bluuebunny/crossref_metadata_2025 huggingface dataset:
An experiment of relative velocity in a train using a smartphone
Authors: Priyanto Aan , Yusmantoro  , Aji Mahardika Prasetya
Published: December 2019

When we travel in a train moving at a certain velocity, we observe the stationary objects outside are moving backwards. These stationary objects seem to move due to a relative velocity. Consider that the stationary object outside the train is a man standing on the stationary floor watching a woman moving on a train. The woman on a train will see the man moving backward with similar velocity as her. In kinematics, this magnitude of relative velocity will always be the same whether the man is far away from or near the train, as long as he stands on the stationary floor.
Engagement and joy in the active learning classroom
Authors: Frank Brian W.
Published: December 2019

It is common when implementing active learning to have concerns about whether students will meaningfully engage in planned activities and discussions.­ Within the physics education community, we are fortunate to have access to a collection of best practices on promoting student engagement and fostering a productive classroom climate. Written for the physics teacher audience specifically, this collection includes a variety of useful tips and resources that are directly applicable to a variety of physics classrooms and are freely available at www.physport.org. In this column, I hope to contribute to this broad conversation about promoting students’ productive engagement in a different manner by sharing a few pitfalls that I fell into during my first few years of physics teaching—pitfalls that created barriers to students experiencing joy as a central and defining feature of their active learning experiences. Some of the challenges I faced in creating a more joyful active learning classroom were related to tacit beliefs I held about active learning that were at times counterproductive, including notions that
Electric field lines of relativistically moving point charges
Authors: Ruhlandt Daja , Mühle Steffen , Enderlein Jörg
Published: December 2019

Generation of electromagnetic fields by moving charges is a fascinating topic where the tight connection between classical electrodynamics and special relativity becomes particularly apparent. One can gain direct insight into the fascinating structure of such fields by visualizing the electric field lines. However, the calculation of electric field lines for arbitrarily moving charges is far from trivial. Here, we derive an equation for the direction that points from the retarded position of a moving charge towards a specific field line position, which allows for a simple construction of these lines. We analytically solve this equation for several special but important cases: for an arbitrary rectilinear motion, for the motion within the wiggler magnetic field of a free electron laser, and for the motion in a synchrotron.
Analysis of aperiodicity in artistic Noh singing voice using an impulse sequence representation of excitation source
Authors: Kadiri Sudarsana Reddy , Yegnanarayana B.
Published: December 2019

Aperiodicity in the voice source is caused by changes in the vocal fold vibrations, other than the normal quasi-periodicity and the turbulence at the glottis. The aperiodicity appears to be one of the main properties that is responsible for conveying the emotion in artistic voices. In this paper, the feasibility of representing the excitation source characteristics in artistic (Noh) singing voice by an impulse-like sequence in the time domain is examined. The impulses at the glottal closure instants contribute to the major excitation of the vocal tract system. The sequence of such impulses produces harmonics of the fundamental frequency in the spectrum. The amplitude variation or amplitude modulation (AM) of these impulses in the sequence contributes to the aperiodicity in the excitation, and can result in appearance of subharmonics in the spectrum. The variation in the impulse intervals or frequency modulation (FM) can also contribute to the aperiodicity in the excitation. The aperiodic component of the excitation in the Noh voice is examined in the impulse-like sequence derived from the signal using the single frequency filtering analysis. The effects of aperiodicity are explained for synthetic AM and FM sequences of impulses using spectrograms and saliency plots.
Understanding the Inclusiveness of Integrated Physical Education From the Perspectives of Adults With Visual Impairments
Authors: Haegele Justin A. , Hodge Samuel R. , Zhu Xihe , Holland Steven K. , Wilson Wesley J.
Published: December 2019

The purpose of this study was to examine the perspectives of individuals with visual impairment toward inclusion and the inclusiveness of their integrated physical education experiences. A retrospective, qualitative-description research approach was used, and 10 adults (age 20–35 years) with visual impairments acted as the participants. The data sources included one-on-one telephone interviews and reflective interview notes. A theoretical thematic analysis approach was used to analyze the data. Three interrelated themes were identified: “I always felt like a misfit”: a missing sense of belonging, acceptance, and value; “I felt very excluded, very pushed to the side”: lack of access to activity participation; and “Even though it sucked, I do agree with it”: preference for integrated settings. Collectively, the participants recalled that experiencing feelings of inclusion during physical education were rare. Despite this, they expressed a perceived importance of being integrated in contexts with their peers.
The Slippery Slope: Can Motivation and Perfectionism Lead to Burnout in Coaches?
Authors: Vealey Robin S. , Martin Eric , Coppola Angela , Ward Rose Marie , Chamberlin Jacob
Published: December 2019

