bluuebunny/crossref_metadata_2025 huggingface dataset:
Low temperature or GroEL/ES overproduction permits growth of Escherichia coli cells lacking trigger factor and DnaK
Authors: Vorderwülbecke S , Kramer G , Merz F , Kurz T.A , Rauch T , Zachmann-Brand B , Bukau B , Deuerling E
Published: January 2004

Escherichia coli trigger factor (TF) and DnaK cooperate in the folding of newly synthesized proteins. The combined deletion of the TF‐encoding tig gene and the dnaK gene causes protein aggregation and synthetic lethality at 30°C. Here we show that the synthetic lethality of ΔtigΔdnaK52 cells is abrogated either by growth below 30°C or by overproduction of GroEL/GroES. At 23°C ΔtigΔdnaK52 cells were viable and showed only minor protein aggregation. Overproduction of GroEL/GroES, but not of other chaperones, restored growth of ΔtigΔdnaK52 cells at 30°C and suppressed protein aggregation including proteins ≥60 kDa, which normally require TF and DnaK for folding. GroEL/GroES thus influences the folding of proteins previously identified as DnaK/TF substrates.
Characterization of CJ1293, a new UDP‐GlcNAc C6 dehydratase from Campylobacter jejuni1
Authors: Creuzenet Carole
Published: January 2004

Campylobacter jejuni encodes numerous sugar‐nucleotide‐modifying enzymes potentially involved in the biosynthesis of surface carbohydrates. One of them, CJ1293, is involved in flagellin glycosylation but its biochemical activity remains unknown. Using over‐expressed and purified protein, we demonstrate that CJ1293 has UDP‐GlcNAc‐specific C6 dehydratase activity. Catalysis occurs without addition of cofactor, suggesting internal recycling of NAD(P)+. The K
m for UDP‐GlcNAc of 50 μM indicates that CJ1293 has higher affinity for its substrate than previously characterized homologues. Based on enzymatic data, we propose that CJ1293 catalyzes the first step in the biosynthesis of bacillosamine, a sugar found in C. jejuni's protein glycosylation motifs.
Structural features of transmembrane helices
Authors: Hildebrand Peter Werner , Preissner Robert , Frömmel Cornelius
Published: January 2004

A total of 160 transmembrane helices of 15 non‐homologous high‐resolution X‐ray protein structures have been analyzed in respect of their structural features. The dihedral angles and hydrogen bonds of the helical sections that span the hydrophobic interior of the lipid bilayer have been investigated. The Ramachandran plot of protein channels and solute transporters exhibit a significant shift Δ (φ‐ and ψ‐angles) of Δ mean (+4.5° and −5.4°), compared to a reference group of 151 α‐helices of the same average length derived from water‐soluble globular proteins. At the C‐termini of transmembrane helices structural motifs equivalent to the Gly‐caps of helices in globular proteins have been found, with two third of the transmembrane Gly‐caps taking up a primary structure that is typically not found at helix termini exposed to a polar solvent. The structural particularities reported here are relevant for the three‐dimensional modelling of membrane protein structures.
Colonization and risk factors for Brachyspira aalborgi and Brachyspira pilosicoli in humans and dogs on tea estates in Assam, India
Authors: MUNSHI M. A. , TRAUB R. J. , ROBERTSON I. D. , MIKOSZA A. S. J. , HAMPSON D. J.
Published: January 2004

The prevalence of colonization with the anaerobic intestinal spirochaetes Brachyspira aalborgi and Brachyspira pilosicoli was investigated in humans (n=316) and dogs (n=101) living on three tea estates in Assam, India. Colonization was detected using PCR on DNA from faeces. Nineteen (6%) human faecal samples contained B. aalborgi DNA, 80 (25·3%) contained B. pilosicoli DNA, and 10 (3·2%) contained DNA from both species. One canine sample contained DNA from B. pilosicoli. Significant factors for B. aalborgi colonization in logistic regression were: infection of family members with B. aalborgi (P<0·001), being a resident of Balipara (P=0·03), and use of water treatment (P=0·03). For B. pilosicoli, significant factors were: other family members being positive for B. pilosicoli (P<0·001), water obtained from a well (P=0·006), water treatment (P=0·03), and not having visited a doctor in the previous 12 months (P=0·03).
Relations between the consumption of antimicrobial growth promoters and the occurrence of resistance among Enterococcus faecium isolated from broilers
Authors: EMBORG H.-D. , ANDERSEN J. S. , SEYFARTH A. M. , WEGENER H. C.
Published: January 2004

The present study investigates, at farm level, the effect of the time-span between sampling and the last time a particular antimicrobial growth promoter (AGP) was included in the feed on the probability of selecting an AGP-resistant Enterococcus faecium isolate from a broiler flock. The probability that a randomly selected E. faecium isolate was resistant to avilamycin, erythromycin or virginiamycin was 0·91, 0·92 and 0·84, respectively if the isolate originated from a broiler flock fed either avilamycin- or virginiamycin-supplemented feed. As the time-span between sampling and the last AGP consumption increased, the probability of isolating an E. faecium isolate resistant to a particular AGP decreased (probability <0·2 within 3–5 years after last exposure to AGPs). The decrease in probability over time showed little farm-to-farm variation. The number of times a particular AGP was given to previous flocks reared in the same house had no effect on the probability of isolating a resistant isolate.
Transmission of Salmonella between broiler chickens fed with fermented liquid feed
Authors: HERES L. , URLINGS H. A. P. , WAGENAAR J. A. , de JONG M. C. M.
Published: January 2004

