18,834 research outputs found
Perspectivas para o marco legal do terceiro setor
A existência de um ambiente regulatório moderno, claro e estável é fator fundamental para promover a expansão e a qualificação do investimento social privado no Brasil. Com base nessa premissa, o GIFE -- Grupo de Institutos, Fundações e Empresas desenvolve, desde 2003, ações com o objetivo de contribuir para o aperfeiçoamento da legislação brasileira do terceiro setor, construindo um ambiente mais favorável ao investimento social e à atuação das organizações da sociedade civil. Essa publicação tem como objetivo orientar a atuação de advocacy do GIFE
IN-SITU XRD STUDIES OF THERMAL STABILITY OF PURE SILICA AND Ti-MCM-41 MATERIALS
In this work we present a study on the thermal stability of siliceous and titanium containing ordered mesoporous materials with MCM-41 structure, prepared by direct synthesis at ambient temperature and pressure, as previously described [1]. Grades with different pore diameter and Si/Ti molar ratios were analyzed, in the form of compacted powder, to assess its influence on the order-disorder transition temperature
LISA Sensitivities to Gravitational Waves from Relativistic Metric Theories of Gravity
The direct observation of gravitational waves will provide a unique tool for
probing the dynamical properties of highly compact astrophysical objects,
mapping ultra-relativistic regions of space-time, and testing Einstein's
general theory of relativity. LISA (Laser Interferometer Space Antenna), a
joint NASA-ESA mission to be launched in the next decade, will perform these
scientific tasks by detecting and studying low-frequency cosmic gravitational
waves through their influence on the phases of six modulated laser beams
exchanged between three remote spacecraft. By directly measuring the
polarization components of the waves LISA will detect, we will be able to test
Einstein's theory of relativity with good sensitivity. Since a gravitational
wave signal predicted by the most general relativistic metric theory of gravity
accounts for {\it six} polarization modes (the usual two Einstein's tensor
polarizations as well as two vector and two scalar wave components), we have
derived the LISA Time-Delay Interferometric responses and estimated their
sensitivities to vector- and scalar-type waves. We find that (i) at frequencies
larger than roughly the inverse of the one-way light time ( Hz.) LISA is more than ten times sensitive to scalar-longitudinal and
vector signals than to tensor and scalar-transverse waves, and (ii) in the low
part of its frequency band is equally sensitive to tensor and vector waves and
somewhat less sensitive to scalar signals.Comment: Paper submitted to Physical Review D. It is 20 pages long and
contains 14 figure
Real-time communications over wired/wireless PROFIBUS networks supporting inter-cell mobility
PROFIBUS is an international standard (IEC 61158, EN 50170) for factory-floor communications, with several thousands
of installations worldwide. Taking into account the increasing need for mobile devices in industrial environments,
one obvious solution is to extend traditional wired PROFIBUS networks with wireless capabilities. In this paper, we outline
the major aspects of a hybrid wired/wireless PROFIBUS-based architecture, where most of the design options were
made in order to guarantee the real-time behaviour of the overall network. We also introduce the timing unpredictability
problems resulting from the co-existence of heterogeneous physical media in the same network. However, the major focus
of this paper is on how to guarantee real-time communications in such a hybrid network, where nodes (and whole segments)
can move between different radio cells (inter-cell mobility). Assuming a simple mobility management mechanism
based on mobile nodes performing periodic radio channel assessment and switching, we propose a methodology to compute
values for specific parameters that enable an optimal (minimum) and bounded duration of the handoff procedure
Genome-wide transcriptomics analysis identifies sox7 and sox18 as specifically regulated by gata4 in cardiomyogenesis
This work was supported by British Heart Foundation (BHF Project Grant no PG/13/23/30080 to B.A.A and S.H.), Biotechnology and Biological Sciences Research Council (BB/M001695/1 to S.H.) and the University of Aberdeen (for A.T.L). Acknowledgements We’re grateful to Ms Yvonne Turnbull and Ms Kate Watt for technical assistance and lab management. We would like to thank Professor Cedric Blanpain and Dr Xionghui Li from Université Libre de Bruxelles for providing training of ES cell manipulation and Mesp1/Gata4 cell lines. We are grateful to Professor Todd Evans from Weill Cornell Medical College for generously providing iGata ES cell lines. We also would like to thank Professor Aaron Zorn and Scott Rankin for providing Xsox18 plasmid.Peer reviewedPublisher PD
Toxicidade aguda (CL50) do permanganato de potássio em juvenis de robalo peva (Centropomus parallelus).
