bluuebunny/crossref_metadata_2025 huggingface dataset:
The plant Leclercqia (Lycopsida) in Gondwana: implications for reconstructing Middle Devonian palaeogeography
Authors: MEYER-BERTHAUD BRIGITTE , FAIRON-DEMARET MURIEL , STEEMANS PHILIPPE , TALENT JOHN , GERRIENNE PHILIPPE
Published: May 2003

Abundant and well-preserved material of the ligulate lycopsid genus Leclercqia is reported from a new Middle Devonian locality in northeastern Queensland (Australia). The plants occur in a chert horizon in the Storm Hill Sandstone of the Dosey-Craigie Platform. Lithological data and conodont analyses combined with information from in situ spores provide an age for the plant levels ranging from Eifelian, possibly Middle Eifelian, to Early Givetian. Plant taxonomic identification is based on vegetative and fertile stems that display both external morphology and anatomy. This material represents the best documented occurrence of Leclercqia outside Laurussia and possibly the earliest in Gondwana; it provides evidence that colonization of Gondwana by the species L. complexa was contemporaneous to that of Siberia and Kazakhstan. Analysis of the distribution patterns of L. complexa suggests that it was adapted to a wide range of environments, but within certain limits which we hypothesize to be those of a climatic belt. Such considerations support previous studies using other biological data, such as faunas and palynomorphs, for reconstructing Devonian palaeogeography. They favour a close proximity of Laurussia and Gondwana rather than the occurrence of a wide ocean separating the two palaeocontinents in Middle Devonian times.
Brittle fault evolution of the Montréal area (St Lawrence Lowlands, Canada): rift-related structural inheritance and tectonism approached by palaeostress analysis
Authors: ROCHER MURIEL , TREMBLAY ALAIN , LAVOIE DENIS , CAMPEAU ANDRÉ
Published: May 2003

The Montréal area belongs to the St Lawrence Lowlands, a Cambrian Early Ordovician passive margin of the Iapetus Ocean, later covered by Appalachian Middle to Upper Ordovician foreland deposits. A structural and palaeostress analysis has been carried out in order to reconstruct its tectonic evolution. The structural map has been revised with new data. Palaeostresses are reconstructed based on inversion of fault slip data, and these results are independently corroborated by the microstructural study of calcite mechanical twinning. Field relationships are used to establish the relative chronology of fractures and to deduce the motion on regional faults. The reconstructed structural and tectonic evolution brings to light some relationships between structural inheritance and tectonic events that have affected the area since Early Palaeozoic times. An early NW–SE extension is responsible for N040-trending faults along the northern border of the St Lawrence Lowlands, and for N090- and N120-trending faults cross-cutting the Montréal area. This extension is followed by WNW–ESE and NNW compressions, which have induced reverse motion on pre-existing faults and generated strike-slip conjugate faults. Subsequent NE–SW and NNW–SSE-directed extensions have reactivated previous faults with normal to strike-slip motions. A late NE–SW compression is recorded in the Monteregian plutons. Compressions in WNW–ESE and NNW directions are consistent with Appalachian collisional tectonism, but N040- and N090-trending faults cross-cut Appalachian folds and foreland deposits. Although the early NW–SE extension is consistent with the collapse of the Iapetan margin in Early Palaeozoic times, most of the present geometry of the St Lawrence Lowlands could be attributed to Mesozoic tectonism, recorded as nearly N–S-directed extensional events.
Structural and functional relationships shown by genomic analysis of Capra hircus genes
Authors: FADIEL A. , LITHWICK S. , GANJI G. , MARAI I. F. M.
Published: May 2003

The effect of base composition biases on codon usage patterns was investigated in the goat species Capra hircus, using custom-designed computational tools available within the public domain. Nucleotide frequencies were nearly equal and a slight increase of adenine–thymine (AT) over guanine–cytosine (GC) was detected throughout the dataset. However, this increase showed no influence on the bases at the third codon position (N3). C3 and G3 were found more often than A/T3, suggesting that there was a small or almost no influence of the general base composition on the N3 base composition. To understand more and analyse in-depth influence and interactions between base compositions and codons, further relative synonymous codon usage (RSCU) was investigated. Amino acid usage and the correlation between its usages were also investigated, using both basic sequence analysis and statistical analysis means (measures of correlation). These analyses were utilized to probe whether there were correlations between genes, genomic characteristics and their function. Genes with high GC and those with low GC were also investigated to see to what extent how a gene functions could influence its sequence structure and impose certain structural modifications. This investigation may shed light on many genomic features of Capra hircus genes and would be of significance for future biotechnology/research projects considering Capra for transgenic and advanced genomic initiatives.
Long-term performance of white clover varieties grown with perennial ryegrass under rotational grazing by sheep with different nitrogen applications
Authors: WILLIAMS T. A. , EVANS D. R. , RHODES I. , ABBERTON M. T.
Published: May 2003

Three experiments were carried out to investigate the dry matter production of nine white clover (Trifolium repens L.) varieties grown with the same variety of perennial ryegrass (Lolium perenne L.) and subjected to rotational grazing by sheep over a period of 10 years. The experiments differed only in the nitrogen fertilizer added: no nitrogen, 100 kg/ha per year and 200 kg/ha per year. Dry matter (DM) yields of white clover and perennial ryegrass components of the sward were recorded at approximately 6-week intervals during the growing season.

