Using fire dynamics simulator to reconstruct a hydroelectric power plant fire accident.

PubMed

Chi, Jen-Hao; Wu, Sheng-Hung; Shu, Chi-Min

2011-11-01

The location of the hydroelectric power plant poses a high risk to occupants seeking to escape in a fire accident. Calculating the heat release rate of transformer oil as 11.5 MW/m(2), the fire at the Taiwan Dajia-River hydroelectric power plant was reconstructed using the fire dynamics simulator (FDS). The variations at the escape route of the fire hazard factors temperature, radiant heat, carbon monoxide, and oxygen were collected during the simulation to verify the causes of the serious casualties resulting from the fire. The simulated safe escape time when taking temperature changes into account is about 236 sec, 155 sec for radiant heat changes, 260 sec for carbon monoxide changes, and 235-248 sec for oxygen changes. These escape times are far less than the actual escape time of 302 sec. The simulation thus demonstrated the urgent need to improve escape options for people escaping a hydroelectric power plant fire. © 2011 American Academy of Forensic Sciences.

Experimental Study of Flow Through Carotid Aneurysms

NASA Astrophysics Data System (ADS)

Masoomi, Faezeh; Mejia-Alvarez, Ricardo

2017-11-01

There is evidence that traditional endovascular techniques like coiling are not effective for treatment of wide-neck cerebral aneurysms. Flow Diverter Stents (FDS) have emerged as promising devices for treating complex aneurysms since they enable treatment of aneurysms that were considered untreatable before. Recent studies suggest a number of associated risks with FDS, including in-stent thrombosis, perianeurysmal edema, delayed hemorrhage, and perforator occlusions. Chong et al. simulated hemodynamic behavior using patient-specific data. From their study, it is possible to infer that the standard deviation of energy loss could be a good predictor for intervention success. The aim of this study is to investigate the flow in models of cerebral aneurysms before and after FDS insertion using PIV. These models will be based on actual clinical studies and will be fabricated with advanced additive manufacturing techniques. These data will then be used to explore flow parameters that could inform the likelihood of post-intervention aneurysm rupture, and help determine FDS designs that better suit any particular patient before its procedure.

Hemodynamic Changes Caused by Flow Diverters in Rabbit Aneurysm Models: Comparison of Virtual and Realistic FD Deployments Based on Micro-CT Reconstruction

PubMed Central

Fang, Yibin; Yu, Ying; Cheng, Jiyong; Wang, Shengzhang; Wang, Kuizhong; Liu, Jian-Min; Huang, Qinghai

2013-01-01

Adjusting hemodynamics via flow diverter (FD) implantation is emerging as a novel method of treating cerebral aneurysms. However, most previous FD-related hemodynamic studies were based on virtual FD deployment, which may produce different hemodynamic outcomes than realistic (in vivo) FD deployment. We compared hemodynamics between virtual FD and realistic FD deployments in rabbit aneurysm models using computational fluid dynamics (CFD) simulations. FDs were implanted for aneurysms in 14 rabbits. Vascular models based on rabbit-specific angiograms were reconstructed for CFD studies. Real FD configurations were reconstructed based on micro-CT scans after sacrifice, while virtual FD configurations were constructed with SolidWorks software. Hemodynamic parameters before and after FD deployment were analyzed. According to the metal coverage (MC) of implanted FDs calculated based on micro-CT reconstruction, 14 rabbits were divided into two groups (A, MC >35%; B, MC <35%). Normalized mean wall shear stress (WSS), relative residence time (RRT), inflow velocity, and inflow volume in Group A were significantly different (P<0.05) from virtual FD deployment, but pressure was not (P>0.05). The normalized mean WSS in Group A after realistic FD implantation was significantly lower than that of Group B. All parameters in Group B exhibited no significant difference between realistic and virtual FDs. This study confirmed MC-correlated differences in hemodynamic parameters between realistic and virtual FD deployment. PMID:23823503

User's guide for the Flight Design System (FDS)

NASA Technical Reports Server (NTRS)

Ramsey, H. R.; Atwood, M. E.; Frisius, W. G.; Turner, A. A.; Willoughby, J. K.

1980-01-01

Information about the Flight Design System (FDS) in the context of flight design is presented. The guide introduces the FDS user to the structure of FDS and to constructs within FDS (such as files of information or the part of FDS which interacts directly with the user). A guide to the commands available to FDS users is presented. A glossary of important terms, an index to terms, and a quick reference to the commands of FDS are included.

The Safety Analysis of Shipborne Ammunition in Fire Environment

NASA Astrophysics Data System (ADS)

Ren, Junpeng; Wang, Xudong; Yue, Pengfei

2017-12-01

The safety of Ammunition has always been the focus of national military science and technology issues. And fire is one of the major safety threats to the ship’s ammunition storage environment, In this paper, Mk-82 shipborne aviation bomb has been taken as the study object, simulated the whole process of fire by using the FDS (Fire Detection System) software. According to the simulation results of FDS, ANSYS software was used to simulate the temperature field of Mk-82 carrier-based aviation bomb under fire environment, and the safety of aviation bomb in fire environment was analyzed. The result shows that the aviation bombs under the fire environment can occur the combustion or explosion after 70s constant cook-off, and it was a huge threat to the ship security.

Study of large Forbush decreases in cosmic-ray intensity observed during solar cycle 23 and 24

NASA Astrophysics Data System (ADS)

Kumar, Anand; Badruddin, B.

2016-07-01

Neutron monitors at different geomagnetic latitude and longitude of Earth measure the cosmic-ray intensity with high precision. Sudden decreases in cosmic-ray intensity within few hours and slow recovery to pre-decrease level within a few days (Forbush decreases) are observed in neutron monitor data. We identify large-amplitude Forbush decreases (FDs), using high counting rate neutron monitor data, that occurred during previous solar cycle 23 (1995-2009) and current solar cycle 24 (2010-2015). We then search for the solar sources and the interplanetary structures responsible for these decreases. We attempt to find the relative importance of various interplanetary plasma and field parameters and the physical mechanism(s) responsible for FDs of varying amplitudes. We analyze a number of interplanetary plasma and field parameters, during both the phases (main and recovery) of FDs. The interplanetary plasma and field data analyzed in this study are the solar-wind velocity, the interplanetary magnetic field, its fluctuations, interplanetary electric field and the time variation of interplanetary electric potential. For monitoring the changes in interplanetary plasma/field conditions during the development of FDs, we also utilize plasma density, temperature and plasma beta, dynamic pressure and Mach number during the passage of interplanetary structures responsible for FDs. In addition to their amplitude, we study the recovery of FDs in detail after determining the time constant during their recovery by exponential fit to the data. As the solar magnetic polarity reversed during the maximum phase of solar cycle 23 (in the year 2000), we study the differences in amplitude, time constant of recovery and plasma/field condition to search for the polarity dependent effects, if any, on the amplitude and recovery of FDs due to implication for the models suggested to explain the Forbush decrease phenomena. The implications of these results are discussed.

Experimental and Numerical Analysis of the Cooling Performance of Water Spraying Systems during a Fire

PubMed Central

Chen, YaoHan; Su, ChungHwei; Tseng, JoMing; Li, WunJie

2015-01-01

The water spray systems are effective protection systems in the confined or unconfined spaces to avoid the damage to building structures since the high temperature when fires occur. NFPA 15 and 502 have suggested respectively that the factories or vehicle tunnels install water spray systems to protect the machinery and structures. This study discussed the cooling effect of water spray systems in experimental and numerical analyses. The actual combustion of woods were compared with the numerical simulations. The results showed that although the flame continued, the cooling effects by water spraying process within 120 seconds were obvious. The results also indicated that the simulation results of the fifth version Fire Dynamics Simulator (FDS) overestimated the space temperature before water spraying in the case of the same water spray system. PMID:25723519

Overview of ISS U.S. Fire Detection and Suppression System

NASA Technical Reports Server (NTRS)

Whitaker, Alana

2003-01-01

This paper presents a general overview of the International Space Station's Fire Detection and Suppression System. The topics include: 1) Introduction to Fire Detection and Suppression (FDS); 2) Description of (FDS) Subsystems; 3) FDS System Component Location and Status; 4) FDS System Capabilities; 5) FDS Automatic and Manual Response; 6) Post Fire Atmosphere Restoration and Air Quality Assessment; and 7) FDS Research Needs. This paper is in viewgraph form.

The Dynamics of Voluntary Force Production in Afferented Muscle Influence Involuntary Tremor

PubMed Central

Laine, Christopher M.; Nagamori, Akira; Valero-Cuevas, Francisco J.

2016-01-01

Voluntary control of force is always marked by some degree of error and unsteadiness. Both neural and mechanical factors contribute to these fluctuations, but how they interact to produce them is poorly understood. In this study, we identify and characterize a previously undescribed neuromechanical interaction where the dynamics of voluntary force production suffice to generate involuntary tremor. Specifically, participants were asked to produce isometric force with the index finger and use visual feedback to track a sinusoidal target spanning 5–9% of each individual's maximal voluntary force level. Force fluctuations and EMG activity over the flexor digitorum superficialis (FDS) muscle were recorded and their frequency content was analyzed as a function of target phase. Force variability in either the 1–5 or 6–15 Hz frequency ranges tended to be largest at the peaks and valleys of the target sinusoid. In those same periods, FDS EMG activity was synchronized with force fluctuations. We then constructed a physiologically-realistic computer simulation in which a muscle-tendon complex was set inside of a feedback-driven control loop. Surprisingly, the model sufficed to produce phase-dependent modulation of tremor similar to that observed in humans. Further, the gain of afferent feedback from muscle spindles was critical for appropriately amplifying and shaping this tremor. We suggest that the experimentally-induced tremor may represent the response of a viscoelastic muscle-tendon system to dynamic drive, and therefore does not fall into known categories of tremor generation, such as tremorogenic descending drive, stretch-reflex loop oscillations, motor unit behavior, or mechanical resonance. Our findings motivate future efforts to understand tremor from a perspective that considers neuromechanical coupling within the context of closed-loop control. The strategy of combining experimental recordings with physiologically-sound simulations will enable thorough exploration of neural and mechanical contributions to force control in health and disease. PMID:27594832

STS-26 simulation activities in JSC Mission Control Center (MCC)

NASA Technical Reports Server (NTRS)

1987-01-01

In JSC Mission Control Center (MCC) Bldg 30 Flight Control Room (FCR), flight directors (FDs) Lee Briscoe (left) and Charles W. Shaw, seated at FD console, view front visual display monitors during STS-26 simulations in progress between MCC and JSC Mission Simulation and Training Facility Bldg 5 fixed-base (FB) shuttle mission simulator (SMS).

A numerical study on the influence of slope and curvature on smoke flow in special section tunnel with natural ventilation

NASA Astrophysics Data System (ADS)

Wang, Wenzhou; Zhou, Xianping; Liu, Zhigang; Liu, Ya; Liu, Wanfu; Hong, Li

2017-09-01

In this study, a special section tunnel model was established by using FDS (Fire Dynamics Simulator). The influences of lope and curvature on smoke flow under natural ventilation have been studied. The results showed that under the condition of natural ventilation, the slope has some influences on the smoke flow in special section tunnel. The smoke spreading speed is accelerated along the upstream direction and decrease along the downstream direction due to buoyancy effect of slope. The steeper the tunnel, the more obvious the buoyancy effect. The curvature has little effect on the flow of flue gas.

Consequence modeling using the fire dynamics simulator.

PubMed

Ryder, Noah L; Sutula, Jason A; Schemel, Christopher F; Hamer, Andrew J; Van Brunt, Vincent

2004-11-11

The use of Computational Fluid Dynamics (CFD) and in particular Large Eddy Simulation (LES) codes to model fires provides an efficient tool for the prediction of large-scale effects that include plume characteristics, combustion product dispersion, and heat effects to adjacent objects. This paper illustrates the strengths of the Fire Dynamics Simulator (FDS), an LES code developed by the National Institute of Standards and Technology (NIST), through several small and large-scale validation runs and process safety applications. The paper presents two fire experiments--a small room fire and a large (15 m diameter) pool fire. The model results are compared to experimental data and demonstrate good agreement between the models and data. The validation work is then extended to demonstrate applicability to process safety concerns by detailing a model of a tank farm fire and a model of the ignition of a gaseous fuel in a confined space. In this simulation, a room was filled with propane, given time to disperse, and was then ignited. The model yields accurate results of the dispersion of the gas throughout the space. This information can be used to determine flammability and explosive limits in a space and can be used in subsequent models to determine the pressure and temperature waves that would result from an explosion. The model dispersion results were compared to an experiment performed by Factory Mutual. Using the above examples, this paper will demonstrate that FDS is ideally suited to build realistic models of process geometries in which large scale explosion and fire failure risks can be evaluated with several distinct advantages over more traditional CFD codes. Namely transient solutions to fire and explosion growth can be produced with less sophisticated hardware (lower cost) than needed for traditional CFD codes (PC type computer verses UNIX workstation) and can be solved for longer time histories (on the order of hundreds of seconds of computed time) with minimal computer resources and length of model run. Additionally results that are produced can be analyzed, viewed, and tabulated during and following a model run within a PC environment. There are some tradeoffs, however, as rapid computations in PC's may require a sacrifice in the grid resolution or in the sub-grid modeling, depending on the size of the geometry modeled.

Ventilation of Animal Shelters in Wildland Fire Scenarios

NASA Astrophysics Data System (ADS)

Bova, A. S.; Bohrer, G.; Dickinson, M. B.

2009-12-01

The effects of wildland fires on cavity-nesting birds and bats, as well as fossorial mammals and burrow-using reptiles, are of considerable interest to the fire management community. However, relatively little is known about the degree of protection afforded by various animal shelters in wildland fire events. We present results from our ongoing investigation, utilizing NIST’s Fire Dynamics Simulator (FDS) and experimental data, of the effectiveness of common shelter configurations in protecting animals from combustion products. We compare two sets of simulations with observed experimental results. In the first set, wind tunnel experiments on single-entry room ventilation by Larsen and Heiselberg (2008) were simulated in a large domain resolved into 10 cm cubic cells. The set of 24 simulations comprised all combinations of incident wind speeds of 1,3 and 5 m/s; angles of attack of 0, 45, 90 and 180 degrees from the horizontal normal to the entrance; and temperature differences of 0 and 10 degrees C between the building interior and exterior. Simulation results were in good agreement with experimental data, thus providing a validation of FDS code for further ventilation experiments. In the second set, a cubic simulation domain of ~1m on edge and resolved into 1 cm cubic cells, was set up to represent the experiments by Ar et al. (2004) of wind-induced ventilation of woodpecker cavities. As in the experiments, we simulated wind parallel and perpendicular to the cavity entrance with different mean forcing velocities, and monitored the rates of evacuation of a neutral-buoyancy tracer from the cavity. Simulated ventilation rates in many, though not all, cases fell within the range of experimental data. Reasons for these differences, which include vagueness in the experimental setup, will be discussed. Our simulations provide a tool to estimate the viability of an animal in a shelter as a function of the shelter geometry and the fire intensity. In addition to the above, we explore the role of turbulence and its effect on ventilation rates, especially in single-entrance shelters. The goal of this work is to provide engineering formulas to estimate the probable levels of harmful or irritating combustion products in animal shelters during wildland fires.

Heart rate variability (HRV) and muscular system activity (EMG) in cases of crash threat during simulated driving of a passenger car.

PubMed

Zużewicz, Krystyna; Roman-Liu, Danuta; Konarska, Maria; Bartuzi, Paweł; Matusiak, Krzysztof; Korczak, Dariusz; Lozia, Zbigniew; Guzek, Marek

2013-10-01

The aim of the study was to verify whether simultaneous responses from the muscular and circulatory system occur in the driver's body under simulated conditions of a crash threat. The study was carried out in a passenger car driving simulator. The crash was included in the driving test scenario developed in an urban setting. In the group of 22 young male subjects, two physiological signals - ECG and EMG were continuously recorded. The length of the RR interval in the ECG signal was assessed. A HRV analysis was performed in the time and frequency domains for 1-minute record segments at rest (seated position), during undisturbed driving as well as during and several minutes after the crash. For the left and right side muscles: m. trapezius (TR) and m. flexor digitorum superficialis (FDS), the EMG signal amplitude was determined. The percentage of maximal voluntary contraction (MVC) was compared during driving and during the crash. As for the ECG signal, it was found that in most of the drivers changes occurred in the parameter values reflecting HRV in the time domain. Significant changes were noted in the mean length of RR intervals (mRR). As for the EMG signal, the changes in the amplitude concerned the signal recorded from the FDS muscle. The changes in ECG and EMG were simultaneous in half of the cases. Such parameters as mRR (ECG signal) and FDS-L amplitude (EMG signal) were the responses to accident risk. Under simulated conditions, responses from the circulatory and musculoskeletal systems are not always simultaneous. The results indicate that a more complete driver's response to a crash in road traffic is obtained based on parallel recording of two physiological signals (ECG and EMG).

Forward and Backward Digit Span Interaction With Race and IQ: Predictions from Jensen's Theory

ERIC Educational Resources Information Center

Jensen, Arthur R.; Figueroa, Richard A.

1975-01-01

From Jensen's two-level theory of mental abilities it was predicted that forward digit span (FDS) should correlate less with IQ than backward digit span (BDS), and age and race should interact with FDS-BDS, with FDS-BDS difference decreasing as a function of age and a greater white-black difference in BDS than in FDS. (Author/BJG)

Capabilities of current wildfire models when simulating topographical flow

NASA Astrophysics Data System (ADS)

Kochanski, A.; Jenkins, M.; Krueger, S. K.; McDermott, R.; Mell, W.

2009-12-01

Accurate predictions of the growth, spread and suppression of wild fires rely heavily on the correct prediction of the local wind conditions and the interactions between the fire and the local ambient airflow. Resolving local flows, often strongly affected by topographical features like hills, canyons and ridges, is a prerequisite for accurate simulation and prediction of fire behaviors. In this study, we present the results of high-resolution numerical simulations of the flow over a smooth hill, performed using (1) the NIST WFDS (WUI or Wildland-Urban-Interface version of the FDS or Fire Dynamic Simulator), and (2) the LES version of the NCAR Weather Research and Forecasting (WRF-LES) model. The WFDS model is in the initial stages of development for application to wind flow and fire spread over complex terrain. The focus of the talk is to assess how well simple topographical flow is represented by WRF-LES and the current version of WFDS. If sufficient progress has been made prior to the meeting then the importance of the discrepancies between the predicted and measured winds, in terms of simulated fire behavior, will be examined.

Pay for performance of Estonian family doctors and impact of different practice- and patient-related characteristics on a good outcome: A quantitative assessment.

PubMed

Merilind, Eero; Salupere, Rauno; Västra, Katrin; Kalda, Ruth

2016-01-01

Several practice- and patient-related characteristics are reported to have an influence on a good quality outcome. Estonia started the pay-for-performance (P4P) system for family doctors (FDs) in 2006. Every year the number of FDs participating in P4P has increased, but only half of the FDs achieved good outcome. The aim of this study was to find out which practice- and patient-related characteristics could have an impact on a good outcome. The study was conducted using the database from the Estonian Health Insurance Fund. All working FDs were divided into two groups (with "good" and "poor" outcomes) according their achievements in P4P. We chose characteristics which described structure (practice list size, number of doctors, composition of FDs list: age, number of chronically ill patients) during the observation period 2006-2012. During the observation period 2006-2012, the number of FDs with a good outcome in P4P increased from 6% (2006) to 53% (2012). The high number of FDs in primary care teams, longer experience of participation in P4P and the smaller number of patients on FDs' lists all have an impact on a good outcome. The number of chronically ill patients in FDs lists has no significant effect on an outcome, but P4P increases the number of disease-diagnosed patients. Different practice and patient-related characteristics have an impact on a good outcome. As workload increases, smaller lists of FDs patients or increased staff levels are needed in order to maintain a good outcome. Copyright © 2016 The Lithuanian University of Health Sciences. Production and hosting by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

Effects of Combined Treatment with Branched-Chain Amino Acids, Citric Acid, L-Carnitine, Coenzyme Q10, Zinc, and Various Vitamins in Tumor-Bearing Mice.

PubMed

Awa, Hiroko; Futamura, Akihiko; Higashiguchi, Takashi; Ito, Akihiro; Mori, Naoharu; Murai, Miyo; Ohara, Hiroshi; Chihara, Takeshi; Kaneko, Takaaki

2017-03-01

A functional dietary supplement (FDS) containing Coenzyme Q10, branched-chain amino acids and L-carnitine was administered to tumor-bearing mice, investigating its effects on tumor and muscle tissues. Experiment (A): B16 melanoma cells were implanted subcutaneously into the right side of the abdomen of 8- to 9-week-old C57BL/6J mice. The mice were divided into two groups: a FDS group that received oral administration of FDS (n=10), and a control group that received oral administration of glucose (n=10). The moribund condition was used as the endpoint, and median survival time was determined. Experiment (B): On day 21 after tumor implantation, tumors, soleus muscle, gastrocnemius muscle, and suprahyoid muscles were collected. Tumor and muscle weight and other aspects were evaluated in each group: FDS group (n=15) and control group (n=15). The median survival time was comparable (21 d in the FDS group vs. 18 d in the control group, p=0.30). However, cumulative food intake was significantly higher in the FDS group than the control group (p=0.011). Metastasis of melanoma to the lung was observed in the control group but not in the FDS group (p=0.043). The weight of the suprahyoid muscles was significantly higher in the FDS group than in the control group (p=0.0045). The weight of the tumor was significantly lower in the FDS group than in the control group (p=0.013). The results possibly suggest oral administration of FDS in tumor-bearing mice enhances the maintenance of suprahyoid muscles, resulting in an extended feeding period and suppression of tumor growth and metastasis.

Foundation doctors working at night: what training opportunities exist?

PubMed

Coomber, R; Smith, D; McGuinness, D; Shao, E; Soobrah, R; Frankel, A H

2014-07-01

Foundation Training is designed for doctors in their first two years of post-graduation. The number of foundation doctors (FD) in the UK working nights has reduced because of a perception that clinical supervision at night is unsatisfactory and that minimal training opportunities exist. We aimed to assess the value of night shifts to FDs and hypothesised that removing FDs from nights may be detrimental to training. Using a survey, we assessed the number of FDs working nights in London, FDs views on working nights and their supervision at night. We evaluated whether working at night, compared to daytime working provided opportunities to achieve foundation competencies. 83% (N = 2157/2593) of FDs completed the survey. Over 90% of FDs who worked nights felt that the experience they gained improved their ability to prioritise, make decisions and plan. FDs who worked nights reported higher scores for achieving competencies in history taking (2.67 vs. 2.51; p = 0.00), examination (2.72 vs. 2.59; p = 0.01) and resuscitation (2.27 vs. 1.96; p = 0.00). The majority (65%) felt adequately supervised. Our survey has demonstrated that FDs find working nights a valuable experience, providing important training opportunities, which are additional to those encountered during daytime working.

The Application of a Jet Fan for the Control of Air and Methane Streams Mixing at the Excavations Cross - The Results of Numerical Simulation

NASA Astrophysics Data System (ADS)

Wrona, Paweł; Różański, Zenon; Pach, Grzegorz; Domagała, Lech

2016-09-01

The paper presents the results of numerical simulations into the distribution of methane concentration at the intersection of two excavations with a fan (turned on) giving the air stream to the area of the crossing. Assumed case represents emergency situation related to the unexpected flow of methane from an excavation and its mixing with fresh air. It is possible when sudden gas outburst takes place, methane leaks from methane drainage system or gas leaks out the pipelines of underground coal gasification devices. Three options were considered - corresponding to three different speeds of the jet fan. They represent three stages of fan work. First - low air speed is forced by a pneumatic fan, when electricity is cut off after high methane concentration detection. Medium speed can be forced by pneumatic-electric device when methane concentration allows to turn on the electricity. Third, the highest speed is for electric fans. Simulations were carried out in the Fire Dynamics Simulator (FDS) belongs to the group of programs Computational Fluid Dynamics (CFD). The governing equations are being solved in a numerical way. It was shown that proposed solution allows partial dilution of methane in every variant of speed what should allow escape of the miners from hazardous area.

A useful strategy based on chromatographic data combined with quality-by-design approach for food analysis applications. The case study of furanic derivatives in sugarcane honey.

PubMed

Silva, Pedro; Silva, Catarina L; Perestrelo, Rosa; Nunes, Fernando M; Câmara, José S

2017-10-20

Sugarcane honey (SCH) is one of the Madeira Island products par excellence and it is now popular worldwide. Its sui generis and peculiar sensory properties, explained by a variety of volatile compounds including furanic derivatives (FDs), arise mainly from manufacturing and storage conditions. A simple high-throughput approach based on semi-automatic microextraction by packed sorbent (MEPS) combined with ultra-high performance liquid chromatography (UHPLC) was developed and validated for identification and quantification of target FDs in sugarcane honey. A Quality-by-Design (QbD) approach was used as a powerful strategy to optimize analytical conditions for high throughput analysis of FDs in complex sugar-rich food matrices. The optimum point into MEPS-Method Operable Design: Region (MODR) was obtained with R-CX sorbent, acetonitrile (ACN) as elution solvent, three loading cycles and 500μL of sample volume. The optimum point into UHPLC-MODR was obtained with a CORTECS column operating at a temperature of 50°C, ACN as eluent and a flow rate of 125μLmin -1 . The robustness was demonstrated by Monte Carlo simulation and capability analysis for estimation of residual errors. The concentration-response relationship for all FDs were described by polynomial function models, being confirmed by Fisher variance (F-test). The% recoveries were in a range of 91.9-112.1%. Good method precision was observed, yielding relative standard deviations (RSDs) less than 4.9% for repeatability and 8.8% for intermediate precision. The limits of quantitation for the analytes ranged from 30.6 to 737.7μgkg -1 . The MEPS R-CX /UHPLC CORTECS -PDA method revealed an effective and potential analytical tool for SCH authenticity control based on target analysis of FDs allowing a strict control and differentiation from other similar or adulterated products. Copyright © 2017 Elsevier B.V. All rights reserved.

Effects of flexor-pronator muscle loading on valgus stability of the elbow with an intact, stretched, and resected medial ulnar collateral ligament.

PubMed

Udall, John H; Fitzpatrick, Michael J; McGarry, Michelle H; Leba, Thu-Ba; Lee, Thay Q

2009-01-01

The medial ulnar collateral ligament (MUCL) is an important passive stabilizer to the valgus stresses that athletes experience during overhead throwing motion. However, the role of the flexor-pronator muscles as active stabilizers to valgus stress is not well defined in the literature. The objectives of this study were to quantify the relative contribution of the individual flexor-pronator muscles to valgus stability of the elbow and how this relationship was affected by ligament status. A custom elbow testing system and Microscribe 3DLX were used for biomechanical testing. Flexor-pronator muscles were loaded to simulate contraction, and the valgus angle of the elbow was measured in eight cadaveric specimens at 30 degrees , 60 degrees , and 90 degrees of elbow flexion with 3 different valgus torques applied to the forearm. Loads based on muscle cross-sectional area were applied to the flexor carpi ulnaris (FCU), flexor digitorum superficialis (FDS), and pronator teres (PT). The effect of each muscle was evaluated by unloading the individual muscle while the other 2 remained loaded, resulting in 5 loading conditions: no muscles loaded, all muscles loaded, unloaded FCU, unloaded FDS, and unloaded PT. Valgus angle was measured for 3 MUCL ligament conditions: intact, stretched, and cut. The effect of muscle loading on valgus angle was similar for each ligament condition. Loading the flexor-pronator muscles significantly decreased valgus angle of the elbow in all testing conditions (P < .01). Unloading the FDS significantly increased valgus angle compared to all muscles loaded in all testing conditions (P < .016). Unloading the FCU and PT significantly increased valgus angle in less than half of the testing conditions. The FDS, PT, and FCU are all active stabilizers of the elbow to valgus stress. The FDS is the biggest contributor amongst the flexor-pronator muscles.

In vitro cavity and crown preparations and direct restorations: A comparison of performance at the start and end of the FD programme.

PubMed

Burke, F J T; Ravaghi, V; Mackenzie, L; Priest, N; Falcon, H C

2017-04-21

Aim To assess the performance and thereby the progress of the FDs when they carried out a number of simulated clinical exercises at the start and at the end of their FD year.Methods A standardised simulated clinical restorative dentistry training exercise was carried out by a group of 61 recently qualified dental graduates undertaking a 12 months' duration foundation training programme in England, at both the start and end of the programme. Participants completed a Class II cavity preparation and amalgam restoration, a Class IV composite resin restoration and two preparations for a porcelain-metal full crown. The completed preparations and restorations were independently assessed by an experienced consultant in restorative dentistry, using a scoring system based on previously validated criteria. The data were subjected to statistical analysis.Results There was wide variation in individual performance. Overall, there was a small but not statistically significant improvement in performance by the end of the programme. A statistically significant improvement was observed for the amalgam preparation and restoration, and, overall, for one of the five geographical sub-groups in the study. Possible reasons for the variable performance and improvement are discussed.Conclusions There was variability in the performance of the FDs. The operative performance of FDs at the commencement and end of their FD year indicated an overall moderately improved performance over the year and a statistically significant improvement in their performance with regard to amalgam restoration.

Changes in characteristics and management of Asian and Anglo-Celts with type 2 diabetes over a 15-year period in an urban Australian community: The Fremantle Diabetes Study.

PubMed

Tan, Eva D D; Davis, Wendy A; Davis, Timothy M E

2016-01-01

The aim of the present study was to determine temporal changes in characteristics and management of Asians with type 2 diabetes (T2D) compared with those of the majority Anglo-Celt (AC) patients in an urban Australian community. Cross-sectional data from the observational Fremantle Diabetes Study (FDS) collected in 1993-96 (Phase I; FDS1) and 2008-11 (Phase II; FDS2) were analyzed for patients classified as Asian (n = 44 and 65 in FDS1 and FDS2, respectively) or AC (n = 796 and 793, respectively). Between-group differences in changes in key variables between FDS phases were analyzed by generalized linear modeling with adjustment for age and gender. Asians patients were significantly younger at diagnosis and recruitment and had a lower body mass index and smaller waist circumference than the AC participants in both FDS phases. They were also less likely to be treated for hypertension. Cardiovascular risk factors and their management and macrovascular complications were similar in the two groups over time. A greater propensity to retinopathy with Asian ethnicity in FDS1 (27.3% vs 13.5%; P = 0.23) was attenuated in FDS2 (23.7% vs 19.0%; P = 0.39). Asians had a significantly lower prevalence of peripheral sensory neuropathy in FDS2 (33.8% vs 63.3%; P < 0.001; adjusted P = 0.011 for between-group temporal change). There were persistent differences between the phenotypic features of Asian migrants with T2D versus AC patients in an Australian urban community over 15 years of follow-up, but management of diabetes and non-glycemic risk factors remained comparable. Ethnicity-specific differences in susceptibility to microvascular complications should be considered in clinical management. © 2015 Ruijin Hospital, Shanghai Jiaotong University School of Medicine and Wiley Publishing Asia Pty Ltd.

Organic photochromics for spatial light modulation

NASA Astrophysics Data System (ADS)

Kirkby, C. J. G.; Bennion, I.

1986-02-01

The feasibility of using fulgide derivatives (FD), a class of thermally stable, fatigue-free photochromic materials (PM), as optically addressed spatial light modulators (SLIM) is analyzed. Photochromism is the property of a material that changes from one physicochemical state to another due to the impingement of light. The PMs are low-resolution but exhibit no granularity as photographic films do, therefore permitting the use of PMs as data or image recording media with direct-read-after-write capability. It is known that the properties of the FDs (of dimethyl succinic anhydride), i.e., the fatigue, thermal stability and absorption band location, can be tailored by control of the location of two of the oxygen links at two locations on the molecule. Manipulating the absorption spectra also allows manipulation of the refractive index, ergo the SLIM capability of the FDs. Molecular substitutions have proven effective for adjustments of the wavelength sensitivities of the FDs. Film thicknesses of 3-10 microns have been shown capable of supporting a practical resolution limit of 100-200 line pairs/mm, a 30 dB dynamic range, a Fourier plane SNR of 50, and an image recycle time of 40 msec.

Quantitative computational infrared imaging of buoyant diffusion flames

NASA Astrophysics Data System (ADS)

Newale, Ashish S.

Studies of infrared radiation from turbulent buoyant diffusion flames impinging on structural elements have applications to the development of fire models. A numerical and experimental study of radiation from buoyant diffusion flames with and without impingement on a flat plate is reported. Quantitative images of the radiation intensity from the flames are acquired using a high speed infrared camera. Large eddy simulations are performed using fire dynamics simulator (FDS version 6). The species concentrations and temperature from the simulations are used in conjunction with a narrow-band radiation model (RADCAL) to solve the radiative transfer equation. The computed infrared radiation intensities rendered in the form of images and compared with the measurements. The measured and computed radiation intensities reveal necking and bulging with a characteristic frequency of 7.1 Hz which is in agreement with previous empirical correlations. The results demonstrate the effects of stagnation point boundary layer on the upstream buoyant shear layer. The coupling between these two shear layers presents a model problem for sub-grid scale modeling necessary for future large eddy simulations.

Numerical simulation of steady and unsteady asymmetric vortical flow

NASA Technical Reports Server (NTRS)

Kandil, Osama A.; Wong, Tin-Chee; Liu, C. H.

1992-01-01

The unsteady, compressible, thin-layer, Navier-Stokes (NS) equations are solved to simulate steady and unsteady, asymmetric, vortical laminar flow around cones at high incidences and supersonic Mach numbers. The equations are solved by using an implicit, upwind, flux-difference splitting (FDS), finite-volume scheme. The locally conical flow assumption is used and the solutions are obtained by forcing the conserved components of the flowfield vector to be equal at two axial stations located at 0.95 and 1.0. Computational examples cover steady and unsteady asymmetric flows around a circular cone and its control using side strakes. The unsteady asymmetric flow solution around the circular cone has also been validated using the upwind, flux-vector splitting (FVS) scheme with the thin-layer NS equations and the upwind FDS with the full NS equations. The results are in excellent agreement with each other. Unsteady asymmetric flows are also presented for elliptic- and diamond-section cones, which model asymmetric vortex shedding around round- and sharp-edged delta winds.

Control of Drug Dissolution Rate from Film Dosage Forms Containing Valsartan.

PubMed

Murata, Yoshifumi; Kofuji, Kyoko; Maida, Chieko

2016-01-01

Film dosage forms (FDs) containing valsartan (VST), a popular antihypertensive drug, were prepared using a casting method with sodium alginate and other polysaccharides as the film base. Drug dissolution profiles of the FDs were investigated in limited medium. The FDs were 170-200 μm thick and were easy to handle. All FDs immediately swelled and disintegrated in the medium. About 23% of the VST incorporated into the FD prepared with 1.5% sodium alginate dissolved at 5 min. The initial dissolution rate of VST increased upon the addition of chitosan to the film base; this effect was not observed in the case of chitin. On the other hand, the rate apparently decreased upon modification with alginic acid. In addition, the solubility of VST in the dissolution medium was changed by the addition of chitosan or alginic acid. FDs prepared with polysaccharides are useful for simplifying the administration of drugs to patients, and the drug dissolution rate from FDs can be controlled by modification.

Technique of Dynamic Flexor Digitorum Superficialis Transfer to Lateral Bands for Proximal Interphalangeal Joint Deformity Correction in Severe Dupuytren Disease.

PubMed

Schreck, Michael J; Holbrook, Hayden S; Koman, L Andrew

2018-02-01

Pseudo-boutonniere deformity is an uncommon complication from long-standing proximal interphalangeal (PIP) joint contracture in Dupuytren disease. Prolonged flexion contracture of the PIP joint can lead to central slip attenuation and resultant imbalances in the extensor mechanism. We present a technique of flexor digitorum superficialis (FDS) tendon transfer to the lateral bands to correct pseudo-boutonniere deformity at the time of palmar fasciectomy for the treatment of Dupuytren disease. The FDS tendon is transferred from volar to dorsal through the lumbrical canal and sutured into the dorsally mobilized lateral bands. This technique presents an approach to the repair of pseudo-boutonniere deformity in Dupuytren disease. Copyright © 2018 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

Some properties of flare-not-associated Forbush decreases

NASA Astrophysics Data System (ADS)

Iucci, N.; Parisi, M.; Signorini, C.; Storini, M.; Villoresi, G.

1984-07-01

All non flare-associated Forbush decreases (N Ass Fds) over the period 1957 to 1979 are investigated. The connection between N Ass Fds occurrence and the central meridian passage of strong active regions producing great flare associated Fds shows the flare origin of the N Ass Fds. The interplanetary perturbations at the eastern and western boundaries of the modulated region are found to be long living corotating structures. These structures mark the boundaries of the region in which the (1 to 4 Mev) protons accelerated by interplanetary flare generated shocks are confined.

Can family or replacement blood donors become regular volunteer donors?

PubMed

Asenso-Mensah, Kwame; Achina, Gifty; Appiah, Rita; Owusu-Ofori, Shirley; Allain, Jean-Pierre

2014-03-01

In sub-Saharan Africa (SSA) confirmed viral marker prevalence between family donors (FDs) and first-time volunteer nonremunerated donors (VNRDs) is similar. In a blood service collecting 10 units/1000 inhabitants, a questionnaire examined FD donation conditions and willingness of becoming repeat VNRDs. Four areas were explored: circumstances of visit to hospital, external pressure, experience of donating, and potential repeat donation. After donation and consent, research assistants administered 25 questions and, according to literacy, helped with translation and completion. Of 513 FDs, three-fourths were males (median age, 27 years). Only 1.3% were unemployed and more than 50% were students or teachers. Ties with hospitalized patient were family (76%), friends (13%), colleagues, or sharing place of worship (10%). Donating blood was the reason for visiting in 16.8% and 20.9% had previously donated blood probably as FDs. In one-third of FDs, the family asked for donation of which 10% was pressured by the unjustified reason that not donating was endangering the patient's life. For two-thirds of FDs, donation was given "because individuals were asked." Donation was a positive experience for 77% of donors, 62% being interested in predonation testing. Repeating donation was acceptable for 99% of 79% FDs answering. FDs are active in the population, are willing to donate blood if asked, are submitted to little pressure, do not receive incentives, and accept repeat donation. Except for circumstances of donation, FDs are not different from VNRDs and more directly motivated. They constitute a legitimate and important source to improve the blood supply in SSA. © 2013 American Association of Blood Banks.

33 CFR 147.833 - Na Kika FDS safety zone.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Na Kika FDS safety zone. 147.833 Section 147.833 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OUTER CONTINENTAL SHELF ACTIVITIES SAFETY ZONES § 147.833 Na Kika FDS safety zone. (a) Description. Na...

33 CFR 147.833 - Na Kika FDS safety zone.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Na Kika FDS safety zone. 147.833 Section 147.833 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OUTER CONTINENTAL SHELF ACTIVITIES SAFETY ZONES § 147.833 Na Kika FDS safety zone. (a) Description. Na...

Visualization and manipulating the image of a formal data structure (FDS)-based database

NASA Astrophysics Data System (ADS)

Verdiesen, Franc; de Hoop, Sylvia; Molenaar, Martien

1994-08-01

A vector map is a terrain representation with a vector-structured geometry. Molenaar formulated an object-oriented formal data structure for 3D single valued vector maps. This FDS is implemented in a database (Oracle). In this study we describe a methodology for visualizing a FDS-based database and manipulating the image. A data set retrieved by querying the database is converted into an import file for a drawing application. An objective of this study is that an end-user can alter and add terrain objects in the image. The drawing application creates an export file, that is compared with the import file. Differences between these files result in updating the database which involves checks on consistency. In this study Autocad is used for visualizing and manipulating the image of the data set. A computer program has been written for the data exchange and conversion between Oracle and Autocad. The data structure of the FDS is compared to the data structure of Autocad and the data of the FDS is converted into the structure of Autocad equal to the FDS.

A Numerical Study of Forbush Decreases with a 3D Cosmic-Ray Modulation Model Based on an SDE Approach

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

Luo, Xi; Feng, Xueshang; Potgieter, Marius S.

Based on the reduced diffusion mechanism for producing Forbush decreases (Fds) in the heliosphere, we constructed a three-dimensional (3D) diffusion barrier, and by incorporating it into a stochastic differential equation (SDE) based time-dependent, cosmic-ray transport model, a 3D numerical model for simulating Fds is built and applied to a period of relatively quiet solar activity. This SDE model generally corroborates previous Fd simulations concerning the effects of the solar magnetic polarity, the tilt angle of the heliospheric current sheet (HCS), and cosmic-ray particle energy. Because the modulation processes in this 3D model are multi-directional, the barrier’s geometrical features affect themore » intensity profiles of Fds differently. We find that both the latitudinal and longitudinal extent of the barrier have relatively fewer effects on these profiles than its radial extent and the level of decreased diffusion inside the disturbance. We find, with the 3D approach, that the HCS rotational motion causes the relative location from the observation point to the HCS to vary, so that a periodic pattern appears in the cosmic-ray intensity at the observing location. Correspondingly, the magnitude and recovery time of an Fd change, and the recovering intensity profile contains oscillation as well. Investigating the Fd magnitude variation with heliocentric radial distance, we find that the magnitude decreases overall and, additionally, that the Fd magnitude exhibits an oscillating pattern as the radial distance increases, which coincides well with the wavy profile of the HCS under quiet solar modulation conditions.« less

Freeze-Dried Strawberries Lower Serum Cholesterol and Lipid Peroxidation in Adults with Abdominal Adiposity and Elevated Serum Lipids123

PubMed Central

Basu, Arpita; Betts, Nancy M.; Nguyen, Angel; Newman, Emily D.; Fu, Dongxu; Lyons, Timothy J.

2014-01-01

Dietary flavonoid intake, especially berry flavonoids, has been associated with reduced risks of cardiovascular disease (CVD) in large prospective cohorts. Few clinical studies have examined the effects of dietary berries on CVD risk factors. We examined the hypothesis that freeze-dried strawberries (FDS) improve lipid and lipoprotein profiles and lower biomarkers of inflammation and lipid oxidation in adults with abdominal adiposity and elevated serum lipids. In a randomized dose-response controlled trial, 60 volunteers [5 men and 55 women; aged 49 ± 10 y; BMI: 36 ± 5 kg/m2 (means ± SDs)] were assigned to consume 1 of the following 4 beverages for 12 wk: 1) low-dose FDS (LD-FDS; 25 g/d); 2) low-dose control (LD-C); 3) high-dose FDS (HD-FDS; 50 g/d); and 4) high-dose control (HD-C). Control beverages were matched for calories and total fiber. Blood draws, anthropometrics, blood pressure, and dietary data were collected at screening (0 wk) and after 12-wk intervention. Dose-response analyses revealed significantly greater decreases in serum total and LDL cholesterol and nuclear magnetic resonance (NMR)–derived small LDL particle concentration in HD-FDS [33 ± 6 mg/dL, 28 ± 7 mg/dL, and 301 ± 78 nmol/L, respectively (means ± SEMs)] vs. LD-FDS (−3 ± 11 mg/dL, −3 ± 9 mg/dL, and −28 ± 124 nmol/L, respectively) over 12 wk (0–12 wk; all P < 0.05). Compared with controls, only the decreases in total and LDL cholesterol in HD-FDS remained significant vs. HD-C (0.7 ± 12 and 1.4 ± 9 mg/dL, respectively) over 12 wk (0–12 wk; all P < 0.05). Both doses of strawberries showed a similar decrease in serum malondialdehyde at 12 wk (LD-FDS: 1.3 ± 0.2 μmol/L; HD-FDS: 1.2 ± 0.1 μmol/L) vs. controls (LD-C: 2.1 ± 0.2 μmol/L; HD-C: 2.3 ± 0.2 μmol/L) (P < 0.05). In general, strawberry intervention did not affect any measures of adiposity, blood pressure, glycemia, and serum concentrations of HDL cholesterol and triglycerides, C-reactive protein, and adhesion molecules. Thus, HD-FDS exerted greater effects in lowering serum total and LDL cholesterol and NMR-derived small LDL particles vs. LD-FDS in the 12-wk study. These findings warrant additional investigation in larger trials. This trial was registered at clinicaltrials.gov as NCT01883401. PMID:24670970

ARES Modeling of High-foot Implosions (NNSA Milestone #5466)

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

Hurricane, O. A.

ARES “capsule only” simulations demonstrated results of applying an ASC code to a suite of high-foot ICF implosion experiments. While a capability to apply an asymmetric FDS drive to the capsule-only model using add-on Python routines exists, it was not exercised here. The ARES simulation results resemble the results from HYDRA simulations documented in A. Kritcher, et al., Phys. Plasmas, 23, 052709 (2016); namely, 1D simulation and data are in reasonable agreement for the lowest velocity experiments, but diverge from each other at higher velocities.

Measurements of Forbush decreases at Mars: both by MSL on ground and by MAVEN in orbit

NASA Astrophysics Data System (ADS)

Guo, Jingnan; Lillis, Robert; Wimmer-Schweingruber, Robert F.; Zeitlin, Cary; Simonson, Patrick; Rahmati, Ali; Posner, Arik; Papaioannou, Athanasios; Lundt, Niklas; Lee, Christina O.; Larson, Davin; Halekas, Jasper; Hassler, Donald M.; Ehresmann, Bent; Dunn, Patrick; Böttcher, Stephan

2018-04-01

The Radiation Assessment Detector (RAD), on board Mars Science Laboratory's (MSL) Curiosity rover, has been measuring ground level particle fluxes along with the radiation dose rate at the surface of Mars since August 2012. Similar to neutron monitors at Earth, RAD sees many Forbush decreases (FDs) in the galactic cosmic ray (GCR) induced surface fluxes and dose rates. These FDs are associated with coronal mass ejections (CMEs) and/or stream/corotating interaction regions (SIRs/CIRs). Orbiting above the Martian atmosphere, the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft has also been monitoring space weather conditions at Mars since September 2014. The penetrating particle flux channels in the solar energetic particle (SEP) instrument onboard MAVEN can also be employed to detect FDs. For the first time, we study the statistics and properties of a list of FDs observed in-situ at Mars, seen both on the surface by MSL/RAD and in orbit detected by the MAVEN/SEP instrument. Such a list of FDs can be used for studying interplanetary coronal mass ejections (ICME) propagation and SIR evolution through the inner heliosphere. The magnitudes of different FDs can be well-fitted by a power-law distribution. The systematic difference between the magnitudes of the FDs within and outside the Martian atmosphere may be mostly attributed to the energy-dependent modulation of the GCR particles by both the pass-by ICMEs/SIRs and the Martian atmosphere.

Organizational structure of the Croatian family practice: a longitudinal study based on routinely collected data.

PubMed

Keglević, Mladenka Vrcić; Balint, Ines; Cvetković, Ivica; Gaćina, Ana

2014-12-01

This study was undertaken with the main aim of determining the trends in the number of family doctors' (FD), gender and educational structure, working status and the number of patients per FD between 1995 and 2013. As the main source of data collection served the Croatian Health Service Yearbooks and Croatian Health Insurance Fund (CHIF) databases on practices and FDs contracting in 2013. Obtained results indicated that the number of contracted FDs increased until 2007, then decreased, and again increased until 2350 in 2013. Average number of patients on FDs list was 1987 in 2012. Less than 50% FDs were specialist in family medicine, 70.3% of them were self-employed with the CHIF contract, and 81% were women. 123 practices planned by the Network did not have contracting FD in 2013. The lack of FDs, the huge number of patients over the standard number, and the location of the missing practices within the rural communities, together make Croatian FM practices less accessible.

Antibacterial and antifungal activities from Siamese crocodile blood.

PubMed

Leelawongtawon, Ratree; Siruntawineti, Jindawan; Chaeychomsri, Win; Sattaponpan, Chisanucha

2010-12-01

To evaluate the in vitro antimicrobial activity of the Siamese crocodile blood against bacteria and fungi. Thirty Siamese crocodile blood samples including freeze dried whole blood (FDWB), fresh serum (FS), and freeze dried serum (FDS) were evaluated for antimicrobial susceptibility and MIC values against ATCC-registered strains of nine bacterial species and two fungal species and one fungus isolated from a clinical specimen, by using the standard broth microdilution method and a modified resazurin microtiter plate assay. The result showed that FS (80 mg/ml) and FDS (100 mg/ml) inhibited Gram negative bacteria including Enterobacter aerogenes ATCC 13048, Escherichia coli ATCC 25922, Klebsiella pneumoniae ATCC 27736, Salmonella typhimurium ATCC 13311 and Pseudomonas aeruginosa ATCC 27853 with the susceptibility rate at 23.30%, 10.00%, 40.00%, 70.00%, and 86.67%, respectively for FS, and 30.00%, 10.00%, 43.33%, 76.67% and 90.00%, respectively for FDS. The MIC and MBC were in the range of 12.50-100.00 mg/ml and 25.00-100.00 mg/m1 respectively. FS and FDS also inhibited Cryptococcus neoformans 250309 and Aspergillus niger with the susceptibility rate at 90.00% and 80.00%, respectively for FS and 100.00% and 83.33%, respectively for FDS. The MIC was in the range of 25.00-100.00 mg/ml. However, FS and FDS did not inhibit Gram positive bacteria and did not kill fungi. FDWB (100 mg/ml) could neither inhibit bacteria nor fungi. FS and FDS from Siamese crocodile exhibited potential antibacterial and antifungal activities.

Measurements of Forbush decreases at Mars: both by MSL on ground and by MAVEN in orbit

NASA Astrophysics Data System (ADS)

Guo, J.; Lillis, R. J.; Wimmer-Schweingruber, R. F.; Posner, A.; Halekas, J. S.; Zeitlin, C.; Hassler, D.; Lundt, N.; Simonson, P.; Lee, C. O.; Appel, J. K.; Boehm, E.; Boettcher, S. I.; Burmeister, S.; Brinza, D. E.; Cucinotta, F.; Ehresmann, B.; Lohf, H.; Martin-Garcia, C.; Matthiae, D.; Rafkin, S. C.; Reitz, G.; weigle, G., II

2017-12-01

The Radiation Assessment Detector (RAD), on board Mars Science Laboratory's (MSL) rover Curiosity, has been measuring the ground level particle fluxes along with the radiation dose rate at the surface of Mars since August 2012. Similar to neutron monitors at Earth, RAD sees many Forbush decreases (FDs) in the galactic cosmic ray (GCR) induced surface fluxes and dose rates. These FDs are associated with coronal mass ejections (CMEs) and/or streaming/corotating interaction regions (SIRs/CIRs). Orbiting above the Martian atmosphere, the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft has also been monitoring space weather conditions at Mars since its arrival in September 2014. The penetrating particle flux channel in the Solar Energetic Particle (SEP) instrument aboard can also be employed to detect FDs. For the first time, we study the statistics and properties of a list of FDs observed in-situ at Mars, seen both on the surface by MSL/RAD and in orbit detected by the MAVEN/SEP instrument. Such a list of FDs can be used for studying ICME propagations and SIR evolutions through the inner-heliosphere. The magnitudes of different FDs can be well-fitted by a power-law distribution. The systematic difference between the magnitudes of the FDs within and outside the Martian atmosphere may be attributed to the energy-dependent modulation of the GCR particles by not only the pass-by ICMEs/SIRs but also the Martian atmosphere. Such an effect has been modeled via transporting particles of differently modulated GCR spectra through the Martian atmosphere.

Bs and Ds decay constants in three-flavor lattice QCD.

PubMed

Wingate, Matthew; Davies, Christine T H; Gray, Alan; Lepage, G Peter; Shigemitsu, Junko

2004-04-23

Capitalizing on recent advances in lattice QCD, we present a calculation of the leptonic decay constants f(B(s)) and f(D(s)) that includes effects of one strange sea quark and two light sea quarks via an improved staggered action. By shedding the quenched approximation and the associated lattice scale uncertainty, lattice QCD greatly increases its predictive power. Nonrelativistic QCD is used to simulate heavy quarks with masses between 1.5m(c) and m(b). We arrive at the following results: f(B(s))=260+/-7+/-26+/-8+/-5 and f(D(s))=290+/-20+/-29+/-29+/-6 MeV. The first quoted error is the statistical uncertainty, and the rest estimate the sizes of higher order terms neglected in this calculation. All of these uncertainties are systematically improvable by including another order in the weak coupling expansion, the nonrelativistic expansion, or the Symanzik improvement program.

Measurement of the decay constant f(Ds+) using D(s+)-->l+ nu.

PubMed

Artuso, M; Blusk, S; Butt, J; Khalil, S; Li, J; Menaa, N; Mountain, R; Nisar, S; Randrianarivony, K; Sia, R; Skwarnicki, T; Stone, S; Wang, J C; Bonvicini, G; Cinabro, D; Dubrovin, M; Lincoln, A; Asner, D M; Edwards, K W; Naik, P; Briere, R A; Ferguson, T; Tatishvili, G; Vogel, H; Watkins, M E; Rosner, J L; Adam, N E; Alexander, J P; Cassel, D G; Duboscq, J E; Ehrlich, R; Fields, L; Gibbons, L; Gray, R; Gray, S W; Hartill, D L; Heltsley, B K; Hertz, D; Jones, C D; Kandaswamy, J; Kreinick, D L; Kuznetsov, V E; Mahlke-Krüger, H; Mohapatra, D; Onyisi, P U E; Patterson, J R; Peterson, D; Pivarski, J; Riley, D; Ryd, A; Sadoff, A J; Schwarthoff, H; Shi, X; Stroiney, S; Sun, W M; Wilksen, T; Athar, S B; Patel, R; Yelton, J; Rubin, P; Cawlfield, C; Eisenstein, B I; Karliner, I; Kim, D; Lowrey, N; Selen, M; White, E J; Wiss, J; Mitchell, R E; Shepherd, M R; Besson, D; Pedlar, T K; Cronin-Hennessy, D; Gao, K Y; Hietala, J; Kubota, Y; Klein, T; Lang, B W; Poling, R; Scott, A W; Smith, A; Zweber, P; Dobbs, S; Metreveli, Z; Seth, K K; Tomaradze, A; Ernst, J; Ecklund, K M; Severini, H; Love, W; Savinov, V; Aquines, O; Lopez, A; Mehrabyan, S; Mendez, H; Ramirez, J; Huang, G S; Miller, D H; Pavlunin, V; Sanghi, B; Shipsey, I P J; Xin, B; Adams, G S; Anderson, M; Cummings, J P; Danko, I; Hu, D; Moziak, B; Napolitano, J; He, Q; Insler, J; Muramatsu, H; Park, C S; Thorndike, E H; Yang, F

2007-08-17

We measure the decay constant f(Ds+) using the D(s+)-->l+ nu channel, where the l+ designates either a mu+ or a tau+, when the tau+ -->pi+ nu. Using both measurements we find f(Ds+)=274+/-13+/-7 MeV. Combining with our previous determination of f(D+), we compute the ratio f(Ds+)/f(D+)=1.23+/-0.11+/-0.04. We compare with theoretical estimates.

Combined Effects of Flow Diverting Strategies and Parent Artery Curvature on Aneurysmal Hemodynamics: A CFD Study

PubMed Central

Yu, Ying; Lv, Nan; Wang, Shengzhang; Karmonik, Christof; Liu, Jian-Min; Huang, Qinghai

2015-01-01

Purpose Flow diverters (FD) are increasingly being considered for treating large or giant wide-neck aneurysms. Clinical outcome is highly variable and depends on the type of aneurysm, the flow diverting device and treatment strategies. The objective of this study was to analyze the effect of different flow diverting strategies together with parent artery curvature variations on altering intra-aneurysmal hemodynamics. Methods Four ideal intracranial aneurysm models with different parent artery curvature were constructed. Computational fluid dynamics (CFD) simulations of the hemodynamics before and after applying five types of flow diverting strategies (single FD, single FD with 5% and 10% packing density of coils, two FDs with 25% and 50% overlapping rate) were performed. Changes in pressure, wall shear stress (WSS), relative residence time (RRT), inflow velocity and inflow volume rate were calculated and compared. Results Each flow diverting strategy resulted in enhancement of RRT and reduction of normalized mean WSS, inflow volume rate and inflow velocity in various levels. Among them, 50% overlapped FD induced most effective hemodynamic changes in RRT and inflow volume rate. The mean pressure only slightly decreased after treatment. Regardless of the kind of implantation of FD, the mean pressure, inflow volume rate and inflow velocity increased and the RRT decreased as the curvature of the parent artery increased. Conclusions Of all flow diverting strategies, overlapping FDs induced most favorable hemodynamic changes. Hemodynamics alterations post treatment were substantially influenced by parent artery curvature. Our results indicate the need of an individualized flow diverting strategy that is tailored for a specific aneurysm. PMID:26398847

Measurement of the Decay Constant fDs+ Using Ds+→l+ν

NASA Astrophysics Data System (ADS)

Artuso, M.; Blusk, S.; Butt, J.; Khalil, S.; Li, J.; Menaa, N.; Mountain, R.; Nisar, S.; Randrianarivony, K.; Sia, R.; Skwarnicki, T.; Stone, S.; Wang, J. C.; Bonvicini, G.; Cinabro, D.; Dubrovin, M.; Lincoln, A.; Asner, D. M.; Edwards, K. W.; Naik, P.; Briere, R. A.; Ferguson, T.; Tatishvili, G.; Vogel, H.; Watkins, M. E.; Rosner, J. L.; Adam, N. E.; Alexander, J. P.; Cassel, D. G.; Duboscq, J. E.; Ehrlich, R.; Fields, L.; Gibbons, L.; Gray, R.; Gray, S. W.; Hartill, D. L.; Heltsley, B. K.; Hertz, D.; Jones, C. D.; Kandaswamy, J.; Kreinick, D. L.; Kuznetsov, V. E.; Mahlke-Krüger, H.; Mohapatra, D.; Onyisi, P. U. E.; Patterson, J. R.; Peterson, D.; Pivarski, J.; Riley, D.; Ryd, A.; Sadoff, A. J.; Schwarthoff, H.; Shi, X.; Stroiney, S.; Sun, W. M.; Wilksen, T.; Athar, S. B.; Patel, R.; Yelton, J.; Rubin, P.; Cawlfield, C.; Eisenstein, B. I.; Karliner, I.; Kim, D.; Lowrey, N.; Selen, M.; White, E. J.; Wiss, J.; Mitchell, R. E.; Shepherd, M. R.; Besson, D.; Pedlar, T. K.; Cronin-Hennessy, D.; Gao, K. Y.; Hietala, J.; Kubota, Y.; Klein, T.; Lang, B. W.; Poling, R.; Scott, A. W.; Smith, A.; Zweber, P.; Dobbs, S.; Metreveli, Z.; Seth, K. K.; Tomaradze, A.; Ernst, J.; Ecklund, K. M.; Severini, H.; Love, W.; Savinov, V.; Aquines, O.; Lopez, A.; Mehrabyan, S.; Mendez, H.; Ramirez, J.; Huang, G. S.; Miller, D. H.; Pavlunin, V.; Sanghi, B.; Shipsey, I. P. J.; Xin, B.; Adams, G. S.; Anderson, M.; Cummings, J. P.; Danko, I.; Hu, D.; Moziak, B.; Napolitano, J.; He, Q.; Insler, J.; Muramatsu, H.; Park, C. S.; Thorndike, E. H.; Yang, F.

2007-08-01

We measure the decay constant fDs+ using the Ds+→ℓ+ν channel, where the ℓ+ designates either a μ+ or a τ+, when the τ+→π+ν¯. Using both measurements we find fDs+=274±13±7MeV. Combining with our previous determination of fD+, we compute the ratio fDs+/fD+=1.23±0.11±0.04. We compare with theoretical estimates.

Diagnostic value of fibronectin discriminant score for predicting liver fibrosis stages in chronic hepatitis C virus patients.

PubMed

Attallah, Abdelfattah M; Abdallah, Sanaa O; Attallah, Ahmed A; Omran, Mohamed M; Farid, Khaled; Nasif, Wesam A; Shiha, Gamal E; Abdel-Aziz, Abdel-Aziz F; Rasafy, Nancy; Shaker, Yehia M

2013-01-01

Several noninvasive predictive models were developed to substitute liver biopsy for fibrosis assessment. To evaluate the diagnostic value of fibronectin which reflect extracellular matrix metabolism and standard liver functions tests which reflect alterations in hepatic functions. Chronic hepatitis C (CHC) patients (n = 145) were evaluated using ROC curves and stepwise multivariate discriminant analysis (MDA) and was validated in 180 additional patients. Liver biochemical profile including transaminases, bilirubin, alkaline phosphatase, albumin, complete blood count were estimated. Fibronectin concentration was determined using monoclonal antibody and ELISA. A novel index named fibronectin discriminant score (FDS) based on fibronectin, APRI and albumin was developed. FDS produced areas under ROC curves (AUC) of 0.91 for significant fibrosis and 0.81 for advanced fibrosis. The FDS correctly classified 79% of the significant liver fibrosis patients (F2-F4) with 87% sensitivity and 75% specificity. The relative risk [odds ratio (OR)] of having significant liver fibrosis using the cut-off values determined by ROC curve analyses were 6.1 for fibronectin, 4.9 for APRI, and 4.2 for albumin. FDS predicted liver fibrosis with an OR of 16.8 for significant fibrosis and 8.6 for advanced fibrosis. The FDS had similar AUC and OR in the validation group to the estimation group without statistically significant difference. FDS predicted liver fibrosis with high degree of accuracy, potentially decreasing the number of liver biopsy required.

Family doctors' views of pharmaceutical sales representatives: assessment scale development.

PubMed

Kersnik, Janko; Klemenc-Ketis, Zalika; Petek-Ster, Marija; Tusek-Bunc, Ksenija; Poplas-Susic, Tonka; Kolsek, Marko

2011-08-01

The prescribing patterns depend on the physicians' attitudes and their subjective norms towards prescribing a particular drug, as well as on their personal experience with a particular drug. The physicians are affected by their interactions with pharmaceutical industry. The objectives were to develop a scale for assessment of pharmaceutical sales representatives (PSRs) by the family doctors (FDs) and to determine factors for their evaluation. Cross-sectional anonymous postal study. We included a random sample of 250 Slovenian FDs. Settings. Slovenian FDs' surgeries. The score of various items regarding FDs' assessment of PSRs on a 7-point Likert scale. We got 163 responses (65.2% response rate). The most important characteristic of PSRs, as rated by respondents on the scale from 1 to 7, was the fact that they did not mislead when presenting products' information. The second most important characteristic was the ability to provide objective information about the product. The first three most important characteristics, as rated by the respondents by themselves, were 'Shows good knowledge on the promoted subject', 'Provides objective product information' and 'Makes brief and exact visits'. Cronbach's alpha of the composite scale was 0.844. Factor analysis revealed three PSRs' factors: selling skills, communicating skills and sense of trustworthiness. FDs evaluate PSRs mainly by their managerial skills and trustworthiness. The scale proved to be a reliable tool for assessing PSRs by FDs.

The Mariner Venus Mercury flight data subsystem.

NASA Technical Reports Server (NTRS)

Whitehead, P. B.

1972-01-01

The flight data subsystem (FDS) discussed handles both the engineering and scientific measurements performed on the MVM'73. It formats the data into serial data streams, and sends it to the modulation/demodulation subsystem for transmission to earth or to the data storage subsystem for storage on a digital tape recorder. The FDS is controlled by serial digital words, called coded commands, received from the central computer sequencer of from the ground via the modulation/demodulation subsystem. The eight major blocks of the FDS are: power converter, timing and control, engineering data, memory, memory input/output and control, nonimaging data, imaging data, and data output. The FDS incorporates some 4000 components, weighs 17 kg, and uses 35 W of power. General data on the mission and spacecraft are given.

Experimental and Numerical Study on Effect of Sample Orientation on Auto-Ignition and Piloted Ignition of Poly(methyl methacrylate)

PubMed Central

Peng, Fei; Zhou, Xiao-Dong; Zhao, Kun; Wu, Zhi-Bo; Yang, Li-Zhong

2015-01-01

In this work, the effect of seven different sample orientations from 0° to 90° on pilot and non-pilot ignition of PMMA (poly(methyl methacrylate)) exposed to radiation has been studied with experimental and numerical methods. Some new and significant conclusions are drawn from the study, including a U-shape curve of ignition time and critical mass flux as sample angle increases for pilot ignition conditions. However, in auto-ignition, the ignition time and critical mass flux increases with sample angle α. Furthermore, a computational fluid dynamic model have been built based on the Fire Dynamics Simulator (FDS6) code to investigate the mechanisms controlling the dependence on sample orientation of the ignition of PMMA under external radiant heating. The results of theoretical analysis and modeling results indicate the decrease of total incident heat flux at sample surface plays the dominant role during the ignition processes of auto-ignition, but the volatiles gas flow has greater influence for piloted ignition conditions. PMID:28793421

Biodistribution and Radiation Dosimetry of the Enterobacteriaceae-Specific Imaging Probe [(18)F]Fluorodeoxysorbitol Determined by PET/CT in Healthy Human Volunteers.

PubMed

Zhu, Wenjia; Yao, Shaobo; Xing, Haiqun; Zhang, Hui; Tai, Yuan-Chuan; Zhang, Yingqiang; Liu, Yimin; Ma, Yanru; Wu, Chenxi; Wang, Hongkai; Li, Zibo; Wu, Zhanhong; Zhu, Zhaohui; Li, Fang; Huo, Li

2016-10-01

[(18)F]fluorodeoxysorbitol ([(18)F]FDS) is the first radiopharmaceutical specific for a category of bacteria and has the potential to specifically detect Enterobacteriaceae infections. The purpose of this study was to testify the safety and investigate the biodistribution and radiation dosimetry of [(18)F]FDS in healthy human bodies. Six healthy subjects were intravenously injected with 320-520 MBq [(18)F]FDS. On each subject, 21 whole-body emission scans and a brain scan were conducted at settled time points within the next 4 h. Residence time for each source organ was determined by multi-exponential regression. Absorbed doses for target organs and effective dose were calculated via OLINDA/EXM. No adverse events due to [(18)F]FDS injection were observed in the study. The tracer was cleared rapidly from the blood pool through the urinary system. A small portion was cleared into the gut through the hepatobiliary system. The effective dose (ED) was estimated to be 0.021 ± 0.001 mSv/MBq. The organ receiving the highest absorbed dose was the urinary bladder wall (0.25 ± 0.03 mSv/MBq). [(18)F]FDS is safe and well tolerated. The effective dose was comparable to that of other F-18 labeled radiotracers. [(18)F]FDS is suitable for human use from a radiation dosimetry perspective.

Parametric Characterization of Flow Inside Cererbal Aneurysms Treated with Flow-Diverting Stents

NASA Astrophysics Data System (ADS)

Barbour, Michael; Levitt, Michael; Geindreau, Christian; Johnson, Luke; Chivukula, Keshav; Aliseda, Alberto

2017-11-01

Cerebral aneurysms are often treated with a flow-diverting stent (FDS) to reduce blood flow into the aneurysm sac, promoting the development of a stable thrombus. Successful treatment is highly dependent on the degree of flow reduction and the altered hemodynamics inside the aneurysm sac following treatment. Establishing a causal connection between hemodynamic metrics of FDS-treated CAs and long-term clinical outcomes requires a rigorous parametric characterization of this flow environment. We use 3D particle image velocimetry (PIV) to measure the flow inside idealized aneurysm models treated with FDS. Physiologically realistic Reynolds numbers and increasing levels of parent vessel curvature are analyzed to understand the effect of inertia on flow development. The flow velocity into the aneurysm and the topology of the flow inside the sac is shown to be highly dependent on parent vessel Dean number (De). The role of flow pulsatility is then added to the study via time-dependent waveforms. Velocity measurements at 2 values of parent vessel Womersley number (Wo) allow us to parameterize flow inside of CAs treated with FDS as a function of De, Re and Wo, improving the fundamental understanding of how FDS alter CA hemodynamics and aiding in the development of new treatments.

A Deep Look at the Fornax Cluster

NASA Astrophysics Data System (ADS)

Kohler, Susanna

2016-04-01

Traditionally, dense cluster centers are cannibalistic environments, with larger galaxies stripping stars from smaller interlopers in minor mergers and dynamical harassment. A recent survey of the Fornax cluster, one example of such an environment, reveals how this cluster may have been built.Clues in HalosContext for the southern constellation Fornax (the furnace). The Fornax cluster is marked with a red circle. [ESO, IAU and Sky Telescope]Deep surveys of dense cluster environments are necessary because the imprint of mass assembly is hidden in galactic halos, the faint outer regions of galaxies. Deep observations can reveal answers to questions about how the galaxies in these extreme environments formed and evolved for instance, did the majority of the galaxies stars form in situ, or were they accreted from interactions with other galaxies?The Fornax Deep Survey (FDS) is just such a campaign. FDS uses the European Southern Observatorys VLT Survey Telescope to obtain deep photometry of the entire 26 square degrees of the Fornax cluster, a spectacular galaxy cluster located 65 million light-years away.Central ObservationsThe FDS team plans to release the full results from the survey soon. For now, in an initial study led by Enrichetta Iodice (INAFs Astronomical Observatory of Capodimonte, Italy), the team presents their first findings from the two square degrees around NGC 1399, a supergiant elliptical galaxy in the cluster center.The two main results from this study are:The discovery of a faint stellar bridge between NGC 1399 and a nearby galaxy, NGC 1387.The characterization of NGC 1399s light profile, which shows that the galaxy consists of two main components separated by a strong break. The bright central galaxy is likely composed of stars that formed in situ, whereas the exponential outer component is a stellar halo composed of stars likely captured from accretion events.What do these points tell us about the history of the center of the Fornax cluster? These observations are indications that the Fornax cluster was built up by mergers and accretion events.A Violent PastThe light profile the authors found is consistent with those of simulated galaxies whose halos were formed through the multiple accretion of progenitors. This suggests that the stellar halo of NGC 1399 has been through a major merging event.This enlarged view of NGC 1399 and 1387 in the g band (top) and gi band (bottom) gives a better view of the faint stellar stream connecting the two galaxies. North is up and east is left. [Iodice et al. 2016]The faint stellar bridge is likely a sign of an ongoing interaction between NGC 1399 and NGC 1387, in which NGC 1387s outer envelope on its east side is being stripped away. But besides this indication, there is little evidence for recent merger activity, which would usually produce a significant number of luminous stellar streams and tidal tails.The authors argue that this means that any major mergers in the Fornax cluster center probably happened in an early formation epoch. The cluster is now in a more dynamically evolved stage, in which most of the gravitational interactions between galaxies have already taken place.Follow-up kinematics studies will be crucial to further interpreting these photometric observations from the center of the Fornax cluster. In the meantime, keep an eye out for future results from FDS!CitationE. Iodice et al 2016 ApJ 820 42. doi:10.3847/0004-637X/820/1/42

Design of analytical failure detection using secondary observers

NASA Technical Reports Server (NTRS)

Sisar, M.

