483 research outputs found
Archiving Interactive Narratives at the British Library
This paper describes the creation of the Interactive Narratives collection in the UK Web Archive, as part of the UK Legal Deposit Libraries Emerging Formats Project. The aim of the project is to identify, collect and preserve complex digital publications that are in scope for collection under UK Non-Print Legal Deposit Regulations. This article traces the process of building the Interactive Narratives collection, analysing the different tools and methods used and placing the collection within the wider context of Emerging Formats work and engagement activities at the British Library
Wrist Photoplethysmography Signal Quality Assessment for Reliable Heart Rate Estimate and Morphological Analysis
Photoplethysmographic (PPG) signals are mainly employed for heart rate estimation but are also fascinating candidates in the search for cardiovascular biomarkers. However, their high susceptibility to motion artifacts can lower their morphological quality and, hence, affect the reliability of the extracted information. Low reliability is particularly relevant when signals are recorded in a real-world context, during daily life activities. We aim to develop two classifiers to identify PPG pulses suitable for heart rate estimation (Basic-quality classifier) and morphological analysis (High-quality classifier). We collected wrist PPG data from 31 participants over a 24 h period. We defined four activity ranges based on accelerometer data and randomly selected an equal number of PPG pulses from each range to train and test the classifiers. Independent raters labeled the pulses into three quality levels. Nineteen features, including nine novel features, were extracted from PPG pulses and accelerometer signals. We conducted ten-fold cross-validation on the training set (70%) to optimize hyperparameters of five machine learning algorithms and a neural network, and the remaining 30% was used to test the algorithms. Performances were evaluated using the full features and a reduced set, obtained downstream of feature selection methods. Best performances for both Basic- and High-quality classifiers were achieved using a Support Vector Machine (Acc: 0.96 and 0.97, respectively). Both classifiers outperformed comparable state-of-the-art classifiers. Implementing automatic signal quality assessment methods is essential to improve the reliability of PPG parameters and broaden their applicability in a real-world context
Magnetar central engines in gamma-ray busts follow the universal relation of accreting magnetic stars
Gamma-ray bursts (GRBs), both long and short, are explosive events whose
inner engine is generally expected to be a black hole or a highly magnetic
neutron star (magnetar) accreting high density matter. Recognizing the nature
of GRB central engines, and in particular the formation of neutron stars (NSs),
is of high astrophysical significance. A possible signature of NSs in GRBs is
the presence of a plateau in the early X-ray afterglow. Here we carefully
select a subset of long and short GRBs with a clear plateau, and look for an
additional NS signature in their prompt emission, namely a transition between
accretion and propeller in analogy with accreting, magnetic compact objects in
other astrophysical sources. We estimate from the prompt emission the minimum
accretion luminosity below which the propeller mechanism sets in, and the NS
magnetic field and spin period from the plateau. We demonstrate that these
three quantities obey the same universal relation in GRBs as in other accreting
compact objects switching from accretion to propeller. This relation provides
also an estimate of the radiative efficiency of GRBs, which we find to be
several times lower than radiatively efficient accretion in X-ray binaries and
in agreement with theoretical expectations. These results provide additional
support to the idea that at least some GRBs are powered by magnetars surrounded
by an accretion disc.Comment: 15 pages, 5 figures, accepted for publication in The Astrophysical
Journal Letter
Association of blood pressure with anxiety and depression in a sample of primary care patients
Introduction
According to international scientific literature, and as summarized in the guidelines of the International Society of Hypertension, lowering of blood pressure can prevent cardiovascular accidents. Some studies suggest that hypertension, anxiety, and depression might be inversely correlated.
Objective
To investigate whether blood pressure is associated with anxiety and depression.
Methods
Cross-sectional design. Male and female primary care patients were enrolled, aged 40–80. Criteria of exclusion adopted: use of antidepressants or antipsychotics; previous major cardiovascular event; psychosis or major depression; Type 1-DM; pregnancy and hereditary disease associated to obesity. Anxiety and depression symptoms were assessed using HADS. Waist circumference, hip circumference, blood pressure, HDL, triglycerides, blood sugar, hypertension, albumin concentrations and serum iron were also assessed.
