bluuebunny/crossref_metadata_2025_split huggingface dataset:
Response of secondary Production and its components to multiple stressors in nematode field populations
Authors: DOROSZUK AGNIESZKA , TE BRAKE ELSKE , CRESPO‐GONZALEZ DAVID , KAMMENGA JAN E. 
Published: February 2007

Summary

Realistic measures of the impact of individual or multiple stressors are important for ecological risk assessment. Although multiple anthropogenic stressors are common in human‐dominated environments, knowledge of their influence on functional population parameters such as secondary production (P) and biomass turnover (P/B) is very limited. Secondary production integrates population characteristics such as biomass, size–frequency distribution and body growth rate, and provides a link between population and system ecologies.
The influence of copper and pH stress on yearly secondary production and biomass turnover of field populations of the nematode Acrobeloides nanus was investigated by using a randomized factorial block design. The responses of the components of secondary production were also analysed in order to elucidate the mechanisms underlying the change in secondary production.
Secondary production and biomass turnover showed reduced values in soil of low pH. A negative effect of copper on both parameters was observed only when the copper load was combined with low pH, otherwise higher copper concentrations resulted in higher secondary production and biomass turnover.
The observed response of production and biomass turnover was mainly driven by changes in mean relative growth rate (MRGR), a measure of body growth rate estimated in a laboratory soil experiment. The biomass was higher on average in the plots with high copper load, while no significant response to pH was found.
Synthesis and applications. Our results demonstrate that populations of soil organisms may experience strong synergistic effects of combined stressors (acidification and copper stress) on functional population parameters while showing no detrimental effects on biomass. Moreover, the effects on secondary production and biomass turnover rate are predominantly driven by effects on body growth rate. We recommend that ecological risk assessment methodologies should include consideration of soil contamination on the basis of conservation of functional properties of ecosystems and their key components.
Competitive dynamics in two‐ and three‐component intercrops
Authors: ANDERSEN METTE KLINDT , HAUGGAARD‐NIELSEN HENRIK , WEINER JACOB , JENSEN ERIK STEEN 
Published: February 2007

SummaryIntercropping is receiving increasing attention because it offers potential advantages for resource utilization, decreased inputs and increased sustainability in crop production, but our understanding of the interactions among intercropped species is still very limited.We grew peaPisum sativum, barleyHordeum vulgareand rapeBrassica napusas sole crops and intercrops under field conditions using a replacement design. We collected total dry matter data from sequential harvests and fitted the data to a logistic growth model. At each harvest we estimated the relative Competitive Strength (CS) of the three crops by fitting the data to a simple interspecific competition model.The pea monocrop produced the largest amount of biomass from the middle to the end of the growth period, but pea was not dominant in intercrops.Fitting data to a logistic growth model emphasizes the importance of initial size differences for interactions among intercrops. Barley was the dominant component of the intercrops largely because of its initial size advantage. The competitive effect of barley on its companion crops, measured as CS, increased throughout most of the growing season.The performance of each crop species was very different when it grew with a second species rather than in monoculture, but addition of a third crop species had only minor effects on behaviour of the individual crops.Synthesis and applications.Including sequential harvests in experiments on intercropping can provide important information about how competitive hierarchies are established and change over time. Our results suggest that increased understanding of the role of asymmetric competition among species and the resulting advantages of early germination and seedling emergence would be valuable in designing intercrops. More focus on understanding the mechanisms that govern interactions between intercropped species is needed for designing optimized intercropping systems.
Operationalizing quality of life for people with profound multiple disabilities: a Delphi study
Authors: Petry K. , Maes B. , Vlaskamp C. 
Published: February 2007

