52,108 results match your criteria model explain


Model-as-replica, model-as-instrument: Representational power and contextual versatility in animal models.

Authors:
Bican Polat

Stud Hist Philos Sci 2021 Jul 26;89:19-30. Epub 2021 Jul 26.

Tsinghua-Michigan Society of Fellows, Tsinghua University, Haidian, Beijing, 100084, China. Electronic address:

Existing scholarship on animal models tends to foreground either of the two major roles research organisms play in different epistemic contexts, treating their representational and instrumental roles separately. Based on an empirical case study, this article explores the changing relationship between the two epistemic roles of a research organism over the span of a decade, while the organism was used to achieve various knowledge ends. This rat model was originally intended as a replica of human susceptibility to cardiac arrest. Read More

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An attentional perspective on differential fear conditioning in chronic pain: The informational value of safety cues.

Behav Res Ther 2021 Jun 29;144:103917. Epub 2021 Jun 29.

Department of Psychology, Universität Koblenz-Landau, Germany.

Differences in fear conditioning between individuals suffering from chronic pain and healthy controls may indicate a learning bias that contributes to the acquisition and persistence of chronic pain. However, evidence from lab-controlled conditioning studies is sparse and previous experiments have produced inconsistent findings. Twenty-five participants suffering from chronic back pain and twenty-five controls not reporting chronic pain took part in a differential fear conditioning experiment measuring attention (eye tracking) and autonomic arousal (pupil dilation and skin conductance) elicited by visual cues predicting the presence or absence of electric shock. Read More

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Indices of callosal axonal density and radius from diffusion MRI relate to upper and lower limb motor performance.

Neuroimage 2021 Jul 26:118433. Epub 2021 Jul 26.

Movement Control and Neuroplasticity Research Group, Department of Movement Sciences, KU Leuven, Leuven (3000), Belgium; LBI-KU Leuven Brain Institute, Leuven (3000), Belgium.

Understanding the relationship between human brain structure and functional outcome is of critical importance in systems neuroscience. Diffusion MRI (dMRI) studies show that fractional anisotropy (FA) is predictive of motor control, underscoring the importance of white matter (WM). However, as FA is a surrogate marker of WM, we aim to shed new light on the structural underpinnings of this relationship by applying a multi-compartment microstructure model providing axonal density/radius indices. Read More

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Predicting individual neuron responses with anatomically constrained task optimization.

Curr Biol 2021 Jul 28. Epub 2021 Jul 28.

Department of Molecular Cellular and Developmental Biology, Yale University, New Haven, CT 06511, USA; Department of Neuroscience, Yale University, New Haven, CT 06511, USA; Interdepartmental Neuroscience Program, Yale University, New Haven, CT 06511, USA; Department of Physics, Yale University, New Haven, CT 06511, USA. Electronic address:

Artificial neural networks trained to solve sensory tasks can develop statistical representations that match those in biological circuits. However, it remains unclear whether they can reproduce properties of individual neurons. Here, we investigated how artificial networks predict individual neuron properties in the visual motion circuits of the fruit fly Drosophila. Read More

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Deep ancestral introgression shapes evolutionary history of dragonflies and damselflies.

Syst Biol 2021 Jul 29. Epub 2021 Jul 29.

Department of Biology, Brigham Young University, Provo, UT, United States.

Introgression is an important biological process affecting at least 10% of the extant species in the animal kingdom. Introgression significantly impacts inference of phylogenetic species relationships where a strictly binary tree model cannot adequately explain reticulate net-like species relationships. Here we use phylogenomic approaches to understand patterns of introgression along the evolutionary history of a unique, non-model insect system: dragonflies and damselflies (Odonata). Read More

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Structuro-functional surrogates of response to subcallosal cingulate deep brain stimulation for depression.

Brain 2021 Jul 29. Epub 2021 Jul 29.

Division of Neurosurgery, Department of Surgery, University Health Network and University of Toronto, Toronto, M5T 2S8, Canada.

