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Due to differences in the circulation of influenza viruses, distribution and antigenic drift of A subtypes and B lineages, and susceptibility to infection in the population, the incidence of symptomatic influenza infection can vary widely between seasons and age-groups. Our goal was to estimate the symptomatic infection incidence in the Netherlands for the six seasons 2011/2012 through 2016/2017, using Bayesian evidence synthesis methodology to combine season-specific sentinel surveillance data on influenza-like illness (ILI), virus detections in sampled ILI cases and data on healthcare-seeking behaviour. Estimated age-aggregated incidence was 6.5 per 1000 persons (95% uncertainty interval (UI): 4.7–9.0) for season 2011/2012, 36.7 (95% UI: 31.2–42.8) for 2012/2013, 9.1 (95% UI: 6.3–12.9) for 2013/2014, 41.1 (95% UI: 35.0–47.7) for 2014/2015, 39.4 (95% UI: 33.4–46.1) for 2015/2016 and 27.8 (95% UI: 22.7–33.7) for season 2016/2017. Incidence varied substantially between age-groups (highest for the age-group <5 years: 23 to 47/1000, but relatively low for 65+ years: 2 to 34/1000 over the six seasons). Integration of all relevant data sources within an evidence synthesis framework has allowed the estimation – with appropriately quantified uncertainty – of the incidence of symptomatic influenza virus infection. These estimates provide valuable insight into the variation in influenza epidemics across seasons, by virus subtype and lineage, and between age-groups.
We use the upper 81 mof the record of stable isotopes of water from a 122m long ice core from Lomonosovfonna, central Spitsbergen, Svalbard, to construct an ice-core chronology and the annual accumulation rates over the icefield. the isotope cycles are counted in the ice-core record using a model that neglects short-wavelength and low-amplitude cycles. We find approximately the same number of δ18O cycles as years between known reference horizons, and assume these cycles represent annual cycles. Testing the validity of this assumption using cycles in δD shows that both records give similar numbers of cycles. Using the δ18O chronology, and decompressing the accumulation records using the Nye flow model, we calculate the annual accumulation for the ice-core site back to AD 1715. We find that the average accumulation rate from 1715 to 1950 was on average 0.30 mw.e. Accumulation rates increased about 25% during the later part of the 20th century to an average of 0.41 mw.e. for the period 1950–97. the accumulation rates show highly significant 2.1 and 21 year periodicities, which gives credibility to our time-scale.
We show that it is possible to extract a high-resolution (annual) paleoclimate record from the surface of a blue-ice area (BIA). The variability of the surface stable-isotope values suggests that almost all the surface ice in Scharffenbergbotnen BIA, East Antarctica, is of Holocene age. The isotopic changes across the BIA show that the modern climate there is warmer than the climate in the early-Holocene optimum (11 kyr BP). A volume-conserving ice flow model for the BIA constrained by isotopic variability and layer thicknesses, and a series of 14C ages indicate both that the BIA has been smaller than now, and that the surface velocities were considerably smaller during the Last Glacial Maximum. Changes in ice-sheet thickness drive the BIA towards present-day conditions. The relatively young age of the majority of the BIA also explains the lack of meteorite finds in this area, and may be typical for many BIAs in low-elevation nunatak areas.
Extinctions have altered island ecosystems throughout the late Quaternary. Here, we review the main historic drivers of extinctions on islands, patterns in extinction chronologies between islands, and the potential for restoring ecosystems through reintroducing extirpated species. While some extinctions have been caused by climatic and environmental change, most have been caused by anthropogenic impacts. We propose a general model to describe patterns in these anthropogenic island extinctions. Hunting, habitat loss and the introduction of invasive predators accompanied prehistoric settlement and caused declines of endemic island species. Later settlement by European colonists brought further land development, a different suite of predators and new drivers, leading to more extinctions. Extinctions alter ecological networks, causing ripple effects for islands through the loss of ecosystem processes, functions and interactions between species. Reintroduction of extirpated species can help restore ecosystem function and processes, and can be guided by palaeoecology. However, reintroduction projects must also consider the cultural, social and economic needs of humans now inhabiting the islands and ensure resilience against future environmental and climate change.
