363 research outputs found

    Affective Reactivity to Positive Daily Events in Adolescence

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    The experience of positive events is associated with increased positive affect (PA), which can beneficially impact physical and mental health outcomes of adolescents. This study investigated whether different types of positive events elicit different amounts of PA, and whether sex would moderate these effects. Participants were 136 adolescents (Mage = 13.03 years, 51.3% female). Results indicated that interpersonal and independent events predicted greater PA reactivity than non-interpersonal and dependent events, respectively. Sex did not moderate these effects. Furthermore, results indicated that interpersonal, dependent events were associated with the highest adolescent mean PA compared to any other combination of event types

    Computer Simulation to Optimize the VFA Alpha Prototype with a Hydraulic Piston Compressor and an Integrated Booster

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    The research has been supported by the European Regional Development Fund project "Competence Centre of Mechanical Engineering", contract No.1.2.1.1/18/A/008 signed between the Competence Centre of Mechanical Engineering and the Central Finance and Contracting Agency, Research No. 3.1 "Additional research and integra tion of the technology of hydraulic piston, aiming to develop and demonstrate economically efficient compressed natural gas smart commercial vehicle fuelling appliance". Our special gratitude to Gaspard Bouteau, PhD, Research Engineer, who conducted research in Engie Lab CRIGEN. Scientific co-authorship of the Laboratory of Materials for Energy Harvesting and Storage, ISSP UL has been supported by the Ministry of Economics of the Republic of Latvia, project LAGAS No VPP-EMINFRA- 2018/1-0003.Natural gas, including biomethane, is a sustainable alternative fuel. Widening compressed natural gas applications by now is restricted by weakly developed infrastructure. Hygen Ltd. works on "hydraulic piston"technology for natural gas and biomethane compressing, storing, delivering and discharging the storage cylinders by means of an innovative hydraulic boosting technology. Designing of the Vehicle Fuelling Appliance (VFA) demands to take into account thermodynamics and gas dynamics properties at fluid compression and motion. The present paper deals with theoretical characteristics and their link to test measurements regarding a particular VFA HYGEN+ Alpha prototype manufactured by Hygen Ltd.Izglītības un zinātnes ministrija VPP-EMINFRA- 2018/1-0003; European Regional Development Fund 3.1,1.2.1.1/18/A/008; Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART

    Prospects of Decarbonizing Industrial Areas in the Baltic States by Means of Alternative Fuels

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    This work has been supported by the National Research Programme, project “Trends, Challenges and Solutions of Latvian Gas Infrastructure Development” (LAGAS), No. VPP-EM-INFRA-2018/1-0003.All three Baltic States have reached good fi gures regarding the change in total greenhouse gas emissions from transport during 1990-2017. Particularly successful is Lithuania, showing a negative value of -2.7%. Latvia considerably lags behind Estonia (+15.1% vs. +1.5%). Amid the achievement of Latvian scientists, engineers and merchants, the authors point out the work of Lithuanian engineers who investigated how gaseous hydrogen affects the parameters of diesel internal combustion engine. Important to note that in the Baltic States, the activities of inland waterway vessels and the shunting locomotives are concentrated in only a few main cities. Regarding that, Baltic scientists and environment specialists nowadays are developing plans also for local air pollution decreasing, which can be carried out in particular cities or industrial areas, thereby allowing for improvements in air cleanliness and the ecological situation in concerned local area. A numerical estimation shows that applying the NYSMART technology, introduced in this paper, will make areas of active action of the high-volume diesels cleaner in the same amount as gained by photosynthesis of the urban green flora. In recent years, the developed technology of hydraulic piston compression allows producing numerous different vehicle fueling appliances for the CNG/bio-CNG fuel. The further development of this technology means the producing of various solutions, applicable at biogas/biomethane production sites, for CNG/bio-CNG compression, transportation and fast natural gas vehicles refueling in a cost effective and convenient way. The hydraulic piston compression and NYSMART have a potential in small and medium-scale technologies and therefore need to be developed further for applications with hydrogen. Production of biomethane and green hydrogen is delayed by the lack of state aid programmes in the Baltic States. Lithuania is on the way to change the situation in the coming years, with one of the first biomethane gas production plants due to be built near Panevėžys, in Šilagalys near the Via Baltica motorway. Summing up all aspects, the preconditions for the use of alternative fuels in the Baltic States are similar, allowing one to learn from other’s experience and to consider joint projects. © 2022. Journal of Ecological Engineering All Rights ReservedNational Research Programme VPP-EM-INFRA-2018/1-0003; Institute of Solid State Physics, University of Latvia has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART2

    PhyreStorm: A Web Server for Fast Structural Searches Against the PDB

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    AbstractThe identification of structurally similar proteins can provide a range of biological insights, and accordingly, the alignment of a query protein to a database of experimentally determined protein structures is a technique commonly used in the fields of structural and evolutionary biology. The PhyreStorm Web server has been designed to provide comprehensive, up-to-date and rapid structural comparisons against the Protein Data Bank (PDB) combined with a rich and intuitive user interface. It is intended that this facility will enable biologists inexpert in bioinformatics access to a powerful tool for exploring protein structure relationships beyond what can be achieved by sequence analysis alone. By partitioning the PDB into similar structures, PhyreStorm is able to quickly discard the majority of structures that cannot possibly align well to a query protein, reducing the number of alignments required by an order of magnitude. PhyreStorm is capable of finding 93±2% of all highly similar (TM-score>0.7) structures in the PDB for each query structure, usually in less than 60s. PhyreStorm is available at http://www.sbg.bio.ic.ac.uk/phyrestorm/

