Secular Changes Research Articles

Depositional and diagenetic constraints on the quality of shale‐gas reservoirs: A case study from the Late Palaeocene of the Potwar Basin (Pakistan, Eastern Tethys)

Unconventional shale‐gas reservoir assessment concurs numerous exploration challenges, often related to their complex lithology, which reflects secular changes in depositional environment(s) as well as spatially variable diagenetic overprinting. This study combines a range of methods (sedimentological, petrographical, CL‐microscopy, X‐ray diffraction, TOC (total organic carbon), TON (total organic nitrogen) and δ13Corg and δ15Norg stable isotopes) to address the controls of lithofacies, palaeo‐depositional environment(s) and diagenesis on the shale‐gas reservoir potential of the Late Palaeocene Patala Formation in the Potwar Basin of Pakistan. This formation records sediment accumulation in a shallow, mixed siliciclastic‐carbonate shelf environment. Sedimentological and X‐ray diffraction (XRD) analyses show that the formation is primarily composed of an alternation of carbonaceous, siliceous, calcareous and argillaceous mudstone lithofacies. Detrital assemblages, including grains of quartz, apatite, calcite, chlorite, as well as organic matter (OM) and clay minerals with auxiliary (authigenic) pyrite, dominate the formation. High terrigenous influx is represented by the abundance of siliciclastics and terrigenous OM. The δ13Corg and δ15Norg proxies reflect dysoxic to anoxic palaeo‐environmental conditions, which promoted preservation of mixed marine and terrigenous OM, a setting considered to be indicative for high shale‐gas potential. The organic‐rich siliceous and carbonaceous mudstone lithofacies are considered to be the most prospective intervals, while calcareous and argillaceous mudstones are considered least promising in terms of reservoir quality. Spatially variable eo‐, meso‐ and telo‐diagenetic features such as compaction, cementation, stylolitization, dissolution and re‐precipitation are superimposed upon the depositional fabric, which locally affected the reservoir quality of the Patala Formation. The results of this study strongly suggest that the organic‐ and quartz‐rich mudstone lithofacies constitute “sweet spots” whose occurrence in space and time may be traced to design a strategy for shale‐gas exploration in the Potwar Basin of Pakistan and in analogous settings elsewhere.

SECULAR CHANGES IN MAIN ANTHROPOMETRIC INDICATORS FOR THE EVALUATION OF THE PHYSICAL DEVELOPMENT OF CHILDREN AT THE AGE BETWEEN 3-6 YEARS FROM SMOLYAN REGION, BULGARIA (1996/98- 2017/19)

The purpose of the present study is to investigate the secular changes in the body height, weight, chest and head circumferences in preschool children (3-6 years) from the Smolyan region, Bulgaria, during the past 20 years. Material and methods. A transversal anthropometric study of 330 clinically healthy children, aged between 3 to 6 years from Smolyan region, Bulgaria, was performed in the period 2017-2019 (Sample B). For the aims of the analysis, earlier anthropometric data, collected by the author for 406 preschool children from the Smolyan region, aged between 3-6 years, transversally studied in the period 1996-1998 (Sample A) were also used. The height, weight, chest and head circumference have been measured for each child, as per Martin-Saller's methods. The data have been processed through the statistical package Statistica 12.0 by using analysis of variance. The Student's T-test was used a check the significance. Results. Our results show the significant increase of height and weight of boys at the age of 3 and 5 years and the weight of girls at the age of 3 and 6 years. A statistically reliable reduction in the chest and head circumferences among boys at the age of 6 years. On the grounds of these negative secular changes, the modern girls at the age of 3 years have a reliably larger chest and head circumference in comparison to their peers 20 years ago. At the same time the girls at the age of 5 years are with chest circumference, which is almost 2 cm smaller in comparison to their peers. Conclusions. Our results once again show the multidimentional character of the secular changes, which are presented, to various extents, in the various morphological systems of the body during the different stages of the ontogenesis and are different for the two genders.

