bluuebunny/crossref_metadata_2025 huggingface dataset:
La contabilidad un elemento indispensable en el desarrollo de las empresas
Authors: Morales Espinoza Dina Yolanda , Morales Espinosa Judith  María
Published: April 2019

Este artículo tuvo como objetivo explicar sobre el estudio de la contabilidad como un elemento indispensable en el desarrollo de las empresas, es de conocimiento general que desde tiempos muy remotos las organizaciones han necesitado de la contabilidad para su eficiente desenvolvimiento empresarial. Dentro del alcance de la investigación se estableció un manejo adecuado de la contabilidad con el fin de que les permita a las empresas una correcta toma de decisiones y así asegurar la permanencia de las empresas a largo plazo.

En cuanto a la metodología se utilizó el enfoque de tipo participativa, cualitativa, exploratoria y descriptiva, en donde se manejó el razonamiento para obtener conclusiones que partieron de hechos aceptados como válidos, y así llegar a las conclusiones generales. Para realizar el sondeo de la información se utilizó dos técnicas: la técnica de observación en las empresas privadas y la realización de encuestas a diez directivos representantes de la Cámara de Comercio de la ciudad de Loja.

En los resultados se hizo mención a la información obtenida de los actores involucrados en la investigación, quienes aludieron a la importancia de la contabilidad para el desarrollo de las empresas, pues la consideran un pilar fundamental en la gerencia de las empresas que refleja el fruto de la toma de decisiones de los administradores, así como un excelente referente de información financiera para predecir el futuro de las empresas.

 Finalmente se concluyó que para que una empresa funcione eficientemente es necesario un esfuerzo en conjunto de los directivos y subordinados. Es así, que en las empresas la contabilidad es una herramienta importante e indispensable para su desarrollo, sin embargo, en la actualidad muchos empresarios no reconocen estas ventajas y no le dan importancia que merece a la contabilidad.
MULTIKULTURALISME INDONESIA (STUDI PERBANDINGAN ANTARA KONSEP MADANI NURCHOLISH MADJID DAN KONSEP CIVIL SOCIETY)
Authors: Dewantara Agustinus Wisnu
Published: April 2019

Multiculturalism is difficult to define. As a descriptive term, it has been taken to refer to cultural diversity. As a normative term, multiculturalism implies a positive endorsement, even celebration, of communal diversity, typically based on either the right of different groups to respect and recognize, or to the alleged benefits to the larger society of moral and cultural diversity”. What about Indonesia? In fact, Indonesian cultures indicate the multiculturalism. Is that similar with the concept of “madani”? What about with the concept of the civil society? Which one can adapt in Indonesia? In the cultural environment of Indonesia, cultures are not only interacted or isolated. Those two strategies work at the same time and apply to different aspects of cultures to create new forms of cultures. Multiculturalism can be defined in a ways that go beyond human activities to give a vivid multi-dimensional understanding of cultural interaction, cultural isolation and phenomena between these two extremes
Properties of the Bare Nucleus of Comet 96P/Machholz 1*
Authors: Eisner N. L. , Knight M. M. , Snodgrass C. , Kelley M. S. P. , Fitzsimmons A. , Kokotanekova R.
Published: April 2019

We observed comet 96P/Machholz 1 on a total of nine nights before and after perihelion during its 2017/2018 apparition. Both its unusually small perihelion distance and the observed fragmentation during multiple apparitions make 96P an object of great interest. Our observations show no evidence of a detectable dust coma, implying that we are observing a bare nucleus at distances ranging from 2.3 to 3.8 au. Based on this assumption, we calculated its color and found average values of g′–r′ = 0.50 ± 0.04, r′–i′ = 0.17 ± 0.03, and i′–z′ = 0.06 ± 0.04. These are notably more blue than those of the nuclei of other Jupiter-family and long-period comets. Furthermore, assuming a bare nucleus, we found an equivalent nuclear radius of 3.4 ± 0.2 km with an axial ratio of at least 1.6 ± 0.1. The lightcurve clearly displays one large peak, one broad flat peak, and two distinct troughs, with a clear asymmetry that suggests that the shape of the nucleus deviates from that of a simple triaxial ellipsoid. This asymmetry in the lightcurve allowed us to constrain the nuclear rotation period to 4.10 ± 0.03 hr and 4.096 ± 0.002 hr before and after perihelion, respectively. Within the uncertainties, 96P’s rotation period does not appear to have changed throughout the apparition, and we conclude a maximum possible change in rotation period of 130 s. The observed properties were compared to those of comet 322P and interstellar object 1I/‘Oumuamua in an attempt to study the effects of close perihelion passages on cometary surfaces and their internal structure and the potential interstellar origin of 96P.
An Updated Model for Circumbinary Planets Orbiting the sdB Binary NY Virginis
Authors: Song Shuo , Mai Xinyu , Mutel Robert L. , Pulley David , Faillace George , Watkins Americo
Published: April 2019

We report 18 new primary minima timing observations of the short-period eclipsing binary system NY Virginis. We combined these minima with previously published primary minima to update circumbinary exoplanet models in this system based on O − C timing variations. We performed a nonlinear least-squares minimization search using a quadratic ephemeris and either one or two exoplanets. The only model with an acceptable fit includes a period derivative

and two planets in eccentric orbits e = 0.15, 0.15 with minimum masses of 2.7 and 5.5 Jovian masses. Analysis of the orbit stability shows that this solution is stable for at least 108 years, but a small increase in eccentricity (e ≥ 0.20) for either planet renders the orbits unstable in less than 106 years. A number of model parameters are significantly degenerate, so additional observations are required to determine planetary parameters with high statistical confidence.
Five Gas-rich Ultrafaint Dwarf Galaxy Candidates Discovered in WIYN Imaging of ALFALFA Sources
Authors: Janesh William , Rhode Katherine L. , Salzer John J. , Janowiecki Steven , Adams Elizabeth A. K. , Haynes Martha P. , Giovanelli Riccardo , Cannon John M.
Published: April 2019

