bluuebunny/crossref_metadata_2025 huggingface dataset:
Spatial Modeling of Soil Erosion Risk and Its Implication for Conservation Planning: the Case of the Gobele Watershed, East Hararghe Zone, Ethiopia
Authors: Woldemariam Gezahegn Weldu , Iguala Anteneh Derribew , Tekalign Solomon , Reddy Ramireddy Uttama
Published: February 2018

Soil erosion by water has accelerated over recent decades due to non-sustainable land use practices resulting in substantial land degradation processes. Spatially explicit information on soil erosion is critical for the development and implementation of appropriate Soil and Water Conservation (SWC) measures.The objectives of this study were to estimate the magnitude of soil loss rate, assess the change of erosion risk, and elucidate their implication for SWC planning in the Gobele Watershed, East Hararghe Zone, Ethiopia. Applying remote sensing data, the study first derived the Revised Universal Soil Loss Equation (RUSLE) model parameters in an ArcGIS environment and estimated the soil loss rates. The estimated total soil loss in the watershed was 1,390,130.48 tons in 2000 and 1,022,445.09 tons in 2016 with a mean erosion rate of 51.04 t ha−1 y−1 and 34.26 t ha−1 y−1, respectively. The study area was divided into eight erosion risk classes ranging from very low to extremely high. We established a change detection matrix of the soil erosion risk classes between 2000 and 2016. The change analysis results have revealed that about 70.80% of the soil erosion risk areas remained unchanged, 19.67% increased in total area, and 9.53% decreased, showing an overall worsening of the situation. We identified and mapped areas with a higher and increasing erosion risk as SWC priority areas using a Multi-criteria Decision Rules (MCDR) method. The top three priority levels marked for the emergency SWC measures account for about 0.04%, 0.49%, and 0.83%, respectively. These priority levels are situated along the steep slope areas in the north, northwest, south, and southeast of the Gobele Watershed. It is, thus, very critical to undertake proper intervention measures in upslope areas based on the priority levels to establish sustainable watershed management in the study area.
Research on the Transmission Characteristics of Air-Coupled Ultrasound in Double-Layered Bonded Structures
Authors: Wang Xing-Guo , Wu Wen-Lin , Huang Zhi-Cheng , Chang Jun-Jie , Wu Nan-Xing
Published: February 2018

The ultrasonic transmission spectrum in a double-layered bonded structure is related closely to its interfacial stiffness. Consequently, researching the regularity of the transmission spectrum is of significant interest in evaluating the integrity of the bonded structure. Based on the spring model and the potential function theory, a theoretical model is developed by the transfer matrix method to predict the transmission spectrum in a double-layered bonded structure. Some shift rules of the transmission peaks are obtained by numerical calculation of this model with different substrates. The results show that the resonant transmission peaks move towards a higher frequency with the increase of the normal interfacial stiffness, and each of them has different movement distances with the increasing interfacial stiffness. Indeed, it is also observed that the movement starting points of these peaks are at the specific frequency at which the thickness of either substrate plate equals an integral multiple of half a wavelength. The results from measuring the bonding specimens, which have different interfacial properties and different substrates in this experiment, are utilized to verify the theoretical analysis. Though the theory of “starting points” is not demonstrated effectively, the shift direction and distance exactly match with the result from the theoretical algorithm.
Tandem Lewis Pair Polymerization and Organocatalytic Ring-Opening Polymerization for Synthesizing Block and Brush Copolymers
Authors: Sun Xing-Yu , Ren Wei-Min , Liu Si-Jie , Jia Yin-Bao , Wang Yi-Ming , Lu Xiao-Bing
Published: February 2018

Lewis pair polymerization is a powerful method for preparing soluble polymers bearing pendant active vinyl groups by directly polymerizing dissymmetric divinyl polar monomers. Herein, we present a strategy for synthesizing block and brush copolymers via tandem Lewis pair polymerization of methacrylates, “thiol-ene” click reaction and organocatalytic ring-opening polymerization of lactide.
Inhibitory Effects of a Variety of Aldehydes on Amaranthus tricolor L. and Echinochloa crus-galli (L.) Beauv.
Authors: Chotsaeng Nawasit , Laosinwattana Chamroon , Charoenying Patchanee
Published: February 2018

Thirty-seven commercial aldehydes containing aliphatic chains and aromatic rings as well as heteroaromatic rings were evaluated for their inhibitory activities against Chinese amaranth (Amaranthus tricolor L.) and barnyardgrass (Echinochloa crus-galli (L.) Beauv). Polysorbate 80 (Tween® 80) was used as a surfactant and the research was preliminarily conducted at 400 μM of all aldehydes. Among these aldehydes, (E)-cinnamaldehyde (7) showed the greatest inhibitory effect on seed germination, shoot and root growth of Chinese amaranth by 54.55%, 75.53%, and 85.13% respectively. Similarly, (E)-crotonaldehyde (5), a related α,β-unsaturated aldehyde, inhibited the germination and seedling growth of the tested species at a high percentage. Apart from these two unsaturated aldehydes, no other aliphatic aldehydes had a harmful effect on Chinese amaranth. In terms of benzaldehyde (6), it had no effect on the tested plant; however, many of its derivatives displayed some inhibitory activity. Furthermore, for the ten common heteroaromatic aldehydes, picolinaldehyde (32) had a high inhibitory effect on Chinese amaranth which closely related to the effect of (E)-crotonaldehyde (5) and (E)-cinnamaldehyde (7), whereas, other heteroaromatic aldehydes showed lower effects. In the case of a monocot plant, barnyardgrass, no tested aldehydes reduced seed germination, however, (E)-cinnamaldehyde (7), 2,4,6-trimethoxybenzaldehyde (16) and 4-(dimethylamino)benzaldehyde (24) could inhibit the seedling growth of the plant with low to moderate levels. The herbicidal effects of the most active aldehydes were then further investigated in order to find the minimum concentration of these aldehydes suppressing the germination and growth of the tested plants. At concentrations as low as 50–100 μM some aldehydes could inhibit the seedling growth of the tested species. The structure-activity relationship (SAR) study reported here demonstrates the chemical clues governing the inhibitory activity of aldehydes which could be utilized in the development of highly effective herbicides in the near future.
Retrieval of Hyperspectral Surface Reflectance Based on Machine Learning
Authors: Zhu Sijie , Lei Bin , Wu Yirong
Published: February 2018

