bluuebunny/crossref_metadata_2025_split huggingface dataset:
The organizational design of entrepreneurial ventures
Authors: Burton M. Diane , Colombo Massimo G. , Rossi‐Lamastra Cristina , Wasserman Noam 
Published: July 2019

AbstractResearch SummaryStudying the organizational design of entrepreneurial ventures involves investigating how entrepreneurs design the (formal) structure of their ventures as well as the roles, rules, and procedures that those who are active within these ventures must obey. The topic lies at the intersection of entrepreneurship with multiple fields, including organization science, organizational economics, and strategic management. However, to date, it has attracted limited attention. This special issue includes six articles that develop novel theory and provide new empirical evidence on the antecedents and consequences of the organizational design of entrepreneurial ventures. Collectively they offer fresh perspectives on this neglected topic and open avenues for future work. In this article, we briefly describe the state of the field, introduce the articles, and suggest opportunities for further research.Managerial SummaryThere are countless how‐to guides for entrepreneurs describing start‐up legal structures, incubation and acceleration opportunities, and financing options. Conversely, there is relatively little guidance for how entrepreneurs should design their organizational structure, decision systems, and managerial practices. This special issue contains six articles addressing the organizational design of entrepreneurial ventures from multiple perspectives and with diverse methods. This introduction describes the state of the field prior to the special issue, introduces the special issue articles and identifies topics that still need further investigation. We distill the current state of knowledge and offer a roadmap for future scholarship.
Wearable Electronics Based on 2D Materials for Human Physiological Information Detection
Authors: Pang Yu , Yang Zhen , Yang Yi , Ren Tian‐Ling 
Published: July 2019

AbstractRecently, advancement in materials production, device fabrication, and flexible circuit has led to the huge prosperity of wearable electronics for human healthcare monitoring and medical diagnosis. Particularly, with the emergence of 2D materials many merits including light weight, high stretchability, excellent biocompatibility, and high performance are used for those potential applications. Thus, it is urgent to review the wearable electronics based on 2D materials for the detection of various human signals. In this work, the typical graphene‐based materials, transition‐metal dichalcogenides, and transition metal carbides or carbonitrides used for the wearable electronics are discussed. To well understand the human physiological information, it is divided into two dominated categories, namely, the human physical and the human chemical signals. The monitoring of body temperature, electrograms, subtle signals, and limb motions is described for the physical signals while the detection of body fluid including sweat, breathing gas, and saliva is reviewed for the chemical signals. Recent progress and development toward those specific utilizations are highlighted in the Review with the representative examples. The future outlook of wearable healthcare techniques is briefly discussed for their commercialization.
Analysing encryption mechanisms and functional safety in a ROS‐based architecture
Authors: Larrucea Xabier , González‐Nalda Pablo , Etxeberria‐Agiriano Ismael , Otero Mari Carmen 
Published: July 2019

AbstractRobot Operating System (ROS) is a middleware for connecting different components of robots. However, its use is becoming more popular in other domains such as in the automotive sector where initial prototypes have been customized and deployed in cars for demonstrating different functional purposes. Nevertheless, ROS has not been yet tested enough to be used in secure and safety environments. For example, in order to strengthen our ROS architecture, we have encrypted the messages within it. Therefore, this paper analyses the impact of Advanced Encryption Standard (AES) encryption mechanism and the functional safety of our prototype. In this sense, we are considering encrypting messages and we assess the timing constraints, as suggested by the ISO 26262, required for assuring a secure communication between components.
Experimental study and design of a new hybrid RC frame system with stiffened masonry wall subjected to cyclic loading
Authors: Ma Xiaofei , Ma Jianxun , Bai Yongtao 
Published: July 2019

