Neutron-proton mass difference in nuclei in a relativistic harmonic quark model

The nuclear dependence of the neutron-proton mass difference is examined in a relativistic harmonic quark model with the assumption of a swelling of the individual nucleon originated by a decrease of the spring constant inside the nuclear medium. A decrease of the neutron-proton mass difference is obtained which is reasonably small and in the right direction to cope with the Nollen-Schiffer anomaly in mirror nuclei. © 1992 Società Italiana di Fisica.

Flattening of the resonance spectrum of hadrons from κ-deformed Poincaré algebra

Recently Lukierski et al. [1] defined a κ-deformed Poincaré algebra which is characterized by having the energy-momentum and angular momentum sub-algebras not deformed. Further Biedenharn et al. [2] showed that on gauging the κ-deformed electron with the electromagnetic field, one can set a limit on the allowed value of the deformation parameter ∈ ≡ 1/κ < 1 fm. We show that one gets Regge like angular excitations, J, of the mesons, non-strange and strange baryons, with a value of ∈ ∼ 0.082 fm and predict a flattening with J of the corresponding trajectories. The Regge fit improves on including deformation, particularly for the baryon spectrum.

Autism spectrum disorder in a girl with a de novo x;19 balanced translocation

Balanced X-autosome translocations are rare, and female carriers are a clinically heterogeneous group of patients, with phenotypically normal women, history of recurrent miscarriage, gonadal dysfunction, X-linked disorders or congenital abnormalities, and/or developmental delay. We investigated a patient with a de novo X;19 translocation. The six-year-old girl has been evaluated due to hyperactivity, social interaction impairment, stereotypic and repetitive use of language with echolalia, failure to follow parents/caretakers orders, inconsolable outbursts, and persistent preoccupation with parts of objects. The girl has normal cognitive function. Her measurements are within normal range, and no other abnormalities were found during physical, neurological, or dysmorphological examinations. Conventional cytogenetic analysis showed a de novo balanced translocation, with the karyotype 46,X,t(X;19)(p21.2;q13.4). Replication banding showed a clear preference for inactivation of the normal X chromosome. The translocation was confirmed by FISH and Spectral Karyotyping (SKY). Although abnormal phenotypes associated with de novo balanced chromosomal rearrangements may be the result of disruption of a gene at one of the breakpoints, submicroscopic deletion or duplication, or a position effect, X; autosomal translocations are associated with additional unique risk factors including X-linked disorders, functional autosomal monosomy, or functional X chromosome disomy resulting from the complex X-inactivation process.

Sociocognitive performance in autism spectrum disorders and interference of the therapeutic environment

To analyze the sociocognitive performance of children and adolescents with autism spectrum disorders in two environments of language therapy, which differ as to the physical structure. Ten children and adolescents with ages between 4 and 13 years, of both genders, diagnosed with autism spectrum disorders took part in the study. For data collection, eight filming sessions were performed during individual language therapy lasting 30 minutes, being four in a room with conventional environmental organization (common room) and four in a room with specific ambiance [children's interaction core (CIC) room], interspersed during a month. For the analysis of filmed situations, the Sociocognitive Performance Protocol was used and obtained data were subjected to statistical analysis. No statistical significance was found in sociocognitive performance of 10 subjects in the common and CIC rooms, although specific differences were observed in some cases. The creation of preestablished physical environments or specific materials is not and should not be considered essential for language therapy. It is noteworthy, however, that the absence of a large volume of statistically significant data does not indicate that the results are not expressive, reiterating the need for further research in the area.

Higher algebras and mesonic spectrum in two-dimensional QCD

We construct composite operators in two-dimensional bosonized QCD, which obey a W∞ algebra, and discuss their relation to analogous objects recently obtained in the fermionic language. A complex algebraic structure is unravelled, supporting the idea that the model is integrable. For singlets we find a mass spectrum obeying the Regge behavior.

