Tailored Fano resonance and localized electromagnetic field enhancement in Ag gratings

Metallic gratings can support Fano resonances when illuminated with EM radiation, and their characteristic reflectivity versus incident angle lineshape can be greatly affected by the surrounding dielectric environment and the grating geometry. By using conformal oblique incidence thin film deposition onto an optical grating substrate, it is possible to increase the grating amplitude due to shadowing effects, thereby enabling tailoring of the damping processes and electromagnetic field couplings of the Fano resonances, hence optimizing the associated localized electric field intensity. To investigate these effects we compare the optical reflectivity under resonance excitation in samples prepared by oblique angle deposition (OAD) and under normal deposition (ND) onto the same patterned surfaces. We observe that by applying OAD method, the sample exhibits a deeper and narrower reflectivity dip at resonance than that obtained under ND. This can be explained in terms of a lower damping of Fano resonance on obliquely deposited sample and leads to a stronger localized electric field. This approach opens a fabrication path for applications where tailoring the electromagnetic field induced by Fano resonance can improve the figure of merit of specific device characteristics, e.g. quantum efficiency (QE) in grating-based metallic photocathodes

Adolescent experiences of HIV and sexual health communication with parents and caregivers in Soweto, South Africa

Communication about sexual health between parents and adolescents has been shown to have a protective influence on behaviours that reduce the risk of HIV transmission. This study explored experiences of HIV and sexual health (HSH) communication between parents and/or caregivers and adolescents in an urban HIV-endemic community in Southern Africa. Adolescents (aged 14–19 years) were recruited from the Kganya Motsha Adolescent Centre and the Kliptown community between June and August 2009. Qualitative data were collected through focus group discussions (n = 10 adolescents) and semi-structured interviews (n = 31 adolescents). In total, 41 adolescents (56% female, 44% male, mean age = 17.2) participated in the study. Adolescent participants identified emotional, physical and sociocultural barriers to initiating HSH communication with parents and caregivers including fear of verbal warnings, threats and physical assault. Adolescents also expressed a desire for mentorship around HSH communication beyond abstinence and peer-based information. Public health interventions need to support adolescents’ access to bi-directional HSH information from adult mentors that address the lived realities of adolescents beyond expectations of abstinence.Keywords: adolescent, parent–adolescent communication, qualitative, sexual health, HIV prevention, South Afric

A Super-Solar Metallicity for the Progenitor of Kepler's Supernova

We have performed deep X-ray observations of the remnant of Kepler's supernova (SN 1604) as a Key Project of the Suzaku Observatory. Our main goal is to detect secondary Fe-peak elements in the SN ejecta to gain insights into the Type Ia supernova explosion mechanism and the nature of the progenitor. Here we report our initial results. We made a conclusive detection of X-ray emission lines from highly ionized Mn, Cr, and Ni as well as Fe. The observed Mn-to-Cr line flux ratio is ~0.60, ~30% larger than that measured in Tycho's remnant. We estimate a Mn-to-Cr mass ratio of ~0.77, which is strongly suggestive of a large neutron excess in the progenitor star before the onset of the thermonuclear runaway. The observed Ni-to-Fe line flux ratio (~0.03) corresponds to a mass ratio of ~0.06, which is generally consistent with the products of explosive Si-burning regime in Type Ia explosion models, and rules out contamination from the products of neutron-rich nuclear statistical equilibrium in the shocked ejecta. Together with the previously suggested luminous nature of the explosion, these mass ratios provide strong evidence for a super-solar metallicity in the SN progenitor (~3 Z_sun). Kepler's supernova was likely the thermonuclear explosion of a white dwarf formed in the recent past that must have exploded through a relatively prompt channel.Comment: Total 12 pages including 2 tables and 2 color figures. Accepted by ApJ