SummaryThis paper experimentally investigates the hysteresis behavior of a hybrid reinforced concrete (RC) frame system with stiffened masonry wall to enhance the seismic performance of existing RC buildings subjected to cyclic loading. The influences of the depth of the columns section, the length of masonry walls, and the grouting ratio of reinforced masonry were evaluated by designing a series of orthogonal quasi‐static tests on a half‐scale specimen. Test results indicated that the grouting ratio played the most significant role on the maximum strength, energy dissipation capacity, and the relative stiffness degradation rate of the hybrid structural system, whereas the length of masonry walls tends to dominate the deformation capacity. A trilinear analytical model and design recommendations are proposed to estimate the cyclic behavior based on force‐displacement hysteresis law that takes account of the effects of the post‐peak strength and unloading stiffness degradation.
Island biogeography of the Macaronesian Gesnouinia and Mediterranean Soleirolia (Parietarieae, Urticaceae) with implications for the evolution of insular woodiness
Authors: Schüßler Christina , Bräuchler Christian , Reyes‐Betancort Jorge A. , Koch Marcus A. , Thiv Mike 
Published: July 2019

Urticaceae tribe Parietarieae serves as an excellent example to study hypotheses on Macaronesian‐​Mediterranean island biogeography. Parietarieae is distributed in both of these floristically closely related regions and contains two island endemic genera. Gesnouinia is endemic to Macaronesia and was considered a Tertiary relict from a European paleotropical vegetation. This, however, may contradict the general idea of insular woodiness also proposed for this genus. For the origin of the western Mediterranean island endemic Soleirolia, a vicariance scenario, i.e., the split of the Hercynian massif in southern Europe has been suggested. To evaluate these hypotheses and to provide a time frame for island and inter‐island colonization, we applied molecular phylogenetics and dating based on two plastid and one nuclear DNA marker. Additionally, we performed ancestral area reconstruction, analyzed the anatomy of the stem and reconstructed the ancestral character states of woodiness. Our results indicate that Gesnouinia colonized Macaronesia during the Miocene via long‐distance dispersal and may, therefore, be a Tertiary laurel forest relict. Diversification between the laurel forest species Gesnouinia arborea and the rupicolous and more xeric G. filamentosa occurred within Macaronesia during the Pleistocene, possibly due to climate fluctuations. Therefore, G. arborea is not a relict from the Tertiary. Stem anatomy suggests that although woodiness in Gesnouinia likely is derived, it may have evolved prior to island colonization. Soleirolia originated in the Mediterranean during the Miocene. This rules out vicariance from the split of the Hercynian massif in southern Europe during the Oligocene. The divergence of Soleirolia from Majorca, Corsica, Sardinia and the Italian mainland dates to the Pleistocene. This indicates long‐distance dispersal as predominant colonization mode, not ruling out that migration between these areas was possibly facilitated by land bridges during the Pleistocene glaciation cycles.
A Kerr‐type elastic foundation model for the buckling analysis of a beam bonded on an elastic layer
Authors: Zhang L. , Wu G. T. , Wu J. 
Published: July 2019

AbstractA Kerr‐type elastic foundation model is proposed to study the buckling of a beam bonded on the top of a linear elastic layer. The layer's lower‐surface is either bonded or sliding on a rigid substrate. The present Kerr‐type model provides a linear differential relation between the pressure and the normal deflection of the layer's upper‐surface, and reduces to the existing foundation models when high‐order differential relations are neglected. The critical buckling force is then obtained for both an infinitely long beam and a simply‐supported beam of finite length, based on a simple formula which is valid for both a compressible and an incompressible layer. Reasonable agreement with the existing numerical results and our finite element results shows that the present model has the capability to capture the support effect of the elastic layer, and can be used to study the buckling or the bending of a beam bonded on an elastic layer.
Tracing the delinquency acquisition sequence from older siblings, to friends, to self: A mediation analysis
Authors: Walters Glenn D. 
Published: July 2019

ABSTRACTIntroductionThis study tested the hypothesis that sibling and peer delinquency are connected and that this connection is relevant to future criminal offending.MethodsDrawing on research showing that both sibling and peer delinquency predict future participant offending, a causal mediation analysis was performed on 411 boys from the Cambridge Study in Delinquent Development. In this study, older sibling delinquency served as the independent variable, school problem behavior and friend delinquency served as mediator variables, and participant's reports of their own offending served as the dependent variable.ResultsThe indirect effect running from older sibling delinquency at age 10–11, to school problem behavior at age 12–13, to friend delinquency at age 14–15, to participant delinquency at age 16–17 proved significant. The effect remained significant when the number of officially recorded criminal convictions between the ages of 16 and 19 replaced self‐reported delinquency as the dependent variable. By contrast, the direct effect from sibling delinquency at age 10–11 to participant delinquency at age 16–17 and several shorter paths (older sibling delinquency → school problem behavior → participant delinquency; older sibling delinquency → friend delinquency → participant delinquency) were non‐significant.ConclusionsThese results imply that older sibling delinquency may lead to future delinquency and crime by encouraging early school problems, which, in turn, may precipitate future offending by encouraging the child to select and associate with a delinquent peer group.
Evolution of similarity lengths in anisotropic magnetohydrodynamic turbulence
Authors: Bandyopadhyay Riddhi , Matthaeus William H. , Oughton Sean , Wan Minping 
Published: July 2019

