On isotactic polypropylene annealing: Difference in final properties of neat and β-nucleated polypropylene

The effect of isotactic polypropylene (iPP) molecular weight and thermal treatment on final crystalline structure and mechanical properties were investigated by X-ray scattering, differential scanning calorimetry, tensile testing, and scanning electron microscopy. Neat and β-nucleated isotactic polypropylene were subjected to annealing above melting temperature of β-phase but still below melting temperature of α-phase, which caused both improvement of α crystallites and β to α-recrystallization, in case of nucleated material. As a consequence, the final mechanical properties like tensile strength and stiffness improved significantly. The increase is much more pronounced in the case of β to α-transformed materials with lower molecular weight. This phenomenon can also be attributed to the partial preservation of the specific structure of the amorphous phase present in β-nucleated polypropylene, in addition to the perfection of the crystalline phase. The amorphous phase comprises many interconnecting chains passing through several lamellae whereby providing a long-range effect. © BME-PT.CZ.02.2.69/0.0/0.0/16_027/0008464, IGA/FT/2020/011, IGA/UTB/FT/2021/007; European Commission, ECEuropean UnionEuropean Commission [CZ.02.2.69/0.0/0.0/16_027/0008464, IGA/FT/2020/011, IGA/UTB/FT/2021/007

Components/factors of the Czech version of the Physical Self Perception Profile (PSPP-CZ) among high school students [Komponenty/faktory české verze dotazníku tělesného sebepojetí (PSPP-CZ) u středoškolských studentů]

BACKGROUND: The physical self has been widely investigated as a determinant of exercise behaviors as well as a contributor to mental health and well being (Fox, 1997). Self esteem has been generally accepted as an important mediator of exercise and self esteem (Fox, 2000; Sonstroem, 1997). Understanding self development processes has increased in importance as self esteem and self perception components have become increasingly valued in educational, clinical and community health programs (Ferreira & Fox, 2008). In order to examine the relationships between various levels of physical activities and self perception we need to use standardized instruments to measure physical self perception among Czech teenagers. OBJECTIVE: The purpose of this study was to analyse the structure of the translated PSPP-CZ questionnaire among the population of high school students by finding components of PSPP-CZ using principal component analysis. The Physical Self Perception Profile (PSPP) has never been used in the CZ population before. METHODS: Participants were high school students from five schools representing three kinds of high schools in the Czech Republic. Of these participants, 666 were boys and 403 were girls. The average age of the participants was 17.00 (± 1.34) in boys and 16.63 (± 1.39) in girls. Participants received a test battery containing a Czech version of PSPP (Fox, 1990). PSPP has four subscales: (a) sports competence – SPORT; (b) attractiveness of the figure – BODY; (c) physical strength and musculature – STRENGTH; and (d) physical conditioning and exercise – CONDITION (Fox, 1990). RESULTS: Data were analyzed using SPSS PC 11.0. Cronbach Alpha, representing the internal consistency measure consisted of: (a) sport subscale (males = .86, females = .86); (b) physical condition subscales (males = .82, females = .85); (c) attractiveness of figure subscales (males = .78, females = .88); and (d) strength subscale (males = .87, females = .85). Initially we have found that students from Czech high schools have a different structure of self perception then the original PSPP population from England (Fox, 1990). Our findings correspond with findings among Flemish adults (Van de Vliet et al., 2002; Ferreira & Fox, 2007) where components of sport and condition were also loaded into one factor. There are clear, subtle differences in the structure of physical self perception as related to cultural and language differences. Findings of internal reliability and content validity suggest that the three subscales questionnaire can be used in the Czech population as a valid and reliable instrument. CONCLUSIONS: In conclusion, we can recommend using the PSPP-CZ with three scales for use among young adults for the exploration of the role of physical self-perception as a determinant of physical activity/inactivity and a healthy lifestyle.[VÝCHODISKA: Tělesné sebepojetí bylo široce zkoumáno jako určující činitel pro cvičení stejně jako jeden z prvků majících vliv na duševní zdraví a blaho (Fox, 1997). Sebepojetí je všeobecně přijímáno jako významný prostředník mezi cvičením a sebeúctou (Fox, 2000; Sonstroem, 1997). Porozumění procesům seberozvoje nabylo na důležitosti, jelikož sebeúcta a sebepojetí jsou stále významnějšími komponenty vzdělávacích, klinických a komunitních programů péče o zdraví (Ferreira & Fox, 2008). Abychom mohli prozkoumat vztahy mezi různými úrovněmi tělesných aktivit a sebepojetí, musíme k měření tělesného sebepojetí mezi českými adolescenty využít standardizované nástroje. CÍLE: Účelem této studie bylo analyzovat strukturu přeloženého dotazníku PSPP-CZ mezi populací středoškolských studentů, a to hledáním komponentů PSPP-CZ za pomoci analýzy hlavních komponentů. Dotazník tělesného sebepojetí (Physical Self Perception Profi le, PSPP) na české populaci nikdy nebyl použit. METODIKA: Studie se zúčastnili středoškolští studenti z pěti škol reprezentujících tři typy škol v České republice, a to 666 chlapců a 403 dívek. Průměrný věk účastníků byl 17,00 (± 1,34) let u chlapců a 16,63 (± 1,39) let u dívek. Účastníci obdrželi soubor testů obsahující českou verzi PSPP (Fox, 1990). PSPP má čtyři subškály: a) sportovní dovednosti – SPORT; b) atraktivita postavy – TĚLO; c) fyzická síla a muskulatura – SÍLA; a d) fyzická příprava a cvičení – KONDICE (Fox, 1990). VÝSLEDKY: Údaje byly analyzovány za pomoci SPSS PC 11.0. Měřítko interní konzistence Cronbachova alfa zahrnovalo: a) subškálu sportu (muži = 0,86, ženy = 0,86); b) subškály tělesné kondice (muži = 0,82, ženy = 0,85); c) subškály atraktivity postavy (muži = 0,78, ženy = 0,88); a d) subškálu síly (muži = 0,87, ženy = 0,85). Nejprve jsme zjistili, že struktura sebepojetí u českých středoškoláků je odlišná od původní PSPP populace z Anglie (Fox, 1990). Naše zjištění korespondují s výsledky zjištěnými mezi vlámskými dospělými (Van de Vliet et al., 2002; Ferreira & Fox, 2007), kde komponenty sportu a kondice byly také součástí jednoho faktoru. Ve struktuře tělesného sebepojetí existují jasné, přesné rozdíly podmíněné kulturními a jazykovými odlišnostmi. Zjištění o interní reliabilitě a validitě obsahu naznačují, že dotazník se třemi subškálami lze u české populace použít jako účinný a spolehlivý nástroj. ZÁVĚRY: Doporučujeme použití PSPP-CZ se třemi škálami pro použití mezi mládeží ke zkoumání role tělesného sebepojetí jako určujícího činitele pohybové aktivity/neaktivity a zdravého životního stylu.

