Erratum: Hanbury Brown-Twiss Interferometry at a Free-Electron Laser [Phys. Rev. Lett. 111, 034802 (2013)].

This corrects the article DOI: 10.1103/PhysRevLett.111.034802.

Revealing Three-Dimensional Structure of an Individual Colloidal Crystal Grain by Coherent X-Ray Diffractive Imaging.

We present results of a coherent x-ray diffractive imaging experiment performed on a single colloidal crystal grain. The full three-dimensional (3D) reciprocal space map measured by an azimuthal rotational scan contained several orders of Bragg reflections together with the coherent interference signal between them. Applying the iterative phase retrieval approach, the 3D structure of the crystal grain was reconstructed and positions of individual colloidal particles were resolved. As a result, an exact stacking sequence of hexagonal close-packed layers including planar and linear defects were identified.

Hanbury Brown-Twiss interferometry at a free-electron laser.

We present measurements of second- and higher-order intensity correlation functions (so-called Hanbury Brown-Twiss experiment) performed at the free-electron laser (FEL) FLASH in the non-linear regime of its operation. We demonstrate the high transverse coherence properties of the FEL beam with a degree of transverse coherence of about 80% and degeneracy parameter of the order 10(9) that makes it similar to laser sources. Intensity correlation measurements in spatial and frequency domain gave an estimate of the FEL average pulse duration of 50 fs. Our measurements of the higher-order correlation functions indicate that FEL radiation obeys Gaussian statistics, which is characteristic to chaotic sources.

Single pulse coherence measurements in the water window at the free-electron laser FLASH.

The spatial coherence of free-electron laser radiation in the water window spectral range was studied, using the third harmonic (λ<(3rd) = 2.66 nm) of DESY's Free-electron LASer in Hamburg (FLASH). Coherent single pulse diffraction patterns of 1,2-Dioleoyl-sn-glycero-3-phosphocholine (DOPC) multilamellar lipid stacks have been recorded. The intensity histogram of the speckle pattern around the first lamellar Bragg peak, corresponding to the d = 5 nm periodicity of the stack, reveals an average number of transverse modes of M¯ = 3.0 of the 3rd harmonic. Using the lipid stack as a 'monochromator', pulse-to-pulse fluctuations in the third harmonic λ(3rd) have been determined to be 0.033 nm.

Effect evaluation of a self-management program for dutch workers with a chronic somatic disease: a randomized controlled trial.

PURPOSE: The objective of this study is to investigate the effect of a Self-Management Program for workers with a chronic disease. This program is based on the Chronic Disease Self-Management Program of Stanford University, modified for workers with a chronic somatic disease. METHODS: In a randomized controlled trial, the effectiveness of a Self-Management Program was evaluated. Participants were randomly assigned to the experimental group (n = 57) and the control group (n = 47). The experimental group received an intervention, the control group received care as usual. Primary outcome measures were self-efficacy at work and the attitude towards self-management at work. Secondary outcomes were the SF-12 health survey questionnaire, job satisfaction and intention to change job. The results were measured at baseline, after the intervention and 8 months after the intervention. RESULTS: The attitude towards self-management at work (enjoyment) improved after 8 months for the intervention group (p = 0.030). No other outcome variable differed significantly. As an interaction effect, it was found that low educated workers developed a better physical health quality (SF-12) in the intervention group compared with the control group. The attitude towards self-management at work (importance) improved in the intervention group for older and female workers and the attitude toward enjoying self-management at work improved for female workers only. CONCLUSION: The results show that low educated workers, older workers and women benefit significantly more from the training than higher educated workers, younger workers and men.

Spatial and temporal coherence properties of single free-electron laser pulses.

The experimental characterization of the spatial and temporal coherence properties of the free-electron laser in Hamburg (FLASH) at a wavelength of 8.0 nm is presented. Double pinhole diffraction patterns of single femtosecond pulses focused to a size of about 10×10 µm(2) were measured. A transverse coherence length of 6.2 ± 0.9 µm in the horizontal and 8.7 ± 1.0 µm in the vertical direction was determined from the most coherent pulses. Using a split and delay unit the coherence time of the pulses produced in the same operation conditions of FLASH was measured to be 1.75 ± 0.01 fs. From our experiment we estimated the degeneracy parameter of the FLASH beam to be on the order of 10(10) to 10(11), which exceeds the values of this parameter at any other source in the same energy range by many orders of magnitude.

