bluuebunny/crossref_metadata_2025 huggingface dataset:
Tidal Disruption Events: The Role of Stellar Spin
Authors: Golightly Elen C. A. , Coughlin Eric R. , Nixon C. J.
Published: February 2019

The tidal force from a supermassive black hole can rip apart a star that passes close enough in what is known as a Tidal Disruption Event (TDE). Typically, half of the destroyed star remains bound to the black hole and falls back on highly eccentric orbits, forming an accretion flow that powers a luminous flare. In this paper, we use analytical and numerical calculations to explore the effect of stellar rotation on the fallback rate of material. We find that slowly spinning stars (Ω* ≲ 0.01Ωbreakup) provide only a small perturbation to fallback rates found in the non-spinning case. However, when the star spins faster, there can be significant effects. If the star is spinning retrograde with respect to its orbit, the tidal force from the black hole has to spin down the star first before disrupting it, causing delayed and sometimes only partial disruption events. However, if the star is spinning prograde, this works with the tidal force and the material falls back sooner and with a higher peak rate. We examine the power-law index of the fallback curves, finding that in all cases the fallback rate overshoots the canonical t
−5/3 rate briefly after the peak, with the depth of the overshoot dependent on the stellar spin. We also find that, in general, the late time evolution is slightly flatter than the canonical t
−5/3 rate. We therefore conclude that considering the spin of the star may be important in modeling observed TDE light curves.
IQ-Collaboratory 1.1: The Star-forming Sequence of Simulated Central Galaxies
Authors: Hahn ChangHoon , Starkenburg Tjitske K. , Choi Ena , Davé Romeel , Dickey Claire M. , Geha Marla C. , Genel Shy , Hayward Christopher C. , Maller Ariyeh H. , Mandyam Nityasri , Pandya Viraj , Popping Gergö , Rafieferantsoa Mika , Somerville Rachel S. , Tinker Jeremy L.
Published: February 2019

A tightly correlated star formation rate (SFR)–stellar mass relation of star-forming galaxies, or star-forming sequence (SFS), is a key feature in galaxy property-space that is predicted by modern galaxy formation models. We present a flexible data-driven approach for identifying this SFS over a wide range of SFRs and stellar masses using Gaussian mixture modeling (GMM). Using this method, we present a consistent comparison of the z = 0 SFSs of central galaxies in the Illustris, Evolution and Assembly of GaLaxies and their Environment, and Mufasa hydrodynamic simulations and the Santa Cruz semianalytic model (SC-SAM), alongside data from the Sloan Digital Sky Survey. We find, surprisingly, that the amplitude of the SFS varies by up to ∼0.7 dex (factor of ∼5) among the simulations with power-law slopes ranging from 0.7 to 1.2. In addition to the SFS, our GMM method also identifies subcomponents in the SFR–stellar mass plane corresponding to starburst, transitioning, and quiescent subpopulations. The hydrodynamic simulations are similarly dominated by SFS and quiescent subpopulations unlike the SC-SAM, which predicts substantial fractions of transitioning and starburst galaxies at stellar masses above and below

, respectively. All of the simulations also produce an abundance of low mass quiescent central galaxies in apparent tension with observations. These results illustrate that, even among models that well reproduce many observables of the galaxy population, the z = 0 SFS and other subpopulations still show marked differences that can provide strong constraints on galaxy formation models.
An Asymmetric Keplerian Disk Surrounding the O-type Protostar IRAS 16547−4247
Authors: Zapata Luis A. , Garay Guido , Palau Aina , Rodríguez Luis F. , Fernández-López Manuel , Estalella Robert , Guzmán Andres
Published: February 2019

For the past few decades, there has been great interest in determining if even the most massive stars in our galaxy (namely the spectral O-type stars) are formed in a similar manner as the low- and intermediate-mass stars, that is, through the presence of accreting disks and powerful outflows. Here, using sensitive observations of the Atacama Large Millimeter/Submillimeter Array, we report a resolved Keplerian disk (with 15 synthesized beams across its major axis) surrounding the deeply embedded O-type protostar IRAS 16547−4247. The disk shows some asymmetries that could arise because the disk is unstable and fragmenting or because of different excitation conditions within the disk. The enclosed mass estimated from the disk Keplerian radial velocities is 25 ± 3 M
⊙. The molecular disk is at the base of an ionized thermal radio jet and is approximately perpendicular to the jet axis orientation. We additionally find the existence of a binary system of compact dusty objects at the center of the accreting disk, which indicates the possible formation of an O-type star and a companion of lower mass. This is not surprising due to the high binary fraction reported in massive stars. Subtracting the contribution of the dusty disk plus the envelope and the companion, we estimated a mass of 20 M
⊙ for the central star.
The Rotation-disk Connection in Young Brown Dwarfs: Strong Evidence for Early Rotational Braking
Authors: Moore Keavin , Scholz Aleks , Jayawardhana Ray
Published: February 2019