The purpose of the study was to investigate the relationships between perfectionism, motivation, burnout, and coaching satisfaction in high school and collegiate coaches (n = 311). Coaches completed the modified Maslach Burnout Inventory, the Behavioral Regulation in Sport Questionnaire, the Multidimensional Perfectionism Scale, and an investigator-designed survey to assess satisfaction. As predicted, perfectionism was related to both motivation and burnout. In particular, socially-prescribed perfectionism emerged as the most significant type of perfectionism, showing positive relationships with controlled forms of motivation and burnout and negative relationships with autonomous forms of motivation and feelings of personal accomplishment. Self-oriented perfectionism was related to motivation, but not directly related to burnout, and other-oriented perfectionism was not significantly related to motivation or burnout. Autonomous motivation was strongly associated with coaches’ satisfaction. The influence of socially-prescribed perfectionism on coaches is discussed in relation to the high expectations placed on coaches by programs and communities, perhaps contributing to feelings of low autonomy and external regulation. Controlling forms of social expectations and external regulation may act as a “slippery slope” in which the initial motivation of coaches may move toward burnout.
Clinically Relevant Campylobacter jejuni Subtypes Are Readily Found and Transmitted within the Cattle Production Continuum but Present a Limited Foodborne Risk
Authors: Inglis G. Douglas , Gusse Jenny F. , House Kathaleen E. , Shelton Tara G. , Taboada Eduardo N.
Published: December 2019

Limited information is available on the transmission of
Campylobacter jejuni
subtypes in the beef production continuum and the foodborne risk posed to humans. Cattle were colonized by diverse subtypes of
C. jejuni
, and the densities of the bacterium shed in feces increased during the confined feeding period.
Campylobacter jejuni
was readily associated with the digesta, feces, and hides of cattle entering the abattoir, as well as the local environment. Moreover,
C. jejuni
cells were deposited on carcasses via direct contact and aerosols, but the bacterium was not detected in the ground beef generated from contaminated carcasses. We conclude that
C. jejuni
bacterial cells associated with beef cattle do not represent a significant risk through food consumption and suggest that clinically relevant subtypes are transmitted through alternate routes of exposure.
Faecal volatile organic compounds in preterm babies at risk of necrotising enterocolitis: the DOVE study
Authors: Probert Chris , Greenwood Rosemary , Mayor Arno , Hughes David , Aggio Raphael , Jackson Rachel Elizabeth , Simcox Liz , Barrow Heather , García-Finana Marta , Ewer Andrew K
Published: December 2019

Background

Early diagnosis of necrotising enterocolitis (NEC) may improve prognosis but there are no proven biomarkers.

Objective

To investigate changes in faecal volatile organic compounds (VOCs) as potential biomarkers for NEC.

Design

Multicentre prospective study.

Settings

8 UK neonatal units.

Patients

Preterm infants <34 weeks gestation.

Methods

Daily faecal samples were collected prospectively from 1326 babies of whom 49 subsequently developed definite NEC. Faecal samples from 32 NEC cases were compared with samples from frequency-matched controls without NEC. Headspace, solid phase microextraction gas chromatography/mass spectrometry was performed and VOCs identified from reference libraries. VOC samples from cases and controls were compared using both discriminant and factor analysis methods.

Results

VOCs were found to cluster into nine groups (factors), three were associated with NEC and indicated the possibility of disease up to 3–4 days before the clinical diagnosis was established. For one factor, a 1 SD increase increased the odds of developing NEC by 1.6 times; a similar decrease of the two other factors was associated with a reduced risk (OR 0.5 or 0.7, respectively). Discriminant analyses identified five individual VOCs, which are associated with NEC in babies at risk, each with an area under the receiver operating characteristics curve of 0.75–0.76, up to 4 days before the clinical diagnosis was made.

Conclusions

Faecal VOCs are altered in preterm infants with NEC. These data are currently insufficient to enable reliable cotside detection of babies at risk of developing NEC and further work is needed investigate the role of VOCs in clarifying the aetiology of NEC.
Concordance of chronic conditions among the household members in Shanghai: a cross-sectional study
Authors: Qin Yingyi , Guo Yibin , Tang Yuanjun , Wu Cheng , Zhang Xinji , He Qian , He Jia
Published: December 2019

Objectives

Members living in the same household tend to share some similar behaviours and environment. We want to quantitatively assess the associations of chronic conditions to investigate the concordance of disease status among the household members.

Setting

Shanghai, China.

Participants

Our data were from the fifth Health Service Survey in Shanghai in 2013. 12 002 households with 31 531 residents were selected in this survey by using a three-stage, stratified, random sampling method.

Outcome measures

Five highly prevalent chronic conditions, namely hypertension, diabetes, ischaemic heart disease (IHD), cerebrovascular disease (CVD) and obesity were chosen. The generalised estimating equations (GEE) model was used to estimate the associations adjusted for age, gender, education status, health insurance status, smoking and drinking. Using a subsample of adult children with parents’ chronic conditions as the key risk factor and a subsample of wives with the chronic conditions of the husband as key risk factor, we reran our GEE models to explore chronic condition concordance within these relationships.

Results

A total of 10 198 households with 27 010 adult participants were included. Using all adult household members, we found positive statistically significant associations between one’s chronic conditions and the same disease status of their household members (hypertension (OR=3.26, 95% CI 3.02 to 3.52); diabetes (OR=1.68, 95% CI 1.40 to 2.01); IHD (OR=5.31, 95% CI 3.56 to 7.92); CVD (OR=3.40, 95% CI 1.99 to 5.80); obesity (OR=3.41, 95% CI 2.34 to 4.96)). The results of analysing ad-child subsample and spouse subsample also showed similar associations. Moreover, the potential concordance of different chronic conditions was found between hypertension and diabetes.