Subcallosal cingulate deep brain stimulation (SCC-DBS) produces long-term clinical improvement in approximately half of patients with severe treatment-resistant depression (TRD). We hypothesized that both structural and functional brain attributes may be important in determining responsiveness to this therapy. In a TRD SCC-DBS cohort, we retrospectively examined baseline and longitudinal differences in MRI-derived brain volume (n = 65) and 18F-fluorodeoxyglucose-PET glucose metabolism (n = 21) between responders and non-responders. Read More

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Explainable models for forecasting the emergence of political instability.

PLoS One 2021 29;16(7):e0254350. Epub 2021 Jul 29.

Independent Researcher, Tallinn, Harjumaa, Estonia.

Building on previous research on the use of macroeconomic factors for conflict prediction and using data on political instability provided by the Political Instability Task Force, this article proposes two minimal forecasting models of political instability optimised to have the greatest possible predictive power for one-year and two-year event horizons, while still making predictions that are fully explainable. Both models employ logistic regression and use just three predictors: polity code (a measure of government type), infant mortality, and years of stability (i.e. Read More

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Are "GAPT Charges" Really Just Charges?

J Chem Inf Model 2021 Jul 29. Epub 2021 Jul 29.

Institute of Chemistry, State University of Campinas, Campinas 13083-861, SP, Brazil.

Generalized atomic polar tensor (GAPT) has turned into a very popular charge model since it was proposed three decades ago. During this period, several works aiming to compare different partition schemes have included it among their tested models. Nonetheless, GAPT exhibits a set of unique features that prevent it from being directly comparable to "standard" partition schemes. Read More

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On the variability of motor-evoked potentials: experimental results and mathematical model.

Authors:
Charles Capaday

Exp Brain Res 2021 Jul 29. Epub 2021 Jul 29.

Department of Health and Human Physiology, Motor Control Laboratories, University of Iowa, Iowa City, IA, 52242, USA.

The purpose of this study was to determine the form of the relation between the mean amplitude and variance of motor-evoked potentials (MEP). To this end, single-pulse transcranial magnetic stimulation (TMS) was applied over the motor cortex of seventeen neurologically normal adult human subjects. The coil was positioned at a locus on the scalp that elicited an MEP in the first dorsal interosseous (FDI) at the lowest stimulus intensity. Read More

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Insights on the coupling between vibronically active molecular vibrations and lattice phonons in molecular nanomagnets.

Dalton Trans 2021 Jul 29. Epub 2021 Jul 29.

Instituto de Ciencia Molecular, Universitat de València, Catedrático José Beltrán Martínez, 2, Paterna 46980, Spain.

Spin-lattice relaxation is a key open problem to understand the spin dynamics of single-molecule magnets and molecular spin qubits. While modelling the coupling between spin states and local vibrations allows to determine the more relevant molecular vibrations for spin relaxation, this is not sufficient to explain how energy is dissipated towards the thermal bath. Herein, we employ a simple and efficient model to examine the coupling of local vibrational modes with long-wavelength longitudinal and transverse phonons in the clock-like spin qubit [Ho(W5O18)2]9-. Read More

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An introduction to model implied instrumental variables using two stage least squares (MIIV-2SLS) in structural equation models (SEMs).

Psychol Methods 2021 Jul 29. Epub 2021 Jul 29.

Department of Psychology and Neuroscience, University of North Carolina at Chapel Hill.

Structural equation models (SEMs) are widely used to handle multiequation systems that involve latent variables, multiple indicators, and measurement error. Maximum likelihood (ML) and diagonally weighted least squares (DWLS) dominate the estimation of SEMs with continuous or categorical endogenous variables, respectively. When a model is correctly specified, ML and DWLS function well. Read More

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The impact of the COVID-19 pandemic on gender-based violence in the United States: Framework and policy recommendations.

Psychol Trauma 2021 Jul 29. Epub 2021 Jul 29.

Department of Psychology.

Objective: In response to the 2019 novel coronavirus pandemic, portions of the U.S. government implemented social distancing policies that, while necessary, yield unintended consequences. Read More

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Low Dose Hyperoxia Primes Airways for Fibrosis in Mice after Influenza A Infection.

