Integrability of a conducting elastic rod in a magnetic field

We consider the equilibrium equations for a conducting elastic rod placed in a uniform magnetic field, motivated by the problem of electrodynamic space tethers. When expressed in body coordinates the equations are found to sit in a hierarchy of non-canonical Hamiltonian systems involving an increasing number of vector fields. These systems, which include the classical Euler and Kirchhoff rods, are shown to be completely integrable in the case of a transversely isotropic rod; they are in fact generated by a Lax pair. For the magnetic rod this gives a physical interpretation to a previously proposed abstract nine-dimensional integrable system. We use the conserved quantities to reduce the equations to a four-dimensional canonical Hamiltonian system, allowing the geometry of the phase space to be investigated through Poincar\'e sections. In the special case where the force in the rod is aligned with the magnetic field the system turns out to be superintegrable, meaning that the phase space breaks down completely into periodic orbits, corresponding to straight twisted rods.Comment: 19 pages, 1 figur

Detection of the tulip breaking virus (TBV) in tulips using optical sensors

The tulip breaking virus (TBV) causes severe economic losses for countries that export tulips such as the Netherlands. Infected plants have to be removed from the field as soon as possible. There is an urgent need for a rapid and objective method of screening. In this study, four proximal optical sensing techniques for the detection of TBV in tulip plants were evaluated and compared with a visual assessment by crop experts as well as with an ELISA (enzyme immunoassay) analysis of the same plants. The optical sensor techniques used were an RGB color camera, a spectrophotometer measuring from 350 to 2500 nm, a spectral imaging camera covering a spectral range from 400 to 900 nm and a chlorophyll fluorescence imaging system that measures the photosynthetic activity. Linear discriminant classification was used to compare the results of these optical techniques and the visual assessment with the ELISA score. The spectral imaging system was the best optical technique and its error was only slightly larger than the visual assessment error. The experimental results appear to be promising, and they have led to further research to develop an autonomous robot for the detection and removal of diseased tulip plants in the open field. The application of this robot system will reduce the amount of insecticides and the considerable pressure on labor for selecting diseased plants by the crop expert. © 2010 The Author(s

Mycobacterium bovis prevalence affects the performance of a commercial serological assay for bovine tuberculosis in African buffaloes

The endemic presence of bovine tuberculosis (BTB) in African buffaloes in South Africa has severe consequences for BTB control in domestic cattle, buffalo ranching and wildlife conservation, and poses a potential risk to public health. This study determined the BTB prevalence in free-ranging buffaloes in two game reserves and assessed the influence of the prevalence of mycobacterial infections on the performance of a commercial cattle-specific serological assay for BTB (TB ELISA). Buffaloes (n = 997) were tested with the tuberculin skin test and TB ELISA; a subset (n = 119) was tested longitudinally. Culture, PCR and sequencing were used to confirm infection with M. bovis and/or non-tuberculous mycobacteria (NTM). Prevalence of BTB, but not NTM, influenced the TB ELISA performance. Multiple testing did not increase test confidence. The findings strongly illustrate the need for development of novel assays that can supplement existing assays for a more comprehensive testing scheme for BTB in African buffaloes

Associations between empathy, inhibitory control, and physical aggression in toddlerhood

Impaired empathy has been associated with aggression in children, adolescents and adults, but results have been contradictory for the preschool period. Impaired inhibitory control also increases the risk of aggression, and possibly moderates empathy‐aggression associations. The current study investigated whether empathy and inhibitory control are associated with aggression in toddlerhood. Furthermore, we aimed to clarify the role of inhibitory control in empathy and aggression, specifically, whether inhibitory control moderates the association between empathy and aggression. During a laboratory visit at age 30 months (N = 103), maternal reports of physical aggression were obtained and child inhibitory control was examined using a gift delay task. Empathy was examined by obtaining behavioral observations and recording physiological responses (heart rate response and respiratory sinus arrhythmia response) to an empathy‐eliciting event (i.e., simulated distress). Reduced inhibitory control was associated with more aggression. Behavioral and physiological indicators of empathy were not associated with aggression. Hierarchical regression analyses revealed an interaction effect of heart rate response to distress simulation with inhibitory control in the prediction of aggression. Post hoc analyses indicated a negative association between heart rate response and aggression when inhibitory control was high, but a positive association was found in toddlers who demonstrated low inhibitory control. These results suggest that children are less aggressive when they have both high levels of empathy and inhibitory control. Therefore, both empathy and inhibition are important targets for interventions aiming to reduce or prevent aggression at a young age

