Overcoming an Obstacle in Expanding a UMLS Semantic Type Extent

PubMed Central

Chen, Yan; Gu, Huanying; Perl, Yehoshua; Geller, James

2011-01-01

This paper strives to overcome a major problem encountered by a previous expansion methodology for discovering concepts highly likely to be missing a specific semantic type assignment in the UMLS. This methodology is the basis for an algorithm that presents the discovered concepts to a human auditor for review and possible correction. We analyzed the problem of the previous expansion methodology and discovered that it was due to an obstacle constituted by one or more concepts assigned the UMLS Semantic Network semantic type Classification. A new methodology was designed that bypasses such an obstacle without a combinatorial explosion in the number of concepts presented to the human auditor for review. The new expansion methodology with obstacle avoidance was tested with the semantic type Experimental Model of Disease and found over 500 concepts missed by the previous methodology that are in need of this semantic type assignment. Furthermore, other semantic types suffering from the same major problem were discovered, indicating that the methodology is of more general applicability. The algorithmic discovery of concepts that are likely missing a semantic type assignment is possible even in the face of obstacles, without an explosion in the number of processed concepts. PMID:21925287

Making the workplace a more effective site for prevention of noncommunicable diseases in adults.

PubMed

Tryon, Katherine; Bolnick, Howard; Pomeranz, Jennifer L; Pronk, Nicolaas; Yach, Derek

2014-11-01

Efforts to realize the potential of disease prevention in the United States have fallen behind those of peer countries, and workplace disease prevention is a major gap. This article investigates the reasons for this gap. Literature review and expert discussions. Obstacles to effective use of workplace disease prevention include limited leadership and advocacy, poor alignment of financial incentives, limitations in research quality and investment, regulation that does not support evidence-based practice, and a dearth of community-employer partnerships. We make recommendations to address these obstacles, such as the inclusion of health metrics in corporate reporting, making the workplace a central component of the strategy to combat the effect of noncommunicable diseases, and linking prevention directly benefit businesses' bottom lines.

Combining radiation plus immunotherapy to improve systemic immune response.

PubMed

Cushman, Taylor R; Gomez, Daniel; Kumar, Rachit; Likacheva, Anna; Chang, Joe Y; Cadena, Alex P; Paris, Sebastien; Welsh, James W

2018-02-01

Over the past decade, the fields of oncology have made great strides in therapies. The development of new therapeutics and increased understanding of the role of the immune system in the development and treatment of cancer has led to increased collaboration between oncologic fields. Recent technologic advancements in radiation therapy (RT), including stereotactic beam radiation therapy (SBRT), have improved local control and offer an alternative to surgery for the control of oligometastatic disease. Immunotherapy has proven a promising therapeutic in the treatment of metastatic disease but treatment resistance remains a significant obstacle in the majority of patients. Together, radiation and immunotherapy offer potential to eliminate metastatic disease, reduce time to recurrence and improve overall survival. Major obstacles to these positive outcomes include high tumor burden, intratumoral heterogeneity, and the negative effects of tumor stroma, to name a few. Multimodality treatments are under heavy investigation. Promising data from clinical trials is emerging to highlight the value of RT in combination with immunotherapy. However, the mechanisms behind their synergistic effects remain to be fully elucidated. This review aims to highlight the existing literature and offers hypotheses to explain mechanisms behind the synergy of RT and immunotherapy.

Factors Influencing Obstacle Crossing Performance in Patients with Parkinson's Disease

PubMed Central

Liao, Ying-Yi; Yang, Yea-Ru; Wu, Yih-Ru; Wang, Ray-Yau

2014-01-01

Background Tripping over obstacles is the major cause of falls in community-dwelling patients with Parkinson's disease (PD). Understanding the factors associated with the obstacle crossing behavior may help to develop possible training programs for crossing performance. This study aimed to identify the relationships and important factors determining obstacle crossing performance in patients with PD. Methods Forty-two idiopathic patients with PD (Hoehn and Yahr stages I to III) participated in this study. Obstacle crossing performance was recorded by the Liberty system, a three-dimensional motion capture device. Maximal isometric strength of the lower extremity was measured by a handheld dynamometer. Dynamic balance and sensory integration ability were assessed using the Balance Master system. Movement velocity (MV), maximal excursion (ME), and directional control (DC) were obtained during the limits of stability test to quantify dynamic balance. The sum of sensory organization test (SOT) scores was used to quantify sensory organization ability. Results Both crossing stride length and stride velocity correlated significantly with lower extremity muscle strength, dynamic balance control (forward and sideward), and sum of SOT scores. From the regression model, forward DC and ankle dorsiflexor strength were identified as two major determinants for crossing performance (R2 = .37 to.41 for the crossing stride length, R2 = .43 to.44 for the crossing stride velocity). Conclusions Lower extremity muscle strength, dynamic balance control and sensory integration ability significantly influence obstacle crossing performance. We suggest an emphasis on muscle strengthening exercises (especially ankle dorsiflexors), balance training (especially forward DC), and sensory integration training to improve obstacle crossing performance in patients with PD. PMID:24454723

A wearable multipoint ultrasonic travel aids for visually impaired

NASA Astrophysics Data System (ADS)

Ercoli, Ilaria; Marchionni, Paolo; Scalise, Lorenzo

2013-09-01

In 2010, the World Health Organization estimates that there were about 285 million people in the world with disabling eyesight loss (246 millions are visually impaired (VI) and 39 millions are totally blind). For such users, hits during mobility tasks are the reason of major concerns and can reduce the quality of their life. The white cane is the primary device used by the majority of blind or VI users to explore and possibly avoid obstacles; it can monitor only the ground (< 1m) and it does not provide protection for the legs, the trunk and the head. In this paper, authors propose a novel stand-alone Electronic Travel Aid (ETA) device for obstacle detection based on multi- sensing (by 4 ultrasonic transducers) and a microcontroller. Portability, simplicity, reduced dimensions and cost are among the major pros of the reported system, which can detect and localize (angular position and distance from the user) obstacles eventually present in the volume in front of him and on the ground in front of him.

TCP Pacing Developed

NASA Technical Reports Server (NTRS)

Ivancic, William D.

2002-01-01

Transmission control protocol (TCP) was conceived and designed to run over a variety of communication links, including wireless and high-bandwidth links. However, with recent technological advances in satellite and fiber-optic networks, researchers are reevaluating the flexibility of TCP. The TCP pacing and packet pair probing implementation may help overcome two of the major obstacles identified for efficient bandwidth utilization over communication links with large delay-bandwidth products.

The Effects of Lime, Fertilizer, and Herbicide on Forest Soil Solution Chemistry and Northern Red Oak Radial Growth Following Shelterwood Harvest

Treesearch

Angela M Happel; William E. Sharpe

2004-01-01

Soil acidity, nutrient deficient soils, lack of light penetration, herbivory, and understory competition are the major obstacles encountered in regenerating and sustaining northern red oak. Changes in soils that may occur during soil acidifi- cation include: reduced soil pH, increased availability of aluminum (Al) and manganese (Mn), loss of base cations due to...

Lack of Time as an Obstacle to Women's Education: The Case of Upper Volta.

ERIC Educational Resources Information Center

McSweeney, Brenda Gael; Freedman, Marion

1980-01-01

In Upper Volta, a major nonformal educational program attempted to overcome environment and time obstacles to educational participation by rural girls and women. This article discusses project findings on women's time use, the impact of various labor-saving technologies introduced, and women's participation in and attitudes toward project…

Obstacles to Excellence: Factors Leading to an Exaggerated Sense of Communication Proficiency.

ERIC Educational Resources Information Center

Habbel, David M.

The achievement of excellence in communication is a function of both exposure to the best theory, research, and practice in communication, and the student's level of motivation to learn about communication. A major obstacle to managing conflict and interpersonal relationships successfully in general is the tendency people have to attribute…

Educational Experiences and Transitions of Reentry College Women: Special Considerations for African American Female Students.

ERIC Educational Resources Information Center

Thomas, Veronica G.

2001-01-01

Examined motivators, obstacles, and support systems of reentry college women, particularly African American women. Student surveys indicated that respondents were motivated and excited about college reentry, generally reporting increased self-confidence since returning to school but identifying role overload and role conflict as major obstacles.…

Neuromyths in Education: What Is Fact and What Is Fiction for Portuguese Teachers?

ERIC Educational Resources Information Center

Rato, Joana Rodrigues; Abreu, Ana Maria; Castro-Caldas, Alexandre

2013-01-01

Background: Educational neuroscience is a relatively new discipline. However, many obstacles persist in delaying the success of an interface between neuroscience and education. One such major obstacle has been the spread of neuromyths. Purpose: The main aim of this study was to verify whether Portuguese teachers are susceptible to misinterpreting…

Fuzzy Logic Path Planning System for Collision Avoidance by an Autonomous Rover Vehicle

NASA Technical Reports Server (NTRS)

Murphy, Michael G.

1991-01-01

Systems already developed at JSC have shown the benefits of applying fuzzy logic control theory to space related operations. Four major issues are addressed that are associated with developing an autonomous collision avoidance subsystem within a path planning system designed for application in a remote, hostile environment that does not lend itself well to remote manipulation of the vehicle involved through Earth-based telecommunication. A good focus for this is unmanned exploration of the surface of Mars. The uncertainties involved indicate that robust approaches such as fuzzy logic control are particularly appropriate. The four major issues addressed are: (1) avoidance of a single fuzzy moving obstacle; (2) back off from a dead end in a static obstacle environment; (3) fusion of sensor data to detect obstacles; and (4) options for adaptive learning in a path planning system.

Proceedings of the Annual Meeting of the North American Chapter of the International Group for the Psychology of Mathematics Education (20th, Raleigh, NC, October 31-November 3, 1998). Volume 2.

ERIC Educational Resources Information Center

Berenson, Sarah, Ed.; Dawkins, Karen, Ed.; Blanton, Maria, Ed.; Coulombe, Wendy, Ed.; Kolb, John, Ed.; Norwood, Karen, Ed.; Stiff, Lee, Ed.

This conference proceedings contains three plenary session reports, 12 working group and 79 research reports, 35 short oral reports, 60 poster session reports, and two discussion group reports. Major papers (excluding "short orals" and "posters") include: (1) "Semantical Obstacles in Mathematics Understanding" (Carlos Arteaga and Manuel Santos);…

Impact of Performance Obstacles on Intensive Care Nurses‘ Workload, Perceived Quality and Safety of Care, and Quality of Working Life

PubMed Central

Gurses, Ayse P; Carayon, Pascale; Wall, Melanie

2009-01-01

Objectives To study the impact of performance obstacles on intensive care nurses‘ workload, quality and safety of care, and quality of working life (QWL). Performance obstacles are factors that hinder nurses‘ capacity to perform their job and that are closely associated with their immediate work system. Data Sources/Study Setting Data were collected from 265 nurses in 17 intensive care units (ICUs) between February and August 2004 via a structured questionnaire, yielding a response rate of 80 percent. Study Design A cross-sectional study design was used. Data were analyzed by correlation analyses and structural equation modeling. Principal Findings Performance obstacles were found to affect perceived quality and safety of care and QWL of ICU nurses. Workload mediated the impact of performance obstacles with the exception of equipment-related issues on perceived quality and safety of care as well as QWL. Conclusions Performance obstacles in ICUs are a major determinant of nursing workload, perceived quality and safety of care, and QWL. In general, performance obstacles increase nursing workload, which in turn negatively affect perceived quality and safety of care and QWL. Redesigning the ICU work system to reduce performance obstacles may improve nurses‘ work. PMID:19207589

Progress and obstacles in the production and application of recombinant lignin-degrading peroxidases

PubMed Central

Lambertz, Camilla; Ece, Selin; Fischer, Rainer; Commandeur, Ulrich

2016-01-01

ABSTRACT Lignin is 1 of the 3 major components of lignocellulose. Its polymeric structure includes aromatic subunits that can be converted into high-value-added products, but this potential cannot yet been fully exploited because lignin is highly recalcitrant to degradation. Different approaches for the depolymerization of lignin have been tested, including pyrolysis, chemical oxidation, and hydrolysis under supercritical conditions. An additional strategy is the use of lignin-degrading enzymes, which imitates the natural degradation process. A versatile set of enzymes for lignin degradation has been identified, and research has focused on the production of recombinant enzymes in sufficient amounts to characterize their structure and reaction mechanisms. Enzymes have been analyzed individually and in combinations using artificial substrates, lignin model compounds, lignin and lignocellulose. Here we consider progress in the production of recombinant lignin-degrading peroxidases, the advantages and disadvantages of different expression hosts, and obstacles that must be overcome before such enzymes can be characterized and used for the industrial processing of lignin. PMID:27295524

Measures for simulator evaluation of a helicopter obstacle avoidance system

NASA Technical Reports Server (NTRS)

Demaio, Joe; Sharkey, Thomas J.; Kennedy, David; Hughes, Micheal; Meade, Perry

1993-01-01

The U.S. Army Aeroflightdynamics Directorate (AFDD) has developed a high-fidelity, full-mission simulation facility for the demonstration and evaluation of advanced helicopter mission equipment. The Crew Station Research and Development Facility (CSRDF) provides the capability to conduct one- or two-crew full-mission simulations in a state-of-the-art helicopter simulator. The CSRDF provides a realistic, full field-of-regard visual environment with simulation of state-of-the-art weapons, sensors, and flight control systems. We are using the CSRDF to evaluate the ability of an obstacle avoidance system (OASYS) to support low altitude flight in cluttered terrain using night vision goggles (NVG). The OASYS uses a laser radar to locate obstacles to safe flight in the aircraft's flight path. A major concern is the detection of wires, which can be difficult to see with NVG, but other obstacles--such as trees, poles or the ground--are also a concern. The OASYS symbology is presented to the pilot on a head-up display mounted on the NVG (NVG-HUD). The NVG-HUD presents head-stabilized symbology to the pilot while allowing him to view the image intensified, out-the-window scene through the HUD. Since interference with viewing through the display is a major concern, OASYS symbology must be designed to present usable obstacle clearance information with a minimum of clutter.

FieldSAFE: Dataset for Obstacle Detection in Agriculture.

PubMed

Kragh, Mikkel Fly; Christiansen, Peter; Laursen, Morten Stigaard; Larsen, Morten; Steen, Kim Arild; Green, Ole; Karstoft, Henrik; Jørgensen, Rasmus Nyholm

2017-11-09

In this paper, we present a multi-modal dataset for obstacle detection in agriculture. The dataset comprises approximately 2 h of raw sensor data from a tractor-mounted sensor system in a grass mowing scenario in Denmark, October 2016. Sensing modalities include stereo camera, thermal camera, web camera, 360 ∘ camera, LiDAR and radar, while precise localization is available from fused IMU and GNSS. Both static and moving obstacles are present, including humans, mannequin dolls, rocks, barrels, buildings, vehicles and vegetation. All obstacles have ground truth object labels and geographic coordinates.

FieldSAFE: Dataset for Obstacle Detection in Agriculture

PubMed Central

Christiansen, Peter; Larsen, Morten; Steen, Kim Arild; Green, Ole; Karstoft, Henrik

2017-01-01

In this paper, we present a multi-modal dataset for obstacle detection in agriculture. The dataset comprises approximately 2 h of raw sensor data from a tractor-mounted sensor system in a grass mowing scenario in Denmark, October 2016. Sensing modalities include stereo camera, thermal camera, web camera, 360∘ camera, LiDAR and radar, while precise localization is available from fused IMU and GNSS. Both static and moving obstacles are present, including humans, mannequin dolls, rocks, barrels, buildings, vehicles and vegetation. All obstacles have ground truth object labels and geographic coordinates. PMID:29120383

Unpinning of spiral waves from rectangular obstacles by stimulated wave trains

NASA Astrophysics Data System (ADS)

Ponboonjaroenchai, Benjamas; Srithamma, Panatda; Kumchaiseemak, Nakorn; Sutthiopad, Malee; Müller, Stefan C.; Luengviriya, Chaiya; Luengviriya, Jiraporn

2017-09-01

Pinned spiral waves are exhibited in many excitable media. In cardiology, lengthened tachycardia correspond to propagating action potential in forms of spiral waves pinned to anatomical obstacles including veins and scares. Thus, elimination such waves is important particularly in medical treatments. We present study of unpinning of a spiral wave by a wave train initiated by periodic stimuli at a given location. The spiral wave is forced to leave the rectangular obstacle when the period of the wave train is shorter than a threshold Tunpin. For small obstacles, Tunpin decreases when the obstacle size is increased. Furthermore, Tunpin depends on the obstacle orientation with respect to the wave train propagation. For large obstacles, Tunpin is independent to the obstacle size. It implies that the orientation of the obstacle plays an important role in the unpinning of the spiral wave, especially for small rectangular obstacles.

Focusing a Transition: A Report by the Defense Business Board

DTIC Science & Technology

2009-01-01

2. NEAR-TERM OBSTACLES THAT COULD HAMPER LONG -TERM SUCCESS .................................................................25 Lowering the Overhead...requiring immediate att ention, (2) near-term obstacles that could hamper long -term success, (3) organizational issues for the Department to address for...begin early – long before January 20th - to avoid major leadership gaps (see Figure 1-2) and unnecessary vulnerabilities to the Department. Department

Virtual reality-based navigation task to reveal obstacle avoidance performance in individuals with visuospatial neglect.

PubMed

Aravind, Gayatri; Darekar, Anuja; Fung, Joyce; Lamontagne, Anouk

2015-03-01

Persons with post-stroke visuospatial neglect (VSN) often collide with moving obstacles while walking. It is not well understood whether the collisions occur as a result of attentional-perceptual deficits caused by VSN or due to post-stroke locomotor deficits. We assessed individuals with VSN on a seated, joystick-driven obstacle avoidance task, thus eliminating the influence of locomotion. Twelve participants with VSN were tested on obstacle detection and obstacle avoidance tasks in a virtual environment that included three obstacles approaching head-on or 30 (°) contralesionally/ipsilesionally. Our results indicate that in the detection task, the contralesional and head-on obstacles were detected at closer proximities compared to the ipsilesional obstacle. For the avoidance task collisions were observed only for the contralesional and head-on obstacle approaches. For the contralesional obstacle approach, participants initiated their avoidance strategies at smaller distances from the obstacle and maintained smaller minimum distances from the obstacles. The distance at detection showed a negative association with the distance at the onset of avoidance strategy for all three obstacle approaches. We conclusion the observation of collisions with contralesional and head-on obstacles, in the absence of locomotor burden, provides evidence that attentional-perceptual deficits due to VSN, independent of post-stroke locomotor deficits, alter obstacle avoidance abilities.

Prediction of the run out extents of the Slano Blato landslide for future debris flow events

NASA Astrophysics Data System (ADS)

Askarinejad, Amin; Leu, Pascal; Macek, Matej; Petkovsek, Ana; Springman, Sarah

2013-04-01

The Slano Blato landslide has a volume of about 1 mio m3 and is located in the western part of Slovenia. It has been considered to be a potential natural hazard for the village of Lokavec for more than 200 years. Several mud flows, exhibiting a range of volumes and velocities, have originated from the landslide body since the year 2000, when the landslide was reactivated due to an intense rainfall event. A series of obstacles, including safety dams and deposition ponds, have been constructed for the remediation of the landslide. These obstacles are designed to absorb and contain future debris flow hazard. A prerequisite to any risk analysis is to establish the vulnerability to the hazard event. The aim of this work is to simulate possible future debris flow scenarios in order to predict the run out distances, flow heights, impact pressures and potential effects on the downstream village buildings and infrastructure. The simulations were carried out using the RAMMS program (RApid Mass MovementS, www.ramms.slf.ch). A three dimensional terrain model of the landslide area and the downstream zones, with or without the inclusion of the obstacles, was made for the simulations and different scenarios concerning the released volume, the internal friction and viscosity of the sliding mass were studied. The results indicate that low viscosity mudflows with a volume of 5,000 m3 endanger some parts of Lokavec village. However, the simulations with volumes of 15,000 and 50,000 m3 predict catastrophic effects in terms of either impact pressures or deposition heights for the majority of houses. Moreover, the simulations confirmed that the choice of the material properties (internal friction and viscosity), the characteristics of the release hydrograph, event location, and natural or man-made obstacles play major roles in the run out distances and impact pressures.

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

Klepper, O.H.

One of the major obstacles to extensive application of nuclear power to industrial heat is the difference between the relatively small energy requirements of individual industrial plants and the large thermal capacity of current power reactors. A practical way of overcoming this obstacle would be to operate a centrally located dual-purpose power plant that would furnish process steam to a cluster of industrial plants, in addition to generating electrical power. The present study indicates that even relatively remote industrial plants could be served by the power plant, since it might be possible to convey steam economically as much as tenmore » miles or more. A survey of five major industries indicates a major potential market for industrial steam from large nuclear power stations.« less

Common Challenges Faced by Women of Color in Physics, and Actions Faculty Can Take to Minimize Those Challenges

NASA Astrophysics Data System (ADS)

Johnson, Angela; Ong, Maria; Ko, Lily T.; Smith, Janet; Hodari, Apriel

2017-09-01

Women of color are deeply underrepresented in physics. Between 2002 and 2012, only 1% of graduating physics majors were Black women and another 1% were Latinas; only 61 American Indian women total completed degrees in physics in those years (out of 48,000 physics majors). This isolation can lead to additional obstacles that women of color majoring in physics must face above and beyond the challenging material. In this article we draw on qualitative findings to describe common obstacles women of color face. However, departments can take deliberate steps so that underrepresentation need not turn into loneliness and isolation. We describe the characteristics of a department where women of color report that they are thriving. We end with concrete steps physics faculty can take to support women physics majors of color.

Prevention 0f Unwanted Free-Declaration of Static Obstacles in Probability Occupancy Grids

NASA Astrophysics Data System (ADS)

Krause, Stefan; Scholz, M.; Hohmann, R.

2017-10-01

Obstacle detection and avoidance are major research fields in unmanned aviation. Map based obstacle detection approaches often use discrete world representations such as probabilistic grid maps to fuse incremental environment data from different views or sensors to build a comprehensive representation. The integration of continuous measurements into a discrete representation can result in rounding errors which, in turn, leads to differences between the artificial model and real environment. The cause of these deviations is a low spatial resolution of the world representation comparison to the used sensor data. Differences between artificial representations which are used for path planning or obstacle avoidance and the real world can lead to unexpected behavior up to collisions with unmapped obstacles. This paper presents three approaches to the treatment of errors that can occur during the integration of continuous laser measurement in the discrete probabilistic grid. Further, the quality of the error prevention and the processing performance are compared with real sensor data.

Inertial navigation sensor integrated obstacle detection system

NASA Technical Reports Server (NTRS)

Bhanu, Bir (Inventor); Roberts, Barry A. (Inventor)

1992-01-01

A system that incorporates inertial sensor information into optical flow computations to detect obstacles and to provide alternative navigational paths free from obstacles. The system is a maximally passive obstacle detection system that makes selective use of an active sensor. The active detection typically utilizes a laser. Passive sensor suite includes binocular stereo, motion stereo and variable fields-of-view. Optical flow computations involve extraction, derotation and matching of interest points from sequential frames of imagery, for range interpolation of the sensed scene, which in turn provides obstacle information for purposes of safe navigation.

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

Zou, Yun; Zhang, Lehao; Li, Yang

Limitations of strength and formability are the major obstacles to the industrial application of magnesium alloys. Here, we demonstrate, by producing the duplex phases and fine intermetallic particles in composition-optimized superlight Mg-Li-Al alloys, a unique approach to simultaneously improve the comprehensive mechanical properties (a strength-ductility balance). In conclusion, the phase components and microstructures, including the size, morphology, and distribution of precipitated-intermetallic particles can be optimized by tuning the Li content, which strongly influences the work-hardening behavior and tension-compression yield asymmetry.

Teaching Elementary Accounting to Non-Accounting Majors

ERIC Educational Resources Information Center

Lloyd, Cynthia B.; Abbey, Augustus

2009-01-01

A central recurring theme in business education is the optimal strategy for improving introductory accounting, the gateway subject of business education. For many students, especially non-accounting majors, who are required to take introductory accounting as a requirement of the curriculum, introductory accounting has become a major obstacle for…

Critical Care Nurses' Suggestions to Improve End-of-Life Care Obstacles: Minimal Change Over 17 Years.

PubMed

Beckstrand, Renea L; Hadley, Kacie Hart; Luthy, Karlen E; Macintosh, Janelle L B

Critical-care nurses (CCNs) provide end-of-life (EOL) care on a daily basis as 1 in 5 patients dies while in intensive care units. Critical-care nurses overcome many obstacles to perform quality EOL care for dying patients. The purposes of this study were to collect CCNs' current suggestions for improving EOL care and determine if EOL care obstacles have changed by comparing results to data gathered in 1998. A 72-item questionnaire regarding EOL care perceptions was mailed to a national, geographically dispersed, random sample of 2000 members of the American Association of Critical-Care Nurses. One of 3 qualitative questions asked CCNs for suggestions to improve EOL care. Comparative obstacle size (quantitative) data were previously published. Of the 509 returned questionnaires, 322 (63.3%) had 385 written suggestions for improving EOL care. Major themes identified were ensuring characteristics of a good death, improving physician communication with patients and families, adjusting nurse-to-patient ratios to 1:1, recognizing and avoiding futile care, increasing EOL education, physicians who are present and "on the same page," not allowing families to override patients' wishes, and the need for more support staff. When compared with data gathered 17 years previously, major themes remained the same but in a few cases changed in order and possible causation. Critical-care nurses' suggestions were similar to those recommendations from 17 years ago. Although the order of importance changed minimally, the number of similar themes indicated that obstacles to providing EOL care to dying intensive care unit patients continue to exist over time.

Age-associated changes in obstacle negotiation strategies: Does size and timing matter?

PubMed

Maidan, I; Eyal, S; Kurz, I; Geffen, N; Gazit, E; Ravid, L; Giladi, N; Mirelman, A; Hausdorff, J M

2018-01-01

Tripping over an obstacle is one of the most common causes of falls among older adults. However, the effects of aging, obstacle height and anticipation time on negotiation strategies have not been systematically evaluated. Twenty older adults (ages: 77.7±3.4years; 50% women) and twenty young adults (age: 29.3±3.8years; 50% women) walked through an obstacle course while negotiating anticipated and unanticipated obstacles at heights of 25mm and 75mm. Kinect cameras captured the: (1) distance of the subject's trailing foot before the obstacles, (2) distance of the leading foot after the obstacles, (3) clearance of the leading foot above the obstacles, and (4) clearance of the trailing foot above the obstacles. Linear-mix models assessed changes between groups and conditions. Older adults placed their leading foot closer to the obstacle after landing, compared to young adults (p<0.001). This pattern was enhanced in high obstacles (group*height interaction, p=0.033). Older adults had lower clearance over the obstacles, compared to young adults (p=0.007). This was more pronounced during unanticipated obstacles (group*ART interaction, p=0.003). The distance of the leading foot and clearance of the trailing foot after the obstacles were correlated with motor, cognitive, and functional abilities. These findings suggest that there are age-related changes in obstacle crossing strategies that are dependent on the specific characteristics of the obstacle. The results have important implications for clinical practice, suggesting that functional exercise should include obstacle negotiation training with variable practice of height and available response times. Further studies are needed to better understand the effects of motor and cognitive abilities. Copyright © 2017 Elsevier B.V. All rights reserved.

An Information-Centric Approach to Autonomous Trajectory Planning Utilizing Optimal Control Techniques

DTIC Science & Technology

2009-09-01

to promote one way as the best, but to show there are several ways to define the problem. 107 Figure 71. Final Orientation/Obstacle Scenario...a comparison of the running cost vs. distance from an obstacle for varying values of p. Simulations have shown that for 4p  , the running cost...sliding door example. This scenario shows a major weakness when conducting trajectory planning using snapshots in a dynamic environment

Determination of Misconceptions Belonging to the "Solar System and Beyond: Space Puzzle" Unit in 7th Grade Science and Technology Curriculum with Two-Tier Diagnostic Tests

ERIC Educational Resources Information Center

Töman, Ögr. Gör. Ufuk; Ergen, Yusuf

2014-01-01

Today's World is in period of rapid development of science and technology. There is science and technology education that not based on rote, practical on the basis of development in science and technology. Misconceptions are a major obstacle in order to take the desired efficiency. Because concepts that learned wrong obstacle attainment of right…

Identifying Obstacles to Adoption in New York State's Out-of-Home Care System.

ERIC Educational Resources Information Center

Avery, Rosemary J.

1999-01-01

This study queried caseworkers for 77 New York children in out-of-home care still waiting for placement to determine obstacles to permanent adoption. Questionnaires sought demographics, placement efforts, and caseworker opinions. Findings indicated several obstacles, including the following: child's strong emotional ties to family (foster or…

High Throughput Sequencing for Detection of Foodborne Pathogens

PubMed Central

Sekse, Camilla; Holst-Jensen, Arne; Dobrindt, Ulrich; Johannessen, Gro S.; Li, Weihua; Spilsberg, Bjørn; Shi, Jianxin

2017-01-01

High-throughput sequencing (HTS) is becoming the state-of-the-art technology for typing of microbial isolates, especially in clinical samples. Yet, its application is still in its infancy for monitoring and outbreak investigations of foods. Here we review the published literature, covering not only bacterial but also viral and Eukaryote food pathogens, to assess the status and potential of HTS implementation to inform stakeholders, improve food safety and reduce outbreak impacts. The developments in sequencing technology and bioinformatics have outpaced the capacity to analyze and interpret the sequence data. The influence of sample processing, nucleic acid extraction and purification, harmonized protocols for generation and interpretation of data, and properly annotated and curated reference databases including non-pathogenic “natural” strains are other major obstacles to the realization of the full potential of HTS in analytical food surveillance, epidemiological and outbreak investigations, and in complementing preventive approaches for the control and management of foodborne pathogens. Despite significant obstacles, the achieved progress in capacity and broadening of the application range over the last decade is impressive and unprecedented, as illustrated with the chosen examples from the literature. Large consortia, often with broad international participation, are making coordinated efforts to cope with many of the mentioned obstacles. Further rapid progress can therefore be prospected for the next decade. PMID:29104564

Blindness enhances auditory obstacle circumvention: Assessing echolocation, sensory substitution, and visual-based navigation

PubMed Central

Scarfe, Amy C.; Moore, Brian C. J.; Pardhan, Shahina

2017-01-01

Performance for an obstacle circumvention task was assessed under conditions of visual, auditory only (using echolocation) and tactile (using a sensory substitution device, SSD) guidance. A Vicon motion capture system was used to measure human movement kinematics objectively. Ten normally sighted participants, 8 blind non-echolocators, and 1 blind expert echolocator navigated around a 0.6 x 2 m obstacle that was varied in position across trials, at the midline of the participant or 25 cm to the right or left. Although visual guidance was the most effective, participants successfully circumvented the obstacle in the majority of trials under auditory or SSD guidance. Using audition, blind non-echolocators navigated more effectively than blindfolded sighted individuals with fewer collisions, lower movement times, fewer velocity corrections and greater obstacle detection ranges. The blind expert echolocator displayed performance similar to or better than that for the other groups using audition, but was comparable to that for the other groups using the SSD. The generally better performance of blind than of sighted participants is consistent with the perceptual enhancement hypothesis that individuals with severe visual deficits develop improved auditory abilities to compensate for visual loss, here shown by faster, more fluid, and more accurate navigation around obstacles using sound. PMID:28407000

Blindness enhances auditory obstacle circumvention: Assessing echolocation, sensory substitution, and visual-based navigation.

PubMed

Kolarik, Andrew J; Scarfe, Amy C; Moore, Brian C J; Pardhan, Shahina

2017-01-01

Performance for an obstacle circumvention task was assessed under conditions of visual, auditory only (using echolocation) and tactile (using a sensory substitution device, SSD) guidance. A Vicon motion capture system was used to measure human movement kinematics objectively. Ten normally sighted participants, 8 blind non-echolocators, and 1 blind expert echolocator navigated around a 0.6 x 2 m obstacle that was varied in position across trials, at the midline of the participant or 25 cm to the right or left. Although visual guidance was the most effective, participants successfully circumvented the obstacle in the majority of trials under auditory or SSD guidance. Using audition, blind non-echolocators navigated more effectively than blindfolded sighted individuals with fewer collisions, lower movement times, fewer velocity corrections and greater obstacle detection ranges. The blind expert echolocator displayed performance similar to or better than that for the other groups using audition, but was comparable to that for the other groups using the SSD. The generally better performance of blind than of sighted participants is consistent with the perceptual enhancement hypothesis that individuals with severe visual deficits develop improved auditory abilities to compensate for visual loss, here shown by faster, more fluid, and more accurate navigation around obstacles using sound.

Obstacle detectors for automated transit vehicles: A technoeconomic and market analysis

NASA Technical Reports Server (NTRS)

Lockerby, C. E.

1979-01-01

A search was conducted to identify the technical and economic characteristics of both NASA and nonNASA obstacle detectors. The findings, along with market information were compiled and analyzed for consideration by DOT and NASA in decisions about any future automated transit vehicle obstacle detector research, development, or applications project. Currently available obstacle detectors and systems under development are identified by type (sonic, capacitance, infrared/optical, guided radar, and probe contact) and compared with the three NASA devices selected as possible improvements or solutions to the problems in existing obstacle detection systems. Cost analyses and market forecasts individually for the AGT and AMTV markets are included.

The Magsat magnetometer boom

NASA Technical Reports Server (NTRS)

Smola, J. F.; Radford, W. E.; Reitz, M. H.

1980-01-01

A lightweight extendable structure that can precisely position magnetically sensitive instruments safe distances from magnetic sources in a spacecraft is described as well as the major areas of concern that played dominant roles in its development. Weight, packaging volume, thermal distortion, mechanical misalignments, dimensional instability, launch environments, and low temperature functioning were areas that presented some formidable obstacles. The ways in which these obstacles were dealt with are examined for those involving the development of similar aerospace mechanisms with equally restrictive requirements.

Fresnel diffraction by spherical obstacles

NASA Technical Reports Server (NTRS)

Hovenac, Edward A.

1989-01-01

Lommel functions were used to solve the Fresnel-Kirchhoff diffraction integral for the case of a spherical obstacle. Comparisons were made between Fresnel diffraction theory and Mie scattering theory. Fresnel theory is then compared to experimental data. Experiment and theory typically deviated from one another by less than 10 percent. A unique experimental setup using mercury spheres suspended in a viscous fluid significantly reduced optical noise. The major source of error was due to the Gaussian-shaped laser beam.

Obstacles to the Termination of Air Force Activities.

DTIC Science & Technology

1986-04-01

sugsts how. it the Air Force leadership con- eludes that termination is necessary the Air Force can surmount the obstacles.’ The stud v was cMIduct ed...the Air Force leadership concludes that the termination of a major activity is a promising or necessary management option, the report suggests that it...complicated inter- nal political process; it takes time to work out. The top leadership should begin the process of corporate strategy building and priority

Does physical exercise improve obstacle negotiation in the elderly? A systematic review.

PubMed

Guadagnin, Eliane C; da Rocha, Emmanuel S; Duysens, Jacques; Carpes, Felipe P

2016-01-01

Physical exercise improves walking in the elderly but much less is known about its effect on more challenged gait, such as obstacle negotiation. We conducted a systematic review to discuss the effects of regular physical exercise on kinematics and kinetics of obstacle negotiation in the elderly. A comprehensive literature search revealed 859 citations for review, whereof 206 studies entered the full-text analysis. After application of inclusion and exclusion criteria, 13 studies were included in this systematic review. Most of them presented a reasonable quality (average 0.68) but none of them reached the level of a randomized control trial. Interventions were heterogeneous, with training periods lasting from 5 days to 10 months. Studies assessed obstacle negotiation basically considering 3 types of testing paradigm, namely a walkway with either a single obstacle crossing, or with multiple obstacles, or else a treadmill with an obstacle avoidance task under time pressure. In general, longer training programs had better results and very short ones were not effective. A weekly frequency of 2-3 times was the most common among the studies showing positive effects. Regardless of exercises types performed, most of them were effective and so far, there is no consensus about the best exercise for improving obstacle negotiation. A lack of studies on this topic still is evident. Including a record of fall score can further help in deciding which programs are to be preferred. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Imaging approaches for the study of cell based cardiac therapies

PubMed Central

Lau, Joe F.; Anderson, Stasia A.; Adler, Eric; Frank, Joseph A.

2009-01-01

Despite promising preclinical data, the treatment of cardiovascular diseases using embryonic, bone-marrow-derived, and skeletal myoblast stem cells has not yet come to fruition within mainstream clinical practice. Major obstacles in cardiac stem cell investigations include the ability to monitor cell engraftment and survival following implantation within the myocardium. Several cellular imaging modalities, including reporter gene and MRI-based tracking approaches, have emerged that provide the means to identify, localize and monitor stem cells longitudinally in vivo following implantation. This Review will examine the various cardiac cellular tracking modalities, including the combinatorial use of several probes in multimodality imaging, with a focus on data from the last five years. PMID:20027188

Effects of soft interactions and bound mobility on diffusion in crowded environments: a model of sticky and slippery obstacles

NASA Astrophysics Data System (ADS)

Stefferson, Michael W.; Norris, Samantha L.; Vernerey, Franck J.; Betterton, Meredith D.; E Hough, Loren

2017-08-01

Crowded environments modify the diffusion of macromolecules, generally slowing their movement and inducing transient anomalous subdiffusion. The presence of obstacles also modifies the kinetics and equilibrium behavior of tracers. While previous theoretical studies of particle diffusion have typically assumed either impenetrable obstacles or binding interactions that immobilize the particle, in many cellular contexts bound particles remain mobile. Examples include membrane proteins or lipids with some entry and diffusion within lipid domains and proteins that can enter into membraneless organelles or compartments such as the nucleolus. Using a lattice model, we studied the diffusive movement of tracer particles which bind to soft obstacles, allowing tracers and obstacles to occupy the same lattice site. For sticky obstacles, bound tracer particles are immobile, while for slippery obstacles, bound tracers can hop without penalty to adjacent obstacles. In both models, binding significantly alters tracer motion. The type and degree of motion while bound is a key determinant of the tracer mobility: slippery obstacles can allow nearly unhindered diffusion, even at high obstacle filling fraction. To mimic compartmentalization in a cell, we examined how obstacle size and a range of bound diffusion coefficients affect tracer dynamics. The behavior of the model is similar in two and three spatial dimensions. Our work has implications for protein movement and interactions within cells.

Obstacle Characterization in a Geocrowdsourced Accessibility System

NASA Astrophysics Data System (ADS)

Qin, H.; Aburizaiza, A. O.; Rice, R. M.; Paez, F.; Rice, M. T.

2015-08-01

Transitory obstacles - random, short-lived and unpredictable objects - are difficult to capture in any traditional mapping system, yet they have significant negative impacts on the accessibility of mobility- and visually-impaired individuals. These transitory obstacles include sidewalk obstructions, construction detours, and poor surface conditions. To identify these obstacles and assist the navigation of mobility- and visually- impaired individuals, crowdsourced mapping applications have been developed to harvest and analyze the volunteered obstacles reports from local students, faculty, staff, and residents. In this paper, we introduce a training program designed and implemented for recruiting and motivating contributors to participate in our geocrowdsourced accessibility system, and explore the quality of geocrowdsourced data with a comparative analysis methodology.

Effects of buried obstacles on penetration resistance in cohesionless soils

NASA Technical Reports Server (NTRS)

Deluca, E. W.; Carrasco, L. H.

1972-01-01

Recent experiments concerning penetration of cohesionless soils in special molds that include solid obstacles embedded within the soil matrix are reported. The relative effects of these obstacles with respect to the soil properties of relative density, texture, and gradation are also discussed. Because lunar soil is fairly cohesionless, special attention was given to the Apollo lunar simulant, AP-12.

Obstacles and Affordances for Integer Reasoning: An Analysis of Children's Thinking and the History of Mathematics

ERIC Educational Resources Information Center

Bishop, Jessica Pierson; Lamb, Lisa L.; Philipp, Randolph A.; Whitacre, Ian; Schappelle, Bonnie P.; Lewis, Melinda L.

2014-01-01

We identify and document 3 cognitive obstacles, 3 cognitive affordances, and 1 type of integer understanding that can function as either an obstacle or affordance for learners while they extend their numeric domains from whole numbers to include negative integers. In particular, we highlight 2 key subsets of integer reasoning: understanding or…

Prophetic Naming as Informal Adult Education: Decolonizing the Imagination with Boston's New Majority

ERIC Educational Resources Information Center

Klimczak, Susan Ann

2009-01-01

This is an educational ethnography of collective informal learning and education in social movements based on five years of participant observation among Boston's New Majority from 2003-2009. The New Majority is a "movement of movements" and an organization of People of Color in Boston that seek to address an egregious obstacle to…

Hydraulic fracturing to enhance the remediation of DNAPL in low permeability soils

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

Murdoch, L.; Slack, B.

1996-08-01

Meager rates of fluid flow are a major obstacle to in situ remediation of low permeability soils. This paper describes methods designed to avoid that obstacle by creating fractures and filling them with sand to increase well discharge and change paths of fluid flow in soil. Gently dipping fractures 10 m in maximum dimension and 1 to 2 cm thick can be created in some contaminated soils at depths of a few in or greater. Hydraulic fractures can also be used to create electrically conductive layers or to deliver granules of chemically or biologically active compounds that will degrade contaminantsmore » in place. Benefits of applying hydraulic fractures to DNAPL recovery include rates of fluid recovery, enhancing upward gradients to improve hydrodynamic stabilization, forming flat-lying reactive curtains to intersect compounds moving downward, or improving the performance of electrokinetics intended to recover compounds dissolved in water. 30 refs., 7 figs., 1 tab.« less

Disaster Planning and Risk Communication With Vulnerable Communities: Lessons From Hurricane Katrina

PubMed Central

Eisenman, David P.; Cordasco, Kristina M.; Asch, Steve; Golden, Joya F.; Glik, Deborah

2007-01-01

Objectives. We studied the experience of Hurricane Katrina evacuees to better understand factors influencing evacuation decisions in impoverished, mainly minority communities that were most severely affected by the disaster. Methods. We performed qualitative interviews with 58 randomly selected evacuees living in Houston’s major evacuation centers from September 9 to 12, 2005. Transcripts were content analyzed using grounded theory methodology. Results. Participants were mainly African American, had low incomes, and were from New Orleans. Participants’ strong ties to extended family, friends, and community groups influenced other factors affecting evacuation, including transportation, access to shelter, and perception of evacuation messages. These social connections cut both ways, which facilitated and hindered evacuation decisions. Conclusions. Effective disaster plans must account for the specific obstacles encountered by vulnerable and minority communities. Removing the more apparent obstacles of shelter and transportation will likely be insufficient for improving disaster plans for impoverished, minority communities. The important influence of extended families and social networks demand better community-based communication and preparation strategies. PMID:17413069

Multiple measures could alleviate long-branch attraction in phylogenomic reconstruction of Cupressoideae (Cupressaceae)

PubMed Central

Qu, Xiao-Jian; Jin, Jian-Jun; Chaw, Shu-Miaw; Li, De-Zhu; Yi, Ting-Shuang

2017-01-01

Long-branch attraction (LBA) is a major obstacle in phylogenetic reconstruction. The phylogenetic relationships among Juniperus (J), Cupressus (C) and the Hesperocyparis-Callitropsis-Xanthocyparis (HCX) subclades of Cupressoideae are controversial. Our initial analyses of plastid protein-coding gene matrix revealed both J and C with much longer stem branches than those of HCX, so their sister relationships may be attributed to LBA. We used multiple measures including data filtering and modifying, evolutionary model selection and coalescent phylogenetic reconstruction to alleviate the LBA artifact. Data filtering by strictly removing unreliable aligned regions and removing substitution saturation genes and rapidly evolving sites could significantly reduce branch lengths of subclades J and C and recovered a relationship of J (C, HCX). In addition, using coalescent phylogenetic reconstruction could elucidate the LBA artifact and recovered J (C, HCX). However, some valid methods for other taxa were inefficient in alleviating the LBA artifact in J-C-HCX. Different strategies should be carefully considered and justified to reduce LBA in phylogenetic reconstruction of different groups. Three subclades of J-C-HCX were estimated to have experienced ancient rapid divergence within a short period, which could be another major obstacle in resolving relationships. Furthermore, our plastid phylogenomic analyses fully resolved the intergeneric relationships of Cupressoideae. PMID:28120880

Multiple measures could alleviate long-branch attraction in phylogenomic reconstruction of Cupressoideae (Cupressaceae).

PubMed

Qu, Xiao-Jian; Jin, Jian-Jun; Chaw, Shu-Miaw; Li, De-Zhu; Yi, Ting-Shuang

2017-01-25

Long-branch attraction (LBA) is a major obstacle in phylogenetic reconstruction. The phylogenetic relationships among Juniperus (J), Cupressus (C) and the Hesperocyparis-Callitropsis-Xanthocyparis (HCX) subclades of Cupressoideae are controversial. Our initial analyses of plastid protein-coding gene matrix revealed both J and C with much longer stem branches than those of HCX, so their sister relationships may be attributed to LBA. We used multiple measures including data filtering and modifying, evolutionary model selection and coalescent phylogenetic reconstruction to alleviate the LBA artifact. Data filtering by strictly removing unreliable aligned regions and removing substitution saturation genes and rapidly evolving sites could significantly reduce branch lengths of subclades J and C and recovered a relationship of J (C, HCX). In addition, using coalescent phylogenetic reconstruction could elucidate the LBA artifact and recovered J (C, HCX). However, some valid methods for other taxa were inefficient in alleviating the LBA artifact in J-C-HCX. Different strategies should be carefully considered and justified to reduce LBA in phylogenetic reconstruction of different groups. Three subclades of J-C-HCX were estimated to have experienced ancient rapid divergence within a short period, which could be another major obstacle in resolving relationships. Furthermore, our plastid phylogenomic analyses fully resolved the intergeneric relationships of Cupressoideae.

Women's orgasm obstacles: A qualitative study.

PubMed

Nekoolaltak, Maryam; Keshavarz, Zohreh; Simbar, Masoumeh; Nazari, Ali Mohammad; Baghestani, Ahmad Reza

2017-08-01

Woman's orgasm plays a vital role in sexual compatibility and marital satisfaction. Orgasm in women is a learnable phenomenon that is influenced by several factors. The aim of this study is exploring obstacles to orgasm in Iranian married women. This qualitative study with directed content analysis approach was conducted in 2015-2016, on 20 Iranian married women who were individually interviewed at two medical clinics in Tehran, Iran. Orgasm obstacles were explored in one category, 4 subcategories, and 25 codes. The main category was "Multidimensionality of women's orgasm obstacles". Subcategories and some codes included: Physical obstacles (wife's or husband's boredom, vaginal infection, insufficient vaginal lubrication), psychological obstacles (lack of sexual knowledge, shame, lack of concentration on sex due to household and children problems), relational obstacles (husband's hurry, having a dispute and annoyance with spouse) and contextual obstacles (Irregular sleep hours, lack of privacy and inability to separate children's bedroom from their parents, lack of peace at home). For prevention or treatment of female orgasm disorders, attention to physical factors is not enough. Obtaining a comprehensive history about physical, psychological, relational and contextual dimensions of woman's life is necessary.

Assessing the ground vibrations produced by a heavy vehicle traversing a traffic obstacle.

PubMed

Ducarne, Loïc; Ainalis, Daniel; Kouroussis, Georges

2018-01-15

Despite advancements in alternative transport networks, road transport remains the dominant mode in many modern and developing countries. The ground-borne motions produced by the passage of a heavy vehicle over a geometric obstacle (e.g. speed hump, train tracks) pose a fundamental problem in transport annoyance in urban areas. In order to predict the ground vibrations generated by the passage of a heavy vehicle over a geometric obstacle, a two-step numerical model is developed. The first step involves simulating the dynamic loads generated by the heavy vehicle using a multibody approach, which includes the tyre-obstacle-ground interaction. The second step involves the simulation of the ground wave propagation using a three dimensional finite element model. The simulation is able to be decoupled due to the large difference in stiffness between the vehicle's tyres and the road. First, the two-step model is validated using an experimental case study available in the literature. A sensitivity analysis is then presented, examining the influence of various factors on the generated ground vibrations. Factors investigated include obstacle shape, obstacle dimensions, vehicle speed, and tyre stiffness. The developed model can be used as a tool in the early planning stages to predict the ground vibrations generated by the passage of a heavy vehicle over an obstacle in urban areas. Copyright © 2017 Elsevier B.V. All rights reserved.

Oil-Free Shaft Support System Rotordynamics: Past, Present, and Future Challenges and Opportunities

NASA Technical Reports Server (NTRS)

DellaCorte, Christopher

2011-01-01

Recent breakthroughs in Oil-Free technologies have enabled new high-speed rotor systems and turbomachinery. Such technologies can include compliant-surface gas bearings, magnetic bearings, and advanced solid lubricants and tribo-materials. This presentation briefly reviews critical technology developments and the current state-of-the-art, emerging Oil-Free rotor systems and discusses obstacles preventing more widespread use. Key examples of "best practices" for deploying Oil-Free technologies will be presented and remaining major technical questions surrounding Oil-Free technologies will be brought forward.

Parental expectations and outcomes of pediatric cochlear implantation.

PubMed

Piazza, Elizabeth; Kandathil, Cherian; Carron, Jeffrey D

2009-10-01

Cochlear implants have been used with increasing frequency over the past twenty years, including very young patients. To determine if parents are satisfied with their children's performance after cochlear implantation. Survey mailed to parents of children receiving cochlear implants. 31 questionnaires were returned out of 69 mailed (45 %). The vast majority of responding parents felt that their children benefited substantially from cochlear implant surgery. Cochlear implantation is effective in helping children develop auditory-oral communication skills. Access to auditory/oral communication programs in this state remains an obstacle in postoperative habilitation.

Portable non-invasive brain-computer interface: challenges and opportunities of optical modalities

NASA Astrophysics Data System (ADS)

Scholl, Clara A.; Hendrickson, Scott M.; Swett, Bruce A.; Fitch, Michael J.; Walter, Erich C.; McLoughlin, Michael P.; Chevillet, Mark A.; Blodgett, David W.; Hwang, Grace M.

2017-05-01

The development of portable non-invasive brain computer interface technologies with higher spatio-temporal resolution has been motivated by the tremendous success seen with implanted devices. This talk will discuss efforts to overcome several major obstacles to viability including approaches that promise to improve spatial and temporal resolution. Optical approaches in particular will be highlighted and the potential benefits of both Blood-Oxygen Level Dependent (BOLD) and Fast Optical Signal (FOS) will be discussed. Early-stage research into the correlations between neural activity and FOS will be explored.

Obstacles to colorectal screening in general practice: a qualitative study of GPs and patients.

PubMed

Aubin-Auger, Isabelle; Mercier, Alain; Lebeau, Jean-Pierre; Baumann, Laurence; Peremans, Lieve; Van Royen, Paul

2011-12-01

The faecal occult blood test (FOBT) has proven efficiency at screening populations for an average risk of colorectal cancer. Mortality related to this cancer decreases by 15-18% among adults, 50-74 years old, tested every 2 years. A participation rate of at least 50% is desirable. This rate has not yet been reached in most French regions. To explore the obstacles to mass colorectal screening in France. In 2009, five focus groups were conducted in different areas to explore physicians' obstacles to FOBT screening. The patients' obstacles were assessed in semi-structured interviews. A purposive sampling had been carried out for both GPs and patients. The focus groups were coded using Nvivo 8(®) software by three researchers; the interviews manually coded by two researchers. GPs reported insufficient training and some doubted the relevance of screening. They expressed concern of having insufficient time for the test during a consultation, as well as practical and administrative obstacles. Some GPs experienced difficulty persuading patients who had no signs of colorectal disease. Obstacles for patients were mainly difficulties in doing screening themselves and a perception of health care that didn't match with screening. Information and organization were also important points to improve. The screening process was considered complex both by GPs and by patients. Numerous obstacles to colorectal screening, from both the physicians' and the patients' perspectives, were found. The major goal to improve mass screening may be to increase awareness and understanding of both physicians and patients regarding this process.

Obstacle avoidance handling and mixed integer predictive control for space robots

NASA Astrophysics Data System (ADS)

Zong, Lijun; Luo, Jianjun; Wang, Mingming; Yuan, Jianping

2018-04-01

This paper presents a novel obstacle avoidance constraint and a mixed integer predictive control (MIPC) method for space robots avoiding obstacles and satisfying physical limits during performing tasks. Firstly, a novel kind of obstacle avoidance constraint of space robots, which needs the assumption that the manipulator links and the obstacles can be represented by convex bodies, is proposed by limiting the relative velocity between two closest points which are on the manipulator and the obstacle, respectively. Furthermore, the logical variables are introduced into the obstacle avoidance constraint, which have realized the constraint form is automatically changed to satisfy different obstacle avoidance requirements in different distance intervals between the space robot and the obstacle. Afterwards, the obstacle avoidance constraint and other system physical limits, such as joint angle ranges, the amplitude boundaries of joint velocities and joint torques, are described as inequality constraints of a quadratic programming (QP) problem by using the model predictive control (MPC) method. To guarantee the feasibility of the obtained multi-constraint QP problem, the constraints are treated as soft constraints and assigned levels of priority based on the propositional logic theory, which can realize that the constraints with lower priorities are always firstly violated to recover the feasibility of the QP problem. Since the logical variables have been introduced, the optimization problem including obstacle avoidance and system physical limits as prioritized inequality constraints is termed as MIPC method of space robots, and its computational complexity as well as possible strategies for reducing calculation amount are analyzed. Simulations of the space robot unfolding its manipulator and tracking the end-effector's desired trajectories with the existence of obstacles and physical limits are presented to demonstrate the effectiveness of the proposed obstacle avoidance strategy and MIPC control method of space robots.

Laser development for optimal helicopter obstacle warning system LADAR performance

NASA Astrophysics Data System (ADS)

Yaniv, A.; Krupkin, V.; Abitbol, A.; Stern, J.; Lurie, E.; German, A.; Solomonovich, S.; Lubashitz, B.; Harel, Y.; Engart, S.; Shimoni, Y.; Hezy, S.; Biltz, S.; Kaminetsky, E.; Goldberg, A.; Chocron, J.; Zuntz, N.; Zajdman, A.

2005-04-01

Low lying obstacles present immediate danger to both military and civilian helicopters performing low-altitude flight missions. A LADAR obstacle detection system is the natural solution for enhancing helicopter safety and improving the pilot situation awareness. Elop is currently developing an advanced Surveillance and Warning Obstacle Ranging and Display (SWORD) system for the Israeli Air Force. Several key factors and new concepts have contributed to system optimization. These include an adaptive FOV, data memorization, autonomous obstacle detection and warning algorithms and the use of an agile laser transmitter. In the present work we describe the laser design and performance and discuss some of the experimental results. Our eye-safe laser is characterized by its pulse energy, repetition rate and pulse length agility. By dynamically controlling these parameters, we are able to locally optimize the system"s obstacle detection range and scan density in accordance with the helicopter instantaneous maneuver.

Critical Care Nurses' Perceptions of End-of-Life Care Obstacles: Comparative 17-Year Data.

PubMed

Beckstrand, Renea L; Lamoreaux, Nicole; Luthy, Karlen E; Macintosh, Janelle L B

Nurses working in intensive care units (ICUs) frequently care for patients and their families at the end of life (EOL). Providing high-quality EOL care is important for both patients and families, yet ICU nurses face many obstacles that hinder EOL care. Researchers have identified various ICU nurse-perceived obstacles, but no studies have been found addressing the progress that has been made for the last 17 years. The aims of this study were to determine the most common and current obstacles in EOL care as perceived by ICU nurses and then to evaluate whether meaningful changes have occurred since data were first gathered in 1998. A quantitative-qualitative mixed methods design was used. A random, geographically dispersed sample of 2000 members of the American Association of Critical-Care Nurses was surveyed. Five obstacle items increased in mean score and rank as compared with 1999 data including (1) family not understanding what the phrase "lifesaving measures" really means, (2) providing lifesaving measures at families' requests despite patient's advance directive listing no such care, (3) family not accepting patient's poor prognosis, (4) family members fighting about the use of life support, and (5) not enough time to provide EOL care because the nurse is consumed with lifesaving measures attempting to save the patient's life. Five obstacle items decreased in mean score and rank compared with 1999 data including (1) physicians differing in opinion about care of the patient, (2) family and friends who continually call the nurse rather than calling the designated family member, (3) physicians who are evasive and avoid families, (4) nurses having to deal with angry families, and (5) nurses not knowing their patient's wishes regarding continuing with tests and treatments. Obstacles in EOL care, as perceived by critical care nurses, still exist. Family-related obstacles have increased over time. Obstacles related to families may not be easily overcome as each family, dealing with a dying family member in an ICU, likely has not previously experienced a similar situation. On the basis of the current top 5 obstacles, recommendations for possible areas of focus include (1) improved health literacy assessment of families followed by earlier directed, appropriate, and specific EOL information; (2) improved physician/team communication; and (3) ensuring patients' wishes are followed as written. In general, patient- and family-centered care using clear and open EOL communication regarding wishes and desires between patients and families, their physicians, and nurses will help decrease common obstacles, thus improving the quality of EOL care provided to dying patients and families.

