bluuebunny/crossref_metadata_2025_split huggingface dataset:
Solar Kinetic Energy and Cross Helicity Spectra
Authors: Zhang Hongqi , Brandenburg Axel 
Published: July 2018

Abstract
We develop a formalism that treats the calculation of solar kinetic energy and cross helicity spectra in an equal manner to that of magnetic energy and helicity spectra. The magnetic helicity spectrum is shown to be equal to the vertical part of the current helicity spectrum divided by the square of the wavenumber. For the cross helicity, we apply the recently developed two-scale approach globally over an entire active region to account for the sign change between the two polarities. Using vector magnetograms and Dopplergrams of NOAA 11158 and 12266, we show that kinetic and magnetic energy spectra have similar slopes at intermediate wavenumbers, where the contribution from the granulation velocity has been removed. At wavenumbers around

, the magnetic helicity is found to be close to its maximal value. The cross helicity spectra are found to be within about 10% of the maximum possible value. Using the two-scale method for NOAA 12266, the global cross helicity spectrum is found to be particularly steep, similarly to what has previously been found in theoretical models of spot generation. In the quiet Sun, by comparison, the cross helicity spectrum is found to be small.
Icy Grains from the Nucleus of Comet C/2013 US10 (Catalina)
Authors: Protopapa Silvia , Kelley Michael S. P. , Yang Bin , Bauer James M. , Kolokolova Ludmilla , Woodward Charles E. , Keane Jacqueline V. , Sunshine Jessica M. 
Published: July 2018

Abstract
We present Infrared Telescope Facility/SpeX and NEOWISE observations of the dynamically new comet C/2013 US10 (Catalina), hereafter US10, from 5.8 au inbound, to near perihelion at 1.3 au, and back to 5.0 au outbound. We detect water ice in the coma of US10, assess and monitor the physical properties of the ice as insolation varies with heliocentric distance, and investigate the relationship between water ice and CO2. This set of measurements is unique in orbital coverage and can be used to infer both the physical evolution of the ice, and, potentially, the nucleus composition. We report (1) nearly identical near-infrared spectroscopic measurements of the coma at −5.8 au, −5.0 au, +3.9 au (where <0 au indicates pre-perihelion epochs), all presenting evidence of water-ice grains, (2) a dust-dominated coma at 1.3 and 2.3 au and, (3) an increasing CO2/Afρ ratio from −4.9 to 1.8 au. We propose that sublimation of the hyper-volatile CO2 is responsible for dragging water-ice grains into the coma throughout the orbit. Once in the coma, the observability of the water-ice grains is controlled by the ice grain sublimation lifetime, which seems to require some small dust contaminant (i.e., non-pure ice grains). At

, the ice grains are long-lived and may be unchanged since leaving the comet nucleus. We find that the nucleus of comet US10 is made of, among other components, ∼1 μm water-ice grains containing up to 1% refractory materials.
Reverse Current Model for Coronal Mass Ejection Cavity Formation
Authors: Haw Magnus A. , Wongwaitayakornkul Pakorn , Li Hui , Bellan Paul M. 
Published: July 2018

Abstract
We report here a new model for explaining the three-part structure of coronal mass ejections (CMEs). The model proposes that the cavity in a CME forms because a rising electric current in the core prominence induces an oppositely directed electric current in the background plasma; this eddy current is required to satisfy the frozen-in magnetic flux condition in the background plasma. The magnetic force between the inner-core electric current and the oppositely directed induced eddy current propels the background plasma away from the core, creating a cavity and a density pileup at the cavity edge. The cavity radius saturates when an inward restoring force from magnetic and hydrodynamic pressure in the region outside the cavity edge balances the outward magnetic force. The model is supported by (i) laboratory experiments showing the development of a cavity as a result of the repulsion of an induced reverse current by a rising inner-core flux-rope current, (ii) 3D numerical magnetohydrodynamic (MHD) simulations that reproduce the laboratory experiments in quantitative detail, and (iii) an analytic model that describes cavity formation as a result of the plasma containing the induced reverse current being repelled from the inner core. This analytic model has broad applicability because the predicted cavity widths are relatively independent of both the current injection mechanism and the injection timescale.
La prise de conscience de la nécessité d’une gouvernance plus responsable progresse
Authors: Notat Nicole , Crifo Patricia , Mahieux Xavier 
Published: July 2018

