210 results on '"Bart, H."'
Search Results
2. The Rouché Theorem for Fredholm functions: An enhanced version.
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Bart, H., Ehrhardt, T., and Silbermann, B.
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OPERATOR functions , *FREDHOLM operators - Abstract
The classical Rouché Theorem from complex function theory has been generalized to a result involving Fredholm operator valued functions (see [9] and [6]). The setting in question is (generally) a non-commutative one, so actually there are two versions of the generalization. In this paper, a unifying enhanced variant is presented involving the notion of the spectral radius. Its proof is based on a maximum principle for the spectral radius. An example is given showing that the enhanced Rouché Theorem presented here is a genuine improvement over the earlier version of the result. [ABSTRACT FROM AUTHOR]
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- 2024
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3. Influence of different data-averaging methods on mean values of selected variables derived from preoperative cardiopulmonary exercise testing in patients scheduled for colorectal surgery.
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Franssen, Ruud F. W., Sanders, Bart H. E., Takken, Tim, Vogelaar, F. Jeroen, Janssen-Heijnen, Maryska L. G., and Bongers, Bart C.
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ANAEROBIC threshold , *EXERCISE tests , *PREHABILITATION , *PROCTOLOGY , *CARBON dioxide , *CARDIOPULMONARY fitness - Abstract
Introduction: Patients with a low cardiorespiratory fitness (CRF) undergoing colorectal cancer surgery have a high risk for postoperative complications. Cardiopulmonary exercise testing (CPET) to assess CRF is the gold standard for preoperative risk assessment. To aid interpretation of raw breath-by-breath data, different methods of data-averaging can be applied. This study aimed to investigate the influence of different data-averaging intervals on CPET variables used for preoperative risk assessment, as well as to evaluate whether different data-averaging intervals influence preoperative risk assessment. Methods: A total of 21 preoperative CPETs were interpreted by two exercise physiologists using stationary time-based data-averaging intervals of 10, 20, and 30 seconds and rolling average intervals of 3 and 7 breaths. Mean values of CPET variables between different data averaging intervals were compared using repeated measures ANOVA. The variables of interest were oxygen uptake at peak exercise (VO2peak), oxygen uptake at the ventilatory anaerobic threshold (VO2VAT), oxygen uptake efficiency slope (OUES), the ventilatory equivalent for carbon dioxide at the ventilatory anaerobic threshold (VE/VCO2VAT), and the slope of the relationship between the minute ventilation and carbon dioxide production (VE/VCO2-slope). Results: Between data-averaging intervals, no statistically significant differences were found in the mean values of CPET variables except for the ventilatory equivalent for carbon dioxide at the ventilatory anaerobic threshold (P = 0.001). No statistically significant differences were found in the proportion of patients classified as high or low risk regardless of the used data-averaging interval. Conclusion: There appears to be no significant or clinically relevant influence of the evaluated data-averaging intervals on the mean values of CPET outcomes used for preoperative risk assessment. Clinicians may choose a data-averaging interval that is appropriate for optimal interpretation and data visualization of the preoperative CPET. Nevertheless, caution should be taken as the chosen data-averaging interval might lead to substantial within-patient variation for individual patients. Clinical trial registration: Prospectively registered at ClinicalTrials.gov (NCT05353127). [ABSTRACT FROM AUTHOR]
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- 2023
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4. Digital Transgender Archive.
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Everts, Bart H.
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DIGITAL libraries , *TRANSGENDER communities - Abstract
The article reviews the web site Digital Transgender Archive, located at https://www.digitaltransgenderarchive.net/.
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- 2024
5. Rank decomposition under zero pattern constraints and [formula omitted]-free directed graphs.
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Bart, H., Ehrhardt, T., and Silbermann, B.
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DIRECTED graphs , *VECTOR spaces , *INTEGER programming , *GRAPH algorithms , *MATRICES (Mathematics) - Abstract
For a block upper triangular matrix, a necessary and sufficient condition has been given to let it be the sum of block upper rectangular matrices satisfying certain rank constraints; see [12]. The proof involves elements from Integer Programming (totally unimodular systems of equations playing a role in particular) and employs Farkas' Lemma. The linear space of block upper triangular matrices can be viewed as being determined by a special pattern of zeros. The present paper is concerned with the question whether the decomposition result can be extended to situations where other, less restrictive, zero patterns play a role. It is shown that such generalizations do indeed hold for certain directed graphs determining the pattern of zeros. The graphs in question are what will be called L -free. This notion is akin to other graph theoretical concepts available in the literature, among them the one of being N -free in the sense of [16]. [ABSTRACT FROM AUTHOR]
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- 2021
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6. Understanding right ventricular dyssynchrony: Its myriad determinants and clinical relevance.
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Fraser, Alan G., Bijnens, Bart H., and Friedberg, Mark K.
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TETRALOGY of Fallot , *MAGNETIC resonance imaging , *RIGHT ventricular hypertrophy , *SCIENTIFIC literature , *AEROBIC capacity - Abstract
In this issue of I Experimental Physiology i , Ewalts et al. (2021) report that the degree of RV intraventricular dyssynchrony is related to an interaction between RV preload (volume) and afterload (PA pressure). Keywords: dyssynchrony; loading; right ventricle EN dyssynchrony loading right ventricle 797 800 4 04/02/21 20210401 NES 210401 It is a well-worn cliché that the right ventricle (RV) is forgotten or neglected, yet it is already the subject of a huge scientific literature. The RV preload was estimated using the echocardiographic surrogate marker of end-diastolic area on an apical four-chamber image, meaning that changes in RV shape and global volumes and function were not explicitly measured. It is clear that pulmonary arterial (PA) pressure and RV function are major predictors of morbidity and mortality in many cardiovascular diseases, but improving RV function as a therapeutic target remains elusive. [Extracted from the article]
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- 2021
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7. Personality traits and academic performance: Correcting self-assessed traits with vignettes.
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Coenen, Johan, Golsteyn, Bart H. H., Stolp, Tom, and Tempelaar, Dirk
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PERSONALITY , *VIGNETTES , *EMOTIONAL stability , *CONSCIENTIOUSNESS , *HIGHER education - Abstract
In this study, we investigate whether Conscientiousness, Emotional Stability and Risk Preference relate to student performance in higher education. We employ anchoring vignettes to correct for heterogeneous scale use in these non-cognitive skills. Our data are gathered among first-year students at a Dutch university. The results show that Conscientiousness is positively related to student performance, but the estimates are strongly biased upward if we use the uncorrected variables. We do not find significant relationships for Emotional Stability but find that the point estimates are larger when using the uncorrected variables. Measured Risk Preference is negatively related to student performance, yet this is fully explained by heterogeneous scale use. These results indicate the importance of using more objective measurements of personality traits. [ABSTRACT FROM AUTHOR]
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- 2021
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8. Deceased by default: Consent systems and organ-patient mortality.
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Golsteyn, Bart H. H. and Verhagen, Annelore M. C.
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TRANSPLANTATION of organs, tissues, etc. , *ORGAN donation , *MORTALITY - Abstract
Previous research shows that countries with opt-out consent systems for organ donation conduct significantly more deceased-donor organ transplantations than those with opt-in systems. This paper investigates whether the higher transplantation rates in opt-out systems translate into equally lower death rates among organ patients registered on a waiting list (i.e., organ-patient mortality rates). We show that the difference between consent systems regarding kidney- and liver-patient mortality rates is significantly smaller than the difference in deceased-donor transplantation rates. This is likely due to different incentives between the consent systems. We find empirical evidence that opt-out systems reduce incentives for living donations, which explains our findings for kidneys. The results imply that focusing on deceased-donor transplantation rates alone paints an incomplete picture of opt-out systems' benefits, and that there are important differences between organs in this respect. [ABSTRACT FROM AUTHOR]
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- 2021
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9. Increase the yield of bioactive compounds from elder bark and annatto seeds using ultrasound and microwave assisted extraction technologies.
