Showing papers by "University of Jyväskylä published in 2009"

EPS09: A New Generation of NLO and LO Nuclear Parton Distribution Functions

Abstract: We present a next-to-leading order (NLO) global DGLAP analysis of nuclear parton distribution functions (nPDFs) and their uncertainties. Carrying out an NLO nPDF analysis for the first time with three different types of experimental input — deep inelastic l+A scattering, Drell-Yan dilepton production in p+A collisions, and inclusive pion production in d+Au and p+p collisions at RHIC — we find that these data can well be described in a conventional collinear factorization framework. Although the pion production has not been traditionally included in the global analyses, we find that the shape of the nuclear modification factor RdAu of the pion pT-spectrum at midrapidity retains sensitivity to the gluon distributions, providing evidence for shadowing and EMC-effect in the nuclear gluons. We use the Hessian method to quantify the nPDF uncertainties which originate from the uncertainties in the data. In this method the sensitivity of χ2 to the variations of the fitting parameters is mapped out to orthogonal error sets which provide a user-friendly way to calculate how the nPDF uncertainties propagate to any factorizable nuclear cross-section. The obtained NLO and LO nPDFs and the corresponding error sets are collected in our new release called family EPS09. These results should find applications in precision analyses of the signatures and properties of QCD matter at the LHC and RHIC.

White phosphorus is air-stable within a self-assembled tetrahedral capsule.

Abstract: The air-sensitive nature of white phosphorus underlies its destructive effect as a munition: Tetrahedral P4 molecules readily react with atmospheric dioxygen, leading this form of the element to spontaneously combust upon exposure to air. Here, we show that hydrophobic P4 molecules are rendered air-stable and water-soluble within the hydrophobic hollows of self-assembled tetrahedral container molecules, which form in water from simple organic subcomponents and iron(II) ions. This stabilization is not achieved through hermetic exclusion of O2 but rather by constriction of individual P4 molecules; the addition of oxygen atoms to P4 would result in the formation of oxidized species too large for their containers. The phosphorus can be released in controlled fashion without disrupting the cage by adding the competing guest benzene.

The Construct Validity of the Utrecht Work Engagement Scale: Multisample and Longitudinal Evidence

Abstract: This study investigated the factor structure and factorial group and time invariance of the 17-item and 9-item versions of the Utrecht Work Engagement Scale (UWES; Schaufeli et al. (2002b) Journal of Happiness Studies 3:71–92). Furthermore, the study explored the rank-order stability of work engagement. The data were drawn from five different studies (N = 9,404), including a three-year longitudinal study (n = 2,555), utilizing five divergent occupational samples. Confirmatory factor analysis supported the hypothesized correlated three-factor structure—vigor, dedication, absorption—of both UWES scales. However, while the structure of the UWES-17 did not remain the same across the samples and time, the structure of the UWES-9 remained relatively unchanged. Thus, the UWES-9 has good construct validity and use of the 9-item version can be recommended in future research. Moreover, as hypothesized, Structural Equation Modeling showed high rank-order stabilities for the work engagement factors (between 0.82 and 0.86). Accordingly, work engagement seems to be a highly stable indicator of occupational well-being.

School-Burnout Inventory (SBI) Reliability and Validity

Abstract: This study introduces a measure for school burnout and examines its validity and reliability among students in upper secondary high schools and vocational schools by using confirmatory factor analysis. School-related burnout comprises three dimensions: (a) exhaustion at school, (b) cynicism toward the meaning of school, and (c) sense of inadequacy at school. A total of 1418 (709 girls, 709 boys) adolescents from 13 postcomprehensive schools (6 upper secondary high schools, 7 vocational schools) filled in a questionnaire concerning their school burnout and background variables. The results showed that the three-factor solution, compared to one- or two-factor solutions, fit the data best and also gave the best reliability indices. The three theoretically-derived dimensions of school burnout were closely related but separate constructs. Finally, concurrent validity for the School-Burnout Inventory (SBI) was found when the correlations of depressive symptoms, school engagement, and academic achievement with e...

