Secular Increase Research Articles

DEEP, LOW MASS RATIO OVERCONTACT BINARY SYSTEMS. XIII. DZ PISCIUM WITH INTRINSIC LIGHT VARIABILITY

New multi-color photometry for the eclipsing binary DZ Psc was performed in 2011 and 2012 using the 85 cm telescope at the Xinglong Station of the National Astronomical Observatories of China. Using the updated Wilson-Devinney (W-D) code, we deduced two sets of photometric solutions. The overcontact degree is f = 89.7(+/- 1.0)%, identifying DZ Psc as a deep, low mass ratio overcontact binary. The asymmetric light curves (i.e., LC2 in 2012) were modeled by a hot spot on the primary star. Based on all of the available light minimum times, we discovered that the orbital period of DZ Psc may be undergoing a secular period increase with a cyclic variation. The modulated period and semi-amplitude of this oscillation are P-mod = 11.89(+/- 0.19) yr and A = 0.0064(+/- 0.0006) days, which may be possibly attributed to either cyclic magnetic activity or light-time effect due to the third body. The long-term period increases at a rate of dP/dt = +7.43(+/- 0.17) x 10(-7) days yr(-1), which may be interpreted as conserved mass transfer from the less massive component to the more massive one. With mass transferring, DZ Psc will finally merge into a rapid-rotation single star when J(spin)/J(orb) > 1/3.

Pond-Derived Organic Carbon Driving Changes in Arsenic Hazard Found in Asian Groundwaters

Microbially mediated reductive processes involving the oxidation of labile organic carbon are widely considered to be critical to the release of arsenic into shallow groundwaters in South and Southeast Asia. In areas where there is significant pumping of groundwater for irrigation the involvement of surface-derived organic carbon drawn down from ponds into the underlying aquifers has been proposed but remains highly controversial. Here we present isotopic data from two sites with contrasting groundwater pumping histories that unequivocally demonstrate the ingress of surface pond-derived organic carbon into arsenic-containing groundwaters. We show that pond-derived organic carbon is transported to depths of up to 50 m even in an arsenic-contaminated aquifer in Cambodia thought to be minimally disturbed by groundwater pumping. In contrast, in the extensively exploited groundwaters of West Bengal, we show that pond-derived organic carbon is transported in shallow groundwater to greater depths, in excess of 100 m in the aquifer. Intensive pumping of groundwaters may potentially drive secular increases in the groundwater arsenic hazard in this region by increasing the contribution of bioavailable pond-derived dissolved organic carbon drawn into these aquifer systems and transporting it to greater depths than would operate under natural flow conditions.

Mount Pinatubo, Inflammatory Cytokines, and the Immunological Ecology of Aeta Hunter-Gatherers

Early growth cessation and reproduction are predicted to maximize fitness under conditions of high adult mortality, factors that could explain the pygmy phenotype of many rainforest hunter-gatherers. This life-history hypothesis is elegant but contentious in part because it lacks a clear biological mechanism. One mechanism stems from the field of human immunological ecology and the concept of inflammation "memory" across the life cycle and into subsequent generations. Maternal exposures to disease can influence immunological cues present in breast milk; because maternal provisioning via lactation occurs during critical periods of development, it is plausible that these cues can also mediate early growth cessation and small body size. Such epigenetic hypotheses are difficult to test, but the concept of developmental programming is attractive because it could explain how the stature of a population can change over time, in terms of both secular increases and rapid intergenerational decreases. Here we explore this concept by focusing on the Aeta, a population of former hunter-gatherers, and the Ilocano, a population of rice farmers. We predicted that Aeta mothers would produce breast milk with higher concentrations of four bioactive factors due to high infectious burdens. Further, we predicted that the concentrations of these factors would be highest in the cohort of women born in the early 1990s, when exposure to infectious disease was acute following the eruption of Mount Pinatubo in June 1991. We analyzed levels of adiponectin, C-reactive protein, and epidermal growth factor in the milk of 24 Aeta and 31 Ilocano women and found no detectable differences, whereas levels of transforming growth factor-?2 were elevated among the Aeta, particularly as a function of maternal age. We found no difference between cohorts divided by the volcanic eruption (n = 43 born before, n = 12 born after). We discuss the implications of our findings for the terminal investment hypothesis and we suggest that the historical ecology of the Aeta is a promising model system for testing epigenetic hypotheses focused on the evolution of small body size.

