A dynamic integration algorithm to model surfaces from multiple range views

This paper presents a dynamic integration algorithm to triangulate a surface from multiple range views. This integration technique is based on the reparameterization of the canonic subsets of the Venn diagram of the set of range views. We compute a model based onN views from a model based onN–1 views by processing only the surface segments visible in theN ^th view. An experimental result shows that the proposed integration algorithm can process complex multipart objects containing holes.     

Induction plasma synthesis of fullerenes and nanotubes using carbon black–nickel particles

The existence of fullerenes (as allotropes of carbon) was established in the mid-1980s and during the last 15–18 years, systematic efforts have been devoted to improve the methods of their synthesis, including plasma-based system methods. The work presented here is focused on the investigation of fullerenes synthesis, using a radio frequency plasma reactor. The main objectives were to explore the use of induction plasma technology for the synthesis in-continuo of carbon fullerenes and to predict their formation conditions through conduct of theoretical studies. Thus, a thermodynamic study was carried out to predict the equilibrium composition of fullerenes produced at several combinations of operating conditions. Additionally, a statistical factorial design experiment, employing four factors at two levels, was also developed, in order to study the influence of the system’s operating parameters on the eventual C₆₀ fullerene yield. The results obtained showed that the reactor pressure, the electrical power and the raw material feed rates all have an important effect on the synthesis of fullerenes. The highest C₆₀ concentration in the products was found to be about 7.7 wt.%. Various other carbon nanostructures, such as nanotubes and nano-onions, were also successfully produced.     

Complications of long-term jejunostomy in children

The authors reviewed 64 jejunostomies performed in 57 patients. Data were collected regarding complications and performance of the catheters. Patient diagnoses were grouped as follows: cystic fibrosis (25), neurological impairment (14), and miscellaneous other (25). Indications were malnutrition (43), inability to feed (17), and gastroesophageal reflux (4). Complications were compared between these groups. The age range was 7 days to 23 years. There were 251 tube changes over 142 years of cumulative site patency, for an average of 1.8 tube changes per year and an average life of 2.2 +/- 2.4 years per site. The longest duration was 11.7 years. Four tube changes resulted in intraperitoneal insertion (6.2% of changes). The overall complication rate was 37.5%. The major and minor complication rates were 21.9% each. Some patients had more than one complication. Stratification of complications by diagnosis showed that the highest incidence was among the neurologically impaired children (64%), followed by those with cystic fibrosis (32%) and then others (28%). Sixty-four percent of major and 54% of minor complications occurred within the first 6 months. The mortality rate was 4.7%. Infections requiring intravenous antibiotics occurred in 9.4% of the sites, at an average site age of 8.7 +/- 7.7 months. Tube dislodgment requiring surgical replacement occurred in 9.4% of the patients. Our mortality and complication rates compare favorably to those of previously reported series. Surgical jejunostomy is a reliable long-term solution to feeding but is associated with a significant risk of complications, especially in neurologically impaired children. The risk is greatest in the first 6 months after insertion, then decreases as the site "matures."     

High-power deuterium Raman laser at 632 nm

We demonstrate a continuous-wave deuterium Raman laser that generates more than 160 mW of Stokes output power despite severe thermal effects. This output power represents nearly an order-of-magnitude increase over any previously reported continuous-wave Raman laser and is the first such system to our knowledge that uses deuterium gas as the Raman medium. The high output power is achieved through careful consideration of the electronic feedback design, frequency actuators, and pump-laser intensity noise.     

Spectral analysis of electrograms during ventricular tachycardia in a canine model: relation with epicardial isochronal maps

