469 research outputs found
How much time does a measurement take?
We consider the problem of measurement using the Lindblad equation, which
allows the introduction of time in the interaction between the measured system
and the measurement apparatus. We use analytic results, valid for weak
system-environment coupling, obtained for a two-level system in contact with a
measurer (Markovian interaction) and a thermal bath (non-Markovian
interaction), where the measured observable may or may not commute with the
system-environment interaction. Analysing the behavior of the coherence, which
tends to a value asymptotically close to zero, we obtain an expression for the
time of measurement which depends only on the system-measurer coupling, and
which does not depend on whether the observable commutes with the system-bath
interaction. The behavior of the coherences in the case of strong
system-environment coupling, found numerically, indicates that an increase in
this coupling decreases the measurement time, thus allowing our expression to
be considered the upper limit for the duration of the process.Comment: REVISED VERSION: 17 pages, 2 figure
Investigating associations between health-related quality of life and endocrine therapy underuse in women with early-stage breast cancer
Purpose Endocrine therapy (ET) underuse puts women at increased risk for breast cancer (BC) recurrence. Our objective was to determine if health-related quality of life (HRQOL) subgroups were associated with underuse. Methods Data came from the third phase of the Carolina Breast Cancer Study. We included 1,599 women with hormone receptor-positiveBCage 20 to 74 years.HRQOLwas measured, on average,5months postdiagnosis. Subgroups were derived using latent profile (LP) analysis. Underuse was defined as not initiating or adhering to ET by 36 months postdiagnosis. Multivariable logistic regression models estimated adjusted odds ratios (ORs) between HRQOL LPs and underuse. The best HRQOL LP was the reference. Chemotherapy- and race-stratified models were estimated, separately. Results Initiation analyses included 953womenwhohad not begun ET by their 5-month survey. Of these, 154 never initiated ET. Adherence analyses included 1,114 ET initiators, of whom 211 were nonadherent.HRQOLwas not significantly associated with noninitiation, except among nonchemotherapy users, with membership in the poorest LP associated with increased odds of noninitiation (adjusted OR, 5.5; 95% CI, 1.7 to 17.4). Membership in the poorest LPs was associated with nonadherence (LP1: adjusted OR, 2.2; 95% CI, 1.2 to 4.0 and LP2: adjusted OR,1.9;95%CI, 1.1 to 3.6). Membershipin the poorestLPwasassociated with nonadherence among nonchemotherapy users (adjusted OR, 2.1; 95% CI, 1.2 to 5.1). Conclusion Ourresults suggestwomenwith poorHRQOLduring active treatmentmaybe at increased risk for ET underuse. Focusing on HRQOL, a modifiable factor, may improve targeting of future interventions early in theBCcontinuum to improve ET initiation and adherence and prevent BC recurrence
Examining health-related quality of life patterns in women with breast cancer
Purpose: We aimed to identify subgroups of women with breast cancer who experience different health-related quality of life (HRQOL) patterns during active treatment and survivorship and determine characteristics associated with subgroup membership. Methods: We used data from the third phase of the population-based Carolina Breast Cancer Study and included 2142 women diagnosed with breast cancer from 2008 to 2013. HRQOL was measured, on average, 5 and 25 months post diagnosis. Latent profile analysis was used to identify HRQOL latent profiles (LPs) at each time point. Latent transition analysis was used to determine probabilities of women transitioning profiles from 5 to 25 months. Multinomial logit models estimated adjusted odds ratios (aORs) and 95% confidence intervals for associations between patient characteristics and LP membership at each time point. Results: We identified four HRQOL LPs at 5 and 25 months. LP1 had the poorest HRQOL and LP4 the best. Membership in the poorest profile at 5 months was associated with younger age aOR 0.95; 0.93–0.96, White race aOR 1.48; 1.25–1.65, being unmarried aOR 1.50; 1.28–1.65 and having public aOR 3.09; 1.96–4.83 or no insurance aOR 6.51; 2.12–20.10. At 25 months, Black race aOR 1.75; 1.18–1.82 was associated with the poorest profile membership. Black race and smoking were predictors of deteriorating to a worse profile from 5 to 25 months. Conclusions: Our results suggest patient-level characteristics including age at diagnosis and race may identify women at risk for experiencing poor HRQOL patterns. If women are identified and offered targeted HRQOL support, we may see improvements in long-term HRQOL and better breast cancer outcomes
Implications of structural inheritance in oblique rift zones for basin compartmentalization: Nkhata Basin, Malawi Rift (EARS)