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Bachtler, S. and Bart, H.-J.
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EXTRACTION techniques , *BIOACTIVE compounds , *MICROWAVE heating , *ULTRASONIC imaging , *URSOLIC acid , *OLDER people - Abstract
We describe techniques to rapidly increase the yield of bioactive compounds from plant sources such as elder bark and annatto seeds using microwave dielectric heating and ultrasonic cavitation bubbles, a substantial improvement over conventional heating methods. For elder bark, the optimal extraction parameters were obtained with ethanol, using 0.01 L g−1 of solvent to material and extracting for at least an hour at 55 °C. Ursolic acid was found to be more abundant in barks. Under the optimal conditions, the yields of oleanolic acid and ursolic acid were about 86% while using ultrasound assisted extraction and about 92% while using microwaves, respectively. Using the optimal extraction parameters for annatto seeds: ethyl acetate, the ratio of solvent to material at 0.05 L g−1 and at least 30 min. extraction time, the yield of bixin reached about 85% with sonication and 95% with microwave heating. Assisted extraction techniques, with microwave assisted extraction being the most optimal technique, enhanced the extraction efficiencies and extracted higher concentrations when compared to standard methods. [ABSTRACT FROM AUTHOR]
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- 2021
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10. Are estimates of intergenerational mobility biased by non-response? Evidence from the Netherlands.
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Golsteyn, Bart H. H. and Hirsch, Stefa
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INTERGENERATIONAL mobility , *SURVEYS , *LANGUAGE exams , *INTERGENERATIONAL relations , *A priori - Abstract
Intergenerational mobility is often studied using survey data. In such settings, selective unit or item non-response may bias estimates. Linking Dutch survey data to administrative income data allows us to examine whether selective responses bias the estimated relationship between parental income and children's mathematics and language test scores in grades 6 and 9. We find that the estimates of these relationships are biased downward due to parental unit non-response, while they are biased upwards due to item non-response. In the analyses of both unit and item non-response, the point estimates for language and mathematics test scores point in the same direction but only one of the two relationships is significant. These findings suggest that estimates of intergenerational mobility based on survey data need to be interpreted with caution because they may be biased by selective non-response. The direction of such bias is difficult to predict a priori. Bias due to unit and item non-response may work in opposing directions and may differ across outcomes. [ABSTRACT FROM AUTHOR]
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- 2019
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11. Sustained effects of prior red light on pupil diameter and vigilance during subsequent darkness.
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Van Der Meijden, Wisse P., Te Lindert, Bart H. W., Ramautar, Jennifer R., Wei, Yishul, Coppens, Joris E., Kamermans, Maarten, Cajochen, Christian, Bourgin, Patrice, and Van Someren, Eus J. W.
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PUPIL (Eye) , *PHYSIOLOGICAL effects of light , *SLEEP physiology , *WAVELENGTHS , *VIGILANCE (Psychology) , *NONFICTION , *PHYSIOLOGY - Abstract
Environmental light can exert potent effects on physiology and behaviour, including pupil size, vigilance and sleep. Previous work showed that these non-image forming effects can last long beyond discontinuation of shortwavelength light exposure. The possible functional effects after switching off long-wavelength light, however, have been insufficiently characterized. In a series of controlled experiments in healthy adult volunteers, we evaluated the effects of five minutes of intense red light on physiology and performance during subsequent darkness. As compared to prior darkness, prior red light induced a subsequent sustained pupil dilation. Prior red light also increased subsequent heart rate and heart rate variability when subjects were asked to perform a sustained vigilance task during the dark exposure. While these changes suggest an increase in the mental effort required for the task, it could not prevent a post-red slowing of response speed. The suggestion that exposure to intense red light affects vigilance during subsequent darkness, was confirmed in a controlled polysomnographic study that indeed showed a post-red facilitation of sleep onset. Our findings suggest the possibility of using red light as a nightcap. [ABSTRACT FROM AUTHOR]
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- 2018
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12. Petronarratology: A Bioregional Approach to Oil Stories.
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Welling, Bart H.
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ECOCRITICISM , *NARRATOLOGY , *FOSSIL fuels & the environment , *POWER resources & the environment - Abstract
In "Petronarratology: A Bioregional Approach to Oil Stories", Bart Welling argues that ecocritics and narratologists have an important role to play in challenging the narratives that help perpetuate the modern world's catastrophic addiction to fossil fuels. Welling builds on the concept of reinhabitation, a central idea in the grassroots bioregional movement, as he explores strategies through which authors have reinhabited (i.e., transformed from within) not just oil-polluted places but problematic energy narratives, such as narratives that euphemize hydrocarbons as "energy" in the first place. Focusing on books by David Gessner and Stephanie LeMenager, Welling identifies six features of reinhabitory petronarratives: (1) they acknowledge their authors' personal debts to oil; (2) they own up to the enmeshment of environmentally oriented ways of thinking in our hydrocarbon-fuelled culture; (3) they make room for the voices of ordinary residents of this culture, including people whose political perspectives clash with those of the authors; (4) they take seriously the reinhabitory capacities of nonhuman beings; (5) they rethink petroleum itself as a new kind of character in the fictions of "petromodernity"; and (6) they describe physical encounters with unprocessed hydrocarbons, thus addressing the massive problems posed by fossil fuels on a productively non-apocalyptic scale. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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13. Solvent extraction in columns in a droplet breakage domain.
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Korb, C. and Bart, H.-J.
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METAL analysis , *SOLVENT extraction , *SURFACE active agents , *ION exchange (Chemistry) , *COALESCENCE (Chemistry) , *PHOSPHORIC acid - Abstract
Extraction of metals in columns is scarce despite the advantage of low solvent inventory and the feasibility of high throughputs. Fast extraction kinetics allow short residence times and thus small apparatus height. A simulation of column concentration profiles via droplet population balances is less sophisticated as with surface active ion exchangers droplet breakage dominates and coalescence is hindered (rigid droplet surface). The extraction of Zn with D2EHPA (di(2-ethylhexyl)phosphoric acid) in a countercurrent Kühni column was investigated and the impact of different breakage kernels analyzed. Experiments in a lab scale test cell based on a DN32 Kühni extraction column geometry gave the basis to validate existing correlations and kernels for droplet breakage probability and daughter droplet size distribution. Since single droplet breakage tests were performed, a breakage dominated regime prevailed in the investigations. This yielded into a new unified correlation for the latter valid for different column geometries and physical and reactive extraction systems. As to this, a more firm basis for the simulation and design of stirred columns in hydrometallurgical application is established. [ABSTRACT FROM AUTHOR]
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- 2017
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14. Investigation of piperazine benzamides as human β3 adrenergic receptor agonists for the treatment of overactive bladder.
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Harper, Bart H., Wang, Liping, Zhu, Cheng, Kar, Nam F., Li, Bing, Moyes, Christopher R., Goble, Stephen D., Costa, Melissa, Dingley, Karen, Di Salvo, Jerry, Ha, Sookhee N., Hurley, Amanda, Li, Xiaofang, Miller, Randy R., Nagabukuro, Hiroshi, Salituro, Gino M., Smith, Sean, Struthers, Mary, Hale, Jeffrey J., and Edmondson, Scott D.