Without applied nitrogen, 10-year mean white clover annual DM yields ranged from 2·89–4·54 t/ha. Mean clover content for all varieties ranged from 31–50% for the first 9 years, declining to 20% in the 10th year. The most consistently high yielding variety, AberVantage, gave yields greater than 3·5 t/ha in every year. Similar results were observed for the variety Aran. The 10-year mean annual DM yield of the perennial ryegrass companion (variety Talbot) ranged from 4·41–5·57 t/ha depending on the white clover variety in the mixture. Variation in perennial ryegrass DM yield was of a similar range and pattern as for white clover.

In the experiment in which 100 kg N/ha per year was added, 10-year mean white clover annual DM yields ranged from 2·27–3·87 t/ha. The varieties AberVantage and Aran showed yields that fell below 3 t/ha per year in only 1 or 2 years, respectively. Mean clover content for all varieties ranged from 26–38% for the first 9 years, declining to 17·5% in the 10th year. There was no consecutive annual decline in white clover DM yields. The 10-year mean annual DM yields of the perennial ryegrass companion ranged from 6·03–7·57 t/ha.

With applied nitrogen fertilizer of 200 kg N/ha per year (Experiment 3), 10-year mean white clover annual DM yields ranged from 1·21–2·67 t/ha. Mean clover content ranged from 12–27% for the 10 years. AberVantage and Aran showed yields consistently above 2 t/ha. No general decline in white clover DM yields was observed although some varieties showed consecutive annual reductions in years 8, 9 and 10. The 10-year mean annual DM perennial ryegrass yields ranged from 7·27–8·68 t/ha.

The results show that, under rotational grazing by sheep, white clover can give reliably high yields over a 10-year period. With moderate to high applications of nitrogen fertilizer white clover yields were lower than without nitrogen but they were consistent and sufficient to make a considerable impact on forage quality. There was no evidence for a general decline in clover content until the 10th year of the experiment and no cyclical pattern of annual variation in white clover yield was observed. The implications of these results for the role of white clover in UK agriculture are discussed.
Nitrogen fertilizer replacement value of sewage sludge, composted household waste and farmyard manure
Authors: PETERSEN J.
Published: May 2003

Field experiments were undertaken during 1998–2000 at Askov Experimental Station and Lundgård Experimental Site, Denmark, to investigate the fertilizer value of anaerobic and aerobic sewage sludges (SS1 and SS2), composted household waste (Compost) and farmyard manure (FYM). The organic residues were applied at two rates with or without supplementary mineral nitrogen (N). The effects of residue application on spring cereal dry matter (DM) yield and N-offtake were related to reference treatments with increasing rates of calcium ammonium nitrate (CAN). DM yields at the high application rates of aerobic sewage sludge (198 kg N/ha/year) and farmyard manure (300 kg N/ha/year) were comparable to the reference treatments receiving 90 kg mineral-N/ha/year. The comparable high application rate of anaerobic sewage sludge was 138 kg N/ha/year only and the DM yield was less. In contrast, the yield effect of Compost was very poor; even the high application rate of 321 kg N/ha/year yielded less than the low application rates of aerobic sewage sludge and farmyard manure, 66 and 100 kg N/ha/year, respectively.

The nitrogen fertilizer replacement value (NFRV) of the organic residues was estimated for all four combinations of the response variables DM-yield and N-offtake and the independent variables of total-N and ammonium-N applied. NFRV was in the range 49–68% for the sewage sludges and FYM based on the DM-yield[ratio ]total-N relation, and slightly smaller for the N-offtake[ratio ]total-N relation, 29–53%. The highest values were obtained for the aerobic sewage sludge, having a potential manurial value comparable to FYM. In contrast, the NFRV of Compost was low, about 10%.

The concentration of ammonium-N in organic residues and manures is often used for predicting the fertilizer value. Ammonium-N based NFRV of 160–210% for the sewage sludges indicate that water extractable ammonium-N underestimates the NFRV, probably due to the content of easily degradable organic matter in digested sewage sludge. The estimated NFRV for Compost was above 100% but connected with high uncertainty. In contrast, the ammonium-N based NFRV for FYM was only 70–87%, probably due to ammonia volatilization caused by incomplete incorporation of large quantities and the high ammonium-N[ratio ]total-N ratio in this residue.
Effect of silica content on rice straw ruminal degradation
Authors: AGBAGLA-DOHNANI A. , NOZIÈRE P. , GAILLARD-MARTINIE B. , PUARD M. , DOREAU M.
Published: May 2003

