Corticothalamic projections control synchronization in locally coupled bistable thalamic oscillators

Thalamic circuits are able to generate state-dependent oscillations of different frequencies and degrees of synchronization. However, only little is known how synchronous oscillations, like spindle oscillations in the thalamus, are organized in the intact brain. Experimental findings suggest that the simultaneous occurrence of spindle oscillations over widespread territories of the thalamus is due to the corticothalamic projections, as the synchrony is lost in the decorticated thalamus. Here we study the influence of corticothalamic projections on the synchrony in a thalamic network, and uncover the underlying control mechanism, leading to a control method which is applicable in wide range of stochastic driven excitable units.Comment: 4 pages with 4 figures (Color online on p.3-4) include

Relative amplitude index: A new tool for hemodynamic evaluation of periprosthetic regurgitation after transcatheter valve implantation

ObjectiveThe impact of paravalvular aortic regurgitation (PAR) on hemodynamic performance after transcatheter aortic valve implantation (TAVI) remains disputable. Common parameters such as the diastolic blood pressure or the blood pressure amplitude do not provide reproducible results. The aim of our study was to evaluate the impact of PAR on hemodynamics and outcome using the relative amplitude index (RAI).MethodsPAR was prospectively evaluated by echocardiography before discharge in 110 patients. The RAI was calculated according to the formula: RAI = [(Post-TAVI BP amplitude)/(Post-TAVI SBP) − (Pre-TAVI BP amplitude)/(Pre-TAVI SBP)] × 100%, where BP is blood pressure and SBP is systolic blood pressure. Correlations of increased RAI with perioperative outcome were investigated and factors influencing mortality were isolated.ResultsThe incidence of moderate and severe PAR after TAVI was 9% and 1%, respectively. Diastolic pressure or post-TAVI amplitude did not correlate to perioperative outcome. RAI increased from 2 when PAR was <2+ to 7 when PAR was ≥2+ (P = .006). A cut-off value of RAI ≥14 was associated with increased perioperative mortality (29 vs 5%; P = .013) and acute renal injury requiring dialysis (71 vs 18%; P = .001). RAI ≥14 was also associated with higher follow-up mortality at 1 year (57 vs 16%; P = .007). RAI ≥14 (odds ratio [OR], 3.390; 95% confidence interval [CI], 1.6-7.194; P = .00146), PAR ≥2+ (OR, 4.717; 95% CI, 1.828-12.195; P = .00135), and perioperative renal replacement therapy (OR, 12.820; 95% CI, 5.181-31.250; P = .00031) were found to be independent predictors of mortality at 1 year.ConclusionsThe RAI is a useful tool to predict perioperative and 1-year outcome in patients with PAR after TAVI

Variable Electron-Phonon Coupling in Isolated Metallic Carbon Nanotubes Observed by Raman Scattering

We report the existence of broad and weakly asymmetric features in the high-energy (G) Raman modes of freely suspended metallic carbon nanotubes of defined chiral index. A significant variation in peak width (from 12 cm-1 to 110 cm-1) is observed as a function of the nanotube's chiral structure. When the nanotubes are electrostatically gated, the peak widths decrease. The broadness of the Raman features is understood as the consequence of coupling of the phonon to electron-hole pairs, the strength of which varies with the nanotube chiral index and the position of the Fermi energy.Comment: 13 pages; submitted to Phys. Rev. Let

The QCD thermal phase transition in the presence of a small chemical potential

We propose a new method to investigate the thermal properties of QCD with a small quark chemical potential $\mu$. Derivatives of the phase transition point with respect to $\mu$ are computed at $\mu=0$ for 2 flavors of p-4 improved staggered fermions with $ma=0.1,0.2$ on a $16^3\times4$ lattice. The resulting Taylor expansion is well behaved for the small values of $\mu_{\rm q}/T_c\sim0.1$ relevant for RHIC phenomenology, and predicts a critical curve $T_c(\mu)$ in reasonable agreement with estimates obtained using exact reweighting. In addition, we contrast the case of isoscalar and isovector chemical potentials, quantify the effect of $\mu\not=0$ on the equation of state, and comment on the complex phase of the fermion determinant in QCD with $\mu\not=0$.Comment: 26 pages, 25 figures, minor modificatio

Peripheral heavy ion collisions as a probe of the nuclear gluon distribution

At high energies a quark-gluon plasma is expected to be formed in heavy ion collisions at RHIC and LHC. The theoretical description of these processes is directly associated to a complete knowledge of the details of medium effects in the nuclear gluon distribution. In this paper we analyze the possibility to constraint the behavior of this distribution considering peripheral heavy ion collisions. We reanalyze the photoproduction of heavy quarks for the deduction of the in-medium gluon distribution using three current parameterizations for this parton distribution. Moreover, we show that the elastic photoproduction of vector mesons is a potential process to probe the nuclear gluon distribution.Comment: 8 figures, accepted for publication in Physicsl review

