306 research outputs found

    An Acheulean handaxe from Gladysvale Cave site, Gauteng, South Africa.

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    WE DESCRIBE A SINGLE HANDAXE FROM fossiliferous breccias at Gladysvale Cave, South Africa. The artefact is the only known tool so far discovered during the controlled excavations conducted at this site over the last decade, and was recovered from decalcified sediments near the stratigraphic interface of two breccia units, making it difficult to assign it with confidence to either. The morphology of the handaxe indicates a middle-late Acheulean industry, and preliminary electron spin resonance and palaeomagnetic dating suggest an age of greater than 780 000 years.NCS2016http://hdl.handle.net/10520/EJC9652

    Self-rated health in Europe and its determinants: Does generation matter?

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    Objectives: To analyse the influence of micro- and macro-factors on self-rated health, and the role of generation on this relationship. Methods: Cross-sectional study using data from European Health Interview Surveys from 14 European countries. Individuals were divided into four generations (“silent generation”, “baby boomers”, and “generation X” and “Y”). We conducted multilevel analyses for each generation to study the influence of individual and national explanatory variables on self-rated health. Results: Age showed an exponential effect in older generations. Education and employment presented the strongest association with low self-rated health, especially in “baby boomers” and women (low education: OR 3.5; 95% CI 3.2–3.9). Tobacco showed a negative effect in younger generations. Overweight and low physical activity were negatively associated with self-rated health regardless of generation. Countries from the Eastern welfare system showed the highest risk of low self-rated health and this association was higher in men for “silent generation” (OR 4.7; 95% CI 3.0–7.6). Conclusions: The influence of individual and national factors on self-rated health varies regarding generation. The target generation and the demographic structure of a country should be taken into account to develop more accurate health policies

    Distribution, characteristics and potential of biomass-dense thinning forests in Sweden

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    Understanding the characteristics of unutilized biomass resources, such as small-diameter trees from biomass-dense thinning forests (BDTF) (non-commercially-thinned forests), can provide important information for developing a bio-based economy. The aim of this study was to describe the areal distribution, characteristics (biomass of growing stock, tree height, etc.) and harvesting potential of BDTF in Sweden. A national forest inventory plot dataset was imported into a geographical information system and plots containing BDTF were selected by applying increasingly stringent constraints. Results show that, depending on the constraints applied, BDTF covers 9-44% (2.1-9.8 M ha) of the productive forest land area, and contains 7-34% of the total growing stock (119-564 M OD t), with an average biomass density of 57 OD t ha^-1. Of the total BDTF area, 65% is located in northern Sweden and 2% corresponds to set-aside farmlands. Comparisons with a study from 2008 indicate that BDTF area has increased by at least 4% (about 102 000 ha), in line with general trends for Sweden and Europe. Analyses revealed that the technical harvesting potential of delimbed stemwood (over bark, including tops) from BDTF ranges from 3.0 to 6.1 M OD t yr^-1 (7.5 to 15.1 M m^3 yr^-1), while the potential of whole-tree harvesting ranges from 4.3 to 8.7 M OD t yr^-1 (10.2 to 20.6 M m3 yr^-1) depending on the scenario considered. However, further technological developments of the harvest and supply systems are needed to utilize the full potential of BDTF

    Palaeontology and geological context of a Middle Pleistocene faunal assemblage from the Gladysvale Cave, South Africa

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    Palaeontological and geological research at the Gladysvale Cave during the last decade has concentrated on de-roofed deposits located outside the Main Chamber. This area has been termed the Gladysvale External Deposit (GVED) and consists of fossil-rich calcified and decalcified sediments. Here we report on the recent analysis of both the faunal material and the geological context of this deposit. The faunal assemblage, excavated from the decalcified sediments contains 29 mammal species including taxa rare or absent in the Witwatersrand Plio-Pleistocene fossil record (e.g. Pelorovis and Kobus leche). Carnivores and porcupines are identified as accumulating agents of the bones. No new hominin findings can be reported from this deposit, and no cultural remains have been recovered. Geologically the calcified and decalcified breccias represent part of a large talus cone that is relatively unexposed. Uniquely for a cave fill in the Witwatersrand hominin-bearing sites, the sediments are horizontally stratified and form a number of flowstone bound sequences. The dating of the in situ cemented sediments is based on electron spin resonance (ESR) and palaeomagnetism. Recent results indicate that the deposits are of Middle-Pleistocene age.Palaeo-Anthropology Scientific Trust; French Embassy in South Africa; Co-operation and Cultural Service; National Geographic Society; John Nash and family; DACEL; University of the Witwatersrand Research Office and School of Geosciences; World Heritage Site Committee; SAHRA; Swiss National Science Foundation; NSF Grants ILl 9151111 and SBR 989628

    Fundamental, Quantitative Traits of the “Sociotype”

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    In whatever domain of life, from cells to organisms to societies, communicative exchanges underlie the formation and maintenance, and decay, of the emerging collective structures. It can be clearly seen in the human social world. The different classes of social bonds in a complex society revolve around, and are intimately related with, the communicative relationships that every individual entertains—essentially via face-to-face conversation. In the present work we have investigated the fundamental metrics of both social bonds and communicative exchanges along the development of the “sociotype” construct. It is a new approach developed by the authors within the genotype-phenotype-sociotype conceptual triad. The sociotype means the relative constancy, or better the similar fabric, of the social world in which each individual life is developed. In order to ascertain the metrics of the fundamental quantitative traits inherent in the sociotype, a fieldwork involving a total of 1475 individuals (68.59% female, and 49.79 mean age, SD = 21.47) was carried out. The four relational realms of family, friends, work/study, and acquaintances were investigated. The overall results about conversation time (an average of 220 min/day), and about the number of social bonds (an average of 98), differ from previous assumptions, such as Dunbar's number or Killworth's number. Other results about gender, age, and use of social media and Internet contribute to highlight significant differences among the different social segments, and particularly the diminished “sociotype” of the elderly. Finally, it is curious that a non-Gaussian distribution has been obtained for the specific population allotment of these metrics, and intriguingly the Planckian distribution equation (PDE) appears to be a most cogent fit

