bluuebunny/crossref_metadata_2025 huggingface dataset:
Correlation functions of spinor current multiplets in $$ \mathcal{N} $$ = 1 superconformal theory
Authors: Buchbinder Evgeny I. , Hutomo Jessica , Kuzenko Sergei M.
Published: July 2021

Abstract

We consider $$ \mathcal{N} $$
N
= 1 superconformal field theories in four dimensions possessing an additional conserved spinor current multiplet Sα and study three-point functions involving such an operator. A conserved spinor current multiplet naturally exists in superconformal theories with $$ \mathcal{N} $$
N
= 2 supersymmetry and contains the current of the second supersymmetry. However, we do not assume $$ \mathcal{N} $$
N
= 2 supersymmetry. We show that the three-point function of two spinor current multiplets and the $$ \mathcal{N} $$
N
= 1 supercurrent depends on three independent tensor structures and, in general, is not contained in the three-point function of the $$ \mathcal{N} $$
N
= 2 supercurrent. It then follows, based on symmetry considerations only, that the existence of one more Grassmann odd current multiplet in $$ \mathcal{N} $$
N
= 1 superconformal field theory does not necessarily imply $$ \mathcal{N} $$
N
= 2 superconformal symmetry.
Asymptotic Stability of Minkowski Space-Time with Non-compactly Supported Massless Vlasov Matter
Authors: Bigorgne Léo , Fajman David , Joudioux Jérémie , Smulevici Jacques , Thaller Maximilian
Published: July 2021

We prove the global asymptotic stability of the Minkowski space for the massless Einstein–Vlasov system in wave coordinates. In contrast with previous work on the subject, no compact support assumptions on the initial data of the Vlasov field in space or the momentum variables are required. In fact, the initial decay invis optimal. The present proof is based on vector field and weighted vector field techniques for Vlasov fields, as developed in previous work of Fajman, Joudioux, and Smulevici, and heavily relies on several structural properties of the massless Vlasov equation, similar to the null and weak null conditions. To deal with the weak decay rate of the metric, we propagate well-chosen hierarchized weighted energy norms which reflect the strong decay properties satisfied by the particle density far from the light cone. A particular analytical difficulty arises at the top order, when we do not have access to improved pointwise decay estimates for certain metric components. This difficulty is resolved using a novel hierarchy in the massless Einstein–Vlasov system, which exploits the propagation of different growth rates for the energy norms of different metric components.
Rapid quantification of fatty acids in plant oils and biological samples by LC-MS
Authors: Koch Elisabeth , Wiebel Michelle , Hopmann Carolin , Kampschulte Nadja , Schebb Nils Helge
Published: July 2021

Analysis of fatty acids (FA) in food and biological samples such as blood is indispensable in modern life sciences. We developed a rapid, sensitive and comprehensive method for the quantification of 41 saturated and unsaturated fatty acids by means of LC-MS. Optimized chromatographic separation of isobaric analytes was carried out on a C8 reversed phase analytical column (100 × 2.1 mm, 2.6 μm core–shell particle) with a total run time of 15 min with back pressure lower than 300 bar. On an old triple quadrupole instrument (3200, AB Sciex), pseudo selected reaction monitoring mode was used for quantification of the poorly fragmenting FA, yielding limits of detection of 5–100 nM. Sample preparation was carried out by removal of phospholipids and triglycerides by solid-phase extraction (non-esterified fatty acids in oils) or saponification in iso-propanol (fatty acyls). This is not only a rapid strategy for quantification of fatty acyls, but allows the direct combination with the LC-MS-based analysis of fatty acid oxidation products (eicosanoids and other oxylipins) from the same sample. The concentrations of fatty acyls determined by means of LC-MS were consistent with those from GC-FID analysis demonstrating the accuracy of the developed method. Moreover, the method shows high precisions with a low intra-day (≤ 10% for almost all fatty acids in plasma and ≤ 15% in oils) and inter-day as well as inter-operator variability (< 20%). The method was successfully applied on human plasma and edible oils. The possibility to quantify non-esterified fatty acids in samples containing an excess of triacylglycerols and phospholipids is a major strength of the described approach allowing to gain new insights in the composition of biological samples.

Graphical abstract
A Positivity-preserving Conservative Semi-Lagrangian Multi-moment Global Transport Model on the Cubed Sphere
Authors: Tang Jie , Chen Chungang , Shen Xueshun , Xiao Feng , Li Xingliang
Published: July 2021

A positivity-preserving conservative semi-Lagrangian transport model by multi-moment finite volume method has been developed on the cubed-sphere grid. Two kinds of moments (i.e., point values (PV moment) at cell interfaces and volume integrated average (VIA moment) value) are defined within a single cell. The PV moment is updated by a conventional semi-Lagrangian method, while the VIA moment is cast by the flux form formulation to assure the exact numerical conservation. Different from the spatial approximation used in the CSL2 (conservative semi-Lagrangian scheme with second order polynomial function) scheme, a monotonic rational function which can effectively remove non-physical oscillations is reconstructed within a single cell by the PV moments and VIA moment. To achieve exactly positive-definite preserving, two kinds of corrections are made on the original conservative semi-Lagrangian with rational function (CSLR) scheme. The resulting scheme is inherently conservative, non-negative, and allows a Courant number larger than one. Moreover, the spatial reconstruction can be performed within a single cell, which is very efficient and economical for practical implementation. In addition, a dimension-splitting approach coupled with multi-moment finite volume scheme is adopted on cubed-sphere geometry, which benefitsthe implementation of the 1D CSLR solver with large Courant number. The proposed model is evaluated by several widely used benchmark tests on cubed-sphere geometry. Numerical results show that the proposed transport model can effectively remove nonphysical oscillations and preserve the numerical non-negativity, and it has the potential to transport the tracers accurately in a real atmospheric model.
Synoptic conditions controlling the seasonal onset and days of heatwaves over Korea
Authors: Choi Woosuk , Ho Chang-Hoi , Jung Jiyoung , Chang Minhee , Ha Kyung-Ja
Published: July 2021