Many methods based on radiative-transfer models and empirical approaches with prior knowledge have been developed for the retrieval of hyperspectral surface reflectance. In this paper, we propose a novel approach for atmospheric correction of hyperspectral images based on machine learning. A support vector machine (SVM) is used for learning to predict the surface reflectance from the preprocessed at-sensor radiance image. The preprocessed spectra of each pixel are considered as the spectral feature and hypercolumn based on convolutional neural networks (CNNs) is utilized for spatial feature extraction. After training, the surface reflectance of images from totally different spatial positions and atmospheric conditions can be quickly predicted with the at-sensor radiance image and the models trained before, and no additional metadata is required. On an AVIRIS hyperspectral data set, the performances of our method, based on spectral and spatial features, respectively, are compared. Furthermore, our method outperforms QUAC, and the retrieved spectra have good agreement with FLAASH and AVIRIS reflectance products.
Deciphering the Spectrum of Mitochondrial DNA Mutations in Hepatocellular Carcinoma Using High-Throughput Sequencing
Authors: Yu Chang , Wang Xuefeng , Huang Lifeng , Tong Ying , Chen Lili , Wu Hailong , Xia Qiang , Kong Xiaoni
Published: February 2018

Accumulation of mitochondrial DNA (mtDNA) mutations has been proposed to contribute to the initiation and progression of tumors. By using high-throughput sequencing strategies, we measured 33 specimens including 11 hepatocellular carcinoma (HCC) tissues, 11 corresponding adjacent tissues,
and 11 normal liver tissues. We identified 194 single nucleotide variants (SNVs; including insert and deletion) in 33 liver tissues, and 13 somatic novel mutations were detected, including 7 mutations in the coding region. One of the seven somatic mutations (T7609C, 91.09%) is synonymous,
which does not change amino acid coding; the other four somatic mutations (T6115C, 65.74%; G8387A, 12.23%; G13121A, 93.08%; and T14180C, 28.22%) could result in amino acid substitutions, potentially leading to mitochondrial dysfunction. Furthermore, two mutations in tRNA might influence amino
acid transportation. Consistent with a previous study, we also found that mtDNA copy number was significantly reduced in HCC tissues. Therefore, we established a mitochondrial genome depletion cell line ρ0 and revealed that mtDNA loss reduced proliferation and migration in HCC cells but
promoted their resistance to 5-fluorouracil. Our results suggested that somatic mtDNA mutations may cause mitochondrial dysfunction and affect chemoresistance of HCC cells. These new identified somatic mutations may serve as a reference for future studies of cancer mitochondrial genomes.
Perovskite-structured CaTiO3 coupled with g-C3N4 as a heterojunction photocatalyst for organic pollutant degradation
Authors: Kumar Ashish , Schuerings Christian , Kumar Suneel , Kumar Ajay , Krishnan Venkata
Published: February 2018

A novel graphitic carbon nitride (g-C3N4)–CaTiO3 (CTCN) organic–inorganic heterojunction photocatalyst was synthesized by a facile mixing method, resulting in the deposition of CaTiO3 (CT) nanoflakes onto the surface of g-C3N4 nanosheets. The photocatalytic activity of the as-synthesized heterojunction (along with the controls) was evaluated by studying the degradation of an aqueous solution of rhodamine B (RhB) under UV, visible and natural sunlight irradiation. The CTCN heterojunction with 1:1 ratio of g-C3N4/CT showed the highest photocatalytic activity under sunlight irradiation and was also demonstrated to be effective for the degradation of a colorless, non-photosensitizing pollutant, bisphenol A (BPA). The superior photocatalytic performance of the CTCN heterojunction could be attributed to the appropriate band positions, close interfacial contact between the constituents and extended light absorption (both UV and visible region), all of which greatly facilitate the transfer of photogenerated charges across the heterojunction and inhibit their fast recombination. In addition, the two-dimensional (2D) morphology of g-C3N4nanosheets and CT nanoflakes provides enough reaction sites due to their larger surface area and enhances the overall photocatalytic activity. Furthermore, the active species trapping experiments validate the major role played by superoxide radicals (O2−•) in the degradation of pollutants. Based on scavenger studies and theoretically calculated band positions, a plausible mechanism for the photocatalytic degradation of pollutants has been proposed and discussed.
Modeling H2O and CO2 in Optically Thick Comets Using Asymmetric Spherical Coupled Escape Probability and Application to Comet C/2009 P1 Garradd Observations of CO, H2O, and CO2
Authors: Gersch Alan M. , Feaga Lori M. , A’Hearn Michael F.
Published: February 2018