In the light of food safety and the control of Salmonella at chicken farms, fermented liquid feed (FLF) was studied. This moistened feed reduced the susceptibility of chickens for Salmonella. To assess the effect of the fermented feed on the transmission of Salmonella between chickens, a transmission experiment was performed. Salmonella shedding was followed within groups of two susceptible chickens together with two previously inoculated chickens. The between-chicken transmission was quantified by calculating a reproduction ratio (R0) and a transmission rate parameter (β). R0 and β in the FLF-treated groups were reduced, but a typical infectious chicken fed with FLF, could on average still infect more than one new infectious case. FLF can therefore reduce the transmission of Salmonella in chicken flocks, but it will not prevent the occurrence of major outbreaks.
Estimation of the Salmonella enterica prevalence in finishing swine
Authors: HURD H. S. , McKEAN J. D. , GRIFFITH R. D. , ROSTAGNO M. H.
Published: January 2004

The study objective was to evaluate three methods of Salmonella enterica prevalence estimation in swine herds (faecal culture, culture of abattoir-collected samples, and serum ELISA). From each of six swine herds, we necropsied approximately 100 finishing pigs (>70 kg); one-half on farm and the other half at the abattoir, after transport and approximately 2·5 h holding. We collected the same samples for S. enterica culture at both locations (1 g faecal, 10 g caecal contents, ileocaecal lymph nodes, superficial inguinal lymph nodes, 25 g of gluteal muscle for serum ELISA). On farm, the 1 g faecal sample only detected 13·3% (2/15) of all positive pigs necropsied on farm. However, with abattoir and on-farm results combined, the faecal sample detected 57·4% (74/129) of positive pigs. Abattoir-collected samples provided prevalence estimates much higher than on-farm collected samples (39·9 vs. 5·3%; P<0·001). This study shows that faecal samples have a low sensitivity for detecting infected pigs and that abattoir-collected samples overestimate the on-farm S. enterica prevalence. For most herds, serology overestimated the on-farm culture prevalence.
Surveillance of severe invasive group-G streptococcal infections and molecular typing of the isolates in Japan
Authors: IKEBE T. , MURAYAMA S. , SAITOH K. , YAMAI S. , SUZUKI R. , ISOBE J. , TANAKA D. , KATSUKAWA C. , TAMARU A. , KATAYAMA A. , FUJINAGA Y. , HOASHI K. , WATANABE H.
Published: January 2004

The number of patients with severe invasive group-G streptococcal (Streptococcus dysgalactiae subsp. equisimilis) infections has been increasing in Japan. The emm genotypes and SmaI-digested pulsed-field gel electrophoresis DNA profiles were variable among the strains isolated, suggesting there has not been clonal expansion of a specific subpopulation of strains. However, all strains carried scpA, ska, slo and sag genes, some of which may be involved in the pathogenesis of the disease.
Faecal shedding and intestinal colonization of Salmonella enterica in in-bred chickens: the effect of host-genetic background
Authors: BARROW P. A. , BUMSTEAD N. , MARSTON K. , LOVELL M. A. , WIGLEY P.
Published: January 2004

Considerable and reproducible differences were observed in the amount and duration of faecal excretion when in-bred lines of chickens were infected orally with S. enterica serovar Typhimurium at 6 weeks of age after being given a gut flora preparation when newly hatched. Similar but less pronounced results were observed with S. Enteritidis or S. Infantis. Differences in the viable numbers of the inoculated bacteria in caecal contents were detectable within 24 h of inoculation. No major differences were seen in Salmonella-specific serum IgA or IgG titres. Small differences were seen in the numbers of circulating heterophilic cells. Caecal contents taken from the more resistant lines immediately prior to challenge appeared to be no more inhibitory for Salmonella in vivo than contents taken from susceptible lines. The more resistant lines showed a slightly higher rate of intestinal flow, as indicated by the rate of production of faecal droppings, although there was no difference in the rate of emptying of the caeca. In an F1 generation resistance was dominant and not sex-linked. There was no MHC linkage or any association with SAL1, the gene implicated in resistance to systemic salmonellosis in chickens, or NRAMP1.
A combined AFLP–multiplex PCR assay for molecular typing of Escherichia coli strains using variable bacterial interspersed mosaic elements
Authors: HORVÁTH R. , DENDIS M. , SCHLEGELOVÁ J. , RŮŽIČKA F. , BENEDÍK J.
Published: January 2004

The original method for molecular typing of E. coli strains was developed using the polymorphism in chromosomal sequences of bacterial interspersed mosaic elements (BIMEs) detected by multiplex PCR and analysed by AFLP assay. The applicability of the method in the epidemiology of E. coli was tested on a group of 524 strains of human and veterinary origin. In the studied group 18 different genotypes were detected. Significant differences were found in the frequencies of the genotypes among various groups of strains, suggesting the method could be a promising tool in the epidemiology of E. coli.
Present characteristics of symptomatic Entamoeba histolytica infection in the big cities of Japan
Authors: OHNISHI K. , KATO Y. , IMAMURA A. , FUKAYAMA M. , TSUNODA T. , SAKAUE Y. , SAKAMOTO M. , SAGARA H.
Published: January 2004