We present results from the analysis of WIYN pODI imaging of 23 ultracompact high-velocity clouds (UCHVCs), which were identified in the ALFALFA H i survey as possible dwarf galaxies in or near the Local Group. To search for a resolved stellar population associated with the H i gas in these objects, we carried out a series of steps designed to identify stellar overdensities in our optical images. We identify five objects that are likely stellar counterparts to the UCHVCs, at distances of ∼350 kpc to ∼1.6 Mpc. Two of the counterparts were already described in Janesh et al.; the estimated distance and detection significance for one of them changed in the final analysis of the full pODI data set. At their estimated distances, the detected objects have H i masses from 2 × 104 to 3 × 106
M
⊙, M

V
from −1.4 to −7.1, and stellar masses from 4 × 102 to 4 × 105
M
⊙. None of the objects shows evidence of a young stellar population. Their properties would make the UCHVCs some of the most extreme objects in and around the Local Group, comparable to ultrafaint dwarf galaxies in their stellar populations, but with significant gas content. Such objects probe the extreme end of the galaxy mass function and provide a test bed for theories regarding the baryonic feedback processes that impact star formation and galaxy evolution in this low-mass regime.
Sub-band Image Reconstruction Using Differential Chromatic Refraction
Authors: Lee Matthias A. , Budavári Tamás , Sullivan Ian S. , Connolly Andrew J.
Published: April 2019

Refraction by the atmosphere causes the positions of sources to depend on the airmass through which an observation was taken. This shift is dependent on the underlying spectral energy of the source and the filter or bandpass through which it is observed. Wavelength-dependent refraction within a single passband is often referred to as differential chromatic refraction (DCR). With a new generation of astronomical surveys undertaking repeated observations of the same part of the sky over a range of different airmasses and parallactic angles, DCR should be a detectable and measurable astrometric signal. In this paper we introduce a novel procedure that takes this astrometric signal and uses it to infer the underlying spectral energy distribution of a source; we solve for multiple latent images at specific wavelengths via a generalized deconvolution procedure built on robust statistics. We demonstrate the utility of such an approach for estimating a partially deconvolved image, at higher spectral resolution than the input images, for surveys such as the Large Synoptic Survey Telescope.
Evidence for Super-Alfvénic Oscillations in Solar Type III Radio Burst Sources
Authors: Mohan Atul , Mondal Surajit , Oberoi Divya , Lonsdale Colin J.
Published: April 2019

At the site of their origin, solar meter-wave radio bursts contain pristine information about the local coronal magnetic field and plasma parameters. On its way through the turbulent corona, this radiation gets substantially modified due to propagation effects. Effectively disentangling the intrinsic variations in emission from propagation effects has remained a challenge. We demonstrate a way to achieve this using a snapshot spectroscopic imaging study of weak type III bursts using data from the Murchison Widefield Array. Using this study, we present the first observational evidence for second-scale quasi-periodic oscillations (QPOs) in burst source sizes and orientation with simultaneous QPOs in intensity. The observed oscillations in source sizes are so fast and large that they require two orders of magnitude larger Alfvén  speed than the typical local value of 0.5 Mm s−1 at the burst generation heights, if interpreted within an MHD framework. These observations imply the presence of a quasi-periodic regulation mechanism operating at the particle injection site, modulating the geometry of energetic electron beams that generate type III bursts. In addition, we introduce a method to characterize plasma turbulence in the mid-coronal ranges. We also detect evidence for a systematic drift in the location of the burst sources superposed on the random jitter induced by scattering. We interpret this as the motion of the open flux tube within which the energetic electron beams travel.
Application of Clumpy Torus Model to Broadband X-Ray Spectra of Two Seyfert 1 Galaxies: IC 4329A and NGC 7469
Authors: Ogawa Shoji , Ueda Yoshihiro , Yamada Satoshi , Tanimoto Atsushi , Kawaguchi Toshihiro
Published: April 2019

We apply a new X-ray clumpy torus model, XCLUMPY, in which the clump distribution is assumed to be the same as that in the infrared clumpy torus model (CLUMPY) by Nenkova et al., to the broadband X-ray spectra of type-1 active galactic nuclei (AGNs) for the first time. We analyze the archival data of IC 4329A and NGC 7469 observed with NuSTAR/Suzaku and NuSTAR/XMM-Newton, respectively, whose infrared spectra were studied with CLUMPY by Ichikawa et al. and optical extinctions (A
V) of the tori were estimated. We consider two models, invoking (Model 1) a relativistic reflection component from the accretion disk and (Model 2) a partial absorber. Assuming that the narrow Fe Kα emission line at 6.4 keV originates from the torus, we separate the contribution of the torus reflection components in the total spectra. Our models yield equatorial hydrogen column densities of the tori to be

(0.53–1.43) × 1023 cm−2 and

(0.84–1.43) × 1024 cm−2, for IC 4329A and NGC 7469, respectively. We find that the N
H/A
V ratios in the tori are by factors of 25–68 (IC 4329A) and 2.4–3.9 (NGC 7469) smaller than that in the Galactic interstellar medium (ISM). These results suggest that a non-negligible fraction of AGNs are “dust-rich” compared with the Galactic ISM, as opposite to the general trend previously reported in many obscured AGNs.
Comparison of Gaia DR2 Parallaxes of Stars with VLBI Astrometry
Authors: Xu 徐 Shuangjing 双敬 , Zhang 张 Bo 波 , Reid Mark J. , Zheng 郑 Xingwu 兴武 , Wang 王 Guangli 广利
Published: April 2019

