bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optical spectroscopy of blazars for the Cherenkov Telescope Array
Authors: Goldoni P. , Pita S. , Boisson C. , Max-Moerbeck W. , Kasai E. , Williams D. A. , D’Ammando F. , Navarro-Aranguiz V. , Backes M. , Barres de Almeida U. , Becerra-Gonzalez J. , Cotter G. , Hervet O. , Lenain J.-P. , Lindfors E. , Sol H. , Wagner S. 
Published: April 2021

Context. Blazars are the most numerous class of high-energy (HE; E ∼ 50 MeV−100 GeV) and very high-energy (VHE; E ∼ 100 GeV−10 TeV) gamma-ray emitters. Currently, a measured spectroscopic redshift is available for only about 50% of gamma-ray BL Lacertae objects (BL Lacs), mainly due to the difficulty in measuring reliable redshifts from their nearly featureless continuum-dominated optical spectra. The knowledge of the redshift is fundamental for understanding the emission from blazars, for population studies and also for indirect studies of the extragalactic background light and searches for Lorentz invariance violation and axion-like particles using blazars.
Aims. This paper is the first in a series of papers that aim to measure the redshift of a sample of blazars likely to be detected with the upcoming Cherenkov Telescope Array (CTA), a ground-based gamma-ray observatory.
Methods. Monte Carlo simulations were performed to select those hard spectrum gamma-ray blazars detected with the Fermi-LAT telescope still lacking redshift measurements, but likely to be detected by CTA in 30 hours of observing time or less. Optical observing campaigns involving deep imaging and spectroscopic observations were organised to efficiently constrain their redshifts. We performed deep medium- to high-resolution spectroscopy of 19 blazar optical counterparts with the Keck II, SALT, and ESO NTT telescopes. We searched systematically for spectral features and, when possible, we estimated the contribution of the host galaxy to the total flux.
Results. We measured eleven firm spectroscopic redshifts with values ranging from 0.1116 to 0.482, one tentative redshift, three redshift lower limits including one at z ≥ 0.449 and another at z ≥ 0.868. Four BL Lacs show featureless spectra.
Megaprojects—mega failures? The politics of aspiration and the transformation of rural Kenya
Authors: Müller-Mahn Detlef , Mkutu Kennedy , Kioko Eric 
Published: April 2021

AbstractMegaprojects are returning to play a key role in the transformation of rural Africa, despite controversies over their outcome. While some view them as promising tools for a ‘big push’ of modernization, others criticize their multiple adverse effects and risk of failure. Against this backdrop, the paper revisits earlier concepts that have explained megaproject failures by referring to problems of managerial complexity and the logics of state-led development. Taking recent examples from Kenya, the paper argues for a more differentiated approach, considering the symbolic role infrastructure megaprojects play in future-oriented development politics as objects of imagination, vision, and hope. We propose to explain the outcomes of megaprojects by focusing on the ‘politics of aspiration’, which unfold at the intersection between different actors and scales. The paper gives an overview of large infrastructure projects in Kenya and places them in the context of the country´s national development agenda ‘Vision 2030′. It identifies the relevant actors and investigates how controversial aspirations, interests and foreign influences play out on the ground. The paper concludes by describing megaproject development as future making, driven by the mobilizing power of the ‘politics of aspiration’. The analysis of megaprojects should consider not only material outcomes but also their symbolic dimension for desirable futures.
Ultra-low-vibration closed-cycle cryogenic surface-electrode ion trap apparatus
Authors: Dubielzig T. , Halama S. , Hahn H. , Zarantonello G. , Niemann M. , Bautista-Salvador A. , Ospelkaus C. 
Published: April 2021

We describe the design, commissioning, and operation of an ultra-low-vibration closed-cycle cryogenic ion trap apparatus. One hundred lines for low-frequency signals and eight microwave/radio frequency coaxial feed-lines offer the possibility of implementing a small-scale ion-trap quantum processor or simulator. With all supply cables attached, more than 1.3 W of cooling power at 5 K is still available for absorbing energy from electrical pulses introduced to control ions. The trap itself is isolated from vibrations induced by the cold head using a helium exchange gas interface. The performance of the vibration isolation system has been characterized using a Michelson interferometer, finding residual vibration amplitudes on the order of 10 nm rms. Trapping of 9Be+ ions has been demonstrated using a combination of laser ablation and photoionization.
Manifolds of isospectral arrow matrices
Authors: Ayzenberg A. A. , Buchstaber V. M. 
Published: April 2021

