Design of an RSFQ Control Circuit to Observe MQC on an rf-SQUID

We believe that the best chance to observe macroscopic quantum coherence (MQC) in a rf-SQUID qubit is to use on-chip RSFQ digital circuits for preparing, evolving and reading out the qubit's quantum state. This approach allows experiments to be conducted on a very short time scale (sub-nanosecond) without the use of large bandwidth control lines that would couple environmental degrees of freedom to the qubit thus contributing to its decoherence. In this paper we present our design of a RSFQ digital control circuit for demonstrating MQC in a rf-SQUID. We assess some of the key practical issues in the circuit design including the achievement of the necessary flux bias stability. We present an "active" isolation structure to be used to increase coherence times. The structure decouples the SQUID from external degrees of freedom, and then couples it to the output measurement circuitry when required, all under the active control of RSFQ circuits. Research supported in part by ARO grant # DAAG55-98-1-0367.Comment: 4 pages. More information and publications at http://www.ece.rochester.edu:8080/users/sde/research/publications/index.htm

IR characterization of Ln2−xSrxCoO4 (x≥1; Ln=La, Nd) oxides

[Abstract] We have recorded the FTIR spectra of powder samples of Ln2−xSrxCoO4 (Ln=La, Nd) at room temperature. We have identified the infrared active modes (3A2u+4Eu), and analyzed how they change as a function of Ln and the Sr doping. We correlate the obtained results with structural data obtained from powder X-ray diffraction studies and with the electronic properties displayed by these samples

Investigating the retention of intermediate-mass black holes in star clusters using N-body simulations

Contrary to supermassive and stellar-mass black holes (SBHs), the existence of intermediate-mass black holes (IMBHs) with masses ranging between 10^{2-5} Msun has not yet been confirmed. The main problem in the detection is that the innermost stellar kinematics of globular clusters (GCs) or small galaxies, the possible natural loci to IMBHs, are very difficult to resolve. However, if IMBHs reside in the centre of GCs, a possibility is that they interact dynamically with their environment. A binary formed with the IMBH and a compact object of the GC would naturally lead to a prominent source of gravitational radiation, detectable with future observatories. We use N-body simulations to study the evolution of GCs containing an IMBH and calculate the gravitational radiation emitted from dynamically formed IMBH-SBH binaries and the possibility that the IMBH escapes the GC after an IMBH-SBH merger. We run for the first time direct-summation integrations of GCs with an IMBH including the dynamical evolution of the IMBH with the stellar system and relativistic effects, such as energy loss in gravitational waves (GWs) and periapsis shift, and gravitational recoil. We find in one of our models an intermediate mass-ratio inspiral (IMRI), which leads to a merger with a recoiling velocity higher than the escape velocity of the GC. The GWs emitted fall in the range of frequencies that a LISA-like observatory could detect, like the European eLISA or in mission options considered in the recent preliminary mission study conducted in China. The merger has an impact on the global dynamics of the cluster, as an important heating source is removed when the merged system leaves the GC. The detection of one IMRI would constitute a test of GR, as well as an irrefutable proof of the existence of IMBHs.Comment: Accepted for publication by A&A, minor modification

Ultrafast Pulse Radiolysis Using a Terawatt Laser Wakefield Accelerator

We report the first ultrafast pulse radiolysis transient absorption spectroscopy measurements from the Terawatt Ultrafast High Field Facility (TUHFF) at Argonne National Laboratory. TUHFF houses a 20 TW Ti:sapphire laser system that generates 2.5 nC sub-picosecond pulses of multi-MeV electrons at 10 Hz using laser wakefield acceleration. The system has been specifically optimized for kinetic measurements in a pump-probe fashion. This requires averaging over many shots which necessitates stable, reliable generation of electron pulses. The latter were used to generate excess electrons in pulse radiolysis of liquid water and concentrated solutions of perchloric acid. The hydronium ions in the acidic solutions react with the hydrated electrons resulting in the rapid decay of the transient absorbance at 800 nm on the picosecond time scale. Time resolution of a few picoseconds has been demonstrated. The current time resolution is determined primarily by the physical dimensions of the sample and the detection sensitivity. Subpicosecond time resolution can be achieved by using thinner samples, more sensitive detection techniques and improved electron beam quality.Comment: submitted to J. Appl. Phys. 5 figures, 23 page

Investigating the impact of poverty on colonization and infection with drug-resistant organisms in humans: a systematic review

