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Jing Qian, Sy Han Chiou, Jacqueline E Maye, Folefac Atem, Keith A Johnson, Rebecca A Betensky
In several common study designs, regression modeling is complicated by the presence of censored covariates. Examples of such covariates include maternal age of onset of dementia that may be right censored in an Alzheimer's amyloid imaging study of healthy subjects, metabolite measurements that are subject to limit of detection censoring in a case-control study of cardiovascular disease, and progressive biomarkers whose baseline values are of interest, but are measured post-baseline in longitudinal neuropsychological studies of Alzheimer's disease...
June 22, 2018: Biometrics
Marius Galabe Sampid, Haslifah M Hasim, Hongsheng Dai
In this paper, we propose a model for forecasting Value-at-Risk (VaR) using a Bayesian Markov-switching GJR-GARCH(1,1) model with skewed Student's-t innovation, copula functions and extreme value theory. A Bayesian Markov-switching GJR-GARCH(1,1) model that identifies non-constant volatility over time and allows the GARCH parameters to vary over time following a Markov process, is combined with copula functions and EVT to formulate the Bayesian Markov-switching GJR-GARCH(1,1) copula-EVT VaR model, which is then used to forecast the level of risk on financial asset returns...
2018: PloS One
Encarnación Castillo, Diego P Morales, Antonio García, Luis Parrilla, Víctor U Ruiz, José A Álvarez-Bermejo
Non-invasive fetal electrocardiography (ECG) is based on the acquisition of signals from abdominal surface electrodes. The composite abdominal signal consists of the maternal electrocardiogram along with the fetal electrocardiogram and other electrical interferences. These recordings allow for the acquisition of valuable and reliable information that helps ensure fetal well-being during pregnancy. This paper introduces a procedure for fetal heart rate extraction from a single-channel abdominal ECG signal. The procedure is composed of three main stages: a method based on wavelet for signal denoising, a new clustering-based methodology for detecting fetal QRS complexes, and a final stage to correct false positives and false negatives...
2018: PloS One
Sidney C Silva, Walace D Monteiro, Felipe A Cunha, Paulo Farinatti
Silva, SC, Monteiro, WD, Cunha, FA, and Farinatti, P. Influence of different treadmill inclinations on V[Combining Dot Above]O2max and ventilatory thresholds during maximal ramp protocols. J Strength Cond Res XX(X): 000-000, 2018-Ramp protocols for cardiopulmonary exercise testing (CPET) lack precise recommendations, including optimal treadmill inclination. This study investigated the impact of treadmill grades applied in ramp CPETs on maximal oxygen uptake (V[Combining Dot Above]O2max), ventilatory thresholds (VT1/VT2), and V[Combining Dot Above]O2 vs...
June 21, 2018: Journal of Strength and Conditioning Research
Vitor de Salles Painelli, Kleiner Márcio Nemezio, Ana Jéssica, Mariana Franchi, Isabel Andrade, Luiz Augusto Riani, Bryan Saunders, Craig Sale, Roger Charles Harris, Bruno Gualano, Guilherme Giannini Artioli
PURPOSE: Cross-sectional studies suggest that training can increase muscle carnosine (MCarn), although longitudinal studies have failed to confirm this. A lack of control for dietary β-alanine intake or muscle fibre type shifting may have hampered their conclusions. The purpose of the present study was to investigate the effects of high-intensity interval training (HIIT) on MCarn. METHODS: Twenty vegetarian men were randomly assigned to a control (CON; n=10) or HIIT (n=10) group...
June 21, 2018: Medicine and Science in Sports and Exercise
Daiki Kato, Takashi Suto, Hideaki Obata, Shigeru Saito
BACKGROUND: Although endogenous analgesia plays an important role in controlling pain states, chronic pain patients exhibit decreased endogenous analgesia compared to healthy individuals. In rats, noxious stimulus-induced analgesia (NSIA), which is an indicator of endogenous analgesia, diminished 6 weeks after spinal nerve ligation (SNL6W). A recent study in rats with deleted noradrenergic fibers demonstrated that the noradrenergic fibers were essential to NSIA. It has also been reported that brain-derived neurotrophic factor increased spinal noradrenergic fibers...
June 20, 2018: Anesthesia and Analgesia
Sunil Kr Jha, T H Yoon, Zhaoqing Pan
The present study is based on the application of a multivariate statistical analysis approach for the selection of optimal descriptors of nanomaterials with the objective of robust qualitative modeling of their toxicity. A novel data mining protocol has been developed for the selection of an optimal subset of descriptors of nanomaterials by using the well-known multivariate method principal component analysis (PCA). The selected subsets of descriptors were validated for qualitative modeling of the toxicity of nanomaterials in the PC space...