As global warming gets worse, the extreme heat exposure time is expected to increase. Considering that the heatwave damages increased by the accumulation of heat stress, it is important to understand the heatwave onset and number of heatwave days (HWDs). Here, we show that the end of East Asian summer monsoon activity (i.e., Changma retreat date, CRD) could be an indicator in determining the onset of the heatwave, and the barotropic structure induced by the circumglobal and Pacific–Japan teleconnections is a key factor in lengthening the number of HWDs in Korea. The onset of the heatwave is delayed when CRD belated than the climatology late over Korea due to sufficient moisture transportation between the edge of western North Pacific subtropical high and cold polar air mass in July. The number of HWDs from July through August over Korea shows a positive linear relationship with the synoptic stagnation index because the upper-layer anticyclone associated with stagnation is formed around Korea by zonal wave activity. Barotropic anticyclone stabilizes the atmosphere and increases the number of clear sky days, which possibly leads to hot days. Fewer HWDs are observed when there is baroclinic instability due to strong upper-level jet stream and synoptic-scale weather systems move smoothly. By identifying the meteorological mechanism of heatwave occurrence and favorable conditions for sustained hot days over Korea, our results are eventually able to contribute to reducing damages caused by heatwaves.
Assessment of the Canary current upwelling system in a regionally coupled climate model
Authors: Vazquez Ruben , Parras-Berrocal Ivan , Cabos William , Sein Dmitry V. , Mañanes Rafael , Izquierdo Alfredo
Published: July 2021

The Canary current upwelling is one of the major eastern boundary coastal upwelling systems in the world, bearing a high productive ecosystem and commercially important fisheries. The Canary current upwelling system (CCUS) has a large latitudinal extension, usually divided into upwelling zones with different characteristics. Eddies, filaments and other mesoscale processes are known to have an impact in the upwelling productivity, thus for a proper representation of the CCUS and high horizontal resolution are required. Here we assess the CCUS present climate in the atmosphere–ocean regionally coupled model. The regional coupled model presents a global oceanic component with increased horizontal resolution along the northwestern African coast, and its performance over the CCUS is assessed against relevant reanalysis data sets and compared with an ensemble of global climate models (GCMs) and an ensemble of atmosphere-only regional climate models (RCMs) in order to assess the role of the horizontal resolution. The coupled system reproduces the larger scale pattern of the CCUS and its latitudinal and seasonal variability over the coastal band, improving the GCMs outputs. Moreover, it shows a performance comparable to the ensemble of RCMs in representing the coastal wind stress and near-surface air temperature fields, showing the impact of the higher resolution and coupling for CCUS climate modelling. The model is able of properly reproducing mesoscale structures, being able to simulate the upwelling filaments events off Cape Ghir, which are not well represented in most of GCMs. Our results stress the ability of the regionally coupled model to reproduce the larger scale as well as mesoscale processes over the CCUS, opening the possibility to evaluate the climate change signal there with increased confidence.
Seizure-mediated iron accumulation and dysregulated iron metabolism after status epilepticus and in temporal lobe epilepsy
Authors: Zimmer Till S. , David Bastian , Broekaart Diede W. M. , Schidlowski Martin , Ruffolo Gabriele , Korotkov Anatoly , van der Wel Nicole N. , van Rijen Peter C. , Mühlebner Angelika , van Hecke Wim , Baayen Johannes C. , Idema Sander , François Liesbeth , van Eyll Jonathan , Dedeurwaerdere Stefanie , Kessels Helmut W. , Surges Rainer , Rüber Theodor , Gorter Jan A. , Mills James D. , van Vliet Erwin A. , Aronica Eleonora
Published: July 2021

