bluuebunny/crossref_metadata_2025_split huggingface dataset:
Digital technologies, employment, and skills
Authors: Reljic Jelena , Evangelista Rinaldo , Pianta Mario 
Published: September 2021

AbstractThis article investigates the relationship between the diffusion of digital technologies, employment, and skills. The empirical analysis is carried out on industry-level data of six major European economies (Germany, France, Spain, Italy, the Netherlands, and the UK) over the 2009–2014 period. We analyze two dimensions of digitalization: industries’ consumption of intermediate inputs from digitally intensive sectors and investment in Information and Communication Technology (ICT) tangible and intangible assets, considering also patterns of demand, education, technological change, and offshoring. The results show that job creation in industries is positively associated with an increasing share of digital goods and services in total intermediate inputs and is negatively linked with processes of ICT capital deepening. We then explore how these two different patterns of digitalization are related to the evolution of four occupational groups—managers, clerks, craft, and Manual workers, defined on the basis of International Standard Classification of Occupations classes—finding a positive link between ICT consumption and managerial jobs, and negative ones between digital variables and mid-skill occupations.
External financing of innovative small and medium enterprises (SMEs): unpacking bank credit with respect to innovation typologies and combinations
Authors: Gregori Tullio , Montresor Sandro , Rossi Stefania Ps 
Published: September 2021

Abstract
We investigate the extent to which small and medium enterprises’ (SMEs) external financing varies with the innovation profiles they reveal in terms of introduced and combined innovation typologies. Using Survey on the Access to Finance of Enterprises data, we address this research issue with respect to 11 European countries over the 2014–2019 period and overcome the context specificity of previous analyses. Results suggest that the innovative profile of SMEs is responsible for several nuances in both their demand for and supply of bank loans. Being an innovator increases SMEs’ credit requests, but this demand increases also and above all with their involvement in specific innovation typologies and combinations. Having an innovative profile of nearly any type does not lead SMEs to refrain from demanding bank loans because of a fear of rejection, but a wide involvement in specific innovation types reduces the chance that their internal funds make them refrain from asking for credit. Innovative SMEs are significantly more likely to be credit-constrained than non-innovative ones, but the probability of not receiving bank loans increases only for firms that combine specific innovation typologies. An innovation status of SMEs makes banks more selective in their decision to completely fulfill a credit request, but the probability of this decision decreases only with respect to a few, multi-innovation profiles. The extent to which SMEs innovate in different domains, rather than the simple innovation intensity, appears to be a crucial dimension to consider in future research and in devising policies to attenuate financial constraints to innovation.
Phenological diversity of a prey species supports life-stage specific foraging opportunity for a mobile consumer
Authors: Chamberlin Joshua , Petrou Eleni , Duguid Will , Barsh Russel , Juanes Francis , Qualley Jessica , Hauser Lorenz 
Published: September 2021

AbstractDynamic prey resources influence foraging opportunities for consumers. In coastal food webs, forage fish abundance and seasonal reproduction mediate foraging opportunities for mobile consumers. Recent declines in Chinook salmon productivity have prompted efforts to determine whether poor marine survival is caused by limited feeding opportunities. To establish the importance of phenological diversity in Pacific herring for Chinook salmon, we used genetic stock identification to assign individual herring collected from the guts of juvenile and adult Chinook salmon to populations with distinct spawning phenologies. The majority of herring in the guts of adult Chinook salmon across seasons and geographic areas were dominated by the March–April herring spawn group, but juvenile Chinook salmon diets varied seasonally, with a higher proportion of January–February spawners in summer than in spring. Our results suggest that (1) population diversity of Pacific herring is used by juvenile Chinook salmon and thus contributes to their growth, and (2) stock-specific distribution of Pacific herring extends well beyond documented spawning grounds. Herring population diversity may therefore support foraging opportunities for Chinook salmon during a critical period and highlights the need for future research to quantify seasonal distribution and abundance of phenologically distinct groups of Pacific herring within Salish Sea.
Reconciling conflicting survey indices of abundance prior to stock assessment
Authors: Peterson Cassidy D , Courtney Dean L , Cortés Enric , Latour Robert J 
Published: September 2021

