Predictive factors of difficulty in lower third molar extraction: A prospective cohort study

PubMed Central

Alvira-González, Joaquín; Valmaseda-Castellón, Eduard; Quesada-Gómez, Carmen; Gay-Escoda, Cosme

2017-01-01

Background Several publications have measured the difficulty of third molar removal, trying to establish the main risk factors, however several important preoperative and intraoperative variables are overlooked. Material and Methods A prospective cohort study comprising a total of 130 consecutive lower third molar extractions was performed. The outcome variables used to measure the difficulty of the extraction were operation time and a 100mm visual analogue scale filled by the surgeon at the end of the surgical procedure. The predictors were divided into 4 different groups (demographic, anatomic, radiographic and operative variables). A descriptive, bivariate and multivariate analysis of the data was performed. Results Patients’ weight, the presence of bulbous roots, the need to perform crown and root sectioning of the lower third molar and Pell and Gregory 123 classification significantly influenced both outcome variables (p< 0.05). Conclusions Certain anatomical, radiological and operative variables appear to be important factors in the assessment of surgical difficulty in the extraction of lower third molars. Key words:Third molar, surgical extraction, surgical difficulty. PMID:27918736

Does the poleward boundary current off Western Australia exert a dominant influence on coastal chaetognaths and siphonophores?

NASA Astrophysics Data System (ADS)

Gaughan, D. J.; Pearce, A. F.; Lewis, P. D.

2009-08-01

A transect that extended 40 km offshore across the continental shelf off Perth, Western Australia, was sampled monthly during 1997 and 1998. Zooplankton was sampled at 5 km intervals with a 300 micron-mesh bongo net deployed vertically to within 3 m of the bottom, or to a maximum depth of 70 m. Numbers of species of chaetognaths and siphonores were quantified, as were abundances of the common species from these groups and of the hydromedusae Auglaura hemistoma. The potential influences of four environmental variables (sea-level, sea surface temperature, salinity and chlorophyll concentration) on variability in diversity and abundance were assessed using generalized additive modeling. A combination of factors were found to influence the seasonal and spatial biological variability and, of these factors, non-linear relationships always contributed to the best fitting models. In all but one case, each of the environmental variables was included in the final model. The seasonally variable Leeuwin Current, whose strength is measured as variations in local sea-level, is the dominant mesoscale oceanographic feature in the study region but was not found to have an overriding influence on the shelf zooplankton. This contrasts a previous hypothesis that subjectively attributed seasonal variability of the same taxa examined in this study to seasonal variations in the Leeuwin Current. There remains a poor understanding of shelf zooplankton off Western Australia and, in particular, of the processes that influence seasonal and spatial variability. A more complete understanding of potential causative influences of the Leeuwin Current on the shelf plankton community of south-western Australia must be cognizant of a range of biophysical factors operating at both the broader mesoscale and at smaller scales within the shelf pelagic ecosystem.

The relationship between operative and radiographic acetabular component orientation: which factors influence resultant cup orientation?

PubMed

Grammatopoulos, G; Pandit, H G; da Assunção, R; McLardy-Smith, P; De Smet, K A; Gill, H S; Murray, D W

2014-10-01

There is great variability in acetabular component orientation following hip replacement. The aims of this study were to compare the component orientation at impaction with the orientation measured on post-operative radiographs and identify factors that influence the difference between the two. A total of 67 hip replacements (52 total hip replacements and 15 hip resurfacings) were prospectively studied. Intra-operatively, the orientation of the acetabular component after impaction relative to the operating table was measured using a validated stereo-photogrammetry protocol. Post-operatively, the radiographic orientation was measured; the mean inclination/anteversion was 43° (sd 6°)/ 19° (sd 7°). A simulated radiographic orientation was calculated based on how the orientation would have appeared had an on-table radiograph been taken intra-operatively. The mean difference between radiographic and intra-operative inclination/anteversion was 5° (sd 5°)/ -8° (sd 8°). The mean difference between simulated radiographic and intra-operative inclination/anteversion, which quantifies the effect of the different way acetabular orientation is measured, was 3°/-6° (sd 2°). The mean difference between radiographic and simulated radiographic orientation inclination/anteversion, which is a manifestation of the change in pelvic position between component impaction and radiograph, was 1°/-2° (sd 7°). This study demonstrated that in order to achieve a specific radiographic orientation target, surgeons should implant the acetabular component 5° less inclined and 8° more anteverted than their target. Great variability (2 sd about ± 15°) in the post-operative radiographic cup orientation was seen. The two equally contributing causes for this are variability in the orientation at which the cup is implanted, and the change in pelvic position between impaction and post-operative radiograph. ©2014 The British Editorial Society of Bone & Joint Surgery.

Key performance indicators for electric mining shovels and oil sands diggability

NASA Astrophysics Data System (ADS)

Patnayak, Sibabrata

A shovel performance monitoring study was undertaken in two oil sands mines operated by Syncrude Canada Ltd. using performance data obtained from P&H 4100 TS and BOSS electric mining shovels. One year of shovel performance data along with geological, geotechnical, and climatic data were analyzed. The approach adopted was to use current and voltage data collected from hoist and crowd motors and to calculate the energy and/or power associated with digging. Analysis of performance data along with digital video records of operating shovels indicated that hoist and crowd motor voltages and currents can be used to identify the beginning and the end of individual dig cycles. A dig cycle identification algorithm was developed. Performance indicators such as dig cycle time, hoist motor energy and power, and crowd motor energy and power were determined. The shovel performance indicators provide important insight into how geology, equipment and operators affect the digging efficiency. The hoist motor power is a useful key performance indicator for assessing diggability. Hoist motor energy consumption per tonne of material excavated and the number of dig cycles required for loading a truck can be useful key performance indicators for assessing operator performance and productivity. Analysis of performance data along with operators team schedules showed that the performance of a shovel can be significantly influenced by the operator's digging technique while digging uniform material. Up to 25% variability in hoist motor power consumption and 50% variability in productivity was noted between different operators. Shovel type and dipper teeth configuration can also influence the power draw on electrical motors during digging. There is no common agreement existing on the influence of bitumen content on oil sands diggability. By comparing the hoist motor power consumption, it was found that the rich ore was more difficult to dig than the lean ore. Similarly, estuarine ore was more difficult to dig than marine ore. Winter weather was expected to have a significant influence on oil sands diggability but was found to have only a minor and localized influence that depends upon the ore type, temperature conditions and the duration of bench exposure.

Increasing work-time influence: consequences for flexibility, variability, regularity and predictability.

PubMed

Nabe-Nielsen, Kirsten; Garde, Anne Helene; Aust, Birgit; Diderichsen, Finn

2012-01-01

This quasi-experimental study investigated how an intervention aiming at increasing eldercare workers' influence on their working hours affected the flexibility, variability, regularity and predictability of the working hours. We used baseline (n = 296) and follow-up (n = 274) questionnaire data and interviews with intervention-group participants (n = 32). The work units in the intervention group designed their own intervention comprising either implementation of computerised self-scheduling (subgroup A), collection of information about the employees' work-time preferences by questionnaires (subgroup B), or discussion of working hours (subgroup C). Only computerised self-scheduling changed the working hours and the way they were planned. These changes implied more flexible but less regular working hours and an experience of less predictability and less continuity in the care of clients and in the co-operation with colleagues. In subgroup B and C, the participants ended up discussing the potential consequences of more work-time influence without actually implementing any changes. Employee work-time influence may buffer the adverse effects of shift work. However, our intervention study suggested that while increasing the individual flexibility, increasing work-time influence may also result in decreased regularity of the working hours and less continuity in the care of clients and co-operation with colleagues.

Breaking the trade-off between efficiency and service.

PubMed

Frei, Frances X

2006-11-01

For manufacturers, customers are the open wallets at the end of the supply chain. But for most service businesses, they are key inputs to the production process. Customers introduce tremendous variability to that process, but they also complain about any lack of consistency and don't care about the company's profit agenda. Managing customer-introduced variability, the author argues, is a central challenge for service companies. The first step is to diagnose which type of variability is causing mischief: Customers may arrive at different times, request different kinds of service, possess different capabilities, make varying degrees of effort, and have different personal preferences. Should companies accommodate variability or reduce it? Accommodation often involves asking employees to compensate for the variations among customers--a potentially costly solution. Reduction often means offering a limited menu of options, which may drive customers away. Some companies have learned to deal with customer-introduced variability without damaging either their operating environments or customers' service experiences. Starbucks, for example, handles capability variability among its customers by teaching them the correct ordering protocol. Dell deals with arrival and request variability in its high-end server business by outsourcing customer service while staying in close touch with customers to discuss their needs and assess their experiences with third-party providers. The effective management of variability often requires a company to influence customers' behavior. Managers attempting that kind of intervention can follow a three-step process: diagnosing the behavioral problem, designing an operating role for customers that creates new value for both parties, and testing and refining approaches for influencing behavior.

Influences of operational parameters on phosphorus removal in batch and continuous electrocoagulation process performance.

PubMed

Nguyen, Dinh Duc; Yoon, Yong Soo; Bui, Xuan Thanh; Kim, Sung Su; Chang, Soon Woong; Guo, Wenshan; Ngo, Huu Hao

2017-11-01

Performance of an electrocoagulation (EC) process in batch and continuous operating modes was thoroughly investigated and evaluated for enhancing wastewater phosphorus removal under various operating conditions, individually or combined with initial phosphorus concentration, wastewater conductivity, current density, and electrolysis times. The results revealed excellent phosphorus removal (72.7-100%) for both processes within 3-6 min of electrolysis, with relatively low energy requirements, i.e., less than 0.5 kWh/m 3 for treated wastewater. However, the removal efficiency of phosphorus in the continuous EC operation mode was better than that in batch mode within the scope of the study. Additionally, the rate and efficiency of phosphorus removal strongly depended on operational parameters, including wastewater conductivity, initial phosphorus concentration, current density, and electrolysis time. Based on experimental data, statistical model verification of the response surface methodology (RSM) (multiple factor optimization) was also established to provide further insights and accurately describe the interactive relationship between the process variables, thus optimizing the EC process performance. The EC process using iron electrodes is promising for improving wastewater phosphorus removal efficiency, and RSM can be a sustainable tool for predicting the performance of the EC process and explaining the influence of the process variables.

Diagnosis and Prognostic of Wastewater Treatment System Based on Bayesian Network

NASA Astrophysics Data System (ADS)

Li, Dan; Yang, Haizhen; Liang, XiaoFeng

2010-11-01

Wastewater treatment is a complicated and dynamic process. The treatment effect can be influenced by many variables in microbial, chemical and physical aspects. These variables are always uncertain. Due to the complex biological reaction mechanisms, the highly time-varying and multivariable aspects, the diagnosis and prognostic of wastewater treatment system are still difficult in practice. Bayesian network (BN) is one of the best methods for dealing with uncertainty in the artificial intelligence field. Because of the powerful inference ability and convenient decision mechanism, BN can be employed into the model description and influencing factor analysis of wastewater treatment system with great flexibility and applicability.In this paper, taking modified sequencing batch reactor (MSBR) as an analysis object, BN model was constructed according to the influent water quality, operational condition and effluent effect data of MSBR, and then a novel approach based on BN is proposed to analyze the influencing factors of the wastewater treatment system. The approach presented gives an effective tool for diagnosing and predicting analysis of the wastewater treatment system. On the basis of the influent water quality and operational condition, effluent effect can be predicted. Moreover, according to the effluent effect, the influent water quality and operational condition also can be deduced.

Presence Relates to Distinct Outcomes in Two Virtual Environments Employing Different Learning Modalities

PubMed Central

Persky, Susan; Kaphingst, Kimberly A.; McCall, Cade; Lachance, Christina; Beall, Andrew C.; Blascovich, Jim

2009-01-01

Presence in virtual learning environments (VLEs) has been associated with a number of outcome factors related to a user’s ability and motivation to learn. The extant but relatively small body of research suggests that a high level of presence is related to better performance on learning outcomes in VLEs. Different configurations of form and content variables such as those associated with active (self-driven, interactive activities) versus didactic (reading or lecture) learning may, however, influence how presence operates and on what content it operates. We compared the influence of presence between two types of immersive VLEs (i.e., active versus didactic techniques) on comprehension and engagement-related outcomes. The findings revealed that the active VLE promoted greater presence. Although we found no relationship between presence and learning comprehension outcomes for either virtual environment, presence was related to information engagement variables in the didactic immersive VLE but not the active environment. Results demonstrate that presence is not uniformly elicited or effective across immersive VLEs. Educational delivery mode and environment complexity may influence the impact of presence on engagement. PMID:19366319

Presence relates to distinct outcomes in two virtual environments employing different learning modalities.

PubMed

Persky, Susan; Kaphingst, Kimberly A; McCall, Cade; Lachance, Christina; Beall, Andrew C; Blascovich, Jim

2009-06-01

Presence in virtual learning environments (VLEs) has been associated with a number of outcome factors related to a user's ability and motivation to learn. The extant but relatively small body of research suggests that a high level of presence is related to better performance on learning outcomes in VLEs. Different configurations of form and content variables such as those associated with active (self-driven, interactive activities) versus didactic (reading or lecture) learning may, however, influence how presence operates and on what content it operates. We compared the influence of presence between two types of immersive VLEs (i.e., active versus didactic techniques) on comprehension and engagement-related outcomes. The findings revealed that the active VLE promoted greater presence. Although we found no relationship between presence and learning comprehension outcomes for either virtual environment, presence was related to information engagement variables in the didactic immersive VLE but not the active environment. Results demonstrate that presence is not uniformly elicited or effective across immersive VLEs. Educational delivery mode and environment complexity may influence the impact of presence on engagement.

Comparison of environmental forcings affecting suspended sediments variability in two macrotidal, highly-turbid estuaries

NASA Astrophysics Data System (ADS)

Jalón-Rojas, Isabel; Schmidt, Sabine; Sottolichio, Aldo

2017-11-01

The relative contribution of environmental forcing frequencies on turbidity variability is, for the first time, quantified at seasonal and multiannual time scales in tidal estuarine systems. With a decade of high-frequency, multi-site turbidity monitoring, the two nearby, macrotidal and highly-turbid Gironde and Loire estuaries (west France) are excellent natural laboratories for this purpose. Singular Spectrum Analyses, combined with Lomb-Scargle periodograms and Wavelet Transforms, were applied to the continuous multiannual turbidity time series. Frequencies of the main environmental factors affecting turbidity were identified: hydrological regime (high versus low river discharges), river flow variability, tidal range, tidal cycles, and turbulence. Their relative influences show similar patterns in both estuaries and depend on the estuarine region (lower or upper estuary) and the time scale (multiannual or seasonal). On the multiannual time scale, the relative contribution of tidal frequencies (tidal cycles and range) to turbidity variability decreases up-estuary from 68% to 47%, while the influence of river flow frequencies increases from 3% to 42%. On the seasonal time scale, the relative influence of forcings frequencies remains almost constant in the lower estuary, dominated by tidal frequencies (60% and 30% for tidal cycles and tidal range, respectively); in the upper reaches, it is variable depending on hydrological regime, even if tidal frequencies are responsible for up 50% of turbidity variance. These quantifications show the potential of combined spectral analyses to compare the behavior of suspended sediment in tidal estuaries throughout the world and to evaluate long-term changes in environmental forcings, especially in a context of global change. The relevance of this approach to compare nearby and overseas systems and to support management strategies is discussed (e.g., selection of effective operation frequencies/regions, prediction of the most affected regions by the implementation of operational management plans).

Evolution of Wholesale Electricity Market Design with Increasing Levels of Renewable Generation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ela, E.; Milligan, M.; Bloom, A.

2014-09-01

Variable generation such as wind and photovoltaic solar power has increased substantially in recent years. Variable generation has unique characteristics compared to the traditional technologies that supply energy in the wholesale electricity markets. These characteristics create unique challenges in planning and operating the power system, and they can also influence the performance and outcomes from electricity markets. This report focuses on two particular issues related to market design: revenue sufficiency for long-term reliability and incentivizing flexibility in short-term operations. The report provides an overview of current design and some designs that have been proposed by industry or researchers.

Smooth time-dependent receiver operating characteristic curve estimators.

PubMed

Martínez-Camblor, Pablo; Pardo-Fernández, Juan Carlos

2018-03-01

The receiver operating characteristic curve is a popular graphical method often used to study the diagnostic capacity of continuous (bio)markers. When the considered outcome is a time-dependent variable, two main extensions have been proposed: the cumulative/dynamic receiver operating characteristic curve and the incident/dynamic receiver operating characteristic curve. In both cases, the main problem for developing appropriate estimators is the estimation of the joint distribution of the variables time-to-event and marker. As usual, different approximations lead to different estimators. In this article, the authors explore the use of a bivariate kernel density estimator which accounts for censored observations in the sample and produces smooth estimators of the time-dependent receiver operating characteristic curves. The performance of the resulting cumulative/dynamic and incident/dynamic receiver operating characteristic curves is studied by means of Monte Carlo simulations. Additionally, the influence of the choice of the required smoothing parameters is explored. Finally, two real-applications are considered. An R package is also provided as a complement to this article.

The roles of constraint-based and dedication-based influences on user's continued online shopping behavior.

PubMed

Chang, Su-Chao; Chou, Chi-Min

2012-11-01

The objective of this study was to determine empirically the role of constraint-based and dedication-based influences as drivers of the intention to continue using online shopping websites. Constraint-based influences consist of two variables: trust and perceived switching costs. Dedication-based influences consist of three variables: satisfaction, perceived usefulness, and trust. The current results indicate that both constraint-based and dedication-based influences are important drivers of the intention to continue using online shopping websites. The data also shows that trust has the strongest total effect on online shoppers' intention to continue using online shopping websites. In addition, the results indicate that the antecedents of constraint-based influences, technical bonds (e.g., perceived operational competence and perceived website interactivity) and social bonds (e.g., perceived relationship investment, community building, and intimacy) have indirect positive effects on the intention to continue using online shopping websites. Based on these findings, this research suggests that online shopping websites should build constraint-based and dedication-based influences to enhance user's continued online shopping behaviors simultaneously.

Comparison of Wind Power and Load Forecasting Error Distributions: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hodge, B. M.; Florita, A.; Orwig, K.

2012-07-01

The introduction of large amounts of variable and uncertain power sources, such as wind power, into the electricity grid presents a number of challenges for system operations. One issue involves the uncertainty associated with scheduling power that wind will supply in future timeframes. However, this is not an entirely new challenge; load is also variable and uncertain, and is strongly influenced by weather patterns. In this work we make a comparison between the day-ahead forecasting errors encountered in wind power forecasting and load forecasting. The study examines the distribution of errors from operational forecasting systems in two different Independent Systemmore » Operator (ISO) regions for both wind power and load forecasts at the day-ahead timeframe. The day-ahead timescale is critical in power system operations because it serves the unit commitment function for slow-starting conventional generators.« less

Societal costs in displaced transverse olecranon fractures: using decision analysis tools to find the most cost-effective strategy between tension band wiring and locked plating.

PubMed

Francis, Tittu; Washington, Travis; Srivastava, Karan; Moutzouros, Vasilios; Makhni, Eric C; Hakeos, William

2017-11-01

Tension band wiring (TBW) and locked plating are common treatment options for Mayo IIA olecranon fractures. Clinical trials have shown excellent functional outcomes with both techniques. Although TBW implants are significantly less expensive than a locked olecranon plate, TBW often requires an additional operation for implant removal. To choose the most cost-effective treatment strategy, surgeons must understand how implant costs and return to the operating room influence the most cost-effective strategy. This cost-effective analysis study explored the optimal treatment strategies by using decision analysis tools. An expected-value decision tree was constructed to estimate costs based on the 2 implant choices. Values for critical variables, such as implant removal rate, were obtained from the literature. A Monte Carlo simulation consisting of 100,000 trials was used to incorporate variability in medical costs and implant removal rates. Sensitivity analysis and strategy tables were used to show how different variables influence the most cost-effective strategy. TBW was the most cost-effective strategy, with a cost savings of approximately $1300. TBW was also the dominant strategy by being the most cost-effective solution in 63% of the Monte Carlo trials. Sensitivity analysis identified implant costs for plate fixation and surgical costs for implant removal as the most sensitive parameters influencing the cost-effective strategy. Strategy tables showed the most cost-effective solution as 2 parameters vary simultaneously. TBW is the most cost-effective strategy in treating Mayo IIA olecranon fractures despite a higher rate of return to the operating room. Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Probabilistic Physics-Based Risk Tools Used to Analyze the International Space Station Electrical Power System Output

NASA Technical Reports Server (NTRS)

Patel, Bhogila M.; Hoge, Peter A.; Nagpal, Vinod K.; Hojnicki, Jeffrey S.; Rusick, Jeffrey J.

2004-01-01

This paper describes the methods employed to apply probabilistic modeling techniques to the International Space Station (ISS) power system. These techniques were used to quantify the probabilistic variation in the power output, also called the response variable, due to variations (uncertainties) associated with knowledge of the influencing factors called the random variables. These uncertainties can be due to unknown environmental conditions, variation in the performance of electrical power system components or sensor tolerances. Uncertainties in these variables, cause corresponding variations in the power output, but the magnitude of that effect varies with the ISS operating conditions, e.g. whether or not the solar panels are actively tracking the sun. Therefore, it is important to quantify the influence of these uncertainties on the power output for optimizing the power available for experiments.

Cardiac surgery productivity and throughput improvements.

PubMed

Lehtonen, Juha-Matti; Kujala, Jaakko; Kouri, Juhani; Hippeläinen, Mikko

2007-01-01

The high variability in cardiac surgery length--is one of the main challenges for staff managing productivity. This study aims to evaluate the impact of six interventions on open-heart surgery operating theatre productivity. A discrete operating theatre event simulation model with empirical operation time input data from 2603 patients is used to evaluate the effect that these process interventions have on the surgery output and overtime work. A linear regression model was used to get operation time forecasts for surgery scheduling while it also could be used to explain operation time. A forecasting model based on the linear regression of variables available before the surgery explains 46 per cent operating time variance. The main factors influencing operation length were type of operation, redoing the operation and the head surgeon. Reduction of changeover time between surgeries by inducing anaesthesia outside an operating theatre and by reducing slack time at the end of day after a second surgery have the strongest effects on surgery output and productivity. A more accurate operation time forecast did not have any effect on output, although improved operation time forecast did decrease overtime work. A reduction in the operation time itself is not studied in this article. However, the forecasting model can also be applied to discover which factors are most significant in explaining variation in the length of open-heart surgery. The challenge in scheduling two open-heart surgeries in one day can be partly resolved by increasing the length of the day, decreasing the time between two surgeries or by improving patient scheduling procedures so that two short surgeries can be paired. A linear regression model is created in the paper to increase the accuracy of operation time forecasting and to identify factors that have the most influence on operation time. A simulation model is used to analyse the impact of improved surgical length forecasting and five selected process interventions on productivity in cardiac surgery.

Factors influencing the drain and rinse operation of Banana screens

DOE Office of Scientific and Technical Information (OSTI.GOV)

O'Brien, M.; Firth, B.

An Australian Coal Association Research Project (ACARP) study to identify the variables and effects on Banana screens is described in this article. The impacts of the following system variables were investigated: panel angle, volumetric feed flow rate, solids content of feed screen motion, vibration frequency, magnetite content and impact of screen aperture. The article was adapted from a presentation at Coal Prep 2005, Lexington, KY, USA in May 2005. 4 refs., 8 figs., 1 tab.

Comparing Effects of Lake- and Watershed-Scale Influences on Communities of Aquatic Invertebrates in Shallow Lakes

PubMed Central

Hanson, Mark A.; Herwig, Brian R.; Zimmer, Kyle D.; Fieberg, John; Vaughn, Sean R.; Wright, Robert G.; Younk, Jerry A.

2012-01-01

Constraints on lake communities are complex and are usually studied by using limited combinations of variables derived from measurements within or adjacent to study waters. While informative, results often provide limited insight about magnitude of simultaneous influences operating at multiple scales, such as lake- vs. watershed-scale. To formulate comparisons of such contrasting influences, we explored factors controlling the abundance of predominant aquatic invertebrates in 75 shallow lakes in western Minnesota, USA. Using robust regression techniques, we modeled relative abundance of Amphipoda, small and large cladocera, Corixidae, aquatic Diptera, and an aggregate taxon that combined Ephemeroptera-Trichoptera-Odonata (ETO) in response to lake- and watershed-scale characteristics. Predictor variables included fish and submerged plant abundance, linear distance to the nearest wetland or lake, watershed size, and proportion of the watershed in agricultural production. Among-lake variability in invertebrate abundance was more often explained by lake-scale predictors than by variables based on watershed characteristics. For example, we identified significant associations between fish presence and community type and abundance of small and large cladocera, Amphipoda, Diptera, and ETO. Abundance of Amphipoda, Diptera, and Corixidae were also positively correlated with submerged plant abundance. We observed no associations between lake-watershed variables and abundance of our invertebrate taxa. Broadly, our results seem to indicate preeminence of lake-level influences on aquatic invertebrates in shallow lakes, but historical land-use legacies may mask important relationships. PMID:22970275

Minimizing variability of cascade impaction measurements in inhalers and nebulizers.

PubMed

Bonam, Matthew; Christopher, David; Cipolla, David; Donovan, Brent; Goodwin, David; Holmes, Susan; Lyapustina, Svetlana; Mitchell, Jolyon; Nichols, Steve; Pettersson, Gunilla; Quale, Chris; Rao, Nagaraja; Singh, Dilraj; Tougas, Terrence; Van Oort, Mike; Walther, Bernd; Wyka, Bruce

2008-01-01

The purpose of this article is to catalogue in a systematic way the available information about factors that may influence the outcome and variability of cascade impactor (CI) measurements of pharmaceutical aerosols for inhalation, such as those obtained from metered dose inhalers (MDIs), dry powder inhalers (DPIs) or products for nebulization; and to suggest ways to minimize the influence of such factors. To accomplish this task, the authors constructed a cause-and-effect Ishikawa diagram for a CI measurement and considered the influence of each root cause based on industry experience and thorough literature review. The results illustrate the intricate network of underlying causes of CI variability, with the potential for several multi-way statistical interactions. It was also found that significantly more quantitative information exists about impactor-related causes than about operator-derived influences, the contribution of drug assay methodology and product-related causes, suggesting a need for further research in those areas. The understanding and awareness of all these factors should aid in the development of optimized CI methods and appropriate quality control measures for aerodynamic particle size distribution (APSD) of pharmaceutical aerosols, in line with the current regulatory initiatives involving quality-by-design (QbD).

Angiographic assessment of initial balloon angioplasty results.

PubMed

Gardiner, Geoffrey A; Sullivan, Kevin L; Halpern, Ethan J; Parker, Laurence; Beck, Margaret; Bonn, Joseph; Levin, David C

2004-10-01

To determine the influence of three factors involved in the angiographic assessment of balloon angioplasty-interobserver variability, operator bias, and the definition used to determine success-on the primary (technical) results of angioplasty in the peripheral arteries. Percent stenosis in 107 lesions in lower-extremity arteries was graded by three independent, experienced vascular radiologists ("observers") before and after balloon angioplasty and their estimates were compared with the initial interpretations reported by the physician performing the procedure ("operator") and an automated quantitative computer analysis. Observer variability was measured with use of intraclass correlation coefficients and SD. Differences among the operator, observers, and the computer were analyzed with use of the Wilcoxon signed-rank test and analysis of variance. For each evaluator, the results in this series of lesions were interpreted with three different definitions of success. Estimation of residual stenosis varied by an average range of 22.76% with an average SD of 8.99. The intraclass correlation coefficients averaged 0.59 for residual stenosis after angioplasty for the three observers but decreased to 0.36 when the operator was included as the fourth evaluator. There was good to very good agreement among the three independent observers and the computer, but poor correlation with the operator (P

Analytic Thermoelectric Couple Modeling: Variable Material Properties and Transient Operation

NASA Technical Reports Server (NTRS)

Mackey, Jonathan A.; Sehirlioglu, Alp; Dynys, Fred

2015-01-01

To gain a deeper understanding of the operation of a thermoelectric couple a set of analytic solutions have been derived for a variable material property couple and a transient couple. Using an analytic approach, as opposed to commonly used numerical techniques, results in a set of useful design guidelines. These guidelines can serve as useful starting conditions for further numerical studies, or can serve as design rules for lab built couples. The analytic modeling considers two cases and accounts for 1) material properties which vary with temperature and 2) transient operation of a couple. The variable material property case was handled by means of an asymptotic expansion, which allows for insight into the influence of temperature dependence on different material properties. The variable property work demonstrated the important fact that materials with identical average Figure of Merits can lead to different conversion efficiencies due to temperature dependence of the properties. The transient couple was investigated through a Greens function approach; several transient boundary conditions were investigated. The transient work introduces several new design considerations which are not captured by the classic steady state analysis. The work helps to assist in designing couples for optimal performance, and also helps assist in material selection.

Influence of operator experience on canal preparation time when using the rotary Ni-Ti ProFile system in simulated curved canals.

PubMed

Mesgouez, C; Rilliard, F; Matossian, L; Nassiri, K; Mandel, E

2003-03-01

The aim of this study was to determine the influence of operator experience on the time needed for canal preparation when using a rotary nickel-titanium (Ni-Ti) system. A total of 100 simulated curved canals in resin blocks were used. Four operators prepared a total of 25 canals each. The operators included practitioners with prior experience of the preparation technique, and practitioners with no experience. The working length for each instrument was precisely predetermined. All canals were instrumented with rotary Ni-Ti ProFile Variable Taper Series 29 engine-driven instruments using a high-torque handpiece (Maillefer, Ballaigues, Switzerland). The time taken to prepare each canal was recorded. Significant differences between the operators were analysed using the Student's t-test and the Kruskall-Wallis and Dunn nonparametric tests. Comparison of canal preparation times demonstrated a statistically significant difference between the four operators (P < 0.001). In the inexperienced group, a significant linear regression between canal number and preparation time occurred. Time required for canal preparation was inversely related to operator experience.

Dokan Hydropower Reservoir Operation under Stochastic Conditions as Regards the Inflows and the Energy Demands

NASA Astrophysics Data System (ADS)

Izat Rashed, Ghamgeen

2018-03-01

This paper presented a way of obtaining certain operating rules on time steps for the management of a large reservoir operation with a peak hydropower plant associated to it. The rules were allowed to have the form of non-linear regression equations which link a decision variable (here the water volume in the reservoir at the end of the time step) by several parameters influencing it. This paper considered the Dokan hydroelectric development KR-Iraq, which operation data are available for. It was showing that both the monthly average inflows and the monthly power demands are random variables. A model of deterministic dynamic programming intending the minimization of the total amount of the squares differences between the demanded energy and the generated energy is run with a multitude of annual scenarios of inflows and monthly required energies. The operating rules achieved allow the efficient and safe management of the operation and it is quietly and accurately known the forecast of the inflow and of the energy demand on the next time step.

Operation of Dokan Reservoir under Stochastic Conditions as Regards the Inflows and the Energy Demands

NASA Astrophysics Data System (ADS)

Rashed, G. I.

2018-02-01

This paper presented a way of obtaining certain operating rules on time steps for the management of a large reservoir operation with a peak hydropower plant associated to it. The rules were allowed to have the form of non-linear regression equations which link a decision variable (here the water volume in the reservoir at the end of the time step) by several parameters influencing it. This paper considered the Dokan hydroelectric development KR-Iraq, which operation data are available for. It was showing that both the monthly average inflows and the monthly power demands are random variables. A model of deterministic dynamic programming intending the minimization of the total amount of the squares differences between the demanded energy and the generated energy is run with a multitude of annual scenarios of inflows and monthly required energies. The operating rules achieved allow the efficient and safe management of the operation and it is quietly and accurately known the forecast of the inflow and of the energy demand on the next time step.

Influence of median surgeon operative duration on adverse outcomes in bariatric surgery.

PubMed

Reames, Bradley N; Bacal, Daniel; Krell, Robert W; Birkmeyer, John D; Birkmeyer, Nancy J O; Finks, Jonathan F

2015-01-01

Evidence suggests that prolonged operative time adversely affects surgical outcomes. However, whether faster surgeons have better outcomes is unclear, as a surgeon׳s speed could reflect skill and efficiency, but may alternatively reflect haste. This study evaluates whether median surgeon operative time is associated with adverse surgical outcomes after laparoscopic Roux-en-Y gastric bypass. We performed a retrospective cohort study using statewide clinical registry data from the years 2006 to 2012. Surgeons were ranked by their median operative time and grouped into terciles. Multivariable logistic regression with robust standard errors was used to evaluate the influence of median surgeon operative time on 30-day surgical outcomes, adjusting for patient and surgeon characteristics, trainee involvement, concurrent procedures, and the complex interaction between these variables. A total of 16,344 patients underwent surgery during the study period. Compared to surgeons in the fastest tercile, slow surgeons required 53 additional minutes to complete a gastric bypass procedure (median [interquartile range] 139 [133-150] versus 86 [69-91], P<.001). After adjustment for patient characteristic only, slow surgeons had significantly higher adjusted rates of any complication, prolonged length of stay, emergency department visits or readmissions, and venous thromboembolism (VTE). After further adjustment for surgeon characteristics, resident involvement, and the interaction between these variables, slow surgeons had higher rates of any complication (10.5% versus 7.1%, P=.039), prolonged length of stay (14.0% versus 4.4%, P=.002), and VTE (0.39% versus .22%, P<.001). Median surgeon operative duration is independently associated with adjusted rates of certain adverse outcomes after laparoscopic Roux-en-Y gastric bypass. Improving surgeon efficiency while operating may reduce operative time and improve the safety of bariatric surgery. Copyright © 2015 American Society for Bariatric Surgery. Published by Elsevier Inc. All rights reserved.

Variability in perceived satisfaction of reservoir management objectives

USGS Publications Warehouse

Owen, W.J.; Gates, T.K.; Flug, M.

1997-01-01

Fuzzy set theory provides a useful model to address imprecision in interpreting linguistically described objectives for reservoir management. Fuzzy membership functions can be used to represent degrees of objective satisfaction for different values of management variables. However, lack of background information, differing experiences and qualifications, and complex interactions of influencing factors can contribute to significant variability among membership functions derived from surveys of multiple experts. In the present study, probabilistic membership functions are used to model variability in experts' perceptions of satisfaction of objectives for hydropower generation, fish habitat, kayaking, rafting, and scenery preservation on the Green River through operations of Flaming Gorge Dam. Degree of variability in experts' perceptions differed among objectives but resulted in substantial uncertainty in estimation of optimal reservoir releases.

Variability of particle number emissions from diesel and hybrid diesel-electric buses in real driving conditions.

PubMed

Sonntag, Darrell B; Gao, H Oliver; Holmén, Britt A

2008-08-01

A linear mixed model was developed to quantify the variability of particle number emissions from transit buses tested in real-world driving conditions. Two conventional diesel buses and two hybrid diesel-electric buses were tested throughout 2004 under different aftertreatments, fuels, drivers, and bus routes. The mixed model controlled the confounding influence of factors inherent to on-board testing. Statistical tests showed that particle number emissions varied significantly according to the after treatment, bus route, driver, bus type, and daily temperature, with only minor variability attributable to differences between fuel types. The daily setup and operation of the sampling equipment (electrical low pressure impactor) and mini-dilution system contributed to 30-84% of the total random variability of particle measurements among tests with diesel oxidation catalysts. By controlling for the sampling day variability, the model better defined the differences in particle emissions among bus routes. In contrast, the low particle number emissions measured with diesel particle filters (decreased by over 99%) did not vary according to operating conditions or bus type but did vary substantially with ambient temperature.

Overtone Mobility Spectrometry (Part 2): Theoretical Considerations of Resolving Power

PubMed Central

Valentine, Stephen J.; Stokes, Sarah T.; Kurulugama, Ruwan T.; Nachtigall, Fabiane M.; Clemmer, David E.

2009-01-01

The transport of ions through multiple drift regions is modeled in order to develop an equation that is useful for an understanding of the resolving power of an overtone mobility spectrometry (OMS) technique. It is found that resolving power is influenced by a number of experimental variables, including those that define ion mobility spectrometry (IMS) resolving power: drift field (E), drift region length (L), and buffer gas temperature (T). However, unlike IMS, the resolving power of OMS is also influenced by the number of drift regions (n), harmonic frequency value (m), and the phase number (ϕ) of the applied drift field. The OMS resolving power dependence upon the new OMS variables (n, m, and ϕ) scales differently than the square root dependence of the E, L, and T variables in IMS. The results provide insight about optimal instrumental design and operation. PMID:19230705

Hot-salt stress-corrosion of titanium alloys as related to turbine operation

NASA Technical Reports Server (NTRS)

Gray, H. R.

1972-01-01

In an effort to simulate typical compressor operating conditions of current turbine engines, special test facilities were designed. Air velocity, air pressure, air dewpoint, salt deposition temperature, salt concentration, and specimen surface condition were systematically controlled and their influence on hot-salt stress-corrosion evaluated. The influence of both continuous and cyclic stress-temperature exposures was determined. The relative susceptibility of a variety of titanium alloys in commonly used heat-treated conditions was determined. The effects of both environmental and material variables were used to interpret the behavior of titanium alloys under hot-salt stress-corrosion conditions found in jet engines and to appraise their future potential under such conditions.

Laboratory evaluation of influence of operational tolerance (acceptance criterion) on performance of hot-mix asphalt concrete.

DOT National Transportation Integrated Search

2010-06-01

The performance of flexible pavements relies heavily on the final quality of the hot-mix asphalt concrete (HMAC) as it : is produced and placed in the field. To account for production and construction variability while ensuring the quality of the : H...

Influence of Body Mass Index and Albumin on Perioperative Morbidity and Clinical Outcomes in Resected Pancreatic Adenocarcinoma

PubMed Central

Hendifar, Andrew; Osipov, Arsen; Khanuja, Jasleen; Nissen, Nicholas; Naziri, Jason; Yang, Wensha; Li, Quanlin; Tuli, Richard

2016-01-01

Obesity is a known risk factor for PDA and recent reports suggest obesity has a negative impact on clinical outcomes in patients with PDA. Pretreatment body mass index (BMI) and serum albumin (SA) have been shown to be associated with worse overall survival in patients with advanced and metastatic PDA. However, minimal data exists on the impact of BMI and SA on perioperative and long-term clinical outcomes in patients with early-stage resected PDA. Herein, we report on the impact of these variables on perioperative clinical outcomes, overall survival (OS) and disease free survival (DFS) in patients with resected PDA. With IRB approval, we evaluated 1,545 patients with PDA treated at a single institution from 2007–2013 and identified 106 patients who underwent upfront resection with curative intent. BMI and SA were calculated preoperatively and at the time of last clinical evaluation. Influence of preoperative BMI, SA, change in either variable, and influence of other clinical and pathologic variables on perioperative morbidity and mortality was assessed. The impact of these variables on DFS and OS was assessed with cox regression modeling and ANOVA. Actuarial estimates for DFS and OS were calculated using Kaplan-Meier methods. Median follow up time was 16 months (3–89). Mean age was 68 years. Median survival was 14 months (3–65) and median time to recurrence was 11 months (1–79). Length of hospital stay was associated with BMI (p = .023), change in BMI (p = .003) and SA (p = .004). Post-operative transfusion rate was associated with SA (p = .021). There was a strong correlation between BMI change and positive margin (p = .04) and lymph node status (p = .01). On multivariate analysis, change in SA (p = .03) and node positivity (p = .008) were associated with decreased DFS. Additionally, preoperative SA (p = .023), node positivity (p = .026) and poor differentiation (p = .045) were associated with worse OS on multivariate analysis. Low preoperative SA was associated with worse DFS and OS in patients with resected PDA. Lower BMI and SA were associated with longer post-operative hospital stay. Our study is one of the first to describe how pre-operative BMI and SA and post-operative changes in these variables impact clinical and perioperative outcomes. This data supports nutritional status and weight loss as predictors of outcome in resected pancreatic cancer patients and warrants further prospective investigation. PMID:27015568

Influence of Body Mass Index and Albumin on Perioperative Morbidity and Clinical Outcomes in Resected Pancreatic Adenocarcinoma.

PubMed

Hendifar, Andrew; Osipov, Arsen; Khanuja, Jasleen; Nissen, Nicholas; Naziri, Jason; Yang, Wensha; Li, Quanlin; Tuli, Richard

2016-01-01

Obesity is a known risk factor for PDA and recent reports suggest obesity has a negative impact on clinical outcomes in patients with PDA. Pretreatment body mass index (BMI) and serum albumin (SA) have been shown to be associated with worse overall survival in patients with advanced and metastatic PDA. However, minimal data exists on the impact of BMI and SA on perioperative and long-term clinical outcomes in patients with early-stage resected PDA. Herein, we report on the impact of these variables on perioperative clinical outcomes, overall survival (OS) and disease free survival (DFS) in patients with resected PDA. With IRB approval, we evaluated 1,545 patients with PDA treated at a single institution from 2007-2013 and identified 106 patients who underwent upfront resection with curative intent. BMI and SA were calculated preoperatively and at the time of last clinical evaluation. Influence of preoperative BMI, SA, change in either variable, and influence of other clinical and pathologic variables on perioperative morbidity and mortality was assessed. The impact of these variables on DFS and OS was assessed with cox regression modeling and ANOVA. Actuarial estimates for DFS and OS were calculated using Kaplan-Meier methods. Median follow up time was 16 months (3-89). Mean age was 68 years. Median survival was 14 months (3-65) and median time to recurrence was 11 months (1-79). Length of hospital stay was associated with BMI (p = .023), change in BMI (p = .003) and SA (p = .004). Post-operative transfusion rate was associated with SA (p = .021). There was a strong correlation between BMI change and positive margin (p = .04) and lymph node status (p = .01). On multivariate analysis, change in SA (p = .03) and node positivity (p = .008) were associated with decreased DFS. Additionally, preoperative SA (p = .023), node positivity (p = .026) and poor differentiation (p = .045) were associated with worse OS on multivariate analysis. Low preoperative SA was associated with worse DFS and OS in patients with resected PDA. Lower BMI and SA were associated with longer post-operative hospital stay. Our study is one of the first to describe how pre-operative BMI and SA and post-operative changes in these variables impact clinical and perioperative outcomes. This data supports nutritional status and weight loss as predictors of outcome in resected pancreatic cancer patients and warrants further prospective investigation.

Comparison of the basin-scale effect of dredging operations and natural estuarine processes on suspended sediment concentration

USGS Publications Warehouse

Schoellhamer, D.H.

2002-01-01

Suspended sediment concentration (SSC) data from San Pablo Bay, California, were analyzed to compare the basin-scale effect of dredging and disposal of dredged material (dredging operations) and natural estuarine processes. The analysis used twelve 3-wk to 5-wk periods of mid-depth and near-bottom SSC data collected at Point San Pablo every 15 min from 1993-1998. Point San Pablo is within a tidal excursion of a dredged-material disposal site. The SSC data were compared to dredging volume, Julian day, and hydrodynamic and meteorological variables that could affect SSC. Kendall's ??, Spearman's ??, and weighted (by the fraction of valid data in each period) Spearman's ??w correlation coefficients of the variables indicated which variables were significantly correlated with SSC. Wind-wave resuspension had the greatest effect on SSC. Median water-surface elevation was the primary factor affecting mid-depth SSC. Greater depths inhibit wind-wave resuspension of bottom sediment and indicate greater influence of less turbid water from down estuary. Seasonal variability in the supply of erodible sediment is the primary factor affecting near-bottom SSC. Natural physical processes in San Pablo Bay are more areally extensive, of equal or longer duration, and as frequent as dredging operations (when occurring), and they affect SSC at the tidal time scale. Natural processes control SSC at Point San Pablo even when dredging operations are occurring.

Variability in hand-arm vibration during grinding operations.

PubMed

Liljelind, Ingrid; Wahlström, Jens; Nilsson, Leif; Toomingas, Allan; Burström, Lage

2011-04-01

Measurements of exposure to vibrations from hand-held tools are often conducted on a single occasion. However, repeated measurements may be crucial for estimating the actual dose with good precision. In addition, knowledge of determinants of exposure could be used to improve working conditions. The aim of this study was to assess hand-arm vibration (HAV) exposure during different grinding operations, in order to obtain estimates of the variance components and to evaluate the effect of work postures. Ten experienced operators used two compressed air-driven angle grinders of the same make in a simulated work task at a workplace. One part of the study consisted of using a grinder while assuming two different working postures: at a standard work bench (low) and on a wall with arms elevated and the work area adjusted to each operator's height (high). The workers repeated the task three times. In another part of the study, investigating the wheel wear, for each grinder, the operators used two new grinding wheels and with each wheel the operator performed two consecutive 1-min grinding tasks. Both grinding tasks were conducted on weld puddles of mild steel on a piece of mild steel. Measurements were taken according to ISO-standard 5349 [the equivalent hand-arm-weighted acceleration (m s(-2)) averaged over 1 min]. Mixed- and random-effects models were used to investigate the influence of the fixed variables and to estimate variance components. The equivalent hand-arm-weighted acceleration assessed when the task was performed on the bench and at the wall was 3.2 and 3.3 m s(-2), respectively. In the mixed-effects model, work posture was not a significant variable. The variables 'operator' and 'grinder' together explained only 12% of the exposure variability and 'grinding wheel' explained 47%; the residual variability of 41% remained unexplained. When the effect of grinding wheel wear was investigated in the random-effects model, 37% of the variability was associated with the wheel while minimal variability was associated with the operator or the grinder and 37% was unexplained. The interaction effect of grinder and operator explained 18% of the variability. In the wheel wear test, the equivalent hand-arm-weighted accelerations for Grinder 1 during the first and second grinding minutes were 3.4 and 2.9 m s(-2), respectively, and for Grinder 2, they were 3.1 and 2.9 m s(-2), respectively. For Grinder 1, the equivalent hand-arm-weighted acceleration during the first grinding minute was significantly higher (P = 0.04) than during the second minute. Work posture during grinding operations does not appear to affect the level of HAV. Grinding wheels explained much of the variability in this study, but almost 40% of the variance remained unexplained. The considerable variability in the equivalent hand-arm-weighted acceleration has an impact on the risk assessment at both the group and the individual level.

Influence of UV illumination on the cold temperature operation of a LiNbO(3) Q-switched Nd:YAG laser.

PubMed

Cole, Brian; Goldberg, Lew; King, Vernon; Leach, Jeff

2010-04-26

UV illumination of a lithium niobate Q-switch was demonstrated as an effective means to eliminate a loss in hold-off and associated prelasing that occurs under cold temperature operation of Q-switched lasers. This degradation occurs due to the pyroelectric effect, where an accumulation of charge on crystal faces results in a reduction in the Q-switch hold-off and a spatially variable loss of the Q-switch in its high-transmission state, both resulting in lowering of the maximum Q-switched pulse energy. With UV illumination, the resulting creation of photo-generated carriers was shown to be effective in eliminating both of these effects. A Q-switched Nd:YAG laser utilizing UV-illuminated LiNbO(3) was shown to operate under cold temperatures without prelasing or spatially variable loss.

Factors that affect the fatigue strength of power transmission shafting

NASA Technical Reports Server (NTRS)

Loewenthal, S. H.

1984-01-01

A long standing objective in the design of power transmission shafting is to eliminate excess shaft material without compromising operational reliability. A shaft design method is presented which accounts for variable amplitude loading histories and their influence on limited life designs. The effects of combined bending and torsional loading are considered along with a number of application factors known to influence the fatigue strength of shafting materials. Among the factors examined are surface condition, size, stress concentration, residual stress and corrosion fatigue.

Online Lexical Competition during Spoken Word Recognition and Word Learning in Children and Adults

ERIC Educational Resources Information Center

Henderson, Lisa; Weighall, Anna; Brown, Helen; Gaskell, Gareth

2013-01-01

Lexical competition that occurs as speech unfolds is a hallmark of adult oral language comprehension crucial to rapid incremental speech processing. This study used pause detection to examine whether lexical competition operates similarly at 7-8 years and tested variables that influence "online" lexical activity in adults. Children…

Genetic and Environmental Influences on Inattention, Hyperactivity-Impulsivity, and Reading: Kindergarten to Grade 2

ERIC Educational Resources Information Center

Ebejer, Jane L.; Coventry, William L.; Byrne, Brian; Willcutt, Erik G.; Olson, Richard K.; Corley, Robin; Samuelsson, Stefan

2010-01-01

Twin children from Australia, Scandinavia, and the United States were assessed for inattention, hyperactivity-impulsivity, and reading across the first 3 school years. Univariate behavior-genetic analyses indicated substantial heritability for all three variables in all years. Longitudinal analyses showed one genetic source operating across the…

Understanding the Interdependencies Between Composition, Microstructure, and Continuum Variables and Their Influence on the Fracture Toughness of α/β-Processed Ti-6Al-4V

NASA Astrophysics Data System (ADS)

Collins, P. C.; Koduri, S.; Dixit, V.; Fraser, H. L.

2018-03-01

The fracture toughness of a material depends upon the material's composition and microstructure, as well as other material properties operating at the continuum level. The interrelationships between these variables are complex, and thus difficult to interpret, especially in multi-component, multi-phase ductile engineering alloys such as α/β-processed Ti-6Al-4V (nominal composition, wt pct). Neural networks have been used to elucidate how variables such as composition and microstructure influence the fracture toughness directly ( i.e., via a crack initiation or propagation mechanism)—and independent of the influence of the same variables influence on the yield strength and plasticity of the material. The variables included in the models and analysis include (i) alloy composition, specifically, Al, V, O, and Fe; (ii) materials microstructure, including phase fractions and average sizes of key microstructural features; (iii) the yield strength and reduction in area obtained from uniaxial tensile tests; and (iv) an assessment of the degree to which plane strain conditions were satisfied by including a factor related to the plane strain thickness. Once trained, virtual experiments have been conducted which permit the determination of each variable's functional dependency on the resulting fracture toughness. Given that the database includes both K 1 C and K Q values, as well as the in-plane component of the stress state of the crack tip, it is possible to quantitatively assess the effect of sample thickness on K Q and the degree to which the K Q and K 1 C values may vary. These interpretations drawn by comparing multiple neural networks have a significant impact on the general understanding of how the microstructure influences the fracture toughness in ductile materials, as well as an ability to predict the fracture toughness of α/β-processed Ti-6Al-4V.

Simulation of long-term influence from technical systems on permafrost with various short-scale and hourly operation modes in Arctic region

NASA Astrophysics Data System (ADS)

Vaganova, N. A.

2017-12-01

Technogenic and climatic influences have a significant impact on the degradation of permafrost. Long-term forecasts of such changes during long-time periods have to be taken into account in the oil and gas and construction industries in view to development the Arctic and Subarctic regions. There are considered constantly operating technical systems (for example, oil and gas wells) that affect changes in permafrost, as well as the technical systems that have a short-term impact on permafrost (for example, flare systems for emergency flaring of associated gas). The second type of technical systems is rather complex for simulation, since it is required to reserve both short and long-scales in computations with variable time steps describing the complex technological processes. The main attention is paid to the simulation of long-term influence on the permafrost from the second type of the technical systems.

Nursing home cost and ownership type: evidence of interaction effects.

PubMed

Arling, G; Nordquist, R H; Capitman, J A

1987-06-01

Due to steadily increasing public expenditures for nursing home care, much research has focused on factors that influence nursing home costs, especially for Medicaid patients. Nursing home cost function studies have typically used a number of predictor variables in a multiple regression analysis to determine the effect of these variables on operating cost. Although several authors have suggested that nursing home ownership types have different goal orientations, not necessarily based on economic factors, little attention has been paid to this issue in empirical research. In this study, data from 150 Virginia nursing homes were used in multiple regression analysis to examine factors accounting for nursing home operating costs. The context of the study was the Virginia Medicaid reimbursement system, which has intermediate care and skilled nursing facility (ICF and SNF) facility-specific per diem rates, set according to facility cost histories. The analysis revealed interaction effects between ownership and other predictor variables (e.g., percentage Medicaid residents, case mix, and region), with predictor variables having different effects on cost depending on ownership type. Conclusions are drawn about the goal orientations and behavior of chain-operated, individual for-profit, and public and nonprofit facilities. The implications of these findings for long-term care reimbursement policies are discussed.

Nursing home cost and ownership type: evidence of interaction effects.

PubMed Central

Arling, G; Nordquist, R H; Capitman, J A

1987-01-01

Due to steadily increasing public expenditures for nursing home care, much research has focused on factors that influence nursing home costs, especially for Medicaid patients. Nursing home cost function studies have typically used a number of predictor variables in a multiple regression analysis to determine the effect of these variables on operating cost. Although several authors have suggested that nursing home ownership types have different goal orientations, not necessarily based on economic factors, little attention has been paid to this issue in empirical research. In this study, data from 150 Virginia nursing homes were used in multiple regression analysis to examine factors accounting for nursing home operating costs. The context of the study was the Virginia Medicaid reimbursement system, which has intermediate care and skilled nursing facility (ICF and SNF) facility-specific per diem rates, set according to facility cost histories. The analysis revealed interaction effects between ownership and other predictor variables (e.g., percentage Medicaid residents, case mix, and region), with predictor variables having different effects on cost depending on ownership type. Conclusions are drawn about the goal orientations and behavior of chain-operated, individual for-profit, and public and nonprofit facilities. The implications of these findings for long-term care reimbursement policies are discussed. PMID:3301746

Serum levels of uric acid and diabetes mellitus influence survival after surgery for primary hyperparathyroidism: a prospective cohort study.

PubMed

Bergenfelz, Anders; Bladström, Anna; Their, Mark; Nordenström, Erik; Valdemarsson, Stig; Westerdahl, Johan

2007-07-01

Primary hyperparathyroidism (pHPT) is associated with an increased mortality attributable to cardiovascular disease (CVD), suggested to be alleviated by surgery. The exact mechanism of the beneficial influence of parathyroidectomy on survival is unknown. Furthermore, studies suggest that there is no increased mortality compared to the mortality rate in the general population during recent years. This study therefore investigated relative survival (RS), as well overall mortality associated with the clinical and biochemical variables in patients undergoing operation for sporadic pHPT. Furthermore, the influence of surgery on biochemical variables associated with pHPT was analyzed. A group of 323 patients with sporadic pHPT operated between September 1989 and July 2003 were followed from surgery over a 10-year period. The median and mean follow-up time was 69 and 70 months, respectively (range: 1-120 months). Relative survival (RS) was calculated, and the impact of clinical and biochemical variables on overall death were evaluated. Postoperatively, serum levels of triglycerides and uric acid decreased. Glucose levels and glomerular filtration rate remained unchanged. A decreased RS was evident during the latter part of the 10 year follow-up period. In the multivariate Cox-analysis, diabetes mellitus (hazard ratio [HR] = 2.8, 95%; confidence interval [CI] 1.2-6.7), and the combination of an increased level of serum uric acid and cardiovascular disease (CVD) (HR = 8.6, 95%; CI 1.5-49.7) was associated with a higher mortality. The increased risk of death was evident for patients with persistently increased levels of uric acid postoperatively (HR = 4.8, 95%; CI = 1.4-16.01). Patients undergoing operation for pHPT had a decreased RS during a 10-year follow-up compared to the general population. This decrease in RS is associated with diabetes mellitus and increased levels of uric acid pre-and postoperatively.

Controlling for exogenous environmental variables when using data envelopment analysis for regional environmental assessments.

PubMed

Macpherson, Alexander J; Principe, Peter P; Shao, Yang

2013-04-15

Researchers are increasingly using data envelopment analysis (DEA) to examine the efficiency of environmental policies and resource allocations. An assumption of the basic DEA model is that decisionmakers operate within homogeneous environments. But, this assumption is not valid when environmental performance is influenced by variables beyond managerial control. Understanding the influence of these variables is important to distinguish between characterizing environmental conditions and identifying opportunities to improve environmental performance. While environmental assessments often focus on characterizing conditions, the point of using DEA is to identify opportunities to improve environmental performance and thereby prevent (or rectify) an inefficient allocation of resources. We examine the role of exogenous variables such as climate, hydrology, and topography in producing environmental impacts such as deposition, runoff, invasive species, and forest fragmentation within the United States Mid-Atlantic region. We apply a four-stage procedure to adjust environmental impacts in a DEA model that seeks to minimize environmental impacts while obtaining given levels of socioeconomic outcomes. The approach creates a performance index that bundles multiple indicators while adjusting for variables that are outside management control, offering numerous advantages for environmental assessment. Published by Elsevier Ltd.

Computational Analysis for Rocket-Based Combined-Cycle Systems During Rocket-Only Operation

NASA Technical Reports Server (NTRS)

Steffen, C. J., Jr.; Smith, T. D.; Yungster, S.; Keller, D. J.

2000-01-01

A series of Reynolds-averaged Navier-Stokes calculations were employed to study the performance of rocket-based combined-cycle systems operating in an all-rocket mode. This parametric series of calculations were executed within a statistical framework, commonly known as design of experiments. The parametric design space included four geometric and two flowfield variables set at three levels each, for a total of 729 possible combinations. A D-optimal design strategy was selected. It required that only 36 separate computational fluid dynamics (CFD) solutions be performed to develop a full response surface model, which quantified the linear, bilinear, and curvilinear effects of the six experimental variables. The axisymmetric, Reynolds-averaged Navier-Stokes simulations were executed with the NPARC v3.0 code. The response used in the statistical analysis was created from Isp efficiency data integrated from the 36 CFD simulations. The influence of turbulence modeling was analyzed by using both one- and two-equation models. Careful attention was also given to quantify the influence of mesh dependence, iterative convergence, and artificial viscosity upon the resulting statistical model. Thirteen statistically significant effects were observed to have an influence on rocket-based combined-cycle nozzle performance. It was apparent that the free-expansion process, directly downstream of the rocket nozzle, can influence the Isp efficiency. Numerical schlieren images and particle traces have been used to further understand the physical phenomena behind several of the statistically significant results.

Crosswinds Effect on the Thermal Performance of Wet Cooling Towers Under Variable Operating Conditions

NASA Astrophysics Data System (ADS)

Chen, You Liang; Shi, Yong Feng; Hao, Jian Gang; Chang, Hao; Sun, Feng Zhong

2018-01-01

In order to quantitatively analyze the influence of the variable operating parameters on the cooling performance of natural draft wet cooling towers (NDWCTs), a hot model test system was set up with adjustable ambient temperature and humidity, circulating water flowrate and temperature. In order to apply the hot model test results to the real tower, the crosswind Froude number is defined. The results show that the crosswind has a negative effect on the thermal performance of the cooling tower, and there is a critical crosswind velocity corresponding to the lowest cooling efficiency. According to the crosswind Froude number similarity, when the ambient temperature decreases, or the circulating water flowrate and temperature increase, the cooling tower draft force will increase, and the critical crosswind velocity will increase correspondingly.

The interprocess NIR sampling as an alternative approach to multivariate statistical process control for identifying sources of product-quality variability.

PubMed

Marković, Snežana; Kerč, Janez; Horvat, Matej

2017-03-01

We are presenting a new approach of identifying sources of variability within a manufacturing process by NIR measurements of samples of intermediate material after each consecutive unit operation (interprocess NIR sampling technique). In addition, we summarize the development of a multivariate statistical process control (MSPC) model for the production of enteric-coated pellet product of the proton-pump inhibitor class. By developing provisional NIR calibration models, the identification of critical process points yields comparable results to the established MSPC modeling procedure. Both approaches are shown to lead to the same conclusion, identifying parameters of extrusion/spheronization and characteristics of lactose that have the greatest influence on the end-product's enteric coating performance. The proposed approach enables quicker and easier identification of variability sources during manufacturing process, especially in cases when historical process data is not straightforwardly available. In the presented case the changes of lactose characteristics are influencing the performance of the extrusion/spheronization process step. The pellet cores produced by using one (considered as less suitable) lactose source were on average larger and more fragile, leading to consequent breakage of the cores during subsequent fluid bed operations. These results were confirmed by additional experimental analyses illuminating the underlying mechanism of fracture of oblong pellets during the pellet coating process leading to compromised film coating.

Defining process design space for a hydrophobic interaction chromatography (HIC) purification step: application of quality by design (QbD) principles.

PubMed

Jiang, Canping; Flansburg, Lisa; Ghose, Sanchayita; Jorjorian, Paul; Shukla, Abhinav A

2010-12-15

The concept of design space has been taking root under the quality by design paradigm as a foundation of in-process control strategies for biopharmaceutical manufacturing processes. This paper outlines the development of a design space for a hydrophobic interaction chromatography (HIC) process step. The design space included the impact of raw material lot-to-lot variability and variations in the feed stream from cell culture. A failure modes and effects analysis was employed as the basis for the process characterization exercise. During mapping of the process design space, the multi-dimensional combination of operational variables were studied to quantify the impact on process performance in terms of yield and product quality. Variability in resin hydrophobicity was found to have a significant influence on step yield and high-molecular weight aggregate clearance through the HIC step. A robust operating window was identified for this process step that enabled a higher step yield while ensuring acceptable product quality. © 2010 Wiley Periodicals, Inc.

Genetic influences on heart rate variability

PubMed Central

Golosheykin, Simon; Grant, Julia D.; Novak, Olga V.; Heath, Andrew C.; Anokhin, Andrey P.

2016-01-01

Heart rate variability (HRV) is the variation of cardiac inter-beat intervals over time resulting largely from the interplay between the sympathetic and parasympathetic branches of the autonomic nervous system. Individual differences in HRV are associated with emotion regulation, personality, psychopathology, cardiovascular health, and mortality. Previous studies have shown significant heritability of HRV measures. Here we extend genetic research on HRV by investigating sex differences in genetic underpinnings of HRV, the degree of genetic overlap among different measurement domains of HRV, and phenotypic and genetic relationships between HRV and the resting heart rate (HR). We performed electrocardiogram (ECG) recordings in a large population-representative sample of young adult twins (n = 1060 individuals) and computed HRV measures from three domains: time, frequency, and nonlinear dynamics. Genetic and environmental influences on HRV measures were estimated using linear structural equation modeling of twin data. The results showed that variability of HRV and HR measures can be accounted for by additive genetic and non-shared environmental influences (AE model), with no evidence for significant shared environmental effects. Heritability estimates ranged from 47 to 64%, with little difference across HRV measurement domains. Genetic influences did not differ between genders for most variables except the square root of the mean squared differences between successive R-R intervals (RMSSD, higher heritability in males) and the ratio of low to high frequency power (LF/HF, distinct genetic factors operating in males and females). The results indicate high phenotypic and especially genetic correlations between HRV measures from different domains, suggesting that >90% of genetic influences are shared across measures. Finally, about 40% of genetic variance in HRV was shared with HR. In conclusion, both HR and HRV measures are highly heritable traits in the general population of young adults, with high degree of genetic overlap across different measurement domains. PMID:27114045

Factors that affect the fatigue strength of power transmission shafting and their impact on design

NASA Technical Reports Server (NTRS)

Leowenthal, S. H.

1986-01-01

A long standing objective in the design of power transmission shafting is to eliminate excess shaft material without compromising operational reliability. A shaft design method is presented which accounts for variable amplitude loading histories and their influence on limited life designs. The effects of combined bending and torsional loading are considered along with a number of application factors known to influence the fatigue strength of shafting materials. Among the factors examined are surface condition, size, stress concentration, residual stress and corrosion fatigue.

Design and optimisation of novel configurations of stormwater constructed wetlands

NASA Astrophysics Data System (ADS)

Kiiza, Christopher

2017-04-01

Constructed wetlands (CWs) are recognised as a cost-effective technology for wastewater treatment. CWs have been deployed and could be retrofitted into existing urban drainage systems to prevent surface water pollution, attenuate floods and act as sources for reusable water. However, there exist numerous criteria for design configuration and operation of CWs. The aim of the study was to examine effects of design and operational variables on performance of CWs. To achieve this, 8 novel designs of vertical flow CWs were continuously operated and monitored (weekly) for 2years. Pollutant removal efficiency in each CW unit was evaluated from physico-chemical analyses of influent and effluent water samples. Hybrid optimised multi-layer perceptron artificial neural networks (MLP ANNs) were applied to simulate treatment efficiency in the CWs. Subsequently, predictive and analytical models were developed for each design unit. Results show models have sound generalisation abilities; with various design configurations and operational variables influencing performance of CWs. Although some design configurations attained faster and higher removal efficiencies than others; all 8 CW designs produced effluents permissible for discharge into watercourses with strict regulatory standards.

Leader--member exchange, differentiation, and psychological contract fulfillment: a multilevel examination.

PubMed

Henderson, David J; Wayne, Sandy J; Shore, Lynn M; Bommer, William H; Tetrick, Lois E

2008-11-01

Prior integrations of the leader-member exchange (LMX) and psychological contract literatures have not clarified how within-group LMX differentiation influences employees' attitudes and behaviors in the employment relationship. Therefore, using a sample of 278 members and managers of 31 intact work groups at 4 manufacturing plants, the authors examined how LMX operating at the within-group level (relative LMX, or RLMX) and the group level influenced perceptions of psychological contract fulfillment and employee-level outcomes. Controlling for individual-level perceptions of LMX quality, results indicated a positive relationship between RLMX and fulfillment, which was strengthened as group-level variability in LMX quality increased. Perceptions of fulfillment mediated the relationship between RLMX and performance and sportsmanship behaviors. The importance of conceptualizing LMX as simultaneously operating at multiple levels is highlighted.

Modeling vehicle operating speed on urban roads in Montreal: a panel mixed ordered probit fractional split model.

PubMed

Eluru, Naveen; Chakour, Vincent; Chamberlain, Morgan; Miranda-Moreno, Luis F

2013-10-01

Vehicle operating speed measured on roadways is a critical component for a host of analysis in the transportation field including transportation safety, traffic flow modeling, roadway geometric design, vehicle emissions modeling, and road user route decisions. The current research effort contributes to the literature on examining vehicle speed on urban roads methodologically and substantively. In terms of methodology, we formulate a new econometric model framework for examining speed profiles. The proposed model is an ordered response formulation of a fractional split model. The ordered nature of the speed variable allows us to propose an ordered variant of the fractional split model in the literature. The proposed formulation allows us to model the proportion of vehicles traveling in each speed interval for the entire segment of roadway. We extend the model to allow the influence of exogenous variables to vary across the population. Further, we develop a panel mixed version of the fractional split model to account for the influence of site-specific unobserved effects. The paper contributes substantively by estimating the proposed model using a unique dataset from Montreal consisting of weekly speed data (collected in hourly intervals) for about 50 local roads and 70 arterial roads. We estimate separate models for local roads and arterial roads. The model estimation exercise considers a whole host of variables including geometric design attributes, roadway attributes, traffic characteristics and environmental factors. The model results highlight the role of various street characteristics including number of lanes, presence of parking, presence of sidewalks, vertical grade, and bicycle route on vehicle speed proportions. The results also highlight the presence of site-specific unobserved effects influencing the speed distribution. The parameters from the modeling exercise are validated using a hold-out sample not considered for model estimation. The results indicate that the proposed panel mixed ordered probit fractional split model offers promise for modeling such proportional ordinal variables. Copyright © 2013 Elsevier Ltd. All rights reserved.

Trust in automation: integrating empirical evidence on factors that influence trust.

PubMed

Hoff, Kevin Anthony; Bashir, Masooda

2015-05-01

We systematically review recent empirical research on factors that influence trust in automation to present a three-layered trust model that synthesizes existing knowledge. Much of the existing research on factors that guide human-automation interaction is centered around trust, a variable that often determines the willingness of human operators to rely on automation. Studies have utilized a variety of different automated systems in diverse experimental paradigms to identify factors that impact operators' trust. We performed a systematic review of empirical research on trust in automation from January 2002 to June 2013. Papers were deemed eligible only if they reported the results of a human-subjects experiment in which humans interacted with an automated system in order to achieve a goal. Additionally, a relationship between trust (or a trust-related behavior) and another variable had to be measured. All together, 101 total papers, containing 127 eligible studies, were included in the review. Our analysis revealed three layers of variability in human-automation trust (dispositional trust, situational trust, and learned trust), which we organize into a model. We propose design recommendations for creating trustworthy automation and identify environmental conditions that can affect the strength of the relationship between trust and reliance. Future research directions are also discussed for each layer of trust. Our three-layered trust model provides a new lens for conceptualizing the variability of trust in automation. Its structure can be applied to help guide future research and develop training interventions and design procedures that encourage appropriate trust. © 2014, Human Factors and Ergonomics Society.

Seasonal Variability Study of the Tropospheric Zenithal Delay in the South America using regional Numerical Weather Prediction model

NASA Astrophysics Data System (ADS)

Sapucci, L. F.; Monico, J. G.; Machado, L. T.

2007-05-01

In 2010 a new navigation and administration system of the air traffic, denominated CNS-ATM (Communication Navigation Surveillance - Air Traffic Management) should be running operationally in South America. This new system will basically employ the positioning techniques by satellites to the management and air traffic control. However, the efficiency of this new system demands the knowledge of the behavior of the atmosphere, consequently, an appropriated Zenithal Tropospheric Delay (ZTD) modeling in a regional scale. The predictions of ZTD values from Numeric Weather Prediction (NWP), denominated here dynamic modeling, is an alternative to model the atmospheric gases effects in the radio-frequency signals in real time. Brazilian Center for Weather Forecasting and Climate Studies (CPTEC) of the National Institute for Space Research (INPE), jointly with researchers from UNESP (Sao Paulo State University), has generated operationally prediction of ZTD values to South America Continent (available in the electronic address http:satelite.cptec.inpe.br/htmldocs/ztd/zenithal.htm). The available regional version is obtained using ETA model (NWP model with horizontal resolution of 20 km and 42 levels in the vertical). The application of NWP permit assess the temporal and spatial variation of ZTD values, which is an important characteristic of this techniques. The aim of the present paper is to investigate the ZTD seasonal variability over South America continent. A variability analysis of the ZTD components [hydrostatic(ZHD) and wet(ZWD)] is also presented, as such as discussion of main factors that influence this variation in this region. The hydrostatic component variation is related with atmospheric pressure oscillation, which is influenced by relief and high pressure centers that prevail over different region of the South America continent. The wet component oscillation is due to the temperature and humidity variability, which is also influenced by relief and by synoptic events like: the penetration the cold front from Antarctic pole into the continent and occurrence of humidity convergence zones. In South America there are two main convergence zones that has strong influence in the troposphere variability, the ITCZ (Inter Tropical Convergence Zone) and the SACZ (South Atlantic Convergence Zone) zones. These convergence zones are characterized by an extensive precipitation band and high nebulosity almost stationary. The physical processes associated with these convergence zones present strong impacts in the variability of ZWD values. This work aims to contribute with ZTD modeling over South America continent using NWP to identify where and when the ZTD values present lower predictability in this region, and consequently, minimizing the error in the GNSS positioning that apply this technique.

Controlling Flexible Robot Arms Using High Speed Dynamics Process

NASA Technical Reports Server (NTRS)

Jain, Abhinandan (Inventor)

1996-01-01

A robot manipulator controller for a flexible manipulator arm having plural bodies connected at respective movable hinges and flexible in plural deformation modes corresponding to respective modal spatial influence vectors relating deformations of plural spaced nodes of respective bodies to the plural deformation modes, operates by computing articulated body quantities for each of the bodies from respective modal spatial influence vectors, obtaining specified body forces for each of the bodies, and computing modal deformation accelerations of the nodes and hinge accelerations of the hinges from the specified body forces, from the articulated body quantities and from the modal spatial influence vectors. In one embodiment of the invention, the controller further operates by comparing the accelerations thus computed to desired manipulator motion to determine a motion discrepancy, and correcting the specified body forces so as to reduce the motion discrepancy. The manipulator bodies and hinges are characterized by respective vectors of deformation and hinge configuration variables, and computing modal deformation accelerations and hinge accelerations is carried out for each one of the bodies beginning with the outermost body by computing a residual body force from a residual body force of a previous body and from the vector of deformation and hinge configuration variables, computing a resultant hinge acceleration from the body force, the residual body force and the articulated hinge inertia, and revising the residual body force modal body acceleration.

Ecological Settings and State Economies as Factor Inputs in the Provision of Outdoor Recreation

NASA Astrophysics Data System (ADS)

Siderelis, Christos; Smith, Jordan W.

2013-09-01

State parks play a substantial role in the provision of outdoor recreation opportunities within the United States. Park operators must make crucial decisions in how they allocate capital expenditures, labor, and parkland to maintain recreation opportunities. Their decisions are influenced, in part, by the ecological characteristics of their state's park system as well as the vitality of their state's economy. In this research, we incorporate the characteristics of states' ecosystems and their local economies into a formal production analysis of the states' park systems from the years 1986 to 2011. Our analysis revealed all three factors of production were positive and inelastic. Expenditures on labor had the largest effect on both park utilization and operational expenditures. Our analysis also found a large degree of variability in the effects of ecological characteristics on both utilization and operating expenditures. Parkland utilization and operational expenditures were more elastic in areas such as Oceania and Mediterranean California relative to other ecological regions. These findings lead us to conclude that state park operators will experience variable levels of difficulty in both accommodating increasing demands for recreation from state parks and maintaining the existing quality of outdoor recreation provided within their system.

Influence of hospital-level practice patterns on variation in the application of minimally invasive surgery in United States pediatric patients.

