bluuebunny/crossref_metadata_2025 huggingface dataset:
Testing Systematics of Gaia DR2 Parallaxes with Empirical Surface Brightness: Color Relations Applied to Eclipsing Binaries
Authors: Graczyk Dariusz , Pietrzyński Grzegorz , Gieren Wolfgang , Storm Jesper , Nardetto Nicolas , Gallenne Alexandre , Maxted Pierre F. L. , Kervella Pierre , Kołaczkowski Zbigniew , Konorski Piotr , Pilecki Bogumił , Zgirski Bartłomiej , Górski Marek , Suchomska Ksenia , Karczmarek Paulina , Taormina Mónica , Wielgórski Piotr , Narloch Weronika , Smolec Radosław , Chini Rolf , Breuval Louise
Published: February 2019

Using a sample of 81 galactic, detached eclipsing binary stars we investigated the global zero-point shift of their parallaxes with the Gaia Data Release 2 (DR2) parallaxes. The stars in the sample lay in a distance range of 0.04–2 kpc from the Sun. The photometric parallaxes ϖ
Phot of the eclipsing binaries were determined by applying a number of empirical surface brightness–color (SBC) relations calibrated on optical-infrared colors. For each SBC relation we calculated the individual differences

and then we calculated unweighted and weighted means. As the sample covers the whole sky we interpret the weighted means as the global shifts of the Gaia DR2 parallaxes with respect to our eclipsing binary sample. Depending on the choice of the SBC relation the shifts vary from −0.094 to −0.025 mas. The weighted mean of the zero-point shift from all colors and calibrations used is dϖ = −0.054 ± 0.024 mas. However, the SBC relations based on (B − K) and (V − K) colors, which are the least reddening dependent and have the lowest intrinsic dispersions, give a zero-point shift of dϖ = −0.031 ± 0.011 mas in full agreement with results obtained by Lindegren et al. and Arenou et al. Our result confirms the global shift of Gaia DR2 parallaxes of dϖ = −0.029 mas reported by the Gaia team, but we do not confirm the larger zero-point shift reported by a number of follow-up papers.
Protoplanetary Disk Rings and Gaps across Ages and Luminosities
Authors: van der Marel Nienke , Dong Ruobing , di Francesco James , Williams Jonathan P. , Tobin John
Published: February 2019

Since the discovery of the multiring structure of the HL Tau disk, ALMA data suggest that the dust continuum emission of many, if not all, protoplanetary disks consists of rings and gaps, no matter their spectral type or age. The origin of these gaps so far remains unclear. We present a sample study of 16 disks with multiple ring-like structures in the continuum, using published ALMA archival data, to compare their morphologies and gap locations in a systematic way. The 16 targets range from early- to late-type stars, from <0.5 Myr to >10 Myr and from ∼0.2 to 40 L
⊙, and include both full and transitional disks with cleared inner dust cavities. Stellar ages are revised using new Gaia distances. Gap locations are derived using a simple radial fit to the intensity profiles. Using a radiative transfer model, the temperature profiles are computed. The gap radii generally do not correspond to the orbital radii of snow lines of the most common molecules. A snow line model can likely be discarded as a common origin of multiring systems. In addition, there are no systematic trends in the gap locations that could be related to resonances of planets. Finally, the outer radius of the disks decreases for the oldest disks in the sample, indicating that if multiring disks evolve in a similar way, outer dust rings either dissipate with the gas or grow into planetesimal belts.
Toward More Reliable Analytic Thermochemical-equilibrium Abundances
Authors: Cubillos Patricio E. , Blecic Jasmina , Dobbs-Dixon Ian
Published: February 2019

Heng & Tsai developed an analytic framework to obtain thermochemical-equilibrium abundances for

, CO,

,

,

,

,

,

, and

for a system with known temperature, pressure, and elemental abundances (hydrogen, carbon, nitrogen, and oxygen). However, the implementation of their approach can become numerically unstable under certain circumstances, leading to inaccurate solutions (e.g., C/O ≥ 1 atmospheres at low pressures). Building on their approach, we identified the conditions that prompt inaccurate solutions, and developed a new framework to avoid them, providing a reliable implementation for arbitrary values of temperature (200 to ∼2000 K), pressure (

to

bar), and CNO abundances (

to ∼

×  solar elemental abundances), for hydrogen-dominated atmospheres. The accuracy of our analytic framework is better than 10% for the more abundant species that have mixing fractions larger than

, whereas the accuracy is better than 50% for the less abundant species. Additionally, we added the equilibrium-abundance calculation of atomic and molecular hydrogen into the system, and explored the physical limitations of this approach. Efficient and reliable tools, such as this one, are highly valuable for atmospheric Bayesian studies, which need to evaluate a large number of models. We implemented our analytic framework into the rate Python open-source package, available at https://github.com/pcubillos/rate.
r-process Enrichment of the Ultra-faint Dwarf Galaxies by Fast-merging Double-neutron Stars
Authors: Safarzadeh Mohammadtaher , Ramirez-Ruiz Enrico , Andrews Jeff. J. , Macias Phillip , Fragos Tassos , Scannapieco Evan
Published: February 2019

