966 research outputs found

    Interval total colorings of graphs

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    A total coloring of a graph GG is a coloring of its vertices and edges such that no adjacent vertices, edges, and no incident vertices and edges obtain the same color. An \emph{interval total tt-coloring} of a graph GG is a total coloring of GG with colors 1,2,.Ë™.,t1,2,\...,t such that at least one vertex or edge of GG is colored by ii, i=1,2,.Ë™.,ti=1,2,\...,t, and the edges incident to each vertex vv together with vv are colored by dG(v)+1d_{G}(v)+1 consecutive colors, where dG(v)d_{G}(v) is the degree of the vertex vv in GG. In this paper we investigate some properties of interval total colorings. We also determine exact values of the least and the greatest possible number of colors in such colorings for some classes of graphs.Comment: 23 pages, 1 figur

    Fundamental Movement Skills of Preschool Children in Northwest England

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    Summary. - This cross-sectional study examined fundamental movement skill competency among deprived preschool children in Northwest England and explored sex differences. A total of 168 preschool children (age 3-5 years) were included in the study. Twelve skills were assessed using the Children’s Activity and Movement in Preschool Motor Skills Protocol and video analysis. Sex differences were explored using independent t-tests, Mann-Whitney U-test and Chi Square analysis at the subtest, skill and component levels, respectively. Overall competence was found to be low amongst both sexes, although it was higher for locomotor skills than for object-control skills. Similar patterns were observed at the component level. Boys had significantly better object-control skills than girls, with greater competence observed for the kick and overarm throw, whilst girls were more competent at the run, hop and gallop. The findings of low competency suggest that developmentally-appropriate interventions should be implemented in preschool settings to promote movement skills, with targeted activities for boys and girls

    Fundamental Movement Skills in relation to weekday and weekend physical activity in preschool children

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    OBJECTIVES: To examine associations between fundamental movement skills and weekday and weekend physical activity among preschool children living in deprived communities. DESIGN: Cross-sectional observation study. METHODS: Six locomotor skills and 6 object-control skills were video-assessed using The Children's Activity and Movement in Preschool Study Motor Skills Protocol. Physical activity was measured via hip-mounted accelerometry. A total of 99 children (53% boys) aged 3-5 years (M 4.6, SD 0.5) completed all assessments. Multilevel mixed regression models were used to examine associations between fundamental movement skills and physical activity. Models were adjusted for clustering, age, sex, standardised body mass index and accelerometer wear time. RESULTS: Boys were more active than girls and had higher object-control skill competency. Total skill score was positively associated with weekend moderate-to-vigorous physical activity (p=0.034) but not weekday physical activity categories (p>0.05). When subdomains of skills were examined, object-control skills was positively associated with light physical activity on weekdays (p=0.008) and with light (p=0.033), moderate-to-vigorous (p=0.028) and light- and moderate-to-vigorous (p=0.008) physical activity at weekends. Locomotor skill competency was positively associated with moderate-to-vigorous physical activity on weekdays (p=0.016) and light physical activity during the weekend (p=0.035). CONCLUSIONS: The findings suggest that developing competence in both locomotor and object-control skills may be an important element in promoting an active lifestyle in young children during weekdays and at weekends

    Handling method alters the hedonic value of reward in laboratory mice

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    Mice are the most widely used model species for drug discovery and scientific research. Consequently, it is important to refine laboratory procedures and practices to ensure high standards of welfare and scientific data quality. Recent studies have identified that the standard practice of handling laboratory mice by their tails increases behaviours indicative of anxiety, which can be overcome by handling mice using a tunnel. However, despite clear negative effects on mice’s behaviour, tunnel handling has yet to be widely implemented. In this study, we provide the first evidence that tail handling also reduces mice’s responses to reward. Anhedonia is a core symptom of clinical depression, and is measured in rodents by assessing how they consume a sucrose solution: depressed mice consume less sucrose and the size of their licking bouts when drinking (their ‘lick cluster sizes’) also tend to be smaller. We found that tail handled mice showed more anhedonic responses in both measures compared to tunnel handled mice, indicative of a decreased responsiveness to reward and potentially a more depressive-like state. Our findings have significant implications for the welfare of laboratory mice as well as the design and interpretation of scientific studies, particularly those investigating or involving reward

    The antimicrobial polymer PHMB enters cells and selectively condenses bacterial chromosomes

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    To combat infection and antimicrobial resistance, it is helpful to elucidate drug mechanism(s) of action. Here we examined how the widely used antimicrobial polyhexamethylene biguanide (PHMB) kills bacteria selectively over host cells. Contrary to the accepted model of microbial membrane disruption by PHMB, we observed cell entry into a range of bacterial species, and treated bacteria displayed cell division arrest and chromosome condensation, suggesting DNA binding as an alternative antimicrobial mechanism. A DNA-level mechanism was confirmed by observations that PHMB formed nanoparticles when mixed with isolated bacterial chromosomal DNA and its effects on growth were suppressed by pairwise combination with the DNA binding ligand Hoechst 33258. PHMB also entered mammalian cells, but was trapped within endosomes and excluded from nuclei. Therefore, PHMB displays differential access to bacterial and mammalian cellular DNA and selectively binds and condenses bacterial chromosomes. Because acquired resistance to PHMB has not been reported, selective chromosome condensation provides an unanticipated paradigm for antimicrobial action that may not succumb to resistance

