Discrete-step evaporation of an atomic beam

We present a theoretical analysis of the evaporative cooling of a magnetically guided atomic beam by means of discrete radio-frequency antennas. First we derive the changes in flux and temperature, as well as in collision rate and phase-space density, for a single evaporation step. Next we show how the occurrence of collisions during the propagation between two successive antennas can be probed. Finally, we discuss the optimization of the evaporation ramp with several antennas to reach quantum degeneracy. We estimate the number of antennas required to increase the phase-space density by several orders of magnitude. We find that at least 30 antennas are needed to gain a factor $10^8$ in phase-space density.Comment: Submitted to Eur. Phys. J.

To Survive And To Thrive: Integrating Services For The Homeless Mentally Ill

An intervention research project with homeless, chronically mentally ill persons demonstrated that linking rehabilitation services, such as employment skills and psycho-social stabilization, with survival services promotes success in serving this population. The project confirmed the central role of case managers in promoting engagement with mental health services and re-integration into stable community living

Ozonolysis of surface-adsorbed methoxyphenols: kinetics of aromatic ring cleavage vs. alkene side-chain oxidation

Lignin pyrolysis products, which include a variety of substituted methoxyphenols, constitute a major component of organics released by biomass combustion, and may play a central role in the formation of atmospheric brown carbon. Understanding the atmospheric fate of these compounds upon exposure to trace gases is therefore critical to predicting the chemical and physical properties of biomass burning aerosol. We used diffuse reflectance infrared spectroscopy to monitor the heterogeneous ozonolysis of 4-propylguaiacol, eugenol, and isoeugenol adsorbed on NaCl and α-Al₂O₃ substrates. Adsorption of gaseous methoxyphenols onto these substrates produced near-monolayer surface concentrations of 3 × 10¹⁸ molecules m⁻². The subsequent dark heterogeneous ozonolysis of adsorbed 4-propylguaiacol cleaved the aromatic ring between the methoxy and phenol groups with the product conclusively identified by GC-MS and ¹H-NMR. Kinetic analysis of eugenol and isoeugenol dark ozonolysis also suggested the formation of ring-cleaved products, although ozonolysis of the unsaturated substituent groups forming carboxylic acids and aldehydes was an order of magnitude faster. Average uptake coefficients for NaCl-adsorbed methoxyphenols were γ = 2.3 (± 0.8) × 10^−7 and 2 (± 1) × 10^−6 for ozonolysis of the aromatic ring and the unsaturated side chain, respectively, and reactions on α-Al₂O₃ were approximately two times slower. UV–visible radiation (λ > 300 nm) enhanced eugenol ozonolysis of the aromatic ring by a factor of 4(± 1) but had no effect on ozonolysis of the alkene side chain

Prevalence and Risk Factors for Poor Mental Health and Suicidal Ideation in the Nigerian Construction Industry

Employees' mental health and well-being are a growing concern as countries grapple with heightened mental ill-health and suicide rates, with the construction industry ranking in the top five. Drawing from the context of a developing country, particularly Nigeria, data were collected using mixed methods (i.e., survey and postsurvey interview). The study investigated mental health among 382 construction personnel. The Patient Health Questionnaire (PHQ-9) and Generalized Anxiety Disorder (GAD-2) scales were employed in assessing mental health. The data collected were analyzed using descriptive statistics and logistic regression. The prevalence rates of depression, anxiety, and suicidal ideation were 55.1%, 16%, 9.8% among supervisors, 72%, 36.9%, and 15.3%, respectively, among tradesmen. Univariate logistic regression revealed that years of experience and organizational structure influence mental health. Multiple logistic regression showed that risk factors for mental ill-health include nature of work, little relationship with colleagues, job insecurity, occupational injury, low income, and unsatisfactory living conditions. The findings from this study will assist in intervention building and policy-making within the construction industry of Nigeria and globally

Entropy on Spin Factors

Recently it has been demonstrated that the Shannon entropy or the von Neuman entropy are the only entropy functions that generate a local Bregman divergences as long as the state space has rank 3 or higher. In this paper we will study the properties of Bregman divergences for convex bodies of rank 2. The two most important convex bodies of rank 2 can be identified with the bit and the qubit. We demonstrate that if a convex body of rank 2 has a Bregman divergence that satisfies sufficiency then the convex body is spectral and if the Bregman divergence is monotone then the convex body has the shape of a ball. A ball can be represented as the state space of a spin factor, which is the most simple type of Jordan algebra. We also study the existence of recovery maps for Bregman divergences on spin factors. In general the convex bodies of rank 2 appear as faces of state spaces of higher rank. Therefore our results give strong restrictions on which convex bodies could be the state space of a physical system with a well-behaved entropy function.Comment: 30 pages, 6 figure

Deprivation is associated with anxiety and stress. A population-based longitudinal household survey among Chinese adults in Hong Kong

BACKGROUND: Mental illness is a major disease burden in the world and disproportionately affects the socially disadvantaged, but studies on the longitudinal association of poverty with anxiety and stress are rare, especially in Asia. Using data from Hong Kong, we aimed to (1) assess the cross-sectional association of poverty with anxiety and stress at baseline, and (2) to examine whether baseline poverty and change in poverty status over time are associated with a subsequent change in anxiety and stress. METHODS: Data were obtained from two waves of a territory-wide longitudinal survey in Hong Kong, with sample sizes of n=1970 and n=1224 for baseline and follow-up, respectively. Poverty was measured with a Deprivation Index and income-poverty. Anxiety and stress symptoms were assessed using Chinese Depression, Anxiety and Stress Scale-21 Items. We conducted cross-sectional and longitudinal analyses on the association of poverty with anxiety and stress. OUTCOMES: Deprivation, but not income-poverty, was significantly associated with both outcomes at baseline. Increased deprivation over time was associated with greater score and increased risk of anxiety and stress. Persistent deprivation over time was associated with greater anxiety and stress, and increased risk of incident anxiety. INTERPRETATION: Deprivation could have significant independent effects on anxiety and stress, even after adjusting for the effects of income-poverty. Greater attention should be paid to deprivation in policymaking to tackle the inequalities of mental health problems, especially since stress and anxiety are precursors to more severe forms of mental illness and other comorbidities