A preference-based evolutionary algorithm for multi-objective optimization

Abstract: In this paper, we discuss the idea of incorporating preference information into evolutionary multi-objective optimization and propose a preference-based evolutionary approach that can be used as an integral part of an interactive algorithm One algorithm is proposed in the paper At each iteration, the decision maker is asked to give preference information in terms of his or her reference point consisting of desirable aspiration levels for objective functions The information is used in an evolutionary algorithm to generate a new population by combining the fitness function and an achievement scalarizing function In multi-objective optimization, achievement scalarizing functions are widely used to project a given reference point into the Pareto optimal set In our approach, the next population is thus more concentrated in the area where more preferred alternatives are assumed to lie and the whole Pareto optimal set does not have to be generated with equal accuracy The approach is demonstrated by numerical examples

Corticosteroid injections, eccentric decline squat training and heavy slow resistance training in patellar tendinopathy

Abstract: A randomized-controlled single-blind trial was conducted to investigate the clinical, structural and functional effects of peritendinous corticosteroid injections (CORT), eccentric decline squat training (ECC) and heavy slow resistance training (HSR) in patellar tendinopathy. Thirty-nine male patients were randomized to CORT, ECC or HSR for 12 weeks. We assessed function and symptoms (VISA-p questionnaire), tendon pain during activity (VAS), treatment satisfaction, tendon swelling, tendon vascularization, tendon mechanical properties and collagen crosslink properties. Assessments were made at 0 weeks, 12 weeks and at follow-up (half-year). All groups improved in VISA-p and VAS from 0 to 12 weeks (Po0.05). VISA-p and VAS improvements were maintained at follow-up in ECC and HSR but deteriorated in CORT (Po0.05). In CORT and HSR, tendon swelling decreased ( � 13 � 9% and � 12 � 13%, Po0.05) and so did vascularization ( � 52 � 49% and � 45 � 23%, Po0.01) at 12 weeks. Tendon mechanical properties were similar in healthy and injured tendons and were unaffected by treatment. HSR yielded an elevated collagen network turnover. At the half-year follow-up, treatment satisfaction differed between groups, with HSR being most satisfied. Conclusively, CORT has good short-term but poor long-term clinical effects, in patellar tendinopathy. HSR has good short- and long-term clinical effects accompanied by pathology improvement and increased collagen turnover.

Physics at a future Neutrino Factory and super-beam facility

Abstract: The conclusions of the Physics Working Group of the International Scoping Study of a future Neutrino Factory and super-beam facility (the ISS) are presented. The ISS was carried out by the international community between NuFact05, (the 7th International Workshop on Neutrino Factories and Super-beams, Laboratori Nazionali di Frascati, Rome, 21–26 June 2005) and NuFact06 (Ivine, CA, 24–30 August 2006). The physics case for an extensive experimental programme to understand the properties of the neutrino is presented and the role of high-precision measurements of neutrino oscillations within this programme is discussed in detail. The performance of second-generation super-beam experiments, beta-beam facilities and the Neutrino Factory are evaluated and a quantitative comparison of the discovery potential of the three classes of facility is presented. High-precision studies of the properties of the muon are complementary to the study of neutrino oscillations. The Neutrino Factory has the potential to provide extremely intense muon beams and the physics potential of such beams is discussed in the final section of the report.

Evidence for graphene edges beyond zigzag and armchair

Abstract: The edges of nanoscopic objects determine most of their properties. For this reason the edges of honeycomb carbon---always considered either zigzag- or armchairlike---need special attention. In this Brief Report we provide experimental evidence confirming a previous unexpected prediction: zigzag is a metastable edge as its planar reconstruction lowers energy and forms the most stable graphene edge. Our evidence is based on reanalyzing a recent experiment. Since the reconstructed edge, along with other unconventional edges we discuss, has distinct chemical properties, this discovery urges for care in experiments and theory---we must enter the realm beyond zigzag and armchair.

Vacuum Rabi splitting and strong-coupling dynamics for surface-plasmon polaritons and rhodamine 6G molecules.

Abstract: We report on strong coupling between surface-plasmon polaritons (SPP) and Rhodamine 6G (R6G) molecules, with double vacuum Rabi splitting energies up to 230 and 110 meV. In addition, we demonstrate the emission of all three energy branches of the strongly coupled SPP-exciton hybrid system, revealing features of system dynamics that are not visible in conventional reflectometry. Finally, in analogy to tunable-Q microcavities, we show that the Rabi splitting can be controlled by adjusting the interaction time between waveguided SPPs and R6G deposited on top of the waveguide. The interaction time can be controlled with sub-fs precision by adjusting the length of the R6G area with standard lithography methods.

