Search efficiency of biased migration towards stationary or moving targets in heterogeneously structured environments

NASA Astrophysics Data System (ADS)

Azimzade, Youness; Mashaghi, Alireza

2017-12-01

Efficient search acts as a strong selective force in biological systems ranging from cellular populations to predator-prey systems. The search processes commonly involve finding a stationary or mobile target within a heterogeneously structured environment where obstacles limit migration. An open generic question is whether random or directionally biased motions or a combination of both provide an optimal search efficiency and how that depends on the motility and density of targets and obstacles. To address this question, we develop a simple model that involves a random walker searching for its targets in a heterogeneous medium of bond percolation square lattice and used mean first passage time (〈T 〉 ) as an indication of average search time. Our analysis reveals a dual effect of directional bias on the minimum value of 〈T 〉 . For a homogeneous medium, directionality always decreases 〈T 〉 and a pure directional migration (a ballistic motion) serves as the optimized strategy, while for a heterogeneous environment, we find that the optimized strategy involves a combination of directed and random migrations. The relative contribution of these modes is determined by the density of obstacles and motility of targets. Existence of randomness and motility of targets add to the efficiency of search. Our study reveals generic and simple rules that govern search efficiency. Our findings might find application in a number of areas including immunology, cell biology, ecology, and robotics.

Mesenchymal stem cell-mediated cancer therapy: A dual-targeted strategy of personalized medicine

PubMed Central

Sun, Xu-Yong; Nong, Jiang; Qin, Ke; Warnock, Garth L; Dai, Long-Jun

2011-01-01

Cancer remains one of the leading causes of mortality and morbidity throughout the world. To a significant extent, current conventional cancer therapies are symptomatic and passive in nature. The major obstacle to the development of effective cancer therapy is believed to be the absence of sufficient specificity. Since the discovery of the tumor-oriented homing capacity of mesenchymal stem cells (MSCs), the application of specific anticancer gene-engineered MSCs has held great potential for cancer therapies. The dual-targeted strategy is based on MSCs’ capacity of tumor-directed migration and incorporation and in situ expression of tumor-specific anticancer genes. With the aim of translating bench work into meaningful clinical applications, we describe the tumor tropism of MSCs and their use as therapeutic vehicles, the dual-targeted anticancer potential of engineered MSCs and a putative personalized strategy with anticancer gene-engineered MSCs. PMID:22180830

Speeded Reaching Movements around Invisible Obstacles

PubMed Central

Hudson, Todd E.; Wolfe, Uta; Maloney, Laurence T.

2012-01-01

We analyze the problem of obstacle avoidance from a Bayesian decision-theoretic perspective using an experimental task in which reaches around a virtual obstacle were made toward targets on an upright monitor. Subjects received monetary rewards for touching the target and incurred losses for accidentally touching the intervening obstacle. The locations of target-obstacle pairs within the workspace were varied from trial to trial. We compared human performance to that of a Bayesian ideal movement planner (who chooses motor strategies maximizing expected gain) using the Dominance Test employed in Hudson et al. (2007). The ideal movement planner suffers from the same sources of noise as the human, but selects movement plans that maximize expected gain in the presence of that noise. We find good agreement between the predictions of the model and actual performance in most but not all experimental conditions. PMID:23028276

Analysis of Core Stability Exercise Effect on the Physical and Psychological Function of Elderly Women Vulnerable to Falls during Obstacle Negotiation.

PubMed

Ko, Dae-Sik; Jung, Dae-In; Jeong, Mi-Ae

2014-11-01

[Purpose] The aim of the present study was to investigate the effects of core stability exercise (CSE) on the physical and psychological functions of elderly women while negotiating general obstacles. [Subjects and Methods] After allocating 10 elderly women each to the core stability training group and the control group, we carried out Performance-Oriented Mobility Assessment (POMA) and measured crossing velocity (CV), maximum vertical heel clearance (MVHC), and knee flexion angle for assessing physical performances. We evaluated depression and fear of falling for assessing psychological functions. [Results] Relative to the control group, the core stability training group showed statistically significant overall changes after the training session: an increase in POMA scores, faster CV, lower MVHC, and a decrease in knee flexion angle. Furthermore, depression and fear of falling decreased significantly. [Conclusion] CSE can have a positive effect on the improvement of physical and psychological performances of older women who are vulnerable to falls as they negotiate everyday obstacles.

An informal analysis of flight control tasks

NASA Technical Reports Server (NTRS)

Andersen, George J.

1991-01-01

Issues important in rotorcraft flight control are discussed. A perceptual description is suggested of what is believed to be the major issues in flight control. When the task is considered of a pilot controlling a helicopter in flight, the task is decomposed in several subtasks. These subtasks include: (1) the control of altitude, (2) the control of speed, (3) the control of heading, (4) the control of orientation, (5) the control of flight over obstacles, and (6) the control of flight to specified positions in the world. The first four subtasks can be considered to be primary control tasks as they are not dependent on any other subtasks. However, the latter two subtasks can be considered hierarchical tasks as they are dependent on other subtasks. For example, the task of flight control over obstacles can be decomposed as a task requiring the control of speed, altitude, and heading. Thus, incorrect control of altitude should result in poor control of flight over an obstacle.

Obstacle Avoidance and Target Acquisition for Robot Navigation Using a Mixed Signal Analog/Digital Neuromorphic Processing System

PubMed Central

Milde, Moritz B.; Blum, Hermann; Dietmüller, Alexander; Sumislawska, Dora; Conradt, Jörg; Indiveri, Giacomo; Sandamirskaya, Yulia

2017-01-01

Neuromorphic hardware emulates dynamics of biological neural networks in electronic circuits offering an alternative to the von Neumann computing architecture that is low-power, inherently parallel, and event-driven. This hardware allows to implement neural-network based robotic controllers in an energy-efficient way with low latency, but requires solving the problem of device variability, characteristic for analog electronic circuits. In this work, we interfaced a mixed-signal analog-digital neuromorphic processor ROLLS to a neuromorphic dynamic vision sensor (DVS) mounted on a robotic vehicle and developed an autonomous neuromorphic agent that is able to perform neurally inspired obstacle-avoidance and target acquisition. We developed a neural network architecture that can cope with device variability and verified its robustness in different environmental situations, e.g., moving obstacles, moving target, clutter, and poor light conditions. We demonstrate how this network, combined with the properties of the DVS, allows the robot to avoid obstacles using a simple biologically-inspired dynamics. We also show how a Dynamic Neural Field for target acquisition can be implemented in spiking neuromorphic hardware. This work demonstrates an implementation of working obstacle avoidance and target acquisition using mixed signal analog/digital neuromorphic hardware. PMID:28747883

Obstacle Avoidance and Target Acquisition for Robot Navigation Using a Mixed Signal Analog/Digital Neuromorphic Processing System.

PubMed

Milde, Moritz B; Blum, Hermann; Dietmüller, Alexander; Sumislawska, Dora; Conradt, Jörg; Indiveri, Giacomo; Sandamirskaya, Yulia

2017-01-01

Neuromorphic hardware emulates dynamics of biological neural networks in electronic circuits offering an alternative to the von Neumann computing architecture that is low-power, inherently parallel, and event-driven. This hardware allows to implement neural-network based robotic controllers in an energy-efficient way with low latency, but requires solving the problem of device variability, characteristic for analog electronic circuits. In this work, we interfaced a mixed-signal analog-digital neuromorphic processor ROLLS to a neuromorphic dynamic vision sensor (DVS) mounted on a robotic vehicle and developed an autonomous neuromorphic agent that is able to perform neurally inspired obstacle-avoidance and target acquisition. We developed a neural network architecture that can cope with device variability and verified its robustness in different environmental situations, e.g., moving obstacles, moving target, clutter, and poor light conditions. We demonstrate how this network, combined with the properties of the DVS, allows the robot to avoid obstacles using a simple biologically-inspired dynamics. We also show how a Dynamic Neural Field for target acquisition can be implemented in spiking neuromorphic hardware. This work demonstrates an implementation of working obstacle avoidance and target acquisition using mixed signal analog/digital neuromorphic hardware.

Constructing target product profiles (TPPs) to help vaccines overcome post-approval obstacles

PubMed Central

Lee, Bruce Y.; Burke, Donald S.

2012-01-01

As history has demonstrated, post-approval obstacles can impede a vaccine’s use and potentially lead to its withdrawal. Addressing these potential obstacles when changes in a vaccine’s technology can still be easily made may improve a vaccine’s chances of success. Augmented vaccine target product profiles (TPPs) can help vaccine scientists better understand and anticipate these obstacles and galvanize conversations among various vaccine stakeholders (e.g., scientists, marketers, business development managers, policy makers, public health officials, health care workers, third party payors, etc.) earlier in a vaccine’s development. PMID:19782109

Anomalous behaviors during infiltration into heterogeneous porous media

NASA Astrophysics Data System (ADS)

Aarão Reis, F. D. A.; Bolster, D.; Voller, V. R.

2018-03-01

Flow and transport in heterogeneous porous media often exhibit anomalous behavior. A physical analog example is the uni-directional infiltration of a viscous liquid into a horizontal oriented Hele-Shaw cell containing through thickness flow obstacles; a system designed to mimic a gravel/sand medium with impervious inclusions. When there are no obstacles present or the obstacles form a multi-repeating pattern, the change of the length of infiltration F with time t tends to follow a Fickian like scaling, F ∼t1/2 . In the presence of obstacle fields laid out as Sierpinski carpet fractals, infiltration is anomalous, i.e., F ∼ tn, n ≠ 1/2. Here, we study infiltration into such Hele-Shaw cells. First we investigate infiltration into a square cell containing one fractal carpet and make the observation that it is possible to generate both sub (n < 1/2) and super (n > 1/2) diffusive behaviors within identical heterogeneity configurations. We show that this can be explained in terms of a scaling analysis developed from results of random-walk simulations in fractal obstacles; a result indicating that the nature of the domain boundary controls the exponent n of the resulting anomalous transport. Further, we investigate infiltration into a rectangular cell containing several repeats of a given Sierpinski carpet. At very early times, before the liquid encounters any obstacles, the infiltration is Fickian. When the liquid encounters the first (smallest scale) obstacle the infiltration sharply transitions to sub-diffusive. Subsequently, around the time where the liquid has sampled all of the heterogeneity length scales in the system, there is a rapid transition back to Fickian behavior. An explanation for this second transition is obtained by developing a simplified infiltration model based on the definition of a representative averaged hydraulic conductivity.

Understanding adaptive gait in lower-limb amputees: insights from multivariate analyses

PubMed Central

2013-01-01

Background In this paper we use multivariate statistical techniques to gain insights into how adaptive gait involving obstacle crossing is regulated in lower-limb amputees compared to able-bodied controls, with the aim of identifying underlying characteristics that differ between the two groups and consequently highlighting gait deficits in the amputees. Methods Eight unilateral trans-tibial amputees and twelve able-bodied controls completed adaptive gait trials involving negotiating various height obstacles; with amputees leading with their prosthetic limb. Spatiotemporal variables that are regularly used to quantify how gait is adapted when crossing obstacles were determined and subsequently analysed using multivariate statistical techniques. Results and discussion There were fundamental differences in the adaptive gait between the two groups. Compared to controls, amputees had a reduced approach velocity, reduced foot placement distance before and after the obstacle and reduced foot clearance over it, and reduced lead-limb knee flexion during the step following crossing. Logistic regression analysis highlighted the variables that best distinguished between the gait of the two groups and multiple regression analysis (with approach velocity as a controlling factor) helped identify what gait adaptations were driving the differences seen in these variables. Getting closer to the obstacle before crossing it appeared to be a strategy to ensure the heel of the lead-limb foot passed over the obstacle prior to the foot being lowered to the ground. Despite adopting such a heel clearance strategy, the lead-foot was positioned closer to the obstacle following crossing, which was likely a result of a desire to attain a limb/foot angle and orientation at instant of landing that minimised loads on the residuum (as evidenced by the reduced lead-limb knee flexion during the step following crossing). These changes in foot placement meant the foot was in a different part of swing at point of crossing and this explains why foot clearance was considerably reduced in amputees. Conclusions These results highlight that trans-tibial amputees use quite different gait adaptations to cross obstacles compared with controls (at least when leading with their prosthetic limb), indicating they are governed by different constraints; seemingly related to how they land on/load their prosthesis after crossing the obstacle. PMID:23958032

A bio-inspired kinematic controller for obstacle avoidance during reaching tasks with real robots.

PubMed

Srinivasa, Narayan; Bhattacharyya, Rajan; Sundareswara, Rashmi; Lee, Craig; Grossberg, Stephen

2012-11-01

This paper describes a redundant robot arm that is capable of learning to reach for targets in space in a self-organized fashion while avoiding obstacles. Self-generated movement commands that activate correlated visual, spatial and motor information are used to learn forward and inverse kinematic control models while moving in obstacle-free space using the Direction-to-Rotation Transform (DIRECT). Unlike prior DIRECT models, the learning process in this work was realized using an online Fuzzy ARTMAP learning algorithm. The DIRECT-based kinematic controller is fault tolerant and can handle a wide range of perturbations such as joint locking and the use of tools despite not having experienced them during learning. The DIRECT model was extended based on a novel reactive obstacle avoidance direction (DIRECT-ROAD) model to enable redundant robots to avoid obstacles in environments with simple obstacle configurations. However, certain configurations of obstacles in the environment prevented the robot from reaching the target with purely reactive obstacle avoidance. To address this complexity, a self-organized process of mental rehearsals of movements was modeled, inspired by human and animal experiments on reaching, to generate plans for movement execution using DIRECT-ROAD in complex environments. These mental rehearsals or plans are self-generated by using the Fuzzy ARTMAP algorithm to retrieve multiple solutions for reaching each target while accounting for all the obstacles in its environment. The key aspects of the proposed novel controller were illustrated first using simple examples. Experiments were then performed on real robot platforms to demonstrate successful obstacle avoidance during reaching tasks in real-world environments. Copyright © 2012 Elsevier Ltd. All rights reserved.

Identifying and Predicting Profiles of Medical Noncompliance: Pediatric Caregivers' Antibiotic Stewardship.

PubMed

Smith, Rachel A; Kim, Youllee; M'Ikanatha, Nkuchia M

2018-05-14

Sometimes compliance with medical recommendations is problematic. We investigated pediatric caregivers' (N = 606) patterns of noncompliance with antibiotic stewardship based on the obstacle hypothesis. We tested predictors of noncompliance framed by the obstacle hypothesis, dissonance theory, and psychological reactance. The results revealed four profiles of caregivers' stewardship: one marked by compliance (Stewards) and three marked by types of noncompliance (Stockers, Persuaders, and Dissenters). The covariate analysis showed that, although psychological reactance predicted being noncompliant, it was types of obstacles and discrepant experiences that predicted caregivers' patterns of noncompliance with antibiotic stewardship. Campaign planning often focuses on identifying the belief most associated with the targeted outcome, such as compliance. Noncompliance research, however, points out that persuaders may be successful to the extent to which they anticipate obstacles to compliance and address them in their influence attempts. A shift from medical noncompliance to patient engagement also affords an opportunity to consider how some recommendations create obstacles for others and to find positive ways to embrace conflicting needs, tensions, and reasons for refusal in order to promote collective goals.

Diverting lava flows in the lab

USGS Publications Warehouse

Dietterich, Hannah; Cashman, Katharine V.; Rust, Alison C.; Lev, Einat

2015-01-01

Recent volcanic eruptions in Hawai'i, Iceland and Cape Verde highlight the challenges of mitigating hazards when lava flows threaten infrastructure. Diversion barriers are the most common form of intervention, but historical attempts to divert lava flows have met with mixed success and there has been little systematic analysis of optimal barrier design. We examine the interaction of viscous flows of syrup and molten basalt with barriers in the laboratory. We find that flows thicken immediately upslope of an obstacle, forming a localized bow wave that can overtop barriers. Larger bow waves are generated by faster flows and by obstacles oriented at a high angle to the flow direction. The geometry of barriers also influences flow behaviour. Barriers designed to split or dam flows will slow flow advance, but cause the flow to widen, whereas oblique barriers can effectively divert flows, but may also accelerate flow advance. We argue that to be successful, mitigation of lava-flow hazards must incorporate the dynamics of lava flow–obstacle interactions into barrier design. The same generalizations apply to the effect of natural topographic features on flow geometry and advance rates.

Needle path planning and steering in a three-dimensional non-static environment using two-dimensional ultrasound images

PubMed Central

Vrooijink, Gustaaf J.; Abayazid, Momen; Patil, Sachin; Alterovitz, Ron; Misra, Sarthak

2015-01-01

Needle insertion is commonly performed in minimally invasive medical procedures such as biopsy and radiation cancer treatment. During such procedures, accurate needle tip placement is critical for correct diagnosis or successful treatment. Accurate placement of the needle tip inside tissue is challenging, especially when the target moves and anatomical obstacles must be avoided. We develop a needle steering system capable of autonomously and accurately guiding a steerable needle using two-dimensional (2D) ultrasound images. The needle is steered to a moving target while avoiding moving obstacles in a three-dimensional (3D) non-static environment. Using a 2D ultrasound imaging device, our system accurately tracks the needle tip motion in 3D space in order to estimate the tip pose. The needle tip pose is used by a rapidly exploring random tree-based motion planner to compute a feasible needle path to the target. The motion planner is sufficiently fast such that replanning can be performed repeatedly in a closed-loop manner. This enables the system to correct for perturbations in needle motion, and movement in obstacle and target locations. Our needle steering experiments in a soft-tissue phantom achieves maximum targeting errors of 0.86 ± 0.35 mm (without obstacles) and 2.16 ± 0.88 mm (with a moving obstacle). PMID:26279600

Optimal path planning for a mobile robot using cuckoo search algorithm

NASA Astrophysics Data System (ADS)

Mohanty, Prases K.; Parhi, Dayal R.

2016-03-01

The shortest/optimal path planning is essential for efficient operation of autonomous vehicles. In this article, a new nature-inspired meta-heuristic algorithm has been applied for mobile robot path planning in an unknown or partially known environment populated by a variety of static obstacles. This meta-heuristic algorithm is based on the levy flight behaviour and brood parasitic behaviour of cuckoos. A new objective function has been formulated between the robots and the target and obstacles, which satisfied the conditions of obstacle avoidance and target-seeking behaviour of robots present in the terrain. Depending upon the objective function value of each nest (cuckoo) in the swarm, the robot avoids obstacles and proceeds towards the target. The smooth optimal trajectory is framed with this algorithm when the robot reaches its goal. Some simulation and experimental results are presented at the end of the paper to show the effectiveness of the proposed navigational controller.

Analytical Approach to Target Detection and Localization at High-Frequency Bands Using Multipath Propagation

DTIC Science & Technology

2016-04-25

unseen directly by the antennas (both transmitter TX and receiver RX), or out of the Light- Of-Sight ( LOS ) area, as being covered by the obstacles such as...or in other words, out of the Light-Of-Sight ( LOS ) area, as being covered by the obstacles such as walls or buildings. This analysis is verified...that, we put a 1.5m high metallic wall at the distance of 1.5m from the two antennas. It is obviously that the Light Of Sight ( LOS ) is at 2.25m far

Accessing Geospatial Services in Limited Bandwidth Service-Oriented Architecture (SOA) Environments

ERIC Educational Resources Information Center

Boggs, James D.

2013-01-01

First responders are continuously moving at an incident site and this movement requires them to access Service-Oriented Architecture services, such as a Web Map Service, via mobile wireless networks. First responders from inside a building often have problems in communicating to devices outside that building due to propagation obstacles. Dynamic…

Does practicing a wide range of joint angle configurations lead to higher flexibility in a manual obstacle-avoidance target-pointing task?

PubMed Central

Bootsma, Reinoud J.; Schoemaker, Marina M.; Otten, Egbert; Mouton, Leonora J.; Bongers, Raoul M.

2017-01-01

Flexibility in motor actions can be defined as variability in the use of degrees of freedom (e.g., joint angles in the arm) over repetitions while keeping performance (e.g., fingertip position) stabilized. We examined whether flexibility can be increased through enlarging the joint angle range during practice in a manual obstacle-avoidance target-pointing task. To establish differences in flexibility we partitioned the variability in joint angles over repetitions in variability within (GEV) and variability outside the solution space (NGEV). More GEV than NGEV reflects flexibility; when the ratio of the GEV and NGEV is higher, flexibility is higher. The pretest and posttest consisted of 30 repetitions of manual pointing to a target while moving over a 10 cm high obstacle. To enlarge the joint angle range during practice participants performed 600 target-pointing movements while moving over obstacles of different heights (5–9 cm, 11–15 cm). The results indicated that practicing movements over obstacles of different heights led participants to use enlarged range of joint angles compared to the range of joint angles used in movements over the 10 cm obstacle in the pretest. However, for each individual obstacle neither joint angle variance nor flexibility were higher during practice. We also did not find more flexibility after practice. In the posttest, joint angle variance was in fact smaller than before practice, primarily in GEV. The potential influences of learning effects and the task used that could underlie the results obtained are discussed. We conclude that with this specific type of practice in this specific task, enlarging the range of joint angles does not lead to more flexibility. PMID:28700695

Stochastic, goal-oriented rapid impact modeling of uncertainty and environmental impacts in poorly-sampled sites using ex-situ priors

NASA Astrophysics Data System (ADS)

Li, Xiaojun; Li, Yandong; Chang, Ching-Fu; Tan, Benjamin; Chen, Ziyang; Sege, Jon; Wang, Changhong; Rubin, Yoram

2018-01-01

Modeling of uncertainty associated with subsurface dynamics has long been a major research topic. Its significance is widely recognized for real-life applications. Despite the huge effort invested in the area, major obstacles still remain on the way from theory and applications. Particularly problematic here is the confusion between modeling uncertainty and modeling spatial variability, which translates into a (mis)conception, in fact an inconsistency, in that it suggests that modeling of uncertainty and modeling of spatial variability are equivalent, and as such, requiring a lot of data. This paper investigates this challenge against the backdrop of a 7 km, deep underground tunnel in China, where environmental impacts are of major concern. We approach the data challenge by pursuing a new concept for Rapid Impact Modeling (RIM), which bypasses altogether the need to estimate posterior distributions of model parameters, focusing instead on detailed stochastic modeling of impacts, conditional to all information available, including prior, ex-situ information and in-situ measurements as well. A foundational element of RIM is the construction of informative priors for target parameters using ex-situ data, relying on ensembles of well-documented sites, pre-screened for geological and hydrological similarity to the target site. The ensembles are built around two sets of similarity criteria: a physically-based set of criteria and an additional set covering epistemic criteria. In another variation to common Bayesian practice, we update the priors to obtain conditional distributions of the target (environmental impact) dependent variables and not the hydrological variables. This recognizes that goal-oriented site characterization is in many cases more useful in applications compared to parameter-oriented characterization.

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

Evaluation of Learning Environments for Object-Oriented Programming: Measuring Cognitive Load with a Novel Measurement Technique

ERIC Educational Resources Information Center

Uysal, Murat Pasa

2016-01-01

Various methods and tools have been proposed to overcome the learning obstacles for Object-Oriented Programming (OOP). However, it remains difficult especially for novice learners. The problem may be not only adopting an instructional method, but also an Integrated Development Environment (IDE). Learners employ IDEs as a means to solve programming…

Interaction of vestibular, echolocation, and visual modalities guiding flight by the big brown bat, Eptesicus fuscus.

PubMed

Horowitz, Seth S; Cheney, Cheryl A; Simmons, James A

2004-01-01

The big brown bat (Eptesicus fuscus) is an aerial-feeding insectivorous species that relies on echolocation to avoid obstacles and to detect flying insects. Spatial perception in the dark using echolocation challenges the vestibular system to function without substantial visual input for orientation. IR thermal video recordings show the complexity of bat flights in the field and suggest a highly dynamic role for the vestibular system in orientation and flight control. To examine this role, we carried out laboratory studies of flight behavior under illuminated and dark conditions in both static and rotating obstacle tests while administering heavy water (D2O) to impair vestibular inputs. Eptesicus carried out complex maneuvers through both fixed arrays of wires and a rotating obstacle array using both vision and echolocation, or when guided by echolocation alone. When treated with D2O in combination with lack of visual cues, bats showed considerable decrements in performance. These data indicate that big brown bats use both vision and echolocation to provide spatial registration for head position information generated by the vestibular system.

Plant root and shoot dynamics during subsurface obstacle interaction

NASA Astrophysics Data System (ADS)

Conn, Nathaniel; Aguilar, Jeffrey; Benfey, Philip; Goldman, Daniel

As roots grow, they must navigate complex underground environments to anchor and retrieve water and nutrients. From gravity sensing at the root tip to pressure sensing along the tip and elongation zone, the complex mechanosensory feedback system of the root allows it to bend towards greater depths and avoid obstacles of high impedance by asymmetrically suppressing cell elongation. Here we investigate the mechanical and physiological responses of roots to rigid obstacles. We grow Maize, Zea mays, plants in quasi-2D glass containers (22cm x 17cm x 1.4cm) filled with photoelastic gel and observe that, regardless of obstacle interaction, smaller roots branch off the primary root when the upward growing shoot (which contains the first leaf) reaches an average length of 40 mm, coinciding with when the first leaf emerges. However, prior to branching, contacts with obstacles result in reduced root growth rates. The growth rate of the root relative to the shoot is sensitive to the angle of the obstacle surface, whereby the relative root growth is greatest for horizontally oriented surfaces. We posit that root growth is prioritized when horizontal obstacles are encountered to ensure anchoring and access to nutrients during later stages of development. NSF Physics of Living Systems.

UAV formation control design with obstacle avoidance in dynamic three-dimensional environment.

PubMed

Chang, Kai; Xia, Yuanqing; Huang, Kaoli

2016-01-01

This paper considers the artificial potential field method combined with rotational vectors for a general problem of multi-unmanned aerial vehicle (UAV) systems tracking a moving target in dynamic three-dimensional environment. An attractive potential field is generated between the leader and the target. It drives the leader to track the target based on the relative position of them. The other UAVs in the formation are controlled to follow the leader by the attractive control force. The repulsive force affects among the UAVs to avoid collisions and distribute the UAVs evenly on the spherical surface whose center is the leader-UAV. Specific orders or positions of the UAVs are not required. The trajectories of avoidance obstacle can be obtained through two kinds of potential field with rotation vectors. Every UAV can choose the optimal trajectory to avoid the obstacle and reconfigure the formation after passing the obstacle. Simulations study on UAV are presented to demonstrate the effectiveness of proposed method.

Target oriented dimensionality reduction of hyperspectral data by Kernel Fukunaga-Koontz Transform

NASA Astrophysics Data System (ADS)

Binol, Hamidullah; Ochilov, Shuhrat; Alam, Mohammad S.; Bal, Abdullah

2017-02-01

Principal component analysis (PCA) is a popular technique in remote sensing for dimensionality reduction. While PCA is suitable for data compression, it is not necessarily an optimal technique for feature extraction, particularly when the features are exploited in supervised learning applications (Cheriyadat and Bruce, 2003) [1]. Preserving features belonging to the target is very crucial to the performance of target detection/recognition techniques. Fukunaga-Koontz Transform (FKT) based supervised band reduction technique can be used to provide this requirement. FKT achieves feature selection by transforming into a new space in where feature classes have complimentary eigenvectors. Analysis of these eigenvectors under two classes, target and background clutter, can be utilized for target oriented band reduction since each basis functions best represent target class while carrying least information of the background class. By selecting few eigenvectors which are the most relevant to the target class, dimension of hyperspectral data can be reduced and thus, it presents significant advantages for near real time target detection applications. The nonlinear properties of the data can be extracted by kernel approach which provides better target features. Thus, we propose constructing kernel FKT (KFKT) to present target oriented band reduction. The performance of the proposed KFKT based target oriented dimensionality reduction algorithm has been tested employing two real-world hyperspectral data and results have been reported consequently.

Assistive peripheral phosphene arrays deliver advantages in obstacle avoidance in simulated end-stage retinitis pigmentosa: a virtual-reality study

NASA Astrophysics Data System (ADS)

Zapf, Marc Patrick H.; Boon, Mei-Ying; Lovell, Nigel H.; Suaning, Gregg J.

2016-04-01

Objective. The prospective efficacy of peripheral retinal prostheses for guiding orientation and mobility in the absence of residual vision, as compared to an implant for the central visual field (VF), was evaluated using simulated prosthetic vision (SPV). Approach. Sighted volunteers wearing a head-mounted display performed an obstacle circumvention task under SPV. Mobility and orientation performance with three layouts of prosthetic vision were compared: peripheral prosthetic vision of higher visual acuity (VA) but limited VF, of wider VF but limited VA, as well as centrally restricted prosthetic vision. Learning curves using these layouts were compared fitting an exponential model to the mobility and orientation measures. Main results. Using peripheral layouts, performance was superior to the central layout. Walking speed with both higher-acuity and wider-angle layouts was 5.6% higher, and mobility errors reduced by 46.4% and 48.6%, respectively, as compared to the central layout. The wider-angle layout yielded the least number of collisions, 63% less than the higher-acuity and 73% less than the central layout. Using peripheral layouts, the number of visual-scanning related head movements was 54.3% (higher-acuity) and 60.7% (wider-angle) lower, as compared to the central layout, and the ratio of time standing versus time walking was 51.9% and 61.5% lower, respectively. Learning curves did not differ between layouts, except for time standing versus time walking, where both peripheral layouts achieved significantly lower asymptotic values compared to the central layout. Significance. Beyond complementing residual vision for an improved performance, peripheral prosthetic vision can effectively guide mobility in the later stages of retinitis pigmentosa (RP) without residual vision. Further, the temporal dynamics of learning peripheral and central prosthetic vision are similar. Therefore, development of a peripheral retinal prosthesis and early implantation to alleviate VF constriction in RP should be considered to extend the target group and the time of benefit for potential retinal prosthesis implantees.

Genetic counseling/consultation in South-East Asia: a report from the workshop at the 10th Asia pacific conference on human genetics.

PubMed

Zayts, Olga; Sarangi, Srikant; Thong, Meow-Keong; Chung, Brian Hon-yin; Lo, Ivan Fao-man; Kan, Anita Sik-yau; Lee, Juliana Mei-har; Padilla, Carmencita David; Cutiongco-de la Paz, Eva Maria; Faradz, Sultana M H; Wasant, Pornswan

2013-12-01

This paper reports on the workshop 'Genetic Counseling/Consultations in South-East Asia' at the 10(th) Asia Pacific Conference on Human Genetics in Kuala Lumpur, Malaysia, in December 2012. The workshop brought together professionals and language/communication scholars from South-East Asia, and the UK. The workshop aimed at addressing culture- and context-specific genetic counseling/consultation practices in South-East Asia. As a way of contextualizing genetic counseling/consultation in South-East Asia, we first offer an overview of communication-oriented research generally, drawing attention to consultation and counseling as part of a communicative continuum with distinctive interactional features. We then provide examples of genetic counseling/consultation research in Hong Kong. As other countries in South-East Asia have not yet embarked on communication-oriented empirical research, we report on the current practices of genetic counseling/consultation in these countries in order to identify similarities and differences as well as key obstacles that could be addressed through future research. Three issues emerged as 'problematic': language, religion and culture. We suggest that communication-oriented research can provide a starting point for evidence-based reflections on how to incorporate a counseling mentality in genetic consultation. To conclude, we discuss the need for creating a platform for targeted training of genetic counselors based on communication-oriented research findings.

Integrating obstacle avoidance, global path planning, visual cue detection, and landmark triangulation in a mobile robot

NASA Astrophysics Data System (ADS)

Kortenkamp, David; Huber, Marcus J.; Congdon, Clare B.; Huffman, Scott B.; Bidlack, Clint R.; Cohen, Charles J.; Koss, Frank V.; Raschke, Ulrich; Weymouth, Terry E.

1993-05-01

This paper describes the design and implementation of an integrated system for combining obstacle avoidance, path planning, landmark detection and position triangulation. Such an integrated system allows the robot to move from place to place in an environment, avoiding obstacles and planning its way out of traps, while maintaining its position and orientation using distinctive landmarks. The task the robot performs is to search a 22 m X 22 m arena for 10 distinctive objects, visiting each object in turn. This same task was recently performed by a dozen different robots at a competition in which the robot described in this paper finished first.

Cortical neurons of bats respond best to echoes from nearest targets when listening to natural biosonar multi-echo streams.

PubMed

Beetz, M Jerome; Hechavarría, Julio C; Kössl, Manfred

2016-10-27

Bats orientate in darkness by listening to echoes from their biosonar calls, a behaviour known as echolocation. Recent studies showed that cortical neurons respond in a highly selective manner when stimulated with natural echolocation sequences that contain echoes from single targets. However, it remains unknown how cortical neurons process echolocation sequences containing echo information from multiple objects. In the present study, we used echolocation sequences containing echoes from three, two or one object separated in the space depth as stimuli to study neuronal activity in the bat auditory cortex. Neuronal activity was recorded with multi-electrode arrays placed in the dorsal auditory cortex, where neurons tuned to target-distance are found. Our results show that target-distance encoding neurons are mostly selective to echoes coming from the closest object, and that the representation of echo information from distant objects is selectively suppressed. This suppression extends over a large part of the dorsal auditory cortex and may override possible parallel processing of multiple objects. The presented data suggest that global cortical suppression might establish a cortical "default mode" that allows selectively focusing on close obstacle even without active attention from the animals.

Cortical neurons of bats respond best to echoes from nearest targets when listening to natural biosonar multi-echo streams

PubMed Central

Beetz, M. Jerome; Hechavarría, Julio C.; Kössl, Manfred

2016-01-01

Bats orientate in darkness by listening to echoes from their biosonar calls, a behaviour known as echolocation. Recent studies showed that cortical neurons respond in a highly selective manner when stimulated with natural echolocation sequences that contain echoes from single targets. However, it remains unknown how cortical neurons process echolocation sequences containing echo information from multiple objects. In the present study, we used echolocation sequences containing echoes from three, two or one object separated in the space depth as stimuli to study neuronal activity in the bat auditory cortex. Neuronal activity was recorded with multi-electrode arrays placed in the dorsal auditory cortex, where neurons tuned to target-distance are found. Our results show that target-distance encoding neurons are mostly selective to echoes coming from the closest object, and that the representation of echo information from distant objects is selectively suppressed. This suppression extends over a large part of the dorsal auditory cortex and may override possible parallel processing of multiple objects. The presented data suggest that global cortical suppression might establish a cortical “default mode” that allows selectively focusing on close obstacle even without active attention from the animals. PMID:27786252

Multi-AUV Target Search Based on Bioinspired Neurodynamics Model in 3-D Underwater Environments.

PubMed

Cao, Xiang; Zhu, Daqi; Yang, Simon X

2016-11-01

Target search in 3-D underwater environments is a challenge in multiple autonomous underwater vehicles (multi-AUVs) exploration. This paper focuses on an effective strategy for multi-AUV target search in the 3-D underwater environments with obstacles. First, the Dempster-Shafer theory of evidence is applied to extract information of environment from the sonar data to build a grid map of the underwater environments. Second, a topologically organized bioinspired neurodynamics model based on the grid map is constructed to represent the dynamic environment. The target globally attracts the AUVs through the dynamic neural activity landscape of the model, while the obstacles locally push the AUVs away to avoid collision. Finally, the AUVs plan their search path to the targets autonomously by a steepest gradient descent rule. The proposed algorithm deals with various situations, such as static targets search, dynamic targets search, and one or several AUVs break down in the 3-D underwater environments with obstacles. The simulation results show that the proposed algorithm is capable of guiding multi-AUV to achieve search task of multiple targets with higher efficiency and adaptability compared with other algorithms.

A Mobile Robot Sonar System with Obstacle Avoidance.

DTIC Science & Technology

1994-03-01

WITH OBSTACLE - AVOIDANCE __ by __ Patrick Gerard Byrne March 1994 Thesis Advisor : Yutaka Kanayama Approved for public release; distribution is...point p is on a line L whose normal has an orientation a and whose distance from the origin is r (Figure 5). This method has an advantage in expressing...sonar(FRONTR); Wine(&pl); while(hitl I >’- 100.0 11 hitl 1 - 0.0 ){ hitl I = sonar(FRONTR); I skipO; line(&p3); gat- robO (&posit 1); while(positl.x

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

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.

A semi-automated image analysis procedure for in situ plankton imaging systems.

PubMed

Bi, Hongsheng; Guo, Zhenhua; Benfield, Mark C; Fan, Chunlei; Ford, Michael; Shahrestani, Suzan; Sieracki, Jeffery M

2015-01-01

Plankton imaging systems are capable of providing fine-scale observations that enhance our understanding of key physical and biological processes. However, processing the large volumes of data collected by imaging systems remains a major obstacle for their employment, and existing approaches are designed either for images acquired under laboratory controlled conditions or within clear waters. In the present study, we developed a semi-automated approach to analyze plankton taxa from images acquired by the ZOOplankton VISualization (ZOOVIS) system within turbid estuarine waters, in Chesapeake Bay. When compared to images under laboratory controlled conditions or clear waters, images from highly turbid waters are often of relatively low quality and more variable, due to the large amount of objects and nonlinear illumination within each image. We first customized a segmentation procedure to locate objects within each image and extracted them for classification. A maximally stable extremal regions algorithm was applied to segment large gelatinous zooplankton and an adaptive threshold approach was developed to segment small organisms, such as copepods. Unlike the existing approaches for images acquired from laboratory, controlled conditions or clear waters, the target objects are often the majority class, and the classification can be treated as a multi-class classification problem. We customized a two-level hierarchical classification procedure using support vector machines to classify the target objects (< 5%), and remove the non-target objects (> 95%). First, histograms of oriented gradients feature descriptors were constructed for the segmented objects. In the first step all non-target and target objects were classified into different groups: arrow-like, copepod-like, and gelatinous zooplankton. Each object was passed to a group-specific classifier to remove most non-target objects. After the object was classified, an expert or non-expert then manually removed the non-target objects that could not be removed by the procedure. The procedure was tested on 89,419 images collected in Chesapeake Bay, and results were consistent with visual counts with >80% accuracy for all three groups.

