Search

The problem of expressing cumulative detrimental effect of radiation exposure is revisited. All conventionally used and computationally complex lifetime or time-integrated risks are based on current population and health statistical data, with unknown future secular trends, that are projected far into the future. It is shown that application of conventionally used lifetime or time-integrated attributable risks (LAR, AR) should be limited to exposures under 1 Gy. More general quantities, such as excess lifetime risk (ELR) and, to a lesser extent, risk of exposure-induced death (REID), are free of dose constraints, but are even more computationally complex than LAR and AR and rely on the unknown total radiation effect on demographic and health statistical data. Appropriate assessment of time-integrated risk of a specific outcome following high-dose (more than 1 Gy) exposure requires consideration of competing risks for other radiation-attributed outcomes and the resulting ELR estimate has an essentially non-linear dose response. Limitations caused by basing conventionally applied time-integrated risks on current population and health statistical data are that they are: (a) not well suited for risk estimates for atypical groups of exposed persons not readily represented by the general population; and (b) not optimal for risk projections decades into the future due to large uncertainties in developments of the future secular trends in the population-specific disease rates. Alternative disease-specific quantities, baseline and attributable survival fractions, based on reduction of survival chances are considered here and are shown to be very useful in circumventing most aspects of these limitations. Another main quantity, named as radiation-attributed decrease of survival (RADS), is recommended here to represent cumulative radiation risk conditional on survival until a certain age. RADS, historically known in statistical literature as “cumulative risk”, is only based on the radiation-attributed hazard and is insensitive to competing risks. Therefore, RADS is eminently suitable for risk projections in emergency situations and for estimating radiation risks for persons exposed after therapeutic or interventional medical applications of radiation or in other highly atypical groups of exposed persons, such as astronauts.

We report detailed rock-magnetic and paleomagnetic results from a 27-m-long sedimentary core collected at depocenter of Lake Chapala, western Trans-Mexican Volcanic Belt. Rock-magnetic parameters point to PSD grain-size titanomagnetites as the dominant magnetic mineralogy. Observed variations, in both concentration and grain-size dependent magnetic parameters, reflect changes in the sediment supply through the studied depth, but mainly during the last half century. Stable characteristic remanent magnetization, representative of secular variation of the geomagnetic field, was retrieved after alternating field demagnetization of the natural remanent magnetization (NRM). The comparison of the obtained magnetic inclination and declination logs against the corresponding curves predicted by the Global Geomagnetic Field Model SHA.DIF.14k enables to establish an alternative sedimentation-rate independent age-depth model for the whole core, in reasonably good agreement with the one calculated using conventional radiocarbon dating. This approach works not only for Lake Chapala, but also for Lake Chalco. The correlation established between rock-magnetic parameters and paleoenvironments, based on diatom identification of representative samples within specific zones, can be considered as a novel proxy methodology. This approach opens a new perspective for new, more detailed rock-magnetic, paleomagnetic and paleoenvironmental investigations for better paleoclimatic reconstructions.

Orbital-period variations of the low-mass, semi-detached eclipsing binary RT Per are analyzed. In addition to the secular variation of the orbital period determined by the mass transfer between the components, cyclic variations are also present. Both the light-time effect and magnetic oscillations can describe the cyclic orbital-period variations of RT Per. The secular period increase can be explained by a uniform flow of matter from the lower-mass to the higher-mass component at a rate of 0.60 × 10−8M-/year, with the total angular momentum being conserved. The period variations can be represented equally accurately by either a superposition of two cyclic variations or a superposition of a secular period increase and two cyclic variations. Approximately the same parameters are derived for the lower-period (36.8 year) variations when the times of minima are fitted with a linear or a quadratic formula. For the longer-period variation, a period of 275 years and amplitude of 0.104 days are found using the linear formula, or 89 years and 0.045 days using the quadratic formula.

Nearly three decades ago paleomagnetists suggested that there existed a clear link between latitude dependence of geomagnetic paleosecular variation (PSV) and reversal frequency. Here we compare the latitude behavior of PSV for the Cretaceous Normal Superchron (CNS, 84‐126 Ma, stable normal polarity) and the preceding Early Cretaceous‐Jurassic interval (pre‐CNS, 126‐198 Ma, average reversal rate of ~4.6 Myr‐1). We find that the CNS was characterized by a strong increase in the angular dispersion of virtual geomagnetic poles (VGPs) with latitude, which is consistent with the results of earlier studies, whereas the VGP dispersion for the pre‐CNS period was nearly invariant with latitude. However, the PSV behavior for the last 5 or 10 million years (average reversal frequency of ~4.4‐4.8 Myr‐1) shows that the latitude invariance of VGP scatter cannot be considered as a characteristic feature of a frequently‐reversing field, and that a strong increase in VGP dispersion with latitude was not restricted to the long periods of stable polarity. We discuss models describing the latitude dependence of PSV and show that their parameters are not reliable proxies for reversal frequency and should not be used to make inferences about the geomagnetic field stability. During the pre‐CNS interval, the geodynamo may have operated in a regime characterized by a high degree of equatorial symmetry. In contrast, more asymmetric geodynamos suggested for 0‐10 Ma and the CNS were evidently capable of producing a very wide range of reversal frequencies. Nearly three decades ago paleomagnetists suggested that there existed a clear link between latitude dependence of geomagnetic paleosecular variation (PSV) and reversal frequency. Here we compare the latitude behavior of PSV for the Cretaceous Normal Superchron (CNS, 84–126 Ma, stable normal polarity) and the preceding Early Cretaceous‐Jurassic interval (pre‐CNS, 126–198 Ma, average reversal rate of ~4.6 Myr−1). We find that the CNS was characterized by a strong increase in the angular dispersion of virtual geomagnetic poles (VGPs) with latitude, which is consistent with the results of earlier studies, whereas the VGP dispersion for the pre‐CNS period was nearly invariant with latitude. However, the PSV behavior for the last 5 or 10 million years (average reversal frequency of ~4.4–4.8 Myr−1) shows that the latitude invariance of VGP scatter cannot be considered as a characteristic feature of a frequently reversing field and that a strong increase in VGP dispersion with latitude was not restricted to the long periods of stable polarity. We discuss models describing the latitude dependence of PSV and show that their parameters are not reliable proxies for reversal frequency and should not be used to make inferences about the geomagnetic field stability. During the pre‐CNS interval, the geodynamo may have operated in a regime characterized by a high degree of equatorial symmetry. In contrast, more asymmetric geodynamos suggested for 0–10 Ma and the CNS were evidently capable of producing a very wide range of reversal frequencies.

