Browsing
     by title


0-9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

or enter first few letters:   
OK
Full Text
Peer Reviewed
See detailDirect CO2 advection measurements and the night flux problem
Aubinet, Marc ULg; Feigenwinter, Christian

in Agricultural and Forest Meteorology (2010), 150(5), 651-654

Detailed reference viewed: 63 (3 ULg)
Full Text
Peer Reviewed
See detailDirect control service from residential heat pump aggregation with specified payback
Georges, Emeline ULg; Cornélusse, Bertrand ULg; Ernst, Damien ULg et al

in Proceedings of the 19th Power Systems Computation Conference (PSCC) (2016, June)

This paper addresses the problem of an aggregator controlling residential heat pumps to offer a direct control flexibility service. The service is defined by a 15 minute power modulation, upward or ... [more ▼]

This paper addresses the problem of an aggregator controlling residential heat pumps to offer a direct control flexibility service. The service is defined by a 15 minute power modulation, upward or downward, followed by a payback of one hour and 15 minutes. The service modulation is relative to an optimized baseline that minimizes the energy costs. The potential amount of modulable power and the payback effect are computed by solving mixed integer linear problems. Within these problems, the building thermal behavior is modeled by an equivalent thermal network made of resistances and lumped capacitances whose parameters are identified from validated models. Simulations are performed on 100 freestanding houses. For an average 4.3 kW heat pump, results show a potential of 1.2 kW upward modulation with a payback of 600 Wh and 150 Wh of overconsumption. A downward modulation of 500 W per house can be achieved with a payback of 420 Wh and 120 Wh of overconsumption. [less ▲]

Detailed reference viewed: 68 (14 ULg)
Full Text
Peer Reviewed
See detailDirect costs of hip fractures in patients over 60 years of age in Belgium.
Reginster, Jean-Yves ULg; Gillet, Philippe ULg; Ben Sedrine, Wafa ULg et al

in PharmacoEconomics (1999), 15(5), 507-514

OBJECTIVE: Osteoporosis-related costs are now considered a major burden for health authorities in most developed countries. An accurate and exhaustive evaluation of these costs would be a major ... [more ▼]

OBJECTIVE: Osteoporosis-related costs are now considered a major burden for health authorities in most developed countries. An accurate and exhaustive evaluation of these costs would be a major contribution to health economic studies evaluating the efficiency of screening and prevention strategies. Osteoporosis is the most frequent underlying cause of femoral neck fractures in the elderly; these fractures weigh heavily on healthcare budgets. However, in Belgium, very few data on the financial burden of hip fractures are available and no updated estimates have been made. The goal of this paper is to estimate the direct medical expenditures associated with hip fractures in Belgium in 1996. DESIGN AND SETTING: This 1-year population-based cross-sectional study is conducted from the social security perspective. The target population in this study are men and women aged 60 years and over. PATIENTS AND PARTICIPANTS: We selected patients who had been hospitalised for a hip fracture during the year 1996 who were also affiliated with a registered social security organisation (covering 25% of the Belgian population). The sample constituted 2374 patients. INTERVENTIONS: For each of these patients, we collected an exhaustive and detailed list of healthcare resource use as well as nursing home admissions following the hip fracture event. Cost items investigated in the analysis were inpatient hospital costs and outpatient costs. Mean annual costs per case recorded in the sample were then extrapolated to the whole country on the basis of an exhaustive list of diagnoses having lead to all countrywide hospitalisations (1,700,000 hospital stays/year). MAIN OUTCOME MEASURES AND RESULTS: The mean hospital inpatient costs for hip fracture were evaluated at 332,148 Belgian francs (BeF) [$US8977] per case and BeF4,367,746,200 ($US118,047,194) for the whole country (10 million inhabitants). Patients with a hip fracture experienced an annual BeF27,825 ($US752) extra outpatient cost during the year following this fracture event, after correcting for costs related to additional comorbidity already present before the hip fracture. Finally, after a proximal femoral neck fracture, the rate of nursing home admission was higher, both for men and women at any age compared with age- and gender-matched population. CONCLUSIONS: With a total cost (acute hospital and outpatient costs) of BeF4,667,894,950 ($US126,159,323) per year in Belgium, proximal femoral neck fracture should be considered a major health economic problem and appropriate measures to prevent this disease should be rapidly undertaken. [less ▲]

