8,694 research outputs found
Macroscopic fluctuations theory of aerogel dynamics
We consider the thermodynamic potential describing the macroscopic
fluctuation of the current and local energy of a general class of Hamiltonian
models including aerogels. We argue that this potential is neither analytic nor
strictly convex, a property that should be expected in general but missing from
models studied in the literature. This opens the possibility of describing in
terms of a thermodynamic potential non-equilibrium phase transitions in a
concrete physical context. This special behaviour of the thermodynamic
potential is caused by the fact that the energy current is carried by particles
which may have arbitrary low speed with sufficiently large probability.Comment: final versio
Numerical Implementation of lepton-nucleus interactions and its effect on neutrino oscillation analysis
We discuss the implementation of the nuclear model based on realistic nuclear
spectral functions in the GENIE neutrino interaction generator. Besides
improving on the Fermi gas description of the nuclear ground state, our scheme
involves a new prescription for selection, meant to efficiently enforce
energy momentum conservation. The results of our simulations, validated through
comparison to electron scattering data, have been obtained for a variety of
target nuclei, ranging from carbon to argon, and cover the kinematical region
in which quasi elastic scattering is the dominant reaction mechanism. We also
analyse the influence of the adopted nuclear model on the determination of
neutrino oscillation parameters.Comment: 19 pages, 35 figures, version accepted by Phys. Rev.
Discontinuous Euler instability in nanoelectromechanical systems
We investigate nanoelectromechanical systems near mechanical instabilities.
We show that quite generally, the interaction between the electronic and the
vibronic degrees of freedom can be accounted for essentially exactly when the
instability is continuous. We apply our general framework to the Euler buckling
instability and find that the interaction between electronic and vibronic
degrees of freedom qualitatively affects the mechanical instability, turning it
into a discontinuous one in close analogy with tricritical points in the Landau
theory of phase transitions.Comment: 4+ pages, 3 figures, published versio
Efeito do glyphosate sobre parâmetros fisiológicos de Conyza sumatrensis.
Editores tĂ©cnicos: Joseani Mesquita Antunes, Ana LĂdia Variani Bonato, Márcia Barrocas Moreira Pimentel
NMR and SR detection of unconventional spin dynamics in Er(trensal) and Dy(trensal) molecular magnets
Measurements of proton Nuclear Magnetic Resonance (1H NMR) spectra and
relaxation and of Muon Spin Relaxation (SR) have been performed as a
function of temperature and external magnetic field on two isostructural
lanthanide complexes, Er(trensal) and Dy(trensal) featuring
crystallographically imposed trigonal symmetry. Both the nuclear 1/T1 and muon
longitudinal relaxation rates, LRR, exhibit a peak for temperatures T
lower than 30K, associated to the slowing down of the spin dynamics, and the
width of the NMR absorption spectra starts to increase significantly at T ca.
50K, a temperature sizably higher than the one of the LRR peaks. The LRR peaks
have a field and temperature dependence different from those previously
reported for all Molecular Nanomagnets. They do not follow the
Bloembergen-Purcell-Pound scaling of the amplitude and position in temperature
and field and thus cannot be explained in terms of a single dominating
correlation time c determined by the spin slowing down at low
temperature. Further, for T lower than 50K the spectral width does not follow
the temperature behavior of the magnetic susceptibility chi. We suggest, using
simple qualitative considerations, that the observed behavior is due to a
combination of two different relaxation processes characterized by the
correlation times LT and HT, dominating for T lower than 30K and T
higher than 50K, respectively. Finally, the observed flattening of LRR for T
lower than 5K is suggested to have a quantum origin
single nucleotide polymorphism discovery in the avian tapasin gene
Abstract Tapasin is a transmembrane glycoprotein located in the endoplasmic reticulum. Its function is to assist the assembly of major histocompatibility complex class I molecules. The chicken Tapasin gene includes 8 exons and is localized inside the major histocompatibility complex between the 2 class IIβ genes. The aim of the current study was the estimation of single nucleotide polymorphism frequency within the avian Tapasin gene. The Tapasin gene sequence from exon 5 to exon 6 was amplified for the chicken, turkey, and pheasant, and sequences of different lengths were obtained. The sequence analysis based on PolyBayes identified 25 putative single nucleotide polymorphism sites when the 3 species were compared. The coding sequences were further translated and analyzed to identify amino acid substitutions. The results indicated that polymorphisms within this region of the gene was mainly observed in the heterozygous state. The level of conservation of the Tapasin gene sequence among species is likely to be related to the functional importance of the gene
Estádio de desenvolvimento e superfĂcie foliar reduzem a eficiĂŞncia de chlorimuron-ethyl e glyphosate em Conyza sumatrensis.
Editores tĂ©cnicos: Joseani Mesquita Antunes, Ana LĂdia Variani Bonato, Márcia Barrocas Moreira Pimentel
Parametric amplification of magnetoplasmons in semiconductor quantum dots
We show that the magnetoplasmon collective modes in quasi-two-dimensional
semiconductor quantum dots can be parametrically amplified by periodically
modulating the magnetic field perpendicular to the nanostructure. The two
magnetoplasmon modes are excited and amplified simultaneously, leading to an
exponential growth of the number of bosonic excitations in the system. We
further demonstrate that damping mechanisms as well as anharmonicities in the
confinement of the quantum dot lead to a saturation of the parametric
amplification. This work constitutes a first step towards parametric
amplification of collective modes in many-body fermionic systems beyond one
dimension.Comment: 12 pages, 5 figures; published versio
Overview of the benefitsand potential issues of the nonavalent HPV vaccine
HPV-related diseases affect anogenital and oropharyngeal regions, heavily affecting the psychosexual dimension of both male and female individuals. HPV vaccination programs based on a bivalent or quadrivalent vaccine have opened broad perspectives for primary prevention. A nonavalent HPV vaccine (9vHPV), covering nine genotypes (HPV6, HPV11, HPV16, HPV18, HPV31, HPV33, HPV45, HPV52, and HPV58), might provide further improvement in terms of direct protection. In the present report, efficacy and safety data from 9vHPV vaccine development programs are examined.
Efficacy data come from a pivotal trial, which was conducted among women aged 16–26 years randomly assigned to receive either the 9vHPV or the quadrivalent HPV (4vHPV) vaccine. The 9vHPV vaccine was shown to have potential benefits as compared with 4vHPV, increasing the overall estimated rate of prevention to 90% for cervical cancer and up to 80% for precancerous cervical lesions. For all other HPV-related
pre-invasive and invasive lesions, 9vHPV showed potentially greater disease reduction, depending on the anatomic region examined. Thus, the 9vHPV vaccine
shows clinical potential for the prevention of HPV-related diseases in both sexes.
Future adoption of 9vHPV will depend on factors including market price, cost-effectiveness data, use of a two-dose schedule, and safety and efficacy monitoring in real-life programs
Suscetibilidade diferencial de biĂłtipos de Conyza sumatrensis ao herbicida chlorimuron-ethyl.
Editores tĂ©cnicos: Joseani Mesquita Antunes, Ana LĂdia Variani Bonato, Márcia Barrocas Moreira Pimentel
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