    Control of the rotary inverted pendulum through threshold-based communication

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    [EN] This paper deals with the real implementation of an event-based control structure for the classical rotary inverted pendulum. The communication between controller and plant is performed through Ethernet (TCP/IP) which leads to a Networked Control System. The bandwidth used by the control loop is reduced, compared with the one that needs a conventional control, by using a threshold-based communication. The values of the thresholds have been determined by means of simulation techniques. The results over the real plant show how this technique can reach a significant reduction of the bandwidth consumed with a negligible worsening of the performance.This work was supported by the Spanish Ministerio de Economía y Competitividad under Grant referenced TEC2012-31506.Casanova Calvo, V.; Alcaina-Acosta, JJ.; Salt Llobregat, JJ.; Pizå, R.; Cuenca Lacruz, ÁM. (2016). Control of the rotary inverted pendulum through threshold-based communication. ISA Transactions. 62:357-366. https://doi.org/10.1016/j.isatra.2016.01.0093573666

    Response of vegetation to drought time-scales across global land biomes

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    We evaluated the response of the Earth land biomes to drought by correlating a drought indexwith three global indicators of vegetation activity and growth: vegetation indices from satellite imagery, tree-ring growth series, and Aboveground Net Primary Production (ANPP) records. Arid and humid biomes are both affected by drought, and we suggest that the persistence of thewater deficit (i.e., the drought time-scale) could be playing a key role in determining the sensitivity of land biomes to drought. We found that arid biomes respond to drought at short time-scales; that is, there is a rapid vegetation reaction as soon as water deficits below normal conditions occur. This may be due to the fact that plant species of arid regions havemechanisms allowing them to rapidly adapt to changing water availability. Humid biomes also respond to drought at short time-scales, but in this case the physiological mechanisms likely differ fromthose operating in arid biomes, as plants usually have a poor adaptability to water shortage. On the contrary, semiarid and subhumid biomes respond to drought at long time-scales, probably because plants are able to withstand water deficits, but they lack the rapid response of arid biomes to drought. These results are consistent among three vegetation parameters analyzed and across different land biomes, showing that the response of vegetation to drought depends on characteristic drought time-scales for each biome. Understanding the dominant time-scales at which drought most influences vegetation might help assessing the resistance and resilience of vegetation and improving our knowledge of vegetation vulnerability to climate change

    Linking Psychosocial Stress Events, Psychological Disorders and Childhood Obesity

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    There is scientific evidence that supports a strong association between early exposure to stressful life events and the presence of health complications throughout adulthood and, to a lesser extent, in adolescence and childhood. The aim of this study was to examine the accumulation of Psychosocial Stress Events (PSE) and the prevalence of mental disorders in children from 8 to 12 years. The association between these factors and child weight measurements was analysed. A cross-sectional study was conducted among 200 children classified by weight status (obesity, overweight and normal-weight). The assessment was carried out in primary care centres and primary schools. An experienced team carried out a structured medical-psychosocial history and a semi-structured interview aimed at identifying an early diagnosis of psychological disorders. Children filled out a questionnaire to evaluate PSE. The obesity group presented the greatest accumulation of PSE and highest prevalence of psychiatric diagnosis, compared to overweight and normal-weight children. To exceed four or more stressful events was positively associated with psychological problems and child body mass index (BMI z-score). A predictive model confirmed the interaction between a larger number of PSE and the occurrence of a psychiatric diagnosis as variables that predispose children by 26.2 times more to increased weight status. In conclusion, the accumulation of PSE in the family, school and social environments of the children was related to greater psychological distress. If not managed, the likelihood of suffering from other health complications, such as excess weight2020-2

    Evidence of increasing drought severity caused by temperature rise in southern Europe

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    We use high quality climate data from ground meteorological stations in the Iberian Peninsula (IP) and robust drought indices to confirm that drought severity has increased in the past five decades, as a consequence of greater atmospheric evaporative demand resulting from temperature rise. Increased drought severity is independent of the model used to quantify the reference evapotranspiration. We have also focused on drought impacts to droughtsensitive systems, such as river discharge, by analyzing streamflow data for 287 rivers in the IP, and found that hydrological drought frequency and severity have also increased in the past five decades in natural, regulated and highly regulated basins. Recent positive trend in the atmospheric water demand has had a direct influence on the temporal evolution of streamflows, clearly identified during the warm season, in which higher evapotranspiration rates are recorded. This pattern of increase in evaporative demand and greater drought severity is probably applicable to other semiarid regions of the world, including other Mediterranean areas, the Sahel, southern Australia and South Africa, and can be expected to increasingly compromise water supplies and cause political, social and economic tensions among regions in the near future.This work has been supported by research projects CGL201127574CO202, CGL201127536 and CGL2011–24185 financed by the Spanish Commission of Science and Technology and FEDER, ‘Demonstration and validation of innovative methodology for regional climate change adaptation in the Mediterranean area (LIFE MEDACC)’ financed by the LIFE programme of the European Commission, CTTP1/12, financed by the Comunidad de Trabajo de los Pirineos, and QSECA (PTDC/AAGGLO/ 4155/2012) funded by the Portuguese Foundation for Science and Technology (FCT). ASL was supported by a postdoctoral fellowship from the Catalan Government (2011 BPB 00078) and CAM was supported by a Juan de la Cierva fellowship by the Spanish Government
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