bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effect of Corporate Governance on Earnings Quality and Market Reaction to Low Quality Earnings: Korean Evidence
Authors: Shin Hyejeong , Kim Su-In
Published: December 2018

This study investigates whether corporate governance mechanisms are associated with earnings quality, especially accurate earnings reporting, and whether investors react differently to inaccurate earnings according to governance strength. Earnings accuracy is one of the key factors affecting a firm’s sustainability in the sense that reported earnings provide information about a firm’s long-term sustainability and further are directly associated with a firm’s cost of capital. In this paper, we employ the independence of the board of directors (BOD) and foreign ownership as governance mechanisms associated with the earnings gap between audited and unaudited earnings. Using 1976 non-financial firm-year observations listed on the Korea Stock Exchange from 2013 to 2016, we find that the gap between unaudited earnings and actual earnings is smaller for firms with independent BODs and foreign ownership, suggesting that earnings accuracy is higher for firms with effective corporate governance. This study also examines how investors react to the earnings gap. Stock returns to the earnings gap are less negative for firms with independent BODs and are more negative as foreign ownership increases, implying that each mechanism of corporate governance has different effects.
An Integral Approach to Sustainable Decision-Making within Maritime Spatial Planning—A DSC for the Planning of Anchorages on the Island of Šolta, Croatia
Authors: Jajac Nikša , Kilić Jelena , Rogulj Katarina
Published: December 2018

The planning of nautical tourism development and especially, the planning of its supporting infrastructure development, is important topic of the maritime spatial planning. The focus of research is the integration of multicriteria analysis and stakeholders within concept modeling that will provide support to the spatial planning specialists in the design of plans related to the development of anchorage capacities for small vessels. It examines economic, environmental, ecological, social, and civil engineering concerns related to the use of coastal water. It is a complex and ill-defined civil engineering problem because of multiple stakeholders with diverse interests, numerous conflicting goals and criteria, huge quantities of information and data, limited resources, etc. The research is concentrated on an integral approach to sustainable decision-making within maritime spatial planning by the modeling decision support concept to the processes of identification, validation, comparison, and the selection of locations for anchorage construction, based on multicriteria methods, goal analysis, and the logic of the decision support system. The concept is tested on the island of Šolta, Croatia, and has been proven as being an applicable, consistent, efficient, and effective methodology for the planning of the anchorage locations.
Prediction of Confusion Attempting Algebra Homework in an Intelligent Tutoring System through Machine Learning Techniques for Educational Sustainable Development
Authors: Abidi Syed Muhammad Raza , Hussain Mushtaq , Xu Yonglin , Zhang Wu
Published: December 2018

Incorporating substantial, sustainable development issues into teaching and learning is the ultimate task of Education for Sustainable Development (ESD). The purpose of our study was to identify the confused students who had failed to master the skill(s) given by the tutors as homework using the Intelligent Tutoring System (ITS). We have focused ASSISTments, an ITS in this study, and scrutinized the skill-builder data using machine learning techniques and methods. We used seven candidate models including: Naïve Bayes (NB), Generalized Linear Model (GLM), Logistic Regression (LR), Deep Learning (DL), Decision Tree (DT), Random Forest (RF), and Gradient Boosted Trees (XGBoost). We trained, validated, and tested learning algorithms, performed stratified cross-validation, and measured the performance of the models through various performance metrics, i.e., ROC (Receiver Operating Characteristic), Accuracy, Precision, Recall, F-Measure, Sensitivity, and Specificity. We found RF, GLM, XGBoost, and DL were high accuracy-achieving classifiers. However, other perceptions such as detecting unexplored features that might be related to the forecasting of outputs can also boost the accuracy of the prediction model. Through machine learning methods, we identified the group of students that were confused when attempting the homework exercise, to help foster their knowledge and talent to play a vital role in environmental development.
SMEs’ External Technology R&D Cooperation Network Diversity and Their Greenhouse Gas Emission Reduction and Energy Saving: A Moderated Mediation Analysis
Authors: Hau Yong Sauk
Published: December 2018

The purpose of this research is to empirically reveal the effect of external technology R&D cooperation network diversity (ETRDCND) on the greenhouse gas (GHG) emission reduction and energy saving of small and medium-sized enterprises (SMEs). Besides this, this study aims at analyzing the roles of production time reduction and absorptive capacity in the relationship between SMEs’ ETRDCND and their GHG emission reduction and energy saving. GHG emission and energy usage have been playing a crucial role in aggravating global warming. Global warming results in big problems such as worldwide unusual weather and health disorders. SMEs play a substantial role in the industrial growth of the global economy, which increases GHG emission and energy consumption. By performing the ordinary least squares regression with the data of 3300 South Korean SMEs, this research reveals four points. First, ETRDCND positively influences SMEs’ GHG emission reduction and energy saving. Second, production time reduction perfectly mediates the relationship between SMEs’ ETRDCND and their GHG emission reduction and energy saving. Third, the mediating role of production time reduction in this relationship is moderated by SMEs’ absorptive capacity. Fourth, ETRDCND significantly influences SMEs’ GHG emission reduction and their energy saving only if SMEs possess their own absorptive capacity.
Developing Evaluation Frameworks for Business Models in China’s Rural Markets
Authors: Zhang Xinxiang , Hu Lijun , Salimath Manjula , Kuo Ching-Chung
Published: December 2018

