B-field Determination from Magnetoacoustic Oscillations in kHz QPO Neutron Star Binaries: Theory and Observations

We present a method for determining the B-field around neutron stars based on observed kHz and viscous QPO frequencies used in combination with the best-fit optical depth and temperature of a Comptonization model. In the framework of the transition layer QPO model, we analyze magnetoacoustic wave formation in the layer between a neutron star surface and the inner edge of a Keplerian disk. We derive formulas for the magnetoacoustic wave frequencies for different regimes of radial transition layer oscillations. We demonstrate that our model can use the QPO as a new kind of probe to determine the magnetic field strengths for 4U 1728-42, GX 340+0, and Sco X-1 in the zone where the QPOs occur. Observations indicate that the dependence of the viscous frequency on the Keplerian frequency is closely related to the inferred dependence of the magnetoacoustic wave frequency on the Keplerian frequency for a dipole magnetic field. The magnetoacoustic wave dependence is based on a single parameter, the magnetic moment of the star as estimated from the field strength in the transition layer. The best-fit magnetic moment parameter is about (0.5-1)x 10^{25} G cm^3 for all studied sources. From observational data, the magnetic fields within distances less 20 km from neutron star for all three sources are strongly constrained to be dipole fields with the strengths 10^{7-8} G on the neutron star surface.Comment: 10 pages, 1 figure, accepted for the Astrophysical Journal Letter

Using molecular mechanics to predict bulk material properties of fibronectin fibers

The structural proteins of the extracellular matrix (ECM) form fibers with finely tuned mechanical properties matched to the time scales of cell traction forces. Several proteins such as fibronectin (Fn) and fibrin undergo molecular conformational changes that extend the proteins and are believed to be a major contributor to the extensibility of bulk fibers. The dynamics of these conformational changes have been thoroughly explored since the advent of single molecule force spectroscopy and molecular dynamics simulations but remarkably, these data have not been rigorously applied to the understanding of the time dependent mechanics of bulk ECM fibers. Using measurements of protein density within fibers, we have examined the influence of dynamic molecular conformational changes and the intermolecular arrangement of Fn within fibers on the bulk mechanical properties of Fn fibers. Fibers were simulated as molecular strands with architectures that promote either equal or disparate molecular loading under conditions of constant extension rate. Measurements of protein concentration within micron scale fibers using deep ultraviolet transmission microscopy allowed the simulations to be scaled appropriately for comparison to in vitro measurements of fiber mechanics as well as providing estimates of fiber porosity and water content, suggesting Fn fibers are approximately 75% solute. Comparing the properties predicted by single molecule measurements to in vitro measurements of Fn fibers showed that domain unfolding is sufficient to predict the high extensibility and nonlinear stiffness of Fn fibers with surprising accuracy, with disparately loaded fibers providing the best fit to experiment. This work shows the promise of this microstructural modeling approach for understanding Fn fiber properties, which is generally applicable to other ECM fibers, and could be further expanded to tissue scale by incorporating these simulated fibers into three dimensional network models

An Exploratory Study of Speech-Language Pathologists\u27 Perceptions of Multicultural Counseling in Communication Sciences and Disorders

Speech-language pathologists’ (SLPs) perceptions of multicultural counseling vary according to their academic (teaching and learning), educational, supervisory, supervisee, and clinical experiences. With the increase of culturally and linguistically diverse populations, the implementation of multicultural counseling in communication sciences and disorders (CSD) is essential to providing efficacious assessments and interventions. The current research reports data from a recent survey that queried SLPs’ perceptions of multicultural counseling in CSD. Results from the survey reveal that SLPs\u27 perceptions of MC vary according to their experiences (e.g., educational, supervisory, clinical)

Laser-controlled fluorescence in two-level systems

The ability to modify the character of fluorescent emission by a laser-controlled, optically nonlinear process has recently been shown theoretically feasible, and several possible applications have already been identified. In operation, a pulse of off-resonant probe laser beam, of sufficient intensity, is applied to a system exhibiting fluorescence, during the interval of excited- state decay following the initial excitation. The result is a rate of decay that can be controllably modified, the associated changes in fluorescence behavior affording new, chemically specific information. In this paper, a two-level emission model is employed in the further analysis of this all-optical process; the results should prove especially relevant to the analysis and imaging of physical systems employing fluorescent markers, these ranging from quantum dots to green fluorescence protein. Expressions are presented for the laser-controlled fluorescence anisotropy exhibited by samples in which the fluorophores are randomly oriented. It is also shown that, in systems with suitably configured electronic levels and symmetry properties, fluorescence emission can be produced from energy levels that would normally decay nonradiatively. © 2010 American Chemical Society

Technical Reference: Using Lightning Location in the Wildland Fire Assessment System

Location of the ground position of lightning discharges has been possible for several years. A technique for using ignition probability calculations together with lightning location data results in maps that are useful to fire managers in making decisions on timescales from historical to real-time. These maps, part of the Wildland Fire Assessment System, will aid fire managers in assessing the potential that lightning will result in reportable fires. The maps are generated using ignition probability based on duff depth, fuel moisture, and fuel type. To match fire potential classes, ignition probabilities are classified into ignition potential classes of low. medium, high, very high, and extreme. Possible benefits are savings in time, fire suppression costs, and perhaps even lives

