Showing papers by "University of Jyväskylä published in 2004"
TL;DR: In this article, the developmental dynamics of mathematical performance during children's transition from preschool to grade 2 and the cognitive antecedents of this development were investigated, and the results indicated that math performance showed high stability and increasing variance over time.
Abstract: This study investigated the developmental dynamics of mathematical performance during children's transition from preschool to Grade 2 and the cognitive antecedents of this development. 194 Finnish children were examined 6 times according to their math performance, twice during each year across a 3-year period. Cognitive antecedents, that is, counting ability, visual attention, metacognitive knowledge, and listening comprehension, were tested at the first measurement point. The results indicated that math performance showed high stability and increasing variance over time. Moreover, the growth of math competence was faster among those who entered preschool with an already high level of mathematical skills. The initial level of math performance, as well as its growth, was best predicted by counting ability.
703 citations
TL;DR: The genic capture hypothesis as discussed by the authors offers a resolution to the question of how genetic variation in male sexually selected traits is maintained in the face of strong female preferences, and it has been shown that male display traits are costly to produce and hence depend upon overall condition, which itself is dependent upon genes at many loci.
Abstract: The genic capture hypothesis offers a resolution to the question of how genetic variation in male sexually selected traits is maintained in the face of strong female preferences. The hypothesis is that male display traits are costly to produce and hence depend upon overall condition, which itself is dependent upon genes at many loci. Few attempts have been made to test the assumptions and predictions of the genic capture hypothesis rigorously and, in particular, little attention has been paid to determining the genetic basis of condition. Such tests are crucial to our understanding of the maintenance of genetic variation and in the evaluation of recent models that propose a role for sexual selection in the maintenance of sex. Here, we review approaches to testing the link between genetically determined condition and levels of sexual trait expression and consider the probable importance of deleterious mutations.
532 citations
TL;DR: A detailed analysis of the class of absolutely minimizing functions in Euclidean spaces and the relationship to the infinity Laplace equation is given in this article, where the authors also discuss the relationship between absolute minimization and the Laplace Equation.
Abstract: A detailed analysis of the class of absolutely minimizing functions in Euclidean spaces and the relationship to the infinity Laplace equation
379 citations
TL;DR: It is suggested that α2β1 integrin is a functional cellular receptor for type I collagen fibrils, whereas α1β1 Integrin may only effectively bind type I gelatin monomers.
351 citations
TL;DR: The effects of variable predators on models that combine positive frequency‐ dependent, frequency‐independent, and negative frequency‐dependent predation are explored and it is shown that weak signaling of aposematic species can evolve if predators vary in their tendency to attack defended prey.
Abstract: Conspicuous warning signals of unprofitable prey are a defense against visually hunting predators They work because predators learn to associate unprofitability with bright coloration and because strong signals are detectable and memorable However, many species that can be considered defended are not very conspicuous; they have weak warning signals This phenomenon has previously been ignored in models and experiments In addition, there is significant within- and among-species variation among predators in their search behavior, in their visual, cognitive, and learning abilities, and in their resistance to defenses In this article we explore the effects of variable predators on models that combine positive frequency-dependent, frequency-independent, and negative frequency-dependent predation and show that weak signaling of aposematic species can evolve if predators vary in their tendency to attack defended prey
280 citations
TL;DR: It seemed that minor depression among the elderly was most typically an episodic phenomenon, with a statistically significant increase in the figures for women particularly from age 80 to 85 years.
278 citations
TL;DR: The authors examined the longitudinal relations between work-to-family conflict and self-reported satisfaction and well-being in the domains of work (job satisfaction), family (marital satisfaction, parental distress) as well as overall (psychological and physical) symptoms.
Abstract: The present study produced new knowledge about gender differences with respect to work-to-family conflict and its longitudinal relations with indicators of satisfaction and well-being. The study examined the longitudinal relations between work-to-family conflict and self-reported satisfaction and well-being in the domains of work (job satisfaction), family (marital satisfaction, parental distress) as well as overall (psychological and physical) symptoms. Data were obtained from a random sample of Finnish men (n=208) and women (n=218) who were employed and had either a partner or/and children. A survey was conducted at two points in time, in 1999 (Time 1), and one year later, in 2000 (Time 2). The results revealed that, among women, work-to-family conflict perceived at Time 1 significantly predicted job dissatisfaction, parental distress as well as psychological symptoms at Time 2. However, among men, a low level of satisfaction or well-being at Time 1 (marital dissatisfaction, parental distress, psycholog...