1982-01-01

The problem of designing analytical failure-detection systems (FDS) for sensors and actuators, using observers, is addressed. The use of observers in FDS is related to the examination of the n-dimensional observer error vector which carries the necessary information on possible failures. The problem is that in practical systems, in which only some of the components of the state vector are measured, one has access only to the m-dimensional observer-output error vector, with m or = to n. In order to cope with these cases, a secondary observer is synthesized to reconstruct the entire observer-error vector from the observer output error vector. This approach leads toward the design of highly sensitive and reliable FDS, with the possibility of obtaining a unique fingerprint for every possible failure. In order to keep the observer's (or Kalman filter) false-alarm rate under a certain specified value, it is necessary to have an acceptable matching between the observer (or Kalman filter) models and the system parameters. A previously developed adaptive observer algorithm is used to maintain the desired system-observer model matching, despite initial mismatching or system parameter variations. Conditions for convergence for the adaptive process are obtained, leading to a simple adaptive law (algorithm) with the possibility of an a priori choice of fixed adaptive gains. Simulation results show good tracking performance with small observer output errors, while accurate and fast parameter identification, in both deterministic and stochastic cases, is obtained.

Repositioning forelimb superficialis muscles: tendon attachment and muscle activity enable active relocation of functional myofibers.

PubMed

Huang, Alice H; Riordan, Timothy J; Wang, Lingyan; Eyal, Shai; Zelzer, Elazar; Brigande, John V; Schweitzer, Ronen

2013-09-16

The muscles that govern hand motion are composed of extrinsic muscles that reside within the forearm and intrinsic muscles that reside within the hand. We find that the extrinsic muscles of the flexor digitorum superficialis (FDS) first differentiate as intrinsic muscles within the hand and then relocate as myofibers to their final position in the arm. This remarkable translocation of differentiated myofibers across a joint is dependent on muscle contraction and muscle-tendon attachment. Interestingly, the intrinsic flexor digitorum brevis (FDB) muscles of the foot are identical to the FDS in tendon pattern and delayed developmental timing but undergo limited muscle translocation, providing strong support for evolutionary homology between the FDS and FDB muscles. We propose that the intrinsic FDB pattern represents the original tetrapod limb and that translocation of the muscles to form the FDS is a mammalian evolutionary addition. Copyright © 2013 Elsevier Inc. All rights reserved.

Re-positioning forelimb superficialis muscles: tendon attachment and muscle activity enable active relocation of functional myofibers

PubMed Central

Huang, Alice H.; Riordan, Timothy J.; Wang, Lingyan; Eyal, Shai; Zelzer, Elazar; Brigande, John V.; Schweitzer, Ronen

2013-01-01

Summary The muscles that govern hand motion are composed of extrinsic muscles that reside within the forearm and intrinsic muscles that reside within the hand. We find that the extrinsic muscles of the flexor digitorum superficialis (FDS) first differentiate as intrinsic muscles within the hand and then relocate as myofibers to their final position in the arm. This unique translocation of differentiated myofibers across a joint is dependent on muscle contraction and muscle-tendon attachment. Interestingly, the intrinsic flexor digitorum brevis (FDB) muscles of the foot are identical to the FDS in tendon pattern and delayed developmental timing, but undergo limited muscle translocation, providing strong support for evolutionary homology between the FDS and FDB muscles. We propose that the intrinsic FDB pattern represents the original tetrapod limb and translocation of the muscles to form the FDS is a mammalian evolutionary addition. PMID:24044893

Analysis of the Influence of Construction Insulation Systems on Public Safety in China

PubMed Central

Zhang, Guowei; Zhu, Guoqing; Zhao, Guoxiang

2016-01-01

With the Government of China’s proposed Energy Efficiency Regulations (GB40411-2007), the implementation of external insulation systems will be mandatory in China. The frequent external insulation system fires cause huge numbers of casualties and extensive property damage and have rapidly become a new hot issue in construction evacuation safety in China. This study attempts to reconstruct an actual fire scene and propose a quantitative risk assessment method for upward insulation system fires using thermal analysis tests and large eddy simulations (using the Fire Dynamics Simulator (FDS) software). Firstly, the pyrolysis and combustion characteristics of Extruded polystyrene board (XPS panel), such as ignition temperature, combustion heat, limiting oxygen index, thermogravimetric analysis and thermal radiation analysis were studied experimentally. Based on these experimental data, large eddy simulation was then applied to reconstruct insulation system fires. The results show that upward insulation system fires could be accurately reconstructed by using thermal analysis test and large eddy simulation. The spread of insulation material system fires in the vertical direction is faster than that in the horizontal direction. Moreover, we also find that there is a possibility of flashover in enclosures caused by insulation system fires as the smoke temperature exceeds 600 °C. The simulation methods and experimental results obtained in this paper could provide valuable references for fire evacuation, hazard assessment and fire resistant construction design studies. PMID:27589774

Analysis of the Influence of Construction Insulation Systems on Public Safety in China.

PubMed

Zhang, Guowei; Zhu, Guoqing; Zhao, Guoxiang

2016-08-30

With the Government of China's proposed Energy Efficiency Regulations (GB40411-2007), the implementation of external insulation systems will be mandatory in China. The frequent external insulation system fires cause huge numbers of casualties and extensive property damage and have rapidly become a new hot issue in construction evacuation safety in China. This study attempts to reconstruct an actual fire scene and propose a quantitative risk assessment method for upward insulation system fires using thermal analysis tests and large eddy simulations (using the Fire Dynamics Simulator (FDS) software). Firstly, the pyrolysis and combustion characteristics of Extruded polystyrene board (XPS panel), such as ignition temperature, combustion heat, limiting oxygen index, thermogravimetric analysis and thermal radiation analysis were studied experimentally. Based on these experimental data, large eddy simulation was then applied to reconstruct insulation system fires. The results show that upward insulation system fires could be accurately reconstructed by using thermal analysis test and large eddy simulation. The spread of insulation material system fires in the vertical direction is faster than that in the horizontal direction. Moreover, we also find that there is a possibility of flashover in enclosures caused by insulation system fires as the smoke temperature exceeds 600 °C. The simulation methods and experimental results obtained in this paper could provide valuable references for fire evacuation, hazard assessment and fire resistant construction design studies.

Quality improvement competency gaps in primary care in Albanian, polish and slovenian contexts: a study protocol.

PubMed

Czabanowska, Katarzyna; Burazeri, Genc; Klemenc-Ketis, Zalika; Kijowska, Violetta; Tomasik, Tomasz; Brand, Helmut

2012-12-01

Nowadays, general practitioners (GPs) and family doctors (FDs) face increasing demands, as a consequence of complex patients' expectations, developments in science and technology, and limitations within healthcare systems which can result in competency gaps. Therefore, there is a need to identify which competencies in quality improvement (QI) are most important for GPs and FDs to possess in order to meet the demands of contemporary health care practice. To date, however, little information is available on the self-assessment of competencies related to QI among GPs and FDs. To deal with these issues, a project on QI in continuous medical education was launched in 2011. The project aims to broaden the GPs'/ FDs' continuous education offer, its quality and attractiveness, as well as provide them with opportunities for vocational advancement and enable the development of common, European frame of reference for GPs'/FDs' occupational competencies. The third work package of the project consists of the validation research of the questionnaire developed on the basis of the competency framework in QI for GPs/FDs in Europe. A cross-sectional study will be carried out using the self-assessment QI questionnaire which was originally developed in English and subsequently it was cross-culturally adapted in Slovenian, Albanian and Polish settings by use of a pilot study on a conveniently selected group of FDs/GPs (N=10) in each participating country. The final version of the questionnaire will be administered to large samples in each country involved in the survey. Two weeks after the first administration of the questionnaire, a second round, with the same procedure and including the same group of respondents, will follow. Psychometric tests will be conducted including internal consistency (after the initial and subsequent application of the instrument) and stability over time (two-week test-retest reliability). This self-assessment study will demonstrate the complex environment in which general practice/family medicine operates and, eventually, this gap analysis will set out strategically important areas for collaborative efforts related to QI in primary care. The authors consider that the study should be extended to other European countries to help identify most required competencies that GPs/FDs should possess in Europe and thus stir system and educational debate around QI curricula and training for primary care in Europe.

Path to Impact for Autonomous Field Deployable Chemical Sensors: A Case Study of in Situ Nitrite Sensors.

PubMed

Schierenbeck, Tim M; Smith, Matthew C

2017-05-02

Natural freshwater systems have been severely affected by excess loading of macronutrients (e.g., nitrogen and phosphorus) from fertilizers, fossil fuels, and human and livestock waste. In the USA, impacts to drinking water quality, biogeochemical cycles, and aquatic ecosystems are estimated to cost US$210 billion annually. Field-deployable nutrient sensors (FDS) offer potential to support research and resource management efforts by acquiring higher resolution data than are currently supported by expensive conventional sampling methods. Following nearly 40 years of research and development, FDS instruments are now starting to penetrate commercial markets. However, instrument uncertainty factors (high cost, reliability, accuracy, and precision) are key drivers impeding the uptake of FDS by the majority of users. Using nitrite sensors as a case study, we review the trends, opportunities, and challenges in producing and implementing FDS from a perspective of innovation and impact. We characterize the user community and consumer needs, identify trends in research approaches, tabulate state-of-the-art examples and specifications, and discuss data life cycle considerations. With further development of FDS through prototyping and testing in real-world applications, these tools can deliver information for protecting and restoring natural waters, enhancing process control for industrial operations and water treatment, and providing novel research insights.

Paediatric interventional cardiology: flat detector versus image intensifier using a test object

NASA Astrophysics Data System (ADS)

Vano, E.; Ubeda, C.; Martinez, L. C.; Leyton, F.; Miranda, P.

2010-12-01

Entrance surface air kerma (ESAK) values and image quality parameters were measured and compared for two biplane angiography x-ray systems dedicated to paediatric interventional cardiology, one equipped with image intensifiers (II) and the other one with dynamic flat detectors (FDs). Polymethyl methacrylate phantoms of different thicknesses, ranging from 8 to 16 cm, and a Leeds TOR 18-FG test object were used. The parameters of the image quality evaluated were noise, signal-difference-to-noise ratio (SdNR), high contrast spatial resolution (HCSR) and three figures of merit combining entrance doses and signal-to-noise ratios or HCSR. The comparisons showed a better behaviour of the II-based system in the low contrast region over the whole interval of thicknesses. The FD-based system showed a better performance in HCSR. The FD system evaluated would need around two times more dose than the II system evaluated to reach a given value of SdNR; moreover, a better spatial resolution was measured (and perceived in conventional monitors) for the system equipped with flat detectors. According to the results of this paper, the use of dynamic FD systems does not lead to an automatic reduction in ESAK or to an automatic improvement in image quality by comparison with II systems. Any improvement also depends on the setting of the x-ray systems and it should still be possible to refine these settings for some of the dynamic FDs used in paediatric cardiology.

Symptoms of Fern Distortion Syndrome Resulting from Inoculation with Opportunistic Endophytic Fluorescent Pseudomonas spp.

PubMed Central

Kloepper, Joseph W.; McInroy, John A.; Liu, Ke; Hu, Chia-Hui

2013-01-01

Background Fern Distortion Syndrome (FDS) is a serious disease of Leatherleaf fern (Rumohra adiantiformis). The main symptom of FDS is distortion of fronds, making them unmarketable. Additional symptoms include stunting, irregular sporulation, decreased rhizome diameter, and internal discoloration of rhizomes. We previously reported an association of symptoms with increased endophytic rhizome populations of fluorescent pseudomonads (FPs). The aim of the current study was to determine if FPs from ferns in Costa Rica with typical FDS symptoms would recreate symptoms of FDS. Methodology and Findings Greenhouse tests were conducted over a 29-month period. Micro-propagated ferns derived from tissue culture were first grown one year to produce rhizomes. Then, using an 8×9 randomized complete block experimental design, 8 replicate rhizomes were inoculated by dipping into 9 different treatments before planting. Treatments included water without bacteria (control), and four different groups of FPs, each at a two concentrations. The four groups of FPs included one group from healthy ferns without symptoms (another control treatment), two groups isolated from inside rhizomes of symptomatic ferns, and one group isolated from inside roots of symptomatic ferns. Symptoms were assessed 12 and 17 months later, and populations of FPs inside newly formed rhizomes were determined after 17 months. Results showed that inoculation with mixtures of FPs from ferns with FDS symptoms, but not from healthy ferns, recreated the primary symptom of frond deformities and also the secondary symptoms of irregular sporulation, decreased rhizome diameter, and internal discoloration of rhizomes. Conclusions These results suggest a model of causation of FDS in which symptoms result from latent infections by multiple species of opportunistic endophytic bacteria containing virulence genes that are expressed when populations inside the plant reach a minimum level. PMID:23516499

Better control with less effort: The advantage of using focused-breathing strategy over focused-distraction strategy on thought suppression.

PubMed

Ju, Yu-Jeng; Lien, Yunn-Wen

2016-02-01

It has been suggested that unwanted thoughts usually intrude during mind wandering due to a shortage of mental resources. However, strategies for suppressing such thoughts have never been examined from a mind wandering perspective. Here, we compare the effectiveness of two types of attention distraction strategies that either redirect users' attention to their own breathing (focused-breathing strategy, FBS) or to a mental image (focused-distraction strategy, FDS) as related to working memory capacities. Eighty-two undergraduates were randomly assigned into a FBS or FDS group. They completed a concentration task and a thought suppression task, in which mind wandering and thought intrusions were each measured. Our results support the hypothesis that mind wandering is positively correlated to thought intrusions and shows that FBS is more effective than FDS in reducing mind wandering and thought intrusions. Moreover, in contrast to FDS, the effect of FBS is independent of users' mental resources. Copyright © 2015 Elsevier Inc. All rights reserved.

Influences of exit and stair conditions on human evacuation in a dormitory

NASA Astrophysics Data System (ADS)

Lei, Wenjun; Li, Angui; Gao, Ran; Wang, Xiaowei

2012-12-01

Evacuation processes of students are investigated by experiment and simulation. The experiment is performed for students evacuating from a dormitory with an exit and stairs. FDS+Evac is proposed to simulate the exit and stair dynamics of occupant evacuation. Concerning the exit and stair widths, we put forward some useful standpoints. Good agreement is achieved between the predicted results and experimental results. With the increase of exit width, a significant stratification phenomenon will be found in flow rate. Stratification phenomenon is that two different stable flow rates will emerge during the evacuation. And the flow rate curve looks like a ladder. The larger the exit width, the earlier the stratification phenomenon appears. When exit width is more than 2.0 m, the flow rate of each exit width is divided into two stable stages, and the evacuation times show almost no change. The judgment that the existence of stairs causes flow stratification is reasonable. By changing the width of the stairs, we proved that judgment. The smaller the width of BC, the earlier the stratification appears. We found that scenario 5 is the most adverse circumstance. Those results are helpful in performance-based design of buildings.

Monochromatic multicomponent fluorescence sedimentation velocity for the study of high-affinity protein interactions

PubMed Central

Zhao, Huaying; Fu, Yan; Glasser, Carla; Andrade Alba, Eric J; Mayer, Mark L; Patterson, George; Schuck, Peter

2016-01-01

The dynamic assembly of multi-protein complexes underlies fundamental processes in cell biology. A mechanistic understanding of assemblies requires accurate measurement of their stoichiometry, affinity and cooperativity, and frequently consideration of multiple co-existing complexes. Sedimentation velocity analytical ultracentrifugation equipped with fluorescence detection (FDS-SV) allows the characterization of protein complexes free in solution with high size resolution, at concentrations in the nanomolar and picomolar range. Here, we extend the capabilities of FDS-SV with a single excitation wavelength from single-component to multi-component detection using photoswitchable fluorescent proteins (psFPs). We exploit their characteristic quantum yield of photo-switching to imprint spatio-temporal modulations onto the sedimentation signal that reveal different psFP-tagged protein components in the mixture. This novel approach facilitates studies of heterogeneous multi-protein complexes at orders of magnitude lower concentrations and for higher-affinity systems than previously possible. Using this technique we studied high-affinity interactions between the amino-terminal domains of GluA2 and GluA3 AMPA receptors. DOI: http://dx.doi.org/10.7554/eLife.17812.001 PMID:27436096

Flight design system level C requirements. Solid rocket booster and external tank impact prediction processors. [space transportation system

NASA Technical Reports Server (NTRS)

Seale, R. H.

1979-01-01

The prediction of the SRB and ET impact areas requires six separate processors. The SRB impact prediction processor computes the impact areas and related trajectory data for each SRB element. Output from this processor is stored on a secure file accessible by the SRB impact plot processor which generates the required plots. Similarly the ET RTLS impact prediction processor and the ET RTLS impact plot processor generates the ET impact footprints for return-to-launch-site (RTLS) profiles. The ET nominal/AOA/ATO impact prediction processor and the ET nominal/AOA/ATO impact plot processor generate the ET impact footprints for non-RTLS profiles. The SRB and ET impact processors compute the size and shape of the impact footprints by tabular lookup in a stored footprint dispersion data base. The location of each footprint is determined by simulating a reference trajectory and computing the reference impact point location. To insure consistency among all flight design system (FDS) users, much input required by these processors will be obtained from the FDS master data base.

In vivo transport of three radioactive [18F]-fluorinated deoxysucrose analogs by the maize sucrose transporter ZmSUT1.

PubMed

Tran, Thu M; Hampton, Carissa S; Brossard, Tom W; Harmata, Michael; Robertson, J David; Jurisson, Silvia S; Braun, David M

2017-06-01

Sucrose transporter (SUT) proteins translocate sucrose across cell membranes; however, mechanistic aspects of sucrose binding by SUTs are not well resolved. Specific hydroxyl groups in sucrose participate in hydrogen bonding with SUT proteins. We previously reported that substituting a radioactive fluorine-18 [ 18 F] at the C-6' position within the fructosyl moiety of sucrose did not affect sucrose transport by the maize (Zea mays) ZmSUT1 protein. To determine how 18 F substitution of hydroxyl groups at two other positions within sucrose, the C-1' in the fructosyl moiety or the C-6 in the glucosyl moiety, impact sucrose transport, we synthesized 1'-[F 18 ]fluoro-1'-deoxysucrose and 6-[F 18 ]fluoro-6-deoxysucrose ([ 18 F]FDS) analogs. Each [ 18 F]FDS derivative was independently introduced into wild-type or sut1 mutant plants, which are defective in sucrose phloem loading. All three (1'-, 6'-, and 6-) [ 18 F]FDS derivatives were efficiently and equally translocated, similarly to carbon-14 [ 14 C]-labeled sucrose. Hence, individually replacing the hydroxyl groups at these positions within sucrose does not interfere with substrate recognition, binding, or membrane transport processes, and hydroxyl groups at these three positions are not essential for hydrogen bonding between sucrose and ZmSUT1. [ 18 F]FDS imaging afforded several advantages compared to [ 14 C]-sucrose detection. We calculated that 1'-[ 18 F]FDS was transported at approximately a rate of 0.90 ± 0.15 m.h-1 in wild-type leaves, and at 0.68 ± 0.25 m.h-1 in sut1 mutant leaves. Collectively, our data indicated that [ 18 F]FDS analogs are valuable tools to probe sucrose-SUT interactions and to monitor sucrose transport in plants. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

The flare origin of Forbush decreases not associated with solar flares on the visible hemisphere of the Sun

NASA Technical Reports Server (NTRS)

Iucci, N.; Parisi, M.; Signorini, C.; Storini, M.; Villoresi, G.

1985-01-01

Investigations have shown that Forbush decreases (Fds) are produced by the propagation into the interplanetary space of a strong perturbation originating from a solar flare (Sf) accompanied by Type IV radioemission. As the front of the perturbation propagates into the interplanetary space, the region in which the galactic cosmic rays are modulated (Fd-modulated region) rotates westward with the Sun and is generally included between two boundary streams; therefore the Fds not associated with observed type IV Sfs (N.Ass.Fds) are likely to be produced by type IV Sfs occurred on the Sun's backside: these vents can be observed when the Earth crosses the corotating Western boundary of the modulated region.

The flare origin of Forbush decreases not associated with solar flares on the visible hemisphere of the Sun

NASA Astrophysics Data System (ADS)

Iucci, N.; Parisi, M.; Signorini, C.; Storini, M.; Villoresi, G.

1985-08-01

Investigations have shown that Forbush decreases (Fds) are produced by the propagation into the interplanetary space of a strong perturbation originating from a solar flare (Sf) accompanied by Type IV radioemission. As the front of the perturbation propagates into the interplanetary space, the region in which the galactic cosmic rays are modulated (Fd-modulated region) rotates westward with the Sun and is generally included between two boundary streams; therefore the Fds not associated with observed type IV Sfs (N.Ass.Fds) are likely to be produced by type IV Sfs occurred on the Sun's backside: these vents can be observed when the Earth crosses the corotating Western boundary of the modulated region.

A Biomechanical Simulation of the Effect of the Extrinsic Flexor Muscles on Finger Joint Flexion

DTIC Science & Technology

2001-10-25

vol. 44, pp. 493-504, 1997. [8] A.B. Leger and T.E. Milner, “The effect of eccentric exercise on intrinsic and reflex stiffness in the human hand...line of action of the tendons and the effective moment arms. After a certain point, the FDP tendon became slack, while the FDS tendon remained...link chain with three revolute joints and four links was created to model the index finger. The tendons from the extrinsic flexor muscles were

A dose-response evaluation of freeze-dried strawberries independent of fiber content on metabolic indices in abdominally obese individuals with insulin resistance in a randomized, single-blinded, diet-controlled crossover trial.

PubMed

Park, Eunyoung; Edirisinghe, Indika; Wei, Hequn; Vijayakumar, Lakshmi Prabha; Banaszewski, Katarzyna; Cappozzo, Jack C; Burton-Freeman, Britt

2016-05-01

This study evaluated the dose-response relationship of strawberries, an anthocyanin-rich fruit, on postprandial glucose and insulin concentrations in individuals with insulin resistance (IR), including changes in plasma anthocyanins, markers of oxidative stress, and inflammation. In a randomized controlled, four-arm, dose-response, crossover trial, 21 adults with IR consumed a high-carbohydrate, high-fat meal with one of four beverages containing 0 g freeze-dried whole strawberry powder (0g FDS, control), 10, 20, or 40 g FDS, controlled for fiber. Blood was collected at 0 min and at 30 min intervals postmeal until 2 h, then hourly until 6 h. Postmeal insulin concentrations (6 h) were significantly reduced after the 40-g FDS beverage compared to other beverages (p < 0.05). Postmeal 6 h glucose concentrations were not different, although mean insulin:glucose ratio was significantly different among beverages (p < 0.05). Pelargonidin-glucuronide was inversely associated with mean insulin concentrations after the 20 and 40 g FDS (p < 0.05). Oxidized low-density lipoprotein was reduced after 20 g FDS (p < 0.05) and IL-6 was not different among treatments. Strawberry intake reduced the insulin demand to manage postmeal glucose in obese individuals with IR, which was related to plasma anthocyanin/pelargonidin concentrations. The data support a role of strawberries in improving insulin sensitivity in people with IR. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Burnout in European family doctors: the EGPRN study.

PubMed

Soler, Jean Karl; Yaman, Hakan; Esteva, Magdalena; Dobbs, Frank; Asenova, Radost Spiridonova; Katic, Milica; Ozvacic, Zlata; Desgranges, Jean Pierre; Moreau, Alain; Lionis, Christos; Kotányi, Péter; Carelli, Francesco; Nowak, Pawel R; de Aguiar Sá Azeredo, Zaida; Marklund, Eva; Churchill, Dick; Ungan, Mehmet

2008-08-01

The aim of this study was to determine the prevalence of burnout, and of associated factors, amongst family doctors (FDs) in European countries. Methodology. A cross-sectional survey of FDs was conducted using a custom-designed and validated questionnaire which incorporated the Maslach Burnout Inventory Human Services Survey (MBI-HSS) as well as questions about demographic factors, working experience, health, lifestyle and job satisfaction. MBI-HSS scores were analysed in the three dimensions of emotional exhaustion (EE), depersonalization (DP) and personal accomplishment (PA). Almost 3500 questionnaires were distributed in 12 European countries, and 1393 were returned to give a response rate of 41%. In terms of burnout, 43% of respondents scored high for EE burnout, 35% for DP and 32% for PA, with 12% scoring high burnout in all three dimensions. Just over one-third of doctors did not score high for burnout in any dimension. High burnout was found to be strongly associated with several of the variables under study, especially those relative to respondents' country of residence and European region, job satisfaction, intention to change job, sick leave utilization, the (ab)use of alcohol, tobacco and psychotropic medication, younger age and male sex. Burnout seems to be a common problem in FDs across Europe and is associated with personal and workload indicators, and especially job satisfaction, intention to change job and the (ab)use of alcohol, tobacco and medication. The study questionnaire appears to be a valid tool to measure burnout in FDs. Recommendations for employment conditions of FDs and future research are made, and suggestions for improving the instrument are listed.

Circulating filarial antigen in the hydrocele fluid from individuals living in a bancroftian filariasis area - Recife, Brazil: detected by the monoclonal antibody Og4C3-assay.

PubMed

Rocha, Abraham; Lima, Guilherme; Medeiros, Zulma; Aguiar-Santos, Ana; Alves, Sandra; Montarroyos, Ulisses; Oliveira, Paula; Béliz, Fátima; Netto, Maria José; Furtado, André

2004-02-01

The purpose of this study was to examine the circulating filarial antigen (CFA) detected by the monoclonal antibody (mAb) Og4C3-ELISA in paired samples of serum and hydrocele fluid from 104 men with hydrocele, living in an endemic area of Wuchereria bancrofti. Nocturnal blood specimens were filtered and examined for microfilariae (MF) and ultrasound was used in order to identify the presence of adult worms (the filaria dance sign - FDS) in the lymphatic vessels of the scrotal area. Four groups were selected according to their parasitological status: group I - 71 MF- and FDS-; group II - 21 MF+ and FDS+; group III - 10 MF- and FDS+ and group IV- 2 MF+ and FDS-. CFA was identified simultaneously (fluid and serum) in 11 (15.5%), 21 (100%), 3 (30%), and 1 (50%) in groups I, II, III, and IV, respectively. In despite of high CFA+ level (antigen Og4C3) units/ml, the Geometrical Mean (GM) = 2696) in the sera of these 36/104 paired samples, when compared to the hydrocele fluid, (GM = 1079), showed a very good correlation between the CFA level in the serum and CFA level in the fluid (r = 0.731). CFA level in the serum of the 23 microfilaremics (groups II and IV) was extremely high (GM = 4189) and was correlated with MF density (r = 0.442). These findings report for the first time the potential alternative use of the hydrocele fluid to investigate CFA using the mAb Og4C3-ELISA.

Man-machine interface analysis of the flight design system

NASA Technical Reports Server (NTRS)

Ramsey, H. R.; Atwood, M. E.; Willoughby, J. K.

1978-01-01

The objective of the current effort was to perform a broad analysis of the human factors issues involved in the design of the Flight Design System (FDS). The analysis was intended to include characteristics of the system itself, such as: (1) basic structure and functional capabilities of FDS; (2) user backgrounds, capabilities, and possible modes of use; (3) FDS interactive dialogue, problem solving aids; (4) system data management capabilities; and to include, as well, such system related matters as: (1) flight design team structure; (2) roles of technicians; (3) user training; and (4) methods of evaluating system performance. Wherever possible, specific recommendations are made. In other cases, the issues which seem most important are identified. In some cases, additional analyses or experiments which might provide resolution are suggested.

Simplified Design Method for Tension Fasteners

NASA Astrophysics Data System (ADS)

Olmstead, Jim; Barker, Paul; Vandersluis, Jonathan

2012-07-01

Tension fastened joints design has traditionally been an iterative tradeoff between separation and strength requirements. This paper presents equations for the maximum external load that a fastened joint can support and the optimal preload to achieve this load. The equations, based on linear joint theory, account for separation and strength safety factors and variations in joint geometry, materials, preload, load-plane factor and thermal loading. The strength-normalized versions of the equations are applicable to any fastener and can be plotted to create a "Fastener Design Space", FDS. Any combination of preload and tension that falls within the FDS represents a safe joint design. The equation for the FDS apex represents the optimal preload and load capacity of a set of joints. The method can be used for preliminary design or to evaluate multiple pre-existing joints.

Gas Evolution Dynamics in Godunov-Type Schemes and Analysis of Numerical Shock Instability

NASA Technical Reports Server (NTRS)

Xu, Kun

1999-01-01

In this paper we are going to study the gas evolution dynamics of the exact and approximate Riemann solvers, e.g., the Flux Vector Splitting (FVS) and the Flux Difference Splitting (FDS) schemes. Since the FVS scheme and the Kinetic Flux Vector Splitting (KFVS) scheme have the same physical mechanism and similar flux function, based on the analysis of the discretized KFVS scheme the weakness and advantage of the FVS scheme are closely observed. The subtle dissipative mechanism of the Godunov method in the 2D case is also analyzed, and the physical reason for shock instability, i.e., carbuncle phenomena and odd-even decoupling, is presented.

Tissue Engineering Initiative

DTIC Science & Technology

2002-08-01

evaluate functionality, the FDP/SIS and FDS were independently pulled to determine the degree of distal interphalangeal (DIP) joint motion contributed by...each. In three digits the distal phalanx moved similarly whether pulling on the FDP/SIS or the FDS tendon. This suggests some scarring/adhesions between... pulled to determine the degree of distal interphalangeal (DIP) joint motion contributed by each. In three digits the distal phalanx moved similarly

Hybrid Upwind Splitting (HUS) by a Field-by-Field Decomposition

NASA Technical Reports Server (NTRS)

Coquel, Frederic; Liou, Meng-Sing

1995-01-01

We introduce and develop a new approach for upwind biasing: the hybrid upwind splitting (HUS) method. This original procedure is based on a suitable hybridization of current prominent flux vector splitting (FVS) and flux difference splitting (FDS) methods. The HUS method is designed to naturally combine the respective strengths of the above methods while excluding their main deficiencies. Specifically, the HUS strategy yields a family of upwind methods that exhibit the robustness of FVS schemes in the capture of nonlinear waves and the accuracy of some FDS schemes in the resolution of linear waves. We give a detailed construction of the HUS methods following a general and systematic procedure directly performed at the basic level of the field by field (i.e. waves) decomposition involved in FDS methods. For such a given decomposition, each field is endowed either with FVS or FDS numerical fluxes, depending on the nonlinear nature of the field under consideration. Such a design principle is made possible thanks to the introduction of a convenient formalism that provides us with a unified framework for upwind methods. The HUS methods we propose bring significant improvements over current methods in terms of accuracy and robustness. They yield entropy-satisfying approximate solutions as they are strongly supported in numerical experiments. Field by field hybrid numerical fluxes also achieve fairly simple and explicit expressions and hence require a computational effort between that of the FVS and FDS. Several numerical experiments ranging from stiff 1D shock-tube to high speed viscous flows problems are displayed, intending to illustrate the benefits of the present approach. We assess in particular the relevance of our HUS schemes to viscous flow calculations.

Imaging Enterobacteriaceae infection in vivo with 18F-fluorodeoxysorbitol positron emission tomography

PubMed Central

Weinstein, Edward A.; Ordonez, Alvaro A.; DeMarco, Vincent P.; Murawski, Allison M.; Pokkali, Supriya; MacDonald, Elizabeth M.; Klunk, Mariah; Mease, Ronnie C.; Pomper, Martin G.; Jain, Sanjay K.

2015-01-01

The Enterobacteriaceae are a family of rod-shaped Gram-negative bacteria that normally inhabit the gastrointestinal tract and are the most common cause of Gram-negative bacterial infections in humans. In addition to causing serious multidrug-resistant, hospital-acquired infections, a number of Enterobacteriaceae species are also recognized as biothreat pathogens. As a consequence, new tools are urgently needed to specifically identify and localize infections due to Enterobacteriaceae and to monitor antimicrobial efficacy. In this report, we used commercially available 2-[18F]-fluorodeoxyglucose (18F-FDG) to produce 2-[18F]-fluorodeoxysorbitol (18F-FDS), a radioactive probe for Enterobacteriaceae, in 30 min. 18F-FDS selectively accumulated in Enterobacteriaceae, but not in Gram-positive bacteria or healthy mammalian or cancer cells in vitro. In a murine myositis model, 18F-FDS positron emission tomography (PET) rapidly differentiated true infection from sterile inflammation with a limit of detection of 6.2 ± 0.2 log10 colony-forming units (CFU) for Escherichia coli. Our findings were extended to models of mixed Gram-positive and Gram-negative thigh co-infections, brain infection, Klebsiella pneumonia, and mice undergoing immunosuppressive chemotherapy. This technique rapidly and specifically localized infections due to Enterobacteriaceae, providing a three-dimensional holistic view within the animal. Last, 18F-FDS PET monitored the efficacy of antimicrobial treatment, demonstrating a PET signal proportionate to the bacterial burden. Therapeutic failures associated with multidrug-resistant, extended-spectrum β-lactamase (ESBL)–producing E. coli infections were detected in real time. Together, these data show that 18F-FDS is a candidate imaging probe for translation to human clinical cases of known or suspected infections owing to Enterobacteriaceae. PMID:25338757

AVERAGE SPATIAL DISTRIBUTION OF COSMIC RAYS BEHIND THE INTERPLANETARY SHOCK—GLOBAL MUON DETECTOR NETWORK OBSERVATIONS

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

Kozai, M.; Munakata, K.; Kato, C.

2016-07-10

We analyze the galactic cosmic ray (GCR) density and its spatial gradient in Forbush Decreases (FDs) observed with the Global Muon Detector Network (GMDN) and neutron monitors (NMs). By superposing the GCR density and density gradient observed in FDs following 45 interplanetary shocks (IP-shocks), each associated with an identified eruption on the Sun, we infer the average spatial distribution of GCRs behind IP-shocks. We find two distinct modulations of GCR density in FDs, one in the magnetic sheath and the other in the coronal mass ejection (CME) behind the sheath. The density modulation in the sheath is dominant in themore » western flank of the shock, while the modulation in the CME ejecta stands out in the eastern flank. This east–west asymmetry is more prominent in GMDN data responding to ∼60 GV GCRs than in NM data responding to ∼10 GV GCRs, because of the softer rigidity spectrum of the modulation in the CME ejecta than in the sheath. The geocentric solar ecliptic- y component of the density gradient, G {sub y}, shows a negative (positive) enhancement in FDs caused by the eastern (western) eruptions, while G {sub z} shows a negative (positive) enhancement in FDs caused by the northern (southern) eruptions. This implies that the GCR density minimum is located behind the central flank of IP-shocks and propagating radially outward from the location of the solar eruption. We also confirmed that the average G {sub z} changes its sign above and below the heliospheric current sheet, in accord with the prediction of the drift model for the large-scale GCR transport in the heliosphere.« less

Water consumption, grain yield, and water productivity in response to field water management in double rice systems in China.

PubMed

Wu, Xiao Hong; Wang, Wei; Yin, Chun Mei; Hou, Hai Jun; Xie, Ke Jun; Xie, Xiao Li

2017-01-01

Rice cultivation has been challenged by increasing food demand and water scarcity. We examined the responses of water use, grain yield, and water productivity to various modes of field water managements in Chinese double rice systems. Four treatments were studied in a long-term field experiment (1998-2015): continuous flooding (CF), flooding-midseason drying-flooding (F-D-F), flooding-midseason drying-intermittent irrigation without obvious standing water (F-D-S), and flooding-rain-fed (F-RF). The average precipitation was 483 mm in early-rice season and 397 mm in late-rice season. The irrigated water for CF, F-D-F, F-D-S, and F-RF, respectively, was 263, 340, 279, and 170 mm in early-rice season, and 484, 528, 422, and 206 mm in late-rice season. Grain yield for CF, F-D-F, F-D-S, and F-RF, respectively, was 4,722, 4,597, 4,479, and 4,232 kgha-1 in early-rice season, and 5,420, 5,402, 5,366, and 4,498 kgha-1 in late-rice season. Compared with CF, F-D-F consumed more irrigated water, which still decreased grain yield, leading to a decrease in water productivity by 25% in early-rice season and by 8% in late-rice season. Compared with F-D-F, F-D-S saved much irrigated water with a small yield reduction, leading to an increase in water productivity by 22% in early-rice season and by 26% in late-rice season. The results indicate that CF is best for early-rice and FDS is best for late-rice in terms of grain yield and water productivity.

Effects of two educational programmes aimed at improving the utilization of non-opioid analgesics in family medicine clinics in Mexico.

PubMed

Doubova, Svetlana Vladislavovna; Mino-León, Dolores; Reyes-Morales, Hortensia; Flores-Hernandez, Sergio; Torres-Arreola, Laura del Pilar; Pérez-Cuevas, Ricardo

2010-08-01

To develop and test two educational programmes (interactive and passive) aimed at improving family doctors' (FD) prescribing practices and patient's knowledge and use of non-opioid analgesics (NOA). The educational programmes were conducted in two family medicine clinics by using a three-stage approach: baseline evaluation, design, and implementation of educational activities, and post-programme evaluation. An interactive educational programme (IEP) was compared with a passive educational programme (PEP); both were participated by FDs and patients. The IEP for FDs comprised of workshops, discussion groups, in-service training and guidelines, while for patients the IEP consisted of an interactive session with a video, leaflets and a discussion. The PEP consisted in delivering the guidelines to the FDs and the leaflets to patients. The effect of the programmes on the FDs was measured through the appropriateness of prescriptions and analysed using the differences-in-differences estimator (D-in-D), and on patients through changes in self-medication and in their knowledge about the proper use and adverse events by analysing the inter- and intra-group differences before and after the programmes. The IEP obtained better results to improve appropriate FDs prescription of NOA than PEP (D-in-D = 15%). Regarding the patients, the PEP group reached higher reduction of self-medication than the IEP group (13.4% vs. 9.1%); the knowledge of proper NOA use increased by 8.5% in both groups, whereas knowledge of NOA-related adverse events was better in the IEP (39.6%) than in the PEP group (9.2%). The IEP was better to improve the doctors' abilities to prescribe NOAs, and both programmes improved patients' knowledge.

The Functional Dysphagia Scale Is a Useful Tool for Predicting Aspiration Pneumonia in Patients With Parkinson Disease.

PubMed

Lee, Jong Hwa; Lee, Kyeong Woo; Kim, Sang Beom; Lee, Sook Joung; Chun, Sang Myung; Jung, Sung Moon

2016-06-01

To describe the correlation between the functional dysphagia scale and aspiration pneumonia and which characteristics influence the occurrence of aspiration pneumonia in patients with idiopathic Parkinson disease. Fifty-three patients with idiopathic Parkinson disease were prospectively evaluated in this study. Disease severity and functional status were measured by modified Hoehn and Yahr (H&Y) staging, Schwab and England activities of daily living (S-E ADL) scale and Korean version of Mini-Mental State Examination (K-MMSE). Swallowing function was evaluated by the functional dysphagia scale (FDS) and the penetration-aspiration scale (PAS) based on a videofluoroscopic swallowing study. The patients were followed up for 3 months and divided into two groups according to the occurrence of aspiration pneumonia. The correlation between the variables and aspiration pneumonia was analyzed. Eight patients of the 53 patients were allocated to the aspiration pneumonia group and 45 patients to the non-aspiration pneumonia group. The patients in the aspiration pneumonia group had significantly higher H&Y staging, and scored lower on S-E ADL scale and K-MMSE. The patients in the aspiration pneumonia group had significantly higher scores on FDS and PAS. A multiple logistic regression analysis showed that the S-E ADL scale and the FDS were associated with the occurrence of aspiration pneumonia in the patients with Parkinson disease. Given that the FDS can quantitatively assess the functional problems associated with dysphagia, it can be clinically effective in predicting the occurrence of aspiration pneumonia, and the FDS and the S-E ADL scale could be predictive variables for aspiration pneumonia in patients with Parkinson disease.

Effect of electronic prescribing with formulary decision support on medication use and cost.

PubMed

Fischer, Michael A; Vogeli, Christine; Stedman, Margaret; Ferris, Timothy; Brookhart, M Alan; Weissman, Joel S

2008-12-08

Electronic prescribing (e-prescribing) with formulary decision support (FDS) prompts prescribers to prescribe lower-cost medications and may help contain health care costs. In April 2004, 2 large Massachusetts insurers began providing an e-prescribing system with FDS to community-based practices. Using 18 months (October 1, 2003, to March 31, 2005) of administrative data, we conducted a pre-post study with concurrent controls. We first compared the change in the proportion of prescriptions for 3 formulary tiers before and after e-prescribing began, then developed multivariate longitudinal models to estimate the specific effect of e-prescribing when controlling for baseline differences between intervention and control prescribers. Potential savings were estimated using average medication costs by formulary tier. More than 1.5 million patients filled 17.4 million prescriptions during the study period. Multivariate models controlling for baseline differences between prescribers and for changes over time estimated that e-prescribing corresponded to a 3.3% increase (95% confidence interval, 2.7%-4.0%) in tier 1 prescribing. The proportion of prescriptions for tiers 2 and 3 (brand-name medications) decreased correspondingly. e-Prescriptions accounted for 20% of filled prescriptions in the intervention group. Based on average costs for private insurers, we estimated that e-prescribing with FDS at this rate could result in savings of $845,000 per 100,000 patients. Higher levels of e-prescribing use would increase these savings. Clinicians using e-prescribing with FDS were significantly more likely to prescribe tier 1 medications, and the potential financial savings were substantial. Widespread use of e-prescribing systems with FDS could result in reduced spending on medications.

The Combined Use of Intraluminal and Intrasaccular Flow Diversion for the Treatment of Intracranial Aneurysms: Report of 25 Cases

PubMed Central

AlMatter, Muhammad; Hellstern, Victoria; Ganslandt, Oliver; Bäzner, Hansjörg; Henkes, Hans; Aguilar-Pérez, Marta

2018-01-01

Purpose The Medina Embolic Device (MED) is a new intrasaccular device with promising early results. Previously we documented our initial experience of this device both alone and in combination with other devices including flow diverter stents (FDS). We sought to determine the effect of the MED + FDS strategy for the treatment of selected aneurysms. Materials and Methods We performed a retrospective analysis of prospectively collected data to identify all patients with aneurysms treated using both the MED and intraluminal FDS. We present our technical success rate, early and mid-term angiographic follow-up, and clinical outcome data. Results We identified 25 non-consecutive patients. The treatment was staged in 9 patients and in a single session 16 patients. The average age was 61±12.8 years (range 40–82). The average fundus height was 11±3.6 mm and average fundus width was 10.1±3.4 mm. In the staged cohort (n=9) at delayed angiography (mean 10 mths) 8 aneurysms (89%) showed complete exclusion (mRRC 1) and in one patient there was a parent vessel occlusion. In the simultaneous cohort delayed angiography (n=10, mean 8.1 months) demonstrated complete occlusion (mRRC 1) in 6 aneurysms (60%), 3 neck remnants (mRRC 2) (30%) and 1 patient (10%) showed persistent aneurysmal filling (mRRC 3a). There were 5 complications with permanent morbidity (mRS >2) in two patients. There were no mortalities. Conclusion The MED can be successfully used in combination with intraluminal FDS and in selected aneurysms this may represent an alternative to FDS and adjunctive coiling. PMID:29535895

Estimation of number of fatalities caused by toxic gases due to fire in road tunnels.

PubMed

Qu, Xiaobo; Meng, Qiang; Liu, Zhiyuan

2013-01-01

The quantitative risk assessment (QRA) is one of the explicit requirements under the European Union (EU) Directive (2004/54/EC). As part of this, it is essential to be able to estimate the number of fatalities in different accident scenarios. In this paper, a tangible methodology is developed to estimate the number of fatalities caused by toxic gases due to fire in road tunnels by incorporating traffic flow and the spread of fire in tunnels. First, a deterministic queuing model is proposed to calculate the number of people at risk, by taking into account tunnel geometry, traffic flow patterns, and incident response plans for road tunnels. Second, the Fire Dynamics Simulator (FDS) is used to obtain the temperature and concentrations of CO, CO(2), and O(2). By taking advantage of the additivity of the fractional effective dose (FED) method, fatality rates for different locations in given time periods can be estimated. An illustrative case study is carried out to demonstrate the applicability of the proposed methodology. Copyright © 2012 Elsevier Ltd. All rights reserved.

Consequences of repetitive toenail cutting by podiatric physicians on force production, endurance to fatigue, and the electromyogram of the flexor digitorum superficialis muscles.

PubMed

Vie, Bruno; Loffredo, Remy; Sanahdji, Farid; Weber, Jean-Paul; Jammes, Yves

2014-01-01

We hypothesized that the repetitive use of a toenail clipper by podiatric physicians could induce fatigue of the flexor digitorum superficialis (FDS) muscle, reducing the accuracy of toenail cutting. We examined the consequences of cutting a plastic sheet, reproducing the resistance of thick toenails, with a podiatric medical clipper on the maximal handgrip force (Fmax) developed by the FDS muscle and an isometric handgrip sustained at 50% of Fmax, during which endurance to fatigue and changes in the power spectra of the surface FDS muscle electromyogram (root mean square and median frequency) were measured. The same participants randomly performed one or five runs of 30 successive cuttings, each on different days. After the first and fifth cutting runs, Fmax increased, suggesting a post-tetanic potentiation. During the handgrip sustained at 50% of Fmax, we measured a significant reduction in the tension-time index after the first cutting run. Moreover, after the fifth cutting run, the tension-time index decrease was significantly accentuated, and the decrease in FDS muscle median frequency was enhanced. No median frequency decline was measured during the cutting runs. These results suggest that the efficacy of occupational podiatric medical tasks progressively declines with the repetition of toenail cutting. We propose solutions to remedy this situation.

Implementation and Test of the Automatic Flight Dynamics Operations for Geostationary Satellite Mission

NASA Astrophysics Data System (ADS)

Park, Sangwook; Lee, Young-Ran; Hwang, Yoola; Javier Santiago Noguero Galilea

2009-12-01

This paper describes the Flight Dynamics Automation (FDA) system for COMS Flight Dynamics System (FDS) and its test result in terms of the performance of the automation jobs. FDA controls the flight dynamics functions such as orbit determination, orbit prediction, event prediction, and fuel accounting. The designed FDA is independent from the specific characteristics which are defined by spacecraft manufacturer or specific satellite missions. Therefore, FDA could easily links its autonomous job control functions to any satellite mission control system with some interface modification. By adding autonomous system along with flight dynamics system, it decreases the operator’s tedious and repeated jobs but increase the usability and reliability of the system. Therefore, FDA is used to improve the completeness of whole mission control system’s quality. The FDA is applied to the real flight dynamics system of a geostationary satellite, COMS and the experimental test is performed. The experimental result shows the stability and reliability of the mission control operations through the automatic job control.

Stable and low diffusive hybrid upwind splitting methods

NASA Technical Reports Server (NTRS)

Coquel, Frederic; Liou, Meng-Sing

1992-01-01

A new concept for upwinding is introduced, named the hybrid upwind splitting (HUS), which is achieved by combining the basically distinct flux vector splitting (FVS) and the flux difference splitting (FDS) approaches. The HUS approach yields upwind methods which share the robustness of the FVS schemes in the capture of nonlinear waves and the accuracy of some of the FDS schemes. Numerical illustrations are presented proving the relevance of the HUS methods for viscous calculations.

QUALITY IMPROVEMENT COMPETENCY GAPS IN PRIMARY CARE IN ALBANIAN, POLISH AND SLOVENIAN CONTEXTS: A STUDY PROTOCOL

PubMed Central

Czabanowska, Katarzyna; Burazeri, Genc; Klemenc-Ketis, Zalika; Kijowska, Violetta; Tomasik, Tomasz; Brand, Helmut

2012-01-01

Background: Nowadays, general practitioners (GPs) and family doctors (FDs) face increasing demands, as a consequence of complex patients’ expectations, developments in science and technology, and limitations within healthcare systems which can result in competency gaps. Therefore, there is a need to identify which competencies in quality improvement (QI) are most important for GPs and FDs to possess in order to meet the demands of contemporary health care practice. To date, however, little information is available on the self-assessment of competencies related to QI among GPs and FDs. To deal with these issues, a project on QI in continuous medical education was launched in 2011. The project aims to broaden the GPs’/ FDs’ continuous education offer, its quality and attractiveness, as well as provide them with opportunities for vocational advancement and enable the development of common, European frame of reference for GPs’/FDs’ occupational competencies. The third work package of the project consists of the validation research of the questionnaire developed on the basis of the competency framework in QI for GPs/FDs in Europe. Methods: A cross-sectional study will be carried out using the self-assessment QI questionnaire which was originally developed in English and subsequently it was cross-culturally adapted in Slovenian, Albanian and Polish settings by use of a pilot study on a conveniently selected group of FDs/GPs (N=10) in each participating country. The final version of the questionnaire will be administered to large samples in each country involved in the survey. Two weeks after the first administration of the questionnaire, a second round, with the same procedure and including the same group of respondents, will follow. Psychometric tests will be conducted including internal consistency (after the initial and subsequent application of the instrument) and stability over time (two-week test-retest reliability). Discussion: This self-assessment study will demonstrate the complex environment in which general practice/family medicine operates and, eventually, this gap analysis will set out strategically important areas for collaborative efforts related to QI in primary care. The authors consider that the study should be extended to other European countries to help identify most required competencies that GPs/FDs should possess in Europe and thus stir system and educational debate around QI curricula and training for primary care in Europe. PMID:23378694

Polymorphism at a mimicry supergene maintained by opposing frequency-dependent selection pressures.

PubMed

Chouteau, Mathieu; Llaurens, Violaine; Piron-Prunier, Florence; Joron, Mathieu

2017-08-01

Explaining the maintenance of adaptive diversity within populations is a long-standing goal in evolutionary biology, with important implications for conservation, medicine, and agriculture. Adaptation often leads to the fixation of beneficial alleles, and therefore it erodes local diversity so that understanding the coexistence of multiple adaptive phenotypes requires deciphering the ecological mechanisms that determine their respective benefits. Here, we show how antagonistic frequency-dependent selection (FDS), generated by natural and sexual selection acting on the same trait, maintains mimicry polymorphism in the toxic butterfly Heliconius numata Positive FDS imposed by predators on mimetic signals favors the fixation of the most abundant and best-protected wing-pattern morph, thereby limiting polymorphism. However, by using mate-choice experiments, we reveal disassortative mate preferences of the different wing-pattern morphs. The resulting negative FDS on wing-pattern alleles is consistent with the excess of heterozygote genotypes at the supergene locus controlling wing-pattern variation in natural populations of H. numata The combined effect of positive and negative FDS on visual signals is sufficient to maintain a diversity of morphs displaying accurate mimicry with other local prey, although some of the forms only provide moderate protection against predators. Our findings help understand how alternative adaptive phenotypes can be maintained within populations and emphasize the need to investigate interactions between selective pressures in other cases of puzzling adaptive polymorphism.

Polymorphism at a mimicry supergene maintained by opposing frequency-dependent selection pressures

PubMed Central

Chouteau, Mathieu; Llaurens, Violaine; Piron-Prunier, Florence; Joron, Mathieu

2017-01-01

Explaining the maintenance of adaptive diversity within populations is a long-standing goal in evolutionary biology, with important implications for conservation, medicine, and agriculture. Adaptation often leads to the fixation of beneficial alleles, and therefore it erodes local diversity so that understanding the coexistence of multiple adaptive phenotypes requires deciphering the ecological mechanisms that determine their respective benefits. Here, we show how antagonistic frequency-dependent selection (FDS), generated by natural and sexual selection acting on the same trait, maintains mimicry polymorphism in the toxic butterfly Heliconius numata. Positive FDS imposed by predators on mimetic signals favors the fixation of the most abundant and best-protected wing-pattern morph, thereby limiting polymorphism. However, by using mate-choice experiments, we reveal disassortative mate preferences of the different wing-pattern morphs. The resulting negative FDS on wing-pattern alleles is consistent with the excess of heterozygote genotypes at the supergene locus controlling wing-pattern variation in natural populations of H. numata. The combined effect of positive and negative FDS on visual signals is sufficient to maintain a diversity of morphs displaying accurate mimicry with other local prey, although some of the forms only provide moderate protection against predators. Our findings help understand how alternative adaptive phenotypes can be maintained within populations and emphasize the need to investigate interactions between selective pressures in other cases of puzzling adaptive polymorphism. PMID:28673971

A new numerical approach to solve Thomas-Fermi model of an atom using bio-inspired heuristics integrated with sequential quadratic programming.

PubMed

Raja, Muhammad Asif Zahoor; Zameer, Aneela; Khan, Aziz Ullah; Wazwaz, Abdul Majid

2016-01-01

In this study, a novel bio-inspired computing approach is developed to analyze the dynamics of nonlinear singular Thomas-Fermi equation (TFE) arising in potential and charge density models of an atom by exploiting the strength of finite difference scheme (FDS) for discretization and optimization through genetic algorithms (GAs) hybrid with sequential quadratic programming. The FDS procedures are used to transform the TFE differential equations into a system of nonlinear equations. A fitness function is constructed based on the residual error of constituent equations in the mean square sense and is formulated as the minimization problem. Optimization of parameters for the system is carried out with GAs, used as a tool for viable global search integrated with SQP algorithm for rapid refinement of the results. The design scheme is applied to solve TFE for five different scenarios by taking various step sizes and different input intervals. Comparison of the proposed results with the state of the art numerical and analytical solutions reveals that the worth of our scheme in terms of accuracy and convergence. The reliability and effectiveness of the proposed scheme are validated through consistently getting optimal values of statistical performance indices calculated for a sufficiently large number of independent runs to establish its significance.

Analysis of a Smartphone-Based Architecture with Multiple Mobility Sensors for Fall Detection with Supervised Learning

PubMed Central

Santoyo-Ramón, José Antonio

2018-01-01

This paper describes a wearable Fall Detection System (FDS) based on a body-area network consisting of four nodes provided with inertial sensors and Bluetooth wireless interfaces. The signals captured by the nodes are sent to a smartphone which simultaneously acts as another sensing point. In contrast to many FDSs proposed by the literature (which only consider a single sensor), the multisensory nature of the prototype is utilized to investigate the impact of the number and the positions of the sensors on the effectiveness of the production of the fall detection decision. In particular, the study assesses the capability of four popular machine learning algorithms to discriminate the dynamics of the Activities of Daily Living (ADLs) and falls generated by a set of experimental subjects, when the combined use of the sensors located on different parts of the body is considered. Prior to this, the election of the statistics that optimize the characterization of the acceleration signals and the efficacy of the FDS is also investigated. As another important methodological novelty in this field, the statistical significance of all the results (an aspect which is usually neglected by other works) is validated by an analysis of variance (ANOVA). PMID:29642638

Working memory span in Persian-speaking children with speech sound disorders and normal speech development.

PubMed

Afshar, Mohamad Reza; Ghorbani, Ali; Rashedi, Vahid; Jalilevand, Nahid; Kamali, Mohamad

2017-10-01

The aim of this study was to compare working memory span in Persian-speaking preschool children with speech sound disorder (SSD) and their typically speaking peers. Additionally, the study aimed to examine Non-Word Repetition (NWR), Forward Digit Span (FDS) and Backward Digit Span (BDS) in four groups of children with varying severity levels of SSD. The participants in this study comprised 35 children with SSD and 35 typically developing (TD) children -matched for age and sex-as a control group. The participants were between the age range of 48 and 72 months. Two components of working memory including phonological loop and central executive were compared between two groups. We used two tasks (NWR and FDS) to assess phonological loop component, and one task (BDS) to assess central executive component. Percentage of correct consonants (PCC) was used to calculate the severity of SSD. Significant differences were observed between the two groups in all tasks that assess working memory (p < 0.001). In addition, the comparison of the phonological loop of working memory between the various severity groups indicated significant differences between different severities of both NWR and FDS tasks among the SSD children (p < 0.001). Nevertheless, comparison of the central executive between various severity groups, which was assessed with the BDS task, did not show any significant differences (p > 0.05). The result showed that PCC scores in TD children were associated with NWR (p < 0.001), FDS (p = 0.001), and BDS (p < 0.001). Furthermore, PCC scores in SSD children were associated with NWR and FDS (p < 0.001), but not with BDS (p > 0.05). The working memory skills were weaker in SSD children, in comparison to TD children. In addition, children with varying levels of severity of SSD differed in terms of NWR and FSD, but not BDS. Copyright © 2017 Elsevier B.V. All rights reserved.

De novo transcriptomic analysis during Lentinula edodes fruiting body growth.

PubMed

Wang, Yingzhu; Zeng, Xianlu; Liu, Wenguang

2018-01-30

The fruiting body of Lentinula edodes is a popular edible mushroom, and extracts from the mycelium and the fruiting body of this species have diverse therapeutic potential. To gain insights into the molecular mechanisms underlying the fruiting body growth of L. edodes from the early bud stage (EBS), through the intermediate developing stage (IDS), to the fully developed stage (FDS), we performed de novo transcriptomic analysis using high-throughput Illumina RNA-sequencing. First, we generated three cDNA libraries representative of the three respective stages. We then obtained 38,933,148, 44,594,472, and 37,905,646 high-quality reads from the respective libraries and assembled the reads into 25,104 transcriptional contigs, containing 15,199 unigenes. We found that only 9331 of the unigenes had been annotated in the NCBI non-redundant protein database, and we functionally annotated 4758 of them through Gene Ontology (GO) analysis and 2921 of them through Clusters of Orthologous Groups of proteins (COGs) analysis. We also assigned 3995 unigenes to metabolic pathways by using the Kyoto Encyclopedia of Genes and Genomes (KEGG). We further identified 399 differentially expressed genes (DEGs) between EBS and IDS, 1428 between IDS and FDS, and 1830 between EBS and FDS, uncovering 769 DEGs in multiple metabolic and signaling pathways. Interestingly, there were a limited number of DEGs whose expression was dramatically associated with FDS. Finally, genes, whose expression was either highly up-regulated in FDS or remained at a high level during fruiting body growth, were annotated specifically in the pathways of purine metabolism, unsaturated fatty acid metabolism and meiosis, suggesting that these key molecular events were actively occurring in the fruiting body. Our work is the first high-throughput transcriptome study on the growth of L. edodes fruiting bodies, and the results uncovered candidate genes for future gene identification and utilization of this commercially and medically important mushroom. Copyright © 2017 Elsevier B.V. All rights reserved.

Fiber optic-based fluorescence detection system for in vivo studies of exogenous chromophore pharmacokinetics

NASA Astrophysics Data System (ADS)

Doiron, Daniel R.; Dunn, J. B.; Mitchell, W. L.; Dalton, Brian K.; Garbo, Greta M.; Warner, Jon A.

1995-05-01

The detection and quantification of the concentration of exogenous chromophores in-vivo by their fluorescence is complicated by many physical and geometrical parameters. Measurement of such signals is advantageous in determining the pharmacokinetics of photosensitizers such as those used in photodynamic therapy (PDT) or to assist in the diagnosis of tissue histological state. To overcome these difficulties a ratio based fiber optic contact fluorometer has been developed. This fluorescence detection system (FDS) uses the ratio of the fluorescence emission peak of the exogenous chromophore to that of endogenous chromophores, i.e. autofluorescence, to correct for a variety of parameters affecting the magnitude of the measured signals. By doing so it also minimizes the range of baseline measurements prior to exogenous drug injection, for various tissue types. Design of the FDS and results of its testing in animals and patients using the second generation photosensitizer Tin ethyletiopurpurin (SnET2) are presented. These results support the feasibility and usefulness of the Ratio FDS system.

Resident training in a teaching hospital: How do attendings teach in the real operative environment?

PubMed

Glarner, Carly E; Law, Katherine E; Zelenski, Amy B; McDonald, Robert J; Greenberg, Jacob A; Foley, Eugene F; Wiegmann, Douglas A; Greenberg, Caprice C

2017-07-01

The study aim was to explore the nature of intraoperative education and its interaction with the environment where surgical education occurs. Video and audio recording captured teaching interactions between colorectal surgeons and general surgery residents during laparoscopic segmental colectomies. Cases and collected data were analyzed for teaching behaviors and workflow disruptions. Flow disruptions (FDs) are considered deviations from natural case progression. Across 10 cases (20.4 operative hours), attendings spent 11.2 hours (54.7%) teaching, using directing (M = 250.1), and confirming (M = 236.1) most. FDs occurred 410 times, accounting for 4.4 hours of case time (21.57%). Teaching occurred with FD events for 2.4 hours (22.2%), whereas 77.8% of teaching happened outside FD occurrence. Teaching methods shifted from active to passive during FD events to compensate for patient safety. Understanding how FDs impact operative learning will inform faculty development in managing interruptions and improve its integration into resident education. Copyright © 2016. Published by Elsevier Inc.

Meeting report: ‘How do I incorporate research into my family practice?’: Reflections on experiences of and solutions for young family doctors

PubMed Central

2018-01-01

Background Family doctors (FDs) focus on biopsychosocial components of health during consultations. However, much of the evidence employed by these doctors is produced by researchers who are not routinely involved in family practice. Family doctors competent in both clinical practice and research are essential to addressing this gap. With the growing recognition of family medicine as the specialty of choice for many young doctors, there is a scarcity of literature that describes their experiences in combining research and daily family practice. Aim Members from Young Doctor Movements (YDMs) under the auspices of the World Organisation of Family Doctors (WONCA) sought to address this knowledge gap by reflecting on their experiences towards becoming researchers. With the assistance of senior doctors, they explored solutions that can help young FDs incorporate research into their family practice. Methods Following an online YDM meeting, a summary of the experiences of young FDs as well as strategies useful for incorporating research into their everyday practice as FDs was prepared. Result Nine thematic areas were derived, including experiences and motivation towards regular research, culture and environment of practice, relevance and gains of research, teamwork and mentorship. Conclusion Family practices can incorporate research by promoting a personal and organisational research culture, highlighting gains and relevance of making it part of the profession and fostering teamwork, supportive networks and mentorship while making it enjoyable. PMID:29781695

Involuntary Neuromuscular Coupling between the Thumb and Finger of Stroke Survivors during Dynamic Movement.

PubMed

Jones, Christopher L; Kamper, Derek G

2018-01-01

Finger-thumb coordination is crucial to manual dexterity but remains incompletely understood, particularly following neurological injury such as stroke. While being controlled independently, the index finger and thumb especially must work in concert to perform a variety of tasks requiring lateral or palmar pinch. The impact of stroke on this functionally critical sensorimotor control during dynamic tasks has been largely unexplored. In this study, we explored finger-thumb coupling during close-open pinching motions in stroke survivors with chronic hemiparesis. Two types of perturbations were applied randomly to the index with a novel Cable-Actuated Finger Exoskeleton: a sudden joint acceleration stretching muscle groups of the index finger and a sudden increase in impedance in selected index finger joint(s). Electromyographic signals for specific thumb and index finger muscles, thumb tip trajectory, and index finger joint angles were recorded during each trial. Joint angle perturbations invoked reflex responses in the flexor digitorum superficialis (FDS), first dorsal interossei (FDI), and extensor digitorum communis muscles of the index finger and heteronymous reflex responses in flexor pollicis brevis of the thumb ( p  < 0.017). Phase of movement played a role as a faster peak reflex response was observed in FDI during opening than during closing ( p  < 0.002) and direction of perturbations resulted in shorter reflex times for FDS and FDI ( p  < 0.012) for extension perturbations. Surprisingly, when index finger joint impedance was suddenly increased, thumb tip movement was substantially increased, from 2 to 10 cm ( p  < 0.001). A greater effect was seen during the opening phase ( p  < 0.044). Thus, involuntary finger-thumb coupling was present during dynamic movement, with perturbation of the index finger impacting thumb activity. The degree of coupling modulated with the phase of motion. These findings reveal a potential mechanism for direct intervention to improve poststroke hand mobility and provide insight on prospective neurologically oriented therapies.

Involuntary Neuromuscular Coupling between the Thumb and Finger of Stroke Survivors during Dynamic Movement

PubMed Central

Jones, Christopher L.; Kamper, Derek G.

2018-01-01

Finger–thumb coordination is crucial to manual dexterity but remains incompletely understood, particularly following neurological injury such as stroke. While being controlled independently, the index finger and thumb especially must work in concert to perform a variety of tasks requiring lateral or palmar pinch. The impact of stroke on this functionally critical sensorimotor control during dynamic tasks has been largely unexplored. In this study, we explored finger–thumb coupling during close–open pinching motions in stroke survivors with chronic hemiparesis. Two types of perturbations were applied randomly to the index with a novel Cable-Actuated Finger Exoskeleton: a sudden joint acceleration stretching muscle groups of the index finger and a sudden increase in impedance in selected index finger joint(s). Electromyographic signals for specific thumb and index finger muscles, thumb tip trajectory, and index finger joint angles were recorded during each trial. Joint angle perturbations invoked reflex responses in the flexor digitorum superficialis (FDS), first dorsal interossei (FDI), and extensor digitorum communis muscles of the index finger and heteronymous reflex responses in flexor pollicis brevis of the thumb (p < 0.017). Phase of movement played a role as a faster peak reflex response was observed in FDI during opening than during closing (p < 0.002) and direction of perturbations resulted in shorter reflex times for FDS and FDI (p < 0.012) for extension perturbations. Surprisingly, when index finger joint impedance was suddenly increased, thumb tip movement was substantially increased, from 2 to 10 cm (p < 0.001). A greater effect was seen during the opening phase (p < 0.044). Thus, involuntary finger–thumb coupling was present during dynamic movement, with perturbation of the index finger impacting thumb activity. The degree of coupling modulated with the phase of motion. These findings reveal a potential mechanism for direct intervention to improve poststroke hand mobility and provide insight on prospective neurologically oriented therapies. PMID:29545767

Mechanical Strength of the Side-to-Side Versus Pulvertaft Weave Tendon Repair

PubMed Central

Brown, Stephen H. M.; Hentzen, Eric R.; Kwan, Alan; Ward, Samuel R.; Fridén, Jan; Lieber, Richard L.

2010-01-01

Purpose The side-to-side (SS) tendon suture technique was designed to function as a repair that permits immediate post-operative activation and mobilization of a transferred muscle. This study was designed to test the strength and stiffness of the SS technique against a variation of the Pulvertaft (PT) repair technique. Methods Flexor digitorum superficialis (FDS) and flexor digitorum profundus (FDP) tendons were harvested from four fresh cadavers and used as a model system. Seven SS and six PT repairs were performed using the FDS as the donor and the FDP as the recipient tendon. For SS repairs, the FDS was woven through one incision in the FDP, and was joined with four cross-stitch running sutures down both sides, and one double-loop suture at each tendon free end; for PT repairs, FDS was woven through three incisions in FDP, joined with a double-loop suture at both ends of the overlap, and four evenly spaced mattress sutures between the ends. Tendon repairs were placed in a tensile testing machine, pre-conditioned and tested to failure. Results There were no statistically significant differences in cross-sectional area (p=0.99) or initial length (p=0.93) between SS and PT repairs. Therefore, all comparisons between methods were made using measures of loads and deformations, rather than stresses and strains.. All failures occurred in the repair region, rather than at the clamps. However, failure mechanisms were different between the two techniques—PT repairs failed by the suture knots either slipping or pulling through the tendon material, followed by the FDS tendon pulling through the FDP tendon; SS repairs failed by shearing of fibers within the FDS. Load at first failure (p < 0.01), ultimate load (p < 0.001), and repair stiffness (p < 0.05) were all significantly different between SS and PT techniques; in all cases the mean value for SS was higher than for PT. Discussion The SS repair, using a cross-stitch suture technique, was significantly stronger and stiffer compared to the PT repair using a mattress suture technique. This suggests that using SS repairs could enable patients to load the repair soon after surgery. Ultimately, this should reduce the risk of developing adhesions and result in improved functional outcome and fewer complications in the acute post-operative period. Future work will address the specific mechanisms (for example, suture-throw technique, tendon-weave technique) that underlie the improved strength and stiffness of the SS repair. PMID:20223604

Field modeling of heat transfer in atrium

NASA Astrophysics Data System (ADS)

Nedryshkin, Oleg; Gravit, Marina; Bushuev, Nikolay

2017-10-01

The results of calculating fire risk are an important element in the system of modern fire safety assessment. The article reviews the work on the mathematical modeling of fire in the room. A comparison of different calculation models in the programs of fire risk assessment and fire modeling was performed. The results of full-scale fire tests and fire modeling in the FDS program are presented. The analysis of empirical and theoretical data on fire modeling is made, a conclusion is made about the modeling accuracy in the FDS program.

Image based Monte Carlo Modeling for Computational Phantom

NASA Astrophysics Data System (ADS)

Cheng, Mengyun; Wang, Wen; Zhao, Kai; Fan, Yanchang; Long, Pengcheng; Wu, Yican

2014-06-01

The evaluation on the effects of ionizing radiation and the risk of radiation exposure on human body has been becoming one of the most important issues for radiation protection and radiotherapy fields, which is helpful to avoid unnecessary radiation and decrease harm to human body. In order to accurately evaluate the dose on human body, it is necessary to construct more realistic computational phantom. However, manual description and verfication of the models for Monte carlo(MC)simulation are very tedious, error-prone and time-consuming. In addiation, it is difficult to locate and fix the geometry error, and difficult to describe material information and assign it to cells. MCAM (CAD/Image-based Automatic Modeling Program for Neutronics and Radiation Transport Simulation) was developed as an interface program to achieve both CAD- and image-based automatic modeling by FDS Team (Advanced Nuclear Energy Research Team, http://www.fds.org.cn). The advanced version (Version 6) of MCAM can achieve automatic conversion from CT/segmented sectioned images to computational phantoms such as MCNP models. Imaged-based automatic modeling program(MCAM6.0) has been tested by several medical images and sectioned images. And it has been applied in the construction of Rad-HUMAN. Following manual segmentation and 3D reconstruction, a whole-body computational phantom of Chinese adult female called Rad-HUMAN was created by using MCAM6.0 from sectioned images of a Chinese visible human dataset. Rad-HUMAN contains 46 organs/tissues, which faithfully represented the average anatomical characteristics of the Chinese female. The dose conversion coefficients(Dt/Ka) from kerma free-in-air to absorbed dose of Rad-HUMAN were calculated. Rad-HUMAN can be applied to predict and evaluate dose distributions in the Treatment Plan System (TPS), as well as radiation exposure for human body in radiation protection.

