2,051 research outputs found

    Discriminación experimental de los rasgos técnicos en la talla bipolar y a mano alzada en lascas a través los cuarzos de Naibor Soit (Garganta de Olduvai, Tanzania)

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    La identificación de la talla bipolar puede ser controvertida debido fundamentalmente a la naturaleza petrográfica del cuarzo y a su fracturación heterogénea. Este trabajo pretende superar este problema mediante el desarrollo de un marco explicativo experimental destinado al reconocimiento de los rasgos diagnósticos en las lascas producidas por ambos métodos de talla en la reducción del cuarzo de Naibor Soit (Garganta de Olduvai, Tanzania). El objetivo final de este trabajo es el de utilizar un conjunto de variables relacionadas con la respuesta de esta materia prima a la fractura a mano alzada y bipolar en dos experimentos destinados a individualizar estadísticamente los rasgos técnicos diagnósticos que mejor identifican a la talla bipolar en este tipo de materia prima

    Back from the dead: Another response to the contextual bases of the Rising Star ‘deliberate body disposal’ hypothesis

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    Significance: The hypothesis that >1500 Middle Pleistocene hominin bones represent the remains of complete corpses deposited deliberately in Rising Star Cave by conspecifics is provocative. This is because intentional handling of dead bodies might imply these hominins had developed a uniquely human sense of mortality salience >235 000 years ago. We assess the contextual bases of this hypothesis and find they do not, in fact, provide its unequivocal support. In sum, critical assessment of relevant geological and taphonomic data disallows falsification of the null hypothesis that the assemblage formed as the result of a non-anthropogenic process(es). Because so, the ‘deliberate body disposal’ hypothesis remains unsupported

    Site index estimation using airborne laser scanner data in Eucalyptus dunnii maide stands in Uruguay

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    Intensive silviculture demands new inventory tools for better forest management and planning. Airborne laser scanning (ALS) was shown to be one of the best alternatives for high-precision inventories applied to productive plantations. The aim of this study was to generate multiple stand-scale maps of the site index (SI) using ALS data in the intensive silviculture of Eucalyptus dunnii Maide plantations in Uruguay. Forty-three plots (314.16 m3) were established in intensive E. dunnii plantations in the departments of Río Negro and Paysandú (Uruguay). ALS data were obtained for an area of 1995 ha. Linear and Random Forest models were fitted to estimate the height and site index, and OrpheoToolBox (OTB) software was used for stand segmentation. Linear models for dominant height (DH) estimation had a better fit (R2 = 0.84, RMSE = 0.94 m, MAPE = 0.04, Bias = 0.002) than the Random Forest (R2 = 0.85, RMSE = 1.27 m, MAPE = 7.20, Bias=−0.173) model when including only the 99th percentile metric. The coefficient between RMSE values of the cross-validation and RMSE of the model had a higher value for the linear model (0.93) than the Random Forest (0.75). The SI was estimated by applying the RF model, which included the ALS metrics corresponding to the 99th height percentile and the 80th height bicentile (R2 = 0.65; RMSE = 1.62 m). OTB segmentation made it possible to define a minimum segment size of 2.03 ha (spatial radius = 30, range radius = 1 and minimum region size = 64). This study provides a new tool for better forest management and promotes the need for further progress in the application of ALS data in the intensive silviculture of Eucalyptus spp. plantations in Uruguay

    Los micromamíferos (Lagomorpha, Eulipotyphla y Rodentia) del yacimiento del Pleistoceno Medio de Cuesta de la Bajada (Teruel, España): Estudio sistemático y consideraciones paleoambientales