Three-dimensional structure of a single colloidal crystal grain studied by coherent x-ray diffraction.

A coherent x-ray diffraction experiment was performed on an isolated colloidal crystal grain at the coherence beamline P10 at PETRA III. Using azimuthal rotation scans the three-dimensional (3D) scattered intensity from the sample in the far-field was measured. It includes several Bragg peaks as well as the coherent interference around these peaks. The analysis of the scattered intensity reveals the presence of plane defects in a single grain of the colloidal sample. We confirm these findings by model simulations. In these simulations we also analyze the experimental conditions required to phase the 3D diffraction pattern from a single colloidal grain. This approach has the potential to produce a high resolution image of the sample revealing its inner structure, with possible structural defects.

"My lung disease won't go away, it's there to stay": profiles of adaptation to functional limitations in workers with asthma and COPD.

PURPOSE: Earlier research has shown that adaptation (i.e., the way in which employees cope with limitations resulting from their disease) is associated with sick leave. Our aim was to investigate signs of adequate or inadequate adaptation in employees with asthma and COPD. METHODS: A Q-methodological study was carried out among 34 workers with asthma or COPD. RESULTS: Four adaptation profiles were distinguished: the eager, the adjusted, the cautious, and the worried workers. The adaptation profiles provide insight into the different ways in which workers with asthma and COPD cope with their illness at work. CONCLUSIONS: The adaptation profiles serve as a starting point for the design of appropriate (occupational) care. The eager workers experience little difficulties at work; the cautious workers may need assistance in learning how to accept their disease; the worried workers need reassurance, and may need reactivation; the adjusted workers deserve extra attention, and, when necessary, advice on how to live with their asthma or COPD.

Coherent-pulse 2D crystallography using a free-electron laser x-ray source.

Coherent diffractive imaging for the reconstruction of a two-dimensional (2D) finite crystal structure with a single pulse train of free-electron laser radiation at 7.97 nm wavelength is demonstrated. This measurement shows an advance on traditional coherent imaging techniques by applying it to a periodic structure. It is also significant that this approach paves the way for the imaging of the class of specimens which readily form 2D, but not three-dimensional crystals. We show that the structure is reconstructed to the detected resolution, given an adequate signal-to-noise ratio.

Fatigue, emotional exhaustion and perceived health complaints associated with work-related characteristics in employees with and without chronic diseases.

OBJECTIVES: Ageing of the Dutch working force and increasingly more stringent restrictions regarding early retirement and disability benefits are leading to higher numbers of workers with ill health. Until now, only a few studies have explored how employees with ill health perceive their work. This study investigated possible differences in scores on fatigue, emotional exhaustion, perceived health complaints and various work-related characteristics between chronically ill (CIWs) and non-chronically ill workers (NCIWs), as well as differences in associations between work- and health-related characteristics. METHODS: A questionnaire was sent to all employees of a Dutch university to collect data on perceived work-related and health-related characteristics (response 49.1%). Differences in various scores were analysed using chi (2)-tests and the general linear model. Associations between the work- and the health-related characteristics were determined by multiple linear regression analyses in the CIWs (n = 444) and NCIWs (n = 1,347) separately. Interaction terms were included to detect differences between the two groups. RESULTS: The results indicated that the CIWs had less favourable scores on the three health-related characteristics. Also, the CIWs scored less favourably than the NCIWs on almost all the work-related characteristics. In the two groups, negative work-related aspects, such as higher work pressure, contributed most to explaining the variance in the health-related characteristics. However, in the CIWs, fatigue was not explained by the work-related aspects as much as in the NCIWs. In the CIWs, the association between unpleasant treatment and the health-related characteristics was stronger than in the NCIWs, but there were indications that autonomy, possibilities for learning and social support from superiors also played an important role. CONCLUSIONS: CIWs perceived more fatigue, emotional exhaustion and health complaints than NCIWs. There were different patterns of associations between work- and health-related characteristics in the NCIWs and CIWs. Future studies on associations between work-related characteristics and health should take the presence of chronic disease into account.

Occupational health and general practice: from opportunities lost to opportunities capitalised?