A de novo missense mutation of FGFR2 causes facial dysplasia syndrome in Holstein cattle.

PubMed

Agerholm, Jørgen S; McEvoy, Fintan J; Heegaard, Steffen; Charlier, Carole; Jagannathan, Vidhya; Drögemüller, Cord

2017-08-02

Surveillance for bovine genetic diseases in Denmark identified a hitherto unreported congenital syndrome occurring among progeny of a Holstein sire used for artificial breeding. A genetic aetiology due to a dominant inheritance with incomplete penetrance or a mosaic germline mutation was suspected as all recorded cases were progeny of the same sire. Detailed investigations were performed to characterize the syndrome and to reveal its cause. Seven malformed calves were submitted examination. All cases shared a common morphology with the most striking lesions being severe facial dysplasia and complete prolapse of the eyes. Consequently the syndrome was named facial dysplasia syndrome (FDS). Furthermore, extensive brain malformations, including microencephaly, hydrocephalus, lobation of the cerebral hemispheres and compression of the brain were present. Subsequent data analysis of progeny of the sire revealed that around 0.5% of his offspring suffered from FDS. High density single nucleotide polymorphism (SNP) genotyping data of the seven cases and their parents were used to map the defect in the bovine genome. Significant genetic linkage was obtained for three regions, including chromosome 26 where whole genome sequencing of a case-parent trio revealed two de novo variants perfectly associated with the disease: an intronic SNP in the DMBT1 gene and a single non-synonymous variant in the FGFR2 gene. This FGFR2 missense variant (c.927G>T) affects a gene encoding a member of the fibroblast growth factor receptor family, where amino acid sequence is highly conserved between members and across species. It is predicted to change an evolutionary conserved tryptophan into a cysteine residue (p.Trp309Cys). Both variant alleles were proven to result from de novo mutation events in the germline of the sire. FDS is a novel genetic disorder of Holstein cattle. Mutations in the human FGFR2 gene are associated with various dominant inherited craniofacial dysostosis syndromes. Given the phenotypic similarities in FDS affected calves, the genetic mapping and absence of further high impact variants in the critical genome regions, it is highly likely that the missense mutation in the FGFR2 gene caused the FDS phenotype in a dominant mode of inheritance.

NUTS and BOLTS: Applications of Fluorescence Detected Sedimentation

PubMed Central

Kroe, Rachel R.; Laue, Thomas M.

2008-01-01

Analytical ultracentrifugation is a widely used method for characterizing the solution behavior of macromolecules. However, the two commonly used detectors (absorbance and interference) impose some fundamental restrictions on the concentrations and complexity of the solutions that can be analyzed. The recent addition of a fluorescence detector for the XL-I analytical ultracentrifuge (AU-FDS) enables two different types of sedimentation experiments. First, the AU-FDS can detect picomolar concentrations of labeled solutes allowing the characterization of very dilute solutions of macromolecules, applications we call Normal Use Tracer Sedimentation (NUTS). The great sensitivity of NUTS analysis allows the characterization of small quantities of materials and high affinity interactions. Second, AU-FDS allows characterization of trace quantities of labeled molecules in solutions containing high concentrations and complex mixtures of unlabeled molecules, applications we call Biological On Line Tracer Sedimentation (BOLTS). The discrimination of BOLTS enables the size distribution of a labeled macromolecule to be determined in biological milieu such as cell lysates and serum. Examples are presented that embody features of both NUTS and BOLTS applications, along with our observations on these applications. PMID:19103145

Analysis of Protein Interactions with Picomolar Binding Affinity by Fluorescence-Detected Sedimentation Velocity

PubMed Central

2014-01-01

The study of high-affinity protein interactions with equilibrium dissociation constants (KD) in the picomolar range is of significant interest in many fields, but the characterization of stoichiometry and free energy of such high-affinity binding can be far from trivial. Analytical ultracentrifugation has long been considered a gold standard in the study of protein interactions but is typically applied to systems with micromolar KD. Here we present a new approach for the study of high-affinity interactions using fluorescence detected sedimentation velocity analytical ultracentrifugation (FDS-SV). Taking full advantage of the large data sets in FDS-SV by direct boundary modeling with sedimentation coefficient distributions c(s), we demonstrate detection and hydrodynamic resolution of protein complexes at low picomolar concentrations. We show how this permits the characterization of the antibody–antigen interactions with low picomolar binding constants, 2 orders of magnitude lower than previously achieved. The strongly size-dependent separation and quantitation by concentration, size, and shape of free and complex species in free solution by FDS-SV has significant potential for studying high-affinity multistep and multicomponent protein assemblies. PMID:24552356

Measurement of B(Ds+→l+ν) and the decay constant fDS+

NASA Astrophysics Data System (ADS)

Pedlar, T. K.; Cronin-Hennessy, D.; Gao, K. Y.; Hietala, J.; Kubota, Y.; Klein, T.; Lang, B. W.; Poling, R.; Scott, A. W.; Smith, A.; Zweber, P.; Dobbs, S.; Metreveli, Z.; Seth, K. K.; Tomaradze, A.; Ernst, J.; Ecklund, K. M.; Severini, H.; Love, W.; Savinov, V.; Aquines, O.; Lopez, A.; Mehrabyan, S.; Mendez, H.; Ramirez, J.; Huang, G. S.; Miller, D. H.; Pavlunin, V.; Sanghi, B.; Shipsey, I. P. J.; Xin, B.; Adams, G. S.; Anderson, M.; Cummings, J. P.; Danko, I.; Hu, D.; Moziak, B.; Napolitano, J.; He, Q.; Insler, J.; Muramatsu, H.; Park, C. S.; Thorndike, E. H.; Yang, F.; Artuso, M.; Blusk, S.; Butt, J.; Khalil, S.; Li, J.; Menaa, N.; Mountain, R.; Nisar, S.; Randrianarivony, K.; Sia, R.; Skwarnicki, T.; Stone, S.; Wang, J. C.; Bonvicini, G.; Cinabro, D.; Dubrovin, M.; Lincoln, A.; Asner, D. M.; Edwards, K. W.; Naik, P.; Briere, R. A.; Ferguson, T.; Tatishvili, G.; Vogel, H.; Watkins, M. E.; Rosner, J. L.; Adam, N. E.; Alexander, J. P.; Cassel, D. G.; Duboscq, J. E.; Ehrlich, R.; Fields, L.; Gibbons, L.; Gray, R.; Gray, S. W.; Hartill, D. L.; Heltsley, B. K.; Hertz, D.; Jones, C. D.; Kandaswamy, J.; Kreinick, D. L.; Kuznetsov, V. E.; Mahlke-Krüger, H.; Mohapatra, D.; Onyisi, P. U. E.; Patterson, J. R.; Peterson, D.; Pivarski, J.; Riley, D.; Ryd, A.; Sadoff, A. J.; Schwarthoff, H.; Shi, X.; Stroiney, S.; Sun, W. M.; Wilksen, T.; Athar, S. B.; Patel, R.; Yelton, J.; Rubin, P.; Cawlfield, C.; Eisenstein, B. I.; Karliner, I.; Kim, D.; Lowrey, N.; Selen, M.; White, E. J.; Wiss, J.; Mitchell, R. E.; Shepherd, M. R.; Besson, D.

2007-10-01

We examine e+e-→Ds-Ds*+ and Ds*-Ds+ interactions at 4170 MeV using the CLEO-c detector in order to measure the decay constant fDs+. We use the Ds+→ℓ+ν channel, where the ℓ+ designates either a μ+ or a τ+, when the τ+→π+ν¯. Analyzing both modes independently, we determine B(Ds+→μ+ν)=(0.594±0.066±0.031)%, and B(Ds+→τ+ν)=(8.0±1.3±0.4)%. We also analyze them simultaneously to find an effective value of Beff(Ds+→μ+ν)=(0.638±0.059±0.033)% and extract fDs+=274±13±7MeV. Combining with our previous determination of B(D+→μ+ν), we also find the ratio fDs+/fD+=1.23±0.11±0.04. We compare to current theoretical estimates. Finally, we find B(Ds+→e+ν)<1.3×10-4 at 90% confidence level.

Properties of duck meat sausages supplemented with cereal flours.

PubMed

Yang, H S; Ali, M S; Jeong, J Y; Moon, S H; Hwang, Y H; Park, G B; Joo, S T

2009-07-01

Duck meat sausages were prepared using 10% beef fat (FDS) and 10% hydrated cereal flours including rice (RDS), wheat, corn, millet, and barley to replace fat. Control duck sausages (DS) were also prepared only with duck meat and duck meat plus 10% beef fat. Results showed that protein and fat contents significantly decreased and total expressible fluid reduced with the addition of cereal flours in duck sausage batters. The FDS had higher fat content and lower pH compared with others. Duck sausages with 10% supplemented wheat flour showed the lowest cooking loss among sausages and had similar redness and chroma values to FDS and DS. Texture analysis indicated that hardness of duck sausage significantly decreased when cereal flours and beef fat were added. In particular, RDS showed the lowest values for all texture measurements compared with others. Result of moisture absorption capacity suggested that the decrease in hardness in RDS was due to higher moisture retention for rice flour treatment. Sensory evaluation indicated that DS had significantly lower overall acceptability than RDS, due to its off-flavor, whereas RDS had higher overall acceptability than DS.

Validation of an integrated software for the detection of rapid eye movement sleep behavior disorder.

PubMed

Frauscher, Birgit; Gabelia, David; Biermayr, Marlene; Stefani, Ambra; Hackner, Heinz; Mitterling, Thomas; Poewe, Werner; Högl, Birgit

2014-10-01

Rapid eye movement sleep without atonia (RWA) is the polysomnographic hallmark of REM sleep behavior disorder (RBD). To partially overcome the disadvantages of manual RWA scoring, which is time consuming but essential for the accurate diagnosis of RBD, we aimed to validate software specifically developed and integrated with polysomnography for RWA detection against the gold standard of manual RWA quantification. Academic referral center sleep laboratory. Polysomnographic recordings of 20 patients with RBD and 60 healthy volunteers were analyzed. N/A. Motor activity during REM sleep was quantified manually and computer assisted (with and without artifact detection) according to Sleep Innsbruck Barcelona (SINBAR) criteria for the mentalis ("any," phasic, tonic electromyographic [EMG] activity) and the flexor digitorum superficialis (FDS) muscle (phasic EMG activity). Computer-derived indices (with and without artifact correction) for "any," phasic, tonic mentalis EMG activity, phasic FDS EMG activity, and the SINBAR index ("any" mentalis + phasic FDS) correlated well with the manually derived indices (all Spearman rhos 0.66-0.98). In contrast with computerized scoring alone, computerized scoring plus manual artifact correction (median duration 5.4 min) led to a significant reduction of false positives for "any" mentalis (40%), phasic mentalis (40.6%), and the SINBAR index (41.2%). Quantification of tonic mentalis and phasic FDS EMG activity was not influenced by artifact correction. The computer algorithm used here appears to be a promising tool for REM sleep behavior disorder detection in both research and clinical routine. A short check for plausibility of automatic detection should be a basic prerequisite for this and all other available computer algorithms. © 2014 Associated Professional Sleep Societies, LLC.

Very late ischemic complications in flow-diverter stents: a retrospective analysis of a single-center series.

PubMed

Guédon, Alexis; Clarençon, Frédéric; Di Maria, Federico; Rosso, Charlotte; Biondi, Alessandra; Gabrieli, Joseph; Rojas, Patricia; Chiras, Jacques; Sourour, Nader

2016-10-01

OBJECTIVE The authors evaluate the rate and discuss the pathomechanisms of very late (≥ 4-month) ischemic complications after flow-diverter stent (FDS) placement for intracranial aneurysms. METHODS The authors retrospectively reviewed the clinical data of the patients treated at Pitié-Salpêtrière Hospital between January 2010 and September 2014, who underwent FDS placement for intracranial aneurysm. The patients received dual-antiplatelet therapy (clopidogrel and aspirin) 5 days before and 3-6 months after the procedure and then aspirin alone for 6-9 months. An ischemic complication was defined as a sudden focal neurological deficit documented on diffusion-weighted images. RESULTS Eighty-six consecutive patients were included. Three (3.5%) patients treated with the Pipeline embolization device experienced a delayed acute ischemic stroke (2 cases of perforator/side-wall branch infarction and 1 case of thromboembolic stroke) with an average delay of 384 days (4 months, 20 months, and 13 months, respectively). The aneurysm locations were the left superior cerebellar artery, the right anterior choroid artery, and the left internal carotid artery (paraclinoid segment), respectively. The complications occurred after the patients had completed the antiaggregation protocol, except for Patient 1, who was receiving aspirin alone because of a spontaneous hematoma. At the acute phase, no in-stent thromboses were found on digital subtraction angiography. In Patient 2, the treated anterior choroid artery was occluded 20 months after the procedure. In Patient 3, a focal stenosis (approximately 40%) of the distal aspect of the FDS, probably caused by intimal hyperplasia, was seen. CONCLUSIONS Very late ischemic complications after FDS treatment were observed in 3.5% of the cases in the authors' series, some of which occurred as late as more than 1 year after placement.

Selective recruitment of single motor units in human flexor digitorum superficialis muscle during flexion of individual fingers.

PubMed

Butler, T J; Kilbreath, S L; Gorman, R B; Gandevia, S C

2005-08-15

Flexor digitorum superficialis (FDS) is an extrinsic multi-tendoned muscle which flexes the proximal interphalangeal joints of the four fingers. It comprises four digital components, each with a tendon that inserts onto its corresponding finger. To determine the degree to which these digital components can be selectively recruited by volition, we recorded the activity of a single motor unit in one component via an intramuscular electrode while the subject isometrically flexed each of the remaining fingers, one at a time. The finger on which the unit principally acted was defined as the 'test finger' and that which flexed isometrically was the 'active' finger. Activity in 79 units was recorded. Isometric finger flexion forces of 50% maximum voluntary contraction (MVC) activated less than 50% of single units in components of FDS acting on fingers that were not voluntarily flexed. With two exceptions, the median recruitment threshold for all active-test finger combinations involving the index, middle, ring and little finger test units was between 49 and 60% MVC (60% MVC being the value assigned to those not recruited). The exceptions were flexion of the little finger while recording from ring finger units (median: 40% MVC), and vice versa (median: 2% MVC). For all active-test finger combinations, only 35/181 units were activated when the active finger flexed at less than 20% MVC, and the fingers were adjacent for 28 of these. Functionally, to recruit FDS units during grasping and lifting, relatively heavy objects were required, although systematic variation occurred with the width of the object. In conclusion, FDS components can be selectively activated by volition and this may be especially important for grasping at high forces with one or more fingers.

Psychometric properties of Frustration Discomfort Scale in a Turkish sample.

PubMed

Ozer, Bilge Uzun; Demir, Ayhan; Harrington, Neil

2012-08-01

The present study assessed the psychometric properties of the Frustration Discomfort Scale for Turkish college students. The Frustration Discomfort Scale (FDS), Procrastination Assessment Scale-Student, and Rosenberg Self-Esteem Scale were administered to a sample of 171 (98 women, 73 men) Turkish college students. The results of the confirmatory factor analysis yielded fit index values demonstrating viability of the four-dimensional solution as in the original. Findings also revealed that, as predicted, the Discomfort Intolerance subscale of Turkish FDS was most strongly correlated with procrastination. Overall results provided evidence for the factor validity and reliability of the Turkish version of the scale for use in a Turkish population.

A wrist tendon travel assessment of hand movements associated with industrial repetitive activities.

PubMed

Ugbolue, U Chris; Nicol, Alexander C

2012-01-01

To investigate slow and fast paced industrial activity hand repetitive movements associated with carpal tunnel syndrome where movements are evaluated based on finger and wrist tendon travel measurements. Nine healthy subjects were recruited for the study aged between 23 and 33 years. Participants mimicked an industrial repetitive task by performing the following activities: wrist flexion and extension task, palm open and close task; and pinch task. Each task was performed for a period of 5 minutes at a slow (0.33 Hz) and fast (1 Hz) pace for a duration of 3 minutes and 2 minutes respectively. Tendon displacement produced higher flexor digitorum superficialis (FDS) tendon travel when compared to the flexor digitorum profundus (FDP) tendons. The left hand mean (SD) tendon travel for the FDS tendon and FDP tendon were 11108 (5188) mm and 9244 (4328) mm while the right hand mean tendon travel (SD) for the FDS tendon and FDP tendon were 9225 (3441) mm and 7670 (2856) mm respectively. Of the three tasks mimicking an industrial repetitive activity, the wrist flexion and extension task produced the most tendon travel. The findings may be useful to researchers in classifying the level of strenuous activity in relation to tendon travel.

Opening a Window on ICME-driven GCR Modulation in the Inner Solar System

NASA Astrophysics Data System (ADS)

Winslow, Reka M.; Schwadron, Nathan A.; Lugaz, Noé; Guo, Jingnan; Joyce, Colin J.; Jordan, Andrew P.; Wilson, Jody K.; Spence, Harlan E.; Lawrence, David J.; Wimmer-Schweingruber, Robert F.; Mays, M. Leila

2018-04-01

Interplanetary coronal mass ejections (ICMEs) often cause Forbush decreases (Fds) in the flux of galactic cosmic rays (GCRs). We investigate how a single ICME, launched from the Sun on 2014 February 12, affected GCR fluxes at Mercury, Earth, and Mars. We use GCR observations from MESSENGER at Mercury, ACE/LRO at the Earth/Moon, and MSL at Mars. We find that Fds are steeper and deeper closer to the Sun, and that the magnitude of the magnetic field in the ICME magnetic ejecta as well as the “strength” of the ICME sheath both play a large role in modulating the depth of the Fd. Based on our results, we hypothesize that (1) the Fd size decreases exponentially with heliocentric distance, and (2) that two-step Fds are more common closer to the Sun. Both hypotheses will be directly verifiable by the upcoming Parker Solar Probe and Solar Orbiter missions. This investigation provides the first systematic study of the changes in GCR modulation as a function of distance from the Sun using nearly contemporaneous observations at Mercury, Earth/Moon, and Mars, which will be critical for validating our physical understanding of the modulation process throughout the heliosphere.

A comparative study of the Unified System for Orbit Computation and the Flight Design System. [computer programs for mission planning tasks associated with space shuttle

NASA Technical Reports Server (NTRS)

Maag, W.

1977-01-01

The Flight Design System (FDS) and the Unified System for Orbit Computation (USOC) are compared and described in relation to mission planning for the shuttle transportation system (STS). The FDS is designed to meet the requirements of a standardized production tool and the USOC is designed for rapid generation of particular application programs. The main emphasis in USOC is put on adaptability to new types of missions. It is concluded that a software system having a USOC-like structure, adapted to the specific needs of MPAD, would be appropriate to support planning tasks in the area unique to STS missions.

Stable and low diffusive hybrid upwind splitting methods

NASA Technical Reports Server (NTRS)

Coquel, Frederic; Liou, Meng-Sing

1992-01-01

We introduce in this paper a new concept for upwinding: the Hybrid Upwind Splitting (HUS). This original strategy for upwinding is achieved by combining the two previous existing approaches, the Flux Vector (FVS) and Flux Difference Splittings (FDS), while retaining their own interesting features. Indeed, our approach yields upwind methods that share the robustness of FVS schemes in the capture of nonlinear waves and the accuracy of some FDS schemes in the capture of linear waves. We describe here some examples of such HUS methods obtained by hybridizing the Osher approach with FVS schemes. Numerical illustrations are displayed and will prove in particular the relevance of the HUS methods we propose for viscous calculations.

Molecular weight dependence of permselectivity to rat small intestinal blood-lymph barrier for exogenous macromolecules absorbed from lumen.

PubMed

Yoshikawa, H; Takada, K; Muranishi, S

1984-01-01

The permselectivity to the small intestinal blood-lymph barrier for the exogenous macromolecules absorbed from the lumen was investigated using in situ rat closed loop experiment. We chose the fluorescein isothiocyanate-labelled dextran (FD) as macromolecule and lipid-surfactant mixed micelles as an absorption promoter. The mean molecular weights of FDs used were 10500, 17500, 39000 and 64200 (abbreviated: FD10 , 20, 40 and 70). The lymph/plasma ratios of FDs concentrations during 5 h post administration were 0.2-1.2 ( FD10 ), 0.4-1.3 ( FD20 ), 1.3-7.2 ( FD40 ) and 2.6-11.9 ( FD70 ), respectively. The FD40 and FD70 levels in the lymph were significantly higher than those in the plasma. The cumulative amounts (% of the absorbed quantity) of FDs in the lymph from the lumen of the small intestine for 5 h after administration were 0.46% ( FD10 ), 0.51% ( FD20 ), 1.17% ( FD40 ) and 1.89% ( FD70 ), respectively. These findings suggest that the threshold molecular weight of FD for the transfer into the lymphatics with higher level compared to the blood concentration from the lumen across the small intestinal blood-lymph barrier exists between 17500 and 39000.

Study on the ternary mixed ligand complex of palladium(II)-aminophylline-fluorescein sodium by resonance Rayleigh scattering, second-order scattering and frequency doubling scattering spectrum and its analytical application.

PubMed

Chen, Peili; Liu, Shaopu; Liu, Zhongfang; Hu, Xiaoli

2011-01-01

The interaction between palladium(II)-aminophylline and fluorescein sodium was investigated by resonance Rayleigh scattering, second-order scattering and frequency doubling scattering spectrum. In pH 4.4 Britton-Robinson (BR) buffer medium, aminophylline (Ami) reacted with palladium(II) to form chelate cation([Pd(Ami)]2+), which further reacted with fluorescein sodium (FS) to form ternary mixed ligand complex [Pd(Ami)(FS)2]. As a result, resonance Rayleigh scattering (RRS), second-order scattering (SOS) and frequency doubling scattering spectrum (FDS) were enhanced. The maximum scattering wavelengths of [Pd(Ami)(FS)2] were located at 300 nm (RRS), 650 nm (SOS) and 304 nm (FDS). The scattering intensities were proportional to the Ami concentration in a certain range and the detection limits were 7.3 ng mL(-1) (RRS), 32.9 ng mL(-1) (SOS) and 79.1 ng mL(-1) (FDS), respectively. Based on it, the new simple, rapid, and sensitive scattering methods have been proposed to determine Ami in urine and serum samples. Moreover, the formation mechanism of [Pd(Ami)(FS)2] and the reasons for enhancement of RRS were fully discussed. Crown Copyright © 2010. Published by Elsevier B.V. All rights reserved.

Sketching Designs Using the Five Design-Sheet Methodology.

PubMed

Roberts, Jonathan C; Headleand, Chris; Ritsos, Panagiotis D

2016-01-01

Sketching designs has been shown to be a useful way of planning and considering alternative solutions. The use of lo-fidelity prototyping, especially paper-based sketching, can save time, money and converge to better solutions more quickly. However, this design process is often viewed to be too informal. Consequently users do not know how to manage their thoughts and ideas (to first think divergently, to then finally converge on a suitable solution). We present the Five Design Sheet (FdS) methodology. The methodology enables users to create information visualization interfaces through lo-fidelity methods. Users sketch and plan their ideas, helping them express different possibilities, think through these ideas to consider their potential effectiveness as solutions to the task (sheet 1); they create three principle designs (sheets 2,3 and 4); before converging on a final realization design that can then be implemented (sheet 5). In this article, we present (i) a review of the use of sketching as a planning method for visualization and the benefits of sketching, (ii) a detailed description of the Five Design Sheet (FdS) methodology, and (iii) an evaluation of the FdS using the System Usability Scale, along with a case-study of its use in industry and experience of its use in teaching.

Simultaneous Forbush decreases and associated geomagnetic storms during the last three solar cycles

NASA Astrophysics Data System (ADS)

Okpala, K. C.

2013-12-01

Forbush decrease (FD) are observed reduction in galactic cosmic ray (GCR) intensity as measured by ground neutron monitors. FD is associated with increased activity of the sun as reflected in the size of the interplanetary coronal mass ejections passing around the Earth and the corotating regions in the Heliosphere. Since the interplanetary anisotropy evolves itself during a geomagnetic storm in addition to the reconfiguration of external magnetospheric currents, it is expected that changes in transmissivity of cosmic rays of glactic origin will occur during Geomagnetic storms. In this study we examine over one hundred and fifty (150) FD events and associated geomagnetic storms over the last three solar cycles from 1970 to 2003. The negative peaks of the FDs and the Dst coincided for most of the events (~70%). There was good correlation (>0.65) between the FDs and Dst. Fresh evidence of the influence of external magnetospheric currents on the count rates of the neutron monitors stations during periods of Forbush decreases (FDs) is provided. This evidence is observed as sudden increases in the count rates during the main phase of simultaneous FD. The magnitude of the sudden rise in the count rates of Neutron monitors and peak dst correlated well (>0.50) both for high latitude and mid latitude stations.

Large eddy simulation of fire-induced buoyancy driven plume dispersion in an urban street canyon under perpendicular wind flow.

PubMed

Hu, L H; Huo, R; Yang, D

2009-07-15

The dispersion of fire-induced buoyancy driven plume in and above an idealized street canyon of 18 m (width) x 18 m (height) x 40 m (length) with a wind flow perpendicular to its axis was investigated by Fire Dynamics Simulator (FDS), Large Eddy Simulation (LES). Former studies, such as that by Oka [T.R. Oke, Street design and urban canopy layer climate, Energy Build. 11 (1988) 103-113], Gayev and Savory [Y.A. Gayev, E. Savory, Influence of street obstructions on flow processes within street canyons. J. Wind Eng. Ind. Aerodyn. 82 (1999) 89-103], Xie et al. [S. Xie, Y. Zhang, L. Qi, X. Tang, Spatial distribution of traffic-related pollutant concentrations in street canyons. Atmos. Environ. 37 (2003) 3213-3224], Baker et al. [J. Baker, H. L. Walker, X. M. Cai, A study of the dispersion and transport of reactive pollutants in and above street canyons--a large eddy simulation, Atmos. Environ. 38 (2004) 6883-6892] and Baik et al. [J.-J. Baik, Y.-S. Kang, J.-J. Kim, Modeling reactive pollutant dispersion in an urban street canyon, Atmos. Environ. 41 (2007) 934-949], focus on the flow pattern and pollutant dispersion in the street canyon with no buoyancy effect. Results showed that with the increase of the wind flow velocity, the dispersion pattern of a buoyant plume fell into four regimes. When the wind flow velocity increased up to a certain critical level, the buoyancy driven upward rising plume was re-entrained back into the street canyon. This is a dangerous situation as the harmful fire smoke will accumulate to pollute the environment and thus threaten the safety of the people in the street canyon. This critical re-entrainment wind velocity, as an important parameter to be concerned, was further revealed to increase asymptotically with the heat/buoyancy release rate of the fire.

Association between hemodynamic modifications and clinical outcome of intracranial aneurysms treated using flow diverters

NASA Astrophysics Data System (ADS)

Paliwal, Nikhil; Damiano, Robert J.; Davies, Jason M.; Siddiqui, Adnan H.; Meng, Hui

2017-03-01

Treatment of intracranial aneurysms (IAs) has been revolutionized by the advent of endovascular Flow Diverters (FDs), which disrupt blood flow within the aneurysm to induce pro-thrombotic conditions, and serves as a scaffold for endothelial ingrowth and arterial remodeling. Despite good clinical success of FDs, complications like incomplete occlusion and post-treatment rupture leading to subarachnoid hemorrhage have been reported. In silico computational fluid dynamic analysis of the pre- and post-treated geometries of IA patients can shed light on the contrasting blood hemodynamics associated with different clinical outcomes. In this study, we analyzed hemodynamic modifications in 15 IA patients treated using a single FD; 10 IAs were completely occluded (successful) and 5 were partially occluded (unsuccessful) at 12-month follow-up. An in-house virtual stenting workflow was used to recapitulate the clinical intervention on these cases, followed by CFD to obtain pre- and post-treatment hemodynamics. Bulk hemodynamic parameters showed comparable reductions in both groups with average inflow rate and aneurysmal velocity reduction of 40.3% and 52.4% in successful cases, and 34.4% and 49.2% in unsuccessful cases. There was a substantial reduction in localized parameter like vortex coreline length and Energy Loss for successful cases, 38.2% and 42.9% compared to 10.1% and 10.5% for unsuccessful cases. This suggest that for successfully treated IAs, the localized complex blood flow is disrupted more prominently by the FD as compared to unsuccessful cases. These localized hemodynamic parameters can be potentially used in prediction of treatment outcome, thus aiding the clinicians in a priori assessment of different treatment strategies.

Association between hemodynamic modifications and clinical outcome of intracranial aneurysms treated using flow diverters.

PubMed

Paliwal, Nikhil; Damiano, Robert J; Davies, Jason M; Siddiqui, Adnan H; Meng, Hui

2017-02-11

Treatment of intracranial aneurysms (IAs) has been revolutionized by the advent of endovascular Flow Diverters (FDs), which disrupt blood flow within the aneurysm to induce pro-thrombotic conditions, and serves as a scaffold for endothelial ingrowth and arterial remodeling. Despite good clinical success of FDs, complications like incomplete occlusion and post-treatment rupture leading to subarachnoid hemorrhage have been reported. In silico computational fluid dynamic analysis of the pre- and post-treated geometries of IA patients can shed light on the contrasting blood hemodynamics associated with different clinical outcomes. In this study, we analyzed hemodynamic modifications in 15 IA patients treated using a single FD; 10 IAs were completely occluded (successful) and 5 were partially occluded (unsuccessful) at 12-month follow-up. An in-house virtual stenting workflow was used to recapitulate the clinical intervention on these cases, followed by CFD to obtain pre- and post-treatment hemodynamics. Bulk hemodynamic parameters showed comparable reductions in both groups with average inflow rate and aneurysmal velocity reduction of 40.3% and 52.4% in successful cases, and 34.4% and 49.2% in unsuccessful cases. There was a substantial reduction in localized parameter like vortex coreline length and Energy Loss for successful cases, 38.2% and 42.9% compared to 10.1% and 10.5% for unsuccessful cases. This suggest that for successfully treated IAs, the localized complex blood flow is disrupted more prominently by the FD as compared to unsuccessful cases. These localized hemodynamic parameters can be potentially used in prediction of treatment outcome, thus aiding the clinicians in a priori assessment of different treatment strategies.

Equation Chapter 1 Section 1Sequence-To-Conformation Relationships of Disordered Regions Tethered to Folded Domains of Proteins.

PubMed

Mittal, Anuradha; Holehouse, Alex S; Cohan, Megan C; Pappu, Rohit V

2018-05-12

Intrinsically disordered proteins and regions (IDPs / IDRs) are characterized by well-defined sequence-to-conformation relationships (SCRs). These relationships refer to the sequence-specific preferences for average sizes, shapes, residue-specific secondary structure propensities, and amplitudes of multiscale conformational fluctuations. SCRs are discerned from the sequence-specific conformational ensembles of IDPs. A vast majority of IDPs are actually tethered to folded domains (FDs). This raises the question of whether or not SCRs inferred for IDPs are applicable to IDRs tethered to folded domains. Here, we use atomistic simulations based on a well-established forcefield paradigm and an enhanced sampling method to obtain comparative assessments of SCRs for thirteen archetypal IDRs modeled as autonomous units, as C-terminal tails connected to folded domains, and as linkers between pairs of folded domains. Our studies uncover a set of general observations regarding context-independent versus context-dependent SCRs of IDRs. SCRs are minimally perturbed upon tethering to folded domains if the IDRs are deficient in charged residues and for polyampholytic IDRs where the oppositely charged residues within the sequence of the IDR are separated into distinct blocks. In contrast, the interplay between IDRs and tethered folded domains has a significant modulatory effect on SCRs if the IDRs have intermediate fractions of charged residues or if they have sequence-intrinsic conformational preferences for canonical random coils. Our findings suggest that IDRs with context-independent SCRs might be independent evolutionary modules whereas IDRs with context-dependent intrinsic SCRs might co-evolve with the FDs to which they are tethered. Copyright © 2018. Published by Elsevier Ltd.

Cooking with Fire: The Mutagenicity- and PAH-Emission ...

EPA Pesticide Factsheets

Emissions from solid fuels used for cooking cause ~4 million premature deaths per year. Advanced solid-fuel cookstoves are a potential solution, but they should be assessed by appropriate performance indicators, including biological effects. We evaluated two categories of solid-fuel cookstoves for 8 pollutant- and 4 mutagenicity-emission factors, correlated the mutagenicity-emission factors, and compared them to those of other combustion emissions. We burned red oak in a 3-stone fire (TSF), a natural-draft stove (NDS), and a forced-draft stove (FDS); we combusted propane as a liquified petroleum gas control fuel. We determined emission factors based on useful energy (megajoules delivered, MJd) for carbon monoxide, nitrogen oxides (NOx), black carbon, methane, total hydrocarbons, 32 polycyclic aromatic hydrocarbons, PM2.5, levoglucosan (a wood-smoke marker), and mutagenicity in Salmonella. Other than NOx the emission factors per MJd correlated highly among each other (r2 ≥ 0.92); NOx correlated 0.58-0.76 with the other emission factors. Excluding NOx, the NDS and FDS reduced the emission factors on average 68 and 92%, respectively, relative to the TSF. Nonetheless, the mutagenicity-emission factor based on fuel energy used (MJthermal) for the most efficient stove (FDS) was intermediate to that of a large diesel bus engine and a small diesel generator. Both mutagenicity- and pollutant-emission factors may be informative for characterizing cookstove

Processing of electronic waste in a counter current teeter-bed separator.

PubMed

Dey, Sujit Kumar; Ari, Vidyadhar; Das, Avimanyu

2012-09-30

Advanced gravity separation of ground electronic waste (e-waste) in a teeter-bed separator was investigated. It was established that the Floatex Density Seprator (FDS) is a promising device for wet processing of e-waste to recover metal values physically. It was possible to enrich the metal content from 23% in the feed to 37% in the product in a single stage operation using the FDS with over 95% recovery of the metals. A two-stage processing scheme was developed that enriched the metal content further to 48.2%. The influence of the operating variables, namely, teeter water flow rate, bed pressure and feed rate were quantified. Low bed pressures and low teeter water rates produced higher mass yields with poorer product grades. On the contrary, a high bed pressure and high teeter water rate combination led to a lower mass yield but better product quality. A high feed rate introduced en-masse settling leading to higher yield but at a poorer product grade. For an FDS with 230 mm × 230 mm cross section and a height of 530 mm, the process condition with 6.6l pm teeter water rate, 5.27 kPa bed pressure and 82 kg/hr feed rate maximized the yield for a target product grade of 37% metal in a single pass. Copyright © 2012 Elsevier Ltd. All rights reserved.

Determination of thorium (IV) using isophthalaldehyde-tetrapyrrole as probe by resonance light scattering, second-order scattering and frequency-doubling scattering spectra

NASA Astrophysics Data System (ADS)

Wang, Jiao; Xue, Jinhua; Xiao, Xilin; Xu, Li; Jiang, Min; Peng, Pengcheng; Liao, Lifu

2017-12-01

The coordination reaction of thorium (IV) with a ditopic bidentate ligand to form supramolecular polymer was studied by resonance light scattering (RLS) spectra, second-order scattering (SOS) spectra and frequency-doubling scattering (FDS) spectra, respectively. The ditopic bidentate ligand is isophthalaldehyde-tetrapyrrole (IPTP). It was synthesized through a condensation reaction of isophthalaldehyde with pyrrole. The formation of supramolecular polymer results in remarkable intensity enhancements of the three light scattering signals. The maximum scattering wavelengths of RLS, FDS and SOS were 290, 568 and 340 nm, respectively. The reaction was used to establish new light scattering methods for the determination of thorium (IV) by using IPTP as probe. Under optimum conditions, the intensity enhancements of RLS, SOS and FDS were directly proportional to the concentration of thorium (IV) in the ranges of 0.01 to 1.2 μg mL- 1, 0.05 to 1.2 μg mL- 1 and 0.05 to 1.2 μg mL- 1, respectively. The detection limits were 0.003 μg mL- 1, 0.012 μg mL- 1 and 0.021 μg mL- 1, respectively. The methods were suitable for analyzing thorium (IV) in actual samples. The results show acceptable recoveries and precision compared with a reference method.

The phenology of cherry blossom (Prunus yedoensis ``Somei-yoshino'') and the geographic features contributing to its flowering

NASA Astrophysics Data System (ADS)

Ohashi, Yukitaka; Kawakami, Hiroshi; Shigeta, Yoshinori; Ikeda, Hiroshi; Yamamoto, Nobuko

2012-09-01

We investigated relationships between the flowering phenology of Prunus yedoensis "Somei-yoshino" (cherry blossom) and the local temperatures in Japan. Our observations were carried out across the Okayama Plain, which included Okayama City (about 700,000 inhabitants), from the winter of 2008 to the spring of 2009. Local air temperature (AT) and the globe temperature (GT) were recorded at the tree height. The flowering dates (FDs) of P. yedoensis were earliest in the central commercial area (located at the center of the plain), followed by the north residential area (further inland), and finally the south residential area (seaward). The recorded FDs were related to the period-averaged daily maximum/minimum AT and GT, and the phenologically effective AT and GT defined in this study. Of these parameters, the phenologically effective GTs correlated most with the FDs. Since the GT is determined by AT, solar and infrared radiations, and wind speed, our previous result suggests that a combination of these three components surrounding the tree is more important for budding and flowering than is AT alone. The supposition is supported by the flowering of P. yedoensis being the latest at the coastal region of the Okayama Plain where the AT were higher than at the inland region, excluding the urban area; it is probably caused by stronger winds there than at the other sites.

A qualitative evaluation of foundation dentists' and training programme directors' perceptions of clinical audit in general dental practice.

PubMed

Thornley, P; Quinn, A; Elley, K

2015-08-28

This study reports on an investigation into clinical audit (CA) educational and service delivery outcomes in a dental foundation training (DFT) programme. The aim was to investigate CA teaching, learning and practice from the perspective of foundation dentists (FDs) and to record suggestions for improvement. A qualitative research methodology was used. Audio recordings of focus group interviews with FDs were triangulated by an interview with a group of training programme directors (TPDs). The interviews were transcribed and thematically analysed using a 'Framework' approach within Nvivo Data Analysis Software. FDs report considerable learning and behaviour change. However, TPDs have doubts about the long-term effects on service delivery. There can be substantial learning in the clinical, managerial, communication and professionalism domains, and in the development of time management, organisational and team-working skills. Information is provided about use of resources and interaction with teachers and colleagues. CA provides learning opportunities not produced by other educational activities including 'awkward conversations' with team-members in the context of change management and providing feedback. This is relevant when applying the recommendations of the Francis report. This paper should be useful to any dentist conducting audit or team training. Suggestions are made for improvements to resources and support including right touch intervention. Trainers should teach in the 'Goldilocks Zone'.

Full spatial-field visualization of gas temperature in an air micro-glow discharge by calibrated Schlieren photography

NASA Astrophysics Data System (ADS)

Xiong, Qing; Xu, Le; Wang, Xia; Xiong, Lin; Huang, Qinghua; Chen, Qiang; Wang, Jingang; Peng, Wenxiong; Li, Jiarui

2018-03-01

Gas temperature is an important basic parameter for both fundamental research and applications of plasmas. In this work, efforts were made to visualize the full spatial field of gas temperature (T g) in a microdischarge with sharp T g gradients by a method of calibrated Schlieren (CS) photography. Compared to other two typical diagnostic approaches, optical emission spectroscopy (OES) and Rayleigh scattering, the proposed CS method exhibits the ability to capture the whole field of gas temperature using a single Schlieren image, even the discharge is of non-luminous zones like Faraday dark space (FDS). The image shows that the T g field in the studied micro-glow air discharge expands quickly with the increase of discharge currents, especially in the cathode region. The two-dimensional maps of gas temperature display a ‘W-shape’ with sharp gradients in both areas of negative and positive glows, slightly arched distributions in the positive column, and cooling zones in the FDS. The obtained T g fields show similar patterns to that of the discharge luminance. With an increase in discharge currents, more electric energy is dissipated by heating air gas and inducing constriction of the low-temperature FDS. Except in the vicinities of electrode boundaries, due to the interference from optical diffraction, the estimated gas temperature distributions are of acceptable accuracy, confirmed by the approaches of OES and UV Rayleigh scattering.

B- and D-meson decay constants from three-flavor lattice QCD

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

Bazavov, A.; et al.

2012-06-01

We calculate the leptonic decay constants of B_{(s)} and D_{(s)} mesons in lattice QCD using staggered light quarks and Fermilab bottom and charm quarks. We compute the heavy-light meson correlation functions on the MILC asqtad-improved staggered gauge configurations which include the effects of three light dynamical sea quarks. We simulate with several values of the light valence- and sea-quark masses (down to ~m_s/10) and at three lattice spacings (a ~ 0.15, 0.12, and 0.09 fm) and extrapolate to the physical up and down quark masses and the continuum using expressions derived in heavy-light meson staggered chiral perturbation theory. We renormalizemore » the heavy-light axial current using a mostly nonperturbative method such that only a small correction to unity must be computed in lattice perturbation theory and higher-order terms are expected to be small. We obtain f_{B^+} = 196.9(8.9) MeV, f_{B_s} = 242.0(9.5) MeV, f_{D^+} = 218.9(11.3) MeV, f_{D_s} = 260.1(10.8) MeV, and the SU(3) flavor-breaking ratios f_{B_s}/f_{B} = 1.229(26) and f_{D_s}/f_{D} = 1.188(25), where the numbers in parentheses are the total statistical and systematic uncertainties added in quadrature.« less

A comparative study of three different synthesis routes for hydrophilic fluorophore-doped silica nanoparticles

NASA Astrophysics Data System (ADS)

Shahabi, Shakiba; Treccani, Laura; Rezwan, Kurosch

2016-01-01

The synthesis of fluorophore-doped silica nanoparticles (FDS NPs) with two conventional approaches, Stöber and microemulsion, as well as a novel amino acid-catalyzed seeds regrowth technique (ACSRT) is presented. The efficiency of each applied synthesis route toward incorporation of selected hydrophilic fluorophores, including rhodamine B isothiocyanate and fluorescein isothiocyanate, without and with an amine-containing crosslinker, into silica matrix was systematically studied. Our results clearly highlight the advantages of ACSRT to obtain FDS NPs with a remarkable encapsulation efficiency, high quantum yield, and enhanced stability against bleaching and dye leaking due to efficient embedding of the dyes inside silica network even without the amine-containing silane reagent. Moreover, evaluation of photostability of FDNPs internalized in human bone cells demonstrates the merits of ACSRT.

International Space Station Environmental Control and Life Support Emergency Response Verification for Node 1

NASA Technical Reports Server (NTRS)

Williams, David E.

2008-01-01

The International Space Station (ISS) Node 1 Environmental Control and Life Support (ECLS) System is comprised of five subsystems: Atmosphere Control and Supply (ACS), Atmosphere Revitalization (AR), Fire Detection and Suppression (FDS), Temperature and Humidity Control (THC), and Water Recovery and Management (WRM). This paper provides a summary of the Node 1 Emergency Response capability, which includes nominal and off-nominal FDS operation, off nominal ACS operation, and off-nominal THC operation. These subsystems provide the capability to help aid the crew members during an emergency cabin depressurization, a toxic spill, or a fire. The paper will also provide a discussion of the detailed Node 1 ECLS Element Verification methodologies for operation of the Node 1 Emergency Response hardware operations utilized during the Qualification phase.

Large eddy simulation of fine water sprays: comparative analysis of two models and computer codes

NASA Astrophysics Data System (ADS)

Tsoy, A. S.; Snegirev, A. Yu.

2015-09-01

The model and the computer code FDS, albeit widely used in engineering practice to predict fire development, is not sufficiently validated for fire suppression by fine water sprays. In this work, the effect of numerical resolution of the large scale turbulent pulsations on the accuracy of predicted time-averaged spray parameters is evaluated. Comparison of the simulation results obtained with the two versions of the model and code, as well as that of the predicted and measured radial distributions of the liquid flow rate revealed the need to apply monotonic and yet sufficiently accurate discrete approximations of the convective terms. Failure to do so delays jet break-up, otherwise induced by large turbulent eddies, thereby excessively focuses the predicted flow around its axis. The effect of the pressure drop in the spray nozzle is also examined, and its increase has shown to cause only weak increase of the evaporated fraction and vapor concentration despite the significant increase of flow velocity.

Mutagenicity and Pollutant Emission Factors of Solid-Fuel Cookstoves: Comparison with Other Combustion Sources

PubMed Central

Mutlu, Esra; Warren, Sarah H.; Ebersviller, Seth M.; Kooter, Ingeborg M.; Schmid, Judith E.; Dye, Janice A.; Linak, William P.; Gilmour, M. Ian; Jetter, James J.; Higuchi, Mark; DeMarini, David M.

2016-01-01

Background: Emissions from solid fuels used for cooking cause ~4 million premature deaths per year. Advanced solid-fuel cookstoves are a potential solution, but they should be assessed by appropriate performance indicators, including biological effects. Objective: We evaluated two categories of solid-fuel cookstoves for eight pollutant and four mutagenicity emission factors, correlated the mutagenicity emission factors, and compared them to those of other combustion emissions. Methods: We burned red oak in a 3-stone fire (TSF), a natural-draft stove (NDS), and a forced-draft stove (FDS), and we combusted propane as a liquified petroleum gas control fuel. We determined emission factors based on useful energy (megajoules delivered, MJd) for carbon monoxide, nitrogen oxides (NOx), black carbon, methane, total hydrocarbons, 32 polycyclic aromatic hydrocarbons, PM2.5, levoglucosan (a wood-smoke marker), and mutagenicity in Salmonella. Results: With the exception of NOx, the emission factors per MJd were highly correlated (r ≥ 0.97); the correlation for NOx with the other emission factors was 0.58–0.76. Excluding NOx, the NDS and FDS reduced the emission factors an average of 68 and 92%, respectively, relative to the TSF. Nevertheless, the mutagenicity emission factor based on fuel energy used (MJthermal) for the most efficient stove (FDS) was between those of a large diesel bus engine and a small diesel generator. Conclusions: Both mutagenicity and pollutant emission factors may be informative for characterizing cookstove performance. However, mutagenicity emission factors may be especially useful for characterizing potential health effects and should be evaluated in relation to health outcomes in future research. An FDS operated as intended by the manufacturer is safer than a TSF, but without adequate ventilation, it will still result in poor indoor air quality. Citation: Mutlu E, Warren SH, Ebersviller SM, Kooter IM, Schmid JE, Dye JA, Linak WP, Gilmour MI, Jetter JJ, Higuchi M, DeMarini DM. 2016. Mutagenicity and pollutant emission factors of solid-fuel cookstoves: comparison with other combustion sources. Environ Health Perspect 124:974–982; http://dx.doi.org/10.1289/ehp.1509852 PMID:26895221

Global Lightning Response to Forbush Decreases in Short-term

NASA Astrophysics Data System (ADS)

Li, H.; Wu, Q.; Wang, C.

2017-12-01

During the past three decades, particular scientific attention has been drawn to the potential link between solar activities and global climate change. How the sun modulates the climate has always been controversial. There are three relatively widely accepted mechanisms illustrating this process: the total solar irradiance (TSI), the solar ultraviolet radiation (SUR), and the space weather mechanisms. As for space weather mechanism, the sun influences the microphysical process in cloud by modulating the cosmic ray flux and thus changes the cloud cover, which finally affects the earth's radiation balance. Unfortunately, the lack of related observations and some opposite research results make this mechanism rather debatable. In order to provide possible evidence for space weather mechanism, we study the influence of Forbush decreases (FDs) of galactic cosmic ray on global lightning activities, which to some extent represents the basic process of cosmic ray-atmospheric coupling. We use the daily lightning counts from 1998 to 2014 observed by LIS sensor aboard the TRMM satellite. Considering the "diurnal distribution" (occurring more in the afternoon than in the morning) and the "seasonal distribution" (occurring more in summer than in winter) of lightning activities as well as the 49-day precession of TRMM satellite, the daily lightning counts show an intricate periodic fluctuation. We propose a 3-step approach - latitude zone limitation, orbit branch selection and local time normalization - to eliminate it. As for FDs, we select them by checking the hourly neutron counts variation of each month of 17 years obtained from the Oulu Cosmic Ray Station. During the selection, we choose the FDs which are "strong" (decrease more than 6%) and "standard" (strongly decrease in a few hours to one day and gradually recover in about one week) to diminish the meteorological influence and other possible disturbance. For both case study and temporal superposition of several cases, the results illustrate that there is a statistically significant positive correlation between FD and daily lightning count, and the latter reaches its minimum 2-3 days after the former onset. In addition, this response enhances if we only choose the stronger and the more standard FDs. This work has reached the 95% confidence level of Monte Carlo test.

Interpreting high time resolution galactic cosmic ray observations in a diffusive context

NASA Astrophysics Data System (ADS)

Jordan, A.; Spence, H. E.; Blake, J. B.; Shaul, D. A.

2009-12-01

We interpret galactic cosmic ray (GCR) variations near Earth within a diffusive context. The variations occur on time-/size-scales ranging from Forbush decreases (Fds), to substructure embedded within Fds, to smaller amplitude and shorter duration variations during relatively benign interplanetary conditions. We use high time resolution GCR observations from the High Sensitivity Telescope (HIST) on Polar and from the Spectrometer for INTEGRAL (SPI) and also use solar wind plasma and magnetic field observations from ACE and/or Wind. To calculate the coefficient of diffusion, we combine these datasets with a simple convection-diffusion model for relativistic charged particles in a magnetic field. We find reasonable agreement between our and previous estimates of the coefficient. We also show whether changes in the coefficient of diffusion are sufficient to explain the above GCR variations.

Warning signals are under positive frequency-dependent selection in nature

PubMed Central

Chouteau, Mathieu; Arias, Mónica; Joron, Mathieu

2016-01-01

Positive frequency-dependent selection (FDS) is a selection regime where the fitness of a phenotype increases with its frequency, and it is thought to underlie important adaptive strategies resting on signaling and communication. However, whether and how positive FDS truly operates in nature remains unknown, which hampers our understanding of signal diversity. Here, we test for positive FDS operating on the warning color patterns of chemically defended butterflies forming multiple coexisting mimicry assemblages in the Amazon. Using malleable prey models placed in localities showing differences in the relative frequencies of warningly colored prey, we demonstrate that the efficiency of a warning signal increases steadily with its local frequency in the natural community, up to a threshold where protection stabilizes. The shape of this relationship is consistent with the direct effect of the local abundance of each warning signal on the corresponding avoidance knowledge of the local predator community. This relationship, which differs from purifying selection acting on each mimetic pattern, indicates that predator knowledge, integrated over the entire community, is saturated only for the most common warning signals. In contrast, among the well-established warning signals present in local prey assemblages, most are incompletely known to local predators and enjoy incomplete protection. This incomplete predator knowledge should generate strong benefits to life history traits that enhance warning efficiency by increasing the effective frequency of prey visible to predators. Strategies such as gregariousness or niche convergence between comimics may therefore readily evolve through their effects on predator knowledge and warning efficiency. PMID:26858416

Anatomical considerations of fascial release in ulnar nerve transposition: a concept revisited.

PubMed

Mahan, Mark A; Gasco, Jaime; Mokhtee, David B; Brown, Justin M

2015-11-01

Surgical transposition of the ulnar nerve to alleviate entrapment may cause otherwise normal structures to become new sources of nerve compression. Recurrent or persistent neuropathy after anterior transposition is commonly attributable to a new distal compression. The authors sought to clarify the anatomical relationship of the ulnar nerve to the common aponeurosis of the humeral head of the flexor carpi ulnaris (FCU) and flexor digitorum superficialis (FDS) muscles following anterior transposition of the nerve. The intermuscular septa of the proximal forearm were explored in 26 fresh cadaveric specimens. The fibrous septa and common aponeurotic insertions of the flexor-pronator muscle mass were evaluated in relation to the ulnar nerve, with particular attention to the effect of transposition upon the nerve in this region. An intermuscular aponeurosis associated with the FCU and FDS muscles was present in all specimens. Transposition consistently resulted in angulation of the nerve during elbow flexion when this fascial septum was not released. The proximal site at which the nerve began to traverse this fascial structure was found to be an average of 3.9 cm (SD 0.7 cm) from the medial epicondyle. The common aponeurosis encountered between the FDS and FCU muscles represents a potential site of posttransposition entrapment, which may account for a subset of failed anterior transpositions. Exploration of this region with release of this structure is recommended to provide an unconstrained distal course for a transposed ulnar nerve.

'These reforms killed me': doctors' perceptions of family medicine during the transition from communism to capitalism.

PubMed

Czachowski, Slawomir; Pawlikowska, Teresa

2011-08-01

The establishment of family medicine (FM) in Poland following political reform. To describe family doctors' (FD) experiences during the introduction of FM. A qualitative study of 25 FDs in Poland, using thematic analysis of semi-structured interviews. Open-structured narrative-based interviews with five FDs were then used to deepen understanding of the major emergent themes. Fifteen of 25 had a different initial specialization to FM; 10 of 25 overseas work experience. Many doctors were driven by personal circumstances to engage with this new discipline, which provided a better fit with their life circumstances and a chance to escape from hierarchical structures characterizing the old regime. Personal experience of role models helped embrace FM, whereas adherence to ingrained biomedical approaches led to difficulty with exposure to common problems and could facilitate burnout. Shifting relationships in the reformed system caused tensions between primary and secondary care. While relationships with patients and specialists were being renegotiated, the concept of an independent FD practice surfaced. We observed that the most serious problems that the doctors encountered were circumstances related to the former health care system, in contrast to any lack of professional skills. This is a rare qualitative study exploring Polish doctors' perspectives of the health care reform after the collapse of communism in Central and Eastern Europe. This analysis of newly qualified FDs has provided an insight into the authentic experiences, and motivation of grass roots FM pioneers in Poland.

Family's difficulty scale in end-of-life home care: a new measure of the family's difficulties in caring for patients with cancer at the end of life at home from bereaved family's perspective.

PubMed

Ishii, Yoko; Miyashita, Mitsunori; Sato, Kazuki; Ozawa, Taketoshi

2012-02-01

The aim of this study was to develop a tool to measure the family's difficulties in caring for cancer patients at the end of life at home: Family's Difficulty Scale in end-of-life home care (FDS). The draft of the FDS was derived from a pilot interview survey and literature reviews. The questionnaires were sent to 395 bereaved family caregivers whose family members were patients with terminal cancer receiving home service. We obtained 306 responses (response rate, 81%). Factor analysis resulted in 29 items and 8 factors: Burden of Care, Concerns about Home Care Doctor, Balance of Work and Care, Patient's Pain and Condition, Concerns about Visiting Nurse, Concerns about Home Care Service, Relationship between Family Caregivers and their Families, and Funeral Preparations. The cumulative rate of contribution was 71.8%. Cronbach coefficient α for the FDS was 0.73-0.75; the intraclass correlation coefficient in the test-retest examination was 0.75-0.85. Evidence for construct validity was confirmed by convergent and divergent validity. Concurrent validity was confirmed by significant correlations between identified factors and concurrent measures. The validity and reliability of this new instrument were confirmed. This scale should help home care providers to assess and focus on family difficulties and provide individualized care for the family who cares for a patient with terminal cancer at home.

GCR Modulation by Small-Scale Features in the Interplanetary Medium

NASA Astrophysics Data System (ADS)

Jordan, A. P.; Spence, H. E.; Blake, J. B.; Mulligan, T. L.; Shaul, D. N.; Galametz, M.

2007-12-01

In an effort to uncover the properties of structures in the interplanetary medium (IPM) that modulate galactic cosmic rays (GCR) on short time-scales (from hours to days), we study periods of differing conditions in the IPM. We analyze GCR variations from spacecraft both inside and outside the magnetosphere, using the High Sensitivity Telescope (HIST) on Polar and the Spectrometer for INTEGRAL (SPI). We seek causal correlations between the observed GCR modulations and structures in the solar wind plasma and interplanetary magnetic field, as measured concurrently with ACE and/or Wind. Our analysis spans time-/size-scale variations ranging from classic Forbush decreases (Fds), to substructure embedded within Fds, to much smaller amplitude and shorter duration variations observed during comparatively benign interplanetary conditions. We compare and contrast the conditions leading to the range of different GCR responses to modulating structures in the IPM.

International Space Station Environmental Control and Life Support System Acceptance Testing for Node 1 Temperature and Humidity Control Subsystem

NASA Technical Reports Server (NTRS)

Williams, David E.

2011-01-01

The International Space Station (ISS) Node 1 Environmental Control and Life Support (ECLS) System is comprised of five subsystems: Atmosphere Control and Storage (ACS), Atmosphere Revitalization (AR), Fire Detection and Suppression (FDS), Temperature and Humidity Control (THC), and Water Recovery and Management (WRM). This paper will provide a summary of the Node 1 ECLS THC subsystem design and a detailed discussion of the ISS ECLS Acceptance Testing methodology utilized for this subsystem.The International Space Station (ISS) Node 1 Environmental Control and Life Support (ECLS) System is comprised of five subsystems: Atmosphere Control and Storage (ACS), Atmosphere Revitalization (AR), Fire Detection and Suppression (FDS), Temperature and Humidity Control (THC), and Water Recovery and Management (WRM). This paper will provide a summary of the Node 1 ECLS THC subsystem design and a detailed discussion of the ISS ECLS Acceptance Testing methodology utilized for this subsystem.

Analysis of a Smartphone-Based Architecture with Multiple Mobility Sensors for Fall Detection

PubMed Central

Santoyo-Ramón, Jose Antonio; Cano-García, Jose Manuel

2016-01-01

During the last years, many research efforts have been devoted to the definition of Fall Detection Systems (FDSs) that benefit from the inherent computing, communication and sensing capabilities of smartphones. However, employing a smartphone as the unique sensor in a FDS application entails several disadvantages as long as an accurate characterization of the patient’s mobility may force to transport this personal device on an unnatural position. This paper presents a smartphone-based architecture for the automatic detection of falls. The system incorporates a set of small sensing motes that can communicate with the smartphone to help in the fall detection decision. The deployed architecture is systematically evaluated in a testbed with experimental users in order to determine the number and positions of the sensors that optimize the effectiveness of the FDS, as well as to assess the most convenient role of the smartphone in the architecture. PMID:27930736

Analysis of a Smartphone-Based Architecture with Multiple Mobility Sensors for Fall Detection.

PubMed

Casilari, Eduardo; Santoyo-Ramón, Jose Antonio; Cano-García, Jose Manuel

2016-01-01

During the last years, many research efforts have been devoted to the definition of Fall Detection Systems (FDSs) that benefit from the inherent computing, communication and sensing capabilities of smartphones. However, employing a smartphone as the unique sensor in a FDS application entails several disadvantages as long as an accurate characterization of the patient's mobility may force to transport this personal device on an unnatural position. This paper presents a smartphone-based architecture for the automatic detection of falls. The system incorporates a set of small sensing motes that can communicate with the smartphone to help in the fall detection decision. The deployed architecture is systematically evaluated in a testbed with experimental users in order to determine the number and positions of the sensors that optimize the effectiveness of the FDS, as well as to assess the most convenient role of the smartphone in the architecture.

Parenting skills and family support programs for drug-abusing mothers.

PubMed

Kumpfer, Karol L; Fowler, Melissa A

2007-04-01

Children born to drug-using mothers can suffer from fetal alcohol or drug syndrome (FAS/FDS) or fetal alcohol or drug effect (FAE/FDE). Such children have a greater likelihood of developing acute or chronic physical, cognitive and behavioral problems. In-utero exposure to tobacco, alcohol or drugs impact on the developing fetus and, after birth, the family environment and family system exert effects on the infants and children of substance-abusing parents. Evidence-based prevention and maternal drug treatment programs focus on enhancing parental childcaring abilities, supporting parent-child attachment and encouraging family support systems to improve children's health and cognitive outcomes. FAS/FDS prevention programs, as well as selective and indicated prenatal and postnatal interventions, can improve the support given both to mother and to child, and evidence-based, in-home parenting and family-skills-training approaches are particularly useful.

Carbon Dioxide Dispersion in the Combustion Integrated Rack Simulated Numerically

NASA Technical Reports Server (NTRS)

Wu, Ming-Shin; Ruff, Gary A.

2004-01-01

When discharged into an International Space Station (ISS) payload rack, a carbon dioxide (CO2) portable fire extinguisher (PFE) must extinguish a fire by decreasing the oxygen in the rack by 50 percent within 60 sec. The length of time needed for this oxygen reduction throughout the rack and the length of time that the CO2 concentration remains high enough to prevent the fire from reigniting is important when determining the effectiveness of the response and postfire procedures. Furthermore, in the absence of gravity, the local flow velocity can make the difference between a fire that spreads rapidly and one that self-extinguishes after ignition. A numerical simulation of the discharge of CO2 from PFE into the Combustion Integrated Rack (CIR) in microgravity was performed to obtain the local velocity and CO2 concentration. The complicated flow field around the PFE nozzle exits was modeled by sources of equivalent mass and momentum flux at a location downstream of the nozzle. The time for the concentration of CO2 to reach a level that would extinguish a fire anywhere in the rack was determined using the Fire Dynamics Simulator (FDS), a computational fluid dynamics code developed by the National Institute of Standards and Technology specifically to evaluate the development of a fire and smoke transport. The simulation shows that CO2, as well as any smoke and combustion gases produced by a fire, would be discharged into the ISS cabin through the resource utility panel at the bottom of the rack. These simulations will be validated by comparing the results with velocity and CO2 concentration measurements obtained during the fire suppression system verification tests conducted on the CIR in March 2003. Once these numerical simulations are validated, portions of the ISS labs and living areas will be modeled to determine the local flow conditions before, during, and after a fire event. These simulations can yield specific information about how long it takes for smoke and combustion gases produced by a fire to reach a detector location, how large the fire would be when the detector alarms, and the behavior of the fire until it has been extinguished. This new capability could then be used to optimize the location of fire detectors and fire-suppression ports as well as to evaluate the effectiveness of fire suppressants and response strategies. Numerical data collected from these simulations could also be used to develop a virtual reality fire event for crew training and fire safety awareness. This work is funded by NASA's Bioastronautics Initiative, which has the objective of ensuring and enhancing the health, safety, and performance of humans in space. As part of this initiative, the Microgravity Combustion Science Branch at the NASA Glenn Research Center is conducting spacecraft fire safety research to significantly improve fire safety on inhabited spacecraft.

Three-dimensional neutronics optimization of helium-cooled blanket for multi-functional experimental fusion-fission hybrid reactor (FDS-MFX)

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

Jiang, J.; Yuan, B.; Jin, M.

2012-07-01

Three-dimensional neutronics optimization calculations were performed to analyse the parameters of Tritium Breeding Ratio (TBR) and maximum average Power Density (PDmax) in a helium-cooled multi-functional experimental fusion-fission hybrid reactor named FDS (Fusion-Driven hybrid System)-MFX (Multi-Functional experimental) blanket. Three-stage tests will be carried out successively, in which the tritium breeding blanket, uranium-fueled blanket and spent-fuel-fueled blanket will be utilized respectively. In this contribution, the most significant and main goal of the FDS-MFX blanket is to achieve the PDmax of about 100 MW/m3 with self-sustaining tritium (TBR {>=} 1.05) based on the second-stage test with uranium-fueled blanket to check and validate themore » demonstrator reactor blanket relevant technologies based on the viable fusion and fission technologies. Four different enriched uranium materials were taken into account to evaluate PDmax in subcritical blanket: (i) natural uranium, (ii) 3.2% enriched uranium, (iii) 19.75% enriched uranium, and (iv) 64.4% enriched uranium carbide. These calculations and analyses were performed using a home-developed code VisualBUS and Hybrid Evaluated Nuclear Data Library (HENDL). The results showed that the performance of the blanket loaded with 64.4% enriched uranium was the most attractive and it could be promising to effectively obtain tritium self-sufficiency (TBR-1.05) and a high maximum average power density ({approx}100 MW/m{sup 3}) when the blanket was loaded with the mass of {sup 235}U about 1 ton. (authors)« less

Frequency of palmaris longus absence and its association with other anatomical variations in the Egyptian population.

PubMed

Raouf, Hoda Abdel; Kader, Ghada Abdel; Jaradat, Ahmed; Dharap, Amol; Fadel, Raouf; Salem, Abdel Halim

2013-07-01

The palmaris longus (PL) is one of the most variable muscles in the human body. Racial differences in its variation have been documented. Several studies have attempted to correlate PL absence with other anatomical variations. This study was conducted to determine the prevalence of absence of PL, correlate it with gender and body side and to determine its association with other anatomical variations in the Egyptian population. The presence of PL was clinically determined in 386 Egyptians using the standard technique. All subjects were examined for the presence of the flexor digitorum superficialis (FDS) to the fifth finger. Allen's test was done to assess the completeness of the superficial palmar arch (SPA). The overall prevalence of absence of the PL in Egyptian subjects was 50.8%. There was no significant difference in PL absence with regard to the body side but a significant difference was seen as regards gender and when bilateral absence of PL was compared to its unilateral absence. Absence of FDS tendon to the fifth finger was seen in 1.3% subjects. There was no association between the absence of the FDS tendon to the fifth finger and either presence or absence of PL and also between the absence of PL and the incompleteness of SPA in both genders. In conclusion, the prevalence of absence of PL in the Egyptian population represents one of the highest rates of absence to be reported for this muscle, which is significantly different from that in other ethnic groups. Copyright © 2013 Wiley Periodicals, Inc.

Does the gravity orientation of saccular aneurysms influence hemodynamics? An experimental study with and without flow diverter stent.

PubMed

Chodzyński, Kamil J; Eker, Omer F; Vanrossomme, Axel E; de Sousa, Daniel Ribeiro; Coussement, Grégory; Vanhamme, Luc; Dubois, Frank; Bonafé, Alain; Chopard, Bastien; Courbebaisse, Guy; Zouaoui Boudjeltia, Karim

2016-12-08

Most intracranial aneurysms morphologic studies focused on characterization of size, location, aspect ratio, relationship to the surrounding vasculature and hemodynamics. However, the spatial orientation with respect to the gravity direction has not been taken into account although it could trigger various hemodynamic conditions. The present work addresses this possibility. It was divided in two parts: 1) the orientations of 18, 3D time-of-flight MRI (3D TOF MRI), scans of saccular aneurysms were analyzed. This investigation suggested that there was no privileged orientation for cerebral aneurysms. The aneurysms were oriented in the brain as follows: 9 - down, 9 - up; 11 - right, 7 - left; 6 - front, 12 - back. 2) Based on these results, subsidiary in vitro experiments were performed, analyzing the behavior of red blood cells (RBCs) within a silicone model of aneurysm before and after flow diverter stent (FDS) deployment in the parent vessel. These experiments used a test bench that reproduces physiological pulsatile flow conditions for two orientations: an aneurysm sack pointing either up (opposite to gravitational force) and down (along the gravitational force). The results showed that the orientation of an aneurysm significantly affects the intra-aneurysmal RBCs behavior after stenting, and therefore that gravity can affect the intra-aneurysm behavior of RBCs. This suggests that the patient׳s aneurysm orientation could impact the outcome of the FDS treatment. The implementation of this effect in patient-specific numerical and preoperative decision support techniques could contribute to better understand the intrasaccular biological and hemodynamic events induced by FDS. Copyright © 2016 Elsevier Ltd. All rights reserved.

Retrospective Study of 383 Cases of Fibro-Osseous Lesions of the Jaws.

PubMed

Kato, Camila de Nazaré Alves de Oliveira; Nunes, Laiz Fernandes Mendes; Chalub, Loliza Luiz Figueiredo Houri; Etges, Adriana; Silva, Tarcília Aparecida; Mesquita, Ricardo Alves

2018-05-10

The aims of this study were to describe the clinical and radiologic features of 383 fibro-osseous lesions (FOLs) from an oral pathology reference service in Brazil and to compare the findings with previous studies. The hypothesis of the study was that the most common type of FOL would differ from other investigations. We conducted a descriptive and retrospective study with review of the records of the clinical and biopsy services (1990 to 2015). All records of the patients included showed a definitive diagnosis of FOL. The primary outcome variable was the type of FOL, and the predictor variables were gender, age, ethnicity, location, and clinical and radiologic characteristics. Descriptive analyses and χ 2 tests were performed. The P value was set at .05. From the 27,998 records available, 383 showed FOLs, with 187 (48.8%) being cemento-osseous dysplasias (CODs), 103 (26.9%) being fibrous dysplasias (FDs), and 93 (24.3%) being ossifying fibromas (OFs). The mean age of the patients was 38.5 ± 17.5 years. CODs presented a predilection for female gender (n = 314, 82.0%), African descent (n = 134, 71.6%), and the mandible (n = 248, 64.6%). The most common radiologic feature was a mixed radiolucent-radiopaque image (n = 149, 51.7%). FDs and OFs were commonly diagnosed during the first and second decades of life (P < .001), whereas CODs were more frequently diagnosed beyond the third decade (P < .001). Secondary osteomyelitis was more significantly observed in CODs (P < .001) than in FDs and OFs. Swelling was more frequently reported for FDs and OFs than for CODs (P < .001). CODs were the most frequently observed FOLs in this Brazilian population. Female patients, patients of African descent, and patients with mandibular localization were most commonly affected by these conditions. The most common type of FOL differed from that in similar case reports or series from various geographic locations. It is believed that the data source (clinical and/or biopsy services) can directly influence the outcome. Copyright © 2018 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Efficacy and tolerability of treatment with single doses of diethylcarbamazine (DEC) and DEC plus albendazole (ABZ) for three consecutive years in lymphatic filariasis: a field study in India.

