This study investigated the impact of Hofstede cultural dimensions on sustainable competitive advantage with the mediating role of entrepreneurial innovativeness among Malays, Malaysian Chinese, and Malaysian Indian entrepreneurs in the retail industry. This study involved a quantitative approach with standardized questionnaires distributed among target respondents through non-probability sampling techniques, including snowball sampling, quota sampling, and convenience sampling. The data were collected in a cross-sectional setting from Malaysian retail ethnic entrepreneurs. AMOS-SEM and SPSS were used to analyze the data. The findings of this study revealed a positive and significant influence of indulgence, long-term orientation, masculinity, and low power distance on sustainable competitive advantage among Chinese, Malay, and Indian entrepreneurs. Furthermore, the direct effect of entrepreneurial innovativeness was also positive and significant in terms of sustainable competitive advantage among Chinese, Malay, and Indian entrepreneurs. Finally, the indirect effects of collectivism, indulgence, low uncertainty avoidance, low power distance, masculinity, and long-term orientation on sustainable competitive advantage through mediator entrepreneurial innovativeness were positive and significant among Malaysian Chinese. However, in Malay (indulgence) and India (collectivism, low uncertainty avoidance, and low power distance), these were not significant. Our results suggest that academics and businesses should consider how cultural norms of masculinity, long-term orientation, and uncertainty avoidance impact sustainable competitive advantage activities. Rewards encouraging sustainable competitive advantage in one subculture may not promote it in another. Subcultural norms influence entrepreneurs' decisions, expectations, and incentives in a culturally diverse community.

• Klíčová slova
• Entrepreneurial innovativeness, Hofstede cultural values, Malaysian ethnic entrepreneurs, Sustainable competitive advantage,
• MeSH
• dospělí MeSH
• etnicita psychologie   MeSH
• kompetitivní chování MeSH
• kreativita MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• mužskost MeSH
• podnikání * MeSH
• průřezové studie MeSH
• průzkumy a dotazníky MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Malajsie etnologie   MeSH

Rapid environmental changes across Europe include warmer and increasingly variable temperatures, changes in soil nutrient availability, and pollinator decline. These abiotic and biotic changes can affect natural plant populations and force them to optimize resource use against competitors. To date, the evolution of competitive ability in the context of changes in nutrient availability remains understudied. In this study, we investigated whether the common calcareous grassland herb Leontodon hispidus recently evolved its competitive ability and response to nutrient availability. We compared ancestors sampled in 1995 and descendants sampled in 2018 and applied a competition treatment in combination with weekly nutrient treatments (no fertilizer, nitrogen, phosphorus, and both). We found evidence for evolution of increased competitive ability, with descendants producing more vegetative biomass than ancestors when grown under competition. Furthermore, supplementing nutrients (especially N) reduced differences in competitive ability between ancestors and descendants, suggesting that nutrients are a limiting factor in interspecific competition, which could be linked to the decreasing nitrogen emissions into the atmosphere since the 1990s. Our study demonstrates rapid contemporary evolution of competitive ability, but also the complexity of the underlying processes of contemporary evolution, and sheds light on the importance of understudied potential selection agents such as nutrient availability.

• Klíčová slova
• Competition, Fertilization experiment, Global change, Rapid evolution, Resurrection approach,
• MeSH
• biologická evoluce * MeSH
• biomasa MeSH
• dusík metabolismus   MeSH
• fosfor MeSH
• pastviny * MeSH
• půda chemie   MeSH
• živiny MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• dusík MeSH
• fosfor MeSH
• půda MeSH

In freshwater systems, cyanobacteria are strong competitors under enhanced temperature and eutrophic conditions. Understanding their adaptive and evolutionary potential to multiple environmental states allows us to accurately predict their response to future conditions. To better understand if the combined impacts of temperature and nutrient limitation could suppress the cyanobacterial blooms, a single strain of Microcystis aeruginosa was inoculated into natural phytoplankton communities with different nutrient conditions: oligotrophic, eutrophic and eutrophic with the addition of bentophos. We found that the use of the bentophos treatment causes significant differences in prokaryotic and eukaryotic communities. This resulted in reduced biodiversity among the eukaryotes and a decline in cyanobacterial abundance suggesting phosphorus limitation had a strong impact on the community structure. The low temperature during the experiment lead to the disappearance of M. aeruginosa in all treatments and gave other phytoplankton groups a competitive advantage leading to the dominance of the eukaryotic families that have diverse morphologies and nutritional modes. These results show cyanobacteria have a reduced competitive advantage under certain temperature and nutrient limiting conditions and therefore, controlling phosphorus concentrations could be a possible mitigation strategy for managing harmful cyanobacterial blooms in a future warmer climate.

