Metal-oxide-metal point contact junction detectors. [detection mechanism and mechanical stability

NASA Technical Reports Server (NTRS)

Baird, J.; Havemann, R. H.; Fults, R. D.

1973-01-01

The detection mechanism(s) and design of a mechanically stable metal-oxide-metal point contact junction detector are considered. A prototype for a mechanically stable device has been constructed and tested. A technique has been developed which accurately predicts microwave video detector and heterodyne mixer SIM (semiconductor-insulator-metal) diode performance from low dc frequency volt-ampere curves. The difference in contact potential between the two metals and geometrically induced rectification constitute the detection mechanisms.

Metal Detectors and Feeling Safe at School

ERIC Educational Resources Information Center

Gastic, Billie

2011-01-01

This article argues that metal detectors bestow an organizational stigma to schools. One symptom of this is students' heightened level of fear at school. Using data from the National Longitudinal Study of Adolescent Health (Add Health) and a matched-pair design, this study finds that metal detectors are negatively correlated with students' sense…

Metal Detectors in the Public Schools: Fourth Amendment Concerns.

ERIC Educational Resources Information Center

Ferraraccio, Michael

1999-01-01

Asks whether proponents' justifications for using metal detectors to counteract school violence are compelling enough to override students' privacy interests. Concludes that there are serious constitutional concerns raised by using metal detectors. The rationale for upholding school searches in other contexts does not apply to metal-detector…

The utility of handheld metal detector in confirming metallic foreign body ingestion in the pediatric emergency department.

PubMed

Saz, Eylem Ulaş; Arikan, Ciğdem; Ozgenç, Funda; Duyu, Muhterem; Ozananar, Yeliz

2010-06-01

We aimed to identify the presence of ingested metallic foreign bodies with handheld metal detector in the pediatric population. All children (n=40) known or suspected to have ingested a MFB and who presented to the Emergency Department of the Children's Hospital of Ege University were prospectively ascertained. All patients underwent both radiographic evaluation and handheld metal detector scanning of the chest and abdomen on their presentation. In the present prospective study, we compared handheld metal detector scanning with plain radiography. The end point of the study compared metallic foreign body findings with handheld metal detector vs radiological findings during an eight-month period. Forty subjects with possible metallic foreign body ingestion were enrolled into the study. The principle investigator scanned all subjects. Disease was defined by the presence of a foreign body in the gastrointestinal tract on radiograph. Radiographically, 35 foreign bodies were found, and handheld metal detector revealed 31 of them. The sensitivity of handheld metal detector was 88.6% (95% confidence interval [CI]: 72.1%-96.5%), specificity 100% (95% CI: 61.8%-100%), positive predictive value (PPV) 100% (95% CI: 85.8%-100%), and negative predictive value 55.5% (95% CI: 34.3%-84.6%). Handheld metal detector revealed that 2 metallic foreign bodies (1 pushpin, 1 coin) were localized to the chest, which was confirmed by radiography, and urgent removal was performed with endoscopy. Handheld metal detector scanning is an accurate, inexpensive, radiation-free screening tool and should be used for evaluation of patients suspected of ingesting metallic foreign bodies.

A new kind of metal detector based on chaotic oscillator

NASA Astrophysics Data System (ADS)

Hu, Wenjing

2017-12-01

The sensitivity of a metal detector greatly depends on the identification ability to weak signals from the probe. In order to improve the sensitivity of metal detectors, this paper applies the Duffing chaotic oscillator to metal detectors based on its characteristic which is very sensitive to weak periodic signals. To make a suitable Duffing system for detectors, this paper computes two Lyapunov characteristics exponents of the Duffing oscillator, which help to obtain the threshold of the Duffing system in the critical state accurately and give quantitative criteria for chaos. Meanwhile, a corresponding simulation model of the chaotic oscillator is made by the Simulink tool box of Matlab. Simulation results shows that Duffing oscillator is very sensitive to sinusoidal signals in high frequency cases. And experimental results show that the measurable diameter of metal particles is about 1.5mm. It indicates that this new method can feasibly and effectively improve the metal detector sensitivity.

Metal detectors: security vs. customer service.

PubMed

Rhimi, Mustapha B

2010-01-01

The pros and cons of metal detectors in hospitals should be reviewed again, the author recommends, in light of new conditions that are making emergency departments even more violent and volatile. In this article, he reports on the results of three years employment of metal detection.

How might we increase physical activity through dog walking?: A comprehensive review of dog walking correlates.

PubMed

Westgarth, Carri; Christley, Robert M; Christian, Hayley E

2014-08-20

Physical inactivity and sedentary behaviour are major threats to population health. A considerable proportion of people own dogs, and there is good evidence that dog ownership is associated with higher levels of physical activity. However not all owners walk their dogs regularly. This paper comprehensively reviews the evidence for correlates of dog walking so that effective interventions may be designed to increase the physical activity of dog owners. Published findings from 1990-2012 in both the human and veterinary literature were collated and reviewed for evidence of factors associated with objective and self-reported measures of dog walking behaviour, or reported perceptions about dog walking. Study designs included cross-sectional observational, trials and qualitative interviews. There is good evidence that the strength of the dog-owner relationship, through a sense of obligation to walk the dog, and the perceived support and motivation a dog provides for walking, is strongly associated with increased walking. The perceived exercise requirements of the dog may also be a modifiable point for intervention. In addition, access to suitable walking areas with dog supportive features that fulfil dog needs such as off-leash exercise, and that also encourage human social interaction, may be incentivising. Current evidence suggests that dog walking may be most effectively encouraged through targeting the dog-owner relationship and by providing dog-supportive physical environments. More research is required to investigate the influence of individual owner and dog factors on 'intention' to walk the dog as well as the influence of human social interaction whilst walking a dog. The effects of policy and cultural practices relating to dog ownership and walking should also be investigated. Future studies must be of a higher quality methodological design, including accounting for the effects of confounding between variables, and longitudinal designs and testing of

Stacked Metal Silicide/Silicon Far-Infrared Detectors

NASA Technical Reports Server (NTRS)

Maserjian, Joseph

1988-01-01

Selective doping of silicon in proposed metal silicide/silicon Schottky-barrier infrared photodetector increases maximum detectable wavelength. Stacking layers to form multiple Schottky barriers increases quantum efficiency of detector. Detectors of new type enhance capabilities of far-infrared imaging arrays. Grows by molecular-beam epitaxy on silicon waferscontaining very-large-scale integrated circuits. Imaging arrays of detectors made in monolithic units with image-preprocessing circuitry.

Controlled research utilizing a basic all-metal detector in the search for buried firearms and miscellaneous weapons.

PubMed

Rezos, Mary M; Schultz, John J; Murdock, Ronald A; Smith, Stephen A

2010-02-25

Incorporating geophysical technologies into forensic investigations has become a growing practice. Oftentimes, forensic professionals rely on basic metal detectors to assist their efforts during metallic weapons searches. This has created a need for controlled research in the area of weapons searches, specifically to formulate guidelines for geophysical methods that may be appropriate for locating weapons that have been discarded or buried by criminals attempting to conceal their involvement in a crime. Controlled research allows not only for testing of geophysical equipment, but also for updating search methodologies. This research project was designed to demonstrate the utility of an all-metal detector for locating a buried metallic weapon through detecting and identifying specific types of buried metal targets. Controlled testing of 32 buried targets which represented a variety of sizes and metallic compositions included 16 decommissioned street-level firearms, 6 pieces of assorted scrap metals, and 10 blunt or bladed weapons. While all forensic targets included in the project were detected with the basic all-metal detector, the size of the weapon and surface area were the two variables that affected maximum depth of detection, particularly with the firearm sample. For example, when using a High setting the largest firearms were detected at a maximum depth of 55 cm, but the majority of the remaining targets were only detected at a maximum depth of 40 cm or less. Overall, the all-metal detector proved to be a very good general purpose metal detector best suited for detecting metallic items at shallow depths. 2009 Elsevier Ireland Ltd. All rights reserved.

Development of a polymer based fiberoptic magnetostrictive metal detector system.

PubMed

Hua, Wei Shu; Hooks, Joshua Rosenberg; Wu, Wen Jong; Wang, Wei Chih

2010-10-01

This paper presents a new metal detector using a fiberoptic magnetostriction sensor. The metal sensor uses a fiber-optic Mach-Zehnder interferometer with a newly developed ferromagnetic polymer as the magnetostrictive sensing material. This polymeric magnetostrictive fiberoptic metal sensor is simple to fabricate, small in size, and resistant to RF interference (which is common in typical electromagnetic type metal detectors). Metal detection is based on disruption of the magnetic flux density across the magnetostriction sensor. In this paper, characteristics of the material being sensed and magnetic properties of the ferromagnetic polymers will be discussed.

Mentally walking through doorways causes forgetting: The location updating effect and imagination.

PubMed

Lawrence, Zachary; Peterson, Daniel

2016-01-01

Researchers have documented an intriguing phenomenon whereby simply walking through a doorway causes forgetting (the location updating effect). The Event Horizon Model is the most commonly cited theory to explain these data. Importantly, this model explains the effect without invoking the importance or reliance upon perceptual information (i.e., seeing oneself pass through the doorway). This generates the intriguing hypothesis that the effect may be demonstrated in participants who simply imagine walking through a doorway. Across two experiments, we explicitly test this hypothesis. Participants familiarised themselves with both real (Experiment 1) and virtual (Experiment 2) environments which served as the setting for their mental walk. They were then provided with an image to remember and were instructed to imagine themselves walking through the previously presented space. In both experiments, when the mental walk required participants to pass through a doorway, more forgetting occurred, consistent with the predictions laid out in the Event Horizon Model.

Photocapacitive MIS infrared detectors

NASA Technical Reports Server (NTRS)

Sher, A.; Lu, S. S.-M.; Moriarty, J. A.; Crouch, R. K.; Miller, W. E.

1978-01-01

A new class of room-temperature infrared detectors has been developed through use of metal-insulator-semiconductor (MIS) or metal-insulator-semiconductor-insulator-metal (MISIM) slabs. The detectors, which have been fabricated from Si, Ge and GaAs, rely for operation on the electrical capacitance variations induced by modulated incident radiation. The peak detectivity for a 1000-A Si MISIM detector is comparable to that of a conventional Si detector functioning in the photovoltaic mode. Optimization of the photocapacitive-mode detection sensitivity is discussed.

Walkings-Through Paint: A C/A/R/Tography of Slow Scholarship

ERIC Educational Resources Information Center

Lasczik Cutcher, Alexandra; Irwin, Rita L.

2017-01-01

This visual essay portrays a walkings-through of experience, journeys, and engagements positioned as a c/a/r/tography. The assemblage of this c/a/r/tography draws upon Deleuzoguattarian notions of affect and the carte, the methodology of a/r/tography, and contemporary art and research ambulatory practices. The walkings-through are staged in the…

Evaluation of a metal artifacts reduction algorithm applied to postinterventional flat panel detector CT imaging.

PubMed

Stidd, D A; Theessen, H; Deng, Y; Li, Y; Scholz, B; Rohkohl, C; Jhaveri, M D; Moftakhar, R; Chen, M; Lopes, D K

2014-01-01

Flat panel detector CT images are degraded by streak artifacts caused by radiodense implanted materials such as coils or clips. A new metal artifacts reduction prototype algorithm has been used to minimize these artifacts. The application of this new metal artifacts reduction algorithm was evaluated for flat panel detector CT imaging performed in a routine clinical setting. Flat panel detector CT images were obtained from 59 patients immediately following cerebral endovascular procedures or as surveillance imaging for cerebral endovascular or surgical procedures previously performed. The images were independently evaluated by 7 physicians for metal artifacts reduction on a 3-point scale at 2 locations: immediately adjacent to the metallic implant and 3 cm away from it. The number of visible vessels before and after metal artifacts reduction correction was also evaluated within a 3-cm radius around the metallic implant. The metal artifacts reduction algorithm was applied to the 59 flat panel detector CT datasets without complications. The metal artifacts in the reduction-corrected flat panel detector CT images were significantly reduced in the area immediately adjacent to the implanted metal object (P = .05) and in the area 3 cm away from the metal object (P = .03). The average number of visible vessel segments increased from 4.07 to 5.29 (P = .1235) after application of the metal artifacts reduction algorithm to the flat panel detector CT images. Metal artifacts reduction is an effective method to improve flat panel detector CT images degraded by metal artifacts. Metal artifacts are significantly decreased by the metal artifacts reduction algorithm, and there was a trend toward increased vessel-segment visualization. © 2014 by American Journal of Neuroradiology.

2D metal profile detector using a polymeric fiber optic sensor

NASA Astrophysics Data System (ADS)

Hua, Wei-Shu; Hooks, Joshua R.; Erwin, Nicholas A.; Wu, Wen-Jong; Wang, Wei-Chih

2012-04-01

As sensors become integrated in more applications, interest in magnetostrictive sensor technology has blossomed. Magnetostrictive materials have many advantages and useful applications in daily life, such as high efficient coupling between elastic and polymer material, large displacement, magnetic field sensors, micro actuator and motion motor, etc. The purpose of this paper is to develop a metal sensor which is capable of detecting different geometries and shapes of metal objects. The main configuration is using a Mach-Zehnder fiber-optic interferometer coated with magnetostrictive material. The metal detector system is a novel design of metal detector, easy to fabricate and capable of high sensitivity. In our design, metal detection is made possible by disrupting the magnetic flux density that encompasses the magnetostriction sensor. In this paper, experimental setups are described and metal sensing results are presented. The results of detecting complex metal's geometry and metal's mapping results are discussed.

Airport metal detector activation is rare after posterior spinal fusion in children with scoliosis.

PubMed

Fabricant, Peter D; Robles, Alex; Blanco, John S

2013-12-01

Since the September 11, 2001 terrorist attacks on the World Trade Center in New York City, travel security has become an ever-increasing priority in the United States. Frequent parent and patient inquiry and recent literature reports have generated interest in the impact of heightened security measures on patients with orthopaedic implants, and have indicated increasing rates of metal detector triggering. There are no reports to date, however, evaluating children and adolescents who have undergone posterior spinal fusion for scoliosis, so responses to patient and parent inquiries are not data-driven. The purpose of this study is to determine the frequency of airport metal detector triggering by patients who have had posterior-only spinal fusion and to characterise any potential predictors of metal detector activation. A cross-sectional study was performed by interviewing 90 patients who underwent posterior-only spinal fusion for a diagnosis of juvenile or adolescent idiopathic scoliosis and have travelled by air in the past year. Demographic, clinical and surgical instrumentation data were collected and evaluated, along with patients' reports of airport metal detector triggering and subsequent screening procedures. Five patients with stainless steel instrumentation (5.6 % of the cohort) triggered an airport walkthrough metal detector, and an additional five patients who did not trigger an airport detector triggered a handheld detector at a different venue. All patients who triggered an airport metal detector had stainless steel instrumentation implanted prior to 2008, and no patient with titanium instrumentation triggered any detector in any venue. All trigger events required subsequent screening procedures, even when an implant card was presented. In this cohort of children and adolescents with posterior spinal instrumentation, airport walkthrough metal detector triggering was a rare event. Therefore, we advise patients and families with planned posterior

Disproportionality in Daily Metal Detector Student Searches in U.S. Public Schools

ERIC Educational Resources Information Center

Gastic, Billie; Johnson, Dominique

2015-01-01

While the effectiveness of metal detectors to improve school safety remains debated, many public schools continue to rely on this technology to control school violence. Among them is the 1% of public schools where students are searched on a daily basis by metal detector. This study examines the school-level risk factors associated with daily…

USB 3.0 readout and time-walk correction method for Timepix3 detector

NASA Astrophysics Data System (ADS)

Turecek, D.; Jakubek, J.; Soukup, P.

2016-12-01

The hybrid particle counting pixel detectors of Medipix family are well known. In this contribution we present new USB 3.0 based interface AdvaDAQ for Timepix3 detector. The AdvaDAQ interface is designed with a maximal emphasis to the flexibility. It is successor of FitPIX interface developed in IEAP CTU in Prague. Its modular architecture supports all Medipix/Timepix chips and all their different readout modes: Medipix2, Timepix (serial and parallel), Medipix3 and Timepix3. The high bandwidth of USB 3.0 permits readout of 1700 full frames per second with Timepix or 8 channel data acquisition from Timepix3 at frequency of 320 MHz. The control and data acquisition is integrated in a multiplatform PiXet software (MS Windows, Mac OS, Linux). In the second part of the publication a new method for correction of the time-walk effect in Timepix3 is described. Moreover, a fully spectroscopic X-ray imaging with Timepix3 detector operated in the ToT mode (Time-over-Threshold) is presented. It is shown that the AdvaDAQ's readout speed is sufficient to perform spectroscopic measurement at full intensity of radiographic setups equipped with nano- or micro-focus X-ray tubes.

The Role of the Principal Walk-Through

ERIC Educational Resources Information Center

Holgersen, Karen Lee

2017-01-01

The purpose of this qualitative case study was to describe the principal's perspective of the efficacy of the principal walk-through as a tool to improve and gather formative feedback about teaching. Principals from selected schools in one district were interviewed to further clarify their feelings and provide insight into how they engaged in the…

Moving belt metal detector

NASA Astrophysics Data System (ADS)

Nelson, Carl V.; Mendat, Deborah P.; Huynh, Toan B.

2006-05-01

The Johns Hopkins University Applied Physics Laboratory (APL) has developed a prototype metal detection survey system that will increase the search speed of conventional technology while maintaining high sensitivity. Higher search speeds will reduce the time to clear roads of landmines and improvised explosive devices (IED) and to locate unexploded ordnance (UXO) at Base Realignment and Closure (BRAC) sites, thus reducing remediation costs. The new survey sensor system is called the moving belt metal detector (MBMD) and operates by both increasing sensor speed over the ground while maintaining adequate sensor dwell time over the target for good signal-to-noise ratio (SNR) and reducing motion-induced sensor noise. The MBMD uses an array of metal detection sensors mounted on a flexible belt similar to a tank track. The belt motion is synchronized with the forward survey speed so individual sensor elements remain stationary relative to the ground. A single pulsed transmitter coil is configured to provide a uniform magnetic field along the length of the receivers in ground contact. Individual time-domain electromagnetic induction (EMI) receivers are designed to sense a single time-gate measurement of the total metal content. Each sensor module consists of a receiver coil, amplifier, digitizing electronics and a low power UHF wireless transmitter. This paper presents the survey system design concepts and metal detection data from various targets at several survey speeds. Although the laboratory prototype is designed to demonstrate metal detection survey speeds up to 10 m/s, higher speeds are achievable with a larger sensor array. In addition, the concept can be adapted to work with other sensor technologies not previously considered for moving platforms.

Theoretical investigation of silicide Schottky barrier detector integrated in horizontal metal-insulator-silicon-insulator-metal nanoplasmonic slot waveguide.

PubMed

Zhu, Shiyang; Lo, G Q; Kwong, D L

2011-08-15

An ultracompact integrated silicide Schottky barrier detector (SBD) is designed and theoretically investigated to electrically detect the surface plasmon polariton (SPP) propagating along horizontal metal-insulator-silicon-insulator-metal nanoplasmonic slot waveguides at the telecommunication wavelength of 1550 nm. An ultrathin silicide layer inserted between the silicon core and the insulator, which can be fabricated precisely using the well-developed self-aligned silicide process, absorbs the SPP power effectively if a suitable silicide is chosen. Moreover, the Schottky barrier height in the silicide-silicon-silicide configuration can be tuned substantially by the external voltage through the Schottky effect owing to the very narrow silicon core. For a TaSi(2) detector with optimized dimensions, numerical simulation predicts responsivity of ~0.07 A/W, speed of ~60 GHz, dark current of ~66 nA at room temperature, and minimum detectable power of ~-29 dBm. The design also suggests that the device's size can be reduced and the overall performances will be further improved if a silicide with smaller permittivity is used. © 2011 Optical Society of America

Impacts of metal detector use in schools: insights from 15 years of research.

PubMed

Hankin, Abigail; Hertz, Marci; Simon, Thomas

2011-02-01

Multiple approaches exist, both in theory and in practice, to reduce young people's risk of violent victimization when they are in school. Among these approaches, a growing number of school districts are choosing to install metal detectors. We sought to review the literature available on the impacts of metal detectors on school violence and perceptions about school violence. We conducted an extensive literature search, including databases for the medical, public health, sociology, and political science literature. Of 128 papers that met our search criteria, 7 studies met inclusion criteria for the literature review. Each of the papers reviewed utilized data that originated from self-report surveys. Four of the studies consisted of secondary analyses of national databases, with the other 3 utilizing local surveys. The studies varied as to the outcome, ranging from student/staff perceptions of safety at school to student self-reports of weapon carrying and/or victimization, and showed mixed results. Several studies suggested potential detrimental effects of metal detectors on student perceptions of safety. One study showed a significant beneficial effect, linking metal detector use to a decrease in the likelihood that students reported carrying a weapon while in school (7.8% vs 13.8%), without a change in weapon carrying in other settings or a decline in participation in physical fights. There is insufficient data in the literature to determine whether the presence of metal detectors in schools reduces the risk of violent behavior among students, and some research suggests that the presence of metal detectors may detrimentally impact student perceptions of safety. © Published 2011. This article is a US Government work and is in the public domain in the USA.

Strategies used to walk through a moving aperture.

PubMed

Cinelli, Michael E; Patla, Aftab E; Allard, Fran

2008-05-01

The objectives of the study were to determine what strategy (pursuit or interception) individuals used to pass through an oscillating target and to determine if individuals walked towards where they were looking. Kinematic and gaze behaviour data was collected from seven healthy female participants as they started at one of five different starting positions and walked 7 m towards an oscillating target. The target was a two-dimensional 70 cm aperture made by two-76 cm wide doors and oscillated between two end posts that were 300 cm apart. In order to quantify the objectives, target-heading angles [Fajen BR, Warren WH. Behavioral dynamics of steering, obstacle avoidance, and route selection. J Exp Psychol Hum Percept Perform 2003;29(2):343-62; Fajen BR, Warren WH. Visual guidance of intercepting a moving target on foot. Perception 2004;33:689-715] were calculated. Results showed that the participants used neither an interception nor a pursuit strategy to successfully pass through the moving aperture. The participants steered towards the middle of the pathway prior to passing through the middle of the aperture. A cross correlation between the horizontal gaze locations and the medial/lateral (M/L) location of the participants' center of mass (COM) was performed. The results from the cross correlation show that during the final 2s prior to crossing the aperture, the participants walked where they were looking. The findings from this study suggest that individuals simplify a task by decreasing the perceptual load until the final stages. In this way the final stages of this task were visually driven.

WalkThrough Example Procedures for MAMA

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

Ruggiero, Christy E.; Gaschen, Brian Keith; Bloch, Jeffrey Joseph

This documentation is a growing set of walk through examples of analyses using the MAMA V2.0 software. It does not cover all the features or possibilities with the MAMA software, but will address using many of the basic analysis tools to quantify particle size and shape in an image. This document will continue to evolve as additional procedures and examples are added. The starting assumption is that the MAMA software has been successfully installed.

Impacts of Metal Detector Use in Schools: Insights from 15 Years of Research

ERIC Educational Resources Information Center

Hankin, Abigail; Hertz, Marci; Simon, Thomas

2011-01-01

Background: Multiple approaches exist, both in theory and in practice, to reduce young people's risk of violent victimization when they are in school. Among these approaches, a growing number of school districts are choosing to install metal detectors. We sought to review the literature available on the impacts of metal detectors on school…

[Experimental study on single-electrode metal detector for taking off foreign bodies from the swine].

PubMed

Wang, Li-Gang; Zhang, Gen-Min

2010-06-01

To study the practicability of single-electrode metal detector by using it to take off foreign bodies from swine. The single-electrode metal detector was invented based on the theory of complementary oscillator. Twelve extremities were obtained from 3 Minnesota-Hormel stains 7-month old male swine. All the extremities were divided into 3 groups: lump metal foreign bodies were planted in group A, needle shape metal foreign bodies were planted in group B, and sand shapd metal foreign bodies were planted in group C. The self-invented single-electrode metal detector was used to take off these foreign bodies, and the taking times were recorded. After the operation, the X-ray was used to examine if the foreign bodies were still in the extremities of the swine. The foreign bodies were taken off completely in the 3 groups, and the average time were 38 s, 3 min and 12 s, and 3 min and 59 s respectively. The X-ray examination confirmed that the detector could take off the foreign bodies completely. This detector has satisfactory effect in animal experiment, which could detect and extract metal foreign bodies quickly and exactly without X-ray help duration the operation, and can be used in clinical cases secondly.

Development of a novel polymeric fiber-optic magnetostrictive metal detector.

PubMed

Hua, Wei-Shu; Hooks, Joshua Rosenberg; Wu, Wen-Jong; Wang, Wei-Chih

2010-01-01

The purpose this paper is the development a novel polymeric fiber-optic magnetostrictive metal detector, using a fiber-optic Mach-Zehnder interferometer and polymeric magnetostrictive material. Metal detection is based on the strain-induced optical path length change steming from the ferromagnetic material introduced in the magnetic field. Varied optical phase shifts resulted largely from different metal objects. In this paper, the preliminary results on the different metal material detection will be discussed.

Managing the horn fly (Diptera: Muscidae) using an electric walk-through fly trap.

PubMed

Watson, D W; Stringham, S M; Denning, S S; Washburn, S P; Poore, M H; Meier, A

2002-10-01

An electric walk-through fly trap was evaluated for the management of the horn fly, Hematobia irritans (L.), on dairy cattle in North Carolina over 2 yr. The trap relies on black lights and electrocution grids to attract and kill flies that are brushed from the cattle passing through. During the first season, horn fly densities were reduced from >1,400 to <200 flies per animal. Horn fly density averaged 269.2 +/- 25.8 on cattle using the walk-through fly trap twice daily, and 400.2 +/- 43.5 on the control group during the first year. The second year, seasonal mean horn fly density was 177.3 +/- 10.8 on cattle using the walk-through fly trap compared with 321.1 +/- 15.8 on the control group. No insecticides were used to control horn flies during this 2-yr study.

Identification and topographic localization of metallic foreign bodies by metal detector.

PubMed

Muensterer, Oliver J; Joppich, Ingolf

2004-08-01

Exact localization of ingested metal objects is necessary to guide therapy. This study prospectively evaluates the accuracy of foreign body (FB) identification and localization by metal detector (MTD) in a systematic topographic fashion. Patients who presented after an alleged or witnessed metal FB ingestion were scanned with an MTD. In case of a positive signal, the location was recorded in a topographic diagram, and radiographs were obtained. The diagnostic accuracy of the MTD scan for FB identification and topographic localization was determined by chi(2) analysis, and concordance was calculated by the McNemar test and expressed as kappa. A total of 70 MTD examinations were performed on 65 patients (age 6 months to 16 years); 5 patients were scanned twice on different days. The majority had swallowed coins and button batteries (n = 41). Of these, 29 items were correctly identified, and 11 of 12 were correctly ruled out (coins and button batteries: sensitivity, 100% [95% Confidence Interval 95% to 100%]; specificity, 91.7% [95% CI 76% to 100%], kappa = 0.94). When all metallic objects were included, 41 of 46 were correctly identified, and 22 of 24 were correctly ruled out (sensitivity, 89.1% [95% CI 80% to 98%]; specificity, 91.7% [95% CI 81% to 100%], kappa = 0.78). Five miscellaneous objects were not identified (sensitivity for items other than coins and button batteries 71% [95% CI 49% to 92%], kappa = 0.56). Localization by MTD was correct in 30 of 41 identified objects (73%). The error rates of junior and senior pediatric surgery residents did not differ significantly (P =.82). Ingested coins and button batteries can be safely and accurately found by metal detector. For these indications, the MTD is a radiation-free diagnostic alternative to conventional radiographs. Other items, however, cannot be ruled out reliably by MTD. In these cases, radiographic imaging is still indicated.

The Three-Minute Classroom Walk-Through (Multimedia Kit): A Multimedia Kit for Professional Development

ERIC Educational Resources Information Center

Downey, Carolyn J.; Steffy, Betty E.; English, Fenwick W.; Frase, Larry E.; Poston, William K.

2006-01-01

Showcasing the "Downey Walk-Through"--a method developed over a 40-year period, tested and refined in real-world schools and classrooms, and described in the pioneering book, "The Three-Minute Classroom Walk-Through," this innovative multimedia presentation provides trainers and staff developers with a complete resource answering the questions…

Walking through the Revolution: A Spatial Reading of Literary Echoes

ERIC Educational Resources Information Center

Queiroz, Ana Isabel; Alves, Daniel

2015-01-01

This paper presents an embryo of a literary guide on the Carnation Revolution to be explored for educational historical excursions other than leisure and tourism. We propose a historical trail through the centre of Lisbon, city of the Carnation Revolution, called "Walk through the Revolution." The trail aims to reinforce collective…

Development of a Metal Detector for Smartphones and Its Use in the Teaching Laboratory

ERIC Educational Resources Information Center

Sobral, Geraldo A.

2018-01-01

In this article, we describe how to develop an inductive metal detector that can be integrated to any Android or iOS smartphone with a standard audio port at low cost. The results indicate the metal detector can be used in the physics teaching laboratory as a practical application of principles of electromagnetism. It allows one to differentiate…

Reduced γ-γ time walk to below 50 ps using the multiplexed-start and multiplexed-stop fast-timing technique with LaBr3(Ce) detectors

NASA Astrophysics Data System (ADS)

Régis, J.-M.; Saed-Samii, N.; Rudigier, M.; Ansari, S.; Dannhoff, M.; Esmaylzadeh, A.; Fransen, C.; Gerst, R.-B.; Jolie, J.; Karayonchev, V.; Müller-Gatermann, C.; Stegemann, S.

2016-07-01

The electronic γ-γ fast-timing technique using arrays consisting of many LaBr3(Ce) detectors is a powerful method to determine lifetimes of nuclear excited states with a lower limit of about 5 ps. This method requires the determination of the energy-dependent time walk of the zero time which is represented by the centroid of a prompt γ-γ time distribution. The full-energy peak versus full-energy peak prompt response difference which represents the linearly combined mean γ-γ time walk of a fast-timing array consisting of 8 LaBr3(Ce) detectors was measured using a standard 152Eu γ-ray source for the energy region of 40-1408 keV. The data were acquired using a "multiplexed-start and multiplexed-stop" analogue electronics circuitry and analysed by employing the generalized centroid difference method. Concerning the cylindrical 1.5 in.×1.5 in. LaBr3(Ce) crystals which are coupled to the Hamamatsu R9779 photomultiplier tubes, the best fast-timing array time resolution of 202(3) ps is obtained for the two prompt γ lines of 60Co by using the leading-edge timing principle. When using the zero-crossover timing principle the time resolution is degraded by up to 30%, dependent on the energy and the shaping delay time of the constant fraction discriminator model Ortec 935. The smallest γ-γ time walk to below 50 ps is obtained by using a shaping delay time of about 17 ns and an optimum "time-walk adjustment" needed for detector output pulses with amplitudes smaller than 400 mV.

Super sensitive UV detector using polymer functionalized nanobelts

DOEpatents

Wang, Zhong L; Lao, Changshi; Zhou, Jun

2012-10-23

An ultraviolet light sensor includes an elongated metal oxide nanostructure, a layer of an ultraviolet light-absorbing polymer, a current source and a current detector. The elongated metal oxide nanostructure has a first end and an opposite second end. The layer of an ultraviolet light-absorbing polymer is disposed about at least a portion of the metal oxide nanostructure. The current source is configured to provide electrons to the first end of the metal oxide nanostructure. The current detector is configured to detect an amount of current flowing through the metal oxide nanostructure. The amount of current flowing through the metal oxide nanostructure corresponds to an amount of ultraviolet light impinging on the metal oxide nanostructure.

Adolescent Literacy Walk-Through for Principals: A Guide for Instructional Leaders

ERIC Educational Resources Information Center

Rissman, Lila M.; Miller, Debra H.; Torgesen, Joseph K.

2009-01-01

The purpose of this "Adolescent Literacy Walk-Through for Principals" ("ALWP") is to help principals monitor and support adolescent literacy instruction in their schools more effectively. To meet the goals of improving adolescent literacy in grades four through twelve, principals must be familiar with what literacy instruction…

Generation of Nonclassical Biphoton States through Cascaded Quantum Walks on a Nonlinear Chip

NASA Astrophysics Data System (ADS)

Solntsev, Alexander S.; Setzpfandt, Frank; Clark, Alex S.; Wu, Che Wen; Collins, Matthew J.; Xiong, Chunle; Schreiber, Andreas; Katzschmann, Fabian; Eilenberger, Falk; Schiek, Roland; Sohler, Wolfgang; Mitchell, Arnan; Silberhorn, Christine; Eggleton, Benjamin J.; Pertsch, Thomas; Sukhorukov, Andrey A.; Neshev, Dragomir N.; Kivshar, Yuri S.

2014-07-01

We demonstrate a nonlinear optical chip that generates photons with reconfigurable nonclassical spatial correlations. We employ a quadratic nonlinear waveguide array, where photon pairs are generated through spontaneous parametric down-conversion and simultaneously spread through quantum walks between the waveguides. Because of the quantum interference of these cascaded quantum walks, the emerging photons can become entangled over multiple waveguide positions. We experimentally observe highly nonclassical photon-pair correlations, confirming the high fidelity of on-chip quantum interference. Furthermore, we demonstrate biphoton-state tunability by spatial shaping and frequency tuning of the classical pump beam.

Magneto-Radar Hidden Metal Detector

DOEpatents

McEwan, Thomas E.

2005-07-05

A varying magnetic field excites slight vibrations in an object and a radar sensor detects the vibrations at a harmonic of the excitation frequency. The synergy of the magnetic excitation and radar detection provides increased detection range compared to conventional magnetic metal detectors. The radar rejects background clutter by responding only to reflecting objects that are vibrating at a harmonic excitation field, thereby significantly improving detection reliability. As an exemplary arrangement, an ultra-wideband micropower impulse radar (MIR) is capable of being employed to provide superior materials penetration while providing range information. The magneto-radar may be applied to pre-screening magnetic resonance imaging (MRI) patients, landmine detection and finding hidden treasures.

Implementing metal detector technology and a navigation system in the removal of shrapnel.

PubMed

Peleg, Eran; Harari, Meytal; Liebergall, Meir; Mosheiff, Rami

2009-01-01

The removal of metal shrapnel in the sub-acute phase of casualty treatment requires the utmost accuracy in detection and removal, especially when there is proximity to major neurovascular structures. Inability to successfully locate and remove retained fragments may lead to a variety of complications due to fragment migration. In this study we prove the feasibility of a new technique which uses metal detector technology combined with a surgical navigation system, resulting in improved accuracy and decreased operating time. In each of the experiments, 6 metal nuts were inserted into a dummy leg to simulate shrapnel wounds. Two major experiments were then conducted. Experiment 1 was a comparison of two methods: (a) localization of the nuts using surgical navigation alone, and (b) localization by means of metal detector technology combined with a surgical navigation system (StealthStation® TREON® plus). Experiment 2 employed the same two methods, but this time migration of the metal fragments was introduced. The localization time was measured from incision of the dummy skin to the moment the metal fragment was touched by the searching device. In experiment 1 the results showed no significant differences between the two approaches. In experiment 2 the new technique was found to significantly decrease the mean fragment localization time, taking 9.6 seconds (±7.2 seconds) as compared to 26.4 seconds (±13.8 seconds) when using the regular technique. Combining a metal detector probe and a surgical navigation system was found to significantly decrease operating time and increase the surgeon's confidence, especially in cases where migration of the metal fragment occurred during searching and extraction.

Using Metal Detectors in the Public Schools: Some Legal Issues.

ERIC Educational Resources Information Center

Bjorklun, Eugene C.

1996-01-01

Examines two legal issues related to the use of metal detectors in public schools: their legality under the Fourth Amendment and the potential liability of schools who fail to use them to keep weapons out of their buildings. (91 footnotes) (MLF)

Walking through doorways causes forgetting: Younger and older adults.

PubMed

Radvansky, Gabriel A; Pettijohn, Kyle A; Kim, Joonsung

2015-06-01

Previous research on event cognition has found that walking through doorways can cause forgetting. The explanation for this finding is that there is a competition between event models, producing interference, and depressing performance. The current study explored the degree to which this might be affected by the natural aging process. This is of interest because there is some evidence that older adults have trouble coordinating sources of interference, which is what is thought to underlie this effect. This would suggest that older adults should do worse on this task. Alternatively, there is also evidence that older adults are typically not disrupted at the event level of processing per se. This would suggest that older adults should perform similarly to younger adults on this task. In the study reported here, younger and older participants navigated through a virtual environment, and memory was tested with probes either before or after a shift and for objects that were associated with the participant (i.e., just picked up). In general, both younger and older adults had memory disrupted after walking through a doorway. Importantly, the magnitude of this disruption was similar in the 2 age groups. This is consistent with the idea that processing at the event level is relatively unaffected by the natural aging process. (PsycINFO Database Record (c) 2015 APA, all rights reserved).

Walk-through survey report: Control technology for metal reclamation industries at Exide/General Battery Corporation, Reading, Pennsylvania

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

Hall, R.M.

1994-03-30

A walk through survey was made at Exide/General Battery Corporation, Reading, Pennsylvania to identify and evaluate control methods to reduce lead exposure. About 20,000 to 25,000 batteries a day were recycled, primarily automobile batteries. Lead and plastic from the batteries were reclaimed. The company used local exhaust ventilation, enclosed ventilated booths, partial enclosures, and automated operations throughout production areas of the site. Various occupational safety and health programs were in place including occupational and safety training, a respiratory protection program, various hygiene programs, and blood lead monitoring programs. These findings will be compared with those from other sites and themore » facility with the lowest lead exposure levels will be examined carefully so that others may be brought in line with the best of standards.« less

NHEXAS PHASE I ARIZONA STUDY--STANDARD OPERATING PROCEDURE FOR CODING: TECHNICIAN WALK-THROUGH QUESTIONNAIRE (UA-D-35.0)

EPA Science Inventory

The purpose of this SOP is to define the coding strategy for the Technician Walk-Through Questionnaire. This questionnaire was developed for use during the Arizona NHEXAS project and the "Border" study. Keywords: data; coding; technician walk-through questionnaire.

The Nationa...

NHEXAS PHASE I ARIZONA STUDY--STANDARD OPERATING PROCEDURE FOR CLEANING: TECHNICIAN WALK-THROUGH QUESTIONNAIRE (UA-D-36.0)

EPA Science Inventory

The purpose of this SOP is to define the steps involved in cleaning the electronic data generated from data entry of the Technician Walk-Through Questionnaire. It applies to electronic data corresponding to the Technician Walk-Through Questionnaire that was scanned and verified ...

Development of a metal detector for smartphones and its use in the teaching laboratory

NASA Astrophysics Data System (ADS)

Sobral, G. A.

2018-07-01

In this article, we describe how to develop an inductive metal detector that can be integrated to any Android or iOS smartphone with a standard audio port at low cost. The results indicate the metal detector can be used in the physics teaching laboratory as a practical application of principles of electromagnetism. It allows one to differentiate ferromagnetic samples from the diamagnetic and paramagnetic ones and can also be used to investigate the direction of alternating magnetic fields and to demonstrate the Faraday’s cage shielding effect.

Pyroelectric detector arrays

NASA Technical Reports Server (NTRS)

Fripp, A. L.; Robertson, J. B.; Breckenridge, R. (Inventor)

1982-01-01

A pyroelectric detector array and the method for using it are described. A series of holes formed through a silicon dioxide layer on the surface of a silicon substrate forms the mounting fixture for the pyroelectric detector array. A series of nontouching strips of indium are formed around the holes to make contact with the backside electrodes and form the output terminals for individual detectors. A pyroelectric detector strip with front and back electrodes, respectively, is mounted over the strips. Biasing resistors are formed on the surface of the silicon dioxide layer and connected to the strips. A metallized pad formed on the surface of layer is connected to each of the biasing resistors and to the film to provide the ground for the pyroelectric detector array.

Sensory substitution information informs locomotor adjustments when walking through apertures.

PubMed

Kolarik, Andrew J; Timmis, Matthew A; Cirstea, Silvia; Pardhan, Shahina

2014-03-01

The study assessed the ability of the central nervous system (CNS) to use echoic information from sensory substitution devices (SSDs) to rotate the shoulders and safely pass through apertures of different width. Ten visually normal participants performed this task with full vision, or blindfolded using an SSD to obtain information regarding the width of an aperture created by two parallel panels. Two SSDs were tested. Participants passed through apertures of +0, +18, +35 and +70 % of measured body width. Kinematic indices recorded movement time, shoulder rotation, average walking velocity across the trial, peak walking velocities before crossing, after crossing and throughout a whole trial. Analyses showed participants used SSD information to regulate shoulder rotation, with greater rotation associated with narrower apertures. Rotations made using an SSD were greater compared to vision, movement times were longer, average walking velocity lower and peak velocities before crossing, after crossing and throughout the whole trial were smaller, suggesting greater caution. Collisions sometimes occurred using an SSD but not using vision, indicating that substituted information did not always result in accurate shoulder rotation judgements. No differences were found between the two SSDs. The data suggest that spatial information, provided by sensory substitution, allows the relative position of aperture panels to be internally represented, enabling the CNS to modify shoulder rotation according to aperture width. Increased buffer space indicated by greater rotations (up to approximately 35 % for apertures of +18 % of body width) suggests that spatial representations are not as accurate as offered by full vision.

Probing infrared detectors through energy-absorption interferometry

NASA Astrophysics Data System (ADS)

Moinard, Dan; Withington, Stafford; Thomas, Christopher N.

2017-08-01

We describe an interferometric technique capable of fully characterizing the optical response of few-mode and multi-mode detectors using only power measurements, and its implementation at 1550 nm wavelength. EnergyAbsorption Interferometry (EAI) is an experimental procedure where the system under test is excited with two coherent, phase-locked sources. As the relative phase between the sources is varied, a fringe is observed in the detector output. Iterating over source positions, the fringes' complex visibilities allow the two-point detector response function to be retrieved: this correlation function corresponds to the state of coherence to which the detector is maximally sensitive. This detector response function can then be decomposed into a set of natural modes, in which the detector is incoherently sensitive to power. EAI therefore allows the reconstruction of the individual degrees of freedom through which the detector can absorb energy, including their relative sensitivities and full spatial forms. Coupling mechanisms into absorbing structures and their underlying solidstate phenomena can thus be studied, with direct applications in improving current infrared detector technology. EAI has previously been demonstrated for millimeter wavelength. Here, we outline the theoretical basis of EAI, and present a room-temperature 1550 nm wavelength infrared experiment we have constructed. Finally, we discuss how this experimental system will allow us to study optical coupling into fiber-based systems and near-infrared detectors.

Spectroscopic micro-tomography of metallic-organic composites by means of photon-counting detectors

NASA Astrophysics Data System (ADS)

Pichotka, M.; Jakubek, J.; Vavrik, D.

2015-12-01

The presumed capabilities of photon counting detectors have aroused major expectations in several fields of research. In the field of nuclear imaging ample benefits over standard detectors are to be expected from photon counting devices. First of all a very high contrast, as has by now been verified in numerous experiments. The spectroscopic capabilities of photon counting detectors further allow material decomposition in computed tomography and therefore inherently adequate beam hardening correction. For these reasons measurement setups featuring standard X-ray tubes combined with photon counting detectors constitute a possible replacement of the much more cost intensive tomographic setups at synchrotron light-sources. The actual application of photon counting detectors in radiographic setups in recent years has been impeded by a number of practical issues, above all by restrictions in the detectors size. Currently two tomographic setups in Czech Republic feature photon counting large-area detectors (LAD) fabricated in Prague. The employed large area hybrid pixel-detector assemblies [1] consisting of 10×10/10×5 Timepix devices have a surface area of 143×143 mm2 / 143×71,5 mm2 respectively, suitable for micro-tomographic applications. In the near future LAD devices featuring the Medipix3 readout chip as well as heavy sensors (CdTe, GaAs) will become available. Data analysis is obtained by a number of in house software tools including iterative multi-energy volume reconstruction.In this paper tomographic analysis of of metallic-organic composites is employed to illustrate the capabilities of our technology. Other than successful material decomposition by spectroscopic tomography we present a method to suppress metal artefacts under certain conditions.

Technique for detecting liquid metal leaks

DOEpatents

Bauerle, James E.

1979-01-01

In a system employing flowing liquid metal as a heat transfer medium in contact with tubular members containing a working fluid, i.e., steam, liquid metal leaks through the wall of the tubular member are detected by dislodging the liquid metal compounds forming in the tubular member at the leak locations and subsequently transporting the dislodged compound in the form of an aerosol to a detector responsive to the liquid metal compound. In the application to a sodium cooled tubular member, the detector would consist of a sodium responsive device, such as a sodium ion detector.

Metallic wire grid behavior and testing in a low pressure gaseous noble elements detector

NASA Astrophysics Data System (ADS)

Ji, W.

2018-05-01

High voltage performance has been a challenge for noble element detectors. One piece of this challenge is the emission of electrons from metal electrodes when applying high voltage. This has become a major concern for low-background detectors such as LUX-ZEPLIN (LZ). LZ is a liquid xenon Time Projection Chamber (TPC) searching for Weakly Interactive Massive Particles (WIMPs). In this work, we demonstrate a method to measure electron emission from metallic electrode grids via detection of proportional scintillation light. We find consistency with Fowler-Nordheim emission with a surface parameter β = 1988 after electro-polishing treatment of a stainless steel grid.

Pyroelectric detector arrays

NASA Technical Reports Server (NTRS)

Fripp, A. L.; Robertson, J. B.; Breckenridge, R. A. (Inventor)

1982-01-01

A pryoelectric detector array and the method for making it are described. A series of holes formed through a silicon dioxide layer on the surface of a silicon substrate forms the mounting fixture for the pyroelectric detector array. A series of nontouching strips of indium are formed around the holes to make contact with the backside electrodes and form the output terminals for individual detectors. A pyroelectric detector strip with front and back electrodes, respectively, is mounted over the strip. Biasing resistors are formed on the surface of the silicon dioxide layer and connected to the strips. A metallized pad formed on the surface of the layer is connected to each of the biasing resistors and to the film to provide the ground for the pyroelectric detector array.

The Use of Classroom Walk-Through Observations as a Strategy to Improve Teaching and Learning: An Administrative Perspective

ERIC Educational Resources Information Center

Weller, Mark J.

2010-01-01

The purpose of this study was to identify the possible use of structured classroom walk-through observations as a strategy to improve teaching and learning. A wide variety of programs and initiatives have recently been implemented across the country to improve student achievement. One such initiative is classroom walk-through observations.…

MSM-Metal Semiconductor Metal Photo-detector Using Black Silicon Germanium (SiGe) for Extended Wavelength Near Infrared Detection

DTIC Science & Technology

2012-09-01

MSM) photodectors fabricated using black silicon-germanium on silicon substrate (Si1–xGex//Si) for I-V, optical response, external quantum ...material for Si for many applications in low-power and high-speed semiconductor device technologies (4, 5). It is a promising material for quantum well ...MSM-Metal Semiconductor Metal Photo-detector Using Black Silicon Germanium (SiGe) for Extended Wavelength Near Infrared Detection by Fred

Virtual Walk: The Construction of the Long Baseline Neutrino Facility

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

None

This 2-minute animation shows a virtual walk through the large caverns of the Long-Baseline Neutrino Facility, which will house the Deep Underground Neutrino Experiment. To create the caverns for the huge DUNE particle detectors, construction crews will excavate more than 800,000 tons of rock a mile underground at the Sanford Underground Research Facility in South Dakota. Scientists and dignitaries broke ground for this project on July 21, 2017. When construction is complete, DUNE scientists will send an intense neutrino beam through 1,300 kilometers of rock from the Department of Energy’s Fermilab to the DUNE particle detectors to understand the rolemore » that neutrinos – the most abundant matter particles in the universe – play in our cosmos. About 1,000 scientists from more than 160 institutions in 30 countries work on the Deep Underground Neutrino Experiment.« less

Factors influencing quality of patient interaction at community pharmacy drive-through and walk-in counselling areas.

PubMed

Odukoya, Olufunmilola K; Chui, Michelle A; Pu, Jia

2014-08-01

To examine factors influencing the amount of time and information pharmacy personnel provide to patients at drive-through and walk-in counselling areas. On-site observational data collection in 22 community pharmacies by pharmacy students. Information included observable patient characteristics such as gender, age range, English proficiency and mobility impairment; encounter characteristics included type of prescription and whether the patient was acknowledged; and counselling characteristics included types of counselling information conveyed and length of time for each encounter. Patient-pharmacist encounters were documented at the drive-through and walk-in counselling areas 961 and 1098 times respectively. Pharmacists spent less time, and technicians more time, with patients at the drive-through counselling area. The amount of information provided to patients was significantly affected by whether the patient was receiving new versus refill prescriptions. Patients with a new prescription were twice as likely to receive more information from pharmacy personnel. There was a significant difference between the amount of counselling provided to patients at the drive-through and walk-in counselling area (rate ratio (RR) 0.92, 95% confidence interval (CI): 0.86-1.00). Patients at the drive-through received a lower amount of information relative to patients using the walk-in. Amount of information provided to patients was affected by the level of pharmacy busyness (RR 0.96, 95% CI: 0.95-0.99). Providing patient care at the drive-through counselling area may negatively influence quality of patient care. To improve quality of pharmacy drive-through services, standardization of drive-through services in pharmacies may be needed. © 2013 Royal Pharmaceutical Society.

Artifact reduction of different metallic implants in flat detector C-arm CT.

PubMed

Hung, S-C; Wu, C-C; Lin, C-J; Guo, W-Y; Luo, C-B; Chang, F-C; Chang, C-Y

2014-07-01

Flat detector CT has been increasingly used as a follow-up examination after endovascular intervention. Metal artifact reduction has been successfully demonstrated in coil mass cases, but only in a small series. We attempted to objectively and subjectively evaluate the feasibility of metal artifact reduction with various metallic objects and coil lengths. We retrospectively reprocessed the flat detector CT data of 28 patients (15 men, 13 women; mean age, 55.6 years) after they underwent endovascular treatment (20 coiling ± stent placement, 6 liquid embolizers) or shunt drainage (n = 2) between January 2009 and November 2011 by using a metal artifact reduction correction algorithm. We measured CT value ranges and noise by using region-of-interest methods, and 2 experienced neuroradiologists rated the degrees of improved imaging quality and artifact reduction by comparing uncorrected and corrected images. After we applied the metal artifact reduction algorithm, the CT value ranges and the noise were substantially reduced (1815.3 ± 793.7 versus 231.7 ± 95.9 and 319.9 ± 136.6 versus 45.9 ± 14.0; both P < .001) regardless of the types of metallic objects and various sizes of coil masses. The rater study achieved an overall improvement of imaging quality and artifact reduction (85.7% and 78.6% of cases by 2 raters, respectively), with the greatest improvement in the coiling group, moderate improvement in the liquid embolizers, and the smallest improvement in ventricular shunting (overall agreement, 0.857). The metal artifact reduction algorithm substantially reduced artifacts and improved the objective image quality in every studied case. It also allowed improved diagnostic confidence in most cases. © 2014 by American Journal of Neuroradiology.

Multi-detector CT imaging in the postoperative orthopedic patient with metal hardware.

PubMed

Vande Berg, Bruno; Malghem, Jacques; Maldague, Baudouin; Lecouvet, Frederic

2006-12-01

Multi-detector CT imaging (MDCT) becomes routine imaging modality in the assessment of the postoperative orthopedic patients with metallic instrumentation that degrades image quality at MR imaging. This article reviews the physical basis and CT appearance of such metal-related artifacts. It also addresses the clinical value of MDCT in postoperative orthopedic patients with emphasis on fracture healing, spinal fusion or arthrodesis, and joint replacement. MDCT imaging shows limitations in the assessment of the bone marrow cavity and of the soft tissues for which MR imaging remains the imaging modality of choice despite metal-related anatomic distortions and signal alteration.

Visual task performance using a monocular see-through head-mounted display (HMD) while walking.

PubMed

Mustonen, Terhi; Berg, Mikko; Kaistinen, Jyrki; Kawai, Takashi; Häkkinen, Jukka

2013-12-01

A monocular see-through head-mounted display (HMD) allows the user to view displayed information while simultaneously interacting with the surrounding environment. This configuration lets people use HMDs while they are moving, such as while walking. However, sharing attention between the display and environment can compromise a person's performance in any ongoing task, and controlling one's gait may add further challenges. In this study, the authors investigated how the requirements of HMD-administered visual tasks altered users' performance while they were walking. Twenty-four university students completed 3 cognitive tasks (high- and low-working memory load, visual vigilance) on an HMD while seated and while simultaneously performing a paced walking task in a controlled environment. The results show that paced walking worsened performance (d', reaction time) in all HMD-administered tasks, but visual vigilance deteriorated more than memory performance. The HMD-administered tasks also worsened walking performance (speed, path overruns) in a manner that varied according to the overall demands of the task. These results suggest that people's ability to process information displayed on an HMD may worsen while they are in motion. Furthermore, the use of an HMD can critically alter a person's natural performance, such as their ability to guide and control their gait. In particular, visual tasks that involve constant monitoring of the HMD should be avoided. These findings highlight the need for careful consideration of the type and difficulty of information that can be presented through HMDs while still letting the user achieve an acceptable overall level of performance in various contexts of use. PsycINFO Database Record (c) 2013 APA, all rights reserved.

