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Developmental Differences (developmental + difference)
Selected AbstractsGenetic, Temporal and Developmental Differences Between Melatonin Rhythm Generating Systems in the Teleost Fish Pineal Organ and RetinaJOURNAL OF NEUROENDOCRINOLOGY, Issue 4 2003J. Falcón Abstract Complete melatonin rhythm generating systems, including photodetector, circadian clock and melatonin synthesis machinery, are located within individual photoreceptor cells in two sites in Teleost fish: the pineal organ and retina. In both, light regulates daily variations in melatonin secretion by controlling the activity of arylalkylamine N -acetyltransferase (AANAT). However, in each species examined to date, marked differences exist between the two organs which may involve the genes encoding the photopigments, genes encoding AANAT, the times of day at which AANAT activity and melatonin production peak and the developmental schedule. We review the fish pineal and retinal melatonin rhythm generating systems and consider the evolutional pressures and other factors which led to these differences. [source] Classroom and Developmental Differences in a Path Model of Teacher Expectancy EffectsCHILD DEVELOPMENT, Issue 5 2001Margaret R. Kuklinski A path model of teacher expectancy effects was evaluated in a sample of 376 first- through fifth-grade urban elementary school children. The roles of two moderators (classroom perceived differential treatment environment and developmental differences) and one mediator (children's self-expectations) of teacher expectancy effects on children's year-end achievement were examined. Significant differences in effects and effect sizes are presented. Both classroom environment (high versus low in differential treatment, as seen through children's eyes) and developmental differences moderated the strength of teacher expectancy effects. Generally, stronger effects were found in classrooms in which expectancy-related cues were more salient to children, but developmental differences moderated which effect was most pronounced. A significant age-related decline in direct effects on ending achievement was interpreted as evidence that teacher expectations may tend to magnify achievement differences in the early grades, but serve to sustain them in later grades. Support for indirect effects (teacher expectations , children's self-expectations , ending achievement) was limited to upper elementary grade classrooms perceived as high in differential treatment. In contrast to prior research that emphasized small effect sizes, the present analyses document several instances of moderate effects, primarily in classrooms in which expectancy-related messages were most salient to children. These results underscore the importance of explicit attention to the inclusion of moderators, mediators, and multiple outcomes in efforts to understand teacher expectancy effects. [source] Developmental Differences in Visual and Auditory Processing of Complex SentencesCHILD DEVELOPMENT, Issue 4 2000James R. Booth Children aged 8 through 11 (N= 250) were given a word-by-word sentence task in both the visual and auditory modes. The sentences included an object relative clause, a subject relative clause, or a conjoined verb phrase. Each sentence was followed by a true,false question, testing the subject of either the first or second verb. Participants were also given two memory span measures: digit span and reading span. High digit span children slowed down more at the transition from the main to the relative clause than did the low digit span children. The findings suggest the presence of a U-shaped learning pattern for on-line processing of restrictive relative clauses. Off-line accuracy scores showed different patterns for good comprehenders and poor comprehenders. Poor comprehenders answered the second verb questions at levels that were consistently below chance. Their answers were based on an incorrect local attachment strategy that treated the second noun as the subject of the second verb. For example, they often answered yes to the question ,The girl chases the policeman' after the object relative sentence ,The boy that the girl sees chases the policeman.' Interestingly, low memory span poor comprehenders used the local attachment strategy less consistently than high memory span poor comprehenders, and all poor comprehenders used this strategy less consistently for harder than for easier sentences. [source] Cerebellar granule cells show age-dependent migratory differences in vitroDEVELOPMENTAL NEUROBIOLOGY, Issue 2 2005Krisztián Tárnok Abstract Developmental differences between cerebellar granule cells during their migratory period were revealed using dissociated granule cell cultures isolated from 4, 7, or 10 days old (P4, P7, P10) mice. Under all culture conditions, the great majority of cultivated cell populations consisted of those granule cells that had not reach their final destination in the internal granule cell layer (IGL) by the age of isolation. In vitro morphological development and the expression of migratory markers (TAG-1, astrotactin, or EphB2) showed similar characteristics between the cultures. The migration of 1008 granule cells isolated from P4, P7, and P10 cerebella and cultivated under identical conditions were analyzed using statistical methods. In vitro time-lapse videomicroscopy revealed that P4 cells possessed the fastest migratory speed while P10 granule cells retained their migratory activity for the longest time in culture. Cultures obtained from younger postnatal ages showed more random migratory trajectories than P10 cultures. Our observations indicate that despite similar morphological and molecular properties, migratory differences exist in granule cell cultures isolated from different postnatal ages. Therefore, the age of investigation can substantially influence experimental results on the regulation of cell