bluuebunny/crossref_metadata_2025 huggingface dataset:
Dust properties of double-tailed active asteroid (6478) Gault
Authors: Moreno F. , Jehin E. , Licandro J. , Ferrais M. , Moulane Y. , Pozuelos F. J. , Manfroid J. , Devogèle M. , Benkhaldoun Z. , Moskovitz N. , Popescu M. , Serra-Ricart M. , Cabrera-Lavers A. , Monelli M.
Published: April 2019

Context. Asteroid (6478) Gault was discovered to exhibit a comet-like tail in observations from December 2018, becoming a new member of the so-called active asteroid population in the main asteroid belt.

Aims. We seek to investigate the grain properties of the dust ejected from asteroid (6478) Gault and to give insight into the activity mechanism(s).

Methods. We use a Monte Carlo dust tail brightness code to retrieve the dates of dust ejection, the physical properties of the grains, and the total dust mass losses during each event. The code takes into account the brightness contribution of the asteroid itself. The model is applied to a large data set of images spanning the period from 2019 January 11 to 2019 March 13. In addition, we carried out both short- and long-term photometric measurements of the asteroid.

Results. It is shown that, to date, asteroid (6478) Gault has experienced two episodes of impulsive dust ejection, which took place around 2018 November 5 and 2019 January 2. These two episodes released at least 1.4 × 107 kg and 1.6 × 106 kg of dust, respectively, at escape speeds. The size distribution, consisting of particles in the 1 μm–1 cm radius range, follows a broken power law with bending points near 15 μm and 870 μm. On the other hand, the photometric series indicate a nearly constant magnitude over several 5–7.3 h periods, which is a possible effect of the masking of a rotational light curve by the dust.

Conclusions. The dust particles forming Gault’s tails were released from the asteroid at escape speeds, but the specific ejection mechanism is unclear until photometry of the dust-free asteroid are conducted to assess whether this was related to rotational disruption or to other possible causes.
Terrestrial deuterium-to-hydrogen ratio in water in hyperactive comets
Authors: Lis Dariusz C. , Bockelée-Morvan Dominique , Güsten Rolf , Biver Nicolas , Stutzki Jürgen , Delorme Yan , Durán Carlos , Wiesemeyer Helmut , Okada Yoko
Published: April 2019

The D/H ratio in cometary water has been shown to vary between 1 and 3 times the Earth’s oceans value, in both Oort cloud comets and Jupiter-family comets originating from the Kuiper belt. This has been taken as evidence that comets contributed a relatively small fraction of the terrestrial water. We present new sensitive spectroscopic observations of water isotopologues in the Jupiter-family comet 46P/Wirtanen carried out using the GREAT spectrometer aboard the Stratospheric Observatory for Infrared Astronomy (SOFIA). The derived D/H ratio of (1.61 ± 0.65)×10−4 is the same as in the Earth’s oceans. Although the statistics are limited, we show that interesting trends are already becoming apparent in the existing data. A clear anti-correlation is seen between the D/H ratio and the active fraction, defined as the ratio of the active surface area to the total nucleus surface. Comets with an active fraction above 0.5 typically have D/H ratios in water consistent with the terrestrial value. These hyperactive comets, such as 46P/Wirtanen, require an additional source of water vapor in their coma, explained by the presence of subliming icy grains expelled from the nucleus. The observed correlation may suggest that hyperactive comets belong to a population of ice-rich objects that formed just outside the snow line, or in the outermost regions of the solar nebula, from water thermally reprocessed in the inner disk that was transported outward during the early disk evolution. The observed anti-correlation between the active fraction and the nucleus size seems to argue against the first interpretation, as planetesimals near the snow line are expected to undergo rapid growth. Alternatively, isotopic properties of water outgassed from the nucleus and icy grains may be different due to fractionation effects at sublimation. In this case, all comets may share the same Earth-like D/H ratio in water, with profound implications for the early solar system and the origin of Earth’s oceans.
Rivalités et arrangements coopératifs pour l’accès à l’eau souterraine dans la plaine de Berrechid au Maroc
Authors: Ouassissou Romaïssa , Kuper Marcel , Dugué Patrick , El Amrani Mohamed , Hammani Ali , Ameur Fatah
Published: April 2019

Au Maroc, l’exploitation individuelle des eaux souterraines a permis le développement rapide d’une agriculture irriguée intensive. Dans la plaine de Berrechid, la ressource est limitée et surexploitée. L’agence de bassin tente depuis une dizaine d’années de mettre en place une contractualisation avec différents acteurs pour réguler les prélèvements en eau souterraine à usage agricole. L’objectif de l’étude est d’analyser en quoi la catégorisation des agriculteurs, se distinguant par leur accès à l’eau et au foncier, et les interactions entre ces catégories d’agriculteurs, sont utiles pour penser la gouvernance de la nappe. Une fois la dynamique de l’agriculture irriguée retracée, des enquêtes ont permis d’établir une typologie d’agriculteurs, puis les arrangements et rivalités entre les différents types d’agriculteurs ont été caractérisés. Les résultats montrent que l’utilisation accrue des eaux souterraines a déclenché des rivalités pour l’accès à l’eau, ainsi que l’exclusion de certains agriculteurs dans un contexte de baisse de la nappe. Pour dépasser ces problèmes d’accès, certains agriculteurs mettent en place des arrangements coopératifs autour des différents facteurs de production (eau, terre, capital, savoir-faire, main-d’œuvre). Cependant, ces arrangements accentuent, paradoxalement, la surexploitation de la nappe et les rivalités, et entraînent la poursuite et l’évolution des formes d’arrangements coopératifs. La compréhension fine de la nature des relations entre différents types d’agriculteurs peut permettre d’inclure une réflexion sur l’équité sociale dans le projet de concession aux associations de producteurs, qui pour le moment semble ignorer ces relations.
Determination of downy and powdery mildew resistance of some Vitis spp.
Authors: Yıldırım Zeynep , Atak Arif , Akkurt Murat
Published: April 2019