The recent aLIGO/aVirgo discovery of gravitational waves from the neutron star merger (NSM) GW170817 and the follow-up kilonova observations have shown that NSMs produce copious amounts of r-process material. However, it is difficult to reconcile the large natal kicks and long average merging times of double-neutron stars (DNSs) with the levels of r-process enrichment seen in ultra-faint dwarf (UFD) galaxies such as Reticulum II and Tucana III. Assuming that such dwarf systems have lost a significant fraction of their stellar mass through tidal stripping, we conclude that contrary to most current models, it is the DNSs with rather large natal kicks but very short merging timescales that can enrich UFD-type galaxies. These binaries are either on highly eccentric orbits or form with very short separations due to an additional mass transfer between the first-born neutron star and a naked helium star, the progenitor of the second neutron star. These DNSs are born with a frequency that agrees with the statistics of the r-process UFDs, and merge well within the virial radius of their host halos, therefore contributing significantly to their r-process enrichment.
Improved Dynamical Constraints on the Masses of the Central Black Holes in Nearby Low-mass Early-type Galactic Nuclei and the First Black Hole Determination for NGC 205
Authors: Nguyen Dieu D. , Seth Anil C. , Neumayer Nadine , Iguchi Satoru , Cappellari Michelle , Strader Jay , Chomiuk Laura , Tremou Evangelia , Pacucci Fabio , Nakanishi Kouichiro , Bahramian Arash , Nguyen Phuong M. , den Brok Mark , Ahn Christopher C. , Voggel Karina T. , Kacharov Nikolay , Tsukui Takafumi , Ly Cuc K. , Dumont Antoine , Pechetti Renuka
Published: February 2019

We improve the dynamical black hole (BH) mass estimates in three nearby low-mass early-type galaxies: NGC 205, NGC 5102, and NGC 5206. We use new Hubble Space Telescope (HST)/STIS spectroscopy to fit the star formation histories of the nuclei in these galaxies, and use these measurements to create local color–mass-to-light ratio (M/L) relations. We then create new mass models from HST imaging and combined with adaptive optics kinematics, we use Jeans dynamical models to constrain their BH masses. The masses of the central BHs in NGC 5102 and NGC 5206 are both below one million solar masses and are consistent with our previous estimates,

M
⊙ and

M
⊙ (3σ errors), respectively. However, for NGC 205, the improved models suggest the presence of a BH for the first time, with a best-fit mass of

M
⊙ (3σ errors). This is the least massive central BH mass in a galaxy detected using any method. We discuss the possible systematic errors of this measurement in detail. Using this BH mass, the existing upper limits of both X-ray, and radio emissions in the nucleus of NGC 205 suggest an accretion rate ≲10−5 of the Eddington rate. We also discuss the color–M/L
eff relations in our nuclei and find that the slopes of these vary significantly between nuclei. Nuclei with significant young stellar populations have steeper color–M/L
eff relations than some previously published galaxy color–M/L
eff relations.
Influence of Nuclear Reaction Rate Uncertainties on Neutron Star Properties Extracted from X-Ray Burst Model–Observation Comparisons
Authors: Meisel Zach , Merz Grant , Medvid Sophia
Published: February 2019

Type-I X-ray bursts can be used to determine properties of accreting neutron stars via comparisons between model calculations and astronomical observations, exploiting the sensitivity of models to astrophysical conditions. However, the sensitivity of models to nuclear physics uncertainties calls into question the fidelity of constraints derived in this way. Using X-ray burst model calculations performed with the code MESA, we investigate the impact of uncertainties for nuclear reaction rates previously identified as influential and compare them to the impact of changes in astrophysical conditions, using the conditions that are thought to best reproduce the source GS 1826-24 as a baseline. We find that reaction rate uncertainties are unlikely to significantly change conclusions about the properties of accretion onto the neutron star surface for this source. However, we find that reaction rate uncertainties significantly hinder the possibility of extracting the neutron star mass–radius ratio by matching the modeled and observed light curves, due to the influence of reaction rates on the modeled light curve shape. Particularly influential nuclear reaction rates are 15O(α, γ) and 23Al(p, γ), though other notable impacts arise from 14O(α, p), 18Ne(α, p),

, 24Mg(α, γ),

, and 61Ga(p, γ). Furthermore, we find that varying some nuclear reaction rates within their uncertainties has an impact on the neutron star crust composition and thermal structure that is comparable to relatively significant changes to the accretion conditions.
Revealing Reionization with the Thermal History of the Intergalactic Medium: New Constraints from the Lyα Flux Power Spectrum
Authors: Boera Elisa , Becker George D. , Bolton James S. , Nasir Fahad
Published: February 2019

We present a new investigation of the thermal history of the intergalactic medium (IGM) during and after reionization using the Lyα forest flux power spectrum at 4.0 ≲ z ≲ 5.2. Using a sample of 15 high-resolution spectra, we measure the flux power down to the smallest scales ever probed at these redshifts (−1 ≲ log(k/km−1 s) ≲ −0.7). These scales are highly sensitive to both the instantaneous temperature of the IGM and the total energy injected per unit mass during and after reionization. We measure temperatures at the mean density of T
0 ∼ 7000–8000 K, consistent with no significant temperature evolution for redshifts 4.2 ≲ z ≲ 5.0. We also present the first observational constraints on the integrated IGM thermal history, finding that the total energy input per unit mass increases from u
0 ∼ 4.6 to 7.3 eV

from z ∼ 6 to 4.2 assuming a ΛCDM cosmology. We show how these results can be used simultaneously to obtain information on the timing and the sources of the reionization process. Our first proof of concept using simplistic models of instantaneous reionization produces results comparable to and consistent with the recent Planck constraints, favoring models with

