bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation on Fluid Flow inside a Continuous Slab Casting Mold Using Particle Image Velocimetry
Authors: Ren Lei , Ren Ying , Zhang Lifeng , Yang Jichun
Published: July 2019

Herein, full region (not divided the mold into several parts) fluid flow in a wide slab mold is studied using a one‐quarter scale water model. The particle image velocimetry (PIV) is used to analyze the turbulent features of the flows. The features include the distribution of instantaneous velocity fields, time‐averaged velocity fields, turbulent fluctuation velocity fields, the turbulent kinetic energy (TKE) and its dissipation rate, rate of strain, and the vorticity. There are several ﬁndings in this study. The fluid flow in the mold is not always symmetrical even the submerged entry nozzle (SEN) is strictly centered, but the time‐averaged flow structure is symmetric flow. The development of turbulence is relatively sufficient in the lower part of the mold, where the flow velocity is large, and the TKE and its dissipation rate are also large. Regions of positive and negative values signify the direction of the flow rotation with mirror images on both sides of the SEN. The regions of high vorticity are close to jets and decrease as it flows further into the mold.
Rotation capacity of composite joints for slim‐floor beams
Authors: Duarte da Costa Job , Obiala Renata , Odenbreit Christoph
Published: July 2019

The analysis of a composite beam‐to‐column structure requires knowledge about, on the one hand, the behaviour of beams and columns and, on the other, the joints between such elements. For beam‐to‐column joints, for example, the lack of appropriate design rules forces structural engineers to model joints as pinned, despite the fact that a certain joint rigidity and bending resistance is available because of the upper reinforced concrete slab.

In this context, a research programme with experimental and numerical investigations was initiated at the University of Luxembourg [1]. This aim of this research was to identify the influence of two major joint components – the reinforced concrete slab and the steelwork connection – on the behaviour of composite joints under a hogging bending moment. Eight experimental tests were performed on beam‐to‐column joints. These tests were used to validate an FE model developed with the ABAQUS software, which allowed the simulation of further joint configurations without the need for additional laboratory tests.

This article presents the results of experimental and numerical analyses. Good agreement was achieved between experimental tests and numerical simulations. The influence of the reinforcement and the steelwork connection on the structural properties of composite joints is derived and a new analytical method is proposed to determine the stiffnesses and rotation capacities of composite joints.
Experimentelle Untersuchungen an Slim‐Floor‐Trägern
Authors: Kuhlmann Ulrike , Lam Dennis , Zandonini Riccardo , Schorr Johannes , Sheehan Therese , Baldassino Nadia
Published: July 2019

In dem europäischen Forschungsprojekt SlimAPP „Slim‐Floor Beams – Preparation of application rules in view of improved safety, functionality and LCA” wurde ein umfassendes Versuchsprogramm zu Slim‐Floor‐Trägern durchgeführt, um ein tieferes Verständnis in das besondere Tragverhalten von Slim‐Floor‐Systemen zu bekommen. Das Versuchsprogramm umfasste Push‐out‐Versuche, Schubträgerversuche mit 4 m Länge, Biegeträgerversuche mit 6 m Länge und Biegeträgerversuche zur Bestimmung des Einflusses von Langzeiteffekten wie Kriechen und Schwinden. Durch die Wahl eines Basisquerschnitts und die Ausführung der verschiedenen Versuchsserien mit den gleichen Parametern und die Verwendung möglichst vergleichbarer Materialeigenschaften wurde eine Übertragbarkeit der Ergebnisse zwischen den Versuchskonfigurationen gewährleistet. Es werden die verschiedenen Versuchsserien, ihre Parameter und Ergebnisse im Einzelnen vorgestellt. Die Ergebnisse erlauben auch Schlussfolgerungen zum Tragverhalten von besonderen Verbunddübeln (CoSFB) und geben Erkenntnisse zum Trag‐ und Verformungsverhalten von Slim‐Floor‐Trägern gerade im Zusammenhang mit der Verdübelung. Ein solches Verständnis zum Tragverhalten von Slim‐Floor‐Trägern ist für eine gezielte effiziente und ökonomische Bemessung wichtig.
Entwicklung der Slim‐Floor‐Bauweise in Europa
Authors: Schäfer Markus , Braun Matthias
Published: July 2019

Flachdecken in Verbundbauweise, auch Slim‐Floor‐ oder Shallow‐Floor‐Bauweise genannt, stellen innovative Deckensysteme für den Geschossbau dar. Dabei handelt es sich um gewalzte oder geschweißte Stahlprofile, die vollständig oder nahezu vollständig in die Decke integriert werden. Diese Bauweise repräsentiert eine der jüngsten Entwicklungen im Stahl‐Verbundbau und hat in den letzten beiden Jahrzehnten immer größere Bedeutung gewonnen. In diesem Beitrag werden die Bauweise und ihre Entwicklung vorgestellt.
Dreischeibenhaus Düsseldorf: der Stahlskelettbau ist eine Ikone der Moderne
Authors: Hauke Bernhard
Published: July 2019