Neuronal dysfunction due to iron accumulation in conjunction with reactive oxygen species (ROS) could represent an important, yet underappreciated, component of the epileptogenic process. However, to date, alterations in iron metabolism in the epileptogenic brain have not been addressed in detail. Iron-related neuropathology and antioxidant metabolic processes were investigated in resected brain tissue from patients with temporal lobe epilepsy and hippocampal sclerosis (TLE-HS), post-mortem brain tissue from patients who died after status epilepticus (SE) as well as brain tissue from the electrically induced SE rat model of TLE. Magnetic susceptibility of the presumed seizure-onset zone from three patients with focal epilepsy was compared during and after seizure activity. Finally, the cellular effects of iron overload were studied in vitro using an acute mouse hippocampal slice preparation and cultured human fetal astrocytes. While iron-accumulating neurons had a pyknotic morphology, astrocytes appeared to acquire iron-sequestrating capacity as indicated by prominent ferritin expression and iron retention in the hippocampus of patients with SE or TLE. Interictal to postictal comparison revealed increased magnetic susceptibility in the seizure-onset zone of epilepsy patients. Post-SE rats had consistently higher hippocampal iron levels during the acute and chronic phase (when spontaneous recurrent seizures are evident). In vitro, in acute slices that were exposed to iron, neurons readily took up iron, which was exacerbated by induced epileptiform activity. Human astrocyte cultures challenged with iron and ROS increased their antioxidant and iron-binding capacity, but simultaneously developed a pro-inflammatory phenotype upon chronic exposure. These data suggest that seizure-mediated, chronic neuronal iron uptake might play a role in neuronal dysfunction/loss in TLE-HS. On the other hand, astrocytes sequester iron, specifically in chronic epilepsy. This function might transform astrocytes into a highly resistant, pro-inflammatory phenotype potentially contributing to pro-epileptogenic inflammatory processes.
Episodic ataxia and severe infantile phenotype in spinocerebellar ataxia type 14: expansion of the phenotype and novel mutations
Authors: De Michele Giovanna , Galatolo Daniele , Galosi Serena , Mignarri Andrea , Silvestri Gabriella , Casali Carlo , Leuzzi Vincenzo , Ricca Ivana , Barghigiani Melissa , Tessa Alessandra , Cioffi Ettore , Caputi Caterina , Riso Vittorio , Dotti Maria Teresa , Saccà Francesco , De Michele Giuseppe , Cocozza Sirio , Filla Alessandro , Santorelli Filippo M.
Published: July 2021

Introduction

Spinocerebellar ataxia type 14 (SCA14) is a dominantly inherited neurological disorder characterized by slowly progressive cerebellar ataxia. SCA14 is caused by mutations in PRKCG, a gene encoding protein kinase C gamma (PKCγ), a master regulator of Purkinje cells development.

Methods

We performed next-generation sequencing targeted resequencing panel encompassing 273 ataxia genes in 358 patients with genetically undiagnosed ataxia.

Results

We identified fourteen patients in ten families harboring nine pathogenic heterozygous variants in PRKCG, seven of which were novel. We encountered four patients with not previously described phenotypes: one with episodic ataxia, one with a spastic paraparesis dominating her clinical manifestations, and two children with an unusually severe phenotype.

Conclusions

Our study broadens the genetic and clinical spectrum of SCA14.
Knockdown of the prognostic cancer stem cell marker Musashi-1 decreases radio-resistance while enhancing apoptosis in hormone receptor-positive breast cancer cells via p21WAF1/CIP1
Authors: Troschel Fabian M. , Palenta Heike , Borrmann Katrin , Heshe Kristin , Hua San Hue , Yip George W. , Kiesel Ludwig , Eich Hans Theodor , Götte Martin , Greve Burkhard
Published: July 2021

Purpose

While the stem cell marker Musashi-1 (MSI-1) has been identified as a key player in a wide array of malignancies, few findings exist on its prognostic relevance and relevance for cancer cell death and therapy resistance in breast cancer.

Methods

First, we determined prognostic relevance of MSI-1 in database analyses regarding multiple survival outcomes. To substantiate findings, MSI-1 was artificially downregulated in MCF-7 breast cancer cells and implications for cancer stem cell markers, cell apoptosis and apoptosis regulator p21, proliferation and radiation response were analyzed via flow cytometry and colony formation. Radiation-induced p21 expression changes were investigated using a dataset containing patient samples obtained before and after irradiation and own in vitro experiments.

Results

MSI-1 is a negative prognostic marker for disease-free and distant metastasis-free survival in breast cancer and tends to negatively influence overall survival. MSI-1 knockdown downregulated stem cell gene expression and proliferation, but increased p21 levels and apoptosis. Similar to the MSI-1 knockdown effect, p21 expression was strongly increased after irradiation and was expressed at even higher levels in MSI-1 knockdown cells after irradiation. Finally, combined use of MSI-1 silencing and irradiation reduced cancer cell survival.

Conclusion

MSI-1 is a prognostic marker in breast cancer. MSI-1 silencing downregulates proliferation while increasing apoptosis. The anti-proliferation mediator p21 was upregulated independently after both MSI-1 knockdown and irradiation and even more after both treatments combined, suggesting synergistic potential. Radio-sensitization effects after combining radiation and MSI-1 knockdown underline the potential of MSI-1 as a therapeutic target.
De novo lupus-like glomerulonephritis after pediatric non-kidney organ transplantation
Authors: Farkas-Skiles Cristina M. , Ettenger Robert B. , Zuckerman Jonathan E. , Pearl Meghan , Venick Robert S. , Weng Patricia L.
Published: July 2021

Background

We propose a novel clinically significant finding, de novo lupus-like glomerulonephritis (DNLLGN), in patients with autoantibodies and kidney abnormalities in pediatric liver transplant (LT) and intestinal inclusive transplants (ITx).

Methods

We describe the clinical, serologic, and histopathologic presentation and kidney outcomes in eight patients from our center found to have DNLLGN on kidney biopsy.

