Read by QxMD icon Read

Mathematical modelling

Thorsten Tjardes, Markus Luecking
Introduction: To achieve the aim of zero preventable deaths on the battlefield a deeper understanding of uncontrolled hemorrhage from junctional or proximal extremity sources is mandatory. While tourniquet application to the extremities has drastically reduced morbidity and mortality, there is still room for improvement regarding the timing of tourniquet placement as the available evidence clearly points out a tight correlation between timing of tourniquet application and outcome. To save as many lives as possible the "point of no return" regarding the circulatory breakdown due to hemorrhage, colloquially addressed as platinum 5 min, needs to be determined...
March 14, 2018: Military Medicine
María José Garcés Hernández, Miguel Klünder, Nayely Garibay Nieto, Juan Carlos López Alvarenga, Jenny Vilchis Gil, Samuel Flores Huerta, Rosa Quispe Siccha, Joselin Hernandez
OBJECTIVE: Visceral adiposity index (VAI) is a mathematical model associated with cardiometabolic risk in adults, but studies on children failed to support this association. Our group has proposed a pediatric VAI model using pediatric ranges, but it has not yet been evaluated and needs further adjustments. The objective of this study was to further adjust the proposed pediatric VAI by age, creating a new pediatric metabolic index (PMI), and assess the correlation of the PMI with insulin resistance indexes and hepatic enzymes...
March 2018: Endocrine Practice
Mirjana Miskovic, Dragan Ravanic, Dragic Bankovic, Nera Zivlak-Radulovic, Visnja Banjac, Tatjana Dragisic
INTRODUCTION: Cloninger's psychological model of temperament and character confirms that the personality development is influenced by biological and psychological processes. The aim of this study is to examine personality dimensions and to determine which variable separates the healthy from the ill in the best way and could be a possible psychological marker for the presence of the illness. METHODS: This research included 152 subjects, 76 patients with schizophrenia and 76 healthy controls, selected on the basis of medical interviews, random population sampling model from a wider social community using the independent T-Tests...
March 2018: Psychiatria Danubina
Bryce E Hughes
Using a national longitudinal survey data set from the Higher Education Research Institute, this study tested whether students who identified as a sexual minority (for example, lesbian, gay, bisexual, or queer) were more or less likely to persist after 4 years in science, technology, engineering, and mathematics (STEM) fields, as opposed to switching to a non-STEM program, compared to their heterosexual peers. A multilevel regression model controlling for various experiences and characteristics previously determined to predict retention in STEM demonstrated that, net of these variables, sexual minority students were 8% less likely to be retained in STEM compared to switching into a non-STEM program...
March 2018: Science Advances
Marinho A Lopes, Mark P Richardson, Eugenio Abela, Christian Rummel, Kaspar Schindler, Marc Goodfellow, John R Terry
Recent studies have shown that mathematical models can be used to analyze brain networks by quantifying how likely they are to generate seizures. In particular, we have introduced the quantity termed brain network ictogenicity (BNI), which was demonstrated to have the capability of differentiating between functional connectivity (FC) of healthy individuals and those with epilepsy. Furthermore, BNI has also been used to quantify and predict the outcome of epilepsy surgery based on FC extracted from pre-operative ictal intracranial electroencephalography (iEEG)...
2018: Frontiers in Neurology
Eduardo Massad, Marcos Amaku, Francisco Antonio Bezerra Coutinho, Claudio José Struchiner, Marcelo Nascimento Burattini, Kamran Khan, Jing Liu-Helmersson, Joacim Rocklöv, Moritz U G Kraemer, Annelies Wilder-Smith
Given the speed of air travel, diseases even with a short viremia such as dengue can be easily exported to dengue naïve areas within 24 hours. We set out to estimate the risk of dengue virus introductions via travelers into Europe and number of secondary autochthonous cases as a result of the introduction. We applied mathematical modeling to estimate the number of dengue-viremic air passengers from 16 dengue-endemic countries to 27 European countries, taking into account the incidence of dengue in the exporting countries, travel volume and the probability of being viremic at the time of travel...
