1,144 research outputs found
Visibility Representations of Boxes in 2.5 Dimensions
We initiate the study of 2.5D box visibility representations (2.5D-BR) where
vertices are mapped to 3D boxes having the bottom face in the plane and
edges are unobstructed lines of sight parallel to the - or -axis. We
prove that: Every complete bipartite graph admits a 2.5D-BR; The
complete graph admits a 2.5D-BR if and only if ; Every
graph with pathwidth at most admits a 2.5D-BR, which can be computed in
linear time. We then turn our attention to 2.5D grid box representations
(2.5D-GBR) which are 2.5D-BRs such that the bottom face of every box is a unit
square at integer coordinates. We show that an -vertex graph that admits a
2.5D-GBR has at most edges and this bound is tight. Finally,
we prove that deciding whether a given graph admits a 2.5D-GBR with a given
footprint is NP-complete. The footprint of a 2.5D-BR is the set of
bottom faces of the boxes in .Comment: Appears in the Proceedings of the 24th International Symposium on
Graph Drawing and Network Visualization (GD 2016
3D Visibility Representations of 1-planar Graphs
We prove that every 1-planar graph G has a z-parallel visibility
representation, i.e., a 3D visibility representation in which the vertices are
isothetic disjoint rectangles parallel to the xy-plane, and the edges are
unobstructed z-parallel visibilities between pairs of rectangles. In addition,
the constructed representation is such that there is a plane that intersects
all the rectangles, and this intersection defines a bar 1-visibility
representation of G.Comment: Appears in the Proceedings of the 25th International Symposium on
Graph Drawing and Network Visualization (GD 2017
Convergence properties of decays in chiral perturbation theory
Theoretical efforts to describe and explain the decays reach
far back in time. Even today, the convergence of the decay widths and some of
the Dalitz plot parameters seems problematic in low energy QCD. In the
framework of resummed CHPT, we explore the question of compatibility of
experimental data with a reasonable convergence of a carefully defined chiral
series, where NNLO remainders are assumed to be small. By treating the
uncertainties in the higher orders statistically, we numerically generate a
large set of theoretical predictions, which are then confronted with
experimental information. In the case of the decay widths, the experimental
values can be reconstructed for a reasonable range of the free parameters and
thus no tension is observed, in spite of what some of the traditional
calculations suggest. The Dalitz plot parameters and can be described
very well too. When the parameters and are concerned, we find a
mild tension for the whole range of the free parameters, at less than 2
C.L. This can be interpreted in two ways - either some of the higher order
corrections are indeed unexpectedly large or there is a specific configuration
of the remainders, which is, however, not completely improbable. Also, the
distribution of the theoretical uncertainties is found to be significantly
non-gaussian, so the consistency cannot be simply judged by the 1 error
bars.Comment: 57 pages, 5 figure
Are old-old patients with major depression more likely to relapse than young-old patients during continuation treatment with escitalopram?