Abstract
Indices of relative abundance are one of the most important inputs into a stock assessment model. For many species, we must rely on several indices that routinely conflict with each other and which may result in biased and uncertain outputs. Here, we explored whether reconciled trends obtained from dynamic factor analysis (DFA) applied to conflicting indices can be used as a trend of relative abundance input into a stock assessment model. We simulated an age-structured population of two coastal shark species in the southeast United States to generate multiple disagreeing indices, reconciled the indices using DFA, and then inserted both the multiple conflicting survey indices and the simplified DFA-predicted trend into respective stock assessment models. We compared the results of each stock assessment model to simulated values to evaluate the relative performance of each approach. We found that the DFA-based assessment generally performed similarly to the conflicting index-based assessment and may be a useful assessment tool in situations where conflicting indices with different selectivities, catchabilities, variances, and missing data are present. DFA assessment results were more consistent across simulation scenarios and outperformed many conflicting index assessments when surveys underwent shifts in catchability and the underlying stock abundance exhibited contrast.
Identifying juvenile and sub-adult movements to inform recovery strategies for a high value fishery—European bass (Dicentrarchus labrax)
Authors: Stamp Thomas , Clarke David , Plenty Shaun , Robbins Tim , Stewart James E , West Elizabeth , Sheehan Emma 
Published: September 2021

Abstract
The European bass (Dicentrarchus labrax) support high value commercial and recreational fisheries, however the Spawning Stock Biomass (SSB) of the northern Atlantic stock (ICES divisions 4.b–c, 7.a, and 7.d–h) has rapidly declined to an unsustainable level. The decline in SSB has been attributed to high fishing pressure combined with poor recruitment. By tracking juvenile fish their spatial ecology can be identified, and appropriate fisheries management policies designed to boost recruitment can be implemented. Using acoustic telemetry 146 sub-adult European bass (25.2–60 cm fork length) were tracked for up to 370 d across three sites in the southwest of the UK. Tagged fish were detected 2 724 548 times (Range: 166–106 393 detections per fish). Linear modelling estimated tagged fish were resident within 2.4–20.1 km of the site where they were first caught for 42.9–75.5% of the year. Some fish were however resident throughout summer and winter. Individual fish were also tracked moving up to 317 km to other coastal sites, 81% of which returned to their original capture site. Fisheries management should account for the high site fidelity displayed by juveniles and sub-adults of this species and coastal nursery sites should be considered essential habitat.
Mesopelagic flesh shear viscosity estimation from in situ broadband backscattering measurements by a viscous–elastic model inversion
Authors: Khodabandeloo Babak , Agersted Mette Dalgaard , Klevjer Thor A , Pedersen Geir , Melle Webjørn 
Published: September 2021

Abstract
In fisheries acoustics, target strength (TS) is a key parameter in converting acoustic measurements to biological information such as biomass. Modelling is a versatile tool to estimate TS of marine organisms. For swimbladdered fish, flesh shear viscosity is one of the required parameters to correctly calculate TS around the resonance frequency, where the target scatters most strongly. Resonance of mesopelagic swimbladdered fish can occur over a range of frequencies and can be within commonly used frequencies (e.g. 18, 38, or 70 kHz). Since there is little information on flesh shear viscosity of fish, especially for mesopelagic species, their resonance can bias the biological information extracted from acoustic measurements. Here, first, the applicability of using a spherical model to estimate resonant backscattering of a generic swimbladder is investigated. Subsequently, a viscous–elastic spherical gas backscattering model is used to estimate the flesh shear viscosity of swimbladdered mesopelagic fish (most likely Cyclothone spp., Family: Gonostomatidae) from in situ broadband backscattering measurements. Finally, the effects of flesh shear viscosity on the TS of swimbladdered mesopelagic fish at 18, 38 (a widely used channel to study mesopelagic layers), and 70 kHz are examined.
Heterogeneity around CO2 vents obscures the effects of ocean acidification on shallow reef communities
Authors: Blain Caitlin O , Kulins Sara , Radford Craig A , Sewell Mary A , Shears Nick T 
Published: September 2021

