Minimal Threshold Value Research Articles

Enhancement of the photoinduced birefringence and inverse relaxation of a liquid crystal azopolymer by doping with carbon nanostructures

• Carbon nanotubes can enhance the photoinduced birefringence of azopolymers. • The in situ doping method provides a good polymer-nanotube interaction. • The occurrence of the inverse relaxation depends on the doping method. In this work, the effect of carbon nanotubes (CNTs) and carbon nanofibers (CNFs) on the photoinduced behavior of one side-chain liquid crystal azopolymer is studied. Two distinct methods of doping the azopolymer with CNTs or CNFs are followed: during (in situ method) and after (mixing method) polymerization. Thermotropic studies show that dopants do not have a significant effect on the liquid-crystalline properties of the azopolymer, which develops a smectic A-type phase whose lamellar structure is preserved after cooling to room temperature. On the other hand, the light-induced birefringence of the azopolymer doped by the in situ method (∼ 0.095) is higher than that reached with the corresponding one doped by the mixing method (∼ 0.05). In switch-on/switch-off experiments, both the typical and the inverse relaxation processes of the photoinduced orientation are observed. The inverse relaxation occurs only in the azopolymer doped by the in situ method, which seems to provide a good interaction between the azobenzene units and the nanostructures. In addition, it was found that no minimal threshold value of irradiation dose is required to make the inverse relaxation happen. A model based on non-covalent interactions is proposed to explain the inverse relaxation promoted by nanostructures introduced by the in situ method.

Social Distancing Using YOLOv3 Model

Social isolation has been found to be a successful strategy for preventing the coronavirus from spreading around the world. In order to stop the virus from spreading as possible, the system is designed to analyses social distance by measuring the space between individuals. To lessen the impact of the epidemic, this technology uses input from camera frames to calculate the distance between people. By analyzing a video stream collected from a security camera, this is accomplished. The video is adjusted for a higher perspective and sent in to the prepared item discovery model YOLOv3 as input. The Common Object in Context is used to train the YOLOv3 model (COCO). A previously shot video supported the suggested system. The system's results and consequences demonstrate how to assess the space between different people and decide whether rules are being broken. People are addressed by a red jumping box if the distance is below the minimal threshold value and a green jumping box otherwise. This technique can be improved to recognize social exclusion in a real time setting.

Social Distance Analysing - COVID-19 Using Deep Learning and Computer Vision

In the combat in opposition to the coronavirus, social distancing has tested to be an effective degree to bog down the unfold of the disease. The machine provided is for reading social distancing through calculating the space among humans for you to gradual down the unfold of the virus. This machine makes use of enter from video frames to parent out the space among people to relieve the impact of this pandemic. This is performed through comparing a video feed acquired through a surveillance camera. The video is calibrated into bird’s view and fed as an enter to the YOLOv3 version that is an already educated item detection version. The YOLOv3 version is educated using the Common Object in Context (COCO). The proposed machine turned into corroborated on a pre-filmed video. The outcomes and consequences acquired through the machine display that assessment of the space among more than one people and figuring out if policies are violated or not. If the space is less than the minimal threshold value, the people are represented through a purple bounding box, if not then it's far represented through a inexperienced bounding box. This machine may be similarly advanced to detect social distancing in real-time applications.

Statistically significant words of four Service Menaia of the 11th century

The work deals with experiments on search of keywords in Slavonic Service Menaia of the 11th century by means of three statistic measures — Weirdness, TF*ICTF' and Log-Likelihood. Statistically significant words are found in the lists of 30 the most frequent lemmas of each copy (three other manuscripts play the role of the alternative subcorpus) and their different assessments by the respective measures are shown. The words that are the most significant due to the assessments done by the three measures on the basis of comparison of the ranks of the lemmas ranked by the values of measures are found in each list. Their comparison with the lists of lemmas that are the most significant on the whole for the collections of hymnographic texts of the corpus “Manuscript” helps to find the keywords in each of the manuscripts. Minimal threshold values of the measures are established for revelation of statistically significant linguistic units. Semantic-thematic interpretation of the keywords gives a possibility of seeing their relationship with the main notions of the Christian church and its realization in each manuscript: Menaion of May — defeat of suffering and death, holiness, praise, joy, Menaion of September — purity, God, Menaion of October — truth, peace, Menaion of November — praise, truth, salvation.