Death and injury in aerial spraying: pre-crash, crash, and post-crash prevention strategies.

PubMed

Richter, E D; Gordon, M; Halamish, M; Gribetz, B

1981-01-01

To prevent crash-related death and injury among spray pilots, a program including pre-crash, crash and post-crash stages of intervention for aircraft, physical environment, and pilots and ground crews was proposed in accordance with a matrix of options derived from road crash epidemiology. In addition to the dangers of fixed obstacles, low-altitude runs, and heavy work schedules, work hazards included combined exposures to noise, vibration, G forces, heat stress, pesticides, and dehydration. Together, these exposures were believed to have produced slight, but crucial decreases in pilot performance, alertness and skill. For aircraft, the major pre-crash measure was cockpit air cooling, with filter technologies to prevent in-flight pesticide exposure. Crash and post-crash design changes to reduce energy transfers to the pilot's body (thermal, kinetic) were the most important recommendations, because absolute prevention of the crash event was unlikely. For the environment, pre-crash recommendations included marking fixed obstacles, such as power and telephone lines, but preferably their elimination. Other measures included drainage pits with sodium hydroxide points to neutralize parathion and prevent dispersion of parathion-containing mists. Pilot pre-crash measures (more fluid intake, biological monitoring--EMG, urinary alkyl phosphate, cholinesterase testing) required special organizational arrangements. Systematic application of options from the foregoing matrix suggest that the high risk of death and injury from aerial spraying is unnecessary.

Defective support network: a major obstacle to coping for patients with heart failure: a qualitative study

PubMed Central

Shahrbabaki, Parvin Mangolian; Nouhi, Esmat; Kazemi, Majid; Ahmadi, Fazlollah

2016-01-01

Background Heart failure as a chronic disease poses many challenges for a patient in his or her everyday life. Support in various aspects of life positively affects coping strategies and influences the well-being and health outcomes of heart failure patients. Inadequate support may lead to a worsening of symptoms, increased hospital readmissions, psychological disorders, and a reduced quality of life. Objective This study explored obstacles to coping related to support for heart failure patients as viewed by the patients themselves and their family members and caregivers. Design This qualitative study was conducted using content analysis. The 20 Iranian participants included 11 patients with heart failure, three cardiologists, three nurses, and three family members of heart failure patients selected through purposive sampling. Data were collected through semi-structured interviews and analyzed using the Lundman and Graneheim qualitative content analysis method. Results During data analysis, ‘defective support network’ developed as the main theme along with four other categories of ‘inadequate family performance’, ‘inadequate support by the healthcare team’, ‘distorted societal social support’, and ‘inadequate welfare support’. Conclusion The findings of the current study can assist health authorities and planners in identifying the needs of patients with heart failure so as to focus and plan on facilitating their coping as much as possible by obviating the existing obstacles. PMID:27041539

The awareness and attitudes of students of one indian dental school toward information technology and its use to improve patient care.

PubMed

Jathanna, Vinod R; Jathanna, Ramya V; Jathanna, Roopalekha

2014-01-01

Many obstacles need to be overcome if digital and electronic technologies are to be fully integrated in the operation of dental clinics in some countries. These obstacles may be physical, technical, or psychosocial barriers in the form of perceptions and attitudes related to software incompatibilities, patient privacy, and interference with the patient-practitioner relationship. The objectives of the study are to assess the perceptions of Indian dental students of one school toward the usefulness of digital technologies in improving dental practice; their willingness to use digital and electronic technologies; the perceived obstacles to the use of digital and electronic technologies in dental care setups; and their attitudes toward Internet privacy issues. The study population consisted of 186 final year undergraduate dental students from the A. B. Shetty Memorial institute of Dental Sciences, Rajiv Gandhi University of Health Sciences, Mangalore, India. Survey data were analyzed descriptively . Most students indicated that information technology enhances patient satisfaction, the quality of dental record, diagnosis, treatment planning, and doctor-doctor communication. Cost of equipment and need for technical training were regarded as major obstacles by substantial proportions of respondents. Most dental students at our school feel that the information technology will support their decision making in diagnoses and devising effective treatment plans, which in turn increase patient satisfaction and quality of care. Students also perceived that lack of technical knowledge and the high cost of implementation are major barriers to developing information technology in India.

Political and legal implications of developing and operating a satellite power system

NASA Technical Reports Server (NTRS)

Hazelrigg, G. A., Jr.

1977-01-01

A number of political and legal implications of developing and operating a satellite power system (SPS) are identified and studied in this report. These include the vulnerability of SPS to actions of adversaries, communications impacts, the legality of an SPS in orbit including on-orbit military protection, alleviation of political concerns about deployment and operation of SPS, programmatic planning for SPS and the interaction of SPS with federal regulatory agencies and major departments. In comparing SPS to terrestrial power stations, it is seen that the political problems are neither clearly larger nor clearly smaller--they are clearly different and they are international in nature. If SPS is to become a reality these problems must be dealt with. Five major issues are identified. These must be resolved in order to obtain international acceptance of SPS. However, this study has found no insurmountable obstacles that would clearly prohibit the deployment, operation and protection of an SPS fleet.

A Monocular Vision Sensor-Based Obstacle Detection Algorithm for Autonomous Robots.

PubMed

Lee, Tae-Jae; Yi, Dong-Hoon; Cho, Dong-Il Dan

2016-03-01

This paper presents a monocular vision sensor-based obstacle detection algorithm for autonomous robots. Each individual image pixel at the bottom region of interest is labeled as belonging either to an obstacle or the floor. While conventional methods depend on point tracking for geometric cues for obstacle detection, the proposed algorithm uses the inverse perspective mapping (IPM) method. This method is much more advantageous when the camera is not high off the floor, which makes point tracking near the floor difficult. Markov random field-based obstacle segmentation is then performed using the IPM results and a floor appearance model. Next, the shortest distance between the robot and the obstacle is calculated. The algorithm is tested by applying it to 70 datasets, 20 of which include nonobstacle images where considerable changes in floor appearance occur. The obstacle segmentation accuracies and the distance estimation error are quantitatively analyzed. For obstacle datasets, the segmentation precision and the average distance estimation error of the proposed method are 81.4% and 1.6 cm, respectively, whereas those for a conventional method are 57.5% and 9.9 cm, respectively. For nonobstacle datasets, the proposed method gives 0.0% false positive rates, while the conventional method gives 17.6%.

Virtual Reality-Based Training to Improve Obstacle-Crossing Performance and Dynamic Balance in Patients With Parkinson's Disease.

PubMed

Liao, Ying-Yi; Yang, Yea-Ru; Cheng, Shih-Jung; Wu, Yih-Ru; Fuh, Jong-Ling; Wang, Ray-Yau

2015-08-01

Obstacle crossing is a balance-challenging task and can cause falls in people with Parkinson's disease (PD). However, programs for people with PD that effectively target obstacle crossing and dynamic balance have not been established. To examine the effects of virtual reality-based exercise on obstacle crossing performance and dynamic balance in participants with PD. Thirty-six participants with a diagnosis of PD (Hoehn and Yahr score ranging 1 to 3) were randomly assigned to one of three groups. In the exercise groups, participants received virtual reality-based Wii Fit exercise (VRWii group) or traditional exercise (TE group) for 45 minutes, followed by 15 minutes of treadmill training in each session for a total of 12 sessions over 6 weeks. Participants in the control group received no structured exercise program. Primary outcomes included obstacle crossing performance (crossing velocity, stride length, and vertical toe obstacle clearance) and dynamic balance (maximal excursion, movement velocity, and directional control measured by the limits-of-stability test). Secondary outcomes included sensory organization test (SOT), Parkinson's Disease Questionnaire (PDQ39), fall efficacy scale (FES-I), and timed up and go test (TUG). All outcomes were assessed at baseline, after training, and at 1-month follow-up. The VRWii group showed greater improvement in obstacle crossing velocity, crossing stride length, dynamic balance, SOT, TUG, FES-I, and PDQ39 than the control group. VRWii training also resulted in greater improvement in movement velocity of limits-of-stability test than TE training. VRWii training significantly improved obstacle crossing performance and dynamic balance, supporting implementation of VRWii training in participants with PD. © The Author(s) 2014.

Neuroepigenomics: Resources, Obstacles, and Opportunities

PubMed Central

Satterlee, John S.; Beckel-Mitchener, Andrea; Little, Roger; Procaccini, Dena; Rutter, Joni L.; Lossie, Amy C.

2014-01-01

Long-lived post-mitotic cells, such as the majority of human neurons, must respond effectively to ongoing changes in neuronal stimulation or microenvironmental cues through transcriptional and epigenomic regulation of gene expression. The role of epigenomic regulation in neuronal function is of fundamental interest to the neuroscience community, as these types of studies have transformed our understanding of gene regulation in post-mitotic cells. This perspective article highlights many of the resources available to researchers interested in neuroepigenomic investigations and discusses some of the current obstacles and opportunities in neuroepigenomics. PMID:25722961

Gender-Sensitive Education for a Better World. Background Document.

ERIC Educational Resources Information Center

Aksornkool, Namtip

Economic restructuring has severely affected the education of girls, particularly in the poorest and least developed countries where poverty is the major obstacle to education. Girls still constitute the majority of children not enrolled in school, and illiteracy among women remains one of the biggest challenges for the 21st century. Deep-rooted…

Forest Restoration in China: Advances, Obstacles, and Perspectives

Treesearch

Hai Ren; Hongfang Lu; Jun Wang; Nan Liu; Qinfeng Guo

2012-01-01

Because of the prolonged history of disturbance caused by intense human activities, restoration in China has been a major task facing many ecologists and land managers. There are six major forest types in China: cold temperate coniferous forest, temperate coniferous and broad-leaved mixed forest, warm temperate deciduous broad-leaved forest, subtropical evergreen broad...

Examining Peer Language Use and Investment in a Distinct North American Immersion Context

ERIC Educational Resources Information Center

Ballinger, Susan

2017-01-01

Previous studies have shown that immersion students tend to speak the majority language during peer interactions, regardless of the language of instruction or their dominant language. Researchers have argued that the societal status of the majority language presents an obstacle to providing equitable support for both languages of instruction. To…

Dynamic clearance measure to evaluate locomotor and perceptuo-motor strategies used for obstacle circumvention in a virtual environment.

PubMed

Darekar, Anuja; Lamontagne, Anouk; Fung, Joyce

2015-04-01

Circumvention around an obstacle entails a dynamic interaction with the obstacle to maintain a safe clearance. We used a novel mathematical interpolation method based on the modified Shepard's method of Inverse Distance Weighting to compute dynamic clearance that reflected this interaction as well as minimal clearance. This proof-of-principle study included seven young healthy, four post-stroke and four healthy age-matched individuals. A virtual environment designed to assess obstacle circumvention was used to administer a locomotor (walking) and a perceptuo-motor (navigation with a joystick) task. In both tasks, participants were asked to navigate towards a target while avoiding collision with a moving obstacle that approached from either head-on, or 30° left or right. Among young individuals, dynamic clearance did not differ significantly between obstacle approach directions in both tasks. Post-stroke individuals maintained larger and smaller dynamic clearance during the locomotor and the perceptuo-motor task respectively as compared to age-matched controls. Dynamic clearance was larger than minimal distance from the obstacle irrespective of the group, task and obstacle approach direction. Also, in contrast to minimal distance, dynamic clearance can respond differently to different avoidance behaviors. Such a measure can be beneficial in contrasting obstacle avoidance behaviors in different populations with mobility problems. Copyright © 2015 Elsevier B.V. All rights reserved.

Participation in the Mars data analysis program: Global and regional studies of wind-indicators on the surface of Mars

NASA Technical Reports Server (NTRS)

Veverka, J.; Thomas, P.

1984-01-01

Global and regional patterns on Mars were inferred from surface aeolian features, such as wind streaks and dune deposits, which were visible in Viking Orbiter images. Precise measurements of the dimensions of topographic obstacles, i.e., craters, hills, ridges, on Mars as well as their associated wind streaks were used to determine the aerodynamic shape of an obstacle affects near surface airflow. A classification of Martian wind streaks was developed on the basis of albedo contrast and the presence or absence of either topographic obstacles or sediment deposits at the point of origin of the wind streaks. It was concluded that local meteorological conditions, such as the stability of the atmospheric boundary layer, play a major role in determining why some Martian craters produce depositional wind streaks while others produce erosional ones.

Vision and agility training in community dwelling older adults: incorporating visual training into programs for fall prevention.

PubMed

Reed-Jones, Rebecca J; Dorgo, Sandor; Hitchings, Maija K; Bader, Julia O

2012-04-01

This study aimed to examine the effect of visual training on obstacle course performance of independent community dwelling older adults. Agility is the ability to rapidly alter ongoing motor patterns, an important aspect of mobility which is required in obstacle avoidance. However, visual information is also a critical factor in successful obstacle avoidance. We compared obstacle course performance of a group that trained in visually driven body movements and agility drills, to a group that trained only in agility drills. We also included a control group that followed the American College of Sports Medicine exercise recommendations for older adults. Significant gains in fitness, mobility and power were observed across all training groups. Obstacle course performance results revealed that visual training had the greatest improvement on obstacle course performance (22%) following a 12 week training program. These results suggest that visual training may be an important consideration for fall prevention programs. Copyright © 2011 Elsevier B.V. All rights reserved.

Analysis of the obstacles related to treatment entry, adherence and drop-out among alcoholic patients.

PubMed

Fonsi Elbreder, Márcia; Carvalho De Humerez, Dorisdaia; Laranjeira, Ronaldo

2009-01-01

Alcoholism is a complex syndrome involving social, psychological and individual factors in addition to a series of obstacles regarding treatment entry, adherence, and drop-out. These obstacles contribute negatively to both clinical evolution and prognosis of the patients, affecting their quality of life and raising the social costs. This is a bibliographical study in which we address this theme as well as other experiences observed in our daily practice in the Alcohol and Drug Research Unit (UNIAD) based at the Federal University of São Paulo (UNIFESP). The analysis of the obstacles related to treatment entry, attendance, and drop-out among alcoholic patients shows that systemic, social, cultural, and individual factors are all involved, including the structural ones. Women have more obstacles compared to men, and what is thought to be a barrier to one patient may be a factor motivating another patient to search for help. We conclude that several factors at different levels exist that prevent the patient from overcoming these treatment obstacles.

Implementing and using quality measures for children's health care: perspectives on the state of the practice.

PubMed

Shaller, Dale

2004-01-01

The objective of this study was to identify issues, obstacles, and priorities related to implementing and using child health care quality measures from the perspectives of 4 groups: 1) funders of quality-measurement development and implementation; 2) developers of quality measures; 3) users of quality measures (including Medicaid and the State Children's Health Insurance Program, employer coalitions, and consumer groups); and 4) health plans and providers (in their role as both subjects and users of quality measures). A series of semistructured interviews was conducted with approximately 40 opinion leaders drawn from these 4 groups. The interviews were conducted by telephone between September and December of 2001. Major topic areas covered in the interviews were similar across the groups. Topic areas included 1) strategic vision and/or objectives for funding, developing, or using quality measures for children's health care; 2) a brief summary of the specific quality measures funded, developed, or used; 3) issues and challenges facing funders and developers of measures; 4) major successes achieved; 5) obstacles to implementation and use of measures; and 6) priority needs for future funding. Leaders from all 4 groups acknowledge the importance of developing a robust set of quality measures that can serve multiple objectives and multiple audiences. Standardization of measures is viewed as a critical feature related to all objectives. An assessment of specific quality measures funded, developed, or used by strategic objective shows a high correlation between the uses intended by funders and developers and the actual applications of the various users. The most commonly cited measures across all groups are the Consumer Assessment of Health Plans Survey and Health Plan Employer Data and Information Set, followed by the Child and Adolescent Health Measurement Initiative and special topic studies to support quality-improvement applications (eg, asthma, diabetes, etc). The major issues and challenges cited in common among funders and developers are 1) the lack of trained capacity in the field to conduct needed research and development, and 2) the difficulty in generating sustained interest and support among funders because of the complexity of quality-measurement issues, competing funding priorities in the face of limited funds available to allocate, and the lack of clear and compelling evidence that quality measurement and improvement actually result in better outcomes for children. The 3 most common successes cited across all 4 groups are 1) the growing consensus and collaboration among diverse stakeholder groups involved in measurement development and implementation; 2) the increasing collection and use of specific measures; and 3) early documentation of tangible results in terms of improved quality of care. Specific measurement tools cited as successes by funders and developers include the Medicaid Health Plan Employer Data and Information Set, Consumer Assessment of Health Plans Survey, the Child and Adolescent Health Measurement Initiative, and Rand QA Tools. The most important obstacle reported across all groups is the lack of a strong and compelling "business case" that clearly demonstrates the benefits of quality measurement relative to the costs of implementation. Strongly related to this barrier is the cost of implementing and using measures without a sustainable source of financing as well as the absence of strong public awareness and political support for children's health care quality measurement. Another major barrier cited is the lack of coordination among funders, which prevents the field from developing a unified approach to addressing the numerous technical, political, and administrative issues also cited at length by the leaders interviewed. The 5 top needs for future funding identified across all 4 groups follow directly from the major obstacles that they reported: 1) develop the business case for children's health care quality measurement and improvement based on rigorous cost-bigorous cost-benefit analysis and documentation of quantifiable successes; 2) develop new measures to fill the gaps in critical areas (including adolescent health care, behavioral health, and chronic conditions) that can be applied at the hospital and ambulatory care provider levels; 3) invest in building needed research capacity, a trained pool of users of quality measures, and the capacity among providers to understand and use quality-improvement methods and tools; 4) invest in developing an information infrastructure that will support the efficient collection and use of measures for multiple purposes, including clinical practice, quality measurement, and quality improvement; and 5) develop increased public awareness and support for quality measurement based on improved strategies for communicating with consumers, purchasers, providers, and policy makers. Several implications are suggested by these perspectives for the future direction of quality measurement in children's health care. First, to meet the funding needs identified, many funders must improve coordination to reduce the noise and fragmentation generated by numerous competing or redundant activities. Improved coordination among funders will help assure maximum impact and the efficient use of scarce resources. Second, the importance attached to standardization of measures by both users and developers may conflict at times with the need for innovation and flexibility. Child health quality leaders will need to manage this tension between standardization and innovation to maintain an appropriate balance between the benefits of both. Finally, many of the obstacles identified are not unique to children's health care. Child health quality leaders will need to determine to what extent their efforts to overcome these obstacles can be successfully undertaken independently as opposed to in concert with groups concerned about other populations and sectors in the health care system.

Clogging and depinning of ballistic active matter systems in disordered media

NASA Astrophysics Data System (ADS)

Reichhardt, C.; Reichhardt, C. J. O.

2018-05-01

We numerically examine ballistic active disks driven through a random obstacle array. Formation of a pinned or clogged state occurs at much lower obstacle densities for the active disks than for passive disks. As a function of obstacle density, we identify several distinct phases including a depinned fluctuating cluster state, a pinned single-cluster or jammed state, a pinned multicluster state, a pinned gel state, and a pinned disordered state. At lower active disk densities, a drifting uniform liquid forms in the absence of obstacles, but when even a small number of obstacles are introduced, the disks organize into a pinned phase-separated cluster state in which clusters nucleate around the obstacles, similar to a wetting phenomenon. We examine how the depinning threshold changes as a function of disk or obstacle density and find a crossover from a collectively pinned cluster state to a disordered plastic depinning transition as a function of increasing obstacle density. We compare this to the behavior of nonballistic active particles and show that as we vary the activity from completely passive to completely ballistic, a clogged phase-separated state appears in both the active and passive limits, while for intermediate activity, a readily flowing liquid state appears and there is an optimal activity level that maximizes the flux through the sample.

A Monocular Vision Sensor-Based Obstacle Detection Algorithm for Autonomous Robots

PubMed Central

Lee, Tae-Jae; Yi, Dong-Hoon; Cho, Dong-Il “Dan”

2016-01-01

This paper presents a monocular vision sensor-based obstacle detection algorithm for autonomous robots. Each individual image pixel at the bottom region of interest is labeled as belonging either to an obstacle or the floor. While conventional methods depend on point tracking for geometric cues for obstacle detection, the proposed algorithm uses the inverse perspective mapping (IPM) method. This method is much more advantageous when the camera is not high off the floor, which makes point tracking near the floor difficult. Markov random field-based obstacle segmentation is then performed using the IPM results and a floor appearance model. Next, the shortest distance between the robot and the obstacle is calculated. The algorithm is tested by applying it to 70 datasets, 20 of which include nonobstacle images where considerable changes in floor appearance occur. The obstacle segmentation accuracies and the distance estimation error are quantitatively analyzed. For obstacle datasets, the segmentation precision and the average distance estimation error of the proposed method are 81.4% and 1.6 cm, respectively, whereas those for a conventional method are 57.5% and 9.9 cm, respectively. For nonobstacle datasets, the proposed method gives 0.0% false positive rates, while the conventional method gives 17.6%. PMID:26938540

Accepting, understanding, teaching, and learning (human) evolution: Obstacles and opportunities.

PubMed

Pobiner, Briana

2016-01-01

Questions about our origin as a species are universal and compelling. Evolution-and in particular human evolution-is a subject that generates intense interest across the world, evidenced by the fact that fossil and DNA discoveries grace the covers of major science journals and magazines as well as other popular print and online media. However, virtually all national polls indicate that the majority of Americans strongly reject biological evolution as a fact-based, well-tested, and robust understanding of the history of life. In the popular mind, no topic in all of science is more contentious or polarizing than evolution and media sources often only serve to magnify this polarization by covering challenges to the teaching of evolution. In the realm of teaching, debates about evolution have shaped textbooks, curricula, standards, and policy. Challenges to accepting and understanding evolution include mistrust and denial of science, cognitive obstacles and misconceptions, language and terminology, and a religious worldview, among others. Teachers, who are on the front lines of these challenges, must be armed with the tools and techniques to teach evolution in formal education settings across grades K-16 in a straightforward, thorough, and sensitive way. Despite the potentially controversial topic of human evolution, growing research is demonstrating that a pedagogical focus on human examples is an effective and engaging way to teach core concepts of evolutionary biology. © 2016 Wiley Periodicals, Inc.

Obstacle avoidance locomotor tasks: adaptation, memory and skill transfer.

PubMed

Kloter, Evelyne; Dietz, Volker

2012-05-01

The aim of this study was to explore the neural basis of adaptation, memory and skill transfer during human stepping over obstacles. Whilst walking on a treadmill, subjects had to perform uni- and bilateral obstacle steps. Acoustic feedback information about foot clearance was provided. Non-noxious electrical stimuli were applied to the right tibial nerve during the mid-stance phase of the right leg, i.e. 'prior' to the right or 'during' the left leg swing over the obstacle. The electromyogram (EMG) responses evoked by these stimuli in arm and leg muscles are known to reflect the neural coordination during normal and obstacle steps. The leading and trailing legs rapidly adapted foot clearance during obstacle steps with small further changes when the same obstacle condition was repeated. This adaptation was associated with a corresponding decrease in arm and leg muscle reflex EMG responses. Arm (but not leg) muscle EMG responses were greater when the stimulus was applied 'during' obstacle crossing by the left leg leading compared with stimulation 'prior' to right leg swing over the obstacle. A corresponding difference existed in arm muscle background EMG. The results indicate that, firstly, the somatosensory information gained by the performance and adaptation of uni- and bilateral obstacle stepping becomes transferred to the trailing leg in a context-specific manner. Secondly, EMG activity in arm and leg muscles parallels biomechanical adaptation of foot clearance. Thirdly, a consistently high EMG activity in the arm muscles during swing over the obstacle is required for equilibrium control. Thus, such a precision locomotor task is achieved by a context-specific, coordinated activation of arm and leg muscles for performance and equilibrium control that includes adaptation, memory and skill transfer. © 2012 The Authors. European Journal of Neuroscience © 2012 Federation of European Neuroscience Societies and Blackwell Publishing Ltd.

[Spatial-temporal pattern and obstacle factors of cultivated land ecological security in major grain producing areas of northeast China: a case study in Jilin Province].

PubMed

Zhao, Hong-Bo; Ma, Yan-Ji

2014-02-01

According to the cultivated land ecological security in major grain production areas of Northeast China, this paper selected 48 counties of Jilin Province as the research object. Based on the PSR-EES conceptual framework model, an evaluation index system of cultivated land ecological security was built. By using the improved TOPSIS, Markov chains, GIS spatial analysis and obstacle degree models, the spatial-temporal pattern of cultivated land ecological security and the obstacle factors were analyzed from 1995 to 2011 in Jilin Province. The results indicated that, the composite index of cultivated land ecological security appeared in a rising trend in Jilin Province from 1995 to 2011, and the cultivated land ecological security level changed from being sensitive to being general. There was a pattern of 'Club Convergence' in cultivated land ecological security level in each county and the spatial discrepancy tended to become larger. The 'Polarization' trend of cultivated land ecological security level was obvious. The distributions of sensitive level and critical security level with ribbon patterns tended to be dispersed, the general security level and relative security levels concentrated, and the distributions of security level scattered. The unstable trend of cultivated land ecological security level was more and more obvious. The main obstacle factors that affected the cultivated land ecological security level in Jilin Province were rural net income per capita, economic density, the proportion of environmental protection investment in GDP, degree of machinery cultivation and the comprehensive utilization rate of industrial solid wastes.

Obstetric fistulae in West Africa: patient perspectives.

PubMed

Nathan, Lisa M; Rochat, Charles H; Grigorescu, Bogdan; Banks, Erika

2009-05-01

The objective of this study is to gain insight into the nature of obstetric fistulae in Africa through patient perspectives. At l'Hôpital Saint Jean de Dieu in Tanguieta, Benin, 37 fistula patients underwent structured interviews about fistula cause, obstacles to medical care, prevention, and reintegration by 2 physicians via interpreters. The majority of participants (43%) thought their fistulae were a result of trauma from the operative delivery. Lack of financial resources (49%) was the most commonly reported obstacle to care, and prenatal care (38%) was most frequently reported as an intervention that may prevent obstetric fistulae. The majority (49%) of the participants requested no further reintegration assistance aside from surgery. Accessible emergency obstetric care is necessary to decrease the burden of obstetric fistulae in Africa. This may be accomplished through increased and improved health care facilities and education of providers and patients.

Improvement of mechanical behaviors of a superlight Mg-Li base alloy by duplex phases and fine precipitates

DOE PAGES

Zou, Yun; Zhang, Lehao; Li, Yang; ...

2017-12-06

Limitations of strength and formability are the major obstacles to the industrial application of magnesium alloys. Here, we demonstrate, by producing the duplex phases and fine intermetallic particles in composition-optimized superlight Mg-Li-Al alloys, a unique approach to simultaneously improve the comprehensive mechanical properties (a strength-ductility balance). In conclusion, the phase components and microstructures, including the size, morphology, and distribution of precipitated-intermetallic particles can be optimized by tuning the Li content, which strongly influences the work-hardening behavior and tension-compression yield asymmetry.

[Perspectives and challenges of malaria vaccine. Why we must do more].

PubMed

Leroy, Odile

2007-10-01

During the last 10 years the development of a malaria vaccine has attracted an increasing amount of attention both from the political sector and from financial investors. This has led to a number of major scientific and technological advances, but much remains to be done. Numerous potential target antigens are under investigation, and most research is focusing on a subunit vaccine. Irradiated attenuated sporozoites are also a promising approach, even if major technological and regulatory challenges remain to be overcome. Barriers to vaccine development include an inadequate understanding of certain aspects of host-parasite biology and protective immune responses. Other challenges are to increase the antigenicity of some antigens, and to optimize the quality of the immune response. However, research funding remains the main obstacle.

Women’s orgasm obstacles: A qualitative study

PubMed Central

Nekoolaltak, Maryam; Keshavarz, Zohreh; Simbar, Masoumeh; Nazari, Ali Mohammad; Baghestani, Ahmad Reza

2017-01-01

Background: Woman’s orgasm plays a vital role in sexual compatibility and marital satisfaction. Orgasm in women is a learnable phenomenon that is influenced by several factors. Objective: The aim of this study is exploring obstacles to orgasm in Iranian married women. Materials and Methods: This qualitative study with directed content analysis approach was conducted in 2015-2016, on 20 Iranian married women who were individually interviewed at two medical clinics in Tehran, Iran. Results: Orgasm obstacles were explored in one category, 4 subcategories, and 25 codes. The main category was “Multidimensionality of women’s orgasm obstacles”. Subcategories and some codes included: Physical obstacles (wife’s or husband’s boredom, vaginal infection, insufficient vaginal lubrication), psychological obstacles (lack of sexual knowledge, shame, lack of concentration on sex due to household and children problems), relational obstacles (husband’s hurry, having a dispute and annoyance with spouse) and contextual obstacles (Irregular sleep hours, lack of privacy and inability to separate children’s bedroom from their parents, lack of peace at home). Conclusion: For prevention or treatment of female orgasm disorders, attention to physical factors is not enough. Obtaining a comprehensive history about physical, psychological, relational and contextual dimensions of woman’s life is necessary. PMID:29082366

Using OER as a Tool for Agribusiness Management Training for Hard-to-Reach Rural Farmer Populations

ERIC Educational Resources Information Center

Muniafu, Maina; Wambalaba, Francis; Wanyama, Walter; Nduati, Gidraph; Ndirangu, Dalton

2013-01-01

Agriculture is the mainstay of Kenya's economy and contributes significantly to the gross domestic product. A great majority of this contribution comes from smallholder farmers who paradoxically face numerous obstacles ranging from a lack of support structures to poor policies and inadequate resources. A major challenge is assisting these farmers…

Engineering functional inorganic-organic hybrid systems: advances in siRNA therapeutics.

PubMed

Shen, Jianliang; Zhang, Wei; Qi, Ruogu; Mao, Zong-Wan; Shen, Haifa

2018-03-21

Cancer treatment still faces a lot of obstacles such as tumor heterogeneity, drug resistance and systemic toxicities. Beyond the traditional treatment modalities, exploitation of RNA interference (RNAi) as an emerging approach has immense potential for the treatment of various gene-caused diseases including cancer. The last decade has witnessed enormous research and achievements focused on RNAi biotechnology. However, delivery of small interference RNA (siRNA) remains a key challenge in the development of clinical RNAi therapeutics. Indeed, functional nanomaterials play an important role in siRNA delivery, which could overcome a wide range of sequential physiological and biological obstacles. Nanomaterial-formulated siRNA systems have potential applications in protection of siRNA from degradation, improving the accumulation in the target tissues, enhancing the siRNA therapy and reducing the side effects. In this review, we explore and summarize the role of functional inorganic-organic hybrid systems involved in the siRNA therapeutic advancements. Additionally, we gather the surface engineering strategies of hybrid systems to optimize for siRNA delivery. Major progress in the field of inorganic-organic hybrid platforms including metallic/non-metallic cores modified with organic shells or further fabrication as the vectors for siRNA delivery is discussed to give credit to the interdisciplinary cooperation between chemistry, pharmacy, biology and medicine.

Obstacles to preventive care for individuals with disability: Implications for nurse practitioners.

PubMed

Marrocco, Anna; Krouse, Helene J

2017-05-01

Individuals with disabilities have been identified as a population with a significantly lower usage of preventive services. Nurse practitioners (NPs) provide a key access point in the healthcare delivery system for preventive services for vulnerable populations such as those with disabilities. It is essential to understand existing barriers that prohibit access to effective preventive care for this vulnerable population. Systematic search and review of Cumulative Index of Nursing and Allied Health Literature (CINAHL), Medline, PubMed, Google Scholar, and government reports and World Health Organizations reports. Twenty-six articles were included in the review. This literature review confirmed previous notions that people with disabilities are receiving much fewer preventive services than the general population. The studies reviewed identified four major barriers that contributed to the lack of preventive care. These barriers included physical environment and system, transportation, provider knowledge and attitude, and financial. Recognition of the obstacles that this subpopulation faces in accessing preventive care services is the first step to effectively remedying this problem. Preventive services have been identified as one of the cornerstones to improving health and quality of life. By understanding the circumstances that restrict those with disabilities from accessing preventive services, NPs can provide meaningful and effective solutions. ©2017 American Association of Nurse Practitioners.

Reliability Analysis of Time to Complete the Obstacle Course Portion of the Load Effects Assessment Program (LEAP)

DTIC Science & Technology

2016-10-25

TIME TO COMPLETE THE OBSTACLE COURSE PORTION OF THE LOAD EFFECTS ASSESSMENT PROGRAM (LEAP) by K. Blake Mitchell Jessica M. Batty Megan E...Approved OMB No. 0704-0188 Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for...2014 – June 2015 4. TITLE AND SUBTITLE RELIABILITY ANALYSIS OF TIME TO COMPLETE THE OBSTACLE COURSE PORTION OF THE LOAD EFFECTS ASSESSMENT PROGRAM

Assessing gait adaptability in people with a unilateral amputation on an instrumented treadmill with a projected visual context.

PubMed

Houdijk, Han; van Ooijen, Mariëlle W; Kraal, Jos J; Wiggerts, Henri O; Polomski, Wojtek; Janssen, Thomas W J; Roerdink, Melvyn

2012-11-01

Gait adaptability, including the ability to avoid obstacles and to take visually guided steps, is essential for safe movement through a cluttered world. This aspect of walking ability is important for regaining independent mobility but is difficult to assess in clinical practice. The objective of this study was to investigate the validity of an instrumented treadmill with obstacles and stepping targets projected on the belt's surface for assessing prosthetic gait adaptability. This was an observational study. A control group of people who were able bodied (n=12) and groups of people with transtibial (n=12) and transfemoral (n=12) amputations participated. Participants walked at a self-selected speed on an instrumented treadmill with projected visual obstacles and stepping targets. Gait adaptability was evaluated in terms of anticipatory and reactive obstacle avoidance performance (for obstacles presented 4 steps and 1 step ahead, respectively) and accuracy of stepping on regular and irregular patterns of stepping targets. In addition, several clinical tests were administered, including timed walking tests and reports of incidence of falls and fear of falling. Obstacle avoidance performance and stepping accuracy were significantly lower in the groups with amputations than in the control group. Anticipatory obstacle avoidance performance was moderately correlated with timed walking test scores. Reactive obstacle avoidance performance and stepping accuracy performance were not related to timed walking tests. Gait adaptability scores did not differ in groups stratified by incidence of falls or fear of falling. Because gait adaptability was affected by walking speed, differences in self-selected walking speed may have diminished differences in gait adaptability between groups. Gait adaptability can be validly assessed by use of an instrumented treadmill with a projected visual context. When walking speed is taken into account, this assessment provides unique, quantitative information about walking ability in people with a lower-limb amputation.

Obstacles to the implementation of the treat-to-target strategy for rheumatoid arthritis in clinical practice in Japan.

PubMed

Kaneko, Yuko; Koike, Takao; Oda, Hiromi; Yamamoto, Kazuhiko; Miyasaka, Nobuyuki; Harigai, Masayoshi; Yamanaka, Hisashi; Ishiguro, Naoki; Tanaka, Yoshiya; Takeuchi, Tsutomu

2015-01-01

To clarify the obstacles preventing the implementation of the treat-to-target (T2T) strategy for rheumatoid arthritis (RA) in clinical practice. A total of 301 rheumatologists in Japan completed a questionnaire. In the first section, participants were indirectly questioned on the implementation of basic components of T2T, and in the second section, participants were directly questioned on their level of agreement and application. Although nearly all participants set treatment targets for the majority of RA patients with moderate to high disease activity, the proportion who set clinical remission as their target was 59%, with only 45% of these using composite measures. The proportion of participants who monitored X-rays and Health Assessment Questionnaires for all their patients was 44% and 14%, respectively. The proportion of participants who did not discuss treatment strategies was 44%, with approximately half of these reasoning that this was due to a proportion of patients having a lack of understanding of the treatment strategy or inability to make decisions. When participants were directly questioned, there was a high level of agreement with the T2T recommendations. Although there was a high level of agreement with the T2T recommendations, major obstacles preventing its full implementation still remain.

Sex and age-level differences of walking time in preschool children on an obstacle frame

PubMed Central

2012-01-01

Background Stepping over an obstacle is a kind of compound movement that makes walking more difficult, especially for preschool children. This study examines sex and age-level differences in walking time in preschool children on an obstacle frame. Methods The participants included 324 healthy preschool children: four-year-old boys (51) and girls (51), five-year-old boys (50) and girls (60), and six-year-old boys (62) and girls (50). A 5 cm- or 10 cm-high obstacle (depth 11.5 cm, width 23.5 cm) was set at the halfway point of a 200 cm × 10 cm walking course. Results The participants walked to the end of the course and back as fast as possible under three conditions: no obstacle, low obstacle and high obstacle. Walking time showed age-level differences in all conditions, but there were no differences in sex. Age levels were divided into two groups, with one group within the first six months of their birthday, and the second group within the last six months of that year. Walking time for children in the first half of their fourth year was longer than that of the five- and six-year-old children. In addition, for children in the last half of their fourth year, walking time was longer than both sexes in the last half of their fifth and sixth years. The children in the latter half of their fifth year had a longer walking time in the high obstacle condition than those in the last half of their sixth year. In the four-year-old participants, walking time was shorter with no obstacles than with a high obstacle frame. Conclusions In the above data, obstacle course walking time does not show a gender difference, except that the four-year-old participants needed longer than the five- and six-year-old children. Setting the obstacle 10 cm high also produced a different walking time in the five- and six-year-old participants. The high obstacle step test (10 cm) best evaluated the dynamic balance of preschool children. PMID:22738328

Obstacle course runs: review of acquired injuries and illnesses at a series of Canadian events (RACE).

PubMed

Hawley, Alana; Mercuri, Mathew; Hogg, Kerstin; Hanel, Erich

2017-03-01

The growing popularity of obstacle course runs (OCRs) has led to significant concerns regarding their safety. The influx of injuries and illnesses in rural areas where OCRs are often held can impose a large burden on emergency medical services (EMS) and local EDs. Literature concerning the safety of these events is minimal and mostly consists of media reports. We sought to characterise the injury and illness profile of OCRs and the level of medical care required. This study analysed OCR events occurring in eight locations across Canada from May to August 2015 (total 45 285 participants). Data were extracted from event medical charts of patients presenting to the onsite medical team, including injury or illness type, onsite treatment and disposition. There were 557 race participants treated at eight OCR events (1.2% of all participants). There were 609 medical complaints in total. Three quarters of injuries were musculoskeletal in nature. Eighty-nine per cent returned to the event with no need for further medical care. The majority of treatments were completed with first aid and basic medical equipment. Eleven patients (2% of patients) required transfer to hospital by EMS for presentations including fracture, dislocation, head injury, chest pain, fall from height, and abdominal pain. We found that 1.2% of race participants presented to onsite medical services. The majority of complaints were minor and musculoskeletal in nature. Only 2% of those treated were transferred to hospital through EMS. This is consistent with other types of mass gathering events. 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/.

Deer repellent fails to protect pine seedlings

Treesearch

W. E. McQuilkin; S. Little

1952-01-01

In some parts of the Northeast, browsing by deer is one of the major obstacles to successful forest regeneration. Untold damage is done every year to farm crops, gardens, and ornamental plantings in the region as a whole.

The role of tragus on echolocating bat, Eptesicus fuscus

NASA Astrophysics Data System (ADS)

Chiu, Chen; Moss, Cynthia

2005-04-01

Echolocating bats produce ultrasonic vocal signals and utilize the returning echoes to detect, localize and track prey, and also to avoid obstacles. The pinna and tragus, two major components of the bats external ears, play important roles in filtering returning echoes. The tragus is generally believed to play a role in vertical sound localization. The purpose of this study is to further examine how manipulation of the tragus affects a free-flying bat's prey capture and obstacle avoidance behavior. The first part of this study involved a prey capture experiment, and the bat was trained to catch the tethered mealworms in a large room. The second experiment involved obstacle avoidance, and the bat's task was to fly through the largest opening from a horizontal wire array without touching the wires. In both experiments, the bat performed the tasks under three different conditions: with intact tragus, tragus-deflection and recovery from tragus-deflection. Significantly lower performance was observed in both experiments when tragi were glued down. However, the bat adjusted quickly and returned to baseline performance a few days after the manipulation. The results suggest that tragus-deflection does have effects on both the prey capture and obstacle avoidance behavior. [Work supported by NSF.

Obstacle detection and avoiding of quadcopter

NASA Astrophysics Data System (ADS)

Wang, Dizhong; Lin, Jiajian

2017-10-01

Recent years, the flight control technology over quadcopter has been boosted vigorously and acquired the comprehensive application in a variety of industries. However, it is prominent for there to be problems existed in the stable and secure flight with the development of its autonomous flight. Through comparing with the characteristics of ultrasonic ranging and laser Time-of-Flight(abbreviated to ToF) distance as well as vision measurement and its related sensors, the obstacle detection and identification sensors need to be installed in order to effectively enhance the safety flying for aircraft, which is essential for avoiding the dangers around the surroundings. That the major sensors applied to objects perception at present are distance measuring instruments which based on the principle and application of non-contact detection technology . Prior to acknowledging the general principles of flight and obstacle avoiding, the aerodynamics modeling of the quadcopter and its object detection means has been initially determined on this paper. Based on such premise, this article emphasized on describing and analyzing the research on obstacle avoiding technology and its application status, and making an expectation for the trend of its development after analyzing the primary existing problems concerning its accuracy object avoidance.

Passive detection of subpixel obstacles for flight safety

NASA Astrophysics Data System (ADS)

Nixon, Matthew D.; Loveland, Rohan C.

2001-12-01

Military aircraft fly below 100 ft. above ground level in support of their missions. These aircraft include fixed and rotary wing and may be manned or unmanned. Flying at these low altitudes presents a safety hazard to the aircrew and aircraft, due to the occurrences of obstacles within the aircraft's flight path. The pilot must rely on eyesight and in some cases, infrared sensors to see obstacles. Many conditions can exacerbate visibility creating a situation in which obstacles are essentially invisible, creating a safety hazard, even to an alerted aircrew. Numerous catastrophic accidents have occurred in which aircraft have collided with undetected obstacles. Accidents of this type continue to be a problem for low flying military and commercial aircraft. Unmanned Aerial Vehicles (UAVs) have the same problem, whether operating autonomously or under control of a ground operator. Boeing-SVS has designed a passive, small, low- cost (under $100k) gimbaled, infrared imaging based system with advanced obstacle detection algorithms. Obstacles are detected in the infrared band, and linear features are analyzed by innovative cellular automata based software. These algorithms perform detection and location of sub-pixel linear features. The detection of the obstacles is performed on a frame by frame basis, in real time. Processed images are presented to the aircrew on their display as color enhanced features. The system has been designed such that the detected obstacles are displayed to the aircrew in sufficient time to react and maneuver the aircraft to safety. A patent for this system is on file with the US patent office, and all material herein should be treated accordingly.

Access to Care for Multiple Sclerosis in Times of Economic Crisis in Greece – the HOPE II Study

PubMed Central

Souliotis, Kyriakos; Alexopoulou, Elena; Papageorgiou, Manto; Politi, Anastasia; Litsa, Panagiota; Contiades, Xenophon

2016-01-01

Background: While there is currently no cure for multiple sclerosis (MS), treatment with biologic disease-modifying drugs (bDMDs) can reduce the impact of the condition on the lives of patients. In Greece, the regulatory change in the distribution system of bDMDs, limited their administration through the designated pharmacies of the National Organization for Healthcare Services Provision (EOPYY) or the National Health System (ESY) hospitals, thus potentially impacting access to MS treatment. In this context, the aim of this paper was to assess the barriers to bDMDs, by recording MS patients’ experiences. Methods: A survey research was conducted between January and February 2014 in Athens and 5 other major Greek cities with the methods of personal and telephone interview. A structured questionnaire was used to elicit socio-economic and medical information, information related to obstacles in accessing bDMDs and medical treatment, from MS patients that visited EOPYY pharmacies during the study period. Results: During the last year 69% of 179 participants reported that the distribution system of bDMDs has improved. Thirteen percent of participants encountered problems in accessing their medication, and 16.9% of participants in accessing their physician, with the obstacles being more pronounced for non-Athens residents. Frequent obstacles to bDMDs were the distance from EOPYY pharmacies and difficulties in obtaining a diagnosis from an EOPYY/ESY physician, while obstacles to medical care were delays in appointment booking and travel difficulties. Conclusion: Even though the major weaknesses of the distribution system of bDMDs have improved, further amelioration of the system could be achieved through the home delivery of medicines to patients living in remote areas, and through the development of a national MS registry. PMID:26927393

The Case for High-Performance, Healthy Green Schools

ERIC Educational Resources Information Center

Carter, Leesa

2011-01-01

When trying to reach their sustainability goals, schools and school districts often run into obstacles, including financing, training, and implementation tools. Last fall, the U.S. Green Building Council-Georgia (USGBC-Georgia) launched its High Performance, Healthy Schools (HPHS) Program to help Georgia schools overcome those obstacles. By…

Anticipatory Postural Control of Stability during Gait Initiation Over Obstacles of Different Height and Distance Made Under Reaction-Time and Self-Initiated Instructions.

PubMed

Yiou, Eric; Artico, Romain; Teyssedre, Claudine A; Labaune, Ombeline; Fourcade, Paul

2016-01-01

Despite the abundant literature on obstacle crossing in humans, the question of how the central nervous system (CNS) controls postural stability during gait initiation with the goal to clear an obstacle remains unclear. Stabilizing features of gait initiation include anticipatory postural adjustments (APAs) and lateral swing foot placement. To answer the above question, 14 participants initiated gait as fast as possible in three conditions of obstacle height, three conditions of obstacle distance and one obstacle-free (control) condition. Each of these conditions was performed with two levels of temporal pressure: reaction-time (high-pressure) and self-initiated (low-pressure) movements. A mechanical model of the body falling laterally under the influence of gravity and submitted to an elastic restoring force is proposed to assess the effect of initial (foot-off) center-of-mass position and velocity (or "initial center-of-mass set") on the stability at foot-contact. Results showed that the anticipatory peak of mediolateral (ML) center-of-pressure shift, the initial ML center-of-mass velocity and the duration of the swing phase, of gait initiation increased with obstacle height, but not with obstacle distance. These results suggest that ML APAs are scaled with swing duration in order to maintain an equivalent stability across experimental conditions. This statement is strengthened by the results obtained with the mechanical model, which showed how stability would be degraded if there was no adaptation of the initial center-of-mass set to swing duration. The anteroposterior (AP) component of APAs varied also according to obstacle height and distance, but in an opposite way to the ML component. Indeed, results showed that the anticipatory peak of backward center-of-pressure shift and the initial forward center-of-mass set decreased with obstacle height, probably in order to limit the risk to trip over the obstacle, while the forward center-of-mass velocity at foot-off increased with obstacle distance, allowing a further step to be taken. These effects of obstacle height and distance were globally similar under low and high-temporal pressure. Collectively, these findings imply that the CNS is able to predict the potential instability elicited by the obstacle clearance and that it scales the spatiotemporal parameters of APAs accordingly.

Anticipatory Postural Control of Stability during Gait Initiation Over Obstacles of Different Height and Distance Made Under Reaction-Time and Self-Initiated Instructions

PubMed Central

Yiou, Eric; Artico, Romain; Teyssedre, Claudine A.; Labaune, Ombeline; Fourcade, Paul

2016-01-01

Despite the abundant literature on obstacle crossing in humans, the question of how the central nervous system (CNS) controls postural stability during gait initiation with the goal to clear an obstacle remains unclear. Stabilizing features of gait initiation include anticipatory postural adjustments (APAs) and lateral swing foot placement. To answer the above question, 14 participants initiated gait as fast as possible in three conditions of obstacle height, three conditions of obstacle distance and one obstacle-free (control) condition. Each of these conditions was performed with two levels of temporal pressure: reaction-time (high-pressure) and self-initiated (low-pressure) movements. A mechanical model of the body falling laterally under the influence of gravity and submitted to an elastic restoring force is proposed to assess the effect of initial (foot-off) center-of-mass position and velocity (or “initial center-of-mass set”) on the stability at foot-contact. Results showed that the anticipatory peak of mediolateral (ML) center-of-pressure shift, the initial ML center-of-mass velocity and the duration of the swing phase, of gait initiation increased with obstacle height, but not with obstacle distance. These results suggest that ML APAs are scaled with swing duration in order to maintain an equivalent stability across experimental conditions. This statement is strengthened by the results obtained with the mechanical model, which showed how stability would be degraded if there was no adaptation of the initial center-of-mass set to swing duration. The anteroposterior (AP) component of APAs varied also according to obstacle height and distance, but in an opposite way to the ML component. Indeed, results showed that the anticipatory peak of backward center-of-pressure shift and the initial forward center-of-mass set decreased with obstacle height, probably in order to limit the risk to trip over the obstacle, while the forward center-of-mass velocity at foot-off increased with obstacle distance, allowing a further step to be taken. These effects of obstacle height and distance were globally similar under low and high-temporal pressure. Collectively, these findings imply that the CNS is able to predict the potential instability elicited by the obstacle clearance and that it scales the spatiotemporal parameters of APAs accordingly. PMID:27656138

A Depth-Based Head-Mounted Visual Display to Aid Navigation in Partially Sighted Individuals

PubMed Central

Hicks, Stephen L.; Wilson, Iain; Muhammed, Louwai; Worsfold, John; Downes, Susan M.; Kennard, Christopher

2013-01-01

Independent navigation for blind individuals can be extremely difficult due to the inability to recognise and avoid obstacles. Assistive techniques such as white canes, guide dogs, and sensory substitution provide a degree of situational awareness by relying on touch or hearing but as yet there are no techniques that attempt to make use of any residual vision that the individual is likely to retain. Residual vision can restricted to the awareness of the orientation of a light source, and hence any information presented on a wearable display would have to limited and unambiguous. For improved situational awareness, i.e. for the detection of obstacles, displaying the size and position of nearby objects, rather than including finer surface details may be sufficient. To test whether a depth-based display could be used to navigate a small obstacle course, we built a real-time head-mounted display with a depth camera and software to detect the distance to nearby objects. Distance was represented as brightness on a low-resolution display positioned close to the eyes without the benefit focussing optics. A set of sighted participants were monitored as they learned to use this display to navigate the course. All were able to do so, and time and velocity rapidly improved with practise with no increase in the number of collisions. In a second experiment a cohort of severely sight-impaired individuals of varying aetiologies performed a search task using a similar low-resolution head-mounted display. The majority of participants were able to use the display to respond to objects in their central and peripheral fields at a similar rate to sighted controls. We conclude that the skill to use a depth-based display for obstacle avoidance can be rapidly acquired and the simplified nature of the display may appropriate for the development of an aid for sight-impaired individuals. PMID:23844067

High Order Accurate Algorithms for Shocks, Rapidly Changing Solutions and Multiscale Problems

DTIC Science & Technology

2014-11-13

for front propagation with obstacles, and homotopy method for steady states. Applications include high order simulations for 3D gaseous detonations ...obstacles, and homotopy method for steady states. Applications include high order simulations for 3D gaseous detonations , sound generation study via... detonation waves, Combustion and Flame, (02 2013): 0. doi: 10.1016/j.combustflame.2012.10.002 Yang Yang, Ishani Roy, Chi-Wang Shu, Li-Zhi Fang. THE

Design and Development of a Mobile Sensor Based the Blind Assistance Wayfinding System

NASA Astrophysics Data System (ADS)

Barati, F.; Delavar, M. R.

2015-12-01

The blind and visually impaired people are facing a number of challenges in their daily life. One of the major challenges is finding their way both indoor and outdoor. For this reason, routing and navigation independently, especially in urban areas are important for the blind. Most of the blind undertake route finding and navigation with the help of a guide. In addition, other tools such as a cane, guide dog or electronic aids are used by the blind. However, in some cases these aids are not efficient enough in a wayfinding around obstacles and dangerous areas for the blind. As a result, the need to develop effective methods as decision support using a non-visual media is leading to improve quality of life for the blind through their increased mobility and independence. In this study, we designed and implemented an outdoor mobile sensor-based wayfinding system for the blind. The objectives of this study are to guide the blind for the obstacle recognition and the design and implementation of a wayfinding and navigation mobile sensor system for them. In this study an ultrasonic sensor is used to detect obstacles and GPS is employed for positioning and navigation in the wayfinding. This type of ultrasonic sensor measures the interval between sending waves and receiving the echo signals with respect to the speed of sound in the environment to estimate the distance to the obstacles. In this study the coordinates and characteristics of all the obstacles in the study area are already stored in a GIS database. All of these obstacles were labeled on the map. The ultrasonic sensor designed and constructed in this study has the ability to detect the obstacles in a distance of 2cm to 400cm. The implementation and the results obtained from the interview of a number of blind persons who employed the sensor verified that the designed mobile sensor system for wayfinding was very satisfactory.

Cost-effective safety treatments for low-volume roads.

DOT National Transportation Integrated Search

2012-08-01

The majority of roadside safety guidance pertains to high-volume roads. Very little guidance exists to assist engineers in : treating common obstacles found alongside low-volume roads. In general, it is assumed that low traffic volumes can effectivel...

Evaluation of 3M(TM) Scotchlite linear delineation system : final report.

DOT National Transportation Integrated Search

2004-09-01

Major construction projects present many hazards for drivers to negotiate. Detours, lane shifts and confusing curves : present unique challenges to all drivers. At night, the difficulties in negotiating these obstacles are amplified due to : reduced ...

Phosphodiesterase inhibitors as a new generation of antiprotozoan drugs: exploiting the benefit of enzymes that are highly conserved between host and parasite

PubMed Central

Seebeck, Thomas; Sterk, Geert Jan; Ke, Hengming

2011-01-01

Protozoan infections remain a major unsolved medical problem in many parts of our world. A major obstacle to their treatment is the blatant lack of medication that is affordable, effective, safe and easy to administer. For some of these diseases, including human sleeping sickness, very few compounds are available, many of them old and all of them fraught with toxic side effects. We explore a new concept for developing new-generation antiprotozoan drugs that are based on phosphodiesterase (PDE) inhibitors. Such inhibitors are already used extensively in human pharmacology. Given the high degree of structural similarity between the human and the protozoan PDEs, the vast expertise available in the human field can now be applied to developing disease-specific PDE inhibitors as new antiprotozoan drugs. PMID:21859303

Obstacle Detection Algorithms for Aircraft Navigation: Performance Characterization of Obstacle Detection Algorithms for Aircraft Navigation

NASA Technical Reports Server (NTRS)

Kasturi, Rangachar; Camps, Octavia; Coraor, Lee

2000-01-01

The research reported here is a part of NASA's Synthetic Vision System (SVS) project for the development of a High Speed Civil Transport Aircraft (HSCT). One of the components of the SVS is a module for detection of potential obstacles in the aircraft's flight path by analyzing the images captured by an on-board camera in real-time. Design of such a module includes the selection and characterization of robust, reliable, and fast techniques and their implementation for execution in real-time. This report describes the results of our research in realizing such a design. It is organized into three parts. Part I. Data modeling and camera characterization; Part II. Algorithms for detecting airborne obstacles; and Part III. Real time implementation of obstacle detection algorithms on the Datacube MaxPCI architecture. A list of publications resulting from this grant as well as a list of relevant publications resulting from prior NASA grants on this topic are presented.

A nonlinear model predictive control formulation for obstacle avoidance in high-speed autonomous ground vehicles in unstructured environments

NASA Astrophysics Data System (ADS)

Liu, Jiechao; Jayakumar, Paramsothy; Stein, Jeffrey L.; Ersal, Tulga

2018-06-01

This paper presents a nonlinear model predictive control (MPC) formulation for obstacle avoidance in high-speed, large-size autono-mous ground vehicles (AGVs) with high centre of gravity (CoG) that operate in unstructured environments, such as military vehicles. The term 'unstructured' in this context denotes that there are no lanes or traffic rules to follow. Existing MPC formulations for passenger vehicles in structured environments do not readily apply to this context. Thus, a new nonlinear MPC formulation is developed to navigate an AGV from its initial position to a target position at high-speed safely. First, a new cost function formulation is used that aims to find the shortest path to the target position, since no reference trajectory exists in unstructured environments. Second, a region partitioning approach is used in conjunction with a multi-phase optimal control formulation to accommodate the complicated forms the obstacle-free region can assume due to the presence of multiple obstacles in the prediction horizon in an unstructured environment. Third, the no-wheel-lift-off condition, which is the major dynamical safety concern for high-speed, high-CoG AGVs, is ensured by limiting the steering angle within a range obtained offline using a 14 degrees-of-freedom vehicle dynamics model. Thus, a safe, high-speed navigation is enabled in an unstructured environment. Simulations of an AGV approaching multiple obstacles are provided to demonstrate the effectiveness of the algorithm.

