Firing Strategies Research Articles

Human sympathetic neuronal discharge and recruitment patterns regulate neuropeptide Y bioavailability.

What is the purpose of sympathetic neuronal action potential (AP) discharge and recruitment patterns for human vascular regulation? This study tested the hypothesis that sympathetic neuronal discharge and recruitment patterns regulate neuropeptide Y (NPY) bioavailability. We used microneurography to record muscle sympathetic nerve activity (MSNA) and a continuous wavelet transform to detect sympathetic APs during a baseline condition and intravenous dexmedetomidine infusion (α2-adrenergic agonist, 10 min loading infusion of 0.225 µg kg-1; maintenance infusion of 0.1-0.5 µg kg h-1) in six healthy individuals (5 females, 27 ± 6 years). Arterial blood samples provided NPY (enzyme-linked immunosorbent assay) and norepinephrine (Liquid Chromatography Tandem Mass Spectrometry) levels during baseline and the dexmedetomidine maintenance infusion. Linear mixed model regressions assessed the relationships between AP discharge, recruitment, and neurotransmitter levels. Across baseline and the dexmedetomidine condition, NPY levels were positively related to mean arterial pressure (β = 1.63 [0.34], P = 0.002), total AP clusters (β = 0.90 [0.22], P = 0.005), and AP frequency (β = 0.11 [0.03], P = 0.003). Norepinephrine levels were not related to mean arterial pressure (β = 0.03 [0.02], P = 0.133) but were positively related to total AP clusters (β = 19.50 [7.07], P = 0.030) and AP frequency (β = 2.66 [0.81], P = 0.014). These data suggest that sympathetic neuronal discharge and recruitment patterns regulate NPY and norepinephrine bioavailability in healthy adults. As such, sympathetic neuronal firing strategies are important for human vascular regulation.

Characterising sex-related differences in lower- and higher-threshold motor unit behaviour through high-density surface electromyography.

Emerging questions in neuromuscular physiology revolve around whether males and females share similar neural control in diverse tasks across a broad range of intensities. In order to explore these features, high-density electromyography was used to record the myoelectrical activity of biceps brachii during trapezoidal isometric contractions at 35% and 70% of maximal voluntary force (MVF) on 11 male and 13 female participants. Identified motor units were then classified as lower-threshold (recruited at ≤30%MVF) and higher-threshold (recruited at>30%MVF). The discharge rate, interspike interval variability, recruitment and derecruitment thresholds, and estimates of neural drive to motor neurons were assessed. Female lower-threshold motor units showed higher neural drive (P<0.001), accompanied by higher discharge rate at recruitment (P=0.006), plateau (P=0.001) and derecruitment (P=0.001). On the other hand, male higher-threshold motor units showed greater neural drive (P=0.04), accompanied by higher discharge rate at recruitment (P=0.005), plateau (P=0.04) and derecruitment (P=0.01). Motor unit discharge rate normalised by the recruitment threshold was significantly higher in female lower-threshold motor units (P<0.001), while no differences were observed in higher-threshold motor units. Recruitment and derecruitment thresholds are higher in males across all intensities (P<0.01). However, males and females have similar activation and deactivation strategies, as evidenced by similar recruitment-to-derecruitment ratios (P>0.05). This study encompasses a broad intensity range to analyse motor unit sex-related differences, highlighting higher neural drive and discharge rates in female lower-threshold motor units, elevated recruitment and derecruitment thresholds in males, and convergences in activation and deactivation strategies. HIGHLIGHTS: What is the central question of the study? Do male and female motor units behave similarly in low- and high-intensity contractions? What is the main finding and its importance? Female motor units show higher discharge rates in low-intensity tasks and lower discharge rates in high-intensity tasks, with no differences in recruitment behaviour. A broader inter-spike interval variability was also observed in females. These findings underline that there are sex-specific differences concern the firing strategies based on task intensity.