Wer sich ein bisschen für Bauen und Architektur interessiert, kennt das Dreischeibenhaus in Düsseldorf als eine der stählernen Ikonen der Moderne. Aber über die architektonische Bedeutung hinaus hat das Hochhaus auch statisch‐konstruktiv einiges zu bieten. Die aufgehende Konstruktion einschließlich des Kerns ist ein nahezu reines Stahlskelett. Die Rohrstützen waren dem Bauherrn Phoenix‐Rheinrohr geschuldet. Die Deckenkonstruktion mit leichten Verbundträgern und 8 cm dünnen Betonplatten trägt maßgeblich zur herausragenden Leichtigkeit der Gesamtkonstruktion bei. Inzwischen ist das Dreischeibenhaus liebevoll modernisiert. Interessantester Punkt ist hierbei die Fassade, welche das historische Erscheinungsbild bewahrt, aber technisch auf der Höhe der Zeit ist.
Tunneling nanotubes mediate the expression of senescence markers in mesenchymal stem/stromal cell spheroids
Authors: Whitehead Jacklyn , Zhang Jiali , Harvestine Jenna N. , Kothambawala Alefia , Liu Gang-yu , Leach J. Kent
Published: July 2019

The therapeutic potential of mesenchymal stem/stromal cells (MSCs) is limited by acquired senescence following prolonged culture expansion and high-passage numbers. However, the degree of cell senescence is dynamic, and cell-cell communication is critical to promote cell survival. MSC spheroids exhibit improved viability compared with monodispersed cells, and actin-rich tunneling nanotubes (TNTs) may mediate cell survival and other functions through the exchange of cytoplasmic components. Building upon our previous demonstration of TNTs bridging MSCs within these cell aggregates, we hypothesized that TNTs would influence the expression of senescence markers in MSC spheroids. We confirmed the existence of functional TNTs in MSC spheroids formed from low-passage, high-passage, and mixtures of low- and high-passage cells using scanning electron microscopy, confocal microscopy, and flow cytometry. The contribution of TNTs toward the expression of senescence markers was investigated by blocking TNT formation with cytochalasin D (CytoD), an inhibitor of actin polymerization. CytoD-treated spheroids exhibited decreases in cytosol transfer. Compared with spheroids formed solely of high-passage MSCs, the addition of low-passage MSCs reduced p16 expression, a known genetic marker of senescence. We observed a significant increase in p16 expression in high-passage cells when TNT formation was inhibited, establishing the importance of TNTs in MSC spheroids. These data confirm the restorative role of TNTs within MSC spheroids formed with low- and high-passage cells and represent an exciting approach to use higher-passage cells in cell-based therapies.
Resolving intergeneric relationships in the aervoid clade and the backbone of Ptilotus (Amaranthaceae): Evidence from whole plastid genomes and morphology
Authors: Hammer Timothy A. , Zhong Xiao , Colas des Francs‐Small Catherine , Nevill Paul G. , Small Ian D. , Thiele Kevin R.
Published: July 2019

The informally named “aervoid clade” in Amaranthaceae includes ~134 species in five genera: Ptilotus (~120 spp.), Aerva (11 spp.) and the monotypic Nothosaerva, Omegandra, and Kelita. The relationships of the small aervoid genera to the large genus Ptilotus, and relationships between major clades within Ptilotus, are poorly resolved. The aims of this study were to: (1) elucidate relationships between genera and within Ptilotus using a phylogenomic approach; (2) identify morphological characters within each genus to help delimit generic boundaries; and (3) provide an updated taxonomic framework for the aervoids. A well‐supported coding DNA sequence (CDS) phylogeny was constructed for 36 aervoid and 5 outgroup species based on 69 gene sequences derived from assembled whole‐plastid genomes. The CDS tree was used to constrain relationships on a larger phylogeny based on Sanger‐sequenced ITS and matK for 135 taxa, comprising near‐comprehensive sampling within the aervoids. Both datasets were analysed using maximum likelihood and Bayesian inference. Morphological characters were assessed from herbarium specimens. Our study demonstrates that Aerva is polyphyletic; this is resolved by reinstating Ouret and erecting a new genus, Paraerva. Kelita is found to be deeply nested within Ptilotus and is formally synonymised. The well‐resolved phylogeny of Ptilotus presented here will inform future studies in biogeography and character evolution. A taxonomic treatment is provided for all aervoid genera, and new combinations are made.
DNA‐Templated Copper Nanoprobes: Overview, Feature, Application, and Current Development in Detection Technologies
Authors: Chen Chung‐An , Chen Shih‐Chia , Shiddiky Muhammad J. A. , Chen Chien‐Fu , Wu Kevin C.‐W.
Published: July 2019

Metal nanoprobes have recently attracted board research interestinr their application in establishing sensing systems due to their unique optical, electrical, physical, and chemical properties. In comparison to gold and silver nanoprobes, analytical platform based on copper nanoprobes (Cu‐NPs) is still in the early stages of development. In this review, we focus on single‐stranded, and double‐stranded DNA capped Cu‐NPs sensing systems which have been designed for various analytes, including metal ions, anions, small molecules, biomolecules (DNA, RNA, and protein, etc.). In addition, the application of Cu‐NPs in biological labeling or bio‐imaging platforms has also been introduced and summarized.
Progesterone affects sex differentiation and alters transcriptional of genes along circadian rhythm signaling and hypothalamic‐pituitary‐gonadal axes in juvenile Yellow River Carp (Cyprinus carpio var.)
Authors: Xia Xiaohua , Wang Peijin , Wan Ruyan , Chang Zhongjie , Du Qiyan
Published: July 2019

