128,783 results match your criteria residential mobility

Sexual Development and the Environment: Conclusions from 40 Years of Theory.

Sex Dev 2021 Jun 15:1-16. Epub 2021 Jun 15.

Institute for Applied Ecology, University of Canberra, Canberra, Australian Capital Territory, Australia.

In this review, we consider the insight that has been gained through theoretical examination of environmental sex determination (ESD) and thermolability - how theory has progressed our understanding of the ecological and evolutionary dynamics associated with ESD, the transitional pathways between different modes of sex determination, and the underlying mechanisms. Following decades of theory on the adaptive benefits of ESD, several hypotheses seem promising. These hypotheses focus on the importance of differential fitness (sex-specific effects of temperature on fitness) in generating selection for ESD, but highlight alternative ways differential fitness arises: seasonal impacts on growth, sex-specific ages of maturation, and sex-biased dispersal. Read More

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Evolution of an asymptomatic first stage of infection in a heterogeneous population.

J R Soc Interface 2021 Jun 16;18(179):20210175. Epub 2021 Jun 16.

Department of Molecular Biology, Princeton University, Princeton, NJ, USA.

Pathogens evolve different life-history strategies, which depend in part on differences in their host populations. A central feature of hosts is their population structure (e.g. Read More

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Is the diatom sex clock a clock?

J R Soc Interface 2021 Jun 16;18(179):20210146. Epub 2021 Jun 16.

Algorithmic Algebra and Discrete Mathematics, Institute of Mathematics, Faculty of Mathematics and Natural Sciences, University of Kassel, 34109 Kassel, Germany.

The unique life cycle of diatoms with continuous decreasing and restoration of the cell size leads to periodic fluctuations in cell size distribution and has been regarded as a multi-annual clock. To understand the long-term behaviour of a population analytically, generic mathematical models are investigated algebraically and numerically for their capability to describe periodic oscillations. Whereas the generally accepted simple concepts for the proliferation dynamics do not sustain oscillating behaviour owing to broadening of the size distribution, simulations show that a proposed limited lifetime of a newly synthesized cell wall slows down the relaxation towards a time-invariant equilibrium state to the order of a hundred thousand generations. Read More

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A dynamic, ensemble learning approach to forecast dengue fever epidemic years in Brazil using weather and population susceptibility cycles.

J R Soc Interface 2021 Jun 16;18(179):20201006. Epub 2021 Jun 16.

Computational Health Informatics Program, Boston Children's Hospital, Boston, MA 02115, USA.

Transmission of dengue fever depends on a complex interplay of human, climate and mosquito dynamics, which often change in time and space. It is well known that its disease dynamics are highly influenced by multiple factors including population susceptibility to infection as well as by microclimates: small-area climatic conditions which create environments favourable for the breeding and survival of mosquitoes. Here, we present a novel machine learning dengue forecasting approach, which, dynamically in time and space, identifies local patterns in weather and population susceptibility to make epidemic predictions at the city level in Brazil, months ahead of the occurrence of disease outbreaks. Read More

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BIO-LGCA: A cellular automaton modelling class for analysing collective cell migration.

PLoS Comput Biol 2021 Jun 15;17(6):e1009066. Epub 2021 Jun 15.

Centre for Information Services and High Performance Computing, Technische Universität Dresden, Dresden, Germany.

Collective dynamics in multicellular systems such as biological organs and tissues plays a key role in biological development, regeneration, and pathological conditions. Collective tissue dynamics-understood as population behaviour arising from the interplay of the constituting discrete cells-can be studied with on- and off-lattice agent-based models. However, classical on-lattice agent-based models, also known as cellular automata, fail to replicate key aspects of collective migration, which is a central instance of collective behaviour in multicellular systems. Read More

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The epidemiology of bacterial zoonoses in pastoral and dairy cattle in Cameroon, Central Africa.

Zoonoses Public Health 2021 Jun 15. Epub 2021 Jun 15.

Royal (Dick) School of Veterinary Studies and The Roslin Institute, University of Edinburgh, Easter Bush, Midlothian, UK.

Previous work identified that bacterial zoonoses (Brucella species, Coxiella burnetii and Leptospira hardjo) were present in Cameroonian pastoral cattle. To assess the characteristics of this zoonotic risk, we analyse seroprevalence of each pathogen and the associated management, herd and environmental factors in Cameroonian pastoral and dairy cattle. Cross-sectional samples included pastoralist herds in the Northwest Region (NWR n = 750) and Vina Division (VD n = 748) and small holder dairy herds in the NWR (n = 60). Read More

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Reducing phenotypic instabilities of a microbial population during continuous cultivation based on cell switching dynamics.