New paleoclimatic data from the Casa Branca salt marsh, in the southwest coast of Portugal, are compared with records previously published on the northwest coast (Caminha salt marsh) to offer a more comprehensive overview of the environmental evolution of the west Iberian margin over the last six centuries. These reconstructions are based on the foraminiferal records of two dated sediment cores retrieved from the high marsh settings and supported by geochemical-sedimentological data. Both marshes were originally formed in the AD 1300s, between the Medieval Climatic Anomaly (MCA) and the Little Ice Age (LIA), highlighting a major episode of increased sediment supply in lower estuaries linked to climate-driven changes in continental runoff. Afterwards, the two marshes evolved under different climatic regimes as reflected by their foraminiferal assemblages. The environmental conditions are characterized by higher salinity in Casa Branca (southwest), with Jadammina macrescens and Trochammina inflata as dominant species, than in Caminha (northwest), where Haplophragmoides spp. dominates. We suggest that a long-term trend of a net gain in evapotranspiration at Casa Branca inducing a higher marsh salinity baseline may explain this microfaunal contrast. Trochammina inflata seems to be a good indicator of drier periods in the studied area, connected to key events of aeolian large-dust input to the southwest coast of Portugal. The influence of the most important climate drivers was assessed, namely external (solar) and internal (North Atlantic Oscillation – NAO) forcings. Spectral and wavelet transform coherence analyses were used to detect solar footprints on foraminiferal and climate-related time series. A main significant quasi-periodicity was identified within the range of the secular Gleissberg cycle of solar activity modulating the annual NAO and regional spring-summer (simulated) temperatures after AD 1700. This stronger solar-climate coupling may be related to the known upward secular trend in the total solar irradiance after the Maunder Minimum.

Introduction. Along with the changing socio-economic status of the Polish society, differences in the nutritional statuses of children and adolescents as well as a decrease in their physical fitness are becoming apparent. The aim of the study was to determine ten-year changes in the physical fitness of girls with normal weight-to-height ratios compared to their underweight, overweight, and obese peers. Material and methods. A total of 5,760 girls aged 13-18 years were examined in 2006, and 2,669 girls were evaluated ten years later. The participants of the study underwent the Eurofit tests, and their height and weight were measured, which made it possible to calculate BMI. The subjects were divided into groups based on the recommendations of the International Obesity Task Force. Ten-year differences in physical fitness were expressed in T-scale points, and their magnitude was estimated using Student’s t-test for independent samples. The frequency of underweight and excess weight was expressed in percentages, and the size of statistical differences between the groups was evaluated using the χ2 test. Results . During the decade analysed, the prevalence of overweight and obesity in the group of girls increased and that of underweight decreased. From 2006 to 2016, there were no significant changes in the physical fitness of the girls, neither in the calculations for the entire population nor in the group with normal BMI. On the other hand, an improvement in the level of physical fitness of under-weight girls and its decrease in overweight and obese subjects were observed. However, the changes were not consistent across all Eurofit tests. Conclusion. The changes in the weight-to-height ratios and physical fitness of the girls who participated in the study show that there is a need to undertake inter-ministerial corrective actions aimed at increasing the physical activity of children and adolescents, with particular emphasis on students with excess body weight.

SUMMARY Secular variation (SV) of Earth’s internal magnetic field is the sum of two contributions, one resulting from core fluid flow and the other from magnetic diffusion. Based on the millenial diffusive timescale of global-scale structures, magnetic diffusion is widely perceived to be too weak to significantly contribute to decadal SV, and indeed is entirely neglected in the commonly adopted end-member of frozen-flux. Such an argument however lacks consideration of radially fine-scaled magnetic structures in the outermost part of the liquid core, whose diffusive timescale is much shorter. Here we consider the opposite end-member model to frozen flux, that of purely diffusive evolution associated with the total absence of fluid flow. Our work is based on a variational formulation, where we seek an optimized full-sphere initial magnetic field structure whose diffusive evolution best fits, over various time windows, a time-dependent magnetic field model. We present models that are regularized based on their magnetic energy, and consider how well they can fit the COV-OBS.x1 ensemble mean using a global error bound based on the standard deviation of the ensemble. With these regularized models, over time periods of up to 30 yr, it is possible to fit COV-OBS.x1 within one standard deviation at all times. For time windows up to 102 yr we show that our models can fit COV-OBS.x1 when adopting a time-averaged global uncertainty. Our modelling is sensitive only to magnetic structures in approximately the top 10 per cent of the liquid core, and show an increased surface area of reversed flux at depth. The diffusive models recover fundamental characteristics of field evolution including the historical westward drift, the recent acceleration of the North Magnetic Pole and reversed-flux emergence. Based on a global time-averaged residual, our diffusive models fit the evolution of the geomagnetic field comparably, and sometimes better than, frozen-flux models within short time windows.

Introduction. In retrospective studies, the effect of a given intervention is usually evaluated by using statistical tests to compare data from before and after the intervention. A problem with this approach is that the presence of underlying trends can lead to incorrect conclusions. This study aimed to develop a rigorous mathematical method to analyse temporal variation and overcome these limitations. Methods. We evaluated hip fracture outcomes (time to surgery, length of stay, and mortality) from a total of 2777 patients between April 2011 and September 2016, before and after the introduction of a dedicated hip fracture unit (HFU). We developed a novel modelling method that fits progressively more complex linear sections to the time series using least squares regression. The method was used to model the periods before implementation, after implementation, and of the whole study period, comparing goodness of fit using F-tests. Results. The proposed method offered reliable descriptions of the temporal evolution of the time series and augmented conclusions that were reached by mere group comparisons. Reductions in time to surgery, length of stay, and mortality rates that group comparisons would have credited to the hip fracture unit appeared to be due to unrelated underlying trends. Conclusion. Temporal analysis using segmented linear regression models can reveal secular trends and is a valuable tool to evaluate interventions in retrospective studies.

The northern sub-Himalayan region is the primary source of water for a large part of Pakistan. Changes in precipitation and precipitation extremes in the area may have severe impacts on water security and hydrology of Pakistan. The objective of the study is to evaluate the spatial characteristics of the trends in annual and seasonal precipitation and precipitation extremes in Gilgit Baltistan, the northern administrative territory of Pakistan surrounded by Hindu Kush, Karakoram, and the Himalayan regions. The daily gridded rainfall data (1951–2007) of Asian Precipitation—Highly Resolved Observational Data Integration Towards Evaluation (APHRODITE) at 0.25° spatial resolution was used for evaluating the trends. The novelty of the present study is the application of the modified Mann-Kendall (MMK) trend for the evaluation of the significance of precipitation trends in order to differentiate the secular trends from climate natural variability. Besides, cumulative distribution function (CDF) plots of daily rainfall for the early (1951–1980) and later (1981–2007) periods were used to show the changes in extremes. The results revealed no significant change in annual precipitation but increase in summer rainfall in the range of 0.25 to 1.25 mm/year in the upper part and decrease in winter precipitation from 0 to − 0.25 mm/year in the west part of the region. Annual number of rainy days was also found to decrease in winter up to − 1.33 days/decade where the region receives a major portion of total precipitation. The decrease in winter rainfall and rainy days caused an increase in continuous dry days (around 0.27 days/year) and decrease in continuous wet days (up to − 0.26 days/year). Trend analysis and CDF plot revealed that though the numbers of rainy days are decreasing, the numbers of extreme rainfall days are increasing, which indicates rainfall become more erratic and intense in the region. The increases in both continuous dry days and extreme rainfall days indicate more droughts and floods may have adverse impacts on the hydrology of Pakistan.