March 15, 2018: Scientific Reports
Ying Han, Zhenyu Lu, Zhenguang Du, Qi Luo, Sheng Chen
BACKGROUND AND OBJECTIVE: Bipolar disorder is often mis-diagnosed as unipolar depression in the clinical diagnosis. The main reason is that, different from other diseases, bipolarity is the norm rather than exception in bipolar disorder diagnosis. YinYang bipolar fuzzy set captures bipolarity and has been successfully used to construct a unified inference mathematical modeling method to bipolar disorder clinical diagnosis. Nevertheless, symptoms and their interrelationships are not considered in the existing method, circumventing its ability to describe complexity of bipolar disorder...
May 2018: Computer Methods and Programs in Biomedicine
Joseph Páez Chávez, Dirk Jungmann, Stefan Siegmund
The paper presents a comprehensive numerical study of mathematical models used to describe complex biological systems in the framework of integrated pest management. Our study considers two specific ecosystems that describe the application of control mechanisms based on pesticides and natural enemies, implemented in an impulsive and periodic manner, due to which the considered models belong to the class of impulsive differential equations. The present work proposes a numerical approach to study such type of models in detail, via the application of path-following (continuation) techniques for nonsmooth dynamical systems, via the novel continuation platform COCO (Dankowicz and Schilder)...
December 2018: Journal of Biological Dynamics
Wentao Jing, Mohsen Ramezani, Kun An, Inhi Kim
The path choice behavior of battery electric vehicle (BEV) drivers is influenced by the lack of public charging stations, limited battery capacity, range anxiety and long battery charging time. This paper investigates the congestion/flow pattern captured by stochastic user equilibrium (SUE) traffic assignment problem in transportation networks with BEVs, where the BEV paths are restricted by their battery capacities. The BEV energy consumption is assumed to be a linear function of path length and path travel time, which addresses both path distance limit problem and road congestion effect...
2018: PloS One
Alessandra Livigni, Laura O'Hara, Marta E Polak, Tim Angus, Derek W Wright, Lee B Smith, Tom C Freeman
A major endeavor of systems biology is the construction of graphical and computational models of biological pathways as a means to better understand their structure and function. Here, we present a protocol for a biologist-friendly graphical modeling scheme that facilitates the construction of detailed network diagrams, summarizing the components of a biological pathway (such as proteins and biochemicals) and illustrating how they interact. These diagrams can then be used to simulate activity flow through a pathway, thereby modeling its dynamic behavior...
April 2018: Nature Protocols
Suyoung Seo
This paper presents a method of modeling edge profiles with two blur parameters, and estimating and predicting those edge parameters with varying brightness combinations and camera-to-object distances (COD). First, the validity of the edge model is proven mathematically. Then, it is proven experimentally with edges from a set of images captured for specifically designed target sheets and with edges from natural images. Estimation of the two blur parameters for each observed edge profile is performed with a brute-force method to find parameters that produce global minimum errors...
June 2018: IEEE Transactions on Image Processing: a Publication of the IEEE Signal Processing Society
Kyung Duk Min, Sung Il Cho
BACKGROUND: The incidence rate of scrub typhus has been increasing in the Republic of Korea. Previous studies have suggested that this trend may have resulted from the effects of climate change on the transmission dynamics among vectors and hosts, but a clear explanation of the process is still lacking. In this study, we applied mathematical models to explore the potential factors that influence the epidemiology of tsutsugamushi disease. METHODS: We developed mathematical models of ordinary differential equations including human, rodent and mite groups...
March 19, 2018: Journal of Korean Medical Science
Veronika Lerche, Andreas Voss
The diffusion model (Ratcliff, 1978) is a mathematical model theorized to untangle different cognitive processes involved in binary decision tasks. To test the validity of the diffusion model parameters, several experimental validation studies have been conducted. In these studies, the validity of the threshold separation parameter was tested with speed-accuracy manipulations. Typically, this manipulation not only results in the expected effect on the threshold separation parameter but it also impacts nondecision time: Nondecision time is longer in the accuracy than in the speed condition...
