bluuebunny/crossref_metadata_2025 huggingface dataset:
Magnetar as Central Engine of Gamma-Ray Bursts: Quasi-universal Jet, Event Rate, and X-Ray Luminosity Function of Dipole Radiations
Authors: Xie Wen-Jin , Zou Le , Liu Hong-Bang , Wang Shan-Qin , Liang En-Wei
Published: May 2020

Early shallow-decaying X-ray afterglows of gamma-ray bursts (GRBs) may be attributed to the dipole radiations of newly born magnetars. Assuming that the GRB jets powered by magnetars are quasi-universal, we find that the jet structure can be parameterized as a uniform jet with a luminosity of

(1σ) and an opening angle

(50% confidence level), surrounding by a power-law decay component with an index of

(1σ). The inferred local GRB rate is ρ = 9.6 Gpc−3 yr−1 by including both the typical GRBs and LL-GRBs as the same population. The typical viewing angle is 3.3°, and may be 20° ∼ 30° for LL-GRBs. The X-ray luminosity function of the dipole radiation wind can be empirically described by a broken power-law function with indices

and

broken at

. In the case where the wind outflow is collimated and coaxial with the GRB jet, we find that the wind structure is similar to the GRB jet, i.e.,

,

, and

. The observed correlation between the prompt gamma-ray luminosity and X-ray luminosity of the wind may result from the viewing angle effect in such a jet–wind system. A discussion on surveys using the X-ray instruments on board the Einstein Probe mission in the soft X-ray band for the jet and wind emission is also presented.
Evidence for Proton Acceleration up to TeV Energies Based on VERITAS and Fermi-LAT Observations of the Cas A SNR
Authors: Abeysekara A. U. , Archer A. , Benbow W. , Bird R. , Brose R. , Buchovecky M. , Buckley J. H. , Chromey A. J. , Cui W. , Daniel M. K. , Das S. , Dwarkadas V. V. , Falcone A. , Feng Q. , Finley J. P. , Fortson L. , Gent A. , Gillanders G. H. , Giuri C. , Gueta O. , Hanna D. , Hassan T. , Hervet O. , Holder J. , Hughes G. , Humensky T. B. , Kaaret P. , Kar P. , Kelley-Hoskins N. , Kertzman M. , Kieda D. , Krause M. , Krennrich F. , Kumar S. , Lang M. J. , Maier G. , Moriarty P. , Mukherjee R. , Nievas-Rosillo M. , O’Brien S. , Ong R. A. , Park N. , Petrashyk A. , Pfrang K. , Pohl M. , Pueschel E. , Quinn J. , Ragan K. , Reynolds P. T. , Richards G. T. , Roache E. , Sadeh I. , Santander M. , Sembroski G. H. , Shahinyan K. , Sushch I. , Weinstein A. , Wilcox P. , Wilhelm A. , Williams D. A. , Williamson T. J , Zitzer B. , Ghiotto A.
Published: May 2020

We present a study of γ-ray emission from the core-collapse supernova remnant Cas A in the energy range from 0.1 GeV to 10 TeV. We used 65 hr of the Very Energetic Radiation Imaging Telescope Array System (VERITAS) data to cover 200 GeV–10 TeV, and 10.8 yr of Fermi-Large Area Telescope (LAT) data to cover 0.1–500 GeV. The spectral analysis of Fermi-LAT data shows a significant spectral curvature around 1.3 ± 0.4stat GeV that is consistent with the expected spectrum from pion decay. Above this energy, the joint spectrum from Fermi-LAT and VERITAS deviates significantly from a simple power law, and it is best described by a power law with a spectral index of 2.17 ± 0.02stat and a cutoff energy of 2.3 ± 0.5stat TeV. These results, along with radio, X-ray, and γ-ray data, are interpreted in the context of leptonic and hadronic models. Assuming a one-zone model, we exclude a purely leptonic scenario and conclude that proton acceleration up to at least 6 TeV is required to explain the observed γ-ray spectrum. From modeling of the entire multiwavelength spectrum, a minimum magnetic field inside the remnant of B
min ≈ 150 μG is deduced.
Discovery of Tidal Tails around the Old Open Cluster NGC 2506
Authors: Gao Xinhua
Published: May 2020

We report the discovery of tidal tails around the old open cluster NGC 2506 based on Gaia-DR2. A principal-component analysis and Gaussian mixture model are used to identify extra-tidal stars. We identify 2301 stars closely related to the cluster, 147 of which are likely extra-tidal stars. We find clear evidence for the existence of two well-defined tidal tails emerging from the cluster. The tidal tails extend out to projected distances of at least 54 pc, which is nearly three times as large as the tidal radius of the cluster. Furthermore, we find that the extra-tidal stars have a wide mass spectrum (∼0.6−1.4M⊙), which cannot be completely explained by mass segregation and the preferential evaporation of low-mass stars. An extra dynamical process such as disk-shocking may also play an important role in forming these extra-tidal stars. A mass-loss rate of ∼5.3M⊙Myr−1is estimated for the cluster. This reveals that NGC 2506 is currently undergoing heavy mass-loss due to star escapes.
Toward a Full MHD Jet Model of Spinning Black Holes. II. Kinematics and Application to the M87 Jet
Authors: Huang Lei , Pan Zhen , Yu Cong
Published: May 2020

