Miracle-dz/UniFAR-FTUs huggingface dataset:
Estudio del refrigerante R 134 a en estado bifásico circulando en un tubo horizontal Trabajo Fin de Grado

High heat transfer rates at reasonably low temperature differences can be obtained by utilizing a boiling fluid. However, the behaviour of the heat transfer coefficient becomes much more intricate, revealing the modelling of this behaviour quite complex. Nevertheless, a good model of this twophase flow allows for an optimal design and, thus, a safer system with a higher efficiency regarding heat transfer. An extensive research has been conducted in the past decades on this topic, however, many aspects remain unexplored. The literature survey presented in this work condenses previous results in a chronological order, gradually showing new discoveries and corrections on previous models. Yielding, in the end, a wide review of the state of the art on boiling R134a inside an horizontal, small diameter tube. The purpose of this study is to perform an experimental investigation on an unexplored region, obtaining new results that may contribute for the elaboration of a more accurate model. For this end, a deep study was performed on the different aspects exhibited on the experimental results together with a comparison with the literature survey, allowing for the extrapolation of new conclusions on the topic. Experiments were conducted inside a 5mm internal diameter tube with a pressure of 5.5 bar, mass fluxes ranging from 200kg/m2s to 400kg/m2s and heat fluxes ranging from 15.8kW/m2 to 47.8kW/m2. Under these conditions, due to the high heat flux and pressure selected, the nucleate boiling contribution on the heat transfer was found significantly stronger than the convective contribution. As a result, the heat transfer coefficient presented a strong dependence on the heat flux, while the effect of mass flux was only important for higher vapour qualities, were the convective heat transfer mechanism gains strength. Deep focus was also made on the dryout region, revealing interesting behaviours regarding both the vapour quality at which dryout occurred and the HTC achieved at dryout inception. Moreover, a sharp increase of the heat transfer coefficient was found before dryout inception, this feature had been reported only once prior to this project and the experimental results presented in this work have revealed resourceful for the investigation of this new characteristic.
Different Types of Liberalization and Jobs in South Korean Firms

This study examines the effects of several factors indicating economic openness- imported intermediate goods, total imports, IFDI (inward foreign direct investment), and foreign ownership-on regular, irregular jobs and the ratio of irregular employment to regular employment. Findings revealed that imported intermediate inputs and IFDI affected neither regular nor irregular job figures. However, an increase in total imports led to a decrease in the number of irregular jobs without affecting regular full time jobs, leading to a decrease in the ratio of irregular jobs to regular jobs. On the other hand, changes in foreign ownership structure had a contrary effect, that is, a decrease in the number of regular jobs and an increase in irregular ones, and, thus, an increase in the ratio of irregular jobs to regular jobs. Overall results showed that a rise in imports results in depressed overall employment, irregular employment in particular, while more IFDI results in more irregular jobs replacing regular ones, effectively exacerbating job insecurity. The implication of this analysis is that greater economic openness may have a negative impact on the South Korean labor market overall.
Exploring practitioners’ perceptions of risk when delivering Forest School for 3- to 5-year-old children

ABSTRACT Forest School has grown in UK popularity, providing young children with opportunities for fun and risky play, and time in nature. Focus groups and semi-structured interviews were used to explore student practitioner and nursery practitioner perspectives about risk when delivering Forest School with pre-school children; participant views on risk were sought before and after engagement in five Forest School sessions. The study found that risk is a flexible term for early years practitioners. Whilst participants saw the benefits, there was also anxiety about upholding regulations or fear of blame. Additionally, practitioners’ perceptions of risk changed after the Forest School sessions, suggesting the more experience practitioners have, the less anxious they are about the risks of delivering Forest School sessions with young children.
Investigating the effect of information systems factors on trust in e-government initiative adoption in palestinian public sector

The study conducted a primary investigation into the relationship between information system and trust in e-government followed by a secondary one into the relationship between trust in e-government and intention to use. It followed a quantitative approach of data collection through the use of questionnaire survey. The findings revealed that information quality, system quality, service quality, perceived usefulness, perceived ease of use, and security- privacy contributed positively to trust in e-government while the latter impacted intention to use. Moreover, the study's findings supported the rationale behind the IS theories (TAM and IS Success Model) and security-privacy were proven to illustrate trust in e-government adoption initiative. The findings theoretical and practical implications and limitation and suggestions for future research were discussed towards the end of the study.
A Preliminary Investigation of the factorial validity of the Four- Dimensional Symptom Questionnaire (4DSQ) in the Zimbabwean working population