PubMed

Kshirsagar, Nilima A; Gogtay, N J; Garg, B S; Deshmukh, P R; Rajgor, D D; Kadam, V S; Thakur, P A; Gupta, A; Ingole, N S; Lazdins-Helds, J K

2017-10-01

Lymphatic filariasis (LF) affects 73 countries, causes morbidity and impedes socioeconomic development. We had found no difference in safety and micro (Mf) and macro filarial action of single-dose diethylcarbamazine (DEC) and DEC + albendazole (ABZ) in an F01 study done in India (year 2000). There was a programmatic need to evaluate safety and efficacy of multiple annual treatments (F02). Subjects (155) from the F01 study, meeting inclusion-exclusion criteria, were enrolled in F02 and treated with further two annual doses of DEC or DEC + ABZ. Efficacy was evaluated for Mf positivity by peripheral smear (PS) and nucleopore (NP) filter, circulating filarial antigen (CFA) and filarial dance sign (FDS) positivity and Mf count at yearly follow-up. Safety was assessed for 5 days after drug administration. Total of 139 subjects evaluated for efficacy (69 DEC and 70 DEC + ABZ group). Mf positivity prevalence declined progressively by 95% (PS), 66% (NP), and 95% (PS) and 86% (NP); CFA positivity prevalence declined by 15% and 9%; FDS by 100% each; Mf count declined by 75.5 and 76.9% with three annual treatment of DEC and DEC + ABZ, respectively. Addition of ABZ did not show any advantage over DEC given as three annual rounds for LF. DEC and DEC + ABZ were well tolerated. There was no correlation between result of CFA and FDS, (both claimed to be indicative of adult worm). Analysis of published studies and our data indicate that macrofilaricidal effect of DEC/DEC + ABZ may be seen in children and not adults, with three or more annual dosing.

Effect of Low-Frequency rTMS and NMES on Subacute Unilateral Hemispheric Stroke With Dysphagia

PubMed Central

Lim, Kil-Byung; Lee, Hong-Jae; Yoo, Jeehyun

2014-01-01

Objective To investigate the effect of low-frequency repetitive transcranial magnetic stimulation (rTMS) and neuromuscular electrical stimulation (NMES) on post-stroke dysphagia. Methods Subacute (<3 months), unilateral hemispheric stroke patients with dysphagia were randomly assigned to the conventional dysphagia therapy (CDT), rTMS, or NMES groups. In rTMS group, rTMS was performed at 100% resting motor threshold with 1 Hz frequency for 20 minutes per session (5 days per week for 2 weeks). In NMES group, electrical stimulation was applied to the anterior neck for 30 minutes per session (5 days per week for 2 weeks). All three groups were given conventional dysphagia therapy for 4 weeks. We evaluated the functional dysphagia scale (FDS), pharyngeal transit time (PTT), the penetration-aspiration scale (PAS), and the American Speech-Language Hearing Association National Outcomes Measurement System (ASHA NOMS) swallowing scale at baseline, after 2 weeks, and after 4 weeks. Results Forty-seven patients completed the study; 15 in the CDT group, 14 in the rTMS group, and 18 in the NMES group. Mean changes in FDS and PAS for liquid during first 2 weeks in the rTMS and NMES groups were significantly higher than those in the CDT group, but no significant differences were found between the rTMS and NMES group. No significant difference in mean changes of FDS and PAS for semi-solid, PTT, and ASHA NOMS was observed among the three groups. Conclusion These results indicated that both low-frequency rTMS and NMES could induce early recovery from dysphagia; therefore, they both could be useful therapeutic options for dysphagic stroke patients. PMID:25379488

Simulation of wind-driven dispersion of fire pollutants in a street canyon using FDS.

PubMed

Pesic, Dusica J; Blagojevic, Milan Dj; Zivkovic, Nenad V

2014-01-01

Air quality in urban areas attracts great attention due to increasing pollutant emissions and their negative effects on human health and environment. Numerous studies, such as those by Mouilleau and Champassith (J Loss Prevent Proc 22(3): 316-323, 2009), Xie et al. (J Hydrodyn 21(1): 108-117, 2009), and Yassin (Environ Sci Pollut Res 20(6): 3975-3988, 2013) focus on the air pollutant dispersion with no buoyancy effect or weak buoyancy effect. A few studies, such as those by Hu et al. (J Hazard Mater 166(1): 394-406, 2009; J Hazard Mater 192(3): 940-948, 2011; J Civ Eng Manag (2013)) focus on the fire-induced dispersion of pollutants with heat buoyancy release rate in the range from 0.5 to 20 MW. However, the air pollution source might very often be concentrated and intensive, as a consequence of the hazardous materials fire. Namely, transportation of fuel through urban areas occurs regularly, because it is often impossible to find alternative supply routes. It is accompanied with the risk of fire accident occurrences. Accident prevention strategies require analysis of the worst scenarios in which fire products jeopardize the exposed population and environment. The aim of this article is to analyze the impact of wind flow on air pollution and human vulnerability to fire products in a street canyon. For simulation of the gasoline tanker truck fire as a result of a multivehicle accident, computational fluid dynamics large eddy simulation method has been used. Numerical results show that the fire products flow vertically upward, without touching the walls of the buildings in the absence of wind. However, when the wind velocity reaches the critical value, the products touch the walls of the buildings on both sides of the street canyon. The concentrations of carbon monoxide and soot decrease, whereas carbon dioxide concentration increases with the rise of height above the street canyon ground level. The longitudinal concentration of the pollutants inside the street increases with the rise of the wind velocity at the roof level of the street canyon.

Flame spread over thick polymethylmethacrylate samples in a simulated and actual microgravity environment

NASA Astrophysics Data System (ADS)

Shah, Tirthesh Jayesh

The NASA Burning and Suppression of Solids-II (BASS II) experiment examines the combustion of different solid materials and material geometries in microgravity. While flames in microgravity are driven by diffusion and weak advection due to crew movements and ventilation, the current NASA spacecraft material selection test method (NASA-STD- 6001 Test 1) is driven by buoyant forces as gravity is present. The overall goal of this project is to understand the burning of intermediate and thick fuels in microgravity, and devise a normal gravity test to apply to future materials. Clear cast polymethylmethacrylate (PMMA) samples 10 cm long by 1 or 2 cm wide with thicknesses ranging from 1-5 mm were investigated. PMMA is the ideal choice since it is widely used and we know its stoichiometric chemistry. Tests included both one sided and two sided burns. Samples are ignited by heating a wire behind the sample. The samples are burned in a flow duct within the Microgravity Science Glovebox (MSG) on the International Space Station (ISS) to ensure true microgravity conditions. The experiment takes place in opposed flow with varying Oxygen concentrations and flow velocities. Flames are recorded on two cameras and later tracked to determine spread rate. Currently we are modeling combustion of PMMA using Fire Dynamics Simulator (FDS 5.5.3) and Smokeview. The entire modelling for BASS-II is done in DNS mode because of the laminar conditions and small domain. In DNS mode the Navier Stokes equations are solved without the Turbulence model. The model employs the same test sample and MSG geometry as the experiment; but in 2D. The experimental data gave upstream velocity at several points using an anemometer. A flow profile for the inlet velocity is obtained using Matlab and input into the model. The flame spread rates obtained after tracking are then compared with the experimental data and the results follow the trends but the spread rates are higher.

Electrospinning of guar gum/corn starch blends

USDA-ARS?s Scientific Manuscript database

In this study, electrospun nanofibers were prepared for the first time from aqueous blends of guar gum (GG) and corn starch with amylose contents of 27.8% (CS28) and 50% (CS50). The fiber morphology and fiber diameter sizes (FDS) were correlated with solution rheology. The spinning solutions were pr...

24 CFR 902.33 - Financial reporting requirements.

Code of Federal Regulations, 2014 CFR

2014-04-01

... financial data to HUD on an annual basis. The financial information must be: (1) Prepared in accordance with...) Submitted electronically in the format prescribed by HUD using the Financial Data Schedule (FDS). (b) Annual... (a) of this section, a PHA shall provide one copy of the completed audit report package and the...

24 CFR 902.33 - Financial reporting requirements.

Code of Federal Regulations, 2013 CFR

2013-04-01

... financial data to HUD on an annual basis. The financial information must be: (1) Prepared in accordance with...) Submitted electronically in the format prescribed by HUD using the Financial Data Schedule (FDS). (b) Annual... (a) of this section, a PHA shall provide one copy of the completed audit report package and the...

24 CFR 902.33 - Financial reporting requirements.

Code of Federal Regulations, 2012 CFR

2012-04-01

... financial data to HUD on an annual basis. The financial information must be: (1) Prepared in accordance with...) Submitted electronically in the format prescribed by HUD using the Financial Data Schedule (FDS). (b) Annual... (a) of this section, a PHA shall provide one copy of the completed audit report package and the...

24 CFR 902.33 - Financial reporting requirements.

Code of Federal Regulations, 2011 CFR

2011-04-01

... financial data to HUD on an annual basis. The financial information must be: (1) Prepared in accordance with...) Submitted electronically in the format prescribed by HUD using the Financial Data Schedule (FDS). (b) Annual... (a) of this section, a PHA shall provide one copy of the completed audit report package and the...

Polymethylmethacrylate combustion in a narrow channel apparatus simulating a microgravity environment

NASA Astrophysics Data System (ADS)

Bornand, Garrett Randall

Fire safety is an important part of engineering when human lives are at stake. From everyday homes to spacecraft that can cost hundreds of millions of dollars. The research in this thesis attempts to provide scientific evidence that the apparatus in question successfully simulates microgravity and can possibly replace NASA's current test method for spacecraft fire safety. Flame spread tests were conducted with thermally thick and thermally thin polymethylmethacrylate (PMMA) samples to study flame spread behavior in response to environmental changes. The tests were conducted using the San Diego State University Narrow Channel Apparatus (SDSU NCA) as well as within the Microgravity Science Glovebox (MSG) on the International Space Station (ISS). The SDSU NCA can suppress buoyant flow in horizontally spreading flames, and is currently being investigated as a possible replacement or complement to NASA's current material flammability test standard for non-metallic solids, NASA-STD-(I)-6001B Test 1. The buoyant suppression attained in the NCA allows tests to be conducted in a simulated microgravity environment-a characteristic that NASA's Test 1 lacks since flames present in Test 1 are driven by buoyant flows. The SDSU NCA allows for tests to be conducted at various opposed flow oxidizer velocities, oxygen percent by volume, and total pressure to mimic various spacecraft and habitat atmospheres. Tests were conducted at 1 atm pressure, thin fuel thickness of 50 and 75 microns, thick fuel thickness ranging from 3 mm to 5.6 mm, opposed oxidizer velocity ranging from 10 to 25 cm/s, and oxygen concentration by volume at 21, 30, and 50 percent. The simulated microgravity flame spread results were then compared to true microgravity experiments including; testing conducted on the International Space Station (ISS) under the Burning and Suppression of Solids (BASS) research, NASA's 5.2 second Drop Tower, and Micro-Gravity Laboratory's (MGLAB) 4.5 second Drop Tower. Data was also compared to results found by Michigan State University's NCA. Flame spread results from the SDSU NCA compare closely to that of the other experimental techniques. Additionally, an infrared camera and species concentration sensors were added to the SDSU NCA and initial results are provided. Fire Dynamics Simulator (FDS) was used to model the combustion of PMMA within the SDSU NCA. Both thin and thick fuel beds were simulated and the numerical results were compared to experimental data. The simulation was then used to determine various results that cannot easily be found with experimentation, including how effectively the NCA simulates microgravity under certain environmental conditions, gas and fuel bed temperatures, heat fluxes, species concentrations, pyrolysis rate, and other various data. The simulation was found to give reasonable results and overall flame spread trends, but could be improved upon with further detailed kinetic parameter studies.

From Foundation to Honours Degree: The Student Experience

ERIC Educational Resources Information Center

Greenbank, Paul

2007-01-01

Purpose: This paper aims to examine how students from foundation degrees (FDs) run at local further education colleges coped (academically and to a lesser extent psychologically) with the transition to a final year honours degree at a university. Design/methodology/approach: This paper is based on the experience of FD graduates who joined the…

Long term spatial and temporal trends in frost day indices in Kansas, USA

USDA-ARS?s Scientific Manuscript database

Frost day indices such as number of frost days (nFDs), frost free days (nFFDs), last spring freeze (LSF), first fall freeze (FFF), and growing-season length (GSL), were calculated using daily minimum air temperature (Tmin) values from 23 centennial weather stations spread across Kansas during four t...

Development of a Competency Framework for Quality Improvement in Family Medicine: A Qualitative Study

ERIC Educational Resources Information Center

Czabanowska, Katarzyna; Klemenc-Ketis, Zalika; Potter, Amanda; Rochfort, Andree; Tomasik, Tomasz; Csiszar, Judit; Van den Bussche, Piet

2012-01-01

Objective: The aim of this study was to develop a comprehensive framework of quality improvement competencies for use in continuing professional development (CPD) and continuing medical education (CME) for European general practice/family medicine physicians (GPs/FDs). Methods: The study was carried out in three phases: literature review,…

Foundation Degrees: A Case for Greater Institutional Autonomy?

ERIC Educational Resources Information Center

Greenbank, Paul

2010-01-01

Foundation Degrees (FDs) were launched in 2000 by the Department for Education and Skills (DfES). One of the key reasons for their introduction was a belief that this new work-based higher education (HE) qualification could help meet employer demand for people with higher technician/associate professional-level skills. According to the Higher…

Students' Perceptions of Foundation Degrees

ERIC Educational Resources Information Center

Ooms, A.; Burke, L. M.; Marks-Maran, D. J.; Webb, M.; Cooper, D.

2012-01-01

In 2008 there were 87,339 people enrolled on foundation degrees (FDs) in the UK (Foundation Degree Forward, 2009), and educational institutions in the UK offered 1700 different foundation degrees in over 25 subjects, with nearly 900 more in development (Action on Access, 2010). In addition, student views are seen to be of importance, as…

Fatigue Damage Spectrum calculation in a Mission Synthesis procedure for Sine-on-Random excitations

NASA Astrophysics Data System (ADS)

Angeli, Andrea; Cornelis, Bram; Troncossi, Marco

2016-09-01

In many real-life environments, certain mechanical and electronic components may be subjected to Sine-on-Random vibrations, i.e. excitations composed of random vibrations superimposed on deterministic (sinusoidal) contributions, in particular sine tones due to some rotating parts of the system (e.g. helicopters, engine-mounted components,...). These components must be designed to withstand the fatigue damage induced by the “composed” vibration environment, and qualification tests are advisable for the most critical ones. In the case of an accelerated qualification test, a proper test tailoring which starts from the real environment (measured vibration signals) and which preserves not only the accumulated fatigue damage but also the “nature” of the excitation (i.e. sinusoidal components plus random process) is important to obtain reliable results. In this paper, the classic time domain approach is taken as a reference for the comparison of different methods for the Fatigue Damage Spectrum (FDS) calculation in case of Sine-on-Random vibration environments. Then, a methodology to compute a Sine-on-Random specification based on a mission FDS is proposed.

Safety and efficiency of flow diverters for treating small intracranial aneurysms: A systematic review and meta-analysis.

PubMed

Yao, Xiyang; Ma, Junwei; Li, Haiying; Shen, Haitao; Lu, Xiaojun; Chen, Gang

2017-02-01

Background We evaluated the safety and efficiency of flow diverters (FDs) in treating small intracranial aneurysms (IAs). Materials and Methods We reviewed the literature published in PubMed and EMBASE. R for Project software was used to calculate the complete aneurysm occlusion rates, procedure-related neurologic mortality, procedure-related neurologic morbidity and procedure-related permanent morbidity. Results Ten observational studies were included in this analysis. The complete aneurysm occlusion rate was 84.23% (80.34%-87.76%), the procedure-related neurologic mortality was 0.87% (0.29%-1.74%), the procedure-related neurologic morbidity rate was 5.22% (3.62%-7.1%), the intracerebral haemorrhage rate was 1.42% (0.64%-2.49%), the ischemic rate was 2.35% (1.31%-3.68%), the subarachnoid haemorrhage rate was 0.03% (0%-0.32%) and the procedure-related permanent morbidity was 2.41% (0.81%-4.83%). Conclusions Treatment of small IAs with FDs may be correlated with high complete occlusion rates and low complication rates. Future long-term follow-up randomized trials will determine the optimal treatment for small IAs.

Two-Dimensional Fluorescence Difference Spectroscopy of ZnO and Mg Composites in the Detection of Physiological Protein and RNA Interactions

PubMed Central

Hoffman, Amanda; Wu, Xiaotong; Wang, Jianjie; Brodeur, Amanda; Thomas, Rintu; Thakkar, Ravindra; Hadi, Halena; Glaspell, Garry P.; Duszynski, Molly; Wanekaya, Adam; DeLong, Robert K.

2017-01-01

Two-dimensional fluorescence difference spectroscopy (2-D FDS) was used to determine the unique spectral signatures of zinc oxide (ZnO), magnesium oxide (MgO), and 5% magnesium zinc oxide nanocomposite (5% Mg/ZnO) and was then used to demonstrate the change in spectral signature that occurs when physiologically important proteins, such as angiotensin-converting enzyme (ACE) and ribonuclease A (RNase A), interact with ZnO nanoparticles (NPs). When RNase A is bound to 5% Mg/ZnO, the intensity is quenched, while the intensity is magnified and a significant shift is seen when torula yeast RNA (TYRNA) is bound to RNase A and 5% Mg/ZnO. The intensity of 5% Mg/ZnO is quenched also when thrombin and thrombin aptamer are bound to the nanocomposite. These data indicate that RNA–protein interaction can occur unimpeded on the surface of NPs, which was confirmed by gel electrophoresis, and importantly that the change in fluorescence excitation, emission, and intensity shown by 2-D FDS may indicate specificity of biomolecular interactions. PMID:29244716

Study on the interaction between albendazole and eosin Y by fluorescence, resonance Rayleigh scattering and frequency doubling scattering spectra and their analytical applications

NASA Astrophysics Data System (ADS)

Tian, Fengling; Huang, Wei; Yang, Jidong; Li, Qin

In pH 3.25-3.35 Britton-Robinson (BR) buffer solution, albendazole (ABZ) could react with eosin Y (EY) to form a 1:1 ion-association complex, which not only results in the quenching of fluorescence, but also resulted in the great enhancement of resonance Rayleigh scattering (RRS) and frequency doubling scattering (FDS). Furthermore, a new RRS spectrum will appear, and the maximum RRS wavelength was located at about 356 nm. The detection limit for ABZ were 21.51 ng mL-1 for the fluorophotometry, 6.93 ng mL-1 for the RRS method and 12.89 ng mL-1 for the FDS method. Among them, the RRS method had the highest sensitivity. The experimental conditions were optimized and effects of coexisting substances were evaluated. Meanwhile, the influences of coexisting substances were tested. The methods have been successfully applied to the determination of ABZ in capsules and human urine samples. The composition and structure of the ion-association complex and the reaction mechanism were discussed.

Reader Architectures for Wireless Surface Acoustic Wave Sensors.

PubMed

Lurz, Fabian; Ostertag, Thomas; Scheiner, Benedict; Weigel, Robert; Koelpin, Alexander

2018-05-28

Wireless surface acoustic wave (SAW) sensors have some unique features that make them promising for industrial metrology. Their decisive advantage lies in their purely passive operation and the wireless readout capability allowing the installation also at particularly inaccessible locations. Furthermore, they are small, low-cost and rugged components on highly stable substrate materials and thus particularly suited for harsh environments. Nevertheless, a sensor itself does not carry out any measurement but always requires a suitable excitation and interrogation circuit: a reader. A variety of different architectures have been presented and investigated up to now. This review paper gives a comprehensive survey of the present state of reader architectures such as time domain sampling (TDS), frequency domain sampling (FDS) and hybrid concepts for both SAW resonators and reflective SAW delay line sensors. Furthermore, critical performance parameters such as measurement accuracy, dynamic range, update rate, and hardware costs of the state of the art in science and industry are presented, compared and discussed.

A dual spectroscopic fluorescence probe based on carbon dots for detection of 2,4,6-trinitrophenol/Fe (III) ion by fluorescence and frequency doubling scattering spectra and its analytical applications.

PubMed

Xu, Jinxia; Bai, Zhangjun; Zu, Fanlin; Yan, Fanyong; Wei, Junfu; Zhang, Saihui; Luo, Yunmei

2018-07-05

A convenient, highly sensitive and reliable assay for 2,4,6‑trinitrophenol (TNP) and Fe (III) ion (Fe 3+ ) in the dual spectroscopic manner is developed based on novel carbon dots (CDs). The CDs with highly blue emitting fluorescent were easily prepared via the one-step potassium hydroxide-assisted reflux method from dextrin. The as-synthesized CDs exhibited the high crystalline quality, the excellent fluorescence characteristics with a high quantum yield of ~13.1%, and the narrow size distribution with an average diameter of 6.3±0.5nm. Fluorescence and frequency doubling scattering (FDS) spectra of CDs show the unique changes in the presence of TNP/Fe 3+ by different mechanism. The fluorescence of CDs decreased apparently in the presence of TNP via electron-transfer. Thus, after the experimental conditions were optimized, the linear range for detection TNP is 0-50μM, the detection limit was 19.1nM. With the addition of Fe 3+ , the FDS of CDs appeared to be highly sensitive with a quick response to Fe 3+ as a result of the change concentration of the scattering particle. The emission peak for FDS at 450nm was enhanced under the excitation wavelength at 900nm. The fluorescence response changes linearly with Fe 3+ concentration in the range of 8-40μM, the detection limits were determined to be 44.1nM. The applications of CDs were extended for the detection of TNP, Fe 3+ in real water samples with a high recovery. The results reported here may become the potential tools for the fast response of TNP and Fe 3+ in the analysis of environmental pollutants. Copyright © 2018 Elsevier B.V. All rights reserved.

Scale-free crystallization of two-dimensional complex plasmas: Domain analysis using Minkowski tensors

NASA Astrophysics Data System (ADS)

Böbel, A.; Knapek, C. A.; Räth, C.

2018-05-01

Experiments of the recrystallization processes in two-dimensional complex plasmas are analyzed to rigorously test a recently developed scale-free phase transition theory. The "fractal-domain-structure" (FDS) theory is based on the kinetic theory of Frenkel. It assumes the formation of homogeneous domains, separated by defect lines, during crystallization and a fractal relationship between domain area and boundary length. For the defect number fraction and system energy a scale-free power-law relation is predicted. The long-range scaling behavior of the bond-order correlation function shows clearly that the complex plasma phase transitions are not of the Kosterlitz, Thouless, Halperin, Nelson, and Young type. Previous preliminary results obtained by counting the number of dislocations and applying a bond-order metric for structural analysis are reproduced. These findings are supplemented by extending the use of the bond-order metric to measure the defect number fraction and furthermore applying state-of-the-art analysis methods, allowing a systematic testing of the FDS theory with unprecedented scrutiny: A morphological analysis of lattice structure is performed via Minkowski tensor methods. Minkowski tensors form a complete family of additive, motion covariant and continuous morphological measures that are sensitive to nonlinear properties. The FDS theory is rigorously confirmed and predictions of the theory are reproduced extremely well. The predicted scale-free power-law relation between defect fraction number and system energy is verified for one more order of magnitude at high energies compared to the inherently discontinuous bond-order metric. It is found that the fractal relation between crystalline domain area and circumference is independent of the experiment, the particular Minkowski tensor method, and the particular choice of parameters. Thus, the fractal relationship seems to be inherent to two-dimensional phase transitions in complex plasmas. Minkowski tensor analysis turns out to be a powerful tool for investigations of crystallization processes. It is capable of revealing nonlinear local topological properties, however, still provides easily interpretable results founded on a solid mathematical framework.

Diagnostic Value of Isolated Mentalis Versus Mentalis Plus Upper Limb Electromyography in Idiopathic REM Sleep Behavior Disorder Patients Eventually Developing a Neurodegenerative Syndrome.

PubMed

Fernández-Arcos, Ana; Iranzo, Alex; Serradell, Mónica; Gaig, Carles; Guaita, Marc; Salamero, Manel; Santamaria, Joan

2017-04-01

To compare two electromyographic (EMG) montages, isolated mentalis muscle versus mentalis in combination with upper limb muscles in the baseline diagnostic video-polysomnography (V-PSG) of patients with idiopathic REM sleep behaviors disorder (IRBD) who eventually were diagnosed with a clinically defined neurodegenerative syndrome. Forty-nine patients were included. At baseline, diagnosis of RBD was based on a typical history of dream enactment behaviors plus V-PSG showing REM sleep with qualitative increased EMG activity and/or abnormal behaviors. Quantification of EMG activity (tonic, phasic and "any") in the mentalis and upper limb muscles (biceps brachii-BB, n = 36 or flexor digitorum superficialis-FDS, n = 13) was performed manually and compared with published cut-offs. Nine (18.4%) patients had either tonic or phasic EMG below the cut-offs for the isolated mentalis and four of them (11.1 %) also had values below the cut-off for the mentalis combined with BB. All 13 patients recorded with the FDS were above the mentalis combined with FDS cut-off. For the diagnosis of IRBD, sensitivity of isolated mentalis was 81.6% and of the combination of mentalis plus upper limb muscles was 91.8% (p = .03). Audiovisual analysis showed abnormal REM sleep behaviors in all nine patients with values below the cut-offs. Quantification of EMG activity in the upper limbs combined with the mentalis increases the ability to diagnose IRBD when compared with the isolated measurement of the mentalis. Detection of typical abnormal behaviors during REM sleep with audiovisual analysis is essential for the diagnosis of IRBD in patients with EMG values below the published cut-offs. © Sleep Research Society 2017. Published by Oxford University Press on behalf of the Sleep Research Society. All rights reserved. For permissions, please e-mail journals.permissions@oup.com.

Primary Motor Cortex Representation of Handgrip Muscles in Patients with Leprosy

PubMed Central

Rangel, Maria Luíza Sales; Sanchez, Tiago Arruda; Moreira, Filipe Azaline; Hoefle, Sebastian; Souto, Inaiacy Bittencourt; da Cunha, Antônio José Ledo Alves

2015-01-01

Background Leprosy is an endemic infectious disease caused by Mycobacterium leprae that predominantly attacks the skin and peripheral nerves, leading to progressive impairment of motor, sensory and autonomic function. Little is known about how this peripheral neuropathy affects corticospinal excitability of handgrip muscles. Our purpose was to explore the motor cortex organization after progressive peripheral nerve injury and upper-limb dysfunction induced by leprosy using noninvasive transcranial magnetic stimulation (TMS). Methods In a cross-sectional study design, we mapped bilaterally in the primary motor cortex (M1) the representations of the hand flexor digitorum superficialis (FDS), as well as of the intrinsic hand muscles abductor pollicis brevis (APB), first dorsal interosseous (FDI) and abductor digiti minimi (ADM). All participants underwent clinical assessment, handgrip dynamometry and motor and sensory nerve conduction exams 30 days before mapping. Wilcoxon signed rank and Mann-Whitney tests were performed with an alpha-value of p<0.05. Findings Dynamometry performance of the patients’ most affected hand (MAH), was worse than that of the less affected hand (LAH) and of healthy controls participants (p = 0.031), confirming handgrip impairment. Motor threshold (MT) of the FDS muscle was higher in both hemispheres in patients as compared to controls, and lower in the hemisphere contralateral to the MAH when compared to that of the LAH. Moreover, motor evoked potential (MEP) amplitudes collected in the FDS of the MAH were higher in comparison to those of controls. Strikingly, MEPs in the intrinsic hand muscle FDI had lower amplitudes in the hemisphere contralateral to MAH as compared to those of the LAH and the control group. Taken together, these results are suggestive of a more robust representation of an extrinsic hand flexor and impaired intrinsic hand muscle function in the hemisphere contralateral to the MAH due to leprosy. Conclusion Decreased sensory-motor function induced by leprosy affects handgrip muscle representation in M1. PMID:26203653

Students' Perceptions of Undertaking Workplace Tasks within a Foundation Degree--Health and Social Care

ERIC Educational Resources Information Center

Thurgate, Claire; MacGregor, Janet

2009-01-01

Foundation degrees (FDs) involve the fusion of academic and vocational paths in higher education (HE) qualifications; the challenge for academics and employers is the credible assessment of the student's workplace learning. Focusing to the workplace enables participants to learn from their daily routines encountered at work. The challenge is to…

Fourier Descriptor Analysis and Unification of Voice Range Profile Contours: Method and Applications

ERIC Educational Resources Information Center

Pabon, Peter; Ternstrom, Sten; Lamarche, Anick

2011-01-01

Purpose: To describe a method for unified description, statistical modeling, and comparison of voice range profile (VRP) contours, even from diverse sources. Method: A morphologic modeling technique, which is based on Fourier descriptors (FDs), is applied to the VRP contour. The technique, which essentially involves resampling of the curve of the…

Foundation Degrees in Geography and Tourism: A Critical Reflection on Student Experiences and the Implications for Undergraduate Degree Courses

ERIC Educational Resources Information Center

Simm, David; Marvell, Alan; Schaaf, Rebecca; Winlow, Heather

2012-01-01

Over the last decade, some UK Geography Departments have diversified their range of courses to offer Foundation degrees (Fds), providing students with alternative routes through higher education (HE). These courses are delivered either offsite at further education colleges (FECs), embedded within an undergraduate programme at higher education…

Masses and decay constants of D(s) * and B(s) * mesons with Nf=2 +1 +1 twisted mass fermions

NASA Astrophysics Data System (ADS)

Lubicz, V.; Melis, A.; Simula, S.; ETM Collaboration

2017-08-01

We present a lattice calculation of the masses and decay constants of D(s) * and B(s) * mesons using the gauge configurations produced by the European Twisted Mass Collaboration (ETMC) with Nf=2 +1 +1 dynamical quarks at three values of the lattice spacing a ˜(0.06 -0.09 ) fm . Pion masses are simulated in the range Mπ≃(210 - 450 ) MeV , while the strange and charm sea-quark masses are close to their physical values. We compute the ratios of vector to pseudoscalar masses and decay constants for various values of the heavy-quark mass mh in the range 0.7 mcphys≲mh≲3 mcphys . In order to reach the physical b -quark mass, we exploit the heavy quark effective theory prediction that, in the static limit of infinite heavy-quark mass, the considered ratios are equal to one. At the physical point our results are MD*/MD=1.0769 (79 ) , MDs*/MDs=1.0751(56 ), fD*/fD=1.078 (36 ), fDs*/fD s=1.087 (20 ), MB*/MB=1.0078 (15 ), MBs*/MBs=1.0083(10 ), fB*/fB=0.958 (22 ) and fBs*/fB s=0.974 (10 ). Combining them with the experimental values of the pseudoscalar meson masses (used as input to fix the quark masses) and the values of the pseudoscalar decay constants calculated by ETMC, we get MD*=2013 (14 ), MDs*=2116 (11 ), fD*=223.5 (8.4 ), fDs*=268.8 (6.6 ), MB*=5320.5 (7.6 ), MBs*=5411.36 (5.3 ), fB*=185.9 (7.2 ) and fBs*=223.1 (5.4 ) MeV .

Towards a Pedagogy of Work-Based Learning: Perceptions of Work-Based Learning in Foundation Degrees

ERIC Educational Resources Information Center

Burke, Linda; Marks-Maran, Diane J.; Ooms, Ann; Webb, Marion; Cooper, Denise

2009-01-01

One of the features of foundation degrees (FDs) is the incorporation of work-based learning (WBL) into the curriculum. WBL is seen as an important part of vocational programmes and is described by Foundation Degrees Forward (FDF) as a potentially radical approach to connecting work with learning. The Quality Assurance Agency (QAA), in its…

Fire Support Team Experiment.

DTIC Science & Technology

1984-12-01

December 1984 APPROVED FOR PUBUC RELEASE; DISTRIBUTION UNLIMITED. U_ US ARMY *’ HUMAN ENGINEERING LABORATORY US ARMY BALLISTIC RESEARCH LABORATORY ABERDEEN...INTRODUCTION A. Background In March 1982, the HELBAT ( Human Engineering Laboratory Battalion Artillery Test) Executive Committee agreed that the Ballistic...tactical equipment and its -. human operators. FOSCE mimicked the actions of the platoon forward observers that work for the FIST HQ while the FDS

Vortex-antivortex lattices in superconducting films with arrays of magnetic dots

NASA Astrophysics Data System (ADS)

Milosevic, M. V.; Peeters, F. M.

2004-03-01

Using the numerical approach within the phenomenological Ginzburg-Landau (GL) theory, we investigate the vortex structure of a thin superconducting film (SC) with a regular matrix of out-of-plane magnetized ferromagnetic dots (FD) deposited on top of it. The perturbation of the superconducting order parameter in the SC film as subject of the inhomogeneous magnetic field of the FDs is studied, and various vortex-antivortex configurations are observed, with net vorticity equal zero. In the case of a periodic array of magnetic disks, vortices are confined under the disks, while the antivortices form a rich spectra of lattice states. In the ground state, antivortices are arranged in the so-called matching configurations between the FDs, while other configurational varieties have higher energy. In the metastable regime, the states with fractional number of vortex-antivortex pairs per unit cell are found, some of which with strongly distorted vortex cores. The exact (anti)vortex structure depends on the size, thickness and magnetization of the magnetic dots, periodicity of the FD-rooster and the properties of the SC expressed through the effective Ginzburg-Landau parameter κ ^* . We discuss the further experimental implications, such as magnetic-field-induced superconductivity.

Fourier descriptor analysis and unification of voice range profile contours: method and applications.

PubMed

Pabon, Peter; Ternström, Sten; Lamarche, Anick

2011-06-01

To describe a method for unified description, statistical modeling, and comparison of voice range profile (VRP) contours, even from diverse sources. A morphologic modeling technique, which is based on Fourier descriptors (FDs), is applied to the VRP contour. The technique, which essentially involves resampling of the curve of the contour, is assessed and also is compared to density-based VRP averaging methods that use the overlap count. VRP contours can be usefully described and compared using FDs. The method also permits the visualization of the local covariation along the contour average. For example, the FD-based analysis shows that the population variance for ensembles of VRP contours is usually smallest at the upper left part of the VRP. To illustrate the method's advantages and possible further application, graphs are given that compare the averaged contours from different authors and recording devices--for normal, trained, and untrained male and female voices as well as for child voices. The proposed technique allows any VRP shape to be brought to the same uniform base. On this uniform base, VRP contours or contour elements coming from a variety of sources may be placed within the same graph for comparison and for statistical analysis.

Two Dimensional Heat Transfer in Non-Thermally Thin Poly(Methyl Methacrylate) During Combustion in a Narrow Channel Apparatus

NASA Astrophysics Data System (ADS)

Lage, Nicholas Alexander

Experimentation and Computational modeling of non-thermally thin samples of poly(methyl methacrylate) (PMMA) burning in a Narrow Channel Apparatus (NCA) was conducted. The Narrow Channel Apparatus is used to replicate a microgravity environment by flowing of mixtures of nitrogen and oxygen through a narrow gap to suppress buoyancy above the burning sample. A new NCA was built, and experiments were conducted using it to provide the empirical data presented in this thesis. Samples of PMMA were burned, with thicknesses of 3, 5, and 10 mm, with an opposed-flow mean velocity of 15 cm/s and a 21% oxygen concentration. Flame spread rates were obtained from tracked flame positions. Thermocouples were embedded in the top and bottom surfaces of some of the samples to measure surface temperatures. Using Fire Dynamics Simulator (FDS), version 6.2.0, coupled with Gpyro, a two-dimensional model was developed for non-thermally thin samples of PMMA that are burned in the NCA. A 5 mm gap height was used as well as a laminar, parabolic flow at the inlet. Direct numerical simulation (DNS) was set. Finite rate kinetics were used to model the pyrolysis and combustion reactions. Complete combustion was assumed. Simulations with fuel thicknesses of 1, 3, 5, and 10 mm were run, under the same conditions as the experiment. A comparison between one-dimensional and two-dimensional heat conduction within the sample was made to show the effect the heat transfer parallel to flame propagation has on flame spread rates and solid-phase temperature profiles. A comparison between mica and an adiabatic plane set beneath the PMMA was also made as well as the length of time the sample is exposed to the ignition source. Through comparison of the model with the experiment, it was found that the flame spread rates of the model showed unrealistic trends with thickness. An investigation was completed with the aid of an energy balance as well as graphs, such as equivalence ratios, surface temperatures, surface heat fluxes, fuel vapor mass fluxes, etc., that were plotted with respect to the flame position to find the source of the unrealistic trends, but conclusive evidence was never obtained.

How Does the Political Nature of the Defense Acquisition Process Affect Cost Growth

DTIC Science & Technology

2006-09-01

using the following equations. 100*% k k k BCWP COCO = (5) Where: k = the kth year of DAES reporting and, kKk BCWPACWPCO −= (6) The...F-16 270 F-35 Joint Strike Fighter (JSF) 6 FAAD C2I 64 FAAD NLOS Fiber Optic Guided-Missile 7 FBCB2 19 FDS 60 FFG-7 271 Future Aircraft Carrier

Geological, geochemical and isotope diversity of 134 Ma dykes from the Florianópolis Dyke Swarm, Paraná Magmatic Province: Geodynamic controls on petrogenesis

NASA Astrophysics Data System (ADS)

Florisbal, L. M.; Janasi, V. A.; Bitencourt, M. F.; Nardi, L. V. S.; Marteleto, N. S.

2018-04-01

The Florianópolis Dyke Swarm (FDS), one of the major dyke swarms belonging to the Early cretaceous (135-131 Ma) Paraná Magmatic Province, is largely dominated by high Sr-Ti-P basalts that are confirmed here as feeders of the unique Urubici (= Khumib) lavas of the Paraná and Edendeka lava piles on the basis of their age and geochemistry. Our study integrates field, petrographic, whole-rock geochemistry, and Sr-Nd-Pb isotope geochemistry of representative samples from three main areas of exposition (Santa Catarina Island, Garopaba and Pinheira beaches), thus encompassing the whole extension of the FDS. Compared to the Urubici lavas, the dykes have usually higher contents of LILE and LREE, more radiogenic Sr and Pb, and more unradiogenic Nd, features attributed to a more pronounced interaction with melts derived from the country rocks registered in the basic magmas that remained in the conduits. Some of these dykes show strongly interactive contacts that must be part of a wider zone of crustal melting, probably more developed at greater depths. Small volumes of intermediate to acidic rocks form the cores of some composite dykes, and correspond to products of fractional crystallization from Urubici basalts contaminated with high Rb/Sr, and U/Th crustal melts (probably derived from Neoproterozoic granites), as indicated by geochemical and Sr-Nd-Pb isotope data. The chemical and isotope signatures of the less contaminated FDS basalts and related Urubici lavas do not show clear evidence of inputs from primitive mantle, and seem heavily influenced by enriched mantle. This suggests that the mantle wedge that was affected by subduction during the Neoproterozoic may have been frozen and coupled to the base of the lithospheric plate where the Early cretaceous magmatism occurred. A control of previous tectonic limits on the sources of the Urubici basalts seems evident, since they seem to be related to the younger lithosphere from the South Domain, related to the Florianópolis Batholith, and no influence from the older "cratonic" lithosphere of the Central Domain can be identified in their feeders.

Effect of Electrical Stimulation of the Suprahyoid Muscles in Brain-Injured Patients with Dysphagia.

PubMed

Beom, Jaewon; Oh, Byung-Mo; Choi, Kyoung Hyo; Kim, Won; Song, Young Jin; You, Dae Sang; Kim, Sang Jun; Han, Tai Ryoon

2015-08-01

The purpose of this study is to determine whether neuromuscular electrical stimulation of the suprahyoid muscle is effective compared to that of the infrahyoid muscle in brain-injured patients with dysphagia. A total of 132 patients with stroke, traumatic brain injury, or brain tumor in 2 university hospitals were allocated to 2 groups: those who received electrical stimulation therapy (EST) on the suprahyoid muscles (SM group, n = 66) and those who received EST with one pair of electrodes on the suprahyoid muscle and the other pair on the infrahyoid muscle (SI group, n = 66). Patients received 11.2 ± 3.4 sessions of electrical stimulation in the SM group and 11.9 ± 3.4 sessions in the SI group. The functional dysphagia scale (FDS), swallow function score (SFS), supraglottic penetration, and subglottic aspiration were measured using videofluoroscopic swallowing study. FDS scores decreased from 42.0 ± 19.1 to 32.3 ± 17.8 in the SM group and from 44.8 ± 17.4 to 32.9 ± 18.8 in the SI group by per-protocol (PP) analysis, and those decreased from 41.2 ± 20.9 to 34.5 ± 20.3 in the SM group and from 44.3 ± 19.1 to 35.7 ± 20.5 in the SI group by intention-to-treat (ITT) analysis, after electrical stimulation (p < 0.001 for each). SFSs increased from 3.3 ± 1.8 to 4.2 ± 1.6 in the SM group and from 2.8 ± 1.8 to 4.0 ± 1.8 in the SI group by PP analysis, and those increased from 3.3 ± 1.6 to 3.9 ± 1.6 in the SM group and from 2.8 ± 1.9 to 3.6 ± 2.0 in the SI group by ITT analysis, after electrical stimulation (p < 0.001, respectively). However, changes in FDS scores, SFSs, penetration, and aspiration were comparable between the SM and the SI groups. The results suggest that both SM and SI therapies induced similar improvements in swallowing function in brain-injured patients.

Neptune - full ring system

NASA Technical Reports Server (NTRS)

1989-01-01

This pair of Voyager 2 images (FDS 11446.21 and 11448.10), two 591-s exposures obtained through the clear filter of the wide angle camera, show the full ring system with the highest sensitivity. Visible in this figure are the bright, narrow N53 and N63 rings, the diffuse N42 ring, and (faintly) the plateau outside of the N53 ring (with its slight brightening near 57,500 km).

A numerical investigation of the influence of radiation and moisture content on pyrolysis and ignition of a leaf-like fuel element

Treesearch

B.L. Yashwanth; B. Shotorban; S. Mahalingam; C.W. Lautenberger; David Weise

2016-01-01

The effects of thermal radiation and moisture content on the pyrolysis and gas phase ignition of a solid fuel element containing high moisture content were investigated using the coupled Gpyro3D/FDS models. The solid fuel has dimensions of a typical Arctostaphylos glandulosa leaf which is modeled as thin cellulose subjected to radiative heating on...

FdC1 and Leaf-Type Ferredoxins Channel Electrons From Photosystem I to Different Downstream Electron Acceptors.

PubMed

Guan, Xiaoqian; Chen, Shuai; Voon, Chia Pao; Wong, Kam-Bo; Tikkanen, Mikko; Lim, Boon L

2018-01-01

Plant-type ferredoxins in Arabidopsis transfer electrons from the photosystem I to multiple redox-driven enzymes involved in the assimilation of carbon, nitrogen, and sulfur. Leaf-type ferredoxins also modulate the switch between the linear and cyclic electron routes of the photosystems. Recently, two novel ferredoxin homologs with extra C-termini were identified in the Arabidopsis genome (AtFdC1, AT4G14890; AtFdC2, AT1G32550). FdC1 was considered as an alternative electron acceptor of PSI under extreme ferredoxin-deficient conditions. Here, we showed that FdC1 could interact with some, but not all, electron acceptors of leaf-type Fds, including the ferredoxin-thioredoxin reductase (FTR), sulfite reductase (SiR), and nitrite reductase (NiR). Photoreduction assay on cytochrome c and enzyme assays confirmed its capability to receive electrons from PSI and donate electrons to the Fd-dependent SiR and NiR but not to the ferredoxin-NADP + oxidoreductase (FNR). Hence, FdC1 and leaf-type Fds may play differential roles by channeling electrons from photosystem I to different downstream electron acceptors in photosynthetic tissues. In addition, the median redox potential of FdC1 may allow it to receive electrons from FNR in non-photosynthetic plastids.

Particle imaging velocimetry evaluation of intracranial stents in sidewall aneurysm: hemodynamic transition related to the stent design.

PubMed

Bouillot, Pierre; Brina, Olivier; Ouared, Rafik; Lovblad, Karl-Olof; Farhat, Mohamed; Pereira, Vitor Mendes

2014-01-01

We investigated the flow modifications induced by a large panel of commercial-off-the-shelf (COTS) intracranial stents in an idealized sidewall intracranial aneurysm (IA). Flow velocities in IA silicone model were assessed with and without stent implantation using particle imaging velocimetry (PIV). The use of the recently developed multi-time-lag method has allowed for uniform and precise measurements of both high and low velocities at IA neck and dome, respectively. Flow modification analysis of both regular (RSs) and flow diverter stents (FDSs) was subsequently correlated with relevant geometrical stent parameters. Flow reduction was found to be highly sensitive to stent porosity variations for regular stents RSs and moderately sensitive for FDSs. Consequently, two distinct IA flow change trends, with velocity reductions up to 50% and 90%, were identified for high-porosity RS and low-porosity FDS, respectively. The intermediate porosity (88%) regular braided stent provided the limit at which the transition in flow change trend occurred with a flow reduction of 84%. This transition occurred with decreasing stent porosity, as the driving force in IA neck changed from shear stress to differential pressure. Therefore, these results suggest that stents with intermediate porosities could possibly provide similar flow change patterns to FDS, favourable to curative thrombogenesis in IAs.

Effects of mouse slant and desktop position on muscular and postural stresses, subject preference and performance in women aged 18-40 years.

PubMed

Gaudez, Clarisse; Cail, François

2016-11-01

This study compared muscular and postural stresses, performance and subject preference in women aged 18-40 years using a standard mouse, a vertical mouse and a slanted mouse in three different computer workstation positions. Four tasks were analysed: pointing, pointing-clicking, pointing-clicking-dragging and grasping-pointing the mouse after typing. Flexor digitorum superficialis (FDS) and extensor carpi radialis (ECR) activities were greater using the standard mouse compared to the vertical or slanted mouse. In all cases, the wrist position remained in the comfort zone recommended by standard ISO 11228-3. The vertical mouse was less comfortable and more difficult to use than the other two mice. FDS and ECR activities, shoulder abduction and wrist extension were greater when the mouse was placed next to the keyboard. Performance and subject preference were better with the unrestricted mouse positioning on the desktop. Grasping the mouse after typing was the task that caused the greatest stress. Practitioner Summary: In women, the slanted mouse and the unrestricted mouse positioning on the desktop provide a good blend of stresses, performance and preference. Unrestricted mouse positioning requires no keyboard, which is rare in practice. Placing the mouse in front of the keyboard, rather than next to it, reduced the physical load.

FdC1 and Leaf-Type Ferredoxins Channel Electrons From Photosystem I to Different Downstream Electron Acceptors

PubMed Central

Guan, Xiaoqian; Chen, Shuai; Voon, Chia Pao; Wong, Kam-Bo; Tikkanen, Mikko; Lim, Boon L.

2018-01-01

Plant-type ferredoxins in Arabidopsis transfer electrons from the photosystem I to multiple redox-driven enzymes involved in the assimilation of carbon, nitrogen, and sulfur. Leaf-type ferredoxins also modulate the switch between the linear and cyclic electron routes of the photosystems. Recently, two novel ferredoxin homologs with extra C-termini were identified in the Arabidopsis genome (AtFdC1, AT4G14890; AtFdC2, AT1G32550). FdC1 was considered as an alternative electron acceptor of PSI under extreme ferredoxin-deficient conditions. Here, we showed that FdC1 could interact with some, but not all, electron acceptors of leaf-type Fds, including the ferredoxin-thioredoxin reductase (FTR), sulfite reductase (SiR), and nitrite reductase (NiR). Photoreduction assay on cytochrome c and enzyme assays confirmed its capability to receive electrons from PSI and donate electrons to the Fd-dependent SiR and NiR but not to the ferredoxin-NADP+ oxidoreductase (FNR). Hence, FdC1 and leaf-type Fds may play differential roles by channeling electrons from photosystem I to different downstream electron acceptors in photosynthetic tissues. In addition, the median redox potential of FdC1 may allow it to receive electrons from FNR in non-photosynthetic plastids. PMID:29670639

Studies on Batch Production of Bacterial Concentrates from Mixed Species Lactic Starters

PubMed Central

Pettersson, H. E.

1975-01-01

Optimum growth conditions for mixed species starter FDs 0172 at constant pH in skim milk, whey, and tryptone medium were investigated. Growth rate and maximum population were optimal at 30 C. pH values between 5.5 and 7.0 did not influence the growth rate and maximum population obtainable. Lactic acid-producing activity declined rapidly after reaching the end of the exponential growth phase. The bacterial balance was found to be influenced by the growth parameters: media, pH, temperature, and neutralizer. Skim milk or whey medium at 25 C, pH 6.5, and neutralized with 20% (vol/vol) NH4OH kept the bacterial balance almost constant throughout the cultivation. Grown in tryptone medium at constant pH, the changes in bacterial balance and other metabolic activities were striking compared to the other two media tested. The effect of lactate as an inhibitor was found to be complex, changing with the growth conditions. Concentrates made from mixed species starters FDs 0172, FD 0570, CH 0170, CHs 0170, and T 27 were comparable to controls when cultivated at the optimum conditions found and thereafter centrifuged. Aroma production, proteolytic activity, and CO2 production did not change significantly compared to controls when cultivated at optimum conditions in skim milk or whey medium. PMID:16350009

The effect of 630-nm light stimulation on the sEMG signal of forearm muscle

NASA Astrophysics Data System (ADS)

Yang, Dan D.; Hou, W. Sheng; Wu, Xiao Y.; Zheng, Xiao L.; Zheng, Jun; Jiang, Ying T.

2010-11-01

This study aimed to explore if the red light irradiation can affect the electrophysiology performance of flexor digitorum superficialis (FDS) and fatigue recovery. Four healthy volunteers were randomly divided into two groups. In the designed force-tracking tasks, all subjects performed the four fingertip isometric force production except thumb with a load of 30% of the maximum voluntary contraction (MVC) force until exhaustion. Subsequently, for the red light group, red light irradiation (640 nm wavelength, 0.23J/cm2, 20 min) was used on the right forearm; for the control group, the subjects relaxed without red light irradiation. Then subjects were required to perform fatigue trail again, and sEMG signal was collected simultaneously from FDS during finger force production. Average rectified value (ARV) and median frequency (MF) of sEMG were calculated. Compared to the control group, the red light irradiation induced more smoother value of ARV between 30% and 40%, and the value of MF was obviously large and smooth. The above electrophysiological markers indicated that recovery from muscle fatigue may be positively affected by the red light irradiation, suggesting that sEMG would become a power tool for exploring the effect of red light irradiation on local muscle fatigue.

Simulation of a high-efficiency silicon-based heterojunction solar cell

NASA Astrophysics Data System (ADS)

Jian, Liu; Shihua, Huang; Lü, He

2015-04-01

The basic parameters of a-Si:H/c-Si heterojunction solar cells, such as layer thickness, doping concentration, a-Si:H/c-Si interface defect density, and the work functions of the transparent conducting oxide (TCO) and back surface field (BSF) layer, are crucial factors that influence the carrier transport properties and the efficiency of the solar cells. The correlations between the carrier transport properties and these parameters and the performance of a-Si:H/c-Si heterojunction solar cells were investigated using the AFORS-HET program. Through the analysis and optimization of a TCO/n-a-Si:H/i-a-Si:H/p-c-Si/p+-a-Si:H/Ag solar cell, a photoelectric conversion efficiency of 27.07% (VOC) 749 mV, JSC: 42.86 mA/cm2, FF: 84.33%) was obtained through simulation. An in-depth understanding of the transport properties can help to improve the efficiency of a-Si:H/c-Si heterojunction solar cells, and provide useful guidance for actual heterojunction with intrinsic thin layer (HIT) solar cell manufacturing. Project supported by the National Natural Science Foundation of China (No. 61076055), the Open Project Program of Surface Physics Laboratory (National Key Laboratory) of Fudan University (No. FDS-KL2011-04), the Zhejiang Provincial Science and Technology Key Innovation Team (No. 2011R50012), and the Zhejiang Provincial Key Laboratory (No. 2013E10022).

Synergism of the method of characteristics and CAD technology for neutron transport calculation

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

Chen, Z.; Wang, D.; He, T.

2013-07-01

The method of characteristics (MOC) is a very popular methodology in neutron transport calculation and numerical simulation in recent decades for its unique advantages. One of the key problems determining whether the MOC can be applied in complicated and highly heterogeneous geometry is how to combine an effective geometry processing method with MOC. Most of the existing MOC codes describe the geometry by lines and arcs with extensive input data, such as circles, ellipses, regular polygons and combination of them. Thus they have difficulty in geometry modeling, background meshing and ray tracing for complicated geometry domains. In this study, amore » new idea making use of a CAD solid modeler MCAM which is a CAD/Image-based Automatic Modeling Program for Neutronics and Radiation Transport developed by FDS Team in China was introduced for geometry modeling and ray tracing of particle transport to remove these geometrical limitations mentioned above. The diamond-difference scheme was applied to MOC to reduce the spatial discretization error of the flat flux approximation in theory. Based on MCAM and MOC, a new MOC code was developed and integrated into SuperMC system, which is a Super Multi-function Computational system for neutronics and radiation simulation. The numerical testing results demonstrated the feasibility and effectiveness of the new idea for geometry treatment in SuperMC. (authors)« less

Application of CFD Modeling to Room Fire Growth on Walls

DTIC Science & Technology

2003-04-01

to each particle. For fires of other geometries, expressions must be available for representing the characteristic velocity and flame length , in the...burning time, z , is the flame length , ri,, is the selected particle rate. The velocity of the particles generally depends on their launch site. But if...over the characteristic flame length , We used R* = 0.05 or 20 cells over the characteristic flame length . In FDS 2.0 the stoichiometric mixture

Environmental Control and Life Support System

NASA Technical Reports Server (NTRS)

Ray, Charles; Adams, Alan

1990-01-01

Viewgraphs on the Environmental Control and Life Support System (ECLSS) for the space station are presented. The ECLSS is divided into six subsystems: temperature and humidity control (THC), atmosphere control and supply (ACS), atmosphere revitalization (AR), fire detection and suppression (FDS), water recovery management (WRM), and waste management (WM). Topics covered include: ECLSS subsystem functions; ECLSS distributed system; ECLSS functional distribution; CO2 removal; CO2 reduction; oxygen generation; urine processor; and potable water recovery.

Clinical outcomes of individualized botulinum neurotoxin type A injection techniques in patients with essential blepharospasm.

PubMed

Sung, Youngje; Nam, Sang Min; Lew, Helen

2015-04-01

To assess the clinical outcomes following botulinum neurotoxin type A (BoNT-A) treatment with an individualized injection technique based on the types of spasms and to compare the results of the individualized injection technique with those of the conventional injection technique in the same patients. From November 2011 to July 2013, 77 BoNT-A injections were performed in 38 patients. Eighteen patients were treated with conventional BoNT-A injections before 2011, and 20 patients were referred to our hospital for unsatisfactory results after a conventional injection technique. We classified the patients by spasm-dominant sites: the lateral orbital area, representing the orbital orbicularis-dominant group (ODG); the glabella, representing the corrugator-dominant group (CDG); and the ptosis, representing the palpebral part of the orbicularis-dominant group (PDG). We increased the injection dose into the spasm-dominant sites of the blepharospasm groups. We assessed subjective symptom scores (functional disability score, FDS) after treatment. This study included 38 patients (26 women, 12 men; mean age, 60.6 ± 10.9 years). There were 21 patients in the ODG, 10 patients in the CDG, and 7 patients in the PDG. Mean ages were 59.7 ± 12.6, 59.8 ± 8.5, and 66.8 ± 9.0 years, and mean BoNT-A injection dose was 38.8 ± 11.2, 38.8 ± 11.2, and 38.8 ± 10.8 U in each group, respectively (p = 0.44, 0.82 Kruskal-Wallis test). Mean FDS after injection was 1.7 ± 0.7 in the ODG, 1.4 ± 0.8 in the CDG, and 1.2 ± 0.3 in the PDG. There were significant differences in reading and job scale among the three groups. In a comparison between the conventional and individualized injection techniques, there was a significant improvement in mean FDS and in the reading scale in the PDG with the individualized injection technique. The success rate was 92.1% in the conventional injection group and 94.1% in the individualized injection group. The individualized injection technique of BoNT-A according to the spasm-dominant site is an effective and safe treatment method for essential blepharospasm patients.

Electron transfer to nitrogenase in different genomic and metabolic backgrounds.

PubMed

Poudel, Saroj; Colman, Daniel R; Fixen, Kathryn R; Ledbetter, Rhesa N; Zheng, Yanning; Pence, Natasha; Seefeldt, Lance C; Peters, John W; Harwood, Caroline S; Boyd, Eric S

2018-02-26

Nitrogenase catalyzes the reduction of dinitrogen (N 2 ) using low potential electrons from ferredoxin (Fd) or flavodoxin (Fld) through an ATP dependent process. Since its emergence in an anaerobic chemoautotroph, this oxygen (O 2 ) sensitive enzyme complex has evolved to operate in a variety of genomic and metabolic backgrounds including those of aerobes, anaerobes, chemotrophs, and phototrophs. However, whether pathways of electron delivery to nitrogenase are influenced by these different metabolic backgrounds is not well understood. Here, we report the distribution of homologs of Fds, Flds, and Fd/Fld-reducing enzymes in 359 genomes of putative N 2 fixers (diazotrophs). Six distinct lineages of nitrogenase were identified and their distributions largely corresponded to differences in the host cells' ability to integrate O 2 or light into energy metabolism. Predicted pathways of electron transfer to nitrogenase in aerobes, facultative anaerobes, and phototrophs varied from those in anaerobes at the level of Fds/Flds used to reduce nitrogenase, the enzymes that generate reduced Fds/Flds, and the putative substrates of these enzymes. Proteins that putatively reduce Fd with hydrogen or pyruvate were enriched in anaerobes, while those that reduce Fd with NADH/NADPH were enriched in aerobes, facultative anaerobes, and anoxygenic phototrophs. The energy metabolism of aerobic, facultatively anaerobic, and anoxygenic phototrophic diazotrophs often yields reduced NADH/NADPH that is not sufficiently reduced to drive N 2 reduction. At least two mechanisms have been acquired by these taxa to overcome this limitation and to generate electrons with potentials capable of reducing Fd. These include the bifurcation of electrons or the coupling of Fd reduction to reverse ion translocation. IMPORTANCE Nitrogen fixation supplies fixed nitrogen to cells from a variety of genomic and metabolic backgrounds including those of aerobes, facultative anaerobes, chemotrophs, and phototrophs. Here, using informatics approaches applied to genomic data, we show that pathways of electron transfer to nitrogenase in metabolically diverse diazotrophic taxa have diversified primarily in response to host cells' acquired ability to integrate O 2 or light into their energy metabolism. Acquisition of two key enzyme complexes enabled aerobic and facultatively anaerobic phototrophic taxa to generate electrons of sufficiently low potential to reduce nitrogenase: the bifurcation of electrons via the Fix complex or the coupling of Fd reduction to reverse ion translocation via the Rhodobacter nitrogen fixation (Rnf) complex. Copyright © 2018 American Society for Microbiology.

Recurrent Renal Colic in a Patient with Munchausen Syndrome

PubMed Central

Miconi, Francesco; Rapaccini, Valentina; Savarese, Emanuela; Cabiati, Gabriele; Pasini, Augusto; Miconi, Giovanni; Principi, Nicola

2018-01-01

Background: In most of the cases regarding children, factitious disorders (FDs) are intentionally produced by parents. Less attention is paid to FDs in which a child or adolescent intentionally induces or falsifies the disease to attain a patient’s role. Case presentation: A 13-year-old immigrated and adopted boy previously underwent an operation for renal joint syndrome and was affected by recurrent episodes of renal colic. The boy was admitted reporting acute left flank pain with scars on the mucous face of his prepuce and had a recent previous hospitalization for the same reason. Laboratory tests and radiological findings did not reveal any morphological or functional alterations. Self-induced FD was suspected, and a psychiatric consultation was performed. After psychiatric consultation and remission of the symptoms with a placebo, a diagnosis of Munchausen syndrome was suspected. The patient’s uncle was not initially convinced of the diagnosis. Some videos clearly showed that the boy was handling his prepuce to excrete stones, explaining the scars. A therapeutic plan with psychiatrist support was later accepted with a positive outcome. No further signs and symptoms of renal colic were reported. Conclusions: It is recommended that paediatricians include FD in the differential diagnosis of a persistent and unexplained medical condition. If suspicion arises, confirmation and long-term therapy by a group of qualified specialists, including psychiatrists, should be planned. PMID:29596350

A snapshot of the organization and provision of primary care in Turkey

PubMed Central

2011-01-01

Background This WHO study aimed to support Turkey in its efforts to strengthen the primary care (PC) system by implementing the WHO Primary Care Evaluation Tool (PCET). This article provides an overview of the organization and provision of primary care in Turkey. Methods The WHO Primary Care Evaluation Tool was implemented in two provinces (Bolu and Eskişehir) in Turkey in 2007/08. The Tool consists of three parts: a national questionnaire concerning the organisation and financing of primary care; a questionnaire for family doctors; and a questionnaire for patients who visit a family health centre. Results Primary care has just recently become an official health policy priority with the introduction of a family medicine scheme. Although the supply of family doctors (FDs) has improved, they are geographically uneven distributed, and nationwide shortages of primary care staff remain. Coordination of care could be improved and quality control mechanisms were lacking. However, patients were very satisfied with the treatment by FDs. Conclusions The study provides an overview of the current state of PC in Turkey for two provinces with newly introduced family medicine, by using a structured approach to evaluate the essential functions of PC, including governance, financing, resource generation, as well as the characteristics of a "good" service delivery system (as being accessible, comprehensive, coordinated and continuous). PMID:21542904

Directing an artificial zinc finger protein to new targets by fusion to a non-DNA-binding domain.

PubMed

Lim, Wooi F; Burdach, Jon; Funnell, Alister P W; Pearson, Richard C M; Quinlan, Kate G R; Crossley, Merlin

2016-04-20

Transcription factors are often regarded as having two separable components: a DNA-binding domain (DBD) and a functional domain (FD), with the DBD thought to determine target gene recognition. While this holds true for DNA bindingin vitro, it appears thatin vivoFDs can also influence genomic targeting. We fused the FD from the well-characterized transcription factor Krüppel-like Factor 3 (KLF3) to an artificial zinc finger (AZF) protein originally designed to target the Vascular Endothelial Growth Factor-A (VEGF-A) gene promoter. We compared genome-wide occupancy of the KLF3FD-AZF fusion to that observed with AZF. AZF bound to theVEGF-Apromoter as predicted, but was also found to occupy approximately 25,000 other sites, a large number of which contained the expected AZF recognition sequence, GCTGGGGGC. Interestingly, addition of the KLF3 FD re-distributes the fusion protein to new sites, with total DNA occupancy detected at around 50,000 sites. A portion of these sites correspond to known KLF3-bound regions, while others contained sequences similar but not identical to the expected AZF recognition sequence. These results show that FDs can influence and may be useful in directing AZF DNA-binding proteins to specific targets and provide insights into how natural transcription factors operate. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

Functional Characterization of Novel Sesquiterpene Synthases from Indian Sandalwood, Santalum album

PubMed Central

Srivastava, Prabhakar Lal; Daramwar, Pankaj P.; Krithika, Ramakrishnan; Pandreka, Avinash; Shankar, S. Shiva; Thulasiram, Hirekodathakallu V.

2015-01-01

Indian Sandalwood, Santalum album L. is highly valued for its fragrant heartwood oil and is dominated by a blend of sesquiterpenes. Sesquiterpenes are formed through cyclization of farnesyl diphosphate (FPP), catalyzed by metal dependent terpene cyclases. This report describes the cloning and functional characterization of five genes, which encode two sesquisabinene synthases (SaSQS1, SaSQS2), bisabolene synthase (SaBS), santalene synthase (SaSS) and farnesyl diphosphate synthase (SaFDS) using the transcriptome sequencing of S. album. Using Illumina next generation sequencing, 33.32 million high quality raw reads were generated, which were assembled into 84,094 unigenes with an average length of 494.17 bp. Based on the transcriptome sequencing, five sesquiterpene synthases SaFDS, SaSQS1, SaSQS2, SaBS and SaSS involved in the biosynthesis of FPP, sesquisabinene, β-bisabolene and santalenes, respectively, were cloned and functionally characterized. Novel sesquiterpene synthases (SaSQS1 and SaSQS2) were characterized as isoforms of sesquisabinene synthase with varying kinetic parameters and expression levels. Furthermore, the feasibility of microbial production of sesquisabinene from both the unigenes, SaSQS1 and SaSQS2 in non-optimized bacterial cell for the preparative scale production of sesquisabinene has been demonstrated. These results may pave the way for in vivo production of sandalwood sesquiterpenes in genetically tractable heterologous systems. PMID:25976282

Functional Characterization of Novel Sesquiterpene Synthases from Indian Sandalwood, Santalum album.

PubMed

Srivastava, Prabhakar Lal; Daramwar, Pankaj P; Krithika, Ramakrishnan; Pandreka, Avinash; Shankar, S Shiva; Thulasiram, Hirekodathakallu V

2015-05-15

Indian Sandalwood, Santalum album L. is highly valued for its fragrant heartwood oil and is dominated by a blend of sesquiterpenes. Sesquiterpenes are formed through cyclization of farnesyl diphosphate (FPP), catalyzed by metal dependent terpene cyclases. This report describes the cloning and functional characterization of five genes, which encode two sesquisabinene synthases (SaSQS1, SaSQS2), bisabolene synthase (SaBS), santalene synthase (SaSS) and farnesyl diphosphate synthase (SaFDS) using the transcriptome sequencing of S. album. Using Illumina next generation sequencing, 33.32 million high quality raw reads were generated, which were assembled into 84,094 unigenes with an average length of 494.17 bp. Based on the transcriptome sequencing, five sesquiterpene synthases SaFDS, SaSQS1, SaSQS2, SaBS and SaSS involved in the biosynthesis of FPP, sesquisabinene, β-bisabolene and santalenes, respectively, were cloned and functionally characterized. Novel sesquiterpene synthases (SaSQS1 and SaSQS2) were characterized as isoforms of sesquisabinene synthase with varying kinetic parameters and expression levels. Furthermore, the feasibility of microbial production of sesquisabinene from both the unigenes, SaSQS1 and SaSQS2 in non-optimized bacterial cell for the preparative scale production of sesquisabinene has been demonstrated. These results may pave the way for in vivo production of sandalwood sesquiterpenes in genetically tractable heterologous systems.

Flow Diverter Stents for the Treatment of Anterior Cerebral Artery Aneurysms: Safety and Effectiveness.

PubMed

Clarençon, F; Di Maria, F; Gabrieli, J; Shotar, E; Zeghal, C; Nouet, A; Chiras, J; Sourour, N-A

2017-03-01

Flow diverter stents (FDSs) are increasingly used for the treatment of intracranial aneurysms. Initially developed for the management of giant and large aneurysms, their indications have progressively expanded. The purpose of our study was to evaluate the safety and effectiveness of FDSs for the treatment of anterior cerebral artery (ACA) aneurysms. Among the 94 consecutive patients treated for 100 intracranial aneurysms by means of FDSs in our institution from October 2010 to January 2015, eight aneurysms (8 %) in seven patients were located on the ACA. Three aneurysms were located on the A1 segment, three aneurysms on the anterior communicating artery (ACom) and two on the A2-A3 junction. In three cases, FDS was used for angiographic recurrence after coiling. Five patients were treated with a Pipeline embolization device, one with a NeuroEndograft and the last one with a Silk FDS. Treatment was feasible in all cases. No technical difficulty was reported. No acute or delayed clinical complication was recorded. Modified Rankin Scale was 0 for six patients and one for one patient. Mean angiographic follow-up was 9.7 ± 3.9 months (range 6-15). Total exclusion was observed in five aneurysms (71.4 %) and neck remnant in two (28.6 %) cases. One patient refused the control DSA. Our series shows the safety and effectiveness of FDSs for the treatment of ACA aneurysms.

Correlation between Hemodynamics and Treatment Outcome of Intracranial Aneurysms after Intervention with Flow Diverters

NASA Astrophysics Data System (ADS)

Paliwal, Nikhil; Damiano, Robert; Davies, Jason; Siddiqui, Adnan; Meng, Hui

2015-11-01

Endovascular intervention by Flow Diverter (FD) - a densely woven stent - occludes an aneurysm by inducing thrombosis in the aneurysm sac and reconstructing the vessel. Hemodynamics plays a vital role in the thrombotic occlusion of aneurysms and eventual treatment outcome. CFD analysis of pre- and post-treatment aneurysms not only provides insight of flow modifications by FD, but also allows investigation of interventional strategies and prediction of their outcome. In this study 80 patient-specific aneurysms treated with FDs were retrospectively studied to evaluate the effect of intervention. Out of these cases, 16 required retreatment and thus are considered as having unfavorable outcome. Clinical FD deployment in these cases was simulated using an efficient virtual stenting workflow. CFD analysis was carried out on both pre- and post-treatment cases, and changes in hemodynamic parameters were calculated. Support vector machine algorithm was used to correlate the hemodynamic changes with outcome. Results show that cases having higher flow reduction into the aneurysmal sac have a better likelihood of occlusion. This suggests that changes in hemodynamics can be potentially used to predict the outcome of different clinical intervention strategies in aneurysms. This work was supported by the National Institutes of Health (R01 NS091075).

The Influence of Climate Change on CO2 and CH4 Concentration Near Closed Shaft - Numerical Simulations

NASA Astrophysics Data System (ADS)

Wrona, Paweł

2017-09-01

Given the scientific consensus pointing to climate change, the more extreme weather events associated with this will lead to deeper pressure drops. As has already been stated, pressure drops are the main cause of gas flow from underground sites to the surface. This article presents the results of numerical simulations of the change in distribution of CO2 and CH4 near a closed mining shaft under the predicted baric tendency. Simulations have been undertaken by means of the FDS software package with the Pyrosim graphical interface - a CFD tool for fire and ventilation analysis. Assumptions have been based on previous results of in-situ measurements. The results (determined for a height of 1m above the ground) were compared to the following levels (later in the text comparison levels): for CO2 0.1%vol. according to Pettenkoffer's scale and 2.5%vol. for CH4 as the half of Lower Explosive Limit (LEL). The results show that the deeper baric drops anticipated could lead to a wider spread of both greenhouse gases in the vicinity of the shaft, especially along the prevailing wind direction. According to the results obtained, CO2 and CH4 with concentrations above their comparison levels are expected at a distance greater than 50m from the shaft when wind is present for CO2 and at a distance of 4.5m for CH4. Subsequent analysis of the results enabled the determination of functions for describing the concentration of gases along the wind direction line under the projected pressure drop. The results relate to a particular case, although the model could easily be modified to any other example of gas emissions from underground sites.

