105 research outputs found
SiamAF: Learning Shared Information from ECG and PPG Signals for Robust Atrial Fibrillation Detection
Atrial fibrillation (AF) is the most common type of cardiac arrhythmia. It is
associated with an increased risk of stroke, heart failure, and other
cardiovascular complications, but can be clinically silent. Passive AF
monitoring with wearables may help reduce adverse clinical outcomes related to
AF. Detecting AF in noisy wearable data poses a significant challenge, leading
to the emergence of various deep learning techniques. Previous deep learning
models learn from a single modality, either electrocardiogram (ECG) or
photoplethysmography (PPG) signals. However, deep learning models often
struggle to learn generalizable features and rely on features that are more
susceptible to corruption from noise, leading to sub-optimal performances in
certain scenarios, especially with low-quality signals. Given the increasing
availability of ECG and PPG signal pairs from wearables and bedside monitors,
we propose a new approach, SiamAF, leveraging a novel Siamese network
architecture and joint learning loss function to learn shared information from
both ECG and PPG signals. At inference time, the proposed model is able to
predict AF from either PPG or ECG and outperforms baseline methods on three
external test sets. It learns medically relevant features as a result of our
novel architecture design. The proposed model also achieves comparable
performance to traditional learning regimes while requiring much fewer training
labels, providing a potential approach to reduce future reliance on manual
labeling
Thermodynamic Geometry: Evolution, Correlation and Phase Transition
Under the fluctuation of the electric charge and atomic mass, this paper
considers the theory of the thin film depletion layer formation of an ensemble
of finitely excited, non-empty -orbital heavy materials, from the
thermodynamic geometric perspective. At each state of the local adiabatic
evolutions, we examine the nature of the thermodynamic parameters,
\textit{viz.}, electric charge and mass, changing at each respective
embeddings. The definition of the intrinsic Riemannian geometry and
differential topology offers the properties of (i) local heat capacities, (ii)
global stability criterion and (iv) global correlation length. Under the
Gaussian fluctuations, such an intrinsic geometric consideration is anticipated
to be useful in the statistical coating of the thin film layer of a desired
quality-fine high cost material on a low cost durable coatant. From the
perspective of the daily-life applications, the thermodynamic geometry is thus
intrinsically self-consistent with the theory of the local and global economic
optimizations. Following the above procedure, the quality of the thin layer
depletion could self-consistently be examined to produce an economic, quality
products at a desired economic value.Comment: 22 pages, 5 figures, Keywords: Thermodynamic Geometry, Metal
Depletion, Nano-science, Thin Film Technology, Quality Economic
Characterization; added 1 figure and 1 section (n.10), and edited
bibliograph
Ruelle-Perron-Frobenius spectrum for Anosov maps
We extend a number of results from one dimensional dynamics based on spectral
properties of the Ruelle-Perron-Frobenius transfer operator to Anosov
diffeomorphisms on compact manifolds. This allows to develop a direct operator
approach to study ergodic properties of these maps. In particular, we show that
it is possible to define Banach spaces on which the transfer operator is
quasicompact. (Information on the existence of an SRB measure, its smoothness
properties and statistical properties readily follow from such a result.) In
dimension we show that the transfer operator associated to smooth random
perturbations of the map is close, in a proper sense, to the unperturbed
transfer operator. This allows to obtain easily very strong spectral stability
results, which in turn imply spectral stability results for smooth
deterministic perturbations as well. Finally, we are able to implement an Ulam
type finite rank approximation scheme thus reducing the study of the spectral
properties of the transfer operator to a finite dimensional problem.Comment: 58 pages, LaTe
Immune Dysregulation and Self-Reactivity in Schizophrenia: Do Some Cases of Schizophrenia Have an Autoimmune Basis?
