450 research outputs found

    The role of symbiosis in the evolution

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    Simbioza je udruženje dvije ili više različitih vrsta organizama. S obzirom na utjecaj na organizme koje uključuje može se podijeliti u tri kategorije: mutualizam, komenzalizam i parazitizam. U prirodi su simbiotski odnosi česti i u njih ulaze organizmi svih domena (uključujući i viruse) - arheje, eubakterije i pripadnici svih carstava eukariota. Prve ideje o simbiozi predstavio je švicarski botaničar Simon Schwendener u drugoj polovici 19. stoljeća na temelju proučavanja lišajeva. Simbiozu je prvi definirao Heinrich Anton de Bary kao pojavu u kojoj različiti organizmi žive zajedno. Početkom 20. stoljeća razvila se svijest o važnosti simbioze u evoluciji te o utjecaju koevolucije različitih organizama na njihovu specijaciju i koadaptaciju. U simbiozi različiti organizmi međusobno djeluju osiguravajući jedan drugome stanište, ekološku nišu, izvor nutrijenata i reprodukciju te ostvaruju nove metaboličke funkcije, morfološka svojstva i bihevioralne osobine. Rezultati toga su evolucijski napreci koje samostalne jedinke ne bi mogle postići. Tako je mikoriza, simbioza gljiva s korijenjem biljaka, omogućila izlazak biljnih organizama na kopno, ključan za razvoj života kakav danas poznajemo. U simbiozi osobine jedne jedinke često nadomještaju nedostatke one druge. Najbolji primjer za to je da je život neobičnog dubokomorskog cjevaša, s potpunim nedostatkom probavnog sustava, omogućen u ekstremnim uvjetima dubokomorskih hidrotermalnih izvora zbog simbioze sa sumpor-oksidirajućim kemosintetskim bakterijama.Symbiosis is an association of two or more different species. Considering the impact on the organisms it includes, symbiosis can be divided into three categories: mutualism, commensalism and parasitism. Symbiotic relationships are common and they cover all domains of organisms (including viruses) - archaea, eubacteria and all kingdoms of eukaryotes. The first idea of symbiosis was presented by the Swiss botanist Simon Schwendener in the second half of the 19th century, based on the study of lichens. Symbiosis was first defined by Heinrich Anton de Bary as a phenomenon of different organisms living together. At the beginning of the 20th century, scientists became aware of the importance of symbiosis in evolution and the influence coevolution had on speciation and coadaptation of different organisms. In symbiosis, different organisms provide each other habitat, ecological niche, nutrients or reproduction and they generate new metabolic functions, morphological characteristics and behavioral traits. The result is evolutionary progress that independent individuals could not achieve. In such a way, mycorrhiza, a symbiosis of fungi with plant roots, enabled the colonization of terrestrial habitat by plants, which is essential for life as we know it. In symbiosis, the features of one species often cover the deficiencies of the other. The best example for that is the life of an unusual tubeworm, which lacks a digestive system, that was enabled in extreme habitat of deep-sea hydrothermal vents due to its symbiosis with sulfur-oxidizing chemosynthetic bacteria

    A WORLDWIDE 3D GCP DATABASE INHERITED FROM 20 YEARS OF MASSIVE MULTI-SATELLITE OBSERVATIONS

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    Abstract. High location accuracy is a major requirement for satellite image users. Target performance is usually achieved thanks to either specific on-board satellite equipment or an auxiliary registration reference dataset. Both methods may be expensive and with certain limitations in terms of performance. The Institut national de l'information géographique et forestière (IGN) and Airbus Defence and Space (ADS) have worked together for almost 20 years, to build reference data for improving image location using multi-satellite observations. The first geometric foundation created has mainly used SPOT 5 High Resolution Stereoscopic (HRS) imagery, ancillary Ground Control Points (GCP) and Very High Resolution (VHR) imagery, providing a homogenous location accuracy of 10m CE90 almost all over the world in 2010.Space Reference Points (SRP) is a new worldwide 3D GCP database, built from a plethoric SPOT 6/7 multi-view archive, largely automatically processed, with cloud-based technologies. SRP aims at providing a systematic and reliable solution for image location (Unmanned Aerial Vehicle, VHR satellite imagery, High Altitudes Pseudo-Satellite…) and similar topics thanks to a high-density point distribution with a 3m CE90 accuracy.This paper describes the principle of SRP generation and presents the first validation results. A SPOT 6/7 smart image selection is performed to keep only relevant images for SRP purpose. The location of these SPOT 6/7 images is refined thanks to a spatiotriangulation on the worldwide geometric foundation, itself improved where needed. Points making up the future SRP database are afterward extracted thanks to classical feature detection algorithms and with respect to the expected density. Different filtering methods are applied to keep the best candidates. The last step of the processing chain is the formatting of the data to the delivery format, including metadata. An example of validation of SRP concept and specification on two tests sites (Spain and China) is then given. As a conclusion, the on-going production is shortly presented

