4,786 research outputs found
Effective lagrangian for a mass dimension one fermionic field in curved spacetime
In this work we use momentum-space techniques to evaluate the propagator
for a spin mass dimension one spinor field on a curved
Friedmann-Robertson-Walker spacetime. As a consequence, we built the one-loop
correction to the effective lagrangian in the coincidence limit. Going further
we compute the effective lagrangian in the finite temperature regime. We arrive
at interesting cosmological consequences, as time-dependent cosmological
`constant', fully explaining the functional form of previous cosmological
models.Comment: 9 pages, 0 figure
Efeitos de Anestésico Local no Tempo Entre Bólus e na Duração do Trabalho de Parto em Patient-Controlled Epidural Analgesia: Estudo Prospectivo de Dois Regimes de Doses Ultra-Baixas com Ropivacaina e Sufentanil
BACKGROUND: Patient-controlled epidural analgesia with low concentrations of anesthetics is effective in reducing labor pain. The aim of this study was to assess and compare two ultra-low dose regimens of ropivacaine and sufentanil (0.1% ropivacaine plus 0.5 μg.ml-1 sufentanil vs. 0.06% ropivacaine plus 0.5 μg.ml-1 sufentanil) on the intervals between boluses and the duration of labor.
MATERIAL AND METHODS:
In this non-randomized prospective study, conducted between January and July 2010, two groups of parturients received patient-controlled epidural analgesia: Group I (n = 58; 1 mg.ml-1 ropivacaine + 0.5 μg.ml-1 sufentanil) and Group II (n = 57; 0.6 mg.ml-1 ropivacaine + 0.5 μg.ml-1 sufentanil). Rescue doses of ropivacaine at the concentration of the assigned group without sufentanil were administered as necessary. Pain, local anesthetic requirements, neuraxial blockade characteristics, labor and neonatal outcomes, and maternal satisfaction were recorded.
RESULTS:
The ropivacaine dose was greater in Group I (9.5 [7.7-12.7] mg.h-1 vs. 6.1 [5.1-9.8 mg.h-1], p < 0.001). A time increase between each bolus was observed in Group I (beta = 32.61 min, 95% CI [25.39; 39.82], p < 0.001), whereas a time decrease was observed in Group II (beta = -1.40 min, 95% CI [-2.44; -0.36], p = 0.009). The duration of the second stage of labor in Group I was significantly longer than that in Group II (78 min vs. 65 min, p < 0.001).
CONCLUSIONS:
Parturients receiving 0.06% ropivacaine exhibited less evidence of cumulative effects and exhibited faster second stage progression than those who received 0.1% ropivacaine
A Piezoelectric Device for Measurement and Power Harvesting Applications
Com o apoio RAADRI.With the fast growth of wireless communications between nodes/sensor units, devices installed in remote places require power energy supply solutions to assure their functionally and data communication capabilities. For these applications energy harvesting takes place as a good solution, to increase the availability of energy, in opposition to the conventional systems of energy supply. Regenerative energy sources like thermoelectric, magnetic, piezoelectric, and/or renewable sources such as photovoltaic, wind, among others, allowed the development of different powering solutions for sensor units. The purpose of this work is to characterize a piezoelectric device to measure and capture mechanical vibrations from equipments, structures and piping vibrations, as well as from other sources. The study is carried out taking into account the power supply capabilities of piezoelectric devices as a function of the amplitude and frequency of the vibration stimulus, as well as, the electrical characteristics of the load circuit
Study of latencies in ThingSpeak
IoT platforms play an important role on modern measurement systems because they allow the ingestion and processing of huge amounts of data (big data). Given the increasing use of these platforms, it is important to characterize their performance and robustness in real application scenarios. The paper analyzes the ThingSpeak platform by measuring the latencies associated to data packets sent to cloud and replied back, and by checking the consistency of the returned data. Several experiments were done considering different ways to access the platform: REST API, MQTT API, and MQTT broker alone. For each experiment, the methodology is explained, results are presented, and conclusions are extracted. The REST and MQTT APIs have similar performances, with roundtrip times between 1 s and 3 s. The MQTT broker alone is more agile, with roundtrip times below 250 ms. In all cases, the up and down links are far from being symmetric, with the uplink delay showing higher variance than the downlink delay. The obtained results can serve as a reference for other IoT platforms and provide guidelines for application development.info:eu-repo/semantics/publishedVersio
Infill masonry: simple analytical methods for seismic design
The latest earthquake codes in Europe require the safety assessment of no-structural elements (parapets, masonry wall’s veneer, infill walls, etc.), as their collapse entails risks for people or for the main structure stability. This work made possible th e development of a design method, supported by previous experimental researches by applying cyclic out-of-plane loads to damaged masonry infill in RC frames. Panels tested reproduce Portuguese traditional RC structure construction system and two reinforced solutions were created as innovative solutions. The experimental campaign was carried out in order to determine: masonry properties; out-of-plane panel behaviour with previous in-plane damage; building behaviour subjected to dynamic tests
performed in shaking table. Using finite element method to reproduce experimental tests and to broaden the range of samples it was possible to figure out equations according to parametric analysis which was able to reproduce in-plane and out-plane behaviour leading to an estimated load bearing capacity of each model and to determine frame strength and its stiffness. Those equations permit to design or verify the masonry infill panels in RC frames subjected to seismic loads
Aplicação fracionada de nitrogênio no algodoeiro irrigado.
