6,455 research outputs found
Efficient construction of maximally localized photonic Wannier functions: locality criterion and initial conditions
Wannier function expansions are well suited for the description of photonic-
crystal-based defect structures, but constructing maximally localized Wannier
functions by optimizing the phase degree of freedom of the Bloch modes is
crucial for the efficiency of the approach. We systematically analyze different
locality criteria for maximally localized Wannier functions in two- dimensional
square and triangular lattice photonic crystals, employing (local)
conjugate-gradient as well as (global) genetic-algorithm-based, stochastic
methods. Besides the commonly used second moment (SM) locality measure, we
introduce a new locality measure, namely the integrated modulus (IM) of the
Wannier function. We show numerically that, in contrast to the SM criterion,
the IM criterion leads to an optimization problem with a single extremum, thus
allowing for fast and efficient construction of maximally localized Wannier
functions using local optimization techniques. We also present an analytical
formula for the initial choice of Bloch phases, which under certain conditions
represents the global maximum of the IM criterion and, thus, further increases
the optimization efficiency in the general case
Quantum Renormalization Group for 1 Dimensional Fermion Systems
Inspired by the superblock method of White, we introduce a simple
modification of the standard Renormalization Group (RG) technique for the study
of quantum lattice systems. Our method which takes into account the effect of
Boundary Conditions(BC), may be regarded as a simple way for obtaining first
estimates of many properties of quantum lattice systems. By applying this
method to the 1-dimensional free and interacting fermion system, we obtain the
ground state energy with much higher accuracy than the standard RG. We also
calculate the density-density correlation function in the free-fermion case
which shows good agreement with the exact result.Comment: LaTex file, 1 PS figur
A statistical MMN reflects the magnitude of transitional probabilities in auditory sequences
Within the framework of statistical learning, many behavioural studies
investigated the processing of unpredicted events. However, surprisingly few
neurophysiological studies are available on this topic, and no statistical
learning experiment has investigated electroencephalographic (EEG) correlates
of processing events with different transition probabilities. We carried out
an EEG study with a novel variant of the established statistical learning
paradigm. Timbres were presented in isochronous sequences of triplets. The
first two sounds of all triplets were equiprobable, while the third sound
occurred with either low (10%), intermediate (30%), or high (60%) probability.
Thus, the occurrence probability of the third item of each triplet (given the
first two items) was varied. Compared to high-probability triplet endings,
endings with low and intermediate probability elicited an early anterior
negativity that had an onset around 100 ms and was maximal at around 180 ms.
This effect was larger for events with low than for events with intermediate
probability. Our results reveal that, when predictions are based on
statistical learning, events that do not match a prediction evoke an early
anterior negativity, with the amplitude of this mismatch response being
inversely related to the probability of such events. Thus, we report a
statistical mismatch negativity (sMMN) that reflects statistical learning of
transitional probability distributions that go beyond auditory sensory memory
capabilities
Flavour Changing Neutral Currents, Weak-Scale Scalars and Rare Top Decays
We examine the decays  and  in the Standard
Model with an extra scalar doublet and no discrete symmetry preventing
tree-level flavour changing neutral currents. The Yukawa couplings of the new
scalars are assumed to be proportional to fermion masses, evading bounds on
FCNC's from the light quark sector. These rare top decays may be visible at the
SSC.Comment: (some wording changed, and several references added) 13 pages, 2
  figures included, uses harvmac.tex and epsf.tex, UCSD/PTH 93-0
Austria. Report on the drug situation 2006.
Commissioned each year by the EMCCDA and produced by the national focal points of the Reitox network, the National reports draw an overall picture of the drug phenomenon at national level in each EU Member State. These data are key information to the EMCCDA and are an important resource, among others, for the compilation of its Annual repor
The use of urinary proteomics in the assessment of suitability of mouse models for ageing
Ageing is a complex process characterised by a systemic and progressive deterioration of biological functions. As ageing is associated with an increased prevalence of age-related chronic disorders, understanding its underlying molecular mechanisms can pave the way for therapeutic interventions and managing complications. Animal models such as mice are commonly used in ageing research as they have a shorter lifespan in comparison to humans and are also genetically close to humans. To assess the translatability of mouse ageing to human ageing, the urinary proteome in 89 wild-type (C57BL/6) mice aged between 8–96 weeks was investigated using capillary electrophoresis coupled to mass spectrometry (CE-MS). Using age as a continuous variable, 295 peptides significantly correlated with age in mice were identified. To investigate the relevance of using mouse models in human ageing studies, a comparison was performed with a previous correlation analysis using 1227 healthy subjects. In mice and humans, a decrease in urinary excretion of fibrillar collagens and an increase of uromodulin fragments was observed with advanced age. Of the 295 peptides correlating with age, 49 had a strong homology to the respective human age-related peptides. These ortholog peptides including several collagen (N = 44) and uromodulin (N = 5) fragments were used to generate an ageing classifier that was able to discriminate the age among both wild-type mice and healthy subjects. Additionally, the ageing classifier depicted that telomerase knock-out mice were older than their chronological age. Hence, with a focus on ortholog urinary peptides mouse ageing can be translated to human ageing