Schizophrenia affects 1% of the world's population, but its cause remains obscure. Numerous theories have been proposed regarding the cause of schizophrenia, ranging from developmental or neurodegenerative processes or neurotransmitter abnormalities to infectious or autoimmune processes. In this review, findings suggestive of immune dysregulation and reactivity to self in patients with schizophrenia are examined with reference to criteria for defining whether or not a human disease is autoimmune in origin. Associations with other autoimmune diseases and particular MHC haplotypes, increased serum levels of autoantibodies, and in vivo and in vitro replication of some of the functional and ultrastructural abnormalities of schizophrenia by transfer of autoantibodies from the sera of patients with schizophrenia suggest that, in some patients at least, autoimmune mechanisms could play a role in the development of disease. Recent findings regarding specific autoimmune responses directed against neurotransmitter receptors in the brain in patients with schizophrenia will also be reviewed
The Cosparse Analysis Model and Algorithms
After a decade of extensive study of the sparse representation synthesis
model, we can safely say that this is a mature and stable field, with clear
theoretical foundations, and appealing applications. Alongside this approach,
there is an analysis counterpart model, which, despite its similarity to the
synthesis alternative, is markedly different. Surprisingly, the analysis model
did not get a similar attention, and its understanding today is shallow and
partial. In this paper we take a closer look at the analysis approach, better
define it as a generative model for signals, and contrast it with the synthesis
one. This work proposes effective pursuit methods that aim to solve inverse
problems regularized with the analysis-model prior, accompanied by a
preliminary theoretical study of their performance. We demonstrate the
effectiveness of the analysis model in several experiments.Comment: Submitted (2011
Height and timing of growth spurt during puberty in young people living with vertically acquired HIV in Europe and Thailand.
OBJECTIVE: The aim of this study was to describe growth during puberty in young people with vertically acquired HIV. DESIGN: Pooled data from 12 paediatric HIV cohorts in Europe and Thailand. METHODS: One thousand and ninety-four children initiating a nonnucleoside reverse transcriptase inhibitor or boosted protease inhibitor based regimen aged 1-10 years were included. Super Imposition by Translation And Rotation (SITAR) models described growth from age 8 years using three parameters (average height, timing and shape of the growth spurt), dependent on age and height-for-age z-score (HAZ) (WHO references) at antiretroviral therapy (ART) initiation. Multivariate regression explored characteristics associated with these three parameters. RESULTS: At ART initiation, median age and HAZ was 6.4 [interquartile range (IQR): 2.8, 9.0] years and -1.2 (IQR: -2.3 to -0.2), respectively. Median follow-up was 9.1 (IQR: 6.9, 11.4) years. In girls, older age and lower HAZ at ART initiation were independently associated with a growth spurt which occurred 0.41 (95% confidence interval 0.20-0.62) years later in children starting ART age 6 to 10 years compared with 1 to 2 years and 1.50 (1.21-1.78) years later in those starting with HAZ less than -3 compared with HAZ at least -1. Later growth spurts in girls resulted in continued height growth into later adolescence. In boys starting ART with HAZ less than -1, growth spurts were later in children starting ART in the oldest age group, but for HAZ at least -1, there was no association with age. Girls and boys who initiated ART with HAZ at least -1 maintained a similar height to the WHO reference mean. CONCLUSION: Stunting at ART initiation was associated with later growth spurts in girls. Children with HAZ at least -1 at ART initiation grew in height at the level expected in HIV negative children of a comparable age
Daily omega-3 fatty acid intake and depression in Japanese patients with newly diagnosed lung cancer
patients with newly diagnosed lung cance
Nutritional therapies for mental disorders
