191 research outputs found

    Gluon confinement criterion in QCD

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    We fix exactly and uniquely the infrared structure of the full gluon propagator in QCD, not solving explicitly the corresponding dynamical equation of motion. By construction, this structure is an infinite sum over all possible severe (i.e., more singular than 1/q21/q^2) infrared singularities. It reflects the zero momentum modes enhancement effect in the true QCD vacuum, which is due to the self-interaction of massless gluons. It existence automatically exhibits a characteristic mass (the so-called mass gap). It is responsible for the scale of nonperturbative dynamics in the true QCD ground state. The theory of distributions, complemented by the dimensional regularization method, allows one to put the severe infrared singularities under the firm mathematical control. By an infrared renormalization of a mass gap only, the infrared structure of the full gluon propagator is exactly reduced to the simplest severe infrared singularity, the famous (q2)−2(q^2)^{-2}. Thus we have exactly established the interaction between quarks (concerning its pure gluon (i.e., nonlinear) contribution) up to its unimportant perturbative part. This also makes it possible for the first time to formulate the gluon confinement criterion and intrinsically nonperturbative phase in QCD in a manifestly gauge-invariant ways.Comment: 10 pages, no figures, no tables. Typos corrected and the clarification is intoduced. Shorten version to appear in Phys. Lett.

    Finland’s Dependence on Russian Energy-Mutually Beneficial Trade Relations or an Energy Security Threat?

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    Studies on energy security in the context of relations between European Union (EU) and Russia tend to focus on cases, with an open conflict related to supply, such as “hard” energy weapons, or on only one fuel, often natural gas. However, there is a need to understand the long-term impacts that energy relations have politically, economically and physically, and their linkages between resilience, sustainability and security. We analyse the Finnish-Russian energy relations as a case study, as they are characterised by a non-conflictual relationship. To assess this complex relationship, we apply the interdependence framework to analyse both the energy systems and energy strategies of Finland and Russia, and the energy security issues related to the notable import dependence on one supplier. Moreover, we analyse the plausible development of the energy trade between the countries in three different energy policy scenarios until 2040. The findings of the article shed light on how the trends in energy markets, climate change mitigation and broader societal and political trends could influence Russia’s energy trade relations with countries, such as Finland. Our analysis shows that Finland’s dependence on primary energy imports does not pose an acute energy security threat in terms of sheer supply, and the dependence is unlikely to worsen in the future. However, due to the difficulty in anticipating societal, political, and economic trends, there are possible developments that could affect Finland.Peer reviewe

    Arctic air pollution: Challenges and opportunities for the next decade

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    The Arctic is a sentinel of global change. This region is influenced by multiple physical and socio-economic drivers and feedbacks, impacting both the natural and human environment. Air pollution is one such driver that impacts Arctic climate change, ecosystems and health but significant uncertainties still surround quantification of these effects. Arctic air pollution includes harmful trace gases (e.g. tropospheric ozone) and particles (e.g. black carbon, sulphate) and toxic substances (e.g. polycyclic aromatic hydrocarbons) that can be transported to the Arctic from emission sources located far outside the region, or emitted within the Arctic from activities including shipping, power production, and other industrial activities. This paper qualitatively summarizes the complex science issues motivating the creation of a new international initiative, PACES (air Pollution in the Arctic: Climate, Environment and Societies). Approaches for coordinated, international and interdisciplinary research on this topic are described with the goal to improve predictive capability via new understanding about sources, processes, feedbacks and impacts of Arctic air pollution. Overarching research actions are outlined, in which we describe our recommendations for 1) the development of trans-disciplinary approaches combining social and economic research with investigation of the chemical and physical aspects of Arctic air pollution; 2) increasing the quality and quantity of observations in the Arctic using long-term monitoring and intensive field studies, both at the surface and throughout the troposphere; and 3) developing improved predictive capability across a range of spatial and temporal scales

