De speurneus van een sluipwesp

Sluipwespen zijn de bekendste biologische bestrijders. Met gewone wespen hebben deze diertjes niets te maken. Het zijn kleine, tengere insecten die heel goed zijn in het opsporen van hun slachtoffers. Die slachtoffers - of beter gezegd, gastheren waar zij hun eitjes in kunnen leggen - zijn meestal de goed gecamoufleerde eitjes of rupsen van vlinders. Eigenlijk is het een wonder dat de sluipwespen die slachtoffers zo goed weten te vinden op de oneindige akkers. Bij het zoeken naar eitjes en rupsen maken sluipwespen vooral gebruik van hun reukvermogen. De planten waarvan ze eten produceren een kenmerkende geur die alleen wordt afgegeven als er insecten van de plant eten. De geuren die een plant produceert bij insectenvraat zijn vaak specifiek voor de soort of zelfs de leeftijd van de rups die op de plant zit. Een sluipwesp kan dus van een afstand ruiken welke gastheer er op een plant te vinden i

Disaster and associated changes in physical and mental health in older residents

BACKGROUND: Long-term health consequences of disasters have not been studied extensively, one reason amongst others is that no pre-disaster observation is available. This study focuses on an aeroplane crash on an Amsterdam suburb. The ongoing Longitudinal Aging Study Amsterdam has one pre-disaster and several post-disaster observations, making it possible to study changes in health, taking pre-disaster health characteristics into account. METHODS: Three exposure groups are distinguished: those living within a radius of 1 km from the disaster (initial n=39), those living between a radius of 1 and 2 km from the disaster (initial n=56), and those living in the rest of the city of Amsterdam (initial n=508). Health measures include general health, health in comparison with age peers, functional limitations, disability and cognitive functioning. These measures are based on self-ratings, interviewer observations, or both. RESULTS: Older persons living closest to the disaster area are likely to experience health decline in the wake of a disaster, over and above the health decline that would occur normally with aging. The disaster-associated health decline is small, and most obvious in the ability to perform actions (such as mobility), but is not observed in either disability in daily functioning, nor in self-perceptions of health. Cognitive functioning even shows a short-term improvement. CONCLUSION: These findings suggest substantial resilience in older adults, despite their common health problem

Lumbar supports and education for the prevention of low back pain in industry - A randomized controlled trial

CONTEXT Low back pain is a frequent and costly health problem. Prevention of low back pain is important both for the individual patient and from an economic perspective. OBJECTIVE To assess the efficacy of lumbar supports and education in the prevention of low back pain in industry. DESIGN A randomized controlled trial with a factorial design. SETTING The cargo department of an airline company in the Netherlands. PARTICIPANTS A total of 312 workers were randomized, of whom 282 were available for the 6-month follow-up. INTERVENTIONS Subjects were randomly assigned to 4 groups: (1) education (lifting instructions) and lumbar support, (2) education, (3) lumbar support, and (4) no intervention. Education consisted of 3 group sessions on lifting techniques with a total duration of 5 hours. Lumbar supports were recommended to be used during working hours for 6 months. MAIN OUTCOME MEASURES Low back pain incidence and sick leave because of back pain during the 6-month intervention period. RESULTS Compliance with wearing the lumbar support at least half the time was 43%. In the 282 subjects for whom data were available, no statistically significant differences in back pain incidence (48 [36%] of 134 with lumbar support vs 51 [34%] of 148 without, P=.81) or in sick leave because of low back pain (mean, 0.4 days per month with lumbar support vs 0.4 days without, P=.52) were found among the intervention groups. In a subgroup of subjects with low back pain at baseline, lumbar supports reduced the number of days with low back pain per month (median, 1.2 vs 6.5 days per month; P=.03). CONCLUSIONS Overall, lumbar supports or education did not lead to a reduction in low back pain incidence or sick leave. The results of the subgroup analysis need to be confirmed by future research. Based on our results, the use of education or lumbar supports cannot be recommended in the prevention of low back pain in industry

Ein neues Verfahren für namensbasierte Zufallsstichproben von Migranten

The set of best methods for sampling mi- grant populations includes name-based sampling. So far this is done using either ad-hoc lists or onomastic dictionaries for the classi cation of names. This paper pro- poses a new name-based procedure, which uses a Bayes-classi er for the n-grams of the name. The new procedure is fault-tol- erant of alternate spellings, and also allows the classi cation of names that are not found in dictionaries. It was tested using the names of about 1.600 foreigners in the PASS panel. Finally, a CATI survey based on the new method in Hesse is described

Подавление синхронной помехи в ЯКР с модуляцией Зеемана

Рассмотрены принципы частотной модуляции и модуляции Зеемана в ядерном квадрупольном резонансе и показаны преимущества последней. Предложен метод устранения синхронной помехи, вызываемой переключением магнитного поля. Приведены результаты наблюдения резонансной линии ¹⁴N с достоверной формой в образце гексаметилентетрамине массой 2 г.Розглянуто принципи частотної модуляції та модуляції Зеемана в ядерному квадрупольному резонансі та показано переваги останньої. Запропоновано метод усунення синхронної завади, спричиненої перемиканням магнітного поля. Наведено результат спостереження резонансної лінії ¹⁴N з достовірною формою у зразку гексаметилентетраміну масою 2 г.The principles of frequency and Zeeman modulation in nuclear quadrupole resonance were considered, and the advantages of the latter were shown. The authors propose a method to eliminate the synchronous noise caused by switching of the magnetic field. Results of observations of the resonance line with ¹⁴N in the hexamethylenetetramine sample weighing 2 g were given

Measuring sick leave: a comparison of self-reported data on sick leave and data from company records

The objective of this study was to compare sick leave data obtained from questionnaires with data from company records. During a period of 12 months, questionnaires were completed monthly for 6 months and then at 9 and 12 months. The sensitivity and specificity of questionnaires for detecting an episode of sick leave were determined, using the company records as a reference standard. In addition, the duration of sick leave episodes reported in the two data sets was compared. In this analysis, company records were not assumed to be superior, and agreement was assessed with intraclass correlation coefficients (ICCs). The sensitivity of questionnaires for detecting an episode of sick leave was 55% (95% CI = 0.50-0.60) and the specificity 83% (95% CI = 0.72-0.94). The ICC for all episodes was 0.58 (95% CI = 0.47-0.67). The only satisfactory ICC (0.87; 95% CI = 0.74-0.93) was found for the questionnaires at 9 and 12 months. No large systematic differences were found between the duration of episodes reported in the two data sets. In conclusion, in our study, the sensitivity of questionnaires for detecting an episode of sick leave was very low. Furthermore, when episodes were recalled, there was little agreement on the duration of the episode between questionnaire data and data in the company records. Based on these results and considering the risk of missing questionnaires, data on sick leave gathered from company records are clearly preferable as an outcome measure in research