To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure firstname.lastname@example.org
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Breast-feeding is thought to facilitate young children’s acceptance of new foods, including vegetables, but the evidence for this relationship appears inconsistent across studies. Increasing children’s vegetable intake remains challenging; therefore the present study aimed to investigate whether breast-feeding duration predicts vegetable intake in 2–6-year-old children.
Actual vegetable intake was measured in studies across three European countries. General linear model analyses with breast-feeding duration, sex and age of the child and maternal education as variables were used to predict children’s vegetable intake per country. Additionally, the relationships between child eating behaviour characteristics (asked through the Child Eating Behaviour Questionnaire) and vegetable intake were investigated via Pearson correlations.
Daycare centres, schools and home settings in Denmark, Greece and the Netherlands.
Children aged 2–6 years (n 750).
Breast-feeding duration was positively associated with children’s vegetable intake at 2–6 years old in Denmark (P<0·01) and the Netherlands (P<0·05), but not in Greece (P=0·17). Age of the child, maternal education and sex of the child did not predict vegetable intake in our sample. All countries showed an inverse relationship between food neophobia and children’s vegetable intake and a positive relationship between vegetable liking and intake.
The present study found that breast-feeding duration is a predictor of later vegetable intake, but that current child eating behaviour characteristics, such as vegetable liking, food neophobia and enjoyment of food, also influence vegetable intake. Besides encouragement of breast-feeding duration, strategies that support vegetable liking and food enjoyment and decrease food neophobia are needed to support young children’s vegetable intake.
We study the geometric and topological properties of strange non-chaotic attractors created in non-smooth saddle-node bifurcations of quasiperiodically forced interval maps. By interpreting the attractors as limit objects of the iterates of a continuous curve and controlling the geometry of the latter, we determine their Hausdorff and box-counting dimension and show that these take distinct values. Moreover, the same approach allows us to describe the topological structure of the attractors and to prove their minimality.
Measles, mumps, rubella (MMR) and varicella zoster virus (VZV) infection can cause serious diseases and complications in the HIV-positive population. Due to successful vaccination programmes measles, mumps and congenital rubella syndrome has become neglected in Germany. However, recent outbreaks of measles have occurred from import-associated cases. In this cross-sectional study the serostatus for MMR and VZV in 2013 HIV-positive adults from three different university outpatient clinics in Bonn (n = 544), Cologne (n = 995) and Munich (n = 474) was analysed. Sera were tested for MMR- and VZV-specific immunglobulin G antibodies using commercial immunoassays. Seronegativity was found in 3% for measles, 26% for mumps, 11% for rubella and 2% for VZV. Regarding MMR, 35% of patients lacked seropositivity against at least one infectious agent. In multivariable analysis younger age was strongly associated with seronegativity against all four viruses, measles, mumps, rubella (P < 0·001, P < 0·001 and P = 0·001, respectively) and VZV (P = 0·001). In conclusion, there is high need for MMR and VZV vaccination in people living with HIV in Germany born in 1970 or later. Thus, systematic MMR and VZV antibody screening and vaccination should be implemented in the HIV-positive population to prevent serious disease and complications of vaccine-preventable diseases.
Approximately half of the variation in wellbeing measures overlaps with variation in personality traits. Studies of non-human primate pedigrees and human twins suggest that this is due to common genetic influences. We tested whether personality polygenic scores for the NEO Five-Factor Inventory (NEO-FFI) domains and for item response theory (IRT) derived extraversion and neuroticism scores predict variance in wellbeing measures. Polygenic scores were based on published genome-wide association (GWA) results in over 17,000 individuals for the NEO-FFI and in over 63,000 for the IRT extraversion and neuroticism traits. The NEO-FFI polygenic scores were used to predict life satisfaction in 7 cohorts, positive affect in 12 cohorts, and general wellbeing in 1 cohort (maximal N = 46,508). Meta-analysis of these results showed no significant association between NEO-FFI personality polygenic scores and the wellbeing measures. IRT extraversion and neuroticism polygenic scores were used to predict life satisfaction and positive affect in almost 37,000 individuals from UK Biobank. Significant positive associations (effect sizes <0.05%) were observed between the extraversion polygenic score and wellbeing measures, and a negative association was observed between the polygenic neuroticism score and life satisfaction. Furthermore, using GWA data, genetic correlations of -0.49 and -0.55 were estimated between neuroticism with life satisfaction and positive affect, respectively. The moderate genetic correlation between neuroticism and wellbeing is in line with twin research showing that genetic influences on wellbeing are also shared with other independent personality domains.