En matière de gouvernance, la situation française se caractérise par la coexistence de plusieurs modèles en raison de la multiplicité des formes juridiques (sociétés anonymes, mutualistes, etc.) et de la composition des conseils d’administration, parfois encore teintés de consanguinité, avec une dissociation ou non des pouvoirs qui fait encore débat et une très faible représentativité des salariés en leurs seins. Sur ce point, la France est réellement à la traîne et les réticences sont encore importantes, même si la loi Rebsamen impose cette représentation depuis 2015. Plus généralement, les freins à l’évolution vers une gouvernance socialement responsable sont liés à la représentation que les chefs d’entreprises se font de leur rôle et à la recherche de rentabilité, souvent à court terme, des investisseurs. Mais les choses évoluent, notamment du côté des investisseurs qui comprennent que leur intérêt d’actionnaires bien compris est de prendre en compte les intérêts des parties prenantes, en particulier sur les enjeux sociaux et environnementaux, et d’agir en ce sens auprès des entreprises. L’évolution de l’activité des agences de notation extra-financières telles que Vigeo confirme cette tendance. Classification JEL : G32, G34, K22, M12, M14.
L’évolution de l’actionnariat en France : 1977-2017
Authors: Auvray Tristan 
Published: July 2018

Cet article retrace les grandes tendances de l’actionnariat français des sociétés cotées et non cotées à partir de la fin des années 1970, et plus spécialement en ce début de xxi e siècle, vingt ans après l’éclatement du cœur financier français. Nous proposons une méthode originale, combinant les comptes de patrimoines et les statistiques sur les IDE de la Banque de France, ainsi que l’enquête CPIS du FMI, pour donner des ordres de grandeurs sur la localisation de cet actionnariat et le type de ses prises de participations. Pour caractériser de manière plus détaillée l’évolution de l’actionnariat des sociétés cotées françaises sur la période récente, nous nous focalisons ensuite sur les grandes sociétés de la place de Paris. Malgré la grande rupture qu’a été la montée des investisseurs institutionnels états-uniens à la fin des années 1990, l’actionnariat des grandes sociétés cotées a connu une forte stabilité dans ses niveaux de concentration depuis 2002, ce qui ne doit pas dissimuler la montée, aux côtés des actionnaires de contrôle traditionnels, de nouveaux actionnaires de contrôle (fonds souverains, hedge funds et groupes étrangers). De même, si la concentration des cinq premiers actionnaires est stable, les participations du premier actionnaire tendent à diminuer, conférant plus de poids relatif aux autres détenteurs de blocs d’actions. Classification JEL : G32, G34.
Familles actionnaires
Authors: Ginglinger Edith 
Published: July 2018

Les firmes familiales représentent une large part des entreprises cotées dans le monde. Les mécanismes de gouvernance des firmes familiales tiennent compte des spécificités de leurs conflits d’agence. Par exemple, les conflits d’agence entre actionnaires et dirigeants peuvent être atténués lorsque les dirigeants sont eux-mêmes membres de la famille. Les coûts des conflits d’agence entre le bloc familial majoritaire et les actionnaires minoritaires, liés aux prélèvements potentiels de bénéfices privés, peuvent être compensés par un contrôle plus efficace des dirigeants, tandis qu’un conflit d’agence spécifique lié aux relations entre la famille dans son ensemble et ceux qui la représentent dans l’organisation du bloc actionnarial peut émerger. Les mécanismes de gouvernance mis en place semblent efficaces, puisque les firmes familiales apparaissent plus performantes que les firmes non familiales. Mais elles sont également moins diversifiées, moins innovantes et plus sensibles au climat social dans l’entreprise. Leurs décisions financières reflètent le souci de leurs actionnaires familiaux de préserver leur contrôle qui passe en particulier par l’établissement de relations de long terme avec les autres parties prenantes de l’entreprise. Cet article propose une synthèse des résultats de recherches sur ces sujets. Classification JEL : G30, G32, L21, L25, P12.
Conflits d’intérêts et gouvernance des banques systémiques : éléments d’analyse critique
Authors: Scialom Laurence 
Published: July 2018

