202 research outputs found
Throughput Benefit Assessment for Tactical Runway Configuration Management (TRCM)
The System-Oriented Runway Management (SORM) concept is a collection of needed capabilities focused on a more efficient use of runways while considering all of the factors that affect runway use. Tactical Runway Configuration Management (TRCM), one of the SORM capabilities, provides runway configuration and runway usage recommendations, monitoring the active runway configuration for suitability given existing factors, based on a 90 minute planning horizon. This study evaluates the throughput benefits using a representative sample of today's traffic volumes at three airports: Memphis International Airport (MEM), Dallas-Fort Worth International Airport (DFW), and John F. Kennedy International Airport (JFK). Based on this initial assessment, there are statistical throughput benefits for both arrivals and departures at MEM with an average of 4% for arrivals, and 6% for departures. For DFW, there is a statistical benefit for arrivals with an average of 3%. Although there is an average of 1% benefit observed for departures, it is not statistically significant. For JFK, there is a 12% benefit for arrivals, but a 2% penalty for departures. The results obtained are for current traffic volumes and should show greater benefit for increased future demand. This paper also proposes some potential TRCM algorithm improvements for future research. A continued research plan is being worked to implement these improvements and to re-assess the throughput benefit for today and future projected traffic volumes
Benefits Assessment for Tactical Runway Configuration Management Tool
The Tactical Runway Configuration Management (TRCM) software tool was developed to provide air traffic flow managers and supervisors with recommendations for airport configuration changes and runway usage. The objective for this study is to conduct a benefits assessment at Memphis (MEM), Dallas Fort-Worth (DFW) and New York's John F. Kennedy (JFK) airports using the TRCM tool. Results from simulations using the TRCM-generated runway configuration schedule are compared with results using historical schedules. For the 12 days of data used in this analysis, the transit time (arrival fix to spot on airport movement area for arrivals, or spot to departure fix for departures) for MEM departures is greater (7%) than for arrivals (3%); for JFK, there is a benefit for arrivals (9%) but not for departures (-2%); for DFW, arrivals show a slight benefit (1%), but this is offset by departures (-2%). Departure queue length benefits show fewer aircraft in queue for JFK (29%) and MEM (11%), but not for DFW (-13%). Fuel savings for surface operations at MEM are seen for both arrivals and departures. At JFK there are fuel savings for arrivals, but these are offset by increased fuel use for departures. In this study, no surface fuel benefits resulted for DFW. Results suggest that the TRCM algorithm requires modifications for complex surface traffic operations that can cause taxi delays. For all three airports, the average number of changes in flow direction (runway configuration) recommended by TRCM was many times greater than the historical data; TRCM would need to be adapted to a particular airport's needs, to limit the number of changes to acceptable levels. The results from this analysis indicate the TRCM tool can provide benefits at some high-capacity airports. The magnitude of these benefits depends on many airport-specific factors and would require adaptation of the TRCM tool; a detailed assessment is needed prior to determining suitability for a particular airport
Found in Translation: Essays on Biblical Jewish Translation in Honor of Leonard J. Greenspoon
Found in Translation is at once a themed volume on the translation of ancient Jewish texts and a Festschrift for Leonard J. Greenspoon, the Philip M. and Ethel Klutznick Professor in Jewish Civilization and professor of classical and near Eastern studies and of theology at Creighton University in Omaha, Nebraska. Greenspoon has made significant contributions to the study of Jewish biblical translations, particularly the ancient translation of the Hebrew Bible into Greek, known as the Septuagint. This volume comprises an internationally renowned group of scholars presenting a wide range of original essays on Bible translation, the influence of culture on biblical translation, Bible translations’ reciprocal influence on culture, and the translation of various Jewish texts and collections, especially the Septuagint. Volume editors have painstakingly planned Found in Translation to have the broadest scope of any current work on Jewish biblical translation to reflect Greenspoon’s broad impact on the field throughout an august career.https://docs.lib.purdue.edu/purduepress_previews/1009/thumbnail.jp
Proton pump inhibitors are associated with increased risk of development of chronic kidney disease