The present study investigated how increasing silica content modifies the chemical and morphological characteristics and microbial degradation of rice straw. Two rice straws grown on culture media with different silica contents were collected and analysed for chemical and morphological composition and ultrastructure. Silica content (g/kg DM) of the two straws was high (98·0, straw H) and low (0·0, not detected, straw L). The ground (2 mm) straws were incubated in the rumen of three ruminally cannulated cows for 4, 8, 16, 24, 48 and 96 h for in sacco degradability measurements. The main fractions (stem, leaf sheath and blade) of each straw were incubated for 24 h. Kinetics were fitted to an exponential model with lag time. Scanning electron microscopy was used to examine intact fragments of stems and fragments incubated for 6, 24, 72 and 96 h in cow rumen. X-ray analysis was carried out on non-incubated fragments for silica mapping. A reduction of stem content from 320 to 270 g/kg straw, and an increase in leaf sheath content from 360 to 400 g/kg straw, were found for an increase in silica content from 0 to 100 g/kg DM. Chemical composition differed little between straws H and L, except for ash and silica contents. The ash originated mainly from the leaves and increased with silica content from 70 to 140 g/kg DM. The DM degradability was lower in the H than in the L straw. This reduction came mainly from a lower non-NDF component degradation in straw H. Stems were more degraded than leaf fractions for DM, NDF and non-NDF components; their degradation was depressed in the H straw. X-ray analysis showed that the deposition of silica on the stem epidermis was different, with a thick layer on H stems and no deposition on L stem surfaces. As a consequence, microbial colonization and degradation were faster on the epidermis of straw L. Epidermal silica did not hinder degradation from the internal cavity.
Progress in breeding perennial forage grasses for temperate agriculture
Authors: WILKINS P. W. , HUMPHREYS M. O.
Published: May 2003

Breeding of temperate forage grasses is aimed at improving the economic and environmental sustainability of production from cattle and sheep. The primary objective is to ensure that forage can be the main source of feed for ruminants. This requires consistent production of herbage with a high feeding value, usually under nitrogen-limiting conditions. The most important traits affecting the feeding value of herbage are in vitro dry matter digestibility (DMD), the ratios of crude protein, water-soluble carbohydrate and fibre, and the concentration of alkaloid toxins. Improvements in these primary quality traits must be combined with good plant persistency, adequate tolerance to a range of environmental stresses, adequate resistance to a large number of different pathogens and invertebrate pests, and adequate seed yield. Forage grasses also have considerable potential to produce material for refining, to provide protein extracts for feeding to monogastric animals and carbohydrate for fermentation into fuel or into feedstocks for other industries.
Persistence of differences between sheep in methane emission under generous grazing conditions
Authors: PINARES-PATIÑO C. S. , ULYATT M. J. , LASSEY K. R. , BARRY T. N. , HOLMES C. W.
Published: May 2003

Four low and four high methane (CH4) emitters were selected from a flock of 20 Romney sheep on the basis of CH4 production rates per unit of intake, measured at grazing using the sulphur hexafluoride (SF6) tracer technique. Methane emissions from these sheep were monitored at grazing for four periods (P): October, November, January and February 1999/2000. All measurements were carried out on perennial ryegrass/white clover pasture under generous herbage allowance, and the sheep were maintained on similar pastures during non-measurement periods. The tracer technique was used for all the CH4 measurements and feed DM intake was calculated from total faecal collection and estimated DM digestibility. Data for liveweight (LW), gross energy intake (GEI) and CH4 emission were analysed using split-plot analysis of variance. In addition, a between-period rank order correlation analysis was carried out for CH4 emission data.

Low CH4 emitters were heavier (P<0·05) than the high emitters in all the periods, but they did not differ (P<0·05) in their gross energy intakes (GEI: MJ/kg LW0·75). Low and high CH4 emitters consistently maintained their initial rankings in CH4 yield (% GEI) throughout the subsequent periods and the correlation analysis of rank order for CH4 yield showed strong between-period correlation coefficients, although this was weaker in the last period. It is suggested that feeding conditions that maximize feed intake (e.g. generous allowance of good quality pasture under grazing) favour the expression and persistence of between-sheep differences in CH4 yield.
MATERNAL AND NEONATAL FACTORS INFLUENCING PREMATURE BIRTH AND LOW BIRTH WEIGHT IN AUSTRALIA
Authors: MOHSIN M. , WONG F. , BAUMAN ADRIAN , BAI JUN
Published: May 2003

This study identified the influences of neonatal and maternal factors on premature birth and low birth weight in New South Wales, Australia. Bivariate and multivariate analyses were used to explore the association of selected neonatal and maternal characteristics with premature birth and low birth weight. The findings of this study showed that premature birth and low birth weight rate significantly varied by infant sex, maternal age, marital status, Aboriginality, parity, maternal smoking behaviour during pregnancy and maternal hypertension. First-born infants, and infants born to mothers aged less than 20 years, or who were single, separated/divorced, Aboriginal or who smoked during the pregnancy, were at increased risk of being premature or of low birth weight. This study also found that risk factors for premature births and low birth weight were similar in both singleton and multiple births. Gestational age was confirmed to be the single most important risk factor for low birth weight. The findings of this study suggest that in order to reduce the incidence of low birth weight and premature births, health improvement strategies should focus on antismoking campaigns during pregnancy and other healthcare programmes targeted at the socially disadvantaged populations identified in the study.
THE ASSOCIATION BETWEEN HIV AND FERTILITY IN A COHORT STUDY IN RURAL TANZANIA
Authors: HUNTER SUSAN-CATHERINE , ISINGO RAPHAEL , BOERMA J. TIES , URASSA MARK , MWALUKO GABRIEL M. P. , ZABA BASIA
Published: May 2003