This study aimed to investigate the trend of patients with thyroid cancer undergoing thyroidectomy and those undergoing fine needle aspiration (FNA) and its relationship with thyroid cancer, using a large-scale, real-world database established based on the employment-based health insurance claims data in Japan. In this retrospective descriptive study, annual incidence rates of patients with thyroid cancer undergoing thyroidectomy and FNA from 2005 to 2014 were calculated. Among the 3,130,757 enrollees, 926 patients were diagnosed with thyroid cancer and underwent thyroidectomies. The annual incidence of patients with thyroid cancer undergoing thyroidectomy increased from 5.4 (95% confidence interval 95% CI, 3.4–8.5) in 2005 to 11.7 (10.1–13.5) per 100,000 patient-years in 2013, with a gradual increase among patients in their 20s and 30s and with the most notable increase among those in their 40s and 50s. The annual FNA rate also increased during those years, whereas no noticeable change was observed in the thyroid cancer detection rate. The incidence rates of patients with thyroid cancer undergoing thyroidectomy and those undergoing FNA were strongly correlated, with Pearson’s correlation coefficients of 0.935 for men and 0.886 for women. In conclusion, an increasing trend in the incidence of patients with thyroid cancer undergoing thyroidectomy was observed from 2005 to 2013 among a large group of Japanese employees of working age and their dependents. These results provide useful information on the impact of patients with thyroid cancer undergoing thyroidectomy on the working population.

The data from observation of the geomagnetic field variations at the Midlatitude Mikhnevo Geophysical Observatory of Institute of Geosphere Dynamics of the Russian Academy of Sciences, Mikhnevo village, Moscow oblast, Russia (coordinates 54.959° N; 37.766° E) and at the INTERMAGNET international magnetic network station of the Belsk Geophysical Observatory of Geophysical Institute of the Polish Academy of Sciences, Belsk, Poland (coordinates 51.837° N, 20.792° E) in 2008−2016 are analyzed. A long-term trend related to secular variation in the magnetic field of the Earth is studied by the daily-mean values. Annual variation is distinguished in the north horizontal component of the magnetic field. The reliability of the recent version of the International Geomagnetic Reference Field (IGRF-12) model, which was released in December 2014 to describe variations in the main magnetic field at the Mikhnevo and Belsk observatories, is estimated. The 2011 and 2014 jerks are identified.

Background and Purpose: A stroke incidence study in ­Örebro, situated in Southern Sweden, that was carried out in 1999 showed high incidence rates. Since then, in many Western countries, declining incidence rates have been observed. The main purpose of this study is to examine whether there have been any changes in stroke incidence in the city of ­Örebro between 1999 and 2017. Secondary purposes are to show trends in stroke severity, length of stay and case fatality (CF). Methods: The criterion of an “ideal” stroke incidence study was used in both the 1999 and the present investigation. These criteria include uniform diagnostics, case ascertainment including strokes managed outside the hospital, and the use of several overlapping sources, prospective design, well-defined denominator, and a large population. Results: The overall stroke incidence rate of first ever stroke (adjusted to the 2013 European population) dropped from 346/100,000 (95% CI 314–380) to 168/100,000 (95% CI 148–190). Stroke severity declined from a median of 6 to 4 points on the National Institute of Health Stroke scale. CF within 28 days also declined from 19 to 16% (n.s.). Median length-of-stay in hospital was 16 days in 1999, and 10 days in 2017. Twenty-one per cent of all kinds of stroke were recurrent (not included in the above results). Conclusions: During the years between 1999 and 2017, there have been reductions in stroke incidence, severity and mortality. The explanation is most likely to be found in the prevalence of risk factors and how they are treated. The use of antihypertensives and statins has increased, corresponding to lower levels of blood pressure and cholesterol in the population. The use of anticoagulants in patients with atrial fibrillation has increased. Cigarette smoking has decreased. These are encouraging results that show that preventive medication and public health measures work in practice.

Background: The dialysis patient population in the United States continues to grow. Trends in rates of death and hospitalization among dialysis patients have important consequences for outpatient dialysis capacity and Medicare spending. Objectives: To estimate contemporary trends in rates of death and hospitalization among dialysis patients in the United States, overall and within subgroups. Methods: We used Medicare Limited Data Sets (100% sample) in 2014–2017 to estimate trends in rates of death and hospitalization among dialysis patients with Medicare Parts A and B enrollment. We used seasonal autoregressive integrated moving average models to identify secular trends in the incidence of outcomes. Results: There were 631,075 unique patients; 222,924 deaths; and 1,876,779 hospital admissions. Weekly risks of both death and hospitalization exhibited strong seasonality. However, overall weekly risks of death were 34.9, 35.4, 35.2, and 35.7 deaths per 10,000 patients in 2014–2017, respectively (p = 0.47, from a likelihood ratio test of secular trend). The overall weekly risk of hospitalization was 3.08, 3.05, 3.11, and 3.11% in 2014, 2015, 2016, and 2017, respectively (p = 0.30). There were significant secular trends in risk of death in subgroups defined by black race and residency in South Atlantic states (p < 0.05). There were also secular trends in risk of hospitalization in subgroups defined by age 20–44 years, concurrent enrollment in Medicaid, and residency in South Central states. Conclusion: For the first time since the beginning of this century, rates of both death and hospitalization among dialysis patients with Medicare fee-for-service coverage have stagnated. The reasons for this change are unknown and require detailed assessment. Persistent lack of change in clinical outcomes may alter the future expectations about dialysis patient population growth.

Context: A secular trend of progressively earlier attainment of menarche has been described in various populations. The existence of this trend in Ile‑Ife, Nigeria, has not been documented. Aim: To determine the current age of menarche and its trend in comparison with previous studies among secondary school girls in Ile‑Ife, Nigeria. Settings and Design: School‑based cross‑sectional analytical study. Materials and Methods: Three‑hundred secondary school girls in the lower four classes (JSS 1‑‑SSS 1) were studied. Sociodemographic and menstrual data such as cycle length, duration of menstrual flow, and presence of dysmenorrhoea were obtained using a structured self‑administered questionnaire. The mean age at menarche was compared with figures from previous local studies to determine the trend in Ile‑Ife. Menstrual characteristics were also analyzed. Statistical Analysis: Data was analyzed with SPSS version 20. Means and standard deviations were generated for continuous variables, while frequencies and proportions were determined for categorical variables. Results: Out of the 300 subjects studied, a total of 198 (66%) had attained menarche at the time of this study. Their reported ages at menarche ranged from 11 to 17 years with a mean of 13.08 ± 1.61 years. This was lower than the 13.98 ± 1.30 and 13.94 ± 1.31 years reported in Ile‑Ife in 1992 and 1997, respectively. These three figures show a trend of progressive decline in the mean age at menarche. The subjects’ mean duration of menstrual flow was 4.26 ± 0.87 days, with 97.5% of them reporting flow of ≤5 days. Only 22 (11.1%) of the respondents had a cycle length of 28 days. Dysmenorrhoea was reported by 75% of the respondents and 24% reported loss of concentration during periods. Conclusion: Similar to the widely reported secular trend, menarche indeed appears to be occurring progressively earlier in Ile‑Ife, Nigeria.Key words: Adolescence; menarche; menstruation; Nigeria; puberty

