bluuebunny/crossref_metadata_2025 huggingface dataset:
Decennial Analysis of Interventional Left Atrial Appendage Closure
Authors: SCHMIDT BORIS , BORDIGNON STEFANO , FUERNKRANZ ALEXANDER , PERROTTA LAURA , SCHERER DETLEF , CHUN K.R. JULIAN
Published: May 2015

Long‐Term Follow‐Up of LAA Occlusion

Introduction

Data on long‐term follow‐up (LTFU) after interventional closure of the left atrial appendage (LAAC) in patients with nonvalvular atrial fibrillation (AF) are scarce. We sought to determine the outcome of patients after LAAC with the first generation device.

Methods and Results

The Cardioangiologisches Centrum Bethanien (CCB) LAAC registry database was analyzed. Between October 2001 and July 2007, 45 AF patients (23 male, mean age 71 ± 6 years; mean CHA2DS2‐VaSc 4.3 ± 1.7 [range 1–7]; mean HASBLED score 3.3 ± 1.2 [1–5]) received LAAC. Postimplant dual‐platelet inhibition with clopidogrel 75 mg/day and aspirine (ASA) 300 mg/day was prescribed for 6 months, followed by ASA 300 mg indefinitely. The primary endpoint was defined as any thrombembolic complication and/or any bleeding complication. The median FU was 7.4 years (1–12.4 years) resulting in 292 patient years. Fourteen patients died due to heart failure (n = 4), noncardiac reasons (n = 7), or due to unknown etiology (n = 3). No patient died from a bleeding or a stroke. Five ischemic strokes occurred at a median of 794 days (range 304–3,706 days) after LAAC. The observed annual stroke rate was 1.7% (RR 0.43; 95% CI 0.24–0.74; P = 0.0028). In 6 patients bleeding occurred (2 acute procedural, 4 during follow‐up). The observed annual bleeding rate was 2.1% (RR 0.56; 95% CI 0.48–0.66; P < 0.0001).

Conclusion

During LTFU after LAAC in patients with nonvalvular AF, lower event rates than expected are observed for both thrombembolic and bleeding complications.
Guidelines of care for vascular lasers and intense pulse light sources from the European Society for Laser Dermatology
Authors: Adamič M. , Pavlović M.D. , Troilius Rubin A. , Palmetun‐Ekbäck M. , Boixeda P.
Published: May 2015

Aim

Lasers and non‐coherent intense pulse light sources (IPLS) are based on the principle of selective photothermolysis and can be used for the treatment of many vascular skin lesions. A variety of lasers has been developed for the treatment of congenital and acquired vascular lesions which incorporate these concepts into their design. Although laser and light sources are very popular due to their non‐invasive nature, caution should be considered by practitioners and patients to avoid permanent side‐effects. The aim of these guidelines is to give evidence‐based recommendations for the use of lasers and IPLS in the treatment of vascular lesions.

Methods

These guidelines were produced by a Consensus Panel made up of experts in the field of vascular laser surgery under the auspices of the European Society of Laser Dermatology. Recommendations on the use of vascular lasers and IPLS were made based on the quality of evidence for efficacy, safety, tolerability, cosmetic outcome, patient satisfaction/preference and, where appropriate, on the experts’ opinion. The recommendations of these guidelines are graded according to the American College of Chest Physicians Task Force recommendations on Grading Strength of Recommendations and Quality of Evidence in Clinical Guidelines.

Results

Lasers and IPLS are very useful and sometimes the only available method to treat various vascular lesions. It is of a paramount importance that the type of laser or IPLS and their specific parameters are adapted to the indication but also that the treating physician is familiar with the device to be used. The crucial issue in treating vascular lesions is to recognize the immediate end‐point after laser treatment. This is the single most important factor to ensure both the efficacy of the treatment and avoidance of serious side‐effects.
Job satisfaction and horizontal violence in hospital staff registered nurses: the mediating role of peer relationships
Authors: Purpora Christina , Blegen Mary A
Published: May 2015

Aims and objectives

To describe the association between horizontal violence and job satisfaction in hospital staff registered nurses and the degree to which peer relationships mediates the relationship. Additionally, the association between nurse and work characteristics and job satisfaction were determined.

Background

Horizontal violence is a major predictor of nurses' job satisfaction. Yet, not enough is known about the relationship between these variables. Job satisfaction is an important variable to study because it is a predictor of patient care quality and safety internationally. Peer relationships, a job satisfier for nurses, was identified as a potential mediator in the association between horizontal violence and job satisfaction.

Design

Cross‐sectional mediational model testing.

Methods

An anonymous four‐part survey of a random sample of 175 hospital staff registered nurses working in California provided the data. Data about horizontal violence, peer relationships, job satisfaction, and nurse and work characteristics were collected between March–August 2010.

Results

A statistically significant negative relationship was found between horizontal violence and peer relationships, job satisfaction and a statistically significant positive relationship was found between peer relationships and job satisfaction. Peer relationships mediated the association between horizontal violence and job satisfaction. Job satisfaction was reported as higher by nurses who worked in teaching hospitals. There were no statistically significant differences in job satisfaction based on gender, ethnicity, basic registered nurse education, highest degree held, size of hospital or clinical area.

Conclusions

The results suggest that peer relationships can attenuate the negative relationship between horizontal violence and job satisfaction. This adds to the extant literature on the relationship between horizontal violence and job satisfaction.