AbstractBackground  In a recent study, we constructed an item pool that contains items on the quality of life (QOL) and related aspects of support of people with profound multiple disabilities (PMD). In the present study, a panel of experts assessed the content and the structure of this item pool in order to enhance its validity and usefulness.Method  A two‐round Delphi study was set up. The panel consisted of 45 experts, of whom 12 were theory‐experts, 12 practice‐experts and 12 experience‐experts from Belgium (n = 12), Germany (n = 12), the Netherlands (n = 11) and the UK/Ireland (n = 10). Both quantitative and qualitative methods of analysis were applied to the data.Results  The majority of the items were considered relevant for the QOL of people with PMD. In the first round, 91% of the items reached the 80% criterion of consensus. In the second round, 78.7% of the items reached the 85% criterion of consensus. There were no significant differences in opinion neither between types of experts nor between countries. Several items were reported as missing in the item pool and were added.Conclusions  The results provide some evidence that the item pool is a valid operationalization of QOL of people with PMD and can be used in an instrument to measure the QOL of this target group.
Elevated concentrations of asymmetric dimethylarginine are associated with deterioration of glucose tolerance in women with previous gestational diabetes mellitus
Authors: Mittermayer F. , Kautzky‐Willer A. , Winzer C. , Krzyzanowska K. , Prikoszovich T. , Demehri S. , Wagner O. , Wolzt M. 
Published: February 2007

Abstract.Objective.  Women with previous gestational diabetes mellitus (GDM) have a high risk for development of type 2 diabetes mellitus. The endogenous nitric oxide synthase inhibitor asymmetric dimethylarginine (ADMA) could be related to disorders of the glucose metabolism. To evaluate if ADMA predicts deterioration of glucose tolerance in women with previous GDM and to assess concentration changes we analysed ADMA in women with previous GDM after delivery and after a median follow‐up of 2.75 years (interquartile range: 1.47–4.60).Design.  Prospective cohort study.Subjects and methods.  ADMA, symmetric dimethylarginine (SDMA) and l‐arginine were determined in 77 women with previous GDM who underwent a 75‐g oral glucose tolerance test 4 months after delivery and at follow‐up.Results.  Deterioration in glucose tolerance was observed in 36% of the women with ADMA above and 11% of those with ADMA below the median (0.56 μmol L−1; P = 0.008, log‐rank test). ADMA correlated significantly with mean arterial blood pressure and nonsignificantly with body mass index (P = 0.050) but not with insulin resistance, fasting glucose, lipids or glomerular filtration rate. The fully adjusted hazard ratio for a decline of glucose tolerance during follow‐up was 3.94 (95% CI: 1.16–13.37; P = 0.028) for subjects with ADMA above the median. SDMA and l‐arginine were not associated with changes in the glucose tolerance status. ADMA and l‐arginine decreased significantly during follow‐up.Conclusions.  High serum ADMA after delivery is associated with deterioration in glucose tolerance in women with previous GDM and declines in the following years.
Metabolic syndrome, its preeminent clusters, incident coronary heart disease and all‐cause mortality – results of prospective analysis for the Atherosclerosis Risk in Communities study
Authors: Hong Y. , Jin X. , Mo J. , Lin H.‐M. , Duan Y. , Pu M. , Wolbrette D. L. , Liao D. 
Published: February 2007

Abstract.Objective.  To investigate the prospective association between Metabolic Syndrome (MetS) and coronary heart disease (CHD) and all‐cause mortality.Subjects and Design.  A bi‐racial cohort of 14 699 middle‐aged Americans from the Atherosclerosis Risk in Communities study were followed for the development of new CHD and death over a period of 9 years. MetS, using the original ATP‐III criteria, was defined as having at least three of the following components: elevated blood pressure (BP), elevated plasma glucose, elevated blood triglyceride (TG), increased waist circumference, and low HDL cholesterol (HDL‐c). Incident CHD cases included hospitalized myocardial infarction (MI), fatal CHD, revascularization procedures, and silent MI as detected by EKG.Results.  The prevalence of the MetS at baseline was 29%, 30%, 40% and 26% among CHD‐free white women, white men, black women, and black men, respectively. There were 1018 incident CHD cases and 1039 deaths. The relative risk (RR) and 95% confidence interval (CI) of incident CHD associated with MetS was 2.46 (1.99, 3.03) for women and 1.86 (1.59, 2.18) for men. Clear dose–response relationship between the number of MetS components and incidence of CHD was found (P for linear trend <0.001). The following three clusters of MetS components posed the highest risk for CHD: (i) the elevated BP and glucose and low HDL‐c group [RR = 5.68 (3.44, 9.37)]; (ii) the elevated BP and glucose and TG group [RR = 5.08 (2.96, 8.70)]; and (iii) the elevated BP and TG and low HDL‐c group [RR = 3.98 (2.75, 5.77)]. When all five components co‐existed, the risk was the highest [RR = 6.24 (4.65, 8.36)]. Similar results with attenuated RR were found for all‐cause mortality.Conclusions.  Individuals, especially women, with the MetS have significantly higher risk of developing CHD. The riskiest combination is high‐BP and glucose clustered with low HDL‐c or high TG. These data highlight the importance of targeting MetS in the prevention of CHD and premature death.
Unique patient with cerebrotendinous xanthomatosis. Evidence for presence of a defect in a gene that is not identical to sterol 27‐hydroxylase
Authors: Hansson M. , Olin M. , Floren C.‐H. , Von Bahr S. , Van't Hooft F. , Meaney S. , Eggertsen G. , Björkhem I. 
Published: February 2007