We use Kepler/K2 light curves to measure rotation periods of brown dwarfs and very low mass stars in the Upper Scorpius star-forming region. Our sample comprises a total of 104 periods. Depending on the assumed age of Upper Scorpius, about a third of them are for brown dwarfs. The median period is 1.28 day for the full sample and 0.84 day for the probable brown dwarfs. With this period sample, we find compelling evidence for early rotational braking in brown dwarfs, caused by the interaction between the central object and the disk. The median period for objects with disks is at least 50% longer than for those without. Two brown dwarfs show direct signs of “disk-locking” in their light curves, in the form of dips that recur on a timescale similar to the rotation period. Comparing the period samples for brown dwarfs at different ages, there is a clear need to include rotational braking into period evolution tracks between 1 and 10 Myr. A locked period over several Myr followed by spin-up due to contraction fits the observational data. We conclude that young brown dwarfs are affected by the same rotational regulation as stars, though they start off with significantly faster rotation, presumably set by initial conditions.
Asteroseismology of the Pre-main-sequence δ Scuti Pulsator IP Persei
Authors: Chen Xinghao , Li Yan
Published: February 2019

A grid of theoretical models are computed to fit the nine oscillation modes of IP Per detected earlier from a multi-site ground-based campaign. Fitting results show that there are two sets of theoretical models that could reproduce the observed frequencies more or less equally as well. In view of other available spectroscopic and photometric measurements, our best-fitting stellar parameters for IP Per are

km s−1,

,

M
⊙,

K,

,

dex,

R
⊙,

s, and age = 

Myr. Meanwhile, IP Per is found to be a pre-main-sequence star where the CN cycle has not yet reached the equilibrium state. At present, 14% of C12 have been turned into N14. Based on the best-fitting model, f
6 is identified as a radial mode, f
1 and f
2 as two dipole modes, and f
3, f
4, f
5, f
7, f
8, and f
9 as six quadrupole modes.
Effects of Rotation and Magnetic Field on the Revival of a Stalled Shock in Supernova Explosions
Authors: Fujisawa Kotaro , Okawa Hirotada , Yamamoto Yu , Yamada Shoichi
Published: February 2019

We investigate axisymmetric steady solutions of (magneto)hydrodynamics equations that approximately describe accretion flows through a standing shock wave onto a protoneutron star and discuss the effects of rotation and magnetic field on the revival of the stalled shock wave in supernova explosions. We develop a new powerful numerical method to calculate the two-dimensional steady accretion flows self-consistently. We first confirm the results of preceding papers that there is a critical luminosity of irradiating neutrinos, above which there exists no steady solution in spherical models. If a collapsing star is rotating and/or has a magnetic field, the accretion flows are no longer spherical owing to the centrifugal force and/or Lorentz force, and the critical luminosity is modified. In fact, we find that the critical luminosity is reduced by about 50%–70% for very rapid rotations; the rotation frequencies are 0.2–0.45 s−1 at the radius of r = 1000 km (equivalent to spin periods ∼0.5–0.22 ms at r = 10 km) and about 20%–50% for strong toroidal magnetic fields (the strengths of which are 1.0 × 1012–3.0 × 1012 G at r = 1000 km), depending on the mass accretion rate. These results may also be interpreted as the existence of a critical specific angular momentum or critical magnetic field, above which there exists no steady solution and the standing shock wave will be revived for a given combination of mass accretion rate and neutrino luminosity.
Removal of Spectro-polarimetric Fringes by Two-dimensional Principal Component Analysis
Authors: Casini R. , Li W.
Published: February 2019

We investigate the application of two-dimensional Principal Component Analysis (2D PCA) to the problem of removal of polarization fringes from spectro-polarimetric data sets. We show how the transformation of the PCA basis through a series of carefully chosen rotations allows us to confine polarization fringes (and other stationary instrumental effects) to a reduced set of basis “vectors,” which at the same time are largely devoid of the spectral signal from the observed target. It is possible to devise algorithms for the determination of the optimal series of rotations of the PCA basis, thus opening the possibility of automating the procedure of defringing of spectro-polarimetric data sets. We compare the performance of the proposed method with the more traditional Fourier filtering of Stokes spectra.
Big Bang Nucleosynthesis with an Inhomogeneous Primordial Magnetic Field Strength
Authors: Luo Yudong , Kajino Toshitaka , Kusakabe Motohiko , Mathews Grant J.
Published: February 2019