Prism adaptation and generalization during visually guided locomotor tasks.

PubMed

Alexander, M Scott; Flodin, Brent W G; Marigold, Daniel S

2011-08-01

The ability of individuals to adapt locomotion to constraints associated with the complex environments normally encountered in everyday life is paramount for survival. Here, we tested the ability of 24 healthy young adults to adapt to a rightward prism shift (∼11.3°) while either walking and stepping to targets (i.e., precision stepping task) or stepping over an obstacle (i.e., obstacle avoidance task). We subsequently tested for generalization to the other locomotor task. In the precision stepping task, we determined the lateral end-point error of foot placement from the targets. In the obstacle avoidance task, we determined toe clearance and lateral foot placement distance from the obstacle before and after stepping over the obstacle. We found large, rightward deviations in foot placement on initial exposure to prisms in both tasks. The majority of measures demonstrated adaptation over repeated trials, and adaptation rates were dependent mainly on the task. On removal of the prisms, we observed negative aftereffects for measures of both tasks. Additionally, we found a unilateral symmetric generalization pattern in that the left, but not the right, lower limb indicated generalization across the 2 locomotor tasks. These results indicate that the nervous system is capable of rapidly adapting to a visuomotor mismatch during visually demanding locomotor tasks and that the prism-induced adaptation can, at least partially, generalize across these tasks. The results also support the notion that the nervous system utilizes an internal model for the control of visually guided locomotion.

Pretreatment and Membrane Hydrophilic Modification to Reduce Membrane Fouling

PubMed Central

Sun, Wen; Liu, Junxia; Chu, Huaqiang; Dong, Bingzhi

2013-01-01

The application of low pressure membranes (microfiltration/ultrafiltration) has undergone accelerated development for drinking water production. However, the major obstacle encountered in its popularization is membrane fouling caused by natural organic matter (NOM). This paper firstly summarizes the two factors causing the organic membrane fouling, including molecular weight (MW) and hydrophilicity/hydrophobicity of NOM, and then presents a brief introduction of the methods which can prevent membrane fouling such as pretreatment of the feed water (e.g., coagulation, adsorption, and pre-oxidation) and membrane hydrophilic modification (e.g., plasma modification, irradiation grafting modification, surface coating modification, blend modification, etc.). Perspectives of further research are also discussed. PMID:24956947

Assessing Institutional Characteristics on Microcredit Default in Kenya: A Comparative Analysis of Microfinance Institutions and Financial Intermediaries

ERIC Educational Resources Information Center

Muthoni, Muturi Phyllis

2016-01-01

A major concern on microcredit repayment remains a major obstacle to the Micro Financial Institutions (MFIs) and Financial Intermediaries (FIs) in Kenya. The health of MFI sector in Sub Sahara Africa (SSA) is a cause of concern due to the increased portfolio at risk (PAR). This region records the highest risk globally with its PAR 30 greater than…

Common Challenges Faced by Women of Color in Physics, and Actions Faculty Can Take to Minimize Those Challenges

ERIC Educational Resources Information Center

Johnson, Angela; Ong, Maria; Ko, Lily T.; Smith, Janet; Hodari, Apriel

2017-01-01

Women of color are deeply underrepresented in physics. Between 2002 and 2012, only 1% of graduating physics majors were Black women and another 1% were Latinas; only 61 American Indian women total completed degrees in physics in those years (out of 48,000 physics majors). This isolation can lead to additional obstacles that women of color majoring…

Mandatory Reporting and School Counselors: Reporting Laws, Obstacles, and Solutions

ERIC Educational Resources Information Center

Valkyrie, Karena T.; Creamer, D. Andrew; Vaughn, Leila

2008-01-01

Child abuse and neglect is a serious problem across our nation, and the consequences can be far reaching. Laws were enacted to address child abuse and identify mandatory reporters, including school counselors. In the literature, school counselors regularly report systemic and personal obstacles that influence their compliance with the mandatory…

Successful Information and Communication Technology Implementation Strategies for Rural Communities: An Investigation of Tech-Based Economic Development Programs

ERIC Educational Resources Information Center

Sullivan, Donna Annette

2009-01-01

Many rural communities across America face several obstacles in the implementation of information and communication technologies (ICTs) initiatives and struggle with the best approaches for leveraging these elements into an economic development strategy. These obstacles include: lack of quality local ICTs infrastructure, funding, inability to…

Misogyny, Women, and Obstacles to Tertiary Education: A Vile Situation.

ERIC Educational Resources Information Center

Stalker, Joyce

2001-01-01

Interviews with 18 women enrolled in postsecondary education used a framework of misogyny to reinterpret barriers to their participation Resulting themes included women's role in maintaining the home as sanctuary, women needing constraint, and men's role as suppressors. Results suggest how a theory based in misogyny can explain obstacles to…

Organizational factors in fire prevention: roles, obstacles, and recommendations

Treesearch

John R. Christiansen; William S. Folkman; Keith W. Warner; Michael L. Woolcott

1976-01-01

Problems being encountered in implementing fire prevention programs were explored by studying the organization for fire prevention at the Fish Lake, Uinta, and Wasatch National Forests in Utah. The study focused on role congruency in fire prevention activities and on the social and organizational obstacles to effective programs. The problems identified included lack of...

Discover 4-H Clubs: The Essential Resource for 4-H

ERIC Educational Resources Information Center

MacArthur, Stacey; Nelson, Cindy; Brower, Naomi; Memmott, Margie; Peterson, Gaelynn

2016-01-01

Obstacles facing new 4-H volunteers include time constraints and difficulty finding project-specific information, resources, and opportunities available for club members. As a solution to these obstacles and an aid for assisting volunteers in becoming confident in delivering information to youth, content experts produced Discover 4-H Clubs, a…

Women's Access to Higher Education in Tanzania: A Qualitative Study

ERIC Educational Resources Information Center

Johnson, Megan Patricia

2011-01-01

The purpose of this study was to reveal the ways in which first-generation women in Tanzania explained their success in pursuing a university education despite cultural and social obstacles. Such obstacles include social policies, socio-cultural factors, and academic factors. A review of the literature revealed that issues such as patriarchy,…

A reciprocity formulation for the EM scattering by an obstacle within a large open cavity

NASA Technical Reports Server (NTRS)

Pathak, Prabhakar H.; Burkholder, Robert J.

1993-01-01

A formulation based on a generalized reciprocity theorem is developed for analyzing the external high frequency EM scattering by a complex obstacle inside a relatively arbitrary open-ended waveguide cavity when it is illuminated by an external source. This formulation is also extended to include EM fields whose time dependence may be nonperiodic. A significant advantage of this formulation is that it allows one to break up the analysis into two independent parts; one deals with the waveguide cavity shape alone and the other with the obstacle alone. The external scattered field produced by the obstacle (in the presence of the waveguide cavity structure) is given in terms of a generalized reciprocity integral over a surface S(T) corresponding to the interior waveguide cavity cross section located conveniently but sufficiently close to the obstacle. Furthermore, the fields coupled into the cavity from the source in the exterior region generally need to propagate only one-way via the open front end (which is directly illuminated) to the interior surface S(T) in this approach, and not back, in order to find the external field scattered by the obstacle.

The impact of wind energy turbine piles on ocean dynamics

NASA Astrophysics Data System (ADS)

Grashorn, Sebastian; Stanev, Emil V.

2016-04-01

The small- and meso-scale ocean response to wind parks has not been investigated in the southern North Sea until now with the help of high-resolution numerical modelling. Obstacles such as e.g. wind turbine piles may influence the ocean current system and produce turbulent kinetic energy which could affect sediment dynamics in the surrounding area. Two setups of the unstructured-grid model SCHISM (Semi-implicit Cross-scale Hydroscience Integrated System Model) have been developed for an idealized channel including a surface piercing cylindrical obstacle representing the pile and a more realistic test case including four exemplary piles. Experiments using a constant flow around the obstacles and a rotating M2 tidal wave are carried out. The resulting current and turbulence patterns are investigated to estimate the influence of the obstacles on the surrounding ocean dynamics. We demonstrate that using an unstructured ocean model provides the opportunity to embed a high-resolution representation of a wind park turbine pile system into a coarser North Sea setup, which is needed in order to perform a seamless investigation of the resulting geophysical processes.

Sodium Hydroxide Pretreatment of Switchgrass for Ethanol Production

USDA-ARS?s Scientific Manuscript database

Lignocellulose-to-ethanol conversion is a promising technology to supplement corn-based ethanol production. However, the recalcitrant structure of lignocellulosic material is a major obstacle to the efficient conversion. To improve the enzymatic digestibility of switchgrass for the fermentable sugar...

Combating the drug-impaired driver : a prescription for safer highways.

DOT National Transportation Integrated Search

1985-01-01

In recent years, the Commonwealth of Virginia has increased its efforts to improve highway safety by combating the problems created by drunken drivers. However, law enforcement officials still face major obstacles in their efforts to detect and prose...

Optimizing anaerobic soil disinfestation for soilborne disease control

USDA-ARS?s Scientific Manuscript database

Soilborne disease management without chemical fumigants is a major challenge for strawberry production in California. Current re-registrations and regulations are likely to intensify this obstacle by severely limiting availability of fumigants on a large percentage of strawberry acreage. Anaerobic s...

Nanocarriers for treatment of ocular neovascularization in the back of the eye: new vehicles for ophthalmic drug delivery.

PubMed

Shen, Hsin-Hui; Chan, Elsa C; Lee, Jia Hui; Bee, Youn-Shen; Lin, Tsung-Wu; Dusting, Gregory J; Liu, Guei-Sheung

2015-01-01

Pathologic neovascularization of the retina is a major cause of substantial and irreversible loss of vision. Drugs are difficult to deliver to the lesions in the back of the eye and this is a major obstacle for the therapeutics. Current pharmacological approach involves an intravitreal injection of anti-VEGF agents to prevent aberrant growth of blood vessels, but it has limitations including therapeutic efficacy and side-effects associated with systemic exposure and invasive surgery. Nanotechnology provides novel opportunities to overcome the limitations of conventional delivery system to reach the back of the eye through fabrication of nanostructures capable of encapsulating and delivering small molecules. This review article introduces various forms of nanocarrier that can be adopted by ocular drug delivery systems to improve current therapy. The application of nanotechnology in medicine brings new hope for ocular drug delivery in the back of the eye to manage the major causes of blindness associated with ocular neovascularization.

Apparent motion perception in lower limb amputees with phantom sensations: "obstacle shunning" and "obstacle tolerance".

PubMed

Saetta, Gianluca; Grond, Ilva; Brugger, Peter; Lenggenhager, Bigna; Tsay, Anthony J; Giummarra, Melita J

2018-03-21

Phantom limbs are the phenomenal persistence of postural and sensorimotor features of an amputated limb. Although immaterial, their characteristics can be modulated by the presence of physical matter. For instance, the phantom may disappear when its phenomenal space is invaded by objects ("obstacle shunning"). Alternatively, "obstacle tolerance" occurs when the phantom is not limited by the law of impenetrability and co-exists with physical objects. Here we examined the link between this under-investigated aspect of phantom limbs and apparent motion perception. The illusion of apparent motion of human limbs involves the perception that a limb moves through or around an object, depending on the stimulus onset asynchrony (SOA) for the two images. Participants included 12 unilateral lower limb amputees matched for obstacle shunning (n = 6) and obstacle tolerance (n = 6) experiences, and 14 non-amputees. Using multilevel linear models, we replicated robust biases for short perceived trajectories for short SOA (moving through the object), and long trajectories (circumventing the object) for long SOAs in both groups. Importantly, however, amputees with obstacle shunning perceived leg stimuli to predominantly move through the object, whereas amputees with obstacle tolerance perceived leg stimuli to predominantly move around the object. That is, in people who experience obstacle shunning, apparent motion perception of lower limbs was not constrained to the laws of impenetrability (as the phantom disappears when invaded by objects), and legs can therefore move through physical objects. Amputees who experience obstacle tolerance, however, had stronger solidity constraints for lower limb apparent motion, perhaps because they must avoid co-location of the phantom with physical objects. Phantom limb experience does, therefore, appear to be modulated by intuitive physics, but not in the same way for everyone. This may have important implications for limb experience post-amputation (e.g., improving prosthesis embodiment when limb representation is constrained by the same limits as an intact limb). Copyright © 2018 Elsevier Ltd. All rights reserved.

Advancing the practice of health impact assessment in Canada: Obstacles and opportunities

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

McCallum, Lindsay C., E-mail: lindsay.mccallum@mail.utoronto.ca; Intrinsik Environmental Sciences Inc., 6605 Hurontario Street, Mississauga, Ontario L5T0A3; Ollson, Christopher A., E-mail: collson@intrinsik.com

Health Impact Assessment (HIA) is recognized as a useful tool that can identify potential health impacts resulting from projects or policy initiatives. Although HIA has become an established practice in some countries, it is not yet an established practice in Canada. In order to enable broader support for HIA, this study provides a comprehensive review and analysis of the peer-reviewed and gray literature on the state of HIA practice. The results of this review revealed that, although there is an abundance of publications relating to HIA, there remains a lack of transparent, consistent and reproducible approaches and methods throughout themore » process. Findings indicate a need for further research and development on a number of fronts, including: 1) the nature of HIA triggers; 2) consistent scoping and stakeholder engagement approaches; 3) use of evidence and transparency of decision-making; 4) reproducibility of assessment methods; 5) monitoring and evaluation protocols; and, 6) integration within existing regulatory frameworks. Addressing these issues will aid in advancing the more widespread use of HIA in Canada. - Highlights: • Reviewed current state of practice in the field of HIA • Identified key obstacles and opportunities for HIA advancement • Major issues include lack of consistent approach and methodology. • No national regulatory driver hinders opportunity for widespread use of HIA. • Identified research opportunities vital to developing HIA practice in Canada.« less

Antigenic variability: Obstacles on the road to vaccines against traditionally difficult targets.

PubMed

Servín-Blanco, R; Zamora-Alvarado, R; Gevorkian, G; Manoutcharian, K

2016-10-02

Despite the impressive impact of vaccines on public health, the success of vaccines targeting many important pathogens and cancers has to date been limited. The burden of infectious diseases today is mainly caused by antigenically variable pathogens (AVPs), which escape immune responses induced by prior infection or vaccination through changes in molecular structures recognized by antibodies or T cells. Extensive genetic and antigenic variability is the major obstacle for the development of new or improved vaccines against "difficult" targets. Alternative, qualitatively new approaches leading to the generation of disease- and patient-specific vaccine immunogens that incorporate complex permanently changing epitope landscapes of intended targets accompanied by appropriate immunomodulators are urgently needed. In this review, we highlight some of the most critical common issues related to the development of vaccines against many pathogens and cancers that escape protective immune responses owing to antigenic variation, and discuss recent efforts to overcome the obstacles by applying alternative approaches for the rational design of new types of immunogens.

Determinants, obstacles, sources and cooperation to innovation in Portuguese firms, using community innovation survey

NASA Astrophysics Data System (ADS)

Correia, Aldina; Braga, Alexandra; Braga, Vitor

2017-06-01

Innovation is a topic of interest for the management researchers, confirmed by the creation of a Community Innovation Survey, which is an harmonised tool designed to provide information about Innovation in European Union enterprises. In this study, we use factorial analysis to identify the determinants and obstacles to innovation in Portuguese firms. The sources of innovation and cooperation to innovation are also analysed, using crossed information. For the determinants of innovation six factors were identified: Production costs and impacts to health and environment, Process and product innovation, Organizational innovation, Institutional sources of information, Others sources of information and Market sources of information. Obstacles to innovation were clustered into three groups: Knowledge and market factors, Cost factors and Reasons not to innovate. The main sources of innovation identified, in this study, are Suppliers and Clients, located in Portugal and in Europe. Cooperation partners are also majority Clients and Suppliers, in addition to other enterprises in the same group.

Advanced robot locomotion.

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

Neely, Jason C.; Sturgis, Beverly Rainwater; Byrne, Raymond Harry

This report contains the results of a research effort on advanced robot locomotion. The majority of this work focuses on walking robots. Walking robot applications include delivery of special payloads to unique locations that require human locomotion to exo-skeleton human assistance applications. A walking robot could step over obstacles and move through narrow openings that a wheeled or tracked vehicle could not overcome. It could pick up and manipulate objects in ways that a standard robot gripper could not. Most importantly, a walking robot would be able to rapidly perform these tasks through an intuitive user interface that mimics naturalmore » human motion. The largest obstacle arises in emulating stability and balance control naturally present in humans but needed for bipedal locomotion in a robot. A tracked robot is bulky and limited, but a wide wheel base assures passive stability. Human bipedal motion is so common that it is taken for granted, but bipedal motion requires active balance and stability control for which the analysis is non-trivial. This report contains an extensive literature study on the state-of-the-art of legged robotics, and it additionally provides the analysis, simulation, and hardware verification of two variants of a proto-type leg design.« less

Studying time of flight imaging through scattering media across multiple size scales (Conference Presentation)

NASA Astrophysics Data System (ADS)

Velten, Andreas

2017-05-01

Light scattering is a primary obstacle to optical imaging in a variety of different environments and across many size and time scales. Scattering complicates imaging on large scales when imaging through the atmosphere when imaging from airborne or space borne platforms, through marine fog, or through fog and dust in vehicle navigation, for example in self driving cars. On smaller scales, scattering is the major obstacle when imaging through human tissue in biomedical applications. Despite the large variety of participating materials and size scales, light transport in all these environments is usually described with very similar scattering models that are defined by the same small set of parameters, including scattering and absorption length and phase function. We attempt a study of scattering and methods of imaging through scattering across different scales and media, particularly with respect to the use of time of flight information. We can show that using time of flight, in addition to spatial information, provides distinct advantages in scattering environments. By performing a comparative study of scattering across scales and media, we are able to suggest scale models for scattering environments to aid lab research. We also can transfer knowledge and methodology between different fields.

Establishing Medical Students' Cultural and Linguistic Competence for the Care of Spanish-Speaking Limited English Proficient Patients.

PubMed

Vela, Monica; Fritz, Cassandra; Jacobs, Elizabeth A

2016-09-01

Limited English proficient (LEP) patients are at risk of disparities in health and health care quality. These disparities can be mitigated by providing care in a language they understand. Undergraduate medical education provides an opportunity to stress that language barriers negatively impact the quality and safety of health care for LEP patients and to teach students how to overcome them. Because the preponderance of LEP patients in the USA is Spanish speaking, the majority of US medical schools have established medical Spanish coursework for interested students. However, 70 % of medical schools note significant obstacles to delivering this curriculum. The most commonly cited obstacles include a lack of time to deliver it, heterogeneous student skill levels, and insufficient faculty support. We also note that educators need to make sure not to propagate disparities and medical errors for LEP patients. We provide recommendations for establishing medical students' linguistic and cultural competence for the care Spanish-speaking limited English proficiency patients, with the caution that this instruction must be coupled with education as to when to call on an interpreter if participants are not fluent in Spanish at the end of the course.

Effects of aging on whole body and segmental control while obstacle crossing under impaired sensory conditions.

PubMed

Novak, Alison C; Deshpande, Nandini

2014-06-01

The ability to safely negotiate obstacles is an important component of independent mobility, requiring adaptive locomotor responses to maintain dynamic balance. This study examined the effects of aging and visual-vestibular interactions on whole-body and segmental control during obstacle crossing. Twelve young and 15 older adults walked along a straight pathway and stepped over one obstacle placed in their path. The task was completed under 4 conditions which included intact or blurred vision, and intact or perturbed vestibular information using galvanic vestibular stimulation (GVS). Global task performance significantly increased under suboptimal vision conditions. Vision also significantly influenced medial-lateral center of mass displacement, irrespective of age and GVS. Older adults demonstrated significantly greater trunk pitch and head roll angles under suboptimal vision conditions. Similar to whole-body control, no GVS effect was found for any measures of segmental control. The results indicate a significant reliance on visual but not vestibular information for locomotor control during obstacle crossing. The lack of differences in GVS effects suggests that vestibular information is not up-regulated for obstacle avoidance. This is not differentially affected by aging. In older adults, insufficient visual input appears to affect ability to minimize anterior-posterior trunk movement despite a slower obstacle crossing time and walking speed. Combined with larger medial-lateral deviation of the body COM with insufficient visual information, the older adults may be at a greater risk for imbalance or inability to recover from a possible trip when stepping over an obstacle. Copyright © 2014 Elsevier B.V. All rights reserved.

Wind field near complex terrain using numerical weather prediction model

NASA Astrophysics Data System (ADS)

Chim, Kin-Sang

The PennState/NCAR MM5 model was modified to simulate an idealized flow pass through a 3D obstacle in the Micro- Alpha Scale domain. The obstacle used were the idealized Gaussian obstacle and the real topography of Lantau Island of Hong Kong. The Froude number under study is ranged from 0.22 to 1.5. Regime diagrams for both the idealized Gaussian obstacle and Lantau island were constructed. This work is divided into five parts. The first part is the problem definition and the literature review of the related publications. The second part briefly discuss as the PennState/NCAR MM5 model and a case study of long- range transport is included. The third part is devoted to the modification and the verification of the PennState/NCAR MM5 model on the Micro-Alpha Scale domain. The implementation of the Orlanski (1976) open boundary condition is included with the method of single sounding initialization of the model. Moreover, an upper dissipative layer, Klemp and Lilly (1978), is implemented on the model. The simulated result is verified by the Automatic Weather Station (AWS) data and the Wind Profiler data. Four different types of Planetary Boundary Layer (PBL) parameterization schemes have been investigated in order to find out the most suitable one for Micro-Alpha Scale domain in terms of both accuracy and efficiency. Bulk Aerodynamic type of PBL parameterization scheme is found to be the most suitable PBL parameterization scheme. Investigation of the free- slip lower boundary condition is performed and the simulated result is compared with that with friction. The fourth part is the use of the modified PennState/NCAR MM5 model for an idealized flow simulation. The idealized uniform flow used is nonhydrostatic and has constant Froude number. Sensitivity test is performed by varying the Froude number and the regime diagram is constructed. Moreover, nondimensional drag is found to be useful for regime identification. The model result is also compared with the analytic results by Miles (1969) and Smith (1980, 1985), and the numerical results of Stein (1992), Miranda and James (1992) and Olaffson and Bougeault (1997). It is found that the simulated result in the present study is comparable with others. The fifth part is the construction of the regime diagram for the Lantau island of Hong Kong. All eight major wind directions are discussed.

Obstacles to the take-up of mental health-care provision by adult males in rural and remote areas of Australia: A systematic review protocol.

PubMed

Stroud, Peter; Lockwood, Craig

The objective is to identify and synthesise the best available evidence on the obstacles to the take-up of health-care provision by adult rural and remote dwelling males in Australia seeking mental health services. Men's health, in general health-care practice, is defined as the global management of mental, emotional, and physical health conditions, and related risk factors, that are specific to men in order to promote and generate optimal health.Research and practice tends to suggest that health-care and mental-health care practitioners seem to be confronted with obstacles such as distance clients need to travel and rurality in delivering care to adult rural males. Possible issues might be whether, or to what extent, care providers are conscious of these obstacles. Another issue might be how care providers work with these obstacles in practice, and whether or not they may, also to some extent, share some of the responsibility for the existence of these obstacles, on their own, or in conjunction with other factors which might be said to exist purely in the rural context. There is also a need to explore the contributions to obstacles from the adult rural male side as well. There may also be factors at work in the particular unique nature of rural and remote health-care and mental-health care as well, which could also be involved in the creation of obstacles.The structure and functioning of rural care available to adult males of all cultural backgrounds and the obstacles to the take-up of that care represents an area which warrants further exploration and understanding. A foundation paper in this field by Karoski suggests that obstacles exist in health-care provision, particularly in the field of mental-health care to adult males. Other research suggests that, while obstacles in service provision are common to all areas, some obstacles are more significant for rural and remote areas.The reasons for framing this review in terms of the adult rural and remote male (ARRM) context is as follows. Research suggests there is a consensus that Australian rural male health is a unique social problem, and there appears to be a possible perception that the state and national health systems may have failed ARRM's. This research also discusses that ARRM's respond differently and uniquely, compared to their international counterparts, and this might be especially true in the case of Australian Indigenous populations. There is a suggestion in the research that the Australian rural health-care environment is unique because of its mix of ARRM's among a population which includes culturally and linguistically diverse populations, local Indigenous people as well as people of Anglo-Saxon descent. Some research suggests that there are unique complexities confronting the ARRM population mix when access to health-care is considered. Research also suggests unique complexities might exist in the mix of care provision, delivery systems, and funding arrangements in the ARRM context. An interesting area of research in terms of social capital, and moral distress, suggests the Australian context might be unique in terms of its formal and informal care structures and arrangements.. Moral distress is believed to represent an issue in the professional delivery of quality health-care Other research considers the notion of structural disadvantage in the provision of, and access to, care services for ARRM's. Structural disadvantage refers to the dearth of asset-based community development opportunities that play a role in health-care provision.A screening search of Pubmed, Cinahl, the Cochrane Library and the JBI Systematic Review Library did not identify published systematic reviews, or active protocols in this topic of research. Therefore this systematic review will help address this gap. Obstacle: A barrier to the utilisation of health-care/mental-health care.Take-up: The accessing of health-care/mental-health care services.Health-care: Services which promote, maintain, and preserve health, life, and well-being.Mental-Health care: The assessment, diagnosis and treatment of people who are experiencing psychological and situational stressors which create mental-health conditions and disorders such as depression and anxiety.Provision: Professional services for health-care/mental-health care provided by Doctors, Nurses, Medical Specialists, Psychologists, Social Workers, Psychotherapists, and other care providers.Rural and Remote: This term can be conceptualised as a set of characteristics which can impact on the way a health-care service can be delivered and includes: geographical isolation from major population centres of Australia; greater distances; lower socioeconomic status; lower educational levels; higher proportion of Indigenous people; specific occupational health safety and welfare risks; a relatively close relationship with nature; specific cultural attitudes; poor access to services; and, smaller population centres where there is a distinctive occupational profile dominated by primary and resource production.

Stellar winds and planetary bodies simulations: Magnetized obstacles in super-Alfvénic and sub-Alfvénic flows

NASA Astrophysics Data System (ADS)

Vernisse, Y.; Riousset, J. A.; Motschmann, U.; Glassmeier, K.-H.

2017-03-01

Most planetary bodies are moving in the solar wind, in a stellar wind, or in a plasma flow within the magnetosphere of a planet. The interaction of the body with the flowing plasma provides us with various interaction types, which mainly depend on the flow speed, the magnetization of the body, its conductivity, the presence of an ionosphere, and the size of the body. We establish two cornerstones representing highly magnetized obstacles embedded in a super-Alfvénic and sub-Alfvénic plasma. Those two cornerstones complete the two cornerstones defined in our previous study on inert obstacles in super-Alfvénic and sub-Alfvénic regimes. Tracking the transitions between these cornerstones enable better understanding of the feedback of the obstacle onto the plasma flow. Each interaction is studied by means of the hybrid model simulation code AIKEF. The results are summarized in three dimensional diagrams showing the current structures, which serve as a basis for our descriptions. We identify the major currents such as telluric, magnetosonic, Chapman-Ferraro, and bow-shock currents as the signatures of the particular state of development of the interaction region. We show that each type of interactions can be identified by studying the shape and the magnitude of its specific currents.

Impaired anticipatory control of grasp during obstacle crossing in Parkinson's disease.

PubMed

McIsaac, Tara L; Diermayr, Gudrun; Albert, Frederic

2012-05-16

During self-paced walking, people with Parkinson's disease maintain anticipatory control during object grasping. However, common functional tasks often include carrying an object while changing step patterns mid-path and maneuvering over obstacles, increasing task complexity and attentional demands. Thus, the present study investigated the effect of Parkinson's disease on the modulation of grasping force changes as a function of gait-related inertial forces. Subjects with Parkinson's disease maintained the ability to scale and to couple over time their grip and inertial forces while walking at irregular step lengths, but were unable to maintain the temporal coupling of grasping forces compared to controls during obstacle crossing. We suggest that this deterioration in anticipatory control is associated with the increased demands of task complexity and attention during obstacle crossing. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Autonomous navigation system and method

DOEpatents

Bruemmer, David J [Idaho Falls, ID; Few, Douglas A [Idaho Falls, ID

2009-09-08

A robot platform includes perceptors, locomotors, and a system controller, which executes instructions for autonomously navigating a robot. The instructions repeat, on each iteration through an event timing loop, the acts of defining an event horizon based on the robot's current velocity, detecting a range to obstacles around the robot, testing for an event horizon intrusion by determining if any range to the obstacles is within the event horizon, and adjusting rotational and translational velocity of the robot accordingly. If the event horizon intrusion occurs, rotational velocity is modified by a proportion of the current rotational velocity reduced by a proportion of the range to the nearest obstacle and translational velocity is modified by a proportion of the range to the nearest obstacle. If no event horizon intrusion occurs, translational velocity is set as a ratio of a speed factor relative to a maximum speed.

Large-eddy simulation of turbulent flow with a surface-mounted two-dimensional obstacle

NASA Technical Reports Server (NTRS)

Yang, Kyung-Soo; Ferziger, Joel H.

1993-01-01

In this paper, we perform a large eddy simulation (LES) of turbulent flow in a channel containing a two-dimensional obstacle on one wall using a dynamic subgrid-scale model (DSGSM) at Re = 3210, based on bulk velocity above the obstacle and obstacle height; the wall layers are fully resolved. The low Re enables us to perform a DNS (Case 1) against which to validate the LES results. The LES with the DSGSM is designated Case 2. In addition, an LES with the conventional fixed model constant (Case 3) is conducted to allow identification of improvements due to the DSGSM. We also include LES at Re = 82,000 (Case 4) using conventional Smagorinsky subgrid-scale model and a wall-layer model. The results will be compared with the experiment of Dimaczek et al.

Apparatus for obstacle traversion

DOEpatents

Borenstein, Johann

2004-08-10

An apparatus for traversing obstacles having an elongated, round, flexible body that includes a plurality of drive track assemblies. The plurality of drive track assemblies cooperate to provide forward propulsion wherever a propulsion member is in contact with any feature of the environment, regardless of how many or which ones of the plurality of drive track assemblies make contact with such environmental feature.

3C.07: ARE THE PHYSICIANS RELUCTANT TO PRACTICE TELEMEDICINE IN HYPERTENSION?

PubMed

Sublet, M Lopez; Courand, P Y; Bally, S; Krummel, T; Dimitrov, Y; Brucker, M; Coz, S Regnier-Le; Dourmap-Collas, C; Mourad, J J; Steichen, O; Ott, J; Barone-Rochette, G; Bogetto-Graham, L; Rossignol, P; Barber-Chamoux, N; Le Jeune, S; Vautrin, E; Agnoletti, D; Baguet, S; Sosner, P

2015-06-01

The high number of patients with uncontrolled hypertension is still a public health pattern. The e-health contains all electronic health services used in order to improve communication between all the different actors. In arterial hypertension, few data exists on the possibilities: 1/ for patients to easily e-transfer their results of home blood pressure measurement (HBPM); 2/ for practitioners to receive and assess these HBPM results. Furthermore, physician's reluctance is often reported as a constraint for telemedicine development. Thus, we aimed to collect data on technical equipment of physicians, and on their expectations about this new way of relationship. 57 physicians, hypertension specialists (36 ± 8 years old, 56% men, mostly (88%) hospital practitioners) completed a self-administered questionnaire. The prevalence of technical equipment is summarized in Table 1. 77.1% of physicians thought that telemedicine could improve the control of hypertension, 29.8% thought they could provide less frequent consultations to their patients and 24.5 % that HBPM information would contribute to the fight against inertia. 83.2% of physicians would agree that HBPM data be transferred to a non- medical staff, a nurse in most cases (59.5%). Finally, while 89.5% of physicians declared they support the development of telemedicine in their daily practice, 100% of them found 3 kinds of "limits" to this exchange method. The main obstacles were: budget (49%), lack of legal frame (43%), medical reluctance (42%), difficulties in accessing or in mastering informatics tool (38.5%), confidentiality (28%), absence of direct benefit (21%), patient reluctance (21%).(Figure is included in full-text article.) : The equipment of physicians in home or mobile devices appears no longer an obstacle for the development of a program dedicated to telemedicine. The majority of medical practitioners working in specialized hypertension department agreed with Internet e-transfer of HBPM data, including paramedics. However, all physicians highlighted various obstacles to its expansion: technical support, lack of legal frame, and financial limits.

Translating Expertise into Effective Instruction: The Impacts of Cognitive Task Analysis (CTA) on Lab Report Quality and Student Retention in the Biological Sciences

ERIC Educational Resources Information Center

Feldon, David F.; Timmerman, Briana Crotwell; Stowe, Kirk A.; Showman, Richard

2010-01-01

Poor instruction has been cited as a primary cause of attrition from STEM majors and a major obstacle to learning for those who stay [Seymour and Hewitt [1997]. Talking about leaving: Why undergraduates leave the sciences. Boulder, CO: Westview]. Using a double-blind design, this study tests the hypothesis that the lack of explicit instructions in…

U.S. Wind projected to Be $60 billion business by 2013

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

NONE

2008-11-15

A recent U.S. Department of Energy report concluded that there are no insurmountable barriers to meeting 20 percent of U.S. electricity generation from wind by 2030, but identified upgrading of the transmission grid as a major challenge, requiring a $60+ billion investment. One major obstacle is the highly fragmented ownership of the 200,000-mile network among some 500 diverse, intensely territorial entities.

Assessing Borrower's and Business' Factors Causing Microcredit Default in Kenya: A Comparative Analysis of Microfinance Institutions and Financial Intermediaries

ERIC Educational Resources Information Center

Muthoni, Muturi Phyllis

2016-01-01

A major concern on microcredit repayment remains a major obstacle to the Micro Financial Institutions (MFIs) and Financial Intermediaries (FIs) in Kenya. The health of MFI sector in Sub Sahara Africa (SSA) is a cause of concern due to the increased portfolio at risk (PAR). This region records the highest risk globally. Its PAR 30 is greater than 5…

Multi-agent autonomous system

NASA Technical Reports Server (NTRS)

Fink, Wolfgang (Inventor); Dohm, James (Inventor); Tarbell, Mark A. (Inventor)

2010-01-01

A multi-agent autonomous system for exploration of hazardous or inaccessible locations. The multi-agent autonomous system includes simple surface-based agents or craft controlled by an airborne tracking and command system. The airborne tracking and command system includes an instrument suite used to image an operational area and any craft deployed within the operational area. The image data is used to identify the craft, targets for exploration, and obstacles in the operational area. The tracking and command system determines paths for the surface-based craft using the identified targets and obstacles and commands the craft using simple movement commands to move through the operational area to the targets while avoiding the obstacles. Each craft includes its own instrument suite to collect information about the operational area that is transmitted back to the tracking and command system. The tracking and command system may be further coupled to a satellite system to provide additional image information about the operational area and provide operational and location commands to the tracking and command system.

Progress and Challenges Associated with the Development of Ricin Toxin Subunit Vaccines

PubMed Central

Vance, David J.; Mantis, Nicholas J.

2016-01-01

Summary The past several years have seen major advances in the development of a safe and efficacious ricin toxin vaccine, including the completion of two Phase I clinical trials with two different recombinant A subunit (RTA)-based vaccines: RiVax™ and RVEc™ adsorbed to aluminum salt adjuvant, as well as a non-human primate study demonstrating that parenteral immunization with RiVax elicits a serum antibody response that was sufficient to protect against a lethal dose aerosolized ricin exposure. One of the major obstacles moving forward is assessing vaccine efficacy in humans, when neither ricin-specific serum IgG endpoint titers nor toxin-neutralizing antibody levels are accepted as definitive predictors of protective immunity. In this review we summarize ongoing efforts to leverage recent advances in our understanding of RTA-antibody interactions at the structural level to develop novel assays to predict vaccine efficacy in humans. PMID:26998662

Progress and challenges associated with the development of ricin toxin subunit vaccines.

PubMed

Vance, David J; Mantis, Nicholas J

2016-09-01

The past several years have seen major advances in the development of a safe and efficacious ricin toxin vaccine, including the completion of two Phase I clinical trials with two different recombinant A subunit (RTA)-based vaccines: RiVax™ and RVEc™ adsorbed to aluminum salt adjuvant, as well as a non-human primate study demonstrating that parenteral immunization with RiVax elicits a serum antibody response that was sufficient to protect against a lethal dose aerosolized ricin exposure. One of the major obstacles moving forward is assessing vaccine efficacy in humans, when neither ricin-specific serum IgG endpoint titers nor toxin-neutralizing antibody levels are accepted as definitive predictors of protective immunity. In this review we summarize ongoing efforts to leverage recent advances in our understanding of RTA-antibody interactions at the structural level to develop novel assays to predict vaccine efficacy in humans.

Combining high biodiversity with high yields in tropical agroforests.

PubMed

Clough, Yann; Barkmann, Jan; Juhrbandt, Jana; Kessler, Michael; Wanger, Thomas Cherico; Anshary, Alam; Buchori, Damayanti; Cicuzza, Daniele; Darras, Kevin; Putra, Dadang Dwi; Erasmi, Stefan; Pitopang, Ramadhanil; Schmidt, Carsten; Schulze, Christian H; Seidel, Dominik; Steffan-Dewenter, Ingolf; Stenchly, Kathrin; Vidal, Stefan; Weist, Maria; Wielgoss, Arno Christian; Tscharntke, Teja

2011-05-17

Local and landscape-scale agricultural intensification is a major driver of global biodiversity loss. Controversially discussed solutions include wildlife-friendly farming or combining high-intensity farming with land-sparing for nature. Here, we integrate biodiversity and crop productivity data for smallholder cacao in Indonesia to exemplify for tropical agroforests that there is little relationship between yield and biodiversity under current management, opening substantial opportunities for wildlife-friendly management. Species richness of trees, fungi, invertebrates, and vertebrates did not decrease with yield. Moderate shade, adequate labor, and input level can be combined with a complex habitat structure to provide high biodiversity as well as high yields. Although livelihood impacts are held up as a major obstacle for wildlife-friendly farming in the tropics, our results suggest that in some situations, agroforests can be designed to optimize both biodiversity and crop production benefits without adding pressure to convert natural habitat to farmland.

Combining high biodiversity with high yields in tropical agroforests

PubMed Central

Clough, Yann; Barkmann, Jan; Juhrbandt, Jana; Kessler, Michael; Wanger, Thomas Cherico; Anshary, Alam; Buchori, Damayanti; Cicuzza, Daniele; Darras, Kevin; Putra, Dadang Dwi; Erasmi, Stefan; Pitopang, Ramadhanil; Schmidt, Carsten; Schulze, Christian H.; Seidel, Dominik; Steffan-Dewenter, Ingolf; Stenchly, Kathrin; Vidal, Stefan; Weist, Maria; Wielgoss, Arno Christian; Tscharntke, Teja

2011-01-01

Local and landscape-scale agricultural intensification is a major driver of global biodiversity loss. Controversially discussed solutions include wildlife-friendly farming or combining high-intensity farming with land-sparing for nature. Here, we integrate biodiversity and crop productivity data for smallholder cacao in Indonesia to exemplify for tropical agroforests that there is little relationship between yield and biodiversity under current management, opening substantial opportunities for wildlife-friendly management. Species richness of trees, fungi, invertebrates, and vertebrates did not decrease with yield. Moderate shade, adequate labor, and input level can be combined with a complex habitat structure to provide high biodiversity as well as high yields. Although livelihood impacts are held up as a major obstacle for wildlife-friendly farming in the tropics, our results suggest that in some situations, agroforests can be designed to optimize both biodiversity and crop production benefits without adding pressure to convert natural habitat to farmland. PMID:21536873

An Algorithm for Autonomous Formation Obstacle Avoidance

NASA Astrophysics Data System (ADS)

Cruz, Yunior I.

The level of human interaction with Unmanned Aerial Systems varies greatly from remotely piloted aircraft to fully autonomous systems. In the latter end of the spectrum, the challenge lies in designing effective algorithms to dictate the behavior of the autonomous agents. A swarm of autonomous Unmanned Aerial Vehicles requires collision avoidance and formation flight algorithms to negotiate environmental challenges it may encounter during the execution of its mission, which may include obstacles and chokepoints. In this work, a simple algorithm is developed to allow a formation of autonomous vehicles to perform point to point navigation while avoiding obstacles and navigating through chokepoints. Emphasis is placed on maintaining formation structures. Rather than breaking formation and individually navigating around the obstacle or through the chokepoint, vehicles are required to assemble into appropriately sized/shaped sub-formations, bifurcate around the obstacle or negotiate the chokepoint, and reassemble into the original formation at the far side of the obstruction. The algorithm receives vehicle and environmental properties as inputs and outputs trajectories for each vehicle from start to the desired ending location. Simulation results show that the algorithm safely routes all vehicles past the obstruction while adhering to the aforementioned requirements. The formation adapts and successfully negotiates the obstacles and chokepoints in its path while maintaining proper vehicle separation.

Path planning of decentralized multi-quadrotor based on fuzzy-cell decomposition algorithm

NASA Astrophysics Data System (ADS)

Iswanto, Wahyunggoro, Oyas; Cahyadi, Adha Imam

2017-04-01

The paper aims to present a design algorithm for multi quadrotor lanes in order to move towards the goal quickly and avoid obstacles in an area with obstacles. There are several problems in path planning including how to get to the goal position quickly and avoid static and dynamic obstacles. To overcome the problem, therefore, the paper presents fuzzy logic algorithm and fuzzy cell decomposition algorithm. Fuzzy logic algorithm is one of the artificial intelligence algorithms which can be applied to robot path planning that is able to detect static and dynamic obstacles. Cell decomposition algorithm is an algorithm of graph theory used to make a robot path map. By using the two algorithms the robot is able to get to the goal position and avoid obstacles but it takes a considerable time because they are able to find the shortest path. Therefore, this paper describes a modification of the algorithms by adding a potential field algorithm used to provide weight values on the map applied for each quadrotor by using decentralized controlled, so that the quadrotor is able to move to the goal position quickly by finding the shortest path. The simulations conducted have shown that multi-quadrotor can avoid various obstacles and find the shortest path by using the proposed algorithms.

Access to jobs : a guide to innovative practices in welfare-to-work transportation

DOT National Transportation Integrated Search

1998-01-01

This series of short related articles looks at the role of transportation in supporting welfare to work reform. These articles find lack of timely affordable public transit is a major obstacle for welfare recipients attempting to find work. Strategie...

The Therapeutic Process in Clinical Social Work.

ERIC Educational Resources Information Center

Siporin, Max

1983-01-01

Suggests that current outmoded and inadequate conceptions of the therapeutic process are a major obstacle to the advancement of clinical social work practice. Presents an integrative ecosystem model that expresses the distinctive social work concern with person, situation, and helping relationship, in their reciprocal psychodynamic and…

Human factors in long-duration space flight

NASA Technical Reports Server (NTRS)

1972-01-01

A study, covering the behavioral, psychological, physiological, and medical factors of long duration manned space flight, is presented. An attempt was made to identify and resolve major obstacles and unknowns associated with such a flight. The costs and maintenance of the spacecraft system are also explored.

Decision Theory and the Governance of Technology.

ERIC Educational Resources Information Center

Woodhouse, Edward J.

1987-01-01

Provides an overview of the decision making process for science and technology. Finds that government agencies and officials are not the major decision makers. Examines obstacles to achieving intelligent decisions when policy makers are scientists, business executives, and consumers. Concludes with five strategies for improving technological…

Teaching Chromatography Using Virtual Laboratory Exercises

ERIC Educational Resources Information Center

Stone, David C.

2007-01-01

Though deceptively simple to teach, chromatography presents many nuances and complex interactions that challenge both student and instructor. Time and instrumentation provide major obstacles to a thorough examination of these details in the laboratory. Modern chromatographic method-development software provides an opportunity to overcome this,…

Wheelchair Navigation System for Disabled and Elderly People

PubMed Central

Kim, Eun Yi

2016-01-01

An intelligent wheelchair (IW) system is developed in order to support safe mobility for disabled or elderly people with various impairments. The proposed IW offers two main functions: obstacle detection and avoidance, and situation recognition. First, through a combination of a vision sensor and eight ultrasonic ones, it detects diverse obstacles and produces occupancy grid maps (OGMs) that describe environmental information, including the positions and sizes of obstacles, which is then given to the learning-based algorithm. By learning the common patterns among OGMs assigned to the same directions, the IW can automatically find paths to prevent collisions with obstacles. Second, it distinguishes a situation whereby the user is standing on a sidewalk, traffic intersection, or roadway through analyzing the texture and shape of the images, which aids in preventing any accidents that would result in fatal injuries to the user, such as collisions with vehicles. From the experiments that were performed in various environments, we can prove the following: (1) the proposed system can recognize different types of outdoor places with 98.3% accuracy; and (2) it can produce paths that avoid obstacles with 92.0% accuracy. PMID:27801852

A study on model fidelity for model predictive control-based obstacle avoidance in high-speed autonomous ground vehicles

NASA Astrophysics Data System (ADS)

Liu, Jiechao; Jayakumar, Paramsothy; Stein, Jeffrey L.; Ersal, Tulga

2016-11-01

This paper investigates the level of model fidelity needed in order for a model predictive control (MPC)-based obstacle avoidance algorithm to be able to safely and quickly avoid obstacles even when the vehicle is close to its dynamic limits. The context of this work is large autonomous ground vehicles that manoeuvre at high speed within unknown, unstructured, flat environments and have significant vehicle dynamics-related constraints. Five different representations of vehicle dynamics models are considered: four variations of the two degrees-of-freedom (DoF) representation as lower fidelity models and a fourteen DoF representation with combined-slip Magic Formula tyre model as a higher fidelity model. It is concluded that the two DoF representation that accounts for tyre nonlinearities and longitudinal load transfer is necessary for the MPC-based obstacle avoidance algorithm in order to operate the vehicle at its limits within an environment that includes large obstacles. For less challenging environments, however, the two DoF representation with linear tyre model and constant axle loads is sufficient.

Perceptions of women and men as entrepreneurs: evidence for differential effects of attributional augmenting.

PubMed

Baron, R A; Markman, G D; Hirsa, A

2001-10-01

It was hypothesized that perceptions of women who become entrepreneurs are enhanced by attributional augmenting because they adopt this role despite major obstacles to doing so. In contrast, attributional augmenting was expected to operate to a lesser degree for men who become entrepreneurs because they presumably face weaker obstacles. Three studies offered support for these hypotheses; all of these investigations used between-subjects designs in which women and men shown in standard-format photos were described to different groups of raters as being either entrepreneurs or managers. As predicted, raters assigned significantly higher scores to women, but not to men, when they were described as entrepreneurs.

Two Formal Gas Models For Multi-Agent Sweeping and Obstacle Avoidance

NASA Technical Reports Server (NTRS)

Kerr, Wesley; Spears, Diana; Spears, William; Thayer, David

2004-01-01

The task addressed here is a dynamic search through a bounded region, while avoiding multiple large obstacles, such as buildings. In the case of limited sensors and communication, maintaining spatial coverage - especially after passing the obstacles - is a challenging problem. Here, we investigate two physics-based approaches to solving this task with multiple simulated mobile robots, one based on artificial forces and the other based on the kinetic theory of gases. The desired behavior is achieved with both methods, and a comparison is made between them. Because both approaches are physics-based, formal assurances about the multi-robot behavior are straightforward, and are included in the paper.

An Evolutionary Framework for Understanding the Origin of Eukaryotes.

PubMed

Blackstone, Neil W

2016-04-27

Two major obstacles hinder the application of evolutionary theory to the origin of eukaryotes. The first is more apparent than real-the endosymbiosis that led to the mitochondrion is often described as "non-Darwinian" because it deviates from the incremental evolution championed by the modern synthesis. Nevertheless, endosymbiosis can be accommodated by a multi-level generalization of evolutionary theory, which Darwin himself pioneered. The second obstacle is more serious-all of the major features of eukaryotes were likely present in the last eukaryotic common ancestor thus rendering comparative methods ineffective. In addition to a multi-level theory, the development of rigorous, sequence-based phylogenetic and comparative methods represents the greatest achievement of modern evolutionary theory. Nevertheless, the rapid evolution of major features in the eukaryotic stem group requires the consideration of an alternative framework. Such a framework, based on the contingent nature of these evolutionary events, is developed and illustrated with three examples: the putative intron proliferation leading to the nucleus and the cell cycle; conflict and cooperation in the origin of eukaryotic bioenergetics; and the inter-relationship between aerobic metabolism, sterol synthesis, membranes, and sex. The modern synthesis thus provides sufficient scope to develop an evolutionary framework to understand the origin of eukaryotes.

Voluntary community service in medical school: a qualitative study on obstacles faced by student leaders and potential solutions

PubMed Central

Loh, Alvona Zi Hui; Tan, Julia Shi Yu; Lee, Jeannette Jen-Mai; Koh, Gerald Choon-Huat

2015-01-01

Purpose In medical school, students may participate in various community involvement projects (CIP), which serve disadvantaged communities. However, several obstacles may arise during these projects. The authors conducted a qualitative study with the primary aim of understanding the obstacles and corresponding potential solutions when medical students in Singapore participate in local CIP (LCIP) and overseas CIP (OCIP). Design The authors recruited medical students from Yong Loo Lin School of Medicine, National University of Singapore, who were also leaders of a specific community service project done in medical school. Twelve one-to-one interviews were held for the participants from 6 to 8 January 2013. Participants were led in a discussion based on an interview guide. The interviews were audio-recorded and transcribed into free-flow text. Subsequently, content and thematic analyses of the transcripts were performed independently by three researchers. Results The medical students faced many common obstacles during their community service projects. These obstacles include difficulties in recruiting and managing volunteers, attaining recognition or credibility for the project to acquire funding and resources, adjusting to a different culture or language, setting goals, and facing project-specific obstacles. Potential solutions were offered for some obstacles, such as building a strong executive committee for the project, grooming successive batches of leaders, and improving the project's public image, mentorship, reflections, and sustainability plans. Conclusions Mentorship, reflections, and sustainability are potential solutions that have been proposed to tackle the obstacles faced during community service participation in medical school. However, there may still be difficulty in solving some of the problems even after these measures are put into practice. Future research may focus on evaluating the effectiveness of these suggested solutions. PMID:26490690

Voluntary community service in medical school: a qualitative study on obstacles faced by student leaders and potential solutions.

PubMed

Loh, Alvona Zi Hui; Tan, Julia Shi Yu; Lee, Jeannette Jen-Mai; Koh, Gerald Choon-Huat

2015-01-01

In medical school, students may participate in various community involvement projects (CIP), which serve disadvantaged communities. However, several obstacles may arise during these projects. The authors conducted a qualitative study with the primary aim of understanding the obstacles and corresponding potential solutions when medical students in Singapore participate in local CIP (LCIP) and overseas CIP (OCIP). The authors recruited medical students from Yong Loo Lin School of Medicine, National University of Singapore, who were also leaders of a specific community service project done in medical school. Twelve one-to-one interviews were held for the participants from 6 to 8 January 2013. Participants were led in a discussion based on an interview guide. The interviews were audio-recorded and transcribed into free-flow text. Subsequently, content and thematic analyses of the transcripts were performed independently by three researchers. The medical students faced many common obstacles during their community service projects. These obstacles include difficulties in recruiting and managing volunteers, attaining recognition or credibility for the project to acquire funding and resources, adjusting to a different culture or language, setting goals, and facing project-specific obstacles. Potential solutions were offered for some obstacles, such as building a strong executive committee for the project, grooming successive batches of leaders, and improving the project's public image, mentorship, reflections, and sustainability plans. Mentorship, reflections, and sustainability are potential solutions that have been proposed to tackle the obstacles faced during community service participation in medical school. However, there may still be difficulty in solving some of the problems even after these measures are put into practice. Future research may focus on evaluating the effectiveness of these suggested solutions.

Formation of collisionless shocks in magnetized plasma interaction with kinetic-scale obstacles

DOE PAGES

Cruz, F.; Alves, E. P.; Bamford, R. A.; ...

2017-02-06

We investigate the formation of collisionless magnetized shocks triggered by the interaction between magnetized plasma flows and miniature-sized (order of plasma kinetic-scales) magnetic obstacles resorting to massively parallel, full particle-in-cell simulations, including the electron kinetics. The critical obstacle size to generate a compressed plasma region ahead of these objects is determined by independently varying the magnitude of the dipolar magnetic moment and the plasma magnetization. Here we find that the effective size of the obstacle depends on the relative orientation between the dipolar and plasma internal magnetic fields, and we show that this may be critical to form a shockmore » in small-scale structures. We also study the microphysics of the magnetopause in different magnetic field configurations in 2D and compare the results with full 3D simulations. Finally, we evaluate the parameter range where such miniature magnetized shocks can be explored in laboratory experiments.« less

Turbidity current flow over an erodible obstacle and phases of sediment wave generation

NASA Astrophysics Data System (ADS)

Strauss, Moshe; Glinsky, Michael E.

2012-06-01

We study the flow of particle-laden turbidity currents down a slope and over an obstacle. A high-resolution 2-D computer simulation model is used, based on the Navier-Stokes equations. It includes poly-disperse particle grain sizes in the current and substrate. Particular attention is paid to the erosion and deposition of the substrate particles, including application of an active layer model. Multiple flows are modeled from a lock release that can show the development of sediment waves (SW). These are stream-wise waves that are triggered by the increasing slope on the downstream side of the obstacle. The initial obstacle is completely erased by the resuspension after a few flows leading to self consistent and self generated SW that are weakly dependant on the initial obstacle. The growth of these waves is directly related to the turbidity current being self sustaining, that is, the net erosion is more than the net deposition. Four system parameters are found to influence the SW growth: (1) slope, (2) current lock height, (3) grain lock concentration, and (4) particle diameters. Three phases are discovered for the system: (1) "no SW," (2) "SW buildup," and (3) "SW growth". The second phase consists of a soliton-like SW structure with a preserved shape. The phase diagram of the system is defined by isolating regions divided by critical slope angles as functions of current lock height, grain lock concentration, and particle diameters.

The Role of Intestinal Microbiota in Acute Graft-versus-Host Disease.

PubMed

Chen, Yuanyuan; Zhao, Ye; Cheng, Qiao; Wu, Depei; Liu, Haiyan

2015-01-01

The mammalian intestinal microbiota is a complex ecosystem that plays an important role in host immune responses. Recent studies have demonstrated that alterations in intestinal microbiota composition are linked to multiple inflammatory diseases in humans, including acute graft-versus-host disease (aGVHD). aGVHD is one of the major obstacles in allogeneic hematopoietic stem cell transplantation (allo-HSCT), characterized by tissue damage in the gastrointestinal (GI) tract, liver, lung, and skin. Here, we review the current understanding of the role of intestinal microbiota in the control of immune responses during aGVHD. Additionally, the possibility of using probiotic strains for potential treatment or prevention of aGVHD will be discussed.

Fractures of the growing mandible.

PubMed

Kushner, George M; Tiwana, Paul S

2009-03-01

Oral and maxillofacial surgeons must constantly weigh the risks of surgical intervention for pediatric mandible fractures against the wonderful healing capacity of children. The majority of pediatric mandibular fractures can be managed with closed techniques using short periods of maxillomandibular fixation or training elastics alone. Generally, the use of plate- and screw-type internal fixation is reserved for difficult fractures. This article details general and special considerations for this surgery including: craniofacial growth & development, surgical anatomy, epidemiology evaluation, various fractures, the role rigid internal fixation and the Risdon cable in pediatric maxillofacial trauma. It concludes with suggestions concerning long-term follow-up care in light of the mobility, insurance obstacles, and family dynamics facing the patient population.

The Role of Intestinal Microbiota in Acute Graft-versus-Host Disease

PubMed Central

Chen, Yuanyuan; Zhao, Ye; Cheng, Qiao; Wu, Depei; Liu, Haiyan

2015-01-01

The mammalian intestinal microbiota is a complex ecosystem that plays an important role in host immune responses. Recent studies have demonstrated that alterations in intestinal microbiota composition are linked to multiple inflammatory diseases in humans, including acute graft-versus-host disease (aGVHD). aGVHD is one of the major obstacles in allogeneic hematopoietic stem cell transplantation (allo-HSCT), characterized by tissue damage in the gastrointestinal (GI) tract, liver, lung, and skin. Here, we review the current understanding of the role of intestinal microbiota in the control of immune responses during aGVHD. Additionally, the possibility of using probiotic strains for potential treatment or prevention of aGVHD will be discussed. PMID:26090477

Impact of exogenous sequences on the characteristics of an epidemic type 2 recombinant vaccine-derived poliovirus.

