2,487 research outputs found

    Evidential Uncertainty Quantification: A Variance-Based Perspective

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    Uncertainty quantification of deep neural networks has become an active field of research and plays a crucial role in various downstream tasks such as active learning. Recent advances in evidential deep learning shed light on the direct quantification of aleatoric and epistemic uncertainties with a single forward pass of the model. Most traditional approaches adopt an entropy-based method to derive evidential uncertainty in classification, quantifying uncertainty at the sample level. However, the variance-based method that has been widely applied in regression problems is seldom used in the classification setting. In this work, we adapt the variance-based approach from regression to classification, quantifying classification uncertainty at the class level. The variance decomposition technique in regression is extended to class covariance decomposition in classification based on the law of total covariance, and the class correlation is also derived from the covariance. Experiments on cross-domain datasets are conducted to illustrate that the variance-based approach not only results in similar accuracy as the entropy-based one in active domain adaptation but also brings information about class-wise uncertainties as well as between-class correlations. The code is available at https://github.com/KerryDRX/EvidentialADA. This alternative means of evidential uncertainty quantification will give researchers more options when class uncertainties and correlations are important in their applications.Comment: IEEE/CVF Winter Conference on Applications of Computer Vision (WACV) 202

    155-day Periodicity in Solar Cycles 3 and 4

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    The near 155 days solar periodicity, so called Rieger periodicity, was first detected in solar flares data and later confirmed with other important solar indices. Unfortunately, a comprehensive analysis on the occurrence of this periodicity during previous centuries can be further complicated due to the poor quality of the sunspot number time-series. We try to detect the Rieger periodicity during the solar cycles 3 and 4 using information on aurorae observed at mid and low latitudes. We use two recently discovered aurora datasets, observed in the last quarter of the 18th century from UK and Spain. Besides simple histograms of time between consecutive events we analyse monthly series of number of aurorae observed using different spectral analysis (MTM and Wavelets). The histograms show the probable presence of Rieger periodicity during cycles 3 and 4. However different spectral analysis applied has only confirmed undoubtedly this hypothesis for solar cycle 3.Comment: 13 pages, 6 figures, to appear in New Astronom

    Psychosocial interventions for patients with head and neck cancer.

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    BACKGROUND: A diagnosis of head and neck cancer, like many other cancers, can lead to significant psychosocial distress. Patients with head and neck cancer can have very specific needs, due to both the location of their disease and the impact of treatment, which can interfere with basic day-to-day activities such as eating, speaking and breathing. There is a lack of clarity on the effectiveness of the interventions developed to address the psychosocial distress experienced by patients living with head and neck cancer. OBJECTIVES: To assess the effectiveness of psychosocial interventions to improve quality of life and psychosocial well-being for patients with head and neck cancer. SEARCH METHODS: We searched the Cochrane Ear, Nose and Throat Disorders Group Trials Register; the Cochrane Central Register of Controlled Trials (CENTRAL); PubMed; EMBASE; CINAHL; Web of Science; BIOSIS Previews; Cambridge Scientific Abstracts; ICTRP and additional sources for published and unpublished trials. The date of the most recent search was 17 December 2012. SELECTION CRITERIA: We selected randomised controlled trials and quasi-randomised controlled trials of psychosocial interventions for adults with head and neck cancer. For trials to be included the psychosocial intervention had to involve a supportive relationship between a trained helper and individuals diagnosed with head and neck cancer. Outcomes had to be assessed using a validated quality of life or psychological distress measure, or both. DATA COLLECTION AND ANALYSIS: Two review authors independently selected trials, extracted data and assessed the risk of bias, with mediation from a third author where required. Where possible, we extracted outcome measures for combining in meta-analyses. We compared continuous outcomes using either mean differences (MD) or standardised mean differences (SMD) and 95% confidence intervals (CI), with a random-effects model. We conducted meta-analyses for the primary outcome measure of quality of life and secondary outcome measures of psychological distress, including anxiety and depression. We subjected the remaining outcome measures (self esteem, coping, adjustment to cancer, body image) to a narrative synthesis, due to the limited number of studies evaluating these specific outcomes and the wide divergence of assessment tools used. MAIN RESULTS: Seven trials, totaling 542 participants, met the eligibility criteria. Studies varied widely on risk of bias, interventions used and outcome measures reported. From these studies, there was no evidence to suggest that psychosocial intervention promotes global quality of life for patients with head and neck cancer at end of intervention (MD 1.23, 95% CI -5.82 to 8.27) as measured by the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ-C30). This quality of life tool includes five functional scales, namely cognitive, physical, emotional, social and role. There was no evidence to demonstrate that psychosocial intervention provides an immediate or medium-term improvement on any of these five functional scales. From the data available, there was no significant change in levels of anxiety (SMD -0.09, 95% CI -0.40 to 0.23) or depression following intervention (SMD -0.03, 95% CI -0.24 to 0.19). At present, there is insufficient evidence to refute or support the effectiveness of psychosocial intervention for patients with head and neck cancer. AUTHORS' CONCLUSIONS: The evidence for psychosocial intervention is limited by the small number of studies, methodological shortcomings such as lack of power, difficulties with comparability between types of interventions and a wide divergence in outcome measures used. Future research should be targeted at patients who screen positive for distress and use validated outcome measures, such as the EORTC scale, as a measure of quality of life. These studies should implement interventions that are theoretically derived. Other shortcomings should be addressed in future studies, including using power calculations that may encourage multi-centred collaboration to ensure adequate sample sizes are recruited