Medical records, for 2000 and 2001, of symptomatic amoebic patients who were treated at our hospitals in Tokyo, Yokohama and Osaka were studied retrospectively for the purpose of gathering epidemiological data on symptomatic Entamoeba histolytica infection. A total of 58 patients were treated. Fifty-five of them were male, and 96% of the male patients were Japanese. The mean age of patients was 44·9 years old, and 91% of patients contracted the disease in Japan. Fifty-six per cent of the male patients indicated that they were practising homosexuals, and 44% of the male patients denied these practices or left the question unanswered. The serum Treponema pallidum haemagglutination test was positive in 45% of the patients, and antibody to human immunodeficiency virus (HIV) was positive in 45%. Our study revealed that recent symptomatic E. histolytica infection almost exclusively afflicted middle-aged males in the big cities of Japan, that a majority of the patients were probably exposed to the causative organism during homosexual activity, and that an increasing number of patients will be co-infected with HIV.
Modelling responses to a smallpox epidemic taking into account uncertainty
Authors: LEGRAND J. , VIBOUD C. , BOELLE P. Y. , VALLERON A. J. , FLAHAULT A.
Published: January 2004

Epidemiology and modelling are currently under pressure to build consistent scenarios of control in case of deliberate release of biological weapons. In order to assess the key parameters for the control of a smallpox outbreak in a large city (2 million inhabitants), we built a stochastic model to simulate the course of an epidemic controlled by ring vaccination and case isolation. Assuming a reference scenario with 100 index cases and implementation of intervention 25 days after the attack, the model forecasts an epidemic of 730 cases with an epidemic duration of 240 days. Setting intervention 20 days later would result in an almost fourfold increase in the epidemic size. A multivariate sensitivity analysis has selected three key parameters: the basic reproduction number (i.e. the number of secondary cases infected by one case in an entirely susceptible population, equal to 3 in the reference scenario), time to intervention, and proportion of traced and vaccinated contacts.
Occupational exposure to hepatitis infection among Turkish nurses: frequency of needle exposure, sharps injuries and vaccination
Authors: KOSGEROGLU N. , AYRANCI U. , VARDARELI E. , DINCER S.
Published: January 2004

The aim of this study was to assess the demographic factors and pattern of injuries sustained by nurses, and to determine the occupational hazard of exposure to hepatitis B (HBV) and C (HCV) viruses among nurses. The study involved 906 hospital-based nurses working in three large hospitals. Between August 2002 and January 2003 a total of 595 practising nurses were accepted for inclusion. The results of questionnaires completed were collated and χ2 and ratios were used for analysis. Of the 595 nurses, 111 (18·7%) had evidence of previous or current HBV infection and 32 (5·4%) of HCV infection. We found that 11·2% of the nurses who had worked for a period of between 0 and 5 years and 37·1% of those who had worked for a period between 16 and 20 years had evidence of HBV or HCV infection. Of the nurses working in surgical clinics, 59·4% had evidence of previous HBV or HCV infection and those working in hospital clinics had an 18·2% infection rate. Of the nurses occupationally exposed to HBV and HCV infections, 22·4% had received sharps injuries from apparatus and 63·6% had suffered needlestick exposure. Findings also showed 2·7% HBsAg positivity and 5·4% anti-HCV positivity. Of the 452 (76%) nurses who faced the occupational hazard of exposure to hepatitis infections, 27·7% (125/452) had not been vaccinated against HBV. Nurses working in our health-care sector are frequently exposed to occupational exposure for HBV and HCV infections. In order to prevent the infection of nurses with hepatitis, we advocate precautions and protection from sharps injuries. A programme of education, vaccination and post-exposure prophylaxis must be implemented.
In vitro studies on the colonization of bovine colonic mucosa by Shiga-toxigenic Escherichia coli (STEC)
Authors: COBBOLD R. N. , DESMARCHELIER P. M.
Published: January 2004

This study investigated host-related factors that influence intestinal colonization by Shiga-toxigenic E. coli (STEC). A quantitative colonization assay was developed to comparatively measure attachment of STEC to bovine colonic tissues maintained in vitro. No differences were determined in colonization susceptibility between tissues derived from weaning calves and adult cattle, or for tissues from cattle fed grain and forage-based rations. Substrate conditions designed to represent various intra-enteric environments were tested for their effect on STEC/mucosal interaction. Under conditions corresponding to a well-fed ruminant (high volatile fatty acid and lactate concentrations, low pH), significantly less STEC colonized the mucosal surface of colonic biopsies. These results may help explain why fasted, poorly or intermittently fed cattle and pre-ruminant calves excrete STEC to a greater degree. Studies on the ecology of STEC within the ruminant gut help identify mechanisms to reduce their threat to public health.
EHEC outbreak among staff at a children's hospital – use of PCR for verocytotoxin detection and PFGE for epidemiological investigation
Authors: WELINDER-OLSSON C. , STENQVIST K. , BADENFORS M. , BRANDBERG Å. , FLORÉN K. , HOLM M. , HOLMBERG L. , KJELLIN E. , MÅRILD S. , STUDAHL A. , KAIJSER B.
Published: January 2004