In this paper, we investigate the magnetohydrodynamical structure of a jet powered by a spinning black hole, where electromagnetic fields and fluid motion are governed by the Grad–Shafranov equation and the Bernoulli equation, respectively. When a steady and axisymmetric jet structure is assumed, the global solution is uniquely determined with the prescribed plasma loading into the jet and the poloidal shape of the outmost magnetic field line. We apply this model to the jet in the center of the nearby radio galaxy M87, and we find that it can naturally explain the slow flow acceleration and the flow velocity stratification within 105 gravitational radii from the central black hole. In particular, we find that the extremal black hole spin is disfavored by the flow velocity measurements if the plasma loading into the jet is dominated by the electron-positron pair production at the jet base.
Energy Level Structure and Transition Data of Er2+
Authors: Gaigalas Gediminas , Rynkun Pavel , Radžiūtė Laima , Kato Daiji , Tanaka Masaomi , Jönsson P.
Published: May 2020

A majority of Er in the universe is synthesized by the r-process, which can occur in the mergers of neutron stars (NSs). The contribution of this element to the opacity of NS ejecta should be tested, but even the energy levels of first excited configuration have not been fully presented. The main aim of this paper is to present accurate energy levels of the ground [Xe]4f
12 and first excited [Xe]4f
115d configurations of Er2+. The energy level structure of the Er2+ ion was computed using the multiconfiguration Dirac–Hartree–Fock and relativistic configuration interaction (RCI) methods, as implemented in the GRASP2018 program package. The Breit interaction, self-energy, and vacuum polarization corrections were included in the RCI computations. The zero-first-order approach was used in the computations. Energy levels with the identification in LS coupling for all (399) states belonging to the [Xe]4f
12 and [Xe]4f
115d configurations are presented. Electric dipole (E1) transition data between the levels of these two configurations are computed. The accuracy of these data is evaluated by studying the behavior of the transition rates as functions of the gauge parameter, as well as by evaluating the cancellation factors. The core electron correlations were studied using different strategies. The rms deviations obtained in this study for states of the ground and excited configurations from the available experimental data are 649 and 754 cm−1, respectively.
Counterstreaming Strahls and Heat Flux Dropouts as Possible Signatures of Local Particle Acceleration in the Solar Wind
Authors: Khabarova O. , Zharkova V. , Xia Q. , Malandraki O. E.
Published: May 2020

Suprathermal electrons with energies of ∼70 eV and above are observed at 1 au as dispersionless halo electrons and magnetic field-aligned beams of strahls. For a long time, it has been thought that both populations originate only from the solar corona, and that the only active process impacting their properties in the solar wind is scattering. This view has consequently impacted the interpretation of typical patterns of pitch-angle distributions (PADs) of suprathermal electrons. Meanwhile, recent observational studies supported by numerical simulations have shown that there is an unaccounted population of electrons accelerated to suprathermal energies at reconnecting current sheets (RCSs) and 3D dynamical plasmoids (or 2D magnetic islands (MIs)) directly in the heliosphere. We present multispacecraft observations of counterstreaming strahls and heat flux dropouts in PADs within a region filled with plasmoids and RCSs unaffected by interplanetary shocks, comparing observed PAD features with those predicted by particle-in-cell simulations. We show typical PAD patterns determined by local acceleration of thermal-core electrons up to hundreds of electron volts. Resulting PAD views depend on properties and topology of particular RCSs, MIs, and plasma/magnetic field parameters. Our study suggests that solar wind-borne suprathermal electrons coexist with those of solar origin. Therefore, some of heat flux dropout and bidirectional strahl events can be explained by local dynamical processes involving magnetic reconnection. Possible implications of the results for the interpretation of the actively debated decrease in the strahl/halo relative density with heliocentric distance and puzzling features of suprathermal electrons observed at crossings of the heliospheric current sheet and cometary comas are also discussed.
The Search for MeV Electrons 2–45 au from the Sun with the Alice Instrument Microchannel Plate Detector Aboard New Horizons
Authors: Keeney B. A. , Versteeg M. , Parker J. Wm. , Stern S. A. , Brunts P. , Davis M. W. , Elliott H. A. , Ennico K. , Gladstone G. R. , McNutt R. L. , Olkin C. B. , Retherford K. D. , Singer K. N. , Spencer J. R. , Steffl A. J. , Weaver H. A. , Young L. A.
Published: May 2020

The Alice UV spectrograph aboard NASA’s New Horizons mission is sensitive to MeV electrons that penetrate the instrument’s thin aluminum housing and interact with its microchannel plate detector. We have searched for penetrating electrons at heliocentric distance of 2–45 au, finding no evidence of discrete events outside of the Jovian magnetosphere. However, we do find a gradual long-term increase in the Alice instrument’s global dark count rate at a rate of ∼1.5% per year, which may be caused by a heightened gamma-ray background from aging of the spacecraft’s radioisotope thermoelectric generator fuel. If this hypothesis is correct, then the Alice instrument’s global dark count rate should flatten and then decrease over the next 5–10 years.
Pharmacokinetics of Daclatasvir in Egyptian Adolescents with Genotype-4 HCV Infection
Authors: Al-Nahari Mogeb M , Abbassi Maggie M , Ebeid Fatma SE , Hassany Mohamed , El-Sayed Manal H , Farid Samar F
Published: May 2020

Background

Daclatasvir has potent antiviral activity against HCV infection when used in combination with sofosbuvir, however, its pharmacokinetics have not been described in adolescents. The aim is to determine the pharmacokinetic parameters of daclatasvir in adolescents, and to develop a population pharmacokinetic (PopPK) model.