We compare the parallaxes of stars from VLBI astrometry in the literature to those in the Gaia DR2 catalog. Our full sample contains young stellar objects, evolved AGB stars, pulsars, and other radio stars. Excluding AGB stars, which show significant discrepancies between Gaia and VLBI parallaxes, and stars in binary systems, we obtain an average, systematic, parallax offset of −75 ± 29 μas for Gaia DR2, consistent with their estimate of a parallax zero-point between −100 and 0 μas.
MMS Observations of Kinetic-size Magnetic Holes in the Terrestrial Magnetotail Plasma Sheet
Authors: Huang S. Y. , He L. H. , Yuan Z. G. , Sahraoui F. , Contel O. Le , Deng X. H. , Zhou M. , Fu H. S. , Jiang K. , Yu X. D. , Li H. M. , Deng D. , Pollock C. J. , Torbert R. B. , Burch J. L.
Published: April 2019

Kinetic-size magnetic holes (KSMHs) in the terrestrial magnetotail plasma sheet are statistically investigated using the observations from the Magnetospheric Multiscale mission. The scales of KSMHs are found to be smaller than one ion gyroradius or tens of electron gyroradii. The occurrence distributions of KSMHs have dawn–dusk asymmetry (duskside preference) in the magnetotail, which may be caused by the Hall effect. Most events of KSMHs (71.7%) are accompanied by a substorm, implying that substorms may provide favorable conditions for the excitation of KSMHs. However, there is a weak correlation between KSMHs and magnetic reconnection. The statistical results reveal that for most of the events, the electron total temperature and perpendicular temperature increase while the electron parallel temperature decreases inside the KSMHs. The electron temperature anisotropy (T
e⊥/

) is observed in 72% of KSMHs. Whistler-mode waves are frequently observed inside the KSMHs, and most (92%) KSMHs associated with whistler waves have enhancements of electron perpendicular distributions and satisfy the unstable condition of whistler instability. This suggests that the observed electron-scale whistler waves, locally generated by the electron temperature anisotropy, could couple with the electron-scale KSMHs. The observed features of KSMHs and their coupling to electron-scale whistlers are similar to the ones in the turbulent magnetosheath, implying that they are ubiquitous in the space plasmas. The generation of KSMHs in the plasma sheet could be explained by an electron vortex magnetic hole, magnetosonic solitons, and/or ballooning/interchange instabilities.
Four Metal-poor Stars in the Sagittarius Dwarf Spheroidal Galaxy∗
Authors: Chiti Anirudh , Frebel Anna
Published: April 2019

We present the metallicities and carbon abundances of four newly discovered metal-poor stars with −2.2 < [Fe/H] < −1.6 in the Sagittarius dwarf spheroidal galaxy. These stars were selected as metal-poor member candidates using a combination of public photometry from the SkyMapper Southern Sky Survey and proper-motion data from the second data release from the Gaia mission. The SkyMapper filters include a metallicity-sensitive narrowband v filter centered on the Ca ii K line, which we use to identify metal-poor candidates. In tandem, we use proper-motion data to remove metal-poor stars that are not velocity members of the Sagittarius dwarf spheroidal galaxy. We find that these two data sets allow for efficient identification of metal-poor members of the Sagittarius dwarf galaxy to follow up with further spectroscopic study. Two of the stars we present have [Fe/H] < −2.0, which adds to the few other such stars currently identified in the Sagittarius dwarf galaxy that are likely not associated with the globular cluster M54, which resides in the nucleus of the system. Our results confirm that there exists a very metal-poor stellar population in the Sagittarius dwarf galaxy. We find that none of our stars can be classified as carbon-enhanced metal-poor stars. Efficiently identifying members of this population will be helpful to further our understanding of the early chemical evolution of the system.
The Evolution of the He ii-ionizing Background at Redshifts 2.3 < z < 3.8 Inferred from a Statistical Sample of 24 HST/COS He ii Lyα Absorption Spectra*
Authors: Worseck Gábor , Davies Frederick B. , Hennawi Joseph F. , Prochaska J. Xavier
Published: April 2019

We present measurements of the large-scale (≈40 comoving Mpc) effective optical depth of He ii Lyα absorption,

, at 2.54 < z < 3.86 toward 16 He ii-transparent quasars observed with the Cosmic Origins Spectrograph on the Hubble Space Telescope, to characterize the ionization state of helium in the intergalactic medium (IGM). We provide the first statistical sample of

measurements in six signal-to-noise ratio ≳3 He ii sightlines at z > 3.5, and study the redshift evolution and sightline-to-sightline variance of

in 24 He ii sightlines. We confirm an increase of the median

from ≃2 at z = 2.7 to

at z > 3, and a scatter in

that increases with redshift. The z > 3.5 He ii absorption is predominantly saturated, but isolated narrow (Δv < 650 km s−1) transmission spikes indicate patches of reionized helium. We compare our measurements to predictions for a range of UV background models applied to outputs of a large-volume (146 comoving Mpc)3 hydrodynamical simulation by forward-modeling our sample’s quality and size. At z > 2.74, the variance in

significantly exceeds expectations for a spatially uniform UV background, but is consistent with a fluctuating radiation field sourced by variations in the quasar number density and the mean free path in the post-reionization IGM. We develop a method to infer the approximate median He ii photoionization rate

of a fluctuating UV background from the median

, finding a factor ≃5 decrease in

between z ≃ 2.6 and z ≃ 3.1. At z ≃ 3.1,

s−1 corresponds to a median He ii fraction of ≃2.5%, indicating that our data probe the tail end of He ii reionization.
Nonequilibrium Ionization States within Galactic Outflows: Explaining Their O vi and N v Column Densities
Authors: Gray William J. , Scannapieco Evan , Lehnert Matthew D.
Published: April 2019