Period Changes of 14,127 Contact Eclipsing Binaries in the Galactic Bulge

Abstract We present the orbital-period variations of 14,127 contact eclipsing binaries (CEBs) based on the OGLE-III&IV observations in the Galactic bulge. New times of minimum lights for the CEBs were derived by binary modeling for the full seasonal light curves, which were made from survey observations at an interval of 1 yr. The orbital-period changes of the systems were classified based on the statistical inference, multiple-hypothesis testing error measure, and visual inspection of the eclipse-timing diagrams. As the results, we identified 13,716 CEBs with a parabola, 307 CEBs with a sinusoid, and 104 CEBs with the two variations. The period distributions of the inner close binaries and the outer companions were in the ranges of 0.235–0.990 days and 5.0–14.0 yr, respectively. In our sample of 13,820 CEBs showing a parabolic variation, the highest decreasing and increasing period rates were determined to be P ̇ = − 1.38 ± 0.06 × 10 − 5 day yr−1 for OGLE-BLG-ECL-169991 and P ̇ = + 8.99 ± 0.44 × 10 − 6 day yr−1 for OGLE-BLG-ECL-189805, respectively. The secular period change rates were distributed almost symmetrically around zero, and most of them lie within P ̇ = ± 5.0 × 10 − 6 day yr−1.

Trends in the Prevalence of Obesity and Its Phenotypes Based on the Korea National Health and Nutrition Examination Survey from 2007 to 2017 in Korea.

This study used data from the Korea National Health and Nutrition Examination Survey IV–VII from 2007 to identify the prevalence of obesity and its phenotypes (metabolically unhealthy obesity [MUO] and metabolically healthy obesity [MHO]) and their secular changes. The prevalence of obesity in Korea increased with significant secular changes observed (β=0.326, P trend <0.01) between 2007 and 2017, and especially in men (β=0.682, P trend <0.001) but not in women. The changes in the prevalence of obesity during the study period were different between men and women (P=0.001). The prevalence of MUO significantly increased only in men (β=0.565, P trend <0.01), while that of MHO increased only in women (β=0.179, P<0.05), especially in the younger age group (β=0.308, P<0.01).

Magma and Mineral Composition Response to Increasing Slab-Derived Fluid Flux: Nevado de Longaví Volcano, Southern Chilean Andes

Nevado de Longaví volcano (NLV), in the Southern-Central Chilean Andes, has erupted during the Holocene magmas with compositions that are in several ways atypical for the region. These characteristics include elevated La/Yb ratios in evolved magmas, in an area of only moderately thick crust, coupled with low concentrations of K, Th, and other incompatible elements and elevated ratios of fluid-mobile (B, Cs, Li, Sb) to fluid-immobile elements. Samples have an unusual mafic mineralogy dominated by amphibole. The petrology of the Holocene products of NLV have been related to the influence of an oceanic transform fault (Mocha Fracture Zone; MFZ) that supplies the mantle wedge with unusually high amounts of fluids via dehydration of serpentinite bodies hosted by the subducted oceanic lithosphere. Because the trace of this transform fault is oblique to the convergence vector, its position along the arc has varied through time, as has the magnitude of its influence on the nature of the magmas erupted at NLV. The whole-rock and mineral chemistry of volcanic products from NLV, tied to a simplified stratigraphy, documents the secular changes in the magmatic system as the oceanic fault approached its current position. Magmas erupted ∼1–0.6 Ma are relatively low in water (as inferred from mineralogy and chemical proxies) and reduced (NNO-1 to NNO+0.5), and are similar to compositions found in neighboring volcanoes. From 0.25 Ma to the present, magmas are water-rich and oxidized (NNO-0.5 to NNO+1.7). In the intervening 0.6–0.25 Ma, mafic magmatism acquired a transient crustal component, which we identify as subducted sediment melts, on the basis of radiogenic isotopes and Pb, Th, and U abundances. Fluids released from serpentinite in the fracture zone were rich in Li, B, Sb, Cs and Ba, but not in K, Th, U and Sr. The fluid addition led to enhanced melting, particularly hydrous magmas that stabilized amphibole early during fractionation, higher oxygen fugacities, and distinctive chemical compositions.