Detailed reference viewed: 69 (15 ULg)
Peer Reviewed
See detailDirect criteria for structure preserving models of electric power systems
Van Cutsem, Thierry ULg; Toumi, B; Xue, Y et al

in Proc. IFAC Symposium on Power Systems and Power Plant control (1986)

Detailed reference viewed: 15 (0 ULg)
Full Text
Peer Reviewed
See detailDirect detection of Aspergillus and azole resistance of Aspergillus fumigatus on broncho-alveolar lavage fluid. Validation of a new Aspergillus real-time PCR
Chong, Ga-Lai; Van de Sande, Wendy; Dingemans, Gijs et al

in Journal of Clinical Microbiology (2015)

Introduction Azole resistance in Aspergillus fumigatus is increasingly reported. We describe the validation of AsperGenius® , a new multiplex real-time polymerase chain reaction (PCR) assay consisting of ... [more ▼]

Introduction Azole resistance in Aspergillus fumigatus is increasingly reported. We describe the validation of AsperGenius® , a new multiplex real-time polymerase chain reaction (PCR) assay consisting of two multiplex real-time PCRs: one which identifies the clinically relevant Aspergillus species, and one which detects the TR34, L98H, T289A, Y121F mutations in CYP51A and differentiates susceptible from resistant A. fumigatus strains. Methods The diagnostic performance was tested on 37 bronchoalveolar lavage (BAL) samples from haematology patients and on 40 BAL samples from intensive care unit (ICU) patients using BAL galactomannan ≥1.0 or positive culture as the gold standard for the presence of Aspergillus. Results In the haematology and ICU groups combined, there were 22 BAL samples with IA (2 proven, 9 probable and 11 non-classifiable). Nineteen of the 22 BAL samples were positive according to the gold standard. The optimal cycle threshold value for the presence of Aspergillus was <36. Sixteen of the 19 BAL samples had a positive PCR (2 Aspergillus species and 14 A. fumigatus). This resulted in a sensitivity, specificity, positive and negative predictive value of 88.9%, 89.3%, 72.7% and 96.2% for the haematology group and 80.0%, 93.3%, 80.0% and 93.3% in the ICU group, respectively. The CYP51A real-time PCR confirmed 12 wildtype and 2 resistant strains (1 TR34/L98H and 1 TR46/Y121F/T289A mutant). Conclusion The AsperGenius® multiplex real-time PCR allows for a sensitive and fast detection of Aspergillus species directly in BAL samples. More importantly, this assay detects and differentiates wildtype from resistant strains even if BAL cultures remained negative. [less ▲]

Detailed reference viewed: 24 (4 ULg)
Full Text
See detailDirect determination of physical parameters for main sequence stars
Rabus, Markus; Lachaume, Regis; Brahm, Rafael et al

in Protostars and Planets VI (2013, July 01)

The environment of planetary formation and evolution is mainly characterized by its host star's physical properties. Until recently most fundamental stellar parameters, like e. g. the star's radius and ... [more ▼]