bitstream/CNPA/18339/1/BOLETIM72.pd
Behavior of masonry infill panels in RC frames subjected to in plane and out of plane loads
The building envelope in Europe is usually made of masonry walls, with enclosure and infill
functions. Masonry walls have a major economical importance and contribute significantly to
the building performance. Even if infill walls have no load-bearing function, they contribute
significantly to the seismic behavior of buildings. Therefore, their adequate structural
performance is needed, avoiding the occurrence of severe in-plane damage, with very large
economical losses, and the out-of-plane expulsion, which additionally represents a large risk
for human life.
Recent earthquake codes in Europe require the safety assessment of non-structural elements
(parapets, veneer masonry walls, infill walls, etc.), when their collapse entails risks for people
or for the main structure. The Eurocode standards, entering the mandatory stage now,
incorporate new requirements to be fulfilled by buildings or their parts. Such is the case of
masonry infilled RC frames whose panels, according to Eurocode 8, are explicitly required to
withstand the out-of-plane movement induced by earthquakes. Appropriate measures should
be taken to avoid brittle failure and premature disintegration of the infill walls, as well as the
partial or total out-of-plane collapse of slender masonry panels.
This paper presents the experimental work and results achieved by applying cyclic out-ofplane
loads to damaged masonry infilled RC frames. The masonry panels were previously
damaged by applying an in-plane cyclic load after which the cyclic out-of- plane loads were
applied. The frames and panels tested follow the traditional Portuguese RC structure
construction system to which different types of reinforcement have been introduced in the
panels
Serious game for physical rehabilitation: measuring the effectiveness of virtual and real training environments
Recent advances in low-cost natural user interfaces such as Microsoft Kinect and Leap Motion controller allow the Virtual Reality implementation of 3D serious games for, posture, upper limb and lower limb rehabilitation purposes. However, it is very important to compare the results obtained by the users that train in virtual and real environments. This paper presents a virtual reality serious game for upper limb rehabilitation using a natural user interface expressed by Leap Motion controller. One of the developed virtual reality serious game for rehabilitation is converted to a real scenario with the same elements and rules and the same aims of physical rehabilitation. In order to extract appropriate information from the serious game based on real objects a RFID technology was used together with software components developed in LabVIEW. The evaluation of hand muscles' activity during the training session is based on the usage of thermography that permits to measure in an unobtrusive way the distribution of the temperature on the hands' level. Based on analysis of thermographic images obtained before and after serious game practice, the level of activity of specific muscles associated with training for virtual and real scenario is extracted. Experimental results that are also included in the paper underline the effectiveness of the proposed method for the comparison of the training in virtual and real scenarios.info:eu-repo/semantics/acceptedVersio
Resistência de acessos do banco ativo de germoplasma de mandioca à broca das hastes Coelosternus granicollis (Pierce, 1916) (Coleoptera: Curculionidae).
Dentre os insetos que se alimentam da planta da mandioca, destaca-se a broca das hastes, Coelosternus sp., que pode provocar inclusive a morte das plantas de variedades suscetÃveis à infestação.bitstream/CPAA-2009-09/9290/1/IT_7_99.pd
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