BACKGROUND AND AIM: Western populations are in the middle of the epidemiological transition of chronic diseases. Care of patients with chronic disease is directed at optimising life expectancy and quality of life. Daily and social functioning, including paid work are part of the treatment objectives. Yet, advice for and support in work related coping with chronic diseases, and collaboration with occupational health are not--yet--part of routine curative medical care procedures. This is also the case in general practice, where most patients with chronic conditions are treated. This 'blind spot' signals a generic lost opportunity in optimizing the care of patients with chronic disease. This paper analyses from empirical data the importance of integrating work-related advice and support in general practice and explores potential evidence of the benefits this provides for patients: the opportunities that can be capitalised through better interaction between occupational physicians (OP) and general practitioners (GP). METHODS: The paper is based on a review of three sources: (i) Epidemiology of chronic diseases: the Nijmegen Continuous Morbidity Registration; (ii) The relevant guidelines of the Dutch College of General Practitioners; (iii) Studies of work-related implications of asthma and COPD management of GPs of the Nijmegen centre of Evidence-Based Practice. RESULTS: Chronic diseases like cardiovascular disease, diabetes mellitus, COPD and asthma dominate general practice and lead annually to a large number of consultations. Although a majority of patients are 65 years or older--in particular for the first three diseases--GPs also care for a substantial number of under-65 years old. General practice guidelines for these disorders advocate care directed at normal functioning but do not systematically address functioning in the working place. Analysis of work-related functioning in case of chronic respiratory diseases, however, highlight that work-related factors and circumstances play an important role in patients' coping strategies. Patients tend to ignore negative effects of their workplace on their physical condition and as a consequence suffer undue limitations. Despite these work related risks, COPD patients who were in paid employement perceived higher quality of life than COPD patients who were disabled for work, but had similar disease severity (airway obstruction). Interestingly, a programme of patients' self-management of asthma resulted, in comparison to GP-supervised usual care in a substantial and lasting reduction of asthma related absence from work and other social-daily activities. CONCLUSIONS AND DISCUSSION: All consultations with employees with a chronic (respiratory) disease can be considered as opportunities to supervise work-related implications of the disease. Patients value their ability to work but frequently apply inefficient coping through ignoring the implications of their circumstances for their disease. A more efficient coping can probably be achieved through a more active involvement of patients in managing their own disease. Guidelines--like the Dutch College of General Practitioners'--have developed into a sophisticated and generally respected system of guidance of patient care. Explicit emphasis of management in relation to the workplace may present a logical opportunity to capitalise on.

Health-related and work-related aspects associated with sick leave: a comparison of chronically ill and non-chronically ill workers.

OBJECTIVES: Our aims were to study to what extent chronically ill workers (CIWs) take more sick leave than non-chronically ill workers (NCIWs) and to explore which health-related and work-related aspects are associated with the sick leave patterns of the two groups. METHODS: A questionnaire on work, health and sick leave was sent to all employees of a university in The Netherlands (response: 49.1%). Analyses were conducted for 444 CIWs and 1,347 NCIWs. Odds ratios (ORs) were calculated to quantify the contribution of being chronically ill to sick leave in general, frequent sick leave, prolonged sick leave, and present sick leave. The contributions of health-related and work-related aspects to sick leave were investigated by multiple logistic regression analyses for both CIWs and NCIWs separately. RESULTS: CIWs showed significantly increased ORs for general, frequent, prolonged and present sick leave when compared with NCIWs. Fatigue, emotional exhaustion and perceived health complaints showed stronger associations with sick leave for both CIWs and NCIWs than various work-related aspects. Workers of 46 years of age and older showed less sick leave than workers under the age of 36. Male respondents and scientific personnel showed less frequent sick leave than the other respondents, and so did respondents working more than 40 h a week, compared with part-timers. The final regression models explained 8%-16% of the variance in sick leave. CONCLUSIONS: CIWs take two to three times more and longer sick leave than NCIWs. Health-related aspects are more strongly associated with sick leave than work-related aspects for both CIWs and NCIWs. Sick leave patterns were, nevertheless, only partly explained by health-related and work-related aspects. In any case, future studies of sick leave should certainly take the presence of chronic disease into account as an important determinant of sick leave.

[Illness due to work or to an overactive thyroid?]. / Ziek door het werk of een te hard werkende schildklier?

An incapacity to work brought about by stress was diagnosed in two women aged 40 and 38. They were both in conflict situations at work and had psychological problems. They stopped working but remained tired and irritable. After being unfit for work for more than a year they were diagnosed with hyperthyroidism which was treated appropriately. They both recovered and resumed work. Hyperthyroidism can impair physical and mental functioning. Presenting symptoms may be confusing, specifically if work-related factors appear to be the obvious implication. In The Netherlands, employees who become ill, consult their general practitioner or a medical specialist, who are concerned with diagnosis and treatment. They also report to their employer's occupational-health department, where the physician focuses on work-related factors that may impair health and on assessment of disability. Communication between all parties should be optimal.

