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Search Results: 1 - 10 of 6716 matches for " Luc Bergé "
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Levels of Genotoxic and Carcinogenic Ingredients in Plant Food Supplements and Associated Risk Assessment  [PDF]
Suzanne J. P. L. van den Berg, Patrizia Restani, Marelle G. Boersma, Luc Delmulle, Ivonne M. C. M. Rietjens
Food and Nutrition Sciences (FNS) , 2011, DOI: 10.4236/fns.2011.29134
Abstract: The present study describes the selection, analysis and risk assessment of genotoxic and carcinogenic ingredients of botanicals and botanical preparations which can be found in food and plant food supplements (PFS). First an inventory was made of botanical ingredients that are of possible concern for human health because of their genotoxic and/or carcinogenic properties. In total, 30 botanical ingredients were selected and subsequently judged for their actual genotoxic and/or carcinogenic potential. Among the 30 compounds considered, 18 compounds were judged to be both genotoxic and carcinogenic. Interestingly, the majority of these compounds belong to the group of alkenylbenzenes or unsaturated pyrrolizidine alkaloids. Subsequently, based on available carcinogenicity data and estimated daily human exposure that was determined focusing on the intake from PFS, the Margin of Exposure (MOE) was calculated for the alkenylbenzenes estragole, methyleugenol, safrole and β-asarone. Calculating the MOEs for intake estimates of these alkenylbenzenes from PFS resulted in MOE values that were generally lower than 10,000 and often lower than 100. In some cases the MOE was even below 10 meaning that the estimated daily intake is in the range of dose levels causing malignant tumors in experimental animals. This result indicates that the use of PFS containing the genotoxic carcinogens estragole, methyleugenol, safrole or β-asarone might raise a potential concern for human health and would be of high priority for risk management.
Filamentation of ultrashort laser pulses in silica glass and KDP crystal: A comparative study
Jérémie Rolle,Luc Bergé,Guillaume Duchateau,Stefan Skupin
Physics , 2014, DOI: 10.1103/PhysRevA.90.023834
Abstract: Ionizing 800-nm femtosecond laser pulses propagating in silica glass and in potassium dihydrogen phosphate (KDP) crystal are investigated by means of a unidirectional pulse propagation code. Filamentation in fused silica is compared with the self-channeling of light in KDP accounting for the presence of defect states and electron-hole dynamics. In KDP, laser pulses produce intense filaments with higher clamping intensities up to 200 TW/cm$^2$ and longer plasma channels with electron densities above $10^{16}$ cm$^{-3}$. Despite these differences, the propagation dynamics in silica and KDP are almost identical at equivalent ratios of input power over the critical power for self-focusing.
The signature of dissipation in the mass-size relation: are bulges simply spheroids wrapped in a disc?
Trystyn A. M. Berg,Luc Simard,J. Trevor Mendel,Sara L. Ellison
Physics , 2014, DOI: 10.1093/mnrasl/slu026
Abstract: The relation between the stellar mass and size of a galaxy's structural subcomponents, such as discs and spheroids, is a powerful way to understand the processes involved in their formation. Using very large catalogues of photometric bulge+disc structural decompositions and stellar masses from the Sloan Digital Sky Survey Data Release Seven, we carefully define two large subsamples of spheroids in a quantitative manner such that both samples share similar characteristics with one important exception: the 'bulges' are embedded in a disc and the 'pure spheroids' are galaxies with a single structural component. Our bulge and pure spheroid subsample sizes are 76,012 and 171,243 respectively. Above a stellar mass of ~$10^{10}$ M$_{\odot}$, the mass-size relations of both subsamples are parallel to one another and are close to lines of constant surface mass density. However, the relations are offset by a factor of 1.4, which may be explained by the dominance of dissipation in their formation processes. Whereas the size-mass relation of bulges in discs is consistent with gas-rich mergers, pure spheroids appear to have been formed via a combination of 'dry' and 'wet' mergers.
Spectral self-action of THz emission from ionizing two-color laser pulses in gases
Eduardo Cabrera-Granado,Yxing Chen,Ihar Babushkin,Luc Bergé,Stefan Skupin
Physics , 2014, DOI: 10.1088/1367-2630/17/2/023060
Abstract: The spectrum of terahertz (THz) emission in gases via ionizing two-color femtosecond pulses is analyzed by means of a semi-analytic model and finite-difference-time-domain simulations in 1D and 2D geometries. We show that produced THz signals interact with free electron trajectories and thus influence significantly further THz generation upon propagation, i.e., make the process inherently nonlocal. This self-action plays a key role in the observed strong spectral broadening of the generated THz field. Diffraction limits the achievable THz bandwidth by efficiently depleting the low frequency amplitudes in the propagating field.
Directionality of THz emission from photoinduced gas plasmas
Christian K?hler,Eduardo Cabrera-Granado,Ihar Babushkin,Luc Bergé,Joachim Herrmann,Stefan Skupin
Physics , 2011, DOI: 10.1364/OL.36.003166
Abstract: Forward and backward THz emission by ionizing two-color laser pulses in gas is investigated by means of a simple semi-analytical model based on Jefimenko's equation and rigorous Maxwell simulations in one and two dimensions. We find the emission in backward direction having a much smaller spectral bandwidth than in forward direction and explain this by interference effects. Forward THz radiation is generated predominantly at the ionization front and thus almost not affected by the opacity of the plasma, in excellent agreement with results obtained from a unidirectional pulse propagation model.