June 18, 2018: Computers in Biology and Medicine
Arjan Boonman, Pazit Zadicario, Yael Mazon, Chen Rabi, David Eilam
A barn owl swooping down generated a quieter, almost silent, noise (acoustic impulses) compared to a louder noise generated by the owl when taking off. These acoustic impulses are at low frequencies which are below the auditory threshold to most rodents. Therefore, rodents are less likely to hear these noises of owl flight. A previous study revealed that rodents exhibit frantic response to an owl taking off (as opposed to their typical freezing response during owl attack). The frantic response could be the result of tactile reception of the air-puffs generated by the owl's wingbeats and may reduce the success in subsequent attacks...
June 19, 2018: Behavioural Processes
Louis Anthony Tony Cox
Sufficiently high and prolonged inhalation exposures to some respirable elongated mineral particles (REMPs), notably including amphibole asbestos fibers, can increase risk of inflammation-mediated diseases including malignant mesothelioma, pleural diseases, fibrosis, and lung cancer. Chronic inflammation involves ongoing activation of the NLRP3 inflammasome, which enables immune cells to produce potent proinflammatory cytokines IL-1β and IL-18. Reactive oxygen species (ROS) (in particular, mitochondrial ROS) contribute to NRLP3 activation via a well-elucidated mechanism involving oxidation of reduced thioredoxin and association of thioredoxin-interacting protein with NLRP3...
June 19, 2018: Toxicology and Applied Pharmacology
Ryan G Price, Smith Apisarnthanarax, Stephanie K Schaub, Matthew J Nyflot, Tobias R Chapman, Manuela Matesan, Hubert J Vesselle, Stephen R Bowen
We report on patient-specific quantitative changes in longitudinal sulfur colloid SPECT/CT as a function of regional radiation dose distributions to normal liver in a cohort of hepatocellular carcinoma patients. Dose-response thresholds and slopes varied with baseline liver function metrics, and extreme values were found in patients with fatal hepatotoxicity. Dose-response modeling of normal liver in individual HCC patients has potential to characterize in vivo radiosensitivity, identify high risk subgroups, and personalize treatment planning dose constraints...
June 19, 2018: International Journal of Radiation Oncology, Biology, Physics
Colette Ridehalgh, Oliver P Sandy-Hindmarch, Aninna B Schmid
Study Design Prospective, cross-sectional diagnostic accuracy study. Background Small nerve fiber degeneration (SFD) commonly occurs in patients with peripheral neuropathies, resulting in deterioration in nerve function. Currently, the gold standard to identify SFD is through skin biopsies. Simple clinical tests aim to identify SFD, but their validity remains unknown. Objectives To examine the validity of clinical tests to assess SFD using carpal tunnel syndrome (CTS) as a model system. Methods 107 participants (22 healthy, 85 with CTS) underwent pinprick testing over the index finger, and had cold and warm detection thresholds taken (CDT, WDT) using quantitative sensory testing (QST)...
June 22, 2018: Journal of Orthopaedic and Sports Physical Therapy
James Wright, Stewart Bruce-Low, Simon A Jobson
This study investigated the effect cadence has on the estimation of critical power (CP) and the finite work capacity (W') during the 3-minute all-out cycling test. Ten participants completed 8 tests: 1) an incremental test to calculate gas exchange threshold (GET), maximal aerobic power (MAP) and peak oxygen uptake (V̇O2peak ), 2-4) three time-to-exhaustion tests at 80, 100 and 105% MAP to calculate CP and W', 5-7) four 3-minute all-out tests to calculate end power (EP) and work done above EP (WEP) using cadences ranging from preferred -5 to preferred +10 rev·min-1 to set the fixed resistance...
June 22, 2018: Journal of Sports Sciences
Fouaz S Ayachi, Jean-Marc Drouet, Yvan Champoux, Catherine Guastavino
OBJECTIVES: In this article, we seek to determine how sensitive road cyclists are to vertical vibration transmitted while riding a road bicycle and to propose metrics for the evaluation of dynamic comfort. BACKGROUND: Road cyclists are exposed to random-type excitation due to road roughness. Vibration transmitted affects dynamic comfort. But how sensitive are cyclists to vibration level? What are the best metrics to measure the amount of vibration transmitted to cyclists? Previous studies used sinusoidal excitation with participants on rigid seats and measured acceleration...