migration. © 2005 Wiley Periodicals, Inc. J Neurobiol, 2005 [source] Microevolutionary analysis of the nematode genus Pristionchus suggests a recent evolution of redundant developmental mechanisms during vulva formationEVOLUTION AND DEVELOPMENT, Issue 4 2001Jagan Srinivasan SUMMARY To identify the mechanisms by which molecular variation is introduced into developmental systems, microevolutionary approaches to evolutionary developmental biology have to be taken. Here, we describe the molecular and developmental characterization of laboratory strains of the nematode genus Pristionchus, which lays a foundation for a microevolutionary analysis of vulva development. We describe 13 laboratory strains of the Pristionchus genus that are derived from natural isolates from around the world. Mating experiments and ITS sequence analysis indicated that these 13 strains represent four different species: the gonochoristic species P. lheritieri and three hermaphroditic species, P. pacificus, P. maupasi, and an as yet undescribed species Pristionchus sp., respectively. P. pacificus is represented by five different strains isolated from California, Washington, Hawaii, Ontario, and Poland. Developmental differences during vulva formation are observed between strains from different species but also between strains of P. pacificus, like the strains from California and Poland. In particular, redundant developmental mechanisms present during vulva formation in P. pacificus var. California are absent in other strains. Amplified restriction fragment length polymorphism (AFLP) analyses of the P. pacificus strains revealed that the American strains are highly polymorphic. In contrast, the developmentally distinct strain from Poland is identical to the Californian strain, suggesting that the developmental differences rely on a small number of changes in developmental control genes rather than the accumulation of changes at multiple loci. [source] Developmental differences in the immortalization of lung fibroblasts by telomeraseAGING CELL, Issue 5 2003Nicholas R. Forsyth Summary The role of ambient (21%) and physiological oxygen (2,5%) in the immortalization of fetal vs. adult human lung fibroblasts was examined. Growth in low oxygen and antioxidants extended the lifespan of both fetal and adult strains. As the ectopic expression of telomerase could immortalize adult lung fibroblasts cultured in ambient oxygen, the lifespan-shortening effects of 21% oxygen must have been largely limited to telomeres. By contrast, fetal lung fibroblasts could not be immortalized in ambient oxygen in spite of telomere elongation by telomerase, suggesting more widespread oxidative damage. The long-term culture requirements for the immortalization of WI-38 fetal lung fibroblasts included supplementation with N-(tert) butyl hydroxylamine, dexamethasone, zinc and vitamin B12, in addition to growth in physiological oxygen. The mechanisms regulating telomere shortening remain controversial. The present results suggest that both end-replication and oxidative damage events contribute to telomere shortening in lung fibroblasts in vitro. These observations emphasize the need for better analytical techniques to distinguish whether the correlation of short telomeres with disease and mortality in humans reflects the consequences of increased proliferation, telomere shortening as a result of oxidative damage or some combination of these processes. [source] The structure of self-reported problem behaviors in Chinese childrenPSYCHOLOGY IN THE SCHOOLS, Issue 1 2003Tao Xin This study examined the structure of self-reported problem behaviors in Mainland Chinese children. Third grade (n = 3011) and fifth grade (n = 3708) students completed a 20-item Problem Behavior Frequency Checklist (PBFC). Findings suggested that among the four factors studied (physical aggression, substance use, delinquency, and self-centered behaviors), self-centered behaviors and physical aggression were reported most frequently by the Chinese elementary school children. Furthermore, boys had higher prevalence rates of problem behaviors than girls. Developmental differences were also present. Confirmatory factor analyses supported a model that included specific factors related to substance use, physical aggression, delinquency, and self-centered behaviors. Therefore, the single factor conceptualization in which different types of problem behaviors are hypothesized to reflect a single underlying common factor may not hold for this population. © 2003 Wiley Periodicals, Inc. Psychol Schs 40: 19,33, 2003. [source] Brief communication: Dental development and enamel thickness in the Lakonis Neanderthal molarAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 1 2009T.M. Smith Abstract Developmental and structural affinities between modern human and Neanderthal dental remains continue to be a subject of debate as well as their utility for informing assessments of life history and taxonomy. Excavation of the Middle Paleolithic cave site Lakonis in southern Greece has yielded a lower third molar (LKH 1). Here, we detail the crown development and enamel thickness of the distal cusps of the LKH 1 specimen, which has been classified as a Neanderthal based on the presence of an anterior fovea and mid-trigonid crest. Crown formation was determined using standard histological techniques, and enamel thickness was measured from a virtual plane of section. Developmental differences include thinner cuspal enamel and a lower periodicity than modern humans. Crown formation in the LKH 1 hypoconid is estimated to be 2.6,2.7 years, which is shorter than modern human times. The LKH 1 hypoconid also shows a more rapid overall crown extension rate than modern humans. Relative enamel thickness was approximately half that of a modern human sample mean; enamel on the distal cusps of modern human third molars is extremely thick in absolute and relative terms. These findings