Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 10 de 10
Filtrar
Mais filtros










Intervalo de ano de publicação
1.
Sci Rep ; 12(1): 705, 2022 01 13.
Artigo em Inglês | MEDLINE | ID: mdl-35027636

RESUMO

Venta Micena, an Early Pleistocene site of the Baza Basin (SE Spain), preserves a rich and diverse assemblage of large mammals. VM3, the main excavation quarry of the site, has been interpreted as a den of the giant hyaena Pachycrocuta brevirostris in the plain that surrounded the Baza palaeolake. Taphonomic analysis of VM3 has shown that the hyaenas scavenged the prey previously hunted by the hypercarnivores, transported their remains to the communal den, and consumed the skeletal parts according to their marrow contents and mineral density. In a recent paper (Luzón et al. in Sci Rep 11:13977, https://doi.org/10.1038/s41598-021-93261-1 , 2021), a small sample of remains unearthed from VM4, an excavation quarry ~ 350 m distant from VM3, is analysed. The authors indicate several differences in the taphonomic features of this assemblage with VM3, and even suggest that a different carnivore could have been the agent involved in the bone accumulation process. Here, we make a comparative analysis of both quarries and analyse more skeletal remains from VM4. Our results indicate that the assemblages are broadly similar in composition, except for slight differences in the frequency of megaherbivores, carnivores and equids according to NISP values (but not to MNI counts), the degree of bone weathering, and the intensity of bone processing by the hyaenas. Given that VM4 and VM3 were not coeval denning areas of P. brevirostris, these differences suggest that during the years when the skeletal remains were accumulated by the hyaenas at VM3, the rise of the water table of the Baza palaeolake that capped with limestone the bones was delayed compared to VM4, which resulted in their more in-depth consumption by the hyaenas.

2.
Sci Rep ; 9(1): 15408, 2019 10 28.
Artigo em Inglês | MEDLINE | ID: mdl-31659231

RESUMO

Ancient evidence of human presence in Europe is recorded in several Early Pleistocene archaeopalaeontological sites from Spain, France and Italy. This is the case of Barranco León (BL) and Fuente Nueva-3 (FN-3), two localities placed near the town of Orce (depression of Baza and Guadix, SE Spain) and dated to ~1.4 Ma. At these sites, huge assemblages of Oldowan tools and evidence of defleshing, butchering and marrow processing of large mammal bones have been recovered together with a deciduous tooth of Homo sp. in the case of level BL-D. In this study, we: (i) describe in detail the anthropic marks found in the bone assemblages from these sites; (ii) analyse patterns of defleshment, butchery and marrow processing, based on the modifications identified in the cortical surface of the fossils; and (iii) discuss on the subsistence strategies of the first hominins that inhabited the European subcontinent during Early Pleistocene times.


Assuntos
Arqueologia , Fósseis , Hominidae/fisiologia , Comportamento de Utilização de Ferramentas , Animais , Hominidae/anatomia & histologia , Espanha
3.
J Hum Evol ; 77: 167-78, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25439708

RESUMO

Energetic approaches have been increasingly used to address key issues in Neandertal palaeoecology and palaeobiology. Previous research has focused exclusively on the energy requirements of adults and highlights the high energy demands of these individuals compared with modern humans. Less attention has been paid to the energy requirements of sub-adult Neandertals, even though this age group could provide clues for a better understanding of Neandertal life history. Accordingly, herein, we estimate the energy costs of maintenance and growth in Neandertal infants and children from one to six years of age and compare these costs with values for modern humans. Statural growth models for two modern human populations (Beasain and Evenki) and an average Neandertal model population are used to establish weight growth models. In turn, these models of body weight growth are used to estimate key components of energetic variables (basal metabolic rate, total energy expenditure, energy of growth and daily energy requirements). Between three and six years of age, Neandertal children have slightly lower basal and growth energy costs than do modern humans of the same age, due primarily to their smaller body mass and slower growth rates. The reduction in energy allocated to growth is likely the result of metabolic adaptations to other somatic factors and thermal stress. Data from contemporary human infants and children suggest that even mild cold stress increases non-shivering thermogenesis, thus elevating metabolic needs by 50% or more. These results suggest that thermal stress likely played a strong role in shaping the delayed developmental patterns and lower energy allocated to growth during early life in Neandertals relative to Homo sapiens.