We have adapted Coupled Escape Probability, a new exact method of solving radiative transfer problems, for use in asymmetrical spherical situations for use in modeling optically thick cometary comae. Here we present the extension of our model and corresponding results for two additional primary volatile species of interest, H2O and CO2, in purely theoretical comets. We also present detailed modeling and results for the specific examples of CO, H2O, and CO2 observations of C/2009 P1 Garradd by the Deep Impact flyby spacecraft.
Finding Transitions of Physical Condition in Jets from Observations over the Range of 103–109 Schwarzschild Radii in Radio Galaxy NGC 4261
Authors: Nakahara Satomi , Doi Akihiro , Murata Yasuhiro , Hada Kazuhiro , Nakamura Masanori , Asada Keiichi
Published: February 2018

We report new measurements of jet width and radiation profiles along jets over the range of 103–109 Schwarzschild radius (R
S) in the nearby radio galaxy NGC 4261 using multifrequency Very Long Baseline Array (VLBA) and Very Large Array images. In the VLBA images, we found parabolic-to-conical transition signatures on both the approaching jet and counterjet width profiles at ∼104
R
S from the central engine. A transition in the radiation profile along the approaching jet was also found at ∼104
R
S clearly. Based on the consistency of the transition locations, we conclude that the physical conditions of the NGC 4261 jets change at this distance. Jet flows that change from accelerating to expanding regions were previously found in M87 and NGC 6251 and are presumably present in NGC 4261. Additionally, we found another transition in the radiation profile at ∼3 × 106
R
S in the conical region. NGC 4261 is the first case in which a jet structural transition is suggested in both the approaching and counter jets; this implies that the active galactic nucleus jet collimation process is fundamentally characterized by the global distribution of ambient pressure rather than the local interaction between the jet and the surrounding medium. We discuss the evolution of jet conditions in terms particle acceleration, cooling, dissipation, and jet pressure balance with the surrounding hot gas.
Meterwavelength Single-pulse Polarimetric Emission Survey. IV. The Period Dependence of Component Widths of Pulsars
Authors: Skrzypczak Anna , Basu Rahul , Mitra Dipanjan , Melikidze George I. , Maciesiak Krzysztof , Koralewska Olga , Filothodoros Alexandros
Published: February 2018

The core component width in normal pulsars, with periods (P) > 0.1 s, measured at the half-power point at 1 GHz, has a lower boundary line (LBL) that closely follows the P
−0.5 scaling relation. This result is of fundamental importance for understanding the emission process and requires extended studies over a wider frequency range. In this paper we have carried out a detailed study of the profile component widths of 123 normal pulsars observed in the Meterwavelength Single-pulse Polarimetric Emission Survey at 333 and 618 MHz. The components in the pulse profile were separated into core and conal classes. We found that at both frequencies, the core, as well as the conal component widths versus period, had a LBL that followed the P
−0.5 relation with a similar lower boundary. The radio emission in normal pulsars has been observationally shown to arise from a narrow range of heights around a few hundred kilometers above the stellar surface. In the past the P
−0.5 relation has been considered as evidence for emission arising from last open dipolar magnetic field lines. We show that the P
−0.5 dependence only holds if the trailing and leading half-power points of the component are associated with the last open field line. In such a scenario we do not find any physical motivation that can explain the P
−0.5 dependence for both core and conal components as evidence for dipolar geometry in normal pulsars. We believe the period dependence is a result of a currently unexplained physical phenomenon.
Identification of the Infrared Counterpart of SGR 1935+2154 with the Hubble Space Telescope
Authors: Levan Andrew , Kouveliotou Chryssa , Fruchter Andrew
Published: February 2018

We present deep Hubble Space Telescope observations of a new magnetar source, the soft gamma-repeater SGR 1935+2154, discovered by Swift. We obtained three epochs of observations: while the source was active in 2015 March, during a quiescent period in 2015 August, and during a further active phase in 2016 May. Close to the center of the X-ray error region identified by Chandra, we find a faint (F140W(AB) = 25.3) source, which fades by a factor of ∼2 over the course of 5 months between the first two epochs of observations, before rebrightening during the second active period. If this source is indeed the counterpart to SGR 1935+2154, then it is among the faintest yet located for a magnetar. Our observations are spaced over 1.3 years and enable us to place limits on the source velocity of μ = (60 ± 40) km s−1 kpc−1; observations on timescales of a decade can hence probe proper motion limits smaller than the velocities observed for the majority of pulsars. The comparison of the optical/IR and X-ray light curves of the source suggests that emission in the two regimes is associated but not directly correlated, offering support for a magnetospheric versus a fallback disk origin.
Wolf 1130: A Nearby Triple System Containing a Cool, Ultramassive White Dwarf
Authors: Mace Gregory N. , Mann Andrew W. , Skiff Brian A. , Sneden Christopher , Kirkpatrick J. Davy , Schneider Adam C. , Kidder Benjamin , Gosnell Natalie M. , Kim Hwihyun , Mulligan Brian W. , Prato L. , Jaffe Daniel
Published: February 2018

Following the discovery of the T8 subdwarf WISE J200520.38+542433.9 (Wolf 1130C), which has a proper motion in common with a binary (Wolf 1130AB) consisting of an M subdwarf and a white dwarf, we set out to learn more about the old binary in the system. We find that the A and B components of Wolf 1130 are tidally locked, which is revealed by the coherence of more than a year of V-band photometry phase-folded to the derived orbital period of 0.4967 days. Forty new high-resolution, near-infrared spectra obtained with the Immersion Grating Infrared Spectrometer provide radial velocities and a projected rotational velocity (v sin i) of 14.7 ± 0.7

for the M subdwarf. In tandem with a Gaia parallax-derived radius and verified tidal locking, we calculate an inclination of i = 29° ± 2°. From the single-lined orbital solution and the inclination we derive an absolute mass for the unseen primary (

