bluuebunny/crossref_metadata_2025 huggingface dataset:
A Study of Transmission Error in Timing Belt Drives: Effect of Production Error in Polychloroprene Rubber Belt
Authors: Kagotani Masanori , Koyama Tomio , Ueda Hiroyuki
Published: March 2021

Experiments on a transmission error, having a period of one revolution of the belt in polychloroprene rubber timing belts, were performed under a quasi-static condition and an initial tension. The experimental results were compared with the computed results obtained using the measurement results of the production error in the belt. It was confirmed that the transmission error was mainly caused by a single pitch error, a change in cross-sectional area of the load carrying cords and a change in modulus of elasticity for one revolution of the belt. As the experimental results coincided quite well with the computed ones, it was concluded that the measurement methods for the single pitch error and the belt elongation factor, and the arrangement methods of these values used to compute the transmission error were right. Further, it was found that the transmission error due to the production error in the belt lessens when the initial tension becomes smaller.
A Globoidal-Cam Type Gearing
Authors: Oizumi Tetusya , Emura Takashi
Published: March 2021

This paper describes a globoidal-cam type gearing with roller-wheel composed of two lines of roller followers to obtain a no-backlash reduction gearing. A principal advantage of this system is the reduction of backlash of the gearing by holding the cam’s rib with the roller followers of each line. We suggest that the roller’s axis should make a reasonable angle to the wheel’s axis. By setting this angle to a suitable amount, the power loss of the gearing will be reduced significantly. The gearing of which roller’s axes are inclined can be applied to high speed and large torque gearing indicating a remarkable improvement upon roller-wheel gearing. A typical globoidal-cam type gearing is analyzed geometrically, its frictional loss of power in meshing is calculated, and a substantial reduction of friction loss was resulted. Additionally, the stiffness of the roller-wheel was estimated and is practically sufficient for our application.
Surface Failure and Durability of Induction-Hardened Sintered Powder Metal Rollers and Gears With Various Hardened Depths
Authors: Yoshida Akira , Ohue Yuji , Karasuno Isamu
Published: March 2021

In this study, the effect of hardened depth on failure modes and fatigue strengths of induction-hardened sintered powder metal test rollers and spur gears is elucidated also with the effect of relative radius of curvature of the test rollers. These experimental results are discussed by an amplitude of ratio of orthogonal shear stress to Vickers hardness. Failure mode of the test rollers was spelling due to subsurface origin crack with slight micropits and that of the test gears was pitting due to surface origin crack with spall near the pitch point independent of the hardened depth. The depths of spalling cracks agreed almost with the occurring depths of peak amplitude of the ratio of orthogonal shear stress to Vickers hardness. Surface durability of the test rollers increased as the surface hardness increased and the relative radius of curvature decreased almost independent of the hardened depth. Surface fatigue life of the test gears was hardly influenced by the hardened depth.
Design for Assembly Evaluation of Orientation Difficulty Features
Authors: Sturges Robert H. , Yang Jui-Te
Published: March 2021

In support of the effort to bring downstream issues to the attention of the designer as parts take shape, an analysis system is being built to extract certain features relevant to the assembly process, such as the dimension, shape, and symmetry of an object. These features can be applied to a model during the downstream process to evaluate handling and assemblability. In this paper, we will focus on the acquisition phase of the assembly process and employ a Design for Assembly (DFA) evaluation to quantify factors in this process. The capabilities of a non-homogeneous, non-manifold boundary representation geometric modeling system are used with an Index of Difficulty (ID) that represents the dexterity and time required to assemble a product. A series of algorithms based on the high-level abstractions of loop and link are developed to extract features that are difficult to orient, which is one of the DFA criteria. Examples for testing the robustness of the algorithms are given. Problems related to nearly symmetric outlines are also discussed.
Development of an Automatic Earring-Post Assembly System Using an Expert System Approach
Authors: Yang Biwu , Datseris Philip , Archer Todd
Published: March 2021

The problem of designing an automatic system to hand posts from bulk, to position them precisely and to weld them on findings, such as earrings, has been effectively solved by employing expert system methodologies and graph theory techniques. Design requirements are represented in terms of desired degrees of freedom, desired type of motion, and the complexity of the mechanism in terms of the number of independent loops. The expert system DOMES, Design of Mechanisms by an Expert System, developed at the University of Rhode Island, is employed to identify several kinematic structures of mechanisms which fulfill all requirements. Present semi-automatic systems require an operator to handle and position findings and posts into a welding machine at rates of approximately sixty findings per minute. The developed system handles four hundred findings per minute. Results show that mechanism design techniques based on graph theory and expert systems are powerful tools for creative mechanism design.

