999 resultados para Transport de sediments


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The membrane-bound serine protease CAP2/Tmprss4 has been previously identified in vitro as a positive regulator of the epithelial sodium channel (ENaC). To study its in vivo implication in ENaC-mediated sodium absorption, we generated a knockout mouse model for CAP2/Tmprss4. Mice deficient in CAP2/Tmprss4 were viable, fertile, and did not show any obvious histological abnormalities. Unexpectedly, when challenged with sodium-deficient diet, these mice did not develop any impairment in renal sodium handling as evidenced by normal plasma and urinary sodium and potassium electrolytes, as well as normal aldosterone levels. Despite minor alterations in ENaC mRNA expression, we found no evidence for altered proteolytic cleavage of ENaC subunits. In consequence, ENaC activity, as monitored by the amiloride-sensitive rectal potential difference (ΔPD), was not altered even under dietary sodium restriction. In summary, ENaC-mediated sodium balance is not affected by lack of CAP2/Tmprss4 expression and thus, does not seem to directly control ENaC expression and activity in vivo.

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The electrical and electroluminescence (EL) properties at room and high temperatures of oxide/ nitride/oxide (ONO)-based light emitting capacitors are studied. The ONO multidielectric layer is enriched with silicon by means of ion implantation. The exceeding silicon distribution follows a Gaussian profile with a maximum of 19%, centered close to the lower oxide/nitride interface. The electrical measurements performed at room and high temperatures allowed to unambiguously identify variable range hopping (VRH) as the dominant electrical conduction mechanism at low voltages, whereas at moderate and high voltages, a hybrid conduction formed by means of variable range hopping and space charge-limited current enhanced by Poole-Frenkel effect predominates. The EL spectra at different temperatures are also recorded, and the correlation between charge transport mechanisms and EL properties is discussed.

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Tämän tutkielman tarkoituksena on selvittää suomalaisen kartonkikuljetuspakkausfirman, Eltete TPM Oy:n, tulevaisuudennäkymät selvittämällä voiko puisen kuljetuspakkausmateriaalin korvata kartonkisilla materiaaleilla. Kyseinen tutkimus suoritetaan selvittämällä toimialanmuutokseen vaikuttavia tekijöitä kuten ostokäyttäytymistä, innovaation ominaisuuksia, säädöksiä, kilpailuympäristöä sekä lopuksi tutkimalla mitä kuljetuspakkauksien asiakkaat haluavat ja tarvitsevat. Kyseisen tutkimuksen kohdeasiakkaiksi valittiin suurimmat kodinkoneyritykset Euroopassa ja tutkimusmenetelmäksi postikysely. Suoritetun markkinointitutkimuksen tulokset kodinkoneyritysten pakkausratkaisuista sekä kilpailija-analyysi osoittivat, että todella on olemassa kasvava kysyntä kierrätettäville kartonkisille kuljetuspakkausratkaisuille, kuten Eltete TPS - Framepack solution on, sekä että Eltete TPM Oy:llä on voimavaroja tulevaisuudessa nousta markkinajohtajaksi muuttuvalla kuljetuspakkaussektorilla.

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Hydrogenated nanocrystalline silicon (nc-Si:H) obtained by hot-wire chemical vapour deposition (HWCVD) at low substrate temperature (150 °C) has been incorporated as the active layer in bottom-gate thin-film transistors (TFTs). These devices were electrically characterised by measuring in vacuum the output and transfer characteristics for different temperatures. The field-effect mobility showed a thermally activated behaviour which could be attributed to carrier trapping at the band tails, as in hydrogenated amorphous silicon (a-Si:H), and potential barriers for the electronic transport. Trapped charge at the interfaces of the columns, which are typical in nc-Si:H, would account for these barriers. By using the Levinson technique, the quality of the material at the column boundaries could be studied. Finally, these results were interpreted according to the particular microstructure of nc-Si:H.

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The high alpine valleys in the Southem Pyrenees are characterised by a many small lakes and ponds. They occur above 2000 m and are said to have been formed by glacial erosion. The sediments in these basins should, therefore, contain s t p tigraphic information since deglaciation, at least. An interesting and may be one of the most important of these basins is Lake Llauset in the Alta Ribagorca. The Llauset basin has recently been developped for hydsopower production. In conection with the construction of the retaining wall at the 'Riegel' the sedimentary filling of the lake basin could be investigated, and the first sedimentological and stratigraphicalresults are presented.

