Influence of temperature on the average velocity of muscle fatigue in Rhinella marina Sartorius

Analizar y comparar el efecto de la temperatura en la velocidad promedio de las etapas de la fase lineal y de la fase exponencial de la fatiga producida por estimulación periódica con sacudida simple o con tétanos en el sartorio de sapo. Métodos: Estudio experimental, in vitro; muestra: 46 músculos de sartorio de sapo seleccionados aleatoriamente. A las temperaturas estudiadas, se midió la tensión pico producida con dos patrones de estímulo (sacudida simple o tétanos) hasta llegar en cada caso a un tipo de fatiga muscular, se calculó la velocidad de caída de la tensión en las etapas de la fase lineal y en la fase exponencial de cada tipo de fatiga y se compararon las pendientes de las regresiones obtenidas con la ecuación de Arrhenius. Resultados: Las temperaturas utilizadas (1 a 12°C) afectaron significativamente (p0,05). Conclusiones: La temperatura afectó significativamente la velocidad promedio de desarrollo de la fatiga en las diferentes fases de los dos tipos de fatiga, pero al comparar las pendientes de la mayoría de las regresiones correspondientes de Arrhenius, no se encontraron diferencias significativas, lo cual sugiere que, los mecanismos que subyacen a las diferentes etapas de la fatiga tienen igual sensibilidad a la temperatura.To analyze and compare the effect of temperature on the average velocity of the linear phase and the exponential phase stages produced by periodic stimulation with simple twitching or with tetanus in the toad sartorius. Methods: an in vitro experimental study with a sample of 46 toad sartorius muscles randomly selected. At the temperatures studied, peak tension produced with two stimulus patterns (twitching and tetanus) were measured until reaching the corresponding muscle fatigue in each case. The tension velocity drop in the linear phase and the exponential phase for each type of fatigue were calculated, and the regression slopes obtained with the Arrhenius equation were compared. Results: The temperatures used (1 to 12°C) significantly affected the velocity of fatigue in the stages of linear and exponential phases of both types of fatigue (p 0.05). Conclusions: The temperature significantly affected average development velocity of fatigue in the different phases of the two types of fatigue, but when comparing slopes of most regressions corresponding to Arrhenius there were no significant differences, suggesting that the mechanisms underlying the different stages of fatigue have equal sensitivity to temperature

Rediscovering Cova de la Sarsa (València, Spain): a Multidisciplinary Approach to One of the Key Early Neolithic Sites in the Western Mediterranean

Cova de la Sarsa (València, Spain) is one of the most important Neolithic impressed ware culture archaeological sites in the Western Mediterranean. It has been widely referenced since it was excavated in the 1920s, due partly to the relatively early excavation and publication of the site, and partly to the qualitative and quantitative importance of its archaeological remains. Unfortunately, as it was an older excavation and lacked present-day rigorous methodological approaches, this important site has been somewhat relegated to the background in the reviews about the Neolithic at the end of the 20th century. However, during the last few years, both the site itself and its archaeological remains have been the object of new studies that hopefully will return the site to the forefront of discussions about the Mediterranean Neolithic. We here present the most relevant results of the research carried out by our group (i.e., pottery study, radiocarbon dating, and isotope analysis), and contextualize them within the dense research history of the cave and the studies carried out by other colleagues with the purpose of revisiting its materials and increasing the knowledge available from the site. Radiocarbon dates on human remains show that the cave was used during prehistoric times as a funerary space longer than expected, and also sporadically afterwards. The characterization of the pottery assemblage concludes that most materials belong to the Early Neolithic. Isotopic analysis portrays an overall similar diet based on terrestrial C3 resources throughout prehistoric times, with a possible varied dietary protein input between individuals during the Early Neolithic

Diet at the onset of the Neolithic in northeastern Iberia : an isotope-plant microremain combined study from Cova Bonica (Vallirana, Catalonia)

The emergence of Neolithic societies was transformative, impacting many aspects of life, particularly diet. The process of Neolithization in Iberia is increasingly understood as the arrival of new people from the Central Mediterranean, who dispersed along the Iberian coasts introducing cereal production, herding, and Cardial pottery and associated material culture. Although research has clarified aspects of the cultigen-dominated economy of these new people, questions remain due to the limitations of conventional archaeobotanical and archaeozoological methods that tend to produce indirect evidence. The extent to which these early farmers adopted Mesolithic staples, which are often difficult to detect with other methods, remains unclear. Furthermore, questions surround the nature of methods of food preparation Cardial Neolithic people used when incorporating grains into their diet. In this study, we examined direct evidence of the diet from the Iberian Cardial Neolithic site of Cova Bonica (Vallirana, Baix Llobregat, Catalonia) using CN stable isotopes on bone and plant microremains trapped in dental calculus from six human individuals and associated fauna. Isotopes show a diet based on terrestrial C3 resources, with no isotopic evidence of aquatic or C4 resource consumption. Plant microremains (starches and phytoliths) provide evidence of cereal use, as well as of other plant foods. However, perhaps due to Bonica's early farmers' choice of grain variety, their grain processing methods, or due to specific dental calculus formation factors, the grain assemblages are rather limited and provide scarce information on food preparation

Dataciones radiocarbónicas de la Cova de la Sarsa (Bocairent, València)

La revisión de los materiales arqueológicos recuperados en la Cova de la Sarsa nos ha llevado a establecer una serie de propuestas sobre sus diferente