    The P2Y12 receptor induces platelet aggregation through weak activation of the αIIbβ3 integrin – a phosphoinositide 3-kinase-dependent mechanism

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    AbstractHigh concentrations of adenosine-5′-diphosphate ADP are able to induce partial aggregation without shape change of P2Y1 receptor-deficient mouse platelets through activation of the P2Y12 receptor. In the present work we studied the transduction pathways selectively involved in this phenomenon. Flow cytometric analyses using R-phycoerythrin-conjugated JON/A antibody (JON/A-PE), an antibody which recognizes activated mouse αIIbβ3 integrin, revealed a low level activation of αIIbβ3 in P2Y1 receptor-deficient platelets in response to 100 μM ADP or 1 μM 2MeS-ADP. Adrenaline induced no such activation but strongly potentiated the effect of ADP in a dose-dependent manner. Global phosphorylation of 32P-labeled platelets showed that P2Y12-mediated aggregation was not accompanied by an increase in the phosphorylation of myosin light chain (P20) or pleckstrin (P47) and was not affected by the protein kinase C (PKC) inhibitor staurosporine. On the other hand, two unrelated phosphoinositide 3-kinase inhibitors, wortmannin and LY294002, inhibited this aggregation. Our results indicate that (i) the P2Y12 receptor is able to trigger a P2Y1 receptor-independent inside-out signal leading to αIIbβ3 integrin activation and platelet aggregation, (ii) ADP and adrenaline use different signaling pathways which synergize to activate the αIIbβ3 integrin, and (iii) the transduction pathway triggered by the P2Y12 receptor is independent of PKC but dependent on phosphoinositide 3-kinase

    Traumatic vessel injuries initiating hemostasis generate high shear conditions

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    Blood flow is a major regulator of hemostasis and arterial thrombosis. The current view is that low and intermediate flows occur in intact healthy vessels, whereas high shear levels (>2000 s−1) are reached in stenosed arteries, notably during thrombosis. To date, the shear rates occurring at the edge of a lesion in an otherwise healthy vessel are nevertheless unknown. The aim of this work was to measure the shear rates prevailing in wounds in a context relevant to hemostasis. Three models of vessel puncture and transection were developed and characterized for a study that was implemented in mice and humans. Doppler probe measurements supplemented by a computational model revealed that shear rates at the edge of a wound reached high values, with medians of 22 000 s−1, 25 000 s−1, and 7000 s−1 after puncture of the murine carotid artery, aorta, or saphenous vein, respectively. Similar shear levels were observed after transection of the mouse spermatic artery. These results were confirmed in a human venous puncture model, where shear rates in a catheter implanted in the cubital vein reached 2000 to 27 000 s−1. In all models, the high shear conditions were accompanied by elevated levels of elongational flow exceeding 1000 s−1. In the puncture model, the shear rates decreased steeply with increasing injury size. This phenomenon could be explained by the low hydrodynamic resistance of the injuries as compared with that of the downstream vessel network. These findings show that high shear rates (>3000 s−1) are relevant to hemostasis and not exclusive to arterial thrombosis

    The use of tire rubber in the production of high-performance concrete

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    The advances in concrete technology lead to the search for alternative materials that provide improvements in concrete properties while at the same time collaborating with sustainable practices in construction. In this study, the influence of the incorporation of waste tire rubber on the mechanical properties of high-performance concrete was discussed. The waste rubber from the tire retreading process was used in partial substitution of the fine aggregate (sand) in the percentages of 7.5%, 15% and 30% with respect to the mass of the sand. For the characterization of the concrete, the following tests were carried out: water absorption, void index, specific density, compressive strength, flexural tensile strength, modulus of elasticity and microscopy analysis. The incorporation of rubber as aggregate in high-performance concrete proved to be promising for the production of a structural concrete with special characteristics, besides collaborating with the proper disposal of waste tires651110114sem informaçã

    Local carrier recombination and associated dynamics in m-plane InGaN/GaN quantum wells probed by picosecond cathodoluminescence

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    Research data in support of the publication "Local carrier recombination and associated dynamics in m-plane InGaN/GaN quantum wells probed by picosecond cathodoluminescence". We have included the original data (tab-separated text files) as plotted for the quantum wells, measured by spatially- and time-resolved cathodoluminescence

    Caracterização climática da área petrolífera de Buracica, Município de Alagoinhas, Estado da Bahia, como subsídio para ações de recuperação de áreas degradadas.