A Semi-Automated Image Analysis Procedure for In Situ Plankton Imaging Systems

PubMed Central

Bi, Hongsheng; Guo, Zhenhua; Benfield, Mark C.; Fan, Chunlei; Ford, Michael; Shahrestani, Suzan; Sieracki, Jeffery M.

2015-01-01

Plankton imaging systems are capable of providing fine-scale observations that enhance our understanding of key physical and biological processes. However, processing the large volumes of data collected by imaging systems remains a major obstacle for their employment, and existing approaches are designed either for images acquired under laboratory controlled conditions or within clear waters. In the present study, we developed a semi-automated approach to analyze plankton taxa from images acquired by the ZOOplankton VISualization (ZOOVIS) system within turbid estuarine waters, in Chesapeake Bay. When compared to images under laboratory controlled conditions or clear waters, images from highly turbid waters are often of relatively low quality and more variable, due to the large amount of objects and nonlinear illumination within each image. We first customized a segmentation procedure to locate objects within each image and extracted them for classification. A maximally stable extremal regions algorithm was applied to segment large gelatinous zooplankton and an adaptive threshold approach was developed to segment small organisms, such as copepods. Unlike the existing approaches for images acquired from laboratory, controlled conditions or clear waters, the target objects are often the majority class, and the classification can be treated as a multi-class classification problem. We customized a two-level hierarchical classification procedure using support vector machines to classify the target objects (< 5%), and remove the non-target objects (> 95%). First, histograms of oriented gradients feature descriptors were constructed for the segmented objects. In the first step all non-target and target objects were classified into different groups: arrow-like, copepod-like, and gelatinous zooplankton. Each object was passed to a group-specific classifier to remove most non-target objects. After the object was classified, an expert or non-expert then manually removed the non-target objects that could not be removed by the procedure. The procedure was tested on 89,419 images collected in Chesapeake Bay, and results were consistent with visual counts with >80% accuracy for all three groups. PMID:26010260

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.

An Analysis of Group-Oriented Contingencies and Associated Side Effects in Preschool Children

ERIC Educational Resources Information Center

Payne, Steven W.; Dozier, Claudia L.; Briggs, Adam M.; Newquist, Matthew H.

2017-01-01

Group-oriented contingencies are arranged to target the behavior of a group of people simultaneously. Overall, group-oriented contingencies have been shown to be effective in both decreasing problem behavior and increasing appropriate behavior. However, results are mixed regarding which type(s) of group-oriented contingency is most effective for…

Optimal path planning for video-guided smart munitions via multitarget tracking

NASA Astrophysics Data System (ADS)

Borkowski, Jeffrey M.; Vasquez, Juan R.

2006-05-01

An advent in the development of smart munitions entails autonomously modifying target selection during flight in order to maximize the value of the target being destroyed. A unique guidance law can be constructed that exploits both attribute and kinematic data obtained from an onboard video sensor. An optimal path planning algorithm has been developed with the goals of obstacle avoidance and maximizing the value of the target impacted by the munition. Target identification and classification provides a basis for target value which is used in conjunction with multi-target tracks to determine an optimal waypoint for the munition. A dynamically feasible trajectory is computed to provide constraints on the waypoint selection. Results demonstrate the ability of the autonomous system to avoid moving obstacles and revise target selection in flight.

A sub-target approach to the kinodynamic motion control of a wheeled mobile robot

NASA Astrophysics Data System (ADS)

Motonaka, Kimiko; Watanabe, Keigo; Maeyama, Shoichi

2018-02-01

A mobile robot with two independently driven wheels is popular, but it is difficult to stabilize it by a continuous controller with a constant gain, due to its nonholonomic property. It is guaranteed that a nonholonomic controlled object can always be converged to an arbitrary point using a switching control method or a quasi-continuous control method based on an invariant manifold in a chained form. From this, the authors already proposed a kinodynamic controller to converge the states of such a two-wheeled mobile robot to the arbitrary target position while avoiding obstacles, by combining the control based on the invariant manifold and the harmonic potential field (HPF). On the other hand, it was confirmed in the previous research that there is a case that the robot cannot avoid the obstacle because there is no enough space to converge the current state to the target state. In this paper, we propose a method that divides the final target position into some sub-target positions and moves the robot step by step, and it is confirmed by the simulation that the robot can converge to the target position while avoiding obstacles using the proposed method.

Gas turbine system simulation: An object-oriented approach

NASA Technical Reports Server (NTRS)

Drummond, Colin K.; Follen, Gregory J.; Putt, Charles W.

1993-01-01

A prototype gas turbine engine simulation has been developed that offers a generalized framework for the simulation of engines subject to steady-state and transient operating conditions. The prototype is in preliminary form, but it successfully demonstrates the viability of an object-oriented approach for generalized simulation applications. Although object oriented programming languages are-relative to FORTRAN-somewhat austere, it is proposed that gas turbine simulations of an interdisciplinary nature will benefit significantly in terms of code reliability, maintainability, and manageability. This report elucidates specific gas turbine simulation obstacles that an object-oriented framework can overcome and describes the opportunity for interdisciplinary simulation that the approach offers.

Depletion forces on circular and elliptical obstacles induced by active matter

NASA Astrophysics Data System (ADS)

Leite, L. R.; Lucena, D.; Potiguar, F. Q.; Ferreira, W. P.

2016-12-01

Depletion forces exerted by self-propelled particles on circular and elliptical passive objects are studied using numerical simulations. We show that a bath of active particles can induce repulsive and attractive forces which are sensitive to the shape and orientation of the passive objects (either horizontal or vertical ellipses). The resultant force on the passive objects due to the active particles is studied as a function of the shape and orientation of the passive objects, magnitude of the angular noise, and distance between the passive objects. By increasing the distance between obstacles the magnitude of the repulsive depletion force increases, as long as such a distance is less than one active particle diameter. For longer distances, the magnitude of the force always decreases with increasing distance. We also found that attractive forces may arise for vertical ellipses at high enough area fraction.

Ravens, Corvus corax, follow gaze direction of humans around obstacles.

PubMed Central

Bugnyar, Thomas; Stöwe, Mareike; Heinrich, Bernd

2004-01-01

The ability to follow gaze (i.e. head and eye direction) has recently been shown for social mammals, particularly primates. In most studies, individuals could use gaze direction as a behavioural cue without understanding that the view of others may be different from their own. Here, we show that hand-raised ravens not only visually co-orient with the look-ups of a human experimenter but also reposition themselves to follow the experimenter's gaze around a visual barrier. Birds were capable of visual co-orientation already as fledglings but consistently tracked gaze direction behind obstacles not before six months of age. These results raise the possibility that sub-adult and adult ravens can project a line of sight for the other person into the distance. To what extent ravens may attribute mental significance to the visual behaviour of others is discussed. PMID:15306330

Depletion forces on circular and elliptical obstacles induced by active matter.

PubMed

Leite, L R; Lucena, D; Potiguar, F Q; Ferreira, W P

2016-12-01

Depletion forces exerted by self-propelled particles on circular and elliptical passive objects are studied using numerical simulations. We show that a bath of active particles can induce repulsive and attractive forces which are sensitive to the shape and orientation of the passive objects (either horizontal or vertical ellipses). The resultant force on the passive objects due to the active particles is studied as a function of the shape and orientation of the passive objects, magnitude of the angular noise, and distance between the passive objects. By increasing the distance between obstacles the magnitude of the repulsive depletion force increases, as long as such a distance is less than one active particle diameter. For longer distances, the magnitude of the force always decreases with increasing distance. We also found that attractive forces may arise for vertical ellipses at high enough area fraction.

Managing Systemic Curriculum Change: A Critical Analysis of Hong Kong's Target-Oriented Curriculum Initiative.

ERIC Educational Resources Information Center

Carless, David

1997-01-01

Describes Hong Kong's Target-Oriented Curriculum (TOC), a major curriculum renewal initiative designed to improve the quality of learning in local primary schools. Discusses the context in which it was introduced and factors that proved problematic in managing change. Focuses on five elements in the change process: practicality, ownership, teacher…

Bi-stability in cooperative transport by ants in the presence of obstacles

PubMed Central

Pinkoviezky, Itai; Feinerman, Ofer

2018-01-01

To cooperatively carry large food items to the nest, individual ants conform their efforts and coordinate their motion. Throughout this expedition, collective motion is driven both by internal interactions between the carrying ants and a response to newly arrived informed ants that orient the cargo towards the nest. During the transport process, the carrying group must overcome obstacles that block their path to the nest. Here, we investigate the dynamics of cooperative transport, when the motion of the ants is frustrated by a linear obstacle that obstructs the motion of the cargo. The obstacle contains a narrow opening that serves as the only available passage to the nest, and through which single ants can pass but not with the cargo. We provide an analytical model for the ant-cargo system in the constrained environment that predicts a bi-stable dynamic behavior between an oscillatory mode of motion along the obstacle and a convergent mode of motion near the opening. Using both experiments and simulations, we show how for small cargo sizes, the system exhibits spontaneous transitions between these two modes of motion due to fluctuations in the applied force on the cargo. The bi-stability provides two possible problem solving strategies for overcoming the obstacle, either by attempting to pass through the opening, or take large excursions to circumvent the obstacle. PMID:29746457

Bi-stability in cooperative transport by ants in the presence of obstacles.

PubMed

Ron, Jonathan E; Pinkoviezky, Itai; Fonio, Ehud; Feinerman, Ofer; Gov, Nir S

2018-05-01

To cooperatively carry large food items to the nest, individual ants conform their efforts and coordinate their motion. Throughout this expedition, collective motion is driven both by internal interactions between the carrying ants and a response to newly arrived informed ants that orient the cargo towards the nest. During the transport process, the carrying group must overcome obstacles that block their path to the nest. Here, we investigate the dynamics of cooperative transport, when the motion of the ants is frustrated by a linear obstacle that obstructs the motion of the cargo. The obstacle contains a narrow opening that serves as the only available passage to the nest, and through which single ants can pass but not with the cargo. We provide an analytical model for the ant-cargo system in the constrained environment that predicts a bi-stable dynamic behavior between an oscillatory mode of motion along the obstacle and a convergent mode of motion near the opening. Using both experiments and simulations, we show how for small cargo sizes, the system exhibits spontaneous transitions between these two modes of motion due to fluctuations in the applied force on the cargo. The bi-stability provides two possible problem solving strategies for overcoming the obstacle, either by attempting to pass through the opening, or take large excursions to circumvent the obstacle.

A biologically inspired neural net for trajectory formation and obstacle avoidance.

PubMed

Glasius, R; Komoda, A; Gielen, S C

1996-06-01

In this paper we present a biologically inspired two-layered neural network for trajectory formation and obstacle avoidance. The two topographically ordered neural maps consist of analog neurons having continuous dynamics. The first layer, the sensory map, receives sensory information and builds up an activity pattern which contains the optimal solution (i.e. shortest path without collisions) for any given set of current position, target positions and obstacle positions. Targets and obstacles are allowed to move, in which case the activity pattern in the sensory map will change accordingly. The time evolution of the neural activity in the second layer, the motor map, results in a moving cluster of activity, which can be interpreted as a population vector. Through the feedforward connections between the two layers, input of the sensory map directs the movement of the cluster along the optimal path from the current position of the cluster to the target position. The smooth trajectory is the result of the intrinsic dynamics of the network only. No supervisor is required. The output of the motor map can be used for direct control of an autonomous system in a cluttered environment or for control of the actuators of a biological limb or robot manipulator. The system is able to reach a target even in the presence of an external perturbation. Computer simulations of a point robot and a multi-joint manipulator illustrate the theory.

Measurement of functional capacity requirements of police officers to aid in development of an occupation-specific cardiac rehabilitation training program.

PubMed

Adams, Jenny; Schneider, Jonna; Hubbard, Matthew; McCullough-Shock, Tiffany; Cheng, Dunlei; Simms, Kay; Hartman, Julie; Hinton, Paul; Strauss, Danielle

2010-01-01

This study was designed to measure the functional capacity of healthy subjects during strenuous simulated police tasks, with the goal of developing occupation-specific training for cardiac rehabilitation of police officers. A calibrated metabolic instrument and an oxygen consumption data collection mask were used to measure the oxygen consumption and heart rates of 30 Dallas Police Academy officers and cadets as they completed an 8-event obstacle course that simulated chasing, subduing, and handcuffing a suspect. Standard target heart rates (85% of age-predicted maximum heart rate, or 0.85 x [220 - age]) and metabolic equivalents (METs) were calculated; a matched-sample t test based on differences between target and achieved heart rate and MET level was used for statistical analysis. Peak heart rates during the obstacle course simulation were significantly higher than the standard target heart rates (those at which treadmill stress tests in physicians' offices are typically stopped) (t(29) = 12.81, P < 0.001) and significantly higher than the suggested maximum of 150 beats/min during cardiac rehabilitation training (t(29) = 17.84, P < 0.001). Peak MET levels during the obstacle course simulation were also significantly higher than the goal level (8 METs) that patients typically achieve in a cardiac rehabilitation program (t(29) = 14.73, P < 0.001). We conclude that police work requires a functional capacity greater than that typically attained in traditional cardiac rehabilitation programs. Rehabilitation professionals should consider performing maximal stress tests and increasing the intensity of cardiac rehabilitation workouts to effectively train police officers who have had a cardiac event.

Achievements and future path of Tehran municipality in urban health domain: An Iranian experience

PubMed Central

Damari, Behzad; Riazi-Isfahani, Sahand

2016-01-01

Background: According to national laws and world experiences; provision, maintenance, and improving citizens’ health are considered to be the essential functions of municipalities as a "social institute". In order to equitably promote health conditions at urban level, particularly in marginal areas, since 2004 targeted efforts have been implemented in the municipality of Tehran metropolis. This study was intended to identify and analyze these targeted measures and tries to analyze health interventions in a conceptual framework and propose a future path. Methods: This is a qualitative study with content analysis approach. Reviewing documents and structured interviews with national health policy making and planning experts and executive managers of 22-region municipalities of Tehran metropolis were used to collect data. The data were analyzed on the basis of conceptual framework prepared for urban health in 4 domains including municipal interventions, goal achievements, drivers and obstacles of success, and the way forward. Results: From the viewpoint of interviewees, these new health actions of Tehran municipality are more based on public participation and the municipality was able to prioritize health issue in the programs and policies of Tehran city council. Tehran municipality has accomplished three types of interventions to improve health, which in orders of magnitude are: facilitative, promotional, and mandatory interventions. Development and institutionalization of public participation is the greatest achievement in health-oriented actions; and expansion of environmental and physical health-oriented facilities and promoting a healthy lifestyle are next in ranks. Conclusion: Since management alterations seriously challenges institutionalization of actions and innovations especially in the developing countries, it is suggested that mayors of metropolitan cities like Tehran document and review municipal health measures as soon as possible and while eliminating overlapping of interventions with other sectors, design and approve the charter of "health promoting municipality". The most important role of municipalities in this charter would be coordinating health improvement of citizens. This charter, when approved as a national policy could be used for other cities too. PMID:27390693

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.

Steering of an automated vehicle in an unstructured environment

NASA Astrophysics Data System (ADS)

Kanakaraju, Sampath; Shanmugasundaram, Sathish K.; Thyagarajan, Ramesh; Hall, Ernest L.

1999-08-01

The purpose of this paper is to describe a high-level path planning logic, which processes the data from a vision system and an ultrasonic obstacle avoidance system and steers an autonomous mobile robot between obstacles. The test bed was an autonomous root built at University of Cincinnati, and this logic was tested and debugged on this machine. Attempts have already been made to incorporate fuzzy system on a similar robot, and this paper extends them to take advantage of the robot's ZTR capability. Using the integrated vision syste, the vehicle senses its location and orientation. A rotating ultrasonic sensor is used to map the location and size of possible obstacles. With these inputs the fuzzy logic controls the speed and the steering decisions of the robot. With the incorporation of this logic, it has been observed that Bearcat II has been very successful in avoiding obstacles very well. This was achieved in the Ground Robotics Competition conducted by the AUVS in June 1999, where it travelled a distance of 154 feet in a 10ft. wide path ridden with obstacles. This logic proved to be a significant contributing factor in this feat of Bearcat II.

Flowing Dunes of Shangri-La Denoised

NASA Image and Video Library

2016-09-07

This radar image of the Shangri-La Sand Sea on Titan from NASA's Cassini spacecraft shows hundreds of sand dunes are visible as dark lines snaking across the surface. These dunes display patterns of undulation and divergence around elevated mountains (which appear bright to the radar), thereby showing the direction of wind and sand transport on the surface. Sands being carried from left to right (west to east) cannot surmount the tallest obstacles; instead, they are directed through chutes and canyons between the tall features, evident in thin, blade-like, isolated dunes between bright some features. Once sands have passed around the obstacles, they resume their downwind course, at first collecting into small, patchy dunes and then organizing into larger, more pervasive linear forms, before being halted once again by obstacles. These patterns reveal the effects not only of wind -- perhaps even modern winds if the dunes are actively moving today -- but also the effects of underlying bedrock and surrounding topography. Dunes across the solar system aid in our understanding of underlying topography, winds and climate, past and present. Similar patterns can be seen in dunes of the Great Sandy Desert in Australia, where dunes undulate broadly across the uneven terrain and are halted at the margins of sand-trapping lakes. The dune orientations correlate generally with the direction of current trade winds, and reveal that winds must have been similar back when the dunes formed, during the Pleistocene glacial and interglacial periods. The image was taken by the Cassini Synthetic Aperture radar (SAR) on July 25, 2016 during the mission's 122nd targeted Titan encounter. The image has been modified by the denoising method described in A. Lucas, JGR:Planets (2014). http://photojournal.jpl.nasa.gov/catalog/PIA20711

[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.

Robot-Assisted Needle Steering

PubMed Central

Reed, Kyle B.; Majewicz, Ann; Kallem, Vinutha; Alterovitz, Ron; Goldberg, Ken; Cowan, Noah J.; Okamura, Allison M.

2012-01-01

Needle insertion is a critical aspect of many medical treatments, diagnostic methods, and scientific studies, and is considered to be one of the simplest and most minimally invasive medical procedures. Robot-assisted needle steering has the potential to improve the effectiveness of existing medical procedures and enable new ones by allowing increased accuracy through more dexterous control of the needle tip path and acquisition of targets not accessible by straight-line trajectories. In this article, we describe a robot-assisted needle steering system that uses three integrated controllers: a motion planner concerned with guiding the needle around obstacles to a target in a desired plane, a planar controller that maintains the needle in the desired plane, and a torsion compensator that controls the needle tip orientation about the axis of the needle shaft. Experimental results from steering an asymmetric-tip needle in artificial tissue demonstrate the effectiveness of the system and its sensitivity to various environmental and control parameters. In addition, we show an example of needle steering in ex vivo biological tissue to accomplish a clinically relevant task, and highlight challenges of practical needle steering implementation. PMID:23028210

Optimal motion planning using navigation measure

NASA Astrophysics Data System (ADS)

Vaidya, Umesh

2018-05-01

We introduce navigation measure as a new tool to solve the motion planning problem in the presence of static obstacles. Existence of navigation measure guarantees collision-free convergence at the final destination set beginning with almost every initial condition with respect to the Lebesgue measure. Navigation measure can be viewed as a dual to the navigation function. While the navigation function has its minimum at the final destination set and peaks at the obstacle set, navigation measure takes the maximum value at the destination set and is zero at the obstacle set. A linear programming formalism is proposed for the construction of navigation measure. Set-oriented numerical methods are utilised to obtain finite dimensional approximation of this navigation measure. Application of the proposed navigation measure-based theoretical and computational framework is demonstrated for a motion planning problem in a complex fluid flow.

A kinematic analysis of the Space Station remote manipulator system (SSRMS)

NASA Technical Reports Server (NTRS)

Crane, Carl D., III; Duffy, Joseph; Carnahan, Tim

1991-01-01

An efficient reverse analysis of three 6-degree-of-freedom (dof) subchains of the 7-dof SSRMS is presented. The first subchain is formed by locking the seventh joint. The second subchain is formed by locking the second joint, while the third subchain is formed by locking the first joint (the grounded joint is counted as the first joint in the chain). There are a maximum of eight different arm configurations in each of the three subchains, and these were determined by employing a computer-efficient algorithm, which required the rooting of only at most quadratic polynomials. The algorithms were implemented, and the SSRMS was employed in an animated environment to perform and practice a number of useful tasks for Space Station servicing. The locking of the second joint has the advantage in that an operator can choose the orientation of the plane that contains the two longest links so as to avoid collisions with obstacles. However, it has the disadvantage that when the second joint angle equals 0 deg or 180 deg, the manipulator is in a singularity configuration. This plane can also be oriented by specifying the first joint angle, so that the plane can be oriented arbitrarily and, in this, the singularity is avoided.

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.

Particle Filtering for Obstacle Tracking in UAS Sense and Avoid Applications

PubMed Central

Moccia, Antonio

2014-01-01

Obstacle detection and tracking is a key function for UAS sense and avoid applications. In fact, obstacles in the flight path must be detected and tracked in an accurate and timely manner in order to execute a collision avoidance maneuver in case of collision threat. The most important parameter for the assessment of a collision risk is the Distance at Closest Point of Approach, that is, the predicted minimum distance between own aircraft and intruder for assigned current position and speed. Since assessed methodologies can cause some loss of accuracy due to nonlinearities, advanced filtering methodologies, such as particle filters, can provide more accurate estimates of the target state in case of nonlinear problems, thus improving system performance in terms of collision risk estimation. The paper focuses on algorithm development and performance evaluation for an obstacle tracking system based on a particle filter. The particle filter algorithm was tested in off-line simulations based on data gathered during flight tests. In particular, radar-based tracking was considered in order to evaluate the impact of particle filtering in a single sensor framework. The analysis shows some accuracy improvements in the estimation of Distance at Closest Point of Approach, thus reducing the delay in collision detection. PMID:25105154

Toward a theory of discontinuous career transition: investigating career transitions necessitated by traumatic life events.

PubMed

Haynie, J Michael; Shepherd, Dean

2011-05-01

Career researchers have focused on the mechanisms related to career progression. Although less studied, situations in which traumatic life events necessitate a discontinuous career transition are becoming increasingly prevalent. Employing a multiple case study method, we offer a deeper understanding of such transitions by studying an extreme case: soldiers and Marines disabled by wartime combat. Our study highlights obstacles to future employment that are counterintuitive and stem from the discontinuous and traumatic nature of job loss. Effective management of this type of transitioning appears to stem from efforts positioned to formulate a coherent narrative of the traumatic experience and thus to reconstruct foundational assumptions about the world, humanity, and self. These foundational assumptions form the basis for enacting future-orientated career strategies, such that progress toward establishing a new career path is greatest for those who can orientate themselves away from the past (trauma), away from the present (obstacles to a new career), and toward an envisioned future career positioned to confer meaning and purpose through work.

Robotic follow system and method

DOEpatents

Bruemmer, David J [Idaho Falls, ID; Anderson, Matthew O [Idaho Falls, ID

2007-05-01

Robot platforms, methods, and computer media are disclosed. The robot platform includes perceptors, locomotors, and a system controller, which executes instructions for a robot to follow a target in its environment. The method includes receiving a target bearing and sensing whether the robot is blocked front. If the robot is blocked in front, then the robot's motion is adjusted to avoid the nearest obstacle in front. If the robot is not blocked in front, then the method senses whether the robot is blocked toward the target bearing and if so, sets the rotational direction opposite from the target bearing, and adjusts the rotational velocity and translational velocity. If the robot is not blocked toward the target bearing, then the rotational velocity is adjusted proportional to an angle of the target bearing and the translational velocity is adjusted proportional to a distance to the nearest obstacle in front.

UAVs Task and Motion Planning in the Presence of Obstacles and Prioritized Targets

PubMed Central

Gottlieb, Yoav; Shima, Tal

2015-01-01

The intertwined task assignment and motion planning problem of assigning a team of fixed-winged unmanned aerial vehicles to a set of prioritized targets in an environment with obstacles is addressed. It is assumed that the targets’ locations and initial priorities are determined using a network of unattended ground sensors used to detect potential threats at restricted zones. The targets are characterized by a time-varying level of importance, and timing constraints must be fulfilled before a vehicle is allowed to visit a specific target. It is assumed that the vehicles are carrying body-fixed sensors and, thus, are required to approach a designated target while flying straight and level. The fixed-winged aerial vehicles are modeled as Dubins vehicles, i.e., having a constant speed and a minimum turning radius constraint. The investigated integrated problem of task assignment and motion planning is posed in the form of a decision tree, and two search algorithms are proposed: an exhaustive algorithm that improves over run time and provides the minimum cost solution, encoded in the tree, and a greedy algorithm that provides a quick feasible solution. To satisfy the target’s visitation timing constraint, a path elongation motion planning algorithm amidst obstacles is provided. Using simulations, the performance of the algorithms is compared, evaluated and exemplified. PMID:26610522

Needle Steering in 3-D Via Rapid Replanning

PubMed Central

Patil, Sachin; Burgner, Jessica; Webster, Robert J.; Alterovitz, Ron

2014-01-01

Steerable needles have the potential to improve the effectiveness of needle-based clinical procedures such as biopsy and drug delivery by improving targeting accuracy and reaching previously inaccessible targets that are behind sensitive or impenetrable anatomical regions. We present a new needle steering system capable of automatically reaching targets in 3-D environments while avoiding obstacles and compensating for real-world uncertainties. Given a specification of anatomical obstacles and a clinical target (e.g., from preoperative medical images), our system plans and controls needle motion in a closed-loop fashion under sensory feedback to optimize a clinical metric. We unify planning and control using a new fast algorithm that continuously replans the needle motion. Our rapid replanning approach is enabled by an efficient sampling-based rapidly exploring random tree (RRT) planner that achieves orders-of-magnitude reduction in computation time compared with prior 3-D approaches by incorporating variable curvature kinematics and a novel distance metric for planning. Our system uses an electromagnetic tracking system to sense the state of the needle tip during the procedure. We experimentally evaluate our needle steering system using tissue phantoms and animal tissue ex vivo. We demonstrate that our rapid replanning strategy successfully guides the needle around obstacles to desired 3-D targets with an average error of less than 3 mm. PMID:25435829

Grasp movement decoding from premotor and parietal cortex.

PubMed

Townsend, Benjamin R; Subasi, Erk; Scherberger, Hansjörg

2011-10-05

Despite recent advances in harnessing cortical motor-related activity to control computer cursors and robotic devices, the ability to decode and execute different grasping patterns remains a major obstacle. Here we demonstrate a simple Bayesian decoder for real-time classification of grip type and wrist orientation in macaque monkeys that uses higher-order planning signals from anterior intraparietal cortex (AIP) and ventral premotor cortex (area F5). Real-time decoding was based on multiunit signals, which had similar tuning properties to cells in previous single-unit recording studies. Maximum decoding accuracy for two grasp types (power and precision grip) and five wrist orientations was 63% (chance level, 10%). Analysis of decoder performance showed that grip type decoding was highly accurate (90.6%), with most errors occurring during orientation classification. In a subsequent off-line analysis, we found small but significant performance improvements (mean, 6.25 percentage points) when using an optimized spike-sorting method (superparamagnetic clustering). Furthermore, we observed significant differences in the contributions of F5 and AIP for grasp decoding, with F5 being better suited for classification of the grip type and AIP contributing more toward decoding of object orientation. However, optimum decoding performance was maximal when using neural activity simultaneously from both areas. Overall, these results highlight quantitative differences in the functional representation of grasp movements in AIP and F5 and represent a first step toward using these signals for developing functional neural interfaces for hand grasping.

Development and human factors analysis of an augmented reality interface for multi-robot tele-operation and control

NASA Astrophysics Data System (ADS)

Lee, Sam; Lucas, Nathan P.; Ellis, R. Darin; Pandya, Abhilash

2012-06-01

This paper presents a seamlessly controlled human multi-robot system comprised of ground and aerial robots of semiautonomous nature for source localization tasks. The system combines augmented reality interfaces capabilities with human supervisor's ability to control multiple robots. The role of this human multi-robot interface is to allow an operator to control groups of heterogeneous robots in real time in a collaborative manner. It used advanced path planning algorithms to ensure obstacles are avoided and that the operators are free for higher-level tasks. Each robot knows the environment and obstacles and can automatically generate a collision-free path to any user-selected target. It displayed sensor information from each individual robot directly on the robot in the video view. In addition, a sensor data fused AR view is displayed which helped the users pin point source information or help the operator with the goals of the mission. The paper studies a preliminary Human Factors evaluation of this system in which several interface conditions are tested for source detection tasks. Results show that the novel Augmented Reality multi-robot control (Point-and-Go and Path Planning) reduced mission completion times compared to the traditional joystick control for target detection missions. Usability tests and operator workload analysis are also investigated.

Obstacle-avoiding navigation system

DOEpatents

Borenstein, Johann; Koren, Yoram; Levine, Simon P.

1991-01-01

A system for guiding an autonomous or semi-autonomous vehicle through a field of operation having obstacles thereon to be avoided employs a memory for containing data which defines an array of grid cells which correspond to respective subfields in the field of operation of the vehicle. Each grid cell in the memory contains a value which is indicative of the likelihood, or probability, that an obstacle is present in the respectively associated subfield. The values in the grid cells are incremented individually in response to each scan of the subfields, and precomputation and use of a look-up table avoids complex trigonometric functions. A further array of grid cells is fixed with respect to the vehicle form a conceptual active window which overlies the incremented grid cells. Thus, when the cells in the active window overly grid cell having values which are indicative of the presence of obstacles, the value therein is used as a multiplier of the precomputed vectorial values. The resulting plurality of vectorial values are summed vectorially in one embodiment of the invention to produce a virtual composite repulsive vector which is then summed vectorially with a target-directed vector for producing a resultant vector for guiding the vehicle. In an alternative embodiment, a plurality of vectors surrounding the vehicle are computed, each having a value corresponding to obstacle density. In such an embodiment, target location information is used to select between alternative directions of travel having low associated obstacle densities.

Dual stage potential field method for robotic path planning

NASA Astrophysics Data System (ADS)

Singh, Pradyumna Kumar; Parida, Pramod Kumar

2018-04-01

Path planning for autonomous mobile robots are the root for all autonomous mobile systems. Various methods are used for optimization of path to be followed by the autonomous mobile robots. Artificial potential field based path planning method is one of the most used methods for the researchers. Various algorithms have been proposed using the potential field approach. But in most of the common problems are encounters while heading towards the goal or target. i.e. local minima problem, zero potential regions problem, complex shaped obstacles problem, target near obstacle problem. In this paper we provide a new algorithm in which two types of potential functions are used one after another. The former one is to use to get the probable points and later one for getting the optimum path. In this algorithm we consider only the static obstacle and goal.

Mission Specification and Control for Unmanned Aerial and Ground Vehicles for Indoor Target Discovery and Tracking

DTIC Science & Technology

2010-01-01

open garage leading to the building interior. The UAV is positioned north of a potential ingress to the building. As the mission begins, the UAV...camera, the difficulty in detecting and navigating around obstacles using this non- stereo camera necessitated a precomputed map of all obstacles and

Acoustic basis for recognition of aspect-dependent three-dimensional targets by an echolocating bottlenose dolphin.

PubMed

Helweg, D A; Au, W W; Roitblat, H L; Nachtigall, P E

1996-04-01

The relationships between acoustic features of target echoes and the cognitive representations of the target formed by an echolocating dolphin will influence the ease with which the dolphin can recognize a target. A blindfolded Atlantic bottlenose dolphin (Tursiops truncatus) learned to match aspect-dependent three-dimensional targets (such as a cube) at haphazard orientations, although with some difficulty. This task may have been difficult because aspect-dependent targets produce different echoes at different orientations, which required the dolphin to have some capability for object constancy across changes in echo characteristics. Significant target-related differences in echo amplitude, rms bandwidth, and distributions of interhighlight intervals were observed among echoes collected when the dolphin was performing the task. Targets could be classified using a combination of energy flux density and rms bandwidth by a linear discriminant analysis and a nearest centroid classifier. Neither statistical model could classify targets without amplitude information, but the highest accuracy required spectral information as well. This suggests that the dolphin recognized the targets using a multidimensional representation containing amplitude and spectral information and that dolphins can form stable representations of targets regardless of orientation based on varying sensory properties.

Zinc finger nuclease technology: advances and obstacles in modelling and treating genetic disorders.

PubMed

Jabalameli, Hamid Reza; Zahednasab, Hamid; Karimi-Moghaddam, Amin; Jabalameli, Mohammad Reza

2015-03-01

Zinc finger nucleases (ZFNs) are engineered restriction enzymes designed to target specific DNA sequences within the genome. Assembly of zinc finger DNA-binding domain to a DNA-cleavage domain enables the enzyme machinery to target unique locus in the genome and invoke endogenous DNA repair mechanisms. This machinery offers a versatile approach in allele editing and gene therapy. Here we discuss the architecture of ZFNs and strategies for generating targeted modifications within the genome. We review advances in gene therapy and modelling of the disease using these enzymes and finally, discuss the practical obstacles in using this technology. Copyright © 2014 Elsevier B.V. All rights reserved.

Path planning for mobile robot using the novel repulsive force algorithm

NASA Astrophysics Data System (ADS)

Sun, Siyue; Yin, Guoqiang; Li, Xueping

2018-01-01

A new type of repulsive force algorithm is proposed to solve the problem of local minimum and the target unreachable of the classic Artificial Potential Field (APF) method in this paper. The Gaussian function that is related to the distance between the robot and the target is added to the traditional repulsive force, solving the problem of the goal unreachable with the obstacle nearby; variable coefficient is added to the repulsive force component to resize the repulsive force, which can solve the local minimum problem when the robot, the obstacle and the target point are in the same line. The effectiveness of the algorithm is verified by simulation based on MATLAB and actual mobile robot platform.

Obstacle avoidance and concealed target detection using the Army Research Lab ultra-wideband synchronous impulse reconstruction (UWB SIRE) forward imaging radar

NASA Astrophysics Data System (ADS)

Nguyen, Lam; Wong, David; Ressler, Marc; Koenig, Francois; Stanton, Brian; Smith, Gregory; Sichina, Jeffrey; Kappra, Karl

2007-04-01

The U.S. Army Research Laboratory (ARL), as part of a mission and customer funded exploratory program, has developed a new low-frequency, ultra-wideband (UWB) synthetic aperture radar (SAR) for forward imaging to support the Army's vision of an autonomous navigation system for robotic ground vehicles. These unmanned vehicles, equipped with an array of imaging sensors, will be tasked to help detect man-made obstacles such as concealed targets, enemy minefields, and booby traps, as well as other natural obstacles such as ditches, and bodies of water. The ability of UWB radar technology to help detect concealed objects has been documented in the past and could provide an important obstacle avoidance capability for autonomous navigation systems, which would improve the speed and maneuverability of these vehicles and consequently increase the survivability of the U. S. forces on the battlefield. One of the primary features of the radar is the ability to collect and process data at combat pace in an affordable, compact, and lightweight package. To achieve this, the radar is based on the synchronous impulse reconstruction (SIRE) technique where several relatively slow and inexpensive analog-to-digital (A/D) converters are used to sample the wide bandwidth of the radar signals. We conducted an experiment this winter at Aberdeen Proving Ground (APG) to support the phenomenological studies of the backscatter from positive and negative obstacles for autonomous robotic vehicle navigation, as well as the detection of concealed targets of interest to the Army. In this paper, we briefly describe the UWB SIRE radar and the test setup in the experiment. We will also describe the signal processing and the forward imaging techniques used in the experiment. Finally, we will present imagery of man-made obstacles such as barriers, concertina wires, and mines.

Learning robotic eye-arm-hand coordination from human demonstration: a coupled dynamical systems approach.

PubMed

Lukic, Luka; Santos-Victor, José; Billard, Aude

2014-04-01

We investigate the role of obstacle avoidance in visually guided reaching and grasping movements. We report on a human study in which subjects performed prehensile motion with obstacle avoidance where the position of the obstacle was systematically varied across trials. These experiments suggest that reaching with obstacle avoidance is organized in a sequential manner, where the obstacle acts as an intermediary target. Furthermore, we demonstrate that the notion of workspace travelled by the hand is embedded explicitly in a forward planning scheme, which is actively involved in detecting obstacles on the way when performing reaching. We find that the gaze proactively coordinates the pattern of eye-arm motion during obstacle avoidance. This study provides also a quantitative assessment of the coupling between the eye-arm-hand motion. We show that the coupling follows regular phase dependencies and is unaltered during obstacle avoidance. These observations provide a basis for the design of a computational model. Our controller extends the coupled dynamical systems framework and provides fast and synchronous control of the eyes, the arm and the hand within a single and compact framework, mimicking similar control system found in humans. We validate our model for visuomotor control of a humanoid robot.

