994 resultados para indirect method


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Purpose: SIOPEN scoring of 123I mIBG imaging has been shown to predict response to induction chemotherapy and outcome at diagnosis in children with HRN.Method: Patterns of skeletal 123I mIBG uptake were assigned numerical scores (Mscore) ranging from 0 (no metastasis) to 72 (diffuse metastases) within 12 body areas as described previously. 271 anonymised, paired image data sets acquired at diagnosis and on completion of Rapid COJEC induction chemotherapy were reviewed, constituting a representative sample of 1602 children treated prospectively within the HR-NBL1/SIOPEN trial. Pre-and post-treatment Mscores were compared with bone marrow cytology (BM) and 3 year event free survival (EFS).Results: Results 224/271 patients showed skeletal MIBG-uptake at diagnosis and were evaluable forMIBG-response. Complete response (CR) on MIBG to Rapid COJEC induction was achieved by 66%, 34% and 15% of patients who had pre-treatment Mscores of <18 (n¼65, 29%), 18-44 (n¼95,42%) and Y ´ 45 (n¼64, 28.5%) respectively (chi squared test p<.0001). Mscore at diagnosis and on completion of Rapid COJEC correlated strongly with BM involvement (p<0.0001). The correlation of pre score with post scores and response was highly significant (p<0.001). Most importantly, the 3 year EFS in 47 children with Mscore 0 at diagnosis was 0.68 (A ` 0.07), by comparison with 0.42 (A` 0.06), 0.35 (A` 0.05) and 0.25 (A` 0.06) for patients in pre-treatment score groups <18, 18-44 and Y ´ 45, respectively (p<0.001). AnMscore threshold ofY ´ 45 at diagnosis was associated with significantly worse outcome by comparison with all other Mscore groups (p¼0.029). The 3 year EFS of 0.53 (A` 0.07) of patients in metastatic CR (mIBG and BM) after Rapid Cojec (33%) is clearly superior to patients not achieving metastatic CR (0.24 (A ` 0.04), p¼0.005).Conclusion: SIOPEN scoring of 123I mIBG imaging has been shown to predict response to induction chemotherapy and outcome at diagnosis in children with HRN.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

With the trend in molecular epidemiology towards both genome-wide association studies and complex modelling, the need for large sample sizes to detect small effects and to allow for the estimation of many parameters within a model continues to increase. Unfortunately, most methods of association analysis have been restricted to either a family-based or a case-control design, resulting in the lack of synthesis of data from multiple studies. Transmission disequilibrium-type methods for detecting linkage disequilibrium from family data were developed as an effective way of preventing the detection of association due to population stratification. Because these methods condition on parental genotype, however, they have precluded the joint analysis of family and case-control data, although methods for case-control data may not protect against population stratification and do not allow for familial correlations. We present here an extension of a family-based association analysis method for continuous traits that will simultaneously test for, and if necessary control for, population stratification. We further extend this method to analyse binary traits (and therefore family and case-control data together) and accurately to estimate genetic effects in the population, even when using an ascertained family sample. Finally, we present the power of this binary extension for both family-only and joint family and case-control data, and demonstrate the accuracy of the association parameter and variance components in an ascertained family sample.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Nationwide, about five cents of each highway construction dollar is spent on culverts. In Iowa, average annual construction costs on the interstate, primary, and federal-aid secondary systems are about $120,000,000. Assuming the national figure applies to Iowa, about $6,000,000 are spent on culvert construction annually. For each one percent reduction in overall culvert costs, annual construction costs would be reduced by $60,000. One area of potential cost reduction lies in the sizing of the culvert. Determining the flow area and hydraulic capacity is accomplished in the initial design of the culvert. The normal design sequence is accomplished in two parts. The hydrologic portion consists of the determination of a design discharge in cubic feet per second using one of several available methods. This discharge is then used directly in the hydraulic portion of the design to determine the proper type, size, and shape of culvert to be used, based on various site and design restrictions. More refined hydrologic analyses, including rainfall-runoff analysis, flood hydrograph development, and streamflow routing techniques, are not pursued in the existing design procedure used by most county and state highway engineers.