An analysis is presented which allows the engineer to quantitatively estimate the validity bounds of aerodynamic methods based in linear potential flows a-priori. The development is limited to quasi-steady planar flows with attached shocks and small body curvature. Perturbation velocities are parameterised in terms of Mach number and flow turning angle by means of a series-expansion for flow velocity based in the method of characteristics. The parameterisation is used to assess the magnitude of non-linear term-groupings relative to linear groups in the full potential equation. This quantification is used to identify dominant nonlinear terms and to estimate the validity of linearising the potential flow equation at a given Mach number and flow turning angle. Example applications include the a-priori estimation of the validity bounds for linear aerodynamic models for supersonic aeroelastic analysis of lifting surfaces and panels.
In search of empirical classifications of depression and anxiety, most subtyping studies focus solely on symptoms and do so within a single disorder. This study aimed to identify and validate cross-diagnostic subtypes by simultaneously considering symptoms of depression and anxiety, and disability measures.
A large cohort of adults (Lifelines, n = 73 403) had a full assessment of 16 symptoms of mood and anxiety disorders, and measurement of physical, social and occupational disability. The best-fitting subtyping model was identified by comparing different hybrid mixture models with and without disability covariates on fit criteria in an independent test sample. The best model's classes were compared across a range of external variables.
The best-fitting Mixed Measurement Item Response Theory model with disability covariates identified five classes. Accounting for disability improved differentiation between people reporting isolated non-specific symptoms [‘Somatic’ (13.0%), and ‘Worried’ (14.0%)] and psychopathological symptoms [‘Subclinical’ (8.8%), and ‘Clinical’ (3.3%)]. Classes showed distinct associations with clinically relevant external variables [e.g. somatization: odds ratio (OR) 8.1–12.3, and chronic stress: OR 3.7–4.4]. The Subclinical class reported symptomatology at subthreshold levels while experiencing disability. No pure depression or anxiety, but only mixed classes were found.
An empirical classification model, incorporating both symptoms and disability identified clearly distinct cross-diagnostic subtypes, indicating that diagnostic nets should be cast wider than current phenomenology-based categorical systems.
Atmospheric Δ14CO2 measurements are useful to investigate the regional signals of anthropogenic CO2 emissions, despite the currently scarce observational network for Δ14CO2. Plant samples are an easily attainable alternative, which have been shown to work well as a qualitative measure of the atmospheric Δ14CO2 signals integrated over the time a plant has grown. Here, we present the 14C analysis results for 89 individual maize (Zea mays) plant samples from 51 different locations that were gathered in the Netherlands in the years 2010 to 2012, and from western Germany and France in 2012. We describe our sampling strategy and results, and include a comparison to a model simulation of the Δ14CO2 that would be accumulated in each plant over a growing season. Our model simulates the Δ14CO2 signatures in good agreement with observed plant samples, resulting in a root-mean-square deviation (RMSD) of 3.30‰. This value is comparable to the measurement uncertainty, but still relatively large (20–50%) compared to the total signal. It is also comparable to the spread in Δ14CO2 values found across multiple plants from a single site, and to the spread found when averaging across larger regions. We nevertheless find that both measurements and model capture the large-scale (>100 km) regional Δ14CO2 gradients, with significant observation-model correlations in all three countries in which we collected samples. The modeled plant results suggest that the largest gradients found in the Netherlands and Germany are associated with emissions from energy production and road traffic, while in France, the 14CO2 enrichment from nuclear sources dominates in many samples. Overall, the required model-based interpretation of plant samples adds additional uncertainty to the already relatively large measurement uncertainty in Δ14CO2, and we suggest that future fossil fuel monitoring efforts should prioritize other strategies such as direct atmospheric sampling of CO2 and Δ14CO2.
