Past pandemics and climate variability across the Mediterranean.

The influence that meteorological, climatological and environmental factors had on historical disease outbreaks is often speculated upon, but little investigated. Here, we explore potential associations between pandemic disease and climate over the last 2,500 years in Mediterranean history, focusing on ancient disease outbreaks and the Justinianic plague in particular. We underscore variation in the quality, quantity and interpretation of written evidence and proxy information from natural archives, the comlexity of identifying and disentangling past climatological and environmental drivers, and the need to integrate diverse methodologies to discern past climate-disease linkages and leverage historical experiences to prepare for the rapid expansion of novel pathogenic diseases. Although the difficulties entailed in establishing historical climate-pandemic linkages persist to the present, this is a research area as urgent as it is complex and historical perspectives are desperately needed.

Contributions of Particle Image Velocimetry to Helicopter Aerodynamics: A Review.

The advancement of flow measurement techniques continues to extend experimental boundaries and thus significantly contributes to improving our understanding of both basic and applied aerodynamics. This is particularly apparent in the case of particle image velocimetry (PIV), where its application has furthered the existing knowledge in several areas of helicopter rotor aerodynamics. The complex nature of helicopter rotor flows presents unique challenges to experimentalists, including transonic flow, concentrated vortices and dynamic stall. To illustrate the impact of the technological advancements on the way helicopter aerodynamics is studied today, the development of PIV since the early nineties of the last century is reviewed and some recent PIV applications are described. Using examples of main rotor wakes, dynamic stall and flow control investigations, the capabilities of large-scale, time-resolved and volumetric PIV are summarized.

Ethnic differences in skin physiology, hair follicle morphology and follicular penetration.

BACKGROUND/AIMS: Inconsistent evidence is available that different ethnic groups exhibit differences in skin physiological parameters. Recently, variations in hair follicle morphology have been described, although the influence of such variations on the follicular penetration process has not been investigated until now. METHODS: The aim of the present study was thus to investigate skin physiological parameters, follicle morphology and the penetration process in different ethnic groups. RESULTS AND CONCLUSION: Whereas no significant differences with regard to skin physiological parameters could be observed, morphological analysis of the hair follicles revealed, inter alia, that Caucasians had significantly larger terminal hair follicles than Asians and Africans. The surface of the hair follicle infundibulum was shown to be 3% in Caucasians, 2.6% in Africans and 2.4% in Asians. The investigations into penetration revealed no significant differences after a 30-min penetration time, whereas after 24 h, the Asian volunteers presented significantly larger amounts of sodium fluorescein in the hair follicles and the stratum corneum, which may be explained by cultural habits.

Neuronavigation in the minimally invasive presacral approach for lumbosacral fusion.

INTRODUCTION: Intraoperative 3D navigation (3D NAV) is gaining importance in spinal surgery, especially with the advancement of minimally invasive techniques in this field. We hypothesized that 3D NAV may be of benefit in the recently described minimally invasive presacral approach for L4-S1 fusion (AxiaLIF). METHODS: Five patients with refractory low back pain and L5-S1 degenerative disease underwent 3D NAV-assisted placement of a presacral L5-S1 screw. Additionally, a patient recently underwent a two-level AxiaLIF procedure (L4-S1) which was also performed with 3D NAV. Navigation was performed by acquiring intraoperative images via isocentric fluoroscopy and utilizing frameless stereotaxy. Accuracy of 3D NAV was confirmed by overlapping intraoperative images, navigation screenshots, and postoperative CT scans. Outcome was determined by pre- and postoperative VAS (back and leg pain) and ODI. RESULTS: Operative results were reviewed for all six patients and clinical outcomes were retrospectively reviewed for the five L5-S1 procedure patients. Postoperative imaging demonstrated accurate screw placement in comparison to intraoperative C-arm imaging and navigation imaging in all patients. No perioperative complications were encountered. In the five one-level patients, mean VAS (for back and leg pain) and ODI improved significantly at most recent follow-up. CONCLUSION: The minimally invasive presacral approach to L4-L5-S1 fusion can be performed safely and accurately with intraoperative 3D NAV. This is especially the case in two-level AxiaLIF procedures, where computer guidance can provide better planning possibilities for optimal screw trajectory.