Orbital period variation study of the low-mass Algol eclipsing binary AI Draconis

Orbital period changes for the Algol-type eclipsing binary AI Dra were studied based on the analysis of its observed times of light minimum. The period variation showed cyclic changes in the interval from JD.≈2436000 to JD.≈2447500 and a secular period increase rate (dP/dt=2.44×10−7d/year) starting from JD.≈2448500 up to 2455262, in a time scale equals to 5×106year.

Semiconvection: numerical simulations

A grid of numerical simulations of double-diffusive convection is presented for the astrophysical case where viscosity (Prandtl number Pr) and solute diffusivity (Lewis number Le) are much smaller than the thermal diffusivity. As in laboratory and geophysical cases convection takes place in a layered form. The proper translation between subsonic flows in a stellar interior and an incompressible (Boussinesq) fluid is given, and the validity of the Boussinesq approximation for the semiconvection problem is checked by comparison with fully compressible simulations. The predictions of a simplified theory of mixing in semiconvection given in a companion paper are tested against the numerical results, and used to extrapolate these to astrophysical conditions. The predicted effective He-diffusion coefficient is nearly independent of the double-diffusive layering thickness $d$. For a fiducial main sequence model (15 $M_\odot$) the inferred mixing time scale is of the order $10^{10}$ yr. An estimate for the secular increase of $d$ during the semiconvective phase is given. It can potentially reach a significant fraction of a pressure scale height.

The rise in female participation in Colombia: Fertility, marital status or education?

Colombia has experienced a secular increase in the labor participation of urban women, going from nearly 47% in 1984 to 65% in 2006. We decompose the evolution of participation into changes in the composition of the population and changes in the participation rates by groups (defined according to the variables that appear most relevant: educational attainment, fertility and marital status). The increase in participation is driven by the increase in the participation rate of married or cohabiting women and women with low educational attainment. Fertility status appears to be less important. Changes in the population composition by educational attainment are also relevant in explaining the increase in participation. However, changes in composition by marital status or fertility are second order effects.

Increase of the mean Sun–Earth distance caused by a secular mass accumulation

Based on many planetary observations between the years 1971 and 2003, Krasinsky and Brumberg (Celest. Mech. Dyn. Astron. 90:267–288, 2004) have estimated a rate of increase in the mean Sun-Earth distance of (15±4) m per century. Together with other anomalous observations in the solar system, this increase appears to be unexplained (Lammerzahl et al. in Astrophys. Space Sci. Lib., vol. 349, pp. 75–101, 2008). We explain these findings by invoking a recently proposed gravitational impact model (Wilhelm et al. in Astrophys. Space Sci. 343:135–144, 2013) that implies a secular mass increase of all massive bodies. This allows us to formulate a quantitative understanding of the effect within the parameter range of the model with a mass accumulation rate of the Sun of (6.4±1.7)×1010 kg s−1.

Who discovered the Flynn effect? A review of early studies of the secular increase of intelligence

Flynn has been credited with having discovered the increase in IQs that has been reported in a number of countries during most of the twentieth century and that has come to be known as “the Flynn effect”. This paper documents and discusses a number of reports of increases in IQs that were published from 1936 onwards before the phenomenon was rediscovered by Flynn (1984, 1987). These early reports showed that the Flynn effect is fully present in pre-school children, does not increase during the school age years, and is greater for non-verbal abilities than for verbal abilities.

Authors' response to 'Limitless longevity': The contribution of rectangularization to the secular increase in life expectancy: an empirical study

Related article : Letter to the Editor: Karin Modig, Sven Drefahl, and Anders Ahlbon.Limitless longevity: Comment on the Contribution of rectangularization to the secular increase of life expectancy

Limitless longevity: Comment on the Contribution of rectangularization to the secular increase of life expectancy

Limitless longevity: Comment on the Contribution of rectangularization to the secular increase of life expectancy

Family Income and Education Were Related with 30-Year Time Trends in Dietary and Meal Behaviors of American Children and Adolescents