PubMed

Train, Arianne T; Harmon, Carroll M; Rothstein, David H

2017-10-01

Although disparities in access to minimally invasive surgery are thought to exist in pediatric surgical patients in the United States, hospital-level practice patterns have not been evaluated as a possible contributing factor. Retrospective cohort study using the Kids' Inpatient Database, 2012. Odds ratios of undergoing a minimally invasive compared to open operation were calculated for six typical pediatric surgical operations after adjustment for multiple patient demographic and hospital-level variables. Further adjustment to the regression model was made by incorporating hospital practice patterns, defined as operation-specific minimally invasive frequency and volume. Age was the most significant patient demographic factor affecting application of minimally invasive surgery for all procedures. For several procedures, adjusting for individual hospital practice patterns removed race- and income-based disparities seen in performance of minimally invasive operations. Disparities related to insurance status were not affected by the same adjustment. Variation in the application of minimally invasive surgery in pediatric surgical patients is primarily influenced by patient age and the type of procedure performed. Perceived disparities in access related to some socioeconomic factors are decreased but not eliminated by accounting for individual hospital practice patterns, suggesting that complex underlying factors influence application of advanced surgical techniques. II. Copyright © 2017 Elsevier Inc. All rights reserved.

Object recognition contributions to figure-ground organization: operations on outlines and subjective contours.

PubMed

Peterson, M A; Gibson, B S

1994-11-01

In previous research, replicated here, we found that some object recognition processes influence figure-ground organization. We have proposed that these object recognition processes operate on edges (or contours) detected early in visual processing, rather than on regions. Consistent with this proposal, influences from object recognition on figure-ground organization were previously observed in both pictures and stereograms depicting regions of different luminance, but not in random-dot stereograms, where edges arise late in processing (Peterson & Gibson, 1993). In the present experiments, we examined whether or not two other types of contours--outlines and subjective contours--enable object recognition influences on figure-ground organization. For both types of contours we observed a pattern of effects similar to that originally obtained with luminance edges. The results of these experiments are valuable for distinguishing between alternative views of the mechanisms mediating object recognition influences on figure-ground organization. In addition, in both Experiments 1 and 2, fixated regions were seen as figure longer than nonfixated regions, suggesting that fixation location must be included among the variables relevant to figure-ground organization.

Design study and performance analysis of a high-speed multistage variable-geometry fan for a variable cycle engine

NASA Technical Reports Server (NTRS)

Sullivan, T. J.; Parker, D. E.

1979-01-01

A design technology study was performed to identify a high speed, multistage, variable geometry fan configuration capable of achieving wide flow modulation with near optimum efficiency at the important operating condition. A parametric screening study of the front and rear block fans was conducted in which the influence of major fan design features on weight and efficiency was determined. Key design parameters were varied systematically to determine the fan configuration most suited for a double bypass, variable cycle engine. Two and three stage fans were considered for the front block. A single stage, core driven fan was studied for the rear block. Variable geometry concepts were evaluated to provide near optimum off design performance. A detailed aerodynamic design and a preliminary mechanical design were carried out for the selected fan configuration. Performance predictions were made for the front and rear block fans.

Experimental investigation of a variable speed constant frequency electric generating system from a utility perspective

NASA Technical Reports Server (NTRS)

Herrera, J. I.; Reddoch, T. W.; Lawler, J. S.

1985-01-01

As efforts are accelerated to improve the overall capability and performance of wind electric systems, increased attention to variable speed configurations has developed. A number of potentially viable configurations have emerged. Various attributes of variable speed systems need to be carefully tested to evaluate their performance from the utility points of view. With this purpose, the NASA experimental variable speed constant frequency (VSCF) system has been tested. In order to determine the usefulness of these systems in utility applications, tests are required to resolve issues fundamental to electric utility systems. Legitimate questions exist regarding how variable speed generators will influence the performance of electric utility systems; therefore, tests from a utility perspective, have been performed on the VSCF system and an induction generator at an operating power level of 30 kW on a system rated at 200 kVA and 0.8 power factor.

Analysis of Cyclic Variability of Heat Release for High-EGR GDI Engine Operation with Observations on Implications for Effective Control

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kaul, Brian C; Wagner, Robert M; Green Jr, Johney Boyd

2013-01-01

Operation of spark-ignition (SI) engines with high levels of charge dilution through exhaust gas recirculation (EGR) achieves significant engine efficiency gains while maintaining stoichiometric operation for compatibility with three-way catalysts. Dilution levels, however, are limited by cyclic variability-including significant numbers of misfires-that becomes more pronounced with increasing dilution. This variability has been shown to have both stochastic and deterministic components. Stochastic effects include turbulence, mixing variations, and the like, while the deterministic effect is primarily due to the nonlinear dependence of flame propagation rates and ignition characteristics on the charge composition, which is influenced by the composition of residual gasesmore » from prior cycles. The presence of determinism implies that an increased understanding the dynamics of such systems could lead to effective control approaches that allow operation near the edge of stability, effectively extending the dilution limit. This nonlinear dependence has been characterized previously for homogeneous charge, port fuel-injected (PFI) SI engines operating fuel-lean as well as with inert diluents such as bottled N2 gas. In this paper, cyclic dispersion in a modern boosted gasoline direct injection (GDI) engine using a cooled external EGR loop is examined, and the potential for improvement with effective control is evaluated through the use of symbol sequence statistics and other techniques from chaos theory. Observations related to the potential implications of these results for control approaches that could effectively enable engine operation at the edge of combustion stability are noted.« less

Measurement of strains at high temperatures by means of a portable holographic moire camera

NASA Astrophysics Data System (ADS)

Sciammarella, C. A.; Bhat, G.; Shao, Y.

Electronic holographic moire is utilized to measure strains at temperatures up to 1000 C. A CW laser operating at 50 mW and at the wavelength of 632.8 nm is used to illuminate the objects under study. The main variables influencing the fringe patterns visibility are discussed and measurements are performed to obtain the values of these variables in the performed experiments. The coefficient of expansion of an alloy is measured at temperatures ranging from 797 C to 986 C. Excellent agreement is found between the measured values and those provided by the manufacturer.

Measurement of strains at high temperatures by means of a portable holographic moire camera

NASA Technical Reports Server (NTRS)

Sciammarella, C. A.; Bhat, G.; Shao, Y.

1989-01-01

Electronic holographic moire is utilized to measure strains at temperatures up to 1000 C. A CW laser operating at 50 mW and at the wavelength of 632.8 nm is used to illuminate the objects under study. The main variables influencing the fringe patterns visibility are discussed and measurements are performed to obtain the values of these variables in the performed experiments. The coefficient of expansion of an alloy is measured at temperatures ranging from 797 C to 986 C. Excellent agreement is found between the measured values and those provided by the manufacturer.

The number of operations required for completing breast reconstruction.

PubMed

Eom, Jin Sup; Kobayashi, Mark Robert; Paydar, Keyianoosh; Wirth, Garrett A; Evans, Gregory R D

2014-10-01

Breast reconstruction often requires multiple surgeries, which demands additional expense and time and is often contrary to the patient's expectation. The aim of this study was to review the number of operations that were needed for completion of breast reconstruction and to determine patient and clinical factors that influenced this number. We retrospectively reviewed the medical records of 254 cases of breast reconstructions (in 185 patients) that were performed between February 2005 and August 2009. We investigated the numbers of operations that were performed for individual case of breast reconstruction and analyzed the influence of variable factors. The purpose of the additional operations was also analyzed. The mean number of operations per breast was 2.37 (range, 1-9). The mean number of operations for mound creation was 2.24. Factors associated with an increased number of operation were use of an implant, contralateral symmetrization, complications, and nipple reconstruction. Considering the reconstruction method, either the use of a primary implant or the use of free abdominal tissue transfer demonstrated fewer surgeries than the use of an expander implant, and the number of operations using free transverse rectus abdominis musculocutaneous or deep inferior epigastric perforator flaps was less than the number of operations using pedicled transverse rectus abdominis musculocutaneous flaps. These data will aid in planning breast reconstruction surgery and will enable patients to be more informed regarding the likelihood of multiple surgeries.

Valorisation of waste tyre by pyrolysis in a moving bed reactor.

PubMed

Aylón, E; Fernández-Colino, A; Murillo, R; Navarro, M V; García, T; Mastral, A M

2010-07-01

The aim of this work is to assess the behaviour of a moving bed reactor, based on a screw transporter design, in waste tyre pyrolysis under several experimental conditions. Waste tyre represents a significant problem in developed countries and it is necessary to develop new technology that could easily process big amounts of this potentially raw material. In this work, the influence of the main pyrolysis process variables (temperature, solid residence time, mass flow rate and inert gas flow) has been studied by a thorough analysis of product yields and properties. It has been found that regardless the process operational parameters, a total waste tyre devolatilisation is achieved, producing a pyrolytic carbon black with a volatile matter content under 5 wt.%. In addition, it has been proven that, in the range studied, the most influencing process variables are temperature and solid mass flow rate, mainly because both variables modify the gas residence time inside the reactor. In addition, it has been found that the modification of these variables affects to the chemical properties of the products. This fact is mainly associated to the different cracking reaction of the primary pyrolysis products. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

Fault detection of helicopter gearboxes using the multi-valued influence matrix method

NASA Technical Reports Server (NTRS)

Chin, Hsinyung; Danai, Kourosh; Lewicki, David G.

1993-01-01

In this paper we investigate the effectiveness of a pattern classifying fault detection system that is designed to cope with the variability of fault signatures inherent in helicopter gearboxes. For detection, the measurements are monitored on-line and flagged upon the detection of abnormalities, so that they can be attributed to a faulty or normal case. As such, the detection system is composed of two components, a quantization matrix to flag the measurements, and a multi-valued influence matrix (MVIM) that represents the behavior of measurements during normal operation and at fault instances. Both the quantization matrix and influence matrix are tuned during a training session so as to minimize the error in detection. To demonstrate the effectiveness of this detection system, it was applied to vibration measurements collected from a helicopter gearbox during normal operation and at various fault instances. The results indicate that the MVIM method provides excellent results when the full range of faults effects on the measurements are included in the training set.

Teaching the Surgical Craft: Surgery Residents Perception of the Operating Theater Educational Environment in a Tertiary Institution in Nigeria

PubMed Central

Ibrahim, Abdulrasheed; Delia, Ibrahim Z; Edaigbini, Sunday A; Abubakar, Amina; Dahiru, Ismail L; Lawal, Zakari Y

2013-01-01

Background: The transformation of a surgical trainee into a surgeon is strongly influenced by the quality of teaching in the operating theater. This study investigates the perceptions of residents about the educational environment of the operating theater and identifies variables that may improve the operating theater education of our trainees. Materials and Methods: Residents in the department of surgery anonymously evaluated teaching in the operating room using the operating theater education environment measure. The residents evaluated 33 variables that might have an impact on their surgical skills within the operating theater. The variables were grouped into four subscales; teaching and training, learning opportunities, operating theater atmosphere and workload/supervision/support. Differences between male and female residents and junior and senior registrars were assessed using Mann-Whitney test. Statistical analysis was completed with the statistics package for the social sciences version 17. Results: A total of 33 residents were participated in this study. Twenty nine (88%) males and 4 (12%) females. 30 (90%) were junior registrars. The mean total score was 67.5%. Operating theater atmosphere subscale had the highest score of 79.2% while workload/supervision/support subscale had the least score of 48.3%. There were significant differences between male and female resident's perception of workload/supervision/support P < 0.05; however, there was no significant differences in junior registrar versus senior registrar's perception of the education environment in all the subscales P > 0.05. Conclusion: This study has shown a satisfactory teaching environment based on the existing local realities of means, resources and tools and highlighted the need for improvement in workload/supervision/support in our institution. An acceptable learning environment in the operating theatre will produce surgeons that are technically competent to bridge the gap in the enormous unmet need for surgical care in Nigeria. PMID:24497753

Impact of some field factors on inhalation exposure levels to bitumen emissions during road paving operations.

PubMed

Deygout, François; Auburtin, Guy

2015-03-01

Variability in occupational exposure levels to bitumen emissions has been observed during road paving operations. This is due to recurrent field factors impacting the level of exposure experienced by workers during paving. The present study was undertaken in order to quantify the impact of such factors. Pre-identified variables currently encountered in the field were monitored and recorded during paving surveys, and were conducted randomly covering current applications performed by road crews. Multivariate variance analysis and regressions were then used on computerized field data. The statistical investigations were limited due to the relatively small size of the study (36 data). Nevertheless, the particular use of the step-wise regression tool enabled the quantification of the impact of several predictors despite the existing collinearity between variables. The two bitumen organic fractions (particulates and volatiles) are associated with different field factors. The process conditions (machinery used and delivery temperature) have a significant impact on the production of airborne particulates and explain up to 44% of variability. This confirms the outcomes described by previous studies. The influence of the production factors is limited though, and should be complemented by studying factors involving the worker such as work style and the mix of tasks. The residual volatile compounds, being part of the bituminous binder and released during paving operations, control the volatile emissions; 73% of the encountered field variability is explained by the composition of the bitumen batch. © The Author 2014. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

The role of non-financial performance measures in predicting hospital financial performance: the case of for-profit system hospitals.

PubMed

Vélez-González, Heltie; Pradhan, Rohit; Weech-Maldonado, Robert

2011-01-01

Non-financial measures have found increasing acceptance in the business world--however, their application in the health care industry remains limited. The purpose of this article is to understand the influence of non-financial measures (efficiency, productivity, and quality) on the financial performance of for-profit system hospitals. The sample consists of 499 for-profit system hospitals in the United States from 1999 to 2002. Data analyzed include the American Hospital Association's Annual Survey, Medicare Cost Reports, Joint Commission's quality scores, and the Centers for Medicare & Medicaid Services' Hospital Case Mix Index. Dependent variables consist of financial measures (operating and total margins), while independent variables include measures of efficiency, productivity, and quality. Our results suggest the influence of non-financial performance measures on financial performance; occupancy rate positively influences financial performance while greater labor intensity may have negative implications for financial performance. In addition, we show that quality positively influences financial performance thereby offering a potential business case for quality. This result has important managerial and policy implications as it may incentivize capital and human resource investments required to improve hospital quality of care.

What factors influence attending surgeon decisions about resident autonomy in the operating room?

PubMed

Williams, Reed G; George, Brian C; Meyerson, Shari L; Bohnen, Jordan D; Dunnington, Gary L; Schuller, Mary C; Torbeck, Laura; Mullen, John T; Auyang, Edward; Chipman, Jeffrey G; Choi, Jennifer; Choti, Michael; Endean, Eric; Foley, Eugene F; Mandell, Samuel; Meier, Andreas; Smink, Douglas S; Terhune, Kyla P; Wise, Paul; DaRosa, Debra; Soper, Nathaniel; Zwischenberger, Joseph B; Lillemoe, Keith D; Fryer, Jonathan P

2017-12-01

Educating residents in the operating room requires balancing patient safety, operating room efficiency demands, and resident learning needs. This study explores 4 factors that influence the amount of autonomy supervising surgeons afford to residents. We evaluated 7,297 operations performed by 487 general surgery residents and evaluated by 424 supervising surgeons from 14 training programs. The primary outcome measure was supervising surgeon autonomy granted to the resident during the operative procedure. Predictor variables included resident performance on that case, supervising surgeon history with granting autonomy, resident training level, and case difficulty. Resident performance was the strongest predictor of autonomy granted. Typical autonomy by supervising surgeon was the second most important predictor. Each additional factor led to a smaller but still significant improvement in ability to predict the supervising surgeon's autonomy decision. The 4 factors together accounted for 54% of decision variance (r = 0.74). Residents' operative performance in each case was the strongest predictor of how much autonomy was allowed in that case. Typical autonomy granted by the supervising surgeon, the second most important predictor, is unrelated to resident proficiency and warrants efforts to ensure that residents perform each procedure with many different supervisors. Copyright © 2017 Elsevier Inc. All rights reserved.

Psychologische Operaties: de theorie van Gedragsbeinvloeding (Psychological Operations: The Theory of Behavioral Influence)

DTIC Science & Technology

2006-08-01

for pursuing. Journal of Personality and Social Psychology, 87, 23-37. Ajzen , I . & Fishbein , M . (1970). The prediction of behavior from attitudinal and...normative variables. Journal of Experimental Social Psychology, 6, 466-487. Ajzen , I . & Fishbein , M . (1980). Understanding attitudes and predicting...theory of cognitive dissonance. Evanston, IL: Row, Peterson. Fishbein , M . & Ajzen , I . (1975). Belief, attitude, intention, and behavior: An introduction

The analysis of waste treatment methods and managerial skills towards the effectiveness of CO2 emmissions (an ex post facto study at TPA Bantar Gebang Bekasi)

NASA Astrophysics Data System (ADS)

Ria Rajagukguk, Jenni; Siagian, Lestina

2017-09-01

In the last three years, Java Island produces 29.413.336 m3/year of waste, coming from settlement (house hold) and non-settlement waste. Recently, this waste is managed with conventional technology, composting and recycling. Based on law No. 18 of 2008 on Waste Management, Chapter III Article 5, it is firmly stated that the government and regional governments are responsible for ensuring proper and environmentally sound waste management in accordance with the objectives. The observation of managerial skills is highly needed to investigate the operation of waste management at TPA Bantar Gebang towards the effectiveness of CO2 emissions.The problems are (1)Whether there is any influence between the method of waste management through Biogas Technology to the effectiveness of CO2 emissions. (2) Whether there is any influence between managerial skills to effectiveness of CO2 emission. (3) Whether there is any simultaneous influence between waste management method and managerial skill to CO2 emission effectiveness and (4) how is the method of waste management. Quantitative and egineering method were used to process the data.Biogas Technology variables and Managerial Skill are simultaneously and significantly influenced to CO2 Emission Effectiveness, this is based on Fh > Ft value of 168,453 > 3.072467) and its significance is 0.000 < 0,05. Then Ho was rejected and Ha was accepted which means that variable of Managerial Skill have influence or very big influence to Effeciveness of CO2 Emission, Correlation coefficient value 94,1% which means there is very strong relation between variable of Biogas Technology, Managerial Skill to Effectiveness of CO2 emission. Then Technology management through Biogas Technology is anaerobic biology.

Switching between simple cognitive tasks: the interaction of top-down and bottom-up factors

NASA Technical Reports Server (NTRS)

Ruthruff, E.; Remington, R. W.; Johnston, J. C.

2001-01-01

How do top-down factors (e.g., task expectancy) and bottom-up factors (e.g., task recency) interact to produce an overall level of task readiness? This question was addressed by factorially manipulating task expectancy and task repetition in a task-switching paradigm. The effects of expectancy and repetition on response time tended to interact underadditively, but only because the traditional binary task-repetition variable lumps together all switch trials, ignoring variation in task lag. When the task-recency variable was scaled continuously, all 4 experiments instead showed additivity between expectancy and recency. The results indicated that expectancy and recency influence different stages of mental processing. One specific possibility (the configuration-execution model) is that task expectancy affects the time required to configure upcoming central operations, whereas task recency affects the time required to actually execute those central operations.

Simulation of drive of mechanisms, working in specific conditions

NASA Astrophysics Data System (ADS)

Ivanovskaya, A. V.; Rybak, A. T.

2018-05-01

This paper presents a method for determining the dynamic loads on the lifting actuator device other than the conventional methods, for example, ship windlass. For such devices, the operation of their drives is typical under special conditions: different environments, the influence of hydrometeorological factors, a high level of vibration, variability of loading, etc. Hoisting devices working in such conditions are not considered in the standard; however, relevant studies concern permissible parameters of the drive devices of this kind. As an example, the article studied the work deck lifting devices - windlass. To construct a model, the windlass is represented by a rod of the variable cross-section. As a result, a mathematical model of the longitudinal oscillations of such rod is obtained. Analytic dependencies have also been obtained to determine the natural frequencies of the lowest forms of oscillations, which are necessary and are the basis for evaluating the parameters of operation of this type of the device.

Improved methods for the measurement and modeling of PV module and system performance for all operating conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

King, D.L.

1995-11-01

The objective of this work was to develop improved performance model for modules and systems for for all operating conditions for use in module specifications, system and BOS component design, and system rating or monitoring. The approach taken was to identify and quantify the influence of dominant factors of solar irradiance, cell temperature, angle-of-incidence; and solar spectrum; use outdoor test procedures to separate the effects of electrical, thermal, and optical performance; use fundamental cell characteristics to improve analysis; and combine factors in simple model using the common variables.

Large and local-scale influences on physical and chemical characteristics of coastal waters of Western Europe during winter

NASA Astrophysics Data System (ADS)

Tréguer, Paul; Goberville, Eric; Barrier, Nicolas; L'Helguen, Stéphane; Morin, Pascal; Bozec, Yann; Rimmelin-Maury, Peggy; Czamanski, Marie; Grossteffan, Emilie; Cariou, Thierry; Répécaud, Michel; Quéméner, Loic

2014-11-01

There is now a strong scientific consensus that coastal marine systems of Western Europe are highly sensitive to the combined effects of natural climate variability and anthropogenic climate change. However, it still remains challenging to assess the spatial and temporal scales at which climate influence operates. While large-scale hydro-climatic indices, such as the North Atlantic Oscillation (NAO) or the East Atlantic Pattern (EAP) and the weather regimes such as the Atlantic Ridge (AR), are known to be relevant predictors of physical processes, changes in coastal waters can also be related to local hydro-meteorological and geochemical forcing. Here, we study the temporal variability of physical and chemical characteristics of coastal waters located at about 48°N over the period 1998-2013 using (1) sea surface temperature, (2) sea surface salinity and (3) nutrient concentration observations for two coastal sites located at the outlet of the Bay of Brest and off Roscoff, (4) river discharges of the major tributaries close to these two sites and (5) regional and local precipitation data over the region of interest. Focusing on the winter months, we characterize the physical and chemical variability of these coastal waters and document changes in both precipitation and river runoffs. Our study reveals that variability in coastal waters is connected to the large-scale North Atlantic atmospheric circulation but is also partly explained by local river influences. Indeed, while the NAO is strongly related to changes in sea surface temperature at the Brest and Roscoff sites, the EAP and the AR have a major influence on precipitations, which in turn modulate river discharges that impact sea surface salinity at the scale of the two coastal stations.

[Operational costs and control of performance in surgical clinics between marketing and planning economics. Risk or perhaps quadrature of the circle].

PubMed

Kraus, T W; Weber, W; Mieth, M; Funk, H; Klar, E; Herfarth, C

2000-03-01

Surgical hospitals can be seen as operational or even industrial production systems. Doctors have a major impact on both medical performance and costs. For active participation in the management process, knowledge of industrial controlling mechanisms is required. German hospitals currently receive no procedure-related financial revenues, such as prices or tariffs for defined medical treatment activities. Maximum clinical revenues are, furthermore, limited by principles of planned economy and can be increased only slightly by greater medical performance. Costs are the only target that can be autonomously influenced by the management. Operative controlling in hospitals aims at horizontal and vertical coordination of subunits and decentralization of process regulations. Hospital medical performance is not clearly defined, its quantitative measurement very problematic. Process-orientated clinical activities are not taken into account. A high percentage of hospital costs are fixed and can be influenced only by major structural interventions in the long term. Variable costs are primarily dependent on the quantity of clinical activities, but also heavily influenced by patient structure (comorbidity and risk profile). The various forms of industrial cost calculations, such as internal budgeting, internal markets or flexible plan-cost balancing, cannot be directly applied in hospital management. Based on these analyses, current operational concepts and strategic trends are listed to describe cost-management options in hospitals with focus on the German health reforms.

Impairment of wound healing after operative treatment of mandibular fractures, and the influence of dexamethasone.

PubMed

Snäll, Johanna; Kormi, Eeva; Lindqvist, Christian; Suominen, Anna Liisa; Mesimäki, Karri; Törnwall, Jyrki; Thorén, Hanna

2013-12-01

Our aim was to clarify the incidence of impaired wound healing after open reduction and ostheosynthesis of mandibular fractures, and to find out whether the use of dexamethasone during the operation increased the risk. Patients were drawn from a larger group of healthy adult dentate patients who had participated in a single-blind, randomised study, the aim of which was to clarify the benefits of operative dexamethasone after treatment of facial fractures. The present analysis comprised 41 patients who had had open reduction and fixation of mandibular fractures with titanium miniplates and monocortical screws through one or 2 intraoral approaches. The outcome variable was impaired healing of the wound. The primary predictive variable was the perioperative use of dexamethasone; other potential predictive variables were age, sex, smoking habit, type of fracture, delay in treatment, and duration of operation. Wound healing was impaired in 13/41 patients (32%) (13/53 of all fractures). The incidence among patients who were given dexamethasone and those who were not did not differ significantly. Only age over 25 was significantly associated with delayed healing (p=0.02). The use of dexamethasone 30 mg perioperatively did not significantly increase the risk of impaired wound healing in healthy patients with clinically uninfected mandibular fractures fixed with titanium miniplates through an intraoral approach. Older age is a significant predictor of impaired healing, which emphasises the importance of thorough anti-infective care in these patients during and after the operation. Copyright © 2013 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Forest management under changing climate conditions: Is timing a tool for Sustainable Forest Management? Relevant questions for research development

NASA Astrophysics Data System (ADS)

D'Aprile, Fabrizio; McShane, Paul; Tapper, Nigel

2013-04-01

Change of climate conditions influence energy fluxes applicable to forest ecosystems. These affect cycles of nutrients and materials, primary productivity of the ecosystem, biodiversity, ecological functionality and, consequently, carbon equilibria of the forest ecosystem. Temporal factors influence physical, biological, ecological, and climatic processes and functions. For example, seasonality, cycles, periodicity, and trends in climate variables; tree growth, forest growth, and forest metabolic activities (i.e., photosynthesis and respiration) are commonly known to be time-related. In tropical forests, the impacts of changing climate conditions may exceed temperature and/or precipitation thresholds critical to forest tree growth or health. Historically, forest management emphasises growth rates and financial returns as affected by species and site. Until recently, the influence of climate variability on growth dynamics has not been influential in forest planning and management. Under this system, especially in climatic and forest regions where most of species are stenoecious, periodical wood harvesting may occur in any phase of growth (increasing, decreasing, peak, and trough). This scenario presents four main situations: a) harvesting occurs when the rate of growth is decreasing: future productivity is damaged; the minimum biomass capital may be altered, and CO2 storage is negatively affected; b) harvesting occurs during a trough of the rate of growth: the minimum biomass capital necessary to preserve the resilience of the forest is damaged; the damage can be temporary (decades) or permanent; CO2 storage capacity is deficient - which may be read as an indirect emission of CO2 since the balance appears negative; c) harvesting occurs when the rate of growth is increasing: the planned wood mass can be used without compromising the resilience and recovery of the forest; CO2 storage remains increasing; d) harvesting occurs during a peak period of growth: the wood mass harvested can be even higher than planned, and the rate of CO2 storage can be above the average. A real risk for SFM under changing climatic conditions is that negative effects may be amplified; critical thresholds of temperature and/or rainfall for tree growth and stress may be exceeded with impacts on growth response, resilience, and CO2 balance that are not completely known. Furthermore, temporal changes in silvicultural and harvesting operations may lead to increased carbon emissions. Under this scenario and the consequent risks to SFM forestry operations should be planned or scheduled in periods when climate variables influencing tree growth and stress are within the relative thresholds. In this way, silvicultural operations and harvesting are going to be optimised to climate variability and forest growth responses, rather than just forest timber production.

Stronger Working Memory Reduces Sexual Risk taking in Adolescents, Even After Controlling for Parental Influences

PubMed Central

Khurana, Atika; Romer, Daniel; Betancourt, Laura M.; Brodsky, Nancy L.; Giannetta, Joan M.; Hurt, Hallam

2015-01-01

This study examined the prospective influence of adolescent working memory (WM) on changes in impulsivity and sexual risk taking and assessed whether this relation could be explained by confounding effects of parental influences. Data from 360 community adolescents (Mage=13.5±0.95years; 52% female; 56% non-Hispanic White; low-mid SES; recruited from Philadelphia area in 2004–2005) were analyzed using structural equation modeling to predict changes in impulsivity and sexual risk taking over a two-year follow-up, using baseline assessments of WM, parental monitoring, parental involvement, and socioeconomic status. Stronger WM predicted reduced involvement in sexual risk taking at follow-up, effects channeled through changes in impulsivity dimensions of ‘acting without thinking’ and ‘inability to delay gratification’. Parental variables had a protective influence on adolescent impulsivity and risk involvement, but the effects of WM operated independently of parental influences. PMID:26081926

The factors influencing the decision making of operative treatment for proximal humeral fractures.

PubMed

Hageman, Michiel G J S; Jayakumar, Prakash; King, John D; Guitton, Thierry G; Doornberg, Job N; Ring, David

2015-01-01

The factors influencing the decision making of operative treatment for fractures of the proximal humerus are debated. We hypothesized that there is no difference in treatment recommendations between surgeons shown radiographs alone and those shown radiographs and patient information. Secondarily, we addressed (1) factors associated with a recommendation for operative treatment, (2) factors associated with recommendation for arthroplasty, (3) concordance with the recommendations of the treating surgeons, and (4) factors affecting the inter-rater reliability of treatment recommendations. A total of 238 surgeons of the Science of Variation Group rated 40 radiographs of patients with proximal humerus fractures. Participants were randomized to receive information about the patient and mechanism of injury. The response variables included the choice of treatment (operative vs nonoperative) and the percentage of matches with the actual treatment. Participants who received patient information recommended operative treatment less than those who received no information. The patient information that had the greatest influence on treatment recommendations included age (55%) and fracture mechanism (32%). The only other factor associated with a recommendation for operative treatment was region of practice. There was no significant difference between participants who were and were not provided with information regarding agreement with the actual treatment (operative vs nonoperative) provided by the treating surgeon. Patient information-older age in particular-is associated with a higher likelihood of recommending nonoperative treatment than radiographs alone. Clinical information did not improve agreement of the Science of Variation Group with the actual treatment or the generally poor interobserver agreement on treatment recommendations. Copyright © 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Influence plots for LASSO

DOE PAGES

Jang, Dae -Heung; Anderson-Cook, Christine Michaela

2016-11-22

With many predictors in regression, fitting the full model can induce multicollinearity problems. Least Absolute Shrinkage and Selection Operation (LASSO) is useful when the effects of many explanatory variables are sparse in a high-dimensional dataset. Influential points can have a disproportionate impact on the estimated values of model parameters. Here, this paper describes a new influence plot that can be used to increase understanding of the contributions of individual observations and the robustness of results. This can serve as a complement to other regression diagnostics techniques in the LASSO regression setting. Using this influence plot, we can find influential pointsmore » and their impact on shrinkage of model parameters and model selection. Lastly, we provide two examples to illustrate the methods.« less

Influence plots for LASSO

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jang, Dae -Heung; Anderson-Cook, Christine Michaela

With many predictors in regression, fitting the full model can induce multicollinearity problems. Least Absolute Shrinkage and Selection Operation (LASSO) is useful when the effects of many explanatory variables are sparse in a high-dimensional dataset. Influential points can have a disproportionate impact on the estimated values of model parameters. Here, this paper describes a new influence plot that can be used to increase understanding of the contributions of individual observations and the robustness of results. This can serve as a complement to other regression diagnostics techniques in the LASSO regression setting. Using this influence plot, we can find influential pointsmore » and their impact on shrinkage of model parameters and model selection. Lastly, we provide two examples to illustrate the methods.« less

Influence of operating conditions on the air gasification of dry refinery sludge in updraft gasifier

NASA Astrophysics Data System (ADS)

Ahmed, R.; Sinnathambi, C. M.

2013-06-01

In the present work, details of the equilibrium modeling of dry refinery sludge (DRS) are presented using ASPEN PLUS Simulator in updraft gasifier. Due to lack of available information in the open journal on refinery sludge gasification using updraft gasifier, an evaluate for its optimum conditions on gasification is presented in this paper. For this purpose a Taguchi Orthogonal array design, statistical software is applied to find optimum conditions for DRS gasification. The goal is to identify the most significant process variable in DRS gasification conditions. The process variables include; oxidation zone temperature, equivalent ratio, operating pressure will be simulated and examined. Attention was focused on the effect of optimum operating conditions on the gas composition of H2 and CO (desirable) and CO2 (undesirable) in terms of mass fraction. From our results and finding it can be concluded that the syngas (H2 & CO) yield in term of mass fraction favors high oxidation zone temperature and at atmospheric pressure while CO2 acid gas favor at a high level of equivalent ratio as well as air flow rate favoring towards complete combustion.

Time-delay signature of chaos in 1550 nm VCSELs with variable-polarization FBG feedback.

PubMed

Li, Yan; Wu, Zheng-Mao; Zhong, Zhu-Qiang; Yang, Xian-Jie; Mao, Song; Xia, Guang-Qiong

2014-08-11

Based on the framework of spin-flip model (SFM), the output characteristics of a 1550 nm vertical-cavity surface-emitting laser (VCSEL) subject to variable-polarization fiber Bragg grating (FBG) feedback (VPFBGF) have been investigated. With the aid of the self-correlation function (SF) and the permutation entropy (PE) function, the time-delay signature (TDS) of chaos in the VPFBGF-VCSEL is evaluated, and then the influences of the operation parameters on the TDS of chaos are analyzed. The results show that the TDS of chaos can be suppressed efficiently through selecting suitable coupling coefficient and feedback rate of the FBG, and is weaker than that of chaos generated by traditional variable-polarization mirror feedback VCSELs (VPMF-VCSELs) or polarization-preserved FBG feedback VCSELs (PPFBGF-VCSELs).

Determining vehicle operating speed and lateral position along horizontal curves using linear mixed-effects models.

PubMed

Fitzsimmons, Eric J; Kvam, Vanessa; Souleyrette, Reginald R; Nambisan, Shashi S; Bonett, Douglas G

2013-01-01

Despite recent improvements in highway safety in the United States, serious crashes on curves remain a significant problem. To assist in better understanding causal factors leading to this problem, this article presents and demonstrates a methodology for collection and analysis of vehicle trajectory and speed data for rural and urban curves using Z-configured road tubes. For a large number of vehicle observations at 2 horizontal curves located in Dexter and Ames, Iowa, the article develops vehicle speed and lateral position prediction models for multiple points along these curves. Linear mixed-effects models were used to predict vehicle lateral position and speed along the curves as explained by operational, vehicle, and environmental variables. Behavior was visually represented for an identified subset of "risky" drivers. Linear mixed-effect regression models provided the means to predict vehicle speed and lateral position while taking into account repeated observations of the same vehicle along horizontal curves. Speed and lateral position at point of entry were observed to influence trajectory and speed profiles. Rural horizontal curve site models are presented that indicate that the following variables were significant and influenced both vehicle speed and lateral position: time of day, direction of travel (inside or outside lane), and type of vehicle.

A Modeling Investigation of Thermal and Strain Induced Recovery and Nonlinear Hardening in Potential Based Viscoplasticity

NASA Technical Reports Server (NTRS)

Arnold, S. M.; Saleeb, A. F.; Wilt, T. E.

1993-01-01

Specific forms for both the Gibb's and the complementary dissipation potentials were chosen such that a complete potential based multiaxial, isothermal, viscoplastic model was obtained. This model in general possesses three internal state variables (two scalars associated with dislocation density and one tensor associated with dislocation motion) both thermal and dynamic recovery mechanisms, and nonlinear kinematic hardening. This general model, although possessing associated flow and evolutionary laws, is shown to emulate three distinct classes of theories found in the literature, by modification of the driving threshold function F. A parametric study was performed on a specialized nondimensional multiaxial form containing only a single tensorial internal state variable (i.e., internal stress). The study was conducted with the idea of examining the impact of including a strain-induced recovery mechanism and the compliance operator, derived from the Gibb's potential, on the uniaxial and multiaxial response. One important finding was that inclusion of strain recovery provided the needed flexibility in modeling stress-strain and creep response of metals at low homologous temperatures, without adversely affecting the high temperature response. Furthermore, for nonproportional loading paths, the inclusion of the compliance operator had a significant influence on the multiaxial response, but had no influence on either uniaxial or proportional load histories.

Evaluation of anode (electro)catalytic materials for the direct borohydride fuel cell: Methods and benchmarks

NASA Astrophysics Data System (ADS)

Olu, Pierre-Yves; Job, Nathalie; Chatenet, Marian

2016-09-01

In this paper, different methods are discussed for the evaluation of the potential of a given catalyst, in view of an application as a direct borohydride fuel cell DBFC anode material. Characterizations results in DBFC configuration are notably analyzed at the light of important experimental variables which influence the performances of the DBFC. However, in many practical DBFC-oriented studies, these various experimental variables prevent one to isolate the influence of the anode catalyst on the cell performances. Thus, the electrochemical three-electrode cell is a widely-employed and useful tool to isolate the DBFC anode catalyst and to investigate its electrocatalytic activity towards the borohydride oxidation reaction (BOR) in the absence of other limitations. This article reviews selected results for different types of catalysts in electrochemical cell containing a sodium borohydride alkaline electrolyte. In particular, propositions of common experimental conditions and benchmarks are given for practical evaluation of the electrocatalytic activity towards the BOR in three-electrode cell configuration. The major issue of gaseous hydrogen generation and escape upon DBFC operation is also addressed through a comprehensive review of various results depending on the anode composition. At last, preliminary concerns are raised about the stability of potential anode catalysts upon DBFC operation.

Effects of Escitalopram on Autonomic Function in Posttraumatic Stress Disorder Among Veterans of Operations Enduring Freedom and Iraqi Freedom (OEF/OIF).

PubMed

Ramaswamy, Sriram; Selvaraj, Vithyalakshmi; Driscoll, David; Madabushi, Jayakrishna S; Bhatia, Subhash C; Yeragani, Vikram

2015-01-01

Posttraumatic stress disorder is a chronic, debilitating condition that has become a growing concern among combat veterans. Previous research suggests that posttraumatic stress disorder disrupts normal autonomic responding and may increase the risk of cardiovascular disease and mortality. Measures of heart rate variability and QT interval variability have been used extensively to characterize sympathetic and parasympathetic influences on heart rate in a variety of psychiatric populations. The objective of this study was to better understand the effects of pharmacological treatment on autonomic reactivity in posttraumatic stress disorder. A 12-week, Phase IV, prospective, open-label trial of escitalopram in veterans with combat-related posttraumatic stress disorder and comorbid depression. An outpatient mental health clinic at a Veterans Affairs Medical Center. Eleven male veterans of Operations Enduring Freedom and Iraqi Freedom diagnosed with posttraumatic stress disorder and comorbid depression. Autonomic reactivity was measured by examining heart rate variability and QT interval variability. Treatment safety and efficacy were also evaluated pre- and post-treatment. We observed a reduction in posttraumatic stress disorder and depression symptoms from pre- to post-treatment, and escitalopram was generally well tolerated in our sample. In addition, we observed a decrease in high frequency heart rate variability and an increase in QT variability, indicating a reduction in cardiac vagal function and heightened sympathetic activation. These findings suggest that escitalopram treatment in patients with posttraumatic stress disorder and depression can trigger changes in autonomic reactivity that may adversely impact cardiovascular health.

Spray-drying nanocapsules in presence of colloidal silica as drying auxiliary agent: formulation and process variables optimization using experimental designs.

PubMed

Tewa-Tagne, Patrice; Degobert, Ghania; Briançon, Stéphanie; Bordes, Claire; Gauvrit, Jean-Yves; Lanteri, Pierre; Fessi, Hatem

2007-04-01

Spray-drying process was used for the development of dried polymeric nanocapsules. The purpose of this research was to investigate the effects of formulation and process variables on the resulting powder characteristics in order to optimize them. Experimental designs were used in order to estimate the influence of formulation parameters (nanocapsules and silica concentrations) and process variables (inlet temperature, spray-flow air, feed flow rate and drying air flow rate) on spray-dried nanocapsules when using silica as drying auxiliary agent. The interactions among the formulation parameters and process variables were also studied. Responses analyzed for computing these effects and interactions were outlet temperature, moisture content, operation yield, particles size, and particulate density. Additional qualitative responses (particles morphology, powder behavior) were also considered. Nanocapsules and silica concentrations were the main factors influencing the yield, particulate density and particle size. In addition, they were concerned for the only significant interactions occurring among two different variables. None of the studied variables had major effect on the moisture content while the interaction between nanocapsules and silica in the feed was of first interest and determinant for both the qualitative and quantitative responses. The particles morphology depended on the feed formulation but was unaffected by the process conditions. This study demonstrated that drying nanocapsules using silica as auxiliary agent by spray drying process enables the obtaining of dried micronic particle size. The optimization of the process and the formulation variables resulted in a considerable improvement of product yield while minimizing the moisture content.

A feasibility study on the predictive emission monitoring system applied to the Hsinta power plant of Taiwan Power Company.

PubMed

Chien, T W; Chu, H; Hsu, W C; Tseng, T K; Hsu, C H; Chen, K Y

2003-08-01

The continuous emission monitoring system (CEMS) can monitor flue gas emissions continuously and instantaneously. However, it has the disadvantages of enormous cost, easily producing errors in sampling periods of bad weather, lagging response in variable ambient environments, and missing data in daily zero and span tests and maintenance. The concept of a predictive emission monitoring system (PEMS) is to use the operating parameters of combustion equipment through thermodynamic or statistical methods to construct a mathematic model that can predict emissions by a computer program. The goal of this study is to set up a PEMS in a gas-fired combined cycle power generation unit at the Hsinta station of Taiwan Power Co. The emissions to be monitored include nitrogen oxides (NOx) and oxygen (O2) in flue gas. The major variables of the predictive model were determined based on the combustion theory. The data of these variables then were analyzed to establish a regression model. From the regression results, the influences of these variables are discussed and the predicted values are compared with the CEMS data for accuracy. In addition, according to the cost information, the capital and operation and maintenance costs for a PEMS can be much lower than those for a CEMS.

Variables Associated With Return to Sport Following Anterior Cruciate Ligament Reconstruction: A Systematic Review

PubMed Central

Czuppon, Sylvia; Racette, Brad A.; Klein, Sandra E.; Harris-Hayes, Marcie

2014-01-01

Background As one of the purposes of anterior cruciate ligament reconstruction (ACLR) is to return athletes to their pre-injury activity level, it is critical to understand variables influencing return to sport. Associations between return to sport and variables representing knee impairment, function and psychological status have not been well studied in athletes following ACLR. Purpose The purpose of this review is to summarize the literature reporting on variables proposed to be associated with return to sport following anterior cruciate ligament reconstruction. Study Design Systematic Review Methods Medline, Embase, CINAHL and Cochrane databases were searched for articles published before November 2012. Articles included in this review met these criteria: 1) included patients with primary ACLR, 2) reported at least one knee impairment, function or psychological measure, 3) reported a return to sport measure and 4) analyzed the relationship between the measure and return to sport. Results Weak evidence existed in sixteen articles suggesting variables associated with return to sport included higher quadriceps strength, less effusion, less pain, greater tibial rotation, higher Marx Activity score, higher athletic confidence, higher pre-operative knee self-efficacy, lower kinesiophobia and higher pre-operative self-motivation. Conclusion Weak evidence supports an association between knee impairment, functional, and psychological variables and return to sport. Current return to sport guidelines should be updated to reflect all variables associated with return to sport. Utilizing evidence-based return to sport guidelines following ACLR may ensure athletes are physically and psychologically capable of sports participation, which may reduce re-injury rates and the need for subsequent surgery. PMID:24124040

Analytical variability of estimated platelet counts on canine blood smears.

PubMed

Paltrinieri, Saverio; Paciletti, Veronica; Zambarbieri, Jari

2018-06-04

The analytical variability of estimated platelet counts in dogs has not been reported. The purpose of this study was to assess the magnitude of analytical imprecision of platelet estimates and the possible impact of this imprecision on clinical decisions. Three independent observers counted the number of platelets in 3 different areas (LE = lateral edge; CM = central monolayer; FE = feathered edge) of 30 canine blood smears with different instrumental platelet counts. The coefficient of variation (CV) for each observer was calculated in different areas of each smear (intra-observer variability), among different regions of each smear (inter-area variability), and among different observers in each area (inter-observer variability). The influence of these variabilities on the classification of platelet estimates as adequate, increased, or decreased was also assessed. The CVs recorded in the different areas by each observer ranged from 8% to 88% and were negatively correlated (P < .001, r = -.65) with the mean number of platelets per field. The mean platelet number was significantly lower in the FE and significantly higher in the CM compared with the LE, but the magnitude of this difference varied with the operators. The concordance among operators regarding platelet estimates was fair (k = 0.36) to substantial (k = 0.71) depending on the area. The overall inter-area concordance was moderate (k = 0.59). Platelet estimates suffer from high variability that could lead to patient misclassification. Therefore, guidelines to standardize the platelet estimate are needed. © 2018 American Society for Veterinary Clinical Pathology.

Evaluation of losses in transmission of machinery for development of mineral deposits in conditions of variable load

NASA Astrophysics Data System (ADS)

Zvonarev, I. E.; Ivanov, S. L.

2017-10-01

The influence of individual elements of machines transmissions on the operation of the whole system is shown. The approach of determining the resource of operation of systems elements based on the energy theory is presented. The formulas for determining the total energy resource of the reducer are given. The influence of individual elements of the system on each other is indicated. The principle of researching the system by the method of equivalent circuits is substantiated. The weakest places of transmission (gears, bearing supports and shafts) are determined. A mathematical model of a mechanical transmission was developed. To test the adequacy of the mathematical model, the stand for obtaining experimental data was designed. The description of the stand and the principle of its operation are given. Experimental data are presented. A comparative analysis of modeling and experimental data is carried out and the adequacy of the developed mathematical model is proved. The principle of determining the resource of the system as a whole for the element with the minimal resource of work is suggested.

The importance of scale-dependent ravine characteristics on breeding-site selection by the Burrowing Parrot, Cyanoliseus patagonus

PubMed Central

Rios, Rodrigo S.; Vargas-Rodriguez, Renzo; Novoa-Jerez, Jose-Enrique; Squeo, Francisco A.

2017-01-01

In birds, the environmental variables and intrinsic characteristics of the nest have important fitness consequences through its influence on the selection of nesting sites. However, the extent to which these variables interact with variables that operate at the landscape scale, and whether there is a hierarchy among the different scales that influences nest-site selection, is unknown. This interaction could be crucial in burrowing birds, which depend heavily on the availability of suitable nesting locations. One representative of this group is the burrowing parrot, Cyanoliseus patagonus that breeds on specific ravines and forms large breeding colonies. At a particular site, breeding aggregations require the concentration of adequate environmental elements for cavity nesting, which are provided by within ravine characteristics. Therefore, intrinsic ravine characteristics should be more important in determining nest site selection compared to landscape level characteristics. Here, we assess this hypothesis by comparing the importance of ravine characteristics operating at different scales on nest-site selection and their interrelation with reproductive success. We quantified 12 characteristics of 105 ravines in their reproductive habitat. For each ravine we quantified morphological variables, distance to resources and disturbance as well as nest number and egg production in order to compare selected and non-selected ravines and determine the interrelationship among variables in explaining ravine differences. In addition, the number of nests and egg production for each reproductive ravine was related to ravine characteristics to assess their relation to reproductive success. We found significant differences between non-reproductive and reproductive ravines in both intrinsic and extrinsic characteristics. The multidimensional environmental gradient of variation between ravines, however, shows that differences are mainly related to intrinsic morphological characteristics followed by extrinsic variables associated to human disturbance. Likewise, within reproductive ravines, intrinsic characteristics are more strongly related to the number of nests. The probability of producing eggs, however, was related only to distance to roads and human settlements. Patterns suggest that C. patagonus mainly selects nesting sites based on intrinsic morphological characteristics of ravines. Scale differences in the importance of ravine characteristics could be a consequence of the particular orography of the breeding habitat. The arrangement of resources is associated to the location of the gullies rather than to individual ravines, determining the spatial availability and disposition of resources and disturbances. Thus, nest selection is influenced by intrinsic characteristics that maximize the fitness of individuals. Scaling in nest-selection is discussed under an optimality approach that partitions patch selection based on foraging theory. PMID:28462019

Digital image color analysis compared to direct dental CIE colorimeter assessment under different ambient conditions.

PubMed

Knösel, Michael; Attin, Rengin; Jung, Klaus; Brunner, Edgar; Kubein-Meesenburg, Dietmar; Attin, Thomas

2009-04-01

To evaluate the concordance and repeatability of two in vivo methods for dental color assessment and to clarify the influence of different ambient light conditions and subject's head position on the assessed color variables. Color assessments were performed by two examiners on 16 arbitrarily selected subjects under two different, standardized conditions of illumination and at two different standardized head angulations. CIE (L*a*b*) data for upper and lower central incisors were recorded in two different ways: (1) by an intra-oral contact dental colorimeter and (2) by processing digital images for performing color calculation using Adobe Photoshop software. The influence of the different ambient conditions on both methods, as well as the concordance of measurements was analyzed statistically using several mixed linear models. Ambient light as a single factor had no significant influence on maxillary L*, a* and b* values, but it did have an effect on mandible assessments. Head angulation variation resulted in significant L* value differences using the photo method. The operator had a significant influence on values a* and b* for the photo method and on a* values for the colorimeter method. In fully lit ambient condition, the operator had a significant influence on the segregated L*, a*, and b* values. With dimmed lights, head angulation became significant, but not the operator. Evaluation of segregated L* values was error prone in both methods. Comparing both methods, deltaE values did not exceed 2.85 units, indicating that color differences between methods and recorded under varying ambient conditions were well below the sensitivity of the naked eye.

Progressive Entrustment to Achieve Resident Autonomy in the Operating Room: A National Qualitative Study With General Surgery Faculty and Residents.

PubMed

Sandhu, Gurjit; Magas, Christopher P; Robinson, Adina B; Scally, Christopher P; Minter, Rebecca M

2017-06-01

The purpose of this study was to identify behaviors that faculty and residents exhibit during intraoperative interactions, which support or inhibit progressive entrustment leading to operative autonomy. In the operating room, a critical balance is sought between direct faculty supervision and appropriate increase in resident autonomy with indirect faculty supervision. Little is known regarding perspectives of faculty and residents about how attendings increasingly step back and safely delegate autonomy to trainees. Understanding the context in which these decisions are made is critical to achieving a safe strategy for imparting progressive responsibility. A qualitative study was undertaken from January 2014 to February 2015. Semistructured interviews were conducted with 37 faculty and 59 residents from 14 and 41 institutions, respectively. Participants were selected using stratified random sampling from general surgery residency programs across the United States to represent a range of university, university-affiliated, and community programs, and geographic regions. Audio recordings of interviews were transcribed, iteratively analyzed, and emergent themes identified. Six themes were identified as influencing progressive entrustment in the operating room: optimizing faculty intraoperative feedback; policies and regulations affecting role of resident in the operating room; flexible faculty teaching strategies; context-specific variables; leadership opportunities for resident in the case; and safe struggle for resident when appropriate. Perspectives of faculty and residents while overlapping were different in emphasis. Better understanding faculty-resident interactions, individual behaviors, contextual influences, and national regulations that influence intraoperative education have the potential to significantly affect progressive entrustment in training paradigms.

A systematic approach to evaluate parameter consistency in the inlet stream of source separated biowaste composting facilities: A case study in Colombia.

PubMed

Oviedo-Ocaña, E R; Torres-Lozada, P; Marmolejo-Rebellon, L F; Torres-López, W A; Dominguez, I; Komilis, D; Sánchez, A

2017-04-01

Biowaste is commonly the largest fraction of municipal solid waste (MSW) in developing countries. Although composting is an effective method to treat source separated biowaste (SSB), there are certain limitations in terms of operation, partly due to insufficient control to the variability of SSB quality, which affects process kinetics and product quality. This study assesses the variability of the SSB physicochemical quality in a composting facility located in a small town of Colombia, in which SSB collection was performed twice a week. Likewise, the influence of the SSB physicochemical variability on the variability of compost parameters was assessed. Parametric and non-parametric tests (i.e. Student's t-test and the Mann-Whitney test) showed no significant differences in the quality parameters of SSB among collection days, and therefore, it was unnecessary to establish specific operation and maintenance regulations for each collection day. Significant variability was found in eight of the twelve quality parameters analyzed in the inlet stream, with corresponding coefficients of variation (CV) higher than 23%. The CVs for the eight parameters analyzed in the final compost (i.e. pH, moisture, total organic carbon, total nitrogen, C/N ratio, total phosphorus, total potassium and ash) ranged from 9.6% to 49.4%, with significant variations in five of those parameters (CV>20%). The above indicate that variability in the inlet stream can affect the variability of the end-product. Results suggest the need to consider variability of the inlet stream in the performance of composting facilities to achieve a compost of consistent quality. Copyright © 2017 Elsevier Ltd. All rights reserved.

Financial implications of choice of dialysis type of the revised Medicare payment system: an economic analysis.

PubMed

Hornberger, John; Hirth, Richard A

2012-08-01

In 2011, the Medicare Improvements for Patients and Providers Act replaced the case-mix-adjusted composite payment system for Medicare outpatient dialysis facilities with a bundled end-stage renal disease prospective payment system (PPS). We assessed the economic implications for modality choice of the revised Medicare payment system. Microeconomic analyses. Patients eligible for dialysis in the United States. The perspective of this analysis is that of a financial administrator of a representative dialysis center in the United States. Data were obtained from the Medicare Payment Advisory Commission, the US Renal Data System, the DOPPS (Dialysis Outcomes and Practice Patterns Study) Practice Monitor, the US Bureau of Labor Statistics, and Medicare fee schedules. Recently implemented end-stage renal disease PPS versus the prior case-mix composite payment system. Medicare payment per month, center fixed and variable costs per month, net difference in revenue and variable costs (direct contribution), and net difference in revenue and total costs (operating margin). The direct contribution and operating margin for in-center hemodialysis and peritoneal dialysis are expected to be positive under the new bundled PPS. For Medicare fiscal intermediaries/administrators, paid treatments for home hemodialysis vary from 3.2 to more than 4.8 per week. The direct contribution and operating margin are expected to be negative for home hemodialysis if the number of paid treatments is similar between in-center and home hemodialysis; they are almost identical when the number of paid treatments increases for home hemodialysis by approximately 1 per week. Experience across centers and intermediaries/administrators may vary. Sensitivity analyses were conducted to assess the robustness of findings and determine which variables most influenced results. The new bundled PPS created a financial incentive for increased use of peritoneal dialysis. Use of home hemodialysis may be influenced by number of paid treatments per week. Copyright © 2012 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

Structural damage detection for in-service highway bridge under operational and environmental variability

NASA Astrophysics Data System (ADS)

Jin, Chenhao; Li, Jingcheng; Jang, Shinae; Sun, Xiaorong; Christenson, Richard

2015-03-01

Structural health monitoring has drawn significant attention in the past decades with numerous methodologies and applications for civil structural systems. Although many researchers have developed analytical and experimental damage detection algorithms through vibration-based methods, these methods are not widely accepted for practical structural systems because of their sensitivity to uncertain environmental and operational conditions. The primary environmental factor that influences the structural modal properties is temperature. The goal of this article is to analyze the natural frequency-temperature relationships and detect structural damage in the presence of operational and environmental variations using modal-based method. For this purpose, correlations between natural frequency and temperature are analyzed to select proper independent variables and inputs for the multiple linear regression model and neural network model. In order to capture the changes of natural frequency, confidence intervals to detect the damages for both models are generated. A long-term structural health monitoring system was installed on an in-service highway bridge located in Meriden, Connecticut to obtain vibration and environmental data. Experimental testing results show that the variability of measured natural frequencies due to temperature is captured, and the temperature-induced changes in natural frequencies have been considered prior to the establishment of the threshold in the damage warning system. This novel approach is applicable for structural health monitoring system and helpful to assess the performance of the structure for bridge management and maintenance.

Modelling direction solidification

NASA Technical Reports Server (NTRS)

Wilcox, W. R.

1986-01-01

The overall objective of this program is to develop an improved understanding of some phenomena of importance to directional solidification. The aim of this research is also to help predict differences in behavior between solidification on Earth and solidification in space. In this report, the validity of the Burton-Primslichter equation is explored. The influence of operating variables on grain and twin generation and propagation in single crystals of In sub (x) Ga sub (1-x) Sb is also investigated.

HIGH-SHEAR GRANULATION PROCESS: INFLUENCE OF PROCESSING PARAMETERS ON CRITICAL QUALITY ATTRIBUTES OF ACETAMINOPHEN GRANULES AND TABLETS USING DESIGN OF EXPERIMENT APPROACH.

PubMed

Fayed, Mohamed H; Abdel-Rahman, Sayed I; Alanazi, Fars K; Ahmed, Mahrous O; Tawfeek, Hesham M; Al-Shedfat, Ramadan I

2017-01-01

Application of quality by design (QbD) in high shear granulation process is critical and need to recognize the correlation between the granulation process parameters and the properties of intermediate (granules) and corresponding final product (tablets). The present work examined the influence of water amount (X,) and wet massing time (X2) as independent process variables on the critical quality attributes of granules and corresponding tablets using design of experiment (DoE) technique. A two factor, three level (32) full factorial design was performed; each of these variables was investigated at three levels to characterize their strength and interaction. The dried granules have been analyzed for their size distribution, density and flow pattern. Additionally, the produced tablets have been investigated for weight uniformity, crushing strength, friability and percent capping, disintegration time and drug dissolution. Statistically significant impact (p < 0.05) of water amount was identified for granule growth, percent fines and distribution width and flow behavior. Granule density and compressibility were found to be significantly influenced (p < 0.05) by the two operating conditions. Also, water amount has significant effect (p < 0.05) on tablet weight unifornity, friability and percent capping. Moreover, tablet disintegration time and drug dissolution appears to be significantly influenced (p < 0.05) by the two process variables. On the other hand, the relationship of process parameters with critical quality attributes of granule and final product tablet was identified and correlated. Ultimately, a judicious selection of process parameters in high shear granulation process will allow providing product of desirable quality.

The Spectrum of Wind Power Fluctuations

NASA Astrophysics Data System (ADS)

Bandi, Mahesh

2016-11-01

Wind is a variable energy source whose fluctuations threaten electrical grid stability and complicate dynamical load balancing. The power generated by a wind turbine fluctuates due to the variable wind speed that blows past the turbine. Indeed, the spectrum of wind power fluctuations is widely believed to reflect the Kolmogorov spectrum; both vary with frequency f as f - 5 / 3. This variability decreases when aggregate power fluctuations from geographically distributed wind farms are averaged at the grid via a mechanism known as geographic smoothing. Neither the f - 5 / 3 wind power fluctuation spectrum nor the mechanism of geographic smoothing are understood. In this work, we explain the wind power fluctuation spectrum from the turbine through grid scales. The f - 5 / 3 wind power fluctuation spectrum results from the largest length scales of atmospheric turbulence of order 200 km influencing the small scales where individual turbines operate. This long-range influence spatially couples geographically distributed wind farms and synchronizes farm outputs over a range of frequencies and decreases with increasing inter-farm distance. Consequently, aggregate grid-scale power fluctuations remain correlated, and are smoothed until they reach a limiting f - 7 / 3 spectrum. This work was funded by the Collective Interactions Unit, OIST Graduate University, Japan.

Structural positioning of nurse leaders and empowerment.

PubMed

Hughes, Kerri-Ann; Carryer, Jennifer Barbara; White, Jill

2015-08-01

To analyse the reporting structures of nursing leaders of publicly funded hospitals and seek both the views of nurse leaders and Chief Executive Officers/Chief Operating Officers on the structural positioning of nurse leaders in the organisation. Concern that the continuing restructuring within hospital structures and focus on economic outputs in health services is diminishing the value of nursing leadership. Qualitative surveys with Nursing leaders and Chief Executive Officers of public hospitals. Seventeen Directors of Nursing and 10 Chief Executive Officer/Chief Operating Officers' responses were received using two semi-structured questionnaires. Themes were developed from data coded and analysed by hand. Four broad themes emerged from analysis of the data: (1) variable positional reporting between Director of Nursing and Chief Executive Officers occurred; (2) variable levels of inclusion and influence at the executive decision-making level; (3) ambiguous financial responsibilities and accountabilities held by Director of Nursing; and (4) blurred lines existed between operational and professional reporting lines. Findings unique to the research indicate that the varying levels of visibility and inclusion impact on the structural positioning of nurse leaders which influences authority and empowerment. Responses from the data analysis indicate that the structural power of nurse leaders defined by the factors of opportunity, power and proportion were hindered by dual accountability reporting lines and a lack of financial control. The structural positioning of nurse leaders is vital to ensure that they are empowered and able to meet the adaptations required in a changing environment that supports the delivery of effective, quality healthcare. © 2015 John Wiley & Sons Ltd.

Factors Influencing Complications of Percutaneous Nephrolithotomy: A Single-Center Study.

PubMed

Oner, Sedat; Okumus, Muhammed Masuk; Demirbas, Murat; Onen, Efe; Aydos, Mustafa Murat; Ustun, Mehmet Hakan; Kilic, Metin; Avci, Sinan

2015-11-14

Percutaneous nephrolithotomy (PNL) is a minimally invasive procedure used for successful treatment of renal calculi. However, it is associated with various complications. We assessed the complications and their potential influencing factors in patients who had undergone PNL. In total, 1750 patients who had undergone PNL from November 2003 to June 2011 were evaluated retrospectively. PNL complications and possible contributing risk factors (age, sex, serum creatinine level, previous operations, hydronephrosis, calculi size, localization, opacity, surgeon's experience, accessed calyxes, number of accesses, and costal entries) were determined. Receiver operating characteristic (ROC) analysis was used to investigate the cutoff values of the data. Ideal cutoff value was determined by Youden's J statistic. All the demographic and clinical variables were examined using backward stepwise logistical regression analysis. Continuous variables were categorized with logistic regression analysis according to the cutoff values. Complications occurred in 396 (24.4%) patients who had undergone PNL. Hemorrhage requiring blood transfusion occurred in 221 (12.6%) patients, hemorrhage requiring arterial embolization occurred in 7 (0.4%) patients, perirenal hematoma occurred in 17 (0.97%) patients, hemo-pneumothorax occurred in 32 (1.8%) patients, and colon perforation occurred in 4 (0.22%) patients. Three patients (0.06%) died of severe urosepsis, and one patient (0.02%) died of severe bleeding. The calculus size, localization, access site, number of accesses, presence of staghorn stones, surgeon's experience, and duration of the operation significantly affected the complication risk. Our retrospective evaluation of this large patient series reveals that, PNL is a very effective treatment modality for kidney stones. However, although rare, serious complications including death can occur.

Do radio frequencies of medical instruments common in the operating room interfere with near-infrared spectroscopy signals?

NASA Astrophysics Data System (ADS)

Shadgan, Babak; Molavi, Behnam; Reid, W. D.; Dumont, Guy; Macnab, Andrew J.

2010-02-01

Background: Medical and diagnostic applications of near infrared spectroscopy (NIRS) are increasing, especially in operating rooms (OR). Since NIRS is an optical technique, radio frequency (RF) interference from other instruments is unlikely to affect the raw optical data, however, NIRS data processing and signal output could be affected. Methods: We investigated the potential for three common OR instruments: an electrical cautery, an orthopaedic drill and an imaging system, to generate electromagnetic interference (EMI) that could potentially influence NIRS signals. The time of onset and duration of every operation of each device was recorded during surgery. To remove the effects of slow changing physiological variables, we first used a lowpass filter and then selected 2 windows with variable lengths around the moment of device onset. For each instant, variances (energy) and means of the signals in the 2 windows were compared. Results: Twenty patients were studied during ankle surgery. Analysis shows no statistically significant difference in the means and variance of the NIRS signals (p < 0.01) during operation of any of the three devices for all surgeries. Conclusion: This method confirms the instruments evaluated caused no significant interference. NIRS can potentially be used without EMI in clinical environments such as the OR.

Antecedent influences on behavior disorders.

PubMed Central

Smith, R G; Iwata, B A

1997-01-01

The influence of antecedent events on behavior disorders has been relatively understudied by applied behavior analysts. This lack of research may be due to a focus on consequences as determinants of behavior and a historical disagreement on a conceptual framework for describing and interpreting antecedent variables. We suggest that antecedent influences can be described using terms derived from basic behavioral principles and that their functional properties can be adequately interpreted as discriminative and establishing operations. A set of studies on assessment and treatment of behavior disorders was selected for review based on their relevance to the topic of antecedent events. These studies were categorized as focusing on assessment of antecedent events, antecedent treatments for behavior disorders maintained by either positive or negative reinforcement, and special cases of antecedent events in behavior disorders. Some directions for future research on antecedent influences in the analysis and treatment of behavior disorders are discussed. PMID:9210312

JIGSAW: Preference-directed, co-operative scheduling

NASA Technical Reports Server (NTRS)

Linden, Theodore A.; Gaw, David

1992-01-01

Techniques that enable humans and machines to cooperate in the solution of complex scheduling problems have evolved out of work on the daily allocation and scheduling of Tactical Air Force resources. A generalized, formal model of these applied techniques is being developed. It is called JIGSAW by analogy with the multi-agent, constructive process used when solving jigsaw puzzles. JIGSAW begins from this analogy and extends it by propagating local preferences into global statistics that dynamically influence the value and variable ordering decisions. The statistical projections also apply to abstract resources and time periods--allowing more opportunities to find a successful variable ordering by reserving abstract resources and deferring the choice of a specific resource or time period.

A Review of Primary and Secondary Influences on Sport Expertise

ERIC Educational Resources Information Center

Baker, Joseph; Horton, Sean

2004-01-01

Sport scientists have examined numerous factors influencing the acquisition and manifestation of high levels of performance. These factors can be divided into variables having a primary influence on expertise and variables that have a secondary influence through their interaction with other variables. Primary influences on expertise include…

Predictors of complication for alveolar cleft bone graft.

PubMed

Borba, Alexandre Meireles; Borges, Alvaro Henrique; da Silva, Carolina Silvano Vilarinho; Brozoski, Mariana Aparecida; Naclério-Homem, Maria da Graça; Miloro, Michael

2014-02-01

We have analysed the predictors of postoperative complications and the need for reoperation after grafting of the alveolar cleft from one specialised cleft centre. The data were obtained from hospital casenotes of patients operated on from December 2004 to April 2010, with a minimum one-year follow-up from the final operation. Independent variables included postoperative complications and the need for reoperation. Conditional variables were sex, age, type of cleft, sides affected, donor area, type of graft material, and the presence of an erupted tooth in contact with the cleft. A total of 71 patients had bone grafted on to the alveolar cleft. The following associations were found to be significant: postoperative complications and need for reoperation (p=0.003); age and complications (p=0.002); affected side and complications (p=0.006); age and reoperation (p=0.000); sex and reoperation (p=0.001); and type of cleft and reoperation (p=0.001). Proper attention should be given to all the variables and risk factors to overcome the many obstacles that might have an adverse influence on a successful outcome of alveolar bone grafting for patients with clefts. Copyright © 2013 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Placing Local Aggregations in a Larger-Scale Context: Hierarchical Modeling of Black-Footed Albatross Dispersion.

PubMed

Michael, P E; Jahncke, J; Hyrenbach, K D

2016-01-01

At-sea surveys facilitate the study of the distribution and abundance of marine birds along standardized transects, in relation to changes in the local environmental conditions and large-scale oceanographic forcing. We analyzed the form and the intensity of black-footed albatross (Phoebastria nigripes: BFAL) spatial dispersion off central California, using five years (2004-2008) of vessel-based surveys of seven replicated survey lines. We related BFAL patchiness to local, regional and basin-wide oceanographic variability using two complementary approaches: a hypothesis-based model and an exploratory analysis. The former tested the strength and sign of hypothesized BFAL responses to environmental variability, within a hierarchical atmosphere-ocean context. The latter explored BFAL cross-correlations with atmospheric / oceanographic variables. While albatross dispersion was not significantly explained by the hierarchical model, the exploratory analysis revealed that aggregations were influenced by static (latitude, depth) and dynamic (wind speed, upwelling) environmental variables. Moreover, the largest BFAL patches occurred along the survey lines with the highest densities, and in association with shallow banks. In turn, the highest BFAL densities occurred during periods of negative Pacific Decadal Oscillation index values and low atmospheric pressure. The exploratory analyses suggest that BFAL dispersion is influenced by basin-wide, regional-scale and local environmental variability. Furthermore, the hypothesis-based model highlights that BFAL do not respond to oceanographic variability in a hierarchical fashion. Instead, their distributions shift more strongly in response to large-scale ocean-atmosphere forcing. Thus, interpreting local changes in BFAL abundance and dispersion requires considering diverse environmental forcing operating at multiple scales.

Are gestational age, birth weight, and birth length indicators of favorable fetal growth conditions? A structural equation analysis of Filipino infants.

PubMed

Bollen, Kenneth A; Noble, Mark D; Adair, Linda S

2013-07-30

The fetal origins hypothesis emphasizes the life-long health impacts of prenatal conditions. Birth weight, birth length, and gestational age are indicators of the fetal environment. However, these variables often have missing data and are subject to random and systematic errors caused by delays in measurement, differences in measurement instruments, and human error. With data from the Cebu (Philippines) Longitudinal Health and Nutrition Survey, we use structural equation models, to explore random and systematic errors in these birth outcome measures, to analyze how maternal characteristics relate to birth outcomes, and to take account of missing data. We assess whether birth weight, birth length, and gestational age are influenced by a single latent variable that we call favorable fetal growth conditions (FFGC) and if so, which variable is most closely related to FFGC. We find that a model with FFGC as a latent variable fits as well as a less parsimonious model that has birth weight, birth length, and gestational age as distinct individual variables. We also demonstrate that birth weight is more reliably measured than is gestational age. FFGCs were significantly influenced by taller maternal stature, better nutritional stores indexed by maternal arm fat and muscle area during pregnancy, higher birth order, avoidance of smoking, and maternal age 20-35 years. Effects of maternal characteristics on newborn weight, length, and gestational age were largely indirect, operating through FFGC. Copyright © 2013 John Wiley & Sons, Ltd.

Operational Definitions of Sexual Orientation and Estimates of Adolescent Health Risk Behaviors

PubMed Central

Matthews, Derrick D.; Blosnich, John R.; Farmer, Grant W.; Adams, Brian J.

2014-01-01

Purpose Increasing attention to the health of lesbian, gay, and bisexual (LGB) populations comes with requisite circumspection about measuring sexual orientation in surveys. However, operationalizing these variables also requires considerable thought. This research sought to document the consequences of different operational definitions of sexual orientation by examining variation in health risk behaviors. Methods Using Massachusetts Youth Risk Behavior Survey data, we examined how operational definitions of sexual behavior and sexual identity influenced differences among three health behaviors known to disparately affect LGB populations: smoking, suicide risk, and methamphetamine use. Sexual behavior and sexual identity were also examined together to explore if they captured unique sources of variability in behavior. Results Estimates of health disparities changed as a result of using either sexual behavior or sexual identity. Youth who reported their sexual identity as “not sure” also had increased odds of health risk behavior. Disaggregating bisexual identity and behavior from same-sex identity and behavior frequently resulted in the attenuation or elimination of health disparities that would have otherwise been attributable to exclusively same-sex sexual minorities. Finally, sexual behavior and sexual identity explained unique and significant sources of variability in all three health behaviors. Conclusion Researchers using different operational definitions of sexual orientation could draw different conclusions, even when analyzing the same data, depending upon how they chose to represent sexual orientation in analyses. We discuss implications that these manipulations have on data interpretation and provide specific recommendations for best-practices when analyzing sexual orientation data collected from adolescent populations. PMID:25110718

Nitrification of an industrial wastewater in a moving-bed biofilm reactor: effect of salt concentration.

PubMed

Vendramel, Simone; Dezotti, Marcia; Sant'Anna, Geraldo L

2011-01-01

Nitrification of wastewaters from chemical industries can pose some challenges due to the presence of inhibitory compounds. Some wastewaters, besides their organic complexity present variable levels of salt concentration. In order to investigate the effect of salt (NaCl) content on the nitrification of a conventional biologically treated industrial wastewater, a bench scale moving-bed biofilm reactor was operated on a sequencing batch mode. The wastewater presenting a chloride content of 0.05 g l(-1) was supplemented with NaCl up to 12 g Cl(-) l(-1). The reactor operation cycle was: filling (5 min), aeration (12 or 24h), settling (5 min) and drawing (5 min). Each experimental run was conducted for 3 to 6 months to address problems related to the inherent wastewater variability and process stabilization. A PLC system assured automatic operation and control of the pertinent process variables. Data obtained from selected batch experiments were adjusted by a kinetic model, which considered ammonia, nitrite and nitrate variations. The average performance results indicated that nitrification efficiency was not influenced by chloride content in the range of 0.05 to 6 g Cl(-) l(-1) and remained around 90%. When the chloride content was 12 g Cl(-) l(-1), a significant drop in the nitrification efficiency was observed, even operating with a reaction period of 24 h. Also, a negative effect of the wastewater organic matter content on nitrification efficiency was observed, which was probably caused by growth of heterotrophs in detriment of autotrophs and nitrification inhibition by residual chemicals.

Analysis of non-fatal and fatal injury rates for mine operator and contractor employees and the influence of work location.