In rural China, successful and sustainable business model design has been viewed as an important strategy to achieve a win–win scenario in which rural poverty can be alleviated and enterprise profit can be improved. Although business model related literature is strong, it lacks a comprehensive framework for appraising business models in rural markets. As a result, entrepreneurs are facing significant challenges in implementing their market development centered business models or resource development centered business models. This study draws on case analysis to present two frameworks for evaluating the two types of business models, respectively. Through open coding and axial coding on eight Chinese cases, we identify the main components for the evaluation frameworks and critical factors within each component. Using the coding results as a lens, we apply a cross-case comparative data analysis to establish the multi-level evaluation systems. Finally, we provide suggestions for entrepreneurs and other stakeholders to better their business model design in China’s rural markets.
Management of Waste Collection from Yachts and Tall Ships from the Perspective of Sustainable Water Tourism
Authors: Łapko Aleksandra , Strulak-Wójcikiewicz Roma , Landowski Marek , Wieczorek Radosław
Published: December 2018

This article deals with the issue of waste collection from yachts and tall ships that is important from the perspective of sustainable tourism. There are, of course, procedures that regulate the passing of waste by vessels, which also apply to tourist vessels. However, the authors made an attempt to analyze the process of waste collection carried out under non-standard conditions, i.e., during a mass event held at the port of the Tall Ships Races final, which took place in 2017 in Szczecin. Many yachts and tall ships participated in the event, and in addition, due to the multiplicity of attractions, the event area was very popular among tourists and visitors (over one and a half million people in three days). Due to the safety of the participants, and the need to maintain high aesthetic standards, the procedures for collecting waste from vessels had to be modified. In addition to the preparation of a flowchart on which the existing procedural modifications were presented, based on the source data received from the waste collection company, quantitative and structural analyses of the waste were carried out. The conducted research showed that the waste collection required the coordination of the activities of many entities. This article also draws attention to operational problems that occurred during waste collection from vessels during the Tall Ships Races final. Statistical analysis allowed for the determination of the days where the vessels disposed the most solid and liquid waste, and how the structure of the amount of collected waste was shaped. The Tall Ships Races is the most popular and the biggest event of this type in the world—gathering the largest number of tall ships. They are carried out annually, and their route leads through various ports; however, the regatta final is the culminating point that attracts the largest number of tourists. For this reason, many cities are trying to become its organizers. In 2018, the finals took place in the Dutch port of Harlingen, and in 2019, the Danish port of Aarhus will be responsible for its organization. Two years later, in 2021, the Tall Ships Races regatta final will be hosted by Szczecin again. The results of the research conducted in this article may be helpful for appropriate preparation by subsequent ports for waste collection, which may contribute to the safety of the participants taking part in the event.
Cost of Caregivers for Treating Hospitalized Diarrheal Patients in Bangladesh
Authors: Sarker Abdur Razzaque , Sultana Marufa , Ali Nausad , Akram Raisul , Alam Khorshed , Khan Jahangir A.M. , Morton Alec
Published: December 2018

Introduction: Diarrheal diseases are a global public health problem and one of the leading causes of mortality, morbidity and economic loss. The objective of the study is to estimate the economic cost of caregivers and cost distribution per diarrheal episodes in Bangladesh. Methods: This was a cross-sectional hospital-based study conducted in public hospitals in Bangladesh. A total of 801 diarrheal patients were randomly selected and interviewed during January to December 2015. Simple descriptive statistics including frequencies, percentage, mean with 95% CI and median are presented. Results: The overall average cost of caregivers was BDT 2243 (US$ 28.58) while only BDT 259 (US$ 3.29) was spent as out of pocket payments. Caregivers mostly spent money (US$ 1.63) for food, lodging, utility bills, and other lump sum costs followed by the transportation costs (US$ 1.57). The caregivers spent more (US$ 44.45) when they accompanied the patients who were admitted in inpatients care and almost 3.6 times higher than for out-patients care (US$ 12.42). Conclusions: The study delivers an empirical evidence to the health-care programmers and policy makers about the economic cost of caregivers during diarrheal treatment care, which should be accounted for in designing future diarrheal prevention programme.
How is Location Measured in Housing Valuation? A Systematic Review of Accessibility Specifications in Hedonic Price Models
Authors: Heyman Axel Viktor , Law Stephen , Berghauser Pont Meta
Published: December 2018