Conclusions

We found chronic condition concordance within households. This study provides evidence that the chronic conditions of other members of a household may be a significant risk factor for a household member’s own health.
The 20 m shuttle run is not a valid test of cardiorespiratory fitness in boys aged 11–14 years
Authors: Welsman Jo , Armstrong Neil
Published: December 2019

Objectives

The 20 m shuttle run test (20mSRT) is used to estimate cardiorespiratory fitness (CRF) through the prediction of peak oxygen uptake (V˙O2), but its validity as a measure of CRF during childhood and adolescence is questionable. This study examined the validity of the 20mSRT to predict peakV˙O2.

Methods

PeakV˙O2was measured during treadmill running. Log-linear regression was used to correct peakV˙O2for body mass and sum of skinfolds plus age. Boys completed the 20mSRT under standardised conditions. Maximum speed (km/h) was used with age to predict peakV˙O2using the equation developed by Légeret al. Validity was examined from linear regression methods and limits of agreement (LoA). Relationships between 20mSRT performance and allometrically adjusted peakV˙O2, and predicted per cent fat were examined.

Results

The sample comprised 76 boys aged 11–14 years. Predicted and measured mass-related peakV˙O2(mL/kg/min) shared common variance of 32%. LoA revealed that measured peakV˙O2ranged from 15% below to 25% above predicted peakV˙O2. There were no significant relationships (p>0.05) between predicted peakV˙O2and measured peakV˙O2adjusted for mass, age and skinfold thicknesses. Adjusted for body mass and age, peakV˙O2was not significantly related (p>0.05) to 20mSRT final speed but a weak, statistically significant (r=0.24, p<0.05) relationship was found with peakV˙O2adjusted for mass and fatness. Predicted per cent fat was negatively correlated with 20mSRT speed (r=−0.61, p<0.001).

Conclusions

The 20mSRT reflects fatness rather than CRF and has poor validity grounded in its flawed estimation and interpretation of peakV˙O2in mL/kg/min.
Regional spreading of symptoms at diagnosis as a prognostic marker in amyotrophic lateral sclerosis: a population-based study
Authors: Manera Umberto , Calvo Andrea , Daviddi Margherita , Canosa Antonio , Vasta Rosario , Torrieri Maria Claudia , Grassano Maurizio , Brunetti Maura , D'Alfonso Sandra , Corrado Lucia , De Marchi Fabiola , Moglia Cristina , D'Ovidio Fabrizio , Mora Gabriele , Mazzini Letizia , Chiò Adriano
Published: December 2019

Objective

The lack of prognostic biomarkers in patients with amyotrophic lateral sclerosis (ALS) induced researchers to develop clinical evaluation tools for stratification and survival prediction. We assessed the correlation between patterns of functional involvement, considered as a cumulative number of body regions involved, and overall survival in a population-based series of patients with ALS (PARALS).

Methods

We derived the functional involvement of four body regions at diagnosis using ALSFRS-R subscores for bulbar, upper limbs, lower limbs and respiratory/thoracic regions. We analysed the effect of number of body regions involved (NBRI) at diagnosis on overall survival, adjusting for age at onset, sex, site of onset, diagnostic delay, forced vital capacity, body mass index, mutational status, cognition and comparing it with King’s staging system.

Results

The NBRI was strongly related to survival, with a progressive increase of death/tracheostomy risk among groups (two body regions HR=1.24, 95% CI 1.06 to 1.45, p=0007; three body regions HR=1.65, 95% CI 1.38 to 1.98, p<0.001; four body regions HR=2.68, 95% CI 2.11 to 3.39, p<0.001). Using ALSFRS-R score, the consistency between the number of regions involved and King’s clinical stage at diagnosis was very high (81%). The evaluation of respiratory/thoracic region and cognition allowed to subdivide patients into different prognostic categories. Regional spreading of the disease is associated with survival, independently from the initial region involved.

Conclusions

The evaluation of NBRI, with the inclusion of initial respiratory/thoracic involvement and cognition, can be useful in many research fields, improving the stratification of patients. Our findings highlight the importance of the spatial spreading of functional impairment in the prediction of ALS outcome.
Aneurysm wall cellularity affects healing after coil embolization: assessment in a rat saccular aneurysm model
Authors: Nevzati Edin , Rey Jeannine , Coluccia Daniel , Grüter Basil Erwin , Wanderer Stefan , vonGunten Michael , Remonda Luca , Frosen Juhana , Widmer Hans Rudolf , Fandino Javier , Marbacher Serge
Published: December 2019

Background and purpose

Despite significant technical advances, recanalization rates after endovascular therapy of ruptured intracranial aneurysms (IAs) remain a clinical challenge. A histopathological hallmark of ruptured human IA walls is mural cell loss. Mural smooth muscle cells (SMCs) are known to promote intraluminal healing in thrombosed experimental aneurysms. In this rat model we assess the natural history and healing process after coil embolization in SMC-rich and decellularized aneurysms.