The Cenozoic East African Rift System (EARS) is an exceptional example of active continental extension, providing opportunities for furthering our understanding of hydrocarbon plays within rifts. It is divided into structurally distinct western and eastern branches. The western branch comprises deep rift basins separated by transfer zones, commonly localised onto pre-existing structures, offering good regional scale hydrocarbon traps. At a basin-scale, local discrete inherited structures might also play an important role on fault localisation and hydrocarbon distribution. Here, we consider the evolution of the Central basin of the Malawi Rift, in particular the influence of pre-existing structural fabrics.Integrating basin-scale multichannel 2D, and high resolution seismic datasets we constrain the border, Mlowe-Nkhata, fault system (MNF) to the west of the basin and smaller Mbamba fault (MF) to the east and document their evolution. Intra basin structures define a series of horsts, which initiated as convergent transfers, along the basin axis. The horsts are offset along a NE-SW striking transfer fault parallel to and along strike of the onshore Karoo (Permo-Triassic) Ruhuhu graben. Discrete pre-existing structures probably determined its location and, oriented obliquely to the extension orientation it accommodated predominantly strike-slip deformation, with more slowly accrued dip-slip.To the north of this transfer fault, the overall basin architecture is asymmetric, thickening to the west throughout; while to the south, an initially symmetric graben architecture became increasingly asymmetric in sediment distribution as strain localised onto the western MNF. The presence of the axial horst increasingly focussed sediment supply to the west. As the transfer fault increased its displacement, so this axial supply was interrupted, effectively starving the south-east while ponding sediments between the western horst margin and the transfer fault. This asymmetric bathymetry and partitioned sedimentation continues to the present-day, overprinting the early basin symmetry and configuration. Sediments deposited earlier become increasingly dissected and fault juxtapositions changed at a small (10-100 m) scale. The observed influence of basin-scale transfer faults on sediment dispersal and fault compartmentalization due to pre-existing structures oblique to the extension orientation is relevant to analogous exploration settings
Impacts of local human activities on the Antarctic environment
We review the scientific literature, especially from the past decade, on the impacts of human activities on the Antarctic environment. A range of impacts has been identified at a variety of spatial and temporal scales. Chemical contamination and sewage disposal on the continent have been found to be long-lived. Contemporary sewage management practices at many coastal stations are insufficient to prevent local contamination but no introduction of non-indigenous organisms through this route has yet been demonstrated. Human activities, particularly construction and transport, have led to disturbances of flora and fauna. A small number of non-indigenous plant and animal species has become established, mostly on the northern Antarctic Peninsula and southern archipelagos of the Scotia Arc. There is little indication of recovery of overexploited fish stocks, and ramifications of fishing activity oil bycatch species and the ecosystem could also be far-reaching. The Antarctic Treaty System and its instruments, in particular the Convention for the Conservation of Antarctic Marine Living Resources and the Environmental Protocol, provide a framework within which management of human activities take place. In the face of the continuing expansion of human activities in Antarctica, a more effective implementation of a wide range of measures is essential, in order to ensure comprehensive protection of the Antarctic environment, including its intrinsic, wilderness and scientific values which remains a fundamental principle of the Antarctic Treaty System. These measures include effective environmental impact assessments, long-term monitoring, mitigation measures for non-indigenous species, ecosystem-based management of living resources, and increased regulation of National Antarctic Programmes and tourism activities
IGF-1 does not moderate the time-dependent transcriptional patterns of key homeostatic genes induced by sustained compression of bovine cartilage
Objective
To determine changes in chondrocyte transcription of a range of anabolic, catabolic and signaling genes following simultaneous treatment of cartilage with Insulin-like growth factor-1 (IGF-1) and ramp-and-hold mechanical compression, and compare with effects on biosynthesis.
Methods
Explant disks of bovine calf cartilage were slowly compressed (unconfined) over 3-min to their 1 mm cut-thickness (0%-compression) or to 50%-compression with or without 300 ng/ml IGF-1. Expression of 24 genes involved in cartilage homeostasis was measured using qPCR at 2, 8, 24, 32, 48 h after compression ±IGF-1. Clustering analysis was used to identify groups of co-expressed genes to further elucidate mechanistic pathways.
