825 research outputs found
Signal Processing and Classification Tools for Intelligent Distributed Monitoring and Analysis of the Smart Grid
This paper proposes a novel framework for an intelligent monitoring system that supervises the performance of the future power system. The increased complexity of the power system could endanger the reliability, voltage quality, operational security or resilience of the power system. A distributed structure for such a monitoring system is described and some of the advanced signal processing techniques or tools that could be used in such a monitoring system are given. Several examples for seeking the spatial locations and finding the underlying causes of disturbances are included
A Method to Evaluate Harmonic Model-Based Estimations under Non-White Measured Noise
Automatic extracting information from power-system event recordings requires applications of signal-processing estimation techniques whose performance has been verified under white noise. This paper proposes a method to test these techniques under real power-system noise, which is very different from white noise, to evaluate their application feasibility. The first part of the paper describes the evaluation method used to evaluate the techniques in a statistical sense and a method to extract noise from measured power-system recordings. The second part of the paper focuses on the evaluation of a number of
harmonic model-based techniques under non-white noise, including: Kalman filter, MUSIC, ESPRIT, and segmentation algorithms. The paper shows that for the Kalman filter, a very high order with high computational burden is necessary only if high frequency components are of interest. The application of MUSIC, ESPRIT, and the segmentation algorithms under natural power-system noise is shown to be
feasible
Chemical telemetry of OH observed to measure interstellar magnetic fields
We present models for the chemistry in gas moving towards the ionization
front of an HII region. When it is far from the ionization front, the gas is
highly depleted of elements more massive than helium. However, as it approaches
the ionization front, ices are destroyed and species formed on the grain
surfaces are injected into the gas phase. Photodissociation removes gas phase
molecular species as the gas flows towards the ionization front. We identify
models for which the OH column densities are comparable to those measured in
observations undertaken to study the magnetic fields in star forming regions
and give results for the column densities of other species that should be
abundant if the observed OH arises through a combination of the liberation of
H2O from surfaces and photodissociation. They include CH3OH, H2CO, and H2S.
Observations of these other species may help establish the nature of the OH
spatial distribution in the clouds, which is important for the interpretation
of the magnetic field results.Comment: 11 pages, 2 figures, accepted by Astrophysics and Space Scienc
Hypocholesterolemic phospholipid transfer protein knockout mice exhibit a normal glucocorticoid response to food deprivation
Objectives: Glucocorticoids, adrenal-derived steroid hormones, facilitate the physiological response to stress. High-density lipoproteins (HDL) are considered the primary source of cholesterol used for glucocorticoid synthesis in mice. Phospholipid transfer protein (PLTP) is a key player in HDL formation. In the current study we tested the hypothesis that HDL deficiency associated with genetic lack of PLTP negatively impacts the adrenal steroid function. Methods: We determined the glucocorticoid response to overnight food deprivation stress and the adrenal lipid and genetic phenotype of wild-type and PLTP knockout mice. Results: Basal plasma corticosterone levels, adrenal weights, and adrenocortical neutral lipid stores were not different between wild-type and PLTP knockout mice. Strikingly, plasma corticosterone levels were also equally high in the two groups of mice under fasting conditions (twoway ANOVA genotype effect: P>0.05). However, compensatory mechanisms were active to overcome adrenal lipid depletion, since gene expression levels of cholesterol synthesis, acquisition and mobilization proteins were similar to 2-fold higher in PLTP knockout adrenals versus wild-type adrenals. In support of an overall similar glucocorticoid stress response, hepatic relative mRNA expression levels of the glucocorticoid receptor target/glucocorticoid-sensitive genes PEPCK, ANGPTL4, FGF21, TDO2 and HMGCS2 were also not different. Conclusions: We have shown that hypocholesterolemic PLTP knockout mice exhibit a normal glucocorticoid response to food deprivation. These novel data (1) highlight that the effect of HDL deficiency on adrenal glucocorticoid output in mice is model dependent and (2) imply that other (lipoprotein) cholesterol sources than HDL can also generate the pool utilized by adrenocortical cells to synthesize glucocorticoids.Toxicolog
A Distinct Gene Module for Dysfunction Uncoupled from Activation in Tumor-Infiltrating T Cells