In China, as the social transformation and economic development from 1985 to 2015, children's feeding pattern has undergone some changes. So we aimed to analyze the secular trend on feeding patterns of city children in China.All data were from a series of national survey which implemented once every 10 years in China from 1985 to 2015. We use same indexes to evaluate the feeding pattern of children in these four surveys.From 1985 to 2005, the exclusive breastfeeding rates in infants under 6 months of age decreased, especially in suburban areas decreased by 17.7%; the continuous breastfeeding rate of 1-year-old children in suburban area decreased from 60.1 to 27.6%. However, from 2005 to 2015, the exclusive breastfeeding rates under 6 months of age increased by 16.0% in urban areas and 5.9% in suburban areas; the continuous breastfeeding rate of 1-year-old children in urban increased from 17.0 to 36.0%. The overall feeding rate of complementary food in infants under 6 months of age declined from 1985 to 2015; the average age at introduction of all complementary foods was around 6 months of age in 2015.There is an obvious trend on feeding pattern of Chinese children. From 1985 to 2005, the breastfeeding rate decreased, the duration time of breastfeeding was shortened and the age at introduction of complementary food was advanced. From 2005 to 2015, the breastfeeding rate increased, the duration time of breastfeeding was prolonged, and the age at introduction of complementary food was postponed.

Background: Multiple meta-analyses have shown sperm count declines in Western countries spanning eight decades. Secular trends in other parameters remain unclear, as are potential predictors of these trends. Objective: To analyze secular trends in semen quality and to evaluate whether factors previously found to be related to semen quality were responsible for these patterns. Methods: This is a prospective study including 936 men of couples seeking infertility treatment who provided 1618 semen samples at a single center (2000–2017). Self-reported demographic, nutritional and reproductive characteristics were collected using standardized questionnaires. Urinary concentrations of bisphenol A, parabens and phthalates were quantified by isotope-dilution tandem mass spectrometry. Semen samples were analyzed for volume, sperm concentration, count, motility and morphology following WHO guidelines. We estimated the differences in semen parameters over time by fitting generalized linear mixed models with random intercepts to account for repeated samples while adjusting for abstinence time. We also adjusted for demographic, nutritional and environmental factors to investigate these as potential predictors of time trends. Results: Sperm concentration and count declined by 2.62% per year (95% CI −3.84, −1.38) and 3.12% per year (95% CI: −4.42, −1.80), corresponding to an overall decline of 37% and 42%, respectively, between 2000 and 2017. Decreasing trends were also observed for total motility (per year: −0.44 percentage units, 95% CI −0.71, −0.17) and morphologically normal sperm (per year: −0.069 percentage units, 95% CI −0.116, −0.023). These decreases reflected relative percentage declines of 15% and 16% over the 17 year study period, respectively. When reproductive factors were included in the model, the downward trends in sperm concentration and sperm count were attenuated by 29% and 26%, respectively, while the trends in motility and morphology were attenuated by 54% and 53%, respectively. Also, the downward trends in both sperm concentration and sperm morphology over time were attenuated by 19% when including the DEHP and non-DEHP metabolites, respectively. Conclusions: Sperm concentration, total count, motility and morphology significantly declined between 2000 and 2017 among subfertile men. These negative trends were attenuated when considering simultaneous changes in reproductive characteristics and urinary phthalates during the course of the study. Keywords: Semen parameters, Secular trends, Phthalates, Predictors, Male infertility

The first directional archaeomagnetic results from Cyprus are presented, based on the study of seven baked clay structures excavated at the copper smelting site of Agia Varvara-Almyras, situated some 20 km south of Nicosia. This ancient copper working site represents a unique example of complete primary production of the copper metal in Cyprus. In total five furnaces, one ore roasting pit and an oven were sampled in situ for an archaeomagnetic investigation. All the studied structures are well dated, based on pottery finds and radiocarbon dates, with ages ranging from 600 BCE to 50 BCE. Several rock magnetic experiments were performed to determine the main magnetic carrier and to investigate the thermal stability of the studied material. The direction of the Characteristic Remanent Magnetization (ChRM) for each structure has been determined by demagnetization of 7–15 specimens in alternating magnetic fields up to 100–120 mT. Mean directions were calculated assuming a Fisherian distribution and are well defined for five out of the seven structures studied. The new directions are compared with the directional data and the secular variation curves available from the surrounding area, and with the predictions of global geomagnetic field models. They are an important contribution to improving our knowledge of the geomagnetic field variations in the Eastern Mediterranean and offer new insights about fast geomagnetic directional changes during the first millennium BCE that were not previously identified by the available geomagnetic field models’ predictions in this area.

We use numerical dynamo simulations to investigate rapid changes in geomagnetic field intensity. The work is motivated by paleomagnetic observations of ‘geomagnetic spikes’, events where the field intensity rose and then fell by a factor of 2–3 over decadal timescales and a confined spatial region. No comparable events have been found in the historical record and so geomagnetic spikes may contain new and important information regarding the operation of the geodynamo. However, they are also controversial because uncertainties and resolution limitations in the available data hinder efforts to define their spatio-temporal characteristics. This has led to debate over whether such extreme events can originate in Earth's liquid core. Geodynamo simulations produce high spatio-temporal resolution intensity information, but must be interpreted with care since they cannot yet run at the conditions of Earth's liquid core. We employ reversing and non-reversing geodynamo simulations run at different physical conditions and consider various methods of scaling the results to allow comparison with Earth. In each simulation we search for ‘extremal events’, defined as the maximum intensity difference between consecutive time points, at each location on a 2 ∘ latitude–longitude grid at Earth's surface, thereby making no assumptions regarding the spatio-temporal character of the event. Extremal events display spike-shaped time-series in some simulations, though they can often be asymmetric about the peak intensity. Maximum rates of change reach 0.75 μ T yr − 1 in several simulations, the lower end of estimates for spikes, suggesting that such events can originate from the core. The fastest changes generally occur at latitudes > 50 ∘ , which could be used to guide future data acquisitions. Extremal events in the simulations arise from rapid intensification of flux patches as they migrate across the core surface, rather than emergence of flux from within the core. The prospect of observing more spikes in the paleomagnetic record appears contingent on finding samples at the right location and time to sample this particular phase of flux patch evolution.

