Use of exhaled nitric oxide measurements to guide treatment in chronic asthma.
BACKGROUND International guidelines for the treatment of asthma recommend adjusting the dose of inhaled corticosteroids on the basis of symptoms, bronchodilator requirements, and the results of pulmonary-function tests. Measurements of the fraction of exhaled nitric oxide (FE(NO)) constitute a noninvasive marker that may be a useful alternative for the adjustment of inhaled-corticosteroid treatment. METHODS In a single-blind, placebo-controlled trial, we randomly assigned 97 patients with asthma who had been regularly receiving treatment with inhaled corticosteroids to have their corticosteroid dose adjusted, in a stepwise fashion, on the basis of either FE(NO) measurements or an algorithm based on conventional guidelines. After the optimal dose was determined (phase 1), patients were followed up for 12 months (phase 2). The primary outcome was the frequency of exacerbations of asthma; the secondary outcome was the mean daily dose of inhaled corticosteroid. RESULTS Forty-six patients in the FE(NO) group and 48 in the group whose asthma was treated according to conventional guidelines (the control group) completed the study. The final mean daily doses of fluticasone, the inhaled corticosteroid that was used, were 370 microg per day for the FE(NO) group (95 percent confidence interval, 263 to 477) and 641 microg per day for the control group (95 percent confidence interval, 526 to 756; P=0.003), a difference of 270 microg per day (95 percent confidence interval, 112 to 430). The rates of exacerbation were 0.49 episode per patient per year in the FE(NO) group (95 percent confidence interval, 0.20 to 0.78) and 0.90 in the control group (95 percent confidence interval, 0.31 to 1.49), representing a nonsignificant reduction of 45.6 percent (95 percent confidence interval for mean difference, -78.6 percent to 54.5 percent) in the FE(NO) group. There were no significant differences in other markers of asthma control, use of oral prednisone, pulmonary function, or levels of airway inflammation (sputum eosinophils). CONCLUSIONS With the use of FE(NO) measurements, maintenance doses of inhaled corticosteroids may be significantly reduced without compromising asthma control.
A stochastic‐conceptual analysis of one‐dimensional groundwater flow in nonuniform homogeneous media
The most realistic representation of a naturally occurring porous medium is a stochastic set of macroscopic elements in which the values of the three basic hydrogeologic parameters (hydraulic conductivity K, compressibility α, and porosity n) are defined by frequency distributions. A homogeneous formation under this representation is one in which the frequency distributions do not change through space. All soils and geologic formations, even the ones that are homogeneous, show random variations in the values of the hydrogeological parameters through space; that is, they are nonuniform, and a measure of the nonuniformity is provided by the standard deviation of the frequency distributions. If K and α are log normally distributed and n is normally distributed, and if we define Y = log K and C = log α, then the parameters Y, C, and n can be generated from a multivariate normal density function with means μy, μc, and μn, standard deviations σy, σc, and σn, and correlation coefficients ρyc, ρyn, and ρcn The analysis of groundwater flow in nonuniform media requires a stochastic-conceptual approach in which the effects of stochastic parameter distributions on predicted hydraulic heads are analyzed with the aid of a set of Monte Carlo solutions to the pertinent boundary value problems. In this study, two one-dimensional saturated flow problems are analyzed: steady state flow between two specified heads and transient consolidation of a clay layer. The primary output is the statistical distribution of hydraulic head ϕ, through space and time, as indicated by the mean values and their standard deviations Sϕ¯(x, t) Results show that the standard deviations of the input hydrogeologic parameters, particularly σy and σc, are important index properties; changes in their values lead to different responses for even when the means μy, μc, and μn are fixed. The degree of uncertainty associated with hydraulic head predictions increases as the degree of nonuniformity of the porous medium increases. For large values of σy and σc it becomes virtually impossible to obtain meaningful hydraulic head predictions. For transient flow the output distribution of hydraulic head values is almost never normal; in some cases it approaches a uniform distribution. The results of this study throw into question the validity of the hidden assumption that underlies all deterministic groundwater modeling; namely, that it is possible to select a single value for each flow parameter in a homogeneous but nonuniform medium that is somehow representative and hence define an ‘equivalent’ uniform porous medium. For transient flow there may be no way to define an equivalent medium. The fact that nine index parameters rather than three are required to describe a nonuniform geologic formation, the large uncertainties in predicted hydraulic heads for relatively simple flow problems in nonuniform soils, and the contention that there may be no simple way to define an equivalent uniform porous medium all have important implications in the development of groundwater flow theory and in its most fundamental applications.