M
⊙). Its non-detection between 0.2 and 2.5 μm implies that it is an old (>3.7 Gyr) and cool (T
eff < 7000 K) ONe white dwarf. This is the first ultramassive white dwarf within 25 pc. The evolution of Wolf 1130AB into a cataclysmic variable is inevitable, making it a potential SN Ia progenitor. The formation of a triple system with a primary mass >100 times the tertiary mass and the survival of the system through the common-envelope phase, where ∼80% of the system mass was lost, is remarkable. Our analysis of Wolf 1130 allows us to infer its formation and evolutionary history, which has unique implications for understanding low-mass star and brown dwarf formation around intermediate-mass stars.
The Intricate Structure of HH 508, the Brightest Microjet in the Orion Nebula
Authors: Wu Ya-Lin , Close Laird M. , Kim Jinyoung Serena , Males Jared R. , Morzinski Katie M.
Published: February 2018

We present Magellan adaptive optics Hα imaging of HH 508, which has the highest surface brightness among protostellar jets in the Orion Nebula. We find that HH 508 actually has a shorter component to the west, and a longer and knotty component to the east. The east component has a kink at 0.″3 from the jet-driving star θ
1 Ori B2, so it may have been deflected by the wind/radiation from the nearby θ
1 Ori B1B5. The origin of both components is unclear, but if each of them is a separate jet, then θ
1 Ori B2 may be a tight binary. Alternatively, HH 508 may be a slow-moving outflow, and each component represents an illuminated cavity wall. The ionization front surrounding θ
1 Ori B2B3 does not directly face θ
1 Ori B1B5, suggesting that the EUV radiation from θ
1 Ori C plays a dominant role in affecting the morphology of proplyds even in the vicinity of θ
1 Ori B1B5. Finally, we report an Hα blob that might be ejected by the binary proplyd LV 1.
Extreme Variability Quasars from the Sloan Digital Sky Survey and the Dark Energy Survey
Authors: Rumbaugh N. , Shen Yue , Morganson Eric , Liu Xin , Banerji M. , McMahon R. G. , Abdalla F. B. , Benoit-Lévy A. , Bertin E. , Brooks D. , Buckley-Geer E. , Capozzi D. , Carnero Rosell A. , Carrasco Kind M. , Carretero J. , Cunha C. E. , D’Andrea C. B. , da Costa L. N. , DePoy D. L. , Desai S. , Doel P. , Frieman J. , García-Bellido J. , Gruen D. , Gruendl R. A. , Gschwend J. , Gutierrez G. , Honscheid K. , James D. J. , Kuehn K. , Kuhlmann S. , Kuropatkin N. , Lima M. , Maia M. A. G. , Marshall J. L. , Martini P. , Menanteau F. , Plazas A. A. , Reil K. , Roodman A. , Sanchez E. , Scarpine V. , Schindler R. , Schubnell M. , Sheldon E. , Smith M. , Soares-Santos M. , Sobreira F. , Suchyta E. , Swanson M. E. C. , Walker A. R. , Wester W. ,   (DES Collaboration)
Published: February 2018

We perform a systematic search for long-term extreme variability quasars (EVQs) in the overlapping Sloan Digital Sky Survey and 3 Year Dark Energy Survey imaging, which provide light curves spanning more than 15 years. We identified ∼1000 EVQs with a maximum change in g-band magnitude of more than 1 mag over this period, about 10% of all quasars searched. The EVQs have L
bol ∼ 1045–1047 erg s−1 and L/L
Edd ∼ 0.01–1. Accounting for selection effects, we estimate an intrinsic EVQ fraction of ∼30%–50% among all

quasars over a baseline of ∼15 yr. We performed detailed multi-wavelength, spectral, and variability analyses for the EVQs and compared them to their parent quasar sample. We found that EVQs are distinct from a control sample of quasars matched in redshift and optical luminosity: (1) their UV broad emission lines have larger equivalent widths; (2) their Eddington ratios are systematically lower; and (3) they are more variable on all timescales. The intrinsic difference in quasar properties for EVQs suggests that internal processes associated with accretion are the main driver for the observed extreme long-term variability. However, despite their different properties, EVQs seem to be in the tail of a continuous distribution of quasar properties, rather than standing out as a distinct population. We speculate that EVQs are normal quasars accreting at relatively low rates, where the accretion flow is more likely to experience instabilities that drive the changes in flux by a factor of a few on multi-year timescales.
SDSS IV MaNGA: Dependence of Global and Spatially Resolved SFR–M∗ Relations on Galaxy Properties
Authors: Pan Hsi-An , Lin Lihwai , Hsieh Bau-Ching , Sánchez Sebastián F. , Ibarra-Medel Héctor , Boquien Médéric , Lacerna Ivan , Argudo-Fernández Maria , Bizyaev Dmitry , Cano-Díaz Mariana , Drory Niv , Gao Yang , Masters Karen , Pan Kaike , Tabor Martha , Tissera Patricia , Xiao Ting
Published: February 2018