• MeSH
• eutrofizace MeSH
• fosfor MeSH
• fytoplankton MeSH
• jezera chemie   MeSH
• lidé MeSH
• Microcystis * MeSH
• sinice * MeSH
• teplota MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• fosfor MeSH

Invasions by alien plants provide a unique opportunity to examine competitive interactions among plants. While resource competition has long been regarded as a major mechanism responsible for successful invasions, given a well-known capacity for many invaders to become dominant and reduce plant diversity in the invaded communities, few studies have measured resource competition directly or have assessed its importance relative to that of other mechanisms, at different stages of an invasion process. Here, we review evidence comparing the competitive ability of invasive species vs. that of co-occurring native plants, along a range of environmental gradients, showing that many invasive species have a superior competitive ability over native species, although invasive congeners are not necessarily competitively superior over native congeners, nor are alien dominants are better competitors than native dominants. We discuss how the outcomes of competition depend on a number of factors, such as the heterogeneous distribution of resources, the stage of the invasion process, as well as phenotypic plasticity and evolutionary adaptation, which may result in increased or decreased competitive ability in both invasive and native species. Competitive advantages of invasive species over natives are often transient and only important at the early stages of an invasion process. It remains unclear how important resource competition is relative to other mechanisms (competition avoidance via phenological differences, niche differentiation in space associated with phylogenetic distance, recruitment and dispersal limitation, indirect competition, and allelopathy). Finally, we identify the conceptual and methodological issues characterizing competition studies in plant invasions, and we discuss future research needs, including examination of resource competition dynamics and the impact of global environmental change on competitive interactions between invasive and native species.

• Klíčová slova
• apparent competition, competitive ability, dominance, evolutionary adaptation, phenology, phenotypic plasticity, phylogenetic relatedness, resource gradient,
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Purpose: Simulated competition as a training tool has a relevant role in enhancement of exercise intensity, motivation and physical enjoyment. Including a competitive component into the agility training could represent another way to improve agility performance significantly more. The aim of this study was to assess the effect of agility training performed in the form of competitive exercising on agility performance. Methods: Twenty-two athletes were randomly assigned to an experimental or a control group. Both groups completed the same eight-week agility training, but only the experimental group performed exercises in the form of head-to-head competition. Prior to and after the training, agility time in the Agility Dual test (performed in pairs in the form of head-to-head competition) and Agility Single test (performed individually) was measured. In addition, simple and two-choice reaction time and speed of step initiation were also assessed. Results: A significant group × time interaction effect was observed for agility time in the Agility Dual test only (p = .002). This effect occurred in favor of experimental group (18%, p < .01). No further significant interactions were detected. Conclusions: Competitive agility training led to significant improvement of agility time under competitive conditions only. This training does not contribute to more pronounced improvements of other reaction and speed abilities.

• Klíčová slova
• Agility time, head-to-head exercising, motor component, perceptual-cognitive component,
• MeSH
• cvičení fyziologie   MeSH
• dospělí MeSH
• kompetitivní chování fyziologie   MeSH
• lidé MeSH
• mladý dospělý MeSH
• sportovní výkon fyziologie   MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• randomizované kontrolované studie MeSH