In this paper, emphasis is placed on the design of the mechanical system. However, the developed automatic earring-post assembly system includes several other features. A commercially available fusion welding machine is improved to attain rates of fourteen instead of three welds per second, a fifteen ton power press is integrated into the system and appropriate controls are designed and implemented together with light and acoustic sensors to synchronize the power press, the fusion welding equipment, and the post-handling equipment and to monitor system performance on a real-time basis.
Optimal Design of the Geometric Parameters of a Disk Cam Translating Follower Mechanism Using Chebychev Approximation
Authors: Peng Y. , Zhou J. , Dong Z.
Published: March 2021

A method for the structural design of a cam-translating roller follower mechanism with the minimum volume and least maximum pressure angle is presented. The design is formulated as a two-objective optimization problem subject to multiple constraints. The hierarchical approach for handling multi-objective optimization and application of the Chebychev approximation scheme for solving the nested maximization-minimization problem are discussed. The method presents a forthright approach to the complex optimal structural design of a cam-follower mechanism, and significantly improves present cam-follower mechanism design and optimization methods. A design example is used to illustrate the approach.
Intersection of Rays With Parametric Envelope Surfaces Representing Five-Axis NC Milling Tool Swept Volumes
Authors: Narvekar Ashish P. , Huang Yunching , Oliver James H.
Published: March 2021

A technique based on the theory of envelopes is presented to formulate a parametric representation of the surfaces swept by an axis-symmetric convex solid under general rigid body motion. The resulting swept surfaces are used to build a complete and precise swept volume model of the moving solid. Finally, an algorithm for finding the intersection of a ray with a swept volume is presented. The algorithm is sufficiently general to be useful in a variety of applications, including robotic path planning, design of mechanisms, and the simulation and verification of numerically controlled (NC) milling programs. Several examples of the algorithm are presented demonstrating ray intersections with swept volumes generated by a general seven-parameter NC milling tool model undergoing typical five-axis motion.
A New Damping Model for Non-Linear Stiffness Systems With Variable Preload Displacements and Constant Amplitude Decay Ratios
Authors: Xu T. , Lowen G. G.
Published: March 2021

This study of the behavior of non-linear stiffness systems with variable preload displacements and constant amplitude decay ratios showed that the energy loss per cycle is dependent on these preload displacements. By introducing a non-linear damping force, which is a function of both displacement and velocity, the associated work per cycle can be made approximately the same function of the preload displacement as is the case for the energy loss. In this manner, it becomes possible to make the resulting damping coefficient essentially independent of the preload displacement. This new damping model was incorporated into the mathematical description of an over-running sprag clutch. Confirming experimentation showed very good agreement with computed results.
A Constructive Variational Geometry Based Mechanism Design Software Package
Authors: Todd Philip H.
Published: March 2021

This paper describes the design and implementation of a variational geometry based mechanism design and analysis software package. A new, constructive approach to variational geometry allows positions and their derivatives to be computed using closed form expressions rather than an iterative procedure. This facilitates an interactive kinematics model. Statics and dynamics capabilities are added by means of the principle of least work and d’Alambert’s principle.

Examples are presented which highlight the flexibility and ease of use of the system.
Tolerance Synthesis Method for an Industrial Crank-Rocker Application
Authors: Benner Mark M. , Erdman Arthur G.
Published: March 2021

An emphasis on reducing product development lead-times in the automotive industry has received much attention recently. The synthesis and design of windshield wiper drive mechanisms is no exception. This paper examines and develops the new concept of performance synthesis for crank-rocker linkages with two prescribed positions as applied to windshield wiper systems. Various performance criteria are evaluated with respect to the effect on the desired motion of the crank-rocker linkage by manufacturing tolerances, elastic deflections and joint clearances. Three performance criteria are mapped in the crank-rocker synthesis solution space to aid in the selection of solutions when considering the performance demands of the windshield wiper system. A case study is presented to demonstrate the effectiveness of the new performance synthesis concept which simultaneously considers position tolerance sensitivity, transmission angles and angular acceleration magnitudes in the synthesis process.
A Symbolic-Numerical Approach for the Dynamic Modelling of Parallel Manipulators
Authors: Li Li , Chen Yong
Published: March 2021

A symbolic-numerical approach for the dynamic modelling of parallel manipulators is proposed in this paper. By extending the symbolic algebraic operation rules of the structural matrices and using an improved algorithm for the optimal operation of structural matrices, matrix elements in dynamic equations are generated automatically on the computer with minimization of number of floating-point multiplications/additions.
A Method for the Identification of Displacement Isomorphism of Planetary Gear Trains
Authors: Hsu Cheng-Ho , Lam Kin-Tak
Published: March 2021

The purpose of this paper is to present an efficient method for the identification of the displacement isomorphism of planetary gear trains. For every planetary gear train, the kinematic structure is characterized by its displacement graph and rotation graph. A mathematical representation, called the Structural Code, is introduced to represent the topological structure of the displacement graph and rotation graph of a planetary gear train. Based on the Structural Codes of displacement graphs and rotation graphs, the linear and rotational displacement isomorphism of planetary gear trains can be identified in an unambiguous way. Finally, an interactive computer program is developed for the automatic identification of the displacement isomorphism of planetary gear trains.
The Creation of a Multi-Link Load Balancing Mechanism for Planetary Gearing: Part 1 — Type Synthesis
Authors: Hong Zhang , Yang Ting Li , Chu Jin Kui , Cao Wei-qing
Published: March 2021

