8,731 research outputs found

    The coexistence of pressure waves in the operation of quartz-crystal shear-wave sensors

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    It is demonstrated that an AT-cut quartz crystal driven in the thickness-shear-wave mode and typically used as a sensor to monitor the viscoelastic shear-wave properties of a fluid also produce longitudinal pressure waves. Unlike the shear wave, these waves are capable of long-range propagation through the fluid and of reflection at its boundaries, notably at an outer fluid–air interface. They introduce a component into the measured electrical impedance and resonance frequency shift of the crystal, which reflects the setting up of cyclic pressure-wave resonances in the fluid. This has important implications for the practical employment of these crystal as sensors. Under appropriate conditions, as demonstrated for water and n-octane, it is possible to determine the propagating properties of sound waves in a fluid simultaneously with the viscoelastic shear-wave properties. These experiments are supported by an analysis of the appropriate hydrodynamic equations for waves in the crystal–fluid system, which predicts electrical characteristics in close agreement with those found experimentally

    The 2018 Provincial Election in New Brunswick

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    New Brunswick’s 2018 election produced a minority legislature, the first in a century. The major parties continue to decline in voter support, and two new parties now have a presence in the Assembly. The election brings New Brunswick’s electoral politics increasingly into the modern Canadian mainstream; one new caucus is the Greens. In other respects, the election made the old new again. The populist People’s Alliance gained three seats partly on the basis of criticism of bilingualism policy. The Alliance and the Progressive Conservatives, in an informal alliance to govern, are all but confined to the anglophone parts of the province, while the defeated Liberals have all their strength in the Acadian north-east. The campaign mattered, as did constitutional conventions.  The Liberals squandered a large lead in the polls, and the parties struggled to sort out the conventions of government formation

    Recall bias during adolescence: Gender differences and associations with depressive symptoms

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    Background: There is a sharp increase in depression in females in mid-adolescence, but we do not understand why. Cognitive theories suggest that people with depression have negative biases in recalling self-referential information. We tested whether recall biases were more negative in girls in early and mid-adolescence and were associated with depressive symptoms. Methods: 315 young and 263 mid-adolescents (11-12 and 13-15 years) completed a surprise test, assessing recall of social evaluation about the self (self-referential) or another person (other-referential). The short Mood and Feelings Questionnaire measured depressive symptoms. We tested the effects of condition (self-referential/otherreferential), valence (positive/negative), gender, and age group on correct recall (hits) and associations with depressive symptoms. Results: There was no evidence for gender or age differences in positive or negative self-referential recall. Selfreferential positive hits were negatively associated with depressive symptoms (adjusted coefficient=-0.38, 95% CI=-0.69–0.08, p=0.01). Self-referential negative hits were positively associated with depressive symptoms (adjusted coefficient=0.45, 95% CI=0.15-0.75, p=0.003), and this association was stronger in females (adjusted interaction p=0.04). Limitations: The reliability and validity of the recall task are unknown. We cannot provide evidence of a causal effect of recall on depressive symptoms in this cross-sectional study. Conclusions: Adolescents who recalled more self-referential negative and fewer self-referential positive words had more severe depressive symptoms. Females did not demonstrate more recall biases, but the association between self-referential negative hits and depressive symptoms was stronger in females. Negative self-referential recall may be a risk factor for depressive symptoms and is a good candidate for longitudinal studies

    A spectroscopic survey for strong galaxy-galaxy lenses

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    We present a spectroscopic survey for strong galaxy-galaxy lenses. Exploiting optimal sight-lines to massive, bulge-dominated galaxies at redshifts z∼0.4z \sim 0.4 with wide-field, multifibre spectroscopy, we anticipate the detection of 10-20 lensed Lyman-α\alpha emitting galaxies at redshifts z \simgreat 3 from a sample of 2000 deflectors. Initial spectroscopic observations are described and the prospects for constraining the emission-line luminosity function of the Lyman-α\alpha emitting population are outlined

    Low-dissipation data bus via coherent quantum dynamics

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    The transfer of information between two physical locations is an essential component of both classical and quantum computing. In quantum computing the transfer of information must be coherent to preserve quantum states and hence the quantum information. We establish a simple protocol for transferring one- and two-electron encoded logical qubits in quantum dot arrays. The theoretical energetic cost of this protocol is calculated - in particular, the cost of freezing and unfreezing tunneling between quantum dots. Our results are compared with the energetic cost of shuttling qubits in quantum dot arrays and transferring classical information using classical information buses. Only our protocol can manage constant dissipation for any chain length. This protocol could reduce the cooling requirements and constraints on scalable architectures for quantum dot quantum computers