Cascading a systolic array and a feedforward neural network for navigation and obstacle avoidance using potential fields

NASA Technical Reports Server (NTRS)

Plumer, Edward S.

1991-01-01

A technique is developed for vehicle navigation and control in the presence of obstacles. A potential function was devised that peaks at the surface of obstacles and has its minimum at the proper vehicle destination. This function is computed using a systolic array and is guaranteed not to have local minima. A feedfoward neural network is then used to control the steering of the vehicle using local potential field information. In this case, the vehicle is a trailer truck backing up. Previous work has demonstrated the capability of a neural network to control steering of such a trailer truck backing to a loading platform, but without obstacles. Now, the neural network was able to learn to navigate a trailer truck around obstacles while backing toward its destination. The network is trained in an obstacle free space to follow the negative gradient of the field, after which the network is able to control and navigate the truck to its target destination in a space of obstacles which may be stationary or movable.

CytoSpectre: a tool for spectral analysis of oriented structures on cellular and subcellular levels.

PubMed

Kartasalo, Kimmo; Pölönen, Risto-Pekka; Ojala, Marisa; Rasku, Jyrki; Lekkala, Jukka; Aalto-Setälä, Katriina; Kallio, Pasi

2015-10-26

Orientation and the degree of isotropy are important in many biological systems such as the sarcomeres of cardiomyocytes and other fibrillar structures of the cytoskeleton. Image based analysis of such structures is often limited to qualitative evaluation by human experts, hampering the throughput, repeatability and reliability of the analyses. Software tools are not readily available for this purpose and the existing methods typically rely at least partly on manual operation. We developed CytoSpectre, an automated tool based on spectral analysis, allowing the quantification of orientation and also size distributions of structures in microscopy images. CytoSpectre utilizes the Fourier transform to estimate the power spectrum of an image and based on the spectrum, computes parameter values describing, among others, the mean orientation, isotropy and size of target structures. The analysis can be further tuned to focus on targets of particular size at cellular or subcellular scales. The software can be operated via a graphical user interface without any programming expertise. We analyzed the performance of CytoSpectre by extensive simulations using artificial images, by benchmarking against FibrilTool and by comparisons with manual measurements performed for real images by a panel of human experts. The software was found to be tolerant against noise and blurring and superior to FibrilTool when analyzing realistic targets with degraded image quality. The analysis of real images indicated general good agreement between computational and manual results while also revealing notable expert-to-expert variation. Moreover, the experiment showed that CytoSpectre can handle images obtained of different cell types using different microscopy techniques. Finally, we studied the effect of mechanical stretching on cardiomyocytes to demonstrate the software in an actual experiment and observed changes in cellular orientation in response to stretching. CytoSpectre, a versatile, easy-to-use software tool for spectral analysis of microscopy images was developed. The tool is compatible with most 2D images and can be used to analyze targets at different scales. We expect the tool to be useful in diverse applications dealing with structures whose orientation and size distributions are of interest. While designed for the biological field, the software could also be useful in non-biological applications.

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

Application of ant colony algorithm in path planning of the data center room robot

NASA Astrophysics Data System (ADS)

Wang, Yong; Ma, Jianming; Wang, Ying

2017-05-01

According to the Internet Data Center (IDC) room patrol robot as the background, the robot in the search path of autonomous obstacle avoidance and path planning ability, worked out in advance of the robot room patrol mission. The simulation experimental results show that the improved ant colony algorithm for IDC room patrol robot obstacle avoidance planning, makes the robot along an optimal or suboptimal and safe obstacle avoidance path to reach the target point to complete the task. To prove the feasibility of the method.

Autonomous Rover Traverse and Precise Arm Placement on Remotely Designated Targets

NASA Technical Reports Server (NTRS)

Nesnas, Issa A.; Pivtoraiko, Mihail N.; Kelly, Alonzo; Fleder, Michael

2012-01-01

This software controls a rover platform to traverse rocky terrain autonomously, plan paths, and avoid obstacles using its stereo hazard and navigation cameras. It does so while continuously tracking a target of interest selected from 10 20 m away. The rover drives and tracks the target until it reaches the vicinity of the target. The rover then positions itself to approach the target, deploys its robotic arm, and places the end effector instrument on the designated target to within 2-3-cm accuracy of the originally selected target. This software features continuous navigation in a fairly rocky field in an outdoor environment and the ability to enable the rover to avoid large rocks and traverse over smaller ones. Using point-and-click mouse commands, a scientist designates targets in the initial imagery acquired from the rover s mast cameras. The navigation software uses stereo imaging, traversability analysis, path planning, trajectory generation, and trajectory execution. It also includes visual target tracking of a designated target selected from 10 m away while continuously navigating the rocky terrain. Improvements in this design include steering while driving, which uses continuous curvature paths. There are also several improvements to the traversability analyzer, including improved data fusion of traversability maps that result from pose estimation uncertainties, dealing with boundary effects to enable tighter maneuvers, and handling a wider range of obstacles. This work advances what has been previously developed and integrated on the Mars Exploration Rovers by using algorithms that are capable of traversing more rock-dense terrains, enabling tight, thread-the-needle maneuvers. These algorithms were integrated on the newly refurbished Athena Mars research rover, and were fielded in the JPL Mars Yard. Forty-three runs were conducted with targets at distances ranging from 5 to 15 m, and a success rate of 93% was achieved for placement of the instrument within 2-3 cm of the target.

SU-E-T-133: Dosimetric Impact of Scan Orientation Relative to Target Motion During Spot Scanning Proton Therapy

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

Stoker, J; Summers, P; Li, X

2014-06-01

Purpose: This study seeks to evaluate the dosimetric effects of intra-fraction motion during spot scanning proton beam therapy as a function of beam-scan orientation and target motion amplitude. Method: Multiple 4DCT scans were collected of a dynamic anthropomorphic phantom mimicking respiration amplitudes of 0 (static), 0.5, 1.0, and 1.5 cm. A spot-scanning treatment plan was developed on the maximum intensity projection image set, using an inverse-planning approach. Dynamic phantom motion was continuous throughout treatment plan delivery.The target nodule was designed to accommodate film and thermoluminescent dosimeters (TLD). Film and TLDs were uniquely labeled by location within the target. The phantommore » was localized on the treatment table using the clinically available orthogonal kV on-board imaging device. Film inserts provided data for dose uniformity; TLDs provided a 3% precision estimate of absolute dose. An inhouse script was developed to modify the delivery order of the beam spots, to orient the scanning direction parallel or perpendicular to target motion.TLD detector characterization and analysis was performed by the Imaging and Radiation Oncology Core group (IROC)-Houston. Film inserts, exhibiting a spatial resolution of 1mm, were analyzed to determine dose homogeneity within the radiation target. Results: Parallel scanning and target motions exhibited reduced target dose heterogeneity, relative to perpendicular scanning orientation. The average percent deviation in absolute dose for the motion deliveries relative to the static delivery was 4.9±1.1% for parallel scanning, and 11.7±3.5% (p<<0.05) for perpendicularly oriented scanning. Individual delivery dose deviations were not necessarily correlated to amplitude of motion for either scan orientation. Conclusions: Results demonstrate a quantifiable difference in dose heterogeneity as a function of scan orientation, more so than target amplitude. Comparison to the analyzed planar dose of a single field hint that multiple-field delivery alters intra-fraction beam-target motion synchronization and may mitigate heterogeneity, though further study is warranted.« less

Sensorimotor and Cognitive Predictors of Impaired Gait Adaptability in Older People.

PubMed

Caetano, Maria Joana D; Menant, Jasmine C; Schoene, Daniel; Pelicioni, Paulo H S; Sturnieks, Daina L; Lord, Stephen R

2017-09-01

The ability to adapt gait when negotiating unexpected hazards is crucial to maintain stability and avoid falling. This study investigated whether impaired gait adaptability in a task including obstacle and stepping targets is associated with cognitive and sensorimotor capacities in older adults. Fifty healthy older adults (74±7 years) were instructed to either (a) avoid an obstacle at usual step distance or (b) step onto a target at either a short or long step distance projected on a walkway two heel strikes ahead and then continue walking. Participants also completed cognitive and sensorimotor function assessments. Stroop test and reaction time performance significantly discriminated between participants who did and did not make stepping errors, and poorer Trail-Making test performance predicted shorter penultimate step length in the obstacle avoidance condition. Slower reaction time predicted poorer stepping accuracy; increased postural sway, weaker quadriceps strength, and poorer Stroop and Trail-Making test performances predicted increased number of steps taken to approach the target/obstacle and shorter step length; and increased postural sway and higher concern about falling predicted slower step velocity. Superior executive function, fast processing speed, and good muscle strength and balance were all associated with successful gait adaptability. Processing speed appears particularly important for precise foot placements; cognitive capacity for step length adjustments; and early and/or additional cognitive processing involving the inhibition of a stepping pattern for obstacle avoidance. This information may facilitate fall risk assessments and fall prevention strategies. © The Author 2016. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Diversity-Oriented Synthesis as a Strategy for Fragment Evolution against GSK3β.

PubMed

Wang, Yikai; Wach, Jean-Yves; Sheehan, Patrick; Zhong, Cheng; Zhan, Chenyang; Harris, Richard; Almo, Steven C; Bishop, Joshua; Haggarty, Stephen J; Ramek, Alexander; Berry, Kayla N; O'Herin, Conor; Koehler, Angela N; Hung, Alvin W; Young, Damian W

2016-09-08

Traditional fragment-based drug discovery (FBDD) relies heavily on structural analysis of the hits bound to their targets. Herein, we present a complementary approach based on diversity-oriented synthesis (DOS). A DOS-based fragment collection was able to produce initial hit compounds against the target GSK3β, allow the systematic synthesis of related fragment analogues to explore fragment-level structure-activity relationship, and finally lead to the synthesis of a more potent compound.

LLNL Scientist is Passionate About Targets

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

Butlin, Becky

With a lifelong passion for problem-solving and a love of production, Becky Butlin has helped lead the National Ignition Facility Target Fabrication Team through obstacles and challenges for the past six years.

[Educational obstacles in the everyday living of the nurse teacher's pedagogical practice].

PubMed

Rodrigues, Malvina Thaís Pacheco; Mendes Sobrinho, José Augusto de Carvalho

2008-01-01

University teaching emerges as a theme frequently discussed in the educational scene. This article aims to investigate the educational obstacles emerging in the everyday living of the pedagogical practice of the nurse teacher from the Nursing Graduation Course at UEPSI, wishing to subsidize the elaboration of proposals for overcoming of these obstacles. It is a study of qualitative approach with data collection, questionnaire and semi-structured interview and data analysis through content analysis. According to the analysis, it is clear that the educational obstacles relate to the teacher person, to the students and to the institution. Thus, an establishment of a continuing education program in the action-reflection-action perspective is proposed as a way of overcoming the obstacles.

The influence of crustal magnetic sources on the topology of the Martian magnetic environment

NASA Astrophysics Data System (ADS)

Brain, David Andrew

2002-09-01

In this thesis I use magnetometer data and magnetic field models to explore the morphology of magnetic fields close to Mars, with emphasis on the manner and extent to which crustal magnetic sources affect the magnetic field configuration. I analyze Mars Global Surveyor (MGS) Magnetometer (MAG) data to determine the relative importance of the solar wind and of crustal magnetic sources in the observations. Crustal sources locally modify the solar wind interaction, adding variability to the Martian magnetic environment that depends on planetary rotation. I identify trends in the vector magnetic field with respect to altitude, solar zenith angle, and geographic location. The influence of the strongest crustal source extends to 1300 1400 km. I then use MAG data to evaluate models for the magnetic field associated with Mars' crust and for the solar wind interaction with the Martian ionosphere. A linear superposition of a spherical harmonic crustal model and a gasdynamic solar wind model improves the fit to MAG data over that from either model individually. I use simple pressure balance to calculate the shape and size of the Martian solar wind obstacle under a variety of different conditions. The obstacle is irregularly shaped (“lumpy”) and varies over the course of a Martian rotation, over a Martian year, and with changes in the upstream pressure. The obstacle above strong crustal sources can exceed 1000 km and is always higher than the altitude of the MGS spacecraft in its mapping orbit. I use a superposition model to explore the magnetic field topology at Mars under a variety of conditions. The model field topology is sensitive to changes in the interplanetary magnetic field (IMF) strength and orientation, as well as to Mars' orientation with respect to the solar wind flow. Regions of open magnetic field are located above strong crustal sources in the models, where the magnetic field is radially oriented with respect to the Martian surface. An examination of MAG and electron reflectometer (ER) data above one of these regions reveals a sharp change in the electron energy spectrum coinciding with perturbations in the orientation of the magnetic field.

A systematic analysis of the Braitenberg vehicle 2b for point-like stimulus sources.

PubMed

Rañó, Iñaki

2012-09-01

Braitenberg vehicles have been used experimentally for decades in robotics with limited empirical understanding. This paper presents the first mathematical model of the vehicle 2b, displaying so-called aggression behaviour, and analyses the possible trajectories for point-like smooth stimulus sources. This sensory-motor steering control mechanism is used to implement biologically grounded target approach, target-seeking or obstacle-avoidance behaviour. However, the analysis of the resulting model reveals that complex and unexpected trajectories can result even for point-like stimuli. We also prove how the implementation of the controller and the vehicle morphology interact to affect the behaviour of the vehicle. This work provides a better understanding of Braitenberg vehicle 2b, explains experimental results and paves the way for a formally grounded application on robotics as well as for a new way of understanding target seeking in biology.

Orientation tuning of contrast masking caused by motion streaks.

PubMed

Apthorp, Deborah; Cass, John; Alais, David

2010-08-01

We investigated whether the oriented trails of blur left by fast-moving dots (i.e., "motion streaks") effectively mask grating targets. Using a classic overlay masking paradigm, we varied mask contrast and target orientation to reveal underlying tuning. Fast-moving Gaussian blob arrays elevated thresholds for detection of static gratings, both monoptically and dichoptically. Monoptic masking at high mask (i.e., streak) contrasts is tuned for orientation and exhibits a similar bandwidth to masking functions obtained with grating stimuli (∼30 degrees). Dichoptic masking fails to show reliable orientation-tuned masking, but dichoptic masks at very low contrast produce a narrowly tuned facilitation (∼17 degrees). For iso-oriented streak masks and grating targets, we also explored masking as a function of mask contrast. Interestingly, dichoptic masking shows a classic "dipper"-like TVC function, whereas monoptic masking shows no dip and a steeper "handle". There is a very strong unoriented component to the masking, which we attribute to transiently biased temporal frequency masking. Fourier analysis of "motion streak" images shows interesting differences between dichoptic and monoptic functions and the information in the stimulus. Our data add weight to the growing body of evidence that the oriented blur of motion streaks contributes to the processing of fast motion signals.

Electrophysiological correlates of retrieval orientation in reality monitoring.

PubMed

Rosburg, Timm; Mecklinger, Axel; Johansson, Mikael

2011-02-14

Retrieval orientation describes the modulation in the processing of retrieval cues by the nature of the targeted material in memory. Retrieval orientation is usually investigated by analyzing the cortical responses to new (unstudied) material when different memory contents are targeted. This approach avoids confounding effects of retrieval success. We investigated the neural correlates of retrieval orientation in reality monitoring with event-related potentials (ERPs) and assessed the impact of retrieval accuracy on obtained ERP measures. Thirty-two subjects studied visually presented object names that were followed either by a picture of that object (perceived condition) or by the instruction to mentally generate such a picture (imagine condition). Subsequently, subjects had to identify object names of one study condition and reject object names of the second study condition together with newly presented object names. The data analysis showed that object names were more accurately identified when they had been presented in the perceived condition. Two topographically distinct ERP effects of retrieval orientation were revealed: From 600 to 1100 ms after stimulus representation, ERPs were more positive at frontal electrode sites when object names from the imagine condition were targeted. The analysis of response-locked ERP data revealed an additional effect at posterior electrode sites, with more negative ERPs shortly after response onset when items from the imagine condition were targeted. The ERP effect at frontal electrode sites, but not at posterior electrode sites was modulated by relative memory accuracy, with stronger effects in subjects who had lower memory accuracy for items of the imagine condition. The findings are suggestive for a contribution of frontal brain areas to retrieval orientation processes in reality monitoring and indicate that neural correlates of retrieval orientation can be modulated by retrieval effort, with stronger activation of these correlates with increasing task demands. Copyright © 2010 Elsevier Inc. All rights reserved.

Building clinicians-researchers partnerships: lessons from diverse natural settings and practice-oriented initiatives.

PubMed

Castonguay, Louis G; Youn, Soo Jeong; Xiao, Henry; Muran, J Christopher; Barber, Jacques P

2015-01-01

In this concluding paper, we identify the type of studies conducted by 11 teams of contributors to a special issue on building clinicians-researchers partnerships. Those studies were conducted across a variety of clinical settings. We also integrate the lessons that have emerged from their collaborative initiatives in terms of obstacles faced, strategies adopted to address these challenges, benefits gained, and general recommendations offered to facilitate studies conducted with or by clinicians. The paper ends with the authors' thoughts about the future success of practice-oriented research in general.

A Case Study of Curriculum Implementation in Hong Kong.

ERIC Educational Resources Information Center

Carless, David R.

1998-01-01

Describes and analyzes the perceptions and reactions of a well-qualified, positively oriented primary-school English teacher to Hong Kong's target-oriented curriculum (TOC) initiative, a major government-sponsored innovation. The analysis encompasses teacher attitudes, teacher training and support, teachers' understanding of an innovation, teacher…

"How We Stay Together Without Going Crazy:" Reconstruction of Reality Among Women of Mixed-Orientation Relationships.

PubMed

Adler, Adir; Ben-Ari, Adital

2018-01-01

Until recently, the literature that addressed the phenomenon of mixed-orientation relationships, in which the female partner is straight and the male partner is non-straight, has focused mainly on the men's perspective. Most of the studies have employed a pessimistic tone, underscoring the obstacles faced by each of the partners. This study was designed to understand how women of mixed-orientation relationships construct their reality within such a relationship, focusing on elements that assist them in maintaining those relationships. Based on the phenomenological paradigm, in-depth interviews with eight women in mixed-orientation relationships were conducted. The findings indicate that in order to adapt to their newly constructed reality, women reframe various individual, marital, and social aspects in their lives. Those reframing processes constituted a point of departure to developing a conceptual model, which outlines the journey to reality reconstruction among women in mixed-orientation relationships.

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.

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.

Diversity-Oriented Synthesis as a Strategy for Fragment Evolution against GSK3β

PubMed Central

2016-01-01

Traditional fragment-based drug discovery (FBDD) relies heavily on structural analysis of the hits bound to their targets. Herein, we present a complementary approach based on diversity-oriented synthesis (DOS). A DOS-based fragment collection was able to produce initial hit compounds against the target GSK3β, allow the systematic synthesis of related fragment analogues to explore fragment-level structure–activity relationship, and finally lead to the synthesis of a more potent compound. PMID:27660690

Pre-service mathematics teachers' attitudes towards learning English: A case study in Yogyakarta

NASA Astrophysics Data System (ADS)

Setyaningrum, Wahyu

2017-08-01

This study investigated attitudes of pre-service mathematics teachers towards English as one of the subject at the university. It is a qualitative study in which questionnaire and face-to-face interview were employed to collect the data. The participants of this study were sixty students of mathematics education department at one of the university in Yogyakarta. The main research question was concern with how pre-service mathematics teachers perceive the importance of learning English. This study found that most of the participants perceive English as an important language that should be acquired by mathematics teachers. Their beliefs about the importance of English were mostly due to instrumental orientation rather than integrative orientation, such as getting a good job, getting a scholarship and understanding learning sources that are written in English. The data also revealed some obstacles faced by pre-service mathematics teachers in learning English as an additional language for them. The main obstacles were related to the differences between English for mathematics and English in daily life including its vocabulary and structure. Most of the participants argued that several mathematics vocabularies had precise meaning and different from daily English. In addition, they found difficult to understand some sentences used in the paper journal due to its structure. This study therefore, provided an insight into the pre-service mathematics teachers' perception and obstacles when learning English that could be use in improving pre-service teachers' education.

Passive RFID Rotation Dimension Reduction via Aggregation

NASA Astrophysics Data System (ADS)

Matthews, Eric

Radio Frequency IDentification (RFID) has applications in object identification, position, and orientation tracking. RFID technology can be applied in hospitals for patient and equipment tracking, stores and warehouses for product tracking, robots for self-localisation, tracking hazardous materials, or locating any other desired object. Efficient and accurate algorithms that perform localisation are required to extract meaningful data beyond simple identification. A Received Signal Strength Indicator (RSSI) is the strength of a received radio frequency signal used to localise passive and active RFID tags. Many factors affect RSSI such as reflections, tag rotation in 3D space, and obstacles blocking line-of-sight. LANDMARC is a statistical method for estimating tag location based on a target tag's similarity to surrounding reference tags. LANDMARC does not take into account the rotation of the target tag. By either aggregating multiple reference tag positions at various rotations, or by determining a rotation value for a newly read tag, we can perform an expected value calculation based on a comparison to the k-most similar training samples via an algorithm called K-Nearest Neighbours (KNN) more accurately. By choosing the average as the aggregation function, we improve the relative accuracy of single-rotation LANDMARC localisation by 10%, and any-rotation localisation by 20%.

WIMP detection and slow ion dynamics in carbon nanotube arrays.

PubMed

Cavoto, G; Cirillo, E N M; Cocina, F; Ferretti, J; Polosa, A D

2016-01-01

Large arrays of aligned carbon nanotubes (CNTs), open at one end, could be used as target material for the directional detection of weakly interacting dark matter particles (WIMPs). As a result of a WIMP elastic scattering on a CNT, a carbon ion might be injected in the body of the array and propagate through multiple collisions within the lattice. The ion may eventually emerge from the surface with open end CNTs, provided that its longitudinal momentum is large enough to compensate energy losses and its transverse momentum approaches the channeling conditions in a single CNT. Therefore, the angle formed between the WIMP wind apparent orientation and the direction of parallel carbon nanotube axes must be properly chosen. We focus on very low ion recoil kinetic energies, related to low mass WIMPs ([Formula: see text] GeV) where most of the existing experiments have low sensitivity. Relying on some exact results on two-dimensional lattices of circular obstacles, we study the low energy ion motion in the transverse plane with respect to CNT directions. New constraints are obtained on how to devise the CNT arrays to maximize the target channeling efficiency.

Shifting Priorities: Reflections on Teaching Qualitative Research Methods

ERIC Educational Resources Information Center

Booker, Keonya C.

2009-01-01

The purpose of this paper is to describe pedagogical approaches to qualitative methodology by an instructor of educational psychology at a large research university. The essay begins with an overview of how my graduate training influenced my orientation to empirical study. Next, I will focus on the obstacles encountered when instructing graduate…

The Barriers to Achieving the Wider Goals of General Education and Their Implications for the British Educational Research Association.

ERIC Educational Resources Information Center

Raven, John

1990-01-01

Advocates revamping the British educational system from technical-rational content model to student-centered process programs designed to promote critical thinking, individual initiative, and communication skills. Discusses obstacles to this educational reform, emphasizing research orientation. Urges the British Educational Research Association to…

The QUASAR Project: The "Revolution of the Possible" in Mathematics Instructional Reform in Urban Middle Schools.

ERIC Educational Resources Information Center

Silver, Edward A.; Stein, Mary Kay

1996-01-01

Examines critical features of the QUASAR Project, a mathematics instruction program oriented toward helping students develop a meaningful understanding of mathematical ideas through challenging mathematical tasks, and discusses findings regarding the positive impact it has had on students. Challenges and obstacles in implementing the project are…

Meta-Action Research with Pre-Service Teachers: A Case Study

ERIC Educational Resources Information Center

Villacañas de Castro, Luis Sebastián

2014-01-01

This article analyses a case of action research collaboratively conducted by a university teacher and 50 students in a master's course in teacher training. Its originality resides in the socio-economic, academic, and conceptual nature of the obstacles encountered in the module; in the meta-theoretical orientation of the action research that was…

Implementing Blended Learning at a Developing University: Obstacles in the Way

ERIC Educational Resources Information Center

Tshabalala, Mswazi; Ndeya-Ndereya, Charity; van der Merwe, Tiana

2014-01-01

Higher Education Institutions (HEIs) are striving to provide effective learning experiences to address the needs of the digitally-oriented generation of learners. Blended learning has emerged as a solution to address these needs and has been adopted by various HEIs. However, not all academic staff members adopt blended learning when it is…

Relationship-Enhancing Communication Skills in Prime-Time Family-Oriented Situation Comedies.

ERIC Educational Resources Information Center

Aust, Charles F.

Television situation comedies have been criticized for their portrayal of dysfunctional family behavior. An exploratory content analysis study assessed the extent of relationship-enhancing communication skills in family-oriented, prime-time situation comedies, a genre frequently targeted for both scorn and praise. Three episodes each of five shows…

Terrain mapping and control of unmanned aerial vehicles

NASA Astrophysics Data System (ADS)

Kang, Yeonsik

In this thesis, methods for terrain mapping and control of unmanned aerial vehicles (UAVs) are proposed. First, robust obstacle detection and tracking algorithm are introduced to eliminate the clutter noise uncorrelated with the real obstacle. This is an important problem since most types of sensor measurements are vulnerable to noise. In order to eliminate such noise, a Kalman filter-based interacting multiple model (IMM) algorithm is employed to effectively detect obstacles and estimate their positions precisely. Using the outcome of the IMM-based obstacle detection algorithm, a new method of building a probabilistic occupancy grid map is proposed based on Bayes rule in probability theory. Since the proposed map update law uses the outputs of the IMM-based obstacle detection algorithm, simultaneous tracking of moving targets and mapping of stationary obstacles are possible. This can be helpful especially in a noisy outdoor environment where different types of obstacles exist. Another feature of the algorithm is its capability to eliminate clutter noise as well as measurement noise. The proposed algorithm is simulated in Matlab using realistic sensor models. The results show close agreement with the layout of real obstacles. An efficient method called "quadtree" is used to process massive geographical information in a convenient manner. The algorithm is evaluated in a realistic simulation environment called RIPTIDE, which the NASA Ames Research Center developed to access the performance of complicated software for UAVs. Supposing that a UAV is equipped with abovementioned obstacle detection and mapping algorithm, the control problem of a small fixed-wing UAV is studied. A Nonlinear Model Predictive Control (NMPC is designed as a high level controller for the fixed-wing UAV using a kinematic model of the UAV. The kinematic model is employed because of the assumption that there exist low level controls on the UAV. The UAV dynamics are nonlinear with input constraints which is the main challenge explored in this thesis. The control objective of the NMPC is determined to track a desired line, and the analysis of the designed NMPC's stability is followed to find the conditions that can assure stability. Then, the control objective is extended to track adjoined multiple line segments with obstacle avoidance capability. In simulation, the performance of the NMPC is superb with fast convergence and small overshoot. The computation time is not a burden for a fixed-wing UAV controller with a Pentium level on-board computer that provides a reasonable control update rate.

An Empirical Analysis of Chinese College Learners' Obstacles to MOOC Learning in an English Context

ERIC Educational Resources Information Center

Liu, Liangxing

2017-01-01

This article reports a study applying an exploratory factor analysis to discovering the underlying factor structure of Chinese college students' obstacles to learning MOOC in an English context. Seven obstacle factors are identified: 1. academic and language skills; 2. internet skills; 3. course instruction/management; 4. learning motivations; 5.…

Fully automatic guidance and control for rotorcraft nap-of-the-Earth flight following planned profiles. Volume 1: Real-time piloted simulation

NASA Technical Reports Server (NTRS)

Clement, Warren F.; Gorder, Peter J.; Jewell, Wayne F.

1991-01-01

Developing a single-pilot, all-weather nap-of-the-earth (NOE) capability requires fully automatic NOE (ANOE) navigation and flight control. Innovative guidance and control concepts are investigated in a four-fold research effort that: (1) organizes the on-board computer-based storage and real-time updating of NOE terrain profiles and obstacles in course-oriented coordinates indexed to the mission flight plan; (2) defines a class of automatic anticipative pursuit guidance algorithms and necessary data preview requirements to follow the vertical, lateral, and longitudinal guidance commands dictated by the updated flight profiles; (3) automates a decision-making process for unexpected obstacle avoidance; and (4) provides several rapid response maneuvers. Acquired knowledge from the sensed environment is correlated with the forehand knowledge of the recorded environment (terrain, cultural features, threats, and targets), which is then used to determine an appropriate evasive maneuver if a nonconformity of the sensed and recorded environments is observed. This four-fold research effort was evaluated in both fixed-based and moving-based real-time piloted simulations, thereby, providing a practical demonstration for evaluating pilot acceptance of the automated concepts, supervisory override, manual operation, and re-engagement of the automatic system. Volume one describes the major components of the guidance and control laws as well as the results of the piloted simulations. Volume two describes the complete mathematical model of the fully automatic guidance system for rotorcraft NOE flight following planned flight profiles.

Fully Automatic Guidance and Control for Rotorcraft Nap-of-the-earth Flight Following Planned Profiles. Volume 2: Mathematical Model

NASA Technical Reports Server (NTRS)

Clement, Warren F.; Gorder, Peter J.; Jewell, Wayne F.

1991-01-01

Developing a single-pilot, all-weather nap-of-the-earth (NOE) capability requires fully automatic NOE (ANOE) navigation and flight control. Innovative guidance and control concepts are investigated in a four-fold research effort that: (1) organizes the on-board computer-based storage and real-time updating of NOE terrain profiles and obstacles in course-oriented coordinates indexed to the mission flight plan; (2) defines a class of automatic anticipative pursuit guidance algorithms and necessary data preview requirements to follow the vertical, lateral, and longitudinal guidance commands dictated by the updated flight profiles; (3) automates a decision-making process for unexpected obstacle avoidance; and (4) provides several rapid response maneuvers. Acquired knowledge from the sensed environment is correlated with the forehand knowledge of the recorded environment (terrain, cultural features, threats, and targets), which is then used to determine an appropriate evasive maneuver if a nonconformity of the sensed and recorded environments is observed. This four-fold research effort was evaluated in both fixed-base and moving-base real-time piloted simulations; thereby, providing a practical demonstration for evaluating pilot acceptance of the automated concepts, supervisory override, manual operation, and re-engagement of the automatic system. Volume one describes the major components of the guidance and control laws as well as the results of the piloted simulations. Volume two describes the complete mathematical model of the fully automatic guidance system for rotorcraft NOE flight following planned flight profiles.

INS integrated motion analysis for autonomous vehicle navigation

NASA Technical Reports Server (NTRS)

Roberts, Barry; Bazakos, Mike

1991-01-01

The use of inertial navigation system (INS) measurements to enhance the quality and robustness of motion analysis techniques used for obstacle detection is discussed with particular reference to autonomous vehicle navigation. The approach to obstacle detection used here employs motion analysis of imagery generated by a passive sensor. Motion analysis of imagery obtained during vehicle travel is used to generate range measurements to points within the field of view of the sensor, which can then be used to provide obstacle detection. Results obtained with an INS integrated motion analysis approach are reviewed.

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.

Context Oriented Information Integration

NASA Astrophysics Data System (ADS)

Mohania, Mukesh; Bhide, Manish; Roy, Prasan; Chakaravarthy, Venkatesan T.; Gupta, Himanshu

Faced with growing knowledge management needs, enterprises are increasingly realizing the importance of seamlessly integrating critical business information distributed across both structured and unstructured data sources. Academicians have focused on this problem but there still remain a lot of obstacles for its widespread use in practice. One of the key problems is the absence of schema in unstructured text. In this paper we present a new paradigm for integrating information which overcomes this problem - that of Context Oriented Information Integration. The goal is to integrate unstructured data with the structured data present in the enterprise and use the extracted information to generate actionable insights for the enterprise. We present two techniques which enable context oriented information integration and show how they can be used for solving real world problems.

The origins and evolutionary history of human non-coding RNA regulatory networks.

PubMed

Sherafatian, Masih; Mowla, Seyed Javad

2017-04-01

The evolutionary history and origin of the regulatory function of animal non-coding RNAs are not well understood. Lack of conservation of long non-coding RNAs and small sizes of microRNAs has been major obstacles in their phylogenetic analysis. In this study, we tried to shed more light on the evolution of ncRNA regulatory networks by changing our phylogenetic strategy to focus on the evolutionary pattern of their protein coding targets. We used available target databases of miRNAs and lncRNAs to find their protein coding targets in human. We were able to recognize evolutionary hallmarks of ncRNA targets by phylostratigraphic analysis. We found the conventional 3'-UTR and lesser known 5'-UTR targets of miRNAs to be enriched at three consecutive phylostrata. Firstly, in eukaryata phylostratum corresponding to the emergence of miRNAs, our study revealed that miRNA targets function primarily in cell cycle processes. Moreover, the same overrepresentation of the targets observed in the next two consecutive phylostrata, opisthokonta and eumetazoa, corresponded to the expansion periods of miRNAs in animals evolution. Coding sequence targets of miRNAs showed a delayed rise at opisthokonta phylostratum, compared to the 3' and 5' UTR targets of miRNAs. LncRNA regulatory network was the latest to evolve at eumetazoa.

The Effects of Shoe Traction and Obstacle Height on Lower Extremity Coordination Dynamics during Walking

PubMed Central

Decker, Leslie; Houser, Jeremy J.; Noble, John M.; Karst, Gregory M.; Stergiou, Nicholas

2009-01-01

This study aims to investigate the effects of shoe traction and obstacle height on lower extremity relative phase dynamics (analysis of intralimb coordination) during walking to better understand the mechanisms employed to avoid slippage following obstacle clearance. Ten participants walked at a self-selected pace during eight conditions: four obstacle heights (0%, 10%, 20%, and 40% of limb length) while wearing two pairs of shoes (low and high traction). A coordination analysis was used and phasing relationships between lower extremity segments were examined. The results demonstrated that significant behavioral changes were elicited under varied obstacle heights and frictional conditions. Both decreasing shoe traction and increasing obstacle height resulted in a more in-phase relationship between the interacting lower limb segments. The higher the obstacle and the lower the shoe traction, the more unstable the system became. These changes in phasing relationship and variability are indicators of alterations in coordinative behavior, which if pushed further may have lead to falling. PMID:19187929

Development of Multifunctional Fluorescent–Magnetic Nanoprobes for Selective Capturing and Multicolor Imaging of Heterogeneous Circulating Tumor Cells

PubMed Central

2016-01-01

Circulating tumor cells (CTC) are highly heterogeneous in nature due to epithelial–mesenchymal transition (EMT), which is the major obstacle for CTC analysis via “liquid biopsy”. This article reports the development of a new class of multifunctional fluorescent–magnetic multicolor nanoprobes for targeted capturing and accurate identification of heterogeneous CTC. A facile design approach for the synthesis and characterization of bioconjugated multifunctonal nanoprobes that exhibit excellent magnetic properties and emit very bright and photostable multicolor fluorescence at red, green, and blue under 380 nm excitation is reported. Experimental data presented show that the multifunctional multicolor nanoprobes can be used for targeted capture and multicolor fluorescence mapping of heterogeneous CTC and can distinguish targeted CTC from nontargeted cells. PMID:27255574

Through the eyes of a bird: modelling visually guided obstacle flight

PubMed Central

Lin, Huai-Ti; Ros, Ivo G.; Biewener, Andrew A.

2014-01-01

Various flight navigation strategies for birds have been identified at the large spatial scales of migratory and homing behaviours. However, relatively little is known about close-range obstacle negotiation through cluttered environments. To examine obstacle flight guidance, we tracked pigeons (Columba livia) flying through an artificial forest of vertical poles. Interestingly, pigeons adjusted their flight path only approximately 1.5 m from the forest entry, suggesting a reactive mode of path planning. Combining flight trajectories with obstacle pole positions, we reconstructed the visual experience of the pigeons throughout obstacle flights. Assuming proportional–derivative control with a constant delay, we searched the relevant parameter space of steering gains and visuomotor delays that best explained the observed steering. We found that a pigeon's steering resembles proportional control driven by the error angle between the flight direction and the desired opening, or gap, between obstacles. Using this pigeon steering controller, we simulated obstacle flights and showed that pigeons do not simply steer to the nearest opening in the direction of flight or destination. Pigeons bias their flight direction towards larger visual gaps when making fast steering decisions. The proposed behavioural modelling method converts the obstacle avoidance behaviour into a (piecewise) target-aiming behaviour, which is better defined and understood. This study demonstrates how such an approach decomposes open-loop free-flight behaviours into components that can be independently evaluated. PMID:24812052

Through the eyes of a bird: modelling visually guided obstacle flight.

