Eddy covariance measurements of the surface energy balance associated with a localised coral bleaching event, Heron Reef, Great Barrier Reef, Australia

While their ecological, economical and societal values are irrefutable, an uncertain future exists for coral reefs and numerous studies suggest that the threat of coral bleaching will worsen under global warming. Despite the association between global warming and coral reef health, there is a paucity of data relating to the exchanges of heat, moisture and momentum between the atmosphere and the reef surface during bleaching episodes. Understanding these key reef-atmosphere interactions is essential for identifying the processes which control the thermal environment of water on the reef. In this paper we present new direct in situ measurements of radiation transfers and sensible and latent heat fluxes associated with an observed localised coral bleaching event at Heron Reef, in the southern Great Barrier Reef. Measurements were made during a three day period in February 2009 using the Eddy Covariance method. Under the influence of a weak barometric pressure gradient, clear skies and light north easterly winds, daily net radiation peaked at more than 800 W m2, with up to 95% of the net radiation during the morning being partitioned into heating the water column, substrate and benthic cover. Heating was exacerbated by a midafternoon low tide, and low wind speeds resulted in reduced evaporative cooling of the water surface. As a result, daily maximum water surface temperatures exceeded 34°C and near-bottom temperatures 33°C. Such conditions in conjunction with limited horizontal heat transfer due to the pooling of reef waters at the site meant that the water surface and near-bottom water temperatures exceeded 30°C for 27% and 38% of the duration of the observation period respectively resulting in widespread coral bleaching

A Social Security Forecasting and Simulation Model

This paper presents and validates a multiregional neoclassical economic- demographic growth model developed by the IIASA Social Security Reform Project. This model is intended to study linkages between population age distribution, the macroeconomy, the nature of pension arrangements, the intergenerational distribution of income and wealth, and international capital flows. In this paper, we concentrate on the model in single-region form, showing that: (i) reasonable exogenous assumptions give rise to a reasonable long-run model solution; (ii) when exogenous assumptions or model parameters are changed, the model performs sensibly on a baseline-vs.-alternative basis; and (iii) model projection results are reasonably robust to selection of demographic scenario and exogenous assumptions regarding household saving and labor supply; they are sensitive, however, to the selection of the parameters of the core production function

Suicide in Eastern Europe, the Commonwealth of Independent States, and the Baltic Countries: Social and Public Health Determinants

While suicide is a major public health problem worldwide, the countries of the former Soviet Union, including the Baltic States and the Commonwealth of Independent States (CIS), have some of the highest rates in the world. High suicide rates across Eastern Europe have been correlated with the post-Soviet transitional period and the societal changes associated with that transition. Many scholars have speculated that the sudden collapse of the paternalistic Soviet system and the introduction of a market economy - and the psychosocial distress that ensued.contributed to the suicide mortality crisis that most of the former Soviet republics experienced in the 1990s. It is unclear whether the transitional period has ended or is still ongoing. While suicide mortality rates in many countries have declined since then, they remain alarmingly high. In some countries, such as Belarus, the rates have increased. From September 14 to 15, 2010, suicidologists and other scholars and professionals with expertise in suicide and suicide prevention gathered in Tallinn, Estonia, to discuss the evidence base for social and public health determinants of suicide in the Baltic States, the CIS, and Eastern Europe. The participants identified research and data gaps that, if filled, would strengthen the foundation for developing effective suicide prevention policies and programs. This report summarizes the presentations and discussions that took place during the conference

Differential Effects of Thiazolidinediones on Adipocyte Growth and Recruitment in Zucker Fatty Rats

Background: Adipose tissue grows by two mechanisms: hyperplasia (cell number increase) and hypertrophy (cell size increase). Thiazolidinediones are insulin-sensitizing peroxisome proliferator-activated receptor gamma agonists that are known to affect the morphology of adipose tissue. Methodology: In this study, adipose cell-size probability distributions were measured in six Zucker fa/fa rats over a period of 24 days, from four weeks of age, using micro-biopsies to obtain subcutaneous (inguinal) fat tissue from the animals. Three of the rats were gavaged daily with rosiglitazone, a thiazolidinedione, and three served as controls. These longitudinal probability distributions were analyzed to obtain the rate of increase in cell-size diameter in rosiglitazone-treated animals, and the hyperplasia induced by treatment quantitatively. Conclusions: We found that treatment leads to hypertrophy that leads to an approximately linear rate of cell diameter increase (2 mm/day), and that the hyperplasia evident in treated animals occurs largely within the first eight days of treatment. The availability of additional lipid storage due to treatment may alleviate lipotoxicity and thereby promote insulin sensitivity. The hypothesis that a TZD regimen involving repeated treatments of limited duration may suffice for improvements in insulin sensitivity merits further investigation

Assessing How Pre-requisite Skills Affect Learning of Advanced Concepts

Students often struggle with advanced computing courses, and comparatively few studies have looked into the reasons for this. It seems that learners do not master the most basic concepts, or forget them between courses. If so, remedial practice could improve learning, but instructors rightly will not use scarce time for this without strong evidence. Based on personal observation, program tracing seems to be an important pre-requisite skill, but there is yet little research that provides evidence for this observation. To investigate this, our group will create theory-based assessments on how tracing knowledge affects learning of advanced topics, such as data structures, algorithms, and concurrency. This working group will identify relevant concepts in advanced courses, then conceptually analyze their pre-requisites and where an imagined student with some tracing difficulties would encounter barriers. The group will use this theory to create instructor-usable assessments for advanced topics that also identify issues caused by poor pre-requisite knowledge. These assessments may then be used at the start and end of advanced courses to evaluate to what extent students\u2019 difficulties with the advanced course originate from poor pre-requisite knowledge