PubMed

Karra, Vijia K

2005-01-01

Mining injury surveillance data are used as the basis for assessing the severity of injuries among operator and contractor employees in the underground and surface mining of various minerals. Injury rates during 1983-2002 derived from Mine Safety and Health Administration (MSHA) database are analyzed using the negative binomial regression model. The logarithmic mean injury rate is expressed as a linear function of seven indicator variables representing Non-Coal Contractor, Metal Operator, Non Metal Operator, Stone Operator, Sand and Gravel Operator, Coal Contractor, and Work Location, and a continuous variable, RelYear, representing the relative year starting with 1983 as the base year. Based on the model, the mean injury rate declined at a 1.69% annual rate, and the mean injury rate for work on the surface is 52.53% lower compared to the rate for work in the underground. With reference to the Coal Operator mean injury rate: the Non-Coal Contractor rate is 30.34% lower, the Metal Operator rate is 27.18% lower, the Non-Metal Operator rate is 37.51% lower, the Stone Operator rate is 23.44% lower, the Sand and Gravel Operator rate is 16.45% lower, and the Coal Contractor rate is 1.41% lower. Fatality rates during the same 20 year period are analyzed similarly using Poisson regression model. Based on this model, the mean fatality rate declined at a 3.17% annual rate, and the rate for work on the surface is 64.3% lower compared to the rate for work in the underground. With reference to the Coal Operator mean fatality rate: the Non-Coal Contractor rate is 234.81% higher, the Metal Operator rate is 5.79% lower, the Non-Metal Operator rate is 47.36% lower, the Stone Operator rate is 8.29% higher, the Sand and Gravel Operator rate is 60.32% higher, and the Coal Contractor rate is 129.54% higher.

Determinants explaining the variability of hand-transmitted vibration emissions from two different work tasks: grinding and cutting using angle grinders.

PubMed

Liljelind, Ingrid; Pettersson, Hans; Nilsson, Leif; Wahlström, Jens; Toomingas, Allan; Lundström, Ronnie; Burström, Lage

2013-10-01

There are numerous factors including physical, biomechanical, and individual that influence exposure to hand-transmitted vibration (HTV) and cause variability in the exposure measurements. Knowledge of exposure variability and determinants of exposure could be used to improve working conditions. We performed a quasi-experimental study, where operators performed routine work tasks in order to obtain estimates of the variance components and to evaluate the effect of determinants, such as machine-wheel combinations and individual operator characteristics. Two pre-defined simulated work tasks were performed by 11 operators: removal of a weld puddle of mild steel and cutting of a square steel pipe. In both tasks, four angle grinders were used, two running on compressed air and two electrically driven. Two brands of both grinding and cutting wheels were used. Each operator performed both tasks twice in a random order with each grinder and wheel and the time to complete each task was recorded. Vibration emission values were collected and the wheel wear was measured as loss of weight. Operators' characteristics collected were as follows: age, body height and weight, length and volume of their hands, maximum hand grip force, and length of work experience with grinding machines (years). The tasks were also performed by one operator who used four machines of the same brand. Mixed and random effects models were used in the statistical evaluation. The statistical evaluation was performed for grinding and cutting separately and we used a measure referring to the sum of the 1-s r.m.s. average frequency-weighted acceleration over time for completing the work task (a(sa)). Within each work task, there was a significant effect as a result of the determinants 'the machine used', 'wheel wear', and 'time taken to complete the task'. For cutting, 'the brand of wheel' used also had a significant effect. More than 90% of the inherent variability in the data was explained by the determinants. The two electrically powered machines had a mean a(sa) that was 2.6 times higher than the two air-driven machines. For cutting, the effect of the brand of wheel on a(sa) was ~0.1 times. The a(sa) increased both with increasing wheel wear and with time taken to complete the work task. However, there were also a number of interaction effects which, to a minor extent, modified the a(sa). Only a minor part (1%) of the total variability was attributed to the operator: for cutting, the volume of the hands, maximum grip force, and body weight were significant, while for grinding, it was the maximum grip force. There was no clear difference in a(sa) between the four copies of the same brand of each machine. By including determinants that were attributed to the brand of both machine and wheel used as well as the time taken to complete the work task, we were able to explain >90% of the variability. The dominating determinant was the brand of the machine. Little variability was found between operators, indicating that the overall effect as due to the operator was small.

A waste characterisation procedure for ADM1 implementation based on degradation kinetics.

PubMed

Girault, R; Bridoux, G; Nauleau, F; Poullain, C; Buffet, J; Steyer, J-P; Sadowski, A G; Béline, F

2012-09-01

In this study, a procedure accounting for degradation kinetics was developed to split the total COD of a substrate into each input state variable required for Anaerobic Digestion Model n°1. The procedure is based on the combination of batch experimental degradation tests ("anaerobic respirometry") and numerical interpretation of the results obtained (optimisation of the ADM1 input state variable set). The effects of the main operating parameters, such as the substrate to inoculum ratio in batch experiments and the origin of the inoculum, were investigated. Combined with biochemical fractionation of the total COD of substrates, this method enabled determination of an ADM1-consistent input state variable set for each substrate with affordable identifiability. The substrate to inoculum ratio in the batch experiments and the origin of the inoculum influenced input state variables. However, based on results modelled for a CSTR fed with the substrate concerned, these effects were not significant. Indeed, if the optimal ranges of these operational parameters are respected, uncertainty in COD fractionation is mainly limited to temporal variability of the properties of the substrates. As the method is based on kinetics and is easy to implement for a wide range of substrates, it is a very promising way to numerically predict the effect of design parameters on the efficiency of an anaerobic CSTR. This method thus promotes the use of modelling for the design and optimisation of anaerobic processes. Copyright © 2012 Elsevier Ltd. All rights reserved.

Report on Survey Implementation. Research Triangle Institute, Caliber Associates and Human Resources Research Organization

DTIC Science & Technology

1994-03-01

DISTRIBUTION /AVAILABILITY STATEMENT 12b. DISTRIBUTION CODE Approved for public release; distribution is unlimited. 13. ABSTRACT ( Maximum 200 words) This...different factors influence degree of readiness. The Army currently does not have an operational set of reliable, comprehensive, and valid measures of...the p.ro . . ....iky th .. ... - ou... ,,,,,,,uni.,.,ucceaa I&Ar COm.FI.,,, AIO W.Wa .’,U.J M-SS-oU, (b) the variable would be a valid indicator of

Applying an intelligent model and sensitivity analysis to inspect mass transfer kinetics, shrinkage and crust color changes of deep-fat fried ostrich meat cubes.

PubMed

Amiryousefi, Mohammad Reza; Mohebbi, Mohebbat; Khodaiyan, Faramarz

2014-01-01

The objectives of this study were to use image analysis and artificial neural network (ANN) to predict mass transfer kinetics as well as color changes and shrinkage of deep-fat fried ostrich meat cubes. Two generalized feedforward networks were separately developed by using the operation conditions as inputs. Results based on the highest numerical quantities of the correlation coefficients between the experimental versus predicted values, showed proper fitting. Sensitivity analysis results of selected ANNs showed that among the input variables, frying temperature was the most sensitive to moisture content (MC) and fat content (FC) compared to other variables. Sensitivity analysis results of selected ANNs showed that MC and FC were the most sensitive to frying temperature compared to other input variables. Similarly, for the second ANN architecture, microwave power density was the most impressive variable having the maximum influence on both shrinkage percentage and color changes. Copyright © 2013 Elsevier Ltd. All rights reserved.

Hybrid performance measurement of a business process outsourcing - A Malaysian company perspective

NASA Astrophysics Data System (ADS)

Oluyinka, Oludapo Samson; Tamyez, Puteri Fadzline; Kie, Cheng Jack; Freida, Ayodele Ozavize

2017-05-01

It's no longer new that customer perceived value for product and services are now greatly influenced by its psychological and social advantages. In order to meet up with the increasing operational cost, response time, quality and innovative capabilities many companies turned their fixed operational cost to a variable cost through outsourcing. Hence, the researcher explored different underlying outsourcing theories and infer that these theories are essential to performance improvement. In this study, the researcher evaluates the performance of a business process outsource company by a combination of lean and agile method. To test the hypotheses, we analyze different variability that a business process company faces, how lean and agile have been used in other industry to address such variability and discuss the result using a predictive multiple regression analysis on data collected from companies in Malaysia. The findings from this study revealed that while each method has its own advantage, a business process outsource company could achieve more (up to 87%) increase in performance level by developing a strategy which focuses on a perfect mixture of lean and agile improvement methods. Secondly, this study shows that performance indicator could be better evaluated with non-metrics variables of the agile method. Thirdly, this study also shows that business process outsourcing company could perform better when they concentrate more on strengthening internal process integration of employees.

[Type 2 Diabetes Mellitus, Depression and Eating Disorders in Patients Submitted to Bariatric Surgery].

PubMed

Brandão, Isabel; Marques Pinho, Ana; Arrojado, Filipa; Pinto-Bastos, Ana; Maia da Costa, José; Coelho, Rui; Calhau, Conceição; Conceição, Eva

2016-03-01

Obesity is associated with a great number of complications, including type 2 diabetes mellitus and psychiatric pathology. Bariatric surgery is the best solution to weight loss and improvement of complications in morbid obese patients. This study aims to analyze the evolution of type 2 diabetes mellitus and psychopathologic variables before and after bariatric surgery and assess the importance of different variables in weight loss. This is a longitudinal study, which evaluates 75 patients before and after bariatric surgery (47 - LAGB - laparoscopic adjustable gastric band; 19 - RYGB - Roux-en-Y gastric bypass; 9 - sleeve) with a follow-up time between 18 and 46 months. A clinical interview and self report questionnaires were applied - Eating Disorder Examination questionnaire - EDE-Q and Beck Depression Inventory - BDI. Results show an improvement in type 2 diabetes mellitus after surgery (X2 (1) = 26.132, p < 0.001). There was not a significant improvement among psychiatric pathology when we controlled the analysis for the type of surgery. It was verified that type 2 diabetes mellitus, depression and eating disorders in post-operative period are associated with less weight loss. This model explains 27% of weight variance after surgery (R2 = 0.265) and it is significant F (3.33) = 2.981, p = 0.038. Type 2 diabetes mellitus, psychiatric pathology and eating disorders after surgery influenced weight loss. It was not clear in what way this relation was verified, neither the relation that these metabolic and psychological variables may have during the postoperative period. Type 2 diabetes mellitus improved after surgery. Type 2 diabetes mellitus, depression and eating disorders influenced weight loss in the postoperative period. These variables did not influence weight loss in the preoperative period.

Optimization study for high speed radial turbine with special reference to design variables

NASA Technical Reports Server (NTRS)

Khalil, I.; Tabakoff, W.

1977-01-01

Numerical results of a theoretical investigation are presented to provide information about the effect of variation of the different design and operating parameters on radial inflow turbine performance. The effects of variations in the mass flow rate, rotor tip Mach number, inlet flow angles, number of rotor blades and hub to shroud radius ratio, on the internal fluid dynamics of turbine rotors, was investigated. A procedure to estimate the flow deviation angles at the turbine exit is also presented and used to examine the influence of the operating conditions and the rotor geometrical configuration on these deviations. The significance of the results obtained is discussed with respect to improved turbine performance.

Multivariate Analysis of Solar Spectral Irradiance Measurements

NASA Technical Reports Server (NTRS)

Pilewskie, P.; Rabbette, M.

2001-01-01

Principal component analysis is used to characterize approximately 7000 downwelling solar irradiance spectra retrieved at the Southern Great Plains site during an Atmospheric Radiation Measurement (ARM) shortwave intensive operating period. This analysis technique has proven to be very effective in reducing a large set of variables into a much smaller set of independent variables while retaining the information content. It is used to determine the minimum number of parameters necessary to characterize atmospheric spectral irradiance or the dimensionality of atmospheric variability. It was found that well over 99% of the spectral information was contained in the first six mutually orthogonal linear combinations of the observed variables (flux at various wavelengths). Rotation of the principal components was effective in separating various components by their independent physical influences. The majority of the variability in the downwelling solar irradiance (380-1000 nm) was explained by the following fundamental atmospheric parameters (in order of their importance): cloud scattering, water vapor absorption, molecular scattering, and ozone absorption. In contrast to what has been proposed as a resolution to a clear-sky absorption anomaly, no unexpected gaseous absorption signature was found in any of the significant components.

Passive landfill gas emission - Influence of atmospheric pressure and implications for the operation of methane-oxidising biofilters.

PubMed

Gebert, Julia; Groengroeft, Alexander

2006-01-01

A passively vented landfill site in Northern Germany was monitored for gas emission dynamics through high resolution measurements of landfill gas pressure, flow rate and composition as well as atmospheric pressure and temperature. Landfill gas emission could be directly related to atmospheric pressure changes on all scales as induced by the autooscillation of air, diurnal variations and the passage of pressure highs and lows. Gas flux reversed every 20 h on average, with 50% of emission phases lasting only 10h or less. During gas emission phases, methane loads fed to a connected methane oxidising biofiltration unit varied between near zero and 247 g CH4 h(-1)m(-3) filter material. Emission dynamics not only influenced the amount of methane fed to the biofilter but also the establishment of gas composition profiles within the biofilter, thus being of high relevance for biofilter operation. The duration of the gas emission phase emerged as most significant variable for the distribution of landfill gas components within the biofilter.

Draft Tube Baffle (DTB) crystallizers: A study of stationary and dynamically behaving Crystal Size Distributions (CSD)

NASA Astrophysics Data System (ADS)

Deleer, B. G. M.

1981-11-01

Based on population balance, CSD behavior as a function of geometrical and operating variables was studied, using a crystallizer. A potash alum-water system, involving a separation technique which uses surface active agents and an apolar, organic liquid to separate potash alum crystals from mother liquid under the influence of gravity was used to check experimental findings against literature data. Results show action of annular settling spaces is strongly influenced by fluid velocities perpendicular to those directed upwards. The well-mixed volume decreases with increasing crystallizer size until a minimum effective volume is reached. As supersaturation is constant throughout the crystallizer volume under stationary operating conditions, the annular settling space behaves like a growth chamber for crystals in its volume. Swirl in the lower part of the annular volume introduces significant back mixing. Crystals within this space either grow and return to the well-mixed part, or withdraw from the annular volume permanently.

Using Seasonal Forecasts for medium-term Electricity Demand Forecasting on Italy

NASA Astrophysics Data System (ADS)

De Felice, M.; Alessandri, A.; Ruti, P.

2012-12-01

Electricity demand forecast is an essential tool for energy management and operation scheduling for electric utilities. In power engineering, medium-term forecasting is defined as the prediction up to 12 months ahead, and commonly is performed considering weather climatology and not actual forecasts. This work aims to analyze the predictability of electricity demand on seasonal time scale, considering seasonal samples, i.e. average on three months. Electricity demand data has been provided by Italian Transmission System Operator for eight different geographical areas, in Fig. 1 for each area is shown the average yearly demand anomaly for each season. This work uses data for each summer during 1990-2010 and all the datasets have been pre-processed to remove trends and reduce the influence of calendar and economic effects. The choice of focusing this research on the summer period is due to the critical peaks of demand that power grid is subject during hot days. Weather data have been included considering observations provided by ECMWF ERA-INTERIM reanalyses. Primitive variables (2-metres temperature, pressure, etc) and derived variables (cooling and heating degree days) have been averaged for summer months. A particular attention has been given to the influence of persistence of positive temperature anomaly and a derived variable which count the number of consecutive days of extreme-days has been used. Electricity demand forecast has been performed using linear and nonlinear regression methods and stepwise model selection procedures have been used to perform a variable selection with respect to performance measures. Significance tests on multiple linear regression showed the importance of cooling degree days during summer in the North-East and South of Italy with an increase of statistical significance after 2003, a result consistent with the diffusion of air condition and ventilation equipment in the last decade. Finally, using seasonal climate forecasts we evaluate the performances of electricity demand forecast performed with predicted variables on Italian regions with encouraging results on the South of Italy. This work gives an initial assessment on the predictability of electricity demand on seasonal time scale, evaluating the relevance of climate information provided by seasonal forecasts for electricity management during high-demand periods.;

Organizational variables on nurses' job performance in Turkey: nursing assessments.

PubMed

Top, Mehmet

2013-01-01

The purpose of this study was to describe the influence of organizational variables on hospital staff nurses' job performance as reported by staff nurses in two cities in Turkey. Hospital ownership status, employment status were examined for their effect on this influence. The reported influence of organizational variables on job performance was measured by a questionnaire developed for this study. Nurses were asked to evaluate the influence of 28 organizational variables on their job performance using a five-point Likert-type scale (1- Never effective, 5- Very effective). The study used comparative and descriptive study design. The staff nurses who were included in this study were 831 hospital staff nurses. Descriptive statistics, frequencies, t-test, ANOVA and factor analysis were used for data analysis. The study showed the relative importance of the 28 organizational variables in influencing nurses' job performance. Nurses in this study reported that workload and technological support are the most influential organizational variables on their job performance. Factor analysis yielded a five-factor model that explained 53.99% of total variance. Administratively controllable influence job organizational variables influence job performance of nurses in different magnitude.

Assessing the Influence of Vegan, Vegetarian and Omnivore Oriented Westernized Dietary Styles on Human Gut Microbiota: A Cross Sectional Study.

PubMed

Losasso, Carmen; Eckert, Ester M; Mastrorilli, Eleonora; Villiger, Jorg; Mancin, Marzia; Patuzzi, Ilaria; Di Cesare, Andrea; Cibin, Veronica; Barrucci, Federica; Pernthaler, Jakob; Corno, Gianluca; Ricci, Antonia

2018-01-01

Diet and lifestyle have a strong influence on gut microbiota, which in turn has important implications on a variety of health-related aspects. Despite great advances in the field, it remains unclear to which extent the composition of the gut microbiota is modulated by the intake of animal derived products, compared to a vegetable based diet. Here the specific impact of vegan, vegetarian, and omnivore feeding type on the composition of gut microbiota of 101 adults was investigated among groups homogeneous for variables known to have a role in modulating gut microbial composition such as age, anthropometric variables, ethnicity, and geographic area. The results displayed a picture where the three different dietetic profiles could be well distinguished on the basis of participant's dietetic regimen. Regarding the gut microbiota; vegetarians had a significantly greater richness compared to omnivorous. Moreover, counts of Bacteroidetes related operational taxonomic units (OTUs) were greater in vegans and vegetarians compared to omnivores. Interestingly considering the whole bacterial community composition the three cohorts were unexpectedly similar, which is probably due to their common intake in terms of nutrients rather than food, e.g., high fat content and reduced protein and carbohydrate intake. This finding suggests that fundamental nutritional choices such as vegan, vegetarian, or omnivore do influence the microbiota but do not allow to infer conclusions on gut microbial composition, and suggested the possibility for a preferential impact of other variables, probably related to the general life style on shaping human gut microbial community in spite of dietary influence. Consequently, research were individuals are categorized on the basis of their claimed feeding types is of limited use for scientific studies, since it appears to be oversimplified.

Assessing the Influence of Vegan, Vegetarian and Omnivore Oriented Westernized Dietary Styles on Human Gut Microbiota: A Cross Sectional Study

PubMed Central

Losasso, Carmen; Eckert, Ester M.; Mastrorilli, Eleonora; Villiger, Jorg; Mancin, Marzia; Patuzzi, Ilaria; Di Cesare, Andrea; Cibin, Veronica; Barrucci, Federica; Pernthaler, Jakob; Corno, Gianluca; Ricci, Antonia

2018-01-01

Diet and lifestyle have a strong influence on gut microbiota, which in turn has important implications on a variety of health-related aspects. Despite great advances in the field, it remains unclear to which extent the composition of the gut microbiota is modulated by the intake of animal derived products, compared to a vegetable based diet. Here the specific impact of vegan, vegetarian, and omnivore feeding type on the composition of gut microbiota of 101 adults was investigated among groups homogeneous for variables known to have a role in modulating gut microbial composition such as age, anthropometric variables, ethnicity, and geographic area. The results displayed a picture where the three different dietetic profiles could be well distinguished on the basis of participant’s dietetic regimen. Regarding the gut microbiota; vegetarians had a significantly greater richness compared to omnivorous. Moreover, counts of Bacteroidetes related operational taxonomic units (OTUs) were greater in vegans and vegetarians compared to omnivores. Interestingly considering the whole bacterial community composition the three cohorts were unexpectedly similar, which is probably due to their common intake in terms of nutrients rather than food, e.g., high fat content and reduced protein and carbohydrate intake. This finding suggests that fundamental nutritional choices such as vegan, vegetarian, or omnivore do influence the microbiota but do not allow to infer conclusions on gut microbial composition, and suggested the possibility for a preferential impact of other variables, probably related to the general life style on shaping human gut microbial community in spite of dietary influence. Consequently, research were individuals are categorized on the basis of their claimed feeding types is of limited use for scientific studies, since it appears to be oversimplified. PMID:29556222

Method of operating a thermoelectric generator

DOEpatents

Reynolds, Michael G; Cowgill, Joshua D

2013-11-05

A method for operating a thermoelectric generator supplying a variable-load component includes commanding the variable-load component to operate at a first output and determining a first load current and a first load voltage to the variable-load component while operating at the commanded first output. The method also includes commanding the variable-load component to operate at a second output and determining a second load current and a second load voltage to the variable-load component while operating at the commanded second output. The method includes calculating a maximum power output of the thermoelectric generator from the determined first load current and voltage and the determined second load current and voltage, and commanding the variable-load component to operate at a third output. The commanded third output is configured to draw the calculated maximum power output from the thermoelectric generator.

Influence of El Niño Southern Oscillation on global hydropower production

NASA Astrophysics Data System (ADS)

Ng, Jia Yi; Turner, Sean; Galelli, Stefano

2016-04-01

Hydropower contributes significantly to meeting the world's energy demand, accounting for at least 16% of total electrical output. Its role as a mature and cost competitive renewable energy source is expected to become increasingly important as the world transits to a low-carbon economy. A key component of hydropower production is runoff, which is highly dependent on precipitation and other climate variables. As such, it becomes critical to understand how the drivers of climate variability impact hydropower production. One globally-important driver is the El Niño Southern Oscillation (ENSO). While it is known that ENSO influences hydrological processes, the potential value of its associated teleconnection in design related tasks has yet to be explored at the global scale. Our work seeks to characterize the impact of ENSO on global hydropower production so as to quantify the potential for increased production brought about by incorporating climate information within reservoir operating models. We study over 1,500 hydropower reservoirs - representing more than half the world's hydropower capacity. A historical monthly reservoir inflow time series is assigned to each reservoir from a 0.5 degree gridded global runoff dataset. Reservoir operating rules are designed using stochastic dynamic programming, and storage dynamics are simulated to assess performance under the climate conditions of the 20th century. Results show that hydropower reservoirs in the United States, Brazil, Argentina, Australia, and Eastern China are strongly influenced by ENSO episodes. Statistically significant lag correlations between ENSO indicators and hydropower production demonstrate predictive skill with lead times up to several months. Our work highlights the potential for using these indicators to increase the contribution of existing hydropower plants to global energy supplies.

Strengths and Limitations of Operational Use of 1 Km EO Biophysical Products for Regional Prediction of Grain Yelds in Europe (wheat, barley and maize)

NASA Astrophysics Data System (ADS)

Meroni, M.; LEO, O.; Lopez-Lozano, R.; Baruth, B.; Duveiller, G.; Garcia-Condado, S.; Hooker, J.; Seguini, L.

2014-12-01

The site-specific relationship between EO indicators and actual crop yields has been explored in many different studies, describing semi-empirical regression models between spatially aggregated biophysical parameters or vegetation indices and observed yields (from field measurements or official statistics). However, when considering larger extensions -from countries to continents- agro-climatic conditions and crop management may differ substantially among regions, and these differences may greatly influence the relationship between biophysical indicators and the observed yields, which may be also driven by limiting factors other than green biomass formation. The present study aims to better assess the contribution of EO indicators within an operational crop yield forecasting system in Europe and neighbouring countries, by evaluating how these above mentioned geographic differences influence the relationship between biophysical indicators and crop yield. We therefore explore, as a first step, the correspondence between fAPAR time-series (1999-2013) and the inter-annual yield variability of wheat, barley and grain maize, at sub-national level across Europe (270-450 Administrative Units, depending on crop). In a second step, we map the agro-climatic contexts in which EO indicators better explain the observed yield inter-annual variability, identify the influence of some meteorological events on the fAPAR -yield relationship and provide some recommendations for further investigation. The results indicate that in water-limited environments (e.g. Mediterranean and Black Sea areas), fAPAR is highly correlated with yields whereas in northern Europe, crop yield appears much less limited by leaf area expansion along the season, and the relationship between yield and EO products becomes more difficult to interpret.

Study of relationship between clinical factors and velopharyngeal closure in cleft palate patients

PubMed Central

Chen, Qi; Zheng, Qian; Shi, Bing; Yin, Heng; Meng, Tian; Zheng, Guang-ning

2011-01-01

BACKGROUND: This study was carried out to analyze the relationship between clinical factors and velopharyngeal closure (VPC) in cleft palate patients. METHODS: Chi-square test was used to compare the postoperative velopharyngeal closure rate. Logistic regression model was used to analyze independent variables associated with velopharyngeal closure. RESULTS: Difference of postoperative VPC rate in different cleft types, operative ages and surgical techniques was significant (P=0.000). Results of logistic regression analysis suggested that when operative age was beyond deciduous dentition stage, or cleft palate type was complete, or just had undergone a simple palatoplasty without levator veli palatini retropositioning, patients would suffer a higher velopharyngeal insufficiency rate after primary palatal repair. CONCLUSIONS: Cleft type, operative age and surgical technique were the contributing factors influencing VPC rate after primary palatal repair of cleft palate patients. PMID:22279464

Evaluating Stimulus-Stimulus Pairing and Direct Reinforcement in the Establishment of an Echoic Repertoire of Children Diagnosed with Autism

PubMed Central

Esch, Barbara E; Carr, James E; Michael, Jack

2005-01-01

Many children with autism do not imitate adult vocalizations, an important skill in learning to talk. Pairing adult vocalizations with preferred stimuli has been shown to increase free-operant vocalizations but effects are temporary; thus, direct reinforcement may be necessary to establish durable vocal behaviors. In Experiment 1, directly reinforced echoic responses did not increase following stimulus-stimulus pairings in three children with autism. Similarly, pairings did not increase free-operant vocalizations in Experiment 2, a replication of Miguel et al. (2002). Experiment 3 demonstrated that shaping increased vowel frequency for one participant. Results suggest that variables are yet to be delineated that influence effectiveness of a stimulus-stimulus pairing procedure on vocalization frequency and acquisition of a verbal operant following such pairings. PMID:22477313

A graph model for preventing railway accidents based on the maximal information coefficient

NASA Astrophysics Data System (ADS)

Shao, Fubo; Li, Keping

2017-01-01

A number of factors influences railway safety. It is an important work to identify important influencing factors and to build the relationship between railway accident and its influencing factors. The maximal information coefficient (MIC) is a good measure of dependence for two-variable relationships which can capture a wide range of associations. Employing MIC, a graph model is proposed for preventing railway accidents which avoids complex mathematical computation. In the graph, nodes denote influencing factors of railway accidents and edges represent dependence of the two linked factors. With the increasing of dependence level, the graph changes from a globally coupled graph to isolated points. Moreover, the important influencing factors are identified from many factors which are the monitor key. Then the relationship between railway accident and important influencing factors is obtained by employing the artificial neural networks. With the relationship, a warning mechanism is built by giving the dangerous zone. If the related factors fall into the dangerous zone in railway operations, the warning level should be raised. The built warning mechanism can prevent railway accidents and can promote railway safety.

Factors influencing teamwork and collaboration within a tertiary medical center

PubMed Central

Chien, Shu Feng; Wan, Thomas TH; Chen, Yu-Chih

2012-01-01

AIM: To understand how work climate and related factors influence teamwork and collaboration in a large medical center. METHODS: A survey of 3462 employees was conducted to generate responses to Sexton’s Safety Attitudes Questionnaire (SAQ) to assess perceptions of work environment via a series of five-point, Likert-scaled questions. Path analysis was performed, using teamwork (TW) and collaboration (CO) as endogenous variables. The exogenous variables are effective communication (EC), safety culture (SC), job satisfaction (JS), work pressure (PR), and work climate (WC). The measurement instruments for the variables or summated subscales are presented. Reliability of each sub-scale are calculated. Alpha Cronbach coefficients are relatively strong: TW (0.81), CO (0.76), EC (0.70), SC (0.83), JS (0.91), WP (0.85), and WC (0.78). Confirmatory factor analysis was performed for each of these constructs. RESULTS: Path analysis enables to identify statistically significant predictors of two endogenous variables, teamwork and intra-organizational collaboration. Significant amounts of variance in perceived teamwork (R2 = 0.59) and in collaboration (R2 = 0.75) are accounted for by the predictor variables. In the initial model, safety culture is the most important predictor of perceived teamwork, with a β weight of 0.51, and work climate is the most significant predictor of collaboration, with a β weight of 0.84. After eliminating statistically insignificant causal paths and allowing correlated predictors1, the revised model shows that work climate is the only predictor positively influencing both teamwork (β = 0.26) and collaboration (β = 0.88). A relatively weak positive (β = 0.14) but statistically significant relationship exists between teamwork and collaboration when the effects of other predictors are simultaneously controlled. CONCLUSION: Hospital executives who are interested in improving collaboration should assess the work climate to ensure that employees are operating in a setting conducive to intra-organizational collaboration. PMID:25237612

A one dimensional moving bed biofilm reactor model for nitrification of municipal wastewaters.

PubMed

Barry, Ugo; Choubert, Jean-Marc; Canler, Jean-Pierre; Pétrimaux, Olivier; Héduit, Alain; Lessard, Paul

2017-08-01

This work presents a one-dimensional model of a moving bed bioreactor (MBBR) process designed for the removal of nitrogen from raw wastewaters. A comprehensive experimental strategy was deployed at a semi-industrial pilot-scale plant fed with a municipal wastewater operated at 10-12 °C, and surface loading rates of 1-2 g filtered COD/m 2 d and 0.4-0.55 g NH 4 -N/m 2 d. Data were collected on influent/effluent composition, and on measurement of key variables or parameters (biofilm mass and maximal thickness, thickness of the limit liquid layer, maximal nitrification rate, oxygen mass transfer coefficient). Based on time-course variations in these variables, the MBBR model was calibrated at two time-scales and magnitudes of dynamic conditions, i.e., short-term (4 days) calibration under dynamic conditions and long-term (33 days) calibration, and for three types of carriers. A set of parameters suitable for the conditions was proposed, and the calibrated parameter set is able to simulate the time-course change of nitrogen forms in the effluent of the MBBR tanks, under the tested operated conditions. Parameters linked to diffusion had a strong influence on how robustly the model is able to accurately reproduce time-course changes in effluent quality. Then the model was used to optimize the operations of MBBR layout. It was shown that the main optimization track consists of the limitation of the aeration supply without changing the overall performance of the process. Further work would investigate the influence of the hydrodynamic conditions onto the thickness of the limit liquid layer and the "apparent" diffusion coefficient in the biofilm parameters.

Assessing Command and Control System Vulnerabilities in Underdeveloped, Degraded and Denied Operational Environments

DTIC Science & Technology

2013-06-01

simulation of complex systems (Sterman 2000, Meadows 2008): a) Causal Loop Diagrams. A Causal Loop Diagram ( CLD ) is used to represent the feedback...structure of the dynamic system. CLDs consist of variables in the system being connected by arrows to show their causal influences and relationships. It is...distribution of orders will be included in the model. 6.4.2 Causal Loop Diagrams The CLD , as seen in Figure 5, is derived from the WDA constructs for the

Micro-pulse, differential absorption lidar (dial) network for measuring the spatial and temporal distribution of water vapor in the lower atmosphere

NASA Astrophysics Data System (ADS)

Spuler, Scott; Repasky, Kevin; Hayman, Matt; Nehrir, Amin

2018-04-01

The National Center for Atmospheric Research (NCAR) and Montana State Univeristy (MSU) are developing a test network of five micro-pulse differential absorption lidars to continuously measure high-vertical-resolution water vapor in the lower atmosphere. The instruments are accurate, yet low-cost; operate unattended, and eye-safe - all key features to enable the larger network needed to characterize atmospheric moisture variability which influences important processes related to weather and climate.

Using near infrared spectroscopy and heart rate variability to detect mental overload.

PubMed

Durantin, G; Gagnon, J-F; Tremblay, S; Dehais, F

2014-02-01

Mental workload is a key factor influencing the occurrence of human error, especially during piloting and remotely operated vehicle (ROV) operations, where safety depends on the ability of pilots to act appropriately. In particular, excessively high or low mental workload can lead operators to neglect critical information. The objective of the present study is to investigate the potential of functional near infrared spectroscopy (fNIRS) - a non-invasive method of measuring prefrontal cortex activity - in combination with measurements of heart rate variability (HRV), to predict mental workload during a simulated piloting task, with particular regard to task engagement and disengagement. Twelve volunteers performed a computer-based piloting task in which they were asked to follow a dynamic target with their aircraft, a task designed to replicate key cognitive demands associated with real life ROV operating tasks. In order to cover a wide range of mental workload levels, task difficulty was manipulated in terms of processing load and difficulty of control - two critical sources of workload associated with piloting and remotely operating a vehicle. Results show that both fNIRS and HRV are sensitive to different levels of mental workload; notably, lower prefrontal activation as well as a lower LF/HF ratio at the highest level of difficulty, suggest that these measures are suitable for mental overload detection. Moreover, these latter measurements point toward the existence of a quadratic model of mental workload. Copyright © 2013 Elsevier B.V. All rights reserved.

Hierarchy in factors affecting fish biodiversity in floodplain lakes of the Mississippi Alluvial Valley

USGS Publications Warehouse

Dembkowski, D.J.; Miranda, L.E.

2012-01-01

River-floodplain ecosystems offer some of the most diverse and dynamic environments in the world. Accordingly, floodplain habitats harbor diverse fish assemblages. Fish biodiversity in floodplain lakes may be influenced by multiple variables operating on disparate scales, and these variables may exhibit a hierarchical organization depending on whether one variable governs another. In this study, we examined the interaction between primary variables descriptive of floodplain lake large-scale features, suites of secondary variables descriptive of water quality and primary productivity, and a set of tertiary variables descriptive of fish biodiversity across a range of floodplain lakes in the Mississippi Alluvial Valley of Mississippi and Arkansas (USA). Lakes varied considerably in their representation of primary, secondary, and tertiary variables. Multivariate direct gradient analyses indicated that lake maximum depth and the percentage of agricultural land surrounding a lake were the most important factors controlling variation in suites of secondary and tertiary variables, followed to a lesser extent by lake surface area. Fish biodiversity was generally greatest in large, deep lakes with lower proportions of watershed agricultural land. Our results may help foster a holistic approach to floodplain lake management and suggest the framework for a feedback model wherein primary variables can be manipulated for conservation and restoration purposes and secondary and tertiary variables can be used to monitor the success of such efforts. ?? 2011 Springer Science+Business Media B.V.

Factors affecting fish biodiversity in floodplain lakes of the Mississippi Alluvial Valley

USGS Publications Warehouse

Miranda, Leandro E.; Dembkowski, Daniel J.

2012-01-01

River-floodplain ecosystems offer some of the most diverse and dynamic environments in the world. Accordingly, floodplain habitats harbor diverse fish assemblages. Fish biodiversity in floodplain lakes may be influenced by multiple variables operating on disparate scales, and these variables may exhibit a hierarchical organization depending on whether one variable governs another. In this study, we examined the interaction between primary variables descriptive of floodplain lake large-scale features, suites of secondary variables descriptive of water quality and primary productivity, and a set of tertiary variables descriptive of fish biodiversity across a range of floodplain lakes in the Mississippi Alluvial Valley of Mississippi and Arkansas (USA). Lakes varied considerably in their representation of primary, secondary, and tertiary variables. Multivariate direct gradient analyses indicated that lake maximum depth and the percentage of agricultural land surrounding a lake were the most important factors controlling variation in suites of secondary and tertiary variables, followed to a lesser extent by lake surface area. Fish biodiversity was generally greatest in large, deep lakes with lower proportions of watershed agricultural land. Our results may help foster a holistic approach to floodplain lake management and suggest the framework for a feedback model wherein primary variables can be manipulated for conservation and restoration purposes and secondary and tertiary variables can be used to monitor the success of such efforts.

Operant Variability: Procedures and Processes

ERIC Educational Resources Information Center

Machado, Armando; Tonneau, Francois

2012-01-01

Barba's (2012) article deftly weaves three main themes in one argument about operant variability. From general theoretical considerations on operant behavior (Catania, 1973), Barba derives methodological guidelines about response differentiation and applies them to the study of operant variability. In the process, he uncovers unnoticed features of…

Does integrity of the lesser trochanter influence the surgical outcome of intertrochanteric fracture in elderly patients?

PubMed

Liu, Xiaohui; Liu, Yueju; Pan, Shuo; Cao, Huijian; Yu, Dahai

2015-03-05

Most surgeons do not fix the lesser trochanter when managing femoral intertrochanteric fractures with intramedullary nails. We have not found any published clinical studies on the relationship between the integrity of the lesser trochanter and surgical outcomes of intertrochanteric fractures treated with intramedullary nails. The purpose of this study was to evaluate the impact of the integrity of the lesser trochanter on the surgical outcome of intertrochanteric fractures. A retrospective review of 85 patients aged more than 60 years with femoral intertrochanteric fractures from January 2010 to July 2012 was performed. The patients were allocated to two groups: those with (n = 37) and without (n = 48) preoperative integrity of the lesser trochanter. Relevant patient variables and medical comorbidities were collected. Medical comorbidities were evaluated according to the American Society of Anesthesiologists classification and medical records were also reviewed for age, sex, time from injury to operation, intraoperative blood loss, volume of transfusion, operative time, length of stay, time to fracture union, Harris Hip Score 1 year postoperatively, and incidence of postoperative complications. Postoperative complications included deep infection (beneath the fascia lata), congestive heart failure, pulmonary embolus, cerebrovascular accident, pneumonia, cardiac arrhythmia, urinary tract infection, wound hematoma, pressure sores, delirium, and deep venous thrombosis. Variables were statistically compared between the two groups, with statistical significance at P<0.05. Patients with and without preoperative integrity of the lesser trochanter were comparable for all assessed clinical variables except fracture type (P < 0.05). There were no statistically significant differences between these groups in time from injury to operation, volume of transfusion, length of stay, time to fracture union, Harris Hip Score at 1 year postoperatively, and incidence of postoperative complication (P > 0.05). The group with preoperative integrity of the lesser trochanter had significantly less blood loss (107.03 ± 49.21 mL) than those without it (133.96 ± 58.08 mL) (P < 0.05) and the operative time was significantly shorter in the former (0.77 ± 0.07 hours) than the latter (0.84 ± 0.11 hours) group (P < 0.05). The integrity of the lesser trochanter has no significant influence on the surgical outcome of intramedullary nail internal fixation of femoral intertrochanteric fractures.

Bio-electrochemical remediation of real field petroleum sludge as an electron donor with simultaneous power generation facilitates biotransformation of PAH: effect of substrate concentration.

PubMed

Chandrasekhar, K; Venkata Mohan, S

2012-04-01

Remediation of real-field petroleum sludge was studied under self-induced electrogenic microenvironment with the function of variable organic loads (OLs) in bio-electrochemical treatment (BET) systems. Operation under various OLs documented marked influence on both electrogenic activity and remediation efficiency. Both total petroleum hydrocarbons (TPH) and its aromatic fraction documented higher removal with OL4 operation followed by OL3, OL2, OL1 and control. Self-induced biopotential and associated multiple bio-electrocatalytic reactions during BET operation facilitated biotransformation of higher ring aromatics (5-6) to lower ring aromatic (2-3) compounds. Asphaltenes and NSO fractions showed negligible removal during BET operation. Higher electrogenic activity was recorded at OL1 (343mV; 53.11mW/m(2), 100Ω) compared to other three OLs operation. Bioaugmentation to anodic microflora with anaerobic culture documented enhanced electrogenic activity at OL4 operation. Voltammetric profiles, Tafel analysis and VFA generation were in agreement with the observed power generation and degradation efficiency. Copyright © 2012 Elsevier Ltd. All rights reserved.

An approach of ionic liquids/lithium salts based microwave irradiation pretreatment followed by ultrasound-microwave synergistic extraction for two coumarins preparation from Cortex fraxini.

PubMed

Liu, Zaizhi; Gu, Huiyan; Yang, Lei

2015-10-23

Ionic liquids/lithium salts solvent system was successfully introduced into the separation technique for the preparation of two coumarins (aesculin and aesculetin) from Cortex fraxini. Ionic liquids/lithium salts based microwave irradiation pretreatment followed by ultrasound-microwave synergy extraction (ILSMP-UMSE) procedure was developed and optimized for the sufficient extraction of these two analytes. Several variables which can potentially influence the extraction yields, including pretreatment time and temperature, [C4mim]Br concentration, LiAc content, ultrasound-microwave synergy extraction (UMSE) time, liquid-solid ratio, and UMSE power were optimized by Plackett-Burman design. Among seven variables, UMSE time, liquid-solid ratio, and UMSE power were the statistically significant variables and these three factors were further optimized by Box-Behnken design to predict optimal extraction conditions and find out operability ranges with maximum extraction yields. Under optimum operating conditions, ILSMP-UMSE showed higher extraction yields of two target compounds than those obtained by reference extraction solvents. Method validation studies also evidenced that ILSMP-UMSE is credible for the preparation of two coumarins from Cortex fraxini. This study is indicative of the proposed procedure that has huge application prospects for the preparation of natural products from plant materials. Copyright © 2015 Elsevier B.V. All rights reserved.

Impact of the European Working Time Directive on exposure to operative cardiac surgical training.

PubMed

Lim, Eric; Tsui, Steven

2006-10-01

To evaluate the impact of the reduced working hours, an anticipated decline in case load and increasing patient risk profile, we performed a cohort study to determine the factors that influenced operative surgical training. A historic cohort study design was utilised, and data were acquired from a prospective operative surgical database a year before, and a year after the introduction of the European Working Time Directive (EWTD) compliant rota (1st August 2004). Logistic regression was used to determine the predictors of operative surgical training, and individual variables were ranked by likelihood ratio. In total, 3312 cardiac surgical operations were performed over a 2-year period between 3rd August 2003 and 31st July 2005. The proportion of cases performed by trainees was 39% (626/1587) in the year before and 40% (695/1725) in the year after the introduction of WTD compliant rota. There were no differences in operative risk (logistic EuroSCORE of 8, P=0.853). Independent predictors for surgery performed by a trainee (in descending order of influence) were the consultant in charge (chi11(2) 273.1; P<0.001), procedure performed (chi5(2) 163.5; P<0.001), increasing seniority of trainee (chi2(2) 142.3; P<0.001), revision surgery (chi1(2) 45.9; P<0.001), lower EuroSCORE (chi1(2) 17.6; P<0.001), and better ventricular function (chi2(2) 7.8; P=0.020). The odds ratio of an operation performed by a trainee increased after the introduction of the EWTD compliant rota to 1.19 (95% CI 1.00-1.41; P=0.045). With a successful institution-specific training module and a commitment to training, exposure to operative surgical training can be sustained despite shortening of working hours.

Results of Database Studies in Spine Surgery Can Be Influenced by Missing Data.

PubMed

Basques, Bryce A; McLynn, Ryan P; Fice, Michael P; Samuel, Andre M; Lukasiewicz, Adam M; Bohl, Daniel D; Ahn, Junyoung; Singh, Kern; Grauer, Jonathan N

2017-12-01

National databases are increasingly being used for research in spine surgery; however, one limitation of such databases that has received sparse mention is the frequency of missing data. Studies using these databases often do not emphasize the percentage of missing data for each variable used and do not specify how patients with missing data are incorporated into analyses. This study uses the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database to examine whether different treatments of missing data can influence the results of spine studies. (1) What is the frequency of missing data fields for demographics, medical comorbidities, preoperative laboratory values, operating room times, and length of stay recorded in ACS-NSQIP? (2) Using three common approaches to handling missing data, how frequently do those approaches agree in terms of finding particular variables to be associated with adverse events? (3) Do different approaches to handling missing data influence the outcomes and effect sizes of an analysis testing for an association with these variables with occurrence of adverse events? Patients who underwent spine surgery between 2005 and 2013 were identified from the ACS-NSQIP database. A total of 88,471 patients undergoing spine surgery were identified. The most common procedures were anterior cervical discectomy and fusion, lumbar decompression, and lumbar fusion. Demographics, comorbidities, and perioperative laboratory values were tabulated for each patient, and the percent of missing data was noted for each variable. These variables were tested for an association with "any adverse event" using three separate multivariate regressions that used the most common treatments for missing data. In the first regression, patients with any missing data were excluded. In the second regression, missing data were treated as a negative or "reference" value; for continuous variables, the mean of each variable's reference range was computed and imputed. In the third regression, any variables with > 10% rate of missing data were removed from the regression; among variables with ≤ 10% missing data, individual cases with missing values were excluded. The results of these regressions were compared to determine how the different treatments of missing data could affect the results of spine studies using the ACS-NSQIP database. Of the 88,471 patients, as many as 4441 (5%) had missing elements among demographic data, 69,184 (72%) among comorbidities, 70,892 (80%) among preoperative laboratory values, and 56,551 (64%) among operating room times. Considering the three different treatments of missing data, we found different risk factors for adverse events. Of 44 risk factors found to be associated with adverse events in any analysis, only 15 (34%) of these risk factors were common among the three regressions. The second treatment of missing data (assuming "normal" value) found the most risk factors (40) to be associated with any adverse event, whereas the first treatment (deleting patients with missing data) found the fewest associations at 20. Among the risk factors associated with any adverse event, the 10 with the greatest effect size (odds ratio) by each regression were ranked. Of the 15 variables in the top 10 for any regression, six of these were common among all three lists. Differing treatments of missing data can influence the results of spine studies using the ACS-NSQIP. The current study highlights the importance of considering how such missing data are handled. Until there are better guidelines on the best approaches to handle missing data, investigators should report how missing data were handled to increase the quality and transparency of orthopaedic database research. Readers of large database studies should note whether handling of missing data was addressed and consider potential bias with high rates or unspecified or weak methods for handling missing data.

Testing of a Loop Heat Pipe Subjective to Variable Accelerations. Part 2; Temperature Stability

NASA Technical Reports Server (NTRS)

Ku, Jentung; Ottenstein, Laura; Kaya, Taril; Rogers, Paul; Hoff, Craig

2000-01-01

The effect of accelerating forces on the performance of loop heat pipes (LHP) is of interest and importance to terrestrial and space applications. LHP's are being considered for cooling of military combat vehicles and for spinning spacecraft. In order to investigate the effect of an accelerating force on LHP operation, a miniature LHP was installed on a spin table. Variable accelerating forces were imposed on the LHP by spinning the table at different angular speeds. Several patterns of accelerating forces were applied, i.e. continuous spin at different speeds and periodic spin at different speeds and frequencies. The resulting accelerations ranged from 1.17 g's to 4.7 g's. This paper presents the second part of the experimental study, i.e. the effect of an accelerating force on the LHP operating temperature. It has been known that in stationary tests the LHP operating temperature is a function of the evaporator power and the condenser sink temperature when the compensation temperature is not actively controlled. Results of this test program indicate that any change in the accelerating force will result in a chance in the LHP operating temperature through its influence on the fluid distribution in the evaporator, condenser and compensation chamber. However, the effect is not universal, rather it is a function of other test conditions. A steady, constant acceleration may result in an increase or decrease of the operating temperature, while a periodic spin will lead to a quasi-steady operating temperature over a sufficient time interval. In addition, an accelerating force may lead to temperature hysteresis and changes in the temperature oscillation. In spite of all these effects, the LHP continued to operate without any problems in all tests.

Rules and regulations as potential moderator on the relationship between organizational internal and external factors with effective construction risk management in Nigerian construction companies: A proposed framework

NASA Astrophysics Data System (ADS)

Adeleke, A. Q.; Bahaudin, A. Y.; Kamaruddeen, A. M.

2016-08-01

Certain organizational internal and external factors have been found to influence effective construction risk management within the construction company which has contributed to massive risk occurrence on the projects. Yet, the influence of the organizational factors such as effective communication, team competency with skills, active leadership, political factor, organizational culture, technology factor and economic factor on effective construction risk management among the construction companies operating in Abuja and Lagos state Nigeria have not received considerable attention. More so, a moderating variable is proposed. This paper proposes rules and regulations as the potential moderator on the relationship between organisational internal factors, external factors and effective construction risk management.

Discoveries about Tropospheric Ozone Pollution from Satellite and Sounding

NASA Technical Reports Server (NTRS)

Thompson, Anne M.

2004-01-01

We have been producing near-real time tropospheric ozone satellite maps from the TOMS (Total Ozone Mapping Spectrometer) sensor since 1997. This is most readily done for the tropics, where the stratospheric and tropospheric ozone column amounts can be discriminated readily. Maps for 1996-2000 for the operational Earth-Probe instrument reside at: chttp://www.atmos.umd.edu/-trope>. Pollution in the tropics is influenced by biomass burning and by transport patterns that favor recirculation and in other cases reflect climate variability like the El-Nino-Southern Oscillation [Thompson et al., 2001]. Time permitting, examples of mid-latitude, intercontinental transport of ozone pollution sensed by TOMS will be shown. The satellite view of chemical-dynamical interactions in tropospheric ozone is not adequate to capture vertical variability. Thus, in 1998, NASA's Goddard Space Flight Center and a team of international sponsors established the SHADOZ (Southern Hemisphere ADditional OZonesondes) project to address the gap in tropical ozone soundings. SHADOZ augments launches and provides a public archive of ozonesonde data from twelve tropical stations at http://croc.gsfc.nasa.gov/shadoz. Further insights into the role of chemical and dynamical influences have emerged from the first 4-5 years of SHADOZ data (less than 2000 ozone profiles): (a) highly variable tropospheric ozone; (b) a zonal wave-one pattern in tropospheric column ozone; (c) convective variability affects tropospheric ozone over the Indian and Pacific Ocean; (d) a "tropical Atlantic Paradox" appears in December-January-February.

The grit effect: predicting retention in the military, the workplace, school and marriage

PubMed Central

Eskreis-Winkler, Lauren; Shulman, Elizabeth P.; Beal, Scott A.; Duckworth, Angela L.

2013-01-01

Remaining committed to goals is necessary (albeit not sufficient) to attaining them, but very little is known about domain-general individual differences that contribute to sustained goal commitment. The current investigation examines the association between grit, defined as passion and perseverance for long-term goals, other individual difference variables, and retention in four different contexts: the military, workplace sales, high school, and marriage. Grit predicted retention over and beyond established context-specific predictors of retention (e.g., intelligence, physical aptitude, Big Five personality traits, job tenure) and demographic variables in each setting. Grittier soldiers were more likely to complete an Army Special Operations Forces (ARSOF) selection course, grittier sales employees were more likely to keep their jobs, grittier students were more likely to graduate from high school, and grittier men were more likely to stay married. The relative predictive validity of grit compared to other traditional predictors of retention is examined in each of the four studies. These findings suggest that in addition to domain-specific influences, there may be domain-general individual differences which influence commitment to diverse life goals over time. PMID:24550863

The grit effect: predicting retention in the military, the workplace, school and marriage.

PubMed

Eskreis-Winkler, Lauren; Shulman, Elizabeth P; Beal, Scott A; Duckworth, Angela L

2014-01-01

Remaining committed to goals is necessary (albeit not sufficient) to attaining them, but very little is known about domain-general individual differences that contribute to sustained goal commitment. The current investigation examines the association between grit, defined as passion and perseverance for long-term goals, other individual difference variables, and retention in four different contexts: the military, workplace sales, high school, and marriage. Grit predicted retention over and beyond established context-specific predictors of retention (e.g., intelligence, physical aptitude, Big Five personality traits, job tenure) and demographic variables in each setting. Grittier soldiers were more likely to complete an Army Special Operations Forces (ARSOF) selection course, grittier sales employees were more likely to keep their jobs, grittier students were more likely to graduate from high school, and grittier men were more likely to stay married. The relative predictive validity of grit compared to other traditional predictors of retention is examined in each of the four studies. These findings suggest that in addition to domain-specific influences, there may be domain-general individual differences which influence commitment to diverse life goals over time.

Drivers of long-term precipitation and runoff variability in the southeastern USA

NASA Astrophysics Data System (ADS)

Engström, Johanna; Waylen, Peter

2018-02-01

The hydroclimatology of the southeastern USA (AL, GA, NC, SC, and TN) is analyzed from a holistic perspective, including multiple climate drivers. Monthly precipitation modeled by the PRISM group and runoff data (1952-2011) from 18 basins are analyzed using a single-field based principal component's analysis. Results indicate that the Atlantic Multidecadal Oscillation and El Niño-Southern Oscillation are the main atmospheric drivers of hydroclimate variability in the region, sometimes operating at several months' lag. Their influence is the strongest in the fall through spring, which corresponds with the dry season in the southern parts of the study area thereby increasing pressure on already limited water resources. The Arctic Oscillation, North Atlantic Oscillation, and Pacific-North American patterns vary on shorter-term bases, and also show a significant, but temporally more sporadic influence. Insight is also brought to the ongoing discussion, confirming the disassociation of the Arctic and North Atlantic Oscillation. Findings can be used in water resources forecasting, giving an indication of expected water volumes several months ahead.

The influence of economic incentives linked to road safety indicators on accidents: the case of toll concessions in Spain.

PubMed

Rangel, Thais; Vassallo, José Manuel; Herraiz, Israel

2013-10-01

The goal of this paper is to evaluate whether the incentives incorporated in toll highway concession contracts in order to encourage private operators to adopt measures to reduce accidents are actually effective at improving safety. To this end, we implemented negative binomial regression models using information about highway characteristics and accident data from toll highway concessions in Spain from 2007 to 2009. Our results show that even though road safety is highly influenced by variables that are not managed by the contractor, such as the annual average daily traffic (AADT), the percentage of heavy vehicles on the highway, number of lanes, number of intersections and average speed; the implementation of these incentives has a positive influence on the reduction of accidents and injuries. Consequently, this measure seems to be an effective way of improving safety performance in road networks. Copyright © 2013 Elsevier Ltd. All rights reserved.

New Best-Practices Guide for Photovoltaic System Operations and Maintenance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fact sheet summarizing technical report TP-7A40-67553. As solar photovoltaic (PV) systems have continued their transition from niche applications into large, mature markets in the United States, their potential as financial investments has risen accordingly. Mainstream investors, however, need to feel confident about the risk and return of solar photovoltaic (PV) systems before committing funds. A major influence on risk and return for PV is operations and maintenance (O&M) - but O&M practices and costs vary widely across the United States, making these variables difficult for investors to predict. To address this barrier to continued PV investment, the PV O&M Workingmore » Group has developed a new best-practices guide for PV O&M.« less

Biodemographic Modeling of the Links Between Fertility Motivation and Fertility Outcomes in the NLSY79

PubMed Central

MILLER, WARREN B.; BARD, DAVID E.; PASTA, DAVID J.; RODGERS, JOSEPH LEE

2010-01-01

In spite of long-held beliefs that traits related to reproductive success tend to become fixed by evolution with little or no genetic variation, there is now considerable evidence that the natural variation of fertility within populations is genetically influenced and that a portion of that influence is related to the motivational precursors to fertility. We conduct a two-stage analysis to examine these inferences in a time-ordered multivariate context. First, using data from the National Longitudinal Survey of Youth, 1979, and LISREL analysis, we develop a structural equation model in which five hypothesized motivational precursors to fertility, measured in 1979–1982, predict both a child-timing and a child-number outcome, measured in 2002. Second, having chosen two time-ordered sequences of six variables from the SEM to represent our phenotypic models, we use Mx to conduct both univariate and multivariate behavioral genetic analyses with the selected variables. Our results indicate that one or more genes acting within a gene network have additive effects that operate through child-number desires to affect both the timing of the next child born and the final number of children born, that one or more genes acting through a separate network may have additive effects operating through gender role attitudes to produce downstream effects on the two fertility outcomes, and that no genetic variance is associated with either child-timing intentions or educational intentions. PMID:20608103

Job stress, unwinding and drinking in transit operators.

PubMed

Delaney, William P; Grube, Joel W; Greiner, Birgit; Fisher, June M; Ragland, David R

2002-07-01

This study tests the spillover model of the effects of work stress on after-work drinking, using the variable "length of time to unwind" as a mediator. A total of 1,974 transit operators were contacted and 1,553 (79%) of them participated in a personal interview. Complete data on the variables in this analysis were available for 1,208 respondents (84% men). Using latent variable structural equation modeling, a model was tested that predicted that daily job problems, skipped meals and less social support from supervisor would increase alcohol consumption through the mediator, length of time to unwind and relax after work. Increased alcohol consumption was, in turn, hypothesized to increase drinking problems. As predicted, skipped meals and daily job problems increased length of time to unwind and had an indirect positive relationship with overall drinking, even when controlling for drinking norms and demographic variables. Overall drinking was positively associated with drinking problems. Supervisor support at work, however, did not significantly influence length of time to unwind. Difficulty unwinding (longer time to unwind) did not have direct effects on drinking problems; however, indirect effects through overall drinking were observed. These results provide preliminary support for the mediating role of length of time to unwind and relax after work in a spillover model of the stress-drinking relationship. This research introduces a new mediator and empirical links between job problems, length of time to unwind, drinking and drinking problems, which ground more substantively the domains of work stress and alcohol consumption.

Addressing drug adherence using an operations management model.

PubMed

Nunlee, Martin; Bones, Michelle

2014-01-01

OBJECTIVE To provide a model that enables health systems and pharmacy benefit managers to provide medications reliably and test for reliability and validity in the analysis of adherence to drug therapy of chronic disease. SUMMARY The quantifiable model described here can be used in conjunction with behavioral designs of drug adherence assessments. The model identifies variables that can be reproduced and expanded across the management of chronic diseases with drug therapy. By creating a reorder point system for reordering medications, the model uses a methodology commonly seen in operations research. The design includes a safety stock of medication and current supply of medication, which increases the likelihood that patients will have a continuous supply of medications, thereby positively affecting adherence by removing barriers. CONCLUSION This method identifies an adherence model that quantifies variables related to recommendations from health care providers; it can assist health care and service delivery systems in making decisions that influence adherence based on the expected order cycle days and the expected daily quantity of medication administered. This model addresses the possession of medication as a barrier to adherence.

Evaluation of corrosion inhibitor simulating conditions of operation

NASA Astrophysics Data System (ADS)

Gómez, O.; Aponte, H.; Vera, E.; Pineda, Y.

2017-12-01

Operating conditions at the head of oil wells are critical, in addition to injecting water to increase the pressure while maintaining production cause deterioration in the metallic structures that transport fluids. One way to maintain integrity is the injection of inhibitors which plays an important role in protecting the pipes. In this study a molecule N-PHENYL NITRONE was obtained, which was evaluated by electrochemical tests (LPR) and Tafel Polarization Curves in a reactor controlling environments containing different dosages, pressure values, temperatures and flow velocity using working electrodes tubing API N 80, the reactor was connected to a potentiostat to determine corrosion rates, allowing the analysis of the influence of each variable on the protective behaviour of the inhibitor, and its efficiency against the decrease of the deterioration of the pipes. Corrosion products are analysed by X-Ray Diffraction (XRD). Photographic records of the surface verify the formation of iron carbonate (FeCO3). In addition, a mathematical analysis of the independent variables is performed to evaluate the effect that it has on the efficiency of corrosion inhibition.

Technician Consistency in Specular Microscopy Measurements: A "Real-World" Retrospective Analysis of a United States Eye Bank.

PubMed

Rand, Gabriel M; Kwon, Ji Won; Gore, Patrick K; McCartney, Mitchell D; Chuck, Roy S

2017-10-01

To quantify consistency of endothelial cell density (ECD) measurements among technicians in a single US eye bank operating under typical operating conditions. In this retrospective analysis of 51 microscopy technicians using a semiautomated counting method on 35,067 eyes from July 2007 to May 2015, technician- and date-related marginal ECD effects were calculated using linear regression models. ECD variance was correlated with the number of specular microscopy technicians. Technician mean ECDs ranged from 2386 ± 431 to 3005 ± 560 cells/mm. Nine technicians had statistically and clinically significant marginal effects. Annual mean ECDs adjusted for changes in technicians ranged from 2422 ± 433 to 2644 ± 430 cells/mm. The period of 2007 to 2009 had statistically and clinically significant marginal effects. There was a nonstatistically significant association between the number of technicians and ECD standard deviation. There was significant ECD variability associated with specular microscopy technicians and with the date of measurement. We recommend that eye banks collect data related to laboratory factors that have been shown to influence ECD variability.

Hybrid intelligent monironing systems for thermal power plant trips

NASA Astrophysics Data System (ADS)

Barsoum, Nader; Ismail, Firas Basim

2012-11-01

Steam boiler is one of the main equipment in thermal power plants. If the steam boiler trips it may lead to entire shutdown of the plant, which is economically burdensome. Early boiler trips monitoring is crucial to maintain normal and safe operational conditions. In the present work two artificial intelligent monitoring systems specialized in boiler trips have been proposed and coded within the MATLAB environment. The training and validation of the two systems has been performed using real operational data captured from the plant control system of selected power plant. An integrated plant data preparation framework for seven boiler trips with related operational variables has been proposed for IMSs data analysis. The first IMS represents the use of pure Artificial Neural Network system for boiler trip detection. All seven boiler trips under consideration have been detected by IMSs before or at the same time of the plant control system. The second IMS represents the use of Genetic Algorithms and Artificial Neural Networks as a hybrid intelligent system. A slightly lower root mean square error was observed in the second system which reveals that the hybrid intelligent system performed better than the pure neural network system. Also, the optimal selection of the most influencing variables performed successfully by the hybrid intelligent system.

The human factors of workstation telepresence

NASA Technical Reports Server (NTRS)

Smith, Thomas J.; Smith, Karl U.

1990-01-01

The term workstation telepresence has been introduced to describe human-telerobot compliance, which enables the human operator to effectively project his/her body image and behavioral skills to control of the telerobot itself. Major human-factors considerations for establishing high fidelity workstation telepresence during human-telerobot operation are discussed. Telerobot workstation telepresence is defined by the proficiency and skill with which the operator is able to control sensory feedback from direct interaction with the workstation itself, and from workstation-mediated interaction with the telerobot. Numerous conditions influencing such control have been identified. This raises the question as to what specific factors most critically influence the realization of high fidelity workstation telepresence. The thesis advanced here is that perturbations in sensory feedback represent a major source of variability in human performance during interactive telerobot operation. Perturbed sensory feedback research over the past three decades has established that spatial transformations or temporal delays in sensory feedback engender substantial decrements in interactive task performance, which training does not completely overcome. A recently developed social cybernetic model of human-computer interaction can be used to guide this approach, based on computer-mediated tracking and control of sensory feedback. How the social cybernetic model can be employed for evaluating the various modes, patterns, and integrations of interpersonal, team, and human-computer interactions which play a central role is workstation telepresence are discussed.

Analysis 320 coal mine accidents using structural equation modeling with unsafe conditions of the rules and regulations as exogenous variables.

PubMed

Zhang, Yingyu; Shao, Wei; Zhang, Mengjia; Li, Hejun; Yin, Shijiu; Xu, Yingjun

2016-07-01

Mining has been historically considered as a naturally high-risk industry worldwide. Deaths caused by coal mine accidents are more than the sum of all other accidents in China. Statistics of 320 coal mine accidents in Shandong province show that all accidents contain indicators of "unsafe conditions of the rules and regulations" with a frequency of 1590, accounting for 74.3% of the total frequency of 2140. "Unsafe behaviors of the operator" is another important contributory factor, which mainly includes "operator error" and "venturing into dangerous places." A systems analysis approach was applied by using structural equation modeling (SEM) to examine the interactions between the contributory factors of coal mine accidents. The analysis of results leads to three conclusions. (i) "Unsafe conditions of the rules and regulations," affect the "unsafe behaviors of the operator," "unsafe conditions of the equipment," and "unsafe conditions of the environment." (ii) The three influencing factors of coal mine accidents (with the frequency of effect relation in descending order) are "lack of safety education and training," "rules and regulations of safety production responsibility," and "rules and regulations of supervision and inspection." (iii) The three influenced factors (with the frequency in descending order) of coal mine accidents are "venturing into dangerous places," "poor workplace environment," and "operator error." Copyright © 2016 Elsevier Ltd. All rights reserved.

[Electric traction magnetic fields of ultra-low frequency as an occupational risk factor of ischemic heart disease].

PubMed

Ptitsyna, N G; Kudrin, V A; Villorezi, D; Kopytenko, Iu A; Tiasto, M I; Kopytenko, E A; Bochko, V A; Iuchchi, N

1996-01-01

The study was inspired by earlier results that displayed influence of variable natural geomagnetic field (0.005-10 Hz range-ultra-low frequencies) on circulatory system, indicated possible correlation between industrial ultra-low frequency fields and prevalence of myocardial infarction. The authors conducted unique measurements of ultra-low frequency fields produced by electric engines. The results were compared with data on morbidity among railway transport workers. The findings are that level of magnetic variations in electric locomotive cabin can exceed 280 micro Tesla, whereas that in car sections reaches 50 micro Tesla. Occurrence of coronary heart disease among the locomotive operators appeared to be 2.0 + 0.2 times higher than that among the car section operators. Higher risk of coronary heart disease in the locomotive operators is associated with their increased occupational magnetic load.

A simplified model to evaluate the effect of fluid rheology on non-Newtonian flow in variable aperture fractures

NASA Astrophysics Data System (ADS)

Felisa, Giada; Ciriello, Valentina; Longo, Sandro; Di Federico, Vittorio

2017-04-01

Modeling of non-Newtonian flow in fractured media is essential in hydraulic fracturing operations, largely used for optimal exploitation of oil, gas and thermal reservoirs. Complex fluids interact with pre-existing rock fractures also during drilling operations, enhanced oil recovery, environmental remediation, and other natural phenomena such as magma and sand intrusions, and mud volcanoes. A first step in the modeling effort is a detailed understanding of flow in a single fracture, as the fracture aperture is typically spatially variable. A large bibliography exists on Newtonian flow in single, variable aperture fractures. Ultimately, stochastic modeling of aperture variability at the single fracture scale leads to determination of the flowrate under a given pressure gradient as a function of the parameters describing the variability of the aperture field and the fluid rheological behaviour. From the flowrate, a flow, or 'hydraulic', aperture can then be derived. The equivalent flow aperture for non-Newtonian fluids of power-law nature in single, variable aperture fractures has been obtained in the past both for deterministic and stochastic variations. Detailed numerical modeling of power-law fluid flow in a variable aperture fracture demonstrated that pronounced channelization effects are associated to a nonlinear fluid rheology. The availability of an equivalent flow aperture as a function of the parameters describing the fluid rheology and the aperture variability is enticing, as it allows taking their interaction into account when modeling flow in fracture networks at a larger scale. A relevant issue in non-Newtonian fracture flow is the rheological nature of the fluid. The constitutive model routinely used for hydro-fracturing modeling is the simple, two-parameter power-law. Yet this model does not characterize real fluids at low and high shear rates, as it implies, for shear-thinning fluids, an apparent viscosity which becomes unbounded for zero shear rate and tends to zero for infinite shear rate. On the contrary, the four-parameter Carreau constitutive equation includes asymptotic values of the apparent viscosity at those limits; in turn, the Carreau rheological equation is well approximated by the more tractable truncated power-law model. Results for flow of such fluids between parallel walls are already available. This study extends the adoption of the truncated power-law model to variable aperture fractures, with the aim of understanding the joint influence of rheology and aperture spatial variability. The aperture variation, modeled within a stochastic or deterministic framework, is taken to be one-dimensional and perpendicular to the flow direction; for stochastic modeling, the influence of different distribution functions is examined. Results are then compared with those obtained for pure power-law fluids for different combinations of model parameters. It is seen that the adoption of the pure power law model leads to significant overestimation of the flowrate with respect to the truncated model, more so for large external pressure gradient and/or aperture variability.

Analysis of amorphous indium-gallium-zinc-oxide thin-film transistor contact metal using Pilling-Bedworth theory and a variable capacitance diode model

NASA Astrophysics Data System (ADS)

Kiani, Ahmed; Hasko, David G.; Milne, William I.; Flewitt, Andrew J.

2013-04-01

It is widely reported that threshold voltage and on-state current of amorphous indium-gallium-zinc-oxide bottom-gate thin-film transistors are strongly influenced by the choice of source/drain contact metal. Electrical characterisation of thin-film transistors indicates that the electrical properties depend on the type and thickness of the metal(s) used. Electron transport mechanisms and possibilities for control of the defect state density are discussed. Pilling-Bedworth theory for metal oxidation explains the interaction between contact metal and amorphous indium-gallium-zinc-oxide, which leads to significant trap formation. Charge trapping within these states leads to variable capacitance diode-like behavior and is shown to explain the thin-film transistor operation.

Free jet feasibility study of a thermal acoustic shield concept for AST/VCE application-dual flow. Comprehensive data report. Volume 1: Test nozzles and acoustic data

NASA Technical Reports Server (NTRS)

Janardan, B. A.; Brausch, J. F.; Price, A. O.

1984-01-01

Acoustic and diagnostic data that were obtained to determine the influence of selected geometric and aerodynamic flow variables of coannular nozzles with thermal acoustic shields are summarized in this comprehensive data report. A total of 136 static and simulated flight acoustic test points were conducted with 9 scale-model nozzles The tested nozzles included baseline (unshielded), 180 deg shielded, and 360 deg shielded dual flow coannular plug configurations. The baseline configurations include a high radius ratio unsuppressed coannular plug nozzle and a coanuular plug nozzle and a coannular plug nozzle with a 20-chute outer stream suppressor. The tests were conducted at nozzle temperatures and pressure typical of operating conditions of variable cycle engine.

Alzheimer disease identification using amyloid imaging and reserve variables

PubMed Central

Roe, C.M.; Mintun, M.A.; Ghoshal, N.; Williams, M.M.; Grant, E.A.; Marcus, D.S.; Morris, J.C.

2010-01-01

Objective: Several factors may influence the relationship between Alzheimer disease (AD) lesions and the expression of dementia, including those related to brain and cognitive reserve. Other factors may confound the association between AD pathology and dementia. We tested whether factors thought to influence the association of AD pathology and dementia help to accurately identify dementia of the Alzheimer type (DAT) when considered together with amyloid imaging. Methods: Participants with normal cognition (n = 180) and with DAT (n = 25), aged 50 years or older, took part in clinical, neurologic, and psychometric assessments. PET with the Pittsburgh compound B (PiB) tracer was used to measure brain amyloid, yielding a mean cortical binding potential (MCBP) reflecting PiB uptake. Logistic regression was used to generate receiver operating characteristic curves, and the areas under those curves (AUC), to compare the predictive accuracy of using MCBP alone vs MCBP together with other variables selected using a stepwise selection procedure to identify participants with DAT vs normal cognition. Results: The AUC resulting from MCBP alone was 0.84 (95% confidence interval [CI] = 0.73–0.94; cross-validated AUC = 0.80, 95% CI = 0.68–0.92). The AUC for the predictive equation generated by a stepwise model including education, normalized whole brain volume, physical health rating, gender, and use of medications that may interfere with cognition was 0.94 (95% CI = 0.90–0.98; cross-validated AUC = 0.91, 95% CI = 0.85–0.96), an improvement (p = 0.025) over that yielded using MCBP alone. Conclusion: Results suggest that factors reported to influence associations between AD pathology and dementia can improve the predictive accuracy of amyloid imaging for the identification of symptomatic AD. GLOSSARY A β = amyloid-β; AD = Alzheimer disease; AUC = area under receiver operating characteristic curve; BP = binding potential; CDR = Clinical Dementia Rating; CI = confidence interval; DAT = dementia of the Alzheimer type; DV = distribution volume; MCBP = mean cortical binding potential; nWBV = normalized whole brain volume; OR = odds ratio; PiB = Pittsburgh compound B; ROC = receiver operating characteristic curve; ROI = region of interest. PMID:20603484

Climatic extremes improve predictions of spatial patterns of tree species

USGS Publications Warehouse

Zimmermann, N.E.; Yoccoz, N.G.; Edwards, T.C.; Meier, E.S.; Thuiller, W.; Guisan, Antoine; Schmatz, D.R.; Pearman, P.B.

2009-01-01

Understanding niche evolution, dynamics, and the response of species to climate change requires knowledge of the determinants of the environmental niche and species range limits. Mean values of climatic variables are often used in such analyses. In contrast, the increasing frequency of climate extremes suggests the importance of understanding their additional influence on range limits. Here, we assess how measures representing climate extremes (i.e., interannual variability in climate parameters) explain and predict spatial patterns of 11 tree species in Switzerland. We find clear, although comparably small, improvement (+20% in adjusted D2, +8% and +3% in cross-validated True Skill Statistic and area under the receiver operating characteristics curve values) in models that use measures of extremes in addition to means. The primary effect of including information on climate extremes is a correction of local overprediction and underprediction. Our results demonstrate that measures of climate extremes are important for understanding the climatic limits of tree species and assessing species niche characteristics. The inclusion of climate variability likely will improve models of species range limits under future conditions, where changes in mean climate and increased variability are expected.