Los Humeros caldera in eastern Mexico has been formed since about 164 ka, with important effusive activity during the upper Holocene, which covered more than 100 km2 with lava. Two lava flows were 14C dated at 2692-1950 cal BCE and 1117-930 cal BCE, but the detailed succession of eruptions is yet unknown even though the interest for volcanic risk assessment. All Holocene lava flows were studied paleomagnetically in 22 sites to determine which of them have been contemporaneous and to apply the paleomagnetic dating method. For most sites well defined mean directions could be defined, resulting in an overall paleodirection of D = 7.7° E, I = 16.9°, α95 = 6.7°. This direction is discordant compared to the geocentric axial dipole field and indicates that secular variation has not averaged out. Paleointensities were obtained using the Thellier IZZI protocol, with only a small success rate of 27% due to thermally induced alterations, the presence of multidomain magnetic minerals, or unstable paleomagnetic directions as indicated by the checks during the experiments. Accepted paleointensities of 37 samples varied between 21 and 63 μT, with site mean paleointensity of 27–54 μT. The F-test was applied to mean directions of sites potentially belonging to the same lava flow, and if these were indistinguishable they were combined in flow mean paleomagnetic directions. Otherwise, these sites were assumed to represent independent eruptions. This way, thirteen independent flow mean directions were obtained and used for paleomagnetic dating by means of the SHA.DIF.14k reference model and the archaeo_dating software. The dating often provided several possible age ranges, and erosion state, soil cover, lava flow contacts, and the available 14C ages were used all together for selecting the most probable age range. Two well defined eruptive periods bracketed between 2500 and 1900 BCE, and 1300-600 BCE were defined, suggesting that all studied lava flows were emplaced during two main eruptive phases, which may indeed have been much shorter than 600 years. Paleomagnetic data support those eruptive periods and time among the different lava flow units can be inferred from those data. Early settlers occupied this region since about 2000 BCE and thus were certainly affected by these voluminous eruptions. At least another 12 nearby Holocene monogenetic volcanoes are known in the surrounding area, and all together these eruptions indicate that this is a highly active volcanic region, which might be affected by eruptions in the near future.

We estimate the contribution of the systematic component of the Earth’s main magnetic field (MMF), i.e., the main dipole, to the secular variation in the midlatitude polar auroras based on the archived data. It is found that the main features of the variations in the magnetic moment (MM) of the main dipole in 1600–1909 are reflected in variations in the annual number of polar auroras N with the opposite sign (correlation coefficient of 0.6–0.8). A model of the dependence of the number of polar auroras N on the solar activity expressed in the Wolf number W and on the MM value is proposed. Taking into account the effect of the MM noticeably improves the properties of the N versus W dependence. It is found that the disagreement between the 11-year cycles of N and W observed in 1700–1775, as well as the minimum N in ~1760–1767 (Silverman minimum), are conditioned by MM variations in the corresponding periods of time. A rapid increase in the MM near 1800 significantly contributes to the steep decline in N during the Dalton minimum. During those historical periods in which the MM value was 1.5–2 times greater than in the 17th–19th centuries (according to the archeomagnetic data), the number of polar auroras could be conditioned not so much by the solar activity as by the screening effect of the MMF.

Context Astrophysical observations play a critical role in the possibility of variations in fundamental physical constants. One of the ways of probing these variations would be based on the evolution of the white-dwarf stars. Aims We use the spectrum of white-dwarf star G191-B2B to find an upper limit on the possible deviation of the gravitational constant with strong gravitational fields. Methods We analyze archive observation of the Hubble Space Telescope Imaging Spectrograph (HSTIS) to determine the possible cosmological deviation of the gravitational constant from the observed gravitational redshift. Results Our analysis provided a strong estimate on an upper bound on the possible space-time variation of the gravitational constant ̇⁄ = (0.238 ± 2.959) × 10 yr comparing with previous results. Conclusions The obtained result in this study offers the possibility of testing parameters of modern unification theories.

The main purpose of the study was to analyze secular trends of health-related physical fitness in 7–14-year-old Croatian children and adolescents from 1999 and 2014. In this observational cross-sectional study, we recruited 5077 children and adolescents between ages 11 and 14 (50.8% girls) from five primary schools located in the capital city of Zagreb. Physical fitness performance was tested from 1999 until 2014. Physical fitness performance included: (1) body-mass index (measure of body size), (2) standing broad jump (measure of lower-body power), (3) polygon backwards (measure of general coordination and agility), (4) sit-ups in 60 s (measure of upper-body strength), (5) sit-and-reach test (measure of flexibility) and (6) 6-min run test (measure of cardiorespiratory fitness). Boys performed better in all physical fitness tests, except for sit-and-reach test (p

This study analyzes the geophysical signals in J2 time series from 1976 to 2020 by using singular spectrum analysis (SSA) and the Lomb-Scargle (L-S) periodogram for the first time. The results of SSA indicate that the secular trend is characterized by a superposition of the secular linear decrease with a rate of approximately (−5.80 ± 0.08) × 10−11/yr and an obvious quadratic rate of (2.38 ± 0.02) × 10−13/yr2. Besides, the annual, semi-annual, and 10.6-year signals with determining for the first time its amplitude of 5.01 × 10−11, are also detected by SSA, where their stochastic behavior can be maintained to the greatest extent. The 18.6-year signal cannot be detected by SSA even when the window size of 18.6 years was selected, while L-S periodogram can detect the signal of 18.6 years after removing the 18.6-year tidal theoretical value and the linear trend, proving the existence of the tidal variations of 18.6 years in the residual time series. Nevertheless, the 10.6-year signal can be found only after removing the secular trend. This fact suggests that the advantages of different methods used will lead to different sensitivity to the particular signals hard to be detected. Finally, the reconstructed ΔJ2 time series through the sum of the climate-driven contributions from glacial isostatic adjustment (GIA), Antarctic ice sheets (ANT), atmosphere (ATM), continental glaciers (GLA), Greenland ice sheets (GRE), ocean bottom pressure (OBP), and terrestrial water storage (TWS) by using GRACE gravity field solution and geophysical models agrees very well with that of the observed ΔJ2 from SLR in terms of the amplitude and phase. About 81.5% of observed ΔJ2 can be explained by the reconstructed value. ATM, TWS, and OBP are the most significant contributing sources for seasonal signals in ΔJ2 time series, explaining up to 40.1%, 31.9%, and 26.3% of the variances of observed ΔJ2. These three components contribute to the annual and semi-annual variations of the observed ΔJ2 up to 30.1% and 1.6%, 30.8% and 1.0%, as well as 25.4% and 0.7%, respectively. GRE, ANT, and GLA have ~3 to ~7-year periodic fluctuations and a positive linear trend, excluding GIA.

The growth status and weight status of Chinese children have experienced remarkable changes in the past decades. Using China Health and Nutrition Survey (CHNS) data, this paper examines the secular trends and disparity of the growth status and weight status in Chinese children and further investigates the impact of various family environments on children’s growth from 1991 to 2011. We found an increasing trend in standardized growth indicators (height, weight, and BMI), overweight, and obesity from 1991 to 2011. We also observed an increasing disparity in overweight and obesity over time. Family environments had a significant impact on children’s growth status and weight status. In particular, children that live in families with a small size, higher family income, better sanitary conditions, and with well-educated parents or overweight parents tended to be taller and heavier and have a higher BMI, lower risk of being underweight, and higher risk of exhibiting overweight and obesity. Further decomposition analysis showed that more than 70% of the disparity in standardized height, weight, and overweight and around 50% of the disparity in standardized BMI, underweight, and obesity could be attributed to heterogeneity in family environments. Moreover, the disparity associated with family environments tended to increase over time.