are consistent with recent studies that demonstrate differences in crown development, tissue proportions, and enamel thickness between Neanderthals and modern humans. Although overlap in some developmental variables may be found, the results of this and other studies suggest that Neanderthal molars formed in shorter periods of time than modern humans, due in part to thinner enamel and faster crown extension rates. Am J Phys Anthropol, 2009. © 2008 Wiley-Liss, Inc. [source] Exploratory behavior in mice selectively bred for developmental differences in aggressive behaviorDEVELOPMENTAL PSYCHOBIOLOGY, Issue 1 2008Kathryn E. Hood Abstract The development and expression of exploratory behavior was assessed in the Cairns lines of Institute for Cancer Research (ICR) mice that were selectively bred for differences in aggressive behavior, with a high-aggressive 900 line, low-aggressive 100 line, and control 500 line. Four paradigms were employed. Developmental changes were evident in the complex novel arena, with older males faster to contact a novel object, and ambulating more than young males. Within the control 500 line, older males showed longer latency to emerge from the home cage, and shorter latency to contact novel objects. In the 900 line, younger males showed this same pattern. R. B. Cairns proposed that line differences in aggressive behavior arise through alterations in developmental timing [Cairns et al. [1983] Life-span developmental psychology (Vol. 5). New York: Academic Press; Gariépy et al. [2001] Animal Behaviour 61: 933,947]. The early appearance of mature patterns of exploratory behavior in 900 line males supports this interpretation. The 900 line males also appear to be behaviorally inhibited in novel settings such as the light,dark box and the neohypophagia paradigm, compared to the 500 and 100 lines (Experiments 1, 2, and 4). Moreover, in the most complex apparatus, the novel arena, 900 line males were slowest to exit the home cage, and fastest to contact a novel object. The apparent contrast in these parameters of exploratory behavior is discussed in relation to T. C. Schneirla's [1965 Advances in the study of behavior (Vol. 1). New York: PN Academic] approach,withdrawal theory. © 2007 Wiley Periodicals, Inc. Dev Psychobiol 50: 32,47, 2008. [source] Seeing the big picture: map use and the development of spatial cognitionDEVELOPMENTAL SCIENCE, Issue 3 2000David H. Uttal This paper considers the relation between the development of spatial cognition and children's use of maps and models. A new theoretical perspective is presented that takes into account the influences of maps on the development of spatial cognition. Maps provide a perspective on spatial information that differs in important ways from the perspective gained from direct experience navigating in the world. Using and thinking about maps may help children to acquire abstract concepts of space and the ability to think systematically about spatial relations that they have not experienced directly. In addition, exposure to maps may help children to think about multiple spatial relations among multiple locations. The results of previous studies that have demonstrated developmental differences in children's cognition of large-scale environments are examined from this theoretical perspective. This review suggests that the development of spatial cognition consists partly of the acquisition of models of large-scale space, and that maps influence the development of the modern Western model. [source] Developmental changes in the BDNF-induced modulation of inhibitory synaptic transmission in the Kölliker,Fuse nucleus of ratEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 12 2007Miriam Kron Abstract The Kölliker,Fuse nucleus (KF), part of the pontine respiratory group, is involved in the control of respiratory phase duration, and receives both excitatory and inhibitory afferent input from various other brain regions. There is evidence for developmental changes in the modulation of excitatory inputs to the KF by the neurotrophin brain-derived neurotrophic factor (BDNF). In the present study we investigated if BDNF exerts developmental effects on inhibitory synaptic transmission in the KF. Recordings of inhibitory postsynaptic currents (IPSCs) in KF neurons in a pontine slice preparation revealed general developmental changes. Recording of spontaneous and evoked IPSCs (sIPSCs, eIPSCS) revealed that neonatally the ,-aminobutyric acid (GABA)ergic fraction of IPSCs was predominant, while in later developmental stages glycinergic neurotransmission significantly increased. Bath-application of BDNF significantly reduced sIPSC frequency in all developmental stages, while BDNF-mediated modulation on eIPSCs showed developmental differences. The eIPSCs mean amplitude was uniformly and significantly reduced following BDNF application only in neurons from rats younger than postnatal day 10. At later postnatal stages the response pattern became heterogeneous, and both augmentations and reductions of eIPSC amplitudes occurred. All BDNF effects on eIPSCs and sIPSCs were reversed with the tyrosine kinase receptor-B inhibitor K252a. We conclude that developmental changes in inhibitory neurotransmission, including the BDNF-mediated modulation of eIPSCs, relate to the postnatal maturation of the KF. The changes in BDNF-mediated modulation of IPSCs in the KF may have strong implications for developmental changes in synaptic plasticity and the adaptation of the breathing pattern to afferent inputs. [source] Microevolutionary analysis of the nematode genus Pristionchus suggests a recent evolution of redundant developmental mechanisms during vulva formationEVOLUTION AND DEVELOPMENT, Issue 4 2001Jagan Srinivasan SUMMARY To identify the mechanisms by which molecular variation is introduced into developmental systems, microevolutionary approaches to evolutionary developmental biology have to be taken. Here, we describe