335 research outputs found
Les industries lithiques de la grotte de la Terrasse à Montmaurin (Haute-Garonne)
Le site préhistorique dit de « La Terrasse » fait partie du complexe des grottes de Montmaurin (Haute-Garonne) ayant livré des industries du Paléolithique inférieur. Il a été fouillé sous la direction de L. Méroc de 1946 à 1961 avec les premières techniques « modernes » de fouille. Le site comporte deux couches archéologiques principales, datables de l’Acheuléen supérieur. L’outillage, obtenu essentiellement à partir de quartzite local, fait une large place aux galets aménagés s.l. : choppers et chopping-tools, ainsi qu’aux bifaces. La couche 2, la plus ancienne, serait datable du Mindel-Riss ou plus probablement d’un inter-Riss, la couche 1 pourrait témoigner du retour de conditions climatiques plus rigoureuses ayant marqué le choix des outils.The prehistoric site of “La Terrasse” belongs to the complex of Montmaurin (Haute-Garonne, France). Industries from lower Palaeolithic were found and diggings carried out by L. Méroc from1946 to 1961, with “modern” methods. The site shows two main archaeological beds, dated from higher Acheulean. The tools, mainly made of local quartzite, shows a great quantity of choppers, chopping-tools and bifaces. The bed 2, the older, could belong to Mindel-Riss or more probably to inter-Riss. The bed 1 could correspond to a new cold episode which guides the choice of tools
Les industries lithiques de la grotte de la Terrasse à Montmaurin (Haute-Garonne)
Le site préhistorique dit de « La Terrasse » fait partie du complexe des grottes de Montmaurin (Haute-Garonne) ayant livré des industries du Paléolithique inférieur. Il a été fouillé sous la direction de L. Méroc de 1946 à 1961 avec les premières techniques « modernes » de fouille. Le site comporte deux couches archéologiques principales, datables de l’Acheuléen supérieur. L’outillage, obtenu essentiellement à partir de quartzite local, fait une large place aux galets aménagés s.l. : choppers et chopping-tools, ainsi qu’aux bifaces. La couche 2, la plus ancienne, serait datable du Mindel-Riss ou plus probablement d’un inter-Riss, la couche 1 pourrait témoigner du retour de conditions climatiques plus rigoureuses ayant marqué le choix des outils.The prehistoric site of “La Terrasse” belongs to the complex of Montmaurin (Haute-Garonne, France). Industries from lower Palaeolithic were found and diggings carried out by L. Méroc from1946 to 1961, with “modern” methods. The site shows two main archaeological beds, dated from higher Acheulean. The tools, mainly made of local quartzite, shows a great quantity of choppers, chopping-tools and bifaces. The bed 2, the older, could belong to Mindel-Riss or more probably to inter-Riss. The bed 1 could correspond to a new cold episode which guides the choice of tools
Viability of using enamel and dentin from bovine origin as a substitute for human counterparts in an intraoral erosion model
This study ascertained whether under dental erosion models that closely mimics the real-life situation enamel and root dentin from bovine origin would be reliable substitutes for human counterparts. Through a 2x2 crossover design, in a first trial, 14 volunteers wore a palatal device containing slabs of bovine and human enamel. Half of the participants ingested (4x daily, for 10 days) orange juice first, crossing over to mineral water, while the remainder received the reverse sequence. In a second trial, volunteers wore devices with slabs of bovine and human root dentin. Except for the duration of each intraoral phase, which lasted 2 rather 10 days, the experiment with root dentin run exactly as for enamel. Dental substrates were analyzed for surface microhardness. Two-way ANOVAs (α=0.05) indicated no difference between the microhardness values recorded for human and bovine enamel (p=0.1350), but bovine root dentin had lower microhardness compared to its human counterpart (p=0.0432). While bovine enamel can reliably substitute its human counterpart in in situ dental erosion models, bovine root dentin does not seem to be a viable alternative to the corresponding human tissue.Este estudo visou avaliar, sob um modelo de erosão dental que se aproxima da realidade clínica, se o esmalte e a dentina radicular bovinos seriam substitutos viáveis aos correspondentes substratos de origem humana. De acordo com um delineamento crossover 2x2, 14 voluntários utilizaram dispositivos palatinos contendo fragmentos de esmalte humano e bovino. Metade dos participantes ingeriu suco de laranja (4x/dia, por 10 dias) e, a seguir, alternou para a ingestão de água mineral, enquanto os demais voluntários receberam a seqüência reversa. Em um segundo experimento, os sujeitos da pesquisa fizeram uso do dispositivo palatino contendo fragmentos de dentina radicular bovina e humana. Exceto pela duração de cada uma das duas fases experimentais (2 ao invés de 10 dias), utilizou-se o mesmo protocolo empregado no estudo em que se comparou o esmalte. Os substratos dentais foram avaliados quanto a sua microdureza superficial. ANOVAs a dois critérios (α=0,05) não indicaram diferença entre os valores de microdureza observados para o esmalte humano e bovino (p=0,1350), porém a dentina radicular apresentou microdureza inferior à humana (p=0,0432). Enquanto o esmalte bovino é um substituto fidedigno do substrato humano em modelos in situ de erosão dental, a dentina radicular bovina não parece ser uma alternativa viável ao tecido humano correspondente.The authors are especially grateful for the valuable participation and cooperation of the volunteers. Thanks are also due to Patricia Marchi, for her technical assistance, and to the Ethylene Oxide Sterilization Center of the Clinical Hospital of the School of Medicine of Ribeirão Preto (USP), for sterilizing the dental slabs. The State of São Paulo Research Foundation (FAPESP, grant #05/01515-8) is acknowledged for providing financial assistance in the form of a scholarship to the first author. This research was partially funded by a grant from the First Projects Program (MCT/CNPq-FAPESP, grant #06/60356-0)