Relevance to clinical practice

The findings highlight peer relationships as an important factor when considering effective interventions that foster hospital staff registered nurses' job satisfaction in the presence of horizontal violence.
Ineffective breathing pattern in children and adolescents with congenital heart disease: accuracy of defining characteristics
Authors: Beltrão Beatriz Amorim , Herdman Tracy Heather , Pascoal Lívia Maia , Chaves Daniel Bruno Resende , da Silva Viviane Martins , de Oliveira Lopes Marcos Venícios
Published: May 2015

Aims and objectives

The purpose of this study was to assess the prevalence ofineffective breathing patternand the accuracy of its defining characteristics, among children and adolescents with congenital heart disease.

Background

TheNANDAInternational nursing diagnosis,ineffective breathing pattern, has been noted to have high prevalence in different clinical contexts and age groups. Despite that, nurses continue to report difficulties in confirming this diagnosis. The lack of data regarding the sensitivity, specificity and predictive values of the defining characteristics contribute to decreased certainty in diagnosingineffective breathing pattern.

Design

A diagnostic accuracy study.

Methods

This study of diagnostic accuracy was conducted with 61 children and adolescents with congenital heart disease. Two nurses were trained by the primary investigator on use of defining characteristics in the diagnostic process forineffective breathing pattern.

Results

Ineffective breathing patternwas present in 26·2% of the children and adolescents sampled. When analysing the defining characteristics,alterations in depth of breathing,showed high values of sensitivity and specificity. In addition,orthopnoea,tachypnoeaanduse of accessory muscles to breathe,showed high values of specificity; dyspnoeashowed high values of sensitivity. Finally,assumption of three‐point position,bradypnoeaandincreased anterior–posterior diameterwere not found to be statistically significant for this sample population.

Conclusion

Five defining characteristics ofineffective breathing patternpresented measures of accuracy with statistically significant values in children with congenital heart disease.

Relevance to clinical practice

The findings can help nurses during the diagnostic process, as they identify which defining characteristics can be used to confirm or rule out the probability of occurrence of the diagnosis.
Idiosyncratic Cash Flows and Systematic Risk
Authors: BABENKO ILONA , BOGUTH OLIVER , TSERLUKEVICH YURI
Published: May 2015

We show that unpriced cash flow shocks contain information about future priced risk. A positive idiosyncratic shock decreases the sensitivity of firm value to priced risk factors and simultaneously increases firm size and idiosyncratic risk. A simple model can therefore explain book‐to‐market and size anomalies, as well as the negative relation between idiosyncratic volatility and stock returns. Empirically, we find that anomalies are more pronounced for firms with high idiosyncratic cash flow volatility. More generally, our results imply that any economic variable correlated with the history of idiosyncratic shocks can help to explain expected stock returns.
CEO Turnover and Relative Performance Evaluation
Authors: JENTER DIRK , KANAAN FADI
Published: May 2015

This paper shows that CEOs are fired after bad firm performance caused by factors beyond their control. Standard economic theory predicts that corporate boards filter out exogenous industry and market shocks from firm performance before deciding on CEO retention. Using a hand‐collected sample of 3,365 CEO turnovers from 1993 to 2009, we document that CEOs are significantly more likely to be dismissed from their jobs after bad industry and, to a lesser extent, after bad market performance. A decline in industry performance from the 90thto the 10thpercentile doubles the probability of a forced CEO turnover.
The Role of Institutional Investors in Voting: Evidence from the Securities Lending Market
Authors: AGGARWAL REENA , SAFFI PEDRO A. C. , STURGESS JASON
Published: May 2015

This paper investigates voting preferences of institutional investors using the unique setting of the securities lending market. Investors restrict lendable supply and/or recall loaned shares prior to the proxy record date to exercise voting rights. Recall is higher for investors with greater incentives to monitor, for firms with poor performance or weak governance, and for proposals where returns to governance are likely higher. At the subsequent vote, recall is associated with less support for management and more support for shareholder proposals. Our results indicate that institutions value their vote and use the proxy process to affect corporate governance.
Estimating themissing species bias in plant trait measurements
Authors: Sandel Brody , Gutiérrez Alvaro G. , Reich Peter B. , Schrodt Franziska , Dickie John , Kattge Jens
Published: May 2015

Aim

Do plant trait databases represent a biased sample of species, and if so, can that bias be corrected? Ecologists are increasingly collecting and analysing data on plant functional traits, and contributing them to large plant trait databases. Many applications of such databases involve merging trait measurements with other data such as species distributions in vegetation plots; a process that invariably produces matrices with incomplete trait and species data. Typically, missing data are simply ignored and it is assumed that the missing species are missing at random.

Methods

Here, we argue that this assumption is unlikely to be valid and propose an approach for estimating the strength of the bias regarding which species are represented in trait databases. The method leverages the fact that, within a given database, some species have many measurements of a trait and others have few (high vs low measurement intensity). In the absence of bias, there should be no relationship between measurement intensity and trait values. We demonstrate the method using five traits that are part of the TRY database, a global archive of plant traits. Our method also leads naturally to a correction for this bias, which we validate and apply to two examples.

Results

Specific leaf area and seed mass were strongly positively biased (frequently measured species had higher trait values than rarely measured species), leaf nitrogen per unit mass and maximum height were moderately negatively biased, and maximum photosynthetic capacity per unit leaf area was weakly negatively biased. The bias‐correction method yielded greatly improved estimates in the validation tests for the two most biased traits. Further, in our two applications, ecological interpretations were shown to be sensitive to uncorrected bias in the data.

