bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact of Chemical Fluctuations on Stacking Fault Energies of CrCoNi and CrMnFeCoNi High Entropy Alloys from First Principles
Authors: Ikeda Yuji , Körmann Fritz , Tanaka Isao , Neugebauer Jörg
Published: August 2018

Medium and high entropy alloys (MEAs and HEAs) based on 3d transition metals, such as face-centered cubic (fcc) CrCoNi and CrMnFeCoNi alloys, reveal remarkable mechanical properties. The stacking fault energy (SFE) is one of the key ingredients that controls the underlying deformation mechanism and hence the mechanical performance of materials. Previous experiments and simulations have therefore been devoted to determining the SFEs of various MEAs and HEAs. The impact of local chemical environment in the vicinity of the stacking faults is, however, still not fully understood. In this work, we investigate the impact of the compositional fluctuations in the vicinity of stacking faults for two prototype fcc MEAs and HEAs, namely CrCoNi and CrMnFeCoNi by employing first-principles calculations. Depending on the chemical composition close to the stacking fault, the intrinsic SFEs vary in the range of more than 150 mJ/m 2 for both the alloys, which indicates the presence of a strong driving force to promote particular types of chemical segregations towards the intrinsic stacking faults in MEAs and HEAs. Furthermore, the dependence of the intrinsic SFEs on local chemical fluctuations reveals a highly non-linear behavior, resulting in a non-trivial interplay of local chemical fluctuations and SFEs. This sheds new light on the importance of controlling chemical fluctuations via tuning, e.g., the annealing condition to obtain the desired mechanical properties for MEAs and HEAs.
Biology Education: The Value of Taking Student Concerns Seriously
Authors: Reiss Michael
Published: August 2018

This article examines the question of how biology courses can take student concerns more seriously than they often do. The focus is on school biology although the arguments apply to other biology courses too. The article begins by examining Michael Young’s argument that schools should provide students with access to powerful knowledge—the sort of knowledge that they are unlikely to obtain from elsewhere—and compares this with John White’s argument that the curriculum should enable student flourishing, and that as part of this, there should be more student choice about what they study. It then discusses recent work on the benefits of independent research projects, in which students undertake authentic investigative work where they have considerable control over the work, and concludes that these generally motivate students and are a good source of learning for them. It goes on to examine what lessons might be learnt for school biology from the informal learning sector, such as Natural History Museums, where visitors have great autonomy with regard to what they study. Finally, it looks at the concept of ‘worldviews’ and argues that this provides another argument for taking student concerns seriously. The article concludes that taking student concerns seriously in school biology would facilitate human development, in particular, development towards greater student autonomy, and that this can be done in ways that have been tried and allow for high quality biology teaching and learning.
Using Restorative Practices to Prepare Teachers to Meet the Needs of Young Adolescents
Authors: Silverman Jamie , Mee Molly
Published: August 2018

Recent news on school safety and efforts to improve school climate underscores the importance of building positive student relationships and resolving conflict in our nation’s classrooms. Restorative practices are currently gaining credibility and popularity as a means to build classroom and peer relationships. Through a descriptive study, we explored how to model the restorative practice of community circles with teacher candidates to prepare them to use the approach with their future middle school students. We describe how a teacher educator engaged middle-level teacher candidates with community circles in an internship seminar for this purpose. This article illustrates the powerful effects restorative practices had on the teacher candidates’ peer relationships and the connections they made about teaching young adolescent students. We also provide a step-by-step guide for implementing this practice in middle level teacher education programs.
Thermal 3D CFD Simulation with Active Transparent Façade in Buildings
Authors: Ramírez-Balas Cristina , Fernández-Nieto Enrique , Narbona-Reina Gladys , Sendra Juan José , Suárez Rafael
Published: August 2018

In recent years active façades have acquired greater importance given their capacity to improve the energy efficiency of buildings. One such type is the so-called Active Transparent Façade (ATF). A 3D numerical model based on computational fluid dynamics (CFD) and the Finite Element Method (FEM) has been generated to simulate the thermal performance of buildings equipped with this type of façade. This model is introduced for general application and allows the design parameters to be adapted for this system. The case study of Le Corbusier’s proposal for the City of Refuge in Paris, the clearest example of previous use of an ATF is examined. In addition, a proposal is presented for the energy improvement of Le Corbusier’s original solution. In order to do so, the conditions for the supply of air into the ATF cavity and in the mechanical ventilation system are assessed to guarantee comfort conditions.
Thermal Conductivity of Korean Compacted Bentonite Buffer Materials for a Nuclear Waste Repository
Authors: Yoon Seok , Cho WanHyoung , Lee Changsoo , Kim Geon-Young
Published: August 2018