PubMed

Lin, Huai-Ti; Ros, Ivo G; Biewener, Andrew A

2014-07-06

Various flight navigation strategies for birds have been identified at the large spatial scales of migratory and homing behaviours. However, relatively little is known about close-range obstacle negotiation through cluttered environments. To examine obstacle flight guidance, we tracked pigeons (Columba livia) flying through an artificial forest of vertical poles. Interestingly, pigeons adjusted their flight path only approximately 1.5 m from the forest entry, suggesting a reactive mode of path planning. Combining flight trajectories with obstacle pole positions, we reconstructed the visual experience of the pigeons throughout obstacle flights. Assuming proportional-derivative control with a constant delay, we searched the relevant parameter space of steering gains and visuomotor delays that best explained the observed steering. We found that a pigeon's steering resembles proportional control driven by the error angle between the flight direction and the desired opening, or gap, between obstacles. Using this pigeon steering controller, we simulated obstacle flights and showed that pigeons do not simply steer to the nearest opening in the direction of flight or destination. Pigeons bias their flight direction towards larger visual gaps when making fast steering decisions. The proposed behavioural modelling method converts the obstacle avoidance behaviour into a (piecewise) target-aiming behaviour, which is better defined and understood. This study demonstrates how such an approach decomposes open-loop free-flight behaviours into components that can be independently evaluated.

Multicamera polarized vision for the orientation with the skylight polarization patterns

NASA Astrophysics Data System (ADS)

Fan, Chen; Hu, Xiaoping; He, Xiaofeng; Zhang, Lilian; Wang, Yujie

2018-04-01

A robust orientation algorithm based on the skylight polarization patterns for the urban ground vehicle is presented. We present the orientation model with the Rayleigh scattering and propose the robust orientation algorithm with the total least square. The proposed algorithm can utilize the whole sky area polarization patterns for realizing a more robust and accurate orientation. To enhance the algorithm's robustness in the urban environment, we develop a real-time method that uses the gradient of the degree of the polarization to remove the obstacles in the polarization image. In addition, our algorithm can solve the ambiguity problem of the polarized orientation without any other sensors. We also conduct a static rotating and a dynamic car experiments to evaluate the algorithm. The results demonstrate that our proposed algorithm can provide an accurate orientation estimation for the ground vehicle in the open and urban environments-the root-mean-square error in the static experiment is 0.28 deg and in the dynamic experiment is 0.81 deg. Finally, we discuss insights gained with respect to further work in optics and robotics.

Random walk of passive tracers among randomly moving obstacles.

PubMed

Gori, Matteo; Donato, Irene; Floriani, Elena; Nardecchia, Ilaria; Pettini, Marco

2016-04-14

This study is mainly motivated by the need of understanding how the diffusion behavior of a biomolecule (or even of a larger object) is affected by other moving macromolecules, organelles, and so on, inside a living cell, whence the possibility of understanding whether or not a randomly walking biomolecule is also subject to a long-range force field driving it to its target. By means of the Continuous Time Random Walk (CTRW) technique the topic of random walk in random environment is here considered in the case of a passively diffusing particle among randomly moving and interacting obstacles. The relevant physical quantity which is worked out is the diffusion coefficient of the passive tracer which is computed as a function of the average inter-obstacles distance. The results reported here suggest that if a biomolecule, let us call it a test molecule, moves towards its target in the presence of other independently interacting molecules, its motion can be considerably slowed down.

Creating Optimal Learning Environments through Invitational Education: An Alternative to Control Oriented School Reform

ERIC Educational Resources Information Center

Fretz, Joan R.

2015-01-01

Understanding what motivates people to put forth effort, persevere in the face of obstacles, and choose their behaviors is key to creating an optimal learning environment--the type of school that policy makers desire, but are unknowingly sabotaging (Dweck, 2000). Many motivation and self-concept theories provide important insight with regard to…

Developing operation algorithms for vision subsystems in autonomous mobile robots

NASA Astrophysics Data System (ADS)

Shikhman, M. V.; Shidlovskiy, S. V.

2018-05-01

The paper analyzes algorithms for selecting keypoints on the image for the subsequent automatic detection of people and obstacles. The algorithm is based on the histogram of oriented gradients and the support vector method. The combination of these methods allows successful selection of dynamic and static objects. The algorithm can be applied in various autonomous mobile robots.

Evaluation of a Multicomponent, Behaviorally Oriented, Problem-Based "Summer School" Program for Adolescents with Diabetes.

ERIC Educational Resources Information Center

Schlundt, David G.; Flannery, Mary Ellen; Davis, Dianne L.; Kinzer, Charles K.; Pichert, James W.

1999-01-01

Examines a two-week summer program using problem-based learning and behavior therapy to help adolescents with insulin-dependent diabetes improve their ability to cope with obstacles to dietary management. Improvements were observed in self-efficacy, problem-solving skills, and self-reported coping strategies. No significant changes were observed…

Single-Cell RNA-Seq Reveals Transcriptional Heterogeneity in Latent and Reactivated HIV-Infected Cells.

PubMed

Golumbeanu, Monica; Cristinelli, Sara; Rato, Sylvie; Munoz, Miguel; Cavassini, Matthias; Beerenwinkel, Niko; Ciuffi, Angela

2018-04-24

Despite effective treatment, HIV can persist in latent reservoirs, which represent a major obstacle toward HIV eradication. Targeting and reactivating latent cells is challenging due to the heterogeneous nature of HIV-infected cells. Here, we used a primary model of HIV latency and single-cell RNA sequencing to characterize transcriptional heterogeneity during HIV latency and reactivation. Our analysis identified transcriptional programs leading to successful reactivation of HIV expression. Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.

Attitudes of Austrian Psychotherapists Towards Process and Outcome Monitoring.

PubMed

Kaiser, Tim; Schmutzhart, Lisa; Laireiter, Anton-Rupert

2018-03-08

While monitoring systems in psychotherapy have become more common, little is known about the attitudes that mental health practitioners have towards these systems. In an online survey among 111 Austrian psychotherapists and trainees, attitudes towards therapy monitoring were measured. A well-validated questionnaire measuring attitudes towards outcome monitoring, the Outcome Measurement Questionnaire, was used. Clinicians' theoretical orientations as well as previous knowledge and experience with monitoring systems were associated with positive attitudes towards monitoring. Possible factors that may have led to these findings, like the views of different theoretical orientations or obstacles in Austrian public health care, are discussed.

[Process-oriented quality management in the hospital].

PubMed

Wolters, H G

1998-03-01

Procedures and experiences concerning the implementation of quality management in a midsize hospital with 6 medical disciplines are described. Quality of infrastructure was checked with lists and the quality of medical performance assessed by means of standardized numerical audit with all professional groups. Weaknesses were identified by comparing the result to each quality indicator with target standards. As examples, causal relations and consequences of deficiencies in clinical care documentation, scheme of preoperative diagnosis, co-ordination of surgical procedures and handling of complications are given in more detail. Obstacles were rated depending on frequency and risk potential, sometimes cost effectiveness. Members of all professional groups and departments involved participated in trouble solving teams to which external expert assistance was provided. For example, interventions leading to improved co-ordination of surgical activities and their impacts are specified. Improving systematically the quality of clinical procedures is one gateway to establish quality management in hospitals continuously and thoroughly becoming an integrated part of the corporate culture. Investment of resources is necessary but justified by midrange benefits.

Description and status update on GELLO: a proposed standardized object-oriented expression language for clinical decision support.

PubMed

Sordo, Margarita; Boxwala, Aziz A; Ogunyemi, Omolola; Greenes, Robert A

2004-01-01

A major obstacle to sharing computable clinical knowledge is the lack of a common language for specifying expressions and criteria. Such a language could be used to specify decision criteria, formulae, and constraints on data and action. Al-though the Arden Syntax addresses this problem for clinical rules, its generalization to HL7's object-oriented data model is limited. The GELLO Expression language is an object-oriented language used for expressing logical conditions and computations in the GLIF3 (GuideLine Interchange Format, v. 3) guideline modeling language. It has been further developed under the auspices of the HL7 Clinical Decision Support Technical Committee, as a proposed HL7 standard., GELLO is based on the Object Constraint Language (OCL), because it is vendor-independent, object-oriented, and side-effect-free. GELLO expects an object-oriented data model. Although choice of model is arbitrary, standardization is facilitated by ensuring that the data model is compatible with the HL7 Reference Information Model (RIM).

Are family-oriented interventions in Portuguese genetics services a remote possibility? Professionals' views on a multifamily intervention for cancer susceptibility families.

PubMed

Mendes, Alvaro; Paneque, Milena; Sousa, Liliana

2012-10-01

This article examines genetics healthcare professionals' opinions about a multifamily psychoeducational programme for hereditary cancer susceptibility families, implemented at a Portuguese genetics service. Their views on how a family-oriented approach is envisioned to be incorporated in Portuguese genetic counselling services are also reported. Six focus groups and three individual interviews were undertaken comprising 30 professionals working in the provision of genetic counselling and genetic counsellor trainees. Participants were given a page-summary describing the intervention and asked to comment the strengths and limitations of the multifamily intervention. All interviews were fully transcribed and analysed using the constant comparison method. The qualitative analysis generated data comprising four thematic categories in relation to the professionals' views: (a) usefulness of the programme; (b) programme's methodological and practical obstacles; (c) genetics services constraints; and (d) suggestions for improving the programme and further family-oriented interventions. We reflect on the reported views examining the intervention, and on how current constraints of genetic services limit the provision of psychosocial support for cancer susceptibility families. The implications of these findings regarding the purpose of genetic counselling are discussed. Results may sensitise stakeholders and policy makers for the need to deliver family-based services in cancer genetic counselling, with adequate planning and collaborative involvement of different professionals.

Neural Processing of Target Distance by Echolocating Bats: Functional Roles of the Auditory Midbrain

PubMed Central

Wenstrup, Jeffrey J.; Portfors, Christine V.

2011-01-01

Using their biological sonar, bats estimate distance to avoid obstacles and capture moving prey. The primary distance cue is the delay between the bat's emitted echolocation pulse and the return of an echo. The mustached bat's auditory midbrain (inferior colliculus, IC) is crucial to the analysis of pulse-echo delay. IC neurons are selective for certain delays between frequency modulated (FM) elements of the pulse and echo. One role of the IC is to create these “delay-tuned”, “FM-FM” response properties through a series of spectro-temporal integrative interactions. A second major role of the midbrain is to project target distance information to many parts of the brain. Pathways through auditory thalamus undergo radical reorganization to create highly ordered maps of pulse-echo delay in auditory cortex, likely contributing to perceptual features of target distance analysis. FM-FM neurons in IC also project strongly to pre-motor centers including the pretectum and the pontine nuclei. These pathways may contribute to rapid adjustments in flight, body position, and sonar vocalizations that occur as a bat closes in on a target. PMID:21238485

Orientation-crowding within contours.

PubMed

Glen, James C; Dakin, Steven C

2013-07-15

We examined how crowding (the breakdown of object recognition in the periphery caused by interference from "clutter") depends on the global arrangement of target and distracting flanker elements. Specifically we probed orientation discrimination using a near-vertical target Gabor flanked by two vertical distractor Gabors (one above and one below the target). By applying variable (opposite-sign) horizontal offsets to the positions of the two flankers we arranged the elements so that on some trials they formed contours with the target and on others they did not. While the presence of flankers generally elevated orientation discrimination thresholds for the target we observe maximal crowding not when flanker and targets were co-aligned but when a small spatial offset was applied to flanker location, so that contours formed between flanker and targets only when the target orientation was cued. We also report that observers' orientation judgments are biased, with target orientation appearing either attracted or repulsed by the global/contour orientation. A second experiment reveals that the sign of this effect is dependent both on observer and on eccentricity. In general, the magnitude of repulsion is reduced with eccentricity but whether this becomes attraction (of element orientation to contour orientation) is dependent on observer. We note however that across observers and eccentricities, the magnitude of repulsion correlates positively with the amount of release from crowding observed with co-aligned targets and flankers, supporting the notion of fluctuating bias as the basis for elevated crowding within contours.

"Just Be Quiet and Listen to Exactly What He's Saying": Conceptualising Power Relations in Inquiry-Oriented Classrooms

ERIC Educational Resources Information Center

Donnelly, Dermot Francis; McGarr, Oliver; O'Reilly, John

2014-01-01

Interest in inquiry-based science education (IBSE) often pays little heed to the complex power relations that exist within classrooms. A common obstacle to inquiry is that it strongly diverges from current classroom culture and hence, is outside the sphere of teachers' and students' experiences. Teachers and students bring expectations to the…

The development of an indoor mobility course for the evaluation of electronic mobility aids for persons who are visually impaired.

PubMed

Roentgen, Uta R; Gelderblom, Gert Jan; de Witte, Luc P

2012-01-01

To develop a suitable mobility course for the assessment of mobility performance as part of a user evaluation of Electronic Mobility Aids (EMA) aimed at obstacle detection and orientation. A review of the literature led to a list of critical factors for the assessment of mobility performance of persons who are visually impaired. Based upon that list, method, test situations, and determining elements were selected and presented to Dutch orientation and mobility experts. Due to expert advice and a pilot study, minor changes were made and the final version was used for the evaluation of two EMA by eight persons who are visually impaired. The results of the literature study are summarized in an overview of critical factors for the assessment of the mobility performance of persons who are visually impaired. Applied to the requirements of the above mentioned user evaluation a replicable indoor mobility course has been described in detail and tested. Based upon evidence from literature an indoor mobility course has been developed, which was sensitive to assess differences in mobility incidents and obstacle detection when using an EMA compared to the regular mobility aid. Experts' opinion confirmed its face and content validity.

Radar-based collision avoidance for unmanned surface vehicles

NASA Astrophysics Data System (ADS)

Zhuang, Jia-yuan; Zhang, Lei; Zhao, Shi-qi; Cao, Jian; Wang, Bo; Sun, Han-bing

2016-12-01

Unmanned surface vehicles (USVs) have become a focus of research because of their extensive applications. To ensure safety and reliability and to perform complex tasks autonomously, USVs are required to possess accurate perception of the environment and effective collision avoidance capabilities. To achieve these, investigation into realtime marine radar target detection and autonomous collision avoidance technologies is required, aiming at solving the problems of noise jamming, uneven brightness, target loss, and blind areas in marine radar images. These technologies should also satisfy the requirements of real-time and reliability related to high navigation speeds of USVs. Therefore, this study developed an embedded collision avoidance system based on the marine radar, investigated a highly real-time target detection method which contains adaptive smoothing algorithm and robust segmentation algorithm, developed a stable and reliable dynamic local environment model to ensure the safety of USV navigation, and constructed a collision avoidance algorithm based on velocity obstacle (V-obstacle) which adjusts the USV's heading and speed in real-time. Sea trials results in multi-obstacle avoidance firstly demonstrate the effectiveness and efficiency of the proposed avoidance system, and then verify its great adaptability and relative stability when a USV sailing in a real and complex marine environment. The obtained results will improve the intelligent level of USV and guarantee the safety of USV independent sailing.

Orientation perception in rhesus monkeys (Macaca mulatta).

PubMed

Wakita, Masumi

2008-07-01

It was previously demonstrated that monkeys divide the orientation continuum into cardinal and oblique categories. However, it is still unclear how monkeys perceive within-category orientations. To better understand monkeys' perception of orientation, two experiments were conducted using five monkeys. In experiment 1, they were trained to identify either one cardinal or one oblique target orientation out of six orientations. The results showed that they readily identified the cardinal target whether it was oriented horizontally or vertically. However, a longer training period was needed to identify the oblique target orientation regardless of its degree and direction of tilt. In experiment 2, the same monkeys were trained to identify two-oblique target orientations out of six orientations. These orientations were paired, either sharing the degree of tilt, direction of tilt, or neither property. The results showed that the monkeys readily identified oblique orientations when they had either the same degree or direction of tilt. However, when the target orientations had neither the same degree nor direction of tilt, the animals had difficulty in identifying them. In summary, horizontal and vertical orientations are individually processed, indicating that monkeys do not have a category for cardinal orientation, but they may recognize cardinal orientations as non-obliques. In addition, monkeys efficiently abstract either the degree or the direction of tilt from oblique orientations, but they have difficulty combining these features to identify an oblique orientation. Thus, not all orientations within the oblique category are equally perceived.

Distinct retinal pathways drive spatial orientation behaviors in zebrafish navigation.

PubMed

Burgess, Harold A; Schoch, Hannah; Granato, Michael

2010-02-23

Navigation requires animals to adjust ongoing movements in response to pertinent features of the environment and select between competing target cues. The neurobiological basis of navigational behavior in vertebrates is hard to analyze, partly because underlying neural circuits are experience dependent. Phototaxis in zebrafish is a hardwired navigational behavior, performed at a stage when larvae swim by using a small repertoire of stereotyped movements. We established conditions to elicit robust phototaxis behavior and found that zebrafish larvae deploy directional orienting maneuvers and regulate forward swimming speed to navigate toward a target light. Using genetic analysis and targeted laser ablations, we show that retinal ON and OFF pathways play distinct roles during phototaxis. The retinal OFF pathway controls turn movements via retinotectal projections and establishes correct orientation by causing larvae to turn away from nontarget areas. In contrast, the retinal ON pathway activates the serotonergic system to trigger rapid forward swimming toward the target. Computational simulation of phototaxis with an OFF-turn, ON-approach algorithm verifies that our model accounts for key features of phototaxis and provides a simple and robust mechanism for behavioral choice between competing targets. Copyright 2010 Elsevier Ltd. All rights reserved.

Lossless and Sufficient - Invariant Decomposition of Deterministic Target

NASA Astrophysics Data System (ADS)

Paladini, Riccardo; Ferro Famil, Laurent; Pottier, Eric; Martorella, Marco; Berizzi, Fabrizio

2011-03-01

The symmetric radar scattering matrix of a reciprocal target is projected on the circular polarization basis and is decomposed into four orientation invariant parameters, relative phase and relative orientation. The physical interpretation of this results is found in the wave-particle nature of radar scattering due to the circular polarization nature of elemental packets of energy. The proposed decomposition, is based on left orthogonal to left Special Unitary basis, providing the target description in term of a unitary vector. A comparison between the proposed CTD and Cameron, Kennaugh and Krogager decompositions is also pointed out. A validation by the use of both anechoic chamber data and airborne EMISAR data of DTU is used to show the effectiveness of this decomposition for the analysis of coherent targets. In the second paper we will show the application of the rotation group U(3) for the decomposition of distributed targets into nine meaningful parameters.

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.

Selection is more intelligent than design: improving the affinity of a bivalent ligand through directed evolution.

PubMed

Ahmad, Kareem M; Xiao, Yi; Soh, H Tom

2012-12-01

Multivalent molecular interactions can be exploited to dramatically enhance the performance of an affinity reagent. The enhancement in affinity and specificity achieved with a multivalent construct depends critically on the effectiveness of the scaffold that joins the ligands, as this determines their positions and orientations with respect to the target molecule. Currently, no generalizable design rules exist for construction of an optimal multivalent ligand for targets with known structures, and the design challenge remains an insurmountable obstacle for the large number of proteins whose structures are not known. As an alternative to such design-based strategies, we report here a directed evolution-based method for generating optimal bivalent aptamers. To demonstrate this approach, we fused two thrombin aptamers with a randomized DNA sequence and used a microfluidic in vitro selection strategy to isolate scaffolds with exceptionally high affinities. Within five rounds of selection, we generated a bivalent aptamer that binds thrombin with an apparent dissociation constant (K(d)) <10 pM, representing a ∼200-fold improvement in binding affinity over the monomeric aptamers and a ∼15-fold improvement over the best designed bivalent construct. The process described here can be used to produce high-affinity multivalent aptamers and could potentially be adapted to other classes of biomolecules.

The effects of target distance on pivot hip, trunk, pelvis, and kicking leg kinematics in Taekwondo roundhouse kicks.

PubMed

Kim, Jae-Woong; Kwon, Moon-Seok; Yenuga, Sree Sushma; Kwon, Young-Hoooo

2010-06-01

The study purpose was to investigate the effects of target distance on pivot hip, trunk, pelvis, and kicking leg movements in Taekwondo roundhouse kick. Twelve male black-belt holders executed roundhouse kicks for three target distances (Normal, Short, and Long). Linear displacements of the pivot hip and orientation angles of the pelvis, trunk, right thigh, and right shank were obtained through a three-dimensional video motion analysis. Select displacements, distances, peak orientation angles, and angle ranges were compared among the conditions using one-way repeated measure ANOVA (p < 0.05). Several orientation angle variables (posterior tilt range, peak right-tilted position, peak right-rotated position, peak left-rotated position, and left rotation range of the pelvis; peak hyperextended position and peak right-flexed position of the trunk; peak flexed position, flexion range and peak internal-rotated position of the hip) as well as the linear displacements of the pivot hip and the reach significantly changed in response to different target distances. It was concluded that the adjustment to different target distances was mainly accomplished through the pivot hip displacements, hip flexion, and pelvis left rotation. Target distance mainly affected the reach control function of the pelvis and the linear balance function of the trunk.

Automated image-based phenotypic analysis in zebrafish embryos

PubMed Central

Vogt, Andreas; Cholewinski, Andrzej; Shen, Xiaoqiang; Nelson, Scott; Lazo, John S.; Tsang, Michael; Hukriede, Neil A.

2009-01-01

Presently, the zebrafish is the only vertebrate model compatible with contemporary paradigms of drug discovery. Zebrafish embryos are amenable to automation necessary for high-throughput chemical screens, and optical transparency makes them potentially suited for image-based screening. However, the lack of tools for automated analysis of complex images presents an obstacle to utilizing the zebrafish as a high-throughput screening model. We have developed an automated system for imaging and analyzing zebrafish embryos in multi-well plates regardless of embryo orientation and without user intervention. Images of fluorescent embryos were acquired on a high-content reader and analyzed using an artificial intelligence-based image analysis method termed Cognition Network Technology (CNT). CNT reliably detected transgenic fluorescent embryos (Tg(fli1:EGFP)y1) arrayed in 96-well plates and quantified intersegmental blood vessel development in embryos treated with small molecule inhibitors of anigiogenesis. The results demonstrate it is feasible to adapt image-based high-content screening methodology to measure complex whole organism phenotypes. PMID:19235725

Stereo-vision-based terrain mapping for off-road autonomous navigation

NASA Astrophysics Data System (ADS)

Rankin, Arturo L.; Huertas, Andres; Matthies, Larry H.

2009-05-01

Successful off-road autonomous navigation by an unmanned ground vehicle (UGV) requires reliable perception and representation of natural terrain. While perception algorithms are used to detect driving hazards, terrain mapping algorithms are used to represent the detected hazards in a world model a UGV can use to plan safe paths. There are two primary ways to detect driving hazards with perception sensors mounted to a UGV: binary obstacle detection and traversability cost analysis. Binary obstacle detectors label terrain as either traversable or non-traversable, whereas, traversability cost analysis assigns a cost to driving over a discrete patch of terrain. In uncluttered environments where the non-obstacle terrain is equally traversable, binary obstacle detection is sufficient. However, in cluttered environments, some form of traversability cost analysis is necessary. The Jet Propulsion Laboratory (JPL) has explored both approaches using stereo vision systems. A set of binary detectors has been implemented that detect positive obstacles, negative obstacles, tree trunks, tree lines, excessive slope, low overhangs, and water bodies. A compact terrain map is built from each frame of stereo images. The mapping algorithm labels cells that contain obstacles as nogo regions, and encodes terrain elevation, terrain classification, terrain roughness, traversability cost, and a confidence value. The single frame maps are merged into a world map where temporal filtering is applied. In previous papers, we have described our perception algorithms that perform binary obstacle detection. In this paper, we summarize the terrain mapping capabilities that JPL has implemented during several UGV programs over the last decade and discuss some challenges to building terrain maps with stereo range data.

Stereo Vision Based Terrain Mapping for Off-Road Autonomous Navigation

NASA Technical Reports Server (NTRS)

Rankin, Arturo L.; Huertas, Andres; Matthies, Larry H.

2009-01-01

Successful off-road autonomous navigation by an unmanned ground vehicle (UGV) requires reliable perception and representation of natural terrain. While perception algorithms are used to detect driving hazards, terrain mapping algorithms are used to represent the detected hazards in a world model a UGV can use to plan safe paths. There are two primary ways to detect driving hazards with perception sensors mounted to a UGV: binary obstacle detection and traversability cost analysis. Binary obstacle detectors label terrain as either traversable or non-traversable, whereas, traversability cost analysis assigns a cost to driving over a discrete patch of terrain. In uncluttered environments where the non-obstacle terrain is equally traversable, binary obstacle detection is sufficient. However, in cluttered environments, some form of traversability cost analysis is necessary. The Jet Propulsion Laboratory (JPL) has explored both approaches using stereo vision systems. A set of binary detectors has been implemented that detect positive obstacles, negative obstacles, tree trunks, tree lines, excessive slope, low overhangs, and water bodies. A compact terrain map is built from each frame of stereo images. The mapping algorithm labels cells that contain obstacles as no-go regions, and encodes terrain elevation, terrain classification, terrain roughness, traversability cost, and a confidence value. The single frame maps are merged into a world map where temporal filtering is applied. In previous papers, we have described our perception algorithms that perform binary obstacle detection. In this paper, we summarize the terrain mapping capabilities that JPL has implemented during several UGV programs over the last decade and discuss some challenges to building terrain maps with stereo range data.

Obstacle Detection using Binocular Stereo Vision in Trajectory Planning for Quadcopter Navigation

NASA Astrophysics Data System (ADS)

Bugayong, Albert; Ramos, Manuel, Jr.

2018-02-01

Quadcopters are one of the most versatile unmanned aerial vehicles due to its vertical take-off and landing as well as hovering capabilities. This research uses the Sum of Absolute Differences (SAD) block matching algorithm for stereo vision. A complementary filter was used in sensor fusion to combine obtained quadcopter orientation data from the accelerometer and the gyroscope. PID control was implemented for the motor control and VFH+ algorithm was implemented for trajectory planning. Results show that the quadcopter was able to consistently actuate itself in the roll, yaw and z-axis during obstacle avoidance but was however found to be inconsistent in the pitch axis during forward and backward maneuvers due to the significant noise present in the pitch axis angle outputs compared to the roll and yaw axes.

Texture orientation-based algorithm for detecting infrared maritime targets.

PubMed

Wang, Bin; Dong, Lili; Zhao, Ming; Wu, Houde; Xu, Wenhai

2015-05-20

Infrared maritime target detection is a key technology for maritime target searching systems. However, in infrared maritime images (IMIs) taken under complicated sea conditions, background clutters, such as ocean waves, clouds or sea fog, usually have high intensity that can easily overwhelm the brightness of real targets, which is difficult for traditional target detection algorithms to deal with. To mitigate this problem, this paper proposes a novel target detection algorithm based on texture orientation. This algorithm first extracts suspected targets by analyzing the intersubband correlation between horizontal and vertical wavelet subbands of the original IMI on the first scale. Then the self-adaptive wavelet threshold denoising and local singularity analysis of the original IMI is combined to remove false alarms further. Experiments show that compared with traditional algorithms, this algorithm can suppress background clutter much better and realize better single-frame detection for infrared maritime targets. Besides, in order to guarantee accurate target extraction further, the pipeline-filtering algorithm is adopted to eliminate residual false alarms. The high practical value and applicability of this proposed strategy is backed strongly by experimental data acquired under different environmental conditions.

Multiple groups of orientation-selective visual mechanisms underlying rapid orientated-line detection.

PubMed Central

Foster, D H; Westland, S

1998-01-01

Visual search for an edge or line element differing in orientation from a background of other edge or line elements can be performed rapidly and effortlessly. In this study, based on psychophysical measurements with ten human observers, threshold values of the angle between a target and background line elements were obtained as functions of background-element orientation, in brief masked displays. A repeated-loess analysis of the threshold functions suggested the existence of several groups of orientation-selective mechanisms contributing to rapid orientated-line detection; specifically, coarse, intermediate and fine mechanisms with preferred orientations spaced at angles of approximately 90 degrees, 35 degrees, and 10 degrees-25 degrees, respectively. The preferred orientations of coarse and some intermediate mechanisms coincided with the vertical or horizontal of the frontoparallel plane, but the preferred orientations of fine mechanisms varied randomly from observer to observer, possibly reflecting individual variations in neuronal sampling characteristics. PMID:9753784

Optimal partial mass transportation and obstacle Monge-Kantorovich equation

NASA Astrophysics Data System (ADS)

Igbida, Noureddine; Nguyen, Van Thanh

2018-05-01

Optimal partial mass transport, which is a variant of the optimal transport problem, consists in transporting effectively a prescribed amount of mass from a source to a target. The problem was first studied by Caffarelli and McCann (2010) [6] and Figalli (2010) [12] with a particular attention to the quadratic cost. Our aim here is to study the optimal partial mass transport problem with Finsler distance costs including the Monge cost given by the Euclidian distance. Our approach is different and our results do not follow from previous works. Among our results, we introduce a PDE of Monge-Kantorovich type with a double obstacle to characterize active submeasures, Kantorovich potential and optimal flow for the optimal partial transport problem. This new PDE enables us to study the uniqueness and monotonicity results for the active submeasures. Another interesting issue of our approach is its convenience for numerical analysis and computations that we develop in a separate paper [14] (Igbida and Nguyen, 2018).

Postdictive modulation of visual orientation.

PubMed

Kawabe, Takahiro

2012-01-01

The present study investigated how visual orientation is modulated by subsequent orientation inputs. Observers were presented a near-vertical Gabor patch as a target, followed by a left- or right-tilted second Gabor patch as a distracter in the spatial vicinity of the target. The task of the observers was to judge whether the target was right- or left-tilted (Experiment 1) or whether the target was vertical or not (Supplementary experiment). The judgment was biased toward the orientation of the distracter (the postdictive modulation of visual orientation). The judgment bias peaked when the target and distracter were temporally separated by 100 ms, indicating a specific temporal mechanism for this phenomenon. However, when the visibility of the distracter was reduced via backward masking, the judgment bias disappeared. On the other hand, the low-visibility distracter could still cause a simultaneous orientation contrast, indicating that the distracter orientation is still processed in the visual system (Experiment 2). Our results suggest that the postdictive modulation of visual orientation stems from spatiotemporal integration of visual orientation on the basis of a slow feature matching process.

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

Robust analysis of an underwater navigational strategy in electrically heterogeneous corridors.

PubMed

Dimble, Kedar D; Ranganathan, Badri N; Keshavan, Jishnu; Humbert, J Sean

2016-08-01

Obstacles and other global stimuli provide relevant navigational cues to a weakly electric fish. In this work, robust analysis of a control strategy based on electrolocation for performing obstacle avoidance in electrically heterogeneous corridors is presented and validated. Static output feedback control is shown to achieve the desired goal of reflexive obstacle avoidance in such environments in simulation and experimentation. The proposed approach is computationally inexpensive and readily implementable on a small scale underwater vehicle, making underwater autonomous navigation feasible in real-time.

Trip-oriented travel time prediction (TOTTP) with historical vehicle trajectories

NASA Astrophysics Data System (ADS)

Xu, Tao; Li, Xiang; Claramunt, Christophe

2018-06-01

Accurate travel time prediction is undoubtedly of importance to both traffic managers and travelers. In highly-urbanized areas, trip-oriented travel time prediction (TOTTP) is valuable to travelers rather than traffic managers as the former usually expect to know the travel time of a trip which may cross over multiple road sections. There are two obstacles to the development of TOTTP, including traffic complexity and traffic data coverage.With large scale historical vehicle trajectory data and meteorology data, this research develops a BPNN-based approach through integrating multiple factors affecting trip travel time into a BPNN model to predict trip-oriented travel time for OD pairs in urban network. Results of experiments demonstrate that it helps discover the dominate trends of travel time changes daily and weekly, and the impact of weather conditions is non-trivial.

Masking reduces orientation selectivity in rat visual cortex

PubMed Central

Alwis, Dasuni S.; Richards, Katrina L.

2016-01-01

In visual masking the perception of a target stimulus is impaired by a preceding (forward) or succeeding (backward) mask stimulus. The illusion is of interest because it allows uncoupling of the physical stimulus, its neuronal representation, and its perception. To understand the neuronal correlates of masking, we examined how masks affected the neuronal responses to oriented target stimuli in the primary visual cortex (V1) of anesthetized rats (n = 37). Target stimuli were circular gratings with 12 orientations; mask stimuli were plaids created as a binarized sum of all possible target orientations. Spatially, masks were presented either overlapping or surrounding the target. Temporally, targets and masks were presented for 33 ms, but the stimulus onset asynchrony (SOA) of their relative appearance was varied. For the first time, we examine how spatially overlapping and center-surround masking affect orientation discriminability (rather than visibility) in V1. Regardless of the spatial or temporal arrangement of stimuli, the greatest reductions in firing rate and orientation selectivity occurred for the shortest SOAs. Interestingly, analyses conducted separately for transient and sustained target response components showed that changes in orientation selectivity do not always coincide with changes in firing rate. Given the near-instantaneous reductions observed in orientation selectivity even when target and mask do not spatially overlap, we suggest that monotonic visual masking is explained by a combination of neural integration and lateral inhibition. PMID:27535373

Obstacle negotiation control for a mobile robot suspended on overhead ground wires by optoelectronic sensors

NASA Astrophysics Data System (ADS)

Zheng, Li; Yi, Ruan

2009-11-01

Power line inspection and maintenance already benefit from developments in mobile robotics. This paper presents mobile robots capable of crossing obstacles on overhead ground wires. A teleoperated robot realizes inspection and maintenance tasks on power transmission line equipment. The inspection robot is driven by 11 motor with two arms, two wheels and two claws. The inspection robot is designed to realize the function of observation, grasp, walk, rolling, turn, rise, and decline. This paper is oriented toward 100% reliable obstacle detection and identification, and sensor fusion to increase the autonomy level. An embedded computer based on PC/104 bus is chosen as the core of control system. Visible light camera and thermal infrared Camera are both installed in a programmable pan-and-tilt camera (PPTC) unit. High-quality visual feedback rapidly becomes crucial for human-in-the-loop control and effective teleoperation. The communication system between the robot and the ground station is based on Mesh wireless networks by 700 MHz bands. An expert system programmed with Visual C++ is developed to implement the automatic control. Optoelectronic laser sensors and laser range scanner were installed in robot for obstacle-navigation control to grasp the overhead ground wires. A novel prototype with careful considerations on mobility was designed to inspect the 500KV power transmission lines. Results of experiments demonstrate that the robot can be applied to execute the navigation and inspection tasks.

Tailoring Lipid and Polymeric Nanoparticles as siRNA Carriers towards the Blood-Brain Barrier - from Targeting to Safe Administration.

PubMed

Gomes, Maria João; Fernandes, Carlos; Martins, Susana; Borges, Fernanda; Sarmento, Bruno

2017-03-01

Blood-brain barrier is a tightly packed layer of endothelial cells surrounding the brain that acts as the main obstacle for drugs enter the central nervous system (CNS), due to its unique features, as tight junctions and drug efflux systems. Therefore, since the incidence of CNS disorders is increasing worldwide, medical therapeutics need to be improved. Consequently, aiming to surpass blood-brain barrier and overcome CNS disabilities, silencing P-glycoprotein as a drug efflux transporter at brain endothelial cells through siRNA is considered a promising approach. For siRNA enzymatic protection and efficient delivery to its target, two different nanoparticles platforms, solid lipid (SLN) and poly-lactic-co-glycolic (PLGA) nanoparticles were used in this study. Polymeric PLGA nanoparticles were around 115 nm in size and had 50 % of siRNA association efficiency, while SLN presented 150 nm and association efficiency close to 52 %. Their surface was functionalized with a peptide-binding transferrin receptor, in a site-oriented manner confirmed by NMR, and their targeting ability against human brain endothelial cells was successfully demonstrated by fluorescence microscopy and flow cytometry. The interaction of modified nanoparticles with brain endothelial cells increased 3-fold compared to non-modified lipid nanoparticles, and 4-fold compared to non-modified PLGA nanoparticles, respectively. These nanosystems, which were also demonstrated to be safe for human brain endothelial cells, without significant cytotoxicity, bring a new hopeful breath to the future of brain diseases therapies.

Illustration of cross flow of polystyrene melts through a coathanger die

NASA Astrophysics Data System (ADS)

Schöppner, V.; Henke, B.

2015-05-01

To design an optimal coathanger die with a uniform flow rate distribution and low pressure drop, it is essential to understand the flow conditions in the die. This is important because the quality of the product is influenced by the flow velocity and the flow rate distribution. In extrusion dies, cross flows also occur in addition to the main flow, which flow perpendicular to the main flow. This results in pressure gradients in the extrusion direction, which have an influence on flow distribution and pressure drop in the die. In recent decades, quantitative representation and analysis of physical flow processes have made considerable progress in predicting the weather, developing drive technologies and designing aircraft using simulation methods and lab trials. Using the flow-line method, the flow is analyzed in flat film extrusion dies with a rectangular cross-section, in particular cross flows. The simplest method to visualize the flow is based on the measurement of obstacle orientation in the flow field by adding individual particles. A near-surface flow field can be visualized by using wool or textile yarns. By sticking thin, frayed at the ends of strands of wool surface that is to be examined cross flows, near-wall profiles of the flow and vortex and separation regions can be visualized. A further possibility is to add glass fibers and analyze the fiber orientation by microscopy and x-ray analysis. In this paper the influence of process parameters (e.g. melt temperatures and throughput) on cross flow and fiber orientation is described.

