Major Subject Of Study Research Articles

Survey on cryptocurrency security attacks and detection mechanisms

Cryptocurrencies have become extremely popular as a form of payment in recent years. They are supported by blockchain, a cutting-edge advanced technology that makes extensive use of cryptographic mechanisms and other sophisticated distributed computing techniques. On these grounds, cryptocurrencies have been a target of several attacks. Cyber-attacks, for example, are exogenous events that can robustly affect cryptocurrencies by influencing their stabilization of price and market valuation. This study describes an overview of cybercriminals’ activities on cryptocurrencies. It provides a detailed discussion on the most popular types of attacks on the cryptocurrency ecosystem. Moreover, it provides possible countermeasures to these attacks. Finally, it produces insights into the most impactful attacks on cryptocurrencies and the best methods that have been proposed for detecting cryptocurrency attacks. The main goal of this survey is to obtain a thorough understanding of cryptocurrency attacks, which have been the subject of major studies concerning financial risks on cryptocurrency. A large number of existing publications have reviewed and assessed various forms of attacks to achieve this goal. However, these works have considerably flawed. To the best of our knowledge, the present survey sheds light on future research directions.

Effects of Supplementation of Saviotan Feed (Chestnut Tannin) on Blood Parameters and Yolk Cholesterol Concentration in Japanese Quails (Coturnix japonica)

Tannins are secondary metabolites and active compounds widely present in plants. Tannins have several properties, such as astringent, antiparasitic, anti-diarrheal, anti-bacterial, and antioxidant. Hence, plants containing tannins are a major study subject for a natural alternative to in-feed antibiotics or antioxidants. The functions of tannin extracted from chestnut wood, namely Saviotan Feed (SF) in poultry, especially in quails, have not yet been fully understood. The current study aimed to examine the effect of SF supplementation on some plasma metabolites, including glucose (GLU), triglyceride (TG), total cholesterol (TCHO) concentration, and yolk cholesterol in quails (Coturnix japonica). A total of 100 unsexed quails were divided into 4 groups, with 25 quails in each group. These quails were then placed into 20 experimental pens, with 5 quails per pen. Each treatment was replicated 5 times, and the quails were fed a commercial rations diet supplemented with different SF doses of 0% (control), 0.1%, 0.2%, and 0.3%. Quails were provided with SF supplementation from 14 to 56 days of age. A sample of 40 plasma and eggs were randomly collected and analyzed for GLU, TG, and TCHO. The results indicated no significant effects of SF on plasma GLU and TG concentration, but a significant effect was found regarding TCHO. Moreover, supplementation of SF from 0.1 to 0.3% significantly decreased TCHO concentration in the yolk. In conclusion, it has been determined that supplementation of SF may play a significant role in decreasing TCHO in yolk eggs in quails.

Perspectives and viewpoints of undergraduate students towards library and information science (LIS) as a major subject of study and preferred profession

Perspectives and viewpoints of undergraduate students towards library and information science (LIS) as a major subject of study and preferred profession

Risk Factors Associated with COVID-19 Mortality in the State of Durango, Mexico.

The coronavirus disease 2019 (COVID-19) has caused over six million deaths worldwide since its emergence in Wuhan China, factors associated with COVID-19 mortality, such as comorbidities, age, and observed symptomatology still remain a major subject of study. In the present work, a total of 16,345 SARS-CoV-2 positive cases from Durango Mexico diagnosed from May 2020 to December 2021 were analyzed to establish an association of COVID-19 mortality with clinical and demographic variables in a case-control study. Selected variables include patient age, smoking status, sex, presence of comorbidities such as hypertension, diabetes and obesity, as well as patient symptomatology such as fever, dyspnea, abdominal pain and diarrhea. Results indicate that among analyzed data, the median age was 43 years; 54% were female, with a mortality rate of 5.66%. Multivariate regression analysis indicated that the comorbidities associated with the highest risk factor were advanced age (>60) with an odds ratio of 4.127 (IC 95%, 3.37-5.05), hypertension with 1.961 (IC 95%, 1.57-2.45), diabetes with 1.753 (IC 95%, 1.39-2.20) and obesity with 1.413 (IC 95%, 1.11-1.78) respectively. On the other hand, the symptom associated with the highest risk factor was dyspnea with an odds ratio of 18.369 (IC 95%, 14.42-23.39). Our data suggests an association between hypertension and old age with COVID-19 mortality. Other findings include the prevalence of dyspnea, polypnea and cyanosis as a major predictor for COVID-19 mortality, as well as lower mortality risks among health workers.

