Perceived social support in a large community sample - Age and sex differences

Background. The positive health and wellbeing effects of social support have been consistently demonstrated in the literature since the late 1970s. However, a better understanding of the effects of age and sex is required. Method. We examined the factor structure and reliability of Kessler's Perceived Social Support (KPSS) measure in a community-based sample that comprised younger and older adult cohorts from the Australian Twin Registry (ATR), totalling 11,389 males and females aged 18-95, of whom 887 were retested 25 months later. Results. Factor analysis consistently identified seven factors: support from spouse, twin, children, parents, relatives, friends and helping support. Internal reliability for the seven dimensions ranged from 0.87 to 0.71 and test-retest reliability ranged from 0.75 to 0.48. Perceived support was only marginally higher in females. Age dependencies were explored. Across the age range, there was a slight decline (more marked in females) in the perceived support from spouse, parent and friend, a slight increase in perceived relative and helping support for males but none for females, a substantial increase in the perceived support from children for males and females and a negligible decline in total KPSS for females against a negligible increase for males. The perceived support from twin remained constant. Females were more likely to have a confidant, although this declined with age whilst increasing with age for males. Conclusions. Total scores for perceived social support conflate heterogeneous patterns on sub-scales that differ markedly by age and sex. Our paper describes these relationships in detail in a very large Australian sample.

The epidemiology and genetics of smoking initiation and persistence: Crosscultural comparisons of twin study results

We examined whether there are crosscultural differences in the magnitude of genetic and environmental contributions to risk of becoming a regular smoker and of persistence in smoking in men and women. Standard methods of epidemiologic and genetic analysis were applied to questionnaire data on history of cigarette use obtained from large samples of male and female like-sex twins from three different countries: Australia (N = 2284 pairs), Sweden (N = 8651 pairs), and Finland (N = 10,948 pairs). Samples were subdivided into three age groups (AG), 18-25 years, 26-35 years, and 36-46 years of age. The magnitude of genetic influence for lifetime smoking was found to be consistent across country and AG for women (46%) and men (57%), and estimates of the contribution from environmental influences shared by twin and co-twin could be equated across all countries by AG for the women (from youngest to oldest AG: 45%, 35%, and 26%), but not for men, with separate estimates obtained for the Scandinavian (33%, 29%, and 19%) and the Australian men (26%, 9%, and 11 %). There was no evidence for an important role for shared environmental influences on persistent smoking, and the genetic contribution was found to be consistent in magnitude in men and women, and the same across country and AG (52%). There are strong genetic influences on smoking behavior, and that risk of becoming a smoker (but not persistence in smoking) may be modified by experiences shared by twins that differ by AG and, at least for men, cultural background.

Molecular structure and function of the glycine receptor chloride channel

The glycine receptor chloride channel (GlyR) is a member of the nicotinic acetylcholine receptor family of ligand-gated ion channels. Functional receptors of this family comprise five subunits and are important targets for neuroactive drugs. The GlyR is best known for mediating inhibitory neurotransmission in the spinal cord and brain stem, although recent evidence suggests it may also have other physiological roles, including excitatory neurotransmission in embryonic neurons. To date, four alpha-subunits (alpha1 to alpha4) and one beta-subunit have been identified. The differential expression of subunits underlies a diversity in GlyR pharmacology. A developmental switch from alpha2 to alpha1beta is completed by around postnatal day 20 in the rat. The beta-subunit is responsible for anchoring GlyRs to the subsynaptic cytoskeleton via the cytoplasmic protein gephyrin. The last few years have seen a surge in interest in these receptors. Consequently, a wealth of information has recently emerged concerning Glyl? molecular structure and function. Most of the information has been obtained from homomeric alpha1 GlyRs, with the roles of the other subunits receiving relatively little attention. Heritable mutations to human GlyR genes give rise to a rare neurological disorder, hyperekplexia (or startle disease). Similar syndromes also occur in other species. A rapidly growing list of compounds has been shown to exert potent modulatory effects on this receptor. Since GlyRs are involved in motor reflex circuits of the spinal cord and provide inhibitory synapses onto pain sensory neurons, these agents may provide lead compounds for the development of muscle relaxant and peripheral analgesic drugs.

Does industry matter? Examining the role of industry structure and organizational learning in innovation and brand performance

A manager's perception of industry structure (dynamism) has the potential to impact various organizational strategies and behaviors. This may be particularly so with regard to perceptions driving organizational learning orientations and innovation based marketing strategy. The position taken here suggests that firms operating within a competitive industry tend to pursue innovative ways of performing value-creating activities, which requires the development of learning capabilities. The results of a study of SMEs suggest that market focused learning, relative to other learning capabilities plays a key role in the relationships between industry structure, innovation and brand performance. The findings also show that market focused learning and internally focused learning influence innovation and that innovation influences a brand's performance. (c) 2005 Elsevier Inc. All rights reserved.

The structure and infrastructure of Mexico's science and technology

The structure and infrastructure of the Mexican technical literature was determined. A representative database of technical articles was extracted from the Science Citation Index for the year 2002, with each article containing at least one author with a Mexican address. Many different manual and statistical clustering methods were used to identify the structure of the technical literature (especially the science and technology core competencies). One of the pervasive technical topics identified from the clustering, thin films research, was analyzed further using bibliometrics, in order to identify the infrastructure of this technology. Published by Elsevier Inc.