THz optical design considerations and optimization for medical imaging applications

NASA Astrophysics Data System (ADS)

Sung, Shijun; Garritano, James; Bajwa, Neha; Nowroozi, Bryan; Llombart, Nuria; Grundfest, Warren; Taylor, Zachary D.

2014-09-01

THz imaging system design will play an important role making possible imaging of targets with arbitrary properties and geometries. This study discusses design consideration and imaging performance optimization techniques in THz quasioptical imaging system optics. Analysis of field and polarization distortion by off-axis parabolic (OAP) mirrors in THz imaging optics shows how distortions are carried in a series of mirrors while guiding the THz beam. While distortions of the beam profile by individual mirrors are not significant, these effects are compounded by a series of mirrors in antisymmetric orientation. It is shown that symmetric orientation of the OAP mirror effectively cancels this distortion to recover the original beam profile. Additionally, symmetric orientation can correct for some geometrical off-focusing due to misalignment. We also demonstrate an alternative method to test for overall system optics alignment by investigating the imaging performance of the tilted target plane. Asymmetric signal profile as a function of the target plane's tilt angle indicates when one or more imaging components are misaligned, giving a preferred tilt direction. Such analysis can offer additional insight into often elusive source device misalignment at an integrated system. Imaging plane tilting characteristics are representative of a 3-D modulation transfer function of the imaging system. A symmetric tilted plane is preferred to optimize imaging performance.

Ultrasound-guided three-dimensional needle steering in biological tissue with curved surfaces

PubMed Central

Abayazid, Momen; Moreira, Pedro; Shahriari, Navid; Patil, Sachin; Alterovitz, Ron; Misra, Sarthak

2015-01-01

In this paper, we present a system capable of automatically steering a bevel-tipped flexible needle under ultrasound guidance toward a physical target while avoiding a physical obstacle embedded in gelatin phantoms and biological tissue with curved surfaces. An ultrasound pre-operative scan is performed for three-dimensional (3D) target localization and shape reconstruction. A controller based on implicit force control is developed to align the transducer with curved surfaces to assure the maximum contact area, and thus obtain an image of sufficient quality. We experimentally investigate the effect of needle insertion system parameters such as insertion speed, needle diameter and bevel angle on target motion to adjust the parameters that minimize the target motion during insertion. A fast sampling-based path planner is used to compute and periodically update a feasible path to the target that avoids obstacles. We present experimental results for target reconstruction and needle insertion procedures in gelatin-based phantoms and biological tissue. Mean targeting errors of 1.46 ± 0.37 mm, 1.29 ± 0.29 mm and 1.82 ± 0.58 mm are obtained for phantoms with inclined, curved and combined (inclined and curved) surfaces, respectively, for insertion distance of 86–103 mm. The achieved targeting errors suggest that our approach is sufficient for targeting lesions of 3 mm radius that can be detected using clinical ultrasound imaging systems. PMID:25455165

Assistive obstacle detection and navigation devices for vision-impaired users.

PubMed

Ong, S K; Zhang, J; Nee, A Y C

2013-09-01

Quality of life for the visually impaired is an urgent worldwide issue that needs to be addressed. Obstacle detection is one of the most important navigation tasks for the visually impaired. In this research, a novel range sensor placement scheme is proposed in this paper for the development of obstacle detection devices. Based on this scheme, two prototypes have been developed targeting at different user groups. This paper discusses the design issues, functional modules and the evaluation tests carried out for both prototypes. Implications for Rehabilitation Visual impairment problem is becoming more severe due to the worldwide ageing population. Individuals with visual impairment require assistance from assistive devices in daily navigation tasks. Traditional assistive devices that assist navigation may have certain drawbacks, such as the limited sensing range of a white cane. Obstacle detection devices applying the range sensor technology can identify road conditions with a higher sensing range to notify the users of potential dangers in advance.

Integrating Millimeter Wave Radar with a Monocular Vision Sensor for On-Road Obstacle Detection Applications

PubMed Central

Wang, Tao; Zheng, Nanning; Xin, Jingmin; Ma, Zheng

2011-01-01

This paper presents a systematic scheme for fusing millimeter wave (MMW) radar and a monocular vision sensor for on-road obstacle detection. As a whole, a three-level fusion strategy based on visual attention mechanism and driver’s visual consciousness is provided for MMW radar and monocular vision fusion so as to obtain better comprehensive performance. Then an experimental method for radar-vision point alignment for easy operation with no reflection intensity of radar and special tool requirements is put forward. Furthermore, a region searching approach for potential target detection is derived in order to decrease the image processing time. An adaptive thresholding algorithm based on a new understanding of shadows in the image is adopted for obstacle detection, and edge detection is used to assist in determining the boundary of obstacles. The proposed fusion approach is verified through real experimental examples of on-road vehicle/pedestrian detection. In the end, the experimental results show that the proposed method is simple and feasible. PMID:22164117

Integrating millimeter wave radar with a monocular vision sensor for on-road obstacle detection applications.

PubMed

Wang, Tao; Zheng, Nanning; Xin, Jingmin; Ma, Zheng

2011-01-01

This paper presents a systematic scheme for fusing millimeter wave (MMW) radar and a monocular vision sensor for on-road obstacle detection. As a whole, a three-level fusion strategy based on visual attention mechanism and driver's visual consciousness is provided for MMW radar and monocular vision fusion so as to obtain better comprehensive performance. Then an experimental method for radar-vision point alignment for easy operation with no reflection intensity of radar and special tool requirements is put forward. Furthermore, a region searching approach for potential target detection is derived in order to decrease the image processing time. An adaptive thresholding algorithm based on a new understanding of shadows in the image is adopted for obstacle detection, and edge detection is used to assist in determining the boundary of obstacles. The proposed fusion approach is verified through real experimental examples of on-road vehicle/pedestrian detection. In the end, the experimental results show that the proposed method is simple and feasible.

HPC-Microgels: New Look at Structure and Dynamics

NASA Astrophysics Data System (ADS)

McKenna, John; Streletzky, Kiril; Mohieddine, Rami

2006-10-01

Issues remain unresolved in targeted chemotherapy including: an inability to effectively target cancerous tissue, the loss of low molecular weight medicines to the RES system, the high cytotoxicity of currently used drug carriers, and the inability to control the release of medicines upon arrival to the target. Hydroxy-propyl cellulose(HPC) microgels may be able to surmount these obstacles. HPC is a high molecular weight polymer with low cytotoxicity and a critical temperature around 41C. We cross-linked HPC polymer chains to produce microgel nanoparticles and studied their structure and dynamics using Dynamic Light Scattering spectroscopy. The complex nature of the fluid and large size distribution of the particles renders typical characterization algorithm CONTIN ineffective and inconsistent. Instead, the particles spectra have been fit to a sum of stretched exponentials. Each term offers three parameters for analysis and represents a single mode. The results of this analysis show that the microgels undergo a multi to uni-modal transition around 41C. The CONTIN size distribution analysis shows similar results, but these come with much less consistency and resolution. During the phase transition it is found that the microgel particles actually shrink. This property might be particularly useful for controlled drug delivery and release.

Role of curvatures in determining the characteristics of a string vibrating against a doubly curved obstacle

NASA Astrophysics Data System (ADS)

Singh, Harkirat; Wahi, Pankaj

2017-08-01

The motion of a string in the presence of a doubly curved obstacle is investigated. A mathematical model has been developed for a general shape of the obstacle. However, detailed analysis has been performed for a shape relevant to the Indian stringed musical instruments like Tanpura and Sitar. In particular, we explore the effect of obstacle's curvature in the plane perpendicular to the string axis on its motion. This geometrical feature of the obstacle introduces a coupling between motions in mutually perpendicular directions over and above the coupling due to the stretching nonlinearity. We find that only one planar motion is possible for our system. Small amplitude planar motions are stable to perturbations in the perpendicular direction resulting in non-whirling motions while large amplitude oscillations lead to whirling motions. The critical amplitude of oscillations, across which there is a transition in the qualitative behavior of the non-planar trajectories, is determined using Floquet theory. Our analysis reveals that a small obstacle curvature in a direction perpendicular to the string axis leads to a considerable reduction in the critical amplitudes required for initiation of whirling motions. Hence, this obstacle curvature has a destabilizing effect on the planar motions in contrast to the curvature along the string axis which stabilizes planar motions.

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.

Targeting the undruggable: Advances and obstacles in current RNAi therapy

PubMed Central

Wu, Sherry Y.; Lopez-Berestein, Gabriel; Calin, George A.; Sood, Anil K.

2014-01-01

RNA interference (RNAi) therapeutics represents a rapidly emerging platform for personalized cancer treatment. Recent advances in delivery, target selection, and safety of RNAi cancer therapy provide unprecedented opportunities for clinical translation. Here, we discuss these advances and present strategies for making RNAi-based therapy a viable part of cancer management. PMID:24920658

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.

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.

[Therapeutic education in pediatric dentistry: analysis of obstacles and levers to the development of programmes in France in 2016].

PubMed

Marquillier, Thomas; Trentesaux, Thomas; Gagnayre, Rémi

2017-01-01

Over recent years, therapeutic patient education has become part of dental medicine. Management of early childhood caries, known to be a very common chronic disease, has evolved to include an educational dimension. The objective of this study was to identify the levers and barriers to the development of formalized therapeutic education programmes and alternatives. A comprehensive exploratory qualitative study was conducted between November 2015 and June 2016 on a targeted sample of 15 people aware of the problem of TPE in dentistry. The study showed that TPE training in dentistry is underdeveloped, despite its numerous benefits: change of the healthcare professional's approach, implementation of structured educational programmes, development of research, etc. There are many obstacles to the development of TPE programmes: insufficient resources, rigid legislation or lack of knowledge of TPE practices. The dental profession is an obstacle itself because of its lack of understanding and variable degrees of integration the medical community. There are multiple levers, but the main ones are changing attitudes of the profession and the provision of resources to develop TPE. Although alternatives to TPE programmes exist (accompanying measures, short educational strategies, connected health), they cannot replace TPE. More educational strategies must be developed in the field of dentistry. However, the framework of TPE must be adapted to the profession to ensure good uptake.

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

Ishii, H.; Fujino, H.; Bian, Z.

In this study, two types of marker-based tracking methods for Augmented Reality have been developed. One is a method which employs line-shaped markers and the other is a method which employs circular-shaped markers. These two methods recognize the markers by means of image processing and calculate the relative position and orientation between the markers and the camera in real time. The line-shaped markers are suitable to be pasted in the buildings such as NPPs where many pipes and tanks exist. The circular-shaped markers are suitable for the case that there are many obstacles and it is difficult to use line-shapedmore » markers because the obstacles hide the part of the line-shaped markers. Both methods can extend the maximum distance between the markers and the camera compared to the legacy marker-based tracking methods. (authors)« less

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.

Short-term perceptual learning in visual conjunction search.

PubMed

Su, Yuling; Lai, Yunpeng; Huang, Wanyi; Tan, Wei; Qu, Zhe; Ding, Yulong

2014-08-01

Although some studies showed that training can improve the ability of cross-dimension conjunction search, less is known about the underlying mechanism. Specifically, it remains unclear whether training of visual conjunction search can successfully bind different features of separated dimensions into a new function unit at early stages of visual processing. In the present study, we utilized stimulus specificity and generalization to provide a new approach to investigate the mechanisms underlying perceptual learning (PL) in visual conjunction search. Five experiments consistently showed that after 40 to 50 min of training of color-shape/orientation conjunction search, the ability to search for a certain conjunction target improved significantly and the learning effects did not transfer to a new target that differed from the trained target in both color and shape/orientation features. However, the learning effects were not strictly specific. In color-shape conjunction search, although the learning effect could not transfer to a same-shape different-color target, it almost completely transferred to a same-color different-shape target. In color-orientation conjunction search, the learning effect partly transferred to a new target that shared same color or same orientation with the trained target. Moreover, the sum of transfer effects for the same color target and the same orientation target in color-orientation conjunction search was algebraically equivalent to the learning effect for trained target, showing an additive transfer effect. The different transfer patterns in color-shape and color-orientation conjunction search learning might reflect the different complexity and discriminability between feature dimensions. These results suggested a feature-based attention enhancement mechanism rather than a unitization mechanism underlying the short-term PL of color-shape/orientation conjunction search.

State estimation for autonomous flight in cluttered environments

NASA Astrophysics Data System (ADS)

Langelaan, Jacob Willem

Safe, autonomous operation in complex, cluttered environments is a critical challenge facing autonomous mobile systems. The research described in this dissertation was motivated by a particularly difficult example of autonomous mobility: flight of a small Unmanned Aerial Vehicle (UAV) through a forest. In cluttered environments (such as forests or natural and urban canyons) signals from navigation beacons such as GPS may frequently be occluded. Direct measurements of vehicle position are therefore unavailable, and information required for flight control, obstacle avoidance, and navigation must be obtained using only on-board sensors. However, payload limitations of small UAVs restrict both the mass and physical dimensions of sensors that can be carried. This dissertation describes the development and proof-of-concept demonstration of a navigation system that uses only a low-cost inertial measurement unit and a monocular camera. Micro electromechanical inertial measurements units are well suited to small UAV applications and provide measurements of acceleration and angular rate. However, they do not provide information about nearby obstacles (needed for collision avoidance) and their noise and bias characteristics lead to unbounded growth in computed position. A monocular camera can provide bearings to nearby obstacles and landmarks. These bearings can be used both to enable obstacle avoidance and to aid navigation. Presented here is a solution to the problem of estimating vehicle state (position, orientation and velocity) as well as positions of obstacles in the environment using only inertial measurements and bearings to obstacles. This is a highly nonlinear estimation problem, and standard estimation techniques such as the Extended Kalman Filter are prone to divergence in this application. In this dissertation a Sigma Point Kalman Filter is implemented, resulting in an estimator which is able to cope with the significant nonlinearities in the system equations and uncertainty in state estimates while remaining tractable for real-time operation. In addition, the issues of data association and landmark initialization are addressed. Estimator performance is examined through Monte Carlo simulations in both two and three dimensions for scenarios involving UAV flight in cluttered environments. Hardware tests and simulations demonstrate navigation through an obstacle-strewn environment by a small Unmanned Ground Vehicle.

Cluster: A New Application for Spatial Analysis of Pixelated Data for Epiphytotics.

PubMed

Nelson, Scot C; Corcoja, Iulian; Pethybridge, Sarah J

2017-12-01

Spatial analysis of epiphytotics is essential to develop and test hypotheses about pathogen ecology, disease dynamics, and to optimize plant disease management strategies. Data collection for spatial analysis requires substantial investment in time to depict patterns in various frames and hierarchies. We developed a new approach for spatial analysis of pixelated data in digital imagery and incorporated the method in a stand-alone desktop application called Cluster. The user isolates target entities (clusters) by designating up to 24 pixel colors as nontargets and moves a threshold slider to visualize the targets. The app calculates the percent area occupied by targeted pixels, identifies the centroids of targeted clusters, and computes the relative compass angle of orientation for each cluster. Users can deselect anomalous clusters manually and/or automatically by specifying a size threshold value to exclude smaller targets from the analysis. Up to 1,000 stochastic simulations randomly place the centroids of each cluster in ranked order of size (largest to smallest) within each matrix while preserving their calculated angles of orientation for the long axes. A two-tailed probability t test compares the mean inter-cluster distances for the observed versus the values derived from randomly simulated maps. This is the basis for statistical testing of the null hypothesis that the clusters are randomly distributed within the frame of interest. These frames can assume any shape, from natural (e.g., leaf) to arbitrary (e.g., a rectangular or polygonal field). Cluster summarizes normalized attributes of clusters, including pixel number, axis length, axis width, compass orientation, and the length/width ratio, available to the user as a downloadable spreadsheet. Each simulated map may be saved as an image and inspected. Provided examples demonstrate the utility of Cluster to analyze patterns at various spatial scales in plant pathology and ecology and highlight the limitations, trade-offs, and considerations for the sensitivities of variables and the biological interpretations of results. The Cluster app is available as a free download for Apple computers at iTunes, with a link to a user guide website.

Strategic relatedness in mergers and financial performance: the case of the health maintenance organization industry in the United States.

PubMed

Weech-Maldonado, Robert

2002-11-01

Knowledge and identification of strategic factors associated with favourable post-acquisition performance can be of benefit to both managers and shareholders. From a management perspective, the identification of contextual factors that can influence postmerger performance is 'strategic' in nature, and should be considered in the analysis of future acquisitions. Within the context of the health maintenance organization (HMO) industry, this study examines the impact of strategic relatedness on postmerger financial performance. Strategic relatedness is conceptualized as similarity between the acquirer and target HMOs in terms of operational efficiency, marketing orientation, organizational structure and profit orientation. Regression analysis showed that similarity in operational efficiency and similarity in HMO structure were associated with better postmerger financial performance. However, marketing orientation similarity and profit orientation similarity were not significantly related to postmerger performance. This finding suggests that HMO mergers involving firms with similar strategic orientations and similar approaches to the delivery of care have greater strategic fit and experience better financial performance.

Factors influencing transitional care from adolescents to young adults with cancer in Taiwan: A population-based study.

PubMed

Jin, Yo-Ting; Chen, Chin-Mi; Chien, Wu-Chien

2016-08-02

To investigate the progress of transition from paediatric to adult health care for patients with cancer in Taiwan's medical system. The data were retrieved from the Longitudinal Health Insurance Database (LHID), which contains the original inpatient and outpatient medical claims data for 1,000,000 enrollees randomly sampled from the NHIRD between 1997 and 2010. Among the 1,411 cancer patients selected for this study, 98.09 % received adult-oriented therapy before the age of 18. In addition, only 1.91 % of the patients received paediatric-oriented therapy during adolescence. The primary factors that determine whether these patients would receive paediatric-oriented therapy or adult-oriented therapy at an early age were as follows: the age of the patient at the first visit and the performance-level of the hospital (p < 0.001). Previous studies conducted in developed countries have demonstrated that the unwillingness of patients to switch from paediatric-oriented therapy to adult-oriented therapy being the major obstacle that hinders the transition process. However, this study revealed a different result: the implementation of the National Health Insurance system in Taiwan makes healthcare affordable for the adolescent patients who may not possess adequate knowledge about paediatric health care and may not appreciate paediatric-oriented therapy, thereby hindering the transition process.

Selective enhancement of orientation tuning before saccades.

PubMed

Ohl, Sven; Kuper, Clara; Rolfs, Martin

2017-11-01

Saccadic eye movements cause a rapid sweep of the visual image across the retina and bring the saccade's target into high-acuity foveal vision. Even before saccade onset, visual processing is selectively prioritized at the saccade target. To determine how this presaccadic attention shift exerts its influence on visual selection, we compare the dynamics of perceptual tuning curves before movement onset at the saccade target and in the opposite hemifield. Participants monitored a 30-Hz sequence of randomly oriented gratings for a target orientation. Combining a reverse correlation technique previously used to study orientation tuning in neurons and general additive mixed modeling, we found that perceptual reports were tuned to the target orientation. The gain of orientation tuning increased markedly within the last 100 ms before saccade onset. In addition, we observed finer orientation tuning right before saccade onset. This increase in gain and tuning occurred at the saccade target location and was not observed at the incongruent location in the opposite hemifield. The present findings suggest, therefore, that presaccadic attention exerts its influence on vision in a spatially and feature-selective manner, enhancing performance and sharpening feature tuning at the future gaze location before the eyes start moving.

The analysis of selected orientation methods of architectural objects' scans

NASA Astrophysics Data System (ADS)

Markiewicz, Jakub S.; Kajdewicz, Irmina; Zawieska, Dorota

2015-05-01

The terrestrial laser scanning is commonly used in different areas, inter alia in modelling architectural objects. One of the most important part of TLS data processing is scans registration. It significantly affects the accuracy of generation of high resolution photogrammetric documentation. This process is time consuming, especially in case of a large number of scans. It is mostly based on an automatic detection and a semi-automatic measurement of control points placed on the object. In case of the complicated historical buildings, sometimes it is forbidden to place survey targets on an object or it may be difficult to distribute survey targets in the optimal way. Such problems encourage the search for the new methods of scan registration which enable to eliminate the step of placing survey targets on the object. In this paper the results of target-based registration method are presented The survey targets placed on the walls of historical chambers of the Museum of King Jan III's Palace at Wilanów and on the walls of ruins of the Bishops Castle in Iłża were used for scan orientation. Several variants of orientation were performed, taking into account different placement and different number of survey marks. Afterwards, during next research works, raster images were generated from scans and the SIFT and SURF algorithms for image processing were used to automatically search for corresponding natural points. The case of utilisation of automatically identified points for TLS data orientation was analysed. The results of both methods for TLS data registration were summarized and presented in numerical and graphical forms.

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…

Target-object integration, attention distribution, and object orientation interactively modulate object-based selection.

PubMed

Al-Janabi, Shahd; Greenberg, Adam S

2016-10-01

The representational basis of attentional selection can be object-based. Various studies have suggested, however, that object-based selection is less robust than spatial selection across experimental paradigms. We sought to examine the manner by which the following factors might explain this variation: Target-Object Integration (targets 'on' vs. part 'of' an object), Attention Distribution (narrow vs. wide), and Object Orientation (horizontal vs. vertical). In Experiment 1, participants discriminated between two targets presented 'on' an object in one session, or presented as a change 'of' an object in another session. There was no spatial cue-thus, attention was initially focused widely-and the objects were horizontal or vertical. We found evidence of object-based selection only when targets constituted a change 'of' an object. Additionally, object orientation modulated the sign of object-based selection: We observed a same-object advantage for horizontal objects, but a same-object cost for vertical objects. In Experiment 2, an informative cue preceded a single target presented 'on' an object or as a change 'of' an object (thus, attention was initially focused narrowly). Unlike in Experiment 1, we found evidence of object-based selection independent of target-object integration. We again found that the sign of selection was modulated by the objects' orientation. This result may reflect a meridian effect, which emerged due to anisotropies in the cortical representations when attention is oriented endogenously. Experiment 3 revealed that object orientation did not modulate object-based selection when attention was oriented exogenously. Our findings suggest that target-object integration, attention distribution, and object orientation modulate object-based selection, but only in combination.

Influence of turbulence, orientation, and site configuration on the response of buildings to extreme wind.

PubMed

Aly, Aly Mousaad

2014-01-01

Atmospheric turbulence results from the vertical movement of air, together with flow disturbances around surface obstacles which make low- and moderate-level winds extremely irregular. Recent advancements in wind engineering have led to the construction of new facilities for testing residential homes at relatively high Reynolds numbers. However, the generation of a fully developed turbulence in these facilities is challenging. The author proposed techniques for the testing of residential buildings and architectural features in flows that lack fully developed turbulence. While these methods are effective for small structures, the extension of the approach for large and flexible structures is not possible yet. The purpose of this study is to investigate the role of turbulence in the response of tall buildings to extreme winds. In addition, the paper presents a detailed analysis to investigate the influence of upstream terrain conditions, wind direction angle (orientation), and the interference effect from the surrounding on the response of high-rise buildings. The methodology presented can be followed to help decision makers to choose among innovative solutions like aerodynamic mitigation, structural member size adjustment, and/or damping enhancement, with an objective to improve the resiliency and the serviceability of buildings.

Influence of Turbulence, Orientation, and Site Configuration on the Response of Buildings to Extreme Wind

PubMed Central

2014-01-01

Atmospheric turbulence results from the vertical movement of air, together with flow disturbances around surface obstacles which make low- and moderate-level winds extremely irregular. Recent advancements in wind engineering have led to the construction of new facilities for testing residential homes at relatively high Reynolds numbers. However, the generation of a fully developed turbulence in these facilities is challenging. The author proposed techniques for the testing of residential buildings and architectural features in flows that lack fully developed turbulence. While these methods are effective for small structures, the extension of the approach for large and flexible structures is not possible yet. The purpose of this study is to investigate the role of turbulence in the response of tall buildings to extreme winds. In addition, the paper presents a detailed analysis to investigate the influence of upstream terrain conditions, wind direction angle (orientation), and the interference effect from the surrounding on the response of high-rise buildings. The methodology presented can be followed to help decision makers to choose among innovative solutions like aerodynamic mitigation, structural member size adjustment, and/or damping enhancement, with an objective to improve the resiliency and the serviceability of buildings. PMID:24701140

Promotion of Students' Mastery Goal Orientations: Does TARGET Work?

ERIC Educational Resources Information Center

Lüftenegger, Marko; van de Schoot, Rens; Schober, Barbara; Finsterwald, Monika; Spiel, Christiane

2014-01-01

Achievement goal orientations are important for students' ongoing motivation. Students with a mastery goal orientation show the most advantageous achievement and motivational patterns. Much research has been conducted to identify classroom structures which promote students' mastery goal orientation. The TARGET framework is one example of these…

Nonlinear regimes on polygonal hydraulic jumps

NASA Astrophysics Data System (ADS)

Rojas, Nicolas

2016-11-01

This work extends previous leading and higher order results on the polygonal hydraulic jump in the framework of inertial lubrication theory. The rotation of steady polygonal jumps is observed in the transition from one wavenumber to the next one, induced by a change in height of an external obstacle near the outer edge. In a previous publication, the study of stationary polygons is considered under the assumption that the reference frame rotates with the polygons when the number of corners change, in order to preserve their orientation. In this research work I provide a Hamiltonian approach and the stability analysis of the nonlinear oscillator that describe the polygonal structures at the jump interface, in addition to a perturbation method that enables to explain, for instance, the diversity of patterns found in experiments. GRASP, Institute of Physics, University of Liege, Belgium.

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.

Monitoring the Effective and Efficient Use of Land: The English Approach

NASA Astrophysics Data System (ADS)

Ganser, Robin

In England quantified targets for the reuse of brownfields and of existing buildings place particular requirements on the planning system as part of the overall strategy to make effective use of natural resources. Achieving these targets is not free of obstacles and potential conflicts. Therefore monitoring of policy implementation is a necessity in the planning system.

Framing the policy debate over spirits excise tax in Poland.

PubMed

Zatonski, Mateusz; Hawkins, Benjamin; McKee, Martin

2018-06-01

Industry lobbying remains an obstacle to effective health-oriented alcohol policy. In 2013, an increase in excise tax on spirits was announced by the Polish government. This article presents a qualitative analysis of the public debate that ensued on the potential economic, health and social effects of the policy. It focuses on how competing groups, including industry actors, framed their position and sought to dominate the debate. Online archives of five Polish national newspapers, two spirits trade associations, and parliamentary and ministerial archives were searched. A thematic content analysis of the identified sources was conducted. The overall findings were compared with existing research on the framing of the Minimum Unit Pricing (MUP) debate in the UK. A total of 155 sources were analysed. Two main frames were identified: health, and economic. The spirits industry successfully promoted the economic frame in their own publications and in the media. The debate was dominated by arguments about potential growth of the grey market and losses in tax revenue that might result from the excise tax increase. The framing of the debate in Poland differed from the framing of the MUP debate in the United Kingdom. The Polish public health community was unsuccessful in making health considerations a significant element of the alcohol policy debate. The strategies pursued by UK health advocates offer lessons for how to make a more substantial impact on media coverage and promote health-oriented legislation.

A 3D insight on the catalytic nanostructuration of few-layer graphene

NASA Astrophysics Data System (ADS)

Melinte, G.; Florea, I.; Moldovan, S.; Janowska, I.; Baaziz, W.; Arenal, R.; Wisnet, A.; Scheu, C.; Begin-Colin, S.; Begin, D.; Pham-Huu, C.; Ersen, O.

2014-06-01

The catalytic cutting of few-layer graphene is nowadays a hot topic in materials research due to its potential applications in the catalysis field and the graphene nanoribbons fabrication. We show here a 3D analysis of the nanostructuration of few-layer graphene by iron-based nanoparticles under hydrogen flow. The nanoparticles located at the edges or attached to the steps on the FLG sheets create trenches and tunnels with orientations, lengths and morphologies defined by the crystallography and the topography of the carbon substrate. The cross-sectional analysis of the 3D volumes highlights the role of the active nanoparticle identity on the trench size and shape, with emphasis on the topographical stability of the basal planes within the resulting trenches and channels, no matter the obstacle encountered. The actual study gives a deep insight on the impact of nanoparticles morphology and support topography on the 3D character of nanostructures built up by catalytic cutting.

Contrast, size, and orientation-invariant target detection in infrared imagery

NASA Astrophysics Data System (ADS)

Zhou, Yi-Tong; Crawshaw, Richard D.

1991-08-01

Automatic target detection in IR imagery is a very difficult task due to variations in target brightness, shape, size, and orientation. In this paper, the authors present a contrast, size, and orientation invariant algorithm based on Gabor functions for detecting targets from a single IR image frame. The algorithms consists of three steps. First, it locates potential targets by using low-resolution Gabor functions which resist noise and background clutter effects, then, it removes false targets and eliminates redundant target points based on a similarity measure. These two steps mimic human vision processing but are different from Zeevi's Foveating Vision System. Finally, it uses both low- and high-resolution Gabor functions to verify target existence. This algorithm has been successfully tested on several IR images that contain multiple examples of military vehicles with different size and brightness in various background scenes and orientations.

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.

Orbital navigation, docking and obstacle avoidance as a form of three dimensional model-based image understanding

NASA Technical Reports Server (NTRS)

Beyer, J.; Jacobus, C.; Mitchell, B.

1987-01-01

Range imagery from a laser scanner can be used to provide sufficient information for docking and obstacle avoidance procedures to be performed automatically. Three dimensional model-based computer vision algorithms in development can perform these tasks even with targets which may not be cooperative (that is, objects without special targets or markers to provide unambiguous location points). Roll, pitch and yaw of the vehicle can be taken into account as image scanning takes place, so that these can be corrected when the image is converted from egocentric to world coordinates. Other attributes of the sensor, such as the registered reflectence and texture channels, provide additional data sources for algorithm robustness. Temporal fusion of sensor immages can take place in the work coordinate domain, allowing for the building of complex maps in three dimensional space.

Sided functions of an arginine-agmatine antiporter oriented in liposomes.

PubMed

Tsai, Ming-Feng; Fang, Yiling; Miller, Christopher

2012-02-28

The arginine-dependent extreme acid resistance system helps enteric bacteria survive the harsh gastric environment. At the center of this multiprotein system is an arginine-agmatine antiporter, AdiC. To maintain cytoplasmic pH, AdiC imports arginine and exports its decarboxylated product, agmatine, resulting in a net extrusion of one "virtual proton" in each turnover. The random orientation of AdiC in reconstituted liposomes throws up an obstacle to quantifying its transport mechanism. To overcome this problem, we introduced a mutation, S26C, near the substrate-binding site. This mutant exhibits substrate recognition and pH-dependent activity similar to those of the wild-type protein but loses function completely upon reaction with thiol reagents. The membrane-impermeant MTSES reagent can then be used as a cleanly sided inhibitor to silence those S26C-AdiC proteins whose extracellular portion projects from the external side of the liposome. Alternatively, the membrane-permeant MTSEA and membrane-impermeant reducing reagent, TCEP, can be used together to inhibit proteins in the opposite orientation. This approach allows steady-state kinetic analysis of AdiC in a sided fashion. Arginine and agmatine have similar Michaelis-Menten parameters for both sides of the protein, while the extracellular side selects arginine over argininamide, a mimic of the carboxylate-protonated form of arginine, more effectively than does the cytoplasmic side. Moreover, the two sides of AdiC have different pH sensitivities. AdiC activity increases to a plateau at pH 4 as the extracellular side is acidified, while the cytoplasmic side shows an optimal pH of 5.5, with further acidification inhibiting transport. This oriented system allows more precise analysis of AdiC-mediated substrate transport than has been previously available and permits comparison to the situation experienced by the bacterial membrane under acid stress.

Obstacles to comprehensive dental care in patients with sustained limitations of their decision-making abilities: findings from a Delphi study.

PubMed

Blaizot, Alessandra; Catteau, Céline; Delfosse, Caroline; Hamel, Olivier; Trentesaux, Thomas

2018-06-01

The objective of this study was to explore the therapeutic limitations experienced by a panel of special-care dentists in France when treating patients with sustained limitations of their decision-making abilities. We used a Delphi technique conducted in three rounds from 01 June 2014 to 30 September 2015. A first questionnaire comprising open-ended questions was addressed to 72 panellists. A content analysis of the returned questionnaires served to draft a second questionnaire comprising closed-ended questions; this was sent to the 28 panellists who responded in the first round. A third questionnaire was sent to the 20 panellists who responded in the second round to give them an opportunity to reconsider their response in the context of the second-round response group. Sixteen panellists answered the last round. A large majority agreed on the importance of providing comprehensive care, but they encountered obstacles at two time points: (i) when proposing the care; and (ii) when setting it up. The panel put forward recommendations in two main areas: (i) the training of those involved in oral health decisions; and (ii) dental care management and organization of the care system. The study provided a foundation for building future orientations in health care for patients with limited decision-making abilities. © 2018 Eur J Oral Sci.

The Sensitivity Analysis for the Flow Past Obstacles Problem with Respect to the Reynolds Number

PubMed Central

Ito, Kazufumi; Li, Zhilin; Qiao, Zhonghua

2013-01-01

In this paper, numerical sensitivity analysis with respect to the Reynolds number for the flow past obstacle problem is presented. To carry out such analysis, at each time step, we need to solve the incompressible Navier-Stokes equations on irregular domains twice, one for the primary variables; the other is for the sensitivity variables with homogeneous boundary conditions. The Navier-Stokes solver is the augmented immersed interface method for Navier-Stokes equations on irregular domains. One of the most important contribution of this paper is that our analysis can predict the critical Reynolds number at which the vortex shading begins to develop in the wake of the obstacle. Some interesting experiments are shown to illustrate how the critical Reynolds number varies with different geometric settings. PMID:24910780

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.

The Sensitivity Analysis for the Flow Past Obstacles Problem with Respect to the Reynolds Number.

PubMed

Ito, Kazufumi; Li, Zhilin; Qiao, Zhonghua

2012-02-01

In this paper, numerical sensitivity analysis with respect to the Reynolds number for the flow past obstacle problem is presented. To carry out such analysis, at each time step, we need to solve the incompressible Navier-Stokes equations on irregular domains twice, one for the primary variables; the other is for the sensitivity variables with homogeneous boundary conditions. The Navier-Stokes solver is the augmented immersed interface method for Navier-Stokes equations on irregular domains. One of the most important contribution of this paper is that our analysis can predict the critical Reynolds number at which the vortex shading begins to develop in the wake of the obstacle. Some interesting experiments are shown to illustrate how the critical Reynolds number varies with different geometric settings.

A parallel implementation of a multisensor feature-based range-estimation method

NASA Technical Reports Server (NTRS)

Suorsa, Raymond E.; Sridhar, Banavar

1993-01-01

There are many proposed vision based methods to perform obstacle detection and avoidance for autonomous or semi-autonomous vehicles. All methods, however, will require very high processing rates to achieve real time performance. A system capable of supporting autonomous helicopter navigation will need to extract obstacle information from imagery at rates varying from ten frames per second to thirty or more frames per second depending on the vehicle speed. Such a system will need to sustain billions of operations per second. To reach such high processing rates using current technology, a parallel implementation of the obstacle detection/ranging method is required. This paper describes an efficient and flexible parallel implementation of a multisensor feature-based range-estimation algorithm, targeted for helicopter flight, realized on both a distributed-memory and shared-memory parallel computer.

The marketing of partial hospitalization.

PubMed

Millsap, P; Brown, E; Kiser, L; Pruitt, D

1987-09-01

Health-care professionals are currently operating in the context of a rapidly changing health-care delivery system, including the move away from inpatient services to outpatient services in order to control costs. Those who practice in partial-hospital settings are in a position to offer effective, cost-efficient services; however, there continue to be obstacles which hinder appropriate utilization of the modality. The development and use of a well-designed marketing plan is one strategy for removing these obstacles. This paper presents a brief overview of the marketing process, ideas for developing a marketing plan, and several examples of specific marketing strategies as well as ways to monitor their effectiveness. Partial-hospital providers must take an active role in answering the calls for alternative sources of psychiatric care. A comprehensive, education-oriented marketing approach will increase the public's awareness of such alternatives and enable programs to survive in a competitive environment.

Interventions to increase initial appointment attendance in mental health services: a systematic review.

PubMed

Schauman, Oliver; Aschan, Lisa Ellinor; Arias, Nicole; Beards, Stephanie; Clement, Sarah

2013-12-01

OBJECTIVE Although nonattendance at initial appointments in mental health services is a substantial problem, the phenomenon is poorly understood. This review synthesized findings of randomized controlled trials (RCTs) of interventions to increase initial appointment attendance and determined whether theories or models contributed to intervention design. METHODS Six electronic databases were systematically searched, and reference lists of identified studies were also examined. Studies included were RCTs (including "quasi-randomized" controlled trials) that compared standard practice with an intervention to increase attendance at initial appointments in a sample of adults who had a scheduled initial appointment in a mental health or substance abuse service setting. RESULTS Of 144 potentially relevant studies, 21 met inclusion criteria. These studies were reported in 20 different research papers. Of these, 16 studies (N=3,673 participants) were included in the analyses (five were excluded because they reported only nonattendance at the initial appointment). Separate analyses were conducted for each intervention type (opt-in systems, telephone reminders and prompts, orientation and reminder letters, accelerated intake, preappointment completion of psychodynamic questionnaires, and "other"). Narrative synthesis was used for analysis because the high level of heterogeneity between studies precluded a meta-analysis. The results were mixed for all types of intervention. Some isolated high-quality studies of opt-in systems, orientation and reminder letters, and more novel interventions demonstrated a beneficial effect. CONCLUSIONS The synthesized findings indicated that orientation and reminder letters may have a small beneficial effect. Consistent evidence for the efficacy of other types of common interventions is lacking. More novel interventions, such as asking clients to formulate plans to deal with obstacles to attendance and giving clients a choice of therapist style, showed some promise, but studies require replication.