June 1, 2018: Human Factors
João G Rosa, Thomas W Kephart
The superradiant instability can lead to the generation of extremely dense axion clouds around rotating black holes. We show that, despite the long lifetime of the QCD axion with respect to spontaneous decay into photon pairs, stimulated decay becomes significant above a minimum axion density and leads to extremely bright lasers. The lasing threshold can be attained for axion masses μ≳10^{-8}  eV, which implies superradiant instabilities around spinning primordial black holes with mass ≲0.01  M_{⊙}...
June 8, 2018: Physical Review Letters
G Semeghini, G Ferioli, L Masi, C Mazzinghi, L Wolswijk, F Minardi, M Modugno, G Modugno, M Inguscio, M Fattori
Self-bound quantum droplets are a newly discovered phase in the context of ultracold atoms. In this Letter, we report their experimental realization following the original proposal by Petrov [Phys. Rev. Lett. 115, 155302 (2015)PRLTAO0031-900710.1103/PhysRevLett.115.155302], using an attractive bosonic mixture. In this system, spherical droplets form due to the balance of competing attractive and repulsive forces, provided by the mean-field energy close to the collapse threshold and the first-order correction due to quantum fluctuations...
June 8, 2018: Physical Review Letters
Sufi Zafar, Christopher D'Emic, Ashish Jagtiani, Ernst Kratschmer, Xin Miao, Yu Zhu, Renee Mo, Norma Sosa, Hendrik F Hamann, Ghavam Shahidi, Heike Riel
Silicon nanowire field effect transistor (FET) sensors have demonstrated their ability for rapid and label free detection of proteins, nucleotide sequences, and viruses at ultralow concentrations with the potential to be a transformative diagnostic technology. Their nanoscale size gives them their unique ultralow detection ability but also makes their fabrication challenging with large sensor to sensor variations, thus limiting their commercial applications. In this work, a combined approach of nanofabrication, device simulation, materials and electrical characterization is applied towards identifying and improving fabrication steps that induce sensor to sensor variations...
June 22, 2018: ACS Nano
T Chang, J Xia, L Xu, X Wang, B Zhu, L Zhang, X Gao, Y Chen, J Li, H Gao
A genome-wide association study (GWAS) was conducted for two carcass traits in Chinese Simmental beef cattle. The experimental population consisted of 1301 individuals genotyped with the Illumina BovineHD SNP BeadChip (770K). After quality control, 671 990 SNPs and 1217 individuals were retained for the GWAS. The phenotypic traits included carcass weight and bone weight, which were measured after the cattle were slaughtered at 16 to 18 months of age. Three statistical models-a fixed polygene model, a random polygene model and a composite interval mapping polygene model-were used for the GWAS...
June 22, 2018: Animal Genetics
Jasper Wouters, Fabian Kloosterman, Alexander Bertrand
The process of grouping neuronal spikes in an extracellular recording according to their neuronal sources, is generally referred to as spike sorting. Currently, the use of spike sorting is mainly limited to an offline usage, where spikes are sorted after the data acquisition has been completed. In this paper, we propose a discriminative template matching algorithm for threshold-based spike sorting on high-density extracellular data. Such threshold-based spike sorting has a low and deterministic algorithmic delay, allowing for fast online spike sorting...
June 22, 2018: Journal of Neural Engineering
Mingdong Yu, Baohui Su, Xiaoxia Zhang
OBJECTIVES: Here, using rat model, we investigated the roles of gardenoside in the chronic constriction injury (CCI) of the ischiadic nerve. METHODS: Bennett and Xie's unilateral sciatic nerve CCI model was used in this study. A total of 60 rats were divided into control group (CN), sham group (Sham), CCI group, and gardenoside administrated CCI group. An aliquot of 5 mL gardenoside solution was administrated through gavage once per day for 14 d. Mechanical withdrawal threshold (MWT) and the thermal withdrawal latency (TWL) were detected...
June 22, 2018: Journal of Receptor and Signal Transduction Research
Caio Luiz Dos Santos, André Froes de Borja Reis, Paulo Mazzafera, José Laércio Favarin
Rice feeds 50% of the world’s population. Flooding is the most common irrigation system used for growing rice, a practice responsible for a large amount of water loss. Climate changes may affect water availability in irrigated agriculture, and it will be necessary to develop more sustainable irrigation practices. The aim of this work was to determine, in controlled conditions, the threshold when water potential begins to decrease plant growth. Two independent greenhouse experiments were conducted during middle summer and fall, in order to validate the results for high and low evapotranspiration conditions...
June 22, 2018: Plants (Basel, Switzerland)
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