This study aimed to consolidate the body height, body weight, BMI, and nutrition status data of the overall young male population from the Municipality of Berane in order to assess the trajectories of those variables from 1979 to 1987. The sample of respondents included 8740 adolescents who were divided into nine groups according to their age. The sample of variables included body height, body weight, body mass index, and nutrition status, which were presented based on a long-established BMI categorization (underweight, normal weight, pre-obese, and obese). The descriptive statistics are expressed as the mean and standard deviation for each variable, the analysis of nutrition status was calculated based on BMI, while LSD post hoc testing with ANOVA was employed to investigate differences between the means. The results indicate that a secular trend is visible regarding body height and body weight, while no trend is visible for the BMI and nutrition status. This study’s contribution is that it provides insight into more recently published data for the studied period and in this municipality, which can significantly aid in following the secular trend throughout Montenegro.

Objective Fractures are a common reason for hospital admissions. However, regional and short-term studies show a varying incidence rate (IR) of fractures, and most of the surveys were conducted from only a few medical centers. Therefore, this study aims to investigate the epidemiological data of fracture hospitalizations of middle-aged and elderly persons in Taiwan between 2000 and 2015. Materials and methods Data from fractures occurring between 2000 and 2015 were obtained from the National Health Insurance Research Database in Taiwan for this study. The IR of fracture admission in patients, aged 40 years or older at the time of admission and first-time diagnosed with a fracture following admission, was calculated. Results We found that the IR of the fracture hospitalizations declined considerably from 95.70 per 10,000 person-years in 2000, to 68.48 per 10,000 person-years in 2015. The three most common fracture hospitalizations accounting for more than 50% of all fractures were fractures of the femur/hip, radius or ulna, and vertebral column. The IR of fracture hospitalization increased with age and was found to be higher in women than in men. The most common cause of fracture hospitalization for men and patients under 65 years of age was traffic accidents. In contrast, falls were the most frequent causes of fracture hospitalization for women and patients over 65 years of age. Conclusion The present study furnishes an updated picture of the incidence of fracture hospitalization over a 16-year period among middle-aged and elderly persons in Taiwan.

Background: Life expectancy has increased markedly in the past decades. Thus, it is of great importance to understand how people are ageing and if the trajectories of health and disability are changing over time. This study aimed to examine trends in functional abilities and health in independent cohorts of people aged 75–95 over three decades. Methods: This Helsinki Ageing Study consists of repeated cross-sectional postal surveys examining independent cohorts of old people (75, 80, 85 and 90+ years old). This study combined data from four waves (1989, 1999, 2009 and 2019). Results: In the most recent wave, there was an increase in the portion of participants who were able to walk outdoors easily (75-year-olds p=0.03, 80-year-olds p=0.002, 85-year-olds p

International audience

International audience; Despite progress in the knowledge of secular variation during the first millennium BCE in Europe, data coverage remains poor at the earliest periods, especially in some regions as in the Central Mediterranean area. This study presents three new directional and six new intensity data between the 13th and the 4th centuries BCE on archaeological kilns, pottery and baked clay fragments from South Italy and France. Archaeodirections were determined after thermal demagnetizations and archaeointensities using the Thellier-Thellier protocol with corrections for the anisotropy and cooling rate effects. The new data confirm the large deviation of the direction from a Geocentric Axial Dipole field, the high geomagnetic field strength and the fast secular variation observed in Europe during the earliest half of the first millennium BCE. Another characteristic of this period is a difference of ~25° between the longitudes of the virtual geomagnetic poles inferred from European and Middle East data. This unusual behaviour can be mainly related to the Levantine Iron Age anomaly (LIAA) and its expansion from the Middle East to Europe. However, the review of the global directional database shows that almost all virtual geomagnetic poles, 96% of them coming from Europe, the Middle East, East Asia, North America and Hawaii, are 10–25° away from the rotation axis towards North Russia between 1000 and 600 BCE. The calculation of a mean global VGP curve suggests that the North geomagnetic pole followed a clockwise motion during this period with a dipole tilt up to around 14°. This study shows that a dipole axis tilt may have played an important role in the rapid secular variation in western Eurasia, although part of this variation may also be related to non-dipole fields associated with the LIAA.

BackgroundInterrupted time series (ITS) are an important tool for determining whether alcohol control policies, as well as other policy interventions, are successful over and above secular trends or chance. Subsequent to estimating whether a policy has had an effect, quantifying the key outcomes, such as the number of prevented deaths, is of primary practical importance. The current paper compares the results of two different methodological approaches to quantify deaths averted using different two standard populations.MethodsTime series methodologies were used to estimate the effect size in deaths averted of a substantial increase in excise taxation in Lithuania in 2017. We compare the impact of a) using ITS methodology vs. fitting the trend before the intervention to predict the following 12 months and comparing the predicted monthly estimates of deaths with the actual numbers; and b) adjusting the time series either using the World Health Organization standard or the age distribution of Lithuania in the month before the intervention. The effect was estimated by sex.ResultsThe increase in excise taxation was associated with a substantial decrease in all-cause mortality in all models considered. ITS methodology and using the age-distribution of Lithuania were consistently associated with higher estimates of deaths averted. Although confidence and prediction intervals were highly overlapping, the point estimates differed substantially. The taxation increase was associated with 1,155 deaths averted in the year following the intervention (95% prediction interval: 729, 1,582), corresponding to 2.80% of all deaths in Lithuania in the respective year, for the model selected as best for planning policy interventions in Lithuania.ConclusionsFitting a time series model for the time until the intervention, and then comparing the predicted time points with the actual mortality, standardizing to country-specific weights, was chosen as the best way to derive practically relevant effect sizes.

Background Gastric cancer remains a leading cause of cancer death worldwide. In Taiwan, gastric cancer is the sixth leading cause of cancer mortality in both males and females. Aim To evaluate secular trends in gastric cancer incidence according to age, sex, and Helicobacter pylori (H. pylori) treatment in Taiwan. Methods In this population-based study, we used the national Taiwan Cancer Registry database. Annual percent changes in incidence rates were used to describe secular trends in incidence rates and sex ratios of gastric cancer in Taiwan. Pearson's product-moment correlation coefficients were used to analyze the correlation between annual age-adjusted incidence rates and the annual number of patients treated with antibiotic therapy for H. pylori infection. Results The annual percent changes showed continuously decreasing rates of gastric cancer among both males and females. However, the decreasing trends differed by sex, with an annual percent change of -2.58% in males and -2.14% in females. The age-specific incidence rates increased with age. Within the same age group, more recent time periods showed lower incidence rates than greater time periods. Similarly, the sex ratio was lower in later birth cohorts than in earlier birth cohorts. Age-adjusted incidence rates substantially decreased with increasing numbers of patients being treated with antibiotic therapy for H. pylori infection during 2005 to 2016 (r = 0.72). Conclusion We observed steadily decreasing trends with differential sex ratios in the incidence of gastric cancer in Taiwan. These results support H. pylori eradication programs in Taiwan.