Endothelium‐derived relaxing and contracting factors
Key discoveries in the past decade revealed that the endothelium can modulate the tone of underlying vascular smooth muscle by the synthesis/release of potent vasorelaxant (endothelium‐derived relaxing factors; EDRF) and vasoconstrictor substances (endothelium‐derived contracting factors; EDCF). It has become evident that the synthesis and release of these substances contribute to the multitude of physiological functions the vascular endothelium performs. Accumulating evidence suggests that at least one of the EDRFs is identical with nitric oxide (NO) or a labile nitroso compound, which is produced from L‐arginine by an NADPH‐ and Ca2+‐dependent enzyme, arginine oxidase. The existence of more than one chemically distinct EDRF has been proposed, including an endothelium‐derived hyperpolarizing factor (EDHF). The target of EDRF (NO) is soluble guanylate cyclase (increase in cyclic GMP) while EDHF appears to activate a K+‐channel in vascular smooth muscle. Recent data suggest that muscarinic receptor subtypes selectively mediate the release of EDRF(NO) (M2) and EDHF (M1). EDRF(NO) affects not only the underlying vascular smooth muscle, but also platelets, inhibiting their aggregation and adhesion to the endothelium. The antiaggregatory effect of EDRF is synergistic with prostacyclin, so their combined release may represent a physiological mechanism aimed at preventing thrombus formation. An additional proposed biological function of EDRF(NO) is cytoprotection by virtue of scavenging superoxide radicals. The endothelium can also mediate vasoconstriction by the release of a variety of endothelium‐derived contracting factors (EDCF). Other than the unique peptide endothelin, the nature of EDCFs has not yet been firmly established. Autoregulation of cerebral and renal blood flow and hypoxic pulmonary vasoconstriction may represent the physiological role of endothelium‐dependent vasoconstriction. Growing evidence indicates that the endothelium can serve as a unique mechanoreceptor, sensing and transducing physical stimuli (e.g., shear forces, pressure) into changes in vascular tone by the release of EDRFs or EDCFs. In physiological states, a delicate balance exists between endothelium‐derived vasodilators and vasoconstrictors. Alterations in this balance can result in local (vasospasm) and generalized (hypertension) increase in vascular tone and also in facilitated thrombus formation. Endothelial dysfunction may also contribute to the pathophysiology of angiopathies associated with hypercholesterolemia and atherosclerosis.
