9,415 research outputs found
Renormalization of chiral nuclear forces with multiple subtractions in peripheral channels
We analyse the renormalization of the of two-nucleon interaction with
multiple subtractions in peripheral waves considering two chiral forces at
N3LO. Phase shifts at low energies are then computed with several subtraction
points below \mu = 10 / fm. We show that for most peripheral waves the phase
shifts have nearly no dependence on the renormalization scale. In two cases the
phase shifts converge slowly as the renormalization scale approaches \mu = 1 /
fm and in one case the phase shifts presented oscillations with respect to the
subtraction point \mu.Comment: 21 pages, 12 figures, to appear in the special issue "Few-Body
Systems in High Energy Physics" (AHEP
Natural groundwater quality and health
Natural groundwater composition and quality is of concern because it is used worldwide as a freshwater supply. Discarding artificial pollution, epidemiological studies have shown that many communities suffer important diseases linked to the groundwater ingested since several tens of years ago. As the available resources of freshwater decrease due to pollution and overexploitation, and the need of water increases, more efforts have to be devoted to guarantee water quality. Of course preventing pollution is the main task but studying and controlling the natural groundwater quality is also very important, mainly in developing countries. To study the relationship between natural groundwater composition and health implies working in many scientific disciplines such as hydrology, geology, geochemistry and toxicology. During its cycle, water acquires its natural composition depending on the hydrogeological scenario, which, in turn, depends on the climate, topography and rock properties (hydraulic properties, chemical composition). Nearly all natural waters contain traces of most chemical elements but often at extremely low concentrations. Major species invariably make up over 99% of the solute content. Major compounds as well as trace elements can be essential, toxic, potentially toxic and potentially beneficial. Special attention has to be paid to chemical elements present in many natural waters whose insufficient or excess intake produces critical illness and whose intake is mainly through the ingestion of water. A first approach to groundwater quality can be made using element concentrations in water but many efforts have to be devoted to perform epidemiological and risk assessment studies based on intake doses of chemical species
Complementary action of chemical and electrical synapses to perception
Acknowledgements This study was possible by partial financial support from the following agencies: Fundação Araucária, EPSRC-EP/I032606/1, CNPq No. 441553/2014-1, CAPES No. 17656-12-5 and Science Without Borders Program— Process Nos. 17656125, 99999.010583/2013-00 and 245377/2012-3.Peer reviewedPostprin
Spatial organisation plasticity reduces disease infection risk in rock-paper-scissors models
We study a three-species cyclic game system where organisms face a contagious
disease whose virulence may change by a pathogen mutation. As a responsive
defence strategy, organisms' mobility is restricted to reduce disease
dissemination in the system. The impact of the collective self-preservation
strategy on the disease infection risk is investigated by performing stochastic
simulations of the spatial version of the rock-paper-scissors game. Our
outcomes show that the mobility control strategy induces plasticity in the
spatial patterns with groups of organisms of the same species inhabiting
spatial domains whose characteristic length scales depend on the level of
dispersal restrictions. The spatial organisation plasticity allows the
ecosystems to adapt to minimise the individuals' disease contamination risk if
an eventual pathogen alters the disease virulence. We discover that if a
pathogen mutation makes the disease more transmissible or less lethal, the
organisms benefit more if the mobility is not strongly restricted, thus forming
large spatial domains. Conversely, the benefits of protecting against a
pathogen causing a less contagious or deadlier disease are maximised if the
average size of groups of individuals of the same species is significantly
limited, reducing the dimensions of groups of organisms significantly. Our
findings may help biologists understand the effects of dispersal control as a
conservation strategy in ecosystems affected by epidemic outbreaks.Comment: 8 pages, 8 figure
Running of the contact interactions in chiral N3LO potentials from subtractive renormalization
In this work a subtracted kernel renormalization procedure (SKM) is applied to the chiral NN potential up to next-to-next-to-next-to-leading-order ((NLO)-L-3) to obtain the running of the renormalized contact strengths with the subtraction scale mu and the phase shifts for all uncoupled waves with contact interaction (S, P, D). We use two potentials constructed within the framework of Weinberg's approach to ChEFT, which provide a very accurate description of NN scattering data below laboratory energies E similar to 350 MeV, namely Epelbaum, Glockle and Meissner (N3LO-EGM) and Entem and Machleidt (N3LO-EM). For both potentials, we consider a large cutoff (30 fm(-1)) and analyze the phases and the running of the contact strengths with the subtraction point mu by making a fit of the K-matrix with five subtractions to the K-matrix from the Nijmegen II potential at low energies (E <= 20 MeV).In this work a subtracted kernel renormalization procedure (SKM) is applied to the chiral NN potential up to next-to-next-to-next-to-leading-order (N 3 LO) to obtain the running of the renormalized contact strengths with the subtraction scale μ and the ph630FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOsem informaçãosem informação37th Brazilian Meeting on Nuclear PhysicsS.S. is partially supported by FAPESP and V.S.T. would like to thank FAEPEX, FAPESP and CNPq for financial support
Searching for solar siblings among the HARPS data
The search for the solar siblings has been particularly fruitful in the last
few years. Until now, there are four plausible candidates pointed out in the
literature: HIP21158, HIP87382, HIP47399, and HIP92831. In this study we
conduct a search for solar siblings among the HARPS high-resolution FGK dwarfs
sample, which includes precise chemical abundances and kinematics for 1111
stars. Using a new approach based on chemical abundance trends with the
condensation temperature, kinematics, and ages we found one (additional)
potential solar sibling candidate: HIP97507.Comment: 4 pages, 2 figures, 1 table. Accepted in A&
Geometric Frustration and Dimensional Reduction at a Quantum Critical Point
We show that the spatial dimensionality of the quantum critical point
associated with Bose--Einstein condensation at T=0 is reduced when the
underlying lattice comprises a set of layers coupled by a frustrating
interaction. Our theoretical predictions for the critical temperature as a
function of the chemical potential correspond very well with recent
measurements in BaCuSiO [S. E. Sebastian \textit{et al}, Nature
\textbf{411}, 617 (2006)].Comment: 5 pages, 2 figure
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