Signal-induced noise is observed in Hamamatsu R11265 Multianode Photomultiplier Tubes, manifesting up to several microseconds after the single photoelectron response signal and localised in specific ...anodes. The mean number of noise pulses varies between devices, and shows significant dependence on the applied high-voltage. The characterisation of this noise and the mitigation strategies to perform optimal single-photon counting at 40 MHz, as required by the LHCb Ring-Imaging Cherenkov detectors, are reported.
The performance of the ring-imaging Cherenkov detectors at the LHCb experiment is determined during the LHC Run 2 period between 2015 and 2018. The stability of the Cherenkov angle resolution and ...number of detected photons with time and running conditions is measured. The particle identification performance is evaluated with data and found to satisfy the requirements of the physics programme.
In models with large extra dimensions, “miniature” black holes (BHs) might be produced in high-energy proton–proton collisions at the Large Hadron Collider (LHC). In the semi-classical regime, those ...BHs thermally decay, giving rise to large-multiplicity final states with jets and leptons. On the other hand, similar final states are also expected in the production of electroweak sphaleron/instanton-induced processes. We investigate whether one can discriminate these scenarios when BH or sphaleron-like events are observed in the LHC using machine learning (ML) methods. Classification among several BH scenarios with different numbers of extra dimensions and the minimal BH masses is also examined. In this study we consider three ML models: XGBoost algorithms with (1) high- and (2) low-level inputs, and (3) a Residual Convolutional Neural Network. In the latter case, the low-level detector information is converted into an input format of three-layer binned event images, where the value of each bin corresponds to the energy deposited in various detector subsystems. We demonstrate that only a small number of detected events are sufficient to effectively discriminate between the sphaleron and BH processes. Separation between BH scenarios with different minimal masses is possible with an order of 10 events passing the preselection. A sufficient number of events could be observed in combined Run-2 and -3 data, if the production cross section is not much smaller than the present limit
∼
0.1
fb. We find, however, that a large number of events is needed to discriminate between BH hypotheses with the same minimal BH mass, but different numbers of extra dimensions.
Six polybrominated diphenyl ethers (PBDEs), one hexabromobiphenyl polybrominated biphenyl (PBB), and one hexachlorobiphenyl polychlorinated biphenyl (PCB) were measured in 40 human serum pools ...collected in the southeastern United States during 1985 through 2002 and in Seattle, Washington, for 1999 through 2002. The concentrations of most of the PBDEs, which are commercially used as flame retardants in common household and commercial applications, had significant positive correlations with time of sample collection, showing that the concentrations of these compounds are increasing in serum collected in the United States. In contrast, PCB and PBB levels were negatively correlated with sample collection year, indicating that the levels of these compounds have been decreasing since their phaseout in the 1970s.
Six polybrominated diphenyl ethers (PBDEs), one hexabromobiphenyl polybrominated biphenyl (PBB), and one hexachlorobiphenyl polychlorinated biphenyl (PCB) were measured in 40 human serum pools ...collected in the southeastern United States during 1985 through 2002 and in Seattle, Washington, for 1999 through 2002. The concentrations of most of the PBDEs, which are commercially used as flame retardants in common household and commercial applications, had significant positive correlations with time of sample collection, showing that the concentrations of these compounds are increasing in serum collected in the United States. In contrast, PCB and PBB levels were negatively correlated with sample collection year, indicating that the levels of these compounds have been decreasing since their phaseout in the 1970s.
