3,123 research outputs found
Prospects for the Search for a Standard Model Higgs Boson in ATLAS using Vector Boson Fusion
The potential for the discovery of a Standard Model Higgs boson in the mass
range m_H < 2 m_Z in the vector boson fusion mode has been studied for the
ATLAS experiment at the LHC. The characteristic signatures of additional jets
in the forward regions of the detector and of low jet activity in the central
region allow for an efficient background rejection. Analyses for the H -> WW
and H -> tau tau decay modes have been performed using a realistic simulation
of the expected detector performance. The results obtained demonstrate the
large discovery potential in the H -> WW decay channel and the sensitivity to
Higgs boson decays into tau-pairs in the low-mass region around 120 GeV.Comment: 20 pages, 13 ps figures, uses EPJ style fil
Generic User Process Interface for Event Generators
Generic Fortran common blocks are presented for use by High Energy Physics
event generators for the transfer of event configurations from parton level
generators to showering and hadronization event generators.Comment: Physics at TeV Colliders II Workshop, Les Houches, France, May 2001
14 pages, 6 figure
Stress distribution of faceted particles in a silo after its partial discharge
We present experimental and numerical results of the effect that a partial discharge has on the morphological and micro-mechanical properties of non-spherical, convex particles in a silo. The comparison
of the particle orientation after filling the silo and its subsequent partial discharge reveals important shearinduced
orientation, which affects stress propagation. For elongated particles, the flow induces an increase in the packing disorder which leads to a reduction of the vertical stress propagation developed during the deposit generated prior to the partial discharge. For square particles, the flow favors particle alignment with the lateral walls promoting a behavior opposite to the one of the elongated particles: vertical force transmission, parallel to gravity, is induced. Hence, for elongated particles the flow developed during the partial discharge of the silo leads to force saturation with depth whereas for squares the flow induces
hindering of the force saturation observed during the silo filling
Electron and Photon Energy Deposition in Universe
We consider energy deposition of high energy electrons and photons in
universe. We carry out detailed calculations of fractions of the initial energy
of the injected electron or photon which are used to heat, ionize and excite
background plasma in the early universe for various ionization states and
redshifts.Comment: 21 pages, 12 figure
Antagonistic action of Agrobacterium tumefaciens and essential oils against Aspergillus flavus isolates from Bertholletia excelsa (brasil-nuts).
The chestnut-do-brasil (Bertholletia excelsa) is a tree found in the Amazon region, whose fruit called ?the Brazil nut? has an important role in regional economy. Such seeds are affected by the growth of several fungi that produce mycotoxins. The fungus Aspergillus flavus is the main producer of aflatoxins, compromising the nuts. The main objective of this study was study the growth inhibitory action of A. flavus by essential oils of rosemary, anise, beta-caryophyllene, cinnamon, lemongrass, clove, eucalyptus, limonene, mint-citrata and thyme. The culture medium used was the LB, and the incubation was performed at 28°C for 48 hours in the presence of 10μL of the respective oils. Simultaneously, were tested the Agrobacterium tumefaciens and yeasts as possible agents for controlling A. flavus. The results point to a more effective inhibitory activity of essential oils of rosemary, anise, mint-citrata, eucaliptus, lemongrass, thyme, beta-caryophylelene and limonene. Cinnamon and clove oils were unable to inhibit the growth of A. flavus strains. The A. tumefaciens was able to inhibit 16 of 70 A. flavus strains, but is not recorded any inhibition by yeasts
Amazonian plant crude extract screening for activity against multidrug-resistant bacteria.
Antimicrobial resistance is a subject of great concern in public health and also in the designing of strategies for current therapeutic protocols all over the world. New drugs, including those necessary for a reserve armamentarium and exhibiting less side effects deserve special attention. In rural areas, particularly in Brazil, a huge number of natural products, in different artisanal preparations, mainly from plants, have been used by traditional populations to cure diseases. Despite some of these plants have been studied, many of them are awaiting to have their compounds chemically characterized and investigated their pharmacodynamics properties. Further, as well known, the environment plays a crucial role in the metabolism of these plants, yielding different and varied molecular complexes depending on the period of collection, climate conditions, kind of soil and also the plant speciation. In this report, ethanol crude extract of 10 different botanical specimens from the Amazon region of Brazil, in the Amapa State, were screened for antibacterial activity of 7 clinical resistant microorganisms utilizing as control ATCC bacterial species by the Kirby-Bauer method. Plant extracts of Geissospermum argenteum, Uncaria guianensis, Brosimum acutifolium, Copaifera reticulate, Licania macrophylla, Ptycopetalum olacoides and Dalbergia subcymosa yielded activity against Staphylococcus aureus and Pseudomonas aeruginosa, both multidrug resistant, and Staphylococcus aureus ATCC strain.Disponivel também on line
CaracterĂsticas fĂsico-quĂmicas dos principais solos na AmazĂ´nia.
bitstream/item/220362/1/CPAF-AP-2020-cap-3-Caracteristicas-fisico.pd
Antimicrobial activity of amazonian medicinal plants.