Effect of firing time and wall thickness on the biaxial flexural strength of 3D-printed zirconia

ObjectivesTo evaluate the effect of accelerated firing on 3D-printed zirconia. MethodsTo check if formulae provided by ISO 6872 can be extended to thin samples, finite element analyses were carried out in advance of fabricating 3-mol% yttria-stabilized tetragonal zirconia polycrystal discs by milling and by 3D-printing. Four groups (n = 38 each) of 3D-printed specimens were produced with two nominal thicknesses (0.6 mm and 1.2 mm) and two firing strategies (long: 51 h, accelerated: 14.5 h). In the milled group (thickness 1.2 mm, n = 30), a standard firing program (9.8 h) was selected. Biaxial flexural strength tests were applied and mean strength, characteristic strength, and Weibull modulus were calculated for each group. Differences were analyzed using Welch ANOVA and Dunnett-T3 post-hoc tests. ResultsMaximum tensile stresses occurring during biaxial strength testing can be calculated according to ISO 6872 for thin samples with b > 0.3 mm. Variability of measured strengths values was smaller for milled zirconia compared with 3D-printed zirconia. The 1.2-mm-thick 3D-printed samples had significantly decreased strength after accelerated firing than after long firing. However, for the 0.6-mm-thick samples, comparable mean biaxial strength values of about 1000 MPa were measured for both firing protocols. SignificanceAt the moment, long fabrication time for zirconia restorations is a major drawback of 3D-printing when compared with milling technology. This investigation showed that the strength of 0.6-mm-thick zirconia discs fabricated by 3D-printing was not impaired by accelerated firing. Thus, overnight firing of thin-walled 3D-printed zirconia restorations could be possible.

Математическая модель для имитационной реализации функционирования системы противовоздушной обороны соединения надводных кораблей

The article considers the stages of the logical-time cyclogram of detection and maintenance of groups of controlled objects by means of the air defense system of a naval surface force. An algorithm for forming arrays of detected objects is implemented, taking into account the impulse volume, the coverage sector to accompany all detected objects and other configuration factors, considering probabilistic estimates of the detection of controlled objects. A mathematical model of the functioning of the naval surface force air defense system has been created, taking into account various parameters of active means affecting the groups of controlled objects, as well as taking into account firing strategies in the presence of network-centric control of the order of controlled objects. An algorithm for evaluating the results of fire counteraction of a network-centric group of controlled objects on the part of the air defense system of a naval surface force has been considered. A variant of the simulation implementation of the logical-time cyclogram of the operation of air defense system fire channels has been developed, and examples of the implementation of a logical-time cyclogram for an arbitrary composition of the air defense system are given, taking into account the strategic actions of active means of a naval surface force. Additional conditions for embedding the developed version of the algorithm of the air defense system logical-time cyclogram into the system for simulating the conflict interaction of systems are listed

Model-Based Analysis of Muscle Strength and EMG-Force Relation with respect to Different Patterns of Motor Unit Loss

This study presents a model-based sensitivity analysis of the strength of voluntary muscle contraction with respect to different patterns of motor unit loss. A motor unit pool model was implemented including simulation of a motor neuron pool, muscle force, and surface electromyogram (EMG) signals. Three different patterns of motor unit loss were simulated, including (1) motor unit loss restricted to the largest ones, (2) motor unit loss restricted to the smallest ones, and (3) motor unit loss without size restriction. The model outputs including muscle force amplitude, variability, and the resultant EMG-force relation were quantified under two different motor neuron firing strategies. It was found that motor unit loss restricted to the largest ones had the most dominant impact on muscle strength and significantly changed the EMG-force relation, while loss restricted to the smallest motor units had a pronounced effect on force variability. These findings provide valuable insight toward our understanding of the neurophysiological mechanisms underlying experimental observations of muscle strength, force control, and EMG-force relation in both normal and pathological conditions.

Concurrently controlled grammars

This paper introduces a new variant of Petri net controlled grammars, namely a concurrently controlled grammar, where the control over the application of the productions of a grammar is realized by a Petri net with different parallel firing strategies. The generative capacity of these grammars is investigated with respect to transition labeling strategies, definitions of final marking sets and parallel transition firing modes. It is shown that the labeling strategies do not effect the computational power whereas the maximal firing modes increase the power of concurrently controlled grammars with erasing rules up to Turing machines.