The Black Sea region of Turkey receives an annual rainfall of 2000-2500 mm and viticulture in the region depends on the rainfall limits significantly. In this study, the resistance of eighty different Vitis species and cultivars/genotypes to downy and powdery mildew was assessed using Marker Assisted Selection coupled with inoculation observations. Six Simple Sequence Repeats (SSR) and one Sequence Characterized Amplified Region (SCAR) markers were developed for different resistance loci (Run1, Rpv1, Ren1, Rpv3, Ren3) from different Vitis genetic resources. Eight of the cultivars/genotypes were characterised as resistant to downy mildew, seven were resistant to powdery mildew, and four were resistant to both diseases. These results, taken together with the disease inoculation observations, revealed ‘Köfteci Üzümü’ (Vitis labrusca) and ‘Giresun 3’ (Vitis labrusca) were the most resistant cultivars/genotypes.
High-energy mid-infrared femtosecond pulses at 3.3 μm directly generated by dual-chirped optical parametric amplification
Authors: Fu Yuxi , Nishimura Kotaro , Xue Bing , Suda Akira , Midorikawa Katsumi , Eiji J. Takahashi
Published: April 2019

By employing a dual-chirped optical parametric amplification (DC-OPA) using MgO:LiNbO3 crystals, we generate 31 mJ mid-infrared (MIR) pulses at 3.3 um with a repetition rate of 10 Hz. After passing through a CaF2 bulk compressor which has 70% throughput efficiency, these MIR pulses are compressed to 70 fs (6.3 optical cycles), which is close to the transform-limited duration of 66 fs. Thus, the peak power is evaluated to be 0.3 TW. Our results present notable progress in the generation of high-energy MIR pulses and prove that DC-OPA is a superior method for efficiently generating MIR pulses with few-cycle duration and TW-class peak power.
Towards a 10-fs hyperspectral spectroscopy source with arbitrary pulse shaping based on adiabatic frequency conversion
Authors: Heberle Dylan A. , Flemens Noah R. , Ding Xiaoyue , Chang Wei-Zung , Moses Jeffrey
Published: April 2019

We introduce a 10-fs hyperspectral source architecture for facilitating nonlinear spectroscopy with multi-color sequences of arbitrarily shaped 10-fs UV/Vis, near-IR, and mid-IR pulses. Design principles and initial experimental results are provided.
Circular dichroism in high harmonic generation from chiral molecules
Authors: Harada Yoichi , Haraguchi Eisuke , Kaneshima Keisuke , Sekikawa Taro
Published: April 2019

Circularly polarized high harmonic generation from a chiral molecule was found to significantly depend both on the chirality and on the rotating direction of the circularly polarized counter-rotating two-color driving laser fields.
Minimizing attosecond CEP jitter by carrier envelope phase tuning
Authors: Prandolini Mark. J. , Gaumnitz Thomas , Kothe Alexander , Henkel Jost , Schneider Joachim , Hengster Julia , Drescher Markus , Lein Manfred , Uphues Thorsten
Published: April 2019

Minimizing the CEP jitter of isolated attosecond pulses (IAP) will be important for future applications. This jitter is experimentally and theoretically investigated and can be minimized when the driving pulse is near its Fourier limit but with slightly negative chirp. Thus, understanding and characterization of the CEP jitter of IAPs is a first step towards exact control of the electric field of IAP pulses.
Atomic scale electronic structure and response in attosecond photoemission delays: A case study using non-centrosymmetric BiTeCl
Authors: Neb Sergej , Oberer Christian , Enns Walter , Gebauer Andreas , Müller Norbert , Dil J. Hugo , Chulkov Evgueni V. , Kabachnik Nikolay M. , Echenique Pedro M. , Kazansky Andrey K. , Heinzmann Ulrich , Pfeiffer Walter
Published: April 2019

Attosecond time-resolved photoemission from the differently terminated BiTeCl surfaces yield a photoelectron streaking that cannot be explained by bulk propagation effects alone. Instead, the atomic scale electronic structure and dynamical screening for both surface terminations have to be taken into account.
Polarization states of high-harmonics generated in silicon from elliptical drivers
Authors: Klemke Nicolai , Tancogne-Dejean Nicolas , Rossi Giulio M. , Yang Yudong , Mainz Roland E. , Di Sciacca Giuseppe , Rubio Angel , Kärtner Franz X. , Mücke Oliver D.
Published: April 2019

The polarization states of high-harmonics generated in silicon with elliptical excitation are studies. Circularly polarized harmonics are demonstrated with both circular and non-circular excitation, determined by crystal symmetry and the dynamical response of the system.
Direct imaging of ultrafast electron dynamics by X-ray sum frequency generation
Authors: Rouxel Jérémy R. , Kowalewski Markus , Benett Kochise , Mukamel Shaul
Published: April 2019

We present a nonlinear X-ray technique which provides a spatial electron density image of valence electron excitations. The technique combines a visible pump and an X-ray pulse and yields snapshots of the transition charge densities.
A new method to calculate ultrafast electron dynamics in molecules based on matrix product states
Authors: Frahm Lars-Hendrik , Pfannkuche Daniela
Published: April 2019