The climate of the workplace, as well as the issues of relations and ties in the professional environment have long aroused considerable interest among psychologists and management practitioners. The ...organizational climate, which is defined as a set of beliefs about the organization, its relations, the atmosphere of the workplace, circulation of communication, development opportunities, etc., has often been associated with well-being and job satisfaction. Performing work related to numerous stress factors and difficult situations may significantly affect how both the professional environment and employees’ well-being are perceived. Many empirical studies concerning work psychology and organization, including the works of Rosenstiel and Boegel, Gonzales-Roma, Peiro, Schneider and Earhart underline the importance of the organization climate in the construction of efficient and effectively functioning organizations. One of its important aspects is the level of social relationships and cooperation within an organization. Ties in the workplace are defined as the quality and depth of relations between members of an organization. Studies presented in this paper are of an exploratory nature due to the sector specificity, i.e., aviation and provision of services related to ground control operations. The aim of the empirical research presented herein is to verify the assumption about mutual relations between such variables as the perceived climate of the workplace and interpersonal bonds, as well as experiencing negative emotional states, such as the sense of danger and stress. The psychological literature suggests that low evaluation of the organizational climate parameters should be related to worse, more negative evaluation of the workplace and that the dissatisfaction within the scope of ties and relations with employees affects the perception of stress and threat. In the course of the study, 326 persons working at Pyrzowice and Szymany (Poland) and Kosice (Slovakia) have been examined. Polish employees dominated in this group (250 persons). The remaining group was constituted of individuals working at the Kosice (Slovakia) airport. The respondents represent a specific professional group. The authors tried to learn the specificity of the stress and threat experiencing process due to organizational variables—such as aspects related to evaluation of the workplace and the feeling of ties. To achieve this goal, in the course of statistical analyses, models were built to predict the sense of danger and stress among the surveyed population. A hierarchical regression analysis was carried out in order to determine which of the variables allow predicting the sense of danger and stress in the examined occupational group. The results showed that the higher sense of threat was predicted by the less positive views about the workload, the social support and by the higher ratings of ties in the workplace. In this model, the statistically significant predictors of the sense of threat were the perception of workload (β = − 0.184; s.e. = 0.29; t = −3.297; p < 0.001), the social support (β = − 0.272; s.e. = 0.52; t = −3.916; p < 0.001) and ties in the workplace (β = 0.115; s.e. = 0.51; t = 2.162; p = 0.031). Additionally, the higher level of sense of stress was predicted by the less positive views about the workload, fair play and by the higher sense of threat. The final model explained 12% of all variability regarding the sense of stress (R2 = 0.115; F 8, 317 = 5.122; p < 0.001). In this model, the statistically significant predictors of the sense of stress were the workload (β = − 0.120; s.e. = 0.11; t = −2.079; p = 0.038), sense of justice (β = 0.160; s.e. = 0.20; t = 1.965; p < 0.001) and the sense of threat (β = 0.219; s.e. = 0.02; t = 3.859; p < 0.001). The interest in employees from the aviation sector stems from the lack of empirical data on how people working in this industry function psychologically. This branch of industry is currently developing extremely dynamically and is expected to evolve even more in the wake of the industrial revolution 4.0. Work in the field of modern industry 4.0 forces the employees to acquire many important competencies related to managing new, automated working conditions. As suggested by some authors (Popkova, 2019; Neufeind, 2018), in the light of the 4.0 revolution, one must assume that both the requirements of the work environment and reactions and behavior of employees will differ from the more typical and stable organizational conditions. Meanwhile, in the light of automation and specificity of the industry in question, not much attention is paid to human resources, who—while cooperating in various teams (organic and inorganic)—experience various challenges, as well as difficulties resulting from their professional work.
Nowadays, taking into account the multidimensionality of the external environment and necessity of the sustainable development of human resources, organizations are obliged to take more care of the ...psychological resources of their employees, e.g., positive orientation, ego resilience, and emotional stability. Such resources affect how we cope with stress and a sense of threat. The authors of this paper focus on people employed in the aviation sector, who work in the hard-to-cope environment of full automation, demanding working conditions and numerous stressors. The presented study fills a gap in the research on the psychological characteristics of the aviation sector. Moreover, a sense of stress/threat is described in the context of the high specificity of employees representing the 4.0 sector. Therefore, it provides additional insights into the psychological functioning of the employees in the aviation sector. The results show that both positive orientation and ego resilience might be seen as protective factors against a sense of threat and stress, while a type D personality is a risk factor of a higher level of those psychological states. The novelty of the presented research concerns a better understanding of the sense of stress/threat experienced by the employees in this sector, as well as verifying the relationships between psychological variables described in the literature as personal resources.
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