553 research outputs found
Avaliação do tratamento cirúrgico da úlcera péptica perfurada.
Trabalho de Conclusão de Curso - Universidade Federal de Santa Catarina, Centro de Ciências da Saúde, Departamento de Clínica Cirúrgica, Curso de Medicina, Florianópolis, 199
Extremal Problems on the Hypercube
PhDThe hypercube, Qd, is a natural and much studied combinatorial object, and we discuss
various extremal problems related to it.
A subgraph of the hypercube is said to be (Qd; F)-saturated if it contains no copies of
F, but adding any edge forms a copy of F. We write sat(Qd; F) for the saturation number,
that is, the least number of edges a (Qd; F)-saturated graph may have. We prove the
upper bound sat(Qd;Q2) < 10 2d, which strongly disproves a conjecture of Santolupo that
sat(Qd;Q2) =
�� 1 4 + o(1)
d2d��1. We also prove upper bounds on sat(Qd;Qm) for general
m.Given a down-set A and an up-set B in the hypercube, Bollobás and Leader conjectured
a lower bound on the number of edge-disjoint paths between A and B in the directed
hypercube. Using an unusual form of the compression argument, we confirm the conjecture
by reducing the problem to a the case of the undirected hypercube. We also prove an
analogous conjecture for vertex-disjoint paths using the same techniques, and extend both
results to the grid.
Additionally, we deal with subcube intersection graphs, answering a question of Johnson
and Markström of the least r = r(n) for which all graphs on n vertices may be represented as
subcube intersection graph where each subcube has dimension exactly r. We also contribute
to the related area of biclique covers and partitions, and study relationships between various
parameters linked to such covers and partitions.
Finally, we study topological properties of uniformly random simplicial complexes, employing
a characterisation due to Korshunov of almost all down-sets in the hypercube as a
key tool
Theoretical analysis of multimodal four-wave mixing in optical microwires
Optical fiber microwires (OFMs) are nonlinear optical waveguides that support several spatial modes. The multimodal generalized nonlinear Schrodinger equation (MM-GNLSE) is deduced taking into account the linear and nonlinear modal coupling. A detailed theoretical description of four-wave mixing (FWM) considering the modal coupling is developed. Both, the intramode and the intermode phase-matching conditions is calculated for an optical microwire in a strong guiding regime. Finally, the FWM dynamics is studied and the amplitude evolution of the pump beams, the signal and the idler are analyzed
Energy Consumption and Latency Analysis for Wireless Multimedia Sensor Networks
Energy and bandwidth are limited resources in wireless sensor networks, and communication consumes significant amount of energy. When wireless vision sensors are used to capture and transfer image and video data, the problems of limited energy and bandwidth become even more pronounced. Thus, message traffic should be decreased to reduce the communication cost. In many applications, the interest is to detect composite and semantically higher-level events based on information from multiple sensors. Rather than sending all the information to the sinks and performing composite event detection at the sinks or control-center, it is much more efficient to push the detection of semantically high-level events within the network, and perform composite event detection in a peer-to-peer and energy-efficient manner across embedded smart cameras. In this paper, three different operation scenarios are analyzed for a wireless vision sensor network. A detailed quantitative comparison of these operation scenarios are presented in terms of energy consumption and latency. This quantitative analysis provides the motivation for, and emphasizes (1) the importance of performing high-level local processing and decision making at the embedded sensor level and (2) need for peer-to-peer communication solutions for wireless multimedia sensor networks
The Hubble Rate Trouble: An Effective Field Theory of Dark Matter
The Hubble constant inferred from the 6-parameter fit to the CMB power
spectrum conflicts with the value obtained from direct measurements via type Ia
supernova and Cepheids observations. We write down effective operators
involving spin-0, spin-1/2, and spin-1 dark matter that lead to the
relativistic production of dark matter particles at early times, and
consequently lead to an increase in the number of relativistic degrees of
freedom. This mechanism which is amenable to CMB, BBN, and structure formation
observables can sufficiently raise the value of the Hubble constant derived
from CMB and reconcile local and CMB probes of the Hubble constant. This
mechanism alone increases up to , and with
the help of a Phantom-like cosmology, reach . Lastly, we outline the region of parameter space which reproduces
while obeying all relevant
constraints.Comment: 10 pages and 14 figure
Adaptive path planning for fusing rapidly exploring random trees and deep reinforcement learning in an agriculture dynamic environment UAVs
Unmanned aerial vehicles (UAV) are a suitable solution for monitoring growing cultures due to the possibility of covering a large area and the necessity of periodic monitoring. In inspection and monitoring tasks, the UAV must find an optimal or near-optimal collision-free route given initial and target positions. In this sense, path-planning strategies are crucial, especially online path planning that can represent the robot’s operational environment or for control purposes. Therefore, this paper proposes an online adaptive path-planning solution based on the fusion of rapidly exploring random trees (RRT) and deep reinforcement learning (DRL) algorithms applied to the generation and control of the UAV autonomous trajectory during an olive-growing fly traps inspection task. The main objective of this proposal is to provide a reliable route for the UAV to reach the inspection points in the tree space to capture an image of the trap autonomously, avoiding possible obstacles present in the environment. The proposed framework was tested in a simulated environment using Gazebo and ROS. The results showed that the proposed solution accomplished the trial for environments up to 300 m3 and with 10 dynamic objects.The authors would like to thank the following Brazilian Agencies CEFET-RJ, CAPES, CNPq, and FAPERJ. The authors also want to thank the Research Centre in Digitalization and Intelligent Robotics (CeDRI), Instituto Politécnico de Bragança–IPB (UIDB/05757/2020 and UIDP/05757/2020), the Foundation for Science and Technology (FCT, Portugal) for financial support through national funds FCT/MCTES (PIDDAC) to CeDRI, and Laboratório Associado para a Sustentabilidade e Tecnologia em Regiões de Montanha (SusTEC) and IPB, Portugal. This work was carried out under the Project “OleaChain: Competências para a sustentabilidade e inovação da cadeia de valor do olival tradicional no Norte Interior de Portugal” (NORTE-06-3559-FSE-000188), an operation to hire highly qualified human resources, funded by NORTE 2020 through the European Social Fund (ESF).info:eu-repo/semantics/publishedVersio
Elaboración de bioplásticos a base de almidón de semilla (Persea americana) y pectina de cáscara de (Citrus limon)
El amplio consumo de productos plásticos sintéticos implica la búsqueda de
nuevas alternativas sustentables que los reemplacen. Por lo tanto, esta
investigación tiene como objetivo elaborar bioplástico a partir de almidón de
semilla de Persea americana con pectina de cáscara de Citrus limon. Para la
obtención del almidón se realizaron procesos de remojo de semilla,
sedimentación, secado, pulverizado y tamizado. Para la obtención de
pectina se realizó el proceso de hidrólisis ácida, agitación-calentamiento,
enfriamiento, secado y homogenización. El almidón y la pectina presentaron
granulometría de 425 um, pH ácido, humedades de 20.6 y 35.2 %
respectivamente. Los mejores resultados se obtuvieron con el bioplástico de
dosis 3 (15g de almidón de semilla de Persea americana con 17g pectina de
cáscara de Citrus limon), alcanzando fuerza de tracción de 4.46 kg/cm2,
elongación de 7.79% y biodegradabilidad de 31.35 % en tres semanas
sumergido el bioplástico en agua de mar. En conclusión, el almidón extraído
de las semillas de Persea americana y pectina de cáscaras de Citrus limon,
fueron componentes esenciales para la elaboración de bioplásticos
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