Biotechnol Bioeng 2021 Jun 15. Epub 2021 Jun 15.

Terra research and teaching centre, Microbial Processes and Interactions (MiPI), Gembloux Agro-Bio Tech, University of Liège, Gembloux, Belgium.

Predicting the fate of individual cells among a microbial population (i.e., growth, gene expression) remains a challenge, especially when this population is exposed to very dynamic environmental conditions, such as those encountered during continuous cultivation. Read More

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Investigation of patterns and dynamics of substance users: A long-term toxicology study on a sample of the Greek population between 2005 and 2019.

J Forensic Sci 2021 Jun 15. Epub 2021 Jun 15.

Laboratory of Forensic Sciences, Democritus University of Thrace - School of Medicine, Alexandroupolis, Greece.

The purpose of the present study is to investigate dynamics underlying drug abuse and identify statistical correlations/patterns of forensic findings and sociodemographic factors in a population of illicit substance users. The following long-term studies were conducted: (a) a retrospective autopsy cohort study on autopsy incidents with available toxicological screening results (N = 482) in investigation of any possible forensic associations of exposure to illicit drugs; and (b) a cross-sectional study on a sample of arrested drug law offenders with available toxicological screening results (N = 195) as well as cluster analysis in order to possibly identify user profiles. Although outside the scope of the present study, ethanol was generally considered to be the main substance of abuse, as more than half of the premature deaths reported tested positive on the ethanol toxicology screen. Read More

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Heuristic optimization of impeller sidewall gaps-based on the bees algorithm for a centrifugal blood pump by CFD.

Int J Artif Organs 2021 Jun 15:3913988211023773. Epub 2021 Jun 15.

Faculty of Engineering and Natural Science, Mechanical Engineering Department, Konya Technical University, Konya, Turkey.

Optimization studies on blood pumps that require complex designs are gradually increasing in number. The essential design criteria of centrifugal blood pump are minimum shear stress with maximal efficiency. The geometry design of impeller sidewall gaps (blade tip clearance, axial gap, radial gap) is highly effective with regard to these two criteria. Read More

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Mathematical modeling of COVID-19 in India and its states with optimal control.

Model Earth Syst Environ 2021 Jun 10:1-16. Epub 2021 Jun 10.

Division of Mathematics, School of Advanced Sciences, Vellore Institute of Technology, Chennai, India.

A pandemic is an epidemic spread over a huge geographical area. COVID-19 is such pandemic documented after 1918 flu pandemic. In this work, we frame a mathematical epidemic model taking inspiration from the classic SIR model and develop a compartmental model with ten compartments to study the coronavirus dynamics in India and three of its most affected states, namely, Maharashtra, Karnataka, and Tamil Nadu, with inclusion of factors related to face mask efficacy, contact tracing, and testing along with quarantine and isolation. Read More

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Probing competing relaxation pathways in malonaldehyde with transient X-ray absorption spectroscopy.

Chem Sci 2020 Mar 25;11(16):4180-4193. Epub 2020 Mar 25.

Department of Chemistry, The PULSE Institute, Stanford University Stanford CA 94305 USA

Excited-state intramolecular hydrogen transfer (ESIHT) is a fundamental reaction relevant to chemistry and biology. Malonaldehyde is the simplest example of ESIHT, yet only little is known experimentally about its excited-state dynamics. Several competing relaxation pathways have been proposed, including internal conversion mediated by ESIHT and C[double bond, length as m-dash]C torsional motion as well as intersystem crossing. Read More

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Unravelling the effect of (ε)-(carboxyethyl)lysine on the conformation, dynamics and aggregation propensity of α-synuclein.

Chem Sci 2020 Mar 10;11(12):3332-3344. Epub 2020 Mar 10.

Institut Universitari d'Investigació en Ciències de la Salut (IUNICS), Institut d'Investigació Sanitària Illes Balears (IdISBa), Departament de Química, Universitat de les Illes Balears Ctra. Valldemossa km 7.5 E-07122 Palma de Mallorca Spain +34 971 173426 +34 971 173491.