Relativistic Nucleus-Nucleus Collisions: from the BEVALAC to RHIC

I briefly describe the initial goals of relativistic nuclear collisions research, focusing on the LBL Bevatron/Bevalac facility in the 1970's. An early concept of high hadronic density fireball formation, and subsequent isentropic decay (preserving information as to the high density stage) led to an outline of physics observables that could determine the nuclear matter equation of state at several times nuclear ground state matter density. With the advent of QCD the goal of locating, and characterizing the hadron-parton deconfinement phase transformation suggested the need for higher $\sqrt{s}$, the research thus moving to the BNL AGS and CERN SPS, finally to RHIC at BNL. A set of physics observables is discussed where present data span the entire $\sqrt{s}$ domain, from Bevalac and SIS at GSI, to top RHIC energy. Referring, selectively, to data concerning bulk hadron production, the overall $\sqrt{s}$ evolution of directed and radial flow observables, and of pion pair Bose-Einstein correlation are discussed. The hadronization process is studied in the grand canonical statistical model. The resulting hadronization points in the plane T vs. $\mu_B$ converge onto the parton-hadron phase boundary predicted by finite $\mu_B$ lattice QCD, from top SPS to RHIC energy. At lower SPS and top AGS energy a steep strangeness maximum occurs at which the Wroblewski parameter $\lambda_s \approx$ 0.6; a possible connection to the QCD critical point is discussed. Finally the unique new RHIC physics is addressed: high $p_T$ hadron suppression and jet "tomography".Comment: 19 pages, 11 figure

Early and Middle Holocene Hunter-Gatherer Occupations in Western Amazonia: The Hidden Shell Middens

We report on previously unknown early archaeological sites in the Bolivian lowlands, demonstrating for the first time early and middle Holocene human presence in western Amazonia. Multidisciplinary research in forest islands situated in seasonally-inundated savannahs has revealed stratified shell middens produced by human foragers as early as 10,000 years ago, making them the oldest archaeological sites in the region. The absence of stone resources and partial burial by recent alluvial sediments has meant that these kinds of deposits have, until now, remained unidentified. We conducted core sampling, archaeological excavations and an interdisciplinary study of the stratigraphy and recovered materials from three shell midden mounds. Based on multiple lines of evidence, including radiocarbon dating, sedimentary proxies (elements, steroids and black carbon), micromorphology and faunal analysis, we demonstrate the anthropogenic origin and antiquity of these sites. In a tropical and geomorphologically active landscape often considered challenging both for early human occupation and for the preservation of hunter-gatherer sites, the newly discovered shell middens provide evidence for early to middle Holocene occupation and illustrate the potential for identifying and interpreting early open-air archaeological sites in western Amazonia. The existence of early hunter-gatherer sites in the Bolivian lowlands sheds new light on the region's past and offers a new context within which the late Holocene "Earthmovers" of the Llanos de Moxos could have emerged. © 2013 Lombardo et al

International Veterinary Epilepsy Task Force Consensus Proposal: Outcome of therapeutic interventions in canine and feline epilepsy

Common criteria for the diagnosis of drug resistance and the assessment of outcome are needed urgently as a prerequisite for standardized evaluation and reporting of individual therapeutic responses in canine epilepsy. Thus, we provide a proposal for the definition of drug resistance and partial therapeutic success in canine patients with epilepsy. This consensus statement also suggests a list of factors and aspects of outcome, which should be considered in addition to the impact on seizures. Moreover, these expert recommendations discuss criteria which determine the validity and informative value of a therapeutic trial in an individual patient and also suggest the application of individual outcome criteria. Agreement on common guidelines does not only render a basis for future optimization of individual patient management, but is also a presupposition for the design and implementation of clinical studies with highly standardized inclusion and exclusion criteria. Respective standardization will improve the comparability of findings from different studies and renders an improved basis for multicenter studies. Therefore, this proposal provides an in-depth discussion of the implications of outcome criteria for clinical studies. In particular ethical aspects and the different options for study design and application of individual patient-centered outcome criteria are considered

Signatures of Quark-Gluon-Plasma formation in high energy heavy-ion collisions: A critical review

A critical review on signatures of Quark-Gluon-Plasma formation is given and the current (1998) experimental status is discussed. After giving an introduction to the properties of QCD matter in both, equilibrium- and non-equilibrium theories, we focus on observables which may yield experimental evidence for QGP formation. For each individual observable the discussion is divided into three sections: first the connection between the respective observable and QGP formation in terms of the underlying theoretical concepts is given, then the relevant experimental results are reviewed and finally the current status concerning the interpretation of both, theory and experiment, is discussed. A comprehensive summary including an outlook towards RHIC is given in the final section.Comment: Topical review, submitted to Journal of Physics G: 68 pages, including 39 figures (revised version: only minor modifications, some references added

Evidence of Bordetella pertussis infection in vaccinated 1-year-old Danish children

We measured IgA and IgG antibodies to pertussis toxin (PT) and filamentous hemagglutinin (FHA) in sera from 203 1-year-old children who had received one to three doses of a monocomponent PT toxoid vaccine. Ten children (5%) had IgA antibody to PT indicating recent infection; seven of these children had received three doses of vaccine. PT IgA responders did not have significantly longer coughing episodes than PT IgA non-responders. Since an IgA antibody response occurs in only ∼50% of infected children, the actual infection rate in our cohort is estimated to ∼10%. The apparent high Bordetella pertussis infection rate in Danish infants suggests that the monocomponent PT toxoid vaccine used in Denmark has limited efficacy against B. pertussis infection. A prospective immunization study comparing a multi-component vaccine with the present monocomponent PT toxoid vaccine should be undertaken