.
Temperature Structure in the Inner Regions of Protoplanetary Disks: Inefficient Accretion Heating Controlled by Nonideal Magnetohydrodynamics
Authors: Mori Shoji , Bai Xue-Ning , Okuzumi Satoshi
Published: February 2019

The gas temperature in protoplanetary disks (PPDs) is determined by a combination of irradiation heating and accretion heating, with the latter conventionally attributed to turbulent dissipation. However, recent studies have suggested that the inner disk (a few au) is largely laminar, with accretion primarily driven by magnetized disk winds, as a result of nonideal magnetohydrodynamic (MHD) effects from weakly ionized gas, suggesting an alternative heating mechanism by Joule dissipation. We perform local stratified MHD simulations including all three nonideal MHD effects (ohmic, Hall, and ambipolar diffusion) and investigate the role of Joule heating and the resulting disk vertical temperature profiles. We find that in the inner disk, as ohmic and ambipolar diffusion strongly suppress electrical current around the midplane, Joule heating primarily occurs at several scale heights above the midplane, making the midplane temperature much lower than that with the conventional viscous heating model. Including the Hall effect, Joule heating is enhanced/reduced when the magnetic fields threading the disks are aligned/anti-aligned with the disk rotation, but it is overall ineffective. Our results further suggest that the midplane temperature in the inner PPDs is almost entirely determined by irradiation heating, unless viscous heating can trigger thermal ionization in the disk innermost region to self-sustain magnetorotational instability turbulence.
Polluted White Dwarfs: Mixing Regions and Diffusion Timescales
Authors: Bauer Evan B. , Bildsten Lars
Published: February 2019

Many isolated white dwarfs (WDs) show spectral evidence of atmospheric metal pollution. Since heavy-element sedimentation timescales are short, this most likely indicates ongoing accretion. Accreted metals encounter a variety of mixing processes at the WD surface: convection, gravitational sedimentation, overshoot, and thermohaline instability. We present MESA WD models that explore each of these processes and their implications for inferred accretion rates. We provide diffusion timescales for many individual metals, and we quantify the regimes in which thermohaline mixing dominates over gravitational sedimentation in setting the effective settling rate of the heavy elements. We build upon and confirm earlier work finding that accretion rates as high as

are needed to explain the observed pollution in DA WDs for T
eff > 15,000 K, and we provide tabulated results from our models that enable accretion rate inferences from observations of polluted DA WDs. If these rates are representative of young WDs, we estimate that the total mass of planetesimal material accreted over a WD lifetime may be as high as

, though this estimate is susceptible to potential selection biases and uncertainties about the nature of disk processes that supply accretion to the WD surface. We also find that polluted DB WDs experience much less thermohaline mixing than DA WDs, and we do not expect thermohaline instability to be active for polluted DB WDs with

.
Merging Cluster Collaboration: Optical and Spectroscopic Survey of a Radio-selected Sample of 29 Merging Galaxy Clusters
Authors: Golovich N. , Dawson W. A. , Wittman D. M. , Jee M. J. , Benson B. , Lemaux B. C. , van Weeren R. J. , Andrade-Santos F. , Sobral D. , de Gasperin F. , Brüggen M. , Bradač M. , Finner K. , Peter A.
Published: February 2019

Multi-band photometric and multi-object spectroscopic surveys of merging galaxy clusters allow for the characterization of the distributions of constituent DM and galaxy populations, constraints on the dynamics of the merging subclusters, and an understanding of galaxy evolution of member galaxies. We present deep photometric observations from Subaru/SuprimeCam and a catalog of 4431 spectroscopic galaxies from Keck/DEIMOS observations of 29 merging galaxy clusters ranging in redshift from z = 0.07 to 0.55. The ensemble is compiled based on the presence of radio relics, which highlight cluster-scale collisionless shocks in the intracluster medium. Together with the spectroscopic and photometric information, the velocities, timescales, and geometries of the respective merging events may be tightly constrained. In this preliminary analysis, the velocity distributions of 28 of the 29 clusters are shown to be well fit by single Gaussians. This indicates that radio-relic mergers largely occur transverse to the line of sight and/or near-apocenter. In this paper, we present our optical and spectroscopic surveys, preliminary results, and a discussion of the value of radio-relic mergers for developing accurate dynamical models of each system.
Comparing Treatments of Weak Reactions with Nuclei in Simulations of Core-collapse Supernovae
Authors: Nagakura Hiroki , Furusawa Shun , Togashi Hajime , Richers Sherwood , Sumiyoshi Kohsuke , Yamada Shoichi
Published: February 2019

