563 research outputs found
Shine on you crazy diamond: Symbolism and social use of fluorite ornaments in Iberia’s late prehistory
Fluorite ornaments have been recorded in different sites of Europe since Upper Paleolithic. Due to its visual appearance and physical properties, some translucent or transparent mineralogies like fluorite were searched for or casually acquired by late prehistory’s human communities. After intensive research on archaeological contexts from the Iberian Peninsula with personal ornaments from 4th to 2nd millennia BCE, we have recently identified and characterized for the first time an important number of fluorite ornaments, confronting a previous background where little attention was paid. Our work has been carried out in different archaeological collections and museums from the whole Iberian Peninsula by non-destructive techniques (Raman spectroscopy, portable X-ray fluorescence (p-XRF) and X-ray Diffraction (XRD), that revealed the nature of fluorite ornaments and points to its consideration as scarce and highly symbolic items during late prehistory. A total of 36 fluorite beads from 23 sites are here recorded and studied, many of them unpublished or wrong catalogued as other mineralogies. These adornments could have important roles in trade and use among the communities of Iberia from the 4th millennium BCE onwards, because of their scarcity and its recurrent association with important funerary complex and exotic materials. Fluorite ornaments could have been significant and special symbols in the development of new and exclusive raw materials in the context of increasing social complexity and inequality
Distribución y consumo de cuentas de fluorita y translúcidas en la península ibérica del VI al II milenios ANE
Translucent minerals were valued in prehistoric societies
for their rarity and socially used as highly symbolic elements.
This work addresses the use and nature of Iberian translucent
beads. We present the results of chemical (Raman spectroscopy,
portable X-ray fluorescence, X-ray diffraction and
visible (Vis)/near-infrared (NIR) spectroscopy) and contextual
analyses and provide a review of the archaeological
literature on the manufacture and use of translucent items
during Iberian Late Prehistory. A total of 54 translucent beads
from 47 sites, primarily burials, were analyzed; 33 were
made from fluorite, while the remaining 21 were made of
diverse translucent minerals (calcite, quartz and different
silicates). The scarcity of translucent items in the archaeological
record, the regional and supraregional scale of its
exchange, and its recursive association to other valuables in
singular contexts reinforces the idea that their owners/wearers
enjoyed a high status.info:eu-repo/semantics/publishedVersio
An Arduino-Based Talking Calorimeter for Inclusive Lab Activities
UID/QUI/50006/2019 POCI-01-0145-FEDER-007265 PEest/UID/CEC/04516/2019 02/2018/ARNI (International Academic Mobility Program.PMAI) 10/2018/PROPPIT (Course Completion Work Program.PROTCC)This work describes a simple talking calorimeter for the visually impaired based on the Arduino Uno without any shield. An electronic interface was designed using a Wheatstone bridge, a thermistor, or an operational amplifier (opamp). The temperature values are communicated by a loudspeaker connected to pulse-width modulation (PWM) digital output pins 3 and 11 of the Arduino Uno. The system is based on the Talkie library for Arduino Uno. This library was developed using Linear Predictive Coding and includes about 1000 English words. Two new Talkie libraries were constructed, one for Portuguese and another for German. This device can be easily implemented in any teaching laboratory with extremely reduced costs.publishersversionpublishe
THE STUDY OF SWIMMERS’S HAND AND FOREARM USING COMPUTATIONAL FLUID DYNAMICS
Computational Fluid Dynamics has been widely used in biomechanics studies applied to medicine and sport. In this study we developed a 3-D model for swimmer’s hand/forearm
forces using Computational Fluid Dynamics. Models used in the simulations were created in CAD, based on realistic dimensions of a right adult human hand/forearm. The
governing system of equations considered was the incompressible Reynolds averaged Navier-Stokes equations implemented with Fluent® code. The drag coefficient was the
main responsible for propulsion, with a maximum value of force propulsion corresponding to a pitch angle of 90º. The lift coefficient seemed to play a less important role in the
generation of propulsive force with pitch angles of 0º and 90º but it is important with a pitch angle of 45º. It was demonstrated the relevance of applying CFD in the propulsive
force measurements, using a more realistic model of a human segment
Suporte social em crianças e jovens com PHDA e em obesos: análise comparativa
[resumo][abstract
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CLEC-2 and Syk in the megakaryocytic/platelet lineage are essential for development
The C-type lectin receptor CLEC-2 signals through a pathway that is critically dependent on the tyrosine kinase Syk. We show that homozygous loss of either protein results in defects in brain vascular and lymphatic development, lung inflation and perinatal lethality. Furthermore, we find that conditional deletion of Syk in the haematopoietic lineage, or conditional deletion of CLEC-2 or Syk in the megakaryocyte/platelet lineage, also causes defects in brain vascular and lymphatic development, although the mice are viable. In contrast, conditional deletion of Syk in other haematopoietic lineages had no effect on viability or brain vasculature and lymphatic development. We show that platelets, but not platelet releasate, modulate the migration and intercellular adhesion of lymphatic endothelial cells through a pathway that is dependent on CLEC-2 and Syk. These studies demonstrate that megakaryocyte/platelet expression of CLEC-2 and Syk is required for normal brain vasculature and lymphatic development and that platelet CLEC-2 and Syk directly modulate lymphatic endothelial cell behaviour in vitro
Stellar Astrophysics and Exoplanet Science with the Maunakea Spectroscopic Explorer (MSE)
The Maunakea Spectroscopic Explorer (MSE) is a planned 11.25-m aperture
facility with a 1.5 square degree field of view that will be fully dedicated to
multi-object spectroscopy. A rebirth of the 3.6m Canada-France-Hawaii Telescope
on Maunakea, MSE will use 4332 fibers operating at three different resolving
powers (R ~ 2500, 6000, 40000) across a wavelength range of 0.36-1.8mum, with
dynamical fiber positioning that allows fibers to match the exposure times of
individual objects. MSE will enable spectroscopic surveys with unprecedented
scale and sensitivity by collecting millions of spectra per year down to
limiting magnitudes of g ~ 20-24 mag, with a nominal velocity precision of ~100
m/s in high-resolution mode. This white paper describes science cases for
stellar astrophysics and exoplanet science using MSE, including the discovery
and atmospheric characterization of exoplanets and substellar objects, stellar
physics with star clusters, asteroseismology of solar-like oscillators and
opacity-driven pulsators, studies of stellar rotation, activity, and
multiplicity, as well as the chemical characterization of AGB and extremely
metal-poor stars.Comment: 31 pages, 11 figures; To appear as a chapter for the Detailed Science
Case of the Maunakea Spectroscopic Explore
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Thermochemical and Theoretical Studies of Dimethylpyridine-2,6-dicarboxylate and Pyridine-2,3-, Pyridine-2,5-, and Pyridine-2,6-dicarboxylic Acids
Article discussing thermochemical and theoretical studies of dimethylpyridine-2,6-dicarboxylate and pyridine-2,3-, pyridine-2,5- and pyridine-2,6-dicarboxylic acids
Quimissorção de cátions divalentes em sílica gel modificada com ácido tioglicólico: a influência do pH e força iônica
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