Large fluctuations in locational marginal prices.

This paper investigates large fluctuations of locational marginal prices (LMPs) in wholesale energy markets caused by volatile renewable generation profiles. Specifically, we study events of the form [Formula: see text] where LMP is the vector of LMPs at the n power grid nodes, and α-, [Formula: see text] are vectors of price thresholds specifying undesirable price occurrences. By exploiting the structure of the supply-demand matching mechanism in power grids, we look at LMPs as deterministic piecewise affine, possibly discontinuous functions of the stochastic input process, modelling uncontrollable renewable generation. We use techniques from large deviations theory to identify the most likely ways for extreme price spikes to happen, and to rank the nodes of the power grid in terms of their likelihood of experiencing a price spike. Our results are derived in the case of Gaussian fluctuations, and are validated numerically on the IEEE 14-bus test case. This article is part of the theme issue 'The mathematics of energy systems'.

2020 ESC Guidelines on acute coronary syndrome without ST-segment elevation : Recommendations and critical appraisal from the Dutch ACS and Interventional Cardiology working groups.

Recently, the European Society of Cardiology (ESC) has updated its guidelines for the management of patients with acute coronary syndrome (ACS) without ST-segment elevation. The current consensus document of the Dutch ACS working group and the Working Group of Interventional Cardiology of the Netherlands Society of Cardiology aims to put the 2020 ESC Guidelines into the Dutch perspective and to provide practical recommendations for Dutch cardiologists, focusing on antiplatelet therapy, risk assessment and criteria for invasive strategy.

Indications for an early invasive strategy in NSTE-ACS patients.

An early invasive strategy in patients who have acute coronary syndrome without ST-elevation (NSTE-ACS) can improve clinical outcome in high-risk subgroups. According to the current guidelines of the European Society of Cardiology (ESC), the majority of NSTE-ACS patients are classified as "high-risk". We propose to prioritise patients with a global registry of acute coronary events (GRACE) risk score >140 over patients with isolated troponin rise or electrocardiographic changes and a GRACE risk score <140. We also acknowledge that same-day transfer for all patients at a high risk is not necessary in the Netherlands since the majority of Dutch cardiology departments are equipped with a catheterisation laboratory where diagnostic coronary angiography is routinely performed in NSTE-ACS patients. Therefore, same-day transfer should be restricted to true high-risk patients (in addition to those NSTE-ACS patients with very high-risk (VHR) criteria) in centres without coronary angiography capabilities.

Short-term career perspectives of young cardiologists in the Netherlands.

BACKGROUND: Since it was anticipated that the need for doctors would increase due to demographic changes, the number of positions for medical specialty training programs has increased from the year 2000 onwards. However, the number of permanent positions for young cardiologists did not follow that trend leading to concerns about future employment. Therefore, the aim of the current study was to assess short-term career perspectives of young cardiologists in the Netherlands. METHODS: All cardiologists who ended their training between 1 January 2011 and 31 December 2014 were invited to fill in a questionnaire about their first employment status and were followed yearly until the participant had a permanent position. The timespan between the end of training and the moment of permanent employment was assessed. Furthermore, the association between professional profile and short-term career perspectives was investigated. RESULTS: The observed unemployment was 1.6% and lasted less than a year in all cases. Of the participants, 77% started their career with a temporary contract; within four years this was 7%. Of young cardiologists, 46% started their career as a fellow and 24% as an attending physician. A total of 29% of male cardiologists started their career with a permanent contract as compared with 12% of females (p = 0.01). Within two years this difference was no longer observed. CONCLUSIONS: Unemployment is low among young cardiologists. Most cardiologists start their career with a temporary contract. The time to a permanent contract is slightly longer for female cardiologists as compared with males.

Optimal duration of dual antiplatelet therapy after percutaneous coronary intervention or after acute coronary syndrome : Practical lessons from a review.

