Experimental test of airplane boarding methods

We report the results of an experimental comparison of different airplane boarding methods. This test was conducted in a mock 757 fuselage, located on a Southern California soundstage, with 12 rows of six seats and a single aisle. Five methods were tested using 72 passengers of various ages. We found a significant reduction in the boarding times of optimized methods over traditional methods. These improved methods, if properly implemented, could result in a significant savings to airline companies.Comment: 8 pages, submitted to the Journal of Air Transport Managemen

Management of the Hydrologic System in Areas Subject to Coal Mining Activities

Publicity given to the detrimental effects of mining activities on the environment has tended to overshadow somewhat the hydrologic opportunities and benfits that could be associated with these activities. For example, many areas disturbed by surface mining have proved to be excellent recharge areas for groundwater aquifers. The degree to which mine sites can be exploited to improve management of the hydrologic system depends on both the local geology and the mining techniques used. The report examines the effects of present mining activities on the associated hydrology system, and identifies specific mining procedures and management techniques which not only minimize negative hydrologic impacts of mining operations, but which also enhance the values of the hydrologic system in terms of existing and potential social uses. Thus, the results of the research contribute to the solution of present and future hydrologic problems (both quanitty and quality) associated with coal mining in the western U.S. Emphasis is placed on sites which are representative of both existing and future coal mining areas. The specific objectives of the study are to: 1. Evaluate the potential for using underground coal mines to: a. Tap previously inaccessible groundwater supplies. b. Reduce the salt load to the Colorado River by decreasing the contact of groundwater with salt-bearing geologic formations. c. Store water in abondoned mines. 2. Consider the potential effects of underground coal mines on water resources. 3. Evaluate the potential of using surface mined areas to collect surface runoffs and thus: a. Reduce the sediment loads to the Colorado River. b. Enhance water storage in the basin. Each of the preceding objectives is addressed and discussed by the report in terms of actual coal mines in central Utah. The study suggests not only ways of reducing negative hydrologic impacts of mining operations, but also operational and management mining techniques which will enhance the social use value of the hydrologic systems, and thus, in fact, create hydrologic opportunities

Health services utilization and out-of-pocket (OOP) expenditures in public and private facilities in Pakistan: An empirical analysis of the 2013-14 OOP health expenditure survey

Background: As low- and middle-income countries progress toward Universal Health Coverage, there is an increasing focus on measuring out-of-pocket (OOP) expenditure and health services utilization within countries. While there have been several reforms to improve health services coverage and financial protection in Pakistan, there is limited empirical research comparing OOP expenditure and health services utilization between public and private facilities and exploring their determinants, a knowledge gap addressed in this study.Methods: We used data from 2013 to 14 OOP Health Expenditure Survey, a population-based household survey carried out for Pakistan\u27s National Health Accounts. The analysis included 7969 encounters from 4293 households. We conducted bivariate analyses to describe patterns of care utilization, estimated annualized expenditures by type and sector of care, and assessed expenditure composition. We used multivariable logistic regression modeling to identify factors associated with sector of care and generalized linear model (GLM) with log link and gamma distribution to identify determinants of OOP expenditures stratified by type of care (inpatient and outpatient).Results: Most encounters (82.5%) were in the private sector and were for outpatient visits (85%). Several public-private differences were observed in annualized expenditures and expenditure components. Logistic regression results indicate males, wealthier individuals, Punjab and Sindh residents, and those in smaller households were more likely to access private outpatient care. In the inpatient model, rural residents were more likely to use a private provider, while Khyber Pakhtunkhwa residents were less likely to use private care. GLM results indicate private sector inpatient expenditures were approximately PKR 6660 (USD 61.8) higher than public sector expenditures, but no public-private differences were observed for outpatient expenditures. Several demographic factors were significantly associated with outpatient and inpatient expenditures. Of note, expenditures increased with increasing wealth, decreased with increasing household size, and differed by province and region.Conclusions: This is the first study comprehensively investigating how healthcare utilization and OOP expenditures vary by sector, type of care, and socio-economic characteristics in Pakistan. The findings are expected to be particularly useful for the next phase of social health protection programs and supply side reforms, as they highlight sub-populations with higher OOP and private sector utilization

Formation of Bis(hydroxyalkyl)N-nitrosamines as products of the nitrosation of spermidine

The purpose of this study was to characterize the nonvolatile, water soluble, bis(hydroxyalkyl)N-nitrosamines produced from the reaction of spermidine and nitrite. The biologically occurring polyamine spermidine was reacted with nitrite in the presence of acid. The reaction products were isolated and converted to trimethylsilyl (TMS) derivatives. The derivatized products were separated by gas-liquid chromatography using an all glass, wall coated, capillary column. Mass spectral data were collected on the chromatographic effluent. Four isomers of bis(hydroxyalkyl)N-nitrosamine were synthesized by combining the appropriate aminopropanol with the appropriate chlorobutanol. Infrared, nuclear magnetic resonance, mass spectral, and thin-layer chromatographic data were collected on the synthetic compounds to assure their structure. Kovat's indices were collected on the TMS derivative of each authentic compound and compared to the retention data collected on the TMS derivatives of the reaction products of spermidine and nitrite. A comparison of the mass spectra of the TMS derivatives of the authentic compounds to the spectra of the reaction products having the same retention time allowed structural assignments to four compounds. The compounds identified, in order of decreasing amounts were: 4-hydroxybutyl(3-hydroxypropyl)N-nitrosamine, 3-hydroxybutyl(3-hydroxypropyl)N-nitrosamine, 4-hydroxybutyl(2- hydroxypropylJN-nitrosamine, and 3-hydroxybutyl(2-hydroxypropyl)N-nitrosamine

