859 research outputs found
Application of semidefinite programming to maximize the spectral gap produced by node removal
The smallest positive eigenvalue of the Laplacian of a network is called the
spectral gap and characterizes various dynamics on networks. We propose
mathematical programming methods to maximize the spectral gap of a given
network by removing a fixed number of nodes. We formulate relaxed versions of
the original problem using semidefinite programming and apply them to example
networks.Comment: 1 figure. Short paper presented in CompleNet, Berlin, March 13-15
(2013
REPORT OF THE 2019 ICCAT WORKSHOP ON SWORDFISH BIOLOGY STUDIES FOR GROWTH, REPRODUCTION AND GENETICS
This report describes the June, 2019 ICCAT workshop on swordfish biology studies for growth,
reproduction and genetics, hosted by the Instituto Português do Mar e da Atmosfera, Olhão,
Portugal . The major objectives of the workshop were to 1) refine sampling and biological data
collection protocols, 2) develop protocols and start the sample processing and analysis, and 3)
plan for the project future steps. The biological sampling program was established by ICCAT’s
Swordfish Species Group in 2018, aiming to improve knowledge of the stock distribution, age and
gender of the catch, growth rate, age at maturation, maturation rate, spawning season and
location and diet. This work will contribute to the next major advance in the assessment of
swordfish status, by permitting the development of more spatially and biologically realistic
population models used in both Atlantic and Mediterranean populations assessments and within
the ICCAT Management Strategy Evaluation (MSE) for North Atlantic swordfish.En prens
Distributed information consensus filters for simultaneous input and state estimation
This paper describes the distributed information filtering where a set of sensor networks are required to simultaneously estimate input and state of a linear discrete-time system from collaborative manner. Our research purpose is to develop a consensus strategy in which sensor nodes communicate within the network through a sequence of Kalman iterations and data diffusion. A novel recursive information filtering is proposed by integrating input estimation error into measurement data and weighted information matrices. On the fusing process, local system state filtering transmits estimation information using the consensus averaging algorithm, which penalizes the disagreement in a dynamic manner. A simulation example is provided to compare the performance of the distributed information filtering with optimal Gillijins–De Moor’s algorithm
Distributed Adaptive Attitude Synchronization of Multiple Spacecraft
This paper addresses the distributed attitude synchronization problem of
multiple spacecraft with unknown inertia matrices. Two distributed adaptive
controllers are proposed for the cases with and without a virtual leader to
which a time-varying reference attitude is assigned. The first controller
achieves attitude synchronization for a group of spacecraft with a leaderless
communication topology having a directed spanning tree. The second controller
guarantees that all spacecraft track the reference attitude if the virtual
leader has a directed path to all other spacecraft. Simulation examples are
presented to illustrate the effectiveness of the results.Comment: 13 pages, 11 figures. To appear in SCIENCE CHINA Technological
Science
Epidemiology and natural history of central venous access device use and infusion pump function in the NO16966 trial
Background: Central venous access devices in fluoropyrimidine therapy are associated with complications; however, reliable data are lacking regarding their natural history, associated complications and infusion pump performance in patients with metastatic colorectal cancer.<p></p>
Methods: We assessed device placement, use during treatment, associated clinical outcomes and infusion pump perfomance in the NO16966 trial.<p></p>
Results: Device replacement was more common with FOLFOX-4 (5-fluorouracil (5-FU)+oxaliplatin) than XELOX (capecitabine+oxaliplatin) (14.1% vs 5.1%). Baseline device-associated events and post-baseline removal-/placement-related events occurred more frequently with FOLFOX-4 than XELOX (11.5% vs 2.4% and 8.5% vs 2.1%). Pump malfunctions, primarily infusion accelerations in 16% of patients, occurred within 1.6–4.3% of cycles. Fluoropyrimidine-associated grade 3/4 toxicity was increased in FOLFOX-4-treated patients experiencing a malfunction compared with those who did not (97 out of 155 vs 452 out of 825 patients), predominantly with increased grade 3/4 neutropenia (53.5% vs 39.8%). Febrile neutropenia rates were comparable between patient cohorts±malfunction. Efficacy outcomes were similar in patient cohorts±malfunction.<p></p>
Conclusions: Central venous access device removal or replacement was common and more frequent in patients receiving FOLFOX-4. Pump malfunctions were also common and were associated with increased rates of grade 3/4 haematological adverse events. Oral fluoropyrimidine-based regimens may be preferable to infusional 5-FU based on these findings
Quantum computation based on d-level cluster states
The concept of qudit (a d-level system) cluster state is proposed by
generalizing the qubit cluster state (Phys. Rev. Lett. \textbf{86}, 910 (2001))
according to the finite dimensional representations of quantum plane algebra.