Abstract
An arrow matrix is a matrix with zeros outside the main diagonal, the first row and the first column. We consider the space

of Hermitian arrow

-matrices with fixed simple spectrum

. We prove that this space is a smooth

-manifold with a locally standard torus action: we describe the topology and combinatorics of its orbit space. If

, the orbit space

is not a polytope, hence

is not a quasitoric manifold. However, there is an action of a semidirect product

on

, and the orbit space of this action is a certain simple polytope

obtained from the cube by cutting off codimension-2 faces. In the case

, the space

is a solid torus with boundary subdivided into hexagons in a regular way. This description allows us to compute the cohomology ring and equivariant cohomology ring of the 6-dimensional manifold

and another manifold, its twin.
Bibliography: 32 titles.
Multivariate Haar systems in Besov function spaces
Authors: Oswald P. 
Published: April 2021

AbstractWe determine all cases for which the-dimensional Haar wavelet systemon the unit cubeis a conditional or unconditional Schauder basis in the classical isotropic Besov function spaces,,, defined in terms of first-order-moduli of smoothness. We obtain similar results for the tensor-product Haar system, and characterize the parameter range for which the dual ofis trivial for.Bibliography: 31 titles.
The preservation of threshold resonances and the splitting off of eigenvalues from the threshold of the continuous spectrum of quantum waveguides
Authors: Nazarov S. A. 
Published: April 2021

Abstract
Threshold resonance arises on the lower bound of the continuous spectrum of a quantum waveguide (the Dirichlet problem for the Laplace operator), provided that for this value of the spectral parameter a nontrivial bounded solution exists which is either a trapped wave decaying at infinity or an almost standing wave stabilizing at infinity. In many problems in asymptotic analysis, it is important to be able to distinguish which of the waves initiates the threshold resonance; in this work we discuss several ways to clarify its properties. In addition, we demonstrate how the threshold resonance can be preserved by fine tuning the profile of the waveguide wall, and we obtain asymptotic expressions for the near-threshold eigenvalues appearing in the discrete or continuous spectrum when the threshold resonance is destroyed.
Bibliography: 60 titles.
Characterization of solutions of strong-weak convex programming problems
Authors: Dudov S. I. , Osiptsev M. A. 
Published: April 2021

Abstract
Finite-dimensional problems of minimizing a strongly or weakly convex function on a strongly or weakly convex set are considered. Necessary and sufficient conditions for solutions of such problems are presented, which are based on estimates for the behaviour of the objective function on the feasible set taking account of the parameters of strong or weak convexity, as well as certain local features of the set and the function. The mathematical programming problem is considered separately for strongly and weakly convex functions. In addition, necessary conditions for a global and a local solution with differentiable objective function are found, in which a ‘strong’ stationarity condition is assumed to hold.
Bibliography: 33 titles.
A trace formula for higher order ordinary differential operators
Authors: Gal’kovskii E. D. , Nazarov A. I. 
Published: April 2021

Abstract
We obtain a first-order trace formula for a higher order differential operator on a closed interval in the case where the perturbation operator is the operator of multiplication by a finite complex-valued charge. For operators of even orders

, the result contains a term of new type, previously unknown.
Bibliography: 15 titles.
Recovery of integrable functions and trigonometric series
Authors: Plotnikov M. G. 
Published: April 2021

Abstract
Classes

of

-functions with fixed rate of decrease of their Fourier coefficients are considered. For each class

, it is shown that there exists a (recovery) set

with arbitrarily small measure such that any function in

can be recovered from its values on

. A formula for evaluation of the Fourier coefficients of such a function from its values on

is given. In addition, it is shown that, for any

-function, a function-specific recovery set can be found. The problem of recovery of general trigonometric series from the Zygmund classes which converge to summable functions on such sets

is also solved.
Bibliography: 10 titles.
Emergence of hierarchy in networked endorsement dynamics
Authors: Kawakatsu Mari , Chodrow Philip S. , Eikmeier Nicole , Larremore Daniel B. 
Published: April 2021