Accessibility is frequently used for measuring location in housing studies, but specifications of the measures differ greatly and its implications are hardly discussed. This paper sets out to systematically review accessibility measures that are used in hedonic price models (HPM), a method for estimating the implicit value of housing characteristics, such as location. From a systematic database search of peer-reviewed journal articles, we examined 54 articles that applies accessibility measures in hedonic price models that are based on three aspects of measure specification: type, impedance, and opportunities. We find that there are clear couplings between different impedances, types, and opportunities. We also noticed a tendency towards less advanced measurements, such as Euclidean distance and zonal measures, being used. Furthermore, we argue that these basic measures have a weaker connection to consumer perception, which is fundamental to the hedonic price approach. We also observed a lack of consideration to how this coupling between type, impedance, and opportunity could possibly affect the results. Theoretically, we can already conclude that some dominating impedances poorly relate to the fundamental theories of HPM, but this also points to the need for further research to empirically test the influence of the type-impedance-opportunity specification on the price estimates in HPM.
Involvement of Surfactant Protein D in Ebola Virus Infection Enhancement via Glycoprotein Interaction
Authors: Favier Anne-Laure , Reynard Olivier , Gout Evelyne , van Eijk Martin , Haagsman Henk P. , Crouch Erika , Volchkov Viktor , Peyrefitte Christophe , Thielens Nicole M.
Published: December 2018

Since the largest 2014–2016 Ebola virus disease outbreak in West Africa, understanding of Ebola virus infection has improved, notably the involvement of innate immune mediators. Amongst them, collectins are important players in the antiviral innate immune defense. A screening of Ebola glycoprotein (GP)-collectins interactions revealed the specific interaction of human surfactant protein D (hSP-D), a lectin expressed in lung and liver, two compartments where Ebola was found in vivo. Further analyses have demonstrated an involvement of hSP-D in the enhancement of virus infection in several in vitro models. Similar effects were observed for porcine SP-D (pSP-D). In addition, both hSP-D and pSP-D interacted with Reston virus (RESTV) GP and enhanced pseudoviral infection in pulmonary cells. Thus, our study reveals a novel partner of Ebola GP that may participate to enhance viral spread.
Review of Pedestrian Load Models for Vibration Serviceability Assessment of Floor Structures
Authors: Muhammad Zandy , Reynolds Paul , Avci Onur , Hussein Mohammed
Published: December 2018

Innovative design and technological advancements in the construction industry have resulted in an increased use of large, slender and lightweight floors in contemporary office buildings. Compounded by an ever-increasing use of open-plan layouts with few internal partitions and thus lower damping, floor vibration is becoming a governing limit state in the modern structural design originating from dynamic footfall excitations. This could cause annoyance and discomfort to building occupants as well as knock-on management and financial consequences for facility owners. This article presents a comprehensive review pertinent to walking-induced dynamic loading of low-frequency floor structures. It is intended to introduce and explain key walking parameters in the field as well as summarise the development of previous walking models and methods for vibration serviceability assessment. Although a number of walking models and design procedures have been proposed, the literature survey highlights that further work is required in the following areas; (1) the development of a probabilistic multi-person loading model which accounts for inter- and intra-subject variabilities, (2) the identification of walking paths (routes accounting for the effect of occupancy patterns on office floors) coupled with spatial distribution of pedestrians and (3) the production of a statistical spatial response approach for vibration serviceability assessment. A stochastic approach, capable of taking into account uncertainties in loading model and vibration responses, appears to be a more reliable way forward compared to the deterministic approaches of the past and there is a clear need for further research in this area.
Applying 3D Geostatistical Simulation to Improve the Groundwater Management Modelling of Sedimentary Aquifers: The Case of Doñana (Southwest Spain)
Authors: Naranjo-Fernández Nuria , Guardiola-Albert Carolina , Montero-González Esperanza
Published: December 2018

Mathematical groundwater modelling with homogeneous permeability zones has been used for decades to manage water resources in the Almonte-Marismas aquifer (southwest Spain). This is a highly heterogeneous detrital aquifer which supports valuable ecological systems in the Doñana National Park. The present study demonstrates that it is possible to better characterize this heterogeneity by numerical discretization of the geophysical and lithological data available. We identified six hydrofacies whose spatial characteristics were quantified with indicator variogram modelling. Sequential Indicator Simulation then made it possible to construct a 3D geological model. Finally, this detailed model was included in MODFLOW through the Model Muse interface. This final process is still a challenge due to the difficulty of downscaling to a handy numerical modelling scale. New piezometric surfaces and water budgets were obtained. The classical model with zones and the model with 3D simulation were compared to confirm that, for management purposes, the effort of improving the geological heterogeneities is worthwhile. This paper also highlights the relevance of including subsurface heterogeneities within a real groundwater management model in the present global change scenario.
Evolution of Thermally Driven Disk Wind in the Black Hole Binary 4U 1630–47 Observed with Suzaku and NuSTAR
Authors: Hori Takafumi , Ueda Yoshihiro , Done Chris , Shidatsu Megumi , Kubota Aya
Published: December 2018