Rice morphogenesis and plant architecture: Measurement, specification and the reconstruction of structural development by 3D architectural modelling

Background and Aims The morphogenesis and architecture of a rice plant, Oryza sativa, are critical factors in the yield equation, but they are not well studied because of the lack of appropriate tools for 3D measurement. The architecture of rice plants is characterized by a large number of tillers and leaves. The aims of this study were to specify rice plant architecture and to find appropriate functions to represent the 3D growth across all growth stages. Methods A japonica type rice, 'Namaga', was grown in pots under outdoor conditions. A 3D digitizer was used to measure the rice plant structure at intervals from the young seedling stage to maturity. The L-system formalism was applied to create '3D virtual rice' plants, incorporating models of phenological development and leaf emergence period as a function of temperature and photoperiod, which were used to determine the timing of tiller emergence. Key Results The relationships between the nodal positions and leaf lengths, leaf angles and tiller angles were analysed and used to determine growth functions for the models. The '3D virtual rice' reproduces the structural development of isolated plants and provides a good estimation of the fillering process, and of the accumulation of leaves. Conclusions The results indicated that the '3D virtual rice' has a possibility to demonstrate the differences in the structure and development between cultivars and under different environmental conditions. Future work, necessary to reflect both cultivar and environmental effects on the model performance, and to link with physiological models, is proposed in the discussion.

Isolation, solution structure, and insecticidal activity of Kalata B2, a circular protein with a twist: Do Mobius strips exist in nature?

A large number of macrocyclic miniproteins with diverse biological activities have been isolated from the Rubiaceae, Violaceae, and Cucurbitaceae plant families in recent years. Here we report the three-dimensional structure determined using H-1 NMR spectroscopy and demonstrate potent insecticidal activity for one of these peptides, kalata B2. This peptide is one of the major components of an extract from the leaves of the plant Oldenlandia affinis. The structure consists of a distorted triple-stranded beta-sheet and a cystine knot arrangement of the disulfide bonds and is similar to those described for other members of the cyclotide family. The unique cyclic and knotted nature of these molecules makes them a fascinating example of topologically complex proteins. Examination of the sequences reveals that they can be separated into two subfamilies, one of which contains a larger number of positively charged residues and has a bracelet-like circularization of the backbone. The second subfamily contains a backbone twist due to a cis-peptidyl-proline bond and may conceptually be regarded as a molecular Mobius strip. Kalata B2 is the second putative member of the Mobius cyclotide family to be structurally characterized and has a cis-peptidyl-proline bond, thus validating the suggested name for this subfamily of cyclotides. The observation that kalata B2 inhibits the growth and development of Helicoverpa armigera larvae suggests a role for the cyclotides in plant defense. A comparison of the sequences and structures of kalata B1 and B2 provides insight into the biological activity of these peptides.

Perceptions of the intergroup structure and anti-Asian prejudice among white Australians

Subjective intergroup beliefs and authoritarianism were assessed in a field study (N=255) of White Australians' anti-Asian stereotyping and prejudice. A social identity analysis of intergroup prejudice was adopted, such that perceptions of the intergroup structure (instability, permeability, legitimacy and higher ingroup status) were proposed as predictors of higher prejudice (blatant and covert) and less favorable stereotyping. Consistent with the social identity approach, both independent and interacting roles for sociostructural predictors of Anti-Asian bias were observed, even after demographic and personality variables were controlled. For example, perceived legitimacy was associated with higher prejudice when White Australians' status position relative to Asian Australians was valued. Moreover, when participants evaluated Whites' position as unstable and high status or legitimate, perceptions of permeable intergroup boundaries were associated with anti-Asian bias. The present findings demonstrate status protection responses in advantaged group members in a field setting, lending weight to the contention that perceptions of sociostructural threat interact to predict outgroup derogation. Implications for theories of intergroup relations are discussed.

Post-hatching growth and development of the pectoral and pelvic limbs in the black noddy, Anous minutus

The black tern (Anous minutus) uses a semi-precocial growth strategy. Terrestrial locomotor capacity occurs soon after hatching, but pectoral limb development is delayed and flight is not possible until about post-hatching day 50. A growth series (hatchlings to fledglings) was used to explore how limb musculoskeletal development varied with body mass. In the pelvic limb, bone lengths scaled isometrically or with negative allometry. Gastrocnemius muscle mass and the failure load and stiffness of the tibiotarsus scaled isometrically. In the pectoral limb, pectoralis and supracoracoideus muscle masses increased with strong positive allometry that was mirrored by increases in wing bone strength and stiffness. Bending strength (σult) and modulus (E) remained fairly constant throughout development to fledging for all limb bones. The moment of inertia (I) scaled with negative allometry for the tibiotarsus and with strong positive allometry in the wing bones. Differences in σult and E of the tibiotarsus between pre-fledged chicks and adults was due, primarily, to increases in bone density rather than increases in the moment of inertia of the skeletal elements, whereas σult of wing bones was a function of increases in both bone density and I. Early development of functional pelvic limbs in tree-nesting birds is relatively unusual, and presumably reflects a familial trait that does not appear to compromise breeding success in this species.