We present a suite of one-dimensional spherically symmetric hydrodynamic simulations that study the atomic ionization structure of galactic outflows. We track the ionization state of the outflowing gas with a nonequilibrium atomic chemistry network that includes photoionization, photoheating, and ion-by-ion cooling. Each simulation describes a steady-state outflow that is defined by its mass and energy input rates, sonic radius, metallicity, and UV flux from both the host galaxy and metagalactic background. We find that for a large range of parameter choices, the ionization state of the material departs strongly from what it would be in photoionization equilibrium, in conflict with what is commonly assumed in the analysis of observations. In addition, nearly all the models reproduce the low N v to O vi column density ratios and the relatively high O vi column densities that are observed.
Extended Radio Structures and a Compact X-Ray Cool-core in the Cluster Source PKS 1353–341
Authors: Cheung C. C. , Giacintucci Simona , Clarke T. E.
Published: April 2019

We present a radio and X-ray study of PKS 1353–341, the brightest cluster galaxy radio source at the center of a recent Chandra-discovered X-ray cluster. Our multi-frequency Very Large Array images reveal an edge-brightened (FR-II), double-lobed structure with a total ∼50 kpc extent, and 1.5 GHz power of 1.2 × 1025 W Hz−1, separated from the bright, arcsecond-scale core. We reanalyzed the Chandra data and found that the X-ray-emitting active galactic nucleus (AGN) is offset by ∼9 kpc from a compact X-ray cool-core with temperature kT = 3.1 ± 0.5 keV, and a radius of ∼22 kpc, surrounded by a hotter kT = 6.3 ± 0.7 keV gas out to ∼50 kpc. The offset suggests sloshing inside the cool-core induced by a minor merger or a past outburst of the AGN that produced large-scale radio lobes. The comparable spatial scales of the lobes with the interface between the different temperature X-ray plasmas indicate the lobes are actively heating the outer layers of what is now a remnant compact cool-core. Our dual-frequency Very Long Baseline Array (VLBA) images reveal substructure in the central radio source, consisting of a radio core with double-sided parsec-scale jets pointing toward the kiloparsec-scale structures. The northern jet is detected only at 8.4 GHz, indicating its emission is behind an absorbing torus or disk. We also measured faster apparent motions in the southern jet up to 1.9 ± 1.1c than in the northern jet (0.8 ± 0.5c). While the VLBA observations indicate the southern jet is aligned slightly closer to our line of sight, the asymmetries are overall modest and imply minimal projection effects in the large-scale radio structures.
XMM-Newton and Chandra Observations of the Unidentified Fermi-LAT Source 3FGL J1016.5–6034: A Young Pulsar with a Nebula?
Authors: Hare Jeremy , Volkov Igor , Kargaltsev Oleg , Younes George , Rangelov Blagoy
Published: April 2019

We report the discovery of a bright X-ray source in the XMM-Newton and Chandra X-Ray Observatory (Chandra) images of the unidentified Fermi-LAT source 3FGL J1016.5–6034. The XMM-Newton spectrum of the source is well fit by an absorbed blackbody+power-law model with a temperature kT = 0.20 ± 0.02 keV and photon index Γ = 1.8 ± 0.1. Chandra resolves the same source into a point source (CXOU J101546.0–602939) and a surrounding compact nebula seen up to about 30″ from the point source. The Chandra spectrum of the nebula can be described by an absorbed power law with Γ = 1.7 ± 0.3 and is partly responsible for the nonthermal emission observed in the XMM-Newton spectrum. The XMM-Newton images also reveal faint extended emission on arcminute scales. These properties strongly suggest that the X-ray source and the accompanying extended emission are a newly discovered young pulsar with a pulsar wind nebula. We also analyze ∼10 yr of Fermi-LAT data and find that the improved LAT source localization is consistent with the position of CXOU J101546.0–602939.
Electron Acceleration by ICME-driven Shocks at 1 au
Authors: Yang Liu , Wang Linghua , Li Gang , Wimmer-Schweingruber Robert F. , He Jiansen , Tu Chuanyi , Tian Hui , Bale Stuart D.
Published: April 2019

We present a comprehensive study of in situ electron acceleration during 74 shocks driven by interplanetary coronal mass ejections (ICMEs) with good suprathermal electron observations by the Wind 3DP instrument at 1 au from 1995 through 2014. Among the selected 59 quasi-perpendicular (15 quasi-parallel) shock cases, ∼86% (∼60%), ∼62% (∼36%), and ∼17% (∼7%) show significant electron flux enhancements of J

D
/J

A
 > 1.5 across the shock, respectively at 0.43, 1.95, and 40 keV, where J

D
and J

A
are the electron flux in the shock’s downstream and the preceding ambient solar wind. For significantly shocked suprathermal electrons, the differential flux J

D
positively correlates most with the magnetosonic Mach number M

s
, while the flux enhancement J

D
/J

A
positively correlates most with the magnetic compression ratio r

B
, among the shock parameters. Both J

D
and J

A
generally fit well to a double-power-law spectrum at ∼0.4–100 keV, J ∝ E
−β
, with an index of β
1 ∼ 2–6 below a break energy of E
br (which is typically ∼2 keV) and an index of β
2 ∼ 2.0–3.2 at energies above.