Progesterone (P4) is a biologically active steroid hormone that is involved in the regulation of oocyte growth and maturation, as well as development of the endometrium and implantation in the uterus of humans. It can also stimulate oocyte maturation in female fish, as well as spermatogenesis and sperm motility in male fish. Thus, P4 has been extensively used in human and animal husbandry as a typical progestin. However, P4 remaining in the water environment will pose a potential hazard to aquatic organisms. For example, it can interfere with sex differentiation and reproduction in aquatic vertebrates such as fish. Therefore, we investigated the effects of prolonged progesterone exposure on the expression of genes related to circadian rhythm signaling and the hypothalamic‐pituitary‐gonadal (HPG) axes in Yellow River Carp, which may have a potential impact on their sex differentiation. Our results suggested that P4 exposure altered the expression of genes related to circadian rhythm signaling, which can lead to disorders in the endocrine system and regulate the HPG axes‐related activities. Furthermore, the expression of genes related to the HPG axes was also altered, which might affect gonadal development and the reproductive systems of Yellow River Carp. In addition, these changes may provide a plausible mechanism for the observed shifts in their sex ratio toward females.
Gluon bremsstrahlung in finite media beyond multiple soft scattering approximation
Authors: Mehtar-Tani Yacine
Published: July 2019

Abstract

We revisit the calculation of the medium-induced gluon spectrum in a finite QCD medium and develop a new approach that goes beyond multiple soft scattering approximation. We show by expanding around the harmonic oscillator that the first two orders encompass the two known analytic limits: single hard and multiple soft scattering regimes, valid at high and low frequencies, respectively. Finally, we investigate the sensitivity of our results to the infrared and observe that for large media the spectrum is weakly dependent on the infrared medium scale.
Production of purely gravitational dark matter: the case of fermion and vector boson
Authors: Ema Yohei , Nakayama Kazunori , Tang Yong
Published: July 2019

Abstract

We consider the simplest possibility for a model of particle dark matter in which dark matter has only gravitational interaction with the standard model sector. Even in such a case, it is known that the gravitational particle production in an expanding universe may lead to a correct relic abundance depending on the ination scale and the mass of dark matter particle. We provide a comprehensive and systematic analysis of the gravitational particle production of fermionic and vectorial dark matter, and emphasize that particles which are much heavier than the Hubble parameter but lighter than inaton can also be produced abundantly.
Elliptic non-Abelian Donaldson-Thomas invariants of ℂ3
Authors: Benini Francesco , Bonelli Giulio , Poggi Matteo , Tanzini Alessandro
Published: July 2019

Abstract

We compute the elliptic genus of the D1/D7 brane system in flat space, finding a non-trivial dependence on the number of D7 branes, and provide an F-theory interpretation of the result. We show that the JK-residues contributing to the elliptic genus are in one-to-one correspondence with coloured plane partitions and that the elliptic genus can be written as a chiral correlator of vertex operators on the torus. We also study the quantum mechanical system describing D0/D6 bound states on a circle, which leads to a plethystic exponential formula that can be connected to the M-theory graviton index on a multi-Taub-NUT background. The formula is a conjectural expression for higher-rank equivariant K-theoretic Donaldson-Thomas invariants on ℂ
3.
Work engagement and task performance within a global Dutch ICT-consulting firm: The mediating role of innovative work behaviors
Authors: van Zyl Llewellyn Ellardus , van Oort Amber , Rispens Sonja , Olckers Chantal
Published: July 2019

The information and communication technology (ICT) sector within the Netherlands is a major driver of globalization, the country’s economic growth and innovation. The Dutch ICT sector’s performance is increasingly becoming dependent upon employee driven innovations in order to address the needs of the sectors they service. In other words, the ICT sector within the Netherlands is largely dependent upon the performance and innovative capacity of its employees; both of which are functions of employee engagement. Given the high demand, and low supply of talent within this sector, ICT organizations need to develop innovative ways to enhance the performance capacities of its people. Developing an engaged and highly innovative workforce seems to be an efficient way to activate employees’ performance. As such, the aim of this paper was to investigate the mediating function of employee driven innovative work behaviors in the relationship between work engagement and task performance within the a Dutch ICT consulting firm. A cross-sectional survey-based research design, employing a census-based sampling method, was employed to obtain data from a global ICT consulting firm within the Netherlands (n = 232). The Utrecht Work Engagement Scale, the Innovative Work Behavior Scale and the Task Performance Scale was used to assess the associative subjective experiences of ICT employees. The results showed that work engagement is a significant driver for innovative work behaviors, which in turn affects the task performance of employees. Further, innovative work behaviors are therefore important to translate the engaging energies of employees into performance. This paper discusses the theoretical and practical implications of these findings.
Landscape Structural Violence: A View from New Orleans’s Cemeteries
Authors: Seidemann Ryan M. , Halling Christine L.
Published: July 2019

“Structural violence” is a term used to describe inflicted systematic violence on a disenfranchised group by an established order, usually framed as a government or the social majority. The disenfranchised groups are marginalized and not provided with the same access to resources such as healthcare or food, the effects of which can be observed directly in their death. Bioarchaeologists often can detect the visible effects of this violence on skeletal remains, which provide a visual representation to and reinforcement of social prejudices inflicted in life and death. Discussed here is how the same concept of structural violence can be inflicted on the landscape through damage to or obliteration of cemeteries. We propose a definition of “landscape structural violence” exhibited through cemetery erasure as a reinforcement of preexisting social prejudices in death where the governments or the social majority, intentionally or passively, destroy, remove, or obscure a cemetery without consultation with the descendant community. This definition is applied to several examples of New Orleans cemeteries to determine the functionality of the definition and what activity is and what is not structural violence inflicted on the landscape.
Parental licensing: an Australian perspective
Authors: Ainsworth Frank
Published: July 2019