Times They Were a-Changing

Locally produced pottery underwent significant changes in Iron Age Mallorca, changes that can be traced in a range of aspects of the chaîne opératoire, including raw materials, paste recipes, firing strategies and potters’ skills. This study explores technological changes in pottery production by combining a social understanding of technology and a contextual approach to historical processes involving the Balearic Islands and their indigenous inhabitants. Changes in pottery manufacturing techniques and materials are first investigated through archaeometric analysis of a large ceramic assemblage from three sites in southwest Mallorca. Secondly, the possible implications of culture contact between indigenous communities and foreign visitors for local pottery production are examined. Finally, the changes in local pottery and new ways of organising production are considered in the social context of Late Iron Age indigenous communities on the Balearic Islands. This multiple perspective relies on both external and internal factors for interpretation, and suggests diverse causes and consequences for technological change; it also highlights questions about the social organisation of production, information and knowledge transfer, learning contexts and the social value of indigenous pottery.

Context-Free Petri Net Controlled Grammars under Parallel Firing Strategy

Petri nets are becoming one of the most important mathematical tools in Computer Science. In this paper we propose a new firing strategy in Petri Nets called a parallel firing strategy and study some mathematical properties of concurrent grammars which are controlled by Petri nets under parallel firing strategies. We propose some modes on this strategy and a notion of concurrent context-free grammar which is a similar to the context-free Petri nets under parallel firing strategy, where parallel firing modes of context-free Petri nets were converted to rule applications in context-free grammars. Moreover, we investigate some their properties.

Recurrence quantification analysis of surface electromyogram supports alterations in motor unit recruitment strategies by anodal transcranial direct current stimulation.

Recent evidence indicates that anodal transcranial direct current stimulation (tDCS) can selectively alter the EMG/force relationship of agonist arm muscles; however, the mechanisms mediating those changes are less clear. The purpose of this study was to evaluate the effect of anodal tDCS on motor unit synchronization by using a sophisticated non-linear EMG analysis called recurrence quantification analysis (RQA). Surface EMG signals were collected from the biceps brachii muscle of eighteen healthy young adults (9 tDCS and 9 control) at various force levels (12.5%, 25%, 37.5%, and 50% maximum) before and after the application of anodal tDCS over the primary motor cortex. RQA was employed to quantify the changes in percentage of determinism (% DET) and laminarity (% LAM) of the surface EMG signals, which are surrogate measures of motor unit synchronization. RQA analyses indicated that the changes in % DET and % LAM scores were significantly higher in the tDCS group than in the control group (p < 0.05) and this effect was particularly pronounced at higher force levels. The results of this study provide novel evidence supporting that anodal tDCS significantly alters motor unit firing strategies (i.e., the degree of synchronization) of the biceps brachii muscle.

Middle Palaeolithic firing strategies and exceptional thermal blast during OIS5 at Abri du Maras (Ardèche, France)

Middle Palaeolithic firing strategies and exceptional thermal blast during OIS5 at Abri du Maras (Ardèche, France)

Multiple equilibria in a firing game with impartial justice

In this paper, we argue that firms' firing strategies and the judicial strategy of dismissed employees depend to a large extent on labor judges' ability to shed light on the various cases. The model is cast as a sequential game with imperfect information featuring firms, employees and labor judges. The judges' error margin increases with the congestion of the judicial system. The game presents multiple equilibria which differ in the frequency of good workers fired for unfair motives and the frequency of unreliable workers who abusively sue firms for unfair dismissal. The probability that the judge sits with the employee appears to be positively related to the ratio between the severance payment for economic dismissal and the company fine for abusive dismissal.