Methods

Seventeen adolescent patients with genotype-4 chronic HCV infection received once daily oral daclatasvir 60 mg in combination with 400 mg sofosbuvir for 12 weeks. Steady state concentrations were determined. Non-compartmental and population PK were determined.

Results

The average PK parameters calculated by non-compartmental analysis (NCA): maximum plasma concentration (Cmax), area under the curve (AUC), apparent oral volume of distribution (V/F), apparent oral clearance (CL/F) and half-life (T1/2) were 1,092 ng/ml, 11,178 ng/ml•h, 55 l, 4.5 l/h and 8.5 h, respectively. Daclatasvir was best described by one compartment structural PK model with zero order absorption and first-order elimination. The absorption rate constant (K0), V/F, and CL/F of the final PopPK model of daclatasvir were 1.5/h, 52 l and 4.7 l/h, respectively. Body weight and serum albumin had significant effect on the V/F parameter.

Conclusions

Body weight and serum albumin were the major determinants of daclatasvir V/F in this population. PK parameters were comparable to those reported in adult HCV patients, demonstrating that 60 mg daclatasvir is an appropriate dose for adolescents. ClinicalTrials.gov NCT03540212.
Georeferencing the Natural History Museum's Chinese type collection: of plateaus, pagodas and plants
Authors: Lohonya Krisztina , Livermore Laurence , Penn Malcolm
Published: May 2020

The digitising efforts of herbaria aim to increase access to and impact of scientific collections, by making the data digitally accessible to the global community. Digitising the NHMUK’s botanical collection of around 5.1 million specimens is an ongoing process, but the majority of the type collections have already been imaged. The Chinese type collection has also been transcribed; however, during the recent georeferencing process, we realised that much of the data had been transcribed incorrectly, particularly the locality information in which 80% of the collection contained errors. We discovered 154 specimens that were mistakenly filed in China. We corrected the mistakes from the previous transcription and georeferenced the collection which consists of 3,736 records. In this paper, we discuss the problems and errors we encountered during the georeferencing process, detailing why there were mistakes, what made the transcription harder than expected and what could have led to errors. We also give a short description about the Chinese language and its difference from European languages, leading to complex problems for georeferencing. We provide a brief guide on how to georeference a Chinese collection, avoiding errors and making the georeferencing process easier and faster.
Methods & Proposal for Metadata Guiding Principles for Scholarly Communications
Authors: Kaiser Kathryn , Kemp Jennifer , Paglione Laura , Ratner Howard , Schott David , Williams Helen
Published: May 2020

This article describes an international community-based effort to create metadata guiding principles for adopting and using richer metadata and advancing its application in scholarly communications. These principles can facilitate the dissemination, discoverability and use/reuse of many types of research and scholarly outputs. While much work remains to be done, these principles serve as a starting point for the evolution of processes that span communities including publishers, researchers, scholars, authors and other creators, librarians, curators, custodians, and consumers of scholarly works.

These aspirational Metadata 2020 Principles are designed to encompass the needs of our entire community while ensuring thoughtful, purposeful, and reusable metadata resources. They provide a framework for all of us to be good metadata citizens. They also provide a foundation for considering related work from Metadata 2020 and must be interpreted within the legal and practical context in which we operate. They are intended to guide the broadest possible cross-section of our community in improving research communications, publishing, and discoverability.
Rotatory role-playing and role-models to enhance the research integrity culture
Authors: Prieß-Buchheit Julia , Aro Arja , Demirova Iliyana , Lanzerath Dirk , Stoev Pavel , Wilder Nicolaus
Published: May 2020

The Path2Integrity project is a two-component coordination and support action to enhance research integrity cultures. Path2Integrity develops and fosters role-models and rotatory role-play scenarios for secondary school students, undergraduates, graduates, and early career researchers. A Path2Integrity campaign for scientific facts about research integrity and role-models, raises awareness of research integrity within secondary schools and universities. A complementary Path2Integrity handbook of instructions, which contains vivid stories involving research integrity and rotatory role-playing increases students’ ability to form judgements about the acceptance or rejection of norms in research. A train-the-trainer program shows how to use the Path2Integrity handbook of instructions, especially how to apply the handbook to the educators’ discipline and how to implement it into organisations. Partners from the Consortium have award-winning experience in creating those settings, which allows Path2Integrity to work with educational practices already in existence. Taking into account that different disciplines and different schools of thought are involved, it is the Consortium’s paramount concern, to ensure explicitly that the Path2Integrity handbook and campaign are based on optimal and systematic evidence-based decisions.
Description of Longidorus bordonensis sp. nov. from Portugal, with systematics and molecular phylogeny of the genus (Nematoda, Longidoridae)
Authors: Gutiérrez-Gutiérrez Carlos , Teixeira Santos Margarida , Inácio Maria Lurdes , Eisenback Jonathan D. , Mota Manuel
Published: May 2020

