461 research outputs found
Incidence of a "social VAT" reform: A French scenario
This paper studies the fiscal incidence of a fiscal reform consisting of a reduction in employers' social insurance contributions financed by a tax based on the value added. In a closed economy with two sectors calibrated thanks to the French National Accounts, a social VAT leads to a rise in labor incomes which is usually higher than the rise of capital incomes. In case of perfect intersector mobility of production factors, a reduction in 1 percentage point of the social contributions leads to a rise in net labor incomes which is 0:51 to 0:66 percentage point higher than the rise of the interest rate. For a low intersector mobility the gains of workers, even though unequally distributed, remain higher than that of capitalists. In an open economy when the international capital mobility is sufficiently high, workers are more inclined to suffer from the reform
One-step microwave synthesis of palladium-carbon nanotubes hybrids with improved catalytic performance
7 páginas, 7 figuras, 3 tablas.-- El pdf del artículo es la versión pre-print.A fast and easy one-step linker-free approach for the synthesis of palladium nanoparticle/multiwall carbon nanotube (Pd-NP/MWCNT)hybrid materials is described using microwave irradiation for the effective decomposition of Pd2dba3 complex in the presence of MWCNTs. High loadings of Pd nanoparticles (up to 40 wt.%) having sizes between 3 and 5 nm are deposited on the surface of MWCNTs within a time of only 2 minutess. The Pd-NP/MWCNT materials serve as efficient catalysts in C-C coupling as well as in hydrogenation reactions, all characterized by high conversion rates using a small amount of catalysts, high turnover frequency values and good recyclbility.Financial support from the Spanish Ministerio de Ciencia e
Innovación (MICINN) and the European Regional Development
Fund (ERDF) under projects CTQ2008-01784 and
MAT2007-66927-C02-01, and the Gobierno de Aragón (DGAPI086-
08) is gratefully acknowledged. M.C. thanks MICINN
for her Grant No. BES-2008-003503.Peer reviewe
Characterization of Non-Derivatized Cellulose Samples by Size Exclusion Chromatography in Tetrabutylammonium Fluoride/Dimethylsulfoxide (TBAF/DMSO)
International audienceThis paper deals with the use of tetrabutylammonium fluoride/dimethylsulfoxide (TBAF/DMSO) to characterize the molar mass distribution of non-derivatized cellulosic samples by size exclusion chromatography (SEC). Different cellulose samples with various average degree of polymerization (DP) were first solubilized in this solvent system, with increasing TBAF rates, and then analyzed by SEC coupled to a refractive index detector (RID), using DMSO as mobile phase. The Molar Masses (MM) obtained by conventional calibration were then discussed and compared with suppliers’ data and MM determined by viscosimetry measurements. By this non-classic method, molar mass of low DP samples (Avicel® and cotton fibers) have been determined. For high DP samples (α-cellulose and Vitacel®), dissolution with TBAF concentration of 10 mg/mL involved elution of cellulose aggregates in the exclusion volume, related to an incomplete dissolution or the dilution of TBAF molecules in elution solvent, preventing the correct evaluation of their molar mass
LGWP & HC Refrigerants Solubility Tests Performed in Running Scroll Compressor
This paper presents the results of investigations on Low Global Warming Potential refrigerants and R290 solubility with different lubricants. Solubility impacts a lot the final lubricant-refrigerant mixture reaching the bearing lubricant inlet and in the same way can impact compressor reliability on wet vapor flowing back to compressor inlet Experimental data, measured in operating compressors, are compared to static steady state values coming from PVT plots. R407C and R410A, two well-known HFC refrigerants, are added as a reference. This work highlights the differences between dynamic solubility (tests performed in a compressor) and static solubility (from PVT plots). A comparison of the impact on the dynamic solubility has been done when a steering feature is added. This work allows us to define the best compromise between different lubricants in these new applications
Détection d'arcs électriques séries par analyse temps-fréquence et traitement morphologique
- Les arcs électriques séries peuvent endommager gravement les installations électriques, voire provoquer des incendies. Cet article décrit une méthode de détection des arcs séries basée sur l'analyse de la dérivée du courant. Une Représentation Temps-Fréquence (RTF) de ce signal (spectrogramme glissant) permet de mettre en évidence des motifs caractéristiques des arcs séries. Un traitement morphologique simple permet d'extraire les motifs d'arcs de la RTF et de quantifier l'importance du phénomène sous la forme d'un « degré de présence d'arc série »
LOLINA MARTINÓN DE CARNAVAL [Material gráfico]
ÁLBUM FAMILIAR CASA DE COLÓNCopia digital. Madrid : Ministerio de Educación, Cultura y Deporte. Subdirección General de Coordinación Bibliotecaria, 201
Russian roulette with unlicensed fat-burner drug 2,4-dinitrophenol (DNP) : evidence from a multidisciplinary study of the internet, bodybuilding supplements and DNP users
BACKGROUND:
2,4-Dinitrophenol (DNP) poses serious health-risks to humans. The aims of this three-stage multidisciplinary project were, for the first time, to assess the risks to the general public from fraudulent sale of or adulteration/contamination with DNP; and to investigate motives, reasons and risk-management among DNP-user bodybuilders and avid exercisers.
