733 research outputs found
Some remarks on the hyperelliptic moduli of genus 3
In 1967, Shioda \cite{Shi1} determined the ring of invariants of binary
octavics and their syzygies using the symbolic method. We discover that the
syzygies determined in \cite{Shi1} are incorrect. In this paper, we compute the
correct equations among the invariants of the binary octavics and give
necessary and sufficient conditions for two genus 3 hyperelliptic curves to be
isomorphic over an algebraically closed field , . For
the first time, an explicit equation of the hyperelliptic moduli for genus 3 is
computed in terms of absolute invariants.Comment: arXiv admin note: text overlap with arXiv:1209.044
Liquid Xenon Detectors for Positron Emission Tomography
PET is a functional imaging technique based on detection of annihilation
photons following beta decay producing positrons. In this paper, we present the
concept of a new PET system for preclinical applications consisting of a ring
of twelve time projection chambers filled with liquid xenon viewed by avalanche
photodiodes. Simultaneous measurement of ionization charge and scintillation
light leads to a significant improvement to spatial resolution, image quality,
and sensitivity. Simulated performance shows that an energy resolution of <10%
(FWHM) and a sensitivity of 15% are achievable. First tests with a prototype
TPC indicate position resolution <1 mm (FWHM).Comment: Paper presented at the International Nuclear Physics Conference,
Vancouver, Canada, 201
Unusual presentation of thyrotoxicosis as complete heart block and renal failure: a case report
<p>Abstract</p> <p>Introduction</p> <p>Thyrotoxicosis is a clinical entity often very difficult to diagnose without biochemical confirmation as its clinical features can be highly varied. The most common cardiac manifestations of thyrotoxicosis are resting sinus tachycardia, supraventricular tachycardia including atrial fibrillation and atrial flutter with or without cardiac failure. Bradycardia and atrio-ventricular conduction defects are very uncommon in thyrotoxicosis.</p> <p>Case presentation</p> <p>We report the case of a 59-year-old Caucasian man presenting with progressive weight loss, abnormal liver function, acute renal failure and complete heart block due to thyrotoxicosis.</p> <p>Conclusion</p> <p>Thyrotoxicosis should be considered as a possible diagnosis in patients with bradycardia and heart blocks associated with abnormal symptoms like weight loss. Nevertheless, the clinical, electrophysiological and biochemical abnormalities associated with thyrotoxicosis may be completely reversible restoring euthyroid state.</p
Recommended from our members
Utilisation and application of implementation science in complex suicide prevention interventions: A systematic review
Objectives
Little is known about how complex, multilevel, and multicomponent suicide prevention interventions work in real life settings. Understanding the methods used to systematically adopt, deliver, and sustain these interventions could ensure that they have the best chance of unfolding their full effect. This systematic review aimed to examine the application and extent of utilisation of implementation science in understanding and evaluating complex suicide prevention interventions.
Methods
The review adhered to updated PRISMA guidelines and was prospectively registered with PROSPERO (CRD42021247950). PubMed, CINAHL, PsycINFO, ProQuest, SCOPUS and CENTRAL were searched. All English-language records (1990–2022) with suicide and/or self-harm as the primary aims or targets of intervention were eligible. A forward citation search and a reference search further bolstered the search strategy. Interventions were considered complex if they consisted of three or more components and were implemented across two or more levels of socio-ecology or levels of prevention.
Results
One hundred thirty-nine records describing 19 complex interventions were identified. In 13 interventions, use of implementation science approaches, primarily process evaluations, was explicitly stated. However, extent of utilisation of implementation science approaches was found to be inconsistent and incomprehensive.
Limitations
The inclusion criteria, along with a narrow definition of complex interventions may have limited our findings.
