Bulletin of NTU "KhPI". Series: Problems of Electrical Machines and Apparatus Perfection. The Theory and Practice / Вісник Національного технічного університету "ХПІ". Серія: Проблеми удосконалювання електричних машин і апаратів. Теорія і практика
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How Does The COVID-19 Pandemic Impact on Population Mental Health? A Network Analysis of COVID Influences On Depression, Anxiety and Traumatic Stress in the UK Population
No full textBackground. The COVID-19 emergency has led to numerous attempts to assess the impact of the pandemic on population mental health. Findings indicate an increase in depression and anxiety but have been limited by the lack of specificity about which aspects of the pandemic (e.g. viral exposure or economic threats) have led to adverse mental health outcomes.
Methods. Network analyses were conducted on data from wave 1 (N = 2025 recruited March 23rd – March 28th 2020) and wave 2 (N = 1406 recontacts, 22 April – 1 May 2020) of the COVID-19 Psychological Research Consortium Study, an online longitudinal survey of a representative sample of the UK adult population. Our models included depression (PHQ-9), generalised anxiety (GAD-7) and trauma symptoms (ITQ) and also measures of Covid-specific anxiety, exposure to the virus in self and close others as well as economic loss due to the pandemic.
Results. A mixed graphical model at wave 1 indicated that economic adversity impacted on anxiety symptoms via specific anxiety about the pandemic. There was no association between viral exposure and symptoms. Ising network models using clinical cut-offs for symptom scores at each wave yielded similar findings with the exception of a modest effect of viral exposure on trauma symptoms at wave 1 only. Anxiety and depression symptoms formed separate clusters at wave 1 but not wave 2.
Conclusions. The psychological impact of the pandemic evolved in the early phase of lockdown. Adverse psychiatric outcomes were particularly associated with exposure to the economic consequences of the pandemic
Compassionate Embodied Virtual Experience Increases the Adherence to Meditation Practice
No full textVirtual Reality (VR) could be useful to overcome imagery and somatosensory difficulties of compassion-based meditations given that it helps generate empathy by facilitating the possibility of putting oneself into the mind of others. Thus, the aim of this study was to evaluate the effectiveness of an embodied-VR system in generating a compassionate response and increasing the quality and adherence to meditation practice. Health professionals or healthcare students (n = 41) were randomly assigned to a regular audio guided meditation or to a meditation supported by an embodied- VR system, “The machine to be another”. In both conditions, there was an initial in-person session and two weeks of meditation practice at home. An implicit measure was used to measure prosocial behavior, and self-report questionnaires were administered to assess compassion related constructs, quality of meditation, and frequency of meditation. Results revealed that participants from the embodied-
VR condition meditated for double the amount of time at home than participants who only listened to the usual guided meditation. However, there were no significant differences in the overall quality of at-home meditation. In conclusion, this study confirms that embodied-VR systems are useful for increasing adherence to meditation practice
Market cognition: How exchange norms alter social experience
No full textMarket exchange and the ideologies that accompany it pervade human social interaction. How does this affect people’s beliefs about themselves, each other, and human nature? Here we describe market cognition (MC) as social inferences and behaviors that are intensified by market contexts. We focus on prosociality, and two countervailing ways MC can affect it. On the one hand, marketplaces incentivize individuals to behave prosocially in order to be chosen as exchange partners—generalizing cooperation and trust beyond group boundaries. On the other hand, markets encourage a view of people as self-interested, and can thus taint people’s interpretation of prosocial actions and erode more communal forms of cooperation. We close by considering how MCs can become self-fulfilling, altering relationships, communities, and cultural norms
Target–background segregation in a spatial interference paradigm reveals shared and specific attentional mechanisms triggered by gaze and arrows
No full textRecent research has found that eye gaze and arrows yield opposite congruency effects in a spatial interference paradigm, arrows eliciting faster responses when their direction is congruent with their position (standard congruency effect), and gaze producing faster reaction times for incongruent conditions (reversed congruency effect). In addition, we observed by serendipity in a previous study that the standard effect with arrows was reduced when the target appeared within a complex background, presumably because of hindered figure–ground segregation. Under the same conditions, the reversed effect with gaze became more negative. To explain our previous results, we proposed the coexistence of two opposite attentional effects with eye gaze: a standard spatial interference component being common to both arrows and gaze, and a larger social-specific dimension leading to the overall reversion of the effect for gaze. Both in Experiment 1 and 2, gaze or arrow targets were presented after or concurrently with an irrelevant background (asynchronous vs. synchronous conditions, respectively). Consistent with our preregistered hypotheses, the standard effect with arrows was present in the asynchronous condition (automatic figure–ground segregation) but reduced in the synchronous one (difficult figure–ground segregation). Correspondingly with the effect on arrows interference, eye gaze triggered a significant reversed effect in the synchronous condition that decreased in the asynchronous one. These results underline the importance of the figure–ground segregation processes as modulators of the spatial conflict triggered by peripheral targets, and support our two-effect model that gaze shares with non-social stimuli a domain-general orienting mechanism, but also triggers distinctive processes