Parental licensing is the idea that parenting competence should be demonstrated prior to adults achieving full parental rights. It is a long-standing idea that is alive among a host of academic philosophers, political scientists and others interested in children’s rights. The question is – is the notion of parental licensing a good idea or is it an extreme authoritarian response to the social problem of child abuse and neglect? The next question is – if parental licensing was in place, who would decide on parental competence, what are the boundaries of competence and how would competence be measured? And what about those adults who are deemed as incompetent? It is worth considering the proposition that, by endorsing the concept of the “best interests of the child” and passing legislation that gives standing to the removal of a child from parental care, by default this constitutes a system of parental licensing.
Public Venture Capital in a Regional Economy: The Welsh Development Agency, 1976–1994
Authors: GOOBERMAN LEON , BOYNS TREVOR
Published: July 2019

Between 1976 and 1994 the UK Government’s Welsh Development Agency made 2,304 loan and equity investments totaling £117.8 million. The agency aimed to address difficulties faced by firms in obtaining finance, and such intervention was justified by the market failure and spillover hypotheses. This article assesses the agency’s investment activities against both justifications. It finds that while some investments succeeded, the portfolio’s financial performance was poor, and the agency did not address widespread market failure. Evidence of spillover returns existed, but cannot be quantified accurately across the portfolio. The article argues that the agency’s two venture capital objectives, to assemble a profitable portfolio and to grow employment levels through boosting commercial activity, were incompatible within a poorly performing regional economy. Although spillovers can justify public venture capital in such economies, expectations as to financial performance should be realistic in the absence of an ecosystem that facilitates demand for capital.
Extreme events and non-Kolmogorov spectra in turbulent flows behind two side-by-side square cylinders
Authors: Zhou Yi , Nagata Koji , Sakai Yasuhiko , Watanabe Tomoaki
Published: July 2019

Turbulent flows behind two side-by-side square cylinders with three different gap ratios, namely, $L_{d}/T_{0}=4,$ 6 and 8 ($L_{d}$ is the separation distance between two cylinders and $T_{0}$ is the cylinder thickness) are investigated by using direct numerical simulations. Depending on the strength of the gap flow, the three cases can generally be characterized into two regimes, one being the weak gap flow regime and the other being the robust gap flow regime. The wake-interaction length scale can only be applied to characterize the spatial evolution of the dual-wake flow in the robust gap flow regime. And only in this regime can the so-called ‘extreme events’ (i.e. non-Gaussian velocity fluctuations with large flatness) be identified. For the case with $L_{d}/T_{0}=6$, two downstream locations, i.e. $X/T_{0}=6$ and 26, at which the turbulent flows are highly non-Gaussian distributed and approximately Gaussian distributed, respectively, are analysed in detail. A well-defined $-5/3$ energy spectrum can be found in the near-field region (i.e. $X/T_{0}=6$), where the turbulent flow is still developing and highly intermittent and Kolmogorov’s universal equilibrium hypothesis does not hold. We confirm that the approximate $-5/3$ power law in the high-frequency range is closely related to the occurrences of the extreme events. As the downstream distance increases, the velocity fluctuations gradually adopt a Gaussian distribution, corresponding to a decrease in the strength of the extreme events. Consequently, the range of the $-5/3$ power law narrows. In the upstream region (i.e. $X/T_{0}=6$), the second-order structure function exhibits a power-law exponent close to $1$, whereas in the far downstream region (i.e. $X/T_{0}=26$) the expected $2/3$ power-law exponent appears. The larger exponent at $X/T_{0}=6$ is related to the fact that fluid motions in the intermediate range can directly ‘feel’ the large-scale vortex shedding.
Solidification dynamics of an impacted drop
Authors: Thiévenaz V. , Séon T. , Josserand C.
Published: July 2019

This paper is dedicated to the solidification of a water drop impacting a cold solid surface. In the first part, we establish a one-dimensional (1-D) solidification model, derived from the Stefan problem, that aims at predicting the freezing dynamics of a liquid on a cold substrate, taking into account the thermal properties of this substrate. This model is then experimentally validated through a 1-D solidification set-up, using different liquids and substrates. In the second part, we show that during the actual drop spreading, a thin layer of ice develops between the water and the substrate and pins the contact line at its edge when the drop reaches its maximal diameter. The liquid film then remains still on the ice and keeps freezing. This configuration lasts until the contact line eventually unpins and the liquid film retracts on the ice. We measure and interpret this crucial time of freezing during which the main ice layer is built. Finally, we compare our 1-D model prediction to the thickness of this ice pancake and we find a very good agreement. This allows us to provide a general expression for the frozen drop’s main thickness, using the drop’s impact and liquid parameters.
Decaying turbulence in a stratified fluid of high Prandtl number
Authors: Okino Shinya , Hanazaki Hideshi
Published: July 2019