March 14, 2018: Behavior Research Methods
Tatsuya Yamada, Makoto Nishiyama, Shigeyuki Oba, Henri Claver Jimbo, Kazushi Ikeda, Shin Ishii, Kyonsoo Hong, Yuichi Sakumura
Biological cells express intracellular biomolecular information to the extracellular environment as various physical responses. We show a novel computational approach to estimate intracellular biomolecular pathways from growth cone electrophysiological responses. Previously, it was shown that cGMP signaling regulates membrane potential (MP) shifts that control the growth cone turning direction during neuronal development. We present here an integrated deterministic mathematical model and Bayesian reversed-engineering framework that enables estimation of the molecular signaling pathway from electrical recordings and considers both the system uncertainty and cell-to-cell variability...
March 14, 2018: Scientific Reports
Yanle Guo, Min Zhang, Zhiguang Liu, Xiaofei Tian, Shugang Zhang, Chenhao Zhao, Hao Lu
Previous research into the synthesis of urea-formaldehyde fertilizers was mostly based on orthogonal experimental designs or single factor tests; this led to low precision for synthesis and relatively large ranges of parameters for these processes. To obtain mathematical response models for the synthesis of urea-formaldehyde fertilizers with different nitrogen release properties, a central composite design (CCD) of response surface methodology was used in our research to examine the effects of different reaction times, temperatures, and molar ratios on nitrogen insoluble in either hot or cold water...
March 14, 2018: Scientific Reports
Motohisa Osaka
There are some reports that sympathetic nerve activity (SNA) shows a characteristic pattern a few hours before the onset of lethal ventricular arrhythmias. If so, it could be possible to predict sudden cardiac death a few hours in advance of its occurrence. Recently, we reported that a previously unidentified V-trough of SNA is a potential precursor of lethal cardiac events by examining 24-hour ambulatory electrocardiograms in which such an event was recorded by chance. In contrast, the chaotic nature of heart rate variability has been noted recently from the viewpoint of nonlinear dynamics...
2018: Journal of Nippon Medical School, Nippon Ika Daigaku Zasshi
Michael A Irvine, Bernhard P Konrad, Warren Michelow, Robert Balshaw, Mark Gilbert, Daniel Coombs
Increasing HIV testing rates among high-risk groups should lead to increased numbers of cases being detected. Coupled with effective treatment and behavioural change among individuals with detected infection, increased testing should also reduce onward incidence of HIV in the population. However, it can be difficult to predict the strengths of these effects and thus the overall impact of testing. We construct a mathematical model of an ongoing HIV epidemic in a population of gay, bisexual and other men who have sex with men...
March 2018: Journal of the Royal Society, Interface
Stephen Smith, Neil Dalchau
Synthesizing a genetic network which generates stable Turing patterns is one of the great challenges of synthetic biology, but a significant obstacle is the disconnect between the mathematical theory and the biological reality. Current mathematical understanding of patterning is typically restricted to systems of two or three chemical species, for which equations are tractable. However, when models seek to combine descriptions of intercellular signal diffusion and intracellular biochemistry, plausible genetic networks can consist of dozens of interacting species...
March 2018: Journal of the Royal Society, Interface
Antonella Succurro, Oliver Ebenhöh
Understanding microbial ecosystems means unlocking the path toward a deeper knowledge of the fundamental mechanisms of life. Engineered microbial communities are also extremely relevant to tackling some of today's grand societal challenges. Advanced meta-omics experimental techniques provide crucial insights into microbial communities, but have been so far mostly used for descriptive, exploratory approaches to answer the initial 'who is there?' QUESTION: An ecosystem is a complex network of dynamic spatio-temporal interactions among organisms as well as between organisms and the environment...
March 14, 2018: Biochemical Society Transactions
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"