Adiponectin Stimulates Production of Nitric Oxide in Vascular Endothelial Cells*
Adiponectin is secreted by adipose cells and mimics many metabolic actions of insulin. However, mechanisms by which adiponectin acts are poorly understood. The vascular action of insulin to stimulate endothelial production of nitric oxide (NO), leading to vasodilation and increased blood flow is an important component of insulin-stimulated whole body glucose utilization. Therefore, we hypothesized that adiponectin may also stimulate production of NO in endothelium. Bovine aortic endothelial cells in primary culture loaded with the NO-specific fluorescent dye 4,5-diaminofluorescein diacetate (DAF-2 DA) were treated with lysophosphatidic acid (LPA) (a calcium-releasing agonist) or adiponectin (10 μg/ml bacterially produced full-length adiponectin). LPA treatment increased production of NO by ∼4-fold. Interestingly, adiponectin treatment significantly increased production of NO by ∼3-fold. Preincubation of cells with wortmannin (phosphatidylinositol 3-kinase inhibitor) blocked only adiponectin- but not LPA-mediated production of NO. Using phospho-specific antibodies, we observed that either adiponectin or insulin treatment (but not LPA treatment) caused phosphorylation of both Akt at Ser473 and endothelial nitric-oxide synthase (eNOS) at Ser1179 that was inhibitable by wortmannin. We next transfected bovine aortic endothelial cells with dominant-inhibitory mutants of Akt (Akt-AAA) or AMP-activated protein kinase (AMPK) (AMPKK45R). Neither mutant affected production of NO in response to LPA treatment. Importantly, only AMPKK45R, but not Akt-AAA, caused a significant partial inhibition of NO production in response to adiponectin. Moreover, AMPK-K45R inhibited phosphorylation of eNOS at Ser1179 in response to adiponectin but not in response to insulin. We conclude that adiponectin has novel vascular actions to directly stimulate production of NO in endothelial cells using phosphatidylinositol 3-kinase-dependent pathways involving phosphorylation of eNOS at Ser1179 by AMPK. Thus, the effects of adiponectin to augment metabolic actions of insulin in vivo may be due, in part, to vasodilator actions of adiponectin.
In situ construction of g-C3N4/g-C3N4 metal-free heterojunction for enhanced visible-light photocatalysis.
The photocatalytic performance of the star photocatalyst g-C3N4 was restricted by the low efficiency because of the fast charge recombination. The present work developed a facile in situ method to construct g-C3N4/g-C3N4 metal-free isotype heterojunction with molecular composite precursors with the aim to greatly promote the charge separation. Considering the fact that g-C3N4 samples prepared from urea and thiourea separately have different band structure, the molecular composite precursors of urea and thiourea were treated simultaneously under the same thermal conditions, in situ creating a novel layered g-C3N4/g-C3N4 metal-free heterojunction (g-g CN heterojunction). This synthesis method is facile, economic, and environmentally benign using easily available earth-abundant green precursors. The confirmation of isotype g-g CN heterojunction was based on XRD, HRTEM, valence band XPS, ns-level PL, photocurrent, and EIS measurement. Upon visible-light irradiation, the photogenerated electrons transfer from g-C3N4 (thiourea) to g-C3N4 (urea) driven by the conduction band offset of 0.10 eV, whereas the photogenerated holes transfer from g-C3N4 (urea) to g-C3N4 (thiourea) driven by the valence band offset of 0.40 eV. The potential difference between the two g-C3N4 components in the heterojunction is the main driving force for efficient charge separation and transfer. For the removal of NO in air, the g-g CN heterojunction exhibited significantly enhanced visible light photocatalytic activity over g-C3N4 alone and physical mixture of g-C3N4 samples. The enhanced photocatalytic performance of g-g CN isotype heterojunction can be directly ascribed to efficient charge separation and transfer across the heterojunction interface as well as prolonged lifetime of charge carriers. This work demonstrated that rational design and construction of isotype heterojunction could open up a new avenue for the development of new efficient visible-light photocatalysts.
Infections and airway inflammation in chronic obstructive pulmonary disease severe exacerbations.