DESIGN AND IMPLEMENTATION OF IMPROVED ENSEMBLE CLASSIFICATION ALGORITHM FOR HUMAN ACTIVITY RECOGNITION (HAR)

To recognize the human activity is considered very essential in human-to-human interaction and interpersonal relations due to its nature of providing information regarding the identity of a people, their personality and psychological state. The extraction of this information is very challenging. The main operation occurred before the systematic fields of computer vision as well as ML is the potential for recognizing the activities of different person. The human activity recognition technique is executed in various stages such as to pre-process the data, extract the features and classifying the data. This work proposes a improved ensemble model in the human activity recognition which is the combination of K-mean clustering, PCA and of multiple classifiers which are merged through voting methodology. Python is executed to get evaluated the presented framework and various metrics such as accuracy, precision and recall are considered to analyse the results. The major subject of study of the scientific and research areas of computer vision and ML is the potential of human for identifying the activities of particular person. A sequence of human body movements in which different body parts (head, hands, legs etc.) are engaged in concurrent manner is known as action.

Intensive Data and Knowledge‐based Approach for Sustainable and Circular Industrial Systems

ABSTRACTThe circular economy and its various recirculation loops have become a major study subject over recent years, particularly the transformation of the actual processes into sustainable processes. However, these environmental analyses require a huge quantity of data: foreground data and background data. The collection of these data can be long and tedious. Nevertheless, an increasing number of scientific articles describe the processes, which is a great source of data. This source of information is heterogeneous but big data tools can be used to compile, process and analyze them.Following this perspective, this paper focus on the creation of methodological framework centered on intensive data and knowledge for an economically viable and ecologically responsible design of industrial processes or systems. Composed of five steps, this approach is oriented towards offering decision support for the researcher or R&D engineer during systems requirements and high‐level design steps of V‐model. It is implemented within the domain of pre‐treatment processes for corn stover.

Tocilizumab In Severe To Critical Confirmed COVID-19: A Case Series At Ulin Referral Hospital Of South Kalimantan

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is a new type of coronavirus that causes pneumonia. The clinical severity of COVID-19 is related to the presence of a “cytokine storm” that causes overproduction of inflammatory mediators such as interleukin (IL)-6. Tocilizumab (TCZ) as an IL-6 inhibitor is subject of major studies as a potential therapeutic agent. This study reported 20 cases of COVID-19 patients being treated with the IL-6 inhibitor TCZ beside standard therapy. Patients were followed up on clinical, laboratory and chest x-rays before and after the administration of therapy which were report descriptively. The oxygen saturation of patients who survived shows rapid improvements. The laboratory results showed that CRP decreased after administration TCZ immediately. Meanwhile, other markers improve slowly, such as leucocytes, Neutrophyl Lymphocyte Ratio (NLR), Absolute Lymphocyte Count (ALC) and Lactate Dehydrogenase (LDH) but ferritin was tended to fluctuate. In chest X-ray’s, infiltrate bilateral on admission began to diminished until almost disappeared on the 14th day after TCZ. From 20 patients, 80% of patients survived with improvement in clinical, laboratory and chest X-rays, while the rest death with a good response on first therapy but fluctuated and worsened before death. Tocilizumab can be considered to provide clinical improvements in severe and critical COVID-19 patients.