In an earlier paper (Wan et al., J. Fluid Mech., vol. 697, 2012, pp. 296–315), the authors showed that a similarity solution for anisotropic incompressible three-dimensional magnetohydrodynamic (MHD) turbulence, in the presence of a uniform mean magnetic field $\boldsymbol{B}_{0}$, exists if the ratio of parallel to perpendicular (with respect to $\boldsymbol{B}_{0}$) similarity length scales remains constant in time. This conjecture appears to be a rather stringent constraint on the dynamics of decay of the energy-containing eddies in MHD turbulence. However, we show here, using direct numerical simulations, that this hypothesis is indeed satisfied in incompressible MHD turbulence. After an initial transient period, the ratio of parallel to perpendicular length scales fluctuates around a steady value during the decay of the eddies. We show further that a Taylor–Kármán-like similarity decay holds for MHD turbulence in the presence of a mean magnetic field. The effect of different parameters, including Reynolds number, mean field strength, and cross-helicity, on the nature of similarity decay is discussed.
Insights into the periodic gust response of airfoils
Authors: Wei Nathaniel J. , Kissing Johannes , Wester Tom T. B. , Wegt Sebastian , Schiffmann Klaus , Jakirlic Suad , Hölling Michael , Peinke Joachim , Tropea Cameron 
Published: July 2019

The unsteady lift response of an airfoil in a sinusoidal gust has in the past been modelled by two different transfer functions: the first-order Sears function and the second-order Atassi function. Previous studies have shown that the Sears function holds in experiments, but recently Cordes et al. (J. Fluid Mech., vol. 811, 2017) reported experimental data that corresponded to the Atassi function rather than the Sears function. In order to clarify the observed discrepancy, the specific differences between these models are isolated analytically. To this end, data and analysis are confined to unloaded airfoils. These differences are related to physical gust parameters, and gusts with these parameters are then produced in wind-tunnel experiments using an active-grid gust generator. Measurements of the unsteady gust loads on an airfoil in the wind tunnel at Reynolds numbers ($Re_{c}$) of $2.0\times 10^{5}$ and $2.6\times 10^{5}$ and reduced frequencies between $0.09$ and $0.42$ confirm that the Sears and Atassi functions differ only in convention: the additional gust component of the Atassi problem can be scaled so that the Atassi function collapses onto the Sears function. These experiments, complemented by numerical simulations of the set-up, validate both models across a range of gust parameters. Finally, the influence of boundary-layer turbulence and the turbulent wake of the gust generator on experimental convergence with model predictions is investigated. These results serve to clarify the conditions under which the Sears and Atassi functions can be applied, and demonstrate that the Sears function can effectively model unsteady forces even when significant fluctuations in the streamwise velocity are present.
Bragg peak characteristics of proton beams within therapeutic energy range and the comparison of stopping power using the GATE Monte Carlo simulation and the NIST data
Authors: Zarifi Shiva , Taleshi Ahangari Hadi , Jia Sayyed Bijan , Tajik-Mansoury Mohammad Ali , Najafzadeh Milad , Firouzjaei Milad Peer 
Published: July 2019

