Asymmetric Paths Research Articles

Asymmetrical forward and reverse developmental trajectories determine molecular programs of B cell antigen receptor editing.

During B lymphopoiesis, B cell progenitors progress through alternating and mutually exclusive stages of clonal expansion and immunoglobulin (Ig) gene rearrangements. Great diversity is generated through the stochastic recombination of Ig gene segments encoding heavy and light chain variable domains. However, this commonly generates autoreactivity. Receptor editing is the predominant tolerance mechanism for self-reactive B cells in the bone marrow (BM). B cell receptor editing rescues autoreactive B cells from negative selection through renewed light chain recombination first at Igκ then Igλ loci. Receptor editing depends on BM microenvironment cues and key transcription factors such as NF-κB, FOXO, and E2A. The specific BM factor required for receptor editing is unknown. Furthermore, how transcription factors coordinate these developmental programs to promote usage of the λ chain remains poorly defined. Therefore, we used two mouse models that recapitulate pathways by which Igλ light chain-positive B cells develop. The first has deleted J kappa (Jκ) genes and hence models Igλ expression resulting from failed Igκ recombination (Igκdel). The second models autoreactivity by ubiquitous expression of a single-chain chimeric anti-Igκ antibody (κ-mac). Here, we demonstrated that autoreactive B cells transit asymmetric forward and reverse developmental trajectories. This imparted a unique epigenetic landscape on small pre-B cells, which opened chromatin to transcription factors essential for Igλ recombination. The consequences of this asymmetric developmental path were both amplified and complemented by CXCR4 signaling. These findings reveal how intrinsic molecular programs integrate with extrinsic signals to drive receptor editing.

The Underlying Mechanism and Behavioural Outcomes of Working from Home During the Lockdown

Purpose -This paper examines the implications of remote working on employees’ well-being during the COVID-19 lockdown. To this aim, we invoked boundary theory and source attribution perspective. We identified the underlying mechanisms and within-domain (i.e., family) behavioural outcomes when work and home are physically intertwined during the pandemic. Design-A theoretical model is proposed and empirically tested in a two-waves study of 141 university teachers in London, England (N = 282), who adapted remote working with computer-based assisted technology during the pandemic. Findings Our findings revealed that family-to-work interruption increases family-work conflict and the consequent spouse undermining behaviour. However, the extent to which employees engage in undermining behaviour at home depends on how these interruptions delay work goals achievement (Path A). In the alternative path, we observed that work interrupting during family time directly increases work-family conflict and is only partially explained by family goal obstruction (Path B). Originality/value This study was the first to use source attribution perspective to extend boundary theory and specify, in two asymmetrical paths, a different mechanism for the effect of work-to-family and family-to-work interruptions, WFC/FWC and their within-domain behaviour outcomes. Keywords-Boundary theory; Source attribution theory; Spouse undermining behaviour; Work-family conflict, Family-work conflict; London, UK, COVID-19 pandemic.

Post-Eruptive Persistent Cooling Beneath the Summit Crater of Usu Volcano as Revealed by Magnetic Repeat Surveys

Remarkable and continuous geomagnetic field change, suggesting remagnetization at a shallow depth, was detected through repeated geomagnetic field observation of the summit area of Mt. Usu Volcano from 2008 to 2021. Long-term cooling of the remnant magma, that intruded during the 1977–82 eruption, was considered responsible for the remagnetization. A magnetic dipole parallel to the present geomagnetic field well reproduced the observation. The modeled source was located near the Ginnuma crater on the south side of the previously inferred intrusive body beneath the Usu-Shinzan cryptodome. Meanwhile, no magnetic source was detected on the other side of the intrusion, implying asymmetric heat transport paths around the intrusion. Considering previous studies on seismicity, geodetic modeling, and resistivity structure, the magnetic source region is plausibly a high permeability zone through which heat from the intruded magma has been efficiently transported. In other words, the source region can be a key monitoring target for future eruptions as it may be linked to the subsurface magma system.