A Delay Time Model With Multiple Defect Types and Multiple Inspection Methods

We develop delay time models to determine optimal inspection policies for deteriorating infrastructures. We consider the case where complex infrastructures can fail due to different causes (defects) originating from various environmental or operational conditions, and capture this through modeling the arrival of different types of defects as nonhomogeneous Poisson processes with distinct rates of occurrence of defects. Additionally, we assume at each inspection epoch, there are multiple inspection methods available for use from which one is to be selected for use at that particular epoch. The key contribution that distinguishes our proposed models from previous works on delay time modeling is simultaneously considering multiple defect types and multiple inspection methods. Two mixed-integer nonlinear programming models are introduced to address the problem described above. The first model focuses on determining the optimal inspection policy that maximizes the reliability of the system over its useful life subject to a minimal threshold value of this reliability term. The second model determines the optimal policy that minimizes the system downtime. The two models are solved using a branch-and-cut global optimization approach. Two separate numerical studies are conducted to demonstrate the performance of the models and validate it through benchmarking these results against a prior study in the literature.

Prediction of Maximal Heart Rate in Children and Adolescents.

To identify a method to predict the maximal heart rate (MHR) in children and adolescents, as available prediction equations developed for adults have a low accuracy in children. We hypothesized that MHR may be influenced by resting heart rate, anthropometric factors, or fitness level. Cross-sectional study. Sports medicine center in primary care. Data from 627 treadmill maximal exercise tests performed by 433 pediatric athletes (age 13.7 ± 2.1 years, 70% males) were analyzed. Age, sex, sport type, stature, body mass, BMI, body fat, fitness level, resting, and MHR were recorded. To develop a prediction equation for MHR in youth, using stepwise multivariate linear regression and linear mixed model. To determine correlations between existing prediction equations and pediatric MHR. Observed MHR was 197 ± 8.6 b·min. Regression analysis revealed that resting heart rate, fitness, body mass, and fat percent were predictors of MHR (R = 0.25, P < 0.001), whereas age was not. Resting heart rate explained 15.6% of MHR variance, body mass added 5.7%, fat percent added 2.4%, and fitness added 1.2%. Existing adult equations had low correlations with observed MHR in children and adolescents (r = -0.03-0.34). A new equation to predict MHR in children and adolescents was developed, but was found to have low predictive ability, a finding similar to adult equations applied to children. Considering the narrow range of MHR in youth, we propose using 197 b·min as the mean MHR in children and adolescents, with 180 b·min the minimal threshold value (-2 standard deviations).

Paralog-Specific Functions of RPL7A and RPL7B Mediated by Ribosomal Protein or snoRNA Dosage in Saccharomyces cerevisiae.

Most ribosomal proteins in Saccharomyces cerevisiae are encoded by two paralogs that additively produce the optimal protein level for cell growth. Nonetheless, deleting one paralog of most ribosomal protein gene pairs results in a variety of phenotypes not observed when the other paralog is deleted. To determine whether paralog-specific phenotypes associated with deleting RPL7A or RPL7B stem from distinct functions or different levels of the encoded isoforms, the coding region and introns of one paralog, including an intron-embedded snoRNA (small nucleolar RNA) gene, were exchanged with that of the other paralog. Among mutants harboring a single native or chimeric RPL7 allele, expression from the RPL7A locus exceeded that from the RPL7B locus, and more Rpl7a was expressed from either locus than Rpl7b. Phenotypic differences in tunicamycin sensitivity, ASH1 mRNA localization, and mobility of the Ty1 retrotransposon were strongly correlated with Rpl7 and ribosome levels, but not with the Rpl7 or snoRNA isoform expressed. Although Ty1 RNA is cotranslationally localized, depletion of Rpl7 minimally affected synthesis of Ty1 Gag protein, but strongly influenced Ty1 RNA localization. Unlike the other processes studied, Ty1 cDNA accumulation was influenced by both the level and isoform of Rpl7 or snoRNA expressed. These cellular processes had different minimal threshold values for Rpl7 and ribosome levels, but all were functional when isoforms of either paralog were expressed from the RPL7A locus or both RPL7 loci. This study illustrates the broad range of phenotypes that can result from depleting ribosomes to different levels.

