6,979 research outputs found

    First GIS analysis of modern stone tools used by wild chimpanzees (Pan troglodytes verus) in Bossou, Guinea, West Africa

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    Stone tool use by wild chimpanzees of West Africa offers a unique opportunity to explore the evolutionary roots of technology during human evolution. However, detailed analyses of chimpanzee stone artifacts are still lacking, thus precluding a comparison with the earliest archaeological record. This paper presents the first systematic study of stone tools used by wild chimpanzees to crack open nuts in Bossou (Guinea-Conakry), and applies pioneering analytical techniques to such artifacts. Automatic morphometric GIS classification enabled to create maps of use wear over the stone tools (anvils, hammers, and hammers/anvils), which were blind tested with GIS spatial analysis of damage patterns identified visually. Our analysis shows that chimpanzee stone tool use wear can be systematized and specific damage patterns discerned, allowing to discriminate between active and passive pounders in lithic assemblages. In summary, our results demonstrate the heuristic potential of combined suites of GIS techniques for the analysis of battered artifacts, and have enabled creating a referential framework of analysis in which wild chimpanzee battered tools can for the first time be directly compared to the early archaeological record.Leverhulme Trust [IN-052]; MEXT [20002001, 24000001]; JSPS-U04-PWS; FCT-Portugal [SFRH/BD/36169/2007]; Wenner-Gren Foundation for Anthropological Researc

    The Power of Non-Determinism in Higher-Order Implicit Complexity

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    We investigate the power of non-determinism in purely functional programming languages with higher-order types. Specifically, we consider cons-free programs of varying data orders, equipped with explicit non-deterministic choice. Cons-freeness roughly means that data constructors cannot occur in function bodies and all manipulation of storage space thus has to happen indirectly using the call stack. While cons-free programs have previously been used by several authors to characterise complexity classes, the work on non-deterministic programs has almost exclusively considered programs of data order 0. Previous work has shown that adding explicit non-determinism to cons-free programs taking data of order 0 does not increase expressivity; we prove that this - dramatically - is not the case for higher data orders: adding non-determinism to programs with data order at least 1 allows for a characterisation of the entire class of elementary-time decidable sets. Finally we show how, even with non-deterministic choice, the original hierarchy of characterisations is restored by imposing different restrictions.Comment: pre-edition version of a paper accepted for publication at ESOP'1

    Estimativa de sequestro de carbono numa população espontânea de palmeiras macaúba.

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    Este trabalho teve por objetivo estimar o estoque de carbono e a concentração de nutrientes da biomassa de uma população espontânea de palmeiras macaúba (Acrocomia aculeata (Jacq.) Lodd. ex Mart.) em associação com pastagem de Brachiaria ruziziensis. A área foi desmatada há cerca de 25 anos e situa-se em Planaltina, DF. Após realização de inventário da densidade populacional e medições de altura e diâmetro, foram abatidos cinco exemplares representativos que foram divididos nos compartimentos: estipe, raízes, folhas. Amostras representativas passaram por secagem, pesagem e moagem, determinação dos teores de carbono, celulose, lignina e nutrientes e estoques de carbono. A média dos teores de carbono por unidade de biomassa de raízes e folhas foi de 45,3% e 41,0%, respectivamente. No estipe, a concentração de C e lignina variaram em função da altura e representaram em média 43,7% e 15% de C e lignina, respectivamente. Considerando a ponderação da concentração de C por seção e compartimento da planta, o estoque de carbono estimado para biomassa de 89 plantas ha-1 foi de 19,51 Mg C ha-1. Além do sequestro de C, esse sistema florestal sinalizou ser relevante na contribuição para o armazenamento e ciclagem de nutrientes

    Changes in attitudes to awareness of hypoglycaemia during a hypoglycaemia awareness restoration programme are associated with avoidance of further severe hypoglycaemia episodes within 24 months: the A2A in HypoCOMPaSS study

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    Aims/hypothesis: The aims of this study were to assess cognitions relating to hypoglycaemia in adults with type 1 diabetes and impaired awareness of hypoglycaemia before and after the multimodal HypoCOMPaSS intervention, and to determine cognitive predictors of incomplete response (one or more severe hypoglycaemic episodes over 24 months). Methods: This analysis included 91 adults with type 1 diabetes and impaired awareness of hypoglycaemia who completed the Attitudes to Awareness of Hypoglycaemia (A2A) questionnaire before, 24 weeks and 24 months after the intervention, which comprised a short psycho-educational programme with optimisation of insulin therapy and glucose monitoring. Results: The age and diabetes duration of the participants were 48±12 and 29±12 years, respectively (mean±SD). At baseline, 91% reported one or more severe hypoglycaemic episodes over the preceding 12 months; this decreased to <20% at 24 weeks and after 24 months (p=0.001). The attitudinal barrier hyperglycaemia avoidance prioritised (2p=0.250, p=0.001) decreased from baseline to 24 weeks, and this decrease was maintained at 24 months (mean±SD=5.3±0.3 vs 4.3±0.3 vs 4.0±0.3). The decrease in asymptomatic hypoglycaemia normalised from baseline (2p=0.113, p=0.045) was significant at 24 weeks (1.5±0.3 vs 0.8±0.2). Predictors of incomplete hypoglycaemia response (one or more further episodes of severe hypoglycaemia) were higher baseline rates of severe hypoglycaemia, higher baseline scores for asymptomatic hypoglycaemia normalised, reduced change in asymptomatic hypoglycaemia normalised scores at 24 weeks, and lower baseline hypoglycaemia concern minimised scores (all p<0.05). Conclusions/interpretation: Participation in the HypoCOMPaSS RCT was associated with improvements in hypoglycaemia-associated cognitions, with hyperglycaemia avoidance prioritised most prevalent. Incomplete prevention of subsequent severe hypoglycaemia episodes was associated with persistence of the cognition asymptomatic hypoglycaemia normalised. Understanding and addressing cognitive barriers to hypoglycaemia avoidance is important in individuals prone to severe hypoglycaemia episodes. Clinical trials registration: www.isrctn.org: ISRCTN52164803 and https://eudract.ema.europa.eu: EudraCT2009-015396-27. Graphical abstract: [Figure not available: see fulltext.]. (c) 2022, The Author(s)

    Acute Effects of Low-and High-Speed Resistance Exercise on Cognitive Function in Frail Older Nursing-Home Residents: A Randomized Crossover Study

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    Aim. The present study investigated the acute effects of low-and high-speed resistance exercise on the cognitive function of frail older women living in nursing home. Materials and Methods. Ten institutionalized frail older women were recruited. Rey Auditory Verbal Learning Test and Stroop test were performed before, immediately after, 1 h after, and 24 h after the end of the experimental session. Participants randomly performed low-and high-speed resistance exercise and a control session. Exercise sessions were composed of 4 resistance exercises with 4-8 sets of 4-10 repetitions at moderate intensity. Results. Results indicated that the performance of Rey Auditory Verbal Learning Test was similarly increased immediately after both low-and high-speed resistance exercises. However, only improvements elicited by low-speed resistance exercise remained significant 1 h after the end of the exercise session. No acute effects of resistance exercise were observed on Stroop performance. Conclusion. Our findings indicated that both low-and high-speed resistance exercises acutely increased episodic memory in frail older women, whereas no changes on Stroop were observed
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