This is the first report of a major foodborne outbreak of enterohaemorrhagic Escherichia coli (EHEC) in Sweden. It occurred among the nursing staff at a children's hospital with approximately 1600 employees. Contaminated lettuce was the most likely source of infection. Nine persons were culture-positive for Escherichia coli (E. coli) O157 and verocytotoxin-positive by PCR and a further two were verocytotoxin-positive by PCR only. All 11 EHEC-positive individuals had attended a party for approximately 250 staff members, which was held at the hospital. In a questionnaire 37 persons stated that they had symptoms consistent with EHEC infection during the weeks after the party. There was no evidence of secondary transmission from staff to patients. The value of PCR as a sensitive and fast method for diagnosis is discussed in this paper. Pulsed-field gel electrophoresis (PFGE) was used to ascertain that staff members were infected by the same clone, and that two patients with E. coli O157 infection were not.
Variability of Shigella flexneri serotypes in Israel during a period of two years: 2000 and 2001
Authors: VASILEV V. , ANDORN N. , JAPHETH R. , AGMON V.
Published: January 2004

During a period of 2 years (2000 and 2001) 996 Shigella flexneri strains from sporadic cases in Israel were sent to the National Shigella Reference Centre (NSRC) by hospital and outpatient clinics. The most common serotypes were 2a, 6 and 1b, accounting for 88·4% of all isolates. They were investigated according to the monthly distribution of the strains, and the age and sex of the patients. The severity of the disease was assessed by a hospital/outpatient distribution (H/Od) of the isolates, based on the location of the sending laboratory. The most affected age groups were 0–11 months and 1–4 years, and the prevalent serotype was 2a, while serotype 6 was dominant in the 5–14 years age group. More cases were registered during the hot season, and there were some serotype-related variations. Overall, 62·1% of the samples were from male patients. Serotype 1b was dominant in the male/female ratio, although it was third in general prevalence. According to the H/Od serotype 2a was more common in hospitalized males and serotype 6 in outpatients, both male and female. These variations, as well as changes in serotype prevalence in the past, underscore the importance of serotype monitoring as part of the public health strategies for reducing the burden of Shigella flexneri infections.
A novel method of oral fluid collection to monitor immunity to common viral infections
Authors: MORRIS-CUNNINGTON M. C. , EDMUNDS W. J. , MILLER E. , BROWN D. W. G.
Published: January 2004

Serological surveys among representative population samples have proved rare given their reliance on invasive sample collection. We therefore completed the first population-based postal survey of immunity in England and Wales using new oral fluid technology. This paper examines the feasibility of this new methodological approach. Nearly 5500 oral fluid samples were collected, with individual demographic and social data via a questionnaire, from persons under 45 years of age recruited through general practices. Instructions were accurately followed with only 1% of samples returned without risk-factor data. The overall response rate was 40%. Response was independently associated with age, sex and location. Response was highest in children aged 5–14 years, adult females and in rural locations. This approach allowed the successful collection of comprehensive individual risk data, but response rates in adults must be improved if oral fluid surveys are to routinely complement serological surveillance.
Gender difference in the incidence of shingles
Authors: FLEMING D. M. , CROSS K. W. , COBB W. A. , CHAPMAN R. S.
Published: January 2004

We investigated age- and gender-specific incidence of shingles reported in a large sentinel practice network monitoring a defined population over the years 1994–2001. In total, 5915 male and 8617 female incident cases were studied. For each age group, we calculated the relative risk of females to males presenting with shingles. Incidence rates of chickenpox and herpes simplex were examined similarly. Shingles incidence was greater in females in each age group (except for 15–24 years). Relative risks (female to male) were greatest in age groups 45–64 years (1·48) and 0–14 years (1·43). There were no gender differences in the incidence of chickenpox except in the 15–24 years age group (female excess): for herpes simplex there were female excesses in all age groups. Gender-specific age-standardized incidence rates of shingles were calculated for each year and showed a consistent female excess in each of the 8 years (average annual excess 28%).
Mycobacteraemia among HIV-1-infected patients in São Paulo, Brazil: 1995 to 1998
Authors: HADAD D. J. , PALACI M. , PIGNATARI A. C. C. , LEWI D. S. , MACHADO M. A. S. , TELLES M. A. S. , MARTINS M. C. , UEKI S. Y. M. , VASCONCELOS G. M. , PALHARES M. C. A.
Published: January 2004

From July 1995 to August 1998, mycobacterial blood cultures were obtained from 1032 HIV-infected patients seen at the Centro de Referência e Treinamento de AIDS (CRTA), Hospital São Paulo (HSP), and Centro de Referência de AIDS de Santos (CRAS). Overall, 179 episodes of mycobacteraemia were detected: 111 (62·0%) at CRTA, 50 (27·9%) at HSP, and 18 (10·1%) at CRAS. The frequency of positive cultures declined sharply from 22·6% in 1995 to 6·9% in 1998, consistent with the decrease in opportunistic infections following the publicly funded distribution of highly active antiretroviral therapy. In 1995, mycobacteraemia was more frequently due to Mycobacterium avium complex (59·2%) than Mycobacterium tuberculosis (28·6%), whereas in 1998 the relative frequencies were reversed (28·6 vs. 64·3% respectively), probably justified by the increased virulence of M. tuberculosis and the greater risk of invasive infection in less-immunocompromised patients, including patients unaware they are infected with HIV.
Negative impact of clinical misdiagnosis of measles on health workers' confidence in measles vaccine
Authors: HELFAND R. F. , CHIBI T. , BIELLIK R. , SHEARLEY A. , BELLINI W. J.
Published: January 2004