Asthma and chronic obstructive pulmonary disease: differences between workers with and without sick leave.

OBJECTIVE: Determinants of sick leave should be investigated before interventions to reduce sick leave can be designed. This cross-sectional study compares employees with asthma and chronic obstructive pulmonary disease (COPD) with and without sick leave. METHODS: One hundred and eighteen participants with asthma and 71 with COPD underwent a lung function test [one-second forced expiratory volume (FEV1), forced vital capacity (FVC)] and completed questionnaires on health complaints, work characteristics, demographic and psychosocial variables, and self-reported sick leave in the past 12 months. Backward multivariate logistic regression analyses, with sick leave (no/any) as dependent variable, were conducted for asthma, COPD, and the total group. RESULTS: Lung function measures were not significantly associated with sick leave in any group (P > 0.05). For asthma, psychosocial variables (spending all energy at work, OR 0.7) and health complaints (frequency of dyspnoea, OR 0.4 and breathing problems such as coughing, wheezing, OR 1.1) were associated with sick leave. In the COPD group, age (OR 0.9) was the only significant variable to be maintained in the model. In the total group, work characteristics (adjustment in work pace, OR 3.3), age (OR 0.9) and spending all energy at work (OR 0.7) were maintained in the final model. CONCLUSION: Severity of the disease, as measured by lung function, is not a determinant of sick leave in asthma and COPD. Different processes play a role in asthma and COPD. Interventions for reducing sick leave should aim more at psychosocial factors than at treating the severity of the disease.

Work stress and health effects among university personnel.

OBJECTIVE: (1) To investigate the contribution of job characteristics and personal characteristics to the explanation of health effects among university personnel; (2) to investigate the differences between scientific personnel (SP) and non-scientific personnel (NSP); (3) to investigate whether health effects occurred one after another. METHODS: The well being at work of employees at a Dutch university (n=2,522) was investigated by means of a questionnaire. A model was constructed in which several job and personal characteristics were set out against health effects. The latter were assumed to occur in phases: decreased "job satisfaction" as an early effect, followed by increased "tension" and "emotional exhaustion", and possibly also by increased "perceived health complaints". The contribution of job and personal characteristics to the explanation of health effects was investigated by means of linear regression analysis, with separate analyses for SP and NSP. RESULTS: Positive job characteristics, especially professional expertise and work variety, contributed to the explanation of "job satisfaction". The major contributors to "tension" and "emotional exhaustion" were negative characteristics, such as work pressure. Besides the negative aspects, the major contributors to the explanation of "perceived health complaints" were sex, age and other health effects. In NSP, social support contributed to the explanation of "tension" and "emotional exhaustion", but not in SP. The explained variance of "job satisfaction" by the positive job characteristics in NSP was much higher than that in SP. To investigate whether health effects occurred one after another, we considered explained variance. Explained variance in "job satisfaction" was much higher than in "perceived health complaints". "Emotional exhaustion" and "tension" were in between. CONCLUSIONS: Contrary to expectations, decision latitude and social support played only minor roles. Also, the differences between SP and NSP were smaller than expected. As individual condition and burden of outside work also influence health effects, we recommend the inclusion of relevant personal factors in future studies.

Longitudinal changes in bronchial responsiveness associated with swine confinement dust exposure.

STUDY OBJECTIVES: Acute exposure to the air in swine confinement units causes bronchial hyperresponsiveness and inflammation of the airways. This study was performed to assess the longitudinal development of bronchial responsiveness in pig farmers and to establish exposure-response relationships. METHODS: A cohort of 171 pig farmers was followed over a 3-year period. Bronchial responsiveness was assessed by a histamine provocation test. Long-term average exposure to inhalable dust and endotoxin was determined by personal monitoring in summer and winter, using data on farm characteristics and activities. Time-weighted average (TWA) personal exposure to ammonia was measured. Data on farm characteristics were gathered in the same period. RESULTS: Mean increase in responsiveness was 2.52 doubling concentrations of histamine for a 10% decrease in FEV(1) and 1.36 doubling concentrations for a 20% decrease in FEV(1). Long-term average exposure to dust was 2.63 mg/m(3) and to endotoxin was 105 ng/m(3). TWA exposure to ammonia was 1.60 mg/m(3). After adjusting for age and smoking behavior, long-term average exposure to inhalable dust was associated with increases in bronchial responsiveness expressed as steps for provocative concentration causing 10% fall in FEV(1). TWA exposure to ammonia, use of wood shavings as bedding, and automated dry feeding were associated with increases in responsiveness expressed as steps for provocative concentration causing a 20% fall in FEV(1). CONCLUSIONS: Exposure to dust and ammonia in pig farms contributes to chronic inflammation of the airways and should be reduced.