Effective hard-sphere model of diffusion in aqueous polymer solutions
No full textAn effective hard-sphere model of the diffusion and cross-diffusion of salt in unentangled polymer solutions is developed. Given the viscosity, sedimentation coefficient and osmotic pressure of the polymer, the model predicts the diffusion and cross-diffusion coefficients as functions of the polymer concentration and molecular weight. The results are compared with experimental data on NaCl diffusion in aqueous polyethylene glycol solutions, showing good agreement at polymer molecular weights up to 400 g/L. At higher molecular weights the model becomes less accurate, likely because of the effects of entanglement. The tracer Fickian diffusivity can be written in the form of a Stokes-Einstein equation containing the solution viscosity. For NaCl diffusion in polyethylene glycol solutions, the Stokes-Einstein equation breaks down as the polymer size increases. Using Batchelor’s viscous correction factor to determine an effective viscosity experienced by the salt ions within the polymer matrix leads to much closer agreement with experiment
From Teachers’ Personal Achievement Goals to Students’ Perceptions of Classroom Goal Structures: Via Student-oriented Goals and Specific Instructional Practices
No full textWhile research has documented associations between teachers’ achievement goals and students’ perceptions of classroom goals, little is known about the mechanisms behind these effects. To enlighten the mode of operation of teacher goals on students’ perceptions of instructional practices and classroom goal structures, a study with 84 secondary school teachers and their 1,447 students (ranging from 7th to 9th grade) in the subject of mathematics was conducted. Classroom goal structures and a wide range of specific mastery and performance-oriented instructional practices derived from Ames’ (1992) TARGET model were assessed via student reports. Teachers reported two types of goals, namely personal achievement goals and student-oriented goals. Two-level path modeling indicated that both types of teacher goals were of relevance. Student reports of teachers’ specific mastery-oriented instructional practices were predicted by teachers’ student-oriented goals and, indirectly, by their personal mastery goals (positively) and performance approach goals (negatively), while performance-oriented instructional practices were negatively predicted by teachers’ personal mastery goals. Perceived classroom goal structures were closely related to these specific instructional practices and also indirectly predicted by teachers’ personal and student-oriented goals
Комп’ютерне моделювання асинхронного генератора для вітроелектростанції
Get PDFA pressing problem in the modern economy is still the problem of generating a sufficient amount of electricity. The situation is aggravated by environmental problems when using so-called carbon energy, as well as when using hydro and nuclear energy. The development of alternative sources of electricity is now impossible to imagine without the use of wind power plants. Wind energy is practically free energy, but its use involves the use of electric generators. Currently these are mainly synchronous generators, but induction (asynchronous) generators are also used. Despite the relative cheapness and reliability, however, induction generators occupy a very modest place in percentage terms among wind generators. One of the problems with using induction wind generators is that they require very significant reactive power during operation, which either comes from the network or is compensated by a capacitor bank. The latter is typical for autonomous induction generators. Computer modeling of induction wind generators is complicated by significant nonlinearity, which is caused by the magnetization curve or, what is the same, the no-load characteristics of the generator. As a rule, in computer modeling or simulation the inductive reactance of the magnetization branch is assumed to be constant, which is not entirely correct, since it is reliably known that it depends on the rotor rotation speed. A number of models of an induction generator are known, but so far there is no one most reliable mathematical model that allows computer studies of an induction generator with a squirrel-cage rotor, taking into account all its features. The MATLAB 2023b software package contains a mathematical model of an induction wind generator, which is of scientific and practical interest. The article examines the capabilities of this model, its advantages and disadvantages. The dependences of the influence of machine parameters on the generated active power and consumed reactive power were obtained, the influence of the inductive resistance of the magnetization branch and the influence of the nature of the load on the generated energy by the generator were assessedАктуальною проблемою сучасної економіки все