Is demagnetization an efficient optimization method?

Demagnetization, commonly employed to study ferromagnets, has been proposed as the basis for an optimization tool, a method to find the ground state of a disordered system. Here we present a detailed comparison between the ground state and the demagnetized state in the random field Ising model, combing exact results in $d=1$ and numerical solutions in $d=3$. We show that there are important differences between the two states that persist in the thermodynamic limit and thus conclude that AC demagnetization is not an efficient optimization method.Comment: 2 pages, 1 figur

Genetically similar temperate phages form coalitions with their shared host that lead to niche-specific fitness effects.

Temperate phages engage in long-term associations with their hosts that may lead to mutually beneficial interactions, of which the full extent is presently unknown. Here, we describe an environmentally relevant model system with a single host, a species of the Roseobacter clade of marine bacteria, and two genetically similar phages (ɸ-A and ɸ-D). Superinfection of a ɸ-D lysogenized strain (CB-D) with ɸ-A particles resulted in a lytic infection, prophage induction, and conversion of a subset of the host population, leading to isolation of a newly ɸ-A lysogenized strain (CB-A). Phenotypic differences, predicted to result from divergent lysogenic-lytic switch mechanisms, are evident between these lysogens, with CB-A displaying a higher incidence of spontaneous induction. Doubling times of CB-D and CB-A in liquid culture are 75 and 100 min, respectively. As cell cultures enter stationary phase, CB-A viable counts are half of CB-D. Consistent with prior evidence that cell lysis enhances biofilm formation, CB-A produces twice as much biofilm biomass as CB-D. As strains are susceptible to infection by the opposing phage type, co-culture competitions were performed to test fitness effects. When grown planktonically, CB-A outcompeted CB-D three to one. Yet, during biofilm growth, CB-D outcompeted CB-A three to one. These results suggest that genetically similar phages can have divergent influence on the competitiveness of their shared hosts in distinct environmental niches, possibly due to a complex form of phage-mediated allelopathy. These findings have implications for enhanced understanding of the eco-evolutionary dynamics of host-phage interactions that are pervasive in all ecosystems.publishedVersio

Management of febrile neutropenia: ESMO Clinical Practice Guidelines

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Threshold bounce — occupancy-dependent modulation of the discriminating threshold in silicon detectors

The front-end electronics of silicon detectors are typically designed to ensure optimal noise performance for the expected input charge. A combination of preamplifiers and shaper circuits result in a nontrivial response of the front-end to injected charge, and the magnitude of the response may be sizeable in readout windows subsequent to that in which the charge was initially injected. The modulation of the discriminator threshold due to the superposition of the front-end response across multiple readout windows is coined “threshold bounce”. In this paper, we report a measurement of threshold bounce using silicon modules built for the Phase-II Upgrade of the ATLAS detector at the Large Hadron Collider. These modules utilize ATLAS Binary Chips for their hit readout. The measurement was performed using a micro-focused 15 keV photon beam at the Diamond Light Source synchrotron. The effect of the choice of photon flux and discriminator threshold on the magnitude of the threshold bounce is studied. A Monte Carlo simulation which accounts for the front-end behaviour of the silicon modules is developed, and its predicted hit efficiency is found to be in good agreement with the measured hit efficiency

Single coronary artery from the right sinus of Valsalva

We describe a case of a single coronary artery originating from the right coronary sinus and bifurcating into the left coronary artery (LCA) and right coronary artery (RCA) in a 74-year old woman, with a non-ST elevation acute myocardial infarction (NSTEMI). Diagnosis was made by coronary angiography which ruled out stenosis, and showed normal LCA and RCA branching. The connection path of LCA, with the opposite cusp, was defined retroaortic by multislice computed tomography (CT). The variants of this coronary anomaly, together with their clinical implications and pathophysiology of acute myocardial infarction (AMI) are discussed. Multislice CT is fundamental for clinical decision making

Search for a W' boson decaying to a bottom quark and a top quark in pp collisions at sqrt(s) = 7 TeV

Results are presented from a search for a W' boson using a dataset corresponding to 5.0 inverse femtobarns of integrated luminosity collected during 2011 by the CMS experiment at the LHC in pp collisions at sqrt(s)=7 TeV. The W' boson is modeled as a heavy W boson, but different scenarios for the couplings to fermions are considered, involving both left-handed and right-handed chiral projections of the fermions, as well as an arbitrary mixture of the two. The search is performed in the decay channel W' to t b, leading to a final state signature with a single lepton (e, mu), missing transverse energy, and jets, at least one of which is tagged as a b-jet. A W' boson that couples to fermions with the same coupling constant as the W, but to the right-handed rather than left-handed chiral projections, is excluded for masses below 1.85 TeV at the 95% confidence level. For the first time using LHC data, constraints on the W' gauge coupling for a set of left- and right-handed coupling combinations have been placed. These results represent a significant improvement over previously published limits.Comment: Submitted to Physics Letters B. Replaced with version publishe

Search for the standard model Higgs boson decaying into two photons in pp collisions at sqrt(s)=7 TeV

A search for a Higgs boson decaying into two photons is described. The analysis is performed using a dataset recorded by the CMS experiment at the LHC from pp collisions at a centre-of-mass energy of 7 TeV, which corresponds to an integrated luminosity of 4.8 inverse femtobarns. Limits are set on the cross section of the standard model Higgs boson decaying to two photons. The expected exclusion limit at 95% confidence level is between 1.4 and 2.4 times the standard model cross section in the mass range between 110 and 150 GeV. The analysis of the data excludes, at 95% confidence level, the standard model Higgs boson decaying into two photons in the mass range 128 to 132 GeV. The largest excess of events above the expected standard model background is observed for a Higgs boson mass hypothesis of 124 GeV with a local significance of 3.1 sigma. The global significance of observing an excess with a local significance greater than 3.1 sigma anywhere in the search range 110-150 GeV is estimated to be 1.8 sigma. More data are required to ascertain the origin of this excess.Comment: Submitted to Physics Letters