The influence of religious identity and socio-economic status on diet over time, an example from medieval France

In Southern France as in other parts of Europe, significant changes occurred in settlement patterns between the end of Antiquity and the beginning of the Middle Ages. Small communities gathered to form, by the tenth century, villages organized around a church. This development was the result of a new social and agrarian organization. Its impact on lifestyles and, more precisely, on diet is still poorly understood. The analysis of carbon and nitrogen isotopes in bone collagen from the inhabitants of the well-preserved medieval rural site Missignac-Saint Gilles le Vieux (fifth to thirteenth centuries, Gard, France) provides insight into their dietary practices and enables a discussion about its transformation over time. A sample of 152 adult individuals dated from 675 to 1175 AD (75 females, 77 males) and 75 specimens from 16 non-human species were analyzed. Results show the exploitation of freshwater, marine, and terrestrial ecosystems as well as various breeding practices specific to each species. The use of both C4 and halophyte plants for feeding domestic animals was also observed. Concerning human dietary practices, a change seemed to occur at the beginning of the tenth century with an increase of δ15N values and a decrease of δ13C values. This corresponds to the introduction of a significant amount of freshwater resources into the diet and could be related to the evolution of the Catholic doctrine. A concomitant diversification of access to individual food resources was also observed, probably linked to the increased diversity of practice inside a population otherwise perceived as one community

Effect Of Nb And Cu On The Crystallization Behavior Of Understoichiometric Nd–Fe–B Alloys

In this work, we present a complete study of the influence of Nb and Cu addition on the crystallization behavior of Nd-lean Nd-Fe-B melt-spun alloys. Alloys with compositions Nd10-x-yFe84B6NbxCuy (x = 1, y = 0 and x = 0.5, y = 0.5) were melt-spun at different wheel speeds (15-40 m s(-1)) to obtain samples in amorphous, highly disordered and nanocrystalline structures. The crystallization process, induced by different heat treatments, was studied by means of differential thermal analysis and x-ray powder thermodiffraction. Magnetic properties of as-made and heat-treated ribbons were measured by magnetometry. The as-made amorphous samples showed a crystallization to the 2: 14: 1 hard magnetic phase at T-1 similar to 350 degrees C. Doping with Nb results in an increase of T1, and addition of Cu lowers T1. This behavior is explained in terms of an inhibition of grain growth by Nb and a nucleation enhancement by Cu additions. During the crystallization process, a secondary phase (identified as a bcc-Fe-rich phase) is formed. The amount of such a phase increases with the annealing temperature. Coercivity increases upon annealing reaching maxima at 700-750 degrees C. This can be explained in terms of competition between the two phases formed: the 2: 14: 1 hard phase and the soft bcc-Fe-rich phase. The highest coercivity of the Nd-lean samples is observed when the microstructure is appropriate and both phases are exchange-coupled.This work has received funding from the DOE BES-DE-FG02-90ER45413 and the European Union MSCA grant agreement No 691235 (INAPEM). Technical and human support provided by SGIker (UPV/EHU, GV/EJ and ESF) is gratefully acknowledged

Microremains from El Mirón Cave human dental calculus suggest a mixed plant/animal subsistence economy during the Magdalenian in Northern Iberia

Despite more than a century of detailed investigation of the Magdalenian period in Northern Iberia, our understanding of the diets during this period is limited. Methodologies for the reconstruction of Late Glacial subsistence strategies have overwhelmingly targeted animal exploitation, thus revealing only a portion of the dietary spectrum. Retrieving food debris from calculus offers a means to provide missing information on other components of diet.We undertook analysis of human dental calculus samples from Magdalenian individuals (including the ¿Red Lady¿) at El Mir on Cave (Cantabria, Spain), as well as several control samples, to better understand the less visible dietary components. Dental calculus yielded a diverse assemblage of microremains from plant, fungal, animal and mineral sources that may provide data on diet and environment. The types of microremains show that the individuals at El Mir on consumed a variety of plants, including seeds and underground storage organs, as well as other foods, including possibly bolete mushrooms. These findings suggest that plant and plant-like foods were parts of her diet, supplementing staples derived from animal foods. As faunal evidence suggests that the Magdalenian Cantabrian diet included a large proportion of animal foods, we argue here for a mixed subsistence pattern

Physical activity quantification in elder women

Cuantificación de la actividad física en mujeres mayores

Neanderthal diets in central and southeastern Mediterranean Iberia

During recent decades, Neanderthal diet has been a major research topic in palaeoanthropology. This has been accelerated by the maturation of different techniques, which have produced a plethora of new information. However, this proliferation of data has led to confusing and contradictory results. Furthermore, most of the ecological dietary studies have been carried out on specimens drawn from different time periods and regions, almost exclusively those characterized by cold, open environmental conditions. Subsistence models based on these fragmentary data have been applied to Neanderthals living in a variety of different regions and environments, even though their dietary strategies may have been as variable as regions they inhabited. In this paper we integrate different dietary approaches (studies of the zooarchaeology, stable isotopes and plant remains) from the central and southeastern Mediterranean coast of Iberia in order to develop a broader and more complex picture of Neanderthal diet in different Mediterranean environmental conditions. Our results suggest that there may have been some minor dietary variation due to climatic or environmental differences, but that Neanderthal diet focussed on large terrestrial game, supplemented by plant foods when these were available