We perform an extensive study of the influence of nuclear weak interactions on core-collapse supernovae, paying particular attention to consistency between nuclear abundances in the equation of state (EOS) and nuclear weak interactions. We compute properties of uniform matter based on the variational method. For inhomogeneous nuclear matter, we take a full ensemble of nuclei into account with various finite-density and thermal effects and directly use the nuclear abundances to compute nuclear weak interaction rates. To quantify the impact of a consistent treatment of nuclear abundances on CCSN dynamics, we carry out spherically symmetric CCSN simulations with full Boltzmann neutrino transport, systematically changing the treatment of weak interactions, EOSs, and progenitor models. We find that the inconsistent treatment of nuclear abundances between the EOS and weak interaction rates weakens the EOS dependence of both the dynamics and neutrino signals. We also test the validity of two artificial prescriptions for weak interactions of light nuclei and find that both prescriptions affect the dynamics. Furthermore, there are differences in neutrino luminosities by ∼10% and in average neutrino energies by 0.25–1 MeV from those of the fiducial model. We also find that the neutronization burst neutrino signal depends on the progenitor more strongly than on the EOS, preventing a detection of this signal from constraining the EOS.
The Spectral Properties of the Bright Fast Radio Burst Population
Authors: Macquart J.-P. , Shannon R. M. , Bannister K. W. , James C. W. , Ekers R. D. , Bunton J. D.
Published: February 2019

We examine the spectra of 23 fast radio bursts (FRBs) detected in a fly’s-eye survey with the Australian SKA Pathfinder, including those of three bursts not previously reported. The mean spectral index of

(F

ν
∝ ν

α
) is close to that of the Galactic pulsar population. The sample is dominated by bursts exhibiting a large degree of spectral modulation: 17 exhibit fine-scale spectral modulation with an rms exceeding 50% of the mean, with decorrelation bandwidths (half-maximum) ranging from ≈1 to 49 MHz. Most decorrelation bandwidths are an order of magnitude lower than the ≳30 MHz expected of Galactic interstellar scintillation at the Galactic latitude of the survey,

. However, these bandwidths are consistent with the ∼ν
4 scaling expected of diffractive scintillation when compared against the spectral structure observed in bright UTMOST FRBs detected at 843 MHz. A test of the amplitude distribution of the spectral fluctuations reveals only 12 bursts consistent at better than a 5% confidence level with the prediction of 100%-modulated diffractive scintillation. Five of six FRBs with a signal-to-noise ratio exceeding 20 are only consistent with this prediction at less than 1% confidence. Nonetheless, there is weak evidence (92%–94% confidence) of an anti-correlation between the amplitude of the spectral modulation and dispersion measure (DM), which suggests that it originates as a propagation effect. This effect is corroborated by the smoothness of the higher-DM Parkes FRBs, and could arise due to quenching of diffractive scintillation (e.g., in the interstellar medium of the host galaxy) by angular broadening in the intergalactic medium.
The Simultaneous Formation of Cored, Tangentially Biased, and Kinematically Decoupled Centers in Massive Early-type Galaxies
Authors: Rantala Antti , Johansson Peter H. , Naab Thorsten , Thomas Jens , Frigo Matteo
Published: February 2019

We study the impact of merging supermassive black holes (SMBHs) on the central regions of massive early-type galaxies (ETGs) using a series of merger simulations with varying mass ratios. The ETG models include realistic stellar and dark matter components and are evolved with the gadget-3 based regularized tree code ketju. We show that observed key properties of the nuclear stellar populations of massive ETGs, namely flat stellar density distributions (cores), tangentially biased velocity distributions, and kinematically decoupled (counter-)rotation, can naturally result from a single process—the scouring by SMBHs. Major mergers with mass ratios of q > 1/3 produce flat, tangentially biased cores with kinematically distinct components. These kinematic features originate from reversals of the SMBH orbits caused by gravitational torques after pericenter passages. Minor mergers (q ≲ 1/3), on the other hand, form non-rotating cores and the orbit reversal becomes less important. Low-density stellar cores scoured in (multiple) minor mergers are less tangentially biased. This implies that the nuclear stellar properties of massive ETGs can be solely explained by stellar dynamical processes during their final assembly without any need for “feedback” from accreting black holes. We predict a strong correlation between decoupled cores, central anisotropy, and merger history: decoupled cores form in binary mergers and we predict them to occur in elliptical galaxies with the strongest central anisotropy. Measurements of the central orbital structure are the key to understanding the number of mergers that a given galaxy has experienced.
Towards a general theory of social and economic development: Evolution of coordination mechanisms
Authors: Polterovich Victor
Published: February 2019

A new approach to understanding social and economic development is proposed, based on consideration of the evolution of coordination mechanisms. The work consists of two parts. In the first part, a critical analysis of four recently proposed theories of social development, focusing on geographical, institutional or cultural factors, is given. These theories have greatly enriched our understanding of the evolution of society, however, as analysis shows, none of them provides a satisfactory description of the driving forces and mechanisms of this evolution; the main reason is rooted in their common deficiency — monocausality. It is proposed to distinguish between two types of development, catching up and leading. The basic ideas of the theory of catching up development are presented. This approach makes it possible to explain the phenomenon of the “economic miracle” as a result of mutually conditioned changes in culture, institutions, technological progress and well-being in the context of interaction of competition, power and collaboration mechanisms.