We investigate the effect on the Big Bang nucleosynthesis (BBN) from the presence of a stochastic primordial magnetic field (PMF) whose strength is spatially inhomogeneous. We assume a uniform total energy density and a Gaussian distribution of field strength. In this case, domains of different temperatures exist in the BBN epoch due to variations in the local PMF. We show that in such a case, the effective distribution function of particle velocities averaged over domains of different temperatures deviates from the Maxwell–Boltzmann distribution. This deviation is related to the scale invariant strength of the PMF energy density ρ
Bc and the fluctuation parameter σ
B. We perform BBN network calculations taking into account the PMF strength distribution and deduce the element abundances as functions of the baryon-to-photon ratio η, ρ
Bc, and σ
B. We find that the fluctuations of the PMF reduce the 7Be production and enhance D production. We analyze the averaged thermonuclear reaction rates compared with those of a single temperature and find that the averaged charged-particle reaction rates are very different. Finally, we constrain the parameters ρ
Bc and σ
B from observed abundances of 4He and D and find that the 7Li abundance is significantly reduced. We also find that if the η value during BBN was larger than the present-day value due to a dissipation of the PMF or a radiative decay of exotic particles after BBN or if the stellar depletion of 7Li occurred, abundances of all light elements can be consistent with observational constraints.
Multi-wavelength Properties of Type 1 and Type 2 AGN Host Galaxies in the Chandra-COSMOS Legacy Survey
Authors: Suh Hyewon , Civano Francesca , Hasinger Günther , Lusso Elisabeta , Marchesi Stefano , Schulze Andreas , Onodera Masato , Rosario David J. , Sanders David B.
Published: February 2019

We investigate the multi-wavelength properties of host galaxies of 3701 X-ray-selected active galactic nuclei (AGNs) out to z ∼ 5 in the Chandra-COSMOS Legacy Survey. Thanks to the extensive multi-wavelength photometry available in the COSMOS field, we derive AGN luminosities, host stellar masses, and star formation rates (SFRs) via a multi-component SED fitting technique. Type 1 and Type 2 AGNs follow the same intrinsic L
2–10 keV–L
6 μm relation, suggesting that mid-infrared emission is a reasonably good measure of the AGN accretion power regardless of obscuration. We find that there is a strong increase in Type 1 AGN fraction toward higher AGN luminosity, possibly due to the fact that Type 1 AGNs tend to be hosted by more massive galaxies. The AGN luminosity and SFR are consistent with an increase toward high stellar mass, while the M
stellar dependence is weaker toward the high-mass end, which could be interpreted as a consequence of quenching both star formation and AGN activity in massive galaxies. AGN host galaxies tend to have SFRs that are consistent with normal star-forming galaxies, independent of AGN luminosities. We confirm that black hole accretion rate and SFR are correlated up to z ∼ 5, when forming stars. The majority (∼73%) of our AGN sample are faint in the far-infrared, implying that the moderate-luminosity AGNs seem to be still active after the star formation is suppressed. It is not certain whether AGN activity plays a role in quenching the star formation. We conclude that both AGN activity and star formation might be more fundamentally related to host stellar mass.
The Large-scale Magnetic Field of a Thin Accretion Disk with Outflows
Authors: Li Jiawen , Cao Xinwu
Published: February 2019

The large-scale magnetic field threading an accretion disk plays an important role in launching jets/outflows. The field may probably be advected inward by the plasma in the accretion disk from the ambient environment (interstellar medium or a companion star). It has been suggested that the external field can be efficiently dragged inward in a thin disk with magnetic outflows. We construct a self-consistent global disk-outflow model in which the large-scale field is formed by the advection of the external field in the disk. The outflows are accelerated by this field corotating with the disk, which carries away most of the angular momentum of the disk and causes its structure to become significantly different from the conventional viscous disk structure. We find that the magnetic field strength in the inner region of the disk can be several orders of magnitude higher than the external field strength for a geometrically thin disk with H/R ∼0.1 if the ratio of the gas to magnetic pressure β
out ∼ 102 at the outer edge of the disk. The outflow velocity shows a layer-like structure, i.e., it decreases with radius where it is launched. The outflow can be accelerated up to ∼0.2–0.3c from the inner region of the disk, and the mass-loss rate in the outflows is ∼10%–70% of the mass accretion rate at the outer radius of the disk, which may account for the fast outflows that are observed in some active galactic nuclei.
Internal Gravity Waves in the Magnetized Solar Atmosphere. II. Energy Transport
Authors: Vigeesh G. , Roth M. , Steiner O. , Jackiewicz J.
Published: February 2019

In this second paper of the series on internal gravity waves (IGWs), we present a study of the generation and propagation of IGWs in a model solar atmosphere with diverse magnetic conditions. A magnetic field-free and three magnetic models that start with an initial, vertical, homogeneous field of 10, 50, and 100 G magnetic flux density, are simulated using the CO5BOLD code. We find that the IGWs are generated in similar manner in all four models in spite of the differences in the magnetic environment. The mechanical energy carried by IGWs is significantly larger than that of the acoustic waves in the lower part of the atmosphere, making them an important component of the total wave energy budget. The mechanical energy flux (106–103 W m−2) is a few orders of magnitude larger than the Poynting flux (103–101 W m−2). The Poynting fluxes show a downward component in the frequency range corresponding to the IGWs, which confirm that these waves do not propagate upward in the atmosphere when the fields are predominantly vertical and strong. We conclude that, in the upper photosphere, the propagation properties of IGWs depend on the average magnetic field strength and therefore these waves can be potential candidates for magnetic field diagnostics of these layers. However, their subsequent coupling to Alfvénic waves is unlikely in a magnetic environment permeated with predominantly vertical fields, and therefore they may not directly or indirectly contribute to the heating of layers above plasma-β less than 1.
In Search of the Thermal Eccentricity Distribution
Authors: Geller Aaron M. , Leigh Nathan W. C. , Giersz Mirek , Kremer Kyle , Rasio Frederic A.
Published: February 2019