is similar to

in all the shock cases, while

is similar to (larger than)

in ∼60% (∼40%) of the shock cases with significant electron enhancements. Furthermore, J

D
/J

A
mostly peaks in the directions perpendicular to the interplanetary magnetic field at ∼0.4–50 keV. These results suggest that both quasi-parallel and quasi-perpendicular shocks accelerate electrons in situ at 1 au mainly via shock drift acceleration, with an acceleration efficiency probably affected by the induced electric field at the shock surface.
Spatially Resolved Outflows in a Seyfert Galaxy at z = 2.39
Authors: Fischer Travis C. , Rigby J. R. , Mahler G. , Gladders M. , Sharon K. , Florian M. , Kraemer S. , Bayliss M. , Dahle H. , Barrientos L. Felipe , Lopez S. , Tejos N. , Johnson T. , Wuyts E.
Published: April 2019

We present the first spatially resolved analysis of rest-frame optical and UV imaging and spectroscopy for a lensed galaxy at z = 2.39 hosting a Seyfert active galactic nucleus (AGN). Proximity to a natural guide star has enabled observations with high signal-to-noise ratio using Very Large Telescope SINFONI + adaptive optics (AO) of rest-frame optical diagnostic emission lines, which exhibit an underlying broad component with full width at half maximum ∼ 700 km s−1 in both the Balmer and forbidden lines. Measured line ratios place the outflow robustly in the region of the ionization diagnostic diagrams associated with AGNs. This unique opportunity—combining gravitational lensing, AO guiding, redshift, and AGN activity—allows for a magnified view of two main tracers of the physical conditions and structure of the interstellar medium in a star-forming galaxy hosting a weak AGN at Cosmic Noon. By analyzing the spatial extent and morphology of the Lyα and dust-corrected Hα emission, disentangling the effects of star formation and AGN ionization on each tracer, and comparing the AGN-induced mass outflow rate to the host star formation rate, we find that the AGN does not significantly impact the star formation within its host galaxy.
Evolution of the Coronal Cavity From the Quiescent to Eruptive Phase Associated with Coronal Mass Ejection
Authors: Sarkar Ranadeep , Srivastava Nandita , Mierla Marilena , West Matthew J , D’Huys Elke
Published: April 2019

We present the evolution of a coronal cavity encompassing its quiescent and eruptive phases in the lower corona. Using multiple vantage-point observations from the SDO/AIA, STEREO SECCHI/EUVI, and PROBA2/Sun Watcher with the APS and Image Processing (SWAP) extreme ultraviolet (EUV) imagers, we capture a sequence of quasi-static equilibria of the quiescent cavity, which exhibited a slow rise and an expansion phase during its passage on the solar disk from 2010 May 30 to June 13. By comparing the decay-index profiles of the cavity system during the different stages of its quiescent and pre-eruptive phases, we find that the decay-index value at the cavity centroid height can be used as a good indicator to predict the cavity eruption in the context of torus instability. Combining the observations of SWAP and the Large Angle and Spectrometric Coronagraph Experiment C2/C3, we show the evolution of the EUV cavity into the white-light cavity as a three-part structure of the associated coronal mass ejection that was observed to erupt on 2010 June 13. By applying successive geometrical fits to the cavity morphology, we find that the cavity exhibited non-self-similar expansion in the lower corona, below 2.2 ± 0.2 R
S, which points to the spatial scale for the radius of the source surface where the coronal magnetic field lines are believed to become radial. Furthermore, the kinematic study of the erupting cavity captures both the “impulsive” and “residual” phases of acceleration along with a strong deflection of the cavity at 1.3 R
S. We also discuss the role of driving forces behind the dynamics of the morphological and kinematic evolution of the cavity.
Atmospheres and UV Environments of Earth-like Planets throughout Post-main-sequence Evolution
Authors: Kozakis Thea , Kaltenegger Lisa
Published: April 2019

During the post-main-sequence (post-MS) phase of stellar evolution, the orbital distance of the habitable zone (HZ), which allows for liquid surface water on terrestrial planets, moves out past the system’s original frost line, providing an opportunity for outer planetary system surface habitability. We use a 1D coupled climate/photochemistry code to study the impact of the stellar environment on the planetary atmospheres of Earth-like planets/moons throughout its time in the post-MS HZ. We also explore the ground UV environments of such planets/moons and compare them to Earth’s. We model the evolution of star–planet systems with host stars ranging from 1.0 to 3.5 M
⊙ throughout the post-MS, calculating stellar mass loss and its effects on planetary orbital evolution and atmospheric erosion. The maximum amount of time a rocky planet can spend continuously in the evolving post-MS HZ ranges between 56 and 257 Myr for our grid stars. Thus, during the post-MS evolution of their host star, subsurface life on cold planets and moons could become remotely detectable once the initially frozen surface melts. Frozen planets or moons, like Europa in our solar system, experience a relatively stable environment on the horizontal branch of their host star’s evolution for millions of years.
A new striking and critically endangered species of Nasa (Loasaceae, Cornales) from North Peru
Authors: Henning Tilo , Acuña Castillo Rafael , Rodríguez Rodríguez Eric Frank , García Llatas Luis Felipe , Weigend Maximilian
Published: April 2019