Recent studies in sub-Saharan Africa have shown that fertility is reduced among HIV-infected women compared with uninfected women. The size and pattern of this fertility reduction has important implications for antenatal clinic-based surveillance of the epidemic and also for estimates and projections of the demographic impact of the epidemic. This paper examines the association between HIV and fertility in Kisesa, a rural area in Tanzania, where HIV prevalence among adults is about 6% and gradually increasing. The analysis is based on data obtained through a demographic surveillance system in Kisesa during 1994–98 and two large sero-surveys of all residents in 1994–95 and 1996–97. The HIV-associated fertility reduction among women was investigated by estimating fertility rates by HIV status and prevalence rates by fertility status. A substantial reduction (29%) was observed in fertility among HIV-infected women compared with HIV-uninfected women. The fertility reduction was most pronounced during the terminal stages of infection, but no clear association with duration of infection was observed. Use of modern contraception was higher among HIV-infected women. However, both among contracepting and noncontracepting women, a substantial reduction in fertility was seen among HIV-infected women.
A NOTE ON THE FETAL–INFANT MORTALITY PROBLEM
Authors: WILLIAMSON P. , WOODS R. I.
Published: May 2003

This paper considers the age pattern of mortality between conception and first birthday. It highlights the various problems that still limit our understanding of the ways in which the age components of mortality are associated, especially during the perinatal period. A mathematical function is fitted which captures the interaction between six mortality components for a typical high mortality society, one in which the infant mortality rate is 150 per thousand live births. This experiment helps to clarify the need to link infant with fetal mortality, to conduct further research on the level of risk in each component, and to consider the cumulative early-age mortality profile in its entirety.
EFFECTS OF ORAL CONTRACEPTIVE USE ON BODY MASS INDEX AND BLOOD PRESSURE AMONG FEMALE VILLAGERS IN NORTH-EAST THAILAND
Authors: MURAYAMA NOBUKO , MATSUNAGA AYU , TANGBANLUEKAL LADDA , TANTAWIWAT SUWALEE , OHTSUKA RYUTARO
Published: May 2003

The use of contraceptives has become prevalent among females in Thailand in the past 20 years, and oral contraceptive use has been suggested to trigger changes in fat intake, energy expenditure, fat metabolism and blood pressure. Based on field investigations of 391 married women aged 20 years or over in Yasothon Province, North-east Thailand, this study aims to elucidate the effects of oral contraceptive use on body mass index (BMI: kg/m2 ) and blood pressure, taking into account reproductive histories and socioeconomic conditions. The proportion of obese (BMI> 25) subjects was high in the age groups 30–39, 40–49 and 50–59, accounting for, respectively, 39·4%, 51·1% and 48·5% of these populations. The proportion of women with hypertension (90/140 mmHg) was 23·7%, 18·5% and 26·2% in the 40–49, 50–59 and 60–69 age groups. Current contraceptive practices in the studied population included sterilization by operation, oral contraception and injection. These methods accounted for 43·0%, 12·8% and 8·2% of the population, respectively. Sociodemographic factors such as reproductive history, years of education and household income were not significantly related to BMI or to blood pressure (ANOVA with age adjustment). In contrast, oral contraceptive users had significantly higher BMIs and diastolic blood pressures (p<0·01, ANOVA with age adjustment). Multiple regression analysis also revealed that oral contraceptive use was a weak but significant contributing factor to both high BMI and blood pressure when sociodemographic factors were taken into account and controlled for statistically. It can thus be concluded that the use of contraceptive pills, which contain oestrogen and progestin and are provided free of charge to Thai women, tend to increase BMI and to elevate blood pressure.
DETERMINANTS OF VARIATION IN ADULT BODY HEIGHT
Authors: SILVENTOINEN KARRI
Published: May 2003

Final body height is achieved as the result of a combination of genetic and environmental factors. The aim of this article is to review past studies on body height that have followed different scientific traditions. In modern Western societies, about 20% of variation in body height is due to environmental variation. In poorer environments, this proportion is probably larger, with lower heritability of body height as well as larger socioeconomic body height differences. The role of childhood environment is seen in the increase in body height during the 20th century simultaneously with the increase in the standard of living. The most important non-genetic factors affecting growth and adult body height are nutrition and diseases. Short stature is associated with poorer education and lower social position in adulthood. This is mainly due to family background, but other environmental factors in childhood also contribute to this association. Body height is a good indicator of childhood living conditions, not only in developing countries but also in modern Western societies. Future studies combining different scientific traditions in auxology are needed to create a more holistic view of body height.
Fighting for a Closed Shop: The 1931 Lima Bakery Workers' Strike
Authors: DRINOT PAULO
Published: May 2003