Engineered barrier system (EBS) has been proposed for the disposal of high-level waste (HLW). An EBS is composed of a disposal canister with spent fuel, a buffer material, backfill material, and a near field rock mass. The buffer material is especially essential to guarantee the safe disposal of HLW, and plays the very important role of protecting the waste and canister against any external mechanical impact. The buffer material should also possess high thermal conductivity, to release as much decay heat as possible from the spent fuel. Its thermal conductivity is a crucial property since it determines the temperature retained from the decay heat of the spent fuel. Many studies have investigated the thermal conductivity of bentonite buffer materials and many types of soils. However, there has been little research or overall evaluation of the thermal conductivity of Korean Ca-type bentonite buffer materials. This paper investigated and analyzed the thermal conductivity of Korean Ca-type bentonite buffer materials produced in Gyeongju, and compared the results with various characteristics of Na-type bentonites, such as MX80 and Kunigel. Additionally, this paper suggests various predictive models to predict the thermal conductivity of Korean bentonite buffer materials considering various influential independent variables, and compared these with results for MX80 and Kunigel.
Study on the Characteristics of a High Capacity Nickel Manganese Cobalt Oxide (NMC) Lithium-Ion Battery—An Experimental Investigation
Authors: Zhang Ruifeng , Xia Bizhong , Li Baohua , Lai Yongzhi , Zheng Weiwei , Wang Huawen , Wang Wei , Wang Mingwang
Published: August 2018

The use of high-capacity batteries as the battery pack of electric vehicles is the current development trend. In order to better design battery packages and battery management systems and develop related battery estimation technology, the related characteristics of high capacity battery cells need to be studied in depth. Capacity and pulse tests of batteries at different temperatures are carried out in this paper. Through these experimental data, the electrical characteristics of different parameters of the high capacity battery, such as capacity characteristic data, internal resistance characteristic data, OCV-SOC characteristic relation curve, power data and temperature rise are analyzed. The specific parameters of the battery in the second order equivalent circuit model are obtained by using the off-line parameter identification method. These parameters results can be used as comparison data and reference data. It is beneficial to the on-line parameter identification of battery model and the estimation of battery state, so as to shorten the development time and improve the quality of the development.
Disturbance-Observer-Based Model Predictive Control for Battery Energy Storage System Modular Multilevel Converters
Authors: Liao Yantao , You Jun , Yang Jun , Wang Zuo , Jin Long
Published: August 2018

Although the traditional model predictive control (MPC) can theoretically provide AC current and circulating current control for modular multilevel converters (MMCs) in battery energy storage grid-connected systems, it suffers from stability problems due to the power quality of the power grid and model parameter mismatches. A two discrete-time disturbance observers (DOBs)-based MPC strategy is investigated in this paper to solve this problem. The first DOB is used to improve the AC current quality and the second enhances the stability of the circulating current control. The distortion and fluctuation of grid voltage and inductance parameter variation are considered as lump disturbances in the discrete modeling of a MMC. Based on the proposed method, the output prediction is compensated by disturbance estimation to correct the AC current and circulating current errors, which eventually achieve the expected tracking performance. Moreover, the DOBs have a quite low computational cost with minimum order and optimal performance properties. Since the designed DOBs work in parallel with the MPC, the control effect is improved greatly under harmonics, 3-phase unbalance, voltage sag, inductance parameter mismatches and power reversal conditions. Simulation results confirm the validity of the proposed scheme.
A Multi-Scale Conceptual Model of Flood-Tide Delta Morphodynamics in Micro-Tidal Estuaries
Authors: Austin Timothy P , Vila-Concejo Ana , Short Andrew D , Ranasinghe Roshanka
Published: August 2018

Wave and tide induced sediment transport pathways and rates govern the morphological evolution of estuarine systems. An understanding of the morphodynamics of these systems is required to maintain their commercial, biological and recreational value. The morphodynamics of Port Stephens estuary, a micro-tidal estuary located on a wave dominated southeast coast of Australia were investigated using bathymetric surveys and current velocity data from several locations over the estuary. This provided detailed insight into the rates and direction of movement for the main sedimentary features of the system, and how these features interact with the processes that drive their evolution. We used these findings to develop a conceptual model for estuarine morphodynamics that accounts for fair weather and storm conditions. Our model explains how sediment eroded from the estuarine beaches is trapped by the adjacent flood-tide delta. The model is applicable to fetch-limited estuaries that do not have offshore sources of sediment, where the tidal currents are weak in relation to the incident ocean waves, and that have a wide, stable entrance through which ocean waves can propagate into the estuary. The model is multi-scale in that it encapsulates both short-term and local process, and large scale evolution of an estuary; therefore, it represents a tool that may be used in developing sustainable estuary management strategies.
Optimal Timing to Trade along a Randomized Brownian Bridge
Authors: Leung Tim , Li Jiao , Li Xin
Published: August 2018

This paper studies an optimal trading problem that incorporates the trader’s market view on the terminal asset price distribution and uninformative noise embedded in the asset price dynamics. We model the underlying asset price evolution by an exponential randomized Brownian bridge (rBb) and consider various prior distributions for the random endpoint. We solve for the optimal strategies to sell a stock, call, or put, and analyze the associated delayed liquidation premia. We solve for the optimal trading strategies numerically and compare them across different prior beliefs. Among our results, we find that disconnected continuation/exercise regions arise when the trader prescribe a two-point discrete distribution and double exponential distribution.
Capturing Flood Risk Perception via Sketch Maps
Authors: Klonner Carolin , Usón Tomás J. , Marx Sabrina , Mocnik Franz-Benjamin , Höfle Bernhard
Published: August 2018