Increase of the effectiveness of school PE classes through sport preferences survey: Contextual prediction of demanded sport activities

BACKGROUND: An effort to promote participation in any type of PA is more effective when it is aimed at needs, interests and preferences of particular target group. Current evidence emphasizes the insufficiency of PA in all age groups. OBJECTIVE: The purpose of the study was to analyze and describe the structure of sport activity preferences of high school students and to contribute to prospective improvement of sports and physical activity programs. METHODS: Two standardized questionnaires were used – 1. sport preferences questionnaire, 2. international physical activity questionnaire (IPAQ). The research sample (N = 333) consisted of high school students from the Czech Republic. RESULTS: Our results confirm that the differences between girls and boys are not as great as they were few decades ago. There is a visible dynamic in the development of sport preferences structure. Despite this fact there is a spectrum of sports that are constantly preferred – soccer, volleyball, aerobics and swimming. Acquired results indicate that the range of PA amount in girls varies from 2,372 MET-min/week (15 year old girls) to 4,467 MET-min/week (17 year old girls), while acquired results in boys varies from 2,535 MET-min/week (16 year old boys) to 4,973 MET-min/week (17 year old boys). The results, if properly applied, could increase the total amount of PA in high school students and improve the effectiveness of school PE

National policy and mechanisms of development of local infrastructures for leisure-time physical activity - the Impala project