Nous définissons dans cet article deux grandes catégories de conflits d’intérêts concernant les banques systémiques : des conflits d’intérêts d’ordre microéconomique qui portent atteinte à la responsabilité fiduciaire des banques vis-à-vis de leurs clients et les conflits d’intérêts d’ordre macroéconomique qui nuisent à l’intérêt de la société dans son ensemble et alimentent la défiance sociale vis-à-vis des banques. L’hypothèse de cet article est que les scandales financiers à répétition qui éclaboussent les grandes banques systémiques internationales ne sont pas un épiphénomène, mais au contraire le symptôme des failles de leur gouvernance et des conflits d’intérêts non traités qui les minent. Le décryptage des conditions permissives au relâchement des normes éthiques dans la banque est important pour la stabilité financière, pour la confiance dans le système financier et devrait avoir des implications majeures en termes d’action publique. Nous plaidons donc pour que les économistes investissent ce terrain de recherche. Classification JEL : G21, G28, G34, G38.
Les défis socio-économiques liés à la chirurgie robot-assistée dans les blocs opératoires : espaces d’échanges et artefacts médiateurs
Authors: Wannenmacher Delphine 
Published: July 2018

L’arrivée de la robotique en chirurgie modifie l’activité des équipes de bloc opératoire. Elle engendre une reconfiguration spatiale du bloc et a un impact sur le fonctionnement de l’équipe de travail notamment au niveau de la communication et de l’organisation du travail. Les recherches dans le domaine mettent en avant l’intérêt de la check-list et le développement de compétences non techniques en insistant sur la formation et l’évaluation de ces dernières notamment dans un objectif de performance. Dans un cadre plus global d’apprentissage expansif et par le biais d’une démarche pragmatiste, nous proposons une autre piste : la création d’espaces d’échanges médiés par des artefacts pour transformer les pratiques au sein du bloc opératoire.
Internal barriers to supply chain management implementation in a South African traditional university
Authors: Masete Mamokgadi Z. , Mafini Chengedzai 
Published: July 2018

Background: The demand for higher education in South Africa continues to increase, placing pressure on public higher education institutions to satisfy this demand. Supply chain management is one of the practices that may be implemented to ensure that public universities improve their operations and can, therefore, meet the increased demand for higher education in the country.Objectives: This study aimed to explore the barriers to the implementation of supply chain management practices at a South African public university.Method: The study used a qualitative case study approach using a sample of 17 members of management and staff at a South African traditional university in the Limpopo Province. Data were collected using a combination of a focus group discussion and semi-structured in-depth interviews.Results: The study generated eight themes that embody the barriers to the implementation of supply chain management at the institution. These themes were labelled as stakeholder buy-in, knowledge of supply chain management, supply chain systems and processes, procurement policy and practices, implementation of supply chain management, stakeholder change management, human resource management and organisational culture.Conclusion: Various internal barriers impair the implementation of supply chain management practices at the institution. Administration at the institution has invested limited resources, time and initiatives to ensure the successful implementation of supply chain management. The focus should be directed to finding lasting solutions to each of the barriers identified in this study. Further studies should address the issue of external barriers to supply chain management in public higher education institutions.
Evaluating South Africa’s utilisation of sustained export potential in sub-Saharan Africa
Authors: Mhonyera Gabriel , Steenkamp Ermie , Matthee Marianne 
Published: July 2018

