Microsatellite variation in the yellowhammer Emberiza citrinella : population structure of a declining farmland bird

In recent years, there has been much concern in the UK about population declines of widespread species in agricultural habitats. Conservation-orientated research on declining birds has focused on vital rates of survival and productivity. However, the environmental factors which may influence movements between populations of widespread species is poorly understood. Population genetic structure is an indirect description of dispersal between groups of individuals. To attempt to develop an understanding of genetic structuring in a widespread, but declining, farmland bird, we therefore investigated the yellowhammer, Emberiza citrinella, population in England and Wales using microsatellite data. Our first aim was to investigate whether there was genetic substructuring in the population. A second aim was to investigate if there was a relationship between genetic distances and various environmental variables. Finally, we analysed the microsatellite data for evidence of loss of genetic variation due to population decline. Our data showed a slight but significant structure within the yellowhammer population. This therefore cannot be considered a panmictic population. Our example from South Cumbria implies that high-altitude barriers may have a slight influence on population structure. However, on the whole, genetic distances between sample sites were not significantly correlated with geographical distances, degrees of population connectivity, high altitudes, or differences in precipitation between sites. Finally, we detected departures from mutation-drift equilibrium (excess heterozygosity), which is indicative of a loss of genetic variation through recent decline.

Hierarchial patterns of invertebrate assemblage structure in stony upland streams change with time and flow permanence

1. Studies in several parts of the world have examined variation in univariate descriptors of macroinvertebrate assemblage structure in perennially flowing stony streams across hierarchies of spatial scale using nested analyses of variance. However, few have investigated whether this spatial variation changes with time or whether these results are representative of habitats other than riffles or of other stream types, such as intermittently flowing streams.

2. We describe patterns in taxon richness and abundance from two sets of samples from stony streams in the Otway Range and the Grampians Range, Victoria, Australia, collected using hierarchical designs. Sampling of riffles was repeated in the Otways, to determine whether spatial patterns were consistent among times. In the Grampians, spatial patterns were compared between intermittent and perennially flowing streams (stream type) by sampling pools.

3. In the Otways streams, most variation in the dependent variables occurred between sample units. Patterns of variation among the other scales (streams, segments, riffles, groups of stones) were not consistent between sampling times, suggesting that they may have little ecological significance.

4. In the Grampians streams, variation in macroinvertebrate taxon richness and abundance differed significantly between replicate streams within each stream type but not between stream types or pools. The largest source of variation in taxon richness was stream type. Little variation occurred among sample units.

5. The pattern of most variation occurring among sample units is robust both to differences in the method of sampling and different dependent variables among studies and increasingly appears to be a property of riffles in stony, perennial upland streams. High variation among sample units (residual variation) limits the explanatory power of linear models and therefore, where samples are from a single sampling time, small but significant components of variation are unlikely to represent features of assemblage structure that will be stable over time.

Family structure and children's television viewing and physical activity

Objectives: This study aimed to examine how physical activity (PA) and television (TV) viewing time of children varied according to family structure.

Methods: In 2001, 5- to 6-yr-old (N = 296) and 10- to 12-yr-old (N = 919) children and their parents were recruited from 19 state elementary schools in Melbourne, Australia. Children's PA was objectively assessed using accelerometers worn for 8 d. Sociodemographic and family structure information and time spent watching TV was collected via questionnaire completed by parents.

Results: ANCOVA revealed that, after controlling for socioeconomic status and age of child, boys without any siblings spent more minutes per day watching TV (153.2 +/- 71.3) compared with those who have siblings (129.0 +/- 64.4, P < 0.05). There were also significant differences in TV viewing time between boys with one sibling (125.5 +/- 59.9), two siblings (141.9 +/- 70.1), or three or more siblings (111.6 +/- 62.6, P < 0.001). Girls from single-parent families (145.7 +/- 85.1) spent significantly more minutes per day watching TV compared with girls from two-parent families (125.1 +/- 67.7, P < 0.05). Girls with siblings spent more minutes per day in PA (148.3 +/- 67.7) compared with those who were an only child (131.0 +/- 58.9, P < 0.05). There were significant interactions between parental status and having a sibling, with PA, and also with TV viewing for girls and between parental status and having a brother with PA for boys. There were also significant interactions between having an older sibling and child's sex with PA and between number of siblings and sex with TV viewing.

Conclusions: Family structure may be an important source of influence on children's PA and TV viewing time. Aspects of family structure interact differently with PA and TV viewing, suggesting interventions may need to be tailored with consideration of the family structure of children.