    Rumination Mediates the Relationship between Infant Temperament and Adolescent Depressive Symptoms

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    This study examined prospective associations between negative emotionality, rumination, and depressive symptoms in a community sample of 301 youths (158 females) followed longitudinally from birth to adolescence. Mothers reported on youths' negative emotionality (NE) at age 1, and youths self-reported rumination at age 13 and depressive symptoms at ages 13 and 15. Linear regression analyses indicated that greater NE in infancy was associated with more depressive symptoms at age 15, even after controlling for child gender and depressive symptoms at age 13. Moreover, analyses indicated that rumination significantly mediated the association between infancy NE and age 15 depressive symptoms in the full sample. When analyzed separately by gender, however, rumination mediated the relationship between NE and depressive symptoms for girls but not for boys. The results confirm and extend previous findings on the association between affective and cognitive vulnerability factors in predicting depressive symptoms and the gender difference in depression in adolescence, and suggest that clinical interventions designed to reduce negative emotionality may be useful supplements to traditional cognitive interventions for reducing cognitive vulnerability to depression

    Transport properties of an ionic magnetic colloid: experimental study of increasing the ionic strength

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    Abstract The phase separation of an ionic magnetic colloid in zero magnetic field by increasing the ionic strength is well known [Universite Paris VI, France, 1987; J. Colloid Interface Sci. 132 (1989) 1]. The present work deals with investigation of an ionic ferrofluid by increasing the ionic strength in the range of 0-0.14 mol/l, being safely below the threshold value at which the effect of phase separation occurs. By the optical grid setup [Fourth International conference PAMIR, France, 2000], the main transport properties of a ferrofluid, i.e. translational mass diffusion and thermal diffusion (Soret) coefficients, are measured. The obtained results show a strong dependence of mass diffusion coefficient and no dependence of the Soret coefficient upon increasing the ionic strength. It is possible to explain both these effects theoretically; nevertheless, there is the lack of an exact theoretical model due to its complexity.

    Studies on Water–Aluminum Scrap Reaction Kinetics in Two Steps and the Efficiency of Green Hydrogen Production

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    Baltic Research Programme project No. EEA-RESEARCH-92, EEA Grant No. EEZ/BPP/VIAA/2021/5. Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART2.This work aims to explain aluminum hydrolysis reaction kinetics based on a properly chosen theoretical model with machined aluminum waste chips as well as alkali solutions up to 1M as a promoter and to estimate the overall reaction profit. The purpose of this work is to assess the optimal alkali concentration in the production of small- and medium-scale green hydrogen. To obtain results with better accuracy, we worked with flat Al waste chips, because a flat surface is preferable to maximally increase the time for the created hydrogen bubbles to reach the critical gas pressure. Describing the reaction kinetics, a flat shape allows for the use of a planar one-dimensional shrinking core model instead of a much more complicated polydisperse spheric shrinking core model. We analyzed the surface chemical reaction and mass transfer rate steps to obtain the first-order rate constant for the surface reaction and the diffusion coefficient of the aqueous reactant in the byproduct layer, respectively. We noted that measurements of the diffusion coefficient in the byproduct layer performed and discussed in this paper are rare to find in publications at alkali concentrations below 1M. With our reactor, we achieved a H2 yield of 1145 mL per 1 g of Al with 1M NaOH, which is 92% of the theoretical maximum. In the estimation of profit, the authors’ novelty is in paying great attention to the loss in alkali and finding a crucial dependence on its price. Nevertheless, in terms of consumed and originated materials for sale, the conversion of aluminum waste material into green hydrogen with properly chosen reaction parameters has positive profit even when consuming an alkali of a chemical grade. © 2023 by the authors. --//-- Mezulis A., Richter C., Lesnicenoks P., Knoks A., Varnagiris S., Urbonavicius M., Milcius D., Kleperis J.; Studies on Water–Aluminum Scrap Reaction Kinetics in Two Steps and the Efficiency of Green Hydrogen Production; (2023) Energies, 16 (14), art. no. 5554; DOI: 10.3390/en16145554; https://www.scopus.com/inward/record.uri?eid=2-s2.0-85166176676&doi=10.3390%2fen16145554&partnerID=40&md5=ef6e4aed276993000c030ac11e1584e4. Published under the CC BY 4.0 licence.Baltic Research Programme project No. EEA-RESEARCH-92, EEA Grant No. EEZ/BPP/VIAA/2021/5. Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART2

    Changes in the relationship between self-reference and emotional valence as a function of dysphoria

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    The self-positivity bias is found to be an aspect of normal cognitive function. Changes in this bias are usually associated with changes in emotional states, such as dysphoria or depression. The aim of the present study was to clarify the role of emotional valence within self-referential processing. By asking non-dysphoric and dysphoric individuals to rate separately the emotional and self-referential content of a set of 240 words, it was possible to identify the differences in the relationship between self-reference and emotional valence, which are associated with dysphoria. The results support the existence of the self-positivity bias in non-dysphoric individuals. More interestingly, dysphoric individuals were able to accurately identify the emotional content of the word stimuli. They failed, however, to associate this emotional valence with self-reference. These findings are discussed in terms of attributional self-biases and their consequences for cognition
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