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Studies investigating the underlying mechanisms of hallucinations in patients with schizophrenia suggest that an imbalance in top-down expectations v. bottom-up processing underlies these errors in perception. This study evaluates this hypothesis by testing if individuals drawn from the general population who have had auditory hallucinations (AH) have more misperceptions in auditory language perception than those who have never hallucinated.
We used an online survey to determine the presence of hallucinations. Participants filled out the Questionnaire for Psychotic Experiences and participated in an auditory verbal recognition task to assess both correct perceptions (hits) and misperceptions (false alarms). A hearing test was performed to screen for hearing problems.
A total of 5115 individuals from the general Dutch population participated in this study. Participants who reported AH in the week preceding the test had a higher false alarm rate in their auditory perception compared with those without such (recent) experiences. The more recent the AH were experienced, the more mistakes participants made. While the presence of verbal AH (AVH) was predictive for false alarm rate in auditory language perception, the presence of non-verbal or visual hallucinations were not.
The presence of AVH predicted false alarm rate in auditory language perception, whereas the presence of non-verbal auditory or visual hallucinations was not, suggesting that enhanced top-down processing does not transfer across modalities. More false alarms were observed in participants who reported more recent AVHs. This is in line with models of enhanced influence of top-down expectations in persons who hallucinate.
Fluctuations in the volume and the value of financial remittances received from abroad affect the livelihood of households in developing economies across the world. Yet, political scientists have little to say about how changes in remittances, as opposed to the receipt of remittance payments alone, affect recipients’ political attitudes. Relying on a unique four-wave panel study of Kyrgyz citizens between 2010–2013 and a cross-sectional sample of 28 countries in Central Eastern Europe, the Caucasus and Central Asia, we show that when people experience a decrease (increase) in remittances, they become less (more) satisfied about their household economic situation and misattribute responsibility to the incumbent at home. Our findings advance the literature on the political consequences of remittance payments and suggest that far from exclusively being an international risk-sharing mechanism for developing countries, remittances can also drive fluctuations in incumbent approval and compromise rudimentary accountability mechanisms in the developing world.
The ability to predict upper respiratory infections (URI), lower respiratory infections (LRI), and gastrointestinal tract infections (GI) in independently living older persons would greatly benefit population and individual health. Social network parameters have so far not been included in prediction models. Data were obtained from The Maastricht Study, a population-based cohort study (N = 3074, mean age (±s.d.) 59.8 ± 8.3, 48.8% women). We used multivariable logistic regression analysis to develop prediction models for self-reported symptomatic URI, LRI, and GI (past 2 months). We determined performance of the models by quantifying measures of discriminative ability and calibration. Overall, 953 individuals (31.0%) reported URI, 349 (11.4%) LRI, and 380 (12.4%) GI. The area under the curve was 64.7% (95% confidence interval (CI) 62.6–66.8%) for URI, 71.1% (95% CI 68.4–73.8) for LRI, and 64.2% (95% CI 61.3–67.1%) for GI. All models had good calibration (based on visual inspection of calibration plot, and Hosmer–Lemeshow goodness-of-fit test). Social network parameters were strong predictors for URI, LRI, and GI. Using social network parameters in prediction models for URI, LRI, and GI seems highly promising. Such parameters may be used as potential determinants that can be addressed in a practical intervention in older persons, or in a predictive tool to compute an individual's probability of infections.
The Mema is a semi-arid region in central Mali with a rich archaeological heritage indicating the former existence of large urban settlements. The archaeological data suggest millennia of occupation history of the Méma preceding relatively sudden abandonment by the 14th or 15th century AD. Population numbers have remained low since then and today’s human presence in the area is sparse and largely mobile. Geomorphologically, the Méma can be characterized as a graben hosting various generations of aeolian landforms and (presently mostly dry) interdunal channels and lakes, linked to the neighbouring Inland Niger Delta floodplain. Given this setting, and the variability of the Sahelian climate, climatic contributions to the region’s sudden abandonment are likely. A geomorphological survey of the region, and interpretation of the observed geomorphological record in terms of climatic history, aimed at providing a basis for understanding the intensive occupation and subsequent abandonment of the Méma. The results of this study underscore dramatic Holocene climatic variability, leading to the region’s present geomorphological diversity, but also suggest that neotectonic movements constitute an important additional cause of regional desiccation. Both may have encouraged prehistoric people to abandon the Méma after a long period of occupation.
This study evaluated the psychometric properties of the Strengths and Difficulties Questionnaire Self-Report (SDQ-S) in South African adolescents, and compared findings with data from the UK, Australia and China.