Significance
Hierarchies structure the lives of many social animals, including humans. We propose a generative model of time-varying networks in which endorsements between individuals give rise to enduring hierarchies. For several network-based ranking functions, our model possesses a distinct, analytically tractable, critical transition between egalitarian and hierarchical states. We also use our model to explore hierarchical structures in empirical data on hiring patterns among mathematicians, dominance relations among parakeets, and friendships among members of a fraternity, observing several persistent patterns. Overall, our model enables data-informed modeling of hierarchical networks in social and biological systems.
Brd4-bound enhancers drive cell-intrinsic sex differences in glioblastoma
Authors: Kfoury Najla , Qi Zongtai , Prager Briana C. , Wilkinson Michael N. , Broestl Lauren , Berrett Kristopher C. , Moudgil Arnav , Sankararaman Sumithra , Chen Xuhua , Gertz Jason , Rich Jeremy N. , Mitra Robi D. , Rubin Joshua B. 
Published: April 2021

Significance
Consistent sex differences in incidence and outcome have been reported in numerous cancers including brain tumors. GBM, the most common and aggressive primary brain tumor, occurs with higher incidence and shorter survival in males compared to females. Brd4 is essential for regulating transcriptome-wide gene expression and specifying cell identity, including that of GBM. We report that sex-biased Brd4 activity drives sex differences in GBM and renders male and female tumor cells differentially sensitive to BET inhibitors. The observed sex differences in BETi treatment strongly indicate that sex differences in disease biology translate into sex differences in therapeutic responses. This has critical implications for clinical use of BET inhibitors further affirming the importance of inclusion of sex as a biological variable.
De novo biosynthesis of a nonnatural cobalt porphyrin cofactor inE. coliand incorporation into hemoproteins
Authors: Perkins Lydia J. , Weaver Brian R. , Buller Andrew R. , Burstyn Judith N. 
Published: April 2021

SignificanceEnzymes rely on cofactors, both organic molecules and metal ions, for reactivity beyond what can be performed with the 20 standard amino acids. One way to expand the reactivity of heme-dependent proteins is to swap the native iron atom in the heme cofactor for a different metal. Because the resulting metal-containing cofactor is new to nature, methods for producing these nonnative hemoproteins are difficult and often limited to the test tube. Here, we report a method for subverting the heme biosynthetic pathway inE. colito produce cobalt protoporphyrin IX (CoPPIX) and CoPPIX-substituted hemoproteins in living cells. This method enables the use of CoPPIX-substituted enzymes as biocatalysts and widens the scope of proteins that may be studied by metal substitution.
Reduced phase stability and faster formation/dissociation kinetics in confined methane hydrate
Authors: Jin Dongliang , Coasne Benoit 
Published: April 2021

Significance
Large amounts of methane hydrate—which consists of water forming molecular ice cages around methane molecules—are trapped in the porosity of rocks and seafloors. The impact of this so-called “burning ice” on our environment remains unclear (methane is a potent greenhouse gas), especially the parameters driving its phase stability and kinetics. Here, using molecular modeling, we identify the mechanisms involved in the formation/dissociation of confined methane hydrate. The phase stability of confined methane hydrate is shown to be restricted to a narrower temperature/pressure range with faster underlying formation/dissociation kinetics. Such facilitated freezing, which helps rationalize experimental observations, is described using a mesoscale thermodynamic approach of the nucleation mechanism.
The role of annealing in determining the yielding behavior of glasses under cyclic shear deformation
Authors: Bhaumik Himangsu , Foffi Giuseppe , Sastry Srikanth 
Published: April 2021

