2,163 research outputs found
Large Scale Job Management and Experience in Recent Data Challenges within the LHC CMS experiment
From its conception the job management system has been distributed to increase scalability and robustness. The system consists of several applications (called ProdAgents) which manage Monte Carlo, reconstruction and skimming jobs on collections of sites within different Grid environments (OSG, NorduGrid, LCG) and submission systems such as GlideIn, local batch, etc...
Production of simulated data in CMS mainly takes place on so called Tier2s (small to medium size computing centers) resources. Approximately ~50% of the CMS Tier2 resources are allocated to running simulation jobs. While the so-called Tier1s (medium to large size computing centers with high capacity tape storage systems) will be mainly used for skimming and reconstructing detector data. During the last one and a half years the job management system has been adapted such that it can be configured to convert Data Acquisition (DAQ) / High Level Trigger (HLT) output from the CMS detector to the CMS data format and manage the real time data stream from the experiment. Simultaneously the system has been upgraded to facilitate the increasing scale of the CMS production and adapting to the procedures used by its operators.
In this paper we discuss the current (high level) architecture of ProdAgent, the experience in using this system in computing challenges, feedback from these challenges, and future work including migration to a set of core libraries to facilitate convergence between the different data management projects within CMS that deal with analysis, simulation, and initial reconstruction of real data. This migration is important, as it will decrease the code footprint used by these projects and increase maintainability of the code base
Alteration of the in vivo nicotinic receptor density in ADNFLE patients: a PET study
Nicotinic acetylcholine receptors (nAChRs) are involved in a familial form of frontal lobe epilepsy, autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE). In several ADNFLE families, mutations were identified in the nAChR α4 or ÎČ2 subunit, which together compose the main cerebral nAChR. Electrophysiological assessment using in vitro expression systems indicated a gain of function of the mutant receptors. However the precise mechanisms by which they contribute to the pathogenesis of a focal epilepsy remain obscure, especially since α4ÎČ2 nAChRs are known to be widely distributed within the entire brain. PET study using [18F]-F-A-85380, a high affinity agonist at the α4ÎČ2 nAChRs, allows the determination of the regional distribution and density of the nAChRs in healthy volunteers and in ADNFLE patients, thus offering a unique opportunity to investigate some in vivo consequences of the molecular defect. We have assessed nAChR distribution in eight non-smoking ADNFLE patients (from five families) bearing an identified mutation in nAChRs and in seven age-matched non-smoking healthy volunteers using PET and [18F]-F-A-85380. Parametric images of volume of distribution (Vd) were generated as the ratio of tissue to plasma radioactivities. The images showed a clear difference in the pattern of the nAChR density in the brains of the patients compared to the healthy volunteers. Vd values revealed a significant increase (between 12 and 21%, P < 0.05) in the ADNFLE patients in the mesencephalon, the pons and the cerebellum when compared to control subjects. Statistical parametric mapping (SPM) was then used to better analyse subtle regional differences. This analysis confirmed clear regional differences between patients and controls: patients had increased nAChR density in the epithalamus, ventral mesencephalon and cerebellum, but decreased nAChR density in the right dorsolateral prefrontal region. In five patients who underwent an additional [18F]-fluorodeoxyglucose (FDG) PET experiment, hypometabolism was observed in the neighbouring area of the right orbitofrontal cortex. The demonstration of a regional nAChR density decrease in the prefrontal cortex, despite the known distribution of these receptors throughout the cerebral cortex, is consistent with a focal epilepsy involving the frontal lobe. We also propose that the nAChR density increase in mesencephalon is involved in the pathophysiology of ADNFLE through the role of brainstem ascending cholinergic systems in arousa
Comparison of metal-based nanoparticles and nanowires: Solubility, reactivity, bioavailability and cellular toxicity
While the toxicity of metal-based nanoparticles (NP) has been investigated in an increasing number of studies, little is known about metal-based fibrous materials, so-called nanowires (NWs). Within the present study, the physico-chemical properties of particulate and fibrous nanomaterials based on Cu, CuO, Ni, and Ag as well as TiO and CeO NP were characterized and compared with respect to abiotic metal ion release in different physiologically relevant media as well as acellular reactivity. While none of the materials was soluble at neutral pH in artificial alveolar fluid (AAF), Cu, CuO, and Ni-based materials displayed distinct dissolution under the acidic conditions found in artificial lysosomal fluids (ALF and PSF). Subsequently, four different cell lines were applied to compare cytotoxicity as well as intracellular metal ion release in the cytoplasm and nucleus. Both cytotoxicity and bioavailability reflected the acellular dissolution rates in physiological lysosomal media (pH 4.5); only Ag-based materials showed no or very low acellular solubility, but pronounced intracellular bioavailability and cytotoxicity, leading to particularly high concentrations in the nucleus. In conclusion, in spite of some quantitative differences, the intracellular bioavailability as well as toxicity is mostly driven by the respective metal and is less modulated by the shape of the respective NP or NW
Change of composition and diversity of species and grassland management between different grazing intensity in Pannonian dry and wet grasslands
Investigations were carried out in wet and dry pasture. Coenological recordings were taken in
three zones. The first zone (âAâ) located 0-50 m near the stable, second zone (âBâ) located 50-150 m
from the stable, while the third zone (âCâ) located farther than 150 m. We have carried out analyses of
ecological and environmental factors and life form types. Based on our results for both dry and wet
grasslands, quadrates of âAâ zone were well isolated from the rest of the zones. Overgrazing, which
involves considerable trampling, vanishes differences among vegetations, thereby promotes weed and
disturbance tolerant rich vegetation. The lowest species number and diversity could be found here. Due to
the nitrogen enrichment due to the constant presence of livestock, drier and less heat demanding habitat
developed in the âAâ zones, according to the environmental indicators. Because of the change in