A mixed mode elasto-plastic damage model for prediction of failure in single lap joint

In this paper, a pressure-dependent elasto-plastic continuum damage model is derived to account for the elasto-plastic behaviour as well as the gradual damage evolution in the single lap joint (SLJ) using thermodynamic principals. The damage onset is activated by the pressure-dependent loading criterion similar to the yield condition. The total energy release rate is equal to the critical energy release rate as in CZM. This means that the proposed model belongs to a continuum damage model adapting to CZM. However, the present model is different in that it applies the actual pressure-dependent continuum elasto-plastic constitutive relation before the damage onset. Both examples (a symmetric and an asymmetric SLJ) validate that the current model depicts not only the plastic behavior but also damage evolution. An example for the asymmetric SLJ shows that the asymmetric damage evolution and asymmetric crack propagation path in the adhesive layer may be captured using the current model. User material subroutine UMAT in ABAQUS/Standard is used to implement the current model.

Design and Analysis of a Doubly Salient Wound Field Starter Generator for Cost-Effective Automobile Application

Doubly salient wound field machines exhibit the advantages of robust structure and controllable flux, and hence have been utilized as generators in applications of automobiles and renewable energy. However, the inherent unbalanced phase back-electromotive force (EMF) waveform caused by the asymmetric flux path brings difficulties for precise control and smooth operation. To solve the problem caused by unbalanced back-EMF waveform in conventional doubly salient machines, this paper presents a novel doubly salient wound field machine with balanced and symmetrical back-EMF waveform as starter generator in automobile application. The robust structure and the controllable flux are inherited, while the magnetless feature makes it promising for cost-sensitive applications. The proposed machine can be operated as an assistant motor for torque boosting at start-up stage, as well as a power recycling generator for battery charging at steady state. It is revealed that the proposed wound field machine exhibits similar cost, comparable torque density, improved torque ripple, and higher efficiency than the switched reluctance machine. Finally, the proposed prototype is fabricated, and dynamic experiment is conducted to validate the feasibility for automobile starter generator application.

Arbiter Physical Unclonable Functions with Asymmetric Pairs of Paths

The methods of constructing physical unclonable functions (PUF), which are the basis of physical cryptography, are analyzed. The broad applicability of the Arbiter PUF, based on the analysis of the delays of the signal transmitted along two paths, is noted. It is shown that the randomness of the delays is explained by technological variations in the manufacturing process of PUF and their dependence on the use of homogeneous repeating elements that ensure the symmetry of the paths. As an alternative to the existing solutions, the article proposes a new approach for constructing an Arbiter PUF based on asymmetric paths. The sources of randomness as logical element delays are investigated. Their diversity and distinctive characteristics are shown depending on the number of inputs to which an active signal is supplied and the values at other inputs. A technique for balancing a set of pairs of paths of Arbiter PUF is proposed, which lays in regulating the duration of the impulse test signal depending on four types of path asymmetry. New structures of Arbiter PUF with asymmetric pairs of paths are proposed. Experimental studies confirm the possibility of using various sources of randomness in the form of signal delays.

Adaptively Informed Trees (AIT*) and Effort Informed Trees (EIT*): Asymmetric bidirectional sampling-based path planning

Optimal path planning is the problem of finding a valid sequence of states between a start and goal that optimizes an objective. Informed path planning algorithms order their search with problem-specific knowledge expressed as heuristics and can be orders of magnitude more efficient than uninformed algorithms. Heuristics are most effective when they are both accurate and computationally inexpensive to evaluate, but these are often conflicting characteristics. This makes the selection of appropriate heuristics difficult for many problems. This paper presents two almost-surely asymptotically optimal sampling-based path planning algorithms to address this challenge, Adaptively Informed Trees (AIT*) and Effort Informed Trees (EIT*). These algorithms use an asymmetric bidirectional search in which both searches continuously inform each other. This allows AIT* and EIT* to improve planning performance by simultaneously calculating and exploiting increasingly accurate, problem-specific heuristics. The benefits of AIT* and EIT* relative to other sampling-based algorithms are demonstrated on 12 problems in abstract, robotic, and biomedical domains optimizing path length and obstacle clearance. The experiments show that AIT* and EIT* outperform other algorithms on problems optimizing obstacle clearance, where a priori cost heuristics are often ineffective, and still perform well on problems minimizing path length, where such heuristics are often effective.