RATIONALE Severe exacerbations of chronic obstructive pulmonary disease (COPD) are major causes of health care costs mostly related to hospitalization. The role of infections in COPD exacerbations is controversial. OBJECTIVES We investigated whether COPD exacerbations requiring hospitalization are associated with viral and/or bacterial infection and evaluated relationships among infection, exacerbation severity, assessed by reduction of FEV1, and specific patterns of airway inflammation. METHODS We examined 64 patients with COPD when hospitalized for exacerbations, and when in stable convalescence. We measured lung function, blood gases, and exhaled nitric oxide, and examined sputum for inflammation and for viral and bacterial infection. RESULTS Exacerbations were associated with impaired lung function (p < 0.01) and increased sputum neutrophilia (p < 0.001). Viral and/or bacterial infection was detected in 78% of exacerbations: viruses in 48.4% (6.2% when stable, p < 0.001) and bacteria in 54.7% (37.5% when stable, p = 0.08). Patients with infectious exacerbations (29.7% bacterial, 23.4% viral, 25% viral/bacterial coinfection) had longer hospitalizations (p < 0.02) and greater impairment of several measures of lung function (all p < 0.05) than those with noninfectious exacerbations. Patients with exacerbations with coinfection had more marked lung function impairment (p < 0.02) and longer hospitalizations (p = 0.001). Sputum neutrophils were increased in all exacerbations (p < 0.001) and were related to their severity (p < 0.001), independently of the association with viral or bacterial infections; sputum eosinophils were increased during (p < 0.001) virus-associated exacerbations. CONCLUSIONS Respiratory infections are associated with the majority of COPD exacerbations and their severity, especially those with viral/bacterial coinfection. Airway neutrophilia is related to exacerbation severity regardless of viral and/or bacterial infections. Eosinophilia is a good predictor of viral exacerbations.
Tadalafil Therapy for Pulmonary Arterial Hypertension
Background— Treatment options for pulmonary arterial hypertension target the prostacyclin, endothelin, or nitric oxide pathways. Tadalafil, a phosphodiesterase type-5 inhibitor, increases cGMP, the final mediator in the nitric oxide pathway. Methods and Results— In this 16-week, double-blind, placebo-controlled study, 405 patients with pulmonary arterial hypertension (idiopathic or associated), either treatment-naive or on background therapy with the endothelin receptor antagonist bosentan, were randomized to placebo or tadalafil 2.5, 10, 20, or 40 mg orally once daily. The primary end point was the change from baseline to week 16 in the distance walked in 6 minutes. Changes in World Health Organization functional class, clinical worsening, and health-related quality of life were also assessed. Patients completing the 16-week study could enter a long-term extension study. Tadalafil increased the distance walked in 6 minutes in a dose-dependent manner; only the 40-mg dose met the prespecified level of statistical significance (P<0.01). Overall, the mean placebo-corrected treatment effect was 33 m (95% confidence interval, 15 to 50 m). In the bosentan-naive group, the treatment effect was 44 m (95% confidence interval, 20 to 69 m) compared with 23 m (95% confidence interval, −2 to 48 m) in patients on background bosentan therapy. Tadalafil 40 mg improved the time to clinical worsening (P=0.041), incidence of clinical worsening (68% relative risk reduction; P=0.038), and health-related quality of life. The changes in World Health Organization functional class were not statistically significant. The most common treatment-related adverse events reported with tadalafil were headache, myalgia, and flushing. Conclusions— In patients with pulmonary arterial hypertension, tadalafil 40 mg was well tolerated and improved exercise capacity and quality of life measures and reduced clinical worsening.
Efficient model-based 3D tracking of hand articulations using Kinect
We present a novel solution to the problem of recovering and tracking the 3D position, orientation and full articulation of a human hand from markerless visual observations obtained by a Kinect sensor. We treat this as an optimization problem, seeking for the hand model parameters that minimize the discrepancy between the appearance and 3D structure of hypothesized instances of a hand model and actual hand observations. This optimization problem is effectively solved using a variant of Particle Swarm Optimization (PSO). The proposed method does not require special markers and/or a complex image acquisition setup. Being model based, it provides continuous solutions to the problem of tracking hand articulations. Extensive experiments with a prototype GPU-based implementation of the proposed method demonstrate that accurate and robust 3D tracking of hand articulations can be achieved in near real-time (15Hz).
Physiology of nitric oxide in skeletal muscle.