International Space Station Atmosphere Control and Supply, Atmosphere Revitalization, and Water Recovery and Management Subsystem - Verification for Node 1

NASA Technical Reports Server (NTRS)

Williams, David E.

2007-01-01

The International Space Station (ISS) Node 1 Environmental Control and Life Support (ECLS) System is comprised of five subsystems: Atmosphere Control and Supply (ACS), Atmosphere Revitalization (AR), Fire Detection and Suppression (FDS), Temperature and Humidity Control (THC), and Water Recovery and Management (WRM). This paper provides a summary of the nominal operation of the Node 1 ACS, AR, and WRM design and detailed Element Verification methodologies utilized during the Qualification phase for Node 1.

International Space Station Environmental Control and Life Support System Acceptance Testing for Node 1 Atmosphere Control and Supply Subsystem

NASA Technical Reports Server (NTRS)

Williams, David E.

2009-01-01

The International Space Station (ISS) Node 1 Environmental Control and Life Support (ECLS) System is comprised of five subsystems: Atmosphere Control and Supply (ACS), Atmosphere Revitalization (AR), Fire Detection and Suppression (FDS), Temperature and Humidity Control (THC), and Water Recovery and Management (WRM). This paper provides a summary of the Node 1 ECLS ACS subsystem design and a detailed discussion of the ISS ECLS Acceptance Testing methodology utilized for that subsystem.

Charmed-meson decay constants in three-flavor lattice QCD.

PubMed

Aubin, C; Bernard, C; Detar, C; Di Pierro, M; Freeland, E D; Gottlieb, Steven; Heller, U M; Hetrick, J E; El-Khadra, A X; Kronfeld, A S; Levkova, L; Mackenzie, P B; Menscher, D; Maresca, F; Nobes, M; Okamoto, M; Renner, D; Simone, J; Sugar, R; Toussaint, D; Trottier, H D

2005-09-16

We present the first lattice QCD calculation with realistic sea quark content of the D+-meson decay constant f(D+). We use the MILC Collaboration's publicly available ensembles of lattice gauge fields, which have a quark sea with two flavors (up and down) much lighter than a third (strange). We obtain f(D+)=201+/-3+/-17 MeV, where the errors are statistical and a combination of systematic errors. We also obtain f(Ds)=249+/-3+/-16 MeV for the Ds meson.

Regional cerebral blood flow correlates of the severity of writer's cramp symptoms.

PubMed

Lerner, Alicja; Shill, Holly; Hanakawa, Takashi; Bushara, Khalaf; Goldfine, Andrew; Hallett, Mark

2004-03-01

Writer's cramp is a type of idiopathic focal dystonia with incompletely understood pathophysiology. Recent studies provide evidence that one element might be a sensory processing defect. We performed a PET study with O(15) H(2)O to find out in which brain areas activity correlates with the severity of writer's cramp symptoms. We studied 10 patients with writer's cramp and 10 age- and gender-matched control subjects. There were seven conditions, each repeated twice: rest, writing, tapping with index finger for 2, 3, 4, and 5 min. For each scan, we obtained EMG recordings from the flexor digitorum superficialis (FDS), extensor indicis proprius (EIP) muscles, and a subjective score of severity of dystonia. Scans were realigned, normalized, smoothed, and analyzed using SPM99. Analysis included both intra- and intergroup comparisons and a correlation analysis where we used EMG recordings and subjective dystonia score as covariates. Random effect analysis of the writing task showed overactivity of the primary sensory cortex and no significant underactivity. Correlation analysis of dystonia patients showed activation of SI when we used the subjective dystonia score as a covariate, and activation of both the SI and primary motor cortex when the normalized EMG score of FDS was used. While some overactivity of MI is not surprising, overactivity of SI is more dramatic and suggests a primary deficit in processing sensory feedback. Writer's cramp may arise in part as a dysfunction of sensory circuits, which causes defective sensorimotor integration resulting in co-contractions of muscles and overflow phenomena.

Comparison of dysphagia outcomes between rostral and caudal lateral medullary infarct patients.

PubMed

Chun, Min Ho; Kim, Daeha; Chang, Min Cheol

2017-11-01

A detailed knowledge of dysphagia outcomes in lateral medullary infarct (LMI) patients would enable proper establishment of swallowing therapy goals and strategies. However, little is known about the impact of infarct location on dysphagia outcomes in patients with LMI. Twenty patients with rostral LMI (rostral group) and 20 patients with caudal LMI (caudal group) participated in the study. All patients underwent swallowing therapy, which included compensatory treatments and strengthening exercises, for >3 months. Dysphagia evaluation was performed twice (during the subacute stage and six months after stroke onset) using videofluoroscopic swallowing studies. Dysphagia degree was assessed using the functional dysphagia scale (FDS), the penetration-aspiration scale (PAS) and the American Speech-Language-Hearing Association (ASHA) National Outcome Measurement System (NOMS) swallowing scale. In the subacute stage, the rostral group had significantly higher FDS and PAS scores and a significantly lower ASHA NOMS score than the caudal group. Patients from both groups showed significant improvement from the initial evaluation to the six-month evaluation. There were no significant differences in these scale scores between the two groups at the six-month evaluation. In the subacute stage, patients in the rostral group had more severe dysphagia than those in the caudal group. Dysphagia improved in both groups after 3-6 months of swallowing therapy. At six months after onset, there were no significant differences in dysphagia severity between the two groups. Recovery from dysphagia after LMI was observed regardless of the infarct location.

A dual-wavelength overlapping resonance Rayleigh scattering method for the determination of chondroitin sulfate with nile blue sulfate

NASA Astrophysics Data System (ADS)

Cui, Zhiping; Hu, Xiaoli; Liu, Shaopu; Liu, Zhongfang

2011-12-01

A dual-wavelength overlapping resonance Rayleigh scattering (DWO-RRS) method was developed to detect chondroitin sulfate (CS) with nile blue sulfate (NBS). At pH 3.0-4.0 Britton-Robinson (BR) buffer medium, CS interacted with NBS to form an ion-association complex. As a result, the new spectra of resonance Rayleigh scattering (RRS), second order scattering (SOS) and frequence doubling scattering (FDS) appeared and their intensities were enhanced greatly. Their maximum wavelengths were located at 303 nm (RRS), 362 nm (RRS), 588 nm (SOS) and 350 nm (FDS), respectively. The scattering intensities of the three methods were proportional to the concentration of CS in certain ranges. The methods had high sensitivity and the detection limits were between 1.5 and 7.1 ng mL -1. The DWO-RRS method had the highest sensitivity with the detection limit being 1.5 ng mL -1. The characteristics of the spectra and optimal reaction conditions of RRS method were investigated. The effects of coexistent substances on the determination of CS were evaluated. Owing to the high sensitivity, RRS method had been applied to the determination of CS in eye drops with satisfactory results. The recovery range was between 99.4% and 104.6% and the relative standard deviation (RSD) was between 0.4% and 0.8%. In addition, the reasons for RRS enhancement were discussed and the shape of ion-association complex was characterized by atomic force microscopy (AFM).

Surgical flow disruptions during robotic-assisted radical prostatectomy.

PubMed

Dru, Christopher J; Anger, Jennifer T; Souders, Colby P; Bresee, Catherine; Weigl, Matthias; Hallett, Elyse; Catchpole, Ken

2017-06-01

We sought to apply the principles of human factors research to robotic-assisted radical prostatectomy to understand where training and integration challenges lead to suboptimal and inefficient care. Thirty-four robotic-assisted radical prostatectomy and bilateral pelvic lymph node dissections over a 20 week period were observed for flow disruptions (FD) - deviations from optimal care that can compromise safety or efficiency. Other variables - physician experience, trainee involvement, robot model (S versus Si), age, body mass index (BMI), and American Society of Anesthesiologists (ASA) physical status - were used to stratify the data and understand the effect of context. Effects were studied across four operative phases - entry to insufflations, robot docking, surgical intervention, and undocking. FDs were classified into one of nine categories. An average of 9.2 (SD = 3.7) FD/hr were recorded, with the highest rates during robot docking (14.7 [SD = 4.3] FDs/hr). The three most common flow disruptions were disruptions of communication, coordination, and equipment. Physicians with more robotic experience were faster during docking (p < 0.003). Training cases had a greater FD rate (8.5 versus 10.6, p < 0.001), as did the Si model robot (8.2 versus 9.8, p = 0.002). Patient BMI and ASA classification yielded no difference in operative duration, but had phase-specific differences in FD. Our data reflects the demands placed on the OR team by the patient, equipment, environment and context of a robotic surgical intervention, and suggests opportunities to enhance safety, quality, efficiency, and learning in robotic surgery.

Smoke Detection for the Orion Crew Exploration Vehicle

NASA Technical Reports Server (NTRS)

Sutin, Brian M.; Niu, William; Steiner, George; O'Hara, William; Lewis, John F.

2009-01-01

The Orion Crew Exploration Vehicle (CEV) requires a smoke detector for the detection of particulate smoke products as part of the Fire Detection and Suppression (FDS) system. The smoke detector described in this paper is an adaptation of a mature commercial aircraft design for manned spaceflight. Changes made to the original design include upgrading the materials and electronic to space-qualified parts, and modifying the mechanical design to withstand launch and landing loads. The results of laboratory characterization of the response of the new design to test particles are presented.

International Space Station Temperature and Humidity Control Subsystem Verification for Node 1

NASA Technical Reports Server (NTRS)

Williams, David E.

2007-01-01

The International Space Station (ISS) Node 1 Environmental Control and Life Support (ECLS) System is comprised of five subsystems: Atmosphere Control and Supply (ACS), Atmosphere Revitalization (AR), Fire Detection and Suppression (FDS), Temperature and Humidity Control (THC), and Water Recovery and Management (WRM). This paper provides a summary of the nominal operation of the Node 1 THC subsystem design. The paper will also provide a discussion of the detailed Element Verification methodologies for nominal operation of the Node 1 THC subsystem operations utilized during the Qualification phase.

The decision to extract or retain compromised teeth is not helped by the application of a scoring system.

PubMed

Palmer, Richard M

2010-06-01

A Novel Decision-Making Process for Tooth Retention or Extraction J Periodontol 2009;80:476-491. Avila G, Galindo-Moreno P, Soehren S, Misch CE, Morelli T, Wang H-L. Richard M. Palmer, PhD, BDS, FDS RCS PURPOSE/QUESTION: Is it possible to devise a system to help in the decision-making process of tooth extraction/retention based on a critical evaluation of the literature? University of Michigan Periodontal Graduate Student Research Fund Comprehensive literature review Level 3: Other evidence Not applicable.

Field by field hybrid upwind splitting methods

NASA Technical Reports Server (NTRS)

Coquel, Frederic; Liou, Meng-Sing

1993-01-01

A new and general approach to upwind splitting is presented. The design principle combines the robustness of flux vector splitting schemes in the capture of nonlinear waves and the accuracy of some flux difference splitting schemes in the resolution of linear waves. The new schemes are derived following a general hybridization technique performed directly at the basic level of the field by field decomposition involved in FDS methods. The scheme does not use a spatial switch to be tuned up according to the local smoothness of the approximate solution.

Anomalous vibrational modes in acetanilide: a F.D.S. incoherent inelastic neutron scattering study

NASA Astrophysics Data System (ADS)

Barthes, Mariette; Eckert, Juergen; Johnson, Susanna W.; Moret, Jacques; Swanson, Basil I.; Unkefer, Clifford J.

The origin of the anomalous infra-red and Raman modes in acetanilide (C6H5NHCOCH3, or ACN)(1) , remains a subject of considerable controversy. One family of theoretical models involves Davydov-like solitons (2) nonlinear vibrational coupling (3), or "polaronic" localized modes (4)(5). An alternative interpretation of the extra-bands in terms of a Fermi resonance was proposed (6) and recently the existence of slightly non-degenerate hydrogen atom configurations (7) in the H-bond was suggested as an explanation for the anomalies.

Effect of varying two key parameters in simulating evacuation for a dormitory in China

NASA Astrophysics Data System (ADS)

Lei, Wenjun; Li, Angui; Gao, Ran

2013-01-01

Student dormitories are both living and resting areas for students in their spare time. There are many small rooms in the dormitories. And the students are distributed densely in the dormitories. High occupant density is the main characteristic of student dormitories. Once there is an accident, such as fire or earthquake, the losses will be cruel. Computer evacuation models developed overseas are commonly applied in working out safety management schemes. The average minimum widths of corridor and exit are the two key parameters affecting the evacuation for the dormitory. The effect of varying these two parameters will be studied in this paper by taking a dormitory in our university as an example. Evacuation performance is predicted with the software FDS + Evac. The default values in the software are used and adjusted through a field survey. The effect of varying either of the two parameters is discussed. It is found that the simulated results agree well with the experimental results. From our study it seems that the evacuation time is not in proportion to the evacuation distance. And we also named a phenomenon of “the closer is not the faster”. For the building researched in this article, a corridor width of 3 m is the most appropriate. And the suitable exit width of the dormitory for evacuation is about 2.5 to 3 m. The number of people has great influence on the walking speed of people. The purpose of this study is to optimize the building, and to make the building in favor of personnel evacuation. Then the damage could be minimized.

COLLABORATIVE RESEARCH AND DEVELOPMENT (CR&D) Delivery Order 0059: Molecular Dynamics Modeling Support

DTIC Science & Technology

2008-03-01

Molecular Dynamics Simulations 5 Theory: Equilibrium Molecular Dynamics Simulations 6 Theory: Non...Equilibrium Molecular Dynamics Simulations 8 Carbon Nanotube Simulations : Approach and results from equilibrium and non-equilibrium molecular dynamics ...touched from the perspective of molecular dynamics simulations . However, ordered systems such as “Carbon Nanotubes” have been investigated in terms

Thermal neutron flux measurement using self-powered neutron detector (SPND) at out-core locations of TRIGA PUSPATI Reactor (RTP)

NASA Astrophysics Data System (ADS)

Ali, Nur Syazwani Mohd; Hamzah, Khaidzir; Mohamad Idris, Faridah; Hairie Rabir, Mohamad

2018-01-01

The thermal neutron flux measurement has been conducted at the out-core location using self-powered neutron detectors (SPNDs). This work represents the first attempt to study SPNDs as neutron flux sensor for developing the fault detection system (FDS) focusing on neutron flux parameters. The study was conducted to test the reliability of the SPND’s signal by measuring the neutron flux through the interaction between neutrons and emitter materials of the SPNDs. Three SPNDs were used to measure the flux at four different radial locations which located at the fission chamber cylinder, 10cm above graphite reflector, between graphite reflector and tank liner and fuel rack. The measurements were conducted at 750 kW reactor power. The outputs from SPNDs were collected through data acquisition system and were corrected to obtain the actual neutron flux due to delayed responses from SPNDs. The measurements showed that thermal neutron flux between fission chamber location near to the tank liner and fuel rack were between 5.18 × 1011 nv to 8.45 × 109 nv. The average thermal neutron flux showed a good agreement with those from previous studies that has been made using simulation at the same core configuration at the nearest irradiation facilities with detector locations.

High frequency dynamic engine simulation. [TF-30 engine

NASA Technical Reports Server (NTRS)

Schuerman, J. A.; Fischer, K. E.; Mclaughlin, P. W.

1977-01-01

A digital computer simulation of a mixed flow, twin spool turbofan engine was assembled to evaluate and improve the dynamic characteristics of the engine simulation to disturbance frequencies of at least 100 Hz. One dimensional forms of the dynamic mass, momentum and energy equations were used to model the engine. A TF30 engine was simulated so that dynamic characteristics could be evaluated against results obtained from testing of the TF30 engine at the NASA Lewis Research Center. Dynamic characteristics of the engine simulation were improved by modifying the compression system model. Modifications to the compression system model were established by investigating the influence of size and number of finite dynamic elements. Based on the results of this program, high frequency engine simulations using finite dynamic elements can be assembled so that the engine dynamic configuration is optimum with respect to dynamic characteristics and computer execution time. Resizing of the compression systems finite elements improved the dynamic characteristics of the engine simulation but showed that additional refinements are required to obtain close agreement simulation and actual engine dynamic characteristics.

Reconstruction of Human Monte Carlo Geometry from Segmented Images

NASA Astrophysics Data System (ADS)

Zhao, Kai; Cheng, Mengyun; Fan, Yanchang; Wang, Wen; Long, Pengcheng; Wu, Yican

2014-06-01

Human computational phantoms have been used extensively for scientific experimental analysis and experimental simulation. This article presented a method for human geometry reconstruction from a series of segmented images of a Chinese visible human dataset. The phantom geometry could actually describe detailed structure of an organ and could be converted into the input file of the Monte Carlo codes for dose calculation. A whole-body computational phantom of Chinese adult female has been established by FDS Team which is named Rad-HUMAN with about 28.8 billion voxel number. For being processed conveniently, different organs on images were segmented with different RGB colors and the voxels were assigned with positions of the dataset. For refinement, the positions were first sampled. Secondly, the large sums of voxels inside the organ were three-dimensional adjacent, however, there were not thoroughly mergence methods to reduce the cell amounts for the description of the organ. In this study, the voxels on the organ surface were taken into consideration of the mergence which could produce fewer cells for the organs. At the same time, an indexed based sorting algorithm was put forward for enhancing the mergence speed. Finally, the Rad-HUMAN which included a total of 46 organs and tissues was described by the cuboids into the Monte Carlo Monte Carlo Geometry for the simulation. The Monte Carlo geometry was constructed directly from the segmented images and the voxels was merged exhaustively. Each organ geometry model was constructed without ambiguity and self-crossing, its geometry information could represent the accuracy appearance and precise interior structure of the organs. The constructed geometry largely retaining the original shape of organs could easily be described into different Monte Carlo codes input file such as MCNP. Its universal property was testified and high-performance was experimentally verified

A data-driven dynamics simulation framework for railway vehicles

NASA Astrophysics Data System (ADS)

Nie, Yinyu; Tang, Zhao; Liu, Fengjia; Chang, Jian; Zhang, Jianjun

2018-03-01

The finite element (FE) method is essential for simulating vehicle dynamics with fine details, especially for train crash simulations. However, factors such as the complexity of meshes and the distortion involved in a large deformation would undermine its calculation efficiency. An alternative method, the multi-body (MB) dynamics simulation provides satisfying time efficiency but limited accuracy when highly nonlinear dynamic process is involved. To maintain the advantages of both methods, this paper proposes a data-driven simulation framework for dynamics simulation of railway vehicles. This framework uses machine learning techniques to extract nonlinear features from training data generated by FE simulations so that specific mesh structures can be formulated by a surrogate element (or surrogate elements) to replace the original mechanical elements, and the dynamics simulation can be implemented by co-simulation with the surrogate element(s) embedded into a MB model. This framework consists of a series of techniques including data collection, feature extraction, training data sampling, surrogate element building, and model evaluation and selection. To verify the feasibility of this framework, we present two case studies, a vertical dynamics simulation and a longitudinal dynamics simulation, based on co-simulation with MATLAB/Simulink and Simpack, and a further comparison with a popular data-driven model (the Kriging model) is provided. The simulation result shows that using the legendre polynomial regression model in building surrogate elements can largely cut down the simulation time without sacrifice in accuracy.

Protein Folding Simulations Combining Self-Guided Langevin Dynamics and Temperature-Based Replica Exchange

DTIC Science & Technology

2010-01-01

formulations of molecular dynamics (MD) and Langevin dynamics (LD) simulations for the prediction of thermodynamic folding observables of the Trp-cage...ad hoc force term in the SGLD model. Introduction Molecular dynamics (MD) simulations of small proteins provide insight into the mechanisms and... molecular dynamics (MD) and Langevin dynamics (LD) simulations for the prediction of thermodynamic folding observables of the Trp-cage mini-protein. All

Bridging the education-action gap: a near-peer case-based undergraduate ethics teaching programme.

PubMed

Kong, Wing May; Knight, Selena

2017-10-01

Undergraduate ethics teaching has made significant progress in the past decade, with evidence showing that students and trainee doctors feel more confident in identifying and analysing ethical issues. There is general consensus that ethics education should enable students and doctors to take ethically appropriate actions, and nurture moral integrity. However, the literature reports that doctors continue to find it difficult to take action when faced with perceived unethical behaviour. This has been evident in recent healthcare scandals, in which care has fallen below acceptable ethical standards, despite the presence of professional ethical guidelines and competencies. The National Foundation Training Programme forms the first 2 years of training for new UK doctors. We designed a Foundation Doctor (FD)-led teaching programme in which medical students were invited to bring cases and experiences from clinical placements for small group discussion facilitated by FDs. The aim was to enable students to act ethically in practice through developing moral sensitivity and moral identity, together with skills in ethical reasoning and tools to address barriers to taking ethical action. FDs were chosen as facilitators, based on the evidence that near-peer is an effective form of teaching in medicine and may provide positive role models for students. This article reviews the background rationale for the programme and its design. Important themes emerging from the case discussions are explored. Student and FD facilitator feedbacks are evaluated, and practical challenges to the implementation of this type of programme are discussed. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Reliability Sensitivity Analysis and Design Optimization of Composite Structures Based on Response Surface Methodology

NASA Technical Reports Server (NTRS)

Rais-Rohani, Masoud

2003-01-01

This report discusses the development and application of two alternative strategies in the form of global and sequential local response surface (RS) techniques for the solution of reliability-based optimization (RBO) problems. The problem of a thin-walled composite circular cylinder under axial buckling instability is used as a demonstrative example. In this case, the global technique uses a single second-order RS model to estimate the axial buckling load over the entire feasible design space (FDS) whereas the local technique uses multiple first-order RS models with each applied to a small subregion of FDS. Alternative methods for the calculation of unknown coefficients in each RS model are explored prior to the solution of the optimization problem. The example RBO problem is formulated as a function of 23 uncorrelated random variables that include material properties, thickness and orientation angle of each ply, cylinder diameter and length, as well as the applied load. The mean values of the 8 ply thicknesses are treated as independent design variables. While the coefficients of variation of all random variables are held fixed, the standard deviations of ply thicknesses can vary during the optimization process as a result of changes in the design variables. The structural reliability analysis is based on the first-order reliability method with reliability index treated as the design constraint. In addition to the probabilistic sensitivity analysis of reliability index, the results of the RBO problem are presented for different combinations of cylinder length and diameter and laminate ply patterns. The two strategies are found to produce similar results in terms of accuracy with the sequential local RS technique having a considerably better computational efficiency.

Novel Computational Protocols for Functionally Classifying and Characterising Serine Beta-Lactamases

PubMed Central

Das, Sayoni; Dawson, Natalie L.; Dobrijevic, Dragana; Orengo, Christine

2016-01-01

Beta-lactamases represent the main bacterial mechanism of resistance to beta-lactam antibiotics and are a significant challenge to modern medicine. We have developed an automated classification and analysis protocol that exploits structure- and sequence-based approaches and which allows us to propose a grouping of serine beta-lactamases that more consistently captures and rationalizes the existing three classification schemes: Classes, (A, C and D, which vary in their implementation of the mechanism of action); Types (that largely reflect evolutionary distance measured by sequence similarity); and Variant groups (which largely correspond with the Bush-Jacoby clinical groups). Our analysis platform exploits a suite of in-house and public tools to identify Functional Determinants (FDs), i.e. residue sites, responsible for conferring different phenotypes between different classes, different types and different variants. We focused on Class A beta-lactamases, the most highly populated and clinically relevant class, to identify FDs implicated in the distinct phenotypes associated with different Class A Types and Variants. We show that our FunFHMMer method can separate the known beta-lactamase classes and identify those positions likely to be responsible for the different implementations of the mechanism of action in these enzymes. Two novel algorithms, ASSP and SSPA, allow detection of FD sites likely to contribute to the broadening of the substrate profiles. Using our approaches, we recognise 151 Class A types in UniProt. Finally, we used our beta-lactamase FunFams and ASSP profiles to detect 4 novel Class A types in microbiome samples. Our platforms have been validated by literature studies, in silico analysis and some targeted experimental verification. Although developed for the serine beta-lactamases they could be used to classify and analyse any diverse protein superfamily where sub-families have diverged over both long and short evolutionary timescales. PMID:27332861

Sleep disorders in Charcot-Marie-Tooth disease type 1.

PubMed

Boentert, Matthias; Knop, Katharina; Schuhmacher, Christine; Gess, Burkhard; Okegwo, Angelika; Young, Peter

2014-03-01

Obstructive sleep apnoea (OSA) and restless legs syndrome (RLS) have been reported in Charcot-Marie-Tooth disease (CMT) type 1A and axonal subtypes of CMT, respectively. The aim of this case-control study was to investigate both prevalence and severity of OSA, RLS and periodic limb movements in sleep (PLMS) in adult patients with genetically proven CMT1. 61 patients with CMT1 and 61 insomnic control subjects were matched for age, sex, and Body Mass Index. Neurological disability in patients with CMT was assessed using the Functional Disability Scale (FDS). RLS diagnosis was based on a screening questionnaire and structured clinical interviews. All participants underwent overnight polysomnography. OSA was present in 37.7% of patients with CMT1 and 4.9% of controls (p<0.0001). The mean Apnoea Hypoponea Index (AHI) was significantly higher in patients with CMT1 than in control individuals (9.1/h vs 1.2/h). RLS was present in 40.9% of patients with CMT1 and in 16.4% of controls (p<0.001). In the CMT1 group, OSA was significantly more common in men and RLS in women. The AHI correlated with both age and the FDS score, the latter being a significant independent predictor of OSA. PLMS were found in 41.0% of patients with CMT1, but were not correlated with measures of sleep quality. In addition to known risk factors, CMT may predispose to OSA. RLS is highly prevalent not only in axonal subtypes of CMT but also in primarily demyelinating subforms of CMT. PLMS are common in CMT1, but do not significantly impair sleep quality.

Lifetime depression and anxiety increase prevalent psychological symptoms and worsen glycemic control in type 2 diabetes: The Fremantle Diabetes Study Phase II.

PubMed

Whitworth, S R; Bruce, D G; Starkstein, S E; Davis, W A; Davis, T M E; Bucks, R S

2016-12-01

To determine the contribution of lifetime major depressive disorder (L-MDD) and lifetime generalized anxiety disorder (L-GAD) to current psychological symptom severity, health behaviour and glycaemic control in type 2 diabetes. 1285 community-dwelling people with type 2 diabetes (Fremantle Diabetes Study Phase-II; FDS2) completed the PHQ-9 and Brief Life-Time Depression Scale (BLDS) to assess current and past MDD. The Generalized Anxiety Disorder Scale (GADS) and the Generalized Anxiety Disorder Scale-Lifetime (GAD-LT), designed for FDS2, assessed current and past anxiety. Data were analysed using analysis of covariance and multiple mediation models, controlling for age, gender, marital status, and diabetes duration. L-MDD and L-GAD were independently associated with more severe current depression (both P<0.001) and anxiety (both P<0.001) symptoms. Mediation models revealed that, through increasing the severity of current depressive symptoms, L-MDD was associated with higher HbA 1c and body mass index (BMI), greater likelihood of current smoking, and reduced self-monitoring of blood glucose (SMBG) (indirect regression path ab, all P<0.001). In combination, L-MDD+L-GAD additionally elevated the risk of higher HbA 1c and worse diabetes management, by increasing the severity of current depressive symptoms (indirect regression path ab, all P<0.001). Lifetime depression and anxiety increase risk of more severe psychological symptoms, hyperglycaemia, and difficulties with health behaviour in type 2 diabetes. Early screening for these disorders at diabetes diagnosis may be warranted to maximize long-term health outcomes. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Simultaneous determination of nickel and copper by H-point standard addition method-first-order derivative spectrophotometry in plant samples after separation and preconcentration on modified natural clinoptilolite as a new sorbent.

PubMed

Roohparvar, Rasool; Taher, Mohammad Ali; Mohadesi, Alireza

2008-01-01

For the simultaneous determination of nickel(ll) and copper(ll) in plant samples, a rapid and accurate method was developed. In this method, solid-phase extraction (SPE) and first-order derivative spectrophotometry (FDS) are combined, and the result is coupled with the H-point standard addition method (HPSAM). Compared with normal spectrophotometry, derivative spectrophotometry offers the advantages of increased selectivity and sensitivity. As there is no need for carrying out any pretreatment of the sample, the spectrophotometry method is easy, but because of a high detection limit, it is not so practical. In order to decrease the detection limit, it is suggested to combine spectrophotometry with a preconcentration method such as SPE. In the present work, after separation and preconcentration of Ni(ll) and Cu(ll) on modified clinoptilolite zeolite that is loaded with 2-[1-(2-hydroxy-5-sulforphenyl)-3-phenyl-5-formaza-no]-benzoic acid monosodium salt (zincon) as a selective chromogenic reagent, FDS-HPSAM, which is a simple and selective spectrophotometric method, has been applied for simultaneous determination of these ions. With optimum conditions, the detection limit in original solutions is 0.7 and 0.5 ng/mL, respectively, for nickel and copper. The linear concentration ranges in the proposed method for nickel and copper ions in original solutions are 1.1 to 3.0 x 10(3) and 0.9 to 2.0 x 10(3) ng/mL, respectively. The recommended procedure is applied to successful determination of Cu(ll) and Ni(ll) in standard and real samples.

THE SPITZER INFRARED SPECTROGRAPH SURVEY OF PROTOPLANETARY DISKS IN ORION A. I. DISK PROPERTIES

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

Kim, K. H.; Watson, Dan M.; Manoj, P.

2016-09-01

We present our investigation of 319 Class II objects in Orion A observed by Spitzer /IRS. We also present the follow-up observations of 120 of these Class II objects in Orion A from the Infrared Telescope Facility/SpeX. We measure continuum spectral indices, equivalent widths, and integrated fluxes that pertain to disk structure and dust composition from IRS spectra of Class II objects in Orion A. We estimate mass accretion rates using hydrogen recombination lines in the SpeX spectra of our targets. Utilizing these properties, we compare the distributions of the disk and dust properties of Orion A disks with thosemore » of Taurus disks with respect to position within Orion A (Orion Nebular Cluster [ONC] and L1641) and with the subgroups by the inferred radial structures, such as transitional disks (TDs) versus radially continuous full disks (FDs). Our main findings are as follows. (1) Inner disks evolve faster than the outer disks. (2) The mass accretion rates of TDs and those of radially continuous FDs are statistically significantly displaced from each other. The median mass accretion rate of radially continuous disks in the ONC and L1641 is not very different from that in Taurus. (3) Less grain processing has occurred in the disks in the ONC compared to those in Taurus, based on analysis of the shape index of the 10 μ m silicate feature ( F {sub 11.3}/ F {sub 9.8}). (4) The 20–31 μ m continuum spectral index tracks the projected distance from the most luminous Trapezium star, θ {sup 1} Ori C. A possible explanation is UV ablation of the outer parts of disks.« less

Assessing post-fire ground cover in Mediterranean shrublands with field spectrometry and digital photography

NASA Astrophysics Data System (ADS)

Montorio Llovería, Raquel; Pérez-Cabello, Fernando; García-Martín, Alberto

2016-09-01

Fire severity can be assessed by identifying and quantifying the fractional abundance of post-fire ground cover types, an approach with great capacity to predict ecosystem response. Focused on shrubland formations of Mediterranean-type ecosystems, three burned areas (Ibieca and Zuera wildfires and Peñaflor experimental fire) were sampled in the summers of 2006 and 2007. Two different ground measurements were made for each of the 356 plots: (i) 3-band high spatial resolution photography (HSRP) and (ii) the hemispherical-conical reflectance factor (HCRF) in the visible to near-infrared spectral range (VNIR, 400-900 nm). Stepwise multiple lineal regression (SMLR) models were fitted to spectral variables (HCRF, first derivative spectra or FDS, and four absorption indices) to estimate the fractional cover of seven post-fire ground cover types (vegetation and soil - unburned and charred components - and ash - char and ash, individually and as a combined category). Models were developed and validated at the Peñaflor site (training, n = 217; validation, n = 88) and applied to the samples from the Ibieca and Zuera sites (n = 51). The best results were observed for the abundance estimations of green vegetation (Radj.20.70-0.90), unburned soil (Radj.20.40-0.75), and the combination of ashes (Radj.20.65-0.80). In comparison of spectral data, FDS outperforms reflectance or absorption data because of its higher accuracy levels and, importantly, its greater capacity to yield generalizable models. Future efforts should be made to improve the estimation of intermediate severity levels and upscaling the developed models. In the context of fire severity assessment, our study demonstrates the potential of hyperspectral data to estimate in a quick and objective manner post-fire ground cover fractions and thus provide valuable information to guide management responses.

Multiscale molecular dynamics simulations of rotary motor proteins.

PubMed

Ekimoto, Toru; Ikeguchi, Mitsunori

2018-04-01

Protein functions require specific structures frequently coupled with conformational changes. The scale of the structural dynamics of proteins spans from the atomic to the molecular level. Theoretically, all-atom molecular dynamics (MD) simulation is a powerful tool to investigate protein dynamics because the MD simulation is capable of capturing conformational changes obeying the intrinsically structural features. However, to study long-timescale dynamics, efficient sampling techniques and coarse-grained (CG) approaches coupled with all-atom MD simulations, termed multiscale MD simulations, are required to overcome the timescale limitation in all-atom MD simulations. Here, we review two examples of rotary motor proteins examined using free energy landscape (FEL) analysis and CG-MD simulations. In the FEL analysis, FEL is calculated as a function of reaction coordinates, and the long-timescale dynamics corresponding to conformational changes is described as transitions on the FEL surface. Another approach is the utilization of the CG model, in which the CG parameters are tuned using the fluctuation matching methodology with all-atom MD simulations. The long-timespan dynamics is then elucidated straightforwardly by using CG-MD simulations.

Look-ahead Dynamic Simulation

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

2015-10-20

Look-ahead dynamic simulation software system incorporates the high performance parallel computing technologies, significantly reduces the solution time for each transient simulation case, and brings the dynamic simulation analysis into on-line applications to enable more transparency for better reliability and asset utilization. It takes the snapshot of the current power grid status, functions in parallel computing the system dynamic simulation, and outputs the transient response of the power system in real time.

Measurement of the absolute branching fraction of Ds+ --> tau+ nutau decay.

PubMed

Ecklund, K M; Love, W; Savinov, V; Lopez, A; Mendez, H; Ramirez, J; Ge, J Y; Miller, D H; Shipsey, I P J; Xin, B; Adams, G S; Anderson, M; Cummings, J P; Danko, I; Hu, D; Moziak, B; Napolitano, J; He, Q; Insler, J; Muramatsu, H; Park, C S; Thorndike, E H; Yang, F; Artuso, M; Blusk, S; Khalil, S; Li, J; Mountain, R; Nisar, S; Randrianarivony, K; Sultana, N; Skwarnicki, T; Stone, S; Wang, J C; Zhang, L M; Bonvicini, G; Cinabro, D; Dubrovin, M; Lincoln, A; Rademacker, J; Asner, D M; Edwards, K W; Naik, P; Reed, J; Briere, R A; Ferguson, T; Tatishvili, G; Vogel, H; Watkins, M E; Rosner, J L; Alexander, J P; Cassel, D G; Duboscq, J E; Ehrlich, R; Fields, L; Gibbons, L; Gray, R; Gray, S W; Hartill, D L; Heltsley, B K; Hertz, D; Jones, C D; Kandaswamy, J; Kreinick, D L; Kuznetsov, V E; Mahlke-Krüger, H; Mohapatra, D; Onyisi, P U E; Patterson, J R; Peterson, D; Riley, D; Ryd, A; Sadoff, A J; Shi, X; Stroiney, S; Sun, W M; Wilksen, T; Athar, S B; Patel, R; Yelton, J; Rubin, P; Eisenstein, B I; Karliner, I; Mehrabyan, S; Lowrey, N; Selen, M; White, E J; Wiss, J; Mitchell, R E; Shepherd, M R; Besson, D; Pedlar, T K; Cronin-Hennessy, D; Gao, K Y; Hietala, J; Kubota, Y; Klein, T; Lang, B W; Poling, R; Scott, A W; Zweber, P; Dobbs, S; Metreveli, Z; Seth, K K; Tomaradze, A; Libby, J; Powell, A; Wilkinson, G

2008-04-25

Using a sample of tagged D(s)(+) decays collected near the D(s)(*+/-)D(s)(-/+) peak production energy in e(+)e(-) collisions with the CLEO-c detector, we study the leptonic decay D(s)(+)-->tau(+)nu(tau) via the decay channel tau(+)-->e(+)nu(e)nu(tau). We measure B(D(s)(+)-->tau(+)nu(tau))=(6.17+/-0.71+/-0.34)%, where the first error is statistical and the second systematic. Combining this result with our measurements of D(s)(+)-->mu(+)nu(mu) and D(s)(+)-->tau(+)nu(tau) (via tau(+)-->pi(+)nu(tau)), we determine f(D(s))=(274+/-10+/-5) MeV.

Integrated Design Analysis and Optimisation of Aircraft Structures (L’Analyse pour la Conception Integree et l’Optimisation des Structures d’Aeronefs)

DTIC Science & Technology

1992-02-01

Division (Code RM) ONERA Office of Aeronautics & Space Technology 29 ave de la Division Leclerc NASA Hq 92320 Chfitillon Washington DC 20546 France United...Vector of thickness variables. V’ = [ t2 ........ tN Vector of thickness changes. AV ’= [rt, 5t2 ......... tNJ TI 7-9 Vector of strain derivatives. F...ds, ds, I d, 1i’,= dt, dr2 ........ dt--N Vector of buckling derivatives. dX d). , dt1 dt2 dtN Then 5F= Vs’i . AV and SX V,’. AV The linearised

Energy spectrum of ultra-high energy cosmic rays observed with the Telescope Array using a hybrid technique

NASA Astrophysics Data System (ADS)

Abu-Zayyad, T.; Aida, R.; Allen, M.; Anderson, R.; Azuma, R.; Barcikowski, E.; Belz, J. W.; Bergman, D. R.; Blake, S. A.; Cady, R.; Cheon, B. G.; Chiba, J.; Chikawa, M.; Cho, E. J.; Cho, W. R.; Fujii, H.; Fujii, T.; Fukuda, T.; Fukushima, M.; Hanlon, W.; Hayashi, K.; Hayashi, Y.; Hayashida, N.; Hibino, K.; Hiyama, K.; Honda, K.; Iguchi, T.; Ikeda, D.; Ikuta, K.; Inoue, N.; Ishii, T.; Ishimori, R.; Ito, H.; Ivanov, D.; Iwamoto, S.; Jui, C. C. H.; Kadota, K.; Kakimoto, F.; Kalashev, O.; Kanbe, T.; Kasahara, K.; Kawai, H.; Kawakami, S.; Kawana, S.; Kido, E.; Kim, H. B.; Kim, H. K.; Kim, J. H.; Kim, J. H.; Kitamoto, K.; Kitamura, S.; Kitamura, Y.; Kobayashi, K.; Kobayashi, Y.; Kondo, Y.; Kuramoto, K.; Kuzmin, V.; Kwon, Y. J.; Lan, J.; Lim, S. I.; Lundquist, J. P.; Machida, S.; Martens, K.; Matsuda, T.; Matsuura, T.; Matsuyama, T.; Matthews, J. N.; Minamino, M.; Miyata, K.; Murano, Y.; Myers, I.; Nagasawa, K.; Nagataki, S.; Nakamura, T.; Nam, S. W.; Nonaka, T.; Ogio, S.; Ohnishi, M.; Ohoka, H.; Oki, K.; Oku, D.; Okuda, T.; Ono, M.; Oshima, A.; Ozawa, S.; Park, I. H.; Pshirkov, M. S.; Rodriguez, D. C.; Roh, S. Y.; Rubtsov, G.; Ryu, D.; Sagawa, H.; Sakurai, N.; Sampson, A. L.; Scott, L. M.; Shah, P. D.; Shibata, F.; Shibata, T.; Shimodaira, H.; Shin, B. K.; Shin, J. I.; Shirahama, T.; Smith, J. D.; Sokolsky, P.; Springer, R. W.; Stokes, B. T.; Stratton, S. R.; Stroman, T.; Suzuki, S.; Takahashi, Y.; Takeda, M.; Taketa, A.; Takita, M.; Tameda, Y.; Tanaka, H.; Tanaka, K.; Tanaka, M.; Thomas, S. B.; Thomson, G. B.; Tinyakov, P.; Tkachev, I.; Tokuno, H.; Tomida, T.; Troitsky, S.; Tsunesada, Y.; Tsutsumi, K.; Tsuyuguchi, Y.; Uchihori, Y.; Udo, S.; Ukai, H.; Urban, F.; Vasiloff, G.; Wada, Y.; Wong, T.; Yamakawa, Y.; Yamane, R.; Yamaoka, H.; Yamazaki, K.; Yang, J.; Yoneda, Y.; Yoshida, S.; Yoshii, H.; Zhou, X.; Zollinger, R.; Zundel, Z.

2015-02-01

We measure the spectrum of cosmic rays with energies greater than 1018.2 eV with the fluorescence detectors (FDs) and the surface detectors (SDs) of the Telescope Array Experiment using the data taken in our first 2.3-year observation from May 27, 2008 to September 7, 2010. A hybrid air shower reconstruction technique is employed to improve accuracies in determination of arrival directions and primary energies of cosmic rays using both FD and SD data. The energy spectrum presented here is in agreement with our previously published spectra and the HiRes results.

Molecular Dynamics Simulations of Folding and Insertion of the Ebola Virus Fusion Peptide into a Membrane Bilayer

DTIC Science & Technology

2008-07-01

Molecular Dynamics Simulations of Folding and Insertion of the Ebola Virus Fusion Peptide into a Membrane Bilayer Mark A. Olson1, In...presents replica-exchange molecular dynamics simulations of the folding and insertion of a 16- residue Ebola virus fusion peptide into a membrane...separate calculated structures into conformational basins. 2.1 Simulation models Molecular dynamics simulations were performed using the all-atom

Quasi-Dynamic Versus Fully-Dynamic Simulations of Slip Accumulation on Faults with Enhanced Dynamic Weakening

NASA Astrophysics Data System (ADS)

Lapusta, N.; Thomas, M.; Noda, H.; Avouac, J.

2012-12-01

Long-term simulations that incorporate both seismic events and aseismic slip are quite important for studies of earthquake physics but challenging computationally. To study long deformation histories, most simulation methods do not incorporate full inertial effects (wave propagation) during simulated earthquakes, using quasi-dynamic approximations instead. Here we compare the results of quasi-dynamic simulations to the fully dynamic ones for a range of problems to determine the applicability of the quasi-dynamic approach. Intuitively, the quasi-dynamic approach should do relatively well in problems where wave-mediated effects are relatively simple but should have substantially different (and hence wrong) response when the wave-mediated stress transfers dominate the character of the seismic events. This is exactly what we observe in our simulations. We consider a 2D model of a rate-and-state fault with a seismogenic (steady-state velocity-weakening) zone surrounded by creeping (steady-state velocity-strengthening) areas. If the seismogenic zone is described by the standard Dieterich-Ruina rate-and-state friction, the resulting earthquake sequences consist of relatively simple crack-like ruptures, and the inclusion of true wave-propagation effects mostly serves to concentrate stress more efficiently at the rupture front. Hence, in such models, rupture speeds and slip rates are significantly (several times) lower in the quasi-dynamic simulations compared to the fully dynamic ones, but the total slip, the crack-like nature of seismic events, and the overall pattern of earthquake sequences is comparable, consistently with prior studies. Such behavior can be classified as qualitatively similar but quantitatively different, and it motivates the popularity of the quasi-dynamic methods in simulations. However, the comparison changes dramatically once we consider a model with enhanced dynamic weakening in the seismogenic zone in the form of flash heating. In this case, the fully dynamic simulations produce seismic ruptures in the form of short-duration slip pulses, where the pulses form due to a combination of enhanced weakening and wave effects. The quasi-dynamic simulations in the same model produce completely different results, with large crack-like ruptures, different total slips, different rupture patterns, and different prestress state before large, model-spanning events. Such qualitative differences between the quasi-dynamic and fully-dynamic simulation should result in any model where inertial effects lead to qualitative differences, such as cases with supershear transition or fault with different materials on the two sides. We will present results on our current work on how the quasi-dynamic and fully dynamic simulations compare for the cases with heterogeneous fault properties.

Mapping Conformational Dynamics of Proteins Using Torsional Dynamics Simulations

PubMed Central

Gangupomu, Vamshi K.; Wagner, Jeffrey R.; Park, In-Hee; Jain, Abhinandan; Vaidehi, Nagarajan

2013-01-01

All-atom molecular dynamics simulations are widely used to study the flexibility of protein conformations. However, enhanced sampling techniques are required for simulating protein dynamics that occur on the millisecond timescale. In this work, we show that torsional molecular dynamics simulations enhance protein conformational sampling by performing conformational search in the low-frequency torsional degrees of freedom. In this article, we use our recently developed torsional-dynamics method called Generalized Newton-Euler Inverse Mass Operator (GNEIMO) to study the conformational dynamics of four proteins. We investigate the use of the GNEIMO method in simulations of the conformationally flexible proteins fasciculin and calmodulin, as well as the less flexible crambin and bovine pancreatic trypsin inhibitor. For the latter two proteins, the GNEIMO simulations with an implicit-solvent model reproduced the average protein structural fluctuations and sample conformations similar to those from Cartesian simulations with explicit solvent. The application of GNEIMO with replica exchange to the study of fasciculin conformational dynamics produced sampling of two of this protein’s experimentally established conformational substates. Conformational transition of calmodulin from the Ca2+-bound to the Ca2+-free conformation occurred readily with GNEIMO simulations. Moreover, the GNEIMO method generated an ensemble of conformations that satisfy about half of both short- and long-range interresidue distances obtained from NMR structures of holo to apo transitions in calmodulin. Although unconstrained all-atom Cartesian simulations have failed to sample transitions between the substates of fasciculin and calmodulin, GNEIMO simulations show the transitions in both systems. The relatively short simulation times required to capture these long-timescale conformational dynamics indicate that GNEIMO is a promising molecular-dynamics technique for studying domain motion in proteins. PMID:23663843

Mapping conformational dynamics of proteins using torsional dynamics simulations.

PubMed

Gangupomu, Vamshi K; Wagner, Jeffrey R; Park, In-Hee; Jain, Abhinandan; Vaidehi, Nagarajan

2013-05-07

All-atom molecular dynamics simulations are widely used to study the flexibility of protein conformations. However, enhanced sampling techniques are required for simulating protein dynamics that occur on the millisecond timescale. In this work, we show that torsional molecular dynamics simulations enhance protein conformational sampling by performing conformational search in the low-frequency torsional degrees of freedom. In this article, we use our recently developed torsional-dynamics method called Generalized Newton-Euler Inverse Mass Operator (GNEIMO) to study the conformational dynamics of four proteins. We investigate the use of the GNEIMO method in simulations of the conformationally flexible proteins fasciculin and calmodulin, as well as the less flexible crambin and bovine pancreatic trypsin inhibitor. For the latter two proteins, the GNEIMO simulations with an implicit-solvent model reproduced the average protein structural fluctuations and sample conformations similar to those from Cartesian simulations with explicit solvent. The application of GNEIMO with replica exchange to the study of fasciculin conformational dynamics produced sampling of two of this protein's experimentally established conformational substates. Conformational transition of calmodulin from the Ca(2+)-bound to the Ca(2+)-free conformation occurred readily with GNEIMO simulations. Moreover, the GNEIMO method generated an ensemble of conformations that satisfy about half of both short- and long-range interresidue distances obtained from NMR structures of holo to apo transitions in calmodulin. Although unconstrained all-atom Cartesian simulations have failed to sample transitions between the substates of fasciculin and calmodulin, GNEIMO simulations show the transitions in both systems. The relatively short simulation times required to capture these long-timescale conformational dynamics indicate that GNEIMO is a promising molecular-dynamics technique for studying domain motion in proteins. Copyright © 2013 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Metrics for comparing dynamic earthquake rupture simulations

USGS Publications Warehouse

Barall, Michael; Harris, Ruth A.

2014-01-01

Earthquakes are complex events that involve a myriad of interactions among multiple geologic features and processes. One of the tools that is available to assist with their study is computer simulation, particularly dynamic rupture simulation. A dynamic rupture simulation is a numerical model of the physical processes that occur during an earthquake. Starting with the fault geometry, friction constitutive law, initial stress conditions, and assumptions about the condition and response of the near‐fault rocks, a dynamic earthquake rupture simulation calculates the evolution of fault slip and stress over time as part of the elastodynamic numerical solution (Ⓔ see the simulation description in the electronic supplement to this article). The complexity of the computations in a dynamic rupture simulation make it challenging to verify that the computer code is operating as intended, because there are no exact analytic solutions against which these codes’ results can be directly compared. One approach for checking if dynamic rupture computer codes are working satisfactorily is to compare each code’s results with the results of other dynamic rupture codes running the same earthquake simulation benchmark. To perform such a comparison consistently, it is necessary to have quantitative metrics. In this paper, we present a new method for quantitatively comparing the results of dynamic earthquake rupture computer simulation codes.

Rotational Brownian Dynamics simulations of clathrin cage formation

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

Ilie, Ioana M.; Briels, Wim J.; MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede

2014-08-14

The self-assembly of nearly rigid proteins into ordered aggregates is well suited for modeling by the patchy particle approach. Patchy particles are traditionally simulated using Monte Carlo methods, to study the phase diagram, while Brownian Dynamics simulations would reveal insights into the assembly dynamics. However, Brownian Dynamics of rotating anisotropic particles gives rise to a number of complications not encountered in translational Brownian Dynamics. We thoroughly test the Rotational Brownian Dynamics scheme proposed by Naess and Elsgaeter [Macromol. Theory Simul. 13, 419 (2004); Naess and Elsgaeter Macromol. Theory Simul. 14, 300 (2005)], confirming its validity. We then apply the algorithmmore » to simulate a patchy particle model of clathrin, a three-legged protein involved in vesicle production from lipid membranes during endocytosis. Using this algorithm we recover time scales for cage assembly comparable to those from experiments. We also briefly discuss the undulatory dynamics of the polyhedral cage.« less

Molecular dynamics simulations of large macromolecular complexes.

PubMed

Perilla, Juan R; Goh, Boon Chong; Cassidy, C Keith; Liu, Bo; Bernardi, Rafael C; Rudack, Till; Yu, Hang; Wu, Zhe; Schulten, Klaus

2015-04-01

Connecting dynamics to structural data from diverse experimental sources, molecular dynamics simulations permit the exploration of biological phenomena in unparalleled detail. Advances in simulations are moving the atomic resolution descriptions of biological systems into the million-to-billion atom regime, in which numerous cell functions reside. In this opinion, we review the progress, driven by large-scale molecular dynamics simulations, in the study of viruses, ribosomes, bioenergetic systems, and other diverse applications. These examples highlight the utility of molecular dynamics simulations in the critical task of relating atomic detail to the function of supramolecular complexes, a task that cannot be achieved by smaller-scale simulations or existing experimental approaches alone. Copyright © 2015 Elsevier Ltd. All rights reserved.

The Development and Comparison of Molecular Dynamics Simulation and Monte Carlo Simulation

NASA Astrophysics Data System (ADS)

Chen, Jundong

2018-03-01

Molecular dynamics is an integrated technology that combines physics, mathematics and chemistry. Molecular dynamics method is a computer simulation experimental method, which is a powerful tool for studying condensed matter system. This technique not only can get the trajectory of the atom, but can also observe the microscopic details of the atomic motion. By studying the numerical integration algorithm in molecular dynamics simulation, we can not only analyze the microstructure, the motion of particles and the image of macroscopic relationship between them and the material, but can also study the relationship between the interaction and the macroscopic properties more conveniently. The Monte Carlo Simulation, similar to the molecular dynamics, is a tool for studying the micro-molecular and particle nature. In this paper, the theoretical background of computer numerical simulation is introduced, and the specific methods of numerical integration are summarized, including Verlet method, Leap-frog method and Velocity Verlet method. At the same time, the method and principle of Monte Carlo Simulation are introduced. Finally, similarities and differences of Monte Carlo Simulation and the molecular dynamics simulation are discussed.

Convergence and reproducibility in molecular dynamics simulations of the DNA duplex d(GCACGAACGAACGAACGC).

PubMed

Galindo-Murillo, Rodrigo; Roe, Daniel R; Cheatham, Thomas E

2015-05-01

The structure and dynamics of DNA are critically related to its function. Molecular dynamics simulations augment experiment by providing detailed information about the atomic motions. However, to date the simulations have not been long enough for convergence of the dynamics and structural properties of DNA. Molecular dynamics simulations performed with AMBER using the ff99SB force field with the parmbsc0 modifications, including ensembles of independent simulations, were compared to long timescale molecular dynamics performed with the specialized Anton MD engine on the B-DNA structure d(GCACGAACGAACGAACGC). To assess convergence, the decay of the average RMSD values over longer and longer time intervals was evaluated in addition to assessing convergence of the dynamics via the Kullback-Leibler divergence of principal component projection histograms. These molecular dynamics simulations-including one of the longest simulations of DNA published to date at ~44μs-surprisingly suggest that the structure and dynamics of the DNA helix, neglecting the terminal base pairs, are essentially fully converged on the ~1-5μs timescale. We can now reproducibly converge the structure and dynamics of B-DNA helices, omitting the terminal base pairs, on the μs time scale with both the AMBER and CHARMM C36 nucleic acid force fields. Results from independent ensembles of simulations starting from different initial conditions, when aggregated, match the results from long timescale simulations on the specialized Anton MD engine. With access to large-scale GPU resources or the specialized MD engine "Anton" it is possible for a variety of molecular systems to reproducibly and reliably converge the conformational ensemble of sampled structures. This article is part of a Special Issue entitled: Recent developments of molecular dynamics. Copyright © 2014. Published by Elsevier B.V.

Faster than Real-Time Dynamic Simulation for Large-Size Power System with Detailed Dynamic Models using High-Performance Computing Platform

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

Huang, Renke; Jin, Shuangshuang; Chen, Yousu

This paper presents a faster-than-real-time dynamic simulation software package that is designed for large-size power system dynamic simulation. It was developed on the GridPACKTM high-performance computing (HPC) framework. The key features of the developed software package include (1) faster-than-real-time dynamic simulation for a WECC system (17,000 buses) with different types of detailed generator, controller, and relay dynamic models, (2) a decoupled parallel dynamic simulation algorithm with optimized computation architecture to better leverage HPC resources and technologies, (3) options for HPC-based linear and iterative solvers, (4) hidden HPC details, such as data communication and distribution, to enable development centered on mathematicalmore » models and algorithms rather than on computational details for power system researchers, and (5) easy integration of new dynamic models and related algorithms into the software package.« less

Swarm Counter-Asymmetric-Threat (CAT) 6-DOF Dynamics Simulation

DTIC Science & Technology

2005-07-01

NAWCWD TP 8593 Swarm Counter-Asymmetric-Threat ( CAT ) 6-DOF Dynamics Simulation by James Bobinchak Weapons and Energetics...mathematical models used in the swarm counter- asymmetric-threat ( CAT ) simulation and the results of extensive Monte Carlo simulations. The swarm CAT ...Asymmetric-Threat ( CAT ) 6-DOF Dynamics Simulation (U) 6. AUTHOR(S) James Bobinchak and Gary Hewer 7. PERFORMING ORGANIZATION NAME(S) AND

Membrane Insertion Profiles of Peptides Probed by Molecular Dynamics Simulations

DTIC Science & Technology

2008-07-17

Membrane insertion profiles of peptides probed by molecular dynamics simulations In-Chul Yeh,* Mark A. Olson,# Michael S. Lee,*#§ and Anders...a methodology based on molecular dynamics simulation techniques to probe the insertion profiles of small peptides across the membrane interface. The...profiles of peptides probed by molecular dynamics simulations 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d

Efficient Conformational Sampling in Explicit Solvent Using a Hybrid Replica Exchange Molecular Dynamics Method

DTIC Science & Technology

2011-12-01

REMD while reproducing the energy landscape of explicit solvent simulations . ’ INTRODUCTION Molecular dynamics (MD) simulations of proteins can pro...Mongan, J.; McCammon, J. A. Accelerated molecular dynamics : a promising and efficient simulation method for biomolecules. J. Chem. Phys. 2004, 120 (24...Chemical Theory and Computation ARTICLE (8) Abraham,M. J.; Gready, J. E. Ensuringmixing efficiency of replica- exchange molecular dynamics simulations . J

Validation of the train energy and dynamics simulator (TEDS).

DOT National Transportation Integrated Search

2015-01-01

FRA has developed Train Energy and Dynamics Simulator (TEDS) based upon a longitudinal train dynamics and operations : simulation model which allows users to conduct safety and risk evaluations, incident investigations, studies of train operations, :...

Molecular dynamics simulations of thermally activated edge dislocation unpinning from voids in α -Fe

NASA Astrophysics Data System (ADS)

Byggmästar, J.; Granberg, F.; Nordlund, K.

2017-10-01

In this study, thermal unpinning of edge dislocations from voids in α -Fe is investigated by means of molecular dynamics simulations. The activation energy as a function of shear stress and temperature is systematically determined. Simulations with a constant applied stress are compared with dynamic simulations with a constant strain rate. We found that a constant applied stress results in a temperature-dependent activation energy. The temperature dependence is attributed to the elastic softening of iron. If the stress is normalized with the softening of the specific shear modulus, the activation energy is shown to be temperature-independent. From the dynamic simulations, the activation energy as a function of critical shear stress was determined using previously developed methods. The results from the dynamic simulations are in good agreement with the constant stress simulations, after the normalization. This indicates that the computationally more efficient dynamic method can be used to obtain the activation energy as a function of stress and temperature. The obtained relation between stress, temperature, and activation energy can be used to introduce a stochastic unpinning event in larger-scale simulation methods, such as discrete dislocation dynamics.

MCC level C formulation requirements. Shuttle TAEM guidance and flight control, STS-1 baseline

NASA Technical Reports Server (NTRS)

Carman, G. L.; Montez, M. N.

1980-01-01

The TAEM guidance and body rotational dynamics models required for the MCC simulation of the TAEM mission phase are defined. This simulation begins at the end of the entry phase and terminates at TAEM autoland interface. The logic presented is the required configuration for the first shuttle orbital flight (STS-1). The TAEM guidance is simulated in detail. The rotational dynamics simulation is a simplified model that assumes that the commanded rotational rates can be achieved in the integration interval. Thus, the rotational dynamics simulation is essentially a simulation of the autopilot commanded rates and integration of these rates to determine orbiter attitude. The rotational dynamics simulation also includes a simulation of the speedbrake deflection. The body flap and elevon deflections are computed in the orbiter aerodynamic simulation.

Experimental verification of dynamic simulation

NASA Technical Reports Server (NTRS)

Yae, K. Harold; Hwang, Howyoung; Chern, Su-Tai

1989-01-01

The dynamics model here is a backhoe, which is a four degree of freedom manipulator from the dynamics standpoint. Two types of experiment are chosen that can also be simulated by a multibody dynamics simulation program. In the experiment, recorded were the configuration and force histories; that is, velocity and position, and force output and differential pressure change from the hydraulic cylinder, in the time domain. When the experimental force history is used as driving force in the simulation model, the forward dynamics simulation produces a corresponding configuration history. Then, the experimental configuration history is used in the inverse dynamics analysis to generate a corresponding force history. Therefore, two sets of configuration and force histories--one set from experiment, and the other from the simulation that is driven forward and backward with the experimental data--are compared in the time domain. More comparisons are made in regard to the effects of initial conditions, friction, and viscous damping.

[Brownian dynamics simulations of protein-protein interactions in photosynthetic electron transport chain].

PubMed

Khruschev, S S; Abaturova, A M; Diakonova, A N; Fedorov, V A; Ustinin, D M; Kovalenko, I B; Riznichenko, G Yu; Rubin, A B

2015-01-01

The application of Brownian dynamics for simulation of transient protein-protein interactions is reviewed. The review focuses on theoretical basics of Brownian dynamics method, its particular implementations, advantages and drawbacks of the method. The outlook for future development of Brownian dynamics-based simulation techniques is discussed. Special attention is given to analysis of Brownian dynamics trajectories. The second part of the review is dedicated to the role of Brownian dynamics simulations in studying photosynthetic electron transport. Interactions of mobile electron carriers (plastocyanin, cytochrome c6, and ferredoxin) with their reaction partners (cytochrome b6f complex, photosystem I, ferredoxin:NADP-reductase, and hydrogenase) are considered.

Measurement of the Absolute Branching Fraction of Ds+→τ+ντ Decay

NASA Astrophysics Data System (ADS)

Ecklund, K. M.; Love, W.; Savinov, V.; Lopez, A.; Mendez, H.; Ramirez, J.; Ge, J. Y.; Miller, D. H.; Shipsey, I. P. J.; Xin, B.; Adams, G. S.; Anderson, M.; Cummings, J. P.; Danko, I.; Hu, D.; Moziak, B.; Napolitano, J.; He, Q.; Insler, J.; Muramatsu, H.; Park, C. S.; Thorndike, E. H.; Yang, F.; Artuso, M.; Blusk, S.; Khalil, S.; Li, J.; Mountain, R.; Nisar, S.; Randrianarivony, K.; Sultana, N.; Skwarnicki, T.; Stone, S.; Wang, J. C.; Zhang, L. M.; Bonvicini, G.; Cinabro, D.; Dubrovin, M.; Lincoln, A.; Rademacker, J.; Asner, D. M.; Edwards, K. W.; Naik, P.; Reed, J.; Briere, R. A.; Ferguson, T.; Tatishvili, G.; Vogel, H.; Watkins, M. E.; Rosner, J. L.; Alexander, J. P.; Cassel, D. G.; Duboscq, J. E.; Ehrlich, R.; Fields, L.; Gibbons, L.; Gray, R.; Gray, S. W.; Hartill, D. L.; Heltsley, B. K.; Hertz, D.; Jones, C. D.; Kandaswamy, J.; Kreinick, D. L.; Kuznetsov, V. E.; Mahlke-Krüger, H.; Mohapatra, D.; Onyisi, P. U. E.; Patterson, J. R.; Peterson, D.; Riley, D.; Ryd, A.; Sadoff, A. J.; Shi, X.; Stroiney, S.; Sun, W. M.; Wilksen, T.; Athar, S. B.; Patel, R.; Yelton, J.; Rubin, P.; Eisenstein, B. I.; Karliner, I.; Mehrabyan, S.; Lowrey, N.; Selen, M.; White, E. J.; Wiss, J.; Mitchell, R. E.; Shepherd, M. R.; Besson, D.; Pedlar, T. K.; Cronin-Hennessy, D.; Gao, K. Y.; Hietala, J.; Kubota, Y.; Klein, T.; Lang, B. W.; Poling, R.; Scott, A. W.; Zweber, P.; Dobbs, S.; Metreveli, Z.; Seth, K. K.; Tomaradze, A.; Libby, J.; Powell, A.; Wilkinson, G.

2008-04-01

Using a sample of tagged Ds+ decays collected near the Ds*±Ds∓ peak production energy in e+e- collisions with the CLEO-c detector, we study the leptonic decay Ds+→τ+ντ via the decay channel τ+→e+νeν¯τ. We measure B(Ds+→τ+ντ)=(6.17±0.71±0.34)%, where the first error is statistical and the second systematic. Combining this result with our measurements of Ds+→μ+νμ and Ds+→τ+ντ (via τ+→π+ν¯τ), we determine fDs=(274±10±5)MeV.

International Space Station United States Laboratory Module Water Recovery Management Subsystem Verification from Flight 5A to Stage ULF2

NASA Technical Reports Server (NTRS)

Williams, David E.; Labuda, Laura

2009-01-01

The International Space Station (ISS) Environmental Control and Life Support (ECLS) system comprises of seven subsystems: Atmosphere Control and Supply (ACS), Atmosphere Revitalization (AR), Fire Detection and Suppression (FDS), Temperature and Humidity Control (THC), Vacuum System (VS), Water Recovery and Management (WRM), and Waste Management (WM). This paper provides a summary of the nominal operation of the United States (U.S.) Laboratory Module WRM design and detailed element methodologies utilized during the Qualification phase of the U.S. Laboratory Module prior to launch and the Qualification of all of the modification kits added to it from Flight 5A up and including Stage ULF2.

Implementation of Parallel Dynamic Simulation on Shared-Memory vs. Distributed-Memory Environments

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

Jin, Shuangshuang; Chen, Yousu; Wu, Di

2015-12-09

Power system dynamic simulation computes the system response to a sequence of large disturbance, such as sudden changes in generation or load, or a network short circuit followed by protective branch switching operation. It consists of a large set of differential and algebraic equations, which is computational intensive and challenging to solve using single-processor based dynamic simulation solution. High-performance computing (HPC) based parallel computing is a very promising technology to speed up the computation and facilitate the simulation process. This paper presents two different parallel implementations of power grid dynamic simulation using Open Multi-processing (OpenMP) on shared-memory platform, and Messagemore » Passing Interface (MPI) on distributed-memory clusters, respectively. The difference of the parallel simulation algorithms and architectures of the two HPC technologies are illustrated, and their performances for running parallel dynamic simulation are compared and demonstrated.« less

Toll-Like Receptor-9-Mediated Invasion in Breast Cancer

DTIC Science & Technology

2011-07-01

Molecular Dynamics Simulations. Theoretical structural models were obtained from molecular dynamics simulations using explicit solvation by...with AMBER by MARDIGRAS. The solution structure was then derived by coupling the resulting NMR distance restraints with a molecular dynamic ...Overlay of NMR restrained structure (red) with theoretical molecular dynamic simulated annealing structure (blue). Energetic stability of the 9-mer

Simulating Open Quantum Systems with Hamiltonian Ensembles and the Nonclassicality of the Dynamics

NASA Astrophysics Data System (ADS)

Chen, Hong-Bin; Gneiting, Clemens; Lo, Ping-Yuan; Chen, Yueh-Nan; Nori, Franco

2018-01-01

The incoherent dynamical properties of open quantum systems are generically attributed to an ongoing correlation between the system and its environment. Here, we propose a novel way to assess the nature of these system-environment correlations by examining the system dynamics alone. Our approach is based on the possibility or impossibility to simulate open-system dynamics with Hamiltonian ensembles. As we show, such (im)possibility to simulate is closely linked to the system-environment correlations. We thus define the nonclassicality of open-system dynamics in terms of the nonexistence of a Hamiltonian-ensemble simulation. This classifies any nonunital open-system dynamics as nonclassical. We give examples for open-system dynamics that are unital and classical, as well as unital and nonclassical.

Coupled binding-bending-folding: The complex conformational dynamics of protein-DNA binding studied by atomistic molecular dynamics simulations.

PubMed

van der Vaart, Arjan

2015-05-01

Protein-DNA binding often involves dramatic conformational changes such as protein folding and DNA bending. While thermodynamic aspects of this behavior are understood, and its biological function is often known, the mechanism by which the conformational changes occur is generally unclear. By providing detailed structural and energetic data, molecular dynamics simulations have been helpful in elucidating and rationalizing protein-DNA binding. This review will summarize recent atomistic molecular dynamics simulations of the conformational dynamics of DNA and protein-DNA binding. A brief overview of recent developments in DNA force fields is given as well. Simulations have been crucial in rationalizing the intrinsic flexibility of DNA, and have been instrumental in identifying the sequence of binding events, the triggers for the conformational motion, and the mechanism of binding for a number of important DNA-binding proteins. Molecular dynamics simulations are an important tool for understanding the complex binding behavior of DNA-binding proteins. With recent advances in force fields and rapid increases in simulation time scales, simulations will become even more important for future studies. This article is part of a Special Issue entitled Recent developments of molecular dynamics. Copyright © 2014. Published by Elsevier B.V.

Selecting a dynamic simulation modeling method for health care delivery research-part 2: report of the ISPOR Dynamic Simulation Modeling Emerging Good Practices Task Force.

PubMed

Marshall, Deborah A; Burgos-Liz, Lina; IJzerman, Maarten J; Crown, William; Padula, William V; Wong, Peter K; Pasupathy, Kalyan S; Higashi, Mitchell K; Osgood, Nathaniel D

2015-03-01

In a previous report, the ISPOR Task Force on Dynamic Simulation Modeling Applications in Health Care Delivery Research Emerging Good Practices introduced the fundamentals of dynamic simulation modeling and identified the types of health care delivery problems for which dynamic simulation modeling can be used more effectively than other modeling methods. The hierarchical relationship between the health care delivery system, providers, patients, and other stakeholders exhibits a level of complexity that ought to be captured using dynamic simulation modeling methods. As a tool to help researchers decide whether dynamic simulation modeling is an appropriate method for modeling the effects of an intervention on a health care system, we presented the System, Interactions, Multilevel, Understanding, Loops, Agents, Time, Emergence (SIMULATE) checklist consisting of eight elements. This report builds on the previous work, systematically comparing each of the three most commonly used dynamic simulation modeling methods-system dynamics, discrete-event simulation, and agent-based modeling. We review criteria for selecting the most suitable method depending on 1) the purpose-type of problem and research questions being investigated, 2) the object-scope of the model, and 3) the method to model the object to achieve the purpose. Finally, we provide guidance for emerging good practices for dynamic simulation modeling in the health sector, covering all aspects, from the engagement of decision makers in the model design through model maintenance and upkeep. We conclude by providing some recommendations about the application of these methods to add value to informed decision making, with an emphasis on stakeholder engagement, starting with the problem definition. Finally, we identify areas in which further methodological development will likely occur given the growing "volume, velocity and variety" and availability of "big data" to provide empirical evidence and techniques such as machine learning for parameter estimation in dynamic simulation models. Upon reviewing this report in addition to using the SIMULATE checklist, the readers should be able to identify whether dynamic simulation modeling methods are appropriate to address the problem at hand and to recognize the differences of these methods from those of other, more traditional modeling approaches such as Markov models and decision trees. This report provides an overview of these modeling methods and examples of health care system problems in which such methods have been useful. The primary aim of the report was to aid decisions as to whether these simulation methods are appropriate to address specific health systems problems. The report directs readers to other resources for further education on these individual modeling methods for system interventions in the emerging field of health care delivery science and implementation. Copyright © 2015. Published by Elsevier Inc.

