1,165 research outputs found
Perturbation theory vs. simulation for tadpole improvement factors in pure gauge theories
We calculate the mean link in Landau gauge for Wilson and improved SU(3)
anisotropic gauge actions, using two loop perturbation theory and Monte Carlo
simulation employing an accelerated Langevin algorithm. Twisted boundary
conditions are employed, with a twist in all four lattice directions
considerably improving the (Fourier accelerated) convergence to an improved
lattice Landau gauge. Two loop perturbation theory is seen to predict the mean
link extremely well even into the region of commonly simulated gauge couplings
and so can be used remove the need for numerical tuning of self-consistent
tadpole improvement factors. A three loop perturbative coefficient is inferred
from the simulations and is found to be small. We show that finite size effects
are small and argue likewise for (lattice) Gribov copies and double Dirac
sheets.Comment: 13 pages of revtex
La bioprospecciĂłn en nicaragua: avances en la bĂșsqueda de aplicaciones agrĂcolas, industriales y ambientales
Nicaragua belongs to one of the mega diversity blocs of the world. Since it is considering to be a geographic bridge, it possesses a privileged tropical position that translates into more than 20 different rich ecosystems in biodiversity. Due to bio-prospecting we understand the research in order to identify species, variety, genes and products with potential or actuals current uses for the human beings. The bio-prospecting advances reported in this article, has permitted until to date, to obtain 92 isolated forms in the Pedro Lazo cheese handcrafted company (76 bacterial, 3 yeast fungus type and 13 isolate filamentous fungus type). A total of 68 isolate in the handcrafted mine from la Libertad, Chontales (44 isolated bacterial, 6 yeast fungus type and 18 isolated filamentous funguses type). From the ecological reserve, El Chocoyero / El Brujo, 44 pure isolated were obtained (22 bacterial and 22 filamentous fungus). Finally; from Rio Chiquito in Leon city, 51 pure isolated were obtained (43 isolated bacterial, 7 filamentous fungi and 1 yeast fungi type). In summary: 255 isolate were obtained between bacterial, filamentous fungus and fungi yeast type, in which we expect to find many isolated with enormous biotechnological potentials.Nicaragua pertenece a uno de los bloques de mega diversidad del mundo. Se considera que por ser un puente geogrĂĄfico posee una posiciĂłn tropical privilegiada que se traduce en mĂĄs de 20 diferentes ecosistemas ricos en biodiversidad. Por BioprospecciĂłn entendemos la investigaciĂłn realizada para identificar especies, variedades, genes y productos con usos actuales o potenciales por parte de la humanidad. Los trabajos de BioprospecciĂłn reportados por medio de estos avances, han permitido que la fecha se cuente con 92 aislados de la quesera artesanal Pedro lazo (76 bacterias, 3 hongos levaduriformes y 13 aislados de hongos filamentosos). Un total de 68 aislados de las minas artesanales de La Libertad, Chontales (44 aislados bacterianos, 6 hongos levaduriformes y 18 aislados de hogos filamentosos). De la reserva ecolĂłgica El Chocoyero / El Brujo, se obtuvieron 44 aislados puros (22 son bacterias y los otros 22 son hongos filamentosos). Finalmente; Del RĂo Chiquito en la ciudad de LeĂłn, se obtuvo 51 aislados puros (43 son aislados bacterianos, 7 son hongos filamentosos y 1 es un hongo levaduriforme). Para un gran total de: 255 aislados entre bacterias, hongos filamentosos y levaduriformes, entre los cuales se espera encontrar muchos con enormes potencialidades biotecnolĂłgicas
Prospection of sustainable agrifood systems based on discourse analysis of Curraleiro PĂ©-Duro cattle breeders in Brazil
ABSTRACT Developing countries face great challenges to couple agricultural intensification and sustainable supply chain development. This paper explores the opportunities for innovation in the conservation of the locally adapted Curraleiro PĂ©-Duro (CPD) cattle. The CPD is a historical Brazilian breed, related to regional culture, which exhibits remarkable adaptability in tropical biomes. The research method consisted of interviewing and analyzing the discourse of CPD breeders in Tocantins, Brazil. The systematization of the data resulted in four categories and eleven subcategories, which were defined a posteriori. Our findings reveal motivational aspects, potentialities, and prospects for valuation, besides the needs and perceived challenges faced by CPD farmers. A better understanding of the current situation may guide public policies, encourage stakeholders, benefit farmers, and lead to sustainable agri-food initiatives. The empirical contributions of our diagnosis are discussed, and we show how they bring forward and provide valuable lessons to prospect innovations in the conservation of CPD cattle. These findings may support scholars and people who are also interested in accessing and supporting the conservation of indigenous livestock. In general, the study supports the definition of strategies, planning, and investments for the value chain, including the participation of upstream and downstream segments of the farms
On Aharonov-Casher bound states
In this work bound states for the Aharonov-Casher problem are considered.