Assuntos
Metabolismo Basal/fisiologia , Homem de Neandertal/crescimento & desenvolvimento , Animais , Estatura/fisiologia , Regulação da Temperatura Corporal/fisiologia , Peso Corporal/fisiologia , Criança , Pré-Escolar , Metabolismo Energético , Feminino , Humanos , Lactente , Masculino
4.
PLoS One ; 9(7): e101938, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25054305

RESUMO

Increasing evidence suggests that the European human settlement is older than 1.2 Ma. However, there is a fierce debate about the continuity or discontinuity of the early human settlement of Europe. In particular, evidence of human presence in the interval 0.7-0.5 Ma is scarce in comparison with evidence for the previous and later periods. Here, we present a case study in which the environmental conditions at Sierra de Atapuerca in the early Middle Pleistocene, a period without evidence of human presence, are compared with the conditions in the previous period, for which a relatively intense human occupation is documented. With this objective in mind, the available resources for a human population and the intensity of competition between secondary consumers during the two periods are compared using a mathematical model. The Gran Dolina site TD8 level, dated to 0.7-0.6 Ma, is taken as representative of the period during which Atapuerca was apparently not occupied by humans. Conditions at TD8 are compared with those of the previous period, represented by the TD6-2 level, which has yielded abundant evidence of intense human occupation. The results show that survival opportunities for a hypothetical human population were lower at TD8 than they were at TD6-2. Increased resource competition between secondary consumers arises as a possible explanation for the absence of human occupation at Atapuerca in the early Middle Pleistocene.


Assuntos
Comportamento Competitivo/fisiologia , Fenômenos Ecológicos e Ambientais , Ecossistema , Modelos Teóricos , Algoritmos , Animais , Biomassa , Europa (Continente) , Alimentos , Fósseis , Hominidae , Humanos , Dinâmica Populacional , Fatores de Tempo
5.
J Hum Evol ; 64(6): 645-57, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23541385

RESUMO

Food resource availability strongly influences the survival opportunities of all organisms. The effect of animal food resource availability on the survival and dispersal of hominin populations is hotly debated. In this article, we present a mathematical model that provides estimations of the maximum and minimum available resources for secondary consumers in a palaeocommunity. This model provides insights into the intensity of competition and the available niche space for hominins in Europe during the early Galerian (1.2-0.8 Ma). Published data from the Atapuerca TD6 assemblage were used in combination with the model to investigate trophic dynamics and resource availability for a Homo antecessor population 800,000 years ago. The effect on our results of the possible presence at Atapuerca of some large carnivores not recorded in the fossil assemblage is also evaluated. Results indicate the existence of a rich ecosystem at Atapuerca at the end of the Early Pleistocene. Secondary production was abundant enough to maintain a hunter-gatherer population and a rich carnivore guild more diverse than that recorded in the TD6 assemblage. Based on these results, the practice of cannibalism by H. antecessor cannot be explained by a long-term scarcity of resources. High food availability at TD6 implies a low to moderate level of competition for resources between carnivores and humans. According to this interpretation, an empty niche for a highly carnivorous omnivore existed in Europe during the early Galerian, and it was successfully exploited by Homo.


Assuntos
Carnívoros , Ecossistema , Hominidae , Modelos Teóricos , Animais , Comportamento Competitivo , Europa (Continente) , Dinâmica Populacional
6.
Rev Neurol ; 52(1): 20-6, 2011 Jan 01.
Artigo em Espanhol | MEDLINE | ID: mdl-21246490