263 citations
TL;DR: Data indicate that players entering the season with low circulating concentrations of T and elevated levels of C can experience reductions in performance during a season, with performance decrements exacerbated in starters over nonstarters.
Abstract: As a consequence of the physiological demands experienced during a competitive soccer season, the antagonistic relationship between anabolic and catabolic processes can affect performance. Twenty-five male collegiate soccer players were studied throughout a season (11 weeks) to investigate the effects of long-term training and competition. Subjects were grouped as starters (S; n = 11) and nonstarters (NS; n = 14). Measures of physical performance, body composition, and hormonal concentrations (testosterone [T] and cortisol [C]) were assessed preseason (T1) and 5 times throughout the season (T2-T6). Starters and NS participated in 83.06% and 16.95% of total game time, respectively. Nonstarters had a significant increase (+1.6%) in body fat at T6 compared to T1. Isokinetic strength of the knee extensors (1.05 rad.sec(-1)) significantly decreased in both S (-12%) and NS (-10%; p < or = 0.05) at T6. Significant decrements in sprint speed (+4.3%) and vertical jump (-13.8%) were found at T5 in S only. Though within normal ranges (10.4-41.6 nmol.L(-1)), concentrations of T at T1 were low for both groups, but increased significantly by T6. Concentrations of C were elevated in both groups, with concentrations at the high end of the normal range (normal range 138-635 nmol.L(-1)) at T1 and T4 in NS and T4 in S, with both groups remaining elevated at T6. Data indicate that players entering the season with low circulating concentrations of T and elevated levels of C can experience reductions in performance during a season, with performance decrements exacerbated in starters over nonstarters. Soccer players should therefore have a planned program of conditioning that does not result in an acute overtraining phenomenon prior to preseason (e.g., young players trying to get in shape quickly in the 6 to 8 weeks in the summer prior to reporting for preseason camp). The detrimental effects of inappropriate training do not appear to be unloaded during the season and catabolic activities can predominate.
243 citations
TL;DR: High resolution UV-photoelectron spectra of cold mass selected Cun, Agn, and Aun- with n=53-58 show that only Cu55- and Ag55- exhibit highly degenerate states, a direct consequence of their icosahedral symmetry, as confirmed by density functional theory calculations.
Abstract: We present high resolution UV-photoelectron spectra of cold mass selected ${\mathrm{C}\mathrm{u}}_{n}^{\ensuremath{-}}$, ${\mathrm{A}\mathrm{g}}_{n}^{\ensuremath{-}}$, and ${\mathrm{A}\mathrm{u}}_{n}^{\ensuremath{-}}$ with $n=53--58$. The observed electron density of states is not the expected simple electron shell structure, but is strongly influenced by electron-lattice interactions. Only ${\mathrm{C}\mathrm{u}}_{55}^{\ensuremath{-}}$ and ${\mathrm{A}\mathrm{g}}_{55}^{\ensuremath{-}}$ exhibit highly degenerate states. This is a direct consequence of their icosahedral symmetry, as is confirmed by density functional theory calculations. Neighboring sizes exhibit perturbed electronic structures, as they are formed by removal or addition of atoms to the icosahedron and therefore have lower symmetries. Gold clusters in the same size range show completely different spectra with almost no degeneracy, which indicates that they have structures of much lower symmetry. This behavior is related to strong relativistic bonding effects in gold, as demonstrated by ab initio calculations for ${\mathrm{A}\mathrm{u}}_{55}^{\ensuremath{-}}$.
234 citations
TL;DR: In this article, the authors focused on studying diffusion and adopters of mobile banking services and analyzed the influence of certain demographic characteristics and the preferred communication mode of customers on the adoption and future usage of mobile bank services.