Will catering employees’ job dissatisfaction lead to brand sabotage behavior? A study based on conservation of resources and complexity theories

PurposeIntegrating conservation of resources (COR) and complexity theories, this study aims to develop and assess a research model of the relationship between job dissatisfaction and brand sabotage behavior (BSB) based on the moderating mechanism of psychological resources (i.e. brand-based role identity and relational energy). The interdependence between these influencing factors is analyzed from the perspective of social science holism.Design/methodology/approachA total of 381 valid questionnaires were collected from frontliners serving in full-service restaurants in Guangzhou, China. Regression analysis was used to test the research hypotheses and combined with fuzzy-set qualitative comparative analysis to identify the complex triggering mechanism of BSB.FindingsJob dissatisfaction is positively related to BSB, brand-based role identity internalization and relational energy weaken this effect, whereas brand-based role identity compliance strengthens it. Qualitative comparative analysis shows that a single condition does not constitute a necessary condition for BSB. The interdependence of job dissatisfaction and employee psychological resources forms multiple asymmetric paths that trigger high and low BSB.Practical implicationsThe findings can be used by catering organizations as guidelines for conducting training for brand internalization, formulating strategies to avoid BSB among employees and strengthening brand building.Originality/valueThis study is the first to integrate COR and complexity theories to comprehensively analyze how BSB is formed among dissatisfied employees. The authors advance theory by distinguishing the role of brand psychological resources (i.e. brand-based role identity) and psychological resources obtained from the environment (i.e. relational energy) in stimulating or buffering dissatisfied employees to engage in BSB.

Learning in Sequential Bilevel Linear Programming

We consider a framework for sequential bilevel linear programming in which a leader and a follower interact over multiple time periods. In each period, the follower observes the actions taken by the leader and reacts optimally, according to the follower’s own objective function, which is initially unknown to the leader. By observing various forms of information feedback from the follower’s actions, the leader is able to refine the leader’s knowledge about the follower’s objective function and, hence, adjust the leader’s actions at subsequent time periods, which ought to help in maximizing the leader’s cumulative benefit. We show that greedy and robust policies adapted from previous work in the max-min (symmetric) setting might fail to recover the optimal full-information solution to the problem (i.e., a solution implemented by an oracle with complete prior knowledge of the follower’s objective function) in the asymmetric case. In contrast, we present a family of greedy and best-case policies that are able to recover the full-information optimal solution and also provide real-time certificates of optimality. In addition, we show that the proposed policies can be computed by solving a series of linear mixed-integer programs. We test policy performance through exhaustive numerical experiments in the context of asymmetric shortest path interdiction, considering various forms of feedback and several benchmark policies.

Evaluation of reactive service function path discovery in symmetrical environment

In this paper we continue our study of path discovery process for Service Function Chaining (SFC) in Software Defined Network (SDN). By default, service function (SF) paths are established proactively - before data transmission takes place. We have argued that this constraint can be eliminated with the use of our proposed Reactive SF path discovery approach. Such SFs as network address translation (NAT) or stateful firewall (FW) are SF path's symmetry dependent requiring a visit of both ingress and egress flows. Thus, we evaluated SF path discovery processes in Mininet emulation network. Outcome of this study is a comparison of proactive and reactive SF path discovery processes for both asymmetrical and symmetrical SF paths. It shows that even in symmetrical environment reactive SF path discovery has a higher probability of successful SF path detection.

Progressive collapse resistance of composite frame with concrete-filled steel tubular column under a penultimate column removal scenario