<p>Abstract</p> <p>Background</p> <p>Escitalopram has shown efficacy and tolerability in the prevention of relapse in elderly patients with major depressive disorder (MDD). This <it>post-hoc </it>analysis compared time to relapse for <it>young-old </it>patients (n = 197) to that for <it>old-old </it>patients (n = 108).</p> <p>Method</p> <p>Relapse prevention: after 12-weeks open-label treatment, remitters (MADRS â¤12) were randomised to double-blind treatment with escitalopram or placebo and followed over 24-weeks. Patients were outpatients with MDD from 46 European centers aged âĽ75 years (<it>old-old</it>) or 65-74 years of age (<it>young-old</it>), treated with escitalopram 10-20mg/day. Efficacy was assessed using the Montgomery Ă
sberg Depression Rating Scale (MADRS).</p> <p>Results</p> <p>After open-label escitalopram treatment, a similar proportion of <it>young-old </it>patients (78%) and <it>old-old </it>patients (72%) achieved remission. In the analysis of time to relapse based on the Cox model (proportional hazards regression), with treatment and age group as covariates, the hazard ratio was 4.4 for placebo <it>versus </it>escitalopram (Ď<sup>2</sup>-test, df = 1, Ď<sup>2</sup>= 22.5, p < 0.001), whereas the effect of age was not significant, with a hazard ratio of 1.2 for <it>old-old </it>versus <it>young-old </it>(Ď<sup>2</sup>-test, df = 1, Ď<sup>2 </sup>= 0.41, p = 0.520). Escitalopram was well tolerated in both age groups with adverse events reported by 53.1% of <it>young-old </it>patients and 58.3% of <it>old-old </it>patients. There was no significant difference in withdrawal rates due to AEs between age groups (Ď<sup>2</sup>-test, Ď<sup>2 </sup>= 1.669, df = 1, p = 0.196).</p> <p>Conclusions</p> <p><it>Young-old </it>and <it>old-old </it>patients with MDD had comparable rates of remission after open-label escitalopram, and both age groups had much lower rates of relapse on escitalopram than on placebo.</p
Heterogeneous Response to a Quorum-Sensing Signal in the Luminescence of Individual Vibrio fischeri
The marine bacterium Vibrio fischeri regulates its bioluminescence through a quorum sensing mechanism: the bacterium releases diffusible small molecules (autoinducers) that accumulate in the environment as the population density increases. This accumulation of autoinducer (AI) eventually activates transcriptional regulators for bioluminescence as well as host colonization behaviors. Although V.fischeri quorum sensing has been extensively characterized in bulk populations, far less is known about how it performs at the level of the individual cell, where biochemical noise is likely to limit the precision of luminescence regulation. We have measured the time-dependence and AI-dependence of light production by individual V.fischeri cells that are immobilized in a perfusion chamber and supplied with a defined concentration of exogenous AI. We use low-light level microscopy to record and quantify the photon emission from the cells over periods of several hours as they respond to the introduction of AI. We observe an extremely heterogeneous response to the AI signal. Individual cells differ widely in the onset time for their luminescence and in their resulting brightness, even in the presence of high AI concentrations that saturate the light output from a bulk population. The observed heterogeneity shows that although a given concentration of quorum signal may determine the average light output from a population of cells, it provides far weaker control over the luminescence output of each individual cell
The Origin Recognition Complex Interacts with a Subset of Metabolic Genes Tightly Linked to Origins of Replication
The origin recognition complex (ORC) marks chromosomal sites as replication origins and is essential for replication initiation. In yeast, ORC also binds to DNA elements called silencers, where its primary function is to recruit silent information regulator (SIR) proteins to establish transcriptional silencing. Indeed, silencers function poorly as chromosomal origins. Several genetic, molecular, and biochemical studies of HMR-E have led to a model proposing that when ORC becomes limiting in the cell (such as in the orc2-1 mutant) only sites that bind ORC tightly (such as HMR-E) remain fully occupied by ORC, while lower affinity sites, including many origins, lose ORC occupancy. Since HMR-E possessed a unique non-replication function, we reasoned that other tight sites might reveal novel functions for ORC on chromosomes. Therefore, we comprehensively determined ORC âaffinityâ genome-wide by performing an ORC ChIPâonâchip in ORC2 and orc2-1 strains. Here we describe a novel group of orc2-1âresistant ORCâinteracting chromosomal sites (ORFâORC sites) that did not function as replication origins or silencers. Instead, ORFâORC sites were comprised of protein-coding regions of highly transcribed metabolic genes. In contrast to the ORCâsilencer paradigm, transcriptional activation promoted ORC association with these genes. Remarkably, ORFâORC genes were enriched in proximity to origins of replication and, in several instances, were transcriptionally regulated by these origins. Taken together, these results suggest a surprising connection among ORC, replication origins, and cellular metabolism
Ratio of the Isolated Photon Cross Sections at \sqrt{s} = 630 and 1800 GeV
The inclusive cross section for production of isolated photons has been
measured in \pbarp collisions at GeV with the \D0 detector at
the Fermilab Tevatron Collider. The photons span a transverse energy ()
range from 7-49 GeV and have pseudorapidity . This measurement is
combined with to previous \D0 result at GeV to form a ratio
of the cross sections. Comparison of next-to-leading order QCD with the
measured cross section at 630 GeV and ratio of cross sections show satisfactory
agreement in most of the range.Comment: 7 pages. Published in Phys. Rev. Lett. 87, 251805, (2001
Search for Gravitational Waves from Primordial Black Hole Binary Coalescences in the Galactic Halo
We use data from the second science run of the LIGO gravitational-wave
detectors to search for the gravitational waves from primordial black hole
(PBH) binary coalescence with component masses in the range 0.2--.