Abstract: Technological advancement has challenged the providers of financial services; the very nature of selling and buying financial services has changed. Mobile devices are among the newest channels to conduct banking electronically. This paper focuses on studying diffusion and adopters of mobile banking services. Previous research has identified the typical characteristics of a potential adopter in the electronic services era; this paper explores some contradictory empirical findings drawn from a mobile banking survey. The results provide an indication of the characteristics of potential subsequent adopters of mobile banking, and of differences between user segments. Consequently, the authors are able to comment on the influence of certain demographic characteristics and the preferred communication mode of customers on the adoption and future usage of mobile banking services. The quantitative survey that sheds more light on this researched issue employed a traditional method of postal questionnaire. The data were collected in Finland during May–July 2002 and include 1,253 survey responses.
228 citations
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TL;DR: In this paper, the authors report a survey (n=713) on the views of Finnish consumers about ethics in trade and investigate consumers' willingness to promote business ethics, as well as the obstacles to ethical consumption.
Abstract: Business ethics and corporate social responsibility have gained more attention in recent years. However, the consumers' perspective on ethics is still a little researched area. This study reports a survey (n=713) on the views of Finnish consumers about ethics in trade. Consumers' willingness to promote business ethics, as well as the obstacles to ethical consumption, are investigated. The results of the study show that while the majority of the respondents regard business ethics as important, this attitude does not translate into their choice behavior. Consumers are uncertain about which products and firms follow ethical rules and which do not. The most important obstacles to ethical consumption were difficulties in obtaining information, problems in product availability and high prices of ethical products.
TL;DR: Theoretical approaches to one-dimensional and quasi-one-dimensional quantum rings with a few electrons are reviewed in this article, where the energy spectrum of the many-body states can be described by a rotation-vibration spectrum of a Wigner molecule of localized electrons, combined with the spin state determined from an effective antiferromagnetic Heisenberg Hamiltonian.
Abstract: Theoretical approaches to one-dimensional and quasi-one-dimensional quantum rings with a few electrons are reviewed. Discrete Hubbard-type models and continuum models are shown to give similar results governed by the special features of the one-dimensionality. The energy spectrum of the many-body states can be described by a rotation–vibration spectrum of a “Wigner molecule” of “localized” electrons, combined with the spin-state determined from an effective antiferromagnetic Heisenberg Hamiltonian. The persistent current as a function of the magnetic flux through the ring shows periodic oscillations arising from the “rigid rotation” of the electron ring. For polarized electrons the periodicity of the oscillations is always the flux quantum Φ 0 . For nonpolarized electrons the periodicity depends on the strength of the effective Heisenberg coupling and changes from Φ 0 first to Φ 0 /2 and eventually to Φ 0 / N when the ring gets narrower.
TL;DR: Impairments and their impact on activities were frequent and constant and there is an urgent need for developing rehabilitation protocols for breast cancer patients.
Abstract: Objective: To describe the impairments of upper body and limbs, activity limitations and participation restrictions 6 and12monthsafter operation forbreast cancer andto examine the impact of impairments on activity limitations. Design: A prospective survey 6 and 12 months after operation. Patients: Ninety-six breast cancer patients. Methods: A questionnaire for assessing the impairments, activity limitations and participation restrictions was developed. Results:The mostcommonimpairments 6monthsafter operation were breast and axilla scar tightness, axilla oedema and neck-shoulder pain. At 12-month follow-up the breast scar tightness (p = 0.008) and axilla oedema (p = 0.023) decreased, and limb ache (p = 0.005) increased significantly. The most limiting impairments were axilla oedema and limb numbness 6 months after operation, and at 12-month follow-up axilla oedema. Lifting, carrying and reaching out caused worsening of impairments to more than half of the respondents at 6-month follow-up. Regression analysis showed that many impairments together were determinants of activity limitations and sleep impairment. Participation restrictions were constant. Respondents had not given up participation in activities in the home, but some had abandoned leisure activities and felt that their work ability had decreased. Conclusion: Impairments and their impact on activities were frequent and constant. There is an urgent need for developing rehabilitation protocols for breast cancer patients.