Repeated Cross-Sectional Randomized Response Data Taking Design Change and Self-Protective Responses into Account

Abstract. Randomized response (RR) is an interview technique that can be used to protect the privacy of respondents if sensitive questions are posed. This paper explains how to measure change in time if a binary RR question is posed at several time points. In cross-sectional research settings, new insights often gradually emerge. In our setting, a switch to another RR procedure necessitates the development of a trend model that estimates the effect of the covariate time if the dependent variable is measured by different RR designs. We also demonstrate that it is possible to deal with self-protective responses, thus accommodating our trend model with the latest developments in RR data analysis. Keywords: linear trend, longitudinal data, misclassification, randomized response, repeated cross-sections, self-protective responses Randomized response (RR) is an interview technique that can be used if sensitive questions are posed and respondents are reluctant to answer directly In addition to the RR setting, misclassification probabilities occur in several other fields of research. The one most closely related to RR is the postrandomization method (PRAM, Kooiman, Willenborg, & Gouweleeuw, 1997) that misclassifies values of categorical variables using a computerized process after the data are collected to protect the respondents' privacy. PRAM uses RR after the data collection. Misclassification also plays a role in medicine and epidemiology with the probabilities correctly classified as a case (sensitivity) or noncase (specificity), see This paper proposes a model to measure changes in time whenever RR is used to pose sensitive questions at several time points cross-sectionally. The model is illustrated with data from a Dutch repeated cross-sectional study on noncompliance to rules regarding social benefits. Data are collected every 2 years since 2000 and given that measures to prevent regulatory noncompliance are intensified during this period, the question arises as to whether the prevalence of regulatory noncompliance changes over the years and how the change can be modeled. Considering time a covariate, we propose a method to measure the effect of this covariate if the dependent variable is measured by RR. Several aspects of the cross-sectional study at hand make it impossible to use standard analysis methods and necessitate a new approach in the analysis of RR data to deal with research questions of this type. Firstly, the fact that RR variables represent misclassified responses on categorical variables precludes the use of, for example, the linear logit model (Agresti, 2002, p. 180), to test for a linear trend. Using the framework o

Circulating angiopoietin-2 levels in the course of septic shock: relation with fluid balance, pulmonary dysfunction and mortality

Contains fulltext : 79899.pdf (publisher's version ) (Closed access)PURPOSE: To investigate whether angiopoietin-2, von Willebrand factor (VWF) and angiopoietin-1 relate to surrogate indicators of vascular permeability, pulmonary dysfunction and intensive care unit (ICU) mortality throughout the course of septic shock. METHODS: In 50 consecutive mechanically ventilated septic shock patients, plasma angiopoietin-2, VWF and angiopoietin-1 levels and fluid balance, partial pressure of oxygen/inspiratory oxygen fraction and the oxygenation index as indicators of vascular permeability and pulmonary dysfunction, respectively, were measured until day 28. RESULTS: Angiopoietin-2 positively related to the fluid balance and pulmonary dysfunction, was higher in non-survivors than in survivors and independently predicted non-survival throughout the course of septic shock. VWF inversely related to the fluid balance and pulmonary dysfunction throughout the course of septic shock, was comparable between survivors and non-survivors and predicted non-survival on day 0 only. Angiopoietin-1 positively related to pulmonary dysfunction throughout the course, but did not differ between survivors and non-survivors. CONCLUSIONS: In contrast to VWF, plasma angiopoietin-2 positively relates to fluid balance, pulmonary dysfunction and mortality throughout the course of septic shock, in line with a suggested mediator role of the protein

Non-destructive Assessment of Quality and Yield for Grass-Breeding

Selection of cultivars has, until now, been based mainly on dry matter (DM) yields because of the high costs of sampling and chemical analysis. Imaging spectroscopy could reduce costs by limiting sampling and harvesting of individual plots to reference samples (Schut et al., accepted). In this study, the prediction accuracy of DM yields and chemical composition with imaging spectroscopy is evaluated for cultivar selection purposes

