216 research outputs found

    Exciting the Higgs mode in a strongly-interacting Fermi gas by interaction modulation

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    We study the Higgs mode of a strongly-interacting Fermi gas in the crossover regime between a fermionic and bosonic superfluid. By periodically modulating the interaction strength of the gas, we parametrically excite the Higgs mode and study its resonance frequency and line width as a function of both interaction strength and temperature. We find that the resonance frequency at low temperature agrees with a local-density approximation of the pairing gap. Both frequency and line width do not exhibit a pronounced variation with temperature, which is theoretically unexpected, however, in qualitative agreement with a different recent study

    A new 3D monitor-based randomdot stereotest for children

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    PURPOSE. Objective testing for random-dot stereovision in preverbal children requires some type of dissociating glasses. Drawbacks of such methods are the alteration of natural visual conditions and sometimes nonacceptance of the glasses. For this reason, a new, natural method for random-dot stereopsis measurement was developed and tested. METHODS. Random-dot circles (diameter 10 cm, crossed disparity of 0.34°) were generated on an autostereoscopic display and presented to 18 normal children (mean age, 5.1 Ϯ 1.1 years), 8 with anisometropic amblyopia (mean age, 4.9 Ϯ 1.3 years), 14 with infantile essential esotropia (mean age, 5.3 Ϯ 0.7 years), and 16 with primary microstrabismus (mean age, 5.2 Ϯ 1.4 years). While the position of the stimulus randomly changed among four possible locations, eye positions were recorded by infrared photo-oculography. If two or more consecutive saccades ends corresponded to the stimulus coordinates, a positive response was assumed. The results with the new test were compared with the ability to recognize the Lang I random-dot stereotest. RESULTS. Twenty-four of 26 Lang I-positive children had positive responses (sensitivity of 92.3%), 29 of 30 Lang I-negative children had negative three-dimensional (3D) stimulus responses (specificity, 96.7%). The positive predictive value of the new test was 0.96 (95% CI, 0.79 -0.99); the negative predictive value, 0.94 (95% CI, 0.78 -0.99); and the overall accuracy, 0.95 (95% CI, 0.85-0.99). CONCLUSIONS. This new 3D monitor-based test allows objective assessment of random-dot stereopsis in children older than 3 years. (Invest Ophthalmol Vis Sci. 2006;47:4842-4846

    CARACTERIZAÇÃO FÍSICO-QUÍMICA DE MEL DE DIFERENTES FLORADAS PRODUZIDO POR APICULTORES ORGÂNICOS DA REGIÃO CENTRO-SUL E SUDESTE NO ESTADO DO PARANÁ

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    O tipo da florada, condições climáticas, estádio de maturação, espécie de abelha, processamento e armazenamento pode interferir na composição físico-química do mel, que está diretamente ligada ao controle da qualidade do mel produzido. O trabalho possibilitou caracterizar físico-quimicamente, com análises de cor, condutividade e umidade o mel de Apis melífera produzido por apicultores do programa orgânico das regiões Centro-sul e Sudeste no estado do Paraná. O mel foi obtido diretamente de 31 apicultores, as amostras foram retiradas de recipientes de inox de com 270 a 300 kg de mel envazado, durante três safras que englobaram os seguintes períodos 01.07.2010 à 30.06.2011, 01.07.2011 à 30.06.2012 e 01.07.2012 à 30.06.2013. Nas amostras houve predominância das cores âmbar claro e âmbar escuro, 81 e 11%, respectivamente, e a cor branca mostrou-se de maneira pouco representativa com apenas 6 amostragem na safra de 2011/2012. A umidade apresentou valor abaixo de 19% para maioria das amostras analisadas. No entanto, ao se comparar os valores de umidade com a legislação vigente, observou-se que somente (0,4%) das amostras ultrapassaram os limites preconizados. Em relação à condutividade elétrica das safras estudadas, as amostras (73%) apresentou se abaixo de 800 μS. Comparando as três safras, a de 2011/2012 foi a que se destacou na quantidade produzida, devido as condições climáticas que proporcionaram boas floradas. No entanto, a safra de 2010/2011 foi a menos favorecida. Desta forma, nota-se que o manejo adequado das colmeias possibilita a conservação da integridade do mel e a geração de um produto de boa qualidade

    Patient recruitment into clinical studies of solid malignancies during the COVID-19 pandemic in a tertiary cancer center

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    Background and purpose: To analyze clinical trial activities and patient recruitment numbers into prospective clinical studies for solid malignancies during the COVID-19 pandemic in a tertiary cancer center. Materials and methods: Patient recruitment numbers in prospective clinical studies of solid malignancies were retrospectively analyzed for the years 2019 – 2021 at the Comprehensive Cancer Center Zurich (CCCZ). Changes in recruitment numbers were tested for association with organ-specific subunits, as well as organizational and treatment-related trial characteristics. To assess differences between categorical variables, Chi-squared test was used. For uni- and multivariate analysis, Cox proportional hazards were calculated. Results: In 2019, there were a total of 107 studies (registry trials, clinical phase I-III trials, and translational studies) recruiting 304 patients at the CCCZ. During the COVID-19 pandemic in 2020 and 2021, there were 120 and 125 active trials with a total recruitment of 355 and 666 patients, respectively. No significant differences between the subunits and study characteristics in changes of patient recruitment in clinical phase I-III trials were identified when the year prior to the COVID-19 pandemic (2019) was compared to the first year of the pandemic (2020) and to 2020-2021. Conclusions: Despite healthcare systems around the world have experienced significant disruption due to the COVID-19 pandemic, data from our tertiary cancer center showed that clinical trial activities were maintained at a high level during the pandemic

    Increasing test specificity without impairing sensitivity: lessons learned from SARS-CoV-2 serology

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    Background: Serological tests are widely used in various medical disciplines for diagnostic and monitoring purposes. Unfortunately, the sensitivity and specificity of test systems are often poor, leaving room for false-positive and false-negative results. However, conventional methods were used to increase specificity and decrease sensitivity and vice versa. Using SARS-CoV-2 serology as an example, we propose here a novel testing strategy: the € sensitivity improved two-test' or € SIT²' algorithm. Methods: SIT² involves confirmatory retesting of samples with results falling in a predefined retesting zone of an initial screening test, with adjusted cut-offs to increase sensitivity. We verified and compared the performance of SIT² to single tests and orthogonal testing (OTA) in an Austrian cohort (1117 negative, 64 post-COVID-positive samples) and validated the algorithm in an independent British cohort (976 negatives and 536 positives). Results: The specificity of SIT² was superior to single tests and non-inferior to OTA. The sensitivity was maintained or even improved using SIT² when compared with single tests or OTA. SIT² allowed correct identification of infected individuals even when a live virus neutralisation assay could not detect antibodies. Compared with single testing or OTA, SIT² significantly reduced total test errors to 0.46% (0.24-0.65) or 1.60% (0.94-2.38) at both 5% or 20% seroprevalence. Conclusion: For SARS-CoV-2 serology, SIT² proved to be the best diagnostic choice at both 5% and 20% seroprevalence in all tested scenarios. It is an easy to apply algorithm and can potentially be helpful for the serology of other infectious diseases
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