Three-body unitarity in the finite volume Mai, M.; Döring, M.
The European physical journal. A, Hadrons and nuclei,
12/2017, Letnik:
53, Številka:
12
Journal Article
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The physical interpretation of lattice QCD simulations, performed in a small volume, requires an extrapolation to the infinite volume. A method is proposed to perform such an extrapolation for ...three interacting particles at energies above threshold. For this, a recently formulated relativistic
3
→
3
amplitude based on the isobar formulation is adapted to the finite volume. The guiding principle is two- and three-body unitarity that imposes the imaginary parts of the amplitude in the infinite volume. In turn, these imaginary parts dictate the leading power-law finite-volume effects. It is demonstrated that finite-volume poles arising from the singular interaction, from the external two-body sub-amplitudes, and from the disconnected topology cancel exactly leaving only the genuine three-body eigenvalues. The corresponding quantization condition is derived for the case of three identical scalar-isoscalar particles and its numerical implementation is demonstrated.
Antimicrobial resistance (AMR) continues to exert a substantial toll on the global health and world economy and is now expected to be hidden by COVID-19 for a while. The wrong consumption of ...antibiotics during the COVID-19 pandemic will raise disastrous effects on AMR management and antibiotic stewardship programs. This is related to the concerns extrapolated due to an increase in mortality rates in patients with bacterial coinfections. Importantly, the immune system of COVID-19 patients in regions with high AMR may be fighting on two fronts altogether, the virus and MDR bacteria. Current control policies to manage AMR and prioritization of antibiotic stewardship plans are mandatory during this pandemic. This review aims to discuss the rising concerns of the excess use of antibiotics in COVID-19 patients highlighting the role of bacterial coinfections in these patients. Types of prescribed antibiotics and the development of antibiotic resistance is addressed as well.
The retina provides exquisitely sensitive vision that relies on the integrity of a uniquely vulnerable cell, the photoreceptor (PR). The genetic and mechanistic causes of retinal degeneration due to ...PR cell death--which occurs in conditions such as retinitis pigmentosa and age-related macular degeneration--are being successfully dissected. Over one hundred loci, some containing common variants but most containing rare variants, are implicated in the genetic architecture of this complex trait. This genetic heterogeneity results in equally diverse disease mechanisms that affect almost every aspect of PR function but converge on a common cell death pathway. Although genetic and mechanistic diversity creates challenges for therapy, some approaches--particularly gene-replacement therapy--are showing considerable promise.
Neurologists have highly observed a frequent increasing number of elderly patients with Alzheimer's disease (AD) without any relevant evidence of any genetic or known AD‐linked predisposing factors ...in the past few years. Those patients are characterized by continuous and irreversible neuron cells loss along with declined cognitive functions. Numerous studies have suggested that the exaggerated release of reactive oxygen species (ROS) within the brain may develop late‐onset neurodegenerative disorders, especially AD‐neuroinflammatory type. However, the central nervous system is vitally linked with whole‐brain chemical integrity and its related healthy state, the cascade by which ROS may result in AD's development has not been highly justified or even maintained. It is widely known that the brain consumes a vast amount of oxygen and is characterized by being rich in lipid polyunsaturated fatty acids content, explaining why it is a prone region to oxidative stress (OS) and ROS damage. The formed OS‐AD cytoskeletal protein aggregates can be considered a main predisposing factor for amyloid‐beta (Aβ) hallmarks precipitation. Herein, this review aims to provide a detailed information on how oxidative stress can play a pathogenic role in activating damage‐associated molecular patterns (DAMPs)–related toll‐like receptor‐4 inflammatory (TLR‐4) cascades resulting in the deposition of Aβ hallmarks in brain tissues ending with irreversible cognitive dysfunction. It also explains how microglia can be activated via ROS, which may significantly release several pro‐inflammatory cascades ending with general brain atrophy. Furthermore, different types of suggested antioxidant therapies will be discussed to combat AD‐related pathological disorders and hallmarks.
Many questionnaires have been developed to measure physical activity (PA), but an overview of the measurement properties of PA questionnaires is lacking. A summary of this information is useful for ...choosing the best questionnaire available. Therefore, the objective of this study was to evaluate and compare measurement properties of self-administered questionnaires assessing PA in adults. We searched MEDLINE, EMBASE and SportDiscus, using 'exercise', 'physical activity', 'motor activity' and 'questionnaire' as keywords. We included studies that evaluated the measurement properties of self-report questionnaires assessing PA. Article selection, data extraction and quality assessment were performed by two independent reviewers. The quality and results of the studies were evaluated using the Quality Assessment of Physical Activity Questionnaires (QAPAQ) checklist. Construct validity, reliability and responsiveness were rated as positive, negative or indeterminate, depending on the methods and results. We included 85 (versions of) questionnaires. Overall, the quality of the studies assessing measurement properties of PA questionnaires was rather poor. Information on content validity was mostly lacking. Construct validity was assessed in 76 of the questionnaires, mostly by correlations with accelerometer data, maximal oxygen uptake or activity diaries. Fifty-one questionnaires were tested for reliability. Only a few questionnaires had sufficient construct validity and reliability, but these need to be further validated. Responsiveness was studied for only two questionnaires and was poor. There is a clear lack of standardization of PA questionnaires, resulting in many variations of questionnaires. No questionnaire or type of questionnaire for assessing PA was superior and therefore could not be strongly recommended above others. In the future, more attention should be paid to the methodology of studies assessing measurement properties of PA questionnaires and the quality of reporting.