The purpose of this study was to assess the capability of magnitude-squared coherence and bicoherence to differentiate monomorphic ventricular tachycardia (MVT) and polymorphic ventricular tachycardia (PVT) in a canine model and to relate these results to the epicardial isochronal maps on a beat-to-beat basis. Unipolar electrograms were simultaneously recorded from the surface of both ventricles with a 127-lead sock electrode array in 12 open-chest anesthetized dogs. The sampling frequency was 500 Hz. Atrioventricular block was induced by formaldehyde injection into the atrioventricular node. The left anterior descending coronary artery was occluded for 60 minutes under ventricular pacing (140 beats/min). During reperfusion, 12 MVT episodes lasting more than 42 seconds were recorded. Left stellate ganglion stimulation induced five PVT episodes lasting more than 42 seconds. Each of these recordings was divided into seven segments of 3,072 points (6.144 seconds). After visual selection, 104 segments were extracted and classified as 73 MVT and 31 PVT segments. Magnitude-squared coherence was estimated as the cross-spectrum from two epicardial signals (on the right and left ventricles, respectively), normalized with the respective autopower spectrum. Bicoherence was estimated as the bispectrum normalized with the autopower spectrum. Magnitude-squared coherence correctly identified 96% of MVT and 81% of PVT segments for a total accuracy of 91%. Bicoherence estimated with the left ventricular lead correctly identified 100% of MVT and 77% of PVT segments with an accuracy of 93%. Beat-to-beat epicardial maps of MVT displayed a cluster of sites of origin close to the reperfusion area, while the sites of origin from beats during PVT were much more dispersed over both ventricles. A strong and significant correlation was found between the number of electrodes with the earliest epicardial activation and coherence (r = .76, P < .0001) and bicoherence (r = .68, P < .0001), respectively. A high and significant correlation was also found between both spectral estimators (r = .74, P < .0001). Coherence and bicoherence discriminated accurately between MVT and PVT. Coherence achieved better results compared with bicoherence. Coherence and bicoherence measurements showed a quantitative relation with the spatial dispersion of the sites of origin. Both spectral techniques seemed powerful enough to be used in the development of implantable devices.     

Modeling of multicomponent diffusion in high temperature flows

Three methods for computing diffusive mass transfer in non-reactive high temperature flows are compared. Results show that the widely used effective binary approximation may lead to large errors (up to 70%) in the evaluation of the mass fluxes, reflecting, therefore, on the solution of the species conservation equations. Two other approaches, the consistent effective binary diffusion due to Ramshaw, hereafter called the Ramshaw's approximation, and the linearized method are shown to reproduce accurately the mass transfer obtained with the exact formulation for multicomponent high temperature flows in isotherm conditions. When temperature gradients are imposed, the linear approximation leads to important errors (up to 40%) on the mass flux calculation.     

Attachement, contr?le parental et comportements des adolescents en relation de conseillance.

This study examined the relation between attachment and parental control experiences and the behaviours shown by adolescents in a counselling relationship. The sample was made up of 130 students and 19 counsellors participating in a counselling program offerred during the first college semester. Results showed that attachment to parents predicts some types of behaviour in counselling as a function of the quality of the attachment link. Results are discussed in reference to the attachment theory and the literature on parental control. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Early isotonic saline resuscitation from uncontrolled hemorrhage in rats

BACKGROUND: Attempts to modify traditional fluid resuscitation have been based on animal models that evaluate several variables including anesthesia. This study presents the effects of early saline resuscitation from severe uncontrolled hemorrhage unanesthetized rats. METHODS: Sixty-three female Sprague-Dawley rats were equally divided into three groups: group A, nonresuscitated; and groups B and C, resuscitated ;with isotonic saline (40 and 80 mL/kg, respectively). Hemodynamics, blood loss, survival time, and mortality were recorded for 360 minutes after the hemorrhage, which was initiated by 75% resection of the tail. RESULTS: In group C, 80 mL/kg of saline significantly lowered mortality (24% vs 76% and 71% for groups A and B, respectively) with concomitant increases in mean survival time (241 +/- 103 min vs 146 +/- 108 and 175 +/- 92 min for groups A and B, respectively). There were no statistically significant differences in blood loss, hematocrit, or hemodynamic parameters among the groups. CONCLUSIONS: Early and adequate isotonic saline resuscitation of unanesthetized rats improved outcome despite continuing hemorrhage. The significantly lower mortality rate and increased survival time were not a result of transiently improved arterial pressure and did not correlate with blood loss. No significant bleeding increases were noted in the resuscitated groups.     

Towards a general multi-view registration technique

We present an algorithm that reduces significantly the level of the registration errors between all pairs in a set of range views. This algorithm refines initial estimates of the transformation matrices obtained from either the calibrated acquisition setup or a crude manual alignment. It is an instance of a category of registration algorithms known as iterated closest-point (ICP) algorithms. The algorithm considers the network of views as a whole and minimizes the registration errors of all views simultaneously. This leads to a well-balanced network of views in which the registration errors are equally distributed, an objective not met by previously published ICP algorithms which all process the views sequentially. Experimental results show that this refinement technique improves the calibrated registrations and the quality of the integrated model for complex multi-part objects. In the case of scenes comprising man-made objects of very simple shapes, the basic algorithm faces problems common to all ICP algorithms and so must be extended