Dielectric study of electrolyzed rubber

Rubber was produced by placing rubber latex between two electrodes between which an external voltage was maintained. The thickness of the rubber deposited on the anode was measured as a function of time of electrolysis, voltage applied across the electrodes and distance between the electrodes. Based on the observed dielectric responses of rubber obtained through the electrolysis process, an electrical model of conductance and complex capacitance elements linked in parallel is proposed, indicating the additive nature of the individual responses in the system. Electrical representation of rubber obtained by simple drying however showed two different models. Natural rubber was found to have all the elements connected in parallel while that of vulcanized rubber was found to have a series connection of a pair of parallel connected conductance and capacitance elements

Reproductive Decision-Making and Periconception Practices Among HIV-Positive Men and Women Attending HIV Services in Durban, South Africa

Understanding reproductive decisions and periconception behavior among HIV-discordant couples is important for designing risk reduction interventions for couples who choose to conceive. In-depth interviews were conducted to explore reproductive decision-making and periconception practices among HIV-positive women with recent pregnancy (n = 30), and HIV-positive men (n = 20), all reporting partners of negative or unknown HIV-status, and attending HIV services in Durban, South Africa. Transcripts were coded for categories and emergent themes. Participants expressed strong reasons for having children, but rarely knew how to reduce periconception HIV transmission. Pregnancy planning occurred on a spectrum ranging from explicitly intended to explicitly unintended, with many falling in between the two extremes. Male fertility desire and misunderstanding serodiscordance contributed to HIV risk behavior. Participants expressed openness to healthcare worker advice for safer conception and modified risk behavior post-conception, suggesting the feasibility of safer conception interventions which may target both men and women and include serodiscordance counseling and promotion of contraception

The prediction of fatigue using speech as a biosignal

Automatic systems for estimating operator fatigue have application in safety-critical environments. We develop and evaluate a system to detect fatigue from speech recordings collected from speakers kept awake over a 60-hour period. A binary classification system (fatigued/not-fatigued) based on time spent awake showed good discrimination, with 80 % unweighted accuracy using raw features, and 90 % with speaker-normalized features. We describe the data collection, feature analysis, machine learning and cross-validation used in the study. Results are promising for real-world applications in domains such as aerospace, transportation and mining where operators are in regular verbal communication as part of their normal working activities

Вплив харчової добавки "магнетофуд" на структурно-механічні властивості формового желейного мармеладу з різними структуроутворювачами

Development of resource- and energy-saving technologies for the production of high-quality jelly and pastille products with an extended shelf life is one of the most urgent challenges of the modern confectionery industry. It is proposed to use the "Magnetofood" mineral food supplement, which holds a high functional and technological potential and may independently form the structural and mechanical properties of jelly pastes, and also affect the gelling agents, entering into chemical and electrostatic interactions therewith. Therefore, the "Magnetofood" food supplement may influence several technological properties in the food jelly system at once: acting as a stabilizer, a thickener, a gelling agent, while improving the quality, consumer properties and extending the shelf life of molded fruit jelly products. The aim of the study is to improve the structural and mechanical properties of molded fruit jelly products by introducing the "Magnetofood" food supplement. Standard and generally accepted methods were used in the course of structural and mechanical studies (viscosity and thixotropic characteristics on the Reotest-2 rotation viscometer, strength characteristics on the AR-4/1 penetrometers). It has been established that the introduction of the "Magnetofood" food supplement into jelly pastes in the amount of 0.15 % of the total weight of raw material improves the consistency, structure, strength and form: the degree of structuring and viscosity of the jelly pastes increases over the entire shear stress range (1.5-40 s⁻¹) 2.9 times for pastes on agar and 1.85 times for pastes on pectin; the temperature effect on the effective viscosity of jelly pastes is slowed down by (50-75) Pa · s on average, destruction processes are also slowed down 1.1 times, and the recovery processes of the jelly structure after the mechanical effect ceases are accelerated by 3.8%, increasing its thixotropic ability by 7.5% in jelly pastes on agar and by 6.0% in jelly pastes on pectin; jelly strength on agar increases by (10-12)%, and by (7-9) % on pectin; the speed of structurization of jelly pastes on agar increases by a factor of 1.3-1.7, and by a factor of 1.1-1.6 on pectin.Однією з актуальних проблем сучасної кондитерської промисловості є розробка ресурсо- і енергозберігаючих технологій виробництва високоякісних мармеладо-пастильних виробів зі збільшеним терміном придатності. Пропонується використання мінеральної харчової добавки "Магнетофуд", яка володіє високим функціонально-технологічним потенціалом і може як самостійно формувати структурно-механічні властивості желейних мас, так і впливати на гелеутворювач, вступаючи з ним в хімічні і електростатичні взаємодії. Тому, харчова добавка "Магнетофуд" може впливати відразу на кілька технологічних властивостей в харчовій желейної системі: бути стабілізатором, загусником, драглеутворювачем, при цьому покращуючи якість, споживчі властивості і продовжуючи терміни зберігання формового желейного мармеладу. Метою дослідження є покращення структурно-механічних властивостей формового желейного мармеладу шляхом введення харчової добавки "Магнетофуд". Під час проведення структурно-механічних (в’язкостних і тиксотропних характеристик на ротаційному віскозиметрі Реотест-2, міцності на пенетрометри АР-4/1) досліджень були використані загальноприйняті та стандартні методики