We propose a new method to describe electron dynamics in molecules on the scale of femtoseconds. It is based on factorizing the electronic wave function into a matrix product state and using this factorization to solve the time dependent Schrodinger equation.
Fluorescence-detected two-quantum and one-quantum-two-quantum 2D electronic spectros-copy of Rhodamine 700
Authors: Müller Stefan , Draeger Simon , Klosterhalfen Niklas , Brixner Tobias
Published: April 2019

We demonstrate the simultaneous acquisition of three fourth-order nonlinear signal contributions using a shot-to-shot-modulating pulse shaper and fluorescence detection. Beside the 1Q photon echo, two different species of two-quantum contributions can be isolated without any background via phase cycling.
Cavity-enhanced ultrafast two-dimensional spectroscopy using higher-order modes
Authors: Thomas K. Allison
Published: April 2019

We describe methods using frequency combs and cavities for recording two-dimensional ultrafast spectroscopy signals with high sensitivity. By coupling multiple frequency combs to modes of an optical resonator, cavity-enhanced 2D spectroscopy signals are naturally generated.
The nature of the ultrafast magnetic phase transition in nickel revealed by correlating EUV-MOKE and ARPES spectroscopies
Authors: Tao Zhensheng , You Wenjing , Tengdin Phoebe , Chen Cong , Shi Xun , Zusin Dmitriy , Zhang Yingchao , Gentry Christian , Blonsky Adam , Keller Mark , Openeer Peter , Kapteyn Henry , Murnane Margaret
Published: April 2019

By correlating time- and angle-resolved photoemission (Tr-ARPES) and time-resolved transverse- magneto-optical Kerr effect (Tr-TMOKE) measurements, both at extreme ultraviolet (EUV) wavelengths, we uncover the nature of the ultrafast photoinduced magnetic phase transition in Ni. This allows us to explain the ultrafast magnetic response of Ni at all laser fluences - from a small reduction of the magnetization at low laser fluences, to complete quenching at high laser fluences. We provide an alternative explanation to the fluence-dependent recovery timescales commonly observed in ultrafast magneto-optical spectroscopies on ferromagnets: it is due to the bulk-averaging effect and different depths of sample exhibit distinct dynamics, depending on whether a magnetic phase transition is induced. We also show evidence of two competing channels with two distinct timescales in the recovery process, that suggest the presence of coexisting phases in the material.
Ultrafast carrier interactions in metal-halide perovskites probed with two-dimensional electronic spectroscopy
Authors: Johannes M. Richter , Branchi Federico , Franco V. A. Camargo , Nagahara Tetsuhiko , Zhao Baodan , Richard H. Friend , Cerullo Giulio , Deschler Felix
Published: April 2019

We use 2D electronic spectroscopy with sub-10-fs resolution to probe carrier-carrier scattering in perovskites. We report excitation-density dependent thermalization times below 100-fs. Strong coupling with excitonic states further reveals sub-bandgap states with low oscillator strength.
Raman spectroscopy of graphene under ultrafast laser excitation
Authors: Ferrante Carino , Virga Alessandra , Benfatto Lara , Martinati Miles , De Fazio Domenico , Sassi Ugo , Fasolato Claudia , Ott Anna K. , Postorino Paolo , Yoon Duhee , Cerullo Giulio , Mauri Francesco , Ferrari Andrea C. , Scopigno Tullio
Published: April 2019

The out-of-equilibrium Raman response of graphene is addressed by pulsed laser excitation. Phonon spectrum is rationalized by revisiting the electron-phonon picture in the light of a transient broadening of the Dirac cone.
Terahertz driven amplification of coherent optical phonons in GaAs coupled to metallic dog-bone resonators
Authors: Woerner Michael , Somma Carmine , Reimann Klaus , Elsaesser Thomas , Brener Igal , Reno John L. , Yang Yuanmu , Liu Peter Q.
Published: April 2019

Two-dimensional terahertz spectroscopy on an AlAs/GaAs nanostructure covered by field-enhancing dog-bone resonators shows signatures of coherent optical phonon amplification. Amplification is due to stimulated phonon emission by a terahertz-driven electron current.
Ultrafast bi-excitonic dynamics and annihilation in molecular and mesoscopic systems
Authors: Malevich Pavel , Heshmatpour Constantin , Lincoln Craig N. , Ceymann Harald , Schreck Maximilian H. , Hauer Jürgen
Published: April 2019

We present 5th and 3rd order 2D spectra of a squarine trimer. Slowly decaying (τ = 0.8 ps) and intensity dependent features unique to the 5th order signal are attributed to exciton-exciton annihilation.
Monitoring hot exciton dissociation in hybrid lead halide perovskite films with sub-10 fs pulses
Authors: Ghosh Tufan , Aharon Sigalit , Etgar Lioz , Ruhman Sanford
Published: April 2019

Sub-10 fs pump-probe experiments on methylammonium lead halide (MAPbI3) perovskite films show hot exciton dissociation in 20 fs after photo-excitation with ~0.7 eV excess energy compared to its optical band gap (BG). Coherent wave packets were also detected in the form of spectral modulation, revealing electron-phonon coupling in these materials. The estimated electron-phonon coupling strengths from the frequency and amplitude of the detected spectral modulation are in the weak regime, suggesting formation of large polaron.
Excitation and control of spin waves in FeBO3 by a strong-field THz pulse
Authors: Calendron Anne-Laure , Kueny Emma , Song Liwei , Cirmi Giovanni , Bocklage Lars , Kärtner Franz X. , Röhlsberger Ralf
Published: April 2019