Water resources deterioration and its impact on human health
The objective of the study is to analyse the actual availability of water resources and its impact on human health deterioration. The following aspects were studied: (a) human activities and environmental deterioration; (b) statistics on the availability and demand of water resources; (c) urban and industry wastes as sources of water resources contamination; and (d) deleterious effect of contaminated water on human health. Statistical data on the impact of contaminated water on human health and the increasing demand of water resources are alarming. It is paramount that modern generations develop an environmental awareness to avoid overstressing water systems, as predicted to come about in the very near future.O objetivo do trabalho é analisar dados sobre a real disponibilidade dos recursos hídricos e o reflexo de sua degradação na saúde humana. Visa a acompanhar o crescimento da degradação ambiental nos últimos anos e o fornecimento de dados recentes e confiáveis sobre o tema. Foram abordados os seguintes aspectos: (a) atividades antrópicas e degradação ambiental; (b) estatísticas da disponibilidade e demanda dos recursos hídricos; (c) despejos urbanos e industriais como fontes de contaminação dos recursos hídricos; (d) efeitos deletérios da água contaminada sobre o organismo humano. São alarmantes os valores estatísticos relacionados aos efeitos da água contaminada sobre a saúde humana e ao aumento na demanda dos recursos hídricos. É de importância fundamental a tomada de uma consciência ambientalista por parte das gerações atuais a fim de se evitar o estresse máximo do sistema hídrico, cuja efetivação está prevista para um futuro muito próximo
H I in group interactions: HCG 44
Extending deep observations of the neutral atomic hydrogen (HI) to the
environment around galaxy groups can reveal a complex history of group
interactions which is invisible to studies that focus on the stellar component.
Hickson Compact Group 44 (HCG 44) is a nearby example and we have combined HI
data from the Karoo Array Telescope, Westerbork Synthesis Radio Telescope, and
Arecibo Legacy Fast ALFA survey, in order to achieve high column density
sensitivity (N_HI < 2x10^18 cm^-2) to the neutral gas over a large
field-of-view beyond the compact group itself. We find the giant HI tail north
of HCG 44 contains 1.1x10^9 M_Sun of gas and extends 450 kpc from the compact
group: twice as much mass and 33% further than previously detected. However,
the additional gas is still unable to account for the known HI deficiency of
HCG 44. The tail likely formed through a strong tidal interaction and HI clouds
in the tail have survived for 1 Gyr or more after being stripped. This has
important implications for understanding the survival of neutral clouds in the
intragroup and circumgroup medium, and we discuss their survival in the context
of simulations of cold gas in hot halos. HCG 44 is one of a growing number of
galaxy groups found to have more extended HI in the intragroup and circumgroup
medium than previously measured. Our results provide constraints for
simulations on the properties of galaxy group halos, and reveal a glimpse of
what will be seen by future powerful HI telescopes and surveys.Comment: 12 pages, 6 figures. Accepted for publication in MNRA
A comunicação através da arte: construção da maquete da Serra do Espinhaço Meridional como recurso interdisciplinar e didático
Este trabalho oriundo do projeto de divulgao cientfica GAIA (Geocincias, Arte, Interdisciplinaridade e Aprendizagem) que, usando como base os Parmetros Curriculares Nacionais, construiu uma maquete da Serra do Espinhao Meridional voltada para prticas ldicas para o Ensino Fundamental e Mdio. A maquete representa um importante recurso de comunicao e forte potencial didtico para a anlise integrada da paisagem e compreenso do espao geogrfico num processo de ensino-aprendizagem, sendo a Cartografia a cincia que norteia o caminho sobre a importncia e os mtodos de representao do espao. Atravs de pesquisa bibliogrfica e atividades de campo realizados na poro Meridional da Serra do Espinhao, foi possvel refletir e desenvolver uma prtica pedaggica ldica no formal e complementar para o entendimento do espao geogrfico no qual estudantes do ensino fundamental e mdio residem, como o caso de Diamantina em relao a Serra. A elaborao da maquete propiciou no s uma importante noo da abrangncia territorial da Serra do Espinhao Meridional, como tambm uma absoro de informaes interdisciplinares, devido aos diferentes elementos nela representados, podendo ser utilizada no ensino da Geografia alm de outras disciplinas em todos os ciclos de ensino
Design and Prototyping of a Nanosatellite Laser Communications Terminal for the Cubesat Laser Infrared CrosslinK (CLICK) B/C Mission