The aqueous extracts of currently utilized Amazonian medicinal plants were assayed in vitro searching for antimicrobial activity against human and animal pathogenic microorganisms. Medium resuspended lyophilized aqueous extracts of different organs of Amazonian medicinal plants were assayed by in vitro screening for antimicrobial activity. ATCC and standardized microorganisms obtained from Oswaldo Cruz Foundation/Brazil were individually and homogeneously grown in agar plate, and holes previously perforated in the gel were filled with diluted plant aqueous extracts. Inhibition halos were evaluated and controlled by the use of the fluoroquinolone ciprofloxacin. The Amazonian medicinal plants, Hymenelobium petraeum showed inhibitory activity over Staphylococcus aureus, Enterococcus faecalis, Salmonella enterica serovar Typhi, Acinetobacter baumannii and Candida albicans, while Vatairea guianensis and Symphonia globulifera presented inhibitory activity exclusively for Staphylococcus aureus. Also, Ptychopetalum olacoides and Pentaclethra macroloba inhibited the growth of Klebsiella ozaenae and Acinetobacter baumannii. The aqueous botanic extracts that showed activity against microroganisms of ATTC and Osvaldo Cruz strains had at least 40% of antimicrobial activity when compared to halo inhibition produced by the commercial antibiotic ciprofloxacin utilized as a control. Of all plants extracts assayed, the Hymenelobium petraeum had the best performance, sometimes exhibiting higher activity than ciprofloxacin. It is not well-defined by the physicians the exact indication of the majority of medicinal plants in the Amazon area in Brazil. Natives utilize the plants according to their symptoms, based on the traditional knowledge transmitted orally from generation to generation, among Amerindians, Afrodescendents and ethnic mixed populations. A significant number of Amazonian medicinal plants are totally unknown related to their medicinal properties including mechanism of action and therapeutic effects, as very few information is reported in the scientific literature. A tiny amount of data is presented, as the preliminary antimicrobial properties of the medicinal plants here accessed, under the urgent necessity of new antibiotics in the market and in face of the increased resistance of infectious microorganisms to antimicrobials
Implications of the Fermi-LAT diffuse gamma-ray measurements on annihilating or decaying Dark Matter
We analyze the recently published Fermi-LAT diffuse gamma-ray measurements in
the context of leptonically annihilating or decaying dark matter (DM) with the
aim to explain simultaneously the isotropic diffuse gamma-ray and the PAMELA,
Fermi and HESS (PFH) anomalous data. Five different DM
annihilation/decay channels , , , , or (the latter
two via an intermediate light particle ) are generated with PYTHIA. We
calculate both the Galactic and extragalactic prompt and inverse Compton (IC)
contributions to the resulting gamma-ray spectra. To find the Galactic IC
spectra we use the interstellar radiation field model from the latest release
of GALPROP. For the extragalactic signal we show that the amplitude of the
prompt gamma-emission is very sensitive to the assumed model for the
extragalactic background light. For our Galaxy we use the Einasto, NFW and
Isothermal DM density profiles and include the effects of DM substructure
assuming a simple subhalo model. Our calculations show that for the
annihilating DM the extragalactic gamma-ray signal can dominate only if rather
extreme power-law concentration-mass relation is used, while more
realistic relations make the extragalactic component comparable or
subdominant to the Galactic signal. For the decaying DM the Galactic signal
always exceeds the extragalactic one. In the case of annihilating DM the PFH
favored parameters can be ruled out only if power-law relation is
assumed. For DM decaying into or the PFH favored DM parameters
are not in conflict with the Fermi gamma-ray data. We find that, due to the
(almost) featureless Galactic IC spectrum and the DM halo substructure,
annihilating DM may give a good simultaneous fit to the isotropic diffuse
gamma-ray and to the PFH data without being in clear conflict with the
other Fermi-LAT gamma-ray measurements.Comment: Accepted for publication in JCAP, added missing references, new Figs.
9 \& 10, 35 page
The QCD/SM Working Group: Summary Report
This Report documents the results obtained by the Working Group on Quantum
ChromoDynamics and the Standard Model for the Workshop ``Physics at TeV
Colliders'', Les Houches, France, 21 May - 1 June 2001. The account of
uncertainties in Parton Distribution Functions is reviewed. Progresses in the
description of multiparton final states at Next-to-Leading Order and the
extension of calculations for precision QCD observables beyond this order are
summarized. Various issues concerning the relevance of resummation for
observables at TeV colliders is examined. Improvements to algorithms of jet
reconstruction are discussed and predictions for diphoton and photon pi-zero
production at the LHC are made for kinematic variables of interest regarding
searches for a Higgs boson decaying into two photons. Finally, several
improvements implemented in Monte-Carlo event generators are documented
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