The aim of this study was to evaluate the quality of life in patients with vascular chronic Q fever at time of diagnosis and during follow-up. Based upon the SF-36 questionnaire, the mean physical and mental health of each patient were assessed at 3-month intervals for up to 18 months. A total of 26 patients were included in the study. At time of diagnosis, the mean physical health and mental health score was 50·6 [95% confidence interval (CI) 46·7–54·4] and 44·6 (95% CI 41·6–47·5), respectively. During treatment, the mean physical health score declined significantly by 1·7 points each 3 months (P < 0·001) to 40·8 (95% CI 34·4–45·1). The mean mental health score significantly and steadily increased towards 51·2 (95% CI 46·9–54·3) during follow-up (P = 0·026). A total of 23% of patients were cured after 18 months of follow-up. In conclusion, quality of life at time of diagnosis for patients with vascular chronic Q fever is lower compared to a similar group of patients, matched for age and gender, with an aortic abdominal aneurysmal disease, and physical health decreases further after starting treatment. Considering the low percentage of cure, the current treatment of vascular chronic Q fever patients may require a separate strategy from that of endocarditis in order to increase survival.
Polycyclic aromatic hydrocarbon (PAH) molecules have been long considered promising candidates for the carriers of the diffuse interstellar bands (DIBs). The PAH-DIB hypothesis, however, raises two major issues. First, the number of interstellar PAH species is potentially orders of magnitude larger than the number of DIBs. Second, the absorption spectrum of a PAH is in general dominated by bands found at UV wavelengths while, conversely, DIBs are absent from the UV wavelength domain and arise at visible and near IR wavelengths. These issues do not necessarily weaken the PAH-DIB hypothesis and can actually allow us to refine it. In that context, we analyze the UV/vis absorption spectra of PAH molecules isolated in Ne matrices and propose that polyynyl-substituted PAHs, or similar species, are valid candidates for the carriers of the DIBs. Finally, a possible lifecycle for DIB-carrying PAHs is presented.
The electronic spectroscopy of various polycyclic aromatic hydrocarbon (PAH) molecules has been studied in the laboratory at low temperatures using both molecular beam and matrix isolation spectroscopy techniques. While molecular beam spectra can be readily compared to astronomical observations, the band positions measured in Ne and Ar matrices are extrapolated to obtain rather good estimates for the same transitions in the gas phase. Absolute absorption cross sections are determined for gas-phase and matrix spectra by comparing them with calibrated solution spectra. All laboratory results are analyzed and discussed in view of the role that PAHs can play as carriers of the diffuse interstellar bands (DIBs). Our studies suggest that regular neutral PAHs are not responsible for any of the known strong DIBs.
This study examines historical variation in individual trajectories of heavy drinking and marijuana use from age 18 to 22. Unlike most studies that have examined cohort differences in drug use, it focuses on differences in both level of use and rates of change (growth). Nearly 39,000 youths from the high school classes of 1976–2004 were surveyed at biennial intervals between the ages of 18 and 22 as part of the national Monitoring the Future study. Between 1976 and 2004, adolescent heavy drinking decreased substantially. However, because the age 18–22 heavy drinking growth rate increased threefold for males and sixfold for females during this period, heavy drinking among 21- to 22-year-olds remained largely stable. The growth rate for marijuana use was more stable across cohorts, and historical declines in use were sizable across the entire 18–22 age band. Generally, historical variation in use was unrelated to college status and living arrangements as well as to historical changes in the distribution of young adult social roles. Findings suggest that historical fluctuations in use were less the result of proximal young adult factors and more the result of historical variation in distal adolescent factors, the effect of which diminished with age, especially for heavy drinking.
Of eight acute infections in German tourists caused by sandfly fever virus, serotype Toscana (TOS). and diagnosed clinically and serologically, seven were acquired during visits to Tuscany, Italy, and one to Coimbra, Portugal. An indirect immunofluorescence assay (IFA) using infected cells, and a newly developed enzyme-immunoassay (EIA) using crude virus antigen prepared from infected Vero-E6 cells was used to detect anti-TOS IgM and IgG. In a seroepidemiological survey of 859 health care workers and medical students, anti-TOS IgG was detected in 1·0% by IFA, and in 0·7% by EIA. In 2034 German patients hospitalized for various diseases, 1·6% were positive for anti-TOS IgG by IFA, and 0·8% by EIA. Anti-TOS IgG was detected in 43 samples of commercial immunoglobulins at titres of 10–1000 by EIA. Although the seroprevalence of antibodies to TOS is low in Germany, TOS infection should be considered in patients returning from endemic areas who complain of fever, and headaches, and have symptoms of meningitis.