AbstractStudies that use CO2 vents as natural laboratories to investigate the impacts of ocean acidification (OA) typically employ control-impact designs or local-scale gradients in pH or pCO2, where impacted sites are compared to reference sites. While these strategies can accurately represent well-defined and stable vent systems in relatively homogenous environments, it may not adequately encompass the natural variability of heterogeneous coastal environments where many CO2 vents exist. Here, we assess the influence of spatial heterogeneity on the perceived impacts of OA at a vent system well established in the OA literature. Specifically, we use a multi-scale approach to investigate and map the spatial variability in seawater pH and benthic communities surrounding vents at Whakaari-White Island, New Zealand to better understand the scale and complexity of ecological impacts of an acidified environment. We found a network of vents embedded in complex topography throughout the study area, and spatially variable pH and pCO2 levels. The distribution of habitats (i.e. macroalgal forests and turfing algae) was most strongly related to substratum type and sea urchin densities, rather than pH. Epifaunal communities within turfing algae differed with sampling distance from vents, but this pattern was driven by higher abundances of a number of taxa immediately adjacent to vents, where pH and temperature gradients are steep and white bacterial mats are prevalent. Our results contrast with previous studies at White Island that have used a control-impact design and suggested significant impacts of elevated CO2 on benthic communities. Instead, we demonstrate a highly heterogeneous reef where it is difficult to separate effects of reduced pH from spatial variation in reef communities. We urge that future research carefully considers and quantifies the biological and physical complexity of venting environments, and suggest that in dynamic systems, such as White Island, the use of control-impact designs can oversimplify and potentially overestimate the future impacts of OA.
A ruptured giant mediastinal mature teratoma mimicking an encapsulated empyema
Authors: Zhang Junjie , Zhu Xiaobo , Jiang Minyan , Lv Yajun 
Published: September 2021

Abstract
A female patient with a right-sided encapsulated pleural effusion was misdiagnosed preoperatively as having an encapsulated empyema. However, a giant mass in the anterior mediastinum was found via thoracoscopy, and a mature teratoma was detected based on the pathological result. Herein we report this case and provide lessons for cardiothoracic surgeons.
The Effectiveness of LDOCE Definitions for Concrete and Abstract Nouns in Headword- and Picture-Identification Tasks
Authors: Kamiński Mariusz , Bilynsky Michael , Szymańska-Czaplak Elżbieta , Kamińska Małgorzata 
Published: September 2021

AbstractLDOCE uses a defining vocabulary to make their definitions intelligible to the user. Critics claim this policy may result in imprecise definitions, something especially noticeable in certain concrete and abstract words that are difficult to define by a definition only. This paper examines to what extent LDOCE definitions of such words help learners identify the objects and words being defined. In our experiment on 381 learners of English as a foreign language, three groups of participants viewed different definition types: simplified definitions of LDOCE, unsimplified definitions of MWC, and definitions written in the learners’ mother tongue (UDPL/TR). The results show that the LDOCE definitions proved significantly more useful in the identification tasks than the definitions in MWC, and slightly more useful than in UDPL/TR. Learners with a limited receptive vocabulary size (RVS) did not benefit from LDOCE as much as high-RVS users.
Robust recovery of sparse non-negative weights from mixtures of positive-semi-definite matrices
Authors: Jaensch Fabian , Jung Peter 
Published: September 2021