The fact that an increasing number of people and local authorities are affected by natural hazards, especially floods, highlights the necessity of adequate mitigation and preparedness within disaster management. Many governments, though, have only insufficient monetary or technological capacities. One possible approach to tackle these issues is the acquisition of information by sketch maps complemented by questionnaires, which allows to digitally capture flood risk perception. We investigate which factors influence information collected by sketch maps and questionnaires in case studies in an area prone to pluvial flooding in Santiago de Chile. Our aim is to gain more information about the methods applied. Hereby, we focus on the spatial acquisition scale of sketch maps and personal characteristics of the participants, for example, whether they live at this very location of the survey (residents) or are pedestrians passing by. Our results show that the choice of the acquisition scale of the base map influences the amount and level of detail of information captured via sketch maps. Thus, detail base maps lead to more precise results when compared to reference data, especially in the case of residents. The results also reveal that the place of living of the respondents has an effect on the resulting information because on the neighborhood level the risk perception of residents is more detailed than the one of pedestrians. The study suggests that the integration of citizens via sketch maps can provide information about flood risk perception, and thus can influence the flood mitigation in the area.
The Enhanced Interactive Physical and Cognitive Exercise System (iPACESTM v2.0): Pilot Clinical Trial of an In-Home iPad-Based Neuro-Exergame for Mild Cognitive Impairment (MCI)
Authors: Wall Kathryn , Stark Jessica , Schillaci Alexa , Saulnier Emilie T. , McLaren Elizabeth , Striegnitz Kristina , Cohen Brian D. , Arciero Paul J. , Kramer Arthur F. , Anderson-Hanley Cay
Published: August 2018

Given increasing longevity worldwide, older adults and caregivers are seeking ways to curb cognitive decline especially for those with mild cognitive impairment (MCI, now mild neurocognitive disorder, mNCD, Diagnostic and Statistical Manual of Mental Disorders, 5th ed. (DSM-V). This quasi-experimental, within-subjects pilot clinical trial was designed to replicate and extend the study of cognitive benefits for MCI by improving upon our prior interactive Physical and Cognitive Exercise Study (iPACESTM v1.0) by increasing the usability of the neuro-exergame and exploring possible underlying neurobiological mechanisms. Older adults were enrolled in a three-month, in-home trial of a portable neuro-exergame (iPACES™ v2.0) where participants pedaled and steered along a virtual bike path (Memory Lane™). Neuropsychological function was assessed at baseline after component familiarization intervals (e.g., two weeks of exercise-only, game-only, etc.) and after three months of interactive neuro-exergame intervention. Fourteen participants were enrolled in the study and seven completed the final evaluation. Intent-to-treat analyses were conducted with imputed missing data (total n = 14). Significant improvement in executive function (Stroop) was found (d = 0.68, p = 0.02) only. Changes in salivary biomarkers (cortisol and insulin-like growth factor 1; IGF-1) were significantly associated with improved cognition. Further research is needed, but pilot data suggest that a portable in-home neuro-exergame may be an additional, practical tool to fight back against cognitive decline and dementia.
Cognitive Frailty Predicts Incident Dementia among Community-Dwelling Older People
Authors: Shimada Hiroyuki , Doi Takehiko , Lee Sangyoon , Makizako Hyuma , Chen Liang-Kung , Arai Hidenori
Published: August 2018

Cognitive frailty, defined as the presence of both frailty and cognitive impairment, is a risk factor for adverse events in older adults. However, prevalence rates of cognitive frailty are low (1.1–2.5%), so primary screening is unsuitable in community settings. The aim of the study was to examine whether a new definition of cognitive frailty, which was developed for primary screening, is useful to predict incident dementia in community-dwelling older adults. A total of 4570 older adults participated in the study (2326 women; average age, 71.9 ± 5.5 years). We defined physical frailty as the presence of ≥1 of the following symptoms: slow walking speed and muscle weakness. Cognitive impairment was defined as ≥1 symptom of cognitive impairment, indicated by an age- and education-adjusted score that was ≥1.5 standard deviations below the reference threshold in word list memory, attention, executive function, and processing speed tests. Cognitive frailty was defined as comorbid physical frailty and cognitive impairment. The incidence of dementia was determined using data collected by the Japanese Health Insurance System over 36 months. The prevalence rates of physical frailty, cognitive impairment, and cognitive frailty were 17.5%, 15.3%, and 9.8%, respectively. Cognitive impairment (hazard ratio [HR]: 2.06, 95% confidence interval [95% CI]: 1.41–3.02) and cognitive frailty (HR: 3.43, 95% CI: 2.37–4.97) were found to be significant risk factors for dementia. However, the association between dementia and physical frailty was not significant (HR: 1.13, 95% CI: 0.76–1.69). Individuals with comorbid physical frailty and cognitive impairment could have a higher risk of dementia than healthy older adults or older adults with either physical frailty or cognitive impairment alone.
Effect of N/C Ratio on Precipitation Behavior of (Cr,Fe)23C6 Carbide in Novel Cast Austenitic Heat-Resistant Steels during Directional Solidification
Authors: Zhang Yinhui , Yang Jian
Published: August 2018