BACKGROUND: Inter-sectoral collaboration and social equity for all inhabitants of European Union in the sphere of approaching infrastructure for leisure-time physical activity (PA) were the main reasons for implementation and financing of international project IMPALA. The project was divided into three stages. AIM: The aim of presented part of IMPALA project is to assess national policy (legislation and regulation) of the development of local infrastructures for leisure-time PA. METHODS: According to the requirements established by project coordinator we carried out structured qualitative interviews with experts and policy makers on different decision-making levels. Further, the invited representatives of end users participated in focus group meeting. Also various available sources and documents were used for detailed analysis. RESULTS: Qualitative interviews provided information, which includes the issue of sports facilities in terms of national level and which documents deal with them. At the regional level whole sphere of infrastructures for leisure-time PA is organized by local and regional governments (municipalities). Participants in the focus group meeting shared with others their own positive and negative experiences with the management of infrastructures and finally made some concrete recommendations. The issue of mechanisms for infrastructure development devotes firstly to the relevant conceptual documents at national and regional level, and then describes specific examples of Olomouc and the Olomouc region in terms of planning, financing, construction and management of infrastructures for leisure-time PA. CONCLUSION: In this part of the project we found out that in the Czech Republic there is no specific national political strategy for the development of infrastructures for leisure-time PA. Development is done primarily at the local level. The biggest problem faced by end-operators is the lack of financial resources and outstanding legislation. On the other hand, participation of representatives of various stakeholder groups is appreciated in planning processes for the development of local infrastructures for leisure-time PA

Contemporary state and possibilities of improvement of local infrastructures for leisure-time physical activity from the aspect of national policy, planning, building, financing and management - the Impala project, part ii.

BACKGROUND: The second part of the IMPALA project was based on a wide discussion dealing with the problem of improving the local infrastructure for leisure time physical activity (LTPA) from practical and specific points of view that were represented by invited participants from all Czech regions. One of the results of the IMPALA project was the finding from some experts that physical environment mostly in adults contribute to an increase of physical activity. AIM: The main aim of this part of the IMPALA project is to present specifically discussed problems from the area of national policy, planning, building, financing and management of the infrastructure for LTPA. METHODS: A discussion was held during a national workshop that was organized in June 2010 at the Faculty of Physical Culture, Palacký University in Olomouc and had a strictly structured programme that was announced and prepared by the main project coordinator. A discussion took place firstly in small groups according to each section (planning, building, financing, and management) toward the assessment of a contemporary state and later on proposals whether some improvements exist. RESULTS: The biggest problem connected with planning is the non-existence of external as well as an internal evaluation of a planning process. In the building area the main problem is the accessibility of infrastructures in small villages; social-spatial aspects are not taken into account and building is also influenced by land ownership. Financing of local infrastructures for LTPA is very diverse, from public sources to private and also in different business models. Existing financial models are secured by law contracts and taken into account by operating costs. Focusing on management of infrastructures differs according to the owner, to financial sources, and to the type of infrastructure. Overemphasizing of top sport means higher allocation of finance mostly into sport infrastructures that are not or cannot be used by the wide public. CONCLUSION: The state policy in the sphere of an infrastructure for LTPA should be established regardless of the policy situation and should be supported in legislation. On the national level, there should exist connectivity among ministries, on the local level there should exist close cooperation among relevant sectors. Questions of policy should deal with the possibility for improving the infrastructure for LTPA for a wide public with regard to age, social, ethic and other population groups

Compensation for Adolescents’ School Mental Load by Physical Activity on Weekend Days

Introduction and objective: Increasing mental load and inadequate stress management significantly affect the efficiency, success and safety of the educational/working process in adolescents. The objective of this study is to determine the extent that adolescents compensate for their school mental load by physical activity (PA) on weekend days and, thus, to contribute to the objective measurement of mental load in natural working conditions. Methods: A cross-sectional study was conducted between September 2013 and April 2014. A set of different methods was employed—self-administered questionnaire (IPAQ-long questionnaire), objective measurements—pedometers, and accelerometers (ActiTrainers). They was distributed to 548 students from 17 high schools. Participants’ mental load was assessed based on the difference between PA intensity and/or physical inactivity and heart rate range. Results: The participants with the highest mental load during school lessons do not compensate for this load by PA on weekend days. Conclusions: Adolescents need to be encouraged to be aware of their subjective mental load and to intentionally compensate for this load by PA on weekend days. It is necessary to support the process of adopting habits by sufficient physical literacy of students, as well as teachers, and by changes in the school program

The Differences in Physical Activity Preferences and Practices among High versus Low Active Adolescents in Secondary Schools

This study aimed to (a) identify the differences in the preferred, practiced, and organized physical activity (PA) between high and low physically active Czech and Polish boys and girls and to (b) identify which types of PA are likely to be recommended by low active boys and girls. The research was carried out between 2010 and 2019 in the Czech Republic and Poland and included 6619 participants aged 15 to 19 years. The preferences and practices of the different types of PA and participation in organized PA were identified using a PA preference questionnaire and weekly PA was identified using the International Physical Activity Questionnaire-long form. Czech and Polish boys and girls who were low active preferred less physically demanding and more health-oriented PA compared with high active individuals. Power exercises and participation in organized PA are the most significant predictors of achieving at least 3 × 20 min of vigorous PA per week among low active individuals in both countries. Monitoring the trends in the preferred and practiced types of PA among boys and girls is crucial for the effective promotion of PA to low active boys and girls and positive changes in physical education and school health policy