Am J Physiol Lung Cell Mol Physiol 2021 Jul 29. Epub 2021 Jul 29.

Department of Pediatrics, grid.16416.34University of Rochester, Rochester, NY, United States.

It is well known that supplemental oxygen used to treat preterm infants in respiratory distress is associated with permanently disrupting lung development and the host response to influenza A virus (IAV). However, many infants who go home with normally functioning lungs are also at risk for hyperreactivity after a respiratory viral infection. We recently reported a new, low-dose hyperoxia mouse model (40% for 8 days; 40x8) that causes a transient change in lung function that resolves, rendering 40x8 adult animals functionally indistinguishable from room air controls. Read More

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Construction data mining methods in the prediction of death in hemodialysis patients using support vector machine, neural network, logistic regression and decision tree.

J Prev Med Hyg 2021 Mar 29;62(1):E222-E230. Epub 2021 Apr 29.

Department of Health Management and Economics, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran.

Objectives: Chronic kidney disease (CKD) is one of the main causes of morbidity and mortality worldwide. Detecting survival modifiable factors could help in prioritizing the clinical care and offers a treatment decision-making for hemodialysis patients. The aim of this study was to develop the best predictive model to explain the predictors of death in Hemodialysis patients by data mining techniques. Read More

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Diagnosis of Acute Central Dizziness With Simple Clinical Information Using Machine Learning.

Front Neurol 2021 12;12:691057. Epub 2021 Jul 12.

Department of Neurology, Asan Medical Center, University of Ulsan, College of Medicine, Seoul, South Korea.

Acute dizziness is a common symptom among patients visiting emergency medical centers. Extensive neurological examinations aimed at delineating the cause of dizziness often require experience and specialized training. We tried to diagnose central dizziness by machine learning using only basic clinical information. Read More

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Baicalin Alleviates Oxidative Stress and Inflammation in Diabetic Nephropathy via Nrf2 and MAPK Signaling Pathway.

Drug Des Devel Ther 2021 21;15:3207-3221. Epub 2021 Jul 21.

Institute of Integrated Traditional Chinese and Western Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, People's Republic of China.

Background: Oxidative stress and inflammation play essential roles in the development and progression of diabetic nephropathy (DN). Baicalin (BAI), a natural flavonoid, has been showed to have a renoprotective effect in various renal diseases. However, its underlying mechanisms in DN remain unclear. Read More

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Behavior Change Communication: Past, Present, and Future.

Indian J Community Med 2021 Apr-Jun;46(2):186-190. Epub 2021 May 29.

Department of Community Medicine, Sri Manakula Vinayagar Medical College and Hospital, Puducherry, India.

Behavior change communication (BCC) aids in the prevention of both communicable and noncommunicable diseases in clinical settings and public health. Emerging and re-emerging infectious diseases in the future need to be tackled by developing behavioral immunity through effective BCC strategies. Health education and Information Education and Communication gradually evolved to BCC primarily focusing on creating a conducive environment for promoting behavior change. Read More

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Drug transport kinetics of intravascular triggered drug delivery systems.

Commun Biol 2021 Jul 28;4(1):920. Epub 2021 Jul 28.

Department of Pediatrics, Medical University of South Carolina, Charleston, SC, USA.

Intravascular triggered drug delivery systems (IV-DDS) for local drug delivery include various stimuli-responsive nanoparticles that release the associated agent in response to internal (e.g., pH, enzymes) or external stimuli (e. Read More

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An anatomically constrained model of V1 simple cells predicts the coexistence of push-pull and broad inhibition.

J Neurosci 2021 Jul 28. Epub 2021 Jul 28.

Faculty of Mathematics and Physics, Charles University, Prague, 11800, Czechia.