PubMed

Riquet, Franck B; Blanchard, Claire; Jegouic, Sophie; Balanant, Jean; Guillot, Sophie; Vibet, Marie-Anne; Rakoto-Andrianarivelo, Mala; Delpeyroux, Francis

2008-09-01

Pathogenic circulating vaccine-derived polioviruses (cVDPVs) have become a major obstacle to the successful completion of the global polio eradication program. Most cVDPVs are recombinant between the oral poliovirus vaccine (OPV) and human enterovirus species C (HEV-C). To study the role of HEV-C sequences in the phenotype of cVDPVs, we generated a series of recombinants between a Madagascar cVDPV isolate and its parental OPV type 2 strain. Results indicated that the HEV-C sequences present in this cVDPV contribute to its characteristics, including pathogenicity, suggesting that interspecific recombination contributes to the phenotypic biodiversity of polioviruses and may favor the emergence of cVDPVs.

NREL Research Overcomes Major Technical Obstacles in Magnesium-Metal

Science.gov Websites

Chunmei Ban are co-authors of the Nature Chemistry white paper, "An Artificial Interphase Enables corresponding author of the paper, "An Artificial Interphase Enables Reversible Magnesium Chemistry in an artificial solid-electrolyte interphase from polyacrylonitrile and magnesium-ion salt that

There's No Racial Justice without Economic Justice: Shortcomings of Clinton's Race Initiative Report.

ERIC Educational Resources Information Center

Dreier, Peter

1998-01-01

The widening disparity between wealth and poverty is the major obstacle to racial conciliation in the United States. Organized labor is the most important vehicle for challenging the widening gap between rich and poor to work for racial and economic justice. (SLD)

Signature pathway expression of xylose utilization in the genetically engineered industrial yeast Saccharomyces cerevisiae

USDA-ARS?s Scientific Manuscript database

Background: The limited xylose utilizing ability of native Saccharomyces cerevisiae has been a major obstacle for efficient cellulosic ethanol production from lignocellulosic materials. Haploid laboratory strains of S. cerevisiae are commonly used for genetic engineering to enable its xylose utiliza...

Drug-eluting coronary stents – focus on improved patient outcomes

PubMed Central

Jaffery, Zehra; Prasad, Amit; Lee, John H; White, Christopher J

2011-01-01

The development of stent has been a major advance in the treatment of obstructive coronary artery disease since the introduction of balloon angioplasty. Subsequently, neointimal hyperplasia within the stent leading to in-stent restenosis emerged as a major obstacle in long-term success of percutaneous coronary intervention. Recent introduction of drug-eluting stents is a major breakthrough to tackle this problem. This review article summarizes stent technology, reviews progress of drug-eluting stents and discusses quality of life, patient satisfaction, and acceptability of percutaneous coronary intervention. PMID:22915977

Internet Voice Distribution System (IVoDS) Utilization in Remote Payload Operations

NASA Technical Reports Server (NTRS)

Best, Susan; Bradford, Bob; Chamberlain, Jim; Nichols, Kelvin; Bailey, Darrell (Technical Monitor)

2002-01-01

Due to limited crew availability to support science and the large number of experiments to be operated simultaneously, telescience is key to a successful International Space Station (ISS) science program. Crew, operations personnel at NASA centers, and researchers at universities and companies around the world must work closely together to perform scientific experiments on-board ISS. NASA has initiated use of Voice over Internet Protocol (VoIP) to supplement the existing HVoDS mission voice communications system used by researchers. The Internet Voice Distribution System (IVoDS) connects researchers to mission support "loops" or conferences via Internet Protocol networks such as the high-speed Internet 2. Researchers use IVoDS software on personal computers to talk with operations personnel at NASA centers. IVoDS also has the capability, if authorized, to allow researchers to communicate with the ISS crew during experiment operations. NODS was developed by Marshall Space Flight Center with contractors A2 Technology, Inc. FVC, Lockheed- Martin, and VoIP Group. IVoDS is currently undergoing field-testing with full deployment for up to 50 simultaneous users expected in 2002. Research is currently being performed to take full advantage of the digital world - the Personal Computer and Internet Protocol networks - to qualitatively enhance communications among ISS operations personnel. In addition to the current voice capability, video and data-sharing capabilities are being investigated. Major obstacles being addressed include network bandwidth capacity and strict security requirements. Techniques being investigated to reduce and overcome these obstacles include emerging audio-video protocols and network technology including multicast and quality-of-service.

A five-week exercise program can reduce falls and improve obstacle avoidance in the elderly.

PubMed

Weerdesteyn, Vivian; Rijken, Hennie; Geurts, Alexander C H; Smits-Engelsman, Bouwien C M; Mulder, Theo; Duysens, Jacques

2006-01-01

Falls in the elderly are a major health problem. Although exercise programs have been shown to reduce the risk of falls, the optimal exercise components, as well as the working mechanisms that underlie the effectiveness of these programs, have not yet been established. To test whether the Nijmegen Falls Prevention Program was effective in reducing falls and improving standing balance, balance confidence, and obstacle avoidance performance in community-dwelling elderly people. A total of 113 elderly with a history of falls participated in this study (exercise group, n = 79; control group, n = 28; dropouts before randomization, n = 6). Exercise sessions were held twice weekly for 5 weeks. Pre- and post-intervention fall monitoring and quantitative motor control assessments were performed. The outcome measures were the number of falls, standing balance and obstacle avoidance performance, and balance confidence scores. The number of falls in the exercise group decreased by 46% (incidence rate ratio (IRR) 0.54, 95% confidence interval (CI) 0.36-0.79) compared to the number of falls during the baseline period and by 46% (IRR 0.54, 95% CI 0.34-0.86) compared to the control group. Obstacle avoidance success rates improved significantly more in the exercise group (on average 12%) compared to the control group (on average 6%). Quiet stance and weight-shifting measures did not show significant effects of exercise. The exercise group also had a 6% increase of balance confidence scores. The Nijmegen Falls Prevention Program was effective in reducing the incidence of falls in otherwise healthy elderly. There was no evidence of improved control of posture as a mechanism underlying this result. In contrast, an obstacle avoidance task indicated that subjects improved their performance. Laboratory obstacle avoidance tests may therefore be better instruments to evaluate future fall prevention studies than posturographic balance assessments. Copyright (c) 2006 S. Karger AG, Basel.

Fuzzy logic path planning system for collision avoidance by an autonomous rover vehicle

NASA Technical Reports Server (NTRS)

Murphy, Michael G.

1993-01-01

The Space Exploration Initiative of the United States will make great demands upon NASA and its limited resources. One aspect of great importance will be providing for autonomous (unmanned) operation of vehicles and/or subsystems in space flight and surface exploration. An additional, complicating factor is that much of the need for autonomy of operation will take place under conditions of great uncertainty or ambiguity. Issues in developing an autonomous collision avoidance subsystem within a path planning system for application in a remote, hostile environment that does not lend itself well to remote manipulation by Earth-based telecommunications is addressed. A good focus is unmanned surface exploration of Mars. The uncertainties involved indicate that robust approaches such as fuzzy logic control are particularly appropriate. Four major issues addressed are (1) avoidance of a fuzzy moving obstacle; (2) backoff from a deadend in a static obstacle environment; (3) fusion of sensor data to detect obstacles; and (4) options for adaptive learning in a path planning system. Examples of the need for collision avoidance by an autonomous rover vehicle on the surface of Mars with a moving obstacle would be wind-blown debris, surface flow or anomalies due to subsurface disturbances, another vehicle, etc. The other issues of backoff, sensor fusion, and adaptive learning are important in the overall path planning system.

Homophobia in the Workplace: Impact, Obstacles, and Interventions.

ERIC Educational Resources Information Center

Tucker, Gregory M.; Al-Timimi, Nada R.; Darrup, Carolyn R.; Jacobs, David B.; Lieberman, David M.; Templar-Eynon, Shane A.; von Zuben, Frank C.; Washington, Syreeta D.

This roundtable offered a springboard for discussion on homophobia in the workplace in four major areas: education, industry, mental health, and public service. In the discussion on education, gay, lesbian, and bisexual (GLB) college students explored ingrained attitudes and beliefs that impact their college life. Other issues explored in academia…

Tuition vs. Intuition: Effects of Instruction on Naive Theories of Evolution

ERIC Educational Resources Information Center

Shtulman, Andrew; Calabi, Prassede

2013-01-01

Recent research suggests that a major obstacle to evolution understanding is an essentialist view of the biological world. The present study investigated the effects of formal biology instruction on such misconceptions. Participants (N = 291) completed an assessment of their understanding of six aspects of evolution (variation, inheritance,…

Students' Reasons for Preferring Teleological Explanations

ERIC Educational Resources Information Center

Trommler, Friederike; Gresch, Helge; Hammann, Marcus

2018-01-01

The teleological bias, a major learning obstacle, involves explaining biological phenomena in terms of purposes and goals. To probe the teleological bias, researchers have used acceptance judgement tasks and preference judgement tasks. In the present study, such tasks were used with German high school students (N = 353) for 10 phenomena from human…

South Africa after Apartheid: Recent Developments and Future Prospects.

ERIC Educational Resources Information Center

Brook, Diane L.

1997-01-01

Profiles the process of South Africa's transformation into a democracy. Outlines the many characteristics of the transition from white to majority rule, such as the attempt to achieve catharsis and bury the apartheid past through a process of amnesty and reconciliation. Describes the remaining obstacles to that transition. (MJP)

A novel abutment construction technique for rapid bridge construction : controlled low strength Materials (CLSM) with full-height concrete panels.

DOT National Transportation Integrated Search

2012-01-01

One of the major obstacles facing rapid bridge construction for typical span type bridges is the time required to construct bridge abutments and foundations. This can be remedied by using the controlled low strength materials (CLSM) bridge abutment. ...

Some Thoughts on Teaching about Ultraviolet Radiation

ERIC Educational Resources Information Center

Thumm, Walter

1975-01-01

Describes the major obstacles in the study of ultraviolet radiation (UV). Presents the beneficial aspects of UV such as vitamin O production, sterilization, clinical treatment of diseases and wounds, and the marking of patients for radiotherapy. Warns of the dangers of UV exposure such as skin cancer and early aging. (GS)

Overcoming Resistance to Change

ERIC Educational Resources Information Center

Hull, Ted H.; Balka, Don S.; Miles, Ruth Harbin

2010-01-01

Resistance to change is a major obstacle in developing and implementing effective instructional programs, yet it is rarely considered, discussed, or addressed. The school leaders who are responsible for improvement frequently feel that their efforts are being blocked or thwarted. For the most part, they are correct, but they may not realize that…

The Young Achiever

ERIC Educational Resources Information Center

Olson, Cathy Applefeld

2012-01-01

The author profiles Kasey Dallman, a Wisconsin college junior who has overcome major obstacles and made even greater strides as she works to become a music educator. Skilled musician, published novelist, secretary of a NAfME collegiate chapter--this Wisconsin music educator-to-be is already making a name for herself. To scan Kasey Dallman's resume…

A Conservation Plan for the Transylvania University Library.

ERIC Educational Resources Information Center

Bryson, Kathleen; Mayo, Lynn

This assessment of the conservation needs of the Frances Corrick Thomas Library begins with an examination of the architectural and environmental peculiarities of the existing building, which is seen as a major obstacle to achieving an effective conservation program. Needs are identified and recommendations for immediate and intermediate action,…

Moving beyond Brownies and Pizza

ERIC Educational Resources Information Center

Freeman, Daniel W.; Jorgensen, Theresa A.

2015-01-01

A lack of fractional understanding is a well-documented obstacle to student achievement in upper elementary and middle school math (National Center for Educational Statistics [NCES] 1999; Lamon 1999; National Research Council [NRC] 2001). Lamon (1999) notes that one major conceptual hurdle that students must overcome is the idea that fractions are…

Symposium Overview: Are We Making the Same Mistake Twice?

ERIC Educational Resources Information Center

Holburn, C. Steve

1992-01-01

This symposium overview briefly summarizes following articles which identify problems in the quality of care provided by Intermediate Care Facilities for the Mentally Retarded (ICF/MR), provide reactions, and identify positive trends. An emphasis on regulations and compliance is thought to be a major obstacle to quality services. (DB)

Immunopathology and Cytokine Responses in Commercial Broiler Chickens with Gangrenous Dermatitis

USDA-ARS?s Scientific Manuscript database

Gangrene dermatitis (GD) is an emerging disease of increasing economic importance in poultry that results from infection by Clostridium septicum and C. perfringens (CP) type A. Lack of a reproducible disease model has been a major obstacle in understanding the immunopathology of GD. To gain better u...

Approaches to Education about a World Economy.

ERIC Educational Resources Information Center

Nelson, Jack L.

A rationale for skeptical and controversial teaching about world economics is presented by maintaining that the nature of economics is controversial and that ideology and nationalism are dominant obstacles in economics education. Following an introduction, the first of six sections discusses major stereotypes and perceptions in economics. The next…

The Urban University in America.

ERIC Educational Resources Information Center

Berube, Maurice R.

The urban university has become the dominant institution of higher learning in America. Although the concept of university is in keeping with traditions in American higher education, there are major obstacles to the fulfillment of the urban university's purpose. The urban college and university have great potential in playing an increasingly…

U. S. Veterinary Immune Reagents Network: Progress with poultry immune reagents development

USDA-ARS?s Scientific Manuscript database

A major obstacle to advances in veterinary immunology and disease research is the lack of sufficient immunological reagents specific for veterinary animal species. In 2006, U. S. Veterinary Immune Reagent Network (VIRN) Consortium (www.vetimm.org) was developed to develop immune reagents against ma...

Resource Issues: A Case Study from New Orleans.

ERIC Educational Resources Information Center

Garvin, James R.; Young, Alma H.

1993-01-01

One major obstacle to collaboration is perception of value--especially in urban areas where resources are shrinking and social problems are increasing. Sharing of resources is weighted by considerations of proximal benefit and proximal concern. This article shows how a New Orleans full-services school pilot project successfully garnered funding…

Control of Saprolegniasis on sunshine bass eggs with copper sulfate

USDA-ARS?s Scientific Manuscript database

A major obstacle to successful hatchery production is water-mould (Saprolegniasis) growth on eggs. Copper sulfate (CuSO4) is commonly used to control Saprolegnia species in channel catfish hatcheries that use troughs, but the effectiveness of it on fish eggs hatched using different systems was not ...

Textiles and Training in Portugal.

ERIC Educational Resources Information Center

Andrez, Jaime Serrao; Dias, Mario Caldeira

Analyzing the role of vocational training in an economic sector that is declining in Portugal, this document consists of five chapters, a bibliography, and a list of training organizations. An introduction tells why the study is important and explains that the major obstacles to development of the Portuguese textile and clothing sector are the…

Understanding the Learning Process in SMEs

ERIC Educational Resources Information Center

Carr, James; Gannon-Leary, Pat

2007-01-01

A major obstacle to the diffusion of management development learning technologies from Higher Education Institutions to Small and Medium-sized Enterprises (SMEs) is a lack of understanding about how SME learners learn. This article examines the nature of learning in SMEs and considers the incidence of informal support for informal learning.…

Imagination Unlimited: A Guide for Creative Problem Solving, Upper Elementary Summer School.

ERIC Educational Resources Information Center

Cleveland Public Schools, OH. Div. of Major Work Classes.

The guide gives procedures for helping gifted upper elementary school students in Major Work classes utilize their imagination. Appropriate literary quotes introduce a discussion on creativity, which involves the imaginative recombination of known ideas into something new. Considered are obstacles that work against creativity such as mental…

Distinguishing Sarcasm from Literal Language: Evidence from Books and Blogging

ERIC Educational Resources Information Center

Kovaz, David; Kreuz, Roger J.; Riordan, Monica A.

2013-01-01

Sarcasm production and comprehension have been traditionally described in terms of pragmatic factors. Lexical cues have received less attention, but they may be important potential indicators. A major obstacle to examining such features is determining sarcastic intent. One solution is to analyze statements explicitly marked as being sarcastic.…

Institutionalization of Rural Credit in India: A Focus on the Cooperative Credit Movement.

DTIC Science & Technology

1980-05-01

Primarily the Government of India has relied on the Cooperative Movement in its effort to institutionalize the supply of rural credit. This thesis...examines some of the major problems and obstacles encountered as well as corrective measures taken with respect to the cooperative movement . (Author)

A soft robot capable of 2D mobility and self-sensing for obstacle detection and avoidance

NASA Astrophysics Data System (ADS)

Qin, Lei; Tang, Yucheng; Gupta, Ujjaval; Zhu, Jian

2018-04-01

Soft robots have shown great potential for surveillance applications due to their interesting attributes including inherent flexibility, extreme adaptability, and excellent ability to move in confined spaces. High mobility combined with the sensing systems that can detect obstacles plays a significant role in performing surveillance tasks. Extensive studies have been conducted on movement mechanisms of traditional hard-bodied robots to increase their mobility. However, there are limited efforts in the literature to explore the mobility of soft robots. In addition, little attempt has been made to study the obstacle-detection capability of a soft mobile robot. In this paper, we develop a soft mobile robot capable of high mobility and self-sensing for obstacle detection and avoidance. This robot, consisting of a dielectric elastomer actuator as the robot body and four electroadhesion actuators as the robot feet, can generate 2D mobility, i.e. translations and turning in a 2D plane, by programming the actuation sequence of the robot body and feet. Furthermore, we develop a self-sensing method which models the robot body as a deformable capacitor. By measuring the real-time capacitance of the robot body, the robot can detect an obstacle when the peak capacitance drops suddenly. This sensing method utilizes the robot body itself instead of external sensors to achieve detection of obstacles, which greatly reduces the weight and complexity of the robot system. The 2D mobility and self-sensing capability ensure the success of obstacle detection and avoidance, which paves the way for the development of lightweight and intelligent soft mobile robots.

A Virtual Blind Cane Using a Line Laser-Based Vision System and an Inertial Measurement Unit

PubMed Central

Dang, Quoc Khanh; Chee, Youngjoon; Pham, Duy Duong; Suh, Young Soo

2016-01-01

A virtual blind cane system for indoor application, including a camera, a line laser and an inertial measurement unit (IMU), is proposed in this paper. Working as a blind cane, the proposed system helps a blind person find the type of obstacle and the distance to it. The distance from the user to the obstacle is estimated by extracting the laser coordinate points on the obstacle, as well as tracking the system pointing angle. The paper provides a simple method to classify the obstacle’s type by analyzing the laser intersection histogram. Real experimental results are presented to show the validity and accuracy of the proposed system. PMID:26771618

Identification and analysis of obstacles in bioterrorism preparedness and response

NASA Astrophysics Data System (ADS)

Sincavage, Suzanne Michele

The focus of this study was to identify and analyze the obstacles to bioterrorism preparedness and response facing emergency management agencies and public authorities. In order to establish the limits of this discussion, the obstacles will examine a combined conceptual framework of public health, environmental security and social response. The interdisciplinary characteristics of this framework are ideal for addressing the issue of bioterrorism because of its simultaneous impact, which encompasses the complex interrelationships that pertain to public health and national security and social response. Based on a review of literature, the obstacles presented range from the absence of an effective surveillance system for biological terrorism related diseases to the inadequate training of first responders in bioterrorism preparedness and the difficult challenges of a mass casualty situation and the intense pressures associated with the crisis response. Furthermore, the impending reality of bioterrorism will further illustrate a close examination of the characteristics and management of three major biowarfare agents---anthrax, plague and smallpox. Finally, to provide a realistic understanding of the impact of bioterrorism, three case studies of actual events and two hypothetical scenarios will be discussed. Specifically, the discussion will provide the following three unconventional terrorist attacks: the recent anthrax attacks of 2001, the Aum Shinrikyo's attack of the Tokyo subway in 1995, and the Rajneeshees' use of salmonella poisoning in 1994. The inclusion of the hypothetical scenarios of two massive outbreaks of smallpox and anthrax will be presented to illuminate the seriousness and magnitude of the threat of bioterrorism and the probable consequences of failing to overcome the obstacles presented in this study. The importance of this research cannot be overemphasized, the threat is undeniably serious, and the potential for biological agents to cause devastating casualties can be minimized with the fighting strength of education.

Reactive navigation in extremely dense and highly intricate environments

PubMed Central

2017-01-01

Reactive navigation is a well-known paradigm for controlling an autonomous mobile robot, which suggests making all control decisions through some light processing of the current/recent sensor data. Among the many advantages of this paradigm are: 1) the possibility to apply it to robots with limited and low-priced hardware resources, and 2) the fact of being able to safely navigate a robot in completely unknown environments containing unpredictable moving obstacles. As a major disadvantage, nevertheless, the reactive paradigm may occasionally cause robots to get trapped in certain areas of the environment—typically, these conflicting areas have a large concave shape and/or are full of closely-spaced obstacles. In this last respect, an enormous effort has been devoted to overcome such a serious drawback during the last two decades. As a result of this effort, a substantial number of new approaches for reactive navigation have been put forward. Some of these approaches have clearly improved the way how a reactively-controlled robot can move among densely cluttered obstacles; some other approaches have essentially focused on increasing the variety of obstacle shapes and sizes that could be successfully circumnavigated; etc. In this paper, as a starting point, we choose the best existing reactive approach to move in densely cluttered environments, and we also choose the existing reactive approach with the greatest ability to circumvent large intricate-shaped obstacles. Then, we combine these two approaches in a way that makes the most of them. From the experimental point of view, we use both simulated and real scenarios of challenging complexity for testing purposes. In such scenarios, we demonstrate that the combined approach herein proposed clearly outperforms the two individual approaches on which it is built. PMID:29287078

Flow through a very porous obstacle in a shallow channel.

PubMed

Creed, M J; Draper, S; Nishino, T; Borthwick, A G L

2017-04-01

A theoretical model, informed by numerical simulations based on the shallow water equations, is developed to predict the flow passing through and around a uniform porous obstacle in a shallow channel, where background friction is important. This problem is relevant to a number of practical situations, including flow through aquatic vegetation, the performance of arrays of turbines in tidal channels and hydrodynamic forces on offshore structures. To demonstrate this relevance, the theoretical model is used to (i) reinterpret core flow velocities in existing laboratory-based data for an array of emergent cylinders in shallow water emulating aquatic vegetation and (ii) reassess the optimum arrangement of tidal turbines to generate power in a tidal channel. Comparison with laboratory-based data indicates a maximum obstacle resistance (or minimum porosity) for which the present theoretical model is valid. When the obstacle resistance is above this threshold the shallow water equations do not provide an adequate representation of the flow, and the theoretical model over-predicts the core flow passing through the obstacle. The second application of the model confirms that natural bed resistance increases the power extraction potential for a partial tidal fence in a shallow channel and alters the optimum arrangement of turbines within the fence.

Evaluation of Mental Workload among ICU Ward's Nurses.

PubMed

Mohammadi, Mohsen; Mazloumi, Adel; Kazemi, Zeinab; Zeraati, Hojat

2015-01-01

High level of workload has been identified among stressors of nurses in intensive care units (ICUs). The present study investigated nursing workload and identified its influencing perfor-mance obstacles in ICUs. This cross-sectional study was conducted, in 2013, on 81 nurses working in ICUs in Imam Khomeini Hospital in Tehran, Iran. NASA-TLX was applied for assessment of workload. Moreover, ICUs Performance Obstacles Questionnaire was used to identify performance obstacles associated with ICU nursing. Physical demand (mean=84.17) was perceived as the most important dimensions of workload by nurses. The most critical performance obstacles affecting workload included: difficulty in finding a place to sit down, hectic workplace, disorganized workplace, poor-conditioned equipment, waiting for using a piece of equipment, spending much time seeking for supplies in the central stock, poor quality of medical materials, delay in getting medications, unpredicted problems, disorganized central stock, outpatient surgery, spending much time dealing with family needs, late, inadequate, and useless help from nurse assistants, and ineffective morning rounds (P-value<0.05). Various performance obstacles are correlated with nurses' workload, affirms the significance of nursing work system characteristics. Interventions are recommended based on the results of this study in the work settings of nurses in ICUs.

Didactical Design Material Units of Distance and Speed to Developed Mathematical Connection in Elementary School

NASA Astrophysics Data System (ADS)

Jannah, R. R.; Apriliya, S.; Karlimah

2017-03-01

This study aims to develop alternative instructional design based of barriers learning which identified by developing mathematical connection capabilities to the material unit of distance and speed. The research was conducted in the fifth grade elementary school Instructional design is complemented with a hypothetical learning trajectory in the form of a pedagogical didactic anticipation. The method used is descriptive method with qualitative approach. Techniques data collection used were observation, interviews, and documentation. The instrument used the researchers themselves are equipped with an instrument written test. The data were analyzed qualitatively to determine the student learning obstacles, then arrange hypothetical learning trajectory and pedagogical didactic anticipation. Learning obstacle are identified, it is learning obstacle related the connections between mathematical topics, learning obstacle related with other disciplines, and learning obstacle related with everyday life. The results of this research are improvement and development of didactic design in mathematics which has activities mathematical connection to the material unit of distance and speed in elementary school. The learning activities are carried out is using varied methods include method lectures, demonstrations, practice and exercise, as well as using the modified instructional media.

Thermal activation of dislocations in large scale obstacle bypass

NASA Astrophysics Data System (ADS)

Sobie, Cameron; Capolungo, Laurent; McDowell, David L.; Martinez, Enrique

2017-08-01

Dislocation dynamics simulations have been used extensively to predict hardening caused by dislocation-obstacle interactions, including irradiation defect hardening in the athermal case. Incorporating the role of thermal energy on these interactions is possible with a framework provided by harmonic transition state theory (HTST) enabling direct access to thermally activated reaction rates using the Arrhenius equation, including rates of dislocation-obstacle bypass processes. Moving beyond unit dislocation-defect reactions to a representative environment containing a large number of defects requires coarse-graining the activation energy barriers of a population of obstacles into an effective energy barrier that accurately represents the large scale collective process. The work presented here investigates the relationship between unit dislocation-defect bypass processes and the distribution of activation energy barriers calculated for ensemble bypass processes. A significant difference between these cases is observed, which is attributed to the inherent cooperative nature of dislocation bypass processes. In addition to the dislocation-defect interaction, the morphology of the dislocation segments pinned to the defects play an important role on the activation energies for bypass. A phenomenological model for activation energy stress dependence is shown to describe well the effect of a distribution of activation energies, and a probabilistic activation energy model incorporating the stress distribution in a material is presented.

Development of an integrated BEM approach for hot fluid structure interaction

NASA Technical Reports Server (NTRS)

Dargush, G. F.; Banerjee, P. K.

1989-01-01

The progress made toward the development of a boundary element formulation for the study of hot fluid-structure interaction in Earth-to-Orbit engine hot section components is reported. The convective viscous integral formulation was derived and implemented in the general purpose computer program GP-BEST. The new convective kernel functions, in turn, necessitated the development of refined integration techniques. As a result, however, since the physics of the problem is embedded in these kernels, boundary element solutions can now be obtained at very high Reynolds number. Flow around obstacles can be solved approximately with an efficient linearized boundary-only analysis or, more exactly, by including all of the nonlinearities present in the neighborhood of the obstacle. The other major accomplishment was the development of a comprehensive fluid-structure interaction capability within GP-BEST. This new facility is implemented in a completely general manner, so that quite arbitrary geometry, material properties and boundary conditions may be specified. Thus, a single analysis code (GP-BEST) can be used to run structures-only problems, fluids-only problems, or the combined fluid-structure problem. In all three cases, steady or transient conditions can be selected, with or without thermal effects. Nonlinear analyses can be solved via direct iteration or by employing a modified Newton-Raphson approach.

Obstacles to TQM success in health care systems.

PubMed

Mosadeghrad, Ali Mohammad

2013-01-01

Many healthcare organisations have found it difficult to implement total quality management (TQM) successfully. The aim of this paper is to explore the barriers to TQM successful implementation in the healthcare sector. This paper reports a literature review exploring the major reasons for the failure of TQM programmes in healthcare organisations. TQM implementation and its impact depend heavily on the ability of managers to adopt and adapt its values and concepts in professional healthcare organisations. Unsuccessful TQM efforts in healthcare organisations can be attributed to the strongly departmentalised, bureaucratic and hierarchical structure, professional autonomy, tensions between managers and professionals and the difficulties involved in evaluating healthcare processes and outcomes. Other obstacles to TQM success include lack of consistent managers' and employees' commitment to and involvement in TQM implementation, poor leadership and management, lack of a quality-oriented culture, insufficient training, and inadequate resources. The review was limited to empirical articles written in the English language during the past 30 years (1980-2010). The findings of this article provide policy makers and managers with a practical understanding of the factors that are likely to obstruct TQM implementation in the healthcare sector. Understanding the factors that obstruct TQM implementation would enable managers to develop more effective strategies for implementing TQM successfully in healthcare organisations.

Using Multidisciplinary Focus Groups to Inform the Development of mI SMART: A Nurse-Led Technology Intervention for Multiple Chronic Conditions

PubMed Central

Theeke, Laurie A.; Theeke, Elliott; Mallow, Brian K.

2016-01-01

Used as integrated tools, technology may improve the ability of healthcare providers to improve access and outcomes of care. Little is known about healthcare teams' preferences in using such technology. This paper reports the findings from focus groups aimed at evaluating a newly developed primary care technology platform. Focus groups were completed in academic, outpatient, and community settings. Focus groups were attended by 37 individuals. The participants included professionals from multiple disciplines. Both prescribing (N = 8) and nonprescribing healthcare team members (n = 21) completed the focus groups and survey. The majority were practicing for more than 20 years (44.8%) in an outpatient clinic (62%) for 20–40 hours per week (37.9%). Providers identified perceived obstacles of patient use as ability, willingness, and time. System obstacles were identified as lack of integration, lack of reimbursement, and cost. The positive attributes of the developed system were capability for virtual visits, readability, connectivity, user-friendliness, ability to capture biophysical measures, enhanced patient access, and incorporation of multiple technologies. Providers suggested increasing capability for biophysical and symptom monitoring for more common chronic conditions. Technology interventions have the potential to improve access and outcomes but will not be successful without the input of users. PMID:27504199

Robotic guarded motion system and method

DOEpatents

Bruemmer, David J.

2010-02-23

A robot platform includes perceptors, locomotors, and a system controller. The system controller executes instructions for repeating, on each iteration through an event timing loop, the acts of defining an event horizon, detecting a range to obstacles around the robot, and testing for an event horizon intrusion. Defining the event horizon includes determining a distance from the robot that is proportional to a current velocity of the robot and testing for the event horizon intrusion includes determining if any range to the obstacles is within the event horizon. Finally, on each iteration through the event timing loop, the method includes reducing the current velocity of the robot in proportion to a loop period of the event timing loop if the event horizon intrusion occurs.

Application of Optical Flow Sensors for Dead Reckoning, Heading Reference, Obstacle Detection, and Obstacle Avoidance

DTIC Science & Technology

2015-09-01

OPTICAL FLOW SENSORS FOR DEAD RECKONING, HEADING REFERENCE, OBSTACLE DETECTION, AND OBSTACLE AVOIDANCE by Tarek M. Nejah September 2015...SENSORS FOR DEAD RECKONING, HEADING REFERENCE, OBSTACLE DETECTION, AND OBSTACLE AVOIDANCE 5. FUNDING NUMBERS 6. AUTHOR(S) Nejah, Tarek M. 7...DISTRIBUTION CODE 13. ABSTRACT (maximum 200 words) A novel approach for dead reckoning, heading reference, obstacle detection, and obstacle

Gait development on Minitaur, a direct drive quadrupedal robot

NASA Astrophysics Data System (ADS)

Blackman, Daniel J.; Nicholson, John V.; Ordonez, Camilo; Miller, Bruce D.; Clark, Jonathan E.

2016-05-01

This paper describes the development of a dynamic, quadrupedal robot designed for rapid traversal and interaction in human environments. We explore improvements to both physical and control methods to a legged robot (Minitaur) in order to improve the speed and stability of its gaits and increase the range of obstacles that it can overcome, with an eye toward negotiating man-made terrains such as stairs. These modifications include an analysis of physical compliance, an investigation of foot and leg design, and the implementation of ground and obstacle contact sensing for inclusion in the control schemes. Structural and mechanical improvements were made to reduce undesired compliance for more consistent agreement with dynamic models, which necessitated refinement of foot design for greater durability. Contact sensing was implemented into the control scheme for identifying obstacles and deviations in surface level for negotiation of varying terrain. Overall the incorporation of these features greatly enhances the mobility of the dynamic quadrupedal robot and helps to establish a basis for overcoming obstacles.

Identifying and Overcoming Obstacles to Point-of-Care Data Collection for Eye Care Professionals

PubMed Central

Lobach, David F.; Silvey, Garry M.; Macri, Jennifer M.; Hunt, Megan; Kacmaz, Roje O.; Lee, Paul P.

2005-01-01

Supporting data entry by clinicians is considered one of the greatest challenges in implementing electronic health records. In this paper we describe a formative evaluation study using three different methodologies through which we identified obstacles to point-of-care data entry for eye care and then used the formative process to develop and test solutions to overcome these obstacles. The greatest obstacles were supporting free text annotation of clinical observations and accommodating the creation of detailed diagrams in multiple colors. To support free text entry, we arrived at an approach that captures an image of a free text note and associates this image with related data elements in an encounter note. The detailed diagrams included a color pallet that allowed changing pen color with a single stroke and also captured the diagrams as an image associated with related data elements. During observed sessions with simulated patients, these approaches satisfied the clinicians’ documentation needs by capturing the full range of clinical complexity that arises in practice. PMID:16779083

Computer vision techniques for rotorcraft low altitude flight

NASA Technical Reports Server (NTRS)

Sridhar, Banavar

1990-01-01

Rotorcraft operating in high-threat environments fly close to the earth's surface to utilize surrounding terrain, vegetation, or manmade objects to minimize the risk of being detected by an enemy. Increasing levels of concealment are achieved by adopting different tactics during low-altitude flight. Rotorcraft employ three tactics during low-altitude flight: low-level, contour, and nap-of-the-earth (NOE). The key feature distinguishing the NOE mode from the other two modes is that the whole rotorcraft, including the main rotor, is below tree-top whenever possible. This leads to the use of lateral maneuvers for avoiding obstacles, which in fact constitutes the means for concealment. The piloting of the rotorcraft is at best a very demanding task and the pilot will need help from onboard automation tools in order to devote more time to mission-related activities. The development of an automation tool which has the potential to detect obstacles in the rotorcraft flight path, warn the crew, and interact with the guidance system to avoid detected obstacles, presents challenging problems. Research is described which applies techniques from computer vision to automation of rotorcraft navigtion. The effort emphasizes the development of a methodology for detecting the ranges to obstacles in the region of interest based on the maximum utilization of passive sensors. The range map derived from the obstacle-detection approach can be used as obstacle data for the obstacle avoidance in an automatic guidance system and as advisory display to the pilot. The lack of suitable flight imagery data presents a problem in the verification of concepts for obstacle detection. This problem is being addressed by the development of an adequate flight database and by preprocessing of currently available flight imagery. The presentation concludes with some comments on future work and how research in this area relates to the guidance of other autonomous vehicles.

Stepping over obstacles: gait patterns of healthy young and old adults.

PubMed

Chen, H C; Ashton-Miller, J A; Alexander, N B; Schultz, A B

1991-11-01

Falls associated with tripping over an obstacle can be devastating to elderly individuals, yet little is known about the strategies used for stepping over obstacles by either old or young adults. The gait of gender-matched groups of 24 young and 24 old healthy adults (mean ages 22 and 71 years) was studied during a 4 m approach to and while stepping over obstacles of 0, 25, 51, or 152 mm height and in level obstacle-free walking. Optoelectronic cameras and recorders were used to record approach and obstacle crossing speeds as well as bilateral lower extremity kinematic parameters that described foot placement and movement trajectories relative to the obstacle. The results showed that age had no effect on minimum swing foot clearance (FC) over an obstacle. For the 25 mm obstacle, mean FC was 64 mm, or approximately three times that used in level gait; FC increased nonlinearly with obstacle height for all subjects. Although no age differences were found in obstacle-free gait, old adults exhibited a significantly more conservative strategy when crossing obstacles, with slower crossing speed, shorter step length, and shorter obstacle-heel strike distance. In addition, the old adults crossed the obstacle so that it was 10% further forward in their obstacle-crossing step. Although all subjects successfully avoided the riskiest form of obstacle contact, tripping, 4/24 healthy old adults stepped on an obstacle, demonstrating an increased risk for obstacle contact with age.

Why is patient safety so hard in low-income countries? A qualitative study of healthcare workers' views in two African hospitals.

PubMed

Aveling, Emma-Louise; Kayonga, Yvette; Nega, Ansha; Dixon-Woods, Mary

2015-02-25

The views of practitioners at the sharp end of health care provision are now recognised as a valuable source of intelligence that can inform efforts to improve patient safety in high-income countries. Yet despite growing policy emphasis on patient safety in low-income countries, little research examines the views of practitioners in these settings. We aimed to give voice to how healthcare workers in two East African hospitals identify and explain the major obstacles to ensuring the safety of patients in their care. We conducted in-depth, face to face interviews with healthcare workers in two East African hospitals. Our sample included a total of 57 hospital staff, including nurses, physicians, technicians, clinical services staff, administrative staff and hospital managers. Hospital staff in low-income settings offered broadly encompassing and aspirational definitions of patient safety. They identified obstacles to patient safety across three major themes: material context, staffing issues and inter-professional working relationships. Participants distinguished between the proximal influences on patient safety that posed an immediate threat to patient care, and the distal influences that generated the contexts for such hazards. These included contexts of severe material deprivation, but also the impact of relational factors such as teamwork and professional hierarchies. Structures of authority, governance and control that were not optimally aligned with achieving patient safety were widely reported. As in high-income countries, the accounts of healthcare workers in low-income countries provide sophisticated and valuable insights into the challenges of patient safety. Though the impact of resource constraints and weak governance structures are particularly marked in low-income countries, the congruence between accounts of health workers in diverse settings suggest that the origins and solutions to patient safety problems are likely to be similar everywhere and are rooted in human factors, resources, culture and behaviour. While additional resources are essential to patient safety improvement in low-income settings, such resources on their own will not be sufficient to secure the changes needed.

An Evolutionary Framework for Understanding the Origin of Eukaryotes

PubMed Central

Blackstone, Neil W.

2016-01-01

Two major obstacles hinder the application of evolutionary theory to the origin of eukaryotes. The first is more apparent than real—the endosymbiosis that led to the mitochondrion is often described as “non-Darwinian” because it deviates from the incremental evolution championed by the modern synthesis. Nevertheless, endosymbiosis can be accommodated by a multi-level generalization of evolutionary theory, which Darwin himself pioneered. The second obstacle is more serious—all of the major features of eukaryotes were likely present in the last eukaryotic common ancestor thus rendering comparative methods ineffective. In addition to a multi-level theory, the development of rigorous, sequence-based phylogenetic and comparative methods represents the greatest achievement of modern evolutionary theory. Nevertheless, the rapid evolution of major features in the eukaryotic stem group requires the consideration of an alternative framework. Such a framework, based on the contingent nature of these evolutionary events, is developed and illustrated with three examples: the putative intron proliferation leading to the nucleus and the cell cycle; conflict and cooperation in the origin of eukaryotic bioenergetics; and the inter-relationship between aerobic metabolism, sterol synthesis, membranes, and sex. The modern synthesis thus provides sufficient scope to develop an evolutionary framework to understand the origin of eukaryotes. PMID:27128953

Effect of polyvinyl alcohol on in vitro rooting capacity of shoots in pear clones (Pyrus communis L.) of different ploidy

USDA-ARS?s Scientific Manuscript database

Poor adventitious root formation is a major obstacle in micropropagation. In this study, intense efforts have been made for improvement of rooting procedures for triploid, tetraploid, and mixploid clones of the pear cultivar, 'Fertility', obtained by in vitro colchicine treatment. An efficient roo...

A Mixed Method Case Study on Learner Engagement in e-Learning Professional Training

ERIC Educational Resources Information Center

Zhao, Jane Yanfeng

2014-01-01

Previous research showed that learners' reluctance in participating in e-Learning training is a major obstacle in achieving training objectives. This study focused on learners' e-Learning engagement in professional training in the chapter of the American Society for Training and Development (ASTD). The participants were 21 chapter members.…

Child Care and Employed Parents of Children with Emotional or Behavioral Disorders

ERIC Educational Resources Information Center

Rosenzweig, Julie M.; Brennan, Eileen M.; Huffstutter, Katherine; Bradley, Jennifer R.

2008-01-01

Lack of appropriate child care is frequently reported by parents of children with disabilities as a major obstacle to finding and maintaining their employment. Care for children with emotional or behavioral disorders is particularly difficult to locate because child care providers often lack adequate training. Findings are presented from…

Factors Influencing Talent Development: Stories of Four Hong Kong Elite Sportspersons

ERIC Educational Resources Information Center

Chan, Regina; Yuen, Mantak

2013-01-01

This article reports on a small-scale qualitative study that investigates how intrapersonal and environmental factors shape the beliefs and experiences of four talented Hong Kong sportsperons. Research questions focus on how their talents were identified and developed, obstacles they encountered, and the major influences on their development.…

Semantic Categorization: A Comparison between Deaf and Hearing Children

ERIC Educational Resources Information Center

Ormel, Ellen A.; Gijsel, Martine A. R.; Hermans, Daan; Bosman, Anna M. T.; Knoors, Harry; Verhoeven, Ludo

2010-01-01

Learning to read is a major obstacle for children who are deaf. The otherwise significant role of phonology is often limited as a result of hearing loss. However, semantic knowledge may facilitate reading comprehension. One important aspect of semantic knowledge concerns semantic categorization. In the present study, the quality of the semantic…

Administration of kisspeptins accelerates gonadal development and alters gene expression in Moronids

USDA-ARS?s Scientific Manuscript database

The present study assesses the effects of chronic administration of peptides to fish, termed kisspeptins, which are the products of the KISS1 and KISS2 genes, and have been shown to control the development of puberty in animals. In aquaculture, one of the major obstacles to the commercial production...

Characterizing the Role of the Public Librarian: A Survey.

ERIC Educational Resources Information Center

Flatley, Robert

2000-01-01

Examines how rural librarians view librarianship and libraries, and the future of both. A total of 441 surveys were sent out; 232 were analyzed. Findings indicate rural librarians are overwhelmingly positive about the profession and its future. The major obstacle facing rural libraries is a lack of education to cope with changes the information…

The Relevance of English in Colombian Scientific Research Awareness

ERIC Educational Resources Information Center

Cortés, Jimy Alexander; Arellano, Iván Darío

2017-01-01

Even though the majority of Colombian professors are also involved in research, they have limitations in their English language skills that separate them from the rest of the scientific society. Evidently, these limitations have become an obstacle in the awareness of professors' modest, but no less important, research work. In order to carry out…

Statistical Properties of Differences between Low and High Resolution CMAQ Runs with Matched Initial and Boundary Conditions

EPA Science Inventory

The difficulty in assessing errors in numerical models of air quality is a major obstacle to improving their ability to predict and retrospectively map air quality. In this paper, using simulation outputs from the Community Multi-scale Air Quality Model (CMAQ), the statistic...

A review of apple anthracnose canker biology and management in cider apple orchards in the Maritime Pacific Northwest

USDA-ARS?s Scientific Manuscript database

Cider apple (Malus ×domestica Borkh.) is an emerging crop in western Washington and the Pacific Northwest (PNW) region, but a major obstacle to planting new orchards and orchard productivity is the widespread occurrence of apple anthracnose canker, caused by the fungal pathogen Neofabraea malicortic...

Continuing Education in Massachusetts; State Programs for the Seventies.

ERIC Educational Resources Information Center

Levin, Melvin R.; Slavet, Joseph S.

Varying needs, largely unmet, were found in the provision of adult education throughout Massachusetts, and recommendations were formulated for an articulated and adequate program. Low priority, weak centers of leadership, and a limited and confused mandate emerged as major obstacles to effectiveness. It was found that, on the basis of accepted…

Gene Flow in Genetically Engineered Perennial Grasses: Lessons for Modification of Dedicated Bioenergy Crops

USDA-ARS?s Scientific Manuscript database

Genetic modification of dedicated bioenergy crops, such as switchgrass, will play a major role in crop improvement for a wide range of beneficial traits specific to biofuels. One obstacle that arises regarding transgenic improvement of perennials used for biofuels is the propensity of these plants t...

The Marginal Majority: Women War Correspondents in the Salvadoran Press Corps Association (SPCA).

ERIC Educational Resources Information Center

Pedelty, Mark

1997-01-01

Finds that men in the Salvadoran Press Corps Association used Hemingwayesque myths and ritual performances which dominated corps culture to escape the discipline of corporate press institutions, while women correspondents experienced the rituals as an obstacle to individual and collective attempts to negotiate or reform the field. Analyses gender…

Development of Three-Tier Heat, Temperature and Internal Energy Diagnostic Test

ERIC Educational Resources Information Center

Gurcay, Deniz; Gulbas, Etna

2015-01-01

Background: Misconceptions are major obstacles to learning physics, and the concepts of heat and temperature are some of the common misconceptions that are encountered in daily life. Therefore, it is important to develop valid and reliable tools to determine students' misconceptions about basic thermodynamics concepts. Three-tier tests are…

Demonstration Project on Developing Alternative Qualifications and Credentials for Paraprofessionals. Phase II. July 1970-December 1973. Final Report.

ERIC Educational Resources Information Center

Lesh, Seymour; And Others

This demonstration aims at eliminating major obstacles blocking career advancement of human service paraprofessionals. It seeks to develop new options for upgrading workers in four occupations: addiction services, child development, occupational therapy, and teaching. The policies and practices of educational institutions, employers, unions,…

Using copper sulfate on hybrid striped bass eggs to control fungus and increase survival

USDA-ARS?s Scientific Manuscript database

A major obstacle in fish hatcheries is the inevitable fungal growth on eggs. Copper sulfate (CuSO4) is commonly used for fungus control in channel catfish hatcheries that use troughs, but effectiveness on fish eggs hatched using different systems has only recently been investigated. Fish were spawn...

Extracts from: Analysis of Selected Economic Factors Influencing Franco-Albertan Education

ERIC Educational Resources Information Center

Liguori, George T.

1978-01-01

An examination of selected economic factors most likely to influence the income level of Francophones in Alberta. It focuses on occupation, education level, sex, geographical areas, income and source of income. Evidence indicates that educational level and slow rate of urbanization are major obstacles to more equitable distribution of wealth. (AMH)

Democracy's Untold Story: What World History Textbooks Neglect.

ERIC Educational Resources Information Center

Gagnon, Paul

Content weakness in textbooks is a major obstacle to effective social studies teaching. Chapters 1-3 of this book provide the Education for Democracy Project's Statement of Principles, a consideration of history's role as the core of social studies education, and the role of textbooks in teaching world history. Chapters 4-14 examine five selected…

Changing Our Minds: The Struggle To Generate a Humanistic Neuroscience Language through Metaphors from Quantum Physics.

ERIC Educational Resources Information Center

Liston, Delores D.

While the physiological explanations from neuroscience help explain the mechanisms of learning, they fall short of explaining the sociocultural and phenomenological factors that determine a stressful versus a challenging interpretation of experience. For this reason, neuroscience seems less than useful to classroom teachers. A major obstacle in…

The Importance of Infrastructure Development to High-Quality Literacy Instruction

ERIC Educational Resources Information Center

Cohen, David K.; Bhatt, Monica P.

2012-01-01

Although the education community has identified numerous effective interventions for improving the literacy of U.S. schoolchildren, little headway has been made in raising literacy capabilities. David K. Cohen and Monica P. Bhatt, of the University of Michigan, contend that a major obstacle is the organizational structure of the U.S. education…

Administrative Obstacles to Technology Use in West Virginia Public Schools: A Survey of West Virginia Principals

ERIC Educational Resources Information Center

Agnew, David W.

2011-01-01

Public school principals must meet many challenges and make decisions concerning financial obligations while providing the best learning environment for students. A major challenge to principals is implementing technological components successfully while providing teachers the 21st century instructional skills needed to enhance students'…

Internships: The Key to Career Preparation, Professional Development, and Career Advancement

ERIC Educational Resources Information Center

Hurst, Jessica L.; Thye, Ann; Wise, Chris Leiran

2014-01-01

In today's competitive job market, students who lack real-world experience face major obstacles. Many professional positions require previous experience; therefore, relevant work experience is a key attribute that any entry-level family and consumer Sciences (FCS) professional can offer a potential employer. Internships provide one of the…

Elementary EFL Teachers' Computer Phobia and Computer Self-Efficacy in Taiwan

ERIC Educational Resources Information Center

Chen, Kate Tzuching

2012-01-01

The advent and application of computer and information technology has increased the overall success of EFL teaching; however, such success is hard to assess, and teachers prone to computer avoidance face negative consequences. Two major obstacles are high computer phobia and low computer self-efficacy. However, little research has been carried out…

Killing of tumor cells: a drama in two acts.

PubMed

Giansanti, Vincenzo; Tillhon, Micol; Mazzini, Giuliano; Prosperi, Ennio; Lombardi, Paolo; Scovassi, A Ivana

2011-11-15

Cancer still represents a major health problem worldwide, which urges the development of more effective strategies. Resistance to chemotherapy, a major obstacle for cancer eradication, is mainly related to an intrinsic failure to activate the apoptotic pathways. However, a protective effect of autophagy toward cancer cells has been recently observed, thus adding further complexity to the development of an effective approach counteracting cancer cell growth and improving the response to therapy. Copyright © 2011 Elsevier Inc. All rights reserved.

Innovative research of AD HOC network mobility model

NASA Astrophysics Data System (ADS)

Chen, Xin

2017-08-01

It is difficult for researchers of AD HOC network to conduct actual deployment during experimental stage as the network topology is changeable and location of nodes is unfixed. Thus simulation still remains the main research method of the network. Mobility model is an important component of AD HOC network simulation. It is used to describe the movement pattern of nodes in AD HOC network (including location and velocity, etc.) and decides the movement trail of nodes, playing as the abstraction of the movement modes of nodes. Therefore, mobility model which simulates node movement is an important foundation for simulation research. In AD HOC network research, mobility model shall reflect the movement law of nodes as truly as possible. In this paper, node generally refers to the wireless equipment people carry. The main research contents include how nodes avoid obstacles during movement process and the impacts of obstacles on the mutual relation among nodes, based on which a Node Self Avoiding Obstacle, i.e. NASO model is established in AD HOC network.

Scanning angle Raman spectroscopy: Investigation of Raman scatter enhancement techniques for chemical analysis

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

Meyer, Matthew W.

2013-01-01

This thesis outlines advancements in Raman scatter enhancement techniques by applying evanescent fields, standing-waves (waveguides) and surface enhancements to increase the generated mean square electric field, which is directly related to the intensity of Raman scattering. These techniques are accomplished by employing scanning angle Raman spectroscopy and surface enhanced Raman spectroscopy. A 1064 nm multichannel Raman spectrometer is discussed for chemical analysis of lignin. Extending dispersive multichannel Raman spectroscopy to 1064 nm reduces the fluorescence interference that can mask the weaker Raman scattering. Overall, these techniques help address the major obstacles in Raman spectroscopy for chemical analysis, which include themore » inherently weak Raman cross section and susceptibility to fluorescence interference.« less

Neem Oil and Crop Protection: From Now to the Future

PubMed Central

Campos, Estefânia V. R.; de Oliveira, Jhones L.; Pascoli, Mônica; de Lima, Renata; Fraceto, Leonardo F.

2016-01-01

A major challenge of agriculture is to increase food production to meet the needs of the growing world population, without damaging the environment. In current agricultural practices, the control of pests is often accomplished by means of the excessive use of agrochemicals, which can result in environmental pollution and the development of resistant pests. In this context, biopesticides can offer a better alternative to synthetic pesticides, enabling safer control of pest populations. However, limitations of biopesticides, including short shelf life, photosensitivity, and volatilization, make it difficult to use them on a large scale. Here, we review the potential use of neem oil in crop protection, considering the gaps and obstacles associated with the development of sustainable agriculture in the not too distant future. PMID:27790224

Neem Oil and Crop Protection: From Now to the Future.

PubMed

Campos, Estefânia V R; de Oliveira, Jhones L; Pascoli, Mônica; de Lima, Renata; Fraceto, Leonardo F

2016-01-01

A major challenge of agriculture is to increase food production to meet the needs of the growing world population, without damaging the environment. In current agricultural practices, the control of pests is often accomplished by means of the excessive use of agrochemicals, which can result in environmental pollution and the development of resistant pests. In this context, biopesticides can offer a better alternative to synthetic pesticides, enabling safer control of pest populations. However, limitations of biopesticides, including short shelf life, photosensitivity, and volatilization, make it difficult to use them on a large scale. Here, we review the potential use of neem oil in crop protection, considering the gaps and obstacles associated with the development of sustainable agriculture in the not too distant future.

Unraveling the Mystery of Exozodiacal Dust

NASA Astrophysics Data System (ADS)

Ertel, S.; Augereau, J.-C.; Thébault, P.; Absil, O.; Bonsor, A.; Defrère, D.; Kral, Q.; Le Bouquin, J.-B.; Lebreton, J.; Coudé du Foresto, V.

2014-01-01

Exozodiacal dust clouds are thought to be the extrasolar analogs of the Solar System's zodiacal dust. Studying these systems provides insights in the architecture of the innermost regions of planetary systems, including the Habitable Zone. Furthermore, the mere presence of the dust may result in major obstacles for direct imaging of earth-like planets. Our EXOZODI project aims to detect and study exozodiacal dust and to explain its origin. We are carrying out the first large, near-infrared interferometric survey in the northern (CHARA/FLUOR) and southern (VLTI/PIONIER) hemispheres. Preliminary results suggest a detection rate of up to 30% around A to K type stars and interesting trends with spectral type and age. We focus here on presenting the observational work carried out by our team.

Gabon.

PubMed

1988-07-01

The country of Gabon straddles the equator on the west coast of Africa. Included in the document are brief descriptions and compilations of facts about such points as geography, people, history, type of government, political conditions, economy, foreign relations, defense, and US-Gabonese relations. The population in 1986 was estimated at 1 million, and the annual growth rate was 2.8%. Infant mortality rate is 159/1000. Life expectancy stands at 51 years. Hospitals and private clinics are available throughout most of the country for most common problems. Gabon's population declined between 1900 and 1940 as a result of a combination of historical and environmental factors. The country is one of the less densely inhabited in Africa, and a labor shortage is a major obstacle to its development.

The effects of multiple obstacles on the locomotor behavior and performance of a terrestrial lizard.

PubMed

Parker, Seth E; McBrayer, Lance D

2016-04-01

Negotiation of variable terrain is important for many small terrestrial vertebrates. Variation in the running surface resulting from obstacles (woody debris, vegetation, rocks) can alter escape paths and running performance. The ability to navigate obstacles likely influences survivorship through predator evasion success and other key ecological tasks (finding mates, acquiring food). Earlier work established that running posture and sprint performance are altered when organisms face an obstacle, and yet studies involving multiple obstacles are limited. Indeed, some habitats are cluttered with obstacles, whereas others are not. For many species, obstacle density may be important in predator escape and/or colonization potential by conspecifics. This study examines how multiple obstacles influence running behavior and locomotor posture in lizards. We predict that an increasing number of obstacles will increase the frequency of pausing and decrease sprint velocity. Furthermore, bipedal running over multiple obstacles is predicted to maintain greater mean sprint velocity compared with quadrupedal running, thereby revealing a potential advantage of bipedalism. Lizards were filmed running through a racetrack with zero, one or two obstacles. Bipedal running posture over one obstacle was significantly faster than quadrupedal posture. Bipedal running trials contained fewer total strides than quadrupedal ones. But on addition of a second obstacle, the number of bipedal strides decreased. Increasing obstacle number led to slower and more intermittent locomotion. Bipedalism provided clear advantages for one obstacle, but was not associated with further benefits for an additional obstacle. Hence, bipedalism helps mitigate obstacle negotiation, but not when numerous obstacles are encountered in succession. © 2016. Published by The Company of Biologists Ltd.

Rural Emergency Nurses' Suggestions for Improving End-of-Life Care.