Increased Variability of Biomass Burning Emissions in CMIP6 Amplifies Hydrologic Cycle in the CESM2 Large Ensemble

AbstractHistorical simulations performed for the Coupled Model Intercomparison Project Phase 6 used biomass burning emissions between 1997 and 2014 containing higher spatial and temporal variability compared to emission inventories specified for earlier years, and compared to emissions used in previous (e.g., CMIP5) simulation intercomparisons. Using the Community Earth System Model version 2 Large Ensemble, we show this increased biomass burning emissions variability leads to amplification of the hydrologic cycle poleward of 40°N. Notably, the high variability of biomass burning emissions leads to increased latent heat fluxes, column‐integrated precipitable water, and precipitation. Greater ocean heat uptake, weaker meridional energy transport from the tropics, greater atmospheric shortwave and longwave absorption, and lower relative humidity act to moderate this hydrologic cycle amplification. Our results suggest it is not only the secular changes (on multidecadal timescales) in biomass burning emissions that impact the hydrologic cycle, but also the shorter timescale variability in emissions.

Rf-induced heating dynamics of noncrystallized trapped ions

We investigate the energy dynamics of noncrystallized (melted) ions, confined in a Paul trap. The nonperiodic Coulomb interaction experienced by melted ions forms a medium for nonconservative energy transfer from the radio-frequency (rf) field to the ions, a process known as rf heating. We study rf heating by analyzing numerical simulations of noncrystallized ion motion in Paul trap potentials, in which the energy of the ions' secular motion changes at discrete intervals, corresponding to ion-ion collisions. The analysis of these collisions is used as a basis to derive a simplified model of rf heating energy dynamics, from which we conclude that the rf heating rate is predominantly dependent on the rf field strength. We confirm the predictability of the model experimentally: Two trapped $^{40}\mathrm{Ca}^{+}$ ions are deterministically driven to melt, and their fluorescence rate is used to infer the ions' energy. Under these experimental conditions, we investigate which Doppler cooling parameters are required for efficient recrystallization, and compare our results to simulations.

Homogeneous transit timing analyses of 10 exoplanet systems

ABSTRACT We study the transit timings of 10 exoplanets in order to investigate potential transit timing variations in them. We model their available ground-based light curves, some presented here and others taken from the literature, and homogeneously measure the mid-transit times. We statistically compare our results with published values and find that the measurement errors agree. However, in terms of recovering the possible frequencies, homogeneous sets can be found to be more useful, of which no statistically relevant example has been found for the planets in our study. We corrected the ephemeris information of all 10 planets we studied and provide these most precise light elements as references for future transit observations with space-borne and ground-based instruments. We found no evidence for secular or periodic changes in the orbital periods of the planets in our sample, including the ultra-short period WASP-103 b, whose orbit is expected to decay on an observable time-scale. Therefore, we derive the lower limits for the reduced tidal quality factors (Q$^{\prime }_{\star }$) for the host stars based on best-fitting quadratic functions to their timing data. We also present a global model of all available data for WASP-74 b, which has a Gaia parallax-based distance value ∼25 per cent larger than the published value.

Fertility Responses to Schooling Costs: Evidence from Uganda’s Universal Primary Education Policy

There is some evidence that access to schooling reduces fertility along the intensive margin in developing countries, but the transmission channels are not well understood; most education interventions impact financial costs, access, and school quality. We isolate the specific effect of child school fees on maternal fertility by studying a 1997 schooling reform in Uganda, in which the government abolished elementary school fees for up to four children per household. Families with more school-aged children were required to pay fees for the additional ones. We demonstrate that eligibility limits reduced births: women with more than four children in 1997 were 4.2 percentage points less likely to give birth to an additional child in the subsequent two years. We provide evidence that this result is driven by UPE eligibility limits, not by other factors associated with the policy or other secular changes. Fertility effects are persistent over time and survive the lifting of the eligibility limit in 2003. The policy is also associated with a temporary reduction in the desired fertility, with mothers preferring having four children or fewer during the policy period than before.