This series of papers design a multi-link load balancing mechanism for the Planetary Gearings with arbitrary number of planet gears. Based on the study of SGP load balancing mechanisms, this paper analyzed the relations between the function and kinematic structure of the multilink load balancing mechanism, and presented the topological characteristics and parameters of the kinematic chains suited for load balancing mechanism. Those topological parameters depend on the number of planet gears. In the type synthesis for the case of six planet gears, the kinematic chains with five degrees of freedom and eighteen links were enumerated according to the topological characteristics. The resulting mechanisms were 15 candidate multi-link load balancing mechanism.
A Sequential Implicit-Explicit Integration Method in Solving Nonlinear Differential Equations From Flexible System Modeling
Authors: Xu Jiechi , Baumgarten Joseph R.
Published: March 2021

The dynamic equations of motion obtained in the modeling of flexible structural systems with unknown rigid body gross motion are often highly nonlinear and possess time-varying coefficient matrices. The inherent characters of nonlinear large overall rigid body motion and linear small vibration are also involved in the system equations. Neither the implicit nor the explicit algorithm seems optimally suited and efficient by itself in dealing with these kinds of equations. This paper, therefore, presents a sequential implicit-explicit method in which it is attempted to achieve the attributes of both classes of algorithms. The equation system expressed in matrix form is first mapped to a subsystem in which the specified generalized coordinates are eliminated. The subsystem is then partitioned into two sets of coupled equations. One set of equations, describing the elastic motion, is linear with respect to the elastic generalized coordinates and is integrated implicitly. The other set of equations, governing the rigid body motion, contains the highly nonlinear coupling terms and is integrated explicitly with the back substitutions of the elastic kinematic properties already calculated in solving the first set of equations. A Newmark algorithm is employed to integrate the second order system of differential equations directly. A predictor-corrector scheme also coming from the Newmark algorithm is applied to the explicit integration. The procedures developed in the current paper are applied to simulating dynamic response of a complicated flexible system with mutually dependent rigid body unconstrained spherical motion and small elastic deformation.
Body Vibrations of a Legged Walking Machine
Authors: Gao Xiaochun , Song Shin-Min
Published: March 2021

Unlike in wheeled vehicles, compliance in walking machine systems changes due to the variation of leg geometry, as its body proceeds. This variation in compliance will cause vibration, even if external loads remain constant. A theory is thus developed to predict the body vibrations of a walking machine during walking. On the other hand, dynamic foot forces under body vibrations can be computed by application of the existing numerical methods. As an example, the body vibrations of a quadrupedal walking chair under different walking conditions are simulated in terms of the developed theory. The results show that the influence of body vibrations on the foot force distribution is essential and, in some cases, the walking chair may lose its stability due to its body vibrations, even though it is identified to be stable in a quasi-static analysis. The developed theory can also be extended to other similar multi-limbed robotic systems, such as multi-fingered robot hands.
Forming Dynamic Equations of Elastic Linkage and Investigation of Model Error
Authors: Zou Hui-jun , Zhang Mingli
Published: March 2021

In this paper, the approach in which KANE equation is combined with finite element method is used to derive the dynamic equation of elastic plane linkage. In these equations, arbitrary external forces acted on the linkages, distributive moment of inertia, lumped masses and concertrated moments of inertia set on arbitrary position of the linkage, higher order acceleration, shear, axial force, lengthwise and crosswise bend and rotating matrix are considered.
Inverse Kinematics of General 6R and 5R,P Serial Manipulators
Authors: Kohli Dilip , Osvatic Michael
Published: March 2021

In this paper we present a solution to the inverse kinematics problem for serial manipulators of general geometry. The method is presented in detail as it applies to a 6R manipulator of general geometry. The equations used are derived using a linearization method and dialytic elimination. In doing this, all variables except one, a tangent half angle of a joint variable, can be eliminated. The result is a 16 by 16 matrix in which all terms are linear in the suppressed variable. The unique design of this matrix allows the suppressed variable to be solved as an eigenvalue problem. Substituting these values of the suppressed variable back into the equations, all other joint variables can be found using linear equations. The result is the 16 solutions expected for the 6R case. The same technique is also applicable to manipulators with prismatic joints. We present the solution technique for all six possible 5R,P manipulators through numerical examples. The primary distinction between the technique presented in this paper and recently published Raghavan and Roth (90a,b.c) solution is that they removed two known spurious imaginary roots of multiplicity four to obtain a 16th order polynomial for 6R and 5R,P cases. In our formulation, the 16th degree polynomial can be derived directly without having to remove any spurious imaginary roots. Another distinction is that the solution procedure presented in this paper can be reduced to an eigenvalue problem. This results in significant gains in computation time.
Kinematic Singularities of Free-Floating Open-Chain Planar Manipulators
Authors: Agrawal Sunil Kumar , Rambhaskar J.
Published: March 2021