We performed simultaneous observations with Suzaku and NuSTAR of the Galactic black hole binary 4U 1630−47 in the high/soft state (HSS) during the 2015 outburst. To compare our results with those observed in the HSS at lower luminosities, we reanalyze the Suzaku data taken during the 2006 outburst. The continuum can be well explained by thermal disk emission and a hard power-law tail. All spectra show strong iron-K absorption line features, suggesting that a disk wind is always developed in the HSS. We find that the degree of ionization of the wind dramatically increased at the brightest epoch in 2015, when the continuum became harder. Detailed XSTAR simulations show that this cannot be explained solely by an increase of the photoionization flux. Instead, we show that the observed behavior in the HSS is consistent with a theory of thermally driven disk winds, where the column density and the ionization parameter of the disk wind are proportional to the luminosity and the Compton temperature, respectively.
PALFA Single-pulse Pipeline: New Pulsars, Rotating Radio Transients, and a Candidate Fast Radio Burst
Authors: Patel C. , Agarwal D. , Bhardwaj M. , Boyce M. M. , Brazier A. , Chatterjee S. , Chawla P. , Kaspi V. M. , Lorimer D. R. , McLaughlin M. A. , Parent E. , Pleunis Z. , Ransom S. M. , Scholz P. , Wharton R. S. , Zhu W. W. , Alam M. , Valdez K. Caballero , Camilo F. , Cordes J. M. , Crawford F. , Deneva J. S. , Ferdman R. D. , Freire P. C. C. , Hessels J. W. T. , Nguyen B. , Stairs I. , Stovall K. , Leeuwen J. van
Published: December 2018

We present a new single-pulse pipeline for the PALFA survey to efficiently identify single radio pulses from pulsars, rotating radio transients (RRATs), and fast radio bursts (FRBs). We conducted a sensitivity analysis of this new pipeline in which many single pulses were injected into PALFA data and run through the pipeline. We find that for single pulse widths <5 ms, the sensitivity of our new pipeline is at most a factor of ∼2 less sensitive than theoretically predicted. For pulse widths >10 ms, as the DM decreases, the degradation in sensitivity gets worse and can increase up to a factor of ∼4.5. Using this pipeline, we have discovered seven pulsars and two RRATs, and identified three candidate RRATs and one candidate FRB. The confirmed pulsars and RRATs have DMs ranging from 133 to 386 pc cm−3 and flux densities ranging from 20 to 160 mJy. The pulsar periods range from 0.4 to 2.1 s. We report on candidate FRB 141113, which is likely astrophysical and extragalactic, having DM ≃ 400 pc cm−3, which is over the Galactic maximum along this line of sight by ∼100–200 pc cm−3. We consider implications for the FRB population and show via simulations that if FRB 141113 is real and extragalactic, the slope α of the distribution of integral source counts as a function of flux density (N(>S) ∝ S
−α
) is 1.4 ± 0.5 (95% confidence range). However, this conclusion is dependent on assumptions that require verification.
Radiation-hydrodynamic Simulations of Spherical Protostellar Collapse for Very Low-mass Objects
Authors: Stamer Torsten , Inutsuka Shu-ichiro
Published: December 2018

We perform radiation-hydrodynamical simulations of protostellar collapse in spherical symmetry, with a special focus on very low-mass objects, i.e., brown dwarfs and sub-brown dwarfs. The inclusion of a realistic equation of state, which includes the effect of hydrogen dissociation, allows for a modeling of the complete process from the beginning of the collapse until the formation of the protostar. We solve the frequency-dependent radiative transfer equation without any diffusion approximation, using realistic dust and gas opacities. Our results show that the properties of the protostar are essentially independent of the initial conditions, which had previously only been confirmed for higher mass ranges. For very low-mass initial conditions, however, we find that the first core phase of the collapse shows some significant differences in the time evolution, with the first core lifetime increasing dramatically because of the reduced accretion rate from the surrounding envelope. We consider the observational implications of this. We also investigate the opposite case of a collapse without any first core phase, which may occur for very unstable initial conditions. In the Appendix, we describe a severe numerical problem that causes an unphysical expansion after the formation of the protostar, which may affect other attempts at similar calculations of self-gravitational collapse. We explain the origin of the unphysical behavior and present a solution that can be used in similar investigations.
Revisiting the Spatially Dependent Propagation Model with the Latest Observations of Cosmic-Ray Nuclei
Authors: Liu Wei , Yao Yu-hua , Guo Yi-Qing
Published: December 2018

Recently the AMS-02 collaboration published detections of light cosmic-ray nuclei, including lithium, beryllium, boron, carbon, and oxygen. Combined with the released energy spectra of proton and helium, both primary and secondary spectra have a prominent hardening above ∼200 GV. In particular, the spectral variation of secondary cosmic rays is greater than the primary ones. One of the plausible interpretations for the above anomalies is the spatial-dependent diffusion model. It has successfully described various observational phenomena, e.g., hardening of primary nuclei, diffuse gamma-ray distribution and cosmic-ray anisotropy, etc. In this work, we apply the spatial-dependent propagation model to the latest observations, including both primary and secondary nuclei. Apart from the primary components, the spectra of secondary nuclei can be properly reproduced as well, especially the upturn above 200 GV. We also calculate the ratios of both secondary-to-primary and secondary-to-secondary. We find that except for the Be/B ratio, the computations of the spatial-dependent propagation model are in good agreement with the current data.
Magnetic Loops above a Small Flux-emerging Region Observed by IRIS, Hinode, and SDO
Authors: Huang Zhenghua
Published: December 2018

