509 research outputs found

    What I Have Learned from 4 Years of Alfalfa Grazing Tolerance Variety Trials

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    There has been interest in alfalfa varieties that would tolerate grazing for some time. The spreading type alfalfas (such as Rambler, Spredor 2, Travois) have long been generally promoted as being tolerant of grazing. Over the years, most selection for tolerance to grazing was done using frequent clipping to simulate grazing. Studies conducted at the University of Georgia in the 1980\u27s found that alfalfa varieties performed differently when grazed frequently compared to clipping frequently. This line of research eventually led to the release of \u27AlfaGraze\u27 alfalfa which was the first variety ever to be selected primarily by overgrazing by livestock. The advent of this variety and others soon after raised the need for verification of grazing tolerance under Kentucky conditions

    The Cozzo Disi mine (Casteltermini, Sicily, Italy) a multi-disciplinary approach to record, study, preserve and develop the mining heritage in Sicily

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    Cozzo Disi was one of the main sulphur mines in Italy, but after the closure and more than 10 years of desertion, urgent works are now necessary to save it from vandalism and flooding. This big mine contains geological and mineralogical peculiarities, so uncommon to be sometimes unique: this is the case of the \u201cGrandi Garbere\u201d at 3rd level, majestic karst cavities, containing magnificent selenite crystals documented by old miners. The possibility to have a \u201cSicilian Naica\u201d attracted a multi-disciplinary underground task-force, now exploring the mine underground, in order to inspect old works and their good-safety conditions, and to achieve the rooms/caves of \u201cGrandi Garbere\u201d. This extraordinary discovery should be relevant for the future of this territory. In the past, the mine was characterized by huge safety problems: hydrogen sulfide, carbon dioxide and explosive atmospheres; so, the team involved in actual and future explorations has to move with caution, using adequate equipment and - if necessary - waiting for acceptable environmental conditions created by artificial tools (ventilation, pumping, etc.)

    Atorvastatin combined to interferon to verify the efficacy (ACTIVE) in relapsing-remitting active multiple sclerosis patients: a longitudinal controlled trial of combination therapy.

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    A large body of evidence suggests that, besides their cholesterol-lowering effect, statins exert anti-inflammatory action. Consequently, statins may have therapeutic potential in immune-mediated disorders such as multiple sclerosis. Our objectives were to determine safety, tolerability and efficacy of low-dose atorvastatin plus high-dose interferon beta-1a in multiple sclerosis patients responding poorly to interferon beta-1a alone. Relapsing–remitting multiple sclerosis patients, aged 18–50 years, with contrast-enhanced lesions or relapses while on therapy with interferon beta-1a 44 mg (three times weekly) for 12 months, were randomized to combination therapy (interferon+atorvastatin 20mg per day; group A) or interferon alone (group B) for 24 months. Patients underwent blood analysis and clinical assessment with the Expanded Disability Status Scale every 3 months, and brain gadolinium-enhanced magnetic resonance imaging at screening, and 12 and 24 months thereafter. Primary outcome measure was contrast-enhanced lesion number. Secondary outcome measures were number of relapses, EDSS variation and safety laboratory data. Forty-five patients were randomized to group A (n 1⁄4 21) or B (n 1⁄4 24). At 24 months, group A had significantly fewer contrast-enhanced lesions versus baseline (p 1⁄4 0.007) and significantly fewer relapses versus the two pre-randomization years (p < 0.001). At survival analysis, the risk for a 1-point EDSS increase was slightly higher in group B than in group A (p 1⁄4 0.053). Low-dose atorvastatin may be beneficial, as add-on therapy, in poor responders to high-dose interferon beta-1a alone

    8Li+alpha decay of 12B and its possible astrophysical implications

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    The 12B excitation energy spectrum has been obtained from coincidence measurements of the 9Be+7Li -> 2alpha+8Li reaction at E{0}=52 MeV. The decay of the states at excitations between 10 and 16 Mev into alpha$+8Li has been observed for the first time. Observed alpha-decay indicates possible cluster structure of the 12B excited states. The influence of these states on the cross section of the astrophysically important 8Li(alpha,n)11B and 9Be+t reactions is discussed and the results are compared with existing results.Comment: accepted for publication in Europhysics Letter

    Evaluating Varieties of Alfalfa and Tall Fescue for Tolerance to Over-Grazing by Cattle