Use of an isogenic mutant constructed in Moraxella catarrhalis To identify a protective epitope of outer membrane protein B1 defined by monoclonal antibody 11C6.

Moraxella catarrhalis-induced otitis media continues to be a significant cause of infection in young children, prompting increased efforts at identifying effective vaccine antigens. We have previously demonstrated that M. catarrhalis expresses specific outer membrane proteins (OMPs) in response to iron limitation and that this organism can utilize transferrin and lactoferrin for in vitro growth. One of these proteins, which binds human transferrin, is OMP B1. As the human host presents a naturally iron-limited environment, proteins, like OMP B1, which are expressed in response to this nutritional stress are potential vaccine antigens. In this study, we have developed monoclonal antibody (MAb) 11C6, which reacts to a surface-exposed epitope of OMP B1 expressed by M. catarrhalis 7169. This antibody was used to clone ompB1, and sequence analysis suggested that OMP B1 is the M. catarrhalis homologue to the transferrin binding protein B described for pathogenic Neisseriaceae, Haemophilus influenzae, Actinobacillus pleuropneumoniae, and M. catarrhalis. Expression of recombinant OMP B1 on the surface of Escherichia coli confers transferrin binding activity, confirming that this protein is likely involved in iron acquisition. In addition, ompB1 was used to construct an isogenic mutant in M. catarrhalis 7169. This mutant, termed 7169b12, was used as the control in bactericidal assays designed to determine if OMP B1 elicits protective antibodies. In the presence of MAb 11C6 and human complement, wild-type 7169 demonstrated a 99% decline in viability, whereas the ompB1 isogenic mutant was resistant to this bactericidal activity. Further analysis with MAb 11C6 revealed the presence of this OMP B1 epitope on 31% of the clinical isolates tested. These data suggest that OMP B1 is a potential vaccine antigen against M. catarrhalis infections.

Identifying children with high mortality risk.

PIP: This issue reports selected results from a comprehensive study of infant and child mortality based on the National Family Health Survey data. The analysis distinguishes between neonatal, postneonatal, infant and child mortality since mortality and its causes vary considerably among children of different ages. Hazard regression analysis was used to estimate the effects of each individual variable as the factors that affect infant and child mortality tend to be correlated with each other. The study involves adjusted effects of selected socioeconomic and demographic characteristics on neonatal, postneonatal, infant, and child mortality for children born during the survey. Short birth intervals have a great effect on infant and child mortality. A previous birth interval of less than 24 months increases child mortality by about 67%. Neonatal mortality is highest among children of very young mothers. Child mortality is higher for girls in all states except Tamil Nadu, Kerala, and Goa. Seven groups of children who are especially vulnerable to infant and child mortality were identified. Thus, intervention programs, such as efforts to provide supplemental nutrition and basic immunization to pregnant mothers, infants and young children need to focus on these high-risk groups. Results for many states show elevated mortality rates for girls after the neonatal period. Family health programs aimed at overall improvement in mortality levels should pay attention to providing basic health care and supplemental nutrition to girls.^ieng

Nepal survey shows that "family planning saves lives".

PIP: This article presents the results of the Nepal Family Health Survey (NFHS) conducted from January through June 1996. Data on fertility, family planning, and maternal and child health were collected from 8429 ever-married women aged 15-49 years. These women provided information on 29,156 children. Using the method of regression analysis, findings reveal those factors, such as young mothers, large families, and short birth intervals, substantially increase under-five mortality risks. However, socioeconomic factors have only a limited effect on under-five mortality. Statistics have suggested that much of the urban/rural differences in mortality have been due to factors closely related to residence, mother's level of education and economic status. In addition, although positive effects of interventions (antenatal and postpartum checkups, tetanus immunization and assistance at delivery by a traditional birth attendant) have been documented, statistical results show that few children in Nepal are receiving the benefits of maternal health care. In conclusion, results of the 1996 NFHS show that delaying, spacing, and limiting births can substantially reduce infant and child mortality.^ieng

Accelerating India's fertility decline: the role of temporary contraceptive methods.