Terahertz electrometry via infrared spectroscopy of atomic vapor

In recent years, the characterisation of radiation falling within the so-called ‘terahertz (THz) gap’ has become an ever more prominent issue due to the increasing use of THz systems in applications such as nondestructive testing, security screening, telecommunications, and medical diagnostics. THz detection technologies have advanced rapidly, yet traceable calibration of THz radiation remains challenging. In this paper, we demonstrate a system of electrometry in which a THz signal can be characterized using laser spectroscopy of highly excited (Rydberg) atomic states. We report on proof-of-principle measurements that reveal a minimum detectable THz electric field amplitude of 1.070.06 V/m at 1.06 THz (3 ms detection), corresponding to a THz power at the atomic cell of approximately 3.4 nW. Due to the relative simplicity and cryogen-free nature of this system, it has the potential to provide a route to a SI traceable ‘atomic candle’ for THz calibration across the terahertz frequency range, and provide an alternative to calorimetric methods

Investigation of False Positive Results with an Oral Fluid Rapid HIV-1/2 Antibody Test

BACKGROUND: In March 2004, the OraQuick® rapid HIV antibody test became the first rapid HIV test approved by the US Food and Drug Administration for use on oral fluid specimens. Test results are available in 20 minutes, and the oral fluid test is non-invasive. From August 2004–June 2005, we investigated a sudden increase in false-positive results occurring in a performance study of OraQuick® oral-fluid rapid HIV tests in Minnesota. METHODOLOGY/PRINCIPAL FINDINGS: In a field investigation, we reviewed performance study data on oral-fluid and whole-blood OraQuick® rapid HIV test device lots and expiration dates and assessed test performance and interpretation with oral-fluid and whole-blood specimens by operators who reported false-positive results. We used multivariate logistic regression to evaluate client demographic and risk characteristics associated with false-positive results. Next, we conducted an incidence study of false-positive OraQuick rapid HIV tests in nine US cities and tested both oral-fluid and finger-stick whole-blood specimens from clients; reactive tests were confirmed with Western blot. Sixteen (4.1%) false-positive oral-fluid results occurred in the performance study from April 15, 2004 through August 31, 2004 with unexpired devices from six test lots among 388 HIV-uninfected clients (specificity, 95.9%; 95% CI: 93.4–97.6). Three test operators who had reported false-positive results performed and interpreted the test according to package-insert instructions. In multivariate analysis, only older age was significantly associated with false-positive results (adjusted odds ratio = 4.5, 95% CI: 1.2–25.7). In the incidence study, all valid oral-fluid and whole-blood results from 2,268 clients were concordant and no false-positive results occurred (100% specificity). CONCLUSIONS/SIGNIFICANCE: The field investigation did not identify a cause for the increase in false-positive oral-fluid results, and the incidence study detected no false-positive results. The findings suggest this was an isolated cluster; the test's overall performance was as specified by the manufacturer

Enrollment in HIV Care Two Years after HIV Diagnosis in the Kingdom of Swaziland: An Evaluation of a National Program of New Linkage Procedures

To improve early enrollment in HIV care, the Swaziland Ministry of Health implemented new linkage procedures for persons HIV diagnosed during the Soka Uncobe male circumcision campaign (SOKA, 2011–2012) and the Swaziland HIV Incidence Measurement Survey (SHIMS, 2011). Abstraction of clinical records and telephone interviews of a retrospective cohort of HIV-diagnosed SOKA and SHIMS clients were conducted in 2013–2014 to evaluate compliance with new linkage procedures and enrollment in HIV care at 92 facilities throughout Swaziland. Of 1,105 clients evaluated, within 3, 12, and 24 months of diagnosis, an estimated 14.0%, 24.3%, and 37.0% enrolled in HIV care, respectively, after adjusting for lost to follow-up and non-response. Kaplan-Meier functions indicated lower enrollment probability among clients 14–24 (P = 0.0001) and 25–29 (P = 0.001) years of age compared with clients > 35 years of age. At 69 facilities to which clients were referred for HIV care, compliance with new linkage procedures was low: referral forms were located for less than half (46.8%) of the clients, and few (9.6%) were recorded in the appointment register or called either before (0.3%) or after (4.9%) their appointment. Of over one thousand clients newly HIV diagnosed in Swaziland in 2011 and 2012, few received linkage services in accordance with national procedures and most had not enrolled in HIV care two years after their diagnosis. Our findings are a call to action to improve linkage services and early enrollment in HIV care in Swaziland

Predictors of Unrecognized HIV Infection Among Poor and Ethnic Men Who Have Sex with Men in Los Angeles

This study evaluates associations between unrecognized HIV infection and demographic factors, internalized homonegativity, drug use, and sexual behaviors among HIV positive men who have sex with men (MSM). We analyzed data from 347 HIV positive participants from the Los Angeles site for NIDA’s Sexual Acquisition and Transmission of HIV-Cooperative Agreement Program. Participants were HIV positive MSM and MSM/W and predominantly African American (36.0%) or Latino (38.7%), and unemployed (82.8%). Results from a multivariate logistic regression suggest that, compared to HIV positive participants who correctly reported their HIV positive status, being African-American (OR: 9.81, CI: 1.2–77.9) or Latino (OR: 10.92, CI: 1.3–88.4) rather than White, MSM/W rather than MSM (OR: 3.24, CI: 1.09–9.62), and having higher homonegativity scores (OR: 1.22, CI: 1.02–1.4) is associated with unrecognized HIV infection, controlling for age, education, and homelessness. Findings provide some immediate evidence to help craft HIV prevention interventions