I report on observations of a set of magnetic loops above a region with late-phase flux emergence taken by IRIS, Hinode, and SDO. The loop system consists of many transition-region loop threads that are 5″–12″ in length and ∼0.″5 in width and coronal loops with similar length and ∼2″ width. Although the loop system consists of threads with different temperatures, most individual loop threads have temperatures in a narrow range. In the middle of the loop system, there is a clear systematic blueshift of about 10 km s−1 in the transition region that is consistent with a flux-emerging picture, while a redshift of about 10 km s−1 in the corona is observed. The nonthermal velocity of the loop system is smaller than that of the surrounding region in the transition region but is comparable that in the corona. The electron densities of the coronal counterpart of the loop system range from 1 × 109 cm−3 to 4 × 109 cm−3. The electron density of a transition-region loop is also measured and found to be about 5 × 1010 cm−3, a magnitude larger than that in the coronal loops. In agreement with imaging data, the temperature profiles derived from the differential emission measurement technique confirm that some of the loops have been heated to corona level. Our observations indicate that the flux emergence in its late phase is much different from that at the early stage. While the observed transition region is dominated by emerging flux, these emerging loops could be heated to corona level, and the heating (if via nonthermal processes) most likely takes place only after they reach the transition region or lower corona.
Three-dimensional Magnetic Reconnection Triggering an X-class Confined Flare in Active Region 12192
Authors: Li Ting , Hou Yijun , Yang Shuhong , Zhang Jun
Published: December 2018

We present an extensive analysis of the X2.0-class confined flare on 2014 October 27 in the great active region, AR 12192, observed by the Interface Region Imaging Spectrograph and the Solar Dynamics Observatory. The slipping motion of the substructures within the negative-polarity flare ribbon (R1) and continual reconnection-induced flows during the confined flare are first presented. The substructures within ribbon R1 were observed to slip in opposite directions at apparent speeds of 10–70 km s−1. The slipping motion exhibited the quasi-periodic pattern with a period of 80–110 s, which can be observed since the flare start and throughout the impulsive phase of the flare. Simultaneously quasi-periodic flows moved along a reverse S-shaped filament, with an average period of about 90 s. The period of reconnection-induced flows is similar to that of the slippage of ribbon substructures, implying the occurrence of quasi-periodic slipping magnetic reconnection. The spectral observations showed that the Si iv line was blueshifted by 50–240 km s−1 at the location of the flows. During the process of the flare, the filament did not show the rise phase and was not associated with any failed eruption. The flare mainly consisted of two sets of magnetic systems, with both of their east ends anchoring in ribbon R1. We suggest that the slipping magnetic reconnection between two magnetic systems triggers the confined flare.
Chandra Observations of NuSTAR Serendipitous Sources near the Galactic Plane
Authors: Tomsick John A. , Lansbury George B. , Rahoui Farid , Aird James , Alexander David M. , Clavel Maïca , Cuturilo AnaSofija , Fornasini Francesca M. , Hong JaeSub , Klindt Lizelke , Stern Daniel
Published: December 2018

The Nuclear Spectroscopic Telescope Array (NuSTAR) serendipitous survey has already uncovered a large number of active galactic nuclei (AGNs), providing new information about the composition of the cosmic X-ray background. For AGNs off the Galactic plane, it has been possible to use existing X-ray archival data to improve source localizations, identify optical counterparts, and classify the AGNs with optical spectroscopy. However, near the Galactic plane, better X-ray positions are necessary to achieve optical or near-IR identifications due to the higher levels of source crowding. Thus, we have used observations with the Chandra X-ray Observatory to obtain the best possible X-ray positions. With eight observations, we have obtained coverage for 19 NuSTAR serendips within 12° of the plane. One or two Chandra sources are detected within the error circle of 15 of the serendips, and we report on these sources and search for optical counterparts. For one source (NuSTAR J202421+3350.9), we obtained a new optical spectrum and detected the presence of hydrogen emission lines. The source is Galactic, and we argue that it is likely a cataclysmic variable. For the other sources, the Chandra positions will enable future classifications in order to place limits on faint Galactic populations, including high-mass X-ray binaries and magnetars.
The Disk Substructures at High Angular Resolution Project (DSHARP). II. Characteristics of Annular Substructures
Authors: Huang Jane , Andrews Sean M. , Dullemond Cornelis P. , Isella Andrea , Pérez Laura M. , Guzmán Viviana V. , Öberg Karin I. , Zhu Zhaohuan , Zhang Shangjia , Bai Xue-Ning , Benisty Myriam , Birnstiel Tilman , Carpenter John M. , Hughes A. Meredith , Ricci Luca , Weaver Erik , Wilner David J.
Published: December 2018