The spatial organization and dynamic interactions between excitatory and inhibitory synaptic inputs that define the receptive field (RF) of simple cells in cat primary visual cortex (V1) still raise paradoxical issues: 1) stimulation of simple cells in V1 with drifting gratings supports a wiring schema of spatially segregated sets of excitatory and inhibitory inputs activated in an opponent way by stimulus contrast polarity; 2) in contrast, intracellular studies using flashed bars suggest that, while ON and OFF excitatory input are indeed segregated, inhibitory inputs span the entire RF irrespective of input contrast polarity. Here, we propose a biologically detailed computational model of simple cells embedded in a V1-like network that resolves this seeming contradiction. We varied parametrically the RF-correlation-based bias for excitatory and inhibitory synapses and found that a moderate bias of excitatory neurons to synapse onto other neurons with correlated receptive fields, and a weaker bias of inhibitory neurons to synapse onto other neurons with anti-correlated receptive fields can explain the conductance input, the postsynaptic membrane potential, and the spike train dynamics under both stimulation paradigms. Read More

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An explainable supervised machine learning predictor of acute kidney injury after adult deceased donor liver transplantation.

J Transl Med 2021 Jul 28;19(1):321. Epub 2021 Jul 28.

Department of Anesthesiology, The Third Affiliated Hospital of Sun Yat-Sen University, No. 600 Tianhe Road, Guangzhou, Guangdong, China.

Background: Early prediction of acute kidney injury (AKI) after liver transplantation (LT) facilitates timely recognition and intervention. We aimed to build a risk predictor of post-LT AKI via supervised machine learning and visualize the mechanism driving within to assist clinical decision-making.

Methods: Data of 894 cases that underwent liver transplantation from January 2015 to September 2019 were collected, covering demographics, donor characteristics, etiology, peri-operative laboratory results, co-morbidities and medications. Read More

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Prophylactic Application of Tailocins Prevents Infection by Pseudomonas syringae.

Phytopathology 2021 Jul 28. Epub 2021 Jul 28.

University of Arizona, Plant Sciences, Tucson, Arizona, United States;

Tailocins are phage-derived bacteriocins that demonstrate great potential as agricultural antimicrobials given their high killing efficiency and their precise strain-specific targeting ability. Our group has recently categorized and characterized tailocins produced by and tailocin sensitivities of the phytopathogen Pseudomonas syringae, and here we extend these experiments to test whether prophylactic tailocin application can prevent infection of Nicotiana benthamiana by P. syringae pv. Read More

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Simulation of Negative Ion Photoelectron Spectroscopy Using a Nuclear Ensemble Approach: Implications from a Nuclear Vibration Effect.

J Phys Chem A 2021 Jul 28. Epub 2021 Jul 28.

State Key Laboratory of Precision Spectroscopy, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, P. R. China.

The negative ion photoelectron spectroscopy (NIPES) has been proven to be a powerful technique to reveal the electronic structures and spectroscopic properties of various cluster anions/radicals with very high precision. However, direct comparisons of the theoretical NIPES with experimental measurements remain challenging. Particularly the nuclear vibration effect and the ionization probability are typically ignored in reproducing NIPES. Read More

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Time series data analysis and ARIMA modeling to forecast the short-term trajectory of the acceleration of fatalities in Brazil caused by the corona virus (COVID-19).

PeerJ 2021 15;9:e11748. Epub 2021 Jul 15.

Department of Mathematics and Statistics, Faculty of Science and Technology, University of the West Indies St. Augustine, Port of Spain, Trinidad and Tobago.

Objective: This paper incorporates the concept of acceleration to fatalities caused by the coronavirus in Brazil from time series data beginning on 17 March 2020 (the day of the first death) to 3 February 2021 to explain the trajectory of the fatalities for the next six months using confirmed infections as the explanatory variable.

Methods: Acceleration of the cases of confirmed infection and fatalities were calculated by using the concept of derivatives. Acceleration of fatality function was then determined from multivariate linear function and calculus chain rule for composite function with confirmed infections as an explanatory variable. Read More

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Effect of Ethanol and Ultrasound Pretreatments on Pineapple Convective Drying.