the molecular and developmental characterization of laboratory strains of the nematode genus Pristionchus, which lays a foundation for a microevolutionary analysis of vulva development. We describe 13 laboratory strains of the Pristionchus genus that are derived from natural isolates from around the world. Mating experiments and ITS sequence analysis indicated that these 13 strains represent four different species: the gonochoristic species P. lheritieri and three hermaphroditic species, P. pacificus, P. maupasi, and an as yet undescribed species Pristionchus sp., respectively. P. pacificus is represented by five different strains isolated from California, Washington, Hawaii, Ontario, and Poland. Developmental differences during vulva formation are observed between strains from different species but also between strains of P. pacificus, like the strains from California and Poland. In particular, redundant developmental mechanisms present during vulva formation in P. pacificus var. California are absent in other strains. Amplified restriction fragment length polymorphism (AFLP) analyses of the P. pacificus strains revealed that the American strains are highly polymorphic. In contrast, the developmentally distinct strain from Poland is identical to the Californian strain, suggesting that the developmental differences rely on a small number of changes in developmental control genes rather than the accumulation of changes at multiple loci. [source] Comparative development of fiber in wild and cultivated cottonEVOLUTION AND DEVELOPMENT, Issue 1 2001Wendy L. Applequist SUMMARY One of the most striking examples of plant hairs is the single-celled epidermal seed trichome of cultivated cotton. The developmental morphology of these commercial "fibers" has been well-characterized in Gossypium hirsutum, but little is known about the pattern and tempo of fiber development in wild Gossypium species, all of which have short, agronomically inferior fiber. To identify developmental differences that account for variation in fiber length, and to place these differences in a phylogenetic context, we conducted SEM studies of ovules at and near the time of flowering, and generated growth curves for cultivated and wild diploid and tetraploid species. Trichome initiation was found to be similar in all taxa, with few notable differences in trichome density or early growth. Developmental profiles of the fibers of most wild species are similar, with fiber elongation terminating at about two weeks post-anthesis. In contrast, growth is extended to three weeks in the A- and F-genome diploids. This prolonged elongation period is diagnosed as a key evolutionary event in the origin of long fiber. A second evolutionary innovation is that absolute growth rate is higher in species with long fibers. Domestication of species is associated with a further prolongation of elongation at both the diploid and allopolyploid levels, suggesting the effects of parallel artificial selection. Comparative analysis of fiber growth curves lends developmental support to previous quantitative genetic suggestions that genes for fiber "improvement" in tetraploid cotton were contributed by the agronomically inferior D-genome diploid parent. [source] Intellectual abilities and white matter microstructure in development: A diffusion tensor imaging studyHUMAN BRAIN MAPPING, Issue 10 2010Christian K. Tamnes Abstract Higher-order cognitive functions are supported by distributed networks of multiple interconnected cortical and subcortical regions. Efficient cognitive processing depends on fast communication between these regions, so the integrity of the connections between them is of great importance. It is known that white matter (WM) development is a slow process, continuing into adulthood. While the significance of cortical maturation for intellectual development is described, less is known about the relationships between cognitive functions and maturation of WM connectivity. In this cross-sectional study, we investigated the associations between intellectual abilities and development of diffusion tensor imaging (DTI) derived measures of WM microstructure in 168 right-handed participants aged 8,30 years. Independently of age and sex, both verbal and performance abilities were positively related to fractional anisotropy (FA) and negatively related to mean diffusivity (MD) and radial diffusivity (RD), predominantly in the left hemisphere. Further, verbal, but not performance abilities, were associated with developmental differences in DTI indices in widespread regions in both hemispheres. Regional analyses showed relations with both FA and RD bilaterally in the anterior thalamic radiation and the cortico-spinal tract and in the right superior longitudinal fasciculus. In these regions, our results suggest that participants with high verbal abilities may show accelerated WM development in late childhood and a subsequent earlier developmental plateau, in contrast to a steadier and prolonged development in participants with average verbal abilities. Longitudinal data are needed to validate these interpretations. The results provide insight into the neurobiological underpinnings of intellectual development. Hum Brain Mapp, 2010. © 2010 Wiley-Liss, Inc. [source] 3D Mapping of brain differences in native signing congenitally and prelingually deaf subjectsHUMAN BRAIN MAPPING, Issue 7 2010Natasha Leporé Abstract In the prelingual and congenital deaf, functional reorganization is known to occur throughout brain regions normally associated with hearing. However, the anatomical correlates of these changes are not yet well understood. Here, we perform the first tensor-based morphometric analysis of voxel-wise volumetric differences in native signing prelingual and congenitally deaf subjects when compared with hearing controls. We obtained T1-weighted scans for 14 native signing prelingual and congenitally deaf subjects and 16 