This paper deals with Jacobian singularities of free-floating open-chain planar manipulators. The problem, in essence, is to find the joint angles where the Jacobian mapping between the end-effector rates and the joint rates is singular. In the absence of external forces and couples, for free-floating manipulators, the linear and angular momentum are conserved. This makes the singular configurations of free-floating manipulators different from structurally similar fixed-base manipulators. In order to illustrate this idea, we present a systematic method to obtain the singular solutions of a free-floating series-chain planar manipulator with revolute joints. We show that the singular configurations are solutions of simultaneous polynomial equations in the half-tangent of the joint variables. From the structure of these polynomial equations, we estimate the upper bound on the number of singularities of free-floating planar manipulators and compare these with analogous results for structurally similar fixed-base manipulators.
Nonparametric Object Recognition With a New Tactile Sensor
Authors: Unsal S. , Shirkhodaie A. , Soni A. H.
Published: March 2021

Adding sensing capability to a robot provides the robot with intelligent perception capability and flexibility of decision making. To perform intelligent tasks, robots are highly required to perceive their operating environment, and react accordingly. With this regard, tactile sensors offer to extend the scope of intelligence of a robot for performing tasks which require object touching, recognition, and manipulation.

This paper presents the design of an inexpensive pneumatic binary-array tactile sensor for such robotic applications. The paper describes some of the techniques implemented for object recognition from binary sensory information. Furthermore, it details the development of software and hardware which facilitate the sensor to provide useful information to a robot so that the robot perceives its operating environment during manipulation of objects.
Generation of Surface Models of 3D Objects From Their Wire-Frame Models
Authors: Gupta S. , Shirkhodaie A. , Soni A. H.
Published: March 2021

This paper presents an algorithm to generate surface models of 3D objects from their wire-frame models. The algorithm firstly, obtains information about edges of the object from the wire-frame model of the object and uses this edge information to generate the pairs. A pair of an object is a combination of two non-collinear edges which have a common vertex. The algorithm then determines the unique plane passing through each pair and groups the coplanar pairs together. Then it sorts each of the groups of coplanar pairs to form one or more loops of edges. Finally for each group of coplanar pairs, all the loops are combined, using a few rules, to form faces of the object. Hence a surface model of the object is generated.
Robotic Assembly Cell Simulation
Authors: Liu Jian , Sadler J. P.
Published: March 2021

A flexible robotic assembly cell is described, and some of the research activities involving the cell and robot applications in manufacturing environments are presented. This research relies heavily on computer simulation. Assembly cell computer modeling, cell calibration, robot collision detection, and off-line programming are described in this paper.
Extensional hardening of multimodal, linear PE with high amounts of UHMWPE
Authors: Szántó L. , Feng Y. , Friedrich C.
Published: March 2021

Until the advent of the novel Enders catalysts, the nonlinear rheological characterization of polyethylene (PE) blends, containing up to 50 wt. % of ultra-high molecular weight PE (UHMWPE, with weight average molecular weight Mw > 106 g/mol) was unattainable. In this study, by melt blending of a commercially available high-density PE (polymer matrix) and PE-reactor-blends (RBs), multimodal PE blends were prepared, and their nonlinear viscoelastic properties were investigated. The experiments revealed how extraordinarily high amount of UHMWPE content and ultra-broad molecular weight distribution characterized by well separated molecular weight modes influence the nonlinear viscoelasticity. Furthermore, in order to evaluate the strain hardening ability of the multimodal PE, an approach was proposed allowing to objectively analyze and quantify the nonlinear response of the investigated samples. Analyzing the “state diagram” of the extended specimens, which captures the melt behavior and flow instabilities during uniaxial extensional measurements, unveiled that the observed SH of multimodal PE blends, at temperatures notably higher than their melting temperature, is controlled by the stretched chains of the 2nd well separated UHMWPE molecular weight mode. Moreover, it was found that, in order to highly stretch the PE chains, a characteristic strain must be applied.
Breaching a Contract Versus Searching for a Job While Employed: Ethical Dilemmas Faced by Coaches and Administrators When Deciding About a Mid-Season Change in Leadership
Authors: Smith Allison , Gioseffi Yan , Graham Jeffrey
Published: March 2021

The Pointers are a soccer team that play in Division A of the Demolition League. The president of the Pointers is Fernando Garcia, and the head coach is Guille Muller. The league has a poor culture of firing coaches throughout the season. With only a couple of games left in the season, the Pointers are going through a losing streak, and there are rumors Muller may be fired if the team does not win their next game. Simultaneously, Muller is receiving coaching offers from other teams within the league. The ethical dilemma surrounding this case refers to two scenarios (a) whether it is ethical for the president to negotiate with another coach while there is still one employed and (b) whether it is ethical for a coach to negotiate with another club while employed. Drawing from research in sport management, this case focuses on three ethical theories to create discussion surrounding the scenario: Utilitarianism, Deontology, and Virtue Ethics. Undergraduate and graduate students in sport management, human resources, and those who seek to be in a leadership position will have the opportunity to understand, analyze, and discuss these three theories and apply them to real-life scenarios, such as hiring and firing employees.
Physiological and Perceptual Recovery-Stress Responses to an Elite Netball Tournament
Authors: Russell Suzanna , Simpson Marni J. , Evans Angus G. , Coulter Tristan J. , Kelly Vincent G.
Published: March 2021

