Search

Monogenesis of language is widely accepted, but the conventional argument seems to be mistaken; a simple probabilistic model shows that polygenesis is likely. Other prehistoric inventions are discussed, as are problems in tracing linguistic lineages. Language is a system of representations; within such a system, words can evoke complex and systematic responses. Along with its social functions, language is important to humans as a mental instrument. Indeed, the invention of language,that is the accumulation of symbols to represent emotions, objects, and acts may be the most important event in human evolution, because so many developments follow from it. For example, Edward Sapir speculated that some embryonic form of language must have been available to early man to help him fashion tools from stone (Sapir,1921). Sophisticated biface stone tools date to early Homo erectus some 1.5 million years ago, suggesting a similar age for language. This paper considers whether the invention of language occurred at only one pre-historic site or at several sites. In other words, did language emerge by monogenesis or polygenesis? Early thinkers believed in monogenesis, against a background of divine creation. Perhaps the best known account is the biblical story of Adam giving names to plants and animals in the Garden of Eden. Similar legends are found among many peoples. Modern linguists too assume monogenesis, but on probabilistic grounds (see, for instance, Southworth and Daswani, 1974, p.314). The argument seems to be that the invention of language is an extremely unlikely event, because symbolization involves abstraction and requires synchronized insight by several individuals; therefore, the probability of occurrence at more than one site must be vanishingly small. We have found no explicit quantitative treatment of this question in the literature, but the underlying logic has to be the multiplication of probabilities. If p is small at one site,then p.p for two sites is smaller still, and so on. This reasoning is false, as we show here. The fallacy lies in the focus on two particular sites rather than consideration of all pairs of sites.

BACKGROUND AND OBJECTIVES: Although the limitations of BMI have long been recognized, there are recent concerns that it is not a good screening tool for adiposity. We therefore examined the cross-sectional relation of BMI to adiposity among 6923 8- to 19-year-olds in the National Health and Nutrition Survey from 2011 through 2018. METHODS: Participants were scanned with dual-energy x-ray absorptiometry. Adiposity was expressed as fat mass index (FMI, fat mass kg ÷ m²) and percentage of body fat (%fat). Lean mass was expressed as lean mass index (LMI, lean mass ÷ m²). Regression models and 2 x2 tables were used to assess the relation of BMI to FMI,%fat, and LMI. RESULTS: Age and BMI accounted (R²) for 90% to 94% of the variability of FMI and LMI in each sex. Associations with %fat were weaker (R²s ~0.70). We also examined the screening abilities of a BMI ≥ Centers for Disease Control and Prevention 95th percentile for high levels of adiposity and LMI. Cut points were chosen so that prevalences of high values of these variables would be similar to that for high BMI. Of participants with a high BMI, 88% had a high FMI, and 76% had a high %fat. Participants with a high BMI were 29 times more likely to have a high FMI than those with lower BMIs; comparable relative risks were 12 for high %fat and 14 for high LMI. CONCLUSIONS: Despite its limitations, a high BMI is a very good screening tool for identifying children and adolescents with elevated adiposity. [ABSTRACT FROM AUTHOR]

Acetylene, ethene, and ethane are products from the degradation of trichloroethene (TCE) in contaminated aquifers. However, the volatility of these gases makes it challenging to avoid excessive losses during sampling. The objective of this study was to compare the quantification of acetylene, ethene, and ethane using passive vapor diffusion (PVD) samplers vs. conventional low‐flow groundwater collection. Samples were obtained from 8 to 13 monitoring wells at three sites that show potential for biotic and abiotic degradation of TCE in fractured rock aquifers. Method reporting limits (MRLs) for the PVD samplers were 0.25 μg/L for acetylene (0.0094 μM) and 0.28 μg/L for ethene and ethane (0.0099 and 0.0092 μM, respectively); the MRLs for conventional low‐flow groundwater samples were ~40% higher. For two of the sites, the maximum concentrations of acetylene, ethene, and ethane obtained with the PVD samplers were comparable to the conventional low‐flow samples. The frequency of detection for these gases with the PVD samplers was also comparable to conventional low‐flow groundwater sampling. For one of the sites with higher levels of acetylene (maximum of 13 μg/L), the concentrations from the PVD samplers were approximately twofold higher than those with conventional low‐flow groundwater sampling. Based on robust detection of acetylene, ethene, and/or ethane, it appears likely that degradation of TCE is occurring at the three sites that were sampled. The use of PVD samplers can reduce the possibility of false negative results to provide another line of evidence in support of natural attenuation. [ABSTRACT FROM AUTHOR]