PubMed

Beckstrand, Renea L; Smith, Kelly E; Luthy, Karlen E Beth; Macintosh, Janelle L B

2017-05-01

Many patient visits to emergency departments result in the patient dying or being pronounced dead on arrival. The numbers of deaths in emergency departments are likely to increase as a significant portion of the U.S. population ages. Consequently, emergency nurses face many obstacles to providing quality end-of-life (EOL) care when death occurs. The purpose of this study was to identify suggestions that emergency nurses have to improve EOL care, specifically in rural emergency departments. A 57-item questionnaire was sent to 53 rural hospitals in 4 states in the Intermountain West, plus Alaska. One item asked nurses to identify the one aspect of EOL care they would change for dying patients in rural emergency departments. Each qualitative response was individually reviewed by a research team and then coded into a theme. Four major themes and three minor themes were identified. The major themes were providing greater privacy during EOL care for patients and family members, increasing availability of support services, additional staffing, and improved staff and community education. Providing adequate privacy for patients and family members was a major obstacle to providing EOL care in the emergency department, largely because of poor department design, especially in rural emergency departments where space is limited. Lack of support services and adequate staffing were also obstacles to providing quality EOL care in rural emergency departments. Consequently, rural nurses are commonly pulled away from EOL care to perform ancillary duties because additional support personnel are lacking. Providing EOL care in rural emergency departments is a challenging task given the limited staffing and resources, and thus it is imperative that nurses' suggestions for improvement of EOL care be acknowledged. Because of the current lack of research in rural EOL care, additional research is needed. Copyright © 2015 Emergency Nurses Association. Published by Elsevier Inc. All rights reserved.

Atmospheric dispersion of a heavier-than-air gas near a two-dimensional obstacle

NASA Astrophysics Data System (ADS)

Sutton, S. B.; Brandt, H.; White, B. R.

1986-04-01

Flow over a two-dimensional obstacle and dispersion of a heavier-than-air gas near the obstacle were studied. Two species, one representing air and the other representing the heavier-than-air gas were treated. Equations for mass and momentum were cast in mass-averaged form, with turbulent Reynolds stresses and mass fluxes modeled using eddy-viscosity and diffusivity hypotheses. A two-equation k-ɛ turbulence model was used to determine the effective turbulent viscosity. Streamline curvature and buoyancy corrections were added to the basic turbulence formulation. The model equations were solved using finite difference techniques. An alternating-direction-implicit (ADI) technique was used to solve the parabolic transport equations and a direct matrix solver was used to solve the elliptic pressure equation. Mesh sensitivities were investigated to determine the optimum mesh requirements for the final calculations. It was concluded that at least 10 grid spaces were required across the obstacle width and 15 across the obstacle height to obtain valid solutions. A non-uniform mesh was used to concentrate the grid points at the top of the obstacle. Experimental measurements were made with air flow over a 7.6 by 7.6 cm obstacle in a boundary-layer wind tunnel. Smoke visualization revealed a low-frequency oscillation of the bubble downstream of the obstacle. Hot-wire anemometer data are presented for the mean velocity and turbulent kinetic energy at the mid-plane of the obstacle and the mid-plane of the downstream recirculation bubble. A single hot-wire probe was found to be suitable for determining mean streamwise velocities with an accuracy of 11 %. The downstream recirculation bubble was unsteady and had a length range from 3 to 8 obstacle lengths. The experimental results for flow over the obstacle were compared with numerical calculations to validate the numerical solution procedure. A sensitivity study on the effect of curvature correction and variation of turbulence model constants on the numerical solution was conducted. Calculations that included the curvature correction model gave a downstream recirculation bubble length of 5.9 obstacle lengths while excluding the correction reduced this length to 4.4. In the second part of the study, numerical calculations were performed for the dispersion of a heavier-than-air gas in the vicinity of the two-dimensional obstacle. Characteristics of an adiabatic boundary layer were used in these calculations. The densities of the contaminant gases were 0, 25 and 50% greater than the air density. Calculations were performed with the contaminant injection source upstream and downstream of the obstacle. Use of the pressure gradient model reduced the size of the dense gas cloud by as much as 12%. The curvature correction model also affected the cloud expanse by reducing the effective turbulent viscosity in the downstream recirculation bubble. The location of the injection source had the largest impact on the cloud size. The area of the cloud within the 5 % contour was three times larger for downstream injection than for upstream injection.

Ethical and methodological issues in academic mental health research in populations affected by disasters: the Oklahoma City experience relevant to September 11, 2001.

PubMed

North, Carol S; Pfefferbaum, Betty; Tucker, Phebe

2002-08-01

Empirical data from research studies are vital to guiding mental health interventions following disasters. However, few data are available for this purpose. Important advances in policy and procedures for the conduct of organized research emerged from the Oklahoma City bombing, yielding cooperative working relationships among researchers and culminating in the ethical attainment of informative research data. However, the academic community was again caught off guard after the September 11, 2001, terrorist attacks. Suggestions to surmount these obstacles include incorporating research infrastructures into disaster preparedness plans in advance; organizing the community of researchers; and working closely with major funding organizations. Methodological issues pertaining to measurement of psychopathology include the importance of obtaining diagnostic data; interpreting the meaning of symptoms in the absence of a psychiatric disorder; differentiating preexisting symptoms from those that emerged after the disaster, and optimal timing of postdisaster assessment.

Challenges and strategies for quantitative and qualitative field research in the United Arab Emirates.

PubMed

Aw, Tar-Ching; Zoubeidi, Taoufik; Al-Maskari, Fatma; Blair, Iain

2011-01-01

Clinical and public health research depends on factors including national systems, socio-cultural influences, and access to organisations and individuals. As a 'new' country, the United Arab Emirates (UAE) has yet to develop strong support for population research. However, there is interest in research. The challenges for quantitative and qualitative research include the varied composition and mobility of the UAE population, with limited health records and disease registries. Long-term follow-up of patients, and tracing foreign workers who may only be in the UAE for a few years, are two major obstacles for longitudinal studies. There can also be a reluctance shown by parts of the population to participate in studies, especially those that require responding to what is perceived as sensitive questions. Successful execution of population research in the UAE requires an understanding of socio-cultural aspects of the study population, and good communication between researchers and participants.

Commercialisation of Biomarker Tests for Mental Illnesses: Advances and Obstacles.

PubMed

Chan, Man K; Cooper, Jason D; Bahn, Sabine

2015-12-01

Substantial strides have been made in the field of biomarker research for mental illnesses over the past few decades. However, no US FDA-cleared blood-based biomarker tests have been translated into routine clinical practice. Here, we review the challenges associated with commercialisation of research findings and discuss how these challenges can impede scientific impact and progress. Overall evidence indicates that a lack of research funding and poor reproducibility of findings were the most important obstacles to commercialization of biomarker tests. Fraud, pre-analytical and analytical limitations, and inappropriate statistical analysis are major contributors to poor reproducibility. Increasingly, these issues are acknowledged and actions are being taken to improve data validity, raising the hope that robust biomarker tests will become available in the foreseeable future. Copyright © 2015 Elsevier Ltd. All rights reserved.

Adoptive T cell therapy: An overview of obstacles and opportunities.

PubMed

Baruch, Erez Nissim; Berg, Amy Lauren; Besser, Michal Judith; Schachter, Jacob; Markel, Gal

2017-06-01

The therapeutic potential of adoptive cell therapy (ACT) in cancer patients was first acknowledged 3 decades ago, but it was an esoteric approach at the time. In recent years, technological advancements have transformed ACT into a viable therapeutic option that can be curative in some patients. In fact, current ACT response rates are 80% to 90% for hematological malignancies and 30% for metastatic melanoma refractory to multiple lines of therapy. Although these results are encouraging, there is still much to be done to fulfill ACT's potential, specifically with regard to improving clinical efficacy, expanding clinical indications, reducing toxicity, and increasing production and cost-effectiveness. This review addresses the current major obstacles to ACT and presents potential solutions. Cancer 2017;123:2154-62. © 2017 American Cancer Society. © 2017 American Cancer Society.

Evaluation of Mental Workload among ICU Ward's Nurses

PubMed Central

Mohammadi, Mohsen; Mazloumi, Adel; Kazemi, Zeinab; Zeraati, Hojat

2015-01-01

Background: High level of workload has been identified among stressors of nurses in intensive care units (ICUs). The present study investigated nursing workload and identified its influencing perfor­mance obstacles in ICUs. Methods: This cross-sectional study was conducted, in 2013, on 81 nurses working in ICUs in Imam Khomeini Hospital in Tehran, Iran. NASA-TLX was applied for assessment of workload. Moreover, ICUs Performance Obstacles Questionnaire was used to identify performance obstacles associated with ICU nursing. Results: Physical demand (mean=84.17) was perceived as the most important dimensions of workload by nurses. The most critical performance obstacles affecting workload included: difficulty in finding a place to sit down, hectic workplace, disorganized workplace, poor-conditioned equipment, waiting for using a piece of equipment, spending much time seeking for supplies in the central stock, poor quality of medical materials, delay in getting medications, unpredicted problems, disorganized central stock, outpatient surgery, spending much time dealing with family needs, late, inadequate, and useless help from nurse assistants, and ineffective morning rounds (P-value<0.05). Conclusion: Various performance obstacles are correlated with nurses' workload, affirms the significance of nursing work system characteristics. Interventions are recommended based on the results of this study in the work settings of nurses in ICUs. PMID:26933647

Flow through a very porous obstacle in a shallow channel

PubMed Central

Draper, S.; Nishino, T.; Borthwick, A. G. L.

2017-01-01

A theoretical model, informed by numerical simulations based on the shallow water equations, is developed to predict the flow passing through and around a uniform porous obstacle in a shallow channel, where background friction is important. This problem is relevant to a number of practical situations, including flow through aquatic vegetation, the performance of arrays of turbines in tidal channels and hydrodynamic forces on offshore structures. To demonstrate this relevance, the theoretical model is used to (i) reinterpret core flow velocities in existing laboratory-based data for an array of emergent cylinders in shallow water emulating aquatic vegetation and (ii) reassess the optimum arrangement of tidal turbines to generate power in a tidal channel. Comparison with laboratory-based data indicates a maximum obstacle resistance (or minimum porosity) for which the present theoretical model is valid. When the obstacle resistance is above this threshold the shallow water equations do not provide an adequate representation of the flow, and the theoretical model over-predicts the core flow passing through the obstacle. The second application of the model confirms that natural bed resistance increases the power extraction potential for a partial tidal fence in a shallow channel and alters the optimum arrangement of turbines within the fence. PMID:28484321

Obstacles to the coordination of delivering integrated prenatal HIV, syphilis and hepatitis B testing services in Guangdong: using a needs assessment approach.

PubMed

Xia, Jianhong; Rutherford, Shannon; Ma, Yuanzhu; Wu, Li; Gao, Shuang; Chen, Tingting; Lu, Xiao; Zhang, Xiaozhuang; Chu, Cordia

2015-03-24

Integration of services for Prevention of Mother-To-Child Transmission of HIV (PMTCT) into routine maternal and child health care is promoted as a priority strategy by the WHO to facilitate the implementation of PMTCT. Integration of services emphasizes inter-sectoral coordination in the health systems to provide convenient services for clients. China has been integrating prenatal HIV, syphilis and hepatitis B testing services since 2009. However, as the individual health systems are complex, effective coordination among different health agencies is challenging. Few studies have examined the factors that affect the coordination of such complex systems. The aim of this study is to assess the effectiveness of and examine challenges for integrated service delivery. Findings will provide the basis for strategy development to enhance the effective delivery of integrated services. The research was conducted in Guangdong province in 2013 using a needs assessment approach that includes qualitative and quantitative methods. Quantitative data was collected through a survey and from routine monitoring for PMTCT and qualitative data was collected through stakeholder interviews. Routine monitoring data used to assess key indicators of coordination suggested numerous coordination problems. The rates of prenatal HIV (95%), syphilis (47%) and hepatitis B (47%) test were inconsistent. An average of only 20% of the HIV positive mothers was referred in the health systems. There were no regular meetings among different health agencies and the clients indicated complicated service processes. The major obstacles to the coordination of delivering these integrated services are lack of service resource integration; and lack of a mechanism for coordination of the health systems, with no uniform guidelines, clear roles or consistent evaluation. The key obstacles that have been identified in this study hinder the coordination of the delivery of integrated services. Our recommendations include: 1) Facilitate integration of the funding and information systems by fully combining the service resources of different health agencies into one unit; 2) Establish regular meetings to facilitate exchange of information and address problems; 3) Establish a client referral network between different health agencies with agreed guidelines, clear roles and consistent evaluation.

Current practice of liquid chromatography-mass spectrometry in metabolomics and metabonomics.

PubMed

Gika, Helen G; Theodoridis, Georgios A; Plumb, Robert S; Wilson, Ian D

2014-01-01

Based on publication and citation numbers liquid chromatography (LC-MS) has become the major analytical technology in the field of global metabolite profiling. This dominance reflects significant investments from both the research community and instrument manufacturers. Here an overview of the approaches taken for LC-MS-based metabolomics research is given, describing critical steps in the realisation of such studies: study design and its needs, specific technological problems to be addressed and major obstacles in data treatment and biomarker identification. The current state of the art for LC-MS-based analysis in metabonomics/metabolomics is described including recent developments in liquid chromatography, mass spectrometry and data treatment as these are applied in metabolomics underlining the challenges, limitations and prospects for metabolomics research. Examples of the application of metabolite profiling in the life sciences focusing on disease biomarker discovery are highlighted. In addition, new developments and future prospects are described. Copyright © 2013 Elsevier B.V. All rights reserved.

Competing English, Spanish, and French alabaster trade in Europe over five centuries as evidenced by isotope fingerprinting

PubMed Central

Kloppmann, W.; Leroux, L.; Bromblet, P.; Le Pogam, P.-Y.; Cooper, A. H.; Worley, N.; Guerrot, C.; Montech, A. T.; Gallas, A. M.; Aillaud, R.

2017-01-01

A lack of written sources is a serious obstacle in the reconstruction of the medieval trade of art and art materials, and in the identification of artists, workshop locations, and trade routes. We use the isotopes of sulfur, oxygen, and strontium (S, O, Sr) present in gypsum alabaster to unambiguously link ancient European source quarries and areas to alabaster artworks produced over five centuries (12th–17th) held by the Louvre museum in Paris and other European and American collections. Three principal alabaster production areas are identified, in central England, northern Spain, and a major, long-lived but little-documented alabaster trade radiating from the French Alps. The related trade routes are mostly fluvial, although terrestrial transport crossing the major river basin borders is also confirmed by historical sources. Our study also identifies recent artwork restoration using Italian alabaster and provides a robust geochemical framework for provenancing, including recognition of restoration and forgeries. PMID:29078309

Imaging the pathophysiology of major depressive disorder - from localist models to circuit-based analysis

PubMed Central

2014-01-01

The neuroimaging literature of Major Depressive Disorder (MDD) has grown substantially over the last several decades, facilitating great advances in the identification of specific brain regions, neurotransmitter systems and networks associated with depressive illness. Despite this progress, fundamental questions remain about the pathophysiology and etiology of MDD. More importantly, this body of work has yet to directly influence clinical practice. It has long been a goal for the fields of clinical psychology and psychiatry to have a means of making objective diagnoses of mental disorders. Frustratingly little movement has been achieved on this front, however, and the 'gold-standard’ of diagnostic validity and reliability remains expert consensus. In light of this challenge, the focus of the current review is to provide a critical summary of key findings from different neuroimaging approaches in MDD research, including structural, functional and neurochemical imaging studies. Following this summary, we discuss some of the current conceptual obstacles to better understanding the pathophysiology of depression, and conclude with recommendations for future neuroimaging research. PMID:24606595

Competing English, Spanish, and French alabaster trade in Europe over five centuries as evidenced by isotope fingerprinting.

PubMed

Kloppmann, W; Leroux, L; Bromblet, P; Le Pogam, P-Y; Cooper, A H; Worley, N; Guerrot, C; Montech, A T; Gallas, A M; Aillaud, R

2017-11-07

A lack of written sources is a serious obstacle in the reconstruction of the medieval trade of art and art materials, and in the identification of artists, workshop locations, and trade routes. We use the isotopes of sulfur, oxygen, and strontium (S, O, Sr) present in gypsum alabaster to unambiguously link ancient European source quarries and areas to alabaster artworks produced over five centuries (12th-17th) held by the Louvre museum in Paris and other European and American collections. Three principal alabaster production areas are identified, in central England, northern Spain, and a major, long-lived but little-documented alabaster trade radiating from the French Alps. The related trade routes are mostly fluvial, although terrestrial transport crossing the major river basin borders is also confirmed by historical sources. Our study also identifies recent artwork restoration using Italian alabaster and provides a robust geochemical framework for provenancing, including recognition of restoration and forgeries. Copyright © 2017 the Author(s). Published by PNAS.

Competing English, Spanish, and French alabaster trade in Europe over five centuries as evidenced by isotope fingerprinting

NASA Astrophysics Data System (ADS)

Kloppmann, W.; Leroux, L.; Bromblet, P.; Le Pogam, P.-Y.; Cooper, A. H.; Worley, N.; Guerrot, C.; Montech, A. T.; Gallas, A. M.; Aillaud, R.

2017-11-01

A lack of written sources is a serious obstacle in the reconstruction of the medieval trade of art and art materials, and in the identification of artists, workshop locations, and trade routes. We use the isotopes of sulfur, oxygen, and strontium (S, O, Sr) present in gypsum alabaster to unambiguously link ancient European source quarries and areas to alabaster artworks produced over five centuries (12th–17th) held by the Louvre museum in Paris and other European and American collections. Three principal alabaster production areas are identified, in central England, northern Spain, and a major, long-lived but little-documented alabaster trade radiating from the French Alps. The related trade routes are mostly fluvial, although terrestrial transport crossing the major river basin borders is also confirmed by historical sources. Our study also identifies recent artwork restoration using Italian alabaster and provides a robust geochemical framework for provenancing, including recognition of restoration and forgeries.

Occupancy change detection system and method

DOEpatents

Bruemmer, David J [Idaho Falls, ID; Few, Douglas A [Idaho Falls, ID

2009-09-01

A robot platform includes perceptors, locomotors, and a system controller. The system controller executes instructions for producing an occupancy grid map of an environment around the robot, scanning the environment to generate a current obstacle map relative to a current robot position, and converting the current obstacle map to a current occupancy grid map. The instructions also include processing each grid cell in the occupancy grid map. Within the processing of each grid cell, the instructions include comparing each grid cell in the occupancy grid map to a corresponding grid cell in the current occupancy grid map. For grid cells with a difference, the instructions include defining a change vector for each changed grid cell, wherein the change vector includes a direction from the robot to the changed grid cell and a range from the robot to the changed grid cell.

Prefrontal cortex activation during obstacle negotiation: What's the effect size and timing?

PubMed

Maidan, Inbal; Shustak, Shiran; Sharon, Topaz; Bernad-Elazari, Hagar; Geffen, Nimrod; Giladi, Nir; Hausdorff, Jeffrey M; Mirelman, Anat

2018-04-01

Obstacle negotiation is a daily activity that requires the integration of sensorimotor and cognitive information. Recent studies provide evidence for the important role of prefrontal cortex during obstacle negotiation. We aimed to explore the effects of obstacle height and available response time on prefrontal activation. Twenty healthy young adults (age: 30.1 ± 1.0 years; 50% women) walked in an obstacle course while negotiating anticipated and unanticipated obstacles at heights of 50 mm and 100 mm. Prefrontal activation was measured using a functional near-infrared spectroscopy system. Kinect cameras measured the obstacle negotiation strategy. Prefrontal activation was defined based on mean level of HbO 2 before, during and after obstacle negotiation and the HbO 2 slope from gait initiation and throughout the task. Changes between types of obstacles were assessed using linear-mix models and partial correlation analyses evaluated the relationship between prefrontal activation and the distance between the feet as the subjects traversed the obstacles. Different obstacle heights showed similar changes in prefrontal activation measures (p > 0.210). However, during unanticipated obstacles, the slope of the HbO 2 response was steeper (p = 0.048), as compared to anticipated obstacles. These changes in prefrontal activation during negotiation of unanticipated obstacles were correlated with greater distance of the leading foot after the obstacles (r = 0.831, p = 0.041). These findings are the first to show that the pattern of prefrontal activation depends on the nature of the obstacle. More specifically, during unanticipated obstacles the recruitment of the prefrontal cortex is faster and greater than during negotiating anticipated obstacles. These results provide evidence of the important role of the prefrontal cortex and the ability of healthy young adults to tailor the activation pattern to different types of obstacles. Copyright © 2018 Elsevier Inc. All rights reserved.

Multiple-camera/motion stereoscopy for range estimation in helicopter flight

NASA Technical Reports Server (NTRS)

Smith, Phillip N.; Sridhar, Banavar; Suorsa, Raymond E.

1993-01-01

Aiding the pilot to improve safety and reduce pilot workload by detecting obstacles and planning obstacle-free flight paths during low-altitude helicopter flight is desirable. Computer vision techniques provide an attractive method of obstacle detection and range estimation for objects within a large field of view ahead of the helicopter. Previous research has had considerable success by using an image sequence from a single moving camera to solving this problem. The major limitations of single camera approaches are that no range information can be obtained near the instantaneous direction of motion or in the absence of motion. These limitations can be overcome through the use of multiple cameras. This paper presents a hybrid motion/stereo algorithm which allows range refinement through recursive range estimation while avoiding loss of range information in the direction of travel. A feature-based approach is used to track objects between image frames. An extended Kalman filter combines knowledge of the camera motion and measurements of a feature's image location to recursively estimate the feature's range and to predict its location in future images. Performance of the algorithm will be illustrated using an image sequence, motion information, and independent range measurements from a low-altitude helicopter flight experiment.

Co-management of Water, Energy, and Food Systems: Where Are We and What Does it Take for Implementation?

NASA Astrophysics Data System (ADS)

Akhbari, M.

2015-12-01

Water, energy, and food are closely bound in consumption and production patterns. To increase resource efficiency and productivity in a sustainable fashion, co-management of water, energy, and food resources is becoming inevitable. These co-management schemes require implementation of nexus-based approaches, which takes the interconnections of water, energy, and food systems into account and considers that development in one area may have major effects on others. While society, economy and environment are the action areas to implement a nexus approach, finance, governance, infrastructure and technology can create solutions. Existing obstacles in the action areas and challenges associated with creating solutions increase the complexities to develop nexus-based approaches and complicate their implementation. This study, identifies existing social, economic, and environmental obstacles, financial demands and constraints, shortcomings in governance, and infrastructure problems in the United States as the main challenges that need to be overcome. Then, it will be discussed how advanced technology could be employed to facilitate implementation of nexus-based approaches, followed by providing some recommendations to enable institutions to employ new technology, overcome existing obstacles, and address challenges in order to implement nexus-based management approaches.

The Equity Imperative in Tertiary Education: Promoting Fairness and Efficiency

ERIC Educational Resources Information Center

Salmi, Jamil; Bassett, Roberta Malee

2014-01-01

While the share of the tertiary education age cohort (19-25) which is being given the opportunity to study has increased worldwide over the past two decades, this does not in fact translate into reduced inequality. For many young people, especially in the developing world, major obstacles such as disparities in terms of gender, minority population…

The Short Circuit Hypothesis of ESL Reading--Or when Language Competence Interferes with Reading Performance.

ERIC Educational Resources Information Center

Clarke, Mark A.

1980-01-01

Examines a sampling of current ESL reading instruction practices, addressing the concern that the lack of a generally accepted theory of L2 reading constitutes a major obstacle to teaching and testing ESL reading skills. Summarizes the results of two studies and discusses their implications for ESL teachers. (MES)

Boosting the Life Chances of Young Men of Color: Evidence from Promising Programs

ERIC Educational Resources Information Center

Wimer, Christopher; Bloom, Dan

2014-01-01

Despite progress on many fronts, young men of color still face many obstacles to success in American society and suffer disproportionately from economic and social disadvantage. In recent years, foundations and state and local governments have launched major initiatives to address this pressing issue. For example, in 2011, the City of New York…

Help-Seeking Stigma in Asian American College Women: The Role of Disordered Eating Cognitions and Psychological Inflexibility

ERIC Educational Resources Information Center

Masuda, Akihiko; Goodnight, Bradly L.; Ng, Stacey Y.; Ward Schaefer, L.; Tully, Erin C.; Chan, Wing Yi; Drake, Chad E.

2017-01-01

Help-seeking stigma is considered a major obstacle to seeking professional psychological services in Asian American college women. Informed in part by objectification theory and the psychological flexibility model of behavior change, the present cross-sectional study examines the role of disordered eating cognition and psychological inflexibility…

Technical Assessment: Integrated Photonics

DTIC Science & Technology

2015-10-01

in global internet protocol traffic as a function of time by local access technology. Photonics continues to play a critical role in enabling this...communication networks. This has enabled services like the internet , high performance computing, and power-efficient large-scale data centers. The...signal processing, quantum information science, and optics for free space applications. However major obstacles challenge the implementation of

Basic Mathematics Test Predicts Statistics Achievement and Overall First Year Academic Success

ERIC Educational Resources Information Center

Fonteyne, Lot; De Fruyt, Filip; Dewulf, Nele; Duyck, Wouter; Erauw, Kris; Goeminne, Katy; Lammertyn, Jan; Marchant, Thierry; Moerkerke, Beatrijs; Oosterlinck, Tom; Rosseel, Yves

2015-01-01

In the psychology and educational science programs at Ghent University, only 36.1% of the new incoming students in 2011 and 2012 passed all exams. Despite availability of information, many students underestimate the scientific character of social science programs. Statistics courses are a major obstacle in this matter. Not all enrolling students…

Planning for Library Automation in the United States.

ERIC Educational Resources Information Center

Culbertson, Don S.

The 15-year history of the development of library automation is traced, and four major obstacles which had to be overcome are identified: the lack of funds for development, programing, and testing; the need for a common data base; the need for cooperative arrangements among institutions; and the need for widely-available on-line processing. Seven…

A Cyber Ray Hope for Ethiopian Children

ERIC Educational Resources Information Center

Szente, Judit; Hoot, James

2004-01-01

Major obstacles threaten the future of Ethiopia. Global publicity regarding the drought of 1986 has left the world with images of starving and orphaned Ethiopian children. Such conditions do still exist in parts of this nation, in which 45 percent of the population falls below the national poverty line (The World Factbook, 2003). In a nation of…

Assessing Sensitivity to Unmeasured Confounding Using a Simulated Potential Confounder

ERIC Educational Resources Information Center

Carnegie, Nicole Bohme; Harada, Masataka; Hill, Jennifer L.

2016-01-01

A major obstacle to developing evidenced-based policy is the difficulty of implementing randomized experiments to answer all causal questions of interest. When using a nonexperimental study, it is critical to assess how much the results could be affected by unmeasured confounding. We present a set of graphical and numeric tools to explore the…

Classroom Debates: Using Speed Rounds to Encourage Greater Participation

ERIC Educational Resources Information Center

Treme, Julianne

2018-01-01

The primary obstacle that can derail the effectiveness of a debate is one in which few students are involved and all of the energy and learning is limited to a few students. This leaves the majority of students passively absorbing information and does not encourage participation among those students that typically do not talk in class. This quick…

Combining Qualitative and Quantitative Methods in the Measurement of Rural Poverty: The Case of Iran

ERIC Educational Resources Information Center

Hayati, Dariush; Karami, Ezatollah; Slee, Bill

2006-01-01

Poverty reduction is one of the major challenges confronting mankind and a principal obstacle to well-being for a large proportion of the world's population. New paradigms of development as advocated by Chambers and others focus strongly on poverty reduction. Poverty is increasingly recognised as a multifaceted concept that can be elucidated…

Learning to Identify the Foreign in Developed Countries: The Example of Ireland

ERIC Educational Resources Information Center

Ireland, Colin

2010-01-01

Among the responsibilities of international educators is to help students begin the process of identifying the foreign in their new environments in order to learn from it. The major obstacle for Americans studying abroad in developed economies, especially in English-speaking countries, is to become sensitive to the subtleties of foreignness. The…

An avian, oncogenic retrovirus replicates in vivo in more than 50% of CD4+ and CD8+ T lymphocytes from an endangered grouse

USDA-ARS?s Scientific Manuscript database

Reoccurring infection of reticuloendotheliosis virus (REV), an avian oncogenic retrovirus, has been a major obstacle in attempts to breed and release an endangered grouse, the Attwater's prairie chicken (Tympanicus cupido attwateri). REV infection of these birds in breeding facilities was found to r...

Students' Emotions as an Organizing Principle in the Social Work Curriculum

ERIC Educational Resources Information Center

Chung, Irene W.

2010-01-01

Students' frustration with the lack of measurable progress in their practice has always been a major obstacle for them in learning to use themselves differentially and to effect changes in their clients (Saari, 1986). This article discusses the author's approach to tending to students' emotions as a central component in organizing and teaching in…

Ethnicity, Education and Empowerment: Identity Construction among Minority Students in Southwestern China

ERIC Educational Resources Information Center

Lee, MaryJo Benton

1998-01-01

Eight percent of the population of the People's Republic of China is comprised of ethnic minority people, people with cultures (particularly languages and religions) that are distinct from the majority (or Han) Chinese. Ethnic students in China and elsewhere face considerable obstacles to getting a good education. A tiny percentage of Chinese…

The Struggle To Be Strong: True Stories by Teens about Overcoming Tough Times.

ERIC Educational Resources Information Center

Desetta, Al, Ed.; Wolin, Sybil, Ed.

This book presents 30 first-person accounts by teenagers that tell how they overcame major life obstacles. Many aren't the everyday problems most kids encounter, which makes their stories especially compelling-and their successes especially inspiring. The young writers wrote their stories to help teenagers with similar problems and stresses. The…

Mentors as Fellow Travelers

ERIC Educational Resources Information Center

Ambrosino, Roberta

2009-01-01

A junior faculty member arrives at an unfamiliar university for a new teaching assignment. She is poised for the adventure, but feels like a traveler at the edge of long, unknown road. She does not know what obstacles or vistas may appear on the road, and wants to avoid major potholes. She takes a nervous look around and finds an experienced…

Transformational Learning: An Investigation of the Emotional Maturation Advancement in Learners Aged 50 and Older

ERIC Educational Resources Information Center

Lundry, Susan L.

2015-01-01

Human beings have spent much time and effort in trying to understand themselves, others, and their world. Mankind uses intellect when trying to understand life but the majority of people continue to encounter frustration, confusion, and a variety of obstacles when dealing with daily challenges and people. Theorists and researchers understand that…

Prophage insertions in mlrA are not the major obstacle to biofilm formation in Escherichia coli O157:H7

USDA-ARS?s Scientific Manuscript database

Background: Although a curli and biofilm expressing phenotype can be induced in Escherichia coli serotype O157:H7, strains examined under laboratory conditions are almost exclusively biofilm deficient and the reason for these deficiencies have remained elusive. CsgD, the central biofilm regulator, i...

An Interactive Computer Model for Improved Student Understanding of Random Particle Motion and Osmosis

ERIC Educational Resources Information Center

Kottonau, Johannes

2011-01-01

Effectively teaching the concepts of osmosis to college-level students is a major obstacle in biological education. Therefore, a novel computer model is presented that allows students to observe the random nature of particle motion simultaneously with the seemingly directed net flow of water across a semipermeable membrane during osmotic…

Social Equality as Groundwork for Sustainable Schooling: The Free Lunch Issue

ERIC Educational Resources Information Center

Kairiene, Brigita; Sprindziunas, Andrius

2016-01-01

The purpose of the present study was to discuss the way of organizing free lunch at public schools as an important precondition for social equality and sustainability in school, by revealing acute forms of social disjunction in Lithuanian schools as a major incongruity with Children Rights, and an obstacle to the achievement of general education…

Pronunciation for the Arab Learners of EFL: Planning for Better Outcomes

ERIC Educational Resources Information Center

Hassan Al-Ahdal, Arif Ahmed Mohammed; Al-Hattami, Abdulghani Ali; Al-Awaid, Salmeen Abdulrahman Abdullah; Al-Mashaqba, Nisreen Juma'a Hamed

2015-01-01

Arabic and English belong to two different linguistic families: resultantly, some Arabic speaking learners of English in both SL and FL situations have a major obstacle to overcome to be intelligible to other users, especially in the international context. Of the various skills one needs to acquire to become "proficient" in a language…

Quick genome sequencing of “Candidatus Liberibacter” strains by use of Enrichment-Enlargement-Next generation sequencing (EEN)

USDA-ARS?s Scientific Manuscript database

Members of “Candidatus Liberibacter” are associated with several important plant diseases such as citrus Huanglongbing (HLB) and potato zebra chip (ZC) disease. Inability to culture and low titers in infected hosts have been major obstacles for research on these bacteria. The use of whole genome seq...

Math Avoidance: A Barrier to American Indian Science Education and Science Careers.

ERIC Educational Resources Information Center

Green, Rayna

1978-01-01

For American Indian students, math anxiety and math avoidance are the most serious obstacles to general education and to the choice of scientific careers. Indian students interviewed generally exhibited fear and loathing of mathematics and a major lack of basic skills which were caused by a missing or negative impression of the mathematics…

Building a Nation That Works: Designing TANF for the Workplace.

ERIC Educational Resources Information Center

Jobs for the Future, Boston, MA.

Temporary Assistance to Needy Families (TANF) needs to focus more directly on what happens in the workplace and consider the needs of employers. Employers identify skill levels of both job applicants and employees as a major obstacle to employing and retaining TANF recipients and other entry-level workers as well as the cost of entry-level…

Difficulties of Academic Achievement in Principles of Accounting Courses from the Student Perspective: Evidence from Libya

ERIC Educational Resources Information Center

Tailab, Mohamed M.

2013-01-01

Many studies by researchers and accounting educators explore various factors associated with the success or failure of accounting majors in college level accounting courses. This paper identifies and summarizes the main obstacles associated with low student academic achievement in introductory courses in the College of Accounting at Al-Jabal…

A weeding in ten-year-old northern hardwoods - methods and time requirements

Treesearch

Barton M. Blum; Stanley M. Filip

1962-01-01

Although weeding young northern hardwoods is not a common practice, most foresters will agree that weeding such stands is silviculturally sound in terms of improved growth and quality. Major obstacle to the widespread weeding of young stands as a routine cultural treatment is lack of information about the techniques and costs involved.

Principals' Approaches to Cultivating Teacher Effectiveness: Constraints and Opportunities in Hiring, Assigning, Evaluating, and Developing Teachers

ERIC Educational Resources Information Center

Donaldson, Morgaen L.

2013-01-01

Purpose: How principals hire, assign, evaluate, and provide growth opportunities to teachers likely have major ramifications for teacher effectiveness and student learning. This article reports on the barriers principals encountered when carrying out these functions and variations in the degree to which they identified obstacles and problem-solved…

Robust obstacle detection for unmanned surface vehicles

NASA Astrophysics Data System (ADS)

Qin, Yueming; Zhang, Xiuzhi

2018-03-01

Obstacle detection is of essential importance for Unmanned Surface Vehicles (USV). Although some obstacles (e.g., ships, islands) can be detected by Radar, there are many other obstacles (e.g., floating pieces of woods, swimmers) which are difficult to be detected via Radar because these obstacles have low radar cross section. Therefore, detecting obstacle from images taken onboard is an effective supplement. In this paper, a robust vision-based obstacle detection method for USVs is developed. The proposed method employs the monocular image sequence captured by the camera on the USVs and detects obstacles on the sea surface from the image sequence. The experiment results show that the proposed scheme is efficient to fulfill the obstacle detection task.

Analysis and design of a capsule landing system and surface vehicle control system for Mars exploration

NASA Technical Reports Server (NTRS)

Frederick, D. K.; Lashmet, P. K.; Sandor, G. N.; Shen, C. N.; Smith, E. V.; Yerazunis, S. W.

1973-01-01

Problems related to the design and control of a mobile planetary vehicle to implement a systematic plan for the exploration of Mars are reported. Problem areas include: vehicle configuration, control, dynamics, systems and propulsion; systems analysis, terrain modeling and path selection; and chemical analysis of specimens. These tasks are summarized: vehicle model design, mathematical model of vehicle dynamics, experimental vehicle dynamics, obstacle negotiation, electrochemical controls, remote control, collapsibility and deployment, construction of a wheel tester, wheel analysis, payload design, system design optimization, effect of design assumptions, accessory optimal design, on-board computer subsystem, laser range measurement, discrete obstacle detection, obstacle detection systems, terrain modeling, path selection system simulation and evaluation, gas chromatograph/mass spectrometer system concepts, and chromatograph model evaluation and improvement.

Advanced obstacle avoidance for a laser based wheelchair using optimised Bayesian neural networks.

PubMed

Trieu, Hoang T; Nguyen, Hung T; Willey, Keith

2008-01-01

In this paper we present an advanced method of obstacle avoidance for a laser based intelligent wheelchair using optimized Bayesian neural networks. Three neural networks are designed for three separate sub-tasks: passing through a door way, corridor and wall following and general obstacle avoidance. The accurate usable accessible space is determined by including the actual wheelchair dimensions in a real-time map used as inputs to each networks. Data acquisitions are performed separately to collect the patterns required for specified sub-tasks. Bayesian frame work is used to determine the optimal neural network structure in each case. Then these networks are trained under the supervision of Bayesian rule. Experiment results showed that compare to the VFH algorithm our neural networks navigated a smoother path following a near optimum trajectory.

International growth of neuropsychology.

PubMed

Ponsford, Jennie

2017-11-01

Twenty-five years ago, the field of neuropsychology was well established in North America, Europe, and Australia, with less presence elsewhere. This article discusses the development of neuropsychology over the last 25 years in other regions. The growth of neuropsychology in Asia, Africa, the Middle East, Central and South America, and New Zealand is reviewed. Sources drawn on include a 2016 edition of The Clinical Neuropsychologist describing the practice of neuropsychology in 18 countries; papers on the profession of neuropsychology in Latin America (Arango-Lasprilla, Stevens, Paredes, Ardila, & Rivera, 2016), the history of neuropsychology in Asia (Lee, Wang, & Collinson, 2016), and neuropsychology in Central America (Judd, 2017); INSNET; and personal communications. There has been tremendous variability in the development of neuropsychology across these regions over the last 25 years. Obstacles to the growth of neuropsychology have included economic constraints on health care provision, limited availability of appropriate assessment and treatment methods, linguistic diversity and illiteracy, stigma toward and/or lack of awareness of neuropsychological disorders, lack of graduate training and clinical supervision, absence of accreditation of neuropsychologists as a clinical profession, poor pay, and diminished visibility of the field within the regional culture. Despite these obstacles, neuropsychological research and practice is establishing itself in these regions and has grown significantly over the last quarter century. Major challenges remain in establishing awareness of the significance of and developing culturally appropriate methods of assessing and rehabilitating cognitive aspects of brain disorders, training programs, recognition as a profession, and dedicated funding for neuropsychology positions. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Distributed health data networks: a practical and preferred approach to multi-institutional evaluations of comparative effectiveness, safety, and quality of care.

PubMed

Brown, Jeffrey S; Holmes, John H; Shah, Kiran; Hall, Ken; Lazarus, Ross; Platt, Richard

2010-06-01

Comparative effectiveness research, medical product safety evaluation, and quality measurement will require the ability to use electronic health data held by multiple organizations. There is no consensus about whether to create regional or national combined (eg, "all payer") databases for these purposes, or distributed data networks that leave most Protected Health Information and proprietary data in the possession of the original data holders. Demonstrate functions of a distributed research network that supports research needs and also address data holders concerns about participation. Key design functions included strong local control of data uses and a centralized web-based querying interface. We implemented a pilot distributed research network and evaluated the design considerations, utility for research, and the acceptability to data holders of methods for menu-driven querying. We developed and tested a central, web-based interface with supporting network software. Specific functions assessed include query formation and distribution, query execution and review, and aggregation of results. This pilot successfully evaluated temporal trends in medication use and diagnoses at 5 separate sites, demonstrating some of the possibilities of using a distributed research network. The pilot demonstrated the potential utility of the design, which addressed the major concerns of both users and data holders. No serious obstacles were identified that would prevent development of a fully functional, scalable network. Distributed networks are capable of addressing nearly all anticipated uses of routinely collected electronic healthcare data. Distributed networks would obviate the need for centralized databases, thus avoiding numerous obstacles.

Fast obstacle detection based on multi-sensor information fusion

NASA Astrophysics Data System (ADS)

Lu, Linli; Ying, Jie

2014-11-01

Obstacle detection is one of the key problems in areas such as driving assistance and mobile robot navigation, which cannot meet the actual demand by using a single sensor. A method is proposed to realize the real-time access to the information of the obstacle in front of the robot and calculating the real size of the obstacle area according to the mechanism of the triangle similarity in process of imaging by fusing datum from a camera and an ultrasonic sensor, which supports the local path planning decision. In the part of image analyzing, the obstacle detection region is limited according to complementary principle. We chose ultrasonic detection range as the region for obstacle detection when the obstacle is relatively near the robot, and the travelling road area in front of the robot is the region for a relatively-long-distance detection. The obstacle detection algorithm is adapted from a powerful background subtraction algorithm ViBe: Visual Background Extractor. We extracted an obstacle free region in front of the robot in the initial frame, this region provided a reference sample set of gray scale value for obstacle detection. Experiments of detecting different obstacles at different distances respectively, give the accuracy of the obstacle detection and the error percentage between the calculated size and the actual size of the detected obstacle. Experimental results show that the detection scheme can effectively detect obstacles in front of the robot and provide size of the obstacle with relatively high dimensional accuracy.

Introduction of frictional and turning function for pedestrian outflow with an obstacle.

PubMed

Yanagisawa, Daichi; Kimura, Ayako; Tomoeda, Akiyasu; Nishi, Ryosuke; Suma, Yushi; Ohtsuka, Kazumichi; Nishinari, Katsuhiro

2009-09-01

In this paper, two important factors which affect the pedestrian outflow at a bottleneck significantly are studied in detail to analyze the effect of an obstacle setup in front of an exit. One is a conflict at an exit when pedestrians evacuate from a room. We use floor field model for simulating such behavior, which is a well-studied pedestrian model using cellular automata. The conflicts have been taken into account by the friction parameter. However, the friction parameter so far is a constant and does not depend on the number of the pedestrians conflicting at the same time. Thus, we have improved the friction parameter by the frictional function, which is a function of the number of the pedestrians involved in the conflict. Second, we have presented the cost of turning of pedestrians at the exit. Since pedestrians have inertia, their walking speeds decrease when they turn and the pedestrian outflow decreases. The validity of the extended model, which includes the frictional function and the turning function, is supported by the comparison of a mean-field theory and real experiments. We have observed that the pedestrian flow increases when we put an obstacle in front of an exit in our real experiments. The analytical results clearly explains the mechanism of the effect of the obstacle, i.e., the obstacle blocks pedestrians moving to the exit and decreases the average number of pedestrians involved in the conflict. We have also found that an obstacle works more effectively when we shift it from the center since pedestrians go through the exit with less turning.

DeepAnomaly: Combining Background Subtraction and Deep Learning for Detecting Obstacles and Anomalies in an Agricultural Field.

PubMed

Christiansen, Peter; Nielsen, Lars N; Steen, Kim A; Jørgensen, Rasmus N; Karstoft, Henrik

2016-11-11

Convolutional neural network (CNN)-based systems are increasingly used in autonomous vehicles for detecting obstacles. CNN-based object detection and per-pixel classification (semantic segmentation) algorithms are trained for detecting and classifying a predefined set of object types. These algorithms have difficulties in detecting distant and heavily occluded objects and are, by definition, not capable of detecting unknown object types or unusual scenarios. The visual characteristics of an agriculture field is homogeneous, and obstacles, like people, animals and other obstacles, occur rarely and are of distinct appearance compared to the field. This paper introduces DeepAnomaly, an algorithm combining deep learning and anomaly detection to exploit the homogenous characteristics of a field to perform anomaly detection. We demonstrate DeepAnomaly as a fast state-of-the-art detector for obstacles that are distant, heavily occluded and unknown. DeepAnomaly is compared to state-of-the-art obstacle detectors including "Faster R-CNN: Towards Real-Time Object Detection with Region Proposal Networks" (RCNN). In a human detector test case, we demonstrate that DeepAnomaly detects humans at longer ranges (45-90 m) than RCNN. RCNN has a similar performance at a short range (0-30 m). However, DeepAnomaly has much fewer model parameters and (182 ms/25 ms =) a 7.28-times faster processing time per image. Unlike most CNN-based methods, the high accuracy, the low computation time and the low memory footprint make it suitable for a real-time system running on a embedded GPU (Graphics Processing Unit).

DeepAnomaly: Combining Background Subtraction and Deep Learning for Detecting Obstacles and Anomalies in an Agricultural Field

PubMed Central

Christiansen, Peter; Nielsen, Lars N.; Steen, Kim A.; Jørgensen, Rasmus N.; Karstoft, Henrik

2016-01-01

Convolutional neural network (CNN)-based systems are increasingly used in autonomous vehicles for detecting obstacles. CNN-based object detection and per-pixel classification (semantic segmentation) algorithms are trained for detecting and classifying a predefined set of object types. These algorithms have difficulties in detecting distant and heavily occluded objects and are, by definition, not capable of detecting unknown object types or unusual scenarios. The visual characteristics of an agriculture field is homogeneous, and obstacles, like people, animals and other obstacles, occur rarely and are of distinct appearance compared to the field. This paper introduces DeepAnomaly, an algorithm combining deep learning and anomaly detection to exploit the homogenous characteristics of a field to perform anomaly detection. We demonstrate DeepAnomaly as a fast state-of-the-art detector for obstacles that are distant, heavily occluded and unknown. DeepAnomaly is compared to state-of-the-art obstacle detectors including “Faster R-CNN: Towards Real-Time Object Detection with Region Proposal Networks” (RCNN). In a human detector test case, we demonstrate that DeepAnomaly detects humans at longer ranges (45–90 m) than RCNN. RCNN has a similar performance at a short range (0–30 m). However, DeepAnomaly has much fewer model parameters and (182 ms/25 ms =) a 7.28-times faster processing time per image. Unlike most CNN-based methods, the high accuracy, the low computation time and the low memory footprint make it suitable for a real-time system running on a embedded GPU (Graphics Processing Unit). PMID:27845717

Any way you look at it, successful obstacle negotiation needs visually guided on-line foot placement regulation during the approach phase.

PubMed

Patla, Aftab E; Greig, Michael

In the two experiments discussed in this paper we quantified obstacle avoidance performance characteristics carried out open loop (without vision) but with different initial visual sampling conditions and compared it to the full vision condition. The initial visual sampling conditions included: static vision (SV), vision during forward walking for three steps and stopping (FW), vision during forward walking for three steps and not stopping (FW-NS), and vision during backward walking for three steps and stopping (BW). In experiment 1, we compared performance during SV, FW and BW with full vision condition, while in the second experiment we compared performance during FW and FW-NS conditions. The questions we wanted to address are: Is ecologically valid dynamic visual sampling of the environment superior to static visual sampling for open loop obstacle avoidance task? What are the reasons for failure in performing open loop obstacle avoidance task? The results showed that irrespective of the initial visual sampling condition when open loop control is initiated from a standing posture, the success rate was only approximately 50%. The main reason for the high failure rates was not inappropriate limb elevation, but incorrect foot placement before the obstacle. The second experiment showed that it is not the nature of visual sampling per se that influences success rate, but the fact that the open loop obstacle avoidance task is initiated from a standing posture. The results of these two experiments clearly demonstrate the importance of on-line visual information for adaptive human locomotion.

Obstacle avoidance in social groups: new insights from asynchronous models

PubMed Central

Croft, Simon; Budgey, Richard; Pitchford, Jonathan W.; Wood, A. Jamie

2015-01-01

For moving animals, the successful avoidance of hazardous obstacles is an important capability. Despite this, few models of collective motion have addressed the relationship between behavioural and social features and obstacle avoidance. We develop an asynchronous individual-based model for social movement which allows social structure within groups to be included. We assess the dynamics of group navigation and resulting collision risk in the context of information transfer through the system. In agreement with previous work, we find that group size has a nonlinear effect on collision risk. We implement examples of possible network structures to explore the impact social preferences have on collision risk. We show that any social heterogeneity induces greater obstacle avoidance with further improvements corresponding to groups containing fewer influential individuals. The model provides a platform for both further theoretical investigation and practical application. In particular, we argue that the role of social structures within bird flocks may have an important role to play in assessing the risk of collisions with wind turbines, but that new methods of data analysis are needed to identify these social structures. PMID:25833245

Evacuation simulation with consideration of obstacle removal and using game theory

NASA Astrophysics Data System (ADS)

Lin, Guan-Wen; Wong, Sai-Keung

2018-06-01

In this paper, we integrate a cellular automaton model with game theory to simulate crowd evacuation from a room with consideration of obstacle removal. The room has one or more exits, one of which is blocked by obstacles. The obstacles at the exit can be removed by volunteers. We investigate the cooperative and defective behaviors of pedestrians during evacuation. The yielder game and volunteer's dilemma game are employed to resolve interpedestrian conflict. An anticipation floor field is proposed to guide the pedestrians to avoid obstacles that are being removed. We conducted experiments to determine how a variety of conditions affect overall crowd evacuation and volunteer evacuation times. The conditions were the start time of obstacle removal, number of obstacles, placement of obstacles, time spent in obstacle removal, strength of the anticipation floor field, and obstacle visibility distance. We demonstrate how reciprocity can be achieved among pedestrians and increases the efficiency of the entire evacuation process.

Implications of the Naturalistic Decision Making Framework for Information Dominance.

DTIC Science & Technology

1997-07-01

Information Dominance , defined as an operational advantage obtained through superior effectiveness of informational activity. NDM is the study of how people use their experience to make decisions in field settings. Expertise was considered at both the individual and the team level of decision making. The report defines the components of expertise and identifies obstacles to the acquisition of Information Dominance . These obstacles include: (1) excessive data, (2) pre-processed data, (3) excessive procedures, (4) performing formal analyses, (5) passive

Dynamic interaction of two-phase debris flow with pyramidal defense structures: An optimal strategy to efficiently protecting the desired area

NASA Astrophysics Data System (ADS)

Kattel, Parameshwari; Kafle, Jeevan; Fischer, Jan-Thomas; Mergili, Martin; Tuladhar, Bhadra Man; Pudasaini, Shiva P.

2017-04-01

In this work we analyze the dynamic interaction of two phase debris flows with pyramidal obstacles. To simulate the dynamic interaction of two-phase debris flow (a mixture of solid particles and viscous fluid) with obstacles of different dimensions and orientations, we employ the general two-phase mass flow model (Pudasaini, 2012). The model consists of highly non-linear partial differential equations representing the mass and momentum conservations for both solid and fluid. Besides buoyancy, the model includes some dominant physical aspects of the debris flows such as generalized drag, virtual mass and non-Newtonian viscous stress as induced by the gradient of solid-volume-fraction. Simulations are performed with high-resolution numerical schemes to capture essential dynamics, including the strongly re-directed flow with multiple stream lines, mass arrest and debris-vacuum generation when the rapidly cascading debris mass suddenly encounters the obstacle. The solid and fluid phases show fundamentally different interactions with obstacles, flow spreading and dispersions, run-out dynamics, and deposition morphology. A forward-facing pyramid deflects the mass wider, and a rearward-facing pyramid arrests a portion of solid-mass at its front. Our basic study reveals that appropriately installed obstacles, their dimensions and orientations have a significant influence on the flow dynamics, material redistribution and redirection. The precise knowledge of the change in dynamics is of great importance for the optimal and effective protection of designated areas along the mountain slopes and the runout zones. Further important results are, that specific installations lead to redirect either solid, or fluid, or both, in the desired amounts and directions. The present method of the complex interactions of real two-phase mass flows with the obstacles may help us to construct defense structures and to design advanced and physics-based engineering solutions for the prevention and mitigation of natural hazards caused by geophysical mass flows. References: Pudasaini, S. P. (2012): A general two-phase debris flow model. J. Geophys. Res. 117, F03010, doi: 10.1029/ 2011JF002186.

The addition of stripes (a version of the 'horizontal-vertical illusion') increases foot clearance when crossing low-height obstacles.

PubMed

Foster, Richard J; Buckley, John G; Whitaker, David; Elliott, David B

2016-07-01

Trips over obstacles are one of the main causes of falling in older adults, with vision playing an important role in successful obstacle negotiation. We determined whether a horizontal-vertical illusion, superimposed onto low-height obstacles to create a perceived increase in obstacle height, increased foot clearances during obstacle negotiation thus reducing the likelihood of tripping. Eleven adults (mean ± 1 SD: age 27.3 ± 5.1 years) negotiated obstacles of varying heights (3, 5, 7 cm) with four different appearance conditions; two were obstacles with a horizontal-vertical illusion (vertical stripes of different thickness) superimposed on the front, one was a plain obstacle and the fourth a plain obstacle with a horizontal black line painted on the top edge. Foot clearance parameters were compared across conditions. Both illusions led to a significant increase in foot clearance when crossing the obstacle, compared to the plain condition, irrespective of obstacle height. Superimposing a horizontal-vertical illusion onto low-height obstacles can increase foot clearance, and its use on the floor section of a double-glazing door frame for example may reduce the incidence of tripping in the home. Practitioner Summary: Low-height obstacles such as the floor section of a double-glazing door frame are potential tripping hazards. In a gait lab-based study we found that a horizontal-vertical illusion superimposed onto low-height obstacles led to significantly higher foot clearances; indicating their potential as a useful safety measure.

Strategies for handling ethical problems in end of life care: obstacles and possibilities.

PubMed

Rejnö, Åsa; Berg, Linda

2015-11-01

In end of life care, ethical problems often come to the fore. Little research is performed on ways or strategies for handling those problems and even less on obstacles to and possibilities of using such strategies. A previous study illuminated stroke team members' experiences of ethical problems and how the teams managed the situation when caring for patients faced with sudden and unexpected death from stroke. These findings have been further explored in this study. The aim of the study was to illuminate obstacles and possibilities perceived by stroke team members in using strategies for handling ethical problems when caring for patients afflicted by sudden and unexpected death caused by stroke. A qualitative method with combined deductive and inductive content analysis was utilized. Data were collected through individual interviews with 15 stroke team members working in stroke units of two associated county hospitals in western Sweden. The study was approved by the Regional Ethics Review Board, Gothenburg, Sweden. Permission was also obtained from the director of each stroke unit. All the studied strategies for handling of ethical problems were found to have both obstacles and possibilities. Uncertainty is shown as a major obstacle and unanimity as a possibility in the use of the strategies. The findings also illuminate the value of the concept "the patient's best interests" as a starting point for the carers' ethical reasoning. The concept "the patient's best interests" used as a starting point for ethical reasoning among the carers is not explicitly defined yet, which might make this value difficult to use both as a universal concept and as an argument for decisions. Carers therefore need to strengthen their argumentation and reflect on and use ethically grounded arguments and defined ethical values like dignity in their clinical work and decisions. © The Author(s) 2014.

Cleaning of first mirrors in ITER by means of radio frequency discharges.

PubMed

Leipold, F; Reichle, R; Vorpahl, C; Mukhin, E E; Dmitriev, A M; Razdobarin, A G; Samsonov, D S; Marot, L; Moser, L; Steiner, R; Meyer, E

2016-11-01

First mirrors of optical diagnostics in ITER are subject to charge exchange fluxes of Be, W, and potentially other elements. This may degrade the optical performance significantly via erosion or deposition. In order to restore reflectivity, cleaning by applying radio frequency (RF) power to the mirror itself and thus creating a discharge in front of the mirror will be used. The plasma generated in front of the mirror surface sputters off deposition, restoring its reflectivity. Although the functionality of such a mirror cleaning technique is proven in laboratory experiments, the technical implementation in ITER revealed obstacles which needs to be overcome: Since the discharge as an RF load in general is not very well matched to the power generator and transmission line, power reflections will occur leading to a thermal load of the cable. Its implementation for ITER requires additional R&D. This includes the design of mirrors as RF electrodes, as well as feeders and matching networks inside the vacuum vessel. Mitigation solutions will be evaluated and discussed. Furthermore, technical obstacles (i.e., cooling water pipes for the mirrors) need to be solved. Since cooling water lines are usually on ground potential at the feed through of the vacuum vessel, a solution to decouple the ground potential from the mirror would be a major simplification. Such a solution will be presented.

Latin American guidelines on hypertension. Latin American Expert Group.