Results
Of the 210 subjects, 84 were men (40%), mean age was 60.88 (SD ± 10.88). Hypertension was found to correlate significantly to anxiety (OR = 0.38; 95% CI = 0.17–0.84), older age (OR = 3.96; 95% CI = 1.88–8.32), cigarette smoking (OR = 0.35; 95%CI = 0.13–0.94), high Body Mass Index (OR = 2.50; 95% CI = 1.24–5.01), Waist-hip ratio (OR = 0.09; 95% CI = 0.02–0.46) and the Index of comorbidity (OR = 16.93; 95% CI = 3.71–77.29).
Conclusions
An inverse association was found between anxiety and hypertension, suggesting the need to clinically manage these two dimensions in a coordinated way. Other findings are well known and already included in prevention campaigns. Further research is needed, also to better understand and explain the causative pathways of this correlation
Convergence study of a DDFV scheme for the Navier-Stokes equations arising in the domain decomposition setting
International audienceWe consider DDFV discretization of the Navier-Stokes equations where the convection fluxes are computed by means of B-schemes, generalizing the classical centered and upwind discretizations. This study is motivated by the analysis of domain decomposition approaches. We investigate on numerical grounds the convergence of the method
DDFV method for Navier-Stokes problem with outflow boundary conditions
International audienceWe propose a Discrete Duality Finite Volume scheme (DDFV for short) for the unsteady incom-pressible Navier-Stokes problem with outflow boundary conditions. As in the continuous case, those conditions are derived from a weak formulation of the equations and they provide an energy estimate of the solution. We prove wellposedness of the scheme and a discrete energy estimate. Finally we perform some numerical tests simulating the flow behind a cylinder inside a long channel to show the robustness of such conditions in the DDFV framework
Numerical analysis of the DDFV method for the Stokes problem with mixed Neumann/Dirichlet boundary conditions
International audienceThe aim of this work is to analyze " Discrete Duality Finite Volume " schemes (DDFV for short) on general meshes by adapting the theory known for the linear Stokes problem with Dirichlet boundary conditions to the case of Neu-mann boundary conditions on a fraction of the boundary. We prove well-posedness for stabilized schemes and we derive some error estimates. Finally, we illustrate some numerical results in which we compare stabilized and unstabilized schemes
Synchronous Lung Cancers: When Same Histological Types Feature Different Molecular Profiles and Response Phenotypes
We discuss the case of synchronous bilateral lung cancers which feature the same histological phenotype and a different EGFR mutational profile. Both histological and molecular characterizations were performed on specimens derived thorough CT-guided fine needle aspiration. A first-line chemotherapy was unsuccessful. Subsequent objective response to the EGFR inhibitor Erlotinib was clearly coherent with the sequencing data and the mutated nodule was effectively reduced (> 50%) after therapy, while the lesion assessed as EGFR wild type featured a slight response. This report has two relevant implications. It points out that in case of multiple malignant lesions at time of diagnosis, molecular profiling should be as extensive as possible and it might contribute to clarify the association between the lesions found. Besides the molecular analysis on cytology specimens could identify an accurate and safe diagnostic approach for clinical use
A case report of hyponatremia after surgery for Conn's adenoma
Primary aldosteronism (PA), also known as Conn's syndrome, is a frequent cause of secondary hypertension. If PA is due to a documented unilateral adrenal adenoma, adrenalectomy is the treatment of choice. Endocrine Society guidelines suggest monitoring potassium after adrenalectomy, while there is no mention of sodium disorders after surgery. Here we report the case of a patient with Conn's syndrome who developed hyponatremia after surgery. This was an unexpected event in the course of the treatment, which sheds light on the fact that low levels of aldosterone strongly influence sodium concentration, and advises clinicians to monitor sodium after adrenalectomy
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