    Inhaled corticosteroids and the risk of pneumonia in people with asthma

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    Background In clinical trials, the use of inhaled corticosteroids is associated with an increased risk of pneumonia in people with COPD, but whether the same is true for people with asthma is not known. Methods With the use of primary care data from The Health Improvement Network, we identified people with asthma, and from this cohort, we identified patients with pneumonia or lower respiratory tract infection and age- and sex-matched control subjects. Conditional logistic regression was used to determine the association between the dose and type of inhaled corticosteroid and the risk of pneumonia or lower respiratory tract infection. Results A dose-response relationship was found between the strength of inhaled corticosteroid dose and risk of pneumonia or lower respiratory tract infection (P < .001 for trend) such that after adjusting for confounders, people receiving the highest strength of inhaled corticosteroid (≥ 1,000 μg) had a 2.04 (95% CI, 1.59-2.64) increased risk of pneumonia or lower respiratory tract infection compared with those with asthma who did not have a prescription for inhaled corticosteroids within the previous 90 days. Conclusions People with asthma receiving inhaled corticosteroids are at an increased risk of pneumonia or lower respiratory infection, with those receiving higher doses being at greater risk. Pneumonia should be considered as a possible side effect of inhaled corticosteroids, and the lowest possible dose of inhaled corticosteroids should be used in the management of asthma

    A role for two-pore potassium (K2P) channels in endometrial epithelial function.

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    The human endometrial epithelium is pivotal to menstrual cycle progression, implantation and early pregnancy. Endometrial function is directly regulated by local factors that include pH, oxygen tension and ion concentrations to generate an environment conducive to fertilization. A superfamily of potassium channels characterized by two-pore domains (K2P) and encoded by KCNK genes is implicated in the control of the cell resting membrane potential through the generation of leak currents and modulation by various physicochemical stimuli. The aims of the study were to determine the expression and function of K2P channel subtypes in proliferative and secretory phase endometrium obtained from normo-ovulatory women and in an endometrial cancer cell line. Using immunochemical methods, real-time qRT-PCR proliferation assays and electrophysiology. Our results demonstrate mRNA for several K2P channel subtypes in human endometrium with molecular expression of TREK-1 shown to be higher in proliferative than secretory phase endometrium (P < 0.001). The K2P channel blockers methanandamide, lidocaine, zinc and curcumin had antiproliferative effects (P < 0.01) in an endometrial epithelial cancer cell line indicating a role for TASK and TREK-1 channels in proliferation. Tetraethylammonium- and 4-aminopyridine-insensitive outwards currents were inhibited at all voltages by reducing extracellular pH from 7.4 to 6.6. Higher expression of TREK-1 expression in proliferative phase endometrium may, in part, underlie linked to increased cell division. The effects of pH and a lack of effect of non-specific channel blockers of voltage-gated potassium channels imply a role for K2P channels in the regulation of human endometrial function

    Coronal radiation of a cusp of spun-up stars and the X-ray luminosity of Sgr A*

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    Chandra has detected optically thin, thermal X-ray emission with a size of ~1 arcsec and luminosity ~10^33 erg/s from the direction of the Galactic supermassive black hole (SMBH), Sgr A*. We suggest that a significant or even dominant fraction of this signal may be produced by several thousand late-type main-sequence stars that possibly hide in the central ~0.1 pc region of the Galaxy. As a result of tidal spin-ups caused by close encounters with other stars and stellar remnants, these stars should be rapidly rotating and hence have hot coronae, emitting copious amounts of X-ray emission with temperatures kT<~ a few keV. The Chandra data thus place an interesting upper limit on the space density of (currently unobservable) low-mass main-sequence stars near Sgr A*. This bound is close to and consistent with current constraints on the central stellar cusp provided by infrared observations. If coronally active stars do provide a significant fraction of the X-ray luminosity of Sgr A*, it should be variable on hourly and daily time scales due to giant flares occurring on different stars. Another consequence is that the quiescent X-ray luminosity and accretion rate of the SMBH are yet lower than believed before.Comment: 18 pages, 7 figures. Accepted to MNRA

    Paleomagnetism. Solar nebula magnetic fields recorded in the Semarkona meteorite.

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    Magnetic fields are proposed to have played a critical role in some of the most enigmatic processes of planetary formation by mediating the rapid accretion of disk material onto the central star and the formation of the first solids. However, there have been no experimental constraints on the intensity of these fields. Here we show that dusty olivine-bearing chondrules from the Semarkona meteorite were magnetized in a nebular field of 54 ± 21 microteslas. This intensity supports chondrule formation by nebular shocks or planetesimal collisions rather than by electric currents, the x-wind, or other mechanisms near the Sun. This implies that background magnetic fields in the terrestrial planet-forming region were likely 5 to 54 microteslas, which is sufficient to account for measured rates of mass and angular momentum transport in protoplanetary disks.This is the accepted manuscript. The final version is available from Science at http://www.sciencemag.org/content/346/6213/1089.abstract

    Focusing on rare diseases in China: are we there yet?

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