Case study : a patient-clinician collaboration that identified and prioritized evidence gaps and stimulated research development

Copyright © 2013 Elsevier Inc. All rights reserved.Peer reviewedPostprin

Antiphase dynamics in a multimode semiconductor laser with optical injection

A detailed experimental study of antiphase dynamics in a two-mode semiconductor laser with optical injection is presented. The device is a specially designed Fabry-Perot laser that supports two primary modes with a THz frequency spacing. Injection in one of the primary modes of the device leads to a rich variety of single and two-mode dynamical scenarios, which are reproduced with remarkable accuracy by a four dimensional rate equation model. Numerical bifurcation analysis reveals the importance of torus bifurcations in mediating transitions to antiphase dynamics and of saddle-node of limit cycle bifurcations in switching of the dynamics between single and two-mode regimes.Comment: 7 pages, 9 figure

A gamma-ray burst remnant in our Galaxy: HESS J1303-631

We present the results of our investigation of the multiwavelength data on HESS J1303-631, an unidentified TeV source serendipitously discovered in the Galactic plane by the HESS collaboration. These results strongly suggest the identification of this particular source as the remnant of a Gamma-Ray Burst (GRB) that happened some few tens of thousands years ago in our Galaxy at a distance on the order of 10 kpc from us. We show, through detailed calculations of particle diffusion, interaction and radiation processes of relativistic particles in the interstellar medium, that it is possible for a GRB remnant (GRBR) to be a strong TeV emitter with no observable synchrotron emission. We predict spectral and spatial signatures that would unambiguously distinguish GRBRs from ordinary supernova remnants, including: (1) large energy budgets inferred from their TeV emission, but at the same time, (2) suppressed fluxes in the radio through GeV wavebands; (3) extended center-filled emission with an energy-dependent spatial profile; and (4) a possible elongation in the direction of the past pair of GRB jets. While GRBRs can best be detected by ground-based gamma-ray detectors, the future GLAST mission will play a crucial role in confirming the predicted low level of GeV emission.Comment: Replaced by the version accepted in ApJ Letters (to appear in April/May 2006); 4 pages, 3 figure

Replication enhancer elements within the open reading frame of tick-borne encephalitis virus and their evolution within the Flavivirus genus

We provide experimental evidence of a replication enhancer element (REE) within the capsid gene of tick-borne encephalitis virus (TBEV, genus Flavivirus). Thermodynamic and phylogenetic analyses predicted that the REE folds as a long stable stem–loop (designated SL6), conserved among all tick-borne flaviviruses (TBFV). Homologous sequences and potential base pairing were found in the corresponding regions of mosquito-borne flaviviruses, but not in more genetically distant flaviviruses. To investigate the role of SL6, nucleotide substitutions were introduced which changed a conserved hexanucleotide motif, the conformation of the terminal loop and the base-paired dsRNA stacking. Substitutions were made within a TBEV reverse genetic system and recovered mutants were compared for plaque morphology, single-step replication kinetics and cytopathic effect. The greatest phenotypic changes were observed in mutants with a destabilized stem. Point mutations in the conserved hexanucleotide motif of the terminal loop caused moderate virus attenuation. However, all mutants eventually reached the titre of wild-type virus late post-infection. Thus, although not essential for growth in tissue culture, the SL6 REE acts to up-regulate virus replication. We hypothesize that this modulatory role may be important for TBEV survival in nature, where the virus circulates by non-viraemic transmission between infected and non-infected ticks, during co-feeding on local rodents

Highly Variable Acquisition Rates of \u3ci\u3eIxodes scapularis\u3c/i\u3e (Acari: Ixodidae) by Birds on an Atlantic Barrier Island

Acquisition of ticks by bird hosts is a central process in the transmission cycles of many tick-borne zoonoses, but tick recruitment by birds has received little direct study. We documented acquisition of Ixodes scapularis Say on birds at Fire Island, NY, by removing ticks from mist-netted birds, and recording the number of ticks on birds recaptured within 4 d of release. Eight bird species acquired at least 0.8 ticks bird−1 day−1 during the seasonal peak for at least one age class of I. scapularis. Gray Catbirds, Eastern Towhees, Common Yellowthroats, and Northern Waterthrushes collectively accounted for 83% of all tick acquisitions; and six individuals apportioned among Black-billed Cuckoo, Gray Catbird, Eastern Towhee, and Common Yellowthroat were simultaneously infested with both larvae and nymphs. Bird species with the highest acquisition rates were generally ground foragers, whereas birds that did not acquire ticks in our samples generally foraged above the ground. Tick acquisition by birds did not differ between deciduous and coniferous forests. Among the 15 bird species with the highest recruitment rates, acquisition of nymphs was not correlated with acquisition of larvae. Tick acquisition rates by individual bird species were not correlated with the reservoir competence of those species for Lyme borreliae. However, birds with high tick acquisition rates can contribute large numbers of infected ticks, and thus help maintain the enzootic cycle, even if their levels of reservoir competence are relatively low

Pfaffian representations of cubic surfaces

Let K be a field of characteristic zero. We describe an algorithm which requires a homogeneous polynomial F of degree three in K[x_0,x_1,x_2,x_3] and a zero A of F in P^3_K and ensures a linear pfaffian representation of V(F) with entries in K[x_0,x_1,x_2,x_3], under mild assumptions on F and A. We use this result to give an explicit construction of (and to prove the existence of) a linear pfaffian representation of V(F), with entries in K'[x_0,x_1,x_2,x_3], being K' an algebraic extension of K of degree at most six. An explicit example of such a construction is given.Comment: 17 pages. Expanded with some remarks. Published with minor corrections in Geom. Dedicat

Optical studies of two LMC X-ray transients : RX J0544.1-7100 and RX J0520.5-6932

We report observations which confirm the identities of the optical counterpart to the transient sources RX J0544.1-7100 and RX J0520.5-6932. The counterparts are suggested to be a B-type stars. Optical data from the observations carried out at ESO and SAAO, together with results from the OGLE data base, are presented. In addition, X-ray data from the RXTE all-sky monitor are investigated for long term periodicities. A strong suggestion for a binary period of 24.4d is seen in RX J0520.5-6932 from the OGLE data.Comment: 6 pages, 7 figure

The estimation of neutrino fluxes produced by proton-proton collisions at s=14\sqrt{s}=14 TeV of the LHC

Intense and collimated neutrino beams are produced by charm and beauty particle decays from proton-proton collisions at the LHC. A neutrino experiment would be run parasitically without interrupting the LHC physics program during the collider run. We estimate the neutrino fluxes from proton-proton collisions at $\sqrt{s}=14$ TeV of the LHC with the designed luminosity, 10^{34} \lumi. By mounting about 200 tons of fiducial volume of a neutrino detector at 300 \m away from the interaction point, about 150,000 of charged current neutrino events per year can be observable.Comment: 8 pages, Accepted in JHE