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The origin of Spanish regional economic divergence can be traced back at least until the seventeenth century, although its full definition took place during industrialisation. Historians have often included uneven regional infrastructure endowments among the factors that explain divergence among Spanish regions, although no systematic analysis of the spatial distribution of Spanish infrastructure and its determinants has been carried out so far. This paper aims at filling that gap, by offering a description of the regional distribution of the main Spanish transport infrastructure between the middle of the nineteenth century and the Civil War. In addition, it estimates a panel data model to search into the main reasons that explain the differences among the Spanish regional endowments of railways and roads during that period. The outcomes of that analysis indicate that both institutional factors and the physical characteristics of each area had a strong influence on the distribution of transport infrastructure among the Spanish regions.

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El gran impacte que El Niño - Oscil·lació del Sud (ENSO) té en la nostra societat industrialitzada ha esperonat la comunitat científica d'arreu a entendre quins són els mecanismes físics que el controlen, així com clarificar quina ha estat la seva història. El registre sedimentari de sensors naturals, com els llacs o la mar, ha permès reconstruir la història de l'ENSO. En aquest article, els autors donen una visió sintètica de la història d'aquest fenomen climàtic al llarg dels darrers quatre milions d'anys.

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El gran impacte que El Niño - Oscil·lació del Sud (ENSO) té en la nostra societat industrialitzada ha esperonat la comunitat científica d'arreu a entendre quins són els mecanismes físics que el controlen, així com clarificar quina ha estat la seva història. El registre sedimentari de sensors naturals, com els llacs o la mar, ha permès reconstruir la història de l'ENSO. En aquest article, els autors donen una visió sintètica de la història d'aquest fenomen climàtic al llarg dels darrers quatre milions d'anys.

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Spain’s transport infrastructure policy has become a paradigmatic case of oversupply and of mismatch with demand. The massive expansion of the country’s transport infrastructure over the last decade has not been a response to demand bottlenecks or previously identified needs. For this reason, the intensity of use today on all interurban modes of transport in Spain falls well below that of other EU countries. This paper analyzes the institutional and regulatory factors that have permitted this policy, allowing us to draw lessons from the Spanish case that should help other countries avoid the pitfalls and shortcomings of Spanish policy.

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Spain’s transport infrastructure policy has become a paradigmatic case of oversupply and of mismatch with demand. The massive expansion of the country’s transport infrastructure over the last decade has not been a response to demand bottlenecks or previously identified needs. For this reason, the intensity of use today on all interurban modes of transport in Spain falls well below that of other EU countries. This paper analyzes the institutional and regulatory factors that have permitted this policy, allowing us to draw lessons from the Spanish case that should help other countries avoid the pitfalls and shortcomings of Spanish policy.

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Spain’s transport infrastructure policy has become a paradigmatic case of oversupply and of mismatch with demand. The massive expansion of the country’s transport infrastructure over the last decade has not been a response to demand bottlenecks or previously identified needs. For this reason, the intensity of use today on all interurban modes of transport in Spain falls well below that of other EU countries. This paper analyzes the institutional and regulatory factors that have permitted this policy, allowing us to draw lessons from the Spanish case that should help other countries avoid the pitfalls and shortcomings of Spanish policy. Based on our analysis, we also discuss policy remedies and suggest reforms in different regulatory areas, which could help improve the performance of Spain’s infrastructure policy.

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The small intestine is a dynamic and complex organ that is characterized by constant epithelium turnover and crosstalk among various cell types and the microbiota. Lymphatic capillaries of the small intestine, called lacteals, play key roles in dietary fat absorption and the gut immune response; however, little is known about the molecular regulation of lacteal function. Here, we performed a high-resolution analysis of the small intestinal stroma and determined that lacteals reside in a permanent regenerative, proliferative state that is distinct from embryonic lymphangiogenesis or quiescent lymphatic vessels observed in other tissues. We further demonstrated that this continuous regeneration process is mediated by Notch signaling and that the expression of the Notch ligand delta-like 4 (DLL4) in lacteals requires activation of VEGFR3 and VEGFR2. Moreover, genetic inactivation of Dll4 in lymphatic endothelial cells led to lacteal regression and impaired dietary fat uptake. We propose that such a slow lymphatic regeneration mode is necessary to match a unique need of intestinal lymphatic vessels for both continuous maintenance, due to the constant exposure to dietary fat and mechanical strain, and efficient uptake of fat and immune cells. Our work reveals how lymphatic vessel responses are shaped by tissue specialization and uncover a role for continuous DLL4 signaling in the function of adult lymphatic vasculature.