Impasses e perspectivas no contexto da escola de tempo integral: uma análise sob o olhar discente

Considerada como um meio para a obtenção de uma educação de qualidade, a educação em tempo integral vem sendo alvo de grandes estudos e discussões, nos últimos anos em nosso país, devido a busca pelo comprometimento com uma formação integral dos estudantes. A discussão em torno dessa modalidade de ensino se dá por sua eficácia quanto ao ensino e a aprendizagem, bem como à formação humana, requisitos fundamentais para a universalização de uma escola pública de qualidade. Nessa conjuntura, este artigo tem como proposta investigar as potencialidades e os desafios da escola de tempo integral na visão dos discentes que estão vinculados às instituições de ensino que ofertam tal modalidade. Por meio de uma abordagem quali-quantitativa, foi aplicado um questionário online a 150 estudantes, matriculados nas três séries do ensino médio em duas escolas de tempo integral, uma no Ceará e outra em Goiás, que apontaram aspectos positivos e negativos quanto a essa modalidade escolar. Por meio da análise dos dados obtidos, foi possível inferir que, mesmo apresentando resultados promissores, esse tipo de modalidade educacional ainda inspira atenção em sua consolidação, visto a necessidade de uma participação conjunta de toda a comunidade escolar para a garantia de uma educação acessível a todos. Sob o olhar discente, a escola de tempo integral é um centro de oportunidades.

Linking the submicroscopic and symbolic level in physical chemistry: how voluntary simulation-based learning activities foster first-year university students’ conceptual understanding

Research in the past decades repeatedly revealed university students’ struggles to properly understand physical chemistry concepts. In contrast to school, tertiary teaching relies heavily on the symbolic level, mainly applying abstract representations such as equations and diagrams. To follow the lessons and generate conceptual understanding, students need to connect those representations with macroscopic and submicroscopic aspects of the scientific concept depicted. For German first-year chemistry students, this increase in abstraction in a major subject of study contributes to excessive demand and demotivation (especially during out-of-class learning) and increases the risk of early dropouts. We designed a simulation-based learning environment (BIRC: Bridging Imagination and Representation in Chemistry) to suit the needs of first-year students and support them when learning physical chemistry at home. Our approach, featuring molecular dynamics simulations, requires students to assess their own mental models on the submicroscopic level and connect them to equations and diagrams on the symbolic level. Prior studies did already highlight the potential of individual BIRC learning units to foster conceptual understanding on specific topics. In this paper, we investigate if and how students of a broader sample use these learning activities as voluntary supplement beside regular coursework. During the term, we used think-aloud protocols, interviews and eight online questionnaires to analyse students’ mental and emotional interaction while working on BIRC, assessing whether students perceived BIRC as a suitable, enjoyable and supportive resource to enhance learning. Via two paper & pencil achievement tests we examined students’ retention concerning submicroscopic mental models and their ability to connect these mental models with symbolic representations 5–10 weeks later. Our findings indicate a cognitively engaging, comparably enjoyable learning process, which strengthens conceptual understanding and – despite the necessary time and effort – induces a broad number of students to voluntarily work on several units at home.

Propagation of Millimeter Waves in Composite Materials

Composite materials have become indispensable in a wide variety of technical fields, where they are viewed as the key technological component. Due to their structural complexity, these materials are prone to errors while in the manufacturing process, thus non-destructive inspecting becomes a crucial step in the processing chain and further maintenance of said material. However, a tomographic characterization of these components is often only possible to a limited extent—a capability which is essential to exploit the full potential of this technology. Measurement systems based on millimeter waves (mmWs) have the potential to achieve exactly that, by providing valuable information on the internal structure of such components. Yet, these non-destructive and non-contact methods have not found wide usage in practical applications. One reason for this is that the effects composite materials have on the propagation behavior of mmW signals have not been a major subject of study in the past. Therefore, a model for predicting the propagation properties of mmW signals in composite materials is presented here. Based on coupled wave analysis, the propagation of arbitrary electromagnetic signals in composite materials can be simulated. These results can be directly incorporated into the design of respective measurement systems. The introduced model is verified through a comparison of simulation and measurement results, obtained via a focused frequency modulated continuous wave (FMCW) radar, operating in the $H$ -band (220–325 GHz), directed at glass fiber reinforced plastic samples.