Teacher, peer and parent autonomy support in physical education and leisure-time physical activity: A trans-contextual model of motivation in four nations

Abstract: An extended trans-contextual model of motivation for health-related physical activity was tested in samples from four nations. The model proposes a motivational sequence in which perceived autonomy support from teachers in a physical education (PE) context and from peers and parents in a leisure-time physical activity context predict autonomous motivation, intentions and physical activity behaviour in a leisure-time context. A three-wave prospective correlational design was employed. High-school pupils from Britain, Estonia, Finland and Hungary completed measures of perceived autonomy support from PE teachers, autonomous motivation in both contexts, perceived autonomy support from peers and parents, attitudes, subjective norms, perceived behavioural control and intentions from the Theory of Planned Behaviour (TPB), and measures of behaviour and past behaviour in a leisure-time context. Path-analyses controlling for past behaviour supported trans-contextual model hypotheses across all samples. Effects of perceived autonomy support from peers and parents on leisure-time autonomous motivation were small and inconsistent, while effects on TPB variables were stronger. There was a unique effect of perceived autonomy support from PE teachers on leisure-time autonomous motivation. Findings support the model, which provides an explanation of the processes by which perceived autonomy support from different sources affects health-related physical activity motivation across these contexts.

Depressive symptoms and school burnout during adolescence: evidence from two cross-lagged longitudinal studies.

Abstract: The main purpose of this study was to examine the extent to which middle and late adolescents' depressive symptoms predict their later school burnout and, in turn, the extent to which school burnout predicts depressive symptoms. Drawing on data gathered at ages 15-19 in two-three-wave longitudinal studies, we investigated cross-lagged paths between school burnout and depressive symptoms. In Study 1 the participants were 15-year-old adolescents (Time 1: N = 611, Time 2: N = 614, Time 3: N = 725) who completed the School Burnout Inventory and depressive symptoms twice during their final term of comprehensive school and once after the transition to upper secondary high school or vocational school. In Study 2 the participants were 17-year-old adolescents whose school burnout and depressive symptoms were measured three times annually (Time 1: N = 474, Time 2: N = 412, Time 3: N = 414) during their 3 years of secondary education. Results of both studies revealed moderate stability for both school burnout and depressive symptoms. They also showed that school burnout more strongly predicted subsequent depressive symptoms later on than vice versa. Lastly, they revealed cumulative cycles between school burnout and depressive symptoms.

Statistical language learning in neonates revealed by event-related brain potentials

Abstract: Statistical learning is a candidate for one of the basic prerequisites underlying the expeditious acquisition of spoken language. Infants from 8 months of age exhibit this form of learning to segment fluent speech into distinct words. To test the statistical learning skills at birth, we recorded event-related brain responses of sleeping neonates while they were listening to a stream of syllables containing statistical cues to word boundaries. We found evidence that sleeping neonates are able to automatically extract statistical properties of the speech input and thus detect the word boundaries in a continuous stream of syllables containing no morphological cues. Syllable-specific event-related brain responses found in two separate studies demonstrated that the neonatal brain treated the syllables differently according to their position within pseudowords. These results demonstrate that neonates can efficiently learn transitional probabilities or frequencies of co-occurrence between different syllables, enabling them to detect word boundaries and in this way isolate single words out of fluent natural speech. The ability to adopt statistical structures from speech may play a fundamental role as one of the earliest prerequisites of language acquisition.

Changes in Stress Perception and Coping During Adolescence: The Role of Situational and Personal Factors

Abstract: The present study investigated the interplay between developmental changes in stress and coping during early and late adolescence. Using a longitudinal design, stress perception and coping styles of 200 adolescents in 7 different stressful situations were investigated. Multilevel piecewise latent growth curve models showed that stress perception decreased during late adolescence, whereas active and internal coping increased continuously from ages 12 to 19. Adolescents’ high levels of perceived stress in a particular situation were associated with a high level of active coping but a low level of internal coping in that same situation. Withdrawal was associated with high levels of perceived stress, independent of situation. Developmental changes in individual adolescents’ stress perception and coping were in most cases situation specific.

Nonporous Organic Solids Capable of Dynamically Resolving Mixtures of Diiodoperfluoroalkanes

Abstract: Halogen bonding has increasingly facilitated the assembly of diverse host-guest solids. Here, we show that a well-known class of organic salts, bis(trimethylammonium) alkane diiodides, can reversibly encapsulate α,ω-diiodoperfluoroalkanes (DIPFAs) through intermolecular interactions between the host9s I– anions and the guest9s terminal iodine substituents. The process is highly selective for the fluorocarbon that forms an I–···I(CF2)mI···I– superanion that is matched in length to the chosen dication. DIPFAs that are 2 to 12 carbons in length (common industrial intermediates) can thereby be isolated from mixtures by means of crystallization from solution upon addition of the dissolved size-matched ionic salt. The solid-state salts can also selectively capture the DIPFAs from the vapor phase, yielding the same product formed from solution despite a lack of porosity of the starting lattice structure. Heating liberates the DIPFAs and regenerates the original salt lattice, highlighting the practical potential for the system in separation applications.