The second part is devoted to the theory of leading socioeconomic development. It is shown how in Western Europe, as a result of the interaction of the above four factors, specific forms and combinations of the three main mechanisms of coordination — competition, power and collaboration — emerged at each stage of evolution. I emphasize the importance of ideology and the phenomenon of technical progress in the formation of institutions of economic and political competition that contributed to the creation of the welfare state. These changes and economic growth created the conditions for further transformation of civil culture: increasing levels of trust, tolerance, altruism and cosmopolitanism, expanding the planning horizon. The decrease in the level of coercion built into the mechanisms of power and competition are demonstrated as well as the expansion of the role of collaboration. A hypothesis is advanced that the speed of this process depends on geographical factors. The idea of the welfare world is discussed.
Les sanctions individuelles prises par le Conseil de sécurité et les exigences du droit à un procès équitable
Authors: Rota Marie
Published: February 2019

L’objet de cette contribution est de montrer que si les juridictions ou quasi-juridictions internationales qui sont chargées d’appliquer et de protéger les droits de l’homme (CJUE, Comité, Cour européenne et Cour interaméricaine des droits de l’homme) reconnaissent que l’application des sanctions individuelles adoptées par le Conseil de sécurité de l’ONU doit respecter les exigences d’un droit à un procès équitable, leurs motivations divergent. Ceci s’explique par la façon dont elles appréhendent les rapports entretenus entre le droit international général et le droit qu’elles sont spécifiquement chargées d’appliquer. Alors que la CJUE et le Comité des droits de l’homme adoptent une vision que l’on pourrait qualifier d’autonomiste, la Cour interaméricaine se livre clairement à une lecture universaliste du droit international au sein duquel elle s’intègre. La Cour européenne adopte quant à elle un positionnement bien plus ambigu qui s’explique par les divergences existantes entre les juges qui la composent. Cela aboutit à un raisonnement plus critiquable par son manque de clarté et qui s’explique, selon l’auteure, par une vision jusnaturaliste mal assumée.
Extending the Technology Acceptance Model to Understand Students’ Use of Learning Management Systems in Saudi Higher Education
Authors: Binyamin Sami Saeed , Rutter Malcolm , Smith Sally
Published: February 2019

Although learning management systems (LMS) have been widely adopted by higher educational institutions in many countries, they are considered an emerging technology in Saudi Arabia. Furthermore, research has demonstrated that the students’ use of them is not always satisfactory. This quantitative study investigated the factors that affect the students use of LMS in higher education by extending the technology acceptance model (TAM) and adapting eight external variables. Based on the probability multi-stage cluster sampling technique, online surveys were sent by email to 2000 students registered in three public universities in Saudi Arabia. 851 responses were submitted by participants, and 833 responses were used for data analysis. Using Partial Least Squares Structural Equations Modeling (PLS-SEM), the results revealed that perceived ease of use is affected by six factors (content quality, system navigation, ease of access, system interactivity, instructional assessment and system learnability). The findings confirmed that perceived usefulness has five determinants (content quality, learning support, system interactivity, instructional assessment and perceived ease of use). This research is relevant to researchers, decision makers and e-learning systems designers working to enhance students’ use of e-learning systems in higher education, in particular where there is not yet widespread adoption.
An Effective Approach for Clickbait Detection Based on Supervised Machine Learning Technique
Authors: Daoud Daoud M. , Abou El-Seoud Samir
Published: February 2019

Clickbait is a term used to describe a deceiving web content that uses ambiguity to prompt the user into clicking a link. It aims to increase the number of online readers in order to generate more advertising revenue. In other words, Clickbait is used to describe a type of hyperlink on a web page which seduces a user to click a link to continue reading a specific article.Typically such links will forward the visitor to a page that requires payment, registration, or lead a user to a site, which tries to sell user something or possibly extort user, by withholding the promised "bait".  We use supervised machine learning to create a model that is trained on 24 features. This method achieved an F1-score of 79% and an area under the ROC curve of 0.7.  Our methodology emphasises the importance of using features extracted from different elements of social media posts along with features that are extracted from the title and the article. In this research, we show that it is possible to identify Clickbaits using all parts of the post while keeping the number of features as minimum as possible.
¡Morir…, dormir! ¡dormir!... ¡tal vez soñar!
Authors: Sánchez Biosca Vicente
Published: February 2019

Los olvidados, el film que levantó ampollas en México por su realismo inmisericorde, está atravesado por un sueño, el de su protagonista Pedro. El presente artículo analiza los mecanismos formales de este sueño, apoyándose en el guión de Luis Alcoriza y Luis Buñuel y las anotaciones manuscritas hechas por este último. A continuación, reflexiona sobre la condición del sueño en la estética surrealista, es decir, su relación con la pesadilla y con el realismo, concluyendo sobre la manera específica en que el director aragonés entiende el concepto de surrealismo. Por último, el artículo aborda la representación de los mecanismos pulsionales que mueven a los personajes de Los olvidados, a saber, los procedimientos cinematográficos que expresan la ira, el frenesí y el desenfreno de las criaturas buñuelianas.
Los Cuatrocientos Golpes (Truffaut, 1959) des de Los olvidados (Buñuel, 1950)
Authors: Tuñón Julia
Published: February 2019