The genusLongidoruscurrently comprises 176 species of polyphagous plant ectoparasites, including eight species that vector nepoviruses.Longidorusis one of the most difficult genera to accurately identify species because of the similar morphology and overlapping measurements and ratios among species. Sequences of ribosomal RNA (rRNA)-genes are a powerful level-species diagnostic tool for the genusLongidorus. From 2015 to 2019, a nematode survey was conducted in vineyards and agro-forest environments in Portugal. The populations ofLongidorusspp. were characterized through an integrative approach based on morphological data and molecular phylogenetic analysis from rRNA genes (D2-D3 expansion segments of the 28S, ITS1, and partial 18S), including the topotype ofL. vinearum.Longidorus bordonensissp. nov., a didelphic species recovered from the rhizosphere of grasses, is described and illustrated.Longidorus vineacola, with cork oak and wild olive as hosts, is also characterized. This is the first time thatL. wicuolea, from cork oak, is reported for Portugal. Bayesian inference (BI) phylogenetic trees for these three molecular markers established phylogenetic relationships among the new species with otherLongidorusspp. Phylogenetic trees indicated that i)L. bordonensissp. nov.is clustered together with otherLongidorusspp. and forms a sister clade withL. piniandL. carpetanensis, sharing a short body and odontostyle length, and elongate to conical female tail, and ii) all the other species described and illustrated are phylogenetically associated, including the topotype isolate ofL. vinearum.
Hybrid HRM as a framework for handling cultural dominance issues at work
Authors: Nyobe Sara , Plane Jean-Michel
Published: May 2020

Cet article aborde un sujet inexploité en Management et en Gestion des Ressources Humaines (GRH) : la domination culturelle. Des téléopérateurs de centres d’appels étrangers doivent, à l’occasion de leur travail, s’assimiler à la culture de leurs clients occidentaux. Afin de limiter d’éventuelles contradictions entre cette culture imposée et leur culture originelle, ces téléopérateurs sont susceptibles de développer des stratégies identitaires individuelles. Peut-on imposer à des travailleurs tunisiens une identité occidentale ? Peut-on obtenir de salariés musulmans qu’ils adoptent le principe de laïcité à la française, ou encore des traditions judéo-chrétiennes ? A l’issue d’une étude empirique de 55 téléopérateurs et managers de deux centres d’appels tunisiens servant des multinationales françaises, nous révélons que la mise en œuvre de pratiques hybrides de GRH – considérant simultanément les attentes locales et globales – peut contribuer à l’acceptation par des salariés, d’une identité culturelle imposée. L’étude alimente la littérature internationale en GRH en mettant en évidence les conséquences potentielles de la domination culturelle sur des salariés. Elle propose par ailleurs un ensemble de pratiques hybrides de GRH permettant de gérer la domination culturelle. Elle montre enfin, l’intérêt théorique des modèles de l’hypocrisie organisationnelle et de l’organisation ambidextre pour décrypter des situations interculturelles complexes.
L’ancrage expérientiel de l’expertise managériale. Le cas d’un chef de mission de simulation d’exploration spatiale
Authors: Bonnet Emmanuel
Published: May 2020

Cet article questionne la possibilité de fonder l’expertise managériale sur l’expérience. L’ancrage expérientiel de l’expertise managériale ne va pas de soi. Si l’expérience vécue peut être considérée comme une source d’apprentissage, sa contribution à la construction de connaissances expertes en management semble beaucoup moins évidente. Certaines critiques ont mis en évidence une tendance idéologique à réifier le management dans un corpus de connaissances génériques qui ne tient pas compte des pratiques singulières. L’enjeu de cet article consiste moins à alimenter le contenu d’un tel corpus que d’appréhender l’expertise à partir d’un ancrage expérientiel. Une perspective pragmatiste est ici privilégiée pour aborder l’expertise comme une activité cognitive, incarnée et située. Notre terrain est la simulation d’une mission d’exploration martienne dans une station située dans le désert de l’Utah. Adoptant une démarche d’ethnographie organisationnelle, cet article se concentre sur la pratique du chef de mission. Cette pratique d’abord considérée comme énigmatique par l’équipage, compose avec un collectif qui se déploie selon différentes orientations. Les résultats permettent de rompre avec certaines idées tenues pour acquises concernant le contenu intrinsèque de l’expertise managériale et renforcent l’importance de la pluralité des manières de vivre une expérience pour l’accomplissement d’une action collective en situation d’exploration. Sur cette base, nous soulignons une approche alternative à l’apprentissage traditionnel du management.
Labellisation et pratiques des consultants en prévention des risques psychosociaux : de l’expert institutionnel à l’expert politique
Authors: Chakor Tarik
Published: May 2020

L’objectif de cet article est d’analyser un mode de labellisation des consultants en prévention des risques psychosociaux (RPS), et de le confronter aux pratiques effectives de ces nouvelles figures expertes. Champ de connaissances à la fois complexe et stratégique, les RPS font état d’un périmètre conceptuel et terminologique flou : ces risques peuvent faire l’objet d’une approche restrictive, tendant à individualiser le risque, limiter la responsabilité de l’employeur et soigner le travailleur d’une part ; et d’une approche élargie, appréhendant la dimension organisationnelle du risque, étendant la responsabilité de l’employeur et soignant le travail et son organisation d’autre part. Cette double lecture, combinée aux jeux de pouvoir et rapports de force entre employeurs et représentants du personnel et à l’hypermédiatisation de ces nouveaux risques professionnels (troubles musculo-squelettiques, burn-out , harcèlement, etc.), ont progressivement accordé une place centrale aux consultants externes, avec la constitution progressive d’un marché du conseil et de l’expertise en prévention des RPS. Notre étude exploratoire, menée au sein du réseau de consultants i3r PACA animé par un triptyque institutionnel (DIRECCTE, CARSAT, ARACT), nous a permis dans un premier temps d’étudier un mode de labellisation de consultants : la labellisation « i3r PACA », donnant naissance à l’expert institutionnel en RPS. Dans un second temps, nous avons interrogé 31 consultants de ce réseau (sur 33) autour de leurs pratiques de prévention co-constructives, adaptatives et/ou militantes, qui font émerger la figure de l’expert politique. Notre discussion s’attachera à interroger les nouvelles formes hybrides entre expert institutionnel et expert politique, notamment au regard de la marchandisation du conseil et de l’expertise en RPS.
La sensibilité, vecteur de l’expertise : le cas des joueurs de volley-ball
Authors: Récopé Michel , Fache Hélène , Rix-Lièvre Géraldine
Published: May 2020