The galaxy integrated Hα star formation rate–stellar mass relation, or SFR(global)–M
*(global) relation, is crucial for understanding star formation history and evolution of galaxies. However, many studies have dealt with SFR using unresolved measurements, which makes it difficult to separate out the contamination from other ionizing sources, such as active galactic nuclei and evolved stars. Using the integral field spectroscopic observations from SDSS-IV MaNGA, we spatially disentangle the contribution from different Hα powering sources for ∼1000 galaxies. We find that, when including regions dominated by all ionizing sources in galaxies, the spatially resolved relation between Hα surface density (ΣHα
(all)) and stellar mass surface density (Σ*(all)) progressively turns over at the high Σ*(all) end for increasing M
*(global) and/or bulge dominance (bulge-to-total light ratio, B/T). This in turn leads to the flattening of the integrated Hα(global)–M
*(global) relation in the literature. By contrast, there is no noticeable flattening in both integrated Hα(H ii)–M
*(H ii) and spatially resolved ΣHα
(H ii)–Σ*(H ii) relations when only regions where star formation dominates the ionization are considered. In other words, the flattening can be attributed to the increasing regions powered by non-star-formation sources, which generally have lower ionizing ability than star formation. An analysis of the fractional contribution of non-star-formation sources to total Hα luminosity of a galaxy suggests a decreasing role of star formation as an ionizing source toward high-mass, high-B/T galaxies and bulge regions. This result indicates that the appearance of the galaxy integrated SFR–M
* relation critically depends on their global properties (M
*(global) and B/T) and relative abundances of various ionizing sources within the galaxies.
A Model for Protostellar Cluster Luminosities and the Impact on the CO–H2 Conversion Factor
Authors: Gaches Brandt A. L. , Offner Stella S. R.
Published: February 2018

We construct a semianalytic model to study the effect of far-ultraviolet (FUV) radiation on gas chemistry from embedded protostars. We use the protostellar luminosity function (PLF) formalism of Offner & McKee to calculate the total, FUV, and ionizing cluster luminosity for various protostellar accretion histories and cluster sizes. We2 compare the model predictions with surveys of Gould Belt star-forming regions and find that the tapered turbulent core model matches best the mean luminosities and the spread in the data. We combine the cluster model with the photodissociation region astrochemistry code, 3d-pdr, to compute the impact of the FUV luminosity from embedded protostars on the CO-to-H2 conversion factor, X
CO, as a function of cluster size, gas mass, and star formation efficiency. We find that X
CO has a weak dependence on the FUV radiation from embedded sources for large clusters owing to high cloud optical depths. In smaller and more efficient clusters the embedded FUV increases X
CO to levels consistent with the average Milky Way values. The internal physical and chemical structures of the cloud are significantly altered, and X
CO depends strongly on the protostellar cluster mass for small efficient clouds.
Are DY Persei Stars Cooler Cousins of R Coronae Borealis Stars?
Authors: Bhowmick Anirban , Pandey Gajendra , Joshi Vishal , Ashok N. M.
Published: February 2018

In this paper we present, for the first time, the study of low resolution H- and K-band spectra of 7 DY Per type and suspect stars, as well as DY Persei itself. We also observed H- and K-band spectra of 3 R Coronae Borealis (RCB) stars, 1 hydrogen-deficient carbon (HdC) star, and 14 cool carbon stars, including normal giants as comparisons. High 12C/13C and low 16O/18O ratios are characteristic features of majority RCBs and HdCs. We have estimated 16O/18O ratios of the program stars from the relative strengths of the 12C16O and 12C18O molecular bands observed in K-band. Our preliminary analysis suggests that a quartet of the DY Per suspects, along with DY Persei itself, seem to show isotopic ratio strength consistent with that of RCB/HdC stars, whereas two of them do not show significant 13C and 18O in their atmospheres. Our analysis provides further indications that DY Per type stars could be related to the RCB/HdC class of stars.
Kronos and Krios: Evidence for Accretion of a Massive, Rocky Planetary System in a Comoving Pair of Solar-type Stars
Authors: Oh Semyeong , Price-Whelan Adrian M. , Brewer John M. , Hogg David W. , Spergel David N. , Myles Justin
Published: February 2018

We report and discuss the discovery of a significant difference in the chemical abundances of a comoving pair of bright solar-type stars, HD 240430 and HD 240429. The two stars have an estimated 3D separation of ≈0.6 pc (≈0.01 pc projected) at a distance of r ≈ 100 pc with nearly identical 3D velocities, as inferred from Gaia TGAS parallaxes and proper motions, and high-precision radial velocity measurements. Stellar parameters determined from high-resolution spectra obtained with the High Resolution Echelle Spectrometer (HIRES) at the Keck Observatory indicate that the two stars are ∼4 Gyr old. The more metal-rich of the two, HD 240430, shows an enhancement of refractory (

K) elements by ≈0.2 dex and a marginal enhancement of (moderately) volatile elements (

K;

,

,

,

, and

). This is the largest metallicity difference found in a wide binary pair to date. Additionally, HD 240430 shows an anomalously high surface lithium abundance (

), higher than its cooler companion by 0.5 dex. The proximity in phase-space and ages between the two stars suggests that they formed together with the same composition, which is at odds with the observed differences in metallicity and abundance patterns. We therefore suggest that the star HD 240430, “Kronos,” accreted

of rocky material after birth, selectively enhancing the refractory elements as well as lithium in its surface and convective envelope.
Evidence for the Magnetic Breakout Model in an Equatorial Coronal-hole Jet
Authors: Kumar Pankaj , Karpen Judith T. , Antiochos Spiro K. , Wyper Peter F. , DeVore C. Richard , DeForest Craig E.
Published: February 2018