Critical role of ATP-induced ATP release for Ca2+ signaling in nonsensory cell networks of the developing cochlea

Spatially and temporally coordinated variations of the cytosolic free calcium concentration ([Ca2+]c) play a crucial role in a variety of tissues. In the developing sensory epithelium of the mammalian cochlea, elevation of extracellular adenosine trisphosphate concentration ([ATP]e) triggers [Ca2+]c oscillations and propagation of intercellular inositol 1,4,5-trisphosphate (IP3)-dependent Ca2+ waves. What remains uncertain is the relative contribution of gap junction channels and connexin hemichannels to these fundamental mechanisms, defects in which impair hearing acquisition. Another related open question is whether [Ca2+]c oscillations require oscillations of the cytosolic IP3 concentration ([IP3]c) in this system. To address these issues, we performed Ca2+ imaging experiments in the lesser epithelial ridge of the mouse cochlea around postnatal day 5 and constructed a computational model in quantitative adherence to experimental data. Our results indicate that [Ca2+]c oscillations are governed by Hopf-type bifurcations within the experimental range of [ATP]e and do not require [IP3]c oscillations. The model replicates accurately the spatial extent and propagation speed of intercellular Ca2+ waves and predicts that ATP-induced ATP release is the primary mechanism underlying intercellular propagation of Ca2+ signals. The model also uncovers a discontinuous transition from propagating regimes (intercellular Ca2+ wave speed > 11 μm⋅s-1) to propagation failure (speed = 0), which occurs upon lowering the maximal ATP release rate below a minimal threshold value. The approach presented here overcomes major limitations due to lack of specific connexin channel inhibitors and can be extended to other coupled cellular systems.

Ultrafast Population Inversion without the Strong Field Catch: The Parallel Transfer.

Quantum systems with sublevel structures, like molecules, prevent full population inversion from one manifold of sublevels to the other using ultrafast resonant pulses. We explain the mechanism by which this population transfer is blocked. We then develop a novel concept of geometric control, assuming full or partial coherent manipulation within the manifolds, and show that by preparing specific coherent superpositions in the initial manifold, full population inversion or full population blockade, that is, laser transparency, can be achieved. By properly choosing the relative phases of the initial state, one can interfere in the stimulated emission process, changing the pattern of Rabi oscillations so that full population inversion to the excited electronic state can be achieved almost regardless of the pulse intensity after a minimal threshold value. This is the basis of a novel control mechanism, termed parallel transfer.

Colorectal motor and sensory function after hysterectomy

Women may develop constipation after hysterectomy. The pathophysiology and underlying mechanisms are poorly understood. They may originate from either neural damage of rectum and colon or changes in anatomical constellation of the remaining pelvic organs. The aim of this study is to evaluate sensory and motor functions of rectum and colon in women with newly developed constipation after hysterectomy in comparison with women without constipation and healthy controls after hysterectomy . Barostat measurements were performed in posthysterectomy women with constipation (PH-C), without constipation (PH-NC), and healthy controls (n = 10, every group). Outcome measures were rectal and colonic compliance (millilitre per millimetre of mercury), rectocolonic perception in reaction to mechanical distension (millimetre; VAS scores) and rectocolonic reflex (millilitre per millimetre of mercury). No differences in rectal or colonic compliance were observed. Urge perception due to rectal distension increased significantly in controls (from 7 ± 5 to 41 ± 10 mm; p < 0.05) and PH-NC group (from 3 ± 1 to 24 ± 9 mm; p < 0.05), but not in PH-C patients (1 ± 1 to 11 ± 5 mm; ns). In healthy controls and the PN-NC group, respectively, 100 and 70 % of subjects reached the minimal threshold value for urge of 10 mm during the isobaric distension sequence. In the PH-C group, only two subjects (20 %) reached this threshold (p < 0.05). Rectal pain perception, phasic colonic motility and the rectocolonic reflex were intact in all three groups. Colorectal motor and sensory function is generally well preserved in women with constipation after hysterectomy. It is unlikely that the symptom of constipation after hysterectomy has been caused by iatrogenic neuronal damage in these patients.

Application of Weighted Particle Swarm Optimization in Association Rule Mining

Determination of the threshold values of support and confidence, affect the quality of association rule mining up to a great extent. Focus of my study is to apply weighted PSO for evaluating threshold values for support and confidence. The particle swarm optimization algorithm first searches for the optimum fitness value of each particle and then finds corresponding support and confidence as minimal threshold values after the data are transformed into binary values. The proposed method is verified by applying the Food Mart 2000 database of Microsoft SQL Server 2000. I am expecting that the particle swarm optimization algorithm will suggest suitable threshold values and obtain quality rules as per the previous works [1].