CCTV Coverage Index Based on Surveillance Resolution and Its Evaluation Using 3D Spatial Analysis

PubMed Central

Choi, Kyoungah; Lee, Impyeong

2015-01-01

We propose a novel approach to evaluating how effectively a closed circuit television (CCTV) system can monitor a targeted area. With 3D models of the target area and the camera parameters of the CCTV system, the approach produces surveillance coverage index, which is newly defined in this study as a quantitative measure for surveillance performance. This index indicates the proportion of the space being monitored with a sufficient resolution to the entire space of the target area. It is determined by computing surveillance resolution at every position and orientation, which indicates how closely a specific object can be monitored with a CCTV system. We present full mathematical derivation for the resolution, which depends on the location and orientation of the object as well as the geometric model of a camera. With the proposed approach, we quantitatively evaluated the surveillance coverage of a CCTV system in an underground parking area. Our evaluation process provided various quantitative-analysis results, compelling us to examine the design of the CCTV system prior to its installation and understand the surveillance capability of an existing CCTV system. PMID:26389909

Strategic Orientation in the Globalization of Software Firms

NASA Astrophysics Data System (ADS)

Dedrick, Jason; Kraemer, Kenneth L.; Carmel, Erran; Dunkle, Debora

In the search for profits, software firms are globalizing their development activities. Some firms achieve greater profits by becoming more efficient, whereas others do so by reaching new markets; some do both. This paper creates an a priori typology of strategies based on the extent to which firms are focused on operational improvement or market access, have a dual focus or are unfocused. We find that firms with these strategies differ in degree of internationalization, organization of offshoring and performance outcomes related to offshoring. Market-oriented firms receive a greater proportion of their total revenue from sales outside the U.S., showing a greater international orientation. They keep more of their offshore development in-house via captive operations. They also are most likely to report increased non-U.S. sales as a result of offshoring. On the other hand, operations-oriented firms have lower levels of international sales, are more likely to go offshore via outsourced software development, and achieve greater costs savings and labor force flexibility as a result of offshoring. Operations-oriented firms also face more obstacles in offshoring, perhaps because of their reliance on outsourcing. Dual focus firms generally achieve some of the best of both strategies, whereas unfocused firms achieve lower cost benefits.

Investigating the intrinsic and extrinsic work values of 10th grade students in science-oriented charter schools

NASA Astrophysics Data System (ADS)

Ozer, Ozgur

The purpose of this study was to investigate to what extent gender, achievement level, and income level predict the intrinsic and extrinsic work values of 10th grade students. The study explored whether group differences were good predictors of scores in work values. The research was a descriptive, cross-sectional study conducted on 131 10th graders who attended science-oriented charter schools. Students took Super's Work Values Instrument, a Likert-type test that links to 15 work values, which can be categorized as intrinsic and extrinsic values (Super, 1970). Multiple regression analysis was employed as the main analysis followed by ANCOVA. Multiple regression analysis results indicated that there is evidence that 8.9% of the variance in intrinsic work values and 10.2% of the variance in extrinsic work values can be explained by the independent variables ( p < .05). Achievement Level and Income Level may help predict intrinsic work value scores; Achievement Level may also help predict extrinsic work values. Achievement Level was the covariate in ANCOVA. Results indicated that males (M = .174) in this sample have a higher mean of extrinsic work values than that of females (M = -.279). However, there was no statistically significant difference between the intrinsic work values by gender. One possible interpretation of this might be school choice; students in these science-oriented charter schools may have higher intrinsic work values regardless of gender. Results indicated that there was no statistically significant difference among the means of extrinsic work values by income level (p < .05). However, free lunch students (M = .268) have a higher mean of intrinsic work values than that of paid lunch students ( M = -.279). A possible interpretation of this might be that lower income students benefit greatly from the intrinsic work values in overcoming obstacles. Further research is needed in each of these areas. The study produced statistically significant results with little practical significance. Students, parents, teachers, and counselors may still be advised to consider the work value orientations of students during the career choice process.

D Animation Reconstruction from Multi-Camera Coordinates Transformation

NASA Astrophysics Data System (ADS)

Jhan, J. P.; Rau, J. Y.; Chou, C. M.

2016-06-01

Reservoir dredging issues are important to extend the life of reservoir. The most effective and cost reduction way is to construct a tunnel to desilt the bottom sediment. Conventional technique is to construct a cofferdam to separate the water, construct the intake of tunnel inside and remove the cofferdam afterwards. In Taiwan, the ZengWen reservoir dredging project will install an Elephant-trunk Steel Pipe (ETSP) in the water to connect the desilting tunnel without building the cofferdam. Since the installation is critical to the whole project, a 1:20 model was built to simulate the installation steps in a towing tank, i.e. launching, dragging, water injection, and sinking. To increase the construction safety, photogrammetry technic is adopted to record images during the simulation, compute its transformation parameters for dynamic analysis and reconstruct the 4D animations. In this study, several Australiscoded targets are fixed on the surface of ETSP for auto-recognition and measurement. The cameras orientations are computed by space resection where the 3D coordinates of coded targets are measured. Two approaches for motion parameters computation are proposed, i.e. performing 3D conformal transformation from the coordinates of cameras and relative orientation computation by the orientation of single camera. Experimental results show the 3D conformal transformation can achieve sub-mm simulation results, and relative orientation computation shows the flexibility for dynamic motion analysis which is easier and more efficiency.

Transcriptional Analysis of a Whole-Body Form of Long-Term Habituation in "Aplysia Californica"

ERIC Educational Resources Information Center

Holmes, Geraldine; Herdegen, Samantha; Schuon, Jonathan; Cyriac, Ashly; Lass, Jamie; Conte, Catherine; Calin-Jageman, Irina E.; Calin-Jageman, Robert J.

2015-01-01

Habituation is the simplest form of learning, but we know little about the transcriptional mechanisms that encode long-term habituation memory. A key obstacle is that habituation is relatively stimulus-specific and is thus encoded in small sets of neurons, providing poor signal/noise ratios for transcriptional analysis. To overcome this obstacle,…

miR-340 alleviates chemoresistance of osteosarcoma cells by targeting ZEB1.

PubMed

Yan, Haibin; Zhang, Bingyun; Fang, Chongbin; Chen, Liqiu

2018-06-01

Chemoresistance during treatment of osteosarcoma (OS) is attracting more and more attention as the main clinical obstacle. The purpose of this study was to elucidate the role of miR-340 in chemoresistance of OS. Plasmid construction and transfection, miRNA arrays, PCR analyses, and western blot analysis, as well as MTT, apoptosis, and luciferase assays were carried out in MG-63 cells and MG-63/cisplatin (DDP)-resistant cells. The results showed that miR-340 was downregulated in OS tissues and drug-resistant OS cells. Moreover, a negative correlation was observed between miR-340 and ZEB1 expression in OS tissues. Forced expression of miR-340 in drug-resistant OS cells significantly reduced multidrug resistance-1 and P-gp expression. Overexpression of miR-340 enhanced sensitivity to DDP by inhibiting viability and promoting apoptosis. The luciferase assay and western blot analysis identified ZEB1 as a direct target of miR-340, and miR-340 negatively regulated ZEB1 expression. Ectopic expression of ZEB1 reversed the effects of miR-340 on P-gp expression, cell viability, and apoptosis. miR-340 alleviated chemoresistance of OS cells by targeting ZEB1. Our results indicate that targeting miR-340 may be a potential therapeutic approach to treat drug-resistant OS.

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.

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.

The Study of Intelligent Vehicle Navigation Path Based on Behavior Coordination of Particle Swarm.

PubMed

Han, Gaining; Fu, Weiping; Wang, Wen

2016-01-01

In the behavior dynamics model, behavior competition leads to the shock problem of the intelligent vehicle navigation path, because of the simultaneous occurrence of the time-variant target behavior and obstacle avoidance behavior. Considering the safety and real-time of intelligent vehicle, the particle swarm optimization (PSO) algorithm is proposed to solve these problems for the optimization of weight coefficients of the heading angle and the path velocity. Firstly, according to the behavior dynamics model, the fitness function is defined concerning the intelligent vehicle driving characteristics, the distance between intelligent vehicle and obstacle, and distance of intelligent vehicle and target. Secondly, behavior coordination parameters that minimize the fitness function are obtained by particle swarm optimization algorithms. Finally, the simulation results show that the optimization method and its fitness function can improve the perturbations of the vehicle planning path and real-time and reliability.

Handedness helps homing in swimming and flying animals.

PubMed

Bandyopadhyay, Promode R; Leinhos, Henry A; Hellum, Aren M

2013-01-01

Swimming and flying animals rely on their ability to home on mobile targets. In some fish, physiological handedness and homing correlate, and dolphins exhibit handedness in their listening response. Here, we explore theoretically whether the actuators, sensors, and controllers in these animals follow similar laws of self-regulation, and how handedness affects homing. We find that the acoustic sensor (combined hydrophone-accelerometer) response maps are similar to fin force maps-modeled by Stuart-Landau oscillators-allowing localization by transitional vortex-propelled animals. The planar trajectories of bats in a room filled with obstacles are approximately reproduced by the states of a pair of strong and weak olivo-cerebellar oscillators. The stereoscopy of handedness reduces ambiguity near a mobile target, resulting in accelerated homing compared to even-handedness. Our results demonstrate how vortex-propelled animals may be localizing each other and circumventing obstacles in changing environments. Handedness could be useful in time-critical robot-assisted rescues in hazardous environments.

The Study of Intelligent Vehicle Navigation Path Based on Behavior Coordination of Particle Swarm

PubMed Central

Han, Gaining; Fu, Weiping; Wang, Wen

2016-01-01

In the behavior dynamics model, behavior competition leads to the shock problem of the intelligent vehicle navigation path, because of the simultaneous occurrence of the time-variant target behavior and obstacle avoidance behavior. Considering the safety and real-time of intelligent vehicle, the particle swarm optimization (PSO) algorithm is proposed to solve these problems for the optimization of weight coefficients of the heading angle and the path velocity. Firstly, according to the behavior dynamics model, the fitness function is defined concerning the intelligent vehicle driving characteristics, the distance between intelligent vehicle and obstacle, and distance of intelligent vehicle and target. Secondly, behavior coordination parameters that minimize the fitness function are obtained by particle swarm optimization algorithms. Finally, the simulation results show that the optimization method and its fitness function can improve the perturbations of the vehicle planning path and real-time and reliability. PMID:26880881

Determinants of Benin elementary school science teachers' orientation toward inquiry-based instructional practices

NASA Astrophysics Data System (ADS)

Gado, Issaou

The Republic of Benin (West Africa) undertook a nationwide curriculum reform that put an emphasis on inquiry-based instructional practices. Little, if any, research has been conducted to explore factors that could be related to teachers' orientation toward inquiry instructional practices. The purpose of this research study was to investigate factors and concerns that determine Benin elementary school teachers' orientation toward the use of inquiry-based instruction in the teaching of science. The study followed a naturalistic inquiry methodology combining a correlational ex post facto design and an observational case-study design. The theory of Planned Behavior was the conceptual framework used to design the study. Two hundred (N = 200) elementary school teachers and three (n = 3) case study participants were purposively selected. Data was gathered via the Revised Science Attitude Scale (Thompson & Shrigley, 1986), the Science Teachers' Ideological Preference Scale (Jones & Harty, 1978), open-ended questions, interviews, and classroom observations using audiorecorders, videorecorders, and the researcher-contextualized version of the Observational System for the Analysis of Classroom Instruction (Hough, 1966). Qualitative and quantitative data provided a deeper understanding of participants' responses. Quantitative measures indicated that Benin elementary school teachers have positive attitudes toward school science, significant positive orientation toward both inquiry-based instruction and traditional non inquiry-based instruction, and higher orientation toward inquiry-based instruction than traditional non inquiry-based instruction. Attitude toward handling materials for investigations was found to significantly contribute to the prediction of participants' inquiry orientation. Qualitative analyses of participants' responses indicated that the expectations of educational leaders, individual motivation to comply with the program, a perceived control of the performance of inquiry-based activities, students' inquiry outcome expectancy or likelihood of occurrence in the classroom, the pedagogical structure of the program, and the student-centeredness of the program were potential motivational factors that could explain participants' orientation toward inquiry-based instruction. Four major concerns---lack of materials for teaching, lack of training in the process and strategy of inquiry, overloaded curriculum content, students' linguistic difficulties---were perceived obstacles in implementing inquiry-based instruction. Implications for transformative curriculum practices are discussed.

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.

On the Magnitude and Orientation of Stress during Shock Metamorphism: Understanding Peak Ring Formation by Combining Observations and Models.

NASA Astrophysics Data System (ADS)

Rae, A.; Poelchau, M.; Collins, G. S.; Timms, N.; Cavosie, A. J.; Lofi, J.; Salge, T.; Riller, U. P.; Ferrière, L.; Grieve, R. A. F.; Osinski, G.; Morgan, J. V.; Expedition 364 Science Party, I. I.

2017-12-01

Shock metamorphism occurs during the earliest moments after impact. The magnitude and orientation of shock leaves recordable signatures in rocks, which spatially vary across an impact structure. Consequently, observations of shock metamorphism can be used to understand deformation and its history within a shock wave, and to examine subsequent deformation during crater modification. IODP-ICDP Expedition 364 recovered nearly 600 m of shocked target rocks from the peak ring of the Chicxulub Crater. Samples from the expedition were used to measure the magnitude and orientation of shock in peak ring materials, and to determine the mechanism of peak-ring emplacement. Here, we present the results of petrographic analyses of the shocked granitic target rocks of the Chicxulub peak ring; using universal-stage optical microscopy, back-scattered electron images, and electron back-scatter diffraction. Deformation microstructures in quartz include planar deformation features (PDFs), feather features (FFs), which are unique to shock conditions, as well as planar fractures and crystal-plastic deformation bands. The assemblage of PDFs in quartz suggest that the peak-ring rocks experienced shock pressures of 15 GPa throughout the recovered drill core, and that the orientation of FFs are consistent with the present-day orientation of the maximum principal stress direction during shock is close to vertical. Numerical impact simulations of the impact event were run to determine the magnitude and orientation of principal stresses during shock and track those orientations throughout crater formation. Our results are remarkably consistent with the geological data, and accurately predict both the shock-pressure magnitudes, and the final near-vertical orientation of the direction of maximum principal stress in the shock wave. Furthermore, analysis of the state of stress throughout the impact event can be used to constrain the timing of fracture and fault orientations observed in the core. Our results quantitatively describe the deviatoric stress conditions of rocks in shock, which are consistent with observations of shock deformation. Our integrated analysis provides further support for the dynamic collapse model of peak-ring formation, and places dynamic constraints on the conditions of peak-ring formation.

Pre-saccadic perception: Separate time courses for enhancement and spatial pooling at the saccade target

PubMed Central

Buonocore, Antimo; Fracasso, Alessio; Melcher, David

2017-01-01

We interact with complex scenes using eye movements to select targets of interest. Studies have shown that the future target of a saccadic eye movement is processed differently by the visual system. A number of effects have been reported, including a benefit for perceptual performance at the target (“enhancement”), reduced influences of backward masking (“un-masking”), reduced crowding (“un-crowding”) and spatial compression towards the saccade target. We investigated the time course of these effects by measuring orientation discrimination for targets that were spatially crowded or temporally masked. In four experiments, we varied the target-flanker distance, the presence of forward/backward masks, the orientation of the flankers and whether participants made a saccade. Masking and randomizing flanker orientation reduced performance in both fixation and saccade trials. We found a small improvement in performance on saccade trials, compared to fixation trials, with a time course that was consistent with a general enhancement at the saccade target. In addition, a decrement in performance (reporting the average flanker orientation, rather than the target) was found in the time bins nearest saccade onset when random oriented flankers were used, consistent with spatial pooling around the saccade target. We did not find strong evidence for un-crowding. Overall, our pattern of results was consistent with both an early, general enhancement at the saccade target and a later, peri-saccadic compression/pooling towards the saccade target. PMID:28614367

MSN anti-cancer nanomedicines: chemotherapy enhancement, overcoming of drug resistance, and metastasis inhibition.

PubMed

He, Qianjun; Shi, Jianlin

2014-01-22

In the anti-cancer war, there are three main obstacles resulting in high mortality and recurrence rate of cancers: the severe toxic side effect of anti-cancer drugs to normal tissues due to the lack of tumor-selectivity, the multi-drug resistance (MDR) to free chemotherapeutic drugs and the deadly metastases of cancer cells. The development of state-of-art nanomedicines based on mesoporous silica nanoparticles (MSNs) is expected to overcome the above three main obstacles. In the view of the fast development of anti-cancer strategy, this review highlights the most recent advances of MSN anti-cancer nanomedicines in enhancing chemotherapeutic efficacy, overcoming the MDR and inhibiting metastasis. Furthermore, we give an outlook of the future development of MSNs-based anti-cancer nanomedicines, and propose several innovative and forward-looking anti-cancer strategies, including tumor tissue-cell-nuclear successionally targeted drug delivery strategy, tumor cell-selective nuclear-targeted drug delivery strategy, multi-targeting and multi-drug strategy, chemo-/radio-/photodynamic-/ultrasound-/thermo-combined multi-modal therapy by virtue of functionalized hollow/rattle-structured MSNs. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Training addiction professionals in empirically supported treatments: perspectives from the treatment community.

PubMed

Hartzler, Bryan; Rabun, Carl

2014-01-01

Large-scale dissemination efforts seek to expand opportunities for the addiction treatment community to receive training in empirically supported treatments (ESTs). Prospective consumers of such training are valuable sources of input about content of interest, preferences for how training events are structured, and obstacles that deter receipt of training. In this mixed-method study, data were collected in 64 semistructured individual interviews with personnel during site visits to 16 community opioid treatment programs (OTPs). At each OTP, interviews were completed with the executive director, a clinical supervisor, and 2 direct-service clinicians. Topical interests were analyzed qualitatively in a cultural domain analysis. Likert ratings of training event preferences were analyzed via generalized linear mixed models (GLMMs), and unstructured interviewee comments were analyzed via narrative analysis. Obstacles to training receipt were analyzed qualitatively with both content coding and narrative analysis. Based on topics of reported interest, cultural domain analysis suggests as ESTs of note: Multidimensional Family Therapy, Motivational Enhancement Therapy, Relapse Prevention Therapy, "Seeking Safety," and broad addiction-focused pharmacotherapy. Regarding training event preferences, GLMMs and narrative analysis revealed clear preferences for time-distributed trainings and use of participatory activities (e.g., trainer demonstrations, role plays, small group exercises). Content coding identified cost as the primary obstacle to receipt of EST trainings, followed by lack of time, logistical challenges, and disinterest, and narrative analysis elaborated on contextual issues underlying these obstacles. As primary consumers of EST technologies, the treatment community has valuable input to offer. Dissemination efforts may be enhanced by greater consideration of their preferences for training content and event structure, as well as practical obstacles that challenge their receipt of training.

Endogenous orienting in the archer fish.

PubMed

Saban, William; Sekely, Liora; Klein, Raymond M; Gabay, Shai

2017-07-18

The literature has long emphasized the neocortex's role in volitional processes. In this work, we examined endogenous orienting in an evolutionarily older species, the archer fish, which lacks neocortex-like cells. We used Posner's classic endogenous cuing task, in which a centrally presented, spatially informative cue is followed by a target. The fish responded to the target by shooting a stream of water at it. Interestingly, the fish demonstrated a human-like "volitional" facilitation effect: their reaction times to targets that appeared on the side indicated by the precue were faster than their reaction times to targets on the opposite side. The fish also exhibited inhibition of return, an aftermath of orienting that commonly emerges only in reflexive orienting tasks in human participants. We believe that this pattern demonstrates the acquisition of an arbitrary connection between spatial orienting and a nonspatial feature of a centrally presented stimulus in nonprimate species. In the literature on human attention, orienting in response to such contingencies has been strongly associated with volitional control. We discuss the implications of these results for the evolution of orienting, and for the study of volitional processes in all species, including humans.

Magnetic Field Observations near Venus: Preliminary Results from Mariner 10.

PubMed

Ness, N F; Behannon, K W; Lepping, R P; Whang, Y C; Schatten, K H

1974-03-29

The NASA-GSFC magnetic field experiment on Mariner 10 is the first flight of a dual magnetometer system conceived to permit accurate measurements of weak magnetic fields in space in the presence of a significant and variable spacecraft magnetic field. Results from a preliminary analysis of a limted data set are summarized in this report, which is restricted primarily to Venus encounter. A detached bow shock wave that develops as the super Alfvénic solar wind interacts with the Venusian atmosphere has been observed. However, the unique coincidence of trajectory position and interplanetary field orientation at the time of bow shock crossing led to a very disturbed shock profile with considerably enhanced upstream magnetic fluctuations. At present it is not possible to ascertain the nature and characteristics of the obstacle responsible for deflecting the solar wind flow. Far downstream disturbances associated with the solar wind wake have been observed.

Cross-orientation interactions in human vision.

PubMed

Roeber, Urte; Wong, Elaine M Y; Freeman, Alan W

2008-03-18

Humans can discriminate one visual contour from another on the basis of small differences in orientation. This capability depends on cortical detectors that are selective for a small range of orientations. We have measured this orientation bandwidth and the suppression that helps to shape it, with a reverse correlation technique. Human subjects were presented with a stream of randomly oriented gratings at a rate of 30 per second. Their task was to press a key whenever they saw an orientation nominated as the target. We analyzed the data by finding the probability density of two orientations: One preceded the key-press by the reaction time, and the second preceded the first by up to 100 ms. The results were as follows: (1) One grating facilitated the following one in producing a key-press when the gratings differed little in orientation. The estimate of orientation bandwidth resulting from this facilitation was 38 degrees . (2) A large angle between the two orientations reduced the probability of a key-press. This finding was best modelled as a suppression that did not vary with orientation, consistent with the idea that cross-orientation suppression is non-oriented. (3) Analysis of non-consecutive grating pairs showed that cross-orientation interactions lasted no longer than 67 ms.

Effect of cane length and swing arc width on drop-off and obstacle detection with the long cane

PubMed Central

Kim, Dae Shik; Emerson, Robert Wall; Naghshineh, Koorosh

2017-01-01

A repeated-measures design with block randomization was used for the study, in which 15 adults with visual impairments attempted to detect the drop-offs and obstacles with the canes of different lengths, swinging the cane in different widths (narrow vs wide). Participants detected the drop-offs significantly more reliably with the standard-length cane (79.5% ± 6.5% of the time) than with the extended-length cane (67.6% ± 9.1%), p <.001. The drop-off detection threshold of the standard-length cane (4.1 ± 1.1 cm) was also significantly smaller than that of the extended-length cane (6.5±1.8cm), p <.001. In addition, participants detected drop-offs at a significantly higher percentage when they swung the cane approximately 3 cm beyond the widest part of the body (78.6% ± 7.6%) than when they swung it substantially wider (30 cm; 68.5% ± 8.3%), p <.001. In contrast, neither cane length (p =.074) nor cane swing arc width (p =.185) had a significant effect on obstacle detection performance. The findings of the study may help orientation and mobility specialists recommend appropriate cane length and cane swing arc width to visually impaired cane users. PMID:29276326

Waist-up protection for blind individuals using the EyeCane as a primary and secondary mobility aid.

PubMed

Buchs, Galit; Simon, Noa; Maidenbaum, Shachar; Amedi, Amir

2017-01-01

One of the most stirring statistics in relation to the mobility of blind individuals is the high rate of upper body injuries, even when using the white-cane. We here addressed a rehabilitation- oriented challenge of providing a reliable tool for blind people to avoid waist-up obstacles, namely one of the impediments to their successful mobility using currently available methods (e.g., white-cane). We used the EyeCane, a device we developed which translates distances from several angles to haptic and auditory cues in an intuitive and unobtrusive manner, serving both as a primary and secondary mobility aid. We investigated the rehabilitation potential of such a device in facilitating visionless waist-up body protection. After ∼5 minutes of training with the EyeCane blind participants were able to successfully detect and avoid obstacles waist-high and up. This was significantly higher than their success when using the white-cane alone. As avoidance of obstacles required participants to perform an additional cognitive process after their detection, the avoidance rate was significantly lower than the detection rate. Our work has demonstrated that the EyeCane has the potential to extend the sensory world of blind individuals by expanding their currently accessible inputs, and has offered them a new practical rehabilitation tool.

Effect of cane length and swing arc width on drop-off and obstacle detection with the long cane.

PubMed

Kim, Dae Shik; Emerson, Robert Wall; Naghshineh, Koorosh

2017-09-01

A repeated-measures design with block randomization was used for the study, in which 15 adults with visual impairments attempted to detect the drop-offs and obstacles with the canes of different lengths, swinging the cane in different widths (narrow vs wide). Participants detected the drop-offs significantly more reliably with the standard-length cane (79.5% ± 6.5% of the time) than with the extended-length cane (67.6% ± 9.1%), p <.001. The drop-off detection threshold of the standard-length cane (4.1 ± 1.1 cm) was also significantly smaller than that of the extended-length cane (6.5±1.8cm), p <.001. In addition, participants detected drop-offs at a significantly higher percentage when they swung the cane approximately 3 cm beyond the widest part of the body (78.6% ± 7.6%) than when they swung it substantially wider (30 cm; 68.5% ± 8.3%), p <.001. In contrast, neither cane length ( p =.074) nor cane swing arc width ( p =.185) had a significant effect on obstacle detection performance. The findings of the study may help orientation and mobility specialists recommend appropriate cane length and cane swing arc width to visually impaired cane users.

Ray splitting in the reflection and refraction of surface acoustic waves in anisotropic solids.

PubMed

Every, A G; Maznev, A A

2010-05-01

This paper examines the conditions for, and provides examples of, ray splitting in the reflection and refraction of surface acoustic waves (SAW) in elastically anisotropic solids at straight obstacles such as edges, surface breaking cracks, and interfaces between different solids. The concern here is not with the partial scattering of an incident SAW's energy into bulk waves, but with the occurrence of more than one SAW ray in the reflected and/or transmitted wave fields, by analogy with birefringence in optics and mode conversion of bulk elastic waves at interfaces. SAW ray splitting is dependent on the SAW slowness curve possessing concave regions, which within the constraint of wave vector conservation parallel to the obstacle allows multiple outgoing SAW modes for certain directions of incidence and orientation of obstacle. The existence of pseudo-SAW for a given surface provides a further channel for ray splitting. This paper discusses some typical material configurations for which SAW ray splitting occurs. An example is provided of mode conversion entailing backward reflection or negative refraction. Experimental demonstration of ray splitting in the reflection of a laser generated SAW in GaAs(111) is provided. The calculation of SAW mode conversion amplitudes lies outside the scope of this paper.

Enabling UAV Navigation with Sensor and Environmental Uncertainty in Cluttered and GPS-Denied Environments

PubMed Central

Vanegas, Fernando; Gonzalez, Felipe

2016-01-01

Unmanned Aerial Vehicles (UAV) can navigate with low risk in obstacle-free environments using ground control stations that plan a series of GPS waypoints as a path to follow. This GPS waypoint navigation does however become dangerous in environments where the GPS signal is faulty or is only present in some places and when the airspace is filled with obstacles. UAV navigation then becomes challenging because the UAV uses other sensors, which in turn generate uncertainty about its localisation and motion systems, especially if the UAV is a low cost platform. Additional uncertainty affects the mission when the UAV goal location is only partially known and can only be discovered by exploring and detecting a target. This navigation problem is established in this research as a Partially-Observable Markov Decision Process (POMDP), so as to produce a policy that maps a set of motion commands to belief states and observations. The policy is calculated and updated on-line while flying with a newly-developed system for UAV Uncertainty-Based Navigation (UBNAV), to navigate in cluttered and GPS-denied environments using observations and executing motion commands instead of waypoints. Experimental results in both simulation and real flight tests show that the UAV finds a path on-line to a region where it can explore and detect a target without colliding with obstacles. UBNAV provides a new method and an enabling technology for scientists to implement and test UAV navigation missions with uncertainty where targets must be detected using on-line POMDP in real flight scenarios. PMID:27171096

Enabling UAV Navigation with Sensor and Environmental Uncertainty in Cluttered and GPS-Denied Environments.

PubMed

Vanegas, Fernando; Gonzalez, Felipe

2016-05-10

Unmanned Aerial Vehicles (UAV) can navigate with low risk in obstacle-free environments using ground control stations that plan a series of GPS waypoints as a path to follow. This GPS waypoint navigation does however become dangerous in environments where the GPS signal is faulty or is only present in some places and when the airspace is filled with obstacles. UAV navigation then becomes challenging because the UAV uses other sensors, which in turn generate uncertainty about its localisation and motion systems, especially if the UAV is a low cost platform. Additional uncertainty affects the mission when the UAV goal location is only partially known and can only be discovered by exploring and detecting a target. This navigation problem is established in this research as a Partially-Observable Markov Decision Process (POMDP), so as to produce a policy that maps a set of motion commands to belief states and observations. The policy is calculated and updated on-line while flying with a newly-developed system for UAV Uncertainty-Based Navigation (UBNAV), to navigate in cluttered and GPS-denied environments using observations and executing motion commands instead of waypoints. Experimental results in both simulation and real flight tests show that the UAV finds a path on-line to a region where it can explore and detect a target without colliding with obstacles. UBNAV provides a new method and an enabling technology for scientists to implement and test UAV navigation missions with uncertainty where targets must be detected using on-line POMDP in real flight scenarios.

Asymptotically Optimal Motion Planning for Learned Tasks Using Time-Dependent Cost Maps

PubMed Central

Bowen, Chris; Ye, Gu; Alterovitz, Ron

2015-01-01

In unstructured environments in people’s homes and workspaces, robots executing a task may need to avoid obstacles while satisfying task motion constraints, e.g., keeping a plate of food level to avoid spills or properly orienting a finger to push a button. We introduce a sampling-based method for computing motion plans that are collision-free and minimize a cost metric that encodes task motion constraints. Our time-dependent cost metric, learned from a set of demonstrations, encodes features of a task’s motion that are consistent across the demonstrations and, hence, are likely required to successfully execute the task. Our sampling-based motion planner uses the learned cost metric to compute plans that simultaneously avoid obstacles and satisfy task constraints. The motion planner is asymptotically optimal and minimizes the Mahalanobis distance between the planned trajectory and the distribution of demonstrations in a feature space parameterized by the locations of task-relevant objects. The motion planner also leverages the distribution of the demonstrations to significantly reduce plan computation time. We demonstrate the method’s effectiveness and speed using a small humanoid robot performing tasks requiring both obstacle avoidance and satisfaction of learned task constraints. Note to Practitioners Motivated by the desire to enable robots to autonomously operate in cluttered home and workplace environments, this paper presents an approach for intuitively training a robot in a manner that enables it to repeat the task in novel scenarios and in the presence of unforeseen obstacles in the environment. Based on user-provided demonstrations of the task, our method learns features of the task that are consistent across the demonstrations and that we expect should be repeated by the robot when performing the task. We next present an efficient algorithm for planning robot motions to perform the task based on the learned features while avoiding obstacles. We demonstrate the effectiveness of our motion planner for scenarios requiring transferring a powder and pushing a button in environments with obstacles, and we plan to extend our results to more complex tasks in the future. PMID:26279642

The solar cycle dependence of the location and shape of the Venus bow shock

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

Zhang, T.L.; Luhmann, J.G.; Russell, C.T.

1990-09-01

From initial Pioneer Venus observations during the maximum of solar cycle 21 it was evident that the position of the Venus bow shock varies with solar activity. The bow shock radius in the terminator plane changed from 2.4 R{sub v} to 2.1 R{sub v} as solar activity went from maximum to minimum and, as activity has increased in cycle 22, it has increased again. The recent studies of the subsolar region show that the altitude of the nose of the bow shock varies from 1,600 km at solar minimum to 2,200 km at intermediate solar activity in concert with themore » terminator altitude so that the shape remains constant and only the size varies during the solar cycle. Using a gas dynamic model and the observed bow shock location, the authors infer the variation in the size of the effective obstacle during the solar cycle. At solar maximum, the effective obstacle is larger than the ionopause as if a magnetic barrier exists in the inner magnetosheath. This magnetic barrier acts as the effective obstacle deflecting the magnetosheath plasma about 500 km above the surface of Venus. However, at solar minimum the effective obstacle is well below the subsolar ionopause, and some absorption of the solar wind plasma by the Venus neutral atmosphere is suggested by these observations. The dependence of the solar cycle variation of the shock position on the orientation of the interplanetary magnetic field reinforces the idea that planetary ion pickup is important in the interaction of the solar wind with Venus.« less

Distributed flow estimation and closed-loop control of an underwater vehicle with a multi-modal artificial lateral line.

PubMed

DeVries, Levi; Lagor, Francis D; Lei, Hong; Tan, Xiaobo; Paley, Derek A

2015-03-25

Bio-inspired sensing modalities enhance the ability of autonomous vehicles to characterize and respond to their environment. This paper concerns the lateral line of cartilaginous and bony fish, which is sensitive to fluid motion and allows fish to sense oncoming flow and the presence of walls or obstacles. The lateral line consists of two types of sensing modalities: canal neuromasts measure approximate pressure gradients, whereas superficial neuromasts measure local flow velocities. By employing an artificial lateral line, the performance of underwater sensing and navigation strategies is improved in dark, cluttered, or murky environments where traditional sensing modalities may be hindered. This paper presents estimation and control strategies enabling an airfoil-shaped unmanned underwater vehicle to assimilate measurements from a bio-inspired, multi-modal artificial lateral line and estimate flow properties for feedback control. We utilize potential flow theory to model the fluid flow past a foil in a uniform flow and in the presence of an upstream obstacle. We derive theoretically justified nonlinear estimation strategies to estimate the free stream flowspeed, angle of attack, and the relative position of an upstream obstacle. The feedback control strategy uses the estimated flow properties to execute bio-inspired behaviors including rheotaxis (the tendency of fish to orient upstream) and station-holding (the tendency of fish to position behind an upstream obstacle). A robotic prototype outfitted with a multi-modal artificial lateral line composed of ionic polymer metal composite and embedded pressure sensors experimentally demonstrates the distributed flow sensing and closed-loop control strategies.

Characteristics of functional enrichment and gene expression level of human putative transcriptional target genes.

PubMed

Osato, Naoki

2018-01-19

Transcriptional target genes show functional enrichment of genes. However, how many and how significantly transcriptional target genes include functional enrichments are still unclear. To address these issues, I predicted human transcriptional target genes using open chromatin regions, ChIP-seq data and DNA binding sequences of transcription factors in databases, and examined functional enrichment and gene expression level of putative transcriptional target genes. Gene Ontology annotations showed four times larger numbers of functional enrichments in putative transcriptional target genes than gene expression information alone, independent of transcriptional target genes. To compare the number of functional enrichments of putative transcriptional target genes between cells or search conditions, I normalized the number of functional enrichment by calculating its ratios in the total number of transcriptional target genes. With this analysis, native putative transcriptional target genes showed the largest normalized number of functional enrichments, compared with target genes including 5-60% of randomly selected genes. The normalized number of functional enrichments was changed according to the criteria of enhancer-promoter interactions such as distance from transcriptional start sites and orientation of CTCF-binding sites. Forward-reverse orientation of CTCF-binding sites showed significantly higher normalized number of functional enrichments than the other orientations. Journal papers showed that the top five frequent functional enrichments were related to the cellular functions in the three cell types. The median expression level of transcriptional target genes changed according to the criteria of enhancer-promoter assignments (i.e. interactions) and was correlated with the changes of the normalized number of functional enrichments of transcriptional target genes. Human putative transcriptional target genes showed significant functional enrichments. Functional enrichments were related to the cellular functions. The normalized number of functional enrichments of human putative transcriptional target genes changed according to the criteria of enhancer-promoter assignments and correlated with the median expression level of the target genes. These analyses and characters of human putative transcriptional target genes would be useful to examine the criteria of enhancer-promoter assignments and to predict the novel mechanisms and factors such as DNA binding proteins and DNA sequences of enhancer-promoter interactions.