A screening of select toxic and essential elements and persistent organic pollutants in the fur of Svalbard reindeer.

Reindeers play an important role in the polar ecosystem, being long-lived sole vegetarians feeding on local vegetation. They can be used as a valuable bioindicator, helping us to understand contaminants' impact on the polar terrestrial ecosystem. Still, scarce data exist from research in which polar herbivores (especially those from the European parts of the Arctic) were a major study subject for trace elements and persistent organic pollutant determination. Here, Svalbard reindeer fur has been used to determine metals, non-metals and metalloids using ICP-MS, and several persistent organic pollutants including polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) using gas chromatography coupled to a tandem mass spectrometer (GC-MS/MS). Samples were collected from reindeer populations living in the area near Ny-Ålesund and Longyearbyen. Essential elements like Fe, Mg, Zn, K, Ca, Cu predominated in the trace elements profile. Median values of As, Cd, Co, Li, Ni, Se and V were all below 0.5μg/g dw. Mercury was below detection limit in all samples, while the Pb median varied from 0.35 to 0.74μg/g dw. Except acenaphthylene and fluorene, PAHs were detectable only in samples collected in the vicinity of Longyearbyen. Of 15 studied pesticides, only DDT and its metabolites were above the detection limit, and, of PCBs, only PCB28.

Birth and evolution of the Paleocarnic Chain in the Southern Alps: a review

The present work is aimed at reviewing the state of the art of the studies centered on the pre-collisional and collisional, Variscan evolution of the eastern Southern Alps. The main focus is on the Carnic Alps, a geologically spectacular and extremely complex area, which has been a major subject of study for structural geologists, stratigraphers, and paleontologists for more than a century. After decades of field studies aimed at unveiling the birth and evolution of this belt, the tectonic and geodynamic interpretations proposed for almost a century by two different groups of authors remain substantially different. German-speaking authors, over the decades, have consistently proposed a scenario marked by a mature, Devonian passive margin, which later on evolved into an active Mississippian continental margin; the following collisional phase resulted in an accretionary wedge that, in its evolution, might be compared to those generated by Variscan events outside the Alpine domain. On the contrary, Italian authors have mainly put forward a pre-collisional setting dominated by wrench-fault tectonics, followed by the formation of a large, collisional thrust-and-fold belt, arc-shaped in plan view. We illustrate the results accomplished so far and discuss the interpretations formulated by the two different research schools; our review provides a chance to compare the different interpretations and, at the same time, prompts the need for new and targeted data collection in the area.

Ionic Liquids for the Synthesis of Five-Membered N,N-, N,N,N- and N,N,N,NHeterocycles

Due to special properties of ILs (Ionic Liquids) like their wide liquid range, good solvating ability, negligible vapour pressure, non-inflammability, environment friendly medium, high thermal stability, easy recycling and rate promoters etc. they are used in organic synthesis. The investigation for the replacement of organic solvents in organic synthesis is a growing area of interest due to increasing environmental issues. Therefore, ionic liquids have attracted the attention of chemists and act as a catalyst and reaction medium in organic reaction with high activity. There is no doubt that ionic liquids have become a major subject of study for modern chemistry. In comparison to traditional processes the use of ionic liquids resulted in improved, complimentary or alternative selectivities in organic synthesis. The present manuscript reported the synthesis of multiple nitrogen containing five-membered heterocyclic compounds using ionic liquids. This review covered interesting discoveries in the past few years.