A simple dynamic engine model for use in a real-time aircraft simulation with thrust vectoring

NASA Technical Reports Server (NTRS)

Johnson, Steven A.

1990-01-01

A simple dynamic engine model was developed at the NASA Ames Research Center, Dryden Flight Research Facility, for use in thrust vectoring control law development and real-time aircraft simulation. The simple dynamic engine model of the F404-GE-400 engine (General Electric, Lynn, Massachusetts) operates within the aircraft simulator. It was developed using tabular data generated from a complete nonlinear dynamic engine model supplied by the manufacturer. Engine dynamics were simulated using a throttle rate limiter and low-pass filter. Included is a description of a method to account for axial thrust loss resulting from thrust vectoring. In addition, the development of the simple dynamic engine model and its incorporation into the F-18 high alpha research vehicle (HARV) thrust vectoring simulation. The simple dynamic engine model was evaluated at Mach 0.2, 35,000 ft altitude and at Mach 0.7, 35,000 ft altitude. The simple dynamic engine model is within 3 percent of the steady state response, and within 25 percent of the transient response of the complete nonlinear dynamic engine model.

Dynamic Simulation over Long Time Periods with 100% Solar Generation.

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

Concepcion, Ricky James; Elliott, Ryan Thomas

2015-12-01

This project aimed to identify the path forward for dynamic simulation tools to accommodate these needs by characterizing the properties of power systems (with high PV penetration), analyzing how these properties affect dynamic simulation software, and offering solutions for potential problems.

Generalized Green's function molecular dynamics for canonical ensemble simulations

NASA Astrophysics Data System (ADS)

Coluci, V. R.; Dantas, S. O.; Tewary, V. K.

2018-05-01

The need of small integration time steps (˜1 fs) in conventional molecular dynamics simulations is an important issue that inhibits the study of physical, chemical, and biological systems in real timescales. Additionally, to simulate those systems in contact with a thermal bath, thermostating techniques are usually applied. In this work, we generalize the Green's function molecular dynamics technique to allow simulations within the canonical ensemble. By applying this technique to one-dimensional systems, we were able to correctly describe important thermodynamic properties such as the temperature fluctuations, the temperature distribution, and the velocity autocorrelation function. We show that the proposed technique also allows the use of time steps one order of magnitude larger than those typically used in conventional molecular dynamics simulations. We expect that this technique can be used in long-timescale molecular dynamics simulations.

Coupling all-atom molecular dynamics simulations of ions in water with Brownian dynamics.

PubMed

Erban, Radek

2016-02-01

Molecular dynamics (MD) simulations of ions (K + , Na + , Ca 2+ and Cl - ) in aqueous solutions are investigated. Water is described using the SPC/E model. A stochastic coarse-grained description for ion behaviour is presented and parametrized using MD simulations. It is given as a system of coupled stochastic and ordinary differential equations, describing the ion position, velocity and acceleration. The stochastic coarse-grained model provides an intermediate description between all-atom MD simulations and Brownian dynamics (BD) models. It is used to develop a multiscale method which uses all-atom MD simulations in parts of the computational domain and (less detailed) BD simulations in the remainder of the domain.

Molecular Dynamics Analysis of Lysozyme Protein in Ethanol- Water Mixed Solvent

DTIC Science & Technology

2012-01-01

molecular dynamics simulations of solvent effect on lysozyme protein, using water, ethanol, and different concentrations of water-ethanol mixtures as...understood. This work focuses on detailed molecular dynamics simulations of solvent effect on lysozyme protein, using water, ethanol, and different...using GROMACS molecular dynamics simulation (MD) code. Compared to water environment, the lysozyme structure showed remarkable changes in water

The Distributed Diagonal Force Decomposition Method for Parallelizing Molecular Dynamics Simulations

PubMed Central

Boršnik, Urban; Miller, Benjamin T.; Brooks, Bernard R.; Janežič, Dušanka

2011-01-01

Parallelization is an effective way to reduce the computational time needed for molecular dynamics simulations. We describe a new parallelization method, the distributed-diagonal force decomposition method, with which we extend and improve the existing force decomposition methods. Our new method requires less data communication during molecular dynamics simulations than replicated data and current force decomposition methods, increasing the parallel efficiency. It also dynamically load-balances the processors' computational load throughout the simulation. The method is readily implemented in existing molecular dynamics codes and it has been incorporated into the CHARMM program, allowing its immediate use in conjunction with the many molecular dynamics simulation techniques that are already present in the program. We also present the design of the Force Decomposition Machine, a cluster of personal computers and networks that is tailored to running molecular dynamics simulations using the distributed diagonal force decomposition method. The design is expandable and provides various degrees of fault resilience. This approach is easily adaptable to computers with Graphics Processing Units because it is independent of the processor type being used. PMID:21793007

A Force Balanced Fragmentation Method for ab Initio Molecular Dynamic Simulation of Protein.

PubMed

Xu, Mingyuan; Zhu, Tong; Zhang, John Z H

2018-01-01

A force balanced generalized molecular fractionation with conjugate caps (FB-GMFCC) method is proposed for ab initio molecular dynamic simulation of proteins. In this approach, the energy of the protein is computed by a linear combination of the QM energies of individual residues and molecular fragments that account for the two-body interaction of hydrogen bond between backbone peptides. The atomic forces on the caped H atoms were corrected to conserve the total force of the protein. Using this approach, ab initio molecular dynamic simulation of an Ace-(ALA) 9 -NME linear peptide showed the conservation of the total energy of the system throughout the simulation. Further a more robust 110 ps ab initio molecular dynamic simulation was performed for a protein with 56 residues and 862 atoms in explicit water. Compared with the classical force field, the ab initio molecular dynamic simulations gave better description of the geometry of peptide bonds. Although further development is still needed, the current approach is highly efficient, trivially parallel, and can be applied to ab initio molecular dynamic simulation study of large proteins.

Real-time electron dynamics for massively parallel excited-state simulations

NASA Astrophysics Data System (ADS)

Andrade, Xavier

The simulation of the real-time dynamics of electrons, based on time dependent density functional theory (TDDFT), is a powerful approach to study electronic excited states in molecular and crystalline systems. What makes the method attractive is its flexibility to simulate different kinds of phenomena beyond the linear-response regime, including strongly-perturbed electronic systems and non-adiabatic electron-ion dynamics. Electron-dynamics simulations are also attractive from a computational point of view. They can run efficiently on massively parallel architectures due to the low communication requirements. Our implementations of electron dynamics, based on the codes Octopus (real-space) and Qball (plane-waves), allow us to simulate systems composed of thousands of atoms and to obtain good parallel scaling up to 1.6 million processor cores. Due to the versatility of real-time electron dynamics and its parallel performance, we expect it to become the method of choice to apply the capabilities of exascale supercomputers for the simulation of electronic excited states.

Evaluation of a grid based molecular dynamics approach for polypeptide simulations.

PubMed

Merelli, Ivan; Morra, Giulia; Milanesi, Luciano

2007-09-01

Molecular dynamics is very important for biomedical research because it makes possible simulation of the behavior of a biological macromolecule in silico. However, molecular dynamics is computationally rather expensive: the simulation of some nanoseconds of dynamics for a large macromolecule such as a protein takes very long time, due to the high number of operations that are needed for solving the Newton's equations in the case of a system of thousands of atoms. In order to obtain biologically significant data, it is desirable to use high-performance computation resources to perform these simulations. Recently, a distributed computing approach based on replacing a single long simulation with many independent short trajectories has been introduced, which in many cases provides valuable results. This study concerns the development of an infrastructure to run molecular dynamics simulations on a grid platform in a distributed way. The implemented software allows the parallel submission of different simulations that are singularly short but together bring important biological information. Moreover, each simulation is divided into a chain of jobs to avoid data loss in case of system failure and to contain the dimension of each data transfer from the grid. The results confirm that the distributed approach on grid computing is particularly suitable for molecular dynamics simulations thanks to the elevated scalability.

Integration of Molecular Dynamics Based Predictions into the Optimization of De Novo Protein Designs: Limitations and Benefits.

PubMed

Carvalho, Henrique F; Barbosa, Arménio J M; Roque, Ana C A; Iranzo, Olga; Branco, Ricardo J F

2017-01-01

Recent advances in de novo protein design have gained considerable insight from the intrinsic dynamics of proteins, based on the integration of molecular dynamics simulations protocols on the state-of-the-art de novo protein design protocols used nowadays. With this protocol we illustrate how to set up and run a molecular dynamics simulation followed by a functional protein dynamics analysis. New users will be introduced to some useful open-source computational tools, including the GROMACS molecular dynamics simulation software package and ProDy for protein structural dynamics analysis.

Structure and Dynamics of End-to-End Loop Formation of the Penta-Peptide Cys-Ala-Gly-Gln-Trp in Implicit Solvents

DTIC Science & Technology

2009-01-01

implicit solvents on peptide structure and dynamics , we performed extensive molecular dynamics simulations on the penta-peptide Cys-Ala-Gly-Gln-Trp. Two...end-to-end distances and dihedral angles obtained from molecular dynamics simulations with implicit solvent models were in a good agreement with those...to maintain the temperature of the systems. Introduction Molecular dynamics (MD) simulation techniques are widely used to study structure and

Potent New Small-Molecule Inhibitor of Botulinum Neurotoxin Serotype A Endopeptidase Developed by Synthesis-Based Computer-Aided Molecular Design

DTIC Science & Technology

2009-11-01

dynamics of the complex predicted by multiple molecular dynamics simulations , and discuss further structural optimization to achieve better in vivo efficacy...complex with BoNTAe and the dynamics of the complex predicted by multiple molecular dynamics simulations (MMDSs). On the basis of the 3D model, we discuss...is unlimited whereas AHP exhibited 54% inhibition under the same conditions (Table 1). Computer Simulation Twenty different molecular dynamics

Preliminary neutronics design of china lead-alloy cooled demonstration reactor (CLEAR-III) for nuclear waste transmutation

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

Chen, Z.; Southwest Science and Technology Univ., No.350 Shushanhu Road, Shushan District, Hefei, Anhui, 230031; Chen, Y.

2012-07-01

China Lead-Alloy cooled Demonstration Reactor (CLEAR-III), which is the concept of lead-bismuth cooled accelerator driven sub-critical reactor for nuclear waste transmutation, was proposed and designed by FDS team in China. In this study, preliminary neutronics design studies have primarily focused on three important performance parameters including Transmutation Support Ratio (TSR), effective multiplication factor and blanket thermal power. The constraint parameters, such as power peaking factor and initial TRU loading, were also considered. In the specific design, uranium-free metallic dispersion fuel of (TRU-Zr)-Zr was used as one of the CLEAR-III fuel types and the ratio between MA and Pu was adjustedmore » to maximize transmutation ratio. In addition, three different fuel zones differing in the TRU fraction of the fuel were respectively employed for this subcritical reactor, and the zone sizes and TRU fractions were determined such that the linear powers of these zones were close to each other. The neutronics calculations and analyses were performed by using Multi-Functional 4D Neutronics Simulation System named VisualBUS and nuclear data library HENDL (Hybrid Evaluated Nuclear Data Library). In the preliminary design, the maximum TSRLLMA was {approx}11 and the blanket thermal power was {approx}1000 MW when the effective multiplication factor was 0.98. The results showed that good performance of transmutation could be achieved based on the subcritical reactor loaded with uranium-free fuel. (authors)« less

An Explicit Upwind Algorithm for Solving the Parabolized Navier-Stokes Equations

NASA Technical Reports Server (NTRS)

Korte, John J.

1991-01-01

An explicit, upwind algorithm was developed for the direct (noniterative) integration of the 3-D Parabolized Navier-Stokes (PNS) equations in a generalized coordinate system. The new algorithm uses upwind approximations of the numerical fluxes for the pressure and convection terms obtained by combining flux difference splittings (FDS) formed from the solution of an approximate Riemann (RP). The approximate RP is solved using an extension of the method developed by Roe for steady supersonic flow of an ideal gas. Roe's method is extended for use with the 3-D PNS equations expressed in generalized coordinates and to include Vigneron's technique of splitting the streamwise pressure gradient. The difficulty associated with applying Roe's scheme in the subsonic region is overcome. The second-order upwind differencing of the flux derivatives are obtained by adding FDS to either an original forward or backward differencing of the flux derivative. This approach is used to modify an explicit MacCormack differencing scheme into an upwind differencing scheme. The second order upwind flux approximations, applied with flux limiters, provide a method for numerically capturing shocks without the need for additional artificial damping terms which require adjustment by the user. In addition, a cubic equation is derived for determining Vegneron's pressure splitting coefficient using the updated streamwise flux vector. Decoding the streamwise flux vector with the updated value of Vigneron's pressure splitting improves the stability of the scheme. The new algorithm is applied to 2-D and 3-D supersonic and hypersonic laminar flow test cases. Results are presented for the experimental studies of Holden and of Tracy. In addition, a flow field solution is presented for a generic hypersonic aircraft at a Mach number of 24.5 and angle of attack of 1 degree. The computed results compare well to both experimental data and numerical results from other algorithms. Computational times required for the upwind PNS code are approximately equal to an explicit PNS MacCormack's code and existing implicit PNS solvers.

Refinement of myotome values in the upper limb: Evidence from brachial plexus injuries.

PubMed

Bell, S W; Brown, M J C; Hems, T J

2017-02-01

We reviewed patients with partial supraclavicular brachial plexus injuries in order to refine the myotome values of the upper limb. Forty-two patients with defined partial injuries to the supraclavicular brachial plexus were reviewed from a prospective database. The injuries patterns covered C5, C5-6, C5-7, C5-8, C7-T1 and C8-T1 roots. Upper plexus injuries were classified on the basis of surgical exploration and intraoperative stimulation and lower plexus injuries from MRI. Flexor Carpi Radialis (FCR) was paralyzed in C5-7 injuries, in addition to paralysis of deltoid, supraspinatus, infraspinatus and biceps, when compared to C5-6 injuries. Complete paralysis of Flexor Digitorum Profundus (FDP) and Flexor Digitorum Superficialis (FDS) to all digits was identified in C7-T1 injuries. In C5-8 injuries weakness was noted in FDP of ulnar digits and intrinsics innervated by the ulnar nerve, while in C8-T1 injuries paralysis was noted in the FDP to the radial digits. All patients with C8-T1 injuries had paralysis of FDS and the thenar muscles. In upper plexus injuries paralysis of FCR indicated involvement of C7 root in addition to C5 and C6 roots. The results provide new detail of innervation of muscles acting on the hand. Flexor muscles and intrinsic muscles of the thumb and radial fingers (median nerve) have an important contribution from T1, while for those acting on the ulnar digits (ulnar nerve) the main contribution is from C8 with some input from C7. T1 also gives consistent innervation to extensor pollicis longus. A revised myotome chart for the upper limb is proposed. Copyright © 2015 Royal College of Surgeons of Edinburgh (Scottish charity number SC005317) and Royal College of Surgeons in Ireland. Published by Elsevier Ltd. All rights reserved.

Quantitative interpretation of magnetic properties as a way to characterize biogeophysical signatures of biodegraded contaminated sites

NASA Astrophysics Data System (ADS)

Ustra, A.; Kessouri, P.; Leite, A.; Mendonça, C. A.; Bandeira, N.

2017-12-01

Magnetic minerals in soils and rocks are one way to study biogechemical and paleoenvironmental processes. The ultrafine fraction of these minerals (superparmagnetic (SP) and stable single domain (SSD)) are usually investigated in environmental magnetism studies, since changes in mineralogy, concentration, size and morphology of the magnetic grains can be related to biogeochemical processes. In this study, we use low-field frequency dependent susceptibility (FDS) and isothermal remanent magnetization (IRM) to characterize the magnetic properties of materials in environmental magnetism. Magnetic susceptibility (MS) measurements are frequently used as a proxy of magnetic minerals present in soils and rocks. MS is a complex function of magnetic mineralogy and grain size, as well as magnitude and frequency of the applied field. This work presents a method for inverting low-field FDS data. The inverted parameters can be interpreted in terms of grain size variations of magnetic particles on the SP-SSD transition. This work also presents a method for inverting IRM demagnetization curves, to obtain the saturation magnetization, the individual magnetic moment for an assemblage of ultrafine SP minerals and estimate the concentration of magnetic carriers. IRM magnetization curves can be interpreted as resulting from distinct contributions of different mineral phases, which can be described by Cummulative Log-Gaussian (CLG) distributions. Each acquisition curve provides fundamental parameters that are characteristic of the respective mineral phase. The CLG decomposition is widely used in an interpretation procedure named mineral unmixing. In this work we present an inversion method for mineral unmixing, implementing the genetic algorithm to find the parameters of distinct components. These methodologies have been tested by synthetic models and applied to data from environmental magnetism studies. In this work we apply the proposed methodologies to characterize the magnetic properties of samples from the former Brandywine MD Defense Reutilization and Marketing Office (DRMO). The results from the magnetic properties characterization will provide additional information that may assist the interpretation of the biogeophysical signatures observed at the site.

SU-E-J-191: Motion Prediction Using Extreme Learning Machine in Image Guided Radiotherapy

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

Jia, J; Cao, R; Pei, X

Purpose: Real-time motion tracking is a critical issue in image guided radiotherapy due to the time latency caused by image processing and system response. It is of great necessity to fast and accurately predict the future position of the respiratory motion and the tumor location. Methods: The prediction of respiratory position was done based on the positioning and tracking module in ARTS-IGRT system which was developed by FDS Team (www.fds.org.cn). An approach involving with the extreme learning machine (ELM) was adopted to predict the future respiratory position as well as the tumor’s location by training the past trajectories. For themore » training process, a feed-forward neural network with one single hidden layer was used for the learning. First, the number of hidden nodes was figured out for the single layered feed forward network (SLFN). Then the input weights and hidden layer biases of the SLFN were randomly assigned to calculate the hidden neuron output matrix. Finally, the predicted movement were obtained by applying the output weights and compared with the actual movement. Breathing movement acquired from the external infrared markers was used to test the prediction accuracy. And the implanted marker movement for the prostate cancer was used to test the implementation of the tumor motion prediction. Results: The accuracy of the predicted motion and the actual motion was tested. Five volunteers with different breathing patterns were tested. The average prediction time was 0.281s. And the standard deviation of prediction accuracy was 0.002 for the respiratory motion and 0.001 for the tumor motion. Conclusion: The extreme learning machine method can provide an accurate and fast prediction of the respiratory motion and the tumor location and therefore can meet the requirements of real-time tumor-tracking in image guided radiotherapy.« less

Investigation of the Dynamic Contact Angle Using a Direct Numerical Simulation Method.

PubMed

Zhu, Guangpu; Yao, Jun; Zhang, Lei; Sun, Hai; Li, Aifen; Shams, Bilal

2016-11-15

A large amount of residual oil, which exists as isolated oil slugs, remains trapped in reservoirs after water flooding. Numerous numerical studies are performed to investigate the fundamental flow mechanism of oil slugs to improve flooding efficiency. Dynamic contact angle models are usually introduced to simulate an accurate contact angle and meniscus displacement of oil slugs under a high capillary number. Nevertheless, in the oil slug flow simulation process, it is unnecessary to introduce the dynamic contact angle model because of a negligible change in the meniscus displacement after using the dynamic contact angle model when the capillary number is small. Therefore, a critical capillary number should be introduced to judge whether the dynamic contact model should be incorporated into simulations. In this study, a direct numerical simulation method is employed to simulate the oil slug flow in a capillary tube at the pore scale. The position of the interface between water and the oil slug is determined using the phase-field method. The capacity and accuracy of the model are validated using a classical benchmark: a dynamic capillary filling process. Then, different dynamic contact angle models and the factors that affect the dynamic contact angle are analyzed. The meniscus displacements of oil slugs with a dynamic contact angle and a static contact angle (SCA) are obtained during simulations, and the relative error between them is calculated automatically. The relative error limit has been defined to be 5%, beyond which the dynamic contact angle model needs to be incorporated into the simulation to approach the realistic displacement. Thus, the desired critical capillary number can be determined. A three-dimensional universal chart of critical capillary number, which functions as static contact angle and viscosity ratio, is given to provide a guideline for oil slug simulation. Also, a fitting formula is presented for ease of use.

A parameters optimization method for planar joint clearance model and its application for dynamics simulation of reciprocating compressor

NASA Astrophysics Data System (ADS)

Hai-yang, Zhao; Min-qiang, Xu; Jin-dong, Wang; Yong-bo, Li

2015-05-01

In order to improve the accuracy of dynamics response simulation for mechanism with joint clearance, a parameter optimization method for planar joint clearance contact force model was presented in this paper, and the optimized parameters were applied to the dynamics response simulation for mechanism with oversized joint clearance fault. By studying the effect of increased clearance on the parameters of joint clearance contact force model, the relation of model parameters between different clearances was concluded. Then the dynamic equation of a two-stage reciprocating compressor with four joint clearances was developed using Lagrange method, and a multi-body dynamic model built in ADAMS software was used to solve this equation. To obtain a simulated dynamic response much closer to that of experimental tests, the parameters of joint clearance model, instead of using the designed values, were optimized by genetic algorithms approach. Finally, the optimized parameters were applied to simulate the dynamics response of model with oversized joint clearance fault according to the concluded parameter relation. The dynamics response of experimental test verified the effectiveness of this application.

Conformational dynamics and internal friction in homopolymer globules: equilibrium vs. non-equilibrium simulations.

PubMed

Einert, T R; Sing, C E; Alexander-Katz, A; Netz, R R

2011-12-01

We study the conformational dynamics within homopolymer globules by solvent-implicit Brownian dynamics simulations. A strong dependence of the internal chain dynamics on the Lennard-Jones cohesion strength ε and the globule size N (G) is observed. We find two distinct dynamical regimes: a liquid-like regime (for ε < ε(s) with fast internal dynamics and a solid-like regime (for ε > ε(s) with slow internal dynamics. The cohesion strength ε(s) of this freezing transition depends on N (G) . Equilibrium simulations, where we investigate the diffusional chain dynamics within the globule, are compared with non-equilibrium simulations, where we unfold the globule by pulling the chain ends with prescribed velocity (encompassing low enough velocities so that the linear-response, viscous regime is reached). From both simulation protocols we derive the internal viscosity within the globule. In the liquid-like regime the internal friction increases continuously with ε and scales extensive in N (G) . This suggests an internal friction scenario where the entire chain (or an extensive fraction thereof) takes part in conformational reorganization of the globular structure.

Dynamic CFD Simulations of the Supersonic Inflatable Aerodynamic Decelerator (SIAD) Ballistic Range Tests

NASA Technical Reports Server (NTRS)

Brock, Joseph M; Stern, Eric

2016-01-01

Dynamic CFD simulations of the SIAD ballistic test model were performed using US3D flow solver. Motivation for performing these simulations is for the purpose of validation and verification of the US3D flow solver as a viable computational tool for predicting dynamic coefficients.

High performance computing in biology: multimillion atom simulations of nanoscale systems

PubMed Central

Sanbonmatsu, K. Y.; Tung, C.-S.

2007-01-01

Computational methods have been used in biology for sequence analysis (bioinformatics), all-atom simulation (molecular dynamics and quantum calculations), and more recently for modeling biological networks (systems biology). Of these three techniques, all-atom simulation is currently the most computationally demanding, in terms of compute load, communication speed, and memory load. Breakthroughs in electrostatic force calculation and dynamic load balancing have enabled molecular dynamics simulations of large biomolecular complexes. Here, we report simulation results for the ribosome, using approximately 2.64 million atoms, the largest all-atom biomolecular simulation published to date. Several other nanoscale systems with different numbers of atoms were studied to measure the performance of the NAMD molecular dynamics simulation program on the Los Alamos National Laboratory Q Machine. We demonstrate that multimillion atom systems represent a 'sweet spot' for the NAMD code on large supercomputers. NAMD displays an unprecedented 85% parallel scaling efficiency for the ribosome system on 1024 CPUs. We also review recent targeted molecular dynamics simulations of the ribosome that prove useful for studying conformational changes of this large biomolecular complex in atomic detail. PMID:17187988

ReaDDy - A Software for Particle-Based Reaction-Diffusion Dynamics in Crowded Cellular Environments

PubMed Central

Schöneberg, Johannes; Noé, Frank

2013-01-01

We introduce the software package ReaDDy for simulation of detailed spatiotemporal mechanisms of dynamical processes in the cell, based on reaction-diffusion dynamics with particle resolution. In contrast to other particle-based reaction kinetics programs, ReaDDy supports particle interaction potentials. This permits effects such as space exclusion, molecular crowding and aggregation to be modeled. The biomolecules simulated can be represented as a sphere, or as a more complex geometry such as a domain structure or polymer chain. ReaDDy bridges the gap between small-scale but highly detailed molecular dynamics or Brownian dynamics simulations and large-scale but little-detailed reaction kinetics simulations. ReaDDy has a modular design that enables the exchange of the computing core by efficient platform-specific implementations or dynamical models that are different from Brownian dynamics. PMID:24040218

Dynamic Mesh CFD Simulations of Orion Parachute Pendulum Motion During Atmospheric Entry

NASA Technical Reports Server (NTRS)

Halstrom, Logan D.; Schwing, Alan M.; Robinson, Stephen K.

2016-01-01

This paper demonstrates the usage of computational fluid dynamics to study the effects of pendulum motion dynamics of the NASAs Orion Multi-Purpose Crew Vehicle parachute system on the stability of the vehicles atmospheric entry and decent. Significant computational fluid dynamics testing has already been performed at NASAs Johnson Space Center, but this study sought to investigate the effect of bulk motion of the parachute, such as pitching, on the induced aerodynamic forces. Simulations were performed with a moving grid geometry oscillating according to the parameters observed in flight tests. As with the previous simulations, OVERFLOW computational fluid dynamics tool is used with the assumption of rigid, non-permeable geometry. Comparison to parachute wind tunnel tests is included for a preliminary validation of the dynamic mesh model. Results show qualitative differences in the flow fields of the static and dynamic simulations and quantitative differences in the induced aerodynamic forces, suggesting that dynamic mesh modeling of the parachute pendulum motion may uncover additional dynamic effects.

High Speed Civil Transport Aircraft Simulation: Reference-H Cycle 1, MATLAB Implementation

NASA Technical Reports Server (NTRS)

Sotack, Robert A.; Chowdhry, Rajiv S.; Buttrill, Carey S.

1999-01-01

The mathematical model and associated code to simulate a high speed civil transport aircraft - the Boeing Reference H configuration - are described. The simulation was constructed in support of advanced control law research. In addition to providing time histories of the dynamic response, the code includes the capabilities for calculating trim solutions and for generating linear models. The simulation relies on the nonlinear, six-degree-of-freedom equations which govern the motion of a rigid aircraft in atmospheric flight. The 1962 Standard Atmosphere Tables are used along with a turbulence model to simulate the Earth atmosphere. The aircraft model has three parts - an aerodynamic model, an engine model, and a mass model. These models use the data from the Boeing Reference H cycle 1 simulation data base. Models for the actuator dynamics, landing gear, and flight control system are not included in this aircraft model. Dynamic responses generated by the nonlinear simulation are presented and compared with results generated from alternate simulations at Boeing Commercial Aircraft Company and NASA Langley Research Center. Also, dynamic responses generated using linear models are presented and compared with dynamic responses generated using the nonlinear simulation.

Coarse-Grained Lattice Model Simulations of Sequence-Structure Fitness of a Ribosome-Inactivating Protein

DTIC Science & Technology

2007-11-05

limits of what is considered practical when applying all-atom molecular - dynamics simulation methods. Lattice models provide computationally robust...of expectation values from the density of states. All-atom molecular - dynamics simulations provide the most rigorous sampling method to generate con... molecular - dynamics simulations of protein folding,6–9 reported studies of computing a heat capacity or other calorimetric observables have been limited to

Quantum Fragment Based ab Initio Molecular Dynamics for Proteins.

PubMed

Liu, Jinfeng; Zhu, Tong; Wang, Xianwei; He, Xiao; Zhang, John Z H

2015-12-08

Developing ab initio molecular dynamics (AIMD) methods for practical application in protein dynamics is of significant interest. Due to the large size of biomolecules, applying standard quantum chemical methods to compute energies for dynamic simulation is computationally prohibitive. In this work, a fragment based ab initio molecular dynamics approach is presented for practical application in protein dynamics study. In this approach, the energy and forces of the protein are calculated by a recently developed electrostatically embedded generalized molecular fractionation with conjugate caps (EE-GMFCC) method. For simulation in explicit solvent, mechanical embedding is introduced to treat protein interaction with explicit water molecules. This AIMD approach has been applied to MD simulations of a small benchmark protein Trpcage (with 20 residues and 304 atoms) in both the gas phase and in solution. Comparison to the simulation result using the AMBER force field shows that the AIMD gives a more stable protein structure in the simulation, indicating that quantum chemical energy is more reliable. Importantly, the present fragment-based AIMD simulation captures quantum effects including electrostatic polarization and charge transfer that are missing in standard classical MD simulations. The current approach is linear-scaling, trivially parallel, and applicable to performing the AIMD simulation of proteins with a large size.

Dynamic system simulation of small satellite projects

NASA Astrophysics Data System (ADS)

Raif, Matthias; Walter, Ulrich; Bouwmeester, Jasper

2010-11-01

A prerequisite to accomplish a system simulation is to have a system model holding all necessary project information in a centralized repository that can be accessed and edited by all parties involved. At the Institute of Astronautics of the Technische Universitaet Muenchen a modular approach for modeling and dynamic simulation of satellite systems has been developed called dynamic system simulation (DySyS). DySyS is based on the platform independent description language SysML to model a small satellite project with respect to the system composition and dynamic behavior. A library of specific building blocks and possible relations between these blocks have been developed. From this library a system model of the satellite of interest can be created. A mapping into a C++ simulation allows the creation of an executable system model with which simulations are performed to observe the dynamic behavior of the satellite. In this paper DySyS is used to model and simulate the dynamic behavior of small satellites, because small satellite projects can act as a precursor to demonstrate the feasibility of a system model since they are less complex compared to a large scale satellite project.

Comparisons of Kinematics and Dynamics Simulation Software Tools

NASA Technical Reports Server (NTRS)

Shiue, Yeu-Sheng Paul

2002-01-01

Kinematic and dynamic analyses for moving bodies are essential to system engineers and designers in the process of design and validations. 3D visualization and motion simulation plus finite element analysis (FEA) give engineers a better way to present ideas and results. Marshall Space Flight Center (MSFC) system engineering researchers are currently using IGRIP from DELMIA Inc. as a kinematic simulation tool for discrete bodies motion simulations. Although IGRIP is an excellent tool for kinematic simulation with some dynamic analysis capabilities in robotic control, explorations of other alternatives with more powerful dynamic analysis and FEA capabilities are necessary. Kinematics analysis will only examine the displacement, velocity, and acceleration of the mechanism without considering effects from masses of components. With dynamic analysis and FEA, effects such as the forces or torques at the joint due to mass and inertia of components can be identified. With keen market competition, ALGOR Mechanical Event Simulation (MES), MSC visualNastran 4D, Unigraphics Motion+, and Pro/MECHANICA were chosen for explorations. In this study, comparisons between software tools were presented in terms of following categories: graphical user interface (GUI), import capability, tutorial availability, ease of use, kinematic simulation capability, dynamic simulation capability, FEA capability, graphical output, technical support, and cost. Propulsion Test Article (PTA) with Fastrac engine model exported from IGRIP and an office chair mechanism were used as examples for simulations.

Mosquito population dynamics from cellular automata-based simulation

NASA Astrophysics Data System (ADS)

Syafarina, Inna; Sadikin, Rifki; Nuraini, Nuning

2016-02-01

In this paper we present an innovative model for simulating mosquito-vector population dynamics. The simulation consist of two stages: demography and dispersal dynamics. For demography simulation, we follow the existing model for modeling a mosquito life cycles. Moreover, we use cellular automata-based model for simulating dispersal of the vector. In simulation, each individual vector is able to move to other grid based on a random walk. Our model is also capable to represent immunity factor for each grid. We simulate the model to evaluate its correctness. Based on the simulations, we can conclude that our model is correct. However, our model need to be improved to find a realistic parameters to match real data.

Tethered satellite system dynamics and control

NASA Technical Reports Server (NTRS)

Musetti, B.; Cibrario, B.; Bussolino, L.; Bodley, C. S.; Flanders, H. A.; Mowery, D. K.; Tomlin, D. D.

1990-01-01

The first tethered satellite system, scheduled for launch in May 1991, is reviewed. The system dynamics, dynamics control, and dynamics simulations are discussed. Particular attention is given to in-plane and out-of-plane librations; tether oscillation modes; orbiter and sub-satellite dynamics; deployer control system; the sub-satellite attitude measurement and control system; the Aeritalia Dynamics Model; the Martin-Marietta and NASA-MSFC Dynamics Model; and simulation results.

Numerical Simulation of Rolling-Airframes Using a Multi-Level Cartesian Method

NASA Technical Reports Server (NTRS)

Murman, Scott M.; Aftosmis, Michael J.; Berger, Marsha J.; Kwak, Dochan (Technical Monitor)

2002-01-01

A supersonic rolling missile with two synchronous canard control surfaces is analyzed using an automated, inviscid, Cartesian method. Sequential-static and time-dependent dynamic simulations of the complete motion are computed for canard dither schedules for level flight, pitch, and yaw maneuver. The dynamic simulations are compared directly against both high-resolution viscous simulations and relevant experimental data, and are also utilized to compute dynamic stability derivatives. The results show that both the body roll rate and canard dither motion influence the roll-averaged forces and moments on the body. At the relatively, low roll rates analyzed in the current work these dynamic effects are modest, however the dynamic computations are effective in predicting the dynamic stability derivatives which can be significant for highly-maneuverable missiles.

Analysis, simulation and visualization of 1D tapping via reduced dynamical models

NASA Astrophysics Data System (ADS)

Blackmore, Denis; Rosato, Anthony; Tricoche, Xavier; Urban, Kevin; Zou, Luo

2014-04-01

A low-dimensional center-of-mass dynamical model is devised as a simplified means of approximately predicting some important aspects of the motion of a vertical column comprised of a large number of particles subjected to gravity and periodic vertical tapping. This model is investigated first as a continuous dynamical system using analytical, simulation and visualization techniques. Then, by employing an approach analogous to that used to approximate the dynamics of a bouncing ball on an oscillating flat plate, it is modeled as a discrete dynamical system and analyzed to determine bifurcations and transitions to chaotic motion along with other properties. The predictions of the analysis are then compared-primarily qualitatively-with visualization and simulation results of the reduced continuous model, and ultimately with simulations of the complete system dynamics.

A CONTINUUM HARD-SPHERE MODEL OF PROTEIN ADSORPTION

PubMed Central

Finch, Craig; Clarke, Thomas; Hickman, James J.

2012-01-01

Protein adsorption plays a significant role in biological phenomena such as cell-surface interactions and the coagulation of blood. Two-dimensional random sequential adsorption (RSA) models are widely used to model the adsorption of proteins on solid surfaces. Continuum equations have been developed so that the results of RSA simulations can be used to predict the kinetics of adsorption. Recently, Brownian dynamics simulations have become popular for modeling protein adsorption. In this work a continuum model was developed to allow the results from a Brownian dynamics simulation to be used as the boundary condition in a computational fluid dynamics (CFD) simulation. Brownian dynamics simulations were used to model the diffusive transport of hard-sphere particles in a liquid and the adsorption of the particles onto a solid surface. The configuration of the adsorbed particles was analyzed to quantify the chemical potential near the surface, which was found to be a function of the distance from the surface and the fractional surface coverage. The near-surface chemical potential was used to derive a continuum model of adsorption that incorporates the results from the Brownian dynamics simulations. The equations of the continuum model were discretized and coupled to a CFD simulation of diffusive transport to the surface. The kinetics of adsorption predicted by the continuum model closely matched the results from the Brownian dynamics simulation. This new model allows the results from mesoscale simulations to be incorporated into micro- or macro-scale CFD transport simulations of protein adsorption in practical devices. PMID:23729843

Advanced Polymer Network Structures

DTIC Science & Technology

2016-02-01

double networks in a single step was identified from coarse-grained molecular dynamics simulations of polymer solvents bearing rigid side chains dissolved...in a polymer network. Coarse-grained molecular dynamics simulations also explored the mechanical behavior of traditional double networks and...DRI), polymer networks, polymer gels, molecular dynamics simulations , double networks 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF

A cable-driven parallel robots application: modelling and simulation of a dynamic cable model in Dymola

NASA Astrophysics Data System (ADS)

Othman, M. F.; Kurniawan, R.; Schramm, D.; Ariffin, A. K.

2018-05-01

Modeling a cable model in multibody dynamics simulation tool which dynamically varies in length, mass and stiffness is a challenging task. Simulation of cable-driven parallel robots (CDPR) for instance requires a cable model that can dynamically change in length for every desired pose of the platform. Thus, in this paper, a detailed procedure for modeling and simulation of a dynamic cable model in Dymola is proposed. The approach is also applicable for other types of Modelica simulation environments. The cable is modeled using standard mechanical elements like mass, spring, damper and joint. The parameters of the cable model are based on the factsheet of the manufacturer and experimental results. Its dynamic ability is tested by applying it on a complete planar CDPR model in which the parameters are based on a prototype named CABLAR, which is developed in Chair of Mechatronics, University of Duisburg-Essen. The prototype has been developed to demonstrate an application of CDPR as a goods storage and retrieval machine. The performance of the cable model during the simulation is analyzed and discussed.

Multiscale simulations of patchy particle systems combining Molecular Dynamics, Path Sampling and Green's Function Reaction Dynamics

NASA Astrophysics Data System (ADS)

Bolhuis, Peter

Important reaction-diffusion processes, such as biochemical networks in living cells, or self-assembling soft matter, span many orders in length and time scales. In these systems, the reactants' spatial dynamics at mesoscopic length and time scales of microns and seconds is coupled to the reactions between the molecules at microscopic length and time scales of nanometers and milliseconds. This wide range of length and time scales makes these systems notoriously difficult to simulate. While mean-field rate equations cannot describe such processes, the mesoscopic Green's Function Reaction Dynamics (GFRD) method enables efficient simulation at the particle level provided the microscopic dynamics can be integrated out. Yet, many processes exhibit non-trivial microscopic dynamics that can qualitatively change the macroscopic behavior, calling for an atomistic, microscopic description. The recently developed multiscale Molecular Dynamics Green's Function Reaction Dynamics (MD-GFRD) approach combines GFRD for simulating the system at the mesocopic scale where particles are far apart, with microscopic Molecular (or Brownian) Dynamics, for simulating the system at the microscopic scale where reactants are in close proximity. The association and dissociation of particles are treated with rare event path sampling techniques. I will illustrate the efficiency of this method for patchy particle systems. Replacing the microscopic regime with a Markov State Model avoids the microscopic regime completely. The MSM is then pre-computed using advanced path-sampling techniques such as multistate transition interface sampling. I illustrate this approach on patchy particle systems that show multiple modes of binding. MD-GFRD is generic, and can be used to efficiently simulate reaction-diffusion systems at the particle level, including the orientational dynamics, opening up the possibility for large-scale simulations of e.g. protein signaling networks.

Real-time dynamics simulation of the Cassini spacecraft using DARTS. Part 1: Functional capabilities and the spatial algebra algorithm

NASA Technical Reports Server (NTRS)

Jain, A.; Man, G. K.

1993-01-01

This paper describes the Dynamics Algorithms for Real-Time Simulation (DARTS) real-time hardware-in-the-loop dynamics simulator for the National Aeronautics and Space Administration's Cassini spacecraft. The spacecraft model consists of a central flexible body with a number of articulated rigid-body appendages. The demanding performance requirements from the spacecraft control system require the use of a high fidelity simulator for control system design and testing. The DARTS algorithm provides a new algorithmic and hardware approach to the solution of this hardware-in-the-loop simulation problem. It is based upon the efficient spatial algebra dynamics for flexible multibody systems. A parallel and vectorized version of this algorithm is implemented on a low-cost, multiprocessor computer to meet the simulation timing requirements.

An AD100 implementation of a real-time STOVL aircraft propulsion system

NASA Technical Reports Server (NTRS)

Ouzts, Peter J.; Drummond, Colin K.

1990-01-01

A real-time dynamic model of the propulsion system for a Short Take-Off and Vertical Landing (STOVL) aircraft was developed for the AD100 simulation environment. The dynamic model was adapted from a FORTRAN based simulation using the dynamic programming capabilities of the AD100 ADSIM simulation language. The dynamic model includes an aerothermal representation of a turbofan jet engine, actuator and sensor models, and a multivariable control system. The AD100 model was tested for agreement with the FORTRAN model and real-time execution performance. The propulsion system model was also linked to an airframe dynamic model to provide an overall STOVL aircraft simulation for the purposes of integrated flight and propulsion control studies. An evaluation of the AD100 system for use as an aircraft simulation environment is included.

CADLIVE toolbox for MATLAB: automatic dynamic modeling of biochemical networks with comprehensive system analysis.

PubMed

Inoue, Kentaro; Maeda, Kazuhiro; Miyabe, Takaaki; Matsuoka, Yu; Kurata, Hiroyuki

2014-09-01

Mathematical modeling has become a standard technique to understand the dynamics of complex biochemical systems. To promote the modeling, we had developed the CADLIVE dynamic simulator that automatically converted a biochemical map into its associated mathematical model, simulated its dynamic behaviors and analyzed its robustness. To enhance the feasibility by CADLIVE and extend its functions, we propose the CADLIVE toolbox available for MATLAB, which implements not only the existing functions of the CADLIVE dynamic simulator, but also the latest tools including global parameter search methods with robustness analysis. The seamless, bottom-up processes consisting of biochemical network construction, automatic construction of its dynamic model, simulation, optimization, and S-system analysis greatly facilitate dynamic modeling, contributing to the research of systems biology and synthetic biology. This application can be freely downloaded from http://www.cadlive.jp/CADLIVE_MATLAB/ together with an instruction.

Software-Engineering Process Simulation (SEPS) model

NASA Technical Reports Server (NTRS)

Lin, C. Y.; Abdel-Hamid, T.; Sherif, J. S.

1992-01-01

The Software Engineering Process Simulation (SEPS) model is described which was developed at JPL. SEPS is a dynamic simulation model of the software project development process. It uses the feedback principles of system dynamics to simulate the dynamic interactions among various software life cycle development activities and management decision making processes. The model is designed to be a planning tool to examine tradeoffs of cost, schedule, and functionality, and to test the implications of different managerial policies on a project's outcome. Furthermore, SEPS will enable software managers to gain a better understanding of the dynamics of software project development and perform postmodern assessments.

Molecular dynamics simulations of collision-induced absorption: Implementation in LAMMPS

NASA Astrophysics Data System (ADS)

Fakhardji, W.; Gustafsson, M.

2017-02-01

We pursue simulations of collision-induced absorption in a mixture of argon and xenon gas at room temperature by means of classical molecular dynamics. The established theoretical approach (Hartmann et al. 2011 J. Chem. Phys. 134 094316) is implemented with the molecular dynamics package LAMMPS. The bound state features in the absorption spectrum are well reproduced with the molecular dynamics simulation in comparison with a laboratory measurement. The magnitude of the computed absorption, however, is underestimated in a large part of the spectrum. We suggest some aspects of the simulation that could be improved.

Simulating Food Web Dynamics along a Gradient: Quantifying Human Influence

PubMed Central

Jordán, Ferenc; Gjata, Nerta; Mei, Shu; Yule, Catherine M.

2012-01-01

Realistically parameterized and dynamically simulated food-webs are useful tool to explore the importance of the functional diversity of ecosystems, and in particular relations between the dynamics of species and the whole community. We present a stochastic dynamical food web simulation for the Kelian River (Borneo). The food web was constructed for six different locations, arrayed along a gradient of increasing human perturbation (mostly resulting from gold mining activities) along the river. Along the river, the relative importance of grazers, filterers and shredders decreases with increasing disturbance downstream, while predators become more dominant in governing eco-dynamics. Human activity led to increased turbidity and sedimentation which adversely impacts primary productivity. Since the main difference between the study sites was not the composition of the food webs (structure is quite similar) but the strengths of interactions and the abundance of the trophic groups, a dynamical simulation approach seemed to be useful to better explain human influence. In the pristine river (study site 1), when comparing a structural version of our model with the dynamical model we found that structurally central groups such as omnivores and carnivores were not the most important ones dynamically. Instead, primary consumers such as invertebrate grazers and shredders generated a greater dynamical response. Based on the dynamically most important groups, bottom-up control is replaced by the predominant top-down control regime as distance downstream and human disturbance increased. An important finding, potentially explaining the poor structure to dynamics relationship, is that indirect effects are at least as important as direct ones during the simulations. We suggest that our approach and this simulation framework could serve systems-based conservation efforts. Quantitative indicators on the relative importance of trophic groups and the mechanistic modeling of eco-dynamics could greatly contribute to understanding various aspects of functional diversity. PMID:22768346

System Simulation by Recursive Feedback: Coupling a Set of Stand-Alone Subsystem Simulations

NASA Technical Reports Server (NTRS)

Nixon, D. D.

2001-01-01

Conventional construction of digital dynamic system simulations often involves collecting differential equations that model each subsystem, arran g them to a standard form, and obtaining their numerical gin solution as a single coupled, total-system simultaneous set. Simulation by numerical coupling of independent stand-alone subsimulations is a fundamentally different approach that is attractive because, among other things, the architecture naturally facilitates high fidelity, broad scope, and discipline independence. Recursive feedback is defined and discussed as a candidate approach to multidiscipline dynamic system simulation by numerical coupling of self-contained, single-discipline subsystem simulations. A satellite motion example containing three subsystems (orbit dynamics, attitude dynamics, and aerodynamics) has been defined and constructed using this approach. Conventional solution methods are used in the subsystem simulations. Distributed and centralized implementations of coupling have been considered. Numerical results are evaluated by direct comparison with a standard total-system, simultaneous-solution approach.

Simulating the flow of entangled polymers.

PubMed

Masubuchi, Yuichi

2014-01-01

To optimize automation for polymer processing, attempts have been made to simulate the flow of entangled polymers. In industry, fluid dynamics simulations with phenomenological constitutive equations have been practically established. However, to account for molecular characteristics, a method to obtain the constitutive relationship from the molecular structure is required. Molecular dynamics simulations with atomic description are not practical for this purpose; accordingly, coarse-grained models with reduced degrees of freedom have been developed. Although the modeling of entanglement is still a challenge, mesoscopic models with a priori settings to reproduce entangled polymer dynamics, such as tube models, have achieved remarkable success. To use the mesoscopic models as staging posts between atomistic and fluid dynamics simulations, studies have been undertaken to establish links from the coarse-grained model to the atomistic and macroscopic simulations. Consequently, integrated simulations from materials chemistry to predict the macroscopic flow in polymer processing are forthcoming.

Motions and entropies in proteins as seen in NMR relaxation experiments and molecular dynamics simulations.

PubMed

Allnér, Olof; Foloppe, Nicolas; Nilsson, Lennart

2015-01-22

Molecular dynamics simulations of E. coli glutaredoxin1 in water have been performed to relate the dynamical parameters and entropy obtained in NMR relaxation experiments, with results extracted from simulated trajectory data. NMR relaxation is the most widely used experimental method to obtain data on dynamics of proteins, but it is limited to relatively short timescales and to motions of backbone amides or in some cases (13)C-H vectors. By relating the experimental data to the all-atom picture obtained in molecular dynamics simulations, valuable insights on the interpretation of the experiment can be gained. We have estimated the internal dynamics and their timescales by calculating the generalized order parameters (O) for different time windows. We then calculate the quasiharmonic entropy (S) and compare it to the entropy calculated from the NMR-derived generalized order parameter of the amide vectors. Special emphasis is put on characterizing dynamics that are not expressed through the motions of the amide group. The NMR and MD methods suffer from complementary limitations, with NMR being restricted to local vectors and dynamics on a timescale determined by the rotational diffusion of the solute, while in simulations, it may be difficult to obtain sufficient sampling to ensure convergence of the results. We also evaluate the amount of sampling obtained with molecular dynamics simulations and how it is affected by the length of individual simulations, by clustering of the sampled conformations. We find that two structural turns act as hinges, allowing the α helix between them to undergo large, long timescale motions that cannot be detected in the time window of the NMR dipolar relaxation experiments. We also show that the entropy obtained from the amide vector does not account for correlated motions of adjacent residues. Finally, we show that the sampling in a total of 100 ns molecular dynamics simulation can be increased by around 50%, by dividing the trajectory into 10 replicas with different starting velocities.

Dielectric Properties of Poly(ethylene oxide) from Molecular Dynamics Simulations

NASA Technical Reports Server (NTRS)

Smith, Grant D.

1994-01-01

The order, conformations and dynamics of poly(oxyethylene) (POE) melts have been investigated through molecular dynamics simulations. The potential energy functions were determined from detailed ab initio electronic structure calculations of the conformational energies of the model molecules 1,2-dimethoxyethane (DME) and diethylether. The x-ray structure factor for POE from simulation will be compared to experiment. In terms of conformation, simulations reveal that chains are extended in the melt relative to isolated chains due to the presence of strong intermolecular O...H interactions, which occur at the expense of intramolecular O...H interactions. Conformational dynamics about the C-C bond were found to be significantly faster than in polymethylene, while conformational dynamics about the C-O bond even faster than the C-C dynamics. The faster local dynamics in POE relative to polymethylene is consistent with C-13 NMR spin-lattice relaxation experiments. Conformational transitions showed significant second-neighbor correlation, as was found for polymethylene. This correlation of transitions with C-C neighbors was found to be reduced relative to C-O neighbors. Dielectric relaxation from simulation will also be compared with experiment.

Similarities between principal components of protein dynamics and random diffusion

NASA Astrophysics Data System (ADS)

Hess, Berk

2000-12-01

Principal component analysis, also called essential dynamics, is a powerful tool for finding global, correlated motions in atomic simulations of macromolecules. It has become an established technique for analyzing molecular dynamics simulations of proteins. The first few principal components of simulations of large proteins often resemble cosines. We derive the principal components for high-dimensional random diffusion, which are almost perfect cosines. This resemblance between protein simulations and noise implies that for many proteins the time scales of current simulations are too short to obtain convergence of collective motions.

Development of a Dynamically Configurable, Object-Oriented Framework for Distributed, Multi-modal Computational Aerospace Systems Simulation

NASA Technical Reports Server (NTRS)

Afjeh, Abdollah A.; Reed, John A.

2003-01-01

The following reports are presented on this project:A first year progress report on: Development of a Dynamically Configurable,Object-Oriented Framework for Distributed, Multi-modal Computational Aerospace Systems Simulation; A second year progress report on: Development of a Dynamically Configurable, Object-Oriented Framework for Distributed, Multi-modal Computational Aerospace Systems Simulation; An Extensible, Interchangeable and Sharable Database Model for Improving Multidisciplinary Aircraft Design; Interactive, Secure Web-enabled Aircraft Engine Simulation Using XML Databinding Integration; and Improving the Aircraft Design Process Using Web-based Modeling and Simulation.

Dynamics of Protonated Peptide Ion Collisions with Organic Surfaces: Consonance of Simulation and Experiment

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

Pratihar, Subha; Barnes, George L.; Laskin, Julia

In this Perspective mass spectrometry experiments and chemical dynamics simulations are described which have explored the atomistic dynamics of protonated peptide ions, peptide-H+, colliding with organic surfaces. These studies have investigated surface-induced dissociation (SID) for which peptide-H+ fragments upon collision with the surface, peptide-H+ physisorption on the surface, soft landing (SL), and peptide-H+ reaction with the surface, reactive landing (RL). The simulations include QM+MM and QM/MM direct dynamics. For collisions with self-assembled monolayer (SAM) surfaces there is quite good agreement between experiment and simulation in the efficiency of energy transfer to the peptide-H+ ion’s internal degrees of freedom. Both themore » experiments and simulations show two mechanisms for peptide-H+ fragmentation, i.e. shattering and statistical, RRKM dynamics. Mechanisms for SL are probed in simulations of collisions of protonated dialanine with a perfluorinated SAM surface. RL has been studied experimentally for a number of peptide-H+ + surface systems, and qualitative agreement between simulation and experiment is found for two similar systems.« less

Dynamic computer simulations of electrophoresis: three decades of active research.

PubMed

Thormann, Wolfgang; Caslavska, Jitka; Breadmore, Michael C; Mosher, Richard A

2009-06-01

Dynamic models for electrophoresis are based upon model equations derived from the transport concepts in solution together with user-inputted conditions. They are able to predict theoretically the movement of ions and are as such the most versatile tool to explore the fundamentals of electrokinetic separations. Since its inception three decades ago, the state of dynamic computer simulation software and its use has progressed significantly and Electrophoresis played a pivotal role in that endeavor as a large proportion of the fundamental and application papers were published in this periodical. Software is available that simulates all basic electrophoretic systems, including moving boundary electrophoresis, zone electrophoresis, ITP, IEF and EKC, and their combinations under almost exactly the same conditions used in the laboratory. This has been employed to show the detailed mechanisms of many of the fundamental phenomena that occur in electrophoretic separations. Dynamic electrophoretic simulations are relevant for separations on any scale and instrumental format, including free-fluid preparative, gel, capillary and chip electrophoresis. This review includes a historical overview, a survey of current simulators, simulation examples and a discussion of the applications and achievements of dynamic simulation.

Next Generation Extended Lagrangian Quantum-based Molecular Dynamics

NASA Astrophysics Data System (ADS)

Negre, Christian

2017-06-01

A new framework for extended Lagrangian first-principles molecular dynamics simulations is presented, which overcomes shortcomings of regular, direct Born-Oppenheimer molecular dynamics, while maintaining important advantages of the unified extended Lagrangian formulation of density functional theory pioneered by Car and Parrinello three decades ago. The new framework allows, for the first time, energy conserving, linear-scaling Born-Oppenheimer molecular dynamics simulations, which is necessary to study larger and more realistic systems over longer simulation times than previously possible. Expensive, self-consinstent-field optimizations are avoided and normal integration time steps of regular, direct Born-Oppenheimer molecular dynamics can be used. Linear scaling electronic structure theory is presented using a graph-based approach that is ideal for parallel calculations on hybrid computer platforms. For the first time, quantum based Born-Oppenheimer molecular dynamics simulation is becoming a practically feasible approach in simulations of +100,000 atoms-representing a competitive alternative to classical polarizable force field methods. In collaboration with: Anders Niklasson, Los Alamos National Laboratory.

Equivalence of Brownian dynamics and dynamic Monte Carlo simulations in multicomponent colloidal suspensions.

PubMed

Cuetos, Alejandro; Patti, Alessandro

2015-08-01

We propose a simple but powerful theoretical framework to quantitatively compare Brownian dynamics (BD) and dynamic Monte Carlo (DMC) simulations of multicomponent colloidal suspensions. By extending our previous study focusing on monodisperse systems of rodlike colloids, here we generalize the formalism described there to multicomponent colloidal mixtures and validate it by investigating the dynamics in isotropic and liquid crystalline phases containing spherical and rodlike particles. In order to investigate the dynamics of multicomponent colloidal systems by DMC simulations, it is key to determine the elementary time step of each species and establish a unique timescale. This is crucial to consistently study the dynamics of colloidal particles with different geometry. By analyzing the mean-square displacement, the orientation autocorrelation functions, and the self part of the van Hove correlation functions, we show that DMC simulation is a very convenient and reliable technique to describe the stochastic dynamics of any multicomponent colloidal system. Our theoretical formalism can be easily extended to any colloidal system containing size and/or shape polydisperse particles.

Flight Dynamic Simulation of Fighter In the Asymmetric External Store Release Process

NASA Astrophysics Data System (ADS)

Safi’i, Imam; Arifianto, Ony; Nurohman, Chandra

2018-04-01

In the fighter design, it is important to evaluate and analyze the flight dynamic of the aircraft earlier in the development process. One of the case is the dynamics of external store release process. A simulation tool can be used to analyze the fighter/external store system’s dynamics in the preliminary design stage. This paper reports the flight dynamics of Jet Fighter Experiment (JF-1 E) in asymmetric Advance Medium Range Air to Air Missile (AMRAAM) release process through simulations. The JF-1 E and AIM 120 AMRAAAM models are built by using Advanced Aircraft Analysis (AAA) and Missile Datcom software. By using these softwares, the aerodynamic stability and control derivatives can be obtained and used to model the dynamic characteristic of the fighter and the external store. The dynamic system is modeled by using MATLAB/Simulink software. By using this software, both the fighter/external store integration and the external store release process is simulated, and the dynamic of the system can be analyzed.

Molecular dynamics simulations of a K+ channel blocker: Tc1 toxin from Tityus cambridgei.

PubMed

Grottesi, Alessandro; Sansom, Mark S P

2003-01-30

Toxins that block voltage-gated potassium (Kv) channels provide a possible template for improved homology models of the Kv pore. In assessing the interactions of Kv channels and their toxins it is important to determine the dynamic flexibility of the toxins. Multiple 10 ns duration molecular dynamics simulations combined with essential dynamics analysis have been used to explore the flexibility of four different Kv channel-blocking toxins. Three toxins (Tc1, AgTx and ChTx) share a common fold. They also share a common pattern of conformational dynamics, as revealed by essential dynamics analysis of the simulation results. This suggests that some aspects of dynamic behaviour are conserved across a single protein fold class. In each of these three toxins, the residue exhibiting minimum flexibility corresponds to a conserved lysine residue that is suggested to interact with the filter domain of the channel. Thus, comparative simulations reveal functionally important conservation of molecular dynamics as well as protein fold across a family of related toxins.

Application of control theory to dynamic systems simulation

NASA Technical Reports Server (NTRS)

Auslander, D. M.; Spear, R. C.; Young, G. E.

1982-01-01

The application of control theory is applied to dynamic systems simulation. Theory and methodology applicable to controlled ecological life support systems are considered. Spatial effects on system stability, design of control systems with uncertain parameters, and an interactive computing language (PARASOL-II) designed for dynamic system simulation, report quality graphics, data acquisition, and simple real time control are discussed.

Rob Guglielmetti | NREL

Science.gov Websites

2009. Rob's areas of expertise are daylighting, physically based lighting simulation, the integration of lighting simulation with whole-building energy simulations, and high-dynamic range imaging. He has simulation, and high-dynamic range imaging. Rob is an advisory member of the Illuminating Engineering Society

Characterizing rare-event property distributions via replicate molecular dynamics simulations of proteins.

PubMed

Krishnan, Ranjani; Walton, Emily B; Van Vliet, Krystyn J

2009-11-01

As computational resources increase, molecular dynamics simulations of biomolecules are becoming an increasingly informative complement to experimental studies. In particular, it has now become feasible to use multiple initial molecular configurations to generate an ensemble of replicate production-run simulations that allows for more complete characterization of rare events such as ligand-receptor unbinding. However, there are currently no explicit guidelines for selecting an ensemble of initial configurations for replicate simulations. Here, we use clustering analysis and steered molecular dynamics simulations to demonstrate that the configurational changes accessible in molecular dynamics simulations of biomolecules do not necessarily correlate with observed rare-event properties. This informs selection of a representative set of initial configurations. We also employ statistical analysis to identify the minimum number of replicate simulations required to sufficiently sample a given biomolecular property distribution. Together, these results suggest a general procedure for generating an ensemble of replicate simulations that will maximize accurate characterization of rare-event property distributions in biomolecules.

Structure and dynamics of complex liquid water: Molecular dynamics simulation

NASA Astrophysics Data System (ADS)

S, Indrajith V.; Natesan, Baskaran

2015-06-01

We have carried out detailed structure and dynamical studies of complex liquid water using molecular dynamics simulations. Three different model potentials, namely, TIP3P, TIP4P and SPC-E have been used in the simulations, in order to arrive at the best possible potential function that could reproduce the structure of experimental bulk water. All the simulations were performed in the NVE micro canonical ensemble using LAMMPS. The radial distribution functions, gOO, gOH and gHH and the self diffusion coefficient, Ds, were calculated for all three models. We conclude from our results that the structure and dynamical parameters obtained for SPC-E model matched well with the experimental values, suggesting that among the models studied here, the SPC-E model gives the best structure and dynamics of bulk water.

The influence of fatty acids on the GpA dimer interface by coarse-grained molecular dynamics simulation.

PubMed

Flinner, Nadine; Mirus, Oliver; Schleiff, Enrico

2014-08-15

The hydrophobic thickness of membranes, which is manly defined by fatty acids, influences the packing of transmembrane domains of proteins and thus can modulate the activity of these proteins. We analyzed the dynamics of the dimerization of Glycophorin A (GpA) by molecular dynamics simulations to describe the fatty acid dependence of the transmembrane region assembly. GpA represents a well-established model for dimerization of single transmembrane helices containing a GxxxG motif in vitro and in silico. We performed simulations of the dynamics of the NMR-derived dimer as well as self-assembly simulations of monomers in membranes composed of different fatty acid chains and monitored the formed interfaces and their transitions. The observed dimeric interfaces, which also include the one known from NMR, are highly dynamic and converted into each other. The frequency of interface formation and the preferred transitions between interfaces similar to the interface observed by NMR analysis strongly depend on the fatty acid used to build the membrane. Molecular dynamic simulations after adaptation of the helix topology parameters to better represent NMR derived structures of single transmembrane helices yielded an enhanced occurrence of the interface determined by NMR in molecular dynamics simulations. Taken together we give insights into the influence of fatty acids and helix conformation on the dynamics of the transmembrane domain of GpA.

The Influence of Fatty Acids on the GpA Dimer Interface by Coarse-Grained Molecular Dynamics Simulation

PubMed Central

Flinner, Nadine; Mirus, Oliver; Schleiff, Enrico

2014-01-01

The hydrophobic thickness of membranes, which is manly defined by fatty acids, influences the packing of transmembrane domains of proteins and thus can modulate the activity of these proteins. We analyzed the dynamics of the dimerization of Glycophorin A (GpA) by molecular dynamics simulations to describe the fatty acid dependence of the transmembrane region assembly. GpA represents a well-established model for dimerization of single transmembrane helices containing a GxxxG motif in vitro and in silico. We performed simulations of the dynamics of the NMR-derived dimer as well as self-assembly simulations of monomers in membranes composed of different fatty acid chains and monitored the formed interfaces and their transitions. The observed dimeric interfaces, which also include the one known from NMR, are highly dynamic and converted into each other. The frequency of interface formation and the preferred transitions between interfaces similar to the interface observed by NMR analysis strongly depend on the fatty acid used to build the membrane. Molecular dynamic simulations after adaptation of the helix topology parameters to better represent NMR derived structures of single transmembrane helices yielded an enhanced occurrence of the interface determined by NMR in molecular dynamics simulations. Taken together we give insights into the influence of fatty acids and helix conformation on the dynamics of the transmembrane domain of GpA. PMID:25196522

Dynamic performance of accommodating intraocular lenses in a negative feedback control system: a simulation-based study.

PubMed

Schor, Clifton M; Bharadwaj, Shrikant R; Burns, Christopher D

2007-07-01

A dynamic model of ocular accommodation is used to simulate the stability and dynamic performance of accommodating intraocular lenses (A-IOLs) that replace the hardened natural ocular lens that is unable to change focus. Accommodation simulations of an older eye with A-IOL materials having biomechanical properties of a younger eye illustrate overshoots and oscillations resulting from decreased visco-elasticity of the A-IOL. Stable dynamics of an A-IOL are restored by adaptation of phasic and tonic neural-control properties of accommodation. Simulations indicate that neural control must be recalibrated to avoid unstable dynamic accommodation with A-IOLs. An interactive web-model of A-IOL illustrating these properties is available at http://schorlab.berkeley.edu.

Molecular dynamics simulations of membrane proteins and their interactions: from nanoscale to mesoscale.

PubMed

Chavent, Matthieu; Duncan, Anna L; Sansom, Mark Sp

2016-10-01

Molecular dynamics simulations provide a computational tool to probe membrane proteins and systems at length scales ranging from nanometers to close to a micrometer, and on microsecond timescales. All atom and coarse-grained simulations may be used to explore in detail the interactions of membrane proteins and specific lipids, yielding predictions of lipid binding sites in good agreement with available structural data. Building on the success of protein-lipid interaction simulations, larger scale simulations reveal crowding and clustering of proteins, resulting in slow and anomalous diffusional dynamics, within realistic models of cell membranes. Current methods allow near atomic resolution simulations of small membrane organelles, and of enveloped viruses to be performed, revealing key aspects of their structure and functionally important dynamics. Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Molecular Dynamics Simulations of Shear Induced Transformations in Nitromethane

NASA Astrophysics Data System (ADS)

Larentzos, James; Steele, Brad

2017-06-01

Recent experiments demonstrate that NM undergoes explosive chemical initiation under compressive shear stress. The atomistic dynamics of the shear response of single-crystalline and bi-crystalline nitromethane (NM) are simulated using molecular dynamics simulations under high pressure conditions to aid in interpreting these experiments. The atomic interactions are described using a recently re-optimized ReaxFF-lg potential trained specifically for NM under pressure. The simulations demonstrate that the NM crystal transforms into a disordered state upon sufficient application of shear stress; its maximum value, shear angle, and atomic-scale dynamics being highly dependent on crystallographic orientation of the applied shear. Shear simulations in bi-crystalline NM show more complex behavior resulting in the appearance of the disordered state at the grain boundary.

Molecular Dynamics Simulations of Shear Induced Transformations in Nitromethane

NASA Astrophysics Data System (ADS)

Larentzos, James; Steele, Brad

Recent experiments demonstrate that NM undergoes explosive chemical initiation under compressive shear stress. The atomistic dynamics of the shear response of single-crystalline and bi-crystalline nitromethane (NM) are simulated using molecular dynamics simulations under high pressure conditions to aid in interpreting these experiments. The atomic interactions are described using a recently re-optimized ReaxFF-lg potential trained specifically for NM under pressure. The simulations demonstrate that the NM crystal transforms into a disordered state upon sufficient application of shear stress; its maximum value, shear angle, and atomic-scale dynamics being highly dependent on crystallographic orientation of the applied shear. Shear simulations in bi-crystalline NM show more complex behavior resulting in the appearance of the disordered state at the grain boundary.

Near real-time traffic routing

NASA Technical Reports Server (NTRS)

Yang, Chaowei (Inventor); Xie, Jibo (Inventor); Zhou, Bin (Inventor); Cao, Ying (Inventor)

2012-01-01

A near real-time physical transportation network routing system comprising: a traffic simulation computing grid and a dynamic traffic routing service computing grid. The traffic simulator produces traffic network travel time predictions for a physical transportation network using a traffic simulation model and common input data. The physical transportation network is divided into a multiple sections. Each section has a primary zone and a buffer zone. The traffic simulation computing grid includes multiple of traffic simulation computing nodes. The common input data includes static network characteristics, an origin-destination data table, dynamic traffic information data and historical traffic data. The dynamic traffic routing service computing grid includes multiple dynamic traffic routing computing nodes and generates traffic route(s) using the traffic network travel time predictions.

Compression Behavior and Energy Absorption of Aluminum Alloy AA6061 Tubes with Multiple Holes

NASA Astrophysics Data System (ADS)

Simhachalam, Bade; Lakshmana Rao, C.; Srinivas, Krishna

2014-05-01

In this article, compression behavior and energy absorption of aluminum alloy AA6061 tubes are investigated both experimentally and numerically. Static and dynamic simulations are done using LS-Dyna Software for AA6061 tubes. True stress-plastic strain curves from the tensile test are used in the static and dynamic simulations of AA6061 tubes. The energy absorption values between experimental compression results and numeral simulation are found to be in good agreement. Dynamic simulations are done with drop velocity of up to 10 m/s to understand the inertia effects on energy absorption. The deformed modes from the numerical simulation are compared between tubes with and without holes in static and dynamic conditions.

Code Samples Used for Complexity and Control

NASA Astrophysics Data System (ADS)

Ivancevic, Vladimir G.; Reid, Darryn J.

2015-11-01

The following sections are included: * MathematicaⓇ Code * Generic Chaotic Simulator * Vector Differential Operators * NLS Explorer * 2C++ Code * C++ Lambda Functions for Real Calculus * Accelerometer Data Processor * Simple Predictor-Corrector Integrator * Solving the BVP with the Shooting Method * Linear Hyperbolic PDE Solver * Linear Elliptic PDE Solver * Method of Lines for a Set of the NLS Equations * C# Code * Iterative Equation Solver * Simulated Annealing: A Function Minimum * Simple Nonlinear Dynamics * Nonlinear Pendulum Simulator * Lagrangian Dynamics Simulator * Complex-Valued Crowd Attractor Dynamics * Freeform Fortran Code * Lorenz Attractor Simulator * Complex Lorenz Attractor * Simple SGE Soliton * Complex Signal Presentation * Gaussian Wave Packet * Hermitian Matrices * Euclidean L2-Norm * Vector/Matrix Operations * Plain C-Code: Levenberg-Marquardt Optimizer * Free Basic Code: 2D Crowd Dynamics with 3000 Agents

Liquid li structure and dynamics: A comparison between OFDFT and second nearest-neighbor embedded-atom method

DOE PAGES

Chen, Mohan; Vella, Joseph R.; Panagiotopoulos, Athanassios Z.; ...

2015-04-08

The structure and dynamics of liquid lithium are studied using two simulation methods: orbital-free (OF) first-principles molecular dynamics (MD), which employs OF density functional theory (DFT), and classical MD utilizing a second nearest-neighbor embedded-atom method potential. The properties we studied include the dynamic structure factor, the self-diffusion coefficient, the dispersion relation, the viscosity, and the bond angle distribution function. Our simulation results were compared to available experimental data when possible. Each method has distinct advantages and disadvantages. For example, OFDFT gives better agreement with experimental dynamic structure factors, yet is more computationally demanding than classical simulations. Classical simulations can accessmore » a broader temperature range and longer time scales. The combination of first-principles and classical simulations is a powerful tool for studying properties of liquid lithium.« less

Advanced Simulation of Coupled Earthquake and Tsunami Events

NASA Astrophysics Data System (ADS)

Behrens, Joern

2013-04-01

Tsunami-Earthquakes represent natural catastrophes threatening lives and well-being of societies in a solitary and unexpected extreme event as tragically demonstrated in Sumatra (2004), Samoa (2009), Chile (2010), or Japan (2011). Both phenomena are consequences of the complex system of interactions of tectonic stress, fracture mechanics, rock friction, rupture dynamics, fault geometry, ocean bathymetry, and coastline geometry. The ASCETE project forms an interdisciplinary research consortium that couples the most advanced simulation technologies for earthquake rupture dynamics and tsunami propagation to understand the fundamental conditions of tsunami generation. We report on the latest research results in physics-based dynamic rupture and tsunami wave propagation simulation, using unstructured and adaptive meshes with continuous and discontinuous Galerkin discretization approaches. Coupling both simulation tools - the physics-based dynamic rupture simulation and the hydrodynamic tsunami wave propagation - will give us the possibility to conduct highly realistic studies of the interaction of rupture dynamics and tsunami impact characteristics.

