Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

Supercritical fluid extraction is a rapid, selective, and environmentally friendly method of particular interest in the extraction of essential oils from plants and herbs. Curcuma zedoaria is a member of the Zingiberaceae family widely cultivated in India, China, and Southeast Asia, including Vietnam. This study examined the chemical composition and antimicrobial activity of essential oils from the leaves and rhizomes of C. zedoaria from Vietnam obtained via supercritical fluid extraction. The main compounds of leaf essential oil were iso-borneol (31.2%), β-elemene (14.7%), β-caryophyllene (11.4%), 1,8-cineole (9.7%), and caryophyllene oxide (5.9%). In rhizome essential oil, 1,8-cineole (41.7%), β-elemene (13.6%), curzerenone (12.3%), camphor (10.2%), and germacrene B (5.2%) comprised the main compounds. The essential oils from C. zedoaria leaves and rhizomes displayed antimicrobial activity against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus cereus, and Candida albicans, with minimum inhibitory concentration values ranging from 100–400 µg/mL. Thus, our results support the need for further investigation of C. zedoaria essential oils as a potential source of antimicrobial agents.

In today's world, electronic shopping through various hardware has been developed to a great extent. Cellphones can help in to provide knowledge, course contents, interact with others and remote purchase. One of the necessities that plays an important role in today's chaotic environment is the concept of e-commerce. Despite the newness of this concept, e-commerce has made tremendous progress and especially recently in Iran, there has been an increase in its tendency, but on the other hand, since the goods in e-commerce are not tangible like in traditional commerce, it needs to follow a different approach. The current research is an applied research that examines the concepts of e-commerce, e-shopping, marketing mix and the relationship between them. The results showed that among all factors (independent variables), Product had the highest impact on customers' purchase intentions.

The aim of the research is to forecast the suitable suppliers for construction project using machine learning techniques. Firstly the librarian studies were conducted and research gap is extracted. Then innovation was determined. Based on the innovation a model for suitable supplier forecasting for construction project using machine learning techniques were provided. The model includes 12 entry variables and 1 output variable that include supplier performance. The model using 2 algorithm of artificial neuron network and support vector machine were conducted and the most influencing factors were determined using decision tree algorithm. The general comparison between artificial neuron network and support vector machine indicate the better performance of artificial neuron network based on decision tree. Based on decision tree results we can say that the supplier company income is considered as most important variable. The order change cost variable play the separator role in lower level. The life variables of companied and guarantees after company income and change cost of order play the main role.

Research aimed to reveal the character of the links between main modern trends in the economy and society and the development of tourism as one of the sectors of the Russian economy, on the one hand, and the type of human activity, on the other. In order to realize this goal, the main trends of the modern Russian economy were identified: economic crisis caused by pandemic coronavirus; rapidly developing digitalization of economy; the growing influence of ecological component on economic development and the increasing role of customer orientation in providing competitive positions of business. The study of trends in tourism, based on the use of methods of statistical analysis, confirmed the hypothesis that tourism is the sphere in which they are most clearly manifested. In particular, it concerns the following regularities: tourism as a branch of the Russian economy has suffered the most because of the economic crisis caused by pandemic coronavirus; tourism is the sector of the economy in which digitalization penetrates most actively; natural resources of Russia create boundless possibilities for ecological tourism development; client-oriented approach in tourism is not a declared principle, but a real business philosophy in modern conditions; increasing demands of Russian tourists for safe.

The development and implementation of the latest technologies allow achieving competitive advantages in the global market and open up a wide range of prospects in various fields of activity. High risks and significant initial investments have predetermined the need to develop the most accurate methods for assessing the effectiveness of innovations. Traditional methods of investment assessment allow analyzing the economic component of these projects but do not consider specific risks that have a predominant impact on the successful result of financing. The study shows the need for an individual approach to assessing the effectiveness of each innovative project implementation, which should take into account its social significance in conjunction with maximizing economic benefits. Calculations that allow obtaining a single criterion for choosing the most optimal variant of the project implementation are presented. Recommendations on the organization of effective deployment of the 5G network in the Russian Federation are given in the study's conclusion.

