430 research outputs found

    The Massive Schwinger Model in a Fast Moving Frame

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    We present a non-perturbative study of the massive Schwinger model. We use a Hamiltonian approach, based on a momentum lattice corresponding to a fast moving reference frame, and equal time quantization.Comment: contribution to Lattice'98 including: 2 style files (espcrc2.sty,psfig.sty) + text file (LaTeX) + 3 figures (ps) + complete paper(ps

    Coronary atherosclerosis screening in asymptomatic adults using coronary artery calcium for cardiovascular prevention: a systematic review of randomised controlled trials and prospective cohorts.

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    To review the available evidence of screening for atherosclerosis in adults in a primary prevention setting with coronary artery calcium scoring (CACS) on the impact on cardiovascular (CV) risk factor control, health behaviour and clinical events. Systematic review, reported in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE, Embase and Cochrane Central Register of Controlled Trials through 22 January 2025. We included randomised controlled trials (RCTs) and prospective cohorts, without language restrictions, comparing adults without cardiovascular diseases undergoing CACS to a control group that either did not undergo CACS or where the participants and physicians were blinded to its result. Outcomes included changes in CV risk factor control, CV therapy, changes in health behaviour at follow-up and clinical events (all-cause and CV mortality and non-fatal CV events). Two independent reviewers extracted data and assessed the risk of bias. Due to substantial heterogeneity among the included studies, a quantitative analysis was not possible. We identified seven RCTs and one observational study, with participants ranging from 56 to 43 447 with a total of 51 554. Populations were heterogeneous with a mean age range of 42-64 years, % women ranging from 21% to 100% and mean baseline CACS from 1.37 to >100 Agatston units. Interventions following CACS were also heterogeneous, ranging from simply communicating results to participants to initiating statin therapy for detectable CACS. One RCT demonstrated improvement regarding blood pressure (BP) (n=2137; change in systolic BP: CACS: -5 mm Hg; control: -7 mm Hg; p=0.02), several an improvement in blood lipids between groups (five studies, n=3693; eg, low-density lipoprotein (LDL) cholesterol: range -6.0 to -4.9 mg/dL). Results regarding CV medication (seven studies, n=51 104) were more discrepant, with some studies showing a decrease and others an increase in indication for or usage of CV medication. Three trials (n=3338) investigated adherence to CV medication, with only one showing increased adherence to statins (CACS: 63.3%; control: 45.6%; p=0.03). Five trials (n=3692) investigated behavioural changes, with one showing an increased motivation to change lifestyle (CACS: 94%; control: 62.8%; p=0.002) and another a higher adherence in self-reported physical activity (CACS: 96%; control: 59%; p<0.01). Due to low event rates, short follow-up and/or limited sample size, none (three studies, n=6552) demonstrated an effect on clinical CV events or all-cause mortality. Heterogeneity in interventions following CACS, population and studied outcomes did not permit pooling of results. Key limitations of this review reflect the limited availability of evidence and include the omission of potential harms of CACS screening, study heterogeneity, insufficient data on clinical events, a lack of economic assessments and the moderate to high risk of bias in most studies. CACS screening with a CACS-guided intervention might have a favourable effect on CV risk factor control and potentially on adherence to CV medication and increased motivation to change lifestyle in populations at intermediate to high risk. The available evidence is insufficient to determine whether screening asymptomatic patients with CACS has an impact on all-cause mortality or CV events. Despite its known strengths in predicting outcomes in individual patients, more evidence regarding the impact on clinical outcomes is needed to determine the clinical use of CACS for screening purposes in asymptomatic patients. CRD42022377727

    The evolutionary dynamics of microRNAs in domestic mammals

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    MiRNAs are crucial regulators of gene expression found across both the plant and animal kingdoms. While the number of annotated miRNAs deposited in miRBase has greatly increased in recent years, few studies provided comparative analyses across sets of related species, or investigated the role of miRNAs in the evolution of gene regulation. We generated small RNA libraries across 5 mammalian species (cow, dog, horse, pig and rabbit) from 4 different tissues (brain, heart, kidney and testis). We identified 1676 miRBase and 413 novel miRNAs by manually curating the set of computational predictions obtained from miRCat and miRDeep2. Our dataset spanning five species has enabled us to investigate the molecular mechanisms and selective pressures driving the evolution of miRNAs in mammals. We highlight the important contributions of intronic sequences (366 orthogroups), duplication events (135 orthogroups) and repetitive elements (37 orthogroups) in the emergence of new miRNA loci. We use this framework to estimate the patterns of gains and losses across the phylogeny, and observe high levels of miRNA turnover. Additionally, the identification of lineage-specific losses enables the characterisation of the selective constraints acting on the associated target sites. Compared to the miRBase subset, novel miRNAs tend to be more tissue specific. 20 percent of novel orthogroups are restricted to the brain, and their target repertoires appear to be enriched for neuron activity and differentiation processes. These findings may reflect an important role for young miRNAs in the evolution of brain expression plasticity. Many seed sequences appear to be specific to either the cow or the dog. Analyses on the associated targets highlight the presence of several genes under artificial positive selection, suggesting an involvement of these miRNAs in the domestication process. Altogether, we provide an overview on the evolutionary mechanisms responsible for miRNA turnover in 5 domestic species, and their possible contribution to the evolution of gene regulation