management, conservation and diversity values of âCâ zone increased, however, according to nature
protection values it underperformed compared to âBâ zone. According to the sample area, wet grasslands
from the sandy areas of KiskunsĂĄg, preserve nature protection values and grass composition better
moving away from stables, due to less grazing pressure. Drier backgrounds tolerate stronger grazing
pressure
Mechanical Stress Inference for Two Dimensional Cell Arrays
Many morphogenetic processes involve mechanical rearrangement of epithelial
tissues that is driven by precisely regulated cytoskeletal forces and cell
adhesion. The mechanical state of the cell and intercellular adhesion are not
only the targets of regulation, but are themselves likely signals that
coordinate developmental process. Yet, because it is difficult to directly
measure mechanical stress {\it in vivo} on sub-cellular scale, little is
understood about the role of mechanics of development. Here we present an
alternative approach which takes advantage of the recent progress in live
imaging of morphogenetic processes and uses computational analysis of high
resolution images of epithelial tissues to infer relative magnitude of forces
acting within and between cells. We model intracellular stress in terms of bulk
pressure and interfacial tension, allowing these parameters to vary from cell
to cell and from interface to interface. Assuming that epithelial cell layers
are close to mechanical equilibrium, we use the observed geometry of the two
dimensional cell array to infer interfacial tensions and intracellular
pressures. Here we present the mathematical formulation of the proposed
Mechanical Inverse method and apply it to the analysis of epithelial cell
layers observed at the onset of ventral furrow formation in the {\it
Drosophila} embryo and in the process of hair-cell determination in the avian
cochlea. The analysis reveals mechanical anisotropy in the former process and
mechanical heterogeneity, correlated with cell differentiation, in the latter
process. The method opens a way for quantitative and detailed experimental
tests of models of cell and tissue mechanics
Collective and single cell behavior in epithelial contact inhibition
Control of cell proliferation is a fundamental aspect of tissue physiology
central to morphogenesis, wound healing and cancer. Although many of the
molecular genetic factors are now known, the system level regulation of growth
is still poorly understood. A simple form of inhibition of cell proliferation
is encountered in vitro in normally differentiating epithelial cell cultures
and is known as "contact inhibition". The study presented here provides a
quantitative characterization of contact inhibition dynamics on tissue-wide and
single cell levels. Using long-term tracking of cultured MDCK cells we
demonstrate that inhibition of cell division in a confluent monolayer follows
inhibition of cell motility and sets in when mechanical constraint on local
expansion causes divisions to reduce cell area. We quantify cell motility and
cell cycle statistics in the low density confluent regime and their change
across the transition to epithelial morphology which occurs with increasing
cell density. We then study the dynamics of cell area distribution arising
through reductive division, determine the average mitotic rate as a function of
cell size and demonstrate that complete arrest of mitosis occurs when cell area
falls below a critical value. We also present a simple computational model of
growth mechanics which captures all aspects of the observed behavior. Our
measurements and analysis show that contact inhibition is a consequence of
mechanical interaction and constraint rather than interfacial contact alone,
and define quantitative phenotypes that can guide future studies of molecular
mechanisms underlying contact inhibition
The paradox of the binomial Ixodes ricinus activity and the observed unimodal Lyme borreliosis season in Hungary
The change of ambient temperature plays a key role in determining the run of the annual Lyme season. Our aim was to explain the apparent contradiction between the
annual unimodal Lyme borreliosis incidence and the bimodal Ixodes ricinus tick activity run â both observed in Hungary â by distinguishing the temperaturedependent seasonal human and tick activity, the temperature-independent factors, and
the multiplicative effect of human outdoor activity in summer holiday, using data from Hungary in the period of 1998â2012. This separation was verified by modeling
the Lyme incidence based on the separated factors, and comparing the run of the observed and modeled incidence. We demonstrated the bimodality of tick season by using the originally unimodal Lyme incidence data. To model the outdoor human activity, the amount of camping guest nights was used, which showed an irregular run from mid-June to September. The human outdoor activity showed a similar
exponential correlation with ambient temperature to that what the relative incidence did. It was proved that summer holiday has great influence on Lyme incidence
Speech rhythm: a metaphor?
Is speech rhythmic? In the absence of evidence for a traditional view that languages strive to coordinate either syllables or stress-feet with regular time intervals, we consider the alternative that languages exhibit contrastive rhythm subsisting merely in the alternation of stronger and weaker elements. This is initially plausible, particularly for languages with a steep âprominence gradientâ, i.e. a large disparity between stronger and weaker elements; but we point out that alternation is poorly achieved even by a âstress-timedâ language such as English, and, historically, languages have conspicuously failed to adopt simple phonological remedies that would ensure alternation. Languages seem more concerned to allow âsyntagmatic contrastâ between successive units and to use durational effects to support linguistic functions than to facilitate rhythm. Furthermore, some languages (e.g. Tamil, Korean) lack the lexical prominence which would most straightforwardly underpin prominence alternation. We conclude that speech is not incontestibly rhythmic, and may even be antirhythmic. However, its linguistic structure and patterning allow the metaphorical extension of rhythm in varying degrees and in different ways depending on the language, and that it is this analogical process which allows speech to be matched to external rhythms
New Class of Eigenstates in Generic Hamiltonian Systems
In mixed systems, besides regular and chaotic states, there are states
supported by the chaotic region mainly living in the vicinity of the hierarchy
of regular islands. We show that the fraction of these hierarchical states
scales as and relate the exponent to the
decay of the classical staying probability . This is
numerically confirmed for the kicked rotor by studying the influence of
hierarchical states on eigenfunction and level statistics.Comment: 4 pages, 3 figures, Phys. Rev. Lett., to appea
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