About a century ago, Jeans (1919) discovered that if binary stars reach a state approximating energy equipartition, for example, through many dynamical encounters that exchange energy, their eccentricity distribution can be described by

. This is referred to as the thermal eccentricity distribution, and has been widely used for initial conditions in theoretical investigations of binary stars. However, observations suggest that the eccentricity distributions of most observed binaries, and particularly those with masses ≲5 M
⊙, are flatter than thermal and follow more closely to a uniform distribution. Nonetheless, it is often argued that dynamical interactions in a star cluster would quickly thermalize the binaries, which could justify imposing a thermal eccentricity distribution at birth for all binaries. In this paper, we investigate the validity of this assumption. We develop our own rapid semi-analytic model for binary evolution in star clusters, and also compare it with detailed N-body and Monte Carlo star cluster models. We show that, for nearly all binaries, dynamical encounters fail to convert an initially uniform eccentricity distribution to thermal within a star cluster’s lifetime. Thus, if a thermal eccentricity distribution is observed, it is likely imprinted upon formation rather than through subsequent long-term dynamical processing. Theoretical investigations that initialize all binaries with a thermal distribution will make incorrect predictions for the evolution of the binary population. Such models may overpredict the merger rate for binaries with modest orbital separations by a factor of about two.
Surveys of Clumps, Cores, and Condensations in Cygnus X. I. A New Catalog of ∼0.1 pc Massive Dense Cores
Authors: Cao 曹 Yue 越 , Qiu Keping , Zhang Qizhou , Wang Yuwei , Hu Bo , Liu Junhao
Published: February 2019

Using infrared to (sub)millimeter data from Spitzer, Herschel, the James Clerk Maxwell Telescope, and the IRAM 30 m telescope, we conducted an unbiased survey of the massive dense cores (MDCs) in the Cygnus X molecular cloud complex, aimed at characterizing the physical conditions of high-mass star formation (HMSF) at ∼0.1 pc scales. We created 5° × 6° images of the 70–1200 μm dust continuum, gas column density, and dust temperature of Cygnus X. A spatial relation between the dense regions (A
v ≥ 15) and the developed H ii regions was found, indicating the impact of the latter on the global structures of Cygnus X. With a 35 M
⊙ mass threshold implied by HMSF signposts, we identified 151 MDCs with sizes of ∼0.1 pc, masses of 35–1762 M
⊙, and temperatures of 8–35 K. Our MDC sample is statistically complete in Cygnus X and is three times larger than that in Motte et al. The MDCs were classified into IR-bright/IR-quiet ones based on their midinfrared fluxes, and a large “IR-quiet” proportion (90%) was found in our sample. Two possible scenarios were proposed to interpret accelerated HMSF and the incapability of HMSF of the IR-quiet MDCs. We also found 26 starless MDCs by their lack of compact emissions at 21–70 μm wavelengths, of which the most massive ones are probably the best candidates of initial HMSF sites in Cygnus X.
Reference DNA barcodes and other mitochondrial markers for identifying Caribbean Octocorals
Authors: Morín Jaime , Venera-Pontón Dagoberto , Driskell Amy , Sánchez Juan , Lasker Howard , Collin Rachel
Published: February 2019

DNA barcoding is a useful tool for documenting the diversity of metazoans. The most commonly used barcode markers, 16S and COI, are not considered suitable for species identification within some "basal" phyla of metazoans. Nevertheless metabarcoding studies of bulk mixed samples commonly use these markers and may obtain sequences for "basal" phyla. We sequenced mitochondrial DNA fragments of cytochrome oxidase c subunit I (COI), 16S ribosomal RNA (16S), NADH dehydrogenase subunits 2 (16S-ND2), 6 (ND6-ND3) and 4L (ND4L-MSH) for 27 species of Caribbean octocorals to create a reference barcode dataset and to compare the utility of COI and 16S to other markers more typically used for octocorals. The most common genera (Erythropodium, Ellisella, Briareum, Plexaurella, Muriceopsis and Pterogorgia) were effectively distinguished by small differences (5 or more substitutions or indels) in COI and 16S sequences. Gorgonia and Antillogorgia were effectively distinguished from each other by unique haplotypes, but the small genetic differences make distance approaches ineffective for these taxa. Plexaura, Pseudoplexaura and Eunicea were indistinguishable from each other but were generally effectively distinguished from other genera, further supporting the idea that these genera have undergone a rapid endemic radiation in the Caribbean.
Phylogeny and taxonomy of three new Ctenomyces (Arthrodermataceae, Onygenales) species from China
Authors: Zhang Zhi-Yuan , Han Yan-Feng , Chen Wan-Hao , Liang Zong-Qi
Published: February 2019