Impact of FDA label change on immunotherapy for metastatic urothelial cancer (mUC) and subsequent changes in mortality.

459 Background: In May 2017, atezolizumab and pembrolizumab (IO) received accelerated approval for first-line treatment of cisplatin-ineligible patients with mUC, irrespective of PDL1 test status. In June 2018, the FDA and EMA restricted IO to cisplatin-ineligible patients with PDL1 positive tumors based on early review of data from confirmatory trials which suggested decreased overall survival in patients with PDL1 negative tumors treated with IO. We assessed the impact of the FDA label change on clinical outcomes of mUC patients in routine care. Methods: We conducted a controlled interrupted time series analysis using the US Flatiron Health electronic health record-derived de-identified database. The study sample included patients from 280 cancer clinics nationwide diagnosed with mUC and compared patients potentially impacted by the label change (cisplatin ineligible patients initiating first-line IO or carboplatin-based chemotherapy) to a comparator group who would have been unaffected by the label change (patients initiating first-line cisplatin-based chemotherapy) from 01 April 2017 to 17 May 2018 (pre-label change) and 20 June 2018 to 01 March 2020 (post-label change), excluding a 30-day wash out period encompassing the time-period between the initial FDA safety alert (18 May 2018) and the official FDA label change (19 June 2018). We used Cox regression to estimate adjusted pre-/post-label change related mortality differences in patients receiving carboplatin-chemotherapy or IO, accounting for secular changes in survival through comparison with the cisplatin comparator group. Results: The study included 829 patients with mUC initiating treatment in the pre-label change period (582 IO or carboplatin, 247 cisplatin) and 1,184 patients in the post-label change period (849 IO or carboplatin, 336 cisplatin), respectively. The use of IO, carboplatin, and cisplatin was similar across time-periods (pre-label change: 44.4%, 25.8%, and 29.8%; post-label change: 48%, 23.6%, 28.4%); while PD-L1 testing increased (6.6% to 28.1%). In adjusted models, there were no differences in survival in any of the groups following the FDA label change policy (table). Conclusions: The U.S. FDA label restriction on first-line immunotherapy was associated with increased PD-L1 testing but was not associated with changes in treatment patterns or improved mortality among patients with mUC.[Table: see text]

Secular trends in childhood pain and comorbid psychiatric symptoms: a population-based study

PurposePain symptoms are common in childhood. They often lead to functional impairment and co-occur with psychiatric difficulties. Although children’s lives have undergone enormous changes in recent decades, long-term data on changes in pain symptoms, and in comorbid psychiatric difficulties, is lacking. This knowledge is crucial, as co-occurring psychiatric symptoms are significant predictors of long-term outcome for children who suffer from pain. The main purpose of the present study was to explore secular changes in comorbid pain and psychiatric symptoms.MethodsFour population-based, cross-sectional surveys of 8–9-year-old children were conducted in Southwest Finland in 1989, 1999, 2005, and 2013. Identical methodologies and questionnaire-based measures were used each study year. Participation ranged from 891 to 986 over the study period. The children were asked about the frequency of headache, abdominal pain, and other pains. Children, their parents, and teachers provided information on the child’s psychiatric difficulties, including internalizing and externalizing symptoms.ResultsThe cumulative odds ratios and 95% confidence intervals for the overall prevalence of pain symptoms increased among both genders from 1989 to 2013 and ranged from 1.4 (1.03–1.8) for other pains to 2.4 (1.7–3.3) for abdominal pain. Comorbid internalizing symptoms increased among girls with odd ratios and 95% CIs of 1.8 (1.03–3.1) for children with any kind of pain, and 3.0 (1.4–6.2) for children with headache. No changes were found among boys.ConclusionOverall pain symptoms doubled in both genders, but the most novel finding was that comorbid emotional difficulties tripled among girls who reported headaches. Further research is needed to confirm, and explain, these findings.