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Macroporosity is often used in the determination of soil compaction. Reduced macroporosity can lead to poor drainage, low root aeration and soil degradation. The aim of this study was to develop and test different models to estimate macro and microporosity efficiently, using multiple regression. Ten soils were selected within a large range of textures: sand (Sa) 0.07-0.84; silt 0.03-0.24; clay 0.13-0.78 kg kg-1 and subjected to three compaction levels (three bulk densities, BD). Two models with similar accuracy were selected, with a mean error of about 0.02 m³ m-3 (2 %). The model y = a + b.BD + c.Sa, named model 2, was selected for its simplicity to estimate Macro (Ma), Micro (Mi) or total porosity (TP): Ma = 0.693 - 0.465 BD + 0.212 Sa; Mi = 0.337 + 0.120 BD - 0.294 Sa; TP = 1.030 - 0.345 BD 0.082 Sa; porosity values were expressed in m³ m-3; BD in kg dm-3; and Sa in kg kg-1. The model was tested with 76 datum set of several other authors. An error of about 0.04 m³ m-3 (4 %) was observed. Simulations of variations in BD as a function of Sa are presented for Ma = 0 and Ma = 0.10 (10 %). The macroporosity equation was remodeled to obtain other compaction indexes: a) to simulate maximum bulk density (MBD) as a function of Sa (Equation 11), in agreement with literature data; b) to simulate relative bulk density (RBD) as a function of BD and Sa (Equation 13); c) another model to simulate RBD as a function of Ma and Sa (Equation 16), confirming the independence of this variable in relation to Sa for a fixed value of macroporosity and, also, proving the hypothesis of Hakansson & Lipiec that RBD = 0.87 corresponds approximately to 10 % macroporosity (Ma = 0.10 m³ m-3).

Relevância:

20.00% 20.00%

Publicador:

Resumo:

S'inscrivant dans le domaine de l'analyse des relations temporelles dans les textes, la présente étude est consacrée à la notion du futur définie en tant qu'anticipation sur les événements à venir dans le récit. Ainsi, la recherche en question se propose de mettre en lumière les différents mécanismes d'anticipation propres aux récits d'aventures au Moyen Âge. Recourant aux moyens heuristiques existants (les bases de la théorie de la réception telle qu'elle est représentée dans les travaux de Jauss, Eco et Greimas), cette thèse se concentre sur l'étude du prologue de l'oeuvre littéraire dont elle élabore une grille de lecture particulière qui tient compte de la complexité de la notion du futur envisagée aux plans grammatical (formes verbales du futur), rhétorique (la figure de la prolepse) et littéraire (les scénarios et les isotopies). La démarche de la lecture détaillée du prologue adoptée au cours de ce travail s'applique d'abord au Chevalier au Lion de Chrétien de Troyes, texte fondateur du corpus, qui constitue, pour parler avec Philippe Walter, un vrai « drame du temps ». L'étude des mécanismes d'anticipation mis en place dans le prologue se prolonge ensuite dans les chapitres consacrés à Claris et Laris et au Chevalier au Lion de Pierre Sala, deux réécritures du célèbre roman du maître champenois. Datant, respectivement, du XIIIe et du début du XVIe siècle, ces oeuvres permettent de saisir le chemin parcouru par le futur dans son aspect thématique et diachronique, ce qui est particulièrement propice au repérage des critères qui influencent l'attente du lecteur par rapport aux événements à venir au fil des siècles. Ainsi, à côté des moyens d'expression « standards » du futur (scénarios intertextuels et isotopies), la présente recherche fait apparaître d'autres facteurs qui influencent l'anticipation, notamment le procédé de la disputatio, le recours à la satire, la démarche de l'engagement indirect et l'opposition vers/prose. La seconde partie de la thèse qui traite, d'un côté, des récits consacrés à la fée Mélusine de Jean d'Arras et de Coudrette, du Livre du Cuer d'amours espris de René d'Anjou de l'autre, sert à vérifier dans quelle mesure la démarche