The dynamically resolved response of the canted-antiferromagnet FeBO3 excited near a magnon resonance shows fast oscillations after THz-excitation’ followed by the magnons’ intrinsic relaxation’ enabling to probe transient magnetic relaxation dynamics over large frequency range.
Antiresonant-like behavior in carrier-envelope-phase-sensitive sub-optical-cycle photoemission from plasmonic nanoantennas
Authors: Keathley Phillip D. , Putnam William P. , Hobbs Richard G. , Berggren Karl K. , Kartner Franz X.
Published: April 2019

We study carrier-envelope-phase-sensitive (CEP-sensitive) photoemission from plasmonic nanoantennas excited with laser pulses of varying incident optical intensities. The CEP-sensitive current exhibits antiresonant-like features that we attribute to competing sub-optical-cycle bursts of photoelectrons.
Optical fiber-driven low-energy electron gun for time-resolved streak diffraction
Authors: Lee Chiwon , Gunther H. Kassier , Miller R. J. Dwayne
Published: April 2019

The wave guiding feature of the optical fibre optical fibres is specifically exploited to construct a novel type of electron gun to realize single-shot low-energy electron diffraction experiments with the sub-picosecond resolution for studying irreversible samples.
UV-photochemistry of the biologically relevant thiol group and the disulfide bond: Evolution of early photoproducts from picosecond X-ray absorption spectroscopy at the sulfur K-Edge
Authors: Ochmann Miguel , Hussain Abid , von Ahnen Inga , Cordones Amy A. , Hong Kiryong , Lee Jae Hyuk , Ma Rory , Adamczyk Katrin , Kim Tae Kyu , Schoenlein Robert W. , Vendrell Oriol , Huse Nils
Published: April 2019

We report on the UV-induced photochemistry of the biologically relevant sulfur-containing thiol group and the disulfide bond in solution using picosecond X-ray absorption spectroscopy at the sulfur K-edge. This study provides element-specific insight into the 267-nm induced photo-chemistry of two model compounds, an aromatic thiol and an aliphatic disulfide. Our transient spectra point to two primary and several secondary photoproducts, and our analysis may aid in understanding UV damage in proteins.
UV-light induced vibrational coherences explain Kasha rule violation in frans-azobenzene
Authors: Nenov Artur , Borrego-Varillas Rocio , Oriana Aurelio , Ganzer Lucia , Segatta Francesco , Conti Irene , Manzoni Cristian , Cerullo Giulio , Garavelli Marco
Published: April 2019

Sub-20-fs transient absorption spectroscopy and simulations show that CNN-bendings dominate the sub-ps dynamics of ππ*-excited trans-azobenzene, thereby driving the system to the ground state through a non-productive decay channel in violation of the Kasha rule.
Direct observation of photoionization dynamics in solution phase induced by femtosecond two-photon excitation
Authors: Koga Masafumi , Yoneda Yusuke , Sotome Hikaru , Miyasaka Hiroshi
Published: April 2019

In solution phase, the solute can be photo-ionized in the lower excitation energy than its ionization potential in gas phase. Therefore, the specific interaction is expected to be exist between the surrounding media and higher excited (Sn) state of the solute. In order to elucidate such polarization effect of solvent on the photoionization process, femtosecond double-pulse excitation was applied to direct detection of low-energy photoionization dynamics of a phenylenediamine derivative in solution phase. From the results of the transient absorption change, in polar solvent, it is clearly indicated that photoionization does not proceed directly from the Sn state, but through specific intermediate state. Moreover,
Excited state vibrational coherence in a binuclear metal adduct: wave packet phase dependant molecular fragmentation under variation of ligand size
Authors: Kruppa Sebastian Volker , Bäppler Florian , Holzer Christof , Dietrich Fabian , Diller Rolf , Klopper Wim , Riehn Christoph
Published: April 2019

Ultrafast vibrational coherence with metal-metal stretching mode character is observed for phosphine-bridged d10-d10 complexes of different size, containing the binuclear [Ag2Cl]+ chromophore in an ion trap. Fragmentation pathways are governed by the wave packet's phase.
Femtosecond infrared pump – stimulated Raman probe spectroscopy: the method and its first application to study vibrational relaxation pathway in liquid water
Authors: Pastorczak Marcin , Nejbauer Michal , Kardas Tomasz , Radzewicz Czesiaw
Published: April 2019

We apply femtosecond-infrared pump- stimulated Raman probe spectroscopy (fs-IR-SRS) which provides sub-100 fs time resolution, spectral resolution better than 10 cm-1 and the 100 cm-1 to 4000 cm-1 probe bandwidth to study vibrational relaxation pathway after vibrational excitation of OH stretching mode in HDO in the system composed of 30 % of HDO in D2O.
Vibrational coherence in ultrafast electron transfer reaction observed by broadband transient absorption spectroscopy
Authors: Yoneda Yusuke , Kudisch Bryan , Rafiq Shahnawaz , Maiuri Margherita , Scholes Gregory , Miyasaka Hiroshi
Published: April 2019

Photoinduced electron transfer (ET) is one of the most important processes in light energy conversion systems. Marcus theory is one of the most famous frameworks on ET reaction in condensed phase. In this theory, reorganization of surrounding media is regarded as a main reaction coordinate. However, ultrafast ET beyond Marcus’ framework has been reported in various systems. To elucidate the role of molecular vibration in ultrafast ET, we have investigated the ET dynamics between a naphthacene dye and aniline derivatives by means of broadband transient absorption spectroscopy. Coherent wavepacket motions of naphthacene dye with frequencies of 300-1600 cm-1 were observed in time domain. The vibrational coherence of 310 cm-1 mode was reduced with increasing electron transfer rate, suggesting this vibration is coupled to electron transfer reaction.
Intersystem crossing in thiobases proceeds by a dark intermediate state
Authors: Teles-Ferreira Danielle Cristina , Borrego-Varillas Rocio , Ganzer Lucia , Nogueira Faria Barbara Elza , Manzoni Cristian , De Silvestri Sandro , Nenov Artur , Conti Irene , Garavelli Marco , Cerullo Giulio , de Paula Ana Maria
Published: April 2019