Reversing the dysfunctional T cell state that arises in cancer and chronic viral infections is the focus of therapeutic interventions; however, current therapies are effective in only some patients and some tumor types. To gain a deeper molecular understanding of the dysfunctional T cell state, we analyzed population and single-cell RNA profiles of CD8+tumor-infiltrating lymphocytes (TILs) and used genetic perturbations to identify a distinct gene module for T cell dysfunction that can be uncoupled from T cell activation. This distinct dysfunction module is downstream of intracellular metallothioneins that regulate zinc metabolism and can be identified at single-cell resolution. We further identify Gata-3, a zinc-finger transcription factor in the dysfunctional module, as a regulator of dysfunction, and we use CRISPR-Cas9 genome editing to show that it drives a dysfunctional phenotype in CD8+TILs. Our results open novel avenues for targeting dysfunctional T cell states while leaving activation programs intact
The energy spectrum of all-particle cosmic rays around the knee region observed with the Tibet-III air-shower array
We have already reported the first result on the all-particle spectrum around
the knee region based on data from 2000 November to 2001 October observed by
the Tibet-III air-shower array. In this paper, we present an updated result
using data set collected in the period from 2000 November through 2004 October
in a wide range over 3 decades between eV and eV, in which
the position of the knee is clearly seen at around 4 PeV. The spectral index is
-2.68 0.02(stat.) below 1PeV, while it is -3.12 0.01(stat.) above 4
PeV in the case of QGSJET+HD model, and various systematic errors are under
study now.Comment: 12 pages, 7 figures, accepted by Advances in space researc
Moon Shadow by Cosmic Rays under the Influence of Geomagnetic Field and Search for Antiprotons at Multi-TeV Energies
We have observed the shadowing of galactic cosmic ray flux in the direction
of the moon, the so-called moon shadow, using the Tibet-III air shower array
operating at Yangbajing (4300 m a.s.l.) in Tibet since 1999. Almost all cosmic
rays are positively charged; for that reason, they are bent by the geomagnetic
field, thereby shifting the moon shadow westward. The cosmic rays will also
produce an additional shadow in the eastward direction of the moon if cosmic
rays contain negatively charged particles, such as antiprotons, with some
fraction. We selected 1.5 x10^{10} air shower events with energy beyond about 3
TeV from the dataset observed by the Tibet-III air shower array and detected
the moon shadow at level. The center of the moon was detected
in the direction away from the apparent center of the moon by 0.23 to
the west. Based on these data and a full Monte Carlo simulation, we searched
for the existence of the shadow produced by antiprotons at the multi-TeV energy
region. No evidence of the existence of antiprotons was found in this energy
region. We obtained the 90% confidence level upper limit of the flux ratio of
antiprotons to protons as 7% at multi-TeV energies.Comment: 13pages,4figures; Accepted for publication in Astroparticle Physic
Characterization of the n-TOF EAR-2 neutron beam
The experimental area 2 (EAR-2) at CERNs neutron time-of-flight facility (n-TOF), which is operational since 2014, is designed and built as a short-distance complement to the experimental area 1 (EAR-1). The Parallel Plate Avalanche Counter (PPAC) monitor experiment was performed to characterize the beam prole and the shape of the neutron 'ux at EAR-2. The prompt Îł-flash which is used for calibrating the time-of-flight at EAR-1 is not seen by PPAC at EAR-2, shedding light on the physical origin of this Îł-flash
Understanding the Chemical Complexity in Circumstellar Envelopes of C-rich AGB Stars: the Case of IRC +10216
The circumstellar envelopes of carbon-rich AGB stars show a chemical
complexity that is exemplified by the prototypical object IRC +10216, in which
about 60 different molecules have been detected to date. Most of these species
are carbon chains of the type CnH, CnH2, CnN, HCnN. We present the detection of
new species (CH2CHCN, CH2CN, H2CS, CH3CCH and C3O) achieved thanks to the
systematic observation of the full 3 mm window with the IRAM 30m telescope plus
some ARO 12m observations. All these species, known to exist in the
interstellar medium, are detected for the first time in a circumstellar
envelope around an AGB star. These five molecules are most likely formed in the
outer expanding envelope rather than in the stellar photosphere. A pure gas
phase chemical model of the circumstellar envelope is reasonably successful in
explaining the derived abundances, and additionally allows to elucidate the
chemical formation routes and to predict the spatial distribution of the
detected species.Comment: 4 pages, 4 figures; to appear in Astrophysics and Space Science,
special issue of "Science with ALMA: a new era for Astrophysics" conference,
November, 13-17 2006, ed. R. Bachille
Measurement of the Lifetime of the Tau Lepton
The tau lepton lifetime is measured with the L3 detector at LEP using the
complete data taken at centre-of-mass energies around the Z pole resulting in
tau_tau = 293.2 +/- 2.0 (stat) +/- 1.5 (syst) fs. The comparison of this result
with the muon lifetime supports lepton universality of the weak charged current
at the level of six per mille. Assuming lepton universality, the value of the
strong coupling constant, alpha_s is found to be alpha_s(m_tau^2) = 0.319 +/-
0.015(exp.) +/- 0.014 (theory)
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