Purpose: To investigate and explore the relationships between physiological and perceptual recovery and stress responses to elite netball tournament workloads. Methods: Nine elite female netballers were observed across a 3-day (T1–3), 4-match tournament. Participants provided salivary samples for cortisol and alpha-amylase analysis, completed the Short Recovery Stress Scale (SRSS), and reported session ratings of perceived exertion. Inertial measurement units and heart-rate monitors determined player load, changes of direction (COD), summated heart-rate zones, and jumps. Results: Analysis revealed 6 significant SRSS time effects: (1) decreased recovery markers of physical performance (P = .042), emotional balance (P = .034), and overall recovery (P = .001) and (2) increased perceptual stress markers of muscular stress (P = .001), negative emotional state (P = .026), and overall stress (P = .010). Salivary cortisol decreased over the tournament (T1–3) before progressively increasing posttournament with greater salivary samples for cortisol on T+2 compared with T3 (P = .014, ES = −1.29; −2.24 to −0.22]) and T+1 (P = .031, ES = −1.54; −2.51 to −0.42). SRSS overall recovery moderately negatively correlated with COD (r = −.41, P = .028) and session ratings of perceived exertion (r = −.40, P = .034). Cumulative workload did not relate to posttournament perceptual or salivary responses. Percentage change in salivary variables related (P < .05) to total player load, total COD, and overall recovery across specific cumulative time periods. Conclusions: During and after an elite netball tournament, athletes indicated increased perceptual stress and lack of recovery. The SRSS is a valuable tool for recovery–stress monitoring in elite tournament netball. It is recommended that practitioners monitor COD due to its negative influence on perceived overall recovery.
Comment on “Large-scale GWAS reveals insights into the genetic architecture of same-sex sexual behavior”
Authors: Hamer Dean , Mustanski Brian , Sell Randall , Sanders Stephanie A. , Garcia Justin R.
Published: March 2021

The phenotypic measures used by Ganna
et al
. (Research Articles, 30 August 2019, p. 882) lump together predominantly heterosexual, bisexual, and homosexual individuals, including those who have experimented with a same-sex partner only once. This may have resulted in misleading associations to personality traits unrelated to understood categories of human sexuality. Scientific studies of human sexuality should use validated and reliable measures of sexual behaviors, attractions, and identities that capture the full spectrum of complexity.
HLA-E–restricted, Gag-specific CD8
+
T cells can suppress HIV-1 infection, offering vaccine opportunities
Authors: Yang Hongbing , Rei Margarida , Brackenridge Simon , Brenna Elena , Sun Hong , Abdulhaqq Shaheed , Liu Michael K. P. , Ma Weiwei , Kurupati Prathiba , Xu Xiaoning , Cerundolo Vincenzo , Jenkins Edward , Davis Simon J. , Sacha Jonah B. , Früh Klaus , Picker Louis J. , Borrow Persephone , Gillespie Geraldine M. , McMichael Andrew J.
Published: March 2021

CD8
+
T cells that recognize a Gag peptide presented by HLA-E suppress HIV-1 replication in vitro.
Population Pharmacokinetics and Outcomes of Critically Ill Pediatric Patients Treated with Intravenous Colistin at Higher Than Recommended Doses
Authors: Antachopoulos Charalampos , Geladari Anastasia , Landersdorfer Cornelia B. , Volakli Eleni , Ilia Stavroula , Gikas Evangelos , Gika Helen , Sdougka Maria , Nation Roger L. , Roilides Emmanuel
Published: March 2021

Limited pharmacokinetic (PK) data suggest that currently recommended pediatric dosages of colistimethate sodium (CMS) by the Food and Drug Administration and European Medicines Agency may lead to suboptimal exposure, resulting in plasma colistin concentrations that are frequently <2 mg/liter. We conducted a population PK study in 17 critically ill patients 3 months to 13.75 years (median, 3.3 years) old who received CMS for infections caused by carbapenem-resistant Gram-negative bacteria.
A Dengue Virus Serotype 1 mRNA-LNP Vaccine Elicits Protective Immune Responses
Authors: Wollner Clayton J. , Richner Michelle , Hassert Mariah A. , Pinto Amelia K. , Brien James D. , Richner Justin M.
Published: March 2021

With 400 million worldwide infections each year, dengue is the most common vector-borne viral disease. Forty percent of the world's population is at risk, with dengue experiencing consistent geographic spread over the years.
Detection of Pathogens and Regulation of Immunity by the Caenorhabditis elegans Nervous System
Authors: Liu Yiyong , Sun Jingru
Published: March 2021

Although
Caenorhabditis elegans
has been used as a model host for studying host-pathogen interactions for more than 20 years, the mechanisms by which it identifies pathogens are not well understood. This is largely due to its lack of most known pattern recognition receptors (PRRs) that recognize pathogen-derived molecules.
Load-matched acute and chronic exercise induce changes in mitochondrial biogenesis and metabolic markers
Authors: Rodrigues Natália Almeida , Gobatto Claudio Alexandre , Forte Lucas Dantas Maia , Sousa Filipe Antônio de Barros , Torsoni Adriana Souza , Fante Thais de , Manchado-Gobatto Fúlvia Barros
Published: March 2021