TL;DR: Both the group differences and the predictive associations to later language and reading ability strengthened as a function of increasing age, and the spectrum of significant correlations wider in the at-risk group.
Abstract: Children at risk for familial dyslexia (n=107) and their controls (n=93) have been followed from birth to school entry in the Jyvaskyla Longitudinal study of Dyslexia (JLD) on developmental factors linked to reading and dyslexia. At the point of school entry, the majority of the at-risk children displayed decoding ability that fell at least 1 SD below the mean of the control group. Measures of speech processing were the earliest indices to show both group differences in infancy and also significant predictive associations with reading acquisition. A number of measures of language, including phonological and morphological skill collected repeatedly from age three, revealed group differences and predictive correlations. Both the group differences and the predictive associations to later language and reading ability strengthened as a function of increasing age. The predictions, however, tend to be stronger and the spectrum of significant correlations wider in the at-risk group. These results are crucial to early identification and intervention of dyslexia in at-risk children.
TL;DR: Numerical experiments show that the operator splitting methodology is much more efficient than the projected SOR, while the accuracy of both methods are similar.
TL;DR: In this paper, the authors report a survey (n = 713) on the views of Finnish consumers about ethics in trade and investigate consumers' willingness to promote business ethics as well as the obstacles to ethical consumption.
Abstract: Business ethics and corporate social responsibility have gained more attention in recent years. However, the consumers’ perspective on ethics is still a little researched area. This study reports a survey ( n = 713) on the views of Finnish consumers about ethics in trade. Consumers’ willingness to promote business ethics as well as the obstacles to ethical consumption are investigated. The results of the study show that while the majority of the respondents regard business ethics as important, this attitude does not translate into their choice behaviour. Consumers are uncertain about which products and firms follow ethical rules and which do not. The most important obstacles to ethical consumption were difficulties in obtaining information, problems in product availability and high prices of ethical products.
TL;DR: Evidence is presented that repeated and prolonged passive muscle stretching can lead to some modification of material behavior of the aponeurosis-tendon system, such as stress relaxation and/or plastic deformation, which seems to affect proprioceptive feedback and, therefore, the motor unit activation in proportion to the contractile failure.
Abstract: Experiments were carried out to examine interaction between mechanical changes of the muscle-tendon unit and reduced reflex sensitivity after repeated and prolonged passive muscle stretching (RPS). There is some evidence that this interaction might be relevant also during active stretch-shortening cycle type of fatigue tasks. The results demonstrated a clear deterioration of voluntarily and electrically induced muscle contractions after RPS. Maximal voluntary contraction (MVC), average electromyographic activities of the gastrocnemius and soleus muscles, and maximal twitch contraction decreased on average by 13.8, 10.4, 7.6, and 16.8%, respectively. In addition, there was a 14% lengthening in the total duration of the twitch. MVCs measured at different ankle joint angles revealed a downward and rightward shift in the torque-fascicle length curve after RPS. Interestingly, there was a crossing in the torque-fascicle length curves while measured at different activation levels but at the same joint angle before and after RPS. Even though no changes were observed in the activation level during MVCs, all the reflex parameters showed a clear reduction after RPS. This study presents evidence that repeated and prolonged passive muscle stretching can lead to some modification of material behavior of the aponeurosis-tendon system, such as stress relaxation and/or plastic deformation. In addition, altered material properties seem to affect proprioceptive feedback and, therefore, the motor unit activation in proportion to the contractile failure.
TL;DR: In this paper, the trajectories of preschool and first-grade children's development of reading skills, as well as the cognitive and social antecedents of that development were investigated.
Abstract: This study investigated the trajectories of preschool and first-grade children's development of reading skills, as well as the cognitive and social antecedents of that development. One-hundred and ninety-six 5- to 6-year-old children were tested in October and April of their preschool year and again in the first grade. Data included measures of reading ability and its cognitive and social antecedents, which were analyzed using Simplex and Piecewise Growth Curve Modeling. The results showed that during the preschool year individual differences in reading grew larger and that this growth was faster among those who entered preschool with well-developed skills. However, during the first grade individual differences in reading diminished. The results suggest that systematic reading instruction in primary school education is more beneficial for children with less developed literacy skills, whereas children with more developed reading skills gain relatively less from reading instruction in the first grade.
