55 research outputs found

    Forecasting bond returns using asymmetric regression and investment management

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    The first section of this research formulates the forecasting task important for managing investment portfolio as well as discusses certain statistical data. The second section is devoted to potential regressors frequently used to forecast risk premiums of bonds, this section extensively use the ideas presented in article [4]. The third section includes the research of asymmetry of relation between risk premiums and regressors. The fourth section is devoted to the investigation of applicability received results in practice

    Vibrations generator with a motion converter based on permanent magnet interaction

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    The paper deals with a new type of vibrations exciters whose operation is based on the forces developed by permanent magnets interacting between input and output members. Classification and some diagrams of vibrations exciters are presented. Mathematical models of one-dimensional vibrations exciters are set up. In cases when mean velocities of the magnets of input member and output member are equal and when velocity of an output member magnet is lower than that of an input member, dynamics is studied by means of approximate analytic methods. More complicated cases are studied by means of numerical methods. Estimated dynamic characteristics of the system, its established peculiarities and properties make it possible to apply the mentioned exciters to some technological processe

    Research of dynamics of rotary vibration actuators based on magnetic coupling

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    The article analyses a new type of a mechanical rotary oscillator – vibrator, the base of which is made of steady magnets. The scheme of a vibrator’s regulated power is submitted to excite the rotary oscillations of a turning frame. Some of the dynamical characteristics of a vibrator have been researche

    Research of dynamics of rotary vibration actuators based on magnetic coupling

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    The article analyses a new type of a mechanical rotary oscillator – vibrator, the base of which is made of steady magnets. The scheme of a vibrator’s regulated power is submitted to excite the rotary oscillations of a turning frame. Some of the dynamical characteristics of a vibrator have been researche

    Genetic structure of fragmented southern populations of African Cape buffalo (Syncerus caffer caffer)

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    peer reviewedBackground African wildlife experienced a reduction in population size and geographical distribution over the last millennium, particularly since the 19th century as a result of human demographic expansion, wildlife overexploitation, habitat degradation and cattle-borne diseases. In many areas, ungulate populations are now largely confined within a network of loosely connected protected areas. These metapopulations face gene flow restriction and run the risk of genetic diversity erosion. In this context, we assessed the “genetic health” of free ranging southern African Cape buffalo populations (S.c. caffer) and investigated the origins of their current genetic structure. The analyses were based on 264 samples from 6 southern African countries that were genotyped for 14 autosomal and 3 Y-chromosomal microsatellites. Results The analyses differentiated three significant genetic clusters, hereafter referred to as Northern (N), Central (C) and Southern (S) clusters. The results suggest that splitting of the N and C clusters occurred around 6000 to 8400 years ago. Both N and C clusters displayed high genetic diversity (mean allelic richness (Ar) of 7.217, average genetic diversity over loci of 0.594, mean private alleles (Pa) of 11), low differentiation, and an absence of an inbreeding depression signal (mean FIS = 0.037). The third (S) cluster, a tiny population enclosed within a small isolated protected area, likely originated from a more recent isolation and experienced genetic drift (FIS = 0.062, mean Ar = 6.160, Pa = 2). This study also highlighted the impact of translocations between clusters on the genetic structure of several African buffalo populations. Lower differentiation estimates were observed between C and N sampling localities that experienced translocation over the last century. Conclusions We showed that the current genetic structure of southern African Cape buffalo populations results from both ancient and recent processes. The splitting time of N and C clusters suggests that the current pattern results from human-induced factors and/or from the aridification process that occurred during the Holocene period. The more recent S cluster genetic drift probably results of processes that occurred over the last centuries (habitat fragmentation, diseases). Management practices of African buffalo populations should consider the micro-evolutionary changes highlighted in the present study

    Communication in decision making process. Case of Algirdas mechanized infantry battalion.

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    Decision making is one of the most important processes and factors, that is used in every organization, institution and even in the work of individuals daily. The decisions made, rightfully or wrongfully, may affect the end goal. One of these factors that let the decision making process to function smoothly is communication. Cooperation, exchange of information, different exchange types – these communication aspects make up a big portion of the decision making environment, which is directly associated with suitability of the decision and its benefits for the organization. The problem which is pointed out in this bachelors work is to find out whether the communication in Lithuanian Algirdas mechanized infantry battalion (AMIB) is effective in decision making. The object of the work – The rule of communication in the decision making process in the AMIB. The main goal is to give recommendations for problem solving after analysing the role of communication in the decision making process. In order to achieve the main goal, these tasks were made: 1) to analyse scientific sources of literature in the aspect of communication in decision making; 2) based on the comparative analysis of the scientific literature, to identify and determine the effective types and flaws of communication; 3) to analyse the role of communication in the decision making process in the battalion mentioned above and after identifying the problem areas, give improvement solutions. The third task is used as a goal in the empiric study and is divided in four tasks: 1) to evaluate the communication of the AMIB personnel in the process of decision making; 2) to determine the channels of communication in the AMIB; 3) to evaluate the effectiveness of communication in the AMIB; 4) to identify the communicational interferences in the AMIB. In order to accomplish the study, the comparative analysis of scientific literature was used, as well as methods of descriptive statistics, a questionnaire and data processing with “IBM SPSS statistics V23” programme were of great benefit. The study determined that: 1) communication in the mentioned battalion is not highly effective, has several flaws, such as poorly – timed information exchange and insufficient amounts of information given to the military officer which all leads to inability to solve problems and execute tasks. Several IT and workload related problems were found; 2) most common communication channels in the mentioned battalion are “eye to eye”, meetings, phone calls and e-mail. In reference to the material laid out in the theory portion of the work, these channels, while used in conjunction, perfectly complements each other and superbly fits in the work of the battalion

    Ultrasound Use in Prehospital Setting

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    Aim: To find out the peculiarities of the use of ultrasound diagnostics in the prehospital setting. Objectives: 1. To determine whether ultrasound usage is feasible in prehospital setting 2. To determine the accuracy of ultrasound diagnostics in prehospital conditions 3. To find out if performed point-of-care ultrasound changes patient management 4. To find out what difficulties are encountered in using ultrasound in pre-hospital conditions Methods: A systematic review and analysis of the literature was performed according to the PRISMA methodology. The searches were performed on PubMed, ScienceDirect, Cochrane, and WebOfScience electronic databases using keywords and their synonyms. Articles not older than 10 years were included in the review and selected according to pre-established inclusion and exclusion criteria. Results: After conducting a search in databases 1736 entries were found. After rejecting duplicates, reviewing article titles and abstracts, 95 publications were selected for full article analysis. After full-text analysis, 15 articles were included in the systematic review. Six articles examined the peculiarities of lung ultrasound examination, two - the use of ultrasound during resuscitation, all the remaining articles did not focus on a specific area. The vast majority (14/15) of the articles analyzed the accuracy of prehospital ultrasound by assessing sensitivity, specificity, positive prognostic value, negative prognostic value, or kappa consensus level. Conclusions: 1. Ultrasound examination of a patient is a suitable diagnostic method in prehospital conditions. 2. The accuracy of ultrasound diagnostics varies depending on the area being studied and increases with repeated examination during the patient's care period. 3. Ultrasound examination of the patient provides useful information about his condition, helps to make important decisions related to the patient's care and helps to avoid unnecessary or harmful interventions. 4. The most common obstacles are weather and environmental conditions, which make it difficult to access the patient optimally. Ultrasound examination is more difficult and the quality of the examination is lower in patients who weigh more. Recommendations: Given the benefits of diagnostics for the patient, ultrasound examination of patients is also recommended in the pre-hospital phase
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