We investigated the effects of acute and chronic exercise, prescribed in different intensity zones, but with total load-matched on mitochondrial markers (cytochrome C oxidase subunit IV (COX-IV), mitochondrial transcription factor A (Tfam), and citrate synthase (CS) activity in skeletal muscles, heart, and liver), glycogen stores, aerobic capacity, and anaerobic index in swimming rats. For this, 2 experimental designs were performed (acute and chronic efforts). Load-matched exercises were prescribed below, above, and on the anaerobic threshold (AnT), determined by the lactate minimum test. In chronic programs, 2 training prescription strategies were assessed (monotonous and linear periodized model). Results show changes in glycogen stores but no modification in the COX-IV and Tfam contents after acute exercises. In the chronic protocols, COX-IV and Tfam proteins and CS adaptations were intensity- and tissue-dependent. Monotonous training promoted better adaptations than the periodized model. Training at 80% of the AnT improved both performance variables, emphasizing the anaerobic index, concomitant to CS and COX-IV improvement (soleus muscle). The aerobic capacity and CS activity (gastrocnemius) were increased after 120% AnT training. In conclusion, acute exercise protocol did not promote responses in mitochondrial target proteins. An intensity and tissue dependence were reported in the chronic protocols, highlighting training at 80 and 120% of the AnT.

Novelty: Load-matched acute exercise did not enhance COX-IV and Tfam contents in skeletal muscles, heart, and liver. In chronic exercise, COX-IV, Tfam, and CS activity adaptations were intensity- and tissue-dependent. Monotonous training was more efficient than the periodized linear model in adaptations of target proteins and enzymatic activity.
Cumulate gabbros in the South Andaman Island ophiolite suite (India): their bearing on the tectonic setting
Authors: Akhtar Salim , Negi Priyanka , Saikia Ashima
Published: March 2021

The Andaman ophiolite of southeastern India is located on the outer arc of the Andaman–Java subduction zone. It is represented by thrust slices formed in the Mesozoic Neo-Tethys Ocean. Lithologically, it consists of dismembered mafic and ultramafic rocks and associated oceanic pelagic sediments. The present study focuses on the mafic cumulate rocks of the Andaman ophiolite preserved in the Kodiaghat and Munda Pahar area of South Andaman Island. The mafic cumulates are represented by olivine-bearing and olivine-free gabbros. The sequence of crystallization in the gabbros is olivines (Fo∼80) ± chromian spinels (Cr# = 57–59), plagioclases (An61–95), clinopyroxenes (Mg# = 82–89), and amphiboles (Mg–hornblende, edenite, and pargasite). Major oxide and trace element whole-rock geochemistry and mineral compositions are consistent with a hybrid signature of island arc tholeiite (IAT) – mid-oceanic ridge basalt (MORB). Geochemical modelling shows that trapped melt fractions of 0%–20% can produce the observed trace element signatures of these gabbros. Our findings suggest that the gabbroic cumulates of the Andaman ophiolite were formed in an oceanic back-arc and oceanic arc setting developed in the Neo-Tethys oceanic domain between the Indian and Burmese plates during the Late Cretaceous.
An enigmatic mass mortality event of Blanding’s Turtles (Emydoidea blandingii) in a protected area
Authors: Gasbarrini D.M.L. , Lesbarrères D. , Sheppard A. , Litzgus J.D.
Published: March 2021

Mass mortality events (MMEs) can remove up to 90% of individuals in a population and are especially damaging to population viability of long-lived species with slow life histories. Our goal was to elucidate the cause(s) of a MME of 53 Blanding’s Turtles (Emydoidea blandingii (Holbrook, 1838)), a globally endangered species, in a protected area. We investigated disease, winter-kill, and depredation as potential causes of the mortality. The turtle carcasses lacked soft tissue to test for disease, so we examined tissue from co-occurring live Leopard Frogs (Lithobates pipiens (Schreber, 1782)) and found no evidence of ranavirus, indicating that the disease was not present at our study site. Water temperature and dissolved aquatic oxygen at known overwintering sites and sites which yielded carcasses did not differ, suggesting that winter-kill did not cause the MME. Carcass condition, comparisons with descriptions of turtle depredation events in the literature, and trail cameras paired with turtle decoys identified potential predators within the study site and suggested that mass depredation, enabled by low water levels and a concomitant reduction in aquatic habitat, was the most likely cause of mortality. Our study can inform conservation of the study population and the management of MMEs of long-lived species elsewhere.
The need for a federal Basic Income feature within any coherent post-COVID-19 economic recovery plan
Authors: Segal Hugh , Banting Keith , Forget Evelyn
Published: March 2021