Methods

Saccular aneurysms were created by end-to-side anastomosis of an arterial graft from the descending thoracic aorta of a syngeneic donor rat to the infrarenal abdominal aorta of recipient male Wistar rats. Untreated arterial grafts were immediately transplanted, whereas aneurysms with loss of mural cells were chemically decellularized before implantation. Aneurysms underwent coil implantation during aneurysm anastomosis. Animals were randomly assigned either to the non-decellularized or decellularized group and underwent macroscopic and histological analyses on days 3, 7, 21, or 90 post-coil implantation.

Results

A total of 55 rats underwent macroscopic and histologic analysis. After coil embolization, aneurysms with SMC-rich walls showed a linear course of thrombosis and neointima formation whereas decellularized aneurysms showed marked inflammatory wall degeneration with increased recanalization rates 21 days (p=0.002) and 90 days (p=0.037) later. The SMCs showed the ability to actively migrate into the intra-aneurysmal thrombus and participate in thrombus organization.

Conclusions

Coil embolization of aneurysms with highly degenerated walls is prone to further wall degeneration, increased inflammation, and recanalization compared with aneurysms with vital SMC-rich walls.
Drain in laparoscopic cholecystectomy in acute calculous cholecystitis: a randomised controlled study
Authors: Valappil Mithun V , Gulati Sumit , Chhabra Manish , Mandal Ajay , De Bakshi Sanjay , Bhattacharyya Avik , Ghatak Supriyo
Published: December 2019

Background

There is paucity of evidence regarding the role of drain in laparoscopic cholecystectomy (LC) in acute calculous cholecystitis (ACC), and surgeons have placed the drains based on their experiences, not on evidence-based guidelines. This study aims to assess the value of drain in LC for ACC in a randomised controlled prospective study.

Patients and methods

All patients with mild and moderate ACC undergoing LC were assessed. Preoperatively, patients with choledocholithiasis, Mirizzi syndrome and biliary stent were excluded. Intraoperatively or postoperatively, patients with complications, partial cholecystectomies and malignancies were excluded. Patients were randomised using computer-generated random numbers into two groups at the end of cholecystectomy before closure. Requirement of radiologically guided (ultrasonography () or CT) percutaneous aspiration/drainage of symptomatic intra-abdominal collection or reoperation; continuation of parenteral antibiotics beyond 24 hours or change in antibiotics empirically or based on peritoneal fluid culture sensitivity; requirement of postoperative USG or CT scan based on postoperative clinical course; wound infection rates; postoperative pain using numeric rating scale at 6 and 24 hours; and the duration of hospital stay in both groups were noted.

Results

Forty-two out of 50 consecutive patients were randomised into two equal groups. Pain score at 6 and 24 hours was less in patients without drain. All other complication rates and duration of stay were similar in both groups.

Conclusions

Drains should not be placed routinely after LC in ACC as it increases pain and does not help in detecting or decreasing complications.
The small quantum cohomology of the Cayley Grassmannian
Authors: Benedetti Vladimiro , Manivel Laurent
Published: December 2019

We compute the small cohomology ring of the Cayley Grassmannian, that parametrizes four-dimensional subalgebras of the complexified octonions. We show that all the Gromov–Witten invariants in the multiplication table of the Schubert classes are nonnegative and deduce Golyshev’s conjecture [Formula: see text] holds true for this variety. We also check that the quantum cohomology is semisimple and that there exists, as predicted by Dubrovin’s conjecture, an exceptional collection of maximal length in the derived category.
A comparative study between the modified Fritzsch and nearest neighbor interaction textures
Authors: García-Aguilar J. D. , Gómez-Izquierdo Juan Carlos
Published: December 2019

From the mass textures’ point of view, we present a comparative study of the [Formula: see text] flavor symmetry in the left–right symmetry model (LRSM) and the baryon minus lepton model (BLM) taking into account their predictions on the CKM mixing matrix. To do this, we recover the already studied quark mass matrix, that comes from some published papers, and under certain strong assumptions, one can show that there are predictive scenarios in the LRSM and BLM where the modified Fritzsch and nearest neighbor interaction (NNI) textures drive, respectively, the quark mixings. As the main result, the CKM mixing matrix is in good agreement with the last experimental data in the flavored BLM model.
On an electron in a nonuniform axial magnetic field in a uniformly rotating frame
Authors: Bakke K. , Ribeiro R. F. , Salvador C.
Published: December 2019

The interaction of an electron with a nonuniform axial magnetic field is analyzed in a uniformly rotating frame. In particular, the magnetic field is proportional to the square of the radial distance from the symmetry axis. Then, in search of analytical solutions to the Schrödinger equation, it is shown that these solutions are possible if the nonuniform magnetic field possesses a discrete set of values.
Improved priority-based data aggregation congestion control protocol
Authors: Singh Prabhdeep , Gupta Anuj Kumar , Singh Ravinder
Published: December 2019