AbstractPurpose:To examine detail depth dose characteristics of ideal proton beams using the GATE Monte Carlo technique.Methods:In this study, in order to improve simulation efficiency, we used pencil beam geometry instead of parallel broad-field geometry. Depth dose distributions for beam energies from 5 to 250 MeV in a water phantom were obtained. This study used parameters namedRpeak,R90,R80,R73,R50, full width at half maximum (FWHM), width of 80–20% distal fall-off (W(80–20)) and peak-to-entrance ratio to represent Bragg peak characteristics. The obtained energy–range relationships were fitted into third-order polynomial formulae. The present study also used the GATE Monte Carlo code to calculate the stopping power of proton pencil beams in a water cubic phantom and compared results with the National Institute of Standards and Technology (NIST) standard reference database.Results:The study results revealed deeper penetration, broader FWHM and distal fall-off and decreased peak-to-entrance dose ratio with increasing beam energy. Study results for monoenergetic proton beams showed thatR73can be a good indicator to characterise a range of incident beams. These also suggest FWHM is more sensitive thanW(80–20)distal fall-off in finding initial energy spread. Furthermore, the difference between the obtained stopping power from simulation and NIST data almost in all energies was lower than 1%.Conclusion:Detail depth dose characteristics for monoenergetic proton beams within therapeutic energy ranges were reported. These results can serve as a good reference for clinical practitioners in their daily practice.
What Controls Sill Formation: An Overview From Analogue Models
Authors: Sili G. , Urbani S. , Acocella V. 
Published: July 2019

AbstractUnderstanding the mechanisms of shallow magma storage (less than ~10‐km depth) is crucial to defining volcanic plumbing systems and their effect on volcano unrest. Sills are common structures to emplace shallow magma. Many factors may control sill emplacement, but their relative importance has not been evaluated so far. To define a hierarchy among a selection of the proposed factors, we performed analogue models by injecting water at constant flux (magma analogue) within gelatin (crust analogue), investigating the effects of: interface strength and rigidity contrast between layers, density layering, ratio of layer thickness, compressive stresses, magma flow rate, and buoyancy pressure. Our results show that a strong rigidity contrast (i.e., a stiff layer overlying a weak one) and a higher buoyancy pressure are necessary and sufficient conditions for sill emplacement. Low rigidity contrasts require other contributions (weak interface and compressive stress) to develop sills; however, without rigidity contrast sill formation is always inhibited. These experiments suggest that sill emplacement is primarily controlled by rigidity contrasts and magma buoyancy pressure; the second‐order parameters are lateral compression and weak interfaces; the third‐order parameters are the ratio of layer thicknesses, magma flow rate, and density layering. These results are in agreement with field observations in Iceland, Tenerife, Utah, and La Réunion, supporting our proposed hierarchy.
Burrowing Invasive Species: An Unquantified Erosion Risk at the Aquatic‐Terrestrial Interface
Authors: Harvey Gemma L. , Henshaw Alexander J. , Brasington James , England Judy 
Published: July 2019

AbstractInvasive nonnative species acting as “ecosystem engineers” or “geomorphic agents” can represent a major landscape disturbance. Quantification of their biogeomorphic impacts remains a key knowledge gap, and aquatic‐terrestrial transition zones may be particularly exposed to impacts. We demonstrate how burrowing invasive species represent a potentially significant but unquantified erosion risk at aquatic margins. We reveal a lack of quantitative research on geophysical impacts, despite increasing concerns over threats to waterways and flood defense infrastructure. We explore example animals of global interest, comprising crustaceans, fish, reptiles, and mammals and reveal the global nature of the issue: over 100 countries, states, or territories where at least one example species is established, and over 20 with 3‐6 species present. We present a conceptual model for the impacts of burrows on stability and erosion at aquatic margins using established models of geotechnical, hydrological, and hydraulic drivers. Burrows are hypothesized to (i) alter failure plane position, decrease failure plane length, and increase failure plane angle (thereby decreasing bank shear strength); (ii) modify the spatial distribution of porewater pressure, thereby increasing subsurface flow (seepage), reducing cohesion, and increasing the likelihood of slip failures at the bank face; (iii) increase turbulence and sediment entrainment at burrow entrances; and (iv) alter flow resistance at the bank face. Most effects are expected to increase bank instability/erosion with the exception of (iv) which has the potential to offer protection from fluvial action. We call for further research in these areas to quantify impacts for different environments and different invasive species.
Three‐Dimensional Modeling of Callisto's Surface Sputtered Exosphere Environment
Authors: Vorburger Audrey , Pfleger Martin , Lindkvist Jesper , Holmström Mats , Lammer Helmut , Lichtenegger Herbert I. M. , Galli André , Rubin Martin , Wurz Peter 
Published: July 2019