Small, impulsive jets commonly occur throughout the solar corona, but are especially visible in coronal holes. Evidence is mounting that jets are part of a continuum of eruptions that extends to much larger coronal mass ejections and eruptive flares. Because coronal-hole jets originate in relatively simple magnetic structures, they offer an ideal testbed for theories of energy buildup and release in the full range of solar eruptions. We analyzed an equatorial coronal-hole jet observed by the Solar Dynamics Observatory (SDO)/AIA on 2014 January 9 in which the magnetic-field structure was consistent with the embedded-bipole topology that we identified and modeled previously as an origin of coronal jets. In addition, this event contained a mini-filament, which led to important insights into the energy storage and release mechanisms. SDO/HMI magnetograms revealed footpoint motions in the primary minority-polarity region at the eruption site, but show negligible flux emergence or cancellation for at least 16 hr before the eruption. Therefore, the free energy powering this jet probably came from magnetic shear concentrated at the polarity inversion line within the embedded bipole. We find that the observed activity sequence and its interpretation closely match the predictions of the breakout jet model, strongly supporting the hypothesis that the breakout model can explain solar eruptions on a wide range of scales.
Characterizing the Variable Dust Permeability of Planet-induced Gaps
Authors: Weber Philipp , Benítez-Llambay Pablo , Gressel Oliver , Krapp Leonardo , Pessah Martin E.
Published: February 2018

Aerodynamic theory predicts that dust grains in protoplanetary disks will drift radially inward on comparatively short timescales. In this context, it has long been known that the presence of a gap opened by a planet can significantly alter the dust dynamics. In this paper, we carry out a systematic study employing long-term numerical simulations aimed at characterizing the critical particle size for retention outside a gap as a function of particle size, as well as various key parameters defining the protoplanetary disk model. To this end, we perform multifluid hydrodynamical simulations in two dimensions, including different dust species, which we treat as pressureless fluids. We initialize the dust outside of the planet’s orbit and study under which conditions dust grains are able to cross the gap carved by the planet. In agreement with previous work, we find that the permeability of the gap depends both on dust dynamical properties and the gas disk structure: while small dust follows the viscously accreting gas through the gap, dust grains approaching a critical size are progressively filtered out. Moreover, we introduce and compute a depletion factor that enables us to quantify the way in which higher viscosity, smaller planet mass, or a more massive disk can shift this critical size to larger values. Our results indicate that gap-opening planets may act to deplete the inner reaches of protoplanetary disks of large dust grains—potentially limiting the accretion of solids onto forming terrestrial planets.
Modulation of Galactic Cosmic Rays in the Inner Heliosphere over Solar Cycles
Authors: Shen Z.-N. , Qin G.
Published: February 2018

The 11- and 22-year modulation of galactic cosmic rays (GCRs) in the inner heliosphere is studied using a numerical model developed by Qin and Shen in 2017. Based on the numerical solutions of Parker’s transport equations, the model incorporates a modified Parker heliospheric magnetic field, a locally static time-delayed heliosphere, and a time-dependent diffusion coefficients model in which an analytical expression of the variation of magnetic turbulence magnitude throughout the inner heliosphere is applied. Furthermore, during solar maximum, the solar magnetic polarity is determined randomly with the possibility of A > 0 decided by the percentage of the solar north polar magnetic field being outward and the solar south polar magnetic field being inward. The computed results are compared at various energies with several GCR observations, e.g., the Interplanetary Monitoring Platform
8 (IMP 8), EPHIN on board the Solar and Heliospheric Observatory (SOHO), Ulysses, and Voyager 1 and 2, and they show good agreement. We show that our model has successfully reproduced the 11- and 22-year modulation cycles.
The Global and Radial Stellar Mass Assembly of Milky Way-sized Galaxies
Authors: Avila-Reese Vladimir , González-Samaniego Alejandro , Colín Pedro , Ibarra-Medel Héctor , Rodríguez-Puebla Aldo
Published: February 2018

We study the global and radial stellar mass assembly of eight zoomed-in Milky Way (MW)-sized galaxies produced in hydrodynamics cosmological simulations. The disk-dominated galaxies (four) show a fast initial stellar mass growth in the innermost parts, driven mostly by in situ star formation (SF), but since z ∼ 2−1, the SF has entered a long-term quenching phase. The outer regions follow this trend but more gently, as they are more external. As a result, the radial stellar mass growth is highly inside-out due to both inside-out structural growth and inside-out SF quenching. The half-mass radius evolves fast; for instance,

(z = 1) < 0.5 

 (z = 0). Two other runs resemble lenticular galaxies. One also shows a pronounced inside-out growth, and the other one presents a nearly uniform radial mass assembly. The other two galaxies suffered late major mergers. Their normalized radial mass growth histories (MGHs) are very close, but with periods of outside-in assembly during or after the mergers. For all of the simulations, the archaeological radial MGHs calculated from the z = 0 stellar particle age distribution are similar to current MGHs, which shows that the mass assembly by ex situ stars and the radial mass transport do not significantly change their radial mass distributions. Our results agree qualitatively with observational inferences from the fossil record method applied to a survey of local galaxies and from look-back observations of progenitors of MW-sized galaxies. However, the inside-out growth mode is more pronounced, and the

growth is faster in simulations than in observational inferences.
The Strong Gravitationally Lensed Herschel Galaxy HLock01: Optical Spectroscopy Reveals a Close Galaxy Merger with Evidence of Inflowing Gas
Authors: Marques-Chaves Rui , Pérez-Fournon Ismael , Gavazzi Raphael , Martínez-Navajas Paloma I. , Riechers Dominik , Rigopoulou Dimitra , Cabrera-Lavers Antonio , Clements David L. , Cooray Asantha , Farrah Duncan , Ivison Rob J. , Jiménez-Ángel Camilo E. , Nayyeri Hooshang , Oliver Seb , Omont Alain , Scott Douglas , Shu Yiping , Wardlow Julie
Published: February 2018

