Assessment of CTF boiling transition and critical heat flux modeling capabilities using the OECD/NRC BFBT and PSBT benchmark databases

The need to refine models for best-estimate calculations, based on good-quality experimental data, has been expressed in many recent meetings in the field of nuclear applications. The modeling needs arising in this respect should not be limited to the currently available macroscopic methods but should be extended to next-generation analysis techniques that focus on more microscopic processes. One of the most valuable databases identified for the thermalhydraulics modeling was developed by the Nuclear Power Engineering Corporation (NUPEC), Japan. From 1987 to 1995, NUPEC performed steady-state and transient critical power and departure from nucleate boiling (DNB) test series based on the equivalent full-size mock-ups. Considering the reliability not only of the measured data, but also other relevant parameters such as the system pressure, inlet sub-cooling and rod surface temperature, these test series supplied the first substantial database for the development of truly mechanistic and consistent models for boiling transition and critical heat flux. Over the last few years the Pennsylvania State University (PSU) under the sponsorship of the U.S. Nuclear Regulatory Commission (NRC) has prepared, organized, conducted and summarized the OECD/NRC Full-size Fine-mesh Bundle Tests (BFBT) Benchmark. The international benchmark activities have been conducted in cooperation with the Nuclear Energy Agency/Organization for Economic Co-operation and Development (NEA/OECD) and Japan Nuclear Energy Safety (JNES) organization, Japan. Consequently, the JNES has made available the Boiling Water Reactor (BWR) NUPEC database for the purposes of the benchmark. Based on the success of the OECD/NRC BFBT benchmark the JNES has decided to release also the data based on the NUPEC Pressurized Water Reactor (PWR) subchannel and bundle tests for another follow-up international benchmark entitled OECD/NRC PWR Subchannel and Bundle Tests (PSBT) benchmark. This paper presents an application of the joint Penn State University/Technical University of Madrid (UPM) version of the well-known subchannel code COBRA-TF, namely CTF, to the critical power and departure from nucleate boiling (DNB) exercises of the OECD/NRC BFBT and PSBT benchmark

Договори у житловому праві: особливості та система

The article aims to identify the characteristics and system of contracts within housing law. The need for investigating this topic arises from both scientific and practical necessities. In practice, there have been instances of abuse of housing rights. Simultaneously, contractual regulation serves as a mechanism to address these adverse manifestations of subjective rights. In the realm of academic research, there have been sporadic examinations of the legal nature and classification of contracts in housing law, highlighting the relevance of the article’s theme. The objective of this article is to elucidate the specific features and system of contracts in housing law. Contracts in housing law exhibit the following characteristics: they combine dispositive and imperative principles and norms; their normative-legal regulation is based on the provisions of civil and housing legislation; they are aimed at satisfying housing needs. It is emphasized that the parties to a housing-law contract, in cases established by law, lack: freedom of choice, independence, autonomy. These dispositive principles are constrained by the requirements of safety, sufficiency/adequacy of housing. The basis for housing safety is its compliance with technical and sanitary norms. Practically all contracts in housing law are concluded in written form. In Ukraine, standard conditions are established regarding individual housing contracts. The system of contracts in housing law represents a complex internal structure of contracts concerning housing, satisfying housing needs based on their hierarchical division into types, kinds, and varieties, reflecting their differentiation and interrelation. It is concluded that contracts in housing law can be divided depending on the following criteria: stage/order of establishing contract conditions, subject matter, cost, form, by purpose (legal consequence), type of housing need, the existence of requirements for standardization. Depending on the type of housing need, they can be divided into: 1) contracts aimed at satisfying primary housing needs (acquisition of housing rights); 2) contracts aimed at ensuring adequate living conditions in housing (satisfying derivative housing needs, including contracts for the consumption of housing and communal services, repair, housing insurance, etc.).Стаття присвячена визначенню особливостей та системи договорів у житловому праві. Підкреслено, що договори у житловому праві мають наступні особливості: в них поєднані диспозитивні та імперативні засади та норми; їх нормативно-правове регулювання ґрунтується на положеннях цивільного та житлового законодавства; вони спрямовані на задоволення житлової потреби. Імперативність у житлово-правових договорах має прояв у тому, що сторони, у випадках визначених законодавством, не можуть відмовитися від укладання договору, самостійно змінювати певні умови договору, на своє уявлення здійснювати суб’єктивні права щодо вселення та проживання у житлі ін. Водночас диспозитивні засади обмежуються вимогами безпечності, достатності/адекватності житла. У договірних зобов’язаннях суб’єктивні житлові права, обмежені вимогами щодо недопустимого впливу на здоров’я людини, які обумовлені станом житла, умовами проживання людини у житлі. Визначено, що стосовно договорів щодо набуття права на житло, встановлено обмеження щодо мети використання житла – виключно для проживання. Виокремлені наступні групи житлово-правових договорів: 1) основні договори (набуття права на житло); 2) похідні договори (укладаються для безпечної та достатньої/адекватної експлуатації житла/житлового фонду); 3) допоміжні договори (спрямовані щодо створення додаткових механізмів забезпечення та реалізації права на житло). Договори у житловому праві, можуть поділятися залежно від: 1) виду житлової потреби (договори, спрямовані на задоволення первинної житлової потреби (набуття права на житло)); договори, що спрямовані на задоволення достатніх умов проживання у житлі (задоволення похідної житлової потреби, зокрема договори щодо споживання житлово-комунальних послуг); 2) встановлених типових умов договорів (договори, укладені за типовими умовами та договори, укладені за умовами, визначені сторонами); 3) від предмету (договори щодо створення житла, спрямовані на набуття права на житло, договори щодо надання житлово-комунальних послуг, договори щодо надання допоміжних послуг)

