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Timing of developmental milestones, such as age at first walking, is associated with later diagnoses of neurodevelopmental disorders. However, its relationship to genetic risk for neurodevelopmental disorders in the general population is unknown. Here, we investigate associations between attainment of early-life language and motor development milestones and genetic liability to autism, attention deficit hyperactivity disorder (ADHD), and schizophrenia.
We use data from a genotyped sub-set (N = 25699) of children in the Norwegian Mother, Father and Child Cohort Study (MoBa). We calculate polygenic scores (PGS) for autism, ADHD, and schizophrenia and predict maternal reports of children's age at first walking, first words, and first sentences, motor delays (18 months), and language delays and a generalised measure of concerns about development (3 years). We use linear and probit regression models in a multi-group framework to test for sex differences.
We found that ADHD PGS were associated with earlier walking age (β = −0.033, padj < 0.001) in both males and females. Additionally, autism PGS were associated with later walking (β = 0.039, padj = 0.006) in females only. No robust associations were observed for schizophrenia PGS or between any neurodevelopmental PGS and measures of language developmental milestone attainment.
Genetic liabilities for neurodevelopmental disorders show some specific associations with the age at which children first walk unsupported. Associations are small but robust and, in the case of autism PGS, differentiated by sex. These findings suggest that early-life motor developmental milestone attainment is associated with genetic liability to ADHD and autism in the general population.
The ways in which cultural groups vary from one another has long been a matter of everyday observation. The construction of valid and reliable measures of these differences remains problematic. Comparisons of survey responses rest on assumptions about the functional equivalence of translated items and of the assumptions that respondents make about the meaning of such surveys. This chapter explores the different possible levels of measurement equivalence. Psychological variables are most frequently latent rather than directly observable. Philosophers of science have discussed how best to address the challenges one faces when working with latent variables. If we are to claim that latent variables such as individualism or collectivism can account for particular differences between groups, specific counterfactual theorising is required as to the limiting circumstances under which such effects will or will not occur. At a more practical level, we can note that differences are frequently found in the characteristic survey response styles of respondents from different cultural groups, but decisions as to whether or when to discount such variations rest on answers to the more basic philosophical questions raised in the earlier section of this chapter.
Matrix positivity is a central topic in matrix theory: properties that generalize the notion of positivity to matrices arose from a large variety of applications, and many have also taken on notable theoretical significance, either because they are natural or unifying. This is the first book to provide a comprehensive and up-to-date reference of important material on matrix positivity classes, their properties, and their relations. The matrix classes emphasized in this book include the classes of semipositive matrices, P-matrices, inverse M-matrices, and copositive matrices. This self-contained reference will be useful to a large variety of mathematicians, engineers, and social scientists, as well as graduate students. The generalizations of positivity and the connections observed provide a unique perspective, along with theoretical insight into applications and future challenges. Direct applications can be found in data analysis, differential equations, mathematical programming, computational complexity, models of the economy, population biology, dynamical systems and control theory.
Clostridioides difficile infection (CDI) remains a significant public health concern, resulting in excess morbidity, mortality, and costs. Additional insight into the burden of CDI in adults aged <65 years is needed.
A 6-year retrospective cohort study was conducted using data extracted from United States Veterans Health Administration electronic medical records.
Patients aged 18–64 years on January 1, 2011, were followed until incident CDI, death, loss-to-follow-up, or December 31, 2016. CDI was identified by a diagnosis code accompanied by metronidazole, vancomycin, or fidaxomicin therapy, or positive laboratory test. The clinical setting of CDI onset was defined according to 2017 SHEA-IDSA guidelines.
Of 1,073,900 patients, 10,534 had a CDI during follow-up. The overall incidence rate was 177 CDIs per 100,000 person years, rising steadily from 164 per 100,000 person years in 2011 to 189 per 100,000 person years in 2016. Those with a CDI were slightly older (55 vs 51 years) and sicker, with a higher baseline Charlson comorbidity index score (1.4 vs 0.5) than those without an infection. Nearly half (48%) of all incident CDIs were community associated, and this proportion rose from 41% in 2011 to 56% in 2016.
The findings from this large retrospective study indicate that CDI incidence, driven primarily by increasing community-associated infection, is rising among young and middle-aged adult Veterans with high service-related disability. The increasing burden of community associated CDI in this vulnerable population warrants attention. Future studies quantifying the economic and societal burden of CDI will inform decisions surrounding prevention strategies.
In 1921, when Sir Ernest Shackleton was planning his circum-Antarctic expedition on the R.Y.S. Quest, he was eager to appoint a suitably qualified young person as a cabin boy or deck hand. He expressed great admiration for the Boy Scout Movement and its founder, Sir Robert Baden-Powell. Discussions between them led to Shackleton advertising for a Boy Scout to accompany him on the expedition, believing that the experience would greatly benefit the youngster's character, as well as providing much positive publicity for the expedition. He selected two young Scouts but, while much has been written about James Marr, no account has been written about the younger boy, Norman Mooney. This is because he was unable to cope with continuous seasickness and had to return home after only four weeks at sea. This account provides some little-known detail about Mooney and why he was selected, and about Shackleton's sensitive recruiting procedure.
The drafting, publishing and subsequent reproduction of Edward Wilson's evocative and sinisterly premonitory poem, The Barrier Silence, is examined. It was written in October 1911 for Part 3 of the South Polar Times (SPT), Vol. 3, prepared and ‘published’ at Robert Falcon Scott's British Antarctic (Terra Nova) Expedition hut at Cape Evans, Ross Island, shortly before Wilson, Scott and three other members set off on the ill-fated South Pole journey. Wilson contributed most of the illustrative material for all three volumes of the SPT, but this poem is the only written article attributed to him, although it is possible that he was also the author of an anonymous poem. Events that may have influenced Wilson to write his poem are also considered.
The Antarctic Treaty recognizes the outstanding scientific values of the Antarctic environment through the designation of Antarctic Specially Protected Areas (ASPAs) that have rigorous management plans specific to each site. Deception Island has the largest concentration of rare bryophyte species and communities in Antarctica, while also offering substantial opportunities for research in a range of scientific disciplines due to its volcanic nature. As a result, conflicts between research interests and conservation goals may arise. On the summit ridge of Caliente Hill severe trampling damage to the moss assemblages growing in association with localized geothermal activity was observed. The range of species affected included the entire known population of Schistidium deceptionense, an endemic moss known only from this site, as well as other very rare Antarctic mosses (Ditrichum ditrichoideum, Bryum orbiculatifolium, Bucklandiella subcrispipila, Pohlia wahlenbergii and Dicranella hookeri). A photomapping study was undertaken to characterize further the status of the site and monitor changes within it. Increased awareness, co-ordination of activities and a spatial zoning within the site could help mitigate damage from permitted activities. Nevertheless, prioritization of longer term conservation goals over short-term research interests may ultimately be necessary where local human impact cannot be managed by other means.