4-thiouracil (4TU) is studied by transient absorption spectroscopy employing sub-20 fs UV-pulses and hybrid QM(CASPT2) / MM(AMBER) computations (static and dynamic), evidencing that, along the photoexcited relaxation pathway, intersystem crossing originates from a dark intermediate state.
To grow or not to grow: Thermomagnetic behavior of the strong coupling
Authors: Ayala Alejandro , Dominguez C. A. , Hernandez-Ortiz Saul , Hernandez L. A. , Loewe M. , Manreza Paret D. , Zamora R.
Published: April 2019

The properties of strongly interacting matter at finite temperature in a magnetized medium have received a great deal of attention in recent years, mainly due to the so called Inverse Magnetic Catalysis phenomenon whereby the pseudo critical quiral phase transition temperature and the quark condensate above this transition temperature decrease as a function of the magnetic field intensity. In this work we argue that this phenomenon is linked to the properties of the strong coupling when its temperature and magnetic field dependence are considered.
Discovery of the Odderon by TOTEM experiments and the FMO approach
Authors: Martynov Evgenij , Nicolescu Basarab
Published: April 2019

This paper is an extended version of the talk by B. Nicolescu at the XLVIII International Symposium on Multiparticle Dynamics (ISMD2018) at Singapore, 3-7 September, 2018. Theoretical basis and history of the Froissaron and Maximal Odderon (FMO) approach for elastic pp and
$ \bar {p} $
p scattering is presented. Precise formulation of the FMO model at any momentum transfer squared t is given. The model is applied to description and analysis of the experimental data in a wide interval of energy
$ \sqrt s $

and t. The special attention is given for the latest TOTEM data at 13 TeV, both at t = 0 and at t ≠ 0 and to their interpretation in the FMO model. It is emphasized that the last TOTEM results can be considered as clear evidence for the first experimental observation of the Odderon, predicted theoretically about 50 years ago.
Gravitational lensing in conformal and emergent gravity
Authors: Lim Yen-Kheng , Wang Qing-hai
Published: April 2019

The gravitational bending of light in the framework of conformal gravity is considered where an exact solution for null geodesics in the Mannheim-Kazanas is obtained. The linear coeﬃcient γ characteristic to conformal gravity is shown to contribute enhanced deflection compared to the angle predicted by General Relativity for small γ. We also briefly consider gravitational lensing in covariant emergent gravity.
Characterization of the ageing of an epoxy resin using high temperature nanoindentation
Authors: Passilly Bruno , Delannoy Romain
Published: April 2019

This article aims to understand better the mechanical properties and behavior of organic matrix composite materials under elevated temperature conditions. Two specific specimens of cured RTM6 epoxy resin are tested with DMA analysis: one being unaged and the other one aged for 5000 h at 130 °C under ambient air. Anti-plasticization effects seem to occur on aged resin. Series of nano-indentation tests are carried out from the surface to the core of the sample so as to measure gradient properties of the resin, at temperatures up to 150 °C using a high temperature indentation machine prototype. Thermo-oxidation phenomena involve oxidized layer formation during thermal ageing of the epoxy resin which is characterized through measurements of indentation Young’s modulus. After aged treatment, the variation of Young’s modulus of the oxidized layer at the surface of the sample is not clearly affected by the increasing test temperature whereas Young’s modulus of the core of the sample is decreasing significantly with the temperature test as on unaged epoxy resin. Thus, asymptotic growing of the oxidized layer is then confirmed.
Sunflower (Helianthus annuus L.) genetic resources, production and researches in Turkey
Authors: Tan Ahmet Semsettin , Kaya Yalcin
Published: April 2019

Sunflower is one of the leading oilseed crops and it is widely grown in the Thrace region of Turkey. In 2017, in Turkey as a whole, oilseed and confectionary sunflowers were grown on 779.622 ha with a total production of 1 964 385 t of seed, and average yields of 2.64 t ha−1 for oilseed and 1.67 t ha−1 for confectionary types. Turkey is one of the important countries for crop diversity and has been described as a microcenter for some crops, which originated in different parts of the world. Landraces of sunflower (Helianthus annuus L.) show significant diversity in Turkey and have been collected in the framework of the “National Industrial Plant Genetic Resources Project” (NPGRP). Nine hundred and thirty two oilseed and confectionary sunflower accessions are in longterm conservation in the National Seed Gene Bank of Turkey. The mission of the National Sunflower Research Project is to develop improved germplasm and hybrid varieties by conventional and biotechnical breeding techniques in Turkey. New germplasm and breeding lines have been developed to improve oilseed and confectionary sunflower hybrids with desired characters including high yield and oil quality, resistance to diseases such as: Plasmopara halstedii (Farl.) Berl de Toni., Puccinia helianthi Schw., and Orobanche cumana Walr. Adverse conditions are also taken under consideration. These studies are integrated with agronomic and other related research.
L’acide aminométhylphosphonique (AMPA) dans les eaux naturelles et les filières de traitement : origines, comportement et devenir
Authors: Piel S. , Grandcoin A. , Baurès E.
Published: April 2019