Background Age at menarche (AAM) has shown different trends in women from different ethnic and economic regions in recent decades. Data on AAM among multiethnic women living in developing areas are scarce. Methods Data on AAM from 1,275,000 women among 26 ethnicities in Yunnan Province, China, who were born from 1965 to 2001 were obtained from the National Free Preconception Health Examination Project from 2010 to 2018. The patterns of AAM trends were analysed according to ethnic group, area of residence, and socioeconomic status. Results The mean AAM was 13.7 ± 1.21 years (95% CI 13.697–13.701), with a decrease from 14.12 (±1.41) among women born before 1970 to 13.3 (±1.04) among those born after 2000. The decline was 0.36 years per 10-year birth cohort, and the plateau has not yet been reached in Yunnan. A secular trend of earlier AAM was observed in all 26 ethnic groups. The fastest rate of decline was observed for the Bai ethnicity (0.36 years per decade). Consistent declining trends in AAM appeared among extreme-, middling-, and nonpoverty economic patterns from 1965 to 2001, with reductions of 1.19, 1.44, and 1.5 years, respectively (P P Conclusion There was a secular trend towards a younger AAM during the twentieth century and early twenty-first century birth cohorts in the Yunnan population. Considering the difference in AAM trends due to ethnic and socioeconomic status in Yunnan, the health authority should utilize flexible adjusted health care strategies in different regions.

ObjectiveRecent changes in birth characteristics in Japan may have a potential influence on children’s developments. Therefore, we investigated secular trends in gross motor milestones.DesignData were collected from an official Japanese nationwide serial cross-sectional survey conducted every 10 years since 1960. 22 320 participants aged 2–18 months were identified from the four surveys from 1980 to 2010.OutcomesWe assessed whether or not a child achieved four gross motor milestones including rolling over (rolling), sitting without support (sitting), standing with support (standing) and walking alone (walking). The target age was defined as the age when the attainment rate ranged from >5% to >95% of the total. Multivariate logistic regression models were fitted.ResultsThe final cohort included 20 570 children. The target ages were determined as follows: 3–6 months for rolling; 5–9 months for sitting; 6–11 months for standing; and 9–15 months for walking. The attainment rates of sitting, standing and walking in 1990 were higher than those in 2010, even after adjusting for child characteristics (sitting: adjusted OR (aOR)=2.07 (95% CI 1.62 to 2.65); standing: aOR=1.63 (95% CI 1.32 to 2.02); and walking: aOR=1.61 (95% CI 1.34 to 1.95)).ConclusionsThe proportion of children who attained three motor milestones (sitting, standing and walking) by set target ages decreased between 1990 and 2010. The contribution of birth characteristics including a decrease in gestational age and fetal growth, as well as changes in other child characteristics, failed to explain why this decrease occurred.

We determined if the increasing trend in hypertension can be partly attributed to increasing prevalence of overweight/obesity in China over the past two decades. Data were collected from 1991 to 2011 and the population attributable risk (PAR), which is used to estimate the intervention effect on hypertension if overweight/obese, were eliminated. Linear regression was used to evaluate the secular trends. The age-standardized prevalence of overweight and obesity increased by 26.32% with an overall slope of 1.27% (95% CI: 1.12–1.43%) per year. Hypertension also increased by 12.37% with an overall slope of 0.65% (95% CI: 0.51–0.79%) per year. The adjusted ORs of overweight/obesity for hypertension across the survey years remained unchanged; however, the trend in PAR increased steadily from 27.1 to 44.6% with an overall slope of 0.81% (95% CI: 0.34–1.28%) per year (P = 0.006). There was no significant gender difference in the slopes of increasing PAR, as measured by regression coefficients (β = 0.95% vs. β = 0.63% per year, P = 0.36). Over the past two decades, the increase in the prevalence of hypertension in China was partly attributed to the overweight/obesity epidemic, which highlights the importance of controlling weight and further reducing the burden of hypertension.

We derive recent surface mass balance (SMB) estimates from airborne radar observations along the iSTAR traverse (2013, 2014) at Pine Island Glacier (PIG), West Antarctica. Ground-based neutron probe measurements provide information of snow and firn density with depth at 22 locations and were used to date internal annual reflection layers. The 2005 layer was traced for a total distance of 2367 km to determine annual mean SMB for the period 2005–2014. Using complementary SMB estimates from two regional climate models, RACMO2.3p2 and MAR, and a geostatistical kriging scheme, we determine a regional-scale SMB distribution with similar main characteristics to that determined for the period 1985–2009 in previous studies. Local departures exist for the northern PIG slopes, where the orographic precipitation shadow effect appears to be more pronounced in our observations, and the southward interior, where the SMB gradient is more pronounced in previous studies. We derive total mass inputs of 79.9±19.2 and 82.1±19.2 Gt yr−1 to the PIG basin based on complementary ASIRAS–RACMO and ASIRAS–MAR SMB estimates, respectively. These are not significantly different to the value of 78.3±6.8 Gt yr−1 for the period 1985–2009. Thus, there is no evidence of a secular trend at decadal scales in total mass input to the PIG basin. We note, however, that our estimated uncertainty is more than twice the uncertainty for the 1985–2009 estimate on total mass input. Our error analysis indicates that uncertainty estimates on total mass input are highly sensitive to the selected krige methodology and assumptions made on the interpolation error, which we identify as the main cause for the increased uncertainty range compared to the 1985–2009 estimates.

Background Falls are one of the major causes of injury globally. However, there is a lack of population-based studies on falls among adolescents, young and middle-aged adults. We therefore aimed to conduct a large-scale population study on the secular trend in incidence of fall-related hospitalization. Methods A population-wide electronic database, Hong Kong's Clinical Data Analysis and Reporting System (CDARS), was used in this retrospective cohort study. Patients aged≥10, hospitalized with diagnosis of accidental falls (ICD-9-CM E880-E888) from 2005-2018, were included. Outcome measures included the number, age- and sex-standardized incidence rate of fall-related hospital admissions, their length of stay (LOS) and 1-year all-cause mortality. Linear regression and average annual percentage change (AAPC) using joinpoint regression were computed for trend analysis. Findings From 2005 to 2018, a total of 336,439 patients aged≥10 were identified with fall-related hospitalization. Among these fall patients, 33.7% occurred at age