The Use of Classroom Walk-Through Observations as a Strategy to Improve Teaching and Learning: A Student Centered Perspective

ERIC Educational Resources Information Center

Sorensen, Thomas R., Jr.

2010-01-01

Due to the increasing pressure of meeting the demands of No Child Left Behind, and reducing the achievement gap between subgroups of school populations, school administrators across the nation have implemented a variety of short classroom walk-through observations. A walk-through is defined as a 3-5 minute observation of the classroom teacher by…

Okaying the Use of Metal Detectors Proves Easier than Actually Using Them.

ERIC Educational Resources Information Center

Stelly, Philip

1984-01-01

Discusses legal problems of a policy permitting the use of metal detectors to search students suspected of carrying concealed weapons. A wholesale search policy was challenged as a violation of students' rights, so the board adopted a selective search policy based on reasonable suspicion. (TE)

The Walking Interventions Through Texting (WalkIT) Trial: Rationale, Design, and Protocol for a Factorial Randomized Controlled Trial of Adaptive Interventions for Overweight and Obese, Inactive Adults.

PubMed

Hurley, Jane C; Hollingshead, Kevin E; Todd, Michael; Jarrett, Catherine L; Tucker, Wesley J; Angadi, Siddhartha S; Adams, Marc A

2015-09-11

Walking is a widely accepted and frequently targeted health promotion approach to increase physical activity (PA). Interventions to increase PA have produced only small improvements. Stronger and more potent behavioral intervention components are needed to increase time spent in PA, improve cardiometabolic risk markers, and optimize health. Our aim is to present the rationale and methods from the WalkIT Trial, a 4-month factorial randomized controlled trial (RCT) in inactive, overweight/obese adults. The main purpose of the study was to evaluate whether intensive adaptive components result in greater improvements to adults' PA compared to the static intervention components. Participants enrolled in a 2x2 factorial RCT and were assigned to one of four semi-automated, text message-based walking interventions. Experimental components included adaptive versus static steps/day goals, and immediate versus delayed reinforcement. Principles of percentile shaping and behavioral economics were used to operationalize experimental components. A Fitbit Zip measured the main outcome: participants' daily physical activity (steps and cadence) over the 4-month duration of the study. Secondary outcomes included self-reported PA, psychosocial outcomes, aerobic fitness, and cardiorespiratory risk factors assessed pre/post in a laboratory setting. Participants were recruited through email listservs and websites affiliated with the university campus, community businesses and local government, social groups, and social media advertising. This study has completed data collection as of December 2014, but data cleaning and preliminary analyses are still in progress. We expect to complete analysis of the main outcomes in late 2015 to early 2016. The Walking Interventions through Texting (WalkIT) Trial will further the understanding of theory-based intervention components to increase the PA of men and women who are healthy, insufficiently active and are overweight or obese. WalkIT is one of

Walking Wellness. Student Workbook.

ERIC Educational Resources Information Center

Sweetgall, Robert; Neeves, Robert

This comprehensive student text and workbook, for grades four through eight, contains 16 workshop units focusing on walking field trips, aerobic pacing concepts, walking techniques, nutrition, weight control and healthy life-style planning. Co-ordinated homework assignments are included. The appendixes include 10 tips for walking, a calorie chart,…

U.S.-MEXICO BORDER PROGRAM ARIZONA BORDER STUDY--STANDARD OPERATING PROCEDURE FOR CLEANING: TECHNICIAN WALK-THROUGH QUESTIONNAIRE (UA-D-36.0)

EPA Science Inventory

The purpose of this SOP is to define the steps involved in cleaning the electronic data generated from data entry of the Technician Walk-Through Questionnaire. It applies to electronic data corresponding to the Technician Walk-Through Questionnaire that was scanned and verified ...

Measuring graph similarity through continuous-time quantum walks and the quantum Jensen-Shannon divergence.

PubMed

Rossi, Luca; Torsello, Andrea; Hancock, Edwin R

2015-02-01

In this paper we propose a quantum algorithm to measure the similarity between a pair of unattributed graphs. We design an experiment where the two graphs are merged by establishing a complete set of connections between their nodes and the resulting structure is probed through the evolution of continuous-time quantum walks. In order to analyze the behavior of the walks without causing wave function collapse, we base our analysis on the recently introduced quantum Jensen-Shannon divergence. In particular, we show that the divergence between the evolution of two suitably initialized quantum walks over this structure is maximum when the original pair of graphs is isomorphic. We also prove that under special conditions the divergence is minimum when the sets of eigenvalues of the Hamiltonians associated with the two original graphs have an empty intersection.

U.S.-MEXICO BORDER PROGRAM ARIZONA BORDER STUDY--STANDARD OPERATING PROCEDURE FOR CODING: TECHNICIAN WALK-THROUGH QUESTIONNAIRE (UA-D-35.0)

EPA Science Inventory

The purpose of this SOP is to define the coding strategy for the Technician Walk-Through Questionnaire. This questionnaire was developed for use during the Arizona NHEXAS project and the Border study. Keywords: data; coding; technician walk-through questionnaire.

The U.S.-Mexi...

A novel forward projection-based metal artifact reduction method for flat-detector computed tomography.

PubMed

Prell, Daniel; Kyriakou, Yiannis; Beister, Marcel; Kalender, Willi A

2009-11-07

Metallic implants generate streak-like artifacts in flat-detector computed tomography (FD-CT) reconstructed volumetric images. This study presents a novel method for reducing these disturbing artifacts by inserting discarded information into the original rawdata using a three-step correction procedure and working directly with each detector element. Computation times are minimized by completely implementing the correction process on graphics processing units (GPUs). First, the original volume is corrected using a three-dimensional interpolation scheme in the rawdata domain, followed by a second reconstruction. This metal artifact-reduced volume is then segmented into three materials, i.e. air, soft-tissue and bone, using a threshold-based algorithm. Subsequently, a forward projection of the obtained tissue-class model substitutes the missing or corrupted attenuation values directly for each flat detector element that contains attenuation values corresponding to metal parts, followed by a final reconstruction. Experiments using tissue-equivalent phantoms showed a significant reduction of metal artifacts (deviations of CT values after correction compared to measurements without metallic inserts reduced typically to below 20 HU, differences in image noise to below 5 HU) caused by the implants and no significant resolution losses even in areas close to the inserts. To cover a variety of different cases, cadaver measurements and clinical images in the knee, head and spine region were used to investigate the effectiveness and applicability of our method. A comparison to a three-dimensional interpolation correction showed that the new approach outperformed interpolation schemes. Correction times are minimized, and initial and corrected images are made available at almost the same time (12.7 s for the initial reconstruction, 46.2 s for the final corrected image compared to 114.1 s and 355.1 s on central processing units (CPUs)).

The Walking Interventions Through Texting (WalkIT) Trial: Rationale, Design, and Protocol for a Factorial Randomized Controlled Trial of Adaptive Interventions for Overweight and Obese, Inactive Adults

PubMed Central

Hurley, Jane C; Hollingshead, Kevin E; Todd, Michael; Jarrett, Catherine L; Tucker, Wesley J; Angadi, Siddhartha S

2015-01-01

Background Walking is a widely accepted and frequently targeted health promotion approach to increase physical activity (PA). Interventions to increase PA have produced only small improvements. Stronger and more potent behavioral intervention components are needed to increase time spent in PA, improve cardiometabolic risk markers, and optimize health. Objective Our aim is to present the rationale and methods from the WalkIT Trial, a 4-month factorial randomized controlled trial (RCT) in inactive, overweight/obese adults. The main purpose of the study was to evaluate whether intensive adaptive components result in greater improvements to adults’ PA compared to the static intervention components. Methods Participants enrolled in a 2x2 factorial RCT and were assigned to one of four semi-automated, text message–based walking interventions. Experimental components included adaptive versus static steps/day goals, and immediate versus delayed reinforcement. Principles of percentile shaping and behavioral economics were used to operationalize experimental components. A Fitbit Zip measured the main outcome: participants’ daily physical activity (steps and cadence) over the 4-month duration of the study. Secondary outcomes included self-reported PA, psychosocial outcomes, aerobic fitness, and cardiorespiratory risk factors assessed pre/post in a laboratory setting. Participants were recruited through email listservs and websites affiliated with the university campus, community businesses and local government, social groups, and social media advertising. Results This study has completed data collection as of December 2014, but data cleaning and preliminary analyses are still in progress. We expect to complete analysis of the main outcomes in late 2015 to early 2016. Conclusions The Walking Interventions through Texting (WalkIT) Trial will further the understanding of theory-based intervention components to increase the PA of men and women who are healthy, insufficiently

Image-based 3D reconstruction and virtual environmental walk-through

NASA Astrophysics Data System (ADS)

Sun, Jifeng; Fang, Lixiong; Luo, Ying

2001-09-01

We present a 3D reconstruction method, which combines geometry-based modeling, image-based modeling and rendering techniques. The first component is an interactive geometry modeling method which recovery of the basic geometry of the photographed scene. The second component is model-based stereo algorithm. We discus the image processing problems and algorithms of walking through in virtual space, then designs and implement a high performance multi-thread wandering algorithm. The applications range from architectural planning and archaeological reconstruction to virtual environments and cinematic special effects.

Orange Is the New Who: Reflections on Teaching a College-Level Art Appreciation Course at Six New Jersey State Prisons

ERIC Educational Resources Information Center

McGuire, J. D.

2017-01-01

The process of entering prison as a civilian is such … sign in … send stuff through x-ray … walk through metal detector … get patted down by officer … show badge, get buzzed through steel door … get buzzed through another steel door … get buzzed through another steel door … show badge to officer, get buzzed through steel door. Enter the yard and…

Design and field results of a walk-through EDS

NASA Astrophysics Data System (ADS)

Wendel, Gregory J.; Bromberg, Edward E.; Durfee, Memorie K.; Curby, William A.

1997-01-01

A walk-through portal sampling module which incorporates active sampling has been developed. The module uses opposing wands which actively brush the subjects exterior clothing to disturb explosive traces. These traces are entrained in an air stream and transported to a High Speed GC- chemiluminescence explosives detection system. This combination provides automatic screening of passengers at rates of 10 per minute. The system exhibits sensitivity and selectivity which equals or betters that available from commercially available manual equipment. The systems has been developed for deployment at border crossings, airports and other security screening points. Detailed results of laboratory tests and airport field trials are reviewed.

Guiding Students through Expository Text with Text Feature Walks

ERIC Educational Resources Information Center

Kelley, Michelle J.; Clausen-Grace, Nicki

2010-01-01

The Text Feature Walk is a structure created and employed by the authors that guides students in the reading of text features in order to access prior knowledge, make connections, and set a purpose for reading expository text. Results from a pilot study are described in order to illustrate the benefits of using the Text Feature Walk over…

Modular multi-element high energy particle detector

DOEpatents

Coon, Darryl D.; Elliott, John P.

1990-01-02

Multi-element high energy particle detector modules comprise a planar heavy metal carrier of tungsten alloy with planar detector units uniformly distributed over one planar surface. The detector units are secured to the heavy metal carrier by electrically conductive adhesive so that the carrier serves as a common ground. The other surface of each planar detector unit is electrically connected to a feedthrough electrical terminal extending through the carrier for front or rear readout. The feedthrough electrical terminals comprise sockets at one face of the carrier and mating pins porjecting from the other face, so that any number of modules may be plugged together to create a stack of modules of any desired number of radiation lengths. The detector units each comprise four, preferably rectangular, p-i-n diode chips arranged around the associated feedthrough terminal to form a square detector unit providing at least 90% detector element coverage of the carrier. Integral spacers projecting from the carriers extend at least partially along the boundaries between detector units to space the p-i-n diode chips from adjacent carriers in a stack. The spacers along the perimeters of the modules are one-half the width of the interior spacers so that when stacks of modules are arranged side by side to form a large array of any size or shape, distribution of the detector units is uniform over the entire array.

Metal Detector Searches: An Effective Means To Help Keep Weapons Out of Schools.

ERIC Educational Resources Information Center

Johnson, Robert S.

2000-01-01

Disagrees with Ferraraccio's views and argues that: (1) students do bring illegal weapons to school; (2) metal detectors do detect weapons and help schools to disarm students; (3) disarming students reduces the threat of violence; and (4) courts have repeatedly approved the constitutionality of weapon-related suspicionless student searches…

Low pressure ion chromatography with a low cost paired emitter-detector diode based detector for the determination of alkaline earth metals in water samples.

PubMed

Barron, Leon; Nesterenko, Pavel N; Diamond, Dermot; O'Toole, Martina; Lau, King Tong; Paull, Brett

2006-09-01

The use of a low pressure ion chromatograph based upon short (25 mm x 4.6 mm) surfactant coated monolithic columns and a low cost paired emitter-detector diode (PEDD) based detector, for the determination of alkaline earth metals in aqueous matrices is presented. The system was applied to the separation of magnesium, calcium, strontium and barium in less than 7min using a 0.15M KCl mobile phase at pH 3, with post-column reaction detection at 570 nm using o-cresolphthalein complexone. A comparison of the performance of the PEDD detector with a standard laboratory absorbance detector is shown, with limits of detection for magnesium and calcium using the low cost PEDD detector equal to 0.16 and 0.23 mg L(-1), respectively. Finally, the developed system was used for the determination of calcium and magnesium in a commercial spring water sample.

Large area x-ray detectors for cargo radiography

NASA Astrophysics Data System (ADS)

Bueno, C.; Albagli, D.; Bendahan, J.; Castleberry, D.; Gordon, C.; Hopkins, F.; Ross, W.

2007-04-01

Large area x-ray detectors based on phosphors coupled to flat panel amorphous silicon diode technology offer significant advances for cargo radiologic imaging. Flat panel area detectors provide large object coverage offering high throughput inspections to meet the high flow rate of container commerce. These detectors provide excellent spatial resolution when needed, and enhanced SNR through low noise electronics. If the resolution is reduced through pixel binning, further advances in SNR are achievable. Extended exposure imaging and frame averaging enables improved x-ray penetration of ultra-thick objects, or "select-your-own" contrast sensitivity at a rate many times faster than LDAs. The areal coverage of flat panel technology provides inherent volumetric imaging with the appropriate scanning methods. Flat panel area detectors have flexible designs in terms of electronic control, scintillator selection, pixel pitch, and frame rates. Their cost is becoming more competitive as production ramps up for the healthcare, nondestructive testing (NDT), and homeland protection industries. Typically used medical and industrial polycrystalline phosphor materials such as Gd2O2S:Tb (GOS) can be applied to megavolt applications if the phosphor layer is sufficiently thick to enhance x-ray absorption, and if a metal radiator is used to augment the quantum detection efficiency and reduce x-ray scatter. Phosphor layers ranging from 0.2-mm to 1-mm can be "sandwiched" between amorphous silicon flat panel diode arrays and metal radiators. Metal plates consisting of W, Pb or Cu, with thicknesses ranging from 0.25-mm to well over 1-mm can be used by covering the entire area of the phosphor plate. In some combinations of high density metal and phosphor layers, the metal plate provides an intensification of 25% in signal due to electron emission from the plate and subsequent excitation within the phosphor material. This further improves the SNR of the system.

Observing random walks of atoms in buffer gas through resonant light absorption

NASA Astrophysics Data System (ADS)

Aoki, Kenichiro; Mitsui, Takahisa

2016-07-01

Using resonant light absorption, random-walk motions of rubidium atoms in nitrogen buffer gas are observed directly. The transmitted light intensity through atomic vapor is measured, and its spectrum is obtained, down to orders of magnitude below the shot-noise level to detect fluctuations caused by atomic motions. To understand the measured spectra, the spectrum for atoms performing random walks in a Gaussian light beam is computed, and its analytical form is obtained. The spectrum has 1 /f2 (f is frequency) behavior at higher frequencies, crossing over to a different, but well-defined, behavior at lower frequencies. The properties of this theoretical spectrum agree excellently with the measured spectrum. This understanding also enables us to obtain the diffusion constant, the photon cross section of atoms in buffer gas, and the atomic number density from a single spectral measurement. We further discuss other possible applications of our experimental method and analysis.

Hydrogen detector

DOEpatents

Kanegae, Naomichi; Ikemoto, Ichiro

1980-01-01

A hydrogen detector of the type in which the interior of the detector is partitioned by a metal membrane into a fluid section and a vacuum section. Two units of the metal membrane are provided and vacuum pipes are provided independently in connection to the respective units of the metal membrane. One of the vacuum pipes is connected to a vacuum gauge for static equilibrium operation while the other vacuum pipe is connected to an ion pump or a set of an ion pump and a vacuum gauge both designed for dynamic equilibrium operation.

Development of a planar-type high sensitivity metallic contaminant detector

NASA Astrophysics Data System (ADS)

Okabe, Shunsuke; Sasada, Ichiro

2017-05-01

Metallic contaminant detectors based on the balanced coil system are widely used in the food industry. In the balanced coil system, an excitation coil and two identical pickup coils are used in a way that the magnetic coupling of pickup coils to the excitation coil is cancelled with each other when no metallic contaminants present. In a conventional system, the excitation coil and the pickup coil are planar and are parallel, therefore the magnetic coupling is strong even if there is no metallic contaminant. Such strong magnetic coupling makes balancing procedure tedious. In this paper, we introduce a new coil system in which pickup coils are set orthogonal to the excitation coil, making the magnetic coupling much small compared to conventional counterpart. Pickup coils are equipped with thin magnetic cores and placed inside the excitation coil being parallel to the excitation coil plane. The balancing method consists of two steps; the one is geometrical and the other is digital processing including down conversion. Experiments are carried out to show the detection capability of ferromagnetic contaminants and non-magnetic contaminants.

Metal artifact reduction for flat panel detector intravenous CT angiography in patients with intracranial metallic implants after endovascular and surgical treatment

PubMed Central

Pjontek, Rastislav; Önenköprülü, Belgin; Scholz, Bernhard; Kyriakou, Yiannis; Schubert, Gerrit A; Othman, Ahmed; Wiesmann, Martin; Brockmann, Marc A

2016-01-01

Background Flat panel detector CT angiography with intravenous contrast agent injection (IV CTA) allows high-resolution imaging of cerebrovascular structures. Artifacts caused by metallic implants like platinum coils or clips lead to degradation of image quality and are a significant problem. Objective To evaluate the influence of a prototype metal artifact reduction (MAR) algorithm on image quality in patients with intracranial metallic implants. Methods Flat panel detector CT after intravenous application of 80 mL contrast agent was performed with an angiography system (Artis zee; Siemens, Forchheim, Germany) using a 20 s rotation protocol (200° rotation angle, 20 s acquisition time, 496 projections). The data before and after MAR of 26 patients with a total of 34 implants (coils, clips, stents) were independently evaluated by two blinded neuroradiologists. Results MAR improved the assessability of the brain parenchyma and small vessels (diameter <1 mm) in the neighborhood of metallic implants and at a distance of 6 cm (p<0.001 each, Wilcoxon test). Furthermore, MAR significantly improved the assessability of parent vessel patency and potential aneurysm remnants (p<0.005 each, McNemar test). MAR, however, did not improve assessability of stented vessels. Conclusions When an intravenous contrast protocol is used, MAR significantly ameliorates the assessability of brain parenchyma, vessels, and treated aneurysms in patients with intracranial coils or clips. PMID:26346458

Through seniors' eyes: an exploratory qualitative study to identify environmental barriers to and facilitators of walking.

PubMed

Lockett, Donna; Willis, Alette; Edwards, Nancy

2005-09-01

This qualitative exploratory study examined environmental factors influencing the walking choices of elderly people using the photovoice approach. A total of 13 seniors in Ottawa, Canada, took photographs of barriers to and facilitators of walking in their neighbourhoods. These photos were displayed during 3 focus-group sessions and served as touchstones for discussion. A total of 22 seniors, including 8 of the 13 photographers, participated in the focus-group sessions. The findings show that environmental hazards related to traffic and falls risks can be significant barriers to walking for seniors, and that connectivity can truly exist for the elderly only if convenience, hazard-free routes are available. They also indicate that simple amenities such as benches and washrooms might facilitate walking for seniors. A neighbourhood that is activity-friendly for seniors will also be a good place for everyone else to live, work, and play. The use of photovoice as a method was well received by the participants and provided rich information that may not have been captured through other means.

Characterization of CdTe and (CdZn)Te detectors with different metal contacts

NASA Astrophysics Data System (ADS)

Pekárek, J.; Belas, E.; Grill, R.; Uxa, Å.; James, R. B.

2013-09-01

In the present work we studied an influence of different types of surface etching and surface passivation of high resistivity CdZnTe-based semiconductor detector material. The aim was to find the optimal conditions to improve the properties of metal-semiconductor contact. The main effort was to reduce the leakage current and thus get better X-ray and gamma-ray spectrum, i.e. to create a detector operating at room temperature based on this semiconductor material with sufficient energy resolution and the maximum charge collection efficiency. Individual surface treatments were characterized by I-V characteristics, spectral analysis and by determination of the profile of the internal electric field.

Increasing Walking in the Hartsfield-Jackson Atlanta International Airport: The Walk to Fly Study.

PubMed

Fulton, Janet E; Frederick, Ginny M; Paul, Prabasaj; Omura, John D; Carlson, Susan A; Dorn, Joan M

2017-07-01

To test the effectiveness of a point-of-decision intervention to prompt walking, versus motorized transport, in a large metropolitan airport. We installed point-of-decision prompt signage at 4 locations in the airport transportation mall at Hartsfield-Jackson Atlanta International Airport (Atlanta, GA) at the connecting corridor between airport concourses. Six ceiling-mounted infrared sensors counted travelers entering and exiting the study location. We collected traveler counts from June 2013 to May 2016 when construction was present and absent (preintervention period: June 2013-September 2014; postintervention period: September 2014-May 2016). We used a model that incorporated weekly walking variation to estimate the intervention effect on walking. There was an 11.0% to 16.7% relative increase in walking in the absence of airport construction where 580 to 810 more travelers per day chose to walk. Through May 2016, travelers completed 390 000 additional walking trips. The Walk to Fly study demonstrated a significant and sustained increase in the number of airport travelers choosing to walk. Providing signage about options to walk in busy locations where reasonable walking options are available may improve population levels of physical activity and therefore improve public health.

Modular multi-element high energy particle detector

DOEpatents

Coon, D.D.; Elliott, J.P.

1990-01-02

Multi-element high energy particle detector modules comprise a planar heavy metal carrier of tungsten alloy with planar detector units uniformly distributed over one planar surface. The detector units are secured to the heavy metal carrier by electrically conductive adhesive so that the carrier serves as a common ground. The other surface of each planar detector unit is electrically connected to a feedthrough electrical terminal extending through the carrier for front or rear readout. The feedthrough electrical terminals comprise sockets at one face of the carrier and mating pins projecting from the other face, so that any number of modules may be plugged together to create a stack of modules of any desired number of radiation lengths. The detector units each comprise four, preferably rectangular, p-i-n diode chips arranged around the associated feedthrough terminal to form a square detector unit providing at least 90% detector element coverage of the carrier. Integral spacers projecting from the carriers extend at least partially along the boundaries between detector units to space the p-i-n diode chips from adjacent carriers in a stack. The spacers along the perimeters of the modules are one-half the width of the interior spacers so that when stacks of modules are arranged side by side to form a large array of any size or shape, distribution of the detector units is uniform over the entire array. 5 figs.

Walking straight into circles.

PubMed

Souman, Jan L; Frissen, Ilja; Sreenivasa, Manish N; Ernst, Marc O

2009-09-29

Common belief has it that people who get lost in unfamiliar terrain often end up walking in circles. Although uncorroborated by empirical data, this belief has widely permeated popular culture. Here, we tested the ability of humans to walk on a straight course through unfamiliar terrain in two different environments: a large forest area and the Sahara desert. Walking trajectories of several hours were captured via global positioning system, showing that participants repeatedly walked in circles when they could not see the sun. Conversely, when the sun was visible, participants sometimes veered from a straight course but did not walk in circles. We tested various explanations for this walking behavior by assessing the ability of people to maintain a fixed course while blindfolded. Under these conditions, participants walked in often surprisingly small circles (diameter < 20 m), though rarely in a systematic direction. These results rule out a general explanation in terms of biomechanical asymmetries or other general biases [1-6]. Instead, they suggest that veering from a straight course is the result of accumulating noise in the sensorimotor system, which, without an external directional reference to recalibrate the subjective straight ahead, may cause people to walk in circles.

School Violence: Physical Security.

ERIC Educational Resources Information Center

Utah State Office of Education, Salt Lake City.

This booklet provides an overview of security technology product areas that might be appropriate and affordable for school applications. Topics cover security concepts and operational issues; security issues when designing for new schools; the role of maintenance; video camera use; walk-through metal detectors; duress alarm devices; and a partial…

Effect of carbon-composite knee-ankle-foot orthoses on walking efficiency and gait in former polio patients.

PubMed

Brehm, Merel-Anne; Beelen, Anita; Doorenbosch, Caroline A M; Harlaar, Jaap; Nollet, Frans

2007-10-01

To investigate the effects of total-contact fitted carbon-composite knee-ankle-foot orthoses (KAFOs) on energy cost of walking in patients with former polio who normally wear a conventional leather/metal KAFO or plastic/metal KAFO. A prospective uncontrolled study with a multiple baseline and follow-up design. Follow-up measurements continued until 26 weeks after intervention. Twenty adults with polio residuals (mean age 55 years). Each participant received a new carbon-composite KAFO, fitted according to a total-contact principle, which resulted in a rigid, lightweight and well-fitting KAFO. Energy cost of walking, walking speed, biomechanics of gait, physical functioning and patient satisfaction. The energy cost decreased significantly, by 8%, compared with the original KAFO. Furthermore, the incremention energy cost during walking with the carbon-composite KAFO was reduced by 18% towards normative values. An improvement in knee flexion, forward excursion of the centre of pressure, peak ankle moment, and timing of peak ankle power were significantly associated with the decrease in energy cost. Walking speed and physical functioning remained unchanged. In patients with former polio, carbon-composite KAFOs are superior to conventional leather/metal and plastic/metal KAFOs with respect to improving walking efficiency and gait, and are therefore important in reducing overuse and maintaining functional abilities in polio survivors.

Walking for Well-Being: Are Group Walks in Certain Types of Natural Environments Better for Well-Being than Group Walks in Urban Environments?

PubMed Central

Marselle, Melissa R.; Irvine, Katherine N.; Warber, Sara L.

2013-01-01

The benefits of walking in natural environments for well-being are increasingly understood. However, less well known are the impacts different types of natural environments have on psychological and emotional well-being. This cross-sectional study investigated whether group walks in specific types of natural environments were associated with greater psychological and emotional well-being compared to group walks in urban environments. Individuals who frequently attended a walking group once a week or more (n = 708) were surveyed on mental well-being (Warwick Edinburgh Mental Well-being Scale), depression (Major Depressive Inventory), perceived stress (Perceived Stress Scale) and emotional well-being (Positive and Negative Affect Schedule). Compared to group walks in urban environments, group walks in farmland were significantly associated with less perceived stress and negative affect, and greater mental well-being. Group walks in green corridors were significantly associated with less perceived stress and negative affect. There were no significant differences between the effect of any environment types on depression or positive affect. Outdoor walking group programs could be endorsed through “green prescriptions” to improve psychological and emotional well-being, as well as physical activity. PMID:24173142

Large volume flow-through scintillating detector

DOEpatents

Gritzo, Russ E.; Fowler, Malcolm M.

1995-01-01

A large volume flow through radiation detector for use in large air flow situations such as incinerator stacks or building air systems comprises a plurality of flat plates made of a scintillating material arranged parallel to the air flow. Each scintillating plate has a light guide attached which transfers light generated inside the scintillating plate to an associated photomultiplier tube. The output of the photomultiplier tubes are connected to electronics which can record any radiation and provide an alarm if appropriate for the application.

Separation of transition metals on a poly-iminodiacetic acid grafted polymeric resin column with post-column reaction detection utilising a paired emitter-detector diode system.

PubMed

Barron, Leon; O'Toole, Martina; Diamond, Dermot; Nesterenko, Pavel N; Paull, Brett

2008-12-05

The selectivity, retention and separation of transition metals on a short (2 mm x 50 mm) column packed with a poly-iminodiacetic acid functionalised polymer 10 microm resin (Dionex ProPac IMAC-10) are presented. This stationary phase, typically used for the separation of proteins, is composed of long chain poly-iminodiacetic acid groups grafted to a hydrophilic layer surrounding a 10 microm polymeric bead. Through the use of a combination of a multi-step pH and picolinic acid gradient, the separation of magnesium, iron, cobalt, cadmium, zinc, lead and copper was possible, followed by post-column reaction with 4-(2-pyridylazo) resorcinol (PAR) and absorbance detection at 510 nm using a novel and inexpensive optical detector, comprised of two light emitting diodes with one acting as a light source and the other as a detector. Column efficiency for selective transition metals was in excess of N=10,000, with the baseline separation of seven metal cations in <3 min possible under optimised conditions. Detection limits of between 5 and 81 microg/L were possible based upon a 50 microL injection volume.

Walk through screening with multistatic mmW technology

NASA Astrophysics Data System (ADS)

Gumbmann, Frank; Ahmed, Sherif Sayed

2016-10-01

Active imaging systems for security screening at the airport or other checkpoints have proven to offer good results. Present systems require a specific position and posture,13 or a specific movement2 of the passenger in front of the imaging system. Walk Through Systems (WTS) which screen the passenger while passing the imaging system or a screening hallway would be more pleasant for the passenger and would result in a great improvement in the throughput. Furthermore the detection performance could be enhanced since possible threats are visible from different perspectives and could be tracked within different frames. The combination of all frames is equivalent to a full illumination of the passenger. This paper presents the concept of a WTS basing on a multistatic imaging system in the mmW range. The benefit is that the technology of existing portals can we reused and updated to a WTS. First results are demonstrated with an experimental system.

Realization of deep 3D metal electrodes in diamond radiation detectors

NASA Astrophysics Data System (ADS)

Wulz, Thomas; Gerding, William; Lavrik, Nickolay; Briggs, Dayrl; Srijanto, Bernadeta; Lester, Kevin; Hensley, Dale; Spanier, Stefan; Lukosi, Eric

2018-05-01

A fabrication technique to create 3D diamond detectors is presented. Deep reactive ion etching was used to create an array of through-diamond vias (TDVs) in a 2 × 2 × 0.15 mm3 electronic grade single crystal diamond detector. The diameter of the TDVs was nominally 30 μm with a pitch of 100 μm between them. The TDVs were filled with chromium using hexavalent chromium electroplating to create 3D electrodes, which were connected electrically by interdigitated electrodes. The fabricated 3D diamond detector responded to both alpha particles and X-rays, exhibiting a charge collection efficiency of 52.3% at 200 V. Comparing to a diamond detector with the same interdigitated electrodes, but no 3D electrodes, confirms that the 3D electrodes are electrically active within the device. The average resistivity of the 3D electrodes is 2.89 ± 0.03 × 10-5 Ω cm, near that of bulk chromium. These results indicate that this fabrication technique is a potential option for 3D diamond detector fabrication.

Use of a Walk Through Time to Facilitate Student Understandings of the Geological Time Scale

NASA Astrophysics Data System (ADS)

Shipman, H. L.

2004-12-01

Students often have difficulties in appreciating just how old the earth and the universe are. While they can simply memorize a number, they really do not understand just how big that number really is, in comparison with other, more familiar student referents like the length of a human lifetime or how long it takes to eat a pizza. (See, e.g., R.D. Trend 2001, J. Research in Science Teaching 38(2): 191-221) Students, and members of the general public, also display such well-known misconceptions as the "Flintstone chronology" of believing that human beings and dinosaurs walked the earth at the same time. (In the classic American cartoon "The Flintstones," human beings used dinosaurs as draft animals. As scientists we know this is fiction, but not all members of the public understand that.) In an interdisciplinary undergraduate college class that dealt with astronomy, cosmology, and biological evolution, I used a familiar activity to try to improve student understanding of the concept of time's vastness. Students walked through a pre-determined 600-step path which provided a spatial analogy to the geological time scale. They stopped at various points and engaged in some pre-determined discussions and debates. This activity is as old as the hills, but reports of its effectiveness or lack thereof are quite scarce. This paper demonstrates that this activity was effective for a general-audience, college student population in the U.S. The growth of student understandings of the geological time scale was significant as a result of this activity. Students did develop an understanding of time's vastness and were able to articulate this understanding in various ways. This growth was monitored through keeping track of several exam questions and through pre- and post- analysis of student writings. In the pre-writings, students often stated that they had "no idea" about how to illustrate the size of the geological time scale to someone else. While some post-time walk responses

Detection of coins ingested by children using a handheld metal detector: a systematic review.

PubMed

Lee, J B; Ahmad, S; Gale, C P

2005-12-01

To determine if the use of a handheld metal detector (HHMD) can safely reduce the number of radiographs requested in cases of coins ingested by children, a search was performed to identify prospective studies of the ability of an HHMD to identify the presence or absence of ingested coin in children (17 years or younger). Outcome measures were presence or absence of coin on metal detector screening, and accuracy of coin localisation. Inclusion and exclusion criteria were defined. Mantel-Haenszel (fixed effect model) pooling with 95% confidence intervals (CI) was used to calculate overall sensitivities and specificities. In total, 11 studies met the inclusion criteria. The overall sensitivity of the HHMD at detecting the presence of coins was 99.4% (95% CI 98.0 to 99.9%) and accuracy at localisation was 99.8% (98.5 to 100.0%). The overall specificity of the HHMD was 100% (76.8 to 100%). Use of the HHMD is an accurate, radiation free, and cost effective method of identifying and localising coins ingested by children. An algorithm for investigating children with coin ingestion is proposed.

Metal artifact reduction for flat panel detector intravenous CT angiography in patients with intracranial metallic implants after endovascular and surgical treatment.

PubMed

Pjontek, Rastislav; Önenköprülü, Belgin; Scholz, Bernhard; Kyriakou, Yiannis; Schubert, Gerrit A; Nikoubashman, Omid; Othman, Ahmed; Wiesmann, Martin; Brockmann, Marc A

2016-08-01

Flat panel detector CT angiography with intravenous contrast agent injection (IV CTA) allows high-resolution imaging of cerebrovascular structures. Artifacts caused by metallic implants like platinum coils or clips lead to degradation of image quality and are a significant problem. To evaluate the influence of a prototype metal artifact reduction (MAR) algorithm on image quality in patients with intracranial metallic implants. Flat panel detector CT after intravenous application of 80 mL contrast agent was performed with an angiography system (Artis zee; Siemens, Forchheim, Germany) using a 20 s rotation protocol (200° rotation angle, 20 s acquisition time, 496 projections). The data before and after MAR of 26 patients with a total of 34 implants (coils, clips, stents) were independently evaluated by two blinded neuroradiologists. MAR improved the assessability of the brain parenchyma and small vessels (diameter <1 mm) in the neighborhood of metallic implants and at a distance of 6 cm (p<0.001 each, Wilcoxon test). Furthermore, MAR significantly improved the assessability of parent vessel patency and potential aneurysm remnants (p<0.005 each, McNemar test). MAR, however, did not improve assessability of stented vessels. When an intravenous contrast protocol is used, MAR significantly ameliorates the assessability of brain parenchyma, vessels, and treated aneurysms in patients with intracranial coils or clips. 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/

'It was not just a walking experience': reflections on the role of care in dog-walking.

PubMed

Degeling, Chris; Rock, Melanie

2013-09-01

Research into physical activity and human health has recently begun to attend to dog-walking. This study extends the literature on dog-walking as a health behaviour by conceptualizing dog-walking as a caring practice. It centres on qualitative interviews with 11 Canadian dog-owners. All participants resided in urban neighbourhoods identified through previous quantitative research as conducive to dog-walking. Canine characteristics, including breed and age, were found to influence people's physical activity. The health of the dog and its position in the life-course influenced patterns of dog-walking. Frequency, duration and spatial patterns of dog-walking all depended on relationships and people's capacity to tap into resources. In foregrounding networks of care, inclusive of pets and public spaces, a relational conceptualization of dog-walking as a practice of caring helps to make sense of heterogeneity in patterns of physical activity among dog-owners.

Idiopathic toe walking.

PubMed

Oetgen, Matthew E; Peden, Sean

2012-05-01

Toe walking is a bilateral gait abnormality in which a normal heel strike is absent and most weight bearing occurs through the forefoot. This abnormality may not be pathologic in patients aged <2 years, but it is a common reason for referral to an orthopaedic surgeon. Toe walking can be caused by several neurologic and developmental abnormalities and may be the first sign of a global developmental problem. Cases that lack a definitive etiology are categorized as idiopathic. A detailed history, with careful documentation of the developmental history, and a thorough physical examination are required in the child with a primary report of toe walking. Treatment is based on age and the severity of the abnormality. Management includes observation, stretching, casting, bracing, chemodenervation, and surgical lengthening of the gastrocnemius-soleus complex and/or Achilles tendon. An understanding of idiopathic toe walking as well as treatment options and their outcomes can help the physician individualize treatment to achieve optimal results.

Portable X-Ray, K-Edge Heavy Metal Detector

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

Fricke, V.

The X-Ray, K-Edge Heavy Metal Detection System was designed and built by Ames Laboratory and the Center for Nondestructive Evaluation at Iowa State University. The system uses a C-frame inspection head with an X-ray tube mounted on one side of the frame and an imaging unit and a high purity germanium detector on the other side. the inspection head is portable and can be easily positioned around ventilation ducts and pipes up to 36 inches in diameter. Wide angle and narrow beam X-ray shots are used to identify the type of holdup material and the amount of the contaminant. Precisemore » assay data can be obtained within minutes of the interrogation. A profile of the containerized holdup material and a permanent record of the measurement are immediately available.« less

[Walking abnormalities in children].

PubMed

Segawa, Masaya

2010-11-01

Walking is a spontaneous movement termed locomotion that is promoted by activation of antigravity muscles by serotonergic (5HT) neurons. Development of antigravity activity follows 3 developmental epochs of the sleep-wake (S-W) cycle and is modulated by particular 5HT neurons in each epoch. Activation of antigravity activities occurs in the first epoch (around the age of 3 to 4 months) as restriction of atonia in rapid eye movement (REM) stage and development of circadian S-W cycle. These activities strengthen in the second epoch, with modulation of day-time sleep and induction of crawling around the age of 8 months and induction of walking by 1 year. Around the age of 1 year 6 months, absence of guarded walking and interlimb cordination is observed along with modulation of day-time sleep to once in the afternoon. Bipedal walking in upright position occurs in the third epoch, with development of a biphasic S-W cycle by the age of 4-5 years. Patients with infantile autism (IA), Rett syndrome (RTT), or Tourette syndrome (TS) show failure in the development of the first, second, or third epoch, respectively. Patients with IA fail to develop interlimb coordination; those with RTT, crawling and walking; and those with TS, walking in upright posture. Basic pathophysiology underlying these condition is failure in restricting atonia in REM stage; this induces dysfunction of the pedunculopontine nucleus and consequently dys- or hypofunction of the dopamine (DA) neurons. DA hypofunction in the developing brain, associated with compensatory upward regulation of the DA receptors causes psychobehavioral disorders in infancy (IA), failure in synaptogenesis in the frontal cortex and functional development of the motor and associate cortexes in late infancy through the basal ganglia (RTT), and failure in functional development of the prefrontal cortex through the basal ganglia (TS). Further, locomotion failure in early childhood causes failure in development of functional

Development of a Miniaturized and Portable Methane Analyzer for Natural Gas Leak Walking Surveys

NASA Astrophysics Data System (ADS)

Huang, Y. W.; Leen, J. B.; Gupta, M.; Baer, D. S.

2016-12-01

Traditional natural gas leak walking surveys have been conducted with devices that are based on technologies such as flame ionization detector (FID), IR-based spectrometer and IR camera. The sensitivity is typically on the ppm level. The low sensitivity means the device cannot pick up leaks far from it, and more time is spent surveying the area before pinpointing the leak location. A miniaturized methane analyzer has been developed to significantly improve the sensitivity of the device used in walking surveys to detect natural gas leaks at greater distance. ABB/LGR's patented Off-Axis Integrated Cavity Output Spectroscopy (OA-ICOS) is utilized to offer rugged and highly sensitive methane detection in a portable package. The miniaturized package weighs 13.5 lb, with a 4-hour rechargeable battery inside. The precision of the analyzer for methane is 2 ppb at 1 second. The analyzer operates at 10 Hz and its flow response time is 3 seconds for measurements through a 1-meter long sampling wand to registering on the data stream. The data can be viewed in real-time on a tablet or a smartphone. The compact and simplified package of the methane analyzer allows for more efficient walking surveys. It also allows for other applications that require low-power, low-weight and a portable package. We present data from walking surveys to demonstrate its ability to detect methane leaks.

SOI metal-oxide-semiconductor field-effect transistor photon detector based on single-hole counting.

PubMed

Du, Wei; Inokawa, Hiroshi; Satoh, Hiroaki; Ono, Atsushi

2011-08-01

In this Letter, a scaled-down silicon-on-insulator (SOI) metal-oxide-semiconductor field-effect transistor (MOSFET) is characterized as a photon detector, where photogenerated individual holes are trapped below the negatively biased gate and modulate stepwise the electron current flowing in the bottom channel induced by the positive substrate bias. The output waveforms exhibit clear separation of current levels corresponding to different numbers of trapped holes. Considering this capability of single-hole counting, a small dark count of less than 0.02 s(-1) at room temperature, and low operation voltage of 1 V, SOI MOSFET could be a unique photon-number-resolving detector if the small quantum efficiency were improved. © 2011 Optical Society of America

Watermark Estimation through Detector Observations

DTIC Science & Technology

1998-03-01

electronic watermark detection is only feasible if the watermark detector is aware of the secret K. In many watermarking business scenarios the watermark...detector will be available to the public as a black box D. The following question is therefore justified: Can the secret K be deduced from the

Detector Apparatus and Method

NASA Technical Reports Server (NTRS)

Arndt, G. Dickey (Inventor); Ngo, Phong H. (Inventor); Carl, James R. (Inventor); Byerly, Kent A. (Inventor); Dusl, John (Inventor)

2003-01-01

Transceiver and methods are included that are especially suitable for detecting metallic materials, such as metallic mines, within an environment. The transceiver includes a digital waveform generator used to transmit a signal into the environment and a receiver that produces a digital received signal. A tracking module preferably compares an in-phase and quadrature transmitted signal with an in-phase and quadrature received signal to produce a spectral transfer function of the magnetic transceiver over a selected range of frequencies. The transceiver initially preferably creates a reference transfer function which is then stored in a memory. Subsequently measured transfer functions will vary depending on the presence of metal in the environment which was not in the environment when the reference transfer function was determined. The system may be utilized in the presence of other antennas, metal, and electronics which may comprise a plastic mine detector for detecting plastic mines. Despite the additional antennas and other metallic materials that may be in the environment due to the plastic mine detector, the magnetic transceiver remains highly sensitive to metallic material which may be located in various portions of the environment and which may be detected by sweeping the detector over ground that may contain metals or mines.

Development of a new scintillation-trigger detector for the MTV experiment using aluminum-metallized film tape

NASA Astrophysics Data System (ADS)

Sakamoto, Yuko; Ozaki, Sachi; Tanaka, Saki; Tanuma, Ryosuke; Yoshida, Tatsuru; Murata, Jiro

2014-09-01

A new type of trigger-scintillation counter array designed for the MTV experiment at TRIUMF-ISAC has been developed, using aluminum-metallized film tape for wrapping. The MTV experiment aims to perform the finest precision test of time reversal symmetry in nuclear beta decay. In that purpose, we search non-zero T-Violating transverse polarization of electrons emitted from polarized Li-8 nuclei. It uses a cylindrical drift chamber (CDC) as the main electron-tracking detector. The trigger-scintillation counter consists of 12-segmented 1 mm thick 300 mm long thin plastic scintillation counters. This counter is placed inside the CDC to generate a trigger signal. The required assembling precision of +-0.5 mm was a tricky point when we tried to use conventional total reflection mode. Indeed, produce an air-layer surrounding the scintillating bar to keep good light transmission was the main issue. For this reason, we tried to use a new wrapping material made of metallized-aluminum tape, which has a good mirror-like reflecting surface on both sides of the tape. Through this report, we will compare detection efficiency and light attenuation between conventional and new wrapping materials.

Gait Evaluation of Overground Walking and Treadmill Walking Using Compass-Type Walking Model

NASA Astrophysics Data System (ADS)

Nagata, Yousuke; Yamamoto, Masayoshi; Funabiki, Shigeyuki

A treadmill is a useful apparatus for the gait training and evaluation. However, many differences are reported between treadmill and overground walking. Experimental comparisons of the muscle activity of the leg and the heart rate have been carried out. However, the dynamic comparison has not been performed. The dynamic evaluation of the overground walking and the treadmill walking using a compass-type walking model (CTWM) which is a simple bipedal walking model, then their comparison is discussed. It is confirmed that the walking simulation using the CTWM can simulate the difference of that walk, it is clarified that there are the differences of the kick impulse on the ground and the turning impulse of the foot to the variation of the belt speed and then differences are the main factor of two walking.

Development of improved lithium tantalate pyroelectric detectors

NASA Technical Reports Server (NTRS)

Byer, N. E.; Vanderjagt, A.; Holton, W.

1978-01-01

A program was undertaken to increase the detectivity of LiTaO3 pyroelectric detectors to meet a performance requirement of D star (500 K, 15 Hz)=4x10 to the 9th power cm Hz1/2W-1. Emphasis was placed on reduction of the thermal conductance of the detector element to its surroundings, thinning the detector wafer to a thickness less than 3 micrometers, and increasing the absorptivity of the standard metallic film coatings. During the program, thermal conductance was reduced 41 percent through the use of reticulated (slotted) structures. Self-supported detector wafers less than 2 micrometers thick were fabricated. Multiple layer coatings, including an AR coating, with 16 percent more absorptance, were designed and fabricated. Later refinements in the multilayer design program have absorptivities of 75-80 percent, but detectors with these coatings had to be more than 2 micrometers thick because of a mismatch in the thermal expansion coefficients with LiTaO3.

Experiencing Nature through Immersive Virtual Environments: Environmental Perceptions, Physical Engagement, and Affective Responses during a Simulated Nature Walk

PubMed Central

Calogiuri, Giovanna; Litleskare, Sigbjørn; Fagerheim, Kaia A.; Rydgren, Tore L.; Brambilla, Elena; Thurston, Miranda

2018-01-01

By combining physical activity and exposure to nature, green exercise can provide additional health benefits compared to physical activity alone. Immersive Virtual Environments (IVE) have emerged as a potentially valuable supplement to environmental and behavioral research, and might also provide new approaches to green exercise promotion. However, it is unknown to what extent green exercise in IVE can provide psychophysiological responses similar to those experienced in real natural environments. In this study, 26 healthy adults underwent three experimental conditions: nature walk, sitting-IVE, and treadmill-IVE. The nature walk took place on a paved trail along a large river. In the IVE conditions, the participants wore a head-mounted display with headphones reproducing a 360° video and audio of the nature walk, either sitting on a chair or walking on a manually driven treadmill. Measurements included environmental perceptions (presence and perceived environmental restorativeness – PER), physical engagement (walking speed, heart rate, and perceived exertion), and affective responses (enjoyment and affect). Additionally, qualitative information was collected through open-ended questions. The participants rated the IVEs with satisfactory levels of ‘being there’ and ‘sense of reality,’ but also reported discomforts such as ‘flatness,’ ‘movement lag’ and ‘cyber sickness.’ With equivalent heart rate and walking speed, participants reported higher perceived exertion in the IVEs than in the nature walk. The nature walk was associated with high enjoyment and enhanced affect. However, despite equivalent ratings of PER in the nature walk and in the IVEs, the latter were perceived as less enjoyable and gave rise to a poorer affect. Presence and PER did not differ between the two IVEs, although in the treadmill-IVE the negative affective responses had slightly smaller magnitude than in the sitting-IVE. In both the IVEs, the negative affective responses

Rhythm Pattern of Sole through Electrification of the Human Body When Walking

NASA Astrophysics Data System (ADS)

Takiguchi, Kiyoaki; Wada, Takayuki; Tohyama, Shigeki

The rhythm of automatic cyclic movements such as walking is known to be generated by a rhythm generator called CPG in the spinal cord. The measurement of rhythm characteristics in walking is considered to be important for analyzing human bipedal walking and adaptive walking on irregular terrain. In particular, the soles that contact the terrain surface perform flexible movements similar to the movement of the fins of a lungfish, which is considered to be the predecessor of land animals. The sole movements are believed to be a basic movement acquired during prehistoric times. The detailed rhythm pattern of sole motion is considered to be important. We developed a method for measuring electrification without installing device on a subject's body and footwear for stabilizing the electrification of the human body. We measured the rhythm pattern of 20 subjects including 4 infants when walking by using this system and the corresponding equipment. Therefore, we confirmed the commonality of the correlative rhythm patterns of 20 subjects. Further, with regard to an individual subject, the reproducibility of a rhythm pattern with strong correlation coefficient > 0.93 ± 0.5 (mean ± SD) concerning rhythms of trials that are differently conducted on adult subjects could be confirmed.

Fuzzy logic based sensor performance evaluation of vehicle mounted metal detector systems

NASA Astrophysics Data System (ADS)

Abeynayake, Canicious; Tran, Minh D.

2015-05-01

Vehicle Mounted Metal Detector (VMMD) systems are widely used for detection of threat objects in humanitarian demining and military route clearance scenarios. Due to the diverse nature of such operational conditions, operational use of VMMD without a proper understanding of its capability boundaries may lead to heavy causalities. Multi-criteria fitness evaluations are crucial for determining capability boundaries of any sensor-based demining equipment. Evaluation of sensor based military equipment is a multi-disciplinary topic combining the efforts of researchers, operators, managers and commanders having different professional backgrounds and knowledge profiles. Information acquired through field tests usually involves uncertainty, vagueness and imprecision due to variations in test and evaluation conditions during a single test or series of tests. This report presents a fuzzy logic based methodology for experimental data analysis and performance evaluation of VMMD. This data evaluation methodology has been developed to evaluate sensor performance by consolidating expert knowledge with experimental data. A case study is presented by implementing the proposed data analysis framework in a VMMD evaluation scenario. The results of this analysis confirm accuracy, practicability and reliability of the fuzzy logic based sensor performance evaluation framework.

Solvable continuous-time random walk model of the motion of tracer particles through porous media.

PubMed

Fouxon, Itzhak; Holzner, Markus

2016-08-01

We consider the continuous-time random walk (CTRW) model of tracer motion in porous medium flows based on the experimentally determined distributions of pore velocity and pore size reported by Holzner et al. [M. Holzner et al., Phys. Rev. E 92, 013015 (2015)PLEEE81539-375510.1103/PhysRevE.92.013015]. The particle's passing through one channel is modeled as one step of the walk. The step (channel) length is random and the walker's velocity at consecutive steps of the walk is conserved with finite probability, mimicking that at the turning point there could be no abrupt change of velocity. We provide the Laplace transform of the characteristic function of the walker's position and reductions for different cases of independence of the CTRW's step duration τ, length l, and velocity v. We solve our model with independent l and v. The model incorporates different forms of the tail of the probability density of small velocities that vary with the model parameter α. Depending on that parameter, all types of anomalous diffusion can hold, from super- to subdiffusion. In a finite interval of α, ballistic behavior with logarithmic corrections holds, which was observed in a previously introduced CTRW model with independent l and τ. Universality of tracer diffusion in the porous medium is considered.

Calibrating cellular automaton models for pedestrians walking through corners

NASA Astrophysics Data System (ADS)

Dias, Charitha; Lovreglio, Ruggiero

2018-05-01

Cellular Automata (CA) based pedestrian simulation models have gained remarkable popularity as they are simpler and easier to implement compared to other microscopic modeling approaches. However, incorporating traditional floor field representations in CA models to simulate pedestrian corner navigation behavior could result in unrealistic behaviors. Even though several previous studies have attempted to enhance CA models to realistically simulate pedestrian maneuvers around bends, such modifications have not been calibrated or validated against empirical data. In this study, two static floor field (SFF) representations, namely 'discrete representation' and 'continuous representation', are calibrated for CA-models to represent pedestrians' walking behavior around 90° bends. Trajectory data collected through a controlled experiment are used to calibrate these model representations. Calibration results indicate that although both floor field representations can represent pedestrians' corner navigation behavior, the 'continuous' representation fits the data better. Output of this study could be beneficial for enhancing the reliability of existing CA-based models by representing pedestrians' corner navigation behaviors more realistically.

Walking groups for women with breast cancer: Mobilising therapeutic assemblages of walk, talk and place.