ESTE ESTUDIO investigo el curso evolutivo de las habilidades de lectura en ninos de pre-escolar y escuela primaria, asi como los antecedentes cognitivos y sociales de dicho desarrollo. Ciento noventa y seis ninos de 5 a 6 anos fueron evaluados en octubre y abril en pre-escolar y nuevamente en primer grado. Los datos incluyeron medidas de habilidad de lectura y sus antecedentes cognitivos y sociales y fueron analizados usando el metodo “Simplex and Piecewise Growth Curve Modeling.” Los resultados mostraron que, durante el ano de pre-escolar las diferencias individuales en lectura aumentaron y que este crecimiento fue mas rapido entre aquellos que entraron a preescolar con habilidades bien desarrolladas. Sin embargo, durante el primer grado, las diferencias individuales en lectura disminuyeron. Los resultados sugieren que la ensenanza sistematica de la lectura en la educacion primaria es mas beneficiosa para los ninos con habilidades de lectoescritura menos desarrolladas; en tanto que los ninos con habilidades de lectura mas desarrolladas obtienen relativamente menos beneficios de la ensenanza de la lectura en primer grado.
DIESE STUDIE untersuchte die Gedankenbahnen bei der Entwicklung von Leseleistungen von Kindern in der Vorschule und der ersten Klasse, sowie die kognitiven und sozialen Antezedentien dieser Entwicklung. Einhundertsechsundneunzig funf bis sechs Jahre alte Kinder wurden im Oktober und im April wahrend ihres Vorschuljahres und dann nochmals in der ersten Klasse gepruft. Die Daten umfassten das Ermessen der Lesefahigkeit und deren kognitiven und sozialen Antezedentien, die mittels Nutzung der “Simplex- und Piecewise” Wachstumsmodellkurven analysiert wurden. Die Ergebnisse zeigten, das sich wahrend des Vorschuljahres individuelle Differenzen im Lesen verbesserten und das dieser Zuwachs bei jenen, die mit bereits gut entwickelten Leistungen in der Vorschule begannen, schneller vonstatten ging. Jedoch verringerten sich individuelle Differenzen wahrend der ersten Klasse. Die Ergebnisse empfehlen, das systematische Leseanweisungen in der Grundschulerziehung fur Kinder mit geringer entwickelten Leseleistungen vorteilhafter sind, wohingegen Kinder mit besser entwickelten Leseleistungen relativ geringfugig von den Leseanweisungen in der ersten Klasse profitieren.
TL;DR: Bile acid-based structures have become increasingly important in different fields of chemistry over recent years, having found applications in pharmacology, supramolecular chemistry and nanoscience as mentioned in this paper.
TL;DR: The results show that natural selection acts against eyespots in the dry season, favouring crypsis, whereas in the wet season it may favour eyespots as deflective patterns.
Abstract: The butterfly Bicyclus anynana exhibits phenotypic plasticity involving the wet-season phenotype, which possesses marginal eyespots on the ventral surface of the wings, and the dry-season form, which lacks these eyespots. We examined the adaptive value of phenotypic plasticity of B. anynana in relation to the defence mechanisms of crypsis and deflection. We assessed the visibility differences between spotless and spotted butterflies against backgrounds of brown (dry season) or green (wet season) leaves. Spotless butterflies were highly cryptic and less predated by adult bird predators than were spotted ones when presented against brown leaf litter. However, the advantage of crypsis disappeared in the wet-season habitat as both forms were equally visible. In later experiments, naive birds presented with resting butterflies in the wet-season habitat tended to learn more rapidly to capture spotless butterflies, suggesting a slight selective advantage of possessing eyespots. Moreover, marginal eyespots increased significantly the escape probability of butterflies that were attacked by naive birds compared to those attacked by adult birds, although there were no differences in prey capture success within naive predators. Our results show that natural selection acts against eyespots in the dry season, favouring crypsis, whereas in the wet season it may favour eyespots as deflective patterns.
