciais, 167 progenies de uma populacao IAC-Maya e de 466 progenies de uma populacao IAC-Genetica, usando-se a tecnica de solucao nutritiva. Foram usadas na avaliacao as caracterÃsticas ICR (indice de crescimento da radicula = comprimento relativo da radicula -CRR (CR+Al.CR-Al)- multiplicado por comprimento relativo da raiz secundaria mais longa - CRRSML (CRSML+Al/CRSML-Al) e CLR (comprimento liquido da radicula = diferenca entre os valores de comprimento da radicula - CR - obtidos no inicio e fim do periodo de crescimento das plantas em presenca de Al). As linhagens e as progenies da populacao IAC-Maya a de milho foram avaliadas através do ICR enquanto que os materiais comerciais e as progenies da populacao IAC-Genetica foram avaliados pelos valores de CLR. Os controles utilizados foram IAC HS1227 (tolerante a Al) e IAC HS7777 (sensivel a Al). O metodo de solucao nutritiva foi eficiente na diferenciacao da tolerancia a Al dentre os materiais testados, evidenciando a ocorrencia de ampla variabilidade genetica para essa caracteristica. As seguintes linhagens e materiais comerciais apresentaram tolerancia a Al (4,5 mg/l): Porto Rico 70. D,2, IP 38-5-3, IP 365-4-I, IA 2992-3-1-2-3, Vic 3-2-3-30-V-6, 490, 519, 532, 536-2 e 820 (linhagens) e AG 82, AG 260, AGROMEM 1022, ASGROW 1255, DINA 03S, DINA 47, IAC Hmd 7974, SS 1243 e UNICAMP 720 (materiais comerciais)
Revisiting fundamental welding concepts to improve additive manufacturing: From theory to practice
The authors acknowledge Fundacao para a Ciencia e Tecnologia (FCT) for its financial support through the project UID/EMS/00667/2019. Fundo Regional para a Ciencia e Tecnologia and Projeto de I&DT for companies in copromotion SLM-XL, (Ref 3346), funded by Fundo Europeu de Desenvolvimento Regional (FEDER) through Programa Operacional Regional de Lisboa.Additive manufacturing technologies based on melting and solidification have considerable similarities with fusion-based welding technologies, either by electric arc or high-power beams. However, several concepts are being introduced in additive manufacturing which have been extensively used in multipass arc welding with filler material. Therefore, clarification of fundamental definitions is important to establish a common background between welding and additive manufacturing research communities. This paper aims to review these concepts, highlighting the distinctive characteristics of fusion welding that can be embraced by additive manufacturing, namely the nature of rapid thermal cycles associated to small size and localized heat sources, the non-equilibrium nature of rapid solidification and its effects on: internal defects formation, phase transformations, residual stresses and distortions. Concerning process optimization, distinct criteria are proposed based on geometric, energetic and thermal considerations, allowing to determine an upper bound limit for the optimum hatch distance during additive manufacturing. Finally, a unified equation to compute the energy density is proposed. This equation enables to compare works performed with distinct equipment and experimental conditions, covering the major process parameters: power, travel speed, heat source dimension, hatch distance, deposited layer thickness and material grain size.publishersversionpublishe
Influence of spin fluctuations near the Mott transition: a DMFT study
Dynamics of magnetic moments near the Mott metal-insulator transition is
investigated by a combined slave-rotor and Dynamical Mean-Field Theory solution
of the Hubbard model with additional fully-frustrated random Heisenberg
couplings. In the paramagnetic Mott state, the spinon decomposition allows to
generate a Sachdev-Ye spin liquid in place of the collection of independent
local moments that typically occurs in the absence of magnetic correlations.