Conclusions

Species inclusion in trait databases appears to be strongly biased in some cases, and failure to correct this can lead to incorrect conclusions.
New Firms as Employers: The Wage Penalty for Voluntary and Involuntary Job Switchers
Authors: Nyström Kristina , Zhetibaeva Elvung Gulzat
Published: May 2015

According to previous research, new firms pay lower wages. However, previous studies have been unable to control for the possibility that the opportunity costs of accepting employment at new firms may differ across individuals. In this paper, we investigate whether a wage penalty for being employed at a new firm exists if we take the individual employee's experience and status in the labour market into consideration. We focus on individuals who decide to switch jobs and use matched employee–employer data about all firms and employees in Sweden for the period 1998–2010. Our results show that the share of job transitions into lower wages are higher for those who switch to new firms compared with incumbent firms (40 per cent and 31 per cent, respectively). Our endogenous wage equation estimates indicate that being an involuntary job switcher has an equally negative effect on wages at both new and incumbent firms. However, the positive effect of education on wages is more pronounced for job switchers selecting into incumbent firms.
Predictive value of routine esophageal high‐resolution manometry for gastro‐esophageal reflux disease
Authors: van Hoeij F. B. , Smout A. J. , Bredenoord A. J.
Published: May 2015

Background

Using conventional manometry, gastro‐esophageal reflux disease (GERD) was associated with a reduced lower esophageal sphincter (LES) pressure and impaired peristalsis. However, with a large overlap between GERD patients and controls, these findings are of limited clinical relevance. It is uncertain whether the more detailed information of high‐resolution manometry (HRM) can discriminate GERD patients. Therefore, we aimed to determine to which extent HRM findings can predict GERD.

Methods

HRM measurements in 69 patients with GERD and 40 healthy subjects were compared and the predictive value of HRM for the diagnosis of GERD was explored.

Key Results

GERD patients had a significantly lower contraction amplitude (55 vs 64 mmHg; p = 0.045) and basal LES pressure (10 vs 13.2 mmHg; p = 0.034) than healthy controls. GERD patients more often had a hiatal hernia than healthy subjects (30% vs 7%; p = 0.005). Patients with reflux esophagitis had a lower DCI than patients without reflux esophagitis (558 vs 782 mmHg cm s; p = 0.045). No significant difference was seen in contractile front velocity, distal latency, number of peristaltic breaks, residual LES pressure and LES length. On multivariate logistic regression analysis, both esophagogastric junction type I (OR 4.971; 95% CI 1.33–18.59; p = 0.017) and mean wave amplitude (OR 0.95; 95% CI 0.90–0.98; p = 0.013) were found to be independent predictors of GERD. However, the sensitivity and specificity of these findings were low.

Conclusions & Inferences

Hiatal hernia, low contraction amplitude and LES pressure are associated with GERD, but do not predict the disease with sufficient accuracy. Routine esophageal HRM can therefore not be used to distinguish GERD patients from healthy subjects.
ASSESSING UNCERTAINTY IN A MULTISPECIES AGE‐STRUCTURED ASSESSMENT FRAMEWORK: THE EFFECTS OF DATA LIMITATIONS AND MODEL ASSUMPTIONS
Authors: VAN KIRK KRAY F. , QUINN TERRANCE J. , COLLIE JEREMY S. , A'MAR Z. T.
Published: May 2015

Performance of a multispecies age‐structured assessment (MSASA) model in the Gulf of Alaska (GOA) relative to changes in data and model assumptions was examined through simulation exercises. Species included arrowtooth flounder (Atheresthes stomias), Pacific cod (Gadus macrocephalus), walleye pollock (Theragra chalcogramma), Pacific halibut (Hippoglossus stenolepis), and Steller sea lion (Eumetopias jubatus). Age‐specific predation mortality was estimated as a flexible function of predator and prey abundances and fitted to diet data. Simulated data sets were constructed by applying random error to estimates of catch, survey, and diet data from an operating model, whose structure was identical to that of the estimating model. Simulations explored the effects of data variability, mismatched assumptions regarding model structure, and lack of diet data on model performance. Model misspecification and uninformative diet data had the greatest influence on model performance. Given the current emphasis on the development of ecosystem‐based models and management, prioritizing the rigorous sampling of diet data would best facilitate the development of predation models useful to management agencies.
Color Doppler Ultrasound Follow‐Up of Infantile Hemangiomas and Peripheral Vascularity in Patients Treated with Propranolol
Authors: Kutz Ana M. , Aranibar Ligia , Lobos Nelson , Wortsman Ximena
Published: May 2015

Background

Infantile hemangiomas (IHs) are the most common vascular tumors in childhood. Diagnosis of IHs is usually clinical, however, to determine the actual dimensions of the lesion or the anatomic changes that occur during its evolution and treatment, a color Doppler ultrasound (CDU) examination can be performed. To date, there are few publications that assess the sonographic response to propranolol in IHs, and to our knowledge, none that consider simultaneous evaluation of both intralesional and normal peripheral blood vessels in these cases.

Objective

Evaluation of the anatomic effect of propranolol in IHs and peripheral blood vessels using CDU.