Conclusion
Understanding the implementation of complex interventions is crucial for unlocking key questions about theory-practice knowledge translation. Inconsistent reporting and inadequate understanding of implementation processes can lead to loss of critical, experiential knowledge related to what works to prevent suicide in real world settings
Quantifying and identifying the overlapping community structure in networks
It has been shown that the communities of complex networks often overlap with
each other. However, there is no effective method to quantify the overlapping
community structure. In this paper, we propose a metric to address this
problem. Instead of assuming that one node can only belong to one community,
our metric assumes that a maximal clique only belongs to one community. In this
way, the overlaps between communities are allowed. To identify the overlapping
community structure, we construct a maximal clique network from the original
network, and prove that the optimization of our metric on the original network
is equivalent to the optimization of Newman's modularity on the maximal clique
network. Thus the overlapping community structure can be identified through
partitioning the maximal clique network using any modularity optimization
method. The effectiveness of our metric is demonstrated by extensive tests on
both the artificial networks and the real world networks with known community
structure. The application to the word association network also reproduces
excellent results.Comment: 9 pages, 7 figure
Challenges and New Approaches to Proving the Existence of Muscle Synergies of Neural Origin
Muscle coordination studies repeatedly show low-dimensionality of muscle activations for a wide variety of motor tasks. The basis vectors of this low-dimensional subspace, termed muscle synergies, are hypothesized to reflect neurally-established functional muscle groupings that simplify body control. However, the muscle synergy hypothesis has been notoriously difficult to prove or falsify. We use cadaveric experiments and computational models to perform a crucial thought experiment and develop an alternative explanation of how muscle synergies could be observed without the nervous system having controlled muscles in groups. We first show that the biomechanics of the limb constrains musculotendon length changes to a low-dimensional subspace across all possible movement directions. We then show that a modest assumption—that each muscle is independently instructed to resist length change—leads to the result that electromyographic (EMG) synergies will arise without the need to conclude that they are a product of neural coupling among muscles. Finally, we show that there are dimensionality-reducing constraints in the isometric production of force in a variety of directions, but that these constraints are more easily controlled for, suggesting new experimental directions. These counter-examples to current thinking clearly show how experimenters could adequately control for the constraints described here when designing experiments to test for muscle synergies—but, to the best of our knowledge, this has not yet been done
Knowledge-based energy functions for computational studies of proteins
This chapter discusses theoretical framework and methods for developing
knowledge-based potential functions essential for protein structure prediction,
protein-protein interaction, and protein sequence design. We discuss in some
details about the Miyazawa-Jernigan contact statistical potential,
distance-dependent statistical potentials, as well as geometric statistical
potentials. We also describe a geometric model for developing both linear and
non-linear potential functions by optimization. Applications of knowledge-based
potential functions in protein-decoy discrimination, in protein-protein
interactions, and in protein design are then described. Several issues of
knowledge-based potential functions are finally discussed.Comment: 57 pages, 6 figures. To be published in a book by Springe
The effects of theaflavin-enriched black tea extract on muscle soreness, oxidative stress, inflammation, and endocrine responses to acute anaerobic interval training: a randomized, double-blind, crossover study
