12,746 research outputs found
POSTULA A LA BECA JUAN MONTÚFAR: MÁS ALLÁ DE DOMINAR
No full textLa Beca Juan García Montúfar promueve oportunidades para que jóvenes talentosos puedan dominar las normas mineras y enfrentar los desafíos de esta industria estratégica. Estudia Derecho para la Actividad Minera La minería es una de las industrias más importantes para la economía global y demanda profesionales especializados en derecho minero. Esta beca brinda acceso a una formación completa
Efficacy of hemostatic powders in upper gastrointestinal bleeding: A systematic review and meta-analysis
No full textMicroRNAs fingerprint of bicuspid aortic valve
No full textAortic valve tissue is largely exposed to high blood flow. Cells belonging to aortic valve tissues are able to detect and respond to flow conditions changes. Bicuspid aortic valve (BAV) presents altered morphology, with only two abnormal cusps instead of three. This results in an alteration of blood flow dynamics on valve cusps and aortic wall, which may, in turn, increase the risk to develop aortic stenosis and/or regurgitation, endocarditis, aortopathy and/or aortic dissection. MicroRNAs (miRNAs) are short RNA strands regulating gene expression mainly through the inhibition of their target mRNAs. They are largely involved in cardiovascular pathophysiology and heart disease. More recently, it has been observed that the expression of specific miRNAs can be modulated in response to changes in hemodynamic conditions. Using a bioinformatic approach, this article analyses available scientific evidence about the differential expression of miRNAs in the bicuspid aortic valve, with a focus on the differential modulation compared to the calcific-degenerative tricuspid aortic valve
Conversion of synthesis gas to isobutylene over precipitated zirconia based catalysts
No full textVita.Recent amendments to the Clean Air Act have renewed interest in synthesizing isobutylene from coal derived synthesis gas for use in producing methyl tertiary-butyl ether. Previous work on isosynthesis was performed at extreme conditions or at very low conversions. No rate equation to predict carbon monoxide conversion or methods to predict product distribution existed. In this study zirconia catalysts were synthesized by a precipitation, a hydrothermal, and a calcination method. The effects of sodium, titanium, manganese, cerium, and thorium additives were initially investigated. Catalysts prepared by the precipitation method were most active followed by calcination and hydrothermal preparation. The hydrothermal catalysts were more selective to the iso-C4's. Of the initial catalysts, a 796 (wt) cerium zirconia was found to be most active. When hydrogen sulfide was included in the feed a dramatic shift in product selectivity occurred with no loss in catalytic activity. The C2+C3 fraction was reduced by about half while the Cs fraction was increased by a factor of two an a half. This increase was realized in the formation of 3-methyl-l-butene, the second least thermodynamically favored C5 hydrocarbon, which showed an eighteenfold increase. Presulfiding the catalyst resulted in a more pronounced shift to the C5's with a slight reduction in activity. The theory that oxygen vacancies are the catalytic site for isosynthesis was tested by doping zirconia catalysts with various levels of +1, +2, +3, and +5 oxides. The dopants studied included lithium, magnesium, aluminum, dysprosium, and tantalum. Additionally, a zirconia catalyst containing yttrium, barium, and copper in a 1:2:3 ratio was prepared. Catalyst testing showed that oxygen vacancies are required for an active catalyst and that oxygen vacancies also play a vital role in the selectivity of isosynthesis catalysts. Results indicated that the most active single component doped catalyst should introduce the most oxygen vacancies per cation incorporated into the lattice and have an ionic radius close to that of zirconium. Carbon monoxide conversion was successfully modeled with a rate equation dependent on the partial pressures of CO, H2, and C02. The product distribution was modeled by a simple extension of the rate equation. Reproduce
Professional Dimension of IT Specialists' Social Role
No full textThis chapter gives the opportunity to describe and analyze how IT specialists construct their professional reality and how they perform their roles. Nowadays companies (or top management) influence its employees in multiple aspects. Thus, professional relations should be investigated in the terms of mutual interactions within the organization, which is the main topic of the chapter. Often, top management tries to conclusively define (consciously or unconsciously) what the organization is. It means that workers of lower levels in such companies are manipulated by their higher-level colleagues. Sometimes this influence, albeit both hierarchical and controlling, leaves some space for the development of more equal bonds. In other organizations, manipulation is not a part of the standard work climate. The relations between the employees are, in such organizations, based on rituals and direct communication. The most important detail of this construction is to take care of every interaction between all organization’s actors. In this chapter, I intend to describe work relations and other aspects of everyday work life of IT professionals. Empirical material is derived from the field research conducted during 2002-2004 in two stages with different intensity of data gathering. The first stage of the research concerned a software company creating customized business software “to meet the requirements of clients.” The second stage was based on interviews with IT professionals from different organizations including software companies, international corporations, and also IT departments within companies operating in different business branches. Complete analysis of gathered material is presented in a doctoral thesis (Postula, 2007). Therefore, in case of some discontinuity of considerations in this chapter I would refer to the full text.</jats:p
Licencia concedida por el Sagrado Conserva-torio de Roma a Fr. Mateo Ximenez como Postula-dor de la Causa del Venerable Aparicio. (Roma, 14, 15 noviembre 1788).
No full textLicencia concedida por el Sagrado Conserva-torio de Roma a Fr. Mateo Ximenez como Postula-dor de la Causa del Venerable Aparicio. (Roma, 14, 15 noviembre 1788)
Optimal duration and combination of antiplatelet therapies following percutaneous coronary intervention: a meta-analysis
No full textInvestigations into a semi-blind channel estimation technique for 2x2 MIMO system
No full textThe paper reports on investigations into semi-blind channel estimation for a 2×2 Multiple Input Multiple Output (MIMO) system employing the Alamouti coding scheme. The proposed technique is based on an iterative version of Maximum Likelihood technique and uses a suitable weighting of channel matrices in the current and last iterations. In the presented investigations, it is assumed that the channel properties vary gradually, such as in slow and block fading. It is shown that the performance of the proposed semi-blind channel estimation depends on the weighting factor and the rate of fading
Specialised processor for channel allocation in a cellular mobile network
No full textThe capacity of the current cellular mobile telephone networks has the potential to be doubled by adapting transmission power control strategies into the control stations. We propose a new channel assignment method, which combines power control and distributed balancing algorithm. In contrast with centralised control methods, the proposed algorithm has much less communication overhead and requires simpler computations to be executed in parallel on different cells. Conventional processors can be used to perform these calculations reside within the algorithm. However, we propose using simple specialised hardware, which outperforms conventional processors in mathematical intensive algorithms and large number of I/O operations. The dedicated hardware allows all channels within the cell to be balanced at the same time, resulting in optimal channel utilisation
Flow-Responsive Noncoding RNAs in the Vascular System: Basic Mechanisms for the Clinician
No full textThe vascular system is largely exposed to the effect of changing flow conditions. Vascular cells can sense flow and its changes. Flow sensing is of pivotal importance for vascular remodeling. In fact, it influences the development and progression of atherosclerosis, controls its location and has a major influx on the development of local complications. Despite its importance, the research community has traditionally paid scarce attention to studying the association between different flow conditions and vascular biology. More recently, a growing body of evidence has been accumulating, revealing that ncRNAs play a key role in the modulation of several biological processes linking flow-sensing to vascular pathophysiology. This review summarizes the most relevant evidence on ncRNAs that are directly or indirectly responsive to flow conditions to the benefit of the clinician, with a focus on the underpinning mechanisms and their potential application as disease biomarkers
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