α-Synuclein (αS) aggregation is a hallmark in several neurodegenerative diseases. Among them, Parkinson's disease is highlighted, characterized by the intraneuronal deposition of Lewy bodies (LBs) which causes the loss of dopaminergic neurons. αS is the main component of LBs and in them, it usually contains post-translational modifications. Read More

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Cell dynamics in human villous trophoblast.

Hum Reprod Update 2021 Jun 14. Epub 2021 Jun 14.

Maternal and Fetal Health, University of Manchester, Manchester Academic Health Sciences Centre, St Mary's Hospital, Manchester, UK.

Background: Villous cytotrophoblast (vCTB) is a precursor cell population that supports the development of syncytiotrophoblast (vSTB), the high surface area barrier epithelium of the placental villus, and the primary interface between maternal and fetal tissue. In light of increasing evidence that the placenta can adapt to changing maternal environments or, under stress, can trigger maternal disease, we consider what properties of these cells empower them to exert a controlling influence on pregnancy progression and outcome.

Objective And Rationale: How are cytotrophoblast proliferation and differentiation regulated in the human placental villus to allow for the increasing demands of the fetal and environmental challenges and stresses that may arise during pregnancy?

Search Methods: PubMed was interrogated using relevant keywords and word roots combining trophoblast, villus/villous, syncytio/syncytium, placenta, stem, transcription factor (and the individual genes), signalling, apoptosis, autophagy (and the respective genes) from 1960 to the present. Read More

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Cardiac Biomarkers in Pediatrics: An Undervalued Resource.

Clin Chem 2021 Jun 14. Epub 2021 Jun 14.

CALIPER Program, Pediatric Laboratory Medicine, The Hospital for Sick Children, Toronto, ON, Canada.

Background: The clinical use of common cardiac biomarkers, such as brain natriuretic peptides and troponins, has traditionally been limited to adult populations in the assessment of heart failure and acute coronary syndrome, respectively. While many have discounted the value of these markers in pediatric populations, emerging evidence suggests they may be useful in the diagnosis and prognostication of many cardiac and noncardiac pathologies in neonates, children, and adolescents, and an increasing number of pediatric hospitals are routinely measuring cardiac markers in their clinical practice.

Content: This review summarizes and critically evaluates the current literature regarding the application of cardiac biomarkers for clinical decision-making in the pediatric population. Read More

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Utilizing Time-Resolved Protein-Induced Fluorescence Enhancement to Identify Stable Local Conformations One α-Synuclein Monomer at a Time.

J Vis Exp 2021 May 30(171). Epub 2021 May 30.

Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, Faculty of Mathematics & Science, The Edmond J. Safra Campus, The Hebrew University of Jerusalem; The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem;

Using spectroscopic rulers to track multiple conformations of single biomolecules and their dynamics have revolutionized the understanding of structural dynamics and its contributions to biology. While the FRET-based ruler reports on inter-dye distances in the 3-10 nm range, other spectroscopic techniques, such as protein-induced fluorescence enhancement (PIFE), report on the proximity between a dye and a protein surface in the shorter 0-3 nm range. Regardless of the method of choice, its use in measuring freely-diffusing biomolecules one at a time retrieves histograms of the experimental parameter yielding separate centrally-distributed sub-populations of biomolecules, where each sub-population represents either a single conformation that stayed unchanged within milliseconds, or multiple conformations that interconvert much faster than milliseconds, and hence an averaged-out sub-population. Read More

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Stress, physical activity, sedentary behavior, and resilience-The effects of naturalistic periods of elevated stress: A measurement-burst study.

Psychophysiology 2021 Jun 14:e13846. Epub 2021 Jun 14.

Curtin School of Allied Health, Curtin University, Perth, WA, Australia.

Stress is an important consideration for understanding why individuals take part in limited or no physical activity. The negative effects of stress on physical activity do not hold for everyone, so examinations of possible resilience resources that might protect individuals from the harmful effects of stress are required. Accordingly, we conducted a measurement-burst study with 53 university students over a 6-month period to examine the dynamics among stress, physical activity, sedentary behavior, and resilience resources. Read More

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Virologic features of SARS-CoV-2 infection in children.

medRxiv 2021 Jun 3. Epub 2021 Jun 3.

Harvard Medical School, Boston, MA, USA.

Background: Data on viral factors causing pediatric disease and guidance for pediatric-specific considerations have lagged behind adults throughout the COVID-19 pandemic. As COVID-19 infections and deaths increase in the pediatric population, characterization of SARS-CoV-2 viral dynamics in children would enable data-driven public health guidance.