Change in Newcomers' Supervisor Support and Socialization Outcomes After Organizational Entry

Abstract: Using a four-wave longitudinal research design and a latent growth modeling approach, we modeled change in newcomers' perceived supervisor support and socialization outcomes (role clarity, work mas...

An adoption model for mobile banking in Ghana

Abstract: The impact of social and cultural factors on the adoption of technology still requires much research. To investigate it more fully, we examine the reasons for the adoption and non-adoption of mobile banking in Ghana. Through a survey of 271 people in Ghana, it has been found that social and cultural factors in the form of perceived credibility, facilitating conditions, perceived elitisation and demographic factors do play a significant role in adoption decisions. It has been found that elitisation of technology and services can be a positive influence for adopters whilst being a negative influence for non-adopters. In addition, perceived credibility and facilitating conditions also influence attitudes towards the technology. When these factors are added to a range of demographic factors, the impact of the social and cultural features of the context of studies can be seen as significant.

Self-reported sleep duration and cognitive functioning in the general population

Abstract: This study investigated the relationship between self-reported sleep factors (sleep duration, insomnia, use of sleeping medicine, probable sleep apnoea and feelings of fatigue and tiredness) with cognitive functioning in 5177 people aged 30 years or older from a cross-sectional representative sample of the adult population in Finland (The Finnish Health 2000 Survey). Previous studies have indicated a U-shaped association between increased health risks and sleep duration; we hypothesized a U-shaped association between sleep duration and cognitive functioning. Objective cognitive functioning was assessed with tasks derived from the Consortium to Establish a Registry for Alzheimer's Disease test battery (verbal fluency, encoding and retaining verbal material). Subjective cognitive functioning and sleep-related factors were assessed with questionnaires. Health status was assessed during a health interview. Depressive and alcohol use disorders were assessed with the Composite International Diagnostic Interview. Medication was recorded during the health examination. Short and long sleep duration, tiredness and fatigue were found to be associated with both objectively assessed and self-reported decreased cognitive functioning. The association was stronger between sleep factors and subjective cognitive function than with objective cognitive tests. These data suggest that self-reported habitual short and long sleep duration reflect both realization of homeostatic sleep need and symptom formation in the context of the individual's health status.

Hearing as a Predictor of Falls and Postural Balance in Older Female Twins

Abstract: BACKGROUND: The purpose of the present study was to examine, first, whether hearing acuity predicts falls and whether the potential association is explained by postural balance and, second, to examine whether shared genetic or environmental effects underlie these associations. METHODS: Hearing was measured using a clinical audiometer as a part of the Finnish Twin Study on Aging in 103 monozygotic and 114 dizygotic female twin pairs aged 63-76 years. Postural balance was indicated as a center of pressure (COP) movement in semitandem stance, and participants filled in a fall-calendar daily for an average of 345 days after the baseline. RESULTS: Mean hearing acuity (better ear hearing threshold level at 0.5-4 kHz) was 21 dB (standard deviation [SD] 12). Means of the COP velocity moment for the best to the poorest hearing quartiles increased linearly from 40.7 mm(2)/s (SD 24.4) to 52.8 mm(2)/s (SD 32.0) (p value for the trend = .003). Altogether 199 participants reported 437 falls. Age-adjusted incidence rate ratios (IRRs) for falls, with the best hearing quartile as a reference, were 1.2 (95% confidence interval [CI] = 0.4-3.8) in the second, 4.1 (95% CI = 1.1-15.6) in the third, and 3.4 (95% CI = 1.0-11.4) in the poorest hearing quartiles. Adjustment for COP velocity moment decreased IRRs markedly. Twin analyses showed that the association between hearing acuity and postural balance was not explained by genetic factors in common for these traits. CONCLUSION: People with poor hearing acuity have a higher risk for falls, which is partially explained by their poorer postural control. Auditory information about environment may be important for safe mobility. Language: en

Kadanoff-Baym approach to quantum transport through interacting nanoscale systems: From the transient to the steady-state regime