According to Hagen's work on the exact equivalence between spin-1/2
Aharonov-Bohm and Aharonov-Casher effects, is known that the
term cannot be neglected in the
Hamiltonian if the spin of particle is considered. This term leads to the
existence of a singular potential at the origin. By modeling the problem by
boundary conditions at the origin which arises by the self-adjoint extension of
the Hamiltonian, we derive for the first time an expression for the bound state
energy of the Aharonov-Casher problem. As an application, we consider the
Aharonov-Casher plus a two-dimensional harmonic oscillator. We derive the
expression for the harmonic oscillator energies and compare it with the
expression obtained in the case without singularity. At the end, an approach
for determination of the self-adjoint extension parameter is given. In our
approach, the parameter is obtained essentially in terms of physics of the
problem.Comment: 11 pages, matches published versio
Cardamonin, a schistosomicidal chalcone from Piper aduncum L. (Piperaceae) that inhibits Schistosoma mansoni ATP diphosphohydrolase
AbstractBackground: Schistosomiasis is one of the world's major public health problems, and praziquantel (PZQ) is the only available drug to treat this neglected disease with an urgent demand for new drugs. Recent studies indicated that extracts from Piper aduncum L. (Piperaceae) are active against adult worms of Schistosoma mansoni, the major etiological agent of human schistosomiasis.Purpose: We investigated the in vitro schistosomicidal activity of cardamonin, a chalcone isolated from the crude extract of P. aduncum. Also, this present work describes, for the first time, the S. mansoni ATP diphosphohydrolase inhibitory activity of cardamonin, as well as, its molecular docking with S. mansoni ATPDase1, in order to investigate its mode of inhibition.Methods: In vitro schistosomicidal assays and confocal laser scanning microscopy were used to evaluate the effects of cardamonin on adult schistosomes. Cell viability was measured by MTT assay, and the S. mansoni ATPase activity was determined spectrophotometrically. Identification of the cardamonin binding site and its interactions on S. mansoni ATPDase1 were made by molecular docking experiments.Results: A bioguided fractionation of the crude extract of P. aduncum was carried out, leading to identification of cardamonin as the active compound, along with pinocembrin and uvangoletin. Cardamonin (25, 50, and 100 ”M) caused 100% mortality, tegumental alterations, and reduction of oviposition and motor activity of all adult worms of S. mansoni, without affecting mammalian cells. Confocal laser scanning microscopy showed tegumental morphological alterations and changes on the numbers of tubercles of S. mansoni worms in a dose-dependent manner. Cardamonin also inhibited S. mansoni ATP diphosphohydrolase (IC50 of 23.54 ”M). Molecular docking studies revealed that cardamonin interacts with the Nucleotide-Binding of SmATPDase 1. The nature of SmATPDase 1âcardamonin interactions is mainly hydrophobic and hydrogen bonding.Conclusion: This report provides evidence for the in vitro schistosomicidal activity of cardamonin and demonstrated, for the first time, that this chalcone is highly effective in inhibiting S. mansoni ATP diphosphohydrolase, opening the route to further studies of chalcones as prototypes for new S. mansoni ATP diphosphohydrolase inhibitors
An IRAK1-PIN1 signalling axis drives intrinsic tumour resistance to radiation therapy