Decaying turbulence in a density-stratified fluid with a Prandtl number up to $Pr=70$ is investigated by direct numerical simulation. In turbulent flow with a Prandtl number larger than unity, it is well known that the passive scalar fluctuations cascade to scales smaller than the Kolmogorov scale, and show the $k^{-1}$ spectrum in the viscous–convective range, down to the Batchelor scale. In decaying stratified turbulence, the same phenomenon is initially observed for the buoyant scalar of high $Pr~(=70)$, until the Ozmidov scale becomes small and the buoyancy becomes effective even at the Kolmogorov scale. After that moment, however, the velocity components near the Kolmogorov scale begin to show strong anisotropy dominated by the vertically sheared horizontal flow, which reduces the vertical scale of density fluctuations. An analysis similar to that of Batchelor (J. Fluid Mech., vol. 5, 1959, pp. 113–133) indeed shows that the vertically sheared horizontal flow reduces the vertical scale of density fluctuations, without changing the horizontal scale.
Dynamics of viscoelastic pipe flow at low Reynolds numbers in the maximum drag reduction limit
Authors: Lopez Jose M. , Choueiri George H. , Hof Björn
Published: July 2019

Polymer additives can substantially reduce the drag of turbulent flows and the upper limit, the so-called state of ‘maximum drag reduction’ (MDR), is to a good approximation independent of the type of polymer and solvent used. Until recently, the consensus was that, in this limit, flows are in a marginal state where only a minimal level of turbulence activity persists. Observations in direct numerical simulations at low Reynolds numbers ($Re$) using minimal sized channels appeared to support this view and reported long ‘hibernation’ periods where turbulence is marginalized. In simulations of pipe flow at $Re$ near transition we find that, indeed, with increasing Weissenberg number ($Wi$), turbulence expresses long periods of hibernation if the domain size is small. However, with increasing pipe length, the temporal hibernation continuously alters to spatio-temporal intermittency and here the flow consists of turbulent puffs surrounded by laminar flow. Moreover, upon an increase in $Wi$, the flow fully relaminarizes, in agreement with recent experiments. At even larger $Wi$, a different instability is encountered causing a drag increase towards MDR. Our findings hence link earlier minimal flow unit simulations with recent experiments and confirm that the addition of polymers initially suppresses Newtonian turbulence and leads to a reverse transition. The MDR state on the other hand results at these low$Re$ from a separate instability and the underlying dynamics corresponds to the recently proposed state of elasto-inertial turbulence.
Swimming mediated by ciliary beating: comparison with a squirmer model
Authors: Ito Hiroaki , Omori Toshihiro , Ishikawa Takuji
Published: July 2019

The squirmer model of Lighthill and Blake has been widely used to analyse swimming ciliates. However, real ciliates are covered by hair-like organelles, called cilia; the differences between the squirmer model and real ciliates remain unclear. Here, we developed a ciliate model incorporating the distinct ciliary apparatus, and analysed motion using a boundary element–slender-body coupling method. This methodology allows us to accurately calculate hydrodynamic interactions between cilia and the cell body under free-swimming conditions. Results showed that an antiplectic metachronal wave was optimal in the swimming speed with various cell-body aspect ratios, which is consistent with former theoretical studies. Exploiting oblique wave propagation, we reproduced a helical trajectory, likeParamecium, although the cell body was spherical. We confirmed that the swimming velocity of model ciliates was well represented by the squirmer model. However, squirmer modelling outside the envelope failed to estimate the energy costs of swimming; over 90 % of energy was dissipated inside the ciliary envelope. The optimal swimming efficiency was given by the antiplectic wave; the value was 6.7 times larger than in-phase beating. Our findings provide a fundamental basis for modelling swimming micro-organisms.
Preservation of the mean residual life order for coherent and mixed systems
Authors: Lindqvist Bo H. , Samaniego Francisco J. , Wang Nana
Published: July 2019

The signature of a coherent system has been studied extensively in the recent literature. Signatures are particularly useful in the comparison of coherent or mixed systems under a variety of stochastic orderings. Also, certain signature-based closure and preservation theorems have been established. For example, it is now well known that certain stochastic orderings are preserved from signatures to system lifetimes when components have independent and identical distributions. This applies to the likelihood ratio order, the hazard rate order, and the stochastic order. The point of departure of the present paper is the question of whether or not a similar preservation result will hold for the mean residual life order. A counterexample is provided which shows that the answer is negative. Classes of distributions for the component lifetimes for which the latter implication holds are then derived. Connections to the theory of order statistics are also considered.
Central limit theorem for mean and variogram estimators in Lévy–based models
Authors: Rønn-Nielsen Anders , Vedel Jensen Eva B.
Published: July 2019

We consider an infinitely divisible random field in ℝd given as an integral of a kernel function with respect to a Lévy basis. Under mild regularity conditions, we derive central limit theorems for the moment estimators of the mean and the variogram of the field.
Cramér type moderate deviations for random fields
Authors: Beknazaryan Aleksandr , Sang Hailin , Xiao Yimin
Published: July 2019

We study the Cramér type moderate deviation for partial sums of random fields by applying the conjugate method. The results are applicable to the partial sums of linear random fields with short or long memory and to nonparametric regression with random field errors.
On the multifractal analysis of the covering number on the Galton–Watson tree
Authors: Attia Najmeddine
Published: July 2019