This article uses the 1931 strike by the Lima bakery workers' union as an optic through which to study the politicisation of industrial relations in the context of the emergence of populist politics in Peru. Faced with a loss of control over the bakery workforce and a hostile and ineffective system of collective bargaining, the union turned to an alternative strategy in its attempts to gain control over the workforce and the productive process. It presented itself as a bulwark against labour militancy and sought to establish political ties to the Sánchez Cerro government. Although the strategy was largely unsuccessful, this case study illustrates the extent to which Peruvian workers played an active role in the construction of populist politics in the 1930s.
Institutional Modernisation and the Legacy of Corporatism: The Case of Port Reform in Brazil
Authors: DOCTOR MAHRUKH
Published: May 2003

This article analyses some of the difficulties of institutional modernisation based on a study of Brazilian port reform in the 1990s. It explains how and why Brazilian business managed to organise collective action for dramatic reform of the port structure and labour regime, but was unable to maintain the consensus to ensure full implementation. It emphasises how the formal rigidities and informal outcomes of the corporatist institutional structure hampered an efficient pace of modernisation. The analysis applies two complementary theoretical approaches, institutional analysis and the logic of collective action, to illuminate the evolution of Brazilian corporatism in the context of a more democratic society and open market economy.
An unlikely success: South Africa and Lesotho's election of 2002
Authors: Southall Roger
Published: May 2003

The Mbeki government's failure to take action against the blatantly undemocratic behaviour of the Mugabe regime in Zimbabwe, despite its commitment to the peer review mechanism proposed under the New Partnership for African Development, is highlighted by South Africa's armed intervention into Lesotho to quell post-electoral disturbances in 1998. Although initially accompanied by immense controversy, the South African military and diplomatic involvement was to prove crucial to a restructuring of Lesotho's previously recalcitrant Defence Force, and to the promotion of inter-party negotiations that led to the adoption of a new and more appropriate electoral system. Alongside other international pressures, these initiatives led to a further election in 2002, whose undoubtedly legitimate outcome appears to have laid firm foundations for democratic consolidation and stability. Despite this ‘unlikely success’, and despite its formal commitment to an idealist foreign policy, the South African government has consciously downplayed its role in promoting democracy in Lesotho. The article argues that this is because of the exceptionality of that country, and South Africa's reluctance to have the use of force used as a precedent by its critics for cajoling it into adopting a more activist stance for dealing with the more complex situation in Zimbabwe.
Presidentialism and clientelism in Africa's emerging party systems
Authors: van de Walle Nicolas
Published: May 2003

This paper analyses the parties and party systems that have begun to emerge in sub-Saharan Africa's fledgling multiparty systems. Using a data base of 87 legislative elections convened in the 1990s, the paper identifies three trends. The position of parties late in the decade is primarily tributary of their performance in the first multiparty election conducted in the early 1990s. Parties that won founding elections are almost invariably still in power. Secondly, the typical emerging party system has consisted of a dominant party surrounded by a large number of small, unstable parties. Thirdly, party cleavages have been overwhelmingly ethno-linguistic in nature, while ideological and programmatic debates have been muted and rare. The second half of the paper provides tentative explanations for these striking patterns. It emphasises the illiberal nature of most of the new African democracies, their characteristic centralisation of power around the presidency, and the pervasive clientelism that structures the relationship between the state and the citizenry. These characteristics shape the incentives faced by individual politicians and thus much of their behaviour.
The self-designed career in later life: a study of older portfolio workers in the United Kingdom
Authors: PLATMAN KERRY
Published: May 2003

Secure, full-time jobs that last until the statutory retirement age have dwindled. Meanwhile, flexible forms of work have grown and are increasingly promoted as promising solutions to the ‘problem’ of economic inactivity in later life. Government committees, campaigning groups and management authors have warmly embraced the possibilities of self-employment, contract work, freelancing, consultancy and part-time work for those who need or want to work beyond the age of 50 years. Portfolio-type jobs appear to offer choice, opportunity and control for individuals in the final stages of a career. Working for a range of clients, so the argument goes, allows older people to bypass age-discriminatory barriers to employment and negotiate their own transition into retirement, but very little research has examined the viability of portfolio work in later life. This paper draws on a three-year study of freelance employment in the British media industry. The aim was to understand the conflicts, barriers and opportunities involved in portfolio careers in later life. It applies a critical realist perspective. The study found that older individuals were vulnerable to job insecurity and financial risk because of their diminishing networks and skills. They experienced a reduced flow of commissions, which hampered their ability to exert choice and control in the labour market.
Promoting independence: but promoting what and how?
Authors: SECKER JENNY , HILL ROBERT , VILLENEAU LOUISE , PARKMAN SUE
Published: May 2003

