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Target Value (target + value)

Distribution by Scientific Domains

Medical Sciences	35%
Engineering	17%
Chemistry	17%

Selected Abstracts

Flow in Lymphatic Networks: Interaction between Hepatic and Intestinal Lymph Vessels

MICROCIRCULATION, Issue 4 2001
RANDOLPH H. STEWART
ABSTRACT Objective: Lymph from both the liver and intestine flows into the cisterna chyli. We hypothesized that increasing liver lymph flow would increase cisterna chyli pressure and, thereby, decrease intestinal lymph flow, potentiating intestinal edema formation. Methods: Anesthetized dogs were instrumented to measure and manipulate portal vein pressure and cisterna chyli pressure. The effects of directly increasing portal pressure with and without directly increasing cisterna chyli pressure on intestinal wet-to-dry ratio and intestinal ascites formation rate were determined. Target values for portal and cisterna chyli pressures were determined following elevation of inferior vena caval pressure to levels seen in patients with obstructive caval disease. Results: Direct elevation of portal pressure (Pport) alone to 17.5 mm Hg caused a significant increase in intestinal wet-to-dry ratio (3.98 ± 0.24 vs. 3.40 ± 0.43) and the rate of ascites formation (0.36 ± 0.12 vs. 0.05 ± 0.03 mL/g dry wt/h). Simultaneous direct elevation of cisterna chyli pressure to 6.0 mm Hg and Pport to 17.5 mm Hg caused further increases in intestinal wet-to-dry ratio (5.52 ± 1.20) and ascites formation (0.57 ± 0.11 mL/g dry wt./h). Conclusions: Inferior vena caval hypertension increases liver lymph flow that elevates cisterna chyli pressure, which inhibits intestinal lymph flow and augments intestinal edema formation. [source]

Use of biological reference points for the conservation of Atlantic salmon, Salmo salar, in the River Lune, North West England

FISHERIES MANAGEMENT & ECOLOGY, Issue 1 2006
M. W. APRAHAMIAN
Abstract, The development and use of biological reference points (BRPs) for salmon, Salmo salar L., conservation on the River Lune, England were examined. The Lune supports recreational and net fisheries with annual catches averaging 1332 and 2146 salmon, respectively. Using models transported from other river systems, BRPs were developed that were exclusive to the Lune; specifically the number of eggs deposited and carrying capacity estimates for age 0+ and 1+ parr. The conservation limit was estimated at 11.9 million eggs, and to ensure that the conservation limit was exceeded 80% of the time, the management target was set at 14.4 million eggs (equivalent to ,5000 adults). Between 1989 and 1998 the management target was exceeded in only 2 years. Comparison of juvenile salmon densities in 1991 and 1997 with estimates of carrying capacity indicated that 0+ and 1+ parr densities were at around 60% of carrying capacity and may relate to the number of eggs deposited in 1990 and 1996 being approximately 70% of the target value. From, and including, the 2000 fishing season, regulations to ensure that the conservation limit is met 4 years out of 5 were introduced. These consisted of a reduction from 26 to 12 haaf nets, from 10 to seven drift nets and a four-fish bag limit for the rod fishery. In the period between 2000 and 2004 there was a marked increase in the estimated number of salmon spawning and the management target value of ,5000 spawning adults was exceeded in all years. There was also an increase in the juvenile salmon population. The estimated level of exploitation in the net and rod fisheries reduced from 29.9% to 13.8% and from 26.4% to 14.8% respectively, after the introduction of the regulations. [source]

Volume targeted ventilation (volume guarantee) in the weaning phase of premature newborn infants

