Search results for "Hg"
showing 10 items of 262 documents
Synthèse de nouveaux agents bimodaux hydrosolubles pour l'IRM, l'imagerie nucléaire, l'imagerie biphotonique et la génération de second harmonique
2015
The goal of my PhD studies was to synthesize new compounds for possible medical imaging applications. The first part of my thesis focused on the synthesis of heteroleptic ligands to achieve the chelation of two different metals aimed at addressing two types of medical imaging. We first synthesized porphyrins, which are well-known for the chelation of numerous transition metals. We focused on copper, whose copper-64 isotope is a β+ emitter usable in Positron Emission Tomography (PET). These porphyrins have been coupled with a DOTA derivative. This molecule, metallated with gadolinium, is well-known in Magnetic Resonance Imaging (MRI). Our compounds display encouraging relaxivities for MRI ap…
Ultraviolet quasi-phase-matched second harmonic generation in surface periodically poled lithium niobate optical waveguides
2007
The compatibility of low concentration (alpha-phase) proton exchange channel waveguides with electric field surface periodic poling of congruent lithium niobate (SPPLN) crystals has been experimentally demonstrated. With such waveguides, we obtained ultraviolet second harmonic generation (SHG) by first order quasi-phase-matching (QPM), a result made possible by the fabrication, on Z-cut LN crystals, of periodic structures with a pitch down to 750 nm. Nonlinear copropagating QPM-SHG measurements have been carried out on such structures. The pump source was a Ti:sapphire laser with a tunability range of 700-980 nm and a 40 GHz linewidth. We have measured UV continuous wave light at 390 nm by …
A new marketing mix model to rescue the hospitality industry: Evidence from Egypt after the Arab Spring
2017
After January 25th 2011 Egypt witnessed political, economic and social instability leading to drastic consequences in the hospitality and tourism industry. Thus unstable situation reflected on the deteriorated occupancy percentages that led to declined profit margins, higher employee layoffs and degraded quality of product and services. The objectives of this research is to examine how the Egyptian hospitality properties manage this dilemma through their marketing practices, and to propose a new marketing mix model that adds new layers of depth to the traditional marketing mix model. A methodological framework was designed to help in the assessment process of management practices pertaining…
On the signaling effect of reward-based crowdfunding: (When) do later stage venture capitalists rely more on the crowd than their peers?
2021
Abstract Venture capitalists (VCs) make only a small number of investments and are more likely to invest in ventures where other VCs have invested previously. As such, valuable opportunities may be forgone if they are not funded by VCs in the first place. We demonstrate how crowdfunding (CF) can remedy this concern. Using a sample of new technology-based ventures, we reveal that ventures initially funded through reward-based CF can be even more likely than those initially backed by VCs in attracting follow-up funds from VCs. This happens when ventures originally funded via reward-based CF complement the certification they derive from CF with patents and a founding team with a track record o…
The economic impact of audit failures
2022
This paper examines the economic consequences associated with an audit failure in the field of statutory auditing services, by analyzing changes in the audit firm’s market share around the time of the investigation process undertaken by the Spanish Public Oversight Board. We explore the variations in audit market share by applying the difference in differences method to a treatment group of 70 sanctioned audit firms and a matched control group of 70 non-sanctioned audit firms. The period of analysis covers the years from 1999 to 2015. Our results show that the sanctioned audit firms suffered a significant decrease in their relative number of clients. Moreover, this measure of market share d…
Second Harmonic Generation via Random Quasi-phase Matching in a Periodically Poled Lithium Tantalate Waveguide
2011
We observe second harmonic generation via random quasi phase matching in a 1.5μm periodically poled lithium tantalate. The presence of a slab waveguide allows the comparison between bulk and guided wave configurations.
The Sehgal’s Fixed Point Result in the Framework of ρ-Space
2022
In this paper, we prove a fixed point theorem of Sehgal type (see Sehgal, V.M., Proc Amer Math Soc 23: 631–634, 1969) in a more general setting of ρ-space (see Secelean, N.A. and Wardowski, D., Results Math, 72: 919–935, 2017). In this way, we can find, as particular cases, some results of Sehgal type in metric, b-metric and rectangular b-metric spaces.
Acquisition of competencies with serious games in the accounting field: an empirical analysis
2018
El actual sistema de educación superior se basa en un aprendizaje activo por parte del estudiante enfocado al desarrollo de competencias genéricas y específicas. En este contexto muchos autores defienden el uso de simulaciones que favorezcan dicho aprendizaje y, los denominados «juegos serios» (serious games [SG]) se adaptan a este reto. Sin embargo, el empuje que cabría esperar por el desarrollo de las nuevas tecnologías y de la llegada de los denominados «nativos digitales» a las aulas no es coherente ni con su grado de implantación ni con la escasa investigación desarrollada sobre la efectividad de su uso. Los objetivos de este estudio son describir una experiencia docente de implantació…
Chromatin epigenetics and nuclear lamina keep the nucleus in shape: Examples from natural and accelerated aging.
2022
As the repository of genetic information, the cell nucleus must protect DNA integrity from mechanical stresses. The nuclear lamina, which resides within the nuclear envelope (NE), is made up of lamins, intermediate filaments bound to DNA. The nuclear lamina provides the nucleus with the ability to deal with inward as well as outward mechanical stimuli. Chromatin, in turn, through its degrees of compaction, shares this role with the nuclear lamina, thus, ensuring the plasticity of the nucleus. Perturbation of chromatin condensation or the nuclear lamina has been linked to a plethora of biological conditions, that range from cancer and genetic diseases (laminopathies) to aging, both natural a…
Life Cycle Energy Consumption and Air Emissions Comparison of Alternative and Conventional Bus Fleets in Vietnam
2022
The study (a) assesses the life cycle energy consumption and air emissions impacts of battery electric buses (e-buses) and conventional buses operated in Vietnam, and (b) compares them with those of hydrogen buses. The results indicate that e-buses and hydrogen buses are preferred options compared to conventional buses in terms of energy consumption, GHG emissions and other air quality impacts over their whole life cycle. Life cycle energy consumption of diesel buses is triple that of e-buses, and is significantly higher than that of hydrogen buses. Replacing conventional buses with e-buses can reduce energy consumption by 50%. For GHG emissions and air quality impacts, the adoption of elec…