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The Impact of Environmental Factors on the Amount of Nitrates and Nitrites in Different Types of Soils and Ways of Their Utilization

Abstract

Despite the last decade considerable advances in the study of nitrate and nitrite pollution of soil, there are still some gaps in research related to neglecting or ignoring the role of soil in the food chain and its effects on upper trophic units. The article presents the results of a study on the impact of air and soil humidity and temperature, as well as soil type and utilization on the amount of nitrates and nitrites in the soil solution at the end of vegetation period. It was proved that statistically significant impact on the amounts of residual nitrate and nitrite ions was caused by the temperature and moisture of soil, its type, and the specific properties of the crops grown.

Open access
Implementing Interactive Teaching Methods for 9th Grade Organic Chemistry Classes

Abstract

One of the main challenges facing the current educational system is creating conditions suitable for academic skill development that allow students to navigate and adapt to today’s modern society, such as locating relevant information quickly as well as effectively utilizing innovations. We can achieve this objective by using interactive teaching methods. These methods take into account the contemporary issues and changing priorities - from the general content building for the courses to independent, student-centered cognitive activities.

The propose of this paper is to present tested and proven interactive methods for Grade 9Organic Chemistry classes. These methods significantly improve the quality of teaching and the students’ interest in the subject.

Open access
Interaction of 1,2-Alkadienephosphonic thioesters with sulphenyl- and selenenylbromide

Abstract

The reactivity of thioesters of 1,2-alkadienephosphonic acids toward sidphenyl- and selenenyl bromides has been investigated.

Open access
Mazer’s theory application in Bi4Ge3O12:V

Abstract

The recent development of coherent light amplifiers and oscillators, now generally referred to as optical masers “or lasers,” has made feasible a host of new uses and applications of electromagnetic wave energy in the optical portion of the spectrum. Furthermore, the high degree of monochromaticity obtainable from an optical maser makes it a useful tool for spectroscopic investigations as well as for stimulating various types of chemical and physical reactions. The effect of vanadium doping transforms Bi4Ge3O12 single crystals into optical maser. This result can be observed after thermoluminescence at 556 nm.

Open access
Morphostructure of the Sakar and Strandzha Mountains

Abstract

The Sakar and Strandzha Mountains are disposed in the South-East end of the Balkan Peninsula (on the both sides of the Bulgarian-Turkish boundary). They belong to the southeastern margin of the Bulgarian continental microplate. They are limit from North Thracian morphostructural zone to the North, the East Thracian morphostructural zone to the South and the Rhodopean morphostructural zone to the West. The observed mountain territory builds the Sakar-Strandzha morphostructural zone. It is divided by Sakar Dervent and Strandzha morphostructural areas. Every of them include morphostructural regions. They are composed by numerous Late Pleistocene-Holocene dome-like morphostructures. The relics from the Post Early Pleistocene concentric morphostructures are distributed in the entire zone. They were determined some archer and concentric Holocene mountain morphostructures.

The regional seismic activity (during the last 50 years) outlines three parts of the Sakar-Strandzha morphostructural zone. The western one - the Sakar part is moderate seismic active. The centred - Dervent part is practically seismic „calm“. The eastern one- Strandzha part show a very intensive seismicity. It can by given right in a future (after the necessary investigations) to divide the zone in three areas.

Open access
Nutritional status in short-term overtraining boxers

Abstract

The diet is essential to the recovery process in athletes, especially those undergoing intensive training. The continuous imbalance between loading and recovery leads to development of overtraining syndrome. The purpose of this study was to establish the changes in the nutritional status of short-term overtrained athletes. Twelve boxers from the team of National Spoils Academy Sofia, Bulgaria during their preparation for the National Championship 2016 were studied. The measurements were conducted three times.in the beginning of preparation (T1), 22 days later (2) and 10 days after (32 days after first measurement), in the beginning of the recovery period, one week prior the competition (T3).The measurements included basic anthropometric data, overtraining questionnaire RESTO-Sport and nutrition questionnaire, plasma concentration of testosterone and cortisol.On the data of dietary survey the percent proportion and the amount of daily consumed proteins, fats and carbohydrates were defined and the energy intake of the tested athletes was calculated. According to the RESTO-Sport a significant decrease in the ratio stress/recovery was observed in the period with the heaviest training load T2, and an increase was estimated in the pre­competition recovery period T3. It was found a typical for the overtraining syndrome decrease in the concentration of testosterone and the ratio of testosterone/cortisol in T3. In some respondents a reduction in carbohydrates and proteins intake was observed in T2 and especially in T3, which correlates with the hormonal changes. In this work the diet changes was discussed as a possible consequence and/or a cause of the overtraining syndrome.

Open access
The regional approach and regional studies method in the process of geography teaching

Abstract

We define the regional approach as a manner of relations among the global trends of development of the “Society-man-nature” system and the local differentiating level of knowledge. Conditionally, interactions interlace under the influence of the character of Geography as a science, education, approaches, goals and teaching methods.

Global, national and local development differentiates in three concentric circles at the level of knowledge. It is determined as a conception of modern, complex and effective mechanism for young people, through which knowledge develops in regional historical and cultural perspective; self-consciousness for socio-economic and cultural integration is formed as a part of the. historical-geographical image of the native land. This way an attitude to the. native land is formed as a connecting construct between patriotism to the motherland and the same in global aspect.

The possibility for integration and cooperation of the educative geographical content with all the local historical-geographical, regional, profession orientating, artistic, municipal and district institutions, is outlined.

Contemporary geographical education appears to be a powerful and indispensable mechanism for organization of human sciences, while the regional approach and the application of the regional studies method stimulate and motivate the development and realization of optimal capacities for direct connection with the local structures and environments.

Open access
Synthesis and properties of N-alkyl(phenyl)amido-O-methyl-1,2-alkadienephosphonates

Abstract

The synthesis of the titled compounds has been described. Their reactivity towards electrophilic and nucleophilic reagents has been investigated.

Open access
Assessment of Alder Tree Bark Potential as a Renewable Source of Proanthocyanidins in Latvia

Abstract

With the purpose to assess potential of alder tree bark as a renewable source of bioactive polyphenolic compounds, antioxidant properties of hydrophilic extracts and proanthocyanidins (PAC) isolated from bark of two alder species (grey alder and black alder) growing in Latvia have been examined employing two test systems, ABTS●+, DPPH assays. In the tests the high free radical scavenging capacities of the PAC were demonstrated. The polyphenolic nature of the bark PAC opens the possibility of its application as food additive. The PAC has good potential as an antioxidant for mayonnaise.

Open access
Comparison of Paraffin and Diesel Oil as Cultivation Medium Supplements for Preparing a Hydrocarbon-Degrading Bacterial Biomass

Abstract

The effect of liquid paraffin and diesel oil as nutrient amendments for hydrocarbon-degrading bacteria was compared. Different parameters were analyzed - optical density of bacterial suspension, oxygen consumption by biomass, morphology of bacteria, etc. In some experiments the paraffin was more preferable for microorganisms, but in other tests the results for both substances were similar. The influence of the comparable substances strongly depends on cultivation conditions.

Open access