PEDIATRIC PULMONOLOGY, Issue 10 2007
F. Scopesi MD
Abstract Objective Several options are currently available in neonatal mechanical ventilation: complete breathing synchronization (patient triggered ventilation, synchronized intermittent positive pressure ventilation,SIPPV); positive pressure flow-cycled ventilation (pressure support ventilation, PSV); and volume targeted positive pressure ventilation (volume guarantee, VG). The software algorithm for the guarantee volume attempts to deliver a tidal volume (Vt) as close as possible to what has been selected by the clinician as the target volume. Main objectives of the present study were to compare patient,ventilator interactions and Vt variability in premature infants recovering from respiratory distress syndrome (RDS) who were weaned by various ventilator modes (SIMV/PSV,+,VG/SIPPV,+,VG and SIMV,+,VG). Methods This was a short-term crossover trial in which each infant served as his/her own control. Ten premature infants born before the 32nd week of gestation in the recovery phase of RDS were enrolled in the study. All recruited infants started ventilation with SIPPV and in the weaning phase were switched to synchronized intermittent mandatory ventilation (SIMV). Baseline data were collected during an initial 20-min period of monitoring with the infant receiving SIMV alone, then they were switched to SIPPV,+,VG for a 20-min period and then switched back to SIMV for 15 min. Next, they were switched to PSV,+,VG for the study period and switched back to SIMV for a further 15 min. Finally, they were switched to SIMV,+,VG and, at the end of monitoring, they were again switched back to SIMV alone. Results Each mode combined with VG discharged comparable Vts, which were very close to the target volume. Among the VG-combined modes, mean variability of Vt from preset Vt was significantly different. Variability from the target value was significantly lower in SIPPV and PSV modes than in SIMV (P,<,0.0001 and P,<,0.04 respectively). SIPPV,+,VG showed greater stability of Vt, fewer large breaths, lower respiratory rate, and allowed for lower peak inspiratory pressure than what was delivered by the ventilator during other modes. No significant changes in blood gases were observed after each of the study periods. Conclusions With regards to the weaning phase, among combined modes, both of the ones in which every breath is supported (SIPPV/PSV) are likely to be the most effective in the delivery of stable Vt using a low working pressure, thus, at least in the short term, likely more gentle for the neonatal lung. In summary, we can suggest that the VG option, when combined with traditional, patient triggered ventilation, adheres very closely to the proposed theoretical algorithm, achieving highly effective ventilation. Pediatr Pulmonol. 2007; 42:864,870. © 2007 Wiley-Liss, Inc. [source]

Distributional properties of estimated capability indices based on subsamples

QUALITY AND RELIABILITY ENGINEERING INTERNATIONAL, Issue 2 2003
Kerstin Vännman
Abstract Under the assumption of normality, the distribution of estimators of a class of capability indices, containing the indices , , and , is derived when the process parameters are estimated from subsamples. The process mean is estimated using the grand average and the process variance is estimated using the pooled variance from subsamples collected over time for an in-control process. The derived theory is then applied to study the use of hypothesis testing to assess process capability. Numerical investigations are made to explore the effect of the size and number of subsamples on the efficiency of the hypothesis test for some indices in the studied class. The results for and indicate that, even when the total number of sampled observations remains constant, the power of the test decreases as the subsample size decreases. It is shown how the power of the test is dependent not only on the subsample size and the number of subsamples, but also on the relative location of the process mean from the target value. As part of this investigation, a simple form of the cumulative distribution function for the non-central -distribution is also provided. Copyright © 2003 John Wiley & Sons, Ltd. [source]

The total median in statistical quality control

APPLIED STOCHASTIC MODELS IN BUSINESS AND INDUSTRY, Issue 4 2004
Fernanda Figueiredo
Abstract In industry, most of the process observations are assumed to come from a normal population, but usually we merely want to control the process mean value. It is thus sensible to find control statistics, which are ,robust' to monitor the process mean, giving the expected rate of false alarms whenever that mean is close to the target value, although not under a normal regime. Simulation studies for a few symmetric and asymmetric distributions allow us to suggest the total median as a robust median estimator. We shall here analyse such a robustness, as well as the robustness of the total median chart comparatively to the sample mean chart, whenever we want to control the mean value of a symmetric underlying parent. Some indication is also provided on the comparative out-of-control behaviour of the two charts. Copyright © 2004 John Wiley & Sons, Ltd. [source]

Liquid chromatographic method for the determination of sirolimus in blood using electrochemical detection