Abstract.Cerebrotendinous xanthomatosis (CTX) is a rare autosomal recessive disorder believed to be exclusively caused by mutations in the CYP27A1 gene coding for the enzyme sterol 27‐hydroxylase. Common findings in CTX are tendon xanthomas, cataracts and progressive neurological dysfunction. Here, we characterize an adult female patient with tendon xanthomas and classic biochemical findings of CTX (i.e. high levels of bile alcohols and cholestanol and extremely low levels of 27‐hydroxycholesterol in plasma). Additionally, sterol 27‐hydroxylase activity in cultured monocyte‐derived macrophages from this patient was <5% of normal. Sequencing the CYP27A1 gene uncovered that the patient is heterozygous for two previously undescribed base substitutions in exon 8, C478A and C479A, which are expected to affect the haeme‐binding domain of the enzyme. When expressed in HEK293 cells, the corresponding protein had only 8% of normal enzymatic activity. No other mutation was found in the open reading frame of the CYP27A1 gene, intron–exon boundaries or in the 5′‐untranslated region up to 5000 bp distal to the translational start site. Sequencing mRNA isolated from leucocytes from the patient revealed a 1 : 1 ratio of mutated and nonmutated species, with total mRNA levels that were not significantly different from the controls. It is concluded that the patient is heterozygous for two mutations affecting one allele of the CYP27A1 gene and with at least one additional yet undefined gene that is of critical importance for the activity of sterol 27‐hydroxylase.
Elemental distributions in femoral bone of rat under osteoporosis preventive treatments
Authors: YNSA M. D. , AGER F. J. , ALVES L. C. , ZUBELDIA M. A. , MILLÁN J. C. , PINHEIRO T. 
Published: February 2007

SummaryOne of the abnormalities of bone architecture is osteoporosis as occurring in post‐menopausal women. Especially long bones, such as femur, become more fragile and more prone to fracture. The efficiency of several osteoporosis preventative treatments based on oestrogen and progestin in bone structure and mineral recovery was studied using ovariectomized Wistar rats as an osteoporosis experimental model. Diagonal cross‐sections of the proximal epiphysis of femoral bones were analysed using nuclear microscopy techniques in order to map and determine the concentration profiles of P, Ca, S, Fe and Zn from the epiphysis to diaphysis and across the cortical and trabecular bone structures. In control animals (not ovariectomized), the S and Zn contents significantly characterized differences between cortical and trabecular bone structures, whereas P and Ca showed increased gradients from the epiphyseal region to the diaphysis. After ovariectomy the differences observed were differential according to the type of hormonal supplementation. A significant decrease in P and Ca contents and depletion of minor and trace minerals, such as S, Fe and Zn, were found for both cortical and trabecular bone structures after ovariectomy relative to controls. Bone mineral contents were reversed to control levels by synthetic oestrogen supplementation, and combined oestrogen and progesterone treatment. Recovery was more evident in the femoral epiphysis and neck than in the diaphysis. The use of oestrogen alone did not lead to bone recovery after ovariectomy. Alterations in bone mineral composition observed for animals receiving synthetic oestrogen and combined oestrogen and progesterone supplement might reflect beneficial structural changes in critical regions of long bones, mostly affected in post‐menopausal osteoporosis.
Sleep problems and daytime somnolence in a German population‐based sample of snoring school‐aged children
Authors: EITNER STEFFEN , URSCHITZ MICHAEL S. , GUENTHER ANKE , URSCHITZ‐DUPRAT PILAR M. , BOHNHORST BETTINA , SCHLAUD MARTIN , POETS CHRISTIAN F. 
Published: February 2007

