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Anecdotal data suggest great variation in breadth and depth of skeletal muscle coverage between undergraduate human anatomy (HA) and anatomy and physiology (A&P) courses. This manuscript is the second in a series (Reynolds A, Goodwin M, O'Loughlin V. D. "Adv Physiol Educ" 46: 309-318, 2022. doi:https://doi.org/10.1152/advan.00084.2021) that methodically assesses skeletal muscle content coverage across undergraduate HA and A&P courses. The authors developed an online skeletal muscle coverage survey and collected 342 responses worldwide, 156 from instructors of HA courses and 186 from A&P course instructors. Demographic results showed that HA courses are primarily taught at 4-year baccalaureate institutions, have relatively larger class sizes, and are more likely to use human (vs. animal) prosections or dissections. In contrast, A&P courses are primarily taught at community colleges, have relatively smaller class sizes, and are more likely to use animal (vs. human) dissections. HA courses tend to require their students to learn all skeletal muscle aspects (i.e., identification, action, attachments, innervation), whereas A&P courses tend to focus on muscle identification or action only. The proportions of courses that require identification of large, superficial skeletal muscles are similar between the two course types. However, HA courses are more likely to require their students to identify deeper and smaller muscles, including more distal appendicular muscles and pelvic muscles. These differences likely are due, in part, to the more anatomical focus of HA courses and the slightly different student populations between these courses. These findings provide much-needed information about muscular system coverage between HA and A&P courses and may guide instructor discussions about curricula. [For the first article in the series, "General Trends in Skeletal Muscle Coverage in Undergraduate Human Anatomy and Anatomy and Physiology Courses," see EJ1347509.]

Crop yields are projected to decrease under future climate conditions, and recent research suggests that yields have already been impacted. However, current impacts on a diversity of crops subnationally and implications for food security remains unclear. Here, we constructed linear regression relationships using weather and reported crop data to assess the potential impact of observed climate change on the yields of the top ten global crops–barley, cassava, maize, oil palm, rapeseed, rice, sorghum, soybean, sugarcane and wheat at ~20,000 political units. We find that the impact of global climate change on yields of different crops from climate trends ranged from -13.4% (oil palm) to 3.5% (soybean). Our results show that impacts are mostly negative in Europe, Southern Africa and Australia but generally positive in Latin America. Impacts in Asia and Northern and Central America are mixed. This has likely led to ~1% average reduction (-3.5 X 1013 kcal/year) in consumable food calories in these ten crops. In nearly half of food insecure countries, estimated caloric availability decreased. Our results suggest that climate change has already affected global food production. [ABSTRACT FROM AUTHOR]

Background and aims: Cannabis is one of the most commonly used substances among adolescents and young adults. Earlier age at cannabis initiation is linked to adverse life outcomes, including multi‐substance use and dependence. This study estimated the heritability of age at first cannabis use and identified associations with genetic variants. Methods: A twin‐based heritability analysis using 8055 twins from three cohorts was performed. We then carried out a genome‐wide association meta‐analysis of age at first cannabis use in a discovery sample of 24 953 individuals from nine European, North American and Australian cohorts, and a replication sample of 3735 individuals. Results: The twin‐based heritability for age at first cannabis use was 38% [95% confidence interval (CI) = 19–60%]. Shared and unique environmental factors explained 39% (95% CI = 20–56%) and 22% (95% CI = 16–29%). The genome‐wide association meta‐analysis identified five single nucleotide polymorphisms (SNPs) on chromosome 16 within the calcium‐transporting ATPase gene (ATP2C2) at P < 5E‐08. All five SNPs are in high linkage disequilibrium (LD) (r2 > 0.8), with the strongest association at the intronic variant rs1574587 (P = 4.09E‐09). Gene‐based tests of association identified the ATP2C2 gene on 16q24.1 (P = 1.33e‐06). Although the five SNPs and ATP2C2 did not replicate, ATP2C2 has been associated with cocaine dependence in a previous study. ATP2B2, which is a member of the same calcium signalling pathway, has been associated previously with opioid dependence. SNP‐based heritability for age at first cannabis use was non‐significant. Conclusion: Age at cannabis initiation appears to be moderately heritable in western countries, and individual differences in onset can be explained by separate but correlated genetic liabilities. The significant association between age of initiation and ATP2C2 is consistent with the role of calcium signalling mechanisms in substance use disorders. [ABSTRACT FROM AUTHOR]

Background: Concern over human breast milk contamination with the pesticide DDT (1,1,1-trichloro-2,2-bis(chlorodiphenyl)ethane) has prompted numerous studies around the world during the last five decades. This article examines trends in reported DDT levels, and the apparent effect of restrictions on DDT use., Methods: More than 130 published values for DDT in human milk since 1951 were compiled, and trend lines were fit for regions of the world., Results: Population means have declined in much of the world, from 5000-10000 microg DDT/kg milk fat to around 1000 today in many areas. Although different regions have different means, the decline seen in various countries corresponds to their restricting DDT use., Discussion: DDT concentrations in human milk have declined in most areas of the world, consistent with restrictions on its use. Nevertheless, levels can be high in areas still using DDT, even higher than the World Health Organization's recommended limit for infants. These results indicate that population averages can be reduced by a predictable amount as DDT use is restricted.

Background: The mortality level from all causes is different between populations and it has decreased for both men and women in most countries in the last decades. However, there is a difference in the male/female sex ratio of mortality between populations and its time trends and the reasons for these differences remain unclear., Methods: The sex ratio of all-cause mortality and the main causes of death, i.e. total cardiovascular disease and cancer, for 30 populations in 1988 (mean of 1987-1989), and the time trends of the sex ratio for 27 populations are analysed., Results: Large differences in the sex ratio of mortality exist among the studied populations. The sex ratio of all-cause, total cardiovascular and cancer mortality markedly increased in most countries during recent decades., Conclusions: The sex ratio of all-cause mortality and its time trends correlated significantly and positively with the sex ratio of mortality and its time trends from total cardiovascular disease and cancer. The differences of the sex ratio of mortality and their time trends between populations cannot be explained by genetic factors. They could be attributed to differences in life style. A different exposure and different reaction to the risk factors of cardiovascular diseases and cancer, e.g. saturated fat intake, alcohol intake and smoking habits, between men and women are considered to be the main causes for these differences in the sex ratio of mortality.

Reports from developed countries world wide describing the outcome for infants of very low birthweight (VLBW, less than or equal to 1500 g) born since 1946 show that, in general, mortality rates and the prevalence of major handicap in survivors were high until 1960. Since then the chances of healthy survival have trebled, whereas the handicap-rate has remained stable and relatively low at 6--8% of VLBW live births.