The economy of Latvia lags behind economically developed nations approximately fourfold in terms of labour productivity in the tradable sector, which is the key constituent of a modern economy, thereby affecting future sustainable development in the entire country, including the rural areas. The economic backwardness is characteristic of the entire Central and Eastern Europe. This is the heritage of a communist regime that lasted for about half a century and the economic system termed a (centrally) planned economy or a command economy. However, such a term for the communist-period economy is not correct, as it does not represent the purpose it was created for. Accordingly, the paper aims to assess the effect of the communism period on the economic backwardness of the Central and Eastern European region of the EU. A planned economy that existed in all communist countries, with the exception of Yugoslavia, was not introduced to contribute to prosperity. It was intended for confrontation or even warfare by the communist countries under the guidance of the USSR against other countries where no communism regime existed, mostly Western world nations with their market economies. For this reason, it is not correct to term it a (centrally) planned economy or a command economy; the right term is a mobilised (war) economy. An extrapolation of a geometric progression for GDP revealed that during the half a century, Latvia as part of the USSR was forced to spend on confrontation with the West not less than EUR 17 bln. (2011 prices) or approximately one gross domestic product of 2011. The research aim of the paper is to assess the effect of the communism period on the economic backwardness of the Central and Eastern European region of the EU.

The economy of Latvia lags behind economically developed nations approximately fourfold in terms of labour productivity in the tradable sector, which is the key constituent of a modern economy, thereby affecting future sustainable development in the entire country, including the rural areas. The economic backwardness is characteristic of the entire Central and Eastern Europe. This is the heritage of a communist regime that lasted for about half a century and the economic system termed a (centrally) planned economy or a command economy. However, such a term for the communist-period economy is not correct, as it does not represent the purpose it was created for. Accordingly, the paper aims to assess the effect of the communism period on the economic backwardness of the Central and Eastern European region of the EU. A planned economy that existed in all communist countries, with the exception of Yugoslavia, was not introduced to contribute to prosperity. It was intended for confrontation or even warfare by the communist countries under the guidance of the USSR against other countries where no communism regime existed, mostly Western world nations with their market economies. For this reason, it is not correct to term it a (centrally) planned economy or a command economy; the right term is a mobilised (war) economy. An extrapolation of a geometric progression for GDP revealed that during the half a century, Latvia as part of the USSR was forced to spend on confrontation with the West not less than EUR 17 bln. (2011 prices) or approximately one gross domestic product of 2011. The research aim of the paper is to assess the effect of the communism period on the economic backwardness of the Central and Eastern European region of the EU.

The employment of people with disabilities has multidimensional aspects - economic, social, legal, human rights, discrimination, psychological, ethical and responsibility aspects - with different actors involved representing various kinds of interests. The European Union Disability Action Plan and Strategy specifies the objective of promoting the employment of people with disabilities in the open labour market. The employment of such individuals is not only an economic issue, but also an issue of social inclusion, poverty reduction, equal opportunity and socially responsible employment. Effective and fair use of human resources for national economic development requires a variety of support mechanisms, including regulatory frameworks, the active involvement of local municipalities, and measures taken by state institutions. Because of the different issues and the various actors with different interests involved, an integrated way has to be considered to analyse the employment factors and employment opportunities for people with disabilities. The purpose of this study is to explore and substantiate the possible scenarios associated with promotion employment opportunities for people with disabilities in Latvia. The research methodology employed for this study is based on the Analytic Hierarchy Process, and expert interviews are used to analyse the interests of all involved parties, in order to determine the best possible scenarios as to how to stimulate employment for people with disabilities. As a result, three scenarios to promote the employment of people with disabilities were developed. Although the results showed slight differences between the three scenarios, experts believe that the optimal scenario for promoting the employment of people with disabilities is the one in which the EU participates.