Results

Pediatric recipients of non-kidney solid organ transplants developed an unusual de novo immune complex glomerulonephritis with morphologic similarity to lupus nephritis. Six had isolated LT (0.9% of all pediatric LT at our center) and two had ITx (2.1% of all ITx). Five (63%) presented with nephrotic syndrome. Five patients had autoantibodies. Patients underwent kidney biopsy at a mean of 11.5 years in LT and 2.8 years in ITx after the index transplant. Biopsies demonstrated changes similar to focal or diffuse active lupus. Follow-up eGFR at a mean of 6 years after biopsy showed a mean decrease of 30 ml/min/1.73 m2 in all patients (p = 0.11).

Conclusions

DNLLGN has not been previously recognized in this clinical setting, yet 8 kidney biopsies from pediatric recipients of LT and ITx at our center in 25 years demonstrated this finding. DNLLGN appears to be an under-reported phenomenon of clinical significance.

Graphical abstract
Caregiver strain in progressive supranuclear palsy and corticobasal syndromes
Authors: Kellermair Lukas , Fuchs Alexandra , Eggers Christian , Schwingenschuh Petra , Kögl Mariella , Fellner Franz , Forstner Thomas , Mangesius Stephanie , Guger Michael , Ransmayr Gerhard
Published: July 2021

Progressive supranuclear palsy (PSP) and corticobasal syndrome (CBS) progress relentlessly and lead to a need for care. Caregiving is often burdensome. Little is known about the course of caregiver burden (CB) in PSP and CBS patients. Longitudinal analysis of CB in family members caring for PSP and CBS patients. Single-center longitudinal pilot study in 68 newly diagnosed patients with probable PSP and CBS (52 Richardson’s syndrome; 1 progressive gait freezing of PSP; 15 CBS). Demographic, educational, occupational parameters, family status, motor functions (UPDRSIII, Hoehn and Yahr Score, Tinetti) and neuropsychological performance (CERAD Plus, Frontal Assessment Battery) were assessed, as well as behavioral and neuropsychiatric impairments (Frontal Behavioral Inventory, Neuropsychiatric Inventory), activities of daily living (ADL) and caregiver burden using the Caregiver Strain Index (CSI), in most patients also the Zarit Burden Interview (ZBI). Patients were followed up every 6 months for up to 2 years. Caregivers reported mild to moderate CB at baseline, which increased by 25–30% in 2 years and was significantly greater in PSP than in CBS. Risk for mental health problems increased over time, especially in female caregivers (depression). Important patient-related factors were apathy, aspontaneity, depression, irritability, disorganization, poor judgment, impairment of language, impairments in ADL, a high educational level of the patient and close family relationship. Behavioral symptoms and impaired ADL are the main patient-related factors of CB in PSP and CBS. CB can be severe and needs to be assessed repeatedly from the time of diagnosis to provide comprehensive support.
On the Inverse Source Identification Problem in $L^{\infty }$ for Fully Nonlinear Elliptic PDE
Authors: Ayanbayev Birzhan , Katzourakis Nikos
Published: July 2021

In this paper we generalise the results proved in N. Katzourakis (SIAM J. Math. Anal.51, 1349–1370, 2019) by studying the ill-posed problem of identifying the source of a fully nonlinear elliptic equation. We assume Dirichlet data and some partial noisy information for the solution on a compact set through a fully nonlinear observation operator. We deal with the highly nonlinear nonconvex nature of the problem and the lack of weak continuity by introducing a two-parameter Tykhonov regularisation with a higher orderL2“viscosity term” for the$L^{\infty }$L∞minimisation problem which allows to approximate by weakly lower semicontinuous cost functionals.
Past, present and future suitable areas for the relict tree Pterocarya fraxinifolia (Juglandaceae): Integrating fossil records, niche modeling, and phylogeography for conservation
Authors: Song Yi-Gang , Walas Łukasz , Pietras Marcin , Sâm Hoàng Văn , Yousefzadeh Hamed , Ok Tolga , Farzaliyev Vahid , Worobiec Grzegorz , Worobiec Elżbieta , Stachowicz-Rybka Renata , Boratyński Adam , Boratyńska Krystyna , Kozlowski Gregor , Jasińska Anna K.
Published: July 2021

Pterocarya fraxinifolia, native to the southern Caucasus and adjacent areas, has been widely introduced in Europe. In this study, we investigate the following: (1) How did its current distribution form? (2) What are the past, current, and future suitable habitats of P. fraxinifolia? (3) What is the best conservation approach? Ecological niche modeling was applied to determine its climatic demands and project the distribution of climatically suitable areas during three periods of past, current, and future (2070) time. Then, an integrated analysis of fossil data was performed. Massive expansion of Pterocarya species between the Miocene and Pliocene facilitated the arrival of P. fraxinifolia to the southern Caucasus. The Last Glacial Maximum played a vital role in its current fragmented spatial distribution in the Euxinian and Hyrcanian regions with lower elevations, and Caucasian and Irano-Turanian regions with higher elevations. Climatic limiting factors were very different across these four regions. Future climate change will create conditions for the expansion of this species in Europe. Human activities significantly decreased the suitable area for P. fraxinifolia, especially in the Euxinian, Hyrcanian, and Irano-Turanian regions. Considering genetic diversity, climate vulnerability, and land utilization, the Euxinian, Hyrcanian, and Irano-Turanian regions have been recognized as conservation priority areas for P. fraxinifolia.
Large-Scale Synoptic Systems and Fog During the C-FOG Field Experiment
Authors: Dorman Clive E. , Hoch Sebastian W. , Gultepe Ismail , Wang Qing , Yamaguchi Ryan T. , Fernando H. J. S. , Krishnamurthy Raghavendra
Published: July 2021