L’acide aminométhylphosphonique (AMPA) est le sous-produit de dégradation très répandu du glyphosate et des aminopolyphosphonates (phosphonates). L’utilisation massive de ces molécules conduit à l’omniprésence de l’AMPA dans l’environnement, et en particulier dans les eaux. L’objectif de cette revue de littérature est de résumer et de discuter les connaissances actuelles sur la formation, le transport, la persistance et la toxicité de l’AMPA dans l’environnement. Dans les sols agricoles, l’AMPA est concentré dans la couche arable et se dégrade lentement dans la plupart des sols. Il peut atteindre les eaux souterraines peu profondes, mais il est rarement retrouvé dans les eaux souterraines profondes. L’AMPA fortement adsorbé sur les particules des sols se retrouve dans les cours d’eau et les eaux de surface par ruissellement lors des événements pluvieux. Dans les zones urbaines, l’AMPA provient des aminophosphonates et du glyphosate présents dans les eaux usées et/ou les eaux pluviales selon la configuration du réseau (unitaire ou séparatif). Il est fréquemment quantifié dans le milieu récepteur en aval des stations d’épuration. Il peut être biologiquement dégradé dans les sols et les sédiments dans lesquels il a tendance à s’accumuler tandis que sa photodégradation est très limitée dans les eaux. L’AMPA aussi présent en suspension dans l’air et en quantité non négligeable peut être emporté par de fortes précipitations. Ainsi, l’AMPA provient prin - cipalement des lixiviats agricoles et des rejets d’eaux usées urbaines. La contribution domestique de l’AMPA via le glyphosate est négligeable alors que la contribution via les phosphonates reste peu renseignée. Enfin, il y a un manque critique de données épidémiologiques – en particulier sur l’exposition via l’eau – pour comprendre les effets toxicologiques de l’AMPA sur la santé humaine. Notons cependant que les stations de traitement d’eau potable permettent un abattement significatif de l’AMPA et cela même s’il n’existe pas de limite réglementaire spécifique pour les métabolites en général.
Reproductive Health of Women Veterans: A Systematic Review of the Literature from 2008 to 2017
Authors: Katon Jodie , Zephyrin Laurie , Meoli Anne , Hulugalle Avanthi , Bosch Jeane , Callegari Lisa , Galvan Ileana , Gray Kristen , Haeger Kristin , Hoffmire Claire , Levis Silvina , Ma Erica , Mccabe Jennifer , Nillni Yael , Pineles Suzanne , Reddy Shivani , Savitz David , Shaw Jonathan , Patton Elizabeth
Published: April 2019

The literature on the reproductive health and healthcare of women Veterans has increased dramatically, though there are important gaps. This article aims to synthesize recent literature on reproductive health and healthcare of women Veterans. We updated a literature search to identify manuscripts published between 2008 and July 1, 2017. We excluded studies that were not original research, only included active-duty women, or had few women Veterans in their sample. Manuscripts were reviewed using a standardized abstraction form. We identified 52 manuscripts. Nearly half (48%) of the new manuscripts addressed contraception and preconception care (n = 15) or pregnancy (n = 10). The pregnancy and family planning literature showed that (1) contraceptive use and unintended pregnancy among women Veterans using VA healthcare is similar to that of the general population; (2) demand for VA maternity care is increasing; and (3) women Veterans using VA maternity care are a high-risk population for adverse pregnancy outcomes. A recurrent finding across topics was that history of lifetime sexual assault and mental health conditions were highly prevalent among women Veterans and associated with a wide variety of adverse reproductive health outcomes across the life course. The literature on women Veterans' reproductive health is rapidly expanding, but remains largely observational. Knowledge gaps persist in the areas of sexually transmitted infections, infertility, and menopause.
Common and Uncommon Variations of Pulmonary Venous Drainage in Patients Undergoing Thoracoscopic Lobectomy
Authors: Amore Dario , Casazza Dino , Imitazione Pasquale , Curcio Carlo
Published: April 2019

Background Variations in pulmonary venous anatomy should not be undermined by thoracic surgeons during procedures which involve the pulmonary veins.

Methods We have identified vascular anomalies in 25 of 346 patients undergoing video-assisted thoracoscopic surgery lobectomy at our Thoracic Surgery Unit, between December 2016 and November 2018.

Results Some vascular anomalies described have not been reported in recent literature and include right V7 draining into the middle lobe pulmonary vein, accessory right V6 behind the bronchus intermedius, two V6 from the apical segment of left lower lobe, two V6 from the apical segment of right lower lobe, and one of them draining into the superior pulmonary vein.

Conclusion Thoracic surgeons should be aware of this type of anomalies because failure in the preoperative or intraoperative identification of the pulmonary venous variations may lead to serious complications.
Management of Buerger's Disease in Endovascular Era
Authors: Ghoneim Baker M. , Karmota Ahmed G. , Abuhadema Ahmed M. , Shaker Ahmed A. , Abdelmawla Hany M. , Nasser Mahmoud M. , Elmahdy Hossam Y. , Mostafa Hesham A. , Khairy Hussein M.
Published: April 2019

This study was aimed to report data on the feasibility, safety, and effectiveness of endovascular procedures in a thromboangiitis obliterans diagnosed patients presenting with critical limb ischemia (CLI). Prospective study conducted on patients affected by Buerger's disease who presented to our center along 2 years. Clinical, radiological, and patient-based outcomes were recorded at 3, 6, and 12 months after the intervention. Total 39 patients were included in the study. Fifteen (38.5%) patients underwent percutaneous transluminal angioplasty, another 15 patients (38.5%) underwent follow-up on medical treatment, there are four other patients (10.3%) underwent surgical bypass, and five (12.8%) patients underwent lumbar sympathectomy. The 12 months' outcome showed 66.7% technical success in endovascular group with 46.7% patency rate (p-value = 0.06), 86.7% limb salvage rate (LSR; p-value < 0.04), and 66.7% clinical improvement (p-value = 0.005). The endovascular management of Buerger's disease is feasible, save, and effective with high rate of LSR and clinical improvement.
Oxygen Saturation and Perfusion Index-Based Enhanced Critical Congenital Heart Disease Screening
Authors: Siefkes Heather , Kair Laura , Tancredi Daniel J. , Vasquez Brian , Garcia Lorena , Bedford-Mu Christa , Lakshminrusimha Satyan
Published: April 2019

Objective To determine if addition of perfusion index (PIx) to oxygen saturation (SpO2) screening improves detection of critical congenital heart disease (CCHD) with systemic outflow obstruction.

