50 research outputs found

    Lithic raw materials availability in the northeastern coast of magellan strait (chile): An exploratory approach

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    Se caracteriza la disponibilidad de materias primas líticas en la costa nororiental del estrecho de Magallanes (Magallanes, Chile) a partir de la información obtenida en nueve muestreos de roca realizados entre bahía Posesión y bahía Laredo siguiendo la metodología propuesta por Franco y Borrero (1999) para el muestreo de fuentes secundarias de aprovisionamiento lítico. Se describe la abundancia, riqueza, calidad para la talla y tamaño de las rocas disponibles en los depósitos costeros. La determinación microscópica de cortes delgados de roca permitió la identificación petrográfica de distintos tipos, especialmente entre las rocas de grano fino oscuras, los cuales corresponden a variedades diferentes a aquellas más frecuentes en el campo volcánico Pali Aike. Los nuevos datos se discuten en el marco de la información glaciológica y arqueológica disponible para el área y en una escala mayor, en comparación con los resultados previos obtenidos en el campo volcánico Pali Aike.Lithic raw materials availability in the northeastern coast of the strait of Magellan (Magellan, Chile) is characterized by means of nine rock samples collected between Posesión and Laredo bays following Franco and Borrero’s (1999) sampling methodology. Abundance, richness, flintknapping quality and size of rocks in coastal deposits are described. Thin section microscopic determinations allowed us to identify several types of lithic raw materials, especially of fine-grained dark rocks, which are different to those usually present in the Pali Aike volcanic field. These new data are discussed in relationship with the glaciological and archaeological information available for the area, and in a greater scale in comparison to previous results obtained from the Pali Aike volcanic field.Fil: Charlin, Judith Emilce. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Multidisciplinario de Historia y Ciencias Humanas; ArgentinaFil: D’Orazio, Massimo. Università degli Studi di Pisa; Itali

    A trial acoustic improvement in a lecture hall with MPP sound absorbers and FDTD acoustic simulations

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    Sound absorbing micro-perforated panels (MPPs) are being increasingly used because of their high quality in terms of hygiene, sustainability and durability. The present work investigates the feasibility and the performance of MPPs when used as an acoustic treatment in lecture rooms. With this purpose, three different micro-perforated steel specimens were first designed following existing predictive models and then physically manufactured through 3D additive metal printing. The specimens\u2019 acoustic behavior was analyzed with experimental measurements in single-layer and double-layer configurations. Then, the investigation was focused on the application of double-layer MPPs to the ceiling of an existing university lecture hall to enhance speech intelligibility. Numerical simulations were carried out using a full-spectrum wave-based method: a finite-difference time-domain (FDTD) code was chosen to better handle time-dependent signals as the verbal communication. The present work proposes a workflow to explore the suitability of a specific material to speech requirements. The measured specific impedance complex values allowed to derive the input data referred to MPPs in FDTD simulations. The outcomes of the process show the influence of the acoustic treatment in terms of reverberation time (T30 ) and sound clarity (C50 ). A systematic comparison with a standard geometrical acoustic (GA) technique is reported as well

    A Holocene tephra layer within coastal aeolian deposits north of Caleta Olivia (Santa Cruz Province, Argentina)

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    In this paper we illustrate the stratigraphy, geochronology, and geochemistry (major, minor, trace elements and Sr-isotopes) of a Holocene tephra layer found within coastal sedimentary deposits north of Caleta Olivia (Santa Cruz Province, Argentina). The stratigraphic succession comprises beach deposits with basal erosive surface resting on the local substrate (“Formación Patagonia”) followed by a poorly developed paleosoil. The paleosoil is covered by a lenticular fine grained (Mdφ: 5.2, 0.027 mm), well sorted (σφ: 1.2) volcanic ash layer and aeolian sands. The geochemical composition of shard fragments points to an origin from the Hudson volcano, located in the southern Andes, ca. 400 km to the west. The geochemistry, Sr-isotopes and the radiometric constraints (younger than the age of the underlying marine layer dated at ca. 4,100 a cal BP) further allow correlating this tephra with the so-called H2 eruption (ca. 3,900 a cal BP). This finding is of interest owing to the poor preservation potential of tephra within the Late Holocene sedimentary deposits of the Atlantic coast of Patagonia and represents the first finding of H2 eruption in this area, improving our knowledge of the dispersion of the fine-grained distal deposit of the Hudson volcanic explosive activity, thus allowing a better estimate of the eruptive dynamics and the risks associated with the Hudson volcano