SummaryHabitual snoring is associated with daytime symptoms like tiredness and behavioral problems. Its association with sleep problems is unclear. We aimed to assess associations between habitual snoring and sleep problems in primary school children. The design was a population‐based cross‐sectional study with a nested cohort study. The setting was twenty‐seven primary schools in the city of Hannover, Germany. Habitual snoring and sleep problems were assessed in primary school children using an extended version of Gozal's sleep‐disordered breathing questionnaire (n = 1144). Approximately 1 year later, parents of children reported to snore habitually (n = 114) and an equal number of children who snored never or occasionally were given the Sleep Disturbance Scale for Children, a validated questionnaire for the assessment of pediatric sleep problems. Snoring status was re‐assessed using the initial questionnaire and children were then classified as long‐term habitual snorers or ex‐habitual snorers. An increasing prevalence of sleep problems was found with increasing snoring frequency for sleep‐onset delay, night awakenings, and nightmares. Long‐term habitual snorers were at significantly increased risk for sleep–wake transition disorders (e.g. rhythmic movements, hypnic jerks, sleeptalking, bruxism; odds ratio, 95% confidence interval: 12.0, 3.8–37.3), sleep hyperhidrosis (3.6, 1.2–10.8), disorders of arousal/nightmares (e.g. sleepwalking, sleep terrors, nightmares; 4.6, 1.3–15.6), and excessive somnolence (i.e. difficulty waking up, morning tiredness, daytime somnolence; 6.3, 2.2–17.8). Ex‐habitual snorers were at increased risk for sleep–wake transition disorders (4.4, 1.4–14.2). Habitual snoring was associated with several sleep problems in our study. Long‐term habitual snorers were more likely to have sleep problems than children who had stopped snoring spontaneously.
Absorption, psychological boundaries and attitude towards dreams as correlates of dream recall: two decades of research seen through a meta‐analysis
Authors: BEAULIEU‐PRÉVOST DOMINIC , ZADRA ANTONIO 
Published: February 2007

SummaryMany studies have reported positive correlations between dream recall frequency (DRF) and measures of absorption, psychological boundaries and attitude towards dreams. A majority of these studies, however, have relied exclusively on retrospective measures of DRF even though daily dream logs are generally considered to be more direct and valid measures of DRF. The first goal of the present meta‐analysis was to evaluate the effect sizes of three variables (absorption, psychological boundaries and attitude towards dreams) as correlates of DRF. The second goal was to evaluate if these effect sizes varied as a function of how DRF was operationalized (i.e. retrospective measure versus dream log). Data from 24 studies were included in the analyses. For each of the three variables investigated, correlations with retrospective measures of DRF were of greater magnitude than those obtained with daily logs. These results indicate that scores on measures of absorption and psychological boundaries are not related to DRF per se, but rather to people's tendency to retrospectively underestimate or overestimate their DRF, while attitude towards dreams is related both to DRF per se and to people's retrospective estimation bias. Implications of these findings for dream research are discussed.
Mortality risk factors in sleep apnoea: a matched case–control study
Authors: LAVIE PERETZ , HERER PAULA , LAVIE LENA 
Published: February 2007