To prevent recurrent ischaemic events, dual antiplatelet therapy (DAPT) is the standard of care after percutaneous coronary intervention and in the treatment of acute coronary syndrome. Recent evidence supports an adjusted DAPT duration in selected patients.The current paper aims to encourage cardiologists to actively search for patients benefiting from either shorter or prolonged duration DAPT and proposes an algorithm to identify patients who are likely to benefit from such an alternative strategy.Individualised DAPT duration should be considered in high-risk anatomic and/or clinical subgroups or in patients at increased haemorrhagic risk with low ischaemic risk. Both thrombotic and haemorrhagic risk should be assessed in all patients. In patients undergoing percutaneous coronary intervention, the interventional cardiologist could advise on the minimal duration of DAPT. However, in contrast to the minimum duration of DAPT for stent thrombosis prevention, longer duration DAPT is aimed at prevention of spontaneous myocardial infarction, and not at stent thrombosis, and thus the key to success is to treat the patient's overall thrombotic risk.The advice on the duration of DAPT must be documented in the patient's records and communicated with the treating physician and general practitioner. DAPT duration should be reassessed at least on a yearly basis.

The effects of work-related and individual factors on the Work Ability Index: a systematic review.

This paper systematically reviews the scientific literature on the effects of individual and work-related factors on the Work Ability Index (WAI). Studies on work ability published from 1985 to 2006 were identified through a structured search in PubMed, and Web of Science. Studies were included if the WAI was used as measure of work ability and if quantitative information was presented on determinants of work ability. In total, 20 studies were included with 14 cross-sectional studies and six longitudinal studies. Factors associated with poor work ability, as defined by WAI, were lack of leisure-time vigorous physical activity, poor musculoskeletal capacity, older age, obesity, high mental work demands, lack of autonomy, poor physical work environment, and high physical work load. The WAI is associated with individual characteristics, lifestyle, demands at work, and physical condition. This multifactorial nature of work ability should be taken into account in health promotion programmes aimed at maintaining and promoting the participation of the labour force and improvement of the performance at work.

A new method for tracking and analyzing illness and morbidity among active duty U.S. Air Force aviators.

The United States Air Force (USAF) presents a unique opportunity to investigate disease incidence, duration, and severity, through analysis of flyer medical records. This article describes the creation and analysis of a 15,275-record database of flyer-physician interactions, recorded over several years from 18 U.S. Air Force Bases. A descriptive analysis presents the leading causes of outpatient morbidity as measured by total days disqualified for flying duties (downtime). Upper respiratory infection (URI)/cold/congestion was the leading cause of illness, representing 4,485/15,700 visits with a median downtime of 6 d, and with 90% of the flyers allowed back into the cockpit within 15 d. A diagnosis coding system was developed specifically for this project that differs from the standard International Classification of Disease-Revision 9 (ICD-9 CM) (1) nomenclature. The rationale for such an approach is discussed.

Occupational classification according to work demands: an evaluation study.

The use of job title as crude exposure measure in epidemiological studies is often inevitable when the available exposure data is scarce. In this study, an existing classification scheme of all job titles in the Netherlands into six categories of physical and mental work demands, constructed by expert judgement, was evaluated. Furthermore, a revision of this classification scheme for a research project on the relation between age, physical work demands, and musculoskeletal complaints was proposed and evaluated as well. For the evaluation, self-reported work demands, derived from questionnaire data of 38,921 employees and quantified by a scale of physical work demands and mental work demands, were used. Based on comparison of the mean scale scores of the several categories of work demands at group level, both classification schemes showed construct validity. Notwithstanding several limitations, the use of the presented classification schemes in epidemiological studies seems particularly challenging and rewarding when analysing data at group level from large and heterogeneous occupational populations. These kind of exploratory studies may generate new hypothesis on the basic patterns concerning work-related disorders, and can also be informative from a policy making perspective.

[Eleven-Cities skating marathon and the windchill factor]. / Elfstedentocht en gevoelstemperatuur; 'windchill'-factor.

The weather conditions during the 15th Eleven Cities ice skating marathon (200 kilometers) in Friesland (the Netherlands) on 4 January, 1997, were better than predicted. For measurement of the windchill factor the Steadman scale is preferred to the Siple and Passel scale. For ice skaters the windchill factor is lower than for the spectators, due to the drag effect.

Peritoneal dialysis-associated peritonitis of zoonotic origin, when minor gets major.

A 62-year-old patient with peritoneal dialysis (PD)-associated peritonitis is described. Identical strains of Pasteurella multocida and Streptococcus minor were cultured from the dialysate, and from the saliva of her recently adopted stray cat. Pasteurella is not often encountered as pathogen in PD-associated peritonitis, Streptococcus minor has never been cultured in human infection before. We emphasise the importance of hygiene in peritoneal dialysis and the need for testing pets when zoonotic pathogens are cultured.