Raman scattering mediated by neighboring molecules

Raman scattering is most commonly associated with a change in vibrational state within individual molecules, the corresponding frequency shift in the scattered light affording a key way of identifying material structures. In theories where both matter and light are treated quantum mechanically, the fundamental scattering process is represented as the concurrent annihilation of a photon from one radiation mode and creation of another in a different mode. Developing this quantum electrodynamical formulation, the focus of the present work is on the spectroscopic consequences of electrodynamic coupling between neighboring molecules or other kinds of optical center. To encompass these nanoscale interactions, through which the molecular states evolve under the dual influence of the input light and local fields, this work identifies and determines two major mechanisms for each of which different selection rules apply. The constituent optical centers are considered to be chemically different and held in a fixed orientation with respect to each other, either as two components of a larger molecule or a molecular assembly that can undergo free rotation in a fluid medium or as parts of a larger, solid material. The two centers are considered to be separated beyond wavefunction overlap but close enough together to fall within an optical near-field limit, which leads to high inverse power dependences on their local separation. In this investigation, individual centers undergo a Stokes transition, whilst each neighbor of a different species remains in its original electronic and vibrational state. Analogous principles are applicable for the anti-Stokes case. The analysis concludes by considering the experimental consequences of applying this spectroscopic interpretation to fluid media; explicitly, the selection rules and the impact of pressure on the radiant intensity of this process

Foraging ecology of a generalist predator the female New Zealand fur seal

Copyright © 2002 Inter-Research.Abstract: This study examined how diet, foraging location and diving behaviour of female New Zealand fur seals Arctocephalus forsteri at Otago Peninsula, New Zealand (45°52¹S, 170°44¹E), varied in relation to prey abundance among seasons in 1994 and 1995. Time-depth recorders measured the diving behaviour of 24 lactating female fur seals, during summer, autumn or winter of 1994 and summer and autumn of 1995. Foraging locations were obtained by deploying satellite transmitters in summer, autumn and winter of 1994 only. Estimated biomass of prey items was determined from 690 scats and 166 regurgitates collected over summer, autumn and winter of both years, and compared with abundance data from research trawls in the same area. Foraging trip duration increased during the cooler seasons. Female fur seals showed a clear bout structure in dive behaviour, with the relative proportion of 3 main bout types (Long, Shallow, Deep) varying with season. Time between bouts (IBI) and bout duration varied with season, suggesting that prey distribution and prey encounter rate also varied. Linear discriminant analysis of the dive and foraging trip characteristics of individual females demonstrated clear seasonal differences. Females foraged on or near the continental slope in summer and farther offshore in autumn. Satellite telemetry locations and diet suggest principally inshore foraging during winter. Fur seals ate predominantly arrow squid Nototodarus sloanii during summer and autumn of both years, although fish, particularly myctophids, were persistent in the diet. Arrow squid were less common in winter when diet was more varied, and an inshore, benthic fish, ahuru Auchenoceros punctatus was dominant. There was no relationship between the annual changes in abundance of major prey species as measured by research trawls and their occurrence in seal diet. Overall, changes in dive behaviour may reflect changes in prey selection as prey abundance and availability change among seasons.Robert G. Harcourt, Corey J. A. Bradshaw, Kate Dickson, Lloyd S. Davi

Laser-modified one- and two-photon absorption:Expanding the scope of optical nonlinearity

It is shown that conventional one-photon and two-photon absorption processes can be made subject to nonlinear optical control, in each case significantly modifying the efficiency of absorption, through the effect of a secondary, off-resonant stimulus laser beam. The mechanistic origin of these laser-modified absorption processes, in which the stimulus beam emerges unchanged, is traced to higher-order terms in standard perturbation treatments. These normally insignificant terms become unusually prominent when the secondary optical stimulus is moderately intense. Employing a quantum formulation, the effects of the stimulus beam on one-photon and two-photon absorption are analyzed, and calculations are performed to determine the degree of absorption enhancement, and the form of spectral manifestation, under various laser intensities. The implications of differences in selection rules are also considered and exemplified, leading to the identification of dark states that can be populated as a result of laser-modified absorption. Attention is also drawn to the possibility of quantum nondemolition measurements, based on such a form of optical nonlinearity

Children’s Subjective Well-being in Rich Countries

This paper is based on background research we undertook for UNICEF Innocenti Report Card 11 on child well-being in rich countries. It develops a new domain index of subjective well-being based on seven indicators drawn from the Health Behaviour of School Aged Children (HBSC) survey 2009/10, which includes life satisfaction, relationships with family and friends, well-being at school, and subjective health. It explores the associations between the indicators, components and the overall domain. Changes in subjective well-being between HBSC 2001/2 and 2009/10 are analysed. It then explores the relationships between subjective well-being and objective domains: material, health, education, behaviour and housing and environment. At a macro level subjective well-being is associated with all those domains. It concludes that subjective well-being should be included in comparative studies of well-being but not necessarily as just another domain. It is a related but different order measure

Interparticle interactions:Energy potentials, energy transfer, and nanoscale mechanical motion in response to optical radiation

In the interactions between particles of material with slightly different electronic levels, unusually large shifts in the pair potential can result from photoexcitation, and on subsequent electronic excitation transfer. To elicit these phenomena, it is necessary to understand the fundamental differences between a variety of optical properties deriving from dispersion interactions, and processes such as resonance energy transfer that occur under laser irradiance. This helps dispel some confusion in the recent literature. By developing and interpreting the theory at a deeper level, one can anticipate that in suitable systems, light absorption and energy transfer will be accompanied by significant displacements in interparticle separation, leading to nanoscale mechanical motion