Phenotypic plasticity, within and across generations (transgenerational plasticity), allows organisms and their progeny to adapt to the environment without modification of the underlying DNA. Recent findings suggest that epigenetic modifications are important mediators of such plasticity. However, empirical studies have, so far, mainly focused on plasticity in response to abiotic factors, overlooking the response to competition. We tested for within-generation and transgenerational phenotypic plasticity triggered by plant-plant competition intensity, and we tested whether it was mediated via DNA methylation, using the perennial, apomictic herb Taraxacum brevicorniculatum in four coordinated experiments. We then tested the consequences of transgenerational plasticity affecting competitive interactions of the offspring and ecosystem processes, such as decomposition. We found that, by promoting differences in DNA methylation, offspring of plants under stronger competition developed faster and presented more resource-conservative phenotypes. Further, these adjustments associated with less degradable leaves, which have the potential to reduce nutrient turnover and might, in turn, favour plants with more conservative traits. Greater parental competition enhanced competitive abilities of the offspring, by triggering adaptive phenotypic plasticity, and decreased offspring leaf decomposability. Our results suggest that competition-induced transgenerational effects could promote rapid adaptations and species coexistence and feed back on biodiversity assembly and nutrient cycling.

• Klíčová slova
• DNA methylation, adaptation, decomposition, functional traits, intraspecific phenotypic variability, parental effects, plant competition, transgenerational epigenetic inheritance,
• MeSH
• ekosystém * MeSH
• fenotyp MeSH
• fyziologická adaptace * MeSH
• listy rostlin MeSH
• metylace DNA MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

OBJECTIVE: Cancer stem-like cells (CSLCs) are considered a root of tumorigenicity and resistance. However, their identification remains challenging. The use of the side population (SP) assay as a credible marker of CSLCs remains controversial. The SP assay relies on the elevated activity of ABC transporters that, in turn, can be modulated by hypericin (HYP), a photosensitizer and bioactive compound of St. John's Wort (Hypericum perforatum), a popular over-the-counter antidepressant. Here we aimed to comprehensively characterize the SP phenotype of cancer cells and to determine the impact of HYP on these cells. METHODS: Flow cytometry and sorting-based assays were employed, including CD24-, CD44-, CD133-, and ALDH-positivity, clonogenicity, 3D-forming ability, ABC transporter expression and activity, and intracellular accumulation of HYP/Hoechst 33342. The tumorigenic ability of SP, nonSP, and HYP-treated cells was verified by xenotransplantation into immunodeficient mice. RESULTS: The SP phenotype was associated with elevated expression of several investigated transporters and more intensive growth in non-adherent conditions but not with higher clonogenicity, tumorigenicity or ALDH-positivity. Despite stimulated BCRP level and MRP1 activity, HYP reversibly decreased the SP proportion, presumably via competitive inhibition of BCRP. HYP-selected SP cells acquired additional traits of resistance and extensively eliminated HYP. CONCLUSIONS: Our results suggest that SP is not an unequivocal CSLC-marker. However, SP could play an important role in modulating HYP-treatment and serve as a negative predictive tool for HYP-based therapies. Moreover, the use of supplements containing HYP by cancer patients should be carefully considered, due to its proposed effect on drug efflux and complex impact on tumor cells, which have not yet been sufficiently characterized.

• Klíčová slova
• ABC transporters, Cancer stem-like cells, Drug resistance, Hypericin, Side population, St. John’s wort,
• MeSH
• ABC transportér z rodiny G, člen 2 metabolismus   MeSH
• aldehyddehydrogenasa metabolismus   MeSH
• analýza přežití MeSH
• anthraceny MeSH
• buněčné klony MeSH
• buněčné sféroidy účinky léků   metabolismus   patologie   MeSH
• fenotyp MeSH
• karcinogeneze účinky léků   metabolismus   patologie   MeSH
• lidé MeSH
• myši SCID MeSH
• nádorové biomarkery metabolismus   MeSH
• nádorové buněčné linie MeSH
• nádorové kmenové buňky účinky léků   metabolismus   patologie   MeSH
• nádorové proteiny metabolismus   MeSH
• nádory metabolismus   patologie   MeSH
• P-glykoprotein metabolismus   MeSH
• perylen analogy a deriváty   farmakologie   MeSH
• substrátová specifita účinky léků   MeSH
• vedlejší populace buněk účinky léků   patologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• ABC transportér z rodiny G, člen 2 MeSH
• ABCG2 protein, human MeSH Prohlížeč
• aldehyddehydrogenasa MeSH
• anthraceny MeSH
• hypericin MeSH Prohlížeč
• nádorové biomarkery MeSH
• nádorové proteiny MeSH
• P-glykoprotein MeSH
• perylen MeSH

