Ion sense of polarization of the electromagnetic wave field in the electron whistler frequency band

International audienceIt is shown that the left-hand (or ion-type) sense of polarization can appear in the field interference pattern of two plane electron whistler waves. Moreover, it is demonstrated that the ion-type polarized wave electric fields can be accompanied by the presence at the same observation point of electron-type polarized wave magnetic fields. The registration of ion-type polarized fields with frequencies between the highest ion gyrofrequency and the electron gyrofrequency in a cold, overdense plasma is a sufficient indication for the existence of an interference wave pattern, which can typically occur near artificial or natural reflecting magnetospheric plasma regions, inside waveguides (as in helicon discharges, for example), in fields resonantly emitted by beams of charged particles or, in principle, in some self-sustained, nonlinear wave field structures. A comparison with the conventional spectral matrix data processing approach is also presented in order to facilitate the calculations of the analyzed polarization parameters

Biomedical applications of Raman and infrared spectroscopy to diagnose tissues

The objective of the article is to review biomedical applications which became possible after the development of sensitive and high throughput Raman and Fourier transform infrared spectrometers in the past decade. Technical aspects of the instrumentation are briefly described. Then the broad range of vibrational spectroscopic applications with the focus on imaging and fiber-optical methods are discussed to study mineralized tissue (bone, teeth), skin, brain, the gastrointestinal tract (mouth, pharynx, esophagus, colon), breast, arteries, cartilage, cervix uteri, the urinary tract (prostate, bladder), lung, ocular tissue, liver, heart and spleen. Experimental studies are summarized demonstrating the possibilities and prospects of these methods in various fields of biodiagnostics to detect and characterize diseases, tumors and other pathologies

Driver Accelerator Design for the 10 kW Upgrade of the Jefferson Lab IR FEL

An upgrade of the Jefferson Lab IR FEL is now under construction. It will provide 10 kW output light power in a wavelength range of 2-10 microns. The FEL will be driven by a modest-sized 80-210 MeV, 10 mA energy-recovering superconducting RF (SRF) linac. Stringent phase space requirements at the wiggler, low beam energy, and high beam current subject the design to numerous constraints. These are imposed by the need for both transverse and longitudinal phase space management, the potential impact of collective phenomena (space charge, wakefields, beam break-up (BBU), and coherent synchrotron radiation (CSR)), and interactions between the FEL and the accelerator RF system. This report addresses these issues and presents an accelerator design solution meeting the requirements imposed by physical phenomena and operational necessities.Comment: submission THC03 for LINAC200

Introducing the Egypt Labor Market Panel Survey 2018

This paper introduces the 2018 wave of the Egypt Labor Market Panel Survey (ELMPS), previously fielded in 1998, 2006, and 2012. The ELMPS has already become the primary source of data for a large number of scholarly and policy studies on the labor market and human development issues in Egypt, and this new wave will further enhance its value as a critical data public good. This longitudinal survey is nationally representative, tracking both households and individuals over two decades. In this paper, we describe the key characteristics of the 2018 wave, including sampling, fielding, and questionnaire design. Changes in the collection of retrospective data starting in 2018 are discussed, and we demonstrate that they improved the data quality. We examine the patterns of attrition and present the construction of weights designed to correct for attrition, as well as to ensure that the sample remains nationally representative. We compare the ELMPS data with other Egyptian data sources, namely, the 2017 Census and various rounds of the Labor Force Survey (LFS). The data provide important new insights into Egypt's labor market, economy, and society

Longitudinal phase space manipulation in energy recovering linac-driven free-electron lasers

Energy recovering an electron beam after it has participated in a free-electron laser (FEL) interaction can be quite challenging because of the substantial FEL-induced energy spread and the energy anti-damping that occurs during deceleration. In the Jefferson Lab infrared FEL driver-accelerator, such an energy recovery scheme was implemented by properly matching the longitudinal phase space throughout the recirculation transport by employing the so-called energy compression scheme. In the present paper,after presenting a single-particle dynamics approach of the method used to energy-recover the electron beam, we report on experimental validation of the method obtained by measurements of the so-called "compression efficiency" and "momentum compaction" lattice transfer maps at different locations in the recirculation transport line. We also compare these measurements with numerical tracking simulations.Comment: 31 pages, 13 figures, submitted to Phys. Rev. Special Topics A&

Interaction of Tet Repressor with Operator DNA and with Tetracycline Studied by Infrared and Raman Spectroscopy