Mixed-Mating Model of Reproduction Revealed in European <i>Phytophthora cactorum</i> by ddRADseq and Effector Gene Sequence Data

A population study of Phytophthora cactorum was performed using ddRADseq sequence variation analysis completed by the analysis of effector genes—RXLR6, RXLR7 and SCR113. The population structure was described by F-statistics, heterozygosity, nucleotide diversity, number of private alleles, number of polymorphic sites, kinship coefficient and structure analysis. The population of P. cactorum in Europe seems to be structured into host-associated groups. The isolates from woody hosts are structured into four groups described previously, while isolates from strawberry form another group. The groups are diverse in effector gene composition and the frequency of outbreeding. When populations from strawberry were analysed, both asexual reproduction and occasional outbreeding confirmed by gene flow among distinct populations were detected. Therefore, distinct P. cactorum populations differ in the level of heterozygosity. The data support the theory of the mixed-mating model for P. cactorum, comprising frequent asexual behaviour and inbreeding alternating with occasional outbreeding. Because P. cactorum is not indigenous to Europe, such variability is probably caused by multiple introductions of different lineages from the area of its original distribution, and the different histories of sexual recombination and host adaptation of particular populations

Objectification of the school-related transport monitoring of the adolescents

BACKGROUND: School and school-related physical activity (PA) are important for the total PA of children and youth. The total amount of PA is higher within school days compare to weekends. Children and youth, who use active transportation (to/from the school), confirm the higher PA per week compared to those without active transportation (using car, train, bus). There is a lack of available data in the Czech Republic about active transportation of children and adolescents. AIM: The main aim of the study is the objectification of the school-related transport monitoring of the adolescents. One of the additional outcomes is to enrich this relatively new scientific area in the Czech Republic. METHODS: There was one high school chosen for this project - Gymnázium Nový Jičín. Data were collected by using ActiGraph GT1M, pedometer YAMAX SW-700, NQLS questionnaire and internet system INDARES. RESULTS: By using the newly developer map module "tracker", within the system INDARES, we could compare the participants which active transport (AT) was lower than 1000 m, with participants with the AT values higher than 1000 m. We found out significant di&#xFB00;erences between school days and weekends in the intensity of 1 to 3 MET. The statistical significance was supported by the coefficient e&#xFB00;ect size (d = 0.83). The participants recording AT values lower than 1000 m showing significantly higher level of PA in school days then during weekends (p = .003; F = 26.149; &omega;2 = 0.456). Similar results were found in participants recording AT values higher than 1000 m; the di&#xFB00;erences between school days and weekends are highly significant (p = .0004; F = 26.149; &omega; 2 = 0.456). CONCLUSIONS: We have contributed to the objectification of the school-related transport monitoring of the adolescents by the creation of the map module within the INDARES system. The usage of a triangulation approach (objective methods - subjective methods - system INDARES) into the PA monitoring in the context of AT pretends flexible and available research tool, is helpful in describing modern trends and elements of PA monitoring with the focus on environment. The level of AT to/from the school is the important role in the total PA level in children and youth

The competition between self-seeding and specific nucleation in crystallization of long-chain branched polypropylene

The main purpose of this work is to present the effect of long-chain branching and specific α-nucleation on the optical properties, crystallization and supermolecular structure of polypropylene (PP). Commercially available α-nucleating/ clarifying agent 1,3;2,4-bis(3,4-dimethylbenzylidene)sorbitol (Millad 3988) was mixed into linear PP and long-chain branched PP (LCB-PP) in the concentration of 0.2 wt%. For the study of polymorphic composition, crystallinity, and crystallization process under isothermal conditions in the temperature range of 130–150 °C, differential scanning calorimetry and wide-angle X-ray scattering were used. Although the used nucleating/clarifying agent appears to have a slight effect on the optical properties of long-chain branched polypropylene, it does not appear to affect the crystallization kinetics significantly. LCB-PP exhibited self-nucleation, favored over nucleation by a specific nucleating agent.Tomas Bata University in Zlin, TBU, (CZ.02.2.69/0.0/0.0/19_073/0016941)project OP VVV Junior Grants TBU in Zlin [CZ.02.2.69/0.0/0.0/19_073/0016941