The value of clinical examination in diagnosing pelvic fractures in blunt trauma patients: a brief review.

PURPOSE OF THE STUDY: To evaluate the value of a pelvic X-ray compared to clinical examination in diagnosing pelvic ring fractures, using computed tomography (CT) as the gold standard, in alert [Glasgow Coma Scale (GCS) ≥ 13] adult blunt trauma patients in the emergency room. METHODS: A systematic literature search was performed in PubMed and Embase. The results were screened on their titles and abstracts using in- and exclusion criteria. Subsequently, the selected articles were critically appraised for their relevance and validity. RESULTS: Two studies investigating the diagnostic value of clinical examination and pelvic X-ray compared to CT were identified. Both studies demonstrate higher negative predictive values for clinical examination [0.99 (95% confidence interval [CI] 0.98-1.0) and 1.0 (95% CI 0.99-1.0)] compared to the negative predictive values of pelvic X-ray [0.98 (95% CI 0.93-0.99) and 0.99 (95% CI 0.99-1.0)]. The positive predictive values for clinical examination were low [0.18 (95% CI 0.16-0.23) and 0.35 (95% CI 0.30-0.42)] compared to pelvic X-ray [0.97 (95% CI 0.96-0.98) and 0.97 (95% CI 0.90-0.99)]. CONCLUSIONS: In alert blunt trauma patients, pelvic X-ray only has additional diagnostic value for the detection of pelvic ring fractures if the clinical examination is positive. Pelvic X-ray should not be performed if the clinical examination is negative. In this manner, the expenditure of time, costs, and radiation are optimized.

Acute and subacute stent thrombosis after primary percutaneous coronary intervention for ST-segment elevation myocardial infarction: incidence, predictors and clinical outcome.

BACKGROUND: Early coronary stent thrombosis occurs most frequent after primary percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI). OBJECTIVES: To identify the specific predictors of, respectively, acute and subacute stent thrombosis in patients after primary PCI for STEMI. PATIENTS/METHODS: Consecutive STEMI patients with angiographically confirmed early stent thrombosis were enrolled and compared in a 2 : 1 ratio with a matched control group. Clinical outcome was collected up to 1 year. RESULTS: Of 5842 STEMI patients treated with primary PCI, 201 (3.5%) presented with a definite early stent thrombosis. Of these, 97 (1.7%) had acute stent thromboses and 104 (1.8%) had subacute stent thromboses. Postprocedurally discovered dissection, undersizing and smaller stent diameter were the strongest predictors for acute stent thrombosis. No glycoprotein IIb/IIIa therapy and the use of drug-eluting stents were also associated with acute stent thrombosis. Lack of clopidogrel therapy in the first 30 days after the index PCI was the strongest predictor for subacute stent thrombosis. Mortality rates at 1-year follow-up were lower for acute stent thrombosis than for subacute stent thrombosis (8.3% vs. 13.2%, P = 0.294). The incidence of definite recurrent stent thrombosis at 1-year follow up was significantly lower after a first definite acute stent thrombosis than after a first definite subacute stent thrombosis (6.4% vs. 19.3%, P = 0.007 at 1 year). CONCLUSIONS: The specific risk factors for, respectively, acute and subacute stent thrombosis after primary PCI vary greatly. Mortality rates are high for both categories of stent thrombosis. However, recurrent stent thrombosis occurs more frequently after subacute stent thrombosis.

Diminished human immunodeficiency virus type 1 reverse transcription and nuclear transport in primary macrophages arrested in early G(1) phase of the cell cycle.