An examination of loads and responses of a wind turbine undergoing variable-speed operation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wright, A.D.; Buhl, M.L. Jr.; Bir, G.S.

1996-11-01

The National Renewable Energy Laboratory has recently developed the ability to predict turbine loads and responses for machines undergoing variable-speed operation. The wind industry has debated the potential benefits of operating wind turbine sat variable speeds for some time. Turbine system dynamic responses (structural response, resonance, and component interactions) are an important consideration for variable-speed operation of wind turbines. The authors have implemented simple, variable-speed control algorithms for both the FAST and ADAMS dynamics codes. The control algorithm is a simple one, allowing the turbine to track the optimum power coefficient (C{sub p}). The objective of this paper is tomore » show turbine loads and responses for a particular two-bladed, teetering-hub, downwind turbine undergoing variable-speed operation. The authors examined the response of the machine to various turbulent wind inflow conditions. In addition, they compare the structural responses under fixed-speed and variable-speed operation. For this paper, they restrict their comparisons to those wind-speed ranges for which limiting power by some additional control strategy (blade pitch or aileron control, for example) is not necessary. The objective here is to develop a basic understanding of the differences in loads and responses between the fixed-speed and variable-speed operation of this wind turbine configuration.« less

Comparison between variable and constant rotor speed operation on WINDMEL-II

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sasamoto, Akira; Matsumiya, Hikaru; Kawamura, Shunji

1996-10-01

On a wind turbine control system for rotor revolution speed, it is believed that variable speed operation has the advantages over constant speed from a view point of both aerodynamics and mechanics. However, there is no experimental study which shows the differences. In this report, the authors intend to clarify the differences about shaft torque by using experimental data, from a new wind turbine system which has both variable and constant operation. The result in observation of the experimental data shows that variable speed operational shaft torque is lower than constant speed operational one.

Variability as a Subject Matter in a Science of Behavior: Reply to Commentaries

ERIC Educational Resources Information Center

Barba, Lourenco de Souza

2012-01-01

In his article, the author claimed that studies of operant variability that use a lag-"n" or threshold procedure and measure the obtained variability through the change in U value fail to provide direct evidence that variability is an operant dimension of behavior. To do so, he adopted Catania's (1973) concept of the operant, which takes the…

Influence of malnutrition on cognitive development assessed by Piagetian tasks.

PubMed

Agarwal, D K; Upadhyay, S K; Agarwal, K N

1989-01-01

Cognitive development of 1336 children (6-8 yr) was studied in relation to their nutritional status. Seven Piagetian tasks covering the mental process of a concrete operational period were given to each child to assess the cognitive development. Weschler intelligence scale for Indian Children was used to assess the IQ of each child. The percentage of malnourished children in stage I of development (preoperational) was significantly higher as that of wellnourished children. A higher percentage of children in the latter group was in stage III of development (concrete operation). In boys performance on all the tasks was influenced by undernutrition except for class inclusion. In girls this was true only for conservation of liquid, substance and ordinal relation. The results of the regression analysis showed that nutrition was the only factor weakly associated with the poor performance of the children in various tasks. Further, the effect of nutrition was more pronounced in conservation tasks indicating poor verbal reasoning and comprehension in malnourished children. Information was also collected regarding the parental education and occupation, socio-economic status, caste, economic sufficiency, psychosocial stimulation and home environment. However, these environmental factors did not influence the development of rural children. This might be due to the fact that the population in the present study did not vary much with regard to these variables.

Quantifying variability in removal efficiencies of chemicals in activated sludge wastewater treatment plants - a meta-analytical approach.

PubMed

Douziech, Mélanie; Conesa, Irene Rosique; Benítez-López, Ana; Franco, Antonio; Huijbregts, Mark; van Zelm, Rosalie

2018-01-24

Large variations in removal efficiencies (REs) of chemicals have been reported for monitoring studies of activated sludge wastewater treatment plants (WWTPs). In this work, we conducted a meta-analysis on REs (1539 data points) for a set of 209 chemicals consisting of fragrances, surfactants, and pharmaceuticals in order to assess the drivers of the variability relating to inherent properties of the chemicals and operational parameters of activated sludge WWTPs. For a reduced dataset (n = 542), we developed a mixed-effect model (meta-regression) to explore the observed variability in REs for the chemicals using three chemical specific factors and four WWTP-related parameters. The overall removal efficiency of the set of chemicals was 82.1% (95% CI 75.2-87.1%, N = 1539). Our model accounted for 17% of the total variability in REs, while the process-based model SimpleTreat did not perform better than the average of the measured REs. We identified that, after accounting for other factors potentially influencing RE, readily biodegradable compounds were better removed than non-readily biodegradable ones. Further, we showed that REs increased with increasing sludge retention times (SRTs), especially for non-readily biodegradable compounds. Finally, our model highlighted a decrease in RE with increasing K OC . The counterintuitive relationship to K OC stresses the need for a better understanding of electrochemical interactions influencing the RE of ionisable chemicals. In addition, we highlighted the need to improve the modelling of chemicals that undergo deconjugation when predicting RE. Our meta-analysis represents a first step in better explaining the observed variability in measured REs of chemicals. It can be of particular help to prioritize the improvements required in existing process-based models to predict removal efficiencies of chemicals in WWTPs.

Psychological theory in an interdisciplinary context: psychological, demographic, health-related, social, and environmental correlates of physical activity in a representative cohort of community-dwelling older adults.

PubMed

Sniehotta, Falko F; Gellert, Paul; Witham, Miles D; Donnan, Peter T; Crombie, Iain K; McMurdo, Marion E T

2013-09-08

Physical activity (PA) in older adults is influenced by a range of environmental, demographic, health-related, social, and psychological variables. Social cognitive psychological models assume that all influences on behaviour operate indirectly through the models constructs, i.e., via intention and self-efficacy. We evaluated direct, indirect, and moderating relationships of a broad range of external variables with physical activity levels alongside intention and self-efficacy. We performed a cross-sectional survey of a representative and stratified (65-80 and 80+ years; deprived and affluent) sample of 584 community-dwelling people, resident in Scotland. Objectively measured physical activity and questionnaire data were collected. Self-efficacy showed unique relationships with physical activity, controlling for demographic, mental health, social, environmental, and weather variables separately, but the relationship was not significant when controlling for physical health. Overall, results indicating support for a mediation hypothesis, intention and self-efficacy statistically mediate the relationship of most domain variables with physical activity. Moderation analyses show that the relationship between social cognitions and physical activity was stronger for individuals with better physical health and lower levels of socio-economic deprivation. Social cognitive variables reflect a range of known environmental, demographic, health-related and social correlates of physical activity, they mediate the relationships of those correlates with physical activity and account for additional variance in physical activity when external correlates are controlled for, except for the physical health domain. The finding that the social cognition-physical activity relationship is higher for participants with better health and higher levels of affluence raises issues for the applicability of social cognitive models to the most disadvantaged older people.

Prostate weight: an independent predictor for positive surgical margins during robotic-assisted laparoscopic radical prostatectomy.

PubMed

Msezane, Lambda P; Gofrit, Ofer N; Lin, Shang; Shalhav, Arieh L; Zagaja, Gregory P; Zorn, Kevin C

2007-10-01

Pre-operative prediction of pathological stage represents the cornerstone of prostate cancer management. Patient counseling is routinely based on pre-operative PSA, Gleason score and clinical stage. In this study, we evaluated whether prostate weight (PW) is an independent predictor of extracapsular extension (ECE) and positive surgical margin (PSM). Between February 2003 and November 2006, 709 men underwent robotic-assisted laparoscopic radical prostatectomy (RLRP). Pre-operative parameters (patient age, pre-operative PSA, biopsy Gleason score, clinical stage) as well as pathological data (prostate weight, pathological stage) were prospectively gathered after internal-review board (IRB) approval. Evaluation of the influence of these variables on ECE and PSM outcomes were assessed using both univariate and multivariate logistic regression analysis. Mean overall patient age, pre-operative PSA and PW were 59.6 years, 6.5 ng/ml and 52.9 g (range 5.5 g-198.7 g), respectively. Of the 393, 209 and 107 men with PW < 50 g, 50 g-< 70 g and < 70 g, ECE was observed in 20.1%, 15.3% and 9.3%, respectively (p = 0.015). In the same patient cohorts, PSM was observed in 25.4%, 14.4% and 7.5%, respectively (p < 0.001). In a multivariate logistic regression analysis, PW, in addition to pre-operative PSA, biopsy Gleason score and clinical stage, was an independent risk factor for ECE (p < 0.001). Similarly, in multi-variate analysis, PW was observed to be a risk factor for PSM (p < 0.001). PW is an independent predictor of both ECE and PSM, with an inverse relationship having been demonstrated between both variables. PW should be considered when counseling patients with prostate cancer treatment.

Clinical, biochemical and genetic risk factors for 30-day and 5-year mortality in 518 adult patients subjected to cardiopulmonary bypass during cardiac surgery - the INFLACOR study.

PubMed

Kowalik, Maciej Michał; Lango, Romuald; Siondalski, Piotr; Chmara, Magdalena; Brzeziński, Maciej; Lewandowski, Krzysztof; Jagielak, Dariusz; Klapkowski, Andrzej; Rogowski, Jan

2018-04-25

There is increasing evidence that genetic variability influences patients' early morbidity after cardiac surgery performed using cardiopulmonary bypass (CPB). The use of mortality as an outcome measure in cardiac surgical genetic association studies is rare. We publish the 30-day and 5-year survival analyses with focus on pre-, intra-, postoperative variables, biochemical parameters, and genetic variants in the INFLACOR (INFLAmmation in Cardiac OpeRations) cohort. In a prospectively recruited cohort of 518 adult Polish Caucasians, who underwent cardiac surgery in which CPB was used, the clinical data, biochemical parameters, IL-6, soluble ICAM-1, TNFα, soluble E-selectin, and 10 single nucleotide polymorphisms were evaluated for their association with 30-day and 5-year mortality. The 30-day mortality was associated with: pre-operative prothrombin international normalized ratio, intra-operative blood lactate, postoperative serum creatine phosphokinase, and acute kidney injury requiring renal replacement therapy (AKI-RRT) in logistic regression. Factors that determined the 5-year survival included: pre-operative NYHA class, history of peripheral artery disease and severe chronic obstructive pulmonary disease, intra-operative blood transfusion; and postoperative peripheral hypothermia, myocardial infarction, infection, and AKI-RRT in Cox regression. Serum levels of IL-6 and ICAM-1 measured three hours after the operation were associated with 30-day and 5-year mortality, respectively. The ICAM1 rs5498 was associated with 30-day and 5-year survival with borderline significance. Different risk factors determined the early (30-day) and late (5-year) survival after adult cardiac surgery in which cardiopulmonary bypass was used. Future genetic association studies in cardiac surgical patients should account for the identified chronic and perioperative risk factors.

Socio-economic variables influencing mean age at marriage in Karnataka and Kerala.

PubMed

Prakasam, C P; Upadhyay, R B

1985-01-01

"In this paper an attempt was made to study the influence of certain socio-economic variables on the male and the female age at marriage in Karnataka and Kerala [India] for the year 1971. Step-wise regression method has been used to select the predictor variables influencing mean age at marriage. The results reveal that percent female literate...and percent female in labour force...are found to influence female mean age at marriage in Kerala, while the variables for Karnataka were percent female literate..., percent male literate..., and percent urban male population...." excerpt

Experimental study of uncentralized squeeze film dampers

NASA Technical Reports Server (NTRS)

Quinn, R. D.

1983-01-01

The vibration response of a rotor system supported by a squeeze film damper (SFD) was experimentally investigated in order to provide experimental data in support of the Rotor/Stator Interactive Finite Element theoretical development. Part of the investigation required the designing and building of a rotor/SFD system that could operate with or without end seals in order to accommodate different SFD lengths. SFD variables investigated included clearance, eccentricity mass, fluid pressure, and viscosity and temperature. The results show inlet pressure, viscosity and clearance have significant influence on the damper performance and accompanying rotor response.

Elevated temperature and temperature programming in conventional liquid chromatography--fundamentals and applications.

PubMed

Vanhoenacker, Gerd; Sandra, Pat

2006-08-01

Temperature, as a powerful variable in conventional LC is discussed from a fundamental point of view and illustrated with applications from the author's laboratory. Emphasis is given to the influence of temperature on speed, selectivity, efficiency, detectability, and mobile phase composition (green chromatography). The problems accompanying the use of elevated temperature and temperature programming in LC are reviewed and solutions are described. The available stationary phases for high temperature operation are summarized and a brief overview of recent applications reported in the literature is given.

MAMS: High resolution atmospheric moisture/surface properties

NASA Technical Reports Server (NTRS)

Jedlovec, Gary J.; Guillory, Anthony R.; Suggs, Ron; Atkinson, Robert J.; Carlson, Grant S.

1991-01-01

Multispectral Atmospheric Mapping Sensor (MAMS) data collected from a number of U2/ER2 aircraft flights were used to investigate atmospheric and surface (land) components of the hydrologic cycle. Algorithms were developed to retrieve surface and atmospheric geophysical parameters which describe the variability of atmospheric moisture, its role in cloud and storm development, and the influence of surface moisture and heat sources on convective activity. Techniques derived with MAMS data are being applied to existing satellite measurements to show their applicability to regional and large process studies and their impact on operational forecasting.

[Application of spaced retrieval training on patients with dementia].

PubMed

Wu, Hua-Shan; Lin, Li-Chan

2012-10-01

Dementia causes semantic and episodic memory impairments that limit patients' activities of daily living (ADL) and increase caregiver burden. Spaced retrieval training uses repetitive retrieval to strengthen cognitive and motor skills intuitively in mild / moderate dementia patients who retain preserved implicit / non-declarative memory. This article describes and discusses the operative mechanism, influencing variables, and practical applications of spaced retrieval training. We hope this article increases professional understanding and application of this training approach to improve dementia patient ADL and improve quality of life for both caregivers and patients.

Dynamics of changing impacts of tropical Indo-Pacific variability on Indian and Australian rainfall

NASA Astrophysics Data System (ADS)

Li, Ziguang; Cai, Wenju; Lin, Xiaopei

2016-08-01

A positive Indian Ocean Dipole (IOD) and a warm phase of the El Niño-Southern Oscillation (ENSO) reduce rainfall over the Indian subcontinent and southern Australia. However, since the 1980s, El Niño’s influence has been decreasing, accompanied by a strengthening in the IOD’s influence on southern Australia but a reversal in the IOD’s influence on the Indian subcontinent. The dynamics are not fully understood. Here we show that a post-1980 weakening in the ENSO-IOD coherence plays a key role. During the pre-1980 high coherence, ENSO drives both the IOD and regional rainfall, and the IOD’s influence cannot manifest itself. During the post-1980 weak coherence, a positive IOD leads to increased Indian rainfall, offsetting the impact from El Niño. Likewise, the post-1980 weak ENSO-IOD coherence means that El Niño’s pathway for influencing southern Australia cannot fully operate, and as positive IOD becomes more independent and more frequent during this period, its influence on southern Australia rainfall strengthens. There is no evidence to support that greenhouse warming plays a part in these decadal fluctuations.

Dynamics of changing impacts of tropical Indo-Pacific variability on Indian and Australian rainfall.

PubMed

Li, Ziguang; Cai, Wenju; Lin, Xiaopei

2016-08-22

A positive Indian Ocean Dipole (IOD) and a warm phase of the El Niño-Southern Oscillation (ENSO) reduce rainfall over the Indian subcontinent and southern Australia. However, since the 1980s, El Niño's influence has been decreasing, accompanied by a strengthening in the IOD's influence on southern Australia but a reversal in the IOD's influence on the Indian subcontinent. The dynamics are not fully understood. Here we show that a post-1980 weakening in the ENSO-IOD coherence plays a key role. During the pre-1980 high coherence, ENSO drives both the IOD and regional rainfall, and the IOD's influence cannot manifest itself. During the post-1980 weak coherence, a positive IOD leads to increased Indian rainfall, offsetting the impact from El Niño. Likewise, the post-1980 weak ENSO-IOD coherence means that El Niño's pathway for influencing southern Australia cannot fully operate, and as positive IOD becomes more independent and more frequent during this period, its influence on southern Australia rainfall strengthens. There is no evidence to support that greenhouse warming plays a part in these decadal fluctuations.

Modeling of the adsorptive removal of arsenic(III) using plant biomass: a bioremedial approach

NASA Astrophysics Data System (ADS)

Roy, Palas; Dey, Uttiya; Chattoraj, Soumya; Mukhopadhyay, Debasis; Mondal, Naba Kumar

2017-06-01

In the present work, the possibility of using a non-conventional finely ground (250 μm) Azadirachta indica (neem) bark powder [AiBP] has been tested as a low-cost biosorbent for the removal of arsenic(III) from water. The removal of As(III) was studied by performing a series of biosorption experiments (batch and column). The biosorption behavior of As(III) for batch and column operations were examined in the concentration ranges of 50-500 µg L-1 and 500.0-2000.0 µg L-1, respectively. Under optimized batch conditions, the AiBP could remove up to 89.96 % of As(III) in water system. The artificial neural network (ANN) model was developed from batch experimental data sets which provided reasonable predictive performance ( R 2 = 0.961; 0.954) of As(III) biosorption. In batch operation, the initial As(III) concentration had the most significant impact on the biosorption process. For column operation, central composite design (CCD) was applied to investigate the influence on the breakthrough time for optimization of As(III) biosorption process and evaluation of interacting effects of different operating variables. The optimized result of CCD revealed that the AiBP was an effective and economically feasible biosorbent with maximum breakthrough time of 653.9 min, when the independent variables were retained at 2.0 g AiBP dose, 2000.0 µg L-1 initial As(III) concentrations, and 3.0 mL min-1 flow rate, at maximum desirability value of 0.969.

Data-driven Modeling of Metal-oxide Sensors with Dynamic Bayesian Networks

NASA Astrophysics Data System (ADS)

Gosangi, Rakesh; Gutierrez-Osuna, Ricardo

2011-09-01

We present a data-driven probabilistic framework to model the transient response of MOX sensors modulated with a sequence of voltage steps. Analytical models of MOX sensors are usually built based on the physico-chemical properties of the sensing materials. Although building these models provides an insight into the sensor behavior, they also require a thorough understanding of the underlying operating principles. Here we propose a data-driven approach to characterize the dynamical relationship between sensor inputs and outputs. Namely, we use dynamic Bayesian networks (DBNs), probabilistic models that represent temporal relations between a set of random variables. We identify a set of control variables that influence the sensor responses, create a graphical representation that captures the causal relations between these variables, and finally train the model with experimental data. We validated the approach on experimental data in terms of predictive accuracy and classification performance. Our results show that DBNs can accurately predict the dynamic response of MOX sensors, as well as capture the discriminatory information present in the sensor transients.

Interacting effects of age and time of day on verbal fluency performance and intraindividual variability.

PubMed

Iskandar, Sam; Murphy, Kelly J; Baird, Anne D; West, Robert; Armilio, Maria; Craik, Fergus I M; Stuss, Donald T

2016-01-01

We explored the effects of age and time of day (TOD) on verbal fluency ability with respect to performance level and intraindividual variability (IIV). Verbal fluency, which involves complex cognitive operations, was examined in 20 older (mean age = 72.8 years) and 20 younger (mean age = 24.2 years) adults with test start time alternating between morning and evening across four days. Older adults generated more words in the morning and younger adults more in the evening, corresponding with self-report peak TOD. Age by TOD interactions were also observed across fluency tasks on the number of switches among subcategory exemplars during word generation and on the IIV observed in switching behavior. Older adults exhibited greater variability in switching in the evening than in the morning, whereas younger adults showed the opposite pattern. These findings demonstrate that processes involving energization (initiating and sustaining) and attentional control may be particularly sensitive to age differences in TOD influences on cognition.

Key variables analysis of a novel continuous biodrying process for drying mixed sludge.

PubMed

Navaee-Ardeh, Shahram; Bertrand, François; Stuart, Paul R

2010-05-01

A novel continuous biodrying process has been developed whose goal is to increase the dry solids content of the sludge to economic levels rendering it suitable for a safe and economic combustion operation in a biomass boiler. The sludge drying rates are enhanced by the metabolic bioheat produced in the matrix of mixed sludge. The goal of this study was to systematically analyze the continuous biodrying reactor. By performing a variable analysis, it was found that the outlet relative humidity profile was the key variable in the biodrying reactor. The influence of different outlet relative humidity profiles was then evaluated using biodrying efficiency index. It was found that by maintaining the air outlet relative humidity profile at 85/85/96/96% in the four compartments of the reactor, the highest biodrying efficiency index can be achieved, while economic dry solids level (>45%w/w) are guaranteed. Crown Copyright 2009. Published by Elsevier Ltd. All rights reserved.

Estimating the cost of mental loading in a bimodal divided-attention task: Combining reaction time, heart-rate variability and signal-detection theory

NASA Technical Reports Server (NTRS)

Casper, Patricia A.; Kantowitz, Barry H.

1988-01-01

Multiple approaches are necessary for understanding and measuring workload. In particular, physiological systems identifiable by employing cardiac measures are related to cognitive systems. One issue of debate in measuring cardiac output is the grain of analysis used in recording and summarizing data. Various experiments are reviewed, the majority of which were directed at supporting or contradicting Lacey's intake-rejection hypothesis. Two of the experiments observed heart rate in operational environments and found virtually no changes associated with mental load. The major problems facing researchers using heart rate variability, or sinus arrhthmia, as a dependent measure have been associated with valid and sensitive scoring and preventing contamination of observed results by influences unrelated to cognition. Spectral analysis of heart rate variability offers two useful procedures: analysis from the time domain and analysis from the frequency domain. Most recently, data have been collected in a divided attention experiment, the performance measures and cardiac measures of which are detailed.

Reinforcement and Induction of Operant Variability

ERIC Educational Resources Information Center

Neuringer, Allen

2012-01-01

The target paper by Barba (2012) raises issues that were the focus of the author's first two publications on operant variability. The author will describe the main findings in those papers and then discuss Barba's specific arguments. Barba has argued against the operant nature of variability. (Contains 2 figures.)

How does complex terrain influence responses of carbon and water cycle processes to climate variability and climate change? (Invited)

NASA Astrophysics Data System (ADS)

Bond, B. J.; Peterson, K.; McKane, R.; Lajtha, K.; Quandt, D. J.; Allen, S. T.; Sell, S.; Daly, C.; Harmon, M. E.; Johnson, S. L.; Spies, T.; Sollins, P.; Abdelnour, A. G.; Stieglitz, M.

2010-12-01

We are pursuing the ambitious goal of understanding how complex terrain influences the responses of carbon and water cycle processes to climate variability and climate change. Our studies take place in H.J. Andrews Experimental Forest, an LTER (Long Term Ecological Research) site situated in Oregon’s central-western Cascade Range. Decades of long-term measurements and intensive research have revealed influences of topography on vegetation patterns, disturbance history, and hydrology. More recent research has shown surprising interactions between microclimates and synoptic weather patterns due to cold air drainage and pooling in mountain valleys. Using these data and insights, in addition to a recent LiDAR (Light Detection and Ranging) reconnaissance and a small sensor network, we are employing process-based models, including “SPA” (Soil-Plant-Atmosphere, developed by Mathew Williams of the University of Edinburgh), and “VELMA” (Visualizing Ecosystems for Land Management Alternatives, developed by Marc Stieglitz and colleagues of the Georgia Institute of Technology) to focus on two important features of mountainous landscapes: heterogeneity (both spatial and temporal) and connectivity (atmosphere-canopy-hillslope-stream). Our research questions include: 1) Do fine-scale spatial and temporal heterogeneity result in emergent properties at the basin scale, and if so, what are they? 2) How does connectivity across ecosystem components affect system responses to climate variability and change? Initial results show that for environmental drivers that elicit non-linear ecosystem responses on the plot scale, such as solar radiation, soil depth and soil water content, fine-scale spatial heterogeneity may produce unexpected emergent properties at larger scales. The results from such modeling experiments are necessarily a function of the supporting algorithms. However, comparisons based on models such as SPA and VELMA that operate at much different spatial scales (plots vs. hillslopes) and levels of biophysical organization (individual plants vs. aggregate plant biomass) can help us to understand how and why mountainous ecosystems may have distinctive responses to climate variability and climate change.

Environmental Management Model for Road Maintenance Operation Involving Community Participation

NASA Astrophysics Data System (ADS)

Triyono, A. R. H.; Setyawan, A.; Sobriyah; Setiono, P.

2017-07-01

Public expectations of Central Java, which is very high on demand fulfillment, especially road infrastructure as outlined in the number of complaints and community expectations tweeter, Short Mail Massage (SMS), e-mail and public reports from various media, Highways Department of Central Java province requires development model of environmental management in the implementation of a routine way by involving the community in order to fulfill the conditions of a representative, may serve road users safely and comfortably. This study used survey method with SEM analysis and SWOT with Latent Independent Variable (X), namely; Public Participation in the regulation, development, construction and supervision of road (PSM); Public behavior in the utilization of the road (PMJ) Provincial Road Service (PJP); Safety in the Provincial Road (KJP); Integrated Management System (SMT) and latent dependent variable (Y) routine maintenance of the provincial road that is integrated with the environmental management system and involve the participation of the community (MML). The result showed the implementation of routine maintenance of road conditions in Central Java province has yet to implement an environmental management by involving the community; Therefore developed environmental management model with the results of H1: Community Participation (PSM) has positive influence on the Model of Environmental Management (MML); H2: Behavior Society in Jalan Utilization (PMJ) positive effect on Model Environmental Management (MML); H3: Provincial Road Service (PJP) positive effect on Model Environmental Management (MML); H4: Safety in the Provincial Road (KJP) positive effect on Model Environmental Management (MML); H5: Integrated Management System (SMT) has positive influence on the Model of Environmental Management (MML). From the analysis obtained formulation model describing the relationship / influence of the independent variables PSM, PMJ, PJP, KJP, and SMT on the dependent variable MML as follows: MML = 0.13 + 0.07 PSM PJP PMJ + 0.09 + 0.19 + 0.48 KJP SMT + e

A nonlinear cointegration approach with applications to structural health monitoring

NASA Astrophysics Data System (ADS)

Shi, H.; Worden, K.; Cross, E. J.

2016-09-01

One major obstacle to the implementation of structural health monitoring (SHM) is the effect of operational and environmental variabilities, which may corrupt the signal of structural degradation. Recently, an approach inspired from the community of econometrics, called cointegration, has been employed to eliminate the adverse influence from operational and environmental changes and still maintain sensitivity to structural damage. However, the linear nature of cointegration may limit its application when confronting nonlinear relations between system responses. This paper proposes a nonlinear cointegration method based on Gaussian process regression (GPR); the method is constructed under the Engle-Granger framework, and tests for unit root processes are conducted both before and after the GPR is applied. The proposed approach is examined with real engineering data from the monitoring of the Z24 Bridge.

Operator Variability in Scan Positioning is a Major Component of HR-pQCT Precision Error and is Reduced by Standardized Training

PubMed Central

Bonaretti, Serena; Vilayphiou, Nicolas; Chan, Caroline Mai; Yu, Andrew; Nishiyama, Kyle; Liu, Danmei; Boutroy, Stephanie; Ghasem-Zadeh, Ali; Boyd, Steven K.; Chapurlat, Roland; McKay, Heather; Shane, Elizabeth; Bouxsein, Mary L.; Black, Dennis M.; Majumdar, Sharmila; Orwoll, Eric S.; Lang, Thomas F.; Khosla, Sundeep; Burghardt, Andrew J.

2017-01-01

Introduction HR-pQCT is increasingly used to assess bone quality, fracture risk and anti-fracture interventions. The contribution of the operator has not been adequately accounted in measurement precision. Operators acquire a 2D projection (“scout view image”) and define the region to be scanned by positioning a “reference line” on a standard anatomical landmark. In this study, we (i) evaluated the contribution of positioning variability to in vivo measurement precision, (ii) measured intra- and inter-operator positioning variability, and (iii) tested if custom training software led to superior reproducibility in new operators compared to experienced operators. Methods To evaluate the operator in vivo measurement precision we compared precision errors calculated in 64 co-registered and non-co-registered scan-rescan images. To quantify operator variability, we developed software that simulates the positioning process of the scanner’s software. Eight experienced operators positioned reference lines on scout view images designed to test intra- and inter-operator reproducibility. Finally, we developed modules for training and evaluation of reference line positioning. We enrolled 6 new operators to participate in a common training, followed by the same reproducibility experiments performed by the experienced group. Results In vivo precision errors were up to three-fold greater (Tt.BMD and Ct.Th) when variability in scan positioning was included. Inter-operator precision errors were significantly greater than short-term intra-operator precision (p<0.001). New trained operators achieved comparable intra-operator reproducibility to experienced operators, and lower inter-operator reproducibility (p<0.001). Precision errors were significantly greater for the radius than for the tibia. Conclusion Operator reference line positioning contributes significantly to in vivo measurement precision and is significantly greater for multi-operator datasets. Inter-operator variability can be significantly reduced using a systematic training platform, now available online (http://webapps.radiology.ucsf.edu/refline/). PMID:27475931

Effects of seasonal operation on the quality of water produced by public-supply wells

USGS Publications Warehouse

Bexfield, Laura M.; Jurgens, Bryant C.

2014-01-01

Seasonal variability in groundwater pumping is common in many places, but resulting effects of seasonal pumping stress on the quality of water produced by public-supply wells are not thoroughly understood. Analysis of historical water-quality samples from public-supply wells completed in deep basin-fill aquifers in Modesto, California (134 wells) and Albuquerque, New Mexico (95 wells) indicates that several wells have seasonal variability in concentrations of contaminants of concern. In Modesto, supply wells are more likely to produce younger groundwater with higher nitrate and uranium concentrations during the summer (high) pumping season than during the winter (low) pumping season. In Albuquerque, supply wells are more likely to produce older groundwater with higher arsenic concentrations during the winter pumping season than during the summer pumping season. Seasonal variability in contaminant concentrations in Modesto is influenced primarily by effects of summer pumping on vertical hydraulic gradients that drive migration of shallow groundwater through the aquifer to supply wells. Variability in Albuquerque is influenced primarily by the period of time that a supply well is idle, allowing its wellbore to act as a conduit for vertical groundwater flow and contaminant migration. However, both processes are observed in each study area. Similar findings would appear to be likely in other alluvial basins with stratified water quality and substantial vertical head gradients. Results suggest that even in aquifers dominated by old groundwater, changes to seasonal pumping patterns and/or to depth of well completion can help reduce vulnerability to selected contaminants of either natural or anthropogenic origin.

Effects of Seasonal Operation on the Quality of Water Produced by Public-Supply Wells

PubMed Central

Bexfield, Laura M; Jurgens, Bryant C

2014-01-01

Seasonal variability in groundwater pumping is common in many places, but resulting effects of seasonal pumping stress on the quality of water produced by public-supply wells are not thoroughly understood. Analysis of historical water-quality samples from public-supply wells completed in deep basin-fill aquifers in Modesto, California (134 wells) and Albuquerque, New Mexico (95 wells) indicates that several wells have seasonal variability in concentrations of contaminants of concern. In Modesto, supply wells are more likely to produce younger groundwater with higher nitrate and uranium concentrations during the summer (high) pumping season than during the winter (low) pumping season. In Albuquerque, supply wells are more likely to produce older groundwater with higher arsenic concentrations during the winter pumping season than during the summer pumping season. Seasonal variability in contaminant concentrations in Modesto is influenced primarily by effects of summer pumping on vertical hydraulic gradients that drive migration of shallow groundwater through the aquifer to supply wells. Variability in Albuquerque is influenced primarily by the period of time that a supply well is idle, allowing its wellbore to act as a conduit for vertical groundwater flow and contaminant migration. However, both processes are observed in each study area. Similar findings would appear to be likely in other alluvial basins with stratified water quality and substantial vertical head gradients. Results suggest that even in aquifers dominated by old groundwater, changes to seasonal pumping patterns and/or to depth of well completion can help reduce vulnerability to selected contaminants of either natural or anthropogenic origin. PMID:24593780

The Influence of Cognitive Reasoning Level, Cognitive Restructuring Ability, Disembedding Ability, Working Memory Capacity, and Prior Knowledge On Students' Performance On Balancing Equations by Inspection.

ERIC Educational Resources Information Center

Staver, John R.; Jacks, Tom

1988-01-01

Investigates the influence of five cognitive variables on high school students' performance on balancing chemical equations by inspection. Reports that reasoning, restructuring, and disembedding variables could be a single variable, and that working memory capacity does not influence overall performance. Results of hierarchical regression analysis…

Influence of Solar Variability on the North Atlantic / European Sector.

NASA Astrophysics Data System (ADS)

Gray, L. J.

2016-12-01

The 11year solar cycle signal in December-January-February averaged mean-sea-level pressure and Atlantic/European blocking frequency is examined using multilinear regression with indices to represent variability associated with the solar cycle, volcanic eruptions, the El Nino - Southern Oscillation (ENSO) and the Atlantic Multidecadal Oscillation (AMO). Results from a previous 11-year solar cycle signal study of the period 1870-2010 (140 years; 13 solar cycles) that suggested a 3-4 year lagged signal in SLP over the Atlantic are confirmed by analysis of a much longer reconstructed dataset for the period 1660-2010 (350 years; 32 solar cycles). Apparent discrepancies between earlier studies are resolved and stem primarily from the lagged nature of the response and differences between early- and late-winter responses. Analysis of the separate winter months provide supporting evidence for two mechanisms of influence, one operating via the atmosphere that maximises in late winter at 0-2 year lags and one via the mixd-layer ocean that maximises in early winter at 3-4 year lags. Corresponding analysis of DJF-averaged Atlantic / European blocking frequency shows a highly statistically significant signal at 1-year lag that originates promarily from the late winter response. The 11-year solar signal in DJF blocking frequency is compared with other known influences from ENSO and the AMO and found to be as large in amplitude and have a larger region of statistical significance.

Eating behavior: lessons from the real world of humans.

PubMed

de Castro, J M

2000-10-01

Food intake by normal humans has been investigated both in the laboratory and under free-living conditions in the natural environment. For measurement of real-world intake, the diet-diary technique is imperfect and tends to underestimate actual intakes but it appears to be sensitive, can detect subtle influences on eating behavior, and produces reliable and valid measures. Research studies in the real world show the multivariate richness of the natural environment, which allows investigation of the complexities of intake regulation, and even causation can be investigated. Real-world research can overcome some of the weaknesses of laboratory studies, where constraints on eating are often removed or missing, facilitatory influences on eating are often controlled or eliminated, the importance of variables can be overestimated, and important influences can be missed because of the short durations of the studies. Real-world studies have shown a wide array of physiologic, psychological, and social variables that can have potent and immediate effects on intake. Compensatory mechanisms, including some that operate with a 2- to 3-d delay, adjust for prior excesses. Heredity affects all aspect of food-intake regulation, from the determination of body size to the subtleties of the individual preferences and social proclivities and the extent to which environmental factors affect the individual. Hence, real-world research teaches valuable lessons, and much more is needed to complement laboratory studies.

Impact damage resistance of composite fuselage structure, part 2

NASA Technical Reports Server (NTRS)

Dost, Ernest F.; Finn, Scott R.; Murphy, Daniel P.; Huisken, Amy B.

1993-01-01

The strength of laminated composite materials may be significantly reduced by foreign object impact induced damage. An understanding of the damage state is required in order to predict the behavior of structure under operational loads or to optimize the structural configuration. Types of damage typically induced in laminated materials during an impact event include transverse matrix cracking, delamination, and/or fiber breakage. The details of the damage state and its influence on structural behavior depend on the location of the impact. Damage in the skin may act as a soft inclusion or affect panel stability, while damage occurring over a stiffener may include debonding of the stiffener flange from the skin. An experiment to characterize impact damage resistance of fuselage structure as a function of structural configuration and impact threat was performed. A wide range of variables associated with aircraft fuselage structure such as material type and stiffener geometry (termed, intrinsic variables) and variables related to the operating environment such as impactor mass and diameter (termed, extrinsic variables) were studied using a statistically based design-of-experiments technique. The experimental design resulted in thirty-two different 3-stiffener panels. These configured panels were impacted in various locations with a number of impactor configurations, weights, and energies. The results obtained from an examination of impacts in the skin midbay and hail simulation impacts are documented. The current discussion is a continuation of that work with a focus on nondiscrete characterization of the midbay hail simulation impacts and discrete characterization of impact damage for impacts over the stiffener.

Impact of tidal density variability on orbital and reentry predictions

NASA Astrophysics Data System (ADS)

Leonard, J. M.; Forbes, J. M.; Born, G. H.

2012-12-01

Since the first satellites entered Earth orbit in the late 1950's and early 1960's, the influences of solar and geomagnetic variability on the satellite drag environment have been studied, and parameterized in empirical density models with increasing sophistication. However, only within the past 5 years has the realization emerged that "troposphere weather" contributes significantly to the "space weather" of the thermosphere, especially during solar minimum conditions. Much of the attendant variability is attributable to upward-propagating solar tides excited by latent heating due to deep tropical convection, and solar radiation absorption primarily by water vapor and ozone in the stratosphere and mesosphere, respectively. We know that this tidal spectrum significantly modifies the orbital (>200 km) and reentry (60-150 km) drag environments, and that these tidal components induce longitude variability not yet emulated in empirical density models. Yet, current requirements for improvements in orbital prediction make clear that further refinements to density models are needed. In this paper, the operational consequences of longitude-dependent tides are quantitatively assessed through a series of orbital and reentry predictions. We find that in-track prediction differences incurred by tidal effects are typically of order 200 ± 100 m for satellites in 400-km circular orbits and 15 ± 10 km for satellites in 200-km circular orbits for a 24-hour prediction. For an initial 200-km circular orbit, surface impact differences of order 15° ± 15° latitude are incurred. For operational problems with similar accuracy needs, a density model that includes a climatological representation of longitude-dependent tides should significantly reduce errors due to this source.

Does Day Length Affect Winter Bird Distribution? Testing the Role of an Elusive Variable

PubMed Central

Carrascal, Luis M.; Santos, Tomás; Tellería, José L.

2012-01-01

Differences in day length may act as a critical factor in bird biology by introducing time constraints in energy acquisition during winter. Thus, differences in day length might operate as a main determinant of bird abundance along latitudinal gradients. This work examines the influence of day length on the abundance of wintering crested tits (Lophophanes cristatus) in 26 localities of Spanish juniper (Juniperus thurifera) dwarf woodlands (average height of 5 m) located along a latitudinal gradient in the Spanish highlands, while controlling for the influence of food availability, minimum night temperature, habitat structure and landscape characteristics. Top regression models in the AIC framework explained 56% of variance in bird numbers. All models incorporated day length as the variable with the highest magnitude effect. Food availability also played an important role, although only the crop of ripe juniper fruits, but not arthropods, positively affected crested tit abundance. Differences in vegetation structure across localities had also a strong positive effect (average tree height and juniper tree density). Geographical variation in night temperature had no influence on crested tit distribution, despite the low winter temperatures reached in these dwarf forests. This paper demonstrates for the first time that winter bird abundance increases with day length after controlling for the effect of other environmental variables. Winter average difference in day length was only 10.5 minutes per day along the 1°47′ latitudinal interval (190 km) included in this study. This amount of time, which reaches 13.5 h accumulated throughout the winter season, appears to be large enough to affect the long-term energy budget of small passerines during winter and to shape the distribution of winter bird abundance under restrictive environmental conditions. PMID:22393442

Determining the influence and effects of manufacturing variables on sulfur dioxide cells

NASA Technical Reports Server (NTRS)

Zajac, W. V.; Thomas, M. A.; Barnes, J. A.; Bis, R., F.; Davis, P. B.; Debold, F. C.; Gemmill, G. W.; Kowalchik, L. A.

1986-01-01

A survey of the Li/SO2 manufacturing community was conducted to determine where variability exists in processing. The upper and lower limits of these processing variables might, by themselves or by interacting with other variables, influence safety, performance, and reliability. A number of important variables were identified and a comprehensive design experiment is being proposed to make the proper determinations.

Disentangling the effects of genetic, prenatal and parenting influences on children's cortisol variability.

PubMed

Marceau, Kristine; Ram, Nilam; Neiderhiser, Jenae M; Laurent, Heidemarie K; Shaw, Daniel S; Fisher, Phil; Natsuaki, Misaki N; Leve, Leslie D

2013-11-01

Developmental plasticity models hypothesize the role of genetic and prenatal environmental influences on the development of the hypothalamic-pituitary-adrenal (HPA) axis and highlight that genes and the prenatal environment may moderate early postnatal environmental influences on HPA functioning. This article examines the interplay of genetic, prenatal and parenting influences across the first 4.5 years of life on a novel index of children's cortisol variability. Repeated measures data were obtained from 134 adoption-linked families, adopted children and both their adoptive parents and birth mothers, who participated in a longitudinal, prospective US domestic adoption study. Genetic and prenatal influences moderated associations between inconsistency in overreactive parenting from child age 9 months to 4.5 years and children's cortisol variability at 4.5 years differently for mothers and fathers. Among children whose birth mothers had high morning cortisol, adoptive fathers' inconsistent overreactive parenting predicted higher cortisol variability, whereas among children with low birth mother morning cortisol adoptive fathers' inconsistent overreactive parenting predicted lower cortisol variability. Among children who experienced high levels of prenatal risk, adoptive mothers' inconsistent overreactive parenting predicted lower cortisol variability and adoptive fathers' inconsistent overreactive parenting predicted higher cortisol variability, whereas among children who experienced low levels of prenatal risk there were no associations between inconsistent overreactive parenting and children's cortisol variability. Findings supported developmental plasticity models and uncovered novel developmental, gene × environment and prenatal × environment influences on children's cortisol functioning.

Determining the factors affecting the distribution of Muscari latifolium, an endemic plant of Turkey, and a mapping species distribution model.

PubMed

Yilmaz, Hatice; Yilmaz, Osman Yalçın; Akyüz, Yaşar Feyza

2017-02-01

Species distribution modeling was used to determine factors among the large predictor candidate data set that affect the distribution of Muscari latifolium , an endemic bulbous plant species of Turkey, to quantify the relative importance of each factor and make a potential spatial distribution map of M. latifolium . Models were built using the Boosted Regression Trees method based on 35 presence and 70 absence records obtained through field sampling in the Gönen Dam watershed area of the Kazdağı Mountains in West Anatolia. Large candidate variables of monthly and seasonal climate, fine-scale land surface, and geologic and biotic variables were simplified using a BRT simplifying procedure. Analyses performed on these resources, direct and indirect variables showed that there were 14 main factors that influence the species' distribution. Five of the 14 most important variables influencing the distribution of the species are bedrock type, Quercus cerris density, precipitation during the wettest month, Pinus nigra density, and northness. These variables account for approximately 60% of the relative importance for determining the distribution of the species. Prediction performance was assessed by 10 random subsample data sets and gave a maximum the area under a receiver operating characteristic curve (AUC) value of 0.93 and an average AUC value of 0.8. This study provides a significant contribution to the knowledge of the habitat requirements and ecological characteristics of this species. The distribution of this species is explained by a combination of biotic and abiotic factors. Hence, using biotic interaction and fine-scale land surface variables in species distribution models improved the accuracy and precision of the model. The knowledge of the relationships between distribution patterns and environmental factors and biotic interaction of M. latifolium can help develop a management and conservation strategy for this species.

Comparative study of air-conditioning energy use of four office buildings in China and USA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou, Xin; Yan, Da; An, Jingjing

Energy use in buildings has great variability. In order to design and operate low energy buildings as well as to establish building energy codes and standards and effective energy policy, it is crucial to understand and quantify key factors influencing building energy performance. Here, this study investigates air-conditioning (AC) energy use of four office buildings in four locations: Beijing, Taiwan, Hong Kong, and Berkeley. Building simulation was employed to quantify the influences of key factors, including climate, building envelope and occupant behavior. Through simulation of various combinations of the three influencing elements, it is found that climate can lead tomore » AC cooling consumption differences by almost two times, while occupant behavior resulted in the greatest differences (of up to three times) in AC cooling consumption. The influence of occupant behavior on AC energy consumption is not homogeneous. Under similar climates, when the occupant behavior in the building differed, the optimized building envelope design also differed. In conclusion, the optimal building envelope should be determined according to the climate as well as the occupants who use the building.« less

Comparative study of air-conditioning energy use of four office buildings in China and USA

DOE PAGES

Zhou, Xin; Yan, Da; An, Jingjing; ...

2018-04-05

Energy use in buildings has great variability. In order to design and operate low energy buildings as well as to establish building energy codes and standards and effective energy policy, it is crucial to understand and quantify key factors influencing building energy performance. Here, this study investigates air-conditioning (AC) energy use of four office buildings in four locations: Beijing, Taiwan, Hong Kong, and Berkeley. Building simulation was employed to quantify the influences of key factors, including climate, building envelope and occupant behavior. Through simulation of various combinations of the three influencing elements, it is found that climate can lead tomore » AC cooling consumption differences by almost two times, while occupant behavior resulted in the greatest differences (of up to three times) in AC cooling consumption. The influence of occupant behavior on AC energy consumption is not homogeneous. Under similar climates, when the occupant behavior in the building differed, the optimized building envelope design also differed. In conclusion, the optimal building envelope should be determined according to the climate as well as the occupants who use the building.« less

Transcranial Magnetic Stimulation: Decomposing the Processes Underlying Action Preparation.

PubMed

Bestmann, Sven; Duque, Julie

2016-08-01

Preparing actions requires the operation of several cognitive control processes that influence the state of the motor system to ensure that the appropriate behavior is ultimately selected and executed. For example, some form of competition resolution ensures that the right action is chosen among alternatives, often in the presence of conflict; at the same time, impulse control ought to be deployed to prevent premature responses. Here we review how state-changes in the human motor system during action preparation can be studied through motor-evoked potentials (MEPs) elicited by transcranial magnetic stimulation over the contralateral primary motor cortex (M1). We discuss how the physiological fingerprints afforded by MEPs have helped to decompose some of the dynamic and effector-specific influences on the motor system during action preparation. We focus on competition resolution, conflict and impulse control, as well as on the influence of higher cognitive decision-related variables. The selected examples demonstrate the usefulness of MEPs as physiological readouts for decomposing the influence of distinct, but often overlapping, control processes on the human motor system during action preparation. © The Author(s) 2015.

A Fully Associative, Non-Linear Kinematic, Unified Viscoplastic Model for Titanium Based Matrices

NASA Technical Reports Server (NTRS)

Arnold, S. M.; Saleeb, A. F.; Castelli, M. G.

1994-01-01

Specific forms for both the Gibb's and complementary dissipation potentials are chosen such that a complete (i.e., fully associative) potential based multiaxial unified viscoplastic model is obtained. This model possesses one tensorial internal state variable that is associated with dislocation substructure, with an evolutionary law that has nonlinear kinematic hardening and both thermal and strain induced recovery mechanisms. A unique aspect of the present model is the inclusion of non-linear hardening through the use of a compliance operator, derived from the Gibb's potential, in the evolution law for the back stress. This non-linear tensorial operator is significant in that it allows both the flow and evolutionary laws to be fully associative (and therefore easily integrated) and greatly influences the multiaxial response under non-proportional loading paths. In addition to this nonlinear compliance operator, a new consistent, potential preserving, internal strain unloading criterion has been introduced to prevent abnormalities in the predicted stress-strain curves, which are present with nonlinear hardening formulations, during unloading and reversed loading of the external variables. Specification of an experimental program for the complete determination of the material functions and parameters for characterizing a metallic matrix, e.g., TIMETAL 21S, is given. The experiments utilized are tensile, creep, and step creep tests. Finally, a comparison of this model and a commonly used Bodner-Partom model is made on the basis of predictive accuracy and numerical efficiency.

Variable Order and Distributed Order Fractional Operators

NASA Technical Reports Server (NTRS)

Lorenzo, Carl F.; Hartley, Tom T.

2002-01-01

Many physical processes appear to exhibit fractional order behavior that may vary with time or space. The continuum of order in the fractional calculus allows the order of the fractional operator to be considered as a variable. This paper develops the concept of variable and distributed order fractional operators. Definitions based on the Riemann-Liouville definitions are introduced and behavior of the operators is studied. Several time domain definitions that assign different arguments to the order q in the Riemann-Liouville definition are introduced. For each of these definitions various characteristics are determined. These include: time invariance of the operator, operator initialization, physical realization, linearity, operational transforms. and memory characteristics of the defining kernels. A measure (m2) for memory retentiveness of the order history is introduced. A generalized linear argument for the order q allows the concept of "tailored" variable order fractional operators whose a, memory may be chosen for a particular application. Memory retentiveness (m2) and order dynamic behavior are investigated and applications are shown. The concept of distributed order operators where the order of the time based operator depends on an additional independent (spatial) variable is also forwarded. Several definitions and their Laplace transforms are developed, analysis methods with these operators are demonstrated, and examples shown. Finally operators of multivariable and distributed order are defined in their various applications are outlined.

Functional analysis and intervention for perseverative verbal behaviour of an older adult with traumatic brain injury.

PubMed

Quearry, Amy Garcia; Lundervold, Duane A

2016-01-01

A functional analysis of behaviour was conducted to determine the controlling variables related to the perseverative verbal behaviour (PBV) of a 60-year-old female with a long-standing traumatic brain injury receiving educational assistance. Functional analyses (FA) of antecedent and consequent conditions related to PCB were conducted to determine controlling influence of: (a) content of verbal interaction and, (b) social reinforcement. After isolating the controlling variables, the functioned-based intervention was implemented in 60 minute tutoring sessions. A reversal condition was used to demonstrate experimental control of the behavior during tutoring sessions. PVB which occurred in the context of tutoring for an undergraduate course significantly interfered with the delivery of instruction. Multiple replications of the functional relation between social reinforcement and PVB duration was demonstrated using an A-B-A-B reversal design during functional analysis and tutoring conditions. PVB markedly declined, but did not extinguish over the course of weekly tutoring (extinction) sessions, most likely due to 'bootleg reinforcement' occurring in other situations. Results indicate that perseverative verbal behaviour following closed head injury may be strongly influenced by the social contingencies operating in various contexts and is amenable to applied behaviour analysis interventions.

Discoveries about Tropospheric Ozone Pollution from Satellite and Soundings

NASA Technical Reports Server (NTRS)

Thompson, Anne M.

2004-01-01

We have been producing near-red time tropospheric ozone satellite maps from the TOMS (Total Ozone Mapping Spectrometer) sensor since 1997. Maps for 1996-2000 for the operational Earth-Probe instrument are at:. Pollution in the tropics is influenced by biomass burning and by transport patterns that favor recirculation and in other cases reflect climate variability like the El-Nino-Southern Oscillation [Thompson et al., 2001]. The satellite view of chemical-dynamical interactions in tropospheric ozone is not adequate to capture vertical gradients in pollution. Thus, in 1998, NASA's Goddard Space Flight Center and a team of international sponsors established the SHADOZ (Southern Hemisphere ADditional OZonesondes) project to address the gap in tropical ozone soundings. SHADOZ augments launches and provides a public archive of ozonesonde data from twelve tropical stations at http://croc.gsfc.nasa.gov/shadoz. Further insights into the role of chemical and dynamical influences have emerged from the first 4-5 years of SHADOZ data (more than 2000 ozone profiles). Highly variable tropospheric ozone and a zonal wave-one pattern in tropospheric ozone suggest that dynamics is as important as pollution in determining tropical ozone distributions.

Biotic and abiotic variables influencing plant litter breakdown in streams: a global study.

PubMed

Boyero, Luz; Pearson, Richard G; Hui, Cang; Gessner, Mark O; Pérez, Javier; Alexandrou, Markos A; Graça, Manuel A S; Cardinale, Bradley J; Albariño, Ricardo J; Arunachalam, Muthukumarasamy; Barmuta, Leon A; Boulton, Andrew J; Bruder, Andreas; Callisto, Marcos; Chauvet, Eric; Death, Russell G; Dudgeon, David; Encalada, Andrea C; Ferreira, Verónica; Figueroa, Ricardo; Flecker, Alexander S; Gonçalves, José F; Helson, Julie; Iwata, Tomoya; Jinggut, Tajang; Mathooko, Jude; Mathuriau, Catherine; M'Erimba, Charles; Moretti, Marcelo S; Pringle, Catherine M; Ramírez, Alonso; Ratnarajah, Lavenia; Rincon, José; Yule, Catherine M

2016-04-27

Plant litter breakdown is a key ecological process in terrestrial and freshwater ecosystems. Streams and rivers, in particular, contribute substantially to global carbon fluxes. However, there is little information available on the relative roles of different drivers of plant litter breakdown in fresh waters, particularly at large scales. We present a global-scale study of litter breakdown in streams to compare the roles of biotic, climatic and other environmental factors on breakdown rates. We conducted an experiment in 24 streams encompassing latitudes from 47.8° N to 42.8° S, using litter mixtures of local species differing in quality and phylogenetic diversity (PD), and alder (Alnus glutinosa) to control for variation in litter traits. Our models revealed that breakdown of alder was driven by climate, with some influence of pH, whereas variation in breakdown of litter mixtures was explained mainly by litter quality and PD. Effects of litter quality and PD and stream pH were more positive at higher temperatures, indicating that different mechanisms may operate at different latitudes. These results reflect global variability caused by multiple factors, but unexplained variance points to the need for expanded global-scale comparisons. © 2016 The Author(s).

Dehydroepiandrosterone and dehydroepiandrosterone sulfate: anabolic, neuroprotective, and neuroexcitatory properties in military men.

PubMed

Taylor, Marcus K

2013-01-01

Evidence links dehydroepiandrosterone (DHEA) and dehydroepiandrosterone sulfate (DHEAS) to crucial military health issues, including operational stress, resilience, and traumatic brain injury. This study evaluated the anabolic, neuroprotective, and neuroexcitatory properties of DHEA(S) in healthy military men. A salivary sample was obtained from 42 men and assayed for DHEA(S), testosterone, nerve growth factor (NGF; which supports nerve cell proliferation), and salivary alpha amylase (sAA; a proxy of sympathetic nervous system function). Separate regression analyses were conducted with DHEA and DHEAS as independent variables, and testosterone, NGF, and sAA as dependent variables, respectively. The models explained 23.4% of variance in testosterone (p < 0.01), 17.2% of variance in NGF (p < 0.01), and 7.4% of variance in sAA (p = 0.09). Standardized beta coefficients revealed that DHEA independently influenced testosterone (beta = 0.40, p < 0.01), whereas DHEAS independently influenced NGF (beta = 0.48, p < 0.01) and sAA (beta = 0.36, p < 0.05). DHEA demonstrated anabolic properties, whereas DHEAS demonstrated neuroprotective and neuroexcitatory properties in military men. This area of study has broad implications for stress inoculation, traumatic brain injury rehabilitation, and regenerative medicine in military personnel.

Biotic and abiotic variables influencing plant litter breakdown in streams: a global study

PubMed Central

Pearson, Richard G.; Hui, Cang; Gessner, Mark O.; Pérez, Javier; Alexandrou, Markos A.; Graça, Manuel A. S.; Cardinale, Bradley J.; Albariño, Ricardo J.; Arunachalam, Muthukumarasamy; Barmuta, Leon A.; Boulton, Andrew J.; Bruder, Andreas; Callisto, Marcos; Chauvet, Eric; Death, Russell G.; Dudgeon, David; Encalada, Andrea C.; Ferreira, Verónica; Figueroa, Ricardo; Flecker, Alexander S.; Gonçalves, José F.; Helson, Julie; Iwata, Tomoya; Jinggut, Tajang; Mathooko, Jude; Mathuriau, Catherine; M'Erimba, Charles; Moretti, Marcelo S.; Pringle, Catherine M.; Ramírez, Alonso; Ratnarajah, Lavenia; Rincon, José; Yule, Catherine M.

2016-01-01

Plant litter breakdown is a key ecological process in terrestrial and freshwater ecosystems. Streams and rivers, in particular, contribute substantially to global carbon fluxes. However, there is little information available on the relative roles of different drivers of plant litter breakdown in fresh waters, particularly at large scales. We present a global-scale study of litter breakdown in streams to compare the roles of biotic, climatic and other environmental factors on breakdown rates. We conducted an experiment in 24 streams encompassing latitudes from 47.8° N to 42.8° S, using litter mixtures of local species differing in quality and phylogenetic diversity (PD), and alder (Alnus glutinosa) to control for variation in litter traits. Our models revealed that breakdown of alder was driven by climate, with some influence of pH, whereas variation in breakdown of litter mixtures was explained mainly by litter quality and PD. Effects of litter quality and PD and stream pH were more positive at higher temperatures, indicating that different mechanisms may operate at different latitudes. These results reflect global variability caused by multiple factors, but unexplained variance points to the need for expanded global-scale comparisons. PMID:27122551

Influence of the South-to-North Water Transfer and the Yangtze River Mitigation Projects on the water quality of Han River, China

NASA Astrophysics Data System (ADS)

Liu, W.; Kuo, Y. M.

2016-12-01

The Middle Route of China's South-to-North Water Transfer (MSNW) and Yangtze-Han River Water Diversion (YHWD) Projects have been operated since 2014, which may deteriorate water quality in Han River. The 11 water sampling sites distributed from the middle and down streams of Han River watershed were monitored monthly between July 2014 and December 2015. Factor analysis and cluster analysis were applied to investigate the major pollution types and main variables influencing water quality in Han River. The factor analysis distinguishes three main pollution types (agricultural nonpoint source, organic, and phosphorus point source pollution) affecting water quality of Han River. Cluster analysis classified all sampling sites into four groups and determined their pollution source for both Dry and Wet seasons. The sites located at central city receive point source pollution in both seasons. The water quality in downstream Han River (excluding central city sites) was influenced by nonpoint source pollution from Jianghan Plain. Variations of water qualities are associated with hydrological conditions varied from operations of engineering projects and seasonal variability especially in Dry season. Good water quality as Class III mainly occurred when flow rate is greater than 800 cms in Dry season. The low average flow rate below 583 cms will degrade water quality as Class V at almost all sites. Elevating the flow rate discharged from MSNW and YHWD Projects to Han River can avoid degrading water quality especially in low flow conditions and may decrease the probability of algal bloom occurrence in Han River. Increasing the flow rate from 400 cms to 700 cms in main Han River can obviously improve the water quality of Han River. The investigation of relationships between water quality and flow rate in both projects can provide management strategies of water quality for various flow conditions.

A practical tool for modeling biospecimen user fees.

PubMed

Matzke, Lise; Dee, Simon; Bartlett, John; Damaraju, Sambasivarao; Graham, Kathryn; Johnston, Randal; Mes-Masson, Anne-Marie; Murphy, Leigh; Shepherd, Lois; Schacter, Brent; Watson, Peter H

2014-08-01

The question of how best to attribute the unit costs of the annotated biospecimen product that is provided to a research user is a common issue for many biobanks. Some of the factors influencing user fees are capital and operating costs, internal and external demand and market competition, and moral standards that dictate that fees must have an ethical basis. It is therefore important to establish a transparent and accurate costing tool that can be utilized by biobanks and aid them in establishing biospecimen user fees. To address this issue, we built a biospecimen user fee calculator tool, accessible online at www.biobanking.org . The tool was built to allow input of: i) annual operating and capital costs; ii) costs categorized by the major core biobanking operations; iii) specimen products requested by a biobank user; and iv) services provided by the biobank beyond core operations (e.g., histology, tissue micro-array); as well as v) several user defined variables to allow the calculator to be adapted to different biobank operational designs. To establish default values for variables within the calculator, we first surveyed the members of the Canadian Tumour Repository Network (CTRNet) management committee. We then enrolled four different participants from CTRNet biobanks to test the hypothesis that the calculator tool could change approaches to user fees. Participants were first asked to estimate user fee pricing for three hypothetical user scenarios based on their biobanking experience (estimated pricing) and then to calculate fees for the same scenarios using the calculator tool (calculated pricing). Results demonstrated significant variation in estimated pricing that was reduced by calculated pricing, and that higher user fees are consistently derived when using the calculator. We conclude that adoption of this online calculator for user fee determination is an important first step towards harmonization and realistic user fees.

The effect of smoking on surgical outcomes in ventral hernia repair: a propensity score matched analysis of the National Surgical Quality Improvement Program data.

PubMed

Borad, N P; Merchant, A M

2017-12-01

Although studies have implicated smoking as a positive predictor of post-operative outcomes in inguinal hernia repair, its impact on ventral hernia repair (VHR) is not as clear. This study aims to fill this gap by investigating the impact of smoking on developing adverse 30-day post-operative outcomes in VHR. Patients undergoing VHR between 2005 and 2014 were extracted from the American College of Surgeons National Surgical Quality Improvement Program database. Patients were stratified by smoking status and compared for significant differences in baseline characteristics. Logistic regression modeled the impact of smoking on the primary outcome variable of 30-day mortality and the secondary outcome variables of 30-day overall, cardiac, respiratory, or wound morbidity. To evaluate the influence of smoking in comparable groups undergoing VHR, a propensity score matched analysis was performed. Out of 169,458 patients identified, 32,973 (19.5%) were classified as current smokers. Smokers and non/ex-smokers differed significantly in multiple pre-operative baseline characteristics. Unmatched univariate analyses revealed smoking status as a positive predictor of every post-operative outcome. These findings were validated with propensity score matching analyses, which found current smokers have an increased likelihood of 30-day mortality (OR 1.42), overall morbidity (OR 1.39), wound (OR 1.40), respiratory (OR 1.14), or cardiac morbidity (OR 1.88) compared to non/ex-smokers (p < 0.05 for all). Smoking is a modifiable risk factor with a detrimental impact on outcomes in patients undergoing ventral hernia repair. Delaying VHR and promoting smoking cessation prior to surgery may help reduce the odds of adverse 30-day post-operative outcomes.

Duration of hospital stay following orthognathic surgery at the jordan university hospital.

PubMed

Jarab, Fadi; Omar, Esam; Bhayat, Ahmed; Mansuri, Samir; Ahmed, Sami

2012-09-01

Major oral and maxillofacial surgery procedures have been routinely performed on an inpatient basis in order to manage both, the recovery from anesthesia and any unpredictable morbidity that may be associated with the surgery. The use of inpatient beds is extremely expensive and if the surgical procedures could be done on an outpatient setting, it would reduce the costs and the need for inpatient care. The aim was to determine the length of hospital stay (LHS) and the factors which influence the LHS following orthognathic surgery at the Jordan University Hospital over 5 years (2005-2009). This was a retrospective record review of patients who underwent orthognathic surgery at Jordan University Hospital between 2005 and 2009. The variables were recorded on a data capture form which was adapted and developed from previous studies. Descriptive and analytical statistical methods were used to correlate these variables to the LHS. Ninety two patients were included in the study and 74% of them were females. The mean age was 23.7 years and the mean LHS was 4 days. The complexity of the procedure, length of operation time, intensive care unit (ICU) stay and year of operation were significantly correlated with a positive LHS (P < 0.05). Patients' hospital stay was directly related to the complexity of the orthognathic procedure, the operation time, time spent in ICU and the year in which the operation was done. There was a significant reduction in the LHS over the progressing years and this could be due to an increase in experience and knowledge of the operators and an improvement in the hospital facilities.

Formulation development and optimization of a novel Cremophore EL-based nanoemulsion using ultrasound cavitation.

PubMed

Tang, Siah Ying; Manickam, Sivakumar; Wei, Tan Khang; Nashiru, Billa

2012-03-01

In the present study, response surface methodology (RSM) based on central composite design (CCD) was employed to investigate the influence of main emulsion composition variables, namely drug loading, oil content, emulsifier content as well as the effect of the ultrasonic operating parameters such as pre-mixing time, ultrasonic amplitude, and irradiation time on the properties of aspirin-loaded nanoemulsions. The two main emulsion properties studied as response variables were: mean droplet size and polydispersity index. The ultimate goal of the present work was to determine the optimum level of the six independent variables in which an optimal aspirin nanoemulsion with desirable properties could be produced. The response surface analysis results clearly showed that the variability of two responses could be depicted as a linear function of the content of main emulsion compositions and ultrasonic processing variables. In the present investigation, it is evidently shown that ultrasound cavitation is a powerful yet promising approach in the controlled production of aspirin nanoemulsions with smaller average droplet size in a range of 200-300 nm and with a polydispersity index (PDI) of about 0.30. This study proved that the use of low frequency ultrasound is of considerable importance in the controlled production of pharmaceutical nanoemulsions in the drug delivery system. Copyright © 2011 Elsevier B.V. All rights reserved.

Operational Assessment of Apollo Lunar Surface Extravehicular Activity

NASA Technical Reports Server (NTRS)

Miller, Matthew James; Claybrook, Austin; Greenlund, Suraj; Marquez, Jessica J.; Feigh, Karen M.

2017-01-01

Quantifying the operational variability of extravehicular activity (EVA) execution is critical to help design and build future support systems to enable astronauts to monitor and manage operations in deep-space, where ground support operators will no longer be able to react instantly and manage execution deviations due to the significant communication latency. This study quantifies the operational variability exhibited during Apollo 14-17 lunar surface EVA operations to better understand the challenges and natural tendencies of timeline execution and life support system performance involved in surface operations. Each EVA (11 in total) is individually summarized as well as aggregated to provide descriptive trends exhibited throughout the Apollo missions. This work extends previous EVA task analyses by calculating deviations between planned and as-performed timelines as well as examining metabolic rate and consumables usage throughout the execution of each EVA. The intent of this work is to convey the natural variability of EVA operations and to provide operational context for coping with the variability inherent to EVA execution as a means to support future concepts of operations.

A Framework for Assessing Operational Madden–Julian Oscillation Forecasts: A CLIVAR MJO Working Group Project

DOE PAGES

Gottschalck, J.; Wheeler, M.; Weickmann, K.; ...

2010-09-01

The U.S. Climate Variability and Predictability (CLIVAR) MJO Working Group (MJOWG) has taken steps to promote the adoption of a uniform diagnostic and set of skill metrics for analyzing and assessing dynamical forecasts of the MJO. Here we describe the framework and initial implementation of the approach using real-time forecast data from multiple operational numerical weather prediction (NWP) centers. The objectives of this activity are to provide a means to i) quantitatively compare skill of MJO forecasts across operational centers, ii) measure gains in forecast skill over time by a given center and the community as a whole, and iii)more » facilitate the development of a multimodel forecast of the MJO. The MJO diagnostic is based on extensive deliberations among the MJOWG in conjunction with input from a number of operational centers and makes use of the MJO index of Wheeler and Hendon. This forecast activity has been endorsed by the Working Group on Numerical Experimentation (WGNE), the international body that fosters the development of atmospheric models for NWP and climate studies. The Climate Prediction Center (CPC) within the National Centers for Environmental Prediction (NCEP) is hosting the acquisition of the forecast data, application of the MJO diagnostic, and real-time display of the standardized forecasts. The activity has contributed to the production of 1–2-week operational outlooks at NCEP and activities at other centers. Further enhancements of the diagnostic's implementation, including more extensive analysis, comparison, illustration, and verification of the contributions from the participating centers, will increase the usefulness and application of these forecasts and potentially lead to more skillful predictions of the MJO and indirectly extratropical and other weather variability (e.g., tropical cyclones) influenced by the MJO. The purpose of this article is to inform the larger scientific and operational forecast communities of the MJOWG forecast effort and invite participation from additional operational centers.« less

Heart Rate Variability: New Perspectives on Physiological Mechanisms, Assessment of Self-regulatory Capacity, and Health risk

PubMed Central

Shaffer, Fred

2015-01-01

Heart rate variability, the change in the time intervals between adjacent heartbeats, is an emergent property of interdependent regulatory systems that operates on different time scales to adapt to environmental and psychological challenges. This article briefly reviews neural regulation of the heart and offers some new perspectives on mechanisms underlying the very low frequency rhythm of heart rate variability. Interpretation of heart rate variability rhythms in the context of health risk and physiological and psychological self-regulatory capacity assessment is discussed. The cardiovascular regulatory centers in the spinal cord and medulla integrate inputs from higher brain centers with afferent cardiovascular system inputs to adjust heart rate and blood pressure via sympathetic and parasympathetic efferent pathways. We also discuss the intrinsic cardiac nervous system and the heart-brain connection pathways, through which afferent information can influence activity in the subcortical, frontocortical, and motor cortex areas. In addition, the use of real-time HRV feedback to increase self-regulatory capacity is reviewed. We conclude that the heart's rhythms are characterized by both complexity and stability over longer time scales that reflect both physiological and psychological functional status of these internal self-regulatory systems. PMID:25694852

Heart Rate Variability: New Perspectives on Physiological Mechanisms, Assessment of Self-regulatory Capacity, and Health risk.

PubMed

McCraty, Rollin; Shaffer, Fred

2015-01-01

Heart rate variability, the change in the time intervals between adjacent heartbeats, is an emergent property of interdependent regulatory systems that operates on different time scales to adapt to environmental and psychological challenges. This article briefly reviews neural regulation of the heart and offers some new perspectives on mechanisms underlying the very low frequency rhythm of heart rate variability. Interpretation of heart rate variability rhythms in the context of health risk and physiological and psychological self-regulatory capacity assessment is discussed. The cardiovascular regulatory centers in the spinal cord and medulla integrate inputs from higher brain centers with afferent cardiovascular system inputs to adjust heart rate and blood pressure via sympathetic and parasympathetic efferent pathways. We also discuss the intrinsic cardiac nervous system and the heart-brain connection pathways, through which afferent information can influence activity in the subcortical, frontocortical, and motor cortex areas. In addition, the use of real-time HRV feedback to increase self-regulatory capacity is reviewed. We conclude that the heart's rhythms are characterized by both complexity and stability over longer time scales that reflect both physiological and psychological functional status of these internal self-regulatory systems.

Operating Comfort Prediction Model of Human-Machine Interface Layout for Cabin Based on GEP.

PubMed

Deng, Li; Wang, Guohua; Chen, Bo

2015-01-01

In view of the evaluation and decision-making problem of human-machine interface layout design for cabin, the operating comfort prediction model is proposed based on GEP (Gene Expression Programming), using operating comfort to evaluate layout scheme. Through joint angles to describe operating posture of upper limb, the joint angles are taken as independent variables to establish the comfort model of operating posture. Factor analysis is adopted to decrease the variable dimension; the model's input variables are reduced from 16 joint angles to 4 comfort impact factors, and the output variable is operating comfort score. The Chinese virtual human body model is built by CATIA software, which will be used to simulate and evaluate the operators' operating comfort. With 22 groups of evaluation data as training sample and validation sample, GEP algorithm is used to obtain the best fitting function between the joint angles and the operating comfort; then, operating comfort can be predicted quantitatively. The operating comfort prediction result of human-machine interface layout of driller control room shows that operating comfort prediction model based on GEP is fast and efficient, it has good prediction effect, and it can improve the design efficiency.

Operating Comfort Prediction Model of Human-Machine Interface Layout for Cabin Based on GEP

PubMed Central

Wang, Guohua; Chen, Bo

2015-01-01

In view of the evaluation and decision-making problem of human-machine interface layout design for cabin, the operating comfort prediction model is proposed based on GEP (Gene Expression Programming), using operating comfort to evaluate layout scheme. Through joint angles to describe operating posture of upper limb, the joint angles are taken as independent variables to establish the comfort model of operating posture. Factor analysis is adopted to decrease the variable dimension; the model's input variables are reduced from 16 joint angles to 4 comfort impact factors, and the output variable is operating comfort score. The Chinese virtual human body model is built by CATIA software, which will be used to simulate and evaluate the operators' operating comfort. With 22 groups of evaluation data as training sample and validation sample, GEP algorithm is used to obtain the best fitting function between the joint angles and the operating comfort; then, operating comfort can be predicted quantitatively. The operating comfort prediction result of human-machine interface layout of driller control room shows that operating comfort prediction model based on GEP is fast and efficient, it has good prediction effect, and it can improve the design efficiency. PMID:26448740

Frequency-dependent ultrasound-induced transformation in E. coli.

PubMed

Deeks, Jeremy; Windmill, James; Agbeze-Onuma, Maduka; Kalin, Robert M; Argondizza, Peter; Knapp, Charles W

2014-12-01

Ultrasound-enhanced gene transfer (UEGT) is continuing to gain interest across many disciplines; however, very few studies investigate UEGT efficiency across a range of frequencies. Using a variable frequency generator, UEGT was tested in E. coli at six ultrasonic frequencies. Results indicate frequency can significantly influence UEGT efficiency positively and negatively. A frequency of 61 kHz improved UEGT efficiency by ~70 % higher, but 99 kHz impeded UEGT to an extent worse than no ultrasound exposure. The other four frequencies (26, 133, 174, and 190 kHz) enhanced transformation compared to no ultrasound, but efficiencies did not vary. The influence of frequency on UEGT efficiency was observed across a range of operating frequencies. It is plausible that frequency-dependent dynamics of mechanical and chemical energies released during cavitational-bubble collapse (CBC) are responsible for observed UEGT efficiencies.