Nasaangeldiazioidessp. nov.is described and illustrated. The species is restricted to two forest remnants on the western slope of the northern Peruvian Andes (Dept. Lambayeque) where it is found in the undergrowth of primary forest. The new taxon shows a unique leaf morphology in the family Loasaceae. Molecular and morphological data show that the new species belongs to theNasatriphyllagroup. Since the relic forests of the north-western Andes are increasingly threatened by the effects of climate change, i.e. droughts and wildfires, the new species already faces imminent extinction.
À prendre ou à laisser ?
Authors: Guien Jeanne
Published: April 2019

La pratique de la récupération alimentaire en milieu urbain (ou « freeganisme ») est l’occasion d’interactions et d’échanges avec les passants, les commerçants, les travailleurs des déchets ou les récupérateurs. Portant un regard autoethnographique sur six années de pratique régulière de la récupération alimentaire dans les rues parisiennes, l’auteure propose d’étudier ce que ces interactions parfois conflictuelles nous disent du statut ambigu du déchet, de la récupération et du corps féminin aujourd’hui.
Formalization of wastepickers in Bogota and Lima: Recognize, regulate, and then integrate?
Authors: Rateau Mélanie , Tovar Luisa
Published: April 2019

Waste management models in Colombia and Peru are at a turning point in favor of the integration of informal waste pickers. The Capital District of Bogota and Lima's fifty municipalities are putting in place formalization processes that are more than just a formality. It involves recognizing, regulating and integrating wastepickers. The study of the processes at work in these two cities reveals distinct models of formalization with contrasting impacts on the informality and the marginality of a practice and the population dedicated to it.
Waste, weeds, and wild food
Authors: Paddeu Flaminia
Published: April 2019

The aim of this paper is to define the scope and an initial agenda for a critical geography of urban food collecting. It provides an overview of a multidisciplinary literature regarding patterns of foraging and scavenging to develop a theoretical comprehension of urban collecting in contemporary northern cities. Drawing on three bodies of critical geography literature, namely urban informality studies, radical food studies, and urban political economy and ecology, it advocates that investigating urban food collecting provides a tool to analyze structural forms of power, exclusion, injustice and inequality as well as alternative pathways in spaces of advanced capitalism.
Penser la cueillette de plantes médicinales sauvages dans des sociétés en transition : le cas guyanais
Authors: Tareau Marc-Alexandre , Dejouhanet Lucie , Odonne Guillaume , Palisse Marianne , Ansoe Clarisse
Published: April 2019

La cueillette des plantes médicinales en Guyane française est une pratique relativement méconnue, sous-estimée et souvent perçue comme anecdotique ou insignifiante. Pourtant, tous les jours, des personnes peuvent être vues ramassant des plantes sur les bords de route, pour leur propre usage ou, dans de moindres proportions, pour les vendre. Cet article vise à caractériser ces pratiques de cueillette des plantes médicinales et leur diversité et à souligner la pertinence de l’entrée par ces plantes pour interroger le fonctionnement de sociétés sujettes à des transformations rapides et désignées ici comme « en transition ». À la lumière de deux études de cas, une sur la cueillette urbaine dans l’agglomération de Cayenne et l’autre en zone rurale le long du bas-Maroni, cet article permet de repenser les relations nature-société-ville. En observant les spécificités socio-culturelles influençant les modalités de cueillette, il propose un schéma conceptuel de ces pratiques en mobilisant les idées d’hétérogénéité et de finalité comme concepts explicatifs.
L’intégration des cueilleurs de déchets latino-américains ou la création d’une nouvelle marge
Authors: Durand Mathieu , De Oliveira Neves Fabio
Published: April 2019

Pendant des décennies, les villes latino-américaines ont lutté contre les récupérateurs informels de déchets, au titre de la priorisation du la sécurité sanitaire et de la logique hygiéniste. Aujourd’hui, les combats contre le gaspillage des ressources et contre la pauvreté aboutissent à la reconnaissance de l’activité des récupérateurs. Ces « cueilleurs » de déchets, agissant autrefois de façon autonome, sont aujourd’hui au cœur de l’action municipale du recyclage en Amérique Latine. Pour autant, les limites de ce modèle apparaissent rapidement. Partout où l’intégration des récupérateurs informels se stabilise, de nouvelles marges apparaissent et une compétition se met en place pour capter les gisements de déchets. Quelles relations se mettent alors en place entre les parties prenantes ? Le Pérou, la Colombie et le Brésil permettront d’illustrer cette question.
Normaliser le sauvage : l'expérience française des cueilleurs professionnels
Authors: Julliand Claire , Pinton Florence , Garreta Raphaële , Lescure Jean-Paul
Published: April 2019

L’engouement pour les produits naturels redynamise à l’échelle mondiale les cueillettes commerciales de plantes sauvages. En France métropolitaine, cette activité a longtemps été perçue comme marginale alors que plus de 10 % de la biodiversité végétale serait aujourd’hui concernée par cette économie du « sauvage ». Soucieux de se distancier des « pillages » qui agitent parfois les territoires ruraux et d’assurer la préservation des ressources végétales, des cueilleuses et des cueilleurs se sont réunis en 2011 au sein de l’Association française des professionnels de la Cueillette de plantes sauvages (AFC). Ce jeune collectif souhaite faire reconnaître le métier dans sa diversité et construire une éthique de la cueillette en concertation avec les acteurs des filières utilisatrices d’ingrédients naturels et les gestionnaires de l’environnement. Des collaborations avec des acteurs des milieux de la recherche et de la conservation ont permis de faire émerger une dynamique participative et réflexive pour accompagner ce processus de professionnalisation et penser les modalités de sa réalisation. A travers ce dispositif, les membres de l’AFC vont mettre à l’épreuve leurs valeurs, leurs savoir-faire et leurs rapports à la plante. En nous appuyant sur ces expériences partagées, des prémices de l’association au projet FloreS, nous proposons de discuter du renouveau des cueillettes commerciales en France métropolitaine.
Les outils SIG vus et vécus par les gestionnaires de crise à la Préfecture de Police de Paris
Authors: Di Tursi Fanny
Published: April 2019

