Reflexiones sobre etnoarqueología contemporánea

This article discusses some of the central topics in ethnoarchaeology and approaches them from a Latin American perspective. The development of the subdiscipline is summarized and analyzed, and case studies in the region are provided. Moreover, since ethnoarchaeology in Latin America cannot be detached from the state of the discipline in the rest of the world, there are references to global developments that aim to contextualize these case studies. Some of the criticisms made against the subdiscipline are included as well, and they are discussed in the light of the current situation. Ethnoarchaeology’s contributions to the interpretation of the archaeological record and to theory building in archaeology are examined. It is concluded that one of the main contributions of ethnoarchaeology is the mitigation of the ethnocentrism that permeates the archaeological view of the people in the past and the interpretation of long-term human processes. With its particular purview on contemporary societies, ethnoarchaeology is providing substantial input, not only to the understanding of human behavior, but also to archaeological theory.Este artículo analiza algunos de los temas centrales de la etnoarqueología y se acerca a ellos desde una perspectiva latinoamericana. Resume y discute el desarrollo de la subdisciplina y proporciona ejemplos de esta región. Además, dado que la etnoarqueología en América Latina no puede entenderse desligada de los avances de la disciplina en el resto del mundo, se incluyen referencias a otros ámbitos geográficos a escala mundial para contextualizar estos ejemplos. También se incluyen algunas de las críticas formuladas contra la subdisciplina y se discuten teniendo en cuenta las tendencias actuales. Se examinan las contribuciones de la etnoarqueología a la interpretación del registro arqueológico y a la construcción de la teoría arqueológica. El artículo concluye que una de las principales aportaciones de la etnoarqueología es que ayuda a mitigar el etnocentrismo que impregna la interpretación arqueológica de las poblaciones pasadas y la interpretación de los procesos humanos a largo plazo. Con su enfoque particular en las sociedades contemporáneas, la etnoarqueología está proporcionando una aportación sustancial, no sólo para la comprensión de la conducta humana, sino también para la construcción de la teoría arqueológica

Cholinergic imaging in dementia spectrum disorders

The multifaceted nature of the pathology of dementia spectrum disorders has complicated their management and the development of effective treatments. This is despite the fact that they are far from uncommon, with Alzheimer’s disease (AD) alone affecting 35 million people worldwide. The cholinergic system has been found to be crucially involved in cognitive function, with cholinergic dysfunction playing a pivotal role in the pathophysiology of dementia. The use of molecular imaging such as SPECT and PET for tagging targets within the cholinergic system has shown promise for elucidating key aspects of underlying pathology in dementia spectrum disorders, including AD or parkinsonian dementias. SPECT and PET studies using selective radioligands for cholinergic markers, such as [(11)C]MP4A and [(11)C]PMP PET for acetylcholinesterase (AChE), [(123)I]5IA SPECT for the α(4)β(2) nicotinic acetylcholine receptor and [(123)I]IBVM SPECT for the vesicular acetylcholine transporter, have been developed in an attempt to clarify those aspects of the diseases that remain unclear. This has led to a variety of findings, such as cortical AChE being significantly reduced in Parkinson’s disease (PD), PD with dementia (PDD) and AD, as well as correlating with certain aspects of cognitive function such as attention and working memory. Thalamic AChE is significantly reduced in progressive supranuclear palsy (PSP) and multiple system atrophy, whilst it is not affected in PD. Some of these findings have brought about suggestions for the improvement of clinical practice, such as the use of a thalamic/cortical AChE ratio to differentiate between PD and PSP, two diseases that could overlap in terms of initial clinical presentation. Here, we review the findings from molecular imaging studies that have investigated the role of the cholinergic system in dementia spectrum disorders

Caza, recolección y pesca como estrategia de explotación de recursos en forestas tropicales lluviosas: los nukak de la Amazonía colombiana.

Sin resume

Ship-hull shape optimization with a T-spline based BEM-isogeometric solver

In this work, we present a ship-hull optimization process combining a T-spline based parametric ship-hull model and an Isogeometric Analysis (IGA) hydrodynamic solver for the calculation of ship wave resistance. The surface representation of the ship-hull instances comprise one cubic T-spline with extraordinary points, ensuring C2 continuity everywhere except for the vicinity of extraordinary points where G1 continuity is achieved. The employed solver for ship wave resistance is based on the Neumann-Kelvin formulation of the problem, where the resulting Boundary Integral Equation is numerically solved using a higher order collocated Boundary Element Method which adopts the IGA concept and the T-spline representation for the ship-hull surface. The hydrodynamic solver along with the ship parametric model are subsequently integrated within an appropriate optimization environment for local and global ship-hull optimizations against the criterion of minimum resistance

High-efficiency forming processes for complex thin-walled titanium alloys components: State-of-the-art and Perspectives

Complex thin-walled titanium alloy components play a key role in the aircraft, aerospace and marine industries, offering the advantages of reduced weight and increased thermal resistance. The geometrical complexity, dimensional accuracy and in-service properties are essential to fulfill the high-performance standards required in new transportation systems, which brings new challenges to titanium alloy forming technologies. Traditional forming processes, such as superplastic forming or hot pressing, cannot meet all demands of modern applications due to their limited properties, low productivity and high cost. This has encouraged industry and research groups to develop novel high-efficiency forming processes. Hot Gas Pressure Forming (HGPF) and hot stamping-quenching technologies have been developed for the manufacture of tubular and panel components, and are believed to be the cut-edge processes guaranteeing dimensional accuracy, microstructure and mechanical properties. This article intends to provide a critical review of high-efficiency titanium alloy forming processes, concentrating on latest investigations of controlling dimensional accuracy, microstructure and properties. The advantages and limitations of individual forming process are comprehensively analyzed, through which, future research trends of high-efficiency forming are identified including trends in process integration, processing window design, full cycle and multi-objective optimization. This review aims to provide a guide for researchers and process designers on the manufacture of thin-walled titanium alloy components whilst achieving high dimensional accuracy and satisfying performance properties with high efficiency and low cost