Cytokinins, growth, flower and fruit formation in Vitis vinifera

Investigations were carried out on content and changes of the endogenous cytokinins in roots, buds, shoots, leaves, inflorescences and clusters of Vitis vinifera during bud burst, prior to anthesis, during full bloom, growth of the berries to 8-12 mm, ripening of the grapes, during leaf-fall and the period of relative rest. In order to obtain plants, differing in growth, flower and fruit formation, half of the vines were treated with CCC prior to bud burst. Consequently, the growth of the treated plants was inhibited by 12.6%, the number of the inflorescences was increased by 37.9%, the number of the clusters by 39.2% and the yield of the grapes by 34.1%.The plants showing inhibited growth and stimulated flower and fruit formation contain for all the phases investigated more cytokinins compared to the control: roots 0.021 1-1.g/g fresh material or 10.2%, buds 0.023 11g/g or 17.3%, shoots 0.040 p.g/g or 34.2%, leaves 0.024 ,ug/g or 9.8%, inflorescences and clusters 0.05 1-ig/g or 22.0%. Different amounts of cytokinins were established in the individual parts of ripe berries (skin, seeds and pulp).Cytokinine, Wachstum, Blüten- und Fruchtbildung bei Vitis viniferaEs wurden Untersuchungen über den Gehalt und die Änderungen der endogenen Cytokinine in den Wurzeln, Knospen, Trieben, Blättern, Blüten und Trauben von Vitis vinifera während des Austriebes, vor der Blüte, während der Vollblüte, des Beerenwachstums bis auf eine Größe von 8-12 mm, während der Traubenreife, des Blattfalles und der relativen Ruhe durchgeführt. Hierbei wurden Pflanzen verwendet, die sich in ihrem Wachstum sowie der Blüten- und Fruchtbildung unterschieden. Zu diesem Zweck wurde ein Teil der Reben vor dem Austrieb mit Chlorcholinchlorid (CCC) behandelt, wodurch das Längenwachstum um 12,6% verringert, die Anzahl der Blüten dagegen um 37,9%, die der Trauben um 39,2% und der Ertrag um 34,1 % erhöht wurden.Die Pflanzen mit gehemmtem Längenwachstum und geförderter Blüten- und Fruchtbildung enthielten im Durchschnitt mehr Cytokinine als die Kontrollpflanzen, u. z.: Wurzeln 10,2%, Knospen 17,3%, Triebe 34,2%, Blätter 9,80/o, Blüten und Trauben 22,0 %. Auch in Samen, Fleisch und Haut reifer Beeren wurden unterschiedliche Cytokininkonzentrationen festgestellt

Structure of Motivation for Training in Engineering Specialties

This article researches the structure of motivation for training in engineering specialties as well as the satisfaction from it. It analyses the main factors that form students’ motivation for training and the interrelationships between them. A comparative analysis of the state of the motivational structure is carried out of the opinions of both lecturers and students in engineering specialties, taking into account the similarities and differences between them. The article identifies the specific factors that form the motivation for the students in the aforementioned specialties, the problems in their training, and gives guidelines for their overcoming in order to improve the quality of training. The results of the research would contribute to raising the interest in training in engineering specialties, attracting and retaining motivated learners, and meeting the growing shortage of engineers on the labour market. This work is licensed under a&nbsp;Creative Commons Attribution-NonCommercial 4.0 International License.</p

Opportunities to Achieve a Sustainable Restaurant Business

This report examines the place of restaurant business in the tourism system and its importance in the formation and realization of the tourist product. Due to its leading role in tourism, opportunities are being sought to apply new tools and methods to achieve sustainable development, including reducing its harmful impact on the environment and creating new, more favourable habits for consumers. There is a study of good practices in the world and their potential application in Bulgarian catering establishments as possible ways to achieve sustainable restaurants. In addition, a survey is conducted among potential users of restaurant services to determine their attitude and role in achieving sustainable results. This work is licensed under a&nbsp;Creative Commons Attribution-NonCommercial 4.0 International License.</p

Моделиране на устойчивостта на колесни мобилни роботи по крен и тангаж

This article discusses the stability of wheeled mobile robots on roll and pitch, depending on their geometric proportions, as well as the forces acting on them. A dynamic model of this type of robot is built, based on the principles of kinetostatic. The influence of the parameters of the model on the roll and pitch stability has been studied. Coefficients of stability have been introduced. The dynamic model is built in such a way that it is possible to determine intervals with values of the parameters at which roll and pitch stability is guaranteed

Изследване на влиянието на параметрите на движението върху к.п.д. на правотоков двигател за колесен мобилен робот

The thematic is in the engineering (mechatronics) branch, with application in the mobile robotics. In the article have been examined: the mechanical energy at motion and its corresponding electrical consumption, as they define the energy effectiveness for the mechatronics system of a vehicle. There have been analysed dependencies, defined by the physics, in order to find out the demands, imposed on the construction "battery, electrical motor, gearing and drive wheels". The goal criterion is the achieved mileage with a single battery charge, which is determined by the dependencies "electrical consumption versus torque versus speed" at any actual motor type. The robot's dynamics parameters (weight, friction at movement, terrain slope, maximal speed and acceleration) appear as input data. Combinations between model parameters have been made, in order to be determined the optimal energy indicators as well as to choose the appropriate direct- current motor. This research uses a relatively small set of empirical physics coefficients and it can be used as an effortless methodology in some lecture notes on the mechatronics of a small wheeled mobile robot

Управление на колесен мобилен робот при следене на зададена траектория

В статията са изследвани проблемите на устойчивост при движение на четири-колесен мобилен робот по зададена траектория. Обект на изследването е колесен мобилен робот с предни завиващи и задни задвижващи колела по схема Акерман. Направена е симулация, базирана на bicycle математичен модел, в която се изчисляват надлъжната и напречната устойчивост. От симулацията се вижда че ускоренията не надвишават пределните стойности гарантиращи устойчивостта на робота по време на движението по зададената траектория.In the article, the problems of stability during movement of a four-wheeled mobile robot along a set trajectory are investigated. The object of the study is a wheeled mobile robot with front turning and rear driving wheels according to the Ackerman scheme. A simulation was made based on a bicycle mathematical model, in which the longitudinal and transverse stability are calculated. The simulation shows that the accelerations do not exceed the limit values guaranteeing the stability of the robot during the movement along the set trajectory

Broad neutralization of SARS-related viruses by human monoclonal antibodies

Broadly protective vaccines against known and preemergent human coronaviruses (HCoVs) are urgently needed. To gain a deeper understanding of cross-neutralizing antibody responses, we mined the memory B cell repertoire of a convalescent severe acute respiratory syndrome (SARS) donor and identified 200 SARS coronavirus 2 (SARS-CoV-2) binding antibodies that target multiple conserved sites on the spike (S) protein. A large proportion of the non-neutralizing antibodies display high levels of somatic hypermutation and cross-react with circulating HCoVs, suggesting recall of preexisting memory B cells elicited by prior HCoV infections. Several antibodies potently cross-neutralize SARS-CoV, SARS-CoV-2, and the bat SARS-like virus WIV1 by blocking receptor attachment and inducing S1 shedding. These antibodies represent promising candidates for therapeutic intervention and reveal a target for the rational design of pan-sarbecovirus vaccines