Effective infection control measures during norovirus outbreaks are urgently needed in places where vulnerable individuals gather. In the present study, the effect of a number of measures was investigated in daily practice. Forty-nine Dutch nursing homes were monitored prospectively for norovirus outbreaks during two winter seasons. A total of 37 norovirus outbreaks were registered. Control measures were most effective when implemented within 3 days after onset of disease of the first patient. Measures targeted at reduced transmission between persons, via aerosols, and via contaminated surfaces reduced illness in staff and in residents. Reducing illness in staff results in fewer costs for sick leave and substitution of staff and less disruption in the care of residents. The effect of control measures on outbreak duration was limited. This is the first intervention study examining the effect of control measures. Further research is needed to extend and refine the conclusions.
The aim of the investigation was to study the influence of indenter tip geometry on the conventionally obtained indentation modulus of enamel by nanoindentation. Indentation tests on bovine enamel using three different diamond pyramidal indenters with half face angles 65.27°, 45°, and 35.26° were conducted to evaluate the indentation modulus using the Oliver–Pharr method [W.C. Oliver and G.M. Pharr, J. Mater. Res.7, 1564 (1992)]. In addition, three different dehydration conditions were studied: wet under Hank's balanced salt solution, laboratory dried, and vacuum dehydrated. For the Berkovich indenter (65.27°) and 45° pyramidal indenters, there was only a small difference between indentation modulus values, whereas for the cube-corner indenter (35.26°) a ratio of 2.4 between laboratory dry and wet samples was found. A detailed evaluation, including indentation creep and recovery as well as pileup, resulted in a reduction of this latter ratio to 1.7. This still large difference was rationalized on the basis of the different deformation mechanisms generated by indenters of different face angles.
A large number of studies, reviews and meta-analyses have reported cognitive deficits in ecstasy users. However most ecstasy users are polydrug users, and therefore it cannot be excluded that these deficits are (partly) the result of drugs other than ecstasy. The current study, part of the Netherlands XTC Toxicity (NeXT) study, investigates the specific sustained effects of ecstasy relative to amphetamine, cocaine and cannabis on the brain using neuropsychological examination.
A stratified sample of 67 subjects with such a variation in type and amount of drug use was included that correlations between the consumption of the various drugs were relatively low allowing stepwise linear multiple regression analyses to differentiate between the effects of ecstasy and those of other substances. Subjects were assessed with neuropsychological tests measuring attention, working memory, verbal and visuospatial memory, and visuospatial ability.
Ecstasy use [mean 327 (s.d.=364) tablets in lifetime] had a specific significant dose-related negative effect on verbal delayed recall after adjusting for the use of other drugs.
These findings strongly suggest a specific sustained negative effect of ecstasy use on verbal memory. The clinical relevance is not immediately clear, because test performance generally remained within the normal range. However the magnitude of the effect is substantial (d>0.5) and long-term consequences cannot be excluded.
To take advantage of the exceptional seeing above the boundary layer
on Antarctic sites, a high-resolution telescope must be mounted on a
support tower. An open transparent tower of framework minimizes the
upward temperature-disturbed airflow. A typical minimum height is
30 m. The tower platform has to be extremely stable against
wind-induced rotational motions, which have to be less than
fractions of an arc second, unusually small from a mechanical
engineering viewpoint. In a traditional structure, structural
deflections result in angular deflections of the telescope platform,
which introduce tip and tilt motions in the telescope. However, a
structure that is designed to deflect with parallel motion relative
to the horizontal plane will undergo solely translation deflections
in the telescope platform and thus will not degrade the image. The
use of a parallel motion structure has been effectively demonstrated
in the design of the 15-m tower for the Dutch Open Telescope (DOT)
on La Palma. Special framework geometries are developed, which make
it possible to construct high towers in stories having platforms
with extreme stability against wind-induced tilt. These geometric
solutions lead to constructions, being no more massive than a normal
steel framework carrying the same load. Consequently, these
lightweight towers are well suited to difficult sites as on
Antarctica. A geometry with 4 stories has been worked out.