The purpose of this study was to investigate the factorial validity of the 4DSQ in a Zimbabwean working population. The 4DSQ is a recently developed measure of distress, depression, anxiety and somatisation developed by Terluin (1996). An online survey was administered through survey monkey to employees on the database of a local consulting firm. A convenient sample (N= 819) provided the data set for this analysis. The Cronbach’s α for the 4DSQ ranged from . 89 to . 96 based on the whole sample. The sample was randomly split into two samples; test sample (N= 410) and holdout sample (409). The data on the test sample was subjected to exploratory factor analysis yielding 4 factors. When subjected to confirmatory factor analysis 3 factors fitted the data better than the 4 factor model. The three factors in the new scale are depression, anxiety and somatisation excluding the distress factor. The 3 factor scale was then validated on holdout sample and it was replicated. The Cronbach’s α for the 3 factor scale ranged from . 78 to . 96. Results are discussed in relation to the Zimbabwean context.
Doping concentration variation in the barrier layers of a 462 nm In0.02Ga0.98N QW laser for structure performance improvement

Lasers with quantum wells, based on the InGaN material system, have been researched for more than a decade, taking advantage from their wide bandgap energy, high emission efficiency and possibility of working in various spectra (red, green, blue, ultraviolet). We investigated if, for a structure of a 462 nm (blue) In0.02Ga0. 98N QW laser, the variation of doping concentration in the barrier layers of the structure may lead to obtaining a lower threshold current, a higher slope efficiency and external differential quantum efficiency.
Memory allocation in distributed storage networks

We consider the problem of distributing a file in a network of storage nodes whose storage budget is limited but at least equals the size file. We first generate T encoded symbols (from the file) which are then distributed among the nodes. We investigate the optimal allocation of T encoded packets to the storage nodes such that the probability of reconstructing the file by using any r out of n nodes is maximized. Since the optimal allocation of encoded packets is difficult to find in general, we find another objective function which well approximates the original problem and yet is easier to optimize. We find the optimal symmetric allocation for all coding redundancy constraints using the equivalent approximate problem. We also investigate the optimal allocation in random graphs. Finally, we provide simulations to verify the theoretical results.
Modeling the role of the close-range effect and environmental variables in the occurrence and spread of Phragmites australis in four sites on the Finnish coast of the Gulf of Finland and the Archipelago Sea

Phragmites australis, a native helophyte in coastal areas of the Baltic Sea, has significantly spread on the Finnish coast in the last decades raising ecological questions and social interest and concern due to the important role it plays in the ecosystem dynamics of shallow coastal areas. Despite its important implications on the planning and management of the area, predictive modeling of Phragmites distribution is not well studied. We examined the prevalence and progression of Phragmites in four sites along the Southern Finnish coast in multiple time frames in relation to a number of predictors. We also analyzed patterns of neighborhood effect on the expansion and disappearance of Phragmites in a cellular data model. We developed boosted regression trees models to predict Phragmites occurrences and produce maps of habitat suitability. Various Phragmites spread figures were observed in different areas and time periods, with a minimum annual expansion rate of 1% and a maximum of 8%. The water depth, shore openness, and proximity to river mouths were found influential in Phragmites distribution. The neighborhood configuration partially explained the dynamics of Phragmites colonies. The boosted regression trees method was successfully used to interpolate and extrapolate Phragmites distributions in the study sites highlighting its potential for assessing habitat suitability for Phragmites along the Finnish coast. Our findings are useful for a number of applications. With variables easily available, delineation of areas susceptible for Phragmites colonization allows early management plans to be made. Given the influence of reed beds on the littoral species and ecosystem, these results can be useful for the ecological studies of coastal areas. We provide estimates of habitat suitability and quantification of Phragmites expansion in a form suitable for dynamic modeling, which would be useful for predicting future Phragmites distribution under different scenarios of land cover change and Phragmites spatial configuration.
O Impacto de Choques Fiscais na Economia Brasileira: Uma Abordagem DSGE

O objetivo deste trabalho e estimar a importância relativa de consumidores ricardianos e nao-ricardianos na economia brasileira e analisar o impacto de choques nos gastos do governo no consumo privado utilizando um modelo dinâmico estocastico de equiĺibrio geral (DSGE). Os parâmetros do modelo sao estimados utilizando-se metodos de inferencia Bayesiana. Conclui-se que a importância dos consumidores nao-ricardianos no Brasil e baixa, proxima de 10% e que sua presenca afeta os demais parâmetros do modelo. Em resposta aos choques nos gastos do governo, verifica-se que o modelo falha em conter a queda no consumo privado devido a alta persistencia dos choques e que ha um apertamento da poĺitica monetaria visando conter o aumento da inflacao.
The prevention of muscle pains associated with the use of suxamethonium.