Background: Regional trade could be a powerful engine of economic growth and sustainable job creation. However, South Africa’s exports to sub-Saharan Africa (SSA) are typically smaller and more short-lived than its exports to its traditional markets. This is despite South African policymakers considering trade with SSA to be a priority. Aim: The aim of the article is to evaluate South Africa’s utilisation of sustained export potential in SSA with a view to providing practical insights that will inform future policymaking and planning. Setting: Despite the priority attention given to SSA in the country’s trade policy, South Africa is yet to make meaningful inroads into SSA’s largest and fastest-growing economies. Method: The research method applied comprised three steps. The first step involved the identification, over a five-year period from 2010 to 2014, of consistently large and/or growing import demand in SSA for all products at the Harmonised System (HS) six-digit level, as well as the identification of products South Africa consistently exported competitively (sustainable exports). The second step entailed matching SSA markets with consistently large and/or growing import demand to South Africa’s sustainable exports. The third step involved evaluating South Africa’s utilisation of sustained export potential in SSA. Results: The results reveal that South Africa is utilising just over half (54%) of its sustained export potential in SSA. Conclusion: South Africa is, therefore, underutilising or not utilising close to 50% of its sustained export potential in SSA. Most of the export potential that South Africa is utilising is in Eastern Africa while most of the export potential that the country is underutilising and not utilising at all is in Central and Western Africa.
A comparison of retirement saving using discretionary investment and Regulation 28
Authors: Willows Gizelle D. , Burgers Thomas , West Darron 
Published: July 2018

Background: There is growing uncertainty in global society with regard to how retirement savings should be approached. The primary reason for this is that most societies do not save enough and their citizens run out of money during retirement. Aim: This study investigates whether the limitations imposed by Regulation 28 of the Pension Funds Act of South Africa encourage optimal asset allocation and reduce investment risk for retirement savings when contrasted with discretionary investment. Setting: The study looks at hypothetical individuals who are subject to tax and retirement consequences as administered by South African legislation. Methods: A quantitative risk and return analysis was performed while considering two hypothetical investors who are identical in all aspects other than their choice of investments. Results: The findings indicate that Regulation 28 is effective in reducing the investment risk of retirement savings; however, it may also force the investor to sacrifice wealth. Conclusion: Depending on the tax bracket in which the investor sits, discretionary investment may be preferential to investing in a retirement fund under the mandate of Regulation 28.
Some password users are more equal than others: Towards customisation of online security initiatives
Authors: Butler Rika , Butler Martin 
Published: July 2018

Background: Online security is a growing concern and user authentication through passwords remains an important mechanism to protect online assets. Research to date has highlighted the need to address human behaviour but without an indication of where the emphasis of security education, training and awareness (SETA) initiatives should be, beyond improved password practices. Objectives: The aim of this study was to, through analysis of the password behaviour of South African online consumers: (1) understand the prevalence of poor password practices among consumers overall and (2) identify specific password deficiencies prevalent among different demographic groups to be focus areas for tailored intervention programmes. Method: The study uses a quantitative research approach. An online survey was used to gather demographic data, perceptions about online security and applied password practices. A sample of 737 valid responses was analysed for this research. Results: Based on the descriptive analysis of the responses three key observations were made. Firstly, there is a distinct difference in the incidence of poor password practices for all respondents and thus support for tailored interventions. Secondly, there are variances between the practices within different demographic groups that could be used for customisation of interventions. Finally, the different poor practices cannot be uniquely attributed to one particular set of demographics. Conclusion: The study concluded that to improve computer password security in South Africa, password SETA programmes should be customised for areas where individual needs exist and not merely per password practice or demographic group.
Cone-beam computed tomographic analysis on root and canal morphology of mandibular first permanent molar among multiracial population in Western European population
Authors: Gambarini Gianluca , Piasecki Lucila , Ropini Priscilla , Miccoli Gabriele , Nardo Dario Di , Testarelli Luca 
Published: July 2018

