Testing Explanations of the B→ϕK∗B\to\phi K^* Polarization Puzzle

$B\to\phi K^*$ (\btos) is three separate decays, one for each polarization of the final-state vector mesons (one longitudinal, two transverse). It is observed that the fraction of transverse decays, \fT, and the fraction of longitudinal decays, \fL, are roughly equal: \fTfL \simeq 1, in opposition to the naive expectation that \fT \ll \fL. If one requires a single explanation of all polarization puzzles, two possibilities remain within the standard model: penguin annihilation and rescattering. In this paper we examine the predictions of these two explanations for \fTfL in \btod decays. In $B \to \rho\rho$ decays, only \bd \to \rho^0\rho^0 can possibly exhibit a large \fTfL. In B decays related by U-spin, we find two promising possibilities: (i) $B^+ \to K^{*0} \rho^+$ (\btos) and B^+ \to \Kbar^{*0} K^{*+} (\btod) and (ii) \bs \to K^{*0} \Kbar^{*0} (\btos) and \bd \to \Kbar^{*0} K^{*0} (\btod). The measurement of \fTfL in these pairs of decays will allow us to test penguin annihilation and rescattering. Finally, it is possible to distinguish penguin annihilation from rescattering by performing a time-dependent angular analysis of \bd \to \Kbar^{*0} K^{*0}.Comment: 15 pages, 2 figures. Added reference and PACS numbers. To appear in PR

Marriage as a Rat Race: Noisy Pre-Marital Investments with Assortative Matching

We study the incentive to invest to improve marriage prospects, in a frictionless marriage market with non-transferable utility. Stochastic returns to investment eliminate the multiplicity of equilibria in models with deterministic returns, and a unique equilibrium exists under reasonable conditions. Equilibrium investment is efficient when the sexes are symmetric. However, when there is any asymmetry, including an unbalanced sex ratio, investments are generically excessive. For example, if there is an excess of boys, then there is parental over-investment in boys and under-investment in girls, and total investment will be excessive.marriage, ex ante investments, gender differences, assortative matching tournament, sex ratio

Nonclassical rotational behavior at the vicinity of the lamda point

The rotational property of a quantum liquid at the vicinity of the lambda point is examined. In a liquid helium 4 just above the lambda point, under the strong influence of Bose statistics, the coherent many-body wave function grows to an intermediate size between a macroscopic and a microscopic one, which is of a different nature from the thermal fluctuations. It must reflect in the rotational properties such as the moment of inertia. Beginning with the bosons without the condensate, we make a perturbation calculation of its susceptibility with respect to the repulsive interaction, and examine how, with decreasing temperature, the growth of the coherent wave function gradually changes the rotational behavior of a liquid:The moment of inertia slightly decreases just above the lambda point. This means that at the vicinity of the lambda point, the mechanical superfluid density does not always agree with the thermodynamical one.We compare the result to the experiment by Hess and Fairbank. A new interpretation of the shear viscosity just above the lambda point is given from this viewpoint.Comment: 12pages, 5figure

CMB Fluctuation Amplitude from Dark Energy Partitions

It is assumed that the dark energy observed today is frozen as a result of a phase transition involving the source of that energy. Postulating that the dark energy de-coherence which results from this phase transition drives statistical variations in the energy density specifies a class of cosmological models in which the cosmic microwave background (CMB) fluctuation amplitude at last scattering is approximately $10^{-5}$.Comment: 7 Pages, Poster presented at Texas@Stanford conference, Dec. 2004, minor clarification

Study of Polarization in B -> VT Decays

In this paper, we examine B -> VT decays (V is a vector and T is a tensor meson), whose final-state particles can have transverse or longitudinal polarization. Measurements have been made of B -> \phi K_2^*, and it is found that fT/fL is small, where fT (fL) is the fraction of transverse (longitudinal) decays. We find that the standard model (SM) naively predicts that fT/fL << 1. The two extensions of the naive SM which have been proposed to explain the large fT/fL in B -> \phi K^* -- penguin annihilation and rescattering -- make no firm predictions for the polarization in B -> \phi K_2^*. The two new-physics scenarios, which explain the data in B -> \pi K and the \phi (\rho) K^* polarization measurements, can reproduce the fT/fL data in B -> \phi K_2^* only if the B -> T form factors obey a certain hierarchy. Finally, we present the general angular analysis which can be used to get helicity information using two- and three-body decays.Comment: 15 pages, latex, 3 figures (enclosed), several changes made, conclusions unchanged, publication info adde

Striatal dopamine D1-type receptor availability: no difference from control but association with cortical thickness in methamphetamine users.