ще залишається проблема вироблення достатньої кількості електроенергії. Ситуація погіршується екологічними проблемами при використанні так званої вуглецевої енергетики, а також при використанні гідро- та атомної енергетики. Розвиток альтернативних джерел електроенергії неможливо зараз уявити без використання вітроелектростанцій. Енергія вітру практично дармова енергія, проте її використання передбачає застосування електрогенераторів. В даний час це переважно синхронні генератори, але також використовуються і асинхронні генератори. Незважаючи на відносну дешевизну та надійність, проте, асинхронні генератори займають дуже скромне місце у відсотковому відношенні серед вітрогенераторів. Однією з проблем використання асинхронних вітрогенераторів є те, що їм потрібна при роботі дуже значна реактивна потужність, яка надходить з мережі або компенсується батареєю конденсаторів. Останнє й у автономних асинхронних генераторів. Комп'ютерне моделювання асинхронних вітрогенераторів ускладнюється суттєвою нелінійністю, яка обумовлена кривою намагнічування або, що, те саме, характеристикою холостого ходу генератора. Як правило, при комп'ютерному моделюванні індуктивний опір вітки намагнічування приймається постійним, що є не зовсім коректним, оскільки достовірно відомо, що воно залежить від частоти обертання ротора. Відомий ряд моделей асинхронного генератора, але поки що не існує однієї найбільш достовірної математичної моделі, що дозволяє проводити комп'ютерні дослідження асинхронного генератора з короткозамкненим ротором з урахуванням усіх його особливостей. У програмному пакеті MATLAB 2023б є математична модель асинхронного вітрогенератора, яка представляє науковий та практичний інтерес. У статті досліджено можливості даної моделі, її переваги та недоліки. Отримано залежності впливу параметрів машини на активну і реактивну потужність, що виробляється та споживається відповідно, оцінено вплив індуктивного опору гілки намагнічування і вплив характеру навантаження на вироблювану енергію генераторо
Training enhances fidelity of color representations in visual long-term memory
No full textVisual perception can be affected by training mental representations. However, it remains unclear if training procedures can also affect the quality of mental representations. To investigate if training enhances the fidelity of mental representations retrieved from visual long-term memory (VLTM), we used a task including object-color associations with a continuous response-space. We tested 15 participants in a training group, and 15 participants in a control group. Training consisted of six training runs executed on three consecutive days. Before and after training, we assessed accessibility and fidelity of mental representations in VLTM, and of single objects in visual short-term memory (VSTM). Not only accessibility to mental representation but also their fidelity increased across training and transferred to novel object-color associations in VLTM and VSTM after training. At the end of the training, fidelity of VLTM representations were virtually identical to fidelity of VSTM representations. We conclude, that training object-color associations does not only improve the accessibility of VLTM representations, but also their fidelity based on perceptual plasticity of the visual system
Boosting the impact of charitable giving
No full textThe most effective charities are hundreds of times more impactful than typical charities. Yet most donors favor charities with personal/emotional appeal over effectiveness. We gave donors the option to split their donations between their personal favorite charity and an expert-recommended highly effective charity. This bundling technique increased donors’ impact without undermining their altruistic motivation, boosting effective donations by 76%. An additional boost of 55% was achieved by offering matching donations with increasing rates for allocating more to the highly effective charity. We show further that matching funds can be provided by donors focused on effectiveness through a self-sustaining process of micro-matching. We applied these techniques in a new online donation platform (GivingMultiplier.org) which fundraised over 1.5 million USD in its first 14 months. While prior applied research on altruism has focused on the quantity of giving, the present results demonstrate the value of focusing on the effectiveness of altruistic behavior
Change in Anti-COVID-19 Behavior and Prejudice against Minorities during the COVID-19 Pandemic: Longitudinal Evidence from Five European Countries
No full textIn the COVID-19 pandemic, it is vital to identify factors increasing behaviors that limit the transmission of COVID-19 (i.e., anti-COVID-19 behavior) and factors protecting against the negative consequences of the pandemic on societies (i.e., prejudice). A simultaneous investigation of a change in anti-COVID behavior and prejudice during the pandemic is essential because some factors (e.g., fear of COVID-19) could increase both outcomes, whilst other factors (e.g., norms in anti-COVID behavior or intergroup contact in prejudice) could bring desirable changes in one outcome without negatively affecting the other. In a three-wave longitudinal study (NT1 = 4275) in five European countries from April to October 2020, we employed a latent change score model to distinguish between intra- and inter-individual changes in anti-COVID-19 behavior and prejudice. On the intra-individual level, anti-COVID-19 behavior was increased by anti-COVID-19 norms; and prejudice against migrants from the Middle East was influenced by positive and negative direct and mass-media intergroup contact