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    O presente trabalho, focado na caracterização climática da localidade de Buracica, município de Alagoinhas, Estado da Bahia, se integra ao diagnóstico do meio físico da referido sítio que, por sua vez, compõe os estudos preliminares para subsidiar o projeto: "Elaboração de diagnóstico e plano de recuperação da área degradada (voçoroca) da estação de Camboatá no campo de exploração de petróleo de Buracica, município de Alagoinhas, BA", objeto da Cooperação técnica entre a Embrapa Solos e a PUC-Rio, sob a demanda e o patrocínio da PETROBRAS AS/UN-BA

    Imaging thrombosis with 99mTc-labeled RAM.1-antibody in vivo.

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    Platelets play a major role in thrombo-embolic diseases, notably by forming a thrombus that can ultimately occlude a vessel. This may provoke ischemic pathologies such as myocardial infarction, stroke or peripheral artery diseases, which represent the major causes of death worldwide. The aim of this study was to evaluate the specificity of radiolabeled Rat-Anti-Mouse antibody (RAM.1).We describe a method to detect platelets by using a RAM.1 coupled with the chelating agent hydrazinonicotinic acid (HYNIC) conjugated toWe demonstrated a quick and strong affinity of the radiolabeled RAM.1 for the platelet thrombus. Results clearly demonstrated the ability of this radioimmunoconjugate for detecting thrombi from 10 min post injection with an exceptional thrombi uptake. Using FeClThanks to the high sensitivity of SPECT, we provided evidence that [journal articleresearch support, non-u.s. gov't2018 062018 03 17importe

    Experiencias y comprensiones sobre violencias contra mujeres jóvenes : relatos de mujeres entre 18 y 29 años en la ciudad de Bogotá

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    La violencia contra mujeres jóvenes es una problemática social que ha incrementado en los últimos años, ya que las mujeres entre los 18 y 29 años son las víctimas más frecuentes de violencia basada en género. Para el año 2013, en Colombia el más alto número de mujeres asesinadas se encontraban entre los 15 y 29 años. Sin embargo, es notable el bajo índice de denuncia de hechos de violencia contra mujeres en esta etapa del ciclo vital. Por tanto, esta investigación indaga sobre experiencias y comprensiones relativas a las violencias contra las mujeres relatadas por mujeres jóvenes entre 18 y 29 años en la ciudad de Bogotá. Para el análisis de los relatos se acude a la perspectiva de género y a categorías como subjetividad femenina, violencia contra mujeres y ámbito público-privado. Se utiliza una metodología con enfoque cualitativo y se diseña un cuestionario con 24 preguntas que fue aplicado a 40 mujeres de todos los estratos socioeconómicos, divididas en dos rangos de edades: entre 18 y 23 años, y entre 24 y 29 años, posteriormente, se realizó un grupo focal con seis mujeres. Se identifica que los tipos de violencia psicológica, sexual y física son las que más afectan a las mujeres jóvenes. Igualmente se hace evidente que, si bien las jóvenes reconocen y son conscientes sobre situaciones y tipos de violencias en lugares públicos y privados en los que se sienten o están efectivamente en riesgo, la persistencia de roles estereotipados de género coexisten con discursos contradictorios de contenido relativamente emancipatorio respecto a condiciones históricas y culturales que configuran sus subjetividades, lo cual incide de manera negativa respecto a prácticas de autoprotección y de denuncia.Violence against young women is a social issue that has increased in the last few years, women between the ages of 18 and 29 are the most frequent victims of gender-based violence. In 2013, the highest number of murdered women in Colombia was between the ages of 15 and 29. However the report rate of these violent crimes against women at this stage of their life cycle is notably low. Therefore, this investigation is about experiences related to violence against women, described by young women between the ages of 18 and 29 in the city of Bogota. For the analysis of the stories, we resort to gender perspective and categories like feminine subjectivity, violence against women, and the public-private sector. We opted for a method with a qualitative focus and designed a questionnaire with 24 questions that was presented to 40 women of all the socioeconomic levels, divided in two age groups: between 18 and 23, and between 24 and 29, afterwards we formed a focal group of six women. We identified that the types of violence that most affects young women are psychological, sexual, and physical. Likewise, it s evident that if young women recognize and are conscious about situations and types of violence in public and private places in which they feel or are in fact at risk, the persistence of stereotypical gender roles coexist with contradictory speeches of relatively emancipatory content regarding historical and cultural conditions that configure their subjectivity, which influences them in a negative way regarding practices of autoprotection and reporting of crimes.Psicólogo (a)Pregrad
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