The perception of healthy growth and weight may differ between cultures, which could influence feeding practises and consequently affect the development of overweight. The present study examined ethnic variation in maternal perceptions of growth and their influence on feeding practises among Turkish and Dutch infants aged 0–6 months. Data were obtained from the mothers of 143 Turkish and 143 Dutch healthy, singleton, term infants with birth weights appropriate for gestational age, using structured interviews at 1, 4 and 6 months after birth. Compared with Dutch mothers, mothers of Turkish descent perceived a chubby infant more often as pretty (43 v. 22 %), and were more often worried about their infant's growth (13 v. 4 %). Turkish mothers were more likely to give full breast-feeding (BF) until at least 6 months (adjusted OR (aOR) 2·1, 95 % CI 1·0, 4·3) and to start introducing complementary feeding, including rice flour porridge, at the age of 6 months (aOR 2·4, 95 % CI 1·1, 4·9). Infants of Turkish descent were fed on average one milk feeding more during the day and, if introduced to complementary foods before 6 months, were more often given uncommon types of foods (e.g. yogurt and cookies) (aOR 2·1, 95 % CI 1·1, 4·3). The differences in perceptions affected differences in feeding practises only to a small extent. Preventive advice offered to Turkish mothers in Child Health Care should include discussing choices of complementary foods and frequency of feeding from an early age onwards. In Dutch mothers, support for the continuation of BF remains an important issue.
The epidemiology of seasonal influenza is influenced by age. During the influenza season, the European Influenza Surveillance Network (EISN) reports weekly virological and syndromic surveillance data [mostly influenza-like illness (ILI)] based on national networks of sentinel primary-care providers. Aggregated numbers by age group are available for ILI, but not linked to the virological data. At the end of the influenza season 2012/2013, all EISN laboratories were invited to submit a subset of their virological data for this season, including information on age. The analysis by age group suggests that the overall distribution of circulating (sub)types may mask substantial differences between age groups. Thus, in cases aged 5–14 years, 75% tested positive for influenza B virus whereas all other age groups had an even distribution of influenza A and B viruses. This means that the intepretation of syndromic surveillance data without age group-specific virological data may be misleading. Surveillance at the European level would benefit from the reporting of age-specific influenza data.
The association between childhood trauma and psychotic and depressive symptomatology is well established. However, less is known about the specificity and course of these symptoms in relation to childhood trauma.
In a large sample (n = 2765) of patients with psychosis (n = 1119), their siblings (n = 1057) and controls (n = 589), multivariate (mixed-effects) regression analyses with multiple outcomes were performed to examine the association between childhood trauma and psychotic and depressive symptomatology over a 3-year period.
A dose–response relationship was found between childhood trauma and psychosis. Abuse was more strongly associated with positive symptoms than with negative symptoms whereas the strength of the associations between neglect and positive and negative symptoms was comparable. In patients, similar associations between childhood trauma and psychotic or depressive symptoms were found, and in siblings and controls, stronger associations were found between trauma and depressive symptomatology. Childhood trauma was not related to a differential course of symptoms over a 3-year time period.
In congruence with earlier work, our findings suggest that childhood trauma, and abuse in particular, is associated with (subthreshold) psychosis. However, childhood trauma does not seem to be associated with a differential course of symptoms, nor does it uniquely heighten the chance of developing (subthreshold) psychotic symptomatology. Our results indicate that trauma may instead contribute to a shared vulnerability for psychotic and depressive symptoms.
There is an increasing interest in cognitive–behavioural therapy (CBT) interventions targeting negative symptoms in schizophrenia. To date, CBT trials primarily focused on positive symptoms and investigated change in negative symptoms only as a secondary outcome. To enhance insight into factors contributing to improvement of negative symptoms, and to identify subgroups of patients that may benefit most from CBT directed at ameliorating negative symptoms, we reviewed all available evidence on these outcomes.
A systematic search of the literature was conducted in PsychInfo, PubMed and the Cochrane register to identify randomized controlled trials reporting on the impact of CBT interventions on negative symptoms in schizophrenia. Random-effects meta-analyses were performed on end-of-treatment, short-term and long-term changes in negative symptoms.