‘Promoting independence’ is a central theme of recent United Kindgdom health and social care policy development but is rarely defined. Instead it is generally assumed that we know what independence means. Based on a review of the literature on independence in older age, this paper examines the terms and meanings. While the most common conceptualisation equates independence with the absence of reliance on others, for older people themselves independence is a broader concept that encompasses not only self-reliance but also self-esteem, self-determination, purpose in life, personal growth and continuity of the self. Drawing on previous work in the field of health promotion, we therefore put forward a model that takes older people's views into account and that reconceptualises independence as two intersecting dimensions representing levels of dependence and levels of independence. While dependence equates with reliance on others, independence can be seen as subjectively self-assessed lived experience. Thus it becomes possible to combine high levels of dependence with high levels of experienced or felt independence, a particularly pertinent combination for service providers. Finally we examine the ways in which independence thus conceptualised can be promoted at the individual, institutional, community and societal levels.
Teacher cognition in language teaching: A review of research on what language teachers think, know, believe, and do
Authors: Borg Simon
Published: May 2003

This paper reviews a selection of research from the field of foreign and second language teaching into what is referred to here as teacher cognition – what teachers think, know, and believe and the relationships of these mental constructs to what teachers do in the language teaching classroom. Within a framework suggested by more general mainstream educational research on teacher cognition, language teacher cognition is here discussed with reference to three main themes: (1) cognition and prior language learning experience, (2) cognition and teacher education, and (3) cognition and classroom practice. In addition, the findings of studies into two specific curricular areas in language teaching which have been examined by teacher cognition – grammar teaching and literacy – are discussed. This review indicates that, while the study of teacher cognition has established itself on the research agenda in the field of language teaching and provided valuable insight into the mental lives of language teachers, a clear sense of unity is lacking in the work and there are several major issues in language teaching which have yet to be explored from the perspective of teacher cognition.
Favoured or oppressed? Married women, property and ‘coverture’ in England, 1660–1800
Authors: BAILEY JOANNE
Published: May 2003

In the eighteenth century, the condition of English wives under ‘coverture’ was both defended as one of privilege and attacked as worse than slavery. This article suggests that married women were not in reality confined within coverture's regulations on credit and property ownership. Their economic activities were fairly broad and flexible and they had an instinctive sense of possession over some goods during wedlock, perceiving their contributions to marriage as a pooling of resources for familial benefit. It will be suggested that wives did not necessarily think that their conduct in acting as if some marital property was legally theirs was illegitimate, because it was facilitated by coverture and the legal devices that allowed it to function.
The employment and retirement of older men, 1851–1881: further evidence from the census
Authors: WOOLLARD MATTHEW
Published: May 2003

Using microdata samples from the 1851 and 1881 censuses of England and Wales, this article explores patterns in the employment and retirement of older men in the second half of the nineteenth century. The article argues that male labour-force participation rates were stable over these years, and indicates that the major decrease did not occur until after 1881. Despite this static picture of employment of older men, there were structural changes in the economy, demonstrated here by alterations in occupational profile. Those occupational groups shown to be in decline were more likely to have an ageing workforce. Changing age profiles of certain occupations are reported, giving evidence of deskilling and the marginalisation of older men in the workforce through technological change. This article also suggests that differences in household composition where older men were present may be related to economic activity.
The institution of retirement on Scanian estates in the nineteenth century
Authors: LUNDH CHRISTER , OLSSON MATS
Published: May 2003

This article examines the institution of retirement on some estates in Scania, the southernmost part of Sweden, in the nineteenth century. It is obvious that tenant farmers on the estates were practising the same retirement system as was customary among freeholders, that is they were entering into retirement contracts with their offspring or with a non-relative, making over the farm in exchange for board and lodging for the rest of their lives. The retirement age was about 60 for men and somewhat less for women. In this respect there was no difference between tenant farmers and freeholders. However, due to differences in property conditions and land tenure, there were other differences between these groups. Freeholders were usually able to ensure for themselves considerably better pension rights than could estate tenants. Furthermore, there are clear indications that estate owners, in certain cases, opposed early retirement or intervened in the selection of new tenant farmers as well as in the level of the pension. Possibly as a result, it was more common among estate tenants to agree a retirement contract with a non-relative than it was among freeholders.
To run or hide? Age‐dependent escape behaviour in the common flat lizard (Platysaurus intermedius wilhelmi)
Authors: Whiting Martin J. , Lailvaux Simon P. , Reaney Leeann T. , Wymann Monica
Published: May 2003

Flat lizards Platysaurus intermedius wilhelmi occur on small discrete rock outcrops in Mpumalanga Province, South Africa. These rock outcrops are structurally simple and this, combined with the lizard's behaviour (ambush foraging in the open), make them ideal for field studies of anti‐predatory behaviour. Lizards were approached in the field and how escape behaviour was influenced by habitat and age‐sex class was recorded. Juveniles (c. 4 months of age) responded quite differently to an approaching human ‘predator’ compared with adult males and females (which responded similarly). Compared to adults, juveniles allowed a closer approach by the investigator; took longer to find a refuge and therefore fled further; were more likely to remain visible in the open and maintain visual contact with the investigator; and more likely to flee into vegetation when given the opportunity to take refuge in a crevice. We suggest that because a greater suite of predators (including arthropods living in rock crevices) feed on small juvenile lizards, this may affect their choice of refuge and result in the avoidance of crevices when chased. Finally, because juveniles were frequently found on small rock outcrops, the influence of rock outcrop area on anti‐predatory behaviour was tested. Escape behaviour (time to refuge) was independent of rock outcrop area.
More injuries in left‐footed individual lizards and Sphenodon
Authors: Seligmann Hervé , Beiles Avigdor , Werner Yehudah L.
Published: May 2003