In the past five years, skeletal muscle has emerged as a paradigm of "nitric oxide" (NO) function and redox-related signaling in biology. All major nitric oxide synthase (NOS) isoforms, including a muscle-specific splice variant of neuronal-type (n) NOS, are expressed in skeletal muscles of all mammals. Expression and localization of NOS isoforms are dependent on age and developmental stage, innervation and activity, history of exposure to cytokines and growth factors, and muscle fiber type and species. nNOS in particular may show a fast-twitch muscle predominance. Muscle NOS localization and activity are regulated by a number of protein-protein interactions and co- and/or posttranslational modifications. Subcellular compartmentalization of the NOSs enables distinct functions that are mediated by increases in cGMP and by S-nitrosylation of proteins such as the ryanodine receptor-calcium release channel. Skeletal muscle functions regulated by NO or related molecules include force production (excitation-contraction coupling), autoregulation of blood flow, myocyte differentiation, respiration, and glucose homeostasis. These studies provide new insights into fundamental aspects of muscle physiology, cell biology, ion channel physiology, calcium homeostasis, signal transduction, and the biochemistry of redox-related systems.
Endogenous nitric oxide is present in the exhaled air of rabbits, guinea pigs and humans.
The presence of nitric oxide (NO) in the exhaled air of humans and of anaesthetized rabbits and guinea pigs was demonstrated by chemiluminescence, diazotization and mass spectrometry. This NO is endogenously produced in the lung by an NO synthase, since its generation in guinea pigs and rabbits was inhibited by N omega-nitro-L-arginine methyl ester and NG-monomethyl-L-arginine, inhibitors of this enzyme. The effect of the inhibitors was reversed by the precursor of NO synthesis, L-arginine. Since NO is produced by normal vascular endothelium for the physiological regulation of blood flow and pressure and also by activated macrophages to contribute to non-specific immunity, our experiments suggest that NO may play both vascular regulatory and host defence roles in pulmonary physiology and pathophysiology.
Elevated blood pressures in mice lacking endothelial nitric oxide synthase.
Nitric oxide produced in endothelial cells affects vascular tone. To investigate the role of endothelial nitric oxide synthase (eNOS) in blood pressure regulation, we have generated mice heterozygous (+/-) or homozygous (-/-) for disruption of the eNOS gene. Immunohistochemical staining with anti-eNOS antibodies showed reduced amounts of eNOS protein in +/- mice and absence of eNOS protein in -/- mutant mice. Male or female mice of all three eNOS genotypes were indistinguishable in general appearance and histology, except that -/- mice had lower body weights than +/+ or +/- mice. Blood pressures tended to be increased (by approximately 4 mmHg) in +/- mice compared with +/+, while -/- mice had a significant increase in pressure compared with +/+ mice (approximately 18 mmHg) or +/- mice (approximately 14 mmHg). Plasma renin concentration in the -/- mice was nearly twice that of +/+ mice, although kidney renin mRNA was modestly decreased in the -/- mice. Heart rates in the -/- mice were significantly lower than in +/- or +/+ mice. Appropriate genetic controls show that these phenotypes in F2 mice are due to the eNOS mutation and are not due to sequences that might differ between the two parental strains (129 and C57BL/6J) and are linked either to the eNOS locus or to an unlinked chromosomal region containing the renin locus. Thus eNOS is essential for maintenance of normal blood pressures and heart rates. Comparisons between the current eNOS mutant mice and previously generated inducible nitric oxide synthase mutants showed that homozygous mutants for the latter differ in having unaltered blood pressures and heart rates; both are susceptible to lipopolysaccharide-induced death.
Molecular mechanisms involved in the regulation of the endothelial nitric oxide synthase.