The Disk Substructures at High Angular Resolution Project (DSHARP) used ALMA to map the 1.25 mm continuum of protoplanetary disks at a spatial resolution of ∼5 au. We present a systematic analysis of annular substructures in the 18 single-disk systems targeted in this survey. No dominant architecture emerges from this sample; instead, remarkably diverse morphologies are observed. Annular substructures can occur at virtually any radius where millimeter continuum emission is detected and range in widths from a few astronomical units to tens of astronomical units. Intensity ratios between gaps and adjacent rings range from near-unity to just a few percent. In a minority of cases, annular substructures coexist with other types of substructures, including spiral arms (3/18) and crescent-like azimuthal asymmetries (2/18). No clear trend is observed between the positions of the substructures and stellar host properties. In particular, the absence of an obvious association with stellar host luminosity (and hence the disk thermal structure) suggests that substructures do not occur preferentially near major molecular snowlines. Annular substructures like those observed in DSHARP have long been hypothesized to be due to planet–disk interactions. A few disks exhibit characteristics particularly suggestive of this scenario, including substructures in possible mean-motion resonance and “double gap” features reminiscent of hydrodynamical simulations of multiple gaps opened by a planet in a low-viscosity disk.
The Disk Substructures at High Angular Resolution Project (DSHARP). I. Motivation, Sample, Calibration, and Overview
Authors: Andrews Sean M. , Huang Jane , Pérez Laura M. , Isella Andrea , Dullemond Cornelis P. , Kurtovic Nicolás T. , Guzmán Viviana V. , Carpenter John M. , Wilner David J. , Zhang Shangjia , Zhu Zhaohuan , Birnstiel Tilman , Bai Xue-Ning , Benisty Myriam , Hughes A. Meredith , Öberg Karin I. , Ricci Luca
Published: December 2018

We introduce the Disk Substructures at High Angular Resolution Project (DSHARP), one of the initial Large Programs conducted with the Atacama Large Millimeter/submillimeter Array (ALMA). The primary goal of DSHARP is to find and characterize substructures in the spatial distributions of solid particles for a sample of 20 nearby protoplanetary disks, using very high resolution (∼0.″035, or 5 au, FWHM) observations of their 240 GHz (1.25 mm) continuum emission. These data provide a first homogeneous look at the small-scale features in disks that are directly relevant to the planet formation process, quantifying their prevalence, morphologies, spatial scales, spacings, symmetry, and amplitudes, for targets with a variety of disk and stellar host properties. We find that these substructures are ubiquitous in this sample of large, bright disks. They are most frequently manifested as concentric, narrow emission rings and depleted gaps, although large-scale spiral patterns and small arc-shaped azimuthal asymmetries are also present in some cases. These substructures are found at a wide range of disk radii (from a few astronomical units to more than 100 au), are usually compact (≲10 au), and show a wide range of amplitudes (brightness contrasts). Here we discuss the motivation for the project, describe the survey design and the sample properties, detail the observations and data calibration, highlight some basic results, and provide a general overview of the key conclusions that are presented in more detail in a series of accompanying articles. The DSHARP data—including visibilities, images, calibration scripts, and more—are released for community use at https://almascience.org/alma-data/lp/DSHARP.
The Disk Substructures at High Angular Resolution Project (DSHARP). III. Spiral Structures in the Millimeter Continuum of the Elias 27, IM Lup, and WaOph 6 Disks
Authors: Huang Jane , Andrews Sean M. , Pérez Laura M. , Zhu Zhaohuan , Dullemond Cornelis P. , Isella Andrea , Benisty Myriam , Bai Xue-Ning , Birnstiel Tilman , Carpenter John M. , Guzmán Viviana V. , Hughes A. Meredith , Öberg Karin I. , Ricci Luca , Wilner David J. , Zhang Shangjia
Published: December 2018

We present an analysis of Atacama Large Millimeter/submillimeter Array 1.25 mm continuum observations of spiral structures in three protoplanetary disks from the Disk Substructures at High Angular Resolution Project. The disks around Elias 27, IM Lup, and WaOph 6 were observed at a resolution of ∼40–60 mas (∼6–7 au). All three disks feature m = 2 spiral patterns in conjunction with annular substructures. Gas kinematics established by 12CO J = 2−1 observations indicate that the continuum spiral arms are trailing. The arm–interarm intensity contrasts are modest, typically less than 3. The Elias 27 spiral pattern extends throughout much of the disk, and the arms intersect the gap at R ∼ 69 au. The spiral pattern in the IM Lup disk is particularly complex—it extends about halfway radially through the disk, exhibiting pitch angle variations with radius and interarm features that may be part of ring substructures or spiral arm branches. Spiral arms also extend most of the way through the WaOph 6 disk, but the source overall is much more compact than the other two disks. We discuss possible origins for the spiral structures, including gravitational instability and density waves induced by a stellar or planetary companion. Unlike the millimeter continuum counterparts of many of the disks with spiral arms detected in scattered light, these three sources do not feature high-contrast crescent-like asymmetries or large (R > 20 au) emission cavities. This difference may point to multiple spiral formation mechanisms operating in disks.
Humanidades y ciencias: levantar la denegación
Authors: González de Ávila Manuel
Published: December 2018