Diagnostic value of a heart-type fatty acid-binding protein (H-FABP) bedside test in suspected acute coronary syndrome in primary care

AbstractBackgroundTo determine the diagnostic accuracy of a rapid heart-type fatty acid-binding protein (H-FABP) test in patients suspected of acute coronary syndrome (ACS) in primary care.MethodsGeneral practitioners included 298 patients suspected of ACS. In all patients, whether referred to hospital or not, ECG and cardiac biomarker testing was performed. ACS was determined in accordance with international guidelines. Multivariate analysis was used to determine the value of H-FABP in addition to clinical findings.ResultsMean patient age was 66years (SD 14), 52% was female and 66 patients (22%) were diagnosed with ACS. The H-FABP bedside test was performed within 24h (median 3.1, IQR 1.5 to 7.1) after symptom onset. The positive predictive value (PPV) of H-FABP was 65% (95% confidence interval (CI) 50–78). The negative predictive value (NPV) was 85% (95% CI 80–88). Sensitivity was 39% (29–51%) and specificity 94% (90–96%). Within 6h after symptom onset, the PPV was 72% (55–84) and the NPV was 83% (77–88), sensitivity 43% (31–57%) and specificity 94% (89–97%). Adding the H-FABP test to a diagnostic model for ACS led to an increase in the area under the receiver operating curve from 0.66 (95% CI 0.58–0.73) to 0.75 (95% CI 0.68–0.82).ConclusionThe H-FABP rapid test provides modest additional diagnostic certainty in primary care. It cannot be used to safely exclude rule out ACS. The test can only be used safely in patients otherwise NOT referred to hospital by the GP, as an extra precaution not to miss ACS (‘rule in’)

Pelvic Floor Rehabilitation After Rectal Cancer Surgery A Multicenter Randomized Clinical Trial (FORCE Trial)

Objective: To investigate the effects of PFR after LAR compared to usual care without PFR. Summary of background data: Functional complaints, including fecal incontinence, often occur after LAR for rectal cancer. Controversy exists about the effectiveness of PFR in improving such postoperative functional outcomes. Methods: This was a multicenter, randomized controlled trial involving 17 Dutch centers. Patients after LAR for rectal cancer were randomly assigned (1:1) to usual care or PFR and stratified by sex and administration of neoadjuvant therapy. Selection was not based on severity of complaints at baseline. Baseline measurements were taken 3 months after surgery without temporary stoma construction or 6 weeks after stoma closure. The primary outcome measure was the change in Wexner incontinence scores 3 months after randomization. Secondary outcomes were fecal incontinence-related quality of life, colorectal-specific quality of life, and the LARS scores. Results: Between October 2017 and March 2020, 128 patients were enrolled and 106 randomly assigned (PFR n = 51, control n = 55); 95 patients (PFR n = 44, control n = 51) were assessable for final analysis. PFR did not lead to larger changes in Wexner incontinence scores in nonselected patients after LAR compared to usual care [PFR: -2.3, 95% confidence interval (CI) -3.3 to -1.4, control: - 1.3, 95% CI - 2.2 to - 0.4, P = 0.13]. However, PFR was associated with less urgency at follow-up (odds ratio 0.22, 95% CI 0.06-0.86). Patients without near-complete incontinence reported larger Wexner score improvements after PFR (PFR: -2.1, 95% CI -3.1 to - 1.1, control: -0.7, 95% CI -1.6 to 0.2, P = 0.045). For patients with at least moderate incontinence PFR resulted in relevant improvements in all fecal incontinence-related quality of life domains, while the control group deteriorated. These improvements were even larger when patients with near-complete incontinence were excluded. No serious adverse PFR-related events occurred. Conclusion: No benefit was found of PFR in all patients but several subgroups were identified that did benefit from PFR, such as patients with urgency or with at least moderate incontinence and no near-complete incontinence. A selective referral policy (65%-85% of all patients) is suggested to improve postoperative functional outcomes for patients after LAR for rectal cancer