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    The micromammal association established in this work is the following: Lagomorpha: Oryctolagus cuniculus; Eulipotyphla: Crocidura cf. russula, cf. Sorex sp., Neomys sp., Soricidae indet. and Talpa sp.; and Rodentia: Eliomys quercinus, Apodemus cf. sylvaticus, Cricetulus (Allocricetus) bursae, Arvicola aff. sapidus, Microtus (Iberomys) brecciensis and Microtus (Terricola) duodecimcostatus. This association is characteristic of the Middle Pleistocene. The morphological state of Cricetulus (A.) bursae, Arvicola aff. sapidus and Microtus (I.) brecciensis allows to place it in the advanced, but not final, Middle Pleistocene, which agrees with the numerical data of the site (243–337 ka) that places it in the MIS 8 or 9. The micromammals indicate the predominance of the open spaces with abundant vegetation mainly of herbaceous and bushes but also with some areas with trees. The climate would be of Mediterranean type, similar to the actual or perhaps a little milder and more humid.La asociación de micromamíferos determinada en este trabajo es la siguiente: Lagomorpha: Oryctolagus cuniculus; Eulipotyphla: Crocidura cf. russula, cf. Sorex sp., Neomys sp., Soricidae indet. y Talpa sp.; y Rodentia: Eliomys quercinus, Apodemus cf. sylvaticus, Cricetulus (Allocricetus) bursae, Arvicola aff. sapidus, Microtus (Iberomys) brecciensis y Microtus (Terricola) duodecimcostatus. Es una asociación característica del Pleistoceno Medio. El estadio evolutivo de Cricetulus (A.) bursae, Arvicola aff. sapidus y Microtus (I.) brecciensis le aproximan a las poblaciones de dichas especies de algunos yacimientos de la Península Ibérica del Pleistoceno Medio avanzado, pero no final, lo que es acorde con las dataciones numéricas obtenidas en el yacimiento (243-337 ka) que le sitúan en el MIS 8 o 9. Los micromamíferos indican la predominancia de los espacios abiertos con abundante vegetación herbácea y arbustiva, en los que podría haber también alguna zona arbolada. El clima que indican es de tipo mediterráneo, similar al actual en la zona o quizás algo más benigno y más húmedo

    Ovulatory Response of Weaned Sows to an Altered Ratio of Exogenous Gonadotrophins

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    [EN] At weaning, 33 mixed parity Hypor sows received either an injection of 400 IU equine chorionic gonadotrophin and 200 IU human chorionic gonadotrophin (hCG) (PG600; n = 13), PG600 with an additional 200 IU hCG 24 h later (Gn800; n = 11), or served as non-injected controls (n = 9). All gonadotrophin treated sows received an injection of 750 IU hCG at 80 h after weaning to induce ovulation (designated as time 0 h). At 0, 24, 36, 40, 44, 48, and 60 h, all sows were subject to transrectal ultrasonography to determine numbers and sizes of large (>6 mm) follicles and time of ovulation. The interval from injection of 750 IU hCG to ovulation was shorter in Gn800 compared to PG600 sows (p = 0.02), and more Gn800 sows had ≥9 preovulatory follicles compared to PG600 and controls (p = 0.02 and 0.003, respectively). Follicular cysts were evident in both PG600 and Gn800 sows.SIThis work was supported by California State University Agriculture Research Institute (Grants 58982 and 58909), and CalPoly internal funding programs Baker/Koob and RSCA.We gratefully acknowledge Merck Animal Health, for financial support and the provision of PG600 and Chorulon

    Earliest Porotic Hyperostosis on a 1.5-Million-year-old Hominin, olduvai gorge, Tanzania.

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    Meat-eating was an important factor affecting early hominin brain expansion, social organization and geographic movement. Stone tool butchery marks on ungulate fossils in several African archaeological assemblages demonstrate a significant level of carnivory by Pleistocene hominins, but the discovery at Olduvai Gorge of a child's pathological cranial fragments indicates that some hominins probably experienced scarcity of animal foods during various stages of their life histories. The child's parietal fragments, excavated from 1.5-million-year-old sediments, show porotic hyperostosis, a pathology associated with anemia. Nutritional deficiencies, including anemia, are most common at weaning, when children lose passive immunity received through their mothers' milk. Our results suggest, alternatively, that (1) the developmentally disruptive potential of weaning reached far beyond sedentary Holocene food-producing societies and into the early Pleistocene, or that (2) a hominin mother's meat-deficient diet negatively altered the nutritional content of her breast milk to the extent that her nursing child ultimately died from malnourishment. Either way, this discovery highlights that by at least 1.5 million years ago early human physiology was already adapted to a diet that included the regular consumption of meat

    Chicken litter: A waste or a source of chemicals? Fast pyrolysis and hydrothermal conversion as alternatives in the valorisation of poultry waste

