174 research outputs found

    Baryon Magnetic Moments and Axial Coupling Constants with Relativistic and Exchange Current Effects

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    The large relativistic corrections to the constituent quark current operators improve the predictions for the axial couplings of the baryons, but worsen those for their magnetic moments. The exchange current corrections that are associated with flavor and spin dependent hyperfine interactions between the quarks with a form suggested by pseudoscalar meson exchange can compensate the relativistic corrections to the baryon magnetic moments. This is demonstrated by a calculation of the magnetic moments of the non-strange and strange baryons using wave functions and exchange current operators, which correspond to a recent phenomenological spin- and flavor dependent interquark interaction model with a linear confining interaction, which yields a spectrum close to the empirical one. The possibility that part of the flavor and spin dependent interaction could be due to vector and axial-vector exchange is explored.Comment: Confinement exchange current contribution included, results improved, coauthor list expande

    The π−\pi-Gluon Exchange Interaction Between Constituent Quarks

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    The interaction mediated by irreducible pion and gluon exchange between constituent quarks is calculated and shown to have a strong tensor component, which tends to cancel the pion exchange tensor interaction between quarks. Its spin-spin component is somewhat weaker than the pion exchange spin-spin interaction, while its central and spin-orbit components are small in comparison to the corresponding single gluon exchange interactions. The combination of the π−\pi-gluon exchange interaction with the single pion exchange interaction and a weak gluon exchange interaction between constituent quarks has the qualitative features required for understanding the hyperfine splittings of the spectra of the nucleon and the Δ\Delta resonances.Comment: LaTeX, 17 pages, 5 Postscript figure

    Population‐based study of anastomotic stricture rates after minimally invasive and open oesophagectomy for cancer

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    Background The population‐based incidence of anastomotic stricture after minimally invasive oesophagectomy (MIO) and open oesophagectomy (OO) is not known. The aim of this study was to compare rates of anastomotic stricture requiring dilatation after the two approaches in an unselected cohort using nationwide data from Finland and Sweden. Methods All patients who had MIO or OO for oesophageal cancer between 2007 and 2014 were identified from nationwide registries in Finland and Sweden. Outcomes were the overall rate of anastomotic stricture and need for single or repeated (3 or more) dilatations for stricture within the first year after surgery. Multivariable Cox regression provided hazard ratios (HRs) with 95 per cent confidence intervals, adjusted for age, sex, co‐morbidity, histology, stage, year, country, hospital volume, length of hospital stay and readmissions. Results Some 239 patients underwent MIO and 1430 had an open procedure. The incidence of strictures requiring one dilatation was 16·7 per cent, and that for strictures requiring three or more dilatations was 6·6 per cent. The HR for strictures requiring one dilatation was not increased after MIO compared with that after OO (HR 1·19, 95 per cent c.i. 0·66 to 2·12), but was threefold higher for repeated dilatations (HR 3·25, 1·43 to 7·36). Of 18 strictures following MIO, 14 (78 per cent) occurred during the first 2 years after initiating this approach. Conclusion The need for endoscopic anastomotic dilatation after oesophagectomy was common, and the need for repeated dilatation was higher after MIO than following OO. The increased risk after MIO may reflect a learning curve. </div

    Meson exchange and nucleon polarizabilities in the quark model

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    Modifications to the nucleon electric polarizability induced by pion and sigma exchange in the q-q potentials are studied by means of sum rule techniques within a non-relativistic quark model. Contributions from meson exchange interactions are found to be small and in general reduce the quark core polarizability for a number of hybrid and one-boson-exchange q-q models. These results can be explained by the constraints that the baryonic spectrum impose on the short range behavior of the mesonic interactions.Comment: 11 pages, 1 figure added, expanded discussio

    Gene Polymorphism of Toll-Like Receptors and Lung Function at Five to Seven Years of Age after Infant Bronchiolitis

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    Toll-like receptors (TLR) play a crucial role in innate immunity, protecting the host from pathogens such as viruses. Genetic variations in TLRs have been associated with the severity of viral bronchiolitis in infancy and with the later occurrence of post-bronchiolitis asthma. The aim of the present study was to evaluate if there are any exploratory associations between TLR gene polymorphisms and lung function at 5 to 7 years of age in former bronchiolitis patients. METHODS: We performed impulse oscillometry (IOS) at the median age of 6.3 years for 103 children who had been hospitalized for bronchiolitis at less than six months of age. The main parameters evaluated were airway resistance and reactance at 5Hz in baseline and post-exercise measurements. Data on single nucleotide polymorphisms (SNP) of TLR1 rs5743618, TLR2 rs5743708, TLR6 rs5743810 and TLR10 rs4129009 (TLR2 subfamily) and TLR3 rs3775291, TLR4 rs4986790, TLR7 rs179008, TLR8 rs2407992 and TLR 9 rs187084 were available for analyses. RESULTS: The TLR4 rs4986790 wild genotype A/A was associated with a greater Rrs5 response (0.72 vs. -0.42, p = 0.03) to exercise. In TLR6 rs5743810, the minor allele T was associated with greater Rrs5 response (0.80 vs. -0.03, p = 0.04) to exercise. In TLR7 rs179008, the major allele A was associated with baseline decline in dRrs/df (-1.03 vs 0.61, p = 0.01) and increased Fres (2.28 vs. 0.89, p = 0.01) in girls. CONCLUSION: Among the nine studied TLRs, only TLR7 rs179008 showed some exploratory associations with post-bronchiolitis lung function deficiency, and polymorphisms of TLR4 rs4986790, and TLR6 rs5743810 in particular, with airway reactivity. These findings call for further confirmatory studies.Public Library of Science open acces