    Metabolomic Profiling of Statin Use and Genetic Inhibition of HMG-CoA Reductase

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    Background Statins are first-line therapy for cardiovascular disease prevention, but their systemic effects across lipoprotein subclasses, fatty acids, and circulating metabolites remain incompletely characterized. Objectives This study sought to determine the molecular effects of statin therapy on multiple metabolic pathways. Methods Metabolic profiles based on serum nuclear magnetic resonance metabolomics were quantified at 2 time points in 4 population-based cohorts from the United Kingdom and Finland (N = 5,590; 2.5 to 23.0 years of follow-up). Concentration changes in 80 lipid and metabolite measures during follow-up were compared between 716 individuals who started statin therapy and 4,874 persistent nonusers. To further understand the pharmacological effects of statins, we used Mendelian randomization to assess associations of a genetic variant known to mimic inhibition of HMG-CoA reductase (the intended drug target) with the same lipids and metabolites for 27,914 individuals from 8 population-based cohorts. Results Starting statin therapy was associated with numerous lipoprotein and fatty acid changes, including substantial lowering of remnant cholesterol (80% relative to low-density lipoprotein cholesterol [LDL-C]), but only modest lowering of triglycerides (25% relative to LDL-C). Among fatty acids, omega-6 levels decreased the most (68% relative to LDL-C); other fatty acids were only modestly affected. No robust changes were observed for circulating amino acids, ketones, or glycolysis-related metabolites. The intricate metabolic changes associated with statin use closely matched the association pattern with rs12916 in the HMGCR gene (R2 = 0.94, slope 1.00 ± 0.03). Conclusions Statin use leads to extensive lipid changes beyond LDL-C and appears efficacious for lowering remnant cholesterol. Metabolomic profiling, however, suggested minimal effects on amino acids. The results exemplify how detailed metabolic characterization of genetic proxies for drug targets can inform indications, pleiotropic effects, and pharmacological mechanisms

    Pariisin kokouksen jÀlkeiset nÀkymÀt ja suomalaiset ilmastoratkaisut

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    Pariisin sopimus on oikeudellisesti sitova, globaalisti kattava ja se asettaa kunnianhimoisen tavoitteen hillitÀ ilmaston lÀmpenemistÀ 1,5-2 °C tasolle esiteolliseen aikaan verrattuna. Maailman ilmastotyön kunnianhimoa on parannettava jo ennen vuotta 2020, jotta nÀmÀ tavoitteet voidaan saavuttaa. Tapoja parantaa kunnianhimoa on monia. PÀÀstösitoumuksia voivat asettaa maat, joilta ne vielÀ puuttuvat. Muut maat voivat laajentaa tai kiristÀÀ sitoumuksiaan. PÀÀstöjÀ voidaan vÀhentÀÀ sitoumusten ulkopuolisilla aloilla. LisÀksi voidaan edistÀÀ kansainvÀlisiÀ yhteishankkeita ja ripeyttÀÀ ilmastoratkaisujen kÀyttöönottoa. YK:n ilmastosopimuksen liepeillÀ olevia kÀytÀnnön ilmastoratkaisuja edistÀviÀ, yhteistyötÀ kannustavia ja lisÀtoimista keskustelevia foorumeja on mahdollista vahvistaa. Suomi voi olla aktiivinen nÀissÀ kaikissa toimissa. Suomi voi myös moninkertaistaa myönteisen ilmastovaikutuksensa tarjoamalla muun maailman kÀyttöön pÀÀstöjÀ vÀhentÀviÀ ratkaisuja. NÀistÀ ratkaisuista esitellÀÀn sata ratkaisua kattaen laajan kirjon suomalaista osaamista energiantuotannosta maatalouteen, teknologiasta poliittiseen ohjaukseen ja yritysten tuotteista kansalaisjÀrjestöjen hankkeisiin. Pariisin sopimus on yleisesti otettu positiivisesti niin suurimmissa pÀÀstÀjÀmaissa, ilmastoneuvotteluja seuraavissa kansainvÀlisissÀ jÀrjestöissÀ kuin mediassa. 12 suurinta pÀÀstÀjÀÀ ovat hyvin tyytyvÀisiÀ sopimuksen tasapuolisuuteen ja vain hieman varauksellisia sopimuksen uskottavuuden suhteen. JÀrjestöissÀ ja median reaktioissa suhtautuminen on kuitenkin hajaantuneempaa. Raportissa tarkasteltujen 12 pÀÀstöiltÀÀn suurimman neuvotteluosapuolen INDC-tavoitteiden kunnianhimon taso, pÀÀstökehitys, pÀÀstöarvioiden laatu ja politiikkatoimet eroavat toisistaan hyvin paljon. Ilmastopolitiikan kunnianhimon tason vertailua kuitenkin hankaloittavat mm. joiden maiden pÀÀstöarvioiden huono luotettavuus sekÀ ns. yhteisten mutta erilaisten vastuiden periaate. NÀihin haasteisiin vastaaminen on yksi merkittÀviÀ kehitystehtÀviÀ Pariisin sopimuksen jatkotyössÀ