El presente trabajo atiende a la película de Francois Truffaut, Los cuatrocientos golpes, comparándola con Los olvidados, de Luis Buñuel, pues las similitudes entre ambas son notables. El tema común de la infancia y la delincuencia desborda en ambos casos la anécdota para manifestar algunos problemas de orden social, pero también emocional y psicológico que atañen a los niños en situaciones límite. Además de la historia narrada, las películas coinciden en múltiples aspectos formales, iconográficos, temáticos, y en algo mucho más fuerte y esencial: ciertos arquetipos de la condición humana que se expresan de manera superlativa en el paso a la vida adulta.
Reflections on the Effect of Organizational Restructuring
Authors: Oncioiu Ionica , Mândricel Diana Andreea
Published: February 2019

This chapter presents a new perspective on processes of change and adaptation to changes in Albanian telecommunications companies in order to maintain their position on the market. The objective of organizational changes, as a continuous process of experimentation and adaptation, is to correlate the capacities of an adaptation company to the business environment. The results of the study have shown that successful management of change is important for the survival and success of any company in the current environment in Albania. To take advantage of the benefits of organizational change stimulated mainly through innovation, companies need to think, act holistically, and make multi-level changes.
The Performance and Competitiveness of Romanian Enterprises in the European Economic Area
Authors: Gherghina Rodica , Duca Ioana , Caragea Nicoleta
Published: February 2019

The scientific approach of the authors' aims at highlighting the performance of the Romanian enterprises, based on the statistical indicators, and their competitiveness in the national and European economic space. Romanian companies are facing a decline in productivity lately, mainly due to a shortage of qualified workforce. Exodus of the skilled labor force towards the European market has led, most of the time, especially among small and medium enterprises, to reducing their activity, decreasing their productivity, and implicitly, to decreasing the profit rate. In this context, the competitiveness of Romanian companies in the European economic space has dropped considerably. Throughout the research, the authors highlight the economic impact due to the use of an unskilled workforce, which led to a low productivity and a decrease in the performance of the enterprises. The research is the results of the analysis of the statistical data, mainly provided by National Institute of Statistics surveys.
Drawing the Technologies of Improving the Methods of Crisis Management Based on a Complex Approach
Authors: Mocanu Nelu
Published: February 2019

The purpose of any modern economic politics is to ensure the stability and economic growth. In order to achieve this goal, each economic agent models (builds) an individual economic strategy. The building of the actual economic model is influenced by many factors – political, geographical, national, and cultural. Today, by the notion of crisis, we understand an aggravation of the discrepancies of the social-economic system that threaten its stability. Specialist that deal with problems of crisis management claim that measures must be taken when the financial results of the enterprise become unsatisfactory, when symptoms of an unfavorable situation of the activity of enterprise appear. This chapter presents the economic-organizational analysis of the strategies applied in the anti-crisis management.
The Role of Internal Controls in Corporate Governance Systems
Authors: Oba Ibrahim
Published: February 2019

The recent scandals and corporate failures in the United States and in Europe have led to a renewed interest in research of corporate governance. The objective of this chapter was to explore the role of internal control in enhancing the corporate governance and supervise the functionality of the implementation of the corporate government principles. The results show that the internal control has a significant role in enhancing the corporate governance pillars in companies, and the successes of corporate governance requires compliance with all elements of internal control.
Performance as a Result of Managerial Accounting and Leadership Vision
Authors: Stanciu Alina
Published: February 2019

Achieving performance remains the desire of entities, both those present in the competitive market, and new start-ups that break the existing markets, capitalizing on the opportunities offered by an external environment characterized by volatility, uncertainty, complexity, and ambiguity, but also the present digitalization, internet of things (IoT), 5G internet, and e-platforms. Seen as a reflection of the clear vision of extremely powerful leaders, the overall performance of the entity is attained today against the background of the innovation process. This chapter presents radiography of the new research and deepening directions at the intersection of accounting and management, between science and practice, with the role of potentiating performance as a result of managerial accounting and leadership vision.
Managing Customer Journeys in a Nimble Way for Industry 4.0
Authors: Janssens Jurgen
Published: February 2019

In the Fourth Industrial Revolution, customers expect companies to provide journeys in line with rapidly changing expectations. This allows for great potential for project portfolios that can enable tailored experiences, powered by technology and insights coming from the 360° view of the customer, to improve the experience and touchpoints before, during or after the main interaction of customers with a company. This chapter will illustrate that project managers need to master a dual dynamic to do so. On the one hand, new types of projects, changing expectations and shifting habits offer humbling challenges. On the other hand, governance, change and delivery continue to be the foundational baseline. By integrating theoretical insights and real-life cases from conservative and progressive industries, the author wants to stimulate project managers. Rather than seeing Industry 4.0 as a transformational tsunami, they should see it as an opportunity to remain curious, nimble and committed, while working in a reality where rapidly changing demand entails growth, learning and great value.
Issues Associated With Microgrid Integration
Authors: Khan Baseem , Tanwar Sudeep
Published: February 2019