The environment of planetary formation and evolution is mainly characterized by its host star's physical properties. Until recently most fundamental stellar parameters, like e. g. the star's radius and effective temperature, have only been estimated indirectly; but with advances in interferometric observing technique it is now possible to obtain a direct estimate of them. In this poster we present preliminary results from measured interferometric fringe visibilities of main-sequence stars. These visibilities were collected using the four-beam combiner VLTI/PIONIER instrument and the 1.8m Auxiliary Telescopes (ATs) in A1-G1-K0-J3 quadruplet configuration. We bracketed each science target with different calibrators to ensure reducing the systematic errors in our data. For each target star, the data reduction was performed several hundred times, each time randomizing the set of fringes by the bootstrap method and the calibrators' diameters. This allowed us to take into account error correlations across spectral channels, between consecutive observations, and overnight. Each result was least-squares fitted by a uniform disc, yielding a value for the target's diameter. From the distribution of diameters we assessed the statistical error in the respective measurement. Using the HIPPARCOS parallax we estimated the distance and obtained the star's linear radius. Combined with the bolometric flux we obtained a direct quantification of the effective temperature from the Stefan-Boltzmann equation. Finally, these direct determinations of stellar radii and effective temperatures enable us to better characterize planets around main-sequence stars. [less ▲]

Detailed reference viewed: 30 (5 ULg)
Full Text
Peer Reviewed
See detailDirect determination of tagitinin C in Tithonia diversifolia leaves by on-line coupling of supercritical carbon dioxide extraction to FT-IR spectroscopy by means of optical fibres
Ziemons, Eric ULg; Barillaro, Valéry; Rozet, Eric ULg et al

in Talanta (2007), 71(2), 911-917

Supercritical fluid extraction (SFE) with carbon dioxide as extraction medium was on-line coupled to a FT-IR spectrometer equipped with a Mercury Cadmium Telluride (MCT) detector using a tailor-made high ... [more ▼]

Supercritical fluid extraction (SFE) with carbon dioxide as extraction medium was on-line coupled to a FT-IR spectrometer equipped with a Mercury Cadmium Telluride (MCT) detector using a tailor-made high-pressure fibre optic flow cell. This method was optimised and developed for the monitoring in real time and the quantification of dynamic extractions of tagitinin C from Tithonia.diversifolia leaves. In order to demonstrate the method ability to allow the direct quantification of tagitinin C in the extract medium the standard addition method was used. The area integration Of Curves obtained by plotting the absorbance of the highly specific C=O stretching vibration at 1668 cm(-1) versus time (i.e. extractograms) was used as instrumental response. The SFE/FT-IR process was successfully validated using the accuracy profile as decision tool. On this basis, a linear regression model was chosen for the calibration curve. The relative standard deviation for repeatability and intermediate precision were between 0.8 and 3.1 %, respectively. Moreover, the method was found to be accurate as the two-sided 95% beta-expectation tolerance interval did not exceed the acceptance limits of 85 and 115% on the analytical range investigated (500-2500 mu g of added amount of tagitinin Q. The proposed method allowed the non-destructive extraction of tagitinin C and its on-line quantitative determination in less than 25 min thus facilitating the subsequent experiments or the pharmacological studies performed on this compound. [less ▲]

Detailed reference viewed: 101 (3 ULg)
Full Text
Peer Reviewed
See detailDirect determination of the NaF/AlF3 molar ratio by raman spectroscopy in NaF-AlF3-CaF2 melts at 1000° C
Malherbe, Cédric ULg; Gilbert, Bernard ULg

in Analytical Chemistry (2013)

For the last 40 years, Raman spectroscopy has been very useful in investigating the structure of corrosive molten salts, such as the cryolite-based melts widely used as electrolyte in the Hall-Heroult ... [more ▼]

For the last 40 years, Raman spectroscopy has been very useful in investigating the structure of corrosive molten salts, such as the cryolite-based melts widely used as electrolyte in the Hall-Heroult process. Even if this process remains the most economically efficient for metallic aluminum electro-production, it suffers from a high energy loss, which is dependent on the melt composition. Therefore, controlling the chemical composition of the electrolyte is essential. The present paper proposes to apply Raman spectroscopy for the direct determination of the NaF-AlF3 molar ratio in NaF-AlF3-CaF2-based melts. Despite the experimental difficulties, a calibration curve based on equilibria taking place in the melt has been developed and the procedure has been successfully compared to industrial samples of known compositions. The possible exportation of the laboratory scale procedure to an industrial environment application for the control of the Hall-Heroult process is finally discussed. [less ▲]