Ionic liquid assisted synthesis of six-membered oxygen heterocycles

Due to special properties of ionic liquids (ILs) like their wide liquid range, good solvating ability, negligible vapour pressure, non-inflammability, environment friendly medium, high thermal stability, easy recycling and rate promoters etc. they are used in organic synthesis. The investigation for replacement of organic solvents in organic synthesis is a growing area of interest due to increasing environmental issues. Therefore, ILs have attracted the attention of chemists and act as catalyst and reaction medium in organic reaction with high activity. There is no doubt that ILs have become a major subject of study for modern chemistry. In comparison to traditional processes the use of ILs resulted in improved, complimentary or alternative selectivities in organic synthesis. The aim of present review is to focus on the applications of ILs for the synthesis of six-membered oxygen heterocycles (pyrans, chromenes, coumarins and dioxanes).

Partners in Mischief: Functional Networks of Heat Shock Proteins of Plasmodium falciparum and Their Influence on Parasite Virulence.

The survival of the human malaria parasite Plasmodium falciparum under the physiologically distinct environments associated with their development in the cold-blooded invertebrate mosquito vectors and the warm-blooded vertebrate human host requires a genome that caters to adaptability. To this end, a robust stress response system coupled to an efficient protein quality control system are essential features of the parasite. Heat shock proteins constitute the main molecular chaperone system of the cell, accounting for approximately two percent of the malaria genome. Some heat shock proteins of parasites constitute a large part (5%) of the ‘exportome’ (parasite proteins that are exported to the infected host erythrocyte) that modify the host cell, promoting its cyto-adherence. In light of their importance in protein folding and refolding, and thus the survival of the parasite, heat shock proteins of P. falciparum have been a major subject of study. Emerging evidence points to their role not only being cyto-protection of the parasite, as they are also implicated in regulating parasite virulence. In undertaking their roles, heat shock proteins operate in networks that involve not only partners of parasite origin, but also potentially functionally associate with human proteins to facilitate parasite survival and pathogenicity. This review seeks to highlight these interplays and their roles in parasite pathogenicity. We further discuss the prospects of targeting the parasite heat shock protein network towards the developments of alternative antimalarial chemotherapies.

Ionic Liquids: A Versatile Medium for the Synthesis of Six-membered Two Nitrogen- Containing Heterocycles

Due to special properties of ILs (ionic liquids) like their wide liquid range, good solvating ability, negligible vapour pressure, non-inflammability, environmentfriendly medium, high thermal stability, easy recycling and rate promoters etc. they are used in organic synthesis. Therefore, ionic liquids have attracted the attention of chemists and act as a catalyst and reaction medium in organic reaction with high activity. There is no doubt that ionic liquids have become a major subject of study for modern chemistry. More publications in the field have been observed each year, although there is some evidence that this is beginning to plateau at approximately 3500 papers each year. They have been the subject of several major reviews and books, dealing with different applications and aspects of their behavior. Highly efficient methods are explored for the preparation of six-membered two nitrogen-containing heterocycles with the application of IL as a catalyst and reaction medium from 1893 to 2018.

Mechanical Performance of Eco-Friendly Concretes with Volcanic Powder and Recycled Concrete Aggregates

At present, reducing the environmental impact of the construction industry is a major subject of study. In terms of the use of recycled concrete aggregates (RCA), most recently conducted studies have shown that the use of a limited percentage of those aggregates does not significantly affect the properties of concretes. This work analysed the mechanical properties of medium-strength concretes with a high contribution to sustainability, where cement and natural coarse aggregates (NCA) were partially replaced by volcanic powder (VP) and RCA, respectively. Three mixing ratios of VP replacement were tested in concretes without RCA and concretes with 30% RCA replacing NCA. Results show that when VP is used without RCA, up to 10% of the cement can be replaced by VP without a significant loss in the mechanical properties. When a combination of 5% VP and 30% RCA is used, the weakness of the recycled concrete is strengthened, obtaining stronger concretes than a control concrete with no recycled materials. Finally, the greenhouse gas assessment showed that the simultaneous incorporation of VP and RCA reduces CO2 emissions produced in the manufacture of concrete by up to 13.6%.