THE CHANGING STRUCTURE OF GOVERNMENT CONSUMPTION SPENDING

AbstractWe document a secular change in the structure of government consumption spending: Over time the government purchases relatively more private‐sector goods, and relies less on its own production of value added. This process alters the transmission of fiscal policy, by dampening the response of hours, public value added, and the labor share to government spending shocks, while leaving the response of total output unchanged. We rationalize these facts in a general equilibrium model where a decline of the public‐sector relative productivity drives the changing structure of government spending, which in turn modifies the transmission mechanism of government spending shocks.

Mapping intrashell variation in Mg/Ca of brachiopods to external growth lines: Mg enrichment corresponds to seasonal growth slowdown

Determining secular changes in seawater temperature and Mg/Ca ratio is of high importance in paleooceanographic, paleoenvironmental and paleoecological studies. On the one hand, intra-shell variation in Mg/Ca in brachiopod shells is used to reconstruct historical changes in temperature and in seasonality. On the other hand, intra-shell analyses show a weak relationship between Mg/Ca and δ18O, but a positive correlation between Mg/Ca and Sr/Ca, and an increase of Mg/Ca at growth lines, indicating that Mg/Ca does not simply track seawater temperature alone. Internal growth lines are rarely visible in brachiopod shells, and the relation between growth lines that mark growth slowdown or cessation and Mg/Ca fluctuation is thus not properly understood. Here, using four species of extant brachiopods from the NE Pacific and the SW Pacific, from environments with low seasonality in seawater temperature (<5 °C), and two species of Late Triassic brachiopods (Western Carpathians), we measure intra-shell ontogenetic variation in Mg/Ca, S/Ca and Sr/Ca with laser ablation ICP-MS and electron microprobe. In contrast to previous studies, we map variation in Mg, S, and Sr to external growth lines. We find that, first, zones of Mg/Ca enrichment in the secondary layer form 10–50 μm-thick discrete bands or clusters of micrometric bands that consistently terminate at major external, predominantly annual growth lines that are associated with distinct notches that correspond to mantle retractions in most species. These bands generate distinct peaks in Mg/Ca that stand above low, more uniformly distributed background Mg/Ca values along laser-ablation and microprobe transects. The magnitude of Mg/Ca in these bands is comparable to Mg/Ca in the primary layer, exceeding background values of Mg/Ca in the secondary layer by 5–20 mmol/mol (by a factor of two to five). Second, Mg enrichment in discrete bands is closely associated with an increase in S concentrations in the secondary layer. Therefore, even when Mg and S uptake is expected to be highest under fast precipitation rate, these empirical observations show that Mg and S enrichment occur in the zones that were precipitated at times of a significant growth reduction (e.g., in cold-temperate brachiopods studied here during winters when primary productivity is low). The mechanisms for this paradox are unclear but can be related to uptake of Mg by amorphous calcium carbonate (ACC) to delay the transformation of ACC to calcite during the formation of growth lines. Therefore, intra-shell variation in Mg/Ca in brachiopods with major growth lines is primarily determined by seasonal decline or cessation in shell growth and not by seasonal changes in seawater temperature.

Secular growth trend characteristics of the body structure in Hungarian athlete boys.

The aim of the present study was to get more knowledge of the nature of athlete boy's secular body changes and to differentiate it from the individual acceleration. A positive secular trend was supposed in athlete youth similar to normal population, but with different extent because of the sport selection. In this study some specific trend characteristics of athlete (basketball player) boys between the 1990th and 2010th are analyzed and compared to that of the reference values of the Hungarian National Growth Study I and II (HNGS I - 1980's, Eiben et al. 1991; HNGS II - 2003-2006, Bodzsár & Zsákai 2007). The individual data were collected in Budapest (capital) basketball club boys aged 10-15 years (N = 1376). Body measurements were taken by the first author by the request of coaches and parents. Secular trend was characterized by the changes in some of the measured body parameters by three birth cohorts. The secular changes followed a positive trend, though the traditional decade analyses the variables did not follow a balanced, proportional manner of change. The largest difference in body height occurred in 12-years of age, with a total of +8.27 cm height difference between Cohort III and I and +9.31 kg total difference in body mass at the same age, respectively. Some differences in the tendentious changes occurred between the age groups, characteristic shift of the fat content and the trunk/extremity fat ratio increase toward the younger age, and more excessive increase in BMI were found. Though it could be expected to have favourable body composition in young athletes, nowadays some unfavourable changes in the secular growth trend of body structure have been occurred. One explanation could be the less active leisure time spent. Our results can provide more practical information for coaches to enrich their professional attitude towards a better understanding how to choose and modify training methods during the varied growth and developmental process of young athletes.