age- and gender-matched controls. We used linear and fluid registration to align each image to a common template. Using the voxel-wise determinant of the Jacobian of the fluid deformation, significant volume increases, of up to 20%, were found in frontal lobe white matter regions including Broca's area, and adjacent regions involved in motor control and language production. A similar analysis was performed on hand-traced corpora callosa. A strong trend for group differences was found in the area of the splenium considered to carry fibers connecting the temporal (and occipital) lobes. These anatomical differences may reflect experience-mediated developmental differences in myelination and cortical maturation associated with prolonged monomodal sensory deprivation. Hum Brain Mapp, 2010. © 2009 Wiley-Liss, Inc. [source] Brain network dynamics during error commissionHUMAN BRAIN MAPPING, Issue 1 2009Michael C. Stevens Abstract Previous studies suggest that the anterior cingulate and other prefrontal brain regions might form a functionally-integrated error detection network in the human brain. This study examined whole brain functional connectivity to both correct and incorrect button presses using independent component analysis (ICA) of functional magnetic resonance imaging (fMRI) data collected from 25 adolescent and 25 adult healthy participants (ages 11,37) performing a visual Go/No-Go task. Correct responses engaged a network comprising left lateral prefrontal cortex, left postcentral gyrus/inferior parietal lobule, striatum, and left cerebellum. In contrast, a similar network was uniquely engaged during errors, but this network was not integrated with activity in regions believed to be engaged for higher-order cognitive control over behavior. A medial/dorsolateral prefrontal-parietal neural network responded to all No-Go stimuli, but with significantly greater activity to errors. ICA analyses also identified a third error-related circuit comprised of anterior temporal lobe, limbic, and pregenual cingulate cortices, possibly representing an affective response to errors. There were developmental differences in error-processing activity within many of these neural circuits, typically reflecting greater hemodynamic activation in adults. These findings characterize the spatial structure of neural networks underlying error commission and identify neurobiological differences between adolescents and adults. Hum Brain Mapp 2009. © 2007 Wiley-Liss, Inc. [source] Families, Not Parents, Differ: Development of Communication in Finnish InfantsINFANCY, Issue 2 2009Maija Haapakoski This longitudinal study on Finnish families was conducted to identify developmental differences in family-level communication among mothers, fathers, and their infants during the second half of the infant's first year, and associations with infants' later language and communicative skills. We examined coregulated communication of parent-infant dyads during 5-min laboratory play sessions at 7 and 11 months. Few differences in mutually regulated communicative exchanges emerged between maternal and paternal dyads, and few developmental changes were found across the whole sample. Families with different communication profiles were identified, and changes rather than stability characterized communicative development at the family level. The family-level differences at 7 months predicted variation in children's language and communicative skills at 14 months. [source] Speed of Processing and Face Recognition at 7 and 12 MonthsINFANCY, Issue 4 2002Susan A. Rose This research examined developmental and individual differences in infants' speed of processing faces and the relation of processing speed to the type of information encoded. To gauge processing speed, 7- and 12-month-olds were repeatedly presented with the same face (frontal view), each time paired with a new one, until they showed a consistent preference for the new one. Subsequent probe trials assessed recognition of targets that either preserved configural integrity (Study 1: 3/4 profile and full profile poses) or disrupted it while preserving featural information (Study 2: rotations of 160° or 200° and fracturings). There were developmental differences in both speed and in infants' appreciation of information about faces. Older infants took about 60% fewer trials to reach criterion and had more mature patterns of attention (i.e., looks of shorter duration and more shifts of gaze). Whereas infants of both ages recognized the familiar face in a 3/4 pose, the 12-month-olds also recognized it in profile and when rotated. Twelve-month-olds who were fast processors additionally recognized the fractured faces; otherwise, processing speed was unrelated to the type of information extracted. At 7 months then, infants made use of some configural information in processing faces; at 12 months, they made use of even more of the configural information, along with part-based or featural information. [source] Anorexia nervosa treatment: A systematic review of randomized controlled trials,INTERNATIONAL JOURNAL OF EATING DISORDERS, Issue 4 2007Cynthia M. Bulik PhD Abstract Objective: The RTI International-University of North Carolina at Chapel Hill Evidence-based Practice Center (RTI-UNC EPC) systematically reviewed evidence on efficacy of treatment for anorexia nervosa (AN), harms associated with treatments, factors associated with treatment efficacy, and differential outcome by sociodemographic characteristics. Method: We searched six major databases for studies on the treatment of AN from 1980 to September 2005, in all languages against a priori inclusion/exclusion criteria focusing on eating, psychiatric or psychological, or biomarker outcomes. Results: Thirty-two treatment studies involved only medications, only behavioral interventions, and medication plus behavioral interventions for adults or adolescents. The literature on medication treatments and