The incidence and severity of muscle pain was assessed in 150 males who underwent bronchoscopy using thiopentone and suxamethonium iodide or chloride for anaesthesia. In 50 patients tubocurarine 3–5 mg, diplacin 10–15 mg or kvalidil 10–15 mg was injected intravenously after the induction dose of thiopentone. In a further group of 50 patients neostigmine 0.5–0.75 mg was injected intramuscularly 20–30 minutes after bronchoscopy. The remaining 50 patients were not given either of these treatments and formed a control group. Six patients developed pain when non-depolarizing relaxants had been used compared with 29 in the neostigmine group and 40 in the control group.
Fast In-Memory SQL Analytics on Graphs

We study a class of graph analytics SQL queries, which we call relationship queries. Relationship queries are a wide superset of fixed-length graph reachability queries and of tree pattern queries. Intuitively, it discovers target entities that are reachable from source entities specified by the query. It usually also finds aggregated scores, which correspond to the target entities and are calculated by applying aggregation functions on measure attributes, which are found on the target entities, the source entities and the paths from the sources to the targets. We present real-world OLAP scenarios, where efficient relationship queries are needed. However, row stores, column stores and graph databases are unacceptably slow in such OLAP scenarios. We briefly comment on the straightforward extension of relationship queries that allows accessing arbitrary schemas. The GQ-Fast in-memory analytics engine utilizes a bottom-up fully pipelined query execution model running on a novel data organization that combines salient features of column-based organization, indexing and compression. Furthermore, GQ-Fast compiles its query plans into executable C++ source codes. Besides achieving runtime efficiency, GQ-Fast also reduces main memory requirements because, unlike column databases, GQ-Fast selectively allows more dense forms of compression including heavy-weighted compressions, which do not support random access. We used GQ-Fast to accelerate queries for two OLAP dashboards in the biomedical field. It outperforms Postgres by 2-4 orders of magnitude and outperforms MonetDB and Neo4j by 1-3 orders of magnitude when all of them are running on RAM. In addition, it generally saves space due to the appropriate use of compression methods.
The Tracking Wars: State Reform Meets School Policy

In the 1980s, a nationwide reform movement sprang up in opposition to "tracking," the controversial practice of schools grouping students by ability and organizing curriculum by level of difficulty. Officials in two states, Massachusetts and California, adopted policies urging middle schools to reduce or abandon tracking. In this book, Tom Loveless describes how schools reacted to these recommendations and discusses why some schools went along with detracking while others bitterly resisted the reform. Loveless explains that the state policies were adopted without strict mandates, financial incentives, legal threats, or new bureaucratic structures. They were also adopted without convincing evidence that detracking brings lasting benefits to students. But advocates framed tracking reform as a policy supporting greater educational equity. In response, urban schools, low-achieving schools, and schools serving disadvantaged children have reacted sympathetically to the reform. Suburban schools, high-achieving schools, and schools serving wealthier families have been less willing to detrack. Drawing on extensive survey and case study data, Loveless concludes that this reform's fate is in the hands of local decisionmakers. Schools formulate tracking policy based on their own institutional, organizational, political, and technical considerations. All school reform entails risks. One troubling implication of this study is that the risks of detracking are being assumed by schools with some of society's most vulnerable youngsters.
Multiple Dose-Dependent Effects of Lis1 on Cerebral Cortical Development

Humans with heterozygous inactivating mutations of theLis1 gene display type I lissencephaly, a severe form of cortical dysplasia hypothesized to result from abnormal neuronal migration. Previously we reported the construction of an allelic series of the Lis1 gene in mice to analyze the effects of graded reduction of LIS1 protein on the pathogenesis of this disorder and demonstrated a cell autonomous defect in neuronal migration (Hirotsune et al., 1998). Here we report the systematic examination of the consequences of dosage reduction of LIS1 on neocortical development using wild-type, null heterozygous (45% LIS1 protein), and compound null/hypomorphic (35% LIS1 protein) mice. The development of the preplate, Cajal-Retzius cells, and the radial glial scaffold appeared unaffected by LIS1 levels. However, a dose-dependent morphologic change in disorganization of the subplate was noted. LIS1 dose-dependent defects in neuronal migration were found in vivo andin vitro. The position and number of mitotic cells in the ventricular zone were more abnormal as LIS1 levels decreased, suggesting defects in interkinetic nuclear migration and neuroblast proliferation. LIS1 dose-dependent progressive thinning of the cortex and ventricular zone occurred by programmed cell death. Thus, in addition to its requirement for cell autonomous neuronal migration, LIS1 influences the generation and survival of cortical ventricular zone neuroblasts. These studies reveal the importance of LIS1 levels in orderly cerebral cortical morphogenesis and suggest new insights into the pathogenesis of type I lissencephaly.
Operating systems support for busy Internet servers

The Internet has experienced exponential growth in the use of the World-Wide Web, and rapid growth in the use of other Internet services such as USENET news and electronic mail. These applications qualitatively differ from other network applications in the stresses they impose on busy server systems. Unlike traditional distributed systems, Internet servers must cope with huge user communities, short interactions, and long network latencies. Such servers require different kinds of operating system features to manage their resources effectively.
Zero-day Malware Detection based on Supervised Learning Algorithms of API call Signatures