Effect of fire on Benthic Algal Assemblage structure and recolonisation in intermittent streams

Dry biofilm on rocks and other substrata forms an important drought refuge for benthic algae in intermittent streams following the cessation of flow. This dry biofilm is potentially susceptible to disturbance from bushfires, including direct burning and/or scorching and damage from radiant heat, particularly when streams are dry. Therefore, damage to dry biofilms by fire has the potential to influence algal recolonization and assemblage structure in intermittent streams following commencement of flow. The influence of fire on benthic algal assemblages and recolonization was examined in intermittent streams of the Grampians National Park, Victoria, Australia, using a field survey and manipulative field experiment. The field survey compared assemblages in two intermittent streams within a recently burnt area (within 5 months of the fire) with two intermittent streams within an unburnt area. The two burnt streams were still flowing during the fire so most biofilms were not likely to be directly exposed to flames. Considerable site-to-site and stream-to-stream variation was detected during the field survey, which may have obscured potential differences attributable to indirect effects of the fire. The manipulative field experiment occurred in two intermittent streams and consisted of five treatments chosen to replicate various characteristics of bushfires that may influence dry biofilms: dry biofilm exposed directly to fire; dry biofilm exposed to radiant heat; dry biofilm exposed to ash; and two procedural controls. After exposure to the different treatments, rocks were replaced in the streams and algae were sampled 7 days after flow commenced. Differences occurred across treatments, but treatment differences were inconsistent across the two streams. For example, direct exposure to fire reduced the abundance of recolonizing algae and altered assemblage structure in both streams, while radiant heat had an effect on assemblage structure in one stream only. The manipulative field experiment is likely to have represented the intensity of a small bushfire only. Nonetheless, significant differences across treatments were detected, so these experimental results suggest that fire can damage dry biofilms, and hence, influence algal recolonization and assemblage structure in intermittent streams.

Ultrafine grained structure formation in steels using dynamic strain induced transformation processing

The refinement of ferrite grain size is the most generally accepted approach to simultaneously improve the strength and toughness in steels. Historically, the level of ferrite refinement is limited to 5-10 μm using conventional industrial approaches. Nowadays, though, several thermomechanical processes have been developed to produce ferrite grain sizes of 1-3 μm or less, ranging from extreme thermal and deformation cycles to more typical thermomechanical processes. The present paper reviews the status of the production of ultrafine grained steels through relatively simple thermomechanical processing. This requires deformation within the Ae3 to Ar3 temperature range for a given alloy. Here, the formation of ultrafine ferrite (UFF) involves the dynamic transformation of a significant volume fraction of the austenite to ferrite. This dynamic strain induced transformation (DSIT) arises from the introduction of extensive intragranular nucleation sites that are not present in conventional controlled rolling. The DSIT route has the potential to be adjusted to suit current industrial infrastructure. However, there are a number of significant issues that have been raised, both as gaps in our understanding and as obstacles to industrial implementation. One of the critical issues is that it appears that very large strains are required. Combined with this concern is the issue of whether a combination of dynamic and static transformation can be used to achieve an adequate level of refinement. Another issue that has also become apparent is that grain sizes of 1 μm can lead to low levels of ductility and hence many workers are attempting to obtain 2-3 μm grains, or to introduce a second phase to provide the required ductility. There are also a number of areas of disagreement between authors including the role of dynamic recrystallisation of ferrite in the production of UFF by DSIT, the reasons for the low coarsening rate of UFF grains, the role of microalloying elements and the effects of austenite grain size and strain rate. The present review discusses these areas of controversy and highlights cases where experimental results do not agree.

Influence of social network structure on entrepreneurship participation — a study of 20 national

By investigating differences in social networks among entrepreneurs in 20 cultures, this paper contributes to the debate on whether there is universality in the process of entrepreneurial networking. Representative samples of entrepreneurs were identified in the same manner in 20 countries from 2000 to 2004 (N=€‰304,560). The sampling methodologies and the questions asked were similar across all countries. Logistic regression was used to test for significant regional interaction effects involving personally knowing an entrepreneur. Results are contrary to the existence of any mono-dimensional form of networking practice but do strongly support the existence of both variform universality (culture moderates the importance of networking) and functional universality (cultural similarities in networking practice exist).