Operant Variability: A Conceptual Analysis

ERIC Educational Resources Information Center

Barba, Lourenco de Souza

2012-01-01

Some researchers claim that variability is an operant dimension of behavior. The present paper reviews the concept of operant behavior and emphasizes that differentiation is the behavioral process that demonstrates an operant relation. Differentiation is conceived as change in the overlap between two probability distributions: the distribution of…

The exploration of effects of Chinese cultural values on the attitudes and behaviors of Chinese restaurateurs toward food safety training.

PubMed

Liu, Pei; Kwon, Junehee

2013-06-01

Foodborne illness is a challenge in the production and service of ethnic foods. The purpose of the study described in this article was to explore variables influencing the behaviors of U.S. Chinese restaurant owners/operators regarding the provision of food safety training in their restaurants. Seventeen major Chinese cultural values were identified through individual interviews with 20 Chinese restaurant owners/operators. Most participants felt satisfied with their previous health inspections. Several expressed having difficulty, however, following the health inspectors' instructions and in understanding the health inspection report. A few participants provided food safety training to their employees due to state law. Lack of money, time, labor/energy, and a perceived need for food safety training were recognized as major challenges to providing food safety training in Chinese restaurants. Videos, case studies, and food safety training handbooks were the most preferred food safety training methods of Chinese restaurant owners/operators, and Chinese was the preferred language in which to conduct the training.

Development of Power Supply Management Module for Radio Signal Repeaters of Automatic Metering Reading System in Variable Solar Density Conditions

NASA Astrophysics Data System (ADS)

Kondratjevs, K.; Zabasta, A.; Selmanovs-Pless, V.

2016-02-01

In recent years, there has been significant research focus that revolves around harvesting and minimising energy consumption by wireless sensor network nodes. When a sensor node is depleted of energy, it becomes unresponsive and disconnected from the network that can significantly influence the performance of the whole network. The purpose of the present research is to create a power supply management module in order to provide stable operating voltage for autonomous operations of radio signal repeaters, sensors or gateways of WSN. The developed management module is composed of a solar panel, lithium battery and power supply management module. The novelty of the research is the management module, which ensures stable and uninterrupted operations of electronic equipment in various power supply modes in different situations, simultaneously ensuring energy protection and sustainability of the module components. The management module is able to provide power supply of 5 V for electronics scheme independently, without power interruption switching between power sources and power flows in different directions.

Monte Carlo PDF method for turbulent reacting flow in a jet-stirred reactor

NASA Astrophysics Data System (ADS)

Roekaerts, D.

1992-01-01

A stochastic algorithm for the solution of the modeled scalar probability density function (PDF) transport equation for single-phase turbulent reacting flow is described. Cylindrical symmetry is assumed. The PDF is represented by ensembles of N representative values of the thermochemical variables in each cell of a nonuniform finite-difference grid and operations on these elements representing convection, diffusion, mixing and reaction are derived. A simplified model and solution algorithm which neglects the influence of turbulent fluctuations on mean reaction rates is also described. Both algorithms are applied to a selectivity problem in a real reactor.

Effect of climate on the storage and turnover of carbon in soils

NASA Technical Reports Server (NTRS)

Trumbore, Susan; Chadwick, Oliver; Amundson, Ronald; Brasher, Benny

1994-01-01

Climate is, in many instances, the dominant variable controlling the storage of carbon in soils. It has proven difficult, however, to determine how soil properties influenced by climate, such as soil temperature and soil moisture, actually operate to determine the rates of accumulation and decomposition of soil organic matter. Our approach has been to apply a relatively new tool, the comparison of C-14 in soil organic matter from pre- and post-bomb soils, to quantify carbon turnover rates along climosequences. This report details the progress made toward this end by work under this contract.

[Blood pressure variability: clinical interest or simple curiosity?].

PubMed

Ciaroni, Stefano

2007-03-14

Blood pressure variability is a physiological phenomenon influenced by many internal and external factors. This variability could be also influenced by pathological conditions such as arterial hypertension. Two forms must be mainly distinguished: the blood pressure variability at long and short-term. The latter could only be studied by continuous recordings. In this article will be analysed the interest of measuring blood pressure variability, its cardiovascular prognosis and the therapeutic tools when it is increased.

Measurement of pressure and flow rates during irrigation of a root canal ex vivo with three endodontic needles.

PubMed

Boutsioukis, C; Lambrianidis, T; Kastrinakis, E; Bekiaroglou, P

2007-07-01

To monitor ex vivo intra-canal irrigation with three endodontic needles (25, 27 and 30 gauge) and compare them in terms of irrigant flow rate, intra-barrel pressure, duration of irrigation and volume of irrigant delivered. A testing system was constructed to allow measurement of selected variables with pressure and displacement transducers during ex vivo intra-canal irrigation with a syringe and three different needles (groups A, B, C) into a prepared root canal. Ten specialist endodontists performed the irrigation procedure. Each operator performed ten procedures with each needle. Data recorded by the transducers were analysed using Friedman's test, Wilcoxon Signed Rank test, Mann-Whitney U-test and Kendall's T(b) test. The level of significance was set to 95%. Significant differences were detected among the three needles for most variables. Duration of delivery and flow rates significantly decreased as the needle diameter increased, whilst pressure increased up to 400-550 kPa. Gender of the operator had a significant impact on the results. Experience of the operators (years) were negatively correlated to volume of irrigant (all groups), to the duration of delivery (groups A, B) and to the average flow rate (group A). Finer diameter needles require increased effort to deliver the irrigant and result in higher intra-barrel pressure. The syringe and needles used tolerated the pressure developed. Irrigant flow rate should be considered as a factor directly influencing flow beyond the needle. Wide variations of flow rate were observed among operators. Syringe irrigation appears difficult to standardize and control.

Evaluation of salivary surface tension in a cohort of young healthy adults.

PubMed

Foglio-Bonda, P L; Laguini, E; Davoli, C; Pattarino, F; Foglio-Bonda, A

2018-03-01

To determine salivary pH, flow rate (FR) and surface tension (γs) in a cohort of 30 healthy young adults. To acquire cohort biological independent variables (age, gender, weight, height, medications, smoking, pathologies, and allergies) and to correlate them with pH, FR and γs obtained values. Evaluate the possible variation of the γs values during the time after the withdrawal and the influence of the operational abilities of the experimenting operators. Evaluate the relationship between γs, pH and FR  and the dependence between pH and FR. Non-stimulated saliva samples were taken in four different time span, for three days, with a drooling method for 15 minutes. The saliva sample was analyzed, in terms of γs, by two different operators (OP1 and OP2), twice consecutive (γs-1 and γs-2) for a total of 360 measurements. The γs was calculated using the du Noüy method. The FR was evaluated by weighing technique and pH by pH indicator papers. The measurements of γs performed by two different operators (OP1, OP2) showed respectively average values of 46.46 mN/m and 43.45 mN/m, while the mean FR was 0.29 ± 0.13 mL/min and the average pH was 7.1 ± 0.43. There were no significant correlations between γs and the biological variables analyzed. We can consider as reference values, in a sample of young adults, γs 45.56 ± 6.51 mN/m.

Concurrently adjusting interrelated control parameters to achieve optimal engine performance

DOEpatents

Jiang, Li; Lee, Donghoon; Yilmaz, Hakan; Stefanopoulou, Anna

2015-12-01

Methods and systems for real-time engine control optimization are provided. A value of an engine performance variable is determined, a value of a first operating condition and a value of a second operating condition of a vehicle engine are detected, and initial values for a first engine control parameter and a second engine control parameter are determined based on the detected first operating condition and the detected second operating condition. The initial values for the first engine control parameter and the second engine control parameter are adjusted based on the determined value of the engine performance variable to cause the engine performance variable to approach a target engine performance variable. In order to cause the engine performance variable to approach the target engine performance variable, adjusting the initial value for the first engine control parameter necessitates a corresponding adjustment of the initial value for the second engine control parameter.

Analysis of cash flow in academic medical centers in the United States.

PubMed

McCue, Michael J; Thompson, Jon M

2011-09-01

To examine cash flow margins in academic medical centers (AMCs; i.e., teaching hospitals) in an effort both to determine any significant differences in a set of operational and financial factors known to influence cash flow for high- and low-cash-flow AMCs and to discuss how these findings affect AMC operations. The authors sampled the Medicare cost report data of 103 AMCs for fiscal years 2005, 2006, and 2007, and then they applied the t test to test for significant mean differences between the two cash flow groups across operational and financial variables (e.g., case mix, operating margin). Compared with low-cash-flow AMCs, high-cash-flow AMCs were larger-bed-size facilities, treated cases of greater complexity, generated higher net patient revenue per adjusted discharge, served a significantly lower percentage of Medicaid patients, had significantly higher average operating profit margins and cash flow margin ratios, possessed a higher number of days of cash on hand, and collected their receivables more quickly. Study findings imply that high-cash-flow AMCs were earning higher cash flow returns than low-cash-flow AMCs, which may be because high-cash-flow AMCs generate higher patient revenues while serving fewer lower-paying Medicaid patients.

The GRACE Mission in the Final Stage

NASA Astrophysics Data System (ADS)

Tapley, B. D.; Flechtner, F.; Watkins, M. M.; Boening, C.; Bettadpur, S. V.

2016-12-01

The twin satellites of the Gravity Recovery and Climate Experiment (GRACE) were launched on March 17, 2002 and have operated for over 13 years. The mission objectives are to sense the spatial and temporal variations of the Earth's mass through its effects on the gravity field at the GRACE satellite altitude. The major cause of the time varying mass is water motion and the GRACE mission has provided a continuous decade long measurement sequences which characterizes the seasonal cycle of mass transport between the oceans, land, cryosphere and atmosphere; its inter-annual variability; and the climate driven secular, or long period, mass transport signals. The mission is entering the final phase of operations. The current mission operations strategy emphasizes extending the mission lifetime to achieve mission overlap with the GRACE Follow On Mission, whose launch is scheduled for late 2017. The mission operations decisions necessary to extend the mission lifetime impact both the science data yield and the data quality. This presentation will review the mission status, the projections for mission lifetime, summarize plans for the RL 06 data re-analysis, describe the issues that influence the operations philosophy and discuss the impact on the science data products during the remaining mission lifetime.

Cognitive processing variables in breast cancer: worry and distress at the end of treatment.

PubMed

Costa-Requena, Gema; Rodríguez, Ana; Fernández, Rosina; Palomera, Elisabet; Gil, Francisco L

2011-06-01

This study assessed the influence of cognitive processing variables on cancer worries and distress after breast cancer treatment. In multivariate analyses, while independent variables were intolerance of uncertainty and intrusive thoughts, constructs' variables were anxiety and depression symptoms and cancer-related worries. The intolerance to uncertainty had a tendency to influence on distress and concerns about cancer after the end of treatment (Wilks' λ = 0.687, p = 0.074). Whereas, thought intrusion had a significant influence on distress and cancer related worries (Wilks' λ = 0.228, p = 0.000). Cognitive variables could be addressed by the oncology nurse when considering the patients' concerns related to cancer and psychological distress.

Distortions in recall from visual memory: two classes of attractors at work.

PubMed

Huang, Jie; Sekuler, Robert

2010-02-24

In a trio of experiments, a matching procedure generated direct, analogue measures of short-term memory for the spatial frequency of Gabor stimuli. Experiment 1 showed that when just a single Gabor was presented for study, a retention interval of just a few seconds was enough to increase the variability of matches, suggesting that noise in memory substantially exceeds that in vision. Experiment 2 revealed that when a pair of Gabors was presented on each trial, the remembered appearance of one of the Gabors was influenced by: (1) the relationship between its spatial frequency and the spatial frequency of the accompanying, task-irrelevant non-target stimulus; and (2) the average spatial frequency of Gabors seen on previous trials. These two influences, which work on very different time scales, were approximately additive in their effects, each operating as an attractor for remembered appearance. Experiment 3 showed that a timely pre-stimulus cue allowed selective attention to curtail the influence of a task-irrelevant non-target, without diminishing the impact of the stimuli seen on previous trials. It appears that these two separable attractors influence distinct processes, with perception being influenced by the non-target stimulus and memory being influenced by stimuli seen on previous trials.

The Role of Policy and Institutions on Health Spending.

PubMed

de la Maisonneuve, Christine; Moreno-Serra, Rodrigo; Murtin, Fabrice; Oliveira Martins, Joaquim

2017-07-01

This paper investigates the impact of policies and institutions on health expenditures for a large panel of Organisation for Economic Co-operation and Development countries for the period of 2000-2010. A set of 20 policy and institutional indicators developed by the Organisation for Economic Co-operation and Development are integrated into a theoretically motivated econometric framework, alongside control variables related to demographic (dependency ratio) and non-demographic (income, prices and technology) drivers of health expenditures per capita. Although a large share of cross-country differences in public health expenditures can be explained by demographic and economic factors (around 71%), cross-country variations in policies and institutions also have a significant influence, explaining most of the remaining difference in public health spending (23%). Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Method and apparatus for executing an asynchronous clutch-to-clutch shift in a hybrid transmission

DOEpatents

Demirovic, Besim; Gupta, Pinaki; Kaminsky, Lawrence A.; Naqvi, Ali K.; Heap, Anthony H.; Sah, Jy-Jen F.

2014-08-12

A hybrid transmission includes first and second electric machines. A method for operating the hybrid transmission in response to a command to execute a shift from an initial continuously variable mode to a target continuously variable mode includes increasing torque of an oncoming clutch associated with operating in the target continuously variable mode and correspondingly decreasing a torque of an off-going clutch associated with operating in the initial continuously variable mode. Upon deactivation of the off-going clutch, torque outputs of the first and second electric machines and the torque of the oncoming clutch are controlled to synchronize the oncoming clutch. Upon synchronization of the oncoming clutch, the torque for the oncoming clutch is increased and the transmission is operated in the target continuously variable mode.

Integrative Motivation: Changes during a Year-Long Intermediate-Level Language Course

ERIC Educational Resources Information Center

Gardner, R. C.; Masgoret, A. M.; Tennant, J.; Mihic, L.

2004-01-01

The socioeducational model of second language acquisition postulates that language learning is a dynamic process in which affective variables influence language achievement and achievement and experiences in language learning can influence some affective variables. Five classes of variable are emphasized: integrativeness, attitudes toward the…

Nonmetropolitan Migration: The Influence of Neglected Variables.

ERIC Educational Resources Information Center

Cook, Annabel Kirschner

1987-01-01

Compares influence of employment growth/diversity, commuting, retirement migration, income, unemployment, age structure, and adjacency with influence of nonfarm self-employment and percentage of labor force that is female on recent declines in nonmetropolitan growth rates. Suggests last two variables are more important determinants of…

Variability of the raindrop size distribution at small spatial scales

NASA Astrophysics Data System (ADS)

Berne, A.; Jaffrain, J.

2010-12-01

Because of the interactions between atmospheric turbulence and cloud microphysics, the raindrop size distribution (DSD) is strongly variable in space and time. The spatial variability of the DSD at small spatial scales (below a few km) is not well documented and not well understood, mainly because of a lack of adequate measurements at the appropriate resolutions. A network of 16 disdrometers (Parsivels) has been designed and set up over EPFL campus in Lausanne, Switzerland. This network covers a typical operational weather radar pixel of 1x1 km2. The question of the significance of the variability of the DSD at such small scales is relevant for radar remote sensing of rainfall because the DSD is often assumed to be uniform within a radar sample volume and because the Z-R relationships used to convert the measured radar reflectivity Z into rain rate R are usually derived from point measurements. Thanks to the number of disdrometers, it was possible to quantify the spatial variability of the DSD at the radar pixel scale and to show that it can be significant. In this contribution, we show that the variability of the total drop concentration, of the median volume diameter and of the rain rate are significant, taking into account the sampling uncertainty associated with disdrometer measurements. The influence of this variability on the Z-R relationship can be non-negligible. Finally, the spatial structure of the DSD is quantified using a geostatistical tool, the variogram, and indicates high spatial correlation within a radar pixel.

Control model design to limit DC-link voltage during grid fault in a dfig variable speed wind turbine

NASA Astrophysics Data System (ADS)

Nwosu, Cajethan M.; Ogbuka, Cosmas U.; Oti, Stephen E.

2017-08-01

This paper presents a control model design capable of inhibiting the phenomenal rise in the DC-link voltage during grid- fault condition in a variable speed wind turbine. Against the use of power circuit protection strategies with inherent limitations in fault ride-through capability, a control circuit algorithm capable of limiting the DC-link voltage rise which in turn bears dynamics that has direct influence on the characteristics of the rotor voltage especially during grid faults is here proposed. The model results so obtained compare favorably with the simulation results as obtained in a MATLAB/SIMULINK environment. The generated model may therefore be used to predict near accurately the nature of DC-link voltage variations during fault given some factors which include speed and speed mode of operation, the value of damping resistor relative to half the product of inner loop current control bandwidth and the filter inductance.

High flow and riparian vegetation along the San Miguel River, Colorado

USGS Publications Warehouse

Friedman, J.M.; Auble, G.T.

2000-01-01

Riparian ecosystems are characterized by abundance of water and frequent flow related disturbance. River regulation typically decreases peak flows, reducing the amount of disturbance and altering the vegetation. The San Miguel River is one of the last relatively unregulated rivers remaining in the Colorado River Watershed. One goal of major landowners along the San Miguel including the Bureau of Land Management and The Nature Conservancy is to maintain their lands in a natural condition. Conservation of an entire river corridor requires an integrated understanding of the variability in ecosystems and external influences along the river. Therefore, the Bureau of Land Management and others have fostered a series of studies designed to catalogue that variability, and to characterize the processes that maintain the river as a whole. In addition to providing information useful to managers, these studies present a rare opportunity to investigate how a Colorado river operates in the absence of regulation.

A Thermodynamic Study of the Turbojet Engine

NASA Technical Reports Server (NTRS)

Pinkel, Benjamin; Karp, Irvin M

1947-01-01

Charts are presented for computing thrust, fuel consumption, and other performance values of a turbojet engine for any given set of operating conditions and component efficiencies. The effects of pressure losses in the inlet duct and the combustion chamber, of variation in physical properties of the gas as it passes through the system, of reheating of the gas due to turbine losses, and of change in mass flow by the addition of fuel are included. The principle performance chart shows the effects of primary variables and correction charts provide the effects of secondary variables and of turbine-loss reheat on the performance of the system. The influence of characteristics of a given compressor and turbine on performance of a turbojet engine containing a matched set of these given components is discussed for cases of an engine with a centrifugal-flow compressor and of an engine with an axial-flow compressor.

Culture as a variable in neuroscience and clinical neuropsychology: A comprehensive review

PubMed Central

Wajman, José Roberto; Bertolucci, Paulo Henrique Ferreira; Mansur, Letícia Lessa; Gauthier, Serge

2015-01-01

Culture is a dynamic system of bidirectional influences among individuals and their environment, including psychological and biological processes, which facilitate adaptation and social interaction. One of the main challenges in clinical neuropsychology involves cognitive, behavioral and functional assessment of people with different sociocultural backgrounds. In this review essay, examining culture from a historical perspective to ethical issues in cross-cultural research, including the latest significant and publications, the authors sought to explore the main features related to cultural variables in neuropsychological practice and to debate the challenges found regarding the operational methods currently in use. Literature findings suggest a more comprehensive approach in cognitive and behavioral neuroscience, including an interface between elementary disciplines and applied neuropsychology. Thus, as a basis for discussion on this issue, the authors analyzed key-topics related to the study of new trends in sociocultural neuroscience and the application of their concepts from a clinical perspective. PMID:29213964

Effects of seasonal operation on the quality of water produced by public-supply wells.

PubMed

Bexfield, Laura M; Jurgens, Bryant C

2014-09-01

Seasonal variability in groundwater pumping is common in many places, but resulting effects of seasonal pumping stress on the quality of water produced by public-supply wells are not thoroughly understood. Analysis of historical water-quality samples from public-supply wells completed in deep basin-fill aquifers in Modesto, California (134 wells) and Albuquerque, New Mexico (95 wells) indicates that several wells have seasonal variability in concentrations of contaminants of concern. In Modesto, supply wells are more likely to produce younger groundwater with higher nitrate and uranium concentrations during the summer (high) pumping season than during the winter (low) pumping season. In Albuquerque, supply wells are more likely to produce older groundwater with higher arsenic concentrations during the winter pumping season than during the summer pumping season. Seasonal variability in contaminant concentrations in Modesto is influenced primarily by effects of summer pumping on vertical hydraulic gradients that drive migration of shallow groundwater through the aquifer to supply wells. Variability in Albuquerque is influenced primarily by the period of time that a supply well is idle, allowing its wellbore to act as a conduit for vertical groundwater flow and contaminant migration. However, both processes are observed in each study area. Similar findings would appear to be likely in other alluvial basins with stratified water quality and substantial vertical head gradients. Results suggest that even in aquifers dominated by old groundwater, changes to seasonal pumping patterns and/or to depth of well completion can help reduce vulnerability to selected contaminants of either natural or anthropogenic origin. Published 2014. This article is a U.S. Government work and is in the public domain in the USA. Groundwater published by Wiley Periodicals, Inc. on behalf of National Ground Water Association.

The focus on sample quality: Influence of colon tissue collection on reliability of qPCR data

PubMed Central

Korenkova, Vlasta; Slyskova, Jana; Novosadova, Vendula; Pizzamiglio, Sara; Langerova, Lucie; Bjorkman, Jens; Vycital, Ondrej; Liska, Vaclav; Levy, Miroslav; Veskrna, Karel; Vodicka, Pavel; Vodickova, Ludmila; Kubista, Mikael; Verderio, Paolo

2016-01-01

Successful molecular analyses of human solid tissues require intact biological material with well-preserved nucleic acids, proteins, and other cell structures. Pre-analytical handling, comprising of the collection of material at the operating theatre, is among the first critical steps that influence sample quality. The aim of this study was to compare the experimental outcomes obtained from samples collected and stored by the conventional means of snap freezing and by PAXgene Tissue System (Qiagen). These approaches were evaluated by measuring rRNA and mRNA integrity of the samples (RNA Quality Indicator and Differential Amplification Method) and by gene expression profiling. The collection procedures of the biological material were implemented in two hospitals during colon cancer surgery in order to identify the impact of the collection method on the experimental outcome. Our study shows that the pre-analytical sample handling has a significant effect on the quality of RNA and on the variability of qPCR data. PAXgene collection mode proved to be more easily implemented in the operating room and moreover the quality of RNA obtained from human colon tissues by this method is superior to the one obtained by snap freezing. PMID:27383461

Solid phase microbial fuel cell (SMFC) for harnessing bioelectricity from composite food waste fermentation: influence of electrode assembly and buffering capacity.

PubMed

Mohan, S Venkata; Chandrasekhar, K

2011-07-01

Solid phase microbial fuel cells (SMFC; graphite electrodes; open-air cathode) were designed to evaluate the potential of bioelectricity production by stabilizing composite canteen based food waste. The performance was evaluated with three variable electrode-membrane assemblies. Experimental data depicted feasibility of bioelectricity generation from solid state fermentation of food waste. Distance between the electrodes and presence of proton exchange membrane (PEM) showed significant influence on the power yields. SMFC-B (anode placed 5 cm from cathode-PEM) depicted good power output (463 mV; 170.81 mW/m(2)) followed by SMFC-C (anode placed 5 cm from cathode; without PEM; 398 mV; 53.41 mW/m(2)). SMFC-A (PEM sandwiched between electrodes) recorded lowest performance (258 mV; 41.8 mW/m(2)). Sodium carbonate amendment documented marked improvement in power yields due to improvement in the system buffering capacity. SMFCs operation also documented good substrate degradation (COD, 76%) along with bio-ethanol production. The operation of SMFC mimicked solid-sate fermentation which might lead to sustainable solid waste management practices. Copyright © 2011 Elsevier Ltd. All rights reserved.

Influence of Peanut Cultivars and Environmental Conditions on the Diversity and Community Composition of Pod Rot Soil Fungi in China.

PubMed

Wang, Mian; Chen, Mingna; Yang, Zhen; Chen, Na; Chi, Xiaoyuan; Pan, Lijuan; Wang, Tong; Yu, Shanlin; Guo, Xingqi

2017-12-01

Peanut yield and quality are seriously affected by pod rot pathogens worldwide, especially in China in recent years. The goals of this study are to analyze the structure of fungal communities of peanut pod rot in soil in three peanut cultivars and the correlation of pod rot with environmental variables using 454 pyrosequencing. A total of 46,723 internal transcribed spacer high-quality sequences were obtained and grouped into 1,706 operational taxonomic units at the 97% similarity cut-off level. The coverage, rank abundance, and the Chao 1 and Shannon diversity indices of the operational taxonomic units were analyzed. Members of the phylum Ascomycota were dominant, such as Fusarium , Chaetomium , Alternaria , and Sordariomycetes , followed by Basidiomycota. The results of the heatmap and redundancy analysis revealed significant variation in the composition of the fungal community among the three cultivar samples. The environmental conditions in different peanut cultivars may also influence on the structure of the fungal community. The results of this study suggest that the causal agent of peanut pod rot may be more complex, and cultivars and environmental conditions are both important contributors to the community structure of peanut pod rot fungi.

Planned versus actual outcomes as a result of animal feeding operation decisions for managing phosphorus.

PubMed

Cabot, Perry E; Nowak, Pete

2005-01-01

The paper explores how decisions made on animal feeding operations (AFOs) influence the management of manure and phosphorus. Variability among these decisions from operation to operation and from field to field can influence the validity of nutrient loss risk assessments. These assessments are based on assumptions that the decision outcomes regarding manure distribution will occur as they are planned. The discrepancy between planned versus actual outcomes in phosphorus management was explored on nine AFOs managing a contiguous set of 210 fields in south-central Wisconsin. A total of 2611 soil samples were collected and multiple interviews conducted to assign phosphorus index (PI) ratings to the fields. Spearman's rank correlation coefficients (r(S)) indicated that PI ratings were less sensitive to soil test phosphorus (STP) levels (r(S) = 0.378), universal soil loss equation (USLE) (r(S) = 0.261), ratings for chemical fertilizer application (r(S) = 0.185), and runoff class (r(S) = -0.089), and more sensitive to ratings for manure application (r(S) = 0.854). One-way ANOVA indicated that mean field STP levels were more homogenous than field PI ratings between AFOs. Kolmogorov-Smirnov (K-S) tests displayed several nonsignificant comparisons for cumulative distribution functions, S(x), of mean STP levels on AFO fields. On the other hand, the K-S tests of S(x) for PI ratings indicated that the majority of these S(x) functions were significantly different between AFOs at or greater than the 0.05 significance level. Interviews suggested multiple reasons for divergence between planned and actual outcomes in managing phosphorus, and that this divergence arises at the strategic, tactical, and operational levels of decision-making.

Influence of Family Structure and School Variables on Behavior Disorders of Children

ERIC Educational Resources Information Center

Lindholm, Byron W.; And Others

1977-01-01

This study examined the influence of family structure and school variables on behavior disorders of children (N=1,162). Results indicated grade in school, sex, social class, ordinal position in the family, and teacher were important variables in the determination of behavior disorders. (Author)

Environmental Literacy in Madeira Island (Portugal): The Influence of Demographic Variables

ERIC Educational Resources Information Center

Spinola, Hélder

2016-01-01

Demographic factors are among those that influence environmental literacy and, particularly, environmentally responsible behaviours, either directly or due to an aggregation effect dependent on other types of variables. Present study evaluates a set of demographic variables as predictors for environmental literacy among 9th grade students from…

Background, Personal, and Environmental Influences on the Career Planning of Adolescent Girls

ERIC Educational Resources Information Center

Novakovic, Alexandra; Fouad, Nadya A.

2013-01-01

This study investigated the influence of background variables (age, race/ethnicity, mother's work status outside of the home, and socioeconomic status), personal variables (anticipatory role conflict and academic self-efficacy), and environmental variables (parental attachment and parental support) on aspects of adolescent girls' career planning.…

Against Conventional Wisdom: Factors Influencing Hispanic Students' Reading Achievement

ERIC Educational Resources Information Center

Percell, Jay C.; Kaufman, Kristina

2013-01-01

The researchers performed a variable analysis of the 2002 Educational Longitudinal Study data investigating factors that influence students' reading scores on standardized tests. Hispanic and non-Hispanic Scores were analyzed and controlling variables were compared to determine the effect of each on both populations. Certain variables commonly…

Investments and costs of oral health care for Family Health Care

PubMed Central

Macêdo, Márcia Stefânia Ribeiro; Chaves, Sônia Cristina Lima; Fernandes, Antônio Luis de Carvalho

2016-01-01

ABSTRACT OBJECTIVE To estimate the investments to implement and operational costs of a type I Oral Health Care Team in the Family Health Care Strategy. METHODS This is an economic assessment study, for analyzing the investments and operational costs of an oral health care team in the city of Salvador, BA, Northeastern Brazil. The amount worth of investments for its implementation was obtained by summing up the investments in civil projects and shared facilities, in equipments, furniture, and instruments. Regarding the operational costs, the 2009-2012 time series was analyzed and the month of December 2012 was adopted for assessing the monetary values in effect. The costs were classified as direct variable costs (consumables) and direct fixed costs (salaries, maintenance, equipment depreciation, instruments, furniture, and facilities), besides the indirect fixed costs (cleaning, security, energy, and water). The Ministry of Health’s share in funding was also calculated, and the factors that influence cost behavior were described. RESULTS The investment to implement a type I Oral Health Care Team was R$29,864.00 (US$15,236.76). The operational costs of a type I Oral Health Care Team were around R$95,434.00 (US$48,690.82) a year. The Ministry of Health’s financial incentives for investments accounted for 41.8% of the implementation investments, whereas the municipality contributed with a 59.2% share of the total. Regarding operational costs, the Ministry of Health contributed with 33.1% of the total, whereas the municipality, with 66.9%. Concerning the operational costs, the element of heaviest weight was salaries, which accounted for 84.7%. CONCLUSIONS Problems with the regularity in the supply of inputs and maintenance of equipment greatly influence the composition of costs, besides reducing the supply of services to the target population, which results in the service probably being inefficient. States are suggested to partake in funding, especially to cover the team’s operational cost. PMID:27463254

Influence of the Ultrasonic Power Applied on Freeze Drying Kinetics

NASA Astrophysics Data System (ADS)

Brines, C.; Mulet, A.; García-Pérez, J. V.; Riera, E.; Cárcel, J. A.

The atmospheric freeze drying (AFD) constitutes an interesting alternative to vacuum freeze drying providing products with similar quality at lowest cost. However, the long process time needed represent an important drawback. In this sense, the application of high intensity ultrasound can enhance heat and mass transfer and intensify the operation. In hot air drying operation, the ultrasonic effects are dependent on the process variables such as air velocity, internal sample structure or ultrasonic power applied. However, in AFD processes, the internal structure of material or the air velocity has not significant influence on the magnitude of ultrasonic effects. The aim of this work was to determine the influence on drying kinetics of the ultrasonic power applied during the AFD of apple. For that purpose, AFD experiments (-10 °C, 2 m/s and 15% relative humidity) of apple slabs (cv. Granny Smith, 30 x 30 x 10 mm) were carried out with ultrasound application (21 kHz) at different power levels (0, 10.3, 20.5 and 30.8 kW/m3). The drying kinetics was obtained from the initial moisture content and the weight evolution of samples during drying. Experimental results showed a significant (p<0.05) influence of the ultrasound application on drying. Thus, drying time was shorter as higher the ultrasonic power applied. From modeling, it was observed that the effective diffusion coefficient identified was 4.8 times higher when ultrasound was applied at the lowest power tested (10.3 kW/m3) that illustrated the high intensification potential of ultrasound application in the AFD.

Force-Sensing Enhanced Simulation Environment (ForSense) for laparoscopic surgery training and assessment.

PubMed

Cundy, Thomas P; Thangaraj, Evelyn; Rafii-Tari, Hedyeh; Payne, Christopher J; Azzie, Georges; Sodergren, Mikael H; Yang, Guang-Zhong; Darzi, Ara

2015-04-01

Excessive or inappropriate tissue interaction force during laparoscopic surgery is a recognized contributor to surgical error, especially for robotic surgery. Measurement of force at the tool-tissue interface is, therefore, a clinically relevant skill assessment variable that may improve effectiveness of surgical simulation. Popular box trainer simulators lack the necessary technology to measure force. The aim of this study was to develop a force sensing unit that may be integrated easily with existing box trainer simulators and to (1) validate multiple force variables as objective measurements of laparoscopic skill, and (2) determine concurrent validity of a revised scoring metric. A base plate unit sensitized to a force transducer was retrofitted to a box trainer. Participants of 3 different levels of operative experience performed 5 repetitions of a peg transfer and suture task. Multiple outcome variables of force were assessed as well as a revised scoring metric that incorporated a penalty for force error. Mean, maximum, and overall magnitudes of force were significantly different among the 3 levels of experience, as well as force error. Experts were found to exert the least force and fastest task completion times, and vice versa for novices. Overall magnitude of force was the variable most correlated with experience level and task completion time. The revised scoring metric had similar predictive strength for experience level compared with the standard scoring metric. Current box trainer simulators can be adapted for enhanced objective measurements of skill involving force sensing. These outcomes are significantly influenced by level of expertise and are relevant to operative safety in laparoscopic surgery. Conventional proficiency standards that focus predominantly on task completion time may be integrated with force-based outcomes to be more accurately reflective of skill quality. Copyright © 2015 Elsevier Inc. All rights reserved.

Design and dynamic simulation of a fixed pitch 56 kW wind turbine drive train with a continuously variable transmission

NASA Technical Reports Server (NTRS)

Gallo, C.; Kasuba, R.; Pintz, A.; Spring, J.

1986-01-01

The dynamic analysis of a horizontal axis fixed pitch wind turbine generator (WTG) rated at 56 kW is discussed. A mechanical Continuously Variable Transmission (CVT) was incorporated in the drive train to provide variable speed operation capability. One goal of the dynamic analysis was to determine if variable speed operation, by means of a mechanical CVT, is capable of capturing the transient power in the WTG/wind environment. Another goal was to determine the extent of power regulation possible with CVT operation.

The influence of controlled floods on fine sediment storage in debris fan-affected canyons of the Colorado River basin

USGS Publications Warehouse

Mueller, Erich R.; Grams, Paul E.; Schmidt, John C.; Hazel, Joseph E.; Alexander, Jason S.; Kaplinski, Matt

2014-01-01

Prior to the construction of large dams on the Green and Colorado Rivers, annual floods aggraded sandbars in lateral flow-recirculation eddies with fine sediment scoured from the bed and delivered from upstream. Flows greater than normal dam operations may be used to mimic this process in an attempt to increase time-averaged sandbar size. These controlled floods may rebuild sandbars, but sediment deficit conditions downstream from the dams restrict the frequency that controlled floods produce beneficial results. Here, we integrate complimentary, long-term monitoring data sets from the Colorado River in Marble and Grand Canyons downstream from Glen Canyon dam and the Green River in the Canyon of Lodore downstream from Flaming Gorge dam. Since the mid-1990s, several controlled floods have occurred in these canyon rivers. These controlled floods scour fine sediment from the bed and build sandbars in eddies, thus increasing channel relief. These changes are short-lived, however, as interflood dam operations erode sandbars within several months to years. Controlled flood response and interflood changes in bed elevation are more variable in Marble Canyon and Grand Canyon, likely reflecting more variable fine sediment supply and stronger transience in channel bed sediment storage. Despite these differences, neither system shows a trend in fine-sediment storage during the period in which controlled floods were monitored. These results demonstrate that controlled floods build eddy sandbars and increase channel relief for short interflood periods, and this response may be typical in other dam-influenced canyon rivers. The degree to which these features persist depends on the frequency of controlled floods, but careful consideration of sediment supply is necessary to avoid increasing the long-term sediment deficit.

Preliminary screening oxidative degradation methyl orange using ozone/ persulfate

NASA Astrophysics Data System (ADS)

Aqilah Razali, Nur; Zulzikrami Azner Abidin, Che; An, Ong Soon; Ridwan, Fahmi Muhammad; Haqi Ibrahim, Abdul; Nasuha Sabri, Siti; Huan Kow, Su

2018-03-01

The present study focusing on the performances of advanced oxidation process by using ozonation method towards Methyl Orange based on the efficiency of colour removal and Chemical Oxygen Demand (COD) removal. Factorial design with response surface methodology (RSM) was used to evaluate the interaction between operational conditions, such as pH, initial concentration, contact time and persulfate dosage to obtain the optimum range conditions using a semi-batch reactor. The range of independent variables investigated were pH (3-11), initial concentration (100-500mg/L), contact time (10-50min) and persulfate dosage (20-100mM) while the response variables were colour removal and COD removal of Methyl Orange. The experimental results and statistical analysis showed all the parameters were significant. Thus, from this findings, optimization of operational conditions that had been suggested from the ozone/persulfate RSM analysis were (pH 3, 100 mg/L, 50min, 60mM) that would be produced 99% Colour Removal and 80% COD Removal and help in promoting an efficient ozonation process. The effect list data that showed the most contributed effects to increase the percentages of colour removal were pH and persulfate dosage whereas the contact time and initial concentration had the highest positive effects on the COD removal. Other than that, the interaction between pH, contact time and persulfate dosage were found to be the most influencing interaction. Therefore the least influencing interaction was interaction between persulfate dosage and pH. In this study, the correlation coefficient value R2 for colour removal and COD removal of Methyl Orange were R2= 0.9976 and R2= 0.9924 which suggested a good fit of the first-order regression model with the experimental data.

Validation of post-operative residual contrast enhancing tumor volume as an independent prognostic factor for overall survival in newly diagnosed glioblastoma.

PubMed

Ellingson, Benjamin M; Abrey, Lauren E; Nelson, Sarah J; Kaufmann, Timothy J; Garcia, Josep; Chinot, Olivier; Saran, Frank; Nishikawa, Ryo; Henriksson, Roger; Mason, Warren P; Wick, Wolfgang; Butowski, Nicholas; Ligon, Keith L; Gerstner, Elizabeth R; Colman, Howard; de Groot, John; Chang, Susan; Mellinghoff, Ingo; Young, Robert J; Alexander, Brian M; Colen, Rivka; Taylor, Jennie W; Arrillaga-Romany, Isabel; Mehta, Arnav; Huang, Raymond Y; Pope, Whitney B; Reardon, David; Batchelor, Tracy; Prados, Michael; Galanis, Evanthia; Wen, Patrick Y; Cloughesy, Timothy F

2018-04-05

In the current study, we pooled imaging data in newly diagnosed GBM patients from international multicenter clinical trials, single institution databases, and multicenter clinical trial consortiums to identify the relationship between post-operative residual enhancing tumor volume and overall survival (OS). Data from 1,511 newly diagnosed GBM patients from 5 data sources were included in the current study: 1) a single institution database from UCLA (N=398; Discovery); 2) patients from the Ben and Cathy Ivy Foundation for Early Phase Clinical Trials Network Radiogenomics Database (N=262 from 8 centers; Confirmation); 3) the chemoradiation placebo arm from an international phase III trial (AVAglio; N=394 from 120 locations in 23 countries; Validation); 4) the experimental arm from AVAglio examining chemoradiation plus bevacizumab (N=404 from 120 locations in 23 countries; Exploratory Set 1); and 5) an Alliance (N0874) Phase I/II trial of vorinostat plus chemoradiation (N=53; Exploratory Set 2). Post-surgical, residual enhancing disease was quantified using T1 subtraction maps. Multivariate Cox regression models were used to determine influence of clinical variables, MGMT status, and residual tumor volume on OS. A log-linear relationship was observed between post-operative, residual enhancing tumor volume and OS in newly diagnosed GBM treated with standard chemoradiation. Post-operative tumor volume is a prognostic factor for OS (P<0.01), regardless of therapy, age, and MGMT promoter methylation status. Post-surgical, residual contrast-enhancing disease significantly negatively influences survival in patients with newly diagnosed glioblastoma treated with chemoradiation with or without concomitant experimental therapy.

Inter- and intraobserver variability of (semi-)quantitative parameters commonly used in feline thyroid scintigraphy.

PubMed

Volckaert, Veerle; Vandermeulen, Eva; Duchateau, Luc; Saunders, Jimmy H; Peremans, Kathelijne

2016-04-01

The aim of this study was to assess inter- and intraobserver variability of commonly used semi-quantitative and quantitative parameters in feline thyroid scintigraphy: thyroid to salivary gland ratio (T/S), thyroid to background ratio (T/B) and the percentage technetium pertechnetate uptake for the thyroid glands (%TcUT). These parameters are being used to diagnose thyroid disease and to assess its severity, but may be influenced by operator related factors when processing the images. Additionally, inter- and intraobserver variability of the percentage technetium pertechnetate uptake for the salivary glands was determined (%TcUSG). The study included technetium pertechnetate scans of 100 hyperthyroid cats. Variability within and between three observers was determined using a random effects model and variance components were estimated by the restricted maximum likelihood procedure. The %TcU for the thyroid and salivary glands, as well as the T/S ratio, showed little to no difference in inter- and intraobserver variability, whereas this was clearly present for the T/B ratio. Overall, the T/S ratio and %TcUSG showed a good repeatability and reproducibility with low inter- and intraobserver variabilities. Inter- and intraobserver variability was higher for the %TcUT, however variations were still considered to be acceptable. On the contrary, inter- and intraobserver variability was clearly larger for the T/B ratio. These findings suggest the preferential use of the T/S ratio or %TcU, especially in facilities with a less experienced staff. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

The Influences and Outcomes of Phonological Awareness: A Study of MA, PA and Auditory Processing in Pre-Readers with a Family Risk of Dyslexia

ERIC Educational Resources Information Center

Law, Jeremy M.; Wouters, Jan; Ghesquière, Pol

2017-01-01

The direct influence of phonological awareness (PA) on reading outcomes has been widely demonstrated, yet PA may also exert indirect influence on reading outcomes through other cognitive variables such as morphological awareness (MA). However, PA's own development is dependent and influenced by many extraneous variables such as auditory…

Study of bituminous surface treatments in Virginia : analysis of factors that significantly influence the quality of bituminous surface treatments.

DOT National Transportation Integrated Search

1970-01-01

It is obvious that many variables may influence the quality of a surface treatment, but the relative importance of the many variables involved is a matter of conjecture. The purpose of this study was to define those variables which do significantly i...

Variables Influencing Teacher Autonomy, Administrative Coordination, and Collaboration

ERIC Educational Resources Information Center

Prichard, Caleb; Moore, Jana E.

2016-01-01

Purpose: Schools often vary in how they balance teacher autonomy (TA) and administrative control, and research suggests that there may be several context-specific variables which may be influential. The purpose of this paper is to determine the influence of program variables on the level of TA, administrative coordination, and administration-staff…

The Attitudes of First Year Senior Secondary School Students toward Their Science Classes in the Sudan

NASA Astrophysics Data System (ADS)

Lado, Longun Moses

This study examined the influence of a set of relevant independent variables on students' decision to major in math or science disciplines, on the one hand, or arts or humanities disciplines, on the other. The independent variables of interest in the study were students' attitudes toward science, their gender, their socioeconomic status, their age, and the strength and direction of parents' and peers' influences on their academic decisions. The study answered five research questions that concerned students' intention in math or science, the association between students' attitudes and their choice to major in math or science, the extent to which parents' and peers' perspectives influence students' choice of major, and the influence of a combination of relevant variables on students' choice of major. The scholarly context for the study was literature relating to students' attitudes toward science and math, their likelihood of taking courses or majoring in science or math and various conditions influencing their attitudes and actions with respect to enrollment in science or math disciplines. This literature suggested that students' experiences, their gender, parents' and peers' influence, their socio-economic status, teachers' treatment of them, school curricula, school culture, and other variables may influence students' attitudes toward science and math and their decision regarding the study of these subjects. The study used a questionnaire comprised of 28 items to elicit information from students. Based upon cluster sampling of secondary schools, the researcher surveyed 1000 students from 10 secondary schools and received 987 responses. The researcher used SPSS to analyze students' responses. Descriptive statistics, logistic regression, and multiple regression analyses to provide findings that address the study's research questions. The following are the major findings from the study: (1) The instrument used to measure students' attitudes toward science and mathematics was not highly reliable, perhaps contributing to an attenuation of the relationship between attitude toward science and mathematics and choice of a science or mathematics major (rather than an arts or humanities major). (2) Far more students than the researcher had anticipated provided responses indicating that they planned to major in a science or mathematics discipline rather than an arts or humanities discipline. (3) Students' attitudes towards math and science were more favorable than the researcher anticipated based on findings from previous related studies. This result suggests the possibility of social desirability bias in students' responses. (4) Three significant predicator variables contributed to a significant logistic regression equation in which choice of science or mathematics major was the dependent variable: gender (negative association), attitude toward science and math (positive association), and peer influence 1 (positive association). Gender was the strongest predictor. (5) Five significant predictor variables contributed to a significant multiple linear regression equation in which attitude toward science and mathematics was the dependent variable: peer influence 1 (positive association), parent influence 1 (positive association), parent influence 2 (positive association), books in home (positive association), and peer influence 2 (positive association). The results reveal that among the targeted variables (gender, attitude, peer influence 1, peer influence 2, parent influence 1, parent influence 2, books in home, and age) only gender, peer influence 1, and attitude were significant predictors of students' major in math or science.

Integrating black liquor gasification with pulping - Process simulation, economics and potential benefits

NASA Astrophysics Data System (ADS)

Lindstrom, Erik Vilhelm Mathias

Gasification of black liquor could drastically increase the flexibility and improve the profit potential of a mature industry. The completed work was focused on research around the economics and benefits of its implementation, utilizing laboratory pulping experiments and process simulation. The separation of sodium and sulfur achieved through gasification of recovered black liquor, can be utilized in processes like modified continuous cooking, split sulfidity and green liquor pretreatment pulping, and polysulfide-anthraquinone pulping, to improve pulp yield and properties. Laboratory pulping protocols have been developed for these modified pulping technologies and different process options evaluated. The process simulation work around BLG has led to the development of a WinGEMS module for the low temperature MTCI steam reforming process, and case studies comparing a simulated conventional kraft process to different process options built around the implementation of a BLG unit operation into the kraft recovery cycle. Pulp yield increases of 1-3% points with improved product quality, and the potential for capital and operating cost savings relative to the conventional kraft process have been demonstrated. Process simulation work has shown that the net variable operating cost for a pulping process using BLGCC is highly dependent on the cost of lime kiln fuel and the selling price of green power to the grid. Under the assumptions taken in the performed case study, the BLGCC process combined with split sulfidity or PSAQ pulping operations had net variable operating cost 2-4% greater than the kraft reference. The influence of the sales price of power to the grid is the most significant cost factor. If a sales price increase to 6 ¢/KWh for green power could be achieved, cost savings of about $40/ODtP could be realized in all investigated BLG processes. Other alternatives to improve the process economics around BLG would be to modify or eliminate the lime kiln unit operations, utilizing high sulfidity green liquor pretreatment, PSAQ with auto-causticization, or converting the process to mini-sulfide sulfite-AQ.

Influence of a Shorter Duration of Post-Operative Antibiotic Prophylaxis on Infectious Complications in Patients Undergoing Elective Liver Resection.

PubMed

Sakoda, Masahiko; Iino, Satoshi; Mataki, Yuko; Kawasaki, Yota; Kurahara, Hiroshi; Maemura, Kosei; Ueno, Shinichi; Natsugoe, Shoji

Antibiotic prophylaxis has been recommended to reduce post-operative infectious complications. Discontinuation of post-operative antibiotic administration within 24 hours of operation is currently recommended. Many surgeons, however, conventionally tend to extend the duration of prophylactic antibiotic use. In this study, we performed a retrospective analysis to assess the efficacy of extended post-operative antibiotic use in patients who underwent elective liver resection. A total of 208 consecutive patients who underwent liver resection without biliary reconstruction were investigated. Patients were divided into two groups according to the duration of post-operative antibiotic use: Only once after the operation (the post-operative day [POD] 0 group) and until three days after the operation (the POD 3 group). Post-operative complications in the two groups were analyzed and compared. Incisional surgical site infections (SSIs) were observed in 5% of the POD 0 group and 3% of the POD 3 group (p = 0.517). Organ/space SSIs were observed in 2% of the POD 0 group and 3% of the POD 3 group (p = 0.694). Overall infectious complications including SSIs and remote site infections were observed in 12% of the POD 0 group and 11% of the POD 3 group. Multi-variable analyses revealed that the short-term post-operative antibiotic regimen did not confer additional risk for infectious complications. In elective liver resection, the administration of prophylactic antibiotics on the operative day alone appears to be sufficient, because no additional benefit in the incidence of post-operative infectious complications was conferred on patients given antibiotic agents for three days.

A fully associative, nonisothermal, nonlinear kinematic, unified viscoplastic model for titanium alloys

NASA Astrophysics Data System (ADS)

Arnold, S. M.; Saleeb, A. F.; Castelli, M. G.

1995-05-01

Specific forms for both the Gibb's and complementary dissipation potentials are chosen such that a complete (i.e., fully associative) potential base multiaxial, nonisothermal unified viscoplastic model is obtained. This model possesses one tensorial internal state variable (that is, associated with dislocation substructure) and an evolutionary law that has nonlinear kinematic hardening and both thermal and strain induced recovery mechanisms. A unique aspect of the present model is the inclusion of nonlinear hardening through the use of a compliance operator, derived from the Gibb's potential, in the evolution law for the back stress. This nonlinear tensorial operator is significant in that it allows both the flow and evolutionary laws to be fully associative (and therefore easily integrated), greatly influences the multiaxial response under non-proportional loading paths, and in the case of nonisothermal histories, introduces an instantaneous thermal softening mechanism proportional to the rate of change in temperature. In addition to this nonlinear compliance operator, a new consistent, potential preserving, internal strain unloading criterion has been introduced to prevent abnormalities in the predicted stress-strain curves, which are present with nonlinear hardening formulations, during unloading and reversed loading of the external variables. The specific model proposed is characterized for a representative titanium alloy commonly used as the matrix material in SiC fiber reinforced composites, i.e., TIMETAL 21S. Verification of the proposed model is shown using 'specialized' non-standard isothermal and thermomechanical deformation tests.

A fully associative, nonisothermal, nonlinear kinematic, unified viscoplastic model for titanium alloys

NASA Technical Reports Server (NTRS)

Arnold, S. M.; Saleeb, A. F.; Castelli, M. G.

1995-01-01

Specific forms for both the Gibb's and complementary dissipation potentials are chosen such that a complete (i.e., fully associative) potential base multiaxial, nonisothermal unified viscoplastic model is obtained. This model possesses one tensorial internal state variable (that is, associated with dislocation substructure) and an evolutionary law that has nonlinear kinematic hardening and both thermal and strain induced recovery mechanisms. A unique aspect of the present model is the inclusion of nonlinear hardening through the use of a compliance operator, derived from the Gibb's potential, in the evolution law for the back stress. This nonlinear tensorial operator is significant in that it allows both the flow and evolutionary laws to be fully associative (and therefore easily integrated), greatly influences the multiaxial response under non-proportional loading paths, and in the case of nonisothermal histories, introduces an instantaneous thermal softening mechanism proportional to the rate of change in temperature. In addition to this nonlinear compliance operator, a new consistent, potential preserving, internal strain unloading criterion has been introduced to prevent abnormalities in the predicted stress-strain curves, which are present with nonlinear hardening formulations, during unloading and reversed loading of the external variables. The specific model proposed is characterized for a representative titanium alloy commonly used as the matrix material in SiC fiber reinforced composites, i.e., TIMETAL 21S. Verification of the proposed model is shown using 'specialized' non-standard isothermal and thermomechanical deformation tests.

Influence of third molars in Le Fort 1 osteotomy

PubMed Central

Balaji, S. M.

2011-01-01

Background: The influence of maxillary third molar (M3) on the outcomes of Le Fort 1 osteotomy is not deeply investigated. Aim: To investigate the influence of M3 on Le Fort 1 osteotomies. Setting: Tertiary Referral Center, operated by a single surgeon, prospective study. Period: January 2005 to December 2010. Patients: Consecutive Le Fort 1 osteotomy patients with both M3. Predictor Variable: Gender, position, M3 root morphology, and degree of impaction. Outcome Variable: Time taken after all osteotomy cuts to point of time when maxilla is placed in predetermined plane. Result: A total of 658 M3 in line of cut were studied. Of all M3, 312 were impacted, 28.9% were partially impacted and 23.7% were erupted. Of all the M3, 2.9% had their cuspal tips above the horizontal cut, 13.8% along the line of cut, and in 20.7% below the line but not erupted. Buccoverted tooth took shortest time (7.74 minutes), while palatoversion required more time (8.44 minutes) (P = 0.000). When the cuspal tip of M3 was located above the horizontal line of cut, the mean time required to achieve the planned position was 7 minutes, while the completely erupted teeth took a mean of 8.24 minutes (P = 0.000). Conclusion: When the M3 is placed higher, it takes lesser time to prepare basal bone to receive the maxilla at its predetermined level. Angulation of M3 influences the outcome. Deeply placed M3 reduces the manipulation of the greater pterygoid palatine vessels in the area thereby minimizing the bleeding in the surgical field. PMID:23482647

Improving Influence Operations by Defining Influence and Influence Operations

DTIC Science & Technology

2013-12-10

Operations PSYOP Psychological Operations PSYWAR Psychological Warfare SAMS School of Advanced Military Studies SC Strategic Communications USAID...assumed the topic to actually mean what many personnel commonly conceive of as IO or perhaps even so-called strategic communications (SC)? How...affect behaviors, protect operations, communicate commander’s intent, and project accurate information to achieve desired effects across the cognitive

Usage of Neural Network to Predict Aluminium Oxide Layer Thickness

PubMed Central

Michal, Peter; Vagaská, Alena; Gombár, Miroslav; Kmec, Ján; Spišák, Emil; Kučerka, Daniel

2015-01-01

This paper shows an influence of chemical composition of used electrolyte, such as amount of sulphuric acid in electrolyte, amount of aluminium cations in electrolyte and amount of oxalic acid in electrolyte, and operating parameters of process of anodic oxidation of aluminium such as the temperature of electrolyte, anodizing time, and voltage applied during anodizing process. The paper shows the influence of those parameters on the resulting thickness of aluminium oxide layer. The impact of these variables is shown by using central composite design of experiment for six factors (amount of sulphuric acid, amount of oxalic acid, amount of aluminium cations, electrolyte temperature, anodizing time, and applied voltage) and by usage of the cubic neural unit with Levenberg-Marquardt algorithm during the results evaluation. The paper also deals with current densities of 1 A·dm−2 and 3 A·dm−2 for creating aluminium oxide layer. PMID:25922850

A preliminary analysis of human factors affecting the recognition accuracy of a discrete word recognizer for C3 systems

NASA Astrophysics Data System (ADS)

Yellen, H. W.

1983-03-01

Literature pertaining to Voice Recognition abounds with information relevant to the assessment of transitory speech recognition devices. In the past, engineering requirements have dictated the path this technology followed. But, other factors do exist that influence recognition accuracy. This thesis explores the impact of Human Factors on the successful recognition of speech, principally addressing the differences or variability among users. A Threshold Technology T-600 was used for a 100 utterance vocubalary to test 44 subjects. A statistical analysis was conducted on 5 generic categories of Human Factors: Occupational, Operational, Psychological, Physiological and Personal. How the equipment is trained and the experience level of the speaker were found to be key characteristics influencing recognition accuracy. To a lesser extent computer experience, time or week, accent, vital capacity and rate of air flow, speaker cooperativeness and anxiety were found to affect overall error rates.

The influence of biological sex, sexuality and gender role on interpersonal distance.

PubMed

Uzzell, David; Horne, Nathalie

2006-09-01

This research reports on a conceptually and methodologically innovative study, which sought to measure the influence of gender on interpersonal distance. In so doing, we argue for an important distinction to be made between biological sex, gender role, and sexuality. To date, however, progress in the study of interpersonal distance (IPD) has been inhibited by poor operational definitions and inadequate measurement methodologies. For our own investigation, we innovated on methodology by devising the digital video-recording IPD method (DiVRID) that records interpersonal spatial relationships using high quality digital video equipment. The findings highlighted not only the validity of our innovative method of investigation, but also that a more sophisticated conceptualization of the impact of gender on IPD is warranted than can be accounted for by biological sex differences. In this study, we found that gender role accounts for more of the variation in IPD than the conventionally reported gender variable, sex.

Study of blades inclination influence of gate impeller with a non-Newtonian fluid of Bingham

NASA Astrophysics Data System (ADS)

Rahmani, Lakhdar; Seghier, O.; Draoui, B.; Benachour, E.

2016-03-01

A large number of chemical operations, biochemical or petrochemical industry is very depending on the rheological fluids nature. In this work, we study the case of highly viscous of viscoplastic fluids in a classical system of agitation: a cylindrical tank with plate bottom without obstacles agitated by gate impeller agitator. We are interested to the laminar, incompressible and isothermal flows. We devote to a numerical approach carried out using an industrial code CFD Fluent 6.3.26 based on the method of finites volumes discretization of Navier - Stokes equations formulated in variables (U.V.P). The threshold of flow related to the viscoplastic behavior is modeled by a theoretical law of Bingham. The results obtained are used to compare between the five configurations suggested of power consumption. We study the influence of inertia by the variation of Reynolds number.

Usage of neural network to predict aluminium oxide layer thickness.

PubMed

Michal, Peter; Vagaská, Alena; Gombár, Miroslav; Kmec, Ján; Spišák, Emil; Kučerka, Daniel

2015-01-01

This paper shows an influence of chemical composition of used electrolyte, such as amount of sulphuric acid in electrolyte, amount of aluminium cations in electrolyte and amount of oxalic acid in electrolyte, and operating parameters of process of anodic oxidation of aluminium such as the temperature of electrolyte, anodizing time, and voltage applied during anodizing process. The paper shows the influence of those parameters on the resulting thickness of aluminium oxide layer. The impact of these variables is shown by using central composite design of experiment for six factors (amount of sulphuric acid, amount of oxalic acid, amount of aluminium cations, electrolyte temperature, anodizing time, and applied voltage) and by usage of the cubic neural unit with Levenberg-Marquardt algorithm during the results evaluation. The paper also deals with current densities of 1 A · dm(-2) and 3 A · dm(-2) for creating aluminium oxide layer.

Stochastic Watershed Models for Risk Based Decision Making

NASA Astrophysics Data System (ADS)

Vogel, R. M.

2017-12-01

Over half a century ago, the Harvard Water Program introduced the field of operational or synthetic hydrology providing stochastic streamflow models (SSMs), which could generate ensembles of synthetic streamflow traces useful for hydrologic risk management. The application of SSMs, based on streamflow observations alone, revolutionized water resources planning activities, yet has fallen out of favor due, in part, to their inability to account for the now nearly ubiquitous anthropogenic influences on streamflow. This commentary advances the modern equivalent of SSMs, termed `stochastic watershed models' (SWMs) useful as input to nearly all modern risk based water resource decision making approaches. SWMs are deterministic watershed models implemented using stochastic meteorological series, model parameters and model errors, to generate ensembles of streamflow traces that represent the variability in possible future streamflows. SWMs combine deterministic watershed models, which are ideally suited to accounting for anthropogenic influences, with recent developments in uncertainty analysis and principles of stochastic simulation

Analysis of the Effects of a Flexible Ramping Ancillary Service Product on Power System Operations: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krad, Ibrahim; Ibanez, Eduardo; Ela, Erik

2015-10-19

The recent increased interest in utilizing variable generation (VG) resources such as wind and solar in power systems has motivated investigations into new operating procedures. Although these resources provide desirable value to a system (e.g., no fuel costs or emissions), interconnecting them provides unique challenges. Their variable, non-controllable nature in particular requires significant attention, because it directly results in increased power system variability and uncertainty. One way to handle this is via new operating reserve schemes. Operating reserves provide upward and downward generation and ramping capacity to counteract uncertainty and variability prior to their realization. For instance, uncertainty and variabilitymore » in real-time dispatch can be accounted for in the hour-ahead unit commitment. New operating reserve methodologies that specifically account for the increased variability and uncertainty caused by VG are currently being investigated and developed by academia and industry. This paper examines one method inspired by the new operating reserve product being proposed by the California Independent System Operator. The method is based on examining the potential ramping requirements at any given time and enforcing those requirements via a reserve demand curve in the market-clearing optimization as an additional ancillary service product.« less

Natural and management influences on freshwater inflows and salinity in the San Francisco Estuary at monthly to interannual scales

USGS Publications Warehouse

Knowles, Noah

2002-01-01

Understanding the processes controlling the physics, chemistry, and biology of the San Francisco Estuary and their relation to climate variability is complicated by the combined influence on freshwater inflows of natural variability and upstream management. To distinguish these influences, alterations of estuarine inflow due to major reservoirs and freshwater pumping in the watershed were inferred from available data. Effects on salinity were estimated by using reconstructed estuarine inflows corresponding to differing levels of impairment to drive a numerical salinity model. Both natural and management inflow and salinity signals show strong interannual variability. Management effects raise salinities during the wet season, with maximum influence in spring. While year‐to‐year variations in all signals are very large, natural interannual variability can greatly exceed the range of management effects on salinity in the estuary.

[Coronary artery bypass surgery: methods of performance monitoring and quality control].

PubMed

Albert, A; Sergeant, P; Ennker, J

2009-10-01

The strength of coronary bypass operations depends on the preservation of their benefits regarding freedom of symptoms, quality of life and survival, over decades. Significant variability of the results of an operative intervention according to the hospital or the operating surgeon is considered a weakness in the procedure. The external quality insurance tries to reach a transparent service providing market through hospital ranking comparability. Widely available information and competition will promote the improvement of the whole quality. The structured dialog acts as a control instrument for the BQS (Federal Quality Insurance). It is launched in case of deviations from the standard references or statistically significant differences between the results of the operations in any hospital and the average notational results. In comparison to the external control the hospital internal control has greater ability to reach a medically useful statement regarding the results of the treatment and to correct the mistakes in time. An online information portal based on a departmental databank (DataWarehouse, DataMart) is an attractive solution for the physician in order to get transparently and timely informed about the variability in the performance.The individual surgeon significantly influences the short- and long-term treatment results. Accordingly, selection, targeted training and performance measurements are necessary.Strict risk management and failure analysis of individual cases are included in the methods of internal quality control aiming to identify and correct the inadequacies in the system and the course of treatment. According to the international as well as our own experience, at least 30% of the mortalities after bypass operations are avoidable. A functioning quality control is especially important in minimally invasive interventions because they are often technically more demanding in comparison to the conventional procedures. In the field of OPCAB surgery, the special advantages of the procedure can be utilised to reach a nearly complete avoidance of postoperative stroke through combining the procedure with aorta no-touch technique. The long-term success of the bypass operation depends on the type of bypass material in additions to many other factors. Both internal mammary arteries are considered the most durable.Using an operation preparation check contributes to the operative success.

Familial influences on the full range of variability in attention and activity levels during adolescence: A longitudinal twin study.

PubMed

Peng, Chun-Zi; Grant, Julia D; Heath, Andrew C; Reiersen, Angela M; Mulligan, Richard C; Anokhin, Andrey P

2016-05-01

To investigate familial influences on the full range of variability in attention and activity across adolescence, we collected maternal ratings of 339 twin pairs at ages 12, 14, and 16, and estimated the transmitted and new familial influences on attention and activity as measured by the Strengths and Weaknesses of Attention-Deficit/Hyperactivity Disorder Symptoms and Normal Behavior Scale. Familial influences were substantial for both traits across adolescence: genetic influences accounted for 54%-73% (attention) and 31%-73% (activity) of the total variance, and shared environmental influences accounted for 0%-22% of the attention variance and 13%-57% of the activity variance. The longitudinal stability of individual differences in attention and activity was largely accounted for by familial influences transmitted from previous ages. Innovations over adolescence were also partially attributable to familial influences. Studying the full range of variability in attention and activity may facilitate our understanding of attention-deficit/hyperactivity disorder's etiology and intervention.

The Effect of Antifibrinolytic Prophylaxis on Postoperative Outcomes in Patients Undergoing Cardiac Operations

PubMed Central

Koul, Abhinav; Ferraris, Victor; Davenport, Daniel L; Ramaiah, Chandrashekhar

2012-01-01

Antifibrinolytic agents such as aprotinin and epsilon aminocaproic acid limit postoperative bleeding and blood transfusion in patients undergoing cardiac operations using cardiopulmonary bypass (CPB). Recent evidence suggests that these agents have adverse side effects that influence operative mortality and morbidity. We studied postoperative bleeding, transfusion rates, and operative outcomes in our patients in order to assess the efficacy of these agents during cardiac operations requiring CPB. We reviewed records of 520 patients undergoing a variety of cardiac operations between January 2005 and May 2009. We measured multiple variables including pre-operative risk factors, antifibrinolytic agent used, and outcomes of operation, such as measures of bleeding and blood transfusion, as well as serious operative morbidity and mortality. Postoperative bleeding rates varied significantly between patients receiving aprotinin and those receiving aminocaproic acid (P < 0.05). There was an associated 12% decrease in operative site bleeding in aprotinin-treated patients compared with aminocaproic acid. There was no significant difference in the transfusion rates of packed red blood cells between patients receiving aminocaproic acid or aprotinin (P > 0.05), though individuals in the aprotinin group did receive FFP more frequently than patients in the aminocaproic acid group (P < 0.05). There was no significant difference in morbidity and mortality rates between patients in either drug group (P > 0.05). Our study shows that aprotinin is more effective at controlling operative site bleeding than aminocaproic acid. Reduced operative site bleeding did not portend better outcome or differences in transfusion requirements. Aminocaproic acid remains a safe and cost-effective option for antifibrinolytic prophylaxis because of unavailability of aprotinin. PMID:23101999

Statistical Exposé of a Multiple-Compartment Anaerobic Reactor Treating Domestic Wastewater.

PubMed

Pfluger, Andrew R; Hahn, Martha J; Hering, Amanda S; Munakata-Marr, Junko; Figueroa, Linda

2018-06-01

  Mainstream anaerobic treatment of domestic wastewater is a promising energy-generating treatment strategy; however, such reactors operated in colder regions are not well characterized. Performance data from a pilot-scale, multiple-compartment anaerobic reactor taken over 786 days were subjected to comprehensive statistical analyses. Results suggest that chemical oxygen demand (COD) was a poor proxy for organics in anaerobic systems as oxygen demand from dissolved inorganic material, dissolved methane, and colloidal material influence dissolved and particulate COD measurements. Additionally, univariate and functional boxplots were useful in visualizing variability in contaminant concentrations and identifying statistical outliers. Further, significantly different dissolved organic removal and methane production was observed between operational years, suggesting that anaerobic reactor systems may not achieve steady-state performance within one year. Last, modeling multiple-compartment reactor systems will require data collected over at least two years to capture seasonal variations of the major anaerobic microbial functions occurring within each reactor compartment.

Putting a price tag on novel autologous cellular therapies.

PubMed

Abou-El-Enein, Mohamed; Bauer, Gerhard; Medcalf, Nicholas; Volk, Hans-Dieter; Reinke, Petra

2016-08-01

Cell therapies, especially autologous therapies, pose significant challenges to researchers who wish to move from small, probably academic, methods of manufacture to full commercial scale. There is a dearth of reliable information about the costs of operation, and this makes it difficult to predict with confidence the investment needed to translate the innovations to the clinic, other than as small-scale, clinician-led prescriptions. Here, we provide an example of the results of a cost model that takes into account the fixed and variable costs of manufacture of one such therapy. We also highlight the different factors that influence the product final pricing strategy. Our findings illustrate the need for cooperative and collective action by the research community in pre-competitive research to generate the operational models that are much needed to increase confidence in process development for these advanced products. Copyright © 2016 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

Automations influence on nuclear power plants: a look at three accidents and how automation played a role.

PubMed

Schmitt, Kara

2012-01-01

Nuclear power is one of the ways that we can design an efficient sustainable future. Automation is the primary system used to assist operators in the task of monitoring and controlling nuclear power plants (NPP). Automation performs tasks such as assessing the status of the plant's operations as well as making real time life critical situational specific decisions. While the advantages and disadvantages of automation are well studied in variety of domains, accidents remind us that there is still vulnerability to unknown variables. This paper will look at the effects of automation within three NPP accidents and incidents and will consider why automation failed in preventing these accidents from occurring. It will also review the accidents at the Three Mile Island, Chernobyl, and Fukushima Daiichi NPP's in order to determine where better use of automation could have resulted in a more desirable outcome.

Factors affecting the labor efficiency of hospital-based blood bank laboratories.

PubMed

Lam, H C; Kominski, G F; Petz, L D; Sofaer, S

1994-09-01

A variety of financing mechanisms and managerial innovations have been developed in the past decade to control hospital costs. Some evidence suggests that those changes have not produced substantial improvements in labor efficiency among employees in the hospital's technical level, such as in the blood bank laboratories. This study measured labor efficiency in 40 hospital-based blood bank laboratories in Southern California during the year from July 1989 to June 1990 and explored the impact of financial, managerial, and operational factors on labor efficiency. With standardized output measures used in all blood bank laboratories, a wide variation of labor efficiency was found. Multivariate analyses indicate that the labor efficiency of blood bank employees was not influenced by organizational financial incentives, but was affected by the managerial styles of blood bank managers. Interpretation of the findings suggests that labor efficiency is affected by operational designs intended to improve responses to variable workloads and reduce slack time.

Technical specifications of low-frequency radio identification bedload tracking from field experiments: Differences in antennas, tags and operators

NASA Astrophysics Data System (ADS)

Arnaud, F.; Piégay, H.; Vaudor, L.; Bultingaire, L.; Fantino, G.

2015-06-01

Low-frequency passive integrated transponders (PIT tags) have been increasingly used for tracking bedload transport in gravel-bed rivers. Prior studies have reported high recovery rates in small streams, while recovery rates remained much lower in large systems, in large part because of the limited reading distance of the tags (< 1 m). Some laboratory tests have identified controlling factors for detection ranges (tag and antenna size, tag orientation, burial, submergence, etc.). Beyond these tests, improving our understanding of PIT tag functioning, using different equipment within different environments, is still needed in order to select the most suitable device for each geomorphic context. We address this knowledge gap with technical specifications for a low-frequency radio identification (RFID) device by working for the first time with real fluvial constraints, i.e., the gravel deposits and the aquatic channel. The three-dimensional detection envelopes of two types of tags and three types of antennas are quantified as well as the effect of practices (interoperator bias, battery power) on the detection. The interoperator variability and the intertag variability can be considered as negligible. The influence of burial in dry and water-saturated sediment and the influence of water immersion are shown to be minor. Finally, we summarize practical implications for RFID bedload tracking through these experiments.

US residential building air exchange rates: new perspectives to improve decision making at vapor intrusion sites.

PubMed

Reichman, Rivka; Shirazi, Elham; Colliver, Donald G; Pennell, Kelly G

2017-02-22

Vapor intrusion (VI) is well-known to be difficult to characterize because indoor air (IA) concentrations exhibit considerable temporal and spatial variability in homes throughout impacted communities. To overcome this and other limitations, most VI science has focused on subsurface processes; however there is a need to understand the role of aboveground processes, especially building operation, in the context of VI exposure risks. This tutorial review focuses on building air exchange rates (AERs) and provides a review of literature related building AERs to inform decision making at VI sites. Commonly referenced AER values used by VI regulators and practitioners do not account for the variability in AER values that have been published in indoor air quality studies. The information presented herein highlights that seasonal differences, short-term weather conditions, home age and air conditioning status, which are well known to influence AERs, are also likely to influence IA concentrations at VI sites. Results of a 3D VI model in combination with relevant AER values reveal that IA concentrations can vary more than one order of magnitude due to air conditioning status and one order of magnitude due to house age. Collectively, the data presented strongly support the need to consider AERs when making decisions at VI sites.

The influence of dispositional optimism on decision regret to undergo major breast reconstructive surgery.

PubMed

Zhong, Toni; Bagher, Shaghayegh; Jindal, Kunaal; Zeng, Delong; O'Neill, Anne C; MacAdam, Sheina; Butler, Kate; Hofer, Stefan O P; Pusic, Andrea; Metcalfe, Kelly A

2013-12-01

It is not known if optimism influences regret following major reconstructive breast surgery. We examined the relationship between dispositional optimism, major complications and decision regret in patients undergoing microsurgical breast reconstruction. A consecutive series of 290 patients were surveyed. Independent variables were: (1) dispositional optimism and (2) major complications. The primary outcome was Decision Regret. A multivariate regression analysis determined the relationship between the independent variables, confounders and decision regret. Of the 181 respondents, 63% reported no regret after breast reconstruction, 26% had mild regret, and 11% moderate to severe regret. Major complications did not have a significant effect on decision regret, and the impact of dispositional optimism was not significant in Caucasian women. There was a significant effect in non-Caucasian women with less optimism who had significantly higher levels of mild regret 1.36 (CI 1.02-1.97) and moderate to severe regret 1.64 (CI 1.0-93.87). This is the first paper to identify a subgroup of non-Caucasian patients with low dispositional optimism who may be at risk for developing regret after microsurgical breast reconstruction. Possible strategies to ameliorate regret may involve addressing cultural and language barriers, setting realistic expectations, and providing more support during the pre-operative decision-making phase. © 2013 Wiley Periodicals, Inc.

Combining Variables, Controlling Variables, and Proportions: Is There a Psychological Link?

ERIC Educational Resources Information Center

Lawson, Anton E.