Notre contribution, adossée à des recherches conduites en raison d’insatisfactions issues du terrain de la formation en volley-ball, s’efforce d’investir un aspect méconnu favorisant l’accès à l’expertise. Elle s’inscrit dans les prolongements récents de l’approche énactive et de la philosophie de la vie, des normes et des valeurs de Canguilhem. Nous étudions l’activité de deux volleyeurs experts au moyen d’observations systématiques et d’entretiens d’autoconfrontation. La confrontation des matériaux comportementaux et des verbatim met en évidence une cohérence propre commune aux deux joueurs, mais également à certains novices, ceux précisément qui performent et progressent davantage que les autres. Les résultats suggèrent que la sensibilité à est, au fondement de cette cohérence, un vecteur crucial de l’expertise. Elle est l’entité intégrant affectivité, cognition et motricité, ainsi que l’instance de la mobilisation de la personne vers ce qui lui importe. Les experts et certains novices ont une sensibilité à commune et nous détaillons les raisons pour lesquelles celle-ci favorise l’accès à l’expertise. L’expert et le novice ne doivent plus être considérés comme des opposés, car leur activité peut être orientée par une même sensibilité à ; il y a lieu de distinguer et de relier deux axes d’analyse : celui de la sensibilité et celui de l’expertise. Nous défendons le principe que mieux comprendre l’expertise, c’est comprendre les conditions qui la favorisent pour tenter de concevoir une formation visant son accès.
Schizoaffective Disorder: Treatment Considerations
Authors: Schnitzer Kristina , Beckmann David , Freudenreich Oliver
Published: May 2020

Rigorous studies of treatment efficacy in schizoaffective disorder have been limited by the diagnosis' low diagnostic validity and reliability; thus, no current consensus treatment guidelines exist. Given this limitation, the authors recommend using available data from clinical trials in the mood disorder and psychosis literature to guide clinical practice. Antipsychotic treatment remains the mainstay of pharmacotherapy for illnesses on the schizophrenia spectrum, which includes schizoaffective disorder, both the depressive and bipolar subtypes. For patients with schizoaffective disorder, depressive type, treatment with combination antipsychotic and antidepressant therapy is a reasonable therapeutic starting point. For patients with schizoaffective disorder, bipolar type, antidepressant therapy may be less helpful. Instead, mood stabilizers may be an important component of treatment for people with schizoaffective disorder, bipolar type, particularly if there is irritability or aggression; some mood stabilizers, particularly lithium, may be effective in treating the depressive subtype as well.

[
Psychiatr Ann
. 2020;50(5):200–204.]
Classification of Schizoaffective Disorder: The History of a Vexing Concept
Authors: Freudenreich Oliver , Kontos Nicholas , Querques John
Published: May 2020

Schizoaffective disorder, which straddles schizophrenia and mood disorders, is a problem for our diagnostic classification system. Its validity as a unique disorder independent from schizophrenia and affective illnesses has not been established, and its reliability in routine clinical care is poor. However, it clearly fills a gap in our nomenclature, particularly for good-prognosis schizophrenia-like cases that remit like mood disorders do. In this article, we provide some historical and conceptual background to help clinicians understand the epistemological challenges of the diagnosis of schizoaffective disorder.

[
Psychiatr Ann
. 2020;50(5):186–189.]
Group lending, matching patterns, and the mystery of microcredit: Evidence from Thailand
Authors: Ahlin Christian
Published: May 2020

How has the microcredit movement managed to push financial frontiers? Theory shows that if borrowers vary in unobservable risk, then group‐based, joint liability contracts price for risk more accurately than individual contracts, provided that borrowers match with others of similar project riskiness (Ghatak (1999, 2000)). This more accurate risk‐pricing can attract safer borrowers and rouse an otherwise dormant credit market. We extend the theory to include correlated risk, and show that borrowers will match with partners exposed to similar shocks to lower their chances of facing liability for their partners. We use unique data on Thai microcredit borrowing groups to test for homogeneous matching by project riskiness and type of risk exposure. Evidence supports the theory, in that groups are more homogeneous in riskiness but less diversified in type of risk exposure than they would be under random matching. The results suggest that group lending is improving risk‐pricing by embedding a discount for safe borrowers, and can thus explain part of the unprecedented rise in financial intermediation among the world's poor; but that a potential pitfall of voluntary group formation is antidiversification, which points to strategies for lender intervention.
Identifying the discount factor in dynamic discrete choice models
Authors: Abbring Jaap H. , Daljord Øystein
Published: May 2020