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    Cultivars of alfalfa (Medicago sativa L.) and tall fescue (Festuca arundinacea Schreb.) were seeded in small (1.5 m x 4.6 m) plots and harvested for estimating yield the following spring. Plots were then grazed by cattle continuously for the remainder of the season so as to keep stand heights at 7.5 cm or less. This procedure was repeated for one or two more grazing seasons, depending on stand survival. Stands were visually rated for stand in the fall and spring. Marked differences in grazing tolerance were observed among alfalfa cultivars, following closely the commercial designations as grazing-type or hay-type alfalfa. Some cultivars of endophyte-free tall fescue were as grazing tolerant as endophyte-infected Kentucky 31 tall fescue

    Trojan Horse as an indirect technique in nuclear astrophysics. Resonance reactions

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    The Trojan Horse method is a powerful indirect technique that provides information to determine astrophysical factors for binary rearrangement processes x+A→b+Bx + A \to b + B at astrophysically relevant energies by measuring the cross section for the Trojan Horse reaction a+A→y+b+Ba + A \to y+ b + B in quasi-free kinematics. We present the theory of the Trojan Horse method for resonant binary subreactions based on the half-off-energy-shell R matrix approach which takes into account the off-energy-shell effects and initial and final state interactions.Comment: 6 pages and 1 figur

    Determination of the photodisintegration reaction rates involving charged particles: systematical calculations and proposed measurements based on Extreme Light Infrastructure - Nuclear Physics (ELI-NP)

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    Photodisintegration reaction rates involving charged particles are of relevance to the p-process nucleosynthesis that aims at explaining the production of the stable neutron-deficient nuclides heavier than iron. In this study, the cross sections and astrophysical rates of (g,p) and (g,a) reactions for about 3000 target nuclei with 10<Z<100 ranging from stable to proton dripline nuclei are computed. To study the sensitivity of the calculations to the optical model potentials (OMPs), both the phenomenological Woods-Saxon and the microscopic folding OMPs are taken into account. The systematic comparisons show that the reaction rates, especially for the (g,a) reaction, are dramatically influenced by the OMPs. Thus the better determination of the OMP is crucial to reduce the uncertainties of the photodisintegration reaction rates involving charged particles. Meanwhile, a gamma-beam facility at ELI-NP is being developed, which will open new opportunities to experimentally study the photodisintegration reactions of astrophysics interest. Considering both the important reactions identified by the nucleosynthesis studies and the purpose of complementing the experimental results for the reactions involving p-nuclei, the measurements of six (g,p) and eight (g,a) reactions based on the gamma-beam facility at ELI-NP and the ELISSA detector for the charged particles detection are proposed, and the GEANT4 simulations are correspondingly performed. The minimum required energies of the gamma-beam to measure these reactions are estimated. It is shown that the direct measurements of these photonuclear reactions within the Gamow windows at T_9=2.5 for p-process are fairly feasible and promising at ELI-NP. The expected experimental results will be used to constrain the OMPs of the charged particles, which can eventually reduce the uncertainties of the reaction rates for the p-process nucleosynthesis.Comment: 14 pages, 8 figures, Phys. Rev. C accepte

    Prompt electrons driving ion acceleration and formation of a two temperatures plasma in nanosecond laser-ablation domain

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    We present the results of an experiment on plasma generation via laser ablation at 10^12 W/cm^2 of power intensity and in a nanosecond domain. Prompt electrons emission and complex plasma plume fragmentation were simultaneously observed for the first time in this laser intensity regime, along with a double electron temperature inside the plasma bulk surviving for a long time to the plume expansion. 1D PIC simulations are in agreement with experimental data as long as the emission of initial prompt electrons is considered. This assumption results to be the key to explain all the other experimental evidences.Comment: 5 pages, 6 figures, Europhysics Letters in pres

    Migraine and Cranial Autonomic Symptoms in Children and Adolescents: A Clinical Study

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    The frequency of cranial autonomic symptoms in children affected by primary headaches is uncertain. The aim of our study was to estimate the frequency of symptoms in pediatric headaches and correlate it with main migraine characteristics. A questionnaire investigating the presence of cranial autonomic symptoms was administered to all children with primary headache for 2 years. A total of 230 children with primary headache (105 males, 125 females) were included. Two hundred two children were affected by migraine and 28 (12.2%) by other primary headaches. Cranial autonomic symptoms were significantly complained by migraineurs (55% vs 17.8%) (P &lt; .001) and by children with higher frequency of migraine attacks (odds ratio = 2.6, confidence interval = 1.4-4.7, P = .001). Our findings show that cranial autonomic symptoms are rather common during pediatric migraine attacks. The association between cranial autonomic symptoms and higher frequency of attacks might suggest the role of the trigeminal-autonomic reflex in migraine pathophysiolog
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