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    Poultry production is one of the main and fastest developing branches of the agri-food industry in the world. Chicken litter (ChL) is the most abundant waste from this industry and requires alternative treatments to help mitigate the environmental impacts of improper disposal. Fast pyrolysis and hydrothermal conversion are two recognized thermochemical approaches for the transformation of different types of biomasses, including agro-industrial waste. Fast pyrolysis takes place at atmospheric pressure or under vacuum at moderate to high temperatures (400–800 °C) in the absence of oxygen and requires drying of the feedstock, whereas hydrothermal conversion is a low temperature (180–300 °C) and high pressure (up to 30 MPa) process that takes place in liquid water and particularly suited for moist materials. In this work, we present experimental results that provide a comparison of bio-oils produced by fast pyrolysis and hydrothermal conversion of ChL. In addition, the composition of the pyrolytic oils from ChL is compared with the data obtained from rice husk (the main component of ChL), studied previously. Fast pyrolysis experiments were carried out in a bed reactor at temperatures ranging from 400° to 700°C and at two reaction times of 20- and 40-min. Phenols and other oxygenated compounds were the main families of chemicals present in the bio-oils. Among oxygenated derivatives, fatty acids were predominant. Hydrothermal conversion experiments were performed between 220 and 240 °C for 20- and 40- min and the oil fraction was obtained by evaporation of water from the reaction mixture followed by freeze-drying. These bioliquids were found to be concentrated in fatty acids, especially palmitic acid.EEA Concepción del UruguayFil: Pachón Gómez, Erica M. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Química Orgánica. Instituto de Investigaciones en Fisicoquímica de Córdoba; ArgentinaFil: Pachón Gómez, Erica M. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Fisicoquímica de Córdoba; ArgentinaFil: Domínguez, Rodrigo E. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Química Orgánica. Instituto de Investigaciones en Fisicoquímica de Córdoba; ArgentinaFil: Domínguez, Rodrigo E. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Fisicoquímica de Córdoba; ArgentinaFil: López, Débora A. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Química Orgánica. Instituto de Investigaciones en Fisicoquímica de Córdoba; ArgentinaFil: López, Débora A. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Fisicoquímica de Córdoba; ArgentinaFil: Téllez, Jhoan F. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Química Orgánica. Instituto de Investigaciones en Fisicoquímica de Córdoba; ArgentinaFil: Téllez, Jhoan F. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Fisicoquímica. Instituto de Investigaciones en Fisicoquímica de Córdoba; ArgentinaFil: Téllez, Jhoan F. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Fisicoquímica de Córdoba; ArgentinaFil: Marino, Marcos D. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Química Orgánica. Instituto de Investigaciones en Fisicoquímica de Córdoba; ArgentinaFil: Marino, Marcos D. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Fisicoquímica de Córdoba; ArgentinaFil: Almada, Natalia Soledad. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Concepción del Uruguay; Argentina.Fil: Gange, Juan Martí­n. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Concepción del Uruguay; ArgentinaFil: Moyano, E. Laura. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Química Orgánica. Instituto de Investigaciones en Fisicoquímica de Córdoba; ArgentinaFil: Moyano, E. Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Fisicoquímica de Córdoba; Argentin

    A Wear Analysis Carried On Connecting Rod Bearings From Internal Combustion Engines

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    In the present work, an analysis was carried out to know the wear modes present in connecting rod bearings from internal combustion engines. These mechanical elements were selected since they are exposed to different engineering failures such as incorrect assembly, severe loads, extreme temperatures, inadequate conditions, and loss of lubricity. In this particular case, the bearings that were selected had a service life of approximately 8 years. Different techniques such as SEM and optical microscopy, EDS analysis, hardness testing, and surface profilometry were used to characterize the unworn and worn bearings. Wear mechanisms such as sliding wear (scoring), fatigue wear with cracks where torn out material was clearly observed, discoloration areas, and two- and three-body abrasion wear (rubbing marks) were identified on the bearing surfaces

    Radioactive Iodine Administration Is Associated with Persistent Related Symptoms in Patients with Differentiated Thyroid Cancer

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    Context. Radioiodine (RAI) administration has adverse effects in patients treated for thyroid cancer (DTC), but there is scarce information regarding their intensity and duration. Objective. To evaluate frequency and intensity of early and late RAI-related symptoms in patients with DTC. Design. Observational prospective study. Patients. DTC patients who underwent thyroidectomy, with or without RAI. Measurements. Patients answered 2 surveys: (1) from 0 to 6 months and (2) between 6 and 18 months after initial treatment. Results. 110 patients answered the first survey and 61 both. Nearly 80 percent received RAI. Among early symptoms, periorbital edema, excessive tearing, salivary gland disturbances, dry mouth, taste disorders, and nausea were more frequent and intense among RAI patients. Regarding late symptoms, periorbital edema, salivary gland pain and swelling, and dry mouth were more frequent and intense in RAI patients. Frequency and intensity of adverse effects were not different between low and high RAI doses (50 versus ≥100 mCi). Conclusion. RAI-related symptoms are frequent and usually persist after 6 months of administration, even when low doses are given. This finding must be considered when deciding RAI administration, especially in low risk patients, among whom RAI benefit is controversial
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