    Adaptation to climate change in Finland : Current state and future prospects

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    The KOKOSOPU project has aimed at a comprehensive evaluation of the national adaptation policy with particular emphasis on the National Adaptation Plan and international policy development. In addition, future challenges related to societal development have been taken into account. Projections of climate change, Finland’s Climate Act and the strengthened adaptation policy in the EU emphasise the importance of the national adaptation policy. A key objective of the National Adaptation Plan 2014–2022 was to strengthen the adaptive capacity of Finnish society. This objective is still relevant. The conditions for reaching the objective have, however, partly changed. First, cross border consequences of climate change are increasingly emphasised. Second, issues of justice and fairness with respect to the consequences of climate change and adaptation actions are being identified as central. Third, greater weight is given to the overall sustainability of adaptation and climate action. The changing conditions for climate change adaptation should be reflected in the allocation of resources, in improved coordination within the administration and in co-operation between the public and private sector. In addition, knowledge and education should be enhanced, and resources provided for RDI, and for monitoring and evaluation that supports continued improvement of adaptation activities

    Adaptation to climate change in Finland : Current state and future prospects

    Get PDF
    The KOKOSOPU project has aimed at a comprehensive evaluation of the national adaptation policy with particular emphasis on the National Adaptation Plan and international policy development. In addition, future challenges related to societal development have been taken into account. Projections of climate change, Finland’s Climate Act and the strengthened adaptation policy in the EU emphasise the importance of the national adaptation policy. A key objective of the National Adaptation Plan 2014–2022 was to strengthen the adaptive capacity of Finnish society. This objective is still relevant. The conditions for reaching the objective have, however, partly changed. First, cross border consequences of climate change are increasingly emphasised. Second, issues of justice and fairness with respect to the consequences of climate change and adaptation actions are being identified as central. Third, greater weight is given to the overall sustainability of adaptation and climate action. The changing conditions for climate change adaptation should be reflected in the allocation of resources, in improved coordination within the administration and in co-operation between the public and private sector. In addition, knowledge and education should be enhanced, and resources provided for RDI, and for monitoring and evaluation that supports continued improvement of adaptation activities

    Long-Term Survival After Transhiatal Versus Transthoracic Esophagectomy: A Population-Based Nationwide Study in Finland

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    Background No population-based studies comparing long-term survival after transhiatal esophagectomy (THE) and transthoracic esophagectomy (TTE) exist. This study aimed to compare the 5-year survival of esophageal cancer patients undergoing THE or TTE in a population-based nationwide setting. Methods This study included all curatively intended THE and TTE for esophageal cancer in Finland during 1987-2016, with follow-up evaluation until 31 December 2019. Cox proportional hazard models provided hazard ratios (HRs) with 95% confidence intervals (CIs) of 5-year and 90-day mortality. The results were adjusted for age, sex, year of operation, comorbidities, histology, neoadjuvant treatment, and pathologic stage. Results A total of 1338 patients underwent THE (n = 323) or TTE (n = 1015). The observed 5-year survival rate was 39.3% after THE and 45.0% after TTE (p = 0.072). In adjusted model 1, THE was not associated with greater 5-year mortality (HR 0.99; 95% CI 0.82-1.20) than TTE. In adjusted model 2, including T stage instead of pathologic stage, the 5-year mortality hazard rates after THE (HR 0.87, 95% CI 0.72-1.05) and TTE were comparable. The 90-day mortality rate for THE was higher than for TTE (adjusted HR 0.72; 95% CI 0.45-1.14). In subgroup analyses, no differences between THE and TTE were observed in Siewert II gastroesophageal junction cancers, esophageal cancers, or pN0 tumors, nor in the comparison of THE and TTE with two-field lymphadenectomy. The sensitivity analysis, including patients with missing patient records, who underwent surgery during 1996-2016 mirrored the main analysis. Conclusions This Finnish population-based nationwide study suggests no difference in 5-year or 90-day mortality after THE and TTE for esophageal cancer.</p

    Ecological commonalities among pelagic fishes: comparison of freshwater ciscoes and marine herring and sprat

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    Systematic comparisons of the ecology between functionally similar fish species from freshwater and marine aquatic systems are surprisingly rare. Here, we discuss commonalities and differences in evolutionary history, population genetics, reproduction and life history, ecological interactions, behavioural ecology and physiological ecology of temperate and Arctic freshwater coregonids (vendace and ciscoes, Coregonus spp.) and marine clupeids (herring, Clupea harengus, and sprat, Sprattus sprattus). We further elucidate potential effects of climate warming on these groups of fish based on the ecological features of coregonids and clupeids documented in the previous parts of the review. These freshwater and marine fishes share a surprisingly high number of similarities. Both groups are relatively short-lived, pelagic planktivorous fishes. The genetic differentiation of local populations is weak and seems to be in part correlated to an astonishing variability of spawning times. The discrete thermal window of each species influences habitat use, diel vertical migrations and supposedly also life history variations. Complex life cycles and preference for cool or cold water make all species vulnerable to the effects of global warming. It is suggested that future research on the functional interdependence between spawning time, life history characteristics, thermal windows and genetic differentiation may profit from a systematic comparison of the patterns found in either coregonids or clupeids
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