Results
IGF-1 alone stimulated gene expression of aggrecan and collagen II, but simultaneous 24h compression suppressed this effect. Compression alone up-regulated expression of matrix metalloproteinase (MMP)-3, MMP-13, a disintegrin and metalloproteinase with thrombospondin motif (ADAMTS)-5 and transforming growth factor (TGF)-β, an effect not reversed by simultaneous IGF-1 treatment. Temporal changes in expression following IGF-1 treatment were generally slower than that following compression. Clustering analysis revealed five distinct groups within which the pairings, tissue inhibitor of metalloproteinase (TIMP)-3 and ADAMTS-5, MMP-1 and IGF-2, and IGF-1 and Collagen II, were all robustly co-expressed, suggesting inherent regulation and feedback in chondrocyte gene expression. While aggrecan synthesis was transcriptionally regulated by IGF-1, inhibition of aggrecan synthesis by sustained compression appeared post-transcriptionally regulated.
Conclusion
Sustained compression markedly altered the effects of IGF-1 on expression of genes involved in cartilage homeostasis, while IGF-1 was largely unable to moderate the transcriptional effects of compression alone. The demonstrated co-expressed gene pairings suggest a balance of anabolic and catabolic activity following simultaneous mechanical and growth factor stimuli.National Institutes of Health (U.S.) (grant R01-AR33236)National Institutes of Health (U.S.) (grant R01-HG003352)National Institutes of Health (U.S.) (grant P42-ES04699)National Institutes of Health (U.S.) (grant T32-EB006348
Measurement-based quantum foundations
I show that quantum theory is the only probabilistic framework that permits
arbitrary processes to be emulated by sequences of local measurements. This
supports the view that, contrary to conventional wisdom, measurement should not
be regarded as a complex phenomenon in need of a dynamical explanation but
rather as a primitive -- and perhaps the only primitive -- operation of the
theory.Comment: 8 pages, version to appear in Found. Phy
Metal enrichment processes
There are many processes that can transport gas from the galaxies to their
environment and enrich the environment in this way with metals. These metal
enrichment processes have a large influence on the evolution of both the
galaxies and their environment. Various processes can contribute to the gas
transfer: ram-pressure stripping, galactic winds, AGN outflows, galaxy-galaxy
interactions and others. We review their observational evidence, corresponding
simulations, their efficiencies, and their time scales as far as they are known
to date. It seems that all processes can contribute to the enrichment. There is
not a single process that always dominates the enrichment, because the
efficiencies of the processes vary strongly with galaxy and environmental
properties.Comment: 18 pages, 8 figures, accepted for publication in Space Science
Reviews, special issue "Clusters of galaxies: beyond the thermal view",
Editor J.S. Kaastra, Chapter 17; work done by an international team at the
International Space Science Institute (ISSI), Bern, organised by J.S.
Kaastra, A.M. Bykov, S. Schindler & J.A.M. Bleeke
An Integrated TCGA Pan-Cancer Clinical Data Resource to Drive High-Quality Survival Outcome Analytics
For a decade, The Cancer Genome Atlas (TCGA) program collected clinicopathologic annotation data along with multi-platform molecular profiles of more than 11,000 human tumors across 33 different cancer types. TCGA clinical data contain key features representing the democratized nature of the data collection process. To ensure proper use of this large clinical dataset associated with genomic features, we developed a standardized dataset named the TCGA Pan-Cancer Clinical Data Resource (TCGA-CDR), which includes four major clinical outcome endpoints. In addition to detailing major challenges and statistical limitations encountered during the effort of integrating the acquired clinical data, we present a summary that includes endpoint usage recommendations for each cancer type. These TCGA-CDR findings appear to be consistent with cancer genomics studies independent of the TCGA effort and provide opportunities for investigating cancer biology using clinical correlates at an unprecedented scale. Analysis of clinicopathologic annotations for over 11,000 cancer patients in the TCGA program leads to the generation of TCGA Clinical Data Resource, which provides recommendations of clinical outcome endpoint usage for 33 cancer types
Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector
A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results
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