PubMed

Ireland, Aileen V; Finnegan-John, Jennifer; Hubbard, Gill; Scanlon, Karen; Kyle, Richard G

2018-03-08

Walking is widely accepted as a safe and effective method of promoting rehabilitation and a return to physical activity after a cancer diagnosis. Little research has considered the therapeutic qualities of landscape in relation to understanding women's recovery from breast cancer, and no study has considered the supportive and therapeutic benefits that walking groups might contribute to their wellbeing. Through a study of a volunteer-led walking group intervention for women living with and beyond breast cancer (Best Foot Forward) we address this gap. A mixed-methods design was used including questionnaires with walkers (n = 35) and walk leaders (n = 13); telephone interviews with walkers (n = 4) and walk leaders (n = 9); and walking interviews conducted outdoors and on the move with walkers (n = 15) and walk leaders (n = 4). Questionnaires were analysed descriptively. Interviews were audio-recorded, transcribed verbatim, and analysed thematically. Our study found that the combination of walking and talking enabled conversations to roam freely between topics and individuals, encouraging everyday and cancer-related conversation that created a form of 'shoulder-to-shoulder support' that might not occur in sedentary supportive care settings. Walking interviews pointed to three facets of the outdoor landscape - as un/natural, dis/placed and im/mobile - that walkers felt imbued it with therapeutic qualities. 'Shoulder-to-shoulder support' was therefore found to be contingent on the therapeutic assemblage of place, walk and talk. Thus, beyond the physical benefits that walking brings, it is the complex assemblage of walking and talking in combination with the fluid navigation between multiple spaces that mobilises a therapeutic assemblage that promotes wellbeing in people living with and beyond breast cancer. Copyright © 2018 Elsevier Ltd. All rights reserved.

On the electron density localization in elemental cubic ceramic and FCC transition metals by means of a localized electrons detector.

PubMed

Aray, Yosslen; Paredes, Ricardo; Álvarez, Luis Javier; Martiz, Alejandro

2017-06-14

The electron density localization in insulator and semiconductor elemental cubic materials with diamond structure, carbon, silicon, germanium, and tin, and good metallic conductors with face centered cubic structure such as α-Co, Ni, Cu, Rh, Pd, Ag, Ir, Pt, and Au, was studied using a localized electrons detector defined in the local moment representation. Our results clearly show an opposite pattern of the electron density localization for the cubic ceramic and transition metal materials. It was found that, for the elemental ceramic materials, the zone of low electron localization is very small and is mainly localized on the atomic basin edges. On the contrary, for the transition metals, there are low-valued localized electrons detector isocontours defining a zone of highly delocalized electrons that extends throughout the material. We have found that the best conductors are those in which the electron density at this low-value zone is the lowest.

Ultratrace detector for hand-held gas chromatography

DOEpatents

Andresen, Brian D.; Miller, Fred S.

1999-01-01

An ultratrace detector system for hand-held gas chromatography having high sensitivity, for example, to emissions generated during production of weapons, biological compounds, drugs, etc. The detector system is insensitive to water, air, helium, argon, oxygen, and C0.sub.2. The detector system is basically composed of a hand-held capillary gas chromatography (GC), an insulated heated redox-chamber, a detection chamber, and a vapor trap. For example, the detector system may use gas phase redox reactions and spectral absorption of mercury vapor. The gas chromatograph initially separates compounds that percolate through a bed of heated mercuric oxide (HgO) in a silica--or other metal--aerogel material which acts as an insulator. Compounds easily oxidized by HgO liberate atomic mercury that subsequently pass through a detection chamber which includes a detector cell, such as quartz, that is illuminated with a 254 nm ultra-violet (UV) mercury discharge lamp which generates the exact mercury absorption bands that are used to detect the liberated mercury atoms. Atomic mercury strongly absorbs 254 nm energy is therefore a specific signal for reducing compounds eluting from the capillary GC, whereafter the atomic mercury is trapped for example, in a silicon-aerogel trap.

The utility of a handheld metal detector in detection and localization of pediatric metallic foreign body ingestion.

PubMed

Nation, Javan; Jiang, Wen

2017-01-01

To test the ability of a handheld metal detector (HHMD) to identify the presence and location of ingested metallic foreign bodies (MFBs) in children. Prospective case series enrolling children suspected of metallic foreign body ingestion presenting to the Emergency Department. Thirty-eight children were enrolled and the HHMD was used to detect the presence and location of a MFB. Results were compared to standard radiographic studies. Thirty-seven of the 38 ingested foreign bodies were MFBs. Of the 37 MFBs, the HHMD positively identified 33, and 4 were missed by HHMD but identified on radiography. When positive, the location indicated by HHMD correlated 100% with radiograph. There were 33 true positives, 0 false positives, 4 false negatives, and 1 true negative. This resulted in a sensitivity of 89% (95% CI of 75%-96%) and specificity of 100% (95% CI of 2.5%-100%). Our study demonstrates the accuracy of HHMD in the identification and localization of metallic foreign bodies. We propose an emergency room foreign body protocol that uses HHMD as an early screening tool in triage in order to expedite the process of obtaining Otolaryngology consultation and potentially shorten the wait time to the operating room or discharge. In instances were outside films are previously performed, HHMD use may be able to minimize the overall radiation exposure to children by obviating the need for repeat radiographs. As the sensitivity is not 100%, a negative HHMD screening does not negate the need for a standard radiograph in order to avoid missed MFBs. HHMD is best suited for detection of coins, which accounts for the majority of the MFB ingestions, and may not be suitable for all metallic objects since the amount of metal may decrease its sensitivity. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Gamma ray detector modules

NASA Technical Reports Server (NTRS)

Capote, M. Albert (Inventor); Lenos, Howard A. (Inventor)

2009-01-01

A radiation detector assembly has a semiconductor detector array substrate of CdZnTe or CdTe, having a plurality of detector cell pads on a first surface thereof, the pads having a contact metallization and a solder barrier metallization. An interposer card has planar dimensions no larger than planar dimensions of the semiconductor detector array substrate, a plurality of interconnect pads on a first surface thereof, at least one readout semiconductor chip and at least one connector on a second surface thereof, each having planar dimensions no larger than the planar dimensions of the interposer card. Solder columns extend from contacts on the interposer first surface to the plurality of pads on the semiconductor detector array substrate first surface, the solder columns having at least one solder having a melting point or liquidus less than 120 degrees C. An encapsulant is disposed between the interposer circuit card first surface and the semiconductor detector array substrate first surface, encapsulating the solder columns, the encapsulant curing at a temperature no greater than 120 degrees C.

"You've got to walk before you run": positive evaluations of a walking program as part of a gender-sensitized, weight-management program delivered to men through professional football clubs.

PubMed

Hunt, Kate; McCann, Claire; Gray, Cindy M; Mutrie, Nanette; Wyke, Sally

2013-01-01

To explore men's views of a pedometer-based walking program, part of a weight-management intervention delivered through Scottish Premier League football clubs, and the congruence or challenge this poses to masculine identities. Semistructured telephone interviews with a sample of participants in a gender-sensitized, group weight-management program. Interviewing continued until data saturation was reached (n = 29). All men were positive about the context, style of delivery, and content of the broader intervention. These things encouraged men to increase their physical activity (and adopt other behavioral changes) that they may not otherwise have found appealing. The success and acceptability of the walking program resided in three interrelated factors: (a) the utility of pedometers as a technology for motivation, self-monitoring and surveillance, and target setting; (b) the speed with which fitness was regained and weight reduced (enabling men to begin to do more desired forms of physical activity, and so regain visceral, experiential, and pragmatic masculine capital); and (c) bolstering their masculine identities through the receipt of the program in a valued, masculinised context. These data suggest that men will enthusiastically embrace a graduated walking program when the presentation is gender sensitive in context, content, and delivery. Pedometers were viewed as a valuable, reliable technological aid which motivated men and empowered them in self-monitoring of progress toward self-defined goals. Many men experienced the walking program as a means of regaining fitness, thereby enabling them to also regain valued masculine identities and activities, and a step toward regaining a more acceptable masculine body. PsycINFO Database Record (c) 2013 APA, all rights reserved.

After Talking the Talk, Now Walk the Walk

ERIC Educational Resources Information Center

Vukovic, Paul

2011-01-01

In this article, the author describes what his students are doing following the ATM Easter conference in Telford, where he was inspired by a workshop entitled "Vitamin D Maths," conducted by Jocelyn D'Arcy. He describes an activity that allows his Year 11 students to walk through angles drawn on the floors. This topic will now literally…

Relation between random walks and quantum walks

NASA Astrophysics Data System (ADS)

Boettcher, Stefan; Falkner, Stefan; Portugal, Renato

2015-05-01

Based on studies of four specific networks, we conjecture a general relation between the walk dimensions dw of discrete-time random walks and quantum walks with the (self-inverse) Grover coin. In each case, we find that dw of the quantum walk takes on exactly half the value found for the classical random walk on the same geometry. Since walks on homogeneous lattices satisfy this relation trivially, our results for heterogeneous networks suggest that such a relation holds irrespective of whether translational invariance is maintained or not. To develop our results, we extend the renormalization-group analysis (RG) of the stochastic master equation to one with a unitary propagator. As in the classical case, the solution ρ (x ,t ) in space and time of this quantum-walk equation exhibits a scaling collapse for a variable xdw/t in the weak limit, which defines dw and illuminates fundamental aspects of the walk dynamics, e.g., its mean-square displacement. We confirm the collapse for ρ (x ,t ) in each case with extensive numerical simulation. The exact values for dw themselves demonstrate that RG is a powerful complementary approach to study the asymptotics of quantum walks that weak-limit theorems have not been able to access, such as for systems lacking translational symmetries beyond simple trees.

41 CFR 109-45.1004 - Recovery and use of precious metals through the DOD Precious Metals Recovery Program.

Code of Federal Regulations, 2011 CFR

2011-01-01

... precious metals through the DOD Precious Metals Recovery Program. 109-45.1004 Section 109-45.1004 Public... PERSONAL PROPERTY 45.10-Recovery of Precious Metals § 109-45.1004 Recovery and use of precious metals through the DOD Precious Metals Recovery Program. DOE operates its own precious metals pool and therefore...

41 CFR 109-45.1004 - Recovery and use of precious metals through the DOD Precious Metals Recovery Program.

Code of Federal Regulations, 2010 CFR

2010-07-01

... precious metals through the DOD Precious Metals Recovery Program. 109-45.1004 Section 109-45.1004 Public... PERSONAL PROPERTY 45.10-Recovery of Precious Metals § 109-45.1004 Recovery and use of precious metals through the DOD Precious Metals Recovery Program. DOE operates its own precious metals pool and therefore...

Extraordinary light transmission through opaque thin metal film with subwavelength holes blocked by metal disks.

PubMed

Li, Wen-Di; Hu, Jonathan; Chou, Stephen Y

2011-10-10

We observed that when subwavelength-sized holes in an optically opaque metal film are completely covered by opaque metal disks larger than the holes, the light transmission through the holes is not reduced, but rather enhanced. Particularly we report (i) the observation of light transmission through the holes blocked by the metal disks up to 70% larger than the unblocked holes; (ii) the observation of tuning the light transmission by varying the coupling strength between the blocking disks and the hole array, or by changing the size of the disks and holes; (iii) the observation and simulation that the metal disk blocker can improve light coupling from free space to a subwavelength hole; and (iv) the simulation that shows the light transmission through subwavelength holes can be enhanced, even though the gap between the disk and the metal film is partially connected with a metal. We believe these finding should have broad and significant impacts and applications to optical systems in many fields.

Construction of a low-cost detector to identify dissolved metals in aqueous media by fluorescence spectroscopy: design and perspectives.

NASA Astrophysics Data System (ADS)

González, M.; Montaño, M.; Hoyo, C.

2017-01-01

We have constructed a low cost fluorescence detector model to determine the presence of some heavy metals in an aqueous medium. In particular, we focus on metals which cause public health problems in our country. We did the first tests with standard samples of Hg (II). The innovative features of this instrument are its small dimensions (9 dm3) and the low cost of materials used in its construction.

Ultra-thin enhanced-absorption long-wave infrared detectors

NASA Astrophysics Data System (ADS)

Wang, Shaohua; Yoon, Narae; Kamboj, Abhilasha; Petluru, Priyanka; Zheng, Wanhua; Wasserman, Daniel

2018-02-01

We propose an architecture for enhanced absorption in ultra-thin strained layer superlattice detectors utilizing a hybrid optical cavity design. Our detector architecture utilizes a designer-metal doped semiconductor ground plane beneath the ultra-subwavelength thickness long-wavelength infrared absorber material, upon which we pattern metallic antenna structures. We demonstrate the potential for near 50% detector absorption in absorber layers with thicknesses of approximately λ0/50, using realistic material parameters. We investigate detector absorption as a function of wavelength and incidence angle, as well as detector geometry. The proposed device architecture offers the potential for high efficiency detectors with minimal growth costs and relaxed design parameters.

Walk Score, Transportation Mode Choice, and Walking Among French Adults: A GPS, Accelerometer, and Mobility Survey Study.

PubMed

Duncan, Dustin T; Méline, Julie; Kestens, Yan; Day, Kristen; Elbel, Brian; Trasande, Leonardo; Chaix, Basile

2016-06-20

among adults in Paris, as documented at the trip level. Creating walkable neighborhoods (through neighborhood design increased commercial activity) may increase walking trips and, therefore, could be a relevant health promotion strategy to increase physical activity.

Walk Score, Transportation Mode Choice, and Walking Among French Adults: A GPS, Accelerometer, and Mobility Survey Study

PubMed Central

Duncan, Dustin T.; Méline, Julie; Kestens, Yan; Day, Kristen; Elbel, Brian; Trasande, Leonardo; Chaix, Basile

2016-01-01

neighborhoods were associated with increases in walking among adults in Paris, as documented at the trip level. Creating walkable neighborhoods (through neighborhood design increased commercial activity) may increase walking trips and, therefore, could be a relevant health promotion strategy to increase physical activity. PMID:27331818

Fire-Walking

ERIC Educational Resources Information Center

Willey, David

2010-01-01

This article gives a brief history of fire-walking and then deals with the physics behind fire-walking. The author has performed approximately 50 fire-walks, took the data for the world's hottest fire-walk and was, at one time, a world record holder for the longest fire-walk (www.dwilley.com/HDATLTW/Record_Making_Firewalks.html). He currently…

Walking to health.

PubMed

Morris, J N; Hardman, A E

1997-05-01

Walking is a rhythmic, dynamic, aerobic activity of large skeletal muscles that confers the multifarious benefits of this with minimal adverse effects. Walking, faster than customary, and regularly in sufficient quantity into the 'training zone' of over 70% of maximal heart rate, develops and sustains physical fitness: the cardiovascular capacity and endurance (stamina) for bodily work and movement in everyday life that also provides reserves for meeting exceptional demands. Muscles of the legs, limb girdle and lower trunk are strengthened and the flexibility of their cardinal joints preserved; posture and carriage may improve. Any amount of walking, and at any pace, expends energy. Hence the potential, long term, of walking for weight control. Dynamic aerobic exercise, as in walking, enhances a multitude of bodily processes that are inherent in skeletal muscle activity, including the metabolism of high density lipoproteins and insulin/glucose dynamics. Walking is also the most common weight-bearing activity, and there are indications at all ages of an increase in related bone strength. The pleasurable and therapeutic, psychological and social dimensions of walking, whilst evident, have been surprisingly little studied. Nor has an economic assessment of the benefits and costs of walking been attempted. Walking is beneficial through engendering improved fitness and/or greater physiological activity and energy turnover. Two main modes of such action are distinguished as: (i) acute, short term effects of the exercise; and (ii) chronic, cumulative adaptations depending on habitual activity over weeks and months. Walking is often included in studies of exercise in relation to disease but it has seldom been specifically tested. There is, nevertheless, growing evidence of gains in the prevention of heart attack and reduction of total death rates, in the treatment of hypertension, intermittent claudication and musculoskeletal disorders, and in rehabilitation after heart

Direct metal writing: Controlling the rheology through microstructure

DOE PAGES

Chen, Wen; Thornley, Luke; Coe, Hannah G.; ...

2017-02-27

Most metal additive manufacturing approaches are based on powder-bed melting techniques such as laser selective melting or electron beam melting, which often yield uncontrolled microstructures with defects (e.g., pores or microcracks) and residual stresses. Here, we introduce a proof-of-concept prototype of a 3D metal freeform fabrication process by direct writing of metallic alloys in the semi-solid regime. This process is achieved through controlling the particular microstructure and the rheological behavior of semi-solid alloy slurries, which demonstrate a well suited viscosity and a shear thinning property to retain the shape upon printing. Furthermore, the ability to control the microstructure through thismore » method yields a flexible manufacturing route to fabricating 3D metal parts with full density and complex geometries.« less

Direct metal writing: Controlling the rheology through microstructure

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

Chen, Wen; Thornley, Luke; Coe, Hannah G.

Most metal additive manufacturing approaches are based on powder-bed melting techniques such as laser selective melting or electron beam melting, which often yield uncontrolled microstructures with defects (e.g., pores or microcracks) and residual stresses. Here, we introduce a proof-of-concept prototype of a 3D metal freeform fabrication process by direct writing of metallic alloys in the semi-solid regime. This process is achieved through controlling the particular microstructure and the rheological behavior of semi-solid alloy slurries, which demonstrate a well suited viscosity and a shear thinning property to retain the shape upon printing. Furthermore, the ability to control the microstructure through thismore » method yields a flexible manufacturing route to fabricating 3D metal parts with full density and complex geometries.« less

Walking Children Through a Minefield: How Professionals Experience Exploring Adverse Childhood Experiences

PubMed Central

Albaek, Ane U.; Kinn, Liv G.; Milde, Anne M.

2017-01-01

Understanding the challenges of professionals in addressing child adversity is key to improving the detection, protection, and care of exposed children. We aimed to synthesize findings from qualitative studies of professionals’ lived experience of addressing child adversity. Through a systematic search, we identified eight qualitative studies and synthesized them using metaethnography. We generated three themes, “feeling inadequate,” “fear of making it worse,” and “facing evil,” and one overarching metaphor, “walking children through a minefield.” The professionals felt that they lacked the means necessary to explore child adversity, that they were apprehensive of worsening the child’s situation, and that their work with child adversity induced emotional discomfort. This metasynthesis indicated that the professionals’ efficiency in exploring abuse relied upon their ability to manage emotional and moral distress and complexity. To support children at risk, we propose developing professionals’ ability to build relationships, skills in emotion regulation, and proficiency in reflective practice. PMID:29046119

Spin lattices of walking droplets

NASA Astrophysics Data System (ADS)

Saenz, Pedro; Pucci, Giuseppe; Goujon, Alexis; Dunkel, Jorn; Bush, John

2017-11-01

We present the results of an experimental investigation of the spontaneous emergence of collective behavior in spin lattice of droplets walking on a vibrating fluid bath. The bottom topography consists of relatively deep circular wells that encourage the walking droplets to follow circular trajectories centered at the lattice sites, in one direction or the other. Wave-mediated interactions between neighboring drops are enabled through a thin fluid layer between the wells. The sense of rotation of the walking droplets may thus become globally coupled. When the coupling is sufficiently strong, interactions with neighboring droplets may result in switches in spin that lead to preferred global arrangements, including correlated (all drops rotating in the same direction) or anti-correlated (neighboring drops rotating in opposite directions) states. Analogies with ferromagnetism and anti-ferromagnetism are drawn. Different spatial arrangements are presented in 1D and 2D lattices to illustrate the effects of topological frustration. This work was supported by the US National Science Foundation through Grants CMMI-1333242 and DMS-1614043.

Application of Mythen detector: In-situ XRD study on the thermal expansion behavior of metal indium

NASA Astrophysics Data System (ADS)

Du, Rong; Chen, ZhongJun; Cai, Quan; Fu, JianLong; Gong, Yu; Wu, ZhongHua

2016-07-01

A Mythen detector has been equipped at the beamline 4B9A of Beijing Synchrotron Radiation Facility (BSRF), which is expected to enable BSRF to perform time-resolved measurement of X-ray diffraction (XRD) full-profiles. In this paper, the thermal expansion behavior of metal indium has been studied by using the in-situ XRD technique with the Mythen detector. The indium was heated from 303 to 433 K with a heating rate of 2 K/min. The in-situ XRD full-profiles were collected with a rate of one profile per 10 seconds. Rietveld refinement was used to extract the structural parameters. The results demonstrate that these collected quasi-real-time XRD profiles can be well used for structural analysis. The metal indium was found to have a nonlinear thermal expansion behavior from room temperature to the melting point (429.65 K). The a-axis of the tetragonal unit cell expands with a biquadratic dependency on temperature, while the c-axis contracts with a cubic dependency on temperature. By the time-resolved XRD measurements, it was observed that the [200] preferred orientation can maintain to about 403.15 K. While (110) is the last and detectable crystal plane just before melting of the polycrystalline indium foil. This study is not only beneficial to the application of metal indium, but also exhibits the capacity of in-situ time-resolved XRD measurements at the X-ray diffraction station of BSRF.

Walk Score(TM), Perceived Neighborhood Walkability, and walking in the US.

PubMed

Tuckel, Peter; Milczarski, William

2015-03-01

To investigate both the Walk Score(TM) and a self-reported measure of neighborhood walkability ("Perceived Neighborhood Walkability") as estimators of transport and recreational walking among Americans. The study is based upon a survey of a nationally-representative sample of 1224 American adults. The survey gauged walking for both transport and recreation and included a self-reported measure of neighborhood walkability and each respondent's Walk Score(TM). Binary logistic and linear regression analyses were performed on the data. The Walk Score(TM) is associated with walking for transport, but not recreational walking nor total walking. Perceived Neighborhood Walkability is associated with transport, recreational and total walking. Perceived Neighborhood Walkability captures the experiential nature of walking more than the Walk Score(TM).

Evaluation of functional capacity for exercise in children and adolescents with sickle-cell disease through the six-minute walk test.

PubMed

Hostyn, Sandro V; Carvalho, Werther B de; Johnston, Cíntia; Braga, Josefina A P

2013-01-01

To evaluate lung functional capacity (FC) for physical exercise in children and adolescents with sickle cell disease (SCD) through the six-minute walk test (6MWT). A cross-sectional prospective study was performed to evaluate the FC of 46 patients with SCD through the 6MWT. The following parameters were assessed: heart rate (HR), respiratory rate (RR), peripheral pulse oxygen saturation (SpO2), peak expiratory flow (PEF), blood pressure (systolic and diastolic), dyspnea, and leg fatigue (modified Borg scale) at rest, in the end of the test, and ten minutes after the 6MWT. The total distance walked was also recorded. For statistical analysis, the parametric variables were analyzed using the paired Student's t-test, analysis of variance (ANOVA), and Bonferroni multiple comparisons, with a significance level set at p ≤ 0.05. The 46 patients were aged age 9.15±3.06 years, presented baseline Hb of 9.49±1.67g/dL, and walked 480.89±68.70 m. SCD diagnosis was as follows: group 1- HbSS (n=20)/HbSβ(0)-thalassemia (n=3) and group 2 - HbSC (n=20)/HbSβ(+)-thalassemia (n=3). Regarding total distance walked, patients in group 1 walked a shorter distance than patients in group 2 (459.39±57.19 vs. 502.39±73.60 m; p=0.032). There was no statistical difference regarding PEF in the three moments of evaluation. The SpO2 in ambient air and SpO2 with O2 differed between groups 1 and 2 (p<0.001 vs. p=0.002), as well as the RR (p=0.001). These patients showed a lower FC for exercise than that predicted for the age range in the literature. Patients diagnosed with HbSS/Sβ0-thalassemia had a lower performance in the test than those with HbSC/Sβ(+)-thalassemia regarding total distance walked, RR, and SpO2 after the 6MWT. Copyright © 2013 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

Perception, planning, and control for walking on rugged terrain

NASA Technical Reports Server (NTRS)

Simmons, Reid; Krotkov, Eric

1991-01-01

The CMU Planetary Rover project is developing a six-legged walking robot capable of autonomously navigating, exploring, and acquiring samples in rugged, unknown environments. To gain experience with the problems involved in walking on rugged terrain, a full-scale prototype leg was built and mounted on a carriage that rolls along overhead rails. Issues addressed in developing the software system to autonomously walk the leg through rugged terrain are described. In particular, the insights gained into perceiving and modeling rugged terrain, controlling the legged mechanism, interacting with the ground, choosing safe yet effective footfalls, and planning efficient leg moves through space are described.

Age-related impairments of mobility associated with cobalt and other heavy metals: Data from NHANES 1999-2004

PubMed Central

Lang, Iain A; Scarlett, Alan; Guralnik, Jack; Depledge, Michael H; Melzer, David; Galloway, Tamara S

2012-01-01

Introduction Exposure to heavy metals can promote oxidative stress and damage to cellular components, and may accelerate age-related disease and disability.. Physical mobility is a validated biomarker of age-related disability and is predictive of hospitalization and mortality. Aim To examine associations between selected heavy metals and impaired lower limb mobility in a representative older human population. Methods Data for 1615 adults aged ≥60 years from the National Health and Nutrition Examination Survey (NHANES) 1999 to 2004 were used to identify associations between urinary concentrations of 10 metals with self-reported and measured walking impairments (at p<0.01). Models were adjusted for confounding factors, including smoking. Results In models adjusted for age, sex and ethnicity, elevated levels of cadmium, cobalt and uranium were associated with impairment of the ability to walk a quarter mile. In fully adjusted models, cobalt was the only metal that remained associated: the odds ratio for reporting walking problems with a 1-unit increase in logged cobalt concentration (μg L-1) was 1.43 (95% CI 1.12 to 1.84). Cobalt was also the only metal associated with an increased measured time to walk a 20 foot course (p=0.008). In analyses of disease categories to explain the mobility finding, cobalt was associated with physician diagnosed arthritis (1-unit increase OR=1.22 (95% CI 1.00 to 1.49, p=0.045). Conclusions Low level cobalt exposure, assessed through urinary concentrations of this essential heavy metal may be a risk factor for age-related physical impairments. Independent replication is needed to confirm this association. PMID:19199147

Metal detector system

NASA Technical Reports Server (NTRS)

Lee, R. D.

1970-01-01

Signal voltage resulting from the disturbance of an electromagnetic field within the volume of a sensitive area is compared with a reference ac voltage for polarity information, which identifies the material. System output amplitude and polarity indicate approximate size and type of metal, respectively.

Who walks? Factors associated with walking behavior in disabled older women with and without self-reported walking difficulty.

PubMed

Simonsick, E M; Guralnik, J M; Fried, L P

1999-06-01

To determine how severity of walking difficulty and sociodemographic, psychosocial, and health-related factors influence walking behavior in disabled older women. Cross-sectional analyses of baseline data from the Women's Health and Aging Study (WHAS). An urban community encompassing 12 contiguous zip code areas in the eastern portion of Baltimore City and part of Baltimore County, Maryland. A total of 920 moderately to severely disabled community-resident women, aged 65 years and older, identified from an age-stratified random sample of Medicare beneficiaries. Walking behavior was defined as minutes walked for exercise and total blocks walked per week. Independent variables included self-reported walking difficulty, sociodemographic factors, psychological status (depression, mastery, anxiety, and cognition), and health-related factors (falls and fear of falling, fatigue, vision and balance problems, weight, smoking, and cane use). Walking at least 8 blocks per week was strongly negatively related to severity of walking difficulty. Independent of difficulty level, older age, black race, fatigue, obesity, and cane use were also negatively associated with walking; living alone and high mastery had a positive association with walking. Even among functionally limited women, sociocultural, psychological, and health-related factors were independently associated with walking behavior. Thus, programs aimed at improving walking ability need to address these factors in addition to walking difficulties to maximize participation and compliance.

On the physical realizability of quantum stochastic walks

NASA Astrophysics Data System (ADS)

Taketani, Bruno; Govia, Luke; Schuhmacher, Peter; Wilhelm, Frank

Quantum walks are a promising framework that can be used to both understand and implement quantum information processing tasks. The recently developed quantum stochastic walk combines the concepts of a quantum walk and a classical random walk through open system evolution of a quantum system, and have been shown to have applications in as far reaching fields as artificial intelligence. However, nature puts significant constraints on the kind of open system evolutions that can be realized in a physical experiment. In this work, we discuss the restrictions on the allowed open system evolution, and the physical assumptions underpinning them. We then introduce a way to circumvent some of these restrictions, and simulate a more general quantum stochastic walk on a quantum computer, using a technique we call quantum trajectories on a quantum computer. We finally describe a circuit QED approach to implement discrete time quantum stochastic walks.

To walk or not to walk: insights from a qualitative description study with women suffering from fibromyalgia.

PubMed

Sanz-Baños, Yolanda; Pastor, María-Ángeles; Velasco, Lilian; López-Roig, Sofía; Peñacoba, Cecilia; Lledo, Ana; Rodríguez, Charo

2016-08-01

Walking improves health outcomes in fibromyalgia; however, there is low adherence to this practice. The aim of this research was to explore the beliefs of women suffering from fibromyalgia toward walking, and the meaning that they attribute to the behavior of walking as part of their fibromyalgia treatment. This study is a qualitative description research. Forty-six (46) women suffering from fibromyalgia and associated with local fibromyalgia associations located in four different Spanish cities (Elche, Alicante, Madrid, and Talavera de la Reina) participated in focus group discussions in the summer 2012. Thematic content analysis was performed in transcribed verbatim from interviews. Participants perceived several inhibitors for walking even when they had positive beliefs toward its therapeutic value. Whereas participants believed that walking can generate improvement in their disease and their health in general, they did not feel able to actually do so given their many physical impediments. Furthermore, participants struggled with social isolation and stigma, which was lessened through the conscious support of family. Advice from family doctors was also a very important facilitator to participants. In a health care delivery context that favors person-centered care, and in order to foster adherence to walking-based fibromyalgia treatments, it is recommended that therapeutic walking programs be tailored to each woman' individual circumstances, and developed in close collaboration with them to help them increase control over their health and their condition.

Modeling blur in various detector geometries for MeV radiography

NASA Astrophysics Data System (ADS)

Winch, Nicola M.; Watson, Scott A.; Hunter, James F.

2017-03-01

Monte Carlo transport codes have been used to model the detector blur and energy deposition in various detector geometries for applications in MeV radiography. Segmented scintillating detectors, where low Z scintillators combined with a high-Z metal matrix, can be designed in which the resolution increases with increasing metal fraction. The combination of various types of metal intensification screens and storage phosphor imaging plates has also been studied. A storage phosphor coated directly onto a metal intensification screen has superior performance over a commercial plate. Stacks of storage phosphor plates and tantalum intensification screens show an increase in energy deposited and detective quantum efficiency with increasing plate number, at the expense of resolution. Select detector geometries were tested by comparing simulation and experimental modulation transfer functions to validate the approach.

Physical realizability of continuous-time quantum stochastic walks

NASA Astrophysics Data System (ADS)

Taketani, Bruno G.; Govia, Luke C. G.; Wilhelm, Frank K.

2018-05-01

Quantum walks are a promising methodology that can be used to both understand and implement quantum information processing tasks. The quantum stochastic walk is a recently developed framework that combines the concept of a quantum walk with that of a classical random walk, through open system evolution of a quantum system. Quantum stochastic walks have been shown to have applications in as far reaching fields as artificial intelligence. However, there are significant constraints on the kind of open system evolutions that can be realized in a physical experiment. In this work, we discuss the restrictions on the allowed open system evolution and the physical assumptions underpinning them. We show that general direct implementations would require the complete solution of the underlying unitary dynamics and sophisticated reservoir engineering, thus weakening the benefits of experimental implementation.

Ionic Transport Through Metal-Rich Organic Coatings

DTIC Science & Technology

2016-08-19

COVERED October 2013-Septermber 2015 4. TITLE AND SUBTITLE Ionic Transport Through Metal-Rich Organic Coatings 5a. CONTRACT NUMBER 5b. GRANT...NOTES 14. ABSTRACT Organic coatings are commonly used on aircraft and in the automotive industry to protect against corrosive environments. Although...volume (MPV) percent, solvent polarity, and resin molecular weight impact corrosion protection of metal-rich organic (MRO) coatings. Following design

Ionic Transport Through Metal-Rich Organic Coatings

DTIC Science & Technology

2016-08-19

COVERED October 2013-Septermber 2015 4. TITLE AND SUBTITLE Ionic Transport Through Metal-Rich Organic Coatings 5a. CONTRACT NUMBER 5b. GRANT...14. ABSTRACT Organic coatings are commonly used on aircraft and in the automotive industry to protect against corrosive environments. Although...volume (MPV) percent, solvent polarity, and resin molecular weight impact corrosion protection of metal-rich organic (MRO) coatings. Following design of

Human pair walking behavior: evaluation of cooperation strategies

NASA Astrophysics Data System (ADS)

Dobramysl, Ulrich; Bodova, Katarina; Kollar, Richard; Erban, Radek

2015-03-01

Human walkers are notoriously poor at keeping a direction without external cues: Experimental work by Souman et al. with blindfolded subjects told to walk in a straight line revealed intriguing circular and spiraling trajectories, which can be approximated by a stochastic process. In this work, motivated by pair walking experiments by Miglierini et al., we introduce an analysis of various strategies employed by a pair of blindfolded walkers, who are communicating via auditory cues, to maximize their efficiency at walking straight. To this end, we characterize pairs of strategies such as free walking, side-by-side walking and unconditional following from data generated by robot pair walking experiments (using computer vision techniques) and numerical simulations. We extract the mean exit distances of walker pairs from a corridor with finite width to construct phase portraits of the walking performance. We find intriguing cooperative effects leading to non-trivial enhancements of the efficiency at walking straight. The research leading to these results has received funding from the European Research Council under the European Community's Seventh Framework Programme (FP7/2007-2013) / ERC Grant Agreement No. 239870; and from the Royal Society through a Research Grant.

Walk-through survey report: Control of methylene chloride in furniture stripping at jet strip, Boulder, Colorado, August 1, 1991

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

Hall, R.M.; Sheehy, J.W.

1992-12-01

A walk through survey was made of the furniture stripping process at Jet Strip (SIC-7641), Boulder, Colorado to examine the effectiveness of a unique, enclosed, automated furniture stripping spray system which featured a gasket sealed lid which was in place while furniture was being stripped. Stripping was performed continuously throughout the workday. The enclosed spray system tank was 6 feet wide, 10 feet long and 4.5 feet deep. Furniture to be stripped was placed on a metal grid hung from the top of the enclosed spray system. The rack was lowered into the tank and the lip dropped to formmore » the cover of the enclosed system. A hole in the lid was connected to a water bed mattress which lays on top of the lip. During the stripping process, vapors were emitted through the hole, causing the mattress to expand. At the completion of the stripping process the vapors slowly dissipated into the tank, leaving the mattress in its original form. A single personal sample collected during the stripping and rinsing operations showed a methylene-chloride concentration of 68 parts per million (ppm). If the rinse area were also controlled, the enclosed system could keep the concentration below the 25ppm level. The system was homemade and not commercially available. The authors conclude that the system, while apparently effective, was also expensive. It is not recommended for further study at this time.« less

Film Vetoes for Alpha Background Rejection in Bolometer Detectors

NASA Astrophysics Data System (ADS)

Deporzio, Nicholas; Bucci, Carlo; Canonica, Lucia; Divacri, Marialaura; Cuore Collaboration; Absurd Team

2015-04-01

This study characterizes the effectiveness of encasing bolometer detectors in scintillator, metal ionization, and more exotic films to veto alpha radiation background. Bolometers are highly susceptible to alpha background and a successful veto should boost the statistical strength, speed, and signal-background ratio of bolometer particle searches. Plastic scintillator films are cooled to bolometer temperatures and bombarded with 1.4 MeV to 6.0 MeV alpha particles representative of detector conditions. Photomultipliers detect the keV range scintillation light and produce a veto signal. Also, layered films of a primary metal, dielectric, and secondary metal, such as gold-polyethylene-gold films, are cooled to milli-kelvin temperatures and biased with 0.1V to 100V to produce a current signal when incident 1.4 MeV to 6.0 MeV alpha particles ionize conduction paths through the film. Veto signals are characterized by their affect on bolometer detection of 865 keV target signals. Similar methods are applied to more exotic films. Early results show scintillator films raise target signal count rate and suppress counts above target energy by at least a factor of 10. This indicates scintillation vetoes are effective and that metal ionization and other films under study will also be effective.

Walking Perception by Walking Observers

ERIC Educational Resources Information Center

Jacobs, Alissa; Shiffrar, Maggie

2005-01-01

People frequently analyze the actions of other people for the purpose of action coordination. To understand whether such self-relative action perception differs from other-relative action perception, the authors had observers either compare their own walking speed with that of a point-light walker or compare the walking speeds of 2 point-light…

Walk Score®

PubMed Central

Brown, Scott C.; Pantin, Hilda; Lombard, Joanna; Toro, Matthew; Huang, Shi; Plater-Zyberk, Elizabeth; Perrino, Tatiana; Perez-Gomez, Gianna; Barrera-Allen, Lloyd; Szapocznik, José

2013-01-01

Background Walk Score® is a nationally and publicly available metric of neighborhood walkability based on proximity to amenities (e.g., retail, food, schools). However, few studies have examined the relationship of Walk Score to walking behavior. Purpose To examine the relationship of Walk Score to walking behavior in a sample of recent Cuban immigrants, who overwhelmingly report little choice in their selection of neighborhood built environments when they arrive in the U.S. Methods Participants were 391 recent healthy Cuban immigrants (M age=37.1 years) recruited within 90 days of arrival in the U.S., and assessed within 4 months of arrival (M=41.0 days in the U.S.), who resided throughout Miami-Dade County FL. Data on participants’ addresses, walking and sociodemographics were collected prospectively from 2008 to 2010. Analyses conducted in 2011 examined the relationship of Walk Score for each participant’s residential address in the U.S. to purposive walking, controlling for age, gender, education, BMI, days in the U.S., and habitual physical activity level in Cuba. Results For each 10-point increase in Walk Score, adjusting for covariates, there was a significant 19% increase in the likelihood of purposive walking, a 26% increase in the likelihood of meeting physical activity recommendations by walking, and 27% more minutes walked in the previous week. Conclusions Results suggest that Walk Score is associated with walking in a sample of recent immigrants who initially had little choice in where they lived in the U.S. These results support existing guidelines indicating that mixed land use (such as parks and restaurants near homes) should be included when designing walkable communities. PMID:23867028

Timing resolution and time walk in SLiK SPAD: measurement and optimization

NASA Astrophysics Data System (ADS)

Fong, Bernicy S.; Davies, Murray; Deschamps, Pierre

2017-08-01

Timing resolution (or timing jitter) and time walk are separate parameters associated with a detector's response time. Studies have been done mostly on the time resolution of various single photon detectors [1]. As the designer and manufacturer of the ultra-low noise (ƙ-factor) silicon avalanche photodiode the SLiK SPAD, which is used in many single photon counting applications, we often get inquiries from customers to better understand how this detector behaves under different operating conditions. Hence, here we will be focusing on the study of these time related parameters specifically for the SLiK SPAD, as a way to provide the most direct information for users of this detector to help with its use more efficiently and effectively. We will be providing the study data on how these parameters can be affected by temperature (both intrinsic to the detector chip and environmental input based on operating conditions), operating voltage, photon wavelength, as well as light spot size. How these parameters can be optimized and the trade-offs from optimization from the desired performance will be presented.

Shared and task-specific muscle synergies of Nordic walking and conventional walking.

PubMed

Boccia, G; Zoppirolli, C; Bortolan, L; Schena, F; Pellegrini, B

2018-03-01

Nordic walking is a form of walking that includes a poling action, and therefore an additional subtask, with respect to conventional walking. The aim of this study was to assess whether Nordic walking required a task-specific muscle coordination with respect to conventional walking. We compared the electromyographic (EMG) activity of 15 upper- and lower-limb muscles of 9 Nordic walking instructors, while executing Nordic walking and conventional walking at 1.3 ms -1 on a treadmill. Non-negative matrix factorization method was applied to identify muscle synergies, representing the spatial and temporal organization of muscle coordination. The number of muscle synergies was not different between Nordic walking (5.2 ± 0.4) and conventional walking (5.0 ± 0.7, P = .423). Five muscle synergies accounted for 91.2 ± 1.1% and 92.9 ± 1.2% of total EMG variance in Nordic walking and conventional walking, respectively. Similarity and cross-reconstruction analyses showed that 4 muscle synergies, mainly involving lower-limb and trunk muscles, are shared between Nordic walking and conventional walking. One synergy acting during upper limb propulsion is specific to Nordic walking, modifying the spatial organization and the magnitude of activation of upper limb muscles compared to conventional walking. The inclusion of the poling action in Nordic walking does not increase the complexity of movement control and does not change the coordination of lower limb muscles. This makes Nordic walking a physical activity suitable also for people with low motor skill. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Quantum Ultra-Walks: Walks on a Line with Spatial Disorder

NASA Astrophysics Data System (ADS)

Boettcher, Stefan; Falkner, Stefan

We discuss the model of a heterogeneous discrete-time walk on a line with spatial disorder in the form of a set of ultrametric barriers. Simulations show that such an quantum ultra-walk spreads with a walk exponent dw that ranges from ballistic (dw = 1) to complete confinement (dw = ∞) for increasing separation 1 <= 1 / ɛ < ∞ in barrier heights. We develop a formalism by which the classical random walk as well as the quantum walk can be treated in parallel using a coined walk with internal degrees of freedom. For the random walk, this amounts to a 2nd -order Markov process with a stochastic coin, better know as an (anti-)persistent walk. The exact analysis, based on the real-space renormalization group (RG), reproduces the results of the well-known model of ``ultradiffusion,'' dw = 1 -log2 ɛ for 0 < ɛ <= 1 / 2 . However, while the evaluation of the RG fixed-points proceeds virtually identical, for the corresponding quantum walk with a unitary coin it fails to reproduce the numerical results. A new way to analyze the RG is indicated. Supported by NSF-DMR 1207431.

Industrial-hygiene walk-through survey report of Copolymer Rubber and Chemical Corporation, Baton Rouge, Louisiana. Industrywide study

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

Roberts, D.R.; Krishnan, E.R.

1986-06-01

A walk through survey was conducted at the Copolymer Rubber and Chemical Corporation, Baton Rouge, Louisiana. The facility produces 465 million pounds of styrene butadiene rubber (SBR) and 15 million pounds of nitrile butadiene rubber (NBR) annually, requiring 120 million pounds of 1,3-butadiene. Of 470 employees, 143 were directly involved in reaction, recovery, and finishing operations, and were potentially exposed to 1,3-butadiene 8 hours per day.

Demonstration of high-responsivity epitaxial β-Ga2O3/GaN metal–heterojunction-metal broadband UV-A/UV-C detector

NASA Astrophysics Data System (ADS)

Kalra, Anisha; Vura, Sandeep; Rathkanthiwar, Shashwat; Muralidharan, Rangarajan; Raghavan, Srinivasan; Nath, Digbijoy N.

2018-06-01

We demonstrate epitaxial β-Ga2O3/GaN-based vertical metal–heterojunction-metal (MHM) broadband UV-A/UV-C photodetectors with high responsivity (3.7 A/W) at 256 and 365 nm, UV-to-visible rejection >103, and a photo-to-dark current ratio of ∼100. A small (large) conduction (valence) band offset at the heterojunction of pulsed laser deposition (PLD)-grown β-Ga2O3 on metal organic chemical vapor deposition (MOCVD)-grown GaN-on-silicon with epitaxial registry, as confirmed by X-ray diffraction (XRD) azimuthal scanning, is exploited to realize detectors with an asymmetric photoresponse and is explained with one-dimensional (1D) band diagram simulations. The demonstrated novel vertical MHM detectors on silicon are fully scalable and promising for enabling focal plane arrays for broadband ultraviolet sensing.

Wafer-fused semiconductor radiation detector

DOEpatents

Lee, Edwin Y.; James, Ralph B.

2002-01-01

Wafer-fused semiconductor radiation detector useful for gamma-ray and x-ray spectrometers and imaging systems. The detector is fabricated using wafer fusion to insert an electrically conductive grid, typically comprising a metal, between two solid semiconductor pieces, one having a cathode (negative electrode) and the other having an anode (positive electrode). The wafer fused semiconductor radiation detector functions like the commonly used Frisch grid radiation detector, in which an electrically conductive grid is inserted in high vacuum between the cathode and the anode. The wafer-fused semiconductor radiation detector can be fabricated using the same or two different semiconductor materials of different sizes and of the same or different thicknesses; and it may utilize a wide range of metals, or other electrically conducting materials, to form the grid, to optimize the detector performance, without being constrained by structural dissimilarity of the individual parts. The wafer-fused detector is basically formed, for example, by etching spaced grooves across one end of one of two pieces of semiconductor materials, partially filling the grooves with a selected electrical conductor which forms a grid electrode, and then fusing the grooved end of the one semiconductor piece to an end of the other semiconductor piece with a cathode and an anode being formed on opposite ends of the semiconductor pieces.

Catoptric electrodes: transparent metal electrodes using shaped surfaces.

PubMed

Kik, Pieter G

2014-09-01

An optical electrode design is presented that theoretically allows 100% optical transmission through an interdigitated metallic electrode at 50% metal areal coverage. This is achieved by redirection of light incident on embedded metal electrode lines to an angle beyond that required for total internal reflection. Full-field electromagnetic simulations using realistic material parameters demonstrate 84% frequency-averaged transmission for unpolarized illumination across the entire visible spectral range using a silver interdigitated electrode at 50% areal coverage. The redirection is achieved through specular reflection, making it nonresonant and arbitrarily broadband, provided the electrode width exceeds the optical wavelength. These findings could significantly improve the performance of photovoltaic devices and optical detectors that require high-conductivity top contacts.

Walk-through survey report: control technology for fermentation processes at Wyeth Laboratories, Inc. , West Chester, Pennsylvania

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

Martinez, K.F.

A walk-through survey was conducted at Wyeth Laboratories, Incorporated, West Chester, Pennsylvania in November, 1983. The purpose of the survey was to evaluate the control technology for the fermentation processes. The facility produced penicillin-V and penicillin-G using the microbial strain Penicillium-chrysogenum. Medical examinations were available for fermentation and extraction process workers. Safety shoes and glasses and disposable dust respirators were provided. The author concludes that Wyeth has in operation an apparently effective system of control measures.

Kinematic evaluation of virtual walking trajectories.

PubMed

Cirio, Gabriel; Olivier, Anne-Hélène; Marchal, Maud; Pettré, Julien

2013-04-01

Virtual walking, a fundamental task in Virtual Reality (VR), is greatly influenced by the locomotion interface being used, by the specificities of input and output devices, and by the way the virtual environment is represented. No matter how virtual walking is controlled, the generation of realistic virtual trajectories is absolutely required for some applications, especially those dedicated to the study of walking behaviors in VR, navigation through virtual places for architecture, rehabilitation and training. Previous studies focused on evaluating the realism of locomotion trajectories have mostly considered the result of the locomotion task (efficiency, accuracy) and its subjective perception (presence, cybersickness). Few focused on the locomotion trajectory itself, but in situation of geometrically constrained task. In this paper, we study the realism of unconstrained trajectories produced during virtual walking by addressing the following question: did the user reach his destination by virtually walking along a trajectory he would have followed in similar real conditions? To this end, we propose a comprehensive evaluation framework consisting on a set of trajectographical criteria and a locomotion model to generate reference trajectories. We consider a simple locomotion task where users walk between two oriented points in space. The travel path is analyzed both geometrically and temporally in comparison to simulated reference trajectories. In addition, we demonstrate the framework over a user study which considered an initial set of common and frequent virtual walking conditions, namely different input devices, output display devices, control laws, and visualization modalities. The study provides insight into the relative contributions of each condition to the overall realism of the resulting virtual trajectories.

Development of dual sensor hand-held detector

NASA Astrophysics Data System (ADS)

Sezgin, Mehmet

2010-04-01

In this paper hand-held dual sensor detector development requirements are considered dedicated to buried object detection. Design characteristics of such a system are categorized and listed. Hardware and software structures, ergonomics, user interface, environmental and EMC/EMI tests to be applied and performance test issues are studied. Main properties of the developed system (SEZER) are presented, which contains Metal Detector (MD) and Ground Penetrating Radar (GPR). The realized system has ergonomic structure and can detect both metallic and non-metallic buried objects. Moreover classification of target is possible if it was defined to the signal processing software in learning phase.

Evaluation of a prototype correction algorithm to reduce metal artefacts in flat detector computed tomography of scaphoid fixation screws.

PubMed

Filli, Lukas; Marcon, Magda; Scholz, Bernhard; Calcagni, Maurizio; Finkenstädt, Tim; Andreisek, Gustav; Guggenberger, Roman

2014-12-01

The aim of this study was to evaluate a prototype correction algorithm to reduce metal artefacts in flat detector computed tomography (FDCT) of scaphoid fixation screws. FDCT has gained interest in imaging small anatomic structures of the appendicular skeleton. Angiographic C-arm systems with flat detectors allow fluoroscopy and FDCT imaging in a one-stop procedure emphasizing their role as an ideal intraoperative imaging tool. However, FDCT imaging can be significantly impaired by artefacts induced by fixation screws. Following ethical board approval, commercially available scaphoid fixation screws were inserted into six cadaveric specimens in order to fix artificially induced scaphoid fractures. FDCT images corrected with the algorithm were compared to uncorrected images both quantitatively and qualitatively by two independent radiologists in terms of artefacts, screw contour, fracture line visibility, bone visibility, and soft tissue definition. Normal distribution of variables was evaluated using the Kolmogorov-Smirnov test. In case of normal distribution, quantitative variables were compared using paired Student's t tests. The Wilcoxon signed-rank test was used for quantitative variables without normal distribution and all qualitative variables. A p value of < 0.05 was considered to indicate statistically significant differences. Metal artefacts were significantly reduced by the correction algorithm (p < 0.001), and the fracture line was more clearly defined (p < 0.01). The inter-observer reliability was "almost perfect" (intra-class correlation coefficient 0.85, p < 0.001). The prototype correction algorithm in FDCT for metal artefacts induced by scaphoid fixation screws may facilitate intra- and postoperative follow-up imaging. Flat detector computed tomography (FDCT) is a helpful imaging tool for scaphoid fixation. The correction algorithm significantly reduces artefacts in FDCT induced by scaphoid fixation screws. This may facilitate intra

Muon energy estimate through multiple scattering with the MACRO detector

NASA Astrophysics Data System (ADS)

Ambrosio, M.; Antolini, R.; Auriemma, G.; Bakari, D.; Baldini, A.; Barbarino, G. C.; Barish, B. C.; Battistoni, G.; Becherini, Y.; Bellotti, R.; Bemporad, C.; Bernardini, P.; Bilokon, H.; Bloise, C.; Bower, C.; Brigida, M.; Bussino, S.; Cafagna, F.; Calicchio, M.; Campana, D.; Candela, A.; Carboni, M.; Caruso, R.; Cassese, F.; Cecchini, S.; Cei, F.; Chiarella, V.; Choudhary, B. C.; Coutu, S.; Cozzi, M.; de Cataldo, G.; de Deo, M.; Dekhissi, H.; de Marzo, C.; de Mitri, I.; Derkaoui, J.; de Vincenzi, M.; di Credico, A.; Dincecco, M.; Erriquez, O.; Favuzzi, C.; Forti, C.; Fusco, P.; Giacomelli, G.; Giannini, G.; Giglietto, N.; Giorgini, M.; Grassi, M.; Gray, L.; Grillo, A.; Guarino, F.; Gustavino, C.; Habig, A.; Hanson, K.; Heinz, R.; Iarocci, E.; Katsavounidis, E.; Katsavounidis, I.; Kearns, E.; Kim, H.; Kyriazopoulou, S.; Lamanna, E.; Lane, C.; Levin, D. S.; Lindozzi, M.; Lipari, P.; Longley, N. P.; Longo, M. J.; Loparco, F.; Maaroufi, F.; Mancarella, G.; Mandrioli, G.; Margiotta, A.; Marini, A.; Martello, D.; Marzari-Chiesa, A.; Mazziotta, M. N.; Michael, D. G.; Monacelli, P.; Montaruli, T.; Monteno, M.; Mufson, S.; Musser, J.; Nicolo, D.; Nolty, R.; Orth, C.; Osteria, G.; Palamara, O.; Patera, V.; Patrizii, L.; Pazzi, R.; Peck, C. W.; Perrone, L.; Petrera, S.; Pistilli, P.; Popa, V.; Raino, A.; Reynoldson, J.; Ronga, F.; Rrhioua, A.; Satriano, C.; Scapparone, E.; Scholberg, K.; Sciubba, A.; Serra, P.; Sioli, M.; Sirri, G.; Sitta, M.; Spinelli, P.; Spinetti, M.; Spurio, M.; Steinberg, R.; Stone, J. L.; Sulak, L. R.; Surdo, A.; Tarle, G.; Tatananni, E.; Togo, V.; Vakili, M.; Walter, C. W.; Webb, R.; MACRO Collaboration

2002-10-01

Muon energy measurement represents an important issue for any experiment addressing neutrino-induced up-going muon studies. Since the neutrino oscillation probability depends on the neutrino energy, a measurement of the muon energy adds an important piece of information concerning the neutrino system. We show in this paper how the MACRO limited streamer tube system can be operated in drift mode by using the TDCs included in the QTPs, an electronics designed for magnetic monopole search. An improvement of the space resolution is obtained, through an analysis of the multiple scattering of muon tracks as they pass through our detector. This information can be used further to obtain an estimate of the energy of muons crossing the detector. Here we present the results of two dedicated tests, performed at CERN PS-T9 and SPS-X7 beam lines, to provide a full check of the electronics and to exploit the feasibility of such a multiple scattering analysis. We show that by using a neural network approach, we are able to reconstruct the muon energy for E μ<40 GeV. The test beam data provide an absolute energy calibration, which allows us to apply this method to MACRO data.