Methods

A cohort study was performed in 10 pediatric patients with a diagnosis of IH in whom systemic therapy with propranolol was indicated. The patients underwent a baseline and 3‐month follow‐up CDUs of the tumor and the main peripheral vessels of the right upper extremity.

Results

The group was composed of 7 (70%) girls and 3 (30%) boys. The average CDU decrease in size of the longitudinal axis was 11%; of the transverse axis, 24%; tumor thickness, 30%; and intralesional vessel thickness, 46%. Hemangioma volume measured by CDU decreased an average of 51%. The thickness of the peripheral vessels did not change significantly between the baseline and 3‐month follow‐up CDUs.

Conclusion

CDU permits noninvasive quantification of the changes in IHs and peripheral vessels in patients receiving propranolol therapy. In our cohort of cases there was a significant reduction in tumor volume; however, peripheral vascularity was not significantly affected.
Pediatric Lichen Sclerosus: A Review of the Epidemiology and Treatment Options
Authors: Tong Lana X. , Sun Grace S. , Teng Joyce M.C.
Published: May 2015

Lichen sclerosus (LS) is a rare, chronic, inflammatory disease of the skin that primarily affects postmenopausal women but may occur in men and children as well. Approximately 7% to 15% of cases are believed to occur in children. The epidemiologic data for LS have been limited and treatment options are not well studied, particularly in children. We reviewed new developments available in the current literature on the epidemiology and management of LS for children.
Novel cystathionine β‐synthase gene mutations in a Filipino patient with classic homocystinuria
Authors: Silao Catherine Lynn T. , Fabella Terence Diane F. , Rama Kahlil Izza D. , Estrada Sylvia C.
Published: May 2015

Abstract

Background

Classic homocystinuria due to cystathionine β‐synthase (CBS) deficiency is an autosomal recessive disorder of sulfur metabolism. Clinical manifestations include mental retardation, dislocation of the optic lens (ectopia lentis), skeletal abnormalities and a tendency to thromboembolic episodes. We present the first mutational analysis of CBS in a Filipino patient with classic homocystinuria.

Methods

Genomic DNA was extracted from peripheral blood collected from a diagnosed Filipino patient with classic homocystinuria. The entire coding region of CBS (17 exons) was amplified using polymerase chain reaction and bidirectionally sequenced using standard protocols.

Results

The patient was found to be compound heterozygous for two novel mutations, g.13995G>A [c.982G>A; p.D328K] and g.15860‐15868dupGCAGGAGCT [c.1083‐1091dupGCAGGAGCT; p. Q362‐L364dupQEL]. Four known single‐nucleotide polymorphisms (rs234706, rs1801181, rs706208 and rs706209) were also detected in the present patient's CBS. The patient was heterozygous for all the identified alleles.

Conclusions

This is the first mutational analysis of CBS done in a Filipino patient with classic homocystinuria who presented with a novel duplication mutation and a novel missense mutation. Homocystinuria due to CBS deficiency is a heterogeneous disorder at the molecular level.
Proposal for novel histological findings of colorectal liver metastases with preoperative chemotherapy
Authors: Ishida Kazuyuki , Uesugi Noriyuki , Hasegawa Yasushi , Sugimoto Ryo , Takahara Takeshi , Otsuka Koki , Nitta Hiroyuki , Kawasaki Tomonori , Wakabayashi Go , Sugai Tamotsu
Published: May 2015

This study aimed to clarify the histological characteristics related to preoperative chemotherapy for colorectal liver metastases (CRLM). Sixty‐three patients with CRLM were divided into two groups: CRLM with chemotherapy (41 cases, group A) and CRLM without chemotherapy (22 cases; surgical treatment alone, group S) to identify the histological differences associated with chemotherapy. In addition, we investigated the effects of combination chemotherapy on the histology of metastatic lesions. Infarct‐like necrosis (ILN), three‐zonal changes, and cholesterol clefts were more frequent in group A than in group S (P < 0.05). ILN and three‐zonal changes were more common in the 5‐FU with leucovorin and oxaliplatin (FOLFOX), or 5‐FU with leucovorin and irinotecan (FOLFIRI) with or without additional bevacizumab groups than in group S (P < 0.05). Cholesterol clefts in the FOLFOX or FOLFIRI with bevacizumab group and foamy macrophages in the FOLFOX or FOLFIRI group were more common than in group S (P < 0.05). Cases with more than three of the four histological findings—i.e. ILN, three‐zonal changes, cholesterol clefts, and foamy macrophages—were more frequent in the FOLFOX or FOLFIRI with or without additional bevacizumab groups than in group S (P < 0.05). We showed histological findings for every representative chemotherapy regimen for CRLM to clarify the effects of preoperative chemotherapy.
Dieback and mortality of Nothofagus in Britain: ecology, pathogenicity and sporulation potential of the causal agent Phytophthora pseudosyringae
Authors: Scanu B. , Webber J. F.
Published: May 2015