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PIPERAZINE , *BENZAMIDE , *BETA adrenoceptors , *ADRENERGIC receptors , *OVERACTIVE bladder , *THERAPEUTICS - Abstract
The synthesis of a novel class of piperazine benzamide (reverse amides) targeting the human β 3 -adrenergic receptor for the treatment of overactive bladder (OAB) is described. The SAR studies directed towards maintaining well established β 3 potency and selectivities while improving the overall pharmacokinetic profile in the reverse amide class will be evaluated. The results and consequences associated with functional activity at the norepinephrine transporter (NET) will also be discussed. [ABSTRACT FROM AUTHOR]
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- 2017
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15. What grades and achievement tests measure.
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Golsteyn, Bart H. H., Borghans, Lex, Humphries, John Eric, and Heckman, James J.
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COGNITIVE testing , *PERSONALITY & society , *LIFE , *ACHIEVEMENT tests , *INTELLIGENCE levels ,SOCIAL aspects - Abstract
Intelligence quotient (IQ), grades, and scores on achievement tests are widely used as measures of cognition, but the correlations among them are far from perfect. This paper uses a variety of datasets to show that personality and IQ predict grades and scores on achievement tests. Personality is relatively more important in predicting grades than scores on achievement tests. IQ is relatively more important in predicting scores on achievement tests. Personality is generally more predictive than IQ on a variety of important life outcomes. Both grades and achievement tests are substantially better predictors of important life outcomes than IQ. The reason is that both capture personality traits that have independent predictive power beyond that of IQ. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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16. The magnetic cataclysmic variable LSQ1725-64.
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Fuchs, J. T., Dunlap, Bart H., Dennihy, E., O'Donoghue, D., Clemens, J. C., Reichart, D. E., Moore, J. P., LaCluyze, A. P., Haislip, J. B., and Ivarsen, K. V.
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CATACLYSMIC variable stars , *ASTRONOMICAL photometry , *ASTRONOMICAL spectroscopy , *ECLIPSING binaries , *WHITE dwarf stars , *ZEEMAN effect - Abstract
We present new photometry and spectroscopy of the 94 m eclipsing binary LSQ1725-64 that provide insight into the fundamental parameters and evolutionary state of this system. We confirm that LSQ1725-64 is a magnetic cataclysmic variable whose white dwarf has a surface-averaged magnetic field strength of 12.5 ± 0.5 MG measured from Zeeman splitting. The spectral type and colour of the secondary, as well as the eclipse length, are consistent with other secondaries that have not yet evolved through the period minimum expected for cataclysmic variables. We observe two different states of mass transfer and measure the transition between the two to occur over about 45 orbital cycles. In the low state, we observe photometric variations that we hypothesize to arise predominantly from two previously heated magnetic poles of the white dwarf. Our precise eclipse measurements allow us to determine binary parameters of LSQ1725-64 and we find it contains a high-mass (0.966 ± 0.027 M⊙) white dwarf if we assume a typical mass-radius relationship for a CO core white dwarf. We also measure an eclipse of the accretion stream after the white dwarf eclipse, and use it to estimate an upper limit of the mass transfer rate. This derived limit is consistent with that expected from angular momentum loss via gravitational radiation alone. [ABSTRACT FROM AUTHOR]
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- 2016
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17. Time discounting and criminal behavior.
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Åkerlund, David, Golsteyn, Bart H. H., Grönqvist, Hans, and Lindahl, Lena
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CRIMINAL behavior , *LEGAL evidence , *CRIME , *INTELLECT , *TIME - Abstract
One of the most basic predictions of almost any model of crime is that individual time preferences matter. However, empirical evidence on this fundamental property is essentially nonexistent. To our knowledge, this paper provides the first pieces of evidence on the link between time discounting and crime. We use a unique dataset that combines a survey-based measure of time discount rates (at age 13) with detailed longitudinal register data on criminal behavior spanning over 18 y. Our results show that individuals with short time horizons have a significantly higher risk of criminal involvement later in life. The magnitude of the relationship is substantial and corresponds to roughly one-third of the association between intelligence and crime. [ABSTRACT FROM AUTHOR]
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- 2016
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18. Does Expert Advice Improve Educational Choice?
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Borghans, Lex, Golsteyn, Bart H. H., and Stenberg, Anders
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COUNSELORS , *SELF-evaluation , *ROBUST statistics , *EDUCATIONAL counseling , *EDUCATION research - Abstract
This paper reports evidence that an individual meeting with a study counselor at high school significantly improves the quality of choice of tertiary educational field, as self-assessed 18 months after graduation from college. To address endogeneity, we explore the variation in study counseling practices between schools as an instrumental variable (IV). Following careful scrutiny of the validity of the IV, our results indicate a significant and positive influence of study counseling on the quality of educational choice, foremost among males and those with low educated parents. The overall result is stable across a number of robustness checks. [ABSTRACT FROM AUTHOR]
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- 2015
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19. CFD-Simulation von Blasenströmungen mittels Euler-Lagrange-Ansatz und stochastischer Modellierung.
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Weber, A. and Bart, H.-J.
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- 2015
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20. School Quality and the Development of Cognitive Skills between Age Four and Six.
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Borghans, Lex, Golsteyn, Bart H. H., and Zölitz, Ulf
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COGNITIVE development , *COGNITIVE ability , *COGNITION in children , *TEST scoring , *ACHIEVEMENT tests , *SCHOOL choice - Abstract
This paper studies the extent to which young children develop their cognitive ability in high and low quality schools. We use a representative panel data set containing cognitive test scores of 4-6 year olds in Dutch schools. School quality is measured by the school’s average achievement test score at age 12. Our results indicate that children in high-quality schools develop their skills substantially faster than those in low-quality schools. The results remain robust to the inclusion of initial ability, parental background, and neighborhood controls. Moreover, using proximity to higher-achieving schools as an instrument for school choice corroborates the results. The robustness of the results points toward a causal interpretation, although it is not possible to erase all doubt about unobserved confounding factors. [ABSTRACT FROM AUTHOR]
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- 2015
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21. The benefit of a geriatric nurse practitioner in a multidisciplinary diagnostic service for people with cognitive disorders.
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Ament, Bart H. L., Wolfs, Claire A. G., Kempen, Gertrudis I. J. M., Ambergen, Ton, Verhey, Frans R. J., and De Vugt, Marjolein E.
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COGNITION disorders research , *GERIATRICS , *MENTAL health , *DEMENTIA , *NEUROBEHAVIORAL disorders - Abstract
Background: The aim of the study was to evaluate whether adding a geriatric nurse practitioner (GNP) to an out-patient diagnostic multidisciplinary facility for patients with cognitive disorders (Diagnostic Observation Center for PsychoGeriatry, DOC-PG) could improve quality of care. DOC-PG combines hospital diagnostics and care assessment from a community mental health team and provides the general practitioner (GP) with advice for treatment and management. In a previous study, we found that 28.7% of the advice made by this service was not followed up on by the GP. Methods: Two cohorts were studied: a group of patients with added GNP (n = 114) and a historical reference sample (n = 137). Both groups followed the same diagnostic protocol and care approach, but, in the GNP group, a care coordinator was added in order to communicate the advice from the DOC-PG to the GP. The primary outcome was the concordance rate of GPs regarding the advice. At the patient level, health-related quality of life (HRQoL) was assessed. Self-Rated Burden and care-related quality of life were measured at the informal caregiver level. Measures were conducted immediately after DOC-PG diagnosis and after 6 and 12 months. Univariate analyses, logistic regression analyses, and mixed model multilevel analyses were used to test differences between both groups. Results: Total concordance rates were significantly higher in the GNP group compared to the reference sample (82.1 and 71.3%, respectively; p < 0.001). No improvement in patient HRQoL was identified. Among the informal caregivers, a significant reduction of Self-Rated Burden was found in the GNP group at 12 months (adjusted mean difference -1.724, 95% CI -2.582 to -0.866; p < 0.001). Conclusions: Adding a GNP to an outpatient diagnostic multidisciplinary facility for patients with cognitive disorders may improve the GP concordance rate of the advice from the DOC-PG and reduce subjective burden of the informal caregiver. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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22. Adomian decomposition method solution of population balance equations for aggregation, nucleation, growth and breakup processes.
