116 research outputs found

    Persistent control of a superconducting qubit by stroboscopic measurement feedback

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    Making a system state follow a prescribed trajectory despite fluctuations and errors commonly consists in monitoring an observable (temperature, blood-glucose level...) and reacting on its controllers (heater power, insulin amount ...). In the quantum domain, there is a change of paradigm in feedback since measurements modify the state of the system, most dramatically when the trajectory goes through superpositions of measurement eigenstates. Here, we demonstrate the stabilization of an arbitrary trajectory of a superconducting qubit by measurement based feedback. The protocol benefits from the long coherence time (T2>10ÎĽT_2>10 \mus) of the 3D transmon qubit, the high efficiency (82%) of the phase preserving Josephson amplifier, and fast electronics ensuring less than 500 ns delay. At discrete time intervals, the state of the qubit is measured and corrected in case an error is detected. For Rabi oscillations, where the discrete measurements occur when the qubit is supposed to be in the measurement pointer states, we demonstrate an average fidelity of 85% to the targeted trajectory. For Ramsey oscillations, which does not go through pointer states, the average fidelity reaches 75%. Incidentally, we demonstrate a fast reset protocol allowing to cool a 3D transmon qubit down to 0.6% in the excited state.Comment: 7 pages, 3 figures and 1 table. Supplementary information available as an ancilla fil

    Low statistical power in biomedical science:a review of three human research domains

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    Studies with low statistical power increase the likelihood that a statistically significant finding represents a false positive result. We conducted a review of meta-analyses of studies investigating the association of biological, environmental or cognitive parameters with neurological, psychiatric and somatic diseases, excluding treatment studies, in order to estimate the average statistical power across these domains. Taking the effect size indicated by a meta-analysis as the best estimate of the likely true effect size, and assuming a threshold for declaring statistical significance of 5%, we found that approximately 50% of studies have statistical power in the 0–10% or 11–20% range, well below the minimum of 80% that is often considered conventional. Studies with low statistical power appear to be common in the biomedical sciences, at least in the specific subject areas captured by our search strategy. However, we also observe evidence that this depends in part on research methodology, with candidate gene studies showing very low average power and studies using cognitive/behavioural measures showing high average power. This warrants further investigation

    Progression of diabetic nephropathy in normotensive type 1 diabetic patients

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    Progression of diabetic nephropathy in normotensive type 1 diabetic patientsBackgroundThe first aim of our long-term study was to describe the natural history of diabetic nephropathy in 59 normotensive type 1 diabetic patients. Secondly, we evaluated genetic and nongenetic progression promoters.MethodsThe following progression promoters were determined: the insertion/deletion polymorphism in the angiotensin converting enzyme (ACE) gene, blood pressure, albuminuria, hemoglobin A1c, cholesterol, smoking, height, and gender. We studied the natural history by measuring 51Cr-EDTA plasma clearance at yearly intervals at least three times during [median (range)] 5.5 (2.2 to 18.3) years.ResultsAt baseline the three groups (II, N = 11; ID, N = 25, and DD, N = 23) had comparable GFR (103 ± 16; 99 ± 19; 113 ± 22 ml/min/1.73 m2, respectively; mean ± SD), arterial blood pressure, albuminuria, and hemoglobin A1c. During the follow-up there was a median rate of decline in GFR in all 59 patients of 1.2 (range 12.9 to –4.4) ml/min/year. During the study period no significant differences were observed in: the rate of decline in glomerular filtration rate [median (range) 0.9 (10.6 to –1.9); 2.5 (12.9 to –4.4); 1.4 (10.8 to –1.9 ml/min/year)], arterial blood pressure, albuminuria, hemoglobin A1c or cholesterol between the three groups (II, ID and DD), respectively. At baseline, multiple linear regression analysis including the above-mentioned putative risk factors revealed that albuminuria, short stature, and male gender independently predict an enhanced decline in GFR [R2 (adjusted) = 0.33; P < 0.002]. During the follow-up period, only albuminuria acted as an independent progression promoter [R2 (adjusted) = 0.37; P < 0.0001].ConclusionsOur study revealed a rather slow progression of kidney disease in normotensive type 1 diabetic patients with diabetic nephropathy. Albuminuria, short stature, and male gender act as progression promoters in such patients

    Obsessive compulsive disorder- prevalence in Xhosaspeaking schizophrenia patients

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    Obsessive compulsive disorder (OCD) has been reported in up to 31% of  schizophrenia sufferers. This study evaluated the presence of OCD in a  Xhosa-speaking schizophrenia group. Xhosa patients (N = 509, including 100  sibships) with schizophrenia were recruited from hospital and community settings. The patients underwent a structured clinical interview for the presence  of lifetime co-morbid schizo-phrenia and OCD. Only 3 patients (0.5%) fulfilled criteria for OCD. No concordance for OCD was noted in the  sibship group. Our findings differ from those in other parts of the world, and if replicated, might suggest unique protective environmental or genetic factors  for OCD in certain ethnic groups

    BEEHOPE: um projeto de conservação das subespécies nativas de abelha da Europa Ocidental (linhagem M) à escala Europeia