PubMed

Sanchez, Ramiro A; Ayala, Miryam; Baglivo, Hugo; Velazquez, Carlos; Burlando, Guillermo; Kohlmann, Oswaldo; Jimenez, Jorge; Jaramillo, Patricio López; Brandao, Ayrton; Valdes, Gloria; Alcocer, Luis; Bendersky, Mario; Ramirez, Agustín José; Zanchetti, Alberto

2009-05-01

Hypertension is a highly prevalent cardiovascular risk factor in the world and particularly overwhelming in low and middle-income countries. Recent reports from the WHO and the World Bank highlight the importance of chronic diseases such as hypertension as an obstacle to the achievement of good health status. It must be added that for most low and middle-income countries, deficient strategies of primary healthcare are the major obstacles for blood pressure control. Furthermore, the epidemiology of hypertension and related diseases, healthcare resources and priorities, the socioeconomic status of the population vary considerably in different countries and in different regions of individual countries. Considering the low rates of blood pressure control achieved in Latin America and the benefits that can be expected from an improved control, it was decided to invite specialists from different Latin American countries to analyze the regional situation and to provide a consensus document on detection, evaluation and treatment of hypertension that may prove to be cost-utility adequate. The recommendations here included are the result of preparatory documents by invited experts and a subsequent very active debate by different discussion panels, held during a 2-day sessions in Asuncion, Paraguay, in May 2008. Finally, in order to improve clinical practice, the publication of the guidelines should be followed by implementation of effective interventions capable of overcoming barriers (cognitive, behavioral and affective) preventing attitude changes in both physicians and patients.

Conceptual obstacles to making use of four smoking-cessation strategies: What reasons do light smokers give for rejecting strategies?

PubMed Central

Ryan, Michael P; Hinojosa, Jennifer J

2015-01-01

Some smokers have safety and cost concerns about nicotine replacement therapy which discourage its use. We recruited 56 young adult light smokers to read detailed descriptions of a hybrid nicotine replacement therapy, a prescription drug treatment, scheduled reduced smoking, and a menu of self-help tactics. Participants listed five reasons smokers might reject each strategy. An emergent-category content analysis classified each response with a high degree of inter-rater reliability. Only one-third of 32 concerns were strategy-specific; the majority focused on the general difficulty of quitting. Most prevalent were “continued cravings,” “addiction too strong,” “takes too long,” and “won’t work.” These and other concerns reflect conceptual obstacles to be surmounted in smoking-cessation interventions. PMID:28070381

Challenges and issues of geolocation in clinical environment.

PubMed

Issom, David-Zacharie; Hagry, Claire; Wodia Mendo, Laetitia; Seng, Henry; Ehrler, Frederic; Lovis, Christian

2012-01-01

Reaching a good indoor geolocation without deploying extensive and expensive infrastructure is a challenge, because satellite positioning system is not available indoors. Geolocation could be of major use in healthcare facilities; to help care providers, visitors and patients to navigate, to improve movements and flows efficiency or to implement location-awareness systems. A system able to provide the location of a person in a hospital requires precision, multi-floors and obstacles management and should also perform in basements and outdoors. Such system needs also to be insensitive to environmental variations occurring in a hospital. These changes may be various kinds of obstacles. These can be the displacement of metallic objects, metallic machines, strong magnetic fields or simply human displacement. A system conforming to the above requirements can also answer various security questions, operational workflow management but also assist movement of people.

DeepGene: an advanced cancer type classifier based on deep learning and somatic point mutations.

PubMed

Yuan, Yuchen; Shi, Yi; Li, Changyang; Kim, Jinman; Cai, Weidong; Han, Zeguang; Feng, David Dagan

2016-12-23

With the developments of DNA sequencing technology, large amounts of sequencing data have become available in recent years and provide unprecedented opportunities for advanced association studies between somatic point mutations and cancer types/subtypes, which may contribute to more accurate somatic point mutation based cancer classification (SMCC). However in existing SMCC methods, issues like high data sparsity, small volume of sample size, and the application of simple linear classifiers, are major obstacles in improving the classification performance. To address the obstacles in existing SMCC studies, we propose DeepGene, an advanced deep neural network (DNN) based classifier, that consists of three steps: firstly, the clustered gene filtering (CGF) concentrates the gene data by mutation occurrence frequency, filtering out the majority of irrelevant genes; secondly, the indexed sparsity reduction (ISR) converts the gene data into indexes of its non-zero elements, thereby significantly suppressing the impact of data sparsity; finally, the data after CGF and ISR is fed into a DNN classifier, which extracts high-level features for accurate classification. Experimental results on our curated TCGA-DeepGene dataset, which is a reformulated subset of the TCGA dataset containing 12 selected types of cancer, show that CGF, ISR and DNN all contribute in improving the overall classification performance. We further compare DeepGene with three widely adopted classifiers and demonstrate that DeepGene has at least 24% performance improvement in terms of testing accuracy. Based on deep learning and somatic point mutation data, we devise DeepGene, an advanced cancer type classifier, which addresses the obstacles in existing SMCC studies. Experiments indicate that DeepGene outperforms three widely adopted existing classifiers, which is mainly attributed to its deep learning module that is able to extract the high level features between combinatorial somatic point mutations and cancer types.

Medical messages in the media--barriers and solutions to improving medical journalism.

PubMed

Larsson, Anna; Oxman, Andrew D; Carling, Cheryl; Herrin, Jeph

2003-12-01

Medical issues are widely reported in the mass media. These reports influence the general public, policy makers and health-care professionals. This information should be valid, but is often criticized for being speculative, inaccurate and misleading. An understanding of the obstacles medical reporters meet in their work can guide strategies for improving the informative value of medical journalism. To investigate constraints on improving the informative value of medical reports in the mass media and elucidate possible strategies for addressing these. We reviewed the literature and organized focus groups, a survey of medical journalists in 37 countries, and semi-structured telephone interviews. We identified nine barriers to improving the informative value of medical journalism: lack of time, space and knowledge; competition for space and audience; difficulties with terminology; problems finding and using sources; problems with editors and commercialism. Lack of time, space and knowledge were the most common obstacles. The importance of different obstacles varied with the type of media and experience. Many health reporters feel that it is difficult to find independent experts willing to assist journalists, and also think that editors need more education in critical appraisal of medical news. Almost all of the respondents agreed that the informative value of their reporting is important. Nearly everyone wanted access to short, reliable and up-to-date background information on various topics available on the Internet. A majority (79%) was interested in participating in a trial to evaluate strategies to overcome identified constraints. Medical journalists agree that the validity of medical reporting in the mass media is important. A majority acknowledge many constraints. Mutual efforts of health-care professionals and journalists employing a variety of strategies will be needed to address these constraints.

Medical messages in the media – barriers and solutions to improving medical journalism

PubMed Central

Larsson, Anna; Oxman, Andrew D; Carling, Cheryl; Herrin, Jeph

2003-01-01

Abstract Context  Medical issues are widely reported in the mass media. These reports influence the general public, policy makers and health‐care professionals. This information should be valid, but is often criticized for being speculative, inaccurate and misleading. An understanding of the obstacles medical reporters meet in their work can guide strategies for improving the informative value of medical journalism. Objective  To investigate constraints on improving the informative value of medical reports in the mass media and elucidate possible strategies for addressing these. Design  We reviewed the literature and organized focus groups, a survey of medical journalists in 37 countries, and semi‐structured telephone interviews. Results  We identified nine barriers to improving the informative value of medical journalism: lack of time, space and knowledge; competition for space and audience; difficulties with terminology; problems finding and using sources; problems with editors and commercialism. Lack of time, space and knowledge were the most common obstacles. The importance of different obstacles varied with the type of media and experience. Many health reporters feel that it is difficult to find independent experts willing to assist journalists, and also think that editors need more education in critical appraisal of medical news. Almost all of the respondents agreed that the informative value of their reporting is important. Nearly everyone wanted access to short, reliable and up‐to‐date background information on various topics available on the Internet. A majority (79%) was interested in participating in a trial to evaluate strategies to overcome identified constraints. Conclusion  Medical journalists agree that the validity of medical reporting in the mass media is important. A majority acknowledge many constraints. Mutual efforts of health‐care professionals and journalists employing a variety of strategies will be needed to address these constraints. PMID:15040794

Health resources and health strategies among older Swedish-speaking Finns--a hermeneutic study.

PubMed

Kulla, Gunilla; Sarvimäki, Anneli; Fagerström, Lisbeth

2006-03-01

Research has shown that the Swedish-speaking Finns have better health than the Finnish-speaking majority. The aim of this paper was to explore the health resources and health strategies among home-dwelling Swedish-speaking Finns aged 75 or older. The objective was to develop health-promotive nursing care for this group. Data was collected through recorded semistructured conversations with 22 older persons. The conversations were transcribed and interpreted through a hermeneutic approach. The material was read through several times and compiled into 22 narratives with relevant quotations. The narratives were subsequently summarised into one core narrative under each major category, to present the health resources and health strategies. Six categories were found: the Positive, the Social, the Active, the Adaptable, the Stubborn and the Passive. Within the Positive category, morale played an important role as a health resource and health strategy. Within the Social category, social activities were regarded as both health resources and health strategies, whereas their absence was a health obstacle. Within the Active category, a wide range of physical activities played an important role. Within the Adaptable category, contentment was a health resource. Within the Stubborn category, stubbornness itself was a health resource, whereas strong belief was a health strategy. Within the Passive category, although health obstacles permeated the life context, contentment and caution were seen as health resources. The vision of the future varied from the confidence found in the Positive category to the uncertainty prevalent in the Passive category. The main health resources and strategies used by the elderly Swedish-speaking Finns were related to social and other activities as well as to personality. Transforming health obstacles into resources could be an important health-promotive nursing strategy.

Investigation of obstacle effect to improve conjugate heat transfer in backward facing step channel using fast simulation of incompressible flow

NASA Astrophysics Data System (ADS)

Nouri-Borujerdi, Ali; Moazezi, Arash

2018-01-01

The current study investigates the conjugate heat transfer characteristics for laminar flow in backward facing step channel. All of the channel walls are insulated except the lower thick wall under a constant temperature. The upper wall includes a insulated obstacle perpendicular to flow direction. The effect of obstacle height and location on the fluid flow and heat transfer are numerically explored for the Reynolds number in the range of 10 ≤ Re ≤ 300. Incompressible Navier-Stokes and thermal energy equations are solved simultaneously in fluid region by the upwind compact finite difference scheme based on flux-difference splitting in conjunction with artificial compressibility method. In the thick wall, the energy equation is obtained by Laplace equation. A multi-block approach is used to perform parallel computing to reduce the CPU time. Each block is modeled separately by sharing boundary conditions with neighbors. The developed program for modeling was written in FORTRAN language with OpenMP API. The obtained results showed that using of the multi-block parallel computing method is a simple robust scheme with high performance and high-order accurate. Moreover, the obtained results demonstrated that the increment of Reynolds number and obstacle height as well as decrement of horizontal distance between the obstacle and the step improve the heat transfer.

Tumor-associated myeloid cells as guiding forces of cancer cell stemness.

PubMed

Sica, Antonio; Porta, Chiara; Amadori, Alberto; Pastò, Anna

2017-08-01

Due to their ability to differentiate into various cell types and to support tissue regeneration, stem cells simultaneously became the holy grail of regenerative medicine and the evil obstacle in cancer therapy. Several studies have investigated niche-related conditions that favor stemness properties and increasingly emphasized their association with an inflammatory environment. Tumor-associated macrophages (TAMs) and myeloid-derived suppressor cells (MDSCs) are major orchestrators of cancer-related inflammation, able to dynamically express different polarized inflammatory programs that promote tumor outgrowth, including tumor angiogenesis, immunosuppression, tissue remodeling and metastasis formation. In addition, these myeloid populations support cancer cell stemness, favoring tumor maintenance and progression, as well as resistance to anticancer treatments. Here, we discuss inflammatory circuits and molecules expressed by TAMs and MDSCs as guiding forces of cancer cell stemness.

Role of inducible nitric oxide synthase in transplant arteriosclerosis.

PubMed

Lee, P C; Shears, L L; Billiar, T R

1999-12-01

1. Transplant arteriosclerosis is a major obstacle to long-term allograft survival. Nitric oxide (NO) has been implicated as a mediator in the development of this disease. 2. We and others have shown that inducible nitric oxide synthase (iNOS) is up-regulated in allografts with transplant arteriosclerosis. Despite the acute cytotoxic effects produced by high levels of NO, a chronic increase in NO availability is protective against neointimal hyperplasia, mainly by suppressing the inflammatory cell recruitment and neointimal smooth muscle cell accumulation. 3. Currently, we have the technology to directly transfer the iNOS gene to allografts. We have demonstrated that this exciting strategy is feasible and therapeutic and may improve the long-term survival and function of allografts. Future challenges include optimizing the methods and the vectors of gene delivery.

Managing laboratory automation in a changing pharmaceutical industry

PubMed Central

Rutherford, Michael L.

1995-01-01

The health care reform movement in the USA and increased requirements by regulatory agencies continue to have a major impact on the pharmaceutical industry and the laboratory. Laboratory management is expected to improve effciency by providing more analytical results at a lower cost, increasing customer service, reducing cycle time, while ensuring accurate results and more effective use of their staff. To achieve these expectations, many laboratories are using robotics and automated work stations. Establishing automated systems presents many challenges for laboratory management, including project and hardware selection, budget justification, implementation, validation, training, and support. To address these management challenges, the rationale for project selection and implementation, the obstacles encountered, project outcome, and learning points for several automated systems recently implemented in the Quality Control Laboratories at Eli Lilly are presented. PMID:18925014

Biosonar navigation above water II: exploiting mirror images.

PubMed

Genzel, Daria; Hoffmann, Susanne; Prosch, Selina; Firzlaff, Uwe; Wiegrebe, Lutz

2015-02-15

As in vision, acoustic signals can be reflected by a smooth surface creating an acoustic mirror image. Water bodies represent the only naturally occurring horizontal and acoustically smooth surfaces. Echolocating bats flying over smooth water bodies encounter echo-acoustic mirror images of objects above the surface. Here, we combined an electrophysiological approach with a behavioral experimental paradigm to investigate whether bats can exploit echo-acoustic mirror images for navigation and how these mirrorlike echo-acoustic cues are encoded in their auditory cortex. In an obstacle-avoidance task where the obstacles could only be detected via their echo-acoustic mirror images, most bats spontaneously exploited these cues for navigation. Sonar ensonifications along the bats' flight path revealed conspicuous changes of the reflection patterns with slightly increased target strengths at relatively long echo delays corresponding to the longer acoustic paths from the mirrored obstacles. Recordings of cortical spatiotemporal response maps (STRMs) describe the tuning of a unit across the dimensions of elevation and time. The majority of cortical single and multiunits showed a special spatiotemporal pattern of excitatory areas in their STRM indicating a preference for echoes with (relative to the setup dimensions) long delays and, interestingly, from low elevations. This neural preference could effectively encode a reflection pattern as it would be perceived by an echolocating bat detecting an object mirrored from below. The current study provides both behavioral and neurophysiological evidence that echo-acoustic mirror images can be exploited by bats for obstacle avoidance. This capability effectively supports echo-acoustic navigation in highly cluttered natural habitats. Copyright © 2015 the American Physiological Society.

Computational oncology.

PubMed

Lefor, Alan T

2011-08-01

Oncology research has traditionally been conducted using techniques from the biological sciences. The new field of computational oncology has forged a new relationship between the physical sciences and oncology to further advance research. By applying physics and mathematics to oncologic problems, new insights will emerge into the pathogenesis and treatment of malignancies. One major area of investigation in computational oncology centers around the acquisition and analysis of data, using improved computing hardware and software. Large databases of cellular pathways are being analyzed to understand the interrelationship among complex biological processes. Computer-aided detection is being applied to the analysis of routine imaging data including mammography and chest imaging to improve the accuracy and detection rate for population screening. The second major area of investigation uses computers to construct sophisticated mathematical models of individual cancer cells as well as larger systems using partial differential equations. These models are further refined with clinically available information to more accurately reflect living systems. One of the major obstacles in the partnership between physical scientists and the oncology community is communications. Standard ways to convey information must be developed. Future progress in computational oncology will depend on close collaboration between clinicians and investigators to further the understanding of cancer using these new approaches.

Virtual obstacle crossing: Reliability and differences in stroke survivors who prospectively experienced falls or no falls.

PubMed

Punt, Michiel; Bruijn, Sjoerd M; Wittink, Harriet; van de Port, Ingrid G; Wubbels, Gijs; van Dieën, Jaap H

2017-10-01

Stroke survivors often fall during walking. To reduce fall risk, gait testing and training with avoidance of virtual obstacles is gaining popularity. However, it is unknown whether and how virtual obstacle crossing is associated with fall risk. The present study assessed whether obstacle crossing characteristics are reliable and assessed differences in stroke survivors who prospectively experienced falls or no falls. We recruited twenty-nine community dwelling chronic stroke survivors. Participants crossed five virtual obstacles with increasing lengths. After a break, the test was repeated to assess test-retest reliability. For each obstacle length and trial, we determined; success rate, leading limb preference, pre and post obstacle distance, margins of stability, toe clearance, and crossing step length and speed. Subsequently, fall incidence was monitored using a fall calendar and monthly phone calls over a six-month period. Test-retest reliability was poor, but improved with increasing obstacle-length. Twelve participants reported at least one fall. No association of fall incidence with any of the obstacle crossing characteristics was found. Given the absence of height of the virtual obstacles, obstacle avoidance may have been relatively easy, allowing participants to cross obstacles in multiple ways, increasing variability of crossing characteristics and reducing the association with fall risk. These finding cast some doubt on current protocols for testing and training of obstacle avoidance in stroke rehabilitation. Copyright © 2017 Elsevier B.V. All rights reserved.

Maneuverability and mobility in palm-sized legged robots

NASA Astrophysics Data System (ADS)

Kohut, Nicholas J.; Birkmeyer, Paul M.; Peterson, Kevin C.; Fearing, Ronald S.

2012-06-01

Palm sized legged robots show promise for military and civilian applications, including exploration of hazardous or difficult to reach places, search and rescue, espionage, and battlefield reconnaissance. However, they also face many technical obstacles, including- but not limited to- actuator performance, weight constraints, processing power, and power density. This paper presents an overview of several robots from the Biomimetic Millisystems Laboratory at UC Berkeley, including the OctoRoACH, a steerable, running legged robot capable of basic navigation and equipped with a camera and active tail; CLASH, a dynamic climbing robot; and BOLT, a hybrid crawling and flying robot. The paper also discusses, and presents some preliminary solutions to, the technical obstacles listed above plus issues such as robustness to unstructured environments, limited sensing and communication bandwidths, and system integration.

Resisting the Sirens of Temptation while Studying: Using Reappraisal to Increase Focus, Enthusiasm, and Performance

ERIC Educational Resources Information Center

Leroy, Veronique; Gregoire, Jacques; Magen, Eran; Gross, James J.; Mikolajczak, Moira

2012-01-01

One of the major obstacles in the learning process is temptation, which has the power to divert students from even their most important goals (e.g. getting a degree). In two studies, we tested the hypothesis that cognitive reappraisal could be used to successfully resist temptation. Participants had to memorize tedious material while being tempted…

The politics of paying for health reform: zombies, payroll taxes, and the holy grail.

PubMed

Oberlander, Jonathan

2008-01-01

This paper analyzes the politics of paying for health care reform. It surveys the political strengths and weaknesses of major options to fund universal coverage and explores obstacles to changing how the United States finances health care. Finding a politically viable means to finance universal coverage remains a central barrier to enacting health reform.

Process Challenges in Compound Semiconductors.

DTIC Science & Technology

1988-08-01

dielectric films , and metallization. It became evident during this examination that a major obstacle to the affordable, high-yield manufacture of...in surrounding regions. In both of the structures shown, the curvature of the layers is the characteristic solidification from solution in LPE ...pseudomorphic epitaxial growth is possible only with very thin films in which the structure is strained to match the lattice parameter of the

Predicting the Effects of Ecosystem Management Harvesting Treatments on Breeding Birds in Pine-Hardwood Forests

Treesearch

Lisa J. Petit; Daniel R. Petit; Thomas E. Martin

1993-01-01

Habitat relationships of birds are well known compared to those of other taxa. However, a major obstacle to developing rigorous management plans for birds is the collation and transfer of information from widely scattered technical and academic publications to a form that can be applied directly to the management of species. Recognizing this dilemma, Hamel (1992)...

Paint it Black: One-Step Etch Cuts Solar Cell Costs - Continuum Magazine

Science.gov Websites

quicker, cheaper way to produce large volumes of high-performance PV devices. Cost is a major obstacle for propel PV toward cost-competitiveness. A New Approach to Antireflection Any light reflected from a solar etching large pyramids into the cell surface, add considerable cost to a solar cell-and they succeed only

Inequity in Illinois: How Illogical School Funding Has Eroded Public Education. Special Report

ERIC Educational Resources Information Center

People For the American Way, 2004

2004-01-01

While there are many factors that determine the quality of a public school, inequitable and insufficient school funding is a major obstacle to improving public education for all children. When it comes to funding public education, Illinois has a serious problem. Not only does the state limit its commitment to adequately fund public schools, but it…

School: The Normalizing Factor for Children with Childhood Leukemia. Perspectives of Young Survivors and Their Parents.

ERIC Educational Resources Information Center

Sullivan, Nanci A.; Fulmer, Deborah L.; Zigmond, Naomi

2001-01-01

A study of 8 children (ages 5-7) with Acute Lymphoblastic Leukemia found returning to school was a major milestone and that school serves as the mechanism by which young survivors approach the process of living each day. Attendance obstacles are discussed, along with guidelines for maintaining school as a priority. (Contains references.) (CR)

Art of publication and selection of journal.

PubMed

Singh, Ashish; Singh, Shweta; Mercy, P; Singh, Ajai Kumar; Singh, Deepti; Singh, Manish; Singh, Pratibha

2014-01-01

Publication is both an art and a science. For the beginner, not knowing the intricacies of publication, choice of subject and the appropriate journal to get their work published are major obstacles. In this article, the authors share their experience on how to go about getting an article published and selecting the most suitable journal for publication. They hope this article stimulates medical writing.

Search and Neutralize Factors (CSPGs) that Induce Decline in Transmission to Neurons from Spared Fibers after Chronic Spinal Cord Injury

DTIC Science & Technology

2012-10-01

damaged spinal cord after chronic HX are the result of reduced conduction in uncut axons (Hunanyan et al. 2011). Since elevated level of chondroitin ... sulfate proteoglycans (CSPGs) in the vicinity of the injury has been reported to be a major obstacle for recovery after SCI (Snow et al., 1990; Jones

A Reflection on Distorted Views of Science and Technology in Science Textbooks as Obstacles to the Improvement of Students' Scientific Literacy

ERIC Educational Resources Information Center

Calado, Florbela M.; Bogner, Franz X.

2013-01-01

Scientific literacy has been increasingly considered a major goal of science education. While textbooks remain the most widespread tools for pursuing this goal within classrooms, they have been slow to adapt to the most recent epistemological paradigms, often still conveying distorted views of science and technology. Accordingly, we present herein…

Predictors of the Change in Self-Stigma Following a Single Session of Group Counseling

ERIC Educational Resources Information Center

Wade, Nathaniel G.; Post, Brian C.; Cornish, Marilyn A.; Vogel, David L.; Tucker, Jeritt R.

2011-01-01

One of the major obstacles to seeking psychological help is the stigma associated with counseling and therapy. Self-stigma, the fear of losing self-respect or self-esteem as a result of seeking help, is an important factor in the help-seeking process. In the present study, college students meeting a clinical cutoff for psychological symptoms…

Reconstructing the phylogeny of Scolytinae and close allies: Major obstacles and prospects for a solution

Treesearch

Bjarte H. Jordal

2007-01-01

To enable the resolution of deep phylogenetic divergence in Scolytinae and closely related weevils, several new molecular markers were screened for their phylogenetic potential. The nuclear protein encoding genes, CAD and Arginine Kinase, were particularly promising and will be added to future phylogenetic studies in combination with 28S, COI, and Elongation Factor 1...

Beyond the Limits of the European Higher Education Area: The Case of Belarus

ERIC Educational Resources Information Center

Gille-Belova, Olga

2015-01-01

All European Union (EU) member states and many former post-Soviet countries joined the Bologna Process without major obstacles during the 2000s and today belong to the European Higher Education Area (EHEA). The only European country which was refused membership in the EHEA was Belarus, whose demand was rejected in 2012. The case study of this…

Lack of Follow-Up Exams after Failed School Vision Screenings: An Investigation of Contributing Factors

ERIC Educational Resources Information Center

Kimel, Linda S.

2006-01-01

Programs to facilitate professional eye exams after failed school vision screenings often are based on the assumption that funding and access to services are major obstacles to care. Despite such programs, many children do not receive professional exams. The purpose of this study was to identify additional barriers to follow-up eye care. School…

Factors Related to Teachers' Attitudes towards the Inclusive Education of Students with Severe Intellectual Disabilities in Riyadh, Saudi

ERIC Educational Resources Information Center

Alquraini, Turki A.

2012-01-01

In Saudi Arabia, the majority of students with severe intellectual disabilities are still educated in special schools that do not meet their unique needs for interaction with their typically developing peers in public schools settings where they could improve social, communication and academic skills. One of the most significant obstacles to…

Getting Girls out of Work and into School. Policy Brief

ERIC Educational Resources Information Center

Spence, Nancy

2006-01-01

Records show that school enrollment for girls is still lagging behind in some areas in the Asia and Pacific region, which poses challenge for the region to achieve Education for All (EFA) by 2015. And girls' labor in the Asia and Pacific region continues to constitute a major obstacle towards gender parity in education, another EFA target. Girls'…

Why medical savings accounts deserve a closer look.

PubMed

Jensen, G A; Morlock, R J

1994-01-01

Dismissed as a luxury only for the young or wealthy, medical savings accounts could be used by a majority of Americans--who are neither poor or chronically ill--to make cost-conscious choices about their health care. Current federal tax laws and insurers' inability to sell catastrophic group coverage policies pose obstacles to their widespread use and should be removed.

Obstacles to engaging in young driver licensing: Perspectives of parents.

PubMed

Naz, Sehana; Scott-Parker, Bridie

2017-02-01

Young novice drivers remain at greater risk of injury and death despite a wealth of interventions including graduated driver licensing (GDL) programs. The key to implementing safer practices inherent in GDL appears to lie with optimising the role of parents. This qualitative research explored the parent's perspectives of obstacles to engaging in the driver licensing process within a GDL program. Parents also shared advice on what they found helpful, and where relevant, recommended changes in the process to enable safer practices for young drivers. Twenty-three parents (aged 35-60 years, M=49.52, SD=8.01, 11 males) participated in semi-structured interviews regarding licensing experiences with their young driver children. The young drivers included learner (n=11), provisional (restricted/intermediate) (n=9) and open (unrestricted/full) licence drivers (n=3), ranging from 16 to 24 years (M=18.04, SD=2.21, 13 males). Content analysis revealed that most obstacles were encountered at the learner licensing phase, with the parent-reported difficult temperament of the learner driver the most prominent. Unsurprisingly, advice to other parents to be patient and remain calm featured heavily during the same phase. Anxiety from not having control of the vehicle was another obstacle at the learner phase, translating to anxieties for child safety in the early stages of provisional driving. Recommendations for the current GDL included more rigorous road rule testing, with general support for the program, professional driver training at learner and provisional stages facilitated parental engagement through the licensing phases. The findings overwhelmingly suggest a need for parents to be educated regarding their importance in, and of, the driver licensing process, and the efficacy of their instruction, content and practices. Copyright © 2016 Elsevier Ltd. All rights reserved.

Analysis and design of a capsule landing system and surface vehicle control system for Mars exporation

NASA Technical Reports Server (NTRS)

Frederick, D. K.; Lashmet, P. K.; Sandor, G. N.; Shen, C. N.; Smith, E. J.; Yerazunis, S. W.

1972-01-01

The problems related to the design and control of a mobile planetary vehicle to implement a systematic plan for the exploration of Mars were investigated. Problem areas receiving attention include: vehicle configuration, control, dynamics, systems and propulsion; systems analysis; navigation, terrain modeling and path selection; and chemical analysis of specimens. The following specific tasks were studied: vehicle model design, mathematical modeling of dynamic vehicle, experimental vehicle dynamics, obstacle negotiation, electromechanical controls, collapsibility and deployment, construction of a wheel tester, wheel analysis, payload design, system design optimization, effect of design assumptions, accessory optimal design, on-board computer subsystem, laser range measurement, discrete obstacle detection, obstacle detection systems, terrain modeling, path selection system simulation and evaluation, gas chromatograph/mass spectrometer system concepts, chromatograph model evaluation and improvement and transport parameter evaluation.

Analysis and design of a capsule landing system and surface vehicle control system for Mars exploration

NASA Technical Reports Server (NTRS)

Frederick, D. K.; Lashmet, P. K.; Sandor, G. N.; Shen, C. N.; Smith, E. J.; Yerazunis, S. W.

1972-01-01

Investigation of problems related to the design and control of a mobile planetary vehicle to implement a systematic plan for the exploration of Mars has been undertaken. Problem areas receiving attention include: vehicle configuration, control, dynamics, systems and propulsion; systems analysis; terrain modeling and path selection; and chemical analysis of specimens. The following specific tasks have been under study: vehicle model design, mathematical modeling of a dynamic vehicle, experimental vehicle dynamics, obstacle negotiation, electromechanical controls, collapsibility and deployment, construction of a wheel tester, wheel analysis, payload design, system design optimization, effect of design assumptions, accessory optimal design, on-board computer sybsystem, laser range measurement, discrete obstacle detection, obstacle detection systems, terrain modeling, path selection system simulation and evaluation, gas chromatograph/mass spectrometer system concepts, chromatograph model evaluation and improvement.

A Real-Time Reaction Obstacle Avoidance Algorithm for Autonomous Underwater Vehicles in Unknown Environments.

PubMed

Yan, Zheping; Li, Jiyun; Zhang, Gengshi; Wu, Yi

2018-02-02

A novel real-time reaction obstacle avoidance algorithm (RRA) is proposed for autonomous underwater vehicles (AUVs) that must adapt to unknown complex terrains, based on forward looking sonar (FLS). To accomplish this algorithm, obstacle avoidance rules are planned, and the RRA processes are split into five steps Introduction only lists 4 so AUVs can rapidly respond to various environment obstacles. The largest polar angle algorithm (LPAA) is designed to change detected obstacle's irregular outline into a convex polygon, which simplifies the obstacle avoidance process. A solution is designed to solve the trapping problem existing in U-shape obstacle avoidance by an outline memory algorithm. Finally, simulations in three unknown obstacle scenes are carried out to demonstrate the performance of this algorithm, where the obtained obstacle avoidance trajectories are safety, smooth and near-optimal.

Stepping back to see the big picture: when obstacles elicit global processing.

PubMed

Marguc, Janina; Förster, Jens; Van Kleef, Gerben A

2011-11-01

Can obstacles prompt people to look at the "big picture" and open up their minds? Do the cognitive effects of obstacles extend beyond the tasks with which they interfere? These questions were addressed in 6 studies involving both physical and nonphysical obstacles and different measures of global versus local processing styles. Perceptual scope increased after participants solved anagrams in the presence, rather than the absence, of an auditory obstacle (random words played in the background; Study 1), particularly among individuals low in volatility (i.e., those who are inclined to stay engaged and finish what they do; Study 4). It also increased immediately after participants encountered a physical obstacle while navigating a maze (Study 3A) and when compared with doing nothing (Study 3B). Conceptual scope increased after participants solved anagrams while hearing random numbers framed as an "obstacle to overcome" rather than a "distraction to ignore" (Study 2) and after participants navigated a maze with a physical obstacle, compared with a maze without a physical obstacle, but only when trait (Study 5) or state (Study 6) volatility was low. Results suggest that obstacles trigger an "if obstacle, then start global processing" response, primarily when people are inclined to stay engaged and finish ongoing activities. Implications for dealing with life's obstacles and related research are discussed.

Mechanical energy assessment of adult with Down syndrome during walking with obstacle avoidance.

PubMed

Salami, Firooz; Vimercati, Sara Laura; Rigoldi, Chiara; Taebi, Amirtaha; Albertini, Giorgio; Galli, Manuela

2014-08-01

The aim of this study is analyzing the differences between plane walking and stepping over an obstacle for two groups of healthy people and people with Down syndrome and then, evaluating the movement efficiency between the groups by comprising of their mechanical energy exchanges. 39 adults including two groups of 21 people with Down syndrome (age: 21.6 ± 7 years) and 18 healthy people (age: 25.1 ± 2.4 years) participated in this research. The test has been done in two conditions, first in plane walking and second in walking with an obstacle (10% of the subject's height). The gait data were acquired using quantitative movement analysis, composed of an optoelectronic system (Elite2002, BTS) with eight infrared cameras. Mechanical energy exchanges are computed by dedicated software and finally the data including spatiotemporal parameters, mechanical energy parameters and energy recovery of gait cycle are analyzed by statistical software to find significant differences. Regards to spatiotemporal parameters velocity and step length are lower in people with Down syndrome. Mechanical energy parameters particularly energy recovery does not change from healthy people to people with Down syndrome. However, there are some differences in inter-group through plane walking to obstacle avoidance and it means people with Down syndrome probably use their residual abilities in the most efficient way to achieve the main goal of an efficient energy recovery. Copyright © 2014 Elsevier Ltd. All rights reserved.

Predicting the influence of long-range molecular interactions on macroscopic-scale diffusion by homogenization of the Smoluchowski equation

NASA Astrophysics Data System (ADS)

Kekenes-Huskey, P. M.; Gillette, A. K.; McCammon, J. A.

2014-05-01

The macroscopic diffusion constant for a charged diffuser is in part dependent on (1) the volume excluded by solute "obstacles" and (2) long-range interactions between those obstacles and the diffuser. Increasing excluded volume reduces transport of the diffuser, while long-range interactions can either increase or decrease diffusivity, depending on the nature of the potential. We previously demonstrated [P. M. Kekenes-Huskey et al., Biophys. J. 105, 2130 (2013)] using homogenization theory that the configuration of molecular-scale obstacles can both hinder diffusion and induce diffusional anisotropy for small ions. As the density of molecular obstacles increases, van der Waals (vdW) and electrostatic interactions between obstacle and a diffuser become significant and can strongly influence the latter's diffusivity, which was neglected in our original model. Here, we extend this methodology to include a fixed (time-independent) potential of mean force, through homogenization of the Smoluchowski equation. We consider the diffusion of ions in crowded, hydrophilic environments at physiological ionic strengths and find that electrostatic and vdW interactions can enhance or depress effective diffusion rates for attractive or repulsive forces, respectively. Additionally, we show that the observed diffusion rate may be reduced independent of non-specific electrostatic and vdW interactions by treating obstacles that exhibit specific binding interactions as "buffers" that absorb free diffusers. Finally, we demonstrate that effective diffusion rates are sensitive to distribution of surface charge on a globular protein, Troponin C, suggesting that the use of molecular structures with atomistic-scale resolution can account for electrostatic influences on substrate transport. This approach offers new insight into the influence of molecular-scale, long-range interactions on transport of charged species, particularly for diffusion-influenced signaling events occurring in crowded cellular environments.

Obstacles for Teachers to Integrate Technology with Instruction

ERIC Educational Resources Information Center

Alenezi, Abdullah

2017-01-01

This paper covers type one and two educational obstacles in using technology in the classrooms, and considering those obstacles tries to find the answer to the following overarching research question which can help to gauge some obstacles for the educational technology integration for elementary and high school education: What obstacles do…

Influences of periodic mechanical deformation on pinned spiral waves

NASA Astrophysics Data System (ADS)

Chen, Jiang-Xing; Peng, Liang; Zheng, Qiang; Zhao, Ye-Hua; Ying, He-Ping

2014-09-01

In a generic model of excitable media, we study the behavior of spiral waves interacting with obstacles and their dynamics under the influences of simple periodic mechanical deformation (PMD). Depending on the characteristics of the obstacles, i.e., size and excitability, the rotation of a pinned spiral wave shows different scenarios, e.g., embedding into or anchoring on an obstacle. Three different drift phenomena induced by PMD are observed: scattering on small partial-excitable obstacles, meander-induced unpinning on big partial-excitable obstacles, and drifting around small unexcitable obstacles. Their underlying mechanisms are discussed. The dependence of the threshold amplitude of PMD on the characteristics of the obstacles to successfully remove pinned spiral waves on big partial-excitable obstacles is studied.

Vision Based Obstacle Detection in Uav Imaging

NASA Astrophysics Data System (ADS)

Badrloo, S.; Varshosaz, M.

2017-08-01

Detecting and preventing incidence with obstacles is crucial in UAV navigation and control. Most of the common obstacle detection techniques are currently sensor-based. Small UAVs are not able to carry obstacle detection sensors such as radar; therefore, vision-based methods are considered, which can be divided into stereo-based and mono-based techniques. Mono-based methods are classified into two groups: Foreground-background separation, and brain-inspired methods. Brain-inspired methods are highly efficient in obstacle detection; hence, this research aims to detect obstacles using brain-inspired techniques, which try to enlarge the obstacle by approaching it. A recent research in this field, has concentrated on matching the SIFT points along with, SIFT size-ratio factor and area-ratio of convex hulls in two consecutive frames to detect obstacles. This method is not able to distinguish between near and far obstacles or the obstacles in complex environment, and is sensitive to wrong matched points. In order to solve the above mentioned problems, this research calculates the dist-ratio of matched points. Then, each and every point is investigated for Distinguishing between far and close obstacles. The results demonstrated the high efficiency of the proposed method in complex environments.

Strategies for obstacle avoidance during walking in the cat.

PubMed

Chu, Kevin M I; Seto, Sandy H; Beloozerova, Irina N; Marlinski, Vladimir

2017-08-01

Avoiding obstacles is essential for successful navigation through complex environments. This study aimed to clarify what strategies are used by a typical quadruped, the cat, to avoid obstacles during walking. Four cats walked along a corridor 2.5 m long and 25 or 15 cm wide. Obstacles, small round objects 2.5 cm in diameter and 1 cm in height, were placed on the floor in various locations. Movements of the paw were recorded with a motion capture and analysis system (Visualeyez, PTI). During walking in the wide corridor, cats' preferred strategy for avoiding a single obstacle was circumvention, during which the stride direction changed while stride duration and swing-to-stride duration ratio were preserved. Another strategy, stepping over the obstacle, was used during walking in the narrow corridor, when lateral deviations of walking trajectory were restricted. Stepping over the obstacle involved changes in two consecutive strides. The stride preceding the obstacle was shortened, and swing-to-stride ratio was reduced. The obstacle was negotiated in the next stride of increased height and normal duration and swing-to-stride ratio. During walking on a surface with multiple obstacles, both strategies were used. To avoid contact with the obstacle, cats placed the paw away from the object at a distance roughly equal to the diameter of the paw. During obstacle avoidance cats prefer to alter muscle activities without altering the locomotor rhythm. We hypothesize that a choice of the strategy for obstacle avoidance is determined by minimizing the complexity of neuro-motor processes required to achieve the behavioral goal. NEW & NOTEWORTHY In a study of feline locomotor behavior we found that the preferred strategy to avoid a small obstacle is circumvention. During circumvention, stride direction changes but length and temporal structure are preserved. Another strategy, stepping over the obstacle, is used in narrow walkways. During overstepping, two strides adjust. A stride preceding the obstacle decreases in length and duration. The following stride negotiating the obstacle increases in height while retaining normal temporal structure and nearly normal length. Copyright © 2017 the American Physiological Society.

Internet Implementation in Brazilian K-12 Schools.

ERIC Educational Resources Information Center

Joia, Luiz Antonio

1997-01-01

Presents a framework for implementing the Internet in Brazilian elementary and secondary schools. Topics include schools as assembly lines in the information society; pedagogical uses of the Internet, including research, educational projects, and video conferences; and obstacles to implementing the Internet, including cost, cultural differences,…

Fusing terrain and goals: agent control in urban environments

NASA Astrophysics Data System (ADS)

Kaptan, Varol; Gelenbe, Erol

2006-04-01

The changing face of contemporary military conflicts has forced a major shift of focus in tactical planning and evaluation from the classical Cold War battlefield to an asymmetric guerrilla-type warfare in densely populated urban areas. The new arena of conflict presents unique operational difficulties due to factors like complex mobility restrictions and the necessity to preserve civilian lives and infrastructure. In this paper we present a novel method for autonomous agent control in an urban environment. Our approach is based on fusing terrain information and agent goals for the purpose of transforming the problem of navigation in a complex environment with many obstacles into the easier problem of navigation in a virtual obstacle-free space. The main advantage of our approach is its ability to act as an adapter layer for a number of efficient agent control techniques which normally show poor performance when applied to an environment with many complex obstacles. Because of the very low computational and space complexity at runtime, our method is also particularly well suited for simulation or control of a huge number of agents (military as well as civilian) in a complex urban environment where traditional path-planning may be too expensive or where a just-in-time decision with hard real-time constraints is required.

Gait Pattern Alterations during Walking, Texting and Walking and Texting during Cognitively Distractive Tasks while Negotiating Common Pedestrian Obstacles

PubMed Central

Licence, Sammy; Smith, Robynne; McGuigan, Miranda P.; Earnest, Conrad P.

2015-01-01

Objectives Mobile phone texting is a common daily occurrence with a paucity of research examining corresponding gait characteristics. To date, most studies have participants walk in a straight line vs. overcoming barriers and obstacles that occur during regular walking. The aim of our study is to examine the effect of mobile phone texting during periods of cognitive distraction while walking and negotiating barriers synonymous with pedestrian traffic. Methods Thirty participants (18-50y) completed three randomized, counter-balanced walking tasks over a course during: (1) normal walking (control), (2) texting and walking, and (3) texting and walking whilst being cognitively distraction via a standard mathematical test performed while negotiating the obstacle course. We analyzed gait characteristics during course negotiation using a 3-dimensional motion analysis system and a general linear model and Dunnet-Hsu post-hoc procedure the normal walking condition to assess gait characteristic differences. Primary outcomes included the overall time to complete the course time and barrier contact. Secondary outcomes included obstacle clearance height, step frequency, step time, double support phase and lateral deviation. Results Participants took significantly longer (mean ± SD) to complete the course while texting (24.96±4.20 sec) and during cognitive distraction COG (24.09±3.36 sec) vs. normal walking (19.32±2.28 sec; all, P<0.001). No significant differences were noted for barrier contacts (P = 0.28). Step frequency, step time, double support phase and lateral deviation all increased in duration during the texting and cognitive distraction trial. Texting and being cognitively distracted also increased obstacle clearance versus the walking condition (all, P<0.02). Conclusions Texting while walking and/or being cognitively distracted significantly affect gait characteristics concordant to mobile phone usage resulting in a more cautious gate pattern. Future research should also examine a similar study in older participants who may be at a greater risk of tripping with such walking deviations. PMID:26222430

Aviation obstacle auto-extraction using remote sensing information

NASA Astrophysics Data System (ADS)

Zimmer, N.; Lugsch, W.; Ravenscroft, D.; Schiefele, J.

2008-10-01

An Obstacle, in the aviation context, may be any natural, man-made, fixed or movable object, permanent or temporary. Currently, the most common way to detect relevant aviation obstacles from an aircraft or helicopter for navigation purposes and collision avoidance is the use of merged infrared and synthetic information of obstacle data. Several algorithms have been established to utilize synthetic and infrared images to generate obstacle information. There might be a situation however where the system is error-prone and may not be able to consistently determine the current environment. This situation can be avoided when the system knows the true position of the obstacle. The quality characteristics of the obstacle data strongly depends on the quality of the source data such as maps and official publications. In some countries such as newly industrializing and developing countries, quality and quantity of obstacle information is not available. The aviation world has two specifications - RTCA DO-276A and ICAO ANNEX 15 Ch. 10 - which describe the requirements for aviation obstacles. It is essential to meet these requirements to be compliant with the specifications and to support systems based on these specifications, e.g. 3D obstacle warning systems where accurate coordinates based on WGS-84 is a necessity. Existing aerial and satellite or soon to exist high quality remote sensing data makes it feasible to think about automated aviation obstacle data origination. This paper will describe the feasibility to auto-extract aviation obstacles from remote sensing data considering limitations of image and extraction technologies. Quality parameters and possible resolution of auto-extracted obstacle data will be discussed and presented.

Workarounds and obstacles: unexpected source of innovation.

PubMed

Lalley, Cathy

2014-01-01

Nurse leaders are aware that nurses are finding ways to adapt health information technology to patient care activities. Previous literature has presented nurses' response to technology obstacles as a work-around, characterized as a negative behavior. Using narrative inquiry, this article examines 9 direct care nurses' interactions on a medical/surgical/telemetry unit. Specifically, nurses' encounters with technology obstacles will be addressed from a complexity science perspective. Four support staff including the clinical nurse manager, pharmacist, quality nurse, and project manager who is also a nurse were interviewed as part of data collection. Complexity science provides nurse leaders' insight into nurses' behavior where outcomes emerge from tensions in the environment through multidirectional and self-organizing interactions. Innovation was found when nurses responded to health information technology obstacles with self-organizing interactions, sensitivity to initial conditions, and multidirectionality. Their actions were also influenced by many sets of rules. Nurses self-organized with coworkers to find better ways to deliver care to patients when using technology. Opportunities exist for nurse leaders to facilitate interactions among nurses and other members of the organization to realize better use of health information technology that improves the patient experience.

Development of a program for tele-rehabilitation of COPD patients across sectors: co-innovation in a network

PubMed Central

Dinesen, Birthe; Seeman, Janne; Gustafsson, Jeppe

2011-01-01

Introduction The aim of the Telekat project is to prevent re-admissions of patients with chronic obstructive pulmonary disease (COPD) by developing a preventive program of tele-rehabilitation across sectors for COPD patients. The development of the program is based on a co-innovation process between COPD patients, relatives, healthcare professionals and representatives from private firms and universities. This paper discusses the obstacles that arise in the co-innovation process of developing an integrated technique for tele-rehabilitation of COPD patients. Theory Network and innovation theory. Methods The case study was applied. A triangulation of data collection techniques was used: documents, observations (123 hours), qualitative interviews (n=32) and action research. Findings Obstacles were identified in the network context; these obstacles included the mindset of the healthcare professionals, inter-professionals relations, views of technology as a tool and competing visions for the goals of tele-rehabilitation. Conclusion We have identified obstacles that emerge in the co-innovation process when developing a programme for tele-rehabilitation of COPD patients in an inter-organizational context. Action research has been carried out and can have helped to facilitate the co-innovation process. PMID:21637709

Toward autonomous driving: The CMU Navlab. I - Perception

NASA Technical Reports Server (NTRS)

Thorpe, Charles; Hebert, Martial; Kanade, Takeo; Shafer, Steven

1991-01-01

The Navlab project, which seeks to build an autonomous robot that can operate in a realistic environment with bad weather, bad lighting, and bad or changing roads, is discussed. The perception techniques developed for the Navlab include road-following techniques using color classification and neural nets. These are discussed with reference to three road-following systems, SCARF, YARF, and ALVINN. Three-dimensional perception using three types of terrain representation (obstacle maps, terrain feature maps, and high-resolution maps) is examined. It is noted that perception continues to be an obstacle in developing autonomous vehicles.

Test-Wave Measurements of Microwave Absorption Efficiency in a Planar Surface-Wave Plasma Reactor

NASA Astrophysics Data System (ADS)

Ghanashev, Ivan; Morita, Shin; \\scToyoda, Naoki; Nagatsu, Masaaki; Sugai, Hideo

1999-07-01

A major obstacle for experimental surface-wave (SW) excitationand propagation studies in SW plasma is the self-consistentbehaviour of the latter, which does not permit continuousvariation of the electron density ne. In the presentstudy, we demonstrate how this obstacle can be overcome by anindependent plasma source, in our case, an inductively coupledplasma (ICP) created by a high-power RF (13.56 MHz) generator.Through a rectangular waveguide short-circuited at its end by amovable plunger, we introduced into the ICP a weak (powerless than 20 W) nonionising 2.4 GHz microwave.This permitted us to highlight important SW excitation andpropagation phenomena. In particular, we confirmed the existenceof the predicted [Jpn. J. Appl. Phys. 36 (1997) 4704]resonance minima in the ne dependence of the powerreflection coefficient. The influence of the plunger positionon the chamber matching was studied systematically and fourdifferent coupling aperture geometries were compared.

AST Combustion Workshop: Diagnostics Working Group Report

NASA Technical Reports Server (NTRS)

Locke, Randy J.; Hicks, Yolanda R.; Hanson, Ronald K.

1996-01-01

A workshop was convened under NASA's Advanced Subsonics Technologies (AST) Program. Many of the principal combustion diagnosticians from industry, academia, and government laboratories were assembled in the Diagnostics/Testing Subsection of this workshop to discuss the requirements and obstacles to the successful implementation of advanced diagnostic techniques to the test environment of the proposed AST combustor. The participants, who represented the major relevant areas of advanced diagnostic methods currently applied to combustion and related fields, first established the anticipated AST combustor flowfield conditions. Critical flow parameters were then examined and prioritized as to their importance to combustor/fuel injector design and manufacture, environmental concerns, and computational interests. Diagnostic techniques were then evaluated in terms of current status, merits and obstacles for each flow parameter. All evaluations are presented in tabular form and recommendations are made on the best-suited diagnostic method to implement for each flow parameter in order of applicability and intrinsic value.

Intelligent walkers for the elderly: performance and safety testing of VA-PAMAID robotic walker.

PubMed

Rentschler, Andrew J; Cooper, Rory A; Blasch, Bruce; Boninger, Michael L

2003-01-01

A walker that could help navigate and avoid collisions with obstacles could help reduce health costs and increase the quality of care and independence of thousands of people. This study evaluated the safety and performance of the Veterans Affairs Personal Adaptive Mobility Aid (VA-PAMAID). We performed engineering tests on the VA-PAMAID to determine safety factors, including stability, energy consumption, fatigue life, and sensor and control malfunctions. The VA-PAMAID traveled 10.9 km on a full charge and avoided obstacles while traveling at a speed of up to 1.2 m/s. No failures occurred during static stability, climatic, or fatigue testing. Some problems were encountered during obstacle climbing and sensor and control testing. The VA-PAMAID has good range, has adequate reaction time, and is structurally sound. Clinical trials are planned to compare the device to other low-technical adaptive mobility devices.

Wakes from submerged obstacles in an open channel flow

NASA Astrophysics Data System (ADS)

Smith, Geoffrey B.; Marmorino, George; Dong, Charles; Miller, W. D.; Mied, Richard

2015-11-01

Wakes from several submerged obstacles are examined via airborne remote sensing. The primary focus will be bathymetric features in the tidal Potomac river south of Washington, DC, but others may be included as well. In the Potomac the water depth is nominally 10 m with an obstacle height of 8 m, or 80% of the depth. Infrared imagery of the water surface reveals thermal structure suitable both for interpretation of the coherent structures and for estimating surface currents. A novel image processing technique is used to generate two independent scenes with a known time offset from a single overpass from the infrared imagery, suitable for velocity estimation. Color imagery of the suspended sediment also shows suitable texture. Both the `mountain wave' regime and a traditional turbulent wake are observed, depending on flow conditions. Results are validated with in-situ ADCP transects. A computational model is used to further interpret the results.

The MITy micro-rover: Sensing, control, and operation

NASA Technical Reports Server (NTRS)

Malafeew, Eric; Kaliardos, William

1994-01-01

The sensory, control, and operation systems of the 'MITy' Mars micro-rover are discussed. It is shown that the customized sun tracker and laser rangefinder provide internal, autonomous dead reckoning and hazard detection in unstructured environments. The micro-rover consists of three articulated platforms with sensing, processing and payload subsystems connected by a dual spring suspension system. A reactive obstacle avoidance routine makes intelligent use of robot-centered laser information to maneuver through cluttered environments. The hazard sensors include a rangefinder, inclinometers, proximity sensors and collision sensors. A 486/66 laptop computer runs the graphical user interface and programming environment. A graphical window displays robot telemetry in real time and a small TV/VCR is used for real time supervisory control. Guidance, navigation, and control routines work in conjunction with the mapping and obstacle avoidance functions to provide heading and speed commands that maneuver the robot around obstacles and towards the target.

The effects of bound state motion on macromolecular diffusion

NASA Astrophysics Data System (ADS)

Hough, Loren; Stefferson, Michael; Norris, Samantha; Maguire, Laura; Vernerey, Franck; Betterton, Meredith

The diffusion of macromolecules is modified in crowded environments by both inert obstacles and interaction sites. Molecules are generally slowed in their movement inducing transient anomalous subdiffusion. Obstacles also modify the kinetics and equilibrium behavior of interaction between mobile proteins. In some biophysical contexts, bound molecules can still experience mobility, for example transcription factors sliding along DNA, membrane proteins with some entry and diffusion within lipid domains, or proteins that can enter into non-membrane bound compartments such as the nucleolus. We used lattice and continuum models to study the diffusive behavior of tracer particles which bind to obstacles and can diffuse within them. We show that binding significantly alters the motion of tracers. The type and degree of motion while bound is a key determinant of the tracer mobility. Our work has implications for protein-protein movement and interactions within living cells, including those involving intrinsically disordered proteins.

Cooperative Environment Scans Based on a Multi-Robot System

PubMed Central

Kwon, Ji-Wook

2015-01-01

This paper proposes a cooperative environment scan system (CESS) using multiple robots, where each robot has low-cost range finders and low processing power. To organize and maintain the CESS, a base robot monitors the positions of the child robots, controls them, and builds a map of the unknown environment, while the child robots with low performance range finders provide obstacle information. Even though each child robot provides approximated and limited information of the obstacles, CESS replaces the single LRF, which has a high cost, because much of the information is acquired and accumulated by a number of the child robots. Moreover, the proposed CESS extends the measurement boundaries and detects obstacles hidden behind others. To show the performance of the proposed system and compare this with the numerical models of the commercialized 2D and 3D laser scanners, simulation results are included. PMID:25789491

Research on UAV Intelligent Obstacle Avoidance Technology During Inspection of Transmission Line

NASA Astrophysics Data System (ADS)

Wei, Chuanhu; Zhang, Fei; Yin, Chaoyuan; Liu, Yue; Liu, Liang; Li, Zongyu; Wang, Wanguo

Autonomous obstacle avoidance of unmanned aerial vehicle (hereinafter referred to as UAV) in electric power line inspection process has important significance for operation safety and economy for UAV intelligent inspection system of transmission line as main content of UAV intelligent inspection system on transmission line. In the paper, principles of UAV inspection obstacle avoidance technology of transmission line are introduced. UAV inspection obstacle avoidance technology based on particle swarm global optimization algorithm is proposed after common obstacle avoidance technologies are studied. Stimulation comparison is implemented with traditional UAV inspection obstacle avoidance technology which adopts artificial potential field method. Results show that UAV inspection strategy of particle swarm optimization algorithm, adopted in the paper, is prominently better than UAV inspection strategy of artificial potential field method in the aspects of obstacle avoidance effect and the ability of returning to preset inspection track after passing through the obstacle. An effective method is provided for UAV inspection obstacle avoidance of transmission line.

Undocumented Immigrants and State Higher Education Policy: The Politics of In-State Tuition Eligibility in Texas and Arizona

ERIC Educational Resources Information Center

Dougherty, Kevin J.; Nienhusser, H. Kenny; Vega, Blanca E.

2010-01-01

Every year about 65,000 undocumented students graduate from U.S. high schools. A major obstacle to their attending college is not being eligible for in-state tuition. Today, nine states permit it while four prohibit it. Even if the federal DREAM Act passes, state policy decisions will continue to strongly shape college opportunities for…

Population structure and genetic diversity in North American Hedysarum boreale Nutt.

Treesearch

Bradley S. Bushman; Steven R. Larson; Michael D. Peel; Michael E. Pfrender

2007-01-01

Hedysarum boreale Nutt. is a perennial legume native to western North America, with robust foliage in the late spring season. Due to its wide native range, forage value, and N2 fixation, H. boreale is of interest for rangeland revegetation and production. Seed cost is a major obstacle for utilization of H. boreale, primarily due to seed shattering and unreliable seed...

Convergent and Discriminant Validity of the Autism Spectrum Disorder-Problem Behavior for Children (ASD-PBC) against the Behavioral Assessment System for Children, Second Edition (BASC-2)

ERIC Educational Resources Information Center

Mahan, Sara; Matson, Johnny L.

2011-01-01

Many children with Autism Spectrum Disorder (ASD) demonstrate challenging behaviors. Since challenging behaviors are obstacles for social development and learning, it is important to determine if and what challenging behaviors are exhibited. Although there are some measures that asses for challenging behaviors, the majority were not specifically…

Using Commercially Available Techniques to Make Organic Chemistry Representations Tactile and More Accessible to Students with Blindness or Low Vision

ERIC Educational Resources Information Center

Supalo, Cary A.; Kennedy, Sean H.