Research on Walking Wheel Slippage Control of Live Inspection Robot

NASA Astrophysics Data System (ADS)

Yan, Yu; Liu, Xiaqing; Guo, Hao; Li, Jinliang; Liu, Lanlan

2017-07-01

To solve the problem of walking wheel slippage of a live inspection robot during walking or climbing, this paper analyzes the climbing capacity of the robot with a statics method, designs a pressing wheel mechanism, and presents a method of indirectly identifying walking wheel slippage by reading speed of the pressing wheel due to the fact that the linear speed of the pressing wheel and the walking wheel at the contract point is the same; and finds that the slippage state can not be controlled through accurate mathematical models after identifying the slippage state, whereas slippage can be controlled with fuzzy control. The experiment results indicate that due to design of the pressing wheel mechanism, friction force of the walking wheel is increased, and the climbing capability of the robot is improved. Within the range of climbing capability of the robot, gradient is the key factor that has influence on slippage of robot, and slippage can be effectively eliminated through the fuzzy control method proposed in this paper.

Detectors

DOEpatents

Orr, Christopher Henry; Luff, Craig Janson; Dockray, Thomas; Macarthur, Duncan Whittemore; Bounds, John Alan; Allander, Krag

2002-01-01

The apparatus and method provide techniques through which both alpha and beta emission determinations can be made simultaneously using a simple detector structure. The technique uses a beta detector covered in an electrically conducting material, the electrically conducting material discharging ions generated by alpha emissions, and as a consequence providing a measure of those alpha emissions. The technique also offers improved mountings for alpha detectors and other forms of detectors against vibration and the consequential effects vibration has on measurement accuracy.

Deterministic Walks with Choice

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

Beeler, Katy E.; Berenhaut, Kenneth S.; Cooper, Joshua N.

2014-01-10

This paper studies deterministic movement over toroidal grids, integrating local information, bounded memory and choice at individual nodes. The research is motivated by recent work on deterministic random walks, and applications in multi-agent systems. Several results regarding passing tokens through toroidal grids are discussed, as well as some open questions.

Compensatory balance reactions during forward and backward walking on a treadmill.

PubMed

Bolton, D A E; Misiaszek, J E

2012-04-01

Previous work suggests that balance perturbations to the body opposing the direction of progression during walking lead to larger amplitude corrective reactions than perturbations concurrent with walking direction. To test this hypothesis, subjects received forward and backward perturbations applied to the pelvis through a padded harness, while walking forwards or backwards on a treadmill. Contrary to our hypothesis, the greatest responses were associated with backward perturbations regardless of the direction of walking. Copyright © 2011 Elsevier B.V. All rights reserved.

The effect of light touch on balance control during overground walking in healthy young adults.

PubMed

Oates, A R; Unger, J; Arnold, C M; Fung, J; Lanovaz, J L

2017-12-01

Balance control is essential for safe walking. Adding haptic input through light touch may improve walking balance; however, evidence is limited. This research investigated the effect of added haptic input through light touch in healthy young adults during challenging walking conditions. Sixteen individuals walked normally, in tandem, and on a compliant, low-lying balance beam with and without light touch on a railing. Three-dimensional kinematic data were captured to compute stride velocity (m/s), relative time spent in double support (%DS), a medial-lateral margin of stability (MOS ML ) and its variance (MOS ML CV), as well as a symmetry index (SI) for the MOS ML . Muscle activity was evaluated by integrating electromyography signals for the soleus, tibialis anterior, and gluteus medius muscles bilaterally. Adding haptic input decreased stride velocity, increased the %DS, had no effect on the MOS ML magnitude, decreased the MOS ML CV, had no effect on the SI, and increased activity of most muscles examined during normal walking. During tandem walking, stride velocity and the MOS ML CV decreased, while %DS, MOS ML magnitude, SI, and muscle activity did not change with light touch. When walking on a low-lying, compliant balance beam, light touch had no effect on walking velocity, MOS ML magnitude, or muscle activity; however, the %DS increased and the MOS ML CV and SI decreased when lightly touching a railing while walking on the balance beam. The decreases in the MOS ML CV with light touch across all walking conditions suggest that adding haptic input through light touch on a railing may improve balance control during walking through reduced variability.

Paired emitter-detector diode detection with dual wavelength monitoring for enhanced sensitivity to transition metals in ion chromatography with post-column reaction.

PubMed

O' Toole, Martina; Barron, Leon; Shepherd, Roderick; Paull, Brett; Nesterenko, Pavel; Diamond, Dermot

2009-01-01

The combination of post-column derivatisation and visible detection are regularly employed in ion chromatography (IC) to detect poorly absorbing species. Although this mode is often highly sensitive, one disadvantage is the increase in repeating baseline artifacts associated with out-of-sync pumping systems. The work presented here will demonstrate the use of a second generation design paired emitter-detector diode (PEDD-II) detection mode offering enhanced sensitivity to transition metals in IC by markedly reducing this problem and also by improving signal noise. First generation designs demonstrated the use of a single integrated PEDD detector cell as a simple, small (15 x 5 mm), highly sensitive, low cost photometric detector for the detection of metals in IC. The basic principle of this detection mode lies in the employment of two linear light emitting diodes (LEDs), one operating in normal mode as a light source and the other in reverse bias serving as a light detector. The second generation PEDD-II design showed increased sensitivity for Mn(II)- and Co(II)-2-(pyridylazo)resorcinol (PAR) complexes as a result of two simultaneously acquiring detection cells--one analytical PEDD cell and one reference PEDD cell. Therefore, the PEDD-II employs two wavelengths whereby one monitors the analyte reaction product and the second monitors a wavelength close to the isosbestic point. The optimum LED wavelength to be used for the analytical cell was investigated to maximise peak response. The fabrication process for both the analytical and reference PEDD cells was validated by determining the reproducibility of detectors within a batch. The reproducibility and sensitivity of the PEDD-II detector was then investigated using signals obtained from both intra- and inter-day chromatograms.

Manipulation and measurement of pH sensitive metal-ligand binding using electrochemical proton generation and metal detection.

PubMed

Read, Tania L; Joseph, Maxim B; Macpherson, Julie V

2016-01-31

Generator-detector electrodes can be used to both perturb and monitor pH dependant metal-ligand binding equilibria, in situ. In particular, protons generated at the generator locally influence the speciation of metal (Cu(2+)) in the presence of ligand (triethylenetetraamine), with the detector employed to monitor, in real time, free metal (Cu(2+)) concentrations.

Through-Metal-Wall Power Delivery and Data Transmission for Enclosed Sensors: A Review

PubMed Central

Yang, Ding-Xin; Hu, Zheng; Zhao, Hong; Hu, Hai-Feng; Sun, Yun-Zhe; Hou, Bao-Jian

2015-01-01

The aim of this review was to assess the current viable technologies for wireless power delivery and data transmission through metal barriers. Using such technologies sensors enclosed in hermetical metal containers can be powered and communicate through exterior power sources without penetration of the metal wall for wire feed-throughs. In this review, we first discuss the significant and essential requirements for through-metal-wall power delivery and data transmission and then we: (1) describe three electromagnetic coupling based techniques reported in the literature, which include inductive coupling, capacitive coupling, and magnetic resonance coupling; (2) present a detailed review of wireless ultrasonic through-metal-wall power delivery and/or data transmission methods; (3) compare various ultrasonic through-metal-wall systems in modeling, transducer configuration and communication mode with sensors; (4) summarize the characteristics of electromagnetic-based and ultrasound-based systems, evaluate the challenges and development trends. We conclude that electromagnetic coupling methods are suitable for through thin non-ferromagnetic metal wall power delivery and data transmission at a relatively low data rate; piezoelectric transducer-based ultrasonic systems are particularly advantageous in achieving high power transfer efficiency and high data rates; the combination of more than one single technique may provide a more practical and reliable solution for long term operation. PMID:26694392

Transformation through Repetition: Walking, Listening and Drawing on Tlicho Lands

ERIC Educational Resources Information Center

Ruiz, Adolfo

2017-01-01

As part of my PhD practice-based research on Tlicho lands (a self-governed Indigenous region in Canada's Northwest Territories), drawing is being used to embody intangible cultural heritage (which includes activities such as oral history and the social practice of walking). Recent work to emerge from this research consists of two drawings created…

A Walk on Ice.

ERIC Educational Resources Information Center

Turner, Jane

1998-01-01

Exploration of a specific use of Text Based Virtual Reality--not just as powerful communities for authentic communication and collaboration in language learning but exploiting role-playing and writing aspects. The "Walk on Ice" takes a group of adult English-as-a-Second-Language learners through the creation of imaginary characters who…

Multi-spectral black meta-infrared detectors (Conference Presentation)

NASA Astrophysics Data System (ADS)

Krishna, Sanjay

2016-09-01

There is an increased emphasis on obtaining imaging systems with on-demand spectro-polarimetric information at the pixel level. Meta-infrared detectors in which infrared detectors are combined with metamaterials are a promising way to realize this. The infrared region is appealing due to the low metallic loss, large penetration depth of the localized field and the larger feature sizes compared to the visible region. I will discuss approaches to realize multispectral detectors including our recent work on double metal meta-material design combined with Type II superlattices that have demonstrated enhanced quantum efficiency (collaboration with Padilla group at Duke University).

KidsWalk-to-School: A Guide To Promote Walking to School.

ERIC Educational Resources Information Center

Center for Chronic Disease Prevention and Health Promotion (DHHS/CDC), Atlanta, GA.

This guide encourages people to create safe walking and biking routes to school, promoting four issues: physically active travel, safe and walkable routes to school, crime prevention, and health environments. The chapters include: "KidsWalk-to-School: A Guide to Promote Walking to School" (Is there a solution? Why is walking to school important?…

The Walking Wellness Teacher's Guide. A Resource Book for Elementary & Middle School Teachers.

ERIC Educational Resources Information Center

Sweetgall, Robert; Neeves, Robert

This teacher's resource guide for implementing a "Walking Wellness" curriculum in grades four through eight offers 16 hands-on workshops. Activities focus on fitness walking, cardiovascular conditioning, nutrition and weight control, walking techniques and posture, stress control, tobacco-free living, and lifestyle planning. The student…

A Polarization-Dependent Normal Incident Quantum Cascade Detector Enhanced Via Metamaterial Resonators.

PubMed

Wang, Lei; Zhai, Shen-Qiang; Wang, Feng-Jiao; Liu, Jun-Qi; Liu, Shu-Man; Zhuo, Ning; Zhang, Chuan-Jin; Wang, Li-Jun; Liu, Feng-Qi; Wang, Zhan-Guo

2016-12-01

The design, fabrication, and characterization of a polarization-dependent normal incident quantum cascade detector coupled via complementary split-ring metamaterial resonators in the infrared regime are presented. The metamaterial structure is designed through three-dimensional finite-difference time-domain method and fabricated on the top metal contact, which forms a double-metal waveguide together with the metallic ground plane. With normal incidence, significant enhancements of photocurrent response are obtained at the metamaterial resonances compared with the 45° polished edge coupling device. The photocurrent response enhancements exhibit clearly polarization dependence, and the largest response enhancement factor of 165% is gained for the incident light polarized parallel to the split-ring gap.

A Simple 2-Transistor Touch or Lick Detector Circuit

ERIC Educational Resources Information Center

Slotnick, Burton

2009-01-01

Contact or touch detectors in which a subject acts as a switch between two metal surfaces have proven more popular and arguably more useful for recording responses than capacitance switches, photocell detectors, and force detectors. Components for touch detectors circuits are inexpensive and, except for some special purpose designs, can be easily…

Walking Beliefs in Women With Fibromyalgia: Clinical Profile and Impact on Walking Behavior.

PubMed

Peñacoba, Cecilia; Pastor, María-Ángeles; López-Roig, Sofía; Velasco, Lilian; Lledo, Ana

2017-10-01

Although exercise is essential for the treatment of fibromyalgia, adherence is low. Walking, as a form of physical exercise, has significant advantages. The aim of this article is to describe, in 920 women with fibromyalgia, the prevalence of certain walking beliefs and analyze their effects both on the walking behavior itself and on the associated symptoms when patients walk according to a clinically recommended way. The results highlight the high prevalence of beliefs related to pain and fatigue as walking-inhibitors. In the whole sample, beliefs are associated with an increased perception that comorbidity prevents walking, and with higher levels of pain and fatigue. In patients who walk regularly, beliefs are only associated with the perception that comorbidity prevents them from walking. It is necessary to promote walking according to the established way (including breaks to prevent fatigue) and to implement interventions on the most prevalent beliefs that inhibit walking.

Using a metal detector to determine lead sinker abundance in waterbird habitat

USGS Publications Warehouse

Duerr, A.E.; DeStefano, S.

2000-01-01

Waterbirds have died of lead poisoning from ingesting lead fishing sinkers in the United States and Europe. Estimating abundance and distribution of sinkers in the environment will help researchers to understand the potential effects of lead poisoning from sinker ingestion. We used a metal detector to test how environmental conditions and sinker characteristics affected detection of sinkers. Odds of detecting a lead sinker depended on the interaction of sinker mass and depth where it was buried (P=0.002). The odds of detecting a sinker increased with mass and decreased with depth buried. Lead split-shot sinkers were less detectable than tin, brass, and stainless steel sinkers. Detecting lead sinkers was not influenced by sinker shape, substrate type, or whether we searched underwater or on land. We developed a model to determine the proportion of sinkers detected when this detector is used to search for sinkers, so sinker abundance can be estimated. The log odds (Logit) of detecting a lead sinker with mass M g buried D cm below the surface was Logit Y= -1.63 + 4.20 M - 0.45 D - 0.27 MD + 0.0002 D2. The probability of detecting a lead sinker was e(Logit Y)/(1 + e(Logit Y)). At the surface, 90% of sinkers with mass 0.9 g will be detected.

Development, implementation and evaluation of a dedicated metal artefact reduction method for interventional flat-detector CT.

PubMed

Prell, D; Kalender, W A; Kyriakou, Y

2010-12-01

The purpose of this study was to develop, implement and evaluate a dedicated metal artefact reduction (MAR) method for flat-detector CT (FDCT). The algorithm uses the multidimensional raw data space to calculate surrogate attenuation values for the original metal traces in the raw data domain. The metal traces are detected automatically by a three-dimensional, threshold-based segmentation algorithm in an initial reconstructed image volume, based on twofold histogram information for calculating appropriate metal thresholds. These thresholds are combined with constrained morphological operations in the projection domain. A subsequent reconstruction of the modified raw data yields an artefact-reduced image volume that is further processed by a combining procedure that reinserts the missing metal information. For image quality assessment, measurements on semi-anthropomorphic phantoms containing metallic inserts were evaluated in terms of CT value accuracy, image noise and spatial resolution before and after correction. Measurements of the same phantoms without prostheses were used as ground truth for comparison. Cadaver measurements were performed on complex and realistic cases and to determine the influences of our correction method on the tissue surrounding the prostheses. The results showed a significant reduction of metal-induced streak artefacts (CT value differences were reduced to below 22 HU and image noise reduction of up to 200%). The cadaver measurements showed excellent results for imaging areas close to the implant and exceptional artefact suppression in these areas. Furthermore, measurements in the knee and spine regions confirmed the superiority of our method to standard one-dimensional, linear interpolation.

Quantum Walk Schemes for Universal Quantum Computation

NASA Astrophysics Data System (ADS)

Underwood, Michael S.

Random walks are a powerful tool for the efficient implementation of algorithms in classical computation. Their quantum-mechanical analogues, called quantum walks, hold similar promise. Quantum walks provide a model of quantum computation that has recently been shown to be equivalent in power to the standard circuit model. As in the classical case, quantum walks take place on graphs and can undergo discrete or continuous evolution, though quantum evolution is unitary and therefore deterministic until a measurement is made. This thesis considers the usefulness of continuous-time quantum walks to quantum computation from the perspectives of both their fundamental power under various formulations, and their applicability in practical experiments. In one extant scheme, logical gates are effected by scattering processes. The results of an exhaustive search for single-qubit operations in this model are presented. It is shown that the number of distinct operations increases exponentially with the number of vertices in the scattering graph. A catalogue of all graphs on up to nine vertices that implement single-qubit unitaries at a specific set of momenta is included in an appendix. I develop a novel scheme for universal quantum computation called the discontinuous quantum walk, in which a continuous-time quantum walker takes discrete steps of evolution via perfect quantum state transfer through small 'widget' graphs. The discontinuous quantum-walk scheme requires an exponentially sized graph, as do prior discrete and continuous schemes. To eliminate the inefficient vertex resource requirement, a computation scheme based on multiple discontinuous walkers is presented. In this model, n interacting walkers inhabiting a graph with 2n vertices can implement an arbitrary quantum computation on an input of length n, an exponential savings over previous universal quantum walk schemes. This is the first quantum walk scheme that allows for the application of quantum error correction

Application of metallic magnetic calorimeter in rare event search

NASA Astrophysics Data System (ADS)

Kim, I.; Jo, H. S.; Kang, C. S.; Kim, G. B.; Kim, H. L.; Kim, S. R.; Kim, Y. H.; Lee, H. J.; Lee, J. H.; Lee, M. K.; Oh, S. Y.; So, J. H.

2017-09-01

Metallic magnetic calorimeters (MMCs) are highly sensitive temperature sensors that use the paramagnetic nature of erbium in a metallic host and superconducting electronics usually composed of a superconducting niobium coil and a current sensing superconducting quantum interference device. This article discusses the applicability of MMCs in experimental searches for rare events in particle physics. A detector module using two MMCs was built to perform low-temperature measurements of heat and scintillation light generated by particle interaction in a 340 g 40Ca100MoO4 crystal. The energy transfer mechanism, from incident particles to the components of the heat and light sensors, is described through a thermal model. MMCs, with gold films collecting athermal phonons, can be used over wide ranges of operating temperature and crystal volume without a significant change in detector performances. Rare event searches could thus benefit from MMC-based detectors presenting such flexibility as well as excellent energy resolution and particle discrimination power.

Effects of Nordic walking and walking on spatiotemporal gait parameters and ground reaction force.

PubMed

Park, Seung Kyu; Yang, Dae Jung; Kang, Yang Hun; Kim, Je Ho; Uhm, Yo Han; Lee, Yong Seon

2015-09-01

[Purpose] The purpose of this study was to investigate the effects of Nordic walking and walking on spatiotemporal gait parameters and ground reaction force. [Subjects] The subjects of this study were 30 young adult males, who were divided into a Nordic walking group of 15 subjects and a walking group of 15 subjects. [Methods] To analyze the spatiotemporal parameters and ground reaction force during walking in the two groups, the six-camera Vicon MX motion analysis system was used. The subjects were asked to walk 12 meters using the more comfortable walking method for them between Nordic walking and walking. After they walked 12 meters more than 10 times, their most natural walking patterns were chosen three times and analyzed. To determine the pole for Nordic walking, each subject's height was multiplied by 0.68. We then measured the spatiotemporal gait parameters and ground reaction force. [Results] Compared with the walking group, the Nordic walking group showed an increase in cadence, stride length, and step length, and a decrease in stride time, step time, and vertical ground reaction force. [Conclusion] The results of this study indicate that Nordic walking increases the stride and can be considered as helping patients with diseases affecting their gait. This demonstrates that Nordic walking is more effective in improving functional capabilities by promoting effective energy use and reducing the lower limb load, because the weight of the upper and lower limbs is dispersed during Nordic walking.

Walking drawings and walking ability in children with cerebral palsy.

PubMed

Chong, Jimmy; Mackey, Anna H; Stott, N Susan; Broadbent, Elizabeth

2013-06-01

To investigate whether drawings of the self walking by children with cerebral palsy (CP) were associated with walking ability and illness perceptions. This was an exploratory study in 52 children with CP (M:F = 28:24), mean age 11.1 years (range 5-18), who were attending tertiary level outpatient clinics. Children were asked to draw a picture of themselves walking. Drawing size and content was used to investigate associations with clinical walk tests and children's own perceptions of their CP assessed using a CP version of the Brief Illness Perception Questionnaire. Larger drawings of the self were associated with less distance traveled, higher emotional responses to CP, and lower perceptions of pain or discomfort, independent of age. A larger self-to-overall drawing height ratio was related to walking less distance. Drawings of the self confined within buildings and the absence of other figures were also associated with reduced walking ability. Drawing size and content can reflect walking ability, as well as symptom perceptions and distress. Drawings may be useful for clinicians to use with children with cerebral palsy to aid discussion about their condition. PsycINFO Database Record (c) 2013 APA, all rights reserved.

Bridging the gulf between correlated random walks and Lévy walks: autocorrelation as a source of Lévy walk movement patterns.

PubMed

Reynolds, Andy M

2010-12-06

For many years, the dominant conceptual framework for describing non-oriented animal movement patterns has been the correlated random walk (CRW) model in which an individual's trajectory through space is represented by a sequence of distinct, independent randomly oriented 'moves'. It has long been recognized that the transformation of an animal's continuous movement path into a broken line is necessarily arbitrary and that probability distributions of move lengths and turning angles are model artefacts. Continuous-time analogues of CRWs that overcome this inherent shortcoming have appeared in the literature and are gaining prominence. In these models, velocities evolve as a Markovian process and have exponential autocorrelation. Integration of the velocity process gives the position process. Here, through a simple scaling argument and through an exact analytical analysis, it is shown that autocorrelation inevitably leads to Lévy walk (LW) movement patterns on timescales less than the autocorrelation timescale. This is significant because over recent years there has been an accumulation of evidence from a variety of experimental and theoretical studies that many organisms have movement patterns that can be approximated by LWs, and there is now intense debate about the relative merits of CRWs and LWs as representations of non-orientated animal movement patterns.

A view of metals through the terahertz window

NASA Astrophysics Data System (ADS)

Dodge, Steve

2006-05-01

As electrons move through a metal, interaction with their environment tends to slow them down, causing the Drude peak in the optical conductivity to become narrower. The resulting peak width is typically in the terahertz frequency range that sits between microwaves the far infrared, too fast for conventional electronics and too slow for conventional infrared spectroscopy. With femtosecond laser techniques, however, coherent, broadband terahertz radiation can now be generated and detected with exquisite sensitivity, providing a new window onto electronic interactions in metals. I will discuss the application of this technique to a variety of metallic systems, including elemental lead, the nearly magnetic oxide metal CaRuO3, and CrV alloys that span the quantum phase transition from spin-density wave to paramagnetic metal. M. A. Gilmore, S. Kamal, D. M. Broun, and J. S. Dodge, Appl. Phys. Lett. 88, 141910 (2006).

Walking Performance: Correlation between Energy Cost of Walking and Walking Participation. New Statistical Approach Concerning Outcome Measurement

PubMed Central

Franceschini, Marco; Rampello, Anais; Agosti, Maurizio; Massucci, Maurizio; Bovolenta, Federica; Sale, Patrizio

2013-01-01

Walking ability, though important for quality of life and participation in social and economic activities, can be adversely affected by neurological disorders, such as Spinal Cord Injury, Stroke, Multiple Sclerosis or Traumatic Brain Injury. The aim of this study is to evaluate if the energy cost of walking (CW), in a mixed group of chronic patients with neurological diseases almost 6 months after discharge from rehabilitation wards, can predict the walking performance and any walking restriction on community activities, as indicated by Walking Handicap Scale categories (WHS). One hundred and seven subjects were included in the study, 31 suffering from Stroke, 26 from Spinal Cord Injury and 50 from Multiple Sclerosis. The multivariable binary logistical regression analysis has produced a statistical model with good characteristics of fit and good predictability. This model generated a cut-off value of.40, which enabled us to classify correctly the cases with a percentage of 85.0%. Our research reveal that, in our subjects, CW is the only predictor of the walking performance of in the community, to be compared with the score of WHS. We have been also identifying a cut-off value of CW cost, which makes a distinction between those who can walk in the community and those who cannot do it. In particular, these values could be used to predict the ability to walk in the community when discharged from the rehabilitation units, and to adjust the rehabilitative treatment to improve the performance. PMID:23468871

Participatory Learning Walks: Reflective Practice for the Conductor-Music Educator

ERIC Educational Resources Information Center

Baker, William J.; King, Heidi

2013-01-01

Learning walks can be defined as ongoing, structured classroom visits by senior teachers and other colleagues intended to gather data about teaching and learning through observation and interaction with students. Used in areas such as classroom teaching, learning walks are designed to support professional learning for educators and encourage…

Alzheimer random walk

NASA Astrophysics Data System (ADS)

Odagaki, Takashi; Kasuya, Keisuke

2017-09-01

Using the Monte Carlo simulation, we investigate a memory-impaired self-avoiding walk on a square lattice in which a random walker marks each of sites visited with a given probability p and makes a random walk avoiding the marked sites. Namely, p = 0 and p = 1 correspond to the simple random walk and the self-avoiding walk, respectively. When p> 0, there is a finite probability that the walker is trapped. We show that the trap time distribution can well be fitted by Stacy's Weibull distribution b(a/b){a+1}/{b}[Γ({a+1}/{b})]-1x^a\\exp(-a/bx^b)} where a and b are fitting parameters depending on p. We also find that the mean trap time diverges at p = 0 as p- α with α = 1.89. In order to produce sufficient number of long walks, we exploit the pivot algorithm and obtain the mean square displacement and its Flory exponent ν(p) as functions of p. We find that the exponent determined for 1000 step walks interpolates both limits ν(0) for the simple random walk and ν(1) for the self-avoiding walk as [ ν(p) - ν(0) ] / [ ν(1) - ν(0) ] = pβ with β = 0.388 when p ≪ 0.1 and β = 0.0822 when p ≫ 0.1. Contribution to the Topical Issue "Continuous Time Random Walk Still Trendy: Fifty-year History, Current State and Outlook", edited by Ryszard Kutner and Jaume Masoliver.

Discrete spacetime, quantum walks, and relativistic wave equations

NASA Astrophysics Data System (ADS)

Mlodinow, Leonard; Brun, Todd A.

2018-04-01

It has been observed that quantum walks on regular lattices can give rise to wave equations for relativistic particles in the continuum limit. In this paper, we define the three-dimensional discrete-time walk as a product of three coined one-dimensional walks. The factor corresponding to each one-dimensional walk involves two projection operators that act on an internal coin space; each projector is associated with either the "forward" or "backward" direction in that physical dimension. We show that the simple requirement that there is no preferred axis or direction along an axis—that is, that the walk be symmetric under parity transformations and steps along different axes of the cubic lattice be uncorrelated—leads, in the case of the simplest solution, to the requirement that the continuum limit of the walk is fully Lorentz-invariant. We show further that, in the case of a massive particle, this symmetry requirement necessitates the use of a four-dimensional internal space (as in the Dirac equation). The "coin flip" operation is generated by the parity transformation on the internal coin space, while the differences of the projection operators associated with each dimension must all anticommute. Finally, we discuss the leading correction to the continuum limit, and the possibility of distinguishing through experiment between the discrete random walk and the continuum-based Dirac equation as a description of fermion dynamics.

At similar angles, slope walking has a greater fall risk than stair walking.

PubMed

Sheehan, Riley C; Gottschall, Jinger S

2012-05-01

According to the CDC, falls are the leading cause of injury for all age groups with over half of the falls occurring during slope and stair walking. Consequently, the purpose of this study was to compare and contrast the different factors related to fall risk as they apply to these walking tasks. More specifically, we hypothesized that compared to level walking, slope and stair walking would have greater speed standard deviation, greater ankle dorsiflexion, and earlier peak activity of the tibialis anterior. Twelve healthy, young male participants completed level, slope, and stair trials on a 25-m walkway. Overall, during slope and stair walking, medial-lateral stability was less, anterior-posterior stability was less, and toe clearance was greater in comparison to level walking. In addition, there were fewer differences between level and stair walking than there were between level and slope walking, suggesting that at similar angles, slope walking has a greater fall risk than stair walking. Copyright © 2011 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Nordic walking versus walking without poles for rehabilitation with cardiovascular disease: Randomized controlled trial.

PubMed

Girold, Sébastien; Rousseau, Jérome; Le Gal, Magalie; Coudeyre, Emmanuel; Le Henaff, Jacqueline

2017-07-01

With Nordic walking, or walking with poles, one can travel a greater distance and at a higher rate than with walking without poles, but whether the activity is beneficial for patients with cardiovascular disease is unknown. This randomized controlled trial was undertaken to determine whether Nordic walking was more effective than walking without poles on walk distance to support rehabilitation training for patients with acute coronary syndrome (ACS) and peripheral arterial occlusive disease (PAOD). Patients were recruited in a private specialized rehabilitation centre for cardiovascular diseases. The entire protocol, including patient recruitment, took place over 2 months, from September to October 2013. We divided patients into 2 groups: Nordic Walking Group (NWG, n=21) and Walking Group without poles (WG, n=21). All patients followed the same program over 4 weeks, except for the walk performed with or without poles. The main outcome was walk distance on the 6-min walk test. Secondary outcomes were maximum heart rate during exercise and walk distance and power output on a treadmill stress test. We included 42 patients (35 men; mean age 57.2±11 years and BMI 26.5±4.5kg/m 2 ). At the end of the training period, both groups showed improved walk distance on the 6-min walk test and treatment stress test as well as power on the treadmill stress test (P<0.05). The NWG showed significantly greater walk distance than the WG (P<0.05). Both ACS and PAOD groups showed improvement, but improvement was significant for only PAOD patients. After a 4-week training period, Nordic walking training appeared more efficient than training without poles for increasing walk distance on the 6-min walk test for patients with ACS and PAOD. Copyright © 2017. Published by Elsevier Masson SAS.

Effect of the walking speed to the lower limb joint angular displacements, joint moments and ground reaction forces during walking in water.

PubMed

Miyoshi, Tasuku; Shirota, Takashi; Yamamoto, Shin-ichiro; Nakazawa, Kimitaka; Akai, Masami

2004-06-17

The purpose of this study was to compare the changes in ground reaction forces (GRF), joint angular displacements (JAD), joint moments (JM) and electromyographic (EMG) activities that occur during walking at various speeds in water and on land. Fifteen healthy adults participated in this study. In the water experiments, the water depth was adjusted so that body weight was reduced by 80%. A video-motion analysis system and waterproof force platform was used to obtain kinematics and kinetics data and to calculate the JMs. Results revealed that (1) the anterior-posterior GRF patterns differed between walking in water and walking on land, whereas the medio-lateral GRF patterns were similar, (2) the JAD patterns of the hip and ankle were similar between water- and land-walking, whereas the range of motion at the knee joint was lower in water than on land, (3) the JMs in all three joints were lower in water than on land throughout the stance phase, and (4) the hip joint extension moment and hip extensor muscle EMG activity were increased as walking speed increase during walking in water. Rehabilitative water-walking exercise could be designed to incorporate large-muscle activities, especially of the lower-limb extensor muscles, through full joint range of motion and minimization of joint moments.

Characterization of silicon detectors through TCT at Delhi University

NASA Astrophysics Data System (ADS)

Jain, G.; Lalwani, K.; Dalal, R.; Bhardwaj, A.; Ranjan, K.

2016-07-01

Transient Current Technique (TCT) is one of the important methods to characterize silicon detectors and is based on the time evolution of the charge carriers generated when a laser light is shone on it. For red laser, charge is injected only to a small distance from the surface of the detector. For such a system, one of the charge carriers is collected faster than the readout time of the electronics and therefore, the effective signal at the electrodes is decided by the charge carriers that traverse throughout the active volume of the detector, giving insight to the electric field profile, drift velocity, effective doping density, etc. of the detector. Delhi University is actively involved in the silicon detector R&D and has recently installed a TCT setup consisting of a red laser system, a Faraday cage, a SMU (Source Measuring Unit), a bias tee, and an amplifier. Measurements on a few silicon pad detectors have been performed using the developed system, and the results have been found in good agreement with the CERN setup.

D.U.C.K. Walking.

ERIC Educational Resources Information Center

Steller, Jenifer J.

This manual presents a schoolwide walking program that includes aerobic fitness information, curriculum integration, and walking tours. "Discover and Understand Carolina Kids by Walking" is D.U.C.K. Walking. An aerobic walking activity, D.U.C.K. Walking has two major goals: (1) to promote regular walking as a way to exercise at any age;…

Things that go beep: experience with an ED guideline for use of a handheld metal detector in the management of ingested non-hazardous metallic foreign bodies.

PubMed

Ramlakhan, S L; Burke, D P; Gilchrist, J

2006-06-01

To review compliance with our emergency department (ED) guideline on the imaging of ingested non-hazardous metallic foreign bodies in children, investigate adverse outcomes, and make suggestions for improving the guideline. Retrospective analysis of patients presenting in a 3 year period to a paediatric ED with a history of possible metallic foreign body (MFB) ingestion, who were managed according to an ED guideline. We identified 430 episodes of possible MFB ingestion, of which 422 were eligible for inclusion in the study. Compliance with the guideline was 77.8% with no significant adverse events. The exclusion of symptoms as a criterion for x ray results in a reduction in the x ray rate of 56% in the symptomatic group with no increase in adverse events. A handheld metal detector (HMD) can be safely and reliably used in lieu of plain radiography to investigate children with a history of MFB ingestion, irrespective of symptoms and without incurring any significant adverse events.

A Novel Walking Detection and Step Counting Algorithm Using Unconstrained Smartphones.

PubMed

Kang, Xiaomin; Huang, Baoqi; Qi, Guodong

2018-01-19

Recently, with the development of artificial intelligence technologies and the popularity of mobile devices, walking detection and step counting have gained much attention since they play an important role in the fields of equipment positioning, saving energy, behavior recognition, etc. In this paper, a novel algorithm is proposed to simultaneously detect walking motion and count steps through unconstrained smartphones in the sense that the smartphone placement is not only arbitrary but also alterable. On account of the periodicity of the walking motion and sensitivity of gyroscopes, the proposed algorithm extracts the frequency domain features from three-dimensional (3D) angular velocities of a smartphone through FFT (fast Fourier transform) and identifies whether its holder is walking or not irrespective of its placement. Furthermore, the corresponding step frequency is recursively updated to evaluate the step count in real time. Extensive experiments are conducted by involving eight subjects and different walking scenarios in a realistic environment. It is shown that the proposed method achieves the precision of 93.76 % and recall of 93.65 % for walking detection, and its overall performance is significantly better than other well-known methods. Moreover, the accuracy of step counting by the proposed method is 95.74 % , and is better than both of the several well-known counterparts and commercial products.

Sidewalks promote walking

DOT National Transportation Integrated Search

2004-12-01

Of Americas 205 million adults, 86% took walks during the summer months of 2002, and 40% of those walkers walked more than 15 days per month. Fourteen percent of adult Americans state they never take walks. The presence of sidewalks has a ...

Scavenging energy from human walking through a shoe-mounted piezoelectric harvester

NASA Astrophysics Data System (ADS)

Fan, Kangqi; Liu, Zhaohui; Liu, Haiyan; Wang, Liansong; Zhu, Yingmin; Yu, Bo

2017-04-01

This study presents a shoe-mounted nonlinear piezoelectric energy harvester (PEH) with intent to capture energy from human walking. The PEH consists of a piezoelectric cantilever beam magnetically coupled to a ferromagnetic ball and a crossbeam. A sleeve is included to guide the travel of the ball. Experimental measurements and theoretical simulations demonstrate that the proposed design can collect energy from diverse excitation sources with different directions produced by the foot, including vibrations, swing motions, and the compressive force. The ball and the crossbeam sense the swing motion and the compressive force, respectively, and then actuate the piezoelectric beam to function. The piezoelectric beam senses the vibration along the tibial axis and generates electricity. The proposed PEH achieves the superposition of these excitations and generates multiple peaks in voltage output within one gait cycle. The output power generated by the fabricated prototype ranges from 0.03 mW to 0.35 mW when the walking velocity varies from 2 km/h to 8 km/h.

Development of a novel scintillation-trigger detector for the MTV experiment using aluminum-metallized film tapes

NASA Astrophysics Data System (ADS)

Tanaka, S.; Ozaki, S.; Sakamoto, Y.; Tanuma, R.; Yoshida, T.; Murata, J.

2014-07-01

A new type of a trigger-scintillation counter array designed for the MTV experiment at TRIUMF-ISAC has been developed, which uses aluminum-metallized film tape for wrapping to achieve the required assembling precision of ±0.5 mm. The MTV experiment uses a cylindrical drift chamber (CDC) as the main electron-tracking detector. The barrel-type trigger counter is placed inside the CDC to generate a trigger signal using 1 mm thick, 300 mm long thin plastic scintillation counters. Detection efficiency and light attenuation compared with conventional wrapping materials are studied.

Trapping photons on the line: controllable dynamics of a quantum walk

NASA Astrophysics Data System (ADS)

Xue, Peng; Qin, Hao; Tang, Bao

2014-04-01

Optical interferometers comprising birefringent-crystal beam displacers, wave plates, and phase shifters serve as stable devices for simulating quantum information processes such as heralded coined quantum walks. Quantum walks are important for quantum algorithms, universal quantum computing circuits, quantum transport in complex systems, and demonstrating intriguing nonlinear dynamical quantum phenomena. We introduce fully controllable polarization-independent phase shifters in optical pathes in order to realize site-dependent phase defects. The effectiveness of our interferometer is demonstrated through realizing single-photon quantum-walk dynamics in one dimension. By applying site-dependent phase defects, the translational symmetry of an ideal standard quantum walk is broken resulting in localization effect in a quantum walk architecture. The walk is realized for different site-dependent phase defects and coin settings, indicating the strength of localization signature depends on the level of phase due to site-dependent phase defects and coin settings and opening the way for the implementation of a quantum-walk-based algorithm.

Walking to Save a County.

ERIC Educational Resources Information Center

Slotnick, Karen

1981-01-01

Describes the 10-year history and accomplishments of the Walk to Save the County which has preserved more than 400 acres of Onondaga County, New York. Outlines organizational structure, promotional strategies, awards, and educational opportunities involved in this annual fund-raising hike by third- through eighth-grade students. (NEC)

Stilt walking: how do we learn those first steps?

PubMed

Akram, Sakineh B; Frank, James S

2009-09-01

This study examined how young healthy adults learn stilt walking. Ten healthy male university students attended two sessions of testing held on two consecutive days. In each session participants performed three blocks of 10 stilt-walking trials. Angular movements of head and trunk and the spatial and temporal gait parameters were recorded. When walking on stilts young adults improved their gait velocity through modifications of step parameters while maintaining trunk movements close to that observed during normal over-ground walking. Participants improved their performance by increasing their step frequency and step length and reducing the double support percentage of the gait cycle. Stilts are often used for drywall installation, painting over-the-head areas and raising workers above the ground without the burden of erecting scaffolding. This research examines the locomotor adaptation as young healthy adults learn the complex motor task of stilt walking; a task that is frequently used in the construction industry.

Intraspinal Microstimulation Produces Over-ground Walking in Anesthetized Cats

PubMed Central

Holinski, B.J.; Mazurek, K.A.; Everaert, D.G.; Toossi, A.; Lucas-Osma, A.M.; Troyk, P.; Etienne-Cummings, R.; Stein, R.B.; Mushahwar, V.K.

2016-01-01

Objective Spinal cord injury causes a drastic loss of motor, sensory and autonomic function. The goal of this project was to investigate the use of intraspinal microstimulation (ISMS) for producing long distances of walking over ground. ISMS is an electrical stimulation method developed for restoring motor function by activating spinal networks below the level of an injury. It produces movements of the legs by stimulating the ventral horn of the lumbar enlargement using fine penetrating electrodes (≤ 50µm diameter). Approach In each of five adult cats (4.2–5.5kg), ISMS was applied through 16 electrodes implanted with tips targeting lamina IX in the ventral horn bilaterally. A desktop system implemented a physiologically-based control strategy that delivered different stimulation patterns through groups of electrodes to evoke walking movements with appropriate limb kinematics and forces corresponding to swing and stance. Each cat walked over an instrumented 2.9m walkway and limb kinematics and forces were recorded. Main Results Both propulsive and supportive forces were required for over-ground walking. Cumulative walking distances ranging from 609m to 835m (longest tested) were achieved in three animals. In these three cats, the mean peak supportive force was 3.5±0.6N corresponding to full-weight-support of the hind legs, while the angular range of the hip, knee, and ankle joints were 23.1±2.0°, 29.1±0.2°, and 60.3±5.2°, respectively. To further demonstrate the viability of ISMS for future clinical use, a prototype implantable module was successfully implemented in a subset of trials and produced comparable walking performance. Significance By activating inherent locomotor networks within the lumbosacral spinal cord, ISMS was capable of producing bilaterally coordinated and functional over-ground walking with current amplitudes <100 µA. These exciting results suggest that ISMS may be an effective intervention for restoring functional walking after

Analysis of walking variability through simultaneous evaluation of the head, lumbar, and lower-extremity acceleration in healthy youth

PubMed Central

Toda, Haruki; Nagano, Akinori; Luo, Zhiwei

2016-01-01

[Purpose] The purpose of this study was to clarify whether walking speed affects acceleration variability of the head, lumbar, and lower extremity by simultaneously evaluating of acceleration. [Subjects and Methods] Twenty young individuals recruited from among the staff at Kurashiki Heisei Hospital participated in this study. Eight accelerometers were used to measure the head, lumbar and lower extremity accelerations. The participants were instructed to walk at five walking speeds prescribed by a metronome. Acceleration variability was assessed by a cross-correlation analysis normalized using z-transform in order to evaluate stride-to-stride variability. [Results] Vertical acceleration variability was the smallest in all body parts, and walking speed effect had laterality. Antero-posterior acceleration variability was significantly associated with walking speed at sites other than the head. Medio-lateral acceleration variability of the bilateral hip alone was smaller than the antero-posterior variability. [Conclusion] The findings of this study suggest that the effect of walking speed changes on the stride-to-stride acceleration variability was individual for each body parts, and differs among directions. PMID:27390419

Lévy walks

NASA Astrophysics Data System (ADS)

Zaburdaev, V.; Denisov, S.; Klafter, J.

2015-04-01

Random walk is a fundamental concept with applications ranging from quantum physics to econometrics. Remarkably, one specific model of random walks appears to be ubiquitous across many fields as a tool to analyze transport phenomena in which the dispersal process is faster than dictated by Brownian diffusion. The Lévy-walk model combines two key features, the ability to generate anomalously fast diffusion and a finite velocity of a random walker. Recent results in optics, Hamiltonian chaos, cold atom dynamics, biophysics, and behavioral science demonstrate that this particular type of random walk provides significant insight into complex transport phenomena. This review gives a self-consistent introduction to Lévy walks, surveys their existing applications, including latest advances, and outlines further perspectives.

Effect of walking speed on lower extremity joint loading in graded ramp walking.

PubMed

Schwameder, Hermann; Lindenhofer, Elke; Müller, Erich

2005-07-01

Lower extremity joint loading during walking is strongly affected by the steepness of the slope and might cause pain and injuries in lower extremity joint structures. One feasible measure to reduce joint loading is the reduction of walking speed. Positive effects have been shown for level walking, but not for graded walking or hiking conditions. The aim of the study was to quantify the effect of walking speed (separated into the two components, step length and cadence) on the joint power of the hip, knee and ankle and to determine the knee joint forces in uphill and downhill walking. Ten participants walked up and down a ramp with step lengths of 0.46, 0.575 and 0.69 m and cadences of 80, 100 and 120 steps per minute. The ramp was equipped with a force platform and the locomotion was filmed with a 60 Hz video camera. Loading of the lower extremity joints was determined using inverse dynamics. A two-dimensional knee model was used to calculate forces in the knee structures during the stance phase. Walking speed affected lower extremity joint loading substantially and significantly. Change of step length caused much greater loading changes for all joints compared with change of cadence; the effects were more distinct in downhill than in uphill walking. The results indicate that lower extremity joint loading can be effectively controlled by varying step length and cadence during graded uphill and downhill walking. Hikers can avoid or reduce pain and injuries by reducing walking speed, particularly in downhill walking.

Rangi Ruru Walk: Social and Spatial Connections through Hybrid Intermedial Practices

ERIC Educational Resources Information Center

Wood, Becca; Mullen, Molly

2016-01-01

In 2013 Becca Wood, Spatial Performance Practitioner, and Molly Mullen, Applied Theatre Practitioner, collaborated to create a short ambulatory performance with audio score for a group of drama educators attending a conference workshop on the possibilities of walking as performance. The performance was created remotely from the intended site:…

Multiwavelength infrared focal plane array detector

NASA Technical Reports Server (NTRS)

Forrest, Stephen R. (Inventor); Olsen, Gregory H. (Inventor); Kim, Dong-Su (Inventor); Lange, Michael J. (Inventor)

1995-01-01

A multiwavelength focal plane array infrared detector is included on a common substrate having formed on its top face a plurality of In.sub.x Ga.sub.1-x As (x.ltoreq.0.53) absorption layers, between each pair of which a plurality of InAs.sub.y P.sub.1-y (y<1) buffer layers are formed having substantially increasing lattice parameters, respectively, relative to said substrate, for preventing lattice mismatch dislocations from propagating through successive ones of the absorption layers of decreasing bandgap relative to said substrate, whereby a plurality of detectors for detecting different wavelengths of light for a given pixel are provided by removing material above given areas of successive ones of the absorption layers, which areas are doped to form a pn junction with the surrounding unexposed portions of associated absorption layers, respectively, with metal contacts being formed on a portion of each of the exposed areas, and on the bottom of the substrate for facilitating electrical connections thereto.

Note: Reconfigurable pelvis mechanism for efficient multi-locomotion: Biped and quadruped walking

NASA Astrophysics Data System (ADS)

Yoon, Byungho; Kim, Soohyun

2017-12-01

A reconfigurable pelvis mechanism that can change its length for multi-locomotion robot is introduced. From the characteristics of animals that walk in a bipedal or quadrupedal manner, we found that the length of the pelvis for each type of locomotion is related to the efficiency and stability of walking. We demonstrated the effectiveness of this mechanism in biped and quadruped walking through comparison of accumulated power of consumption. We also examined the changes of the supporting polygon according to the length of the pelvis during quadruped walking in terms of stability.

Note: Reconfigurable pelvis mechanism for efficient multi-locomotion: Biped and quadruped walking.

PubMed

Yoon, Byungho; Kim, Soohyun

2017-12-01

A reconfigurable pelvis mechanism that can change its length for multi-locomotion robot is introduced. From the characteristics of animals that walk in a bipedal or quadrupedal manner, we found that the length of the pelvis for each type of locomotion is related to the efficiency and stability of walking. We demonstrated the effectiveness of this mechanism in biped and quadruped walking through comparison of accumulated power of consumption. We also examined the changes of the supporting polygon according to the length of the pelvis during quadruped walking in terms of stability.

Thermal response of solar receiver aperture plates during sun walk-off

NASA Technical Reports Server (NTRS)

Wen, L.; Roschke, J.

1982-01-01

The tracking mechanism for a point-focusing concentrator may be subject to failure. If this should occur, the solar image will travel across the aperture plate, and it may also impinge on the adjacent support structure. Such an event is called 'sun walk-off'. The present investigation is concerned with the transient response of different aperture plate materials to the intense heating produced in a typical walk-off situation for parabolic dish concentrators. Receivers for two solar module systems are considered, including a high-temperature receiver that utilizes a 2-milliradian (mrad) concentrator, and a lower-temperature receiver which is coupled with a 4-mrad concentrator. It is found that during a walk-off situation the solar image travels in a straight line in the radial direction. The results obtained for a copper aperture plate were disappointing. It appears that passive metallic plates without cooling or other protective support cannot withstand the intense heating.

Adults' Daily Walking for Travel and Leisure: Interaction Between Attitude Toward Walking and the Neighborhood Environment.

PubMed

Yang, Yong; Diez-Roux, Ana V

2017-09-01

Studies on how the interaction of psychological and environmental characteristics influences walking are limited, and the results are inconsistent. Our aim is to examine how the attitude toward walking and neighborhood environments interacts to influence walking. Cross-sectional phone and mail survey. Participants randomly sampled from 6 study sites including Los Angeles, Chicago, Baltimore, Minneapolis, Manhattan, and Bronx Counties in New York City, and Forsyth and Davidson Counties in North Carolina. The final sample consisted of 2621 persons from 2011 to 2012. Total minutes of walking for travel or leisure, attitude toward walking, and perceptions of the neighborhood environments were self-reported. Street Smart (SS) Walk Score (a measure of walkability derived from a variety of geographic data) was obtained for each residential location. Linear regression models adjusting for age, gender, race/ethnicity, education, and income. Attitude toward walking was positively associated with walking for both purposes. Walking for travel was significantly associated with SS Walk Score, whereas walking for leisure was not. The SS Walk Score and selected perceived environment characteristics were associated with walking in people with a very positive attitude toward walking but were not associated with walking in people with a less positive attitude. Attitudes toward walking and neighborhood environments interact to affect walking behavior.

Effects of a Flexibility and Relaxation Programme, Walking, and Nordic Walking on Parkinson's Disease

PubMed Central

Reuter, I.; Mehnert, S.; Leone, P.; Kaps, M.; Oechsner, M.; Engelhardt, M.

2011-01-01

Symptoms of Parkinson's disease (PD) progress despite optimized medical treatment. The present study investigated the effects of a flexibility and relaxation programme, walking, and Nordic walking (NW) on walking speed, stride length, stride length variability, Parkinson-specific disability (UPDRS), and health-related quality of life (PDQ 39). 90 PD patients were randomly allocated to the 3 treatment groups. Patients participated in a 6-month study with 3 exercise sessions per week, each lasting 70 min. Assessment after completion of the training showed that pain was reduced in all groups, and balance and health-related quality of life were improved. Furthermore, walking, and Nordic walking improved stride length, gait variability, maximal walking speed, exercise capacity at submaximal level, and PD disease-specific disability on the UPDRS in addition. Nordic walking was superior to the flexibility and relaxation programme and walking in improving postural stability, stride length, gait pattern and gait variability. No significant injuries occurred during the training. All patients of the Nordic walking group continued Nordic walking after completing the study. PMID:21603199

A plasmonic nanorod that walks on DNA origami

PubMed Central

Zhou, Chao; Duan, Xiaoyang; Liu, Na

2015-01-01

In nano-optics, a formidable challenge remains in precise transport of a single optical nano-object along a programmed and routed path toward a predefined destination. Molecular motors in living cells that can walk directionally along microtubules have been the inspiration for realizing artificial molecular walkers. Here we demonstrate an active plasmonic system, in which a plasmonic nanorod can execute directional, progressive and reverse nanoscale walking on two or three-dimensional DNA origami. Such a walker comprises an anisotropic gold nanorod as its ‘body' and discrete DNA strands as its ‘feet'. Specifically, our walker carries optical information and can in situ optically report its own walking directions and consecutive steps at nanometer accuracy, through dynamic coupling to a plasmonic stator immobilized along its walking track. Our concept will enable a variety of smart nanophotonic platforms for studying dynamic light–matter interaction, which requires controlled motion at the nanoscale well below the optical diffraction limit. PMID:26303016

Method for producing a hybridization of detector array and integrated circuit for readout

NASA Technical Reports Server (NTRS)

Fossum, Eric R. (Inventor); Grunthaner, Frank J. (Inventor)

1993-01-01

A process is explained for fabricating a detector array in a layer of semiconductor material on one substrate and an integrated readout circuit in a layer of semiconductor material on a separate substrate in order to select semiconductor material for optimum performance of each structure, such as GaAs for the detector array and Si for the integrated readout circuit. The detector array layer is lifted off its substrate, laminated on the metallized surface on the integrated surface, etched with reticulating channels to the surface of the integrated circuit, and provided with interconnections between the detector array pixels and the integrated readout circuit through the channels. The adhesive material for the lamination is selected to be chemically stable to provide electrical and thermal insulation and to provide stress release between the two structures fabricated in semiconductor materials that may have different coefficients of thermal expansion.

29 CFR 1910.26 - Portable metal ladders.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR OCCUPATIONAL SAFETY AND HEALTH STANDARDS Walking-Working Surfaces § 1910.26 Portable metal ladders. (a... material for the safety of the user. (viii) A metal spreader or locking device of sufficient size and...

Quantum walk computation

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

Kendon, Viv

2014-12-04

Quantum versions of random walks have diverse applications that are motivating experimental implementations as well as theoretical studies. Recent results showing quantum walks are “universal for quantum computation” relate to algorithms, to be run on quantum computers. We consider whether an experimental implementation of a quantum walk could provide useful computation before we have a universal quantum computer.