COVID-19 has shone a harsh light on the extent of poverty in Canada. When normal economic activity was interrupted by the exigencies of public health driven lockdowns, the shutdown disproportionately affected people who, before the pandemic, were living on incomes beneath the poverty line or dependent upon low-paying hourly remunerated jobs, usually part time and without appropriate benefits. Those living beneath the poverty line in Canada, three million of welfare poor and working poor, include a disproportionately large population of Black and Indigenous people and people of colour. This paper addresses the challenge of inclusive economic recovery. In particular, we propose that the federal government introduce a Basic Income guarantee for all residents of Canada as part of a comprehensive social safety net that includes access to housing, child care, mental and physical health care, disability supports, education, and the many other public services essential to life in a high-income country. Residents with no other income would receive the full benefit that would be sufficient to ensure that no one lives in poverty, while those with low incomes would receive a reduced amount.
Kerr metric Killing bundles
Authors: Pugliese D. , Quevedo H.
Published: March 2021

We provide a complete characterization of the metric Killing bundles (or metric bundles) of the Kerr geometry. Metric bundles can be generally defined for axially symmetric spacetimes with Killing horizons and, for the case of Kerr geometries, are sets of black holes (BHs) or black holes and naked singularities (NSs) geometries. Each metric of a bundle has an equal limiting photon (orbital) frequency, which defines the bundle and coincides with the frequency of a Killing horizon in the extended plane. In this plane each bundle is represented as a curve tangent to the curve that represents the horizons, which thus emerge as the envelope surfaces of the metric bundles. We show that the horizons frequency can be used to establish a connection between BHs and NSs, providing an alternative representation of such spacetimes in the extended plane and an alternative definition of the BH horizons. We introduce the concept of inner horizon confinement and horizons replicas and study the possibility of detecting their frequencies. We study the bundle characteristic frequencies constraining the inner horizon confinement in the outer region of the plane i.e. the possibility of detect frequency related to the inner horizon, and the horizons replicas, structures which may be detectable for example from the emission spectra of BHs spacetimes. With the replicas we prove the existence of photon orbits with equal orbital frequency of the horizons. It is shown that such observations can be performed close to the rotation axis of the Kerr geometry, depending on the BH spin. We argue that these results could be used to further investigate black holes and their thermodynamic properties.
Polynomial duality-symmetric lagrangians for free p-forms
Authors: Bansal Sukruti , Evnin Oleg , Mkrtchyan Karapet
Published: March 2021

We explore the properties of polynomial Lagrangians for chiralp-forms previously proposed by the last named author, and in particular, provide a self-contained treatment of the symmetries and equations of motion that shows a great economy and simplicity of this formalism. We further use analogous techniques to construct polynomial democratic Lagrangians for generalp-forms where electric and magnetic potentials appear on equal footing as explicit dynamical variables. Due to our reliance on the differential form notation, the construction is compact and universally valid for forms of all ranks, in any number of dimensions.
Effect of γ-radiation on magneto-thermoelectric properties of the extruded samples of Bi85Sb15〈Te〉 solid solution
Authors: Abdullayeva I. A. , Abdinova G. D. , Tagiyev M. M. , Samedov O. A.
Published: March 2021

Extruded samples of [Formula: see text] solid solutions doped with 0.0005 at.% Te were obtained and the electrical conductivity [Formula: see text], thermoelectric power (Seebeck) [Formula: see text], Hall [Formula: see text] and thermal conductivity [Formula: see text] coefficients were investigated in the range [Formula: see text]–300 K samples and magnetic field strength up to [Formula: see text] A/m, as annealed after extrusion, non-irradiated with gamma-quanta and the same samples irradiated with gamma quanta at different doses. It was found that at low doses (1 Mrad) of irradiation, radiation defects (RDs) appear in the samples which play the role of donor centers, as a result of which the concentration of free electrons [Formula: see text], and, consequently the electrical conductivity [Formula: see text] increases, and the Seebeck coefficient [Formula: see text] decreases. These defects, scattering the current carriers, reduce their mobility [Formula: see text]. With an increase in the radiation dose, the concentration of defects also increases and free carriers are captured at the level of the RD. In this regard, the concentration of charged carrier defects [Formula: see text] and, consequently, [Formula: see text] of the sample decrease, while the Seebeck coefficient and mobility increase. The effect of a magnetic field on the electrical and thermal parameters of extruded solid solution samples also depends on the radiation dose in the sample.
Thesaurus racks: Categorizing rack objects
Authors: Grøsfjeld Tobias
Published: March 2021

We define and explore rack objects internal to categories with products. In demonstration, we classify the group-racks, and use homotopy to prove both existence and exclusion theorems for path-connected topological racks.
Group presentations for links in thickened surfaces
Authors: Silver Daniel S. , Williams Susan G.
Published: March 2021

Using a combinatorial argument, we prove the well-known result that the Wirtinger and Dehn presentations of a link in 3-space describe isomorphic groups. The result is not true for links [Formula: see text] in a thickened surface [Formula: see text]. Their precise relationship, as given in [R. E. Byrd, On the geometry of virtual knots, M.S. Thesis, Boise State University (2012)], is established here by an elementary argument. When a diagram in [Formula: see text] for [Formula: see text] can be checkerboard shaded, the Dehn presentation leads naturally to an abelian “Dehn coloring group,” an isotopy invariant of [Formula: see text]. Introducing homological information from [Formula: see text] produces a stronger invariant, [Formula: see text], a module over the group ring of [Formula: see text]. The authors previously defined the Laplacian modules [Formula: see text] and polynomials [Formula: see text] associated to a Tait graph [Formula: see text] and its dual [Formula: see text], and showed that the pairs [Formula: see text], [Formula: see text] are isotopy invariants of [Formula: see text]. The relationship between [Formula: see text] and the Laplacian modules is described and used to prove that [Formula: see text] and [Formula: see text] are equal when [Formula: see text] is a torus.
Co-dimension two spinal open book embeddings of 3-manifolds
Authors: Pandit Suhas , Selvakumar A.
Published: March 2021

