Accretion by Isolated Neutron Stars

Accretion of interstellar material by an isolated neutron star is discussed. The point I address here is the interaction between the accretion flow and the stellar magnetosphere. I show that the interchange instabilities of the magnetospheric boundary under the conditions of interest are basically suppressed. The entry of the material into the magnetosphere is governed by diffusion. Due to this reason the persistent accretion luminosity of isolated neutron stars is limited to < 4E+26 erg/s. These objects can also appear as X-ray bursters with the burst durations of about 30 minutes and repetition time of about 1E+5 yr. This indicates that the number of the accreting isolated neutron stars which could be observed with recent and modern X-ray missions is a few orders of magnitude smaller than that previously estimated.Comment: 3 pages, to appear in Astrophysics and Space Science, in the proceedings of "Isolated Neutron Stars: from the Interior to the Surface", edited by D. Page, R. Turolla and S. Zan

Home-based exercise rehabilitation in addition to specialist heart failure nurse care: design, rationale and recruitment to the Birmingham Rehabilitation Uptake Maximisation study for patients with congestive heart failure (BRUM-CHF): a randomised controlled trial.

Background Exercise has been shown to be beneficial for selected patients with heart failure, but questions remain over its effectiveness, cost-effectiveness and uptake in a real world setting. This paper describes the design, rationale and recruitment for a randomised controlled trial that will explore the effectiveness and uptake of a predominantly home-based exercise rehabilitation programme, as well as its cost-effectiveness and patient acceptability. Methods/design Randomised controlled trial comparing specialist heart failure nurse care plus a nurse-led predominantly home-based exercise intervention against specialist heart failure nurse care alone in a multiethnic city population, served by two NHS Trusts and one primary care setting, in the United Kingdom. 169 English speaking patients with stable heart failure, defined as systolic impairment (ejection fraction ≤ 40%). with one or more hospital admissions with clinical heart failure or New York Heart Association (NYHA) II/III within previous 24-months were recruited. Main outcome measures at 1 year: Minnesota Living with Heart Failure Questionnaire, incremental shuttle walk test, death or admission with heart failure or myocardial infarction, health care utilisation and costs. Interviews with purposive samples of patients to gain qualitative information about acceptability and adherence to exercise, views about their treatment, self-management of their heart failure and reasons why some patients declined to participate. The records of 1639 patients managed by specialist heart failure services were screened, of which 997 (61%) were ineligible, due to ejection fraction>40%, current NYHA IV, no admission or NYHA II or more within the previous 2 years, or serious co-morbidities preventing physical activity. 642 patients were contacted: 289 (45%) declined to participate, 183 (39%) had an exclusion criterion and 169 (26%) agreed to randomisation. Discussion Due to safety considerations for home-exercise less than half of patients treated by specialist heart failure services were eligible for the study. Many patients had co-morbidities preventing exercise and others had concerns about undertaking an exercise programme

Direct composition profiling in III-V nanostructures by cross-sectional STM

Using cross-sectional STM we have studied the local composition in III–V nanostructures such as GaAs/InGaAs quantum wells, InGaNAs/InP quantum wells and quantum dots, and InAs/GaAs self-assembled quantum dots. We are able to determine the local composition by either simply counting the constituent atoms, measuring the local lattice constant or measuring the relaxation of the cleaved surface due to the elastic field of the buried strained nanostructures

The self-reported importance of olfaction during human mate choice

This study evaluated sex differences in the relative importance placed on olfactory cues during mate choice. To evaluate this 151 men and 289 women completed an on-line version of the Romantic Interests Survey (RIS) (Herz & Inzlict, 2002). Olfactory characteristics were declared to be extremely important during mate selection, more so than almost all other characteristics, but did not significantly differ between the sexes. There were significant differences concerning the odour source that individuals attend to, with greater preferences observed for a potential mate’s body odour as opposed to artificial fragrances they use. These findings suggest the body odour characteristics of a potential mate are perceived to be an important factor during mate choice

Aggression, empathy and sexual orientation in males

Homosexual males are reported to be less physically aggressive than heterosexual males (Ellis, Hoffman, & Burke, 1990; Gladue & Bailey, 1995). Previous aggression studies have not, however, compared all forms of direct aggression, indirect aggression and empathy among these populations. Empathy is a significant factor to consider since it both mitigates the expression of aggression (Kaukiainen, Björkqvist, Lagerspetz, Österman, Salmivalli, Rothberg, & Ahlbom, 1998) and differs between heterosexual and homosexual males (Salais & Fischer, 1995). This study therefore evaluated levels of direct and indirect aggression and empathy among homosexual (n = 91) and heterosexual (n = 91) males. Data was collected from an Internet-based sample of the two groups using self-report psychometric measures in order to reduce social desirability effects. Homosexual males reported significantly lower levels of physical aggression and higher levels of empathy but report similar levels of indirect aggression, and other forms of direct aggression, to heterosexual males

Geometrothermodynamics of five dimensional black holes in Einstein-Gauss-Bonnet-theory

We investigate the thermodynamic properties of 5D static and spherically symmetric black holes in (i) Einstein-Maxwell-Gauss-Bonnet theory, (ii) Einstein-Maxwell-Gauss-Bonnet theory with negative cosmological constant, and in (iii) Einstein-Yang-Mills-Gauss-Bonnet theory. To formulate the thermodynamics of these black holes we use the Bekenstein-Hawking entropy relation and, alternatively, a modified entropy formula which follows from the first law of thermodynamics of black holes. The results of both approaches are not equivalent. Using the formalism of geometrothermodynamics, we introduce in the manifold of equilibrium states a Legendre invariant metric for each black hole and for each thermodynamic approach, and show that the thermodynamic curvature diverges at those points where the temperature vanishes and the heat capacity diverges.Comment: New sections added, references adde

The bulk correlation length and the range of thermodynamic Casimir forces at Bose-Einstein condensation

The relation between the bulk correlation length and the decay length of thermodynamic Casimir forces is investigated microscopically in two three-dimensional systems undergoing Bose-Einstein condensation: the perfect Bose gas and the imperfect mean-field Bose gas. For each of these systems, both lengths diverge upon approaching the corresponding condensation point from the one-phase side, and are proportional to each other. We determine the proportionality factors and discuss their dependence on the boundary conditions. The values of the corresponding critical exponents for the decay length and the correlation length are the same, equal to 1/2 for the perfect gas, and 1 for the imperfect gas

Resonant transmission through an open quantum dot

We have measured the low-temperature transport properties of a quantum dot formed in a one-dimensional channel. In zero magnetic field this device shows quantized ballistic conductance plateaus with resonant tunneling peaks in each transition region between plateaus. Studies of this structure as a function of applied perpendicular magnetic field and source-drain bias indicate that resonant structure deriving from tightly bound states is split by Coulomb charging at zero magnetic field.Comment: To be published in Phys. Rev. B (1997). 8 LaTex pages with 5 figure

Probabilistic frames: An overview

Finite frames can be viewed as mass points distributed in $N$-dimensional Euclidean space. As such they form a subclass of a larger and rich class of probability measures that we call probabilistic frames. We derive the basic properties of probabilistic frames, and we characterize one of their subclasses in terms of minimizers of some appropriate potential function. In addition, we survey a range of areas where probabilistic frames, albeit, under different names, appear. These areas include directional statistics, the geometry of convex bodies, and the theory of t-designs