    Smoking status and common carotid artery intima-medial thickness among middle-aged men and women based on ultrasound measurement: a cohort study

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    BACKGROUND: Cigarette smoking is an established causal factor for atherosclerosis. However, the smoking effect on different echogenic components of carotid arterial wall measured by ultrasound is not well elucidated. METHODS: Middle-aged men and women who had IMT measurement ≥ 0.7 mm at baseline and follow-up were included (N = 413, age 40–60 years at baseline in 1995). Intima-media thickness of common carotid artery (CCA-IMT) and its components (echogenic and echolucent layers) were measured at baseline and in the follow-up examination 3 years later. IMT and its components were compared across current, former and never smokers. Individual growth models were used to examine how smoking status was related to the baseline and progression of overall IMT and IMT components. RESULTS: For both men and women, current smoking was associated with thicker echogenic layer than never smokers; former smokers exhibited thinner echogenic layer than current smokers after adjustment for cigarette pack-years. Among women, current smoking was also associated with a thinned echolucent layer that resulted in a non-significant overall association of current smoking with IMT for women. CONCLUSION: Cigarette smoking is associated with carotid artery morphological changes and the association is sex-dependent. The atherogenic effect of smoking appears to be partly reversible among former smokers. IMT measurement alone may not be adequate to detect carotid atherosclerosis associated with cigarette smoking among middle-age women

    Long term time variability of cosmic rays and possible relevance to the development of life on Earth

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    An analysis is made of the manner in which the cosmic ray intensity at Earth has varied over its existence and its possible relevance to both the origin and the evolution of life. Much of the analysis relates to the 'high energy' cosmic rays (E>1014eV;=0.1PeVE>10^{14}eV;=0.1PeV) and their variability due to the changing proximity of the solar system to supernova remnants which are generally believed to be responsible for most cosmic rays up to PeV energies. It is pointed out that, on a statistical basis, there will have been considerable variations in the likely 100 My between the Earth's biosphere reaching reasonable stability and the onset of very elementary life. Interestingly, there is the increasingly strong possibility that PeV cosmic rays are responsible for the initiation of terrestrial lightning strokes and the possibility arises of considerable increases in the frequency of lightnings and thereby the formation of some of the complex molecules which are the 'building blocks of life'. Attention is also given to the well known generation of the oxides of nitrogen by lightning strokes which are poisonous to animal life but helpful to plant growth; here, too, the violent swings of cosmic ray intensities may have had relevance to evolutionary changes. A particular variant of the cosmic ray acceleration model, put forward by us, predicts an increase in lightning rate in the past and this has been sought in Korean historical records. Finally, the time dependence of the overall cosmic ray intensity, which manifests itself mainly at sub-10 GeV energies, has been examined. The relevance of cosmic rays to the 'global electrical circuit' points to the importance of this concept.Comment: 18 pages, 5 figures, accepted by 'Surveys in Geophysics

    The Leader programme 2007-2013: Enabling or disabling social innovation and neo-endogenous development? Insights from Austria and Ireland

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    Since the beginning of the 1990s, the Leader programme has been hailed as the instrument of rural policy that most explicitly takes account of the territorial dimension. This culminated in the mainstreaming of its underlying concept into the Rural Development Programmes of the current period (2007–2013), with the aim of having more effective policy implementation that considers the diversified needs of rural regions. Starting from analysis of the application and delivery of Leader under the present Rural Development Programme in two EU countries, Austria and Ireland, this paper presents an assessment of the effects of this programme change. In addition, it includes the EU-wide discussion on the (limited) effectiveness of the current implementation of Leader and the search for a reorientation towards local development activities in the EU’s reform proposals. The paper frames the analysis around the notion of social innovation, a concept of central importance to the aims of Leader. It is argued that the implementation of Leader in this period falls far behind its potential to beneficially impact rural regions; hence it should be an object of critical debate in the reform of the Common Agricultural Policy and rural development measures, as well as coherence analyses with other policies, beyond 2013

    Addressing gaps in care of people with conditions affecting sex development and maturation

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    Differences of sex development are conditions with discrepancies between chromosomal, gonadal and phenotypic sex. In congenital hypogonadotropic hypogonadism, a lack of gonadotropin activity results primarily in the absence of pubertal development with prenatal sex development being (almost) unaffected in most patients. To expedite progress in the care of people affected by differences of sex development and congenital hypogonadotropic hypogonadism, the European Union has funded a number of scientific networks. Two Actions of the Cooperation of Science and Technology (COST) programmes - DSDnet (BM1303) and GnRH Network (BM1105) - provided the framework for ground-breaking research and allowed the development of position papers on diagnostic procedures and special laboratory analyses as well as clinical management. Both Actions developed educational programmes to increase expertise and promote interest in this area of science and medicine. In this Perspective article, we discuss the success of the COST Actions DSDnet and GnRH Network and the European Reference Network for Rare Endocrine Conditions (Endo-ERN), and provide recommendations for future research
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