142 research outputs found

    Pine root condition and growth disturbances.

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    Heavy Higgs production and decay via e+eZ0H0bbˉZ0Z0e^+e^-\to Z^0 H^0 \to b\bar bZ^0Z^0 and irreducible backgrounds at Next Linear Colliders

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    The complete matrix element for e^+e^-\ar b\bar bZ^0Z^0 has been computed at tree--level and applied to Z0H0Z^0H^0--production followed by Z^0\ar b\bar b and H^0\ar Z^0Z^0, including all the irreducible background, at Next Linear Colliders. We find that, assuming flavour identification of the Z0Z^0--decay products, this channel, together with e^+e^-\ar b\bar bW^+W^- in which Z^0H^0\ar (b\bar b)(W^+W^-), can be important for the study of the parameters of the Standard Model Higgs boson over the heavy mass range 2M_{Z^0}\Ord M_{H^0}\Ord 2{m_t}.Comment: 24 pages, LaTeX (uses Feynman), 7 figures (.ps files or hardcopies of figs.2-7 available upon request

    Discourses of conflict and collaboration and institutional context in the implementation of forest conservation policies in Soria, Spain

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    This article examines the emergence of conflict and collaboration in the implementation of forest conservation policies in Soria, Spain. We draw insights from discursive institutionalism and use a comparative case study approach to analyse and compare a situation of social conflict over the Natural Park declaration in the Sierra de Urbión, and a civil society led collaborative process to develop management plans for the “Sierra de Cabrejas” in Soria. The implementation of the EU Habitats Directive generated different outcomes in these two cases, which unfolded in the context of the same nature conservation legislation and national and provincial administrative structures but differed in terms of types of forests involved, property rights arrangements and forest use histories. We critically examine the influence of the institutional context and dominant discourses on the emergence of outcomes: conflict emerged where local institutions and discourses were threatened by the EU directive, while collaboration was possible where local institutions and counter-discourses were weak. We find that the institutional context plays an important part in determining local discourses in the implementation of forest conservation policies. Yet local counter-discourses have limited influence in the implementation and policy processes in the face of contestation by the discourses of regional civil servants conservation activists

    Omphalocele in Finland from 1993 to 2014: Trends, Prevalence, Mortality, and Associated Malformations-A Population-Based Study

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    Introduction The aim of this study is to assess the changes in prevalence, mortality and termination pregnancy of omphalocele, and to identify associated anomalies.Materials and Methods A population-based nationwide register study. All cases with omphalocele were identified in the Finnish Register of Congenital Malformations and the Care Register for Health Care from 1993 to 2014 including live births, stillbirths, and terminations of pregnancy due to fetal anomalies. Associated anomalies were recorded and analyzed, and perinatal and infant mortality and prevalence were calculated.Results There were 600 cases with omphalocele including 229 live births, 39 stillbirths, and 332 (55%) abortions. Birth prevalence in Finland was 1.96 per 10,000 births with no consistent trend over time. However, total prevalence was much higher (4.71/10,000) because more than half of these families chose option for the termination of pregnancy. Omphalocele is often complicated with other anomalies; most commonly chromosomal abnormalities (9.3%), heart defects (6.3%), central nervous system anomalies (3.0%), gastrointestinal, and urogenital malformations (both 2.0%). Proportion of chromosomal and central nervous system abnormalities were even higher in terminated pregnancies. Overall infant mortality was 22%. Total 1-year survival rates for isolated omphalocele, cases with multiple anomalies and neonates with chromosomal defects were 80, 88, and 17%, respectively.Conclusion Omphalocele is a rare congenital anomaly, often associated with other malformations. Our data suggest that isolated cases may be more common than previously thought. In the absence of chromosomal defects, survival is reasonably good. Regardless, more than half of these pregnancies are often terminated.</p

    Extended spectrum penicillins reduce the risk of omphalocele: A population-based case-control study