Analysis of structure and deformation behavior of AISI 316L tensile specimens from the second operational target module at the Spallation Neutron Source

DOE PAGES

Gussev, Maxim N.; McClintock, David A.; Garner, Frank

2015-08-05

In an earlier publication, tensile testing was performed on specimens removed from the first two operational targets of the Spallation Neutron Source (SNS). There were several anomalous features in the results. First, some specimens had very large elongations (up to 57%) while others had significantly smaller values. Second, there was a larger than the usual amount of data scatter in the elongation results. Third, the stress-strain diagrams of nominally similar specimens spanned a wide range of behavior ranging from expected irradiation-induced hardening to varying levels of force drop after yield point and indirect signs of "traveling deformation wave" behavior associatedmore » with strain-induced martensite formation. To investigate the cause(s) of such variable tensile behavior, several specimens from Target 2, spanning the range of observed tensile behavior, were chosen for detailed microstructural examination using electron backscattering analysis (EBSD). It was also shown that the steel employed in the construction of the target contained an unexpected bimodal grain size distribution, containing very large out-of-specification grains surrounded by necklaces of grains of within-specification sizes. The large grains were frequently comparable to the width of the gauge section of the tensile specimen. Moreover, the propensity to form martensite during deformation was shown to be accelerated by radiation but also to be very sensitive to the relative orientation of the grains with respect to the tensile axis. Specimens having large grains in the gauge that were most favorably oriented for production of martensite strongly exhibited the traveling deformation wave phenomenon, while those specimens with less favorably oriented grains had lesser or no degree of the wave effect, thereby accounting for the larger than expected data scatter.« less

Towards an organisation-wide process-oriented organisation of care: A literature review

PubMed Central

2011-01-01

Background Many hospitals have taken actions to make care delivery for specific patient groups more process-oriented, but struggle with the question how to deal with process orientation at hospital level. The aim of this study is to report and discuss the experiences of hospitals with implementing process-oriented organisation designs in order to derive lessons for future transitions and research. Methods A literature review of English language articles on organisation-wide process-oriented redesigns, published between January 1998 and May 2009, was performed. Results Of 329 abstracts identified, 10 articles were included in the study. These articles described process-oriented redesigns of five hospitals. Four hospitals tried to become process-oriented by the implementation of coordination measures, and one by organisational restructuring. The adoption of the coordination mechanism approach was particularly constrained by the functional structure of hospitals. Other factors that hampered the redesigns in general were the limited applicability of and unfamiliarity with process improvement techniques. Conclusions Due to the limitations of the evidence, it is not known which approach, implementation of coordination measures or organisational restructuring (with additional coordination measures), produces the best results in which situation. Therefore, more research is needed. For this research, the use of qualitative methods in addition to quantitative measures is recommended to contribute to a better understanding of preconditions and contingencies for an effective application of approaches to become process-oriented. Hospitals are advised to take the factors for failure described into account and to take suitable actions to counteract these obstacles on their way to become process-oriented organisations. PMID:21247491

Towards an organisation-wide process-oriented organisation of care: a literature review.

PubMed

Vos, Leti; Chalmers, Sarah E; Dückers, Michel La; Groenewegen, Peter P; Wagner, Cordula; van Merode, Godefridus G

2011-01-19

Many hospitals have taken actions to make care delivery for specific patient groups more process-oriented, but struggle with the question how to deal with process orientation at hospital level. The aim of this study is to report and discuss the experiences of hospitals with implementing process-oriented organisation designs in order to derive lessons for future transitions and research. A literature review of English language articles on organisation-wide process-oriented redesigns, published between January 1998 and May 2009, was performed. Of 329 abstracts identified, 10 articles were included in the study. These articles described process-oriented redesigns of five hospitals. Four hospitals tried to become process-oriented by the implementation of coordination measures, and one by organisational restructuring. The adoption of the coordination mechanism approach was particularly constrained by the functional structure of hospitals. Other factors that hampered the redesigns in general were the limited applicability of and unfamiliarity with process improvement techniques. Due to the limitations of the evidence, it is not known which approach, implementation of coordination measures or organisational restructuring (with additional coordination measures), produces the best results in which situation. Therefore, more research is needed. For this research, the use of qualitative methods in addition to quantitative measures is recommended to contribute to a better understanding of preconditions and contingencies for an effective application of approaches to become process-oriented. Hospitals are advised to take the factors for failure described into account and to take suitable actions to counteract these obstacles on their way to become process-oriented organisations.

The coil orientation dependency of the electric field induced by TMS for M1 and other brain areas.

PubMed

Janssen, Arno M; Oostendorp, Thom F; Stegeman, Dick F

2015-05-17

The effectiveness of transcranial magnetic stimulation (TMS) depends highly on the coil orientation relative to the subject's head. This implies that the direction of the induced electric field has a large effect on the efficiency of TMS. To improve future protocols, knowledge about the relationship between the coil orientation and the direction of the induced electric field on the one hand, and the head and brain anatomy on the other hand, seems crucial. Therefore, the induced electric field in the cortex as a function of the coil orientation has been examined in this study. The effect of changing the coil orientation on the induced electric field was evaluated for fourteen cortical targets. We used a finite element model to calculate the induced electric fields for thirty-six coil orientations (10 degrees resolution) per target location. The effects on the electric field due to coil rotation, in combination with target site anatomy, have been quantified. The results confirm that the electric field perpendicular to the anterior sulcal wall of the central sulcus is highly susceptible to coil orientation changes and has to be maximized for an optimal stimulation effect of the motor cortex. In order to obtain maximum stimulation effect in areas other than the motor cortex, the electric field perpendicular to the cortical surface in those areas has to be maximized as well. Small orientation changes (10 degrees) do not alter the induced electric field drastically. The results suggest that for all cortical targets, maximizing the strength of the electric field perpendicular to the targeted cortical surface area (and inward directed) optimizes the effect of TMS. Orienting the TMS coil based on anatomical information (anatomical magnetic resonance imaging data) about the targeted brain area can improve future results. The standard coil orientations, used in cognitive and clinical neuroscience, induce (near) optimal electric fields in the subject-specific head model in most cases.

Cross-orientation suppression in human visual cortex

PubMed Central

Heeger, David J.

2011-01-01

Cross-orientation suppression was measured in human primary visual cortex (V1) to test the normalization model. Subjects viewed vertical target gratings (of varying contrasts) with or without a superimposed horizontal mask grating (fixed contrast). We used functional magnetic resonance imaging (fMRI) to measure the activity in each of several hypothetical channels (corresponding to subpopulations of neurons) with different orientation tunings and fit these orientation-selective responses with the normalization model. For the V1 channel maximally tuned to the target orientation, responses increased with target contrast but were suppressed when the horizontal mask was added, evident as a shift in the contrast gain of this channel's responses. For the channel maximally tuned to the mask orientation, a constant baseline response was evoked for all target contrasts when the mask was absent; responses decreased with increasing target contrast when the mask was present. The normalization model provided a good fit to the contrast-response functions with and without the mask. In a control experiment, the target and mask presentations were temporally interleaved, and we found no shift in contrast gain, i.e., no evidence for suppression. We conclude that the normalization model can explain cross-orientation suppression in human visual cortex. The approach adopted here can be applied broadly to infer, simultaneously, the responses of several subpopulations of neurons in the human brain that span particular stimulus or feature spaces, and characterize their interactions. In addition, it allows us to investigate how stimuli are represented by the inferred activity of entire neural populations. PMID:21775720

Subtle perceptions of male sexual orientation influence occupational opportunities.

PubMed

Rule, Nicholas O; Bjornsdottir, R Thora; Tskhay, Konstantin O; Ambady, Nalini

2016-12-01

Theories linking the literatures on stereotyping and human resource management have proposed that individuals may enjoy greater success obtaining jobs congruent with stereotypes about their social categories or traits. Here, we explored such effects for a detectable, but not obvious, social group distinction: male sexual orientation. Bridging previous work on prejudice and occupational success with that on social perception, we found that perceivers rated gay and straight men as more suited to professions consistent with stereotypes about their groups (nurses, pediatricians, and English teachers vs. engineers, managers, surgeons, and math teachers) from mere photos of their faces. Notably, distinct evaluations of the gay and straight men emerged based on perceptions of their faces with no explicit indication of sexual orientation. Neither perceivers' expertise with hiring decisions nor diagnostic information about the targets eliminated these biases, but encouraging fair decisions did contribute to partly ameliorating the differences. Mediation analysis further showed that perceptions of the targets' sexual orientations and facial affect accounted for these effects. Individuals may therefore infer characteristics about individuals' group memberships from their faces and use this information in a way that meaningfully influences evaluations of their suitability for particular jobs. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Human factors analysis for a 2D enroute moving map application

NASA Astrophysics Data System (ADS)

Pschierer, Christian; Wipplinger, Patrick; Schiefele, Jens; Cromer, Scot; Laurin, John; Haffner, Skip

2005-05-01

The paper describes flight trials performed in Centennial, CO with a Piper Cheyenne from Marinvent. Six pilots flew the Cheyenne in twelve enroute segments between Denver Centennial and Colorado Springs. Two different settings (paper chart, enroute moving map) were evaluated with randomized settings. The flight trial goal was to evaluate the objective performance of pilots compared among the different settings. As dependent variables, positional accuracy and situational awareness probe (SAP) were measured. Analysis was conducted by an ANOVA test. In parallel, all pilots answered subjective Cooper-Harper, NASA TLX, situation awareness rating technique (SART), Display Readability Rating and debriefing questionnaires. The tested enroute moving map application has Jeppesen chart compliant symbologies for high-enroute and low-enroute. It has a briefing mode were all information found on today"s enroute paper chart together with a loaded flight plan are displayed in a north-up orientation. The execution mode displays a loaded flight plan routing together with only pertinent flight route relevant information in either a track up or north up orientation. Depiction of an own ship symbol is possible in both modes. All text and symbols are deconflicted. Additional information can be obtained by clicking on symbols. Terrain and obstacle data can be displayed for enhanced situation awareness. The result shows that pilots flying the 2D enroute moving map display perform no worse than pilots with conventional systems. Flight technical error and workload are equivalent or lower, situational awareness is higher than on conventional paper charts.

How Magnetic Disturbance Influences the Attitude and Heading in Magnetic and Inertial Sensor-Based Orientation Estimation.

PubMed

Fan, Bingfei; Li, Qingguo; Liu, Tao

2017-12-28

With the advancements in micro-electromechanical systems (MEMS) technologies, magnetic and inertial sensors are becoming more and more accurate, lightweight, smaller in size as well as low-cost, which in turn boosts their applications in human movement analysis. However, challenges still exist in the field of sensor orientation estimation, where magnetic disturbance represents one of the obstacles limiting their practical application. The objective of this paper is to systematically analyze exactly how magnetic disturbances affects the attitude and heading estimation for a magnetic and inertial sensor. First, we reviewed four major components dealing with magnetic disturbance, namely decoupling attitude estimation from magnetic reading, gyro bias estimation, adaptive strategies of compensating magnetic disturbance and sensor fusion algorithms. We review and analyze the features of existing methods of each component. Second, to understand each component in magnetic disturbance rejection, four representative sensor fusion methods were implemented, including gradient descent algorithms, improved explicit complementary filter, dual-linear Kalman filter and extended Kalman filter. Finally, a new standardized testing procedure has been developed to objectively assess the performance of each method against magnetic disturbance. Based upon the testing results, the strength and weakness of the existing sensor fusion methods were easily examined, and suggestions were presented for selecting a proper sensor fusion algorithm or developing new sensor fusion method.

Preclinical evaluation of injectable sirolimus formulated with polymeric nanoparticle for cancer therapy

PubMed Central

Woo, Ha Na; Chung, Hye Kyung; Ju, Eun Jin; Jung, Joohee; Kang, Hye-Won; Lee, Sa-Won; Seo, Min-Hyo; Lee, Jin Seong; Lee, Jung Shin; Park, Heon Joo; Song, Si Yeol; Jeong, Seong-Yun; Choi, Eun Kyung

2012-01-01

Nanoparticles are useful delivery vehicles for promising drug candidates that face obstacles for clinical applicability. Sirolimus, an inhibitor of mammalian target of rapamycin has gained attention for targeted anticancer therapy, but its clinical application has been limited by its poor solubility. This study was designed to enhance the feasibility of sirolimus for human cancer treatment. Polymeric nanoparticle (PNP)–sirolimus was developed as an injectable formulation and has been characterized by transmission electron microscopy and dynamic light scattering. Pharmacokinetic analysis revealed that PNP–sirolimus has prolonged circulation in the blood. In addition, PNP–sirolimus preserved the in vitro killing effect of free sirolimus against cancer cells, and intravenous administration displayed its potent in vivo anticancer efficacy in xenograft tumor mice. In addition, PNP–sirolimus enhanced the radiotherapeutic efficacy of sirolimus both in vitro and in vivo. Clinical application of PNP–sirolimus is a promising strategy for human cancer treatment. PMID:22619555

Single-Command Approach and Instrument Placement by a Robot on a Target

NASA Technical Reports Server (NTRS)

Huntsberger, Terrance; Cheng, Yang

2005-01-01

AUTOAPPROACH is a computer program that enables a mobile robot to approach a target autonomously, starting from a distance of as much as 10 m, in response to a single command. AUTOAPPROACH is used in conjunction with (1) software that analyzes images acquired by stereoscopic cameras aboard the robot and (2) navigation and path-planning software that utilizes odometer readings along with the output of the image-analysis software. Intended originally for application to an instrumented, wheeled robot (rover) in scientific exploration of Mars, AUTOAPPROACH could be adapted to terrestrial applications, notably including the robotic removal of land mines and other unexploded ordnance. A human operator generates the approach command by selecting the target in images acquired by the robot cameras. The approach path consists of multiple legs. Feature points are derived from images that contain the target and are thereafter tracked to correct odometric errors and iteratively refine estimates of the position and orientation of the robot relative to the target on successive legs. The approach is terminated when the robot attains the position and orientation required for placing a scientific instrument at the target. The workspace of the robot arm is then autonomously checked for self/terrain collisions prior to the deployment of the scientific instrument onto the target.

No apparent influence of psychometrically-defined schizotypy on orientation-dependent contextual modulation of visual contrast detection.

PubMed

Mannion, Damien J; Donkin, Chris; Whitford, Thomas J

2017-01-01

We investigated the relationship between psychometrically-defined schizotypy and the ability to detect a visual target pattern. Target detection is typically impaired by a surrounding pattern (context) with an orientation that is parallel to the target, relative to a surrounding pattern with an orientation that is orthogonal to the target (orientation-dependent contextual modulation). Based on reports that this effect is reduced in those with schizophrenia, we hypothesised that there would be a negative relationship between the relative score on psychometrically-defined schizotypy and the relative effect of orientation-dependent contextual modulation. We measured visual contrast detection thresholds and scores on the Oxford-Liverpool Inventory of Feelings and Experiences (O-LIFE) from a non-clinical sample ( N = 100). Contrary to our hypothesis, we find an absence of a monotonic relationship between the relative magnitude of orientation-dependent contextual modulation of visual contrast detection and the relative score on any of the subscales of the O-LIFE. The apparent difference of this result with previous reports on those with schizophrenia suggests that orientation-dependent contextual modulation may be an informative condition in which schizophrenia and psychometrically-defined schizotypy are dissociated. However, further research is also required to clarify the strength of orientation-dependent contextual modulation in those with schizophrenia.

Gyrokinetic simulation of driftwave instability in field-reversed configuration

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

Fulton, D. P., E-mail: dfulton@trialphaenergy.com; University of California, Irvine, California 92697; Lau, C. K.

2016-05-15

Following the recent remarkable progress in magnetohydrodynamic (MHD) stability control in the C-2U advanced beam driven field-reversed configuration (FRC), turbulent transport has become one of the foremost obstacles on the path towards an FRC-based fusion reactor. Significant effort has been made to expand kinetic simulation capabilities in FRC magnetic geometry. The recently upgraded Gyrokinetic Toroidal Code (GTC) now accommodates realistic magnetic geometry from the C-2U experiment at Tri Alpha Energy, Inc. and is optimized to efficiently handle the FRC's magnetic field line orientation. Initial electrostatic GTC simulations find that ion-scale instabilities are linearly stable in the FRC core for realisticmore » pressure gradient drives. Estimated instability thresholds from linear GTC simulations are qualitatively consistent with critical gradients determined from experimental Doppler backscattering fluctuation data, which also find ion scale modes to be depressed in the FRC core. Beyond GTC, A New Code (ANC) has been developed to accurately resolve the magnetic field separatrix and address the interaction between the core and scrape-off layer regions, which ultimately determines global plasma confinement in the FRC. The current status of ANC and future development targets are discussed.« less

Gyrokinetic simulation of driftwave instability in field-reversed configuration

NASA Astrophysics Data System (ADS)

Fulton, D. P.; Lau, C. K.; Schmitz, L.; Holod, I.; Lin, Z.; Tajima, T.; Binderbauer, M. W.

2016-05-01

Following the recent remarkable progress in magnetohydrodynamic (MHD) stability control in the C-2U advanced beam driven field-reversed configuration (FRC), turbulent transport has become one of the foremost obstacles on the path towards an FRC-based fusion reactor. Significant effort has been made to expand kinetic simulation capabilities in FRC magnetic geometry. The recently upgraded Gyrokinetic Toroidal Code (GTC) now accommodates realistic magnetic geometry from the C-2U experiment at Tri Alpha Energy, Inc. and is optimized to efficiently handle the FRC's magnetic field line orientation. Initial electrostatic GTC simulations find that ion-scale instabilities are linearly stable in the FRC core for realistic pressure gradient drives. Estimated instability thresholds from linear GTC simulations are qualitatively consistent with critical gradients determined from experimental Doppler backscattering fluctuation data, which also find ion scale modes to be depressed in the FRC core. Beyond GTC, A New Code (ANC) has been developed to accurately resolve the magnetic field separatrix and address the interaction between the core and scrape-off layer regions, which ultimately determines global plasma confinement in the FRC. The current status of ANC and future development targets are discussed.

77 FR 14587 - FY 2012 Discretionary Livability Funding Opportunity: Alternatives Analysis Program

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-12

... in clean energy resources, have been key strategic goals of the Department of Transportation (DOT... promote public health. Promote equitable, affordable housing: Expand location- and energy-efficient... communities: Target Federal funding toward existing communities--through such strategies as transit- oriented...

Endogenous orienting in the archer fish

PubMed Central

Sekely, Liora; Klein, Raymond M.; Gabay, Shai

2017-01-01

The literature has long emphasized the neocortex’s role in volitional processes. In this work, we examined endogenous orienting in an evolutionarily older species, the archer fish, which lacks neocortex-like cells. We used Posner’s classic endogenous cuing task, in which a centrally presented, spatially informative cue is followed by a target. The fish responded to the target by shooting a stream of water at it. Interestingly, the fish demonstrated a human-like “volitional” facilitation effect: their reaction times to targets that appeared on the side indicated by the precue were faster than their reaction times to targets on the opposite side. The fish also exhibited inhibition of return, an aftermath of orienting that commonly emerges only in reflexive orienting tasks in human participants. We believe that this pattern demonstrates the acquisition of an arbitrary connection between spatial orienting and a nonspatial feature of a centrally presented stimulus in nonprimate species. In the literature on human attention, orienting in response to such contingencies has been strongly associated with volitional control. We discuss the implications of these results for the evolution of orienting, and for the study of volitional processes in all species, including humans. PMID:28673997

Synthesis and Characterization of Molybdenum (Mo) Thin Films Using DC-Magnetron Sputtering

NASA Astrophysics Data System (ADS)

Pandharkar, Subhash M.; Rondiya, Sachin R.; Rokade, Avinash V.; Gabhale, Bharat B.; Pathan, Habib M.; Jadkar, Sandesh R.

2018-03-01

In present work, we report synthesis of Mo thin films by DC-magnetron sputtering method. The structural, optical, morphological and electrical properties were investigated as a function of target-to-substrate distance. From the results, it is evident that with increase in target-to-substrate distance the thickness of films decreases while its sheet resistance and electrical resistivity increases, which is confirmed by van der Pauw method. Low angle XRD analysis revealed that with increase in target-to-substrate distance preferred orientation of Mo crystallites changes from (211) to (110) and its size decreases. The FE-SEM analysis revealed a significant change in surface morphology with increase in target-to-substrate distance. UV-Visible spectroscopy analysis showed that Mo films deposited at high target-to-substrate distance have more reflection than those deposited at lower target-to-substrate. Finally, adhesion test was performed using scotch hatch tape adhesion test which show all Mo films have excellent adhesion over the entire range of target-to-substrate distance studied. The employment of such Mo films as back contact can be useful to improve efficiency of CZTS solar cells.

Reactive, Safe Navigation for Lunar and Planetary Robots

NASA Technical Reports Server (NTRS)

Utz, Hans; Ruland, Thomas

2008-01-01

When humans return to the moon, Astronauts will be accompanied by robotic helpers. Enabling robots to safely operate near astronauts on the lunar surface has the potential to significantly improve the efficiency of crew surface operations. Safely operating robots in close proximity to astronauts on the lunar surface requires reactive obstacle avoidance capabilities not available on existing planetary robots. In this paper we present work on safe, reactive navigation using a stereo based high-speed terrain analysis and obstacle avoidance system. Advances in the design of the algorithms allow it to run terrain analysis and obstacle avoidance algorithms at full frame rate (30Hz) on off the shelf hardware. The results of this analysis are fed into a fast, reactive path selection module, enforcing the safety of the chosen actions. The key components of the system are discussed and test results are presented.

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

Different protocols for analyzing behavior and adaptability in obstacle crossing in Parkinson's disease.

PubMed

Mollaei, Nafiseh; Bicho, Estela; Sousa, Nuno; Gago, Miguel Fernandes

2017-01-01

Imbalance and tripping over obstacles as a result of altered gait in older adults, especially in patients with Parkinson's disease (PD), are one of the most common causes of falls. During obstacle crossing, patients with PD modify their behavior in order to decrease the mechanical demands and enhance dynamic stability. Various descriptions of dynamic traits of gait that have been collected over longer periods, probably better synthesize the underlying structure and pattern of fluctuations in gait and can be more sensitive markers of aging or early neurological dysfunction and increased risk of falls. This confirmation challenges the clinimetric of different protocols and paradigms used for gait analysis up till now, in particular when analyzing obstacle crossing. The authors here present a critical review of current knowledge concerning the interplay between the cognition and gait in aging and PD, emphasizing the differences in gait behavior and adaptability while walking over different and challenging obstacle paradigms, and the implications of obstacle negotiation as a predictor of falls. Some evidence concerning the effectiveness of future rehabilitation protocols on reviving obstacle crossing behavior by trial and error relearning, taking advantage of dual-task paradigms, physical exercise, and virtual reality have been put forward in this article.

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

Perceived Sexual Orientation of Men and Women with Eating Disorders and Obesity.

PubMed

Essayli, Jamal H; Murakami, Jessica M; Latner, Janet D

2018-06-04

The present study explores the perceived sexual orientation of hypothetical men and women with various eating disorders and obesity. Undergraduates were randomly provided with one vignette describing a male or female with anorexia nervosa (AN), bulimia nervosa (BN), binge-eating disorder, or obesity and were asked about the target's likely sexual orientation. Significant differences emerged between male and female targets with AN and BN on the forced-choice question, with a greater percentage of participants indicating that the male targets were probably non-heterosexual. On continuous items, participants rated the female targets as significantly more likely to be heterosexual and significantly less likely to be homosexual than male targets. The general public may be more likely to perceive men with eating disorders as gay or bisexual relative to females with eating disorders. Perceived sexual orientation might be an important factor to consider when exploring the potentially unique perspectives of men with eating disorders.

Mesoscale Thermodynamic Analysis of Atomic-Scale Dislocation-Obstacle Interactions Simulated by Molecular Dynamics

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

Monet, Giath; Bacon, David J; Osetskiy, Yury N

2010-01-01

Given the time and length scales in molecular dynamics (MD) simulations of dislocation-defect interactions, quantitative MD results cannot be used directly in larger scale simulations or compared directly with experiment. A method to extract fundamental quantities from MD simulations is proposed here. The first quantity is a critical stress defined to characterise the obstacle resistance. This mesoscopic parameter, rather than the obstacle 'strength' designed for a point obstacle, is to be used for an obstacle of finite size. At finite temperature, our analyses of MD simulations allow the activation energy to be determined as a function of temperature. The resultsmore » confirm the proportionality between activation energy and temperature that is frequently observed by experiment. By coupling the data for the activation energy and the critical stress as functions of temperature, we show how the activation energy can be deduced at a given value of the critical stress.« less

Intercellular Communication by Exosome-Derived microRNAs in Cancer

PubMed Central

Hannafon, Bethany N.; Ding, Wei-Qun

2013-01-01

The development of human cancers is a multistep process in which normal cells acquire characteristics that ultimately lead to their conversion into cancer cells. Many obstacles must be overcome for this process to occur; of these obstacles, is the ability to survive an inhospitable microenvironment. It is recognized that the intercommunication between tumor cells and their surrounding microenvironment is essential to overcoming this obstacle and for the tumor to progress, metastasize and establish itself at distant sites. Exosomes are membrane-derived vesicles that have recently been recognized as important mediators of intercellular communication, as they carry lipids, proteins, mRNAs and microRNAs that can be transferred to a recipient cell via fusion of the exosome with the target cell membrane. In the context of cancer cells, this process entails the transfer of cancer-promoting cellular contents to surrounding cells within the tumor microenvironment or into the circulation to act at distant sites, thereby enabling cancer progression. In this process, the transfer of exosomal microRNAs to a recipient cell where they can regulate target gene expression is of particular interest, both in understanding the basic biology of cancer progression and for the development of therapeutic approaches. This review discusses the exosome-mediated intercellular communication via microRNAs within the tumor microenvironment in human cancers, with a particular focus on breast cancer exosomes. PMID:23839094

Perceived Sexual Orientation Based on Vocal and Facial Stimuli Is Linked to Self-Rated Sexual Orientation in Czech Men

PubMed Central

Valentova, Jaroslava Varella; Havlíček, Jan

2013-01-01

Previous research has shown that lay people can accurately assess male sexual orientation based on limited information, such as face, voice, or behavioral display. Gender-atypical traits are thought to serve as cues to sexual orientation. We investigated the presumed mechanisms of sexual orientation attribution using a standardized set of facial and vocal stimuli of Czech men. Both types of stimuli were rated for sexual orientation and masculinity-femininity by non-student heterosexual women and homosexual men. Our data showed that by evaluating vocal stimuli both women and homosexual men can judge sexual orientation of the target men in agreement with their self-reported sexual orientation. Nevertheless, only homosexual men accurately attributed sexual orientation of the two groups from facial images. Interestingly, facial images of homosexual targets were rated as more masculine than heterosexual targets. This indicates that attributions of sexual orientation are affected by stereotyped association between femininity and male homosexuality; however, reliance on such cues can lead to frequent misjudgments as was the case with the female raters. Although our study is based on a community sample recruited in a non-English speaking country, the results are generally consistent with the previous research and thus corroborate the validity of sexual orientation attributions. PMID:24358180

An ethnographic study for understanding children's oral health in a multicultural community.

PubMed

Riedy, C A; Weinstein, P; Milgrom, P; Bruss, M

2001-08-01

To provide guidance for a public health intervention in a high caries rate multicultural population by understanding cultural issues surrounding children's oral health. Seven community focus groups were conducted with five ethnic populations (Chamorro, Filipino, Carolinian, Pohnpean, and Chuukese) living on the island of Saipan, Commonwealth of the Northern Mariana Islands, USA. Participants were asked questions about their beliefs, attitudes, knowledge, and care practices regarding issues around children's oral health. Analysis consisted of a content review of participants' responses within two targeted areas: past and current attitudes and health beliefs, and behaviours impacting risk of developing disease. Both the lack of value of baby teeth and negative parental experiences are factors underlying health beliefs and behaviours. Although some differences in beliefs and practices existed across cultural groups, most women were interested in learning about new preventive strategies to reduce dental disease. Several new mothers reported that they actively sought out parenting information during their initial pregnancy. Aversive parental experience and disregard for primary dentition were identified as serious obstacles to be addressed in order for any new programme to be effective. Despite these obstacles, new mothers were open to information and strategies to reduce the prevalence of early childhood caries.

Mechanistic Insights into Archaeal and Human Argonaute Substrate Binding and Cleavage Properties

PubMed Central

Willkomm, Sarah; Zander, Adrian; Grohmann, Dina; Restle, Tobias

2016-01-01

Argonaute (Ago) proteins from all three domains of life are key players in processes that specifically regulate cellular nucleic acid levels. Some of these Ago proteins, among them human Argonaute2 (hAgo2) and Ago from the archaeal organism Methanocaldococcus jannaschii (MjAgo), are able to cleave nucleic acid target strands that are recognised via an Ago-associated complementary guide strand. Here we present an in-depth kinetic side-by-side analysis of hAgo2 and MjAgo guide and target substrate binding as well as target strand cleavage, which enabled us to disclose similarities and differences in the mechanistic pathways as a function of the chemical nature of the substrate. Testing all possible guide-target combinations (i.e. RNA/RNA, RNA/DNA, DNA/RNA and DNA/DNA) with both Ago variants we demonstrate that the molecular mechanism of substrate association is highly conserved among archaeal-eukaryotic Argonautes. Furthermore, we show that hAgo2 binds RNA and DNA guide strands in the same fashion. On the other hand, despite striking homology between the two Ago variants, MjAgo cannot orientate guide RNA substrates in a way that allows interaction with the target DNA in a cleavage-compatible orientation. PMID:27741323

SANE's Measurement of the Proton's Virtual Photon Spin Asymmetry, A p 1, at Large Bjorken x

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

Mulholland, Jonathan

2012-05-01

The experiment SANE (Spin Asymmetries of the Nucleon Experiment) measured inclusive double polarization electron asymmetries on a proton target at the Continuous Electron Beam Accelerator Facility at the Thomas Jefferson National Laboratory in Newport News Virgina. Polarized electrons were scattered from a solid 14NH 3 polarized target provided by the University of Virginia target group. Measurements were taken with the target polarization oriented at 80 degrees and 180 degrees relative to the beam direction, and beam energies of 4.7 and 5.9 GeV were used. Scattered electrons were detected by a multi-component novel non-magnetic detector package constructed for this experiment. Asymmetriesmore » measured at the two target orientations allow for the extraction of the virtual Compton asymmetries A 1 p and A 2 p as well as the spin structure functions g 1 p and g 2 p. This work addresses the extraction of the virtual Compton asymmetry A 1 p in the deep inelastic regime. The analysis uses data in the kinematic range from Bjorken x of 0.30 to 0.55, separated into four Q 2 bins from 1.9 to 4.7 GeV 2.« less

Modeling fluid diffusion in cerebral white matter with random walks in complex environments

NASA Astrophysics Data System (ADS)

Levy, Amichai; Cwilich, Gabriel; Buldyrev, Sergey V.; Weeden, Van J.

2012-02-01

Recent studies with diffusion MRI have shown new aspects of geometric order in the brain, including complex path coherence within the cerebral cortex, and organization of cerebral white matter and connectivity across multiple scales. The main assumption of these studies is that water molecules diffuse along myelin sheaths of neuron axons in the white matter and thus the anisotropy of their diffusion tensor observed by MRI can provide information about the direction of the axons connecting different parts of the brain. We model the diffusion of particles confined in the space of between the bundles of cylindrical obstacles representing fibrous structures of various orientations. We have investigated the directional properties of the diffusion, by studying the angular distribution of the end point of the random walks as a function of their length, to understand the scale over which the distribution randomizes. We will show evidence of qualitative change in the behavior of the diffusion for different volume fractions of obstacles. Comparisons with three-dimensional MRI images will be illustrated.

Establishing the behavioural limits for countershaded camouflage.

PubMed

Penacchio, Olivier; Harris, Julie M; Lovell, P George

2017-10-20

Countershading is a ubiquitous patterning of animals whereby the side that typically faces the highest illumination is darker. When tuned to specific lighting conditions and body orientation with respect to the light field, countershading minimizes the gradient of light the body reflects by counterbalancing shadowing due to illumination, and has therefore classically been thought of as an adaptation for visual camouflage. However, whether and how crypsis degrades when body orientation with respect to the light field is non-optimal has never been studied. We tested the behavioural limits on body orientation for countershading to deliver effective visual camouflage. We asked human participants to detect a countershaded target in a simulated three-dimensional environment. The target was optimally coloured for crypsis in a reference orientation and was displayed at different orientations. Search performance dramatically improved for deviations beyond 15 degrees. Detection time was significantly shorter and accuracy significantly higher than when the target orientation matched the countershading pattern. This work demonstrates the importance of maintaining body orientation appropriate for the displayed camouflage pattern, suggesting a possible selective pressure for animals to orient themselves appropriately to enhance crypsis.

Walking-adaptability assessments with the Interactive Walkway: Between-systems agreement and sensitivity to task and subject variations.

PubMed

Geerse, Daphne J; Coolen, Bert H; Roerdink, Melvyn

2017-05-01

The ability to adapt walking to environmental circumstances is an important aspect of walking, yet difficult to assess. The Interactive Walkway was developed to assess walking adaptability by augmenting a multi-Kinect-v2 10-m walkway with gait-dependent visual context (stepping targets, obstacles) using real-time processed markerless full-body kinematics. In this study we determined Interactive Walkway's usability for walking-adaptability assessments in terms of between-systems agreement and sensitivity to task and subject variations. Under varying task constraints, 21 healthy subjects performed obstacle-avoidance, sudden-stops-and-starts and goal-directed-stepping tasks. Various continuous walking-adaptability outcome measures were concurrently determined with the Interactive Walkway and a gold-standard motion-registration system: available response time, obstacle-avoidance and sudden-stop margins, step length, stepping accuracy and walking speed. The same holds for dichotomous classifications of success and failure for obstacle-avoidance and sudden-stops tasks and performed short-stride versus long-stride obstacle-avoidance strategies. Continuous walking-adaptability outcome measures generally agreed well between systems (high intraclass correlation coefficients for absolute agreement, low biases and narrow limits of agreement) and were highly sensitive to task and subject variations. Success and failure ratings varied with available response times and obstacle types and agreed between systems for 85-96% of the trials while obstacle-avoidance strategies were always classified correctly. We conclude that Interactive Walkway walking-adaptability outcome measures are reliable and sensitive to task and subject variations, even in high-functioning subjects. We therefore deem Interactive Walkway walking-adaptability assessments usable for obtaining an objective and more task-specific examination of one's ability to walk, which may be feasible for both high-functioning and fragile populations since walking adaptability can be assessed at various levels of difficulty. Copyright © 2017 Elsevier B.V. All rights reserved.

Two dimensional numerical analysis of snow avalanche interaction with structures

NASA Astrophysics Data System (ADS)

Bovet, Eloïse; Chiaia, Bernardino; Preziosi, Luigi

2010-05-01

The purpose of this work, within the Project "DynAval - Dynamique des avalanches: départ et interactions écoulement/obstacles" - European Territorial Cooperation objective Italy - France (Alps), is to analyse the snow avalanche and structure interaction, through a numerical analysis. The avalanche behaviour, considered as an incompressible fluid, is described by a two-dimensional, in the avalanche slope, Navier-Stokes equations to which an advection equation is coupled to take into account the shape variation. The model allows to describe the velocity and the pressure at every point, representing important features for the structural design. The simulations are carried using a FEM Multiphysics software. For a such problem different analysis can be carried. Firstly, changing the obstacle shape (circle, square, triangle) and its dimension in relation to the avalanche size, the drag coefficient Cd can be evaluated. The obtained results are then compared with the values indicated by the procedures, concerning the avalanches, available in the literature. This study is realized for different Froude numbers too. Secondarily the pressure acting on the different parts of the obstacle (up-wind, down-wind, lateral) is studied. The first investigation concerns the evaluation of the Cp coefficient and on its comparison with the wind effects. The second analysis allows to evaluates, by an integration process, the total load exerted by the avalanche on the obstacle. A practical example of a building design is presented, taking into account the results of the simulations. Thirdly the study is focused on the characterization of the two dead zones created up-wind and down-wind the obstacle. The dependence of the dead zone on the obstacle characteristics, such as dimension and shape, and on the avalanche features, such as density and velocity, is analysed. The results obtained are compared with the data available in the literature concerning snow or granular material interaction with obstacle. In addition the dead zone is studied using a two dimensional model in the avalanche section too. In this way, in fact, the jet length created in the impact, for instance with a dam, can be measured and compared with the laws proposed in the literature. Fourthly the evolution in time of the pressure during the impact is investigated, showing a peak in the first times steps of the interaction. The time and the intensity of this maximum value is related with the flow and the obstacle characteristics. In conclusion, the fan of the analysis carried recovers different and very important features that represent the starting point for reliable design of the structures in avalanche-risk zones. In addition it shows the capabilities and the deficiencies of the model proposed and, finally, it introduces some aspects that will should be furtherer experimentally studied and validated.

The analysis of the market success of FDA approvals by probing top 100 bestselling drugs.

PubMed

Polanski, Jaroslaw; Bogocz, Jacek; Tkocz, Aleksandra

2016-05-01

Target-oriented drug discovery is the main research paradigm of contemporary drug discovery. In target-oriented approaches, we attempt to maximize in vitro drug potency by finding the optimal fit to the target. This can result in a higher molecular complexity, in particular, the higher molecular weight (MW) of the drugs. However, a comparison of the successful developments of pharmaceuticals with the general trends that can be observed in medicinal chemistry resulted in the conclusion that the so-called molecular obesity is an important reason for the attrition rate of drugs. When analyzing the list of top 100 drug bestsellers versus all of the FDA approvals, we discovered that on average lower-complexity (MW, ADMET score) drugs are winners of the top 100 list in terms of numbers but that, especially, up to some optimal MW value, a higher molecular complexity can pay off with higher incomes. This indicates that slim drugs are doing better but that fat drugs are bigger fishes to catch.