In this study, static tests of six two-story three-span composite frames with concrete-filled steel tubular (CFST) column under a penultimate column removal scenario were carried out. The experimental phenomena, vertical resistance, strain and axial force of steel beams were presented. The internal force transmission path of composite frame under a penultimate column removal scenario was investigated. The effects of reinforced concrete (RC) slab and weld-bolted connection on the progressive collapse resistance of composite frame were analyzed and discussed. Consequently, the dynamic response prediction and dynamic amplification factor (DAF) were analytically studied by energy balanced method (EBM). Further, the numerical models of composite frames were calibrated by the test results in ABAQUS/Explicit. The results showed that serious torsion of steel beam at directly affected region (DAR) reduced the resistance for the CFST frames with bare steel beam. However, for the CFST frames with composite beam (i.e., with steel beam and RC slab), the RC slab improved the initial stiffness and peak resistance of composite frame and thus mitigated and even prevented the torsion of beam. The composite frames presented an asymmetric failure mode and internal force transmission path under a penultimate column removal scenario, which was different from that under a middle column removal scenario. The composite frames with weld-bolted connection presented a lower resistance than the composite frames with welded connection due to the premature fracture of welded flanges but possessed multi-protection measures to resist progressive collapse due to the intermittent failure modes.

In vitro flow study in a compliant abdominal aorta phantom with a non-Newtonian blood-mimicking fluid

In vitro aortic flow simulators allow studying hemodynamics with a wider range of flow visualization techniques compared to in vivo medical imaging and without the limitations of invasive examinations. This work aims to develop an experimental bench to emulate the pulsatile circulation in a realistic aortic phantom. To mimic the blood shear thinning behavior, a non-Newtonian aqueous solution is prepared with glycerin and xanthan gum polymer. The flow is compared to a reference flow of Newtonian fluid. Particle image velocimetry is carried out to visualize 2D velocity fields in a phantom section. The experimental loop accurately recreates flowrates and pressure conditions and preserves the shear-thinning properties of the non-Newtonian fluid. Velocity profiles, shear rate, and shear stress distribution maps show that the Newtonian fluid tends to dampen the observed velocities. Preferential asymmetrical flow paths are observed in a diameter narrowing region and amplified in the non-Newtonian case. Wall shear stresses are about twice higher in the non-Newtonian case. This study shows new insights on flow patterns, velocity and shear stress distributions compared to rigid and simplified geometry aorta phantom with Newtonian fluid flows studies. The use of a non-Newtonian blood analog shows clear differences in flows compared to the Newtonian one in this compliant patient-specific geometry. The development of this aortic simulator is a promising tool to better analyze and understand aortic hemodynamics and to aid in clinical decision-making.

High-Precision Adjustment of Welding Depth during Laser Micro Welding of Copper Using Superpositioned Spatial and Temporal Power Modulation

For joining metallic materials for battery applications such as copper and stainless steel, laser beam micro welding with beam sources in the near-infrared range has become established in recent years. In laser beam micro welding, spatial power modulation describes the superposition of the linear feed motion with an oscillating motion. This modulation method serves to widen the cross-section of the weld seam as well as to increase the process stability. Temporal power modulation refers to the controlled modulation of the laser power over time during the welding process. In this paper, the superposition of both temporal and spatial power modulation methods is presented, which enables a variable control of the weld penetration depth. Three weld geometries transverse to the feed direction are part of this investigation: the compensation of the weld penetration depth due to the asymmetric path movement during spatial power modulation only, a W-shaped weld profile, and a V-shaped. The weld geometries are investigated by the bed on plate weld tests with CuSn6. Furthermore, the use of combined power modulation for welding tests in butt joint configuration between CuSn6 and stainless steel 1.4301 with different material properties is investigated. The study shows the possibility of precise control of the welding depth by this methodology. Depending on the material combination, the desired regions with maximum and minimum welding depth can be achieved by the control of local and temporal power modulation on the material surface.

Prediction of multiple dry-wet transition pathways with a mesoscale variational approach.

Water fluctuates in a hydrophobic confinement, forming multiple dry and wet hydration states through evaporation and condensation. Transitions between such states are critical to both thermodynamics and kinetics of solute molecular processes, such as protein folding and protein-ligand binding and unbinding. To efficiently predict such dry-wet transition paths, we develop a hybrid approach that combines a variational implicit solvation model, a generalized string method for minimum free-energy paths, and the level-set numerical implementation. This approach is applied to three molecular systems: two hydrophobic plates, a carbon nanotube, and a synthetic host molecule Cucurbit[7]uril. Without an explicit description of individual water molecules, our mesoscale approach effectively captures multiple dry and wet hydration states, multiple dry-wet transition paths, such as those geometrically symmetric and asymmetric paths, and transition states, providing activation energy barriers between different states. Further analysis shows that energy barriers depend on mesoscopic lengths, such as the separation distance between the two plates and the cross section diameter of the nanotube, and that the electrostatic interactions strongly influence the dry-wet transitions. With the inclusion of solute atomic motion, general collective variables as reaction coordinates, and the finite-temperature string method, together with an improved treatment of continuum electrostatics, our approach can be further developed to sample an ensemble of transition paths, providing more accurate predictions of the transition kinetics.