Dissolved organic carbon uptake in streams: A review and assessment of reach‐scale measurements

Quantifying the role that freshwater ecosystems play in the global carbon cycle requires accurate measurement and scaling of dissolved organic carbon (DOC) removal in river networks. We reviewed reach‐scale measurements of DOC uptake from experimental additions of simple organic compounds or leachates to inform development of aquatic DOC models that operate at the river network, regional, or continental scale. Median DOC uptake velocity (vf) across all measurements was 2.28 mm min−1. Measurements using simple compound additions resulted in faster vf (2.94 mm min−1) than additions of leachates (1.11 mm min−1). We also reviewed published data of DOC bioavailability for ambient stream water and leaf leachate DOC from laboratory experiments. We used these data to calculate and apply a correction factor to leaf leachate uptake velocity to estimate ambient stream water DOC uptake rates at the reach scale. Using this approach, we estimated a median ambient stream DOC vf of 0.26 mm min−1. Applying these DOC vf values (0.26, 1.11, 2.28, and 2.94 mm min−1) in a river network inverse model in seven watersheds revealed that our estimated ambient DOC vf value is plausible at the network scale and 27 to 45% of DOC input was removed. Applying the median measured simple compound or leachate vf in whole river networks would require unjustifiably high terrestrial DOC inputs to match observed DOC concentrations at the basin mouth. To improve the understanding and importance of DOC uptake in fluvial systems, we recommend using a multiscale approach coupling laboratory assays, with reach‐scale measurements, and modeling

Trends in adult cardiovascular disease risk factors and their socio-economic patterning in the Scottish population 1995–2008: cross-sectional surveys

<p>Objectives To examine secular and socio-economic changes in cardiovascular disease risk factor prevalences in the Scottish population. This could contribute to a better understanding of why the decline in coronary heart disease mortality in Scotland has recently stalled along with a widening of socio-economic inequalities.</p> <p>Design Four Scottish Health Surveys 1995, 1998, 2003 and 2008 (6190, 6656, 5497 and 4202 respondents, respectively, aged 25–64 years) were used to examine gender-stratified, age-standardised prevalences of smoking, alcohol consumption, physical activity, fruit and vegetable consumption, discretionary salt use and self-reported diabetes or hypertension. Prevalences were determined according to education and social class. Inequalities were assessed using the slope index of inequality, and time trends were determined using linear regression.</p> <p>Results There were moderate secular declines in the prevalence of smoking, excess alcohol consumption and physical inactivity. Smoking prevalence declined between 1995 and 2008 from 33.4% (95% CI 31.8% to 35.0%) to 29.9% (27.9% to 31.8%) for men and from 36.1% (34.5% to 37.8%) to 27.4% (25.5% to 29.3%) for women. Adverse trends in prevalence were noted for self-reported diabetes and hypertension. Over the four surveys, the diabetes prevalence increased from 1.9% (1.4% to 2.4%) to 3.6% (2.8% to 4.4%) for men and from 1.7% (1.2% to 2.1%) to 3.0% (2.3% to 3.7%) for women. Socio-economic inequalities were evident for almost all risk factors, irrespective of the measure used. These social gradients appeared to be maintained over the four surveys. An exception was self-reported diabetes where, although inequalities were small, the gradient increased over time. Alcohol consumption was unique in consistently showing an inverse gradient, especially for women.</p> <p>Conclusions There has been only a moderate decline in behavioural cardiovascular risk factor prevalences since 1995, with increases in self-reported diabetes and hypertension. Adverse socio-economic gradients have remained unchanged. These findings could help explain the recent stagnation in coronary heart disease mortalities and persistence of related inequalities.</p&gt

Employment Testing and Incentives to Learn

Employment tests predict job performance because they measure or are correlated with a large set of malleable developed abilities which are causally related to productivity. Our economy currently under-rewards the achievements that are measured by these tests. Consequently, economic incentives to study hard in high school are minimal and this absence of incentives has contributed to the low levels of achievement in math and science. The paper concludes with a discussion of ways in which employment tests can strengthen incentives to learn

Inflection point inflation: WMAP constraints and a solution to the fine-tuning problem

We consider observational constraints and fine-tuning issues in a renormalizable model of inflection point inflation, with two independent parameters. We derive constraints on the parameter space of this model arising from the WMAP 7-year power spectrum. It has previously been shown that it is possible to successfully embed this potential in the MSSM. Unfortunately, to do this requires severe fine-tuning. We address this issue by introducing a hybrid field to dynamically uplift the potential with a subsequent smooth phase transition to end inflation at the necessary point. Large parameter regions exist where this drastically reduces the fine-tuning required without ruining the viability of the model. A side effect of this mechanism is that it increases the width of the slow-roll region of the potential, thus also alleviating the problem of the fine-tuning of initial conditions. The MSSM embedding we study has been previously shown to be able to explain the smallness of the neutrino masses. The hybrid transition does not spoil this feature as there exist parameter regions where the fine-tuning parameter is as large as $10^{-1}$ and the neutrino masses remain small.Comment: 12 pages, 2 figures, JCAP style. Version accepted for publication in JCAP. Modifications made to improve readability, as requested by the referee; results and conclusions unchanged. References update