1979-01-01

Investigated the degree of relationship among the performance of 28 seventh grade students on the following three formal operations tasks: chemical combinations, bending rods, and balance beam. Results show that task performance ranged widely from early concrete operational to fully operational. (HM)

Within and between Individual Variability of Exposure to Work-Related Musculoskeletal Disorder Risk Factors.

PubMed

Zare, Mohsen; Sagot, Jean-Claude; Roquelaure, Yves

2018-05-17

Industrial companies indicate a tendency to eliminate variations in operator strategies, particularly following implementation of the lean principle. Companies believe when the operators perform the same prescribed tasks, they have to execute them in the same manner (completing the same gestures and being exposed to the same risk factors). They attempt to achieve better product quality by standardizing and reducing operational leeway. However, operators adjust and modify ways of performing tasks to balance between their abilities and the requirements of the job. This study aims to investigate the variability of exposure to physical risk factors within and between operators when executing the same prescribed tasks. The Ergonomic Standard method was used to evaluate two workstations. Seven operators were observed thirty times between repeated cycle times at those workstations. The results revealed the variability of exposure to risk factors between and within operators in the repeated execution of the same tasks. Individual characteristics and operators' strategies might generate the variability of exposure to risk factors that may be an opportunity to reduce the risks of work-related musculoskeletal disorders (WR-MSDs). However, sometimes operators' strategies may cause overexposure to risk factors; operators most often adopt such strategies to undertake their tasks while reducing the workload.

CURRENT CONCEPTS ON THE GENETIC FACTORS IN ROTATOR CUFF PATHOLOGY AND FUTURE IMPLICATIONS FOR SPORTS PHYSICAL THERAPISTS

PubMed Central

Paré, Jessica; Froehlich, John E

2017-01-01

Context Recent advances within the field of genetics are currently changing many of the methodologies in which medicine is practiced. These advances are also beginning to influence the manner in which physical therapy services are rendered. Rotator cuff pathology is one of the most common diagnoses treated by the sports physical therapist. The purpose of this commentary is to educate sports physical therapists on the recent advances regarding how genetics influences rotator cuff pathology, including rotator cuff tears, and provide a perspective on how this information will likely influence post-operative shoulder rehabilitation in the near future. Evidence Acquisition A comprehensive review of the literature was completed using the Medline database along with individual searches of relevant physical therapy, surgical, cell biology, and sports medicine journals. Search terms included: shoulder, rotator cuff pathology, genetics, apoptosis, and physical therapy. Search results were compiled and evaluated; relevant primary studies and review articles were gathered; the results from this comprehensive review are summarized here. Study Design Clinical Commentary, Review of the Literature Results Recent advances within the understanding of rotator cuff pathology have further elucidated the cellular and molecular mechanisms associated with rotator cuff tears. There appears to be a hypoxic-induced apoptotic cellular pathway that contributes to rotator cuff tears. Activation of specific proteins termed matrix metalloproteinases appear to be involved in not only primary rotator cuff tears, but also may influence the re-tear rate after surgical intervention. Further advancements in the understanding of the cellular mechanisms contributing to rotator cuff tears and postoperative techniques to help prevent re-tears, may soon influence the methodology in which physical therapy services are provided to patients sustaining a rotator cuff injury. Conclusions At this time continued research is required to more fully develop a comprehensive understanding of the role of genetic variables both within primary rotator cuff tears and their influences on post-operative rehabilitation from rotator cuff repair surgery. Level of Evidence Level 5 PMID:28515982

An experimental study of fuel injection strategies in CAI gasoline engine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hunicz, J.; Kordos, P.

2011-01-15

Combustion of gasoline in a direct injection controlled auto-ignition (CAI) single-cylinder research engine was studied. CAI operation was achieved with the use of the negative valve overlap (NVO) technique and internal exhaust gas re-circulation (EGR). Experiments were performed at single injection and split injection, where some amount of fuel was injected close to top dead centre (TDC) during NVO interval, and the second injection was applied with variable timing. Additionally, combustion at variable fuel-rail pressure was examined. Investigation showed that at fuel injection into recompressed exhaust fuel reforming took place. This process was identified via an analysis of the exhaust-fuelmore » mixture composition after NVO interval. It was found that at single fuel injection in NVO phase, its advance determined the heat release rate and auto-ignition timing, and had a strong influence on NO{sub X} emission. However, a delay of single injection to intake stroke resulted in deterioration of cycle-to-cycle variability. Application of split injection showed benefits of this strategy versus single injection. Examinations of different fuel mass split ratios and variable second injection timing resulted in further optimisation of mixture formation. At equal share of the fuel mass injected in the first injection during NVO and in the second injection at the beginning of compression, the lowest emission level and cyclic variability improvement were observed. (author)« less

Basic principles of variable speed drives

NASA Technical Reports Server (NTRS)

Loewenthal, S. H.

1973-01-01

An understanding of the principles which govern variable speed drive operation is discussed for successful drive application. The fundamental factors of torque, speed ratio, and power as they relate to drive selection are discussed. The basic types of variable speed drives, their operating characteristics and their applications are also presented.

Utility of mesohabitat features for determining habitat associations of subadult sharks in Georgia’s estuaries

USGS Publications Warehouse

Belcher, C.N.; Jennings, Cecil A.

2010-01-01

We examined the affects of selected water quality variables on the presence of subadult sharks in six of nine Georgia estuaries. During 231 longline sets, we captured 415 individuals representing nine species. Atlantic sharpnose shark (Rhizoprionodon terranovae), bonnethead (Sphyrna tiburo), blacktip shark (Carcharhinus limbatus) and sandbar shark (C. plumbeus) comprised 96.1% of the catch. Canonical correlation analysis (CCA) was used to assess environmental influences on the assemblage of the four common species. Results of the CCA indicated Bonnethead Shark and Sandbar Shark were correlated with each other and with a subset of environmental variables. When the species occurred singly, depth was the defining environmental variable; whereas, when the two co-occurred, dissolved oxygen and salinity were the defining variables. Discriminant analyses (DA) were used to assess environmental influences on individual species. Results of the discriminant analyses supported the general CCA findings that the presence of bonnethead and sandbar shark were the only two species that correlated with environmental variables. In addition to depth and dissolved oxygen, turbidity influenced the presence of sandbar shark. The presence of bonnethead shark was influenced primarily by salinity and turbidity. Significant relationships existed for both the CCA and DA analyses; however, environmental variables accounted for <16% of the total variation in each. Compared to the environmental variables we measured, macrohabitat features (e.g., substrate type), prey availability, and susceptibility to predation may have stronger influences on the presence and distribution of subadult shark species among sites.

Thermoelectric power generator for variable thermal power source

DOEpatents

Bell, Lon E; Crane, Douglas Todd

2015-04-14

Traditional power generation systems using thermoelectric power generators are designed to operate most efficiently for a single operating condition. The present invention provides a power generation system in which the characteristics of the thermoelectrics, the flow of the thermal power, and the operational characteristics of the power generator are monitored and controlled such that higher operation efficiencies and/or higher output powers can be maintained with variably thermal power input. Such a system is particularly beneficial in variable thermal power source systems, such as recovering power from the waste heat generated in the exhaust of combustion engines.

Survival of white-tailed deer neonates in Minnesota and South Dakota

USGS Publications Warehouse

Grovenburg, T.W.; Swanson, C.C.; Jacques, C.N.; Klaver, R.W.; Brinkman, T.J.; Burris, B.M.; Deperno, C.S.; Jenks, J.A.

2011-01-01

Understanding the influence of intrinsic (e.g., age, birth mass, and sex) and habitat factors on survival of neonate white-tailed deer improves understanding of population ecology. During 2002–2004, we captured and radiocollared 78 neonates in eastern South Dakota and southwestern Minnesota, of which 16 died before 1 September. Predation accounted for 80% of mortality; the remaining 20% was attributed to starvation. Canids (coyotes [Canis latrans], domestic dogs) accounted for 100% of predation on neonates. We used known fate analysis in Program MARK to estimate survival rates and investigate the influence of intrinsic and habitat variables on survival. We developed 2 a priori model sets, including intrinsic variables (model set 1) and habitat variables (model set 2; forested cover, wetlands, grasslands, and croplands). For model set 1, model {Sage-interval} had the lowest AICc (Akaike's information criterion for small sample size) value, indicating that age at mortality (3-stage age-interval: 0–2 weeks, 2–8 weeks, and >8 weeks) best explained survival. Model set 2 indicated that habitat variables did not further influence survival in the study area; β-estimates and 95% confidence intervals for habitat variables in competing models encompassed zero; thus, we excluded these models from consideration. Overall survival rate using model {Sage-interval} was 0.87 (95% CI = 0.83–0.91); 61% of mortalities occurred at 0–2 weeks of age, 26% at 2–8 weeks of age, and 13% at >8 weeks of age. Our results indicate that variables influencing survival may be area specific. Region-specific data are needed to determine influences of intrinsic and habitat variables on neonate survival before wildlife managers can determine which habitat management activities influence neonate populations.

The influence of carrier dynamics on double-state lasing in quantum dot lasers at variable temperature

NASA Astrophysics Data System (ADS)

Korenev, V. V.; Savelyev, A. V.; Zhukov, A. E.; Omelchenko, A. V.; Maximov, M. V.

2014-12-01

It is shown in analytical form that the carrier capture from the matrix as well as carrier dynamics in quantum dots plays an important role in double-state lasing phenomenon. In particular, the de-synchronization of hole and electron captures allows one to describe recently observed quenching of ground-state lasing, which takes place in quantum dot lasers operating in double-state lasing regime at high injection. From the other side, the detailed analysis of charge carrier dynamics in the single quantum dot enables one to describe the observed light-current characteristics and key temperature dependences.

PVD thermal barrier coating applications and process development for aircraft engines

NASA Astrophysics Data System (ADS)

Rigney, D. V.; Viguie, R.; Wortman, D. J.; Skelly, D. W.

1997-06-01

Thermal barrier coatings (TBCs) have been developed for application to aircraft engine components to improve service life in an increasingly hostile thermal environment. The choice of TBC type is related to the component, intended use, and economics. Selection of electron beam physical vapor deposition proc-essing for turbine blade is due in part to part size, surface finish requirements, thickness control needs, and hole closure issues. Process development of PVD TBCs has been carried out at several different sites, including GE Aircraft Engines (GEAE). The influence of processing variables on microstructure is dis-cussed, along with the GEAE development coater and initial experiences of pilot line operation.

Effects of situational conditions on students' views of business ethics.

PubMed

Matsui, Tamao; Kakuyama, Takashi; Tsuzuki, Yukie

2003-12-01

This study investigated undergraduates' responses regarding selected ethical issues facing managers and employees of today's businesses. The focus of the study lies in the influences of two situational variables (organizational roles and prospects) on students' response pattern. Japanese students (306 men and 81 women, M = 20.1 yr., SD = 2.2) imagined that they were managers or operative employees of a middle-sized manufacturing company and that their company had high or low prospects. The response pattern tended to be more ethical for "managers," whereas the response pattern tended to be less ethical for "employees" in a "low prospect" than in a "high prospect" company.

Comparison of polynomial and neural fuzzy models as applied to the ethanolamine pulping of vine shoots.

PubMed

Jiménez, L; Angulo, V; Caparrós, S; Ariza, J

2007-12-01

The influence of operational variables in the pulping of vine shoots by use of ethanolamine [viz. temperature (155-185 degrees C), cooking time (30-90min) and ethanolamine concentration (50-70% v/v)] on the properties of the resulting pulp (viz. yield, kappa index, viscosity and drainability) was studied. A central composite factorial design was used in conjunction with the software BMDP and ANFIS Edit Matlab 6.5 to develop polynomial and fuzzy neural models that reproduced the experimental results of the dependent variables with errors less than 10%. Both types of models are therefore effective with a view to simulating the ethanolamine pulping process. Based on the proposed equations, the best choice is to use values of the operational valuables resulting in near-optimal pulp properties while saving energy and immobilized capital on industrial facilities by using lower temperatures and shorter processing times. One combination leading to near-optimal properties with reduced costs is using a temperature of 180 degrees C and an ethanolamine concentration of 60% for 60min, to obtain pulp with a viscosity of 6.13% lower than the maximum value (932.8ml/g) and a drainability of 5.49% lower than the maximum value (71 (o)SR).

An Attempt at Quantifying Factors that Affect Efficiency in the Management of Solid Waste Produced by Commercial Businesses in the City of Tshwane, South Africa

PubMed Central

Worku, Yohannes; Muchie, Mammo

2012-01-01

Objective. The objective was to investigate factors that affect the efficient management of solid waste produced by commercial businesses operating in the city of Pretoria, South Africa. Methods. Data was gathered from 1,034 businesses. Efficiency in solid waste management was assessed by using a structural time-based model designed for evaluating efficiency as a function of the length of time required to manage waste. Data analysis was performed using statistical procedures such as frequency tables, Pearson's chi-square tests of association, and binary logistic regression analysis. Odds ratios estimated from logistic regression analysis were used for identifying key factors that affect efficiency in the proper disposal of waste. Results. The study showed that 857 of the 1,034 businesses selected for the study (83%) were found to be efficient enough with regards to the proper collection and disposal of solid waste. Based on odds ratios estimated from binary logistic regression analysis, efficiency in the proper management of solid waste was significantly influenced by 4 predictor variables. These 4 influential predictor variables are lack of adherence to waste management regulations, wrong perception, failure to provide customers with enough trash cans, and operation of businesses by employed managers, in a decreasing order of importance. PMID:23209483

Impact of the operation of cascade reservoirs in upper Yangtze River on hydrological variability of the mainstream

NASA Astrophysics Data System (ADS)

Changjiang, Xu; Dongdong, Zhang

2018-06-01

As the impacts by climate changes and human activities are intensified, variability may occur in river's annual runoff as well as flood and low water characteristics. In order to understand the characteristics of variability in hydrological series, diagnosis and identification must be conducted specific to the variability of hydrological series, i.e., whether there was variability and where the variability began to occur. In this paper, the mainstream of Yangtze River was taken as the object of study. A model was established to simulate the impounding and operation of upstream cascade reservoirs so as to obtain the runoff of downstream hydrological control stations after the regulation by upstream reservoirs in different level years. The Range of Variability Approach was utilized to analyze the impact of the operation of upstream reservoirs on the variability of downstream. The results indicated that the overall hydrologic alterations of Yichang hydrological station in 2010 level year, 2015 level year and the forward level year were 68.4, 72.5 and 74.3 % respectively, belonging to high alteration in all three level years. The runoff series of mainstream hydrological stations presented variability in different degrees, where the runoff series of the four hydrological stations including Xiangjiaba, Gaochang and Wulong belonged to high alteration in the three level years; and the runoff series of Beibei hydrological station in 2010 level year belonged to medium alteration, and high alteration in 2015 level year and the forward level year. The study on the impact of the operation of cascade reservoirs in Upper Yangtze River on hydrological variability of the mainstream had important practical significance on the sustainable utilization of water resources, disaster prevention and mitigation, safe and efficient operation and management of water conservancy projects and stable development of the economic society.

Importance-Performance Matrix Analysis (IPMA) Of Transport Disadvantage Variables on Social Exclusion in a Rural Context

NASA Astrophysics Data System (ADS)

Larasati, Ophilia; Puspita Dirgahayani, Eng., Dr.

2018-05-01

Transport services are essential to support daily life. A lack of transport supply leads to the existence of transport disadvantaged (TDA) groups who are vulnerable to social exclusion, which happens when a particular group or individual is having difficulties to access certain activities that are considered normal in society. To tackle this phenomenon, the understanding of the influence of TDA variables on social exclusion is needed. The aim of this study is to analyze the influences of TDA variables on social exclusion in a rural context, with Cibeureum Village (Bandung Barat Regency) and Bunikasih Village (Subang Regency) as the study case. Both case studies provide different characteristics of accessibility. Partial Least Squares (PLS) Structural Equation Modeling (SEM) is chosen as the method to analyze the influences of TDA variables on social exclusion. The PLS-SEM model is developed according to the social exclusion variable and four TDA variables, i.e., accessibility, individual characteristics, private vehicle existence, and travel behavior. IPMA is done after the PLS-SEM model is evaluated. The study reveals that among four of the TDA variables, accessibility has the most influence on social exclusion, hence interventions related to improving accessibility are needed to tackle social exclusion. More specifically, the provision of alternative modes is needed in both study areas, while in Bunikasih Village the cost of travel is also an important variable to consider.

Physician Impact on the Total Cost of Care

PubMed Central

Taheri, Paul A.; Butz, David; Griffes, Louisa C.; Morlock, David R.; Greenfield, Lazar J.

2000-01-01

Background and Objectives Physicians’ efforts at cost containment focus on decreased resource utilization and reduced length of stay. Although these efforts appear to be appropriate, little data exist to gauge their success. As such, the goal of this study is to determine trauma service cost allocations and how this information can help physicians to contain costs. Materials and Methods The authors analyzed the costs for 696 trauma admissions at a level I trauma center for fiscal year 1997. Data were obtained from the hospital costing system. Costs analyzed were variable direct, fixed direct, and Indirect costs. Together, the fixed and indirect costs are referred to as “hospital overhead.” Total Cost equals variable direct plus fixed direct plus indirect costs. Results The mean variable, fixed, and indirect costs per patient were $7,998, $3,534, and $11,086, respectively. Mean total cost per patient was $22,618. Conclusion The 35% variable direct cost represents the percentage of total cost that is typically under the immediate influence of physicians, in contrast to the 65% of total cost over which physicians have little control. Physicians must gain a better understanding of cost drivers and must participate in the operations and allocations of institutional fixed direct and indirect costs if the overall cost of care is to be reduced. PMID:10714637

Simple Sensitivity Analysis for Orion GNC

NASA Technical Reports Server (NTRS)

Pressburger, Tom; Hoelscher, Brian; Martin, Rodney; Sricharan, Kumar

2013-01-01

The performance of Orion flight software, especially its GNC software, is being analyzed by running Monte Carlo simulations of Orion spacecraft flights. The simulated performance is analyzed for conformance with flight requirements, expressed as performance constraints. Flight requirements include guidance (e.g. touchdown distance from target) and control (e.g., control saturation) as well as performance (e.g., heat load constraints). The Monte Carlo simulations disperse hundreds of simulation input variables, for everything from mass properties to date of launch.We describe in this paper a sensitivity analysis tool (Critical Factors Tool or CFT) developed to find the input variables or pairs of variables which by themselves significantly influence satisfaction of requirements or significantly affect key performance metrics (e.g., touchdown distance from target). Knowing these factors can inform robustness analysis, can inform where engineering resources are most needed, and could even affect operations. The contributions of this paper include the introduction of novel sensitivity measures, such as estimating success probability, and a technique for determining whether pairs of factors are interacting dependently or independently. The tool found that input variables such as moments, mass, thrust dispersions, and date of launch were found to be significant factors for success of various requirements. Examples are shown in this paper as well as a summary and physics discussion of EFT-1 driving factors that the tool found.

Effects of watershed land use and geomorphology on stream low flows during severe drought conditions in the southern Blue Ridge Mountains, Georgia and North Carolina

EPA Science Inventory

Watershed land use and topographic variability influence stream low flows, yet their interactions and relative influence remain unresolved. Our objective was to assess the relative influences of land use and watershed geomorphic characteristics on low flow variability in the sour...

An empirical comparison of key statistical attributes among potential ICU quality indicators.

PubMed

Brown, Sydney E S; Ratcliffe, Sarah J; Halpern, Scott D

2014-08-01

Good quality indicators should have face validity, relevance to patients, and be able to be measured reliably. Beyond these general requirements, good quality indicators should also have certain statistical properties, including sufficient variability to identify poor performers, relative insensitivity to severity adjustment, and the ability to capture what providers do rather than patients' characteristics. We assessed the performance of candidate indicators of ICU quality on these criteria. Indicators included ICU readmission, mortality, several length of stay outcomes, and the processes of venous-thromboembolism and stress ulcer prophylaxis provision. Retrospective cohort study. One hundred thirty-eight U.S. ICUs from 2001-2008 in the Project IMPACT database. Two hundred sixty-eight thousand eight hundred twenty-four patients discharged from U.S. ICUs. None. We assessed indicators' (1) variability across ICU-years; (2) degree of influence by patient vs. ICU and hospital characteristics using the Omega statistic; (3) sensitivity to severity adjustment by comparing the area under the receiver operating characteristic curve (AUC) between models including vs. excluding patient variables, and (4) correlation between risk adjusted quality indicators using a Spearman correlation. Large ranges of among-ICU variability were noted for all quality indicators, particularly for prolonged length of stay (4.7-71.3%) and the proportion of patients discharged home (30.6-82.0%), and ICU and hospital characteristics outweighed patient characteristics for stress ulcer prophylaxis (ω, 0.43; 95% CI, 0.34-0.54), venous thromboembolism prophylaxis (ω, 0.57; 95% CI, 0.53-0.61), and ICU readmissions (ω, 0.69; 95% CI, 0.52-0.90). Mortality measures were the most sensitive to severity adjustment (area under the receiver operating characteristic curve % difference, 29.6%); process measures were the least sensitive (area under the receiver operating characteristic curve % differences: venous thromboembolism prophylaxis, 3.4%; stress ulcer prophylaxis, 2.1%). None of the 10 indicators was clearly and consistently correlated with a majority of the other nine indicators. No indicator performed optimally across assessments. Future research should seek to define and operationalize quality in a way that is relevant to both patients and providers.

Fate and Contribution of Internal Wave-Forced Barnacle Settlers to Community Structure in Northern Baja California, a Year after Settlement

NASA Astrophysics Data System (ADS)

Lievana, A.; Ladah, L. B.; Lavin, M. F.; Filonov, A. E.; Tapia, F. J.; Leichter, J.; Valencia Gasti, J. A.

2016-02-01

Physical transport processes, such as nonlinear internal waves, operating within the coastal ocean of Baja California, Mexico, are diverse, variable and operate on a variety of temporal and spatial scales. Understanding the influence of nonlinear internal waves, in part responsible for the exchange of water properties between coastal and offshore environments, on the structure of intertidal communities is important for the generation of working ecological models. The relationship between the supply of ecological subsidies associated with physical transport processes that operate on relatively short spatial and temporal scales, such as the internal tide, and intertidal community structure must be understood as processes that operate on distinct spatial and temporal scales may be prone to react uniquely as the climate changes. We designed an experiment to quantify recruitment and adult survivorship of Chthamalus sp. whose settlement was associated with internal wave activity in the nearby ocean and found that the number of settlers was a robust predictor of the number of adults observed, indicating that post-settlement processes such as competition and predation are not likely to significantly affect the structure of the intertidal barnacle community resulting from internal-wave forced settlement.

Evidence of the dose effects of an antitobacco counteradvertising campaign.

PubMed

Sly, David F; Trapido, Ed; Ray, Sarah

2002-11-01

The objectives were to assess the cumulative effects of exposure to multiple antitobacco advertisements shown over a 22-month period on smoking uptake, and determine if there is evidence of a dose effect and how this effect operates through response to the campaign's major message theme and antitobacco attitudes. A follow-up telephone survey of persons ages 12-20 years was conducted after 22 months of the Florida "truth" antitobacco media campaign. Logistic regression analyses were used to estimate adjusted odds ratios for the likelihood that time-one nonsmokers would remain nonsmokers at time two by levels of confirmed advertisement awareness, self-reported influence of the campaign's message theme, and anti-tobacco industry manipulation attitudes. Separate cohorts are analyzed and controls include gender and time-one susceptibility. The likelihood of nonsmokers remaining nonsmokers increases as the number of ads confirmed, the self-reported influence of the campaign's major message theme, and the level of antitobacco attitudes increases. The pattern to these relationships holds within cohorts of young and older youth and for a cohort that has aged into the early young adult years. Considering all variables simultaneously suggests that ad confirmation operates through its effects on the influence of the message theme and antitobacco industry manipulation attitudes. There is evidence of a dose effect; however, considering only ad confirmation underestimates this. Antitobacco campaigns that target youth can have effects at least through the early young adult ages. The uniqueness of the Florida campaign may limit the generalization of reported results.

Reaction Times to Consecutive Automation Failures: A Function of Working Memory and Sustained Attention.

PubMed

Jipp, Meike

2016-12-01

This study explored whether working memory and sustained attention influence cognitive lock-up, which is a delay in the response to consecutive automation failures. Previous research has demonstrated that the information that automation provides about failures and the time pressure that is associated with a task influence cognitive lock-up. Previous research has also demonstrated considerable variability in cognitive lock-up between participants. This is why individual differences might influence cognitive lock-up. The present study tested whether working memory-including flexibility in executive functioning-and sustained attention might be crucial in this regard. Eighty-five participants were asked to monitor automated aircraft functions. The experimental manipulation consisted of whether or not an initial automation failure was followed by a consecutive failure. Reaction times to the failures were recorded. Participants' working-memory and sustained-attention abilities were assessed with standardized tests. As expected, participants' reactions to consecutive failures were slower than their reactions to initial failures. In addition, working-memory and sustained-attention abilities enhanced the speed with which participants reacted to failures, more so with regard to consecutive than to initial failures. The findings highlight that operators with better working memory and sustained attention have small advantages when initial failures occur, but their advantages increase across consecutive failures. The results stress the need to consider personnel selection strategies to mitigate cognitive lock-up in general and training procedures to enhance the performance of low ability operators. © 2016, Human Factors and Ergonomics Society.

Factors Influencing Team Behaviors in Surgery: A Qualitative Study to Inform Teamwork Interventions.

PubMed

Aveling, Emma-Louise; Stone, Juliana; Sundt, Thoralf; Wright, Cameron; Gino, Francesca; Singer, Sara

2018-07-01

Surgical excellence demands teamwork. Poor team behaviors negatively affect team performance and are associated with adverse events and worse outcomes. Interventions to improve surgical teamwork focusing on frontline team members' nontechnical skills have proliferated but shown mixed results. Literature on teamwork in organizations suggests that team behaviors are also contingent on psychosocial, cultural, and organizational factors. This study examined factors influencing surgical team behaviors to inform more contextually sensitive and effective approaches to optimizing surgical teamwork. This qualitative study of cardiac surgical teams in a large United States teaching hospital included 34 semistructured interviews. Thematic network analysis was used to examine perceptions of ideal teamwork and factors influencing team behaviors in the operating room. Perceptions of ideal teamwork were largely shared, but team members held discrepant views of which team and leadership behaviors enhanced or undermined teamwork. Other factors affecting team behaviors were related to the local organizational culture, including management of staff behavior, variable case demands, and team members' technical competence, and fitness of organizational structures and processes to support teamwork. These factors affected perceptions of what constituted optimal interpersonal and team behaviors in the operating room. Team behaviors are contextually contingent and organizationally determined, and beliefs about optimal behaviors are not necessarily shared. Interventions to optimize surgical teamwork require establishing consensus regarding best practice, ability to adapt as circumstances require, and organizational commitment to addressing contextual factors that affect teams. Copyright © 2018 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Influence of soil-water ratio on the performance of slurry phase bioreactor treating herbicide contaminated soil.

PubMed

Venkata Mohan, S; Ramakrishna, M; Shailaja, S; Sarma, P N

2007-09-01

The influence of soil-water ratio was studied on the performance of the slurry phase bioreactor operated in sequencing batch mode (anoxic-aerobic-anoxic microenvironments) during the bioremediation of soil contaminated with pendimethalin. The performance of the reactors was evaluated at different soil-water ratios (1:5-1:25; at soil loading rate (60 kg of soil/cum-day to 12 kg of soil/cum-day)) keeping the loading rate of pendimethalin constant (133.2 g/kg of soil-day) in six reactors and variable (66.6 g/kg of soil-day to 166.6 g/kg of soil-day) in other four reactors. At 1:20 soil-water ratio, the slurry phase system showed enhanced degradation of substrate (629 microg pendimethalin/g soil). The removal efficiency of pendimethalin in the reactors was dependent on the mass-transfer rates of the substrate from the soil to the aqueous phase. Soil-water ratio and substrate loading rates showed significant influence on the substrate portioning, substrate degradation efficiency and substrate desorption rate.

[Integration of demographic variables into development plans in the Sahel].

PubMed

Wane, H R

1992-07-01

A founding principle of the Program of Action of N'Djamena is the interdependence of population and development and the need for development strategies to take demographic factors into account. The concept of integration of population variables into development has evolved since its introduction in the 1974 World Population Plan of Action from a simple description of population size, growth rates, and distribution to a stress on harmonizing population policies and development policies with macroeconomic variables. The essence of the concept is the consideration given by development policies and programs to the interrelations between population, resources, the environment, and development factors. Population variables and goals should ideally be treated as endogenous variables in development planning, but in practice the extreme complexity of such a systematic approach limits its ability to be made operational. Usually the most crucial problems only are included. Integrated planning is composed of explicit or implicit population policies intended to influence demographic variables and of socioeconomic policies intended to adapt to demographic change. In the Sahel, only Senegal, Burkina Faso, and Mali have formal population policies, but around 1980 several countries of the region began to show interest in influencing demographic variables as they did economic variables. Fundamental principles for developing an integration strategy can be applied regardless or whether the plan is based on projections, analysis of interaction of a demographic variable with factors specific to a sector, or a monosectorial or multisectorial demoeconomic planning model. Demographic data is used more frequently in diagnosing problems than in developing projections or formulating objectives. The level of disaggregation of demographic projections and estimates tends to be low, despite the great potential utility of demographic projections in planning. Demographic projections can be useful in analyses of the extent of changes and the implications of alternative scenarios of development planning. The most frequently used demographic variables in development planning have been spatial distribution of the population and mortality. An examination of past development plans in Mali relating to population and nutrition and population and health reveals several inconsistencies between stated goals and strategies intended to achieve them. The incoherence can be explained in part by the absence of a coherent national population policy, the failure to translate the population policy into programs that take into account reciprocal effects of demographic trends and economic perspectives and their social effects, and the absence of disaggregated population projections. An example from Senegal demonstrates the constraints imposed by structural adjustment programs on the entire planning process.

Influence of summer water-level variability on St. Lawrence River-wetland fish assemblages

USGS Publications Warehouse

McKenna, J.E.; Barkley, J.L.; Johnson, J. H.

2008-01-01

Water-level and associated variability are substantial influences on wetland and shallow aquatic communities. The Akwesasne Wetland Complex is an extensive St. Lawrence River system affected by water regulation. The responses of fish assemblages to short-term summer water-level variation were examined throughout this section of the St. Lawrence River and its tributaries. An influence of water-level variability was detected on abundance of three common species [bluntnose minnow (Pimephales notatus), rock bass (Amboplites rupestris), and white sucker (Catastomus commersonii)] and explained 30-44% of variation. This influence has implications for water regulation and natural resource management, and a larger scope evaluation may reveal more extensive effects.

40 CFR 63.1207 - What are the performance testing requirements?

Code of Federal Regulations, 2010 CFR

2010-07-01

... operating conditions that are most likely to reflect daily maximum operating variability, similar to a... operating variability, similar to a dioxin/furan compliance test; (B) You have not changed the design or... document the temperature location measurement in the comprehensive performance test plan, as required by...

The Mauna Kea Weather Center: Custom Atmospheric Forecasting Support for Mauna Kea

NASA Astrophysics Data System (ADS)

Businger, Steven

2011-03-01

The success of operations at Mauna Kea Observatories is strongly influenced by weather conditions. The Mauna Kea Weather Center, an interdisciplinary research program, was established in 1999 to develop and provide custom weather support for Mauna Kea Observatories. The operational forecasting goals of the program are to facilitate the best possible use of favorable atmospheric conditions for scientific benefit and to ensure operational safety. During persistent clear periods, astronomical observing quality varies substantially due to changes in the vertical profiles of temperature, wind, moisture, and turbulence. Cloud and storm systems occasionally cause adverse or even hazardous conditions. A dedicated, daily, real-time mesoscale numerical modeling effort provides crucial forecast guidance in both cases. Several key atmospheric variables are forecast with sufficient skill to be of operational and scientific benefit to the telescopes on Mauna Kea. Summit temperature forecasts allow mirrors to be set to the ambient temperature to reduce image distortion. Precipitable water forecasts allow infrared observations to be prioritized according to atmospheric opacity. Forecasts of adverse and hazardous conditions protect the safety of personnel and allow for scheduling of maintenance when observing is impaired by cloud. The research component of the project continues to improve the accuracy and content of the forecasts. In particular, case studies have resulted in operational forecasts of astronomical observing quality, or seeing.

The Status and Future Directions for the GRACE Mission

NASA Astrophysics Data System (ADS)

Tapley, B. D.; Flechtner, F.; Watkins, M. M.; Bettadpur, S. V.

2015-12-01

The twin satellites of the Gravity Recovery and Climate Experiment (GRACE) were launched on March 17, 2002 and have operated for over 13 years. The mission objectives are to sense the spatial and temporal variations of the Earth's mass through its effects on the gravity field at the GRACE satellite altitude. The major cause of the time varying mass is water motion and the GRACE mission has provided a continuous decade long measurement sequences which characterizes the seasonal cycle of mass transport between the oceans, land, cryosphere and atmosphere; its inter-annual variability; and the climate driven secular, or long period, mass transport signals. In 2012, a complete reanalysis of the mission data, referred to as the RL05 data release, was initiated. The monthly solutions from this effort were released in mid-2013 with the mean fields following in 2014 and 2015. The mission is entering the final phases of operations. The current mission operations strategy emphasizes extending the mission lifetime to achieve mission overlap with the GRACE Follow On Mission. This presentation will review the mission status and the projections for mission lifetime, summarize plans for the RL 06 data re-analysis, describe the issues that influence the operations philosophy and discuss the impact the operations may have on the scientific data products.

The Current Status and Future Prospects for the GRACE Mission

NASA Astrophysics Data System (ADS)

Tapley, Byron; Flechtner, Frank; Watkins, Michael; Bettadpur, Srinivas; Boening, Carmen

2016-04-01

The twin satellites of the Gravity Recovery and Climate Experiment (GRACE) were launched on March 17, 2002 and have operated for over 13 years. The mission objectives are to sense the spatial and temporal variations of the Earth's mass through its effects on the gravity field at the GRACE satellite altitude. The major cause of the time varying mass is water motion and the GRACE mission has provided a continuous decade long measurement sequences which characterizes the seasonal cycle of mass transport between the oceans, land, cryosphere and atmosphere; its inter-annual variability; and the climate driven secular, or long period, mass transport signals. In 2012, the RLO5 solution, based on a complete reanalysis of the mission data, data release, was initiated. The monthly solutions from this effort were released in mid-2013 with the mean fields following in 2014 and 2015. The mission is entering the final phases of operations. The current mission operations strategy emphasizes extending the mission lifetime to achieve mission overlap with the GRACE Follow On Mission. This presentation will review the mission status and the projections for mission lifetime, summarize plans for the RL 06 data re-analysis, describe the issues that influence the operations philosophy and discuss the impact the operations may have on the scientific data products.

Analytical review based on statistics on good and poor financial performance of LPD in Bangli regency.

NASA Astrophysics Data System (ADS)

Yasa, I. B. A.; Parnata, I. K.; Susilawati, N. L. N. A. S.

2018-01-01

This study aims to apply analytical review model to analyze the influence of GCG, accounting conservatism, financial distress models and company size on good and poor financial performance of LPD in Bangli Regency. Ordinal regression analysis is used to perform analytical review, so that obtained the influence and relationship between variables to be considered further audit. Respondents in this study were LPDs in Bangli Regency, which amounted to 159 LPDs of that number 100 LPDs were determined as randomly selected samples. The test results found GCG and company size have a significant effect on both the good and poor financial performance, while the conservatism and financial distress model has no significant effect. The influence of the four variables on the overall financial performance of 58.8%, while the remaining 41.2% influenced by other variables. Size, FDM and accounting conservatism are variables, which are further recommended to be audited.

Patterns in the species-environment relationship depend on both scale and choice of response variables

Treesearch

Samuel A. Cushman; Kevin McGarigal

2004-01-01

Multi-scale investigations of species/environment relationships are an important tool in ecological research. The scale at which independent and dependent variables are measured, and how they are coded for analysis, can strongly influence the relationships that are discovered. However, little is known about how the coding of the dependent variable set influences...

Variability in urban soils influences the health and growth of native tree seedlings

Treesearch

Clara C. Pregitzer; Nancy F. Sonti; Richard A. Hallett

2016-01-01

Reforesting degraded urban landscapes is important due to the many benefits urban forests provide. Urban soils are highly variable, yet little is known about how this variability in urban soils influences tree seedling performance and survival. We conducted a greenhouse study to assess health, growth, and survival of four native tree species growing in native glacial...

Bubble formation dynamics in a planar co-flow configuration: Influence of geometric and operating characteristics

NASA Astrophysics Data System (ADS)

Gutiérrez-Montes, Cándido; Bolaños-Jiménez, Rocío; Martínez-Bazán, Carlos; Sevilla, Alejandro

2014-11-01

An experimental and numerical study has been performed to explore the influence of different geometric features and operating conditions on the dynamics of a water-air-water planar co-flow. Specifically, regarding the nozzle used, the inner-to-outer thickness ratio of the air injector, β = Hi/Ho, the water-to-air thickness ratio, h = Hw/Ho, and the shape of the injector tip, have been described. As for the operating conditions, the water exit velocity profile under constant flow rate and constant air feeding pressure has been assessed. The results show that the jetting-bubbling transition is promoted for increasing values of β, decreasing values of h, rounded injector tip, and for uniform water exit velocity profiles. As for the bubble formation frequency, it increases with increasing values of β, decreasing values of h, rounded injector and parabolic-shaped water exit profiles. Furthermore, the bubble formation frequency has been shown to be lower under constant air feeding pressure conditions than at constant gas flow rate conditions. Finally, the effectiveness of a time-variable air feeding stream has been numerically studied, determining the forcing receptivity space in the amplitude-frequency plane. Experimental results corroborate the effectiveness of this control technique. Work supported by Spanish MINECO, Junta de Andalucía, European Funds and UJA under Projects DPI2011-28356-C03-02, DPI2011-28356-C03-03, P11-TEP7495 and UJA2013/08/05.

Influence of meteorological variables on rainfall partitioning for deciduous and coniferous tree species in urban area

NASA Astrophysics Data System (ADS)

Zabret, Katarina; Rakovec, Jože; Šraj, Mojca

2018-03-01

Rainfall partitioning is an important part of the ecohydrological cycle, influenced by numerous variables. Rainfall partitioning for pine (Pinus nigra Arnold) and birch (Betula pendula Roth.) trees was measured from January 2014 to June 2017 in an urban area of Ljubljana, Slovenia. 180 events from more than three years of observations were analyzed, focusing on 13 meteorological variables, including the number of raindrops, their diameter, and velocity. Regression tree and boosted regression tree analyses were performed to evaluate the influence of the variables on rainfall interception loss, throughfall, and stemflow in different phenoseasons. The amount of rainfall was recognized as the most influential variable, followed by rainfall intensity and the number of raindrops. Higher rainfall amount, intensity, and the number of drops decreased percentage of rainfall interception loss. Rainfall amount and intensity were the most influential on interception loss by birch and pine trees during the leafed and leafless periods, respectively. Lower wind speed was found to increase throughfall, whereas wind direction had no significant influence. Consideration of drop size spectrum properties proved to be important, since the number of drops, drop diameter, and median volume diameter were often recognized as important influential variables.

Sensitivity analysis of a short distance atmospheric dispersion model applied to the Fukushima disaster

NASA Astrophysics Data System (ADS)

Périllat, Raphaël; Girard, Sylvain; Korsakissok, Irène; Mallet, Vinien

2015-04-01

In a previous study, the sensitivity of a long distance model was analyzed on the Fukushima Daiichi disaster case with the Morris screening method. It showed that a few variables, such as horizontal diffusion coefficient or clouds thickness, have a weak influence on most of the chosen outputs. The purpose of the present study is to apply a similar methodology on the IRSN's operational short distance atmospheric dispersion model, called pX. Atmospheric dispersion models are very useful in case of accidental releases of pollutant to minimize the population exposure during the accident and to obtain an accurate assessment of short and long term environmental and sanitary impact. Long range models are mostly used for consequences assessment while short range models are more adapted to the early phases of the crisis and are used to make prognosis. The Morris screening method was used to estimate the sensitivity of a set of outputs and to rank the inputs by their influences. The input ranking is highly dependent on the considered output, but a few variables seem to have a weak influence on most of them. This first step revealed that interactions and non-linearity are much more pronounced with the short range model than with the long range one. Afterward, the Sobol screening method was used to obtain more quantitative results on the same set of outputs. Using this method was possible for the short range model because it is far less computationally demanding than the long range model. The study also confronts two parameterizations, Doury's and Pasquill's models, to contrast their behavior. The Doury's model seems to excessively inflate the influence of some inputs compared to the Pasquill's model, such as the altitude of emission and the air stability which do not have the same role in the two models. The outputs of the long range model were dominated by only a few inputs. On the contrary, in this study the influence is shared more evenly between the inputs.

Impact of Collection Equipment on Ash Variability of Baled Corn Stover Biomass for Bioenergy

DOE Office of Scientific and Technical Information (OSTI.GOV)

William Smith; Jeffery Einerson; Kevin Kenney

2014-09-01

Cost-effective conversion of agricultural residues for renewable energy hinges not only on the material’s quality but also the biorefinery’s ability to reliably measure quality specifications. The ash content of biomass is one such specification, influencing pretreatment and disposal costs for the conversion facility and the overall value of a delivered lot of biomass. The biomass harvest process represents a primary pathway for accumulation of soil-derived ash within baled material. In this work, the influence of five collection techniques on the total ash content and variability of ash content within baled corn stover in southwest Kansas is discussed. The equipment testedmore » included a mower for cutting the corn stover stubble, a basket rake, wheel rake, or shred flail to gather the stover, and a mixed or uniform in-feed baler for final collection. The results showed mean ash content to range from 11.5 to 28.2 % depending on operational choice. Resulting impacts on feedstock costs for a biochemical conversion process range from $5.38 to $22.30 Mg-1 based on the loss of convertible dry matter and ash disposal costs. Collection techniques that minimized soil contact (shred flail or nonmowed stubble) were shown to prevent excessive ash contamination, whereas more aggressive techniques (mowing and use of a wheel rake) caused greater soil disturbance and entrainment within the final baled material. Material sampling and testing were shown to become more difficult as within-bale ash variability increased, creating uncertainty around feedstock quality and the associated costs of ash mitigation.« less

Alteration of natural (37)Ar activity concentration in the subsurface by gas transport and water infiltration.

PubMed

Guillon, Sophie; Sun, Yunwei; Purtschert, Roland; Raghoo, Lauren; Pili, Eric; Carrigan, Charles R

2016-05-01

High (37)Ar activity concentration in soil gas is proposed as a key evidence for the detection of underground nuclear explosion by the Comprehensive Nuclear Test-Ban Treaty. However, such a detection is challenged by the natural background of (37)Ar in the subsurface, mainly due to Ca activation by cosmic rays. A better understanding and improved capability to predict (37)Ar activity concentration in the subsurface and its spatial and temporal variability is thus required. A numerical model integrating (37)Ar production and transport in the subsurface is developed, including variable soil water content and water infiltration at the surface. A parameterized equation for (37)Ar production in the first 15 m below the surface is studied, taking into account the major production reactions and the moderation effect of soil water content. Using sensitivity analysis and uncertainty quantification, a realistic and comprehensive probability distribution of natural (37)Ar activity concentrations in soil gas is proposed, including the effects of water infiltration. Site location and soil composition are identified as the parameters allowing for a most effective reduction of the possible range of (37)Ar activity concentrations. The influence of soil water content on (37)Ar production is shown to be negligible to first order, while (37)Ar activity concentration in soil gas and its temporal variability appear to be strongly influenced by transient water infiltration events. These results will be used as a basis for practical CTBTO concepts of operation during an OSI. Copyright © 2016 Elsevier Ltd. All rights reserved.

Space Transportation System Availability Requirement and Its Influencing Attributes Relationships

NASA Technical Reports Server (NTRS)

Rhodes, Russell E.; Adams, Timothy C.; McCleskey, Carey M.

2008-01-01

It is important that engineering and management accept the need for an availability requirement that is derived with its influencing attributes. It is the intent of this paper to provide the visibility of relationships of these major attribute drivers (variables) to each other and the resultant system inherent availability. Also important to provide bounds of the variables providing engineering the insight required to control the system's engineering solution, e.g., these influencing attributes become design requirements also. These variables will drive the need to provide integration of similar discipline functions or technology selection to allow control of the total parts count. The relationship of selecting a reliability requirement will place a constraint on parts count to achieve a given availability requirement or if allowed to increase the parts count will drive the system reliability requirement higher. They also provide the understanding for the relationship of mean repair time (or mean down time) to maintainability, e.g., accessibility for repair, and both the mean time between failure, e.g., reliability of hardware and availability. The concerns and importance of achieving a strong availability requirement is driven by the need for affordability, the choice of using the two launch solution for the single space application, or the need to control the spare parts count needed to support the long stay in either orbit or on the surface of the moon. Understanding the requirements before starting the architectural design concept will avoid considerable time and money required to iterate the design to meet the redesign and assessment process required to achieve the results required of the customer's space transportation system. In fact the impact to the schedule to being able to deliver the system that meets the customer's needs, goals, and objectives may cause the customer to compromise his desired operational goal and objectives resulting in considerable increased life cycle cost of the fielded space transportation system.

Space Transportation System Availability Requirements and Its Influencing Attributes Relationships

NASA Technical Reports Server (NTRS)

Rhodes, Russell E.; Adams, Timothy C.; McCleskey, Carey M.

2008-01-01

It is important that engineering and management accept the need for an availability requirement that is derived with its influencing attributes. It is the intent of this paper to provide the visibility of relationships of these major attribute drivers (variables) to each other and the resultant system inherent availability. Also important to provide bounds of the variables providing engineering the insight required to control the system's engineering solution, e.g., these influencing attributes become design requirements also. These variables will drive the need to provide integration of similar discipline functions or technology selection to allow control of the total parts count. The relationship of selecting a reliability requirement will place a constraint on parts count to achieve a given availability requirement or if allowed to increase the parts count will drive the system reliability requirement higher. They also provide the understanding for the relationship of mean repair time (or mean down time) to maintainability, e.g., accessibility for repair, and both the mean time between failure, e.g., reliability of hardware and availability. The concerns and importance of achieving a strong availability requirement is driven by the need for affordability, the choice of using the two launch solution for the single space application, or the need to control the spare parts count needed to support the long stay in either orbit or on the surface of the moon. Understanding the requirements before starting the architectural design concept will avoid considerable time and money required to iterate the design to meet the redesign and assessment process required to achieve the results required of the customer's space transportation system. In fact the impact to the schedule to being able to deliver the system that meets the customer's needs, goals, and objectives may cause the customer to compromise his desired operational goal and objectives resulting in considerable increased life cycle cost of the fielded space transportation system.

Gait performance is not influenced by working memory when walking at a self-selected pace.

PubMed

Grubaugh, Jordan; Rhea, Christopher K

2014-02-01

Gait performance exhibits patterns within the stride-to-stride variability that can be indexed using detrended fluctuation analysis (DFA). Previous work employing DFA has shown that gait patterns can be influenced by constraints, such as natural aging or disease, and they are informative regarding a person's functional ability. Many activities of daily living require concurrent performance in the cognitive and gait domains; specifically working memory is commonly engaged while walking, which is considered dual-tasking. It is unknown if taxing working memory while walking influences gait performance as assessed by DFA. This study used a dual-tasking paradigm to determine if performance decrements are observed in gait or working memory when performed concurrently. Healthy young participants (N = 16) performed a working memory task (automated operation span task) and a gait task (walking at a self-selected speed on a treadmill) in single- and dual-task conditions. A second dual-task condition (reading while walking) was included to control for visual attention, but also introduced a task that taxed working memory over the long term. All trials involving gait lasted at least 10 min. Performance in the working memory task was indexed using five dependent variables (absolute score, partial score, speed error, accuracy error, and math error), while gait performance was indexed by quantifying the mean, standard deviation, and DFA α of the stride interval time series. Two multivariate analyses of variance (one for gait and one for working memory) were used to examine performance in the single- and dual-task conditions. No differences were observed in any of the gait or working memory dependent variables as a function of task condition. The results suggest the locomotor system is adaptive enough to complete a working memory task without compromising gait performance when walking at a self-selected pace.

Factors Influencing Postoperative Complications in Reconstructive Microsurgery for Head and Neck Cancer.

PubMed

Lo, Shih-Lun; Yen, Yu-Hsiu; Lee, Pi-Jung; Liu, Chih-Ho Charles; Pu, Chi-Ming

2017-04-01

The present study aimed to analyze multiple variables and to determine the factors influencing postoperative complications in reconstructive microsurgeries for head and neck cancer. This was a retrospective review of the medical records of patients with head and neck cancer who underwent free flap reconstruction after ablation surgery at the Cathay General Hospital (Taipei, Taiwan) from January 2010 to December 2014. Clinical and surgical procedure-related factors were retrieved from a database and analyzed. Major complications included flap failure and life-threatening events. Minor complications were defined as requiring only routine wound care or conservative treatments. To evaluate group differences, the χ 2 test was applied for categorical variables and the Mann-Whitney U test was used for continuous variables. In total, 158 patients (145 men [91.8%], 13 women [8.2%]) were included in this study. The mean age of the study population was 52.4 years (range, 34 to 84 yr). The mean body mass index (BMI) was 23.71 kg/m 2 . Most patients (93.7%) had a history of cigarette smoking. Some patients had diabetes (20.3%) and hypertension (31.6%). The percentage of patients who underwent radiotherapy before surgery was 19.6%. The percentage whose flap required a salvage operation was 8.9%. The success rate of the microvascular surgeries was 95.6%. The major complication rate was 6.3% and the minor complication rate was 27.8%. No surgical mortality was noted. In these patients, poor nutrition status, indicated by low BMI and low albumin level, was associated with a greater tendency to develop postoperative complications. Patients who had diabetes or who had received radiotherapy before surgery had a high risk for major complications. A large skin paddle seemed to be an influencing factor for minor complications, such as wound dehiscence and superficial loss of flaps. Copyright © 2016 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Increasing Influence of Societal Response Variables in Coastal Evolution Projections (Invited)

NASA Astrophysics Data System (ADS)

Gayes, P. T.; McCoy, C. A.; Pietrafesa, L. J.

2010-12-01

Recent efforts to project changes in coastal erosion and vulnerability of the state of South Carolina’s (SC’s) oceanfront for different scenarios of future sea level have reinforced the significance of the influence of societal modifications and response to past and anticipated coastal change in these systems. For large reaches of the SC coast human interactions have been a dominant signal driving coastal change across annual to decadal scales. Over the last 20 years, SC’s shoreline has been advanced seawards in many areas due to a combination of sustained societal commitment to beach nourishment and to a lull in atmospheric storms; reversing the long-term erosional trend of shoreline change. Adjacent areas not yet threatened or where coastal defense is unsupported economically have continued to migrate landwards. Locally, efforts focused on stabilizing the subaerial beach have not moderated long-term shoreward migration of the shoreface changing the overall morphology of the coastal boundary waves and currents are operating against. These societal effects, coupled with realistic, substative assessments of future atmospheric storm activity and sea level variability, both over scales of seasons to multi-decades, require consideration to realistically project future coastal behavior across time and spatial scales for planning and resource management. As with future climate and sea level variability effects on the shoreline, the scale and intensity of societal response is not static or precisely projected spatially and temporally into the future. With continued expansion of coastal development and erosion into previously lightly developed and defended coastal areas, societal influences should be expected to increase. Increasing cost of larger scale defenses will likely drive pressure for hardened structures to enhance ”softer” nourishment strategies. However, this strategy would further modify the ability of nature to respond to natural forces. Nourishment programs are strongly cyclic and can act in or out of phase with natural cyclic (inlet migration, sea level variability) or stochastic (storms) drivers with significant effects on coastal response and predictions of coastal behavior. Economic cycles and events may similarly moderate timing and scale of coastal defense relative to natural drivers. Societal decisions to not, enhance and or even abandon and remove existing engineering structures as future forces and costs increase, can result in a disproportional response and potentially failure of a section of coast. Some communities have expressed confidence in the ability to maintain the oceanfront shoreline against most projections of sea level rise over the next 100 years. The long-term trend in sea level change may be less important than naturally occurring regional scale, seasonal to inter-annual to multi-decadal variability in sea level; and these are complex but deterministic. There is less confidence, however, in the ability to combat passive submergence and associated flooding issues behind the immediate oceanfront. To the extent that may influence commitment to defend the oceanfront could strongly influence coastal behavior and stability in the long term.

On switching response surface models, with applications to the structural health monitoring of bridges

NASA Astrophysics Data System (ADS)

Worden, K.; Cross, E. J.

2018-01-01

Structural Health Monitoring (SHM) is the engineering discipline of diagnosing damage and estimating safe remaining life for structures and systems. Often, SHM is accomplished by detecting changes in measured quantities from the structure of interest; if there are no competing explanations for the changes, one infers that they are the result of damage. If the structure of interest is subject to changes in its environmental or operational conditions, one must understand the effects of these changes in order that one does not falsely claim that damage has occurred when changes in measured quantities are observed. This problem - the problem of confounding influences - is particularly pressing for civil infrastructure where the given structure is usually openly exposed to the weather and may be subject to strongly varying operational conditions. One approach to understanding confounding influences is to construct a data-based response surface model that can represent measurement variations as a function of environmental and operational variables. The models can then be used to remove environmental and operational variations so that change detection algorithms signal the occurrence of damage alone. The current paper is concerned with such response surface models in the case of SHM of bridges. In particular, classes of response surface models that can switch discontinuously between regimes are discussed. Recently, it has been shown that Gaussian Process (GP) models are an effective means of developing response surface or surrogate models. However, the GP approach runs into difficulties if changes in the latent variables cause the structure of interest to abruptly switch between regimes. A good example here, which is well known in the SHM literature, is given by the Z24 Bridge in Switzerland which completely changed its dynamical behaviour when it cooled below zero degrees Celsius as the asphalt of the deck stiffened. The solution proposed here is to adopt the recently-proposed Treed Gaussian Process (TGP) model as an alternative. The approach is illustrated here on the Z24 bridge and also on data from the Tamar Bridge in the UK which shows marked switching behaviour in certain of its dynamical characteristics when its ambient wind conditions change. It is shown that treed GPs provide an effective approach to response surface modelling and that in the Tamar case, a linear model is in fact sufficient to solve the problem.

The Algae Testbed Public-Private Partnership (ATP 3 ) framework; establishment of a national network of testbed sites to support sustainable algae production

DOE PAGES

McGowen, John; Knoshaug, Eric P.; Laurens, Lieve M. L.; ...

2017-07-01

Well-controlled experiments that directly compare seasonal algal productivities across geographically distinct locations have not been reported before. To fill this gap, six cultivation testbed facilities were chosen across the United States to evaluate different climatic zones with respect to algal biomass productivity potential. The geographical locations and climates were as follows: Southwest, desert; Western, coastal; Southeast, inland; Southeast, coastal; Pacific, tropical; and Midwest, greenhouse. The testbed facilities were equipped with identical systems for inoculum production and open pond operation and methods were standardized across all testbeds to ensure accurate measurement of physical and biological variables. The ability of the testbedmore » sites to culture and analyze the same algal species, Nannochloropsis oceanica KA32, using identical pond operational and data collection procedures was evaluated during the same seasonal timeframe. This manuscript describes the results of a first-of-its-kind coordinated testbed validation field study while providing critical details on how geographical variations in temperature, light, and weather variables influenced algal productivity, nitrate consumption, and biomass composition. We found distinct differences in growth characteristics due to the geographic location and the resulting climatic and seasonal conditions across the sites, with the highest productivities observed at the desert Southwest and tropical Pacific regions, followed by the Western coastal region. The lowest productivities were observed at the Southeast inland and Midwest greenhouse locations. These differences in productivities among the sites correlated with the differences in pond water temperature and available solar radiation. In addition two sites, the tropical Pacific and Southeast inland experienced unusual events, spontaneous flocculation, and unusually cold and wet (rainfall) conditions respectively, that negatively affected outdoor algal growth. In addition, minor variability in productivity was observed between the different experimental treatments at each site, much smaller compared to differences due to geographic location. Finally, the successful demonstration of the coordinated and standardized operation of the testbed sites established a rigorous basis for future validation of algal strains and operational conditions and protocols across a geographically diverse testbed network.« less

The Algae Testbed Public-Private Partnership (ATP 3 ) framework; establishment of a national network of testbed sites to support sustainable algae production

DOE Office of Scientific and Technical Information (OSTI.GOV)

McGowen, John; Knoshaug, Eric P.; Laurens, Lieve M. L.

Well-controlled experiments that directly compare seasonal algal productivities across geographically distinct locations have not been reported before. To fill this gap, six cultivation testbed facilities were chosen across the United States to evaluate different climatic zones with respect to algal biomass productivity potential. The geographical locations and climates were as follows: Southwest, desert; Western, coastal; Southeast, inland; Southeast, coastal; Pacific, tropical; and Midwest, greenhouse. The testbed facilities were equipped with identical systems for inoculum production and open pond operation and methods were standardized across all testbeds to ensure accurate measurement of physical and biological variables. The ability of the testbedmore » sites to culture and analyze the same algal species, Nannochloropsis oceanica KA32, using identical pond operational and data collection procedures was evaluated during the same seasonal timeframe. This manuscript describes the results of a first-of-its-kind coordinated testbed validation field study while providing critical details on how geographical variations in temperature, light, and weather variables influenced algal productivity, nitrate consumption, and biomass composition. We found distinct differences in growth characteristics due to the geographic location and the resulting climatic and seasonal conditions across the sites, with the highest productivities observed at the desert Southwest and tropical Pacific regions, followed by the Western coastal region. The lowest productivities were observed at the Southeast inland and Midwest greenhouse locations. These differences in productivities among the sites correlated with the differences in pond water temperature and available solar radiation. In addition two sites, the tropical Pacific and Southeast inland experienced unusual events, spontaneous flocculation, and unusually cold and wet (rainfall) conditions respectively, that negatively affected outdoor algal growth. In addition, minor variability in productivity was observed between the different experimental treatments at each site, much smaller compared to differences due to geographic location. Finally, the successful demonstration of the coordinated and standardized operation of the testbed sites established a rigorous basis for future validation of algal strains and operational conditions and protocols across a geographically diverse testbed network.« less

Power partial-discard strategy to obtain improved performance for simulated moving bed chromatography.

PubMed

Chung, Ji-Woo; Kim, Kyung-Min; Yoon, Tae-Ung; Kim, Seung-Ik; Jung, Tae-Sung; Han, Sang-Sup; Bae, Youn-Sang

2017-12-22

A novel power partial-discard (PPD) strategy was developed as a variant of the partial-discard (PD) operation to further improve the separation performance of the simulated moving bed (SMB) process. The PPD operation varied the flow rates of discard streams by introducing a new variable, the discard amount (DA) as well as varying the reported variable, discard length (DL), while the conventional PD used fixed discard flow rates. The PPD operations showed significantly improved purities in spite of losses in recoveries. Remarkably, the PPD operation could provide more enhanced purity for a given recovery or more enhanced recovery for a given purity than the PD operation. The two variables, DA and DL, in the PPD operation played a key role in achieving the desired purity and recovery. The PPD operations will be useful for attaining high-purity products with reasonable recoveries. Copyright © 2017 Elsevier B.V. All rights reserved.

Operational Impacts of Operating Reserve Demand Curves on Production Cost and Reliability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krad, Ibrahim; Ibanez, Eduardo; Ela, Erik

The electric power industry landscape is continually evolving. As emerging technologies such as wind, solar, electric vehicles, and energy storage systems become more cost-effective and present in the system, traditional power system operating strategies will need to be reevaluated. The presence of wind and solar generation (commonly referred to as variable generation) may result in an increase in the variability and uncertainty of the net load profile. One mechanism to mitigate this is to schedule and dispatch additional operating reserves. These operating reserves aim to ensure that there is enough capacity online in the system to account for the increasedmore » variability and uncertainty occurring at finer temporal resolutions. A new operating reserve strategy, referred to as flexibility reserve, has been introduced in some regions. A similar implementation is explored in this paper, and its implications on power system operations are analyzed.« less

Operational Impacts of Operating Reserve Demand Curves on Production Cost and Reliability: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krad, Ibrahim; Ibanez, Eduardo; Ela, Erik

The electric power industry landscape is continually evolving. As emerging technologies such as wind, solar, electric vehicles, and energy storage systems become more cost-effective and present in the system, traditional power system operating strategies will need to be reevaluated. The presence of wind and solar generation (commonly referred to as variable generation) may result in an increase in the variability and uncertainty of the net load profile. One mechanism to mitigate this is to schedule and dispatch additional operating reserves. These operating reserves aim to ensure that there is enough capacity online in the system to account for the increasedmore » variability and uncertainty occurring at finer temporal resolutions. A new operating reserve strategy, referred to as flexibility reserve, has been introduced in some regions. A similar implementation is explored in this paper, and its implications on power system operations are analyzed.« less

Sludge accumulation pattern inside oxidation ditch case study.

PubMed

Fouad, Moharram; El-Morsy, Ahmed

2014-01-01

The sludge accumulation pattern of an oxidation ditch (OD) plant treating municipal wastewater was observed under dry and wet weather conditions, during 3 years of operation. The accumulation patterns along the ditches and their rates were revealed. In addition, the composition of the accumulation was investigated. Finally, the ratio of sand and volatile particles, mixed liquor suspended solids (MLSS), and mixed liquor volatile suspended solids, as well as the removal efficiency were also observed against the accumulated sludge. Further, a laboratory-scale channel was used to investigate the settleability of grit after mixing with variable values of MLSS. The observed results indicated that the economical design and operation of ODs using a velocity value between 0.3-0.35 m/s is not recommended, to avoid the settling of all solids. High values of MLSS and sludge age need high horizontal velocity (more than 0.35 m/s) and more power to avoid settling problems and system failure. The influence of flow velocity on the sludge settleability was studied, enabling better planning of future ditch design and operation.

Use of laterite for the removal of fluoride from contaminated drinking water.

PubMed

Sarkar, Mitali; Banerjee, Aparna; Pramanick, Partha Pratim; Sarkar, Asit R

2006-10-15

The effects of different operational variables on the mechanistic function of laterite in removal of fluoride have been investigated. Thermodynamic parameters such as free energy change, enthalpy, and entropy of the process, as well as the sorption isotherm, were evaluated. The extent of solute removal is determined by initial solute concentration, operational conditions, laterite dose, and solution pH. For a fixed set of experimental conditions, a model equation is developed from which the percent removal corresponding to each load of fluoride is determined. The mechanism of fluoride adsorption is governed by the zero point charge of laterite and follows a first-order rate equation. pH has a vital role influencing the surface characteristics of laterite. To simulate the flow dynamics, fluoride solution was run through a fixed bed column. The pattern of breakthrough curves for different influent fluoride concentration, pH, and column bed height was characterized. The column efficiency was tested from the bed depth-service time model. The elution of the retained fluoride was studied and the effectiveness of column operation was determined by the retention-elution cycles.

[Age and time estimation during different types of activity].

PubMed

Gareev, E M; Osipova, L G

1980-01-01

The study was concerned with the age characteristics of verbal and operative estimation of time intervals filled with different types of mental and physical activity as well as those free of it. The experiment was conducted on 85 subjects, 7--24 years of age. In all age groups and in both forms of time estimation (except verbal estimation in 10--12 years old children) there was a significant connection between the interval estimation and the type of activity. In adults and in 7--8 years old children, the connection was significantly tighter in operative estimations than in verbal ones. Unlike senior school children and adults, in 7--12 years old children there were sharp differences in precision between operative and verbal estimations and a discordance of their changes under the influence of activity. Precision and variability were rather similar in all age groups. It is suggested that the obtained data show heterochronity and a different rate of development of the higher nervous activity mechanisms providing for reflection of time in the form of verbal and voluntary motor reactions to the given interval.

An effective hybrid immune algorithm for solving the distributed permutation flow-shop scheduling problem

NASA Astrophysics Data System (ADS)

Xu, Ye; Wang, Ling; Wang, Shengyao; Liu, Min

2014-09-01

In this article, an effective hybrid immune algorithm (HIA) is presented to solve the distributed permutation flow-shop scheduling problem (DPFSP). First, a decoding method is proposed to transfer a job permutation sequence to a feasible schedule considering both factory dispatching and job sequencing. Secondly, a local search with four search operators is presented based on the characteristics of the problem. Thirdly, a special crossover operator is designed for the DPFSP, and mutation and vaccination operators are also applied within the framework of the HIA to perform an immune search. The influence of parameter setting on the HIA is investigated based on the Taguchi method of design of experiment. Extensive numerical testing results based on 420 small-sized instances and 720 large-sized instances are provided. The effectiveness of the HIA is demonstrated by comparison with some existing heuristic algorithms and the variable neighbourhood descent methods. New best known solutions are obtained by the HIA for 17 out of 420 small-sized instances and 585 out of 720 large-sized instances.

Ground-level climate at a peatland wind farm in Scotland is affected by wind turbine operation

NASA Astrophysics Data System (ADS)

Armstrong, Alona; Burton, Ralph R.; Lee, Susan E.; Mobbs, Stephen; Ostle, Nicholas; Smith, Victoria; Waldron, Susan; Whitaker, Jeanette

2016-04-01

The global drive to produce low-carbon energy has resulted in an unprecedented deployment of onshore wind turbines, representing a significant land use change for wind energy generation with uncertain consequences for local climatic conditions and the regulation of ecosystem processes. Here, we present high-resolution data from a wind farm collected during operational and idle periods that shows the wind farm affected several measures of ground-level climate. Specifically, we discovered that operational wind turbines raised air temperature by 0.18 °C and absolute humidity (AH) by 0.03 g m-3 during the night, and increased the variability in air, surface and soil temperature throughout the diurnal cycle. Further, the microclimatic influence of turbines on air temperature and AH decreased logarithmically with distance from the nearest turbine. These effects on ground-level microclimate, including soil temperature, have uncertain implications for biogeochemical processes and ecosystem carbon cycling, including soil carbon stocks. Consequently, understanding needs to be improved to determine the overall carbon balance of wind energy.

Surface Salinity Variability in the North Atlantic During Recent Decades

NASA Technical Reports Server (NTRS)

Haekkinen, Sirpa

2001-01-01

The sea surface salinity (SSS) variability in the North Atlantic is investigated using numerical model simulations for the last 50 years based on atmospheric forcing variability from Comprehensive Atmosphere Ocean Data Set (COADS) and National Center for Environmental Prediction / National Center for Atmospheric Research (NCEP/NCAR) Reanalysis. The largest interannual and longer term variability occurs in two regions: the Labrador Sea and the North Equatorial Countercurrent (NECC) region. In both regions the seasonality of the surface salinity variability is prominent with the maximum standard deviation occurring in the summer/fall period. In the Labrador Sea the summer SSS anomalies far exceed those of wintertime in amplitude. The interannual SSS variability in the subpolar gyre can be attributed to two factors: excess ice melt and heat flux (i.e. deep mixing) variations. On the other hand, heat flux variability can also lead to meridional overturning changes on decadal time scales such that weak overturning is manifested in fresh surface conditions in the subpolar gyre. The overturning changes also influence the NECC region SSS variability. Moreover, the subpolar freshening events are expected to occur during the negative phase of North Atlantic Oscillation which is associated with a weak wintertime surface heat loss in the subpolar gyre. No excess sea ice melt or precipitation is necessary for the formation of the fresh anomalies, because with the lack of wide-spread deep mixing, the fresh water that would be expected based on climatology, would accumulate at the surface. Thus, the fresh water 'conveyor' in the Atlantic operates via the overturning circulation such that deep mixing inserts fresh water while removing heat from the water column.

A biometeorological procedure for weather forecast to assess the optimal outdoor clothing insulation.

PubMed

Morabito, Marco; Crisci, Alfonso; Cecchi, Lorenzo; Modesti, Pietro Amedeo; Maracchi, Giampiero; Gensini, Gian Franco; Orlandini, Simone

2008-09-01

Clothing insulation represents an important parameter strongly dependent on climate/weather variability and directly involved in the assessment of the human energy balance. Few studies tried to explore the influence of climate changes on the optimal clothing insulation for outdoor spaces. For this reason, the aim of this work was to investigate mainly the optimal outdoor minimum clothing insulation value required to reach the thermal neutrality (min_clo) related to climate change on a seasonal basis. Subsequently, we developed an example of operational biometeorological procedure to provide 72-hour forecast maps concerning the min_clo. Hourly meteorological data were provided by three Italian weather stations located in Turin, Rome and Palermo, for the period 1951-1995. Environmental variables and subjective characteristics referred to an average adult young male at rest and at a very high metabolic rate were used as input variables to calculate the min_clo by using a thermal index based on the human energy balance. Trends of min_clo were assessed by a non-parametric statistical method. Results showed a lower magnitude of trends in a subject at a very high metabolic rate than at rest. Turin always showed a decrease of min_clo during the study period and prevalently negative trends were also observed in Palermo. On the other hand, an opposite situation was observed in Rome, especially during the morning in all seasons. The development of a daily operational procedure to forecast customized min_clo could provide useful information for the outdoor clothing fitting that might help to reduce the weather-related human health risk.

Infusion phlebitis in post-operative patients: when and why.

PubMed

Monreal, M; Oller, B; Rodriguez, N; Vega, J; Torres, T; Valero, P; Mach, G; Ruiz, A E; Roca, J

1999-01-01

The most common complication of intravenous therapy is infusion phlebitis. This study was done to prospectively assess its frequency in a series of consecutive patients who will undergo surgery, and to identify which variables may predict an increased risk for phlebitis. 400 consecutive patients who will undergo surgery in a general surgery department were included. Only the first catheter, inserted the day before surgery, was taken into account. Eighteen variables (from the infusion, the catheter and from the patient) were prospectively evaluated for their contribution to the occurrence of phlebitis. 60/400 patients (15%) developed phlebitis, and most of them needed insertion of a further catheter. The univariate analysis showed that patients who developed phlebitis were older, and their pre-operative levels of both blood haemoglobin and neutrophil cound were significantly higher than those in patients who did not develop phlebitis. However, the multivariate analysis only confirmed the association with blood haemoglobin levels: the risk of phlebitis sharply increased in the patients with the highest haemoglobin levels. As to the influence of time on phlebitis development, there was a significant decrease in the day-specific risk, from the 5th day on. In our series, blood haemoglobin levels were found to be the only variable associated to a higher risk of phlebitis. Besides, in contrast with the recommendations by the Centers for Disease Control, no significant increase in the day-specific risk of phlebitis was found. Thus, a guideline to select the type of catheter to be inserted in an individual patient is suggested. Copyright 2000 S. Karger AG, Basel

An Examination of Variables Which Influence High School Students to Enroll in an Undergraduate Engineering or Physical Science Major

ERIC Educational Resources Information Center

Porter, Christopher H.

2011-01-01

The purpose of this study was to examine the variables which influence a high school student to enroll in an engineering discipline versus a physical science discipline. Data was collected utilizing the High School Activities, Characteristics, and Influences Survey, which was administered to students who were freshmen in an engineering or physical…

Effects of Watershed Land Use and Geomorphology on Stream Low Flows During Severe Drought Conditions in the Southern Blue Ridge Mountains, Georgia and North Carolina, United States

EPA Science Inventory

Land use and physiographic variability influence stream low flows, yet their interactions and relative influence remain unresolved. Our objective was to assess the influence of land use and watershed geomorphic characteristics on low-flow variability in the southern Blue Ridge Mo...

Low cloud properties influenced by cosmic rays

PubMed

Marsh; Svensmark

2000-12-04

The influence of solar variability on climate is currently uncertain. Recent observations have indicated a possible mechanism via the influence of solar modulated cosmic rays on global cloud cover. Surprisingly the influence of solar variability is strongest in low clouds (

Development of a Patient-Based Model for Estimating Operative Times for Robot-Assisted Radical Prostatectomy.

PubMed

Huben, Neil; Hussein, Ahmed; May, Paul; Whittum, Michelle; Kraswowki, Collin; Ahmed, Youssef; Jing, Zhe; Khan, Hijab; Kim, Hyung; Schwaab, Thomas; Underwood Iii, Willie; Kauffman, Eric; Mohler, James L; Guru, Khurshid A

2018-04-10

To develop a methodology for predicting operative times for robot-assisted radical prostatectomy (RARP) using preoperative patient, disease, procedural and surgeon variables to facilitate operating room (OR) scheduling. The model included preoperative metrics: BMI, ASA score, clinical stage, National Comprehensive Cancer Network (NCCN) risk, prostate weight, nerve-sparing status, extent and laterality of lymph node dissection, and operating surgeon (6 surgeons were included in the study). A binary decision tree was fit using a conditional inference tree method to predict operative times. The variables most associated with operative time were determined using permutation tests. The data was split at the value of the variable that results in the largest difference in means for surgical time across the split. This process was repeated recursively on the resultant data. 1709 RARPs were included. The variable most strongly associated with operative time was the surgeon (surgeons 2 and 4 - 102 minutes shorter than surgeons 1, 3, 5, and 6, p<0.001). Among surgeons 2 and 4, BMI had the strongest association with surgical time (p<0.001). Among patients operated by surgeons 1, 3, 5 and 6, RARP time was again most strongly associated with the surgeon performing RARP. Surgeons 1, 3, and 6 were on average 76 minutes faster than surgeon 5 (p<0.001). The regression tree output in the form of box plots showed operative time median and ranges according to patient, disease, procedural and surgeon metrics. We developed a methodology that can predict operative times for RARP based on patient, disease and surgeon variables. This methodology can be utilized for quality control, facilitate OR scheduling and maximize OR efficiency.