    Reward-Processing Behavior in Depressed Participants Relative to Healthy Volunteers: A Systematic Review and Meta-analysis

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    IMPORTANCE: Dysfunctional reward processing is a leading candidate mechanism for the development of certain depressive symptoms, such as anhedonia. However, to our knowledge, there has not yet been a systematic assessment of whether and to what extent depression is associated with impairments on behavioral reward-processing tasks. OBJECTIVE: To determine whether depression is associated with impairments in reward-processing behavior. DATA SOURCES: The MEDLINE/PubMed, Embase, and PsycInfo databases were searched for studies that investigated reward processing using performance on behavioral tasks by individuals with depression and nondepressed control groups, published between January 1, 1946, and August 16, 2019. STUDY SELECTION: Studies that contained data regarding performance by depressed and healthy control groups on reward-processing tasks were included in the systematic review and meta-analysis. DATA EXTRACTION AND SYNTHESIS: Summary statistics comparing performance between depressed and healthy groups on reward-processing tasks were converted to standardized mean difference (SMD) scores, from which summary effect sizes for overall impairment in reward processing and 4 subcomponent categories were calculated. Study quality, heterogeneity, replicability-index, and publication bias were also assessed. MAIN OUTCOME AND MEASURES: Performance on reward-processing tasks. RESULTS: The final data set comprised 48 case-control studies (1387 healthy control individuals and 1767 individuals with major depressive disorder). The mean age was 37.85 years and 58% of the participants were women. These studies used tasks assessing option valuation (n = 9), reward bias (n = 6), reward response vigor (n = 12), reinforcement learning (n = 20), and grip force (n = 1). Across all tasks, depression was associated with small to medium impairments in reward-processing behavior (SMD = 0.345; 95% CI, 0.209-0.480). When examining reward-processing subcomponent categories, impairment was associated with tasks assessing option valuation (SMD = 0.309; 95% CI, 0.147-0.471), reward bias (SMD = 0.644; 95% CI, 0.270-1.017), and reinforcement learning (SMD = 0.352; 95% CI, 0.115-0.588) but not reward response vigor (SMD = 0.083; 95% CI, −0.144 to 0.309). The medication status of the major depressive disorder sample did not explain any of the variance in the overall effect size. There was significant between-study heterogeneity overall and in all subcomponent categories other than option valuation. Significant publication bias was identified overall and in the reinforcement learning category. CONCLUSIONS AND RELEVANCE: Relative to healthy control individuals, individuals with depression exhibit reward-processing impairments, particularly for tests of reward bias, option valuation, and reinforcement learning. Understanding the neural mechanisms driving these associations may assist in designing novel interventions

    Liver transplantation in hemophilia A

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    Four patients with hemophilia A have undergone liver transplantation in our institution, three successfully. The first was a 21-year-old man with chronic active hepatitis (CAH) in whom the effects of previous abdominal operations prevented the satisfactory technical insertion of the new liver. He died intraoperatively. The second patient was a 15-year-old boy with CAH who began to synthesize factor VIII coagulant activity (F VIII:C) within 18 hours of successful liver transplantation and has continued to do so for almost 2 years (F VIII:C range 0.89 to 3.20 U/mL). The first 2 months of his postoperative course were complicated by infections, but since that time he has done well and has returned to school. The third patient was a 48-year-old man with portal fibrosis and severe ascites. He synthesized F VIII:C (range 0.96 to 1.50 U/mL) within six hours after reestablishment of circulation through the new liver. His postoperative course was complicated by numerous infections, and he died with sepsis and an acquired immunodeficiency-like syndrome 4 months after transplantation. The fourth patient was a 47-year-old mild hemophiliac with CAH who produced adequate factor VIII:C levels following transplantation (range 0.79 to 2.80 U/mL). These patients demonstrate that liver transplantation in hemophiliacs with end-stage liver disease may be lifesaving and results in correction of the F VIII:C deficiency and associated hemorrhagic tendency
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