Abstract: We propose a time-dependent many-body approach to study the short-time dynamics of correlated electrons in quantum transport through nanoscale systems contacted to metallic leads. This approach is based on the time propagation of the Kadanoff-Baym equations for the nonequilibrium many-body Green's function of open and interacting systems out of equilibrium. An important feature of the method is that it takes full account of electronic correlations and embedding effects in the presence of time-dependent external fields, while at the same time satisfying the charge conservation law. The method further extends the Meir-Wingreen formula to the time domain for initially correlated states. We study the electron dynamics of a correlated quantum wire attached to two-dimensional leads exposed to a sudden switch on of a bias voltage using conserving many-body approximations at Hartree-Fock, second Born and GW level. We obtain detailed results for the transient currents, dipole moments, spectral functions, charging times, and the many-body screening of the quantum wire as well as for the time-dependent density pattern in the leads, and we show how the time dependence of these observables provides a wealth of information on the energy level structure of the quantum wire out of equilibrium. For moderate interaction strengths the second Born and GW results are in excellent agreement at all times. We find that many-body effects beyond the Hartree-Fock approximation have a large effect on the qualitative behavior of the system and lead to a bias-dependent gap closing and quasiparticle broadening, shortening of the transient times and washing out of the step features in the current-voltage curves.

Recovery experiences as moderators between psychosocial work characteristics and occupational well-being

Abstract: This study examined the direct and moderator roles of recovery experiences (psychological detachment from work, relaxation, mastery, and control) in the relationship between psychosocial work characteristics (i.e. time demands, job control, and justice of the supervisor) and occupational well-being (need for recovery, job exhaustion, and work engagement). The study was conducted among 527 Finnish employees from several occupational sectors who were employed in a variety of different jobs. Of the employees, 53% were women and the average age was 42.4 years. The moderated hierarchical regression analyses showed that psychological detachment and mastery were protective mechanisms against increased need for recovery in a situation of lack of job control. Also, relaxation protected against increased job exhaustion under high time demands. In addition, recovery experiences – psychological detachment and mastery in particular – had direct links to occupational well-being. Altogether, the study findings ...

Subjective health, symptom load and quality of life of children and adolescents in Europe.

Abstract: Objectives: To examine cross-cultural differences in the prevalence of school children's subjective health types and the pattern of socio-demographic and socio-economic differences.

Body weight dissatisfaction and communication with parents among adolescents in 24 countries: international cross-sectional survey.

Abstract: Parents have significant influence on behaviors and perceptions surrounding eating, body image and weight in adolescents. The aim of this study was to examine the prevalence of body weight dissatisfaction, difficulty in communication with the parents and the relationship between communication with parents and adolescents' dissatisfaction with their body weight (dieting or perceived need to diet). Survey data were collected from adolescents in 24 countries and regions in Europe, Canada, and the USA who participated in the cross-sectional 2001/2002 Health Behaviour of School-Aged Children (HBSC) study. The association between communication with parents and body weight dissatisfaction was examined using binary logistic regression analysis. Body weight dissatisfaction was highly prevalent and more common among girls than boys, among overweight than non-overweight, and among older adolescents than younger adolescents. Difficulty in talking to father was more common than difficulty in talking to mother in all countries and it was greater among girls than among boys and increased with age. Difficulties in talking to father were associated with weight dissatisfaction among both boys and girls in most countries. Difficulties in talking to mother were rarely associated with body weight dissatisfaction among boys while among girls this association was found in most countries. The findings suggest that enhanced parent communication might contribute in most countries to less body dissatisfaction in girls and better communication with the father can help avoiding body weight dissatisfaction in boys. Professionals working with adolescents and their families should help adolescents to have a healthy weight and positive body image and promote effective parent – adolescent communication.

Acute and long-term effects of resistance exercise with or without protein ingestion on muscle hypertrophy and gene expression.

Abstract: The effects of timed ingestion of high-quality protein before and after resistance exercise are not well known. In this study, young men were randomized to protein (n = 11), placebo (n = 10) and control (n = 10) groups. Muscle cross-sectional area by MRI and muscle forces were analyzed before and after 21 weeks of either heavy resistance training (RT) or control period. Muscle biopsies were taken before, and 1 and 48 h after 5 × 10 repetition leg press exercise (RE) as well as 21 weeks after RT. Protein (15 g of whey both before and after exercise) or non-energetic placebo were provided to subjects in the context of both single RE bout (acute responses) as well as each RE workout twice a week throughout the 21-week-RT. Protein intake increased (P ≤ 0.05) RT-induced muscle cross-sectional area enlargement and cell-cycle kinase cdk2 mRNA expression in the vastus lateralis muscle suggesting higher proliferating cell activation response with protein supplementation. Moreover, protein intake seemed to prevent 1 h post-RE decrease in myostatin and myogenin mRNA expression but did not affect activin receptor IIb, p21, FLRG, MAFbx or MyoD expression. In conclusion, protein intake close to resistance exercise workout may alter mRNA expression in a manner advantageous for muscle hypertrophy.