A total of 35 publications covering 30 trials in 2312 patients, published between 1993 and 2013, were included. Our results showed studies’ pooled effect on symptom alleviation to be small [Hedges’ g = 0.093, 95% confidence interval (CI) −0.028 to 0.214, p = 0.130] and heterogeneous (Q = 73.067, degrees of freedom = 29, p < 0.001, τ2 = 0.081, I2 = 60.31) in studies with negative symptoms as a secondary outcome. Similar results were found for studies focused on negative symptom reduction (Hedges’ g = 0.157, 95% CI −0.10 to 0.409, p = 0.225). Meta-regression revealed that stronger treatment effects were associated with earlier year of publication, lower study quality and with CBT provided individually (as compared with group-based).
The co-occurring beneficial effect of conventional CBT on negative symptoms found in older studies was not supported by more recent studies. It is now necessary to further disentangle effective treatment ingredients of older studies in order to guide the development of future CBT interventions aimed at negative symptom reduction.
Little is known about the effect of stimulant use (amphetamines, cocaine, ecstasy) on cognitive functioning in schizophrenia patients. The current study examined (1) whether recency and frequency of stimulant use is associated with cognitive functioning and (2) whether these associations differ between psychotic patients, their unaffected siblings and controls.
Participants completed a comprehensive cognitive test battery. Stimulant use was assessed by urinalysis and by the Composite International Diagnostic Interview (CIDI). Using random effects regression models, the main effects of Stimulant Use and the interaction with Diagnostic Status on cognitive functioning were assessed.
The interaction term between Stimulant Use and Diagnostic Status was not significant for any of the cognitive outcome variables, indicating similar effects of stimulant use in all three groups. Recent stimulant users showed more errors deficit in verbal learning in comparison to never users (Cohen's d = −0.60, p < 0.005). Lifetime frequent stimulant use was significantly associated with worse immediate and delayed verbal recall, working memory and acquired knowledge (Cohen's d = −0.22 to −0.29, p < 0.005). Lifetime infrequent stimulant use was not associated with significant cognitive alterations in comparison to never use.
The presence of cognitive deficits associated with lifetime stimulant use is dependent on the frequency of use, with no observed deficits in infrequent users and modest negative effects in frequent users.
Prevalence rates of malnutrition vary considerably internationally, partly due to differences in measurement methodology and instruments. In the present study, the same measurement methodology and instruments were used in The Netherlands, Germany and Austria. The aim of the present study was to investigate whether resident characteristics influence possible differences in malnutrition prevalence between countries. The study followed a cross-sectional, multi-centre design that measured malnutrition in nursing home residents from The Netherlands, Germany and Austria. Resident data were gathered using a standardised questionnaire. Malnutrition was operationalised using BMI, unintentional weight loss and nutritional intake. Data were analysed using an association model. The prevalence rates of malnutrition in The Netherlands, Germany and Austria were 18·3, 20·1 and 22·5 %, respectively. The multivariate generalised estimating equation (GEE) logistic regression analysis showed that sex, age, care dependency, the mean number of diseases and some specific diseases were influencing factors for whether the resident was malnourished or not. The OR of malnutrition in the three countries declined after including the influencing factors resulting from the multivariate GEE analysis. The present study reveals that differences in the prevalence rates of malnutrition in nursing homes in The Netherlands, Germany and Austria are influenced by different resident characteristics. Since other country-related factors could also play an important role in influencing differences in the prevalence rates of malnutrition between the countries (structural and process factors of malnutrition care policy). We recommend the investigation of these factors in future studies.
The association between depression after myocardial infarction and increased risk of mortality and cardiac morbidity may be due to cardiac disease severity.
To combine original data from studies on the association between post-infarction depression and prognosis into one database, and to investigate to what extent such depression predicts prognosis independently of disease severity.
An individual patient data meta-analysis of studies was conducted using multilevel, multivariable Cox regression analyses.
Sixteen studies participated, creating a database of 10 175 post-infarction cases. Hazard ratios for post-infarction depression were 1.32 (95% CI 1.26–1.38, P<0.001) for all-cause mortality and 1.19 (95% CI 1.14–1.24, P<0.001) for cardiovascular events. Hazard ratios adjusted for disease severity were attenuated by 28% and 25% respectively.