Contraceptive Use and Method Preference among Women in Soweto, South Africa: The Influence of Expanding Access to HIV Care and Treatment Services

Objective: Preventing unintended pregnancy among HIV-positive women constitutes a critical and cost-effective approach to primary prevention of mother-to-child transmission of HIV and is a global public health priority for addressing the desperate state of maternal and child health in HIV hyper-endemic settings. We sought to investigate whether the prevalence of contraceptive use and method preferences varied by HIV status and receipt of highly active antiretroviral therapy (HAART) among women in Soweto, South Africa. Methods: We used survey data from 563 sexually active, non-pregnant women (18–44 years) recruited from the Perinatal HIV Research Unit in Soweto (May–December, 2007); 171 women were HIV-positive and receiving HAART (median duration of use = 31 months; IQR = 28, 33), 178 were HIV-positive and HAART-naïve, and 214 were HIV-negative. Medical record review was conducted to confirm HIV status and clinical variables. Logistic regression models estimated adjusted associations between HIV status, receipt of HAART, and contraceptive use. Results: Overall, 78 % of women reported using contraception, with significant variation by HIV status: 86 % of HAART users, 82 % of HAART-naïve women, and 69 % of HIV-negative women (p,0.0001). In adjusted models, compared with HIVnegativ

A Genome-Wide Association Study Provides New Evidence That CACNA1C Gene is Associated With Diabetic Cataract

PURPOSE: Diabetic cataract is one of the major eye complications of diabetes. It was reported that cataract occurs two to five times more frequently in patients with diabetes compared with those with no diabetes. The purpose of this study was to identify genetic contributors of diabetic cataract based on a genome-wide association approach using a well-defined Scottish diabetic cohort. METHODS: We adapted linked e-health records to define diabetic cataract. A diabetic cataract case in this study was defined as a type 2 diabetic patient who has ever been recorded in the linked e-health records to have cataracts in both eyes or who had previous cataract extraction surgeries in at least one eye. A control in this study was defined as a type 2 diabetic individual who has never been diagnosed as cataract in the linked e-health records and had no history of cataract surgeries. A standard genome-wide association approach was applied. RESULTS: Overall, we have 2341 diabetic cataract cases and 2878 controls in the genetics of diabetes audit and research in Tayside Scotland (GoDARTS) dataset. We found that the P value of rs2283290 in the CACNA1C gene was 8.81 × 10(−10), which has reached genome-wide significance. We also identified that the blood calcium level was statistically different between diabetic cataract cases and controls. CONCLUSIONS: We identified supporting evidence that CACNA1C gene is associated with diabetic cataract. The role of calcium in the cataractogenesis needs to be reevaluated in future studies