ABSTRACT
Objective: In the present study, confluent canals in the mandibular first molar's mesial root were investigated in an Italian population by means of cone-beam computed tomography (CBCT). Materials and Methods: A total of 200 molars, selected from the CBCT examinations of 130 patients who required this type of X-ray study as part of their dental treatment, were examined. The evaluated parameters were number of canals, root canal system configuration, presence of apical confluences, distance between confluences and apical foramina, which canal had a higher degree of curvature, and symmetry between left and right elements in the same individual. Statistical Analysis Used: Percentages of the cases were reported. Results: All the examined roots presented two canals. In 59% of cases, a Vertucci Type IV canal configuration was observed, while in 41% of cases, a Type II configuration was observed. Apical confluences were present in 41% of cases. The average distance between confluences and apical foramina was 2.85 mm. When confluences were present, the mesiobuccal canal showed a higher degree of curvature in 78% of cases. Symmetry in Vertucci configuration was seen in 88% of cases. Conclusions: Apical confluences in the mesial roots of mandibular molar can be present in a significantly high number of cases, and their recognition is essential to prevent the iatrogenic errors during canal instrumentation.
Cytotoxicity of chlorhexidine and neem extract on cultured human gingival fibroblasts through
fluorescence-activated cell sorting analysis : An in-vitro study
Authors: Verma Umesh Pratap , Gupta Abhaya , Yadav Rakesh Kumar , Tiwari Rini , Sharma Ramesh , Balapure Anil Kumar 
Published: July 2018

ABSTRACT
Objective: To assess the influence of chlorhexidine (CHX), neem vehicle control (NVC), and neem extract (NE) on cultured human gingival fibroblasts (hGFs) using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and fluorescence-activated cell sorting (FACS) analysis. Materials and Methods: Fibroblasts were derived from healthy gingival biopsy specimens harvested aseptically. The effects of CHX, NVC, and NE were evaluated on cultured hGFs through FACS and MTT assay. Results: MTT assay with hGFs indicated altered morphology with maximum cell death at 10% CHX, while NVC and NE showed similar results at a concentration of 75% and above. On FACS analysis, beyond 1%, CHX adversely affected the cell cycle phase distribution whereas NE exerted a detrimental effect only at 100%. Moreover, both with NVC and NE cells were well differentiated in all the three phases of the cell cycle, with distinction getting lost at 50% to finally causing cell death at 100%. Conclusions: CHX beyond 1% concentration exhibited a toxic effect on hGFs at 1, 5, and 15 min time exposure. However, NE did not adversely affect the fibroblasts even up to 50% concentration showing a less toxic effect in comparison with CHX on these cells. The cytoprotective and oral friendly quality of NE emphaisze the superiority of NE over CHX.
Incidence of periodontal compromise in teeth indicated for undergoing endodontic treatment: A clinical study
Authors: Machado Ricardo , Cunha Monique Muniz da , Comparin Daniel , Cosme-Silva Leopoldo , Back Eduardo Donato Eing Engelke , Garcia Lucas da Fonseca Roberti 
Published: July 2018

ABSTRACT
Objective: The aim of this study was to evaluate the periodontal status of teeth indicated for undergoing endodontic treatment. Materials and Methods: Two hundred and nine teeth were evaluated using probing depth tests at three vestibular and three palatine/lingual sites before the patients underwent treatment. Teeth that presented up to 3-mm probing depth were considered as healthy. Those that presented at least one site with probing depth >3 mm were considered periodontally compromised. The data were statistically analyzed by means of applying the Chi-square test, with a level of significance of 5%. Results: Of the total of 209 teeth evaluated, 40 (19.10%) presented periodontal compromise. There was statistically significant difference related to the compromised teeth of patients of the female gender (22.80%) compared with teeth of patients of the male gender (12.30%) (P < 0.05). Conclusions: Fewer than 20% of the teeth evaluated presented a periodontal compromise. Patients of the female gender presented a higher number of periodontally compromised teeth than patients of the male gender.