Twelve Ctenomyces (Arthrodermataceae, Onygenales) strains were obtained and identified during a survey of keratinophilic fungi in soils from China. We used molecular identification combined with morphological evidence to delimit species, circumscribing five species in the genus. Three new species are herein described: C.albussp. nov., C.obovatussp. nov. and C.peltricolorsp. nov. We also described, illustrated and compared the novel species with related species in the morphology.
Monetary Value Change of Some Provisioning Ecosystem Services of Middle Draa Valley, South of Morocco
Authors: Zerouali Siham , Yacoubi-Khebiza Mohammed , El Qorchi Fadoua
Published: February 2019

The desert oasis is a wetland agro-ecosystem more and more under pressure. This trend threatens the oasis ecosystem services (ES) and then the wellbeing of the local population. In order to quantify this trend in Middle Draa Valley, South of Morocco, the monetary values for a selection of ES have been estimated. In this chapter, the economic values of 28 provisioning ES in 2014 was examined and next compared with the economic values of 2009. These values were standardized to US$ per hectare per year. The total value of the studied provisioning ES in 2014 was found to be 8658.3 US$/ha/year for the arable area (26000ha) and 150 US$/ha/year for the whole Middle Draa Valley (1500000ha). Comparing these findings with the data of 2009, a slight increase of $1245.7 (in 26000ha) and $21.5 US$/ha/year (the whole area) was detected in the period 2009-2014.
Potential Impacts of Climate Change on Land Degradation and Desertification
Authors: Dharumarajan S.  , Veeramani S.  , Beeman Kalaiselvi , Lalitha M.  , Janani N.  , Srinivasan R.  , Hegde Rajendra
Published: February 2019

Land degradation and desertification have been graded as a major environmental and social dispute in most of the emerging countries. Changes in temperature, wind speed, and precipitation patterns will influence plant biomass production, land use, land cover, soil moisture, infiltration rate, runoff and crop management, and ultimately, land degradation. Close relations between climate change and land degradation processes have been perceived in the past decades. Climate change models and land use models should be combined with hydrologic/erosion models to accurately compute or predict climate change impacts on land degradation. This chapter introduces the advancements in modeling of impact of climate changes in land degradation and need for the critical investigation to better understand and forecast the responses of land degradation processes to a changing climate in the future.
Preliminary Sizing and Performance Calculations of Unmanned Air Vehicles
Authors: Dinc Ali
Published: February 2019

In this chapter, preliminary sizing and performance calculations of unmanned air vehicles (UAV), with relation to its propulsion system, are explained. Starting with the mission profile of the air vehicle, which is one of the important design drivers, the UAV is sized for the requirements. The requirements in design consist of a set of target values (e.g., payload amount to be carried, range, endurance time, cost, etc.). Additionally, the parameters within mission profile such as cruising altitude and speed of aircraft affect engine type, power level required, fuel quantity, and therefore general dimensions and the gross weight of the aircraft. It is often an iterative process to size the air vehicle and engine together. UAV is designed in a loop of calculations in which sizing, flight performance, and engine performance are done for each phase of the mission or flight profile to satisfy the overall design mission and requirements.
Unmanned Aerial Vehicle Applications for Military GIS Task Solutions
Authors: Bayramov Azad Agalar , Hashimov Elshan Giyas , Nasibov Yashar Ali
Published: February 2019

In the chapter, the authors present the results of unmanned aerial vehicle (UAV) applications for military geoinformation system (GIS) task solutions. The results of the visual modelling of the revealing process of invisible military objects from one of point of observation on the mountainous terrain of the Azerbaijan Republic by using UAV are presented. The observation conditions between two points of the selected mountain terrain during battle operation have been investigated using GIS technology. The quantitative method of the invisible area assessment and military objects in mountainous terrain are developed and offered by using UAVs. The numerical estimation method of a task support success of UAV reconnaissance flight in mountainous battle conditions has been offered and considered. Using UAVs for the purpose of orthophotomap making of the terrain and combat control the detailed 3D-model has been constructed.
Social Capital and Innovation
Authors: Murphy Lyndon John
Published: February 2019

There is a considerable body of literature available to aid understanding of the concept of social capital and the identification of its presence. Overall objectives and mission of the chapter are to compile an up-to-date and academically grounded study providing a theoretical perspective taking into consideration the theories, concepts and processes in the area of social capital and innovation. The methodology used involves the construction of a conceptual framework regarding theories, concepts and processes. This involved a thematic analysis of social capital, innovation, and related concepts. The qualitative method for building the conceptual framework involved phenomena linked to the multidisciplinary body of work in the areas of social capital and innovation. The potential contribution of the chapter has been to bring together findings on the facets of social capital which are generally acknowledged to include trust, collaboration, cooperation, as well as bridging and bonding social network ties, and reciprocity, in terms of innovation.
Organizational Ecosystems
Authors: Thomas Brychan Celfyn
Published: February 2019