Since 2009 extensive dieback and mortality of Nothofagus obliqua, associated with bleeding cankers on stems and branches, has been observed in the UK. The causal agent was identified as Phytophthora pseudosyringae, based on morphological and analysis of the internal transcribed spacer (ITS) sequences. Between 2011 and 2013, a survey assessed the frequency and nature of these P. pseudosyringae infections. Mature trees of Nothofagus with stem lesions caused by P. pseudosyringae were found across England, Scotland and Wales. Additional symptoms such as twig blight and leaf necrosis indicated that aerial infection was occurring. Besides N. obliqua, other hosts regularly encountered included Nothofagus alpina, Fagus sylvatica and Vaccinium myrtillus. In pathogenicity tests involving inoculation of logs, P. pseudosyringae was shown to be an aggressive bark pathogen of N. obliqua and F. sylvatica, but significantly less aggressive on N. alpina. Foliage susceptibility and sporulation tests showed marked differences between the six host species tested. Leaves of N. obliqua and V. myrtillus were highly susceptible. Leaves of N. alpina were moderately susceptible, those of Rhododendron ponticum slightly susceptible and those of F. sylvatica not susceptible at all. High levels of sporulation were observed only on inoculated N. obliqua and V. myrtillus leaves. This suggests that P. pseudosyringae may sporulate heavily on N. obliqua foliage in the field and that this inoculum initiates the aerial lesions observed on the shoots, branches and stems. The results also suggest that P. pseudosyringae has the potential to pose a serious threat to N. obliqua and other Nothofagus species in their Southern Hemisphere native ranges.
The Effect of Sperm Concentration and Storage Vessel on Quercetin‐Supplemented Rabbit Semen During Chilled Storage
Authors: Johinke D , de Graaf SP , Bathgate R
Published: May 2015

Contents

Extending the shelf life of chilled rabbit spermatozoa is vital for the expansion of the farmed rabbit industry. This study evaluated the relationship between sperm concentration and packaging on in vitro quality of chilled rabbit semen over 96 h. Semen was collected from adult bucks (n = 4) and pooled at 37°C following evaluation. Pooled ejaculates were diluted with a Tris‐based extender supplemented with 100 μm quercetin to a concentration of 15, 30 or 60 × 106 spermatozoa/ml, packaged into plastic tubes or 0.5‐ml straws and stored at 15°C. Sperm quality was assessed by computer‐assisted sperm Analysis [total motility (tMOT)] and flow cytometry [viability, acrosome integrity, H2O2 production, plasma membrane disorder, apoptosis and DNA fragmentation index (DFI)] at 0, 48, 72 and 96 h. From 48 h, concentrations of 30 and 60 × 106 spermatozoa/ml reported the highest tMOT, irrespective of storage vessel (p < 0.05). Storage in straws reduced oxidative stress and improved plasma membrane stability. The %DFI, mean DFI and SD‐DFI were increased in spermatozoa stored in tubes compared with straws (p < 0.05). Although the use of low sperm concentrations in artificial insemination doses would facilitate greater dispersion of genetically superior rabbit bucks, dilution to 15 × 106 spermatozoa/ml had a detrimental impact on motility. As such, chilled storage at 30 × 106 spermatozoa/ml may provide a suitable balance between motility and H2O2 production to best maintain overall sperm function and should be evaluated in a large‐scale AI trial.
Evaluation of the role of lung volume and airway size and shape in supine‐predominant obstructive sleep apnoea patients
Authors: Joosten Simon A. , Sands Scott A. , Edwards Bradley A. , Hamza Kais , Turton Anthony , Lau Kenneth K. , Crossett Marcus , Berger Philip J. , Hamilton Garun S.
Published: May 2015

Background and objective

This study aimed to evaluate the involvement of airway cross‐sectional area and shape, and functional residual capacity (FRC), in the genesis of obstructive sleep apnoea (OSA) in patients with supine‐predominant OSA.

Methods

Three groups were recruited: (i) supine OSA, defined as a supine apnoea–hyponoea index (AHI) at least twice that of the non‐supine AHI; (ii) rapid eye movement (REM) OSA, defined as REM AHI at least twice the non‐REM AHI and also selected to have supine AHI less than twice that of the non‐supine AHI (i.e. to be non‐positional); and (iii) no OSA, defined as an AHI less than five events per hour. The groups were matched for age, gender and body mass index. Patients underwent four‐dimensional computed tomography scanning of the upper airway in the supine and lateral decubitus positions. FRC was measured in the seated, supine and lateral decubitus positions.

Results

Patients with supine OSA demonstrated a significant decrease in FRC of 340 mL (P = 0.026) when moving from the lateral to supine position compared to controls with no OSA, and REM OSA patients. We found no differences between groups in upper airway size and shape. However, all groups showed a significant change in airway shape with the velopharyngeal airway adopting a more elliptoid shape (with the long axis laterally oriented), with reduced anteroposterior diameter in the supine position.

Conclusions

A fall in FRC when moving lateral to supine in supine OSA patients may be an important triggering factor in the generation of OSA in this patient group.
Reasoned Decision Making Without Math? Adaptability and Robustness in Response to Surprise
Authors: Smithson Michael , Ben‐Haim Yakov
Published: May 2015

Many real‐world planning and decision problems are far too uncertain, too variable, and too complicated to support realistic mathematical models. Nonetheless, we explain the usefulness, in these situations, of qualitative insights from mathematical decision theory. We demonstrate the integration of info‐gap robustness in decision problems in which surprise and ignorance are predominant and where personal and collective psychological factors are critical. We present practical guidelines for employing adaptable‐choice strategies as a proxy for robustness against uncertainty. These guidelines include being prepared for more surprises than we intuitively expect, retaining sufficiently many options to avoid premature closure and conflicts among preferences, and prioritizing outcomes that are steerable, whose consequences are observable, and that do not entail sunk costs, resource depletion, or high transition costs. We illustrate these concepts and guidelines with the example of the medical management of the 2003 SARS outbreak in Vietnam.
Quantifying Adversary Capabilities to Inform Defensive Resource Allocation
Authors: Wang Chen , Bier Vicki M.
Published: May 2015