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Hasseine, A. and Bart, H.-J.
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DECOMPOSITION method , *NUCLEATION , *NONLINEAR systems , *PARTICLE size distribution , *DENSITY functionals - Abstract
The dynamic behavior of particulate processes under the influence of the nonlinear aggregation term, nucleation, growth and breakup is studied. Analytic solutions are obtained from the integro-differential population balance equation governing the particle size distribution density function for special cases by the Adomian decomposition method (ADM) and are compared with other analytical solutions available in the literature. It avoids the difficulty numerical stability that often characterizes general numerical techniques in this area. It generates an infinite series which converges uniformly to the exact solution of the problem. For the case where there are no previous results a comparison between the present method and projection method which include collocation techniques is made. The results obtained indicate that the Adomian decomposition method is highly accurate, efficient and are useful for further work. [ABSTRACT FROM AUTHOR]
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- 2015
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23. Assessment of Wall Elasticity Variations on Intraluminal Haemodynamics in Descending Aortic Dissections Using a Lumped-Parameter Model.
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Rudenick, Paula A., Bijnens, Bart H., Segers, Patrick, García-Dorado, David, and Evangelista, Arturo
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ELASTICITY (Physiology) , *AORTIC dissection , *MORTALITY , *PARAMETERS (Statistics) , *HEMODYNAMICS , *HEALTH outcome assessment - Abstract
Descending aortic dissection (DAD) is associated with high morbidity and mortality rates. Aortic wall stiffness is a variable often altered in DAD patients and potentially involved in long-term outcome. However, its relevance is still mostly unknown. To gain more detailed knowledge of how wall elasticity (compliance) might influence intraluminal haemodynamics in DAD, a lumped-parameter model was developed based on experimental data from a pulsatile hydraulic circuit and validated for 8 clinical scenarios. Next, the variations of intraluminal pressures and flows were assessed as a function of wall elasticity. In comparison with the most rigid-wall case, an increase in elasticity to physiological values was associated with a decrease in systolic and increase in diastolic pressures of up to 33% and 63% respectively, with a subsequent decrease in the pressure wave amplitude of up to 86%. Moreover, it was related to an increase in multidirectional intraluminal flows and transition of behaviour as 2 parallel vessels towards a vessel with a side-chamber. The model supports the extremely important role of wall elasticity as determinant of intraluminal pressures and flow patterns for DAD, and thus, the relevance of considering it during clinical assessment and computational modelling of the disease. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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24. Mycoplasma bovis infections in Swiss dairy cattle: a clinical investigation.
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Aebi, Marlis, van den Borne, Bart H. P., Raemy, Andreas, Steiner, Adrian, Pilo, Paola, and Bodmer, Michèle
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MYCOPLASMA bovis , *DAIRY cattle physiology , *DIAGNOSIS , *BOVINE mastitis , *PNEUMONIA diagnosis , *BLOOD proteins , *CATTLE , *CATTLE diseases - Abstract
Mycoplasma bovis causes mastitis in dairy cows and is associated with pneumonia and polyarthritis in cattle. The present investigation included a retrospective case-control study to identify potential herd-level risk factors for M. bovis associated disease, and a prospective cohort study to evaluate the course of clinical disease in M. bovis infected dairy cattle herds in Switzerland. Eighteen herds with confirmed M. bovis cases were visited twice within an average interval of 75 d. One control herd with no history of clinical mycoplasmosis, matched for herd size, was randomly selected within a 10 km range for each case herd. Animal health data, production data, information on milking and feedingmanagement, housing and presence of potential stress- factors were collected. Composite quarter milk samples were aseptically collected from all lactating cows and 5% of all animals within each herd were sampled by nasal swabs. Organ samples of culled diseased cows were collected when logistically possible. All samples were analyzed by real-time polymerase chain reaction (PCR). In case herds, incidence risk of pneumonia, arthritis and clinical mastitis prior to the first visit and incidence rates of clinical mastitis and clinical pneumonia between the two visits was estimated. Logistic regression was used to identify potential herd-level risk factors for M. bovis infection. In case herds, incidence risk of M. bovis mastitis prior to the first visit ranged from 2 to 15%, whereas 2 to 35% of the cows suffered from clinical pneumonia within the 12 months prior to the first herd visit. The incidence rates of mycoplasmal mastitis and clinical pneumonia between the two herd visits were low in case herds (0-0.1 per animal year at risk and 0.1-0.6 per animal year at risk, respectively). In the retrospective-case-control study high mean milk production, appropriate stimulation until milk-let-down, fore-stripping, animal movements (cattle shows and trade), presence of stress-factors, and use of a specific brand of milking equipment, were identified as potential herd-level risk factors. The prospective cohort study revealed a decreased incidence of clinical disease within three months and prolonged colonization of the nasal cavity by M. bovis in young stock. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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25. Frequency-dependent capacitors using paper.
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McGuyer, Bart H.
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CAPACITORS , *DIELECTRIC measurements , *ELECTRIC capacity , *DIELECTRICS - Abstract
Measurements of capacitors made with paper sheets reveal a significant decrease in capacitance with increasing frequency from 10 to 100,000 Hz, offering a simple demonstration of complex dielectric phenomena using common equipment. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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26. Gender gaps in primary school achievement: A decomposition into endowments and returns to IQ and non-cognitive factors.
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Golsteyn, Bart H. H. and Schils, Trudie
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PRIMARY schools , *ACADEMIC achievement , *MATHEMATICAL decomposition , *ENDOWMENTS , *ELEMENTARY schools - Abstract
In elementary school, girls typically outperform boys in languages and boys typically outperform girls in math. The determinants of these differences have remained largely unexplored. Using rich data from Dutch elementary schools, we decompose the differences in achievement into gender differences in endowments and returns to IQ and non-cognitive factors. This descriptive analysis is a thought experiment in which we show the consequences for school performance if girls and boys had similar resources and took similar advantage of these resources. Our findings indicate that gender differences in resources with respect to social and instrumental skills and need for achievement can explain part of the differences in performance. Boys seem to be better equipped with these resources. Additionally, boys and girls employ their skills differently. Girls take more advantage of their IQ than boys. Yet, the largest part of this parameter effect is left unexplained by IQ and non-cognitive factors. [ABSTRACT FROM AUTHOR]
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- 2014
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27. Questionnaire-based study to assess the association between management practices and mastitis within tie-stall and free-stall dairy housing systems in Switzerland.
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Gordon, Paz F., Van den Borne, Bart H. P., Reist, Martin, Kohler, Samuel, and Doherr, Marcus G.
