39 research outputs found

    Optimum electrode configurations for fast ion separation in microfabricated surface ion traps

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    For many quantum information implementations with trapped ions, effective shuttling operations are important. Here we discuss the efficient separation and recombination of ions in surface ion trap geometries. The maximum speed of separation and recombination of trapped ions for adiabatic shuttling operations depends on the secular frequencies the trapped ion experiences in the process. Higher secular frequencies during the transportation processes can be achieved by optimising trap geometries. We show how two different arrangements of segmented static potential electrodes in surface ion traps can be optimised for fast ion separation or recombination processes. We also solve the equations of motion for the ion dynamics during the separation process and illustrate important considerations that need to be taken into account to make the process adiabatic

    A genetic investigation of sex bias in the prevalence of attention-deficit/hyperactivity disorder

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    Background Attention-deficit/hyperactivity disorder (ADHD) shows substantial heritability and is 2-7 times more common in males than females. We examined two putative genetic mechanisms underlying this sex bias: sex-specific heterogeneity and higher burden of risk in female cases. Methods We analyzed genome-wide autosomal common variants from the Psychiatric Genomics Consortium and iPSYCH Project (20,183 cases, 35,191 controls) and Swedish populationregister data (N=77,905 cases, N=1,874,637 population controls). Results Genetic correlation analyses using two methods suggested near complete sharing of common variant effects across sexes, with rg estimates close to 1. Analyses of population data, however, indicated that females with ADHD may be at especially high risk of certain comorbid developmental conditions (i.e. autism spectrum disorder and congenital malformations), potentially indicating some clinical and etiological heterogeneity. Polygenic risk score (PRS) analysis did not support a higher burden of ADHD common risk variants in female cases (OR=1.02 [0.98-1.06], p=0.28). In contrast, epidemiological sibling analyses revealed that the siblings of females with ADHD are at higher familial risk of ADHD than siblings of affected males (OR=1.14, [95% CI: 1.11-1.18], p=1.5E-15). Conclusions Overall, this study supports a greater familial burden of risk in females with ADHD and some clinical and etiological heterogeneity, based on epidemiological analyses. However, molecular genetic analyses suggest that autosomal common variants largely do not explain the sex bias in ADHD prevalence

    Transmit Antenna Selection for UHF MIMO Linking

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    The use of multiple-input multiple-output (MIMO) configurations in wireless systems is becoming increasingly popular, due to the potential capacity enhancing properties. The use of such configurations, requires deployment of multiple RF chains and results in an increase in cost and complexity. This paper focuses on transmitter design, where cost is often dominated by the need to utilise linearized power amplifiers. Thus, the effect of reducing the number of active transmit antennae through selection can yield a significant cost advantage. Three criteria for transmit antenna selection are evaluated and characterised through the use of real channel data in the UHF band. The criteria are based only on the channel gains and have relatively low complexity; thus are suitable for practical purposes. This study examines the performance of the tested selection algorithms under a variety of operating conditions. The paper also considers the issue of delayed switch time due to reverse-link communication latenc

    Maintaining alignment over the long-term: lessons from the evolution of an electronic point of sale system

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    Research in both the organizational and information systems areas suggests that aligning information systems and dimensions of the organization improves performance. However, the dynamic nature of both information systems and organizations makes a close alignment more an aspiration than a state. This paper examines alignment from the perspective of the management processes through which companies may achieve and sustain alignment in dynamic environments. In so doing they may also develop core capabilities in managing IS innovation, which enable sustained competitive advantage. The paper traces the evolution of alignment in a company that used information systems to develop the business in new strategic directions, and shows how semi-structures contributed to this

    Botulismo em bovinos de corte e leite alimentados com cama de frango Botulism in beef and dairy cattle fed with poultry litter

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    Surtos de botulismo causados pelos tipos C e D da toxina botulínica são freqüentes no país, estando originalmente associados à osteofagia e à ingestão de alimentos e água contaminados. No presente trabalho são descritos os aspectos epidemiológicos, clínico-patológicos e laboratoriais de sete surtos da intoxicação em bovinos de corte e leite alimentados com cama de frango, ocorridos nos estados de São Paulo e Minas Gerais entre 1989 e 2000. Cinco surtos ocorreram em rebanhos de corte confinados ou criados extensivamente e suplementados com o subproduto, e dois em propriedades leiteiras. De um total de 1.535 animais alimentados regularmente com a cama de frango, 455 (29,64%) morreram em um período que variou de 2 a 4 semanas. A morbidade nos sete surtos estudados variou de 3,47 a 100%, da mesma forma que a mortalidade. Em uma das propriedades a letalidade foi de 60,52%, e em todos os outros surtos ela foi acima de 88,43%; em três propriedades o coeficiente foi de 100%. Os sinais clínicos de paralisia progressiva, dificuldade na locomoção, decúbito e estado mental aparentemente normal, diminuição do tônus da musculatura da língua e cauda, sialorréia e dificuldade respiratória caracterizaram o quadro clínico. À necropsia de 30 animais não foi observada qualquer alteração macroscópica digna de nota. A presença de esporos de Clostridium botulinum foi detectada em amostras de cama de frango colhidas nas sete propriedades. Nas amostras de fígado, líquido ruminal e intestinal, provenientes dos 30 animais necropsiados, foi possível detectar toxinas botulínicas tipos C (5) ou D (9), ou classificada como pertencente ao complexo CD (1), em pelos menos um dos materiais provenientes de 15 animais, confirmando assim o diagnóstico clínico-patológico e epidemiológico de botulismo.<br>Outbreaks of botulism caused by type C and D of the botulinum toxin are frequent in Brazil, and are associated with bone chewing and ingestion of contaminated food and water. This paper reports the epidemiological, clinical, pathological and laboratorial aspects of 7 outbreaks of botulism in beef and dairy cattle fed with poultry litter, which occurred in the states of São Paulo and Minas Gerais, 1989-2000. Five outbreaks occurred in beef cattle herds, raised in confinement or under pasture conditions and supplemented with poultry litter, and 2 outbreaks occurred in dairy farms. From o total of 1,535 cattle supplemented regularily with poultry litter 455 animals (29.64%) died within 2 to 4 weeks. Morbidity and mortality varied from 3.47 to 100% in the 7 outbreaks. In one of the farms the lethality was 60.52%, and in others more than 88.43%, reaching 100% in three farms. Clinical signs were progressive paralysis, difficulties in moving, decubitus, normal alertness, decreased muscular tonus of tongue and tail, sialorrhoe and dyspnoe. At post-mortem examination of 30 cattle no noteable changes were observed. Spores of Clostridium botulinum were found in poultry litter samples collected on 7 farms. In liver, ruminal and intestinal fluid samples from 30 necropsied cattle botulinum toxin of type C (5) and D (9) or of the CD complex (1) were found in at least one of the samples collected from 15 animals, which confirms the clincial, pathological and epidemiological diagnosis of botulism
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