Empirical research often cites observed choice responses to variation that shifts expected discounted future utilities, but not current utilities, as an intuitive source of information on time preferences. We study the identification of dynamic discrete choice models under such economically motivated exclusion restrictions on primitive utilities. We show that each exclusion restriction leads to an easily interpretable moment condition with the discount factor as the only unknown parameter. The identified set of discount factors that solves this condition is finite, but not necessarily a singleton. Consequently, in contrast to common intuition, an exclusion restriction does not in general give point identification. Finally, we show that exclusion restrictions have nontrivial empirical content: The implied moment conditions impose restrictions on choices that are absent from the unconstrained model.
Household portfolios and financial preparedness for retirement
Authors: Crawford Rowena , O'Dea Cormac
Published: May 2020

Using a lifecycle model of consumption, saving and portfolio choice combined with linked survey and administrative data on wealth and lifetime earnings we evaluate measures of retirement preparedness. We estimate heterogeneous discount factors for households and compare these estimates of their patience to their replacement rates—the simple measure often used to evaluate the adequacy of retirement savings. We find first that the specification of the model's asset structure matters quantitatively for preference parameter estimates—households appear to be much more patient when they are assumed to have access only to a risk‐free asset compared to when we account for the fact that much of their wealth is stored in higher‐return tax‐advantaged private pensions and in housing. Second, we find that only the most patient households achieve the replacement rates out offinalearnings that are often recommended by policymakers and industry as sensible benchmarks for retirement preparedness. Notwithstanding this, we find that even quite impatient households in the population we study achieve high replacement rates out of lifetimeaverageincome—a more sensible summary measure of preparedness for retirement.
Atom Motion in Solids Following Nuclear Transmutation
Authors: Collins Gary Scott
Published: May 2020

Following nuclear decay, a daughter atom in a solid will "stay in place" if the recoil energy is less than the threshold for displacement. At high temperature, it may subsequently undergo long-range diffusion or some other kind of atomic motion. In this paper, motion of 111Cd tracer probe atoms is reconsidered following electron-capture decay of 111In in the series of In3R phases (R= rare-earth). The motion produces nuclear relaxation that was measured using the method of perturbed angular correlation. Previous measurements along the entire series of In3R phases appeared to show a crossover between two diffusional regimes. While relaxation for R= Lu-Tb is consistent with a simple vacancy diffusion mechanism, relaxation for R= Nd-La is not. More recent measurements in Pd3R phases demonstrate that the site-preference of the parent In-probe changes along the series and suggests that the same behavior occurs for daughter Cd-probes. The anomalous motion observed for R= Nd-La is attributed to "lanthanide expansion" occurring towards La end-member phases. For In3La, the Cd-tracer is found to jump away from its original location on the In-sublattice in an extremely short time, of order 0.5 ns at 1000 K and 1.2 ms at room temperature, a residence time too short to be consistent with defect-mediated diffusion. Several scenarios that can explain the relaxation are presented based on the hypothesis that daughter Cd-probes first jump to neighboring interstitial sites and then are either trapped and immobilized, undergo long-range diffusion, or persist in a localized motion in a cage.
Evaluation of Recycled Aggregate (RAP) Presence Impact under Indirect Tensile Strength of Bitumen Stabilized Mix with Foamed Asphalt for a Base Layer
Authors: Guzmán Marcos Ariel Villanueva , Alamilla Horacio Delgado , Guzmán Elia Mercedes Alonso , Molina Wilfrido Martínez , Chávez-García Hugo Luis , Ruiz Rosalía Ruiz
Published: May 2020

Foamed bitumen improves the properties of base layer, increasing the number of equivalent axles allowed, as result of this is a durable pavement. To achieve this, base layer’s design must count with an amount of filler, to increase the stony aggregate fraction. This research consists with two different types of filler, lime and cement, 1% in dosage respect to the stony aggregate weight. Has been discovered now, that the RAP (reclaimed asphalt pavement) aggregate in addition to mitigate environmental problems, has a significant impact value on the mechanic resistance of the mix.
Mechanical Properties of Concrete Using Treated Recycled Concrete Aggregate in Marine Environment
Authors: Ismail Sallehan , Ramli Mahyuddin
Published: May 2020

This study also investigates the effectiveness of multiple surface modification of recycled concrete aggregate (RCA) with respect to mechanical properties of the resultant recycled aggregate concrete (RAC) when exposed to various curing conditions, namely, normal water (Nw) and seawater (Sw). The properties included compressive and flexural strength and impact resistance. Findings show that effect inclusion of the treated coarse RCA is significant in enhancing the mechanical properties of RAC. The exposure to Sw appears to affect the degradation of the compressive strength of RAC remarkably in a marine environment. In this case, however, using of treated RCA is found beneficial in decreasing the deterioration in the compressive strength of RAC.
Mechanical and Shrinkage Behaviors of Ductile Fiber-Reinforced Polymer Repair Mortar
Authors: Han Gu Yue , Luo Jian Lin
Published: May 2020