Adaptation mechanism of interlimb coordination in human split-belt treadmill walking through learning of foot contact timing: a robotics study

PubMed Central

Fujiki, Soichiro; Aoi, Shinya; Funato, Tetsuro; Tomita, Nozomi; Senda, Kei; Tsuchiya, Kazuo

2015-01-01

Human walking behaviour adaptation strategies have previously been examined using split-belt treadmills, which have two parallel independently controlled belts. In such human split-belt treadmill walking, two types of adaptations have been identified: early and late. Early-type adaptations appear as rapid changes in interlimb and intralimb coordination activities when the belt speeds of the treadmill change between tied (same speed for both belts) and split-belt (different speeds for each belt) configurations. By contrast, late-type adaptations occur after the early-type adaptations as a gradual change and only involve interlimb coordination. Furthermore, interlimb coordination shows after-effects that are related to these adaptations. It has been suggested that these adaptations are governed primarily by the spinal cord and cerebellum, but the underlying mechanism remains unclear. Because various physiological findings suggest that foot contact timing is crucial to adaptive locomotion, this paper reports on the development of a two-layered control model for walking composed of spinal and cerebellar models, and on its use as the focus of our control model. The spinal model generates rhythmic motor commands using an oscillator network based on a central pattern generator and modulates the commands formulated in immediate response to foot contact, while the cerebellar model modifies motor commands through learning based on error information related to differences between the predicted and actual foot contact timings of each leg. We investigated adaptive behaviour and its mechanism by split-belt treadmill walking experiments using both computer simulations and an experimental bipedal robot. Our results showed that the robot exhibited rapid changes in interlimb and intralimb coordination that were similar to the early-type adaptations observed in humans. In addition, despite the lack of direct interlimb coordination control, gradual changes and after-effects in the

Adaptation mechanism of interlimb coordination in human split-belt treadmill walking through learning of foot contact timing: a robotics study.

PubMed

Fujiki, Soichiro; Aoi, Shinya; Funato, Tetsuro; Tomita, Nozomi; Senda, Kei; Tsuchiya, Kazuo

2015-09-06

Human walking behaviour adaptation strategies have previously been examined using split-belt treadmills, which have two parallel independently controlled belts. In such human split-belt treadmill walking, two types of adaptations have been identified: early and late. Early-type adaptations appear as rapid changes in interlimb and intralimb coordination activities when the belt speeds of the treadmill change between tied (same speed for both belts) and split-belt (different speeds for each belt) configurations. By contrast, late-type adaptations occur after the early-type adaptations as a gradual change and only involve interlimb coordination. Furthermore, interlimb coordination shows after-effects that are related to these adaptations. It has been suggested that these adaptations are governed primarily by the spinal cord and cerebellum, but the underlying mechanism remains unclear. Because various physiological findings suggest that foot contact timing is crucial to adaptive locomotion, this paper reports on the development of a two-layered control model for walking composed of spinal and cerebellar models, and on its use as the focus of our control model. The spinal model generates rhythmic motor commands using an oscillator network based on a central pattern generator and modulates the commands formulated in immediate response to foot contact, while the cerebellar model modifies motor commands through learning based on error information related to differences between the predicted and actual foot contact timings of each leg. We investigated adaptive behaviour and its mechanism by split-belt treadmill walking experiments using both computer simulations and an experimental bipedal robot. Our results showed that the robot exhibited rapid changes in interlimb and intralimb coordination that were similar to the early-type adaptations observed in humans. In addition, despite the lack of direct interlimb coordination control, gradual changes and after-effects in the

Association between reliance on devices and people for walking and ability to walk community distances among persons with spinal cord injury.

PubMed

Brotherton, Sandra S; Saunders, Lee L; Krause, James S; Morrisette, David C

2012-05-01

To identify and describe the frequency of reliance on assistive devices and/or people for ambulating distances and stair climbing. Survey. A total of 429 adults with traumatic spinal cord injury who were able to walk at least 10 m were identified through inpatient and outpatient hospital databases at a specialty hospital in the southeast United States. Data were collected using a self-report questionnaire including items related to distances walked and devices used for ambulation. Participants best able to ambulate community distances were those who were independent with ambulation and those who used one cane or crutch. Reliance on people or use of a walker was associated with walking shorter distances. Regression analysis indicated reliance on devices or people for walking predicted variation in ability to ambulate community distances after controlling for demographic and injury characteristics. This study suggests that reliance on devices or a person for assistance is important to consider when assessing potential for achieving functional community ambulation.

A walk through the heavens : a guide to stars and constellations and their legends

NASA Astrophysics Data System (ADS)

Heifetz, Milton D.; Tirion, Wil

What star is that? Where's the Great Bear? Who was Andromeda? A Walk through the Heavens is your guide to the pathways of the night sky, answering the commonest questions about what you can see up there. There are simplified maps of the constellations, together with instructions on how to gauge their sizes and the distances between them. With this information you can find the constellations easily, and make a journey by eye from one constellation to the next. Ancient myths surrounding the constellations are retold, enriching our understanding of how historical peoples saw the awe-inspiring spectacle of a sky sprinkled with stars. This book, magically illustrated by Wil Tirion, does not require any instrument or telescope. It is an ideal introduction to launch a young astronomer on a journey across starlit skies.

Graphic matching based on shape contexts and reweighted random walks

NASA Astrophysics Data System (ADS)

Zhang, Mingxuan; Niu, Dongmei; Zhao, Xiuyang; Liu, Mingjun

2018-04-01

Graphic matching is a very critical issue in all aspects of computer vision. In this paper, a new graphics matching algorithm combining shape contexts and reweighted random walks was proposed. On the basis of the local descriptor, shape contexts, the reweighted random walks algorithm was modified to possess stronger robustness and correctness in the final result. Our main process is to use the descriptor of the shape contexts for the random walk on the iteration, of which purpose is to control the random walk probability matrix. We calculate bias matrix by using descriptors and then in the iteration we use it to enhance random walks' and random jumps' accuracy, finally we get the one-to-one registration result by discretization of the matrix. The algorithm not only preserves the noise robustness of reweighted random walks but also possesses the rotation, translation, scale invariance of shape contexts. Through extensive experiments, based on real images and random synthetic point sets, and comparisons with other algorithms, it is confirmed that this new method can produce excellent results in graphic matching.

Industrial hygiene walk-through survey report of BASF Corporation - Inmont Division, Cincinnati, Ohio

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

McCammon, C.S.; Krishnan, E.R.; Goodman, R.J.

The potential for employee exposure to acrylates or methacrylates was investigated by a walk-through industrial-hygiene survey at the Inmont facility of BASF Corporation, Cincinnati, Ohio. Radiation-curable coatings and ink vehicles have been produced at this facility for the previous 7 years. Coatings are formulated in a mixing tank with a high-speed agitator. Two enclosed reactors were used to formulate the ink vehicles. The work force is composed of 205 employees, 41 of whom function in areas where exposure to the suspect chemicals is likely. No industrial hygiene data for multifunctional acrylates had been collected and no illnesses attributable to themore » chemicals have been reported at the facility. There is a structured medical program at the facility with a safety program and a general industrial-hygiene program. Adequate personnel records were have been kept for all employees. No recommendations were considered necessary.« less

Analysis of periodically patterned metallic nanostructures for infrared absorber

NASA Astrophysics Data System (ADS)

Peng, Sha; Yuan, Ying; Long, Huabao; Liu, Runhan; Wei, Dong; Zhang, Xinyu; Wang, Haiwei; Xie, Changsheng

2018-02-01

With rapid advancement of infrared detecting technology in both military and civil domains, the photo-electronic performances of near-infrared detectors have been widely concerned. Currently, near-infrared detectors demonstrate some problems such as low sensitivity, low detectivity, and relatively small array scale. The current studies show that surface plasmons (SPs) stimulated over the surface of metallic nanostructures by incident light can be used to break the diffraction limit and thus concentrate light into sub-wavelength scale, so as to indicate a method to develop a new type of infrared absorber or detector with very large array. In this paper, we present the design and characterization of periodically patterned metallic nanostructures that combine nanometer thickness aluminum film with silicon wafer. Numerical computations show that there are some valleys caused by surface plasmons in the reflection spectrum in the infrared region, and both red shift and blue shift of the reflection spectrum were observed through changing the nanostructural parameters such as angle α and diameters D. Moreover, the strong E-field intensity is located at the sharp corner of the nano-structures.

Origins of ultralow velocity zones through slab-derived metallic melt

PubMed Central

Liu, Jiachao; Li, Jie; Smith, Jesse S.

2016-01-01

Understanding the ultralow velocity zones (ULVZs) places constraints on the chemical composition and thermal structure of deep Earth and provides critical information on the dynamics of large-scale mantle convection, but their origin has remained enigmatic for decades. Recent studies suggest that metallic iron and carbon are produced in subducted slabs when they sink beyond a depth of 250 km. Here we show that the eutectic melting curve of the iron−carbon system crosses the current geotherm near Earth’s core−mantle boundary, suggesting that dense metallic melt may form in the lowermost mantle. If concentrated into isolated patches, such melt could produce the seismically observed density and velocity features of ULVZs. Depending on the wetting behavior of the metallic melt, the resultant ULVZs may be short-lived domains that are replenished or regenerated through subduction, or long-lasting regions containing both metallic and silicate melts. Slab-derived metallic melt may produce another type of ULVZ that escapes core sequestration by reacting with the mantle to form iron-rich postbridgmanite or ferropericlase. The hypotheses connect peculiar features near Earth's core−mantle boundary to subduction of the oceanic lithosphere through the deep carbon cycle. PMID:27143719

Hole-Impeded-Doping-Superlattice LWIR Detectors

NASA Technical Reports Server (NTRS)

Maserjian, Joseph

1991-01-01

Hole-Impeded-Doping-Superlattice (HIDS) InAs devices proposed for use as photoconductive or photovoltaic detectors of radiation in long-wavelength infrared (LWIR) range of 8 to 17 micrometers. Array of HIDS devices fabricated on substrates GaAs or Si. Radiation incident on black surface, metal contacts for picture elements serve as reactors, effectively doubling optical path and thereby increasing absorption of photons. Photoconductive detector offers advantages of high gain and high impedance; photovoltaic detector offers lower noise and better interface to multiplexer readouts.

Lab-based x-ray tomography of a cochlear implant using energy discriminating detectors for metal artefact reduction

NASA Astrophysics Data System (ADS)

Yokhana, Viona S. K.; Arhatari, Benedicta D.; Gureyev, Timur E.; Abbey, Brian

2018-01-01

X-ray computed tomography (XCT) is an important clinical diagnostic tool which is also used in a range of biological imaging applications in research. The increasing prevalence of metallic implants in medical and dental radiography and tomography has driven the demand for new approaches to solving the issue of metal artefacts in XCT. Metal artefacts occur when a highly absorbing material is imaged which is in boundary contact with one or more weakly absorbing components, such as soft-tissue. The resulting `streaking' in the reconstructed images creates significant challenges for X-ray analysis due to the non-linear dependence on the absorption properties of the sample. In this paper we introduce a new approach to removing metal artefacts which exploits the capabilities of the recently available, photon-counting PiXirad detector. Our approach works for standard lab-based polychromatic X-ray tubes and does not rely on any postprocessing of the data. The method is demonstrated using both simulated data from a test phantom and experimental data collected from a cochlear implant. The results show that by combining the individual images, which are simultaneously generated for each different energy threshold, artefact -free segmentation of the implant from the surrounding biological tissue is achieved.

Heightening Walking Above its Pedestrian Status : Walking and Travel Behavior in California

DOT National Transportation Integrated Search

2016-06-30

People walk a lotto walk pets, to exercise and recreate, and to access public transit and local shops. Walk trips begin and end almost every journey, even trips made by automobile. Data from the current California Household Travel Survey (CHTS) sh...

Walk Score® and Transit Score® and Walking in the Multi-Ethnic Study of Atherosclerosis

PubMed Central

Hirsch, Jana A.; Moore, Kari A.; Evenson, Kelly R.; Rodriguez, Daniel A; Diez Roux, Ana V.

2013-01-01

Background Walk Score® and Transit Score® are open-source measures of the neighborhood built environment to support walking (“walkability”) and access to transportation. Purpose To investigate associations of Street Smart Walk Score and Transit Score with self-reported transport and leisure walking using data from a large multi-city and diverse population-based sample of adults. Methods Data from a sample of 4552 residents of Baltimore MD; Chicago IL; Forsyth County NC; Los Angeles CA; New York NY; and St. Paul MN from the Multi-Ethnic Study of Atherosclerosis (2010–2012) were linked to Walk Score and Transit Score (collected in 2012). Logistic and linear regression models estimated ORs of not walking and mean differences in minutes walked, respectively, associated with continuous and categoric Walk Score and Transit Score. All analyses were conducted in 2012. Results After adjustment for site, key sociodemographic, and health variables, a higher Walk Score was associated with lower odds of not walking for transport and more minutes/week of transport walking. Compared to those in a “walker’s paradise,” lower categories of Walk Score were associated with a linear increase in odds of not transport walking and a decline in minutes of leisure walking. An increase in Transit Score was associated with lower odds of not transport walking or leisure walking, and additional minutes/week of leisure walking. Conclusions Walk Score and Transit Score appear to be useful as measures of walkability in analyses of neighborhood effects. PMID:23867022

Generalized teleportation by quantum walks

NASA Astrophysics Data System (ADS)

Wang, Yu; Shang, Yun; Xue, Peng

2017-09-01

We develop a generalized teleportation scheme based on quantum walks with two coins. For an unknown qubit state, we use two-step quantum walks on the line and quantum walks on the cycle with four vertices for teleportation. For any d-dimensional states, quantum walks on complete graphs and quantum walks on d-regular graphs can be used for implementing teleportation. Compared with existing d-dimensional states teleportation, prior entangled state is not required and the necessary maximal entanglement resource is generated by the first step of quantum walk. Moreover, two projective measurements with d elements are needed by quantum walks on the complete graph, rather than one joint measurement with d^2 basis states. Quantum walks have many applications in quantum computation and quantum simulations. This is the first scheme of realizing communicating protocol with quantum walks, thus opening wider applications.

Walking economy during cued versus non-cued self-selected treadmill walking in persons with Parkinson's disease.

PubMed

Gallo, Paul M; McIsaac, Tara L; Garber, Carol Ewing

2014-01-01

Gait impairments related to Parkinson's disease (PD) include variable step length and decreased walking velocity, which may result in poorer walking economy. Auditory cueing is a common method used to improve gait mechanics in PD that has been shown to worsen walking economy at set treadmill walking speeds. It is unknown if auditory cueing has the same effects on walking economy at self-selected treadmill walking speeds. To determine if auditory cueing will affect walking economy at self-selected treadmill walking speeds and at speeds slightly faster and slower than self-selected. Twenty-two participants with moderate PD performed three, 6-minute bouts of treadmill walking at three speeds (self-selected and ± 0.22 m·sec-1). One session used cueing and the other without cueing. Energy expenditure was measured and walking economy was calculated (energy expenditure/power). Poorer walking economy and higher energy expenditure occurred during cued walking at a self-selected and a slightly faster walking speed, but there was no apparent difference at the slightly slower speed. These results suggest that potential gait benefits of auditory cueing may come at an energy cost and poorer walking economy for persons with PD at least at some treadmill walking speeds.

Force Rendering and its Evaluation of a Friction-Based Walking Sensation Display for a Seated User.

PubMed

Kato, Ginga; Kuroda, Yoshihiro; Kiyokawa, Kiyoshi; Takemura, Haruo

2018-04-01

Most existing locomotion devices that represent the sensation of walking target a user who is actually performing a walking motion. Here, we attempted to represent the walking sensation, especially a kinesthetic sensation and advancing feeling (the sense of moving forward) while the user remains seated. To represent the walking sensation using a relatively simple device, we focused on the force rendering and its evaluation of the longitudinal friction force applied on the sole during walking. Based on the measurement of the friction force applied on the sole during actual walking, we developed a novel friction force display that can present the friction force without the influence of body weight. Using performance evaluation testing, we found that the proposed method can stably and rapidly display friction force. Also, we developed a virtual reality (VR) walk-through system that is able to present the friction force through the proposed device according to the avatar's walking motion in a virtual world. By evaluating the realism, we found that the proposed device can represent a more realistic advancing feeling than vibration feedback.

The Relationship Between Objectively Measured Walking and Risk of Pedestrian–Motor Vehicle Collision

PubMed Central

Quistberg, D. Alex; Howard, Eric J.; Hurvitz, Philip M.; Moudon, Anne V.; Ebel, Beth E.; Rivara, Frederick P.; Saelens, Brian E.

2017-01-01

Abstract Safe urban walking environments may improve health by encouraging physical activity, but the relationship between an individual's location and walking pattern and the risk of pedestrian–motor vehicle collision is unknown. We examined associations between individuals’ walking bouts and walking risk, measured as mean exposure to the risk of pedestrian-vehicle collision. Walking bouts were ascertained through integrated accelerometry and global positioning system data and from individual travel-diary data obtained from adults in the Travel Assessment and Community Study (King County, Washington) in 2008–2009. Walking patterns were superimposed onto maps of the historical probabilities of pedestrian-vehicle collisions for intersections and midblock segments within Seattle, Washington. Mean risk of pedestrian-vehicle collision in specific walking locations was assessed according to walking exposure (duration, distance, and intensity) and participant demographic characteristics in linear mixed models. Participants typically walked in areas with low pedestrian collision risk when walking for recreation, walking at a faster pace, or taking longer-duration walks. Mean daily walking duration and distance were not associated with collision risk. Males walked in areas with higher collision risk compared with females, while vehicle owners, residents of single-family homes, and parents of young children walked in areas with lower collision risk. These findings may suggest that pedestrians moderate collision risk by using lower-risk routes. PMID:28338921

Daily intermittent hypoxia enhances walking after chronic spinal cord injury

PubMed Central

Hayes, Heather B.; Jayaraman, Arun; Herrmann, Megan; Mitchell, Gordon S.; Rymer, William Z.

2014-01-01

Objectives: To test the hypothesis that daily acute intermittent hypoxia (dAIH) and dAIH combined with overground walking improve walking speed and endurance in persons with chronic incomplete spinal cord injury (iSCI). Methods: Nineteen subjects completed the randomized, double-blind, placebo-controlled, crossover study. Participants received 15, 90-second hypoxic exposures (dAIH, fraction of inspired oxygen [Fio2] = 0.09) or daily normoxia (dSHAM, Fio2 = 0.21) at 60-second normoxic intervals on 5 consecutive days; dAIH was given alone or combined with 30 minutes of overground walking 1 hour later. Walking speed and endurance were quantified using 10-Meter and 6-Minute Walk Tests. The trial is registered at ClinicalTrials.gov (NCT01272349). Results: dAIH improved walking speed and endurance. Ten-Meter Walk time improved with dAIH vs dSHAM after 1 day (mean difference [MD] 3.8 seconds, 95% confidence interval [CI] 1.1–6.5 seconds, p = 0.006) and 2 weeks (MD 3.8 seconds, 95% CI 0.9–6.7 seconds, p = 0.010). Six-Minute Walk distance increased with combined dAIH + walking vs dSHAM + walking after 5 days (MD 94.4 m, 95% CI 17.5–171.3 m, p = 0.017) and 1-week follow-up (MD 97.0 m, 95% CI 20.1–173.9 m, p = 0.014). dAIH + walking increased walking distance more than dAIH after 1 day (MD 67.7 m, 95% CI 1.3–134.1 m, p = 0.046), 5 days (MD 107.0 m, 95% CI 40.6–173.4 m, p = 0.002), and 1-week follow-up (MD 136.0 m, 95% CI 65.3–206.6 m, p < 0.001). Conclusions: dAIH ± walking improved walking speed and distance in persons with chronic iSCI. The impact of dAIH is enhanced by combination with walking, demonstrating that combinatorial therapies may promote greater functional benefits in persons with iSCI. Classification of evidence: This study provides Class I evidence that transient hypoxia (through measured breathing treatments), along with overground walking training, improves walking speed and endurance after iSCI. PMID:24285617

Comparison of two 6-minute walk tests to assess walking capacity in polio survivors.

PubMed

Brehm, Merel-Anne; Verduijn, Suzan; Bon, Jurgen; Bredt, Nicoline; Nollet, Frans

2017-11-21

To compare walking dynamics and test-retest reliability for 2 frequently applied walk tests in polio survivors: the 6-minute walk test (6MWT) to walk as far as possible; and the 6-minute walking energy cost test (WECT) at comfortable speed. Observational study. Thirty-three polio survivors, able to walk ≥ 150 m. On the same day participants performed a 6MWT and a WECT, which were repeated 1-3 weeks later. For each test, distance walked, heart rate and reduction in speed were assessed. The mean distance walked and mean heart rate were significantly higher in the 6MWT (441 m (standard deviation) (SD 79.7); 118 bpm (SD 19.2)) compared with the WECT (366 m (SD 67.3); 103 bpm (SD 14.3)); p< 0.001. Furthermore, during the 6MWT, patients continuously slowed down (-6%), while during the WECT speed dropped only slightly during the first 2 min, by -1.8% in total. Test-retest reliability of both tests was excellent (intraclass correlation coefficient (ICC) ≥ 0.95; lower bound 95% confidence interval (95% CI) ≥ 0.87). The smallest detectable change for the walked distance was 42 m (9.7% change from the mean) and 50 m (13.7%) on the 6MWT and WECT, respectively. Both the 6MWT and the WECT are reliable to assess walking capacity in polio survivors, with slightly superior sensitivity to detect change for the 6MWT. Differences in walking dynamics confirm that the tests cannot be used interchangeably. The 6MWT is recommended for measuring maximal walking capacity and the WECT for measuring submaximal walking capacity.

Thin-film ultraviolet detector and spectrometer

NASA Technical Reports Server (NTRS)

Lewicki, G. W.; Maserjian, J.

1972-01-01

Typical metal-insulator-metal detector device is formed on quartz substrate. Base electrode is 3 to 6 nm aluminum layer, overcoated with 3 to 6 nm aluminum oxide or aluminum nitride, and capped with counter electrode of gold, lead, magnesium, or aluminum. Photoelectric yield data are given for Al-AlN-Au structure.

Walking behavior on Lapangan Merdeka district in Medan city

NASA Astrophysics Data System (ADS)

Zahrah, W.; Mandai, A. J. O.; Nasution, A. D.

2018-03-01

Lapangan Merdeka district in Medan City is an area with a lot of functions and activities. Pedestrians in this area pose particular behavior for walking. Such behavior can be formed due to certain factors. This study aimed to identify the behavior and motivation of walking, as well as knowing the perception of pedestrians on pedestrian facilities and infrastructures. This research is a qualitative descriptive study. This research was conducted in five streets that have pedestrian lanes by collecting data through observation of pedestrian facilities and infrastructures, as well as the distribution of questionnaires to investigate the characteristics of pedestrians, the behavior and motivation of walking, and perceptions of pedestrian facilities and infrastructure. The research found that the behavior of pedestrians when walking are different on certain characteristics of pedestrians as well as the specific conditions of facilities and infrastructures. The most dominant motivation when walking in this area is easy transportation access. The results of the perception of pedestrians also show that pedestrian facilities and infrastructure are good in this area.

A New Random Walk for Replica Detection in WSNs

PubMed Central

Aalsalem, Mohammed Y.; Saad, N. M.; Hossain, Md. Shohrab; Atiquzzaman, Mohammed; Khan, Muhammad Khurram

2016-01-01

Wireless Sensor Networks (WSNs) are vulnerable to Node Replication attacks or Clone attacks. Among all the existing clone detection protocols in WSNs, RAWL shows the most promising results by employing Simple Random Walk (SRW). More recently, RAND outperforms RAWL by incorporating Network Division with SRW. Both RAND and RAWL have used SRW for random selection of witness nodes which is problematic because of frequently revisiting the previously passed nodes that leads to longer delays, high expenditures of energy with lower probability that witness nodes intersect. To circumvent this problem, we propose to employ a new kind of constrained random walk, namely Single Stage Memory Random Walk and present a distributed technique called SSRWND (Single Stage Memory Random Walk with Network Division). In SSRWND, single stage memory random walk is combined with network division aiming to decrease the communication and memory costs while keeping the detection probability higher. Through intensive simulations it is verified that SSRWND guarantees higher witness node security with moderate communication and memory overheads. SSRWND is expedient for security oriented application fields of WSNs like military and medical. PMID:27409082

A New Random Walk for Replica Detection in WSNs.

PubMed

Aalsalem, Mohammed Y; Khan, Wazir Zada; Saad, N M; Hossain, Md Shohrab; Atiquzzaman, Mohammed; Khan, Muhammad Khurram

2016-01-01

Wireless Sensor Networks (WSNs) are vulnerable to Node Replication attacks or Clone attacks. Among all the existing clone detection protocols in WSNs, RAWL shows the most promising results by employing Simple Random Walk (SRW). More recently, RAND outperforms RAWL by incorporating Network Division with SRW. Both RAND and RAWL have used SRW for random selection of witness nodes which is problematic because of frequently revisiting the previously passed nodes that leads to longer delays, high expenditures of energy with lower probability that witness nodes intersect. To circumvent this problem, we propose to employ a new kind of constrained random walk, namely Single Stage Memory Random Walk and present a distributed technique called SSRWND (Single Stage Memory Random Walk with Network Division). In SSRWND, single stage memory random walk is combined with network division aiming to decrease the communication and memory costs while keeping the detection probability higher. Through intensive simulations it is verified that SSRWND guarantees higher witness node security with moderate communication and memory overheads. SSRWND is expedient for security oriented application fields of WSNs like military and medical.

Estimation of detection thresholds for redirected walking techniques.

PubMed

Steinicke, Frank; Bruder, Gerd; Jerald, Jason; Frenz, Harald; Lappe, Markus

2010-01-01

In immersive virtual environments (IVEs), users can control their virtual viewpoint by moving their tracked head and walking through the real world. Usually, movements in the real world are mapped one-to-one to virtual camera motions. With redirection techniques, the virtual camera is manipulated by applying gains to user motion so that the virtual world moves differently than the real world. Thus, users can walk through large-scale IVEs while physically remaining in a reasonably small workspace. In psychophysical experiments with a two-alternative forced-choice task, we have quantified how much humans can unknowingly be redirected on physical paths that are different from the visually perceived paths. We tested 12 subjects in three different experiments: (E1) discrimination between virtual and physical rotations, (E2) discrimination between virtual and physical straightforward movements, and (E3) discrimination of path curvature. In experiment E1, subjects performed rotations with different gains, and then had to choose whether the visually perceived rotation was smaller or greater than the physical rotation. In experiment E2, subjects chose whether the physical walk was shorter or longer than the visually perceived scaled travel distance. In experiment E3, subjects estimate the path curvature when walking a curved path in the real world while the visual display shows a straight path in the virtual world. Our results show that users can be turned physically about 49 percent more or 20 percent less than the perceived virtual rotation, distances can be downscaled by 14 percent and upscaled by 26 percent, and users can be redirected on a circular arc with a radius greater than 22 m while they believe that they are walking straight.

Understanding the detector behavior through Montecarlo and calibration studies in view of the SOX measurement

NASA Astrophysics Data System (ADS)

Caminata, A.; Agostini, M.; Altenmüller, K.; Appel, S.; Bellini, G.; Benziger, J.; Berton, N.; Bick, D.; Bonfini, G.; Bravo, D.; Caccianiga, B.; Calaprice, F.; Cavalcante, P.; Chepurnov, A.; Choi, K.; Cribier, M.; D'Angelo, D.; Davini, S.; Derbin, A.; Di Noto, L.; Drachnev, I.; Durero, M.; Empl, A.; Etenko, A.; Farinon, S.; Fischer, V.; Fomenko, K.; Franco, D.; Gabriele, F.; Gaffiot, J.; Galbiati, C.; Ghiano, C.; Giammarchi, M.; Goeger-Neff, M.; Goretti, A.; Gromov, M.; Hagner, C.; Houdy, T.; Hungerford, E.; Ianni, Aldo; Ianni, Andrea; Jonquères, N.; Jedrzejczak, K.; Kaiser, M.; Kobychev, V.; Korablev, D.; Korga, G.; Kornoukhov, V.; Kryn, D.; Lachenmaier, T.; Lasserre, T.; Laubenstein, M.; Lehnert, B.; Link, J.; Litvinovich, E.; Lombardi, F.; Lombardi, P.; Ludhova, L.; Lukyanchenko, G.; Machulin, I.; Manecki, S.; Maneschg, W.; Marcocci, S.; Maricic, J.; Mention, G.; Meroni, E.; Meyer, M.; Miramonti, L.; Misiaszek, M.; Montuschi, M.; Mosteiro, P.; Muratova, V.; Musenich, R.; Neumair, B.; Oberauer, L.; Obolensky, M.; Ortica, F.; Pallavicini, M.; Papp, L.; Perasso, L.; Pocar, A.; Ranucci, G.; Razeto, A.; Re, A.; Romani, A.; Roncin, R.; Rossi, N.; Schönert, S.; Scola, L.; Semenov, D.; Simgen, H.; Skorokhvatov, M.; Smirnov, O.; Sotnikov, A.; Sukhotin, S.; Suvorov, Y.; Tartaglia, R.; Testera, G.; Thurn, J.; Toropova, M.; Unzhakov, E.; Veyssiere, C.; Vishneva, A.; Vivier, M.; Vogelaar, R. B.; von Feilitzsch, F.; Wang, H.; Weinz, S.; Winter, J.; Wojcik, M.; Wurm, M.; Yokley, Z.; Zaimidoroga, O.; Zavatarelli, S.; Zuber, K.; Zuzel, G.

2016-02-01

Borexino is an unsegmented neutrino detector operating at LNGS in central Italy. The experiment has shown its performances through its unprecedented accomplishments in the solar and geoneutrino detection. These performances make it an ideal tool to accomplish a state- of-the-art experiment able to test the existence of sterile neutrinos (SOX experiment). For both the solar and the SOX analysis, a good understanding of the detector response is fundamental. Consequently, calibration campaigns with radioactive sources have been performed over the years. The calibration data are of extreme importance to develop an accurate Monte Carlo code. This code is used in all the neutrino analyses. The Borexino-SOX calibration techniques and program and the advances on the detector simulation code in view of the start of the SOX data taking are presented. 1

Seeing tobacco mosaic virus through direct electron detectors

PubMed Central

Fromm, Simon A.; Bharat, Tanmay A.M.; Jakobi, Arjen J.; Hagen, Wim J.H.; Sachse, Carsten

2015-01-01

With the introduction of direct electron detectors (DED) to the field of electron cryo-microscopy, a wave of atomic-resolution structures has become available. As the new detectors still require comparative characterization, we have used tobacco mosaic virus (TMV) as a test specimen to study the quality of 3D image reconstructions from data recorded on the two direct electron detector cameras, K2 Summit and Falcon II. Using DED movie frames, we explored related image-processing aspects and compared the performance of micrograph-based and segment-based motion correction approaches. In addition, we investigated the effect of dose deposition on the atomic-resolution structure of TMV and show that radiation damage affects negative carboxyl chains first in a side-chain specific manner. Finally, using 450,000 asymmetric units and limiting the effects of radiation damage, we determined a high-resolution cryo-EM map at 3.35 Å resolution. Here, we provide a comparative case study of highly ordered TMV recorded on different direct electron detectors to establish recording and processing conditions that enable structure determination up to 3.2 Å in resolution using cryo-EM. PMID:25528571

The Relationship Between Walking Capacity, Biopsychosocial Factors, Self-Efficacy and Walking Activity in Individuals Post Stroke

PubMed Central

Danks, Kelly A.; Pohlig, Ryan T.; Roos, Margie; Wright, Tamara R.; Reisman, Darcy S.

2016-01-01

Background/Purpose Many factors appear to be related to physical activity after stroke, yet it is unclear how these factors interact and which ones might be the best predictors. Therefore, the purpose of this study was twofold: 1) to examine the relationship between walking capacity and walking activity, and 2) to investigate how biopsychosocial factors and self-efficacy relate to walking activity, above and beyond walking capacity impairment post-stroke. Methods Individuals greater than 3 months post-stroke (n=55) completed the Yesavage Geriatric Depression Scale (GDS), Fatigue Severity Scale (FSS), Modified Cumulative Illness Rating (MCIR) Scale, Walk 12, Activities Specific Balance Confidence (ABC) Scale, Functional Gait Assessment (FGA), and oxygen consumption testing. Walking activity data was collected via a StepWatch Activity Monitor (SAM). Predictors were grouped into 3 constructs: (1) Walking Capacity: oxygen consumption and FGA; (2) Biopsychosocial: GDS, FSS, and MCIR; (3) Self-Efficacy: Walk 12 and ABC. Moderated sequential regression models were used to examine what factors best predicted walking activity. Results Walking capacity explained 35.9% (p<0.001) of the variance in walking activity. Self-efficacy (ΔR2 = 0.15, p<0.001) and the interaction between the FGA*ABC (ΔR2 = 0.047, p<0.001) significantly increased the variability explained. FGA (β=0.37, p=0.01), MCIR (β=−0.26, p=0.01), and Walk 12 (β=−0.45, p=0.00) were each individually significantly associated with walking activity. Discussion/Conclusion While measures of walking capacity and self-efficacy significantly contributed to "real-world" walking activity, balance self-efficacy moderated the relationship between walking capacity and walking activity. Improving low balance self-efficacy may augment walking capacity and translate to improved walking activity post-stroke. PMID:27548750

Relationship between oxygen cost of walking and level of walking disability after stroke: An experimental study.

PubMed

Polese, Janaine C; Ada, Louise; Teixeira-Salmela, Luci F

2018-01-01

Since physical inactivity is the major risk factor for recurrent stroke, it is important to understand how level of disability impacts oxygen uptake by people after stroke. This study investigated the nature of the relationship between level of disability and oxygen cost in people with chronic stroke. Level of walking disability was measured as comfortable walking speed using the 10-m Walk Test reported in m/s with 55 ambulatory people 2 years after stroke. Oxygen cost was measured during 3 walking tasks: overground walking at comfortable speed, overground walking at fast speed, and stair walking at comfortable speed. Oxygen cost was calculated from oxygen uptake divided by distance covered during walking and reported in ml∙kg -1 ∙m -1 . The relationship between level of walking disability and oxygen cost was curvilinear for all 3 walking tasks. One quadratic model accounted for 81% (95% CI [74, 88]) of the variance in oxygen cost during the 3 walking tasks: [Formula: see text] DISCUSSION: The oxygen cost of walking was related the level of walking disability in people with chronic stroke, such that the more disabled the individual, the higher the oxygen cost of walking; with oxygen cost rising sharply as disability became severe. An equation that relates oxygen cost during different walking tasks according to the level of walking disability allows clinicians to determine oxygen cost indirectly without the difficulty of measuring oxygen uptake directly. Copyright © 2017 John Wiley & Sons, Ltd.

A novel pixellated solid-state photon detector for enhancing the Everhart-Thornley detector.

PubMed

Chuah, Joon Huang; Holburn, David

2013-06-01

This article presents a pixellated solid-state photon detector designed specifically to improve certain aspects of the existing Everhart-Thornley detector. The photon detector was constructed and fabricated in an Austriamicrosystems 0.35 µm complementary metal-oxide-semiconductor process technology. This integrated circuit consists of an array of high-responsivity photodiodes coupled to corresponding low-noise transimpedance amplifiers, a selector-combiner circuit and a variable-gain postamplifier. Simulated and experimental results show that the photon detector can achieve a maximum transimpedance gain of 170 dBΩ and minimum bandwidth of 3.6 MHz. It is able to detect signals with optical power as low as 10 nW and produces a minimum signal-to-noise ratio (SNR) of 24 dB regardless of gain configuration. The detector has been proven to be able to effectively select and combine signals from different pixels. The key advantages of this detector are smaller dimensions, higher cost effectiveness, lower voltage and power requirements and better integration. The photon detector supports pixel-selection configurability which may improve overall SNR and also potentially generate images for different analyses. This work has contributed to the future research of system-level integration of a pixellated solid-state detector for secondary electron detection in the scanning electron microscope. Copyright © 2013 Wiley Periodicals, Inc.

Studies on a 300 k pixel detector telescope

NASA Astrophysics Data System (ADS)

Middelkamp, Peter; Antinori, F.; Barberis, D.; Becks, K. H.; Beker, H.; Beusch, W.; Burger, P.; Campbell, M.; Cantatore, E.; Catanesi, M. G.; Chesi, E.; Darbo, G.; D'Auria, S.; Davia, C.; di Bari, D.; di Liberto, S.; Elia, D.; Gys, T.; Heijne, E. H. M.; Helstrup, H.; Jacholkowski, A.; Jæger, J. J.; Jakubek, J.; Jarron, P.; Klempt, W.; Krummenacher, F.; Knudson, K.; Kralik, I.; Kubasta, J.; Lasalle, J. C.; Leitner, R.; Lemeilleur, F.; Lenti, V.; Letheren, M.; Lopez, L.; Loukas, D.; Luptak, M.; Martinengo, P.; Meddeler, G.; Meddi, F.; Morando, M.; Munns, A.; Pellegrini, F.; Pengg, F.; Pospisil, S.; Quercigh, E.; Ridky, J.; Rossi, L.; Safarik, K.; Scharfetter, L.; Segato, G.; Simone, S.; Smith, K.; Snoeys, W.; Vrba, V.

1996-02-01

Four silicon pixel detector planes are combined to form a tracking telescope in the lead ion experiment WA97 at CERN with 290 304 sensitive elements each of 75 μm by 500 μm area. An electronic pulse processing circuit is associated with each individual sensing element and the response for ionizing particles is binary with an adjustable threshold. The noise rate for a threshold of 6000 e- has been measured to be less than 10-10. The inefficient area due to malfunctioning pixels is 2.8% of the 120 cm2. Detector overlaps within one plane have been used to determine the alignment of the components of the plane itself, without need for track reconstruction using external detectors. It is the first time that such a big surface covered with active pixels has been used in a physics experiment. Some aspects concerning inclined particle tracks and time walk have been measured separately in a beam test at the CERN SPS H6 beam.

Walking economy during cued versus non-cued treadmill walking in persons with Parkinson's disease.

PubMed

Gallo, Paul M; McIsaac, Tara L; Garber, Carol Ewing

2013-01-01

Gait impairment is common in Parkinson's disease (PD) and may result in greater energy expenditure, poorer walking economy, and fatigue during activities of daily living. Auditory cueing is an effective technique to improve gait; but the effects on energy expenditure are unknown. To determine whether energy expenditure differs in individuals with PD compared with healthy controls and if auditory cueing improves walking economy in PD. Twenty participants (10 PD and 10 controls) came to the laboratory for three sessions. Participants performed two, 6-minute bouts of treadmill walking at two speeds (1.12 m·sec-1 and 0.67 m·sec-1). One session used cueing and the other without cueing. A metabolic cart measured energy expenditure and walking economy was calculated (energy expenditure/power). PD had worse walking economy and higher energy expenditure than control participants during cued and non-cued walking at the 0.67 m·sec-1 speed and during non-cued walking at the 1.12 m·sec-1. With auditory cueing, energy expenditure and walking economy worsened in both participant groups. People with PD use more energy and have worse walking economy than adults without PD. Walking economy declines further with auditory cuing in persons with PD.

Walk This Way

ERIC Educational Resources Information Center

Mason, Nick

2007-01-01

A generation ago, it was part of growing up for all kids when they biked or walked to school. But in the last 30 years, heavier traffic, wider roads and more dangerous intersections have made it riskier for students walking or pedaling. Today, fewer than 15 percent of kids bike or walk to school compared with more than 50 percent in 1969. In the…

Ultrafast, superhigh gain visible-blind UV detector and optical logic gates based on nonpolar a-axial GaN nanowire

NASA Astrophysics Data System (ADS)

Wang, Xingfu; Zhang, Yong; Chen, Xinman; He, Miao; Liu, Chao; Yin, Yian; Zou, Xianshao; Li, Shuti

2014-09-01

Nonpolar a-axial GaN nanowire (NW) was first used to construct the MSM (metal-semiconductor-metal) symmetrical Schottky contact device for application as visible-blind ultraviolet (UV) detector. Without any surface or composition modifications, the fabricated device demonstrated a superior performance through a combination of its high sensitivity (up to 104 A W-1) and EQE value (up to 105), as well as ultrafast (<26 ms) response speed, which indicates that a balance between the photocurrent gain and the response speed has been achieved. Based on its excellent photoresponse performance, an optical logic AND gate and OR gate have been demonstrated for performing photo-electronic coupled logic devices by further integrating the fabricated GaN NW detectors, which logically convert optical signals to electrical signals in real time. These results indicate the possibility of using a nonpolar a-axial GaN NW not only as a high performance UV detector, but also as a stable optical logic device, both in light-wave communications and for future memory storage.Nonpolar a-axial GaN nanowire (NW) was first used to construct the MSM (metal-semiconductor-metal) symmetrical Schottky contact device for application as visible-blind ultraviolet (UV) detector. Without any surface or composition modifications, the fabricated device demonstrated a superior performance through a combination of its high sensitivity (up to 104 A W-1) and EQE value (up to 105), as well as ultrafast (<26 ms) response speed, which indicates that a balance between the photocurrent gain and the response speed has been achieved. Based on its excellent photoresponse performance, an optical logic AND gate and OR gate have been demonstrated for performing photo-electronic coupled logic devices by further integrating the fabricated GaN NW detectors, which logically convert optical signals to electrical signals in real time. These results indicate the possibility of using a nonpolar a-axial GaN NW not only as a high

Using built environment characteristics to predict walking for exercise

PubMed Central

Lovasi, Gina S; Moudon, Anne V; Pearson, Amber L; Hurvitz, Philip M; Larson, Eric B; Siscovick, David S; Berke, Ethan M; Lumley, Thomas; Psaty, Bruce M

2008-01-01

Background Environments conducive to walking may help people avoid sedentary lifestyles and associated diseases. Recent studies developed walkability models combining several built environment characteristics to optimally predict walking. Developing and testing such models with the same data could lead to overestimating one's ability to predict walking in an independent sample of the population. More accurate estimates of model fit can be obtained by splitting a single study population into training and validation sets (holdout approach) or through developing and evaluating models in different populations. We used these two approaches to test whether built environment characteristics near the home predict walking for exercise. Study participants lived in western Washington State and were adult members of a health maintenance organization. The physical activity data used in this study were collected by telephone interview and were selected for their relevance to cardiovascular disease. In order to limit confounding by prior health conditions, the sample was restricted to participants in good self-reported health and without a documented history of cardiovascular disease. Results For 1,608 participants meeting the inclusion criteria, the mean age was 64 years, 90 percent were white, 37 percent had a college degree, and 62 percent of participants reported that they walked for exercise. Single built environment characteristics, such as residential density or connectivity, did not significantly predict walking for exercise. Regression models using multiple built environment characteristics to predict walking were not successful at predicting walking for exercise in an independent population sample. In the validation set, none of the logistic models had a C-statistic confidence interval excluding the null value of 0.5, and none of the linear models explained more than one percent of the variance in time spent walking for exercise. We did not detect significant

Cellular telephone use during free-living walking significantly reduces average walking speed.

PubMed

Barkley, Jacob E; Lepp, Andrew

2016-03-31

Cellular telephone (cell phone) use decreases walking speed in controlled laboratory experiments and there is an inverse relationship between free-living walking speed and heart failure risk. The purpose of this study was to examine the impact of cell phone use on walking speed in a free-living environment. Subjects (n = 1142) were randomly observed walking on a 50 m University campus walkway. The time it took each subject to walk 50 m was recorded and subjects were coded into categories: cell phone held to the ear (talking, n = 95), holding and looking at the cell phone (texting, n = 118), not visibly using the cell phone (no use, n = 929). Subjects took significantly (p < 0.001) longer traversing the walkway when talking (39.3 s) and texting (37.9 s) versus no use (35.3 s). As was the case with the previous laboratory experiments, cell phone use significantly reduces average speed during free-living walking.

Detector and energy analyzer for energetic-hydrogen in beams and plasmas

DOEpatents

Bastasz, Robert J.; Hughes, Robert C.; Wampler, William R.

1988-01-01

A detector for detecting energetic hydrogen ions and atoms ranging in energy from about 1 eV up to 1 keV in an evacuated environment includes a Schottky diode with a palladium or palladium-alloy gate metal applied to a silicondioxide layer on an n-silicon substrate. An array of the energetic-hydrogen detectors having a range of energy sensitivities form a plasma energy analyzer having a rapid response time and a sensitivity for measuring fluxes of energetic hydrogen. The detector is sensitive to hydrogen and its isotopes but is insensitive to non-hydrogenic particles. The array of energetic-hydrogen detectors can be formed on a single silicon chip, with thin-film layers of gold metal applied in various thicknesses to successive detectors in the array. The gold layers serve as particle energy-filters so that each detector is sensitive to a different range of hydrogen energies.

Detector and energy analyzer for energetic-hydrogen in beams and plasmas

DOEpatents

Bastasz, R.J.; Hughes, R.C.; Wampler, W.R.

1988-11-01

A detector for detecting energetic hydrogen ions and atoms ranging in energy from about 1 eV up to 1 keV in an evacuated environment includes a Schottky diode with a palladium or palladium-alloy gate metal applied to a silicon-dioxide layer on an n-silicon substrate. An array of the energetic-hydrogen detectors having a range of energy sensitivities form a plasma energy analyzer having a rapid response time and a sensitivity for measuring fluxes of energetic hydrogen. The detector is sensitive to hydrogen and its isotopes but is insensitive to non-hydrogenic particles. The array of energetic-hydrogen detectors can be formed on a single silicon chip, with thin-film layers of gold metal applied in various thicknesses to successive detectors in the array. The gold layers serve as particle energy-filters so that each detector is sensitive to a different range of hydrogen energies. 4 figs.

Record statistics of financial time series and geometric random walks

NASA Astrophysics Data System (ADS)

Sabir, Behlool; Santhanam, M. S.

2014-09-01

The study of record statistics of correlated series in physics, such as random walks, is gaining momentum, and several analytical results have been obtained in the past few years. In this work, we study the record statistics of correlated empirical data for which random walk models have relevance. We obtain results for the records statistics of select stock market data and the geometric random walk, primarily through simulations. We show that the distribution of the age of records is a power law with the exponent α lying in the range 1.5≤α≤1.8. Further, the longest record ages follow the Fréchet distribution of extreme value theory. The records statistics of geometric random walk series is in good agreement with that obtained from empirical stock data.

Angular-momentum-dependent splitting of light through metal nanohole

NASA Astrophysics Data System (ADS)

Hu, Dejiao; Liu, Yu; Zhang, ZhiYou; Xiao, Xiao; Du, JingLei

2014-11-01

We numerically study the splitting of light beam which carries orbital angular momentum (OAM) through single metal nano-scale hole. A light beam carrying with OAM has a helical phase distribution in the transverse plane, where the electric field has the form: E(r,θ)=E0exp(lθ), and l is the topological charge which denotes the value of OAM. The circular polarization state is corresponding to the spin angular momentum (SAM), where s=+1 represents the left-handed polarization and s=-1 the right-handed polarization. Simulation results show l dependent splitting of beam through nano metal hole. When l is odd, the transmitted far field splits while no splitting happens when l is even. This phenomenon is attributed to the interaction between OAM beam and plasmonic mode of metal nano-hole. It is revealed that different OAM beam can excite different transverse mode in the metal cavity, which means the interaction should obey an OAM section rule. We show that even l can excite transverse mode with zero total AM and odd l can excite transverse mode with non-zero total AM within the hole. Orbital-spin conversion is also revealed in the free wave/plasmon interaction.

Talk the Walk: Does Socio-Cognitive Resource Reallocation Facilitate the Development of Walking?

PubMed

Geva, Ronny; Orr, Edna

2016-01-01

Walking is of interest to psychology, robotics, zoology, neuroscience and medicine. Human's ability to walk on two feet is considered to be one of the defining characteristics of hominoid evolution. Evolutionary science propses that it emerged in response to limited environmental resources; yet the processes supporting its emergence are not fully understood. Developmental psychology research suggests that walking elicits cognitive advancements. We postulate that the relationship between cognitive development and walking is a bi-directional one; and further suggest that the initiation of novel capacities, such as walking, is related to internal socio-cognitive resource reallocation. We shed light on these notions by exploring infants' cognitive and socio-communicative outputs prospectively from 6-18 months of age. Structured bi/tri weekly evaluations of symbolic and verbal development were employed in an urban cohort (N = 9) for 12 months, during the transition from crawling to walking. Results show links between preemptive cognitive changes in socio-communicative output, symbolic-cognitive tool-use processes, and the age of emergence of walking. Plots of use rates of lower symbolic play levels before and after emergence of new skills illustrate reductions in use of previously attained key behaviors prior to emergence of higher symbolic play, language and walking. Further, individual differences in age of walking initiation were strongly related to the degree of reductions in complexity of object-use (r = .832, p < .005), along with increases, counter to the general reduction trend, in skills that serve recruitment of external resources [socio-communication bids before speech (r = -.696, p < .01), and speech bids before walking; r = .729, p < .01)]. Integration of these proactive changes using a computational approach yielded an even stronger link, underscoring internal resource reallocation as a facilitator of walking initiation (r = .901, p<0.001). These

Talk the Walk: Does Socio-Cognitive Resource Reallocation Facilitate the Development of Walking?

PubMed Central

Orr, Edna

2016-01-01

Walking is of interest to psychology, robotics, zoology, neuroscience and medicine. Human’s ability to walk on two feet is considered to be one of the defining characteristics of hominoid evolution. Evolutionary science propses that it emerged in response to limited environmental resources; yet the processes supporting its emergence are not fully understood. Developmental psychology research suggests that walking elicits cognitive advancements. We postulate that the relationship between cognitive development and walking is a bi-directional one; and further suggest that the initiation of novel capacities, such as walking, is related to internal socio-cognitive resource reallocation. We shed light on these notions by exploring infants’ cognitive and socio-communicative outputs prospectively from 6–18 months of age. Structured bi/tri weekly evaluations of symbolic and verbal development were employed in an urban cohort (N = 9) for 12 months, during the transition from crawling to walking. Results show links between preemptive cognitive changes in socio-communicative output, symbolic-cognitive tool-use processes, and the age of emergence of walking. Plots of use rates of lower symbolic play levels before and after emergence of new skills illustrate reductions in use of previously attained key behaviors prior to emergence of higher symbolic play, language and walking. Further, individual differences in age of walking initiation were strongly related to the degree of reductions in complexity of object-use (r = .832, p < .005), along with increases, counter to the general reduction trend, in skills that serve recruitment of external resources [socio-communication bids before speech (r = -.696, p < .01), and speech bids before walking; r = .729, p < .01)]. Integration of these proactive changes using a computational approach yielded an even stronger link, underscoring internal resource reallocation as a facilitator of walking initiation (r = .901, p<0.001). These

Reducing Circumduction and Hip Hiking During Hemiparetic Walking Through Targeted Assistance of the Paretic Limb Using a Soft Robotic Exosuit.

PubMed

Awad, Louis N; Bae, Jaehyun; Kudzia, Pawel; Long, Andrew; Hendron, Kathryn; Holt, Kenneth G; OʼDonnell, Kathleen; Ellis, Terry D; Walsh, Conor J

2017-10-01

The aim of the study was to evaluate the effects on common poststroke gait compensations of a soft wearable robot (exosuit) designed to assist the paretic limb during hemiparetic walking. A single-session study of eight individuals in the chronic phase of stroke recovery was conducted. Two testing conditions were compared: walking with the exosuit powered versus walking with the exosuit unpowered. Each condition was 8 minutes in duration. Compared with walking with the exosuit unpowered, walking with the exosuit powered resulted in reductions in hip hiking (27 [6%], P = 0.004) and circumduction (20 [5%], P = 0.004). A relationship between changes in knee flexion and changes in hip hiking was observed (Pearson r = -0.913, P < 0.001). Similarly, multivariate regression revealed that changes in knee flexion (β = -0.912, P = 0.007), but not ankle dorsiflexion (β = -0.194, P = 0.341), independently predicted changes in hip hiking (R = 0.87, F(2, 4) = 13.48, P = 0.017). Exosuit assistance of the paretic limb during walking produces immediate changes in the kinematic strategy used to advance the paretic limb. Future work is necessary to determine how exosuit-induced reductions in paretic hip hiking and circumduction during gait training could be leveraged to facilitate more normal walking behavior during unassisted walking.

Stabilization of a three-dimensional limit cycle walking model through step-to-step ankle control.

PubMed

Kim, Myunghee; Collins, Steven H

2013-06-01

Unilateral, below-knee amputation is associated with an increased risk of falls, which may be partially related to a loss of active ankle control. If ankle control can contribute significantly to maintaining balance, even in the presence of active foot placement, this might provide an opportunity to improve balance using robotic ankle-foot prostheses. We investigated ankle- and hip-based walking stabilization methods in a three-dimensional model of human gait that included ankle plantarflexion, ankle inversion-eversion, hip flexion-extension, and hip ad/abduction. We generated discrete feedback control laws (linear quadratic regulators) that altered nominal actuation parameters once per step. We used ankle push-off, lateral ankle stiffness and damping, fore-aft foot placement, lateral foot placement, or all of these as control inputs. We modeled environmental disturbances as random, bounded, unexpected changes in floor height, and defined balance performance as the maximum allowable disturbance value for which the model walked 500 steps without falling. Nominal walking motions were unstable, but were stabilized by all of the step-to-step control laws we tested. Surprisingly, step-by-step modulation of ankle push-off alone led to better balance performance (3.2% leg length) than lateral foot placement (1.2% leg length) for these control laws. These results suggest that appropriate control of robotic ankle-foot prosthesis push-off could make balancing during walking easier for individuals with amputation.