We conducted a survey to determine the accuracy of the clinical diagnosis of measles in Zimbabwe. Between December 1996 and February 1997, we collected blood samples and clinical and demographic information from a sample of 105 children with a clinical diagnosis of measles. A clinical case of measles was defined as a person with a history of fever, rash for three or more days, and either cough, coryza, or conjunctivitis. A laboratory-confirmed case of measles or rubella had IgM antibodies against measles virus or rubella virus respectively. A total of 91% of children met the clinical case definition. Among those who met the clinical case definition for measles, 72% were IgM-positive for measles virus only, 23% were IgM-positive for rubella virus only, 3% were IgM-positive for both measles and rubella viruses, and 2% were IgM-negative for both viruses. This study demonstrates the importance of considering selective laboratory confirmation of measles in periods of high disease incidence when the effectiveness of the vaccine is questioned.
Seroprevalence of measles, mumps and rubella antibodies in Luxembourg: results from a national cross-sectional study
Authors: MOSSONG J. , PUTZ L. , SCHNEIDER F.
Published: January 2004

A serological prevalence survey was carried out in Luxembourg during 2000–2001 to determine the antibody status of the Luxembourg population against vaccine-preventable infections. Blood samples of children and adolescents were collected prospectively in randomly selected schools. Samples of adults were obtained through volunteer patients of the national health laboratory or of the mandatory pre-nuptial test. Measles, mumps and rubella (MMR) virus antibody concentrations were measured using commercial ELISA tests. Age-standardized prevalence of measles, mumps and rubella virus antibodies was found to be 96·58, 75·40 and 95·69% respectively. Significant age-dependence of serology was observed for all three infections, with study participants born after the introduction of the MMR vaccine experiencing a gradual decline of antibodies following vaccination in childhood. Older study participants who were more likely to have antibodies from natural infection had consistently higher titres than younger individuals. Present vaccination coverage with MMR appears to be sufficient to prevent large local outbreaks of measles and rubella, but probably not mumps.
Attitudes of Potential Providers Towards Preconceptional Cystic Fibrosis Carrier Screening
Authors: Poppelaars Francis A. M. , Adèr Herman J. , Cornel Martina C. , Henneman Lidewij , Hermens Rosella P. M. G. , van der Wal Gerrit , Kate Leo P. ten
Published: January 2004

To determine the attitudes of potential providers (general practitioners and Community Health Service workers) towards preconceptional cystic fibrosis (CF) carrier screening and to determine which factors are associated with a positive attitude. A survey was conducted among 200 general practitioners (GPs) and 134 Community Health Service (CHS) workers. Fifty‐two percent of the eligible GPs participated and 84% of the CHS workers. Fifty‐five percent of the GPs and 73% of the CHS workers had a positive attitude towards routinely offering CF carrier screening, and more than 80% were in favor of informing the target population about the possibility of having a CF carrier test. A positive attitude was associated with (a) high perceived severity of CF, (b) religion (nonreligious compared to Reformed), (c) low perceived barriers, and (d) high perceived test reliability. The care providers who are most likely to be involved in a preconceptional CF carrier screening program, i.e. GPs and CHS workers, generally have a positive attitude towards the implementation of such a program.
Adjunct Prenatal Testing: Patient Decisions Regarding Ethnic Carrier Screening and Fluorescence In Situ Hybridization
Authors: Sturm Erica L. , Ormond Kelly E.
Published: January 2004

Little has been reported regarding how women make decisions about genetic carrier screening for Ashkenazi Jewish genetic disease and cystic fibrosis (CF), and for fluorescent in situ hybridization (FISH) during pregnancy. Thirty‐seven women who underwent genetic counseling and prenatal diagnosis were interviewed about their prenatal decision making. Respondents were largely Caucasian (95%), and undergoing prenatal diagnosis because of maternal age (78%). Sixty‐three percent of those who reported having genetic carrier screening correctly defined it; 83% felt positively about it. Primary reasons reported for electing screening were: to get information, to be prepared, perception of risk, wanting peace of mind and percieved inability to care for an affected child. Women who declined screening felt they had very little or no risk, and some were deterred by cost. Ninety‐five percent of respondents elected to have FISH; most were motivated by its speed in providing information and peace of mind or by timing of when the procedure was performed. Those who declined FISH reported being less concerned about having an affected child, receiving bad news, or waiting 2 weeks for results and slightly less affected by their “feelings toward medical testing” or physician's suggestion. These findings suggest decision‐making factors differ between those electing and declining adjunct prenatal testing and increased knowledge about these factors may impact the way in which these services are offered by health care professionals. Prospective research with a larger population will be useful in further delineating the factors that influence prenatal decisions about adjunct testing measures.
“Family Matters”: A Conceptual Framework for Genetic Testing in Children
Authors: McConkie‐Rosell Allyn , Spiridigliozzi Gail A.
Published: January 2004