We consider, for t in the boundary of a Galton–Watson tree $(\partial \textsf{T})$, the covering number $(\textsf{N}_n(t))$ by the generation-n cylinder. For a suitable set I and sequence (sn), we almost surely establish the Hausdorff dimension of the set $\{ t \in \partial {\textsf{T}}:{{\textsf{N}}_n}(t) - nb \ {\sim} \ {s_n}\} $ for b ∈ I.
A spatio-temporal point process model for particle growth
Authors: Hössjer Ola
Published: July 2019

A spatio-temporal model of particle or star growth is defined, whereby new unit masses arrive sequentially in discrete time. These unit masses are referred to as candidate stars, which tend to arrive in mass-dense regions and then either form a new star or are absorbed by some neighbouring star of high mass. We analyse the system as time increases, and derive the asymptotic growth rate of the number of stars as well as the size of a randomly chosen star. We also prove that the size-biased mass distribution converges to a Poisson–Dirichlet distribution. This is achieved by embedding our model into a continuous-time Markov process, so that new stars arrive according to a marked Poisson process, with locations as marks, whereas existing stars grow as independent Yule processes. Our approach can be interpreted as a Hoppe-type urn scheme with a spatial structure. We discuss its relevance for and connection to models of population genetics, particle aggregation, image segmentation, epidemic spread, and random graphs with preferential attachment.
Random affine simplexes
Authors: Götze Friedrich , Gusakova Anna , Zaporozhets Dmitry
Published: July 2019

For a fixed k ∈ {1, …, d}, consider arbitrary random vectors X0, …, Xk ∈ ℝd such that the (k + 1)-tuples (UX0, …, UXk) have the same distribution for any rotation U. Let A be any nonsingular d × d matrix. We show that the k-dimensional volume of the convex hull of affinely transformed Xi satisfies \[|{\rm{conv}}(A{X_{\rm{0}}} \ldots ,A{X_k}){\rm{|}}\mathop {\rm{ = }}\limits^{\rm{D}} (|{P_\xi }\varepsilon |/{\kappa _k})|{\rm{conv}}\left( {{X_0}, \ldots ,{X_k}} \right)\]
, where ɛ:= {x ∈ ℝd : x┬ (A┬ A)−1x ≤ 1} is an ellipsoid, Pξ denotes the orthogonal projection to a uniformly chosen random k-dimensional linear subspace ξ independent of X0, …, Xk, and κk is the volume of the unit k-dimensional ball. As an application, we derive the following integral geometry formula for ellipsoids: ck,d,p ∫Ad,k |ɛ ∩ E|p+d+1 μd,k(dE) = |ɛ|k+1 ∫Gd,k |PLɛ|pνd,k(dL), where $c_{k,d,p} = \big({\kappa_{d}^{k+1}}/{\kappa_k^{d+1}}\big) ({\kappa_{k(d+p)+k}}/{\kappa_{k(d+p)+d}})$
. Here p > −1 and Ad,k and Gd,k are the affine and the linear Grassmannians equipped with their respective Haar measures. The p = 0 case reduces to an affine version of the integral formula of Furstenberg and Tzkoni (1971).
Exact simulation of generalised Vervaat perpetuities
Authors: Dassios Angelos , Qu Yan , Lim Jia Wei
Published: July 2019

We consider a generalised Vervaat perpetuity of the form X = Y1W1 +Y2W1W2 + · · ·, where $W_i \sim {\cal U}^{1/t}$ and (Yi)i≥0 is an independent and identically distributed sequence of random variables independent from (Wi)i≥0. Based on a distributional decomposition technique, we propose a novel method for exactly simulating the generalised Vervaat perpetuity. The general framework relies on the exact simulation of the truncated gamma process, which we develop using a marked renewal representation for its paths. Furthermore, a special case arises when Yi = 1, and X has the generalised Dickman distribution, for which we present an exact simulation algorithm using the marked renewal approach. In particular, this new algorithm is much faster than existing algorithms illustrated in Chi (2012), Cloud and Huber (2017), Devroye and Fawzi (2010), and Fill and Huber (2010), as well as being applicable to the general payments case. Examples and numerical analysis are provided to demonstrate the accuracy and effectiveness of our method.
Absolute regularity of semi-contractive GARCH-type processes
Authors: Doukhan Paul , Neumann Michael H.
Published: July 2019

We prove existence and uniqueness of a stationary distribution and absolute regularity for nonlinear GARCH and INGARCH models of order (p, q). In contrast to previous work we impose, besides a geometric drift condition, only a semi-contractive condition which allows us to include models which would be ruled out by a fully contractive condition. This results in a subgeometric rather than the more usual geometric decay rate of the mixing coefficients. The proofs are heavily based on a coupling of two versions of the processes.
Chinese Adolescents’ Relationships with Mothers, Fathers, and Siblings: Associations With Youth's Internalising and Externalising Problems
Authors: Feng Yi , Whiteman Shawn D. , Xu Siyu , Li Ling , Jin Shenghua , French Doran C.
Published: July 2019

The associations between Chinese adolescents’ family (maternal, paternal, and sibling) relationship qualities and their adjustment were examined among 540 Chinese families over a one-year period. Path analysis revealed that father-offspring positivity was associated with lower levels of internalising problems, whereas mother-offspring conflict predicted youths’ depressive symptoms and loneliness. Controlling for parent-offspring relationships, sibling intimacy inversely predicted youths’ internalising and externalising problems, whereas sibling conflict predicted youths’ loneliness. Multigroup comparisons revealed that youth gender moderated the associations between maternal conflict and youths’ depressive symptoms, as well as sibling intimacy and youths’ loneliness. Overall, results highlight the importance of family systems for Chinese youths’ mental health and the need to study sibling relationships in future studies of Chinese families.
The Party or the Purse? Unequal Representation in the US Senate
Authors: LAX JEFFREY R. , PHILLIPS JUSTIN H. , ZELIZER ADAM
Published: July 2019