Testing Explicit Mediation Models by Set-Theoretic Causal Complexity

Although the linear mediation model developed by Baron and Kenny (1986) has made great contributions to the study of linear mediation mechanism, it has not substantially contributed to complex causality. Especially, when interactions or interdependent effects of multiple variables may occur in mediation mechanism, linear mediation model only considers individual variable’s separate mediation mechanism. Instead of a linear correlation, the explicit statement of necessity and sufficiency is needed for a falsifiable hypothesis in complex causality. In present article, we indicate the deficiencies of symmetry, simplification, and linearity relationship assumption in linear mediation model, and proposes a complex set-theoretic causality which can deal with asymmetry, complexity, and nonlinearity. Through the explicit discussion of various necessary or sufficient relationships of causal chains in complex causal mediation model, as well as the causal complexity characterized by conjunction and disjunction of multiple conditions, equivalent paths, asymmetric paths, the paper contributes to analyze the causal complexity of mediation mechanism. Instructions are provided on how to test complex causal mediation model.

Weakening-induced Snap Instability as a Novel Reusable Force Protection Mechanism

We present a novel reusable force protection mechanism equipped with snap instability that is induced by weakening boundary conditions. The geometry of the proposed structure comprises one column and two flanges attached to its ends, and it allows the structural end conditions can alter between fixed supports and pinned supports. Switching between the fixed and the pinned supports results in elastic snap instabilities and it enables the structure to possess asymmetric equilibrium paths, whose loading and unloading paths are different. These snap instabilities induce hysteresis in the load-displacement curve, and external energy is converted in form of dynamic motion. After removing the external force, the structure elastically recovers to its initial configuration so that it can repeat the same force protection process. We report a combination of desktop-scale experiments, finite element simulations, and the Elastica analysis to explore the underlying mechanism of the unique structural behavior of the proposed structure. Given that the proposed reusable force protection mechanism exploits elastic instability, our study opens the possibility for practical applications over a wide range of length scales.

Selective Topological Pumping for Robust, Efficient, and Asymmetric Sound Energy Transfer in a Dynamically Coupled Cavity Chain

One-way sound-wave propagation has been a research hotspot in acoustics during the past decade, with the production of acoustic diode, acoustic topological insulator, and parity-time-symmetric acoustic metamaterial. Here, we investigate topological pumping for sound waves in a coupled cavity chain along selective paths driven by dynamic modulation. We first showcase the adiabatic passage of sound energy in a heterostructured Su-Schrieffer-Heeger cavity chain. By solving the Dirac-like governing equation, we calculate the eigenspectrum of this model and prove the existence of a topologically protected interface state and end states. From the eigenspectrum, if no level crossing exists, energy transfer of the sound wave (or acoustic topological pumping) is reversed under adiabatic modulation, leading to the release and return of sound energy for a specific topological state. However, when the level crossing occurs, we find that topological pumping between the interface state and end states can be selectively excited, rendering complete transfer of the sound energy between two topological states. Moreover, topological pumping of sound waves can exist along the asymmetric paths under driven modulation. Our work has promising applications for robust, selective, and efficient sound energy transfer in acoustic network systems.