The endothelial nitric oxide synthase (eNOS), the expression of which is regulated by a range of transcriptional and posttranscriptional mechanisms, generates nitric oxide (NO) in response to a number of stimuli. The physiologically most important determinants for the continuous generation of NO and thus the regulation of local blood flow are fluid shear stress and pulsatile stretch. Although eNOS activity is coupled to changes in endothelial cell Ca(2+) levels, an increase in Ca(2+) alone is not sufficient to affect enzyme activity because the binding of calmodulin (CaM) and the flow of electrons from the reductase to the oxygenase domain of the enzyme is dependent on protein phosphorylation and dephosphorylation. Two amino acids seem to be particularly important in regulating eNOS activity and these are a serine residue in the reductase domain (Ser(1177)) and a threonine residue (Thr(495)) located within the CaM-binding domain. Simultaneous alterations in the phosphorylation of Ser(1177) and Thr(495) in response to a variety of stimuli are regulated by a number of kinases and phosphatases that continuously associate with and dissociate from the eNOS signaling complex. eNOS associated proteins, such as caveolin, heat shock protein 90, eNOS interacting protein, and possibly also motor proteins provide the scaffold for the formation of the protein complex as well as its intracellular localization.
An Experimental Comparison of Range Image Segmentation Algorithms
A methodology for evaluating range image segmentation algorithms is proposed. This methodology involves (1) a common set of 40 laser range finder images and 40 structured light scanner images that have manually specified ground truth and (2) a set of defined performance metrics for instances of correctly segmented, missed, and noise regions, over- and under-segmentation, and accuracy of the recovered geometry. A tool is used to objectively compare a machine generated segmentation against the specified ground truth. Four research groups have contributed to evaluate their own algorithm for segmenting a range image into planar patches.
Metrics for evaluating 3D medical image segmentation: analysis, selection, and tool
BackgroundMedical Image segmentation is an important image processing step. Comparing images to evaluate the quality of segmentation is an essential part of measuring progress in this research area. Some of the challenges in evaluating medical segmentation are: metric selection, the use in the literature of multiple definitions for certain metrics, inefficiency of the metric calculation implementations leading to difficulties with large volumes, and lack of support for fuzzy segmentation by existing metrics.ResultFirst we present an overview of 20 evaluation metrics selected based on a comprehensive literature review. For fuzzy segmentation, which shows the level of membership of each voxel to multiple classes, fuzzy definitions of all metrics are provided. We present a discussion about metric properties to provide a guide for selecting evaluation metrics. Finally, we propose an efficient evaluation tool implementing the 20 selected metrics. The tool is optimized to perform efficiently in terms of speed and required memory, also if the image size is extremely large as in the case of whole body MRI or CT volume segmentation. An implementation of this tool is available as an open source project.ConclusionWe propose an efficient evaluation tool for 3D medical image segmentation using 20 evaluation metrics and provide guidelines for selecting a subset of these metrics that is suitable for the data and the segmentation task.
A Tutorial on Text-Independent Speaker Verification
This paper presents an overview of a state-of-the-art text-independent speaker verification system. First, an introduction proposes a modular scheme of the training and test phases of a speaker verification system. Then, the most commonly speech parameterization used in speaker verification, namely, cepstral analysis, is detailed. Gaussian mixture modeling, which is the speaker modeling technique used in most systems, is then explained. A few speaker modeling alternatives, namely, neural networks and support vector machines, are mentioned. Normalization of scores is then explained, as this is a very important step to deal with real-world data. The evaluation of a speaker verification system is then detailed, and the detection error trade-off (DET) curve is explained. Several extensions of speaker verification are then enumerated, including speaker tracking and segmentation by speakers. Then, some applications of speaker verification are proposed, including on-site applications, remote applications, applications relative to structuring audio information, and games. Issues concerning the forensic area are then recalled, as we believe it is very important to inform people about the actual performance and limitations of speaker verification systems. This paper concludes by giving a few research trends in speaker verification for the next couple of years.
Validity and reliability of the Nintendo Wii Balance Board for assessment of standing balance.