The submillimeter galaxy (SMG) HERMES J105751.1+573027 (hereafter HLock01) at z = 2.9574 ± 0.0001 is one of the brightest gravitationally lensed sources discovered in the Herschel Multi-tiered Extragalactic Survey. Apart from the high flux densities in the far-infrared, it is also extremely bright in the rest-frame ultraviolet (UV), with a total apparent magnitude m
UV ≃ 19.7 mag. We report here deep spectroscopic observations with the Gran Telescopio Canarias of the optically bright lensed images of HLock01. Our results suggest that HLock01 is a merger system composed of the Herschel-selected SMG and an optically bright Lyman break-like galaxy (LBG), separated by only 3.3 kpc in projection. While the SMG appears very massive (M
* ≃ 5 × 1011
M
⊙), with a highly extinguished stellar component (A

V
 ≃ 4.3 ), the LBG is a young, lower-mass (M
* ≃ 1 × 1010
M
⊙), but still luminous (

) satellite galaxy. Detailed analysis of the high signal-to-noise ratio (S/N) rest-frame UV spectrum of the LBG shows complex kinematics of the gas, exhibiting both blueshifted and redshifted absorption components. While the blueshifted component is associated with strong galactic outflows from the massive stars in the LBG, as is common in most star-forming galaxies, the redshifted component may be associated with gas inflow seen along a favorable sightline to the LBG. We also find evidence of an extended gas reservoir around HLock01 at an impact parameter of 110 kpc, through the detection of C ii
λλ1334 absorption in the red wing of a bright Lyα emitter at z ≃ 3.327. The data presented here highlight the power of gravitational lensing in high S/N studies to probe deeply into the physics of high-z star-forming galaxies.
Real world experience with the all-oral interferon free regimen for the treatment of chronic hepatitis c virus infection in the Lebanese population
Authors: Saba Jowana , Abou Rached Antoine , Yaghi Cesar , Sharara Alaa , Ammar Walid
Published: February 2018

Introduction: The treatment of hepatitis C has dramatically improved since the introduction of the new Direct-Acting Antivirals (DAAs). The aim of this study is to assess the effectiveness and safety of all oral DAAs with or without ribavirin in the treatment of hepatitis C virus (HCV) in treatment naïve and experienced Lebanese population.

Methodology: We reviewed all cases approved for hepatitis C treatment with DAAs according to the Lebanese guidelines for treatment of HCV at the Ministry of Public Health from October 2015 till December 2016. Available data concerning age, sex, mode of transmission, genotype (GT) and subtype, fibrosis stage, previous treatment (if present), new DAAs treatment, and sustained virological response at week 12 (SVR12) were collected.

Results: During a period of 15 months (October 2015 to December 2016), 186 patients were treated with DAAs. 57% were male and the mean age was 54.3 years. The source of infection was unknown in 51% of cases and blood transfusion in 35.5% of cases. Genotype 1 was the most predominant genotype (45%), followed by GT4 (34%) and GT3 (12%). 71.6% of patients had advanced fibrosis before starting DAAs and 57% were cirrhotic. 42% of patients were treatment experienced (85% pegylated interferon and ribavirin). Different DAAs regimens were used according to the Lebanese guidelines for treatment of HCV: Ledipasvir/Sofosbuvir (38.7%), Sofosbuvir/Daclatasvir (16.1%), Sofosbuvir/Velpatasvir (1.6%), Sofosbuvir/RBV (7.5%), Ombitasvir/Paritaprevir/Ritonavir (17.5%) and Ombitasvir/Paritaprevir/Ritonavir -Dasabuvir (18.8%). Ribavirin was used in 51.6% of cases. SVR12 was achieved in 93% of patients (relapse in 4%, loss of follow up and/or severe adverse effect in 3%). SVR 12 was achieved in 93%, 96% and 94% of GT1, GT3 and GT4 cases respectively. SVR12 was seen in 91.3% of cirrhotic patients vs. 98.7% of F0-F3 patients. (p = 0.047).  There was no difference in SVR12 between treatment naïve and experienced patients. Hepatocellular carcinoma developed in 5 patients (2.9%) during the study period.

Conclusion: This is the first real world Lebanese data of HCV treatment with DAAs. The study population was significant for a large number of patients with cirrhotic (50%) and treatment experienced patients (42%). SVR12 was achieved in 93% of patients with no difference between treatment naïve and experienced patients. SVR12 was lower in patients with cirrhosis compared to patients with lower stage of fibrosis (91.3% vs. 98.7%).
The The importance of blood culture and serology for Brucellosis diagnosis and treatment
Authors: Faddoul Lama , Azar Rania , Haddad Antoine , Hanna Abi
Published: February 2018

Introduction: Brucellosis is a zoonotic endemic disease in Lebanon. It is caused by direct transmission of Brucella from contaminated animal products to humans. If left untreated brucellosis might lead to several complications and a chronic disease state. The prompt diagnosis of brucellosis has the ability to limit the progression of the disease, especially if the correct treatment is administered for the adequate amount of time. The aim of this study is to determine the optimal diagnostic tool and to assess Brucella burden in Lebanon.

Methodology: This retrospective study was performed by reviewing the medical charts of 46 brucellosis patients from three Lebanese hospitals. Brucellosis diagnostic tests were compared and sensitivity of each test was calculated, as well as, the level of agreement with other standard diagnostic tools. Data retrieved were analyzed for relevance and statistical significance using the statistical package for social sciences version 23.