AbstractRecent survey data reveal the persistence of long-acknowledged socioeconomic status (SES) differentials in the prevalence of obesity in U.S. children and adolescents. We examined 30-y changes in the association of dietary and meal behaviors with family income and education to understand the possible contribution of these trends to SES trends in obesity rates in 2- to 19-y-old Americans. We used dietary and SES data for 2- to 19-y olds from the NHANES 1971–1974 to 2003–2008 (n = 39,822). The secular changes in the independent association of family income and education with 24-h dietary behaviors [energy intake (kcal), amount of foods and beverages (g), percent energy from all beverages and from nutritive beverages, and energy density of foods] and 24-h meal behaviors [number of eating occasions, energy from snack episodes (%), and mention of breakfast] were examined using multivariable regression methods. The secular increase in energy intake and food and beverage amount was significant in the lowest family SES categories. The positive association of family income and education with intakes of energy, food amounts, and beverage energy, noted in 1971–1974 or 1976–1980, was not observed in later surveys. There was an age gradient in changes in most diet and SES associations over time, with largest adverse changes in 12- to 19-y olds. Higher education was associated with lower energy from snack episodes, breakfast skipping, and energy density of foods and these associations did not change over time. Overall, these results suggest both income and education differentials in secular increases in food amounts and energy intakes.

A secular increase in BMD in Chinese women

Population-based studies have revealed a decline in the incidence of age-adjusted hip fractures in southern Chinese women during the past decade. To determine whether there was a secular change in population characteristics that accounted for this decline, we compared the bone mineral density (BMD) and lifestyle habits of two cohorts of women who were more than 50 years of age and who were recruited from 1995 to 2000 and 2005 to 2010. The BMD levels in the 2005-2010 cohort were significantly higher at the spine and hip and ranged from 3.6 to 17.8% among the different age groups. Additionally, a significantly lower prevalence of subjects with osteoporosis and osteopenia was observed. Longer reproductive years, higher levels of physical activity, higher estradiol and 25(OH) vitamin D levels, and lower alkaline phosphatase levels were found in the 2005-2010 cohort. After adjusting for bone-determining factors, significant differences were detected in the BMD levels at the lumbar spine, femoral neck, and total hip (4.17, 9.02, and 9.34%, respectively) in women >50 years of age but not in women ≤50 years of age. The secular increase in BMD and healthier lifestyles most likely led to the decline in the incidence of age-adjusted fractures.

Who discovered the Flynn Effect? A review of early studies of the secular increase of intelligence

Flynn has been credited with having discovered the increase in IQs that have been reported in a number of countries during most of the twentieth century and that have come to be known as “the Flynn effect”. This paper documents and discusses a number of reports of increases in IQs that were published from 1936 onwards before the phenomenon was rediscovered by Flynn (1984, 1987). These early reports showed that the Flynn effect is fully present in pre-school children, does not increase during the school age years, and is greater for non-verbal abilities than for verbal abilities.

Cohorts based on decade of death: No evidence for secular trends favoring later cohorts in cognitive aging and terminal decline in the AHEAD study.

Studies of birth-year cohorts examined over the same age range often report secular trends favoring later-born cohorts, who are cognitively fitter and show less steep cognitive declines than earlier-born cohorts. However, there is initial evidence that those advantages of later-born cohorts do not carry into the last years of life, suggesting that pervasive mortality-related processes minimize differences that were apparent earlier in life. Elaborating this work from an alternative perspective on cohort differences, we compared rates of cognitive aging and terminal decline in episodic memory between cohorts based on the year participants had died, earlier (between 1993 and 1999) or later in historical time (between 2000 and 2010). Specifically, we compared trajectories of cognitive decline in 2 death-year cohorts of participants in the Asset and Health Dynamics Among the Oldest Old study that were matched on age at death and education and controlled for a variety of additional covariates. Results revealed little evidence of secular trends favoring later cohorts. To the contrary, the cohort that died in the 2000s showed a less favorable trajectory of age-related memory decline than the cohort that died in the 1990s. In examinations of change in relation to time to death, the cohort dying in the 2000s experienced even steeper terminal declines than the cohort dying in the 1990s. We suggest that secular increases in "manufacturing" survival may exacerbate age- and mortality-related cognitive declines among the oldest old.

Explanation of the anomalous secular increase of the moon orbit eccentricity by the new theory of gravitation (NTG).

Explanation of the anomalous secular increase of the moon orbit eccentricity by the new theory of gravitation (NTG).