The goal of this work is to summarize synoptic meteorological conditions during the Coastal Fog (C-FOG) field project that took place onshore and offshore of the Avalon Peninsula, Newfoundland, from 25 August until 8 October 2018. Visibility was measured at three locations at the Ferryland supersite that are about 1 km from each other, and at two additional sites 66 and 76 km to the north. Supporting meteorological measurements included surface winds, air temperature, humidity, pressure, radiation, cloud-base height, and atmospheric thermodynamic profiles from radiosonde soundings. Statistics are presented for surface measurements during fog events including turbulence kinetic energy, net longwave radiation, visibility, and precipitation. Eleven fog events are observed at Ferryland. Each significant fog event is related to a large-scale cyclonic system. The longest fog event is due to interaction of a northern deep low and a tropical cyclone. Fog occurrence is also examined across Atlantic Canada by including Sable Island, Yarmouth, Halifax, and Sydney. It is concluded that at Ferryland, all significant fog events occur under a cyclonic system while at Sable Island all significant fog events occur under both cyclonic and anticyclonic systems. The fog-formation mechanism involves cloud lowering and stratus broadening or only stratus broadening for the cyclonic systems while for the anticyclonic systems it is stratus broadening or radiation. Although widely cited as the main cause of fog in Atlantic Canada, advection fog is not found to be the primary or sole fog type in the events examined.
Exploring Prison Misconduct and the Factors Influencing Rule Infraction in Northern Ireland
Authors: Butler Michelle , McNamee Catherine B. , Kelly Dominic
Published: July 2021

Research has linked prison misconduct to reoffending and re-entry experiences, yet no studies have sought to examine the factors influencing misconduct in Northern Ireland or if these factors operate differently for separated prisoners (those claiming their offences are politically motivated and demanding to be held separately to the rest of the prison population) compared to the general prison population. This study addresses this gap by examining the characteristics related to misconduct in Northern Ireland. Using a cross-sectional sample of 892 imprisoned adult men, the findings indicate that increased involvement in misconduct is associated with multiple needs. Younger age, racial/ethnic identity, accommodation issues, addiction, impairments, property offences, previous incarceration, prison complaints, not having a drug test and engagement/suspected engagement in serious self-harm while imprisoned increased the risk of misconduct. Reporting a nationality other than British, Irish or Northern Irish, passing prison drug tests and prison visitation lowered the risk of misconduct. Factors were found to operate in a similar manner for both the general prison population and separated prisoners, with the exception of prison complaints. Given the link between misconduct and reoffending, it is argued that specialist supports are required to address the multiple needs of those who frequently engage in misconduct if efforts to reduce recidivism are to be enhanced.
Molecular and Crystal Structures of Some Fluorocymantrenes
Authors: Sünkel Karlheinz , Klein-Heßling Christian
Published: July 2021

The crystal and molecular structures of the fluorocymantrenes [(C5H4F)Mn(CO)3] and [(C5H5−nFn)Mn (CO)2(PPh3)] (n = 1–3) have been studied. The influence of the phosphine for carbonyl substitution on the bond parameters is larger than the influence of the increasing fluorine content. In most cases the Mn → P vector is in a transoid position relative to the fluorine substituents, and therefore the conformational parameters of the PPh3 propeller are in these cases very similar. The crystal structures show many intermolecular C–H⋯O hydrogen bonds and only very few C–H⋯F hydrogen bonds.

Graphic Abstract

The influence of the phosphine for carbonyl substitution on the bond parameters of the fluorocymantrenes [(C5H4F)Mn(CO)3] and [(C5H5−nFn)Mn (CO)2(PPh3)] (n = 1–3) is larger than the influence of the increasing fluorine content.
Fast Reaction Limits via $$\Gamma $$-Convergence of the Flux Rate Functional
Authors: Peletier Mark A. , Renger D. R. Michiel
Published: July 2021

We study the convergence of a sequence of evolution equations for measures supported on the nodes of a graph. The evolution equations themselves can be interpreted as the forward Kolmogorov equations of Markov jump processes, or equivalently as the equations for the concentrations in a network of linear reactions. The jump rates or reaction rates are divided in two classes; ‘slow’ rates are constant, and ‘fast’ rates are scaled as $$1/\epsilon $$

1
/
ϵ

, and we prove the convergence in the fast-reaction limit $$\epsilon \rightarrow 0$$

ϵ
→
0

. We establish a $$\Gamma $$
Γ
-convergence result for the rate functional in terms of both the concentration at each node and the flux over each edge (the level-2.5 rate function). The limiting system is again described by a functional, and characterises both fast and slow fluxes in the system. This method of proof has three advantages. First, no condition of detailed balance is required. Secondly, the formulation in terms of concentration and flux leads to a short and simple proof of the $$\Gamma $$
Γ
-convergence; the price to pay is a more involved compactness proof. Finally, the method of proof deals with approximate solutions, for which the functional is not zero but small, without any changes.
Morse Theory for S-balanced Configurations in the Newtonian n-body Problem
Authors: Asselle Luca , Portaluri Alessandro
Published: July 2021