Microgrid (MG) is the vital technology that can be utilized to supply electricity to rural areas by fulfilling various aspects of electricity such as sustainability and reliability. Further, MG technology can also be used as localized generation sources and back up supply source. As MG can be worked in interconnected mode, various issues related to interconnection with utility grid are raised. Several issues such as technical, regulatory, and operational are associated with grid integration. Therefore, this chapter deals with the issues that are associated with the grid integration of microgrid.
Economic Operation of Smart Micro-Grid
Authors: Khan Baseem , Singh Pawan
Published: February 2019

Presently, economic operation of micro-grid is a major concern in smart grid environment. This is a very complex problem, which can be solved with the help of various meta-heuristic techniques. Therefore, this chapter provides a comparative analysis of four different renowned meta-heuristic techniques with reference to the problem of optimal operation of micro-grid (MG). Genetic algorithm (GA), particle swarm optimization (PSO), differential evaluation (DE), and firefly (FF) algorithm are utilized for this purpose.
A Novel Approach to Fuzzy Model Identification Based on Bat Algorithm
Authors: Bansal Neety , Kaur Parvinder
Published: February 2019

The identification of a fuzzy model is a complex and nonlinear problem. This can be formulated as a search and optimisation problem and many computing approaches are available in the literature to solve this problem. This research paper is focused on using a new nature inspired approach for fuzzy modeling based on Bat Algorithm which is derived from the behaviour of micro-bats to search for their prey. The bat algorithm approach has been implemented and validated successfully on a rapid battery charger fuzzy controller problem. Currently, the key requirement is real-time solutions to complex problems at a blazing speed. Bat algorithm evolved the optimised fuzzy model within a few seconds as compared to other approaches.
A performance management model addressing human factors in the North West provincial administration
Authors: Klinck Kezell , Swanepoel Sonia
Published: February 2019

Orientation: The article investigated factors from several perspectives using human resources-related issues of governance, legislation, regulation, organisation, administration and communication, workplace sociology variables pertaining to social and psychological relationships and several other factors that have an impact on the complex matrix of determinants for performance improvement in the public service.Research purpose: This article explored the human factors linked to the performance management (PM) processes and its impact on the effectiveness of service delivery in the North West provincial administration (NWPA). The article isolated the strengths and weaknesses of the system of performance assessment from the human relations perspective, technical usage, the structural–organisational and the strategic perspectives, uniformity, legislative compliance and other possibilities envisaged and emerging.Motivation for the study: The study would deliver a successful and carefully crafted PM model that could be used to remedy the current performance situation through improved and effective communication channels, as well as ongoing feedback, leading to a more productive and motivated workforce. This would ultimately yield improved service delivery for the citizens of the North West Province.Research approach/design and method: To answer the main research questions, sub-questions and objectives of this study, several participants (permanent employees and managers) found in the departments within the NWPA had to respond to diverse instruments of inquiry (questionnaires, interview schedules, expert, operational, strategic and grass-roots opinion, etc.). The study took a sequential mixed-methods approach where interpretivist (qualitative) and positivist (quantitative) approaches were applied as the philosophy and descriptive statistics were used.Main findings: The main findings highlighted all the human factors that mitigated against performance improvement in the NWPA. From the evidence gathered, some departments exhibited problematic manager–subordinate relationships, lack of training, no proper feedback, low staff morale leading to low job satisfaction, lack of leadership as well as broken channels of communication.Practical/managerial implications: The findings revealed that it is important for the NWPA management to undertake the necessary efforts in order to adapt a new strategy and comprehensive model for improved performance, which would ultimately lead towards efficient and effective service delivery in the North West Province.Contribution/value-add: This paper explores the salient human factors to be taken into consideration during performance management in the North West Provincial Administration.
Constituição e Política na Venezuela: Um balanço da conjuntura contemporânea
Authors: Bello Enzo
Published: February 2019

O presente texto analisa as relações entre Constituição e Política na Venezuela na conjuntura contemporânea: início do governo do presidente Nicolas Maduro, em 2013, até a instalação da Assembleia Nacional Constituinte, em 2017, e a convocação de eleições presidenciais, em 2018. Seu principal objetivo é expor e analisar a dinâmica constitucional em um processo político conturbado e peculiar, no qual são disputadas as noções de Constituição, Estado de Direito e legalidade. A metodologia envolve pesquisa interdisciplinar com orientação epistemológica na teoria crítica, congregando teoria e práxis, articulando Direito e Política. O texto adota os raciocínios indutivo e dedutivo, em pesquisa qualitativa com as técnicas de análise documental e revisão bibliográfica. As fontes de pesquisa são predominantemente de origem venezuelana e subsidiariamente latino-americanas e brasileiras. As primárias são dados de órgãos oficiais, jornais, blogs e periódicos. As secundárias são documentos normativos, artigos e livros acadêmicos.
A proxy for atmospheric daytime gaseous sulfuric acid concentration in urban Beijing
Authors: Lu Yiqun , Yan Chao , Fu Yueyun , Chen Yan , Liu Yiliang , Yang Gan , Wang Yuwei , Bianchi Federico , Chu Biwu , Zhou Ying , Yin Rujing , Baalbaki Rima , Garmash Olga , Deng Chenjuan , Wang Weigang , Liu Yongchun , Petäjä Tuukka , Kerminen Veli-Matti , Jiang Jingkun , Kulmala Markku , Wang Lin
Published: February 2019