AbstractTet repressor (TetR) is involved in the most abundant mechanism of tetracycline (Tc) resistance of Gram-negative bacteria. Raman spectra were measured for the class D TetR protein, for an oligodeoxyribonucleotide with sequence corresponding to operator site O1, and for the TetR:oligonucleotide complex. TetR forms a complex with [Ni-Tc]+, which does not bind to operator DNA. Raman and infrared measurements indicate nearly identical conformations of TetR with and without [Ni-Tc]+. Differences between the experimental spectrum of the TetR:operator DNA complex and the computed sum of the component spectra provide direct spectroscopic evidence for changes in DNA backbone torsions and base stacking, rearrangement of protein backbone, and specific contacts between TetR residues and DNA bases. Complex formation is connected with intensity decrease at 1376cm−1 (participation of thymine methyl groups), intensity increase at 1467cm−1 (hydrogen bond formation at guanine N7), decreased intensity ratio I854/I823 (increased hydrophobicity of tyrosine environment), increased intensity at 1363cm−1 (increased hydrophobicity of tryptophan ring environment), differences in the range 670–833cm−1 (changes in B-DNA backbone torsions and base stacking), and decreased intensity of the amide I band (structural rearrangement of TetR backbone consistent with a reduction of the distance between the two binding helices)

Waveforms of Langmuir turbulence in inhomogeneous solar wind plasmas

International audienceModulated Langmuir waveforms have been observed by several spacecraft in various regions of the heliosphere, such as the solar wind, the electron foreshock, the magnetotail, or the auroral ionosphere. Many observations revealed the bursty nature of these waves, which appear to be highly modulated, localized, and clumped into spikes with peak amplitudes typically 3 orders of magnitude above the mean. The paper presents Langmuir waveforms calculated using a Hamiltonian model describing self-consistently the resonant interaction of an electron beam with Langmuir wave packets in a plasma with random density fluctuations. These waveforms, obtained for different profiles of density fluctuations and ranges of parameters relevant to solar type III electron beams and plasmas measured at 1 AU, are presented in the form they would appear if recorded by a satellite moving in the solar wind. Comparison with recent measurements by the STEREO and WIND satellites shows that their characteristic features are very similar to the observations

New methodology to process shifted excitation Raman difference spectroscopy data : a case study of pollen classification

Shifted excitation Raman difference spectroscopy (SERDS) is a background correction method for Raman spectroscopy. Here, the difference spectra were directly used as input for SERDS-based classification after an optimization procedure to correct for photobleaching of the autofluorescence. Further processing included a principal component analysis to compensate for the reduced signal to noise ratio of the difference spectra and subsequent classification by linear discriminant analysis. As a case study 6,028 Raman spectra of single pollen originating from plants of eight different genera and four different growth habits were automatically recorded at excitation wavelengths 784 and 786 nm using a high-throughput screening Raman system. Different pollen were distinguished according to their growth habit, i.e. tree versus non-tree with an accuracy of 95.9%. Furthermore, all pollen were separated according to their genus, providing also insight into similarities based on their families. Classification results were compared using spectra reconstructed from the differences and raw spectra after state-of-art baseline correction as input. Similar sensitivities, specificities, accuracies and precisions were found for all spectra with moderately background. Advantages of SERDS are expected in scenarios where Raman spectra are affected by variations due to detector etaloning, ambient light, and high background

High-throughput screening Raman microspectroscopy for assessment of drug-induced changes in diatom cells

High-throughput screening Raman spectroscopy (HTS-RS) with automated localization algorithms offers unsurpassed speed and sensitivity to investigate the effect of dithiothreitol on the diatom Phaedactylum tricornutum. The HTS-RS capability that was demonstrated for this model system can be transferred to unmet analytical applications such as kinetic in vivo studies of microalgal assemblages. © 2019 The Royal Society of Chemistry

JOINT LOADING AT DIFFERENT VARIATIONS OF SQUATS

The purpose of this study was to identify the effect of squatting in a common, in a knee-shifted position and in an inclined position (3 cm heel lift) on joint loading. 16 male subjects were tested during squatting with an additional mass of 20 kg. Kinematic and kinetic recordings were performed by two force platforms (AMTI) and a ten infrared camera system (VICON). Inverse dynamics were calculated using a recursive multibody algorithm. Results showed significantly higher ankle dorsiflexion moments as well as higher knee varus moments for the knee-shifted performance. Due to the higher load on the ankle and the knee joint the knee-shifted variation should be avoided in squat training. The inclination of 3 cm does not lead to alterations of the joint moments and therefore does not lead to beneficial effects with respect to joint loading