TCC (graduação) - Universidade Federal de Santa Catarina, Centro de Ciências Agrárias, Curso de Engenharia de Aquicultura.O robalo peva, Centropomus parallelus, é um peixe marinho eurihalino com potencial para aquicultura devido a seu alto valor e aceitação no mercado com uma carne com pouca gordura. Com a intensificação dos cultivos há o surgimento de doenças que necessitam de tratamentos químicos eficientes sem prejudicar a espécie cultivada. O objetivo deste trabalho foi a avaliação da toxicidade aguda (CL50;96 h) do permanganato de potássio em juvenis de robalo peva com 2,22±0,38 cm e 6,15±0,39 g expostos as concentrações de 0,50; 0,75; 1,00; 1,25; 1,50 e 1,75 mg.L-1 de KMnO4. Nas concentrações de 0,50; 0,75 e 1,00 mg.L-1 não houve mortalidade, já nas concentrações de 1,25; 1,50 e 1,75 houve mortalidade. Na concentração mais alta (1,75 mg.L-1) a mais letal, onde após 4:30 horas de exposição ao permanganato foi encontrado o primeiro peixe morto. O baixo valor de CL50;96 h (1,12 mg.L-1) sugere que esta espécie de peixe no tamanho testado, apresenta sensibilidade ao composto
Energy and delay trade-off of the GTS allocation mechanism in IEEE 802.15.4 for wireless sensor networks
The IEEE 802.15.4 protocol proposes a flexible communication solution for Low-Rate Wireless Personal
Area Networks (LR-WPAN) including wireless sensor networks (WSNs). It presents the advantage to fit
different requirements of potential applications by adequately setting its parameters. When in beaconenabled
mode, the protocol can provide timeliness guarantees by using its Guaranteed Time Slot (GTS)
mechanism. However, power-efficiency and timeliness guarantees are often two antagonistic requirements in
wireless sensor networks. The purpose of this paper is to analyze and propose a methodology for setting the
relevant parameters of IEEE 802.15.4-compliant WSNs that takes into account a proper trade-off between
power-efficiency and delay bound guarantees. First, we propose two accurate models of service curves for a
GTS allocation as a function of the IEEE 802.15.4 parameters, using Network Calculus formalism. We then
evaluate the delay bound guaranteed by a GTS allocation and express it as a function of the duty cycle. Based
on the relation between the delay requirement and the duty cycle, we propose a power-efficient superframe
selection method that simultaneously reduces power consumption and enables meeting the delay
requirements of real-time flows allocating GTSs. The results of this work may pave the way for a powerefficient
management of the GTS mechanism in an IEEE 802.15.4 cluster
IEEE 802.15.4: a Federating Communication Protocol for Time-Sensitive Wireless Sensor Networks
Wireless Sensor Networks (WSNs) have been attracting increasing interests for developing a new
generation of embedded systems with great potential for many applications such as surveillance,
environment monitoring, emergency medical response and home automation. However, the
communication paradigms in WSNs differ from the ones attributed to traditional wireless networks,
triggering the need for new communication protocols. In this context, the recently standardised IEEE
802.15.4 protocol presents some potentially interesting features for deployment in wireless sensor
network applications, such as power-efficiency, timeliness guarantees and scalability. Nevertheless,
when addressing WSN applications with (soft/hard) timing requirements some inherent paradoxes
emerge, such as power-efficiency versus timeliness, triggering the need of engineering solutions for an
efficient deployment of IEEE 802.15.4 in WSNs. In this technical report, we will explore the most
relevant characteristics of the IEEE 802.15.4 protocol for wireless sensor networks and present the
most important challenges regarding time-sensitive WSN applications. We also provide some timing
performance and analysis of the IEEE 802.15.4 that unveil some directions for resolving the
previously mentioned paradoxes
Pulsar Timing Sensitivities to Gravitational Waves from Relativistic Metric Theories of Gravity
Pulsar timing experiments aimed at the detection of gravitational radiation
have been performed for decades now. With the forthcoming construction of large
arrays capable of tracking multiple millisecond pulsars, it is very likely we
will be able to make the first detection of gravitational radiation in the
nano-Hertz band, and test Einstein's theory of relativity by measuring the
polarization components of the detected signals. Since a gravitational wave
predicted by the most general relativistic metric theory of gravity accounts
for {\it six} polarization modes (the usual two Einstein's tensor polarizations
as well as two vector and two scalar wave components), we have estimated the
single-antenna sensitivities to these six polarizations. We find pulsar timing
experiments to be significantly more sensitive, over their entire observational
frequency band ( Hz), to scalar-longitudinal and
vector waves than to scalar-transverse and tensor waves. At Hz and
with pulsars at a distance of kpc, for instance, we estimate an average
sensitivity to scalar-longitudinal waves that is more than two orders of
magnitude better than the sensitivity to tensor waves. Our results imply that a
direct detection of gravitational radiation by pulsar timing will result into a
test of the theory of general relativity that is more stringent than that based
on monitoring the decay of the orbital period of a binary system.Comment: 11 pages, 2 figures. Submitted to Phys. Rev.
IEEE 802.15.4 for wireless sensor networks: a technical overview
Low-rate low-power consumption and low-cost
communication are the key points that lead to the specification of
the IEEE 802.15.4 standard. This paper overviews the technical
features of the physical layer and the medium access control sublayer
mechanisms of the IEEE 802.15.4 protocol that are most
relevant for wireless sensor network applications. We also
discuss the ability of IEEE 802.15.4 to fulfil the requirements of
wireless sensor network applications
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