Evolution and pleiotropy of TRITHORAX function in \u3ci\u3eArabidopsis\u3c/i\u3e

The SET domain-containing genes of the TRITHORAX family encode epigenetic factors that maintain the expression of targeted genes. Trithorax homologs have been found in both animals and plants. Since these are thought to have evolved multicellularity independently, common mechanisms of epigenetic regulation must be evolutionarily ancient and derived from a common ancestor. In addition, each lineage has evolved unique mechanisms to expand the original repertoire of epigenetic functions. Phylogenetic analysis of SET domain proteins has outlined some intriguing evolutionary trends. In plants, epigenetic gene silencing mechanisms have been aggressively pursued. In contrast, studies of epigenetic mechanisms maintaining active gene expression have been scarce. The goal of this review is to draw attention to this gap. Trithorax function in plants are analyzed here in an evolutionary context tracing phylogenetic relationships between the histone methyltransferase activities in unicellular and multicellular domains of life. The involvement of two members of the Arabidopsis Trithorax family, ARABIDOPSIS HOMOLOG of TRITHORAX1 (ATX1), and ARABIDOPSIS HOMOLOG of TRITHORAX2 (ATX2), in developmental and adaptation processes of the plant is overviewed

Transcriptional ‘memory’ of a stress: transient chromatin and memory (epigenetic) marks at stress-response genes

Drought, salinity, extreme temperature variations, pathogen and herbivory attacks are recurring environmental stresses experienced by plants throughout their life. To survive repeated stresses, plants provide responses that may be different from their response during the first encounter with the stress. A different response to a similar stress represents the concept of ‘stress memory’. A coordinated reaction at the organismal, cellular and gene/genome levels is thought to increase survival chances by improving the plant’s tolerance/ avoidance abilities. Ultimately, stress memory may provide a mechanism for acclimation and adaptation. At the molecular level, the concept of stress memory indicates that the mechanisms responsible for memory-type transcription during repeated stresses are not based on repetitive activation of the same response pathways activated by the first stress. Some recent advances in the search for transcription ‘memory factors’ are discussed with an emphasis on super-induced dehydration stress memory response genes in Arabidopsis

Dental fear, anxiety, and phobia; causes, diagnostic criteria and the medical and social impact

Despite technological advances in modern medical science and practice, many people still associate dental treatment with unpleasant emotional sensations and pain. According to the current literature, dental fear and anxiety are psychological barriers that negatively affect frequency of patient attendance which results in avoidant behavior and poorer oral health-related quality of life. This paper was therefore aimed at discussing basic theoretical aspects concerning diagnostic criteria, causes, and impacts of dental fear, anxiety, and phobia. Clarifying their differential diagnostic characteristics, clinical features and specific causes may play an important role in proper diagnosing, positive influencing, and management of this group of patients, thus providing the opportunity for increasing quality of dental healthcare services as well as improving patient’s dental health and self-perceived quality of life