For the Newtonian (gravitational) n-body problem in the Euclidean d-dimensional space, the simplest possible solutions are provided by those rigid motions (homographic solutions) in which each body moves along a Keplerian orbit and the configuration of the n-body is a (constant up to rotations and scalings) central configuration. For $$d\le 3$$

d
≤
3

, the only possible homographic motions are those given by central configurations. For $$d \ge 4$$

d
≥
4

instead, new possibilities arise due to the higher complexity of the orthogonal group $$\mathrm {O}(d)$$

O
(
d
)

, as observed by Albouy and Chenciner (Invent Math 131(1):151–184, 1998). For instance, in $$\mathbb {R}^4$$

R

4

it is possible to rotate in two mutually orthogonal planes with different angular velocities. This produces a new balance between gravitational forces and centrifugal forces providing new periodic and quasi-periodic motions. So, for $$d\ge 4$$

d
≥
4

there is a wider class of S-balanced configurations (containing the central ones) providing simple solutions of the n-body problem, which can be characterized as well through critical point theory. In this paper, we first provide a lower bound on the number of balanced (non-central) configurations in $$\mathbb {R}^d$$

R

d

, for arbitrary $$d\ge 4$$

d
≥
4

, and establish a version of the $$45^\circ $$

45
∘

-theorem for balanced configurations, thus answering some of the questions raised in Moeckel (Central configurations, 2014). Also, a careful study of the asymptotics of the coefficients of the Poincaré polynomial of the collision free configuration sphere will enable us to derive some rather unexpected qualitative consequences on the count of S-balanced configurations. In the last part of the paper, we focus on the case $$d=4$$

d
=
4

and provide a lower bound on the number of periodic and quasi-periodic motions of the gravitational n-body problem which improves a previous celebrated result of McCord (Ergodic Theory Dyn Syst 16:1059–1070, 1996).
Spectral Shape Recovery and Analysis Via Data-driven Connections
Authors: Marin Riccardo , Rampini Arianna , Castellani Umberto , Rodolà Emanuele , Ovsjanikov Maks , Melzi Simone
Published: July 2021

We introduce a novel learning-based method to recover shapes from their Laplacian spectra, based on establishing and exploring connections in a learned latent space. The core of our approach consists in a cycle-consistent module that maps between a learned latent space and sequences of eigenvalues. This module provides an efficient and effective link between the shape geometry, encoded in a latent vector, and its Laplacian spectrum. Our proposed data-driven approach replaces the need for ad-hoc regularizers required by prior methods, while providing more accurate results at a fraction of the computational cost. Moreover, these latent space connections enable novel applications for both analyzing and controlling the spectral properties of deformable shapes, especially in the context of a shape collection. Our learning model and the associated analysis apply without modifications across different dimensions (2D and 3D shapes alike), representations (meshes, contours and point clouds), nature of the latent space (generated by an auto-encoder or a parametric model), as well as across different shape classes, and admits arbitrary resolution of the input spectrum without affecting complexity. The increased flexibility allows us to address notoriously difficult tasks in 3D vision and geometry processing within a unified framework, including shape generation from spectrum, latent space exploration and analysis, mesh super-resolution, shape exploration, style transfer, spectrum estimation for point clouds, segmentation transfer and non-rigid shape matching.
Slowing down as we age: aging of the cardiac pacemaker’s neural control
Authors: Choi Sabrina , Baudot Matthias , Vivas Oscar , Moreno Claudia M.
Published: July 2021

The cardiac pacemaker ignites and coordinates the contraction of the whole heart, uninterruptedly, throughout our entire life. Pacemaker rate is constantly tuned by the autonomous nervous system to maintain body homeostasis. Sympathetic and parasympathetic terminals act over the pacemaker cells as the accelerator and the brake pedals, increasing or reducing the firing rate of pacemaker cells to match physiological demands. Despite the remarkable reliability of this tissue, the pacemaker is not exempt from the detrimental effects of aging. Mammals experience a natural and continuous decrease in the pacemaker rate throughout the entire lifespan. Why the pacemaker rhythm slows with age is poorly understood. Neural control of the pacemaker is remodeled from birth to adulthood, with strong evidence of age-related dysfunction that leads to a downshift of the pacemaker. Such evidence includes remodeling of pacemaker tissue architecture, alterations in the innervation, changes in the sympathetic acceleration and the parasympathetic deceleration, and alterations in the responsiveness of pacemaker cells to adrenergic and cholinergic modulation. In this review, we revisit the main evidence on the neural control of the pacemaker at the tissue and cellular level and the effects of aging on shaping this neural control.
Looking back at “our science” and “our history”: an exploration of Korean preservice science teachers’ encounters with East Asian history of science
Authors: Park Wonyong , Song Jinwoong
Published: July 2021