We demonstrate their quantum correlations and prove a theorem which guarantees
the availability of the qudit cluster states in quantum computation. We
explicitly construct the network to show the universality of the one-way
computer based on the defined qudit cluster states and single-qudit
measurement. And the corresponding protocol of implementing one-way quantum
computer can be suggested with the high dimensional "Ising" model which can be
found in many magnetic systems.Comment: Revtex4, 15 pages, 3 eps figure
From fidelity to entanglement of entropy of the one-dimensional transverse-field quantum compass model
We study fidelity and fidelity susceptibility by addition of entanglement of
entropy in the one-dimensional quantum compass model in a transverse magnetic
field numerically. The whole four recognized gapped regions in the ground state
phase diagram are in the range of our investigation. Power-law divergence at
criticality accompanied by finite size scaling indicates the field induced
quantum phase transitions are of second order as well as from the scaling
behavior of the extremum of fidelity susceptibility is shown the quantum
critical exponents are different in the various regions of phase diagram. We
further calculate a recently proposed quantum information theoretic measure,
von-Neumann entropy, and show that this measure provide appropriate signatures
of the quantum phase transitions (QPT)s occurring at the critical fields.
Von-Neumann entropy indicates a measure of entanglement between some-particle
block and the rest of the system. We show the value of entanglement between a
two-particle block with the rest of the system is more dependent on the power
of exchange couplings connecting the block with the rest of the system than the
power of exchange coupling between two particles in the block
Light induced self-written waveguides interactions in photopolymer media
We present experimental and theoretical study of the interaction of Light Induced Self-Written (LISW) waveguides in photopolymers. We show that the diffusion of the monomer controls the refractive index distribution. Consequently it influences the interaction between the LISW channels allowing the observation of anti-crossing behavior or the propagation of an array of non interacting LISW waveguides
Intravenous glutamine decreases lung and distal organ injury in an experimental model of abdominal sepsis
Introduction The protective effect of glutamine, as a pharmacological agent against lung injury, has been reported in experimental sepsis; however, its efficacy at improving oxygenation and lung mechanics, attenuating diaphragm and distal organ injury has to be better elucidated. In the present study, we tested the hypothesis that a single early intravenous dose of glutamine was associated not only with the improvement of lung morpho-function, but also the reduction of the inflammatory process and epithelial cell apoptosis in kidney, liver, and intestine villi. Methods Seventy-two Wistar rats were randomly assigned into four groups. Sepsis was induced by cecal ligation and puncture surgery (CLP), while a sham operated group was used as control (C). One hour after surgery, C and CLP groups were further randomized into subgroups receiving intravenous saline (1 ml, SAL) or glutamine (0.75 g/kg, Gln). At 48 hours, animals were anesthetized, and the following parameters were measured: arterial oxygenation, pulmonary mechanics, and diaphragm, lung, kidney, liver, and small intestine villi histology. At 18 and 48 hours, Cytokine-Induced Neutrophil Chemoattractant (CINC)-1, interleukin (IL)-6 and 10 were quantified in bronchoalveolar and peritoneal lavage fluids (BALF and PLF, respectively). Results CLP induced: a) deterioration of lung mechanics and gas exchange; b) ultrastructural changes of lung parenchyma and diaphragm; and c) lung and distal organ epithelial cell apoptosis. Glutamine