La formación y ejecución del contrato electrónico: aproximación a una realidad negocial emergente

Este trabajo ofrece unas consideraciones generales acerca de lo que ha dado en llamarse contrato electrónico y, más en concreto, acerca de su formación y ejecución. Con tal propósito, tras concretarse el marco normativo del contrato electrónico, sometido recientemente a algunas modificaciones significativas, la atención se centra en dos extremos principales: 1.º) la disciplina legal aplicable a la perfección, ejecución y prueba del contrato electrónico, con referencia al régimen jurídico relativo a la incorporación de condiciones generales; y 2.º) los aspectos más sobresalientes de la normativa reguladora del contrato electrónico en cuanto modalidad singular de contrato a distancia (desestimiento negocial, etc.)

Atmospheric circulation influence on the interannual variability of snow pack in the Spanish Pyrenees during the second half of the 20th century

12 páginas, 5 figuras, 6 tablas.Large areas in the Spanish Pyrenees are covered by snow between December and April, especially above 1650 m a.s.l., the location of the cold season 0°C isotherm. However, a significant negative trend in Pyrenean snow pack was detected during the second half of the 20th century. This paper analyses the interannual evolution of snow accumulation in these mountains in relation to the variability of atmospheric circulation. The study considers two spatial scales, from weather types over the Iberian Peninsula to hemispheric atmospheric patterns. The results show strong relationships between the annual occurrence of several weather types and spring snow accumulation. Changes in the frequency of several weather types are explained by the evolution of large scale hemispheric circulation patterns, especially the North Atlantic Oscillation (NAO). Thus, the positive trend observed in the NAO index leads to a decrease in the occurrence of types that favour snow accumulation and an increase in unfavourable conditions for snow pack during the second half of the 20th century.This study was supported by the following research projects: PIRIHEROS, REN 2003- 08678/HID, CGL2005-04508/BOS and CANOA, CGL 2004-04919-c02-01, all funded by the CICYT, Spanish Ministry of Science and Technology. The research of the authors was supported by postdoctoral fellowships from the Spanish Ministry of Education, Culture and Sports, Spain.Peer reviewe

Influence of Ceramic Recycled Aggregates on the Properties of Prestressed Precast Concrete Elements

This work presents the results of an experimental study performed on the mechanical behavior of concrete manufactured with ceramic recycled aggregates (CRA), from precast ventilation ducts, that once made have been rejected by defective. The ultimate objective is to use these wastes to manufacture prestressed concrete joists used in building floors. The coarse fraction and the fine fraction have been considered. The work has been carried out in three phases: characterization of the material, characterization of concrete with CRA and manufacturing and testing of prestressed joists. With the results obtained it is determined the influence of the ceramic recycled aggregate on the properties analyzed. There are not enough studies about prestressed elements that include the replacement of the aggregate in the fine fraction. In view of the results obtained could both of fine and coarse fraction can be used in these applications

Elite coaches’ approach to quantifying technical actions and relative participation in volleyball players’ performance

This study sought to identify elite coaches’ perception of the importance of technical actions and the consideration of relative participation to measure individual volleyball players’ performance. An instrument was elaborated to gather the opinions of elite coaches on the importance of technical actions reported by the data volley (excluding setting), as well as considering relative participation. Twenty elite coaches with at least three years of experience in national teams or top leagues participated in the study. Variables considered in the study were analysed using descriptive statistics and reliability was measured with Cronbach’s α and McDonald’s Omega coefficients (> .70). The results assessed the importance of scoring actions, which received values of (1 point). All errors (terminal and continuity) were scored with (−1). Non-scoring actions were given values [.00, .80], except for poor attack (−.35), poor serve (−.60), free freeball (−.60) and reception free (−.50). Relative participation was considered according to the percentage of points and/or contacts played by each athlete. We concluded that for the player’s points and/or contacts, priority is given to actions that win points directly or are excellent, followed by those that contribute to building comfortable attacks, while penalising errors

El paleógeno del sector suroccidental de la Cuenca del Duero: nueva división estratigráfica y controles sobre su sedimentación