Repair mortar (RM) with dense texture and high anti-crack is cost-effective for application onto the surface of concrete structure to effectively delay the detachment of concrete protective layer and the corrosion of steel bars. Here, the effects of ductile fiber and polymer latex on the flexural strength (ft), compressive strength (fc), bond strength (fb), and shrinkage rate (δr) of fiber-reinforced polymer repair mortar (FP-RM) were comprehensively studied. Results show, the individual doping of polymer latex can improve the ft, fb, and the toughness (the ft/fc ratio) of P-RM, and the fb is increased by 75.78% with respect to the plain mortar, which imply polymer ingredient is essential to P-RM. Some ductile fibers individual dosage also can enhance the ft, fc, and δr of F-RM, respectively; When the polymer latex and ductile fiber are simultaneously doped into the FP-RM mortar together, the ft and fb of FP-RM can be increased up to 9.4MPa, and 2.52MPa, respectively, in tandem with 40.54% reduction of δr, showing superior synergy effect.
Experimental Investigation and Modelling of Claystone from Mae Moh Coal Mine, Thailand
Authors: Wongchana Pongsakorn , Jitsangiam Peerapong
Published: May 2020

The open pit mine is excavation soil from the Earth's surface, leading to presence of cut steep slopes with stability-concerned manners. Mae Moh open pit mine has the main component of claystone with ambiguous properties under stress condition changes from mine operations. Therefore, the strength of the claystone must be studied to be used for the slope stability analysis. Shear strength parameters for slope stability analysis were derived from the Triaxial Compression tests. Claystone is a type of sedimentary rock. Therefore, it is necessary to improve the equipment of the triaxial compression strength test to fit with intrinsic soft rock characteristics of the Mae Moh Claystone. Determination of parameters was based on Mohr Coulomb model, because it is the basis for slope stability analysis and can be resulted from the triaxial compression test. In addition, many computer-based programs for slope stability analysis also were relied onthe Mohr Coulomb model, including PLAXIS used in this study. Before the analysis, the model were validated by the function of “Simulation of Lab Test” in PLAXIS. Comparison on triaxial compression test results between the Mohr-Coulomb Model from PLAXIS and triaxial compression tests were made. This article reported the strength characteristics of Mae Moh claystone.
Response Behavior of Local Surface Failure due to Repetitive Impact of Stainless Steel
Authors: Sukpat Mahathep , Tuchinda Karuna
Published: May 2020

Material property that can describe its behavior under repetitive impact is an important data for the design and failure analysis of any engineering part. Study of this behavior by measuring the size of apparent damaged area at the surface (crater depth) and tracking the damage intensity is extremely difficult for small area. An attempt to develop the understanding of different response behavior during repetitive impact of stainless steel was made in this work. This paper presented the relation of the response signal to the contact surface condition in the repetitive impact test by mean of spectrum analysis. Acceleration response of a specimen under impact load could be affected by contact condition since contact area and local thickness of the specimen could be changed. The testing machine was developed to provide the repetitive impact force to the specimen. Surface morphology and depth of the crater were captured by optical microscope and 2D-stylus profilometer. The appearance in the peak spectrum amplitude of a response signal was found to be a noticeable response behavior that can differentiate the damaged specimen from the healthy specimen. Results of the response spectrum gave a clear relation to the damage intensity of the specimen. The increase in the peak amplitude during the number of impact cycles was found in the damaged specimen while the non-damaged specimen conditions the peak amplitude of the response is constant throughout the test.
High Purity Lime as an Ecologic Alternative for Construction Mortars and Pastes
Authors: Navarro-Mendoza Elena Guadalupe , Bedolla-Arroyo Juan Alberto , Sánchez-Calvillo Adrià , Guzmán Elia Mercedes Alonso , Blancas-Herrera Victor Hugo , Molina Wilfrido Martínez , Chávez-García Hugo Luis
Published: May 2020

Limestone is one of the most ancient construction materials that exist, however it has become obsolete over the last decades, being replaced by industrial materials like cement. It must be considered that not only the construction lime can be used in works, but the limestone industry can provide other products like high purity lies The research about the surface area of high purity lime has verified that it exists an improvement in the adhesion and workability features of the material in comparison with construction lime, besides to be a more economical solution than masonry cement. It is proposed in this document the use of high purity lime in construction works to achieve the benefits previously mentioned. Various samples with different percentages of high purity limes were tested in the laboratory, analysing the surface area changes between them, considering its use for construction purposes and its performance.
The Effect of Alloying on the Fractional Composition, Shape and Grain Size Distribution of the Structure Alloy GAP the Fe-Nd-B System
Authors: Chaika Victoriia A. , Savin Valeriy V. , Sorokovikov Mikhail , Marikhin Artem
Published: May 2020

The magnetic and mechanical properties of the magnets Fe-Nd-B system are more dependent on the size and shape of the grain structure. The authors explored the effect of the neodymium content and the addition of transition metals (Mo, Co, Al) and rare-earth metals (Dy, Tb) on the formation of the structure alloy gas atomization powder the Fe-Nd-B system. It has been shown that doping enhances the formation of grain blocks with a radial gradient in the direction of grain growth. The alloying of a gas atomization powder alloy of the Fe-Nd-B system with rare-earth metals increases the anisotropy of the grain shape.
Fabrication Study of Cu-C-Ni for EDM Electrode by a Sintering Technique
Authors: Janmanee Pichai , Muttamara Apiwat , Saodaen Rattikorn , Rodchanarowan Aphichart
Published: May 2020

