1,880 research outputs found
ORIGINAL PC PROGRAM FOR DETERMINATION OF THE DIALYSIS DOSE AND NUTRITIONAL STATUS OF PATIENTS ON CHRONIC HAEMODIALYSIS
An original PC program created in the Centre for Haemodialysis, Clinic of Nephrology, Haemodialysis and Toxicology, Medical University of Varna, and designed for determination of the dialysis dose and nutritional status of patients on periodic haemodialysis (PHD) was presented. The study covered 58 patients on PHD, 24 females and 34 males monitored at 3-month intervals for one year. Using a PC software and this program the following parameters were estimated: single pool model - KT/Vsp, urea reduction rate (URR), and nutrition status (nPCR). The mean KT/Vsp value (single pool) of 1,13 ± 0,14 was close to that recommended by the Dialysis Outcomes Quality Initiative of the National Kidney Foundation. However, a further optimization of dialysis procedures was required. The mean value of protein intake in these patients during the period of observation was of 1,04 ± 0,13 g/kg/d. It should be emphasized that despite the acceptable mean nPCR value the protein intake remained insufficient in 49 per cent of the cases. There was a positive correlation between KT/V and PCR (r = 0,63; p < 0,05). There was no statistically significant difference between the parameters' values from the urea-kinetic modelling (UKM) and those calculated using authors' PC program that testified to the reliability of the results. This program allowed the prognostication of the necessary dialysis dose by rendering an account of the individual patient's parameters and the ultrafdtration required and then by choosing the optimal values of dialysis duration and blood flow
Scaling properties of step bunches induced by sublimation and related mechanisms: A unified perspective
This work provides a ground for a quantitative interpretation of experiments
on step bunching during sublimation of crystals with a pronounced
Ehrlich-Schwoebel (ES) barrier in the regime of weak desorption. A strong step
bunching instability takes place when the kinetic length is larger than the
average distance between the steps on the vicinal surface. In the opposite
limit the instability is weak and step bunching can occur only when the
magnitude of step-step repulsion is small. The central result are power law
relations of the between the width, the height, and the minimum interstep
distance of a bunch. These relations are obtained from a continuum evolution
equation for the surface profile, which is derived from the discrete step
dynamical equations for. The analysis of the continuum equation reveals the
existence of two types of stationary bunch profiles with different scaling
properties. Through a mathematical equivalence on the level of the discrete
step equations as well as on the continuum level, our results carry over to the
problems of step bunching induced by growth with a strong inverse ES effect,
and by electromigration in the attachment/detachment limited regime. Thus our
work provides support for the existence of universality classes of step
bunching instabilities [A. Pimpinelli et al., Phys. Rev. Lett. 88, 206103
(2002)], but some aspects of the universality scenario need to be revised.Comment: 21 pages, 8 figure
A Class of Collisions of Plane Impulsive Light--Like Signals in General Relativity
We present a systematic study of collisions of homogeneous, plane--fronted,
impulsive light--like signals which do not interact after head--on collision.
For the head--on collision of two such signals, six real parameters are
involved, three from each of the incoming signals. We find two necessary
conditions to be satisfied by these six parameters for the signals to be
non--interacting after collision. We then solve the collision problem in
general when these necessary conditions hold. After collision the two signals
focus each other at Weyl curvature singularities on each others signal front.
Our family of solutions contains some known collision solutions as special
cases.Comment: 14 pages, late
Scaling Up Sustainability From an Operational Capability to a Dynamic Capability:The Case of Royal Bank of Scotland
Synthetic and Real Inputs for Tool Segmentation in Robotic Surgery
Semantic tool segmentation in surgical videos is important for surgical scene understanding and computer-assisted interventions as well as for the development of robotic automation. The problem is challenging because different illumination conditions, bleeding, smoke and occlusions can reduce algorithm robustness. At present labelled data for training deep learning models is still lacking for semantic surgical instrument segmentation and in this paper we show that it may be possible to use robot kinematic data coupled with laparoscopic images to alleviate the labelling problem. We propose a new deep learning based model for parallel processing of both laparoscopic and simulation images for robust segmentation of surgical tools. Due to the lack of laparoscopic frames annotated with both segmentation ground truth and kinematic information a new custom dataset was generated using the da Vinci Research Kit (dVRK) and is made available
Analytical modeling of micelle growth. 2. Molecular thermodynamics of mixed aggregates and scission energy in wormlike micelles
Hypotheses: Quantitative molecular-thermodynamic theory of the growth of
giant wormlike micelles in mixed nonionic surfactant solutions can be developed
on the basis of a generalized model, which includes the classical phase
separation and mass action models as special cases. The generalized model
describes spherocylindrical micelles, which are simultaneously multicomponent
and polydisperse in size. Theory: The model is based on explicit analytical
expressions for the four components of the free energy of mixed nonionic
micelles: interfacial-tension, headgroup-steric, chain-conformation components
and free energy of mixing. The radii of the cylindrical part and the spherical
endcaps, as well as the chemical composition of the endcaps, are determined by
minimization of the free energy. Findings: In the case of multicomponent
micelles, an additional term appears in the expression for the micelle growth
parameter (scission free energy), which takes into account the fact that the
micelle endcaps and cylindrical part have different compositions. The model
accurately predicts the mean mass aggregation number of wormlike micelles in
mixed nonionic surfactant solutions without using any adjustable parameters.