In this paper, we show that every spinal open book decomposition of a closed oriented [Formula: see text]-manifold [Formula: see text] spinal open book embeds into a certain spinal open book decomposition of [Formula: see text], the connected sum of [Formula: see text] copies of the twisted [Formula: see text]-bundle over [Formula: see text], where [Formula: see text] depends on the spinal open book decomposition of [Formula: see text]. We also discuss spinal open book embeddings of a huge class of spinal open books of closed oriented [Formula: see text]-manifolds into the trivial spinal open book of the [Formula: see text]-sphere [Formula: see text]. Finally, we show that given a closed oriented [Formula: see text]-manifold [Formula: see text], there exists a spinal open book for [Formula: see text] such that [Formula: see text] spinal open book embeds into the trivial spinal open book of [Formula: see text] In particular, this gives another proof of Hirsch’s theorem which states that every closed orientable [Formula: see text]-manifold embeds in [Formula: see text]
Implications of the generalized uncertainty principle on the Walecka model equation of state and neutron star structure
Authors: Abac Adrian G. , Esguerra Jose Perico H.
Published: March 2021

We explore the implications of the generalized uncertainty principle (GUP) on the nuclear equation of state (EoS) and on the structure of neutron stars. Two approaches of GUP are used: the quadratic GUP approach, satisfying minimal length and the linear GUP approach, satisfying both minimal length and maximal momentum. The resulting invariant phase space volumes from these GUP approaches are applied to the [Formula: see text]-[Formula: see text] or Walecka model, serving as a starting point for neutron matter in the relativistic mean field theory. We find that linear GUP increases the range of energy densities corresponding to instabilities in the [Formula: see text]-[Formula: see text] EoS, while quadratic GUP decreases it. A stable EoS was constructed from the GUP-modified EoS via Maxwell construction, and this was fed into the Tolman–Oppenheimer–Volkoff equations and the mass–radius relation of neutron stars was obtained. We observe linear GUP to decrease both the maximum mass and limiting radius of the neutron star, while shifting the whole mass–radius relation to the low-radius regime. Meanwhile, quadratic GUP increases the maximum mass and limiting radius, and the mass-radius relation is shifted to the high-radius regime. The effects that are observed for both GUP modifications in the EoS and mass–radius relations get more prominent as we increase the values of the still unknown GUP parameters.
Manned Aircraft and Unmanned Aerial Vehicle Heterogeneous Formation Flight Control via Heterogeneous Pigeon Flock Consistency
Authors: Huo Mengzhen , Duan Haibin , Ding Xilun
Published: March 2021

The heterogeneous pigeon flock showed higher leadership stability than the homogeneous flock. In this paper, a control model applied to manned aircraft and Unmanned Aerial Vehicle heterogeneous formation flight is designed. During the smoothing trajectory, the swarm employed the distributed communication network and event-triggered interactive mechanism. During the turning trajectory, the centralized and distributed communication networks were integrated. Simulation tests demonstrated that the proposed control algorithm was feasible to form a cohesive group and effectively avoid obstacles in unknown environment.
A comparative performance evaluation of banking industry in Bangladesh: CAMEL rating approach
Authors: Ali Md. Rostam , Ratul Md. Rakibuzzaman , Tisha Rushafa Tasnim , Islam Md. Ashikul
Published: March 2021

This study is an attempt to evaluate and compare the performance of State-Owned Commercial Banks (SOCBs) and Private Commercial Banks (PCBs) of Bangladesh. CAMEL rating model has been applied to confess where a bank can be successful and where it has weaknesses. Data have been collected from four SOCBs and eight PCBs for the years 2014–2017. Among the selected SOCBs, it is found that Agrani Bank holds “Satisfactory” position where Sonali Bank holds “Fair” position through the year 2014–2017. On the other hand, Janata bank has improved its position from “Fair” to “Satisfactory” for the year 2016 and 2017. Moreover, Rupali Bank holds ‘Satisfactory’ position only for the year 2017 where this position was “Fair” for the year 2014–2016. On the other hand, it is found that all the selected PCBs hold “Satisfactory” position through the year 2014–2017. Though the composite rating for both types of banks (SOCBs and PCBs) is in “Satisfactory level”, Rank-1 is given to PCBs and Rank-2 is given to SOCBs. CAMEL ratio for “Asset quality” for both types of banks (SOCBs and PCBs) are showing “Dissatisfactory level”. “Earning quality” of SOCBs is showing at a “Marginal level”. Therefore, proper attention should be given to manage the “Asset quality” and SOCBs should increase the “Earning quality”.