Despite the long-standing interest among science educators in using history of science in science teaching, little has been discussed around whether and how non-Western histories of science could be incorporated into science education. This study considers some opportunities and challenges of addressing East Asian history of science (EAHOS) in the science teacher education context, drawing on postcolonial science studies and global history of science. Eight undergraduate preservice science teachers (PSTs) participated in sessions on EAHOS. Our aim was to investigate the PSTs’ perceptions relating to the nature of EAHOS and its relevance to science teaching. Using interviews and reflective essays, we explore the tension coming from their dual positions as science teachers and East Asian people as they entered into the unfamiliar territory of EAHOS. When they were considering themselves specifically as science teachers, they tended to focus on the aspects of EAHOS as knowledge and concluded that it has little to do with achieving the aims of science teaching because is not part of modern science. On the contrary, when they were talking about their roles as teachers in general, they were able to come up with several educational benefits that EAHOS can offer to students, particularly in its relation to worldview and history. Additionally, several mixed feelings were expressed about the way EAHOS is often portrayed as “our” history about “our” science. Overall, the experience of exploring and discussing EAHOS provided the PSTs with an opportunity to critically reflect on science education and their responsibility as teachers in the context of broader society and culture.
Archetypes of Driver Combinations Leading to Foreign Market Exit: An Investigation into European Grocery Retailing
Authors: Schmid David , de Thomas Wagner Finn , Morschett Dirk
Published: July 2021

Existing research into retailers’ foreign market exits has uncovered a number of drivers that lead multinational retailers to divest from certain countries. While scholars have investigated these drivers in isolation from one another, combinations of drivers that affect divestment decisions simultaneously remain under-researched despite scholars having indicated their importance and having called for a detailed, more holistic analysis. In this study, using a case study approach and qualitative content analysis of a wide variety of publicly available contemporary documents from different perspectives and experts, we investigate the drivers leading to all 32 country exits of the 50 largest grocery retailers in Europe in the 5-year period between 2014 and 2018. In line with previous research, the study shows the most frequent exit drivers are a low performance of the subsidiary, a low performance of the parent company, and a strategic refocus of the parent company. However, we demonstrate that for most exits, combinations of multiple interrelated drivers at the subsidiary level, the host-country level, and the parent level have a joint influence on retailers’ decisions to exit foreign markets. We also show that exits often include both failure-related drivers and strategy-related drivers. Furthermore, using the configurational approach, we identify exemplary combinations of market exit drivers that occur frequently and propose five archetypes of such combinations that suffice to explain all market exits in the dataset. For future research, we propose extending our typology through the application of a similar approach to different contexts and to use quantitative research based on the qualitative findings to generate more generalizable results.
Using citizen science data to monitor the Sustainable Development Goals: a bottom-up analysis
Authors: Ballerini Laura , Bergh Sylvia I.
Published: July 2021

Official data are not sufficient for monitoring the United Nations Sustainable Development Goals (SDGs): they do not reach remote locations or marginalized populations and can be manipulated by governments. Citizen science data (CSD), defined as data that citizens voluntarily gather by employing a wide range of technologies and methodologies, could help to tackle these problems and ultimately improve SDG monitoring. However, the link between CSD and the SDGs is still understudied. This article aims to develop an empirical understanding of the CSD-SDG link by focusing on the perspective of projects which employ CSD. Specifically, the article presents primary and secondary qualitative data collected on 30 of these projects and an explorative comparative case study analysis. It finds that projects which use CSD recognize that the SDGs can provide a valuable framework and legitimacy, as well as attract funding, visibility, and partnerships. But, at the same time, the article reveals that these projects also encounter several barriers with respect to the SDGs: a widespread lack of knowledge of the goals, combined with frustration and political resistance towards the UN, may deter these projects from contributing their data to the SDG monitoring apparatus.
New examples of subsets of c with the FPP and stability of the FPP in hyperconvex spaces
Authors: Espínola-García Rafael , Japón María , Souza Daniel
Published: July 2021

The purpose of this work is two-fold. On the one side, we focus on the space of real convergent sequences c where we study non-weakly compact sets with the fixed point property. Our approach brings a positive answer to a recent question raised by Gallagher et al. in (J Math Anal Appl 431(1):471–481, 2015). On the other side, we introduce a new metric structure closely related to the notion of relative uniform normal structure, for which we show that it implies the fixed point property under adequate conditions. This will provide some stability fixed point results in the context of hyperconvex metric spaces. As a particular case, we will prove that the set $$M=[-1,1]^\mathbb {N}$$

M
=

[
-
1
,
1
]

N

has the fixed point property for d-nonexpansive mappings where $$d(\cdot ,\cdot )$$

d
(
·
,
·
)

is a metric verifying certain restrictions. Applications to some Nakano-type norms are also given.
Crowdsourcing and open innovation: a systematic literature review, an integrated framework and a research agenda
Authors: Cricelli Livio , Grimaldi Michele , Vermicelli Silvia
Published: July 2021

In recent years, Open Innovation (OI) and crowdsourcing have been very popular topics in the innovation management literature, attracting significant interest and attention, and inspiring a rich production of publications. Although these two topics share common themes and address similar managerial challenges, to the best of our knowledge, there is no systematic literature review that digs deep into the intersection of both fields. To fill in this gap a joint review of crowdsourcing and OI topics is both timely and of interest. Therefore, the main objective of this study is to carry out a comprehensive, systematic, and objective review of academic research to help shed light on the relationship between OI and crowdsourcing. For this purpose, we reviewed the literature published on these two topics between 2008 and 2019, applying two bibliometric techniques, co-citation and co-word analysis. We obtained the following results: (i) we provide a qualitative analysis of the emerging and trending themes, (ii) we discuss a characterization of the intersection between OI and crowdsourcing, identifying four dimensions (strategic, managerial, behavioral, and technological), (iii) we present a schematic reconceptualization of the thematic clusters, proposing an integrated view. We conclude by suggesting promising opportunities for future research.
On functorial (co)localization of algebras and modules over operads
Authors: Gutiérrez Javier J. , Röndigs Oliver , Spitzweck Markus , Østvær Paul Arne
Published: July 2021