Distributed state estimation for uncertain Markov-type sensor networks with mode-dependent distributed delays
This the post-print version of the Article. The official published version can be accessed from the link below - Copyright @ 2012 John Wiley & Sons, Ltd.In this paper, the distributed state estimation problem is investigated for a class of sensor networks described by uncertain discrete-time dynamical systems with Markovian jumping parameters and distributed time-delays. The sensor network consists of sensor nodes characterized by a directed graph with a nonnegative adjacency matrix that specifies the interconnection topology (or the distribution in the space) of the network. Both the parameters of the target plant and the sensor measurements are subject to the switches from one mode to another at different times according to a Markov chain. The parameter uncertainties are norm-bounded that enter into both the plant system as well as the network outputs. Furthermore, the distributed time-delays are considered, which are also dependent on the Markovian jumping mode. Through the measurements from a small fraction of the sensors, this paper aims to design state estimators that allow the nodes of the sensor network to track the states of the plant in a distributed way. It is verified that such state estimators do exist if a set of matrix inequalities is solvable. A numerical example is provided to demonstrate the effectiveness of the designed distributed state estimators.This work was supported in part by the Royal Society of the U.K., the National Natural Science Foundation of China under Grants 60804028 and 61028008, the Specialized Research Fund for the Doctoral Program of Higher Education for New Teachers in China under Grant 200802861044, the Teaching and Research Fund for Excellent Young Teachers at Southeast University of China, the International Science and Technology Cooperation Project of China under Grant No. 2009DFA32050, and the Alexander von Humboldt Foundation of Germany
Effect of Trans-Nasal Evaporative Intra-arrest Cooling on Functional Neurologic Outcome in Out-of-Hospital Cardiac Arrest : The PRINCESS Randomized Clinical Trial
© 2019 American Medical Association. All rights reserved.Importance: Therapeutic hypothermia may increase survival with good neurologic outcome after cardiac arrest. Trans-nasal evaporative cooling is a method used to induce cooling, primarily of the brain, during cardiopulmonary resuscitation (ie, intra-arrest). Objective: To determine whether prehospital trans-nasal evaporative intra-arrest cooling improves survival with good neurologic outcome compared with cooling initiated after hospital arrival. Design, Setting, and Participants: The PRINCESS trial was an investigator-initiated, randomized, clinical, international multicenter study with blinded assessment of the outcome, performed by emergency medical services in 7 European countries from July 2010 to January 2018, with final follow-up on April 29, 2018. In total, 677 patients with bystander-witnessed out-of-hospital cardiac arrest were enrolled. Interventions: Patients were randomly assigned to receive trans-nasal evaporative intra-arrest cooling (n = 343) or standard care (n = 334). Patients admitted to the hospital in both groups received systemic therapeutic hypothermia at 32°C to 34°C for 24 hours. Main Outcomes and Measures: The primary outcome was survival with good neurologic outcome, defined as Cerebral Performance Category (CPC) 1-2, at 90 days. Secondary outcomes were survival at 90 days and time to reach core body temperature less than 34°C. Results: Among the 677 randomized patients (median age, 65 years; 172 [25%] women), 671 completed the trial. Median time to core temperature less than 34°C was 105 minutes in the intervention group vs 182 minutes in the control group (P < .001). The number of patients with CPC 1-2 at 90 days was 56 of 337 (16.6%) in the intervention cooling group vs 45 of 334 (13.5%) in the control group (difference, 3.1% [95% CI, -2.3% to 8.5%]; relative risk [RR], 1.23 [95% CI, 0.86-1.72]; P = .25). In the intervention group, 60 of 337 patients (17.8%) were alive at 90 days vs 52 of 334 (15.6%) in the control group (difference, 2.2% [95% CI, -3.4% to 7.9%]; RR, 1.14 [95% CI, 0.81-1.57]; P = .44). Minor nosebleed was the most common device-related adverse event, reported in 45 of 337 patients (13%) in the intervention group. The adverse event rate within 7 days was similar between groups. Conclusions and Relevance: Among patients with out-of-hospital cardiac arrest, trans-nasal evaporative intra-arrest cooling compared with usual care did not result in a statistically significant improvement in survival with good neurologic outcome at 90 days. Trial Registration: ClinicalTrials.gov Identifier: NCT01400373.Peer reviewedFinal Accepted Versio
Conservation of core complex subunits shaped the structure and function of photosystem I in the secondary endosymbiont alga Nannochloropsis gaditana
Photosystem I (PSI) is a pigment protein complex catalyzing the light-driven electron transport from plastocyanin to ferredoxin in oxygenic photosynthetic organisms. Several PSI subunits are highly conserved in cyanobacteria, algae and plants, whereas others are distributed differentially in the various organisms. Here we characterized the structural and functional properties of PSI purified from the heterokont alga Nannochloropsis gaditana, showing that it is organized as a supercomplex including a core complex and an outer antenna, as in plants and other eukaryotic algae. Differently from all known organisms, the N. gaditana PSI supercomplex contains five peripheral antenna proteins, identified by proteome analysis as type-R light-harvesting complexes (LHCr4-8). Two antenna subunits are bound in a conserved position, as in PSI in plants, whereas three additional antennae are associated with the core on the other side. This peculiar antenna association correlates with the presence of PsaF/J and the absence of PsaH, G and K in the N. gaditana genome and proteome. Excitation energy transfer in the supercomplex is highly efficient, leading to a very high trapping efficiency as observed in all other PSI eukaryotes, showing that although the supramolecular organization of PSI changed during evolution, fundamental functional properties such as trapping efficiency were maintained
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