Este artículo presenta los contenidos del número monográfico de Arbor insertándolos en las actuales condiciones epistémicas y epistemológicas para el ejercicio de las humanidades, y rastreando en la evolución social los fenómenos que apuntan a la necesidad de que los saberes humanísticos colaboren con las ciencias sociales, naturales y formales.
Ciencias inexactas y literaturas exactas. Lo que va del affaire Sokal a la poética de la materia de Bachelard
Authors: González Alcantud José Antonio
Published: December 2018

Los límites entre las humanidades y las ciencias se han desplazado y traspasado en innumerables ocasiones en las últimas décadas. El uso de la ciencia en los estudios humanísticos y de la metáfora cultural en los científicos está abundantemente documentado. Fértiles en especial han sido, por ejemplo, las teorías de la termodinámica (entropía), de la topología, de las catástrofes y de los fractales. El físico y matemático Alan Sokal, sin embargo, denunció la instrumentalización abusiva de la ciencia por ciertos teóricos de la literatura, filósofos y psicoanalistas, entre otros. El escándalo provocado por Sokal en 1996 oculta, no obstante, empleos legítimos de las ciencias por las humanidades, como el que Gaston Bachelard ilustró, tras despejar los obstáculos epistemológicos previos, con su creación de una poética de la materia.
Du lexique aux talismans : occurrences de la peste dans la Corne de l’Afrique du XIIIe au XVe siècle
Authors: Derat Marie-Laure
Published: December 2018

Les recherches les plus récentes au sujet de la peste invitent les chercheurs à élargir la chronologie et la géographie de la Grande Peste. Selon la chronologie communément admise, la peste noire s'est répandue en Europe occidentale de 1347 à 1350. Mais il est maintenant évident que des foyers de peste sont apparus au Proche et au Moyen-Orient bien après le milieu du xive siècle. En Égypte, la documentation historique évoque des épidémies de peste au xve siècle, avec des vagues régulières en 1403, 1407, 1430, 1460 et après. De nombreuses sources écrites éthiopiennes font état de pandémies qui secouent le royaume et causent des milliers de morts. Chroniques, Vies des saints regorgent de notations éparses sur la nécessité d'enterrer les victimes de ces pandémies selon des méthodes particulières. Les saints incarnent des figures de guérison miraculeuse et la lecture, lors des offices, de textes hagiographiques qui leur sont dédiés confère de l’espoir aux victimes de ces pandémies. Mais sur la base de ces témoignages, il est souvent impossible d'identifier la maladie à l'origine de la pandémie. La synchronie entre les pandémies observées en Égypte et dans la péninsule Arabique et celles observées en Éthiopie ainsi que les liens diplomatiques, commerciaux et religieux entre ces régions permettent d'interpréter certaines des pandémies décrites dans les sources éthiopiennes comme des pandémies de peste. Après une présentation des sources éthiopiennes traitant des pandémies du xiiie au xve siècle, du vocabulaire utilisé pour désigner ces épidémies et de l'identification des maladies en cause, l'article donne un aperçu des épidémies de peste dans les régions voisines de l'Éthiopie et examine les liens de la Corne de l'Afrique avec ces régions. Le dernier axe se concentre sur les réponses sociales aux épidémies en Éthiopie et tente de les identifier et de les singulariser, en fonction des attitudes adoptées. L'introduction de la commémoration de saint Roch dans le synaxaire éthiopien et dans les recueils de prières magiques éthiopiennes dissipe enfin le doute quant à la probabilité d'une épidémie de peste en Éthiopie.
Recognizing plague epidemics in the archaeological record of West Africa
Authors: Gallagher Daphne E. , Dueppen Stephen A.
Published: December 2018

Many archaeological sites in the central West African savanna were either abandoned or reduced in size between the 14th and 15th centuries CE. Explanations have tended to invoke the effects of climate change (increasing aridity), political transformations, and religious conversion. However, more recently scholars have increasingly suggested that this regional pattern could be in part the result of plague epidemics. In this paper we explore the methodological challenges inherent in linking abandonments with the effects of epidemics in the archaeological record through a contextualized examination of settlement pattern data from recent archaeological research at sites in Burkina Faso and Mali. While plague cannot be definitively identified based on settlement pattern data alone, current evidence supports the possibility that plague affected populations in this area of West Africa. A broader view of sites throughout West Africa indicates that the possible effects of plague were widespread.
Network Manipulation Using Network Scanning in SDN
Authors: M. Thangavel , V. Pavithra , R. Guru Roja
Published: December 2018

Network scanning commonly implies the use of the computer network to collect information about the target systems. This type of scanning is performed by hackers for attacking the target and also by the system administrators for assessment of security and maintaining the system. Network scanning mainly analyzes the UDP and TCP network services that are running on the target, the operating system that is used by the target, and the security systems that are placed between the user and targeted hosts. Network scanning includes both the network port scanning and vulnerability scanning. Network manipulation is an effort that is made by the user to modify the network or structure of a network and thus using online network tools to achieve the target. Software-defined networking is a term that comprises several network technologies with the aim of making it adapt the features of flexibility. Key terms for SDN implementation include separation of functionality, virtualization in the network, and configuring programmatically. This chapter explores network manipulation using network scanning in SDN.
Beyond Instructional Engagement
Authors: Francisco Dorcas
Published: December 2018