Significance
Understanding the nature of the yielding transition in amorphous solids is of significant interest conceptually and for practical reasons. We use computer simulations of models of silica—a network glass—and an atomic glass to investigate the effect of annealing on yielding under cyclic shear deformation. We identify a threshold energy toward which poorly annealed glasses evolve as yielding is approached under cyclic deformation, and below which glasses display little change until they yield, with progressively stronger discontinuities as degree of annealing increases. The threshold energy thus separates two distinct regimes of yielding, with increasingly brittle behavior at lower energies. Interestingly, the threshold energy corresponds to well-studied dynamical cross-overs in the corresponding liquids.
An ultra-high-affinity small organic ligand of fibroblast activation protein for tumor-targeting applications
Authors: Millul Jacopo , Bassi Gabriele , Mock Jacqueline , Elsayed Abdullah , Pellegrino Christian , Zana Aureliano , Dakhel Plaza Sheila , Nadal Lisa , Gloger Andreas , Schmidt Eleonore , Biancofiore Ilaria , Donckele Etienne J. , Samain Florent , Neri Dario , Cazzamalli Samuele 
Published: April 2021

Significance
Fibroblast activation protein (FAP) has recently emerged as a tumor-associated antigen with abundant and selective expression in the majority of human solid malignancies. To the best of our knowledge, OncoFAP is the highest-affinity small organic FAP ligand reported to date, with a dissociation constant of 680 pM, as measured by fluorescence polarization. Upon intravenous administration, both fluorescent and radiolabeled OncoFAP derivatives exhibited a rapid and selective accumulation in FAP-positive tumors, sparing normal tissues. OncoFAP was also used as a modular component for the generation of therapeutic products, enabling the targeted delivery of a potent beta-emitter (lutetium-177), of fluorescein-specific chimeric antigen receptor (CAR) T cells or of highly cytotoxic auristatin derivatives to FAP-positive tumors in vitro and in vivo.
An Improved Partheno-Genetic Algorithm for Open Path Multi-Depot Multiple Traveling Salesmen Problem
Authors: Lou Ping , Xu Kun , Yan Junwei , Xiao Zheng 
Published: April 2021

Abstract
The Multiple traveling salesmen problem (MTSP) is a complex combinatorial optimization problem, which is an extension of the well-known traveling salesmen problem (TSP). Compared to TSP, MTSP is more suitable to model real-life problems. In this paper, an open path multi-depot multiple traveling salesmen problem (OPMDMTSP) is studied. For the problem studied, two different objectives are considered: minimizing the total cost of all sales staff and minimizing the longest travel length. For the OPMDMTSP, an improved partheno-genetic algorithm (IPGA) is proposed in this paper. In IPGA, a new selection operator that combining roulette selection and elitist selection is implemented. In addition, a more comprehensive mutation operation that introduces the propagation mechanism of invasive weed optimization algorithm is used. Extensive experiment that compares the proposed method with some state of the art methods shows that the IPGA is outperform other methods in terms of both solution quality and convergence ability.
Efficient Object Detection based on Deep Feature Fusion Network
Authors: Zhao Bo , Liu Shuyun , Liu Guizhong , Yang Zhonglin , Ma Zhiyang , Fu Huini 
Published: April 2021

Abstract
Real-time object detection is crucial for many applications, such as automatic driving, security monitoring. It is vital for these application to perform accurate detection while keeping real-time performance. This paper propose an efficient object detection method based on deep feature fusing strategy. The feature extraction network employs deep convolution neural network to fuse multi-channel input, including colored image, infrared image and motion image. Multiple sources of images can provide complementary information, which is beneficial to accurate object detection. The backbone network is based on darknet-53 while integrating with feature aggression modules to capture features of shallow and deep activation maps. Our network is first trained on large-scale IMAGENET and COCO datasets, and then fine-tuned on small-scale datasets collected in real world. A series of quantitatively and qualitatively experiments are conducted to show superiority and efficiency of our method.
Physical therapy scheduling of inpatients based on improved Genetic Algorithm
Authors: Li Xin , Chen Haibin 
Published: April 2021