Previously, we and others have demonstrated that the process of reverse transcription of human immunodeficiency virus type 1 (HIV-1) is disturbed in nondividing macrophages and quiescent T lymphocytes. Here we analyzed which phase of the cell cycle in macrophages is crucial for early steps in the HIV-1 replication cycle. HIV-1 Ba-L-inoculated macrophages arrested early in the G(1) phase by n-butyrate contained incomplete products of reverse transcription. In gamma-irradiated macrophages, reverse transcription was successfully completed but proviral integration could not be detected. In these cells, nuclear import was disturbed as reflected by the absence of two-long-terminal-repeat circles. In macrophages arrested late in G(1) phase by aphidicolin or 5, 6-dichloro-1-beta-D-ribofuranosyl-benzimidazole (DRB), reverse transcription was unaffected. Proviral integration occurred efficiently in DRB-treated macrophages, whereas integrated proviral DNA could not be detected after aphidicolin treatment. Arrest at G(2) phase of the cell cycle by nocodazole did not affect reverse transcription or proviral integration. Treatment of macrophages with hydroxyurea (HU), which reduces the intracellular deoxynucleoside triphosphate (dNTP) pool by blocking the de novo synthesis of dNTP, resulted in a dose-dependent inhibition of HIV-1 reverse transcription. This could partially be restored by the addition of nucleoside precursors. Addition of nucleoside precursors enhanced both reverse transcription and cell proliferation. However, the disturbed reverse transcription observed in the nonproliferating and n-butyrate-treated macrophages could not be restored by addition of nucleoside precursors. Similar to observations in quiescent T lymphocytes, incomplete proviral DNA species were arrested in the cytoplasm of the macrophages. Our results indicate that also in primary macrophages the intracellular nucleotide pools and other cellular factors that coincide with late G(1) phase of the cell cycle may contribute to efficient reverse transcription and nuclear localization.

Gender differences in upper extremity musculoskeletal complaints in the working population.

OBJECTIVES: This study analysed the association between gender and upper extremity musculoskeletal complaints, among the general working population and in various occupational groups. The hypothesis was tested whether the higher risk for women in the general working population for these complaints could partly be explained by differences in the distribution of men and women in occupations with different risks for the onset of upper extremity musculoskeletal complaints. METHODS: The data for this study came from cross-sectional questionnaire data from 16,874 employees categorised in 21 different occupational classes. Associations between gender and complaints of the upper extremities were analysed for the total study sample and for each occupational class separately. An adjustment was made for the variable 'occupational class' in the final model in order to study the impact of occupational gender segregation on gender differences in upper extremity complaints in the working population. RESULTS: In the total study sample, significantly higher risks of complaints of the neck, shoulder, elbow, and wrist among the women were observed. Within many occupational classes, women reported significantly higher risks than did men, in particular for complaints of the neck and shoulder. Adjustment for occupational class showed increased risks for female workers for complaints of the neck, shoulder, elbow, and wrist, hence, rejecting our hypothesis on occupational gender segregation as an explanation for the higher risks for upper extremity complaints among women in the general working population. CONCLUSIONS: This study confirmed the presence of gender differences in upper extremity musculoskeletal complaints among the working population and in many occupational classes, with female workers having the higher risk. The results, however, do not lend support to a differential occupational exposure theory as an explanation for the higher risks for these complaints among women in the general working population. Careful consideration of gender influence in ergonomic epidemiological studies is recommended.

Physical workload and the aging worker: a review of the literature.

In the coming decades, demographic, economic and social changes will result in an increased proportion of elderly persons in the workforce in most industrialized countries. This trend is causing growing interest in the problems of the aging worker in current employment. The objective of this particular paper is to provide more insight into the impact of aging on the balance between physical work capacity and physical workload. To this end, the scientific literature in the field is reviewed and ordered by means of a specific conceptual model of "aging and physical workload". A progressive decline in physical work capacity, characterized by diminished aerobic capacity and muscular capacity, has consistently been reported. However, inter-individual differences appear to be considerable. The question of whether there are systematic differences in physical work demands between younger and older workers within occupations has been answered vaguely. Conflicting results in this matter bring into discussion the role of the actual working method as one of the determinants of the physical workload. An age-related imbalance between physical workload and physical work capacity is suggested to result in a chronic overload, increasing the risk of long-term health effects such as musculoskeletal complaints and disorders. For many aging workers in physically demanding occupations, extreme physical workloads, increasing the risk of disease or disablement, are still reported. The multiconceptual study of aging and physical workload in the present paper reveals several possibilities for preventive measures. However, as information is still lacking, additional research is needed, in particular on the onset and development of long-term effects on health in relation to age and work demands.

Senior workers in the Dutch construction industry: a search for age-related work and health issues.

An increase in morbidity and disability rates in the Dutch construction industry is expected due to work force aging. In order to reduce these rates, an occupational health services instrument for senior construction workers will be developed to gather information on present problems in work and health, expectations for the future, and potential preventive policy measures. The aim of this study was to identify age-related work and health issues among construction workers that could be included in the new instrument. Questionnaire data on work and health from 1881 young (16-30 years) and 1946 old (45-64 years) construction workers were analyzed and a literature search was performed. Results show that health problems, in particular for musculoskeletal disorders, increase with advancing age, demonstrating the need for occupational health arrangements for the maintenance and improvement of work ability of senior construction workers.