The precipitation of (Cr,Fe)23C6 carbide could significantly degrade the mechanical properties of Nb-bearing cast austenitic heat-resistant steels, designed for exhaust components of automotive gasoline engines at 1000 °C. In the current research, the precipitation behavior of (Cr,Fe)23C6 carbide in these alloys, with great variations in N/C (Nitrogen/Carbon) ratio, was investigated through the liquid metal cooling directional solidification method, combined with thermodynamic calculations. Microstructural characterization suggested that the (Cr,Fe)23C6 carbide formed in the steady-state zone and the competitive zone, upon cooling to room temperature, after the solidification ended. It grew in the colony of the δ-ferrite, through the eutectoid reaction and showed different concentrations of C and Si from the δ-ferrite. Its precipitation temperature decreased significantly with increasing the N/C ratio, thereby retarding its precipitation. Therefore, the quantity of (Cr,Fe)23C6 carbide could be limited though increasing the N/C ratio of this type of alloys.
Monitoring Aquaculture Water Quality: Design of an Early Warning Sensor with Aliivibrio fischeri and Predictive Models
Authors: Da Silva Luís F. B. A. , Yang Zhaochu , Pires Nuno M. M. , Dong Tao , Teien Hans-Christian , Storebakken Trond , Salbu Brit
Published: August 2018

A novel toxicity-warning sensor for water quality monitoring in recirculating aquaculture systems (RAS) is presented. The design of the sensor system mainly comprises a whole-cell biosensor. Aliivibrio fischeri, a luminescent bacterium widely used in toxicity analysis, was tested for a mixture of known fish-health stressors, namely nitrite, un-ionized ammonia, copper, aluminum and zinc. Two toxicity predictive models were constructed. Correlation, root mean squared error, relative error and toxic behavior were analyzed. The linear concentration addition (LCA) model was found suitable to ally with a machine learning algorithm for prediction of toxic events, thanks to additive behavior near the limit concentrations for these stressors, with a root-mean-squared error (RMSE) of 0.0623, and a mean absolute error of 4%. The model was proved to have a smaller relative deviation than other methods described in the literature. Moreover, the design of a novel microfluidic chip for toxicity testing is also proposed, which is to be integrated in a fluidic system that functions as a bypass of the RAS tank to enable near-real time monitoring. This chip was tested with simulated samples of RAS water spiked with zinc, with an EC50 of 6,46E-7 M. Future work will be extended to the analysis of other stressors with the novel chip.
An Intelligent Computing Method for Contact Plan Design in the Multi-Layer Spatial Node-Based Internet of Things
Authors: Dai Cui-Qin , Song Qingyang , Guo Lei
Published: August 2018

Computational Intelligence (CI) has been addressed as a great challenge in recent years, particularly the aspects of routing, task scheduling, and other high-complexity issues. Especially for the Contact Plan Design (CPD) that schedules contacts in dynamic and resource-constrained networks, a suitable CI algorithm can be exchanged for a high-quality Contact Plan (CP) with the appropriate computational overhead. Previous works on CPD mainly focused on the optimization of satellite network connectivity, but most of them ignored network topology characteristics. In this paper, we study the CPD issue in the spatial node based Internet of Things (IoT), which enables the spatial nodes to deliver data cooperatively via intelligent networking. Specifically, we first introduce a Multi-Layer Space Communication Network (MLSCN) model consisting of satellites, High Altitude Platforms (HAPs), Unmanned Aerial Vehicles (UAVs), and ground stations, on which a Time-Evolving Graph (TEG) is used to illustrate the CPD process. Then, according to the characteristics of each layer in the MLSCN, we design the corresponding CPs for the inter-layer contacts and intra-layer contacts. After that, a CI algorithm named as Multidirectional Particle Swarm Optimization (MPSO) is proposed for inter-layer CPD, which utilizes a grid-based initialization strategy to expand the diversity of individuals, in which a quaternary search method and quaternary optimization are introduced to improve efficiency of particle swarms in iterations and to ensure the continuous search ability, respectively. Furthermore, an optimized scheme is implemented for the intra-layer CPD to reduce congestion and improve transmission efficiency. Simulation results show that the proposed CPD scheme can realize massive data transmission with high efficiency in the multi-layer spatial node-based IoT.
Energy-Efficient Power Allocation and Relay Selection Schemes for Relay-Assisted D2D Communications in 5G Wireless Networks
Authors: Rahman Md Arifur , Lee YoungDoo , Koo Insoo
Published: August 2018

Device-to-device (D2D) communications allows user equipment (UE) that are in close proximity to communicate with each other directly without using a base station. Relay-assisted D2D (RA-D2D) communications in 5G networks can be applied to support long-distance users and to improve energy efficiency (EE) of the networks. In this paper, we first establish a multi-relay system model where the D2D UEs can communicate with each other by reusing only one cellular uplink resource. Then, we apply an adaptive neuro-fuzzy inference system (ANFIS) architecture to select the best D2D relay to forward D2D source information to the expected D2D destination. Efficient power allocation (PA) in the D2D source and the D2D relay are critical problems for operating such networks, since the data rate of the cellular uplink and the maximum transmission power of the system need to be satisfied. As is known, 5G wireless networks also aim for low energy consumption to better implement the Internet of Things (IoT). Consequently, in this paper, we also formulate a problem to find the optimal solutions for PA of the D2D source and the D2D relay in terms of maximizing the EE of RA-D2D communications to support applications in the emerging IoT. To solve the PA problems of RA-D2D communications, a particle swarm optimization algorithm is employed to maximize the EE of the RA-D2D communications while satisfying the transmission power constraints of the D2D users, minimum data rate of cellular uplink, and minimum signal-to-interference-plus-noise-ratio requirements of the D2D users. Simulation results reveal that the proposed relay selection and PA methods significantly improve EE more than existing schemes.
The Future of Influenza Vaccines: A Historical and Clinical Perspective
Authors: Bouvier Nicole M.
Published: August 2018