The aim of this research was to study the feasibility for applications related to powder metallurgy in EDM electrode fabrication by combination of the percentage Cu-C-Ni element. The experiment was performed by comparing preliminary distribution results of particle size before and after the grinding of metal powders. The work-piece was pressed at a pressure of 200 Psi using a uniaxial press machine. The pressed green compact work-piece was then baked in a furnace. The gas inside the furnace that was used to control the temperature during the cold press procedure had a mixture gas ratio between argon and hydrogen of 95:5 (common grade) at 1030 oC and a soaking time of one hour. The results were examined by comparing the electric resistivity property, apparent density, bulk density as well as the porosity percentage inside the work piece material. The results revealed that the optimum combination of percentage Cu-C-Ni element was Cu92-C3-Ni5 (%wt), leading to the satisfactory Copper distribution in most of the structure. The size of sub sieve powder after grinding was found to be 22-31 micron with an electric resistivity of 1.45829E-05 k-ohm*cm. The minimum porosity percentage was found to be 2.19 %. Therefore, the element properties were found to be suitable for using as an electrode in EDM work when compared to that of the electrode prototype (EDM C3).
Synthesis and Characterization of Active Biocarbon Material for Use in Cosmetics and Personal Care Products
Authors: Abdullah Palsan Sannasi , Lim Jia Yi , Abdullah Nor Asfaliza
Published: May 2020

Consumer’s preference towards organic material enriched nature based green products in the cosmetics and personal care industry have intensified over the years. This paper shares the synthesis and characterization of an active organic biocarbon material derived from carbonized powdered coconut shell by bicarbonate cured activation for use in charcoal-based cosmetic and personal care products. The optimum conditions for activation was observed at 800 °C, run for 180 min, with a bicarbonate impregnation ratio of 1:3. Experimental design followed Box-Behnken approach. The increase in iodine (757.30 mg/g) and methylene blue number (111.00 mg/g) are indicative of a highly porous biocarbon material that reflects its excellent adsorption capability. Suitability of the biocarbon material for application in charcoal-based cosmetic formulation mixture was supported through proximate, texture, and color analysis. Overall material characteristics are beneficial for effective adsorbent and exfoliant functions in cleansing, detoxifying, and scrubbing.
Microstructure and Mechanical Properties of Laser Welded 316L SLM Parts
Authors: Rautio Timo , Mäkikangas Jarmo , Jaskari Matias , Keskitalo Markku , Järvenpää Antti
Published: May 2020

This paper focuses on a study conducted on laser welding of printed 316L parts that were produced with a selective laser melting process. Commercial sheet material was used as a reference for the printed 316L parts. The effect of heat treatment on joint properties, and on what stage of the process it should be applied, was studied with metallography and mechanical testing. Optical microscopy was applied to analyze the microstructure of the base material and the weld seam. Tensile testing was applied for determining monotonic strength of different structures. The printed base material showed higher strength, but lower ductility in comparison to the commercial sheet material. In the welded condition, tensile properties were impaired by the welding, but for the commercial sheet material, no clear effects were seen. The difference was hypothesized to be caused by the higher strength mismatch in the printed joints. For the welded structures, the best strength-ductility combination was achieved by heat treating the parts both before and after the laser welding.
Flavor Quality Changes of Turbot (Psetta maxima) Stored at -2 and 0°C
Authors: Zhao Hong Lei , Yin Yi Ming , Liu Ying , Xu Yong Xia , Li Xue Peng , Li Jian Rong
Published: May 2020

The effect of super-chilling at -2°C compared with ice storage at 0°C on flavor quality changes of turbot (Psetta maxima) was investigated. Changes in total volatile basic nitrogen (TVB-N), sensory attributes and volatile compounds were periodically examined for 20 days. Results demonstrated that super-chilling retarded the increases of TVB-N values and maintained better sensory quality compared to the ice storage. Additionally, GC-MS analysis showed super-chilling could more effectively maintain the characteristic volatiles responsible for fresh fish flavor and reduce the contents of putrid compounds such as TMA and acetic acid.
Analogy of Non-Destructive Tests for the Detection of Defectologies in Aluminium Cylinder Heads
Authors: Valencia Stephen S. , Galárraga Lily C. , Terán Héctor C. , Arteaga Oscar
Published: May 2020

The present experimental study proposes an alternative for diagnostic methods and quality control in cylinder head defectology. The composition of the material is characterized by spectrometry, obtaining an approximation of aluminum 2117. For the detection of defectologies, non-destructive tests (NDT) are carried out, applicable to cylinder heads such as: visual inspection (VT) under conditions of standard EN 13018, penetrating inks (PT) visible according to ASTM E 165-02 and others not yet included in the vehicle fleet.; infrared thermography (IRT) with equipment specifications under ISO 18434 - 1, ultrasound (UT) based on standard EN 583 for the use of the equipment and Eddy currents (ECT) conforming standard ISO 15548, the analysis is carried out on the flat surface of the cylinder head, combustion chamber, valve seats and intake - exhaust ports, the different defects found are: cracks, fissures, discontinuities and pitting, showing longitudinal dimensions from 0,8 [mm]. To determine the reliability of results, an analogy is made of the tests mentioned in the same defect, the method with the greatest scope is Eddy currents as it has more inspection coverage with respect to the remaining tests; the simulation of computer-aided engineering CAE of the defect is performed, applying an AC magnetic analysis to identify the flux density, current density and visualize how the Eddy currents act in the cylinder head. After this research, artificial intelligence will be used as a complementary diagnosis, to predict defectologies not perceived by the human eye and to obtain a better analysis of defectologies in cylinder heads.