Impaired standing balance has a detrimental effect on a person's functional ability and increases their risk of falling. There is currently no validated system which can precisely quantify center of pressure (COP), an important component of standing balance, while being inexpensive, portable and widely available. The Wii Balance Board (WBB) fits these criteria, and we examined its validity in comparison with the 'gold standard'-a laboratory-grade force platform (FP). Thirty subjects without lower limb pathology performed a combination of single and double leg standing balance tests with eyes open or closed on two separate occasions. Data from the WBB were acquired using a laptop computer. The test-retest reliability for COP path length for each of the testing devices, including a comparison of the WBB and FP data, was examined using intraclass correlation coefficients (ICC), Bland-Altman plots (BAP) and minimum detectable change (MDC). Both devices exhibited good to excellent COP path length test-retest reliability within-device (ICC=0.66-0.94) and between-device (ICC=0.77-0.89) on all testing protocols. Examination of the BAP revealed no relationship between the difference and the mean in any test, however the MDC values for the WBB did exceed those of the FP in three of the four tests. These findings suggest that the WBB is a valid tool for assessing standing balance. Given that the WBB is portable, widely available and a fraction of the cost of a FP, it could provide the average clinician with a standing balance assessment tool suitable for the clinical setting.
Management of the Difficult Adult Airway With Special Emphasis on Awake Tracheal Intubation
Difficulty in managing the airway is the single most important cause of major anesthesia-related morbidity and mortality. Successful management of a difficult airway begins with recognizing the potential problem. All patients should be examined for their ability to open their mouth widely and for the structures visible upon mouth opening, the size of the mandibular space, and ability to assume the sniff position. If there is a good possibility that intubation and/or ventilation by mask will be difficult, then the airway should be secured while the patient is still awake. In order for an awake intubation to be successful, it is absolutely essential that the patient be properly prepared; otherwise, the anesthesiologist will simply fulfill a self-defeating prophecy. Once the patient is properly prepared, it is likely that any one of a number of intubation techniques will be successful. If the patient is already anesthetized and/or paralyzed and intubation is found to be difficult, many repeated attempts at intubation should be avoided because progressive development of laryngeal edema and hemorrhage will develop and the ability to ventilate the lungs via mask consequently may be lost. After several attempts at intubation, it may be best to awaken the patient, do a semielective tracheostomy, or proceed with the case using mask ventilation. In the event that the ability to ventilate via mask is lost and the patient's lungs still cannot be ventilated, TTJV should be instituted immediately. Tracheal extubation of a patient with a difficult airway over a jet stylet permits a controlled, gradual, and reversible (in that ventilation and reintubation is possible at any time) withdrawal from the airway. Significant advances in the management of the difficult airway have occurred in recent years. Eighty percent of the 127 references in this article were published after 1985. However, there is much more to learn with regard to recognition of the difficult airway, preparation of the patient for an awake intubation, new techniques of endotracheal intubation, and establishment of gas exchange in patients who cannot be intubated or ventilated by mask. As the anesthesiologist's ability to manage the difficult airway significantly improves, respiratory-related morbidity and mortality will decrease.
On Decomposing the Causes of Health Sector Inequalities with an Application to Malnutrition Inequalities in Vietnam
A method for decomposing inequalities in the health sector into their causes is developed and applied to data on child malnutrition in Vietnam. Wagstaff, van Doorslaer, and Watanabe propose a method for decomposing inequalities in the health sector into their causes, by coupling the concentration index with a regression framework. They also show how changes in inequality over time, and differences across countries, can be decomposed into the following: - Changes due to changing inequalities in the determinants of the variable of interest. - Changes in the means of the determinants. - Changes in the effects of the determinants on the variable of interest. The authors illustrate the method using data on child malnutrition in Vietnam. They find that inequalities in height-for-age in 1993 and 1998 are accounted for largely by inequalities in household consumption and by unobserved influences at the commune level. And they find that an increase in such inequalities is accounted for largely by changes in these two influences. In the case of household consumption, rising inequalities play a part, but more important have been the inequality - increasing effects of rising average consumption and the increased protective effect of consumption on nutritional status. In the case of unobserved commune-level influences, rising inequality and general improvements seem to have been roughly equally important in accounting for rising inequality in malnutrition. This paper - a joint product of Public Services for Human Development, Development Research Group, and the Development Data Group - is part of a larger effort in the Bank to investigate the links between health and poverty. The authors may be contacted at awagstaff@worldbank.org, vandoorslaer@econ.bmg.eur.nl., or nwatanabe@worldbank.org.