For centuries, the development of vaccines to prevent infectious disease was an empirical process. From smallpox variolation in Song dynasty China, through the polysaccharide capsule vaccines developed in the 1970s, vaccines were made either from the pathogen itself, treated in some way to render it attenuated or non-infectious, or from a closely related non-pathogenic strain. In recent decades, new scientific knowledge and technologies have enabled rational vaccine design in a way that was unimaginable before. However, vaccines optimal against some infectious diseases, influenza among them, have remained elusive. This review will highlight the challenges that influenza viruses pose for rational vaccine design. In particular, it will consider the clinically beneficial endpoints, beyond complete sterilizing immunity, that have been achieved with vaccines against other infectious diseases, as well as the barriers to achieving similar success against influenza.
Therapeutic Efficacy of Vitamin D in Experimental c-MET‐β-Catenin-Driven Hepatocellular Cancer
Authors: Matsuda Akiko , Ishiguro Kaori , Yan Irene K. , Patel Tushar
Published: August 2018

Aberrant activation of β-catenin signaling is frequently observed in hepatocellular cancer. Although Wnt/β-catenin signaling can be targeted by vitamin D, therapeutic use of vitamin D for this purpose is not currently established. We evaluated the therapeutic use of vitamin
D or its analogs using a synthetic transgenic mouse of hepatocarcinogenesis induced by mutant β-catenin, and MET overexpression in which 75% of mice develop well-differentiated HCC within 8 weeks in the absence of fibrosis. Vitamin D receptor expression was similar in both tumoral and
nontumoral tissue. There was no significant difference in overall survival, or in tumor progression assessed by imaging, biochemical, or tumor cell burden assessments in mice receiving a vitamin D-supplemented diet containing 12.0 IU VD/g (HVD) compared with a standard diet (SD) containing
2.3 IU VD/g. Furthermore, systemic treatment with calcitriol [vitamin D analog 1α,25(OH)2D3] or EB1089 (synthetic vitamin D analog) by intraperitoneal injection for 4 weeks prolonged median survival but did not increase overall survival compared with controls. Although
tumor formation was delayed in males compared with that in females, there was no difference in overall survival between males and females. In conclusion, although 1α,25(OH)2D3 is reported to inhibit β-catenin signaling, as well as proliferation, migration,
and differentiation in cancer cells, neither dietary supplementation with vitamin D nor treatment with vitamin D analogs altered the formation or growth of HCC associated with β-catenin activation. These results conclusively demonstrate the lack of utility of targeting vitamin D for therapy
of HCC in this setting.
Magnetism and magnetoresistance of single Ni–Cu alloy nanowires
Authors: Costas Andreea , Florica Camelia , Matei Elena , Toimil-Molares Maria Eugenia , Stavarache Ionel , Kuncser Andrei , Kuncser Victor , Enculescu Ionut
Published: August 2018

Arrays of magnetic Ni–Cu alloy nanowires with different compositions were prepared by a template-replication technique using electrochemical deposition into polycarbonate nanoporous membranes. Photolithography was employed for obtaining interdigitated metallic electrode systems of Ti/Au onto SiO2/Si substrates and subsequent electron beam lithography was used for contacting single nanowires in order to investigate their galvano-magnetic properties. The results of the magnetoresistance measurements made on single Ni–Cu alloy nanowires of different compositions have been reported and discussed in detail. A direct methodology for transforming the magnetoresistance data into the corresponding magnetic hysteresis loops was proposed, opening new possibilities for an easy magnetic investigation of single magnetic nanowires in the peculiar cases of Stoner–Wohlfarth-like magnetization reversal mechanisms. The magnetic parameters of single Ni–Cu nanowires of different Ni content have been estimated and discussed by the interpretation of the as derived magnetic hysteresis loops via micromagnetic modeling. It has been theoretically proven that the proposed methodology can be applied over a large range of nanowire diameters if the measurement geometry is suitably chosen.
Multiwavelength Light Curves of Two Remarkable Sagittarius A* Flares
Authors: Fazio G. G. , Hora J. L. , Witzel G. , Willner S. P. , Ashby M. L. N. , Baganoff F. , Becklin E. , Carey S. , Haggard D. , Gammie C. , Ghez A. , Gurwell M. A. , Ingalls J. , Marrone D. , Morris M. R. , Smith H. A.
Published: August 2018