Multiple and variable speed electrical generator systems for large wind turbines

NASA Technical Reports Server (NTRS)

Andersen, T. S.; Hughes, P. S.; Kirschbaum, H. S.; Mutone, G. A.

1982-01-01

A cost effective method to achieve increased wind turbine generator energy conversion and other operational benefits through variable speed operation is presented. Earlier studies of multiple and variable speed generators in wind turbines were extended for evaluation in the context of a specific large sized conceptual design. System design and simulation have defined the costs and performance benefits which can be expected from both two speed and variable speed configurations.

Method for assessing motor insulation on operating motors

DOEpatents

Kueck, John D.; Otaduy, Pedro J.

1997-01-01

A method for monitoring the condition of electrical-motor-driven devices. The method is achieved by monitoring electrical variables associated with the functioning of an operating motor, applying these electrical variables to a three phase equivalent circuit and determining non-symmetrical faults in the operating motor based upon symmetrical components analysis techniques.

Ethanol Seeking by Long Evans Rats Is Not Always a Goal-Directed Behavior

PubMed Central

Mangieri, Regina A.; Cofresí, Roberto U.; Gonzales, Rueben A.

2012-01-01

Background Two parallel and interacting processes are said to underlie animal behavior, whereby learning and performance of a behavior is at first via conscious and deliberate (goal-directed) processes, but after initial acquisition, the behavior can become automatic and stimulus-elicited (habitual). With respect to instrumental behaviors, animal learning studies suggest that the duration of training and the action-outcome contingency are two factors involved in the emergence of habitual seeking of “natural” reinforcers (e.g., sweet solutions, food or sucrose pellets). To rigorously test whether behaviors reinforced by abused substances such as ethanol, in particular, similarly become habitual was the primary aim of this study. Methodology/Principal Findings Male Long Evans rats underwent extended or limited operant lever press training with 10% sucrose/10% ethanol (10S10E) reinforcement (variable interval (VI) or (VR) ratio schedule of reinforcement), or with 10% sucrose (10S) reinforcement (VI schedule only). Once training and pretesting were complete, the impact of outcome devaluation on operant behavior was evaluated after lithium chloride injections were paired with the reinforcer, or unpaired 24 hours later. After limited, but not extended instrumental training, lever pressing by groups trained under VR with 10S10E and under VI with 10S was sensitive to outcome devaluation. In contrast, responding by both the extended and limited training 10S10E VI groups was not sensitive to ethanol devaluation during the test for habitual behavior. Conclusions/Significance Operant behavior by rats trained to self-administer an ethanol-sucrose solution showed variable sensitivity to a change in the value of ethanol, with relative insensitivity developing sooner in animals that received time-variable ethanol reinforcement during training sessions. One important implication, with respect to substance abuse in humans, is that initial learning about the relationship between instrumental actions and the opportunity to consume ethanol-containing drinks can influence the time course for the development or expression of habitual ethanol seeking behavior. PMID:22870342

Improving fire season definition by optimized temporal modelling of daily human-caused ignitions.

PubMed

Costafreda-Aumedes, S; Vega-Garcia, C; Comas, C

2018-07-01

Wildfire suppression management is usually based on fast control of all ignitions, especially in highly populated countries with pervasive values-at-risk. To minimize values-at-risk loss by improving response time of suppression resources it is necessary to anticipate ignitions, which are mainly caused by people. Previous studies have found that human-ignition patterns change spatially and temporally depending on socio-economic activities, hence, the deployment of suppression resources along the year should consider these patterns. However, full suppression capacity is operational only within legally established fire seasons, driven by past events and budgets, which limits response capacity and increases damages out of them. The aim of this study was to assess the temporal definition of fire seasons from the perspective of human-ignition patterns for the case study of Spain, where people cause over 95% of fires. Humans engage in activities that use fire as a tool in certain periods within a year, and in locations linked to specific spatial factors. Geographic variables (population, infrastructures, physiography and land uses) were used as explanatory variables for human-ignition patterns. The changing influence of these geographic variables on occurrence along the year was analysed with day-by-day logistic regression models. Daily models were built for all the municipal units in the two climatic regions in Spain (Atlantic and Mediterranean Spain) from 2002 to 2014, and similar models were grouped within continuous periods, designated as ignition-based seasons. We found three ignition-based seasons in the Mediterranean region and five in the Atlantic zones, not coincidental with calendar seasons, but with a high degree of agreement with current legally designated operational fire seasons. Our results suggest that an additional late-winter-early-spring fire season in the Mediterranean area and the extension of this same season in the Atlantic zone should be re-considered for operational purposes in the future. Copyright © 2018 Elsevier Ltd. All rights reserved.

Influences of system uncertainties on the numerical transfer path analysis of engine systems

NASA Astrophysics Data System (ADS)

Acri, A.; Nijman, E.; Acri, A.; Offner, G.

2017-10-01

Practical mechanical systems operate with some degree of uncertainty. In numerical models uncertainties can result from poorly known or variable parameters, from geometrical approximation, from discretization or numerical errors, from uncertain inputs or from rapidly changing forcing that can be best described in a stochastic framework. Recently, random matrix theory was introduced to take parameter uncertainties into account in numerical modeling problems. In particular in this paper, Wishart random matrix theory is applied on a multi-body dynamic system to generate random variations of the properties of system components. Multi-body dynamics is a powerful numerical tool largely implemented during the design of new engines. In this paper the influence of model parameter variability on the results obtained from the multi-body simulation of engine dynamics is investigated. The aim is to define a methodology to properly assess and rank system sources when dealing with uncertainties. Particular attention is paid to the influence of these uncertainties on the analysis and the assessment of the different engine vibration sources. Examples of the effects of different levels of uncertainties are illustrated by means of examples using a representative numerical powertrain model. A numerical transfer path analysis, based on system dynamic substructuring, is used to derive and assess the internal engine vibration sources. The results obtained from this analysis are used to derive correlations between parameter uncertainties and statistical distribution of results. The derived statistical information can be used to advance the knowledge of the multi-body analysis and the assessment of system sources when uncertainties in model parameters are considered.

Analysis of the Coupled Influence of Hydraulic Conductivity and Porosity Heterogeneity on Probabilistic Risk Analysis

NASA Astrophysics Data System (ADS)

Libera, A.; Henri, C.; de Barros, F.

2017-12-01

Heterogeneities in natural porous formations, mainly manifested through the hydraulic conductivity (K) and, to a lesser degree, the porosity (Φ), largely control subsurface flow and solute transport. The influence of the heterogeneous structure of K on flow and solute transport processes has been widely studied, whereas less attention is dedicated to the joint heterogeneity of conductivity and porosity fields. Our study employs computational tools to investigate the joint effect of the spatial variabilities of K and Φ on the transport behavior of a solute plume. We explore multiple scenarios, characterized by different levels of heterogeneity of the geological system, and compare the computational results from the joint K and Φ heterogeneous system with the results originating from the generally adopted constant porosity case. In our work, we assume that the heterogeneous porosity is positively correlated to hydraulic conductivity. We perform numerical Monte Carlo simulations of conservative and reactive contaminant transport in a 3D aquifer. Contaminant mass and plume arrival times at multiple control planes and/or pumping wells operating under different extraction rates are analyzed. We employ different probabilistic metrics to quantify the risk at the monitoring locations, e.g., increased lifetime cancer risk and exceedance of Maximum Contaminant Levels (MCLs), under multiple transport scenarios (i.e., different levels of heterogeneity, conservative or reactive solutes and different contaminant species). Results show that early and late arrival times of the solute mass at the selected sensitive locations (i.e. control planes/pumping wells) as well as risk metrics are strongly influenced by the spatial variability of the Φ field.

Predictors of outcome after elective endovascular abdominal aortic aneurysm repair and external validation of a risk prediction model.

PubMed

Wisniowski, Brendan; Barnes, Mary; Jenkins, Jason; Boyne, Nicholas; Kruger, Allan; Walker, Philip J

2011-09-01

Endovascular abdominal aortic aneurysm (AAA) repair (EVAR) has been associated with lower operative mortality and morbidity than open surgery but comparable long-term mortality and higher delayed complication and reintervention rates. Attention has therefore been directed to identifying preoperative and operative variables that influence outcomes after EVAR. Risk-prediction models, such as the EVAR Risk Assessment (ERA) model, have also been developed to help surgeons plan EVAR procedures. The aims of this study were (1) to describe outcomes of elective EVAR at the Royal Brisbane and Women's Hospital (RBWH), (2) to identify preoperative and operative variables predictive of outcomes after EVAR, and (3) to externally validate the ERA model. All elective EVAR procedures at the RBWH before July 1, 2009, were reviewed. Descriptive analyses were performed to determine the outcomes. Univariate and multivariate analyses were performed to identify preoperative and operative variables predictive of outcomes after EVAR. Binomial logistic regression analyses were used to externally validate the ERA model. Before July 1, 2009, 197 patients (172 men), who were a mean age of 72.8 years, underwent elective EVAR at the RBWH. Operative mortality was 1.0%. Survival was 81.1% at 3 years and 63.2% at 5 years. Multivariate analysis showed predictors of survival were age (P = .0126), American Society of Anesthesiologists (ASA) score (P = .0180), and chronic obstructive pulmonary disease (P = .0348) at 3 years and age (P = .0103), ASA score (P = .0006), renal failure (P = .0048), and serum creatinine (P = .0022) at 5 years. Aortic branch vessel score was predictive of initial (30-day) type II endoleak (P = .0015). AAA tortuosity was predictive of midterm type I endoleak (P = .0251). Female sex was associated with lower rates of initial clinical success (P = .0406). The ERA model fitted RBWH data well for early death (C statistic = .906), 3-year survival (C statistic = .735), 5-year survival (C statistic = .800), and initial type I endoleak (C statistic = .850). The outcomes of elective EVAR at the RBWH are broadly consistent with those of a nationwide Australian audit and recent randomized trials. Age and ASA score are independent predictors of midterm survival after elective EVAR. The ERA model predicts mortality-related outcomes and initial type I endoleak well for RBWH elective EVAR patients. Copyright © 2011 Society for Vascular Surgery. All rights reserved.

Influence of kinematic parameters on pole vault results in top juniors.

PubMed

Gudelj, Ines; Zagorac, Nebojsa; Babić, Vesna

2013-05-01

The aim of this research was to analyse the kinematic parameters and to ascertain the influence of those parameters on the pole vault result. The entity sample of the research consisted of successful vaults of 30 athletes, whose attempts were recorded at the European Junior Athletics Championships. The examinees performed the vaults as part of the qualification competition for the finale and the finale of the competition itself The examinees were 17-19 years old, and the range of their top results was from 4.90 to 5.30 m. The results of the regression analysis showed a significant influence of the predictor variables on the effective pole vault height. The centre of body mass height was mostly influenced by the following variables: TS - takeoff velocity, LSS - last step velocity, PSS - penultimate step velocity, TAPR - trunk angle at the moment of the pole release. The following variables had lesser, but still a significant influence: CBMDM - centre of body mass distance at the pole release moment, and MCMVV - time of pole straightening. Generally, the information gained by this research indicates the significant influence of the kinematic parameters on the pole vault result. Therefore, the conclusion is that the result efficacy in the pole vault is primarily determined by the variables defined by the motor capabilities, but also by the indicators determining the vault activity realization technique. The variables that define the body position during the pole release (trunk angle and centre of mass distance) have heomost significant influence on the vault performance technique, while the motor capabilities influence the last two run up steps velocity, take off speed and the time of pole straightening.

Long-term climate patterns in Alaskan surface temperature and precipitation and their biological consequences

USGS Publications Warehouse

Simpson, James J.; Hufford, Gary L.; Fleming, Michael D.; Berg, Jared S.; Ashton, J.B.

2002-01-01

Mean monthly climate maps of Alaskan surface temperature and precipitation produced by the parameter-elevation regression on independent slopes model (PRISM) were analyzed. Alaska is divided into interior and coastal zones with consistent but different climatic variability separated by a transition region; it has maximum interannual variability but low long-term mean variability. Pacific decadal oscillation (PDO)- and El Nino Southern Oscillation (ENSO)-type events influence Alaska surface temperatures weakly (1-2/spl deg/C) statewide. PDO has a stronger influence than ENSO on precipitation but its influence is largely localized to coastal central Alaska. The strongest influence of Arctic oscillation (AO) occurs in northern and interior Alaskan precipitation. Four major ecosystems are defined. A major eco-transition zone occurs between the interior boreal forest and the coastal rainforest. Variability in insolation, surface temperature, precipitation, continentality, and seasonal changes in storm track direction explain the mapped ecosystems. Lack of westward expansion of the interior boreal forest into the western shrub tundra is influenced by the coastal marine boundary layer (enhanced cloud cover, reduced insolation, cooler surface and soil temperatures).

Engine-Operating Load Influences Diesel Exhaust Composition and Cardiopulmonary and Immune Responses

PubMed Central

Campen, Matthew J.; Harrod, Kevin S.; Seagrave, JeanClare; Seilkop, Steven K.; Mauderly, Joe L.

2011-01-01

Background: The composition of diesel engine exhaust (DEE) varies by engine type and condition, fuel, engine operation, and exhaust after treatment such as particle traps. DEE has been shown to increase inflammation, susceptibility to infection, and cardiovascular responses in experimentally exposed rodents and humans. Engines used in these studies have been operated at idle, at different steady-state loads, or on variable-load cycles, but exposures are often reported only as the mass concentration of particulate matter (PM), and the effects of different engine loads and the resulting differences in DEE composition are unknown. Objectives: We assessed the impacts of load-related differences in DEE composition on models of inflammation, susceptibility to infection, and cardiovascular toxicity. Methods: We assessed inflammation and susceptibility to viral infection in C57BL/6 mice and cardiovascular toxicity in APOE–/– mice after being exposed to DEE generated from a single-cylinder diesel generator operated at partial or full load. Results: At the same PM mass concentration, partial load resulted in higher proportions of particle organic carbon content and a smaller particle size than did high load. Vapor-phase hydrocarbon content was greater at partial load. Compared with high-load DEE, partial-load DEE caused greater responses in heart rate and T-wave morphology, in terms of both magnitude and rapidity of onset of effects, consistent with previous findings that systemic effects may be driven largely by the gas phase of the exposure atmospheres. However, high-load DEE caused more lung inflammation and greater susceptibility to viral infection than did partial load. Conclusions: Differences in engine load, as well as other operating variables, are important determinants of the type and magnitude of responses to inhaled DEE. PM mass concentration alone is not a sufficient basis for comparing or combining results from studies using DEE generated under different conditions. PMID:21524982

Associations between pre-operative radiographic changes and outcomes after total knee joint replacement for osteoarthritis.

PubMed

Dowsey, M M; Nikpour, M; Dieppe, P; Choong, P F M

2012-10-01

To assess the influence of pre-operative X-ray changes on the response to total knee joint replacement (TKR). We included patients from one centre who underwent primary TKR (n = 478) for osteoarthritis in 2006 and 2007. The International Knee Society score (IKSS) and short form health survey were collected pre-operatively and at 1 and 2 years after surgery. Pre-operative radiographs were read to assess Kellgren and Lawrence (K-L) grading, individual radiographic features using the OARSI atlas, and subchondral bone attrition using the Ahlbach method. The main independent variable was a modified (K-L) grade. The outcome variables were the IKSS pain and function scores. Covariates included demographic features, co-morbidities, baseline pain and function, prosthesis type, and the use of patella resurfacing. Multivariable linear regression models were created to assess the relationships between pre-operative X-ray findings and pain and function outcomes. On average, pain and function improved greatly following surgery. However, pain relief was unsatisfactory in about 30%, and functional improvement suboptimal in about 50%. OR (95% CI) for ongoing moderate-severe pain at 12 months for modified K-L grades; <3: 5.39 (1.23-15.69), 3a: 2.62 (1.21-5.67), 3b: 1.81 (1.00-3.26), 4a: 2.06 (1.05-4.05) when compared to 4b. OR (95% CI) for poor function at 12 months were; 3a: 2.81 (1.23-6.39) and 4a: 2.45 (1.22-4.91), when compared to 4b. Patients with more severe radiographic knee damage at the time of surgery are most likely to have substantial gains in terms of both pain relief and improved function as a result of a TKR. Copyright © 2012 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

Survival Prediction in Patients Undergoing Open-Heart Mitral Valve Operation After Previous Failed MitraClip Procedures.

PubMed

Geidel, Stephan; Wohlmuth, Peter; Schmoeckel, Michael

2016-03-01

The objective of this study was to analyze the results of open heart mitral valve operations for survival prediction in patients with previously unsuccessful MitraClip procedures. Thirty-three consecutive patients who underwent mitral valve surgery in our institution were studied. At a median of 41 days, they had previously undergone one to five futile MitraClip implantations. At the time of their operations, patients were 72.6 ± 10.3 years old, and the calculated risk, using the European System for Cardiac Operative Risk Evaluation (EuroSCORE) II, was a median of 26.5%. Individual outcomes were recorded, and all patients were monitored postoperatively. Thirty-day mortality was 9.1%, and the overall survival at 2.2 years was 60.6%. Seven cardiac-related and six noncardiac deaths occurred. Univariate survival regression models demonstrated a significant influence of the following variables on survival: EuroSCORE II (p = 0.0022), preoperative left ventricular end-diastolic dimension (p = 0.0052), left ventricular ejection fraction (p = 0.0249), coronary artery disease (p = 0.0385), and severe pulmonary hypertension (p = 0.0431). Survivors showed considerable improvements in their New York Heart Association class (p < 0.0001), left ventricular ejection fraction (p = 0.0080), grade of mitral regurgitation (p = 0.0350), and mitral valve area (p = 0.0486). Survival after mitral repair was not superior to survival after replacement. Indications for surgery after failed MitraClip procedures must be considered with the greatest of care. Variables predicting postoperative survival should be taken into account regarding the difficult decision as to whether to operate or not. Our data suggest that replacement of the pretreated mitral valve is probably the more reasonable concept rather than complex repairs. When the EuroSCORE II at the time of surgery exceeds 30%, conservative therapy is advisable. Copyright © 2016 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

The effects and interactions of student, teacher, and setting variables on reading outcomes for kindergartners receiving supplemental reading intervention.

PubMed

Hagan-Burke, Shanna; Coyne, Michael D; Kwok, Oi-Man; Simmons, Deborah C; Kim, Minjung; Simmons, Leslie E; Skidmore, Susan T; Hernandez, Caitlin L; McSparran Ruby, Maureen

2013-01-01

This exploratory study examined the influences of student, teacher, and setting characteristics on kindergarteners' early reading outcomes and investigated whether those relations were moderated by type of intervention. Participants included 206 kindergarteners identified as at risk for reading difficulties and randomly assigned to one of two supplemental interventions: (a) an experimental explicit, systematic, code-based program or (b) their schools' typical kindergarten reading intervention. Results from separate multilevel structural equation models indicated that among student variables, entry-level alphabet knowledge was positively associated with phonemic and decoding outcomes in both conditions. Entry-level rapid automatized naming also positively influenced decoding outcomes in both conditions. However, its effect on phonemic outcomes was statistically significant only among children in the typical practice comparison condition. Regarding teacher variables, the quality of instruction was associated with significantly higher decoding outcomes in the typical reading intervention condition but had no statistically significant influence on phonemic outcomes in either condition. Among setting variables, instruction in smaller group sizes was associated with better phonemic outcomes in the comparison condition but had no statistically significant influence on outcomes of children in the intervention group. Mode of delivery (i.e., pullout vs. in class) had no statistically significant influence on either outcome variable.

Analysis of potential factors affecting microbiological cultures in tissue donors during procurement.

PubMed

Lannau, B; Van Geyt, C; Van Maele, G; Beele, H

2015-03-01

During the procurement of musculoskeletal grafts contamination may occur. As this might be detrimental for the acceptor, it is important to know which variables influence this occurrence and to alter procurement protocols accordingly. From 2004 to 2012 we gathered information on 6,428 allografts obtained from 291 donors. Using a multiple regression model we attempted to determine the factors that influence the contamination risk during procurement. We used the following variables: cause of death, type of hospital (i.e. university hospital vs. general hospital), previous blood vessel donation, previous organ donation, donor age, time between death and the start of the procurement, duration of the procurement, number of people attending the procurement and the number of procured grafts. The multiple regression model was only able to explain 5 % of the variability of the used outcome variable. None of the variables examined appear to have an important influence on the contamination risk.

36 CFR 3.10 - What are the regulations regarding operating a vessel while under the influence of alcohol and/or...

Code of Federal Regulations, 2010 CFR

2010-07-01

... regarding operating a vessel while under the influence of alcohol and/or drugs? 3.10 Section 3.10 Parks... ACTIVITIES § 3.10 What are the regulations regarding operating a vessel while under the influence of alcohol...) Under the influence of alcohol, a drug or drugs, or any combination thereof, to a degree that renders...

Information Operations and Public Affairs: A Union of Influence

DTIC Science & Technology

2012-03-22

Information Operations,” (Quantico VA: United States Marine Corps, May 15, 1998) http://www.dtic.mil/dtic/tr/fulltext/u2/a400016.pdf (accessed December 11...Information Operations and Public Affairs: A Union of Influence by Lieutenant Colonel Duane A. Opperman United States Marine ...inform and influence audiences, gaps may exist. Both public affairs and information operations have defined mission sets and are necessarily separated

Spike Pattern Structure Influences Synaptic Efficacy Variability under STDP and Synaptic Homeostasis. I: Spike Generating Models on Converging Motifs

PubMed Central

Bi, Zedong; Zhou, Changsong

2016-01-01

In neural systems, synaptic plasticity is usually driven by spike trains. Due to the inherent noises of neurons and synapses as well as the randomness of connection details, spike trains typically exhibit variability such as spatial randomness and temporal stochasticity, resulting in variability of synaptic changes under plasticity, which we call efficacy variability. How the variability of spike trains influences the efficacy variability of synapses remains unclear. In this paper, we try to understand this influence under pair-wise additive spike-timing dependent plasticity (STDP) when the mean strength of plastic synapses into a neuron is bounded (synaptic homeostasis). Specifically, we systematically study, analytically and numerically, how four aspects of statistical features, i.e., synchronous firing, burstiness/regularity, heterogeneity of rates and heterogeneity of cross-correlations, as well as their interactions influence the efficacy variability in converging motifs (simple networks in which one neuron receives from many other neurons). Neurons (including the post-synaptic neuron) in a converging motif generate spikes according to statistical models with tunable parameters. In this way, we can explicitly control the statistics of the spike patterns, and investigate their influence onto the efficacy variability, without worrying about the feedback from synaptic changes onto the dynamics of the post-synaptic neuron. We separate efficacy variability into two parts: the drift part (DriftV) induced by the heterogeneity of change rates of different synapses, and the diffusion part (DiffV) induced by weight diffusion caused by stochasticity of spike trains. Our main findings are: (1) synchronous firing and burstiness tend to increase DiffV, (2) heterogeneity of rates induces DriftV when potentiation and depression in STDP are not balanced, and (3) heterogeneity of cross-correlations induces DriftV together with heterogeneity of rates. We anticipate our work important for understanding functional processes of neuronal networks (such as memory) and neural development. PMID:26941634

The Influence of the Student Mobility Rate on the Graduation Rate in the State of New Jersey

ERIC Educational Resources Information Center

Ross, Lavetta S.

2016-01-01

This study examined the influence of the student mobility rate on the high school graduation rate of schools in the state of New Jersey. Variables found to have an influence on the graduation rate in the extant literature were evaluated and reported. The analysis included multiple and hierarchical regression models for school variables (i.e.,…

Prediction of Short-Distance Aerial Movement of Phakopsora pachyrhizi Urediniospores Using Machine Learning.

PubMed

Wen, L; Bowen, C R; Hartman, G L

2017-10-01

Dispersal of urediniospores by wind is the primary means of spread for Phakopsora pachyrhizi, the cause of soybean rust. Our research focused on the short-distance movement of urediniospores from within the soybean canopy and up to 61 m from field-grown rust-infected soybean plants. Environmental variables were used to develop and compare models including the least absolute shrinkage and selection operator regression, zero-inflated Poisson/regular Poisson regression, random forest, and neural network to describe deposition of urediniospores collected in passive and active traps. All four models identified distance of trap from source, humidity, temperature, wind direction, and wind speed as the five most important variables influencing short-distance movement of urediniospores. The random forest model provided the best predictions, explaining 76.1 and 86.8% of the total variation in the passive- and active-trap datasets, respectively. The prediction accuracy based on the correlation coefficient (r) between predicted values and the true values were 0.83 (P < 0.0001) and 0.94 (P < 0.0001) for the passive and active trap datasets, respectively. Overall, multiple machine learning techniques identified the most important variables to make the most accurate predictions of movement of P. pachyrhizi urediniospores short-distance.

Analysis of the El Niño/La Niña-Southern Oscillation variability and malaria in the Estado Sucre, Venezuela.

PubMed

Delgado-Petrocelli, Laura; Córdova, Karenia; Camardiel, Alberto; Aguilar, Víctor H; Hernández, Denise; Ramos, Santiago

2012-09-01

The last decade has seen an unprecedented, worldwide acceleration of environmental and climate changes. These processes impact the dynamics of natural systems, which include components associated with human communities such as vector-borne diseases. The dynamics of environmental and climate variables, altered by global change as reported by the Intergovernmental Panel on Climate Change, affect the distribution of many tropical diseases. Complex systems, e.g. the El Niño/La Niña-Southern Oscillation (ENSO), in which environmental variables operate synergistically, can provoke the reemergence and emergence of vector-borne diseases at new sites. This research investigated the influence of ENSO events on malaria incidence by determining the relationship between climate variations, expressed as warm, cold and neutral phases, and their relation to the number of malaria cases in some north-eastern municipalities of Venezuela (Estado Sucre) during the period 1990-2000. Significant differences in malaria incidence were found, particularly in the La Niña ENSO phases (cold) of moderate intensity. These findings should be taken into account for surveillance and control in the future as they shed light on important indicators that can lead to reduced vulnerability to malaria.

Monitoring household waste recycling centres performance using mean bin weight analyses.

PubMed

Maynard, Sarah; Cherrett, Tom; Waterson, Ben

2009-02-01

This paper describes a modelling approach used to investigate the significance of key factors (vehicle type, compaction type, site design, temporal effects) in influencing the variability in observed nett amenity bin weights produced by household waste recycling centres (HWRCs). This new method can help to quickly identify sites that are producing significantly lighter bins, enabling detailed back-end analyses to be efficiently targeted and best practice in HWRC operation identified. Tested on weigh ticket data from nine HWRCs across West Sussex, UK, the model suggests that compaction technique, vehicle type, month and site design explained 76% of the variability in the observed nett amenity weights. For each factor, a weighting coefficient was calculated to generate a predicted nett weight for each bin transaction and three sites were subsequently identified as having similar characteristics but returned significantly different mean nett bin weights. Waste and site audits were then conducted at the three sites to try and determine the possible sources of the remaining variability. Significant differences were identified in the proportions of contained waste (bagged), wood, and dry recyclables entering the amenity waste stream, particularly at one site where significantly less contaminated waste and dry recyclables were observed.

Guidelines for the operation of variable message signs on state highways

DOT National Transportation Integrated Search

2004-06-01

A variable message sign (VMS) is a traffic control device whose message can be changed manually, electrically, mechanically, or electromechanically to provide motorists with information about traffic congestion, traffic crashes, maintenance operation...

Martian Surface Boundary Layer Characterization: Enabling Environmental Data for Science, Engineering and Human Exploration

NASA Technical Reports Server (NTRS)

England, C.

2000-01-01

For human or large robotic exploration of Mars, engineering devices such as power sources will be utilized that interact closely with the Martian environment. Heat sources for power production, for example, will use the low ambient temperature for efficient heat rejection. The Martian ambient, however, is highly variable, and will have a first order influence on the efficiency and operation of all large-scale equipment. Diurnal changes in temperature, for example, can vary the theoretical efficiency of power production by 15% and affect the choice of equipment, working fluids, and operating parameters. As part of the Mars Exploration program, missions must acquire the environmental data needed for design, operation and maintenance of engineering equipment including the transportation devices. The information should focus on the variability of the environment, and on the differences among locations including latitudes, altitudes, and seasons. This paper outlines some of the WHY's, WHAT's and WHERE's of the needed data, as well as some examples of how this data will be used. Environmental data for engineering design should be considered a priority in Mars Exploration planning. The Mars Thermal Environment Radiator Characterization (MTERC), and Dust Accumulation and Removal Technology (DART) experiments planned for early Mars landers are examples of information needed for even small robotic missions. Large missions will require proportionately more accurate data that encompass larger samples of the Martian surface conditions. In achieving this goal, the Mars Exploration program will also acquire primary data needed for understanding Martian weather, surface evolution, and ground-atmosphere interrelationships.

Advanced investigation on the change in the streamflow into the water source of the middle route of China's water diversion project

NASA Astrophysics Data System (ADS)

She, Dunxian; Xia, Jun; Shao, Quanxi; Taylor, John A.; Zhang, Liping; Zhang, Xiang; Zhang, Yanjun; Gu, Huanghe

2017-07-01

To alleviate water shortage in northern China, the middle route of the South to North Water Diversion Project (MRP) was constructed by the Chinese government. A dramatic reduction in the annual streamflow into Danjiangkou Reservoir (ASDR), the water source of MRP, during 1990 has raised some concerns on the MRP's operation. This paper employed an advanced segmented regression model with more recent data to have a clear picture and understand the changing pattern of the ASDR. Our study first revealed a zigzag changing pattern (decreasing-increasing-decreasing-increasing) of ASDR during 1960-2013, which was supported by statistical criteria compared with a monotonic or single abrupt change. Particularly, the significantly decreasing trend from 1990s was reversed after 2000, and such change may relieve the concern about the water availability in the future. Sensitivity analysis showed that changes in streamflow were largely influenced by the combined effects of precipitation (P) and potential evapotranspiration (ET0) and were more sensitive to P than ET0. As ET0 is estimated from other primary variables, further analysis was conducted to understand the sensitivities of ET0 to its primary driving variables (wind speed, actual vapor pressure, temperature, and sunshine duration) and indicated that ET0 is mostly sensitive to actual vapor pressure during 1960-2013. The findings will assist the MRP's operation and management. Moreover, the results in this study also indicate that an adaptive water diversion plan, rather than the current plan with a constant annual amount of diversion water, might be a better option in the MRP's operation.

The experimental studies of operating modes of a diesel-generator set at variable speed

NASA Astrophysics Data System (ADS)

Obukhov, S. G.; Plotnikov, I. A.; Surkov, M. A.; Sumarokova, L. P.

2017-02-01

A diesel generator set working at variable speed to save fuel is studied. The results of experimental studies of the operating modes of an autonomous diesel generator set are presented. Areas for regulating operating modes are determined. It is demonstrated that the transfer of the diesel generator set to variable speed of the diesel engine makes it possible to improve the energy efficiency of the autonomous generator source, as well as the environmental and ergonomic performance of the equipment as compared with general industrial analogues.

Optimal Operation of Variable Speed Pumping System in China's Eastern Route Project of S-to-N Water Diversion Project

NASA Astrophysics Data System (ADS)

Cheng, Jilin; Zhang, Lihua; Zhang, Rentian; Gong, Yi; Zhu, Honggeng; Deng, Dongsheng; Feng, Xuesong; Qiu, Jinxian

2010-06-01

A dynamic planning model for optimizing operation of variable speed pumping system, aiming at minimum power consumption, was proposed to achieve economic operation. The No. 4 Jiangdu Pumping Station, a source pumping station in China's Eastern Route of South-to-North Water Diversion Project, is taken as a study case. Since the sump water level of Jiangdu Pumping Station is affected by the tide of Yangtze River, the daily-average heads of the pumping system varies yearly from 3.8m to 7.8m and the tide level difference in one day up to 1.2m. Comparisons of operation electricity cost between optimized variable speed and fixed speed operations of pumping system were made. When the full load operation mode is adopted, whether or not electricity prices in peak-valley periods are considered, the benefits of variable speed operation cannot compensate the energy consumption of the VFD. And when the pumping system operates in part load and the peak-valley electricity prices are considered, the pumping system should cease operation or lower its rotational speed in peak load hours since the electricity price are much higher, and to the contrary the pumping system should raise its rotational speed in valley load hours to pump more water. The computed results show that if the pumping system operates in 80% or 60% loads, the energy consumption cost of specified volume of water will save 14.01% and 26.69% averagely by means of optimal variable speed operation, and the investment on VFD will be paid back in 2 or 3 years. However, if the pumping system operates in 80% or 60% loads and the energy cost is calculated in non peak-valley electricity price, the repayment will be lengthened up to 18 years. In China's S-to-N Water Diversion Project, when the market operation and peak-valley electricity prices are taken into effect to supply water and regulate water levels in regulation reservoirs as Hongzehu Lake, Luomahu Lake, etc. the economic operation of water-diversion pumping stations will be vital, and the adoption of VFDs to achieve optimal operation may be a good choice.

Influence of the optimization methods on neural state estimation quality of the drive system with elasticity.

PubMed

Orlowska-Kowalska, Teresa; Kaminski, Marcin

2014-01-01

The paper deals with the implementation of optimized neural networks (NNs) for state variable estimation of the drive system with an elastic joint. The signals estimated by NNs are used in the control structure with a state-space controller and additional feedbacks from the shaft torque and the load speed. High estimation quality is very important for the correct operation of a closed-loop system. The precision of state variables estimation depends on the generalization properties of NNs. A short review of optimization methods of the NN is presented. Two techniques typical for regularization and pruning methods are described and tested in detail: the Bayesian regularization and the Optimal Brain Damage methods. Simulation results show good precision of both optimized neural estimators for a wide range of changes of the load speed and the load torque, not only for nominal but also changed parameters of the drive system. The simulation results are verified in a laboratory setup.

Seasonal Variability in Regional Ice Flow Due to Meltwater Injection Into the Shear Margins of Jakobshavn Isbræ

NASA Astrophysics Data System (ADS)

Cavanagh, J. P.; Lampkin, D. J.; Moon, T.

2017-12-01

The impact of meltwater injection into the shear margins of Jakobshavn Isbræ via drainage from water-filled crevasses on ice flow is examined. We use Landsat-8 Operational Land Imager panchromatic, high-resolution imagery to monitor the spatiotemporal variability of seven water-filled crevasse ponds during the summers of 2013 to 2015. The timing of drainage from water-filled crevasses coincides with an increase of 2 to 20% in measured ice velocity beyond Jakobshavn Isbræ shear margins, which we define as extramarginal ice velocity. Some water-filled crevasse groups demonstrate multiple drainage events within a single melt season. Numerical simulations show that hydrologic shear weakening due to water-filled crevasse drainage can accelerate extramarginal flow by as much as 35% within 10 km of the margins and enhance mass flux through the shear margins by 12%. This work demonstrates a novel mechanism through which surface melt can influence regional ice flow.

Mediators of Change in Psychosocial Interventions for Cancer Patients: A Systematic Review

PubMed Central

Moyer, Anne; Goldenberg, Matthew; Hall, Matthew A.; Knapp-Oliver, Sarah K.; Sohl, Stephanie J.; Sarma, Elizabeth A.; Schneider, Stefan

2012-01-01

Careful reviews and meta-analyses have made valuable contributions to understanding the efficacy of psychosocial interventions for cancer patients. An important next step is to determine the mediators that explain the influence of efficacious interventions on outcomes. This systematic review summarizes tests of mediating variables from twenty-two projects conducted from 1989–2010. Although all authors provided some type of rationale for considering particular mediating relationships, the investigations varied widely with respect to the extent to which formal theoretical constructs were tested, the type and goals of the interventions studied, and the broad types of outcomes and potential mediators examined. Although there was some evidence supporting selected mediating relationships, with positive findings often found when mediating variables represented behaviors targeted by an intervention, the findings were mixed. Expanding the focus of research to include mechanisms in psychosocial oncology intervention research is necessary for providing a unified picture of how mediating relationships may be operating in this field. PMID:22873734

Working memory capacity and recall from long-term memory: Examining the influences of encoding strategies, study time allocation, search efficiency, and monitoring abilities.

PubMed

Unsworth, Nash

2016-01-01

The relation between working memory capacity (WMC) and recall from long-term memory (LTM) was examined in the current study. Participants performed multiple measures of delayed free recall varying in presentation duration and self-reported their strategy usage after each task. Participants also performed multiple measures of WMC. The results suggested that WMC and LTM recall were related, and part of this relation was due to effective strategy use. However, adaptive changes in strategy use and study time allocation were not related to WMC. Examining multiple variables with structural equation modeling suggested that the relation between WMC and LTM recall was due to variation in effective strategy use, search efficiency, and monitoring abilities. Furthermore, all variables were shown to account for individual differences in LTM recall. These results suggest that the relation between WMC and recall from LTM is due to multiple strategic factors operating at both encoding and retrieval. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

A system for comparison of boring parameters of mini-HDD machines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gunsaulis, F.R.

A system has been developed to accurately evaluate changes in performance of a mini-horizontal directional drilling (HDD) system in the backreaming/pullback portion of a bore as the parameters influencing the backream are changed. Parameters incorporated in the study include spindle rotation rate, rate of pull, fluid flow rate, and backreamer design. The boring system is able to run at variable, operator-determined rates of spindle rotation and pullback speed utilizing electronic feedback controls for regulation. Spindle torque and pullback force are continuously measured and recorded giving an indication of the performance of the unit. A method has also been developed tomore » measure the pull load on the installed service line to determine the effect of the boring parameters on the service line. Variability of soil along the bore path is measured and quantified using a soil sampling system developed for the study. Sample results obtained with the system are included in the report. 2 refs., 5 figs., 2 tabs.« less

Surface laser marking optimization using an experimental design approach

NASA Astrophysics Data System (ADS)

Brihmat-Hamadi, F.; Amara, E. H.; Lavisse, L.; Jouvard, J. M.; Cicala, E.; Kellou, H.

2017-04-01

Laser surface marking is performed on a titanium substrate using a pulsed frequency doubled Nd:YAG laser ( λ= 532 nm, τ pulse=5 ns) to process the substrate surface under normal atmospheric conditions. The aim of the work is to investigate, following experimental and statistical approaches, the correlation between the process parameters and the response variables (output), using a Design of Experiment method (DOE): Taguchi methodology and a response surface methodology (RSM). A design is first created using MINTAB program, and then the laser marking process is performed according to the planned design. The response variables; surface roughness and surface reflectance were measured for each sample, and incorporated into the design matrix. The results are then analyzed and the RSM model is developed and verified for predicting the process output for the given set of process parameters values. The analysis shows that the laser beam scanning speed is the most influential operating factor followed by the laser pumping intensity during marking, while the other factors show complex influences on the objective functions.

Prospective randomized clinical trial of a change in gastric emptying and nutritional status after a pylorus-preserving pancreaticoduodenectomy: comparison between an antecolic and a vertical retrocolic duodenojejunostomy.

PubMed

Imamura, Naoya; Chijiiwa, Kazuo; Ohuchida, Jiro; Hiyoshi, Masahide; Nagano, Motoaki; Otani, Kazuhiro; Kondo, Kazuhiro

2014-04-01

Although an antecolic duodenojejunostomy was reported to reduce post-operative delayed gastric emptying (DGE) compared with a retrocolic duodenojejunostomy after a pylorus-preserving pancreaticoduodenectomy (PPPD), the long-term effects of these procedures have rarely been studied. The aim of this prospective, randomized, clinical trial was to investigate the influence of the reconstruction route on post-operative gastric emptying and nutrition. Reconstruction was performed in 116 patients with an antecolic duodenojejunostomy (A group, n = 58) or a vertical retrocolic duodenojejunostomy (VR group, n = 58). Post-operative complications, including DGE, gastric emptying variables assessed by (13) C-acetate breath test and nutrition, were compared between the two groups for 1 year post-operatively. The incidence of DGE was not significantly different between the procedures (A group: 12.1%; VR group: 20.7%, P = 0.316). At post-operative month 1, gastric emptying was prolonged in the VR versus the A group but not significantly so. At post-operative month 6, gastric emptying was accelerated significantly in the A versus the VR group. Post-operative weight recovery was significantly better in the VR versus the A group at post-operative month 12 (percentage of pre-operative weight, A group: 93.8 ± 1.2%; VR group: 98.5 ± 1.3%, P = 0.015). A vertical retrocolic duodenojejunostomy was an acceptable procedure for the lower incidence of DGE and may contribute to better weight gain affected by moderate gastric emptying. © 2013 International Hepato-Pancreato-Biliary Association.

Post-operative course of coronary artery bypass surgery patients who pre-donate autologous blood.

PubMed

Jovin, Ion S; Stelzig, Georg; Strelitz, Joachim C; Taborski, Uwe; Jovin, Angelika; Heidinger, Kathrin; Klövekorn, Wolf-Peter; Müller-Berghaus, Gert

2003-12-01

Pre-operative autologous blood donation is used to reduce the need of allogeneic blood in patients undergoing coronary bypass surgery operations, but it is not clear what impact the blood donation has on the post-operative course of these patients. We studied the post-operative course of 210 patients who pre-donated autologous blood before their coronary bypass operation (donors) and of 67 patients who were eligible to pre-donate but did not (controls). The clinical variables and the technical operative parameters of the patients in the two groups were similar. There was no significant difference between the duration of assisted ventilation post-operatively (756 +/- 197 vs. 802 +/- 395 min; P=0.54) or length of stay in the intensive care unit (1.8 +/- 1.1 vs. 1.7 +/- 0.9 days; P=0.52) of the two groups. The number of autologous units of packed red cells and of fresh frozen plasma (FFP) received by the donors was significantly higher than the number of units of allogeneic packed red cells (1.5 +/- 0.9 vs. 0.3 +/- 0.9; P=0.001) and the units of homologous FFP received by the controls (2.3 +/- 0.8 vs. 0.6 +/- 1; P=0.001). We found no evidence that autologous blood donation exerted a negative influence on the post-operative course of patients undergoing coronary bypass surgery. Patients who pre-donated blood received no allogeneic blood products, but the number of autologous blood products received by donors was higher than the number of blood products received by patients who did not pre-donate.

Prospective randomized clinical trial of a change in gastric emptying and nutritional status after a pylorus-preserving pancreaticoduodenectomy: comparison between an antecolic and a vertical retrocolic duodenojejunostomy

PubMed Central

Imamura, Naoya; Chijiiwa, Kazuo; Ohuchida, Jiro; Hiyoshi, Masahide; Nagano, Motoaki; Otani, Kazuhiro; Kondo, Kazuhiro

2014-01-01

Background Although an antecolic duodenojejunostomy was reported to reduce post-operative delayed gastric emptying (DGE) compared with a retrocolic duodenojejunostomy after a pylorus-preserving pancreaticoduodenectomy (PPPD), the long-term effects of these procedures have rarely been studied. The aim of this prospective, randomized, clinical trial was to investigate the influence of the reconstruction route on post-operative gastric emptying and nutrition. Methods Reconstruction was performed in 116 patients with an antecolic duodenojejunostomy (A group, n = 58) or a vertical retrocolic duodenojejunostomy (VR group, n = 58). Post-operative complications, including DGE, gastric emptying variables assessed by 13C-acetate breath test and nutrition, were compared between the two groups for 1 year post-operatively. Results The incidence of DGE was not significantly different between the procedures (A group: 12.1%; VR group: 20.7%, P = 0.316). At post-operative month 1, gastric emptying was prolonged in the VR versus the A group but not significantly so. At post-operative month 6, gastric emptying was accelerated significantly in the A versus the VR group. Post-operative weight recovery was significantly better in the VR versus the A group at post-operative month 12 (percentage of pre-operative weight, A group: 93.8 ± 1.2%; VR group: 98.5 ± 1.3%, P = 0.015). Conclusions A vertical retrocolic duodenojejunostomy was an acceptable procedure for the lower incidence of DGE and may contribute to better weight gain affected by moderate gastric emptying. PMID:23991719

Method for assessing motor insulation on operating motors

DOEpatents

Kueck, J.D.; Otaduy, P.J.

1997-03-18

A method for monitoring the condition of electrical-motor-driven devices is disclosed. The method is achieved by monitoring electrical variables associated with the functioning of an operating motor, applying these electrical variables to a three phase equivalent circuit and determining non-symmetrical faults in the operating motor based upon symmetrical components analysis techniques. 15 figs.

Foundations of Effective Influence Operations: A Framework for Enhancing Army Capabilities

DTIC Science & Technology

2009-01-01

interesting approaches we came across in our survey of social science approaches that might be suitable for supporting influence operations. In many...planning, conducting, and assessing the impact of influence operations on attitudes and behaviors. The approach is based on survey instruments that...second to latitude. Influencing Individuals 21 To illustrate, Figure 2.1 presents, in a three-dimensional form, the results from a Galileo survey

Predictors of Help-Seeking Intentions in Operation Enduring Freedom and Operation Iraqi Freedom Veterans and Service Members.

PubMed

Porcari, Carole; Koch, Ellen I; Rauch, Sheila A M; Hoodin, Flora; Ellison, Grant; McSweeney, Lauren

2017-05-01

Despite significant numbers of Afghanistan and Iraqi veterans and service members who report symptoms of posttraumatic stress disorder, depression, anxiety, and substance abuse, the majority do not seek help for these problems. A better understanding of the help-seeking process might aid providers and administrators in outreach and provision of services for those who need them. Past research has shown several variables that influence an individual's help-seeking behavior: demographic variables, the nature and severity of a mental health problem, and psychological variables. The three goals of the study were to determine which variables predicted help-seeking intentions from various sources for a psychological problem, identify barriers to help seeking, and identify sources of help sought in the past year. All Operation Enduring Freedom and Operation Iraqi Freedom veterans and service members registered with a Midwestern VA Healthcare System between 2001 and 2007 received a letter requesting participation in an Internet-based survey. Participants completed nine questionnaires regarding their current physical and psychological health, social support, self-efficacy, public and self-stigma, and barriers to seeking help for a psychological problem. In addition, patterns of help seeking from informal (i.e., partner/spouse, family, friends) and formal (i.e., physician, psychiatrist, or psychologist, either from Veterans Affairs [VA] or the private sector) sources of help were examined. Results from the linear regression model including all formal and informal sources of help indicated a significant model fit with attitudes toward psychotherapy, social support, and current mental health status as significant coefficients. Of note, attitudes toward psychotherapy were a significant coefficient in all help-seeking models; stigma was a significant coefficient with formal and VA sources, and social support was found to be a significant predictor with informal sources. Documentation of a mental health problem on one's record was found to be a significant barrier to help seeking and participants indicated they would most likely seek help in the next year from their partner/spouse, family, or friends versus formal VA or non-VA sources. This is one of the first studies to examine attitudes toward psychotherapy as contributing to help-seeking intentions of veterans and service members and results provide strong support for inclusion of this variable in future studies in addition to social support and stigma. Limitations of the study are discussed as well as suggestions for future research. It is our hope that findings from this study may inform administrators and providers regarding assessment, outreach, and program development for our country's veterans and service members. Reprint & Copyright © 2017 Association of Military Surgeons of the U.S.

Variable density management in riparian reserves: lessons learned from an operational study in managed forests of western Oregon, USA.

Treesearch

Samuel Chan; Paul Anderson; John Cissel; Larry Lateen; Charley Thompson

2004-01-01

A large-scale operational study has been undertaken to investigate variable density management in conjunction with riparian buffers as a means to accelerate development of late-seral habitat, facilitate rare species management, and maintain riparian functions in 40-70 year-old headwater forests in western Oregon, USA. Upland variable retention treatments include...

Increasing Vocal Variability in Children with Autism Using a Lag Schedule of Reinforcement

ERIC Educational Resources Information Center

Esch, John W.; Esch, Barbara E.; Love, Jessa R.

2009-01-01

Variability has been demonstrated to be an operant dimension of behavior (Neuringer, 2002; Page & Neuringer, 1985). Recently, lag schedules have been used to demonstrate operant variability of verbal behavior in persons with a diagnosis of autism (e.g., Lee, McComas, & Jawor, 2002). The current study evaluated the effects of a Lag 1 schedule on…

Population variability in animal health: Influence on dose-exposure-response relationships: Part II: Modelling and simulation.

PubMed

Martinez, Marilyn N; Gehring, Ronette; Mochel, Jonathan P; Pade, Devendra; Pelligand, Ludovic

2018-05-28

During the 2017 Biennial meeting, the American Academy of Veterinary Pharmacology and Therapeutics hosted a 1-day session on the influence of population variability on dose-exposure-response relationships. In Part I, we highlighted some of the sources of population variability. Part II provides a summary of discussions on modelling and simulation tools that utilize existing pharmacokinetic data, can integrate drug physicochemical characteristics with species physiological characteristics and dosing information or that combine observed with predicted and in vitro information to explore and describe sources of variability that may influence the safe and effective use of veterinary pharmaceuticals. © 2018 John Wiley & Sons Ltd. This article has been contributed to by US Government employees and their work is in the public domain in the USA.

Parameterisation of non-homogeneities in buried object detection by means of thermography

NASA Astrophysics Data System (ADS)

Stepanić, Josip; Malinovec, Marina; Švaić, Srećko; Krstelj, Vjera

2004-05-01

Landmines and their natural environment form a system of complex dynamics with variable characteristics. A manifestation of that complexity within the context of thermography-based landmines detection is excessive noise in thermograms. That has severely suppressed application of thermography in landmines detection for the purposes of humanitarian demining. (To be differentiated from military demining and demining for military operations other than war [Land Mine Detection DOD's Research Program Needs a Comprehensive Evaluation Strategy, US GAO Report, GAO-01 239, 2001; International Mine Action Standards, Chapter 4.--Glossary. Available at: < http://www.mineactionstandards.org/IMAS_archive/Final/04.10.pdf>].) The discrepancy between the existing role and the actual potential of thermography in humanitarian demining motivated systematic approach to sources of noise in thermograms of buried objects. These sources are variations in mine orientation relative to soil normal, which modify the shape of mine signature on thermograms, as well as non-homogeneities in soil and vegetation layer above the mine, which modify the overall quality of thermograms. This paper analyses the influence of variable mines, and more generally the influence of axially symmetric buried object orientation on the quality of its signature on thermograms. The following two angles have been extracted to serve as parameters describing variation in orientation: (i) θ--angle between the local vertical axis and mine symmetry axis and (ii) ψ--angle between local vertical axis and soil surface normal. Their influence is compared to the influence of (iii) d--the object depth change, which serves as control parameter. The influences are quantified and ranked within a statistically planned experiment. The analysis has proved that among the parameters listed, the most influential one is statistical interaction dψ, followed with the statistical interaction dθ. According to statistical tests, these two combinations are considered the most significant influences. The results show that the currently applied analysis of thermography in humanitarian demining must be broadened by the inclusion of the variations in mine orientation, otherwise a decrease in the probability of mine detection, due to the presence of a systematic error, occurs.

Vegetation Interaction Enhances Interdecadal Climate Variability in the Sahel

NASA Technical Reports Server (NTRS)

Zeng, Ning; Neelin, J. David; Lau, William K.-M.

1999-01-01

The role of naturally varying vegetation in influencing the climate variability in the Sahel is explored in a coupled atmosphere-land-vegetation model. The Sahel rainfall variability is influenced by sea surface temperature (SST) variations in the oceans. Land-surface feedback is found to increase this variability both on interannual and interdecadal time scales. Interactive vegetation enhances the interdecadal variation significantly, but can reduce year to year variability due to a phase lag introduced by the relatively slow vegetation adjustment time. Variations in vegetation accompany the changes in rainfall, in particular, the multi-decadal drying trend from the 1950s to the 80s.

Subwavelength grating enabled on-chip ultra-compact optical true time delay line

PubMed Central

Wang, Junjia; Ashrafi, Reza; Adams, Rhys; Glesk, Ivan; Gasulla, Ivana; Capmany, José; Chen, Lawrence R.

2016-01-01

An optical true time delay line (OTTDL) is a basic photonic building block that enables many microwave photonic and optical processing operations. The conventional design for an integrated OTTDL that is based on spatial diversity uses a length-variable waveguide array to create the optical time delays, which can introduce complexities in the integrated circuit design. Here we report the first ever demonstration of an integrated index-variable OTTDL that exploits spatial diversity in an equal length waveguide array. The approach uses subwavelength grating waveguides in silicon-on-insulator (SOI), which enables the realization of OTTDLs having a simple geometry and that occupy a compact chip area. Moreover, compared to conventional wavelength-variable delay lines with a few THz operation bandwidth, our index-variable OTTDL has an extremely broad operation bandwidth practically exceeding several tens of THz, which supports operation for various input optical signals with broad ranges of central wavelength and bandwidth. PMID:27457024

Subwavelength grating enabled on-chip ultra-compact optical true time delay line.

PubMed

Wang, Junjia; Ashrafi, Reza; Adams, Rhys; Glesk, Ivan; Gasulla, Ivana; Capmany, José; Chen, Lawrence R

2016-07-26

An optical true time delay line (OTTDL) is a basic photonic building block that enables many microwave photonic and optical processing operations. The conventional design for an integrated OTTDL that is based on spatial diversity uses a length-variable waveguide array to create the optical time delays, which can introduce complexities in the integrated circuit design. Here we report the first ever demonstration of an integrated index-variable OTTDL that exploits spatial diversity in an equal length waveguide array. The approach uses subwavelength grating waveguides in silicon-on-insulator (SOI), which enables the realization of OTTDLs having a simple geometry and that occupy a compact chip area. Moreover, compared to conventional wavelength-variable delay lines with a few THz operation bandwidth, our index-variable OTTDL has an extremely broad operation bandwidth practically exceeding several tens of THz, which supports operation for various input optical signals with broad ranges of central wavelength and bandwidth.

Electric Motors Maintenance Planning From Its Operating Variables

NASA Astrophysics Data System (ADS)

Rodrigues, Francisco; Fonseca, Inácio; Farinha, José Torres; Ferreira, Luís; Galar, Diego

2017-09-01

The maintenance planning corresponds to an approach that seeks to maximize the availability of equipment and, consequently, increase the levels of competitiveness of companies by increasing production times. This paper presents a maintenance planning based on operating variables (number of hours worked, duty cycles, number of revolutions) to maximizing the availability of operation of electrical motors. The reading of the operating variables and its sampling is done based on predetermined sampling cycles and subsequently is made the data analysis through time series algorithms aiming to launch work orders before reaching the variables limit values. This approach is supported by tools and technologies such as logical applications that enable a graphical user interface for access to relevant information about their Physical Asset HMI (Human Machine Interface), including the control and supervision by acquisition through SCADA (Supervisory Control And data acquisition) data, also including the communication protocols among different logical applications.

Consideration of What May Influence Student Outcomes on Alternate Assessment.

ERIC Educational Resources Information Center

Browder, Diane M.; Fallin, Kathy; Davis, Stephanie; Karvonen, Meagan

2003-01-01

This article describes variables that may influence alternate assessment outcomes for students with disabilities and offers recommendations to enhance student achievement. These variables include technical quality, curriculum access, data collection, instructional effectiveness, risk factors, and resources allocated to instruction. Two of four…

Crossing safety barriers: influence of children's morphological and functional variables.

PubMed

Cordovil, Rita; Vieira, Filomena; Barreiros, João

2012-05-01

Thirty-three children between 3 and 6 years of age were asked to climb four different types of safety barriers. Morphological and functional variables of the children, which were expected to influence climbing or passing through skills, were collected. The influence of those variables on children's success rate and time to cross was tested. No barrier offered a total restraining efficacy. The horizontal bars barrier was crossed by 97% of the children. In the group of children that succeeded in crossing the four barriers, mean time to cross the most difficult barrier was 15 s. Age was the best predictor for success in crossing most barriers but morphology and strength were important predictors of time to cross. The influence of anthropometric variables in time to cross was dependent upon the characteristics of the barrier. A good design of safety barriers should consider children's age, morphology and strength. Copyright © 2011 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Simulation of changes in heavy metal contamination in farmland soils of a typical manufacturing center through logistic-based cellular automata modeling.

PubMed

Qiu, Menglong; Wang, Qi; Li, Fangbai; Chen, Junjian; Yang, Guoyi; Liu, Liming

2016-01-01

A customized logistic-based cellular automata (CA) model was developed to simulate changes in heavy metal contamination (HMC) in farmland soils of Dongguan, a manufacturing center in Southern China, and to discover the relationship between HMC and related explanatory variables (continuous and categorical). The model was calibrated through the simulation and validation of HMC in 2012. Thereafter, the model was implemented for the scenario simulation of development alternatives for HMC in 2022. The HMC in 2002 and 2012 was determined through soil tests and cokriging. Continuous variables were divided into two groups by odds ratios. Positive variables (odds ratios >1) included the Nemerow synthetic pollution index in 2002, linear drainage density, distance from the city center, distance from the railway, slope, and secondary industrial output per unit of land. Negative variables (odds ratios <1) included elevation, distance from the road, distance from the key polluting enterprises, distance from the town center, soil pH, and distance from bodies of water. Categorical variables, including soil type, parent material type, organic content grade, and land use type, also significantly influenced HMC according to Wald statistics. The relative operating characteristic and kappa coefficients were 0.91 and 0.64, respectively, which proved the validity and accuracy of the model. The scenario simulation shows that the government should not only implement stricter environmental regulation but also strengthen the remediation of the current polluted area to effectively mitigate HMC.

The intention to continue nursing: work variables affecting three nurse generations in Australia.

PubMed

Shacklock, Kate; Brunetto, Yvonne

2012-01-01

The aims of the study were to examine how seven variables impacted upon the intention of hospital nurses to continue working as nurses and to investigate whether there are generational differences in these impacts. There is a critical shortage of trained nurses working as nurses in Australia, as in many other Organisation for Economic Co-operation and Development member countries. The retention of nurses has been examined from the traditional management perspectives; however, this paper presents a different approach (Meaning of Working theory). A self-report survey of 900 nurses employed across four states of Australia was completed in 2008. The sample was hospital nurses in Australia from three generational cohorts - Baby Boomers (born in Australia between 1946 and 1964), Generation X (1965-1979) and Generation Y (1980-2000). Six variables were found to influence the combined nurses' intentions to continue working as nurses: work-family conflict, perceptions of autonomy, attachment to work, importance of working to the individual, supervisor-subordinate relationship and interpersonal relationships at work. There were differences in the variables affecting the three generations, but attachment to work was the only common variable across all generations, affecting GenYs the strongest. The shortage of nurses is conceptualized differently in this paper to assist in finding solutions. However, the results varied for the three generations, suggesting the need to tailor different retention strategies to each age group. Implications for management and policy planning are discussed. © 2011 Blackwell Publishing Ltd.

A data mining approach to derive flood-related economic vulnerability of companies

NASA Astrophysics Data System (ADS)

Sieg, Tobias; Kreibich, Heidi; Vogel, Kristin; Merz, Bruno

2017-04-01

The assessment of vulnerability gained more and more attention in flood risk research during the recent years. However, there is still not much knowledge available about flood vulnerability of companies and its influencing factors. This study follows the natural sciences concept which defines vulnerability as the degree of loss to a given element at risk resulting from flooding of a given magnitude. Machine learning algorithms like Random Forests (RFs) are promising approaches, since they consider many influencing variables and as such allow for a detailed assessment of flood vulnerability. Only these variables which are meaningful for the differentiation of a certain target variable are used by the derived models. This allows for an identification of relevant damage influencing variables and hence for a more detailed picture of flood vulnerability of companies. This study aims to identify relevant damage influencing variables by means of the variable importance provided by Random Forests. The data sets used are taken from two surveys conducted after the floods in the Elbe and Danube catchments in the years 2002 and 2013 in Germany. Damage to buildings (n = 430), equipment (n = 651) as well as goods and stock (n = 530) are taken into account. The analysis is done for the entire data set as well as for four groups of different company sectors and the corresponding data subsets. Relevant damage influencing variables separated by sector and assets are identified as, for example, the degree of contamination or precautionary measures undertaken before the flood event. The results provide insight into the damage processes and improve data-acquisition in future surveys by, for instance, asking specific questions for company sectors and assets.

Climate variation explains a third of global crop yield variability

PubMed Central

Ray, Deepak K.; Gerber, James S.; MacDonald, Graham K.; West, Paul C.

2015-01-01

Many studies have examined the role of mean climate change in agriculture, but an understanding of the influence of inter-annual climate variations on crop yields in different regions remains elusive. We use detailed crop statistics time series for ~13,500 political units to examine how recent climate variability led to variations in maize, rice, wheat and soybean crop yields worldwide. While some areas show no significant influence of climate variability, in substantial areas of the global breadbaskets, >60% of the yield variability can be explained by climate variability. Globally, climate variability accounts for roughly a third (~32–39%) of the observed yield variability. Our study uniquely illustrates spatial patterns in the relationship between climate variability and crop yield variability, highlighting where variations in temperature, precipitation or their interaction explain yield variability. We discuss key drivers for the observed variations to target further research and policy interventions geared towards buffering future crop production from climate variability. PMID:25609225

Key External Influences Affecting Consumers’ Decisions Regarding Food

PubMed Central

Martínez-Ruiz, María Pilar; Gómez-Cantó, Carmen María

2016-01-01

Among the numerous internal and external forces that compete for consumers’ attention in the context in which they buy their food, this paper will seek to provide a review of the most important external influences, such as the variables related to food itself. To this end, in addition to the food attributes traditionally identified in fields such as consumer behavior, it will give special consideration to the classification of food values. Although the influence of these variables on consumer decisions depends on the individual, analyzing them will undoubtedly increase understanding of consumers’ decisions. Additionally, identifying and describing these variables will enable subsequent research on how they influence both consumer behavior and other key outcomes for producers, manufacturers, and retailers in the food industry, such as satisfaction, trust, and loyalty. PMID:27803686

Performance characteristics of LOX-H2, tangential-entry, swirl-coaxial, rocket injectors

NASA Technical Reports Server (NTRS)

Howell, Doug; Petersen, Eric; Clark, Jim

1993-01-01

Development of a high performing swirl-coaxial injector requires an understanding of fundamental performance characteristics. This paper addresses the findings of studies on cold flow atomic characterizations which provided information on the influence of fluid properties and element operating conditions on the produced droplet sprays. These findings are applied to actual rocket conditions. The performance characteristics of swirl-coaxial injection elements under multi-element hot-fire conditions were obtained by analysis of combustion performance data from three separate test series. The injection elements are described and test results are analyzed using multi-variable linear regression. A direct comparison of test results indicated that reduced fuel injection velocity improved injection element performance through improved propellant mixing.

Modeling of industrial stream and resources of machine-building enterpriser complex of wood preparation

NASA Astrophysics Data System (ADS)

Sereda, T. G.; Kostarev, S. N.

2018-03-01

Theoretical bases of linkage of material streams of the machine-building enterprise and the automated system of decision-making are developed. The process of machine-building manufacture is submitted by the existential system. The equation of preservation of movement is based on calculation of volume of manufacture. The basis of resource variables includes capacities and operators of the equipment. Indignations such as a defect and failure are investigated in the existential basis. The equation of a stream of details on a manufacturing route is made. The received analytical expression expresses a condition of a stream of movement of details in view of influence of work of the equipment and traumatism of the personnel.

The research on visual industrial robot which adopts fuzzy PID control algorithm

NASA Astrophysics Data System (ADS)

Feng, Yifei; Lu, Guoping; Yue, Lulin; Jiang, Weifeng; Zhang, Ye

2017-03-01

The control system of six degrees of freedom visual industrial robot based on the control mode of multi-axis motion control cards and PC was researched. For the variable, non-linear characteristics of industrial robot`s servo system, adaptive fuzzy PID controller was adopted. It achieved better control effort. In the vision system, a CCD camera was used to acquire signals and send them to video processing card. After processing, PC controls the six joints` motion by motion control cards. By experiment, manipulator can operate with machine tool and vision system to realize the function of grasp, process and verify. It has influence on the manufacturing of the industrial robot.

Coupled Effects of non-Newtonian Rheology and Aperture Variability on Flow in a Single Fracture

NASA Astrophysics Data System (ADS)

Di Federico, V.; Felisa, G.; Lauriola, I.; Longo, S.

2017-12-01

Modeling of non-Newtonian flow in fractured media is essential in hydraulic fracturing and drilling operations, EOR, environmental remediation, and to understand magma intrusions. An important step in the modeling effort is a detailed understanding of flow in a single fracture, as the fracture aperture is spatially variable. A large bibliography exists on Newtonian and non-Newtonian flow in variable aperture fractures. Ultimately, stochastic or deterministic modeling leads to the flowrate under a given pressure gradient as a function of the parameters describing the aperture variability and the fluid rheology. Typically, analytical or numerical studies are performed adopting a power-law (Oswald-de Waele) model. Yet the power-law model, routinely used e.g. for hydro-fracturing modeling, does not characterize real fluids at low and high shear rates. A more appropriate rheological model is provided by e.g. the four-parameter Carreau constitutive equation, which is in turn approximated by the more tractable truncated power-law model. Moreover, fluids of interest may exhibit yield stress, which requires the Bingham or Herschel-Bulkely model. This study employs different rheological models in the context of flow in variable aperture fractures, with the aim of understanding the coupled effect of rheology and aperture spatial variability with a simplified model. The aperture variation, modeled within a stochastic or deterministic framework, is taken to be one-dimensional and i) perpendicular; ii) parallel to the flow direction; for stochastic modeling, the influence of different distribution functions is examined. Results for the different rheological models are compared with those obtained for the pure power-law. The adoption of the latter model leads to overestimation of the flowrate, more so for large aperture variability. The presence of yield stress also induces significant changes in the resulting flowrate for assigned external pressure gradient.

Affiliation With Antisocial Peers, Susceptibility to Peer Influence, and Antisocial Behavior During the Transition to Adulthood

PubMed Central

Monahan, Kathryn C.; Steinberg, Laurence; Cauffman, Elizabeth

2010-01-01

Developmental theories suggest that affiliation with deviant peers and susceptibility to peer influence are important contributors to adolescent delinquency, but it is unclear how these variables impact antisocial behavior during the transition to adulthood, a period when most delinquent individuals decline in antisocial behavior. Using data from a longitudinal study of 1,354 antisocial youth, the present study examined how individual variation in exposure to deviant peers and resistance to peer influence affect antisocial behavior from middle adolescence into young adulthood (ages 14 to 22 years). Whereas we find evidence that antisocial individuals choose to affiliate with deviant peers, and that affiliating with deviant peers is associated with an individual’s own delinquency, these complementary processes of selection and socialization operate in different developmental periods. In middle adolescence, both selection and socialization serve to make peers similar in antisocial behavior, but from ages 16 to 20 years, only socialization appears to be important. After age 20, the impact of peers on antisocial behavior disappears as individuals become increasingly resistant to peer influence, suggesting that the process of desistance from antisocial behavior may be tied to normative changes in peer relations that occur as individuals mature socially and emotionally. PMID:19899911

Repeatability of diagnostic ultrasonography in the assessment of the equine superficial digital flexor tendon.

PubMed

Pickersgill, C H; Marr, C M; Reid, S W

2001-01-01

A quantitative investigation of the variation that can occur during the course of ultrasonography of the equine superficial digital flexor tendons (SDFT) was undertaken. The aim of this investigation was to use an objective measure, namely the measurement of CSA, to quantify the variability occurring during the course of the ultrasonographic assessment of the equine SDFT. The effects of 3 variables on the CSA measurements were determined. 1) Image acquisition operator (IAc): two different operators undertaking the ultrasonographic examination; 2) image analysis operator (IAn): two different operators undertaking the calculation of CSA values from previously stored images; and 3) analytical equipment (used during CSA measurement) (IEq): the use of 2 different sets of equipment during calculation of CSA values. Tendon cross-sectional area (CSA) measurements were used as the comparative variable of 3 potential sources: interoperator, during image acquisition; interoperator, during CSA measurement; and intraoperator, when using different analytical equipment. Two operators obtained transverse ultrasonographic images from the forelimb SDFTs of 16 National Hunt (NH) Thoroughbred (TB) racehorses, each undertaking analysis of their own and the other operator's images. One operator undertook analysis of their images using 2 sets of equipment. There was no statistically significant difference in the results obtained when different operators undertook image acquisition (P>0.05). At all but the most distal level, there was no significant difference when different equipment was used during analysis (P>0.05). A significant difference (P<0.01) was reported when different operators undertook image analysis, one operator consistently returning larger measurements. Different operators undertaking different stages of an examination can result in significant variability. To reduce confounding during ultrasonographic investigations involving multiple persons, one operator should undertake image analysis, although different operators may undertake image acquisition.

Variable-Period Undulators For Synchrotron Radiation

DOEpatents

Shenoy, Gopal; Lewellen, John; Shu, Deming; Vinokurov, Nikolai

2005-02-22

A new and improved undulator design is provided that enables a variable period length for the production of synchrotron radiation from both medium-energy and high-energy storage rings. The variable period length is achieved using a staggered array of pole pieces made up of high permeability material, permanent magnet material, or an electromagnetic structure. The pole pieces are separated by a variable width space. The sum of the variable width space and the pole width would therefore define the period of the undulator. Features and advantages of the invention include broad photon energy tunability, constant power operation and constant brilliance operation.

Drivers for spatial variability in agricultural soil organic carbon stocks in Germany

NASA Astrophysics Data System (ADS)

Vos, Cora; Don, Axel; Hobley, Eleanor; Prietz, Roland; Heidkamp, Arne; Freibauer, Annette

2017-04-01

Soil organic carbon is one of the largest components of the global carbon cycle. It has recently gained importance in global efforts to mitigate climate change through carbon sequestration. In order to find locations suitable for carbon sequestration, and estimate the sequestration potential, however, it is necessary to understand the factors influencing the high spatial variability of soil organic carbon stocks. Due to numerous interacting factors that influence its dynamics, soil organic carbon stocks are difficult to predict. In the course of the German Agricultural Soil Inventory over 2500 agricultural sites were sampled and their soil organic carbon stocks determined. Data relating to more than 200 potential drivers of SOC stocks were compiled from laboratory measurements, farmer questionnaires and climate stations. The aims of this study were to 1) give an overview of soil organic carbon stocks in Germany's agricultural soils, 2) to quantify and explain the influence of explanatory variables on soil organic carbon stocks. Two different machine learning algorithms were used to identify the most important variables and multiple regression models were used to explore the influence of those variables. Models for predicting carbon stocks in different depth increments between 0-100 cm were developed, explaining up to 62% (validation, 98% calibration) of total variance. Land-use, land-use history, clay content and electrical conductivity were main predictors in the topsoil, while bedrock material, relief and electrical conductivity governed the variability of subsoil carbon stocks. We found 32% of all soils to be deeply anthropogenically transformed. The influence of climate related variables was surprisingly small (≤5% of explained variance), while site variables explained a large share of soil carbon variability (46-100% of explained variance), in particular in the subsoil. Thus, the understanding of SOC dynamics at regional scale requires a thorough description of the variability in soil physical parameters. Agronomic management impact on SOC stocks is important near the soil surface, but is mainly attributable to land-use and not to other management factors on this large regional scale. The importance of historical land-use practices as well as anthropogenic soil transformations to SOC stocks highlights the need for prudent soil management and conservation policies.

Applications of variable speed control for contending with recurrent highway congestion.

DOT National Transportation Integrated Search

2014-07-01

This research project developed vital operational guidelines for design of a variable speed limit (VSL) system and its integrated operations with ramp metering control in contending with recurrent highway congestion. The developed guidelines can serv...

Variable speed generator technology options for wind turbine generators

NASA Technical Reports Server (NTRS)

Lipo, T. A.

1995-01-01

The electrical system options for variable speed operation of a wind turbine generator are treated in this paper. The key operating characteristics of each system are discussed and the major advantages and disadvantages of each are identified

Microbial community structure and dynamics in a pilot-scale submerged membrane bioreactor aerobically treating domestic wastewater under real operation conditions.

PubMed

Molina-Muñoz, M; Poyatos, J M; Sánchez-Peinado, M; Hontoria, E; González-López, J; Rodelas, B

2009-06-15

A pilot scale submerged ultra-filtration membrane bioreactor (MBR) was used for the aerobic treatment of domestic wastewater over 9 months of year 2006 (28th March to 21st December). The MBR was installed at a municipal wastewater facility (EMASAGRA, Granada, Spain) and was fed with real wastewater. The experimental work was divided in 4 stages run under different sets of operation conditions. Operation parameters (total and volatile suspended solids, dissolved oxygen concentration) and environmental variables (temperature, pH, COD and BOD(5) of influent water) were daily monitored. In all the experiments conducted, the MBR generated an effluent of optimal quality complying with the requirements of the European Law (91/271/CEE 1991). A cultivation-independent approach (polymerase chain reaction-temperature gradient gel electrophoresis, PCR-TGGE) was used to analyze changes in the structure of the bacterial communities in the sludge. Cluster analysis of TGGE profiles demonstrated significant differences in community structure related to variations of the operation parameters and environmental factors. Canonical correspondence analysis (CCA) suggested that temperature, hydraulic retention time and concentration of volatile suspended solids were the factors mostly influencing community structure. 23 prominent TGGE bands were successfully reamplified and sequenced, allowing gaining insight into the identities of predominantly present bacterial populations in the sludge. Retrieved partial 16S-rRNA gene sequences were mostly related to the alpha-Proteobacteria, beta-Proteobacteria and gamma-Proteobacteria classes. The community established in the MBR in each of the four stages of operation significantly differed in species composition and the sludge generated displayed dissimilar rates of mineralization, but these differences did not influence the performance of the bioreactor (quality of the permeate). These data indicate that the flexibility of the bacterial community in the sludge and its ability to get adapted to environmental changes play an important role for the stable performance of MBRs.