P11.22 Time trend of Legionella colonization in the waterline of a hospital of Rome, Italy

P11.22 Time trend of Legionella colonization in the waterline of a hospital of Rome, Italy

Application of particle swarm optimization to association rule mining

In the area of association rule mining, most previous research had focused on improving computational efficiency. However, determination of the threshold values of support and confidence, which seriously affect the quality of association rule mining, is still under investigation. Thus, this study intends to propose a novel algorithm for association rule mining in order to improve computational efficiency as well as to automatically determine suitable threshold values. The particle swarm optimization algorithm first searches for the optimum fitness value of each particle and then finds corresponding support and confidence as minimal threshold values after the data are transformed into binary values. The proposed method is verified by applying the FoodMart2000 database of Microsoft SQL Server 2000 and compared with a genetic algorithm. The results indicate that the particle swarm optimization algorithm really can suggest suitable threshold values and obtain quality rules. In addition, a real-world stock market database is employed to mine association rules to measure investment behavior and stock category purchasing. The computational results are also very promising.

Vymezení a vyhodnocení agresivity centrálních bank

This paper examines definitions and assessments of central bank aggressiveness. It shows theoretical reasons why there is certain minimal threshold value if CB wants to stabilize price level and on the other hand, why excessive reactions are suboptimal. The empirical part suggests that aggressiveness could be measured by defining certain indicators, based on variability of interest rates, inflation and output gap. The results are reported for countries with independent monetary policy as well as for countries in the eurozone, which has handed their monetary independency to ECB.

Short Term Relaxation Modeling of Valve Stem Packings

The long term tightness performance of stuffing-box packings, used in valves, is conditioned by the capacity of its sealing material to maintain a contact pressure to a predetermined minimal threshold value. Due to the creep, this contact pressure decreases with time depending on the creep properties and the stiffness of the housing. Assessing relaxation is a key parameter in determining the tightness performance of a valve stem packing over time. An analytical model based on the packing viscoelastic behavior is developed to assess the contact pressures between the packing material and the stem and the housing and their variation with time. In parallel, an axisymmetric 2D finite element model was build to validate and support the analytical model. The valve stem packing relaxation performance is an important design parameter to consider when selecting compression packings.

Acetylcholinesterase activity in Gammarus fossarum (Crustacea Amphipoda) : Intrinsic variability, reference levels, and a reliable tool for field surveys

The appropriate use of an enzyme activity as a biomarker requires good knowledge of its basal level and its natural variability related to intrinsic biotic and environmental abiotic factors. In view of using whole-body acetylcholinesterase (AChE) activity in Gammarus fossarum as a reliable biomarker of exposure to anti-cholinesterase agents in aquatic ecosystems, (i) the effects of the main biotic (sex, reproductive status, and weight) and abiotic (water temperature) factors on the basal activity level of this enzyme were measured in the laboratory and (ii) the spatio-temporal variability of basal enzyme activity was followed in wild populations over a 1-year period. The results show no direct effect of sex. However, significant differences in AChE activity were observed between females depending on gonadal and embryonic development. A strong negative correlation between the AChE activity levels and organism body weight was observed. Indeed, AChE activity decreases drastically during the early life stages and tends to stabilise in larger individuals. These reports led us to select a standard organism (male; weight range, 15–20 mg) to minimise inter-individual variability. No effect of temperature on basal AChE activity was observed in the laboratory for the tested range (6–24 °C). Similarly, no spatio-temporal change relative to season or the physico-chemical characteristics of the water (such as conductivity and temperature) was recorded during the field survey. On the basis of field-collected data, we defined the standard organism having a reference activity level with minimal and maximal threshold values. Finally, the value of AChE activity normalisation by protein contents is discussed.

Threshold of a Symmetrically Pumped Distributed Feedback Fiber Laser With a Variable Phase Shift

In this paper, we study, both theoretically and experimentally, the threshold characteristics of a distributed feedback fiber laser that depend on the value of a phase shift introduced into the fiber Bragg grating structure. We show that as the phase shift possesses a noticeable birefringence, the laser oscillates at any phase shift value. We also reveal that the laser threshold is different for the cavity eigen polarizations and depends on the phase shift value. We derive a simple analytical formula to calculate the laser threshold in the case of pi phase shift; this formula can be utilized to estimate a minimal threshold value for the laser with certain active fiber and Bragg grating parameters. The developed theory allows us to fairly model the experimentally measured dependence of the laser threshold on induced phase shift value.