The employment of people with disabilities has multidimensional aspects − economic, social, legal, human rights, discrimination, psychological, ethical and responsibility aspects − with different actors involved representing various kinds of interests. The European Union Disability Action Plan and Strategy specifies the objective of promoting the employment of people with disabilities in the open labour market. The employment of such individuals is not only an economic issue, but also an issue of social inclusion, poverty reduction, equal opportunity and socially responsible employment. Effective and fair use of human resources for national economic development requires a variety of support mechanisms, including regulatory frameworks, the active involvement of local municipalities, and measures taken by state institutions. Because of the different issues and the various actors with different interests involved, an integrated way has to be considered to analyse the employment factors and employment opportunities for people with disabilities. The purpose of this study is to explore and substantiate the possible scenarios associated with promotion employment opportunities for people with disabilities in Latvia. The research methodology employed for this study is based on the Analytic Hierarchy Process, and expert interviews are used to analyse the interests of all involved parties, in order to determine the best possible scenarios as to how to stimulate employment for people with disabilities. As a result, three scenarios to promote the employment of people with disabilities were developed. Although the results showed slight differences between the three scenarios, experts believe that the optimal scenario for promoting the employment of people with disabilities is the one in which the EU participates.

The development of organic farming is determined by many factors. On the one hand, it is an increase in demand for food produced in this production system, on the other it is a subsidy system for organic farming under the CAP. The purpose of the article is a comparative analysis of the direction of changes in the development of organic farming in Poland and Latvia compared to the EU in the years 2000-2017. Information was analysed on the organic farming i.e. the area of organic crops, the number of certified farms and organic retail sales, based on FIBL data from the years 2000–2017. An analysis of the trend of changes in organic farming in Poland and Latvia indicates that the development of organic farming in both countries has clearly accelerated after their accession to the EU and after covering organic farming by the CAP support system. However, the case of Poland is definitely different from the trend of changes in organic farming in Latvia and in the EU, where both the number of organic farms and their area increased, with the simultaneous development of the organic food market. There are many indications that mistakes were made in the organic farming subsidy system.

The development of organic farming is determined by many factors. On the one hand, it is an increase in demand for food produced in this production system, on the other it is a subsidy system for organic farming under the CAP. The purpose of the article is a comparative analysis of the direction of changes in the development of organic farming in Poland and Latvia compared to the EU in the years 2000–2017. Information was analysed on the organic farming i.e. the area of organic crops, the number of certified farms and organic retail sales, based on FIBL data from the years 2000–2017. An analysis of the trend of changes in organic farming in Poland and Latvia indicates that the development of organic farming in both countries has clearly accelerated after their accession to the EU and after covering organic farming by the CAP support system. However, the case of Poland is definitely different from the trend of changes in organic farming in Latvia and in the EU, where both the number of organic farms and their area increased, with the simultaneous development of the organic food market. There are many indications that mistakes were made in the organic farming subsidy system.

This paper investigates the effect of separated exhaust expansion chamber parameters on pressure oscillations in spark-ignited internal combustion (IC) gasoline engines. It is known that exhaust expansion chambers are becoming increasingly more popular among both – original equipment (OE) and aftermarket equipment (AE) exhaust system manufacturers for performance-oriented motorcycles equipped with mainly single cylinder engines, but the companies are reluctant to reveal any detailed principles of operation of the mentioned expansion chambers. The subject of this research is the type of expansion chamber (separate) as used on performance-oriented motorcycles, particularly its’ effect on exhaust pressure pulsations as different chamber volumes, locations and passage sizes are tested. Time-dependent computational fluid dynamics (CFD) analysis was carried out in Solidworks Flow Simulation environment on a simplified exhaust header pipe model imitating engine operation at full load and steady speed. Honda CRF450R motorcycle engine was used as the example and fully defined using a 1D engine performance calculator software to determine the combustion chamber pressure and exhaust valve lift at any given crankshaft position. Volume flow rate of exhaust gasses at the header pipe inlet was calculated based on engine parameters and operating speed. The average pressure values with respect to physical time were measured and graphed across the header pipe inlet cross-section. Eight different header pipe and exhaust expansion chamber combinations were modelled, tested, and results compared at low, medium and high engine speeds. It was found that the presence of exhaust expansion chamber tends to dampen the amplitude and decrease the frequency of pressure oscillations generated at the opening of the exhaust valve(s). Observations show that the addition of an expansion chamber as per design of performance-oriented motorcycles helps to decrease the negative effect of engine tuning while also dampening the positive effect.

