Demagnetization via Nucleation of the Nonequilibrium Metastable Phase in a Model of Disorder

We study both analytically and numerically metastability and nucleation in a two-dimensional nonequilibrium Ising ferromagnet. Canonical equilibrium is dynamically impeded by a weak random perturbation which models homogeneous disorder of undetermined source. We present a simple theoretical description, in perfect agreement with Monte Carlo simulations, assuming that the decay of the nonequilibrium metastable state is due, as in equilibrium, to the competition between the surface and the bulk. This suggests one to accept a nonequilibrium "free-energy" at a mesoscopic/cluster level, and it ensues a nonequilibrium "surface tension" with some peculiar low-T behavior. We illustrate the occurrence of intriguing nonequilibrium phenomena, including: (i) Noise-enhanced stabilization of nonequilibrium metastable states; (ii) reentrance of the limit of metastability under strong nonequilibrium conditions; and (iii) resonant propagation of domain walls. The cooperative behavior of our system may also be understood in terms of a Langevin equation with additive and multiplicative noises. We also studied metastability in the case of open boundaries as it may correspond to a magnetic nanoparticle. We then observe burst-like relaxation at low T, triggered by the additional surface randomness, with scale-free avalanches which closely resemble the type of relaxation reported for many complex systems. We show that this results from the superposition of many demagnetization events, each with a well- defined scale which is determined by the curvature of the domain wall at which it originates. This is an example of (apparent) scale invariance in a nonequilibrium setting which is not to be associated with any familiar kind of criticality.Comment: 26 pages, 22 figure

Can we rely on patients' reports of adverse events?

Item does not contain fulltextBACKGROUND: Evidence suggests that patients can report a variety of adverse events (AEs) not captured by traditional methods such as a chart review. Little is known, however, about whether patient reports are useful for measuring patient safety. OBJECTIVES: To examine the degree to which physician reviewers agreed that patient reports of "negative effects" constituted AEs, and to identify questionnaire items that affected reviewers' judgments. METHODS: We surveyed patients discharged from Massachusetts hospitals in 2003 to elicit information about negative effects associated with hospitalization. Physician reviewers judged whether patient-reported negative effects represented AEs, and classified the severity of the event. Likelihood ratios were calculated to assess whether patient responses to questionnaire items affected reviewers' judgments. RESULTS: Of the 2582 patients surveyed, 753 patients reported 1170 negative effects, and 71.2% of these effects were classified as AEs by physician reviewers. Negative effects most likely to be classified as AEs involved newly prescribed medications and changes to previously prescribed medications. Additional information elicited from follow-up survey questions modestly affected reviewers' classification of serious AEs. Negative effects reported by women, younger patients, those reporting better health status, and those not admitted through the emergency department were more likely to be classified as AEs. CONCLUSIONS: Many patients were able to identify care-related AEs. Patient responses to questions about the sequelae of the events provided limited additional information for physicians to use in gauging the presence and severity of the event. Patient reports complement other incident-detection methods by providing information that is credible and unavailable from other sources.1 oktober 201

A genome-wide high-complexity shRNA library screen identifies novel factors in MHC class I trafficking and degradation

Therapeutic cell differentiatio

Ribosome Profiling Reveals Pervasive Translation Outside of Annotated Protein-Coding Genes

Ribosome profiling suggests that ribosomes occupy many regions of the transcriptome thought to be noncoding, including 5′ UTRs and long noncoding RNAs (lncRNAs). Apparent ribosome footprints outside of protein-coding regions raise the possibility of artifacts unrelated to translation, particularly when they occupy multiple, overlapping open reading frames (ORFs). Here, we show hallmarks of translation in these footprints: copurification with the large ribosomal subunit, response to drugs targeting elongation, trinucleotide periodicity, and initiation at early AUGs. We develop a metric for distinguishing between 80S footprints and nonribosomal sources using footprint size distributions, which validates the vast majority of footprints outside of coding regions. We present evidence for polypeptide production beyond annotated genes, including the induction of immune responses following human cytomegalovirus (HCMV) infection. Translation is pervasive on cytosolic transcripts outside of conserved reading frames, and direct detection of this expanded universe of translated products enables efforts at understanding how cells manage and exploit its consequences

Fault-tolerant dynamic job scheduling policy

In this paper, we propose a scalable and fault-tolerant job scheduling framework for grid computing. The proposed framework loosely couples a dynamic job scheduling approach with the hybrid replications approach to schedule jobs efficiently while at the same time providing fault-tolerance. The novelty of the proposed framework is that it uses passive replication approach under high system load and active replication approach under low system loads. The switch between these two replication methods is also done dynamically and transparently