Accelerated molecular dynamics: A promising and efficient simulation method for biomolecules

NASA Astrophysics Data System (ADS)

Hamelberg, Donald; Mongan, John; McCammon, J. Andrew

2004-06-01

Many interesting dynamic properties of biological molecules cannot be simulated directly using molecular dynamics because of nanosecond time scale limitations. These systems are trapped in potential energy minima with high free energy barriers for large numbers of computational steps. The dynamic evolution of many molecular systems occurs through a series of rare events as the system moves from one potential energy basin to another. Therefore, we have proposed a robust bias potential function that can be used in an efficient accelerated molecular dynamics approach to simulate the transition of high energy barriers without any advance knowledge of the location of either the potential energy wells or saddle points. In this method, the potential energy landscape is altered by adding a bias potential to the true potential such that the escape rates from potential wells are enhanced, which accelerates and extends the time scale in molecular dynamics simulations. Our definition of the bias potential echoes the underlying shape of the potential energy landscape on the modified surface, thus allowing for the potential energy minima to be well defined, and hence properly sampled during the simulation. We have shown that our approach, which can be extended to biomolecules, samples the conformational space more efficiently than normal molecular dynamics simulations, and converges to the correct canonical distribution.

Integrating atomistic molecular dynamics simulations, experiments, and network analysis to study protein dynamics: strength in unity.

PubMed

Papaleo, Elena

2015-01-01

In the last years, we have been observing remarkable improvements in the field of protein dynamics. Indeed, we can now study protein dynamics in atomistic details over several timescales with a rich portfolio of experimental and computational techniques. On one side, this provides us with the possibility to validate simulation methods and physical models against a broad range of experimental observables. On the other side, it also allows a complementary and comprehensive view on protein structure and dynamics. What is needed now is a better understanding of the link between the dynamic properties that we observe and the functional properties of these important cellular machines. To make progresses in this direction, we need to improve the physical models used to describe proteins and solvent in molecular dynamics, as well as to strengthen the integration of experiments and simulations to overcome their own limitations. Moreover, now that we have the means to study protein dynamics in great details, we need new tools to understand the information embedded in the protein ensembles and in their dynamic signature. With this aim in mind, we should enrich the current tools for analysis of biomolecular simulations with attention to the effects that can be propagated over long distances and are often associated to important biological functions. In this context, approaches inspired by network analysis can make an important contribution to the analysis of molecular dynamics simulations.

Peptide crystal simulations reveal hidden dynamics

PubMed Central

Janowski, Pawel A.; Cerutti, David S.; Holton, James; Case, David A.

2013-01-01

Molecular dynamics simulations of biomolecular crystals at atomic resolution have the potential to recover information on dynamics and heterogeneity hidden in the X-ray diffraction data. We present here 9.6 microseconds of dynamics in a small helical peptide crystal with 36 independent copies of the unit cell. The average simulation structure agrees with experiment to within 0.28 Å backbone and 0.42 Å all-atom rmsd; a model refined against the average simulation density agrees with the experimental structure to within 0.20 Å backbone and 0.33 Å all-atom rmsd. The R-factor between the experimental structure factors and those derived from this unrestrained simulation is 23% to 1.0 Å resolution. The B-factors for most heavy atoms agree well with experiment (Pearson correlation of 0.90), but B-factors obtained by refinement against the average simulation density underestimate the coordinate fluctuations in the underlying simulation where the simulation samples alternate conformations. A dynamic flow of water molecules through channels within the crystal lattice is observed, yet the average water density is in remarkable agreement with experiment. A minor population of unit cells is characterized by reduced water content, 310 helical propensity and a gauche(−) side-chain rotamer for one of the valine residues. Careful examination of the experimental data suggests that transitions of the helices are a simulation artifact, although there is indeed evidence for alternate valine conformers and variable water content. This study highlights the potential for crystal simulations to detect dynamics and heterogeneity in experimental diffraction data, as well as to validate computational chemistry methods. PMID:23631449

Convergence and reproducibility in molecular dynamics simulations of the DNA duplex d(GCACGAACGAACGAACGC)

PubMed Central

Galindo-Murillo, Rodrigo; Roe, Daniel R.; Cheatham, Thomas E.

2014-01-01

Background The structure and dynamics of DNA are critically related to its function. Molecular dynamics (MD) simulations augment experiment by providing detailed information about the atomic motions. However, to date the simulations have not been long enough for convergence of the dynamics and structural properties of DNA. Methods MD simulations performed with AMBER using the ff99SB force field with the parmbsc0 modifications, including ensembles of independent simulations, were compared to long timescale MD performed with the specialized Anton MD engine on the B-DNA structure d(GCACGAACGAACGAACGC). To assess convergence, the decay of the average RMSD values over longer and longer time intervals was evaluated in addition to assessing convergence of the dynamics via the Kullback-Leibler divergence of principal component projection histograms. Results These MD simulations —including one of the longest simulations of DNA published to date at ~44 μs—surprisingly suggest that the structure and dynamics of the DNA helix, neglecting the terminal base pairs, are essentially fully converged on the ~1–5 μs timescale. Conclusions We can now reproducibly converge the structure and dynamics of B-DNA helices, omitting the terminal base pairs, on the μs time scale with both the AMBER and CHARMM C36 nucleic acid force fields. Results from independent ensembles of simulations starting from different initial conditions, when aggregated, match the results from long timescale simulations on the specialized Anton MD engine. General Significance With access to large-scale GPU resources or the specialized MD engine “Anton” it is possibly for a variety of molecular systems to reproducibly and reliably converge the conformational ensemble of sampled structures. PMID:25219455

A Quantitative Dynamic Simulation of Bremia lactucae Airborne Conidia Concentration above a Lettuce Canopy.

PubMed

Fall, Mamadou Lamine; Van der Heyden, Hervé; Carisse, Odile

2016-01-01

Lettuce downy mildew, caused by the oomycete Bremia lactucae Regel, is a major threat to lettuce production worldwide. Lettuce downy mildew is a polycyclic disease driven by airborne spores. A weather-based dynamic simulation model for B. lactucae airborne spores was developed to simulate the aerobiological characteristics of the pathogen. The model was built using the STELLA platform by following the system dynamics methodology. The model was developed using published equations describing disease subprocesses (e.g., sporulation) and assembled knowledge of the interactions among pathogen, host, and weather. The model was evaluated with four years of independent data by comparing model simulations with observations of hourly and daily airborne spore concentrations. The results show an accurate simulation of the trend and shape of B. lactucae temporal dynamics of airborne spore concentration. The model simulated hourly and daily peaks in airborne spore concentrations. More than 95% of the simulation runs, the daily-simulated airborne conidia concentration was 0 when airborne conidia were not observed. Also, the relationship between the simulated and the observed airborne spores was linear. In more than 94% of the simulation runs, the proportion of the linear variation in the hourly-observed values explained by the variation in the hourly-simulated values was greater than 0.7 in all years except one. Most of the errors came from the deviation from the 1:1 line, and the proportion of errors due to the model bias was low. This model is the only dynamic model developed to mimic the dynamics of airborne inoculum and represents an initial step towards improved lettuce downy mildew understanding, forecasting and management.

A Quantitative Dynamic Simulation of Bremia lactucae Airborne Conidia Concentration above a Lettuce Canopy

PubMed Central

Fall, Mamadou Lamine; Van der Heyden, Hervé; Carisse, Odile

2016-01-01

Lettuce downy mildew, caused by the oomycete Bremia lactucae Regel, is a major threat to lettuce production worldwide. Lettuce downy mildew is a polycyclic disease driven by airborne spores. A weather-based dynamic simulation model for B. lactucae airborne spores was developed to simulate the aerobiological characteristics of the pathogen. The model was built using the STELLA platform by following the system dynamics methodology. The model was developed using published equations describing disease subprocesses (e.g., sporulation) and assembled knowledge of the interactions among pathogen, host, and weather. The model was evaluated with four years of independent data by comparing model simulations with observations of hourly and daily airborne spore concentrations. The results show an accurate simulation of the trend and shape of B. lactucae temporal dynamics of airborne spore concentration. The model simulated hourly and daily peaks in airborne spore concentrations. More than 95% of the simulation runs, the daily-simulated airborne conidia concentration was 0 when airborne conidia were not observed. Also, the relationship between the simulated and the observed airborne spores was linear. In more than 94% of the simulation runs, the proportion of the linear variation in the hourly-observed values explained by the variation in the hourly-simulated values was greater than 0.7 in all years except one. Most of the errors came from the deviation from the 1:1 line, and the proportion of errors due to the model bias was low. This model is the only dynamic model developed to mimic the dynamics of airborne inoculum and represents an initial step towards improved lettuce downy mildew understanding, forecasting and management. PMID:26953691

SS-mPMG and SS-GA: tools for finding pathways and dynamic simulation of metabolic networks.

PubMed

Katsuragi, Tetsuo; Ono, Naoaki; Yasumoto, Keiichi; Altaf-Ul-Amin, Md; Hirai, Masami Y; Sriyudthsak, Kansuporn; Sawada, Yuji; Yamashita, Yui; Chiba, Yukako; Onouchi, Hitoshi; Fujiwara, Toru; Naito, Satoshi; Shiraishi, Fumihide; Kanaya, Shigehiko

2013-05-01

Metabolomics analysis tools can provide quantitative information on the concentration of metabolites in an organism. In this paper, we propose the minimum pathway model generator tool for simulating the dynamics of metabolite concentrations (SS-mPMG) and a tool for parameter estimation by genetic algorithm (SS-GA). SS-mPMG can extract a subsystem of the metabolic network from the genome-scale pathway maps to reduce the complexity of the simulation model and automatically construct a dynamic simulator to evaluate the experimentally observed behavior of metabolites. Using this tool, we show that stochastic simulation can reproduce experimentally observed dynamics of amino acid biosynthesis in Arabidopsis thaliana. In this simulation, SS-mPMG extracts the metabolic network subsystem from published databases. The parameters needed for the simulation are determined using a genetic algorithm to fit the simulation results to the experimental data. We expect that SS-mPMG and SS-GA will help researchers to create relevant metabolic networks and carry out simulations of metabolic reactions derived from metabolomics data.

Complex double-mass dynamic model of rotor on thrust foil gas dynamic bearings

NASA Astrophysics Data System (ADS)

Sytin, A.; Babin, A.; Vasin, S.

2017-08-01

The present paper considers simulation of a rotor’s dynamics behaviour on thrust foil gas dynamic bearings based on simultaneous solution of gas dynamics differential equations, equations of theory of elasticity, motion equations and some additional equations. A double-mass dynamic system was considered during the rotor’s motion simulation which allows not only evaluation of rotor’s dynamic behaviour, but also to evaluate the influence of operational and load parameters on the dynamics of the rotor-bearing system.

Experimental simulation of decoherence in photonics qudits

PubMed Central

Marques, B.; Matoso, A. A.; Pimenta, W. M.; Gutiérrez-Esparza, A. J.; Santos, M. F.; Pádua, S.

2015-01-01

We experimentally perform the simulation of open quantum dynamics in single-qudit systems. Using a spatial light modulator as a dissipative optical device, we implement dissipative-dynamical maps onto qudits encoded in the transverse momentum of spontaneous parametric down-converted photon pairs. We show a well-controlled technique to prepare entangled qudits states as well as to implement dissipative local measurements; the latter realize two specific dynamics: dephasing and amplitude damping. Our work represents a new analogy-dynamical experiment for simulating an open quantum system. PMID:26527330

Gamma ray observatory dynamics simulator in Ada (GRODY)

NASA Technical Reports Server (NTRS)

1990-01-01

This experiment involved the parallel development of dynamics simulators for the Gamma Ray Observatory in both FORTRAN and Ada for the purpose of evaluating the applicability of Ada to the NASA/Goddard Space Flight Center's flight dynamics environment. The experiment successfully demonstrated that Ada is a viable, valuable technology for use in this environment. In addition to building a simulator, the Ada team evaluated training approaches, developed an Ada methodology appropriate to the flight dynamics environment, and established a baseline for evaluating future Ada projects.

Brownian dynamics simulation of protein diffusion in crowded environments

NASA Astrophysics Data System (ADS)

Mereghetti, Paolo; Wade, Rebecca C.

2013-02-01

High macromolecular concentrations are a distinguishing feature of living organisms. Understanding how the high concentration of solutes affects the dynamic properties of biological macromolecules is fundamental for the comprehension of biological processes in living systems. We first describe the development of a Brownian dynamics simulation methodology to investigate the dynamic and structural properties of protein solutions using atomic-detail protein structures. We then discuss insights obtained from applying this approach to simulation of solutions of a range of types of proteins.

Digital Quantum Simulation of Z2 Lattice Gauge Theories with Dynamical Fermionic Matter

NASA Astrophysics Data System (ADS)

Zohar, Erez; Farace, Alessandro; Reznik, Benni; Cirac, J. Ignacio

2017-02-01

We propose a scheme for digital quantum simulation of lattice gauge theories with dynamical fermions. Using a layered optical lattice with ancilla atoms that can move and interact with the other atoms (simulating the physical degrees of freedom), we obtain a stroboscopic dynamics which yields the four-body plaquette interactions, arising in models with (2 +1 ) and higher dimensions, without the use of perturbation theory. As an example we show how to simulate a Z2 model in (2 +1 ) dimensions.

Robust state preparation in quantum simulations of Dirac dynamics

NASA Astrophysics Data System (ADS)

Song, Xue-Ke; Deng, Fu-Guo; Lamata, Lucas; Muga, J. G.

2017-02-01

A nonrelativistic system such as an ultracold trapped ion may perform a quantum simulation of a Dirac equation dynamics under specific conditions. The resulting Hamiltonian and dynamics are highly controllable, but the coupling between momentum and internal levels poses some difficulties to manipulate the internal states accurately in wave packets. We use invariants of motion to inverse engineer robust population inversion processes with a homogeneous, time-dependent simulated electric field. This exemplifies the usefulness of inverse-engineering techniques to improve the performance of quantum simulation protocols.

Dynamic Simulation of AN Helium Refrigerator

NASA Astrophysics Data System (ADS)

Deschildre, C.; Barraud, A.; Bonnay, P.; Briend, P.; Girard, A.; Poncet, J. M.; Roussel, P.; Sequeira, S. E.

2008-03-01

A dynamic simulation of a large scale existing refrigerator has been performed using the software Aspen Hysys®. The model comprises the typical equipments of a cryogenic system: heat exchangers, expanders, helium phase separators and cold compressors. It represents the 400 W @ 1.8 K Test Facility located at CEA—Grenoble. This paper describes the model development and shows the possibilities and limitations of the dynamic module of Aspen Hysys®. Then, comparison between simulation results and experimental data are presented; the simulation of cooldown process was also performed.

Digital Quantum Simulation of Z_{2} Lattice Gauge Theories with Dynamical Fermionic Matter.

PubMed

Zohar, Erez; Farace, Alessandro; Reznik, Benni; Cirac, J Ignacio

2017-02-17

We propose a scheme for digital quantum simulation of lattice gauge theories with dynamical fermions. Using a layered optical lattice with ancilla atoms that can move and interact with the other atoms (simulating the physical degrees of freedom), we obtain a stroboscopic dynamics which yields the four-body plaquette interactions, arising in models with (2+1) and higher dimensions, without the use of perturbation theory. As an example we show how to simulate a Z_{2} model in (2+1) dimensions.

A Low Cost Microcomputer System for Process Dynamics and Control Simulations.

ERIC Educational Resources Information Center

Crowl, D. A.; Durisin, M. J.

1983-01-01

Discusses a video simulator microcomputer system used to provide real-time demonstrations to strengthen students' understanding of process dynamics and control. Also discusses hardware/software and simulations developed using the system. The four simulations model various configurations of a process liquid level tank system. (JN)

System Simulation by Recursive Feedback: Coupling A Set of Stand-Alone Subsystem Simulations

NASA Technical Reports Server (NTRS)

Nixon, Douglas D.; Hanson, John M. (Technical Monitor)

2002-01-01

Recursive feedback is defined and discussed as a framework for development of specific algorithms and procedures that propagate the time-domain solution for a dynamical system simulation consisting of multiple numerically coupled self-contained stand-alone subsystem simulations. A satellite motion example containing three subsystems (other dynamics, attitude dynamics, and aerodynamics) has been defined and constructed using this approach. Conventional solution methods are used in the subsystem simulations. Centralized and distributed versions of coupling structure have been addressed. Numerical results are evaluated by direct comparison with a standard total-system simultaneous-solution approach.

Validation of Potential Models for Li2O in Classical Molecular Dynamics Simulation

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

Oda, Takuji; Oya, Yasuhisa; Tanaka, Satoru

2007-08-01

Four Buckingham-type pairwise potential models for Li2O were assessed by molecular static and dynamics simulations. In the static simulation, all models afforded acceptable agreement with experimental values and ab initio calculation results for the crystalline properties. Moreover, the superionic phase transition was realized in the dynamics simulation. However, the Li diffusivity and the lattice expansion were not adequately reproduced at the same time by any model. When using these models in future radiation simulation, these features should be taken into account, in order to reduce the model dependency of the results.

FAST Simulation Tool Containing Methods for Predicting the Dynamic Response of Wind Turbines

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

Jonkman, Jason

2015-08-12

FAST is a simulation tool (computer software) for modeling tlie dynamic response of horizontal-axis wind turbines. FAST employs a combined modal and multibody structural-dynamics formulation in the time domain.

Molecular dynamics simulation of low-energy recoil events in titanate pyrochlores

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

Dong, Liyuan; Setyawan, Wahyu; Li, Yuhong

2017-01-01

Molecular dynamics simulations of low-energy displacements in titanate pyrochlores have been carried out along three main directions, to determineE dfor A, Ti and O, corresponding defect configurations, and defect formation dynamics.

Explicit symplectic algorithms based on generating functions for relativistic charged particle dynamics in time-dependent electromagnetic field

NASA Astrophysics Data System (ADS)

Zhang, Ruili; Wang, Yulei; He, Yang; Xiao, Jianyuan; Liu, Jian; Qin, Hong; Tang, Yifa

2018-02-01

Relativistic dynamics of a charged particle in time-dependent electromagnetic fields has theoretical significance and a wide range of applications. The numerical simulation of relativistic dynamics is often multi-scale and requires accurate long-term numerical simulations. Therefore, explicit symplectic algorithms are much more preferable than non-symplectic methods and implicit symplectic algorithms. In this paper, we employ the proper time and express the Hamiltonian as the sum of exactly solvable terms and product-separable terms in space-time coordinates. Then, we give the explicit symplectic algorithms based on the generating functions of orders 2 and 3 for relativistic dynamics of a charged particle. The methodology is not new, which has been applied to non-relativistic dynamics of charged particles, but the algorithm for relativistic dynamics has much significance in practical simulations, such as the secular simulation of runaway electrons in tokamaks.

Space station dynamics, attitude control and momentum management

NASA Technical Reports Server (NTRS)

Sunkel, John W.; Singh, Ramen P.; Vengopal, Ravi

1989-01-01

The Space Station Attitude Control System software test-bed provides a rigorous environment for the design, development and functional verification of GN and C algorithms and software. The approach taken for the simulation of the vehicle dynamics and environmental models using a computationally efficient algorithm is discussed. The simulation includes capabilities for docking/berthing dynamics, prescribed motion dynamics associated with the Mobile Remote Manipulator System (MRMS) and microgravity disturbances. The vehicle dynamics module interfaces with the test-bed through the central Communicator facility which is in turn driven by the Station Control Simulator (SCS) Executive. The Communicator addresses issues such as the interface between the discrete flight software and the continuous vehicle dynamics, and multi-programming aspects such as the complex flow of control in real-time programs. Combined with the flight software and redundancy management modules, the facility provides a flexible, user-oriented simulation platform.

Supersonic Flight Dynamics Test 1 - Post-Flight Assessment of Simulation Performance

NASA Technical Reports Server (NTRS)

Dutta, Soumyo; Bowes, Angela L.; Striepe, Scott A.; Davis, Jody L.; Queen, Eric M.; Blood, Eric M.; Ivanov, Mark C.

2015-01-01

NASA's Low Density Supersonic Decelerator (LDSD) project conducted its first Supersonic Flight Dynamics Test (SFDT-1) on June 28, 2014. Program to Optimize Simulated Trajectories II (POST2) was one of the flight dynamics codes used to simulate and predict the flight performance and Monte Carlo analysis was used to characterize the potential flight conditions experienced by the test vehicle. This paper compares the simulation predictions with the reconstructed trajectory of SFDT-1. Additionally, off-nominal conditions seen during flight are modeled in post-flight simulations to find the primary contributors that reconcile the simulation with flight data. The results of these analyses are beneficial for the pre-flight simulation and targeting of the follow-on SFDT flights currently scheduled for summer 2015.

Influence of feedbacks from simulated crop growth on integrated regional hydrologic simulations under climate scenarios

NASA Astrophysics Data System (ADS)

van Walsum, P. E. V.

2011-11-01

Climate change impact modelling of hydrologic responses is hampered by climate-dependent model parameterizations. Reducing this dependency was one of the goals of extending the regional hydrologic modelling system SIMGRO with a two-way coupling to the crop growth simulation model WOFOST. The coupling includes feedbacks to the hydrologic model in terms of the root zone depth, soil cover, leaf area index, interception storage capacity, crop height and crop factor. For investigating whether such feedbacks lead to significantly different simulation results, two versions of the model coupling were set up for a test region: one with exogenous vegetation parameters, the "static" model, and one with endogenous simulation of the crop growth, the "dynamic" model WOFOST. The used parameterization methods of the static/dynamic vegetation models ensure that for the current climate the simulated long-term average of the actual evapotranspiration is the same for both models. Simulations were made for two climate scenarios. Owing to the higher temperatures in combination with a higher CO2-concentration of the atmosphere, a forward time shift of the crop development is simulated in the dynamic model; the used arable land crop, potatoes, also shows a shortening of the growing season. For this crop, a significant reduction of the potential transpiration is simulated compared to the static model, in the example by 15% in a warm, dry year. In consequence, the simulated crop water stress (the unit minus the relative transpiration) is lower when the dynamic model is used; also the simulated increase of crop water stress due to climate change is lower; in the example, the simulated increase is 15 percentage points less (of 55) than when a static model is used. The static/dynamic models also simulate different absolute values of the transpiration. The difference is most pronounced for potatoes at locations with ample moisture supply; this supply can either come from storage release of a good soil or from capillary rise. With good supply of moisture, the dynamic model simulates up to 10% less actual evapotranspiration than the static one in the example. This can lead to cases where the dynamic model predicts a slight increase of the recharge in a climate scenario, where the static model predicts a decrease. The use of a dynamic model also affects the simulated demand for surface water from external sources; especially the timing is affected. The proposed modelling approach uses postulated relationships that require validation with controlled field trials. In the Netherlands there is a lack of experimental facilities for performing such validations.

Man-in-the-control-loop simulation of manipulators

NASA Technical Reports Server (NTRS)

Chang, J. L.; Lin, Tsung-Chieh; Yae, K. Harold

1989-01-01

A method to achieve man-in-the-control-loop simulation is presented. Emerging real-time dynamics simulation suggests a potential for creating an interactive design workstation with a human operator in the control loop. The recursive formulation for multibody dynamics simulation is studied to determine requirements for man-in-the-control-loop simulation. High speed computer graphics techniques provides realistic visual cues for the simulator. Backhoe and robot arm simulations are implemented to demonstrate the capability of man-in-the-control-loop simulation.

Wavelet-based surrogate time series for multiscale simulation of heterogeneous catalysis

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

Savara, Aditya Ashi; Daw, C. Stuart; Xiong, Qingang

We propose a wavelet-based scheme that encodes the essential dynamics of discrete microscale surface reactions in a form that can be coupled with continuum macroscale flow simulations with high computational efficiency. This makes it possible to simulate the dynamic behavior of reactor-scale heterogeneous catalysis without requiring detailed concurrent simulations at both the surface and continuum scales using different models. Our scheme is based on the application of wavelet-based surrogate time series that encodes the essential temporal and/or spatial fine-scale dynamics at the catalyst surface. The encoded dynamics are then used to generate statistically equivalent, randomized surrogate time series, which canmore » be linked to the continuum scale simulation. As a result, we illustrate an application of this approach using two different kinetic Monte Carlo simulations with different characteristic behaviors typical for heterogeneous chemical reactions.« less

Molecular dynamics and dynamic Monte-Carlo simulation of irradiation damage with focused ion beams

NASA Astrophysics Data System (ADS)

Ohya, Kaoru

2017-03-01

The focused ion beam (FIB) has become an important tool for micro- and nanostructuring of samples such as milling, deposition and imaging. However, this leads to damage of the surface on the nanometer scale from implanted projectile ions and recoiled material atoms. It is therefore important to investigate each kind of damage quantitatively. We present a dynamic Monte-Carlo (MC) simulation code to simulate the morphological and compositional changes of a multilayered sample under ion irradiation and a molecular dynamics (MD) simulation code to simulate dose-dependent changes in the backscattering-ion (BSI)/secondary-electron (SE) yields of a crystalline sample. Recent progress in the codes for research to simulate the surface morphology and Mo/Si layers intermixing in an EUV lithography mask irradiated with FIBs, and the crystalline orientation effect on BSI and SE yields relating to the channeling contrast in scanning ion microscopes, is also presented.

Wavelet-based surrogate time series for multiscale simulation of heterogeneous catalysis

DOE PAGES

Savara, Aditya Ashi; Daw, C. Stuart; Xiong, Qingang; ...

2016-01-28

We propose a wavelet-based scheme that encodes the essential dynamics of discrete microscale surface reactions in a form that can be coupled with continuum macroscale flow simulations with high computational efficiency. This makes it possible to simulate the dynamic behavior of reactor-scale heterogeneous catalysis without requiring detailed concurrent simulations at both the surface and continuum scales using different models. Our scheme is based on the application of wavelet-based surrogate time series that encodes the essential temporal and/or spatial fine-scale dynamics at the catalyst surface. The encoded dynamics are then used to generate statistically equivalent, randomized surrogate time series, which canmore » be linked to the continuum scale simulation. As a result, we illustrate an application of this approach using two different kinetic Monte Carlo simulations with different characteristic behaviors typical for heterogeneous chemical reactions.« less

Ultrafast spectroscopy reveals subnanosecond peptide conformational dynamics and validates molecular dynamics simulation

NASA Astrophysics Data System (ADS)

Spörlein, Sebastian; Carstens, Heiko; Satzger, Helmut; Renner, Christian; Behrendt, Raymond; Moroder, Luis; Tavan, Paul; Zinth, Wolfgang; Wachtveitl, Josef

2002-06-01

Femtosecond time-resolved spectroscopy on model peptides with built-in light switches combined with computer simulation of light-triggered motions offers an attractive integrated approach toward the understanding of peptide conformational dynamics. It was applied to monitor the light-induced relaxation dynamics occurring on subnanosecond time scales in a peptide that was backbone-cyclized with an azobenzene derivative as optical switch and spectroscopic probe. The femtosecond spectra permit the clear distinguishing and characterization of the subpicosecond photoisomerization of the chromophore, the subsequent dissipation of vibrational energy, and the subnanosecond conformational relaxation of the peptide. The photochemical cis/trans-isomerization of the chromophore and the resulting peptide relaxations have been simulated with molecular dynamics calculations. The calculated reaction kinetics, as monitored by the energy content of the peptide, were found to match the spectroscopic data. Thus we verify that all-atom molecular dynamics simulations can quantitatively describe the subnanosecond conformational dynamics of peptides, strengthening confidence in corresponding predictions for longer time scales.

Dynamical simulation of E-ELT segmented primary mirror

NASA Astrophysics Data System (ADS)

Sedghi, B.; Muller, M.; Bauvir, B.

2011-09-01

The dynamical behavior of the primary mirror (M1) has an important impact on the control of the segments and the performance of the telescope. Control of large segmented mirrors with a large number of actuators and sensors and multiple control loops in real life is a challenging problem. In virtual life, modeling, simulation and analysis of the M1 bears similar difficulties and challenges. In order to capture the dynamics of the segment subunits (high frequency modes) and the telescope back structure (low frequency modes), high order dynamical models with a very large number of inputs and outputs need to be simulated. In this paper, different approaches for dynamical modeling and simulation of the M1 segmented mirror subject to various perturbations, e.g. sensor noise, wind load, vibrations, earthquake are presented.

Review of Dynamic Modeling and Simulation of Large Scale Belt Conveyor System

NASA Astrophysics Data System (ADS)

He, Qing; Li, Hong

Belt conveyor is one of the most important devices to transport bulk-solid material for long distance. Dynamic analysis is the key to decide whether the design is rational in technique, safe and reliable in running, feasible in economy. It is very important to study dynamic properties, improve efficiency and productivity, guarantee conveyor safe, reliable and stable running. The dynamic researches and applications of large scale belt conveyor are discussed. The main research topics, the state-of-the-art of dynamic researches on belt conveyor are analyzed. The main future works focus on dynamic analysis, modeling and simulation of main components and whole system, nonlinear modeling, simulation and vibration analysis of large scale conveyor system.

Generalized dynamic engine simulation techniques for the digital computer

NASA Technical Reports Server (NTRS)

Sellers, J.; Teren, F.

1974-01-01

Recently advanced simulation techniques have been developed for the digital computer and used as the basis for development of a generalized dynamic engine simulation computer program, called DYNGEN. This computer program can analyze the steady state and dynamic performance of many kinds of aircraft gas turbine engines. Without changes to the basic program, DYNGEN can analyze one- or two-spool turbofan engines. The user must supply appropriate component performance maps and design-point information. Examples are presented to illustrate the capabilities of DYNGEN in the steady state and dynamic modes of operation. The analytical techniques used in DYNGEN are briefly discussed, and its accuracy is compared with a comparable simulation using the hybrid computer. The impact of DYNGEN and similar all-digital programs on future engine simulation philosophy is also discussed.

Generalized dynamic engine simulation techniques for the digital computer

NASA Technical Reports Server (NTRS)

Sellers, J.; Teren, F.

1974-01-01

Recently advanced simulation techniques have been developed for the digital computer and used as the basis for development of a generalized dynamic engine simulation computer program, called DYNGEN. This computer program can analyze the steady state and dynamic performance of many kinds of aircraft gas turbine engines. Without changes to the basic program DYNGEN can analyze one- or two-spool turbofan engines. The user must supply appropriate component performance maps and design-point information. Examples are presented to illustrate the capabilities of DYNGEN in the steady state and dynamic modes of operation. The analytical techniques used in DYNGEN are briefly discussed, and its accuracy is compared with a comparable simulation using the hybrid computer. The impact of DYNGEN and similar all-digital programs on future engine simulation philosophy is also discussed.

Generalized dynamic engine simulation techniques for the digital computers

NASA Technical Reports Server (NTRS)

Sellers, J.; Teren, F.

1975-01-01

Recently advanced simulation techniques have been developed for the digital computer and used as the basis for development of a generalized dynamic engine simulation computer program, called DYNGEN. This computer program can analyze the steady state and dynamic performance of many kinds of aircraft gas turbine engines. Without changes to the basic program, DYNGEN can analyze one- or two-spool turbofan engines. The user must supply appropriate component performance maps and design point information. Examples are presented to illustrate the capabilities of DYNGEN in the steady state and dynamic modes of operation. The analytical techniques used in DYNGEN are briefly discussed, and its accuracy is compared with a comparable simulation using the hybrid computer. The impact of DYNGEN and similar digital programs on future engine simulation philosophy is also discussed.

A high performance system for molecular dynamics simulation of biomolecules using a special-purpose computer.

PubMed

Komeiji, Y; Yokoyama, H; Uebayasi, M; Taiji, M; Fukushige, T; Sugimoto, D; Takata, R; Shimizu, A; Itsukashi, K

1996-01-01

GRAPE (GRavity PipE) processors are special purpose computers for simulation of classical particles. The performance of MD-GRAPE, one of the GRAPEs developed for molecular dynamics, was investigated. The effective speed of MD-GRAPE was equivalent to approximately 6 Gflops. The precision of MD-GRAPE was good judging from the acceptable fluctuation of the total energy. Then a software named PEACH (Program for Energetic Analysis of bioCHemical molecules) was developed for molecular dynamics of biomolecules in combination with MD-GRAPE. Molecular dynamics simulation was performed for several protein-solvent systems with different sizes. Simulation of the largest system investigated (27,000 atoms) took only 5 sec/step. Thus, the PEACH-GRAPE system is expected to be useful in accurate and reliable simulation of large biomolecules.

A GPU-accelerated immersive audio-visual framework for interaction with molecular dynamics using consumer depth sensors.

PubMed

Glowacki, David R; O'Connor, Michael; Calabró, Gaetano; Price, James; Tew, Philip; Mitchell, Thomas; Hyde, Joseph; Tew, David P; Coughtrie, David J; McIntosh-Smith, Simon

2014-01-01

With advances in computational power, the rapidly growing role of computational/simulation methodologies in the physical sciences, and the development of new human-computer interaction technologies, the field of interactive molecular dynamics seems destined to expand. In this paper, we describe and benchmark the software algorithms and hardware setup for carrying out interactive molecular dynamics utilizing an array of consumer depth sensors. The system works by interpreting the human form as an energy landscape, and superimposing this landscape on a molecular dynamics simulation to chaperone the motion of the simulated atoms, affecting both graphics and sonified simulation data. GPU acceleration has been key to achieving our target of 60 frames per second (FPS), giving an extremely fluid interactive experience. GPU acceleration has also allowed us to scale the system for use in immersive 360° spaces with an array of up to ten depth sensors, allowing several users to simultaneously chaperone the dynamics. The flexibility of our platform for carrying out molecular dynamics simulations has been considerably enhanced by wrappers that facilitate fast communication with a portable selection of GPU-accelerated molecular force evaluation routines. In this paper, we describe a 360° atmospheric molecular dynamics simulation we have run in a chemistry/physics education context. We also describe initial tests in which users have been able to chaperone the dynamics of 10-alanine peptide embedded in an explicit water solvent. Using this system, both expert and novice users have been able to accelerate peptide rare event dynamics by 3-4 orders of magnitude.

Multibody dynamic simulation of knee contact mechanics

PubMed Central

Bei, Yanhong; Fregly, Benjamin J.

2006-01-01

Multibody dynamic musculoskeletal models capable of predicting muscle forces and joint contact pressures simultaneously would be valuable for studying clinical issues related to knee joint degeneration and restoration. Current three-dimensional multi-body knee models are either quasi-static with deformable contact or dynamic with rigid contact. This study proposes a computationally efficient methodology for combining multibody dynamic simulation methods with a deformable contact knee model. The methodology requires preparation of the articular surface geometry, development of efficient methods to calculate distances between contact surfaces, implementation of an efficient contact solver that accounts for the unique characteristics of human joints, and specification of an application programming interface for integration with any multibody dynamic simulation environment. The current implementation accommodates natural or artificial tibiofemoral joint models, small or large strain contact models, and linear or nonlinear material models. Applications are presented for static analysis (via dynamic simulation) of a natural knee model created from MRI and CT data and dynamic simulation of an artificial knee model produced from manufacturer’s CAD data. Small and large strain natural knee static analyses required 1 min of CPU time and predicted similar contact conditions except for peak pressure, which was higher for the large strain model. Linear and nonlinear artificial knee dynamic simulations required 10 min of CPU time and predicted similar contact force and torque but different contact pressures, which were lower for the nonlinear model due to increased contact area. This methodology provides an important step toward the realization of dynamic musculoskeletal models that can predict in vivo knee joint motion and loading simultaneously. PMID:15564115

Time scale bridging in atomistic simulation of slow dynamics: viscous relaxation and defect activation

NASA Astrophysics Data System (ADS)

Kushima, A.; Eapen, J.; Li, Ju; Yip, S.; Zhu, T.

2011-08-01

Atomistic simulation methods are known for timescale limitations in resolving slow dynamical processes. Two well-known scenarios of slow dynamics are viscous relaxation in supercooled liquids and creep deformation in stressed solids. In both phenomena the challenge to theory and simulation is to sample the transition state pathways efficiently and follow the dynamical processes on long timescales. We present a perspective based on the biased molecular simulation methods such as metadynamics, autonomous basin climbing (ABC), strain-boost and adaptive boost simulations. Such algorithms can enable an atomic-level explanation of the temperature variation of the shear viscosity of glassy liquids, and the relaxation behavior in solids undergoing creep deformation. By discussing the dynamics of slow relaxation in two quite different areas of condensed matter science, we hope to draw attention to other complex problems where anthropological or geological-scale time behavior can be simulated at atomic resolution and understood in terms of micro-scale processes of molecular rearrangements and collective interactions. As examples of a class of phenomena that can be broadly classified as materials ageing, we point to stress corrosion cracking and cement setting as opportunities for atomistic modeling and simulations.

Si amorphization by focused ion beam milling: Point defect model with dynamic BCA simulation and experimental validation.

PubMed

Huang, J; Loeffler, M; Muehle, U; Moeller, W; Mulders, J J L; Kwakman, L F Tz; Van Dorp, W F; Zschech, E

2018-01-01

A Ga focused ion beam (FIB) is often used in transmission electron microscopy (TEM) analysis sample preparation. In case of a crystalline Si sample, an amorphous near-surface layer is formed by the FIB process. In order to optimize the FIB recipe by minimizing the amorphization, it is important to predict the amorphous layer thickness from simulation. Molecular Dynamics (MD) simulation has been used to describe the amorphization, however, it is limited by computational power for a realistic FIB process simulation. On the other hand, Binary Collision Approximation (BCA) simulation is able and has been used to simulate ion-solid interaction process at a realistic scale. In this study, a Point Defect Density approach is introduced to a dynamic BCA simulation, considering dynamic ion-solid interactions. We used this method to predict the c-Si amorphization caused by FIB milling on Si. To validate the method, dedicated TEM studies are performed. It shows that the amorphous layer thickness predicted by the numerical simulation is consistent with the experimental data. In summary, the thickness of the near-surface Si amorphization layer caused by FIB milling can be well predicted using the Point Defect Density approach within the dynamic BCA model. Copyright © 2017 Elsevier B.V. All rights reserved.

Rupture Dynamics and Seismic Radiation on Rough Faults for Simulation-Based PSHA

NASA Astrophysics Data System (ADS)

Mai, P. M.; Galis, M.; Thingbaijam, K. K. S.; Vyas, J. C.; Dunham, E. M.

2017-12-01

Simulation-based ground-motion predictions may augment PSHA studies in data-poor regions or provide additional shaking estimations, incl. seismic waveforms, for critical facilities. Validation and calibration of such simulation approaches, based on observations and GMPE's, is important for engineering applications, while seismologists push to include the precise physics of the earthquake rupture process and seismic wave propagation in 3D heterogeneous Earth. Geological faults comprise both large-scale segmentation and small-scale roughness that determine the dynamics of the earthquake rupture process and its radiated seismic wavefield. We investigate how different parameterizations of fractal fault roughness affect the rupture evolution and resulting near-fault ground motions. Rupture incoherence induced by fault roughness generates realistic ω-2 decay for high-frequency displacement amplitude spectra. Waveform characteristics and GMPE-based comparisons corroborate that these rough-fault rupture simulations generate realistic synthetic seismogram for subsequent engineering application. Since dynamic rupture simulations are computationally expensive, we develop kinematic approximations that emulate the observed dynamics. Simplifying the rough-fault geometry, we find that perturbations in local moment tensor orientation are important, while perturbations in local source location are not. Thus, a planar fault can be assumed if the local strike, dip, and rake are maintained. The dynamic rake angle variations are anti-correlated with local dip angles. Based on a dynamically consistent Yoffe source-time function, we show that the seismic wavefield of the approximated kinematic rupture well reproduces the seismic radiation of the full dynamic source process. Our findings provide an innovative pseudo-dynamic source characterization that captures fault roughness effects on rupture dynamics. Including the correlations between kinematic source parameters, we present a new pseudo-dynamic rupture modeling approach for computing broadband ground-motion time-histories for simulation-based PSHA

Post-Flight Assessment of Low Density Supersonic Decelerator Flight Dynamics Test 2 Simulation

NASA Technical Reports Server (NTRS)

Dutta, Soumyo; Bowes, Angela L.; White, Joseph P.; Striepe, Scott A.; Queen, Eric M.; O'Farrel, Clara; Ivanov, Mark C.

2016-01-01

NASA's Low Density Supersonic Decelerator (LDSD) project conducted its second Supersonic Flight Dynamics Test (SFDT-2) on June 8, 2015. The Program to Optimize Simulated Trajectories II (POST2) was one of the flight dynamics tools used to simulate and predict the flight performance and was a major tool used in the post-flight assessment of the flight trajectory. This paper compares the simulation predictions with the reconstructed trajectory. Additionally, off-nominal conditions seen during flight are modeled in the simulation to reconcile the predictions with flight data. These analyses are beneficial to characterize the results of the flight test and to improve the simulation and targeting of the subsequent LDSD flights.

Novel Breast Cancer Therapeutics Based on Bacterial Cupredoxin

DTIC Science & Technology

2008-09-01

M. and Lim, C. (1999) Exploring the dynamic information content of a protein NMR structure: comparison of a molecular dynamics simulation with the...crowding has structural effects on the folded ensemble of polypeptides. energy landscape theory excluded volume effect molecular simulations protein... molecular simulations (51). Thermo- dynamic properties such as the radius of gyration (Rg), shape parameters ( and S) (11), and the fraction of native

Improved Pyrolysis Micro reactor Design via Computational Fluid Dynamics Simulations

DTIC Science & Technology

2017-05-23

Dynamics Simulations Ghanshyam L. Vaghjiani Air Force Research Laboratory (AFMC) AFRL/RQRS 1 Ara Drive Edwards AFB, CA 93524-7013 Air Force...Aerospace Systems Directorate Air Force Research Laboratory AFRL/RQRS 1 Ara Road Edwards AFB, CA 93524 *Email: ghanshyam.vaghjiani@us.af.mil IMPROVED...PYROLYSIS MICRO-REACTOR DESIGN VIA COMPUTATIONAL FLUID DYNAMICS SIMULATIONS Ghanshyam L. Vaghjiani* DISTRIBUTION A: Approved for public release

Combat Simulation Using Breach Computer Language

DTIC Science & Technology

1979-09-01

simulation and weapon system analysis computer language Two types of models were constructed: a stochastic duel and a dynamic engagement model The... duel model validates the BREACH approach by comparing results with mathematical solutions. The dynamic model shows the capability of the BREACH...BREACH 2 Background 2 The Language 3 Static Duel 4 Background and Methodology 4 Validation 5 Results 8 Tank Duel Simulation 8 Dynamic Assault Model

Control Performance, Aerodynamic Modeling, and Validation of Coupled Simulation Techniques for Guided Projectile Roll Dynamics

DTIC Science & Technology

2014-11-01

39–44) has been explored in depth in the literature. Of particular interest for this study are investigations into roll control. Isolating the...Control Performance, Aerodynamic Modeling, and Validation of Coupled Simulation Techniques for Guided Projectile Roll Dynamics by Jubaraj...Simulation Techniques for Guided Projectile Roll Dynamics Jubaraj Sahu, Frank Fresconi, and Karen R. Heavey Weapons and Materials Research

Free-Energy Profiles of Membrane Insertion of the M2 Transmembrane Peptide from Influenza A Virus

DTIC Science & Technology

2008-12-01

ABSTRACT The insertion of the M2 transmembrane peptide from influenza A virus into a membrane has been studied with molecular - dynamics simulations ...performed replica-exchange molecular - dynamics simulations with umbrella-sampling techniques to characterize the probability distribution and conformation...atomic- detailed molecular dynamics (MD) simulation techniques represent a valuable complementary methodology to inves- tigate membrane-insertion of

Study of the dynamics of poly(ethylene oxide) by combining molecular dynamic simulations and neutron scattering experiments

NASA Astrophysics Data System (ADS)

Brodeck, M.; Alvarez, F.; Arbe, A.; Juranyi, F.; Unruh, T.; Holderer, O.; Colmenero, J.; Richter, D.

2009-03-01

We performed quasielastic neutron scattering experiments and atomistic molecular dynamics simulations on a poly(ethylene oxide) (PEO) homopolymer system above the melting point. The excellent agreement found between both sets of data, together with a successful comparison with literature diffraction results, validates the condensed-phase optimized molecular potentials for atomistic simulation studies (COMPASS) force field used to produce our dynamic runs and gives support to their further analysis. This provided direct information on magnitudes which are not accessible from experiments such as the radial probability distribution functions of specific atoms at different times and their moments. The results of our simulations on the H-motions and different experiments indicate that in the high-temperature range investigated the dynamics is Rouse-like for Q-values below ≈0.6 Å-1. We then addressed the single chain dynamic structure factor with the simulations. A mode analysis, not possible directly experimentally, reveals the limits of applicability of the Rouse model to PEO. We discuss the possible origins for the observed deviations.

Study of the dynamics of poly(ethylene oxide) by combining molecular dynamic simulations and neutron scattering experiments.

PubMed

Brodeck, M; Alvarez, F; Arbe, A; Juranyi, F; Unruh, T; Holderer, O; Colmenero, J; Richter, D

2009-03-07

We performed quasielastic neutron scattering experiments and atomistic molecular dynamics simulations on a poly(ethylene oxide) (PEO) homopolymer system above the melting point. The excellent agreement found between both sets of data, together with a successful comparison with literature diffraction results, validates the condensed-phase optimized molecular potentials for atomistic simulation studies (COMPASS) force field used to produce our dynamic runs and gives support to their further analysis. This provided direct information on magnitudes which are not accessible from experiments such as the radial probability distribution functions of specific atoms at different times and their moments. The results of our simulations on the H-motions and different experiments indicate that in the high-temperature range investigated the dynamics is Rouse-like for Q-values below approximately 0.6 A(-1). We then addressed the single chain dynamic structure factor with the simulations. A mode analysis, not possible directly experimentally, reveals the limits of applicability of the Rouse model to PEO. We discuss the possible origins for the observed deviations.

An intercomparison of GCM and RCM dynamical downscaling for characterizing the hydroclimatology of California and Nevada

NASA Astrophysics Data System (ADS)

Xu, Z.; Rhoades, A.; Johansen, H.; Ullrich, P. A.; Collins, W. D.

2017-12-01

Dynamical downscaling is widely used to properly characterize regional surface heterogeneities that shape the local hydroclimatology. However, the factors in dynamical downscaling, including the refinement of model horizontal resolution, large-scale forcing datasets and dynamical cores, have not been fully evaluated. Two cutting-edge global-to-regional downscaling methods are used to assess these, specifically the variable-resolution Community Earth System Model (VR-CESM) and the Weather Research & Forecasting (WRF) regional climate model, under different horizontal resolutions (28, 14, and 7 km). Two groups of WRF simulations are driven by either the NCEP reanalysis dataset (WRF_NCEP) or VR-CESM outputs (WRF_VRCESM) to evaluate the effects of the large-scale forcing datasets. The impacts of dynamical core are assessed by comparing the VR-CESM simulations to the coupled WRF_VRCESM simulations with the same physical parameterizations and similar grid domains. The simulated hydroclimatology (i.e., total precipitation, snow cover, snow water equivalent and surface temperature) are compared with the reference datasets. The large-scale forcing datasets are critical to the WRF simulations in more accurately simulating total precipitation, SWE and snow cover, but not surface temperature. Both the WRF and VR-CESM results highlight that no significant benefit is found in the simulated hydroclimatology by just increasing horizontal resolution refinement from 28 to 7 km. Simulated surface temperature is sensitive to the choice of dynamical core. WRF generally simulates higher temperatures than VR-CESM, alleviates the systematic cold bias of DJF temperatures over the California mountain region, but overestimates the JJA temperature in California's Central Valley.

Modelling and simulation of Space Station Freedom berthing dynamics and control

NASA Technical Reports Server (NTRS)

Cooper, Paul A.; Garrison, James L., Jr.; Montgomery, Raymond C.; Wu, Shih-Chin; Stockwell, Alan E.; Demeo, Martha E.

1994-01-01

A large-angle, flexible, multibody, dynamic modeling capability has been developed to help validate numerical simulations of the dynamic motion and control forces which occur during berthing of Space Station Freedom to the Shuttle Orbiter in the early assembly flights. This paper outlines the dynamics and control of the station, the attached Shuttle Remote Manipulator System, and the orbiter. The simulation tool developed for the analysis is described and the results of two simulations are presented. The first is a simulated maneuver from a gravity-gradient attitude to a torque equilibrium attitude using the station reaction control jets. The second simulation is the berthing of the station to the orbiter with the station control moment gyros actively maintaining an estimated torque equilibrium attitude. The influence of the elastic dynamic behavior of the station and of the Remote Manipulator System on the attitude control of the station/orbiter system during each maneuver was investigated. The flexibility of the station and the arm were found to have only a minor influence on the attitude control of the system during the maneuvers.

Simulating Vibrations in a Complex Loaded Structure

NASA Technical Reports Server (NTRS)

Cao, Tim T.

2005-01-01

The Dynamic Response Computation (DIRECT) computer program simulates vibrations induced in a complex structure by applied dynamic loads. Developed to enable rapid analysis of launch- and landing- induced vibrations and stresses in a space shuttle, DIRECT also can be used to analyze dynamic responses of other structures - for example, the response of a building to an earthquake, or the response of an oil-drilling platform and attached tanks to large ocean waves. For a space-shuttle simulation, the required input to DIRECT includes mathematical models of the space shuttle and its payloads, and a set of forcing functions that simulates launch and landing loads. DIRECT can accommodate multiple levels of payload attachment and substructure as well as nonlinear dynamic responses of structural interfaces. DIRECT combines the shuttle and payload models into a single structural model, to which the forcing functions are then applied. The resulting equations of motion are reduced to an optimum set and decoupled into a unique format for simulating dynamics. During the simulation, maximum vibrations, loads, and stresses are monitored and recorded for subsequent analysis to identify structural deficiencies in the shuttle and/or payloads.

Focused and Corrective Feedback Versus Structured and Supported Debriefing in a Simulation-Based Cardiac Arrest Team Training: A Pilot Randomized Controlled Study.

PubMed

Kim, Ji-Hoon; Kim, Young-Min; Park, Seong Heui; Ju, Eun A; Choi, Se Min; Hong, Tai Yong

2017-06-01

The aim of the study was to compare the educational impact of two postsimulation debriefing methods-focused and corrective feedback (FCF) versus Structured and Supported Debriefing (SSD)-on team dynamics in simulation-based cardiac arrest team training. This was a pilot randomized controlled study conducted at a simulation center. Fourth-year medical students were randomly assigned to the FCF or SSD group, with each team composed of six students and a confederate. Each team participated in two simulations and the assigned debriefing (FCF or SSD) sessions and then underwent a test simulation. Two trained raters blindly assessed all of the recorded simulations using checklists. The primary outcome was the improvement in team dynamics scores between baseline and test simulation. The secondary outcomes were improvements before and after training in team clinical performance scores, self-assessed comprehension of and confidence in cardiac arrest management and team dynamics, as well as evaluations of the postsimulation debriefing intervention. In total, 95 students participated [FCF (8 teams, n = 47) and SSD (8 teams, n = 48)]. The SSD team dynamics score during the test simulation was higher than at baseline [baseline: 74.5 (65.9-80.9), test: 85.0 (71.9-87.6), P = 0.035]. However, there were no differences in the improvement in the team dynamics or team clinical performance scores between the two groups (P = 0.328, respectively). There was no significant difference in improvement in team dynamics scores during the test simulation compared with baseline between the SSD and FCF groups in a simulation-based cardiac arrest team training in fourth-year Korean medical students.

Prediction and validation of diffusion coefficients in a model drug delivery system using microsecond atomistic molecular dynamics simulation and vapour sorption analysis.

PubMed

Forrey, Christopher; Saylor, David M; Silverstein, Joshua S; Douglas, Jack F; Davis, Eric M; Elabd, Yossef A

2014-10-14

Diffusion of small to medium sized molecules in polymeric medical device materials underlies a broad range of public health concerns related to unintended leaching from or uptake into implantable medical devices. However, obtaining accurate diffusion coefficients for such systems at physiological temperature represents a formidable challenge, both experimentally and computationally. While molecular dynamics simulation has been used to accurately predict the diffusion coefficients, D, of a handful of gases in various polymers, this success has not been extended to molecules larger than gases, e.g., condensable vapours, liquids, and drugs. We present atomistic molecular dynamics simulation predictions of diffusion in a model drug eluting system that represent a dramatic improvement in accuracy compared to previous simulation predictions for comparable systems. We find that, for simulations of insufficient duration, sub-diffusive dynamics can lead to dramatic over-prediction of D. We present useful metrics for monitoring the extent of sub-diffusive dynamics and explore how these metrics correlate to error in D. We also identify a relationship between diffusion and fast dynamics in our system, which may serve as a means to more rapidly predict diffusion in slowly diffusing systems. Our work provides important precedent and essential insights for utilizing atomistic molecular dynamics simulations to predict diffusion coefficients of small to medium sized molecules in condensed soft matter systems.

Troubleshooting Instruction in Vocational-Technical Education Via Dynamic Simulation. Final Report.

ERIC Educational Resources Information Center

Finch, Curtis R.

This study was designed to examine the feasibility of using simulation as a means of teaching vocational-technical students to detect and identify malfunctions in selected electrical and mechanical systems. A dynamic simulator was employed which features interchangeable panels and logic that permits the simulation of electrical or mechanical…

Towards a comprehensive framework for cosimulation of dynamic models with an emphasis on time stepping

NASA Astrophysics Data System (ADS)

Hoepfer, Matthias

Over the last two decades, computer modeling and simulation have evolved as the tools of choice for the design and engineering of dynamic systems. With increased system complexities, modeling and simulation become essential enablers for the design of new systems. Some of the advantages that modeling and simulation-based system design allows for are the replacement of physical tests to ensure product performance, reliability and quality, the shortening of design cycles due to the reduced need for physical prototyping, the design for mission scenarios, the invoking of currently nonexisting technologies, and the reduction of technological and financial risks. Traditionally, dynamic systems are modeled in a monolithic way. Such monolithic models include all the data, relations and equations necessary to represent the underlying system. With increased complexity of these models, the monolithic model approach reaches certain limits regarding for example, model handling and maintenance. Furthermore, while the available computer power has been steadily increasing according to Moore's Law (a doubling in computational power every 10 years), the ever-increasing complexities of new models have negated the increased resources available. Lastly, modern systems and design processes are interdisciplinary, enforcing the necessity to make models more flexible to be able to incorporate different modeling and design approaches. The solution to bypassing the shortcomings of monolithic models is cosimulation. In a very general sense, co-simulation addresses the issue of linking together different dynamic sub-models to a model which represents the overall, integrated dynamic system. It is therefore an important enabler for the design of interdisciplinary, interconnected, highly complex dynamic systems. While a basic co-simulation setup can be very easy, complications can arise when sub-models display behaviors such as algebraic loops, singularities, or constraints. This work frames the co-simulation approach to modeling and simulation. It lays out the general approach to dynamic system co-simulation, and gives a comprehensive overview of what co-simulation is and what it is not. It creates a taxonomy of the requirements and limits of co-simulation, and the issues arising with co-simulating sub-models. Possible solutions towards resolving the stated problems are investigated to a certain depth. A particular focus is given to the issue of time stepping. It will be shown that for dynamic models, the selection of the simulation time step is a crucial issue with respect to computational expense, simulation accuracy, and error control. The reasons for this are discussed in depth, and a time stepping algorithm for co-simulation with unknown dynamic sub-models is proposed. Motivations and suggestions for the further treatment of selected issues are presented.

Microsecond Simulations of DNA and Ion Transport in Nanopores with Novel Ion-Ion and Ion-Nucleotides Effective Potentials

PubMed Central

De Biase, Pablo M.; Markosyan, Suren; Noskov, Sergei

2014-01-01

We developed a novel scheme based on the Grand-Canonical Monte-Carlo/Brownian Dynamics (GCMC/BD) simulations and have extended it to studies of ion currents across three nanopores with the potential for ssDNA sequencing: solid-state nanopore Si3N4, α-hemolysin, and E111N/M113Y/K147N mutant. To describe nucleotide-specific ion dynamics compatible with ssDNA coarse-grained model, we used the Inverse Monte-Carlo protocol, which maps the relevant ion-nucleotide distribution functions from an all-atom MD simulations. Combined with the previously developed simulation platform for Brownian Dynamic (BD) simulations of ion transport, it allows for microsecond- and millisecond-long simulations of ssDNA dynamics in nanopore with a conductance computation accuracy that equals or exceeds that of all-atom MD simulations. In spite of the simplifications, the protocol produces results that agree with the results of previous studies on ion conductance across open channels and provide direct correlations with experimentally measured blockade currents and ion conductances that have been estimated from all-atom MD simulations. PMID:24738152

Model structure identification for wastewater treatment simulation based on computational fluid dynamics.

PubMed

Alex, J; Kolisch, G; Krause, K

2002-01-01

The objective of this presented project is to use the results of an CFD simulation to automatically, systematically and reliably generate an appropriate model structure for simulation of the biological processes using CSTR activated sludge compartments. Models and dynamic simulation have become important tools for research but also increasingly for the design and optimisation of wastewater treatment plants. Besides the biological models several cases are reported about the application of computational fluid dynamics ICFD) to wastewater treatment plants. One aim of the presented method to derive model structures from CFD results is to exclude the influence of empirical structure selection to the result of dynamic simulations studies of WWTPs. The second application of the approach developed is the analysis of badly performing treatment plants where the suspicion arises that bad flow behaviour such as short cut flows is part of the problem. The method suggested requires as the first step the calculation of fluid dynamics of the biological treatment step at different loading situations by use of 3-dimensional CFD simulation. The result of this information is used to generate a suitable model structure for conventional dynamic simulation of the treatment plant by use of a number of CSTR modules with a pattern of exchange flows between the tanks automatically. The method is explained in detail and the application to the WWTP Wuppertal Buchenhofen is presented.

Use of multiple picosecond high-mass molecular dynamics simulations to predict crystallographic B-factors of folded globular proteins.

PubMed

Pang, Yuan-Ping

2016-09-01

Predicting crystallographic B-factors of a protein from a conventional molecular dynamics simulation is challenging, in part because the B-factors calculated through sampling the atomic positional fluctuations in a picosecond molecular dynamics simulation are unreliable, and the sampling of a longer simulation yields overly large root mean square deviations between calculated and experimental B-factors. This article reports improved B-factor prediction achieved by sampling the atomic positional fluctuations in multiple picosecond molecular dynamics simulations that use uniformly increased atomic masses by 100-fold to increase time resolution. Using the third immunoglobulin-binding domain of protein G, bovine pancreatic trypsin inhibitor, ubiquitin, and lysozyme as model systems, the B-factor root mean square deviations (mean ± standard error) of these proteins were 3.1 ± 0.2-9 ± 1 Å 2 for Cα and 7.3 ± 0.9-9.6 ± 0.2 Å 2 for Cγ, when the sampling was done for each of these proteins over 20 distinct, independent, and 50-picosecond high-mass molecular dynamics simulations with AMBER forcefield FF12MC or FF14SB. These results suggest that sampling the atomic positional fluctuations in multiple picosecond high-mass molecular dynamics simulations may be conducive to a priori prediction of crystallographic B-factors of a folded globular protein.

From laws of inference to protein folding dynamics.

PubMed

Tseng, Chih-Yuan; Yu, Chun-Ping; Lee, H C

2010-08-01

Protein folding dynamics is one of major issues constantly investigated in the study of protein functions. The molecular dynamic (MD) simulation with the replica exchange method (REM) is a common theoretical approach considered. Yet a trade-off in applying the REM is that the dynamics toward the native configuration in the simulations seems lost. In this work, we show that given REM-MD simulation results, protein folding dynamics can be directly derived from laws of inference. The applicability of the resulting approach, the entropic folding dynamics, is illustrated by investigating a well-studied Trp-cage peptide. Our results are qualitatively comparable with those from other studies. The current studies suggest that the incorporation of laws of inference and physics brings in a comprehensive perspective on exploring the protein folding dynamics.

Applying Parallel Adaptive Methods with GeoFEST/PYRAMID to Simulate Earth Surface Crustal Dynamics

NASA Technical Reports Server (NTRS)

Norton, Charles D.; Lyzenga, Greg; Parker, Jay; Glasscoe, Margaret; Donnellan, Andrea; Li, Peggy

2006-01-01

This viewgraph presentation reviews the use Adaptive Mesh Refinement (AMR) in simulating the Crustal Dynamics of Earth's Surface. AMR simultaneously improves solution quality, time to solution, and computer memory requirements when compared to generating/running on a globally fine mesh. The use of AMR in simulating the dynamics of the Earth's Surface is spurred by future proposed NASA missions, such as InSAR for Earth surface deformation and other measurements. These missions will require support for large-scale adaptive numerical methods using AMR to model observations. AMR was chosen because it has been successful in computation fluid dynamics for predictive simulation of complex flows around complex structures.

Easy GROMACS: A Graphical User Interface for GROMACS Molecular Dynamics Simulation Package

NASA Astrophysics Data System (ADS)

Dizkirici, Ayten; Tekpinar, Mustafa

2015-03-01

GROMACS is a widely used molecular dynamics simulation package. Since it is a command driven program, it is difficult to use this program for molecular biologists, biochemists, new graduate students and undergraduate researchers who are interested in molecular dynamics simulations. To alleviate the problem for those researchers, we wrote a graphical user interface that simplifies protein preparation for a classical molecular dynamics simulation. Our program can work with various GROMACS versions and it can perform essential analyses of GROMACS trajectories as well as protein preparation. We named our open source program `Easy GROMACS'. Easy GROMACS can give researchers more time for scientific research instead of dealing with technical intricacies.

Insights from molecular dynamics simulations for computational protein design.

PubMed

Childers, Matthew Carter; Daggett, Valerie

2017-02-01

A grand challenge in the field of structural biology is to design and engineer proteins that exhibit targeted functions. Although much success on this front has been achieved, design success rates remain low, an ever-present reminder of our limited understanding of the relationship between amino acid sequences and the structures they adopt. In addition to experimental techniques and rational design strategies, computational methods have been employed to aid in the design and engineering of proteins. Molecular dynamics (MD) is one such method that simulates the motions of proteins according to classical dynamics. Here, we review how insights into protein dynamics derived from MD simulations have influenced the design of proteins. One of the greatest strengths of MD is its capacity to reveal information beyond what is available in the static structures deposited in the Protein Data Bank. In this regard simulations can be used to directly guide protein design by providing atomistic details of the dynamic molecular interactions contributing to protein stability and function. MD simulations can also be used as a virtual screening tool to rank, select, identify, and assess potential designs. MD is uniquely poised to inform protein design efforts where the application requires realistic models of protein dynamics and atomic level descriptions of the relationship between dynamics and function. Here, we review cases where MD simulations was used to modulate protein stability and protein function by providing information regarding the conformation(s), conformational transitions, interactions, and dynamics that govern stability and function. In addition, we discuss cases where conformations from protein folding/unfolding simulations have been exploited for protein design, yielding novel outcomes that could not be obtained from static structures.

Insights from molecular dynamics simulations for computational protein design

PubMed Central

Childers, Matthew Carter; Daggett, Valerie

2017-01-01

A grand challenge in the field of structural biology is to design and engineer proteins that exhibit targeted functions. Although much success on this front has been achieved, design success rates remain low, an ever-present reminder of our limited understanding of the relationship between amino acid sequences and the structures they adopt. In addition to experimental techniques and rational design strategies, computational methods have been employed to aid in the design and engineering of proteins. Molecular dynamics (MD) is one such method that simulates the motions of proteins according to classical dynamics. Here, we review how insights into protein dynamics derived from MD simulations have influenced the design of proteins. One of the greatest strengths of MD is its capacity to reveal information beyond what is available in the static structures deposited in the Protein Data Bank. In this regard simulations can be used to directly guide protein design by providing atomistic details of the dynamic molecular interactions contributing to protein stability and function. MD simulations can also be used as a virtual screening tool to rank, select, identify, and assess potential designs. MD is uniquely poised to inform protein design efforts where the application requires realistic models of protein dynamics and atomic level descriptions of the relationship between dynamics and function. Here, we review cases where MD simulations was used to modulate protein stability and protein function by providing information regarding the conformation(s), conformational transitions, interactions, and dynamics that govern stability and function. In addition, we discuss cases where conformations from protein folding/unfolding simulations have been exploited for protein design, yielding novel outcomes that could not be obtained from static structures. PMID:28239489

Virtual Habitat -a dynamic simulation of closed life support systems -human model status

NASA Astrophysics Data System (ADS)

Markus Czupalla, M. Sc.; Zhukov, Anton; Hwang, Su-Au; Schnaitmann, Jonas

In order to optimize Life Support Systems on a system level, stability questions must be in-vestigated. To do so the exploration group of the Technical University of Munich (TUM) is developing the "Virtual Habitat" (V-HAB) dynamic LSS simulation software. V-HAB shall provide the possibility to conduct dynamic simulations of entire mission scenarios for any given LSS configuration. The Virtual Habitat simulation tool consists of four main modules: • Closed Environment Module (CEM) -monitoring of compounds in a closed environment • Crew Module (CM) -dynamic human simulation • P/C Systems Module (PCSM) -dynamic P/C subsystems • Plant Module (PM) -dynamic plant simulation The core module of the simulation is the dynamic and environment sensitive human module. Introduced in its basic version in 2008, the human module has been significantly updated since, increasing its capabilities and maturity significantly. In this paper three newly added human model subsystems (thermal regulation, digestion and schedule controller) are introduced touching also on the human stress subsystem which is cur-rently under development. Upon the introduction of these new subsystems, the integration of these into the overall V-HAB human model is discussed, highlighting the impact on the most important I/F. The overall human model capabilities shall further be summarized and presented based on meaningful test cases. In addition to the presentation of the results, the correlation strategy for the Virtual Habitat human model shall be introduced assessing the models current confidence level and giving an outlook on the future correlation strategy. Last but not least, the remaining V-HAB mod-ules shall be introduced shortly showing how the human model is integrated into the overall simulation.

Parallel Performance of Linear Solvers and Preconditioners

DTIC Science & Technology

2014-01-01

are produced by a discrete dislocation dynamics ( DDD ) simulation and change with each timestep of the DDD simulation as the dislocation structure...evolves. However, the coefficient—or stiffness matrix— remains constant during the DDD simulation and some expensive matrix factorizations only occur once...discrete dislocation dynamics ( DDD ) simulations. This can be achieved by coupling a DDD simulator for bulk material (Arsenlis et al., 2007) to a

Dynamical properties of magnetized two-dimensional one-component plasma

NASA Astrophysics Data System (ADS)

Dubey, Girija S.; Gumbs, Godfrey; Fessatidis, Vassilios

2018-05-01

Molecular dynamics simulation are used to examine the effect of a uniform perpendicular magnetic field on a two-dimensional interacting electron system. In this simulation we include the effect of the magnetic field classically through the Lorentz force. Both the Coulomb and the magnetic forces are included directly in the electron dynamics to study their combined effect on the dynamical properties of the 2D system. Results are presented for the velocity autocorrelation function and the diffusion constants in the presence and absence of an external magnetic field. Our simulation results clearly show that the external magnetic field has an effect on the dynamical properties of the system.

A comparison of East Asian summer monsoon simulations from CAM3.1 with three dynamic cores

NASA Astrophysics Data System (ADS)

Wei, Ting; Wang, Lanning; Dong, Wenjie; Dong, Min; Zhang, Jingyong

2011-12-01

This paper examines the sensitivity of CAM3.1 simulations of East Asian summer monsoon (EASM) to the choice of dynamic cores using three long-term simulations, one with each of the following cores: the Eulerian spectral transform method (EUL), semi-Lagrangian scheme (SLD) and finite volume approach (FV). Our results indicate that the dynamic cores significantly influence the simulated fields not only through dynamics, such as wind, but also through physical processes, such as precipitation. Generally speaking, SLD is superior to EUL and FV in simulating the climatological features of EASM and its interannual variability. The SLD version of the CAM model partially reduces its known deficiency in simulating the climatological features of East Asian summer precipitation. The strength and position of simulated western Pacific subtropical high (WPSH) and its ridge line compare more favourably with observations in SLD and FV than in EUL. They contribute to the intensification of the south-easterly along the south of WPSH and the vertical motion through the troposphere around 30° N, where the subtropical rain belt exists. Additionally, SLD simulates the scope of the westerly jet core over East Asia more realistically than the other two dynamic cores do. Considerable systematic errors of the seasonal migration of monsoon rain belt and water vapour flux exist in all of the three versions of CAM3.1 model, although it captures the broad northward shift of convection, and the simulated results share similarities. The interannual variation of EASM is found to be more accurate in SLD simulation, which reasonably reproduces the leading combined patterns of precipitation and 850-hPa winds in East Asia, as well as the 2.5- and 10-year periods of Li-Zeng EASM index. These results emphasise the importance of dynamic cores for the EASM simulation as distinct from the simulation's sensitivity to the physical parameterisations.

Cluster growth mechanisms in Lennard-Jones fluids: A comparison between molecular dynamics and Brownian dynamics simulations

NASA Astrophysics Data System (ADS)

Jung, Jiyun; Lee, Jumin; Kim, Jun Soo

2015-03-01

We present a simulation study on the mechanisms of a phase separation in dilute fluids of Lennard-Jones (LJ) particles as a model of self-interacting molecules. Molecular dynamics (MD) and Brownian dynamics (BD) simulations of the LJ fluids are employed to model the condensation of a liquid droplet in the vapor phase and the mesoscopic aggregation in the solution phase, respectively. With emphasis on the cluster growth at late times well beyond the nucleation stage, we find that the growth mechanisms can be qualitatively different: cluster diffusion and coalescence in the MD simulations and Ostwald ripening in the BD simulations. We also show that the rates of the cluster growth have distinct scaling behaviors during cluster growth. This work suggests that in the solution phase the random Brownian nature of the solute dynamics may lead to the Ostwald ripening that is qualitatively different from the cluster coalescence in the vapor phase.