A sample of 3451 South African adolescents in grade 8, the first year of secondary school (Mage = 13.7 years), completed the SDQ-S in Afrikaans, English or isiXhosa. Means, group differences and internal consistency were analysed using SPSS V22, and confirmatory factor analyses were conducted using MPlus V7.
In the South African sample, significant gender differences were found for four of the five sub-scale means and for total difficulties, but gender differences of alpha scores were negligible. The internal consistency for the total difficulties, prosocial behaviour and emotional symptoms sub-scales were fair. UK cut-off values for caseness (set to identify the top 10% of scores in a UK sample) led to a higher proportion of South African adolescents classified in the ‘abnormal’ range on emotional and peer difficulties and a lower proportion classified in the ‘abnormal’ range for hyperactivity. South African cut-offs were therefore generated. The cross-country comparison with UK, Australian and Chinese data showed that South African adolescent boys and girls had the highest mean scores on total difficulties as well as on the subscales of emotional symptoms and conduct problems. In contrast, South African boys and girls had the lowest mean scores for hyperactivity/inattention. The UK boys and girls had the highest mean scores for hyperactivity/inattention, while the Australian sample had the highest scores for prosocial behaviours. The Chinese boys had the highest peer problem mean scores and Chinese boys and girls had the lowest means on prosocial behaviours. Confirmatory factor analyses showed significant item loadings with loadings higher than 0.40 for the emotional and prosocial behaviour sub-scales on the five-factor model, but not for all relevant items on the other three domains.
Findings support the potential usefulness of the SDQ-S in a South African setting, but suggest that the SDQ-S should not be used with UK cut-off values, and indicate the need for further validation and standardisation work in South African adolescents. We recommend that in-country cut-offs for ‘caseness’ should be used for clinical purposes in South Africa, that cross-country comparisons should be made with caution, and that further examination of naturalistic clusters and factors of the SDQ should be performed in culturally and contextually diverse settings.
Many astronomers working in the field of AstroInformatics write code as part of their work. Although the programming language of choice is Python, a small number (8%) use R. R has its specific strengths in the domain of statistics, and is often viewed as limited in the size of data it can handle. However, Microsoft R Server is a product that removes these limitations by being able to process much larger amounts of data. I present some highlights of R Server, by illustrating how to fit a convolutional neural network using R. The specific task is to classify galaxies, using only images extracted from the Sloan Digital Skyserver.
A standardised, national, 160-item FFQ, the FFQ-NL 1.0, was recently developed for Dutch epidemiological studies. The objective was to validate the FFQ-NL 1.0 against multiple 24-h recalls (24hR) and recovery and concentration biomarkers. The FFQ-NL 1.0 was filled out by 383 participants (25–69 years) from the Nutrition Questionnaires plus study. For each participant, one to two urinary and blood samples and one to five (mean 2·7) telephone-based 24hR were available. Group-level bias, correlation coefficients, attenuation factors, de-attenuated correlation coefficients and ranking agreement were assessed. Compared with the 24hR, the FFQ-NL 1.0 estimated the intake of energy and macronutrients well. However, it underestimated intakes of SFA and trans-fatty acids and alcohol and overestimated intakes of most vitamins by >5 %. The median correlation coefficient was 0·39 for energy and macronutrients, 0·30 for micronutrients and 0·30 for food groups. The FFQ underestimated protein intake by an average of 16 % and K by 5 %, relative to their urinary recovery biomarkers. Attenuation factors were 0·44 and 0·46 for protein and K, respectively. Correlation coefficients were 0·43–0·47 between (fatty) fish intake and plasma EPA and DHA and 0·24–0·43 between fruit and vegetable intakes and plasma carotenoids. In conclusion, the overall validity of the newly developed FFQ-NL 1.0 was acceptable to good. The FFQ-NL 1.0 is well suited for future use within Dutch cohort studies among adults.