Geomagnetic Virtual Observatories (GVOs) are a method for processing magnetic satellite data in order to simulate the observed behaviour of the geomagnetic field at a fixed location. As low-Earth orbit satellites move at around 8 km/s and have an infrequent re-visit time to the same location, a trade-off must be made between spatial and temporal coverage, typically averaging over half the local time orbit precession period, within a radius of influence of 700 km. The annual differences (secular variation, SV) of residuals between GVO time series data and an internal field model at a single GVO location will be strongly correlated with its neighbours due to the influence of large-scale external field sources and the effect of local time precession of the satellite orbit. Using Principal Component Analysis we identify and remove signals related to these noise sources to better resolve internal field variations on sub-annual timescales.We apply our methodology to global grids of monthly GVOs for the Ørsted, CHAMP, CryoSat-2 and Swarm missions, covering the past two decades. We identify common principle components representing orbit precession rate dependent local time biases, and major external field sources, for all satellites. We find that the analysis is enhanced by focussing on regions of geomagnetic latitude where different external field sources dominate, identifying distinct influences in polar, auroral and low-to-mid latitude regions. Annual differences are traditionally used to calculate SV so as to remove annual and semi-annual external field signals, but these signals can be re-introduced if our corrected SV is re-integrated. We find that by representing secular variation with monthly first differences, rather than annual differences, we can identify and remove annual and semi-annual external field variations from the SV, which then improves the use of re-integrated main field GVO time series. By better accounting for contaminating signals from correlated external fields and aliasing, we are able to produce a global grid of GVO time series which better represents internal secular variation at monthly time resolution.

Constraining the secular variations of the Earth’s magnetic field strength in the past is fundamental to understanding short term processes of the geodynamo. Such records constitute a powerful and independent dating tool for archaeological sites and geological formations. In this study, we present 10 new and robust archaeointensity results from Pre-Pottery to Pottery Neolithic and, for one of the first times, flint (burnt chert) from Jordan. Two of these results constitute the oldest archaeointensity data for the entire Levant, ancient Egypt and Mesopotamia extending the archaeomagnetic dating reference for the Holocene. Virtual Axial Dipole Moments (VADM)s show that the Earth’s magnetic field in the Southern Levant was weak (about half the present field) at around 7,600 years BCE, recovering its strength to greater than the present field around 7,100 BCE and gradually weakening again around 5,200 years BCE. In addition, successful results obtained from burnt flint demonstrate the potential of this rarely used material in archaeomagnetic research, in particular for prehistoric periods from the first use of fire to the invention of pottery.

ObjectivesDetermine the temporal trends in cardiorespiratory fitness (CRF) and health risk of Slovenian schoolchildren across a 20-year span, assessed via 20-m shuttle run (20mSRT), including defining centile ranges and possible health risk(s) for each generation.MethodsNationally representative data from 9,426 healthy schoolchildren (6–14 years old) were used to determine changes in CRF across three generations, in 1993 (n = 3,174), 2003 (n = 3,457) and 2013 (n = 2,795) from a multistage, stratified, decennial study.Results20mSRT performance declined ∼2.8% from 1993 to 2003, independent of age or sex of the child. This trend was reversed in 2013, increasing by ∼8.2% across all age groups, for both girls and boys, for a net increase of 5.4%. The magnitude of improvement was similar for both sexes. Moreover, girls in the 2013 generation (for ages 10–13 year) completed more stages than their 2003 male counterparts. Across all generations, children achieved CRF values corresponding to low cardiovascular risk for future health outcomes. Centile values ranged from “low” to “very high” depending on age, sex, and generation of the sample.ConclusionNegative trends in CRF from Slovenian schoolchildren were reversed by 2013, indicating that Slovenia should continue implementing progressive national physical fitness strategies introduced between sampling periods (i.e., 2003–2013). Additionally, due to the universal nature of Slovenian schoolchildren achieving “healthy cut-off values” for 20mSRT (generation-inclusive), it is suggested that more specific cut-off criteria are developed, especially for younger children, and girls, so that future CRF results can be more accurately applied for both clinical and pedagogical users.

OBJECTIVES The aim of the study was to examine a secular trend in age at menarche (AAM) in the former Czechoslovak (and descendant Slovak and Czech) population in relation to its large-scale political and social events taking place after World War II. METHODS The study included 211 women aged 18-30 (born during 1984-1998), and their relatives: mothers, sisters, and grandmothers, yielding a total of 421 women. Changes in retrospectively recalled AAM between the three generations of women (oldest-grandmothers, middle-mothers, and youngest-daughters) were studied in pairwise comparisons. Relationships between AAM and the birth/conception date were analyzed relative to three events in the post-WWII Czechoslovakia (1948, 1968, and 1989). RESULTS AAM was the highest in the oldest generation, slightly lower in the middle generation and the lowest in the youngest generation. Mixed-Effect Model showed statistically significant interaction between the date of conception, historical events, and the period before and after the event. CONCLUSIONS The recorded decline in AAM is congruent with secular trends reported in the literature. However, the decreasing trend was not linear and included an increase in AAM in women conceived within the five-year period after the invasion of Czechoslovakia by communist armies in 1968.

This thesis deals with the application of the Spherical Cap Harmonic Analysis (SCHA) modelling technique to obtain geomagnetic field models for Indonesia, which have better resolution and accuracy than the International Geomagnetic Reference Field (IGRF). B-splines basis function and autoregressive forecasting are applied to improve estimates of secular variation and its forecast over the Indonesian region. The modelling technique is applied to geomagnetic observation data compiled from 68 geomagnetic repeat stations in Indonesia covering the period 1985 - 2015 from BMKG (Badan Meteorologi Klimatologi dan Geofisika / Agency for Meteorology, Climatology, and Geophysics) Indonesia, definitive data from five BMKG geomagnetic observatories and 13 INTERMAGNET (The International Real-Time Magnetic Observatory Network) observatories. Synthetic cartesian X, Y, and Z components at sea level at 17 fixed locations, calculated from IGRF-13, are also used. The area covered by the models in this thesis is the Indonesian region with a spherical cap half-angle of 30° and with the coordinate of the spherical cap pole at 122°E and 3°S. From statistical analysis and comparison with the IGRF, the SCHA model with index k = 7 is considered as the best SCHA model, both in resolution and accuracy. Compared with the root mean square deviation (RMSD) of the IGRF model, the RMSD of the SCHA model with index k = 7 is lower by 28 nT, 11 nT, and 34 nT for X, Y, and Z components, respectively. A model from interpolation of the SCHA with index k = 7 using the B-splines basis function for the year 1985.5 – 2015.5 shows that the SCHA model gives better results than the IGRF. The forecasting calculation for the year 2015.5 – 2020.5 suggests that the autoregressive order 3 of the SCHA with index k = 7 gives better results than the forecasting of the IGRF model, especially in the X, Z, and F components. However, in the Y component, the IGRF is still better than the SCHA model. The RMSD of the forecasted SCHA model is 154.92 nT, 200.87 nT, 104.39 nT, and 135.81 nT for X, Y, Z, and F components, respectively, while the RMSD of the IGRF model is 172.62 nT, 95.52 nT, 117.55 nT, and 162.38 nT for X, Y, Z, and F components. Thus, the forecasted SCHA model is suitable for data reduction of geomagnetic surveys in the Indonesian region but not preferable for navigation.