Background Poverty increases the risk of contracting infectious diseases and therefore exposure to antibiotics. Yet there is lacking evidence on the relationship between income and non-income dimensions of poverty and antimicrobial resistance. Investigating such relationship would strengthen antimicrobial stewardship interventions. Methods A systematic review was conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. PubMed, Ovid, MEDLINE, EMBASE, Scopus, CINAHL, PsychINFO, EBSCO, HMIC, and Web of Science databases were searched in October 2016. Prospective and retrospective studies reporting on income or non-income dimensions of poverty and their influence on colonisation or infection with antimicrobial-resistant organisms were retrieved. Study quality was assessed with the Integrated quality criteria for review of multiple study designs (ICROMS) tool. Results Nineteen articles were reviewed. Crowding and homelessness were associated with antimicrobial resistance in community and hospital patients. In high-income countries, low income was associated with Streptococcus pneumoniae and Acinetobacter baumannii resistance and a seven-fold higher infection rate. In low-income countries the findings on this relation were contradictory. Lack of education was linked to resistant S. pneumoniae and Escherichia coli. Two papers explored the relation between water and sanitation and antimicrobial resistance in low-income settings. Conclusions Despite methodological limitations, the results suggest that addressing social determinants of poverty worldwide remains a crucial yet neglected step towards preventing antimicrobial resistance

Factors influencing erythrocyte sedimentation rate in adults New evidence for an old test

The erythrocyte sedimentation rate (ESR) is a routine test for inflammation. Few studies have investigated the potential influence of lifestyle factors and common metabolic abnormalities on the ESR. This study investigates the influence of demographic factors, alcohol consumption, smoking, physical activity, obesity, and metabolic syndrome on the ESR in adults.This cross-sectional study covered 1472 individuals (44.5% males; age range, 18-91 years) randomly selected from the population of a Spanish municipality. The ESR was measured using a standardized method. We assessed habitual alcohol consumption in standard drinking units, along with tobacco smoking, regular physical exercise (by questionnaire), body mass index, and variables defining metabolic syndrome. Multivariate analyses were performed, including mean corpuscular volume and hemoglobin concentration in the models.The ESR was higher in females than in males, and increased steadily with age. Median ESR of females was 2-fold higher than that of males, and median ESR of individuals aged >65 years was 2-fold higher than that of individuals in the youngest category (ages 18-35 years). Body mass index, presence of metabolic syndrome, and smoking were independently and positively associated with higher ESR values. Light alcohol drinkers and individuals with high regular physical activity displayed lower ESR values than did alcohol abstainers and individuals with low physical activity, respectively.ESR varies greatly with age and sex, and corresponding reference values are proposed. Lifestyle factors (physical activity, smoking, and alcohol consumption) and common metabolic abnormalities (obesity and related metabolic syndrome) may also influence ESR values

Adiabatic evolution of a coupled-qubit Hamiltonian

We present a general method for studying coupled qubits driven by adiabatically changing external parameters. Extended calculations are provided for a two-bit Hamiltonian whose eigenstates can be used as logical states for a quantum CNOT gate. From a numerical analysis of the stationary Schroedinger equation we find a set of parameters suitable for representing CNOT, while from a time-dependent study the conditions for adiabatic evolution are determined. Specializing to a concrete physical system involving SQUIDs, we determine reasonable parameters for experimental purposes. The dissipation for SQUIDs is discussed by fitting experimental data. The low dissipation obtained supports the idea that adiabatic operations could be performed on a time scale shorter than the decoherence time.Comment: 10 pages, 4 figures, to be pub.in Phys Rev

Second-Order Formalism for 3D Spin-3 Gravity

A second-order formalism for the theory of 3D spin-3 gravity is considered. Such a formalism is obtained by solving the torsion-free condition for the spin connection \omega^a_{\mu}, and substituting the result into the action integral. In the first-order formalism of the spin-3 gravity defined in terms of SL(3,R) X SL(3,R) Chern-Simons (CS) theory, however, the generalized torsion-free condition cannot be easily solved for the spin connection, because the vielbein e^a_{\mu} itself is not invertible. To circumvent this problem, extra vielbein-like fields e^a_{\mu\nu} are introduced as a functional of e^a_{\mu}. New set of affine-like connections \Gamma_{\mu M}^N are defined in terms of the metric-like fields, and a generalization of the Riemann curvature tensor is also presented. In terms of this generalized Riemann tensor the action integral in the second-order formalism is expressed. The transformation rules of the metric and the spin-3 gauge field under the generalized diffeomorphims are obtained explicitly. As in Einstein gravity, the new affine-like connections are related to the spin connection by a certain gauge transformation, and a gravitational CS term expressed in terms of the new connections is also presented.Comment: 40 pages, no figures. v2:references added, coefficients of eqs in apppendix D corrected, minor typos also corrected, v3:Version accepted for publication in Classical and Quantum Gravit

Tendências genéticas e fenotípicas para características indicadoras de eficiência reprodutiva em bovinos da Raça Nelore sob seleção para precocidade sexual.