Sgr A*, the supermassive black hole (SMBH) at the center of our Milky Way Galaxy, is known to be a variable source of X-ray, near-infrared (NIR), and submillimeter radiation and therefore a prime candidate to study the electromagnetic radiation generated by mass accretion flow onto a black hole and/or a related jet. Disentangling the power source and emission mechanisms of this variability is a central challenge to our understanding of accretion flows around SMBHs. Simultaneous multiwavelength observations of the flux variations and their time correlations can play an important role in obtaining a better understanding of possible emission mechanisms and their origin. This paper presents observations of two flares that both apparently violate the previously established patterns in the relative timing of submillimeter/NIR/X-ray flares from Sgr A*. One of these events provides the first evidence of coeval structure between NIR and submillimeter flux increases, while the second event is the first example of the sequence of submillimeter/X-ray/NIR flux increases all occurring within ∼1 hr. Each of these two events appears to upend assumptions that have been the basis of some analytic models of flaring in Sgr A*. However, it cannot be ruled out that these events, even though unusual, were just coincidental. These observations demonstrate that we do not fully understand the origin of the multiwavelength variability of Sgr A* and show that there is a continued and important need for long-term, coordinated, and precise multiwavelength observations of Sgr A* to characterize the full range of variability behavior.
ALMA Observations of Molecular Absorption in the Gravitational Lens PMN 0134−0931 at z = 0.7645
Authors: Wiklind Tommy , Combes Francoise , Kanekar Nissim
Published: August 2018

We report the detection of molecular absorption lines at z = 0.7645 toward the radio-loud quasi-stellar object (QSO) PMN 0134−0931. The CO J = 2–1 and HCO+
J = 2–1 lines are seen in absorption along two different lines of sight to lensed images of the background QSO. The lines of sight are separated by ∼0.″7, corresponding to 5 kpc in the lens plane. PMN 0134−0931 represents one out of only five known molecular absorption line systems at cosmologically significant distances. Moreover, it is also one of three such systems where the absorption occurs in a galaxy acting as a gravitational lens. The absorption lines through the two lines of sight are shifted by 215 ± 8 km s−1, possibly representing rotational motion in one of the lensing galaxies. The absorption profiles are wide, ∼200 km s−1, suggesting that the absorption occurs in a highly inclined disk galaxy with a flat rotation curve and a cloud–cloud velocity dispersion ∼30 km s−1. Gravitational lens models require two equal mass galaxies to account for the observed configuration of lensed images. The presence of two galaxies in close proximity means that they might be interacting and potentially merging and the kinematics of the molecular gas may not reflect ordered rotational motion. Compared with other high-redshift molecular absorption systems, the column densities of both CO and HCO+ are normal for diffuse molecular gas toward one of the lensed images, but significantly higher toward the other. Also, the abundance ratio

is 2 − 3 times higher than in typical diffuse molecular gas. It is plausible that the second line of sight probes denser molecular gas than what is normally the case for absorption.
Parametric Study of the Rossby Wave Instability in a Two-dimensional Barotropic Disk. II. Nonlinear Calculations
Authors: Ono Tomohiro , Muto Takayuki , Tomida Kengo , Zhu Zhaohuan
Published: August 2018

Vortices in protoplanetary disks have attracted attention since the discovery of lopsided structures. One of the possible mechanisms for producing vortices is the Rossby wave instability (RWI). In our previous work, we have performed detailed linear stability analyses of the RWI with various initial conditions. In this paper, we perform numerical simulations of the vortex formation by the RWI in two-dimensional barotropic disks using the Athena++ code. As initial conditions, we consider axisymmetric disks with a Gaussian surface density bump of various contrasts and half-widths. Perturbations grow as expected from the linear stability analyses in the linear and weakly nonlinear regimes. After the saturation, multiple vortices are formed in accordance with the most unstable azimuthal mode and coalesce one after another. In the end, only one quasi-stationary vortex (the RWI vortex) remains, which migrates inward. During the RWI evolution, the axisymmetric component approaches the stable configuration. We find that the axisymmetric component reaches the marginally stable state for the most unstable azimuthal mode at the saturation and for the m = 1 mode at the final vortex merger. We investigate the structure and evolution of the RWI vortices. We obtain some empirical relations between the properties of the RWI vortices and the initial conditions. Using tracer particle analyses, we find that the RWI vortex can be considered as a physical entity, like a large fluid particle. Our results provide solid theoretical ground for quantitative interpretation of the observed lopsided structures in protoplanetary disks.
Excitation of a Primordial Cold Asteroid Belt as an Outcome of Planetary Instability
Authors: Deienno Rogerio , Izidoro André , Morbidelli Alessandro , Gomes Rodney S. , Nesvorný David , Raymond Sean N.
Published: August 2018

The main asteroid belt (MB) is low in mass but dynamically excited. Here we propose a new mechanism to excite the MB during the giant planet (the “Nice model”) instability, which is expected to feature repeated close encounters between Jupiter and one or more ice giants (“jumping Jupiter” or JJ). We show that, when Jupiter temporarily reaches a high-enough level of excitation, both in eccentricity and inclination, it induces strong forced vectors of eccentricity and inclination across the MB region. Because during the JJ instability Jupiter’s orbit “jumps” around, the forced vectors keep changing both in magnitude and phase throughout the whole MB region. The entire cold primordial MB is thus excited as a natural outcome of the JJ instability. The level of such an excitation, however, is typically larger than the current orbital excitation observed in the MB. We show that the subsequent evolution of the solar system is capable of reshaping the resultant overexcited MB to its present-day orbital state, and that a strong mass depletion (∼90%) is associated with the JJ instability phase and its subsequent evolution throughout the age of the solar system.
Merger Rate Distribution of Primordial Black Hole Binaries
Authors: Chen Zu-Cheng , Huang Qing-Guo
Published: August 2018