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DISEASE prevalence , *DAIRY farms , *MASTITIS , *REGRESSION analysis - Abstract
Background Prophylactic measures are key components of dairy herd mastitis control programs, but some are only relevant in specific housing systems. To assess the association between management practices and mastitis incidence, data collected in 2011 by a survey among 979 randomly selected Swiss dairy farms, and information from the regular test day recordings from 680 of these farms was analyzed. Results The median incidence of farmer-reported clinical mastitis (ICM) was 11.6 (mean 14.7) cases per 100 cows per year. The median annual proportion of milk samples with a composite somatic cell count (PSCC) above 200,000 cells/ml was 16.1 (mean 17.3) %. A multivariable negative binomial regression model was fitted for each of the mastitis indicators for farms with tie-stall and free-stall housing systems separately to study the effect of other (than housing system) management practices on the ICM and PSCC events (above 200,000 cells/ml). The results differed substantially by housing system and outcome. In tie-stall systems, clinical mastitis incidence was mainly affected by region (mountainous production zone; incidence rate ratio (IRR) = 0.73), the dairy herd replacement system (1.27) and farmers age (0.81). The proportion of high SCC was mainly associated with dry cow udder controls (IRR = 0.67), clean bedding material at calving (IRR = 1.72), using total merit values to select bulls (IRR = 1.57) and body condition scoring (IRR = 0.74). In free-stall systems, the IRR for clinical mastitis was mainly associated with stall climate / temperature (IRR = 1.65), comfort mats as resting surface (IRR = 0.75) and when no feed analysis was carried out (IRR = 1.18). The proportion of high SSC was only associated with hand and arm cleaning after calving (IRR = 0.81) and beef producing value to select bulls (IRR = 0.66). Conclusions There were substantial differences in identified risk factors in the four models. Some of the factors were in agreement with the reported literature while others were not. This highlights the multifactorial nature of the disease and the differences in the risks for both mastitis manifestations. Attempting to understand these multifactorial associations for mastitis within larger management groups continues to play an important role in mastitis control programs. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
28. Concurrent and prospective effects of psychopathic traits on affective and cognitive empathy in a community sample of late adolescents.
- Author
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Brouns, Bart H. J., de Wied, Minet Annette, Keijsers, Loes, Branje, Susan, van Goozen, Stephanie H. M., and Meeus, Wim H. J.
- Subjects
- *
ADOLESCENT psychology , *ANALYSIS of variance , *CHI-squared test , *COMMUNITIES , *CONFIDENCE intervals , *STATISTICAL correlation , *EMPATHY , *EPIDEMIOLOGY , *LATENT structure analysis , *LONGITUDINAL method , *PSYCHOLOGICAL tests , *PATHOLOGICAL psychology , *RESEARCH funding , *SEX distribution , *T-test (Statistics) , *DATA analysis , *PARENT attitudes , *REPEATED measures design , *DESCRIPTIVE statistics , *ADOLESCENCE - Abstract
Background A deficit in affective rather than cognitive empathy is thought to be central to psychopathic traits. However, empirical evidence for empathy deficits in adolescents with psychopathic traits is limited. We investigated the concurrent and prospective effects of psychopathic traits on affective and cognitive trait empathy in late adolescence. Methods A community sample of 107 males and 126 females who were approximately 16-year olds at Time 1 participated in four annual waves. Sex-specific classes of adolescents' psychopathic traits were created using Latent Class Analyses. Subsequently, we investigated class differences in level and development of empathy. Results For both sexes, Latent Class Analyses produced two classes: one class with low and one with moderate levels of psychopathic traits. Consistent with our hypothesis, for both sexes, adolescents with moderate levels of psychopathic traits reported lower mean levels of affective empathy than adolescents with low levels of psychopathic traits. In addition, female adolescents with moderate psychopathic traits reported lower mean levels of cognitive empathy. Male adolescents showed a trend in this direction. No differences between classes were found in development of empathy, which increased over years. Conclusions This is the first study to show that male and female adolescents with higher levels of psychopathic traits have lower levels of affective empathy not only concurrently but also prospectively over a 3-year period. Females additionally showed a similar pattern on cognitive empathy. In this community sample, developmental results suggest that adolescents with higher levels of psychopathic traits have relative rather than absolute empathy deficits. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
29. Milchprotein‐Fouling auf PEEK als Wärmeübertragungsfläche: Belagbildung und Reinigbarkeit.
- Author
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Kiepfer, H. and Bart, H.-J.
- Published
- 2020
- Full Text
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30. Charakterisierung eines DN300 Pump‐Mixer‐Settlers.
- Author
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Wirz, D. and Bart, H.-J.
- Published
- 2020
- Full Text
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31. Separation, Hydrodynamics, and Joule Heating Effects in Continuous Annular Electrochromatography.
- Author
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Laskowski, R. and Bart, H.-J.
- Abstract
First experimental results of the transfer from an analytical batch electrochromatography to a continuous annular electrochromatographic process are presented. In order to study the electrochromatographic effects, hydrodynamics and functionality tests were investigated in a planar reference system. As stationary phase inside the annular gap, an inorganic C8 reverse-phase monolith prepared by an in situ sol-gel process was implemented. The generation of Joule heating during the process was determined by a contact-free thermal camera system. The volumetric flow rates of the electrolyte were detected by a gravimetric contact-free measurement method. Finally, a mixture of neutral test substances was used to evaluate the continuous separation efficiency and to fractionate the single substances under process-like conditions. The separation results were detected by an inline UV-Vis detection cell and the analysis of the single fractions was performed by an analytical electrochromatograph. The results indicate uniform electroosmotic flow as well as successful separation and fractioning of a neutral test mixture. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
32. Experimental and numerical investigation of binary coalescence: Liquid bridge building and internal flow fields.
- Author
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Eiswirth, R. T., Bart, H.-J., Ganguli, A. A., and Kenig, E. Y.
- Subjects
- *
NUMERICAL analysis , *BRIDGES , *TOLUENE , *BINARY metallic systems , *JETS (Fluid dynamics) , *MIXING - Abstract
In this work, we present the results of experimental and numerical investigation of the liquid bridge building and internal flows during a binary droplet-droplet coalescence event. A system consisting of two rising toluene droplets with different droplet radii that coalesce in surrounding water is considered. The growth of the liquid bridge between the two droplets during the coalescence event is found to be in the inertial regime, whereas the bridge radius grows in proportion to the square root of time. Further, the internal mixing of the two droplets is investigated. It is observed that when two droplets with the same radius coalesce, there is nearly no internal mixing within the first 40 ms after the coalescence start. In contrast, when two droplets with different radii coalesce, a liquid jet directed from the smaller to the larger droplet appears during the coalescence event. A good agreement between the experimental and numerical data is established. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
33. Determination of local velocity, energy dissipation and phase fraction with LIF- and PIV-measurement in a Kühni miniplant extraction column
- Author
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Hlawitschka, M.W. and Bart, H.-J.
- Subjects
- *
PARTICLE image velocimetry , *FLUORESCENCE , *LASER photochemistry , *EXTRACTION (Chemistry) , *SPEED , *ENERGY dissipation , *SUSPENSIONS (Chemistry) , *ELECTRON-hole droplets - Abstract
Abstract: Laser based measurement techniques were used to investigate the local velocities, the energy dissipation and the phase fraction inside a Kühni miniplant extraction column. The velocity field was determined with particle image velocimetry (PIV). The energy dissipation was obtained based on these measurements. The velocity measurements show that at extreme low dispersed phase flow the flow pattern alters extremely. The local time averaged phase fraction was measured with a laser induced fluorescence (LIF) system. It is shown that the accumulation underneath the stirrer has a high impact on the concentration of the dispersed phase in a single compartment. A higher rotational speed leads to a better distribution of droplets inside the column, whereas at lower stirring speed the droplets by-pass the impeller. Due to the shear force, especially near the stirrer outflow region, drop deformation and breakage occurs. [Copyright &y& Elsevier]
- Published
- 2012
- Full Text
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34. Experimental and numerical investigation of a free rising droplet
- Author
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Eiswirth, R.T., Bart, H.-J., Atmakidis, T., and Kenig, E.Y.