The aim of this chapter is to compile an up-to-date and academically grounded study into organizational ecosystems in terms of innovation and social capital dimensions. The authors are concerned with the dimensions of innovation involving traditionally measured forms of innovation, hidden innovation and social innovation, and social capital including collaboration, cooperation, as well as bridging and bonding social capital and network ties. The methodology used involved systems model formulation following the stages of the identification of the main structures, relationships and components, model building, development of an evolved organizational ecosystem model, and analysis of the model. The research question addressed the question, What are the main components of organizational ecosystems in terms of innovation and social capital dimensions? The contribution of the chapter is to bring together findings on the characteristics of organizational ecosystems in terms of the dimensions of innovation, and social capital including trust, collaboration, cooperation, and social network ties.
Social Capital and Innovation Performance in Firms
Authors: Abdulai Abdul-Fatahi
Published: February 2019

This chapter contributes to the debate on the conceptual differences and disparities in the definitions of social capital among researchers. It also delves into the potential influence of social capital on innovation performance of firms, which continues to fuel its misunderstanding in the literature. The study critically reviews, discusses and presents available literature on the concept of social capital and its subsequent influence on innovation performance. The methodology is an extensive review of available literature on the concepts and the possible link between them. The investigation provides a potential contribution to the debate on the relationship between social capital and innovation performance in firms as a way of direction and attempts to synthesize what academia considers with regard to the concepts and points out potential areas of research required to develop the overall subject area. The chapter offers a resource for practitioners and students in this new field which has attracted the attention of enterprise developers.
The Movement of Senior Staff and Their Competencies Between Enterprises in a High Technology Cluster
Authors: Thomas Brychan Celfyn
Published: February 2019

The purpose of this chapter is to investigate the movement of senior staff and their competencies between enterprises in a high technology cluster (HTC). An analysis has been undertaken of the movement of senior staff between high technology enterprises. The mobility of senior staff in the cluster is considered with reference to the growth of the cluster. The findings of the research show that a local production network exists around cluster enterprises. An extensive knowledge network has been built around the enterprises facilitated by senior staff movement between them. Here it has been found that knowledge diffused by the mobility of labor involving senior staff in the high technology cluster has contributed to the cluster performing better through the generation of spinouts and the accumulation of knowledge. The approach highlights the importance of the movement of labor between enterprises in a high technology cluster in terms of understanding cluster growth dynamics and the cluster's contribution and importance to international industry.
Earnings Management and Corporate Governance in Family Firms
Authors: Vieira Elisabete , Madaleno Mara
Published: February 2019

Earnings management and corporate governance relationships are examined for a sample of 49 Portuguese listed firms considering an unbalanced panel for the period 2002-2017, using panel corrected standard errors models and considering the family ownership effect. Empirical findings reveal that there is a positive relationship between corporate board independence and earnings management and that the presence of women on board decreases earnings management practices. Results are consistent with the hypothesis that earnings management practices are lower in family firms than in non-family firms. Size, being audited by the Big 4 companies, return on assets, loss, and the existence of an audit committee on board influence positively earnings management, but leverage, age, and ownership control are negatively related to earnings management. Results indicate that further auditing and control is necessary for Portuguese listed companies leading to strict recommendations to be followed by policymakers regarding control of these firms.
The Relationship Between the Quality of Financial Information in Industrial Companies and Discretionary Inventory Management
Authors: Nogueira Maria Filipa
Published: February 2019

Inventories are the base element for the manufacturing (industrial) companies. The inclusion of discretionary in the inventory management processes of production leads to changes in the value of the companies. The accounting system produces information used in predictions and for management decision. The usefulness and opportunity of information are considered indispensable. If managers use their discretionarily, in the accounting system and in real activities, to achieve the firm value and earnings forecast, they will influence and modify the financial information quality. Ferrer and Ferrer said that a simple decision can enrich one company from one moment to another, and a small accounting change allows a great loss of results. The question arises: Do managers use their discretionarily and modify the financial information quality? Using adjusted models to capture discretionary accounting management and real activity management, it is possible to conclude that there is a strong evidence of discretionary management of the inventory in manufacturing Portuguese SME.
Determinants of the Readability and Comprehensibility of Risk Disclosures
Authors: Oliveira Jonas da Silva , Azevedo Graça Maria do Carmo , Ferreira Augusta da Conceição Santos , Martins Susana Patrícia Henriques , Pinto Cláudia Roberta de Araújo Alves
Published: February 2019

The chapter intends to determine if managers make use of impression management strategies to hide or obfuscate risk disclosures through the analyses of the risk information disclosed by Portuguese non-financial listed companies. A content analysis of the management reports, notes to the financial statements, and corporate governance reports of companies listed at Euronext Lisbon, in the years 2007, 2010, and 2013 was carried out. Findings indicate that the understandability of the risk information is positively associated with the company's size. Results also indicate that there is a negative association between the readability of risk information disclosed and the company's size and industry.
The Use of Financial Graphics as an Impression Management Tool
Authors: Azevedo Graça Maria do Carmo , Oliveira Jonas da Silva , Ferreira Augusta da Conceição Santos , Dias Sara Raquel Pinto Marcelino
Published: February 2019