According to the Diagnostic and Statistical Manual of Mental Disorders, 4 out of the 10 leading causes of disability in the US and other developed countries are mental disorders. Major depression, bipolar disorder, schizophrenia, and obsessive compulsive disorder (OCD) are among the most common mental disorders that currently plague numerous countries and have varying incidence rates from 26 percent in America to 4 percent in China. Though some of this difference may be attributable to the manner in which individual healthcare providers diagnose mental disorders, this noticeable distribution can be also explained by studies which show that a lack of certain dietary nutrients contribute to the development of mental disorders. Notably, essential vitamins, minerals, and omega-3 fatty acids are often deficient in the general population in America and other developed countries; and are exceptionally deficient in patients suffering from mental disorders. Studies have shown that daily supplements of vital nutrients often effectively reduce patients' symptoms. Supplements that contain amino acids also reduce symptoms, because they are converted to neurotransmitters that alleviate depression and other mental disorders. Based on emerging scientific evidence, this form of nutritional supplement treatment may be appropriate for controlling major depression, bipolar disorder, schizophrenia and anxiety disorders, eating disorders, attention deficit disorder/attention deficit hyperactivity disorder (ADD/ADHD), addiction, and autism. The aim of this manuscript is to emphasize which dietary supplements can aid the treatment of the four most common mental disorders currently affecting America and other developed countries: major depression, bipolar disorder, schizophrenia, and obsessive compulsive disorder (OCD)
A Panorama on Multiscale Geometric Representations, Intertwining Spatial, Directional and Frequency Selectivity
The richness of natural images makes the quest for optimal representations in
image processing and computer vision challenging. The latter observation has
not prevented the design of image representations, which trade off between
efficiency and complexity, while achieving accurate rendering of smooth regions
as well as reproducing faithful contours and textures. The most recent ones,
proposed in the past decade, share an hybrid heritage highlighting the
multiscale and oriented nature of edges and patterns in images. This paper
presents a panorama of the aforementioned literature on decompositions in
multiscale, multi-orientation bases or dictionaries. They typically exhibit
redundancy to improve sparsity in the transformed domain and sometimes its
invariance with respect to simple geometric deformations (translation,
rotation). Oriented multiscale dictionaries extend traditional wavelet
processing and may offer rotation invariance. Highly redundant dictionaries
require specific algorithms to simplify the search for an efficient (sparse)
representation. We also discuss the extension of multiscale geometric
decompositions to non-Euclidean domains such as the sphere or arbitrary meshed
surfaces. The etymology of panorama suggests an overview, based on a choice of
partially overlapping "pictures". We hope that this paper will contribute to
the appreciation and apprehension of a stream of current research directions in
image understanding.Comment: 65 pages, 33 figures, 303 reference
Synthetic Plasmodium-Like Hemozoin Activates the Immune Response: A Morphology - Function Study
Increasing evidence points to an important role for hemozoin (HZ), the malaria pigment, in the immunopathology related to this infection. However, there is no consensus as to whether HZ exerts its immunostimulatory activity in absence of other parasite or host components. Contamination of native HZ preparations and the lack of a unified protocol to produce crystals that mimic those of Plasmodium HZ (PHZ) are major technical limitants when performing functional studies with HZ. In fact, the most commonly used methods generate a heterogeneous nanocrystalline material. Thus, it is likely that such aggregates do not resemble to PHZ and differ in their inflammatory properties. To address this issue, the present study was designed to establish whether synthetic HZ (sHZ) crystals produced by different methods vary in their morphology and in their ability to activate immune responses. We report a new method of HZ synthesis (the precise aqueous acid-catalyzed method) that yields homogeneous sHZ crystals (Plasmodium-like HZ) which are very similar to PHZ in their size and physicochemical properties. Importantly, these crystals are devoid of protein and DNA contamination. Of interest, structure-function studies revealed that the size and shape of the synthetic crystals influences their ability to activate inflammatory responses (e.g. nitric oxide, chemokine and cytokine mRNA) in vitro and in vivo. In summary, our data confirm that sHZ possesses immunostimulatory properties and underline the importance of verifying by electron microscopy both the morphology and homogeneity of the synthetic crystals to ensure that they closely resemble those of the parasite. Periodic quality control experiments and unification of the method of HZ synthesis are key steps to unravel the role of HZ in malaria immunopathology
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