PIP: This report summarizes findings from the 1992-93 National Family Health Survey of India, on fertility and contraceptive use. Fertility declined about 2 children/woman during 1972-92. The total fertility rate in 1992-93 was 3.4 children/woman. The average desired number of children among ever married women aged 13-49 years was 2.9 children/woman. Among the 41% of women who used contraception, 76% relied on sterilization. 27% of currently married women of reproductive age were sterilized, and 3% had husbands who were sterilized. 20% of women had an unmet need for family planning. 64% of all women currently using temporary methods wanted no more children. 11% desired more children after an interval of 2 or more years. 9% desired a stop to childbearing. Women not currently using contraception and intending to use in the future preferred sterilization (59%) or a temporary method (36%). Currently, 24% of contraceptive users rely on temporary methods. It is likely that meeting unmet need for temporary methods would substantially increase contraceptive use. Women who were not using any method averaged 2.7 children, while sterilized women had 4.0 children. Women who used traditional methods averaged 2.8 children. Women using temporary methods averaged 2.6 children. It is unlikely that sterilization would further reduce fertility much below levels already reached. Women sterilized before the age of 24 years tended to have modest sized families, but most women were sterilized at older ages. Currently, only 10% of married women use temporary methods, and only 6% use a modern method.^ieng

Mother's tetanus immunisation is associated not only with lower neonatal mortality but also with lower early-childhood mortality.

PIP: This article examines how neonatal and early childhood mortality varies according to the tetanus immunization of the mother. This study is based on the National Family Health Survey data. Findings showed that maternal tetanus immunization during pregnancy is recognized as almost sure protection against tetanus in the mother and the newborn child. Maternal tetanus immunization is viewed as a good indicator of the general health-seeking behavior of a mother. It could serve as a useful tool for program evaluation and policymaking. Public health education programs are designed to persuade women to be immunized against tetanus. Promotion of such behaviors might be incorporated into health education programs for women who have not been immunized.^ieng

Are fertility differentials by education converging in the United States?

"According to the theory of demographic transition, fertility differentials by education tend to become strongly negative in the early stages of transition, because family limitation tends to catch on first among the more educated. As the transition proceeds, contraceptive use diffuses to the less educated, and fertility differentials by education eventually tend to reconverge. The question addressed here is: Do fertility differentials by education disappear or become positive in advanced industrial societies? Evidence presented in this paper indicates that in the United States they do not. As late as 1990, the latest year that we consider, fertility differentials by education were still strongly negative." (SUMMARY IN ITA AND FRE)

Consistent correction of data for aboriginal populations.

"A consistent correction procedure is used to determine improved, consistent estimates by sex of census age distributions, intercensal births, intercensal deaths and net migration by age for the Aboriginal populations of the Northern Territory, South Australia and Western Australia during the period 1986-91. Undercount estimates and life tables show the Aboriginal populations to have lower coverage in statistical collections and much higher death risks than the total Australian population. Inter-regional net migration estimates show that component of change can no longer be ignored."

The parity structure of fertility decline in Thailand, 1953-1979.