Topology optimization and Monte Carlo multithreading simulation for fault-tolerant nanoarrays

Nanocomputation based on emerging devices is becoming a major subject of study as a possible alternative to CMOS. These new technologies are highly defective due to the immaturity of the processes. It is extremely important then for both the technologists and the application engineers to have feedbacks on the impact on the circuit of such defectivity. The current scenario, though, evidences a complete lack of algorithms and tools for analyzing these kinds of circuits fault tolerance as well as for designing defect-tolerant circuits. This paper presents an unprecedented CAD ensemble. I) FaTToR, an algorithm for optimizing nanoarray-based circuits tolerance to defects. II) ToPoliNano based on a multithreading Monte Carlo switch-level simulation engine, a CAD for thoroughly analyzing the circuit defect tolerance against defect distributions derived by fabrication processes. Results are demonstrated in terms of output error rate and yield for nanoarray-based circuits of medium complexity. Several defect distributions are used as inputs for both FaTToR optimization and ToPoliNano validation. Our contributions represent a fundamental step forward both in terms of design automation methodology and in terms of specific feedbacks on the technology here studied. The approach is general and can be adopted to several other emerging technologies based on regular fabrics

Non-linear vibration analysis of hard rock TBMs with regenerative and stick–slip effects

The significant vibration caused by hard rock tunnel boring machines (TBMs) increases structural damage and reduces excavation efficiency and therefore has become a subject of major study within the tunnelling process. A two degrees-of-freedom model that accounts for axial and torsional vibrations that are coupled through the disc cutter–rock interaction is established in order to qualitatively analyse the complicated dynamic behaviours of the TBM system. Introducing a regenerative cutting effect into the cutter–rock interaction laws results in three interaction modes which are formulated based on the Colorado School of Mines (CSM) model. The regenerative effects and the friction caused by axial stick–slip motion are the sources responsible for the TBM self-excited vibration, of which the dynamics are described by state-dependent delay differential equations (DDEs). The DDEs are linearised and discretised into piecewise ordinary differential equations (ODEs) by using the semi-discretization method. Based on the Floquet theory, the stability limits of a TBM system are obtained, showing that the stable lobes are intermittently distributed in the operational parameter space. The parameter regime corresponding to the practical tunnelling is unstable, indicating that the vibrations of TBMs are easily excited by disturbances and never vanish in practical tunnelling. The axial vibration of TBMs with regenerative and stick–slip effects experiences a subcritical Hopf bifurcation, when the TBM goes from unstable to stable parameter regimes. The stick–slip effect suppresses the vibrations, which would otherwise increase without limit until cutter bounce appears if only the regenerative effect is considered. It is found that both the amplitude and the frequency of the axial stick–slip vibration increase with the increase in the steady advance velocity. The predicted axial stick–slip vibration and its amplitude in this investigation are both in good agreement with the observations obtained from a practical tunnelling project. This study provides reasonable insight into the vibration mechanism of TBMs and serves as a basis for choosing proper operational parameters in a practical project to achieve smooth and efficient tunnelling.

TIME AS A METAPHYSICAL DILEMMA: JOSE LUIS BORGES’ TREATMENT OF THE NATURE OF TIME IN HIS SELECTED WORKS

The concept of time, which has been a major subject of study in various fields, defies a neat definition. Many scholars have failed to define it in a manner applicable to all fields. Generally, time can be defined as the unlimited continued progress of existence and events in the past, present and future, regarded as a whole. It is a measure in which events can be ordered from the past through the present into the future. Some schools of thought deny the existence of time. They argue that the present is undefined and indefinite; and the future has no reality except as present recollection. In some of his works, Jose Luis Borges (1899–1986) describes time in a linear manner, that is to say, that humans experience time as a series of present moments, one following the other. The past and the future both exist nowhere but in the human mind. Borges seems to agree with the notion that time is but a figment of the mind. In other stories, his perception of time is circular. Thus, the focus of the current article is on time, which is a metaphysical dilemma, and Borges’ treatment of the nature of time in his selected works.