The analysis requires a signal to be found in the data from both LIGO
observatories, according to a set of coincidence criteria. No inspiral signals
were found. Assuming a spherical halo with core radius 5 kpc extending to 50
kpc containing non-spinning black holes with masses in the range 0.2--, we place an observational upper limit on the rate of PBH coalescence
of 63 per year per Milky Way halo (MWH) with 90% confidence.Comment: 7 pages, 4 figures, to be submitted to Phys. Rev.
The social biography of antibiotic use in smallholder dairy farms in India
Background Antimicrobial resistance (AMR) has been identified as one of the major threats to global health, food security and development today. While there has been considerable attention about the use and misuse of antibiotics amongst human populations in both research and policy environments, there is no definitive estimate of the extent of misuse of antibiotics in the veterinary sector and its contribution to AMR in humans. In this study, we explored the drivers ofirrational usage of verterinary antibiotics in the dairy farming sector in peri-urban India. Methods and materials The study was conducted in the peri-urban belts of Ludhiana, Guwahati and Bangalore. A total of 54 interviews (formal and non-formal) were carried out across these three sites. Theme guides were developed to explore different drivers of veterinary antimicrobial use. Data was audio recorded and transcribed. Analysis of the coded data set was carried out using AtlasTi. Version 7. Themes emerged inductively from the set of codes. Results Findings were presented based on concept of âlevels of analysesâ. Emergent themes were categorised as individual, health systems, and policy level drivers. Low level of knowledge related to antibiotics among farmers, active informal service providers, direct marketing of drugs to the farmers and easily available antibiotics, dispensed without appropriate prescriptions contributed to easy access to antibiotics, and were identified to be the possible drivers contributing to the non-prescribed and self-administered use of antibiotics in the dairy farms. Conclusions Smallholding dairy farmers operated within very small margins of profits. The paucity of formal veterinary services at the community level, coupled with easy availability of antibiotics and the need to ensure profits and minimise losses, promoted non-prescribed antibiotic consumption. It is essential that these local drivers of irrational antibiotic use are understood in order to develop interventions and policies that seek to reduce antibiotic misuse
Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV
The performance of muon reconstruction, identification, and triggering in CMS
has been studied using 40 inverse picobarns of data collected in pp collisions
at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection
criteria covering a wide range of physics analysis needs have been examined.
For all considered selections, the efficiency to reconstruct and identify a
muon with a transverse momentum pT larger than a few GeV is above 95% over the
whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4,
while the probability to misidentify a hadron as a muon is well below 1%. The
efficiency to trigger on single muons with pT above a few GeV is higher than
90% over the full eta range, and typically substantially better. The overall
momentum scale is measured to a precision of 0.2% with muons from Z decays. The
transverse momentum resolution varies from 1% to 6% depending on pseudorapidity
for muons with pT below 100 GeV and, using cosmic rays, it is shown to be
better than 10% in the central region up to pT = 1 TeV. Observed distributions
of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO
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