AbstractWe consider a structured estimation problem where an observed matrix is assumed to be generated as an $s$-sparse linear combination of $N$ given $n\times n$ positive-semi-definite matrices. Recovering the unknown $N$-dimensional and $s$-sparse weights from noisy observations is an important problem in various fields of signal processing and also a relevant preprocessing step in covariance estimation. We will present related recovery guarantees and focus on the case of non-negative weights. The problem is formulated as a convex program and can be solved without further tuning. Such robust, non-Bayesian and parameter-free approaches are important for applications where prior distributions and further model parameters are unknown. Motivated by explicit applications in wireless communication, we will consider the particular rank-one case, where the known matrices are outer products of iid. zero-mean sub-Gaussian $n$-dimensional complex vectors. We show that, for given $n$ and $N$, one can recover non-negative $s$-sparse weights with a parameter-free convex program once $s\leq O(n^2 / \log ^2(N/n^2)$. Our error estimate scales linearly in the instantaneous noise power whereby the convex algorithm does not need prior bounds on the noise. Such estimates are important if the magnitude of the additive distortion depends on the unknown itself.
Quasi feedback forms for differential-algebraic systems
Authors: Berger Thomas , Ilchmann Achim , Trenn Stephan 
Published: September 2021

Abstract
We investigate feedback forms for linear time-invariant systems described by differential-algebraic equations. Feedback forms are representatives of certain equivalence classes. For example, state space transformations, invertible transformations from the left and proportional state feedback constitute an equivalence relation. The representative of such an equivalence class, which we call proportional feedback form for the above example, allows to read off relevant system theoretic properties. Our main contribution is to derive a quasi proportional feedback form. This form is advantageous since it provides some geometric insight and is simple to compute, but still allows to read off the relevant structural properties of the control system. We also derive a quasi proportional and derivative feedback form. Similar advantages hold.
A mathematical model of cardiovascular dynamics for the diagnosis and prognosis of hemorrhagic shock
Authors: D’Orsi Laura , Curcio Luciano , Cibella Fabio , Borri Alessandro , Gavish Lilach , Eisenkraft Arik , De Gaetano Andrea 
Published: September 2021

Abstract
A variety of mathematical models of the cardiovascular system have been suggested over several years in order to describe the time-course of a series of physiological variables (i.e. heart rate, cardiac output, arterial pressure) relevant for the compensation mechanisms to perturbations, such as severe haemorrhage. The current study provides a simple but realistic mathematical description of cardiovascular dynamics that may be useful in the assessment and prognosis of hemorrhagic shock. The present work proposes a first version of a differential-algebraic equations model, the model dynamical ODE model for haemorrhage (dODEg). The model consists of 10 differential and 14 algebraic equations, incorporating 61 model parameters. This model is capable of replicating the changes in heart rate, mean arterial pressure and cardiac output after the onset of bleeding observed in four experimental animal preparations and fits well to the experimental data. By predicting the time-course of the physiological response after haemorrhage, the dODEg model presented here may be of significant value for the quantitative assessment of conventional or novel therapeutic regimens. The model may be applied to the prediction of survivability and to the determination of the urgency of evacuation towards definitive surgical treatment in the operational setting.
Lumped parameter models for two-ventricle and healthy and failing extracardiac Fontan circulations
Authors: Doyle Matthew G , Chugunova Marina , Roche S Lucy , Keener James P 
Published: September 2021

Abstract
Fontan circulations are surgical strategies to treat infants born with single ventricle physiology. Clinical and mathematical definitions of Fontan failure are lacking, and understanding is needed of parameters indicative of declining physiologies. Our objective is to develop lumped parameter models of two-ventricle and single-ventricle circulations. These models, their mathematical formulations and a proof of existence of periodic solutions are presented. Sensitivity analyses are performed to identify key parameters. Systemic venous and systolic left ventricular compliances and systemic capillary and pulmonary venous resistances are identified as key parameters. Our models serve as a framework to study the differences between two-ventricle and single-ventricle physiologies and healthy and failing Fontan circulations.
Curvature Estimates and Gap Theorems for Expanding Ricci Solitons
Authors: Chan Pak-Yeung 
Published: September 2021

AbstractWe derive a sharp lower bound for the scalar curvature of non-flat and non-compact expanding gradient Ricci soliton provided that the scalar curvature is non-negative and the potential function is proper. Upper bound for the scalar curvature of expander with nonpositive Ricci curvature will also be given. Furthermore, we provide a sufficient condition for the scalar curvature of expanding soliton being non-negative. Curvature estimates of expanding solitons in dimensions three and four will also be established. As an application, we prove a gap theorem on 3D gradient expander.
On the Defocusing Semilinear Wave Equations in Three Space Dimension with Small Power
Authors: Wei Dongyi , Yang Shiwu 
Published: September 2021