We propose a Bayesian Stackelberg game capable of analyzing the joint effects of both attacker intent and capabilities on optimal defensive strategies. The novel feature of our model is the use of contest success functions from economics to capture the extent to which the success of an attack is attributable to the adversary's capability (as well as the level of defensive investment), rather than pure luck. Results of a two‐target example suggest that precise assessment of attacker intent may not be necessary if we have poor estimates of attacker capability.
Copula Gaussian graphical models with penalized ascent Monte Carlo EM algorithm
Authors: Abegaz Fentaw , Wit Ernst
Published: May 2015

Typical data that arise from surveys, experiments, and observational studies include continuous and discrete variables. In this article, we study the interdependence among a mixed (continuous, count, ordered categorical, and binary) set of variables via graphical models. We propose an ℓ1‐penalized extended rank likelihood with an ascent Monte Carlo expectation maximization approach for the copula Gaussian graphical models and establish near conditional independence relations and zero elements of a precision matrix. In particular, we focus on high‐dimensional inference where the number of observations are in the same order or less than the number of variables under consideration. To illustrate how to infer networks for mixed variables through conditional independence, we consider two datasets: one in the area of sports and the other concerning breast cancer.
Risk factors and prognostic scale for cytomegalovirus (CMV) infection in CMV‐seropositive patients after allogeneic hematopoietic cell transplantation
Authors: Cohen L. , Yeshurun M. , Shpilberg O. , Ram R.
Published: May 2015

Aim

We aimed to study the risk factors for first and subsequent cytomegalovirus (CMV) infection among patients who are CMV seropositive and underwent allogeneic hematopoietic cell transplantation (HCT).

Methods

We performed an historical cohort study of all sequential CMV‐seropositive patients who underwent allogeneic HCT at a single center. Between May 2007 and December 2012, 121 patients fulfilled inclusion criteria.

Results

Multivariate model identified myeloablative preparative regimen (hazard ratio [HR] = 4.297, P = 0.033) and acute graft‐versus‐host disease (GVHD) prior to infection (HR = 5.091, P = 0.021) as risk factors for first CMV infection. The cumulative incidences of first CMV infection for patients with 0, 1, and 2 risk factors were 52%, 71%, and 91%, respectively. Multivariate analysis identified the diagnosis of lymphoma/myeloma (HR = 3.5, P = 0.049) and GVHD (HR = 1.280, P = 0.045) as risk factors for subsequent CMV infection. High graft CD3 stem cell dose was associated with a trend of lower rate of subsequent CMV infection (HR = 0.543, P = 0.056). The cumulative incidences for subsequent CMV infection in patients with 0, 1, and 2–3 risk factors were 11%, 41%, and 77%, respectively.

Conclusion

In conclusion, in CMV‐seropositive patients, myeloablative conditioning and acute GVHD are risk factors for first CMV infection, while lymphoma/myeloma, ongoing GVHD, and low CD3 graft content are risk factors for subsequent infection.
Exact functors on perverse coherent sheaves
Authors: Koppensteiner Clemens
Published: May 2015

Inspired by symplectic geometry and a microlocal characterizations of perverse (constructible) sheaves we consider an alternative definition of perverse coherent sheaves. We show that a coherent sheaf is perverse if and only if $R{\rm\Gamma}_{Z}{\mathcal{F}}$ is concentrated in degree $0$ for special subvarieties $Z$ of $X$. These subvarieties $Z$ are analogs of Lagrangians in the symplectic case.
Conjugate Heat Transfer in Latent Heat Thermal Storage System With Cross Plate Fins
Authors: Alayil Rajesh , Balaji C.
Published: May 2015

Latent heat thermal storage systems (LHTS) utilize their latent heat capacity to dissipate high heat fluxes while maintaining quasi-isothermal conditions. Phase change materials (PCMs) absorb a large amount of energy during their phase transformation from solid to liquid, maintaining quasi-isothermal conditions. However, they are often beset with low thermal conductivities which necessitate the use of a thermal conductivity enhancer (TCE) as it is impossible to design a device that can completely avoid sensible heat in the premelting or postmelting phase. In this study, the heat transfer performance of LHTS with cross plate fins as a TCE is numerically investigated for different values of fin thicknesses and fin numbers along the length and breadth. A hybrid artificial neural network coupled genetic algorithm (ANN–GA) is then used to obtain the optimized dimensions for the composite heat sink with cross plate fins as TCE for a fixed volume and a specific heat flux input. The numerically optimized configuration is finally validated with in-house experiments.
Formability Enhancement in Titanium Tube-Flaring by Manipulating the Deformation Path
Authors: Nikhare Chetan P. , Korkolis Yannis P. , Kinsey Brad L.
Published: May 2015