The main objective of this chapter is to determine the graph discrepancy index and to analyze which factors can actually influence the graphical discrepancy index, based on the strategies of impression management. For this particular purpose, a content analysis of management and financial reports was made, from 2010 to 2015, of Portuguese companies with securities admitted to trading in Euronext Lisbon. Findings indicate that companies tend to engage in printing management practices, but it was not possible to identify the determinants of such practices since all the hypotheses were rejected.
IoT Platforms and Technologies Driving Spatial Planning and Analytics
Authors: Bottaccioli Lorenzo , Patti Edoardo , Osello Anna , Cerquitelli Tania , Macii Enrico , Acquaviva Andrea
Published: February 2019

The continuous evolution of internet of things technologies is constantly evolving the concept of smart cities as well as the surrounding environments. From pervasive sensors through computational nodes at the edge of the network to the cloud and final user applications, the data flow chain makes available to the user a very large and heterogeneous amount of data. IoT platforms are at the core of this chain, providing seamless access to data independently from the hardware devices and making possible the interoperability with other data sources (e.g., GIS, SIM, etc.). Despite the availability of IoT platform solutions either commercial and open-source, research is still very active to design and implement flexible, easy-to-use, and efficient web-service-oriented software infrastructures. This chapter will review the current IoT platform infrastructures making also reference to state-of-the-art solutions in literature and proposed in recent research projects. The chapter will outline the main challenges and directions about future platforms, putting them in the context of realistic case studies.
The Walkability of the Cities
Authors: La Riccia Luigi , Cittadino Antonio , Fiermonte Francesco , Garnero Gabriele , Guerreschi Paola , Vico Franco
Published: February 2019

The issue of city walkability is nowadays a theme in evidence. The chapter proposes a two-level reasoning. At the city level, the goal is to recognize the parts where actions aimed at improving walkability can be more effective. The second level is more detailed: lacking pedestrian paths' specific graphs, the urban space is modeled through a raster with 1x1 m. cells. Considering a series of criteria, an impedance has been assigned to each cell (i.e., the cost of travelling the cell on foot). This approach is applied to the city of Torino (Italy), but it is largely generalizable. To calculate this impedance, inter alia, the Torino geo-topographic database was used. The elaborations described in this chapter are seen as an aid to stakeholders to reason on city walkability and to compare different points of view in an explicit and articulated way.
Semantic Spatial Representation and Collaborative Mapping in Urban and Regional Planning
Authors: Voghera Angioletta , La Riccia Luigi , Ardissono Liliana
Published: February 2019

This chapter focuses on the theme of the spatial representation of cities and the territory and the collaborative construction of territorial knowledge. The described research concerns the “OnToMap. Mappe di Comunità 3.0” project, focused on the definition of a methodology that implements a semantic representation of territory. That type of representation supports the description of big and open data and of its properties in a unified language. OnToMap enables the sharing of information on the web by providing an integrated perspective on territorial data, as demonstrated in an experimentation with Ph.D. students of the Politecnico di Torino. OnToMap is also part of the H2020 funded project WeGovNow, based on the integration of GIS tools, VGI practices and Web 3.0 applications: an example of citizens' involvement in the urban redevelopment process of Parco Dora in Turin, which aims was make more inclusive (in terms of empowerment) and efficient urban planning policies.
Benefits and Challenges of Collaborative Learning in Online Teacher Education
Authors: Zygouris-Coe Vassiliki I.
Published: February 2019

Demand for online learning is increasing in US colleges and universities. Learning does not occur in a vacuum; students learn independently and collaboratively. But, is there room for collaborative learning in online courses? This chapter presents information on how a teacher educator designed and implemented collaborative learning in a developmental reading online course for preservice and inservice educators in grades P-12. The author presents details on course design issues, instructional practices, benefits, and challenges associated with collaborative learning in this online course, and implications for further development and evaluation of collaborative learning in teacher preparation programs. The author also provides recommendations from lessons learned for promoting collaboration in online teacher education courses.
The Extent of K-12 Online Teacher Development
Authors: Larson Jean S. , Archambault Leanna
Published: February 2019

This chapter, updated for the second edition of this volume, reviews the current research specific to the characteristics and preparation of those involved in K–12 online teaching. While few teacher education programs integrate any aspect of online teaching into their coursework or field experiences, existing programs are discussed. Limited, but notable progress is being made with respect to K–12 online teacher preparation. However, there continues to be gaps in the literature examining the extent to which teachers are being educated, trained, and otherwise prepared to function in online settings. Over the past decade, the need for teacher education programs and current K–12 online schools to work together to prepare teachers has become increasingly clear. Effective online teaching techniques must be defined, empirically proven, and then efficiently implemented by both future and current K–12 online teachers to ensure quality online educational experiences and outcomes for students.
Engaging Online K-12 Students
Authors: Kiekel Jean , Flores Serena , Walters Nicole McZeal
Published: February 2019