Study Design We determined screening thresholds for PIx and applied these to a cohort of newborns with and without congenital heart disease (CHD).

Results A total of 123 normal and 21 CHD newborns (including five with critical systemic outflow obstruction) were enrolled. Four of these five critical systemic obstruction subjects passed SpO2-based screen. Four out of these five subjects failed PIx-based screen. The sensitivity for detection of systemic obstruction CCHD when compared with healthy infants increased from 20% (95% confidence interval [CI]: 1–72%) with SpO2 screening alone to 80% (95% CI: 28–100%) with combined SpO2-PIx screen. However, 2.44% of normal infants failed PIx screen.

Conclusion Addition of PIx to SpO2 screening may detect additional cases of CCHD and further research is necessary to come up with optimal screening thresholds.
Outcome of a Modified Perceval Implantation Technique
Authors: Zhigalov Konstantin , Mashhour Ahmed , Mkalaluh Sabreen , Szczechowicz Marcin , Easo Jerry , Eichstaedt Harald C. , Weymann Alexander
Published: April 2019

Background In our institution, we developed a modification of the standard implantation technique of the Perceval sutureless aortic prosthesis (LivaNova, London, United Kingdom) that involves the usage of snuggers for the guiding sutures during valve deployment. The technique has been described elsewhere. In this article, we present the results of our initial case series comprising 128 consecutive patients.

Methods From September 2016 to June 2018, 128 patients received a sutureless Perceval prosthesis (mean age 72.2 ± 8.5 years, 66 males). The data of the patients were prospectively collected in our general database and retrospectively analyzed using the SPSS software version 25 (IBM SPSS Inc., Chicago, Illinois, United States). Primary end points were primary implantation success and 30-day mortality. All patients underwent transthoracic echocardiography on discharge.

Results Our cohort consisted of real-world scenario patients with infective endocarditis, bicuspid aortic valves and one patient with left ventricular assist device. However, we had 100% primary implantation success with no need for valve explantation or paravalvular leaks. All-cause 30-day mortality was 2.3% (3 patients) with no cardiac deaths. Two patients (1.6%) had a permanent neurological deficit, three patients (2.3%) had new-onset renal dialysis, and four patients (3.1%) needed a permanent pacemaker postoperatively.

Conclusion To our knowledge, this is the first case series to report on a modified implantation technique of the Perceval prosthesis. The Perceval valve prosthesis produces excellent outcome in most pathologies, so that current contraindications should be revised.
Labordiagnostik bei Diabetes mellitus
Authors: Hörber Sebastian , Schleicher Erwin , Peter Andreas
Published: April 2019

Laboratory parameters are essential for diagnosis, prognosis and therapy control of diabetes mellitus. Diabetes-specific parameters including glucose, glycated hemoglobin (HbA1c), C-peptide and autoantibodies against beta cell epitopes as well as parameters of lipid metabolism and renal function should be taken into account. The precise and reliable determination of these parameters in accordance with the guidelines of the German Federal Medical Council for the determination of laboratory diagnostics is fundamental for the correct classification and evaluation of the measurement results. For this, important pre-analytical and analytical limitations must be considered.
Develop a home-used EMG sensor system to identify pathological gait with less data via frequency analysis
Authors: Wang Ping , Wang Yabo , Ru Feng
Published: April 2019

In order to develop a low-cost wearable electromyography (EMG) sensor system that can be used at home, compacting the data size is studied first to extract potential features via frequency analysis. A low-cost wearable home-use EMG sensor is then developed. Results show the frequency band at 40-60 Hz of tibialis anterior offers significant differences to identify walking problems (p-value < 0.05), which can be used as a detection standard with a smaller data size. More significantly, data sizes are dramatically reduced by 95.06% compared to the original data size. This finding suggests a potential examining method for identifying pathological gait with the compacted data in satisfactory processing time that can be used at home.
Induced quantum dot probe for material characterization
Authors: Shim Yun-Pil , Ruskov Rusko , Hurst Hilary M. , Tahan Charles
Published: April 2019

We propose a non-destructive means of characterizing a semiconductor wafer via measuring the parameters of an induced quantum dot on the material system of interest with a separate probe chip that can also house the measurement circuitry. We show that a single wire can create the dot, determine if an electron is present, and be used to measure critical device parameters. Adding more wires enables more complicated (potentially multi-dot) systems and measurements. As one application for this concept, we consider a silicon metal-oxide-semiconductor and silicon/silicon-germanium quantum dot qubits relevant to quantum computing and show how to measure low-lying excited states (so-called “valley” states). This approach provides an alternative method for the characterization of parameters that are critical for various semiconductor-based quantum dot devices without fabricating such devices.
Anomalous terahertz dielectric phase in charge-ordered La1/3Sr2/3FeO3 thin film
Authors: K Santhosh Kumar , Rana D. S.
Published: April 2019