Hiring Strategies and the Evolution of Honesty

The evolution of honesty norms in a society is studied. Our approach is based on the hypothesis that hiring or firing strategies chosen by firms may affect honesty: if it becomes common knowledge in the society that being honest is better for workers than cheating employers, then the share of opportunists gradually go down. It is shown that different hiring strategies are rational under different honesty standards. If honesty is not a prevailing social norm and volumes of appropriated rent may by high enough, then firms are better off to stimulate honest behavior by increasing wages. For a relatively honest society, firing cheaters is the best strategy. If honesty standards are intermediate or citizens are too impatient, ignorance of cheating may be rational. Therefore one observes three possible patterns of honesty evolution: honesty norms may either descend to critically low level or stabilize at some point or rise and fall cyclically. We prove that honesty standard rises as losses from dishonest behavior or hiring cost increase, honesty standard falls as rent appropriation opportunities expand or citizens get more impatient, and high expectations of economic growth promote honesty.

An Examination of Some Artillery Firing Strategies to Maximize Coverage of a Circular Target Area

An Examination of Some Artillery Firing Strategies to Maximize Coverage of a Circular Target Area

A Postcolonial Moment in Science Studies

I juxtapose a story of Aboriginal landowners demonstrating their firing strategies with a story of environmental scientists elaborating their regimes of burning. The firings are profoundly different, and maintaining those differences is crucial for both Aborigines and scientists. Yet it is also important for both these groups to develop links between the forms of firing. I argue for understanding both firing regimes as expressions of collective memory which embed evaluative witness. This sameness enables modest yet sufficient connection. Acknowledging this translating form of ‘sameness’ would have scientists and Aborigines engaging an alternative form of generalizing, promoting a transformative moment in both knowledge traditions. This alternative form of generalizing embeds a politics different from the politics embedded in orthodox scientific and Yolngu forms of generalizing. I claim the tension made in articulating these alternative forms of generalizing as a ‘postcolonial moment’.

Preparation and properties of sol-gel derived PZT thin films for decoupling capacitor applications

Abstract The use of ceramic thin films as decoupling capacitors offers the possibility of capacitor integration within the integrated circuit (IC) package, and potentially, directly onto the IC itself. Since these configurations minimize series inductance, higher operational speeds are possible. In the present study we have investigated the dielectric and leakage characteristics of sol-gel PZT films. For compositions near the morphotropic phase boundary, dielectric constants of 1000, and loss tangents of about 0.02, were observed. The current-voltage behavior of the capacitors was characterized by a non-linear response, and significant asymmetry in both the leakage and breakdown characteristics as a function of bias sign was observed. Breakdown fields for PZT 53/47 thin films were typically ∼800 kV/cm at 25°C. We have also studied the effects of La and Nb dopant additions and alternate firing strategies on film leakage characteristics. Donor doping at 2–5 mol% lowered leakage currents by a factor of 103 F...

Copper Interactions in Thick Film Multilayer Ceramics: Dielectric Blushing and Performance

AbstractAs the popularity of copper metallizations grows in ceramic-based electronic applications, an understanding of copper-ceramic interactions during firing assumes greater technological importance. Copper metallizations often interact with thick film microcircuit dielectrics during the firing of multilayer interconnects to yield rosy discoloration, or so-called blushing or staining of this insulating ceramic. In the conventional filled-glass dielectrics studied here, blushing is concentrated at special interfaces over Cu conductors where submicron Cu precipitates are localized. Several firing strategies which improve binder burnout can be employed using standard belt furnaces to depress, if not prevent, this precipitation. A multistage blushing mechanism is proposed that is dominated by the reduction of Cu ions in the ceramic by carbonaceous products formed when firing dielectric compositions under non-oxidizing conditions. Dielectric glass composition also plays an important role with respect to solid state Cu ion interdiffusion. Theoretical and experimental analyses show that materials interactions responsible for blushing in conventionally-processed CMS (copper multilayer system) microcircuits degrade neither dielectric performance nor reliability. Microcircuit dielectrics metallized by Cu compare favorably to noble metal systems including gold, an accepted military standard. CMS dielectrics exhibit high activation barriers for ionic conductivity, and an absence of shorting due to solid state diffusion during high temperature/ high bias testing.