The tube flaring process has been traditionally used to expand one end of a tube without changing its cross-sectional area. This simple process typically forms the product using a single punch. To delay failure and enhance formability, a two-step flaring process can be used. For example, if a significant elliptical flared shape is attempted in a one-step process, a necking/tearing failure would occur on the major axis of the ellipse. However, if a two-step process, starting with a mildly elliptical punch and followed by the final, sharply elliptical punch is used instead, the desired elliptical shape can be achieved. In this paper, the effects of the punch geometry of the first step on the deformation paths are numerically analyzed. By manipulating the deformation path, failure can be delayed so that higher formability is achieved. The numerical model is validated by comparison with experimental results.
Development of High-Speed Sleeve Bearings for a Solar 500-HP Gas Turbine Engine
Authors: Blackwood D. E. , Swatman I. M.
Published: May 2015

The potential advantages of sleeve bearings over antifriction bearings in a gas turbined engine are discussed. Description is given of the design problems, rig tests, and engine tests to date on a gas turbine adapted to use of sleeve bearings from an earlier design using antifriction bearings.
Rotary Regenerator for Gas Turbines
Authors: Miles J. C. , Parker N. A. , Smoot R. L.
Published: May 2015

Test performance of a rotary regenerator comprising the experimental evaluation of three lengths of flame-trap -type matrices is presented. Design parameters based on the experimental results are given. A compact structural design of a rotary regenerator is illustrated along with a configuration for a proposed application to small turbines. A seal design is suggested and the problem of matrix fouling is discussed.
The Comprex: A New Concept of Diesel Supercharging
Authors: Berchtold Max , Gardiner F. J.
Published: May 2015

The Comprex supercharger compresses air by direct transmission of energy from an expanding gas utilizing compression and expansion waves. The name Comprex is a contraction of Compression-Expander. Although the phenomena of nonsteady flow have been studied extensively in connection with explosions, diesel fuel injection, railway airbrakes, water hammer, safety equipment in hydraulic power stations, and so on, the use of these effects in gases is relatively new. This paper deals with the Comprex as applied to supercharging of internal-combustion engines. It explains the principle of operation, describes the design and discusses the particular operational characteristics as a supercharger for a 4-cycle diesel engine. It should be remembered that this is only one of many applications of a broad and unexploited field.
The Effect of Treated High-Vanadium Fuel on Gas Turbine Load, Efficiency, and Life
Authors: Buckland Bruce O.
Published: May 2015

Tests were run on four inter-cooled regenerative high-temperature gas turbines of like design to measure the effect of burning several different residual fuels. Some of the tests were made with the help and co-operation of the Central Vermont Public Service Corporation on two of their units at Rutland, Vermont. Other tests were made at Bangor, Maine, with the help and co-operation of The Esso Research and Engineering Company, and the Bangor Hydroelectric Company, on the two units in the Graham Station. The results of the tests can be summarized as follows:

1. After a few hundred hours of intermittent operation, the first-stage nozzle area reaches a steady-state condition wherein it oscillates between zero and a maximum of about 8 percent reduction in area due to oil ash. The maximum reduction varies from 4 percent to 8 percent, depending on the fuel;

2. With continuous operation the first-stage nozzle area does not reach a steady-state value in 100 hours but plugs more or less continuously at rates varying from 5 to 24 percent per hundred hours, depending on the fuel. The load decreases also at rates varying from one to twenty percent in the same period;

3. Increasing the magnesium content of the fuel with respect to its vanadium content increases the deposition rate, but increasing the aluminum with respect to the vanadium content has the opposite effect;

4. Substantial temperature changes due to load variations and changes of firing temperature have little or no effect on dislodging the ash, but shutdowns in excess of two hours duration cause recoveries of over 70 percent in the area and over 50 percent in the load;

5. Introducing about 15 pounds of spent refinery catalyst into the low-pressure compressor inlet results in more than 40 percent recovery in the nozzle area and about the same recovery in the load. This cleaning operation, followed by a shutdown, results in practically complete recovery in both load and area during subsequent operation.

A test was run for 2400 hours with a single residual fuel containing about 360 ppm of vanadium following 2700 hours operation on distillate fuel. Comparisons of the gas-path parts with those of two other units of the same design, one using a residual oil having 80 ppm of vanadium and the other using natural gas, lead to the following conclusions:

1. The life of the gas-path parts is no different whether a high vanadium or a low vanadium residual fuel is used;

2. The corrosion of the nozzles and buckets is not much greater with treated residual oil than with natural gas.
Economic Considerations in Applying Gas Turbines to Electric Utility and Industrial Applications
Authors: Dygert C. R.
Published: May 2015

Although there is tremendous interest in the gas turbine and it has become a fully recognized prime mover, there have been relatively little data collected in one paper which would aid in evaluating various gas turbine cycles. This paper presents estimating cost data which can be used for preliminary evaluations and discusses factors, unique with the gas turbine, which should be considered. Although well known, two of the common methods of evaluating power plants are discussed with particular reference to gas turbines.
40,000-KW Gas-Turbine Power Plant — Mayaguez, Puerto Rico
Authors: Stys Z. Stanley
Published: May 2015

Application of the gas turbine in peak-load plants appears attractive. Several units have been in this kind of operation for many years in different parts of the world. For isolated systems especially, the application of gas turbines for peaking service presents definite advantages. The background of experience as well as layout and design of such plants are described here.
Relative Thermal Performance of Carbon Dioxide and Helium in Nuclear-Power Cycles
Authors: Tippets Frank E.
Published: May 2015