Weight status of rural school youth in Poland: secular change 1986-2016.

The objective of this study was to evaluate secular changes in the Body Mass Index (BMI) and weight status of rural children and adolescents in west-central Poland across decennial surveys spanning 1986 and 2016. Participants were 8,677 boys and girls 7-15 years attending schools in 10 rural communities in 1986, 1996, 2006, and 2016. Heights and weights were measured; BMIs were calculated. Weight status was classified using International Obesity Task Force (IOTF) criteria. The sample was partitioned into three age groups (7-9, 10-12, 13-15 years) for analysis of secular change in the BMI using sex-specific analysis of covariance (ANCOVA) with age and age2 as covariates, and for comparison of the prevalence of mild, moderate and severe thinness and of overweight and obesity. BMIs increased, on average, across the four surveys, but differences between adjacent surveys varied. Prevalence of severe and moderate thinness was low in both sexes, while mild thinness tended to decline over time, more so among girls. Overweight and obesity increased over time, especially in 2006 and 2016 compared to 1986 and 1996. In conclusion, secular changes in the BMI between 1986 and 2016 were significant. Age-adjusted mean BMIs suggested a gradient, 2016 > 2006 > 1996 > 1986, except in girls 13-15 years. However, changes across the decennial surveys varied. The observed changes in overweight and obesity between 1986 and 2016 were consistent with studies in Poland spanning the past two generations.

Somatotypological structure of university students in the sex groups of equal body heights.

Among the numerous publications on sexual dimorphism as affected by body build, few deal with the somatotype of men and women of the same height. The aim of the study was to determine the share of endomorphy, mesomorphy, and ectomorphy among men and women in different height categories and to determine whether the size of individual components differs between the sexes within the same height category. The research was carried out over the period of 2005-2015 on a cohort of 1,911 individuals, 625 men and 1,286 women, aged 18-25. Somatic measurements were performed according to the currently accepted technique as described by Martin and Saller. Using the results and the Heath-Carter method, the shares of endomorphy, mesomorphy, and ectomorphy were calculated. Multivariate analysis of variance was used to assess the relation between sex, individual height category and endomorphy, mesomorphy, and ectomorphy. Relationships between endomorphy, mesomorphy, ectomorphy and height were estimated using Pearson correlation and linear regression. In women's body build, regardless of body height, endomorphy prevails, with smaller shares of ectomorphy and mesomorphy while in men's body build mesomorphy and ectomorphy dominate. The analysis of forecasts (using linear regression equations) confirms that mesomorphy and endomorphy decrease in men and women as their height increases. The findings will be used to analyse secular changes in the evolution of male and female body build type over a longer period - which will show increasing or fading dimorphic differences.

Abstract TMP53: Nationwide Secular Changes In Severity And Outcome Of Ischemic And Hemorrhagic Strokes: A 20-Year Analysis From Japan Stroke Data Bank Involving 183,082 Patients