Genetic testing in minor children presents a complex ethical and social problem. Current guidelines state that genetic testing of children is recommended only under circumstances where a clear medical or psychosocial benefit to the child can be demonstrated. Because of the difficulty in determining a psychosocial benefit, the discussion about genetic testing of minors ultimately tends to focus on who has the right to make the decision and whose right to autonomy is jeopardized, the parent's or the child's, when there is no identified medical benefit. Historically, a western bioethics paradigm, Principlism, has been used to guide genetic counseling sessions and genetic‐testing guidelines for minors. This bioethics paradigm is guided by the principles: respect for autonomy, beneficence, nonmaleficence, and justice. Genetic testing in children, when viewed through a traditional bioethics filter is limited by its focus on the individual because children are not only individuals, they are also integral parts of a larger social context, that of their family. Because this bioethics paradigm places a strong emphasis on individual autonomy, the family's beliefs and values and the parents' concern for their children may be overshadowed by the medical community's attempt to preserve the child's “right” to an autonomous decision about genetic testing. The purpose of this paper is to first discuss the circumstances in which genetic testing of minors occurs and then present a theoretical and ethics‐based conceptual framework that may be useful in the development of genetic counseling interventions.
Temporal changes in Nd isotopic composition of Piton de la Fournaise magmatism (Réunion Island, Indian Ocean)
Authors: Luais Béatrice
Published: January 2004

A Nd isotopic study of twelve historical samples and fifty‐seven core samples covering the last 530 ka of volcanic activity of the Piton de la Fournaise volcano of Réunion Island was undertaken, with additional new Sr isotopic analyses of historical samples. The core samples were obtained from the cliffs of the deep (ca.1000 m) canyons of the Remparts and Langevin Rivers. Four types of rocks, namely basalts (MgO = 5–9 wt.%), high‐Mg basalts (MgO = 10–20 wt.%), plagioclase‐rich basalts, and differentiated samples (SiO2 = 48–53 wt.%) occur randomly throughout the lava sections. The overall variations in Nd isotopic ratios (0.512751 to 0.512902) are small, but significant. The range of Nd isotopic variations is larger than previously described in the literature, and extends toward lower values. Nd isotopic ratios increase through time and are broadly negatively correlated with the alkalinity index. The older alkaline Remparts samples (527–290 ka) (average εNd = +3.26) exhibit lower 143Nd/144Nd ratios than the younger tholeiitic Langevin samples (70–40 ka) (average εNd = +4.17) and the historical lavas (1901–1956) (average εNd = +4.74). Comparison of 143Nd/144Nd ratios with available 87Sr/86Sr ratios on the same set of samples (Remparts and Langevin series [Albarède et al., 1997]; historical series, this study) shows no correlation between Sr and Nd isotopes. It is suggested that the high Nd isotopic ratios of historical tholeiitic samples would be representative of the isotopic composition of the Réunion plume. The increase in Nd isotopic ratios over 530 ka reflects the effect of decreasing contribution of an enriched component to the Réunion plume through time. This enriched component would occur as isolated blobs in the mantle source.
Combined effects of tectonics and glacial isostatic adjustment on intraplate deformation in central and northern Europe: Applications to geodetic baseline analyses
Authors: Marotta A. M. , Mitrovica J. X. , Sabadini R. , Milne G.
Published: January 2004

We use a suite of spherical, thin sheet, finite element model calculations to investigate the pattern of horizontal tectonic deformation within Europe. The calculations incorporate the effects of Africa‐Eurasia convergence, Atlantic Ridge push forces, and changes in the lithospheric strength of the East European and Mediterranean subdomains. These predictions are compared to the deformation computed for the same region using a spherically symmetric, self‐gravitating, viscoelastic Earth model of glacial isostatic adjustment. The radial viscosity profile and ice history input into the GIA model are taken from a model that “best fits” three‐dimensional crustal velocities estimated from the BIFROST Fennoscandian GPS network. The comparison of the tectonic and GIA signals includes predictions of both crustal velocity maps and baseline length changes associated with sites within the permanent ITRF2000 and BIFROST GPS networks. Our baseline analysis includes reference sites in northern and central Europe that are representative of sites at the center, edge, and periphery of the GIA‐induced deformation. Baseline length change predictions associated with all three reference sites are significantly impacted by both tectonic and GIA effects, albeit with distinct geometric sensitivities. In this regard, several of our tectonic models yield baseline rates from Vaas, Onsala, and Potsdam to sites below 55°N which are consistent with observed trends. We find that a best fit to the ITRF2000 data set is obtained by simultaneously considering the effects of GIA plus tectonics, where the latter is modeled with a relatively weak Mediterranean subdomain. In this case, the tectonic model contributes to the observed shortening between Onsala/Potsdam and sites to the south, without corrupting the extension observed for baselines extending from these reference sites and sites to the north; this extension is well reconciled by the GIA process alone.
The source of the high heat and freshwater content of the upper ocean at the SHEBA site in the Beaufort Sea in 1997
Authors: Kadko David , Swart Peter
Published: January 2004

Measurements of 7Be and oxygen isotope (18O/16O) ratios from the 1997–1998 SHEBA experiment were used to trace the source of the high heat and freshwater content of the upper ocean observed during the initial occupation of the SHEBA site in October 1997. The evidence suggests that the heating resulted from local input primarily through extended lead coverage in the late spring and summer of 1997 with no requirement of advective input. The freshening was derived from a large ice melt (1.2 m) that was consistent with the thin ice and extensive melt pond coverage (by then frozen) observed at the site. However, a significant contribution to the freshwater budget (0.8 m) included enhanced input from river runoff during the melt season. This obviates the requirement for an unrealistically large ice melt (∼2 m) to account for the freshwater content of the mixed layer, and would have increased the stratification stability of the upper ocean that in turn would have promoted local heating. The question then arises, however, as to the fate of the significant upper ocean heat at SHEBA in the fall 1997 which resulted from an active heating season. Similar evaluation of the fall 1998 SHEBA site indicate that the ice melt was comparable to that of 1997, but the riverine input and stored water column heat were less than in the previous year.
SIFTER: Signal inversion for target extraction and registration
Authors: Fridman Sergey V. , Nickisch L. J.
Published: January 2004

