988 resultados para charge transport


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Inorganic phosphate (Pi) and zinc (Zn) are two essential nutrients for plant growth. In soils, these two minerals are either present in low amounts or are poorly available to plants. Consequently, worldwide agriculture has become dependent on external sources of Pi and Zn fertilizers to increase crop yields. However, this strategy is neither economically nor ecologically sustainable in the long term, particularly for Pi, which is a non-renewable resource. To date, research has emphasized the analysis of mineral nutrition considering each nutrient individually, and showed that Pi and Zn homeostasis is highly regulated in a complex process. Interestingly, numerous observations point to an unexpected interconnection between the homeostasis of the two nutrients. Nevertheless, despite their fundamental importance, the molecular bases and biological significance of these interactions remain largely unknown. Such interconnections can account for shortcomings of current agronomic models that typically focus on improving the assimilation of individual elements. Here, current knowledge on the regulation of the transport and signalling of Pi and Zn individually is reviewed, and then insights are provided on the recent progress made towards a better understanding of the Zn-Pi homeostasis interaction in plants.

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The widespread use of abdominal imaging technologies has led to an increase in the incidental finding of liver tumors. Most of these lesions are asymptomatic and will not require any treatment. With the use of contrast-enhanced radiological studies, most of the tumors can be reliably diagnosed by non-invasive means. In case of diagnostic uncertainty, patients should not undergo percutaneous biopsy but rather complete resection of the lesion for an unequivocal diagnosis. Such pathologies must be taken charge of in centers with expertise by interdisciplinary teams.

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Diagnostic and treatment management of prostate cancer at its initial stage continues to raise important debates within the involved medical community. To establish a protocol for active surveillance, a validated option in specific conditions of localised prostate cancer management for eight years, is a unique opportunity to gather different specialists in this field. This paper presents this concept.

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This study examines how MPEG-2 Transport Stream, used in DVB-T video transmission, can be reliably and efficiently transferred to remote locations over an MPLS network. All the relevant technologies used in this scenario are also discussed in the study. This study was done for Digita Oy, which is a major radio and television content distributor in Finland. The theoretical part of the study begins with the introduction to MPLS technology and continues with explanation of IP Multicast and its components. The fourth section discusses MPEG-2 and the formation and content of MPEG-2 Transport Stream. These technologies were studied in relevant literature and RFC documentation. After the theoretical part of the study, the test setup and the test cases are presented. The results of the test cases, and the conclusions that can be drawn based on them, are discussed in the last section of the study. The tests showed that it is possible to transfer digital video quite reliably over an MPLS network using IP Multicast. By configuring the equipment correctly, the recovery time of the network in case of a failure can be shortened remarkably. Also, the unwanted effect of other traffic on the critical video traffic can be eliminated by defining the Quality of Service parameters correctly. There are, however, some issues that need to be tested further before this setup can be used in broadcast networks. Reliable operation of IP Multicast and proper error correction are the main subjects for future testing.

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Objectif : La prise en charge des patients avec hyperglycémie en soins aigus estdifficile et les erreurs de prescription d'insuline sont fréquentes. Notre objectifest de promouvoir l'évolution des pratiques vers une gestion efficace et sécuritairede l'hyperglycémie.Matériels et méthodes : Création d'un programme de formation structuré pourla gestion de l'hyperglycémie en soins aigus. Ce programme est le produit dumétissage entre le modèle de l'accompagnement thérapeutique et la systémiquedu management. Il vise l'acquisition d'une métacognition pour une réflexiontransversale face à l'hyperglycémie. Les objectifs spécifiques sont : comprendreles particularités de l'hyperglycémie en aigu ; gérer le basal/bolus ; argumenterle choix thérapeutique ; s'approprier l'outil sécuritaire d'aide à l'insulinothérapie ;anticiper la sortie du patient. Une analyse mixte a été effectuée : quantitative,glycémies, hypoglycémies, durée de séjour et qualitative, évolution de la réflexionautour de l'hyperglycémie.Résultats : Nov. 2009-2010, dans le Service de Médecine du CHUV, nous avonsdispensé 3 sessions de formation (15 cours), suivies d'une période de coaching,pour 78 internes. Évaluation quantitative : 85 patients (56,4 % H), âge moyen72,7 ± 9,6 ans, glycémies à J3 dans la cible (4-8,5 mmol/l) 44,6 %, glycémiemoyenne 8,5 ± 1,8 mmol/l, hypoglycémies 0,9 %, durée moyenne de séjour9,7 ± 5,4 J. Évaluation qualitative : choix du schéma thérapeutique pertinentdans la majorité des cas, environ 90 % des internes ont intégré les éléments depondération de l'insulinothérapie, estiment que cette formation a eu un impactpositif sur leur gestion, sont plus confiants dans leurs capacités et ont unmeilleur sentiment d'auto-efficacité. Les modalités pédagogiques adoptées ontfavorisé le transfert des compétences et le niveau de satisfaction globale atteint90 %.Conclusion : Le développement d'un programme de formation des soignants,basé sur l'approche réflexive et participative, permet une amélioration importantede la gestion de l'hyperglycémie. Notre projet s'inscrit dans une démarcheglobale visant à doter les bénéficiaires d'une vision systémique du diabète.