Drug-based strategies to overcome tumour resistance to radiotherapy (R-RT) remain limited by the single-agent toxicity of traditional radiosensitizers (for example, platinums) and a lack of targeted alternatives. In a screen for compounds that restore radiosensitivity in p53 mutant zebrafish while tolerated in non-irradiated wild-type animals, we identified the benzimidazole anthelmintic oxfendazole. Surprisingly, oxfendazole acts via the inhibition of IRAK1, a kinase thus far implicated in interleukin-1 receptor (IL-1R) and Toll-like receptor (TLR) immune responses. IRAK1 drives R-RT in a pathway involving IRAK4 and TRAF6 but not the IL-1R/TLR-IRAK adaptor MyD88. Rather than stimulating nuclear factor-ÎșB, radiation-activated IRAK1 prevented apoptosis mediated by the PIDDosome complex (comprising PIDD, RAIDD and caspase-2). Countering this pathway with IRAK1 inhibitors suppressed R-RT in tumour models derived from cancers in which TP53 mutations predict R-RT. Moreover, IRAK1 inhibitors synergized with inhibitors of PIN1, a prolyl isomerase essential for IRAK1 activation in response to pathogens and, as shown here, in response to ionizing radiation. These data identify an IRAK1 radiation-response pathway as a rational chemoradiation therapy target
The Temporal Pattern of Mating Behavior of the Fruit Fly, Anastrepha zenildae in the Laboratory
The state of Rio Grande do Norte is an important fruit-producing and exporting area in northeastern Brazil. The success of this industry depends on fruit fly population control, especially in fly-free exporting zones. However, many fruits are not exported because of quarantine restrictions imposed by importing countries. A survey in the state has detected a considerable increase of the fruit fly, Anastrepha zenildae Zucchi (Diptera: Tephritidae), probably a result of the introduction of irrigated guava orchards that make fruit available all year. Knowledge of the sexual behavior of Tephritidae has great importance to pest control programs, particularly those that employ the Sterile Insect Technique. In order to characterize the reproductive behavior of A. zenildae, 32 individuals (16 males; 16 females) in each of six generations were submitted to an artificial 12:12 L:D cycle (750: < 1 lux, lights on 07:00â19:00) and observed over their lifetimes. The courtship and copulation occurred in leks and the episodes varied with the time of day, courtship being most frequent between Zeitgeber time (ZT) 3 and ZT 7, peaking at ZT 5â6. Copulations occurred between ZT 2 and ZT 8, with a higher frequency between ZT 5â7 and a peak at ZT 6. Mean duration was 0.28 ± 0.03 min/male (range: 5â163 min). Males in the leks attempted to copulate mainly between ZT 3 and ZT 7 with a peak at ZT 6, and males outside leks peaked at ZT 7. The different timing of sexual behaviors among related sympatric species, including A. zenildae, may contribute to species isolation
Search for the standard model Higgs boson in tau final states
We present a search for the standard model Higgs boson using hadronically
decaying tau leptons, in 1 inverse femtobarn of data collected with the D0
detector at the Fermilab Tevatron ppbar collider. We select two final states:
tau plus missing transverse energy and b jets, and tau+ tau- plus jets. These
final states are sensitive to a combination of associated W/Z boson plus Higgs
boson, vector boson fusion and gluon-gluon fusion production processes. The
observed ratio of the combined limit on the Higgs production cross section at
the 95% C.L. to the standard model expectation is 29 for a Higgs boson mass of
115 GeV.Comment: publication versio
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