Current data on the prevalence of overweight and energy-balance behaviors among European children is necessary to inform overweight prevention interventions.
A school-based survey among 10-12 year ...old children was conducted in seven European countries using a standardized protocol. Weight, height, and waist circumference were measured; Engagement in physical activity, sedentary and dietary behaviors, and sleep duration were self-reported. Descriptive analyses were conducted, looking at differences according to country, gender, and parental education. 7234 children (52%girls; 11.6 ± 0.7 years) participated. 25.8% and 5.4% of boys, and 21.8% and 4.1% of girls were overweight (including obese) and obese (according to International Obesity Task Force criteria), respectively. Higher prevalence of overweight/obesity was observed in Greece, Hungary, Slovenia and Spain than in Belgium, Netherlands and Norway. Large differences between countries were found in intakes of sugar-sweetened beverages, breakfast, active transport, TV and computer time. More favorable overweight status and behavior patterns were found in girls than boys and in children of higher educated parents than in children of lower educated parents.
High levels and striking differences in overweight status and potential risk behaviors were found among schoolchildren across Europe.
Early childhood is a critical period for growth and development, yet the association with physical activity during this important period is unknown. The aim of this review is to critically summarize ...the evidence on the prospective associations between physical activity and health and development in children aged < 5 years.
A systematic search in three electronic databases (Pubmed, PsycINFO, and Sportdiscus) was conducted to identify prospective studies examining the associations between physical activity (all types; specified by quantity) and health indicators (body composition, cardiometabolic health, bone health and risks/harm) or development (motor, cognitive and social-emotional development) in young children (mean age < 5 years at baseline). Two independent researchers assessed the methodological quality using the 'Quality Assessment Tool for Quantitative Studies' (EPHPP). This tool covers eight quality criteria: selection bias, study design, confounders, blinding, data collection methods, withdrawals and drop-outs, intervention integrity and data-analysis.
Thirty-nine studies, predominantly conducted in preschoolers (ages 3-5 years), were included of which nine were rated as high methodological quality. There was moderate evidence for a positive association between physical activity and motor (n = 11 studies) and cognitive development (n = 10 studies) based on consistent findings from studies having low-to-moderate methodological quality. There was insufficient evidence for an association between physical activity and body composition (n = 15 studies), cardiometabolic health indicators (n = 7 studies), social-emotional development (n = 2 studies) and bone health (n = 2 studies) based on inconsistent findings from studies having weak-to-high methodological quality.
There is a need for more high-quality research in order to determine the dose-response relationship between physical activity and health and development in early childhood. Special attention should be paid to studies in children below the age of 3 years.
Accurate proxy-report questionnaires, adapted to the child's developmental stage, are required to monitor 24-h movement behaviors in young children, especially for large samples and low-resource ...settings.
This review aimed to summarize available studies evaluating measurement properties of proxy-report questionnaires assessing physical activity, sedentary behavior and/or sleep in children aged 0-5 years.
Systematic literature searches were carried out in the PubMed, Embase and SPORTDiscus databases, up to January 2021. For physical activity and sedentary behavior questionnaires this is a review update, whereas for sleep questionnaires we included all relevant studies published up to now. Studies had to evaluate at least one of the measurement properties of a proxy-report questionnaire assessing at least duration and/or frequency of physical activity, sedentary behavior and/or sleep in 0- to 5-year-old children. The COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) guideline was used to evaluate the quality of evidence.
Thirty-three studies were included, examining a total of 37 questionnaires. Ten questionnaires were designed for infants, two for toddlers, 11 for preschoolers, and 14 for a broader age range targeting multiple of these age groups. Twenty questionnaires assessed constructs of sleep, four assessed constructs of physical activity, two assessed screen behavior, five assessed constructs of both physical activity and sedentary behavior, and six assessed constructs of all 24-h movement behaviors. Content validity was evaluated for six questionnaires, structural validity for two, internal consistency for three, test-retest reliability for 16, measurement error for one, criterion validity for one, and construct validity for 26 questionnaires. None of the questionnaires were considered sufficiently valid and/or reliable for assessing one or more movement behaviors in 0- to 5-year-old children, and the quality of evidence was mostly low or very low.
Valid and/or reliable questionnaires assessing 24-h movement behaviors in 0- to 5-year-olds are lacking. High-quality studies are therefore required, to develop proxy-report questionnaires and evaluate their measurement properties.
CRD42020169268.
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