The secular trend of intelligence test scores: The Danish experience for young men born between 1940 and 2000

The present study investigated the Danish secular trend of intelligence test scores among young men born between 1940 and 2000, as well as the possible associations of birth cohort changes in family size, nutrition, education, and intelligence test score variability with the increasing secular trend. The study population included all men born from 1940 to 2000 who appeared before a draft board before 2020 (N = 1,556,770). At the mandatory draft board examination, the approximately 19-year-old men underwent a medical examination and an intelligence test. In the statistical analyses, the IQ mean and standard deviation (SD) were estimated separately for each of the included annual birth cohorts based on information from birth cohorts with available total intelligence test scores for all tested individuals (i.e. 1940–1958 and 1987–2000; the mean and SD were interpolated for the intermediate birth cohorts). Moreover, the possible associations with birth cohort changes in family size, height as a proxy for nutritional status, education, and IQ variability were investigated among those birth cohorts for whom a secular increase in intelligence test scores was found. The results showed that the estimated mean IQ score increased from a baseline set to 100 (SD: 15) among individuals born in 1940 to 108.9 (SD: 12.2) among individuals born in 1980, since when it has decreased. Focusing on the birth cohorts of 1940–1980, for whom a secular increase in intelligence test scores was found, birth cohort changes in family size, height, and education explained large proportions of the birth cohort variance in mean intelligence test scores, suggesting that these factors may be important contributors to the observed Flynn effect in Denmark.

New photometric studies for two deep, low-mass ratio overcontact binaries: Y Sex and V1363 Ori

We present new photometry for two contact binaries, Y Sex and V1363 Ori, which were observed by three small telescopes in China. By using the W-D method, the absolute parameters are updated from new BVR light curves and previous radial velocity curves. Results identify that two binaries are deep, low-mass ratio (DLMR) overcontact binaries with q ⩽ 0.25 and f ⩾ 50%. From the temperature-luminosity diagram, the primary components are slightly evolved main-sequence stars, whose evolutionary ages are ∼2.51 Gyr for Y Sex and ∼3.56 Gyr for V 1363 Ori, respectively. From the (O − C) curves, it is found that the orbital periods may be undergoing secular increase with cyclic variations, which may be interpreted either by magnetic activity cycles or by the light-time orbit effect. With period increasing, this kind of DLMR overcontact binaries, such as Y Sex and V1363 Ori, will evolve into the rapid-rotating single stars.

Data-based estimates of interannual sea–air CO₂ flux variations 1957–2020 and their relation to environmental drivers

This study considers year-to-year and decadal variations as well as secular trends of the sea–air CO2 flux over the 1957–2020 period, as constrained by the pCO2 measurements from the SOCAT data base. In a first step, we relate interannual anomalies in ocean-internal carbon sources and sinks to local interannual anomalies in sea surface temperature (SST), the temporal changes of SST (dSST/dt), and squared wind speed (u2), employing a multi-linear regression. In the tropical Pacific, we find interannual variability to be dominated by dSST/dt, as arising from variations in the upwelling of colder and more carbon-rich waters into the mixed layer. In the eastern upwelling zones as well as in circumpolar bands in the high latitudes of both hemispheres, we find sensitivity to wind speed, compatible with the entrainment of carbon-rich water during wind-driven deepening of the mixed layer and wind-driven upwelling. In the Southern Ocean, the secular increase in wind speed leads to a secular increase in the carbon source into the mixed layer, with an estimated reduction of the sink trend in the range 17 to 42 %. In a second step, we combined the result of the multi-linear regression and an explicitly interannual pCO2-based additive correction into a “hybrid” estimate of the sea–air CO2 flux over the period 1957–2020. As a pCO2 mapping method, it combines (a) the ability of a regression to bridge data gaps and extrapolate into the early decades almost void of pCO2 data based on process-related observables and (b) the ability of an autoregressive interpolation to follow signals even if not represented in the chosen set of explanatory variables. The “hybrid” estimate can be applied as ocean flux prior for atmospheric CO2 inversions covering the whole period of atmospheric CO2 data since 1957.

Prevalence and Interpretation of Recent Trends in Rates of Pervasive Developmental Disorders

The aims of this article are to provide an up-to-date review of the methodological features and substantive results of published epidemiological surveys of the prevalence of pervasive developmental disorders (PDD). This article updates previous reviews (1, 2) with the inclusion of new studies made available since then. The specific questions addressed inthis article are: a) how are cases of PDD defined and identified in epidemiological surveys?; b) what are the best estimates for the prevalence of autism and related pervasive developmental disorders considering the methodological implications of the surveys, and c) what interpretation can be given to time trends observed in prevalence rates of PDDs given the hypothesized secular increase in PDDs?