Coexistence of species with similar requirements is allowed, among others, through trade-offs between competitive ability and other ecological traits. Although interspecific competition is based on two mechanisms, exploitation of resources and physical interference, trade-off studies largely consider only species' ability to exploit resources. Using a mesocosm experiment, we examined the trade-off between interference competition ability and susceptibility to predation in larvae of two newt species, Ichthyosaura alpestris and Lissotriton vulgaris. In the presence of heterospecifics, L. vulgaris larvae slowed somatic growth and developmental rates, and experienced a higher frequency of injuries than in conspecific environments which suggests asymmetrical interspecific interference. During short-term predation trials, L. vulgaris larvae suffered higher mortality than I. alpestris. Larvae of the smaller species, L. vulgaris, had both lower interference and antipredator performance than the larger I. alpestris, which suggests a lack of trade-off between interference competition ability and predator susceptibility. We conclude that interference competition may produce a positive rather than negative relationship with predation susceptibility, which may contribute to the elimination of subordinate species from common habitats.

• Klíčová slova
• amphibians, interspecific aggression, predator‐prey interaction, somatic growth, species coexistence,
• Publikační typ
• časopisecké články MeSH

UNLABELLED: Due to the limited array of the currently available copper chelators, research of such compounds continues to be of clinical interest. Notably, o-dihydroxycoumarins have been previously shown to be potent iron chelators under neutral conditions. Within this study, the interaction of a series of natural coumarins and their synthetic analogs with copper has been evaluated in order to obtain structure-activity relationships under different pathophysiological pH conditions. Both competitive and non-competitive methods have been employed. Analysis of cupric ion reduction has also been performed. Under mildly competitive conditions, cupric chelation was observed for o-dihydroxycoumarins, and partially for o-diacetoxycoumarin. Non-competitive studies showed that cuprous ions are not chelated at all and that the stoichiometries of the most active 6,7- and 7,8-dihydroxycoumarins to cupric ions ranged from 1:1 to 2:1 depending on pH and concentration. Interestingly, under highly competitive conditions, coumarins were not capable of chelating cupric ions, either. Reduction experiments have shown that 13 out of the 15 coumarins included in this study reduced cupric ions. However, significant differences depending on their structures were apparent in their potencies. O-dihydroxycoumarins were the most potent ones again. CONCLUSION: O-dihydroxycoumarins are moderately active cupric ion chelators with potent copper reducing properties.

• Klíčová slova
• Catecholic, Chelation, Copper, Coumarin, Reduction,
• MeSH
• chelátory chemie   MeSH
• fluorescenční barviva chemie   MeSH
• fluorescenční spektrometrie metody   MeSH
• koncentrace vodíkových iontů MeSH
• kumariny chemie   MeSH
• měď analýza   MeSH
• oxidace-redukce MeSH
• stereoizomerie MeSH
• vztahy mezi strukturou a aktivitou MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• chelátory MeSH
• cuprous ion MeSH Prohlížeč
• fluorescenční barviva MeSH
• kumariny MeSH
• měď MeSH

The capability of speech understanding can be tested in the form of sentences. This report describes the origin of a new test in the Czech language to evaluate the sentence intelligibility with the presence of the competitive disturb noise. The results of the test depend on the test project, sentence material, competitive signal, test evaluation, and hearing conditions. Pilot results were obtained from 3 different noises (Speech noise, Babble noise, Cocktail party noise) at 16 people with a normal hearing ability. The Speech noise, which is recommended by a technical standard, mask sentences very poorly. On the other hand, the Babble noise and the Cocktail party noise, which are used to mask sentences in different languages, mask at lower intensities.

• MeSH
• audiometrie MeSH
• dospělí MeSH
• hluk * MeSH
• lidé středního věku MeSH
• lidé MeSH
• testy sluchového rozlišování * MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH