bluuebunny/crossref_metadata_2025 huggingface dataset:
Fertility norms and son preference in Morocco and Tunisia: does women's status matter?
Authors: Obermeyer Carla Makhlouf
Published: July 2008

This paper investigates the normative and behavioural dimensions of son preference in Morocco and Tunisia, using data from the Demographic and Health Surveys of the two countries. It considers three measures of son preference: (1) mothers' ideal number of children, and any preference for having more sons than daughters; (2) the desire for additional children, given their existing family; (3) reported use of contraception in relation to the existing number of children of each sex. The analyses indicate a moderate preference for sons in both countries, and suggest that this preference is somewhat stronger in Tunisia. These findings are interpreted within the cultural context of the two countries, and in particular societal notions of women's status.
Racial differences in the relationship between infant mortality and socioeconomic status
Authors: Stockwell Edward G. , Goza Franklin W.
Published: July 2008

This paper presents an ecological analysis of the relationship between infant mortality and economic status by race in metropolitan Ohio, using census data on mother's residence, and economic status determined by the percentage of low income families living in each area. White–non-white comparisons for total infant mortality are examined for the US censuses of 1960, 1970, 1980 and 1990; and more detailed period- and broad cause-specific rates are presented for 1990. A pronounced inverse association is found between income status and infant mortality for whites, but not for non-whites. Non-white post-neonatal death rates were higher for the lowest income area, but for neonatal mortality, total infant deaths, and exogenous and endogenous cause-specific death rates, there was no discernible socioeconomic differential. It is concluded that low income whites and non-whites at all income levels have infant mortality rates that are substantially higher than the overall rate for the population. Policy implications are discussed.
Family formation patterns among migrant women in Sydney
Authors: Yusuf Farhat , Siedlecky Stefania
Published: July 2008

A demographic survey among a probability sample of 980 married migrant women was carried out in Sydney in 1988. The sample included 507 Lebanese, 250 Turkish and 223 Vietnamese women. The study revealed differences in family formation patterns within and between the three groups and between them and the general population. Family size had declined among all three groups compared with their family of origin, and it was clear that the younger women would not achieve the same family sizes as the older women. Migrant women tended to marry earlier than the general population and to start their families earlier. While they showed a strong preference for their children to marry within their own ethnic and religious group, nearly one-third said it was up to the choice of the individual. Overall, the future family size of younger migrant women is expected to converge towards the Australian norm. Migrant families are in a state of transition between two cultures which needs to be recognised by health and family planning service providers.
Relationship between survival status of first child and subsequent child death
Authors: Rahman M. M. , Kabir M. , Amin R.
Published: July 2008

This paper examines the association between infant mortality of the first born and subsequent children using data from rural Bangladesh collected during the period 1971–82. It shows that birth spacing and age of mother at the time of the second birth are important predictors of the survival status of the first child. The findings are discussed in terms of policy implications.
The fertility transition in Cuba and the Federal Republic of Korea: the impact of organised family planning
Authors: Noble Jeanne , Potts Malcolm
Published: July 2008

South Korea and Cuba are dissimilar in religion, economy, culture and attitudes toward premarital sexual relations. In 1960, Korea instituted a national family planning programme to combat rapid population growth. Cuba explicitly rejected Malthusian policies, but made family planning universally available in 1974 in response to health needs. Both countries have undergone rapid fertility declines and today have less than replacement level fertility. Both countries have also used a similar mixture of methods, including a high prevalence of female sterilisation. Abortion has played a major role in the fertility decline of both countries, rising in the first half of the fertility transition and then falling, although remaining a significant variable in the second half. It is concluded that access to contraception, voluntary sterilisation, and safe abortion has a direct impact on fertility and has been associated with a rapid fall in family size in two very different countries.
Mass media messages and reproductive behaviour in Nigeria
Authors: Bankole A. , Rodríguez G. , Westoff C. F.
Published: July 2008

This paper examines the effects of exposure to mass media messages promoting family planning on the reproductive behaviour of married women in Nigeria using cross-sectional data. Longitudinal data are also used to ensure that exposure to media messages pre-dates the indicators of reproductive behaviour. Cross-sectional analysis suggests that: (1) contraceptive use and intention are positively associated with exposure to mass media messages, and (2) women who are exposed to media messages are more likely to desire fewer children than those who are not exposed to such messages. Similarly, analysis of the longitudinal data shows that exposure to mass media messages is a significant predictor of contraceptive use. Thus, exposure to mass media messages about family planning may be a powerful tool for influencing reproductive behaviour in Nigeria.
Factors affecting use of contraception in Matlab, Bangladesh
Authors: Khan Mehrab Ali
Published: July 2008

This study examines the relationship between family planning, perceived availability of contraceptives, and sociodemographic factors in rural Bangladesh. Data are from the 1990 KAP survey in the Matlab treatment and comparison areas, using a sample of about 8500 married women of reproductive age. The contraceptive prevalence rate was 57% in the treatment area but substantially lower in the comparison area where mainly traditional methods of family planning were used by women who did not know of a source of supply of contraceptives. Education has no effect on contraceptive use in the treatment area but in the comparison area, modest but consistent differentials in use by level of education were found. Number of living children is the best predictor for contraceptive use, followed by number of living sons, and the attitude of respondents and their husbands towards family planning.
Prior and proximate causes of infant survival in Ghana, with special attention to polygyny
Authors: Amankwaa Adansi A.
Published: July 2008

This study examines the role of marriage form in infant mortality and tests the relative effects and mechanisms through which polygyny affects infant survival. A sample of infants born in the 5 years preceding the 1988 Ghana Demographic and Health Survey was used. A causal model was constructed and polygyny was found to be an important mediating factor in understanding infant survival. The findings highlight the relevance of family structure (polygyny) as an intervening factor, but also reveal the complex role of ethnicity, dietary supplement and birth interval in accounting for infant survival.
Influence of family head's reproductive behaviour on the use of modern contraceptive methods by other members of the family in rural Bangladesh
Authors: Kamal Nashid
Published: July 2008

A study in Bangladesh showed that the probability of use of modern contraception by eligible family members of a household increases significantly if the household head himself is a user. Multinomial logistic regression showed that contraceptive use was also significantly related with maternal age, parity, education, socioeconomic status and experience of child mortality. Inclusion of ever use of modern contraceptives by the family head or his wife, showed family head's religiosity to be a significant predictor of use, apart from his age and parity, and after controlling for socioeconomic correlates.
Influence of body mass index and slimming habits on menstrual pain and cycle irregularity
Authors: Montero P. , Bernis C. , Fernandez V. , Castro S.
Published: July 2008

Using a cross-sectional sample of 1147 urban adolescents, aged between 14 and 20 years, the variability of some menstrual cycle indicators was related to weight loss. Nearly 40% of the adolescents tried to lose weight and the results showed that attempting to lose weight is significantly associated with increased prevalence of menstrual irregularity and menstrual pain. This finding is independent of body mass index.
Sociodemographic risk factors associated with low birthweight in United Arab Emirates
Authors: Bener A. , Abdulrazzaq Y. M. , Dawodu A.
Published: July 2008

This case-control study was undertaken to determine socio-demographic risk factors for low birth weight in Al-Ain (United Arab Emirates) over a 12-month period in 1992–93. A total of 3485 live births occurred of which 293 (8·4%) were low birth weight. The risk factors considered were mother's occupation, house conditions, place of residence (urban or rural), maternal smoking habits, antenatal care, availability of help in the home, maternal BMI and educational status. Multiple logistic regression analysis showed that mother's occupation, maternal smoking, antenatal care, and lack of help in the home were associated with increased risk of low birth weight.
Galton Lecture: Behaviour genetic studies of intelligence, yesterday and today: the long journey from plausibility to proof
Authors: Bouchard Thomas J.
Published: July 2008

When asked whether he would discuss man in theOrigins of the Species, Darwin replied, ‘I think I shall avoid the subject, as so surrounded with prejudices, though I fully admit it is the highest and most interesting problem for the naturalist’. Galton on the other hand replied to the same question, ‘I shall treat man and see what the theory of heredity of variations and the principles of natural selection mean when applied to man’ (Pearson, 1914–30, Vol. II, p. 86).
Stress and age at menarche of mothers and daughters
Authors: Campbell Benjamin C. , Udry J. Richard
Published: July 2008

The hypothesis that psychological stress during early childhood leads to advanced reproductive maturation was assessed using data from the California Childhood Health and Development Study. Regression analyses failed to indicate that bed wetting, nightmares or thumb-sucking at age 5 predict age at menarche, regardless of controls for mother's age at menarche. Among socioeconomic variables suggested as contextual stressors measured at age 9–11 only mother's education was a significant predictor of daughter's age at menarche, though its effect is trivial compared to mother's age at menarche. Path analysis on a subsample of the subjects failed to demonstrate the hypothesised indirect effect of mother's age at menarche on daughter's age at menarche acting through early marriage and marital dissolution. These results cast doubt on the theory that early childhood stress is the key to divergent reproductive strategies among females based on the timing of reproductive maturation.
Coital frequency among married and cohabiting couples in the United States
Authors: Rao K. V. , Demaris Alfred
Published: July 2008

Coital frequency is studied among couples as a function of marital or cohabiting status, relationship duration, number of children, religious affiliation, income, education, fertility intentions, age, race, self-assessed health, time spent in work, and perceived relationship quality. Data are from the 1987–88 National Survey of Families and Households. Predictors of coital frequency that were stable across several analyses were male's and female's ages, the duration of the relationship, and the male partner's self-assessed health. When the discrepancy in partners' reports was adjusted, cohabitation status, number of children, future fertility intentions, religious affiliation, and relationship quality as assessed by the female partner were significant. The results suggest a substantial idiosyncratic component to the determination of coital frequency in relationships.
Ethnicity and obstetric performance in Singapore
Authors: Viegas O. A. C. , Leong W. P. , Chia Y. T. , Yeoh S. C. , Ratnam S. S.
Published: July 2008

The influence of ethnicity on obstetric performance in Singapore was assessed by retrospective analysis of all deliveries in the National University Hospital over a 7-year period. Malay mothers were younger, shorter, less educated, of higher parity, were more likely to have had no antenatal care, and had the highest incidence of premature labour. However, mothers of Indian origin had the smallest babies, the highest incidence of low birth weight and significantly higher perinatal mortality rates. Chinese mothers fared better than their Malay and Indian counterparts in all parameters assessed. The ethnic origin of the mother has an important bearing on perinatal performance. This emphasises the importance of designing appropriate strategies to improve perinatal health in the different ethnic groups.
Dimensions of occupations: genetic and environmental influences
Authors: Lichtenstein Paul , Hershberger Scott L. , Pedersen Nancy L.
Published: July 2008

This study investigates the dimensions of occupation, and distances between occupational categories, by using intra-pair differences in adult occupational position for identical twins reared apart. Status and farm dimensions of occupation were identified. The results validate the use of occupational status as a dimension of occupational position. The causes of individual differences for the derived status dimension were also evaluated, based on groups of identical and fraternal twins reared apart or together. Genetic effects accounted for a substantial amount of the variance in occupational status for men, while shared and non-shared environmental effects were of about equal importance. For women, genetic effects were less important, and shared and non-shared environmental effects accounted for more of the variation. The results confirm that genetic effects are important sources of the familial resemblance often found for occupational status for men.
Influence of industrialisation on marital behaviour in Beduído (Estarreja), Portugal
Authors: Padez Cristina , Abade Augusto
Published: July 2008

From marriage records of a Northern Portuguese parish for 1900–80, endogamy and exogamy rates were calculated for birthplace and residence in order to analyse the effect of industrialisation on the population structure after 1940. Marriages that were endogamous relative to birthplace decreased between 1940–49 (58·9%) and 1988 (20·5%), while exogamy increased. Exogamous marriages in which people came from outside the municipality (51·92%) were greater than those of the surrounding region (42·04%). After industrialisation, the pattern of marriages changed for residence, with an increase in the number of individuals who came from the district to work in the factories and married. Industrialisation advanced the start of exogamy which, for most Portuguese populations, began later, in the 1960s.
Significance of beliefs and values in predicting fertility and contraceptive behaviour in Pakistan
Authors: Zafar M. I. , Ford N. , Ankomah A.
Published: July 2008

A comparative study of 1100 women aged 25–45 years, users and non-users of modern methods of contraception, in the urban centres of Lahore and Faisalabad was conducted in 1991. The objective of the study was to investigate reproductive behaviour and the extent to which social, cultural and attitudinal variables, such as beliefs and values about family life, religiosity and fatalism, influence the fertility decision-making process. Preferences for smaller families were found to be consistently associated with modern attitudes and behaviour towards family and religious values and obligations. Family income, husband's occupation and religiosity offered no explanation of reproductive behaviour. It is concluded that cultural setting and tradition exert an important influence on reproductive behaviour, independent of economic development.
Early marriage among rural and urban females of South India
Authors: Sivaram M. , Richard J. , Rao P. S. S.
Published: July 2008

Data on 2972 marriages in rural areas and 1180 marriages in urban areas of North Arcot Ambedkar district of South India, during 1982–88, were analysed. The mean age at marriage of females was 18·6 in the rural and 19·6 in the urban area. The proportion of females married before attaining the legal age of 18 years was higher among the rural community (36·8%) than in the urban community (28·9%). Univariate analysis revealed an association between early age at marriage and the socioeconomic variables religion, caste, consanguinity, marital distance, spousal age difference, education and occupation of both bride and bridegroom, and socioeconomic status of the family. Multivariate analysis showed an independent relationship of marital distance and bridegroom's occupation with early age at marriage of females in the rural area alone and the bridegroom's education in the urban area alone. Consanguinity, spousal age difference and bride's education were found to be independently related with early age at marriage of females in both rural and urban areas.
Effects of inbreeding on marriage payment in North India
Authors: Badaruddoza  , Afzal M.
Published: July 2008

This study examines the relationships between consanguineous marriages and marriage payment, using data from two Muslim qaums living in urban and rural areas in Aligarh District, Uttar Pradesh, North India. Qaum and locality were found to have no significant association with the dowry system. Marriage payment is less common in consanguineous than in non-consanguineous marriages. However, the association between marriage payment and the type of marriage is significant at p<0·001. The dowry system is more prevalent among the higher socioeconomic groups, while the bride-wealth system is more common among the lower socioeconomic groups.
Factors affecting choice of sterilisation among low income women in Paraíba, Brazil
Authors: Rodrigues José , Moji Kazuhiko
Published: July 2008

Despite the absence of a family planning programme, the prevalence of sterilisation in Brazil has increased substantially, such that it is used by relatively young women in poor areas of the country. Sterilisation is influenced more by the characteristics of the health service than by socioeconomic characteristics of the population.
Androgen effects on women's gendered behaviour
Authors: Udry J. Richard , Morris Naomi M. , Kovenock Judith
Published: July 2008

Test of the applicability of the hormonal theory of sex-dimorphic behaviour to adult women is achieved in this study by assembling measures of prenatal and adult androgen exposure, and a broad measure of gendered behaviour on a sample of white women aged 27–30. Androgen exposure in the second (and no other) trimester of fetal life, combined with and in interaction with adult androgens, masculinises women's behaviour and explains a substantial proportion of the within-sex variance in women's adult gendered behaviour.
Birth intervals regarding infant mortality and extramarital reproduction in a Spanish rural community
Authors: Fuster V. , Jiménez A. , Morales B.
Published: July 2008

Record linking provided information on the complete reproductive schedules of a sample of 1102 couples with at least two children born alive from a rural Spanish community characterised by very high extramarital reproduction. Birth spacing was analysed considering final family size as well as the legitimate–illegitimate status and sex of the newborn, and survival of the preceding sibling.
Subsequent pregnancy affects morbidity of previous child
Authors: Bøhler Erik , Bergström Staffan
Published: July 2008

A prospective study of 113 children in rural Bhutan registered their morbidity and weight and their mothers' subsequent pregnancies, monthly for 32 months during the children's first 3 years of life. Children whose mothers had a subsequent birth interval of 18–30 months had an incidence of diarrhoea during the subsequent pregnancy 50% higher than their matched cohort whose mothers did not become pregnant (p=0·02). The relative risk for diarrhoea calculated from pooled child months was 1·51. Children whose mothers became pregnant also tended to have a higher incidence of skin infections.

Children, whose mothers were pregnant when they terminated breastfeeding, experienced an increased incidence of diarrhoea around weaning (p=0·01). Children weaned at the same age from non-pregnant mothers did not show increased morbidity.

This study, for the first time, relates observations of children's morbidity directly in time to the occurrence of the mother's subsequent pregnancy, and provides evidence of a causal relationship between a moderately short subsequent birth interval and a concurrent increase in morbidity for the study child.
Birth, marriage and death in illegitimacy: a study in northern Portugal
Authors: Abade Augusto , Bertranpetit Jaume
Published: July 2008

In populations in which the frequency of illegitimacy is high, illegitimates and legitimates may be subjected to different demographic and social pressures, with social and genetic consequences. A rural population from north-east Portugal is studied and variables from birth, marriage and death records are compared according to the legitimacy of the individuals. The analysis shows important differential demographic patterns in infant and child mortality and in migration prior to and related to marriage, especially in women. Some changes over time and gender differences are also evident.
Sleep habits and psychosomatic health complaints of bank workers in a megacity in Japan
Authors: Motohashi Yutaka , Takano Takehito
Published: July 2008

The relationship between sleep habits and psychosomatic health complaints was investigated by a questionnaire study in 148 bank workers in Tokyo. Daily bedtime was more flexible than daily rising time, and both mean bedtime and rising time tended to be earlier with increasing age. Multiple logistic regression analysis showed that psychosomatic health complaints of sleep disturbances, fatigue, digestive troubles, and depressive mood were significantly associated with sleep habits and perceived mental stress.
Childlessness and Marital Instability: A Re-Examination of the Evidence
Authors: Gibson Colin
Published: July 2008

Earlier studies have queried whether divorce was associated with childlessness. Evidence from surveys of broken marriages passing through the divorce courts of England and Wales indicates that infertility and divorce are not related in the way supposed. When the duration of de facto marriage is controlled, divorcing couples have a higher rate of fertility than that found within those who remain married. The former are also more likely to have a larger family size within the same period of time. Similar findings emerge from data relating to broken marriages resorting to the magistrates' courts. These results are partly a consequence of the trend whereby working-class marriages—with their earlier start of a family and larger completed family size—form an increasing proportion of all divorcing couples.

Survey results showed that within a divorcing population a shorter period of cohabitation resulted in a higher level of infertility. High infertility rates were also associated with later age at marriage and high social class. Current trends suggest that an increasing proportion of divorcing couples will be childless. It is concluded that there is need for a deeper knowledge of possible relationships, and their causes, in this and other areas of married life.
Implication of a Time-Dependent Model of Sexual Intercourse within the Menstrual Cycle
Authors: Dobbins J. G.
Published: July 2008

A time-dependent model of the probability of sexual intercourse, where the probability increases as the time from last intercourse increases, can produce waves in the expected frequency of sexual intercourse on the various dates of the menstrual cycle. These waves occur when the time-dependent model is linked with a period of abstinence, such as is usually found in most societies during the time of the menses. Previously, such waves have been attributed to cyclic hormonal changes in women without considering the full implication of a time-dependent model of sexual intercourse.
Decline in Coital Rates with Spouses' Ages and Duration of Marriage
Authors: James William H.
Published: July 2008

Cross-sectional and longitudinal study of a large sample confirms that mean marital coital rates decline very rapidly over the first year of marriage. They seem to halve over the first year of marriage, and then they take perhaps another 20 years to halve again. This pattern of decline is interpreted as evidence against the suggestion that coital rates are closely related to female hormone levels.

The higher correlation of marital coital rates with wife's age than with husband's age, it is argued here, is because wife's age is more closely associated than husband's age with duration of marriage (here seen as the most important of these three variables in the determination of coital rates). This is because of the substantially smaller variance of wife's age at marriage than husband's age at marriage.
Attitudes of Persons at Risk for Fabry's Disease Towards Predictive Tests and Genetic Counselling
Authors: Sørensen S. A. , Hasholt Lis
Published: July 2008

Adult members of a kindred with various cases of Fabry's disease were asked by questionnaire about their attitudes and behaviour towards prospective genetic counselling. All individuals were aware of the fact that the disease occurred in their family and that it is hereditary, but none had a correct understanding of its inheritance. The disease was considered to be severe and the general attitude was that it should be prevented. Elective abortion after prenatal diagnosis was recommended by the majority, but some would prefer to abstain from having children. Prospective counselling was received positively even though it provoked anxiety in some of the counselled persons. The counselling has so far had the result that two heterozygous females asked for prenatal investigation. But when affected male fetuses were detected after prenatal diagnosis abortion was rejected in both cases. The reasons for this were not considered to be typical. It is concluded that prospective genetic counselling for Fabry's disease should be offered to other families, even though it may be expected that some will choose not to prevent further cases.
Stability of a stratified fluid with a vertically moving sidewall
Authors: BLANCHETTE FRANÇOIS , PEACOCK THOMAS , COUSIN RÉMI
Published: July 2008

We present the results of a combined theoretical and experimental study of the stability of a uniformly stratified fluid bounded by a sidewall moving vertically with constant velocity. This arrangement is perhaps the simplest in which boundary effects can drive instability and, potentially, layering in a stratified fluid. Our investigations reveal that for a given stratification and diffusivity of the stratifying agent, the sidewall boundary-layer flow becomes linearly unstable when the wall velocity exceeds a critical value. The onset of instability is clearly observed in the experiments, and there is good quantitative agreement with some predictions of the linear stability analysis.
Non-normal stability analysis of a shear current under surface gravity waves
Authors: AMBROSI D. , ONORATO M.
Published: July 2008

The stability of a horizontal shear current under surface gravity waves is investigated on the basis of the Rayleigh equation. As the differential operator is non-normal, a standard modal analysis is not effective in capturing the transient growth of a perturbation. The representation of the stream function by a suitable basis of bi-orthogonal eigenfunctions allows one to determine the maximum growth rate of a perturbation. It turns out that, in the considered range of parameters, such a growth rate can be two orders of magnitude larger than the maximum eigenvalue obtained by standard modal analysis.
Linear perturbation response of self-similar ablative flows relevant to inertial confinement fusion
Authors: CLARISSE J.-M. , BOUDESOCQUE-DUBOIS C. , GAUTHIER S.
Published: July 2008

A family of exact similarity solutions for inviscid compressible ablative flows in slab symmetry with nonlinear heat conduction is proposed for studying unsteadiness and compressibility effects on the hydrodynamic stability of ablation fronts relevant to inertial confinement fusion. Dynamical multi-domain Chebyshev spectral methods are employed for computing both the similarity solution and its time-dependent linear perturbations. This approach has been exploited to analyse the linear stability properties of two self-similar ablative configurations subjected to direct laser illumination asymmetries. Linear perturbation temporal and reduced responses are analysed, evidencing a maximum instability for illumination asymmetries of zero transverse wavenumber as well as three distinct regimes of ablation-front distortion evolution, and emphasizing the importance of the mean flow unsteadiness, compressibility and stratification.
Laws for third-order moments in homogeneous anisotropic incompressible magnetohydrodynamic turbulence
Authors: PODESTA J. J.
Published: July 2008

It is known that Kolmogorov's four-fifths law for statistically homogeneous and isotropic turbulence can be generalized to anisotropic turbulence. This fundamental result for homogeneous anisotropic turbulence says that in the inertial range the divergence of the vector third-order moment 〈|δv(r)|2δv(r)〉 is constant and is equal to -4ϵ, where ϵ is the dissipation rate of the turbulence. This law can be extended to incompressible magnetohydrodyamic (MHD) turbulence where statistical isotropy is often not valid due, for example, to the presence of a large-scale magnetic field. Laws for anisotropic incompressible MHD turbulence were first derived by Politano and Pouquet. In this paper, the laws for vector third-order moments in homogeneous non-isotropic incompressible MHD turbulence are derived by a technique due to Frisch that clarifies the relationship between the energy flux in Fourier space and the vector third-order moments in physical space. This derivation is different from the original derivation of Politano and Pouquet which is based on the Kármán–Howarth equation, and provides some new physical insights. Separate laws are derived for the cascades of energy, cross-helicity and magnetic-helicity, the three ideal invariants of incompressible MHD for flows in three dimensions. These laws are of fundamental importance in the theory of MHD turbulence where non-isotropic turbulence is much more prevalent than isotropic turbulence.
A geophysical-scale model of vertical natural convection boundary layers
Authors: WELLS ANDREW J. , WORSTER M. GRAE
Published: July 2008

A model is developed for turbulent natural convection in boundary layers formed next to isothermal vertical surfaces. A scaling analysis shows that the flow can be described by plume equations for an outer turbulent region coupled to a resolved near-wall laminar flow. On the laboratory scale, the inner layer is dominated by its own buoyancy and the Nusselt number scales as the one-third power of the Rayleigh number (Nu ∝ ${\it Ra}_z^{1/3}$). This gives a constant heat flux, consistent with previous experimental and theoretical studies. On larger geophysical scales the buoyancy is strongest in the outer layer and the laminar layer is driven by the shear imposed on it. The predicted heat transfer correlation then has the Nusselt number proportional to the one-half power of Rayleigh number (Nu ∝ ${\it Ra}_z^{1/2}$) so that a larger heat flux is predicted than might be expected from an extrapolation of laboratory-scale results. The criteria for transitions between flow regimes are consistent with a hierarchy of instabilities of the near-wall laminar flow, with a buoyancy-driven instability operating on the laboratory scale and a shear-driven instability operating on geophysical scales.
The viscous catenary revisited: experiments and theory
Authors: KOULAKIS JOHN P. , MITESCU CATALIN D. , BROCHARD-WYART FRANÇOISE , DE GENNES PIERRE-GILLES , GUYON ETIENNE
Published: July 2008

Detailed observations have been performed on the evolution of a viscous catenary, a rope of high-viscosity fluid suspended from two points falling under gravity. Stroboscopic imaging techniques are used to obtain the position and shape of the strand as a function of time. Depending on their initial thickness and profile, the filaments are observed to evolve into either a quasi-catenary, or other, more complex shapes. A conceptually simple, energy-based theory is developed and compared with observations. It is shown to describe reasonably, except for a scaling in the time scale, the catenary-like regime.
Mixing of two thermal fields emitted from line sources in turbulent channel flow
Authors: COSTA-PATRY E. , MYDLARSKI L.
Published: July 2008

The interaction of two passive scalars (both temperature in air) emitted from concentrated line sources in fully developed high-aspect-ratio turbulent channel flow is studied. The thermal fields are measured using cold-wire thermometry in a flow with a Reynolds number (Uh/ν) of 10200.

The transverse total root-mean-square (RMS) temperature profiles are a function of the separation distance between the line sources (d/h), their average wall-normal position (ysav/h), and the downstream location (x/h), measured relative to the line sources. Similarly, profiles of the non-dimensional form of the scalar covariance, the correlation coefficient (ρ), are a function of the same parameters and quantify the mixing of the two scalars.

The transverse profiles of the correlation coefficient are generally largest at the edges of the thermal plume and smallest in its core. When the line sources are not symmetrically located about the channel centreline, the minimum in the correlation coefficient transverse profiles drifts towards the (closer) channel wall. For source locations that are equidistant from the channel centreline, the minimum correlation coefficient occurs at the centreline, due to the underlying symmetry of this geometry. The initial downstream evolution of the correlation coefficient depends significantly on d/h, similar to that in homogeneous turbulence. However, there is always a dependence on ysav/h, which increases in importance as both the downstream distance is increased and the wall is approached. Lastly, the correlation coefficient profiles tend towards positive values in the limit of large downstream distances (relative to the source separation), though further measurements farther downstream are required to confirm the exact value(s) of their asymptotic limit(s).

Spectral analysis of the cospectra and coherency spectra indicates that the large scales evolve more rapidly than the small ones. Furthermore, the fast evolution of the large scales was most evident when the sources were located close to the wall. This presumably derives from the large-scale nature of turbulence production, which is strong in the near-wall region.
Buoyancy-driven motion of a gas bubble through viscous liquid in a round tube
Authors: FENG JAMES Q.
Published: July 2008

The steady axisymmetric flow of viscous liquid relative to a gas bubble due to its buoyancy-driven motion in a round tube is computed by solving the nonlinear Navier–Stokes equations using a Galerkin finite-element method with a boundary-fitted mesh. When the bubble is relatively small compared with the tube size (e.g. the volume-equivalent radius of the bubble is less than a quarter of the tube radius R), the bubble exhibits similar behaviour to one moving in an extended liquid, developing a spherical-cap shape with increasing Reynolds number (Re) if the capillary number is not too small. The long-bubble (also known as a Taylor bubble) characteristics can be observed with bubbles of volume-equivalent radius greater than the tube radius, especially when the surface tension effect is relatively weak (e.g. for Weber number We greater than unity). The computed values of Froude number Fr for most cases agree well with the correlation formulae derived from experimental data for long bubbles, and even with (short) bubbles of volume-equivalent radius three-quarters of the tube radius. All of the computed surface profiles of long bubbles exhibit a prolate-like nose shape, yet various tail shapes can be obtained by adjusting the parameter values of Re and We. At large Weber number (e.g. We=10), the bubble tail forms a concave profile with a gas ‘cup’ developed at small Re and a ‘skirt’ at large Re with sharply curved rims. For We≤1, the bubble tail profile appears rounded without large local curvatures, although a slightly concave tail may develop at large Re. non-uniform annular film adjacent to the tube wall is commonly observed when Weber number is small, especially for bubbles of volume <3πR3, suggesting that the surface tension effect can play a complicated role. Nonetheless the computed value of Fr is found to be generally independent of the bubble length for bubbles of volume-equivalent radius greater than the tube radius. If the bubble length reaches about 2.5 tube radii, the value of its frontal radius becomes basically the same as that for long bubbles of much larger volume. An examination of the distribution of the z-component of traction along the bubble surface reveals the basic mechanism for long bubbles rising at a terminal velocity that is independent of bubble volume.
The effect of a lifted flame on the stability of round fuel jets
Authors: NICHOLS JOSEPH W. , SCHMID PETER J.
Published: July 2008

The stability and dynamics of an axisymmetric lifted flame are studied by means of direct numerical simulation (DNS) and linear stability analysis of the reacting low-Mach-number equations. For light fuels (such as non-premixed methane/air flames), the non-reacting premixing zone upstream of the lifted flame base contains a pocket of absolute instability supporting self-sustaining oscillations, causing flame flicker even in the absence of gravity. The liftoff heights of the unsteady flames are lower than their steady counterparts (obtained by the method of selective frequency damping (SFD)), owing to premixed flame propagation during a portion of each cycle. From local stability analysis, the lifted flame is found to have a significant stabilizing influence at and just upstream of the flame base, which can truncate the pocket of absolute instability. For sufficiently low liftoff heights, the truncated pocket of absolute instability can no longer support self-sustaining oscillations, and the flow is rendered globally stable.
Lymphangiomatosis: a differential diagnosis of lytic lesions of the temporal bone
Authors: Naguib M B , Al-Jazan N , Hashem T
Published: July 2008

Objective:

We report a histologically proved case of lymphangiomatosis of the skull, involving the temporal bone and presenting as multiple lytic bone lesions.

Method:

A case report and a review of the literature concerning lymphangiomatosis are presented.

Results:

Lymphangiomatosis affecting bones is a rare disorder caused by a congenital malformation of the lymphatic system, resulting in diffuse proliferation of the lymphatic channels and involving bones, parenchymal organs and soft tissue. Involved bones show massive osteolysis and progressive, localised bone resorption.

Conclusion:

Lymphangiomatosis should be kept in mind in the differential diagnosis of lytic lesions of the skull.
High-yield amplification ofCryptosporidium parvumin interferon γ receptor knockout mice
Authors: von OETTINGEN J. , NATH-CHOWDHURY M. , WARD B. J. , RODLOFF A. C. , ARROWOOD M. J. , NDAO M.
Published: July 2008

To date, large-scale production ofCryptosporidium parvumoocysts has only been achieved by amplification in neonatal calves and sheep. Many laboratories currently depend on supplies from external sources and store oocysts for prolonged periods which results in progressive loss of viability. Six to 8-week-old interferon γ receptor knockout (IFNγR-KO) mice on a C57BL/6 background were inoculated by gavage (2000 oocysts/animal). Fecal pellets were collected daily from 7 days post-infection (p.i.) up to 2 weeks p.i. Intestinal oocyst yield was assessed at days 11, 12 and 14 p.i. by homogenization of intestinal tissues. Ether extraction and one or more NaCl flotations were used to purify oocysts. Total recoveries averaged 2·6×106oocysts/mouse from fecal material and 3·8×107oocysts/mouse from intestinal tissues. Overall, 2·3×109purified oocysts were obtained from 60 mice. Recovered oocysts were capable of sporulation and were shown to be infectious bothin vitroandin vivo. Oocyst amplification was achieved in only 11–14 days with minimal expense. The simplicity of this method presents a practical alternative for the routine passage, maintenance and storage ofC. parvumin biomedical laboratories.
Foodborne outbreak of gastroenteritis due to Norovirus and Vibrio parahaemolyticus
Authors: SALA M. R. , ARIAS C. , DOMÍNGUEZ A. , BARTOLOMÉ R. , MUNTADA J. M.
Published: July 2008

Vibrio parahaemolyticus and Norovirus have been recognized as the cause of sporadic cases or outbreaks of diarrhoeal illness in association with the ingestion of raw or improperly cooked seafood. This report describes a foodborne outbreak of gastroenteritis caused by both Norovirus and Vibrio parahaemolyticus following the consumption of raw seafood in a restaurant in Terrassa (Catalonia, Spain) in September 2005. Measures are needed to reduce contamination of raw seafood. Consumers can reduce the risk of foodborne illness by avoiding consumption of raw or undercooked food.
FIFA World Cup 2006 in Germany: enhanced surveillance improved timeliness and detection
Authors: WILLIAMS C. J. , SCHENKEL K. , ECKMANNS T. , ALTMANN D. , KRAUSE G.
Published: July 2008

Enhanced surveillance for infectious disease events, with accelerated routine reporting and daily supplementary reports, was undertaken during the 2006 FIFA World Cup in Germany. We evaluated the surveillance outputs, reporting intervals and detection of World Cup-relevant events for the enhanced system. Outbreak numbers for measles, Norovirus and Campylobacter were significantly higher than in previous years, but all increases were explained by prior trends. The median interval (disease onset to receipt at national centre) fell from 17 days in 2005 to 12 days in 2006. Detection of World Cup-relevant events was 44% (8/18) in the routine system and 77% (14/18) in supplementary reports. We did not identify any significant effect on infectious disease epidemiology relating to the FIFA 2006 World Cup. Daily reporting improved timeliness, and supplementary reporting improved relevant event detection. Enhancing existing systems, without the addition of syndromic surveillance, can be an effective approach to mass-event surveillance.
Varicella paediatric hospitalizations in Spain
Authors: GUILLÉN J. M. , SAMANIEGO-COLMENERO M. DE LA LUZ , HERNÁNDEZ-BARRERA V. , GIL A.
Published: July 2008

Varicella is a very common childhood disease responsible for an important number of hospitalizations every year in Spain. The aim of this study was to assess the burden of chickenpox hospitalizations in Spain in the 7-year period between 1999 and 2005. Data of hospital discharges relating to varicella were obtained from the Conjunto Mínimo Básico de Datos (CMBD), the Spanish surveillance system for hospital data. All paediatric hospitalizations for primary varicella that occurred between 1 January 1999 and 31 December 2005 were selected. The hospitalization rate for the 7-year study period was 23·06 hospitalizations/100 000 population. The highest incidences of hospitalizations were observed in the youngest groups (60·79 and 55·65/100 000 population for ages 0–12 months and 1–2 years respectively). Nineteen deaths were reported during the study period. The median length of stay in hospital was 4 days (interquartile range 3–7 days). Despite the availability of effective varicella vaccines, chickenpox remains an important cause of hospitalizations in Spain.
Use of antibiotics and risk factors for carriage ofStreptococcus pneumoniae: a longitudinal household study in the United Kingdom
Authors: PEBODY R. G. , MORGAN O. , CHOI Y. , GEORGE R. , HUSSAIN M. , ANDREWS N.
Published: July 2008

This study aimed to identify risk factors and assess the impact of coincidental antibiotic therapy on carriage ofStreptococcus pneumoniae. Index children from birth to 3 years and their households were recruited from primary health-care registers in four UK general practices. Nasopharyngeal swabs were taken monthly from study participants ten times between October 2001 and July 2002. Multilevel random-effect models were used to adjust for statistical dependence between repeated measurements and family clustering of carriage. Carriage results were available for 3753 swabs from 489 individuals in 121 families. Crude prevalence of carriage was 25%. On multivariable analysis, risk of carriage was reduced by antibiotic use the previous month [odds ratio (OR) 0·34, 95% confidence interval (CI) 0·22–0·52], but increased if a child attended day care for >20 h per week (OR 2·52, 95% CI 1·41–4·52). Taking antibiotics significantly reduces the risk of carriage the following month in a setting with a low prevalence of pneumococcal antimicrobial resistance.
Recognizable languages in divisibility monoids
Authors: DROSTE MANFRED , KUSKE DIETRICH
Published: July 2008

We define the class of divisibility monoids that arise as quotients of the free monoid Σ*

modulo certain equations of the form ab = cd. These form a much larger class than free

partially commutative monoids, and we show, under certain assumptions, that the

recognizable languages in these divisibility monoids coincide with c-rational languages. The

proofs rely on Ramsey's theorem, distributive lattice theory and on Hashigushi's rank

function generalized to these monoids. We obtain Ochmański's theorem on recognizable

languages in free partially commutative monoids as a consequence.
On the elimination of some higher type quantifiers
Authors: IKEDA YASUWO , TOMITA KOHJI , HOSONO CHIHARU
Published: July 2008

This paper concerns the elimination of higher type quantifiers and gives two theorems. The
first theorem shows that quantifiers in formulae of a specific form can be eliminated. The
second theorem shows that quantifiers in formulae of a similar form cannot be eliminated,
that is, such formulae do not have an equivalent first-order formula. The proof is based on
the Ehrenfeucht game. These theorems are important for design of an interpreter of a ν act,
which is a representation of mathematical action. Moreover, even if the universe is assumed
to be finite, these theorems hold.
Environmental economics in poor countries: the current state and a programme for improvement
Authors: Dasgupta Partha , Mäler Karl-Göran
Published: July 2008

People in poor countries are for the most part agrarian and pastoral. In 1988 rural people accounted for about 65 per cent of the population of what the World Bank classifies as low-income countries. The proportion of the total labour force in agriculture was a bit in excess of this. The share of agriculture in gross domestic product in these countries was 30 per cent. These figures should be contrasted with those from industrial market economies, which are 6 per cent and 2 per cent for the latter two ratios, respectively.