Background Acute interstitial nephritis secondary to proton pump inhibitors (PPIs) frequently goes undiagnosed due to its subacute clinical presentation, which may later present as chronic kidney disease (CKD). We investigated the association of PPI use with the development of CKD and death. Methods Two separate retrospective case–control study designs were employed with a prospective logistic regression analysis of data to evaluate the association of development of CKD and death with PPI use. The population included 99,269 patients who were seen in primary care VISN2 clinics from 4/2001 until 4/2008. For evaluation of the CKD outcome, 22,807 with preexisting CKD at the first observation in Veterans Affairs Health Care Upstate New York (VISN2) network data system were excluded. Data obtained included use of PPI (Yes/No), demographics, laboratory data, pre-PPI comorbidity variables. Results A total of 19,311/76,462 patients developed CKD. Of those who developed CKD 24.4 % were on PPI. Patients receiving PPI were less likely to have vascular disease, COPD, cancer and diabetes. Of the total of 99,269 patients analyzed for mortality outcome, 11,758 died. A prospective logistic analysis of case–control data showed higher odds for development of CKD (OR 1.10 95 % CI 1.05–1.16) and mortality (OR 1.76, 95 % CI 1.67–1.84) among patients taking PPIs versus those not on PPIs. Conclusions Use of proton pump inhibitors is associated with increased risk of development of CKD and death. With the large number of patients being treated with proton pump inhibitors, healthcare providers need to be better educated about the potential side effects of these medications
Benefit Assessment for Metroplex Tactical Runway Configuration Management (mTRCM) in a Simulated Environment
The System-Oriented Runway Management (SORM) concept is a collection of capabilities focused on a more efficient use of runways while considering all of the factors that affect runway use. Tactical Runway Configuration Management (TRCM), one of the SORM capabilities, provides runway configuration and runway usage recommendations, and monitoring the active runway configuration for suitability given existing factors. This report focuses on the metroplex environment, with two or more proximate airports having arrival and departure operations that are highly interdependent. The myriad of factors that affect metroplex opeations require consideration in arriving at runway configurations that collectively best serve the system as a whole. To assess the metroplex TRCM (mTRCM) benefit, the performance metrics must be compared with the actual historical operations. The historical configuration schedules can be viewed as the schedules produced by subject matter experts (SMEs), and therefore are referred to as the SMEs' schedules. These schedules were obtained from the FAA's Aviation System Performance Metrics (ASPM) database; this is the most representative information regarding runway configuration selection by SMEs. This report focused on a benefit assessment of total delay, transit time, and throughput efficiency (TE) benefits using the mTRCM algorithm at representative volumes for today's traffic at the New York metroplex (N90)
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Increased prevalence of metabolic syndrome in Veterans with PTSD untreated with antipsychotic medications
Post-Traumatic Stress Disorder (PTSD) is not solely a psychiatric disorder; it also includes significant medical morbidity. Although there is evidence of increased risk of metabolic syndrome (MetS) in PTSD, the interpretation of previous studies is confounded by inclusion of people on antipsychotic medications, which independently cause increased MetS. In this study we investigated whether Veterans with PTSD not treated with antipsychotic medications (n=115) demonstrate increased MetS compared to an age-comparable group of people from the U.S. National Health and Nutrition Examination Survey (NHNES; n=1005). Using standardized criteria (abnormal values in 3 out of the 5 domains of obesity, hypertension, high density lipoprotein, triglyceride and fasting glucose concentrations) we compared the prevalence of MetS across groups. Relative to the NHNES group, a significantly higher proportion of the Veteran PTSD group met criteria for MetS (26.9% vs. 41.7%) with a higher proportion of abnormal values in four out of five MetS domains (excepting glucose). Our results suggest that the elevation of MetS associated with PTSD cannot be fully explained by iatrogenic effects of antipsychotic medication. We suggest that extra attention be devoted to the clinical management of metabolic risk factors for morbidity in patients with PTSD
Spectral Simplicity of Apparent Complexity, Part I: The Nondiagonalizable Metadynamics of Prediction
Virtually all questions that one can ask about the behavioral and structural
complexity of a stochastic process reduce to a linear algebraic framing of a
time evolution governed by an appropriate hidden-Markov process generator. Each
type of question---correlation, predictability, predictive cost, observer
synchronization, and the like---induces a distinct generator class. Answers are
then functions of the class-appropriate transition dynamic. Unfortunately,
these dynamics are generically nonnormal, nondiagonalizable, singular, and so
on. Tractably analyzing these dynamics relies on adapting the recently
introduced meromorphic functional calculus, which specifies the spectral
decomposition of functions of nondiagonalizable linear operators, even when the
function poles and zeros coincide with the operator's spectrum. Along the way,
we establish special properties of the projection operators that demonstrate
how they capture the organization of subprocesses within a complex system.