behavioral treatments for adults with AN is sparse and inconclusive. Cognitive behavioral therapy may reduce relapse risk for adults with AN after weight restoration, although its efficacy in the underweight state remains unknown. Variants of family therapy are efficacious in adolescents, but not in adults. Conclusion: Evidence for AN treatment is weak; evidence for treatment-related harms and factors associated with efficacy of treatment are weak; and evidence for differential outcome by sociodemographic factors is nonexistent. Attention to sample size and statistical power, standardization of outcome measures, retention of patients in clinical trials, and developmental differences in treatment appropriateness and outcome is required. © 2007 by Wiley Periodicals, Inc. Int J Eat Disord 2007 [source] Seasonal, sexual and developmental differences in hoopoe Upupa epops preen gland morphology and secretions: evidence for a role of bacteriaJOURNAL OF AVIAN BIOLOGY, Issue 2 2009Manuel Martín-Vivaldi The uropygial glands of birds serve multiple functions, and there is great interspecific variability in the composition and properties of their secretions. A special case is the secretion in the hoopoes Upupa epops, and green woodhoopoes Phoeniculus purpureus, which, contrary to the commonly white and odourless secretions, are dark with pungent odour. Recently, bacteria have been isolated from glands of both woodhoopoes and hoopoes and here we test the hypothesis that bacteria are responsible of some of the special properties of glands and secretions of this group of birds. We explore natural seasonal changes and intersexual differences in the properties of hoopoe glands and secretions, check the natural occurrence of bacteria within secretions, and analyse the effect of experimental injection of antibiotics on uropygial gland properties. Male glands underwent no seasonal changes, and their secretions were invariably white and odourless, very similar to female glands outside the breeding season. However, in comparison to the uropygial gland of non-breeding females, those of incubating females showed a marked increase in size and volume of secretion produced, which became dark and pungent. All these parameters increased until the hatching date and returned to values similar to those in the prelaying phase towards the end of the nestling period. Nestling glands produced secretions similar to those of females in colour and odour. Gland size of both females and nestlings predicted the amount of secretion produced. Microscopic techniques confirmed the presence of bacteria at high density and in active division in all dark secretions examined. The antibiotic treatment significantly reduced the load of enterococci in nestling glands, did not affect size of glands, but diminished the volume of secretion, which was lighter in colour than that of control nestlings. In nesting females, the experimental injection of antibiotic affected some measurements of gland size and secretion colour. Because the experiment did not affect general health estimates (immunocompetence, body condition or growing) of nestlings, our results suggest that some of the special properties of hoopoe glands are mediated by the presence of symbiotic bacteria. [source] A Rasch Model Analysis of Alcohol Consumption and Problems Across Adolescence and Young AdulthoodALCOHOLISM, Issue 4 2009Christopher W. Kahler Background:, Recent investigations using item response modeling have begun to conceptualize alcohol consumption, problems, and dependence as representing points along a single continuum of alcohol involvement. Such a conceptualization may be of particular benefit to measurement of alcohol involvement in adolescents, but investigations to date have been limited to adult samples and may not generalize to adolescents due to age-related developmental differences. Methods:, This study used Rasch model analyses to examine the properties of indices of alcohol consumption and problems among 6,353 adolescents, aged 12 to 18 years, in Wave 1 of the Add Health survey. A particular focus was on whether the functioning of items changed when these adolescents were re-interviewed in Wave 3 when they were 18 to 24 years of age. Results:, Rasch model analyses supported the unidimensionality and additive properties of the items in the Wave 1 data. Comparisons of Wave 1 and Wave 3 data indicated differential item functioning in most of the items such that items related to alcohol consumption were more severe during adolescence, whereas items related to alcohol problems were more severe in young adulthood. Conclusions:, A valid index of alcohol involvement in adolescents can be constructed combining indices of alcohol consumption and alcohol problems. Such an index covers a range of severity and functions similarly across sex and race/ethnicity. A similar index can be constructed in young adulthood. However, the interpretation of scores must be attentive to developmental differences. In particular, for adolescents, indices of alcohol consumption are relatively closer in severity to indices of alcohol problems than they are among young adults. Thus, alcohol problems are more likely among adolescents than young adults given a similar level of drinking. [source] Toward a predictive model of patient satisfaction with nurse practitioner careJOURNAL OF THE AMERICAN ACADEMY OF NURSE PRACTITIONERS, Issue 4 2005A/G/FNP, Ann Green PhD Purpose (a) To determine if caring behaviors of nurse practitioners (NPs), gender of NPs, setting (urban or rural), and age, gender, ethnicity, education, and income of patients were predictors of patient satisfaction; (b) to determine which of these characteristics was the best predictor(s) of patient satisfaction; and (c) begin to develop a conceptual model for explaining patient satisfaction with NP care. Data sources Responses to the Caring Behaviors Inventory (CBI) and a demographic inquiry by 