METHODS OF THE INFORMATIVENESS AND DIDACTIC COMPLEXITY ESTIMATION OF EDUCATIONAL CONCEPTS, PICTURES AND TEXTS

The article analyzes the problem of assessment of the informativeness (or informational content) and the didactic complexity of various learning material elements (educational concepts, pictures and education texts). The informativeness of learning material elements (LMEs) is considered equal to the number of concepts to be used for its presentation or the description. Under the didactic complexity of LME it is offered to understand the value proportional to the time or amount of the efforts demanded by the 5–class Russian schoolchild for his/her studying this LME. As all educational information is presented in a verbal form, to define the complexity of LME it is necessary to decompose LME into separate concepts, to estimate their separate difficulty, and then to summarize it. The article considers: 1) the estimation of difficulty of experimental and theoretical studying of a concept using the method of paired comparisons; 2) spreading out cards with scientific concepts on them in order of increasing complexity; 3) the calculation of the objects and links in the picture taking into account their abstractness degree; 4) the determination of terms (concepts) number in the text, accounting their complexity. Uniform criteria for estimation of the words (concepts) complexity in educational texts on natural-science disciplines are elaborated and the abstract-ness scale is constructed. The received results can be used to assess the complexity of textbooks in natural sciences. The developed estimation method of didactic complexity of the physics textbooks includes: 1) the estimation of the physics complexity of the textbook summing up the complexity of the physical objects, phenomena, experiments, statements and theories; 2) the measurement of mathematical complexity of the textbook by counting the number of formulas (considering their complexity) and drawings presenting mathematical abstractions (a vector, power lines, graphs); 3) the calculation of the total index of the textbook didactic complexity. With the help of this method 16 Russian physics textbooks for school and university have been analyzed, their distribution within the characteristics space "physical complexity - mathematical complexity" has been studied.  Article visualizations

Depression and Oral FTC/TDF Pre-exposure Prophylaxis (PrEP) Among Men and Transgender Women Who Have Sex With Men (MSM/TGW).

We conducted a longitudinal and cross-sectional analysis of depressive symptomology in iPrEx, a randomized, placebo-controlled trial of daily, oral FTC/TDF HIV pre-exposure prophylaxis (PrEP) in men and transgender women who have sex with men. Depression-related adverse events (AEs) were the most frequently reported severe or life-threatening AEs and were not associated with being randomized to the FTC/TDF arm (152 vs. 144 respectively OR 0.66 95 % CI 0.35-1.25). Center for Epidemiologic Studies Depression scale (CES-D) and a four questions suicidal ideation scale scores did not differ by arm. Participants reporting forced sex at anal sexual debut had higher CES-D scores (coeff: 3.23; 95 % CI 1.24-5.23) and were more likely to have suicidal ideation (OR 2.2; 95 % CI 1.09-4.26). CES-D scores were higher among people reporting non-condom receptive anal intercourse (ncRAI) (OR 1.46; 95 % CI 1.09-1.94). We recommend continuing PrEP during periods of depression in conjunction with provision of mental health services

Development of key soil health indicators for the Australian banana industry

To improve the sustainability and environmental accountability of the banana industry there is a need to develop a set of soil health indicators that integrate physical, chemical and biological soil properties. These indicators would allow banana growers, extension and research workers to improve soil health management practices. To determine changes in soil properties due to the cultivation of bananas, a paired site survey was conducted comparing soil properties under conventional banana systems to less intensively managed vegetation systems, such as pastures and forest. Measurements were made on physical, chemical and biological soil properties at seven locations in tropical and sub-tropical banana producing areas. Soil nematode community composition was used as a bioindicator of the biological properties of the soil. Soils under conventional banana production tended to have a greater soil bulk density, with less soil organic carbon (C) (both total C and labile C), greater exchangeable cations, higher extractable P, greater numbers of plant-parasitic nematodes and less nematode diversity, relative to less intensively managed plant systems. The organic banana production systems at two locations had greater labile C, relative to conventional banana systems, but there was no significant change in nematode community composition. There were significant interactions between physical, chemical and nematode community measurements in the soil, particularly with soil C measurements, confirming the need for a holistic set of indicators to aid soil management. There was no single indicator of soil health for the Australian banana industry, but a set of soil health indicators, which would allow the measurement of soil improvements should include: bulk density, soil C, pH, EC, total N, extractable P, ECEC and soil nematode community structure

Syphilis Predicts HIV Incidence Among Men and Transgender Women Who Have Sex With Men in a Preexposure Prophylaxis Trial

Background. Syphilis infection may potentiate transmission of human immunodeficiency virus (HIV). We sought to determine the extent to which HIV acquisition was associated with syphilis infection within an HIV preexposure prophylaxis (PrEP) trial and whether emtricitabine/tenofovir (FTC/TDF) modified that association. Methods. The Preexposure Prophylaxis Initiative (iPrEx) study randomly assigned 2499 HIV-seronegative men and transgender women who have sex with men (MSM) to receive oral daily FTC/TDF or placebo. Syphilis prevalence at screening and incidence during follow-up were measured. Hazard ratios for the effect of incident syphilis on HIV acquisition were calculated. The effect of FTC/TDF on incident syphilis and HIV acquisition was assessed. Results. Of 2499 individuals, 360 (14.4%) had a positive rapid plasma reagin test at screening; 333 (92.5%) had a positive confirmatory test, which did not differ between the arms (FTC/TDF vs placebo, P = .81). The overall syphilis incidence during the trial was 7.3 cases per 100 person-years. There was no difference in syphilis incidence between the study arms (7.8 cases per 100 person-years for FTC/TDF vs 6.8 cases per 100 person-years for placebo, P = .304). HIV incidence varied by incident syphilis (2.8 cases per 100 person-years for no syphilis vs 8.0 cases per 100 person-years for incident syphilis), reflecting a hazard ratio of 2.6 (95% confidence interval, 1.6–4.4; P < .001). There was no evidence for interaction between randomization to the FTC/TDF arm and incident syphilis on HIV incidence. Conclusions. In HIV-seronegative MSM, syphilis infection was associated with HIV acquisition in this PrEP trial; a syphilis diagnosis should prompt providers to offer PrEP unless otherwise contraindicated

The International Bathymetric Chart of the Arctic Ocean (IBCAO) Version 3.0

[1] The International Bathymetric Chart of the Arctic Ocean (IBCAO) released its first gridded bathymetric compilation in 1999. The IBCAO bathymetric portrayals have since supported a wide range of Arctic science activities, for example, by providing constraint for ocean circulation models and the means to define and formulate hypotheses about the geologic origin of Arctic undersea features. IBCAO Version 3.0 represents the largest improvement since 1999 taking advantage of new data sets collected by the circum-Arctic nations, opportunistic data collected from fishing vessels, data acquired from US Navy submarines and from research ships of various nations. Built using an improved gridding algorithm, this new grid is on a 500 meter spacing, revealing much greater details of the Arctic seafloor than IBCAO Version 1.0 (2.5 km) and Version 2.0 (2.0 km). The area covered by multibeam surveys has increased from ∼6% in Version 2.0 to ∼11% in Version 3.0