Resumo: As características reprodutivas estão diretamente relacionadas à eficiência econômica dos sistemas de produção de bovinos de corte. Assim, objetivou-se com este estudo estimar as tendências genéticas e fenotípicas entre características de reprodução e idade à primeira concepção e ao primeiro parto, em um rebanho Nelore sob seleção para precocidade sexual. Os componentes de (co)variância foram obtidos utilizando-se o método de Máxima Verossimilhança Restrita, disponível no pacote BLUPF90, em análises uni e bicaracterísticas, sob modelo animal. Para o cálculo das tendências genéticas através da regressão foram utilizados os valores genéticos anuais médios em relação ao ano de nascimento pelo PROC REG do SAS, seguindo tendência linear e quadrática. E a tendência fenotípica da população usando os valores fenotípicos. As tendências genéticas foram -0,03 dias/ano para PS, -0,14 dias/ano para IDP, -0,12 meses/ano para IPC e -0,16 meses/ano para IPP. A seleção para precocidade sexual, tendo como critério de seleção IPC ou IPP, promoverá melhoria na eficiência reprodutiva e fertilidade do rebanho. Abstract: The reproductive traits are directly related to the economic efficiency of beef cattle production systems. Thus, the aim of this study was to estimate the genetic parameters and the genetic and phenotypic trends for reproductive traits and age at first conception and first calving in a Nellore cattle herd under selection for sexual precocity. The covariance components were estimated using the Restricted Maximum Likelihood method, available on BLUPF90 package, in univariate and bivariate analyzes using animal model. For the calculation of the genetic trends through the regression the PROC REG of the SAS, following a linear and quadratic tendency used the average annual genetic values in relation to the year of birth. The phenotypic trend of the population using the phenotypic values. The genetic trends were -0.03 days/year for DO, -0.14 days/year for CI, -0.12 months /year for AFCo and -0.16 months/year for AFCa. Selection for sexual precocity based on AFCo and AFCa shall promote improvement in reproductive efficiency and fertility

Parâmetros genéticos para características de composição de carcaça em bovinos da raça Nelore sob seleção para precocidade sexual.

Resumo: Objetivou-se, com este estudo, estimar os parâmetros genéticos para características de composição de carcaça e idade à primeira concepção (IPC) e ao primeiro parto (IPP), em um rebanho da raça Nelore sob seleção para precocidade sexual. Foram estimados os parâmetros genéticos para as características peso da caraça quente (PCQ), peso da porção comestível (PPC), IPC e IPP. Os componentes de (co)variância foram obtidos pelo método de Máxima Verossimilhança Restrita, disponível no pacote BLUPF90, em análises uni e bicaracterísticas, utilizando o modelo animal. As estimativas de herdabilidade foram de 0,39 (PCQ), 0,39 (PPC), 0,21 (IPC) e 0,24 (IPP). As características indicadoras de precocidade sexual apresentaram coeficientes de correlação genética entre -0,45 a -0,40 com as características de composição frigorífica. A seleção para precocidade sexual com base na idade à primeira concepção deverá promover mudanças genéticas no sentido contrário na s características de composição de carcaça. Abstract: The aim of this study was to estimate the genetic parameters carcass composition traits and age at first conception (AFCo) and first calving (AFCa), in a Nellore cattle herd under selection for sexual precocity. Genetic parameters were estimated for hot carcass weight (HCW), weight of edible portion (WEP), AFCo and AFCa. The covariance components were estimated using the Restricted Maximum Likelihood method, available on BLUPF90 package, in univariate and bivariate analyzes using animal model. The heritability estimated for 0.39 (HCW), 0.39 (WEP), 0.21 (AFCo) and 0.24 (AFCa). The traits that indicate sexual precocity showed genetic correlation coefficients ranging from -0.45 to -0.40 with carcass composition traits, respectively. Selection for sexual precocity based on age the first conception shall promote opposite direction genetic changes on carcass composition traits