This paper investigates the effect of separated exhaust expansion chamber parameters on pressure oscillations in spark-ignited internal combustion (IC) gasoline engines. It is known that exhaust expansion chambers are becoming increasingly more popular among both – original equipment (OE) and aftermarket equipment (AE) exhaust system manufacturers for performance-oriented motorcycles equipped with mainly single cylinder engines, but the companies are reluctant to reveal any detailed principles of operation of the mentioned expansion chambers. The subject of this research is the type of expansion chamber (separate) as used on performance-oriented motorcycles, particularly its’ effect on exhaust pressure pulsations as different chamber volumes, locations and passage sizes are tested. Time-dependent computational fluid dynamics (CFD) analysis was carried out in Solidworks Flow Simulation environment on a simplified exhaust header pipe model imitating engine operation at full load and steady speed. Honda CRF450R motorcycle engine was used as the example and fully defined using a 1D engine performance calculator software to determine the combustion chamber pressure and exhaust valve lift at any given crankshaft position. Volume flow rate of exhaust gasses at the header pipe inlet was calculated based on engine parameters and operating speed. The average pressure values with respect to physical time were measured and graphed across the header pipe inlet cross-section. Eight different header pipe and exhaust expansion chamber combinations were modelled, tested, and results compared at low, medium and high engine speeds. It was found that the presence of exhaust expansion chamber tends to dampen the amplitude and decrease the frequency of pressure oscillations generated at the opening of the exhaust valve(s). Observations show that the addition of an expansion chamber as per design of performance-oriented motorcycles helps to decrease the negative effect of engine tuning while also dampening the positive effect.

The work presents foundations of the dynamics of the flat-parallel movement of a bridge agricultural unit in a horizontal with the kinematic method of its control (turning the wheels) by changing the position of one of its parts relative to the other. The analysis of assessment of the degree of impact of the scheme and parameters of the investigated agricultural tool upon its controllability and stability of movement is based on the amplitude and phase frequency characteristics. The mathematical models of the movement of the bridge agricultural unit are presented in a differential and an operator form of recording. Based on mathematical models, the calculated amplitude and phase frequency characteristics of the dynamic control system of the control impact, presented as the angular displacement of its half-frames ψ, are constructed for various parameters and operating modes. The constructed mathematical models, amplitude and phase frequency characteristics make it possible to assess the impact of the control parameter of the bridge agricultural unit, as well as its design and other parameters upon the controllability of the movement.

The work presents foundations of the dynamics of the flat-parallel movement of a bridge agricultural unit in a horizontal with the kinematic method of its control (turning the wheels) by changing the position of one of its parts relative to the other. The analysis of assessment of the degree of impact of the scheme and parameters of the investigated agricultural tool upon its controllability and stability of movement is based on the amplitude and phase frequency characteristics. The mathematical models of the movement of the bridge agricultural unit are presented in a differential and an operator form of recording. Based on mathematical models, the calculated amplitude and phase frequency characteristics of the dynamic control system of the control impact, presented as the angular displacement of its half-frames ψ, are constructed for various parameters and operating modes. The constructed mathematical models, amplitude and phase frequency characteristics make it possible to assess the impact of the control parameter of the bridge agricultural unit, as well as its design and other parameters upon the controllability of the movement.