348 NPs in Louisiana and completion of the Di'Tomasso,Willard Patient Satisfaction Questionnaire (DWPSQ) and a demographic inquiry from 817 patients in Louisiana served as data sources. A predictive modeling design explored which variable(s) is the best predictor of patient satisfaction, and multiple regression was used to determine the equation for the best-fitting line and the optimal model for the best predictor(s) of patient satisfaction. Conclusions CBI mean scores were high for all NPs. No statistically significant difference was found between male NPs' and female NPs' total mean CBI scores and between urban or rural total mean CBI scores. DWPSQ mean scores and subscale scores indicated high satisfaction with NP care. No statistically significant relationships were found between the NPs' CBI mean scores and the patients' DWPSQ mean scores. There were significant relationships between the DWPSQ subscales, including Wait Time and Patient Management. Stepwise linear regression revealed that patients' age group was a predictor of DWPSQ total mean scores. Implications for practice NPs need to be aware of developmental differences in all age groups and the differences in perceptions of care. There are many variables to consider when determining patient satisfaction with care, including the patients' sociodemographic and health variables, the healthcare system, and characteristics of the healthcare providers. Awareness of these variables may affect how NPs deliver care and ensure quality care with which the patients are satisfied. [source] Growth in Precursor and Reading-Related Skills: Do Low-Achieving and IQ-Discrepant Readers Develop Differently?LEARNING DISABILITIES RESEARCH & PRACTICE, Issue 1 2002Kimberly J. O'Malley Poor readers who met low achievement and IQ-discrepancy definitions of reading disability were compared with nonimpaired readers on their development of eight precursor and reading-related skills to evaluate developmental differences prior to students' identification as reading disabled. Results indicated no evidence for differences between the two groups of poor readers in the development of the eight skills, with three exceptions. Students in the IQ-discrepant group demonstrated greater growth in letter sound knowledge, greater mean performance in visual-motor integration at the beginning of first grade, and greater deceleration in rapid naming of letters. When compared to the nonimpaired group, low-achieving readers demonstrated poorer performance and development in all skills, while the IQ-discrepant readers demonstrated poorer performance and development in phonemic awareness, rapid naming of letters and objects, spelling, and word reading. The largely null results for comparisons between the two groups of poor readers challenges the validity of the two-group classification of reading disabilities based on IQ-discrepancy. [source] Examining developmental differences in the social-emotional problems among frequent bullies, victims, and bully/victims,PSYCHOLOGY IN THE SCHOOLS, Issue 2 2009Lindsey M. O'Brennan Bullying poses a threat to children's social-emotional functioning and their perceptions of school climate, yet few studies have examined different types of social-emotional and behavior problems presented by children involved in bullying, as a bully, victim, or bully/victim across multiple school levels. The current study used data from 24,345 elementary-, middle-, and high-school students to examine the association between frequent involvement in bullying and aggressive impulsivity, attitudes toward aggressive retaliation, internalizing symptoms, peer relations, and perceptions of school climate. Logistic regression analyses indicated that bully/victims were most likely to display internalizing symptoms, problems in peer relationships, and have poorer perceptions of the school environment. Both frequent bullies and bully/victims displayed aggressive-impulsive behavior and endorsed retaliatory attitudes. High-school students frequently involved in bullying tended to display the greatest risk for internalizing problems, but less risk for aggressive impulsivity. Developmental trends and implications for prevention and early intervention are discussed. © 2008 Wiley Periodicals, Inc. [source] Asymmetric allele-specific expression in relation to developmental variation and drought stress in barley hybridsTHE PLANT JOURNAL, Issue 1 2009Maria Von Korff Summary In the present study, we analysed allele-specific expression (ASE) in the selfing species barley to assess the frequency of cis -acting regulatory variation and the effects of genetic background, developmental differences and drought stress on allelic expression levels. We measured ASE ratios in 30 genes putatively involved in stress responses in five hybrids and their reciprocals, namely Hordeum spontaneum 41-1/Alexis (HAl), Hordeum spontaneum 41-1/Arta (HAr), Sloop/WI3408 (SW), Tadmor/Sloop (TS) and Tadmor/WI3408 (TW). In order to detect cis -acting variation related to drought and developmental changes, the barley hybrids were grown under control and water-limited conditions, and leaf tissue was harvested at two developmental stages. The analysis demonstrated that more than half of the genes measured (63%) showed allelic differences in expression of up to 19-fold due to cis -regulatory variation in at least one cross by treatment/stage combination. Drought stress induced changes in allelic expression ratios, indicating differences between drought responsive cis -elements. In addition, ASE differences between developmental stages suggested the presence of cis -acting elements interacting with developmental cues. We were also able to demonstrate that the levels and frequency of allelic imbalance and hence differences in cis -regulatory elements are correlated with the genetic divergence between the parental lines, but may also arise as an adaptation to diverse habitats. Our findings