Les outils cartographiques sont assez présents dans les services de la Préfecture de Police. Les gestionnaires de crise et acteurs opérationnels s’en servent quotidiennement pour assurer leurs diverses missions de veille, d’anticipation, de commandement, etc. Travaillant sur des terrains similaires, ces acteurs sont souvent amenés à intervenir sur un même événement pour maintenir la sécurité sur le lieu, que cela soit pour gérer un événement quotidien ou lors d’une crise. Leurs outils SIG étant identiques, et/ou alors étant développés sur une même plateforme, on peut alors s’interroger sur la bonne interopérabilité des outils entre les services et l’harmonisation de leurs données. A travers ces interrogations, nous présenterons les métiers autour des outils SIG.
Valoriser l’écologie pour légitimer le paysage ?
Authors: Roussel Fabien
Published: April 2019

Les pourtours végétalisés de l’agglomération parisienne – un temps concernés par un projet de ceinture verte – font l’objet de multiples aménagements « verts », d’échelles variables et mettant en valeur des enjeux écologiques. En croisant sources littéraires, analyses photographiques et croquis de paysage, l’article montre comment ces valeurs écologiques légitiment des valeurs paysagères. Celles-ci sont illustrées par les représentations des écrivains voyageurs, témoins d’un imaginaire urbain d’une nature champêtre. L’analyse de photographies montre que la valorisation écologique par les acteurs publics ne dépend pas que des caractéristiques floristico-écologiques des milieux mais aussi des usages et des pratiques. Pour finir, le croquis révèle la dimension paysagère de la végétation sur les pourtours de l’agglomération parisienne et permet d’éclairer sous un nouveau jour les intentions des acteurs publics dans des contextes territoriaux particuliers.
Investigation of Mechanical Behaviour of the Bone Cement (PMMA) under Combined Shear and Compression Loading
Authors: Khellafi Habib , Bouziane Mohammed Mokhtar , Djebli Abdelkader , Mankour Abdeldjalil , Bendouba Mustapha , Bachir Bouiadjra Bel Abbès , Ould Chikh El Bahri
Published: April 2019

Generally, implants fixations in orthopedic surgery are insured by bone cement; which is generated mainly from polymer polymethylmethacrylate (PMMA). Since, the cement is identified as the weakest part among bone-cement-prosthesis assembly. Hence, the characterization of mechanical behaviour is of a crucial requirement for orthopaedic surgeon’s success. In this study, we investigates the failure behaviour of bone cement, under combined shear and compression loading, for the aim to determine the strengths of bone cement for different mode loading conditions. Therefore, experimental cylindrical specimens has been tested to assess different shear-compression stresses. Based on the mechanical tests, a finite elements model of cylindrical specimens was developed to evaluate stresses distribution in the bone cement under compression, shear and combined shear-compression loading. Results show that, the load which leading to the failure of the cement decreased with increasing of the specimen angle inclination with respect of loading direction.
CNT Incorporated Polyacrilonitrile/Polypyrrole Nanofibers as Keratinocytes Scaffold
Authors: Ince Yardimci Atike , Aypek Hande , Ozturk Ozgur , Yilmaz Selahattin , Ozcivici Engin , Mese Gulistan , Selamet Yusuf
Published: April 2019

Polypyrrole (PPy) is an attractive scaffold material for tissue engineering with its non-toxic and electrically conductive properties. There has not been enough information about PPy usage in skin tissue engineering. The aim of this study is to investigate biocompatibility of polyacrilonitrile (PAN)/PPy nanofibrous scaffold for human keratinocytes. PAN/PPy bicomponent nanofibers were prepared by electrospinning, in various PPy concentrations and with carbon nanotube (CNT) incorporation. The average diameter of electrospun nanofibers decreased with increasing PPy concentration. Further, agglomerated CNTs caused beads and disordered parts on the surface of nanofibers. Biocompatibility of these PAN/PPy and PAN/PPy/CNT scaffolds were analyzed in vitro. Both scaffolds provided adhesion and proliferation of keratinocytes. Nanofiber diameter did not significantly influence the morphology of cells. However, with increasing number of cells, cells stayed among nanofibers and this affected their shape and size. In this study, we demonstrated that PAN/PPy and PAN/PPy/CNT scaffolds enabled the growth of keratinocytes, showing their biocompatibility.
Prospective analysis of factors predicting feasibility & success of longitudinal intussusception vasoepididymostomy in men with idiopathic obstructive azoospermia
Authors: Tiwari Devi Prasad , Razik Abdul , Das Chandan J. , Kumar Rajeev
Published: April 2019

Background & objectives:

Microsurgical reconstruction for idiopathic obstructive azoospermia is a challenging procedure, and selection of appropriate patients is important for successful outcomes. This prospective study was done to evaluate the ability of scrotal ultrasound measurements to predict the surgical feasibility and determine factors that could predict a patent anastomosis following vaso-epididymal anastomosis (VE) in men with idiopathic obstructive azoospermia.

Methods:

In this prospective study, men diagnosed with idiopathic obstructive azoospermia, scheduled for a longitudinal intussusception VE, underwent a scrotal ultrasound measurement of testicular and epididymal dimensions. During surgery, site and type of anastomosis, presence of sperms in the epididymal fluid and technical satisfaction with the anastomosis were recorded. All men where VE could be performed were followed up for appearance of sperms in the ejaculate. Ultrasound parameters were compared between men who had a VE versus those with negative exploration. Predictive factors were compared between men with or without a patent anastomosis.