Introduction: The Japan Stroke Data Bank (JSDB) is a 20-year long ongoing hospital-based multicenter prospective registry of hospitalized patients with acute stroke/TIA based on a web database from 130 stroke centers distributed evenly over Japan. Hypothesis: Secular changes in the severity and functional outcome of stroke patients would be clarified by long-lasting hospital-based registries. Methods: Patients registered in JSDB within 7 days after stroke onset from Jan 2000 through Dec 2019 were studied. The initial severity was assessed by the NIHSS for ischemic stroke (IS) and intracerebral hemorrhage (ICH) and by the WFNS grading for subarachnoid hemorrhage (SAH). Outcomes at hospital discharge was assessed by the mRS. Results: Of a total 183,082 stroke patients, 135,268 (women in 39.8%) developed IS, 36,014 (women in 42.7%) developed ICH, and 11,800 (women in 67.2%) developed SAH. Median ages at onset increased and the NIHSS and WFNS scores decreased after multivariable-adjustment in all three stroke types. Patients with favorable outcome, corresponding to the mRS 0-2, significantly increased after age-adjustment in all three IS subtypes, remained increasing after further adjustment by NIHSS and stroke history only in cardioembolic stroke (OR 1.014, 95% CI 1.008-1.020, per year), and no longer increased after further adjustment by reperfusion therapy in any subtypes. Both the frequencies of unfavorable outcome, corresponding to the mRS 5-6, and in-hospital death, significantly decreased in cardioembolic stroke (OR 0.974, 95% CI 0.968-0.980) and large-artery atherosclerosis (OR 0.975, 95% CI 0.967-0.982, both for unfavorable outcome) after multivariable-adjustment. In ICH and SAH, favorable outcome significantly decreased after multivariable-adjustment, except for SAH in men. Both the frequencies of unfavorable outcome and death after SAH significantly decreased, but those after ICH were not. These findings were generally common to both sexes when separately analyzed. Conclusions: Short-term functional outcome improved in IS patients during the past 20 years presumably partly due to development of acute reperfusion therapy. The outcome of hemorrhagic stroke patients did not clearly show the improvement during the same duration.

Worsening trends in self-rated health and correlates in Chinese adolescents in Hong Kong: a population-based panel study from 1999/2000 to 2014/15

ObjectivesTo examine the 15-year secular trends of self-rated health (SRH) and correlates in Chinese adolescents in Hong Kong.DesignA territory-wide population-based panel data study.SettingAnonymised records of the annual health examination from...

What Are We Really Estimating in Forensic Anthropological Practice, Population Affinity or Ancestry?

While American forensic anthropologists often state that they estimate ancestry, is that what they are really estimating? Although typological terminology, the oids, was replaced with continental terminology, the change was linguistic rather than substantive. The American population is comprised largely of immigrants. Genetic data suggests a high degree of admixture within American population groups. Further, data from documented skeletal collections suggest that Americans have undergone secular changes. Our paper addresses the uniqueness of the American population as compared to ancestral continental and geographic origin groups to address what it is that forensic anthropologists are really estimating, ancestry or something else? We conclude, based on uniqueness of American population groups, that what forensic anthropologists are estimating is best described as affinity, a term that indicates similarity and is not exclusively attached to definitions of race and ethnicity.

Do Maya women have the chance to improve their quality of life?

Background: Maya families suffered greatly during the henequen industry in the Yucatan, but the lives of the Maya women at the time were perhaps worse than anywhere in the world. Changes in Maya body height over the 20th century were assessed in order to show secular changes. The use of the sexual dimorphism index (SDI) allowed for the evaluation of the living conditions prevailing during the existence of the henequen haciendas to the Mexican revolution and a gradual improvement of these conditions by the end of the 20th century. Methods: In 1994, 364 men and 320 women aged 20-98 years were studied in Merida, Yucatan, Mexico. They were divided into six age groups and by sex: 20-29, 30-39, 40-49, 50-59, 60-69 and 70+ years. Stature for both sexes, and age at menarche for women were considered. SDI in stature was calculated to assess living conditions. Results: There were smaller (0.25 cm/10 years) changes in height in men than in women (0.9 cm/10 years) and no significant changes in acceleration of maturation. SDI results showed changes from 9.9 to 7.6, and this may indicate a constant, but very small improvement of living conditions. The age at menarche of women did not show statistically significant acceleration with age. Conclusions: In the colonial period of the late 19th century until the Mexican Revolution, women were worse off than men. Previous research has shown that when living conditions change, men always react faster than women, e.g. by lowering or increasing body height. Our study of the Maya population in the 20th century showed otherwise; female height increased more than male height. This may reflect that the living conditions of Maya men have not changed over the 20th century, but have improved for women.