choisie s'applique à des oeuvres du Moyen Âge tardif qui combinent des éléments empruntés à la tradition antérieure avec des éléments d'autre provenance. L'analyse de Mélusine et du Livre du Cuer conduit à ajouter deux facteurs supplémentaires qui influencent l'attente du lecteur, à savoir la démarche de l'engagement partiel et le recours au genre judiciaire. Cette étude démontre que le traitement du futur est d'un enjeu capital pour lire les textes du Moyen Âge, car il permet au lecteur, dès le prologue, de reconnaître la fin vers laquelle tend le récit et de faire par là- même une lecture enrichie, supérieure à d'autres. Telling the Future in the Middle Ages : from the Prologue to the Narrative. From Chrétien de Troyes ' Chevalier au Lion to Pierre Sala 's Chevalier au Lion. Part of the analyses of the time based relations within the texts, the present study deals with the notion of future characterized as an anticipation of the events to come in the narrative. Therefore, the purpose of this research is to bring to light the various mechanisms of anticipation peculiar to the narratives of adventures in the Middle Ages. Making the use of the existing heuristic instruments (the bases of the theory of the reception as it presents itself in the works by Jauss, Eco and Greimas), this thesis is dedicated to the study of the prologue of the work of fiction by means of a particular key for reading which takes into account the complexity of the notion of future with regard to its grammatical side (future tenses), to its rhetorical side (prolepse) and to its literary side (scenario and isotopy). First of all, the close reading of the prologue used in this work is applied to Chrétien de Troyes's Chevalier au Lion (Lion Knight), the founding text of our literary corpus, which represents, according to Philippe Walter, the real « drama of Time ». Then, the study of the mechanisms of anticipation in the prologue is carried over to the chapters devoted to Claris et Laris and to Pierre Sala's Chevalier au Lion, two romances that rewrite Chrétien de Troyes' famous work. Written, respectively, in the XIIIth and in the beginning of the XVI century, these romances enable the reader to ascertain the changes in the manner of telling the future from the thematic and diachronic point of view : this is particularly convenient to the identification of the criteria which influence the reader's expectations relative to the future events in the course of the centuries. Therefore, next to the « standard » means of expression of future (intertextual scenario and isotopy), the present study reveals other factors which influence the anticipation, in particular the method of the disputatio, the use of the satire, the approach of the indirect commitment and the verse/prose opposition. The second part of the thesis which deals with the narratives concerning the fairy Melusine written by Jean d'Arras and by Coudrette on one hand, with René d'Anjou's Livre du Cuer d'amours espris on the other hand, is used to verify to what extent the chosen approach applies to the works of fiction of the Late Middle Ages that combine the elements from the previous tradition with the elements of other origin. The analysis of Melusine's romances and of the Livre du Cuer brings us to add two new factors which influence the reader's expectations : the approach of the partial commitment, and the use of the legal discourse. This study demonstrates that the manner of telling the future is of the utmost importance to read the texts of the Middle Ages, because it enables the reader to know the end of the story from the very beginning, from the prologue, thus leading to a richer and superior reading.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Aim: Gamma Knife surgery (GKS) is a non-invasive neurosurgical stereotactic procedure, increasingly used as an alternative to open functional procedures. This includes the targeting of the ventro-intermediate (Vim) nucleus of the thalamus for tremor. We currently perform an indirect targeting, using the "quadrilatere of Guyot," as the Vim nucleus is not visible on current 3 Tesla (T) MRI acquisitions. The primary objective of the current study was to enhance anatomic imaging for Vim GKS using high-field (7 T) MRI, with the aim of refining the visualization and precision of anatomical targeting. Method: Five young healthy subjects (mean age 23 years) were scanned both on 3 and 7 T MRI in Lausanne University Hospital (CHUV) and Center for Biomedical Imaging (CIBM). Classical T1-weighted MPRAGE, T2 CISS sequences (replacing former ventriculography) and diffusion tensor imaging were acquired at 3T. We obtained high-resolution susceptibility weighted images (SWI) at 7T for the visualization of thalamic subparts. SWI was further integrated for the first time into Leksell Gamma Plan® (LGP) software and co-registered with the 3T images. A simulation of targeting of the Vim was done using the "quadrilatere of Guyot" methodology on the 3T images. Furthermore, a correlation with the position of the found target on SWI was performed. The atlas of Morel et al. was used to confirm the findings on a detailed computer analysis outside LGP. Also, 3T and 7T MRI of one patient undergoing GKS Vim thalamotomy, were obtained before and 2 years after the procedure, and studied similarly. Results: The use of SWI provided a superior resolution and improved image contrast within the central gray matter. This allowed visualization and direct delineation of groups of thalamic nuclei in vivo, including the Vim. The position of the target, as assessed with the "quadrilatere of Guyot" method on 3 T, perfectly matched with the supposed one of the Vim on the SWI. Furthermore, a 3-dimensional model of the Vim target area was created on the basis of 3T and 7T images. Conclusion: This is the first report of the integration of SWI high-field MRI into the LGP in healthy subjects and in one patient treated GKS Vim thalamotomy. This approach aims at the improvement of targeting validation and further direct targeting of the Vim in tremor. The anatomical correlation between the direct visualization on 7T and the current targeting methods on 3T seems to show a very good anatomical matching.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A HPLC method is presented for the identification and quantification in plasma and urine of beta-adrenergic receptor antagonists (betaxolol, carteolol, metipranolol, and timolol) commonly prescribed in ophthalmology. An extraction method is described using pindolol as an internal standard. An RSIL 10 micron column was used. The lower detection limits of the beta-blockers were found to be 4-27 ng/ml. This method is simple, rapid and sensitive; moreover, it allows the determination of 8 other beta-blockers.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A modified Bargmann-Wigner method is used to derive (6s + 1)-component wave equations. The relation between different forms of these equations is shown.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

OBJECTIVE: To describe a method to obtain a profile of the duration and intensity (speed) of walking periods over 24 hours in women under free-living conditions. DESIGN: A new method based on accelerometry was designed for analyzing walking activity. In order to take into account inter-individual variability of acceleration, an individual calibration process was used. Different experiments were performed to highlight the variability of acceleration vs walking speed relationship, to analyze the speed prediction accuracy of the method, and to test the assessment of walking distance and duration over 24-h. SUBJECTS: Twenty-eight women were studied (mean+/-s.d.) age: 39.3+/-8.9 y; body mass: 79.7+/-11.1 kg; body height: 162.9+/-5.4 cm; and body mass index (BMI) 30.0+/-3.8 kg/m(2). RESULTS: Accelerometer output was significantly correlated with speed during treadmill walking (r=0.95, P<0.01), and short unconstrained walks (r=0.86, P<0.01), although with a large inter-individual variation of the regression parameters. By using individual calibration, it was possible to predict walking speed on a standard urban circuit (predicted vs measured r=0.93, P<0.01, s.e.e.=0.51 km/h). In the free-living experiment, women spent on average 79.9+/-36.0 (range: 31.7-168.2) min/day in displacement activities, from which discontinuous short walking activities represented about 2/3 and continuous ones 1/3. Total walking distance averaged 2.1+/-1.2 (range: 0.4-4.7) km/day. It was performed at an average speed of 5.0+/-0.5 (range: 4.1-6.0) km/h. CONCLUSION: An accelerometer measuring the anteroposterior acceleration of the body can estimate walking speed together with the pattern, intensity and duration of daily walking activity.