Up to now several gravitational-wave events from the coalescences of black hole binaries have been reported by LIGO/VIRGO, and imply that black holes should have an extended mass function. We work out the merger rate distribution of primordial black hole (PBH) binaries with a general mass function by taking into account the torques by all PBHs and linear density perturbations. In the future, many more coalescences of black hole binaries are expected to be detected, and the one-dimensional and two-dimensional merger rate distributions will be crucial for reconstructing the mass function of PBHs.
Characterization and perspectives on studies of subterranean invertebrate communities in Latin America
Authors: Zepon Tamires , Bichuette Maria Elina
Published: August 2018

Studies about subterranean fauna in Latin America were intensified in the last decades. Many research are species description, but other knowledge areas have been studied, such as subterranean invertebrates communities. This study aims to characterize studies about these communities in Latin America countries. We made a bibliographic survey of published papers in scientific journals and bulletins of speleology groups, and different aspects were verified, like localities (country), publish date, number of sampled caves, use of tests and statistical analyzes and sample effort. Of the 20 Latin America countries, we not found those studies for ten (10) of them (Bolivia, Costa Rica, El Salvador, Haiti, Honduras, Nicaragua, Panama, Paraguay, Dominican Republic, and Uruguay). We accessed a total of 164 published studies, of which the most was conducted in Brazil (69), followed by Mexico (52), Venezuela (17) and Cuba (11). In Brazil, most of studies was published in the last two decades (2000-2017), in Mexico in the 70’s, in Venezuela between 80’s and 2009 and in Cuba in 70’s and 90’s. Except for Brazil, where the most of studies explored the influence of biotic and abiotic factors in the communities, all countries published mainly faunistic inventories about only an unique cave or region. Thus, they do not present tests and statistical analysis and, sometimes, neither ecological discussion. Moreover, many publications do not have information about number of sample occasions and most of Brazilian studies did only one sample occasion. That makes it harder both the ecological approach that permits the verification of patterns that acts in the communities structuring and the comparison of data from different regions. Therefore, although the knowledge of subterranean invertebrates communities has increased, the Latin American has a huge potential to be explored in relation to areas with few or no studies, and to more consistent ecological studies.
Redescription of Ventania avellanedae (Stylommatophora: Odontostomidae), a land snail endemic to the Ventania Mountain System, Argentina
Authors: Pizá Julia , Cazzaniga Néstor J. , Ghezzi Natalia S.
Published: August 2018

Although the presence of apertural folds and lamellae is the most recognizable character of the Odontostomidae, some species lack them, mostly inAnctusMartens, 1860,BahiensisJousseaume, 1877 andMoricandiaPilsbry & Vanatta, 1898.EudioptusavellanedaeDoering, 1881 – a slender odontostomid species that lacks even the slightest trace of folds or lamellae in its shell aperture – was however transferred toOdontostomusby Pilsbry in 1902 on the basis of its building forward of the aperture-margins. It is currently placed in its own monotypic subgenus, Cyclodontina (Ventania) Parodiz, 1940, on the basis of about the same argument. In this paper we redescribe its shell morphology and, for the first time, describe the internal anatomy of the pallial complex and the reproductive and digestive systems. The presence of a spongy gland in the pallial complex; of a short penis sheath with no retractor muscle; of a bursa copulatrix duct longer than spermoviduct, and of an epiphallic gland strongly support the inclusion of this unusual species in Odontostomidae. The species is diagnosable by the sculpture of the protoconch, which is not smooth as previously described, but has waved axial ribs crossed by spiral lines in young specimens; the distinctive external and internal shape of the bursa copulatrix duct; the internal penis wall divided in three regions of different sculpture; the smooth inner wall of the vagina; the long and cylindrical epiphallus with a distal widening indicating the presence of an epiphallic gland, and the penis retractor muscle inserted in the distal end of a short flagellum. These characters support the validity ofVentaniaParodiz, 1940, different fromCyclodontinaBeck, 1837.
La relación entre innovación y los procesos de planeación: Casos de estudio de empresas tecnológicas de la Zona Metropolitana de Guadalajara
Authors: Báez Francisco Ernesto Navarrete , Trejo Víctor Gabriel Sánchez
Published: August 2018

Cet article décrit la relation existante entre l’innovation et les processus de planification à l’intérieur des MPME dans la Zone métropolitaine de Guadalajara. Nous présentons les résultats obtenus grâce à l’analyse de 409 entreprises, ainsi que deux études de cas d’entreprises technologiques qui décrivent ces pratiques. L’analyse des résultats montre que les entreprises innovantes ont une corrélation positive entre la génération de nouveaux produits et la planification opérationnelle, ainsi qu’une relation négative entre l’innovation et la planification stratégique et la détermination des objectifs. De cette façon, la comparaison entre les deux types d’études permet de trouver une convergence entre la mise en œuvre de la planification opérationnelle dans la durabilité des PME.
Problemas en instrumentos y foros de Naciones Unidas orientados a promover la RSE en derechos humanos
Authors: Vargas-Laverde Jennyffer
Published: August 2018