suggest that cis -regulatory variation is a common phenomenon in barley, and may provide a molecular basis of transgression. Differential expression of near-isogenic members of the same gene family could potentially result in hybrid lines out performing their parents in terms of expression level, timing and response to developmental and environmental cues. Identification and targeted manipulation of cis -regulatory elements will assist in breeding improved crops with a better adaptation to changing environments. [source] Cognitive and social effects in allocation behavior: A new view on loci of developmental differencesASIAN JOURNAL OF SOCIAL PSYCHOLOGY, Issue 1 2002Ramadhar Singh Allocations become more equitable with age in America but not in Asia. The authors hypothesized that age affects perception of inputs but a combination of perceived inputs and social value determines allocation behavior. The subtractive model guided data gathering from Chinese in Singapore. Experiment 1 confirmed the Asian age-trend, and demonstrated age differences in perceived inputs. Rated importance of perceived inputs decreased but that of group harmony increased from 5 to 17 years. In Experiment 2, the relationship between perception of ,fair' shares driven by perceived inputs and pay allocations by 11,15-year-olds was non-linear, showing considerable adjustments in allocation behavior. In Experiment 3, allocation behaviors and perceived inputs of 5,21-year-olds had the Asian and American age-trends, respectively. Obviously, allocation behavior in Asia is a compromise between the conflicting prescriptions of cognitive and social development. [source] Minimal aberrant behavioral phenotypes of neuroligin-3 R451C knockin miceAUTISM RESEARCH, Issue 3 2008Kathryn K. Chadman Abstract Neuroligin-3 is a member of the class of cell adhesion proteins that mediate synapse development and have been implicated in autism. Mice with the human R451C mutation (NL3), identical to the point mutation found in two brothers with autism spectrum disorders, were generated and phenotyped in multiple behavioral assays with face validity to the diagnostic symptoms of autism. No differences between NL3 and their wildtype (WT) littermate controls were detected on measures of juvenile reciprocal social interaction, adult social approach, cognitive abilities, and resistance to change in a spatial habit, findings which were replicated in several cohorts of males and females. Physical and procedural abilities were similar across genotypes on measures of general health, sensory abilities, sensorimotor gating, motor functions, and anxiety-related traits. Minor developmental differences were detected between NL3 and WT, including slightly different rates of somatic growth, slower righting reflexes at postnatal days 2,6, faster homing reflexes in females, and less vocalizations on postnatal day 8 in males. Significant differences in NL3 adults included somewhat longer latencies to fall from the rotarod, less vertical activity in the open field, and less acoustic startle to high decibel tones. The humanized R451C mutation in mice did not result in apparent autism-like phenotypes, but produced detectable functional consequences that may be interpreted in terms of physical development and/or reduced sensitivity to stimuli. [source] Classroom and Developmental Differences in a Path Model of Teacher Expectancy EffectsCHILD DEVELOPMENT, Issue 5 2001Margaret R. Kuklinski A path model of teacher expectancy effects was evaluated in a sample of 376 first- through fifth-grade urban elementary school children. The roles of two moderators (classroom perceived differential treatment environment and developmental differences) and one mediator (children's self-expectations) of teacher expectancy effects on children's year-end achievement were examined. Significant differences in effects and effect sizes are presented. Both classroom environment (high versus low in differential treatment, as seen through children's eyes) and developmental differences moderated the strength of teacher expectancy effects. Generally, stronger effects were found in classrooms in which expectancy-related cues were more salient to children, but developmental differences moderated which effect was most pronounced. A significant age-related decline in direct effects on ending achievement was interpreted as evidence that teacher expectations may tend to magnify achievement differences in the early grades, but serve to sustain them in later grades. Support for indirect effects (teacher expectations , children's self-expectations , ending achievement) was limited to upper elementary grade classrooms perceived as high in differential treatment. In contrast to prior research that emphasized small effect sizes, the present analyses document several instances of moderate effects, primarily in classrooms in which expectancy-related messages were most salient to children. These results underscore the importance of explicit attention to the inclusion of moderators, mediators, and multiple outcomes in efforts to understand teacher expectancy effects. [source] Human embryo and early fetus researchCLINICAL GENETICS, Issue 2 2006H Ostrer Studies of human embryos and fetuses have highlighted developmental differences between humans and model organisms. In addition to describing the normal biology of our own species, a justification in itself, studies of early human development have aided identification of candidate disease genes mapped by positional cloning strategies, understanding pathophysiology, where human disorders are not faithfully reproduced by models in other species, and, more recently, potential therapies based on human embryonic stem and embryonic germ cells. In this article, we review these applications. We also discuss when and how to study human embryo and early fetuses and some of the regulations of this research. [source] | |||||||||||||||||||