    Fucoxantin: A Treasure from the Sea

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    The World Health Organization (WHO) estimates that 2.3 billion people will be overweight and 700 million obese in 2015. The reasons for this disastrous trend are attributed to the global tendency toward the reduced magnitude of exercise and physical activity and the increased dietary intake of fats, sugars and calories with reduced amount of vitamins and minerals. To prevent life-style-related diseases, like Metabolic Syndrome (MS), researchers’ attention is increasingly focusing on some of the so called “functional foods” which may be useful for their prevention and treatment. One of these functional ingredients is fucoxanthin (FX), a characteristic carotenoid present in edible brown seaweeds, such as Undaria pinnatifida (Wakame), Hijikia fusiformis (Hijiki), Laminaria japonica (Ma-Kombu) and Sargassum fulvellum. The increasing popularity of this molecule is certainly due to its anti-obesity effect, primarily detected by murine studies. These works revealed FX mediated induction of uncoupling protein-1 (UCP-1) in abdominal white adipose tissue (WAT) mitochondria, leading to the oxidation of fatty acids and heat production in WAT. Beyond this important role, in recent studies FX has shown a great antioxidant activity, anti-cancer, anti-diabetic and anti-photoaging properties. The aim of this review is to highlight the main effects of FX on human health

    Marine Bioactives: Pharmacological Properties and Potential Applications against Inflammatory Diseases

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    Inflammation is a hot topic in medical research, because it plays a key role in inflammatory diseases: rheumatoid arthritis (RA) and other forms of arthritis, diabetes, heart diseases, irritable bowel syndrome, Alzheimer’s disease, Parkinson’s disease, allergies, asthma, even cancer and many others. Over the past few decades, it was realized that the process of inflammation is virtually the same in different disorders, and a better understanding of inflammation may lead to better treatments for numerous diseases. Inflammation is the activation of the immune system in response to infection, irritation, or injury, with an influx of white blood cells, redness, heat, swelling, pain, and dysfunction of the organs involved. Although the pathophysiological basis of these conditions is not yet fully understood, reactive oxygen species (ROS) have often been implicated in their pathogenesis. In fact, in inflammatory diseases the antioxidant defense system is compromised, as evidenced by increased markers of oxidative stress, and decreased levels of protective antioxidant enzymes in patients with rheumatoid arthritis (RA). An enriched diet containing antioxidants, such as vitamin E, vitamin C, β-carotene and phenolic substances, has been suggested to improve symptoms by reducing disease-related oxidative stress. In this respect, the marine world represents a largely untapped reserve of bioactive ingredients, and considerable potential exists for exploitation of these bioactives as functional food ingredients. Substances such as n-3 oils, carotenoids, vitamins, minerals and peptides provide a myriad of health benefits, including reduction of cardiovascular diseases, anticarcinogenic and anti-inflammatory activities. New marine bioactives are recently gaining attention, since they could be helpful in combating chronic inflammatory degenerative conditions. The aim of this review is to examine the published studies concerning the potential pharmacological properties and application of many marine bioactives against inflammatory diseases

    Astrophysics with the Laser Interferometer Space Antenna

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    Laser Interferometer Space Antenna (LISA) will be a transformative experiment for gravitational wave astronomy as it will offer unique opportunities to address many key astrophysical questions in a completely novel way. The synergy with ground-based and other space-based instruments in the electromagnetic domain, by enabling multi-messenger observations, will add further to the discovery potential of LISA. The next decade is crucial to prepare the astrophysical community for LISA's first observations. This review outlines the extensive landscape of astrophysical theory, numerical simulations, and astronomical observations that are instrumental for modeling and interpreting the upcoming LISA datastream. To this aim, the current knowledge in three main source classes for LISA is reviewed: ultra-compact stellar-mass binaries, massive black hole binaries, and extreme or intermediate mass ratio inspirals. The relevant astrophysical processes and the established modeling techniques are summarized. Likewise, open issues and gaps in our understanding of these sources are highlighted, along with an indication of how LISA could help make progress in the different areas. New research avenues that LISA itself, or its joint exploitation with studies in the electromagnetic domain, will enable, are also illustrated. Improvements in modeling and analysis approaches, such as the combination of numerical simulations and modern data science techniques, are discussed. This review is intended to be a starting point for using LISA as a new discovery tool for understanding our Universe

    The autocorrelation-based analysis as a tool of sound perception in a reverberant field

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    A sound in a real space (e.g. a street or a room) is studied by acousticians as the relationship between an anechoic signal and the reverberant sound field. We define ‘anechoic signal’ a signal representing the pressure variation emitted by the sound source, while the ‘reverberant field’ is a field representing the sum of all the sound reflections of the environment in which the sound exists, delayed in time due to the positions of the sound source and the listener. The auditory ability of detecting a sound and assigning it to a source depends both on the anechoic signal and the reverberant sound field. This relationship has been analysed in acoustic literature using the autocorrelation properties of the anechoic signals and objective metrics of the sound field, the last ones being the ‘room criteria’ described in ISO 3382. In this context, the ‘effective duration’ of the autocorrelation function (τe) has been proposed as key factor to ‘preferred’ values of several room criteria in relation to different kind of music signals. Relying on some similarities between the definition of ‘auditory objects’ and the sound detection in a reverberant space, this paper proposes the use of τe as a potential tool to study and catalogue auditory objects
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