In lizards and Sphenodon, often the fourth toes of individuals with intact tails have more subdigital lamellae on the right than on the left side, and the opposite situation frequently occurs in individuals with injured tails. The difference between intact and injured individuals in morphological directional asymmetry was statistically significant (P<0.05) in 11.4% among 193 species from various lizard families. Lizard families varied in extent and direction of association, but no phylogenetic constraints were detected within genera. Statistical significance was greater in samples from homogenous geographic origin than from heterogeneous ones. Among gekkonid species, the difference was stronger in those with cursorial (terrestrial) habits, than in those with scansorial (rupestral or arboreal) habits. In Scincidae, loss seems more often lethal in left‐footed than in right‐footed individuals. Statistically significant associations between morphological left‐side dominance and tail injury exist also in three independent lineages with reduced limbs (Anguidae, Scincidae and Teidae). Hence such association is probably not a result of limb function. Rather, left‐side dominance seems to be the symptom of an unknown, perhaps organism‐wide, detrimental trait. Polymorphism in morphological dominance existed in all species, suggesting advantages and disadvantages in different situations to both phenotypes. We propose the hypothesis that an inversion of side dominance may occur in a single trait without systematic inversion of side dominance in all traits of the body. Inversion in a single trait causes incompatibility in multiple‐trait functions. Such a mechanism, rather than cultural conventions, could increase accident proneness also in left‐handed Homo sapiens, and could explain increased proneness to accident and warfare mortality in left‐handed men, beyond the possible involvement of cultural factors.
Morphometric analysis on ecomorphologically equivalent cichlid species from Lakes Malawi and Tanganyika
Authors: Kassam Daud D. , Adams Dean C. , Hori Michio , Yamaoka Kosaku
Published: May 2003

Landmark‐based geometric morphometric techniques were used to test the hypothesis that Petrochromis spp. from Lake Tanganyika are ecomorphologically equivalent to Petrotilapia spp. from Lake Malawi. Both genera are epilithic algal feeders and inhabit the rocky shores of their respective lakes. We investigated the morphological component of the ecomorphology hypothesis by investigating body shape, using landmark‐based morphometric techniques. A MANOVA revealed significant differences among species and an ordination of all species along the first two CV axes showed clear separation of the two genera in the morphospace with Petrochromis fasciolatus as an intermediate. A thin‐plate spline analysis revealed that Petrochromis spp. had a deeper, broader anterior body, larger gape, shorter anal fin base and narrower caudal peduncle than Petrotilapia spp. Basically, differences between lakes were found, but there were no similarities or clusters of presumptive ecomorphs. Based on such results, we reject the hypothesis of morphological equivalence between these two genera. However, considering the non‐significant difference in body shape revealed between P. fasciolatus, Petrotilapia genalutea and Petrotilapia‘mumbo blue’, we conclude that these three species represent morphological equivalence and hence display a best example of convergent evolution.
Calcium as a limiting resource to insectivorous bats: can water holes provide a supplemental mineral source?
Authors: Adams Rick A. , Pedersen Scott C. , Thibault Katherine M. , Jadin Jenna , Petru Brad
Published: May 2003

Data are presented on a bat assemblage captured among 10 water holes in Colorado over 5 years. The assemblage consists ofMyotis ciliolabrum,M. evotis,M. lucifugus,M. thysanodes,M. volans,Eptesicus fuscus,Lasiurus cinereus,Lasionycteris noctivagansandCorynorhinus townsendii. Results show that reproductive females and juveniles are captured in higher frequencies at water holes containing higher water hardness and that water hardness correlates highly significantly with dissolved calcium content. Also presented are laboratory test data on the stomach volume ofEptesicus fuscusthat provide a model for understanding the effect of dissolved calcium content in water as a significant resource. These data indicate that water holes provide supplemental sources of calcium for bats not provided by diet.
Diet of the maned wolf (Chrysocyon brachyurus) and its role in seed dispersal on a cattle ranch in Brazil
Authors: Santos Eliana F. , Setz Eleonore Z. F. , Gobbi Nivar
Published: May 2003