improved survival rate, oxygenation and lung mechanics, minimized pulmonary and diaphragmatic changes, attenuating lung and distal organ epithelial cell apoptosis. Glutamine increased IL-10 in peritoneal lavage fluid at 18 hours and bronchoalveolar lavage fluid at 48 hours, but decreased CINC-1 and IL-6 in BALF and PLF only at 18 hours. Conclusions In an experimental model of abdominal sepsis, a single intravenous dose of glutamine administered after sepsis induction may modulate the inflammatory process reducing not only the risk of lung injury, but also distal organ impairment. These results suggest that intravenous glutamine may be a potentially beneficial therapy for abdominal sepsis.Centres of Excellence Program (PRONEX-FAPERJ)Brazilian Council for Scientific and Technological Development (CNPq)Carlos Chagas FilhoRio de Janeiro State Research Supporting Foundation (FAPERJ)Sao Paulo State Research Supporting Foundation (FAPESP
Genotoksičnost metalnih nanočestica: osvrt na podatke istraživanja In vivo
With increasing production and application of a variety of nanomaterials (NMs), research on their cytotoxic and genotoxic potential grows, as the exposure to these nano-sized materials may potentially result in adverse health effects. In large part, indications for potential DNA damaging effects of nanoparticles (NPs) originate from inconsistent in vitro studies. To clarify these effects, the implementation of in vivo studies has been emphasised. This paper summarises study results of genotoxic effects of NPs, which are available in the recent literature. They provide indications that some NP types cause both DNA strand breaks and chromosomal damages in experimental animals. Their genotoxic effects, however, do not depend only on particle size, surface modifi cation (particle coating), and exposure route, but also on exposure duration. Currently available animal studies may suggest differing mechanisms (depending on the duration of exposure) by which living organisms react to NP contact. Nevertheless, due to considerable inconsistencies in the recent literature and the lack of standardised test methods - a reliable hazard assessment of NMs is still limited. Therefore, international organisations (e.g. NIOSH) suggest utmost caution when potential exposure of humans to NMs occurs, as long as evidence of their toxicological and genotoxic effect(s) is limited.S povećanjem proizvodnje i primjene niza različitih nanomaterijala (NM) raste i potreba istraživanja njihovih mogućih citotoksičnih i genotoksičnih učinaka kao i drugih štetnih učinaka na zdravlje u uvjetima profesionalne ili opće izloženost ljudi. Indikacije potencijanog oštećenja DNA kojeg uzrokuju nanočestice u velikoj mjeri proizlaze iz nedosljednih in vitro ispitivanja. Kako bi se razjasnili ti učinci, naglašena je potreba provedbe in vivo ispitivanja. Ovaj pregledni rad sažima rezultate procjene genotoksičnih učinaka nanočestica koji su objavljeni u novijoj stručnoj i znanstvenoj literaturi. Navedeni rezultati pokazuju da određene nanočestice uzrokuju lomove u molekuli DNA i oštećuju kromosome u eksperimentalnim životinjama. Njihovi genotoksični učinci ne ovise samo o veličini čestice, modifi kaciji površine (oblaganje čestice) i načinu izlaganja, već i o trajanju izloženosti nanočesticama. Postojeća istraživanja provedena na životinjama upućuju na različite mehanizme koji ovise o trajanju izlaganja i pomoću kojih živi organizmi reagiraju na doticaj s nanočesticama. Međutim postoje brojne nedosljednosti u novijoj literaturi, a standardne testne metode nisu dostupne pa je stoga pouzdanija procjena opasnosti od izlaganja nanomaterijalima u ljudi još uvijek veoma ograničena. Stoga se u međunarodnim dokumentima savjetuje oprez prilikom svakog izlaganja ljudi nanomaterijalima kako bi se spriječili mogući opći toksični genotoksični učinci
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