BIOMEDICAL CHROMATOGRAPHY, Issue 3 2009
Nobuo Mochizuki
Abstract Therapeutic drug monitoring of sirolimus (rapamycin) is important for immunosuppressive therapy in solid organ transplantation. We have developed a simple and reliable method for determining blood concentrations of sirolimus using reversed-phase HPLC with electrochemical detection (ECD). The E2 potential was set at +900 mV. The potential of guard cell was set at +950 mV and that of the E1 cell at +400 mV. The method was linear for a concentration range of 1,50 ng/mL when 0.5 mL blood was used. The correlation coefficients of all standard curves were greater than or equal to 0.999. The limit of detection was 0.5 ng/mL. The inter-assay precision ranged from 3.22 to 7.48%, and the coefficient of variation (CV) for a quality control sample at 10 ng/mL was 7.48% with a bias of 8.4% from the target value. The intra-assay precision ranged from 0.72 to 3.71%, and the CV for a quality control sample at 10 ng/mL was 0.72% with a bias of 6.8% from the target value. In a solid organ transplant recipient, trough concentrations of sirolimus were well within the analytic range of the HPLC/ECD procedure. The method described here is suitable for management of sirolimus therapy in solid organ transplantation. Copyright © 2008 John Wiley & Sons, Ltd. [source]

Apnea testing for the diagnosis of brain death

ACTA NEUROLOGICA SCANDINAVICA, Issue 6 2005
C. J. G. Lang
Objectives,,, A review is given on various methods, preconditions and pitfalls of apnea testing for the diagnosis of brain death. Materials and methods,,, An extensive medical data base search was implemented by information gathered from books and our own experience with more than 2000 apnea tests. Results,,, While testing for apnea (AT) is considered indispensable worldwide, recommendations and handling differ. Rather than relying on elapsed time, a specific target value for the partial arterial pressure of carbon dioxide (PaCO2) should be aimed at being the maximum physiological stimulus for respiration. Methodological points are elaborated upon in detail for apneic oxygenation and hypoventilation. Conclusion,,, AT is an indispensable element of diagnosing brain death. Although with proper handling and adequate precautions AT is safe, it should be performed as a last resort. An international agreement on target values for the PaCO2 is desirable. [source]

Effect of Operating Parameters on the Condensation of Ammonium Sulfate by Electrodialysis

CHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 9 2008
H. Yang
Abstract The separation of ammonium sulfate from dilute solution by electrodialysis was investigated. From the results obtained, it is suggested that it is feasible to separate ammonium sulfate from aqueous solution by electrodialysis. The removal performance of ammonium sulfate obtained was very satisfactory. The optimal cation and anion membranes were found. The removal efficiencies were influenced by voltage, initial concentration, flow rate and temperature. High voltage and high temperature are beneficial to this separation process, but high fluid flow rate and concentrated initial concentration prolong the operation time required to achieve the target value. It was found that the optimal outlet concentration is 1,g/L, since the operation time is prolonged almost two-fold if the outlet concentration is decreased from 1,g/L to 0.5,g/L. [source]

Concurrent Viewing of Multiple Attribute-Specific Subspaces

COMPUTER GRAPHICS FORUM, Issue 3 2008
Robert Sisneros
Abstract In this work we present a point classification algorithm for multi-variate data. Our method is based on the concept of attribute subspaces, which are derived from a set of user specified attribute target values. Our classification approach enables users to visually distinguish regions of saliency through concurrent viewing of these subspaces in single images. We also allow a user to threshold the data according to a specified distance from attribute target values. Based on the degree of thresholding, the remaining data points are assigned radii of influence that are used for the final coloring. This limits the view to only those points that are most relevant, while maintaining a similar visual context. [source]

Behavior of moment-resisting frame structures subjected to near-fault ground motions

EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 6 2004
Babak Alavi
Abstract Near-fault ground motions impose large demands on structures compared to ,ordinary' ground motions. Recordings suggest that near-fault ground motions with ,forward' directivity are characterized by a large pulse, which is mostly orientated perpendicular to the fault. This study is intended to provide quantitative knowledge on important response characteristics of elastic and inelastic frame structures subjected to near-fault ground motions. Generic frame models are used to represent MDOF structures. Near-fault ground motions are represented by equivalent pulses, which have a comparable effect on structural response, but whose characteristics are defined by a small number of parameters. The results demonstrate that structures with a period longer than the pulse period respond very differently from structures with a shorter period. For the former, early yielding occurs in higher stories but the high ductility demands migrate to the bottom stories as the ground motion becomes more severe. For the latter, the maximum demand always occurs in the bottom stories. Preliminary regression equations are proposed that relate the parameters of the equivalent pulse to magnitude and distance. The equivalent pulse concept is used to estimate the base shear strength required to limit story ductility demands to specific target values. Copyright © 2004 John Wiley & Sons, Ltd. [source]

Diagnostic accuracy of digital photography and image analysis for the measurement of foot conformation in the horse

EQUINE VETERINARY JOURNAL, Issue 7 2008
J. M. WHITE
Summary Reasons for performing study: Rigorous evaluation of practicable methods for the objective assessment of foot conformation has not been performed. Objectives: To assess the practicability, precision and accuracy of the process of obtaining measurements of horses' feet using photography and image processing software. Methods: Precision study: Lateral photographs of horses' feet were obtained twice by 2 veterinary surgeons (image acquisition - IAc). Photographs were analysed by 2 masked veterinary surgeons on 2 occasions (image analysis - IAn). Measurements were compared within and between operators for self and non-self acquired photographs. Agreement indices (AIs) and 95% limits of agreement (LOA) were calculated for the IAn process alone and for the combined IAc + IAn processes. Accuracy study: Measurements obtained from lateral photographs were compared with those obtained from lateromedial radiographs. AIs and 95% LOA were calculated for each measurement. Results: Precision study: Mean intra- and interoperator AIs for the IAn process alone were ,0.90 while those for the combined IAc + IAn processes were ,0.89 for all measurements. Similar mean AIs and 95% LOA were calculated regardless of image origin. The 95% LOA for hoof angle, heel height/toe height% and coronary band angle for all comparisons were within target values. Accuracy study: Mean AIs were ,0.89 for all measurements. The 95% LOA for heel height/toe height% and coronary band angle were within target values. Conclusions: Excellent precision was identified within and between operators regardless of image origin. High levels of accuracy were also identified, especially for heel height/toe height% and coronary band angle, indicating that photography and radiography may be used interchangeably. Potential relevance: Acquisition and analysis of photographic images is an appropriate method for the objective measurement of foot conformation, both in clinical and research settings. [source]

Groundwater parameter estimation via the unsteady adjoint variable formulation of discrete sensitivity analysis

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 6 2002
C. O. E. Burg
Abstract Discrete sensitivity analysis (DSA) is a method that efficiently estimates the derivatives of a numerically approximated objective function with respect to a set of parameters at a fraction of the cost of using finite differences. Coupled with an optimization algorithm, this method can be used to locate the optimal set of parameters for the objective function. The time dependent adjoint variable formulation of discrete sensitivity analysis is derived and applied to a time-dependent, two-dimensional groundwater code. The derivatives agreed with finite difference derivatives to between 6 and 8 significant digits, at approximately , the computational cost. Using the BFGS optimization algorithm to update the parameters, the parameter estimation technique successfully identified the target values, for problems with small number of parameters. Copyright © 2002 John Wiley & Sons, Ltd. [source]

Light as a Controlling Tool

LASER TECHNIK JOURNAL, Issue 1 2010
White Light Interferometry in Quality Assurance of Photovoltaic Samples
The photovoltaic industry is characterized by a permanent, substantial growing during the last years. Today improving efficiencies and reduction of manufacturing cost of solar cells is essential for the success in the competitive market. The reduction of manufacturing costs is associated with high volume manufacturing of the solar cells by perpetuation of high quality standards and requirements for small tolerances. Measurements of the topography of solar cells now start to play an important role in the quality assurance of the manufacturing process. It allows the three-dimensional mapping of a complete area with subsequent parameter extraction: so the efficiency of a solar cell depends on the wafer structure: Perfect smooth surfaces absorb less photons than surfaces with a certain, optimized roughness, whereas protecting layers should be as smooth and flat as possible. Similar to all Microsystems the structures can be investigated and compared to the target values: examples are layer thickness, widths and depths of structured lines, the volume-determination of hollows, defects, pores or abrasion/deposition rates. It also encompasses the 3D profile of printed circuit board tracks or special structures for sophisticated high efficiency photovoltaic elements. [source]