The gastrointestinal tract (GIT) microbiota has been identified as an important reservoir of antibiotic resistance genes (ARGs) that can be horizontally transferred to pathogenic species. Maternal GIT microbes can be transmitted to the offspring, and recent work indicates that such transfer starts before birth. We have used culture-independent genetic screenings to explore whether ARGs are already present in the meconium accumulated in the GIT during fetal life and in feces of 1-week-old infants. We have analyzed resistance to β-lactam antibiotics (BLr) and tetracycline (Tcr), screening for a variety of genes conferring each. To evaluate whether ARGs could have been inherited by maternal transmission, we have screened perinatal fecal samples of the 1-week-old babies’ mothers, as well as a mother–infant series including meconium, fecal samples collected through the infant’s 1st year, maternal fecal samples and colostrum. Our results reveal a high prevalence of BLr and Tcr in both meconium and early fecal samples, implying that the GIT resistance reservoir starts to accumulate even before birth. We show that ARGs present in the mother may reach the meconium and colostrum and establish in the infant GIT, but also that some ARGs were likely acquired from other sources. Alarmingly, we identified in both meconium and 1-week-olds’ samples a particularly elevated prevalence of mecA (>45%), six-fold higher than that detected in the mothers. The mecA gene confers BLr to methicillin-resistant Staphylococcus aureus, and although its detection does not imply the presence of this pathogen, it does implicate the young infant’s GIT as a noteworthy reservoir of this gene.
The mobilization of culturally rooted issues has altered political competition throughout Western Europe. This article analyzes to what extent the mobilization of immigration issues has affected how people identify with politics. Specifically, it analyzes whether voters’ left/right self-identifications over the past 30 years increasingly correspond to cultural rather than economic attitudes. This study uses longitudinal data from the Netherlands between 1980 and 2006 to demonstrate that as time progresses, voters’ left/right self-placements are indeed more strongly determined by anti-immigrant attitudes than by attitudes towards redistribution. These findings show that the issue basis of left/right identification is dynamic in nature and responsive to changes in the political environment.
In the midst of the economic crisis sweeping across the European continent, popular support for European integration has become a common theme in political discourse. This article revisits the debate regarding popular support for European integration. Although many journalists, politicians and pundits currently argue that the public is becoming increasingly sceptical of further steps towards integration, this study qualifies that claim and suggests that public opinion towards Europe is best described as ambivalent. Also, it shows that ambivalence regarding European integration is higher in Western than in Central and Eastern Europe. This is probably due to the fact that as citizens in Western Europe have gained more experience with the positive and negative consequences of integration over the years, they have also become more ambivalent about the European project. Rather than suggesting that citizens are by and large turning their backs on Europe, I put forward the view that we seem to be witnessing growing uncertainty about the future scope and depth of the integration process. This, I argue, could be viewed as a natural by-product of experiencing both the virtues and the vices association with membership. Consequently, attitude ambivalence as such may be demonstrative of a maturation of public opinion concerning European integration.
Objectives: This study aimed to investigate the technical documentation of manufacturers on issues of safe use of their device in a home setting.
Methods: Three categories of equipment were selected: infusion pumps, ventilators, and dialysis systems. Risk analyses, instructions for use, labels, and post market surveillance procedures were requested from manufacturers. Additionally, they were asked to fill out a questionnaire on collection of field experience, on incidents, and training activities.
Results: Specific risks of device operation by lay users in a home setting were incompletely addressed in the risk analyses. A substantial number of user manuals were designed for professionals, rather than for patients or lay carers. Risk analyses and user information often showed incomplete coherence. Post market surveillance was mainly based on passive collection of field experiences.
Conclusions: Manufacturers of infusion pumps, ventilators, and dialysis systems pay insufficient attention to the specific risks of use by lay persons in home settings. It is expected that this conclusion is also applicable for other medical equipment for treatment at home. Manufacturers of medical equipment for home use should pay more attention to use errors, lay use and home-specific risks in design, risk analysis, and user information. Field experiences should be collected more actively. Coherence between risk analysis and user information should be improved. Notified bodies should address these aspects in their assessment. User manuals issued by institutions supervising a specific home therapy should be drawn up in consultation with the manufacturer.
The need for symmetry and ordering objects related to a “just right”-feeling is a common symptom in Tourette's syndrome (TS) and resembles symmetry behavior in obsessive-compulsive disorder, but its pathophysiology is unknown. We used a symptom provocation paradigm to investigate the neural correlates of symmetry behavior in TS and hypothesized the involvement of frontal-striatal and limbic brain areas.
Pictures of asymmetrically and symmetrically arranged objects were presented in randomized blocks (4 blocks of each condition) to 14 patients with TS and 10 matched healthy controls (HC). A H215O positron emission tomography scan was acquired during each stimulus block, resulting in 8 scans per subject. After each scan, state anxiety and symmetry behavior (the urge to rearrange objects) were measured using a visual analogue scale.
During the asymmetry condition, TS patients showed increased regional cerebral blood flow (rCBF) in the anterior cingulate cortex, supplementary motor area, and inferior frontal cortex, whereas HC showed increased rCBF in the visual cortex, primary motor cortex, and dorsal prefrontal cortex. Symmetry ratings during provocation correlated positively with orbitofrontal activation in the TS group and sensorimotor activation in the HC group, and negatively with dorsal prefrontal activity in HC.