Recent work on US policymaking argues that responsiveness to public opinion is distorted by money, in that the preferences of the rich matter much more than those of lower-income Americans. A second distortion—partisan biases in responsiveness—has been less well studied and is often ignored or downplayed in the literature on affluent influence. We are the first to evaluate, in tandem, these two potential distortions in representation. We do so using 49 Senate roll-call votes from 2001 to 2015. We find that affluent influence is overstated and itself contingent on partisanship—party trumps the purse when senators have to take sides. The poor get what they want more often from Democrats. The rich get what they want more often from Republicans, but only if Republican constituents side with the rich. Thus, partisanship induces, shapes, and constrains affluent influence.
Who Leads? Who Follows? Measuring Issue Attention and Agenda Setting by Legislators and the Mass Public Using Social Media Data
Authors: BARBERÁ PABLO , CASAS ANDREU , NAGLER JONATHAN , EGAN PATRICK J. , BONNEAU RICHARD , JOST JOHN T. , TUCKER JOSHUA A.
Published: July 2019

Are legislators responsive to the priorities of the public? Research demonstrates a strong correspondence between the issues about which the public cares and the issues addressed by politicians, but conclusive evidence about who leads whom in setting the political agenda has yet to be uncovered. We answer this question with fine-grained temporal analyses of Twitter messages by legislators and the public during the 113th US Congress. After employing an unsupervised method that classifies tweets sent by legislators and citizens into topics, we use vector autoregression models to explore whose priorities more strongly predict the relationship between citizens and politicians. We find that legislators are more likely to follow, than to lead, discussion of public issues, results that hold even after controlling for the agenda-setting effects of the media. We also find, however, that legislators are more likely to be responsive to their supporters than to the general public.
On the Gibbs–Wilbraham Phenomenon for Sampling and Interpolatory Series
Authors: Hamm Keaton
Published: July 2019

We investigate the Gibbs–Wilbraham phenomenon for generalized sampling series, and related interpolation series arising from cardinal functions. We prove the existence of the overshoot characteristic of the phenomenon for certain cardinal functions, and characterize the existence of an overshoot for sampling series.
New marine reptile fossils from the Oxfordian (Late Jurassic) of Greenland
Authors: Delsett LL , Alsen P
Published: July 2019

Knowledge about marine reptile diversity and disparity during the Late Jurassic is increasing. This contribution describes marine reptile skeletal elements (ichthyosaur and plesiosaur) from Kingofjeld mountain in NE Greenland. The assemblage is early Late Oxfordian (Late Jurassic) in age, and consists ofc. 100 disarticulated skeletal elements. The location is of biogeographic importance as it was at the time situated between the Boreal realm and the Tethys Sea and is promising in terms of future prospecting.
A comparison of the heat stability of fresh milk protein concentrates obtained by microfiltration, ultrafiltration and diafiltration
Authors: Renhe Isis Rodrigues Toledo , Zhao Zhengtao , Corredig Milena
Published: July 2019

The objective of this work was to evaluate the impact of changes during membrane filtration on the heat stability of milk protein concentrates. Dairy protein concentrates have been widely employed in high protein drinks formulations and their stability to heat treatment is critical to ensure quality of the final product. Pasteurized milk was concentrated three-fold by membrane filtration, and the ionic composition was modified by addition of water or permeate from filtration (diafiltration). Diafiltration with water did not affect the apparent diameter of the casein micelles, but had a positive effect on heat coagulation time (HCT), which was significantly longer (50 min), compared to the non diafiltered concentrates (about 30 min). UHT treatments increased the particle size of the casein micelles, as well as the turbidity of retentates. Differences between samples with and without diafiltration were confirmed throughout further analysis of the protein composition of the unsedimentable fraction, highlighting the importance of soluble protein composition on the processing functionality of milk concentrates.
Economic Consequences of State Failure—Legal Capacity, Regulatory Activity, and Market Integration in Poland, 1505–1772
Authors: Malinowski Mikołaj
Published: July 2019

With use of innovative proxies and new annual data, I demonstrate that relatively high legal capacity and regulatory activity of the early-modern Polish parliament, the Seym, was positively associated with deeper domestic commodity market integration. Conversely, the lack of effective law-making, caused by the right of a single delegate to discontinue the Seym’s sessions, fostered market fragmentation. This indicates that early parliamentary regimes required legal capacity to harmonize domestic institutions and reduce the transaction costs. The Polish case suggests a hypothesis that the pre-1800 “Little Divergence” between European parliamentary regimes could be explained by differences in their governments’ capacities.
Haemostasis and analgesia with autologous platelet-rich plasma in tonsillectomy
Authors: Chettri M N , Jayagandhi S K , Konyak Y , Sobita P , Singh M M , Singh A M
Published: July 2019

Objective

A single-centre, single-blinded prospective experimental study was conducted to determine the effectiveness of autologous platelet-rich plasma applied to the tonsillar bed post-operatively in reducing post-operative pain and haemorrhage.