Prevalence of depression, anxiety and stress after the COVID-19 pandemic period among students at the Medical University of Sofia; Significance of demographic, educational, and pandemic-related variables

This cross-sectional study aimed to determine the prevalence of depression, anxiety, and stress among undergraduate dental students at Sofia Medical University and to investigate its associations with some demographic, educational and pandemic-related variables. A self-reported questionnaire that included the validated DASS-21 scale was administered to a group of 2nd, 3rd, 4th, and 5th year students (n=70, response rate 95.7%). Results indicated abnormal levels of depression, anxiety, and stress in 34.3%, 65.7% and 59.7% of the participants, respectively. A much larger proportion of females suffered from abnormal levels of anxiety (56.6%) as compared with males (9%), p=.003. Single students exhibited significantly higher level of depression (25.4%) than those having a partner (9%), p=.037. Third-year dental students demonstrated higher level of depression (19.4%) compared to 5th year students (1.5%), p=.007 as well as higher stress scores (25.4%) than 2nd year students (17.9%), p=.035. Academic performance (assessed by GPA in this study), dentistry as the first students’ choice when applying for MUS, financial responsibilities, and pandemic-related academic responses were not found significant factors for depression, anxiety, and stress (p\u3e.05). These outcomes highlight the need to provide psychological support programs with special attention on susceptible groups. Dental students should implement preventive measures and adopt coping strategies to manage stress and reduce levels of anxiety and depression

Performance analysis of a caching algorithm for a catch-up television service

The catch-up TV (CUTV) service allows users to watch video content that was previously broadcast live on TV channels and later placed on an on-line video store. Upon a request from a user to watch a recently missed episode of his/her favourite TV series, the content is streamed from the video server to the customer's receiver device. This requires that an individual flow is set up for the duration of the video, and since it is hard to impossible to employ multicast streaming for this purpose (as users seldomly issue a request for the same episode at the same time), these flows are unicast. In this paper, we demonstrate that with the growing popularity of the CUTV service, the number of simultaneously running unicast flows on the aggregation parts of the network threaten to lead to an unwieldy increase in required bandwidth. Anticipating this problem and trying to alleviate it, the network operators deploy caches in strategic places in the network. We investigate the performance of such a caching strategy and the impact of its size and the cache update logic. We first analyse and model the evolution of video popularity over time based on traces we collected during 10 months. Through simulations we compare the performance of the traditional least-recently used and least-frequently used caching algorithms to our own algorithm. We also compare their performance with a "perfect" caching algorithm, which knows and hence does not have to estimate the video request rates. In the experimental data, we see that the video parameters from the popularity evolution law can be clustered. Therefore, we investigate theoretical models that can capture these clusters and we study the impact of clustering on the caching performance. Finally, some considerations on the optimal cache placement are presented

Epigenetic Regulatory Mechanisms in Plants

Genomes are defined by their primary sequence, which provides the genetic blueprint of a species. Eukaryotic DNA functions within the context of chromatin, which provides additional layers of gene regulation referred to as “epigenetic.” The commonly found definition of epigenetics is that of a “study of heritable changes in genome function that occur without a change in DNA sequence.” However, evidence that neuronal gene-expression states are also regulated by epigenetic mechanisms, despite evidence that neuronal cells do not divide, has opened space for a broader unifying definition that keeps “the sense of prevailing usage but avoids constraints imposed by stringently required heritability.” Epigenetic mechanisms regulate developmental programs, stress responses and adaptation, senescence, disease, and various patterns of non-Mendelian inheritance. The totipotency of plant cells, in addition to the ability of plants to withstand biotic, abiotic, and genome stresses, such as changes in chromosome number and massive presence of transposable elements, reflects the plasticity of plant genomes and makes them an excellent system to study epigenetic phenomena. Genome plasticity is determined by the EPIGENOME. DNA methylation and histone modification profiles define epigenomes of animals and plants. The main molecular mechanisms operating in epigenetic phenomena are DNA methylation, histone modifications, and RNA-based mechanisms, often referred to as “the three pillars of epigenetics.” Recent advances in genome research technologies, deep sequencing analysis in particular, have led to an explosion of studies and novel results that are reshaping our views. Noncoding RNAs (ncRNAs) are emerging as central players responsible for the establishment, maintenance, and regulation of plant genome epigenetic structure