PIP: Researchers fitted sample data on 15-65 year old women from the 1970 and 1980 censuses of Thailand to the model fertility curve of the extended birth history reconstruction procedure which looks at duration since 1st marriage specific fertility rates and age at marriage as the minimum age of women at conception. This study actually covered the period 1953-1979. Considerable underreporting of children ever born occurred in the 1980 census, but mainly among women of at least parity 5. This found a substantial decline in progression from parity 0 to parity 1 during the late 1960s and the 1970s. Further the period progression ratios from parity 0 to 1st marriage and 1st marriage to parity 1 fell with time, especially parity 0 to 1st marriage. During the study period, family size fell to mainly 2. Some families did complete family size at 3 children, however. The researchers observed that, in the 1980 census, 2299 women out of 43,848 reported own children born before the women married. This finding made the researches question the quality of the age data and/or the applicability of the extended procedure since it assumes no fertility before 1st marriage. They did no exclude these women, however, when the calculated the period progression ratios for progression from 1st marriage to parity 1 since that would introduce bias in the results. Thus the results for that progression would have not been parallel to those for the other progressions. In conclusion, the significant decline in the number of Thai women who had a 1st marriage and then a 1st birth between 1965-1979 contributed considerably to the fertility decline in Thailand.^ieng

Consistent correction of census and vital registration data.

A new procedure is developed for simultaneously and consistently correcting 2 or more censuses and intercensal registered births and deaths. The procedure begins with a set of preliminary correction factors, which are not necessarily consistent. It then uses the mathematics of finite-dimensional vector spaces to derive an optimal set of final consistent correction factors. The optimization procedure is based on the principle that there exists in a hyperplane a unique point of minimum distance from a fixed point not in the hyperplane. For purposes of illustration, the procedure is applied to the censuses of 1970, 1975, and 1980 and intercensal registered births and deaths for the periods 1970-1975 and 1975-1980 for the Republic of Korea.

Fitting age-specific fertility with the Makeham curve.

PIP: The Makeham curve has long been recognized for its empirically good fit of adult mortality experience. However, it has never been seriously used in fertility estimation. This paper aims to show that the Makeham curve provides a very good fit of cumulative age-specific fertility over the full range of the fertility experience. Presented here is a simple linearization procedure, easily executed by hand calcualtor, for the estimation of cumulative age-specific fertility per woman (or parity) ar exact age x. The procedure provides a check for the fit of the Makeham curve to cumulative age-specific fertility, locally or globally--that is, the fit to local ratios over any range of ages. The procedure also determines the parameters of optimum fit over any range of ages. To carry out the procedure, one must simply check the linearity of points in each of 2 data plots and determine the Makeham curve from the slopes and intercepts of the fitted straight lines. The mathematical methodology for the procedure is presented and the global goodness of fit studied. Because it is of a local nature, and since it elicits an explicit analytic formula for the fitted Makeham curve, the procedure is conducive to interpolation and extrapolation applications, including the completion of incomplete schedules of age-specific fertility rates at the tails of the reproductive age span. The use of the procedure for extrapolation purposes is illustrated with data from the 1968 Population Growth Survey of Pakistan. It suggests results that, for the most part, are consistent with the thesis of general age exaggeration of reporting women. However, further evidence is needed to be conclusive.^ieng

Measuring changes in census coverage in Asia.

PIP: A study of two successive censuses held prior to 1980 in seven Asian countries is used to examine whether census coverage has improved in recent times. The method used to determine the relative differences in coverage was developed from that originally suggested by Samuel Preston and Kenneth Hill. The study indicates that although census coverage improved slightly in Japan, it remained the same in Taiwan and the Republic of Korea and declined in India, Indonesia, the Philippines, and Thailand.^ieng

A simple linearization procedure for local fit of the Weibull survival distribution: a note on an article by Choe.

The author comments on an article by Choe concerning the use of the Weibull survival function to fit curves to infant and childhood mortality data. "As an alternative to the computer program [employed by Choe], this note gives a simple linearization procedure that is easily executed by hand calculator. This procedure allows one to check the fit of the Weibull curve locally...for a range of ages (e.g. those from which one wishes to extrapolate). It also provides a simple way to find the Weibull curve parameters of optimum local fit." The procedure is illustrated using data for the period 1970-1971 for males and females in Taiwan.