The effects of narrow and elevated path walking on aperture crossing.

PubMed

Hackney, Amy L; Cinelli, Michael E; Denomme, Luke T; Frank, James S

2015-06-01

The study investigated the impact that action capabilities have on identifying possibilities for action, particularly how postural threat influences the passability of apertures. To do this, the ability to maintain balance was challenged by manipulating the level of postural threat while walking. First, participants walked along a 7m path and passed through two vertical obstacles spaced 1.1-1.5×the shoulder width apart during normal walking. Next, postural threat was manipulated by having participants complete the task either walking on a narrow, ground level path or on an elevated/narrow path. Despite a decrease in walking speed as well as an increase in trunk sway in both the narrow and elevated/narrow walking conditions, the passability of apertures was only affected when the consequence of instability was greatest. In the elevated/narrow walking condition, individuals maintained a larger critical point (rotated their shoulders for larger aperture widths) compared to normal walking. However, this effect was not observed for the narrow path walking suggesting that the level of postural threat was not enough to impose similar changes to the critical point. Therefore, it appears that manipulating action capabilities by increasing postural threat does indeed influence aperture crossing behavior, however the consequence associated with instability must be high before both gait characteristics and the critical point are affected. Copyright © 2015 Elsevier B.V. All rights reserved.

Walking football as sustainable exercise for older adults - A pilot investigation.

PubMed

Reddy, Peter; Dias, Irundika; Holland, Carol; Campbell, Niyah; Nagar, Iaysha; Connolly, Luke; Krustrup, Peter; Hubball, Harry

2017-06-01

The health benefits of playing football and the importance of exercise and social contact for healthy ageing are well established, but few older adults in the UK take enough exercise. Football is popular, flexible in format and draws players into engrossing, effortful and social exercise, but the physical demands of play at full speed may make it unsustainable for some older adults. Restricted to walking pace, will play still be engaging? Will health benefits be retained? Will physical demands remain manageable? This pilot study aims to investigate: (1) the experience of older adults playing walking football every week, is it sustainable and rewarding, (2) the intensity and locomotor pattern of walking football, (3) the scale and nature of walking football health benefits and (4) possible cognitive benefits of playing walking football through measures of processing speed, selective and divided attention and updating and inhibition components of executive function.
 'Walking football' and 'waiting list' groups were compared before and after 12 weeks of one-hour per week football. Walking football was found to be engaging, sustainable for older adults and moderately intensive; however, selective health and cognitive benefits were not found from this brief intervention. Highlights Walking football is a lower impact but authentic form of football that enables older players to extend their active participation. Walking football is enjoyable and moderately demanding and may be a sustainable form of exercise for older adults. Health and cognitive benefits to playing walking football were not found.

The effect of objectively measured crime on walking in minority adults.

PubMed

McDonald, Noreen C

2008-01-01

Evaluate the relationship between neighborhood crime and the amount of daily walking by minority adults. This was a cross-sectional study of minority adult walking behavior and crime. Setting. Oakland, California was chosen as the study area because of the substantial spatial variation in levels of criminal activity combined with detailed information on walking trips. The study was restricted to minority adults who responded to the 2000 Bay Area Travel Survey and lived in Oakland, California (n = 359). Data on leisure and utilitarian walking were collected through the 2000 Bay Area Travel Survey and combined with crime data from the Oakland Police Department. A negative binomial model was used to test if violent, property, or quality of life crimes had significant associations with daily minutes walked, controlling for individual and neighborhood covariates. The model showed a significant negative association between violent crime and minutes walked per day (b = -.07; p = .016). Neither property nor quality of life crimes were correlated with amount of walking. Reductions in violent crime may increase opportunities for minority residents in urban areas to participate in physical activity such as walking, thereby providing another reason to pursue anticrime measures. Urban designers' efforts to increase physical activity by improving neighborhood walkability may consider violent crime prevention in their designs.

Origins of ultralow velocity zones through slab-derived metallic melt

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

Liu, Jiachao; Li, Jie; Hrubiak, Rostislav

2016-05-03

Understanding the ultralow velocity zones (ULVZs) places constraints on the chemical composition and thermal structure of deep Earth and provides critical information on the dynamics of large-scale mantle convection, but their origin has remained enigmatic for decades. Recent studies suggest that metallic iron and carbon are produced in subducted slabs when they sink beyond a depth of 250 km. Here we show that the eutectic melting curve of the iron-carbon system crosses the current geotherm near Earth’s core-mantle boundary, suggesting that dense metallic melt may form in the lowermost mantle. If concentrated into isolated patches, such melt could produce themore » seismically observed density and velocity features of ULVZs. Depending on the wetting behavior of the metallic melt, the resultant ULVZs may be short-lived domains that are replenished or regenerated through subduction, or long-lasting regions containing both metallic and silicate melts. Slab-derived metallic melt may produce another type of ULVZ that escapes core sequestration by reacting with the mantle to form iron-rich post-bridgmanite or ferropericlase. The hypotheses connect peculiar features near Earth’s core-mantle boundary to subduction of the oceanic lithosphere through the deep carbon cycle.« less

Design and optimization of a novel 3D detector: The 3D-open-shell-electrode detector

NASA Astrophysics Data System (ADS)

Liu, Manwen; Tan, Jian; Li, Zheng

2018-04-01

A new type of three-dimensional (3D) detector, namely 3D-Open-Shell-Electrode Detector (3DOSED), is proposed in this study. In a 3DOSED, the trench electrode can be etched all the way through the detector thickness, totally eliminating the low electric field region existed in the conventional 3D-Trench-Electrode detector. Full 3D technology computer-aided design (TCAD) simulations have been done on this novel silicon detector structure. Through comparing of the simulation results of the detector, we can obtain the best design of the 3SOSED. In addition, simulation results show that, as compared to the conventional 3D detector, the proposed 3DOSED can improve not only detector charge collection efficiency but also its radiation hardness with regard to solving the trapping problem in the detector bulk. What is more, it has been shown that detector full depletion voltage is also slightly reduced, which can improve the utility aspects of the detector. When compared to the conventional 3D detector, we find that the proposed novel 3DOSED structure has better electric potential and electric field distributions, and better electrical properties such as detector full depletion voltage. In 3DOSED array, each pixel cell is isolated from each other by highly doped trenches, but also electrically and physically connected with each other through the remaining silicon bulk between broken electrodes.

A marching-walking hybrid induces step length adaptation and transfers to natural walking.

PubMed

Long, Andrew W; Finley, James M; Bastian, Amy J

2015-06-01

Walking is highly adaptable to new demands and environments. We have previously studied adaptation of locomotor patterns via a split-belt treadmill, where subjects learn to walk with one foot moving faster than the other. Subjects learn to adapt their walking pattern by changing the location (spatial) and time (temporal) of foot placement. Here we asked whether we can induce adaptation of a specific walking pattern when one limb does not "walk" but instead marches in place (i.e., marching-walking hybrid). The marching leg's movement is limited during the stance phase, and thus certain sensory signals important for walking may be reduced. We hypothesized that this would produce a spatial-temporal strategy different from that of normal split-belt adaptation. Healthy subjects performed two experiments to determine whether they could adapt their spatial-temporal pattern of step lengths during the marching-walking hybrid and whether the learning transfers to over ground walking. Results showed that the hybrid group did adapt their step lengths, but the time course of adaptation and deadaption was slower than that for the split-belt group. We also observed that the hybrid group utilized a mostly spatial strategy whereas the split-belt group utilized both spatial and temporal strategies. Surprisingly, we found no significant difference between the hybrid and split-belt groups in over ground transfer. Moreover, the hybrid group retained more of the learned pattern when they returned to the treadmill. These findings suggest that physical rehabilitation with this marching-walking paradigm on conventional treadmills may produce changes in symmetry comparable to what is observed during split-belt training. Copyright © 2015 the American Physiological Society.

Quantifying metal artefact reduction using virtual monochromatic dual-layer detector spectral CT imaging in unilateral and bilateral total hip prostheses.

PubMed

Wellenberg, R H H; Boomsma, M F; van Osch, J A C; Vlassenbroek, A; Milles, J; Edens, M A; Streekstra, G J; Slump, C H; Maas, M

2017-03-01

To quantify the impact of prosthesis material and design on the reduction of metal artefacts in total hip arthroplasties using virtual monochromatic dual-layer detector Spectral CT imaging. The water-filled total hip arthroplasty phantom was scanned on a novel 128-slice Philips IQon dual-layer detector Spectral CT scanner at 120-kVp and 140-kVp at a standard computed tomography dose index of 20.0mGy. Several unilateral and bilateral hip prostheses consisting of different metal alloys were inserted and combined which were surrounded by 18 hydroxyapatite calcium carbonate pellets representing bone. Images were reconstructed with iterative reconstruction and analysed at monochromatic energies ranging from 40 to 200keV. CT numbers in Hounsfield Units (HU), noise measured as the standard deviation in HU, signal-to-noise-ratios (SNRs) and contrast-to-noise-ratios (CNRs) were analysed within fixed regions-of-interests placed in and around the pellets. In 70 and 74keV virtual monochromatic images the CT numbers of the pellets were similar to 120-kVp and 140-kVp polychromatic results, therefore serving as reference. A separation into three categories of metal artefacts was made (no, mild/moderate and severe) where pellets were categorized based on HU deviations. At high keV values overall image contrast was reduced. For mild/moderate artefacts, the highest average CNRs were attained with virtual monochromatic 130keV images, acquired at 140-kVp. Severe metal artefacts were not reduced. In 130keV images, only mild/moderate metal artefacts were significantly reduced compared to 70 and 74keV images. Deviations in CT numbers, noise, SNRs and CNRs due to metal artefacts were decreased with respectively 64%, 57%, 62% and 63% (p<0.001) compared to unaffected pellets. Optimal keVs, based on CNRs, for different unilateral and bilateral metal hip prostheses consisting of different metal alloys varied from 74 to 150keV. The Titanium alloy resulted in less severe artefacts and were

Development of Ultra-Low Noise, High Sensitivity Planar Metal Grating Coupled AlGaAs/GaAs Multiquantum Well IR Detectors for Focal Plane Array Staring IR Sensor Systems

DTIC Science & Technology

1992-05-01

Development of Ultra-Low Noise , High Sensitivity Planar Metal Grating Coupled AlGaAs/GaAs Multiquantum Well IR Detectors for Focal Plane Array...February 1 - April 30, 1992 Project Title: Development of low- noise high-detectivity planar metal grating coupled III-V multiquantum-well/superlattice...low- noise and high-detectivity planar metal grating coupled bound-to- miniband (BTM) GaAs/AlGaAs and step-bound-to-miniband (SBTM) InGaAs/AlGaAs /GaAs

First Person Perspective of Seated Participants Over a Walking Virtual Body Leads to Illusory Agency Over the Walking.

PubMed

Kokkinara, Elena; Kilteni, Konstantina; Blom, Kristopher J; Slater, Mel

2016-07-01

Agency, the attribution of authorship to an action of our body, requires the intention to carry out the action, and subsequently a match between its predicted and actual sensory consequences. However, illusory agency can be generated through priming of the action together with perception of bodily action, even when there has been no actual corresponding action. Here we show that participants can have the illusion of agency over the walking of a virtual body even though in reality they are seated and only allowed head movements. The experiment (n = 28) had two factors: Perspective (1PP or 3PP) and Head Sway (Sway or NoSway). Participants in 1PP saw a life-sized virtual body spatially coincident with their own from a first person perspective, or the virtual body from third person perspective (3PP). In the Sway condition the viewpoint included a walking animation, but not in NoSway. The results show strong illusions of body ownership, agency and walking, in the 1PP compared to the 3PP condition, and an enhanced level of arousal while the walking was up a virtual hill. Sway reduced the level of agency. We conclude with a discussion of the results in the light of current theories of agency.

Novel ZnO:Al contacts to CdZnTe for X- and gamma-ray detectors

PubMed Central

Roy, U. N.; Mundle, R. M.; Camarda, G. S.; Cui, Y.; Gul, R.; Hossain, A.; Yang, G.; Pradhan, A. K.; James, R. B.

2016-01-01

CdZnTe (CZT) has made a significant impact as a material for room-temperature nuclear-radiation detectors due to its potential impact in applications related to nonproliferation, homeland security, medical imaging, and gamma-ray telescopes. In all such applications, common metals, such as gold, platinum and indium, have been used as electrodes for fabricating the detectors. Because of the large mismatch in the thermal-expansion coefficient between the metal contacts and CZT, the contacts can undergo stress and mechanical degradation, which is the main cause for device instability over the long term. Here, we report for the first time on our use of Al-doped ZnO as the preferred electrode for such detectors. The material was selected because of its better contact properties compared to those of the metals commonly used today. Comparisons were conducted for the detector properties using different contacts, and improvements in the performances of ZnO:Al-coated detectors are described in this paper. These studies show that Al:ZnO contacts to CZT radiation detectors offer the potential of becoming a transformative replacement for the common metallic contacts due to the dramatic improvements in the performance of detectors and improved long-term stability. PMID:27216387

Detonation Propagation through Nitromethane Embedded Metal Foam

NASA Astrophysics Data System (ADS)

Lieberthal, Brandon; Maines, Warren R.; Stewart, D. Scott

2015-11-01

There is considerable interest in developing a better understanding of dynamic behaviors of multicomponent systems. We report results of Eulerian hydrodynamic simulations of shock waves propagating through metal foam at approximately 20% relative density and various porosities using a reactive flow model in the ALE3D software package. We investigate the applied pressure and energy of the shock wave and its effects on the fluid and the inert material interface. By varying pore sizes, as well as metal impedance, we predict the overall effects of heterogeneous material systems at the mesoscale. In addition, we observe a radially expanding blast front in these heterogeneous models and apply the theory of Detonation Shock Dynamics to the convergence behavior of the lead shock.

Dopant-controlled single-electron pumping through a metallic island

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

Wenz, Tobias, E-mail: tobias.wenz@ptb.de; Hohls, Frank, E-mail: frank.hohls@ptb.de; Jehl, Xavier

We investigate a hybrid metallic island/single dopant electron pump based on fully depleted silicon-on-insulator technology. Electron transfer between the central metallic island and the leads is controlled by resonant tunneling through single phosphorus dopants in the barriers. Top gates above the barriers are used to control the resonance conditions. Applying radio frequency signals to the gates, non-adiabatic quantized electron pumping is achieved. A simple deterministic model is presented and confirmed by comparing measurements with simulations.

Physics and Applications of Metallic Magnetic Calorimeters

NASA Astrophysics Data System (ADS)

Kempf, S.; Fleischmann, A.; Gastaldo, L.; Enss, C.

2018-03-01

Metallic magnetic calorimeters (MMCs) are calorimetric low-temperature particle detectors that are currently strongly advancing the state of the art in energy-dispersive single particle detection. They are typically operated at temperatures below 100 mK and make use of a metallic, paramagnetic temperature sensor to transduce the temperature rise of the detector upon the absorption of an energetic particle into a change of magnetic flux which is sensed by a superconducting quantum interference device. This outstanding interplay between a high-sensitivity thermometer and a near quantum-limited amplifier results in a very fast signal rise time, an excellent energy resolution, a large dynamic range, a quantum efficiency close to 100% as well as an almost ideal linear detector response. For this reason, a growing number of groups located all over the world is developing MMC arrays of various sizes which are routinely used in a variety of applications. Within this paper, we briefly review the state of the art of metallic magnetic calorimeters. This includes a discussion of the detection principle, sensor materials and detector geometries, readout concepts, the structure of modern detectors as well as the state-of-the-art detector performance.

"I'm Just a'-Walking the Dog" correlates of regular dog walking.

PubMed

Christian nee Cutt, Hayley; Giles-Corti, Billie; Knuiman, Matthew

2010-01-01

Intrapersonal and environmental factors associated with dog walking (N = 483) were examined. A greater proportion of regular (80%) than irregular (59%) dog walkers met the recommended 150 minutes of physical activity per week. Owners who perceived greater social support and motivation from their dogs to walk, and who had access to a dog-supportive park within their neighborhood, were more likely to regularly walk with their dogs, even after adjustment for other well-known correlates of physical activity. The higher level of physical activity of regular dog walkers can be attributed to the additional walking these owners perform with their dogs.

The Relationship Between Objectively Measured Walking and Risk of Pedestrian-Motor Vehicle Collision.

PubMed

Quistberg, D Alex; Howard, Eric J; Hurvitz, Philip M; Moudon, Anne V; Ebel, Beth E; Rivara, Frederick P; Saelens, Brian E

2017-05-01

Safe urban walking environments may improve health by encouraging physical activity, but the relationship between an individual's location and walking pattern and the risk of pedestrian-motor vehicle collision is unknown. We examined associations between individuals' walking bouts and walking risk, measured as mean exposure to the risk of pedestrian-vehicle collision. Walking bouts were ascertained through integrated accelerometry and global positioning system data and from individual travel-diary data obtained from adults in the Travel Assessment and Community Study (King County, Washington) in 2008-2009. Walking patterns were superimposed onto maps of the historical probabilities of pedestrian-vehicle collisions for intersections and midblock segments within Seattle, Washington. Mean risk of pedestrian-vehicle collision in specific walking locations was assessed according to walking exposure (duration, distance, and intensity) and participant demographic characteristics in linear mixed models. Participants typically walked in areas with low pedestrian collision risk when walking for recreation, walking at a faster pace, or taking longer-duration walks. Mean daily walking duration and distance were not associated with collision risk. Males walked in areas with higher collision risk compared with females, while vehicle owners, residents of single-family homes, and parents of young children walked in areas with lower collision risk. These findings may suggest that pedestrians moderate collision risk by using lower-risk routes. © The Author 2017. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Tempo and walking speed with music in the urban context

PubMed Central

Franěk, Marek; van Noorden, Leon; Režný, Lukáš

2014-01-01

The study explored the effect of music on the temporal aspects of walking behavior in a real outdoor urban setting. First, spontaneous synchronization between the beat of the music and step tempo was explored. The effect of motivational and non-motivational music (Karageorghis et al., 1999) on the walking speed was also studied. Finally, we investigated whether music can mask the effects of visual aspects of the walking route environment, which involve fluctuation of walking speed as a response to particular environmental settings. In two experiments, we asked participants to walk around an urban route that was 1.8 km in length through various environments in the downtown area of Hradec Králové. In Experiment 1, the participants listened to a musical track consisting of world pop music with a clear beat. In Experiment 2, participants were walking either with motivational music, which had a fast tempo and a strong rhythm, or with non-motivational music, which was slower, nice music, but with no strong implication to movement. Musical beat, as well as the sonic character of the music listened to while walking, influenced walking speed but did not lead to precise synchronization. It was found that many subjects did not spontaneously synchronize with the beat of the music at all, and some subjects synchronized only part of the time. The fast, energetic music increases the speed of the walking tempo, while slower, relaxing music makes the walking tempo slower. Further, it was found that listening to music with headphones while walking can mask the influence of the surrounding environment to some extent. Both motivational music and non-motivational music had a larger effect than the world pop music from Experiment 1. Individual differences in responses to the music listened to while walking that were linked to extraversion and neuroticism were also observed. The findings described here could be useful in rhythmic stimulation for enhancing or recovering the features of

Bicycling and Walking are Associated with Different Cortical Oscillatory Dynamics

PubMed Central

Storzer, Lena; Butz, Markus; Hirschmann, Jan; Abbasi, Omid; Gratkowski, Maciej; Saupe, Dietmar; Schnitzler, Alfons; Dalal, Sarang S.

2016-01-01

Although bicycling and walking involve similar complex coordinated movements, surprisingly Parkinson’s patients with freezing of gait typically remain able to bicycle despite severe difficulties in walking. This observation suggests functional differences in the motor networks subserving bicycling and walking. However, a direct comparison of brain activity related to bicycling and walking has never been performed, neither in healthy participants nor in patients. Such a comparison could potentially help elucidating the cortical involvement in motor control and the mechanisms through which bicycling ability may be preserved in patients with freezing of gait. The aim of this study was to contrast the cortical oscillatory dynamics involved in bicycling and walking in healthy participants. To this end, EEG and EMG data of 14 healthy participants were analyzed, who cycled on a stationary bicycle at a slow cadence of 40 revolutions per minute (rpm) and walked at 40 strides per minute (spm), respectively. Relative to walking, bicycling was associated with a stronger power decrease in the high beta band (23–35 Hz) during movement initiation and execution, followed by a stronger beta power increase after movement termination. Walking, on the other hand, was characterized by a stronger and persisting alpha power (8–12 Hz) decrease. Both bicycling and walking exhibited movement cycle-dependent power modulation in the 24–40 Hz range that was correlated with EMG activity. This modulation was significantly stronger in walking. The present findings reveal differential cortical oscillatory dynamics in motor control for two types of complex coordinated motor behavior, i.e., bicycling and walking. Bicycling was associated with a stronger sustained cortical activation as indicated by the stronger high beta power decrease during movement execution and less cortical motor control within the movement cycle. We speculate this to be due to the more continuous nature of bicycling

Beam walking can detect differences in walking balance proficiency across a range of sensorimotor abilities.

PubMed

Sawers, Andrew; Ting, Lena H

2015-02-01

The ability to quantify differences in walking balance proficiency is critical to curbing the rising health and financial costs of falls. Current laboratory-based approaches typically focus on successful recovery of balance while clinical instruments often pose little difficulty for all but the most impaired patients. Rarely do they test motor behaviors of sufficient difficulty to evoke failures in balance control limiting their ability to quantify balance proficiency. Our objective was to test whether a simple beam-walking task could quantify differences in walking balance proficiency across a range of sensorimotor abilities. Ten experts, ten novices, and five individuals with transtibial limb loss performed six walking trials across three different width beams. Walking balance proficiency was quantified as the ratio of distance walked to total possible distance. Balance proficiency was not significantly different between cohorts on the wide-beam, but clear differences between cohorts on the mid and narrow-beams were identified. Experts walked a greater distance than novices on the mid-beam (average of 3.63±0.04m verus 2.70±0.21m out of 3.66m; p=0.009), and novices walked further than amputees (1.52±0.20m; p=0.03). Amputees were unable to walk on the narrow-beam, while experts walked further (3.07±0.14m) than novices (1.55±0.26m; p=0.0005). A simple beam-walking task and an easily collected measure of distance traveled detected differences in walking balance proficiency across sensorimotor abilities. This approach provides a means to safely study and evaluate successes and failures in walking balance in the clinic or lab. It may prove useful in identifying mechanisms underlying falls versus fall recoveries. Copyright © 2015 Elsevier B.V. All rights reserved.

Optical ionization detector

DOEpatents

Wuest, C.R.; Lowry, M.E.

1994-03-29

An optical ionization detector wherein a beam of light is split so that one arm passes through a fiber optics and the other arm passes through a gas-filled region, and uses interferometry to detect density changes in a gas when charged particles pass through it. The gas-filled region of the detector is subjected to a high electric field and as a charged particle traverses this gas region electrons are freed from the cathode and accelerated so as to generate an electron avalanche which is collected on the anode. The gas density is effected by the electron avalanche formation and if the index or refraction is proportional to the gas density the index will change accordingly. The detector uses this index change by modulating the one arm of the split light beam passing through the gas, with respect to the other arm that is passed through the fiber optic. Upon recombining of the beams, interference fringe changes as a function of the index change indicates the passage of charged particles through the gaseous medium. 3 figures.

Optical ionization detector

DOEpatents

Wuest, Craig R.; Lowry, Mark E.

1994-01-01

An optical ionization detector wherein a beam of light is split so that one arm passes through a fiber optics and the other arm passes through a gas-filled region, and uses interferometry to detect density changes in a gas when charged particles pass through it. The gas-filled region of the detector is subjected to a high electric field and as a charged particle traverses this gas region electrons are freed from the cathode and accelerated so as to generate an electron avalanche which is collected on the anode. The gas density is effected by the electron avalanche formation and if the index or refraction is proportional to the gas density the index will change accordingly. The detector uses this index change by modulating the one arm of the split light beam passing through the gas, with respect to the other arm that is passed through the fiber optic. Upon recombining of the beams, interference fringe changes as a function of the index change indicates the passage of charged particles through the gaseous medium.

Metal prices in the United States through 2010

USGS Publications Warehouse

,

2013-01-01

This report, which updates and revises the U.S. Geological Survey (USGS) (1999) publication, “Metal Prices in the United States Through 1998,” presents an extended price history for a wide range of metals available in a single document. Such information can be useful for the analysis of mineral commodity issues, as well as for other purposes. The chapter for each mineral commodity includes a graph of annual current and constant dollar prices for 1970 through 2010, where available; a list of significant events that affected prices; a brief discussion of the metal and its history; and one or more tables that list current dollar prices. In some cases, the metal prices presented herein are for some alternative form of an element or, instead of a price, a value, such as the value for an import as appraised by the U.S. Customs Service. Also included are the prices for steel, steel scrap, and iron ore—steel because of its importance to the elements used to alloy with it, and steel scrap and iron ore because of their use in steelmaking. A few minor metals, such as calcium, potassium, sodium, strontium, and thorium, for which price histories were insufficient, were excluded. The annual prices given may be averages for the year, yearend prices, or some other price as appropriate for a particular commodity. Certain trade journals have been the source of much of this price information—American Metal Market, ICIS Chemical Business, Engineering and Mining Journal, Industrial Minerals, Metal Bulletin, Mining Journal, Platts Metals Week, Roskill Information Services Ltd. commodity reports, and Ryan’s Notes. Price information also is available in minerals information publications of the USGS (1880–1925, 1996–present) and the U.S. Bureau of Mines (1926–95), such as Mineral Commodity Summaries, Mineral Facts and Problems, Mineral Industry Surveys, and Minerals Yearbook. In addition to prices themselves, these journals and publications contain information relevant to

Finding paths in tree graphs with a quantum walk

NASA Astrophysics Data System (ADS)

Koch, Daniel; Hillery, Mark

2018-01-01

We analyze the potential for different types of searches using the formalism of scattering random walks on quantum computers. Given a particular type of graph consisting of nodes and connections, a "tree maze," we would like to find a selected final node as quickly as possible, faster than any classical search algorithm. We show that this can be done using a quantum random walk, both through numerical calculations as well as by using the eigenvectors and eigenvalues of the quantum system.

Daily intake of trace metals through coffee consumption in India.

PubMed

Suseela, B; Bhalke, S; Kumar, A V; Tripathi, R M; Sastry, V N

2001-02-01

The trace element contents of five varieties of instant coffee powder available in the Indian market have been analysed. Ca, Cr, Fe, K, Mg, Mn, Ni, Sr, Zn and Pb, Cd, Cu have been determined using atomic absorption spectrophotometry and differential pulse anodic stripping voltammetry, respectively. The metal levels in the coffee powders observed in this study are comparable with those reported for green coffe beans (Arabica and Robusta variety) reported worldwide with the exception of Sr and Zn, which were on the lower side of the reported values. Concentrations of these metals have been converted into intake figures based on coffee consumption. The daily intakes of the above metals through ingestion of coffee are 1.4 mg, 1.58 microg, 124 microg, 41.5 mg, 4.9 mg, 17.9 microg, 2.9 microg, 3.8 microg, 12.5 microg, 0.2 microg, 0.03 microg and 15.5 microg, respectively. The values, which were compared with the total dietary, intake of metals through ingestion by the Mumbai population, indicate that the contribution from coffee is less than or around 1% for most of the elements except for Cr and Ni which are around 3%.

X-ray position detector and implementation in a mirror pointing servo system

DOEpatents

Rabedeau, Thomas A.; Van Campen, Douglas G.; Stefan, Peter M.

2016-04-05

An X-ray beam position and stability detector is provided having a first metal blade collinear with a second metal blade, where an edge of the first metal blade is opposite an edge of the second metal blade, where the first metal blade edge and the second metal blade edge are disposed along a centerline with respect to each other, where the metal blades are capable of photoelectron emission when exposed to an x-ray beam, a metal coating on the metal blades that is capable of enhancing the photoelectron emission, or suppressing energy-resonant contaminants, or enhancing the photoelectron emission and suppressing energy-resonant contaminants, a background shielding element having an electrode capable of suppressing photoelectron emission from spurious x-rays not contained in an x-ray beam of interest, and a photoelectron emission detector having an amplifier capable of detecting the photoelectron emission as a current signal.

Walking and Walkability: Is Wayfinding a Missing Link? Implications for Public Health Practice.

PubMed

Vandenberg, Ann E; Hunter, Rebecca H; Anderson, Lynda A; Bryant, Lucinda L; Hooker, Steven P; Satariano, William A

2016-02-01

Research on walking and walkability has yet to focus on wayfinding, the interactive, problem-solving process by which people use environmental information to locate themselves and navigate through various settings. We reviewed the literature on outdoor pedestrian-oriented wayfinding to examine its relationship to walking and walkability, 2 areas of importance to physical activity promotion. Our findings document that wayfinding is cognitively demanding and can compete with other functions, including walking itself. Moreover, features of the environment can either facilitate or impede wayfinding, just as environmental features can influence walking. Although there is still much to be learned about wayfinding and walking behaviors, our review helps frame the issues and lays out the importance of this area of research and practice.

Properties of vapor detector arrays formed through plasticization of carbon black-organic polymer composites.

PubMed

Koscho, Michael E; Grubbs, Robert H; Lewis, Nathan S

2002-03-15

Arrays of vapor detectors have been formed through addition of varying mass fractions of the plasticizer diethylene glycol dibenzoate to carbon black-polymer composites of poly(vinyl acetate) (PVAc) or of poly(N-vinylpyrrolidone). Addition of plasticizer in 5% mass fraction increments produced 20 compositionally different detectors from each polymer composite. Differences in vapor sorption and permeability that effected changes in the dc electrical resistance response of these compositionally different detectors allowed identification and classification of various test analytes using standard chemometric methods. Glass transition temperatures, Tg, were measured using differential scanning calorimetry for plasticized polymers having a mass fraction of 0, 0.10, 0.20, 0.30, 0.40, or 0.50 of plasticizer in the composite. The plasticized PVAc composites with Tg < 25 degrees C showed rapid responses at room temperature to all of the test analyte vapors studied in this work, whereas composites with Tg > 25 degrees C showed response times that were highly dependent on the polymer/analyte combination. These composites showed a discontinuity in the temperature dependence of their resistance, and this discontinuity provided a simple method for determining the Tg of the composite and for determining the temperature or plasticizer mass fraction above which rapid resistance responses could be obtained for all members of the test set of analyte vapors. The plasticization approach provides a method for achieving rapid detector response times as well as for producing a large number of chemically different vapor detectors from a limited number of initial chemical feedstocks.

A marching-walking hybrid induces step length adaptation and transfers to natural walking

PubMed Central

Long, Andrew W.; Finley, James M.

2015-01-01

Walking is highly adaptable to new demands and environments. We have previously studied adaptation of locomotor patterns via a split-belt treadmill, where subjects learn to walk with one foot moving faster than the other. Subjects learn to adapt their walking pattern by changing the location (spatial) and time (temporal) of foot placement. Here we asked whether we can induce adaptation of a specific walking pattern when one limb does not “walk” but instead marches in place (i.e., marching-walking hybrid). The marching leg's movement is limited during the stance phase, and thus certain sensory signals important for walking may be reduced. We hypothesized that this would produce a spatial-temporal strategy different from that of normal split-belt adaptation. Healthy subjects performed two experiments to determine whether they could adapt their spatial-temporal pattern of step lengths during the marching-walking hybrid and whether the learning transfers to over ground walking. Results showed that the hybrid group did adapt their step lengths, but the time course of adaptation and deadaption was slower than that for the split-belt group. We also observed that the hybrid group utilized a mostly spatial strategy whereas the split-belt group utilized both spatial and temporal strategies. Surprisingly, we found no significant difference between the hybrid and split-belt groups in over ground transfer. Moreover, the hybrid group retained more of the learned pattern when they returned to the treadmill. These findings suggest that physical rehabilitation with this marching-walking paradigm on conventional treadmills may produce changes in symmetry comparable to what is observed during split-belt training. PMID:25867742

Directional radiation detectors

DOEpatents

Dowell, Jonathan L.

2017-09-12

Directional radiation detectors and systems, methods, and computer-readable media for using directional radiation detectors to locate a radiation source are provided herein. A directional radiation detector includes a radiation sensor. A radiation attenuator partially surrounds the radiation sensor and defines an aperture through which incident radiation is received by the radiation sensor. The aperture is positioned such that when incident radiation is received directly through the aperture and by the radiation sensor, a source of the incident radiation is located within a solid angle defined by the aperture. The radiation sensor senses at least one of alpha particles, beta particles, gamma particles, or neutrons.

Dalfampridine Effects Beyond Walking Speed in Multiple Sclerosis

PubMed Central

Fjeldstad, Cecilie; Suárez, Gustavo; Klingler, Michael; Henney, Herbert R.; Rabinowicz, Adrian L.

2015-01-01

Background: Dalfampridine extended release (ER) improves walking in people with multiple sclerosis (MS), as demonstrated by walking speed improvement. This exploratory study evaluated treatment effects of dalfampridine-ER on gait, balance, and walking through treatment withdrawal and reinitiation. Methods: Dalfampridine-ER responders, based on Timed 25-Foot Walk (T25FW) assessment before study entry, were included in this open-label, three-period, single-center study. Period 1: on-drug evaluations performed at screening and 1 week after screening. Period 2: dalfampridine-ER withdrawal and off-drug evaluations (days 5 and 11). Period 3: dalfampridine-ER reinitiation/final on-drug evaluation (day 15). Primary outcome variables: NeuroCom composite scores for gait and balance; balance was evaluated if gait changes were significant. Secondary variables: individual NeuroCom scores, walking speed (T25FW) and distance (2-Minute Walk Test [2MWT]), and balance (Berg Balance Scale [BBS]). Results: All 20 patients completed the study: mean age, 53.1 years; mean MS duration, 11.3 years; mean time taking dalfampridine-ER, 315.3 days. NeuroCom gait composite scores worsened during period 2 relative to period 1 and improved during period 3; the mean ± SD difference in gait composite scores on drug was 4.03 ± 1.51 points (P = .015). Balance composite scores did not change significantly. Improvements were observed for off-drug versus on-drug for T25FW (0.36 ft/sec, P < .001), 2MWT (25.4 ft, P = .006), and BBS (1.7 points, P = .003). Safety profile was consistent with previous studies. Conclusions: Significant improvements in gait, walking speed, distance, and balance were demonstrated by dalfampridine-ER reinitiation after a 10-day withdrawal period. PMID:26664333

When Human Walking is a Random Walk

NASA Astrophysics Data System (ADS)

Hausdorff, J. M.

1998-03-01

The complex, hierarchical locomotor system normally does a remarkable job of controlling an inherently unstable, multi-joint system. Nevertheless, the stride interval --- the duration of a gait cycle --- fluctuates from one stride to the next, even under stationary conditions. We used random walk analysis to study the dynamical properties of these fluctuations under normal conditions and how they change with disease and aging. Random walk analysis of the stride-to-stride fluctuations of healthy, young adult men surprisingly reveals a self-similar pattern: fluctuations at one time scale are statistically similar to those at multiple other time scales (Hausdorff et al, J Appl Phsyiol, 1995). To study the stability of this fractal property, we analyzed data obtained from healthy subjects who walked for 1 hour at their usual pace, as well as at slower and faster speeds. The stride interval fluctuations exhibited long-range correlations with power-law decay for up to a thousand strides at all three walking rates. In contrast, during metronomically-paced walking, these long-range correlations disappeared; variations in the stride interval were uncorrelated and non-fractal (Hausdorff et al, J Appl Phsyiol, 1996). To gain insight into the mechanism(s) responsible for this fractal property, we examined the effects of aging and neurological impairment. Using detrended fluctuation analysis (DFA), we computed α, a measure of the degree to which one stride interval is correlated with previous and subsequent intervals over different time scales. α was significantly lower in healthy elderly subjects compared to young adults (p < .003) and in subjects with Huntington's disease, a neuro-degenerative disorder of the central nervous system, compared to disease-free controls (p < 0.005) (Hausdorff et al, J Appl Phsyiol, 1997). α was also significantly related to degree of functional impairment in subjects with Huntington's disease (r=0.78). Recently, we have observed that just as

Relationship between objectively measured walkability and exercise walking among adults with diabetes.

PubMed

Hosler, Akiko S; Gallant, Mary P; Riley-Jacome, Mary; Rajulu, Deepa T

2014-01-01

Little is known about the relationship between objectively measured walkability and walking for exercise among adults with diabetes. Information regarding walking behavior of adults with diabetes residing in 3 Upstate New York counties was collected through an interview survey. Walkability measures were collected through an environmental audit of a sample of street segments. Overall walkability and 4 subgroup measures of walkability were aggregated at the ZIP level. Multivariate logistic regression was used for analysis. Study participants (n = 208) were 61.0% female, 56.7% non-Hispanic White, and 35.1% African-American, with a mean age of 62.0 years. 108 participants (51.9%) walked for exercise on community streets, and 62 (29.8%) met the expert-recommended level of walking for ≥150 minutes/week. After adjustment for age, gender, race/ethnicity, education, BMI, physical impairment, and social support for exercise, walking any minutes/week was associated with traffic safety (OR 1.34, 95% CI 1.15-1.65). Walking ≥150 minutes/week was associated with overall walkability of the community (2.65, 1.22, and 5.74), as well as sidewalks (1.73, 1.12-2.67), street amenity (2.04, 1.12-3.71), and traffic safety (1.92, 1.02-3.72). This study suggests that walkability of the community should be an integral part of the socioecologic approach to increase physical activity among adults with diabetes.

Application of an asymmetric flow field flow fractionation multi-detector approach for metallic engineered nanoparticle characterization--prospects and limitations demonstrated on Au nanoparticles.

PubMed

Hagendorfer, Harald; Kaegi, Ralf; Traber, Jacqueline; Mertens, Stijn F L; Scherrers, Roger; Ludwig, Christian; Ulrich, Andrea

2011-11-14

In this work we discuss about the method development, applicability and limitations of an asymmetric flow field flow fractionation (A4F) system in combination with a multi-detector setup consisting of UV/vis, light scattering, and inductively coupled plasma mass spectrometry (ICPMS). The overall aim was to obtain a size dependent-, element specific-, and quantitative method appropriate for the characterization of metallic engineered nanoparticle (ENP) dispersions. Thus, systematic investigations of crucial method parameters were performed by employing well characterized Au nanoparticles (Au-NPs) as a defined model system. For good separation performance, the A4F flow-, membrane-, and carrier conditions were optimized. To obtain reliable size information, the use of laser light scattering based detectors was evaluated, where an online dynamic light scattering (DLS) detector showed good results for the investigated Au-NP up to a size of 80 nm in hydrodynamic diameter. To adapt large sensitivity differences of the various detectors, as well as to guarantee long term stability and minimum contamination of the mass spectrometer a split-flow concept for coupling ICPMS was evaluated. To test for reliable quantification, the ICPMS signal response of ionic Au standards was compared to that of Au-NP. Using proper stabilization with surfactants, no difference for concentrations of 1-50 μg Au L(-1) in the size range from 5 to 80 nm for citrate stabilized dispersions was observed. However, studies using different A4F channel membranes showed unspecific particle-membrane interaction resulting in retention time shifts and unspecific loss of nanoparticles, depending on the Au-NP system as well as membrane batch and type. Thus, reliable quantification and discrimination of ionic and particular species was performed using ICPMS in combination with ultracentrifugation instead of direct quantification with the A4F multi-detector setup. Figures of merit were obtained, by comparing the

Tuning of Muscle Synergies During Walking Along Rectilinear and Curvilinear Trajectories in Humans.

PubMed

Chia Bejarano, Noelia; Pedrocchi, Alessandra; Nardone, Antonio; Schieppati, Marco; Baccinelli, Walter; Monticone, Marco; Ferrigno, Giancarlo; Ferrante, Simona

2017-05-01

The aim of this study was to develop a methodology based on muscle synergies to investigate whether rectilinear and curvilinear walking shared the same neuro-motor organization, and how this organization was fine-tuned by the walking condition. Thirteen healthy subjects walked on rectilinear and curvilinear paths. Electromyographic data from thirteen back and lower-limb muscles were acquired, together with kinematic data using inertial sensors. Four macroscopically invariant muscle synergies, extracted through non-negative matrix factorization, proved a shared modular organization across conditions. The fine-tuning of muscle synergies was studied through non-negative matrix reconstruction, applied by fixing muscle weights or activation profiles to those of the rectilinear condition. The activation profiles tended to be recruited for a longer period and with a larger amplitude during curvilinear walking. The muscles of the posterior side of the lower limb were those mainly influenced by the fine-tuning, with the muscles inside the rotation path being more active than the outer muscles. This study shows that rectilinear and curvilinear walking share a unique motor command. However, a fine-tuning in muscle synergies is introduced during curvilinear conditions, adapting the kinematic strategy to the new biomechanical needs.

Exploring Associations Between Perceived Measures of the Environment and Walking Among Brazilian Older Adults.

PubMed

Corseuil Giehl, Maruí W; Hallal, Pedro C; Brownson, Ross C; d'Orsi, Eleonora

2017-02-01

To investigate the associations between perceived environment features and walking in older adults. A cross-sectional population-based study was performed in Florianopolis, Brazil, including 1,705 older adults (60+ years). Walking was measured by the International Physical Activity Questionnaire (IPAQ), and perceived environment was assessed through the Neighborhood Environment Walkability Scale. We conducted a multinomial logistic regression to examine the association between perceived environment and walking. The presence of sidewalks was related to both walking for transportation and for leisure. Existence of crosswalks in the neighborhood, safety during the day, presence of street lighting, recreational facilities, and having dog were significant predictors of walking for transportation. Safety during the day and social support were significantly associated with walking for leisure. The perceived environment may affect walking for specific purposes among older adults. Investments in the environment may increase physical activity levels of older adults in Brazil.

Gamma ray detector shield

DOEpatents

Ohlinger, R.D.; Humphrey, H.W.

1985-08-26

A gamma ray detector shield comprised of a rigid, lead, cylindrical-shaped vessel having upper and lower portions with an pneumatically driven, sliding top assembly. Disposed inside the lead shield is a gamma ray scintillation crystal detector. Access to the gamma detector is through the sliding top assembly.

Tin-gallium-oxide-based UV-C detectors

NASA Astrophysics Data System (ADS)

Mukhopadhyay, Partha; Toporkov, Mykyta; Schoenfeld, Winston V.

2018-02-01

The emergence of conductive gallium oxide single crystal substrates offers the potential for vertical Schottky detectors operating in the UV-C spectral region. We report here on our recent work in the development of Tin Gallium oxide (TGO) thin film metal-semiconductor-metal (MSM) and Schottky detectors using plasma-assisted molecular beam epitaxy on c plane sapphire and bulk Ga2O3 substrates. Tin alloying of gallium oxide thin films was found to systematically reduce the optical band gap of the compound, providing tunability in the UV-C spectral region. Tin concentration in the TGO epilayers was found to be highly dependent on growth conditions, and Ga flux in particular. First attempts to demonstrate vertical Schottky photodetectors using TGO epilayers on bulk n-type Ga2O3 substrates were successful. Resultant devices showed strong photoresponse to UV-C light with peak responsivities clearly red shifted in comparison to Ga2O3 homoepitaxial Schottky detectors due to TGO alloying.

Walking beam furnace well-way slot covers at Rouge Steel

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

Campbell, F. Jr.; Meinzinger, A.D.; Faust, C.H.

1993-07-01

Rouge Steel's 68-in. hot strip mill is served by three walking beam slab reheat furnaces. The first two were commissioned in 1974 and the third was installed in 1980. During the period 1979 to 1981, an intensive plant-wide energy management program to reduce energy consumption was undertaken. A major part of that program involved a comprehensive upgrading of refractory and insulation systems utilized in the walking beam reheat furnaces. A durable system for reducing heat losses through the well-way floor openings associated with walking beam slab reheat furnaces has, in addition to 4 to 5% savings in fuel consumption, reducedmore » maintenance costs. Payback is achieved in four to five months.« less

Aerobic treadmill plus Bobath walking training improves walking in subacute stroke: a randomized controlled trial.

PubMed

Eich, H-J; Mach, H; Werner, C; Hesse, S

2004-09-01

To evaluate the immediate and long-term effects of aerobic treadmill plus Bobath walking training in subacute stroke survivors compared with Bobath walking training alone. Randomized controlled trial. Rehabilitation unit. Fifty patients, first-time supratentorial stroke, stroke interval less than six weeks, Barthel Index (0-100) from 50 to 80, able to walk a minimum distance of 12 m with either intermittent help or stand-by while walking, cardiovascular stable, minimum 50 W in the bicycle ergometry, randomly allocated to two groups, A and B. Group A 30 min of treadmill training, harness secured and minimally supported according to patients' needs, and 30 min of physiotherapy, every workday for six weeks, speed and inclination of the treadmill were adjusted to achieve a heart rate of HR: (Hrmax-HRrest)*0.6+HRrest; in group B 60 min of daily physiotherapy for six weeks. Primary outcome variables were the absolute improvement of walking velocity (m/s) and capacity (m), secondary were gross motor function including walking ability (score out of 13) and walking quality (score out of 41), blindly assessed before and after the intervention, and at follow-up three months later. Patients tolerated the aerobic training well with no side-effects, significantly greater improvement of walking velocity and capacity both at study end (p =0.001 versus p =0.002) and at follow-up (p <0.001 versus p <0.001) in the experimental group. Between weeks 0 and 6, the experimental group improved walking speed and capacity by a mean of.31 m/s and 91 m, the control group by a mean of 0.16 m/s and 56 m. Between weeks 0 and 18, the experimental group improved walking speed and capacity by a mean of 0.36 m/s and 111 m, the control group by a mean of 0.15 m/s and 57 m. Gross motor function and walking quality did not differ at any time. Aerobic treadmill plus Bobath walking training in moderately affected stroke patients was better than Bobath walking training alone with respect to the improvement

Walking the Tightrope: Colloidal surfers mimicking molecular motors

NASA Astrophysics Data System (ADS)

Horowitz, Viva R.; Driscoll, Michelle; Ferrari, Melissa; Youssef, Mena; Sacanna, Stefano; Chaikin, Paul; Manoharan, Vinothan N.

We aim to understand cellular processes, particularly intracellular transport, at a physical level by building simple, well-\\x90controlled systems that mimic the functions of a cell. We are inspired by molecular motors such as kinesin and myosin, which create a dynamic environment that is likely necessary for the biochemical reactions that take place in a eukaryotic cell. One approach we have taken is to investigate the superdiffusive environment created by platinum Janus swimmers encapsulated in artificial cells. Now we are investigating the motion of light-activated colloidal surfers. When they are activated, these particles are attracted to each other and to surfaces, and they are self-propelled, moving via self-diffusiophoresis. On a flat surface, these properties cause the particles to form active crystal structures. When we introduce a wire to the geometry, the particles walk along a wire, reminiscent of the motion of molecular motors such as kinesin walking on a microtubule. When the wire is suspended in the center of a fluid chamber, the particles walk the tightrope. This bio-inspired research may lead to systems of particles walking networks of wires and carrying cargo through an artificial cell.

CRiT Walking in Higher Education: Activating Critical Race Theory in the Academy

ERIC Educational Resources Information Center

Hughes, Robin; Giles, Mark

2010-01-01

In this article, the authors introduce the epistemological concept of CRiT walking based on critical race theory (CRT). Using performance methodology, an operational extension of critical race theory is introduced as a CRiT walk through academic neighborhoods. The authors recommend openly questioning the structural inequities deeply embedded…

Dog ownership, dog walking, and leisure-time walking among Taiwanese metropolitan and nonmetropolitan older adults.

PubMed

Liao, Yung; Huang, Pin-Hsuan; Chen, Yi-Ling; Hsueh, Ming-Chun; Chang, Shao-Hsi

2018-04-04

This study examined the prevalence of dog ownership and dog walking and its association with leisure-time walking among metropolitan and nonmetropolitan older adults. A telephone-based cross-sectional survey targeting Taiwanese older adults was conducted in November 2016. Data related to dog ownership, time spent dog walking (categorized as non-dog owner, non-dog walkers, and dog walkers), and sociodemographic variables were obtained from 1074 older adults. Adjusted binary logistic regression was then performed. In this sample, 12% of Taiwanese older adults owned a dog and 31% of them walked their dogs for an average of 232.13 min over 5.9 days/week (standard deviation = 2.03). Older adults living in nonmetropolitan areas were more likely to own a dog (14.7% vs. 9.1%) but less likely to walk their dog (25.9% vs. 39.6%) than were those living in metropolitan areas. Compared with non-dog owners, only older adults living in nonmetropolitan areas who were dog walkers achieved 150 min of leisure-time walking (odds ratio: 3.03, 95% confidence interval: 1.05-8.77), after adjustment for potential confounders. Older Taiwanese adults living in nonmetropolitan areas who owned and walked their dogs were more likely to achieve health-enhancing levels of leisure-time walking. Tailored physical activity interventions for promoting dog walking should be developed for older adults who are dog owners living in nonmetropolitan areas and who do not engage in dog walking.

Look who's walking: social and environmental correlates of children's walking in London.

PubMed

Steinbach, Rebecca; Green, Judith; Edwards, Phil

2012-07-01

A substantial literature examines the social and environmental correlates of walking to school but less addresses walking outside the school commute. Using travel diary data from London, we examined social and environmental correlates of walking: to school; outside the school commute during term time; and during the summer and weekends. Living in a household without a car was associated with all journey types; 'Asian' ethnicity was negatively associated with walking for non-school travel; environmental factors were associated with non-school journeys, but not the school commute. Interventions aiming to increase children's active travel need to take account of the range of journeys they make. Copyright © 2012 Elsevier Ltd. All rights reserved.

Amorphous Silicon Based Neutron Detector

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

Xu, Liwei

2004-12-12

Various large-scale neutron sources already build or to be constructed, are important for materials research and life science research. For all these neutron sources, neutron detectors are very important aspect. However, there is a lack of a high-performance and low-cost neutron beam monitor that provides time and temporal resolution. The objective of this SBIR Phase I research, collaboratively performed by Midwest Optoelectronics, LLC (MWOE), the University of Toledo (UT) and Oak Ridge National Laboratory (ORNL), is to demonstrate the feasibility for amorphous silicon based neutron beam monitors that are pixilated, reliable, durable, fully packaged, and fabricated with high yield usingmore » low-cost method. During the Phase I effort, work as been focused in the following areas: 1) Deposition of high quality, low-defect-density, low-stress a-Si films using very high frequency plasma enhanced chemical vapor deposition (VHF PECVD) at high deposition rate and with low device shunting; 2) Fabrication of Si/SiO2/metal/p/i/n/metal/n/i/p/metal/SiO2/ device for the detection of alpha particles which are daughter particles of neutrons through appropriate nuclear reactions; and 3) Testing of various devices fabricated for alpha and neutron detection; As the main results: · High quality, low-defect-density, low-stress a-Si films have been successfully deposited using VHF PECVD on various low-cost substrates; · Various single-junction and double junction detector devices have been fabricated; · The detector devices fabricated have been systematically tested and analyzed. · Some of the fabricated devices are found to successfully detect alpha particles. Further research is required to bring this Phase I work beyond the feasibility demonstration toward the final prototype devices. The success of this project will lead to a high-performance, low-cost, X-Y pixilated neutron beam monitor that could be used in all of the neutron facilities worldwide. In addition, the

Effect of type of cognitive task and walking speed on cognitive-motor interference during dual-task walking.

PubMed

Patel, P; Lamar, M; Bhatt, T

2014-02-28

We aimed to determine the effect of distinctly different cognitive tasks and walking speed on cognitive-motor interference of dual-task walking. Fifteen healthy adults performed four cognitive tasks: visuomotor reaction time (VMRT) task, word list generation (WLG) task, serial subtraction (SS) task, and the Stroop (STR) task while sitting and during walking at preferred-speed (dual-task normal walking) and slow-speed (dual-task slow-speed walking). Gait speed was recorded to determine effect on walking. Motor and cognitive costs were measured. Dual-task walking had a significant effect on motor and cognitive parameters. At preferred-speed, the motor cost was lowest for the VMRT task and highest for the STR task. In contrast, the cognitive cost was highest for the VMRT task and lowest for the STR task. Dual-task slow walking resulted in increased motor cost and decreased cognitive cost only for the STR task. Results show that the motor and cognitive cost of dual-task walking depends heavily on the type and perceived complexity of the cognitive task being performed. Cognitive cost for the STR task was low irrespective of walking speed, suggesting that at preferred-speed individuals prioritize complex cognitive tasks requiring higher attentional and processing resources over walking. While performing VMRT task, individuals preferred to prioritize more complex walking task over VMRT task resulting in lesser motor cost and increased cognitive cost for VMRT task. Furthermore, slow walking can assist in diverting greater attention towards complex cognitive tasks, improving its performance while walking. Copyright © 2013 IBRO. Published by Elsevier Ltd. All rights reserved.