Detailed reference viewed: 31 (12 ULg)
Full Text
See detailDirect differentiation of time integrators for multibody systems with absolute rotations
Bruls, Olivier ULg; Eberhard, Peter

in Proceedings of the ECCOMAS Thematic Conference - Multibody Dynamics 2007 (2007)

Gradient-based optimization methods require efficient algorithms to compute the sensitivities of the simulation results with respect to design parameters. Compared to finite difference schemes, the direct ... [more ▼]

Gradient-based optimization methods require efficient algorithms to compute the sensitivities of the simulation results with respect to design parameters. Compared to finite difference schemes, the direct differentiation technique leads to a significant reduction in the computational cost of the sensitivities while keeping a good accuracy. In particular, this paper focuses on the optimization of multibody systems with large rotations. In this framework, two versions of the generalized-alpha time integration scheme are considered: the first one is based on a parameterized treatment of the rotations, whereas the second one is formulated in a geometric setting. We show that the sensitivity analysis is much simpler and computationally more efficient in the second case than in the first case. The performance of both algorithms is compared for a numerical example. [less ▲]

Detailed reference viewed: 23 (3 ULg)
See detailDirect displacement-based seismic design of an irregular frame - Case study
Massena, B.; Bento, R.; Degée, Hervé ULg

Report (2008)

Detailed reference viewed: 79 (7 ULg)
Full Text
Peer Reviewed
See detailA Direct Dopaminergic Control of Aromatase Activity in the Quail Preoptic Area
Baillien, M.; Balthazart, Jacques ULg

in Journal of Steroid Biochemistry & Molecular Biology (1997), 63(1-3, Sep-Oct), 99-113

In the quail preoptic area (POA) anatomical and pharmacological data suggest that catecholamines may be implicated in the control of testosterone (T) aromatization into estrogens. The biochemical ... [more ▼]

In the quail preoptic area (POA) anatomical and pharmacological data suggest that catecholamines may be implicated in the control of testosterone (T) aromatization into estrogens. The biochemical mechanism(s) mediating this control of the enzyme activity is (are) however unexplored. The present studies were carried out to investigate whether the catecholamines, dopamine (DA) and norepinephrine (NE) are able to directly affect aromatase activity (AA) measured during in vitro incubations of POA homogenates. AA was quantified in the POA-hypothalamus of adult male Japanese quail by measuring the tritiated water production from [1beta-3H]-androstenedione. Enzyme activity was linear as a function of the incubation time and of the protein content of homogenates. It exhibited a typical Michaelis-Menten kinetics, with an apparent Km of 2.8 nM and a Vmax of 266.6 fmol h(-1) mg wet weight(-1). AA was then measured at a substrate concentration of 25 nM in the presence of catecholamines and some of their receptor agonists or antagonists, at two concentrations, 10(-3) and 10(-6) M. Norepinephrine and prazosin (alpha1-adrenergic antagonist) had no or very limited effects on AA at both concentrations. In contrast, DA and some D1 and/or D2 receptor agonists (apomorphine[D1/D2], SKF-38393 [D1] and RU-24213 [D2]) depressed AA by 40 to 70% at the 10(-3) M concentration. One D2 receptor antagonist also produced a major inhibition of AA (sulpiride) while other antagonists either had no significant effect or only produced moderate decreases in enzyme activity (SCH-23390 [D1], spiperone [D2], pimozide [D2]) as did two DA indirect agonists, amfonelic acid and nomifensine. The inhibitory effect of the agonists was not antagonized by the less active antagonists, SCH-23390 [D1] or spiperone [D2]. Taken together these results suggest that the inhibitory effects do not involve specific binding of DA or its agonists/antagonists to dopaminergic receptors mediating changes in cAMP concentration. This conclusion is also supported by the observation that addition of dibutyryl cAMP did not change brain AA. It appears more likely that DA and dopaminergic drugs inhibit AA by a direct effect on the enzyme, as suggested by the competitive nature of DA and SKF-38393 inhibition of AA (Ki's of 59 and 84 microM, respectively). The functional significance of this effect should still be demonstrated but this mechanism may represent an important physiological pathway through which neurotransmitters could rapidly affect steroid-dependent processes such as the neural synthesis of estrogens. This would provide a mean by which environmental stimuli could affect reproductive behavior and physiology. [less ▲]