Ionization-overheating instability threshold in the electrodeless microwave discharge plasma

Experiments with a pulsed freely localized electrodeless microwave discharge in air under a pressure corresponding to the ascending branch of the pressure dependence of the breakdown field are described. The discharge is initiated in a focused quasi-optical electromagnetic beam. The minimal threshold values of the electromagnetic field (for which a brighter plasma channel extended along the field is formed in the initially spatially homogeneous diffuse discharge plasma) are determined by varying air pressure for several fixed values of this field in the focal region of the beam. In accordance with the prevailing theory, this phenomenon is interpreted as the result of evolution of ionization-overheating instability in the microwave discharge plasma.

Endogenous Protease Activation of ENaC

Endogenous serine proteases have been reported to control the reabsorption of Na+ by kidney- and lung-derived epithelial cells via stimulation of electrogenic Na+ transport mediated by the epithelial Na+ channel (ENaC). In this study we investigated the effects of aprotinin on ENaC single channel properties using transepithelial fluctuation analysis in the amphibian kidney epithelium, A6. Aprotinin caused a time- and concentration-dependent inhibition (84 ± 10.5%) in the amiloride-sensitive sodium transport (INa) with a time constant of 18 min and half maximal inhibition constant of 1 μM. Analysis of amiloride analogue blocker–induced fluctuations in INa showed linear rate–concentration plots with identical blocker on and off rates in control and aprotinin-inhibited conditions. Verification of open-block kinetics allowed for the use of a pulse protocol method (Helman, S.I., X. Liu, K. Baldwin, B.L. Blazer-Yost, and W.J. Els. 1998. Am. J. Physiol. 274:C947–C957) to study the same cells under different conditions as well as the reversibility of the aprotinin effect on single channel properties. Aprotinin caused reversible changes in all three single channel properties but only the change in the number of open channels was consistent with the inhibition of INa. A 50% decrease in INa was accompanied by 50% increases in the single channel current and open probability but an 80% decrease in the number of open channels. Washout of aprotinin led to a time-dependent restoration of INa as well as the single channel properties to the control, pre-aprotinin, values. We conclude that protease regulation of INa is mediated by changes in the number of open channels in the apical membrane. The increase in the single channel current caused by protease inhibition can be explained by a hyperpolarization of the apical membrane potential as active Na+ channels are retrieved. The paradoxical increase in channel open probability caused by protease inhibition will require further investigation but does suggest a potential compensatory regulatory mechanism to maintain INa at some minimal threshold value.

The repeatability of corticomotor threshold measurements

Threshold (Th) is a neurophysiological parameter frequently used in TMS studies. The present study was designed to investigate the repeatability of the Th measurements by reexamining healthy subjects over various time points. Overall, 82 subjects (median age: 19 years, range: 12–65) entered the study. Following a baseline examination, there were six retest sessions: S0 ( n = 8 hemispheres reexamined, mean interval x = 19 min), S1 ( n = 34 hemispheres reexamined, mean interval x = 4 days), S2 ( n = 32 hemispheres, x = 29 days), S3 ( n = 30 hemispheres, x = 106 days), S4 ( n = 30 hemispheres, x = 183 days) and S5 ( n = 30 hemispheres, x = 1867 days). Stimulation was performed with a figure of eight coil and Th was defined at 1% steps. At baseline, controls had an MT of 41.1 ± 8. Mean difference of MT from baseline was 0.62 on S0 (95% confidence interval (CI) of the difference: –1.04 to +2.29), 0.13 on S1 (95% CI: –1.2 to +1.5), –0.03 on S2 (95% CI: –1.1 to +1.06), –2.07 on S3 (95% CI: –4.33 to +0.19), 0.15 on S4 (95% CI: –0.98 to +1.28) and 0.87 on S5 (95% CI: –0.49 to +2.23). None of these differences were statistically significant (repeated measures ANOVA, P > 0.05). The upper limit of MT difference that an individual subject might have with a probability of 95% (measurement error) was 8. The repeatability of the method was found to be independent from the age of the subjects, the magnitude of threshold or the test–retest interval. The topography of corticomotor threshold was also investigated. Minimal threshold values were obtained from a restricted area of scalp sites that always included the fixed stimulation point of the current protocol. Therefore, using a fixed stimulation point is an adequate technique for measuring threshold. In conclusion, threshold is a stable parameter on an individual and group basis. These data quantify the repeatability of the method and may prove useful in the interpretation of findings during longitudinal studies.