Signal inversion for target extraction and registration (SIFTER) is a technique for enhanced radar target detection and coordinate registration (CR). The technique is currently being developed for over‐the‐horizon radar (OTHR). The power received by a radar as a function of radar coordinates and Doppler shift may be expressed as an integral operator applied to the field of backscatter cross section (FBC) per unit area of the illuminated region. The FBC is a function of the geographic position and the velocity vector of the scattering point. The kernel of the integral operator is treated as a known function that is determined by the model of the propagation channel, antenna patterns, and the radar signal processing parameters. The relationship between the FBC and the received power is treated as an integral equation to be resolved with respect to the FBC. This inversion is accomplished using techniques for ill‐posed problems. The obtained FBC is subsequently analyzed for peaks. The location of a peak provides an estimate for actual ground coordinates and velocity vector of the target. Gain in sensitivity and CR is achieved by introducing a continuity equation, which evolves the FBC between radar revisit cycles. The evolved FBC is corrected using data from each subsequent revisit. Two versions of the SIFTER algorithm are presented. One is based on Tikhonov’s method, and the other is based on the Kalman filter method. SIFTER concepts and performance are demonstrated using modeled data.
Annual carbon dioxide drawdown and the Northern Annular Mode
Authors: Russell Joellen L. , Wallace John M.
Published: January 2004

Year‐to‐year variations in summer drawdown of Northern Hemisphere atmospheric carbon dioxide (CO2) are compared with corresponding year‐to‐year variations in sea‐level pressure (SLP), surface air temperature, and the productivity of land vegetation as inferred from the satellite‐derived normalized difference vegetation index (NDVI). Annual values of CO2 drawdown for the years 1980–2000 are estimated from smoothed time series derived directly from individual flask samples at the nine Northern Hemisphere monitoring stations with the most continuous records. The leading principal component of the nine standardized drawdown time series, in which all stations exhibit positive loadings, is used to represent the hemispheric signal in the CO2 drawdown. Linear regression analysis is used to infer the spatial patterns of anomalies in sea‐level pressure, surface air temperature, and the NDVI observed during various seasons of years in which the drawdown is anomalously strong. Winters preceding anomalously high drawdown seasons exhibit patterns characteristic of the high index of the Northern Annular Mode (NAM). SLP tends to be anomalously low over the Arctic and high over midlatitudes, and Eurasia tends to be anomalously warm. The pattern of the NDVI observed during the early months of the growing season in years with anomalously high drawdown is indicative of high productivity over Eurasia. These results support the notion that the wintertime NAM influences the annual drawdown of CO2 by modulating winter temperatures that, in turn, affect the productivity of the terrestrial biosphere during the subsequent growing season.
Geochemical indices allow estimation of heavy metal background concentrations in soils
Authors: Hamon R. E. , McLaughlin M. J. , Gilkes R. J. , Rate A. W. , Zarcinas B. , Robertson A. , Cozens G. , Radford N. , Bettenay L.
Published: January 2004

Defining background concentrations for heavy metals in soils is essential for recognizing and managing soil pollution. However, background concentrations of metals in soils can vary naturally by several orders of magnitude. Moreover, many soils have also been subject to unquantifiable anthropogenic inputs of metals, in some cases, for centuries. Hence determination of heavy metal background concentrations in soils has to date been fraught with difficulty. Here we demonstrate that there are associations between the background heavy metal and Fe or Mn contents in soils which appear to be consistent for seven important heavy metals of environmental concern. The relationships are remarkably independent of both soil type and climatic setting. These observations provide the basis for a series of general equations from which it is proposed Southeast Asian including Australian, and possibly worldwide background concentrations for As, Cr, Co, Cu, Ni, Pb, and Zn in soils can be derived.
Biotic contribution to air‐sea fluxes of CO2 and O2 and its relation to new production, export production, and net community production
Authors: Oschlies Andreas , Kähler Paul
Published: January 2004

The contribution of the marine biota to air‐sea fluxes of CO2 and O2 is often described in terms of biological production concepts, such as new production, export production, and net community production. We evaluate these three quantities using a basin‐scale ecosystem‐circulation model of the North Atlantic Ocean based on Redfield stoichiometry into which we introduce an artificial tracer which records the biotic contribution to air‐sea exchange of gases like O2 and CO2. It is found that on average the biological production rates overestimate the biotically effected air‐sea flux by some 20% and, in some regions, even predict the wrong direction. With primary production restricted to the euphotic zone, but respiration extending to farther below, the discrepancy can largely be attributed to the different integration depths used in the different concepts (euphotic zone, surface mixed layer), and on annual and longer timescales, all rates converge when using the base of the winter mixed layer rather than that of the euphotic zone as the reference depth. For the surface carbon budget, which ultimately controls air‐sea exchange of CO2, it is irrelevant whether carbon atoms cross this boundary in organic or inorganic speciation. Hence the transports of biotically generated surpluses or deficits of dissolved inorganic matter must also be accounted for. While their contribution amounts to only a few percent on the basin scale, the subduction of newly remineralized inorganic matter can locally account for about half of the biotically effected air‐sea flux, for example, in regions of mode‐water formation.
Antimony in recent, ombrotrophic peat from Switzerland and Scotland: Comparison with natural background values (5,320 to 8,020 14C yr BP) and implications for the global atmospheric Sb cycle
Authors: Shotyk William , Krachler Michael , Chen Bin
Published: January 2004