Detailed reference viewed: 17 (2 ULg)
Full Text
Peer Reviewed
See detailDirect effect of ice sheets on terrestrial bicarbonate, sulphate and base cation fluxes during the last glacial cycle: minimal impact on atmospheric CO2 concentrations
Tranter, Martyn; Huybrechts, Philippe; Munhoven, Guy ULg et al

in Chemical Geology (2002), 190(1-4), 33-44

Chemical erosion in glacial environments is normally a consequence of chemical weathering reactions dominated by sulphide oxidation linked to carbonate dissolution and the carbonation of carbonates and ... [more ▼]

Chemical erosion in glacial environments is normally a consequence of chemical weathering reactions dominated by sulphide oxidation linked to carbonate dissolution and the carbonation of carbonates and silicates. Solute fluxes from small valley glaciers are usually a linear function of discharge. Representative glacial solute concentrations can be derived from the linear association of solute flux with discharge. These representative glacial concentrations of the major ions are similar to 25% of those in global river water. A 3-D thermomechanically coupled model of the growth and decay of the Northern Hemisphere ice sheets was used to simulate glacial runoff at 100-year time steps during the last glacial cycle (130 ka to the present). The glacially derived fluxes of major cations, anions and Si over the glaciation were estimated from the product of the glacial runoff and the representative glacial concentration. A second estimate was obtained from the product of the glacial runoff and a realistic upper limit for glacial solute concentrations derived from theoretical considerations. The fluxes over the last glacial cycle are usually less than a few percent of current riverine solute fluxes to the oceans. The glacial fluxes were used to provide input to an oceanic carbon cycling model that also calculates changes in atmospheric CO2. The potential change in atmospheric CO2 concentrations over the last glacial cycle that arise from perturbations in glacial solute fluxes are insignificant, being < 1 ppm. [less ▲]

Detailed reference viewed: 12 (2 ULg)
Peer Reviewed
See detailA direct enzyme-linked immunosorbent assay (Elisa) for antibodies to enterobacterial score glycolipid and lipid A. Results in Healthy Subjects and in Patients Infected by Gram-Negative Bacteria
Nys, Monique ULg; Damas, Pierre ULg; Damas, François ULg et al

in Medical Microbiology & Immunology (1987), 176(5), 257-271

We have developed an ELISA for IgM and IgG antibodies to the core glycolipid (CGL) of the Re mutant Salmonella minnesota R 595, and to lipid A. Anti-CGL antibodies have been detected in sera from 37% of ... [more ▼]

We have developed an ELISA for IgM and IgG antibodies to the core glycolipid (CGL) of the Re mutant Salmonella minnesota R 595, and to lipid A. Anti-CGL antibodies have been detected in sera from 37% of healthy blood donors, whereas anti-lipid A activities were found in 13% of individuals only. The anti-CGL and anti-lipid A activities were examined in patients in a surgical intensive care unit, selected on the basis of a definite risk of infectious complications due to Gram-negative bacteria. Of the patients who developed such infections, the rate of favourable outcome was significantly higher in patients with either stable positive or increasing anti-CGL activities than in patients found to be negative. Our results provide clear evidence that anti-CGL antibodies contribute to host defence against various Gram-negative bacteria. [less ▲]