The maned wolf Chrysocyon brachyurus is the largest canid inhabiting South America. Its geographic distribution includes the open fields of Brazil's central area, which is currently undergoing agricultural expansion. The diet of the maned wolf and its seasonal variation was determined on a dairy cattle ranch (São Luís farm, 566 ha) in the State of Minas Gerais, Brazil. From January to December faeces of the maned wolf were collected monthly (n= 150 scats; 397 food item occurrences). Twenty‐nine taxa were identified from scats, 18 of animal origin (46% or 183 occurrences) and 11 of plants (54% or 214 occurrences). The fruits of Solanum lycocarpum were the dominant food item in our study (29%). Mammals contributed 13%, arthropods 12%, birds 11% and reptiles 2% of the food items. Arthropods and fruits were prevalent in the rainy season and mammals in the dry season. As expected for a heavily farmed region, frugivory results were at the lower end of the diversity scale (9–33 species) and included four old garden species. No previous study of the diet of maned wolf has registered as many species of Solanaceae as this one. Although dietary richness was lower, the main food items (wolf fruit, armadillos, rodents, birds) were the same as study sites in ‘cerrado’ and upland meadows. In this region, the open habitats occupied by the maned wolf were previously covered by Atlantic forest, suggesting that landscape modification such as cattle ranching has opened new frontiers for distribution expansion of the maned wolf. The impact of loss of dietary richness and the increase in Solanaceae on the survival of the maned wolf need to be evaluated.
Swimming kinematics and wake elements in a worm‐like insect: the larva of the midge Chironomus plumosus (Diptera)
Authors: Brackenbury John
Published: May 2003

The kinematics and hydrodynamics of swimming chironomid larvae were investigated with the aid of videography and dye streamers used to visualize near‐body flow. Chironomids employ a characteristic ‘figure‐of‐eight’ swimming technique based on high‐amplitude side‐to‐side bending of the body. These scissor‐like movements produce relatively slow (two body lengths (BL) s−1) forward motion but also serve to support the weight of the insect against its own negative buoyancy. The main wake element identified by the present technique consisted of a discrete ring vortex with an external diameter of c. 0.3 BL which was shed to the rear of the body towards the end of each half‐stroke. During level swimming, the jet of the vortex was directed 10° below the horizontal plane indicating that it was mainly providing thrust. An additional, but poorly defined, flow was associated with the rapid downwards motion of the head at the start of each half‐stroke and it is proposed that this contributes to the vertical force needed to support the weight of the body during swimming.
First evidence for photoperiodic regulation of the life cycle in a millipede species, Polydesmus angustus (Diplopoda: Polydesmidae)
Authors: David J.‐F. , Geoffroy J.‐J. , Célérier M.‐L.
Published: May 2003

The hypothesis that the periods of dormancy previously described in the millipede Polydesmus angustus may be photoperiodically induced diapauses was tested experimentally. In this species, biennial individuals exhibit two successive periods of dormancy: aestivation in the penultimate stadium (stadium VII) and reproductive dormancy in the adults, which emerge in autumn. It was first established that the reproductive dormancy is not a thermally controlled state of quiescence. When adults emerging in autumn were kept at 16 °C under natural photoperiod, their reproduction was delayed for several months in comparison with adults emerging in spring at similar temperatures. This indicates that the reproductive dormancy begins with a period of diapause. Further experiments provided evidence of a photoperiodic induction of the adult diapause. When millipedes were reared under short day length (L:D 12:12 h) throughout their development, they required more time to reproduce than millipedes reared under long day length (L:D 16:8 h) at the same temperatures. Photoperiod influenced reproduction in females, but no significant effects were detected in adult males. On the other hand, stadium VII was markedly longer at L:D 16:8 h than at L:D 12:12 h in both sexes, which strongly suggests that aestivation is also induced by photoperiod. However, the effects on the duration of stadium VII varied among individuals, some of which showed no response to long days. This study is the first to document photoperiodic regulation of the life cycle in the class Diplopoda, a trait common in other classes of terrestrial arthropods.
Aphids of sub-Antarctic Îles Crozet and Kerguelen: species diversity, host range and spatial distribution
Authors: HULLÉ MAURICE , PANNETIER D. , SIMON J.-C , VERNON P. , FRENOT Y.
Published: May 2003

The native terrestrial food web of sub-Antarctic islands is dominated by decomposers with rare herbivores and almost no predators. As a consequence of increasing human activities, the number of alien plants and invertebrates species, including phytophagous species, has been dramatically rising on these islands. These repeated introductions seem likely to have a great impact on the ecosystem functioning. This is the first detailed study on species diversity, host range and spatial distribution of aphids on French
sub-Antarctic islands. Six cosmopolitan and polyphagous aphid species have been recorded
on these islands. Five species have been found in the wild where they colonized native and
introduced plants, and one species was confined to a glasshouse. Aphids colonized a littoral
band and were limited to below 200 m a.s.l. Their spatial distribution is constrained by
host plant distribution and temperature. The two dominant species, Myzus ascalonicus
and Rhopalosiphum padi, are obligately parthenogenetic in these islands and have been
observed to be active on plants during winter. The other species are also presumably obligate
parthenogens because of the absence of host plants where sexual reproduction can occur.
We suggest that polyphagy and parthenogenesis are major biological traits that influence
colonization success by aphids in a sub-Antarctic environment.