SummarySleep apnoea syndrome was reported to be associated with increased mortality but it is not known if this association is independent of obesity and co‐morbidities. The present study investigated predictors of mortality in a large cohort of men with sleep apnoea using a case–control design. The study population consisted of 10 981 men diagnosed during 1991–2000 by whole‐night polysomnography with sleep apnoea; 331 men died prior to 1 September 2001, of whom 277 were matched by age, gender, site and time of study to patients who were alive in September 2001. Multivariate analysis revealed that all‐cause mortality was associated with chronic obstructive pulmonary disease (COPD) (odds ratio, OR: 7.07, 95% CI 2.75–18.16), chronic heart failure (CHF) (OR: 5.47, 95% CI 1.06–28.31), diabetes mellitus (DM) (OR: 3.30, 95% CI 1.51–7.20) and body mass index (BMI) (increase of 5 kg m−2, OR: 1.44, 95% CI: 1.04–1.99). Chronic upper airway problems were associated with survival (OR: 0.45, 95% CI 0.23–0.90). There were significant interactions between respiratory disturbance index and BMI and COPD. Mortality of patients younger than the median age (62 years) was associated with COPD, DM and an interaction between BMI and apnoea severity. Predictors of mortality for the older patients were COPD, CHF and DM. We conclude that all‐cause mortality in sleep apnoea is associated with co‐morbidities and obesity. Severity of sleep apnoea affects mortality by interacting with obesity and lung disease.
Extensive pollen dispersal in a bird‐pollinated shrub, Calothamnus quadrifidus, in a fragmented landscape
Authors: BYRNE M. , ELLIOTT C. P. , YATES C. , COATES D. J. 
Published: February 2007

AbstractPollen dispersal was investigated in six populations of Calothamnus quadrifidus, a bird‐pollinated shrub in the fragmented agricultural region of southern Western Australia. Paternity analysis using six microsatellite loci identified a pollen source within populations for 67% of seedlings, and the remainder were assumed to have arisen from pollen sources outside the populations. Outcrossing was variable, ranging from 5% to 82%, and long‐distance pollen dispersal was observed in all populations with up to 43% of pollen sourced from outside the populations over distances of up to 5 km. This extensive pollen immigration was positively associated with population size but not isolation. Comparison of two populations of similar size but different density showed greater internal pollination and less selfing in the denser population, suggesting an influence of density on pollinator behaviour. The study revealed extensive long‐distance pollen dispersal for C. quadrifidus within this fragmented agricultural landscape and highlighted the interaction between reserve populations and isolated road verge remnants in maintaining genetic connectivity at the landscape scale.
Distinct patterns of genetic variation in Pristionchus pacificus and Caenorhabditis elegans, two partially selfing nematodes with cosmopolitan distribution
Authors: ZAUNER HANS , MAYER WERNER E. , HERRMANN MATTHIAS , WELLER ANDREAS , ERWIG MIRJA , SOMMER RALF J. 
Published: February 2007

AbstractHermaphroditism has evolved several times independently in nematodes. The model organism Caenorhabditis elegans and Pristionchus pacificus are self‐fertile hermaphrodites with rare facultative males. Both species are members of different families: C. elegans belongs to the Rhabditidae and P. pacificus to the Diplogastridae. Also, both species differ in their ecology: C. elegans is a soil‐dwelling nematode that is often found in compost heaps. In contrast, field studies in Europe and North America indicate that Pristionchus nematodes are closely associated with scarab beetles. In C. elegans, several recent studies have found low genetic diversity and rare out‐crossing events. Little is known about diversity levels and population structure in free‐living hermaphroditic nematodes outside the genus Caenorhabditis. Taking a comparative approach, we analyse patterns of molecular diversity and linkage disequilibrium in 18 strains of P. pacificus from eight countries and four continents. Mitochondrial sequence data of P. pacificus isolates reveal a substantially higher genetic diversity on a global scale when compared to C. elegans. A mitochondrial‐derived hermaphrodite phylogeny shows little geographic structuring, indicating several worldwide dispersal events. Amplified fragment length polymorphism and single strand conformation polymorphism analyses demonstrate a high degree of genome‐wide linkage disequilibrium, which also extends to the mitochondrial genome. Together, these findings indicate distinct patterns of genetic variation of the two species. The low level of genetic diversity observed in C. elegans might reflect a recent human‐associated dispersal, whereas the P. pacificus diversity might reflect a long‐lasting and ongoing insect association. Thus, despite similar lifestyle characteristics in the laboratory, the reproductive mode of hermaphroditism with rare facultative males can result in distinct genetic variability patterns in different ecological settings.