Abstract
In recent years, the physical therapy has become more and more extensive. How to schedule corresponding treatments efficiently in rehabilitation hospitals has attracted the attention of many scholars. A typical physical therapy treatment can be divided into three stages, i.e., the beginning, the treating and the ending. Moreover, only the beginning and the ending stages require a therapist. The treating stage does not. In addition, a physical therapy treatment requires to occupy a bed and an instrument related simultaneously. In order to solve challenging scheduling problems, a genetic algorithm based on Waiting Time Priority Algorithm (WTPA) is designed. Finally, an instance from the rehabilitation department in a hospital is tested. By comparing with the classical simulated annealing algorithm (SA), it verifies the effectiveness and efficiency of the genetic algorithm designed.
Offline Handwritten Text Recognition Using Deep Learning: A Review
Authors: Wang Yintong , Xiao Wenjie , Li Shuo 
Published: April 2021

Abstract
The area of offline handwritten text recognition(OHTR) has been widely researched in the last decades, but it stills an important research problem. The OHTR system has an objective to transform a document image into text data. Compared with online handwriting recognition, the dynamic information about the writing trajectories in OHTR is not available. Many advancements have been proposed in the literature, most notably the application of deep learning methods to OHTR. In this paper, we introduced how this problem has been handled in the past few decades, analyze the latest advancements and the potential directions for future research in this field.
Weak atomic decompositions of B-valued weak Orlicz quasi-martingale spaces
Authors: Zhang Chuanzhou , Wang Jiufeng 
Published: April 2021

Abstract
In this paper, we define the B-valued weak Orlicz quasi-martingale spaces and three types of weak atoms. Three types of weak atomic decompositions of the weak Orlicz quasi-martingale spaces are proved by the geometric properties of Banach spaces.
Layout optimization of workshop equipment based on WITNESS
Authors: Wu Rongjie , Huang Zhonghua , Xie Ya 
Published: April 2021

Abstract
According to the production order, the engine parts workshop of a company mainly produces four parts: valve hydraulic tappet, camshaft, camshaft gear and bearing cover. With the increasing demand of production, the production capacity brought by the original workshop equipment layout gradually cannot meet the increasing demand. In this paper, based on the WITNESS simulation software, we are preparing to collect the data of engine parts and components production workshop in order to get the data information of each element by simulation, and reasoning the unreasonable parts where the busy rate is too high and put forward several improvement methods. Through WITNESS software simulation, respectively, we can analyse whether there will have improvement and conclude the optimal improvement project. As the busy rate of lathe group and milling machine group of the original workshop layout is more than 80%, while the statistics are less than 60% by using the optimal plan to improve the existing layout, reaching a reasonable busy rate. It can be concluded that it is feasible to solve the problem of high work step busy rate and improve the overall production efficiency of the workshop through reasonable equipment layout optimization.
Correlation analysis of College students’ achievement based on improved Apriori algorithm
Authors: Wang Hongqin 
Published: April 2021

Abstract
A large amount of student achievement information has been accumulated in the teaching information management system of colleges. It is of great significance to use data mining technology to analyze the data and find out the potential value of the data.The basic idea and defects of the Apriori algorithm are described in this paper, an improved Apriori algorithm is proposed,which is used to analyze the course scores of all students in the software engineering major of a university in 2018, and dig out the relationship between scores and courses, so as to provide learning guidance for students, provide teaching reference for teachers, and have certain guiding significance for the quality of talent cultivation in colleges and universities.
A deep learning method for classification of chest X-ray images
Authors: Zhao Jiashi , Li Mengmeng , Shi Weili , Miao Yu , Jiang Zhengang , Ji Bai 
Published: April 2021

Abstract
Deep learning techniques have provided new research methods for computer-aided diagnosis, allowing researchers to use deep learning methods to process medical imaging data. Chest X-ray examinations are widely used as a primary screening method for chest diseases. Therefore, it is of great importance to study diagnosis of 14 common pathologies in chest X-ray images using deep learning methods. In this paper, we propose a deep learning model named AM_DenseNet for chest X-ray image classification. The model adopts a dense connection network and adds an attention module after each dense block to optimize the model’s ability to extract features, and finally a Focal Loss function is applied to solve the data imbalance problem. The experiments used chest X-ray images as model input and were trained to output the probabilities of 14 chest pathologies. The Area under the ROC curve (AUC) was used to measure the classification results, and the final average AUC was 0.8537. The experimental results show that the AM_DenseNet model could complete the pathology classification of the chest X-ray images effectively.