TL;DR: The four collagen receptor integrins, alpha1beta1, alpha2 beta1,alpha10beta1 and alpha11beta1 are discussed, which form a structurally and functionally distinct subgroup when compared to other members of the integrin family.
TL;DR: Investigating the influence of parasites on the susceptibility of fish to artificial aerial predators and the ability of D. spathaceum eye flukes to alter fish behaviour suggested that infected fish should be easier prey for gulls and terns.
TL;DR: A high level of psychological control exercised by mothers predicted their children's slow progress in mathematics, however, this impact was particularly evident among those children whose mothers reported a highlevel of affection.
Abstract: This study investigated the extent to which mothers' psychological control predicts their children's mathematical performance during the children's transition from preschool to primary school over and above the impact of maternal affection and behavioral control. Also investigated was the extent to which maternal affection and behavioral control moderate the impact of mothers' psychological control. Children 5-6 years old at baseline (N=196) were followed up 6 times to measure their performance in mathematics over a 3-year period from preschool to 2nd grade. Mothers were asked to fill in a questionnaire measuring their parenting styles once every year over the 3-year period. A high level of psychological control exercised by mothers predicted their children's slow progress in mathematics. However, this impact was particularly evident among those children whose mothers reported a high level of affection. No evidence was found that children's mathematical performance had any effect on their mothers' parenting styles.
TL;DR: It is suggested that balance training based on visual feedback improves the balance control in frail elderly women living in residential care, also enhancing the performance of functional balancing tasks relevant to daily living.
Abstract: Background: Balance training programs have not shown consistent results among older adults, and it remains unclear how different training methods can be adapted to frail elderly peo
TL;DR: The melting point determination is a sensitive method for the characterization of crystal quality but it cannot be used alone for the identification of sugar samples in all cases, therefore, the melting point method should be validated for different sugars.
TL;DR: It was evident in that average breeding success declined over the years, but no declining trend was detected in the best (and most preferred) sites, and the data set is inconclusive with respect to the public information hypothesis, i.e. whether birds use conspecific cues of breeding success when settling in a new site.
Abstract: Summary 1. The hypothesis of site-dependent population regulation predicts that birds utilize available nesting sites in a pre-emptive (ideal despotic) manner, leading to density dependence in heterogeneous habitats as poorer sites are used at higher population densities. At small population sizes adaptive site choice protects populations against fluctuations (the buffer effect). 2. Common guillemots Uria aalge (Pontoppidan) breed at high density on sea-cliffs. The population breeding on the Isle of May, Scotland increased by 60% between 1981 and 2000. A good nest-site is a prerequisite for successful breeding and there is much competition for the best sites. Throughout this period, site use correlated with two measures of site quality, and photographs taken in 1936 show that this pattern has been extremely stable. 3. The data indicate declining quality of sites that remain available as the population has increased. Site-dependent regulation was evident in that average breeding success declined over the years, but no declining trend was detected in the best (and most preferred) sites. 4. An individual guillemot generally uses the same nest-site from year to year, but a minority move, usually less than 2 m, between breeding seasons. These movements can be involuntary or voluntary. Involuntarily moving birds that had occupied very good sites before moving often spent several years as non-breeders (floaters) close to their previous site before breeding again, and then occupied poorer sites. Voluntarily moving birds significantly improved their site quality by moving. 5. Birds responded both to the physical site characteristics and to their own experience (breeding failure) when abandoning a site. Their behaviour thus combined aspects of the ‘win-stay, lose-switch’ strategy with direct assessment of site quality. Our data set is inconclusive with respect to the public information hypothesis, i.e. whether birds use conspecific cues of breeding success when settling in a new site.
TL;DR: This paper analyzed findings on the theme of teacher professionalism derived from re-interviewing a sample of English and Finnish teachers in 2001 as a follow-up to earlier ethnographic research in six schools in each country during 1994-1996.