Results suggest that both motor and limbic circuits are involved in symmetry behavior in TS. Motor activity may relate to an urge to move or perform tics, and limbic activation may indicate that asymmetry stimuli are salient for TS patients. In contrast, symmetry provocation in HC resulted in activation of brain regions implicated in sensorimotor function and cognitive control.
Determinants of a child's diet shortly after weaning and lactation have been relatively understudied. The aim of the present study was hence to identify common dietary patterns in toddlers and to explore parental and child indicators of these dietary patterns. The study was a population-based, prospective birth-cohort study in Rotterdam, the Netherlands. Food consumption data of 2420 children aged 14 months were used. A ‘Health conscious’ dietary pattern characterised by pasta, fruits, vegetables, oils, legumes and fish, and a ‘Western-like’ dietary pattern characterised by snacks, animal fats, confectionery and sugar-containing beverages were extracted using principal component analysis. Low paternal education, low household income, parental smoking, multiparity, maternal BMI, maternal carbohydrate intake and television-watching of child were determinants of a ‘Western-like’ diet, whereas parental age, dietary fibre intake during pregnancy, introduction of solids after 6 months and female sex were inversely associated with a ‘Western-like’ diet of the child. Maternal co-morbidity, alcohol consumption during pregnancy and female sex were inversely associated with a ‘Health conscious’ dietary pattern of the child, while single parenthood, folic acid use and dietary fibre intake during pregnancy were positively associated. All aforementioned associations were statistically significant. In conclusion, both ‘Western-like’ and ‘Health conscious’ diets can already be identified in toddlers. Particularly, adherence to a ‘Western-like’ diet is associated with unfavourable lifestyle factors of the parents and child, and low socio-economic background. These findings can form a basis for future epidemiological studies regarding dietary patterns and health outcomes in young children.
During the 1980s and the 1990s, the elites of the two largest Dutch parties converged dramatically in debates on income redistribution, nuclear power and the overall Left–Right dimension, paving the way for the Dutch party system's polarization on immigration and cultural issues. Did the Dutch mass public depolarize along with party elites, and, if so, was this mass-level depolarization confined to affluent, educated, politically engaged citizens? Analysis of Dutch Parliamentary Election Study respondents’ policy beliefs and partisan loyalties in 1986–98 shows that the mass public depolarized during this period, and that this extended equally throughout the electorate. These conclusions mirror previous findings on Britain, but differ from those on the United States, and have important implications for political representation and for parties’ election strategies.
To assess genotype adaptability to variable environments, we evaluated five irrigated rice genotypes, three new varieties, WAS161, a NERICA, IR32307 and ITA344, and two controls: Sahel 108, the most popular short-duration variety in the region, and IR64. In a field experiment conducted at two locations, Ndiaye and Fanaye, along the Senegal River, rice was sown on 15 consecutive dates at one month intervals starting in February 2006. Yield (0–12.2 t ha−1) and crop cycle duration (117–190 days) varied with sowing date, genotype and site. Rice yield was very sensitive to sowing date and the associated temperature regimes. Spikelet sterility due to cold stress (T < 20 °C) was observed when the crops were sown in August (Ndiaye), September (Ndiaye and Fanaye) and October (Ndiaye and Fanaye), and heat stress (T > 35 °C) resulted in spikelet sterility when sowing took place in April (Ndiaye and Fanaye) and May (Fanaye). For all experiments the source and sink balance was quantified and showed that yield was most limited by sink size when sowing between July and October. Variety WAS 161 was least affected by genotype × environment interactions, resulting in lower interactive principal component values. An increase in minimum temperature of 3 °C could decrease spikelet sterility from 100 to 45%. These changes in temperature are likely to force rice farmers in the Senegal River to adjust the cropping calendar, e.g. to delay planting or to use heat-tolerant genotypes.
Neospora caninum is an Apicomplexan protozoan that has the dog as a definitive host and cattle (among other animals) as intermediate hosts. It causes encephalopathy in dogs and abortion in cows, with significant loss in worldwide livestock. As any Apicomplexan, the parasite invades the cells using proteins contained in the phylum-specific organelles, like the micronemes, rhoptries and dense granules. The aim of this study was the characterization of a homologue (denominated NcMIC2-like1) of N. caninum thrombospondin-related anonymous protein (NcMIC2), a micronemal protein previously shown to be involved in the attachment and connection with the intracellular motor responsible for the active process of invasion. A polyclonal antiserum raised against the recombinant NcMIC2-like1 functional core (thrombospondin and integrin domains) recognized the native form of NcMIC2-like1, inhibited the in vitro invasion process and localized NcMIC2-like1 at the apical complex of the parasite by confocal immunofluorescence, indicating its micronemal localization. The new molecule, NcMIC2-like1, has features that differentiates it from NcMIC2 in a substantial way to be considered a homologue†.