The CubeSat Laser Infrared CrossLink (CLICK) mission goal is to demonstrate a low cost, high data rate optical transceiver terminal with fine pointing and precision time transfer in aleq1.5U form factor. There are two phases to the technology demonstration for the CLICK mission: CLICK-A downlink, and then CLICK-B/C crosslink and downlink. The topic of this paper is the design and prototyping of the laser communications (lasercom) terminal for the CLICK-B/C phase. CLICK B/C consists of two identical 3U CubeSats from Blue Canyon Technologies that will be launched together in Low Earth Orbit to demonstrate crosslinks at ranges between 25 km and 580 km with a data rate of ≥20 Mbps and a ranging capability better than 0.5 m. Downlinks with data rates of ≥10 Mbps will also be demonstrated to the Portable Telescope for Lasercom (PorTeL) ground station. Link analysis using current parameters & experimental results predicts successful crosslink & downlink communications and ranging. Moreover, closed-loop 3σ fine pointing error is predicted to be less than 39.66 μrad of the 121.0 μrad 1/e² transmit laser divergence. The status of the payload EDU and recent developments of the optomechanical and thermal designs are discussed
Development of CubeSat Spacecraft-to-Spacecraft Optical Link Detection Chain for the CLICK B/C Mission
The growing interest in and expanding applications of small satellite constellation networks necessitates effective and reliable high-bandwidth communication between spacecraft. The applications of these constellations (such as navigation or imaging) rely on the precise measurement of timing offset between the spacecraft in the constellation. The CubeSat Laser Infrared CrosslinK (CLICK) mission is being developed by the Massachusetts Institute of Technology (MIT), the University of Florida (UF), and NASA Ames Research Center. The second phase of the mission (CLICK-B/C) will demonstrate a crosslink between two CubeSats (B and C) that each host a \u3c 2U laser communication payload. The terminals will demonstrate full-duplex spacecraft-to-spacecraft communications and ranging capability using commercial components. As part of the mission, CLICK will demonstrate two-way time-transfer for clock synchronization and data transfer at a minimum rate of 20 Mbps over separation distances ranging from 25 km to 580 km. The payloads of CLICK B and C include a receiver chain with a custom photodetector board, a Time-to-Digital Converter (TDC), a Microchip Chip-Scale Atomic Clock (CSAC), and a field-programmable gate array (FPGA). The payloads can measure internal propagation delays of the transmitter and the receiver, and cancel environmental effects impacting timing accuracy. The photodetector board is 2.5 cm x 2.5 cm and includes an avalanche photodiode (APD) and variable-gain amplifiers through which the detected signal is conditioned for the TDC to be time-stamped. This design has been developed from the UF and NASA Ames CubeSat Handling Of Multisystem Precision Time Transfer (CHOMPTT) project and associated MOCT (Miniature Optical Communication Transceiver) demonstration. The TDC samples the signal at four points: twice on the rising edge at set thresholds, and twice at the falling edge at those same thresholds. These four time-offset samples are sent to the FPGA, which combines the measurements for a reported timestamp of the detected laser pulse. These timestamps can then be used in a pulse-position modulation (PPM) demodulation scheme to receive data at up to 50 Mbps, to calculate range down to 10 cm, and for precision time-transfer with \u3c 200 ps resolution. In this paper, we will discuss the designed capabilities and noise performance of the CLICK TDC-based optical receiver chain
Hanseníase Lepromatosa: Relato de um Caso do Tipo Histióide-Símile.
Histoid leprosy, described by Wade in 1963, represents an atypical variant of lepromatous leprosy, with its own clinical and pathological features. In the past, it was considered a marker of drug resistance and relapse. It presents as keloid-like plaque or nodular lesions. Optical microscopy shows few foamy macrophages and numerous alcohol-acid-resistant bacilli and an infiltrate composed predominantly of spindle cells, which can mimic fibrohistiocytic neoplasms. We report a case of lepromatous leprosy with lesions clinically compatible with the histoid variant in order to demonstrate and reinforce the clinical polymorphism of this type of Hansen’s disease and raise awareness for the need of an early diagnosis and treatment, therefore with the interruption of the transmission chain and reduction of the occurrence of irreversible leprosy-related disability.A hanseníase históide representa uma forma atípica de apresentação da hanseníase virchowiana, descrita por Wade em 1963, com características clínicas e anatomopatológicas próprias, que no passado era considerada um marcador de resistência medicamentosa e recidiva. Clinicamente caracteriza-se por placas ou nodulos de aspecto queloidiforme. À microscopia óptica nota-se infiltrado predominantemente constituído por células fusiformes que por vezes simula neoplasia fibrohistiocítica, associada a poucos macrófagos espumosos e numerosos bacilos álcool-ácido-resistentes. Relata-se um caso de hanseníase virchowiana com lesões clinicamente compatíveis com a forma históide, a fim de demonstrar e reforçar o seu grande polimorfismo clínico e a importância do seu conhecimento para diagnóstico e tratamento precoce, para interromper a cadeia de transmissão e diminuir a ocorrência de incapacidades irreversíveis causadas pela doença
- …