Chronic methamphetamine use poses potentially devastating consequences for directly affected individuals and for society. Lower dopamine D2-type receptor availability has been observed in striata of methamphetamine users as compared with controls, but an analogous comparison of D1-type receptors has been conducted only on post-mortem material, with no differences in methamphetamine users from controls in the caudate nucleus and putamen and higher D1-receptor density in the nucleus accumbens. Released from neurons when methamphetamine is self-administered, dopamine binds to both D1- and D2-type receptors in the striatum, with downstream effects on cortical activity. Thus, both receptor subtypes may contribute to methamphetamine-induced alterations in cortical morphology and behavior. In this study, 21 methamphetamine-dependent subjects and 23 healthy controls participated in positron emission tomography and structural magnetic resonance imaging for assessment of striatal D1- and D2-type receptor availability and cortical gray-matter thickness, respectively. Although D2-type receptor availability (BPnd) was lower in the methamphetamine group, as shown previously, the groups did not differ in D1-type BPnd. In the methamphetamine group, mean cortical gray-matter thickness was negatively associated with cumulative methamphetamine use and craving for the drug. Striatal D1-type but not D2-type BPnd was negatively associated with global mean cortical gray-matter thickness in the methamphetamine group, but no association was found between gray-matter thickness and BPnd for either dopamine receptor subtype in the control group. These results suggest a role of striatal D1-type receptors in cortical adaptation to chronic methamphetamine use

Disorder Effects in Fluctuating One-Dimensional Interacting Systems

The zero temperature localization of interacting electrons coupled to a two-dimensional quenched random potential, and constrained to move on a fluctuating one-dimensional string embedded in the disordered plane, is studied using a perturbative renormalization group approach. In the reference frame of the electrons the impurities are dynamical and their localizing effect is expected to decrease. We consider several models for the string dynamics and find that while the extent of the delocalized regime indeed grows with the degree of string fluctuations, the critical interaction strength, which determines the localization-delocalization transition for infinitesimal disorder,does not change unless the fluctuations are softer than those of a simple elastic string.Comment: 15 page

Coexistence of Non-Conventional Condensates in Two-Level Bose Atom System

In the framework of the Bogolyubov approximation and using the Bogolyubov inequalities we give a simple proof of the coexistence of two non-conventional Bose-Einstein condensates in the case of some superstable Bose system whose atoms have an internal two-level structure and their energy operators in the second quantized form depend on the number operators only.Comment: 17 page

Shortfall in stroke care: A study of ischaemic stroke care practices in a South African metropole

Background. In recent years there have been significant advances in the management of stroke. In particular, reperfusion therapies have been shown to confer significant benefit, with the possibility of reversing ischaemic stroke or reducing disability when administered to suitable patients. However, these therapies also carry significant risk, including death. The South African (SA) and other international guidelines for stroke care provide recommendations to optimise benefit and reduce risk of these novel treatments. Failure to adhere to recommended guidelines can lead to increased preventable morbidity and mortality in such patients.Objectives. To describe the acute and post-acute ischaemic stroke services offered to patients in level 1, 2 and 3 hospitals in the Cape Metro Health District, determine levels of adherence to the SA stroke guideline, and identify barriers to optimal stroke patient care.Methods. This study in five level 1, one level 2 and two level 3 public hospitals involved semi-structured interviewer-administered questionnaires and reviews of ischaemic stroke patient discharge summaries, hospital staffing, stroke protocols, diagnostic investigations available and stroke education for patients and their caregivers. The findings were then compared with recommendations in the national guideline.Results. Twenty-eight participants (18 doctors, 10 nurses) from the general medical wards, stroke units and emergency units of eight hospitals were invited to participate in interviews. Most level 1 and 2 hospitals experienced difficulties transferring patients to higher levels of care. There was also limited access to stroke management protocols, inadequate stroke education among health professionals, pre- and in-hospital delays in patients receiving medical attention, and limited access to diagnostic investigations. As only a total of 12 stroke unit beds were available at the two level 3 hospitals, the majority of ischaemic stroke patients were admitted to the general medical wards of level 1, 2 and 3 hospitals. The level of care at all these facilities was not homogeneous.Conclusions. The two stroke units at the level 3 hospitals adhered most closely to the recommended SA stroke guideline. Elsewhere, ischaemic stroke care varied widely across general medical wards at all hospital levels. Adherence to the guideline was influenced by factors such as limited access to diagnostic investigations, patient delays in receiving medical attention, and shortages of staff. Monitoring systems for continuous evaluation of the quality of acute and post-acute stroke services are needed. The shortfall in compliance with recommended stroke treatment guidelines could lead to worse outcomes and exposure to litigation

Superadiabatic transitions in quantum molecular dynamics

We study the dynamics of a molecule’s nuclear wave function near an avoided crossing of two electronic energy levels for one nuclear degree of freedom. We derive the general form of the Schrödinger equation in the nth superadiabatic representation for all n є N. Using these results, we obtain closed formulas for the time development of the component of the wave function in an initially unoccupied energy subspace when a wave packet travels through the transition region. In the optimal superadiabatic representation, which we define, this component builds up monotonically. Finally, we give an explicit formula for the transition wave function away from the avoided crossing, which is in excellent agreement with high-precision numerical calculations