Methods

Platelet-rich plasma, prepared prior to surgery, was applied with calcium gluconate to one randomly chosen tonsillar fossa. Pain and haemorrhage were analysed, using a visual analogue scale and a pre-defined grading scale respectively, four times on the day of surgery at 2-hourly intervals, and thrice on the following day.

Results

The pain score and haemorrhage grade on the test side were lower than on the control side. These findings were statistically significant.

Conclusion

This pilot study, conducted in India, revealed valid positive results for a promising new technology. The manual preparation of platelet-rich plasma could be automated in the future to allow a larger sample size.
Proton acceleration in a laser-induced relativistic electron vortex
Authors: Yi L. Q. , Pusztai I. , Pukhov A. , Shen B. F. , Fülöp T.
Published: July 2019

We show that when a solid plasma foil with a density gradient on the front surface is irradiated by an intense laser pulse at a grazing angle,${\sim}80^{\circ }$, a relativistic electron vortex is excited in the near-critical-density layer after the laser pulse depletion. The vortex structure and dynamics are studied using particle-in-cell simulations. Due to the asymmetry introduced by non-uniform background density, the vortex drifts at a constant velocity, typically$0.2{-}0.3$times the speed of light. The strong magnetic field inside the vortex leads to significant charge separation; in the corresponding electric field initially stationary protons can be captured and accelerated to twice the velocity of the vortex (100–200 MeV). A representative scenario – with laser intensity of$10^{21}~\text{W}~\text{cm}^{-2}$– is discussed: two-dimensional simulations suggest that a quasi-monoenergetic proton beam can be obtained with a mean energy 140 MeV and an energy spread of${\sim}10\,\%$. We derive an analytical estimate for the vortex velocity in terms of laser and plasma parameters, demonstrating that the maximum proton energy can be controlled by the incidence angle of the laser and the plasma density gradient.
Survey of Hepatocystis parasites of fruit bats in the Amurum forest reserve, Nigeria, identifies first host record for Rousettus aegyptiacus
Authors: Atama N. , Manu S. , Ivande S. , Rosskopf S. P. , Matuschewski K. , Schaer J.
Published: July 2019

Parasites of the genus Hepatocystis are close relatives of Plasmodium that frequently infect epauletted fruit bats across West and East Africa. Our understanding of susceptible hosts and prevalence of infection of Hepatocystis remains fragmented. Non-invasive sampling of bat assemblages in representative habitats critically contribute to haemosporidian parasite distribution maps. Here, we report on a survey of Hepatocystis parasite infections in bats undertaken over two consecutive years in a protected area in Nigeria, where prevalence and diversity of bat-infecting haemosporidian parasites have not been studied. Microscopic examination of blood films in combination with PCR detection and sequencing revealed Hepatocystis infections with prevalences of 25% and 42% in the closely related epauletted fruit bats Epomophorus sp. and Micropteropus pusillus. For the first time, mature Hepatocystis gametocytes were identified in one Egyptian fruit bat (Rousettus aegyptiacus). This novel host record was confirmed by parasite and host genotyping and suggests that Hepatocystis parasites have a broader host distribution in African fruit bats than currently known.
Self-harm in women with postpartum mental disorders
Authors: Johannsen Benedicte Marie , Larsen Janne Tidselbak , Laursen Thomas Munk , Ayre Karyn , Howard Louise M. , Meltzer-Brody Samantha , Bech Bodil Hammer , Munk-Olsen Trine
Published: July 2019

Background

Women suffering from first onset postpartum mental disorders (PPMD) have a highly elevated risk of suicide. The current study aimed to: (1) describe the risk of self-harm among women with PPMD and (2) investigate the extent to which self-harm is associated with later suicide.

Methods

We conducted a register-based cohort study linking national Danish registers. This identified women with any recorded first inpatient or outpatient contact to a psychiatric facility within 90 days after giving birth to their first child. The main outcome of interest was defined as the first hospital-registered episode of self-harm. Our cohort consisted of 1 202 292 women representing 24 053 543 person-years at risk.

Results

Among 1554 women with severe first onset PPMD, 64 had a first-ever hospital record of self-harm. Women with PPMD had a hazard ratio (HR) for self-harm of 6.2 (95% CI 4.9–8.0), compared to mothers without mental disorders; but self-harm risk was lower in PPMD women compared to mothers with non-PPMD [HR: 10.1, (95% CI 9.6–10.5)] and childless women with mental disorders [HR: 9.3 (95% CI 8.9–9.7)]. Women with PPMD and records of self-harm had a significantly greater risk for later suicide compared with all other groups of women in the cohort.

Conclusions

Women with PPMD had a high risk of self-harm, although lower than risks observed in other psychiatric patients. However, PPMD women who had self-harmed constituted a vulnerable group at significantly increased risk of later suicide.
Detection and Tracking of Moving Obstacles (DATMO): A Review
Authors: Llamazares Ángel , Molinos Eduardo J. , Ocaña Manuel
Published: July 2019

Working with mobile robots, prior to execute the local planning stage, they must know the environment where they are moving. For that reason the perception and mapping stages must be performed previously. This paper presents a survey in the state of the art in detection and tracking of moving obstacles (DATMO). The aim of what follows is to provide an overview of the most remarkable methods at each field specially in indoor environments where dynamic obstacles can be potentially more dangerous and unpredictable. We are going to show related DATMO methods organized in three approaches: model-free, model-based and grid-based. In addition, a comparison between them and conclusions will be presented.