Food Technol Biotechnol 2021 Jun;59(2):209-215

Federal University of Pernambuco, Department of Chemical Engineering, Av. Prof. Arthur de Sá, s/n, Cidade Universitária, Recife-PE, 50740-521, Brazil.

Research Background: Drying represents a viable unit operation for the preservation of food. Convective drying is the most used method for plant materials. However, it can result in negative changes in food nutrient composition, and other quality parameters, besides requiring high energy consumption. Read More

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Rabphilin silencing causes dilated cardiomyopathy in a Drosophila model of nephrocyte damage.

Sci Rep 2021 Jul 27;11(1):15287. Epub 2021 Jul 27.

INCLIVA Biomedical Research Institute, 46010, Valencia, Spain.

Heart failure (HF) and the development of chronic kidney disease (CKD) have a direct association. Both can be cause and consequence of the other. Many factors are known, such as diabetes or hypertension, which can lead to the appearance and/or development of these two conditions. Read More

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Interactive Metal Mixture Toxicity to Daphnia magna Populations as an Emergent Property in a Dynamic Energy Budget Individual-Based Model.

Environ Toxicol Chem 2021 Jul 27. Epub 2021 Jul 27.

Laboratory of Environmental Toxicology and Aquatic Ecology, Environmental Toxicology Unit (GhEnToxLab), Ghent University, Coupure Links 653 Building F - 2nd Floor, 9000, Ghent, Belgium.

Environmental risk assessment of metal mixtures is challenging due to the large number of possible mixtures and interactions. Mixture toxicity data cannot realistically be generated for all relevant scenarios. Therefore, methods for prediction of mixture toxicity from single-metal toxicity data are needed. Read More

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Computational Fluid Dynamics of Intraocular Silicone Oil Tamponade.

Transl Vis Sci Technol 2021 Jul;10(8):22

IRCCS Fondazione G.B. Bietti ONLUS.

Purpose: To investigate the behavior of silicone oil (SiO) at the steady equilibrium and during saccades and calculate SiO-retina contact, shear stress (SS), and shear rate (SR).

Methods: A 24 mm phakic eye mesh model underwent 50°/0.137s saccade. Read More

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Adjustment for energy intake in nutritional research: a causal inference perspective.

Am J Clin Nutr 2021 Jul 27. Epub 2021 Jul 27.

Leeds Institute for Data Analytics, University of Leeds, Leeds, LS2 9NL, UK.

Background: Four models are commonly used to adjust for energy intake when estimating the causal effect of a dietary component on an outcome; 1) the "standard model" adjusts for total energy intake, 2) the "energy partition model" adjusts for remaining energy intake, 3) the "nutrient density model" rescales the exposure as a proportion of total energy, and 4) the "residual model" indirectly adjusts for total energy by using a residual. It remains underappreciated that each approach evaluates a different estimand and only partially accounts for confounding by common dietary causes.

Objective: To clarify the implied causal estimand and interpretation of each model and evaluate their performance in reducing dietary confounding. Read More

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The absorption and multiplication of uncertainty in machine-learning-driven finance.

Br J Sociol 2021 Jul 27. Epub 2021 Jul 27.

Department of Management, Politics and Philosophy, Copenhagen Business School, Frederiksberg, Denmark.

Uncertainty about market developments and their implications characterize financial markets. Increasingly, machine learning is deployed as a tool to absorb this uncertainty and transform it into manageable risk. This article analyses machine-learning-based uncertainty absorption in financial markets by drawing on 182 interviews in the finance industry, including 45 interviews with informants who were actively applying machine-learning techniques to investment management, trading, or risk management problems. Read More

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Ultrametric diffusion equation on energy landscape to model disease spread in hierarchic socially clustered population.

Physica A 2021 Jul 21:126284. Epub 2021 Jul 21.

Linnaeus University, International Center for Mathematical Modeling in Physics and Cognitive Sciences Växjö, SE 351 95, Sweden.

We present a new mathematical model of disease spread reflecting some specialties of the covid-19 epidemic by elevating the role of hierarchic social clustering of population. The model can be used to explain slower approaching herd immunity, e.g. Read More

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