There is a strong correlation between diet and mental health, and malnutrition can contribute to the development of various psycho-neurological diseases. Fatty acid profile plays an important role in the treatment of psycho-neurological diseases; therefore, the aim of the current study was to evaluate fatty acid profile in the diet of patients in three Latvian psycho-neurological hospitals. Latvian psycho-neurological hospitals submitted a detailed one-week menu. The information in the menus was processed using the Fineli program. Each menu identified the composition of fatty acids. The average fat concentration in different hospital menus ranged from 74.8 g to 96.1 g per day, where the concentration of saturated fatty acids ranged from 37.5 g to 47.7 g per day and the unsaturated fat concentration ranged from 35.9 g to 47 g per day. The n-3 PUFA content was consistent with the recommendations of a healthy individual, but it did not meet the needs of patients in a psycho-neurological hospital. The total eicosapentaenoic acid and docosahexaenoic acid concentration in the hospital menus ranged from 0.03 to 0.13 g, which was significantly lower than recommended, whereas LA and ALA concentration in hospital menus is close to optimal. The trans-fatty acids concentration in hospital menus did not exceed 2.5 g per day, with the exception of one day in hospital No. 2. The impact of diet on the treatment of psycho-neurological diseases in Latvian psycho-neurological hospitals has not been sufficiently assessed.

There is a strong correlation between diet and mental health, and malnutrition can contribute to the development of various psycho-neurological diseases. Fatty acid profile plays an important role in the treatment of psycho-neurological diseases; therefore, the aim of the current study was to evaluate fatty acid profile in the diet of patients in three Latvian psycho-neurological hospitals. Latvian psycho-neurological hospitals submitted a detailed one-week menu. The information in the menus was processed using the Fineli program. Each menu identified the composition of fatty acids. The average fat concentration in different hospital menus ranged from 74.8 g to 96.1 g per day, where the concentration of saturated fatty acids ranged from 37.5 g to 47.7 g per day and the unsaturated fat concentration ranged from 35.9 g to 47 g per day. The n-3 PUFA content was consistent with the recommendations of a healthy individual, but it did not meet the needs of patients in a psycho-neurological hospital. The total eicosapentaenoic acid and docosahexaenoic acid concentration in the hospital menus ranged from 0.03 to 0.13 g, which was significantly lower than recommended, whereas LA and ALA concentration in hospital menus is close to optimal. The trans-fatty acids concentration in hospital menus did not exceed 2.5 g per day, with the exception of one day in hospital No. 2. The impact of diet on the treatment of psycho-neurological diseases in Latvian psycho-neurological hospitals has not been sufficiently assessed.

The experiment was conducted to analyse the effect of fermented acid whey permeate on milk yield and composition in the lactating cows. Propionic acid bacteria and their metabolites have been used in the lactating cows feeding over decades, primarily to improve growth performance, feed conversation and milk production efficiency. Two groups of the lactating cows were arranged in the study: control group (n=50) and experimental group (n=50). Experimental group’s animals received 0.5 L of fermented whey permeate daily. Acid whey permeate was inoculated with the freeze-dried PS-4 (Propionibacterium freudenreichii subsp. shermanii, Chr.Hansen, Denmark) starter and fermented anaerobically for 48 hours at 20±2 ºC. Fat, protein, lactose and total solids concentration in acid whey permeate and fermented acid whey permeate was analysed by the standard methods, but propionic acid was detected by HPLC. Milk composition and quality indices were determined at the beginning of the study and each month during 6 months period. At the end of the study the feeding of fermented acid whey permeate was stopped, but milk composition and quality data were monitored additionally after one month. Milk fat, protein, lactose, total solids, urea concentration and somatic cell count were analysed by a near infrared spectroscopy. The variability in milk composition and quality data across trial was greater in the experiment group than in the control. Milk fat and somatic cell count were significantly different (p is less than 0.05) than other studied parameters in the experimental group cows’ milk. Milk yield and lactose concentration were tended to increase during feeding of fermented acid whey permeate in the lactating cows without significant differences between control and experimental groups. Fermented acid whey permeate as feed supplement improves energy metabolism for dairy cows which results in the higher milk yield and fat concentration.