Zero-day or unknown malware are created using code obfuscation techniques that can modify the parent code to produce offspring copies which have the same functionality but with different signatures. Current techniques reported in literature lack the capability of detecting zero-day malware with the required accuracy and efficiency. In this paper, we have proposed and evaluated a novel method of employing several data mining techniques to detect and classify zero-day malware with high levels of accuracy and efficiency based on the frequency of Windows API calls. This paper describes the methodology employed for the collection of large data sets to train the classifiers, and analyses the performance results of the various data mining algorithms adopted for the study using a fully automated tool developed in this research to conduct the various experimental investigations and evaluation. Through the performance results of these algorithms from our experimental analysis, we are able to evaluate and discuss the advantages of one data mining algorithm over the other for accurately detecting zero-day malware successfully. The data mining framework employed in this research learns through analysing the behavior of existing malicious and benign codes in large datasets. We have employed robust classifiers, namely Naive Bayes (NB) Algorithm, k--Nearest Neighbor (kNN) Algorithm, Sequential Minimal Optimization (SMO) Algorithm with 4 differents kernels (SMO - Normalized PolyKernel, SMO -- PolyKernel, SMO -- Puk, and SMO- Radial Basis Function (RBF)), Backpropagation Neural Networks Algorithm, and J48 decision tree and have evaluated their performance. Overall, the automated data mining system implemented for this study has achieved high true positive (TP) rate of more than 98.5%, and low false positive (FP) rate of less than 0.025, which has not been achieved in literature so far. This is much higher than the required commercial acceptance level indicating that our novel technique is a major leap forward in detecting zero-day malware. This paper also offers future directions for researchers in exploring different aspects of obfuscations that are affecting the IT world today.
Consistency-preserving edit scripts in model versioning

In model-based software development, models are iteratively evolved. To optimally support model evolution, developers need adequate tools for model versioning tasks, including comparison, patching, and merging of models. A significant disadvantage of tools currently available is that they display, and operate with, low-level model changes which refer to internal model representations and which can lead to intermediate inconsistent states. Higher-level consistency-preserving edit operations including refactorings are better suited to explain changes or to resolve conflicts. This paper presents an automatic procedure which transforms a low-level difference into an executable edit script which uses consistency-preserving edit operations only. Edit scripts support consistent model patching and merging on a higher abstraction level. Our approach to edit script generation has been evaluated in a larger real-world case study.
Sex matters: secular and geographical trends in sex differences in coronary heart disease mortality

Abstract Objective: To examine secular trends and geographical variations in sex differences in mortality from coronary heart disease and investigate how these relate to distributions in risk factors. Design: National and international data were used to examine secular trends and geographical variations in sex differences in mortality from coronary heart disease and risk factors. Setting: England and Wales, 1921-98; Australia, France, Japan, Sweden, and the United States, 1947-97; 50 countries, 1992-6. Data sources: Office for National Statistics, World Health Organization, and Food and Agriculture Organization of the United Nations. Results: The 20th century epidemic of coronary heart disease affected only men in most industrialised countries and had a very rapid onset in England and Wales, which has been examined in detail. If this male only epidemic had not occurred there would have been 1.2 million fewer deaths from coronary heart disease in men in England and Wales over the past 50 years. Secular trends in mean per capita fat consumption show a similar pattern to secular trends in coronary heart disease mortality in men. Fat consumption is positively correlated with coronary heart disease mortality in men (r s =0.79; 95% confidence interval 0.70 to 0.86) and inversely associated with coronary heart disease mortality in women (—0.30; —0.49 to —0.08) over this time. Although sex ratios for mortality from coronary heart disease show a clear period effect, those for lung cancer show a cohort effect. Sex ratios for stroke mortality were constant and close to unity for the entire period. Geographical variations in the sex ratio for coronary heart disease were associated with mean per capita fat consumption (0.64; 0.44 to 0.78) but were not associated with the sex ratio for smoking. Conclusion: Sex differences are largely the result of environmental factors and hence not inevitable. Understanding the factors that determine sex differences has important implications for public health, particularly for countries and parts of countries where the death rates for coronary heart disease are currently increasing. What is already known on this topic Mortality for coronary heart disease is greater in men than women in most industrialised countries The most widely accepted explanation for this difference is that women are protected by oestrogen What this study adds The sex difference in mortality from coronary heart disease varies over time and between countries in a way that cannot be explained by endogenous oestrogen These trends indicate that sex differences in mortality from coronary heart disease are driven primarily by environmental factors Sex differences in coronary heart disease are not inevitable Understanding more about the factors that cause the sex differences in mortality from coronary heart disease has important public health implications