Cooling down into the spin-liquid phase, the onset of deviations from pure
Curie behavior in the spin susceptibility is found to be correlated to the
temperature scale at which the Mott transition lines experience a marked
bending. We also demonstrate a weakening of the effective exchange energy upon
approaching the Mott boundary from the Heisenberg limit, due to quantum
fluctuations associated to zero and doubly occupied sites.Comment: 6 pages, 3 figures. V3 was largely expande
Removal of vegetation in the state of Mato Grosso: a perspective based on the actions of IBAMA between 1998 and 2016
The State of Mato Grosso in the Midwest region of Brazil has, in recent decades, become the main area of agricultural production in the country. By positioning itself as the new agricultural frontier, the state has instigated a constant conflict between agriculture and environmental protection. In this context, this study briefly discusses and analyzes deforestation in the region based on data on sanctions issued by the Instituto Brasileiro do Meio Ambiente e dos Recursos Naturais Renováveis (Brazilian Institute for the Environment and Renewable Natural Resources; IBAMA), the Brazilian environmental regulatory and inspection agency, between 1998 and 2016. Annual vegetation removal reached its highest values in 2003 and 2004 (1,109 km2) and then decreased from 2005 to 2008 (4,353 km2) before stabilizing at the lowest level between 2009 and 2016 (1,138 km2)
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Double Chain Ladder and Bornhuetter-Ferguson
In this article we propose a method close to Double Chain Ladder (DCL) introduced by MartÃnez-Miranda, Nielsen, and Verrall (2012a). The proposed method is motivated by the potential lack of stability of the DCL method (and of the classical Chain ladder method [CLM] itself). We consider the implicit estimation of the underwriting year inflation in the CLM method and the explicit estimation of it in DCL. This may represent a weak point for DCL and CLM because the underwriting year inflation might be estimated with significant uncertainty. A key feature of the new method is that the underwriting year inflation can be estimated from the less volatile incurred data and then transferred into the DCL model. We include an empirical illustration that illustrates the differences between the estimates of the IBNR and RBNS cash flows from DCL and the new method. We also apply bootstrap estimation to approximate the predictive distributions
Pd/Cu Site Interchange and Non-Fermi-Liquid Behavior in UCu_4Pd
X-ray-absorption fine-structure measurements of the local structure in
UCu_4Pd are described which indicate a probable lattice-disorder origin for
non-Fermi-liquid behavior in this material. Short Pd-Cu distances are observed,
consistent with 24 +/- 3% of the Pd atoms occupying nominally Cu sites. A
"Kondo disorder" model, based on the effect on the local Kondo temperature T_K
of this interchange and some additional bond-length disorder, agrees
quantitatively with previous experimental susceptibility data, and therefore
also with specific heat and magnetic resonance experiments.Comment: 4 pages, 3 PostScript figures, to be published in PR
Wormhole Cosmic Censorship
We analyze the properties of a Kerr-like wormhole supported by phantom
matter, which is an exact solution of the Einstein-phantom field equations. It
is shown that the solution has a naked ring singularity which is unreachable to
null geodesics falling freely from the outside. Similarly to Roger Penrose's
cosmic censorship, that states that all naked singularities in the Universe
must be protected by event horizons, here we conjecture from our results that a
naked singularity can also be fully protected by the intrinsic properties of a
wormhole's throat
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Validating the double chain ladder stochastic claims reserving model
Double chain ladder, introduced by MartÃnez-Miranda et al. (2012), is a statistical model to predict outstanding claim reserve. Double chain ladder and Bornhuetter-Ferguson are extensions of the originally described double chain ladder model which gain more stability through including expert knowledge via an incurred claim amounts triangle. In this paper, we introduce a third method, the incurred double chain ladder, which replicates the popular results from the classical chain ladder on incurred data. We will compare and validate these three using two data sets from major property and casualty insurers
Diversity of fungal endophytic community in Quercus suber L. under different climate scenarios
Cork oak (Quercus suber L.) is an evergreen oak tree species, typically found throughout the Mediterranean Basin that presents a great ecological and economic importance in Portugal. The ecological importance is due to the role in the protection of the soil, biodiversity control, water quality and oxygen production. The cork production and processing confer cork oak a great economic relevance in Portugal. An increase of cork oak decline due to biotic and abiotic stresses has been reported, which could damage the ecosystem and lower cork production. Fungal species as D;plod;a corticola and Biscogniauxia mediterranea are cork oak pathogens that cause tree decline and affect cork productivity. The incidence of both diseases seems to increase when trees are under several environmental stresses, such as increased temperatures or drought. In this work, fungal endophytic species of cork oak were collected in different sites of Portugal (Bragança, Gerês, Alcobaça, Grândola e Gavião). The collection sites displayed differences in water availability and cork oak trees in different phytosanitary conditions. The community of fungal endophytes of young twigs and one/two-years old branches were studied by detecting fungal outgrowing from aseptic plant pieces and grouping them into morphotypes. A differentiation between live and death (xylem) branch tissue was considered by culturing the most superficial branch wood or the most inner wood. Collection sites with higher precipitation seem to display a more diverse community. Branches displayed a more diverse fungal community than young twigs, being the endophytic community, present in inner wood, more similar between sites, than young twigs or outer branch tissues. This study allowed the comparison of fungal endophytic communities living in cork oak trees with different water availability levels and disease symptoms. The results provide a good starting point towards the comprehension of the fungal community influence in disease occurrence.info:eu-repo/semantics/publishedVersio
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