RESUMO

INTRODUCTION: Diverse evidences have shown that the process of natural aging causes a decline in different cognitive functions, including among them the attentional process. AIM: To determine how the healthy aging affects to the different attentional networks. SUBJECTS AND METHODS: Two groups: young subjects (32.5 ± 9.7 years) and an elderly group (62.7 ± 4.7 years). As instrument to evaluate the attention process the ANT (Attention Network Test) was used. RESULTS: Highly significant differences were observed for all conditions involved in the ANT (no cue, center cue, spatial cue, congruent and incongruent) between both groups (p < 0.001). As for the analysis of network effects, no one showed differences between the two groups. Considering the block variable, the post hoc analysis showed that the orienting network for the young subjects exhibited a normal benefit in the first block while the elderly group don't show that benefit caused by the deficiency using spatial cues. Moreover, the alerting network showed a bigger effect in the first block regarding the second one in the older adults and the opposed effect for the executive and orienting network was observed. CONCLUSIONS: The obtained data show that a decrease exists in the speed processing in the elderly group. In the orienting network seems that the older adults require a bigger training period to use the spatial cues, although later on, they can benefit from the same cues almost at the same level that the young subjects.


Assuntos
Envelhecimento/fisiologia , Atenção/fisiologia , Cognição/fisiologia , Rede Nervosa/fisiopatologia , Adulto , Idoso , Transtornos Cognitivos/etiologia , Transtornos Cognitivos/fisiopatologia , Sinais (Psicologia) , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Tempo de Reação , Adulto Jovem
7.
Rev. neurol. (Ed. impr.) ; 52(1): 20-26, 1 ene., 2011. tab, ilus
Artigo em Espanhol | IBECS | ID: ibc-86954

RESUMO

Introducción. Existen diversas evidencias de que el proceso de envejecimiento natural ocasiona un declive en las diferentes funciones cognitivas, incluyendo la atención. Sujetos y métodos. Dos grupos de estudio: jóvenes (32,5 ± 9,7 años) y adultos mayores saludables (62,7 ± 4,7 años). Como instrumento para evaluar la atención utilizamos el test de redes atencionales –Attention Network Test (ANT)–. Resultados. En el ANT, en lo que respecta al tiempo de reacción ante las diferentes condiciones que se dan (sin clave, clave central, clave espacial, congruencia e incongruencia), encontramos diferencias significativas en todas ellas entre ambos grupos (p < 0,001). En cuanto al análisis de redes, éstas no mostraron diferencias entre ambas muestras. Si comparamos el efecto por bloques del ANT, el análisis post hoc mostró que la red de orientación para los sujetos jóvenes presenta un beneficio por el uso de las claves espaciales en el primer bloque, mientras que para los sexagenarios no. Además, la red de alerta mostró un mayor efecto en el primer bloque respecto del segundo en los adultos mayores y el efecto opuesto para la red ejecutiva y de orientación. Conclusiones. Los datos obtenidos muestran que existe una disminución en la velocidad de procesamiento en las personas mayores. En el caso particular de la red de orientación parece que los mayores requieren un intervalo temporal mayor para emplear las claves espaciales, aunque posteriormente tras cierto entrenamiento pueden beneficiarse de éstas casi al mismo nivel que los sujetos jóvenes (AU)


Introduction. Diverse evidences have shown that the process of natural aging causes a decline in different cognitive functions, including among them the attentional process. Aim. To determine how the healthy aging affects to the different attentional networks. Subjects and methods. Two groups: young subjects (32.5 ± 9.7 years) and an elderly group (62.7 ± 4.7 years). As instrument to evaluate the attention process the ANT (Attention Network Test) was used. Results. Highly significant differences were observed for all conditions involved in the ANT (no cue, center cue, spatial cue, congruent and incongruent) between both groups (p < 0.001). As for the analysis of network effects, no one showed differences between the two groups. Considering the block variable, the post hoc analysis showed that the orienting network for the young subjects exhibited a normal benefit in the first block while the elderly group don’t show that benefit caused by the deficiency using spatial cues. Moreover, the alerting network showed a bigger effect in the first block regarding the second one in the older adults and the opposed effect for the executive and orienting network was observed. Conclusions. The obtained data show that a decrease exists in the speed processing in the elderly group. In the orienting network seems that the older adults require a bigger training period to use the spatial cues, although later on, they can benefit from the same cues almost at the same level that the young subjects (AU)