2014-01-01

Organic chemistry courses can present major obstacles to access for students with blindness or low vision (BLV). In recent years, efforts have been made to represent organic chemistry concepts in tactile forms for blind students. These methodologies are described in this manuscript. Further work being done at Illinois State University is also…

Self-Reports of Child Maltreatment in the U.S.: A Key Social Indicator

ERIC Educational Resources Information Center

Kesner, John E.

2007-01-01

A key social indicator of the well being of a society is the health and welfare of their children. Child maltreatment is a major problem in the U.S. and the world and the reporting of maltreatment has been the subject of much research and debate. However, little is known about self-reports of child maltreatment. Children face many obstacles that…

Jana: Confidential Communications on Social Networks

DTIC Science & Technology

2017-08-09

Report: Jana: Confidential Communications on Social Networks The views, opinions and/or findings contained in this report are those of the author(s) and...Confidential Communications on Social Networks Report Term: 0-Other Email: krish@ucr.edu Distribution Statement: 1-Approved for public release; distribution...is unlimited. Major Goals: The inability of users to communicate secretly on online social networking (OSN) platforms is a key obstacle to overcome

History and Status of the CIS Customs Union

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

Lawson, T.M.; Erickson, S.A.

1999-08-31

This report explores the history of the CIS Customs Union and the major obstacles the Union faces in its implementation. Investigation of the Customs Union is necessary as its implementation could effect the Second Line of Defense (SLD) Program. Russian Customs contends that radiation detectors should not be installed along the Customs Union members borders of as the borders will be dissolved when the Union is implemented.

Japan Report

DTIC Science & Technology

1987-05-06

media they were stopped. The greatest obstacle concerned the intentions of the United States’ Ford Motor Company, which is a major Mazda ...system of checks on various types of management planning. Because of this, the Mazda chief has reported to Ford in regards to their cooperation...bothered Chrysler’s rival, Ford . Difficulties arose here and thus Mazda rejected the cooperation proposal. However, it is not true that the plan for

A Hybrid Model for IT Investment Analysis: Application to RFID Adoption in the Retail Sector

ERIC Educational Resources Information Center

Kasiri, Narges A.

2010-01-01

Scope and Method of Study. One of the major obstacles in Information Technology (IT) adoption is its return on investment analysis. IT benefits in organizations are hard to measure and are usually realized over time. System dynamics approach has been used in IT literature to identify the impact of IT on business processes. Given benefits of any IT…

Assisted Repeated Reading with an Advanced-Level Japanese EFL Reader: A Longitudinal Diary Study

ERIC Educational Resources Information Center

Taguchi, Etsuo; Gorsuch, Greta; Takayasu-Maass, Miyoko; Snipp, Kirsten

2012-01-01

Reading fluency has attracted the attention of reading researchers and educators since the early 1970s and has become a priority issue in English as a first language (L1) settings. It has also become a critical issue in English as a second or foreign language (L2) settings because the lack of fluency is considered a major obstacle to developing…

Economic Dimensions of Civil Conflicts

DTIC Science & Technology

2012-09-01

international system after the Cold War , due to changes in the nature of war , and globalization. First , before the Cold War , insurgent movements were dependent...socialist and post-secession transitions.121 First , the civil war and NATO’s air bombardment devastated the country and an already crippled economic...Uncertainty The devastation of war , a volatile security environment and political uncertainty were the first major obstacles for post-conflict economic

A Real-Time Reaction Obstacle Avoidance Algorithm for Autonomous Underwater Vehicles in Unknown Environments

PubMed Central

Yan, Zheping; Li, Jiyun; Zhang, Gengshi; Wu, Yi

2018-01-01

A novel real-time reaction obstacle avoidance algorithm (RRA) is proposed for autonomous underwater vehicles (AUVs) that must adapt to unknown complex terrains, based on forward looking sonar (FLS). To accomplish this algorithm, obstacle avoidance rules are planned, and the RRA processes are split into five steps Introduction only lists 4 so AUVs can rapidly respond to various environment obstacles. The largest polar angle algorithm (LPAA) is designed to change detected obstacle’s irregular outline into a convex polygon, which simplifies the obstacle avoidance process. A solution is designed to solve the trapping problem existing in U-shape obstacle avoidance by an outline memory algorithm. Finally, simulations in three unknown obstacle scenes are carried out to demonstrate the performance of this algorithm, where the obtained obstacle avoidance trajectories are safety, smooth and near-optimal. PMID:29393915

Transition operators in electromagnetic-wave diffraction theory. II - Applications to optics

NASA Technical Reports Server (NTRS)

Hahne, G. E.

1993-01-01

The theory developed by Hahne (1992) for the diffraction of time-harmonic electromagnetic waves from fixed obstacles is briefly summarized and extended. Applications of the theory are considered which comprise, first, a spherical harmonic expansion of the so-called radiation impedance operator in the theory, for a spherical surface, and second, a reconsideration of familiar short-wavelength approximation from the new standpoint, including a derivation of the so-called physical optics method on the basis of quasi-planar approximation to the radiation impedance operator, augmented by the method of stationary phase. The latter includes a rederivation of the geometrical optics approximation for the complete Green's function for the electromagnetic field in the presence of a smooth- and a convex-surfaced perfectly electrically conductive obstacle.

Range Sensor-Based Efficient Obstacle Avoidance through Selective Decision-Making.

PubMed

Shim, Youngbo; Kim, Gon-Woo

2018-03-29

In this paper, we address a collision avoidance method for mobile robots. Many conventional obstacle avoidance methods have been focused solely on avoiding obstacles. However, this can cause instability when passing through a narrow passage, and can also generate zig-zag motions. We define two strategies for obstacle avoidance, known as Entry mode and Bypass mode. Entry mode is a pattern for passing through the gap between obstacles, while Bypass mode is a pattern for making a detour around obstacles safely. With these two modes, we propose an efficient obstacle avoidance method based on the Expanded Guide Circle (EGC) method with selective decision-making. The simulation and experiment results show the validity of the proposed method.

The importance of the concepts of disaster, catastrophe, violence, trauma and barbarism in defining posttraumatic stress disorder in clinical practice

PubMed Central

Braga, Luciana L; Fiks, Jose P; Mari, Jair J; Mello, Marcelo F

2008-01-01

Background Several terms in the scientific literature about posttraumatic stress disorder are used with different meanings in studies conducted by different authors. Words such as trauma, violence, catastrophe, disaster and barbarism are often used vaguely or confusingly, and their meanings change in different articles. The lack of conceptual references for these expressions complicates the organization of literature. Furthermore, the absence of clear concepts may be an obstacle to clinical treatment because the use of these words by the patients does not necessarily point to a diagnosis of posttraumatic stress disorder. Discussion A critical review of scientific literature showed that stress can be divided in stages to facilitate specific terminological adjustments to the event itself, to the subject-event interaction and to psychological responses. Moreover, it demonstrated that the varying concept of trauma expands into fundamental psychotherapeutic definitions and that the meanings of violence associated with barbarism are an obstacle to resilience. Therefore, this study updates the etymological origins and applications of these words, connects them to the expansions of meanings that can be operated in the clinical care of patients with posttraumatic stress disorder, and analyzes them critically according to the criterion A of DSM-IV and ICD-10. Summary The terminology in the literature about posttraumatic stress disorder includes a plethora of terms whose meanings are not fully understood, and that, therefore, limit this terminology. The analysis of these terms suggested that the transformation of the concept of trauma led to a broader understanding of this phenomenon in its psychic dimensions, that a barbarian type of violence constitutes an obstacle to resilience, and that the criterion A of the DSM-IV and ICD-10 shows imprecision and conceptual fragilities. Methods To develop this debate article, a current specialized literature review was achieved by searching and retrieving the key terms from two major databases: PubMed and PsycINFO. The key terms included "disaster", "catastrophe", "barbarism", "terrorism", "trauma", "psychic trauma" and "violence", also in combination with the terms "PTSD", "concept" and "conceptual aspects". The data were captured specially from review articles. The included studies were those mostly identified by the authors as relevant by the presence of a conceptual approach in any part of the paper. Researches that relied solely on empirical indicators, like psychopathological, neurobiological or pharmacological aspects, were excluded. The focus here was in conceptual aspects, even when some few empirical studies were included. As it was noted a paucity of medical references related to conceptual aspects of these terms, a wider literature needed to be included, including chapters, books and articles proceeded from the Humanities areas. "Interdisciplinary research is needed in this area to include perspectives from a range of different disciplines" once that "to promote public health (...) new dimensions of such interactions and the implications thereof should be pursued in collaboration with researchers from broader areas" [1]. PMID:18694520

The importance of the concepts of disaster, catastrophe, violence, trauma and barbarism in defining posttraumatic stress disorder in clinical practice.

PubMed

Braga, Luciana L; Fiks, Jose P; Mari, Jair J; Mello, Marcelo F

2008-08-12

Several terms in the scientific literature about posttraumatic stress disorder are used with different meanings in studies conducted by different authors. Words such as trauma, violence, catastrophe, disaster and barbarism are often used vaguely or confusingly, and their meanings change in different articles. The lack of conceptual references for these expressions complicates the organization of literature. Furthermore, the absence of clear concepts may be an obstacle to clinical treatment because the use of these words by the patients does not necessarily point to a diagnosis of posttraumatic stress disorder. A critical review of scientific literature showed that stress can be divided in stages to facilitate specific terminological adjustments to the event itself, to the subject-event interaction and to psychological responses. Moreover, it demonstrated that the varying concept of trauma expands into fundamental psychotherapeutic definitions and that the meanings of violence associated with barbarism are an obstacle to resilience. Therefore, this study updates the etymological origins and applications of these words, connects them to the expansions of meanings that can be operated in the clinical care of patients with posttraumatic stress disorder, and analyzes them critically according to the criterion A of DSM-IV and ICD-10. The terminology in the literature about posttraumatic stress disorder includes a plethora of terms whose meanings are not fully understood, and that, therefore, limit this terminology. The analysis of these terms suggested that the transformation of the concept of trauma led to a broader understanding of this phenomenon in its psychic dimensions, that a barbarian type of violence constitutes an obstacle to resilience, and that the criterion A of the DSM-IV and ICD-10 shows imprecision and conceptual fragilities. To develop this debate article, a current specialized literature review was achieved by searching and retrieving the key terms from two major databases: PubMed and PsycINFO. The key terms included "disaster", "catastrophe", "barbarism", "terrorism", "trauma", "psychic trauma" and "violence", also in combination with the terms "PTSD", "concept" and "conceptual aspects". The data were captured specially from review articles. The included studies were those mostly identified by the authors as relevant by the presence of a conceptual approach in any part of the paper. Researches that relied solely on empirical indicators, like psychopathological, neurobiological or pharmacological aspects, were excluded. The focus here was in conceptual aspects, even when some few empirical studies were included. As it was noted a paucity of medical references related to conceptual aspects of these terms, a wider literature needed to be included, including chapters, books and articles proceeded from the Humanities areas. "Interdisciplinary research is needed in this area to include perspectives from a range of different disciplines" once that "to promote public health (...) new dimensions of such interactions and the implications thereof should be pursued in collaboration with researchers from broader areas" 1.

Laminar CuO-water nano-fluid flow and heat transfer in a backward-facing step with and without obstacle

NASA Astrophysics Data System (ADS)

Togun, Hussein

2016-03-01

This paper presents a numerical investigate on CuO-water nano-fluid and heat transfer in a backward-facing step with and without obstacle. The range of Reynolds number varied from 75 to 225 with volume fraction on CuO nanoparticles varied from 1 to 4 % at constant heat flux was investigated. Continuity, momentum, and energy equations with finite volume method in two dimensions were employed. Four different configurations of backward-facing step (without obstacle, with obstacle of 1.5 mm, with obstacle of 3 mm, with obstacle of 4.5 mm) were considered to find the best thermal performance. The results show that the maximum augmentation in heat transfer was about 22 % for backward-facing step with obstacle of 4.5 mm and using CuO nanoparticles at Reynolds number of 225 compared with backward-facing step without obstacle. It is also observed that increase in size of recirculation region with increase of height obstacle on the channel wall has remarkable effect on thermal performance. The results also found that increases in Reynolds number, height obstacle, and volume fractions of CuO nanoparticles lead to increase of pressure drop.

A formal framework for scenario development in support of environmental decision-making

USGS Publications Warehouse

Mahmoud, M.; Liu, Yajing; Hartmann, H.; Stewart, S.; Wagener, T.; Semmens, D.; Stewart, R.; Gupta, H.; Dominguez, D.; Dominguez, F.; Hulse, D.; Letcher, R.; Rashleigh, Brenda; Smith, C.; Street, R.; Ticehurst, J.; Twery, M.; van, Delden H.; Waldick, R.; White, D.; Winter, L.

2009-01-01

Scenarios are possible future states of the world that represent alternative plausible conditions under different assumptions. Often, scenarios are developed in a context relevant to stakeholders involved in their applications since the evaluation of scenario outcomes and implications can enhance decision-making activities. This paper reviews the state-of-the-art of scenario development and proposes a formal approach to scenario development in environmental decision-making. The discussion of current issues in scenario studies includes advantages and obstacles in utilizing a formal scenario development framework, and the different forms of uncertainty inherent in scenario development, as well as how they should be treated. An appendix for common scenario terminology has been attached for clarity. Major recommendations for future research in this area include proper consideration of uncertainty in scenario studies in particular in relation to stakeholder relevant information, construction of scenarios that are more diverse in nature, and sharing of information and resources among the scenario development research community. ?? 2008 Elsevier Ltd.

Medical Readiness of the Reserve Component.

PubMed

Brauner, Marygail K; Jackson, Timothy; Gayton, Elizabeth

2012-01-01

The reserve components (RCs) of the U.S. military must ensure that reservists are not only properly equipped and trained, but also medically ready to serve. Medical readiness means that service members are free from health-related conditions, including dental conditions, that could limit their ability to carry out their duties. Medically ready reservists require less medical and dental support in theater and fewer medical evacuations from theater, both of which save money and free assets for other purposes. This article identifies existing medical readiness requirements, quantifies the current status of RC medical readiness, identifies obstacles to achieving compliance, and suggests options for improving medical readiness in a cost-effective manner. The authors find that time and expense are the major barriers to the RCs achieving their overall goals for medical readiness. Recommendations include standardizing medical readiness criteria across services, improving data reporting and archiving processes, providing incentives to individuals and units to achieve medical readiness, and continuing to extend TRICARE coverage to reservists prior to deployment.

Efficient and Highly Selective Solvent-Free Oxidation of Primary Alcohols to Aldehydes Using Bucky Nanodiamond.

PubMed

Lin, Yangming; Wu, Kuang-Hsu Tim; Yu, Linhui; Heumann, Saskia; Su, Dang Sheng

2017-09-11

Selective oxidation of alcohols to aldehydes is widely applicable to the synthesis of various green chemicals. The poor chemoselectivity for complicated primary aldehydes over state-of-the-art metal-free or metal-based catalysts represents a major obstacle for industrial application. Bucky nanodiamond is a potential green catalyst that exhibits excellent chemoselectivity and cycling stability for the selective oxidation of primary alcohols in diverse structures (22 examples, including aromatic, substituted aromatic, unsaturated, heterocyclic, and linear chain alcohols) to their corresponding aldehydes. The results are comparable to reported transition-metal catalysts including conventional Pt/C and Ru/C catalysts for certain substrates under solvent-free conditions. The possible activation process of the oxidant and substrates by the surface oxygen groups and defect species are revealed with model catalysts, ex situ electrochemical measurements, and ex situ attenuated total reflectance. The zigzag edges of sp 2 carbon planes are shown to play a key role in these reactions. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Review of the Italian current legislation on research biobanking activities on the eve of the participation of national biobanks’ network in the legal consortium BBMRI-ERIC.

PubMed

Calzolari, Alessia; Napolitano, Mariarosaria; Bravo, Elena

2013-04-01

The ethical-legal framework of research biobanking activities is still scarcely defined in Italy, and this constitutes a major obstacle to exploit the potential benefits of existing bioresource patrimony at the national and international levels. Biobanking and Biomolecular Resources Research Infrastructure (BBMRI), which aims to become a major interface between biological samples and data and top-level biological and medical research, is undertaking the crucial transformation to the ERIC (European Research Infrastructure Consortium) legal entity. In this scenario, there is a need to address the national legal and ethical concerns that are strictly correlated with the use of human biosources in research across European countries participating (and not) in BBMRI. In this perspective, this article aims to review the legal framework applying to research biobanking in Italy, including both "soft" nonbinding instruments and binding regulations. Since ethical and societal aspects impact biobanking research activities, the article discusses both the critical ethical and legal open issues that need to be implemented at the national level.

High-integrity databases for helicopter operations

NASA Astrophysics Data System (ADS)

Pschierer, Christian; Schiefele, Jens; Lüthy, Juerg

2009-05-01

Helicopter Emergency Medical Service missions (HEMS) impose a high workload on pilots due to short preparation time, operations in low level flight, and landings in unknown areas. The research project PILAS, a cooperation between Eurocopter, Diehl Avionics, DLR, EADS, Euro Telematik, ESG, Jeppesen, the Universities of Darmstadt and Munich, and funded by the German government, approached this problem by researching a pilot assistance system which supports the pilots during all phases of flight. The databases required for the specified helicopter missions include different types of topological and cultural data for graphical display on the SVS system, AMDB data for operations at airports and helipads, and navigation data for IFR segments. The most critical databases for the PILAS system however are highly accurate terrain and obstacle data. While RTCA DO-276 specifies high accuracies and integrities only for the areas around airports, HEMS helicopters typically operate outside of these controlled areas and thus require highly reliable terrain and obstacle data for their designated response areas. This data has been generated by a LIDAR scan of the specified test region. Obstacles have been extracted into a vector format. This paper includes a short overview of the complete PILAS system and then focus on the generation of the required high quality databases.

Noninvasive biosensor for hypoglycemia

NASA Astrophysics Data System (ADS)

Varadan, Vijay K.; Whitchurch, Ashwin K.; Sarukesi, Karunakaran

2003-01-01

Hypoglycemia-abnormal decrease in blood sugar- is a major obstacle in the management of diabetes and prevention of long-term complications, and it may impose serious effects on the brain, including impairment of memory and other cognitive functions. This is especially a concern in early childhood years when the nervous system is still developing. Hypoglycemic unawareness (in which the body"s normal ability to signal low blood sugar doesn"t work and an oncoming low blood sugar episode proceeds undetected) is a particularly frightening problem for many people with diabetes. Researchers have now uncovered evidence that repeated bouts of insulin-induced hypoglycemia can harm the brain over time, causing confusion, abnormal behavior, loss of consciousness, and seizures. Extreme cases have resulted in coma and death. In this paper, a non-invasive biosensor in a wrist watch along with a wireless data downloading system is proposed.

Training of trainers for community primary health care workers.

PubMed

Cernada, G P

1983-01-01

Training community-based health care workers in "developing" countries is essential to improving the quality of life in both rural and urban areas. Two major obstacles to such training are the tremendous social distance gap between these community workers and their more highly-educated and upper-class trainers (often medical officers) and the didactic, formal educational system. Bridging this gap demands a participant-centered, field-oriented approach which actively involves the trainee in the design, implementation and evaluation of the training program. A description of a philosophic learning approach based on self-initiated change, educational objectives related to planning, organizing, conducting and evaluating training, and specific learning methodologies utilizing participatory learning, non-formal educational techniques, field experience, continuing feedback and learner participation are reviewed. Included are: role playing, story telling, case studies, self-learning and simulation exercises, visuals, and Portapak videotape.

Emerging therapeutic targets in metastatic progression: a focus on breast cancer

PubMed Central

Li, Zhuo; Kang, Yibin

2016-01-01

Metastasis is the underlying cause of death for the majority of breast cancer patients. Despite significant advances in recent years in basic research and clinical development, therapies that specifically target metastatic breast cancer remain inadequate, and represents the single greatest obstacle to reducing mortality of late-stage breast cancer. Recent efforts have leveraged genomic analysis of breast cancer and molecular dissection of tumor-stromal cross-talk to uncover a number of promising candidates for targeted treatment of metastatic breast cancer. Rational combinations of therapeutic agents targeting tumor-intrinsic properties and microenvironmental components provide a promising strategy to develop precision treatments with higher specificity and less toxicity. In this review, we discuss the emerging therapeutic targets in breast cancer metastasis, from tumor-intrinsic pathways to those that involve the host tissue components, including the immune system. PMID:27000769

Can we overcome the effect of conflicts in rendering palliative care? An introduction to the Middle Eastern Cancer Consortium (MECC).

PubMed

Silbermann, Michael; Khleif, Amal; Tuncer, Murat; Pitsillides, Barbara; Shad, Aziza; Oberman, Amitai; Elshami, Mohammad; Gultekin, Murat; Daher, Michel; Tarawneh, Mohammed; Harford, Joe

2011-08-01

The Middle East has been experiencing an ongoing political conflict for the past several decades. This situation has been characterized by hostility often leading to violence of all sources. At times, such a conflict led to the outbreak of a military war, which was followed by an enmity between religious, ethnic, cultural, and national populations. In such environmental situations, palliative care professionals often confront major challenges including bias, mistrust, and mutual suspicion between patients and their treating clinicians. In order to overcome such obstacles, while rendering palliative care services, all professionals involved need careful planning and execution of their treatment plans. The latter is however possible, and sometimes successful even across lines of conflict, thereby promoting understanding, mutual respect, and tolerance between the involved communities and individuals.

Recent advances in microbial production of mannitol: utilization of low-cost substrates, strain development and regulation strategies.

PubMed

Zhang, Min; Gu, Lei; Cheng, Chao; Ma, Jiangfeng; Xin, Fengxue; Liu, Junli; Wu, Hao; Jiang, Min

2018-02-26

Mannitol has been widely used in fine chemicals, pharmaceutical industries, as well as functional foods due to its excellent characteristics, such as antioxidant protecting, regulation of osmotic pressure and non-metabolizable feature. Mannitol can be naturally produced by microorganisms. Compared with chemical manufacturing, microbial production of mannitol provides high yield and convenience in products separation; however the fermentative process has not been widely adopted yet. A major obstacle to microbial production of mannitol under industrial-scale lies in the low economical efficiency, owing to the high cost of fermentation medium, leakage of fructose, low mannitol productivity. In this review, recent advances in improving the economical efficiency of microbial production of mannitol were reviewed, including utilization of low-cost substrates, strain development for high mannitol yield and process regulation strategies for high productivity.

National Ignition Facility Project: An Update

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

Hogan, W J; Moses, E; Warner, B

2000-12-07

The National Ignition Facility (NIF) consists of 192 forty-centimeter-square laser beams and a 10-m-diameter target chamber. Physical construction began in 1997. The Laser and Target Area Building and the Optics Assembly Building were the first major construction activities, and despite several unforeseen obstacles, the buildings are now 92% complete and have been done on time and within cost. Prototype component development and testing has proceeded in parallel. Optics vendors have installed full-scale production lines and have done prototype production runs. The assembly and integration of the beampath infrastructure has been reconsidered and a new approach has been developed. This papermore » will discuss the status of the NIF project and the plans for completion. It will also include summary information on Laser MegaJoule (LMJ) provided by M. Andre, LMJ Project Director.« less

The National Ignition Facility Project: An Update

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

Hogan, W.J.; Moses, E.; Warner, B.

2000-12-07

The National Ignition Facility (NIT) consists of 192 forty-centimeter-square laser beams and a 10-m-diameter target chamber. Physical construction began in 1997. The Laser and Target Area Building and the Optics Assembly Building were the first major construction activities, and despite several unforeseen obstacles, the buildings are now 92% complete and have been done on time and within cost. Prototype component development and testing has proceeded in parallel. Optics vendors have installed full-scale production lines and have done prototype production runs. The assembly and integration of the beam path infrastructure has been reconsidered and a new approach has been developed. Thismore » paper will discuss the status of the NIF project and the plans for completion. It will also include summary information on Laser MegaJoule (LMJ) provided by M. Andre, LMJ Project Director.« less

Future of Treatment for Nonalcoholic Steatohepatitis: Can the Use of Safe, Evidence-Based, Clinically Proven Supplements Provide the Answer to the Unmet Need?

PubMed

Ilan, Yaron

2018-04-20

The epidemic of nonalcoholic fatty liver disease (NAFLD) has created a real and unmet therapeutic need. The long regulatory pathway and the focus on selected subsets of patients with established and advanced disease are some of the current obstacles to providing effective treatment for the majority of NAFLD patients. The complexity of the disease pathogenesis, which involves multiple mechanisms, requires targeting of more than one pathway or a combination-based therapy. Although the drugs being developed may prevent progression to cirrhosis or may decrease negative liver outcomes, their effects on cardiometabolic health and cancer prevention remain unknown. Providing expensive compounds to a large proportion of the population for long-term use would place an economic burden on health care providers. Thus, there is a missed opportunity for early intervention in the course of the disease, by providing agents that improve cardiometabolic status and the progression of fatty liver toward steatohepatitis. Several natural supplements have the potential to meet these needs. This review discusses some of the major obstacles to drug development for NASH treatment. Milestones in bringing evidenced-based, scientifically proven, patent-protected, clinically tested, safe compounds to patients with NAFLD or NASH within a relatively short period of time are presented. The regulatory, intellectual property, manufacturing, and clinical development steps, along with applicable timelines, are discussed. These compounds may provide a possible solution to the challenges associated with the treatment of the majority of patients.

The Analysis of Physics Learning in Senior High School of Semarang Based on The Scientific Approach and Assessment

NASA Astrophysics Data System (ADS)

Hardyanti, R. C.; Hartono; Fianti

2018-03-01

Physics Learning in Curriculum of 2013 is closely related to the implementation of scientific approach and authentic assessment in learning. This study aims to analyze the implementation of scientific approaches and authentic assessment in physics learning, as well as to analyze the constraints of scientific approach and authentic assessment in physics learning. The data collection techniques used in this study are questionnaires, observations, interviews, and documentation. The calculation results used are percentage techniques and analyzed by using qualitative descriptive approach. Based on the results of research and discussion, the implementation of physics learning based on the scientific approach goes well with the percentage of 84.60%. Physical learning activity based on authentic assessment also goes well with the percentage of 88%. The results of the percentage of scientific approaches and authentic assessment approaches are less than 100%. It shows that there are obstacles to the implementation of the scientific approach and the constraints of authentic assessment. The obstacles to the implementation of scientific approach include time, heavy load of material, input or ability of learners, the willingness of learners in asking questions, laboratory support, and the ability of students to process data. While the obstacles to the implementation of authentic assessment include the limited time for carrying out of authentic assessment, the components of the criteria in carrying out the authentic assessment, the lack of discipline in administering the administration, the difficulty of changing habits in carrying out the assessment from traditional assessment to the authentic assessment, the obstacle to process the score in accordance with the format Curriculum of 2013.

Spectrum Modal Analysis for the Detection of Low-Altitude Windshear with Airborne Doppler Radar

NASA Technical Reports Server (NTRS)

Kunkel, Matthew W.

1992-01-01

A major obstacle in the estimation of windspeed patterns associated with low-altitude windshear with an airborne pulsed Doppler radar system is the presence of strong levels of ground clutter which can strongly bias a windspeed estimate. Typical solutions attempt to remove the clutter energy from the return through clutter rejection filtering. Proposed is a method whereby both the weather and clutter modes present in a return spectrum can be identified to yield an unbiased estimate of the weather mode without the need for clutter rejection filtering. An attempt will be made to show that modeling through a second order extended Prony approach is sufficient for the identification of the weather mode. A pattern recognition approach to windspeed estimation from the identified modes is derived and applied to both simulated and actual flight data. Comparisons between windspeed estimates derived from modal analysis and the pulse-pair estimator are included as well as associated hazard factors. Also included is a computationally attractive method for estimating windspeeds directly from the coefficients of a second-order autoregressive model. Extensions and recommendations for further study are included.

Improvements in Obstacle Clearance Parameters and Reaction Time Over a Series of Obstacles Revealed After Five Repeated Testing Sessions in Older Adults.

PubMed

Jehu, Deborah A; Lajoie, Yves; Paquet, Nicole

2017-12-21

The purpose of this study was to investigate obstacle clearance and reaction time parameters when crossing a series of six obstacles in older adults. A second aim was to examine the repeated exposure of this testing protocol once per week for 5 weeks. In total, 10 older adults (five females; age: 67.0 ± 6.9 years) walked onto and over six obstacles of varying heights (range: 100-200 mm) while completing no reaction time, simple reaction time, and choice reaction time tasks once per week for 5 weeks. The highest obstacles elicited the lowest toe clearance, and the first three obstacles revealed smaller heel clearance compared with the last three obstacles. Dual tasking negatively impacted obstacle clearance parameters when information processing demands were high. Longer and less consistent time to completion was observed in Session 1 compared with Sessions 2-5. Finally, improvements in simple reaction time were displayed after Session 2, but choice reaction time gradually improved and did not reach a plateau after repeated testing.

Numerical investigation on layout optimization of obstacles in a three-dimensional passive micromixer.

PubMed

Chen, Xueye; Zhao, Zhongyi

2017-04-29

This paper aims at layout optimization design of obstacles in a three-dimensional T-type micromixer. Numerical analysis shows that the direction of flow velocity change constantly due to the obstacles blocking, which produces the chaotic convection and increases species mixing effectively. The orthogonal experiment method was applied for determining the effects of some key parameters on mixing efficiency. The weights in the order are: height of obstacles > geometric shape > symmetry = number of obstacles. Based on the optimized results, a multi-units obstacle micromixer was designed. Compared with T-type micromixer, the multi-units obstacle micromixer is more efficient, and more than 90% mixing efficiency were obtained for a wide range of peclet numbers. It can be demonstrated that the presented optimal design method of obstacles layout in three-dimensional microchannels is a simple and effective technology to improve species mixing in microfluidic devices. The obstacles layout methodology has the potential for applications in chemical engineering and bioengineering. Copyright © 2017 Elsevier B.V. All rights reserved.

Numerical approach of collision avoidance and optimal control on robotic manipulators

NASA Technical Reports Server (NTRS)

Wang, Jyhshing Jack

1990-01-01

Collision-free optimal motion and trajectory planning for robotic manipulators are solved by a method of sequential gradient restoration algorithm. Numerical examples of a two degree-of-freedom (DOF) robotic manipulator are demonstrated to show the excellence of the optimization technique and obstacle avoidance scheme. The obstacle is put on the midway, or even further inward on purpose, of the previous no-obstacle optimal trajectory. For the minimum-time purpose, the trajectory grazes by the obstacle and the minimum-time motion successfully avoids the obstacle. The minimum-time is longer for the obstacle avoidance cases than the one without obstacle. The obstacle avoidance scheme can deal with multiple obstacles in any ellipsoid forms by using artificial potential fields as penalty functions via distance functions. The method is promising in solving collision-free optimal control problems for robotics and can be applied to any DOF robotic manipulators with any performance indices and mobile robots as well. Since this method generates optimum solution based on Pontryagin Extremum Principle, rather than based on assumptions, the results provide a benchmark against which any optimization techniques can be measured.

[A semimicroquality evaluation method on Panax notoginseng and its application in analysis of continuous cropping obstacles research samples].

PubMed

Cao, Yi; Wang, Chao-Qun; Xu, Feng; Jia, Xiu-Hong; Liu, Guang-Xue; Yang, Sheng-Chao; Long, Guang-Qiang; Chen, Zhong-Jian; Wei, Fu-Zhou; Yang, Shao-Zhou; Fukuda, Kozo; Wang, Xuan; Cai, Shao-Qing

2016-10-01

Panax notoginseng is a commonly used traditional Chinese medicine with blood activating effect while has continuous cropping obstacle problem in planting process. In present study, a semimicroextraction method with water-saturated n-butanol on 0.1 g notoginseng sample was established with good repeatability (RSD<2.5%) and 9.6%-20.6% higher extraction efficiency of seven saponins than the conventional method. A total of 16 characteristic peaks were identified by LC-MS-IT-TOF, including eight 20(S)-protopanaxatriol (PPT) type saponins and eight 20(S)-protopanaxadiol (PPD) type saponins. The established method was utilized to evaluate the quality of notoginseng samples cultivated by manual intervened methods to overcome continuous cropping obstacles.As a result, HPLC fingerprint similarity, content of Fa and ratio of notoginsenoside K and notoginsenoside Fa (N-K/Fa) were found out to be as valuatable markers of the quality of samples in continuous cropping obstacle research, of which N-K/Fa could also be applied to the analysis of notoginseng samples with different growth years.Notoginseng samples with continuous cropping obstacle had HPLC fingerprint similarity lower than 0.87, in consistent with normal sample, and had significant lower content of notoginsenoside Fa and significant higher N-K/Fa (2.35-4.74) than normal group (0.45-1.33). All samples in the first group with manual intervention showed high similarity with normal group (>0.87), similar content of common peaks and N-K/Fa (0.42-2.06). The content of notoginsenoside K in the second group with manual intervention was higher than normal group. All samples except two displayed similarity higher than 0.87 and possessed content of 16 saponins close to normal group. The result showed that notoginseng samples with continuous cropping obstacle had lower quality than normal sample. And manual intervened methods could improve their quality in different levels.The method established in this study was simple, fast and accurate, and the markers may provide new guides for quality control in continuous cropping obstacle research of notoginseng. Copyright© by the Chinese Pharmaceutical Association.

Autonomous dynamic obstacle avoidance for bacteria-powered microrobots (BPMs) with modified vector field histogram

PubMed Central

Kim, Hoyeon; Cheang, U. Kei

2017-01-01

In order to broaden the use of microrobots in practical fields, autonomous control algorithms such as obstacle avoidance must be further developed. However, most previous studies of microrobots used manual motion control to navigate past tight spaces and obstacles while very few studies demonstrated the use of autonomous motion. In this paper, we demonstrated a dynamic obstacle avoidance algorithm for bacteria-powered microrobots (BPMs) using electric field in fluidic environments. A BPM consists of an artificial body, which is made of SU-8, and a high dense layer of harnessed bacteria. BPMs can be controlled using externally applied electric fields due to the electrokinetic property of bacteria. For developing dynamic obstacle avoidance for BPMs, a kinematic model of BPMs was utilized to prevent collision and a finite element model was used to characteristic the deformation of an electric field near the obstacle walls. In order to avoid fast moving obstacles, we modified our previously static obstacle avoidance approach using a modified vector field histogram (VFH) method. To validate the advanced algorithm in experiments, magnetically controlled moving obstacles were used to intercept the BPMs as the BPMs move from the initial position to final position. The algorithm was able to successfully guide the BPMs to reach their respective goal positions while avoiding the dynamic obstacles. PMID:29020016

Autonomous dynamic obstacle avoidance for bacteria-powered microrobots (BPMs) with modified vector field histogram.

PubMed

Kim, Hoyeon; Cheang, U Kei; Kim, Min Jun

2017-01-01

In order to broaden the use of microrobots in practical fields, autonomous control algorithms such as obstacle avoidance must be further developed. However, most previous studies of microrobots used manual motion control to navigate past tight spaces and obstacles while very few studies demonstrated the use of autonomous motion. In this paper, we demonstrated a dynamic obstacle avoidance algorithm for bacteria-powered microrobots (BPMs) using electric field in fluidic environments. A BPM consists of an artificial body, which is made of SU-8, and a high dense layer of harnessed bacteria. BPMs can be controlled using externally applied electric fields due to the electrokinetic property of bacteria. For developing dynamic obstacle avoidance for BPMs, a kinematic model of BPMs was utilized to prevent collision and a finite element model was used to characteristic the deformation of an electric field near the obstacle walls. In order to avoid fast moving obstacles, we modified our previously static obstacle avoidance approach using a modified vector field histogram (VFH) method. To validate the advanced algorithm in experiments, magnetically controlled moving obstacles were used to intercept the BPMs as the BPMs move from the initial position to final position. The algorithm was able to successfully guide the BPMs to reach their respective goal positions while avoiding the dynamic obstacles.

Residents' Perspectives on Careers in Academic Medicine: Obstacles and Opportunities.

PubMed

Lin, Steven; Nguyen, Cathina; Walters, Emily; Gordon, Paul

2018-03-01

Worsening faculty shortages in medical schools and residency programs are threatening the US medical education infrastructure. Little is known about the factors that influence the decision of family medicine residents to choose or not choose academic careers. Our study objective was to answer the following question among family medicine residents: "What is your greatest concern or fear about pursuing a career in academic family medicine?" Participants were family medicine residents who attended the Faculty for Tomorrow Workshop at the Society of Teachers of Family Medicine Annual Spring Conference in 2016 and 2017. Free responses to the aforementioned prompt were analyzed using a constant comparative method and grounded theory approach. A total of 156 participants registered for the workshops and 95 (61%) answered the free response question. Eight distinct themes emerged from the analysis. The most frequently recurring theme was "lack of readiness or mentorship," which accounted for nearly one-third (31%) of the codes. Other themes included work-life balance and burnout (17%), job availability and logistics (15%), lack of autonomy or flexibility (11%), competing pressures/roles (10%), lower financial rewards (4%), politics and bureaucracy (4%), and research (3%). To our knowledge, this is the first study to identify barriers and disincentives to pursuing a career in academic medicine from the perspective of family medicine residents. There may be at least eight major obstacles, for which we summarize and consider potential interventions. More research is needed to understand why residents choose, or don't choose, academic careers.

Implementation status of accrual accounting system in health sector.

PubMed

Mehrolhassani, Mohammad Hossien; Khayatzadeh-Mahani, Akram; Emami, Mozhgan

2014-07-29

Management of financial resources in health systems is one of the major issues of concern for policy makers globally. As a sub-set of financial management, accounting system is of paramount importance. In this paper, which presents part of the results of a wider research project on transition process from a cash accounting system to an accrual accounting system, we look at the impact of components of change on implementation of the new system. Implementing changes is fraught with many obstacles and surveying these challenges will help policy makers to better overcome them. The study applied a quantitative manner in 2012 at Kerman University of Medical Science in Iran. For the evaluation, a teacher made valid questionnaire with Likert scale was used (Cranach's alpha of 0.89) which included 7 change components in accounting system. The study population was 32 subordinate units of Kerman University of Medical Sciences and for data analysis, descriptive and inferential statistics and correlation coefficient in SPSS version 19 were used. Level of effect of all components on the implementation was average downward (5.06±1.86), except for the component "management & leadership (3.46±2.25)" (undesirable from external evaluators' viewpoint) and "technology (6.61±1.92) and work processes (6.35±2.19)" (middle to high from internal evaluators' viewpoint). Results showed that the establishment of accrual accounting system faces infrastructural challenges, especially the components of leadership and management and followers. As such, developing effective measures to overcome implementation obstacles should target these components.

Technology Transfer: A Third World Perspective.

ERIC Educational Resources Information Center

Akubue, Anthony I.

2002-01-01

Technology transfer models are based on assumptions that do not reflect Third-World realities. Obstacles to building indigenous technology capacity include multinational corporations' control of innovations, strings attached to foreign aid, and indigenous reluctance to undertake research. Four areas of development include foreign direct…

Challenges and opportunities in supporting sustainable agriculture and food security

USDA-ARS?s Scientific Manuscript database

The 2014 IUPAC International Congress of Pesticide Chemistry (San Francisco, August, 2014) included a symposium on “Challenges Associated with Global Adoption of Agricultural Biotechnology” to review current obstacles in promoting GM crops. Challenges identified by symposium presenters included i) ...

Women with doctorates in science: Perceptions of facilitative factors and obstacles to their success

NASA Astrophysics Data System (ADS)

Guimond, Pamela S.

In the past thirty years there has been a significant increase in the number of women pursuing careers in the biological sciences, yet similar increases have not been seen in the physical sciences or engineering. Research suggests that societal, educational, and personal factors may be the cause. This study was designed to validate factors previously identified as being influential on the learning of science by women, as well as to discover factors not previously identified and to gain an understanding of the degree to which each of these factors is perceived to relate to their academic success. Quantitative and qualitative methodologies were used to identify factors that facilitated the success of or presented obstacles to women as they pursued doctoral degrees in physical science and engineering. Sixty-four women scientists completed surveys. Of these, twelve participated in telephone interviews. The data collected from these methodologies, when taken together, allowed for both a generalizability of results and in-depth understanding of the factors identified. Three major themes were identified. First was the importance of people in these women's lives. Second was each woman's expression of personality traits including passion, determination, and resilience. Third was the importance of support from a variety of sources. All of the scientists considered support necessary for their success. Implications for practice include: providing girls with a wide variety of experiences in mathematics and science, including both in-school and out-of-school activities; providing girls with role models and mentors; utilizing a variety of teaching strategies aimed at girls' preferred learning styles; providing a variety of kinds of support girls need to feel welcome and valued; developing in girls personal characteristics associated with the culture of science; minimizing the use of high-stakes exams; and maximizing schedule flexibility so women can combine scientific careers and families.

The U.S. Needs International Cyber Treaties

DTIC Science & Technology

2010-03-01

formed to deal with issues surrounding cyber warfare . However, no major treaties between nations exist regarding this form of combat. Examining...the history of cyber warfare , the inadequate international response, the obstacles to international agreement, and poor U.S. readiness demonstrates...the current need for the U.S. to lead the effort to codify treaties. First, a brief history of cyber warfare helps to shed light on the international

Targeted Delivery of Therapeutic Oligonucleotides for the Treatment of Prostate Cancer

DTIC Science & Technology

2004-05-01

AD Award Number: DAMD17-01-1-0090 TITLE: Targeted Delivery of Therapeutic Oligonucleotides for the Treatment of Prostate Cancer PRINCIPAL...independence and chemoresistance are the major obstacles in the treatment of patients with advanced prostate cancer (Denis & Murphy, 1993; Oh & Kantoff...independence and chemoresistance in prostate cancer (McDonnell et al., 1992; Colombel et al., 1993; Berchem et al., 1995; Raffo et al., 1995; Bauer et al

Self-Determination and Goal Aspirations: African American and Latino Males' Perceptions of Their Persistence in Community College Basic and Transfer-Level Writing Courses

ERIC Educational Resources Information Center

Villarreal, María de Lourdes; García, Hugo A.

2016-01-01

This Grounded Theory study utilized Self-determination Theory to analyze the interview results of 18 community college African American and Latino males. The goal was to learn what helped participants to succeed and persist in developmental and transfer-level writing courses despite the obstacles that they faced. Three major themes emerged: (a)…

Performance Characterization of Obstacle Detection Algorithms for Aircraft Navigation

NASA Technical Reports Server (NTRS)

Kasturi, Rangachar; Camps, Octavia; Coraor, Lee; Gandhi, Tarak; Hartman, Kerry; Yang, Mau-Tsuen

2000-01-01

The research reported here is a part of NASA's Synthetic Vision System (SVS) project for the development of a High Speed Civil Transport Aircraft (HSCT). One of the components of the SVS is a module for detection of potential obstacles in the aircraft's flight path by analyzing the images captured by an on-board camera in real-time. Design of such a module includes the selection and characterization of robust, reliable, and fast techniques and their implementation for execution in real-time. This report describes the results of our research in realizing such a design.

Controlled motion in an elastic world. Research project: Manipulation strategies for massive space payloads

NASA Technical Reports Server (NTRS)

Book, Wayne J.

1992-01-01

The flexibility of the drives and structures of controlled motion systems are presented as an obstacle to be overcome in the design of high performance motion systems, particularly manipulator arms. The task and the measure of performance to be applied determine the technology appropriate to overcome this obstacle. Included in the technologies proposed are control algorithms (feedback and feed forward), passive damping enhancement, operational strategies, and structural design. Modeling of the distributed, nonlinear system is difficult, and alternative approaches are discussed. The author presents personal perspectives on the history, status, and future directions in this area.

When an object appears unexpectedly: anticipatory movement and object circumvention in individuals with and without Developmental Coordination Disorder.

PubMed

Wilmut, K; Barnett, A L

2017-05-01

Obstacles often appear unexpectedly in our pathway and these require us to make adjustments to avoid collision. Previous research has demonstrated that healthy adults will make anticipatory adjustments to gait where they have been told there is the possibility of an obstacle appearing. One population that may find this type of anticipatory movement difficult is individuals with Developmental Coordination Disorder (DCD). The current study considered how individuals with and without DCD adjust to the possibility of an obstacle appearing which would require circumvention. Fortyfour individuals with DCD and 44 age-matched controls (aged from 7 to 34 years of age) walked down an 11 m walkway under three conditions. Initially they were told this was a clear pathway and nothing in the environment would change (1, no possibility of an obstacle, no obstacle). They then performed a series of trials in which a gate may (2, possibility of an obstacle, obstacle) or may not (3, possibility of an obstacle, no obstacle) partially obstruct their pathway. We found that all participants increased medio-lateral trunk acceleration when there was the possibility of an obstacle but before the obstacle appeared, in addition the typical adults and older children also increased step width. When describing circumvention we found that the younger children showed an increase in trunk velocity and acceleration in all three directions compared to older children and adults. We also found that the individuals with DCD adjusted their path sooner and deviated more than their peers. The degree of adjustment to step width in anticipation of an obstacle was related to later medio-lateral velocity and timing of the deviation. Therefore, the lack of 'readying' the system where there is the possibility of an obstacle appearing seen in the individuals with DCD and the younger typical children may explain the increased medio-lateral velocity seen during circumvention.

A novel artificial immune algorithm for spatial clustering with obstacle constraint and its applications.

PubMed

Sun, Liping; Luo, Yonglong; Ding, Xintao; Zhang, Ji

2014-01-01

An important component of a spatial clustering algorithm is the distance measure between sample points in object space. In this paper, the traditional Euclidean distance measure is replaced with innovative obstacle distance measure for spatial clustering under obstacle constraints. Firstly, we present a path searching algorithm to approximate the obstacle distance between two points for dealing with obstacles and facilitators. Taking obstacle distance as similarity metric, we subsequently propose the artificial immune clustering with obstacle entity (AICOE) algorithm for clustering spatial point data in the presence of obstacles and facilitators. Finally, the paper presents a comparative analysis of AICOE algorithm and the classical clustering algorithms. Our clustering model based on artificial immune system is also applied to the case of public facility location problem in order to establish the practical applicability of our approach. By using the clone selection principle and updating the cluster centers based on the elite antibodies, the AICOE algorithm is able to achieve the global optimum and better clustering effect.

A stereo vision-based obstacle detection system in vehicles

NASA Astrophysics Data System (ADS)

Huh, Kunsoo; Park, Jaehak; Hwang, Junyeon; Hong, Daegun

2008-02-01

Obstacle detection is a crucial issue for driver assistance systems as well as for autonomous vehicle guidance function and it has to be performed with high reliability to avoid any potential collision with the front vehicle. The vision-based obstacle detection systems are regarded promising for this purpose because they require little infrastructure on a highway. However, the feasibility of these systems in passenger car requires accurate and robust sensing performance. In this paper, an obstacle detection system using stereo vision sensors is developed. This system utilizes feature matching, epipoplar constraint and feature aggregation in order to robustly detect the initial corresponding pairs. After the initial detection, the system executes the tracking algorithm for the obstacles. The proposed system can detect a front obstacle, a leading vehicle and a vehicle cutting into the lane. Then, the position parameters of the obstacles and leading vehicles can be obtained. The proposed obstacle detection system is implemented on a passenger car and its performance is verified experimentally.

Novel approaches to helicopter obstacle warning

NASA Astrophysics Data System (ADS)

Seidel, Christian; Samuelis, Christian; Wegner, Matthias; Münsterer, Thomas; Rumpf, Thomas; Schwartz, Ingo

2006-05-01

EADS Germany is the world market leader in commercial Helicopter Laser Radar (HELLAS) Obstacle Warning Systems. The HELLAS-Warning System has been introduced into the market in 2000, is in service at German Border Control (Bundespolizei) and Royal Thai Airforce and is successfully evaluated by the Foreign Comparative Test Program (FCT) of the USSOCOM. Currently the successor system HELLAS-Awareness is in development. It will have extended sensor performance, enhanced realtime data processing capabilities and advanced HMI features. We will give an outline of the new sensor unit concerning detection technology and helicopter integration aspects. The system provides a widespread field of view with additional dynamic line of sight steering and a large detection range in combination with a high frame rate of 3Hz. The workflow of the data processing will be presented with focus on novel filter techniques and obstacle classification methods. As commonly known the former are indispensable due to unavoidable statistical measuring errors and solarisation. The amount of information in the filtered raw data is further reduced by ground segmentation. The remaining raised objects are extracted and classified in several stages into different obstacle classes. We will show the prioritization function which orders the obstacles concerning to their threat potential to the helicopter taking into account the actual flight dynamics. The priority of an object determines the display and provision of warnings to the pilot. Possible HMI representation includes video or FLIR overlay on multifunction displays, audio warnings and visualization of information on helmet mounted displays and digital maps. Different concepts will be presented.

Green Commuting in the Health Care Sector: Obstacles and Best Practices.

PubMed

Kaplan, Susan; Ai, Ning; Orris, Peter; Sriraj, P S

2016-02-01

Fossil fuel transportation by health care providers contributes to the prevalence of diseases they treat. We conducted an exploratory study to understand obstacles to, and best practices for, greener commuting among health care providers. We surveyed staff of three hospital clinics as to how they commute and why, and interviewed key staff of five hospital leaders in green commuting about their programs. Factors that might change respondents' commuting choices from driving alone included financial incentives, convenience, and solutions to crime and safety concerns. Successful green commuting programs offer benefits including free or reduced transit passes, shuttle buses to transit stations, and free emergency rides home. Exemplary programs throughout the country demonstrate that modifying those factors within reach can impact the amount of fossil fuel energy used for health care provider transportation.

The birth of numerical weather prediction

NASA Astrophysics Data System (ADS)

Wiin-Nielsen, A.

1991-08-01

The paper describes the major events leading gradually to operational, numerical, short-range predictions for the large-scale atmospheric flow. The theoretical foundation starting with Rossby's studies of the linearized, barotropic equation and ending a decade and a half later with the general formulation of the quasi-geostrophic, baroclinic model by Charney and Phillips is described. The problems connected with the very long waves and the inconsistences of the geostrophic approximation which were major obstacles in the first experimental forecasts are discussed. The resulting changes to divergent barotropic and baroclinic models and to the use of the balance equation are described. After the discussion of the theoretical foundation, the paper describes the major developments leading to the Meteorology Project at the Institute for Advanced Studied under the leadership of John von Neumann and Jule Charney followed by the establishment of the Joint Numerical Weather Prediction Unit in Suitland, Maryland. The interconnected developments in Europe, taking place more-or-less at the same time, are described by concentrating on the activities in Stockholm where the barotropic model was used in many experiments leading also to operational forecasts. The further developments resulting in the use of the primitive equations and the formulation of medium-range forecasting models are not included in the paper.

The birth of numerical weather prediction

NASA Astrophysics Data System (ADS)

Wiin-Nielsen, A.

1991-09-01

The paper describes the major events leading gradually to operational, numerical, short-range predictions for the large-scale atmospheric flow. The theoretical foundation starting with Rossby's studies of the linearized, barotropic equation and ending a decade and a half later with the general formulation of the quasi-geostrophic, baroclinic model by Charney and Phillips is described. The problems connected with the very long waves and the inconsistences of the geostrophic approximation which were major obstacles in the first experimental forecasts are discussed. The resulting changes to divergent barotropic and baroclinic models and to the use of the balance equation are described. After the discussion of the theoretical foundation, the paper describes the major developments leading to the Meteorology Project at the Institute for Advanced Studied under the leadership of John von Neumann and Jule Charney followed by the establishment of the Joint Numerical Weather Prediction Unit in Suitland, Maryland. The inter-connected developments in Europe, taking place more-or-less at the same time, are described by concentrating on the activities in Stockholm where the barotropic model was used in many experiments leading also to operational forecasts. The further developments resulting in the use of the primitive equations and the formulation of medium-range forecasting models are not included in the paper.

Bridging the Divide between Neuroprosthetic Design, Tissue Engineering and Neurobiology

PubMed Central

Leach, Jennie B.; Achyuta, Anil Kumar H.; Murthy, Shashi K.

2009-01-01

Neuroprosthetic devices have made a major impact in the treatment of a variety of disorders such as paralysis and stroke. However, a major impediment in the advancement of this technology is the challenge of maintaining device performance during chronic implantation (months to years) due to complex intrinsic host responses such as gliosis or glial scarring. The objective of this review is to bring together research communities in neurobiology, tissue engineering, and neuroprosthetics to address the major obstacles encountered in the translation of neuroprosthetics technology into long-term clinical use. This article draws connections between specific challenges faced by current neuroprosthetics technology and recent advances in the areas of nerve tissue engineering and neurobiology. Within the context of the device–nervous system interface and central nervous system implants, areas of synergistic opportunity are discussed, including platforms to present cells with multiple cues, controlled delivery of bioactive factors, three-dimensional constructs and in vitro models of gliosis and brain injury, nerve regeneration strategies, and neural stem/progenitor cell biology. Finally, recent insights gained from the fields of developmental neurobiology and cancer biology are discussed as examples of exciting new biological knowledge that may provide fresh inspiration toward novel technologies to address the complexities associated with long-term neuroprosthetic device performance. PMID:20161810

Evolution of information-driven HIV/AIDS policies in China.

PubMed

Sun, Xinhua; Lu, Fan; Wu, Zunyou; Poundstone, Katharine; Zeng, Gang; Xu, Peng; Zhang, Dapeng; Liu, Kangmai; Liau, Adrian

2010-12-01

As China continues to commit to universal access to HIV/AIDS prevention, treatment and care services, its HIV/AIDS policies have become increasingly information driven. We review China's key national-level HIV/AIDS policies and discuss policy gaps and challenges ahead. We conducted a desk review of key national-level policies that have had a major impact on China's HIV/AIDS epidemic, and examined recent epidemiological data relevant to China's HIV response. National-level policies that have had a major impact on China's HIV/AIDS response include: 'Four Frees and One Care'; 5-year action plans; and HIV/AIDS regulation. These landmark policies have facilitated massive scaling up of services over the past decade. For example, the number of drug users provided with methadone maintenance treatment significantly increased from 8116 in 2005 to 241 975 in 2009; almost a 30-fold increase. The 'Four Frees and One Care' policy has increased the number of people living with AIDS on anti-retroviral treatment from some 100 patients in 2003 to over 80 000 in 2009. However, stigma and discrimination remains major obstacles for people living with HIV/AIDS trying to access services. China's current national policies are increasingly information driven and responsive to changes in the epidemic. However, gaps remain in policy implementation, and new policies are needed to meet emerging challenges.

Obstacle Avoidance On Roadways Using Range Data

NASA Astrophysics Data System (ADS)

Dunlay, R. Terry; Morgenthaler, David G.

1987-02-01

This report describes range data based obstacle avoidance techniques developed for use on an autonomous road-following robot vehicle. The purpose of these techniques is to detect and locate obstacles present in a road environment for navigation of a robot vehicle equipped with an active laser-based range sensor. Techniques are presented for obstacle detection, obstacle location, and coordinate transformations needed in the construction of Scene Models (symbolic structures representing the 3-D obstacle boundaries used by the vehicle's Navigator for path planning). These techniques have been successfully tested on an outdoor robotic vehicle, the Autonomous Land Vehicle (ALV), at speeds up to 3.5 km/hour.

Stepping over obstacles: anticipatory modifications in children with and without Down syndrome.

PubMed

Virji-Babul, Naznin; Brown, Michelle

2004-12-01

The purpose of this study was to explore the mechanism of anticipatory control of gait in relation to the perception of an obstacle. Typically developing (TD) children (4-7 years of age) and children with Down syndrome (5-6 years of age) walked and stepped over obstacles of two different heights-a "subtle" obstacle that was placed at a very low distance from the floor (1% of total body height) and an "obvious" obstacle that was placed at a much higher distance from the floor (15% of total body height). Spatial and temporal measures of the gait cycle were analyzed. TD children showed increased variability in pre-obstacle step lengths only in response to the higher obstacle. Children with DS showed a decrease in variability in response to the higher obstacle and marked qualitative changes in their gait cycle. Both groups of children were able to scale toe clearance with obstacle height. These results show that TD young children can make task-specific anticipatory adjustments by modulating step length and toe clearance. Children with DS show appropriate scaling of toe clearance and are beginning to show the emergence of anticipatory responses under specific environmental conditions.