A practice survey on vasopressor and inotropic drug therapy in Scandinavian intensive care units

ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 6 2003
A. Oldner
Background: This practice survey was performed to analyse the indications for use of vasopressor/inotropic drugs, preferred drugs and doses as well as concomitant monitoring and desired haemodynamic target values in Scandinavian ICUs. An internet-based reporting system was implemented. Methods: A total of 223 ICUs were identified in the Scandinavian countries and invited to participate in a one-day point-prevalence study. An internet-based database was constructed and a practice survey protocol designed to identify haemodynamic monitoring, indications for vasopressor/inotropic drug-therapy, fluids used for volume loading, pretreatment circulatory state, actual and targeted haemodynamic variables. Patients were eligible for the study if on vasopressor/inotropic drug-therapy for more than 4 h. Results: A total of 114 ICUs participated. A total of 114 adult patients matched the inclusion criteria. Sixty-seven per cent of the patients had received vasopressor/inotropic drug-treatment for >24 h and 32% received more than one drug. Arterial hypotension (92%) and oliguria (50%) were most common indications. Fluid loading prior to therapy was reported in 87% of patients. Dopamine (47%) and noradrenaline (44%) were the most commonly used drugs followed by dobutamine (24%). No other drug exceeded 6%. Non-catecholamine drugs were rarely used even in cardiac failure patients. Invasive arterial pressure was monitored in 95% of patients, pulmonary artery catheters were used in 19%. Other cardiac output monitoring techniques were used in 8.5% of the patients. Conclusion: Dopamine and noradrenaline seem to be the most commonly used inotropic/vasopressor drugs in Scandinavia. Traditional indications for inotropic/vasopressor support as hypotension and oliguria seem to be most common. Invasive monitoring was used in almost all patients, whereas a limited use of pulmonary artery catheters was noted. The internet-based reporting system proved to be an efficient tool for data collection. [source]

Preparation of starch and soluble sugars of plant material for the analysis of carbon isotope composition: a comparison of methods,

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 16 2009
Andreas Richter
Starch and soluble sugars are the major photosynthetic products, and their carbon isotope signatures reflect external versus internal limitations of CO2 fixation. There has been recent renewed interest in the isotope composition of carbohydrates, mainly for use in CO2 flux partitioning studies at the ecosystem level. The major obstacle to the use of carbohydrates in such studies has been the lack of an acknowledged method to isolate starch and soluble sugars for isotopic measurements. We here report on the comparison and evaluation of existing methods (acid and enzymatic hydrolysis for starch; ion-exchange purification and compound-specific analysis for sugars). The selectivity and reproducibility of the methods were tested using three approaches: (i) an artificial leaf composed of a mixture of isotopically defined compounds, (ii) a C4 leaf spiked with C3 starch, and (iii) two natural plant samples (root, leaf). Starch preparation methods based on enzymatic or acid hydrolysis did not yield similar results and exhibited contaminations by non-starch compounds. The specificity of the acidic hydrolysis method was especially low, and we therefore suggest terming these preparations as HCl-hydrolysable carbon, rather than starch. Despite being more specific, enzyme-based methods to isolate starch also need to be further optimized to increase specificity. The analysis of sugars by ion-exchange methods (bulk preparations) was fast but produced more variable isotope compositions than compound-specific methods. Compound-specific approaches did not in all cases correctly reproduce the target values, mainly due to unsatisfactory separation of sugars and background contamination. Our study demonstrates that, despite their wide application, methods for the preparation of starch and soluble sugars for the analysis of carbon isotope composition are not (yet) reliable enough to be routinely applied and further research is urgently needed to resolve the identified problems. Copyright © 2009 John Wiley & Sons, Ltd. [source]