With advancement in multimedia applications, Wireless sensor networks (WSNs) are becoming popular due to their inherent characteristics and wide range of applications. However, WSNs contain very small sensor nodes, these nodes are battery constrained. Also, the batteries of these sensor nodes are not either replaceable or rechargeable. Therefore, many energy efficient protocols have been implemented so far to improve the network lifetime. However, the data aggregation at sink may suffer from data flooding issue, which reduces the network lifetime of WSNs. For handling this issue, in this paper, an effective data aggregation approach is designed. We have designed a priority-based data aggregation control protocol, which considers token bucket, Lempel–Ziv–Welch (LZW) compression and a hybrid of ant colony optimization and particle swarm optimization-based soft computing approach. Extensive experiments reveal that the presented protocol provides better network lifetime in contrast to the existing energy efficient protocols.
Sol–gel derived SiO2–B2O3–Na2O–ZnO–Al2O3 glass powder for glass-based composite
Authors: Wen Changxiu , Cui Xiaoxia , Xu Yantao , Yang Pengxiang , Wang Xiaozhang , Zhang Hui , Zhang Yang , Lu Min , Guo Haitao
Published: December 2019

The glass powder with a relatively complicated composition of 64.02SiO2–10.05B2O3–7.84Na2O–14.07ZnO–4.02Al2O3 (in wt.%) was first synthesized via sol–gel route. The optimal synthesis conditions for the amorphous gel are obtained. The glass transition temperature [Formula: see text] of xerogel was detected as 552[Formula: see text]C and the glass network structure formed by the [SiO4], [BO4] and [AlO4] units were confirmed by the Fourier Transform-Infrared Spectroscopy (FT-IR). The phase structure and morphologies of glass powder were characterized by X-ray diffractometer (XRD) and Field Emission-Scanning Electron Microscope (FE-SEM), the xerogels and sol–gel glasses exhibit amorphous phase when the heat-treatment temperature increases from [Formula: see text]C to [Formula: see text]C. The prepared glass powder with high specific surface areas and a large amount of pores contribute to the synthesis of a composite of glass-mullite-[Formula: see text]-eucryptite at a relatively low sintering temperature of [Formula: see text]C, which present a relatively low coefficient of thermal expansion (CTE) and high mechanical strength.
Simulation and experiment of X-ray communication in re-entry dusty plasma region
Authors: Li Yao , Su Tong , Sheng Lizhi , Xu Neng , Zhao Baosheng
Published: December 2019

Compared with the other wireless communication band, X-ray carrier has the merits of lower wavelength, higher frequency and photon energy, which could provide a novel method to solve the communication problems of re-entry blackout region. In this paper, transmission characteristics of X-ray carrier in the re-entry dusty plasma medium were analyzed first, simulation results indicate that dusty particles were more likely to impede the microwave signal than X-ray carrier. Then an alkali metal plasma source was designed to simulate the re-entry dusty plasma sheath for simplification. Transmission co-efficiency under different X-ray energy were tested, which pointed out that X-ray signal would obtain more than 79.4% transmission co-efficiency on condition of dynamic and dusty plasma medium. Finally, we give our proposal and potential capability of X-ray communication in the re-entry plasma condition.
A proton-implanted planar waveguide fabricated in terbium gallium garnet crystal
Authors: Wang Yue , Long Xue-Wen , Zhu Qi-Feng , Chen Jing-Yi , Xu Jun , Liu Chun-Xiao
Published: December 2019

The investigation on the terbium gallium garnet (TGG) crystal waveguides in the visible and near-infrared bands is significant for potential applications in science and technology. In this work, we report on a TGG planar waveguide based on the proton irradiation with an energy of 400 keV and a dose of [Formula: see text] ions/cm2. The annealing treatments are adopted to improve optical performances of the waveguide on the conditions of 260[Formula: see text]C and 410[Formula: see text]C severally for 1 h. The dark-mode spectra and the refractive index distributions of the TGG waveguide are obtained before and after the thermal treatments. There is a strange phenomenon that nine modes are observed on the m-line curve after the annealing treatment at 410[Formula: see text]C. The theoretical and experimental results demonstrate that the fabricated waveguide annealed at the temperature of 410[Formula: see text]C can propagate more guided modes and have better capacity to confine light.
The enhanced measurement-device-independent quantum key distribution with heralded pair coherent state
Authors: He Yefeng , Ma Wenping
Published: December 2019

With heralded pair coherent states (HPCS), orbital angular momentum (OAM) states and pulse position modulation (PPM) technology, a decoy-state measurement-device-independent quantum key distribution (MDI-QKD) protocol is proposed. OAM states and PPM technology are used to realize the coding of the signal states in the HPCS light source. The use of HPCS light source, OAM coding and PPM coding cannot only reduce the error rate but also improve the key generation rate and communication distance. The new MDI-QKD protocol also employs three-intensity decoy states to avoid the attacks against the light source. By calculating the error rate and key generation rate, the performance of the MDI-QKD protocol is analyzed. Numerical simulation shows that the protocol has very low error rate and very high key generation rate. Moreover, the maximum communication distance can reach 455 km.
General Method to Design Reversible Universal n-Bit Up/Down Counters
Authors: Kalantari Zeinab , Eshghi Mohammad , Mohammadi Majid , Jassbi Somayeh
Published: December 2019

With the growing trend towards reducing the size of electronic devices, reducing power consumption has become one of the major concerns of circuit designers, and designing reversible circuits is one of the approaches proposed for reducing power consumption. Although several studies have been done in the field of synthesizing combinational reversible circuits, little work has been done for designing reversible sequential circuits. Furthermore, many researches in this context use traditional designs which replace latches, flip-flops and associated combinational gates with their reversible counterparts. This traditional technique is not very promising, because it leads to high quantum cost (QC) and garbage outputs. Recently, researchers have proposed direct design of reversible sequential circuits using Reed Muller expressions to obtain next state output. Since most sequential circuits have multiple outputs, using common product terms between multiple outputs might decrease QC significantly.