The effect of oral administration of antibiotics on the intestinal flora of conventional mice and their resistance to colonization by orally introduced Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa was studied. Colonization resistance (CR) was expressed as the log of the oral bacterial dose followed by a persistent take in 50 % of the contaminated animals. The intestinal flora was virtually eliminated by the antibiotics and this elimination was accompanied by a precipitous fall of CR. CR gradually returned to normal values during the period of repopulation of the intestinal tract by the organisms surviving the treatment. Antibiotic treatment resulted in the disappearance of Enterobacteriaceae, enterococci, staphylococci and yeasts and, under appropriate housing conditions, the animals remained free of these organisms indefinitely. Germ-free mice contaminated with the intestinal flora of an antibiotic-treated animal and their offspring housed in a germ-free isolator showed high values of CR. Their intestinal flora consisted of anaerobic bacteria only. Apparently, these anaerobes are responsible for CR in these and in conventional mice.
After oral contamination of conventional mice with high doses of Escherichia coli, Klebsiella pneumoniae or Pseudomonas aeruginosa the contaminant was recovered in abnormally high concentrations from the duodenum and caecum during the first few days. In this initial colonization phase, evidence of spread was obtained by culturing the cervical and mesenteric lymph nodes and spleen. Longer after contamination the intestinal concentration decreased to normal and spread stopped. In orally antibiotic-treated mice, the situation seen during the initial colonization phase in conventional mice occurred after a much lower oral contamination dose and persisted during the entire observation period of 2 weeks.
Seed predation is an important component of seed mortality of weeds in agro-ecosystems, but the agronomic use and management of this natural weed suppression is hampered by a lack of insight in the underlying ecological processes. In this paper, we investigate whether and how spatial and temporal variation in activity-density of granivorous ground beetles (Coleoptera: Carabidae) results in a corresponding pattern of seed predation. Activity-density of carabids was measured by using pitfall traps in two organic winter wheat fields from March to July 2004. Predation of seeds (Capsella bursa-pastoris, Lamium amplexicaule, Poa annua and Stellaria media) was assessed using seed cards at the same sites and times. As measured by pitfall traps, carabids were the dominant group of insects that had access to the seed cards. In the field, predation of the four different species of seed was in the order: C. bursa-pastoris>P. annua>S. media>L. amplexicaule; and this order of preference was confirmed in the laboratory using the dominant species of carabid. On average, seed predation was higher in the field interior compared to the edge, whereas catches of carabids were highest near the edge. Weeks with elevated seed predation did not concur with high activity-density of carabids. Thus, patterns of spatial and temporal variation in seed predation were not matched by similar patterns in the abundance of granivorous carabid beetles. The lack of correspondence is ascribed to effects of confounding factors, such as weather, the background density of seeds, the composition of the carabid community, and the phenology and physiological state of the beetles. Our results show that differences in seed loss among weed species may be predicted from laboratory trials on preference. However, predator activity-density, as measured in pitfall traps, is an insufficient predictor of seed predation over time and space within a field.
The aim of this study was to describe a systematic process of record-linkage, cross-validation, case-ascertainment and capture–recapture analysis to assess the quality of tuberculosis registers and to estimate the completeness of notification of incident tuberculosis cases in The Netherlands in 1998. After record-linkage and cross-validation 1499 tuberculosis patients were identified, of whom 1298 were notified, resulting in an observed under-notification of 13·4%. After adjustment for possible imperfect record-linkage and remaining false-positive hospital cases observed under-notification was 7·3%. Log-linear capture–recapture analysis initially estimated a total number of 2053 (95% CI 1871–2443) tuberculosis cases, resulting in an estimated under-notification of 36·8%. After adjustment for possible imperfect record-linkage and remaining false-positive hospital cases various capture–recapture models estimated under-notification at 13·6%. One of the reasons for the higher than expected estimated under-notification in a country with a well-organized system of tuberculosis control might be that some tuberculosis cases, e.g. extrapulmonary tuberculosis, are managed by clinicians less familiar with notification of infectious diseases. This study demonstrates the possible impact of violation of assumptions underlying capture–recapture analysis, especially the perfect record-linkage, perfect positive predictive value and absent three-way interaction assumptions.