The impact of ownership structure on corporate debt policy : two stage least square simultaneous model approach for post crisis period : evidence from Kuala Lumpur Stock Exchange

Ownership concentration as a governance mechanism has received considerable attention among academician, practitioners as well as policy makers because large-block shareholders are increasingly active in their demands that corporations adopt effective governance mechanisms to control managerial decisions, which include corporate debt policy. Earlier study on the agency model of the firm widely recognizes that the managerial ownership and external debt play an important role in mitigating agency conflicts and enhancing firm value. They also found that increase in the external monitors, for example the institutional investors, can actually play a useful role in limiting agency problems in the firm. This paper, using 100 Composite Index companies from Brusa Malaysia between 1998 to 2002 explores the impact of institutional holdings on managerial ownership and debt policy in an integrated framework by using a simultaneous equations estimation procedure (2SLS). The findings show that there is a significant impact of institutional ownership which serves effective control mechanism on managerial ownership and corporate debt policy as hypothesized. Findings of such evidence suggest that institutional holding thus have played an important role in managers' strategic management decision and reduce agency conflict. In addition, corporate debt policy too is governed by managerial ownership and exhibited a negative relation.

Corporate governance structure and firm performance : empirical evidence from Brusa Malaysia, Kuala Lumper

The issue of corporate governance has been emerging as important phenomena that has been searched extensively both in developed countries due to its strategic impact on the monitoring of management activities and firms’ performance. Yet little attempt has been made in developing countries like Malaysia to ascertain what constitute corporate governance and its impact on firm's performance. Therefore, this study aims at examining the structure of the corporate governance and its impact on firm’s performance. This study is based on 100 firms, which are the component of the Composite Index (CI) serve as market barometer. This study employs cross-sectional annual multiple regression model to examine, what constitutes the corporate governance structure and its impact on performance of the firm. The analysis was based on annual regression over 5 years period from 1997 through 2001. Three different blend of surrogate for corporate governance were developed for good corporate governance structure. These are the independent non-executive (outside) directors, audit committee and remuneration committee. To isolate the size effect from the impact of corporate governance structure on firm’s performance, firm’s size was also included are variable in the model. The ratio of net income before tax to total asset is used as a surrogate for firm’s performance. Evidence from the study indicates that there is partial relation between corporate governance structure and corporate performance. The presence of both audit and remuneration committee serves as an important monitoring device to control management activities that lead to increase firm's performance. While on average, the presence of independent nonexecutive directors does not provide any significant explanation for the firm's performance. However, the firm size appears to have significant impact on corporate performance.

The relation between decentralised structure, budgetary participation and organisational commitment : the moderating role of managers' value orientation towards innovation

Reports the results of a study which investigated the moderating role of managers’ value orientation towards innovation (VOI) on the relationships between managers’ organisational commitment and two management control features – decentralised organisational structure and budgetary participation. Data for the study were collected from 116 managers in manufacturing firms. The results indicate that managers’ VOI has a significant moderating effect on the relationships between the two management control features and managers’ organisational commitment. The results reveal that the relationships are stronger for managers with high VOI than for managers with low VOI. These results have implications for enhancing managers’ organisational commitment through the design of management control systems appropriate for the extent of innovative work values promoted by organisations.

Household structure and consumption insurance of the elderly

This paper examines the role of household formation in providing consumption insurance to the elderly. Using data from the Consumer Expenditure Surveys, raw tabulations of per adult equivalent consumption indicate that the elderly who live alone have higher levels of well-being relative to those who live with others. This is misleading, however, because the decision to live alone is clearly endogenous. The empirical estimation accounts for this endogeneity using data from the Panel Study of Income Dynamics. The results provide evidence that household formation plays a significant role in maintaining consumption levels. Without the opportunity to live with others, the welfare gap measured by the difference between per adult equivalent consumption levels of dependent and independent livers would be even larger. These findings suggest that co-residing with others effectively supplements social security, pensions, and private savings and helps the elderly to smooth consumption in old age.

Sources of liquidity commonality, asymmetric information and ownership structure in emerging markets : evidence from the Chinese stock market

Xinwei Zheng examines if common factors of liquidity can be determined by ownership structure measured by asymmetric information in an emerging market that has adopted an order-driven trading system. Using China as a case for the study, I select a broad sample of stocks from two separate Chinese stock exchanges to measure and
analyse the relationship. My empirical evidence seems significant and pervasive. These findings about the Chinese stock market provide useful pointers for understanding commonality in emerging economies and shed critical light
on a new dimension of the working of emerging markets.