The endcaps are enriched in the surfactant with smaller packing parameter that
is better accommodated in regions of higher mean surface curvature. The model
can be further extended to mixed solutions of nonionic, ionic and zwitterionic
surfactants used in personal-care and house-hold detergency
Widening siamese architectures for stereo matching
Computational stereo is one of the classical problems in computer vision. Numerous algorithms and solutions have been reported in recent years focusing on developing methods for computing similarity, aggregating it to obtain spatial support and finally optimizing an energy function to find the final disparity. In this paper, we focus on the feature extraction component of stereo matching architecture and we show standard CNNs operation can be used to improve the quality of the features used to find point correspondences. Furthermore, we use a simple space aggregation that hugely simplifies the correlation learning problem, allowing us to better evaluate the quality of the features extracted. Our results on benchmark data are compelling and show promising potential even without refining the solution
Photometric and spectroscopic variability of the FUor star V582 Aurigae
We carried out BVRI CCD photometric observations in the field of V582 Aur
from 2009 August to 2013 February. We acquired high-, medium-, and
low-resolution spectroscopy of V582 Aur during this period. To study the
pre-outburst variability of the target and construct its historical light
curve, we searched for archival observations in photographic plate collections.
Both CCD and photographic observations were analyzed using a sequence of 14
stars in the field of V582 Aur calibrated in BVRI. The pre-outburst
photographic observations of V582 Aur show low-amplitude light variations
typical of T Tauri stars. Archival photographic observations indicate that the
increase in brightness began in late 1984 or early 1985 and the star reached
the maximum level of brightness at 1986 January. The spectral type of V582 Aur
can be defined as G0I with strong P Cyg profiles of H alpha and Na I D lines,
which are typical of FU Orionis objects. Our BVRI photometric observations show
large amplitude variations V~2.8 mag. during the 3.5 year period of
observations. Most of the time, however, the star remains in a state close to
the maximum brightness. The deepest drop in brightness was observed in the
spring of 2012, when the brightness of the star fell to a level close to the
pre-outburst. The multicolor photometric data show a color reversal during the
minimum in brightness, which is typical of UX Ori variables. The corresponding
spectral observations show strong variability in the profiles and intensities
of the spectral lines (especially H alpha), which indicate significant changes
in the accretion rate. On the basis of photometric monitoring performed over
the past three years, the spectral properties of the maximal light, and the
shape of the long-term light curve, we confirm the affiliation of V582 Aur to
the group of FU Orionis objects.Comment: 9 pages, 8 figures, accepted for publication in A&
H-alpha observations of the gamma-ray-emitting Be/X-ray binary LSI+61303: orbital modulation, disk truncation, and long-term variability
We report 138 spectral observations of the H-alpha emission line of the
radio- and gamma-ray-emitting Be/X-ray binary LSI+61303 obtained during the
period of September 1998 -- January 2013. From measuring various H-alpha
parameters, we found that the orbital modulation of the H-alpha is best visible
in the equivalent width ratio EW(B)/EW(R), the equivalent width of the blue
hump, and in the radial velocity of the central dip. The periodogram analysis
confirmed that the H-alpha emission is modulated with the orbital and
superorbital periods. For the past 20 years the radius of the circumstellar
disk is similar to the Roche lobe size at the periastron. It is probably
truncated by a 6:1 resonance. The orbital maximum of the equivalent width of
H-alpha emission peaks after the periastron and coincides on average with the
X-ray and gamma-ray maxima. All the spectra are available upon request from the
authors and through the CDS.Comment: 11 pages, accepted for publication in A&
Vision-based and marker-less surgical tool detection and tracking: a review of the literature
In recent years, tremendous progress has been made in surgical practice for example with Minimally Invasive Surgery (MIS). To overcome challenges coming from deported eye-to-hand manipulation, robotic and computer-assisted systems have been developed. Having real-time knowledge of the pose of surgical tools with respect to the surgical camera and underlying anatomy is a key ingredient for such systems. In this paper, we present a review of the literature dealing with vision-based and marker-less surgical tool detection. This paper includes three primary contributions: (1) identification and analysis of data-sets used for developing and testing detection algorithms, (2) in-depth comparison of surgical tool detection methods from the feature extraction process to the model learning strategy and highlight existing shortcomings, and (3) analysis of validation techniques employed to obtain detection performance results and establish comparison between surgical tool detectors. The papers included in the review were selected through PubMed and Google Scholar searches using the keywords: âsurgical tool detectionâ, âsurgical tool trackingâ, âsurgical instrument detectionâ and âsurgical instrument trackingâ limiting results to the year range 2000 2015. Our study shows that despite significant progress over the years, the lack of established surgical tool data-sets, and reference format for performance assessment and method ranking is preventing faster improvement
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