Medium effects in the pion-pole mechanism [gamma gamma ->pi(0)->nu(R)(nu)over-bar(L)(nu(L)(nu)over-bar(R))] of neutron star cooling

Nuclear medium effects in the neutrino cooling of neutron stars through the reaction channel γγ→π0 →ν Rν̄L(νLν̄R) are incorporated. Throughout the paper we discuss different possibilities of right-handed neutrinos, massive left-handed neutrinos, and standard massless left-handed neutrinos (reaction is then allowed only with medium modified vertices). It is demonstrated that multiparticle effects suppress the rate of this reaction channel in the dense hadron matter by 6-7 orders of magnitude that does not allow to decrease existing experimental upper limit on the corresponding π0νν̄ coupling. Other possibilities of the manifestation of the given reaction channel in different physical situations, e.g., in the quark color superconducting cores of the most massive neutron stars, are also discussed. We demonstrate that in the color-flavor-locked superconducting phase for temperatures T≲ 0.1-10 MeV (depending on the effective pion mass and the decay width) the process is feasibly the most efficient neutrino cooling process, although the absolute value of the reaction rate is rather small.

Impact of Solvent Quality on the Density Profiles of Looped Triblock Copolymer Brushes by Neutron Reflectivity Measurements

Preferential adsorption of poly(2-vinylpyridine)-deuterated polystyrene-poly(2-vinylpyridine) (PVP-dPS-PVP) triblock copolymers from toluene onto silicon leads to the formation of dPS loops tethered by the PVP end blocks. Using neutron reflectometry, we have determined the segment density profiles of these looped polymer brushes in toluene, a good solvent for the dPS block, and in cyclohexane at 20 °C (poor solvent), 32 °C, (near-Θ solvent), and 50 °C (marginal solvent). While the swelling behavior qualitatively agrees with that observed for singly grafted brushes, there are interesting differences in the local structural details: In a good solvent, the segment density profiles are composed of an inner parabolic region and a long, extended tail. In cyclohexane, the profiles are described by exponential decays. We ascribe these features to a novel polydispersity effect that arises due to tethering the PS loops by both ends. The results also show that the less dense layers undergo more significant changes in swollen height as solvent quality is changed and that the looped brushes of different molecular weight, asymmetry, and tethering density adhere to scaling relationships derived for lightly cross-linked polymer gels.

Social Cognition and Interaction Training (SCIT) for Individuals with Schizophrenia Spectrum Disorders in Outpatient Treatment Settings

The role of social cognition in severe mental illness (SMI) has gained much attention, especially over the last decade. The impact of deficits in socio-cognitive functioning has been found to have detrimental effects on key areas of day-to-day functioning in individuals with SMI, such as gaining and maintaining employment and overall experienced quality of life. Treatment of individuals with SMI is challenging, as the presentation of individual signs and symptoms is rather heterogeneous. There are several treatment approaches addressing deficits ranging from broader social and interpersonal functioning to neurocognitive and more intrapersonal functioning. As research in the domain of social cognition continues to identify specific deficits and its functional detriments, treatment options need to evolve to better target identified functional deficits. Social Cognition and Interaction Training (SCIT) was recently developed to address specific socio-cognitive deficits in an inpatient population of individuals with schizophrenia-spectrum disorders. This study applied SCIT in an outpatient SMI population as many deficits remain after individuals’ symptoms are less severe and overall functioning is more stable than during the acute inpatient phase of their rehabilitation. Specifically, this study has two objectives. First, to demonstrate that deficits in social cognition persist after the acute phase of illness has abated. Second, to demonstrate that these deficits can be ameliorated via targeted treatment such as SCIT. Data was gathered in local outpatient treatment settings serving a heterogeneous SMI population. Adviser: William D. Spaulding

Assessment of metal and trace element concentrations in the Cananeia estuary, Brazil, by neutron activation and atomic absorption techniques

Twenty six bottom sediment samples were collected from the Cananeia estuary in summer and winter of 2005. Multielemental analysis was carried out by instrumental neutron activation analysis. Total mercury was determined by cold vapor atomic absorption. As, Cr, Hg and Zn concentrations were compared to the Canadian oriented values (TEL and PEL). Sample points 4 and 9 presented higher concentration for most elements and As and Cr exceeded the TEL values. Organic matter (>10%) associated with siltic and clay sediments was observed. Climatic conditions, hydrodynamic and biogeochemical processes promote differences in seasonal concentrations of elements at some points, which contribute to special distributions.