Key factors associated with postoperative complications in patients undergoing colorectal surgery.

PubMed

Manilich, E; Vogel, J D; Kiran, R P; Church, J M; Seyidova-Khoshknabi, Dilara; Remzi, F H

2013-01-01

Surgical outcomes are determined by complex interactions among a variety of factors including patient characteristics, diagnosis, and type of procedure. The aim of this study was to prioritize the effect and relative importance of the surgeon (in terms of identity of a surgeon and surgeon volume), patient characteristics, and the intraoperative details on complications of colorectal surgery including readmission, reoperation, sepsis, anastomotic leak, small-bowel obstruction, surgical site infection, abscess, need for transfusion, and portal and deep vein thrombosis. This study uses a novel classification methodology to measure the influence of various risk factors on postoperative complications in a large outcomes database. Using prospectively collected information from the departmental outcomes database from 2010 to 2011, we examined the records of 3552 patients who underwent colorectal surgery. Instead of traditional statistical methods, we used a family of 7000 bootstrap classification models to examine and quantify the impact of various factors on the most common serious surgical complications. For each complication, an ensemble of multivariate classification models was designed to determine the relative importance of potential factors that may influence outcomes of surgery. This is a new technique for analyzing outcomes data that produces more accurate results and a more reliable ranking of study variables in order of their importance in producing complications. Patients who underwent colorectal surgery in 2010 and 2011 were included. This study was conducted at a tertiary referral department at a major medical center. Postoperative complications were the primary outcomes measured. Factors sorted themselves into 2 groups: a highly important group (operative time, BMI, age, identity of the surgeon, type of surgery) and a group of low importance (sex, comorbidity, laparoscopy, and emergency). ASA score and diagnosis were of intermediate importance. The outcomes most influenced by variations in the highly important factors included readmission, transfusion, surgical site infection, and abscesses. This study was limited by the use of data from a single tertiary referral department at a major medical center. Body mass index, operative time, and the surgeon who performed the operation are the 3 most important factors influencing readmission rates, rates of transfusions, and surgical site infection. Identification of these contributing factors can help minimize complications.

Hydrological deformation signals in karst systems: new evidence from the European Alps

NASA Astrophysics Data System (ADS)

Serpelloni, E.; Pintori, F.; Gualandi, A.; Scoccimarro, E.; Cavaliere, A.; Anderlini, L.; Belardinelli, M. E.; Todesco, M.

2017-12-01

The influence of rainfall on crustal deformation has been described at local scales, using tilt and strain meters, in several tectonic settings. However, the literature on the spatial extent of rainfall-induced deformation is still scarce. We analyzed 10 years of displacement time-series from 150 continuous GPS stations operating across the broad zone of deformation accommodating the N-S Adria-Eurasia convergence and the E-ward escape of the Eastern Alps toward the Pannonian basin. We applied a blind-source-separation algorithm based on a variational Bayesian Independent Component Analysis method to the de-trended time-series, being able to characterize the temporal and spatial features of several deformation signals. The most important ones are a common mode annual signal, with spatially uniform response in the vertical and horizontal components and a time-variable, non-cyclic, signal characterized by a spatially variable response in the horizontal components, with stations moving (up to 8 mm) in the opposite directions, reversing the sense of movement in time. This implies a succession of extensional/compressional strains, with variable amplitudes through time, oriented normal to rock fractures in karst areas. While seasonal displacements in the vertical component (with an average amplitude of 4 mm over the study area) are satisfactorily reproduced by surface hydrological loading, estimated from global assimilation models, the non seasonal signal is associated with groundwater flow in karst systems, and is mainly influencing the horizontal component. The temporal evolution of this deformation signal is correlated with cumulated precipitation values over periods of 200-300 days. This horizontal deformation can be explained by pressure changes associated with variable water levels within vertical fractures in the vadose zones of karst systems, and the water level changes required to open or close these fractures are consistent with the fluctuations of precipitation and with the dynamics of karst systems.

Factors predictive of the onset and duration of action of local anesthesia in mandibular third-molar surgery: a prospective study.

PubMed

Al-Shayyab, Mohammad H; Baqain, Zaid H

2018-04-01

The aim of this study was to assess the influence of patients' and surgical variables on the onset and duration of action of local anesthesia (LA) in mandibular third-molar (M3) surgery. Patients scheduled for mandibular M3 surgery were considered for inclusion in this prospective cohort study. Patients' and surgical variables were recorded. Two per cent (2%) lidocaine with 1:100,000 epinephrine was used to block the nerves for extraction of mandibular M3. Then, the onset of action and duration of LA were monitored. Univariate analysis and multivariate regression analysis were used to analyze the data. The final cohort included 88 subjects (32 men and 56 women; mean age ± SD = 29.3 ± 12.3 yr). With univariate analysis, age, gender, body mass index (BMI), smoking quantity and duration, operation time, and 'volume of local anesthetic needed' significantly influenced the onset of action and duration of LA. Multivariate regression revealed that age and smoking quantity were the only statistically significant predictors of the onset of action of LA, whereas age, smoking quantity, and 'volume of local anesthetic needed' were the only statistically significant predictors of duration of LA. Further studies are recommended to uncover other predictors of the onset of action and duration of LA. © 2018 Eur J Oral Sci.

Mineral Ecology: Surface Specific Colonization and Geochemical Drivers of Biofilm Accumulation, Composition, and Phylogeny

PubMed Central

Jones, Aaron A.; Bennett, Philip C.

2017-01-01

This study tests the hypothesis that surface composition influences microbial community structure and growth of biofilms. We used laboratory biofilm reactors (inoculated with a diverse subsurface community) to explore the phylogenetic and taxonomic variability in microbial communities as a function of surface type (carbonate, silicate, aluminosilicate), media pH, and carbon and phosphate availability. Using high-throughput pyrosequencing, we found that surface type significantly controlled ~70–90% of the variance in phylogenetic diversity regardless of environmental pressures. Consistent patterns also emerged in the taxonomy of specific guilds (sulfur-oxidizers/reducers, Gram-positives, acidophiles) due to variations in media chemistry. Media phosphate availability was a key property associated with variation in phylogeny and taxonomy of whole reactors and was negatively correlated with biofilm accumulation and α-diversity (species richness and evenness). However, mineral-bound phosphate limitations were correlated with less biofilm. Carbon added to the media was correlated with a significant increase in biofilm accumulation and overall α-diversity. Additionally, planktonic communities were phylogenetically distant from those in biofilms. All treatments harbored structurally (taxonomically and phylogenetically) distinct microbial communities. Selective advantages within each treatment encouraged growth and revealed the presence of hundreds of additional operational taxonomix units (OTU), representing distinct consortiums of microorganisms. Ultimately, these results provide evidence that mineral/rock composition significantly influences microbial community structure, diversity, membership, phylogenetic variability, and biofilm growth in subsurface communities. PMID:28400754

Influence of El Niño Southern Oscillation on global hydropower production

NASA Astrophysics Data System (ADS)

Ng, Jia Yi; Turner, Sean W. D.; Galelli, Stefano

2017-03-01

El Niño Southern Oscillation (ENSO) strongly influences the global climate system, affecting hydrology in many of the world’s river basins. This raises the prospect of ENSO-driven variability in global and regional hydroelectric power generation. Here we study these effects by generating time series of power production for 1593 hydropower dams, which collectively represent more than half of the world’s existing installed hydropower capacity. The time series are generated by forcing a detailed dam model with monthly-resolution, 20th century inflows—the model includes plant specifications, storage dynamics and realistic operating schemes, and runs irrespectively of the dam construction year. More than one third of simulated dams exhibit statistically significant annual energy production anomalies in at least one of the two ENSO phases of El Niño and La Niña. For most dams, the variability of relative anomalies in power production tends to be less than that of the forcing inflows—a consequence of dam design specifications, namely maximum turbine release rate and reservoir storage, which allows inflows to accumulate for power generation in subsequent dry years. Production is affected most prominently in Northwest United States, South America, Central America, the Iberian Peninsula, Southeast Asia and Southeast Australia. When aggregated globally, positive and negative energy production anomalies effectively cancel each other out, resulting in a weak and statistically insignificant net global anomaly for both ENSO phases.

Analysis of operating reserve demand curves in power system operations in the presence of variable generation

DOE PAGES

Krad, Ibrahim; Gao, David Wenzhong; Ela, Erik; ...

2017-06-07

The electric power industry landscape is continually evolving. As emerging technologies such as wind and solar generating systems become more cost effective, traditional power system operating strategies will need to be re-evaluated. The presence of wind and solar generation (commonly referred to as variable generation or VG) can increase variability and uncertainty in the net-load profile. One mechanism to mitigate this issue is to schedule and dispatch additional operating reserves. These operating reserves aim to ensure that there is enough capacity online in the system to account for the increased variability and uncertainty occurring at finer temporal resolutions. A newmore » operating reserve strategy, referred to as flexibility reserve, has been introduced in some regions. A similar implementation is explored in this study, and its implications on power system operations are analyzed. Results show that flexibility reserve products can improve economic metrics, particularly in significantly reducing the number of scarcity pricing events, with minimal impacts on reliability metrics and production costs. Furthermore, the production costs increased due to increased VG curtailment - i.e. including the flexible ramping product in the commitment of excess thermal capacity that needed to remain online at the expense of VG output.« less

Analysis of operating reserve demand curves in power system operations in the presence of variable generation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krad, Ibrahim; Gao, David Wenzhong; Ela, Erik

The electric power industry landscape is continually evolving. As emerging technologies such as wind and solar generating systems become more cost effective, traditional power system operating strategies will need to be re-evaluated. The presence of wind and solar generation (commonly referred to as variable generation or VG) can increase variability and uncertainty in the net-load profile. One mechanism to mitigate this issue is to schedule and dispatch additional operating reserves. These operating reserves aim to ensure that there is enough capacity online in the system to account for the increased variability and uncertainty occurring at finer temporal resolutions. A newmore » operating reserve strategy, referred to as flexibility reserve, has been introduced in some regions. A similar implementation is explored in this study, and its implications on power system operations are analyzed. Results show that flexibility reserve products can improve economic metrics, particularly in significantly reducing the number of scarcity pricing events, with minimal impacts on reliability metrics and production costs. Furthermore, the production costs increased due to increased VG curtailment - i.e. including the flexible ramping product in the commitment of excess thermal capacity that needed to remain online at the expense of VG output.« less

Power Supply for Variable Frequency Induction Heating Using MERS Soft-Switching High Frequency Inverter

NASA Astrophysics Data System (ADS)

Isobe, Takanori; Kitahara, Tadayuki; Fukutani, Kazuhiko; Shimada, Ryuichi

Variable frequency induction heating has great potential for industrial heating applications due to the possibility of achieving heating distribution control; however, large-scale induction heating with variable frequency has not yet been introduced for practical use. This paper proposes a high frequency soft-switching inverter for induction heating that can achieve variable frequency operation. One challenge of variable frequency induction heating is increasing power electronics ratings. This paper indicates that its current source type dc-link configuration and soft-switching characteristics can make it possible to build a large-scale system with variable frequency capability. A 90-kVA 150-1000Hz variable frequency experimental power supply for steel strip induction heating was developed. Experiments confirmed the feasibility of variable frequency induction heating with proposed converter and the advantages of variable frequency operation.

Laboratory Measurements of Biomass Cook-stove Emissions Aged in an Oxidation Flow Reactor: Influence of Combustion and Aging Conditions on Aerosols

NASA Astrophysics Data System (ADS)

Grieshop, A. P.; Reece, S. M.; Sinha, A.; Wathore, R.

2016-12-01

Combustion in rudimentary and improved cook-stoves used by billions in developing countries can be a regionally dominant contributor to black carbon (BC), primary organic aerosols (POA) and precursors for secondary organic aerosol (SOA). Recent studies suggest that SOA formed during photo-oxidation of primary emissions from biomass burning may make important contribution to its atmospheric impacts. However, the extent to which stove type and operating conditions affect the amount, composition and characteristics of SOA formed from the aging of cookstoves emissions is still largely undetermined. Here we present results from experiments with a field portable oxidation flow reactor (F-OFR) designed to assess aging of cook-stove emissions in both laboratory and field settings. Laboratory tests results are used to compare the quantity and properties of fresh and aged emissions from a traditional open fire and twp alternative stove designs operated on the standard and alternate testing protocols. Diluted cookstove emissions were exposed to a range of oxidant concentrations in the F-OFR. Primary emissions were aged both on-line, to study the influence of combustion variability, and sampled from batched emissions in a smog chamber to examine different aging conditions. Data from real-time particle- and gas-phase instruments and integrated filter samples were collected up and down stream of the OFR. The properties of primary emissions vary strongly with stove type and combustion conditions (e.g. smoldering versus flaming). Experiments aging diluted biomass emissions from distinct phases of stove operation (smoldering and flaming) showed peak SOA production for both phases occurred between 3 and 6 equivalent days of aging with slightly greater production observed in flaming phase emissions. Changing combustion conditions had a stronger influence than aging on POA+SOA `emission factors'. Aerosol Chemical Speciation Monitor data show a substantial evolution of aerosol composition with aging. These results highlight the importance of both stoves' operating conditions and aging on composition and characteristics of emissions, which have important implications for regional air quality and climate forcing.

A Comprehensive Comparison of Current Operating Reserve Methodologies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krad, Ibrahim; Ibanez, Eduardo; Gao, Wenzhong

Electric power systems are currently experiencing a paradigm shift from a traditionally static system to a system that is becoming increasingly more dynamic and variable. Emerging technologies are forcing power system operators to adapt to their performance characteristics. These technologies, such as distributed generation and energy storage systems, have changed the traditional idea of a distribution system with power flowing in one direction into a distribution system with bidirectional flows. Variable generation, in the form of wind and solar generation, also increases the variability and uncertainty in the system. As such, power system operators are revisiting the ways in whichmore » they treat this evolving power system, namely by modifying their operating reserve methodologies. This paper intends to show an in-depth analysis on different operating reserve methodologies and investigate their impacts on power system reliability and economic efficiency.« less

Simple Sensitivity Analysis for Orion Guidance Navigation and Control

NASA Technical Reports Server (NTRS)

Pressburger, Tom; Hoelscher, Brian; Martin, Rodney; Sricharan, Kumar

2013-01-01

The performance of Orion flight software, especially its GNC software, is being analyzed by running Monte Carlo simulations of Orion spacecraft flights. The simulated performance is analyzed for conformance with flight requirements, expressed as performance constraints. Flight requirements include guidance (e.g. touchdown distance from target) and control (e.g., control saturation) as well as performance (e.g., heat load constraints). The Monte Carlo simulations disperse hundreds of simulation input variables, for everything from mass properties to date of launch. We describe in this paper a sensitivity analysis tool ("Critical Factors Tool" or CFT) developed to find the input variables or pairs of variables which by themselves significantly influence satisfaction of requirements or significantly affect key performance metrics (e.g., touchdown distance from target). Knowing these factors can inform robustness analysis, can inform where engineering resources are most needed, and could even affect operations. The contributions of this paper include the introduction of novel sensitivity measures, such as estimating success probability, and a technique for determining whether pairs of factors are interacting dependently or independently. The tool found that input variables such as moments, mass, thrust dispersions, and date of launch were found to be significant factors for success of various requirements. Examples are shown in this paper as well as a summary and physics discussion of EFT-1 driving factors that the tool found.

[Inter-and intra-operator variability in the analysis of semen parameters: results from a quality control program].

PubMed

Daoud, Salima; Chakroun-Feki, Nozha; Sellami, Afifa; Ammar-Keskes, Leila; Rebai, Tarek

2016-01-01

Semen analysis is a key part of male infertility investigation. The necessity of quality management implementation in the andrology laboratory has been recognized in order to ensure the reliability of its results. The aim of this study was to evaluate intra- and inter-individual variability in the assessment of semen parameters in our laboratory through a quality control programme. Four participants from the laboratory with different experience levels have participated in this study. Semen samples of varying quality were assessed for sperm motility, concentration and morphology and the results were used to evaluate inter-participant variability. In addition, replicates of each semen sample were analyzed to determine intra-individual variability for semen parameters analysis. The average values of inter-participant coefficients of variation for sperm motility, concentration and morphology were 12.8%, 19.8% and 48.9% respectively. The mean intra-participant coefficients of variation were, respectively, 6.9%, 12.3% and 42.7% for sperm motility, concentration and morphology. Despite some random errors of under- or overestimation, the overall results remained within the limits of acceptability for all participants. Sperm morphology assessment was particularly influenced by the participant's level of experience. The present data emphasize the need for appropriate training of the laboratory staff and for regular participation in internal quality control programmes in order to improve the reliability of laboratory results.

Satellite-based Analysis of CO Variability over the Amazon Basin

NASA Astrophysics Data System (ADS)

Deeter, M. N.; Emmons, L. K.; Martinez-Alonso, S.; Tilmes, S.; Wiedinmyer, C.

2017-12-01

Pyrogenic emissions from the Amazon Basin exert significant influence on both climate and air quality but are highly variable from year to year. The ability of models to simulate the impact of biomass burning emissions on downstream atmospheric concentrations depends on (1) the quality of surface flux estimates (i.e., emissions inventories), (2) model dynamics (e.g., horizontal winds, large-scale convection and mixing) and (3) the representation of atmospheric chemical processes. With an atmospheric lifetime of a few months, carbon monoxide (CO) is a commonly used diagnostic for biomass burning. CO products are available from several satellite instruments and allow analyses of CO variability over extended regions such as the Amazon Basin with useful spatial and temporal sampling characteristics. The MOPITT ('Measurements of Pollution in the Troposphere') instrument was launched on the NASA Terra platform near the end of 1999 and is still operational. MOPITT is uniquely capable of measuring tropospheric CO concentrations using both thermal-infrared and near-infrared observations, resulting in the ability to independently retrieve lower- and upper-troposphere CO concentrations. We exploit the 18-year MOPITT record and related datasets to analyze the variability of CO over the Amazon Basin and evaluate simulations performed with the CAM-chem chemical transport model. We demonstrate that observed differences between MOPITT observations and model simulations provide important clues regarding emissions inventories, convective mixing and long-range transport.

Enhanced Biennial Variability in the Pacific due to Atlantic Capacitor Effect after the Early 1990s

NASA Astrophysics Data System (ADS)

WANG, L.; Yu, J. Y.; Paek, H.

2016-12-01

The El Niño-Southern Oscillation (ENSO) and Pacific subtropical highs (PSHs) have major impacts on social and ecological systems through their influences on severe natural hazards including tropical storms, coastal erosions, droughts and floods. The ability to forecast ENSO and PSHs requires an understanding of the underlying physical mechanisms that drive their variability. Here we present an Atlantic capacitor effect mechanism to suggest the Atlantic as a key pacemaker of the biennial variability in the Pacific including ENSO and PSHs in recent decades, while the pacemaker was previously considered to be mainly lied within the Pacific or Indian Oceans. The "charging" (i.e., ENSO imprinting the North Tropical Atlantic (NTA) sea surface temperature (SST) via an atmospheric bridge mechanism) and "discharging" (i.e., the NTA SST triggering the following ENSO via a subtropical teleconnection mechanism) process works alternately, generating the biennial rhythmic changes in the Pacific. After the early-1990s, the positive phase of the Atlantic Multidecadal Oscillation and global warming provides more favorable background states over the NTA that enable the Atlantic capacitor effect to operate more efficiently, giving rise to enhanced biennial variability in the Pacific which may increase the occurrence frequency of severe natural hazard events. The results highlight the increasing important role of the Atlantic-Pacific coupling as an important pacemaker of the ENSO cycle in recent decades.

A sorting system with automated gates permits individual operant experiments with mice from a social home cage.

PubMed

Winter, York; Schaefers, Andrea T U

2011-03-30

Behavioral experiments based on operant procedures can be time-consuming for small amounts of data. While individual testing and handling of animals can influence attention, emotion, and behavior, and interfere with experimental outcome, many operant protocols require individual testing. We developed an RFID-technology- and transponder-based sorting system that allows removing the human factor for longer-term experiments. Identity detectors and automated gates route mice individually from their social home cage to an adjacent operant compartment with 24/7 operation. CD1-mice learnt quickly to individually pass through the sorting system. At no time did more than a single mouse enter the operant compartment. After 3 days of adjusting to the sorting system, groups of 4 mice completed about 50 experimental trials per day in the operant compartment without experimenter intervention. The automated sorting system eliminates handling, isolation, and disturbance of the animals, eliminates experimenter-induced variability, saves experimenter time, and is financially economical. It makes possible a new approach for high-throughput experimentation, and is a viable tool for increasing quality and efficiency of many behavioral and neurobiological investigations. It can connect a social home cage, through individual sorting automation, to diverse setups including classical operant chambers, mazes, or arenas with video-based behavior classification. Such highly automated systems will permit efficient high-throughput screening even for transgenic animals with only subtle neurological or psychiatric symptoms where elaborate or longer-term protocols are required for behavioral diagnosis. Copyright © 2011 Elsevier B.V. All rights reserved.

The impact of monsoon intraseasonal variability on renewable power generation in India

NASA Astrophysics Data System (ADS)

Dunning, C. M.; Turner, A. G.; Brayshaw, D. J.

2015-06-01

India is increasingly investing in renewable technology to meet rising energy demands, with hydropower and other renewables comprising one-third of current installed capacity. Installed wind-power is projected to increase 5-fold by 2035 (to nearly 100GW) under the International Energy Agency's New Policies scenario. However, renewable electricity generation is dependent upon the prevailing meteorology, which is strongly influenced by monsoon variability. Prosperity and widespread electrification are increasing the demand for air conditioning, especially during the warm summer. This study uses multi-decadal observations and meteorological reanalysis data to assess the impact of intraseasonal monsoon variability on the balance of electricity supply from wind-power and temperature-related demand in India. Active monsoon phases are characterized by vigorous convection and heavy rainfall over central India. This results in lower temperatures giving lower cooling energy demand, while strong westerly winds yield high wind-power output. In contrast, monsoon breaks are characterized by suppressed precipitation, with higher temperatures and hence greater demand for cooling, and lower wind-power output across much of India. The opposing relationship between wind-power supply and cooling demand during active phases (low demand, high supply) and breaks (high demand, low supply) suggests that monsoon variability will tend to exacerbate fluctuations in the so-called demand-net-wind (i.e., electrical demand that must be supplied from non-wind sources). This study may have important implications for the design of power systems and for investment decisions in conventional schedulable generation facilities (such as coal and gas) that are used to maintain the supply/demand balance. In particular, if it is assumed (as is common) that the generated wind-power operates as a price-taker (i.e., wind farm operators always wish to sell their power, irrespective of price) then investors in conventional facilities will face additional weather-volatility through the monsoonal impact on the length and frequency of production periods (i.e. their load-duration curves).

Assimilation of Dual-Polarimetric Radar Observations with WRF GSI

NASA Technical Reports Server (NTRS)

Li, Xuanli; Mecikalski, John; Fehnel, Traci; Zavodsky, Bradley; Srikishen, Jayanthi

2014-01-01

Dual-polarimetric (dual-pol) radar typically transmits both horizontally and vertically polarized radio wave pulses. From the two different reflected power returns, more accurate estimate of liquid and solid cloud and precipitation can be provided. The upgrade of the traditional NWS WSR-88D radar to include dual-pol capabilities will soon be completed for the entire NEXRAD network. Therefore, the use of dual-pol radar network will have a broad impact in both research and operational communities. The assimilation of dual-pol radar data is especially challenging as few guidelines have been provided by previous research. It is our goal to examine how to best use dual-pol radar data to improve forecast of severe storm and forecast initialization. In recent years, the Development Testbed Center (DTC) has released the community Gridpoint Statistical Interpolation (GSI) DA system for the Weather Research and Forecasting (WRF) model. The community GSI system runs in independently environment, yet works functionally equivalent to operational centers. With collaboration with the NASA Short-term Prediction Research and Transition (SPoRT) Center, this study explores regional assimilation of the dual-pol radar variables from the WSR-88D radars for real case storms. Our presentation will highlight our recent effort on incorporating the horizontal reflectivity (ZH), differential reflectivity (ZDR), specific differential phase (KDP), and radial velocity (VR) data for initializing convective storms, with a significant focus being on an improved representation of hydrometeor fields. In addition, discussion will be provided on the development of enhanced assimilation procedures in the GSI system with respect to dual-pol variables. Beyond the dual-pol variable assimilation procedure developing within a GSI framework, highresolution (=1 km) WRF model simulations and storm scale data assimilation experiments will be examined, emphasizing both model initialization and short-term forecast of precipitation fields and processes. Further details of the methodology of data assimilation, the impact of different dual-pol variables, the influence on precipitation forecast will be presented at the conference.

Directional semivariogram analysis to identify and rank controls on the spatial variability of fracture networks

NASA Astrophysics Data System (ADS)

Hanke, John R.; Fischer, Mark P.; Pollyea, Ryan M.

2018-03-01

In this study, the directional semivariogram is deployed to investigate the spatial variability of map-scale fracture network attributes in the Paradox Basin, Utah. The relative variability ratio (R) is introduced as the ratio of integrated anisotropic semivariogram models, and R is shown to be an effective metric for quantifying the magnitude of spatial variability for any two azimuthal directions. R is applied to a GIS-based data set comprising roughly 1200 fractures, in an area which is bounded by a map-scale anticline and a km-scale normal fault. This analysis reveals that proximity to the fault strongly influences the magnitude of spatial variability for both fracture intensity and intersection density within 1-2 km. Additionally, there is significant anisotropy in the spatial variability, which is correlated with trends of the anticline and fault. The direction of minimum spatial correlation is normal to the fault at proximal distances, and gradually rotates and becomes subparallel to the fold axis over the same 1-2 km distance away from the fault. We interpret these changes to reflect varying scales of influence of the fault and the fold on fracture network development: the fault locally influences the magnitude and variability of fracture network attributes, whereas the fold sets the background level and structure of directional variability.

Development of manuals for the effective use of variable message signs.

DOT National Transportation Integrated Search

1995-01-01

A comprehensive research effort to develop operator's manuals for variable message signs (VMSs) was undertaken to improve the operations of both portable and permanent (fixed-site) VMSs in Virginia. This report describes the development of two manual...

Direct and indirect climate controls predict heterogeneous early-mid 21st century wildfire burned area across western and boreal North America

PubMed Central

Falk, Donald A.; Westerling, Anthony L.; Swetnam, Thomas W.

2017-01-01

Predicting wildfire under future conditions is complicated by complex interrelated drivers operating across large spatial scales. Annual area burned (AAB) is a useful index of global wildfire activity. Current and antecedent seasonal climatic conditions, and the timing of snowpack melt, have been suggested as important drivers of AAB. As climate warms, seasonal climate and snowpack co-vary in intricate ways, influencing fire at continental and sub-continental scales. We used independent records of seasonal climate and snow cover duration (last date of permanent snowpack, LDPS) and cell-based Structural Equation Models (SEM) to separate direct (climatic) and indirect (snow cover) effects on relative changes in AAB under future climatic scenarios across western and boreal North America. To isolate seasonal climate variables with the greatest effect on AAB, we ran multiple regression models of log-transformed AAB on seasonal climate variables and LDPS. We used the results of multiple regressions to project future AAB using GCM ensemble climate variables and LDPS, and validated model predictions with recent AAB trends. Direct influences of spring and winter temperatures on AAB are larger and more widespread than the indirect effect mediated by changes in LDPS in most areas. Despite significant warming trends and reductions in snow cover duration, projected responses of AAB to early-mid 21st century are heterogeneous across the continent. Changes in AAB range from strongly increasing (one order of magnitude increases in AAB) to moderately decreasing (more than halving of baseline AAB). Annual wildfire area burned in coming decades is likely to be highly geographically heterogeneous, reflecting interacting regional and seasonal climate drivers of fire occurrence and spread. PMID:29244839

Optimization study for Pb(II) and COD sequestration by consortium of sulphate-reducing bacteria

NASA Astrophysics Data System (ADS)

Verma, Anamika; Bishnoi, Narsi R.; Gupta, Asha

2017-09-01

In this study, initial minimum inhibitory concentration (MIC) of Pb(II) ions was analysed to check optimum concentration of Pb(II) ions at which the growth of sulphate-reducing consortium (SRC) was found to be maximum. 80 ppm of Pb(II) ions was investigated as minimum inhibitory concentration for SRC. Influence of electron donors such as lactose, sucrose, glucose and sodium lactate was examined to investigate best carbon source for growth and activity of sulphate-reducing bacteria. Sodium lactate was found to be the prime carbon source for SRC. Later optimization of various parameters was executed using Box-Behnken design model of response surface methodology to explore the effectiveness of three independent operating variables, namely, pH (5.0-9.0), temperature (32-42 °C) and time (5.0-9.0 days), on dependent variables, i.e. protein content, precipitation of Pb(II) ions, and removal of COD by SRC biomass. Maximum removal of COD and Pb(II) was observed to be 91 and 98 %, respectively, at pH 7.0 and temperature 37 °C and incubation time 7 days. According to response surface analysis and analysis of variance, the experimental data were perfectly fitted to the quadratic model, and the interactive influence of pH, temperature and time on Pb(II) and COD removal was highly significant. A high regression coefficient between the variables and response ( r 2 = 0.9974) corroborate eminent evaluation of experimental data by second-order polynomial regression model. SEM and Fourier transform infrared analysis was performed to investigate morphology of PbS precipitates, sorption mechanism and involved functional groups in metal-free and metal-loaded biomass of SRC for Pb(II) binding.

Global Specification of the Post-Sunset Equatorial Ionization Anomaly

NASA Astrophysics Data System (ADS)

Coker, C.; Dandenault, P. B.; Dymond, K.; Budzien, S. A.; Nicholas, A. C.; Chua, D. H.; McDonald, S. E.; Metzler, C. A.; Walker, P. W.; Scherliess, L.; Schunk, R. W.; Gardner, L. C.; Zhu, L.

2012-12-01

The Special Sensor Ultraviolet Limb Imager (SSULI) on the Defense Meteorological Satellite Program (DMSP) is used to specify the post-sunset Equatorial Ionization Anomaly. Ultraviolet emission profiles of 135.6 nm and 91.1 nm emissions from O++ e recombination are measured in successive altitude scans along the orbit of the satellite. The overlapping sample geometry provides for a high resolution reconstruction of the ionosphere in altitude and latitude for each pass of the satellite. Emission profiles are ingested by the Global Assimilation of Ionospheric Measurements (GAIM) space weather model, which was developed by Utah State University and is run operationally at the Air Force Weather Agency (AFWA). The resulting specification of the equatorial ionosphere reveals significant variability in the postsunset anomaly, which is reflective of the driving space weather processes, namely, electric fields and neutral winds. Significant longitudinal and day-to-day variability in the magnitude (or even existence) of the post-sunset anomaly reveal the influence of atmospheric tides and waves as well as geomagnetic disturbances on the pre-reversal enhancement of the electric field. Significant asymmetry between anomaly crests reveals the influence of atmospheric tides and waves on meridional neutral winds. A neutral wind parallel to the magnetic field line pushes plasma up (or down) the field lines, which raises (or lowers) the altitude of the crests and modifies the horizontal location and magnitude of the crests. The variability in the post-sunset anomaly is one of the largest sources of error in ionospheric specification models. The SSULI instrument provides critical data towards the reduction of this specification error and the determination of key driver parameters used in ionospheric forecasting. Acknowledgements: This research was supported by the USAF Space and Missile Systems Center (SMC), the Naval Research Laboratory (NRL) Base Program, and the Office of Naval Research (ONR).

Spatio-Temporal Interdependence of Bacteria and Phytoplankton during a Baltic Sea Spring Bloom

PubMed Central

Bunse, Carina; Bertos-Fortis, Mireia; Sassenhagen, Ingrid; Sildever, Sirje; Sjöqvist, Conny; Godhe, Anna; Gross, Susanna; Kremp, Anke; Lips, Inga; Lundholm, Nina; Rengefors, Karin; Sefbom, Josefin; Pinhassi, Jarone; Legrand, Catherine

2016-01-01

In temperate systems, phytoplankton spring blooms deplete inorganic nutrients and are major sources of organic matter for the microbial loop. In response to phytoplankton exudates and environmental factors, heterotrophic microbial communities are highly dynamic and change their abundance and composition both on spatial and temporal scales. Yet, most of our understanding about these processes comes from laboratory model organism studies, mesocosm experiments or single temporal transects. Spatial-temporal studies examining interactions of phytoplankton blooms and bacterioplankton community composition and function, though being highly informative, are scarce. In this study, pelagic microbial community dynamics (bacteria and phytoplankton) and environmental variables were monitored during a spring bloom across the Baltic Proper (two cruises between North Germany to Gulf of Finland). To test to what extent bacterioplankton community composition relates to the spring bloom, we used next generation amplicon sequencing of the 16S rRNA gene, phytoplankton diversity analysis based on microscopy counts and population genotyping of the dominating diatom Skeletonema marinoi. Several phytoplankton bloom related and environmental variables were identified to influence bacterial community composition. Members of Bacteroidetes and Alphaproteobacteria dominated the bacterial community composition but the bacterial groups showed no apparent correlation with direct bloom related variables. The less abundant bacterial phyla Actinobacteria, Planctomycetes, and Verrucomicrobia, on the other hand, were strongly associated with phytoplankton biomass, diatom:dinoflagellate ratio, and colored dissolved organic matter (cDOM). Many bacterial operational taxonomic units (OTUs) showed high niche specificities. For example, particular Bacteroidetes OTUs were associated with two distinct genetic clusters of S. marinoi. Our study revealed the complexity of interactions of bacterial taxa with inter- and intraspecific genetic variation in phytoplankton. Overall, our findings imply that biotic and abiotic factors during spring bloom influence bacterial community dynamics in a hierarchical manner. PMID:27148206

Direct and indirect climate controls predict heterogeneous early-mid 21st century wildfire burned area across western and boreal North America.

PubMed

Kitzberger, Thomas; Falk, Donald A; Westerling, Anthony L; Swetnam, Thomas W

2017-01-01

Predicting wildfire under future conditions is complicated by complex interrelated drivers operating across large spatial scales. Annual area burned (AAB) is a useful index of global wildfire activity. Current and antecedent seasonal climatic conditions, and the timing of snowpack melt, have been suggested as important drivers of AAB. As climate warms, seasonal climate and snowpack co-vary in intricate ways, influencing fire at continental and sub-continental scales. We used independent records of seasonal climate and snow cover duration (last date of permanent snowpack, LDPS) and cell-based Structural Equation Models (SEM) to separate direct (climatic) and indirect (snow cover) effects on relative changes in AAB under future climatic scenarios across western and boreal North America. To isolate seasonal climate variables with the greatest effect on AAB, we ran multiple regression models of log-transformed AAB on seasonal climate variables and LDPS. We used the results of multiple regressions to project future AAB using GCM ensemble climate variables and LDPS, and validated model predictions with recent AAB trends. Direct influences of spring and winter temperatures on AAB are larger and more widespread than the indirect effect mediated by changes in LDPS in most areas. Despite significant warming trends and reductions in snow cover duration, projected responses of AAB to early-mid 21st century are heterogeneous across the continent. Changes in AAB range from strongly increasing (one order of magnitude increases in AAB) to moderately decreasing (more than halving of baseline AAB). Annual wildfire area burned in coming decades is likely to be highly geographically heterogeneous, reflecting interacting regional and seasonal climate drivers of fire occurrence and spread.

Fixed-speed and Variable-speed Pumped Storage Dispatch Model in Power Systems with High Renewable Penetration

NASA Astrophysics Data System (ADS)

Yuan, Bo; Zong, Jin; Xu, Zhicheng

2018-06-01

According to different operating characteristics of pumped storage fixed speed unit and variable speed unit, a joint dispatching model of pumped storage unit and other types of units based on mixed integer linear optimization is constructed. The model takes into account the operating conditions, reservoir capacity, cycle type and other pumped storage unit constraints, but also consider the frequent start and stop and the stability of the operation of the unit caused by the loss. Using the Cplex solver to solve the model, the empirical example of the provincial power grid shows that the model can effectively arrange the pumping storage speed and the dispatching operation of the variable speed unit under the precondition of economic life of the unit, and give full play to the function of peak shaving and accommodating new energy. Because of its more flexible regulation characteristics of power generation and pumping conditions, the variable speed unit can better improve the operating conditions of other units in the system and promote the new energy dissipation.

Professional satisfaction of women in surgery: results of a national study.

PubMed

End, Adelheid; Mittlboeck, Martina; Piza-Katzer, Hildegunde

2004-11-01

Individual, group, and organizational factors influence the professional satisfaction of women surgeons in Austria. Survey on professional and private issues sent out by mail in 2000 and 2001. Women surgeons working in hospitals and/or in private practices and those who were retired or on maternity leave. All 351 Austrian women surgeons of all core surgical specialties (general, trauma, pediatric, plastic, thoracic, and cardiovascular), certified or in training, were addressed. Proportional odds regression models were used to correlate professional satisfaction with objectively measurable prognostic factors such as age, surgical subspecialty, status of training, type of hospital, location of work (federal states vs the capital), status of activity (active vs on maternity leave), profession of private partner, number of children, and subjectively assessed prognostic factors such as operative volume and departmental organization. The response rate was 58.7% (206/351). One hundred eighty-seven surgeons-active or on maternity leave-were included in the analysis. Higher satisfaction was reported by active surgeons in subspecialties, certified surgeons, comparatively younger and older surgeons, surgeons working in hospitals outside the capital, and surgeons with a physician as a partner. When entering subjectively assessed variables into the model, the quality of departmental organization and operative volume (P<.001), as well as the status of activity (P<.001), had the strongest effect. Women surgeons' professional satisfaction highly depends on departmental organization and status of activity. Inadequate leadership, low operative volume, and being on maternity leave have a negative effect on job satisfaction. Private factors seem to be of little influence. Optimal departmental organization would help women to reconcile their professional and their private lives.

Centrarchid assemblages in Mississippi state-operated fishing lakes

USGS Publications Warehouse

Olive, J.A.; Miranda, L.E.; Hubbard, W.D.

2005-01-01

We evaluated electrofishing catch per effort in 27 state-operated fishing lakes in Mississippi to identify patterns of centrarchid community composition and to determine whether those patterns were related to selected environmental characteristics and to artificial nutrient enrichment. Ordination with detrended correspondence analysis recognized two major axes accounting for 77% of the variability in species ordination. Axis 1 showed a distinct separation between the body sizes of various species. A notable exception was the density of small (<30 cm) largemouth bass Micropterus salmoides, which aligned with the large individuals of other centrarchid species. This pattern suggested that through predation, high densities of small largemouth bass exerted significant control over the size structure of fish communities. Axis 2 separated species of crappies Pomoxis spp., suggesting that conditions other than strong species interactions also moderated the composition of crappies in the assemblages. However, neither lake morphometry nor watershed composition exhibited a major influence over axes 1 or 2. In small, intensively managed lakes with low habitat complexity, the regulatory importance of biotic interactions may overwhelm that of abiotic factors. Nutrient enrichment influenced community structure by changing the densities of bluegill Lepomis macrochirus and largemouth bass substantially but had a minor or no effect on other species. The management techniques used in these state-operated lakes are usually targeted toward a particular species without adequately considering the other species within the community. Our results show that attention to community-level interactions could provide valuable insight into factors that affect the quality of the fishery, insight that is not available through traditional population-level assessments. ?? Copyright by the American Fisheries Society 2005.

Affective Behavior in Children's Athletics.

ERIC Educational Resources Information Center

Thomas, Jerry R.; Halliwell, Wayne

There may be many social psychological variables that influence or are influenced by children's behavior in organized sports. The major variable discussed in this paper is the child's motivation to participate. One cognitive theory--the attribution theory-- offers insights into the child's view of his motivation, and the effects upon this…

Culture-Specific Variables That May Affect Employment Outcomes for Mexican-American Youth with Disabilities.

ERIC Educational Resources Information Center

Meier-Kronick, Nancy

This paper reviews variables specific to the Mexican-American culture that might influence work-related behavior and outcomes for youths with disabilities from this population. Areas covered include: parental/family network; cultural view of disability; religious influences; acculturation levels; language issues; education and employment…

Influence of School-Level Variables on Aggression and Associated Attitudes of Middle School Students

ERIC Educational Resources Information Center

Henry, David B.; Farrell, Albert D.; Schoeny, Michael E.; Tolan, Patrick H.; Dymnicki, Allison B.

2011-01-01

This study sought to understand school-level influences on aggressive behavior and related social cognitive variables. Participants were 5106 middle school students participating in a violence prevention project. Predictors were school-level norms opposing aggression and favoring nonviolence, interpersonal climate (positive student-teacher…

Effects of watershed land use and geomorphology on stream low flows during severe drought conditions in the southern Blue Ridge Mountains, Georgia and North Carolina, United States

Treesearch

Katie Price; C. Jackson; Albert Parker; Trond Reitan; John Dowd; Mike Cyterski

2011-01-01

Land use and physiographic variability influence stream low flows, yet their interactions and relative influence remain unresolved. Our objective was to assess the influence of land use and watershed geomorphic characteristics on low-flow variability in the southern Blue Ridge Mountains of North Carolina and Georgia. Ten minute interval discharge data for 35 streams (...

Multiple Ion Binding Equilibria, Reaction Kinetics, and Thermodynamics in Dynamic Models of Biochemical Pathways

PubMed Central

Vinnakota, Kalyan C.; Wu, Fan; Kushmerick, Martin J.; Beard, Daniel A.

2009-01-01

The operation of biochemical systems in vivo and in vitro is strongly influenced by complex interactions between biochemical reactants and ions such as H+, Mg2+, K+, and Ca2+. These are important second messengers in metabolic and signaling pathways that directly influence the kinetics and thermodynamics of biochemical systems. Herein we describe the biophysical theory and computational methods to account for multiple ion binding to biochemical reactants and demonstrate the crucial effects of ion binding on biochemical reaction kinetics and thermodynamics. In simulations of realistic systems, the concentrations of these ions change with time due to dynamic buffering and competitive binding. In turn, the effective thermodynamic properties vary as functions of cation concentrations and important environmental variables such as temperature and overall ionic strength. Physically realistic simulations of biochemical systems require incorporating all of these phenomena into a coherent mathematical description. Several applications to physiological systems are demonstrated based on this coherent simulation framework. PMID:19216922

Workstation design in carpet hand-weaving operation: guidelines for prevention of musculoskeletal disorders.

PubMed

Choobineh, Alireza; Lahmi, Mohammadali; Hosseini, Mostafa; Shahnavaz, Houshang; Jazani, Reza Khani

2004-01-01

Carpet weavers suffer from musculoskeletal problems mainly attributed to poor working postures. Their posture is mostly constrained by the design of workstations. This study was conducted to investigate the effects of 2 design parameters (weaving height and seat type) on postural variables and subjective experience, and to develop guidelines for workstation adjustments. At an experimental workstation, 30 professional weavers worked in 9 different conditions. Working posture and weavers' perceptions were measured. It was shown that head, neck and shoulder postures were influenced by weaving height. Both design parameters influenced trunk and elbows postures. The determinant factor for weavers' perception on the neck, shoulders and elbows was found to be weaving height, and on the back and knees it was seat type. Based on the results, the following guidelines were developed: (a) weaving height should be adjusted to 20 cm above elbow height; (b) a 10 degrees forward-sloping high seat is to be used at weaving workstations.

Crowding, sex ratio and horn evolution in a South African beetle community.

PubMed

Pomfret, Joanne C; Knell, Robert J

2008-02-07

Sexually selected ornaments and weapons are exceptionally variable, even between closely related species. It has long been recognized that some of this diversity can be explained by differences in mating systems between species, but there remains substantial variation between species with similar mating systems. We investigated the roles of sex ratio (measured as operational sex ratio, OSR) and population density (measured as mean male crowding, a measure indicating the average number of conspecific males that an individual male animal will encounter) in determining horn presence in a community of South African dung beetles. Analysis of data from 14 species using a generalized least-squares model incorporating phylogenetic influences found that both OSR and mean crowding were significant predictors of horn presence, with hornless species tending to show female-biased sex ratios and high levels of crowding. The influence of mean crowding on horn diversity between species probably reflects the difficulty of guarding and monopolizing females when many competitors are present, meaning that males who adopt 'scramble' tactics tend to be favoured.

Mathematical modeling of control subsystems for CELSS: Application to diet

NASA Technical Reports Server (NTRS)

Waleh, Ahmad; Nguyen, Thoi K.; Kanevsky, Valery

1991-01-01

The dynamic control of a Closed Ecological Life Support System (CELSS) in a closed space habitat is of critical importance. The development of a practical method of control is also a necessary step for the selection and design of realistic subsystems and processors for a CELSS. Diet is one of the dynamic factors that strongly influences, and is influenced, by the operational states of all major CELSS subsystems. The problems of design and maintenance of a stable diet must be obtained from well characterized expert subsystems. The general description of a mathematical model that forms the basis of an expert control program for a CELSS is described. The formulation is expressed in terms of a complete set of time dependent canonical variables. System representation is dynamic and includes time dependent storage buffers. The details of the algorithm are described. The steady state results of the application of the method for representative diets made from wheat, potato, and soybean are presented.

Rural neighborhoods and child aggression.

PubMed

Bowen, Natasha K; Wretman, Christopher J

2014-12-01

Structural equation modeling with latent variables was used to evaluate the direct and mediated effects of a neighborhood risk factor (negative teen behaviors) on the parent-report aggressive behavior of 213 students in grades 3 through 5 attending a school in a low-income, rural community. Contagion and social control hypotheses were examined as well as hypotheses about whether the neighborhood served as a microsystem or exosystem for rural pre-adolescents. Analyses took into account the clustering of students and ordinal nature of the data. Findings suggest that rural neighborhoods may operate as both a microsystem and exosystem for children, with direct contagion effects on their aggressive behaviors as well as indirect social control effects through parenting practices. Direct effects on aggression were also found for parenting practices and child reports of friends' negative behaviors. Pre-adolescence may be a transitional stage, when influences of the neighborhood on child behavior begin to compete with influences of caregivers. Findings can inform the timing and targets of violence prevention in rural communities.

CTBT infrasound network performance to detect the 2013 Russian fireball event

DOE PAGES

Pilger, Christoph; Ceranna, Lars; Ross, J. Ole; ...

2015-03-18

The explosive fragmentation of the 2013 Chelyabinsk meteorite generated a large airburst with an equivalent yield of 500 kT TNT. It is the most energetic event recorded by the infrasound component of the Comprehensive Nuclear-Test-Ban Treaty-International Monitoring System (CTBT-IMS), globally detected by 20 out of 42 operational stations. This study performs a station-by-station estimation of the IMS detection capability to explain infrasound detections and nondetections from short to long distances, using the Chelyabinsk meteorite as global reference event. Investigated parameters influencing the detection capability are the directivity of the line source signal, the ducting of acoustic energy, and the individualmore » noise conditions at each station. Findings include a clear detection preference for stations perpendicular to the meteorite trajectory, even over large distances. Only a weak influence of stratospheric ducting is observed for this low-frequency case. As a result, a strong dependence on the diurnal variability of background noise levels at each station is observed, favoring nocturnal detections.« less

Loss of control over eating in pre-adolescent youth: the role of attachment and self-esteem.

PubMed

Goossens, Lien; Braet, Caroline; Bosmans, Guy; Decaluwé, Veerle

2011-12-01

The present study aimed to add to the limited literature on the role of self-esteem and attachment for the explanation of loss of control over eating (LC) among pre-adolescent boys and girls. Self-report questionnaires were administered to a community sample of 555 children (8-11 years; 47% female). Children reporting LC (17.6% of the sample) were characterized by a lower self-esteem and less secure attachment toward both of their parents. No gender differences emerged. Moreover, the relation between self-esteem and LC was fully mediated by attachment toward mother and partially mediated by attachment toward father. The present study provides preliminary evidence for the idea that the influence of self-esteem on LC seems to operate through a third variable that is an insecure relationship with the parents. Longitudinal research is needed to further elucidate the influence of interpersonal factors on the development of LC. Copyright © 2011 Elsevier Ltd. All rights reserved.

Analysis of Oceans' Influence on Spring Time Rainfall Variability Over Southeastern South America during the 20th Century

NASA Astrophysics Data System (ADS)

Martín, Verónica; Barreiro, Marcelo

2015-04-01

Southeastern South America (SESA) rainfall presents large variability from interannual to multidecadal times scales and is influenced by the tropical Pacific, Atlantic and Indian oceans. At the same time, these tropical oceans interact with each other inducing sea surface temperature anomalies in remote basins through atmospheric and oceanic teleconnections. In this study we employ a tool from complex networks to analyze the collective influence of the three tropical oceans on austral spring rainfall variability over SESA during the 20th century. To do so we construct a climate network considering as nodes the observed Niño3.4, Tropical North Atlantic (TNA), and Indian Ocean Dipole (IOD) indices, together with an observed or simulated precipitation (PCP) index over SESA. The mean network distance is considered as a measure of synchronization among all these phenomena during the 20th century. The approach allowed to uncover large interannual and interdecadal variability in the interaction among nodes. In particular, there are two main synchronization periods characterized by different interactions among the oceanic and precipitation nodes. Whereas in the '30s El Niño and the TNA were the main tropical oceanic phenomena that influenced SESA precipitation variability, during the '70s they were El Niño and the IOD. Simulations with an Atmospheric General Circulation Model reproduced the overall behavior of the collective influence of the tropical oceans on rainfall over SESA, and allowed to study the circulation anomalies that characterized the synchronization periods. In agreement with previous studies, the influence of El Niño on SESA precipitation variability might be understood through an increase of the northerly transport of moisture in lower levels and advection of cyclonic vorticity in upper levels. On the other hand, the interaction between the IOD and PCP can be interpreted in two possible ways. One possibility is that both nodes (IOD and PCP) are forced by El Niño. Another possibility is that the Indian Ocean warming influences rainfall over Southeastern South America through the eastward propagation of Rossby waves as suggested previously. Finally, the influence of TNA on SESA precipitation persists even when El Niño signal is removed, suggesting that SST anomalies in the tropical north Atlantic can directly influence SESA precipitation and further studies are needed to elucidate this connection. KEY WORDS: climate networks, synchronization events, climate variability, tropical ocean teleconnections, tropic-extratropic teleconnections, precipitation over SESA.

Somatotype in high performance female netball players may influence player position and the incidence of lower limb and back injuries

PubMed Central

Hopper, Diana M

1997-01-01

Aims To investigate the relation between somatotype, performance characteristics, and the incidence of injury during the Australian Netball Championships. Method Two hundred and forty high performance netball players competed at the Australian Netball Championships in which 213 (89%) were measured using the Heath-Carter somatotype scale. During these championships, in conjunction with the injury assessments, data analysis included a three factor analysis of variance (level of competition, playing position, and injury) for the dependent somatoype variables (endomorphy, mesomorphy, and ectopmorphy), and the level of significance was set at 0.05. Results For the three dependent somatotype variables, there were no main effects between endomorphy, mesomorphy, and ectopmorphy and the incidence of injury. However, for the mesomorphy and ectomorphy variables, significant main effects for the playing position were found. No main effects existed between the somatotype variables and levels of competition. Conclusion The somatotype variables did not influence the incidence of injury, but mesomorphy and ectopmorphy did influence the different playing positions. PMID:9298552

Causes of accidents in terrain parks: an exploratory factor analysis of recreational freestylers' views.

PubMed

Carús, Luis

2014-03-01

This study examines ski and snowboard terrain park users' views on aspects associated with accidents by identifying and assessing variables that may influence the occurrence of accidents and the resulting injuries. The research was conducted in a major resort in the Spanish Pyrenees, using information gathered from freestyle skiers and snowboarders aged 6 or older. To identify interrelationships among variables and to group the variables belonging to unified concepts, an exploratory factor analysis was performed using varimax rotation. The results revealed 5 factors that grouped the measured variables that may influence the occurrence of accidents while freestyling in terrain parks. The park features, conditions of the activity, and the user's personal conditions were found to have the most substantial influence on the freestylers' perceptions. Variables identified as components of the main factors of accident risk in terrain parks should be incorporated into resort management communication and policies. © 2013 Wilderness Medical Society Published by Wilderness Medical Society All rights reserved.

Playing up and playing down cultural identity: Introducing cultural influence and cultural variability.

PubMed

Ferguson, Gail M; Nguyen, Jacqueline; Iturbide, Maria I

2017-01-01

Cultural variability (CV) is introduced as an overlooked dimension of cultural identity development pertaining to emphasizing and de-emphasizing the influence of a single cultural identity (i.e., cultural influence [CI]) on daily interactions and behaviors. The Cultural IDentity Influence Measure (CIDIM) is introduced as a novel measure of CI and CV, and hypothesis-driven validation is conducted in two samples along with exploration of associations between CV and well-being. A multicultural sample of 242 emerging adults participated in a daily diary study (Mage = 19.95 years, SDage = 1.40) by completing up to eight daily online surveys containing the CIDIM, criterion measures (ethnic identity, other group orientation, ethnic identity salience and daily variability in salience, social desirability), and measures of personal and interpersonal well-being. A second validation sample (n = 245) completed a 1-time survey with the CIDIM and a subset of criterion measures. Results using both samples show evidence of CI and CV and demonstrate the validity, reliability, and domain-sensitivity of the CIDIM. Further, CV made unique and positive contributions to predicting interaction quality after accounting for ethnic salience and variability in ethnic salience. An analytic approach utilizing standard deviations produced near-identical results to multilevel modeling and is recommended for parsimony. Ethnic minority and majority individuals make daily adjustments to play up and play down the influence of cultural identity on their social interactions and behaviors, and these adjustments predict interpersonal well-being. Cultural influence and cultural variability contribute to our emerging understanding of cultural identity as dynamic and agentic. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Physical activity levels of older community-dwelling adults are influenced by summer weather variables.

PubMed

Brandon, Caitlin A; Gill, Dawn P; Speechley, Mark; Gilliland, Jason; Jones, Gareth R

2009-04-01

Adequate daily physical activity (PA) is important for maintaining functional capacity and independence in older adults. However, most older adults in Canada do not engage in enough PA to sustain fitness and functional independence. Environmental influences, such as warmer daytime temperatures, may influence PA participation; however, few studies have examined the effect of summertime temperatures on PA levels in older adults. This investigation measured the influence of summertime weather variables on PA in 48 community-dwelling older adults who were randomly recruited from a local seniors' community centre. Each participant wore an accelerometer for a single 7-consecutive-day period (between 30 May and 9 August 2006) during waking hours, and completed a PA logbook to remark on major daily PA events. Local weather variables were collected from a national weather service and compared with PA counts per minute. Regression analysis revealed a curvilinear relationship between log-transformed PA and mean daily temperature (r2 = 0.025; p < 0.05). Linear mixed effects models that accounted for repeated measures nested within individuals were performed for monthly periods, meteorological variables, sex, age, and estimated maximal oxygen consumption, with PA as the dependent variable. Age and Air Quality Index remained significant variables within the model. Higher fitness levels had no effect on allowing individuals to perform more vigorous PA in warmer temperatures.

Diagnostic accuracy and receiver-operating characteristics curve analysis in surgical research and decision making.

PubMed

Søreide, Kjetil; Kørner, Hartwig; Søreide, Jon Arne

2011-01-01

In surgical research, the ability to correctly classify one type of condition or specific outcome from another is of great importance for variables influencing clinical decision making. Receiver-operating characteristic (ROC) curve analysis is a useful tool in assessing the diagnostic accuracy of any variable with a continuous spectrum of results. In order to rule a disease state in or out with a given test, the test results are usually binary, with arbitrarily chosen cut-offs for defining disease versus health, or for grading of disease severity. In the postgenomic era, the translation from bench-to-bedside of biomarkers in various tissues and body fluids requires appropriate tools for analysis. In contrast to predetermining a cut-off value to define disease, the advantages of applying ROC analysis include the ability to test diagnostic accuracy across the entire range of variable scores and test outcomes. In addition, ROC analysis can easily examine visual and statistical comparisons across tests or scores. ROC is also favored because it is thought to be independent from the prevalence of the condition under investigation. ROC analysis is used in various surgical settings and across disciplines, including cancer research, biomarker assessment, imaging evaluation, and assessment of risk scores.With appropriate use, ROC curves may help identify the most appropriate cutoff value for clinical and surgical decision making and avoid confounding effects seen with subjective ratings. ROC curve results should always be put in perspective, because a good classifier does not guarantee the expected clinical outcome. In this review, we discuss the fundamental roles, suggested presentation, potential biases, and interpretation of ROC analysis in surgical research.

Bayesian belief network modelling of chlorine disinfection for human pathogenic viruses in municipal wastewater.

PubMed

Carvajal, Guido; Roser, David J; Sisson, Scott A; Keegan, Alexandra; Khan, Stuart J

2017-02-01

Chlorine disinfection of biologically treated wastewater is practiced in many locations prior to environmental discharge or beneficial reuse. The effectiveness of chlorine disinfection processes may be influenced by several factors, such as pH, temperature, ionic strength, organic carbon concentration, and suspended solids. We investigated the use of Bayesian multilayer perceptron (BMLP) models as efficient and practical tools for compiling and analysing free chlorine and monochloramine virus disinfection performance as a multivariate problem. Corresponding to their relative susceptibility, Adenovirus 2 was used to assess disinfection by monochloramine and Coxsackievirus B5 was used for free chlorine. A BMLP model was constructed to relate key disinfection conditions (CT, pH, turbidity) to observed Log Reduction Values (LRVs) for these viruses at constant temperature. The models proved to be valuable for incorporating uncertainty in the chlor(am)ination performance estimation and interpolating between operating conditions. Various types of queries could be performed with this model including the identification of target CT for a particular combination of LRV, pH and turbidity. Similarly, it was possible to derive achievable LRVs for combinations of CT, pH and turbidity. These queries yielded probability density functions for the target variable reflecting the uncertainty in the model parameters and variability of the input variables. The disinfection efficacy was greatly impacted by pH and to a lesser extent by turbidity for both types of disinfections. Non-linear relationships were observed between pH and target CT, and turbidity and target CT, with compound effects on target CT also evidenced. This work demonstrated that the use of BMLP models had considerable ability to improve the resolution and understanding of the multivariate relationships between operational parameters and disinfection outcomes for wastewater treatment. Copyright © 2016 Elsevier Ltd. All rights reserved.

Recovery process and determinants of adverse event occurrence in bronchoscopic procedures performed under general anaesthesia.

PubMed

Özden Omaygenç, Derya; Ünal, Nermin; Edipoğlu, Saadet İpek; Barca Şeker, Tuğçe; Özgül, Mehmet Akif; Turan, Demet; Özdemir, Cengiz; Karaca, İbrahim Oğuz; Çetinkaya, Erdoğan

2018-04-16

Regarding the fact that rigid bronchoscopy is generally performed under general anaesthesia and this patient subgroup is remarkably morbid, encountering procedure and/or anaesthesia related complications are highly likely. Here, we aimed to assess factors influencing recovery and detect possible determinants of adverse event occurrence during these operations performed in a tertiary referral centre. Eighty-one consecutive ASA I-IV patients were recruited for this investigation. In the operating theatre after induction of anaesthesia and advancement of the device, maintenance was provided with total intravenous anaesthesia. Neuromuscular blockage was invariably administered, and patients were ventilated manually. In addition to preoperative demographic and procedural characteristics, perioperative hemodynamic variables, recovery times and observed adverse events were noted. Basic demographic properties, ASA and Mallampati scores, and procedure specific variables as lesion localization, lesion and procedure type were comparable among groups assembled with reference to event occurrence. Patients who had experienced adverse event had higher heart rates. Recovery times were comparable between Event (-) and Event (+) groups. Relationship of recovery process were individually tested with all variables and only lesion type was detected to have an effect on respiration and extubation times. Among all parameters only procedural time seemed to be associated with adverse event occurrence (mins, 22.9 ± 11.9 vs 41.6 ± 28.8, P < .001). Recovery times related with return of spontaneous respiration were significantly lower in procedures performed for treatment of tumoral diseases in this study and procedure length was determined to be the ultimate factor which had an impact on adverse event occurrence. © 2018 John Wiley & Sons Ltd.

Statistical analysis and definition of blockages-prediction formulae for the wastewater network of Oslo by evolutionary computing.

PubMed

Ugarelli, Rita; Kristensen, Stig Morten; Røstum, Jon; Saegrov, Sveinung; Di Federico, Vittorio

2009-01-01

Oslo Vann og Avløpsetaten (Oslo VAV)-the water/wastewater utility in the Norwegian capital city of Oslo-is assessing future strategies for selection of most reliable materials for wastewater networks, taking into account not only material technical performance but also material performance, regarding operational condition of the system.The research project undertaken by SINTEF Group, the largest research organisation in Scandinavia, NTNU (Norges Teknisk-Naturvitenskapelige Universitet) and Oslo VAV adopts several approaches to understand reasons for failures that may impact flow capacity, by analysing historical data for blockages in Oslo.The aim of the study was to understand whether there is a relationship between the performance of the pipeline and a number of specific attributes such as age, material, diameter, to name a few. This paper presents the characteristics of the data set available and discusses the results obtained by performing two different approaches: a traditional statistical analysis by segregating the pipes into classes, each of which with the same explanatory variables, and a Evolutionary Polynomial Regression model (EPR), developed by Technical University of Bari and University of Exeter, to identify possible influence of pipe's attributes on the total amount of predicted blockages in a period of time.Starting from a detailed analysis of the available data for the blockage events, the most important variables are identified and a classification scheme is adopted.From the statistical analysis, it can be stated that age, size and function do seem to have a marked influence on the proneness of a pipeline to blockages, but, for the reduced sample available, it is difficult to say which variable it is more influencing. If we look at total number of blockages the oldest class seems to be the most prone to blockages, but looking at blockage rates (number of blockages per km per year), then it is the youngest class showing the highest blockage rate. EPR allowed identifying the relation between attitude to block and pipe's attributes in order to understand what affects the possibility to have a blockage in the pipe. EPR provides formulae to compute the accumulated number of blockages for a pipe class at the end of a given period of time. Those formulae do not represent simply regression models but highlight those variables which affect the physical phenomenon in question.

Design of a robust fuzzy controller for the arc stability of CO(2) welding process using the Taguchi method.

PubMed

Kim, Dongcheol; Rhee, Sehun

2002-01-01

CO(2) welding is a complex process. Weld quality is dependent on arc stability and minimizing the effects of disturbances or changes in the operating condition commonly occurring during the welding process. In order to minimize these effects, a controller can be used. In this study, a fuzzy controller was used in order to stabilize the arc during CO(2) welding. The input variable of the controller was the Mita index. This index estimates quantitatively the arc stability that is influenced by many welding process parameters. Because the welding process is complex, a mathematical model of the Mita index was difficult to derive. Therefore, the parameter settings of the fuzzy controller were determined by performing actual control experiments without using a mathematical model of the controlled process. The solution, the Taguchi method was used to determine the optimal control parameter settings of the fuzzy controller to make the control performance robust and insensitive to the changes in the operating conditions.

Structural dynamic interaction with solar tracking control for evolutionary Space Station concepts

NASA Technical Reports Server (NTRS)

Lim, Tae W.; Cooper, Paul A.; Ayers, J. Kirk

1992-01-01

The sun tracking control system design of the Solar Alpha Rotary Joint (SARJ) and the interaction of the control system with the flexible structure of Space Station Freedom (SSF) evolutionary concepts are addressed. The significant components of the space station pertaining to the SARJ control are described and the tracking control system design is presented. Finite element models representing two evolutionary concepts, enhanced operations capability (EOC) and extended operations capability (XOC), are employed to evaluate the influence of low frequency flexible structure on the control system design and performance. The design variables of the control system are synthesized using a constrained optimization technique to meet design requirements, to provide a given level of control system stability margin, and to achieve the most responsive tracking performance. The resulting SARJ control system design and performance of the EOC and XOC configurations are presented and compared to those of the SSF configuration. Performance limitations caused by the low frequency of the dominant flexible mode are discussed.

Prognostic predictors of patients with carcinoma of the gastric cardia.

PubMed

Zhang, Ming; Li, Zhigao; Ma, Yan; Zhu, Guanyu; Zhang, Hongfeng; Xue, Yingwei

2012-05-01

This study gives insight into survival predictors and clinicopathological features of carcinoma of the gastric cardia. The study included 233 patients who underwent operation for carcinoma of the gastric cardia. Clinicopathological prognostic variables were evaluated as predictors of long-term survival by univariate and multivariate analysis. Cox regression was used for multivariate analysis and survival curves were drawn by the Kaplan- Meier method. Carcinoma of the gastric cardia was characterized by positive lymph node metastasis (77.3%), serosal invasion (83.3%) and more stage III or IV tumors (72.5%). Overall 5-year survival rate was 21.9% and median survival period was 24 months. The 5-year survival rate was influenced by tumor size, depth on invasion, lymph node metastasis, extent of lymph node dissection, disease stage, operation methods and resection margin. The absent of serosal invasion and lymph node metastasis, curative resection should be considered to be the favourable predictors of long-term survival of patients with carcinoma of the gastric cardia.

Development and Implementation of Software for Visualizing and Editing Multidimensional Flight Simulation Input Data

NASA Technical Reports Server (NTRS)

Whelan, Todd Michael

1996-01-01

In a real-time or batch mode simulation that is designed to model aircraft dynamics over a wide range of flight conditions, a table look- up scheme is implemented to determine the forces and moments on the vehicle based upon the values of parameters such as angle of attack, altitude, Mach number, and control surface deflections. Simulation Aerodynamic Variable Interface (SAVI) is a graphical user interface to the flight simulation input data, designed to operate on workstations that support X Windows. The purpose of the application is to provide two and three dimensional visualization of the data, to allow an intuitive sense of the data set. SAVI also allows the user to manipulate the data, either to conduct an interactive study of the influence of changes on the vehicle dynamics, or to make revisions to data set based on new information such as flight test. This paper discusses the reasons for developing the application, provides an overview of its capabilities, and outlines the software architecture and operating environment.

A pilot study of personal exposure to respirable and inhalable dust during the sanding and sawing of medium density fibreboard (MDF) and soft wood.

PubMed

Hursthouse, Andrew; Allan, Fraser; Rowley, Louise; Smith, Frank

2004-08-01

A pilot study of production of respirable and inhalable dusts from sawing and sanding medium density fibreboard (MDF) and softwood in a typical cabinet-making workshop produced high but variable exposure levels at the bench and operator position. Exposure levels for the total inhalable fraction (approximately <100 microm) were 6.9-91 mg m(-3) for MDF and 2.5-45 mg m(-3) for softwood. For the respirable fraction (< 10 microm) levels were 0.4-13 mg m(-3) for MDF and 0.4-2.9 mg m(-3) for softwood. These results show significant dust loading is produced in the coarser fraction and that the material used has a significant impact on levels produced. It suggests that fuller evaluation of operator influence of fine dust production is needed and may question the common application of a single inhalable exposure standard for wood dust to all wood working scenarios.

Partial-coverage posterior ceramic restorations. Part 1: a return to diligence.

PubMed

Liebenberg, W H

2001-01-01

The application of multisurfaced tooth-colored restorations in the posterior dentition is an exercise in risk tolerance when dentin occupies the bulk of the tooth substrate. Not only is interfacial integrity capricious, but also a recent in vivo study has confirmed that dentin bond strengths deteriorate with time. Although the literature is replete with esthetic guidelines for posterior restitution, most practicing clinicians appreciate the prime tenet that clinical success involves more than esthetic realism in the posterior dentition. Success with indirect ceramic restorations is dependent on interfacial integrity, which, although multitudinous, is contingently related to operative competence. Innovative clinical techniques are described in this two-part article, along with a discussion of the probationary status of current adhesive options and the need for excellence in all phases of this demanding restorative sequence. Restorative success in the posterior dentition is profoundly influenced by the variability of operative competence and diligence. This article discusses the precincts of posterior indirect ceramic restorations and submits a number of innovative solutions to the clinical challenge.

Grating array systems having a plurality of gratings operative in a coherently additive mode and methods for making such grating array systems

DOEpatents

Kessler, Terrance J [Mendon, NY; Bunkenburg, Joachim [Victor, NY; Huang, Hu [Pittsford, NY

2007-02-13

A plurality of gratings (G1, G2) are arranged together with a wavefront sensor, actuators, and feedback system to align the gratings in such a manner, that they operate like a single, large, monolithic grating. Sub-wavelength-scale movements in the mechanical mounting, due to environmental influences, are monitored by an interferometer (28), and compensated by precision actuators (16, 18, 20) that maintain the coherently additive mode. The actuators define the grating plane, and are positioned in response to the wavefronts from the gratings and a reference flat, thus producing the interferogram that contains the alignment information. Movement of the actuators is also in response to a diffraction-limited spot on the CCD (36) to which light diffracted from the gratings is focused. The actuator geometry is implemented to take advantage of the compensating nature of the degrees of freedom between gratings, reducing the number of necessary control variables.

Does respiratory sinus arrhythmia occur in fishes?

PubMed Central

Campbell, Hamish A; Taylor, Edwin W; Egginton, Stuart

2005-01-01

The hypothesis that respiratory modulation of heart rate variability (HRV) or respiratory sinus arrhythmia (RSA) is restricted to mammals was tested on four Antarctic and four sub-Antarctic species of fish, that shared close genotypic or ecotypic similarities but, due to their different environmental temperatures, faced vastly different selection pressures related to oxygen supply. The intrinsic heart rate (fH) for all the fish species studied was ∼25% greater than respiration rate (fV), but vagal activity successively delayed heart beats, producing a resting fH that was synchronized with fV in a progressive manner. Power spectral statistics showed that these episodes of relative bradycardia occurred in a cyclical manner every 2–4 heart beats in temperate species but at >4 heart beats in Antarctic species, indicating a more relaxed selection pressure for cardio-respiratory coupling. This evidence that vagally mediated control of fH operates around the ventilatory cycle in fish demonstrates that influences similar to those controlling RSA in mammals operate in non-mammalian vertebrates. PMID:17148239

Spacecraft Thermal Control

NASA Technical Reports Server (NTRS)

Birur, Gajanana C.; Siebes, Georg; Swanson, Theodore D.; Powers, Edward I. (Technical Monitor)

2001-01-01

Thermal control of the spacecraft is typically achieved by removing heat from the spacecraft parts that tend to overheat and adding heat to the parts that tend get too cold. The equipment on the spacecraft can get very hot if it is exposed to the sun or have internal heat generation. The pans also can get very cold if they are exposed to the cold of deep space. The spacecraft and instruments must be designed to achieve proper thermal balance. The combination of the spacecraft's external thermal environment, its internal heat generation (i.e., waste heat from the operation of electrical equipment), and radiative heat rejection will determine this thermal balance. It should also be noted that this is seldom a static situation, external environmental influences and internal heat generation are normally dynamic variables which change with time. Topics discussed include thermal control system components, spacecraft mission categories, spacecraft thermal requirements, space thermal environments, thermal control hardware, launch and flight operations, advanced technologies for future spacecraft,

Social and Individual Influences on Tractor Operating Practices of Young Adult Agricultural Workers.

PubMed

Rudolphi, Josie M; Campo, Shelly; Gerr, Fred; Rohlman, Diane S

2018-05-01

Tractor-related incidents are the leading cause of agricultural-related fatalities in the United States. Injuries from rollovers can be prevented by equipping tractors with rollover protective structures (ROPS, an engineering approach) and by using seatbelts (a behavior-based approach). While adult farmers report low seatbelt use and frequent use of tractors without ROPS, it is unknown whether the young adult population has adopted similar tractor driving practices. This study was designed to identify tractor operating practices among young adult agricultural workers and the influence of supervisors, peers, and parents on their safety behaviors. An online survey was conducted among college students enrolled in agricultural science classes in four Midwestern colleges and universities. Participants answered questions about their tractor operating practices, the influence of supervisors, peers, parents, and individual risk taking tendencies on their workplace practices. A tractor operation safety score was estimated from participants' responses. Linear regression was used to examine the association of these influences and the tractor operation safety score. Of the 193 respondents, most (78.8%) reported that they never or rarely wear a seatbelt when operating a tractor with a ROPS. Supervisory influences, such as being negatively evaluated by a supervisor, were found to be more strongly associated with tractor operating behaviors than peer or parent influence. Young adult agricultural workers frequently reported unsafe tractor operating behaviors. Supervisors were found to have the most influence over reported behaviors of young adult agricultural workers. Copyright © 2017 The Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.