Integrated system for single leg walking

NASA Astrophysics Data System (ADS)

Simmons, Reid; Krotkov, Eric; Roston, Gerry

1990-07-01

The Carnegie Mellon University Planetary Rover project is developing a six-legged walking robot capable of autonomously navigating, exploring, and acquiring samples in rugged, unknown environments. This report describes an integrated software system capable of navigating a single leg of the robot over rugged terrain. The leg, based on an early design of the Ambler Planetary Rover, is suspended below a carriage that slides along rails. To walk, the system creates an elevation map of the terrain from laser scanner images, plans an appropriate foothold based on terrain and geometric constraints, weaves the leg through the terrain to position it above the foothold, contacts the terrain with the foot, and applies force enough to advance the carriage along the rails. Walking both forward and backward, the system has traversed hundreds of meters of rugged terrain including obstacles too tall to step over, trenches too deep to step in, closely spaced obstacles, and sand hills. The implemented system consists of a number of task-specific processes (two for planning, two for perception, one for real-time control) and a central control process that directs the flow of communication between processes.

Walking speed and peak plantar pressure distribution during barefoot walking in persons with diabetes.

PubMed

Ko, Mansoo; Hughes, Lynne; Lewis, Harriet

2012-03-01

The impact of walking speed has not been evaluated as a feasible outcome measure associated with peak plantar pressure (PPP) distribution, which may result in tissue damage in persons with diabetic foot complications. The objective of this pilot study was to determine the walking speed and PPP distribution during barefoot walking in persons with diabetes.   Nine individuals with diabetes and nine age-gender matched individuals without diabetes participated in this study. Each individual was marked at 10 anatomical landmarks for vibration and tactile pressure sensation tests to determine the severity of sensory deficits on the plantar surface of the dominant limb foot. A steady state walking speed, PPP, the fore and rear foot (F/R) PPP ratio and gait variables were measured during barefoot walking.   Persons with diabetes had a significantly slower walking speed than the age-gender matched group resulting in a significant reduction of PPP at the F/R foot during barefoot walking (p < 0.05). There was no significant difference in F/R foot PPP ratio in the diabetic group compared with the age-gender matched group during barefoot walking (p > 0.05). There was a significant difference between the diabetic and non-diabetic groups for cadence, step time, toe out angle and the anterior-posterior excursion (APE) for centre of force (p < 0.05).   Walking speed may be a potential indicator for persons with diabetes to identify PPP distribution during barefoot walking in a diabetic foot. However, the diabetic group demonstrated a more cautious walking pattern than the age-gender matched group by decreasing cadence, step length and APE, and increasing step time and toe in/out angle. People with diabetes may reduce the risk of foot ulcerations as long as they are able to prevent severe foot deformities such as callus, hammer toe or charcot foot. Copyright © 2011 John Wiley & Sons, Ltd.

The influence of personal patterns of behavior on the physiological effects of woodland walking.

PubMed

Toda, Masahiro; Takeshita, Tatsuya

2015-01-01

The effects of forest walking are once again being recognized; however, few studies have investigated individual variations in the effects of forest walking. The objective of the current study was to investigate the influence of individual patterns of behavior on the physiological effects of walking through woodland. The study employed a crossover, open-label, single-group, self-controlled design. This study was conducted in the forest on Ikoma Mountain, at the eastern edge of Osaka Prefecture in Japan. Participants were 20 healthy males, selected randomly from a population of members at a nonprofit organization with a mean age of 67.6 y. Moving from the start of a mountain path to an observation platform, participants took a 1000-m walk through the forest. On another day, participants remained in their offices. Patterns of personal behavior were assessed preintervention by written questionnaire, identifying type A and type B behavior patterns. Salivary chromogranin A (CgA) levels were determined immediately before and after the walk as well as at 20 min after and 40 min after its end. On the day when participants sat in their offices, control samples were collected at the same times as on the day of the walk. In the type B-behavior pattern group, a significant increase in the levels of CgA occurred after the walk. No change was observed in the type A-behavior pattern group. The findings suggest that walking in woodland may bring about positive health benefits, particularly to individuals with type B characteristics.

Walking with a Slower Friend

ERIC Educational Resources Information Center

Bailey, Herb; Kalman, Dan

2011-01-01

Fay and Sam go for a walk. Sam walks along the left side of the street while Fay, who walks faster, starts with Sam but walks to a point on the right side of the street and then returns to meet Sam to complete one segment of their journey. We determine Fay's optimal path minimizing segment length, and thus maximizing the number of times they meet…

Walking-age analyzer for healthcare applications.

PubMed

Jin, Bo; Thu, Tran Hoai; Baek, Eunhye; Sakong, SungHwan; Xiao, Jin; Mondal, Tapas; Deen, M Jamal

2014-05-01

This paper describes a walking-age pattern analysis and identification system using a 3-D accelerometer and a gyroscope. First, a walking pattern database from 79 volunteers of ages ranging from 10 to 83 years is constructed. Second, using feature extraction and clustering, three distinct walking-age groups, children of ages 10 and below, adults in 20-60s, and elders in 70s and 80s, were identified. For this study, low-pass filtering, empirical mode decomposition, and K-means were used to process and analyze the experimental results. Analysis shows that volunteers' walking-ages can be categorized into distinct groups based on simple walking pattern signals. This grouping can then be used to detect persons with walking patterns outside their age groups. If the walking pattern puts an individual in a higher "walking age" grouping, then this could be an indicator of potential health/walking problems, such as weak joints, poor musculoskeletal support system or a tendency to fall.

Fractal modeling of fluidic leakage through metal sealing surfaces

NASA Astrophysics Data System (ADS)

Zhang, Qiang; Chen, Xiaoqian; Huang, Yiyong; Chen, Yong

2018-04-01

This paper investigates the fluidic leak rate through metal sealing surfaces by developing fractal models for the contact process and leakage process. An improved model is established to describe the seal-contact interface of two metal rough surface. The contact model divides the deformed regions by classifying the asperities of different characteristic lengths into the elastic, elastic-plastic and plastic regimes. Using the improved contact model, the leakage channel under the contact surface is mathematically modeled based on the fractal theory. The leakage model obtains the leak rate using the fluid transport theory in porous media, considering that the pores-forming percolation channels can be treated as a combination of filled tortuous capillaries. The effects of fractal structure, surface material and gasket size on the contact process and leakage process are analyzed through numerical simulations for sealed ring gaskets.

Effect of uphill and downhill walking on walking performance in geriatric patients using a wheeled walker.

PubMed

Lindemann, Ulrich; Schwenk, Michael; Schmitt, Syn; Weyrich, Michael; Schlicht, Wolfgang; Becker, Clemens

2017-08-01

Wheeled walkers are recommended to improve walking performance in older persons and to encourage and assist participation in daily life. Nevertheless, using a wheeled walker can cause serious problems in the natural environment. This study aimed to compare uphill and downhill walking with walking level in geriatric patients using a wheeled walker. Furthermore, we investigated the effect of using a wheeled walker with respect to dual tasking when walking level. A total of 20 geriatric patients (median age 84.5 years) walked 10 m at their habitual pace along a level surface, uphill and downhill, with and without a standard wheeled walker. Gait speed, stride length and cadence were assessed by wearable sensors and the walk ratio was calculated. When using a wheeled walker while walking level the walk ratio improved (0.58 m/[steps/min] versus 0.57 m/[steps/min], p = 0.023) but gait speed decreased (1.07 m/s versus 1.12 m/s, p = 0.020) when compared to not using a wheeled walker. With respect to the walk ratio, uphill and downhill walking with a wheeled walker decreased walking performance when compared to level walking (0.54 m/[steps/min] versus 0.58 m/[steps/min], p = 0.023 and 0.55 m/[steps/min] versus 0.58 m/[steps/min], p = 0.001, respectively). At the same time, gait speed decreased (0.079 m/s versus 1.07 m/s, p < 0.0001) or was unaffected. The use of a wheeled walker improved the quality of level walking but the performance of uphill and downhill walking was worse compared to walking level when using a wheeled walker.

[Objective evaluation of arterial intermittent claudication by the walking tolerance test. Comparative study of physiological walking and walking on a conveyor belt (author's transl)].

PubMed

Bouchet, J Y; Franco, A; Morzol, B; Beani, J C

1980-01-01

Two methods are used to evaluate the walking distance: physiological walking along a standard path (0% - 6 mk/h) and walking on a tread mill (10% - 3 km/h). In both tests, four data are checked: -- initial trouble distance, -- cramp or walking-distance, -- localisation of pain, -- recovery time. These tests are dependable for the diagnosis of arterial claudication, reproducible and well tolerated. Their results have been compared: there is no correlation between the initial trouble distance and the cramp distance. However there is a correlation between the cramp distance by physiological walking and on treadmill. Recovery time, if long, is a criteria of gravity. Interests of both methods are discussed.

Metal artifact reduction through MVCBCT and kVCT in radiotherapy

NASA Astrophysics Data System (ADS)

Liugang, Gao; Hongfei, Sun; Xinye, Ni; Mingming, Fang; Zheng, Cao; Tao, Lin

2016-11-01

This study proposes a new method for removal of metal artifacts from megavoltage cone beam computed tomography (MVCBCT) and kilovoltage CT (kVCT) images. Both images were combined to obtain prior image, which was forward projected to obtain surrogate data and replace metal trace in the uncorrected kVCT image. The corrected image was then reconstructed through filtered back projection. A similar radiotherapy plan was designed using the theoretical CT image, the uncorrected kVCT image, and the corrected image. The corrected images removed most metal artifacts, and the CT values were accurate. The corrected image also distinguished the hollow circular hole at the center of the metal. The uncorrected kVCT image did not display the internal structure of the metal, and the hole was misclassified as metal portion. Dose distribution calculated based on the corrected image was similar to that based on the theoretical CT image. The calculated dose distribution also evidently differed between the uncorrected kVCT image and the theoretical CT image. The use of the combined kVCT and MVCBCT to obtain the prior image can distinctly improve the quality of CT images containing large metal implants.

Chelate-Assisted Heavy Metal Movement Through the Root Zone

NASA Astrophysics Data System (ADS)

Kirkham, M.; Madrid, F.; Liphadzi, M. S.

2001-12-01

Chelating agents are added to soil as a means to mobilize heavy metals for plant uptake during phytoremediation. Yet almost no studies follow the displacement of heavy metals through the vadose zone following solubilization with chelating agents. The objective of this work was to determine the movement of heavy metals through the soil profile and their absorption by barley (Hordeum vulgare L.) in a soil amended with biosolids and in the presence of a chelating agent (EDTA). Twelve columns 75 cm in height and 17 in diameter were packed with a Haynie very fine sandy loam (coarse-silty, mixed, calcareous, mesic Mollic Udifluvents) and watered with liquid biosolids applied at the surface at a rate of 120 kg N/ha. Three weeks after plants germinated, soil was irrigated with a solution of the disodium salt of EDTA added at a rate of 0.5 g/kg soil. Four treatments were imposed: columns with no plants and no EDTA; columns with no plants plus EDTA; columns with plants and no EDTA; and columns with plants and EDTA. Columns were watered intensively for 35 days until two pore volumes of water had been added, and the leachates were collected daily. With or without plants, columns with EDTA had lower total concentrations of Cu, Zn, Cd, Ni, and Pb in the surface 20 cm than columns without EDTA. Concentrations of the heavy metals in this layer were not afffected by the presence of roots. Iron in leachate was followed as an indicator metal for movement to groundwater. No iron appeared in the leachate without EDTA, either in the columns with plants or without plants. The peak concentration of iron in the leachate occurred three days earlier in the columns without plants and EDTA compared to the columns with plants and EDTA. The results indicated the importance of vegetation on retarding heavy metal leaching to groundwater during chelate-facilitated phytoremediation.

Walk-through survey report, Gulfstream American Corporation (formerly Grumman-American Aviation Corp. ) Savannah, Georgia

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

Matanoski, G.; Billings, C.; Levine, M.

1979-05-01

The four major paint shops (light aircraft, small parts, Colar anticorrosive primer, and the Alodine epoxy/phenolic resin paint shop) employing 30 workers at Gulfstream American Corporation, Savannah, Georgia were the primary focus of a walk-through on July 12 and 13, 1978. The company's record-keeping system, medical program, and industrial-hygiene program were examined. The authors recommend that the light aircraft paint shop be included in an industrial hygiene study since the workload is fairly steady, types of paints and peripheral exposures are easily documented, and current control measures result in relatively low exposures of personnel to paint constituents. An epidemiological studymore » is not recommended because the facility is new and the number of painters and the duration of exposures are limited. The authors suggest that this factory be considered during the final selection of aircraft manufacturing facilities for medical studies because of the degree of potential exposure to polyurethane paint.« less

Separation of metal ions from aqueous solutions

DOEpatents

Almon, Amy C.

1994-01-01

A process and apparatus for quantitatively and selectively separating metal ions from mixtures thereof in aqueous solution. The apparatus includes, in combination, a horizontal electrochemical flow cell containing flow bulk electrolyte solution and an aqueous, metal ion-containing solution, the cell containing a metal mesh working electrode, a counter electrode positioned downstream from the working electrode, an independent variable power supply/potentiostat positioned outside of the flow cell and connected to the electrodes, and optionally a detector such as a chromatographic detector, positioned outside the flow cell. This apparatus and its operation has significant application where trace amounts of metal ions are to be separated.

Random walks and diffusion on networks

NASA Astrophysics Data System (ADS)

Masuda, Naoki; Porter, Mason A.; Lambiotte, Renaud

2017-11-01

Random walks are ubiquitous in the sciences, and they are interesting from both theoretical and practical perspectives. They are one of the most fundamental types of stochastic processes; can be used to model numerous phenomena, including diffusion, interactions, and opinions among humans and animals; and can be used to extract information about important entities or dense groups of entities in a network. Random walks have been studied for many decades on both regular lattices and (especially in the last couple of decades) on networks with a variety of structures. In the present article, we survey the theory and applications of random walks on networks, restricting ourselves to simple cases of single and non-adaptive random walkers. We distinguish three main types of random walks: discrete-time random walks, node-centric continuous-time random walks, and edge-centric continuous-time random walks. We first briefly survey random walks on a line, and then we consider random walks on various types of networks. We extensively discuss applications of random walks, including ranking of nodes (e.g., PageRank), community detection, respondent-driven sampling, and opinion models such as voter models.

Evaluation of a metal artifact reduction algorithm applied to post-interventional flat detector CT in comparison to pre-treatment CT in patients with acute subarachnoid haemorrhage.

PubMed

Mennecke, Angelika; Svergun, Stanislav; Scholz, Bernhard; Royalty, Kevin; Dörfler, Arnd; Struffert, Tobias

2017-01-01

Metal artefacts can impair accurate diagnosis of haemorrhage using flat detector CT (FD-CT), especially after aneurysm coiling. Within this work we evaluate a prototype metal artefact reduction algorithm by comparison of the artefact-reduced and the non-artefact-reduced FD-CT images to pre-treatment FD-CT and multi-slice CT images. Twenty-five patients with acute aneurysmal subarachnoid haemorrhage (SAH) were selected retrospectively. FD-CT and multi-slice CT before endovascular treatment as well as FD-CT data sets after treatment were available for all patients. The algorithm was applied to post-treatment FD-CT. The effect of the algorithm was evaluated utilizing the pre-post concordance of a modified Fisher score, a subjective image quality assessment, the range of the Hounsfield units within three ROIs, and the pre-post slice-wise Pearson correlation. The pre-post concordance of the modified Fisher score, the subjective image quality, and the pre-post correlation of the ranges of the Hounsfield units were significantly higher for artefact-reduced than for non-artefact-reduced images. Within the metal-affected slices, the pre-post slice-wise Pearson correlation coefficient was higher for artefact-reduced than for non-artefact-reduced images. The overall diagnostic quality of the artefact-reduced images was improved and reached the level of the pre-interventional FD-CT images. The metal-unaffected parts of the image were not modified. • After coiling subarachnoid haemorrhage, metal artefacts seriously reduce FD-CT image quality. • This new metal artefact reduction algorithm is feasible for flat-detector CT. • After coiling, MAR is necessary for diagnostic quality of affected slices. • Slice-wise Pearson correlation is introduced to evaluate improvement of MAR in future studies. • Metal-unaffected parts of image are not modified by this MAR algorithm.

Microwave transmission through metallic hole arrays: Surface electric field measurements

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

Hou Bo; Hang Zhihong; Wen Weijia

2006-09-25

The authors investigate the enhanced microwave transmission through a metal plate perforated by a square lattice of subwavelength holes, predicted to occur as a structure factor resonance phenomenon [F. J. Gracia de Abajo and J. J. Saenz, Phys. Rev. Lett. 95, 233901 (2005)]. By probing the surface electric field on the metallic plate at the peak transmission frequency, they establish the similarities and differences between the structure factor resonance and surface plasmon.

A community-wide media campaign to promote walking in a Missouri town.

PubMed

Wray, Ricardo J; Jupka, Keri; Ludwig-Bell, Cathy

2005-10-01

Engaging in moderate physical activity for 30 minutes five or more times per week substantially reduces the risk of coronary heart disease, stroke, colon cancer, diabetes, high blood pressure, and obesity, and walking is an easy and accessible way to achieve this goal. A theory-based mass media campaign promoted walking and local community-sponsored wellness initiatives through four types of media (billboard, newspaper, radio, and poster advertisements) in St Joseph, Mo, over 5 months during the summer of 2003. The Walk Missouri campaign was conducted in four phases: 1) formative research, 2) program design and pretesting, 3) implementation, and 4) impact assessment. Using a postcampaign-only, cross-sectional design, a telephone survey (N = 297) was conducted in St Joseph to assess campaign impact. Study outcomes were pro-walking beliefs and behaviors. One in three survey respondents reported seeing or hearing campaign messages on one or more types of media. Reported exposure to the campaign was significantly associated with two of four pro-walking belief scales (social and pleasure benefits) and with one of three community-sponsored activities (participation in a community-sponsored walk) controlling for demographic, health status, and environmental factors. Exposure was also significantly associated with one of three general walking behaviors (number of days per week walking) when controlling for age and health status but not when beliefs were introduced into the model, consistent with an a priori theoretical mechanism: the mediating effect of pro-walking beliefs on the exposure-walking association. These results suggest that a media campaign can enhance the success of community-based efforts to promote pro-walking beliefs and behaviors.

Photovoltaic radiation detector element

DOEpatents

Agouridis, Dimitrios C.

1983-01-01

A radiation detector element is formed of a body of semiconductor material, a coating on the body which forms a photovoltaic junction therewith, and a current collector consisting of narrow metallic strips, the aforesaid coating having an opening therein the edge of which closely approaches but is spaced from the current collector strips.

Handheld Metal Detectors: Nicaraguan Field Test Report

DTIC Science & Technology

2001-10-01

Electronic Sensors Directorate (NVESD), the Organization of American States (OAS) ( Organizacion de los Estados Americanos [OEA]), the Assistance...manufacturer�s instructional manual , against known targets and soil types to optimize the detector sensitivity. Operators were instructed to operate...operating manual in the training/calibration area. Once calibration was completed, the operators were required to spend some time working with the

Environmental factors influencing older adults' walking for transportation: a study using walk-along interviews.

PubMed

Van Cauwenberg, Jelle; Van Holle, Veerle; Simons, Dorien; Deridder, Riet; Clarys, Peter; Goubert, Liesbet; Nasar, Jack; Salmon, Jo; De Bourdeaudhuij, Ilse; Deforche, Benedicte

2012-07-10

Current knowledge on the relationship between the physical environment and walking for transportation among older adults (≥ 65 years) is limited. Qualitative research can provide valuable information and inform further research. However, qualitative studies are scarce and fail to include neighborhood outings necessary to study participants' experiences and perceptions while interacting with and interpreting the local social and physical environment. The current study sought to uncover the perceived environmental influences on Flemish older adults' walking for transportation. To get detailed and context-sensitive environmental information, it used walk-along interviews. Purposeful convenience sampling was used to recruit 57 older adults residing in urban or semi-urban areas. Walk-along interviews to and from a destination (e.g. a shop) located within a 15 minutes' walk from the participants' home were conducted. Content analysis was performed using NVivo 9 software (QSR International). An inductive approach was used to derive categories and subcategories from the data. Data were categorized in the following categories and subcategories: access to facilities (shops & services, public transit, connectivity), walking facilities (sidewalk quality, crossings, legibility, benches), traffic safety (busy traffic, behavior of other road users), familiarity, safety from crime (physical factors, other persons), social contacts, aesthetics (buildings, natural elements, noise & smell, openness, decay) and weather. The findings indicate that to promote walking for transportation a neighborhood should provide good access to shops and services, well-maintained walking facilities, aesthetically appealing places, streets with little traffic and places for social interaction. In addition, the neighborhood environment should evoke feelings of familiarity and safety from crime. Future quantitative studies should investigate if (changes in) these environmental factors relate to

Cosmic Ray Measurements by Scintillators with Metal Resistor Semiconductor Avalanche Photo Diodes

ERIC Educational Resources Information Center

Blanco, Francesco; La Rocca, Paola; Riggi, Francesco; Akindinov, Alexandre; Mal'kevich, Dmitry

2008-01-01

An educational set-up for cosmic ray physics experiments is described. The detector is based on scintillator tiles with a readout through metal resistor semiconductor (MRS) avalanche photo diode (APD) arrays. Typical measurements of the cosmic angular distribution at sea level and a study of the East-West asymmetry obtained by such a device are…

A Biomechanical Investigation of Selected Lumbopelvic Hip Tests: Implications for the Examination of Walking.

PubMed

Bailey, Robert Walter; Richards, Jim; Selfe, James

2016-01-01

The purpose of this study was to compare lumbopelvic hip ranges of motion during the Trendelenburg, Single Leg Squat, and Corkscrew Tests to walking and to describe the 3-dimensional lumbopelvic hip motion during the tests. This may help clinicians to select appropriate tests when examining gait. An optoelectronic movement analysis tracking system was used to assess the lumbopelvic hip region of 14 healthy participants while performing Trendelenburg, Single Leg Squat, and Corkscrew Tests and walking. The lumbopelvic hip 3-dimensional ranges of movement for the clinical tests were compared with walking using a repeated-measures analysis of variance with pairwise comparisons. No significant differences were found between the pelvic obliquity during the Trendelenburg Test and walking (Trendelenburg Test: L, 11.3° ± 4.8°, R, 10.8° ± 5.0° vs walk: L, 8.3° ± 4.8°, R 8.3° ± 5.1°, L, P = .143, R, P = .068). Significant differences were found between the hip sagittal plane range of movement during the Single Leg Squat and walking (Single Leg Squat: L, 44.2° ±13.7°, R, 41.7° ±10.9° vs walk: 38.6° ±7.0°, R 37.8° ±5.1°, P < .05), the hip coronal plane range of movement (Single Leg Squat: L, 9.1° ±5.8°, R, 9.0° ± 4.6° vs walk: L, 9.4° ± 2.3°, R 9.5° ± 2.0°, P < .05), and the hip coronal plane range of movement during the Corkscrew Test and walking (Corkscrew: L, 5.7° ±3.3°, R, 5.7° ±3.2° vs walk: L, 9.4° ± 2.3°, R 9.5° ± 2.0°, P < .05). The results of the present study showed that, in young asymptomatic participants with no known lumbopelvic hip pathology, the pelvic obliquity during the Trendelenburg Test and walking is similar. During the Single Leg Squat, the hip moved more in the sagittal plane and less in the coronal plane when compared with walking. There was more movement in the hip transverse plane movement during the Corkscrew Test than during walking. These results suggest that for the Trendelenburg Test to be

Thinking through every step: how people with spinal cord injuries relearn to walk.

PubMed

Jordan, Meggan M; Berkowitz, Dana; Hannold, Elizabeth; Velozo, Craig A; Behrman, Andrea L

2013-08-01

In this article we explore how people with incomplete spinal cord injury (iSCI) create meaning out of their changing bodies as they undergo a therapeutic intervention called locomotor training (LT). Therapeutic interventions like LT are used to promote the recovery of walking ability among individuals with iSCI. The chronological nature of this study--interviews at three points throughout the 12-week intervention--enhances understanding of the recovering self after spinal cord injury. Drawing on a constructivist theoretical framework, we organize data according to three narrative frames. Participants interpreted LT as (a) a physical change that was meaningful because of its social significance, (b) a coping strategy for dealing with the uncertainty of long-term recovery, and (c) a moral strategy to reconstitute the self. We offer findings that lay the conceptual groundwork for generating new knowledge about what is important to people with iSCI as they relearn how to walk.

The Bobath Concept in Walking Activity in Chronic Stroke Measured Through the International Classification of Functioning, Disability and Health.

PubMed

Benito García, Miguel; Atín Arratibel, María Ángeles; Terradillos Azpiroz, Maria Estíbaliz

2015-12-01

The aim of this study is to evaluate the effectiveness of a rehabilitation programme based on the Bobath concept in order to improve walking activity in patients with chronic stroke and to show the usefulness of the International Classification of Functioning, Disability and Health (ICF) as a tool for gathering functioning information. This study is a repeated measures study. The setting of this study is an outpatient neurological rehabilitation centre based on a multidisciplinary approach. Twenty-four participants suffering from chronic stroke (>1 year and a half and <5 years post-stroke) and mean age of 65.58 (standard deviation 10.73) were the participants of the study. Multidisciplinary approach based on the Bobath concept principles with three weekly individual physiotherapy sessions of 45 min each over a 6-month period was the intervention for this study. The measures used were Modified Emory Functional Ambulation Profile, 10-m walk test, 6-min walk test, muscle strength testing and subsequent codification of these results into ICF qualifiers. The results of the study showed significant improvement in activities of walking long distances, on different surfaces and around obstacles. There was no significant improvement in the activity of walking short distances or for muscle power functions. A rehabilitation programme based on the Bobath Concept improved walking activities in people with chronic stroke. For this intervention, the use of the ICF qualifiers was sensitive in perceiving post-treatment changes. Copyright © 2014 John Wiley & Sons, Ltd.

Microbial Diffraction Gratings as Optical Detectors for Heavy Metal Pollutants

NASA Technical Reports Server (NTRS)

Noever, David; Matsos, Helen; Brittain, Andrew; Obenhuber, Don; Cronise, Raymond; Armstrong, Shannon

1996-01-01

As a significant industrial pollutant, cadmium is implicated as the cause of itai-itai disease. For biological detection of cadmium toxicity, an assay device has been developed using the motile response of the protozoa species, Tetrahymena pyriformis. This mobile protozoa measures 50 microns in diameter, swims at 10 body lengths per second, and aggregates into macroscopically visible patterns at high organism concentrations. The assay demonstrates a Cd(+2) sensitivity better than 1 micro-M and a toxicity threshold to 5 micro-M, thus encouraging the study of these microbial cultures as viable pollution detectors. Using two-dimensional diffraction patterns within a Tetrahymena culture, the scattered light intensity varies with different organism densities (population counts). The resulting density profile correlates strongly with the toxic effects at very low dosages for cadmium (less than 5 ppm) and then for poison protection directly (with nickel and copper antagonists competing with cadmium absorption). In particular, copper dosages as low as 0.1-0.5 mM Cu have shown protective antagonism against cadmium, have enhanced density variability for cultures containing 1 mM Cd(+2) and therefore have demonstrated the sensitivity of the optical detection system. In this way, such microbial diffraction patterns give a responsive optical measure of biological culture changes and toxicity determination in aqueous samples of heavy metals and industrial pollutants.

Neuromorphic walking gait control.

PubMed

Still, Susanne; Hepp, Klaus; Douglas, Rodney J

2006-03-01

We present a neuromorphic pattern generator for controlling the walking gaits of four-legged robots which is inspired by central pattern generators found in the nervous system and which is implemented as a very large scale integrated (VLSI) chip. The chip contains oscillator circuits that mimic the output of motor neurons in a strongly simplified way. We show that four coupled oscillators can produce rhythmic patterns with phase relationships that are appropriate to generate all four-legged animal walking gaits. These phase relationships together with frequency and duty cycle of the oscillators determine the walking behavior of a robot driven by the chip, and they depend on a small set of stationary bias voltages. We give analytic expressions for these dependencies. This chip reduces the complex, dynamic inter-leg control problem associated with walking gait generation to the problem of setting a few stationary parameters. It provides a compact and low power solution for walking gait control in robots.

Human H-reflexes are smaller in difficult beam walking than in normal treadmill walking.

PubMed

Llewellyn, M; Yang, J F; Prochazka, A

1990-01-01

Hoffman (H) reflexes were elicited from the soleus (SOL) muscle while subjects walked on a treadmill and on a narrow beam (3.5 cm wide, raised 34 cm from the floor). The speed of walking on the treadmill was selected for each subject to match the background activation level of their SOL muscle during beam walking. The normal reciprocal activation pattern of the tibialis anterior and SOL muscles in treadmill walking was replaced by a pattern dominated by co-contraction on the beam. In addition, the step cycle duration was more variable and the time spent in the swing phase was reduced on the beam. The H-reflexes were highly modulated in both tasks, the amplitude being high in the stance phase and low in the swing phase. The H-reflex amplitude was on average 40% lower during beam walking than treadmill walking. The relationship between the H-reflex amplitude and the SOL EMG level was quantified by a regression line relating the two variables. The slope of this line was on average 41% lower in beam walking than treadmill walking. The lower H-reflex gain observed in this study and the high level of fusimotor drive observed in cats performing similar tasks suggest that the two mechanisms which control the excitability of this reflex pathway (i.e. fusimotor action and control of transmission at the muscle spindle to moto-neuron synapse) may be controlled independently.

Swing- and support-related muscle actions differentially trigger human walk-run and run-walk transitions.

PubMed

Prilutsky, B I; Gregor, R J

2001-07-01

There has been no consistent explanation as to why humans prefer changing their gait from walking to running and from running to walking at increasing and decreasing speeds, respectively. This study examined muscle activation as a possible determinant of these gait transitions. Seven subjects walked and ran on a motor-driven treadmill for 40s at speeds of 55, 70, 85, 100, 115, 130 and 145% of the preferred transition speed. The movements of subjects were videotaped, and surface electromyographic activity was recorded from seven major leg muscles. Resultant moments at the leg joints during the swing phase were calculated. During the swing phase of locomotion at preferred running speeds (115, 130, 145%), swing-related activation of the ankle, knee and hip flexors and peaks of flexion moments were typically lower (P<0.05) during running than during walking. At preferred walking speeds (55, 70, 85%), support-related activation of the ankle and knee extensors was typically lower during stance of walking than during stance of running (P<0.05). These results support the hypothesis that the preferred walk-run transition might be triggered by the increased sense of effort due to the exaggerated swing-related activation of the tibialis anterior, rectus femoris and hamstrings; this increased activation is necessary to meet the higher joint moment demands to move the swing leg during fast walking. The preferred run-walk transition might be similarly triggered by the sense of effort due to the higher support-related activation of the soleus, gastrocnemius and vastii that must generate higher forces during slow running than during walking at the same speed.

Race walking gait and its influence on race walking economy in world-class race walkers.

PubMed

Gomez-Ezeiza, Josu; Torres-Unda, Jon; Tam, Nicholas; Irazusta, Jon; Granados, Cristina; Santos-Concejero, Jordan

2018-03-06

The aim of this study was to determine the relationships between biomechanical parameters of the gait cycle and race walking economy in world-class Olympic race walkers. Twenty-One world-class race walkers possessing the Olympic qualifying standard participated in this study. Participants completed an incremental race walking test starting at 10 km·h -1 , where race walking economy (ml·kg -1 ·km -1 ) and spatiotemporal gait variables were analysed at different speeds. 20-km race walking performance was related to race walking economy, being the fastest race walkers those displaying reduced oxygen cost at a given speed (R = 0.760, p < 0.001). Longer ground contact times, shorter flight times, longer midstance sub-phase and shorter propulsive sub-phase during stance were related to a better race walking economy (moderate effect, p < 0.05). According to the results of this study, the fastest race walkers were more economi cal than the lesser performers. Similarly, shorter flight times are associated with a more efficient race walking economy. Coaches and race walkers should avoid modifying their race walking style by increasing flight times, as it may not only impair economy, but also lead to disqualification.

Walking and child pedestrian injury: a systematic review of built environment correlates of safe walking.

PubMed

Rothman, Linda; Buliung, Ron; Macarthur, Colin; To, Teresa; Howard, Andrew

2014-02-01

The child active transportation literature has focused on walking, with little attention to risk associated with increased traffic exposure. This paper reviews the literature related to built environment correlates of walking and pedestrian injury in children together, to broaden the current conceptualization of walkability to include injury prevention. Two independent searches were conducted focused on walking in children and child pedestrian injury within nine electronic databases until March, 2012. Studies were included which: 1) were quantitative 2) set in motorized countries 3) were either urban or suburban 4) investigated specific built environment risk factors 5) had outcomes of either walking in children and/or child pedestrian roadway collisions (ages 0-12). Built environment features were categorized according to those related to density, land use diversity or roadway design. Results were cross-tabulated to identify how built environment features associate with walking and injury. Fifty walking and 35 child pedestrian injury studies were identified. Only traffic calming and presence of playgrounds/recreation areas were consistently associated with more walking and less pedestrian injury. Several built environment features were associated with more walking, but with increased injury. Many features had inconsistent results or had not been investigated for either outcome. The findings emphasise the importance of incorporating safety into the conversation about creating more walkable cities.

Quantum walks: The first detected passage time problem

NASA Astrophysics Data System (ADS)

Friedman, H.; Kessler, D. A.; Barkai, E.

2017-03-01

Even after decades of research, the problem of first passage time statistics for quantum dynamics remains a challenging topic of fundamental and practical importance. Using a projective measurement approach, with a sampling time τ , we obtain the statistics of first detection events for quantum dynamics on a lattice, with the detector located at the origin. A quantum renewal equation for a first detection wave function, in terms of which the first detection probability can be calculated, is derived. This formula gives the relation between first detection statistics and the solution of the corresponding Schrödinger equation in the absence of measurement. We illustrate our results with tight-binding quantum walk models. We examine a closed system, i.e., a ring, and reveal the intricate influence of the sampling time τ on the statistics of detection, discussing the quantum Zeno effect, half dark states, revivals, and optimal detection. The initial condition modifies the statistics of a quantum walk on a finite ring in surprising ways. In some cases, the average detection time is independent of the sampling time while in others the average exhibits multiple divergences as the sampling time is modified. For an unbounded one-dimensional quantum walk, the probability of first detection decays like (time)(-3 ) with superimposed oscillations, with exceptional behavior when the sampling period τ times the tunneling rate γ is a multiple of π /2 . The amplitude of the power-law decay is suppressed as τ →0 due to the Zeno effect. Our work, an extended version of our previously published paper, predicts rich physical behaviors compared with classical Brownian motion, for which the first passage probability density decays monotonically like (time)-3 /2, as elucidated by Schrödinger in 1915.

Timing resolution and time walk in super low K factor single-photon avalanche diode-measurement and optimization

NASA Astrophysics Data System (ADS)

Fong, Bernicy S.; Davies, Murray; Deschamps, Pierre

2018-01-01

Timing resolution (or timing jitter) and time walk are separate parameters associated with a detector's response time. Studies have been done mostly on the time resolution of various single-photon detectors. As the designer and manufacturer of the ultra-low noise (ƙ-factor) silicon avalanche photodiode the super low K factor (SLiK) single-photon avalanche diode (SPAD), which is used in many single-photon counting applications, we often get inquiries from customers to better understand how this detector behaves under different operating conditions. Hence, here, we will be focusing on the study of these time-related parameters specifically for the SLiK SPAD, as a way to provide the most direct information for users of this detector to help with its use more efficiently and effectively. We will be providing the study data on how these parameters can be affected by temperature (both intrinsic to the detector chip and environmental input based on operating conditions), operating voltage, photon wavelength, as well as light spot size. How these parameters can be optimized and the trade-offs from optimization from the desired performance will be presented?

Developing Point-of-Decision Prompts to Encourage Airport Walking: The Walk to Fly Study.

PubMed

Frederick, Ginny M; Paul, Prabasaj; Bachtel Watson, Kathleen; Dorn, Joan M; Fulton, Janet

2016-04-01

Point-of-decision prompts may be appropriate to promote walking, instead of using a mechanized mode of transport, such as a train, in airports. To our knowledge, no current studies describe the development of messages for prompts in this setting. In-person interviews were conducted with 150 randomly selected airport travelers who rode the train to their departure gate. Travelers reported various reasons for riding the train to their gate. They were asked about messages that would encourage them to walk. Exploratory factor analysis was conducted for reasons for riding the train. Confirmatory factor analysis was conducted for messages to encourage walking to the departure gate. Travelers reported not knowing walking was an option (23.8%), seeing others riding the train (14.4%), and being afraid of getting lost (9.2%) as reasons for riding the train. Many indicated that directional signs and prompts promoting walking as exercise would encourage them to walk instead of riding the train. Some reasons for riding the train in an airport may be modifiable by installing point-of-decision prompts. Providing directional signs to travelers may prompt them to walk to their gate instead of riding the train. Similar prompts may also be considered in other community settings.

Developing Point-of-Decision Prompts to Encourage Airport Walking: The Walk to Fly Study

PubMed Central

Frederick, Ginny M.; Paul, Prabasaj; Watson, Kathleen Bachtel; Dorn, Joan M.; Fulton, Janet

2017-01-01

Background Point-of-decision prompts may be appropriate to promote walking, instead of using a mechanized mode of transport, such as a train, in airports. To our knowledge, no current studies describe the development of messages for prompts in this setting. Methods In-person interviews were conducted with 150 randomly selected airport travelers who rode the train to their departure gate. Travelers reported various reasons for riding the train to their gate. They were asked about messages that would encourage them to walk. Exploratory factor analysis was conducted for reasons for riding the train. Confirmatory factor analysis was conducted for messages to encourage walking to the departure gate. Results Travelers reported not knowing walking was an option (23.8%), seeing others riding the train (14.4%), and being afraid of getting lost (9.2%) as reasons for riding the train. Many indicated that directional signs and prompts promoting walking as exercise would encourage them to walk instead of riding the train. Conclusions Some reasons for riding the train in an airport may be modifiable by installing point-of-decision prompts. Providing directional signs to travelers may prompt them to walk to their gate instead of riding the train. Similar prompts may also be considered in other community settings. PMID:26445371

Assessment of a Solar System Walk

ERIC Educational Resources Information Center

LoPresto, Michael C.; Murrell, Steven R.; Kirchner, Brian

2010-01-01

The idea of sending students and the general public on a walk through a scale model of the solar system in an attempt to instill an appreciation of the relative scales of the sizes of the objects compared to the immense distances between them is certainly not new. A good number of such models exist, including one on the National Mall in…

Slut-Shaming, Girl Power and "Sexualisation": Thinking through the Politics of the International SlutWalks with Teen Girls

ERIC Educational Resources Information Center

Ringrose, Jessica; Renold, Emma

2012-01-01

This viewpoint begins by exploring whether the global phenomenon of the 2011 "SlutWalks" constitutes a feminist politics of re-signification. We then look at some qualitative, focus group data with teen girls who participated in a UK SlutWalk. We suggest girls are not only negotiating a schizoid double pull towards performing knowing…

Knuckle-walking anteater: a convergence test of adaptation for purported knuckle-walking features of African Hominidae.

PubMed

Orr, Caley M

2005-11-01

Appeals to synapomorphic features of the wrist and hand in African apes, early hominins, and modern humans as evidence of knuckle-walking ancestry for the hominin lineage rely on accurate interpretations of those features as adaptations to knuckle-walking locomotion. Because Gorilla, Pan, and Homo share a relatively close common ancestor, the interpretation of such features is confounded somewhat by phylogeny. The study presented here examines the evolution of a similar locomotor regime in New World anteaters (order Xenarthra, family Myrmecophagidae) and uses the terrestrial giant anteater (Myrmecophaga tridactyla) as a convergence test of adaptation for purported knuckle-walking features of the Hominidae. During the stance phase of locomotion, Myrmecophaga transmits loads through flexed digits and a vertical manus, with hyperextension occurring at the metacarpophalangeal joints of the weight-bearing rays. This differs from the locomotion of smaller, arboreal anteaters of outgroup genera Tamandua and Cyclopes that employ extended wrist postures during above-branch quadrupedality. A number of features shared by Myrmecophaga and Pan and Gorilla facilitate load transmission or limit extension, thereby stabilizing the wrist and hand during knuckle-walking, and distinguish these taxa from their respective outgroups. These traits are a distally extended dorsal ridge of the distal radius, proximal expansion of the nonarticular surface of the dorsal capitate, a pronounced articular ridge on the dorsal aspects of the load-bearing metacarpal heads, and metacarpal heads that are wider dorsally than volarly. Only the proximal expansion of the nonarticular area of the dorsal capitate distinguishes knuckle-walkers from digitigrade cercopithecids, but features shared with digitigrade primates might be adaptive to the use of a vertical manus of some sort in the stance phase of terrestrial locomotion. The appearance of capitate nonarticular expansion and the dorsal ridge of the

Complexity in built environment, health, and destination walking: a neighborhood-scale analysis.

PubMed

Carlson, Cynthia; Aytur, Semra; Gardner, Kevin; Rogers, Shannon

2012-04-01

This study investigates the relationships between the built environment, the physical attributes of the neighborhood, and the residents' perceptions of those attributes. It focuses on destination walking and self-reported health, and does so at the neighborhood scale. The built environment, in particular sidewalks, road connectivity, and proximity of local destinations, correlates with destination walking, and similarly destination walking correlates with physical health. It was found, however, that the built environment and health metrics may not be simply, directly correlated but rather may be correlated through a series of feedback loops that may regulate risk in different ways in different contexts. In particular, evidence for a feedback loop between physical health and destination walking is observed, as well as separate feedback loops between destination walking and objective metrics of the built environment, and destination walking and perception of the built environment. These feedback loops affect the ability to observe how the built environment correlates with residents' physical health. Previous studies have investigated pieces of these associations, but are potentially missing the more complex relationships present. This study proposes a conceptual model describing complex feedback relationships between destination walking and public health, with the built environment expected to increase or decrease the strength of the feedback loop. Evidence supporting these feedback relationships is presented.

Land Use, Residential Density, and Walking

PubMed Central

Rodríguez, Daniel A.; Evenson, Kelly R.; Diez Roux, Ana V.; Brines, Shannon J.

2009-01-01

Background The neighborhood environment may play a role in encouraging sedentary patterns, especially for middle-aged and older adults. Purpose Associations between walking and neighborhood population density, retail availability, and land use distribution were examined using data from a cohort of adults aged 45 to 84 years old. Methods Data from a multi-ethnic sample of 5529 adult residents of Baltimore MD, Chicago IL, Forsyth County NC, Los Angeles CA, New York NY, and St. Paul MN, enrolled in the Multi-Ethnic Study of Atherosclerosis in 2000–2002 were linked to secondary land use and population data. Participant reports of access to destinations and stores and objective measures of the percentage of land area in parcels devoted to retail land uses, the population divided by land area in parcels, and the mixture of uses for areas within 200m of each participant's residence were examined. Multinomial logistic regression was used to investigate associations of self-reported and objective neighborhood characteristics with walking. All analyses were conducted in 2008 and 2009. Results After adjustment for individual-level characteristics and neighborhood connectivity, higher density, greater land area devoted to retail uses, and self-reported measures of proximity of destinations and ease of walking to places were each related to walking. In models including all land use measures, population density was positively associated with walking to places and with walking for exercise for more than 90 min/wk both relative to no walking. Availability of retail was associated with walking to places relative to not walking, having a more proportional mix of land uses was associated with walking for exercise for more than 90 min/wk, while self-reported ease of access to places was related to higher levels of exercise walking both relative to not walking. Conclusions Residential density and the presence of retail uses are related to various walking behaviors. Efforts to

Environmental factors influencing older adults’ walking for transportation: a study using walk-along interviews

PubMed Central

2012-01-01

Background Current knowledge on the relationship between the physical environment and walking for transportation among older adults (≥ 65 years) is limited. Qualitative research can provide valuable information and inform further research. However, qualitative studies are scarce and fail to include neighborhood outings necessary to study participants’ experiences and perceptions while interacting with and interpreting the local social and physical environment. The current study sought to uncover the perceived environmental influences on Flemish older adults’ walking for transportation. To get detailed and context-sensitive environmental information, it used walk-along interviews. Methods Purposeful convenience sampling was used to recruit 57 older adults residing in urban or semi-urban areas. Walk-along interviews to and from a destination (e.g. a shop) located within a 15 minutes’ walk from the participants’ home were conducted. Content analysis was performed using NVivo 9 software (QSR International). An inductive approach was used to derive categories and subcategories from the data. Results Data were categorized in the following categories and subcategories: access to facilities (shops & services, public transit, connectivity), walking facilities (sidewalk quality, crossings, legibility, benches), traffic safety (busy traffic, behavior of other road users), familiarity, safety from crime (physical factors, other persons), social contacts, aesthetics (buildings, natural elements, noise & smell, openness, decay) and weather. Conclusions The findings indicate that to promote walking for transportation a neighborhood should provide good access to shops and services, well-maintained walking facilities, aesthetically appealing places, streets with little traffic and places for social interaction. In addition, the neighborhood environment should evoke feelings of familiarity and safety from crime. Future quantitative studies should investigate if (changes

Welfare assessment in broiler farms: transect walks versus individual scoring.

PubMed

Marchewka, J; Watanabe, T T N; Ferrante, V; Estevez, I

2013-10-01

Current scientific approaches to welfare assessment in broilers are based on individual sampling that can be time consuming under field conditions. On the other hand, farmers conduct routine checks based on walks through the house to screen birds' health condition. We adapted the walks through following line transect methodology used in wildlife studies to explore their feasibility as a welfare assessment tool. The aim of this study was to compare broiler welfare assessed by individual sampling and transect walks. We evaluated 6 identically managed flocks. For individual sampling, we collected measures on 150 birds, including weight, breast dirtiness, hock and footpad dermatitis, lameness, and immobility. Transect observations were conducted by slowly walking on randomized paths within each house recording: immobility, lameness, back dirtiness, sickness, agony, and dead. Transect walks allowed detection of small variations (P < 0.003) in the prevalence of most welfare indicators considered with consistency in interobserver reliability (P ≥ 0.05). In addition, assessments across transects were highly consistent (P ≥ 0.05). Individual sampling was also sensitive to differences across houses (P < 0.01) with the exception of immobility (P = 0.783). No differences were found across sampling locations (P ≥ 0.05). However, both methods differed greatly in the frequency of the incidence of the parameters considered. For example, immobility varied from 0.2 ± 0.02% for transect walks to 4 ± 2.3% for individual sampling, whereas lameness varied between 0.8 ± 0.07% and 24.2 ± 4.7% for transect and samplings, respectively. It is possible that the transect approach may have overlooked walking deficiencies because a large number of birds were scored, although if this was the case, the consistency obtained in the scoring across observers and transects would be surprising. Differences may also be related to possibly biased individual sampling procedures, where less mobile

Environmental perceptions and objective walking trail audits inform a community-based participatory research walking intervention

PubMed Central

2012-01-01

Background Given the documented physical activity disparities that exist among low-income minority communities and the increased focused on socio-ecological approaches to address physical inactivity, efforts aimed at understanding the built environment to support physical activity are needed. This community-based participatory research (CBPR) project investigates walking trails perceptions in a high minority southern community and objectively examines walking trails. The primary aim is to explore if perceived and objective audit variables predict meeting recommendations for walking and physical activity, MET/minutes/week of physical activity, and frequency of trail use. Methods A proportional sampling plan was used to survey community residents in this cross-sectional study. Previously validated instruments were pilot tested and appropriately adapted and included the short version of the validated International Physical Activity Questionnaire, trail use, and perceptions of walking trails. Walking trails were assessed using the valid and reliable Path Environmental Audit Tool which assesses four content areas including: design features, amenities, maintenance, and pedestrian safety from traffic. Analyses included Chi-square, one-way ANOVA's, multiple linear regression, and multiple logistic models. Results Numerous (n = 21) high quality walking trails were available. Across trails, there were very few indicators of incivilities and safety features rated relatively high. Among the 372 respondents, trail use significantly predicted meeting recommendations for walking and physical activity, and MET/minutes/week. While controlling for other variables, significant predictors of trail use included proximity to trails, as well as perceptions of walking trail safety, trail amenities, and neighborhood pedestrian safety. Furthermore, while controlling for education, gender, and income; for every one time per week increase in using walking trails, the odds for meeting walking

Treadmill walking in water induces greater respiratory muscle fatigue than treadmill walking on land in healthy young men.

PubMed

Yamashina, Yoshihiro; Yokoyama, Hisayo; Naghavi, Nooshin; Hirasawa, Yoshikazu; Takeda, Ryosuke; Ota, Akemi; Imai, Daiki; Miyagawa, Toshiaki; Okazaki, Kazunobu

2016-05-01

The purpose of the present study was to investigate the effect of walking in water on respiratory muscle fatigue compared with that of walking on land at the same exercise intensity. Ten healthy males participated in 40-min treadmill walking trials on land and in water at an intensity of 60% of peak oxygen consumption. Respiratory function and respiratory muscle strength were evaluated before and after walking trials. Inspiratory muscle strength and forced expiratory volume in 1 s were significantly decreased immediately after walking in water, and expiratory muscle strength was significantly decreased immediately and 5 min after walking in water compared with the baseline. The decreases of inspiratory and expiratory muscle strength were significantly greater compared with that after walking on land. In conclusion, greater inspiratory and expiratory muscle fatigue was induced by walking in water than by walking on land at the same exercise intensity in healthy young men.

Broadband enhanced transmission of acoustic waves through serrated metal gratings

NASA Astrophysics Data System (ADS)

Qi, Dong-Xiang; Fan, Ren-Hao; Deng, Yu-Qiang; Peng, Ru-Wen; Wang, Mu; Jiangnan University Collaboration

In this talk, we present our studies on broadband properties of acoustic waves through metal gratings. We have demonstrated that serrated metal gratings, which introduce gradient coatings, can give rise to broadband transmission enhancement of acoustic waves. Here, we have experimentally and theoretically studied the acoustic transmission properties of metal gratings with or without serrated boundaries. The average transmission is obviously enhanced for serrated metal gratings within a wide frequency range, while the Fabry-Perot resonance is significantly suppressed. An effective medium hypothesis with varying acoustic impedance is proposed to analyze the mechanism, which was verified through comparison with finite-element simulation. The serrated boundary supplies gradient mass distribution and gradient normal acoustic impedance, which could efficiently reduce the boundary reflection. Further, by increasing the region of the serrated boundary, we present a broadband high-transmission grating for wide range of incident angle. Our results may have potential applications to broadband acoustic imaging, acoustic sensing and new acoustic devices. References: [1] Dong-Xiang Qi, Yu-Qiang Deng, Di-Hu Xu, Ren-Hao Fan, Ru-Wen Peng, Ze-Guo Chen, Ming-Hui Lu, X. R. Huang and Mu Wang, Appl. Phys. Lett. 106, 011906 (2015); [2] Dong-Xiang Qi, Ren-Hao Fan, Ru-Wen Peng, Xian-Rong Huang, Ming-Hui Lu, Xu Ni, Qing Hu, and Mu Wang, Applied Physics Letters 101, 061912 (2012).

Equivalence of Szegedy's and coined quantum walks

NASA Astrophysics Data System (ADS)

Wong, Thomas G.

2017-09-01

Szegedy's quantum walk is a quantization of a classical random walk or Markov chain, where the walk occurs on the edges of the bipartite double cover of the original graph. To search, one can simply quantize a Markov chain with absorbing vertices. Recently, Santos proposed two alternative search algorithms that instead utilize the sign-flip oracle in Grover's algorithm rather than absorbing vertices. In this paper, we show that these two algorithms are exactly equivalent to two algorithms involving coined quantum walks, which are walks on the vertices of the original graph with an internal degree of freedom. The first scheme is equivalent to a coined quantum walk with one walk step per query of Grover's oracle, and the second is equivalent to a coined quantum walk with two walk steps per query of Grover's oracle. These equivalences lie outside the previously known equivalence of Szegedy's quantum walk with absorbing vertices and the coined quantum walk with the negative identity operator as the coin for marked vertices, whose precise relationships we also investigate.

First Steps into Language? Examining the Specific Longitudinal Relations between Walking, Exploration and Linguistic Skills

PubMed Central

Oudgenoeg-Paz, Ora; Volman, M(Chiel). J. M.; Leseman, Paul P. M.