Test-retest reliability of the Work Ability Index questionnaire.

The goal of the study was to assess the test-retest reliability of the Work Ability Index (WAI) questionnaire. Reliability was tested using a test-retest design with a 4 week interval between measurements. Valid data were collected among 97 elderly construction workers aged 40 years and older. We analysed the test-retest reliability of the WAI score itself (range 7-49 points) and classification in one of the four WAI categories based on this score: poor (7-27 points); moderate (28-36 points); good (37-43 points); and excellent work ability (44-49 points). Exactly the same WAI score on both measurements was reported by 25% of the subjects and 95% of the individual differences between measurements were found to be <6.86 points (two times standard deviation). Despite the individual changes between measurements, no significant difference was reported in the mean WAI score at group level between test and retest measurements (40.4 versus 39.9). The percentage of observed agreement for the classification of subjects in one of the four WAI categories on both measurements equalled 66%. The results of this study provided evidence of an acceptable test-retest reliability of the classification of subject's work ability by means of the WAI questionnaire. At group level, the mean WAI score and classification into WAI categories were found to be a stable measure over a 4 week interval. These results give additional support for the applicability of the questionnaire in occupational health research and the daily practice of occupational health care.

After-effects of night work on physical performance capacity and sleep quality in relation to age.

The after-effects of night work on physical performance capacity and sleep quality were studied. Ten younger (age < or = 34 years) and eight older (age > 34 years) experienced shift workers were examined. Subjects performed cycle ergometer tests at an exercise intensity requiring 70% of the individual maximal oxygen uptake. Two conditions were studied: a baseline condition, i.e. the last day of a 4 days-off period, and a recovery condition after a period of seven consecutive night shifts, i.e. the second day-off after the night-shift period (32 h after leaving the night-shift period). Sleep quality of the sleep period preceding the test was also measured for both conditions. During the recovery condition the endurance time (i.e. time to exhaustion) was reduced by an average of 20% (-160s, P < 0.05) for the older shift workers only. In both age groups exercise ventilation, heart rate, oxygen uptake, perceived exertion and sleep quality remained unaffected. These findings support the hypothesis that the aging shift worker is faced with increasing complaints, even after the night-shift period. However, to clarify the mechanisms responsible for these after-effects of night work, further extensive studies must be designed.

CPT-11 in human colon-cancer cell lines and xenografts: characterization of cellular sensitivity determinants.

CPT-11, a new semisynthetic derivative of camptothecin, is active in a number of tumor types in the clinic, including colon cancer. CPT-11 is a drug that is converted into the active metabolite SN-38 by a carboxylesterase. Experiments were performed to obtain more insight in the cellular characteristics in 5 unselected human colon-cancer cell lines that account for the differential sensitivity to CPT-11 and SN-38. In vitro, the sensitivity to CPT-11 and SN-38 was highest in LS174T and COLO 320 cells, intermediate in SW1398 cells and lowest in COLO 205 and WiDr cells. SN-38 was 130 to 570 times more active than CPT-11. CPT-11 induced complete remissions in 6 out of 12 COLO 320 tumors grown as subcutaneous xenografts, but was not effective in WiDr tumors. The cellular carboxylesterase activity did not relate to the sensitivity to CPT-11. The enzyme activity was higher in normal mouse tissues, i.e., serum and liver, than in COLO 320 or WiDr xenografts, indicating that tumor carboxylesterase is of minor importance for CPT-11 efficacy. The topoisomerase-1 mRNA expression in tumor cells was not predictive of the antiproliferative effects of CPT-11 or SN-38. We observed a positive relationship between the DNA topoisomerase-1 activity and the cellular sensitivity to carboxylesterase-activated CPT-11 (r = 0.75, p < 0.1) as well as to SN-38 (r = 0.89, p < 0.05). The higher topoisomerase-1 activity in COLO 320 cells and tumors when compared with that in WiDr cells and tumors reflected the differences in sensitivity to the drug(s). In conclusion, the DNA topoisomerase-1 activity was the best determinant for CPT-11/SN-38 sensitivity in this panel of unselected human colon-cancer cell lines.