Faculty functions as the foundation for student engagement in higher education. Nowhere else is such a claim more evident than in the higher education online teaching environment. Evolutionary changes have taken place in higher education due to the nature of online education, which has transformed the traditional role of faculty. Higher education faculty roles have shifted from serving as content experts and researchers into roles that require the provision of more comprehensive and expansive support for students. In the online higher education industry, faculty members have been assigned tasks that increasingly cover multiple responsibilities that are typically the purview of technology helpdesk specialists, social workers, managers, student advisors, and customer service personnel. These wide-ranging obligations often hold online faculty accountable to numerous stakeholders. This chapter explores how the changing function of higher education faculty and institutions have a direct impact on instructors' ability to successfully create engaging learning environments.
Knowledge Management and Business Analytics
Authors: Honest Nirali Nikhilkumar , Patel Atul
Published: December 2018

Knowledge management (KM) is a systematic way of managing the organization's assets for creating valuable knowledge that can be used across the organization to achieve the organization's success. A broad category of technologies that allows for gathering, storing, accessing, and analyzing data to help business users make better decisions, business intelligence (BI) allows analyzing business performance through data-driven insight. Business analytics applies different methods to gain insight about the business operations and make better fact-based decisions. Big data is data with a huge size. In the chapter, the authors have tried to emphasize the significance of knowledge management, business intelligence, business analytics, and big data to justify the role of them in the existence and development of an organization and handling big data for a virtual organization.
Teachers' Decision-Making Process
Authors: Ferguson Britt Tatman , Evans Suzanne , Thorsos Nilsa J.
Published: December 2018

This chapter examines teachers' decision-making processes of selecting and implementing inclusive literature, especially in relation to children with disabilities, in their teaching practices. Inclusive literature celebrates diversity helping the individual see himself as well as others. Inclusive literature educates everybody about everyone, and books can help reduce prejudice. Diversity in literature impacts how children view disability and allows them to understand society. Realistic portrayals of a character with a disability can have positive impact on attitudes of students without disabilities towards peers with disabilities. The chapter will address effective strategies for selecting relevant and appropriate stories and books. In addition, the chapter will address effective strategies for using inclusive literature.
High Strength High Ductility Low Alloyed Steel
Authors: Arlazarov Artem , Hell Jean-Christophe , Oberbillig Carla , Kegel Frédéric
Published: December 2018

Annealed Martensite Matrix (AMM) concept was studied on two steel grades with low alloyed base composition of Fe-C-Mn-Si and two levels of Nb. Conditions for the thermal treatments were selected based on the experimental dilatometry tests and thermodynamic calculations. Annealing trials with short austempering holding were performed in the laboratory salt pots. Mechanical properties of heat treated steels have been investigated by tensile tests. Associated microstructures have been analyzed using Scanning Electron Microscopy as well as magnetization saturation method for measuring retained austenite fractions. Excellent strength-ductility balance was obtained due to the ultra-fine multiphase structure and high amount of stable retained austenite.
Evolution of Texture during Hot Rolling of a New Magnesium Alloy
Authors: Verma Krishna Kamlesh , Kumar Subodh , Suwas Satyam
Published: December 2018

High-strength wrought magnesium alloys are one of the sought-after materials in the automotive sector owing to the demands for weight reduction in the automobiles due to fuel economy and CO2 emission. However, because of low room temperature strength and formability of Mg alloys, only a few applications in wrought form have been explored with these materials. In the present investigation, a high strength, good ductility and low cost wrought magnesium alloy with Mg-Sn-Zn composition have been developed and subjected to conventional wrought processing. Hot rolling was carried out at 350°C without homogenization and after homogenization at 300°C and 330°C. The phase stability, microstructure and texture of the alloy has been investigated for as-cast, homogenized and hot rolled conditions. The compositional and microstructural characterization was carried out by Electron Probe Micro-analysis (EPMA) and optical microscopy respectively. Texture evolution was investigated by X-ray diffraction method. A strong (0002) basal texture develops after hot rolling without homogenization. The (0002) basal texture has been weekend by splitting of poles and double peak distribution when hot rolling was carried out after homogenization.
Effect of Sn Content on Heat Resistance of Mg-3%Al-1%Si Alloy for Casting
Authors: Saikawa Seiji , Mizutani Manabu , Kawabe Nozomu
Published: December 2018

Magnesium alloys have the characteristic with high specific strength and lightweight property, it is widely used for auto mobile industry. Heat-resistant magnesium alloy is focused as a suitable material for weight reduction of the engine and power train parts in automotive field. In this study, microstructure and heat-resistant property in Mg-3mass%Al-1mass%Si (Mg-3%Al-1%Si) alloy with containing large amount of Sn (tin) were investigated. The alloys produced by permanent mold casting were investigated by optical microscope (OM), scanning electron microscopy (SEM) and measuring of bolt load retention at 423K. The heat-resistant property of Mg-3mass % Al-1mass % Si alloy with containing 6-13masss%Sn was higher compared with Sn free alloy and conventional Magnesium alloys (e.g. AZ91 and AM60 alloys).