Methods: Nasal swabs collected from children with COVID-19 were analyzed. Read More

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AIMTOR, a BRET Biosensor for Live Recording of mTOR Activity in Cell Populations and Single Cells.

Bio Protoc 2021 Apr 20;11(8):e3989. Epub 2021 Apr 20.

DMEM, University of Montpellier, INRAE, Montpellier, France.

Mammalian target of rapamycin (mTOR) controls many crucial cellular functions, including protein synthesis, cell size, energy metabolism, lysosome and mitochondria biogenesis, and autophagy. Consequently, deregulation of mTOR signaling plays a role in numerous pathological conditions such as cancer, metabolic disorders and neurological diseases. Developing new tools to monitor mTOR spatiotemporal activation is crucial to better understand its roles in physiological and pathological conditions. Read More

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Chess Not Checkers: Complexities Within the Myeloid Response to the Acute Kidney Injury Syndrome.

Front Med (Lausanne) 2021 26;8:676688. Epub 2021 May 26.

Division of Nephrology, Department of Medicine, Center for Immunity, Inflammation, and Regenerative Medicine, University of Virginia, Charlottesville, VA, United States.

Immune dysregulation in acute kidney injury (AKI) is an area of intense interest which promises to enhance our understanding of the disease and how to manage it. Macrophages are a heterogeneous and dynamic population of immune cells that carry out multiple functions in tissue, ranging from maintenance to inflammation. As key sentinels of their environment and the major immune population in the uninjured kidney, macrophages are poised to play an important role in the establishment and pathogenesis of AKI. Read More

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Increased insulin resistance in intensive care: longitudinal retrospective analysis of glycaemic control patients in a New Zealand ICU.

Ther Adv Endocrinol Metab 2021 31;12:20420188211012144. Epub 2021 May 31.

Department of Intensive Care, Christchurch Hospital, Christchurch, New Zealand.

Background: Critical care populations experience demographic shifts in response to trends in population and healthcare, with increasing severity and/or complexity of illness a common observation worldwide. Inflammation in critical illness impacts glucose-insulin metabolism, and hyperglycaemia is associated with mortality and morbidity. This study examines longitudinal trends in insulin sensitivity across almost a decade of glycaemic control in a single unit. Read More

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Mechanochemical synthesis of glycine oligomers in a virtual rotational diamond anvil cell.

Chem Sci 2020 Jul 27;11(30):7760-7771. Epub 2020 Jul 27.

Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory Livermore CA 94550 USA

Mechanochemistry of glycine under compression and shear at room temperature is predicted using quantum-based molecular dynamics (QMD) and a simulation design based on rotational diamond anvil cell (RDAC) experiments. Ensembles of high throughput semiempirical density functional tight binding (DFTB) simulations are used to identify chemical trends and bounds for glycine chemistry during rapid shear under compressive loads of up to 15.6 GPa. Read More

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Public opinion regarding government response to COVID-19: case study of a large commercial city in Nigeria.

Pan Afr Med J 2021 17;38:282. Epub 2021 Mar 17.

Department of Pharmaceutical Health Outcomes and Policy, University of Houston College of Pharmacy, Houston, Texas, USA.

Introduction: government measures to contain the COVID-19 pandemic cannot be effective without widespread compliance by the public. A greater understanding of citizens' perceptions of these measures can help government agencies adapt their strategies to boost compliance. We examined citizens' perceptions of government's measures to contain the COVID-19 pandemic and its implications on compliance using data from Onitsha city, Anambra State Nigeria. Read More

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Characteristics and Clinical Course of Adult in Patients with SARS-CoV-2 Pneumonia at High Altitude.

Can Respir J 2021 8;2021:5590879. Epub 2021 Jun 8.

Department of Pneumology, Hospital Universitario Mayor Méderi, Bogotá, Colombia.

Background: SARS-CoV-2 has spread worldwide with different dynamics in each region. We aimed to describe the clinical characteristics and to explore risk factors of death, critical care admission, and use of invasive mechanical ventilation in hospitalized patients with SARS-CoV-2 pneumonia in a high-altitude population living in Bogotá, Colombia.

Methods: We conducted a concurrent cohort study of adult patients with laboratory-confirmed SARS-CoV-2 pneumonia. Read More

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Modular Molecular Weaponry Plays a Key Role in Competition Within an Environmental Population.

Front Microbiol 2021 21;12:671092. Epub 2021 May 21.

Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada.