BINARITY AND PULSATION IN ALGOL-TYPE BINARY SYSTEM SX DRACONIS

Photometric observations of SX Dra were carried out to determine the properties of the components and pulsational characteristics of the more massive pulsational component. Physical parameters of the component stars were obtained by modeling B and V light curves using the Wilson-Devinney code. Results indicate that SX Dra is a semi-detached system with the secondary component filling its Roche lobe. The O–C data showed parabolic and sinusoidal variation. Cyclic variation in the O–C diagram could be the result of the possible magnetic activity of the secondary component instead of the third body. The secular increase in the orbital period of the system can be interpreted as being the result of mass transfer from the secondary component to the primary one at a rate of 2.1 × 10–7 M ☉ yr–1. Results of a time-series analysis performed after removing binary effects indicated that the hot component shows δ Scuti light variations with pulsational periods of 63 and 73 minutes. Spherical harmonic degrees (l) were determined to be 3 for the first frequency and 1-2 for the second frequency.

Growing up before growing out: secular trends in height, weight and obesity in 5–6-year-old children born between 1970 and 2006

BackgroundThis was a whole-population study of height, weight and obesity prevalence in 5–6-year-old children born between 1970 and 2006 in the Grampian region, north east Scotland.MethodsHeights and weights collected as...

Secular trends on traditional ecological knowledge: An analysis of changes in different domains of knowledge among Tsimane' men

Empirical research provides contradictory evidence of the loss of traditional ecological knowledge across societies. Researchers have argued that culture, methodological differences, and site-specific conditions are responsible for such contradictory evidences. We advance and test a third explanation: the adaptive nature of traditional ecological knowledge systems. Specifically, we test whether different domains of traditional ecological knowledge experience different secular changes and analyze trends in the context of other changes in livelihoods. We use data collected among 651 Tsimane' men (Bolivian Amazon). Our findings indicate that different domains of knowledge follow different secular trends. Among the domains of knowledge analyzed, medicinal knowledge and wild edible knowledge appear as the most vulnerable; canoe building knowledge and firewood knowledge seem to remain constant across generations; whereas house building knowledge seems to experience a slight secular increase. Our analysis reflects on the adaptive nature of traditional ecological knowledge, highlighting how changes in this knowledge system respond to the particular needs of a society in a given point of time.

Mount Pinatubo, Inflammatory Cytokines, and the Immunological Ecology of Aeta Hunter-Gatherers

Early growth cessation and reproduction are predicted to maximize fitness under conditions of high adult mortality, factors that could explain the pygmy phenotype of many rainforest hunter-gatherers. This life-history hypothesis is elegant but contentious in part because it lacks a clear biological mechanism. One mechanism stems from the field of human immunological ecology and the concept of inflammation “memory” across the life cycle and into subsequent generations. Maternal exposures to disease can influence immunological cues present in breast milk; because maternal provisioning via lactation occurs during critical periods of development, it is plausible that these cues can also mediate early growth cessation and small body size. Such epigenetic hypotheses are difficult to test, but the concept of developmental programming is attractive because it could explain how the stature of a population can change over time, in terms of both secular increases and rapid intergenerational decreases. Here we explore this concept by focusing on the Aeta, a population of former hunter-gatherers, and the Ilocano, a population of rice farmers. We predicted that Aeta mothers would produce breast milk with higher concentrations of four bioactive factors due to high infectious burdens. Further, we predicted that the concentrations of these factors would be highest in the cohort of women born in the early 1990s, when exposure to infectious disease was acute following the eruption of Mount Pinatubo in June 1991. We analyzed levels of adiponectin, C-reactive protein, and epidermal growth factor in the milk of 24 Aeta and 31 Ilocano women and found no detectable differences, whereas levels of transforming growth factor-β2 were elevated among the Aeta, particularly as a function of maternal age. We found no difference between cohorts divided by the volcanic eruption (n = 43 born before, n = 12 born after). We discuss the implications of our findings for the terminal investment hypothesis and we suggest that the historical ecology of the Aeta is a promising model system for testing epigenetic hypotheses focused on the evolution of small body size.

The US Labor Market in 2030: A Scenario Based on Current Trends in Supply and Demand

Three fundamental forces have shaped labor markets over the last 50 years: the secular increase in the returns to education, educational upgrading, and the integration of large numbers of women into the workforce. We modify the Katz and Murphy (1992) framework to predict the structure of the labor market in 2030. Even though the share of educated females in the workforce will grow rapidly, the supply response will not suffice to offset the trend in demand towards skilled, female labor. Wage growth over the next 20 years will continue to favor college educated workers and in particular college educated females.