Online learning for K-12 is the fastest growing segment of education. Advantages include access to courses for college and career readiness; world languages; science, technology, engineering, and math (STEM), including electives that might otherwise be unavailable to students. However, K-12 students increasingly miss valuable interactions present in face-to-face classes and, as such, engaging students in online courses can be difficult. For this reason, teachers in an online setting must be flexible and creative and find approaches to make the online classroom feel more like a face-to-face classroom. This would include finding ways to decrease the cognitive and emotional distance often associated with not seeing a teacher or fellow students. It also presents the case of school leadership need for exercising caution while implementing school policy to encourage appropriate social media behaviors.
Moving Beyond Trial and Error
Authors: Whiteside Aimee L. , Dikkers Amy Garrett , Baker III Fredrick W.
Published: February 2019

Through 15 years of research on social presence examining the level of connectedness among students and instructors, the authors uncovered a recurring theme: the need for districts to provide better support professional development (PD) in K-12 settings. In this chapter, they address some of the challenges in implementing PD, describe and explain the social presence model (SPM), provide evidence from multiple case studies, and summarize the key findings. The research uncovered that while online and blended teachers often recognized the need for continued support and its role in helping them be more effective educators, they often moved forward without adequate PD. Because the passion and perseverance of these teachers predict long-term success for students, districts need to have a plan in place to help them get the PD needed to maximize their experience and impact student learning most effectively. In closing, the authors offer micro-communities as one robust, socially present, easy-to-implement, and budget-conscious solution that at least partially addresses this growing concern.
Using Video Capture and Annotation Technology to Strengthen Reflective Practices and Feedback in Educator Preparation
Authors: Tschida Christina M. , Gallagher Jennifer L. , Anderson Kimberly L. , Ryan Caitlin L. , Stapleton Joy N. , Jones Karen D.
Published: February 2019

In this chapter, the authors share the history of a video capture and annotation technology (VCAT) implementation and provide summaries of research findings to support its continued use and refinement. They also detail the multiple uses and particular objectives they aimed to meet with the technology across different content areas and even across multiple educator preparation programs, including a collaboration between a teacher education program and principal preparation program that was enabled by the technology.
E-Coaching to Support University-Public School Partnerships
Authors: Bellows Elizabeth , Cheek Aftynne E. , Blanton Morgan
Published: February 2019

Three teacher educators partnered with a local high school to pilot an e-coaching model with secondary social studies pre-service teachers. Findings reveals an e-coaching supervisory model that can nurture relationships between university and public schools to support pre-service teacher (PST) development, can increase a PST's independence and confidence, and can support creation of a third space where power dynamics between university and public schools are disrupted and potentially leveled. Implications for e-coaching as a means of supervising field experiences in rural teacher education are discussed.
Challenges and New Trends in the Design and Implementation of Flipped Learning in K-12 Education
Authors: Jwair Amani Abdullah Bin
Published: February 2019

This chapter explores the quality of learning found when using the flipped learning (FL) approach in K-12 education to promote academic achievement and critical thinking skills, reduce seat time, and improve self-efficacy. The benefits of this approach are controversial, but no clear findings have demonstrated the superiority of learning in a traditional classroom over FL. One perspective claims there are several benefits to using FL in K-12, and many educators and experts assume using this approach in traditional classrooms could show great improvements in student outcomes. The second perspective points out that some educators and specialists have doubts about using flipped methods in traditional classrooms, drawing attention to the challenges K-12 education might face in implementing this approach. The overall findings of this chapter conclude that the benefits of the FL approach supersede the potential challenges. The chapter ends with new trends in the design and implementation of flipped learning in K-12 education.
Framing Historical Thinking in the Digital Age
Authors: Waring Scott M.
Published: February 2019

It is undeniable that students today are fundamentally different than those of previous generations and that many students of this generation do not enjoy history, as it is typically ranked as one of the least favorite subjects in K-12 schools. A large reason for this is the fact that much of the curriculum and instructional approaches are outdated and of little interest to students and do not mirror the approaches and methods employed by historians. As educators increasingly move towards teaching in online environments, it is critical that history educators structure instruction to meet the needs of the student, while making it effective, engaging, and authentic. This chapter focuses on ways that educators, in a mixed-mode or online environment, can attend to the four dimensions of the college, career, and civic life (C3) framework for social studies state standards: helping students in evaluating sources and using evidence, developing questions and planning inquiries, applying disciplinary concepts and tools, and communicating conclusions and taking informed action.
Dialogism in the Digital Age
Authors: Lunsford Lauren , Smith-Whitehouse Bonnie , Lovvorn Jason F.
Published: February 2019

The purpose of this chapter is to provide pre-service and practicing teachers a constructivist lens for viewing how they use technology, specifically online discussion boards, in their classrooms. The chapter explores the way that student-focused and constructivist teachers can utilize technology in ways that remain consistent with maintaining important student relationships, which are so central to paradigm and student success overall. This chapter explores the role of dialogism in a student-centered classroom and provides several specific and practical strategies for ways to use discussion boards in the classroom. Each of these strategies connects to the roots of constructivist beliefs. In particular, this chapter highlights the role that writing can play when using this technology.