The lowest concentrations, atmospheric fluxes, and enrichments of Sb in a Swiss bog were found in peat samples dating from 8,020 to 5,320 14C yr BP when Sb inputs were proportional to those of Sc and effectively controlled by deposition of soil dust. For comparison with these ancient samples, modern peat samples from five rural areas of Switzerland and two remote areas of Scotland and Shetland are highly contaminated with Sb, with enrichments of the order of 30 to 80 times. “Lithogenic” Sb concentrations calculated using the Sc concentrations and background Sb/Sc ratio are dwarfed at all sites by “anthropogenic” Sb. The chronology and intensity of the Sb enrichments are in many ways similar to those of Pb which indicates that (1) Sb, like Pb, is well preserved in ombrotrophic peat and (2) the extent of human impacts on the geochemical cycle of Sb is comparable to that of Pb. The similar distribution of Sb and Pb can be explained in terms of their chemical and mineralogical associations, with most lead minerals being rich in Sb. Assuming that the “background” Sb flux (0.35 μg/m2/yr) from the Swiss bog is representative of preanthropogenic deposition rates worldwide, the global flux of natural Sb is estimated at 154 T/a. Using the natural Pb flux published by Patterson and Settle [1987] of 2600 T/a and the “background” Pb/Sb ratio (29) of the preanthropogenic peat samples, the global flux of natural Sb is estimated at 90 T/a. Either way, these values (90 to 154 T/a) are considerably lower than the current estimate of natural Sb to the global atmosphere (2400 T/a) published by Pacyna and Pacyna [2001]. Assuming that the current estimate of anthropogenic Sb to the global atmosphere (1600 T/a) is correct [Pacyna and Pacyna, 2001], the ratio of anthropogenic to natural Sb emissions is on the order of 10 to 18. Taken together, the data from modern and ancient peat samples suggests that the impact of human activities on the global geochemical cycle of Sb may have been underestimated by an order of magnitude. Like Pb, Sb has no known biological function, has a similar toxicity, and is a cumulative poison. The environmental geochemistry of Sb therefore may have a relevance to human and environmental health comparable to that of Pb.
Drifting airglow patches in relation to tail reconnection
Authors: Lorentzen D. A. , Shumilov N. , Moen J.
Published: January 2004

In this study we present optical ground‐based signatures of drifting airglow patches in the polar ionospheric F‐layer, in the evening/nighttime MLT sector. The patches were observed under predominately IMF BZ < 0, IMF BY > 0 conditions, which are favorable for high‐density sunlit plasma to be entrained into the polar cap with the large afternoon cell in the northern hemisphere. The patch morphology, such as altitude, meridional convection speed, and repetition rate was investigated using a meridian scanning photometer, and put into the context of activity changes in the auroral substorm. It was found that the meridional patch speed was modulated by the ongoing substorms, and that the patches crossed the open/closed field line boundary (OCB), even during late recovery, and subsequent growth phase. We take this as an indication of ongoing tail reconnection, and we therefore propose that the patches can be used as a tracer for tail reconnection when they cross the OCB and enter the nighttime auroral oval.
Support Vector Machine (SVM) pattern recognition to AVO classification
Authors: Li Jiakang , Castagna John
Published: January 2004

The purpose of this paper is to present a learning algorithm to classify data with nonlinear characteristics. The Support Vector Machine (SVM) is a novel type of learning machine based on statistical learning theory [Vapnik, 1998]. The support vector machine (SVM) implements the following idea: It maps the input vector X into a high‐dimensional feature space Z through some nonlinear mapping, chosen a priori. In this space, an optimal separating hyperplane is constructed to separate data groupings. The support vector machine (SVM) learning method can be used to classify seismic data patterns for exploration and reservoir characterization applications. The SVM is particularly good at classifying data with nonlinear characteristics. As an example the SVM method is applied to AVO classification of gas sand and wet sand.
Correction of TOPEX/POSEIDON altimeter data for nonisostatic sea level response to atmospheric pressure in the Japan/East Sea
Authors: Nam Sung Hyun , Lyu Sang Jin , Kim Young Ho , Kim Kuh , Park Jae‐Hun , Watts D. Randolph
Published: January 2004

High frequency (2–20 days) sea level fluctuations, driven by atmospheric pressure changes, must be eliminated from TOPEX/POSEIDON altimeter data, else these data sampled at 10‐day interval will suffer aliasing when interpreted as lower frequency variability of the subsurface pressure and circulation. A simple analytic Helmholtz‐like model [Lyu et al., 2002], which explains successfully the nonisostatic sea level response in the Japan/East Sea (JES), is applied to correct the high‐frequency sea level fluctuation effects on the T/P data. The model removes these pressure‐driven fluctuations better than the standard inverse barometer (IB) method, leaving residuals smaller by about 10% in the corrected mean sea level (MSL) data used in this study. Because the maximum difference between the model correction and the IB correction can reach 10 cm, the impact of the correction choice is substantial. Moreover, uncorrected or IB corrected T/P along‐track data contain substantial high frequency variability which can lead to ‘trackiness’ errors between crossing and neighboring tracks, contaminating their use for synoptic mapping. The model correction reduced the trackiness significantly better than the usual IB correction.