Numerical simulation of hydraulic fracture propagation in conglomerate reservoirs

Hydraulic fracturing is a necessary production enhancement procedure for low permeable conglomerate reservoirs. To study the hydraulic fracture (HF) propagation mechanism in strong heterogeneous conglomerate reservoirs, a numerical simulation based on the modified global cohesive zone method (CZM) was proposed. Two types of geological conglomerate models were built, and natural fractures were also considered in each model. A comprehensive discussion of the treatment parameters for the fracture geometry and width was also conducted. Numerical simulations suggest that a zig-zig fracture can be formed in all cases, while micro fractures emerge near the main fracture, and the number of micro fractures is larger for the composite gravel model than for the single gravel model. The presence of stiff gravel can affect the fracture propagation path and the associated conductivity and can sometimes result in an asymmetric fracture propagation path. The contribution effect of micro fracture on production might be debatable because of the relatively small fracture width. Four different mechanical behaviors, namely, penetration, deflection, attraction and termination, can be observed. In addition, fracture penetration tends to occur near the wellbore zone, while fracture branching generally occurs at the HF tip. The number of fracture deflection modes dominates the fracture behavior regardless of the distance between the HF and the gravel. The in situ stress condition determines the overall fracture propagation path, but the fracture starts to deviate under a low principal stress difference. An increase in the pump rate controls the fracture length due to a sufficiently large fluid injection volume. The increase in fracturing fluid viscosity does not affect the fracture geometry to a large extent but can heavily arrest fracture closure, thus improving fracture width, which can mitigate the large fracture width reduction along the gravel edge. Compared to the homogeneous rock model, the numerical simulation based on the adopted CZM method can be from a more complex fracture type with the conglomerate model, while numerical results can be validated by the triaxial fracturing simulation in the whole and local areas, which demonstrates the ability to perform a numerical simulation of HF propagation in reservoirs with strong heterogeneity.

Automated Real-Time Evaluation of Condylar Movement in Relation to Three-Dimensional Craniofacial and Temporomandibular Morphometry in Patients with Facial Asymmetry.

The aim of this study was to investigate the correlation between craniofacial morphology, temporomandibular joint (TMJ) characteristics, and condylar functional movement in patients with facial asymmetry using an up-to-date automated real-time jaw-tracking system. A total of 30 patients with mandibular asymmetry and prognathism were included. Three-dimensional (3D) craniofacial and TMJ morphometric variables were analyzed in images captured using cone-beam computed tomography. Three-dimensional condylar movements were recorded during the opening, protrusion, and laterotrusion of the jaw and divided into those for deviated and non-deviated sides. Overall functional and morphometric variables were compared between the sides by a paired t-test. Pearson’s correlation analysis and factor analysis were also performed. As a result, significant differences were found between the sides in morphometric and functional variables. The condylar path length was significantly longer and steeper on the deviated side during protrusion and lateral excursion. TMJ morphometric asymmetry, more so than the craniofacial morphologic asymmetry, seemed to be reflected in the functional asymmetry, representing different correlations between the sides, as supported by factor analysis. This study provides evidence explaining why the asymmetric condylar path remained unchanged even after orthognathic surgery for the correction of craniofacial asymmetry.

Configure the Symmetrical and Asymmetrical Paths of Brand Equity and Relationship of Firm Created Content and User Generated Content as Antecedent

This study aims to investigate in the relationship FCC, UGC, Customer Experience satisfaction towards Brand Equity and Purchase Decision on the subject of e-commerce research in Indonesia (e.g., Lazada, Tokopedia, and Bli-Bli). This study used two research methods: exploratory research (exploratory research) and descriptive research (descriptive analysis). This study's total population was 200 eligible. The collection data with online survey. This study's testing phase is through three phases: first, the reliability of the construct configuration for brand association, brand awareness, brand reputation, and brand performance on brand equity. Second, the relationship that explains the direct and indirect effects of UGC and FCC on brand equity and purchase intention; third, the relationship that demonstrates the impact of variable customer experience satisfaction on brand equity and purchase intention. The result of this study shown from the seven symmetrical paths, the direct relationship is found significant results except for variable relationships such as UGC and FCC on Purchase Intention, which states that there is no significant effect. For example, the indirect relationship between FCC and Purchase Intention mediated by the Brand Equity variable states that there is no positive and significant effect. Except for the relationship between UGC on Purchase Intention mediated by Brand Equity and Brand Equity on Purchase Intention mediated by the Customer Experience Satisfaction variable. Both found that there was a positive and significant relationship.