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In the last 15 years, the therapeutical options for the treatment of chronic inflammatory diseases in rheumatology have increased a lot. Nevertheless, some patients do not respond or respond partially to the current therapies--including to the biologics therapy. Tofacitinib (Xeljanz) is now on the Swiss market. It inhibits the JAK pathway. Tofacitinib--as monotherapy or with methotrexate--improves the control of rheumatoid arthritis (RA). In a comparative study, tofacitinib was as effective as adalimumab. Further, tofacitinib reduced structural damages in RA and is considered as an alternative, in case of non-response, to anti-TNF and probably to other biologics therapy. The side effects are upper respiratory tract and opportunist infections and tuberculosis. Blood count, lipids, kidney function, liver tests, CK and blood pressure have to be monitored.

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Acute exacerbation of COPD is one of the most common causes of hospital admission in patients affected with this disease. In most cases, consideration of differential diagnoses and assessment of important comorbidities will allow to make the decision whether or not the patient needs to be hospitalized. A decision to hospitalize will be based on specific symptoms and signs, as well on the patient's history. Contrary to bronchial asthma, a systematic action plan strategy is lacking for COPD. However, a disease management plan involving all the health care providers may have the potential to improve the patient's well being and to decrease costs related to these exacerbations.

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In the absence of works which would significantly change the perspective on the management of diabetes in the elapsed year, this article proposes a reflection on the integration of the evolving knowledge over the past decade into clinical practice. The major preventive impact of an approach targeting all the cardiovascular risk factors in diabetic patients will remain as the main lesson of this decade. The therapeutic goals need to be tailored to the individual patient's situation based on the evaluation of the benefit: inconvenience-ratio of the treatments. The process of their choice has to include the quest for a shared vision with the patient who is in charge of diabetes management in daily life.

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Crystallization of anatectic melts in high-temperature metamorphic terrains releases volatile-rich magmas that can be transported into adjacent lithologies. This study addresses the variations in the oxygen, boron and hydrogen isotopic composition of aplite-pegmatite dikes that formed during the crystallization of anatectic melts in regional high-temperature metamorphism on the island of Naxos, Greece, and propagated upward into the overlying sequences of metamorphic schist. The transport distance of these dikes was increased through a significant horizontal component of travel that was imposed by contemporaneous low-angle extensional shearing. Laser fluorination oxygen isotope analyses of quartz, tourmaline, garnet, and biotite mineral separates from the aplite-pegmatite dikes show a progressive rise in delta(18)O values with increasing distance from the core. Oxygen isotope fractionations among quartz, tourmaline, and garnet show temperature variations from > 700degreesC down to similar to400degreesC. This range is considered to reflect isotopic fractionation beginning with crystallization at high temperatures in water-undersaturated conditions and then evolving through lower temperature crystallization and retrograde sub-solidus exchange. Two processes are examined for the cause of the progressive increase in delta(18)O values: (1) heterogeneous delta(18)O sources and (2) fluid-rock exchange between the aplite/pegmatite magmas and their host rock. Although the former process cannot be ruled out, there is as yet no evidence in the exposed sequences on Naxos for the presence of a suitable high delta(18)O magma source. In contrast, a tendency for the delta(18)O of quartz in the aplite/pegmatite dikes to approach that of the quartz in the metamorphic rock suggests that fluid-rock exchange with the host rock may potentially be an important process. Advection of fluid into the magma is examined based on Darcian fluid flow into an initially water-undersaturated buoyantly propagating aplitic dike magma. It is shown that such advective flow could only account for part of the O-18-enrichment, unless it were amplified by repeated injection of magma pulses, fluid recycling, and deformation-assisted post-crystallization exchange. The mechanism is, however, adequate to account for hydrogen isotope equilibration between dike and host rock. In contrast, variations in the delta(11)B values of tourmalines suggest that B-11/B-10 fractionation during crystallization and/or magma degassing was the major control of boron geochemistry rather than fluid-rock interaction and that the boron isotopic system was decoupled from that of oxygen. Copyright (C) 2003 Elsevier Ltd.