Temperature Effect on the Two-Photon Absorption Spectrum of All-trans-beta-carotene

In this report, we investigate the influence of temperature on the two-photon absorption (2PA) spectrum of all-trans-beta-carotene using the femtosecond white-light-continuum Z-scan technique. We observed that the 2PA cross-section decreases quadratically with the temperature. Such effect was modeled using a three-energy-level diagram within the sum-over-essential states approach, assuming temperature dependencies to the transition dipole moment and refractive index of the solvent. The results show that the transition dipole moments from ground to excited state and between the excited states, which governed the two-photon matrix element, have distinct behaviors with the temperature. The first one presents a quadratic dependence, while the second exhibits a linear dependence. Such effects were attributed mainly to the trans -> cis thermal interconversion process, which decreases the effective conjugation length, contributing to diminishing the transition dipole moments and, consequently, the 2PA cross-section.

Analytic perturbation theory for bound states in the transfer matrix spectrum of weakly correlated lattice ferromagnetic spin systems

We consider general d-dimensional lattice ferromagnetic spin systems with nearest neighbor interactions in the high temperature region ('beta' << 1). Each model is characterized by a single site apriori spin distribution taken to be even. We also take the parameter 'alfa' = ('S POT.4') - 3 '(S POT.2') POT.2' > 0, i.e. in the region which we call Gaussian subjugation, where ('S POT.K') denotes the kth moment of the apriori distribution. Associated with the model is a lattice quantum field theory known to contain a particle of asymptotic mass -ln 'beta' and a bound state below the two-particle threshold. We develop a 'beta' analytic perturbation theory for the binding energy of this bound state. As a key ingredient in obtaining our result we show that the Fourier transform of the two-point function is a meromorphic function, with a simple pole, in a suitable complex spectral parameter and the coefficients of its Laurent expansion are analytic in 'beta'.

Complete Sequence of Broad-Host-Range Plasmid pRIO-5 Harboring the Extended-Spectrum-beta-Lactamase Gene bla(BES-1)

Broad-host-range plasmid pRIO-5, harboring the extended-spectrum beta-lactamase bla(BES-1) gene in Serratia marcescens, was fully sequenced. Analysis of the 12,957-bp sequence of this IncP6-type plasmid revealed that the bla(BES-1) gene was associated with two copies of the insertion sequence IS26. The promoter responsible for the bla(BES-1) expression was hybrid, made of a - 35 box located inside the inverted repeat of IS26 and a - 10 box inside a remnant of an insertion sequence.

Fractal descriptors based on Fourier spectrum applied to texture analysis

This work proposes the development and study of a novel technique lot the generation of fractal descriptors used in texture analysis. The novel descriptors are obtained from a multiscale transform applied to the Fourier technique of fractal dimension calculus. The power spectrum of the Fourier transform of the image is plotted against the frequency in a log-log scale and a multiscale transform is applied to this curve. The obtained values are taken as the fractal descriptors of the image. The validation of the proposal is performed by the use of the descriptors for the classification of a dataset of texture images whose real classes are previously known. The classification precision is compared to other fractal descriptors known in the literature. The results confirm the efficiency of the proposed method. (C) 2012 Elsevier B.V. All rights reserved.

Riemannian Submersions with Discrete Spectrum

We prove some estimates on the spectrum of the Laplacian of the total space of a Riemannian submersion in terms of the spectrum of the Laplacian of the base and the geometry of the fibers. When the fibers of the submersions are compact and minimal, we prove that the spectrum of the Laplacian of the total space is discrete if and only if the spectrum of the Laplacian of the base is discrete. When the fibers are not minimal, we prove a discreteness criterion for the total space in terms of the relative growth of the mean curvature of the fibers and the mean curvature of the geodesic spheres in the base. We discuss in particular the case of warped products.