In this paper, a modular and low QC design for a synchronous reversible [Formula: see text]-bit up/down counter with parallel load capability is presented. In this design, the common terms among multiple outputs are used efficiently, which leads to a low QC for the counter. A general formula to evaluate the QC of our proposed reversible counter is presented. This result shows that in our proposed design by increasing the number of bits of counter ([Formula: see text], the QC increases linearly, while in previous works by increasing the number of bits of counter, the QC increases exponentially.
Approximation Algorithm for the Broadcast Time in k-Path Graph
Authors: BHABAK PUSPAL , HARUTYUNYAN HOVHANNES A.
Published: December 2019

Broadcasting is an information dissemination problem in a connected network in which one node, called the originator, must distribute a message to all other nodes by placing a series of calls along the communication lines of the network. In every unit of time, the informed nodes aid the originator in distributing the message. Finding the broadcast time of any vertex in an arbitrary graph is NP-complete. The polynomial time solvability is shown only for certain graphs like trees, unicyclic graphs, tree of cycles, necklace graphs, fully connected trees and tree of cliques. In this paper we study the broadcast problem in k-path graphs. For any originator of the k-path graph we present a (4 – ϵ)-approximation algorithm in the worst case. The algorithm gives a better approximation ratio for some large classes of k-path graphs. Moreover, our algorithm generates the optimal broadcast time for some cases.
Traversal with Enumeration of Geometric Graphs in Bounded Space
Authors: KHAKABIMAMAGHANI SAHAND , MASJOODY MASOOD , STACHO LADISLAV
Published: December 2019

In this paper, we provide an algorithm for traversing geometric graphs which visits all vertices and reports every vertex and edge exactly once. To achieve this, we combine a given geometric graph G with the integer lattice, seen as a graph, in such a way that the resulting hypothetical graph can be traversed using a known algorithm which is based on face routing. To overcome the problem with hypothetical vertices and edges, we develop an algorithm for visiting any k-th neighborhood of a vertex in a graph straight-line drawn in the plane using O(k log k) memory. The memory needed to complete the traversal of a geometric graph then turns out to depend on the maximum graph distance among pairs of distinct vertices of G whose Euclidean distance is greater than one and less than [Formula: see text].
Deep ReLU networks and high-order finite element methods
Authors: Opschoor Joost A. A. , Petersen Philipp C. , Schwab Christoph
Published: December 2019

Approximation rate bounds for emulations of real-valued functions on intervals by deep neural networks (DNNs) are established. The approximation results are given for DNNs based on ReLU activation functions. The approximation error is measured with respect to Sobolev norms. It is shown that ReLU DNNs allow for essentially the same approximation rates as nonlinear, variable-order, free-knot (or so-called “[Formula: see text]-adaptive”) spline approximations and spectral approximations, for a wide range of Sobolev and Besov spaces. In particular, exponential convergence rates in terms of the DNN size for univariate, piecewise Gevrey functions with point singularities are established. Combined with recent results on ReLU DNN approximation of rational, oscillatory, and high-dimensional functions, this corroborates that continuous, piecewise affine ReLU DNNs afford algebraic and exponential convergence rate bounds which are comparable to “best in class” schemes for several important function classes of high and infinite smoothness. Using composition of DNNs, we also prove that radial-like functions obtained as compositions of the above with the Euclidean norm and, possibly, anisotropic affine changes of co-ordinates can be emulated at exponential rate in terms of the DNN size and depth without the curse of dimensionality.
Text Summarisation Using Laplacian Centrality-Based Minimum Vertex Cover
Authors: Gupta Anand , Kaur Manpreet
Published: December 2019

Outdegree Centrality (OC) is a graph-based centrality measure that captures local connectedness of a node in a graph. The measure has been used in the literature to highlight key sentences in a graph-based optimisation method for summarisation. It is observed in resultant summaries that OC tends to be biased towards selecting introductory sentences of the document producing only generic summaries. The different graph centrality measures lead to different interpretations of a summary. Therefore, the authors propose to use another suitable centrality measure in order to generate more specific summary rather than a generic summary. Such a summary is expected to be highly informative covering all the subtopics of the source document. This requirement has instigated the authors to use Laplacian Centrality (LC) measure to find the significance of the nodes. The essence of this measure lies in highlighting central nodes from subgraphs which contribute non-uniformly towards the common goal of the graph. The modified method has shown significant improvement in informativeness and coherence of summaries and outperformed state-of-the-art results.
Curvature properties of Nariai spacetimes
Authors: Shaikh Absos Ali , Ali Akram , Alkhaldi Ali H. , Chakraborty Dhyanesh
Published: December 2019