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    Background: Omphalocele is a major congenital anomaly associated with significant morbidity and mortality. Regardless, the influence of maternal use of prescription drugs on the risk of omphalocele has only been addressed in a handful of studies. The aim of this study was to assess the influence of maternal risk factors and prescription drugs in early pregnancy on the risk of omphalocele.Methods: We performed a nationwide register-based case-control study in Finland. The analysis is based on the Finnish Register of Congenital Malformations and Drugs and Pregnancy databases, both upheld by the Finnish Institute for Health and Welfare. All omphalocele cases were identified between Jan 1, 2004, and Dec 31, 2014. Five age-matched controls from the same geographical region were randomly selected for each case. The main outcome measures were maternal risk factors for omphalocele. Our analysis compared the maternal characteristics and the use of prescription drugs during the first trimester of pregnancy between case and control mothers.Results: Mothers of 359 omphalocele cases were compared with 1738 randomly selected age and area-matched mothers of healthy infants between 1 January 2014 and 31 December 2014. Both maternal obesity (BMI ≥30) and diabetes increased the risk for omphalocele, and their co-occurrence accumulated this risk (aOR 5.06, 95% Cl 1.19-21.4). Similarly, history of multiple miscarriages was an independent risk factor (2.51, 1.16-5.43). The oral use of extended spectrum penicillins during the first trimester of pregnancy had a significant, protective influence (0.17, 0.04-0.71). These analyses were adjusted for sex, parity, and risk factors reported above. No significant changes in risk were observed with any other medication used during the first trimester.Conclusion: In conclusion, these findings may suggest that extended spectrum penicillins in the first trimester reduces the risk of omphalocle formation. Additionally, consistent with earlier studies, previous repeated miscarriages, maternal obesity, and diabetes were significant risk factors for omphalocele.</p

    Composite Higgs Search at the LHC

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    The Higgs boson production cross-sections and decay rates depend, within the Standard Model (SM), on a single unknown parameter, the Higgs mass. In composite Higgs models where the Higgs boson emerges as a pseudo-Goldstone boson from a strongly-interacting sector, additional parameters control the Higgs properties which then deviate from the SM ones. These deviations modify the LEP and Tevatron exclusion bounds and significantly affect the searches for the Higgs boson at the LHC. In some cases, all the Higgs couplings are reduced, which results in deterioration of the Higgs searches but the deviations of the Higgs couplings can also allow for an enhancement of the gluon-fusion production channel, leading to higher statistical significances. The search in the H to gamma gamma channel can also be substantially improved due to an enhancement of the branching fraction for the decay of the Higgs boson into a pair of photons.Comment: 32 pages, 16 figure

    Predictions for Higgs production at the Tevatron and the associated uncertainties

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    We update the theoretical predictions for the production cross sections of the Standard Model Higgs boson at the Fermilab Tevatron collider, focusing on the two main search channels, the gluon-gluon fusion mechanism ggHgg \to H and the Higgs-strahlung processes qqˉVHq \bar q \to VH with V=W/ZV=W/Z, including all relevant higher order QCD and electroweak corrections in perturbation theory. We then estimate the various uncertainties affecting these predictions: the scale uncertainties which are viewed as a measure of the unknown higher order effects, the uncertainties from the parton distribution functions and the related errors on the strong coupling constant, as well as the uncertainties due to the use of an effective theory approach in the determination of the radiative corrections in the ggHgg \to H process at next-to-next-to-leading order. We find that while the cross sections are well under control in the Higgs--strahlung processes, the theoretical uncertainties are rather large in the case of the gluon-gluon fusion channel, possibly shifting the central values of the next-to-next-to-leading order cross sections by more than 40\approx 40%. These uncertainties are thus significantly larger than the 10\approx 10% error assumed by the CDF and D0 experiments in their recent analysis that has excluded the Higgs mass range MH=M_H=162-166 GeV at the 95% confidence level. These exclusion limits should be, therefore, reconsidered in the light of these large theoretical uncertainties.Comment: 40 pages, 12 figures. A few typos are corrected and some updated numbers are provide

    Intermediate mass standard model Higgs boson at the proposed CERN LEP\otimesLHC epep collider

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    The production of the \sm\ Higgs ϕ\phi with intermediate mass at the proposed CERN LEP\otimesLHC epep collider in γq(qˉ)W±ϕq(qˉ)\gamma q(\bar q)\rightarrow W^\pm\phi q'(\bar q'), γq(qˉ)Z0ϕq(qˉ)\gamma q(\bar q)\rightarrow Z^0\phi q(\bar q) and gγqqˉϕg\gamma\rightarrow q\bar q\phi events is studied. This is done for all possible (massive) flavours of the quarks q(q)q(q') and using photons generated via Compton back--scattering of laser light. We study signatures in which the Higgs decays to bbˉb\bar b--pairs and the electroweak vector bosons W±W^\pm and Z0Z^0 decay either hadronically or leptonically. All possible backgrounds to these signals are also computed. Flavour identification on bb--jets is assumed. Explicit formulae for the helicity amplitudes of the above processes are given.Comment: 31 pages, Latex, 8 figures uuencoded, revised version, significant changes in the discussion of the results, in tables and figure
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