Dynamic Obstacle Avoidance for Unmanned Underwater Vehicles Based on an Improved Velocity Obstacle Method

PubMed Central

Zhang, Wei; Wei, Shilin; Teng, Yanbin; Zhang, Jianku; Wang, Xiufang; Yan, Zheping

2017-01-01

In view of a dynamic obstacle environment with motion uncertainty, we present a dynamic collision avoidance method based on the collision risk assessment and improved velocity obstacle method. First, through the fusion optimization of forward-looking sonar data, the redundancy of the data is reduced and the position, size and velocity information of the obstacles are obtained, which can provide an accurate decision-making basis for next-step collision avoidance. Second, according to minimum meeting time and the minimum distance between the obstacle and unmanned underwater vehicle (UUV), this paper establishes the collision risk assessment model, and screens key obstacles to avoid collision. Finally, the optimization objective function is established based on the improved velocity obstacle method, and a UUV motion characteristic is used to calculate the reachable velocity sets. The optimal collision speed of UUV is searched in velocity space. The corresponding heading and speed commands are calculated, and outputted to the motion control module. The above is the complete dynamic obstacle avoidance process. The simulation results show that the proposed method can obtain a better collision avoidance effect in the dynamic environment, and has good adaptability to the unknown dynamic environment. PMID:29186878

Effects of overweight and obese body mass on motor planning and motor skills during obstacle crossing in children.

PubMed

Gill, Simone V; Hung, Ya-Ching

2014-01-01

Little is known about how obesity relates to motor planning and skills during functional tasks. We collected 3-D kinematics and kinetics as normal weight (n=10) and overweight/obese (n=12) children walked on flat ground and as they crossed low, medium, and high obstacles. We investigated if motor planning and motor skill impairments were evident during obstacle crossing. Baseline conditions showed no group differences (all ps>.05). Increased toe clearance was found on low obstacles (p=.01) for the overweight/obese group and on high obstacles (p=.01) for the normal weight group. With the crossing leg, the overweight/obese group had larger hip abduction angles (p=.01) and medial ground reaction forces (p=.006) on high obstacles and high anterior ground reaction forces on low obstacles (p=.001). With the trailing leg, overweight/obese children had higher vertical ground reaction forces on high obstacles (p=.005) and higher knee angles (p=.01) and anterior acceleration in the center of mass (p=.01) on low obstacles. These findings suggest that differences in motor planning and skills in overweight/obese children may be more apparent during functional activities. Copyright © 2013 Elsevier Ltd. All rights reserved.

Shock interaction behind a pair of cylindrical obstacles

NASA Astrophysics Data System (ADS)

Liu, Heng; Mazumdar, Raoul; Eliasson, Veronica

2014-11-01

The body of work focuses on two-dimensional numerical simulations of shock interaction with a pair of cylindrical obstacles, varying the obstacle separation and incident shock strength. With the shock waves propagating parallel to the center-line between the two cylindrical obstacles, the shock strengths simulated vary from a Mach of 1.4 to a Mach of 2.4, against a wide range of obstacle separation distance to their diameters. These cases are simulated via a software package called Overture, which is used to solve the inviscid Euler equations of gas dynamics on overlapping grids with adaptive mesh refinement. The goal of these cases is to find a so-called ``safe'' region for obstacle spacing and varying shock Mach numbers, such that the pressure in the ``safe'' region is reduced downstream of the obstacles. The benefits apply to both building and armor design for the purpose of shock wave mitigation to keep humans and equipment safe. The results obtained from the simulations confirm that the length of the ``safe'' region and the degree of shock wave attenuation depend on the ratio of obstacle separation distance to obstacle diameter. The influence of various Mach number is also discussed.

Self-bending elastic waves and obstacle circumventing in wireless power transfer

NASA Astrophysics Data System (ADS)

Tol, S.; Xia, Y.; Ruzzene, M.; Erturk, A.

2017-04-01

We demonstrate self-bending of elastic waves along convex trajectories by means of geometric and phased arrays. Potential applications include ultrasonic imaging and manipulation, wave focusing, and wireless power transfer around obstacles. The basic concept is illustrated through a geometric array, which is designed to implement a phase delay profile among the array elements that leads to self-bending along a specified circular trajectory. Experimental validation is conducted for the lowest asymmetric Lamb wave mode in a thin plate over a range of frequencies to investigate the bandwidth of the approach. Experiments also illustrate the functionality of the array as a transmitter to deliver elastic wave energy to a receiver/harvester located behind a large obstacle for electrical power extraction. It is shown that the trajectory is not distorted by the presence of the obstacle and circumventing is achieved. A linear phased array counterpart of the geometric array is then constructed to illustrate the concept by imposing proper time delays to the array elements, which allows the generation of different trajectories using the same line source. This capability is demonstrated by tailoring the path diameter in the phased array setting, which offers the flexibility and versatility to induce a variety of convex trajectories for self-bending elastic waves.

Feeling the force: how pollen tubes deal with obstacles.

PubMed

Burri, Jan T; Vogler, Hannes; Läubli, Nino F; Hu, Chengzhi; Grossniklaus, Ueli; Nelson, Bradley J

2018-06-15

Physical forces are involved in the regulation of plant development and morphogenesis by translating mechanical stress into the modification of physiological processes, which, in turn, can affect cellular growth. Pollen tubes respond rapidly to external stimuli and provide an ideal system to study the effect of mechanical cues at the single-cell level. Here, pollen tubes were exposed to mechanical stress while monitoring the reconfiguration of their growth and recording the generated forces in real-time. We combined a lab-on-a-chip device with a microelectromechanical systems (MEMS)-based capacitive force sensor to mimic and quantify the forces that are involved in pollen tube navigation upon confronting mechanical obstacles. Several stages of obstacle avoidance were identified, including force perception, growth adjustment and penetration. We have experimentally determined the perceptive force threshold, which is the force threshold at which the pollen tube reacts to an obstacle, for Lilium longiflorum and Arabidopsis thaliana. In addition, the method we developed provides a way to calculate turgor pressure based on force and optical data. Pollen tubes sense physical barriers and actively adjust their growth behavior to overcome them. Furthermore, our system offers an ideal platform to investigate intracellular activity during force perception and growth adaption in tip growing cells. © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.

Saying "no" to temptation: Want-to motivation improves self-regulation by reducing temptation rather than by increasing self-control.

PubMed

Milyavskaya, Marina; Inzlicht, Michael; Hope, Nora; Koestner, Richard

2015-10-01

Self-regulation has been conceptualized as the interplay between controlled and impulsive processes; however, most research has focused on the controlled side (i.e., effortful self-control). The present studies focus on the effects of motivation on impulsive processes, including automatic preferences for goal-disruptive stimuli and subjective reports of temptations and obstacles, contrasting them with effects on controlled processes. This is done by examining people's implicit affective reactions in the face of goal-disruptive "temptations" (Studies 1 and 2), subjective reports of obstacles (Studies 2 and 3) and expended effort (Study 3), as well as experiences of desires and self-control in real-time using experience sampling (Study 4). Across these multiple methods, results show that want-to motivation results in decreased impulsive attraction to goal-disruptive temptations and is related to encountering fewer obstacles in the process of goal pursuit. This, in turn, explains why want-to goals are more likely to be attained. Have-to motivation, on the other hand, was unrelated to people's automatic reactions to temptation cues but related to greater subjective perceptions of obstacles and tempting desires. The discussion focuses on the implications of these findings for self-regulation and motivation. (c) 2015 APA, all rights reserved).

Anomalous diffusion due to hindering by mobile obstacles undergoing Brownian motion or Orstein-Ulhenbeck processes.

PubMed

Berry, Hugues; Chaté, Hugues

2014-02-01

In vivo measurements of the passive movements of biomolecules or vesicles in cells consistently report "anomalous diffusion," where mean-squared displacements scale as a power law of time with exponent α<1 (subdiffusion). While the detailed mechanisms causing such behaviors are not always elucidated, movement hindrance by obstacles is often invoked. However, our understanding of how hindered diffusion leads to subdiffusion is based on diffusion amidst randomly located immobile obstacles. Here, we have used Monte Carlo simulations to investigate transient subdiffusion due to mobile obstacles with various modes of mobility. Our simulations confirm that the anomalous regimes rapidly disappear when the obstacles move by Brownian motion. By contrast, mobile obstacles with more confined displacements, e.g., Orstein-Ulhenbeck motion, are shown to preserve subdiffusive regimes. The mean-squared displacement of tracked protein displays convincing power laws with anomalous exponent α that varies with the density of Orstein-Ulhenbeck (OU) obstacles or the relaxation time scale of the OU process. In particular, some of the values we observed are significantly below the universal value predicted for immobile obstacles in two dimensions. Therefore, our results show that subdiffusion due to mobile obstacles with OU type of motion may account for the large variation range exhibited by experimental measurements in living cells and may explain that some experimental estimates are below the universal value predicted for immobile obstacles.

[Development of child mental health services in Lithuania: achievements and obstacles].

PubMed

Pūras, Dainius

2002-01-01

In 1990, political, economic and social changes in Lithuania introduced the possibility to develop for the first time in nations's history an effective and modern system of child mental health services. During the period between 1990 and 1995 a new model of services was developed in the Department of Social pediatrics and child psychiatry of Vilnius University. The model included development of child and adolescent psychiatric services, as well as early intervention services for infants and preschool children with developmental disabilities. The emphasis, following recommendations of WHO and existing international standards, was made on deinstitutionalization and development of family-oriented and community-based services, which have been ignored by previous system. In the first half of 90's of 20th century, new training programs for professionals were introduced, more than 50 methods of assessment, treatment and rehabilitation, new for Lithuanian clinical practice, were implemented, and a new model of services, including primary, secondary and tertiary level of prevention, was introduced in demonstration sites. However, during next phase of development, in 1997-2001, serious obstacles for replicating new approaches across the country, have been identified, which threatened successful implementation of the new model of services into everyday clinical practice. Analysis of obstacles, which are blocking development of new approaches in the field of child mental health, is presented in the article. The main obstacles, identified during analysis of socioeconomic context, planning and utilization of resources, running of the system of services and evaluation of outcomes, are as follows: lack of intersectorial cooperation between health, education and social welfare systems; strong tradition of discrimination of psychosocial interventions in funding schemes of health services; societal attitudes, which tend to discriminate and stigmatize marginal groups, including disabled children and dysfunctional families; lack of evidence-based decision making in the process of health care reform and reform of social infrastructure.

INL Autonomous Navigation System

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

2005-03-30

The INL Autonomous Navigation System provides instructions for autonomously navigating a robot. The system permits high-speed autonomous navigation including obstacle avoidance, waypoing navigation and path planning in both indoor and outdoor environments.

Development Administration: Obstacles, Theories and Implications for Planning. IIEP Occasional Papers No. 2.

ERIC Educational Resources Information Center

Rodman, Peter W.

In developing countries, public administration is hampered by a number of obstacles foreign to large industrialized nations. Some of these obstacles are shortages of tools and skilled personnel, outmoded organizational structures, political competition, and cultural and attitudinal barriers. The administrative obstacles and their…

Role of Educational Strategies for Human Resources in Green Infrastructure Operation and Maintenance

NASA Astrophysics Data System (ADS)

Ebrahimi, G.; Thurm, B.; Öberg, G.

2014-12-01

Rainwater harvesting and water reuse are receiving increasing attention as they hold the potential to effectively improve water conservation efforts. While many technical solutions have been developed, alternative water systems in built environments face significant challenges in the implementation and operational phases. The aim of this study is to examine obstacles to the implementation of alternative water systems in practice and identify criteria of feasible and sustainable solutions that allow bypassing of the identified obstacles. Interviews were conducted with planners, system designers and operators to find out which factors that central actors believe influence successful implementation of such systems. The results were analyzed in light of the literature. The actual performance of the water harvesting and reuse systems in four recently built green buildings in the Province of British Columbia, Canada was analyzed in light of the predicted outcome, according to the criteria identified in the interviews. It was found that the major obstacle to success is that the practical challenges involved in the implementation of alternative systems are underestimated. This, for example, leads to that education strategies for operational staff are not developed, and the staff is left floundering. This study highlights the importance of recognizing the need for strategic and directed educational programs for the human resources who are involved in operating and maintaining rainwater harvesting and water reuse systems.

Restricted ADP movement in cardiomyocytes: Cytosolic diffusion obstacles are complemented with a small number of open mitochondrial voltage-dependent anion channels.

PubMed

Simson, Päivo; Jepihhina, Natalja; Laasmaa, Martin; Peterson, Pearu; Birkedal, Rikke; Vendelin, Marko

2016-08-01

Adequate intracellular energy transfer is crucial for proper cardiac function. In energy starved failing hearts, partial restoration of energy transfer can rescue mechanical performance. There are two types of diffusion obstacles that interfere with energy transfer from mitochondria to ATPases: mitochondrial outer membrane (MOM) with voltage-dependent anion channel (VDAC) permeable to small hydrophilic molecules and cytoplasmatic diffusion barriers grouping ATP-producers and -consumers. So far, there is no method developed to clearly distinguish the contributions of cytoplasmatic barriers and MOM to the overall diffusion restriction. Furthermore, the number of open VDACs in vivo remains unknown. The aim of this work was to establish the partitioning of intracellular diffusion obstacles in cardiomyocytes. We studied the response of mitochondrial oxidative phosphorylation of permeabilized rat cardiomyocytes to changes in extracellular ADP by recording 3D image stacks of NADH autofluorescence. Using cell-specific mathematical models, we determined the permeability of MOM and cytoplasmatic barriers. We found that only ~2% of VDACs are accessible to cytosolic ADP and cytoplasmatic diffusion barriers reduce the apparent diffusion coefficient by 6-10×. In cardiomyocytes, diffusion barriers in the cytoplasm and by the MOM restrict ADP/ATP diffusion to similar extents suggesting a major role of both barriers in energy transfer and other intracellular processes. Copyright © 2016 Elsevier Ltd. All rights reserved.

eHealth in cardiovascular medicine: A clinical update.

PubMed

Saner, Hugo; van der Velde, Enno

2016-10-01

Demographic changes, progress in medicine technology and regional problems in providing healthcare to low density populations are posing great challenges to our healthcare systems. Rapid progress in computer sciences and information technologies have a great impact on the way healthcare will be delivered in the near future. This article describes opportunities and challenges of eHealth and telemedicine in the framework of our health systems and, in particular, in the context of today's cardiology services. The most promising applications of eHealth and telemedicine include: (a) prevention and lifestyle interventions; (b) chronic disease management including hypertension, diabetes and heart failure; (c) arrhythmia detection including early detection of atrial fibrillation and telemonitoring of devices such as pacemaker, internal cardioverter defibrillators and implantable rhythm monitoring devices; (d) telerehabilitation. Major obstacles to the integration of eHealth and telemedicine into daily clinical practice include limited large-scale evidence, in particular, for cost-effectiveness, as well as lack of interoperability, inadequate or fragmented legal frameworks and lack of reimbursement. An important challenge for those involved in these new technologies will be to keep the main focus on patient's individual needs and to carefully evaluate the evidence behind the practice. © The European Society of Cardiology 2016.

Bedside resuscitation of newborns with an intact umbilical cord: Experiences of midwives from British Columbia.

PubMed

Fulton, Colleen; Stoll, Kathrin; Thordarson, Dana

2016-03-01

level 1 evidence supports the practice of delayed cord clamping, and many doctors and midwives consider it routine care when delivering vigorous, term neonates. However, scarce research exists regarding the risks or benefits of delayed cord clamping for infants needing resuscitation with positive pressure ventilation. Nonetheless, some midwives in British Columbia already practice intact cord resuscitation (ICR) at planned home births and in the hospital in order to facilitate delayed cord clamping for infants who need resuscitation. we distributed an online survey to all registered midwives in British Columbia through the Midwives Association of BC between October 22nd and November 13th, 2014. This survey examined how midwives balance a commitment to delayed cord clamping with the need for resuscitation in home and hospital settings. a total of 82 midwives responded to the survey (response rate=35%). Many have practiced ICR (56, 69%). However, the majority (42, 78%) of respondents had only performed this type of resuscitation at planned home births and not in the hospital setting. In both settings, midwives found the ergonomics of resuscitation with an intact cord challenging, but cited a smoother physiologic transition for neonates as their primary reasons for this practice, despite the obstacles. Midwives reported a greater ability to use their delivery equipment to provide stable thermoregulation at the bedside at planned home births during a resuscitation compared with the set up of hospital delivery rooms. although the majority of participants practice ICR at planned home births, very few use this practice in the hospital setting. In the home, ergonomics is the primary obstacle for easily practicing ICR; hospital culture, protocols and lack of training are additional barriers to this practice in the hospital setting. Ergonomics and lack of appropriate set up in the delivery room were also primary obstacles. Midwives expressed a desire to find ways to incorporate ICR into the hospital setting. Copyright © 2016 Elsevier Ltd. All rights reserved.

From dictatorship to a reluctant democracy: stroke therapists talking about self-management

PubMed Central

Kilbride, Cherry

2014-01-01

Purpose Self-management is being increasingly promoted within chronic conditions including stroke. Concerns have been raised regarding professional ownership of some programmes, yet little is known of the professional’s experience. This paper aims to present the views of trained therapists about the utility of a specific self-management approach in stroke rehabilitation. Method Eleven stroke therapists trained in the self-management approach participated in semi-structured interviews. These were audio recorded, transcribed verbatim and analysed thematically. Results Two overriding themes emerged. The first was the sense that in normal practice therapists act as “benign dictators”, committed to help their patients, but most comfortable when they, the professional, are in control. Following the adoption of the self-management approach therapists challenged themselves to empower stroke survivors to take control of their own recovery. However, therapists had to confront many internal and external challenges in this transition of power resulting in the promotion of a somewhat “reluctant democracy”. Conclusions This study illustrates that stroke therapists desire a more participatory approach to rehabilitation. However, obstacles challenged the successful delivery of this goal. If self-management is an appropriate model to develop in post stroke pathways, then serious consideration must be given to how and if these obstacles can be overcome. Implications for Rehabilitation Stroke therapists perceive that self-management is appropriate for encouraging ownership of rehabilitation post stroke. Numerous obstacles were identified as challenging the implementation of self-management post stroke. These included: professional models, practices and expectations; institutional demands and perceived wishes of stroke survivors. For self-management to be effectively implemented by stroke therapists, these obstacles must be considered and overcome. This should be as part of an integrated therapy service, rather than as an add-on. PMID:23594054

From dictatorship to a reluctant democracy: stroke therapists talking about self-management.

PubMed

Norris, Meriel; Kilbride, Cherry

2014-01-01

Self-management is being increasingly promoted within chronic conditions including stroke. Concerns have been raised regarding professional ownership of some programmes, yet little is known of the professional's experience. This paper aims to present the views of trained therapists about the utility of a specific self-management approach in stroke rehabilitation. Eleven stroke therapists trained in the self-management approach participated in semi-structured interviews. These were audio recorded, transcribed verbatim and analysed thematically. Two overriding themes emerged. The first was the sense that in normal practice therapists act as "benign dictators", committed to help their patients, but most comfortable when they, the professional, are in control. Following the adoption of the self-management approach therapists challenged themselves to empower stroke survivors to take control of their own recovery. However, therapists had to confront many internal and external challenges in this transition of power resulting in the promotion of a somewhat "reluctant democracy". This study illustrates that stroke therapists desire a more participatory approach to rehabilitation. However, obstacles challenged the successful delivery of this goal. If self-management is an appropriate model to develop in post stroke pathways, then serious consideration must be given to how and if these obstacles can be overcome. Stroke therapists perceive that self-management is appropriate for encouraging ownership of rehabilitation post stroke. Numerous obstacles were identified as challenging the implementation of self-management post stroke. These included: professional models, practices and expectations; institutional demands and perceived wishes of stroke survivors. For self-management to be effectively implemented by stroke therapists, these obstacles must be considered and overcome. This should be as part of an integrated therapy service, rather than as an add-on.

Opportunities and obstacles to collecting wildlife disease data for public health purposes: Results of a pilot study on Vancouver Island, British Columbia

PubMed Central

Stitt, Tyler; Mountifield, Julie; Stephen, Craig

2007-01-01

Existing sources of wildlife morbidity and mortality data were evaluated and 3 pilot active surveillance projects were undertaken to compare and contrast methods for collecting wildlife disease data on Vancouver Island for public health purposes. Few organizations could collect samples for diagnostic evaluation, fewer still maintained records, and none regularly characterized or reported wildlife disease for public health purposes. Wildlife rehabilitation centers encountered the greatest variety of wildlife from the largest geographic area and frequently received submissions from other organizations. Obstacles to participation included the following: permit restrictions; financial disincentives; staff safety; no mandate to collect relevant data; and lack of contact between wildlife and public health agencies. Despite these obstacles, modest investments in personnel allowed novel pathogens of public health concern to be tracked. Targeted surveillance for known pathogens in specific host species, rather than general surveys for unspecified pathogens, was judged to be a more effective and efficient way to provide useful public health data. PMID:17310627

Law, policy and the use of non-physicians in family planning service delivery.

PubMed

Paxman, J M

1979-04-01

A great deal of attention is being devoted to the use of nonphysicians to provide such fertility control services as contraception, sterilization, and abortion. Legal obstacles exist, however, which must be overcome before the role of nonphysicians can be expanded. Such obstacles include medical practice statutes, nursing and midwifery legislation, and laws and regulations directly related to such fertility control measures as the provision of contraceptions and the performance of sterilizations. On the other hand, the following 3 main approaches have been used to permit increased participation of nonphysicians: delegation of tasks by physicians, liberal interpretation of existing laws, and authorization. Thus, the important elements in expanding the roles of nonphysicians are 1) authorization; 2) training; 3) qualification; 4) supervision; and 5) opportunities for referrals to physicians. The ultimate role of paramedicals will depend upon the continued simplification of technology, the results of research on the quality of care which they can provide, the attitudes of the medical profession, and the elimination of the legal ambiguities and obstacles which exist.

Indoor Navigation from Point Clouds: 3d Modelling and Obstacle Detection

NASA Astrophysics Data System (ADS)

Díaz-Vilariño, L.; Boguslawski, P.; Khoshelham, K.; Lorenzo, H.; Mahdjoubi, L.

2016-06-01

In the recent years, indoor modelling and navigation has become a research of interest because many stakeholders require navigation assistance in various application scenarios. The navigational assistance for blind or wheelchair people, building crisis management such as fire protection, augmented reality for gaming, tourism or training emergency assistance units are just some of the direct applications of indoor modelling and navigation. Navigational information is traditionally extracted from 2D drawings or layouts. Real state of indoors, including opening position and geometry for both windows and doors, and the presence of obstacles is commonly ignored. In this work, a real indoor-path planning methodology based on 3D point clouds is developed. The value and originality of the approach consist on considering point clouds not only for reconstructing semantically-rich 3D indoor models, but also for detecting potential obstacles in the route planning and using these for readapting the routes according to the real state of the indoor depictured by the laser scanner.

Tracked robot controllers for climbing obstacles autonomously

NASA Astrophysics Data System (ADS)

Vincent, Isabelle

2009-05-01

Research in mobile robot navigation has demonstrated some success in navigating flat indoor environments while avoiding obstacles. However, the challenge of analyzing complex environments to climb obstacles autonomously has had very little success due to the complexity of the task. Unmanned ground vehicles currently exhibit simple autonomous behaviours compared to the human ability to move in the world. This paper presents the control algorithms designed for a tracked mobile robot to autonomously climb obstacles by varying its tracks configuration. Two control algorithms are proposed to solve the autonomous locomotion problem for climbing obstacles. First, a reactive controller evaluates the appropriate geometric configuration based on terrain and vehicle geometric considerations. Then, a reinforcement learning algorithm finds alternative solutions when the reactive controller gets stuck while climbing an obstacle. The methodology combines reactivity to learning. The controllers have been demonstrated in box and stair climbing simulations. The experiments illustrate the effectiveness of the proposed approach for crossing obstacles.

Challenges in Learning to Speak Arabic

ERIC Educational Resources Information Center

Haron, Sueraya Che; Ahmed, Ismaiel Hassanien; Mamat, Arifin; Ahmad, Wan Rusli Wan; Rawash, Fouad Mahmoud M.

2016-01-01

This paper describes a study to investigate the challenges and obstacles to speaking Arabic faced by good and poor Malay speakers of Arabic. The study used individual and focus group interviews with 14 participants to elicit data. The findings revealed 2 types of obstacles, namely, internal and external obstacles. Internal obstacles refer to the…

Stochastic performance modeling and evaluation of obstacle detectability with imaging range sensors

NASA Technical Reports Server (NTRS)

Matthies, Larry; Grandjean, Pierrick

1993-01-01

Statistical modeling and evaluation of the performance of obstacle detection systems for Unmanned Ground Vehicles (UGVs) is essential for the design, evaluation, and comparison of sensor systems. In this report, we address this issue for imaging range sensors by dividing the evaluation problem into two levels: quality of the range data itself and quality of the obstacle detection algorithms applied to the range data. We review existing models of the quality of range data from stereo vision and AM-CW LADAR, then use these to derive a new model for the quality of a simple obstacle detection algorithm. This model predicts the probability of detecting obstacles and the probability of false alarms, as a function of the size and distance of the obstacle, the resolution of the sensor, and the level of noise in the range data. We evaluate these models experimentally using range data from stereo image pairs of a gravel road with known obstacles at several distances. The results show that the approach is a promising tool for predicting and evaluating the performance of obstacle detection with imaging range sensors.

The quality of visual information about the lower extremities influences visuomotor coordination during virtual obstacle negotiation.

PubMed

Kim, Aram; Kretch, Kari S; Zhou, Zixuan; Finley, James M

2018-05-09

Successful negotiation of obstacles during walking relies on the integration of visual information about the environment with ongoing locomotor commands. When information about the body and environment are removed through occlusion of the lower visual field, individuals increase downward head pitch angle, reduce foot placement precision, and increase safety margins during crossing. However, whether these effects are mediated by loss of visual information about the lower extremities, the obstacle, or both remains to be seen. Here, we used a fully immersive, virtual obstacle negotiation task to investigate how visual information about the lower extremities is integrated with information about the environment to facilitate skillful obstacle negotiation. Participants stepped over virtual obstacles while walking on a treadmill with one of three types of visual feedback about the lower extremities: no feedback, end-point feedback, or a link-segment model. We found that absence of visual information about the lower extremities led to an increase in the variability of leading foot placement after crossing. The presence of a visual representation of the lower extremities promoted greater downward head pitch angle during the approach to and subsequent crossing of an obstacle. In addition, having greater downward head pitch was associated with closer placement of the trailing foot to the obstacle, further placement of the leading foot after the obstacle, and higher trailing foot clearance. These results demonstrate that the fidelity of visual information about the lower extremities influences both feed-forward and feedback aspects of visuomotor coordination during obstacle negotiation.

Emerging Web Technologies in Higher Education: A Case of Incorporating Blogs, Podcasts and Social Bookmarks in a Web Programming Course Based on Students' Learning Styles and Technology Preferences

ERIC Educational Resources Information Center

Saeed, Nauman; Yang, Yun; Sinnappan, Suku

2009-01-01

The adoption level of emerging web technologies is on the rise in academic settings. However, a major obstacle in the practice of web-based instruction is the limited understanding of learners' characteristics and perceptions about technology use. Thus there is a need to understand the relationship between students' learning styles and their…

Clarifying values in psychotherapy.

PubMed

Horowitz, Mardi J

2014-12-01

This article addresses the complex issue of how to clarify conflicts involving value judgments. The author reviews his experiences as therapist, supervisor, and consultant in offering second opinions on in-progress therapies. He summarizes six major obstacles to effective value clarifications and interpretations. Therapists can help patients to explicitly verbalize otherwise only implicit values. Distress from guilt and shame can be reduced by helping a patient reprioritize values and gain self-reflective awareness skills for resolving moral dilemmas.

Quantitative Infrared Spectroscopy in Challenging Environments: Applications to Passive Remote Sensing and Process Monitoring

DTIC Science & Technology

2012-12-01

IR remote sensing o ers a measurement method to detect gaseous species in the outdoor environment. Two major obstacles limit the application of this... method in quantitative analysis : (1) the e ect of both temperature and concentration on the measured spectral intensities and (2) the di culty and...crucial. In this research, particle swarm optimization, a population- based optimization method was applied. Digital ltering and wavelet processing methods

Comunidad, Escuela y Curriculo 4: Materiales de Apoyo a La Formacion Docente en Educacion Bilingue Intercultural. (Community, School and Curriculum 4: Support Materials for Training Professionals in Bilingual Intercultural Education).

ERIC Educational Resources Information Center

Montaluisa Chasiquiza, Luis

The Major Project for Education for Latin America and the Caribbean has given indigenous populations priority attention and has sponsored workshops and seminars to address the educational needs of these peoples. Traditionally, the language and culture of indigenous peoples have been viewed as obstacles rather than valuable resources for education.…

Preventing Epilepsy After Traumatic Brain Injury

DTIC Science & Technology

2008-02-01

early seizures to the standard of care ( phenytoin ). A secondary objective is to obtain the data necessary to design a randomized clinical trial to...protocol was revised to eliminate several major obstacles. We have enrolled 5 subjects into the study; two in the phenytoin arm, one in the short term...prevent early seizures better than the current standard of care ( phenytoin ). A secondary objective is to obtain the data necessary to design a randomized

The flow across a street canyon of variable width—Part 2:. Scalar dispersion from a street level line source

NASA Astrophysics Data System (ADS)

Simoëns, Serge; Wallace, James M.

As described in Part 1 [Simoëns et al., 2007. The flow across a street canyon of variable width—Part 1: kinematic description. Atmospheric Environment 41, 9002-9017] measurements have been made of the velocity field around and within the canyon formed by two obstacles placed on the wall of a turbulent boundary layer. Here in Part 2 measurements of the scalar dispersion of smoke released from a two-dimensional slot in the wall perpendicular to the mean flow and located parallel to and midway between these two square obstacles are presented. The Reynolds number of the boundary layer at the slot location without the obstacles in place was Rθ≈980. Statistical properties of the concentration field and the scalar fluxes in the streamwise plane are reported here for canyon openings that have been chosen based on characteristics of the kinematic description. These opening widths, expressed as multiples of the obstacle height, are 1 h, 4 h and 8 h. The mean concentration field revealed that the much of the scalar is trapped on the leeward side of the upstream obstacle before some of it escapes the canyon and is entrained on the roof of the upstream obstacle. It then is spread downstream by the turbulence in the wake of this obstacle. Surprisingly, the root mean square (rms) concentration field reveals that high concentration fluctuations exist in a zone where velocity field turbulence is very low. Measured streamwise scalar fluxes were found to be negative above the obstacles, whereas they are mainly positive between the obstacles. The measured wall normal scalar fluxes have an inverse behavior. Within the canyon, the scalar fluxes are greatest in the region between the large primary vortex, evident in the kinematic field, and the secondary vortex located in the corner of the leeward side of the upstream obstacle. In the flow above the obstacle roofs the wake of the upstream obstacle seems to dominate the scalar transport. Between the obstacles in and above the canyon, the existence of intermittent and intense events appear to prevent the modelling of these fluxes with a simple mean concentration gradient model.

A Comparative Study of Randomized Constraint Solvers for Random-Symbolic Testing

NASA Technical Reports Server (NTRS)

Takaki, Mitsuo; Cavalcanti, Diego; Gheyi, Rohit; Iyoda, Juliano; dAmorim, Marcelo; Prudencio, Ricardo

2009-01-01

The complexity of constraints is a major obstacle for constraint-based software verification. Automatic constraint solvers are fundamentally incomplete: input constraints often build on some undecidable theory or some theory the solver does not support. This paper proposes and evaluates several randomized solvers to address this issue. We compare the effectiveness of a symbolic solver (CVC3), a random solver, three hybrid solvers (i.e., mix of random and symbolic), and two heuristic search solvers. We evaluate the solvers on two benchmarks: one consisting of manually generated constraints and another generated with a concolic execution of 8 subjects. In addition to fully decidable constraints, the benchmarks include constraints with non-linear integer arithmetic, integer modulo and division, bitwise arithmetic, and floating-point arithmetic. As expected symbolic solving (in particular, CVC3) subsumes the other solvers for the concolic execution of subjects that only generate decidable constraints. For the remaining subjects the solvers are complementary.

Emerging approaches in predictive toxicology.

PubMed

Zhang, Luoping; McHale, Cliona M; Greene, Nigel; Snyder, Ronald D; Rich, Ivan N; Aardema, Marilyn J; Roy, Shambhu; Pfuhler, Stefan; Venkatactahalam, Sundaresan

2014-12-01

Predictive toxicology plays an important role in the assessment of toxicity of chemicals and the drug development process. While there are several well-established in vitro and in vivo assays that are suitable for predictive toxicology, recent advances in high-throughput analytical technologies and model systems are expected to have a major impact on the field of predictive toxicology. This commentary provides an overview of the state of the current science and a brief discussion on future perspectives for the field of predictive toxicology for human toxicity. Computational models for predictive toxicology, needs for further refinement and obstacles to expand computational models to include additional classes of chemical compounds are highlighted. Functional and comparative genomics approaches in predictive toxicology are discussed with an emphasis on successful utilization of recently developed model systems for high-throughput analysis. The advantages of three-dimensional model systems and stem cells and their use in predictive toxicology testing are also described. © 2014 Wiley Periodicals, Inc.

Transfer Reactions and the Structure of Neutron-rich Nuclei

DOE PAGES

Kay, B. P.; Alcorta, M.; Back, B. B.; ...

2013-01-01

The study of transfer reactions in inverse kinematics is a major focus of existing and future radioactive-ion-beam facilities. One of the obstacles in such measurements is poor Q-value resolution, often several hundred keV, which can prevent the extraction of useful information. At Argonne National Laboratory, it has recently been demonstrated that good Q-value resolution can be achieved by transporting the outgoing ions through a high-field solenoid, measuring their position as a function of energy. Furthermore, this provides several advantages over conventional Si arrays, such as large acceptance, good particle identification, and most importantly a Q-value resolution of better than 100more » keV in most cases, including reactions with moderately heavy beams. In this paper, the concept of the solenoidal spectrometer, called HELIOS, will be discussed along with highlights of recent results.« less

Forward and store telemedicine using Motion Pictures Expert Group: a novel approach to pediatric tele-echocardiography.

PubMed

Woodson, Kristina E; Sable, Craig A; Cross, Russell R; Pearson, Gail D; Martin, Gerard R

2004-11-01

Live transmission of echocardiograms over integrated services digital network lines is accurate and has led to improvements in the delivery of pediatric cardiology care. Permanent archiving of the live studies has not previously been reported. Specific obstacles to permanent storage of telemedicine files have included the ability to produce accurate images without a significant increase in storage requirements. We evaluated the accuracy of Motion Pictures Expert Group (MPEG) digitization of incoming video streams and assessed the storage requirements of these files for infants in a real-time pediatric tele-echocardiography program. All major cardiac diagnoses were correctly diagnosed by review of MPEG images. MPEG file size ranged from 11.1 to 182 MB (56.5 +/- 29.9 MB). MPEG digitization during live neonatal telemedicine is accurate and provides an efficient method for storage. This modality has acceptable storage requirements; file sizes are comparable to other digital modalities.

Foe or friend? Janus-faces of the neurovascular unit in the formation of brain metastases.

PubMed

Wilhelm, Imola; Fazakas, Csilla; Molnár, Kinga; Végh, Attila G; Haskó, János; Krizbai, István A

2018-04-01

Despite the potential obstacle represented by the blood-brain barrier for extravasating malignant cells, metastases are more frequent than primary tumors in the central nervous system. Not only tightly interconnected endothelial cells can hinder metastasis formation, other cells of the brain microenvironment (like astrocytes and microglia) can also be very hostile, destroying the large majority of metastatic cells. However, malignant cells that are able to overcome these harmful mechanisms may benefit from the shielding and even support provided by cerebral endothelial cells, astrocytes and microglia, rendering the brain a sanctuary site against anti-tumor strategies. Thus, cells of the neurovascular unit have a Janus-faced attitude towards brain metastatic cells, being both destructive and protective. In this review, we present the main mechanisms of brain metastasis formation, including those involved in extravasation through the brain vasculature and survival in the cerebral environment.

It isn't all about language: communication barriers for Latinas using contraceptives.

PubMed

Campo, Shelly; Kohler, Connie; Askelson, Natoshia M; Ortiz, Cristina; Losch, Mary

2015-11-01

Little is known about barriers that Latinas in the United States face in preventing unintended pregnancies beyond those of language and cost. This study examined factors inhibiting contraceptive use among 18- to 30-year-old Latinas in the Midwest. Individual interviews (N = 31) were conducted in Spanish with Latinas residing across the state. The interview protocol included questions about contraceptives and unintended pregnancies. Interviews were recorded, transcribed, translated, and coded for themes related to barriers. The majority of the barriers were related to communication but not English proficiency. Respondents talked about specific situations and experiences in which communication presented obstacles to using contraceptives. While language and cost are important barriers, attention needs to be paid to the other communication issues that women face related to culture, religion, partners, family, and spontaneity. Health care providers need to address the range of communication barriers that affect Latinas' contraceptive use. © The Author(s) 2014.

Emerging Approaches in Predictive Toxicology

PubMed Central

Zhang, Luoping; McHale, Cliona M.; Greene, Nigel; Snyder, Ronald D.; Rich, Ivan N.; Aardema, Marilyn J.; Roy, Shambhu; Pfuhler, Stefan; Venkatactahalam, Sundaresan

2016-01-01

Predictive toxicology plays an important role in the assessment of toxicity of chemicals and the drug development process. While there are several well-established in vitro and in vivo assays that are suitable for predictive toxicology, recent advances in high-throughput analytical technologies and model systems are expected to have a major impact on the field of predictive toxicology. This commentary provides an overview of the state of the current science and a brief discussion on future perspectives for the field of predictive toxicology for human toxicity. Computational models for predictive toxicology, needs for further refinement and obstacles to expand computational models to include additional classes of chemical compounds are highlighted. Functional and comparative genomics approaches in predictive toxicology are discussed with an emphasis on successful utilization of recently developed model systems for high-throughput analysis. The advantages of three-dimensional model systems and stem cells and their use in predictive toxicology testing are also described. PMID:25044351

One-dimensional manganese-cobalt oxide nanofibres as bi-functional cathode catalysts for rechargeable metal-air batteries

PubMed Central

Jung, Kyu-Nam; Hwang, Soo Min; Park, Min-Sik; Kim, Ki Jae; Kim, Jae-Geun; Dou, Shi Xue; Kim, Jung Ho; Lee, Jong-Won

2015-01-01

Rechargeable metal-air batteries are considered a promising energy storage solution owing to their high theoretical energy density. The major obstacles to realising this technology include the slow kinetics of oxygen reduction and evolution on the cathode (air electrode) upon battery discharging and charging, respectively. Here, we report non-precious metal oxide catalysts based on spinel-type manganese-cobalt oxide nanofibres fabricated by an electrospinning technique. The spinel oxide nanofibres exhibit high catalytic activity towards both oxygen reduction and evolution in an alkaline electrolyte. When incorporated as cathode catalysts in Zn-air batteries, the fibrous spinel oxides considerably reduce the discharge-charge voltage gaps (improve the round-trip efficiency) in comparison to the catalyst-free cathode. Moreover, the nanofibre catalysts remain stable over the course of repeated discharge-charge cycling; however, carbon corrosion in the catalyst/carbon composite cathode degrades the cycling performance of the batteries. PMID:25563733

Non-clinical influences on clinical decision-making: a major challenge to evidence-based practice.

PubMed

Hajjaj, F M; Salek, M S; Basra, M K A; Finlay, A Y

2010-05-01

This article reviews an aspect of daily clinical practice which is of critical importance in virtually every clinical consultation, but which is seldom formally considered. Non-clinical influences on clinical decision-making profoundly affect medical decisions. These influences include patient-related factors such as socioeconomic status, quality of life and patient's expectations and wishes, physician-related factors such as personal characteristics and interaction with their professional community, and features of clinical practice such as private versus public practice as well as local management policies. This review brings together the different strands of knowledge concerning non-clinical influences on clinical decision-making. This aspect of decision-making may be the biggest obstacle to the reality of practising evidence-based medicine. It needs to be understood in order to develop clinical strategies that will facilitate the practice of evidence-based medicine.

Si/Ge double-layered nanotube array as a lithium ion battery anode.

PubMed

Song, Taeseup; Cheng, Huanyu; Choi, Heechae; Lee, Jin-Hyon; Han, Hyungkyu; Lee, Dong Hyun; Yoo, Dong Su; Kwon, Moon-Seok; Choi, Jae-Man; Doo, Seok Gwang; Chang, Hyuk; Xiao, Jianliang; Huang, Yonggang; Park, Won Il; Chung, Yong-Chae; Kim, Hansu; Rogers, John A; Paik, Ungyu

2012-01-24

Problems related to tremendous volume changes associated with cycling and the low electron conductivity and ion diffusivity of Si represent major obstacles to its use in high-capacity anodes for lithium ion batteries. We have developed a group IVA based nanotube heterostructure array, consisting of a high-capacity Si inner layer and a highly conductive Ge outer layer, to yield both favorable mechanics and kinetics in battery applications. This type of Si/Ge double-layered nanotube array electrode exhibits improved electrochemical performances over the analogous homogeneous Si system, including stable capacity retention (85% after 50 cycles) and doubled capacity at a 3C rate. These results stem from reduced maximum hoop strain in the nanotubes, supported by theoretical mechanics modeling, and lowered activation energy barrier for Li diffusion. This electrode technology creates opportunities in the development of group IVA nanotube heterostructures for next generation lithium ion batteries. © 2011 American Chemical Society

Financing mental health services for adolescents: a background paper.

PubMed

Kapphahn, Cynthia; Morreale, Madlyn; Rickert, Vaughn I; Walker, Leslie

2006-09-01

Good mental health provides an essential foundation for normal growth and development through adolescence and into adulthood. Many adolescents, however, experience mental health problems that significantly impede the attainment of their full potential. The majority of these adolescents do not receive needed mental health services, in part because of financial obstacles to care. This article reviews the magnitude and impact of mental health problems during adolescence and highlights the importance of insurance coverage in assuring access to mental health services for adolescents. Significant limitations in private health insurance coverage of mental health services are outlined. Recent federal and state efforts to move toward parity in private insurance coverage between mental and physical health services are discussed, including an explanation of the role of Medicaid and the State Children's Health Insurance Program (SCHIP) in providing access to mental health services for adolescents. Finally, other elements that would facilitate financial access to essential mental health services for adolescents are presented.

Analytical and Biological Methods for Probing the Blood-Brain Barrier

PubMed Central

Sloan, Courtney D. Kuhnline; Nandi, Pradyot; Linz, Thomas H.; Aldrich, Jane V.; Audus, Kenneth L.; Lunte, Susan M.

2013-01-01

The blood-brain barrier (BBB) is an important interface between the peripheral and central nervous systems. It protects the brain against the infiltration of harmful substances and regulates the permeation of beneficial endogenous substances from the blood into the extracellular fluid of the brain. It can also present a major obstacle in the development of drugs that are targeted for the central nervous system. Several methods have been developed to investigate the transport and metabolism of drugs, peptides, and endogenous compounds at the BBB. In vivo methods include intravenous injection, brain perfusion, positron emission tomography, and microdialysis sampling. Researchers have also developed in vitro cell-culture models that can be employed to investigate transport and metabolism at the BBB without the complication of systemic involvement. All these methods require sensitive and selective analytical methods to monitor the transport and metabolism of the compounds of interest at the BBB. PMID:22708905

Insights and limits of translational research in critical care medicine.

PubMed

Pène, Frédéric; Ait-Oufella, Hafid; Taccone, Fabio Silvio; Monneret, Guillaume; Sharshar, Tarek; Tamion, Fabienne; Mira, Jean-Paul

2015-01-01

Experimental research has always been the cornerstone of pathophysiological and therapeutic advances in critical care medicine, where clinical observations and basic research mutually fed each other in a so-called translational approach. The objective of this review is to address the different aspects of translational research in the field of critical care medicine. We herein highlighted some demonstrative examples including the animal-to-human approach to study host-pathogen interactions, the human-to-animal approach for sepsis-induced immunosuppression, the still restrictive human approach to study critical illness-related neuromyopathy, and the technological developments to assess the microcirculatory changes in critically ill patients. These examples not only emphasize how translational research resulted in major improvements in the comprehension of the pathophysiology of severe clinical conditions and offered promising perspectives in critical care medicine but also point out the obstacles to translate such achievements into clinical practice.

Quantifying Genome Editing Outcomes at Endogenous Loci using SMRT Sequencing

PubMed Central

Clark, Joseph; Punjya, Niraj; Sebastiano, Vittorio; Bao, Gang; Porteus, Matthew H

2014-01-01

SUMMARY Targeted genome editing with engineered nucleases has transformed the ability to introduce precise sequence modifications at almost any site within the genome. A major obstacle to probing the efficiency and consequences of genome editing is that no existing method enables the frequency of different editing events to be simultaneously measured across a cell population at any endogenous genomic locus. We have developed a novel method for quantifying individual genome editing outcomes at any site of interest using single molecule real time (SMRT) DNA sequencing. We show that this approach can be applied at various loci, using multiple engineered nuclease platforms including TALENs, RNA guided endonucleases (CRISPR/Cas9), and ZFNs, and in different cell lines to identify conditions and strategies in which the desired engineering outcome has occurred. This approach facilitates the evaluation of new gene editing technologies and permits sensitive quantification of editing outcomes in almost every experimental system used. PMID:24685129

Identification of Neurodegenerative Factors Using Translatome-Regulatory Network Analysis

PubMed Central

Brichta, Lars; Shin, William; Jackson-Lewis, Vernice; Blesa, Javier; Yap, Ee-Lynn; Walker, Zachary; Zhang, Jack; Roussarie, Jean-Pierre; Alvarez, Mariano J.; Califano, Andrea; Przedborski, Serge; Greengard, Paul

2016-01-01

For degenerative disorders of the central nervous system, the major obstacle to therapeutic advancement has been the challenge of identifying the key molecular mechanisms underlying neuronal loss. We developed a combinatorial approach including translational profiling and brain regulatory network analysis to search for key determinants of neuronal survival or death. Following the generation of transgenic mice for cell type-specific profiling of midbrain dopaminergic neurons, we established and compared translatome libraries reflecting the molecular signature of these cells at baseline or under degenerative stress. Analysis of these libraries by interrogating a context-specific brain regulatory network led to the identification of a repertoire of intrinsic upstream regulators that drive the dopaminergic stress response. The altered activity of these regulators was not associated with changes in their expression levels. This strategy can be generalized for the elucidation of novel molecular determinants involved in the degeneration of other classes of neurons. PMID:26214373

Construction of membrane-bound artificial cells using microfluidics: a new frontier in bottom-up synthetic biology.

PubMed

Elani, Yuval

2016-06-15

The quest to construct artificial cells from the bottom-up using simple building blocks has received much attention over recent decades and is one of the grand challenges in synthetic biology. Cell mimics that are encapsulated by lipid membranes are a particularly powerful class of artificial cells due to their biocompatibility and the ability to reconstitute biological machinery within them. One of the key obstacles in the field centres on the following: how can membrane-based artificial cells be generated in a controlled way and in high-throughput? In particular, how can they be constructed to have precisely defined parameters including size, biomolecular composition and spatial organization? Microfluidic generation strategies have proved instrumental in addressing these questions. This article will outline some of the major principles underpinning membrane-based artificial cells and their construction using microfluidics, and will detail some recent landmarks that have been achieved. © 2016 The Author(s).

Challenges facing early career academic cardiologists.

PubMed

Tong, Carl W; Ahmad, Tariq; Brittain, Evan L; Bunch, T Jared; Damp, Julie B; Dardas, Todd; Hijar, Amalea; Hill, Joseph A; Hilliard, Anthony A; Houser, Steven R; Jahangir, Eiman; Kates, Andrew M; Kim, Darlene; Lindman, Brian R; Ryan, John J; Rzeszut, Anne K; Sivaram, Chittur A; Valente, Anne Marie; Freeman, Andrew M

2014-06-03

Early career academic cardiologists currently face unprecedented challenges that threaten a highly valued career path. A team consisting of early career professionals and senior leadership members of American College of Cardiology completed this white paper to inform the cardiovascular medicine profession regarding the plight of early career cardiologists and to suggest possible solutions. This paper includes: 1) definition of categories of early career academic cardiologists; 2) general challenges to all categories and specific challenges to each category; 3) obstacles as identified by a survey of current early career members of the American College of Cardiology; 4) major reasons for the failure of physician-scientists to receive funding from National Institute of Health/National Heart Lung and Blood Institute career development grants; 5) potential solutions; and 6) a call to action with specific recommendations. Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Bushmeat hunting and extinction risk to the world's mammals

PubMed Central

Abernethy, Katharine; Betts, Matthew G.; Chapron, Guillaume; Dirzo, Rodolfo; Galetti, Mauro; Levi, Taal; Lindsey, Peter A.; Macdonald, David W.; Machovina, Brian; Peres, Carlos A.; Wallach, Arian D.

2016-01-01

Terrestrial mammals are experiencing a massive collapse in their population sizes and geographical ranges around the world, but many of the drivers, patterns and consequences of this decline remain poorly understood. Here we provide an analysis showing that bushmeat hunting for mostly food and medicinal products is driving a global crisis whereby 301 terrestrial mammal species are threatened with extinction. Nearly all of these threatened species occur in developing countries where major coexisting threats include deforestation, agricultural expansion, human encroachment and competition with livestock. The unrelenting decline of mammals suggests many vital ecological and socio-economic services that these species provide will be lost, potentially changing ecosystems irrevocably. We discuss options and current obstacles to achieving effective conservation, alongside consequences of failure to stem such anthropogenic mammalian extirpation. We propose a multi-pronged conservation strategy to help save threatened mammals from immediate extinction and avoid a collapse of food security for hundreds of millions of people. PMID:27853564

Minimally Invasive Calcaneal Displacement Osteotomy Site Using a Reference Kirschner Wire: A Technique Tip.

PubMed

Lee, Moses; Guyton, Gregory P; Zahoor, Talal; Schon, Lew C

2016-01-01

As a standard open approach, the lateral oblique incision has been widely used for calcaneal displacement osteotomy. However, just as with other orthopedic procedures that use an open approach, complications, including wound healing problems and neurovascular injury in the heel, have been reported. To help avoid these limitations, a percutaneous technique using a Shannon burr for calcaneal displacement osteotomy was introduced. However, relying on a free-hand technique without direct visualization at the osteotomy site has been a major obstacle for this technique. To address this problem, we developed a technical tip using a reference Kirschner wire. A reference Kirschner wire technique provides a reliable and accurate guide for minimally invasive calcaneal displacement osteotomy. Also, the technique should be easy to learn for surgeons new to the procedure. Copyright © 2016 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

Bromelain Surface Modification Increases the Diffusion of Silica Nanoparticles in the Tumor Extracellular Matrix

PubMed Central

2015-01-01

Tumor extracellular matrix (ECM) represents a major obstacle to the diffusion of therapeutics and drug delivery systems in cancer parenchyma. This biological barrier limits the efficacy of promising therapeutic approaches including the delivery of siRNA or agents intended for thermoablation. After extravasation due to the enhanced penetration and retention effect of tumor vasculature, typical nanotherapeutics are unable to reach the nonvascularized and anoxic regions deep within cancer parenchyma. Here, we developed a simple method to provide mesoporous silica nanoparticles (MSN) with a proteolytic surface. To this extent, we chose to conjugate MSN to Bromelain (Br–MSN), a crude enzymatic complex, purified from pineapple stems, that belongs to the peptidase papain family. This surface modification increased particle uptake in endothelial, macrophage, and cancer cell lines with minimal impact on cellular viability. Most importantly Br–MSN showed an increased ability to digest and diffuse in tumor ECM in vitro and in vivo. PMID:25119793

Bromelain surface modification increases the diffusion of silica nanoparticles in the tumor extracellular matrix.

PubMed

Parodi, Alessandro; Haddix, Seth G; Taghipour, Nima; Scaria, Shilpa; Taraballi, Francesca; Cevenini, Armando; Yazdi, Iman K; Corbo, Claudia; Palomba, Roberto; Khaled, Sm Z; Martinez, Jonathan O; Brown, Brandon S; Isenhart, Lucas; Tasciotti, Ennio

2014-10-28

Tumor extracellular matrix (ECM) represents a major obstacle to the diffusion of therapeutics and drug delivery systems in cancer parenchyma. This biological barrier limits the efficacy of promising therapeutic approaches including the delivery of siRNA or agents intended for thermoablation. After extravasation due to the enhanced penetration and retention effect of tumor vasculature, typical nanotherapeutics are unable to reach the nonvascularized and anoxic regions deep within cancer parenchyma. Here, we developed a simple method to provide mesoporous silica nanoparticles (MSN) with a proteolytic surface. To this extent, we chose to conjugate MSN to Bromelain (Br-MSN), a crude enzymatic complex, purified from pineapple stems, that belongs to the peptidase papain family. This surface modification increased particle uptake in endothelial, macrophage, and cancer cell lines with minimal impact on cellular viability. Most importantly Br-MSN showed an increased ability to digest and diffuse in tumor ECM in vitro and in vivo.

Brief Report: Databases in the Asia-Pacific Region: The Potential for a Distributed Network Approach.

PubMed

Lai, Edward Chia-Cheng; Man, Kenneth K C; Chaiyakunapruk, Nathorn; Cheng, Ching-Lan; Chien, Hsu-Chih; Chui, Celine S L; Dilokthornsakul, Piyameth; Hardy, N Chantelle; Hsieh, Cheng-Yang; Hsu, Chung Y; Kubota, Kiyoshi; Lin, Tzu-Chieh; Liu, Yanfang; Park, Byung Joo; Pratt, Nicole; Roughead, Elizabeth E; Shin, Ju-Young; Watcharathanakij, Sawaeng; Wen, Jin; Wong, Ian C K; Yang, Yea-Huei Kao; Zhang, Yinghong; Setoguchi, Soko

2015-11-01

This study describes the availability and characteristics of databases in Asian-Pacific countries and assesses the feasibility of a distributed network approach in the region. A web-based survey was conducted among investigators using healthcare databases in the Asia-Pacific countries. Potential survey participants were identified through the Asian Pharmacoepidemiology Network. Investigators from a total of 11 databases participated in the survey. Database sources included four nationwide claims databases from Japan, South Korea, and Taiwan; two nationwide electronic health records from Hong Kong and Singapore; a regional electronic health record from western China; two electronic health records from Thailand; and cancer and stroke registries from Taiwan. We identified 11 databases with capabilities for distributed network approaches. Many country-specific coding systems and terminologies have been already converted to international coding systems. The harmonization of health expenditure data is a major obstacle for future investigations attempting to evaluate issues related to medical costs.

Case management and adherence to an online disease management system.

PubMed

Robertson, Lucy; Smith, Michael; Tannenbaum, Dennis

2005-01-01

Non-adherence to treatment presents a significant obstacle to achieving favourable health outcomes. We have studied consumers' adherence to an online disease management system for depression, called Recovery Road. Recovery Road was implemented on a pilot basis for mental health care in Western Australia. Recovery Road was available for use by consumers and clinicians to augment usual treatment. One hundred and thirty consumers who had been diagnosed with major depression were enrolled. Consumers who used Recovery Road (n = 98) were provided with education, progress monitoring, e-consultation, e-diary and online evidenced-based therapy. Consumers received either standard, automated adherence reminders by email (n = 69), or case management, which included personalized email and telephone follow-up in response to non-adherence (n = 29). After the first eight sessions, the adherence was 84% in the case management group and 55% in the automatic reminders group. The results suggest that case management increases adherence to online disease management systems.

Knowledge, Attitudes, and Beliefs Toward Organ Donation Among Social Media Users.

PubMed

Hajjar, W M; Bin Abdulqader, S A; Aldayel, S S; Alfardan, A W; Alzaidy, N I

2016-09-01

Organ transplantation is the optimal treatment for end-stage organ diseases. The demand for organs has exceeded the available supply, which becomes a major obstacle worldwide. Identifying the factors affecting this gap will help in overcoming this obstacle. The purpose of the work was to study the knowledge, attitudes, and beliefs of organ donation and to determine the knowledge of brain death among social media users. A cross-sectional study was conducted among social media users living in Saudi Arabia. A pre-designed self-administrated questionnaire was distributed online randomly on social media networks in 2015. Of the total 1368 participants, only 913 met the criteria. Most respondents were between 18 and 29 years of age (61.2%) and living in the central region of Saudi Arabia (64.5%). The majority of respondents received their information from television (57%) and social media (50%) networks; 46.4% of respondents knew that the religious fatwa allowed organ donation; 51% of respondents were willing to donate their organs; 46.5% considered the brain-dead to be deceased, whereas 37.7% considered it a coma; 33.3% did not know if someone who was brain-dead would ever wake up; on the other hand, 323 (35.4%) said yes. Our study showed that the vast majority of our sample had enough information about organ donation. On the contrary, they had minimal knowledge about brain death. Moreover, a fair percentage of the participants had positive attitudes toward organ donation. Also, the media had a significant effect on the information about organ donation and brain death. Copyright © 2016 Elsevier Inc. All rights reserved.