Protocols for Molecular Dynamics Simulations of RNA Nanostructures.

PubMed

Kim, Taejin; Kasprzak, Wojciech K; Shapiro, Bruce A

2017-01-01

Molecular dynamics (MD) simulations have been used as one of the main research tools to study a wide range of biological systems and bridge the gap between X-ray crystallography or NMR structures and biological mechanism. In the field of RNA nanostructures, MD simulations have been used to fix steric clashes in computationally designed RNA nanostructures, characterize the dynamics, and investigate the interaction between RNA and other biomolecules such as delivery agents and membranes.In this chapter we present examples of computational protocols for molecular dynamics simulations in explicit and implicit solvent using the Amber Molecular Dynamics Package. We also show examples of post-simulation analysis steps and briefly mention selected tools beyond the Amber package. Limitations of the methods, tools, and protocols are also discussed. Most of the examples are illustrated for a small RNA duplex (helix), but the protocols are applicable to any nucleic acid structure, subject only to the computational speed and memory limitations of the hardware available to the user.

ChainMail based neural dynamics modeling of soft tissue deformation for surgical simulation.

PubMed

Zhang, Jinao; Zhong, Yongmin; Smith, Julian; Gu, Chengfan

2017-07-20

Realistic and real-time modeling and simulation of soft tissue deformation is a fundamental research issue in the field of surgical simulation. In this paper, a novel cellular neural network approach is presented for modeling and simulation of soft tissue deformation by combining neural dynamics of cellular neural network with ChainMail mechanism. The proposed method formulates the problem of elastic deformation into cellular neural network activities to avoid the complex computation of elasticity. The local position adjustments of ChainMail are incorporated into the cellular neural network as the local connectivity of cells, through which the dynamic behaviors of soft tissue deformation are transformed into the neural dynamics of cellular neural network. Experiments demonstrate that the proposed neural network approach is capable of modeling the soft tissues' nonlinear deformation and typical mechanical behaviors. The proposed method not only improves ChainMail's linear deformation with the nonlinear characteristics of neural dynamics but also enables the cellular neural network to follow the principle of continuum mechanics to simulate soft tissue deformation.

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

Noe, F; Diadone, Isabella; Lollmann, Marc

There is a gap between kinetic experiment and simulation in their views of the dynamics of complex biomolecular systems. Whereas experiments typically reveal only a few readily discernible exponential relaxations, simulations often indicate complex multistate behavior. Here, a theoretical framework is presented that reconciles these two approaches. The central concept is dynamical fingerprints which contain peaks at the time scales of the dynamical processes involved with amplitudes determined by the experimental observable. Fingerprints can be generated from both experimental and simulation data, and their comparison by matching peaks permits assignment of structural changes present in the simulation to experimentally observedmore » relaxation processes. The approach is applied here to a test case interpreting single molecule fluorescence correlation spectroscopy experiments on a set of fluorescent peptides with molecular dynamics simulations. The peptides exhibit complex kinetics shown to be consistent with the apparent simplicity of the experimental data. Moreover, the fingerprint approach can be used to design new experiments with site-specific labels that optimally probe specific dynamical processes in the molecule under investigation.« less

Is an intuitive convergence definition of molecular dynamics simulations solely based on the root mean square deviation possible?

PubMed

Knapp, B; Frantal, S; Cibena, M; Schreiner, W; Bauer, P

2011-08-01

Molecular dynamics is a commonly used technique in computational biology. One key issue of each molecular dynamics simulation is: When does this simulation reach equilibrium state? A widely used way to determine this is the visual and intuitive inspection of root mean square deviation (RMSD) plots of the simulation. Although this technique has been criticized several times, it is still often used. Therefore, we present a study proving that this method is not reliable at all. We conducted a survey with participants from the field in which we illustrated different RMSD plots to scientists in the field of molecular dynamics. These plots were randomized and repeated, using a statistical model and different variants of the plots. We show that there is no mutual consent about the point of equilibrium. The decisions are severely biased by different parameters. Therefore, we conclude that scientists should not discuss the equilibration of a molecular dynamics simulation on the basis of a RMSD plot.

Determination and Control of Optical and X-Ray Wave Fronts

NASA Technical Reports Server (NTRS)

Kim, Young K.

1997-01-01

A successful design of a space-based or ground optical system requires an iterative procedure which includes the kinematics and dynamics of the system in operating environment, control synthesis and verification. To facilitate the task of designing optical wave front control systems being developed at NASA/MSFC, a multi-discipline dynamics and control tool has been developed by utilizing TREETOPS, a multi-body dynamics and control simulation, NASTRAN and MATLAB. Dynamics and control models of STABLE and ARIS were developed for TREETOPS simulation, and their simulation results are documented in this report.

Mesoscopic modelling and simulation of soft matter.

PubMed

Schiller, Ulf D; Krüger, Timm; Henrich, Oliver

2017-12-20

The deformability of soft condensed matter often requires modelling of hydrodynamical aspects to gain quantitative understanding. This, however, requires specialised methods that can resolve the multiscale nature of soft matter systems. We review a number of the most popular simulation methods that have emerged, such as Langevin dynamics, dissipative particle dynamics, multi-particle collision dynamics, sometimes also referred to as stochastic rotation dynamics, and the lattice-Boltzmann method. We conclude this review with a short glance at current compute architectures for high-performance computing and community codes for soft matter simulation.

Molecular dynamics simulations: advances and applications

PubMed Central

Hospital, Adam; Goñi, Josep Ramon; Orozco, Modesto; Gelpí, Josep L

2015-01-01

Molecular dynamics simulations have evolved into a mature technique that can be used effectively to understand macromolecular structure-to-function relationships. Present simulation times are close to biologically relevant ones. Information gathered about the dynamic properties of macromolecules is rich enough to shift the usual paradigm of structural bioinformatics from studying single structures to analyze conformational ensembles. Here, we describe the foundations of molecular dynamics and the improvements made in the direction of getting such ensemble. Specific application of the technique to three main issues (allosteric regulation, docking, and structure refinement) is discussed. PMID:26604800

Simulations of Operation Dynamics of Different Type GaN Particle Sensors

PubMed Central

Gaubas, Eugenijus; Ceponis, Tomas; Kalesinskas, Vidas; Pavlov, Jevgenij; Vysniauskas, Juozas

2015-01-01

The operation dynamics of the capacitor-type and PIN diode type detectors based on GaN have been simulated using the dynamic and drift-diffusion models. The drift-diffusion current simulations have been implemented by employing the software package Synopsys TCAD Sentaurus. The monopolar and bipolar drift regimes have been analyzed by using dynamic models based on the Shockley-Ramo theorem. The carrier multiplication processes determined by impact ionization have been considered in order to compensate carrier lifetime reduction due to introduction of radiation defects into GaN detector material. PMID:25751080

Movement Characteristics Analysis and Dynamic Simulation of Collaborative Measuring Robot

NASA Astrophysics Data System (ADS)

guoqing, MA; li, LIU; zhenglin, YU; guohua, CAO; yanbin, ZHENG

2017-03-01

Human-machine collaboration is becoming increasingly more necessary, and so collaborative robot applications are also in high demand. We selected a UR10 robot as our research subject for this study. First, we applied D-H coordinate transformation of the robot to establish a link system, and we then used inverse transformation to solve the robot’s inverse kinematics and find all the joints. Use Lagrange method to analysis UR robot dynamics; use ADAMS multibody dynamics simulation software to dynamic simulation; verifying the correctness of the derived kinetic models.

System Dynamics Modeling for Supply Chain Information Sharing

NASA Astrophysics Data System (ADS)

Feng, Yang

In this paper, we try to use the method of system dynamics to model supply chain information sharing. Firstly, we determine the model boundaries, establish system dynamics model of supply chain before information sharing, analyze the model's simulation results under different changed parameters and suggest improvement proposal. Then, we establish system dynamics model of supply chain information sharing and make comparison and analysis on the two model's simulation results, to show the importance of information sharing in supply chain management. We wish that all these simulations would provide scientific supports for enterprise decision-making.

Dynamic Shade and Irradiance Simulation of Aquatic Landscapes and Watersheds

EPA Science Inventory

Penumbra is a landscape shade and irradiance simulation model that simulates how solar energy spatially and temporally interacts within dynamic ecosystems such as riparian zones, forests, and other terrain that cast topological shadows. Direct and indirect solar energy accumulate...

Dynamic extension of the Simulation Problem Analysis Kernel (SPANK)

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

Sowell, E.F.; Buhl, W.F.

1988-07-15

The Simulation Problem Analysis Kernel (SPANK) is an object-oriented simulation environment for general simulation purposes. Among its unique features is use of the directed graph as the primary data structure, rather than the matrix. This allows straightforward use of graph algorithms for matching variables and equations, and reducing the problem graph for efficient numerical solution. The original prototype implementation demonstrated the principles for systems of algebraic equations, allowing simulation of steady-state, nonlinear systems (Sowell 1986). This paper describes how the same principles can be extended to include dynamic objects, allowing simulation of general dynamic systems. The theory is developed andmore » an implementation is described. An example is taken from the field of building energy system simulation. 2 refs., 9 figs.« less

Molecular Dynamics Simulations of Nucleic Acids. From Tetranucleotides to the Ribosome.

PubMed

Šponer, Jiří; Banáš, Pavel; Jurečka, Petr; Zgarbová, Marie; Kührová, Petra; Havrila, Marek; Krepl, Miroslav; Stadlbauer, Petr; Otyepka, Michal

2014-05-15

We present a brief overview of explicit solvent molecular dynamics (MD) simulations of nucleic acids. We explain physical chemistry limitations of the simulations, namely, the molecular mechanics (MM) force field (FF) approximation and limited time scale. Further, we discuss relations and differences between simulations and experiments, compare standard and enhanced sampling simulations, discuss the role of starting structures, comment on different versions of nucleic acid FFs, and relate MM computations with contemporary quantum chemistry. Despite its limitations, we show that MD is a powerful technique for studying the structural dynamics of nucleic acids with a fast growing potential that substantially complements experimental results and aids their interpretation.

Open-source framework for power system transmission and distribution dynamics co-simulation

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

Huang, Renke; Fan, Rui; Daily, Jeff

The promise of the smart grid entails more interactions between the transmission and distribution networks, and there is an immediate need for tools to provide the comprehensive modelling and simulation required to integrate operations at both transmission and distribution levels. Existing electromagnetic transient simulators can perform simulations with integration of transmission and distribution systems, but the computational burden is high for large-scale system analysis. For transient stability analysis, currently there are only separate tools for simulating transient dynamics of the transmission and distribution systems. In this paper, we introduce an open source co-simulation framework “Framework for Network Co-Simulation” (FNCS), togethermore » with the decoupled simulation approach that links existing transmission and distribution dynamic simulators through FNCS. FNCS is a middleware interface and framework that manages the interaction and synchronization of the transmission and distribution simulators. Preliminary testing results show the validity and capability of the proposed open-source co-simulation framework and the decoupled co-simulation methodology.« less

Molecular Dynamics Simulations of the Temperature Induced Unfolding of Crambin Follow the Arrhenius Equation.

PubMed

Dalby, Andrew; Shamsir, Mohd Shahir

2015-01-01

Molecular dynamics simulations have been used extensively to model the folding and unfolding of proteins. The rates of folding and unfolding should follow the Arrhenius equation over a limited range of temperatures. This study shows that molecular dynamic simulations of the unfolding of crambin between 500K and 560K do follow the Arrhenius equation. They also show that while there is a large amount of variation between the simulations the average values for the rate show a very high degree of correlation.

Molecular Dynamics Simulations of the Temperature Induced Unfolding of Crambin Follow the Arrhenius Equation.

PubMed Central

Dalby, Andrew; Shamsir, Mohd Shahir

2015-01-01

Molecular dynamics simulations have been used extensively to model the folding and unfolding of proteins. The rates of folding and unfolding should follow the Arrhenius equation over a limited range of temperatures. This study shows that molecular dynamic simulations of the unfolding of crambin between 500K and 560K do follow the Arrhenius equation. They also show that while there is a large amount of variation between the simulations the average values for the rate show a very high degree of correlation. PMID:26539292

AceCloud: Molecular Dynamics Simulations in the Cloud.

PubMed

Harvey, M J; De Fabritiis, G

2015-05-26

We present AceCloud, an on-demand service for molecular dynamics simulations. AceCloud is designed to facilitate the secure execution of large ensembles of simulations on an external cloud computing service (currently Amazon Web Services). The AceCloud client, integrated into the ACEMD molecular dynamics package, provides an easy-to-use interface that abstracts all aspects of interaction with the cloud services. This gives the user the experience that all simulations are running on their local machine, minimizing the learning curve typically associated with the transition to using high performance computing services.

Development of a Computational Assay for the Estrogen Receptor

DTIC Science & Technology

2006-07-01

University Ashley Deline, Senior Thesis in chemistry, " Molecular Dynamic Simulations of a Glycoform and its Constituent Parts Related to Rheumatoid Arthritis...involves running a long molecular dynamics (MD) simulation of the uncoupled receptor in order to sample the protein’s unique conformations. The second...Receptor binding domain. * Performed several long molecular dynamics simulations (800 ps - 3 ns) on the ligand-ER system using ligands with known

New Finite Element/Multibody System Algorithm for Modeling Flexible Tracked Vehicles

DTIC Science & Technology

2011-08-01

U.S. Army RDECOM-TARDEC & 2 University of Illinois at Chicago ABSTRACT The dynamic simulation of multibody tracked vehicles offers engineers a...bodies. Then in a follow-on structural analysis, the loads from the multibody dynamic simulation are input to calculate strains and stresses within the...multibody dynamic simulation environment allowing for an integrated solution. In addition, a new formulation for the interaction between the rigid sprocket

In Silico Analyses of Substrate Interactions with Human Serum Paraoxonase 1

DTIC Science & Technology

2008-01-01

substrate interactions of HuPON1 remains elusive. In this study, we apply homology modeling, docking, and molecular dynamic (MD) simulations to probe the...mod- eling; docking; molecular dynamics simulations ; binding free energy decomposition. 486 PROTEINS Published 2008 WILEY-LISS, INC. yThis article is a...apply homology modeling, docking, and molecular dynamic (MD) simulations to probe the binding interactions of HuPON1 with representative substrates. The

Predictions of Crystal Structures from First Principles

DTIC Science & Technology

2007-06-01

RDX crystal in hoped that the problem could be resolved by the molecular dynamics simulations . The fully ab initio development of density functional... Molecular Dynamics Simulations of RDX i.e., without any use of experimental results (except that Crystal the geometry of monomers was derived from X-ray...applied in molecular dynamics simulations of the RDX system, due to its size, is intractable by any high-level ab crystal. We performed isothermal

A reduced basis method for molecular dynamics simulation

NASA Astrophysics Data System (ADS)

Vincent-Finley, Rachel Elisabeth

In this dissertation, we develop a method for molecular simulation based on principal component analysis (PCA) of a molecular dynamics trajectory and least squares approximation of a potential energy function. Molecular dynamics (MD) simulation is a computational tool used to study molecular systems as they evolve through time. With respect to protein dynamics, local motions, such as bond stretching, occur within femtoseconds, while rigid body and large-scale motions, occur within a range of nanoseconds to seconds. To capture motion at all levels, time steps on the order of a femtosecond are employed when solving the equations of motion and simulations must continue long enough to capture the desired large-scale motion. To date, simulations of solvated proteins on the order of nanoseconds have been reported. It is typically the case that simulations of a few nanoseconds do not provide adequate information for the study of large-scale motions. Thus, the development of techniques that allow longer simulation times can advance the study of protein function and dynamics. In this dissertation we use principal component analysis (PCA) to identify the dominant characteristics of an MD trajectory and to represent the coordinates with respect to these characteristics. We augment PCA with an updating scheme based on a reduced representation of a molecule and consider equations of motion with respect to the reduced representation. We apply our method to butane and BPTI and compare the results to standard MD simulations of these molecules. Our results indicate that the molecular activity with respect to our simulation method is analogous to that observed in the standard MD simulation with simulations on the order of picoseconds.

Angiographic analysis for phantom simulations of endovascular aneurysm treatments with a new fully retrievable asymmetric flow diverter.

PubMed

Yoganand, Aradhana; Wood, Rachel P; Jimenez, Carlos; Siddiqui, Adnan; Snyder, Kenneth; Nagesh, S V Setlur; Bednarek, D R; Rudin, S; Baier, Robert; Ionita, Ciprian N

2015-02-21

Digital Subtraction Angiography (DSA) is the main diagnostic tool for intracranial aneurysms (IA) flow-diverter (FD) assisted treatment. Based on qualitative contrast flow evaluation, interventionists decide on subsequent steps. We developed a novel fully Retrievable Asymmetric Flow-Diverter (RAFD) which allows controlled deployment, repositioning and detachment achieve optimal flow diversion. The device has a small low porosity or solid region which is placed such that it would achieve maximum aneurysmal in-jet flow deflection with minimum impairment to adjacent vessels. We tested the new RAFD using a flow-loop with an idealized and a patient specific IA phantom in carotid-relevant physiological conditions. We positioned the deflection region at three locations: distally, center and proximally to the aneurysm orifice and analyzed aneurysm dome flow using DSA derived maps for mean transit time (MTT) and bolus arrival times (BAT). Comparison between treated and untreated (control) maps quantified the RAFD positioning effect. Average MTT, related to contrast presence in the aneurysm dome increased, indicating flow decoupling between the aneurysm and parent artery. Maximum effect was observed in the center and proximal position (~75%) of aneurysm models depending on their geometry. BAT maps, correlated well with inflow jet direction and magnitude. Reduction and jet dispersion as high as about 50% was observed for various treatments. We demonstrated the use of DSA data to guide the placement of the RAFD and showed that optimum flow diversion within the aneurysm dome is feasible. This could lead to more effective and a safer IA treatment using FDs.

HDAC Inhibition Blunts Ischemia/Reperfusion Injury by Inducing Cardiomyocyte Autophagy

PubMed Central

Xie, Min; Kong, Yongli; Tan, Wei; May, Herman; Battiprolu, Pavan K.; Pedrozo, Zully; Wang, Zhao; Morales, Cyndi; Luo, Xiang; Cho, Geoffrey; Jiang, Nan; Jessen, Michael E.; Warner, John J.; Lavandero, Sergio; Gillette, Thomas G.; Turer, Aslan T.; Hill, Joseph A.

2014-01-01

Background Reperfusion accounts for a substantial fraction of the myocardial injury occurring with ischemic heart disease. Yet, no standard therapies are available targeting reperfusion injury. Here, we tested the hypothesis that SAHA, a histone deacetylase (HDAC) inhibitor FDA-approved for cancer treatment, will blunt reperfusion injury. Methods and Results Twenty-one rabbits were randomized into 3 groups: a) vehicle control, b) SAHA pretreatment (one day prior and at surgery), and c) SAHA treatment at the time of reperfusion only. Each arm was subjected to ischemia/reperfusion surgery (I/R, 30min coronary ligation, 24h reperfusion). Additionally cultured neonatal and adult rat ventricular cardiomyocytes were subjected to simulated I/R (sI/R) to probe mechanism. SAHA reduced infarct (those reduction inhibitor, SAHA, infarct size in a large animal model, even when delivered in the clinically relevant context of reperfusion. The cardioprotective effects of SAHA during I/R occur, at least in part, through induction of autophagic flux. assayed in both rabbit myocardium and in mice harboring an RFP-GFP-LC3 transgene. In cultured myocytes subjected to sI/R, SAHA pretreatment reduced cell death by 40%. This eduction in cell death correlated with increased autophagic activity in SAHA-treated cells. RNAi-mediated knockdown of ATG7 and ATG5, essential autophagy proteins, abolished SAHA's cardioprotective effects. Conclusions The FDS-approved anti-cancer HDAC inhibitor, SAHA, reduces myocardial infarct size in a large animal model, even when delivered in the clinically relevant context of reperfusion. The cardioprotective effects of SAHA during I/R occur, at least in part, through induction of autophagic flux. PMID:24396039

Angiographic analysis for phantom simulations of endovascular aneurysm treatments with a new fully retrievable asymmetric flow diverter

NASA Astrophysics Data System (ADS)

Yoganand, Aradhana; Wood, Rachel P.; Jimenez, Carlos; Siddiqui, Adnan; Snyder, Kenneth; Setlur Nagesh, S. V.; Bednarek, D. R.; Rudin, S.; Baier, Robert; Ionita, Ciprian N.

2015-03-01

Digital Subtraction Angiography (DSA) is the main diagnostic tool for intracranial aneurysms (IA) flow-diverter (FD) assisted treatment. Based on qualitative contrast flow evaluation, interventionists decide on subsequent steps. We developed a novel fully Retrievable Asymmetric Flow-Diverter (RAFD) which allows controlled deployment, repositioning and detachment achieve optimal flow diversion. The device has a small low porosity or solid region which is placed such that it would achieve maximum aneurysmal in-jet flow deflection with minimum impairment to adjacent vessels. We tested the new RAFD using a flow-loop with an idealized and a patient specific IA phantom in carotid-relevant physiological conditions. We positioned the deflection region at three locations: distally, center and proximally to the aneurysm orifice and analyzed aneurysm dome flow using DSA derived maps for mean transit time (MTT) and bolus arrival times (BAT). Comparison between treated and untreated (control) maps quantified the RAFD positioning effect. Average MTT, related to contrast presence in the aneurysm dome increased, indicating flow decoupling between the aneurysm and parent artery. Maximum effect was observed in the center and proximal position (~75%) of aneurysm models depending on their geometry. BAT maps, correlated well with inflow jet direction and magnitude. Reduction and jet dispersion as high as about 50% was observed for various treatments. We demonstrated the use of DSA data to guide the placement of the RAFD and showed that optimum flow diversion within the aneurysm dome is feasible. This could lead to more effective and a safer IA treatment using FDs.

Comparative Implementation of High Performance Computing for Power System Dynamic Simulations

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

Jin, Shuangshuang; Huang, Zhenyu; Diao, Ruisheng

Dynamic simulation for transient stability assessment is one of the most important, but intensive, computations for power system planning and operation. Present commercial software is mainly designed for sequential computation to run a single simulation, which is very time consuming with a single processer. The application of High Performance Computing (HPC) to dynamic simulations is very promising in accelerating the computing process by parallelizing its kernel algorithms while maintaining the same level of computation accuracy. This paper describes the comparative implementation of four parallel dynamic simulation schemes in two state-of-the-art HPC environments: Message Passing Interface (MPI) and Open Multi-Processing (OpenMP).more » These implementations serve to match the application with dedicated multi-processor computing hardware and maximize the utilization and benefits of HPC during the development process.« less

27ps DFT Molecular Dynamics Simulation of a-maltose: A Reduced Basis Set Study.

USDA-ARS?s Scientific Manuscript database

DFT molecular dynamics simulations are time intensive when carried out on carbohydrates such as alpha-maltose, requiring up to three or more weeks on a fast 16-processor computer to obtain just 5ps of constant energy dynamics. In a recent publication [1] forces for dynamics were generated from B3LY...

An Inviscid Decoupled Method for the Roe FDS Scheme in the Reacting Gas Path of FUN3D

NASA Technical Reports Server (NTRS)

Thompson, Kyle B.; Gnoffo, Peter A.

2016-01-01

An approach is described to decouple the species continuity equations from the mixture continuity, momentum, and total energy equations for the Roe flux difference splitting scheme. This decoupling simplifies the implicit system, so that the flow solver can be made significantly more efficient, with very little penalty on overall scheme robustness. Most importantly, the computational cost of the point implicit relaxation is shown to scale linearly with the number of species for the decoupled system, whereas the fully coupled approach scales quadratically. Also, the decoupled method significantly reduces the cost in wall time and memory in comparison to the fully coupled approach. This work lays the foundation for development of an efficient adjoint solution procedure for high speed reacting flow.

Field Demonstration for P-D-680 Solvent Replacement (Part II)

DTIC Science & Technology

1998-05-12

jo \\ Ji o < s NJ £. ° 8? Q- 3* £?. «" «< o Ö- 8" 03 O C O ~ e O 3 re *i re re w8 g 3 2> 8 = er ^ o 3 ^ fS Ni O...34 3 3. 3. n_ £ 2. O 2- e. re Z. 2 3 v! 3 oso,o,<f)( ji «s S?3re-t930.Q3^. «o.03rt3-3c"o=; 1 » < 3 -•■n O -t33^c«^3ga3 re...soWfirtH T^ skd uiEita, ox^fifk^. 4. KrflTjTS, SAFETY 0? ALTERATIVE F-D-S80 SOLVENT Have you, cr did you have knowledge of ethers

International Space Station (ISS) Node 1 Environmental Control and Life Support (ECLS) System Keep Out Zone On-Orbit Problems

NASA Technical Reports Server (NTRS)

Williams, David E.

2004-01-01

The International Space Station (ISS) Environmental Control and Life Support (ECLS) system performance can be impacted by operations on ISS. This is especially important for the Temperature and Humidity Control (THC) and for the Fire Detection and Suppression (FDS) subsystems. It is also more important for Node 1 since it has become a convenient area for many crew tasks and for stowing hardware prior to Shuttle arrival. This paper will discuss the current requirements for ECLS keep out zones in Node 1; the issues with stowage in Node 1 during Increment 7 and how they impacted the keep out zone requirements; and the solution during Increment 7 and 8 for maintaining the keep out zones in Node 1.

A Novel L-Probe Proximity Fed Patch Antenna With Parasitic Patch and Its Utilization in Antenna Arrays

NASA Astrophysics Data System (ADS)

Sláma, Libor; Dobeš, Josef; Boštík, Tomáš; Vejražka, František

2018-03-01

An analysis of the L-probe fed patch antenna with an extraordinary parasitic patch is described. The element of the antenna is fed by the L-probe partially implemented in PCB. An excellent impedance matching is obtained (< ‑26 dB in the design frequency band 4.4–5 GHz). The radiation characteristics are also very good (gain > 10 dBi). For the numerical analyses, the Full Wave—CST Microwave Studio software was used in both frequency and time domains, and a very good agreement between the Time Domain Solver (TDS) and Frequency Domain Solver (FDS) was obtained. Real antenna samples have been created and measured as well as eight-element antenna arrays designed by the Dolph-Chebyshev method.

Factitious Disorder Presenting with Stuttering in Two Adolescents: The Importance of Psychoeducation.

PubMed

Bolat, Nurullah; Yalçin, Özhan

2017-03-01

A factitious disorder (FD) is a diagnostic entity in which patients intentionally act physically or mentally ill without obvious benefits and without being consciously aware of a clear underlying motive. Most pediatric FD cases have been reported as Munchausen syndrome by Proxy; however, pediatric disease symptoms can also be intentionally falsified by child and adolescent patients. To our knowledge, in the medical literature, an FD patient presenting with stuttering has not been previously reported. In this case report, we aimed to discuss the diagnosis and treatment process of FDs in children and adolescents by reporting the cases of two FD patients presenting with stuttering according to the Diagnostic and Statistical Manual of Mental Disorders-Fifth Edition. Both patients improved with psychoeducation and early confrontation.

Implicit methods for efficient musculoskeletal simulation and optimal control

PubMed Central

van den Bogert, Antonie J.; Blana, Dimitra; Heinrich, Dieter

2011-01-01

The ordinary differential equations for musculoskeletal dynamics are often numerically stiff and highly nonlinear. Consequently, simulations require small time steps, and optimal control problems are slow to solve and have poor convergence. In this paper, we present an implicit formulation of musculoskeletal dynamics, which leads to new numerical methods for simulation and optimal control, with the expectation that we can mitigate some of these problems. A first order Rosenbrock method was developed for solving forward dynamic problems using the implicit formulation. It was used to perform real-time dynamic simulation of a complex shoulder arm system with extreme dynamic stiffness. Simulations had an RMS error of only 0.11 degrees in joint angles when running at real-time speed. For optimal control of musculoskeletal systems, a direct collocation method was developed for implicitly formulated models. The method was applied to predict gait with a prosthetic foot and ankle. Solutions were obtained in well under one hour of computation time and demonstrated how patients may adapt their gait to compensate for limitations of a specific prosthetic limb design. The optimal control method was also applied to a state estimation problem in sports biomechanics, where forces during skiing were estimated from noisy and incomplete kinematic data. Using a full musculoskeletal dynamics model for state estimation had the additional advantage that forward dynamic simulations, could be done with the same implicitly formulated model to simulate injuries and perturbation responses. While these methods are powerful and allow solution of previously intractable problems, there are still considerable numerical challenges, especially related to the convergence of gradient-based solvers. PMID:22102983

OSS: OSSOS Survey Simulator

NASA Astrophysics Data System (ADS)

Petit, J.-M.; Kavelaars, J. J.; Gladman, B.; Alexandersen, M.

2018-05-01

Comparing properties of discovered trans-Neptunian Objects (TNOs) with dynamical models is impossible due to the observational biases that exist in surveys. The OSSOS Survey Simulator takes an intrinsic orbital model (from, for example, the output of a dynamical Kuiper belt emplacement simulation) and applies the survey biases, so the biased simulated objects can be directly compared with real discoveries.

A Simulation Program for Dynamic Infrared (IR) Spectra

ERIC Educational Resources Information Center

Zoerb, Matthew C.; Harris, Charles B.

2013-01-01

A free program for the simulation of dynamic infrared (IR) spectra is presented. The program simulates the spectrum of two exchanging IR peaks based on simple input parameters. Larger systems can be simulated with minor modifications. The program is available as an executable program for PCs or can be run in MATLAB on any operating system. Source…

Exploring travelers' behavior in response to dynamic message signs (DMS) using a driving simulator.

DOT National Transportation Integrated Search

2013-10-01

This research studies the effectiveness of a dynamic message sign (DMS) using a driving : simulator. Over 100 subjects from different socio-economic and age groups were recruited to : drive the simulator under different traffic and driving conditions...

Gamma Ray Observatory (GRO) dynamics simulator requirements and mathematical specifications, revision 1

NASA Technical Reports Server (NTRS)

Harman, R.; Blejer, D.

1990-01-01

The requirements and mathematical specifications for the Gamma Ray Observatory (GRO) Dynamics Simulator are presented. The complete simulator system, which consists of the profie subsystem, simulation control and input/output subsystem, truth model subsystem, onboard computer model subsystem, and postprocessor, is described. The simulator will be used to evaluate and test the attitude determination and control models to be used on board GRO under conditions that simulate the expected in-flight environment.

High Fidelity, “Faster than Real-Time” Simulator for Predicting Power System Dynamic Behavior - Final Technical Report

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

Flueck, Alex

The “High Fidelity, Faster than Real­Time Simulator for Predicting Power System Dynamic Behavior” was designed and developed by Illinois Institute of Technology with critical contributions from Electrocon International, Argonne National Laboratory, Alstom Grid and McCoy Energy. Also essential to the project were our two utility partners: Commonwealth Edison and AltaLink. The project was a success due to several major breakthroughs in the area of large­scale power system dynamics simulation, including (1) a validated faster than real­ time simulation of both stable and unstable transient dynamics in a large­scale positive sequence transmission grid model, (2) a three­phase unbalanced simulation platform formore » modeling new grid devices, such as independently controlled single­phase static var compensators (SVCs), (3) the world’s first high fidelity three­phase unbalanced dynamics and protection simulator based on Electrocon’s CAPE program, and (4) a first­of­its­ kind implementation of a single­phase induction motor model with stall capability. The simulator results will aid power grid operators in their true time of need, when there is a significant risk of cascading outages. The simulator will accelerate performance and enhance accuracy of dynamics simulations, enabling operators to maintain reliability and steer clear of blackouts. In the long­term, the simulator will form the backbone of the newly conceived hybrid real­time protection and control architecture that will coordinate local controls, wide­area measurements, wide­area controls and advanced real­time prediction capabilities. The nation’s citizens will benefit in several ways, including (1) less down time from power outages due to the faster­than­real­time simulator’s predictive capability, (2) higher levels of reliability due to the detailed dynamics plus protection simulation capability, and (3) more resiliency due to the three­ phase unbalanced simulator’s ability to model three­phase and single­ phase networks and devices.« less

Thermalized Drude Oscillators with the LAMMPS Molecular Dynamics Simulator.

PubMed

Dequidt, Alain; Devémy, Julien; Pádua, Agílio A H

2016-01-25

LAMMPS is a very customizable molecular dynamics simulation software, which can be used to simulate a large diversity of systems. We introduce a new package for simulation of polarizable systems with LAMMPS using thermalized Drude oscillators. The implemented functionalities are described and are illustrated by examples. The implementation was validated by comparing simulation results with published data and using a reference software. Computational performance is also analyzed.

Computational Fluid Dynamics Demonstration of Rigid Bodies in Motion

NASA Technical Reports Server (NTRS)

Camarena, Ernesto; Vu, Bruce T.

2011-01-01

The Design Analysis Branch (NE-Ml) at the Kennedy Space Center has not had the ability to accurately couple Rigid Body Dynamics (RBD) and Computational Fluid Dynamics (CFD). OVERFLOW-D is a flow solver that has been developed by NASA to have the capability to analyze and simulate dynamic motions with up to six Degrees of Freedom (6-DOF). Two simulations were prepared over the course of the internship to demonstrate 6DOF motion of rigid bodies under aerodynamic loading. The geometries in the simulations were based on a conceptual Space Launch System (SLS). The first simulation that was prepared and computed was the motion of a Solid Rocket Booster (SRB) as it separates from its core stage. To reduce computational time during the development of the simulation, only half of the physical domain with respect to the symmetry plane was simulated. Then a full solution was prepared and computed. The second simulation was a model of the SLS as it departs from a launch pad under a 20 knot crosswind. This simulation was reduced to Two Dimensions (2D) to reduce both preparation and computation time. By allowing 2-DOF for translations and 1-DOF for rotation, the simulation predicted unrealistic rotation. The simulation was then constrained to only allow translations.

Use of dynamical downscaling to improve the simulation of Central U.S. warm season precipitation in CMIP5 models

NASA Astrophysics Data System (ADS)

Harding, Keith J.; Snyder, Peter K.; Liess, Stefan

2013-11-01

supporting exceptionally productive agricultural lands, the Central U.S. is susceptible to severe droughts and floods. Such precipitation extremes are expected to worsen with climate change. However, future projections are highly uncertain as global climate models (GCMs) generally fail to resolve precipitation extremes. In this study, we assess how well models from the Coupled Model Intercomparison Project Phase 5 (CMIP5) simulate summer means, variability, extremes, and the diurnal cycle of Central U.S. summer rainfall. Output from a subset of historical CMIP5 simulations are used to drive the Weather Research and Forecasting model to determine whether dynamical downscaling improves the representation of Central U.S. rainfall. We investigate which boundary conditions influence dynamically downscaled precipitation estimates and identify GCMs that can reasonably simulate precipitation when downscaled. The CMIP5 models simulate the seasonal mean and variability of summer rainfall reasonably well but fail to resolve extremes, the diurnal cycle, and the dynamic forcing of precipitation. Downscaling to 30 km improves these characteristics of precipitation, with the greatest improvement in the representation of extremes. Additionally, sizeable diurnal cycle improvements occur with higher (10 km) resolution and convective parameterization disabled, as the daily rainfall peak shifts 4 h closer to observations than 30 km resolution simulations. This lends greater confidence that the mechanisms responsible for producing rainfall are better simulated. Because dynamical downscaling can more accurately simulate these aspects of Central U.S. summer rainfall, policymakers can have added confidence in dynamically downscaled rainfall projections, allowing for more targeted adaptation and mitigation.

Molecular Dynamics Simulations to Determine the Structure and Dynamics of Hepatitis B Virus Capsid Bound to a Novel Anti-viral Drug.

PubMed

Watanabe, Go; Sato, Shunsuke; Iwadate, Mitsuo; Umeyama, Hideaki; Hayakawa, Michiyo; Murakami, Yoshiki; Yoneda, Shigetaka

2016-01-01

Hepatitis B virus (HBV) chronically infects millions of people worldwide and is a major cause of serious liver diseases, including liver cirrhosis and liver cancer. In our previous study, in silico screening was used to isolate new anti-viral compounds predicted to bind to the HBV capsid. Four of the isolated compounds have been reported to suppress the cellular multiplication of HBV experimentally. In the present study, molecular dynamics simulations of the HBV capsid were performed under rotational symmetry boundary conditions, to clarify how the structure and dynamics of the capsid are affected at the atomic level by the binding of one of the isolated compounds, C13. Two simulations of the free HBV capsid, two further simulations of the capsid-C13 complex, and one simulation of the capsid-AT-130 complex were performed. For statistical confidence, each set of simulations was repeated by five times, changing the simulation conditions. C13 continued to bind at the predicted binding site during the simulations, supporting the hypothesis that C13 is a capsid-binding compound. The structure and dynamics of the HBV capsid were greatly influenced by the binding and release of C13, and these effects were essentially identical to those seen for AT-130, indicating that C13 likely inhibits the function of the HBV capsid.

Faster protein folding using enhanced conformational sampling of molecular dynamics simulation.

PubMed

Kamberaj, Hiqmet

2018-05-01

In this study, we applied swarm particle-like molecular dynamics (SPMD) approach to enhance conformational sampling of replica exchange simulations. In particular, the approach showed significant improvement in sampling efficiency of conformational phase space when combined with replica exchange method (REM) in computer simulation of peptide/protein folding. First we introduce the augmented dynamical system of equations, and demonstrate the stability of the algorithm. Then, we illustrate the approach by using different fully atomistic and coarse-grained model systems, comparing them with the standard replica exchange method. In addition, we applied SPMD simulation to calculate the time correlation functions of the transitions in a two dimensional surface to demonstrate the enhancement of transition path sampling. Our results showed that folded structure can be obtained in a shorter simulation time using the new method when compared with non-augmented dynamical system. Typically, in less than 0.5 ns using replica exchange runs assuming that native folded structure is known and within simulation time scale of 40 ns in the case of blind structure prediction. Furthermore, the root mean square deviations from the reference structures were less than 2Å. To demonstrate the performance of new method, we also implemented three simulation protocols using CHARMM software. Comparisons are also performed with standard targeted molecular dynamics simulation method. Copyright © 2018 Elsevier Inc. All rights reserved.

SIMULATION OF SUMMER-TIME DIURNAL BACTERIAL DYNAMICS IN THE ATMOSPHERIC SURFACE LAYER

EPA Science Inventory

A model was prepared to simulate the observed concentration dynamics of culturable bacteria in the diurnal summer atmosphere at a Willamette River Valley, Oregon location. The meteorological and bacterial mechanisms included in a dynamic null-dimensional model with one-second tim...

A Direct, Quantitative Connection between Molecular Dynamics Simulations and Vibrational Probe Line Shapes.

PubMed

Xu, Rosalind J; Blasiak, Bartosz; Cho, Minhaeng; Layfield, Joshua P; Londergan, Casey H

2018-05-17

A quantitative connection between molecular dynamics simulations and vibrational spectroscopy of probe-labeled systems would enable direct translation of experimental data into structural and dynamical information. To constitute this connection, all-atom molecular dynamics (MD) simulations were performed for two SCN probe sites (solvent-exposed and buried) in a calmodulin-target peptide complex. Two frequency calculation approaches with substantial nonelectrostatic components, a quantum mechanics/molecular mechanics (QM/MM)-based technique and a solvatochromic fragment potential (SolEFP) approach, were used to simulate the infrared probe line shapes. While QM/MM results disagreed with experiment, SolEFP results matched experimental frequencies and line shapes and revealed the physical and dynamic bases for the observed spectroscopic behavior. The main determinant of the CN probe frequency is the exchange repulsion between the probe and its local structural neighbors, and there is a clear dynamic explanation for the relatively broad probe line shape observed at the "buried" probe site. This methodology should be widely applicable to vibrational probes in many environments.

Potential-based dynamical reweighting for Markov state models of protein dynamics.

PubMed

Weber, Jeffrey K; Pande, Vijay S

2015-06-09

As simulators attempt to replicate the dynamics of large cellular components in silico, problems related to sampling slow, glassy degrees of freedom in molecular systems will be amplified manyfold. It is tempting to augment simulation techniques with external biases to overcome such barriers with ease; biased simulations, however, offer little utility unless equilibrium properties of interest (both kinetic and thermodynamic) can be recovered from the data generated. In this Article, we present a general scheme that harnesses the power of Markov state models (MSMs) to extract equilibrium kinetic properties from molecular dynamics trajectories collected on biased potential energy surfaces. We first validate our reweighting protocol on a simple two-well potential, and we proceed to test our method on potential-biased simulations of the Trp-cage miniprotein. In both cases, we find that equilibrium populations, time scales, and dynamical processes are reliably reproduced as compared to gold standard, unbiased data sets. We go on to discuss the limitations of our dynamical reweighting approach, and we suggest auspicious target systems for further application.

Concerted Dynamic Motions of an FABP4 Model and Its Ligands Revealed by Microsecond Molecular Dynamics Simulations

PubMed Central

2015-01-01

In this work, we investigate the dynamic motions of fatty acid binding protein 4 (FABP4) in the absence and presence of a ligand by explicitly solvated all-atom molecular dynamics simulations. The dynamics of one ligand-free FABP4 and four ligand-bound FABP4s is compared via multiple 1.2 μs simulations. In our simulations, the protein interconverts between the open and closed states. Ligand-free FABP4 prefers the closed state, whereas ligand binding induces a conformational transition to the open state. Coupled with opening and closing of FABP4, the ligand adopts distinct binding modes, which are identified and compared with crystal structures. The concerted dynamics of protein and ligand suggests that there may exist multiple FABP4–ligand binding conformations. Thus, this work provides details about how ligand binding affects the conformational preference of FABP4 and how ligand binding is coupled with a conformational change of FABP4 at an atomic level. PMID:25231537

Concerted dynamic motions of an FABP4 model and its ligands revealed by microsecond molecular dynamics simulations.

PubMed

Li, Yan; Li, Xiang; Dong, Zigang

2014-10-14

In this work, we investigate the dynamic motions of fatty acid binding protein 4 (FABP4) in the absence and presence of a ligand by explicitly solvated all-atom molecular dynamics simulations. The dynamics of one ligand-free FABP4 and four ligand-bound FABP4s is compared via multiple 1.2 μs simulations. In our simulations, the protein interconverts between the open and closed states. Ligand-free FABP4 prefers the closed state, whereas ligand binding induces a conformational transition to the open state. Coupled with opening and closing of FABP4, the ligand adopts distinct binding modes, which are identified and compared with crystal structures. The concerted dynamics of protein and ligand suggests that there may exist multiple FABP4-ligand binding conformations. Thus, this work provides details about how ligand binding affects the conformational preference of FABP4 and how ligand binding is coupled with a conformational change of FABP4 at an atomic level.

Examinations of tRNA Range of Motion Using Simulations of Cryo-EM Microscopy and X-Ray Data.

PubMed

Caulfield, Thomas R; Devkota, Batsal; Rollins, Geoffrey C

2011-01-01

We examined tRNA flexibility using a combination of steered and unbiased molecular dynamics simulations. Using Maxwell's demon algorithm, molecular dynamics was used to steer X-ray structure data toward that from an alternative state obtained from cryogenic-electron microscopy density maps. Thus, we were able to fit X-ray structures of tRNA onto cryogenic-electron microscopy density maps for hybrid states of tRNA. Additionally, we employed both Maxwell's demon molecular dynamics simulations and unbiased simulation methods to identify possible ribosome-tRNA contact areas where the ribosome may discriminate tRNAs during translation. Herein, we collected >500 ns of simulation data to assess the global range of motion for tRNAs. Biased simulations can be used to steer between known conformational stop points, while unbiased simulations allow for a general testing of conformational space previously unexplored. The unbiased molecular dynamics data describes the global conformational changes of tRNA on a sub-microsecond time scale for comparison with steered data. Additionally, the unbiased molecular dynamics data was used to identify putative contacts between tRNA and the ribosome during the accommodation step of translation. We found that the primary contact regions were H71 and H92 of the 50S subunit and ribosomal proteins L14 and L16.

Non-monotonic dynamics of water in its binary mixture with 1,2-dimethoxy ethane: A combined THz spectroscopic and MD simulation study.

PubMed

Das Mahanta, Debasish; Patra, Animesh; Samanta, Nirnay; Luong, Trung Quan; Mukherjee, Biswaroop; Mitra, Rajib Kumar

2016-10-28

A combined experimental (mid- and far-infrared FTIR spectroscopy and THz time domain spectroscopy (TTDS) (0.3-1.6 THz)) and molecular dynamics (MD) simulation technique are used to understand the evolution of the structure and dynamics of water in its binary mixture with 1,2-dimethoxy ethane (DME) over the entire concentration range. The cooperative hydrogen bond dynamics of water obtained from Debye relaxation of TTDS data reveals a non-monotonous behaviour in which the collective dynamics is much faster in the low X w region (where X w is the mole fraction of water in the mixture), whereas in X w ∼ 0.8 region, the dynamics gets slower than that of pure water. The concentration dependence of the reorientation times of water, calculated from the MD simulations, also captures this non-monotonous character. The MD simulation trajectories reveal presence of large amplitude angular jumps, which dominate the orientational relaxation. We rationalize the non-monotonous, concentration dependent orientational dynamics by identifying two different physical mechanisms which operate at high and low water concentration regimes.

A framework for stochastic simulations and visualization of biological electron-transfer dynamics

NASA Astrophysics Data System (ADS)

Nakano, C. Masato; Byun, Hye Suk; Ma, Heng; Wei, Tao; El-Naggar, Mohamed Y.

2015-08-01

Electron transfer (ET) dictates a wide variety of energy-conversion processes in biological systems. Visualizing ET dynamics could provide key insight into understanding and possibly controlling these processes. We present a computational framework named VizBET to visualize biological ET dynamics, using an outer-membrane Mtr-Omc cytochrome complex in Shewanella oneidensis MR-1 as an example. Starting from X-ray crystal structures of the constituent cytochromes, molecular dynamics simulations are combined with homology modeling, protein docking, and binding free energy computations to sample the configuration of the complex as well as the change of the free energy associated with ET. This information, along with quantum-mechanical calculations of the electronic coupling, provides inputs to kinetic Monte Carlo (KMC) simulations of ET dynamics in a network of heme groups within the complex. Visualization of the KMC simulation results has been implemented as a plugin to the Visual Molecular Dynamics (VMD) software. VizBET has been used to reveal the nature of ET dynamics associated with novel nonequilibrium phase transitions in a candidate configuration of the Mtr-Omc complex due to electron-electron interactions.

Temperature for a dynamic spin ensemble

NASA Astrophysics Data System (ADS)

Ma, Pui-Wai; Dudarev, S. L.; Semenov, A. A.; Woo, C. H.

2010-09-01

In molecular dynamics simulations, temperature is evaluated, via the equipartition principle, by computing the mean kinetic energy of atoms. There is no similar recipe yet for evaluating temperature of a dynamic system of interacting spins. By solving semiclassical Langevin spin-dynamics equations, and applying the fluctuation-dissipation theorem, we derive an equation for the temperature of a spin ensemble, expressed in terms of dynamic spin variables. The fact that definitions for the kinetic and spin temperatures are fully consistent is illustrated using large-scale spin dynamics and spin-lattice dynamics simulations.

A fast recursive algorithm for molecular dynamics simulation

NASA Technical Reports Server (NTRS)

Jain, A.; Vaidehi, N.; Rodriguez, G.

1993-01-01

The present recursive algorithm for solving molecular systems' dynamical equations of motion employs internal variable models that reduce such simulations' computation time by an order of magnitude, relative to Cartesian models. Extensive use is made of spatial operator methods recently developed for analysis and simulation of the dynamics of multibody systems. A factor-of-450 speedup over the conventional O(N-cubed) algorithm is demonstrated for the case of a polypeptide molecule with 400 residues.

Molecular Dynamics Simulations of Simple Liquids

ERIC Educational Resources Information Center

Speer, Owner F.; Wengerter, Brian C.; Taylor, Ramona S.

2004-01-01

An experiment, in which students were given the opportunity to perform molecular dynamics simulations on a series of molecular liquids using the Amber suite of programs, is presented. They were introduced to both physical theories underlying classical mechanics simulations and to the atom-atom pair distribution function.

Exploring travelers' behavior in response to dynamic message signs (DMS) using a driving simulator : final report.

DOT National Transportation Integrated Search

2013-10-01

This research studies the effectiveness of a dynamic message sign (DMS) using a driving : simulator. Over 100 subjects from different socio-economic and age groups were recruited to : drive the simulator under different traffic and driving conditions...

Buffer Management Simulation in ATM Networks

NASA Technical Reports Server (NTRS)

Yaprak, E.; Xiao, Y.; Chronopoulos, A.; Chow, E.; Anneberg, L.

1998-01-01

This paper presents a simulation of a new dynamic buffer allocation management scheme in ATM networks. To achieve this objective, an algorithm that detects congestion and updates the dynamic buffer allocation scheme was developed for the OPNET simulation package via the creation of a new ATM module.

MD Simulations of P-Type ATPases in a Lipid Bilayer System.

PubMed

Autzen, Henriette Elisabeth; Musgaard, Maria

2016-01-01

Molecular dynamics (MD) simulation is a computational method which provides insight on protein dynamics with high resolution in both space and time, in contrast to many experimental techniques. MD simulations can be used as a stand-alone method to study P-type ATPases as well as a complementary method aiding experimental studies. In particular, MD simulations have proved valuable in generating and confirming hypotheses relating to the structure and function of P-type ATPases. In the following, we describe a detailed practical procedure on how to set up and run a MD simulation of a P-type ATPase embedded in a lipid bilayer using software free of use for academics. We emphasize general considerations and problems typically encountered when setting up simulations. While full coverage of all possible procedures is beyond the scope of this chapter, we have chosen to illustrate the MD procedure with the Nanoscale Molecular Dynamics (NAMD) and the Visual Molecular Dynamics (VMD) software suites.

Simulation of FRET dyes allows quantitative comparison against experimental data

NASA Astrophysics Data System (ADS)

Reinartz, Ines; Sinner, Claude; Nettels, Daniel; Stucki-Buchli, Brigitte; Stockmar, Florian; Panek, Pawel T.; Jacob, Christoph R.; Nienhaus, Gerd Ulrich; Schuler, Benjamin; Schug, Alexander

2018-03-01

Fully understanding biomolecular function requires detailed insight into the systems' structural dynamics. Powerful experimental techniques such as single molecule Förster Resonance Energy Transfer (FRET) provide access to such dynamic information yet have to be carefully interpreted. Molecular simulations can complement these experiments but typically face limits in accessing slow time scales and large or unstructured systems. Here, we introduce a coarse-grained simulation technique that tackles these challenges. While requiring only few parameters, we maintain full protein flexibility and include all heavy atoms of proteins, linkers, and dyes. We are able to sufficiently reduce computational demands to simulate large or heterogeneous structural dynamics and ensembles on slow time scales found in, e.g., protein folding. The simulations allow for calculating FRET efficiencies which quantitatively agree with experimentally determined values. By providing atomically resolved trajectories, this work supports the planning and microscopic interpretation of experiments. Overall, these results highlight how simulations and experiments can complement each other leading to new insights into biomolecular dynamics and function.

OpenSim: open-source software to create and analyze dynamic simulations of movement.

PubMed

Delp, Scott L; Anderson, Frank C; Arnold, Allison S; Loan, Peter; Habib, Ayman; John, Chand T; Guendelman, Eran; Thelen, Darryl G

2007-11-01

Dynamic simulations of movement allow one to study neuromuscular coordination, analyze athletic performance, and estimate internal loading of the musculoskeletal system. Simulations can also be used to identify the sources of pathological movement and establish a scientific basis for treatment planning. We have developed a freely available, open-source software system (OpenSim) that lets users develop models of musculoskeletal structures and create dynamic simulations of a wide variety of movements. We are using this system to simulate the dynamics of individuals with pathological gait and to explore the biomechanical effects of treatments. OpenSim provides a platform on which the biomechanics community can build a library of simulations that can be exchanged, tested, analyzed, and improved through a multi-institutional collaboration. Developing software that enables a concerted effort from many investigators poses technical and sociological challenges. Meeting those challenges will accelerate the discovery of principles that govern movement control and improve treatments for individuals with movement pathologies.

Two-bead polarizable water models combined with a two-bead multipole force field (TMFF) for coarse-grained simulation of proteins.

PubMed

Li, Min; Zhang, John Z H

2017-03-08

The development of polarizable water models at coarse-grained (CG) levels is of much importance to CG molecular dynamics simulations of large biomolecular systems. In this work, we combined the newly developed two-bead multipole force field (TMFF) for proteins with the two-bead polarizable water models to carry out CG molecular dynamics simulations for benchmark proteins. In our simulations, two different two-bead polarizable water models are employed, the RTPW model representing five water molecules by Riniker et al. and the LTPW model representing four water molecules. The LTPW model is developed in this study based on the Martini three-bead polarizable water model. Our simulation results showed that the combination of TMFF with the LTPW model significantly stabilizes the protein's native structure in CG simulations, while the use of the RTPW model gives better agreement with all-atom simulations in predicting the residue-level fluctuation dynamics. Overall, the TMFF coupled with the two-bead polarizable water models enables one to perform an efficient and reliable CG dynamics study of the structural and functional properties of large biomolecules.

Multiscale modeling of dislocation-precipitate interactions in Fe: From molecular dynamics to discrete dislocations.

PubMed

Lehtinen, Arttu; Granberg, Fredric; Laurson, Lasse; Nordlund, Kai; Alava, Mikko J

2016-01-01

The stress-driven motion of dislocations in crystalline solids, and thus the ensuing plastic deformation process, is greatly influenced by the presence or absence of various pointlike defects such as precipitates or solute atoms. These defects act as obstacles for dislocation motion and hence affect the mechanical properties of the material. Here we combine molecular dynamics studies with three-dimensional discrete dislocation dynamics simulations in order to model the interaction between different kinds of precipitates and a 1/2〈111〉{110} edge dislocation in BCC iron. We have implemented immobile spherical precipitates into the ParaDis discrete dislocation dynamics code, with the dislocations interacting with the precipitates via a Gaussian potential, generating a normal force acting on the dislocation segments. The parameters used in the discrete dislocation dynamics simulations for the precipitate potential, the dislocation mobility, shear modulus, and dislocation core energy are obtained from molecular dynamics simulations. We compare the critical stresses needed to unpin the dislocation from the precipitate in molecular dynamics and discrete dislocation dynamics simulations in order to fit the two methods together and discuss the variety of the relevant pinning and depinning mechanisms.

Recent research and applications of numerical simulation for dynamic response of long-span bridges subjected to multiple loads.

PubMed

Chen, Zhiwei; Chen, Bo

2014-01-01

Many long-span bridges have been built throughout the world in recent years but they are often subject to multiple types of dynamic loads, especially those located in wind-prone regions and carrying both trains and road vehicles. To ensure the safety and functionality of these bridges, dynamic responses of long-span bridges are often required for bridge assessment. Given that there are several limitations for the assessment based on field measurement of dynamic responses, a promising approach is based on numerical simulation technologies. This paper provides a detailed review of key issues involved in dynamic response analysis of long-span multiload bridges based on numerical simulation technologies, including dynamic interactions between running trains and bridge, between running road vehicles and bridge, and between wind and bridge, and in the wind-vehicle-bridge coupled system. Then a comprehensive review is conducted for engineering applications of newly developed numerical simulation technologies to safety assessment of long-span bridges, such as assessment of fatigue damage and assessment under extreme events. Finally, the existing problems and promising research efforts for the numerical simulation technologies and their applications to assessment of long-span multiload bridges are explored.

Recent Research and Applications of Numerical Simulation for Dynamic Response of Long-Span Bridges Subjected to Multiple Loads

PubMed Central

Chen, Zhiwei; Chen, Bo

2014-01-01

Many long-span bridges have been built throughout the world in recent years but they are often subject to multiple types of dynamic loads, especially those located in wind-prone regions and carrying both trains and road vehicles. To ensure the safety and functionality of these bridges, dynamic responses of long-span bridges are often required for bridge assessment. Given that there are several limitations for the assessment based on field measurement of dynamic responses, a promising approach is based on numerical simulation technologies. This paper provides a detailed review of key issues involved in dynamic response analysis of long-span multiload bridges based on numerical simulation technologies, including dynamic interactions between running trains and bridge, between running road vehicles and bridge, and between wind and bridge, and in the wind-vehicle-bridge coupled system. Then a comprehensive review is conducted for engineering applications of newly developed numerical simulation technologies to safety assessment of long-span bridges, such as assessment of fatigue damage and assessment under extreme events. Finally, the existing problems and promising research efforts for the numerical simulation technologies and their applications to assessment of long-span multiload bridges are explored. PMID:25006597

Dynamic Biological Functioning Important for Simulating and Stabilizing Ocean Biogeochemistry

NASA Astrophysics Data System (ADS)

Buchanan, P. J.; Matear, R. J.; Chase, Z.; Phipps, S. J.; Bindoff, N. L.

2018-04-01

The biogeochemistry of the ocean exerts a strong influence on the climate by modulating atmospheric greenhouse gases. In turn, ocean biogeochemistry depends on numerous physical and biological processes that change over space and time. Accurately simulating these processes is fundamental for accurately simulating the ocean's role within the climate. However, our simulation of these processes is often simplistic, despite a growing understanding of underlying biological dynamics. Here we explore how new parameterizations of biological processes affect simulated biogeochemical properties in a global ocean model. We combine 6 different physical realizations with 6 different biogeochemical parameterizations (36 unique ocean states). The biogeochemical parameterizations, all previously published, aim to more accurately represent the response of ocean biology to changing physical conditions. We make three major findings. First, oxygen, carbon, alkalinity, and phosphate fields are more sensitive to changes in the ocean's physical state. Only nitrate is more sensitive to changes in biological processes, and we suggest that assessment protocols for ocean biogeochemical models formally include the marine nitrogen cycle to assess their performance. Second, we show that dynamic variations in the production, remineralization, and stoichiometry of organic matter in response to changing environmental conditions benefit the simulation of ocean biogeochemistry. Third, dynamic biological functioning reduces the sensitivity of biogeochemical properties to physical change. Carbon and nitrogen inventories were 50% and 20% less sensitive to physical changes, respectively, in simulations that incorporated dynamic biological functioning. These results highlight the importance of a dynamic biology for ocean properties and climate.

Application of principal component analysis in protein unfolding: an all-atom molecular dynamics simulation study.

PubMed

Das, Atanu; Mukhopadhyay, Chaitali

2007-10-28

We have performed molecular dynamics (MD) simulation of the thermal denaturation of one protein and one peptide-ubiquitin and melittin. To identify the correlation in dynamics among various secondary structural fragments and also the individual contribution of different residues towards thermal unfolding, principal component analysis method was applied in order to give a new insight to protein dynamics by analyzing the contribution of coefficients of principal components. The cross-correlation matrix obtained from MD simulation trajectory provided important information regarding the anisotropy of backbone dynamics that leads to unfolding. Unfolding of ubiquitin was found to be a three-state process, while that of melittin, though smaller and mostly helical, is more complicated.

Application of principal component analysis in protein unfolding: An all-atom molecular dynamics simulation study

NASA Astrophysics Data System (ADS)

Das, Atanu; Mukhopadhyay, Chaitali

2007-10-01

We have performed molecular dynamics (MD) simulation of the thermal denaturation of one protein and one peptide—ubiquitin and melittin. To identify the correlation in dynamics among various secondary structural fragments and also the individual contribution of different residues towards thermal unfolding, principal component analysis method was applied in order to give a new insight to protein dynamics by analyzing the contribution of coefficients of principal components. The cross-correlation matrix obtained from MD simulation trajectory provided important information regarding the anisotropy of backbone dynamics that leads to unfolding. Unfolding of ubiquitin was found to be a three-state process, while that of melittin, though smaller and mostly helical, is more complicated.

Probing antibody internal dynamics with fluorescence anisotropy and molecular dynamics simulations.

PubMed

Kortkhonjia, Ekaterine; Brandman, Relly; Zhou, Joe Zhongxiang; Voelz, Vincent A; Chorny, Ilya; Kabakoff, Bruce; Patapoff, Thomas W; Dill, Ken A; Swartz, Trevor E

2013-01-01

The solution dynamics of antibodies are critical to antibody function. We explore the internal solution dynamics of antibody molecules through the combination of time-resolved fluorescence anisotropy experiments on IgG1 with more than two microseconds of all-atom molecular dynamics (MD) simulations in explicit water, an order of magnitude more than in previous simulations. We analyze the correlated motions with a mutual information entropy quantity, and examine state transition rates in a Markov-state model, to give coarse-grained descriptors of the motions. Our MD simulations show that while there are many strongly correlated motions, antibodies are highly flexible, with F(ab) and F(c) domains constantly forming and breaking contacts, both polar and non-polar. We find that salt bridges break and reform, and not always with the same partners. While the MD simulations in explicit water give the right time scales for the motions, the simulated motions are about 3-fold faster than the experiments. Overall, the picture that emerges is that antibodies do not simply fluctuate around a single state of atomic contacts. Rather, in these large molecules, different atoms come in contact during different motions.

OSSOS: X. How to use a Survey Simulator: Statistical Testing of Dynamical Models Against the Real Kuiper Belt

NASA Astrophysics Data System (ADS)

Lawler, Samantha M.; Kavelaars, J. J.; Alexandersen, Mike; Bannister, Michele T.; Gladman, Brett; Petit, Jean-Marc; Shankman, Cory

2018-05-01

All surveys include observational biases, which makes it impossible to directly compare properties of discovered trans-Neptunian Objects (TNOs) with dynamical models. However, by carefully keeping track of survey pointings on the sky, detection limits, tracking fractions, and rate cuts, the biases from a survey can be modelled in Survey Simulator software. A Survey Simulator takes an intrinsic orbital model (from, for example, the output of a dynamical Kuiper belt emplacement simulation) and applies the survey biases, so that the biased simulated objects can be directly compared with real discoveries. This methodology has been used with great success in the Outer Solar System Origins Survey (OSSOS) and its predecessor surveys. In this chapter, we give four examples of ways to use the OSSOS Survey Simulator to gain knowledge about the true structure of the Kuiper Belt. We demonstrate how to statistically compare different dynamical model outputs with real TNO discoveries, how to quantify detection biases within a TNO population, how to measure intrinsic population sizes, and how to use upper limits from non-detections. We hope this will provide a framework for dynamical modellers to statistically test the validity of their models.

Nonlinear dynamic simulation of single- and multi-spool core engines

NASA Technical Reports Server (NTRS)

Schobeiri, T.; Lippke, C.; Abouelkheir, M.

1993-01-01

In this paper a new computational method for accurate simulation of the nonlinear dynamic behavior of single- and multi-spool core engines, turbofan engines, and power generation gas turbine engines is presented. In order to perform the simulation, a modularly structured computer code has been developed which includes individual mathematical modules representing various engine components. The generic structure of the code enables the dynamic simulation of arbitrary engine configurations ranging from single-spool thrust generation to multi-spool thrust/power generation engines under adverse dynamic operating conditions. For precise simulation of turbine and compressor components, row-by-row calculation procedures were implemented that account for the specific turbine and compressor cascade and blade geometry and characteristics. The dynamic behavior of the subject engine is calculated by solving a number of systems of partial differential equations, which describe the unsteady behavior of the individual components. In order to ensure the capability, accuracy, robustness, and reliability of the code, comprehensive critical performance assessment and validation tests were performed. As representatives, three different transient cases with single- and multi-spool thrust and power generation engines were simulated. The transient cases range from operating with a prescribed fuel schedule, to extreme load changes, to generator and turbine shut down.

Melt-growth dynamics in CdTe crystals

DOE PAGES

Zhou, X. W.; Ward, D. K.; Wong, B. M.; ...

2012-06-01

We use a new, quantum-mechanics-based bond-order potential (BOP) to reveal melt growth dynamics and fine scale defect formation mechanisms in CdTe crystals. Previous molecular dynamics simulations of semiconductors have shown qualitatively incorrect behavior due to the lack of an interatomic potential capable of predicting both crystalline growth and property trends of many transitional structures encountered during the melt → crystal transformation. Here, we demonstrate successful molecular dynamics simulations of melt growth in CdTe using a BOP that significantly improves over other potentials on property trends of different phases. Our simulations result in a detailed understanding of defect formation during themore » melt growth process. Equally important, we show that the new BOP enables defect formation mechanisms to be studied at a scale level comparable to empirical molecular dynamics simulation methods with a fidelity level approaching quantum-mechanical methods.« less

Dynamic modelling of an adsorption storage tank using a hybrid approach combining computational fluid dynamics and process simulation

USGS Publications Warehouse

Mota, J.P.B.; Esteves, I.A.A.C.; Rostam-Abadi, M.

2004-01-01

A computational fluid dynamics (CFD) software package has been coupled with the dynamic process simulator of an adsorption storage tank for methane fuelled vehicles. The two solvers run as independent processes and handle non-overlapping portions of the computational domain. The codes exchange data on the boundary interface of the two domains to ensure continuity of the solution and of its gradient. A software interface was developed to dynamically suspend and activate each process as necessary, and be responsible for data exchange and process synchronization. This hybrid computational tool has been successfully employed to accurately simulate the discharge of a new tank design and evaluate its performance. The case study presented here shows that CFD and process simulation are highly complementary computational tools, and that there are clear benefits to be gained from a close integration of the two. ?? 2004 Elsevier Ltd. All rights reserved.

ls1 mardyn: The Massively Parallel Molecular Dynamics Code for Large Systems.

PubMed

Niethammer, Christoph; Becker, Stefan; Bernreuther, Martin; Buchholz, Martin; Eckhardt, Wolfgang; Heinecke, Alexander; Werth, Stephan; Bungartz, Hans-Joachim; Glass, Colin W; Hasse, Hans; Vrabec, Jadran; Horsch, Martin

2014-10-14

The molecular dynamics simulation code ls1 mardyn is presented. It is a highly scalable code, optimized for massively parallel execution on supercomputing architectures and currently holds the world record for the largest molecular simulation with over four trillion particles. It enables the application of pair potentials to length and time scales that were previously out of scope for molecular dynamics simulation. With an efficient dynamic load balancing scheme, it delivers high scalability even for challenging heterogeneous configurations. Presently, multicenter rigid potential models based on Lennard-Jones sites, point charges, and higher-order polarities are supported. Due to its modular design, ls1 mardyn can be extended to new physical models, methods, and algorithms, allowing future users to tailor it to suit their respective needs. Possible applications include scenarios with complex geometries, such as fluids at interfaces, as well as nonequilibrium molecular dynamics simulation of heat and mass transfer.

Stochastic modeling and simulation of reaction-diffusion system with Hill function dynamics.

PubMed

Chen, Minghan; Li, Fei; Wang, Shuo; Cao, Young

2017-03-14

Stochastic simulation of reaction-diffusion systems presents great challenges for spatiotemporal biological modeling and simulation. One widely used framework for stochastic simulation of reaction-diffusion systems is reaction diffusion master equation (RDME). Previous studies have discovered that for the RDME, when discretization size approaches zero, reaction time for bimolecular reactions in high dimensional domains tends to infinity. In this paper, we demonstrate that in the 1D domain, highly nonlinear reaction dynamics given by Hill function may also have dramatic change when discretization size is smaller than a critical value. Moreover, we discuss methods to avoid this problem: smoothing over space, fixed length smoothing over space and a hybrid method. Our analysis reveals that the switch-like Hill dynamics reduces to a linear function of discretization size when the discretization size is small enough. The three proposed methods could correctly (under certain precision) simulate Hill function dynamics in the microscopic RDME system.

Distributed dynamic simulations of networked control and building performance applications.

PubMed

Yahiaoui, Azzedine

2018-02-01

The use of computer-based automation and control systems for smart sustainable buildings, often so-called Automated Buildings (ABs), has become an effective way to automatically control, optimize, and supervise a wide range of building performance applications over a network while achieving the minimum energy consumption possible, and in doing so generally refers to Building Automation and Control Systems (BACS) architecture. Instead of costly and time-consuming experiments, this paper focuses on using distributed dynamic simulations to analyze the real-time performance of network-based building control systems in ABs and improve the functions of the BACS technology. The paper also presents the development and design of a distributed dynamic simulation environment with the capability of representing the BACS architecture in simulation by run-time coupling two or more different software tools over a network. The application and capability of this new dynamic simulation environment are demonstrated by an experimental design in this paper.

Fragmentation-based QM/MM simulations: length dependence of chain dynamics and hydrogen bonding of polyethylene oxide and polyethylene in aqueous solutions.

PubMed

Li, Hui; Li, Wei; Li, Shuhua; Ma, Jing

2008-06-12

Molecular fragmentation quantum mechanics (QM) calculations have been combined with molecular mechanics (MM) to construct the fragmentation QM/MM method for simulations of dilute solutions of macromolecules. We adopt the electrostatics embedding QM/MM model, where the low-cost generalized energy-based fragmentation calculations are employed for the QM part. Conformation energy calculations, geometry optimizations, and Born-Oppenheimer molecular dynamics simulations of poly(ethylene oxide), PEO(n) (n = 6-20), and polyethylene, PE(n) ( n = 9-30), in aqueous solution have been performed within the framework of both fragmentation and conventional QM/MM methods. The intermolecular hydrogen bonding and chain configurations obtained from the fragmentation QM/MM simulations are consistent with the conventional QM/MM method. The length dependence of chain conformations and dynamics of PEO and PE oligomers in aqueous solutions is also investigated through the fragmentation QM/MM molecular dynamics simulations.

Distributed dynamic simulations of networked control and building performance applications

PubMed Central

Yahiaoui, Azzedine

2017-01-01

The use of computer-based automation and control systems for smart sustainable buildings, often so-called Automated Buildings (ABs), has become an effective way to automatically control, optimize, and supervise a wide range of building performance applications over a network while achieving the minimum energy consumption possible, and in doing so generally refers to Building Automation and Control Systems (BACS) architecture. Instead of costly and time-consuming experiments, this paper focuses on using distributed dynamic simulations to analyze the real-time performance of network-based building control systems in ABs and improve the functions of the BACS technology. The paper also presents the development and design of a distributed dynamic simulation environment with the capability of representing the BACS architecture in simulation by run-time coupling two or more different software tools over a network. The application and capability of this new dynamic simulation environment are demonstrated by an experimental design in this paper. PMID:29568135