Abstract: Policy‐makers' conceptions of teacher professionalism currently differ markedly in England and Finland. In England they are shaped by agendas associated with the drive to raise standards and ‘commercialized professionalism’ whilst in Finland they are influenced by notions of ‘teacher empowerment’. This article analyses findings on the theme of teacher professionalism derived from re‐interviewing a sample of English and Finnish teachers in 2001 as a follow‐up to earlier ethnographic research in six schools in each country during 1994–1996. Issues of professionalism are addressed through three broad themes: the impact of curriculum and pedagogical reforms; working together to implement these reforms; and accountability and control. It is argued that in each country teachers' conceptions of their professionalism were undergoing reconstruction. These conceptions were shaped by past and present ideology, policy and practice and displayed multiple and situational dimensions.
TL;DR: The results point to the importance of social relations in the prevention of functional decline in older adults.
Abstract: Objectives This study examines whether aspects of social relations at baseline are related to functional decline at 5-year follow-up among nondisabled old men and women. Methods The investigation is based on baseline and follow-up data on 651 nondisabled 75-year-old persons in Jyvaskyla (Finland) and Glostrup (Denmark). The analyses are performed separately for men and women. Possible selection problems were considered by using three outcome measures: first, functional decline among the survivors (n = 425); second, functional decline, including death, assuming that death is part of a general decline pattern (n = 565); and third, mortality (n = 651). Social relations were measured at baseline by several items focusing on the structure and function of the social network. Results In men, no weekly telephone contact was related to functional decline and mortality. Among women, less than weekly telephone contact, no membership in a retirement club, and not sewing for others were significantly related to functional decline and mortality. The associations were stronger when the dead were included in the outcome measure. Discussion The results point to the importance of social relations in the prevention of functional decline in older adults.
TL;DR: The results suggested that muscle strength is under a genetic regulation, but also environmental effects have a significant role in explaining the variability in the muscle strength.
Abstract: The purpose of the present study was to examine genetic and environmental effects on maximal isometric handgrip, knee extension, and ankle plantar flexion strength. In addition, we wanted to investigate whether the strength of these three muscle groups shares a genetic component or whether the genetic effect is specific for each muscle group. Muscle strength was measured as part of the Finnish Twin Study on Aging in 97 monozygotic (MZ) and 102 dizygotic (DZ) female twin pairs, aged 63-76 yr. The MZ and DZ individuals did not differ from each other in age, body height, weight, or self-related health. The age-adjusted pairwise (intraclass) correlations of the MZ and DZ twins were, respectively, 0.462 and 0.242 in knee extension, 0.435 and 0.345 in handgrip, and 0.512 and 0.435 in ankle plantar flexion strength. The multivariate genetic analysis showed that handgrip and knee extension strength shared a genetic component, which accounted for 14% (95% confidence interval: 4-28%) of the variance in handgrip strength and 31% (95% confidence interval: 18-45%) in knee extension strength. The influence of genetic effects on ankle plantar flexion strength was minor and not significant. Furthermore, these three muscle groups had a nongenetic familial effect in common and nonshared environmental effects in common. The results suggested that muscle strength is under a genetic regulation, but also environmental effects have a significant role in explaining the variability in the muscle strength.
TL;DR: It is suggested that interspecific aggression may have caused character displacement in wing spot size of Calopteryx splendens, because the intensity of aggression towards large‐spotted males is likely to increase with relative abundance of C. virgo males.
Abstract: Problems in species recognition are thought to affect the evolution of secondary sexual characters mainly through avoidance of maladaptive hybridization. Another, but much less studied avenue for the evolution of sexual characters due to species recognition problems is through interspecific aggression. In the damselfly, Calopteryx splendens, males have pigmented wing spots as a sexual character. Large-spotted males resemble males of another species, Calopteryx virgo, causing potential problems in species recognition. In this study, we investigate whether there is character displacement in wing spot size and whether interspecific aggression could cause this pattern. We found first that wing spot size of C. splendens in populations decreased with increasing relative abundance of C. virgo. Secondly, C. virgo males were more aggressive towards large- than small-spotted C. splendens males. Thirdly, in interspecific contests C. virgo males had better territory holding ability than C. splendens males. These results suggest that interspecific aggression may have caused character displacement in wing spot size of C. splendens, because the intensity of aggression towards large-spotted males is likely to increase with relative abundance of C. virgo males. Thus, interspecific aggression may be an evolutionarily significant force that is able to cause divergence in secondary sexual characters.