Como resultado de un detallado trabajo cartográfico, estratigráfico y sedimentológico, se propone la división del Paleógeno del sector suroccidental de la Cuenca del Duero en cuatro U.T.S. limitadas por discordancias. Estas D.T.S., que abarcan desde el tránsito Cretácico superior-Paleoceno hasta el Oligoceno, incluyen distintas unidades litoestratigráficas que sonreordenadas, modificando la sucesión estratigrática propuesta por los autores anteriores. Se asigna a la U.T.S. Me una edad Cretácico superior-Paleoceno. Se individualiza el Eoceno inferior (U.T.S. PI) en la zona de Salamanca. Se reinterpreta la relación existente entre los materiales del Eoceno mediosuperior y los del Eoceno superior-Oligoceno considerándolos en tránsito por lo que se asignan a una única U.T.S. (UT.S. P2, Eoceno medio Oligoceno inferior). Se incluyen en la U.T.S. P3 (Oligoceno superior) los sedimentos arcósicos anterionnente considerados como Vatlesienses. Así mismo, se considera que gran parte de los materiales asignados al mioceno inferior son sedimentos paleógenos afectados por un proceso de alteración de edad Miocena, lo que implica una variación en la extensión y límites de la cuenca neógena en su extremo SO. Se analiza la evolución de las distintas U.T.S. deduciendo un carácter tectónico para las megasecuencias propuestas relacionado con el progresivo levantamiento de las áreas fuente. El clima muestra un tránsito desde condiciones tropicales sin estaciones contrastadas (U,T.S. MC) hasta un clima mediterráneo árido (U.T.S. P3) con una estación seca muy marcada y una corta estación húmeda caracterizada por violentas avenidas. [ABSTRACT] A Paleogene four-fold stratigraphical division is proposed here as result fram the detailed studies carried out during the elaboration of 22 sheets of the Geological Map of Spain (E. 1 :50.000). This units (T.S.U.) are limited by regional discordances and they have a Upper Cretaceous to Oligocene ages. The previous stratigraphical schemes are rearranged due to the different stratigraphical relations observed between the lithostratigraphical units proposed by other workers (Jiménez, 1970; Corrochano, 1977; Alonso, 1981...). An Upper Cretaceous-Paleocene age is assumed to T.S.U. MC which is mainly composed by siliciclastic sediments strongly silicified forming a FU megasequence. It is intcrpretated as braided streams that flowed downslope filling paleovalleys erodcd onto Paleozoic materiaIs. Mineralogical features point to a tropical climate. Lower Eocene (T.S.U. P I ) is identified in the Salamanca area, where ir was considered as lacking. It is composed by arkosic sediments forming a CU megasequence. Fossil faunas of this T.S.U. record a subtropical clima te. It is observed a transition from high sinuosity streams to braided ones. T.S.U. P2 (Middle Eocene-Lower Oligocene) is composed of two lithostratigraphical units previously considered as bounded by a discordance (Alonso, 1981).It has a subarkosic to lithic nature and forms a CU megasequence. This unit records a subtropical climate with short arid periods and is interpretated as braided streams showing an increasing stability and enviromental energy to the topo T.S. U. P3 (Upper Oligocene) is composed by arkosic sediments previously considered of Vallesian (Middle to Upper Miocene) age. They form a CU megasequence that records braided streams prograding basinwardfrom higher arcas. Palinological associations and pedological features indicate an arid mediterranean climate with long arid periods and a short rainy season with strong floods. We consider that most of Lower Miocene sediments are of Paleogene age. They are afected by a widespread alteration profile developed along Lower Miocene that masked its more significative features. Sedimentological analysis of T.S.U. shows that its megasequentiality is related to the rates of tectonical uplift of source arcas whereas a distensive regime developed in the sedimentation basin

Appearance of pyrophyllite as replacements of spiriferids (Brachiopoda) Shells of the devonian in the Central-Iberian zone (Hesperic Massif, Spain).

[Abstract] Amacroscopic pyrophyllite bearing mineralization related to shells ofspiriferids has beeen found in the Herrera Formation (southern Central-Iberian Zone, Hesperic Massif, Spain). The observed mineral asociation is pyrophyllite + nacrite + quartz + calcite + anhydrite, and it is interpreted as resulting from the substitution ofinitial carbonatic shell by a Si, Al, S rich hydrothermal solutio

Hepatozoonosis canina

Se diagnosticó hepatozoonosis en cuatro perras de raza beagle que habían sufrido una infestación masiva por garrapatas. Se describe el cuadro clínico, protocolo laboratorial, diagnóstico diferencial, tratamiento y evolución. Tras eliminar la presencia de otros procesos patológicos, concluimos que Hepatozoon canis produce una reacción leucoeritroblástica, que remite con el tratamiento.The study diagnosed canine hepatozoonosis in four Beagles, that become infested with ticks. It describes the clinical signs, laboratory protocol, diferential diagnosis, treatment and evolution. After eliminate the presence of other pathology, we conclude what Heparozoon canis causes a leucoeritroblastic reaction, that remit with treatment

Dynamic Kinetic Resolution of Hetero biaryl Ketones by Zinc- Catalyzed Asymmetr ic Hydrosil ylation

Adiastereo- and highly enantioselective dynamic kinetic resolution (DKR) of configurationally labile hetero- biaryl ketones is described. The DKR proceeds by zinc- catalyze dhydrosilylation of the carbonyl group ,thus leading to secondary alcohols bearing axial and central chirality .The strategy relies on the labilization of the stereogenic axis that takes place thanks to aLewis acid–base interaction between anitrogen atom in the heterocycle and the ketone carbonyl group .The synthetic utility of the methodology is demonstrated through stereospecific transformations into either N,N-ligands or appealing axially chiral, bifunctional thiourea organocata- lysts.Ministerio de Ciencia e Innovación (Grants CTQ2016-76908-C2-1-P, CTQ2016-76908-C2-2-P, contract RYC-2013-12585)European FEDER FundsJunta de Andalucía (Grant 2012/FQM 10787)European Union - Marie Skłodowska-Curie (COFUND—Grant Agreement n 8 8 291780

Endothelial Aging Associated with Oxidative Stress Can Be Modulated by a Healthy Mediterranean Diet

Aging is a condition which favors the development of atherosclerosis, which has been associated with a breakdown in repair processes that occurs in response to cell damage. The dysregulation of the biological systems associated with aging are produced partly through damage which accumulates over time. One major source of this injury is oxidative stress, which can impair biological structures and the mechanisms by which they are repaired. These mechanisms are based on the pathogenesis of endothelial dysfunction, which in turn is associated with cardiovascular disease, carcinogenesis and aging. The dependent dysfunction of aging has been correlated with a reduction in the number and/or functional activity of endothelial progenitor cells, which could hinder the repair and regeneration of the endothelium. In addition, aging, inflammation and oxidative stress are endogenous factors that cause telomere shortening, which is dependent on oxidative cell damage. Moreover, telomere length correlates with lifestyle and the consumption of a healthy diet. Thus, diseases associated with aging and age may be caused by the long-term effects of oxidative damage, which are modified by genetic and environmental factors. Considering that diet is a very important source of antioxidants, in this review we will analyze the relationship between oxidative stress, aging, and the mechanisms which may be involved in a higher survival rate and a lower incidence of the diseases associated with aging in populations which follow a healthy diet