Circumventing the spurious infinities of alternative calculi, this leads in the
sequel, Part II, to the first closed-form expressions for complexity measures,
couched either in terms of the Drazin inverse (negative-one power of a singular
operator) or the eigenvalues and projection operators of the appropriate
transition dynamic.Comment: 24 pages, 3 figures, 4 tables; current version always at
http://csc.ucdavis.edu/~cmg/compmech/pubs/sdscpt1.ht
In-roads to the spread of antibiotic resistance: regional patterns of microbial transmission in northern coastal Ecuador
The evolution of antibiotic resistance (AR) increases treatment cost and probability of failure, threatening human health worldwide. The relative importance of individual antibiotic use, environmental transmission and rates of introduction of resistant bacteria in explaining community AR patterns is poorly understood. Evaluating their relative importance requires studying a region where they vary. The construction of a new road in a previously roadless area of northern coastal Ecuador provides a valuable natural experiment to study how changes in the social and natural environment affect the epidemiology of resistant Escherichia coli. We conducted seven bi-annual 15 day surveys of AR between 2003 and 2008 in 21 villages. Resistance to both ampicillin and sulphamethoxazole was the most frequently observed profile, based on antibiogram tests of seven antibiotics from 2210 samples. The prevalence of enteric bacteria with this resistance pair in the less remote communities was 80 per cent higher than in more remote communities (OR = 1.8 [1.3, 2.3]). This pattern could not be explained with data on individual antibiotic use. We used a transmission model to help explain this observed discrepancy. The model analysis suggests that both transmission and the rate of introduction of resistant bacteria into communities may contribute to the observed regional scale AR patterns, and that village-level antibiotic use rate determines which of these two factors predominate. While usually conceived as a main effect on individual risk, antibiotic use rate is revealed in this analysis as an effect modifier with regard to community-level risk of resistance
The Roles of Standardization, Certification and Assurance Services in Global Commerce
In this article we examine the rapid emergence and expansion of standardized product and process frameworks and a private-sector compliance and enforcement infrastructure that we believe may increasingly be providing a substitute for public and legal regulatory infrastructure in global commerce. This infrastructure is provided by a proliferation of performance codes and standards, many of which define acceptable social and environmental behavior, and a rapidly-growing number of privately-trained and authorized inspectors and certifiers that we call the third-party assurance industry. We offer reasons for this development, evidence of its scope and scale, and then describe the phenomenon in more detail by examining supply chain arrangements in two industries, food products and apparel, where the use of third-party standards and assurance services has expanded especially rapidly. We conclude with a discussion of the implications for the make or buy decision at the core of the theory of the firm. We argue that as quasi-regulatory standards are developed within various industries, and as performance to these standards can be systematically evaluated using third-party inspectors and certifiers, the costs of moving production outside of vertical firm hierarchies drop. We believe this may be an important factor in accelerating the shift to outsourcing that has been observed over the last two decades
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