Wireless sensor networks (WSN) and radio frequency identification (RFID) are base technologies employed in decentralised dynamic environments. In the hybrid network formed by integrating RFID and WSN, RFID data can be used applying WSN protocols for multi-hop communications. However, RFID data contain excessive duplication, which increases time delay and energy consumption, resulting in wastage of different resources. There exist four popular RFID–WSN integration architectures: hierarchical RFID-sensor topology, network RFID-sensor topology, reader-sensor nodes topology, and mixed topology. In this paper, we propose a new plan for a WSN–RFID integrated network. The entire network is divided into clusters, and the clustering hierarchical routing algorithm is employed to send data from the head nodes to the base station. Further, we propose two algorithms to overcome redundant data on the hybrid network. Our simulation results demonstrate that the proposed method reduces redundant data and processing time compared with existing methods.

The article is devoted to the assessment of the impact of air transport on the development of the tourism industry. It has been established that air carriers around the world provide a significant share of international tourist trips and are dependent on fluctuations in tourist demand. It has been determined that the understanding of the need to study the degree of interdependence between the tourism and aviation business transforms traditional approaches to the study of tourism and aviation transport. The analyzed functional links between travel companies and airlines allowed asserting the formation of a specialized system, the logistics principles of which will enable people to maximize their mobility potential in the modern globalized world. It has been proved that the development of air transport becomes a decisive factor in the development of tourism, its driving force. For effective joint activities of airlines with tourist enterprises, it is necessary to develop such ways of their interaction that will allow them to function in a coordinated manner within the framework of a single chain of providing tourist services.

The focus of the study is the investigation of terminological foundations and the development of practical recommendations for assessing the effectiveness of hydrocarbon inflow stimulation at the final stage of field development. The authors refer to scientific works on the issues of company performance. The paper provides substantiation and improvement of methodological grounds with respect to assessing the effectiveness of gas inflow stimulation works. A classification and analysis of prominent Russian and foreign methods are provided and their issues are identified. As a result, the work refines the methodology for assessing the effectiveness of work at the drilling enterprise. The authors' comprehensive approach to assessing the effectiveness of inflow stimulation works, which allows for obtaining interrelated performance assessments, is proposed.

There are many ways to send and receive an electronic message, but SMS is more popular and nowadays used for one time password (OTP) as a part of authentication in many web applications, internet of things (IoT) access, password reset, mobile banking (M-banking), etc. Therefore, we must know how the protocol works and about its security. This protocol is designed to manage federatively (i.e., the mobile network is managing partially by many independent operators and it doesn’t need to have a central operator for the whole network. Also, many independent centrally managed networks can connect together to make a bigger network). We reviewed SMS protocol and its network structure, message structure, network entities, entities’ connection, and some security-related issues. Finally, this protocol is evaluated if it can provide Identification, Authentication, Integrity, Nonrepudiation, Confidentiality, and Availability.

Introducción: La capacitación de los profesionales egresados de las carreras de las ciencias de la salud es necesaria para las nuevas funciones que cumplirán una vez que inicien su vida laboral. En los cursos introductorios se imparten temas priorizados en los diferentes programas de salud pública para mantener y mejorar los indicadores alcanzados.Objetivo: Caracterizar las actividades de superación profesional y capacitación impartidas en los cursos introductorios por todas las universidades de ciencias médicas del país a los profesionales egresados de las carreras de las ciencias de la salud.Métodos: Se realizó un estudio descriptivo sobre las actividades de superación profesional y capacitación impartidas como parte indispensable del componente docente en los cursos introductorios. El universo estuvo constituido por 25 409 personas a capacitar en los temas de los cursos introductorios del 2017 al 2020. La muestra estuvo constituida por 24 801 profesionales.Resultados: Se capacitaron en todo el país 24 801 egresados de las carreras de las ciencias de la salud en los tres cursos introductorios impartidos desde 2017 al 2020, del primer nivel de atención de salud 19 599 profesionales y del segundo nivel 5209.Conclusiones: Cuba cuenta con una elevada cantidad de recursos humanos capacitados en diferentes aristas del conocimiento para enfrentar las principales causas de morbimortalidad y para lograr los indicadores favorables que hoy muestra.