2016-01-01

Recent empirical evidence demonstrates relationships between motor and language development that are partially mediated by exploration. This is in line with the embodied cognition approach to development that views language as grounded in real-life sensorimotor interactions with the environment. This view implies that the relations between motor and linguistic skills should be specific. Moreover, as motor development initially changes the possibilities children have to explore the environment, initial relations between motor and linguistic skills should become weaker over time. Empirical evidence pertaining to the duration and specificity of these relations is still lacking. The current study investigated longitudinal relations between attainment of walking and the development of several linguistic skills, and tested whether exploration through self-locomotion mediated these relations. Linguistic skills were measured at age 43 months, which is later than the age used in previous studies. Three hypotheses were tested: (1) the relations between walking and language found at younger ages will decrease over time (2) exploration through self-locomotion will remain an important predictor of spatial language (3) no relation will be found between walking, exploration and the use of grammatical and lexical categories and between exploration and general vocabulary. Thirty-one Dutch children took part in a longitudinal study. Parents reported about age of attainment of walking. Exploration through self-locomotion was measured using observations of play with a standard set of toys at age 20 months. Receptive vocabulary, spatial language and use of grammatical and lexical categories were measured at age 43 months using (standard) tests. Results reveal that age of walking does not directly predict spatial language at age 43 months. Exploration through self-locomotion does significantly and completely mediate the indirect effect of age of walking on spatial language. Moreover

First Steps into Language? Examining the Specific Longitudinal Relations between Walking, Exploration and Linguistic Skills.

PubMed

Oudgenoeg-Paz, Ora; Volman, M Chiel J M; Leseman, Paul P M

2016-01-01

Recent empirical evidence demonstrates relationships between motor and language development that are partially mediated by exploration. This is in line with the embodied cognition approach to development that views language as grounded in real-life sensorimotor interactions with the environment. This view implies that the relations between motor and linguistic skills should be specific. Moreover, as motor development initially changes the possibilities children have to explore the environment, initial relations between motor and linguistic skills should become weaker over time. Empirical evidence pertaining to the duration and specificity of these relations is still lacking. The current study investigated longitudinal relations between attainment of walking and the development of several linguistic skills, and tested whether exploration through self-locomotion mediated these relations. Linguistic skills were measured at age 43 months, which is later than the age used in previous studies. Three hypotheses were tested: (1) the relations between walking and language found at younger ages will decrease over time (2) exploration through self-locomotion will remain an important predictor of spatial language (3) no relation will be found between walking, exploration and the use of grammatical and lexical categories and between exploration and general vocabulary. Thirty-one Dutch children took part in a longitudinal study. Parents reported about age of attainment of walking. Exploration through self-locomotion was measured using observations of play with a standard set of toys at age 20 months. Receptive vocabulary, spatial language and use of grammatical and lexical categories were measured at age 43 months using (standard) tests. Results reveal that age of walking does not directly predict spatial language at age 43 months. Exploration through self-locomotion does significantly and completely mediate the indirect effect of age of walking on spatial language. Moreover

Novel high-resolution VGA QWIP detector

NASA Astrophysics Data System (ADS)

Kataria, H.; Asplund, C.; Lindberg, A.; Smuk, S.; Alverbro, J.; Evans, D.; Sehlin, S.; Becanovic, S.; Tinghag, P.; Höglund, L.; Sjöström, F.; Costard, E.

2017-02-01

Continuing with its legacy of producing high performance infrared detectors, IRnova introduces its high resolution LWIR IDDCA (Integrated Detector Dewar Cooler assembly) based on QWIP (quantum well infrared photodetector) technology. The Focal Plane Array (FPA) has 640×512 pixels, with small (15μm) pixel pitch, and is based on the FLIRIndigo ISC0403 Readout Integrated Circuit (ROIC). The QWIP epitaxial structures are grown by metal-organic vapor phase epitaxy (MOVPE) at IRnova. Detector stability and response uniformity inherent to III/V based material will be demonstrated in terms of high performing detectors. Results showing low NETD at high frame rate will be presented. This makes it one of the first 15μm pitch QWIP based LWIR IDDCA commercially available on the market. High operability and stability of our other QWIP based products will also be shared.

Method of fabricating multiwavelength infrared focal plane array detector

NASA Technical Reports Server (NTRS)

Forrest, Stephen R. (Inventor); Olsen, Gregory H. (Inventor); Kim, Dong-Su (Inventor); Lange, Michael J. (Inventor)

1996-01-01

A multiwavelength local plane array infrared detector is included on a common substrate having formed on its top face a plurality of In.sub.x Ga.sub.1-x As (x.ltoreq.0.53) absorption layers, between each pair of which a plurality of InAs.sub.y P.sub.1-y (y.ltoreq.1) buffer layers are formed having substantially increasing lattice parameters, respectively, relative to said substrate, for preventing lattice mismatch dislocations from propagating through successive ones of the absorption layers of decreasing bandgap relative to said substrate, whereby a plurality of detectors for detecting different wavelengths of light for a given pixel are provided by removing material above given areas of successive ones of the absorption layers, which areas are doped to form a pn junction with the surrounding unexposed portions of associated absorption layers, respectively, with metal contacts being formed on a portion of each of the exposed areas, and on the bottom of the substrate for facilitating electrical connections thereto.

Association between neighborhood walkability and GPS-measured walking, bicycling and vehicle time in adolescents.

PubMed

Carlson, Jordan A; Saelens, Brian E; Kerr, Jacqueline; Schipperijn, Jasper; Conway, Terry L; Frank, Lawrence D; Chapman, Jim E; Glanz, Karen; Cain, Kelli L; Sallis, James F

2015-03-01

To investigate relations of walking, bicycling and vehicle time to neighborhood walkability and total physical activity in youth. Participants (N=690) were from 380 census block groups of high/low walkability and income in two US regions. Home neighborhood residential density, intersection density, retail density, entertainment density and walkability were derived using GIS. Minutes/day of walking, bicycling and vehicle time were derived from processing algorithms applied to GPS. Accelerometers estimated total daily moderate-to-vigorous physical activity (MVPA). Models were adjusted for nesting of days (N=2987) within participants within block groups. Walking occurred on 33%, active travel on 43%, and vehicle time on 91% of the days observed. Intersection density and neighborhood walkability were positively related to walking and bicycling and negatively related to vehicle time. Residential density was positively related to walking. Increasing walking in youth could be effective in increasing total physical activity. Built environment findings suggest potential for increasing walking in youth through improving neighborhood walkability. Copyright © 2014 Elsevier Ltd. All rights reserved.

Walking on sunshine: scoping review of the evidence for walking and mental health.

PubMed

Kelly, Paul; Williamson, Chloë; Niven, Ailsa G; Hunter, Ruth; Mutrie, Nanette; Richards, Justin

2018-06-01

Walking has well-established positive relationships with, and effects on, physical health. In contrast, while poor mental health contributes substantially to global health burden, an overview of the benefits from walking has not previously been published. We aimed to scope the literature and present what is known, and highlight what is not known, about walking and mental health. Design: Scoping review. Ovid (Medline), ProQuest, Web of Science.Screening and reporting: 13 014 records were identified and screened by a team of researchers. Included full texts were analysed and reported according to mental health outcome. For the 8 mental health outcomes (identified a priori), there were a total of 5 systematic reviews and 50 individual papers included. Depression had the most evidence and existing systematic reviews were reported. Evidence for anxiety, psychological stress, psychological well-being, subjective well-being and social isolation and loneliness varied in volume and effectiveness, but no harmful effects were identified. There were no studies for walking and resilience. The setting and context of walking seems to be important variables. The evidence base that suggests walking benefits mental health is growing, but remains fragmented and incomplete for some important outcomes. Policy and national guidelines should promote the known mental health benefits of increased walking and future research should directly address the gaps we have identified. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

A field-shaping multi-well avalanche detector for direct conversion amorphous selenium

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

Goldan, A. H.; Zhao, W.

2013-01-15

Purpose: A practical detector structure is proposed to achieve stable avalanche multiplication gain in direct-conversion amorphous selenium radiation detectors. Methods: The detector structure is referred to as a field-shaping multi-well avalanche detector. Stable avalanche multiplication gain is achieved by eliminating field hot spots using high-density avalanche wells with insulated walls and field-shaping inside each well. Results: The authors demonstrate the impact of high-density insulated wells and field-shaping to eliminate the formation of both field hot spots in the avalanche region and high fields at the metal-semiconductor interface. Results show a semi-Gaussian field distribution inside each well using the field-shaping electrodes,more » and the electric field at the metal-semiconductor interface can be one order-of-magnitude lower than the peak value where avalanche occurs. Conclusions: This is the first attempt to design a practical direct-conversion amorphous selenium detector with avalanche gain.« less

Can psychology walk the walk of open science?

PubMed

Hesse, Bradford W

2018-01-01

An "open science movement" is gaining traction across many disciplines within the research enterprise but is also precipitating consternation among those who worry that too much disruption may be hampering professional productivity. Despite this disruption, proponents of open data collaboration have argued that some of the biggest problems of the 21st century need to be solved with the help of many people and that data sharing will be the necessary engine to make that happen. In the United States, a national strategic plan for data sharing encouraged the federally funded scientific agencies to (a) publish open data for community use in discoverable, machine-readable, and useful ways; (b) work with public and civil society organizations to set priorities for data to be shared; (c) support innovation and feedback on open data solutions; and (d) continue efforts to release and enhance high-priority data sets funded by taxpayer dollars. One of the more visible open data projects in the psychological sciences is the presidentially announced "Brain Research Through Advancing Innovative Neurotechnologies" (BRAIN) initiative. Lessons learned from initiatives such as these are instructive both from the perspective of open science within psychology and from the perspective of understanding the psychology of open science. Recommendations for creating better pathways to "walk the walk" in open science include (a) nurturing innovation and agile learning, (b) thinking outside the paradigm, (c) creating simplicity from complexity, and (d) participating in continuous learning evidence platforms. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Stakeholder perceptions of a nurse led walk-in centre.

PubMed

Parker, Rhian M; Desborough, Jane L; Forrest, Laura E

2012-11-05

As many countries face primary care medical workforce shortages and find it difficult to provide timely and affordable care they seek to find new ways of delivering first point of contact health care through developing new service models. In common with other areas of rural and regional Australia, the Australian Capital Territory (ACT) is currently experiencing a general practitioner (GP) workforce shortage which impacts significantly on the ability of patients to access GP led primary care services. The introduction of a nurse led primary care Walk-in Centre in the ACT aimed to fulfill an unmet health care need in the community and meet projected demand for health care services as well as relieve pressure on the hospital system. Stakeholders have the potential to influence health service planning and policy, to advise on the potential of services to meet population health needs and to assess how acceptable health service innovation is to key stakeholder groups. This study aimed to ascertain the views of key stakeholders about the Walk-in Centre. Stakeholders were purposively selected through the identification of individuals and organisations which had organisational or professional contact with the Walk-in Centre. Semi structured interviews around key themes were conducted with seventeen stakeholders. Stakeholders were generally supportive of the Walk-in Centre but identified key areas which they considered needed to be addressed. These included the service's systems, full utilisation of the nurse practitioner role and adequate education and training. It was also suggested that a doctor could be available to the Centre as a source of referral for patients who fall outside the nurses' scope of practice. The location of the Centre was seen to impact on patient flows to the Emergency Department. Nurse led Walk-in Centres are one response to addressing primary health care medical workforce shortages. Whilst some stakeholders have reservations about the model others

The Relationship between U.S. Teachers' Attitudes and Frequency of Principals' Walk-Throughs

ERIC Educational Resources Information Center

Mounts, Samia Sayegh

2009-01-01

Peters and Waterman (1982) viewed management by walking around (MBWA) excellence in leadership. Administrators in the education community face many challenges stemming from not spending enough time in classrooms to gain understanding and insight into what goes on in the classroom. The intent of the present descriptive, cross-sectional study was to…

Relationship of plasma nonesterified fatty acids and walking activity in postpartum dairy cows.

PubMed

Adewuyi, A A; Roelofs, J B; Gruys, E; Toussaint, M J M; van Eerdenburg, F J C M

2006-08-01

To survive and produce milk, postpartum dairy cows use their reserves through lipolysis. If the negative energy balance is severe, nonesterified fatty acids (NEFA) are formed that can impair several physiological processes. A pilot study suggested that increased walking activity after calving may be related to a reduced serum concentration of NEFA. The objective of this study was to determine the relationship between plasma concentrations of NEFA and walking activity in dairy cattle during the postpartum period. Data were collected from 33 multiparous Holstein-Friesian dairy cows. Walking activities were quantified using pedometry, and blood samples were collected for determination of NEFA. Results of this study indicated that a negative relationship existed between walking activity and plasma NEFA concentrations in postpartum dairy cows.

Walking in circles: a modelling approach

PubMed Central

Maus, Horst-Moritz; Seyfarth, Andre

2014-01-01

Blindfolded or disoriented people have the tendency to walk in circles rather than on a straight line even if they wanted to. Here, we use a minimalistic walking model to examine this phenomenon. The bipedal spring-loaded inverted pendulum exhibits asymptotically stable gaits with centre of mass (CoM) dynamics and ground reaction forces similar to human walking in the sagittal plane. We extend this model into three dimensions, and show that stable walking patterns persist if the leg is aligned with respect to the body (here: CoM velocity) instead of a world reference frame. Further, we demonstrate that asymmetric leg configurations, which are common in humans, will typically lead to walking in circles. The diameter of these circles depends strongly on parameter configuration, but is in line with empirical data from human walkers. Simulation results suggest that walking radius and especially direction of rotation are highly dependent on leg configuration and walking velocity, which explains inconsistent veering behaviour in repeated trials in human data. Finally, we discuss the relation between findings in the model and implications for human walking. PMID:25056215

Irreconcilable difference between quantum walks and adiabatic quantum computing

NASA Astrophysics Data System (ADS)

Wong, Thomas G.; Meyer, David A.

2016-06-01

Continuous-time quantum walks and adiabatic quantum evolution are two general techniques for quantum computing, both of which are described by Hamiltonians that govern their evolutions by Schrödinger's equation. In the former, the Hamiltonian is fixed, while in the latter, the Hamiltonian varies with time. As a result, their formulations of Grover's algorithm evolve differently through Hilbert space. We show that this difference is fundamental; they cannot be made to evolve along each other's path without introducing structure more powerful than the standard oracle for unstructured search. For an adiabatic quantum evolution to evolve like the quantum walk search algorithm, it must interpolate between three fixed Hamiltonians, one of which is complex and introduces structure that is stronger than the oracle for unstructured search. Conversely, for a quantum walk to evolve along the path of the adiabatic search algorithm, it must be a chiral quantum walk on a weighted, directed star graph with structure that is also stronger than the oracle for unstructured search. Thus, the two techniques, although similar in being described by Hamiltonians that govern their evolution, compute by fundamentally irreconcilable means.

What Is Walking Pneumonia?

MedlinePlus

... pneumonia: What does it mean? What is walking pneumonia? How is it different from regular pneumonia? Answers from Eric J. Olson, M.D. Walking pneumonia is an informal term for pneumonia that isn' ...

Evaluation of the walk-through inflatable colon as a colorectal cancer education tool: results from a pre and post research design.

PubMed

Sanchez, Janeth I; Palacios, Rebecca; Cole, Adrianna; O'Connell, Mary A

2014-08-28

Colorectal cancer (CRC) is a disease that can be prevented through early detection. Through the use of effective educational tools, individuals can become better informed about CRC and understand the importance of screening and early detection. The walk through Inflatable Colon is an innovative educational resource developed to engage and educate communities on CRC and the importance of receiving screening at the appropriate ages. The Inflatable Colon Assessment Survey (ICAS) assessed knowledge and behavioral intentions to obtain screening and promote CRC awareness. New Mexico State University faculty, staff, and students completed a consent form, took the pre-ICAS, toured the Inflatable Colon, and completed the post-ICAS. The majority of participants (92%) were young adults, mostly college students, under the age of 30 yrs. Overall, participants demonstrated increases in CRC knowledge and awareness after touring the inflatable colon (p-values < 0.001). Interestingly, both males and Hispanics had lower CRC awareness at pre-test, but exhibited maximum awareness gains equal to that of females and non Hispanic Whites after touring the IC. Behavioral intentions to obtain CRC screening in the future and to promote CRC awareness also increased (p-value < 0.001). Gender differences in behavioral intentions to act as advocators for CRC education were found (p < 0.05), with females being more likely to educate others about CRC than males. Educational efforts conducted in early adulthood may serve to promote healthier lifestyles (e.g., physical activity, healthy nutrition, screening). These educated young adults may also serve to disseminate CRC information to high-risk friends and relatives. The walk through Inflatable Colon can increase CRC knowledge and intentions to get screened among a young and diverse population.

Social and environmental predictors of walking among older adults.

PubMed

Ory, Marcia G; Towne, Samuel D; Won, Jaewoong; Forjuoh, Samuel N; Lee, Chanam

2016-08-23

Regular physical activity (PA) is a major factor in maintaining health in aging populations. This study examines the influences of sociodemographic, health, and environmental characteristics on older adults' walking behaviors, and the role physicians can play in promoting physical activity. Online and paper surveys (n = 272) were distributed to community-dwelling older (age ≥ 60) adults from a large integrated healthcare system in two counties in Central Texas. Descriptive statistics were utilized to characterize participant's walking behaviors and places. Multivariate logistic regression was employed to predict being: 1) a frequent walker (i.e., walking at least three times a week); and 2) meeting the Centers for Disease Control and Prevention (CDC) PA recommendation through walking (i.e., walking ≥150 min per week), while considering sociodemographic, health, and environmental factors. Individuals had a median age of 69 years, were of both genders (50.37 % female), and were primarily non-Hispanic White (84.87 %). While the majority (59.55 %) walked at least three times a week, only 27.86 % walked ≥150 min a week. Factors associated with a lower likelihood of being frequent walkers included experiencing poor mental health in the past month (OR = 0.345, 95 % CI = 0.185-0.645) and residing in areas with low or moderate (versus high) perceived neighborhood cohesion (OR = 0.471, 95 % CI = 0.228-0.974), while those in Census Tracts reflecting populations with a lower median age were more likely to report frequent walking behavior (OR = 1.799, 95 % CI = 1.034-3.131). Factors associated with a lower likelihood of meeting the CDC PA recommendation included being 60-69 years (versus 70 years or older) (OR = 0.538, 95 % CI = 0.290-0.997), experiencing poor mental health in the past month (OR = 0.432, 95 % CI = 0.198-0.944), and lacking social support for walking (OR = 0.383, 95 % CI = 0

Consumer preference in ranking walking function utilizing the walking index for spinal cord injury II.

PubMed

Patrick, M; Ditunno, P; Ditunno, J F; Marino, R J; Scivoletto, G; Lam, T; Loffree, J; Tamburella, F; Leiby, B

2011-12-01

Blinded rank ordering. To determine consumer preference in walking function utilizing the walking Index for spinal cord injury II (WISCI II) in individuals with spinal cord injury (SCI)from the Canada, the Italy and the United States of America. In all, 42 consumers with incomplete SCI (25 cervical, 12 thoracic, 5 lumbar) from Canada (12/42), Italy (14/42) and the United States of America (16/42) ranked the 20 levels of the WISCI II scale by their individual preference for walking. Subjects were blinded to the original ranking of the WISCI II scale by clinical scientists. Photographs of each WISCI II level used in a previous pilot study were randomly shuffled and rank ordered. Percentile, conjoint/cluster and graphic analyses were performed. All three analyses illustrated consumer ranking followed a bimodal distribution. Ranking for two levels with physical assistance and two levels with a walker were bimodal with a difference of five to six ranks between consumer subgroups (quartile analysis). The larger cluster (N=20) showed preference for walking with assistance over the smaller cluster (N=12), whose preference was walking without assistance and more devices. In all, 64% (27/42) of consumers ranked WISCI II level with no devices or braces and 1 person assistance higher than multiple levels of the WISCI II requiring no assistance. These results were unexpected, as the hypothesis was that consumers would rank independent walking higher than walking with assistance. Consumer preference for walking function should be considered in addition to objective measures in designing SCI trials that use significant improvement in walking function as an outcome measure.

Screening for physical inactivity among adults: the value of distance walked in the six-minute walk test. A cross-sectional diagnostic study.

PubMed

Sperandio, Evandro Fornias; Arantes, Rodolfo Leite; da Silva, Rodrigo Pereira; Matheus, Agatha Caveda; Lauria, Vinícius Tonon; Bianchim, Mayara Silveira; Romiti, Marcello; Gagliardi, Antônio Ricardo de Toledo; Dourado, Victor Zuniga

2016-01-01

Accelerometry provides objective measurement of physical activity levels, but is unfeasible in clinical practice. Thus, we aimed to identify physical fitness tests capable of predicting physical inactivity among adults. Diagnostic test study developed at a university laboratory and a diagnostic clinic. 188 asymptomatic subjects underwent assessment of physical activity levels through accelerometry, ergospirometry on treadmill, body composition from bioelectrical impedance, isokinetic muscle function, postural balance on a force platform and six-minute walk test. We conducted descriptive analysis and multiple logistic regression including age, sex, oxygen uptake, body fat, center of pressure, quadriceps peak torque, distance covered in six-minute walk test and steps/day in the model, as predictors of physical inactivity. We also determined sensitivity (S), specificity (Sp) and area under the curve of the main predictors by means of receiver operating characteristic curves. The prevalence of physical inactivity was 14%. The mean number of steps/day (≤ 5357) was the best predictor of physical inactivity (S = 99%; Sp = 82%). The best physical fitness test was a distance in the six-minute walk test and ≤ 96% of predicted values (S = 70%; Sp = 80%). Body fat > 25% was also significant (S = 83%; Sp = 51%). After logistic regression, steps/day and distance in the six-minute walk test remained predictors of physical inactivity. The six-minute walk test should be included in epidemiological studies as a simple and cheap tool for screening for physical inactivity.

10 CFR 431.302 - Definitions concerning walk-in coolers and walk-in freezers.

Code of Federal Regulations, 2010 CFR

2010-01-01

... FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT Walk-in Coolers and Walk-in Freezers § 431.302...; however the terms do not include products designed and marketed exclusively for medical, scientific, or...

Optimal speeds for walking and running, and walking on a moving walkway.

PubMed

Srinivasan, Manoj

2009-06-01

Many aspects of steady human locomotion are thought to be constrained by a tendency to minimize the expenditure of metabolic cost. This paper has three parts related to the theme of energetic optimality: (1) a brief review of energetic optimality in legged locomotion, (2) an examination of the notion of optimal locomotion speed, and (3) an analysis of walking on moving walkways, such as those found in some airports. First, I describe two possible connotations of the term "optimal locomotion speed:" that which minimizes the total metabolic cost per unit distance and that which minimizes the net cost per unit distance (total minus resting cost). Minimizing the total cost per distance gives the maximum range speed and is a much better predictor of the speeds at which people and horses prefer to walk naturally. Minimizing the net cost per distance is equivalent to minimizing the total daily energy intake given an idealized modern lifestyle that requires one to walk a given distance every day--but it is not a good predictor of animals' walking speeds. Next, I critique the notion that there is no energy-optimal speed for running, making use of some recent experiments and a review of past literature. Finally, I consider the problem of predicting the speeds at which people walk on moving walkways--such as those found in some airports. I present two substantially different theories to make predictions. The first theory, minimizing total energy per distance, predicts that for a range of low walkway speeds, the optimal absolute speed of travel will be greater--but the speed relative to the walkway smaller--than the optimal walking speed on stationary ground. At higher walkway speeds, this theory predicts that the person will stand still. The second theory is based on the assumption that the human optimally reconciles the sensory conflict between the forward speed that the eye sees and the walking speed that the legs feel and tries to equate the best estimate of the forward

Cognitive function and walking velocity in people with dementia; a comparison of backward and forward walking.

PubMed

Johansson, Hanna; Lundin-Olsson, Lillemor; Littbrand, Håkan; Gustafson, Yngve; Rosendahl, Erik; Toots, Annika

2017-10-01

How forward and backward walking, both central to everyday life, relate to cognition are relatively unexplored in people with dementia. This study aimed to investigate if forward and backward walking velocity respectively, associated with global cognition and executive function in people with dementia, and whether the association differed according to walking aid use or dementia type. Using a cross-sectional design, 161 participants (77% women), a mean Mini-Mental State Examination (MMSE) score of 15, and mean age of 85.5years and living in nursing homes were included. Self-paced forward walking (FW) and backward walking (BW) velocity over 2.4m was measured. Global cognitive outcome measurements included MMSE and Alzheimer Disease Assessment Scale - Cognitive subscale (ADAS-Cog). Executive function was measured using Verbal Fluency (VF). In comprehensively adjusted multivariate linear regression analyses, FW was independently associated with VF (p=0.001), but not MMSE (p=0.126) or ADAS-Cog (p=0.818). BW was independently associated with VF (p=0.043) and MMSE (p=0.022), but not ADAS-Cog (p=0.519). Interaction analyses showed that the association between BW velocity and executive function were stronger in participants who walked without a walking aid. No associations differed according to dementia type. In conclusion, executive function appears important to walking velocity, both forward and backward, in people with dementia with mild to moderately severe cognitive impairment. Global cognitive function was associated with backward walking only, perhaps due to it being more challenging. The association between BW velocity and executive function differed according to use of walking aids, which appeared to attenuate the association. Copyright © 2017 Elsevier B.V. All rights reserved.

Investigating walking environments in and around assisted living facilities: a facility visit study.

PubMed

Lu, Zhipeng

2010-01-01

This study explores assisted living residents' walking behaviors, locations where residents prefer to walk, and walking environments in and around assisted living facilities. Regular walking is beneficial to older adults' physical and psychological health. Yet frail older residents in assisted living are usually too sedentary to achieve these benefits. The physical environment plays an important role in promoting physical activity. However, there is little research exploring this relationship in assisted living settings. The researcher visited 34 assisted living facilities in a major Texas city. Methods included walk-through observation with the Assisted Living Facility Walking Environment Checklist, and interviews with administrators by open- and close-ended questions. The data from 26 facilities were analyzed using descriptive statistics (for quantitative data) and content analysis (for qualitative data). The results indicate that (a) residents were walking both indoors and outdoors for exercise or other purposes (e.g., going to destinations); (b) assisted living facility planning and design details-such as neighborhood sidewalk conditions, facility site selection, availability of seating, walking path configuration (e.g., looped/nonlooped path), amount of shading along the path, presence of handrails, existence of signage, etc.-may influence residents' walking behaviors; and (c) current assisted living facilities need improvement in all aspects to make their environments more walkable for residents. Findings of the study provide recommendations for assisted living facilities to improve the walkability of environments and to create environmental interventions to promote regular walking among their residents. This study also implies several directions for future research.

Walking on four limbs: A systematic review of Nordic Walking in Parkinson disease.

PubMed

Bombieri, Federica; Schena, Federico; Pellegrini, Barbara; Barone, Paolo; Tinazzi, Michele; Erro, Roberto

2017-05-01

Nordic Walking is a relatively high intensity activity that is becoming increasingly popular. It involves marching using poles adapted from cross-country skiing poles in order to activate upper body muscles that would not be used during normal walking. Several studies have been performed using this technique in Parkinson disease patients with contradictory results. Thus, we reviewed here all studies using this technique in Parkinson disease patients and further performed a meta-analysis of RCTs where Nordic Walking was evaluated against standard medical care or other types of physical exercise. Nine studies including four RCTs were reviewed for a total of 127 patients who were assigned to the Nordic Walking program. The majority of studies reported beneficial effects of Nordic Walking on either motor or non-motor variables, but many limitations were observed that hamper drawing definitive conclusions and it is largely unclear whether the benefits persist over time. It would appear that little baseline disability is the strongest predictor of response. The meta-analysis of the 4 RCTs yielded a statistically significant reduction of the UPDRS-3 score, but its value of less than 1 point does not appear to be clinically meaningful. Well-designed, large RCTs should be performed both against standard medical care and other types of physical exercise to definitively address whether Nordic Walking can be beneficial in PD. Copyright © 2017. Published by Elsevier Ltd.

Toe Walking in Children

MedlinePlus

... walking sometimes can result from certain conditions, including cerebral palsy, muscular dystrophy and autism spectrum disorder. Symptoms Toe ... can prevent the heel from touching the ground. Cerebral palsy. Toe walking can be caused by a disorder ...

"Four legs instead of two"--perspectives on a Nordic walking-based walking programme among people with arthritis.

PubMed

O'Donovan, Rhona; Kennedy, Norelee

2015-01-01

Nordic Walking (NW) is growing in popularity among people with arthritis. The aim of this study was to explore the perspectives of participants with arthritis on a NW-based walking programme including factors contributing to sustained participation in the programme. Three semi-structured focus groups were conducted with a total of 27 participants with various types of arthritis. The groups consisted of participants who completed a NW-based walking programme in the previous 4 years. Only participants who had sustained involvement in the walking group were included. Groups were audio-recorded, transcribed verbatim and thematic analysis was performed. Participants reported that the walking programme offered numerous benefits. Two distinct themes emerged: (1) "four legs instead of two legs" and (2) "a support group". Theme 1 incorporates the physical, psychological and educational benefits that stem from involvement in a walking group while Theme 2 incorporates the benefits of social support in group-based activity. Several benefits of a NW-based walking programme from the perspectives of individuals with arthritis who engage in group-based walking programmes were identified. The benefits may encourage sustained participation and justify the promotion of NW as an intervention for people with arthritis. Considering how to sustain exercise participation is important to ensure continued benefits from physical activity participation. A community-based Nordic walking-based walking programme for people with arthritis improved exercise knowledge and confidence to exercise. Group exercise is valuable in providing support and motivation to continue exercising.

The CHOICE study: a "taste-test" of utilitarian vs. leisure walking among older adults.

PubMed

Hekler, Eric B; Castro, Cynthia M; Buman, Matthew P; King, Abby C

2012-01-01

Utilitarian walking (e.g., walking for transport) and leisure walking (e.g., walking for health/recreation) are encouraged to promote health, yet few studies have explored specific preferences for these two forms of physical activity or factors that impact such preferences. A quasi-experimental crossover design was used to evaluate how training underactive midlife and older adults in each type of walking impacted total steps taken and how it was linked to their subsequent choice of walking types. Participants (N = 16) were midlife and older adults (M age = 64 ± 8 years) who were mostly women (81%) and white (75%). To control for order effects, participants were randomized to instruction in either utilitarian or leisure walking for 2 weeks and then the other type for 2 weeks. Participants then entered a 2-week "free choice" phase in which they chose any mixture of the walking types. Outcome variables included walking via OMRON pedometer and the ratio of utilitarian versus leisure walking during the free-choice phase. Participants completed surveys about their neighborhood (NEWS) and daily travel to multiple locations. Instruction in leisure-only, utilitarian-only, and a freely chosen mixture of the two each resulted in significant increases in steps taken relative to baseline (ps < 0.05). Having to go to multiple locations daily and traveling greater distances to locations were associated with engagement in more utilitarian walking. In contrast, good walking paths, neighborhood aesthetics, easy access to exercise facilities, and perceiving easier access to neighborhood services were associated with more leisure walking. Results from this pilot study suggest that midlife and older adults may most easily meet guidelines through either leisure only or a mixture of leisure and utilitarian walking, and tailored suggestions based on the person's neighborhood may be useful.

Adaptation of the walking pattern to uphill walking in normal and spinal-cord injured subjects.

PubMed

Leroux, A; Fung, J; Barbeau, H

1999-06-01

Lower-limb movements and muscle-activity patterns were assessed from seven normal and seven ambulatory subjects with incomplete spinal-cord injury (SCI) during level and uphill treadmill walking (5, 10 and 15 degrees). Increasing the treadmill grade from 0 degrees to 15 degrees induced an increasingly flexed posture of the hip, knee and ankle during initial contact in all normal subjects, resulting in a larger excursion throughout stance. This adaptation process actually began in mid-swing with a graded increase in hip flexion and ankle dorsiflexion as well as a gradual decrease in knee extension. In SCI subjects, a similar trend was found at the hip joint for both swing and stance phases, whereas the knee angle showed very limited changes and the ankle angle showed large variations with grade throughout the walking cycle. A distinct coordination pattern between the hip and knee was observed in normal subjects, but not in SCI subjects during level walking. The same coordination pattern was preserved in all normal subjects and in five of seven SCI subjects during uphill walking. The duration of electromyographic (EMG) activity of thigh muscles was progressively increased during uphill walking, whereas no significant changes occurred in leg muscles. In SCI subjects, EMG durations of both thigh and leg muscles, which were already active throughout stance during level walking, were not significantly affected by uphill walking. The peak amplitude of EMG activity of the vastus lateralis, medial hamstrings, soleus, medial gastrocnemius and tibialis anterior was progressively increased during uphill walking in normal subjects. In SCI subjects, the peak amplitude of EMG activity of the medial hamstrings was adapted in a similar fashion, whereas the vastus lateralis, soleus and medial gastrocnemius showed very limited adaptation during uphill walking. We conclude that SCI subjects can adapt to uphill treadmill walking within certain limits, but they use different strategies

Partnering with libraries to promote walking among community-dwelling adults: a Kingston gets active pilot pedometer-lending project.

PubMed

Ryder, Holly H; Faloon, Kathryn J; Lévesque, Lucie; McDonald, Deanna

2009-10-01

Most adults do not walk enough to obtain health benefits. Pedometers have been successfully utilized to motivate and increase walking. Given that libraries are a place where community members seek health resources, they are a logical setting for increasing community accessibility to pedometers. The purpose was to examine the feasibility of lending pedometers to library patrons to increase walking. In five Canadian public libraries, 90 pedometers were made available for 6 months. A total of 41 library patrons (33 women, 8 men, age range 18 to 65 or older) completed a survey about their walking patterns and pedometer use. More than 330 loans were made. Chisquare analysis found significant associations between walking and motivation to walk more (p < .05), walking and goal setting (p < .05), and motivation to walk more and setting a walking goal (p < .001). Results provide preliminary evidence that lending pedometers through local libraries is an effective, low-cost approach to enhance walking in community members.

Obesity history as a predictor of walking limitation at old age.

PubMed

Stenholm, Sari; Rantanen, Taina; Alanen, Erkki; Reunanen, Antti; Sainio, Päivi; Koskinen, Seppo

2007-04-01

To study whether walking limitation at old age is determined by obesity history. In a retrospective longitudinal study based on a representative sample of the Finnish population of 55 years and older (2055 women and 1337 men), maximal walking speed, body mass, and body height were measured in a health examination. Walking limitation was defined as walking speed<1.2 m/s or difficulty in walking 0.5 km. Recalled height at 20 years of age and recalled weight at 20, 30, 40, and 50 years of age were recorded. Subjects who had been obese at the age of 30, 40, or 50 years had almost a 4-fold higher risk of walking limitation compared to non-obese. Obesity duration increased the age- and gender-adjusted risk of walking limitation among those who had been obese since the age of 50 (odds ratio, 4.33; 95% confidence interval, 2.59 to 7.23, n=114), among the obese since the age of 40 [6.01 (2.55 to 14.14), n=39], and among the obese since the age of 30 [8.97 (3.06 to 26.29), n=14]. The risk remained elevated even among those who had previously been obese but lost weight during their midlife or late adulthood [3.15 (1.63 to 6.11), n=71]. Early onset of obesity and obesity duration increased the risk of walking limitation, and the effect was only partially mediated through current BMI and higher risk of obesity-related diseases. Preventing excess weight gain throughout one's life course is an important goal in order to promote good health and functioning in older age.

Surface Passivation of CdZnTe Detector by Hydrogen Peroxide Solution Etching

NASA Technical Reports Server (NTRS)

Hayes, M.; Chen, H.; Chattopadhyay, K.; Burger, A.; James, R. B.

1998-01-01

The spectral resolution of room temperature nuclear radiation detectors such as CdZnTe is usually limited by the presence of conducting surface species that increase the surface leakage current. Studies have shown that the leakage current can be reduced by proper surface preparation. In this study, we try to optimize the performance of CdZnTe detector by etching the detector with hydrogen peroxide solution as function of concentration and etching time. The passivation effect that hydrogen peroxide introduces have been investigated by current-voltage (I-V) measurement on both parallel strips and metal-semiconductor-metal configurations. The improvements on the spectral response of Fe-55 and 241Am due to hydrogen peroxide treatment are presented and discussed.

Walking in the city.

DOT National Transportation Integrated Search

2013-06-01

Motivated by traffic congestion, excessive energy use and poor health outcomes, planning and public health researchers have developed an extensive body of research that examines walking and other active transport as well as walking for recreation. In...

Acceptorless dehydrogenation of small molecules through cooperative base metal catalysis

PubMed Central

West, Julian G.; Huang, David; Sorensen, Erik J.

2015-01-01

The dehydrogenation of unactivated alkanes is an important transformation both in industrial and biological systems. Recent efforts towards this reaction have revolved around high temperature, organometallic C–H activation by noble metal catalysts that produce alkenes and hydrogen gas as the sole products. Conversely, natural desaturase systems proceed through stepwise hydrogen atom transfer at physiological temperature; however, these transformations require a terminal oxidant. Here we show combining tetra-n-butylammonium decatungstate (TBADT) and cobaloxime pyridine chloride (COPC) can catalytically dehydrogenate unactivated alkanes and alcohols under near-UV irradiation at room temperature with hydrogen as the sole by-product. This noble metal-free process follows a nature-inspired pathway of high- and low-energy hydrogen atom abstractions. The hydrogen evolution ability of cobaloximes is leveraged to render the system catalytic, with cooperative turnover numbers up to 48 and yields up to 83%. Our results demonstrate how cooperative base metal catalysis can achieve transformations previously restricted to precious metal catalysts. PMID:26656087

Chopper-stabilized phase detector

NASA Technical Reports Server (NTRS)

Hopkins, P. M.

1978-01-01

Phase-detector circuit for binary-tracking loops and other binary-data acquisition systems minimizes effects of drift, gain imbalance, and voltage offset in detector circuitry. Input signal passes simultaneously through two channels where it is mixed with early and late codes that are alternately switched between channels. Code switching is synchronized with polarity switching of detector output of each channel so that each channel uses each detector for half time. Net result is that dc offset errors are canceled, and effect of gain imbalance is simply change in sensitivity.

Walking Capacity of Bariatric Surgery Candidates

PubMed Central

King, WC; Engel, SG; Elder, KA; Chapman, WH; Eid, GM; Wolfe, BM; Belle, SH

2011-01-01

Background This study characterizes the walking limitations of bariatric surgery candidates by age and body mass index (BMI) and determines factors independently associated with walking capacity. Setting Multi-institutional at research university hospitals in the United States. Methods 2458 participants of the Longitudinal Assessment of Bariatric Surgery study (age: 18-78 y, BMI: 33-94 kg/m2) attended a pre-operative research visit. Walking capacity was measured via self-report and the 400 meter Long Distance Corridor Walk (LDCW). Results Almost two-thirds (64%) of subjects reported limitations walking several blocks, 48% had an objectively-defined mobility deficit, and 16% reported at least some walking aid use. In multivariable analysis, BMI, older age, lower income and greater bodily pain were independently associated (p<.05) with walking aid use, physical discomfort during the LDCW, inability to complete the LDCW, and slower time to complete the LDCW. Female sex, Hispanic ethnicity (but not race), higher resting heart rate, history of smoking, several comoribidities (history of stroke, ischemic heart disease, diabetes, asthma, sleep apnea, venous edema with ulcerations), and depressive symptoms were also independently related (p<.05) to at least one measure of reduced walking capacity. Conclusions Walking limitations are common in bariatric surgery candidates, even among the least severely obese and youngest patients. Physical activity counseling must be tailored to individuals' abilities. While several factors identified in this study (e.g., BMI, age, pain, comorbidities) should be considered, directly assessing walking capacity will facilitate appropriate goal-setting. PMID:21937285

Walking boot assembly

NASA Technical Reports Server (NTRS)

Vykukal, H. C.; Chambers, A. B.; Stjohn, R. H. (Inventor)

1977-01-01

A walking boot assembly particularly suited for use with a positively pressurized spacesuit is presented. A bootie adapted to be secured to the foot of a wearer, an hermetically sealed boot for receiving the bootie having a walking sole, an inner sole, and an upper portion adapted to be attached to an ankle joint of a spacesuit, are also described.

CVD diamond detectors for ionizing radiation

NASA Astrophysics Data System (ADS)

Friedl, M.; Adam, W.; Bauer, C.; Berdermann, E.; Bergonzo, P.; Bogani, F.; Borchi, E.; Brambilla, A.; Bruzzi, M.; Colledani, C.; Conway, J.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Dulinski, W.; van Eijk, B.; Fallou, A.; Fizzotti, F.; Foulon, F.; Gan, K. K.; Gheeraert, E.; Grigoriev, E.; Hallewell, G.; Hall-Wilton, R.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Karl, C.; Kass, R.; Knöpfle, K. T.; Krammer, M.; Logiudice, A.; Lu, R.; Manfredi, P. F.; Manfredotti, C.; Marshall, R. D.; Meier, D.; Mishina, M.; Oh, A.; Pan, L. S.; Palmieri, V. G.; Pernegger, H.; Pernicka, M.; Peitz, A.; Pirollo, S.; Polesello, P.; Pretzl, K.; Re, V.; Riester, J. L.; Roe, S.; Roff, D.; Rudge, A.; Schnetzer, S.; Sciortino, S.; Speziali, V.; Stelzer, H.; Stone, R.; Tapper, R. J.; Tesarek, R.; Thomson, G. B.; Trawick, M.; Trischuk, W.; Vittone, E.; Walsh, A. M.; Wedenig, R.; Weilhammer, P.; Ziock, H.; Zoeller, M.; RD42 Collaboration

1999-10-01

In future HEP accelerators, such as the LHC (CERN), detectors and electronics in the vertex region of the experiments will suffer from extreme radiation. Thus radiation hardness is required for both detectors and electronics to survive in this harsh environment. CVD diamond, which is investigated by the RD42 Collaboration at CERN, can meet these requirements. Samples of up to 2×4 cm2 have been grown and refined for better charge collection properties, which are measured with a β source or in a testbeam. A large number of diamond samples has been irradiated with hadrons to fluences of up to 5×10 15 cm-2 to study the effects of radiation. Both strip and pixel detectors were prepared in various geometries. Samples with strip metallization have been tested with both slow and fast readout electronics, and the first diamond pixel detector proved fully functional with LHC electronics.

Self-Avoiding Walks over Adaptive Triangular Grids

NASA Technical Reports Server (NTRS)

Heber, Gerd; Biswas, Rupak; Gao, Guang R.; Saini, Subhash (Technical Monitor)

1998-01-01

In this paper, we present a new approach to constructing a "self-avoiding" walk through a triangular mesh. Unlike the popular approach of visiting mesh elements using space-filling curves which is based on a geometric embedding, our approach is combinatorial in the sense that it uses the mesh connectivity only. We present an algorithm for constructing a self-avoiding walk which can be applied to any unstructured triangular mesh. The complexity of the algorithm is O(n x log(n)), where n is the number of triangles in the mesh. We show that for hierarchical adaptive meshes, the algorithm can be easily parallelized by taking advantage of the regularity of the refinement rules. The proposed approach should be very useful in the run-time partitioning and load balancing of adaptive unstructured grids.

Increasing older adults’ walking through primary care: results of a pilot randomized controlled trial

PubMed Central

Mutrie, Nanette

2012-01-01

Background. Physical activity can positively influence health for older adults. Primary care is a good setting for physical activity promotion. Objective. To assess the feasibility of a pedometer-based walking programme in combination with physical activity consultations. Methods. Design: Two-arm (intervention/control) 12-week randomized controlled trial with a 12-week follow-up for the intervention group. Setting: One general practice in Glasgow, UK. Participants: Participants were aged ≥65 years. The intervention group received two 30-minute physical activity consultations from a trained practice nurse, a pedometer and a walking programme. The control group continued as normal for 12 weeks and then received the intervention. Both groups were followed up at 12 and 24 weeks. Outcome measures: Step counts were measured by sealed pedometers and an activPALTM monitor. Psychosocial variables were assessed and focus groups conducted. Results. The response rate was 66% (187/284), and 90% of those randomized (37/41) completed the study. Qualitative data suggested that the pedometer and nurse were helpful to the intervention. Step counts (activPAL) showed a significant increase from baseline to week 12 for the intervention group, while the control group showed no change. Between weeks 12 and 24, step counts were maintained in the intervention group, and increased for the control group after receiving the intervention. The intervention was associated with improved quality of life and reduced sedentary time. Conclusions. It is feasible to recruit and retain older adults from primary care and help them increase walking. A larger trial is necessary to confirm findings and consider cost-effectiveness. PMID:22843637

Walking and cognition, but not symptoms, correlate with dual task cost of walking in multiple sclerosis.

PubMed

Motl, Robert W; Sosnoff, Jacob J; Dlugonski, Deirdre; Pilutti, Lara A; Klaren, Rachel; Sandroff, Brian M

2014-03-01

Performing a cognitive task while walking results in a reduction of walking performance among persons with MS. To date, very little is known about correlates of this dual task cost (DTC) of walking in MS. We examined walking performance, cognitive processing speed, and symptoms of fatigue, depression, anxiety, and pain as correlates of DTC of walking in MS. 82 persons with MS undertook a 6-min walk test (6MWT) and completed the Symbol Digit Modalities Test (SDMT), Fatigue Severity Scale (FSS), Short-form of the McGill Pain Questionnaire (SF-MPQ), Hospital Anxiety and Depression Scale (HADS), and self-reported Expanded Disability Status Scale (SR-EDSS). The participants completed 4 trials of walking at a self-selected pace on an electronic walkway that recorded spatiotemporal parameters of gait. The first 2 trials were performed without a cognitive task, whereas the second 2 trials were completed while performing a modified Word List Generation task. There were significant and large declines in gait performance with the addition of a cognitive task for velocity (p<.001, η2=.52), cadence (p<.001, η2=.49), and step length (p<.001, η2=.23). 6MWT and SDMT scores correlated with DTC for velocity (r=-.41, p<.001 and r=-.32, p<.001, respectively) and step length (r=-.45, p<.001 and r=-.37, p<.001, respectively); there were no significant associations between FSS, SF-MPQ, and HADS scores with the DTC of walking. Regression analyses indicated that 6MW, but not SDMT, explained variance in DTC for velocity (ΔR2=.11, p<.001) and step length (ΔR2=.13, p<.001), after controlling for SR-EDSS scores. Walking performance might be a target of interventions for reducing the DTC of walking in MS. Copyright © 2013 Elsevier B.V. All rights reserved.

High-Rydberg Xenon Submillimeter-Wave Detector

NASA Technical Reports Server (NTRS)

Chutjian, Ara

1987-01-01

Proposed detector for infrared and submillimeter-wavelength radiation uses excited xenon atoms as Rydberg sensors instead of customary beams of sodium, potassium, or cesium. Chemically inert xenon easily stored in pressurized containers, whereas beams of dangerously reactive alkali metals must be generated in cumbersome, unreliable ovens. Xenon-based detector potential for infrared astronomy and for Earth-orbiter detection of terrestrial radiation sources. Xenon atoms excited to high energy states in two stages. Doubly excited atoms sensitive to photons in submillimeter wavelength range, further excited by these photons, then ionized and counted.

Superconducting Detectors for Superlight Dark Matter.

PubMed

Hochberg, Yonit; Zhao, Yue; Zurek, Kathryn M

2016-01-08

We propose and study a new class of superconducting detectors that are sensitive to O(meV) electron recoils from dark matter-electron scattering. Such devices could detect dark matter as light as the warm dark-matter limit, m(X)≳1  keV. We compute the rate of dark-matter scattering off of free electrons in a (superconducting) metal, including the relevant Pauli blocking factors. We demonstrate that classes of dark matter consistent with terrestrial and cosmological or astrophysical constraints could be detected by such detectors with a moderate size exposure.

Superconducting Detectors for Superlight Dark Matter

NASA Astrophysics Data System (ADS)

Hochberg, Yonit; Zhao, Yue; Zurek, Kathryn M.

2016-01-01

We propose and study a new class of superconducting detectors that are sensitive to O (meV ) electron recoils from dark matter-electron scattering. Such devices could detect dark matter as light as the warm dark-matter limit, mX≳1 keV . We compute the rate of dark-matter scattering off of free electrons in a (superconducting) metal, including the relevant Pauli blocking factors. We demonstrate that classes of dark matter consistent with terrestrial and cosmological or astrophysical constraints could be detected by such detectors with a moderate size exposure.

Coined quantum walks on weighted graphs

NASA Astrophysics Data System (ADS)

Wong, Thomas G.

2017-11-01

We define a discrete-time, coined quantum walk on weighted graphs that is inspired by Szegedy’s quantum walk. Using this, we prove that many lackadaisical quantum walks, where each vertex has l integer self-loops, can be generalized to a quantum walk where each vertex has a single self-loop of real-valued weight l. We apply this real-valued lackadaisical quantum walk to two problems. First, we analyze it on the line or one-dimensional lattice, showing that it is exactly equivalent to a continuous deformation of the three-state Grover walk with faster ballistic dispersion. Second, we generalize Grover’s algorithm, or search on the complete graph, to have a weighted self-loop at each vertex, yielding an improved success probability when l < 3 + 2\\sqrt{2} ≈ 5.828 .

Quantum walk on a chimera graph

NASA Astrophysics Data System (ADS)

Xu, Shu; Sun, Xiangxiang; Wu, Jizhou; Zhang, Wei-Wei; Arshed, Nigum; Sanders, Barry C.

2018-05-01

We analyse a continuous-time quantum walk on a chimera graph, which is a graph of choice for designing quantum annealers, and we discover beautiful quantum walk features such as localization that starkly distinguishes classical from quantum behaviour. Motivated by technological thrusts, we study continuous-time quantum walk on enhanced variants of the chimera graph and on diminished chimera graph with a random removal of vertices. We explain the quantum walk by constructing a generating set for a suitable subgroup of graph isomorphisms and corresponding symmetry operators that commute with the quantum walk Hamiltonian; the Hamiltonian and these symmetry operators provide a complete set of labels for the spectrum and the stationary states. Our quantum walk characterization of the chimera graph and its variants yields valuable insights into graphs used for designing quantum-annealers.

Multicapillary Gas Chromatography-Temperature Modulated Metal Oxide Semiconductor Sensors Array Detector for Monitoring of Volatile Organic Compounds in Closed Atmosphere Using Gaussian Apodization Factor Analysis.

PubMed

Alinoori, Amir Hossein; Masoum, Saeed

2018-05-22

A unique metal oxide semiconductor sensor (MOS) array detector with eight sensors was designed and fabricated in a PTFE chamber as an interface for coupling with multicapillary gas chromatography. This design consists of eight transfer lines with equal length between the multicapillary columns (MCC) and sensors. The deactivated capillary columns were passed through each transfer line and homemade flow splitter to distribute the same gas flow on each sensor. Using the eight ports flow splitter design helps us to equal the length of carrier gas path and flow for each sensor, minimizing the dead volume of the sensor's chamber and increasing chromatographic resolution. In addition to coupling of MCC to MOS array detector and other considerations in hardware design, modulation of MOS temperature was used to increase sensitivity and selectivity, and data analysis was enhanced with adapted Gaussian apodization factor analysis (GAFA) as a multivariate curve resolution algorithm. Continues air sampling and injecting system (CASI) design provides a fast and easily applied method for continues injection of air sample with no additional sample preparation. The analysis cycle time required for each run is less than 300 s. The high sample load and sharp injection with the fast separation by MCC decrease the peak widths and improve detection limits. This homemade customized instrument is an alternative to other time-consuming and expensive technologies for continuous monitoring of outgassing in air samples.

Normal and hemiparetic walking

NASA Astrophysics Data System (ADS)

Pfeiffer, Friedrich; König, Eberhard

2013-01-01

The idea of a model-based control of rehabilitation for hemiparetic patients requires efficient models of human walking, healthy walking as well as hemiparetic walking. Such models are presented in this paper. They include 42 degrees of freedom and allow especially the evaluation of kinetic magnitudes with the goal to evaluate measures for the hardness of hemiparesis. As far as feasible, the simulations have been compared successfully with measurements, thus improving the confidence level for an application in clinical practice. The paper is mainly based on the dissertation [19].

The evaluation of stack metal emissions from hazardous waste incinerators: assessing human exposure through noninhalation pathways.

PubMed Central

Sedman, R M; Polisini, J M; Esparza, J R

1994-01-01

Potential public health effects associated with exposure to metal emissions from hazardous waste incinerators through noninhalation pathways were evaluated. Instead of relying on modeling the movement of toxicants through various environmental media, an approach based on estimating changes from baseline levels of exposure was employed. Changes in soil and water As, Cd, Hg, Pb, Cr, and Be concentrations that result from incinerator emissions were first determined. Estimates of changes in human exposure due to direct contact with shallow soil or the ingestion of surface water were then ascertained. Projected changes in dietary intakes of metals due to incinerator emissions were estimated based on changes from baseline dietary intakes that are monitored in U.S. Food and Drug Administration total diet studies. Changes from baseline intake were deemed to be proportional to the projected changes in soil or surface water metal concentrations. Human exposure to metals emitted from nine hazardous waste incinerators were then evaluated. Metal emissions from certain facilities resulted in tangible human exposure through noninhalation pathways. However, the analysis indicated that the deposition of metals from ambient air would result in substantially greater human exposure through noninhalation pathways than the emissions from most of the facilities. PMID:7925180

Metabolic and Circulatory Responses to Walking and Jogging in Water.