AbstractWe study the release of various elements from Callisto's surface into its exosphere by plasma sputtering. The cold Jovian plasma is simulated with a 3‐D plasma‐planetary interaction hybrid model, which produces 2‐D surface precipitation maps for magnetospheric H+, O+, O++, and S++. For the hot Jovian plasma, we assume isotropic precipitation onto the complete spherical surface. Two scenarios are investigated: one where no ionospheric shielding takes place and accordingly full plasma penetration is implemented (no‐ionosphere scenario) and one where an ionosphere lets virtually none of the cold plasma but all of the hot plasma reach Callisto's surface (ionosphere scenario). In the 3‐D exosphere model, neutral particles are sputtered from the surface and followed on their individual trajectories. The 3‐D density profiles show that whereas in the no‐ionosphere scenario the ram direction is favored, the ionosphere scenario produces almost uniform density profiles. In addition, the density profiles in the ionosphere scenario are reduced by a factor of ∼2.5 with respect to the no‐ionosphere scenario. We find that the Neutral Gas and Ion Mass Spectrometer, which is part of the Particle Environment Package on board the JUpiter ICy moons Explorer mission, will be able to detect the different sputter populations from Callisto's icy surface and the major sputter populations from Callisto's nonicy surface. The chemical composition of Callisto's exosphere can be directly linked to the chemical composition of its surface and will offer us information not only on Callisto's formation scenario but also on the building blocks of the Jupiter system.
Sea Ice Detection Using GNSS‐R Data From TechDemoSat‐1
Authors: Cartwright Jessica , Banks Christopher J. , Srokosz Meric 
Published: July 2019

AbstractA new method for the detection of sea ice using GNSS‐R (Global Navigation Satellite Systems Reflectometry) is presented and applied to 33 months of data from the U.K. TechDemoSat‐1 mission. This method of sea ice detection shows the potential for a future GNSS‐R polar mission, attaining an agreement of over 98% and 96% in the Antarctic and Arctic, respectively, when compared to the European Space Agency's Climate Change Initiative sea ice concentration product. The algorithm uses a combination of two parameters derived from the delay‐Doppler Maps to quantify the spread of power in delay and Doppler. Application of thresholds then allows sea ice to be distinguished from open water. Differences between the TechDemoSat‐1 sea ice detection and comparison data sets are explored. The results provide information on the seasonal and multiyear changes in sea ice distribution of the Arctic and Antarctic. Future potential and applications of this technique are discussed.
Abrupt Stratospheric Vortex Weakening Associated With North Atlantic Anticyclonic Wave Breaking
Authors: Lee S. H. , Charlton‐Perez A. J. , Furtado J. C. , Woolnough S. J. 
Published: July 2019

AbstractThe sudden stratospheric warming (SSW) of 12 February 2018 was not forecast by any extended‐range model beyond 12 days. From early February, all forecast models that comprise the subseasonal‐to‐seasonal (S2S) database abruptly transitioned from indicating a strong stratospheric polar vortex (SPV) to a high likelihood of a major SSW. We demonstrate that this forecast evolution was associated with the track and intensity of a cyclone in the northeast Atlantic, with an associated anticyclonic Rossby wave break, which was not well forecast. The wave break played a pivotal role in building the Ural high, which existing literature has shown was a precursor of the 2018 SSW. The track of the cyclone built an anomalously strong sea level pressure dipole between Scandinavia and Greenland (termed the S‐G dipole), which we use as a diagnostic of the wave break. Forecasts that did not capture the magnitude of this event had the largest errors in the SPV strength and did not show enhanced vertical wave activity. A composite of 49 similarly strong wintertime (November–March) S‐G dipoles in reanalysis shows associated anticyclonic wave breaking leading to significantly enhanced vertical wave activity and a weakened SPV in the following days, which occurred in 35% of the 15‐day periods preceding observed major SSWs. Our results indicate a particular transient trigger for weakening the SPV, complementing existing results on the importance of tropospheric blocking for disruptions to the Northern Hemisphere extratropical stratospheric circulation.