On the Saturation of the Nonlinear Refractive Index in Atomic Gases
Christian K?hler,Roland Guichard,Emmanuel Lorin,Szczepan Chelkowski,André D. Bandrauk,Luc Bergé,Stefan Skupin
Physics , 2013, DOI: 10.1103/PhysRevA.87.043811
Abstract: Motivated by the ongoing controversy on the origin of the nonlinear index saturation and subsequent intensity clamping in femtosecond filaments, we study the atomic nonlinear polarization induced by a high-intensity and ultrashort laser pulse in hydrogen by numerically solving the time dependent Schr\"odinger equation. Special emphasis is given to the efficient modeling of the nonlinear polarization at central laser frequency corresponding to 800 nm wavelength. Here, the recently proposed model of the Higher-Order Kerr Effect (HOKE) and two versions of the Standard model for femtosecond filamentation, including either a multi-photon or tunnel ionization rate, are compared. We find that around the clamping intensity the instantaneous HOKE model does not reproduce the temporal structure of the nonlinear response obtained from the quantum mechanical results. In contrast, the non-instantaneous charge contributions included in the Standard models ensure a reasonable quantitative agreement. Therefore, the physical origin for the observed saturation of the overall electron response is confirmed to mainly result from contributions of free or nearly free electrons.
Process Adaption and Modifications of a Nutrient Removing Wastewater Treatment Plant in Sri Lanka Operated at Low Loading Conditions  [PDF]
Johanna Berg, Stig Morling
Materials Sciences and Applications (MSA) , 2013, DOI: 10.4236/msa.2013.45038
Abstract:

The Sri Lankan national water authority, that is The National Water Supply and Drainage Board (NWS&DB) has taken a new wastewater treatment plant into operation at Ja Ela, North of Colombo. The plant has been in operation since September 2011. In April 2012, it was concluded how a test of the aeration efficiency and a performance test should be carried out. The tests have been based on the actual loading of the plant and the analysis results from the daily process control. The evaluation of the aeration efficiency is not reported in this paper. The paper presents the overall performance of the water treatment part of the plant during start-up conditions, from fall 2011 through the first five months of 2012. The results from the operation are found in Table 1. An important circumstance at the plant is the current very low loading in comparison with the design load. This fact has resulted in an introduction of an intermittent mode of the aeration (nitrification) reactor. Based on operation figures, during more than a month (May 2012), it has been possible to give a realistic assessment of the overall performance. The most striking results are summarized as follows: 1) The intermittent operation has enabled an energy efficient operation of the plant. By the introduction of the intermittent aeration, the energy consumption has been reduced by around 75%, compared with the continuous operation mode; 2) The plant performance during the intermittent operation has been improved with respect to virtually all important pollu

Reliability of High Speed Ultra Low Voltage Differential CMOS Logic  [PDF]
Omid Mirmotahari, Yngvar Berg
Circuits and Systems (CS) , 2015, DOI: 10.4236/cs.2015.65013
Abstract: In this paper, we present a solution to the ultra low voltage inverter by adding a keeper transistor in order to make the semi-floating-gate more stable and to reduce the current dissipation. Moreover, we also present a differential ULV inverter and elaborate on the reliability and fault tolerance of the gate. The differential ULV gate compared to both a former ULV gate and standard CMOS are given. The results are obtained through Monte-Carlo simulations.
The Show-Up Identification Procedure: A Literature Review  [PDF]
Mattias Per Sj?berg
Open Journal of Social Sciences (JSS) , 2016, DOI: 10.4236/jss.2016.41012
Abstract: A show-up is an identification procedure that only presents the witness with one suspect in contrast to a lineup where the suspect is presented among a number of fillers (i.e., known innocent people). This feature makes the show-up procedure very suggestive. In this literature review, an overview of the current research about this identification procedure is presented. The different factors that influence the accuracy in show-up procedures are separated into system (e.g., clothing bias, instruction bias, and the impact of multiple show-ups) and estimator variables (e.g., age, cross-race effects, and alcohol) in line with Wells [1]. The implications of the research are discussed together with suggestions for future research.
The Voices of Young Sexual Offenders in Norway: A Qualitative Study  [PDF]
Marita Sandvik, Merete Berg Nesset, Anita Berg, Erik S?ndenaa
Open Journal of Social Sciences (JSS) , 2017, DOI: 10.4236/jss.2017.52009
Abstract: Adolescents commit around 20 - 30 percent of all sexual offences and attempts have been made in the literature to distinguish between types of young sexual offenders. This study describes the understanding of nine Norwegian young male sexual offenders regarding sexual offences committed by them during adolescence, their childhood experiences and their suggestions on how to prevent juvenile sexual offending. The participants were interviewed with individual, semi-structured interviews and the rich data were analyzed with systematic text condensation. The young offenders’ understanding of mutuality in the relationship with their minor victim contributed to the sexual offence. Moreover, moral immaturity, learning difficulties or being a refugee, exposure to child pornography, impulsivity and high sexual arousal were described as having impacted on their offending. Findings suggest the need for further studies to understand the risk factors for juvenile sexual offending. Better knowledge about the legal framework of a sexual relationship and consequences of sexual abuse for both offenders and victims were highlighted to be the most important measure to prevent sexual abuse by juveniles in general.
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