<p>Abstract</p> <p>Background</p> <p>Muscle soreness and decreased performance often follow a bout of high-intensity exercise. By reducing these effects, an athlete can train more frequently and increase long-term performance. The purpose of this study is to examine whether a high-potency, black tea extract (BTE) alters the delayed onset muscle soreness (DOMS), oxidative stress, inflammation, and cortisol (CORT) responses to high-intensity anaerobic exercise.</p> <p>Methods</p> <p>College-age males (N = 18) with 1+ yrs of weight training experience completed a double-blind, placebo-controlled, crossover study. Subjects consumed the BTE (1,760 mg BTE·d<sup>-1</sup>) or placebo (PLA) for 9 days. Each subject completed two testing sessions (T1 & T2), which occurred on day 7 of the intervention. T1 & T2 consisted of a 30 s Wingate Test plus eight 10 s intervals. Blood samples were obtained before, 0, 30 & 60 min following the interval sessions and were used to analyze the total to oxidized glutathione ratio (GSH:GSSG), 8-isoprostane (8-iso), CORT, and interleukin 6 (IL-6) secretion. DOMS was recorded at 24 & 48 h post-test using a visual analog scale while BTE or PLA continued to be administered. Significance was set at <it>P < 0.05</it>.</p> <p>Results</p> <p>Compared to PLA, BTE produced significantly higher average peak power (<it>P = 0.013</it>) and higher average mean power (<it>P = 0.067</it>) across nine WAnT intervals. BTE produced significantly lower DOMS compared to PLA at 24 h post test (<it>P < 0.001</it>) and 48 h post test (<it>P < 0.001</it>). Compared to PLA, BTE had a slightly higher GSH:GSSG ratio at baseline which became significantly higher at 30 and 60 min post test (<it>P < 0.002</it>). AUC analysis revealed BTE to elicit significantly lower GSSG secretion (<it>P = 0.009</it>), significantly higher GSH:GSSG ratio (<it>P = 0.001</it>), and lower CORT secretion (<it>P = 0.078</it>) than PLA. AUC analysis did not reveal a significant difference in total IL-6 response (<it>P = 0.145</it>) between conditions.</p> <p>Conclusions</p> <p>Consumption of theaflavin-enriched black tea extract led to improved recovery and a reduction in oxidative stress and DOMS responses to acute anaerobic intervals. An improved rate of recovery can benefit all individuals engaging in high intensity, anaerobic exercise as it facilitates increased frequency of exercise.</p
Automatic annotation of experimentally derived, evolutionarily conserved post-translational modifications onto multiple genomes
New generation sequencing technologies have resulted in significant increases in the number of complete genomes. Functional characterization of these genomes, such as by high-throughput proteomics, is an important but challenging task due to the difficulty of scaling up existing experimental techniques. By use of comparative genomics techniques, experimental results can be transferred from one genome to another, while at the same time minimizing errors by requiring discovery in multiple genomes. In this study, protein phosphorylation, an essential component of many cellular processes, is studied using data from large-scale proteomics analyses of the phosphoproteome. Phosphorylation sites from Homo sapiens, Mus musculus and Drosophila melanogaster phosphopeptide data sets were mapped onto conserved domains in NCBI’s manually curated portion of Conserved Domain Database (CDD). In this subset, 25 phosphorylation sites are found to be evolutionarily conserved between the three species studied. Transfer of phosphorylation annotation of these conserved sites onto sequences sharing the same conserved domains yield 3253 phosphosite annotations for proteins from coelomata, the taxonomic division that spans H. sapiens, M. musculus and D. melanogaster. The method scales automatically, so as the amount of experimental phosphoproteomics data increases, more conserved phosphorylation sites may be revealed
A Preliminary Study on Robot-Assisted Ankle Rehabilitation for the Treatment of Drop Foot
This paper involves the use of a compliant ankle rehabilitation robot (CARR) for the treatment of drop foot. The robot has a bio-inspired design by employing four Festo Fluidic muscles (FFMs) that mimic skeletal muscles actuating three rotational degrees of freedom (DOFs). A trajectory tracking controller was developed in joint task space to track the predefined trajectory of the end effector. This controller was achieved by controlling individual FFM length based on inverse kinematics. Three patients with drop foot participated in a preliminary study to evaluate the potential of the CARR for clinical applications. Ankle stretching exercises along ankle dorsiflexion and plantarflexion (DP) were delivered for treating drop foot. All patients gave positive feedback in using this ankle robot for the treatment of drop foot, although some limitations exist. The proposed controller showed satisfactory accuracy in trajectory tracking, with all root mean square deviation (RMSD) values no greater than 0.0335 rad and normalized root mean square deviation (NRMSD) values less than 6.7%. These preliminary findings support the potentials of the CARR for clinical applications. Future work will investigate the effectiveness of the robot for treating drop foot on a large sample of subjects
- …