- Subjects
- *
DROPLETS , *TOLUENE , *COMPUTER simulation , *COMPUTATIONAL fluid dynamics , *EXTRACTION (Chemistry) , *LIQUID-liquid interfaces , *MATHEMATICAL optimization - Abstract
Abstract: A toluene droplet rising in a continuous aqueous phase is studied both experimentally and numerically. The experiments have been performed in a small scale, high-speed measuring unit with a high magnification device to image the process in all details. Numerical simulations are performed with the aid of the level set method implemented in the commercial CFD tool COMSOL Multiphysics 3.3a by COMSOL AB. A new technique for quantitative comparison of experimental and numerical results with respect to the droplet shape is presented. Both terminal velocity and droplet shape in experiments and simulations are found to be in excellent agreement. Based on the experimental and numerical data obtained, an improvement of an existing terminal velocity correlation is suggested. The adjusted correlation can be used for the design and optimisation of liquid–liquid extraction units. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
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35. "The Blood of Every Beast": Mormonism and the Question of the Animal.
- Author
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Welling, Bart H.
- Subjects
- *
ANIMALS in religions , *SOUL , *OBEDIENCE , *AGENT (Philosophy) , *AFTERLIFE (Mormon doctrine) , *BOOK of Mormon stories ,CHURCH of Jesus Christ of Latter-day Saints doctrines ,RELIGIOUS aspects - Abstract
The article presents the author's views on Mormonism and issues related to church doctrine regarding animals. The Latter Day Saint (LDS) movement's interpretation of scripture which teaches that animals should only killed if it is a matter of human survival because they are living souls is discussed. The association of amorality with the fears of being prey to wild animals and becoming animalistic in the Book of Mormon is mentioned. The concepts of obedience and agency in Mormon stories about eternal life are discussed.
- Published
- 2011
- Full Text
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36. Re-Annotation Is an Essential Step in Systems Biology Modeling of Functional Genomics Data.
- Author
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van den Berg, Bart H. J., McCarthy, Fiona M., Lamont, Susan J., and Burgess, Shane C.
- Subjects
- *
SYSTEMS biology , *GENETIC research , *GENOMICS , *BIOLOGICAL systems , *DNA microarrays , *SYSTEMS engineering , *SIMULATION methods & models , *SYSTEMS theory - Abstract
One motivation of systems biology research is to understand gene functions and interactions from functional genomics data such as that derived from microarrays. Up-to-date structural and functional annotations of genes are an essential foundation of systems biology modeling. We propose that the first essential step in any systems biology modeling of functional genomics data, especially for species with recently sequenced genomes, is gene structural and functional reannotation. To demonstrate the impact of such re-annotation, we structurally and functionally re-annotated a microarray developed, and previously used, as a tool for disease research. We quantified the impact of this re-annotation on the array based on the total numbers of structural- and functional-annotations, the Gene Annotation Quality (GAQ) score, and canonical pathway coverage. We next quantified the impact of re-annotation on systems biology modeling using a previously published experiment that used this microarray. We show that re-annotation improves the quantity and quality of structural- and functional-annotations, allows a more comprehensive Gene Ontology based modeling, and improves pathway coverage for both the whole array and a differentially expressed mRNA subset. Our results also demonstrate that re-annotation can result in a different knowledge outcome derived from previous published research findings. We propose that, because of this, re-annotation should be considered to be an essential first step for deriving value from functional genomics data. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
37. The stability of impacted morsellized bone grafts in a metal cage under dynamic loaded conditions: an in vitro reconstruction of a segmental diaphyseal bone defect.
- Author
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Bullens, Pieter H. J., Schreuder, Bart H. W., De Waal Malefijt, Maarten C., Veth, Rene P. H., Buma, Pieter, and Verdonschot, Nico
- Subjects
- *
BONE grafting , *INTRAMEDULLARY fracture fixation , *TREATMENT of fractures , *TRANSPLANTATION nursing ,TREATMENT of surgical complications - Abstract
Reconstructions of segmental diaphyseal bone defects with massive allografts are related to complications like nonunion and fractures. A reconstruction of these defects with a cage filled with an impacted morsellized bone graft could be an alternative. The bone graft in these cages should ideally be loaded to prevent resorption. Loading of morsellized bone grafts however can cause instability. The goal of this study was to assess the stability of an impacted morsellized bone graft in a cage under dynamic loaded conditions in an in vitro reconstruction of a segmental diaphyseal bone defect. The second goal was to assess the influence of cage type, washing of the graft and bone-cage fit. Two different cage types were filled with impacted morsellized bone graft. The grafts were used washed and unwashed and in variable bone-cage fit conditions. We recorded the bone graft deformation in the cage under dynamic loaded conditions. Stability appeared to be not very sensitive to the cage type and whether the bone chips were washed or not. However, quality of the fit of the cage with the bone segment was an important parameter and should be optimized during surgery. Morsellized impacted bone graft in a cage is stable in dynamic loaded conditions in an in vitro reconstruction of a segmental diaphyseal bone defect. We believe that this method of reconstruction is a promising alternative for the reconstruction of large diaphyseal bone defects and should be tested relative to its biological merits in animal experiments. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
38. Trace conditions for regular spectral behavior of vector-valued analytic functions
- Author
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Bart, H., Ehrhardt, T., and Silbermann, B.
- Subjects
- *
ANALYTIC functions , *BANACH algebras , *CAUCHY problem , *FREDHOLM operators , *IDEMPOTENTS , *VECTOR analysis , *SPECTRAL geometry - Abstract
Abstract: A new class of Banach algebra valued functions is identified for which the logarithmic residue with respect to a Cauchy domain vanishes (if and) only if the functions take invertible values in . Trace conditions and the extraction of elementary factors of the type play an important role. The class contains the Fredholm operator valued functions and the Banach algebra valued functions possessing a simply meromorphic resolvent as special instances. An example is given to show that new ground is covered and a long standing open problem is discussed from a fresh angle. [Copyright &y& Elsevier]
- Published
- 2009
- Full Text
- View/download PDF
39. Comparing gene annotation enrichment tools for functional modeling of agricultural microarray data.
- Author
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Van den Berg, Bart H. J., Thanthiriwatte, Chamali, Manda, Prashanti, and Bridges, Susan M.