The experiment was conducted to analyse the effect of fermented acid whey permeate on milk yield and composition in the lactating cows. Propionic acid bacteria and their metabolites have been used in the lactating cows feeding over decades, primarily to improve growth performance, feed conversation and milk production efficiency. Two groups of the lactating cows were arranged in the study: control group (n=50) and experimental group (n=50). Experimental group’s animals received 0.5 L of fermented whey permeate daily. Acid whey permeate was inoculated with the freeze-dried PS-4 (Propionibacterium freudenreichii subsp. shermanii, Chr.Hansen, Denmark) starter and fermented anaerobically for 48 hours at 20±2 ᵒC. Fat, protein, lactose and total solids concentration in acid whey permeate and fermented acid whey permeate was analysed by the standard methods, but propionic acid was detected by HPLC. Milk composition and quality indices were determined at the beginning of the study and each month during 6 months period. At the end of the study the feeding of fermented acid whey permeate was stopped, but milk composition and quality data were monitored additionally after one month. Milk fat, protein, lactose, total solids, urea concentration and somatic cell count were analysed by a near infrared spectroscopy. The variability in milk composition and quality data across trial was greater in the experiment group than in the control. Milk fat and somatic cell count were significantly different (p<0.05) than other studied parameters in the experimental group cows’ milk. Milk yield and lactose concentration were tended to increase during feeding of fermented acid whey permeate in the lactating cows without significant differences between control and experimental groups. Fermented acid whey permeate as feed supplement improves energy metabolism for dairy cows which results in the higher milk yield and fat concentration.

An urgent problem is drying and processing of the wet dispersed waste, obtained in the production of food products, which can then be efficiently used as a fertiliser, for feeding livestock or as biofuel. A new design of a vibrating fluidised bed dryer has been developed, which, with low energy consumption, provides a pre-set productivity and the required final moisture content. The process of vertical oscillations of the body of a vibration dryer, together with the food waste contained in it, is analysed analytically, the necessary equivalent scheme is built, on the basis of which differential equations of the vertical oscillations of the body are compiled, their analytical solutions are obtained, and a numerical calculation is performed on a PC using the developed program.

An urgent problem is drying and processing of the wet dispersed waste, obtained in the production of food products, which can then be efficiently used as a fertiliser, for feeding livestock or as biofuel. A new design of a vibrating fluidised bed dryer has been developed, which, with low energy consumption, provides a pre-set productivity and the required final moisture content. The process of vertical oscillations of the body of a vibration dryer, together with the food waste contained in it, is analysed analytically, the necessary equivalent scheme is built, on the basis of which differential equations of the vertical oscillations of the body are compiled, their analytical solutions are obtained, and a numerical calculation is performed on a PC using the developed program. Rational parameters of the vibration dryer, providing vibroboiling of the mass of the food waste, have been determined: the body mass m = 250 ... 510 kg; the debalance mass md = 10… 15 kg; the number of revolutions of the debalance electric motor nd = 1950 ... 2650 rpm ∙ min ∙¹; maximum stiffness of the support springs Cₚ = 8∙10⁵ N∙m–¹; the diameter of the centre of mass of the debalances dd = 0.01 m. In addition, as a result of the thermophysical theoretical and experimental studies of the vibration drying process, the following optimal design and technological parameters of the vibration dryer were obtained: the heat transfer area Sₜ.ₚ.ₙ= 4.15 m²; the radius of the heating pipe rₜ= 0.1 m; the length of the heating pipe lₜ = 3 m; the number of heating pipes nₜ= 50; the heat transfer coefficient Kₚ= 2500; the final temperature of the dried waste tₒ₂ = 100 ºС.