Prevalence and Interpretation of Recent Trends in Rates of Pervasive Developmental Disorders

The aims of this article are to provide an up-to-date review of the methodological features and substantive results of published epidemiological surveys of the prevalence of pervasive developmental disorders (PDD). This article updates previous reviews (1, 2) with the inclusion of new studies made available since then. The specific questions addressed inthis article are: a) how are cases of PDD defined and identified in epidemiological surveys?; b) what are the best estimates for the prevalence of autism and related pervasive developmental disorders considering the methodological implications of the surveys, and c) what interpretation can be given to time trends observed in prevalence rates of PDDs given the hypothesized secular increase in PDDs?

Impact of a comprehensive tobacco control policy package on acute myocardial infarction and stroke hospital admissions in Beijing, China: interrupted time series study

ObjectiveTo evaluate a comprehensive tobacco control policy package on hospital admissions for acute myocardial infarction (AMI) and stroke in a global city.DesignInterrupted time series study.SettingBeijing, China.Population31 707 AMI and 128 116 stroke hospital admissions recorded by the Beijing Medical Claim Data for Employees in 17.7 million residents from January 2013 to June 2017.InterventionThe policy package including all components of MPOWER has been implemented since June 2015.Main outcome measuresThe immediate change of AMI and stroke hospital admissions and the annual change in the secular trend.ResultsThere was a secular increase trend for the crude hospital admission rates of AMI and stroke during the observational period. After implementation of the policy, immediate reductions were observed in the hospital admissions for both AMI (−5.4%, 95% CI −10.0% to −0.5%) and stroke (−5.6%, 95% CI −7.8% to −3.3%). In addition, the secular increase trend for stroke was slowed down by −15.3% (95% CI −16.7% to −13.9%) annually. Compared with the hypothetical scenario where the policy had not taken place, an estimated 18 137 (26.7%) stroke hospital admissions had been averted during the 25 months of postpolicy period.ConclusionsThe results indicated significant health benefits on cardiovascular morbidity after the Beijing tobacco control policy package, which highlighted the importance for a comprehensive tobacco control policy at the national level in China. Similar tobacco control policy which consists of all components of MPOWER is urgently needed in other areas, especially in settings with high tobacco consumption, to achieve greater public health gains.

Secular changes in anthropometric measurements of schoolchildren in Ankara, Turkey (1950–2017)

This study aimed to examine the physical growth of Turkish children and determine secular changes in their height and other anthropometric measurements since 1950. For this purpose, three cross-sectional surveys of a total of 4,902 healthy schoolchildren from Ankara (2,490 boys and 2,412 girls) between the ages of 6 and 17 years conducted in 1950, 2005 and 2017 were studied. Body height and sitting height were measured, centile curves were constructed using the LMS method, and sitting height/height ratio was calculated. The results of this study demonstrated positive secular changes in height and sitting height. The increasing rate of height for boys was approximately 2.5 cm/decade for their respective pubertal ages, whereas for girls, the rate was approximately 1.9 cm/decade at ages 9, 10 and 12; however, at the age of 11, the increment in girls was over 2 cm/decade. Data sets presented sexual differences at most ages, arising due to a difference in response to environmental and socio-economic conditions. However, due to the socio-economic fluctuations in Turkey, secular increase was not comparable to the increase experienced within developed countries; therefore a continuation of this secular increase can be expected in the near future.

Competition, Markups, and Predictable Returns

This paper jointly examines the link between competition and expected returns in the time series and in the cross-section. To this end, we build a general equilibrium model where markups vary because of firm entry with oligopolistic competition. When concentration is high, markups are more sensitive to entry risk. We find that higher markups are associated with higher expected returns over time and across industries, in line with the data. The model can also quantitatively account for the persistent rise in aggregate risk premiums and macroeconomic volatility associated with the secular increase trend industry concentration since the mid-1980s.

Varying Physical Constants, Astrometric Anomalies, Redshift and Hubble Units

We have developed a cosmological model by allowing the speed of light c, gravitational constant G and cosmological constant Λ in the Einstein filed equation to vary in time, and solved them for Robertson-Walker metric. Assuming the universe is flat and matter dominant at present, we obtain a simple model that can fit the supernovae 1a data with a single parameter almost as well as the standard ΛCDM model with two parameters, and which has the predictive capability superior to the latter. The model, together with the null results for the variation of G from the analysis of lunar laser ranging data determines that at the current time G and c both increase as dG/dt = 5.4GH0 and dc/dt = 1.8cH0 with H0 as the Hubble constant, and Λ decreases as dΛ/dt = −1.2ΛH0. This variation of G and c is all what is needed to account for the Pioneer anomaly, the anomalous secular increase of the moon eccentricity, and the anomalous secular increase of the astronomical unit. We also show that the Planck’s constant ħ increases as dħ/dt = 1.8ħH0 and the ratio D of any Hubble unit to the corresponding Planck unit increases as dD/dt = 1.5DH0. We have shown that it is essential to consider the variation of all the physical constants that may be involved directly or indirectly in a measurement rather than only the one whose variation is of interest.