- Subjects
- *
COMPUTATIONAL biology , *GENE expression , *ANNOTATIONS , *FUNCTIONAL analysis , *DNA microarrays , *INFORMATION retrieval - Abstract
The widespread availability of microarray technology has driven functional genomics to the forefront as scientists seek to draw meaningful biological conclusions from their microarray results. Gene annotation enrichment analysis is a functional analysis technique that has gained widespread attention and for which many tools have been developed. Unfortunately, most of these tools have limited support for agricultural species. Here, we evaluate and compare four publicly available computational tools (Onto-Express, EasyGO, GOstat, and DAVID) that support analysis of gene expression datasets in agricultural species. We use AgBase as the functional annotation reference for agricultural species. The selected tools were evaluated based on i) available features, usage and accessibility, ii) implemented statistical computational methods, and iii) annotation and enrichment performance analysis. Annotation was assessed using a randomly selected test gene annotation set and an experimental differentially expressed gene-set -- both from chicken. The experimental set was also used to evaluate identification of enriched functional groups. Comparison of the tools shows that they produce different sets of annotations for the two datasets and different functional groups for the experimental dataset. While DAVID, GOstat and Onto-Express annotate comparable numbers of genes, DAVID provides by far the most annotations per gene. However, many of DAVID's annotations appear to be redundant or are at very high levels in the GO hierarchy. The GOSlim distribution of annotations shows that GOstat, Onto-Express and EasyGO provide similar GO distributions to those found in AgBase while annotations from DAVID show a different GOSlim distribution, again probably due to duplication and many non-specific terms. No consistent trends were found in results of GO term over/under representation analysis applied to the experimental data using different tools. While GOstat, David and Onto-Express could retrieve some significantly enriched terms, EasyGO did not show any significantly enriched terms. There was little agreement about the enriched terms identified by the tools. Conclusion: Different tools for functionally annotating gene sets and identifying significantly enriched GO categories differ widely in their results when applied to a test annotation gene set and an experimental dataset from chicken. These results emphasize the need for care when interpreting the results of such analysis and the lack of standardization of approaches. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
40. Process intensification with reactive extraction columns
- Author
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Bart, H.-J., Drumm, C., and Attarakih, M.M.
- Subjects
- *
LIQUID-liquid interfaces , *EXTRACTION (Chemistry) , *SOLVENTS , *SURFACE active agents - Abstract
Abstract: Process intensification of liquid–liquid extraction columns using reactive extraction systems and population balance modelling approaches are discussed. As a means of process intensification, bulk organic solvents could be replaced by chemically reactive organic phases in order to enhance the extraction efficiency and selectivity. Moreover, extraction of speciality materials could be achieved by using either ionic liquids or solvent phases containing a controlled quantity of surfactants. For deep insight and hence better performance of liquid–liquid extraction columns, population balance modelling approaches can be utilized for process intensification, since the model parameter estimation is possible in small lab-scale devices instead of pilot plant experiments as it is state of the art. A significantly reduced time-to-market period and savings in costs will result. A further improvement can be achieved when the population balance model is coupled to computational fluid dynamics (CFD) where detailed flow fields and turbulent energy dissipation could be obtained. This will foster high-precision engineering, especially with large-scale industrial units. [Copyright &y& Elsevier]
- Published
- 2008
- Full Text
- View/download PDF
41. Emulsion liquid membrane extraction of zinc by a hollow-fiber contactor
- Author
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Fouad, E.A. and Bart, H.-J.
- Subjects
- *
EXTRACTION (Chemistry) , *EXTRACTION techniques , *SOLUTION (Chemistry) , *ZINC - Abstract
Abstract: Emulsion liquid membranes (ELMs) can contribute to process intensification of zinc extraction, by significantly reducing the solvent and carrier requirements in comparison with conventional solvent extraction. Di(2-ethylhexyl)phosphoric acid (D2EHPA) was used as a highly selective carrier for the transport of zinc ions through the emulsified liquid membrane. The hollow-fiber extractor appears to offer significant advantages over conventional liquid–liquid contactors for this separation because emulsion leakage and swell are practically eliminated even when treating high concentration feeds. Various hydrodynamic and chemical parameters, such as variation in feed pH; zinc concentration in feed; variation in concentrations of D2EHPA; variation in feed/emulsion volume ratios and variation in feed and emulsion flow rates, were investigated. The content of sulfuric acid as an internal did not show in the studied range any significant influence on zinc extraction through the ELM, although a minimum hydrogen ion concentration is suggested in the internal aqueous solution to ensure acidity gradient between both aqueous phases to promote the permeation of zinc ions toward the internal phase. The experimental mass-transfer coefficients have shown a stronger dependence on hydrodynamic conditions in both the external feed phase and emulsion among the parameters studied. For emulsion flow rate, mass-transfer coefficient increased from 16.3×10−6 m/s at 200ml/min to 31.2×10−6 m/s at 640ml/min. Significant increasing in mass-transfer coefficient observed with increasing aqueous flow rate from 9.7×10−6 m/s at 170ml/min to 37.2×10−6 m/s at 740ml/min. The overall mass-transfer coefficient increases from 12×10−6 m/s at 2% D2EHPA to 28×10−6 m/s at 8% D2EHPA. This means that this process is chemically controlled and the interfacial resistance has a more significant role in the extraction of zinc by emulsion liquid membrane through hollow-fiber contactor. From the results obtained, it seems that the diffusion processes in aqueous feed phase and the membrane phase have the same importance as the chemical process. [Copyright &y& Elsevier]
- Published
- 2008
- Full Text
- View/download PDF
42. Separation of Zinc by a Non-dispersion Solvent Extraction Process in a Hollow Fiber Contactor.
- Author
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Fouad, E. A. and Bart, H.-J.
- Subjects
- *
TEXTILE research , *TEXTILES , *TEXTILE industry , *PHOSPHOINOSITIDES , *PHOSPHORIC acid , *HYDROGEN-ion concentration , *MASS transfer , *ZINC , *EXTRACTION (Chemistry) - Abstract
A process for recovery of zinc from acid solution with di(2-ethyl hexyl phosphoric acid) (D2EHPA) dissolved in iso-dodecane was carried out at 20°C in a countercurrent tubular membrane extractor using a hollow fiber as solid support. Experiments were performed at different aqueous metal concentrations (0.1-l.0g/L), pH 0.1-2.1, and D2EHPA concentrations (2-8 v%). It was found that both the flux of metal and the extraction extent was highly influenced by the extractant concentration and the pH of the feed solution. Overall mass transfer coefficients were determined and related to the tube side, the membrane, and the shell side mass transfer by varying the aqueous flow rate (0.38-0.80 L/min) and organic flow rate (0.22-0.57 L/min) in countercurrent flow. The overall mass transfer coefficient for zinc extraction ranged from 6.2 × 10-6 m/s to 25.3 × 10-6 m/s. It was concluded that extraction kinetics were a major contributor to the overall resistance to mass transfer. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
43. A practical instrument to explore patients' needs in palliative care: the Problems and Needs in Palliative Care questionnaire -- short version.
- Author
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Osse, Bart H. P., Vernooij-Dassen, Myrra J. F. J., Schadé, Egbert, and Grol, Richard P. T. M.
- Subjects
- *
MEDICAL needs assessment , *PALLIATIVE treatment , *NEEDS assessment , *QUESTIONNAIRES , *HEALTH planning - Abstract
Objective: Short and convenient checklists are necessary tools to support and structure needs assessments in daily palliative practice. This study aims to develop a short version of the Problems and Needs in Palliative Care questionnaire (PNPC-sv); a self-report questionnaire for patients covering all dimensions of palliative care, to investigate their problems and (unmet) needs. Methods: The original Problems and Needs in Palliative Care questionnaire (PNPC) instrument is a comprehensive checklist of problems and needs for palliative care, and has shown validity and reliability. With its 90 items, however, it is not always practical. Thus it was abridged to a short version with 33 items. The validity and reliability are established with its item response, its internal consistency, and with its correlations with the original PNPC and with European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Core 30 and COOP/WONCA quality-of-life measures. A secondary analysis was done with data from 94 patients with metastatic cancer who had completed the long version. Results: Each item in the PNPC represents a problem relevant to 25% of the patients or more. High correlations of PNPC-sv and PNPC domains demonstrate construct validity. The dimension reliability was satisfactory (Cronbach's α > 0.70), while two problem-aspect domains were less coherent. The PNPC-sv domains show convergent validity with corresponding health-related quality-of-life domains. Conclusion: The PNPC-sv is a concise, patient-centred tool that helps to identify the problems affecting the patient's quality of life and needs for care. It identifies prevalent needs for care and appears reliable. Further research should study the clinical effects of integrating the questionnaire into daily palliative-care practice. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
44. Optimal prepayment of Dutch mortgages.
- Author
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Kuijpers, Bart H. M. and Schotman, Peter C.