Abstract
By introducing new weighted vector fields as multipliers, we derive quantitative pointwise estimates for solutions of defocusing semilinear wave equation in $\mathbb {R}^{1+3}$ with pure power nonlinearity for all $1&lt;p\leq 2$. Consequently, the solution vanishes on the future null infinity and decays in time polynomially for all $\sqrt {2}&lt;p\leq 2$. This improves the uniform boundedness result of the 2nd author when $\frac {3}{2}&lt;p\leq 2$.
Hyperbolic Equivariants of Rational Maps
Authors: Jacobs Kenneth 
Published: September 2021

AbstractLet $K$ denote either ${\mathbb{R}}$ or ${\mathbb{C}}$. In this article, we study two new equivariants and a new invariant attached to a rational map $f\in K(z)$ under the action of conjugation by ${\operatorname{SL}}_2(K)$. The 1st two equivariants naturally live on real hyperbolic $[K:{\mathbb{Q}}]+1$ space and carry information about the action of $f$ on ${\mathbb{P}}^1(K)$. When $K={\mathbb{C}}$, we study how these objects behave as the map $f$ is iterated; the limits that arise are related to Douady and Earle’s construction of conformal barycenters of measures on $S^2$. We end by giving a description of these objects for maps of degree $d=1$.
The Koopman Representation and Positive Rokhlin Entropy
Authors: Seward Brandon 
Published: September 2021

Abstract
In this paper, we study connections between positive entropy phenomena and the Koopman representation for actions of general countable groups. Following the line of work initiated by Hayes for sofic entropy, we show in a certain precise manner that all positive entropy must come from portions of the Koopman representation that embed into the left-regular representation. We conclude that for actions having completely positive outer entropy, the Koopman representation must be isomorphic to the countable direct sum of the left-regular representation. This generalizes a theorem of Dooley–Golodets for countable amenable groups. As a final consequence, we observe that actions with completely positive outer entropy must be mixing, and when the group is non-amenable they must be strongly ergodic and have spectral gap.
A Density Theorem for the Difference Galois Groups of Regular Singular Mahler Equations
Authors: Poulet Marina 
Published: September 2021

Abstract
The difference Galois theory of Mahler equations is an active research area. The present paper aims at developing the analytic aspects of this theory. We first attach a pair of connection matrices to any regular singular Mahler equation. We then show that these connection matrices can be used to produce a Zariski-dense subgroup of the difference Galois group of any regular singular Mahler equation.
Clinicoepidemiological Observations of Enteric Fever in Infants: Experiences From a Tertiary Care Pediatric Hospital in North India
Authors: Saigal Karnika , Gupta Deepika , Saikia Diganta 
Published: September 2021

Abstract

Background
There is a lack of evident data to explain the true scenario of age-specific enteric fever in India. The current study aimed to evaluate the burden and disease pattern of enteric fever among infants in a tertiary care pediatric hospital.

Methods
A prospective laboratory-based surveillance was conducted from April 2018 to January 2020 at a children’s hospital in North India, under the Surveillance for Enteric Fever in India study. The study included children &lt;1 year of age in whom Salmonella serovar Typhi/Salmonella serovar Paratyphi grew in cultures from blood or sterile body fluid. The key outcome measures included disease spectrum and clinical presentation.

Results
Of the 10 737 blood cultures from infants, 26 were positive for S. Typhi or S. Paratyphi. The majority of cases occurred in infants aged 6–12 months, with the youngest being 1 month old. Fever with abdominal pain and diarrhea were the common symptoms, with 46% of infants requiring inpatient care. All of the isolates were susceptible to ceftriaxone. Third-generation cephalosporins were used as the first-line therapy for hospitalized infants. The average duration of fever was 8.6 days. The overall case-fatality rate among infants with enteric fever was 7.4%.

Conclusions
Enteric fever is a major contributor to disease and death among children. Robust surveillance studies are required to understand the true disease burden.