Abstract. Gaseous sulfuric acid (H2SO4) is known as one of
the key precursors for atmospheric new particle formation (NPF) processes,
but its measurement remains challenging. Therefore, a proxy method that is
able to derive gaseous sulfuric acid concentrations from parameters that can
be measured relatively easily and accurately is highly desirable for the
atmospheric chemistry community. Although such methods are available for
clean atmospheric environments, a proxy that works well in a polluted
atmosphere, such as that found in Chinese megacities, is yet to be developed.
In this study, the gaseous sulfuric acid concentration was measured in
February–March 2018, in urban Beijing using a nitrate based – long
time-of-flight chemical ionization mass spectrometer (LToF-CIMS). A number of
atmospheric parameters were recorded concurrently including the ultraviolet
radiation B (UVB) intensity, the concentrations of O3,
NOx (sum of NO and NO2), SO2, and HONO,
and aerosol particle number size distributions. A proxy for atmospheric
daytime gaseous sulfuric acid concentration was derived via a statistical
analysis method using the UVB intensity, [SO2], the condensation
sink (CS), [O3], and [HONO] (or [NOx]) as the
predictor variables, where square brackets denote the concentrations of the corresponding species.
In this proxy method, we considered the formation of gaseous sulfuric acid from reactions
of SO2 and OH radicals during the daytime, and the loss of gaseous
sulfuric acid due to its condensation onto the preexisting particles. In
addition, we explored the formation of OH radicals from the conventional
gas-phase photochemistry using O3 as a proxy and from the
photolysis of HONO using HONO (and subsequently NOx) as a
proxy. Our results showed that the UVB intensity and [SO2] are
dominant factors in the production of gaseous sulfuric acid, and that the
simplest proxy could be constructed with the UVB intensity and
[SO2] alone. When the OH radical production from both homogenously
and heterogeneously formed precursors were considered, the relative errors
were reduced by up to 20 %.
Interactions between the atmosphere, cryosphere, and ecosystems at northern high latitudes
Authors: Boy Michael , Thomson Erik S. , Acosta Navarro Juan-C. , Arnalds Olafur , Batchvarova Ekaterina , Bäck Jaana , Berninger Frank , Bilde Merete , Brasseur Zoé , Dagsson-Waldhauserova Pavla , Castarède Dimitri , Dalirian Maryam , de Leeuw Gerrit , Dragosics Monika , Duplissy Ella-Maria , Duplissy Jonathan , Ekman Annica M. L. , Fang Keyan , Gallet Jean-Charles , Glasius Marianne , Gryning Sven-Erik , Grythe Henrik , Hansson Hans-Christen , Hansson Margareta , Isaksson Elisabeth , Iversen Trond , Jonsdottir Ingibjorg , Kasurinen Ville , Kirkevåg Alf , Korhola Atte , Krejci Radovan , Kristjansson Jon Egill , Lappalainen Hanna K. , Lauri Antti , Leppäranta Matti , Lihavainen Heikki , Makkonen Risto , Massling Andreas , Meinander Outi , Nilsson E. Douglas , Olafsson Haraldur , Pettersson Jan B. C. , Prisle Nønne L. , Riipinen Ilona , Roldin Pontus , Ruppel Meri , Salter Matthew , Sand Maria , Seland Øyvind , Seppä Heikki , Skov Henrik , Soares Joana , Stohl Andreas , Ström Johan , Svensson Jonas , Swietlicki Erik , Tabakova Ksenia , Thorsteinsson Throstur , Virkkula Aki , Weyhenmeyer Gesa A. , Wu Yusheng , Zieger Paul , Kulmala Markku
Published: February 2019

Abstract. The Nordic Centre of Excellence CRAICC (Cryosphere–Atmosphere Interactions
in a Changing Arctic Climate), funded by NordForsk in the years 2011–2016,
is the largest joint Nordic research and innovation initiative to date,
aiming to strengthen research and innovation regarding climate change issues
in the Nordic region. CRAICC gathered more than 100 scientists from all
Nordic countries in a virtual centre with the objectives of identifying and
quantifying the major processes controlling Arctic warming and related feedback
mechanisms, outlining strategies to mitigate Arctic warming, and developing
Nordic Earth system modelling with a focus on short-lived climate
forcers (SLCFs), including natural and anthropogenic aerosols. The outcome of CRAICC is reflected in more than 150 peer-reviewed scientific
publications, most of which are in the CRAICC special issue of the journal
Atmospheric Chemistry and Physics. This paper presents an overview
of the main scientific topics investigated in the centre and provides the
reader with a state-of-the-art comprehensive summary of what has been achieved in
CRAICC with links to the particular publications for further detail. Faced
with a vast amount of scientific discovery, we do not claim to completely
summarize the results from CRAICC within this paper, but rather
concentrate here on the main results which are related to feedback loops in
climate change–cryosphere interactions that affect Arctic amplification.