This paper is concerned with the study of the geometry of (charged) Nariai spacetime, a topological product spacetime, by means of covariant derivative(s) of its various curvature tensors. It is found that on this spacetime the condition [Formula: see text] is satisfied and it also admits the pseudosymmetric type curvature conditions [Formula: see text] and [Formula: see text]. Moreover, it is 4-dimensional Roter type, [Formula: see text]-quasi-Einstein and generalized quasi-Einstein spacetime. The energy–momentum tensor is expressed explicitly by some 1-forms. It is worthy to see that a generalization of such topological product spacetime proposes to exist with a class of generalized recurrent type manifolds which is semisymmetric. It is observed that the rank of [Formula: see text], [Formula: see text], of Nariai spacetime (NS) is 0 whereas in case of charged Nariai spacetime (CNS) it is 2, which exhibits that effects of charge increase the rank of Ricci tensor. Also, due to the presence of charge in CNS, it gives rise to the proper pseudosymmetric type geometric structures.
Short- and long-term movement of mudflows of the Mississippi River Delta Front and their known and potential impacts on oil and gas infrastructure
Authors: Chaytor Jason D. , Baldwin Wayne E. , Bentley Samuel J. , Damour Melanie , Jones Douglas , Maloney Jillian , Miner Michael D. , Obelcz Jeff , Xu Kehui
Published: December 2019

Mudflows on the Mississippi River Delta Front (MRDF) are recognized hazards to oil and gas infrastructure in the shallow (20–300 m water depth) Gulf of Mexico. Preconditioning of the seafloor for failure results from high sedimentation rates coupled with slope over-steepening, under-consolidation and abundant biogenic gas production. Catastrophic failure of production platforms and pipelines due to seafloor displacement during infrequent large hurricanes such as Camille in 1969 and Ivan in 2004, point to cyclical loading of the seafloor by waves as a primary movement trigger. Due to data limitations, the role of smaller storms and background oceanographic processes in driving seafloor movement has remained largely unconstrained but these are thought to contribute to significant seafloor change. With the aid of new high-resolution multibeam mapping and seismic reflection profiling across sections of the MRDF, several moving features within the deforming delta-front environment are investigated and potential hazards to infrastructure installed and adjacent to the region are discussed. Via repeat mapping surveys of selected areas and records of changing shipwreck locations, we highlight significant seafloor displacement across annual to decadal timescales. For example, individual blocks mapped within mudflow gullies adjacent to Southwest Pass show downslope transport of more than 80 m in a single year, while the SS
Virginia
, a 153 m-long oil tanker sunk in 1942, has been relocated and found to have moved downslope more than 400 m in 14 years, without a major hurricane (>Category 2) passing through the region.
RAiSD-X
Authors: Alachiotis Nikolaos , Vatsolakis Charalampos , Chrysos Grigorios , Pnevmatikatos Dionisios
Published: December 2019

Detecting traces of positive selection in genomes carries theoretical significance and has practical applications from shedding light on the forces that drive adaptive evolution to the design of more effective drug treatments. The size of genomic datasets currently grows at an unprecedented pace, fueled by continuous advances in DNA sequencing technologies, leading to ever-increasing compute and memory requirements for meaningful genomic analyses. The majority of existing methods for positive selection detection either are not designed to handle whole genomes or scale poorly with the sample size; they inevitably resort to a runtime versus accuracy tradeoff, raising an alarming concern for the feasibility of future large-scale scans. To this end, we present RAiSD-X, a high-performance system that relies on a decoupled access-execute processing paradigm for efficient FPGA acceleration and couples a novel, to our knowledge, sliding-window algorithm for the recently introduced μ statistic with a mutation-driven hashing technique to rapidly detect patterns in the data. RAiSD-X achieves up to three orders of magnitude faster processing than widely used software implementations, and more importantly, it can exhaustively scan thousands of human chromosomes in minutes, yielding a scalable full-system solution for future studies of positive selection in species of flora and fauna.
Undecidability of

d
<:

and its decidable fragments
Authors: Hu Jason Z. S. , Lhoták Ondřej
Published: December 2019

Dependent Object Types (DOT) is a calculus with path dependent types, intersection types, and object self-references, which serves as the core calculus of Scala 3. Although the calculus has been proven sound, it remains open whether type checking in DOT is decidable. In this paper, we establish undecidability proofs of type checking and subtyping of
D
<:
, a syntactic subset of DOT. It turns out that even for
D
<:
, undecidability is surprisingly difficult to show, as evidenced by counterexamples for past attempts. To prove undecidability, we discover an equivalent definition of the
D
<:
subtyping rules in normal form. Besides being easier to reason about, this definition makes the phenomenon of subtyping reflection explicit as a single inference rule. After removing this rule, we discover two decidable fragments of
D
<:
subtyping and identify algorithms to decide them. We prove soundness and completeness of the algorithms with respect to the fragments, and we prove that the algorithms terminate. Our proofs are mechanized in a combination of Coq and Agda.
Reduction monads and their signatures
Authors: Ahrens Benedikt , Hirschowitz André , Lafont Ambroise , Maggesi Marco
Published: December 2019

In this work, we study
reduction monads
, which are essentially the same as monads relative to the free functor from sets into multigraphs. Reduction monads account for two aspects of the lambda calculus: on the one hand, in the monadic viewpoint, the lambda calculus is an object equipped with a well-behaved substitution; on the other hand, in the graphical viewpoint, it is an oriented multigraph whose vertices are terms and whose edges witness the reductions between two terms.