The association between depression following myocardial infarction and prognosis is attenuated after adjustment for cardiac disease severity. Still, depression remains independently associated with prognosis, with a 22% increased risk of all-cause mortality and a 13% increased risk of cardiovascular events per standard deviation in depression z-score.
Diet is well known to have beneficial health properties that extend beyond traditionally accepted nutritional effects. The approach involved in elucidating these beneficial physiological effects is becoming more important, as reflected by increasing research being undertaken. With growing consumer awareness of foods and food constituents and their relationship to health, the key questions for regulators, scientists and the food industry continue to relate to: (1) how consumers could be protected and have confidence that the health claims on foods are well supported by the evidence; (2) how research on physiological effects of food (constituents) and their health benefits could be stimulated and supported; (3) how research findings could be used in the development of innovative new food products. The objectives of this paper are to provide a set of recommendations on the substantiation of health claims for foods, to develop further guidance on the choice of validated markers (or marker patterns) and what effects are considered to be beneficial to the health of the general public (or specific target groups). Finally, the case for developing a standardised approach for assessing the totality of the available scientific data and weighing the evidence is proposed.
The relationship between cannabis use and cognitive functioning in patients with psychosis has yielded contradictory findings. In individuals at genetic high risk for psychosis, information is sparse. The aim of this study was to assess the association between recency and frequency of cannabis use and cognitive functioning in patients with psychosis and their unaffected siblings.
We conducted a cross-sectional study in 956 patients with non-affective psychosis, 953 unaffected siblings, and 554 control subjects. Participants completed a cognitive test battery including assessments of verbal learning, set shifting, sustained attention, processing speed, working memory, acquired knowledge, reasoning and problem solving and social cognition. Cannabis use was assessed by urinalysis and by the Composite International Diagnostic Interview. Using random-effect regression models the main effects of cannabis (recency and frequency) and the interaction with status (patient, sibling, control) on cognitive functioning were assessed.
Current cannabis use was associated with poorer performance on immediate verbal learning, processing speed and working memory (Cohen's d −0.20 to −0.33, p<0.005). Lifetime cannabis use was associated with better performance on acquired knowledge, facial affect recognition and face identity recognition (Cohen's d+0.17 to +0.33, p<0.005). There was no significant interaction between cannabis and status on cognitive functioning.
Lifetime cannabis-using individuals might constitute a subgroup with a higher cognitive potential. The residual effects of cannabis may impair short-term memory and processing speed.
Polarons and triplet excitons in conjugated polymers exhibit sub-gap absorptions which allow them to be identified spectroscopically. We have used quasi-steady-state induced absorption techniques on working polymer light-emitting diodes to study charge carriers and triplet excitons in devices. We identify absorptions due to charges, and at low temperatures can also resolve features due to triplet excitons. From the magnitude of the absorption features, we study the charge and triplet densities as a function of applied voltage. We obtain a value for the triplet generation rate at low temperatures and an estimate of the singlet exciton formation probability. Analysis of the triplet lifetime as a function of charge density reveals the presence of triplet-polaron interactions and we obtain a rate constant for this triplet annihilation process.
We have calculated J-V characteristics of an organic conducting sample (containing traps) including the Poole-Frenkel Effect (PFE). Both shallow and exponentially distributed traps are considered. We show that our approach is equivalent to combining the effect of trapping and using the field dependent mobility in one unified model. For shallow single level or shallow Gaussian traps, inclusion of PFE or using the (well-known) field dependent mobility gives the same dependence of current on voltage at a given temperature. However the value of zero field mobility µ0 comes out to be different. We have fabricated and measured the J-V curves of the ITO/MEH-OPV5/Al diodes. An extremely fast rise with voltage V is observed at small voltages, which can be interpreted either by the Schottky contact limited Shockley like current or by bulk space charge limited current with PFE. The correct mechanism can be determined by making J-V measurements at different temperatures.