Analyzing Intention in Utterances
This paper describes a model of cooperative behavior and describes how such a model can be applied in a natural language understanding system. We assume that agents attempt to recognize the plans of other agents and, then, use this plan when deciding what response to make. In particular, we show that, given a setting in which purposeful dialogues occur, this model can account for responses that provide more information that explicitly requested and for appropriate responses to both short sentence fragments and indirect speech acts.
Score Normalization for Text-Independent Speaker Verification Systems
Auckenthaler, Roland, Carey, Michael, and Lloyd-Thomas, Harvey, Score Normalization for Text-Independent Speaker Verification Systems, Digital Signal Processing10(2000), 42?54.This paper discusses several aspects of score normalization for text-independent speaker verification. The theory of score normalization is explained using Bayes' theorem and detection error trade-off plots. Based on the theory, the world, cohort, and zero normalization techniques are explained. A novel normalization technique, test normalization, is introduced. Experiments showed significant improvements for this new technique compared to the standard techniques. Finally, there is a discussion of the use of additional knowledge to further improve the normalization methods. Here, the test normalization method is extended to use knowledge of the handset type.
neural network artificial neural network deep learning convolutional neural network convolutional neural deep neural network image segmentation deep neural medical image magnetic resonance digital signal magnetic resonance imaging mixture model gaussian mixture model resonance imaging level set confidence interval factor analysi gesture recognition fuzzy c-mean motor control risk factor hand gesture segmentation algorithm motion capture loss function blood pressure speaker verification level set method blood vessel verification system hand gesture recognition amino acid medical image segmentation image segmentation algorithm world health microsoft kinect medical image analysi kinect sensor gesture recognition system speaker verification system cell type immune response groundwater flow animal model special emphasi automatic speaker text-independent speaker microsoft kinect sensor health sector liver disease text-independent speaker verification automatic speaker verification speaker recognition evaluation endothelial cell intraclass correlation medical imaging application organic chemical nitric oxide monoclonal antibody smooth muscle nist speaker recognition image segmentation play text-dependent speaker image segmentation task text-dependent speaker verification based speaker verification oxidative stres robust speaker verification field of study central role muscle cell vascular disease volumetric medical image research consortium speaker verification task standing balance treatment outcome human papillomaviru reactive oxygen species smooth muscle cell joint factor analysi kinect device septic shock robust hand reactive oxygen pulmonary hypertension joint factor c-reactive protein robust hand gesture chronic liver disease vascular smooth muscle tumor necrosi exhaled air vascular smooth control chapter total variability space superoxide dismutase study chapter variability space processing chapter artery and vein nervous system disorder muscle, smooth, vascular intrahepatic cholangiocarcinoma sodium nitroprusside nos3 gene nos3 protein, human factor v deficiency endothelium, vascular guanylate cyclase nitric oxide pathway relaxation of smooth muscle cns disorder hypertensive disease gucy2c protein, human cyclic gmp review [publication type] transcription, genetic leukemia, b-cell activation action hematological disease cultured cell line protein isoform biologic segmentation morbidity - disease rate liver carcinoma phosphoric monoester hydrolase blood supply aspect guanosine monophosphate blood platelet smooth muscle (tissue) nitric oxide synthase vasodilator agent pulmonary artery structure vascular constriction (function)