We study presentations of reduction monads. To this end, we propose a notion of
reduction signature
. As usual, such a signature plays the role of a virtual presentation, and specifies arities for generating operations—possibly subject to equations—together with arities for generating reduction rules. For each such signature, we define a category of models; any model is, in particular, a reduction monad. If the initial object of this category of models exists, we call it the
reduction monad presented (or specified) by the given reduction signature
.

Our main result identifies a class of reduction signatures which specify a reduction monad in the above sense. We show in the examples that our approach covers several standard variants of the lambda calculus.
RustBelt meets relaxed memory
Authors: Dang Hoang-Hai , Jourdan Jacques-Henri , Kaiser Jan-Oliver , Dreyer Derek
Published: December 2019

The Rust programming language supports safe systems programming by means of a strong ownership-tracking type system. In their prior work on RustBelt, Jung et al. began the task of setting Rust’s safety claims on a more rigorous formal foundation. Specifically, they used Iris, a Coq-based separation logic framework, to build a machine-checked proof of semantic soundness for a λ-calculus model of Rust, as well as for a number of widely-used Rust libraries that internally employ unsafe language features. However, they also made the significant simplifying assumption that the language is sequentially consistent. In this paper, we adapt RustBelt to account for the relaxed-memory operations that concurrent Rust libraries actually use, in the process uncovering a data race in the Arc library. We focus on the most interesting technical problem: how to reason about
resource reclamation under relaxed memory
, using a logical construction we call
synchronized ghost state
.
Stacked borrows: an aliasing model for Rust
Authors: Jung Ralf , Dang Hoang-Hai , Kang Jeehoon , Dreyer Derek
Published: December 2019

Type systems are useful not just for the safety guarantees they provide, but also for helping compilers generate more efficient code by simplifying important program analyses. In Rust, the type system imposes a strict discipline on pointer aliasing, and it is an express goal of the Rust compiler developers to make use of that alias information for the purpose of program optimizations that reorder memory accesses. The problem is that Rust also supports unsafe code, and programmers can write unsafe code that bypasses the usual compiler checks to violate the aliasing discipline. To strike a balance between optimizations and unsafe code, the language needs to provide a set of rules such that unsafe code authors can be sure, if they are following these rules, that the compiler will preserve the semantics of their code despite all the optimizations it is doing.

In this work, we propose
Stacked Borrows
, an operational semantics for memory accesses in Rust. Stacked Borrows defines an aliasing discipline and declares programs violating it to have
undefined behavior
, meaning the compiler does not have to consider such programs when performing optimizations. We give formal proofs (mechanized in Coq) showing that this rules out enough programs to enable optimizations that reorder memory accesses around unknown code and function calls, based solely on intraprocedural reasoning. We also implemented this operational model in an interpreter for Rust and ran large parts of the Rust standard library test suite in the interpreter to validate that the model permits enough real-world unsafe Rust code.
Abstract interpretation of distributed network control planes
Authors: Beckett Ryan , Gupta Aarti , Mahajan Ratul , Walker David
Published: December 2019

The control plane of most computer networks runs distributed routing protocols that determine if and how traffic is forwarded. Errors in the configuration of network control planes frequently knock down critical online services, leading to economic damage for service providers and significant hardship for users. Validation via ahead-of-time simulation can help find configuration errors but such techniques are expensive or even intractable for large industrial networks. We explore the use of abstract interpretation to address this fundamental scaling challenge and find that the right abstractions can reduce the asymptotic complexity of network simulation. Based on this observation, we build a tool called ShapeShifter for reachability analysis. On a suite of 127 production networks from a large cloud provider, ShapeShifter provides an asymptotic improvement in runtime and memory over the state-of-the-art simulator. These gains come with a minimal loss in precision. Our abstract analysis accurately predicts reachability for all destinations for 95% of the networks and for most destinations for the remaining 5%. We also find that abstract interpretation of network control planes not only speeds up existing analyses but also facilitates new kinds of analyses. We illustrate this advantage through a new destination "hijacking" analysis for the border gateway protocol (BGP), the globally-deployed routing protocol.
Full abstraction for the quantum lambda-calculus
Authors: Clairambault Pierre , de Visme Marc
Published: December 2019

Quantum programming languages permit a hardware independent, high-level description of quantum algorithms. In particular, the quantum λ-calculus is a higher-order language with quantum primitives, mixing quantum data and classical control. Giving satisfactory denotational semantics to the quantum λ-calculus is a challenging problem that has attracted significant interest. In the past few years, both static (the quantum relational model) and dynamic (quantum game semantics) denotational models were given, with matching computational adequacy results. However, no model was known to be fully abstract.

Our first contribution is a full abstraction result for the games model of the quantum λ-calculus. Full abstraction holds with respect to an observational quotient of strategies, obtained by summing valuations of all states matching a given observable. Our proof method for full abstraction extends a technique recently introduced to prove full abstraction for probabilistic coherence spaces with respect to probabilistic PCF.

Our second contribution is an interpretation-preserving functor from quantum games to the quantum relational model, extending a long line of work on connecting static and dynamic denotational models. From this, it follows that the quantum relational model is fully abstract as well.

Altogether, this gives a complete denotational landscape for the semantics of the quantum λ-calculus, with static and dynamic models related by a clean functorial correspondence, and both fully abstract.