Results: Sensitivity results of the diagnostic tests were: Rose Bengal test (RBT) 94.7%, blood culture 65.6%, standard agglutination test (SAT) melitensis 95.1% and SAT abortus 97.6%. The level of agreement between RBT and SAT melitensis as well as abortus is 98% and 90.18%, respectively. While the level of agreement between Blood culture and SAT melitensis as well as abortus is 66.88% and 64.5%, respectively.

Discussion: Culture techniques require further optimization in order to find the best diagnostic tool for brucellosis. Meanwhile, Blood Rose Bengal test held a significant potential for identifying Brucella infection in a highly sensitive, cost effective and time saving manner.
The Brucella endocarditis: diagnostic challenges
Authors: Ephrem Christelle Georges , Matar Madonna J , Chalhoub Gaelle C , Greige Wafaa G
Published: February 2018

Introduction: Brucellosis is a multisystemic infectious disease, which can manifest as endocarditis. Diagnosis can be challenging.

Case Presentation: An 80-year-old male patient presented with fever 38.5 °C, cough and progressive shortness of breath of 14 days. History of Brucellosis 18 months earlier inadequately treated. Physical examination showed a mid-frequency mitral and aortic murmur. Brucella serologies and blood cultures were positive. He was discharged on Doxycycline and Rifampicin for 3 months and was lost to follow up. Four months later, he presented for recurrent fever. Physical examination showed a radiating heart murmur. Blood cultures were negative; however, blocking antibodies were 1/2560. Echocardiography showed calcified aortic stenosis. TEE showed an abscess formation at the level of the non-coronary cusp. Ceftriaxone 3g IV q24h, gentamicin 80mg IV q8h, doxycycline 100mg po q12h and trimethoprim-sulfamethoxazole 160/800 mg po q12h were initiated (shortage of rifampicin). Aortic bio-prosthesis was successfully inserted, one week after initiating antibiotics. Intraoperative cultures were negative. He was discharged 18 days following surgery on doxycycline 100 mg po q12h, and rifampicin 900mg po q24h and ciprofloxacin 500mg po q 12h for 3 more months, with twice a month follow up.

Discussion: Endocarditis is one of the most lethal complication of Brucellosis. Early diagnosis and effective medical and surgical management are essential.
Administrer une ferme-modèle au xix e siècle : deux expériences d’agronomes entrepreneurs ruraux, Mathieu de Dombasle et Rieffel
Authors: Joly Nathalie , Bourrigaud René , Knittel Fabien
Published: February 2018

En divers points de l’Europe du Nord et de l’Est, des fermes-modèles se créent à l’aube du xix e siècle, avec l’objectif de favoriser le progrès agricole par l’exemple et l’émulation entre propriétaires. Y sont expérimentés les principes d’une agriculture raisonnée visant les profits les plus élevés à partir de nouveaux procédés de culture et d’élevage. Cet article examine la contribution des fermes-modèles à l’histoire de la gestion de l’entreprise agricole, sur la base de deux établissements avant-gardistes en France : Roville et Grand-Jouan, le premier étant dirigé par une grande figure de l’agronomie, Mathieu de Dombasle, et le second par un ancien élève de l’Institut de Roville, Jules Rieffel. Il met en lumière les pratiques managériales et comptables d’une administration « savante » des domaines agricoles, les schémas de pensée qui l’inspirent et la panoplie d’outils lui servant de boussole. De ces laboratoires de l’agriculture raisonnée émergent de nouvelles disciplines au travail et un esprit de quantification qui participent à la transformation des rapports entre la technique et la gestion, la rationalité des décisions du chef d’entreprise étant désormais considérée comme déterminante dans le succès de l’entreprise agricole.
Ressources génétiques : garantir l’accès à un bien public mondial ou compenser sa marchandisation ?
Authors: Thomas Frédéric
Published: February 2018

Au cours du xx e siècle, les pratiques scientifiques ont lentement fait des ressources génétiques un bien public circulant plus ou moins librement entre les communautés scientifiques et les nations. Le recours récent aux brevets pour protéger les inventions dans le domaine des biotechnologies a considérablement bouleversé ces pratiques, et ces ressources deviennent de plus en plus des biens marchands privés. Il en résulte aujourd’hui des régimes juridiques internationaux et nationaux hésitant entre le libre accès à la ressource favorisant son appropriation privée (sans contrepartie) et l’accès contractualisé générant des compensations à l’appropriation privée. Le présent article étudie la confrontation mais aussi l’hybridation de ces deux philosophies depuis les années 1990, et illustre par ce biais les défis à relever pour construire la gouvernance de ce bien public mondial face à des brevets donnant des droits très exclusifs sur la ressource.
From indenture to entrepreneurship: labour issues in Indonesian palm tree plantations
Authors: Barral Stéphanie
Published: February 2018

L’histoire sociale du capitalisme de plantation indonésien montre le développement de plusieurs formes historiques de capitalisme agraire et d’entrepreneuriat par les ouvriers agricoles des plantations. Les régulations étatiques et l’environnement économique et foncier en sont les deux principaux facteurs explicatifs proposés dans cet article. Pendant la période coloniale, le système de travail forcé était le mode de mise au travail des ouvriers qui bénéficiaient d’une autonomie minimale. Deux décennies de mouvements sociaux, qui suivirent la déclaration d’indépendance du pays en 1945, ont apporté un certain progrès social dans les plantations par la formalisation du droit du travail. Pendant la période suivante, la libéralisation de certaines mesures a modifié le système de fourniture de protections sociales, déplaçant la responsabilité du système de retraite des firmes vers les ouvriers eux-mêmes. Les stratégies d’entrepreneuriat mises en œuvre par ces derniers pour y répondre sont largement dépendantes du contexte économique et foncier dans lequel ils évoluent.