Cet article établit les limites des principaux instruments et des scénarios qui guident la RSE en ce qui concerne les droits de l’homme sur l’analyse de leur concept et de la RSE ainsi que des obligations imposées par le droit international accepté pour la majorité des etats en Europe et en Amérique Latine. Plus précisément, il est conclu que ces instruments et les scénarios ont une vision restreinte qui ne comprennent pas les droits de l’homme comme universels, indivisibles et interdépendants, et qui considére le respect et la réparation des droits de l’homme comme un acte volontaire et de la responsabilité sociale des entreprises mais non obligatoires.
Aporte de la gestión socio-económica en la construcción de un lenguaje común en las pequeñas empresas internacionales
Authors: Dávila Andrés
Published: August 2018

Le but de cette recherche est de définir le concept de langage commun dans les petites entreprises internationales selon les principes du Management Socio-Économique. Cette recherche a eu lieu dans une petite entreprise internationale avec des filiales en Chine, France, Thaïlande et Viêt-Nam. Nous avons étudié le niveau de connaissance et de l’utilisation du langage commun au sein du groupe. Nos résultats nous permettent d’observer : a) l’impact du niveau hiérarchique sur sa connaissance et sur son utilisation et b) la nécessité de le formaliser par une terminologie commune afin de faciliter sa diffusion.
Animalité, humanité et paradigme technoscientifique
Authors: Bourg Dominique
Published: August 2018

Ce ne sont plus désormais quelques lanceurs d’alerte qui nous avertissent de la situation environnementale catastrophique qui échoit, mais maintenant des milliers de chercheurs et des centaines de publications. Et pourtant rien n’y fait, nous bougeons peu. Qui sommes-nous en tant qu’espèce pour qu’il en soit ainsi ? Telle est la première question que nous poserons et où il apparaîtra que nous ne méritons guère notre qualification de sapiens. Puis, nous nous interrogerons sur le type de civilisation qui autorise la destructivité que nous connaissons. Nous nous tournerons alors vers le « paradigme techno-scientifique » évoqué par l’encyclique Laudato si’.
Écologie profonde et spiritualité : un lien si fort
Authors: Charmetant Eric
Published: August 2018

La dimension spirituelle de l’écologie est souvent minimisée en se référant seulement à quelques voix de l’écologie radicale. Pourtant l’écologie profonde, par son regard aigu sur les interrelations entre les êtres vivants, est porteuse d’une spiritualité au sens fort définie par Hans Urs von Balthasar. À travers l’examen des pensées d’Arne Naess, Aldo Leopold, John Baird Callicott et Hans Jonas, nous dégagerons les valeurs fondamentales de l’écologie profonde et de sa spiritualité : décentrement, valeur des vies non humaines, responsabilité humaine asymétrique, injonction à des modes de vie durables. En cela, les spiritualités de l’écologie profonde peuvent être sources inspirantes pour vivre l’écologie intégrale de Laudato si’, même si elles ne lient qu’insuffisamment souci de la nature et souci des plus pauvres.
Pour une éthique de la sobriété
Authors: Laîné Loïc
Published: August 2018

Face à l’urgence et à la gravité de la crise écologique, le pape François dans l’encyclique Laudato si’ appelle à une véritable révolution culturelle. Il exhorte à la conversion écologique, qui suppose une remise en cause radicale de nos modes de vie. Sa proposition s’appuie sur une éthique de la sobriété, enracinée dans les ressources de la tradition et de la spiritualité chrétiennes. L’encyclique invite à redécouvrir une vertu un peu oubliée aujourd’hui, et à la vivre au plan personnel et au plan social. Elle propose également la sobriété comme principe d’organisation économique et social, pour inventer un autre modèle de croissance, plus juste et plus soutenable. La lecture de Laudato si’ nous conduit à proposer de formuler la sobriété parmi les principes permanents de la doctrine sociale.
Un exercice d’imagination théologique
Authors: Brison Sylvain
Published: August 2018

William Cavanaugh est devenu une des voies saillantes dans le débat contemporain sur le théologico-politique. En proposant la catégorie d’imagination théologique pour rendre compte des relations complexes entre l’Église et le monde, il donne une nouvelle manière d’envisager la question de la non-violence, non pas d’un point de vue pratique, exclusivement éthique, mais comme une structure essentielle de l’Église qui met en œuvre « la politique du Royaume des cieux ». Découvrir le conflit des imaginations résultant de la modernité, c’est, pour Cavanaugh, mettre à jour les fausses imaginations séculières qui portent la violence et commencer à vivre de l’imagination non violente du Royaume.
Violence et religions
Authors: Greiner Dominique
Published: August 2018

Pour certains, les religions sont intrinsèquement violentes ; pour d’autres, il n’y a aucun lien direct entre violence et religions. Mais ces deux perspectives radicalement opposées ont en commun d’être incapables d’envisager les traditions religieuses comme une ressource dans la lutte contre les violences commises en leur nom. Entre le déni de la violence d’origine religieuse et la désignation du fait religieux comme une pathologie sociale, la réflexion théologique offre une perspective plus réaliste. Pour le montrer, l’article prend appui sur une contribution récente de la Commission théologique internationale qui interprète le lien entre violence et religion à la lumière de la vérité christologique de Dieu, comme une marque de la corruption de l’expérience religieuse dont aucune tradition ne peut se dire protégée.