Motivated by calculations of motivic homotopy groups, we give widely attained conditions under which operadic algebras and modules thereof are preserved under (co)localization functors.
Chronic Exposure to Hypoxia Inhibits Myelinogenesis and Causes Motor Coordination Deficits in Adult Mice
Authors: Chen Lin , Ren Shu-Yu , Li Rui-Xue , Liu Kun , Chen Jing-Fei , Yang Yu-Jian , Deng Yong-Bin , Wang Han-Zhi , Xiao Lan , Mei Feng , Wang Fei
Published: July 2021

Exposure to chronic hypoxia is considered to be a risk factor for deficits in brain function in adults, but the underlying mechanisms remain largely unknown. Since active myelinogenesis persists in the adult central nervous system, here we aimed to investigate the impact of chronic hypoxia on myelination and the related functional consequences in adult mice. Using a transgenic approach to label newly-generated myelin sheaths (NG2-CreERTM; Tau-mGFP), we found that myelinogenesis was highly active in most brain regions, such as the motor cortex and corpus callosum. After exposure to hypoxia (10% oxygen) 12 h per day for 4 weeks, myelinogenesis was largely inhibited in the 4-month old brain and the mice displayed motor coordination deficits revealed by the beam-walking test. To determine the relationship between the inhibited myelination and functional impairment, we induced oligodendroglia-specific deletion of the transcription factor Olig2 by tamoxifen (NG2-CreERTM; Tau-mGFP; Olig2 fl/fl) in adult mice to mimic the decreased myelinogenesis caused by hypoxia. The deletion of Olig2 inhibited myelinogenesis and consequently impaired motor coordination, suggesting that myelinogenesis is required for motor function in adult mice. To understand whether enhancing myelination could protect brain functions against hypoxia, we treated hypoxic mice with the myelination-enhancing drug-clemastine, which resulted in enhanced myelogenesis and improved motor coordination. Taken together, our data indicate that chronic hypoxia inhibits myelinogenesis and causes functional deficits in the brain and that enhancing myelinogenesis protects brain functions against hypoxia-related deficits.
Characterizing HIV discussions and engagement on Twitter
Authors: Malik Aqdas , Antonino Angi , Khan M Laeeq , Nieminen Marko
Published: July 2021

The novel settings provided by social media facilitate users to seek and share information on a wide array of subjects, including healthcare and wellness. Analyzing health-related opinions and discussions on these platforms complement traditional public health surveillance systems to support timely and effective interventions. This study aims to characterize the HIV-related conversations on Twitter by identifying the prevalent topics and the key events and actors involved in these discussions. Through Twitter API, we collected tweets containing the hashtag #HIV for a one-year period. After pre-processing the collected data, we conducted engagement analysis, temporal analysis, and topic modeling algorithm on the analytical sample (n = 122,807). Tweets by HIV/AIDS/LGBTQ activists and physicians received the highest level of engagement. An upsurge in tweet volume and engagement was observed during global and local events such as World Aids Day and HIV/AIDS awareness and testing days for trans-genders, blacks, women, and the aged population. Eight topics were identified that include “stigma”, “prevention”, “epidemic in the developing countries”, “World Aids Day”, “treatment”, “events”, “PrEP”, and “testing”. Social media discussions offer a nuanced understanding of public opinions, beliefs, and sentiments about numerous health-related issues. The current study reports various dimensions of HIV-related posts on Twitter. Based on the findings, public health agencies and pertinent entities need to proactively use Twitter and other social media by engaging the public through involving influencers. The undertaken methodological choices may be applied to further assess HIV discourse on other popular social media platforms.
Mindfulness Versus Cognitive Reappraisal: the Impact of Mindfulness-Based Stress Reduction (MBSR) on the Early and Late Brain Potential Markers of Emotion Regulation
Authors: Kaunhoven Rebekah Jane , Dorjee Dusana
Published: July 2021

Objectives

A positive association between trait mindfulness and cognitive reappraisal has previously been found. Using event-related potentials (ERPs), we investigated the impact of an 8-week MBSR course on early and late stages of emotion regulation using mindfulness and reappraisal.

Methods

Participants were allocated into an 8-week MBSR training group (n = 14 for task reports and self-reports; n = 10 for ERPs) or a wait-list control group (n = 15 for task reports and self-reports; n = 11 for ERPs). Pre and post the 8-week training, participants completed an affective picture viewing task and were instructed to regulate their responses to negative and neutral images using mindfulness, cognitive reappraisal and expressive suppression.

Results

At post-test, only the training group showed significant improvements in self-reported trait mindfulness and trait cognitive reappraisal, together with improvements in the self-reported ability to employ mindfulness and cognitive reappraisal during the task. The training group showed decreased 200–280 ms positivity across all three strategies at post-test. The LPP did not change over time but overall showed more positive mean amplitudes to cognitive appraisal.

Conclusions

These findings suggest that MBSR may adaptively modulate early attention deployment to emotional stimuli, but modulations of later stages of emotion processing may require more extensive mindfulness training. In addition, conscious employment of mindfulness may require less cognitive effort than cognitive reappraisal.