The type VI secretion system (T6SS) operons of contain extraordinarily diverse arrays of toxic effector and cognate immunity genes, which are thought to play an important role in the environmental lifestyle and adaptation of this human pathogen. Through the T6SS, proteinaceous "spears" tipped with antibacterial effectors are injected into adjacent cells, killing those not possessing immunity proteins to these effectors. Here, we investigate the T6SS-mediated dynamics of bacterial competition within a single environmental population of . Read More

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Trends in COVID-19 prevalence and mortality: A year in review.

Physica D 2021 Nov 7;425:132968. Epub 2021 Jun 7.

Yau Mathematical Sciences Centre, Tsinghua University, Beijing, China.

This paper introduces new methods to study the changing dynamics of COVID-19 cases and deaths among the 50 worst-affected countries throughout 2020. First, we analyse the trajectories and turning points of rolling mortality rates to understand at which times the disease was most lethal. We demonstrate five characteristic classes of mortality rate trajectories and determine structural similarity in mortality trends over time. Read More

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November 2021

Elucidation of the inhibitory activity of plant-derived SARS-CoV inhibitors and their potential as SARS-CoV-2 inhibitors.

J Biomol Struct Dyn 2021 Jun 14:1-13. Epub 2021 Jun 14.

Department of Biochemistry and Molecular Biology, Tejgaon College, National University, Gazipur, Bangladesh.

Several drugs are now being tested as possible therapies due to the necessity of treating SARS-CoV-2 infection. Although approved vaccines bring much hope, a vaccination program covering the entire global population will take a very long time, making the development of effective antiviral drugs an effective solution for the immediate treatment of this dangerous infection. Previous studies found that three natural compounds, namely, tannic acid, 3-isotheaflavin-3-gallate and theaflavin-3,3-digallate, are effective proteinase (3CL) inhibitors of SARS-CoV (IC <10 µM). Read More

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Pancreatobiliary Flow Dynamics: Association Between Bile and Pancreatic Juice Evaluated With Cine-Dynamic Magnetic Resonance Cholangiopancreatography Using Spatially Selective Inversion Recovery Pulse.

J Magn Reson Imaging 2021 Jun 13. Epub 2021 Jun 13.

Department of Radiology, Yamaguchi University Graduate School of Medicine, Ube, Japan.

Background: The physiological flow patterns and the reciprocal relationship between pancreatic juice and bile excretion dynamics have not been clearly elucidated by imaging.

Purpose: To assess the physiological flow patterns of bile and pancreatic juice simultaneously in order to clarify the pancreatobiliary flow dynamics using cine-dynamic magnetic resonance cholangiopancreatography (MRCP) with a spatial selective inversion recovery (IR) pulse.

Study Type: Retrospective. Read More

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Population dynamics in the Japanese Archipelago since the Pleistocene revealed by the complete mitochondrial genome sequences.

Sci Rep 2021 Jun 13;11(1):12018. Epub 2021 Jun 13.

Department of Legal Medicine, Toho University School of Medicine, Tokyo, Japan.

The Japanese Archipelago is widely covered with acidic soil made of volcanic ash, an environment which is detrimental to the preservation of ancient biomolecules. More than 10,000 Palaeolithic and Neolithic sites have been discovered nationwide, but few skeletal remains exist and preservation of DNA is poor. Despite these challenging circumstances, we succeeded in obtaining a complete mitogenome (mitochondrial genome) sequence from Palaeolithic human remains. Read More

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Desert and anthropogenic mixing dust deposition influences microbial communities in surface waters of the western Pacific Ocean.

Sci Total Environ 2021 May 28;791:148026. Epub 2021 May 28.

Graduate School of Bioresources, Mie University, 1577 Kurimamachiya, Tsu, Mie 514-8507, Japan.

The western Pacific Ocean is particularly affected by dust aerosols due to the transport of desert-natural sand and industrially derived particulate matter with aerodynamic diameter < 2.5 μm (PM2.5) from continental Asia. Read More

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Deconstructing the parasite multiplication rate of Plasmodium falciparum.

Trends Parasitol 2021 Jun 9. Epub 2021 Jun 9.

Center for Communicable Diseases Dynamics, Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA. Electronic address:

Epidemiological indicators describing population-level malaria transmission dynamics are widely used to guide policy recommendations. However, the determinants of malaria outcomes within individuals are still poorly understood. This conceptual gap partly reflects the fact that there are few indicators that robustly predict the trajectory of individual infections or clinical outcomes. Read More

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