Analytical comparison is made of the relative heat-transfer-area requirements of carbon dioxide and helium in nuclear-powered gas-turbine cycles and gas cooled reactor–steam turbine systems. Helium is shown to require considerably less heat-transfer area than carbon dioxide in equivalent direct gas-turbine cycles. However, conclusion as to which gas should be considered to have the better heat-transfer characteristics for use in gas cooled reactor–steam turbine systems is indefinite for it appears to depend on the basis of comparison used.
A Lightweight 8000 HP Gas Turbine for Marine Propulsion
Authors: Proscino Vincent
Published: May 2015

A fully developed turbojet engine, with minor modifications, was combined with a light-weight free-wheeling power turbine to produce a compact 8000-hp propulsion unit for naval marine service. Commercial control features were combined with aircraft components to provide a completely automatic remote control. The engine has been developed to burn diesel fuel, and has demonstrated the ability to run 500 hr at full load, indicating a normal service life of 1000 hr between overhauls.
The Past, Present and Future of a Pipeline Gas Turbine
Authors: Carameros A. H. , Mathews B. J. , Moyer W. B.
Published: May 2015

El Paso reviews its experience with the gas turbine. Requirements set forth, and how they have been fulfilled are discussed along with problems encountered with respect to design, operation, and maintenance. Desirable improvements in the gas turbine and associated equipment are also discussed.
Transient Temperatures and Thermal Stress Problems in Small Gas Turbines
Authors: van Nimwegen Robert R.
Published: May 2015

A discussion is given of the steady and transient temperature problems associated with the design of small gas turbines and starter equipment. The transient heat-conduction equation is given in differential and finite-difference form. Boundary conditions of convective heat transfer, radiation and prescribed temperatures are discussed. Several methods for solution of these equations in irregularly shaped bodies are given. Examples of solutions of typical temperature problems in small gas turbines are shown. Solution by means of an electrolytic tank, analog computer and a digital computer are discussed, with the advantages and disadvantages of each method given.
The Coal-Burning Closed-Cycle Gas Turbine
Authors: Keller C. , Gaehler W.
Published: May 2015

Since 1956, when the last report on closed-cycle gas-turbine development was presented in the U. S., six solid-fuel-fired plants, rated from 2 to 13.5-mw, have come into operation. Additional oil and gas-fired installations, both for stationary power plants and ship propulsion, have been built and operated or will soon start operation. Unfortunately, none of these are in the U. S.
A 7500-SHP Gas Turbine for Naval Boost Propulsion
Authors: Harris F. R.
Published: May 2015

The G.6 gas turbine, of 7500-shp output, forms part of the combined steam-turbine and gas-turbine propulsion machinery currently being installed in two classes of British naval ships. The design specification included some requirements of a novel nature; details are given of the mechanical construction of the gas turbine, and of its test-bed performance. The possibilities of further development are outlined.
Segregated Structures in Highly Alloyed Ferritic Gas-Turbine Wheel Forgings
Authors: Heckman G. R. , Herbenar A. W.
Published: May 2015

Segregates present in highly alloyed materials, particularly in modified 12 per cent Cr steels, can have very adverse effects on the physical and mechanical properties. It has been shown that such inhomogeneities can act as inherent notches or stress risers which contribute to or cause premature failures. The fact that such segregation cannot be detected by nondestructive magnetic-particle or sonic tests dictates the use of alternate inspection and process methods to qualify highly stressed parts, such as turbine wheels, for actual service. Turbine wheels, especially those of high-alloy content, produced in accordance with inspection procedures and process methods described herein can be assured to give reliable and satisfactory service.
El Paso Uprates Two Gas Turbines
Authors: Uhr J. I. , Matthews B. J.
Published: May 2015

El Paso discusses the philosophy of uprating older gas turbines by taking advantage of the continuous progress being made in turbine design. This paper describes El Paso’s uprating of two General Electric gas turbines and includes the feasibility study, modificaton required and operating experience.
High-Speed Rotor Suspension Formed by Fully Floating Hydrodynamic Radial and Thrust Bearings
Authors: Dworski Juraj
Published: May 2015

The hydrodynamic suspension of a 44,000-rpm gas-turbine rotor is described with emphasis on interaction between the flexible rotor and its supports. Bearings with relatively large clearances are shown to allow continuous operation at the rotor first critical speed of 22,000 rpm. The apparent absence of hydrodynamic system instabilities is attributed to the use of simple floating-sleeve bearings. A parametric study of the influence of bearing clearances upon vibrational excitation relief is presented together with test data collected on actual system hardware.
Gas-Turbine Application in U. S. Coast Guard Vessels
Authors: Case Robert C. , Logan James M.
Published: May 2015

This paper is a summarization of the application of gas turbines for Coast Guard shipboard use. Included are discussions of turbine applications in present use and their results, vessels presently being built which will employ gas turbines, and possible future applications of gas turbines both for main and auxiliary power aboard Coast Guard vessels. Comparisons of gas turbines with other power sources as to weight, space, fuel consumption and economy are included for the presently known applications.
What to do About Gas-Turbine Noise
Authors: McAuliffe D. R. , Morlock H. , Oran F. M.
Published: May 2015

A brief review is made of the various applications for the gas turbine. A discussion is presented which indicates the cause of the intake and exhaust noise. Equations are given which will allow calculations of the noise for a large range of gas-turbine-engine sizes. Other acoustical data are presented which provide the design engineer with a method to evaluate specific gas-turbine noise problems. General information is given on the selection of silencers and enclosures for reduction of noise to appropriate design goals. A typical example of a gas-turbine noise problem is detailed.