METHODS:
Using multiple search-engines and guidance for Internet research, online retailers and bodybuilding forums/blogs were systematically explored for availability of DNP, advice offered on DNP use and user profiles. Ninety-eight pre-workout and weight-loss supplements were purchased and analysed for DNP using liquid-chromatography-mass-spectrometry. Psychosocial variables were captured in an international sample of 35 DNP users (26.06 ± 6.10 years, 94.3 % male) with an anonymous, semi-qualitative self-reported survey.
RESULTS:
Although an industrial chemical, evidence from the Internet showed that DNP is sold 'as is', in capsules or tablets to suit human consumption, and is used 'uncut'. Analytical results confirmed that DNP is not on the supplement market disguised under fictitious supplement names, but infrequently was present as contaminant in some supplements (14/98) at low concentration (<100mcg/kg). Users make conscious and 'informed' decisions about DNP; are well-prepared for the side-effects and show nonchalant attitude toward self-experimentation with DNP. Steps are often taken to ensure that DNP is genuine. Personal experience with performance- and appearance enhancing substances appears to be a gateway to DNP. Advice on DNP and experiences are shared online. The significant discrepancy between the normative perception and the actual visibility suggests that DNP use is-contrary to the Internet accounts-a highly concealed and lonesome activity in real life. Positive experiences with the expected weight-loss prevail over the negative experiences from side effects (all but two users considered using DNP again) and help with using DNP safely is considered preferable over scare-tactics.
CONCLUSION:
Legislation banning DNP sale for human consumption protects the general public but DNP is sold 'as is' and used 'uncut' by determined users who are not dissuaded from experimenting with DNP based on health threats. Further research with stakeholders' active participation is imperative for targeted, proactive public health policies and harm-reduction measures for DNP, and other illicit supplements
Study of Viscoelastic Effect on the Frequency Shift of Microcantilever Chemical Sensors (journal article)
Microcantilevers coated with a chemically sensitive layer are increasingly being used in chemical detection systems. The sensitive coating, often a polymer, absorbs specific molecules, which can be detected by monitoring the shift in the mechanical resonant frequency. Usually. the frequency shift resulting from molecular absorption is interpreted as a mass loading effect. However, mass loading is not the only effect that has an impact on the frequency shift; the viscoelastic properties of the sensitive coating also are affected by the sorption process. Sorption-induced modulus changes are typically difficult to characterize. However, it is known that the sorption of analyte molecules in a polymer coating results in the plasticization of the coating. In most cases, the polymer becomes more rubbery with increasing concentration of analyte molecules, i.e., the coating becomes softer with increasing loss modulus, and the storage modulus decreases. Using a new analytical model developed for the resonant frequency expression of a hybrid microcantilever (elastic base and viscoelastic layer), the effects of the modification of the storage and loss moduli of the sensitive layer on the resonant frequency are examined. The main conclusion of this analytical study is that, even if the sensitive coating moduli are small compared to the base cantilever\u27s Young\u27s modulus, the effect of the change in the viscoelastic coating properties could contribute significantly to the overall frequency shift (8-23% in the simulations depending on the coating thickness, with even higher contributions for other sets of problem parameters
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