Dots versus antidots : computational exploration of structure, magnetism, and half-metallicity in boron-nitride nanostructures

Triangle-shaped nanohole, nanodot, and lattice antidot structures in hexagonal boron-nitride (h-BN) monolayer sheets are characterized with density functional theory calculations utilizing the local spin density approximation. We find that such structures may exhibit very large magnetic moments and associated spin splitting. N-terminated nanodots and antidots show strong spin anisotropy around the Fermi level, that is, half-metallicity. While B-terminated nanodots are shown to lack magnetism due to edge reconstruction, B-terminated nanoholes can retain magnetic character due to the enhanced structural stability of the surrounding two-dimensional matrix. In spite of significant lattice contraction due to the presence of multiple holes, antidot super lattices are predicted to be stable, exhibiting amplified magnetism as well as greatly enhanced half-metallicity. Collectively, the results indicate new opportunities for designing h-BN-based nanoscale devices with potential applications in the areas of spintronics, light emission, and photocatalysis. © 2009 American Chemical Society.

Who will be an entrepreneur? How cultural mechanisms and social network structure together influence entrepreneurial participation

Using data collected from 35 countries over five years, this study provides an investigation of the combined influence of cultural factors and social network structure on whether or not an individual, anywhere in the world, becomes an entrepreneur. Results show that knowing someone who has started a business recently, across the world, has a significant impact on entrepreneurship participation. Regarding the potential cultural influences, it seems that importance attached to personally knowing entrepreneurs differs significantly between individuals operating in different cultures. In cultures with high power distance, personally knowing a person who recently started a business is relatively less important as a driver of entrepreneurship participation compared to cultures with low power distance. On the other hand, in cultures where the Hofstede’s ‘masculinity’construct predominates, it is more important than in cultures characterised by ‘femininity’.

The effect of nano-particle TiO2 fillers on structure and transport in polymer electrolytes

Nano-particle oxide fillers including TiO₂, SiO₂ and Al₂O₃ have previously been shown to have a significant affect on the properties of polymer electrolytes, especially those based on polyether–lithium salt systems. In some cases, conductivity increases of more than one order of magnitude have been reported in crystalline PEO-based complexes. In this work, we report on the effects of TiO₂ on a completely amorphous polyether-based system to remove the complication of multiple phases presented by the semi-crystalline nature of PEO. Multinuclear magnetic resonance spectroscopy has shown that the lithium ion environment is changed by the addition of filler. Vibrational spectroscopy shows that the filler influences the disordered-longitudinal acoustic modes (DLAM) in the case of an amorphous polyether and suggests an interaction between the filler surface and the polymer. Positron annihilation lifetime spectroscopy indicates an increase in free volume upon addition of filler to an amorphous polyether–salt complex, coinciding with an apparent increase in polymer mobility as determined from ¹H T₂ NMR measurements. Impedance spectroscopy has shown clear evidence of an inter-phase region that may be more or less conductive than the bulk polymer electrolyte itself. The data support a model which includes conduction through an interfacial region in addition to the bulk polymer

Parenting styles, family structure and adolescent dietary behaviour

Objective To examine associations between parenting styles, family structure and aspects of adolescent dietary behaviour.

Design Cross-sectional study.

Setting Secondary schools in the East Midlands, UK.

Subjects Adolescents aged 12–16 years (n 328, 57 % boys) completed an FFQ assessing their consumption of fruit, vegetables, unhealthy snacks and breakfast. Adolescents provided information on parental and sibling status and completed a seventeen-item instrument measuring the general parenting style dimensions of involvement and strictness, from which four styles were derived: indulgent, neglectful, authoritarian, authoritative.

Results After controlling for adolescent gender and age, analysis of covariance revealed no significant interactions between parenting style and family structure variables for any of the dietary behaviours assessed. Significant main effects for family structure were observed only for breakfast consumption, with adolescents from dual-parent families (P < 0·01) and those with no brothers (P < 0·05) eating breakfast on more days per week than those from single-parent families and those with one or more brother, respectively. Significant main effects for parenting style were observed for all dietary behaviours apart from vegetable consumption. Adolescents who described their parents as authoritative ate more fruit per day, fewer unhealthy snacks per day, and ate breakfast on more days per week than those who described their parents as neglectful.

Conclusions The positive associations between authoritative parenting style and adolescent dietary behaviour transcend family structure. Future research should be food-specific and assess the efficacy of strategies promoting the central attributes of an authoritative parenting style on the dietary behaviours of adolescents from a variety of family structures.