10,665 research outputs found
Energies for the high- L rydberg states of helium: Asymptotic analysis
The asymptotic expansion method based on a core polarization potential for the Rydberg electron is reviewed and extended to the high angular momentum states of helium up to L=15. A comparison with recent large-scale configuration interaction calculations for the nonrelativistic energies shows that there is good agreement for L=7, but there are serious systematic disagreements for the states of higher angular momentum. A possible explanation is that there is an important class of configurations missing from the CI calculations. © 2009 The American Physical Society
RASSF1 Polymorphisms in Cancer
Ras association domain family 1A (RASSF1A) is one of the most epigenetically silenced elements in human cancers. Localized on chromosome 3, it has been demonstrated to be a bone fide tumor suppressor influencing cell cycle events, microtubule stability, apoptosis, and autophagy. Although it is epigenetically silenced by promoter-specific methylation in cancers, several somatic nucleotide changes (polymorphisms) have been identified in RASSF1A in tissues from cancer patients. We speculate that both nucleotide changes and epigenetic silencing result in loss of the RASSF1A tumor suppressor function and the appearance of enhanced growth. This paper will summarize what is known about the origin of these polymorphisms and how they have helped us understand the biological role of RASSF1A
Individual Private Retirement Insurances: holding behaviours among pensioners
International audienceIn the current context of demographic pressures, reforms of PAYG pension systems increase the extent to which individuals are responsible for their own retirement planning. The French pension system offered high replacement rates. The population used to consider that the State scheme had to provide them with an adequat level of pension. In 2003, the pension reform implemented individual and professional pension plans. These retirement savings contracts are not well developed. However, we observed that individuals prefer contracting life endowment contracts, which are long term savings supports, to prepare retirement. Using econometric specifications, we intend to put into perspective the households and individual characteristics which explain the holding behaviours of life endowment contracts and retirement savings plans. We conclude that the highest professional categories and the most educated individuals hold more frequently and simultanesously both types of contracts
Low frequency variability in the lower St. Lawrence Estuary
The lower St. Lawrence Estuary is a good example of wide estuaries with a second lateral boundary within several internal Rossby radii. We compare direct measurements from the 1979 lower St. Lawrence estuary mesoscale current meter array with satellite thermal images observed during the same period. The current field appears to show two quasi-steady states: one configuration is characterized by strong outflow along the north shore of the estuary with a transverse front at the mouth. The other current pattern is more typical of estuaries, with inflow along the north shore and outflow along the south shore. Transitions between these configurations are likely to be due to instability of the current field
Daleel:simplifying cloud instance selection using machine learning
Decision making in cloud environments is quite challenging due to the diversity in service offerings and pricing models, especially considering that the cloud market is an incredibly fast moving one. In addition, there are no hard and fast rules; each customer has a specific set of constraints (e.g. budget) and application requirements (e.g. minimum computational resources). Machine learning can help address some of the complicated decisions by carrying out customer-specific analytics to determine the most suitable instance type(s) and the most opportune time for starting or migrating instances. We employ machine learning techniques to develop an adaptive deployment policy, providing an optimal match between the customer demands and the available cloud service offerings. We provide an experimental study based on extensive set of job executions over a major public cloud infrastructure
AC volume breakdown and surface flashover of a 4% NovecTM 4710/96% CO2 gas mixture compared to CO2 in highly nonhomogeneous fields
AC pre-discharge currents, breakdown, and flashover voltage measurements are reported in a 10 mm needle-plane arrangement in a 4% NovecTM 4710/96% CO2 gas mixture and compared with CO2 for pressures up to 8.8 bar abs. Flashover measurements were performed on different solid dielectrics (Al2O3_filled epoxy resins, PTFE (Polytetrafluoroethylene) and PE (polyethylene)) for different roughness surface finishes. The effect of fixed conducting needles at various positions on electrical strength is reported. A strong nonlinear behaviour as function of gas pressure was observed for all the studied parameters (gas, needle position, solid insulator, insulator roughness). The non-linear behaviour is attributed to the inception and quenching of glow corona, in the interval between inception and breakdown or flashover voltages. It is found that a 4% concentration of NovecTM 4710 in CO2 has a breakdown/flashover voltage ≈ 1.14 higher than CO2. The glow corona-induced stabilization effect is seen for pressures between 2 and 5 bar abs for all the studied parameters. The peak flashover voltage and its associated pressure of the different insulators are strongly dependent on surface roughness. At 8.8 bar abs, the flashover voltage level obtained with various materials was ordered as follows: PTFE > PE-UHMW > Epoxy > HDPE(High-density polyethylene)
An Analytical Two Resistance Mass Transfer Model for Dye Adsorption on Bagasse Pith
The adsorption of fOUr dyes, namely, Basic Blue 69, Basic Red 22, Acid Blue 25 and Acid Red 114, onto
bagasse pith has been studied. A mass transfer model, based on external mass transport and p01-e diffusion,
has been used to correlate experimental and theoretical concentration versus time data. The model is an
analytical solution which may be applied to adsorption systems in which the operating line and tie lines all
terminate on the saturation plateau of the equilibrium isothenn. A single external mass transfer coefficient
and a single p01'e diffusion coefficient were sufficient to describe each sytem fOT several initial dye concentrations
and several pith masses. The external coefficient were 9.0 x 1(F3, 8.0 x 1(F3, 1.0 x 1(F3 and 1.5 x 10J cm
S·I, the pOTe diffusivities were 5.5 x 1(F", 2.5 x 1(F", 2.2 x 1(F7 and 4.5 x l(Fi cm2 S·l for Basic Blue 69,
Basic Red 22, Acid Blue 25 and Acid Red 114, respectively
Directed Irradiation Synthesis as an Advanced Plasma Technology for Surface Modification to Activate Porous and “as-received” Titanium Surfaces
For the design of smart titanium implants, it is essential to balance the surface properties without any detrimental effect on the bulk properties of the material. Therefore, in this study, an irradiation-driven surface modification called directed irradiation synthesis (DIS) has been developed to nanopattern porousand“as-received”c.p. Tisur faces with the aim of improving cellular viability. Nano features were developed using singly-charged argon ions at 0.5 and 1.0 keV energies, incident angles from 0◦ to 75◦ degrees, and fluences up to 5.0×1017 cm−2. Irradiated surfaces were evaluated by scanning electron microscopy, atomic force microscopy and contact angle, observing an increased hydrophilicity (a contact angle reduction of 73.4% and 49.3%) and a higher roughness on both surfaces except for higher incident angles, which showed the smoothest surface. In-vitro studies demonstrated the biocompatibility of directed irradiation synthesis (DIS) reaching 84% and 87% cell viability levels at 1 and 7 days respectively, and a lower percentage of damaged DNA in tail compared to the control c.p. Ti. All these results confirm the potential of the DIS technique to modify complex surfaces at the nanoscale level promoting their biological performance.Department of Defense (Spain) contract W81XWH-11-2-0067Ministry of Economy and Competitiveness of Spain grant MAT2015-71284-
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