Results:

Thirty four patients were included in the study conducted between September 2014 and August 2016 and a VE was possible in only 19 (55%) patients. Of these 19 patients, six had a patent anastomosis with one pregnancy. Preoperative ultrasound measurements could not identify patients where a VE could not be performed. Motile sperm in the epididymal fluid was the only significant predictor of a successful anastomosis.

Interpretation & conclusion:

Forty five per cent of men planned for a VE for idiopathic obstructive azoospermia could not undergo a reconstruction. Ultrasound assessment of testicular and epididymal dimensions could not predict the feasibility of performing a VE. The presence of motile sperms in the epididymal fluid was the only significant predictor of a patent VE in our study.
High degree of fluoroquinolone resistance among pulmonary tuberculosis patients in New Delhi, India
Authors: Sharma Rohini , Sharma Surendra Kumar , Singh Binit Kumar , Mittal Abhenil , Kumar Prahlad
Published: April 2019

Background & objectives:

The fluoroquinolones (FQs) group of antibiotics is the backbone drugs for the management of drug-resistant tuberculosis (TB). In routine clinical practice, drug susceptibility testing (DST) for FQs is not performed, and the patients are empirically treated. A limited information exists regarding FQs resistance among pulmonary TB cases. The present study was conducted to determine the FQs resistance among drug sensitive and drug-resistant pulmonary TB patients in a tertiary care centre in north India.

Methods:

A total of 1619 sputum/smear-positive specimens of pulmonary TB patients were subjected to DST for first-line drugs (FLDs) and second-line drugs. In addition, FQs DST was also performed using automated Mycobacterial Growth Indicator Tube-960 liquid culture technique. The immuno-chromatographic assay was performed to distinguish Mycobacterium tuberculosis complex (MTBC) from non-MTBC.

Results:

Mycobacterium tuberculosis (Mtb) was isolated in 1499 sputum specimens; 1099 culture specimens were sensitive to FLDs, 249 grew as multidrug-resistant (MDR) Mtb and the remaining 151 isolates revealed any drug resistance to FLDs. While FQs monoresistance among the FLD sensitive isolates was 3.1 per cent (35/1099), 27.3 per cent (68/249) among MDR Mtb isolates had additional FQs resistance.

Interpretation & conclusions:

FQs resistance among drug sensitive and MDR Mtb isolates was high in Delhi, India. Based on these findings, it is recommended that the DST for FQs should be routinely performed to avoid further amplification of drug resistance.
Non-alcoholic fatty liver disease associated with hepatocellular carcinoma
Authors: Dhamija Ekta , Paul Shashi Bala , Kedia Saurabh
Published: April 2019

Hepatocellular carcinoma (HCC) is the sixth most common cancer in world and third largest cause of cancer-related deaths. The last few decades have witnessed the emergence of non-viral causes of HCC, the most important being non-alcoholic fatty liver disease (NAFLD). NAFLD ranges from simple steatosis in the absence of excessive alcohol intake to non-alcoholic steatohepatitis (NASH) with or without cirrhosis. About 3-15 per cent of the obese patients with NASH progress to cirrhosis and about 4-27 per cent of NASH with cirrhosis patients transform to HCC. It is also known that HCC can develop de novo in patients with NASH without the presence of cirrhosis. Yearly cumulative incidence of NASH-related HCC is low (2.6%) compared to four per cent of viral-HCC. NAFLD has been associated with risk factors such as metabolic syndrome, insulin resistance, altered gut flora and persistent inflammation. Due to alarming rise in metabolic diseases, both in the developing as well as the developed world, it is expected that the incidence of NAFLD/NASH-HCC would rise manifold in future. No definite guidelines have been drawn for surveillance and management of NAFLD/NASH-associated HCC. It is thus important to discuss the entity of HCC in NAFLD at length with special focus on its epidemiology, risk factors, pathophysiology, diagnosis, clinical presentation and prevention.
A descriptive pilot study of mitochondrial mutations & clinical phenotype in fibromyalgia syndrome
Authors: Danda Sumita , Thomas Blessy Mariam , Paramasivam G. , Thomas Raji , Mathew John , Danda Debashish
Published: April 2019

Background & objectives:

Fibromyalgia syndrome (FMS) is one of the most common chronic pain conditions of unknown aetiology. Mitochondrial dysfunction has been reported in FMS with some studies reporting the presence of mitochondrial mutation namely A3243G, which also causes mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes. This pilot study was conducted to assess this mutation and also detect large deletions in mitochondrial DNA (mtDNA) in patients with FMS.

Methods:

Thirty female patients with FMS participated and 30 matched controls were included. Genomic DNA was subjected to polymerase chain reaction (PCR) amplification using specific primers followed by restriction digestion with ApaI enzyme to detect the specific A3243G mtDNA mutation. Long-range PCR was done in two sets to detect the large deletions in the mtDNA. Biochemical parameters including thyroid-stimulating hormone and vitamin D levels were also looked at.

Results:

None of the patients were found to carry the common mutation or large deletions. Low vitamin D level was a common finding. Hypothyroidism was found in a few patients.

Interpretation & conclusions:

Although the common mutation or large mtDNA deletions were not detected in blood mtDNA in the FMS patients, mutations in the muscle and sequence variation in mtDNA remained a possibility. Future studies in both blood and muscle tissue including mtDNA sequencing are warranted in such patients to determine if a subset of FMS patients have mitochondrial myopathy.