Organic dust toxic syndrome in swine confinement farming.

BACKGROUND: Pig farmers are exposed to organic dust with pro-inflammatory capacities. This makes it likely that they suffer from organic dust toxic syndrome (ODTS). No studies that included unexposed control populations are available so far. METHODS: The prevalence of ODTS was established by the use of questionnaires in a group of 239 pig farmers and 311 rural controls working in nonagricultural occupations. RESULTS: Pig farmers suffered more often from ODTS than controls (6.4% vs. 2.6%, P < 0.05). Organic dust toxic syndrome was associated with symptoms of atopy (prevalence odds ratio (POR) 3.1, 95% confidence interval (CI) 1.2-8.0) and with the use of wood-shavings as bedding (POR 4.3, 95% CI 1.2-15.6). An inverse association with the number of years worked as pig farmer was found (up to 5 years vs. more than 5 years; POR 5.0, 95% CI 0.8-32.9). CONCLUSIONS: The prevalence of ODTS was elevated among pig farmers when compared to nonfarming, rural controls.

Health-based selection for asthma, but not for chronic bronchitis, in pig farmers: an evidence-based hypothesis.

In cross-sectional surveys among pig farmers an elevated prevalence of chronic bronchitis is usually reported, but not of asthma, despite many factors promoting the manifestation of asthma. To investigate this apparent contradiction a postal questionnaire survey was performed among 239 pig farmers and 311 rural controls. Pig farmers reported an elevated prevalence of symptoms of chronic bronchitis (20.2 versus 7.7%, p<0.001), but not of asthma (5.9 versus 5.5% for chest tightness). Among pig farmers the use of disinfectants (prevalence odds ratio (POR) 9.4, 95% confidence interval (CI) 1.6-57.2 for quaternary ammonium compounds) and aspects of the disinfecting procedure were associated with the prevalence of asthma symptoms. Compared with controls, pig farmers reported fewer allergies to common allergens (4.6 versus 14.6%, p<0.001 for pollen) and fewer symptoms of atopy in childhood (9.9 versus 17.2, p<0.05 for one or more of four symptoms). Atopy in childhood was strongly associated with the prevalence of asthma symptoms (POR 4.1, 95% CI 2.2-7.7), but not with chronic bronchitis. Health-based selection of nonasthmatics for pig farming, which tends to mask a work-related hazard for asthma, is offered as an explanation for these results.

A LISREL analysis of work-related risk factors and health complaints in the nursing profession.

OBJECTIVES: To fit a model which describes the complex interaction between various work-related factors and both musculoskeletal and psychosomatic complaints of nurses simultaneously and to compare the results with those of two LISREL models, in which the health outcome variables are analyzed separately in terms of their correlation with the same set of work-related factors. MATERIALS AND METHODS: Nurses (n=718) working in four Dutch nursing homes completed a questionnaire about work-related factors and musculoskeletal and psychosomatic complaints (response 81%). LISREL was used to describe and analyse the models. RESULTS: The full model had a reasonable overall fit. The strongest (and statistically significant) correlations were found between work postures and musculoskeletal complaints and between psychosocial work demands and psychosomatic complaints. In the two single models, health outcomes showed statistically significant correlations with the same work-related factors as they did in the full model. The full model could be slightly improved when the variable somatized complaints (e.g., dizzyness, headache) was related both to musculoskeletal complaints and to psychosomatic complaints. CONCLUSIONS: Although a model that simultaneously describes more dependent variables appears to provide a better approximation of the complexity of the actual relationship between work-related factors and health effects, the models in which only one health outcome is studied seem to give a proper description of the data at hand. This is an important finding because these single health outcome models resemble the usual analysis strategy by means of standard regression analysis. The adapted version of the full model suggests that musculoskeletal complaints of nurses can partly be understood as non-specific health complaints.