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The study focuses on waste management and sampling practices carried out in two large Baltic cities: Riga (Latvia) and Tartu (Estonia). Even though waste collection schemes are not at the same centralisation level in the two municipalities, certain similarities can be observed in waste collection, management and sampling processes. Governed by provisions of Council Directive 1999/31/EC of 26 April 1999 on the landfill of waste, general national waste treatment legislation, and the national waste management plans, waste management practices in Latvia and Estonia are moving towards minimalisation of waste landfilling and maximalisation of waste inclusion into various recycling practices (use in waste biodegradation cells, bioreactors, different waste recycling facilities, in developing modern waste management supporting infrastructure, etc.). Therefore, waste management in two countries can be partly characterised as a vital element of emerging circular economy activities aimed at minimising landfill deposition of waste, hence, a more effective and permanent approach to sustainable waste management problems, on the one hand, and maximising the diversified use of waste in different branches of economy, hence, larger economic and social benefits. [ABSTRACT FROM AUTHOR]

This study focuses on overview and general economic viability evaluation of four types of portable electric generators: diesel and petrol internal combustion engines, batteries/accumulators and inverter systems (especially lithium polymer and lithium-ion battery systems), hydrogen fuel cell systems and combination (hybrid) of the latter. It does not include the rarely used, inefficient forms of energy conversion, such as steam turbines, as well as energy generators that are difficult to adjust with consumption and supply variations (variable forms of RES like wind and solar energy). The main targets of the study are battery/inverter systems, hydrogen fuel cell systems, and hybrid battery/inverter and hydrogen fuel cell systems, with hydrogen fuel cell systems being the thematic core. [ABSTRACT FROM AUTHOR]

The future of the European Union's (EU) gas sector and gas distribution systems in particular is under review as a necessity to move away from conventional natural gas is strictly outlined in its strategical energy framework. The main questions of future gas sector layout are largely related to gas decarbonization paths – whether they will include simultaneous transportation, distribution and storage of methane-based and non-methane based renewable gases or not. In general, this question is left for different Member States to decide, because as alternatives to it there are two options – decommissioning of all gas distribution and partially gas transportation and storage systems on the one hand and total replacement of existing gas transportation system with brand new hydrogen transportation and distribution system on the other. The first option leaves only liquified renewable gases (including, hydrogen) that are transported via truck and the second – pipeline transportation and distribution only for hydrogen, limiting methane-based renewable gases to road transportation solutions only. The Latvian gas distribution system is also facing imminent transformation in foreseeable future; thus, at the moment its sustainability priority is the maintenance of the existing system in a safe and secure manner by improving it in accordance with technical necessities and immediate customer requests. The current research shows two sides of gas distribution system priorities in Latvia – its maintenance and development trends prior to fundamental transformations of gaseous fuel transition and general transitional challenges laying ahead. [ABSTRACT FROM AUTHOR]

Hydrogen has been widely recognised as a versatile and environmentally-friendly energy carrier, with a broad range of potential applications across various sectors. The abundance of hydrogen in the universe and its high energy content makes it an attractive alternative to conventional fossil fuels. Moreover, the utilization of hydrogen does not produce greenhouse gases or other pollutants that contribute to air pollution and climate change. In recent years, there has been a growing interest in developing and deploying hydrogen technologies for a sustainable energy future. This paper provides an in-depth exploration of the potential of hydrogen as a clean energy source in different sectors, such as transportation, energy storage, power generation, industry, buildings, maritime transport, and aviation. The aim of the paper is to provide an overview of the current state of hydrogen applications in Europe and the Baltic States, including examples of ongoing projects and initiatives, and to assess the advantages and disadvantages of hydrogen technologies in different sectors. The main results of the paper highlight that hydrogen has the potential to significantly reduce greenhouse gas emissions and achieve carbon neutrality targets. However, the deployment of hydrogen technologies also faces various challenges such as high production costs, lack of infrastructure, and safety concerns. The tasks of the paper are to provide an insight into the potential of hydrogen, identify the challenges and limitations, and highlight ongoing research and development efforts in this field. The paper concludes that the widespread adoption of hydrogen technologies is a long-term goal that requires the cooperation of various stakeholders and the development of innovative and cost-effective solutions. Despite the challenges, the current state of hydrogen applications and ongoing projects in Europe and the Baltic States demonstrate that hydrogen has the potential to play a significant role in the transition to a sustainable and low-carbon future. [ABSTRACT FROM AUTHOR]

This article provides a review of the construct of attention from a non-traditional standpoint. Attention is conceptualized by focusing on the categorical concept of the diagnosis of attention-deficit hyperactivity disorder, large-scale brain network models of functional neuroanatomy, and implications for understanding lateralized hemispheric brain organization. Cortical systems are multifunctional, with certain degrees of specialization, but no cortical region or network supports only one, specific, isolated cognitive process, such as attention. Future implications for clinical practice must focus on connectivity patterns rather than the idea of "domains" or "constructs" when considering attention and other cognitive processes. This has significant implications for the future of neuropsychological assessment and intervention.