In 2002, in The Netherlands a national study of gastroenteritis outbreaks was performed. Epidemiological information was collected by the Public Health Services (PHS) and the Food Inspection Services (FIS) using standardized questionnaires. Stool samples were collected for diagnostic testing. For foodborne outbreaks, food samples were taken. In total, 281 gastroenteritis outbreaks were included, mainly from nursing homes and homes for the elderly (57%), restaurants (11%), hospitals (9%) and day-care centres (7%). Direct person-to-person spread was the predominant transmission route in all settings (overall 78%), except for restaurant outbreaks where food was suspected in almost 90% (overall in 21% of outbreaks). The most common pathogen was norovirus (54%), followed by Salmonella spp. (4%), rotavirus group A (2%), Campylobacter spp. (1%) and only incidentally others. In conclusion, most outbreaks were reported from health and residential institutions, with norovirus as the dominant agent. Control should aim at reducing person-to-person spread. In foodborne outbreaks norovirus was common, due to contamination of food by food handlers. Salmonella, as the second foodborne pathogen, was mainly associated with raw shell eggs. These results stress the continuous need for food safety education, complementary to governmental regulation.
We compared gastroenteritis cases that consulted a general practitioner (GP) with those who did not in a community-based study and also with those in a GP-based study. We aimed to identify factors associated with consultation, and with inclusion of cases by GPs, and secondly to study the effects on the frequency of detection of pathogens. Furthermore, we estimated the under-ascertainment by GPs. Both studies were performed in The Netherlands in the same population in an overlapping time-period. Overall, 5% of community cases consulted a GP. Cases who consulted suffered from more severe episodes than non-consulting cases. Inclusion of cases by GPs, instead of a study team, caused a selection of more severe cases with more chronic symptoms. When extrapolating data from GP-based studies, it should be taken into account that, in general practice, gastroenteritis due to bacteria and Giardia lamblia is a relatively large proportion of that in the community and gastroenteritis due to Norwalk-like viruses is a relatively small proportion. The incidence of gastroenteritis in general practices was estimated between 14 and 35 per 1000 person years.
DNA was extracted from specimens derived from the calcaneus of the Tyrolean Ice Man under
sterile conditions in a laboratory, where no DNA extractions and PCR experiments had been
performed before. Agarose gel electrophoresis and ethidium bromide staining did not reveal any
evidence of genomic DNA in the preparation obtained, indicating a high degree of DNA degradation.
Nevertheless, we performed PCR amplifications with this sample using primer pairs specific for HLA
class II alleles. HLA-DRB and DQB1 alleles were amplified in a nested PCR approach. In one of the
reactions, we observed a distinct amplification product, which we directly sequenced. By comparing
the obtained nucleotide sequence with a database of HLA alleles we assigned the HLA-DRB1*1402
type to the amplified sample. None of the investigators involved possesses this allele, indicating that
no contamination with modern DNA had occured. The HLA-DRB1*1402 allele is extremely rare in
Europe, but is common in Inuits and South American Indians and has previously only once been
identified in the laboratory.
The design of a novel spectrometer based on a thin film diode in combination with an electro statically tunable micro machined mirror will be presented. The semi transparent diode is introduced into a standing wave created in front of a reflector to sample the profile of the standing wave. Varying the position of the reflector results in a shift of the phase of the standing waves and thus in a change of the optical generation profile within the detector. The spectral information of the incoming light can be determined by the Fourier transformation of the transient response of the sensor. An analytical optical model will be presented which facilitates the evaluation of different detector concepts. The model will be applied to discuss different device designs regarding the resolution of the spectrometer, the spectral range and the linearity.
We have investigated microstructural properties of GaAs:N and GaN:As layers using transmission electron microscopy. The samples were grown onto (001)-oriented GaAs substrates by RF-plasma assisted molecular beam epitaxy. It has been found that during the GaAs/GaAs:N epitaxial growth the supplied active nitrogen atoms gave rise to nanometer-size GaN crystallites formed in the GaAs matrix. In addition, silicon incorporation showed abnormal behavior at the two interfaces of the thin GaAs:N layer embedded in GaAs. A model is proposed for the formation of GaN crystallites in GaAs during the growth. In the GaN:As growth, the layer exhibited columnar growth, resulting in domains with different crystallographic orientation. With an increase of the film thickness, the zincblende structure changed to the wurtzite phase of GaN. The distribution of arsenic through the layer thickness was found to be inhomogeneous and be much higher near the GaN/GaAs interface compared to the region near the surface.