Orthoferrites are the model systems for understanding the origin of complex valance-skipping charge ordering (CO) associated with antiferromagnetic spin ordering as a sequence of Fe+3Fe+3Fe+5Fe+3Fe+3Fe+5 … along the pseudocubic (111) direction. Here, we have investigated the low-energy dynamics of one such system La1/3Sr2/3FeO3 along the (111) crystal orientation using terahertz (THz) time domain spectroscopy. The temperature dependent THz optical constants reveal a purely electronic semiconductor to a charge-ordered Mott insulator transition, which is contrary to the reported metal–insulator transition. Above the transition of ∼180 K, THz conductivity shows a thermally activated charge-carrier hopping type conduction with activation energy 92.7 meV (87.3 meV) when measured in cooling (heating). The dielectric constant also indicates that the charge ordering formation starts at 200 K, which exists down to 20 K. Further analysis shows a reduction in the effective number of carriers by a fraction of about six as temperature decreases from 300 K to the CO transition at 200 K; this depletion of carriers triggers the intersite interactions required for CO. These findings suggest that a high dielectric constant associated with charge order in the THz region could be useful for THz applications in communication.
Numerical simulation of photothermal deflection measurement: Efficiency limits of the quadrant photodetector
Authors: Eskef M. , Jlailaty Y. , Alnama K.
Published: April 2019

Significant discrepancies are observed between the values of thermal conductivity and thermal diffusivity obtained from amplitude data and the corresponding values obtained from phase data in one and the same photothermal deflection measurement. Detailed investigation by means of numerical simulation, invoking the probe beam deflection as well as the signal generation in the detector, revealed that the quadrant detector suffers from a lack of efficiency with regard to measuring the deflection amplitude under the condition of relatively strong deflection. As a consequence, the measured amplitude significantly underestimates the actual deflection amplitude in the region of low excitation frequencies. It is demonstrated that this nonlinear behavior of the quadrant detector, never reported before, may lead to large systematic errors in the values for thermal conductivity and thermal diffusivity obtained by means of multiparameter fitting of the amplitude vs square root frequency curve. The origin of this detector inefficiency is discussed on the basis of comparing the time-resolved detector signal with the theoretically calculated deflection. It is found that phase data are much less affected by the reported detector inefficiency and can, therefore, be considered more reliable than the amplitude data. It is concluded that special care should be taken not to rely on the amplitude data unless compatibility with the corresponding phase data has been extensively proved.
Inter-valley phonon-assisted Auger recombination in InGaAs/InP quantum well
Authors: Tito Patricio M. A. , LaPierre R. R. , Pusep Yu. A.
Published: April 2019

Nonradiative processes are studied in InGaAs/InP quantum wells (QWs) as a function of the pump power and the temperature, using time-resolved photoluminescence. Intravalley disorder induced direct and intervalley phonon-assisted indirect Auger processes are found to be responsible for nonradiative recombination in low mobility and high mobility quantum wells, respectively. Both Auger processes are spatially separated: the phonon-assisted and direct Auger recombinations take place in the central part of the QW and near the interfaces, respectively. The recombination rate corresponding to the phonon-assisted Auger process is shown to increase with the temperature, while no influence of the temperature was detected for the rate of the disorder induced direct Auger process. The presented data point to the X and/or L valleys as final states for the Auger electron in the intervalley Auger process. Moreover, Auger recombination associated with different confined levels is studied. We show that the conditions for the intervalley phonon-assisted Auger processes are fulfilled for the ground states of the confined electrons and holes, while the nonradiative recombination due to the excited states is dominated by the direct Auger process.
Detachment of microparticles from electrode erosion and the subsequent breakdown
Authors: Zhong Wei , Zhang Guoliang , Xu Ao
Published: April 2019

Resulted from electrode erosion, microparticles is common and inevitable in gas switches. Once these microparticles acquire field-induced charge and flee into the gap, there micro-discharge, impact damage and field distortion may occur, which eventually cause undesirable electrical breakdown. This paper firstly introduces the detachment criteria of microparticles based on contact pressure, and discusses the microparticles’ detachment criteria under vibration. Results indicate that the larger microparticle could be detached more easily and the detachment criteria is strongly influenced by vibration and working coefficients. Then combined with previous experimental results, how breakdown is induced by the detached microparticles is discussed based on field electron emission. Results indicate that when suffering strong vibration, these charged microparticles could get detached from the electrode surface, act as the field emission source and finally ignite the undesirable electrical breakdown of switches.
Radiative sky cooling: Fundamental principles, materials, and applications
Authors: Zhao Dongliang , Aili Ablimit , Zhai Yao , Xu Shaoyu , Tan Gang , Yin Xiaobo , Yang Ronggui
Published: April 2019

Radiative sky cooling cools an object on the earth by emitting thermal infrared radiation to the cold universe through the atmospheric window (8–13 μm). It consumes no electricity and has great potential to be explored for cooling of buildings, vehicles, solar cells, and even thermal power plants. Radiative sky cooling has been explored in the past few decades but limited to nighttime use only. Very recently, owing to the progress in nanophotonics and metamaterials, daytime radiative sky cooling to achieve subambient temperatures under direct sunlight has been experimentally demonstrated. More excitingly, the manufacturing of the daytime radiative sky cooling material by the roll-to-roll process makes large-scale deployment of the technology possible. This work reviews the fundamental principles of radiative sky cooling as well as the recent advances, from both materials and systems point of view. Potential applications in different scenarios are reviewed with special attention to technology viability and benefits. As the energy situation and environmental issues become more and more severe in the 21st century, radiative sky cooling can be explored for energy saving in buildings and vehicles, mitigating the urban heat island effect, resolving water and environmental issues, achieving more efficient power generation, and even fighting against the global warming problem.