Assuntos
Humanos , Atenção/fisiologia , Envelhecimento/fisiologia , Processos Mentais/fisiologia , Nível de Alerta/fisiologia , Estilo de Vida Saudável , Transmissão Sináptica/fisiologia , Rede Nervosa/fisiologia , Condução Nervosa/fisiologia , Orientação/fisiologia
8.
Am J Ther ; 3(3): 212-218, 1996 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-11862252

RESUMO

BACKGROUND: Skin and skin structure infections are among the most common infectious diagnoses in both the hospital and community settings. If untreated, these infections can produce serious complications. Successful antimicrobial therapy for these infections requires coverage against the causative pathogens, particularly Staphylococcus aureus. OBJECTIVE: This randomized, single-blind, multicenter study was designed to compare the efficacy and safety of intravenous ceftazidime 2 g given two times daily (BID) with that of intravenous ceftazidime 1 g given three times daily (TID) for the treatment of skin and skin structure infections caused by ceftazidime-sensitive pathogens. METHODS: Adults (greater-than-or-equal18 years) were eligible for enrollment if they were hospitalized or in home health care settings and they had a skin or skin structure infection caused by a ceftazidime-sensitive pathogen. Patients were randomly assigned to receive ceftazidime 2 g every 12 h or ceftazidime 1 g every 8 h as an intermittent infusion over 15--30 min. Treatment was continued for 2--3 days beyond the time the patient became asymptomatic or evidence of bacterial eradication was obtained; however, total treatment duration had to be at least 5 days. Patients were assessed for their clinical and bacteriological response at the end of treatment and for their clinical response at follow-up. RESULTS: A total of 806 patients were enrolled in the study, 406 of whom received ceftazidime 2 g BID and 400 of whom received ceftazidime 1 g TID. Both treatments were administered for a mean duration of 9 days. At the end of therapy, 248 of 264 (94%) clinically evaluable patients receiving ceftazidime BID and 258 of 275% (94%) clinically evaluable patients receiving ceftazidime TID achieved clinical cure or improvement (p = 0.953). Pathogens were eradicated or presumed to be eradicated from 217 of 256 (85%) bacteriologically evaluable patients receiving ceftazidime BID and from 228 of 266 (86%) bacteriologically evaluable patients receiving ceftazidime TID (p = 0.760). Of 1131 isolates, the most common pathogens were S. aureus (30%) and Pseudomonas aeruginosa (10%). Both regimens were well tolerated with only 13 patients (3%) in the BID group and 16 patients (4%) in the TID group withdrawing because of an adverse event. CONCLUSIONS: These data indicate that ceftazidime 2 g given twice daily is as effective as ceftazidime 1 g given three times daily for the treatment of skin and skin structure infections. In addition, the twice-daily regimen has the advantage of convenience.

10.
Rev. costarric. cienc. méd ; 10(4): 61-69, dic. 1989. ilus
Artigo em Espanhol | LILACS | ID: lil-107635

RESUMO

En ocho pacientes con candidiasis sistémica y dos con meningitis por Cryptococcus neoformans se administró fluconazol inicialmente por vía intravenosa y luego por vía oral. Fueron evaluados solo 9 pacientes al final del tratamiento, ya que un paciente con SIDA y candidiasis sistémica falleció por una severa infección pulmonar causada por Pneumocystis carinii durante la segunda semana de tratamiento. La duración jdel tratamiento fue de 6 semanas para los procesos candidiásicos y de 12 semanas para las meningitis por Cryptococcus neoformans. La mejoría clínica se alcanzó como promedio en 13 días y la negativización de los estudios micológicos en menos de tres semanas. En los pacientes evaluados, el 100 por ciento alcanzó la curación clínica y micológica. Los efectos adversos e indeseables fueron mínimos y se presentaron en solo 3 pacientes: flebitis, naúseas, vómito y dolor abdominal. La efectividad, tolerancia, penetración al líquido cefalorraquídeo y la posibilidad de administración oral, hacen del fluconazol una droga antimicótica potente, segura, efectiva y fácil de administrar en el tratamiento de los procesos fúngicos severos.


Assuntos
Candidíase/tratamento farmacológico , Criptococose/tratamento farmacológico , Fluconazol/uso terapêutico , Meningite/tratamento farmacológico , Preparações Farmacêuticas
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...