    Metabolic profiling of alcohol consumption in 9778 young adults

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    Background: High alcohol consumption is a major cause of morbidity, yet alcohol is associated with both favourable and adverse effects on cardiometabolic risk markers. We aimed to characterize the associations of usual alcohol consumption with a comprehensive systemic metabolite profile in young adults. Methods: Cross-sectional associations of alcohol intake with 86 metabolic measures were assessed for 9778 individuals from three population-based cohorts from Finland (age 24-45 years, 52% women). Metabolic changes associated with change in alcohol intake during 6-year follow-up were further examined for 1466 individuals. Alcohol intake was assessed by questionnaires. Circulating lipids, fatty acids and metabolites were quantified by high-throughput nuclear magnetic resonance metabolomics and biochemical assays. Results: Increased alcohol intake was associated with cardiometabolic risk markers across multiple metabolic pathways, including higher lipid concentrations in HDL subclasses and smaller LDL particle size, increased proportions of monounsaturated fatty acids and decreased proportion of omega-6 fatty acids, lower concentrations of glutamine and citrate (P<0.001 for 56 metabolic measures). Many metabolic biomarkers displayed U-shaped associations with alcohol consumption. Results were coherent for men and women, consistent across the three cohorts and similar if adjusting for body mass index, smoking and physical activity. The metabolic changes accompanying change in alcohol intake during follow-up resembled the cross-sectional association pattern (R-2 = 0.83, slope = 0.7260.04). Conclusions: Alcohol consumption is associated with a complex metabolic signature, including aberrations in multiple biomarkers for elevated cardiometabolic risk. The metabolic signature tracks with long-term changes in alcohol consumption. These results elucidate the double-edged effects of alcohol on cardiovascular risk.Peer reviewe

    Anchoring of proteins to lactic acid bacteria

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    The anchoring of proteins to the cell surface of lactic acid bacteria (LAB) using genetic techniques is an exciting and emerging research area that holds great promise for a wide variety of biotechnological applications. This paper reviews five different types of anchoring domains that have been explored for their efficiency in attaching hybrid proteins to the cell membrane or cell wall of LAB. The most exploited anchoring regions are those with the LPXTG box that bind the proteins in a covalent way to the cell wall. In recent years, two new modes of cell wall protein anchoring have been studied and these may provide new approaches in surface display. The important progress that is being made with cell surface display of chimaeric proteins in the areas of vaccine development and enzyme- or whole-cell immobilisation is highlighted.

    Effects of hormonal contraception on systemic metabolism : cross-sectional and longitudinal evidence

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    Background: Hormonal contraception is commonly used worldwide, but its systemic effects across lipoprotein subclasses, fatty acids, circulating metabolites and cytokines remain poorly understood. Methods: A comprehensive molecular profile (75 metabolic measures and 37 cytokines) was measured for up to 5841 women (age range 24-49 years) from three population-based cohorts. Women using combined oral contraceptive pills (COCPs) or progestin-only contraceptives (POCs) were compared with those who did not use hormonal contraception. Metabolomics profiles were reassessed for 869 women after 6 years to uncover the metabolic effects of starting, stopping and persistently using hormonal contraception. Results: The comprehensive molecular profiling allowed multiple new findings on the metabolic associations with the use of COCPs. They were positively associated with lipoprotein subclasses, including all high-density lipoprotein (HDL) subclasses. The associations with fatty acids and amino acids were strong and variable in direction. COCP use was negatively associated with albumin and positively associated with creatinine and inflammatory markers, including glycoprotein acetyls and several growth factors and interleukins. Our findings also confirmed previous results e.g. for increased circulating triglycerides and HDL cholesterol. Starting COCPs caused similar metabolic changes to those observed cross-sectionally: the changes were maintained in consistent users and normalized in those who stopped using. In contrast, POCs were only weakly associated with metabolic and inflammatory markers. Results were consistent across all cohorts and for different COCP preparations and different types of POC delivery. Conclusions: Use of COCPs causes widespread metabolic and inflammatory effects. However, persistent use does not appear to accumulate the effects over time and the metabolic perturbations are reversed upon discontinuation. POCs have little effect on systemic metabolism and inflammation.Peer reviewe
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