Detailed reference viewed: 13 (1 ULg)
Full Text
Peer Reviewed
See detailDirect estimation of sieve size distributions from 2-D image analysis of sand particles
Pirard, Eric ULg; Vergara, Nicolas; Chapeau, Vincent

in Proceedings PARTEC 2004 (2004)

Detailed reference viewed: 67 (9 ULg)
Full Text
Peer Reviewed
See detailDirect evidence for ferroelectric polar distortion in ultrathin lead titanate perovskite films
Despont, L.; Koitzsch, C.; Clerc, F. et al

in Physical Review. B, Condensed Matter and Materials Physics (2006), 73

X-ray photoelectron diffraction is used to directly probe the intracell polar atomic distortion and tetragonality associated with ferroelectricity in ultrathin epitaxial PbTiO3 films. Our measurements ... [more ▼]

X-ray photoelectron diffraction is used to directly probe the intracell polar atomic distortion and tetragonality associated with ferroelectricity in ultrathin epitaxial PbTiO3 films. Our measurements, combined with ab initio calculations, unambiguously demonstrate noncentrosymmetry in films a few unit cells thick, imply that films as thin as three unit cells still preserve a ferroelectric polar distortion, and also show that there is no thick paraelectric dead layer at the surface. [less ▲]

Detailed reference viewed: 14 (0 ULg)
Full Text
Peer Reviewed
See detailDirect evidence for gray seal (Halichoerus grypus) predation and scavenging on harbor porpoises (Phocoena phocoena)
Bouveroux, T.; Kiszka, J.; Heithaus, R. et al

in Marine Mammal Science (2014)

Detailed reference viewed: 26 (2 ULg)
Full Text
Peer Reviewed
See detailDirect Evidence of Free Radical Production after Ischaemia and Reperfusion and Protective Effect of Desferrioxamine: Esr and Vitamin E Studies
Defraigne, Jean-Olivier ULg; Detry, Olivier ULg; Pincemail, Joël ULg et al

in European Journal of Vascular Surgery (1994), 8(5), 537-43

After surgical renal revascularisation, warm renal ischaemia due to renal artery cross-clamping contributes to postoperative renal dysfunction. After reperfusion, free radicals are thought to be a ... [more ▼]

After surgical renal revascularisation, warm renal ischaemia due to renal artery cross-clamping contributes to postoperative renal dysfunction. After reperfusion, free radicals are thought to be a significant cause of injury. Nevertheless, indisputable proof of free radical production is scarce, partly because of their transient nature. In this study, electron paramagnetic resonance and vitamin E levels were used to demonstrate the free radical production after renal ischaemia and reperfusion. Rabbit kidneys were submitted either to 15 or 60 minutes of ischaemia followed by reperfusion. A spin trap agent (alpha-phenyl-N-tert-butyl nitrone (PBN), 20mg/ml, 1 ml/min) was infused during reperfusion directly into the left renal artery via an aortic catheter before declamping. Blood samples were selectively drawn from the left renal vein for ESR analysis (Varian spectrometer E109) of lipidic residues extracted from blood samples. The vitamin E content of the left renal cortex was determined by HPLC procedure. The right renal cortex was used as a control for the vitamin E values. In the venous effluent, ESR analysis revealed the formation of a spectrum consisting of a triplet of asymmetric doublets. This signal resulted from the spin trapping by PBN of a mixture of both oxygen- and carbon- centred lipidic radicals. The amplitude of the signal which is proportional to the amount of free radicals was significantly higher after 60 minutes ischaemia than after 15 minutes.(ABSTRACT TRUNCATED AT 250 WORDS) [less ▲]

Detailed reference viewed: 67 (2 ULg)
Full Text
Peer Reviewed
See detailDirect evidence of nonadherence to antiepileptic medication in refractory focal epilepsy
CARPENTIER, Nicolas; Jonas, Jacques; Frismand, Solène et al

in Epilepsia (2013), 54(1), 20-23

Detailed reference viewed: 12 (0 ULg)