- Subjects
- *
MORTGAGES , *PREPAYMENT of debts , *MORTGAGE loans , *HEURISTIC - Abstract
Valuation of the prepayment option in Dutch mortgages is complicated. In the Netherlands, mortgagors are not allowed to prepay the full mortgage loan without a compensating penalty. Only a limited amount of the initial mortgage loan can be prepaid penalty-free. We introduce a general model formulation for the valuation of limited callable mortgages, based on binomial trees. This model can be used for determining both the optimal prepayment strategy and the value of embedded prepayment options. For some mortgage types the prepayment option can be valued exactly, whereas other types require approximative methods for efficient valuation. The heuristic we propose here determines the prepayment option value efficiently and accurately for general mortgage types. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
45. Monetary Valuation of Emissions in Implementing Environmental Policy: The Reduction Cost Approach Based upon Policy Targets.
- Author
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Davidson, Marc D., Boon, Bart H., and Van Swigchem, Jessica
- Subjects
- *
COST effectiveness , *ENVIRONMENTAL policy , *AIR pollution , *EMISSIONS (Air pollution) , *LINEAR programming , *GOVERNMENT policy , *CONTINGENT valuation , *ENVIRONMENTAL auditing , *ENVIRONMENTAL impact charges - Abstract
At various levels of environmental policy making there is a demand to translate polluting emissions into monetary units. In the so-called reduction cost approach, based upon policy targets, polluting emissions are expressed in monetary terms by determination of the marginal unit reduction cost at the emission target level. This approach provides shadow prices for emissions by which it can be established whether a certain measure or technology belongs to the most efficient set of measures by which the policy targets can be reached. This article argues that, if clear (generic) government targets such as national emission reduction targets exist for an emission, shadow prices derived by this method are to be preferred to shadow prices derived by other methods for decisions at the project (implementation) level. By application of the reduction cost approach, implementation decisions can be made that are both cost-effective and consistent with government policy. [ABSTRACT FROM AUTHOR]
- Published
- 2005
- Full Text
- View/download PDF
46. Schur complements and state space realizations
- Author
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Bart, H., Gohberg, I., Kaashoek, M.A., and Ran, A.C.M.
- Subjects
- *
ALGEBRAIC spaces , *SYSTEMS theory , *NUMERICAL analysis , *ALGEBRA - Abstract
Abstract: Motivated by state space realizations of transfer functions from system theory, a number of operations on Schur complements are introduced and studied. These operations are equivalence, extension, multiplication, inversion, and factorization. Together they form an algebraic framework which is of independent interest, and also useful in solving problems in analysis. [Copyright &y& Elsevier]
- Published
- 2005
- Full Text
- View/download PDF
47. Mass transfer into droplets undergoing reactive extraction
- Author
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Mörters, M. and Bart, H.-J.
- Subjects
- *
MASS transfer , *EXTRACTION (Chemistry) - Abstract
The mass transfer into droplets in metal extraction is investigated in the system ZnSO4–H2SO4/di(2ethylhexyl)phosphoric acid in isododecane. Results of equilibrium measurements and stirred cell experiments are described in a mathematical model based on gradients of chemical potential. Concentration profiles measured with Laser Induced Fluorescence technology were calculated with the Maxwell–Stefan equations. Diffusion coefficients were estimated using the Wilke and Chang equation. Additional eddy diffusion coefficients measured in single droplet experiments in a venturi tube are described with different models known from literature. Whereas equilibria and mass transfer into droplets in stagnant conditions can be calculated with good agreement with the experimental results, none of the known models describes eddy diffusion in reactive extraction occurring in free moving droplets sufficiently well over a broad concentration range. [Copyright &y& Elsevier]
- Published
- 2003
- Full Text
- View/download PDF
48. Influence of high-frequency AC fields on mass transfer in solvent extraction
- Author
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Gneist, G. and Bart, H.-J.
- Subjects
- *
MASS transfer , *SOLVENT extraction , *ELECTRIC fields , *ELECTRON-hole droplets - Abstract
The influence of high-frequency AC fields on mass transfer from aqueous pendant and moving droplets into a continuous organic phase is investigated. Results are compared with those of applied DC voltage and those with no electric field present. Experiments are carried out in a low viscosity water–toluene system with acetone as the solute and in a high viscosity water–isotridecanol system with 1-propanol as the solute. AC and DC effects on Marangoni phenomena at pendant droplets are studied. High-frequency AC voltage is found to depress Marangoni phenomena whereas DC voltage enhances or initially induces Marangoni phenomena. Mass transfer from moving droplets could not be enhanced by the use of electric fields (AC or DC) at constant droplet size. The experimentally achieved concentration–time profiles are compared with those calculated from different mass transfer models for single droplets. [Copyright &y& Elsevier]
- Published
- 2003
- Full Text
- View/download PDF
49. Optimal moving and fixed grids for the solution of discretized population balances in batch and continuous systems: droplet breakage
- Author
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Attarakih, M.M., Bart, H.-J., and Faqir, N.M.
- Subjects
- *
POPULATION , *DIFFERENTIAL equations - Abstract
The numerical solution of droplet population balance equations (PBEs) by discretization is known to suffer from inherent finite domain errors (FDE). Tow approaches that minimize the total FDE during the solution of discrete droplet PBEs using an approximate optimal moving (for batch) and fixed (for continuous systems) grids are introduced. The optimal grids are found based on the minimization of the total FDE, where analytical expressions are derived for the latter. It is found that the optimal moving grid is very effective for tracking out steeply moving population density with a reasonable number of size intervals. This moving grid exploits all the advantages of its fixed counterpart by preserving any two pre-chosen integral properties of the evolving population. The moving pivot technique of Kumar and Ramkrishna (Chem. Eng. Sci. 51 (1996b) 1333) is extended for unsteady-state continuous flow systems, where it is shown that the equations of the pivots are reduced to that of the batch system for sufficiently fine discretization. It is also shown that for a sufficiently fine grid, the differential equations of the pivots could be decoupled from that of the discrete number density allowing a sequential solution in time. An optimal fixed grid is also developed for continuous systems based on minimizing the time-averaged total FDE. The two grids are tested using several cases, where analytical solutions are available, for batch and continuous droplet breakage in stirred vessels. Significant improvements are achieved in predicting the number densities, zero and first moments of the population. [Copyright &y& Elsevier]
- Published
- 2003
- Full Text
- View/download PDF
50. A Meeting With Old Ben: Seeing and Witing Nature in Faulkner's Go Down, Moses.
- Author
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Welling, Bart H.
- Subjects
- *
ECOCRITICISM - Abstract
Analyzes the content of the book 'Go Down, Moses,' by William Faulkner. Theme of the story; Focus on ecocriticism; Concerns over the interaction of the humans in the environment.
- Published
- 2002
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