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    O projeto BEEHOPE, com o título original “Honeybee conservation centres in western Europe - an innovative strategy using sustainable beekeeping to reduce honeybee decline”, foi um dos 10 aprovados na área da biodiversidade do 5º concurso transnacional (2013-2014) BiodivErsA/FACCE-JPI (http://www.biodiversa.org/766), subordinado ao tema “Promover sinergias e reduzir o compromisso entre o abastecimento de alimentos, biodiversidade e serviços dos ecossistemas”. A diversidade nativa das populações de abelha melífera (Apis mellifera) da linhagem da Europa ocidental (M) tem vindo a ser crescentemente ameaçada pela introdução massiva de colónias da linhagem da Europa oriental (C, onde se incluem as subespécies A. m. ligustica, A. m. carnica, A. m. macedónica etc.), e também por outros fatores bióticos (Varroa e vírus associados, Nosema etc.) e abióticos (pesticidas, perda e fragmentação de habitat, alterações climáticas etc.). É neste contexto que surge o projeto BEEHOPE, o qual tem por objetivo último contribuir para a conservação da diversidade genética das populações de abelha melífera da linhagem M.info:eu-repo/semantics/publishedVersio

    Relationship between molecular pathogen detection and clinical disease in febrile children across Europe: a multicentre, prospective observational study

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    Background: The PERFORM study aimed to understand causes of febrile childhood illness by comparing molecular pathogen detection with current clinical practice. Methods: Febrile children and controls were recruited on presentation to hospital in 9 European countries 2016-2020. Each child was assigned a standardized diagnostic category based on retrospective review of local clinical and microbiological data. Subsequently, centralised molecular tests (CMTs) for 19 respiratory and 27 blood pathogens were performed. Findings: Of 4611 febrile children, 643 (14%) were classified as definite bacterial infection (DB), 491 (11%) as definite viral infection (DV), and 3477 (75%) had uncertain aetiology. 1061 controls without infection were recruited. CMTs detected blood bacteria more frequently in DB than DV cases for N. meningitidis (OR: 3.37, 95% CI: 1.92-5.99), S. pneumoniae (OR: 3.89, 95% CI: 2.07-7.59), Group A streptococcus (OR 2.73, 95% CI 1.13-6.09) and E. coli (OR 2.7, 95% CI 1.02-6.71). Respiratory viruses were more common in febrile children than controls, but only influenza A (OR 0.24, 95% CI 0.11-0.46), influenza B (OR 0.12, 95% CI 0.02-0.37) and RSV (OR 0.16, 95% CI: 0.06-0.36) were less common in DB than DV cases. Of 16 blood viruses, enterovirus (OR 0.43, 95% CI 0.23-0.72) and EBV (OR 0.71, 95% CI 0.56-0.90) were detected less often in DB than DV cases. Combined local diagnostics and CMTs respectively detected blood viruses and respiratory viruses in 360 (56%) and 161 (25%) of DB cases, and virus detection ruled-out bacterial infection poorly, with predictive values of 0.64 and 0.68 respectively. Interpretation: Most febrile children cannot be conclusively defined as having bacterial or viral infection when molecular tests supplement conventional approaches. Viruses are detected in most patients with bacterial infections, and the clinical value of individual pathogen detection in determining treatment is low. New approaches are needed to help determine which febrile children require antibiotics

    Relationship between molecular pathogen detection and clinical disease in febrile children across Europe:a multicentre, prospective observational study

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    Background: The PERFORM study aimed to understand causes of febrile childhood illness by comparing molecular pathogen detection with current clinical practice. Methods: Febrile children and controls were recruited on presentation to hospital in 9 European countries 2016–2020. Each child was assigned a standardized diagnostic category based on retrospective review of local clinical and microbiological data. Subsequently, centralised molecular tests (CMTs) for 19 respiratory and 27 blood pathogens were performed. Findings: Of 4611 febrile children, 643 (14%) were classified as definite bacterial infection (DB), 491 (11%) as definite viral infection (DV), and 3477 (75%) had uncertain aetiology. 1061 controls without infection were recruited. CMTs detected blood bacteria more frequently in DB than DV cases for N. meningitidis (OR: 3.37, 95% CI: 1.92–5.99), S. pneumoniae (OR: 3.89, 95% CI: 2.07–7.59), Group A streptococcus (OR 2.73, 95% CI 1.13–6.09) and E. coli (OR 2.7, 95% CI 1.02–6.71). Respiratory viruses were more common in febrile children than controls, but only influenza A (OR 0.24, 95% CI 0.11–0.46), influenza B (OR 0.12, 95% CI 0.02–0.37) and RSV (OR 0.16, 95% CI: 0.06–0.36) were less common in DB than DV cases. Of 16 blood viruses, enterovirus (OR 0.43, 95% CI 0.23–0.72) and EBV (OR 0.71, 95% CI 0.56–0.90) were detected less often in DB than DV cases. Combined local diagnostics and CMTs respectively detected blood viruses and respiratory viruses in 360 (56%) and 161 (25%) of DB cases, and virus detection ruled-out bacterial infection poorly, with predictive values of 0.64 and 0.68 respectively. Interpretation: Most febrile children cannot be conclusively defined as having bacterial or viral infection when molecular tests supplement conventional approaches. Viruses are detected in most patients with bacterial infections, and the clinical value of individual pathogen detection in determining treatment is low. New approaches are needed to help determine which febrile children require antibiotics. Funding: EU Horizon 2020 grant 668303.</p
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