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In forensic science, there is a strong interest in determining the post-mortem interval (PMI) of human skeletal remains up to 50 years after death. Currently, there are no reliable methods to resolve PMI, the determination of which relies almost exclusively on the experience of the investigating expert. Here we measured (90)Sr and (210)Pb ((210)Po) incorporated into bones through a biogenic process as indicators of the time elapsed since death. We hypothesised that the activity of radionuclides incorporated into trabecular bone will more accurately match the activity in the environment and the food chain at the time of death than the activity in cortical bone because of a higher remodelling rate. We found that determining (90)Sr can yield reliable PMI estimates as long as a calibration curve exists for (90)Sr covering the studied area and the last 50 years. We also found that adding the activity of (210)Po, a proxy for naturally occurring (210)Pb incorporated through ingestion, to the (90)Sr dating increases the reliability of the PMI value. Our results also show that trabecular bone is subject to both (90)Sr and (210)Po diagenesis. Accordingly, we used a solubility profile method to determine the biogenic radionuclide only, and we are proposing a new method of bone decontamination to be used prior to (90)Sr and (210)Pb dating.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The rate of carbon dioxide production is commonly used as a measure of microbial activity in the soil. The traditional method of CO2 determination involves trapping CO2 in an alkali solution and then determining CO2 concentration indirectly by titration of the remaining alkali in the solution. This method is still commonly employed in laboratories throughout the world due to its relative simplicity and the fact that it does not require expensive, specific equipment. However, there are several drawbacks: the method is time-consuming, requires large amounts of chemicals and the consistency of results depends on the operator's skills. With this in mind, an improved method was developed to analyze CO2 captured in alkali traps, which is cheap and relatively simple, with a substantially shorter sample handling time and reproducibility equivalent to the traditional titration method. A comparison of the concentration values determined by gas phase flow injection analysis (GPFIA) and titration showed no significant difference (p > 0.05), but GPFIA has the advantage that only a tenth of the sample volume of the titration method is required. The GPFIA system does not require the purchase of new, costly equipment but the device was constructed from items commonly found in laboratories, with suggestions for alternative configurations for other detection units. Furthermore, GPFIA for CO2 analysis can be equally applied to samples obtained from either the headspace of microcosms or from a sampling chamber that allows CO2 to be released from alkali trapping solutions. The optimised GPFIA method was applied to analyse CO2 released from degrading hydrocarbons from a site contaminated by diesel spillage.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A large variety of techniques have been used to measure soil CO2 released from the soil surface, and much of the variability observed between locations must be attributed to the different methods used by the investigators. Therefore, a minimum protocol of measurement procedures should be established. The objectives of this study were (a) to compare different absorption areas, concentrations and volumes of the alkali trapping solution used in closed static chambers (CSC), and (b) to compare both, the optimized alkali trapping solution and the soda-lime trapping using CSC to measure soil respiration in sugarcane areas. Three CO2 absorption areas were evaluated (7; 15 and 20 % of the soil emission area or chamber); two volumes of NaOH (40 and 80 mL) at three concentrations (0.1, 0.25 and 0.5 mol L-1). Three different types of alkaline traps were tested: (a), 80 mL of 0.5 mol L-1 NaOH in glass containers, absorption area 15 % (V0.5); (b) 40 mL of 2 mol L-1 NaOH retained in a sponge, absorption area 80 % (S2) and (c) 40 g soda lime, absorption area 15 % (SL). NaOH concentrations of 0.5 mol L-1 or lower underestimated the soil CO2-C flux or CO2 flux. The lower limit of the alkali trap absorption area should be a minimum of 20 % of the area covered by the chamber. The 2 mol L-1 NaOH solution trap (S2) was the most efficient (highest accuracy and highest CO2 fluxes) in measuring soil respiration.