    Statistical Modeling of Single Target Cell Encapsulation

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    High throughput drop-on-demand systems for separation and encapsulation of individual target cells from heterogeneous mixtures of multiple cell types is an emerging method in biotechnology that has broad applications in tissue engineering and regenerative medicine, genomics, and cryobiology. However, cell encapsulation in droplets is a random process that is hard to control. Statistical models can provide an understanding of the underlying processes and estimation of the relevant parameters, and enable reliable and repeatable control over the encapsulation of cells in droplets during the isolation process with high confidence level. We have modeled and experimentally verified a microdroplet-based cell encapsulation process for various combinations of cell loading and target cell concentrations. Here, we explain theoretically and validate experimentally a model to isolate and pattern single target cells from heterogeneous mixtures without using complex peripheral systems.Wallace H. Coulter Foundation (Young Investigator in Bioengineering Award)National Institutes of Health (U.S.) (Grant R01AI081534)National Institutes of Health (U.S.) (Grant R21AI087107

    Th2 Cell-Intrinsic Hypo-Responsiveness Determines Susceptibility to Helminth Infection

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    The suppression of protective Type 2 immunity is a principal factor driving the chronicity of helminth infections, and has been attributed to a range of Th2 cell-extrinsic immune-regulators. However, the intrinsic fate of parasite-specific Th2 cells within a chronic immune down-regulatory environment, and the resultant impact such fate changes may have on host resistance is unknown. We used IL-4gfp reporter mice to demonstrate that during chronic helminth infection with the filarial nematode Litomosoides sigmodontis, CD4(+) Th2 cells are conditioned towards an intrinsically hypo-responsive phenotype, characterised by a loss of functional ability to proliferate and produce the cytokines IL-4, IL-5 and IL-2. Th2 cell hypo-responsiveness was a key element determining susceptibility to L. sigmodontis infection, and could be reversed in vivo by blockade of PD-1 resulting in long-term recovery of Th2 cell functional quality and enhanced resistance. Contrasting with T cell dysfunction in Type 1 settings, the control of Th2 cell hypo-responsiveness by PD-1 was mediated through PD-L2, and not PD-L1. Thus, intrinsic changes in Th2 cell quality leading to a functionally hypo-responsive phenotype play a key role in determining susceptibility to filarial infection, and the therapeutic manipulation of Th2 cell-intrinsic quality provides a potential avenue for promoting resistance to helminths

    Networking Our Way to Better Ecosystem Service Provision.

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    The ecosystem services (EcoS) concept is being used increasingly to attach values to natural systems and the multiple benefits they provide to human societies. Ecosystem processes or functions only become EcoS if they are shown to have social and/or economic value. This should assure an explicit connection between the natural and social sciences, but EcoS approaches have been criticized for retaining little natural science. Preserving the natural, ecological science context within EcoS research is challenging because the multiple disciplines involved have very different traditions and vocabularies (common-language challenge) and span many organizational levels and temporal and spatial scales (scale challenge) that define the relevant interacting entities (interaction challenge). We propose a network-based approach to transcend these discipline challenges and place the natural science context at the heart of EcoS research.The QUINTESSENCE Consortium gratefully acknowledges the support of Départment SPE and Métaprogramme ECOSERV of INRA, and the French ANR projects PEERLESS (ANR-12-AGRO-0006) and AgroBioSE (ANR-13-AGRO-0001).This is the final version of the article. It first appeared from Elsevier via http://dx.doi.org/10.1016/j.tree.2015.12.00

    Decomposers and root feeders interactively affect plant defence in Sinapis alba

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    Aboveground herbivory is well known to change plant growth and defence. In contrast, effects of soil organisms, acting alone or in concert, on allocation patterns are less well understood. We investigated separate and combined effects of the endogeic earthworm species Aporrectodea caliginosa and the root feeding nematode species Pratylenchus penetrans and Meloidogyne incognita on plant responses including growth and defence metabolite concentrations in leaves of white mustard, Sinapis alba. Soil biota had a strong impact on plant traits, with the intensity varying due to species combinations. Nematode infestation reduced shoot biomass and nitrogen concentration but only in the absence of earthworms. Earthworms likely counteracted the negative effects of nematodes. Infestation with the migratory lesion-nematode P. penetrans combined with earthworms led to increased root length. Earthworm biomass increased in the presence of this species, indicating that these nematodes increased the food resources of earthworms—presumably dead and decaying roots. Nitrogen-based defence compounds, i.e. glucosinolates, did not correlate with nitrogen levels. In the presence of earthworms, concentrations of aromatic glucosinolates in leaves were significantly increased. In contrast, infection with P. penetrans strongly decreased concentrations of glucosinolates (up to 81%). Infestation with the sedentary nematode M. incognita induced aromatic glucosinolates by more than 50% but only when earthworms were also present. Myrosinase activities, glucosinolate-hydrolysing enzymes, were unaffected by nematodes but reduced in the presence of earthworms. Our results document that root-feeding nematodes elicit systemic plant responses in defence metabolites, with the responses varying drastically with nematode species of different functional groups. Furthermore, systemic plant responses are also altered by decomposer animals, such as earthworms, challenging the assumption that induction of plant responses including defence traits is restricted to herbivores. Soil animals even interact and modulate the individual effects on plant growth and plant defence, thereby likely also influencing shoot herbivore attack
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