The analysis of the market success of FDA approvals by probing top 100 bestselling drugs

NASA Astrophysics Data System (ADS)

Polanski, Jaroslaw; Bogocz, Jacek; Tkocz, Aleksandra

2016-05-01

Target-oriented drug discovery is the main research paradigm of contemporary drug discovery. In target-oriented approaches, we attempt to maximize in vitro drug potency by finding the optimal fit to the target. This can result in a higher molecular complexity, in particular, the higher molecular weight (MW) of the drugs. However, a comparison of the successful developments of pharmaceuticals with the general trends that can be observed in medicinal chemistry resulted in the conclusion that the so-called molecular obesity is an important reason for the attrition rate of drugs. When analyzing the list of top 100 drug bestsellers versus all of the FDA approvals, we discovered that on average lower-complexity (MW, ADMET score) drugs are winners of the top 100 list in terms of numbers but that, especially, up to some optimal MW value, a higher molecular complexity can pay off with higher incomes. This indicates that slim drugs are doing better but that fat drugs are bigger fishes to catch.

Featural Guidance in Conjunction Search: The Contrast between Orientation and Color

ERIC Educational Resources Information Center

Anderson, Giles M.; Heinke, Dietmar; Humphreys, Glyn W.

2010-01-01

Four experiments examined the effects of precues on visual search for targets defined by a color-orientation conjunction. Experiment 1 showed that cueing the identity of targets enhanced the efficiency of search. Cueing effects were stronger with color than with orientation cues, but this advantage was additive across array size. Experiment 2…

A cross-media content analysis of motivational themes in direct-to-consumer prescription drug advertising.

PubMed

Sumpradit, Nithima; Ascione, Frank J; Bagozzi, Richard P

2004-01-01

Direct-to-consumer (DTC) advertising of prescription drugs is a widely discussed issue in health care. However, little is known about the characteristics of the motivational themes used in this type of advertising. The aim of this study was to investigate the concurrent presentation of motivational themes in DTC print and television advertisements. The content analyses focused on advertisements of 2 targeted drug classes (cyclooxygenase-2 enzyme inhibitors and 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors) in magazines and on television. Targeted print advertisements (for celecoxib, rofecoxib, atorvastatin, pravastatin, and simvastatin) from September to December 2001 and targeted television advertisements (for celecoxib, rofecoxib, and simvastatin) from November 2001 were investigated. The motivational themes were assessed using a theoretical framework based on self-regulatory focus theory and cultural orientation. Self-regulatory focus was examined in terms of goal orientation (promotion vs prevention) and emotional aspects, (e.g., cheerfulness, dejection, quiescence, agitation). The cultural orientation was examined in terms of individualism versus collectivism. The visual-verbal match was categorized as direct if the audio and visual information was semantically redundant, as partial if it was partially related, and as no match at all if it was different or conflicting. Twelve print advertisements in 10 magazines and 4 television advertisements on 4 television networks were examined; the interrater reliability scores from 3 independent, trained judges ranged from 0.93 to 0.99. The score was low (0.57) in the visual-verbal match measurement for television advertisements. Products in the same category appeared to be promoted using different self-regulatory foci. For example, celecoxib and atorvastatin advertisements tended to be promotion oriented, whereas pravastatin advertisements tended to be prevention oriented. Motivational themes were found throughout the print advertisements (e.g., pictures, headlines, main text). Only a few advertisements illustrated factual information about a product in a pictorial format. The cultural orientation of the advertisements was similar across brands, with individualistic appeals being common. On television, visual-verbal matches (either direct or partial matches) were generally found, except in the section where risk information was presented. In this content analysis, prescription drugs in the same class appeared to be promoted using different self-regulatory foci, but individualistic appeals were found more often than collectivistic appeals across brands.

Electrophysiological correlates of stimulus-driven reorienting deficits after interference with right parietal cortex during a spatial attention task: a TMS-EEG study

PubMed Central

Capotosto, Paolo; Corbetta, Maurizio; Romani, Gian Luca; Babiloni, Claudio

2013-01-01

Transcranial magnetic stimulation (TMS) interference over right intraparietal sulcus (IPS) causally disrupts behaviorally and electroencephalographic (EEG) rhythmic correlates of endogenous spatial orienting prior to visual target presentation (Capotosto et al. 2009; 2011). Here we combine data from our previous studies to examine whether right parietal TMS during spatial orienting also impairs stimulus-driven re-orienting or the ability to efficiently process unattended stimuli, i.e. stimuli outside the current focus of attention. Healthy subjects (N=24) performed a Posner spatial cueing task while their EEG activity was being monitored. Repetitive TMS (rTMS) was applied for 150 milliseconds (ms) simultaneously to the presentation of a central arrow directing spatial attention to the location of an upcoming visual target. Right IPS-rTMS impaired target detection, especially for stimuli presented at unattended locations; it also caused a modulation of the amplitude of parieto-occipital positive ERPs peaking at about 480 ms (P3) post-target. The P3 significantly decreased for unattended targets, and significantly increased for attended targets after right IPS-rTMS as compared to Sham stimulation. Similar effects were obtained for left IPS stimulation albeit in a smaller group of subjects. We conclude that disruption of anticipatory processes in right IPS has prolonged effects that persist during target processing. The P3 decrement may reflect interference with post-decision processes that are part of stimulus-driven re-orienting. Right IPS is a node of functional interaction between endogenous spatial orienting and stimulus-driven re-orienting processes in human vision. PMID:22905824

Vision-Based UAV Flight Control and Obstacle Avoidance

DTIC Science & Technology

2006-01-01

denoted it by Vb = (Vb1, Vb2 , Vb3). Fig. 2 shows the block diagram of the proposed vision-based motion analysis and obstacle avoidance system. We denote...structure analysis often involve computation- intensive computer vision tasks, such as feature extraction and geometric modeling. Computation-intensive...First, we extract a set of features from each block. 2) Second, we compute the distance between these two sets of features. In conventional motion

Mobility performance analysis of an innovation lunar rover with diameter-variable wheel

NASA Astrophysics Data System (ADS)

Sun, Gang; Gao, Feng; Sun, Peng; Xu, Guoyan

2007-11-01

To achieve excellent mobility performance, a four-wheel, all-wheel drive lunar rover with diameter-variable wheel was presented, the wheel can be contracted and extended by the motor equipped in the wheel hub, accompanied with wheel diameter varying from 200mm to 390mm. The wheel sinkage and drawbar pull force were predicated with terramechanics formulae and lunar regolith mechanic parameters employed, furthermore, the slope traversability was investigated through quasi-static modeling mechanic analysis, also the obstacle resistance and the maximum negotiable obstacle height for different wheel radius were derived from the equations of static equilibrium of the rover. Analysis results show that for the innovation lunar rover presented, it will bring much better slope traveling stability and obstacle climbing capability than rovers with normal wheels, these will improve the rover mobility performance and stabilize the rover's frame, smooth the motion of sensors.

Identifying Contingency Requirements using Obstacle Analysis on an Unpiloted Aerial Vehicle

NASA Technical Reports Server (NTRS)

Lutz, Robyn R.; Nelson, Stacy; Patterson-Hine, Ann; Frost, Chad R.; Tal, Doron

2005-01-01

This paper describes experience using Obstacle Analysis to identify contingency requirements on an unpiloted aerial vehicle. A contingency is an operational anomaly, and may or may not involve component failure. The challenges to this effort were: ( I ) rapid evolution of the system while operational, (2) incremental autonomy as capabilities were transferred from ground control to software control and (3) the eventual safety-criticality of such systems as they begin to fly over populated areas. The results reported here are preliminary but show that Obstacle Analysis helped (1) identify new contingencies that appeared as autonomy increased; (2) identify new alternatives for handling both previously known and new contingencies; and (3) investigate the continued validity of existing software requirements for contingency handling. Since many mobile, intelligent systems are built using a development process that poses the same challenges, the results appear to have applicability to other similar systems.

Epistemological Obstacles on the Topic of Ratio and Proportion among Junior High School Students

NASA Astrophysics Data System (ADS)

Wahyuningrum, A. S.; Suryadi, D.; Turmudi

2017-09-01

This study intends to investigate how students’ understanding of ratio and proportion concept indicates epistemological obstacles. It was part of Didactical Design Research which was conducted to 72 students of 8th grade who ever learned about ratio and proportion. Data were collected through the students’ answers and interview in solving ratio and proportion problems. The results show that students’ conception, the ways of applying other mathematical concepts, the ways of using the rules, and variety of contexts are factors influencing epistemological obstacles in teaching and learning of ratio and proportion. These conditions can affect the students’ understanding o f related mathematics topics. Based on analysis of the results, this study is expected to overcome or minimize the epistemological obstacles.

Recognition of three dimensional obstacles by an edge detection scheme. [for Mars roving vehicle using laser range finder

NASA Technical Reports Server (NTRS)

Reed, M. A.

1974-01-01

The need for an obstacle detection system on the Mars roving vehicle was assumed, and a practical scheme was investigated and simulated. The principal sensing device on this vehicle was taken to be a laser range finder. Both existing and original algorithms, ending with thresholding operations, were used to obtain the outlines of obstacles from the raw data of this laser scan. A theoretical analysis was carried out to show how proper value of threshold may be chosen. Computer simulations considered various mid-range boulders, for which the scheme was quite successful. The extension to other types of obstacles, such as craters, was considered. The special problems of bottom edge detection and scanning procedure are discussed.

Contextual influence on orientation discrimination of humans and responses of neurons in V1 of alert monkeys.

PubMed

Li, W; Thier, P; Wehrhahn, C

2000-02-01

We studied the effects of various patterns as contextual stimuli on human orientation discrimination, and on responses of neurons in V1 of alert monkeys. When a target line is presented along with various contextual stimuli (masks), human orientation discrimination is impaired. For most V1 neurons, responses elicited by a line in the receptive field (RF) center are suppressed by these contextual patterns. Orientation discrimination thresholds of human observers are elevated slightly when the target line is surrounded by orthogonal lines. For randomly oriented lines, thresholds are elevated further and even more so for lines parallel to the target. Correspondingly, responses of most V1 neurons to a line are suppressed. Although contextual lines inhibit the amplitude of orientation tuning functions of most V1 neurons, they do not systematically alter the tuning width. Elevation of human orientation discrimination thresholds decreases with increasing curvature of masking lines, so does the inhibition of V1 neuronal responses. A mask made of straight lines yields the strongest interference with human orientation discrimination and produces the strongest suppression of neuronal responses. Elevation of human orientation discrimination thresholds is highest when a mask covers only the immediate vicinity of the target line. Increasing the masking area results in less interference. On the contrary, suppression of neuronal responses in V1 increases with increasing mask size. Our data imply that contextual interference observed in human orientation discrimination is in part directly related to contextual inhibition of neuronal activity in V1. However, the finding that interference with orientation discrimination is weaker for larger masks suggests a figure-ground segregation process that is not located in V1.

Targeted microbubbles with ultrasound irradiation and PD-1 inhibitor to increase antitumor activity in B-cell lymphoma.

PubMed

Zheng, Shiya; Song, Dan; Jin, Xiaoxiao; Zhang, Haijun; Aldarouish, Mohanad; Chen, Yan; Wang, Cailian

2018-02-01

Severe cardiac toxicity of doxorubicin and an immunosuppressive tumor micro-environment become main obstacles for the effective treatment of B-cell lymphoma. In this research, rituximab-conjugated and doxorubicin-loaded microbubbles (RDMs) were designed for exploring a combination approach of targeted microbubbles with ultrasound (US) irradiation and PD-1 inhibitor to overcome obstacles mentioned above. In vivo studies were performed on SU-DHL-4 cell-grafted mice and ex vivo studies were performed on CD20 + human SU-DHL-4 cells and human T cells. A greater therapeutic effect and higher expression of PD-L1 protein expression were obtained with RDMs with US irradiation in vivo. A significant inhibitory effect on SU-DHL-4 B-cell lymphoma cells was observed after treated by RDMs with US irradiation and PD-1 inhibitor ex vivo. Combination of RDMs with US irradiation and PD-1 inhibitor could be a promising therapeutic strategy for B-cell lymphoma.

Handedness helps homing in swimming and flying animals

PubMed Central

Bandyopadhyay, Promode R.; Leinhos, Henry A.; Hellum, Aren M.

2013-01-01

Swimming and flying animals rely on their ability to home on mobile targets. In some fish, physiological handedness and homing correlate, and dolphins exhibit handedness in their listening response. Here, we explore theoretically whether the actuators, sensors, and controllers in these animals follow similar laws of self-regulation, and how handedness affects homing. We find that the acoustic sensor (combined hydrophone-accelerometer) response maps are similar to fin force maps—modeled by Stuart-Landau oscillators—allowing localization by transitional vortex-propelled animals. The planar trajectories of bats in a room filled with obstacles are approximately reproduced by the states of a pair of strong and weak olivo-cerebellar oscillators. The stereoscopy of handedness reduces ambiguity near a mobile target, resulting in accelerated homing compared to even-handedness. Our results demonstrate how vortex-propelled animals may be localizing each other and circumventing obstacles in changing environments. Handedness could be useful in time-critical robot-assisted rescues in hazardous environments. PMID:23350035

Optimal Navigation of Self-Propelled Colloids in Microstructured Mazes

NASA Astrophysics Data System (ADS)

Yang, Yuguang; Bevan, Michael

Controlling navigation of self-propelled microscopic `robots' subject to random Brownian motion in complex microstructured environments (e.g., porous media, tumor vasculature) is important to many emerging applications (e.g., enhanced oil recovery, drug delivery). In this work, we design an optimal feedback policy to navigate an active self-propelled colloidal rod in complex mazes with various obstacle types. Actuation of the rods is modelled based on a light-controlled osmotic flow mechanism, which produces different propulsion velocities along the rod's long axis. Actuator-parameterized Langevin equations, with soft rod-obstacle repulsive interactions, are developed to describe the system dynamics. A Markov decision process (MDP) framework is used for optimal policy calculations with design goals of colloidal rods reaching target end points in minimum time. Simulations show that optimal MDP-based policies are able to control rod trajectories to reach target regions order-of-magnitudes faster than uncontrolled rods, which diverges as maze complexity increases. An efficient multi-graph based implementation for MDP is also presented, which scales linearly with the maze dimension.

Open angle glaucoma effects on preattentive visual search efficiency for flicker, motion displacement and orientation pop-out tasks.

PubMed

Loughman, James; Davison, Peter; Flitcroft, Ian

2007-11-01

Preattentive visual search (PAVS) describes rapid and efficient retinal and neural processing capable of immediate target detection in the visual field. Damage to the nerve fibre layer or visual pathway might reduce the efficiency with which the visual system performs such analysis. The purpose of this study was to test the hypothesis that patients with glaucoma are impaired on parallel search tasks, and that this would serve to distinguish glaucoma in early cases. Three groups of observers (glaucoma patients, suspect and normal individuals) were examined, using computer-generated flicker, orientation, and vertical motion displacement targets to assess PAVS efficiency. The task required rapid and accurate localisation of a singularity embedded in a field of 119 homogeneous distractors on either the left or right-hand side of a computer monitor. All subjects also completed a choice reaction time (CRT) task. Independent sample T tests revealed PAVS efficiency to be significantly impaired in the glaucoma group compared with both normal and suspect individuals. Performance was impaired in all types of glaucoma tested. Analysis between normal and suspect individuals revealed a significant difference only for motion displacement response times. Similar analysis using a PAVS/CRT index confirmed the glaucoma findings but also showed statistically significant differences between suspect and normal individuals across all target types. A test of PAVS efficiency appears capable of differentiating early glaucoma from both normal and suspect cases. Analysis incorporating a PAVS/CRT index enhances the diagnostic capacity to differentiate normal from suspect cases.

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

Automated path planning of the Payload Inspection and Processing System

NASA Technical Reports Server (NTRS)

Byers, Robert M.

1994-01-01

The Payload Changeout Room Inspection and Processing System (PIPS) is a highly redundant manipulator intended for performing tasks in the crowded and sensitive environment of the Space Shuttle Orbiter payload bay. Its dexterity will be exploited to maneuver the end effector in a workspace populated with obstacles. A method is described by which the end effector of a highly redundant manipulator is directed toward a target via a Lyapunov stability function. A cost function is constructed which represents the distance from the manipulator links to obstacles. Obstacles are avoided by causing the vector of joint parameters to move orthogonally to the gradient of the workspace cost function. A C language program implements the algorithm to generate a joint history. The resulting motion is graphically displayed using the Interactive Graphical Robot Instruction Program (IGRIP) produced by Deneb Robotics. The graphical simulation has the potential to be a useful tool in path planning for the PIPS in the Shuttle Payload Bay environment.

Measuring attention using the Posner cuing paradigm: the role of across and within trial target probabilities

PubMed Central

Hayward, Dana A.; Ristic, Jelena

2013-01-01

Numerous studies conducted within the recent decades have utilized the Posner cuing paradigm for eliciting, measuring, and theoretically characterizing attentional orienting. However, the data from recent studies suggest that the Posner cuing task might not provide an unambiguous measure of attention, as reflexive spatial orienting has been found to interact with extraneous processes engaged by the task's typical structure, i.e., the probability of target presence across trials, which affects tonic alertness, and the probability of target presence within trials, which affects voluntary temporal preparation. To understand the contribution of each of these two processes to the measurement of attentional orienting we assessed their individual and combined effects on reflexive attention elicited by a spatially nonpredictive peripheral cue. Our results revealed that the magnitude of spatial orienting was modulated by joint changes in the global probability of target presence across trials and the local probability of target presence within trials, while the time course of spatial orienting was susceptible to changes in the probability of target presence across trials. These data thus raise important questions about the choice of task parameters within the Posner cuing paradigm and their role in both the measurement and theoretical attributions of the observed attentional effects. PMID:23730280

Why TQM does not work in Iranian healthcare organisations.

PubMed

Mosadeghrad, Ali Mohammad

2014-01-01

Despite the potential benefits of total quality management (TQM), many healthcare organisations encountered difficulties in its implementation. The purpose of this paper is to explore the barriers to successful implementation of TQM in healthcare organisations of Iran. This study involved a mixed research design. In-depth interviews were conducted with TQM practitioners to explore TQM implementation obstacles in Iranian healthcare organisations. In addition, this study involved survey-based research on the obstacles associated with successful TQM transformation. TQM implementation and its impact depend on the ability of managers to adopt and adapt its values and concepts in professional healthcare organisations. Unsuccessful TQM efforts in Iranian healthcare organisations can be attributed to the non-holistic approach adopted in its implementation, inadequate knowledge of managers' about TQM implementation, frequent top management turnover, poor planning, vague and short-termed improvement goals, lack of consistent managers' and employees' commitment to and involvement in TQM implementation, lack of a corporate quality culture, lack of team orientation, lack of continuous education and training and lack of customer focus. Human resource problems, cultural and strategic problems were the most important obstacles to TQM successful implementation, respectively. Understanding the factors that are likely to obstruct TQM implementation would enable managers to develop more viable strategies for achieving business excellence. Understanding the factors that are likely to obstruct TQM implementation will help organisations in planning better TQM models.

Waist-up protection for blind individuals using the EyeCane as a primary and secondary mobility aid

PubMed Central

Buchs, Galit; Simon, Noa; Maidenbaum, Shachar; Amedi, Amir

2017-01-01

Background: One of the most stirring statistics in relation to the mobility of blind individuals is the high rate of upper body injuries, even when using the white-cane. Objective: We here addressed a rehabilitation- oriented challenge of providing a reliable tool for blind people to avoid waist-up obstacles, namely one of the impediments to their successful mobility using currently available methods (e.g., white-cane). Methods: We used the EyeCane, a device we developed which translates distances from several angles to haptic and auditory cues in an intuitive and unobtrusive manner, serving both as a primary and secondary mobility aid. We investigated the rehabilitation potential of such a device in facilitating visionless waist-up body protection. Results: After ∼5 minutes of training with the EyeCane blind participants were able to successfully detect and avoid obstacles waist-high and up. This was significantly higher than their success when using the white-cane alone. As avoidance of obstacles required participants to perform an additional cognitive process after their detection, the avoidance rate was significantly lower than the detection rate. Conclusion: Our work has demonstrated that the EyeCane has the potential to extend the sensory world of blind individuals by expanding their currently accessible inputs, and has offered them a new practical rehabilitation tool. PMID:28157111

Interventions for Behaviorally Disordered Students: A Quantitative Review and Methodological Critique.

ERIC Educational Resources Information Center

Skiba, Russell; Casey, Ann

1985-01-01

Results of three forms of meta-analysis on 41 studies involving behavior disorders revealed powerful effects of treatment: both interventions targeting classroom behavior and those attributable to a behavioral orientation were somewhat more powerful and robust. Methodological flaws, however, are cited. Recommendations for solidifying the research…

Different protocols for analyzing behavior and adaptability in obstacle crossing in Parkinson’s disease

PubMed Central

Mollaei, Nafiseh; Bicho, Estela; Sousa, Nuno; Gago, Miguel Fernandes

2017-01-01

Imbalance and tripping over obstacles as a result of altered gait in older adults, especially in patients with Parkinson’s disease (PD), are one of the most common causes of falls. During obstacle crossing, patients with PD modify their behavior in order to decrease the mechanical demands and enhance dynamic stability. Various descriptions of dynamic traits of gait that have been collected over longer periods, probably better synthesize the underlying structure and pattern of fluctuations in gait and can be more sensitive markers of aging or early neurological dysfunction and increased risk of falls. This confirmation challenges the clinimetric of different protocols and paradigms used for gait analysis up till now, in particular when analyzing obstacle crossing. The authors here present a critical review of current knowledge concerning the interplay between the cognition and gait in aging and PD, emphasizing the differences in gait behavior and adaptability while walking over different and challenging obstacle paradigms, and the implications of obstacle negotiation as a predictor of falls. Some evidence concerning the effectiveness of future rehabilitation protocols on reviving obstacle crossing behavior by trial and error relearning, taking advantage of dual-task paradigms, physical exercise, and virtual reality have been put forward in this article. PMID:29158667

[Obstacles perceived by nurses for evidence-based practice: a qualitative study].

PubMed

Sánchez-García, Inmaculada; López-Medina, Isabel M; Pancorbo-Hidalgo, Pedro L

2013-01-01

To examine the obstacles perceived by nurses to implement an evidence-based clinical practice. A qualitative study through semi-structured interviews conducted in 2010-2011 including 11 nurses purposively selected from public hospitals and community centres in Jaén and Córdoba (Spain). A content analysis was performed, using Miles and Huberman as a reference and comprising the following steps: data reduction, data presentation, and data conclusion/verification. Data saturation was reached in these categories (obstacles). The obstacles perceived by nurses to introduce an evidence-based clinical practice (EBCP) were grouped into 3 major categories: obstacles related with professionals (routine-based practice, unwilling and stagnant attitudes, and lack of training in EBCP), obstacles related to the social context (reluctance from other professionals and from patients or families), and obstacles related to the organization (obsolete cultures that do not promote innovation in nursing care). This study highlights the persistence of various factors that hinder the use of research findings in clinical practice. The results underline the need to change the culture of healthcare organizations, to motivate professionals, and to break some of the resistance attitudes that hinder the implementation of evidence-based practice. Copyright © 2012 Elsevier España, S.L. All rights reserved.

Selective processing of multiple features in the human brain: effects of feature type and salience.

PubMed

McGinnis, E Menton; Keil, Andreas

2011-02-09

Identifying targets in a stream of items at a given constant spatial location relies on selection of aspects such as color, shape, or texture. Such attended (target) features of a stimulus elicit a negative-going event-related brain potential (ERP), termed Selection Negativity (SN), which has been used as an index of selective feature processing. In two experiments, participants viewed a series of Gabor patches in which targets were defined as a specific combination of color, orientation, and shape. Distracters were composed of different combinations of color, orientation, and shape of the target stimulus. This design allows comparisons of items with and without specific target features. Consistent with previous ERP research, SN deflections extended between 160-300 ms. Data from the subsequent P3 component (300-450 ms post-stimulus) were also examined, and were regarded as an index of target processing. In Experiment A, predominant effects of target color on SN and P3 amplitudes were found, along with smaller ERP differences in response to variations of orientation and shape. Manipulating color to be less salient while enhancing the saliency of the orientation of the Gabor patch (Experiment B) led to delayed color selection and enhanced orientation selection. Topographical analyses suggested that the location of SN on the scalp reliably varies with the nature of the to-be-attended feature. No interference of non-target features on the SN was observed. These results suggest that target feature selection operates by means of electrocortical facilitation of feature-specific sensory processes, and that selective electrocortical facilitation is more effective when stimulus saliency is heightened.

"Think" versus "feel" framing effects in persuasion.

PubMed

Mayer, Nicole D; Tormala, Zakary L

2010-04-01

Three studies explored think ("I think . . . ") versus feel ("I feel . . . ") message framing effects on persuasion.The authors propose a matching hypothesis, suggesting that think framing will be more persuasive when the target attitude or message recipient is cognitively oriented, whereas feel framing will be more persuasive when the target attitude or message recipient is affectively oriented. Study 1 presented cognitively and affectively oriented individuals with a think- or feel-framed message. Study 2 primed cognitive or affective orientation and then presented a think- or feel-framed message. Study 3 presented male and female participants with an advertisement containing think- or feel-framed arguments. Results indicated that think (feel) framing was more persuasive when the target attitude or recipient was cognitively (affectively) oriented. Moreover, Study 2 demonstrated that this matching effect was mediated by processing fluency. Theoretical and practical implications are discussed.

Age-Related Physical Changes Interfere With Judgments of Male Sexual Orientation From Faces.

PubMed

Tskhay, Konstantin O; Krendl, Anne C; Rule, Nicholas O

2016-09-01

Although studies have shown that sexual orientation can be judged from faces, this research has not considered how age-related differences in perceivers or targets affect such judgments. In the current work, we evaluated whether accuracy differed among young adults (YA) and older adults (OA) for young and old men's faces by recruiting a sample of YA and OA in the lab, a community sample of sexual minority men, and a sample of online participants. We found that OA and YA judged sexual orientation with similar accuracy. Perceptions of gender atypicality mediated the difference in judging older and younger targets' sexual orientation. Although participants used positive affect to correctly discern sexual orientation regardless of target age, perceptions of masculinity were valid only for judgments of YA. © 2016 by the Society for Personality and Social Psychology, Inc.

Behavioural benefits of multisensory processing in ferrets.

PubMed

Hammond-Kenny, Amy; Bajo, Victoria M; King, Andrew J; Nodal, Fernando R

2017-01-01

Enhanced detection and discrimination, along with faster reaction times, are the most typical behavioural manifestations of the brain's capacity to integrate multisensory signals arising from the same object. In this study, we examined whether multisensory behavioural gains are observable across different components of the localization response that are potentially under the command of distinct brain regions. We measured the ability of ferrets to localize unisensory (auditory or visual) and spatiotemporally coincident auditory-visual stimuli of different durations that were presented from one of seven locations spanning the frontal hemifield. During the localization task, we recorded the head movements made following stimulus presentation, as a metric for assessing the initial orienting response of the ferrets, as well as the subsequent choice of which target location to approach to receive a reward. Head-orienting responses to auditory-visual stimuli were more accurate and faster than those made to visual but not auditory targets, suggesting that these movements were guided principally by sound alone. In contrast, approach-to-target localization responses were more accurate and faster to spatially congruent auditory-visual stimuli throughout the frontal hemifield than to either visual or auditory stimuli alone. Race model inequality analysis of head-orienting reaction times and approach-to-target response times indicates that different processes, probability summation and neural integration, respectively, are likely to be responsible for the effects of multisensory stimulation on these two measures of localization behaviour. © 2016 The Authors. European Journal of Neuroscience published by Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

On the rules of integration of crowded orientation signals.

PubMed

Põder, Endel

2012-01-01

Crowding is related to an integration of feature signals over an inappropriately large area in the visual periphery. The rules of this integration are still not well understood. This study attempts to understand how the orientation signals from the target and flankers are combined. A target Gabor, together with 2, 4, or 6 flanking Gabors, was briefly presented in a peripheral location (4° eccentricity). The observer's task was to identify the orientation of the target (eight-alternative forced-choice). Performance was found to be nonmonotonically dependent on the target-flanker orientation difference (a drop at intermediate differences). For small target-flanker differences, a strong assimilation bias was observed. An effect of the number of flankers was found for heterogeneous flankers only. It appears that different rules of integration are used, dependent on some salient aspects (target pop-out, homogeneity-heterogeneity) of the stimulus pattern. The strategy of combining simple rules may be explained by the goal of the visual system to encode potentially important aspects of a stimulus with limited processing resources and using statistical regularities of the natural visual environment.

Visual Search for Object Orientation Can Be Modulated by Canonical Orientation

ERIC Educational Resources Information Center

Ballaz, Cecile; Boutsen, Luc; Peyrin, Carole; Humphreys, Glyn W.; Marendaz, Christian

2005-01-01

The authors studied the influence of canonical orientation on visual search for object orientation. Displays consisted of pictures of animals whose axis of elongation was either vertical or tilted in their canonical orientation. Target orientation could be either congruent or incongruent with the object's canonical orientation. In Experiment 1,…

A system for the real-time display of radar and video images of targets

NASA Technical Reports Server (NTRS)

Allen, W. W.; Burnside, W. D.

1990-01-01

Described here is a software and hardware system for the real-time display of radar and video images for use in a measurement range. The main purpose is to give the reader a clear idea of the software and hardware design and its functions. This system is designed around a Tektronix XD88-30 graphics workstation, used to display radar images superimposed on video images of the actual target. The system's purpose is to provide a platform for tha analysis and documentation of radar images and their associated targets in a menu-driven, user oriented environment.

Why Implementing History and Philosophy in School Science Education is a Challenge: An Analysis of Obstacles

NASA Astrophysics Data System (ADS)

Höttecke, Dietmar; Silva, Cibelle Celestino

2011-03-01

Teaching and learning with history and philosophy of science (HPS) has been, and continues to be, supported by science educators. While science education standards documents in many countries also stress the importance of teaching and learning with HPS, the approach still suffers from ineffective implementation in school science teaching. In order to better understand this problem, an analysis of the obstacles of implementing HPS into classrooms was undertaken. The obstacles taken into account were structured in four groups: 1. culture of teaching physics, 2. teachers' skills, epistemological and didactical attitudes and beliefs, 3. institutional framework of science teaching, and 4. textbooks as fundamental didactical support. Implications for more effective implementation of HPS are presented, taking the social nature of educational systems into account.

Supraliminal But Not Subliminal Distracters Bias Working Memory Recall

PubMed Central

2015-01-01

Information of which observers are not consciously aware can nevertheless influence perceptual processes. Whether subliminal information might exert an influence on working memory (WM) representations is less clear, and relatively few studies have examined the interactions between subliminal and supraliminal information in WM. We present 3 experiments examining this issue. Experiments 1a and b replicated the finding that orientation stimuli can influence behavior subliminally in a visuomotor priming task. Experiments 2 and 3 used the same orientation stimuli, but participants had to remember a target orientation and report it back by adjusting a probe orientation after a memory delay. Before or after presentation of the target orientation, a subliminal or supraliminal distracter orientation was presented that was either irrelevant for task completion and never had to be reported (Experiment 2), or was relevant for task completion because it had to be reported on some trials (Experiment 3). In both experiments, presentation of a supraliminal distracter influenced WM recall of the target orientation. When the distracter was presented subliminally, however, there was no bias in orientation recall. These results suggest that information stored in WM is protected from influences of subliminal stimuli, while online information processing is modulated by subliminal information. PMID:25867502

People with diabetic peripheral neuropathy display a decreased stepping accuracy during walking: potential implications for risk of tripping.

PubMed

Handsaker, J C; Brown, S J; Bowling, F L; Marple-Horvat, D E; Boulton, A J M; Reeves, N D

2016-05-01

To examine the stepping accuracy of people with diabetes and diabetic peripheral neuropathy. Fourteen patients with diabetic peripheral neuropathy (DPN), 12 patients with diabetes but no neuropathy (D) and 10 healthy non-diabetic control participants (C). Accuracy of stepping was measured whilst the participants walked along a walkway consisting of 18 stepping targets. Preliminary data on visual gaze characteristics were also captured in a subset of participants (diabetic peripheral neuropathy group: n = 4; diabetes-alone group: n = 4; and control group: n = 4) during the same task. Patients in the diabetic peripheral neuropathy group, and patients in the diabetes-alone group were significantly less accurate at stepping on targets than were control subjects (P < 0.05). Preliminary visual gaze analysis identified that patients diabetic peripheral neuropathy were slower to look between targets, resulting in less time being spent looking at a target before foot-target contact. Impaired motor control is theorized to be a major factor underlying the changes in stepping accuracy, and potentially altered visual gaze behaviour may also play a role. Reduced stepping accuracy may indicate a decreased ability to control the placement of the lower limbs, leading to patients with neuropathy potentially being less able to avoid observed obstacles during walking. © 2015 Diabetes UK.

The effects of paradigmatic orientations of education research and discourse

NASA Astrophysics Data System (ADS)

Smithson, John Lawrence

This essay presents an examination of contemporary disputes over methodological and epistemological foundations underlying inquiry within the field of education research; investigating the obstacles to communication and understanding found in scholarly exchanges occurring across competing paradigmatic orientations. Terminological challenges to cross-paradigmatic communication are examined, identifying three specific terminological difficulties, referred to as homonym, contextual, and onti-stemic problems. Nicholas Burbules' model of dialogue, based upon characteristics of convergence, divergence, inclusive and critical traits, is adopted and applied to a sample of cross-paradigmatic exchanges found in recent educational research journals. Examination of those exchanges reveals certain strategies associated with cross-paradigmatic communication. These strategies, labeled as trivialization, caricaturization, and re-direction, are shown to be detrimental to the mutual understanding of the interlocutors. The model is then extended to address examples of paradigmatic orientations within methodological and epistemological contexts in order to consider the relationship between the various orientations represented in the literature of interest. Methodological and epistemological orientations are shown to be loosely coupled, with unexpected shifts in paradigmatic values found among researchers' methodological and epistemological commitments. Finally, the nature of the relationship between competing paradigmatic orientations is examined, with particular attention given to four types of incommensurability (ontological, linguistic, epistemological, and values incommensurability). I conclude that, though difficult, cross-paradigmatic communication is necessary in order to provide a multi-paradigmatic perspective that takes us beyond the fractured picture of educational phenomena available from current research approaches.

Embodied memory allows accurate and stable perception of hidden objects despite orientation change.

PubMed

Pan, Jing Samantha; Bingham, Ned; Bingham, Geoffrey P

2017-07-01

Rotating a scene in a frontoparallel plane (rolling) yields a change in orientation of constituent images. When using only information provided by static images to perceive a scene after orientation change, identification performance typically decreases (Rock & Heimer, 1957). However, rolling generates optic flow information that relates the discrete, static images (before and after the change) and forms an embodied memory that aids recognition. The embodied memory hypothesis predicts that upon detecting a continuous spatial transformation of image structure, or in other words, seeing the continuous rolling process and objects undergoing rolling observers should accurately perceive objects during and after motion. Thus, in this case, orientation change should not affect performance. We tested this hypothesis in three experiments and found that (a) using combined optic flow and image structure, participants identified locations of previously perceived but currently occluded targets with great accuracy and stability (Experiment 1); (b) using combined optic flow and image structure information, participants identified hidden targets equally well with or without 30° orientation changes (Experiment 2); and (c) when the rolling was unseen, identification of hidden targets after orientation change became worse (Experiment 3). Furthermore, when rolling was unseen, although target identification was better when participants were told about the orientation change than when they were not told, performance was still worse than when there was no orientation change. Therefore, combined optic flow and image structure information, not mere knowledge about the rolling, enables accurate and stable perception despite orientation change. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

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.

Obstacles to Developing Digital Literacy on the Internet in Middle School Science Instruction

ERIC Educational Resources Information Center

Colwell, Jamie; Hunt-Barron, Sarah; Reinking, David

2013-01-01

Obstacles, and instructional responses to them, that emerged in two middle school science classes during a formative experiment investigating Internet Reciprocal Teaching (IRT), an instructional intervention aimed at increasing digital literacy on the Internet, are reported in this manuscript. Analysis of qualitative data revealed that IRT enabled…

Precision Pointing Control System (PPCS) system design and analysis. [for gimbaled experiment platforms

NASA Technical Reports Server (NTRS)

Frew, A. M.; Eisenhut, D. F.; Farrenkopf, R. L.; Gates, R. F.; Iwens, R. P.; Kirby, D. K.; Mann, R. J.; Spencer, D. J.; Tsou, H. S.; Zaremba, J. G.

1972-01-01

The precision pointing control system (PPCS) is an integrated system for precision attitude determination and orientation of gimbaled experiment platforms. The PPCS concept configures the system to perform orientation of up to six independent gimbaled experiment platforms to design goal accuracy of 0.001 degrees, and to operate in conjunction with a three-axis stabilized earth-oriented spacecraft in orbits ranging from low altitude (200-2500 n.m., sun synchronous) to 24 hour geosynchronous, with a design goal life of 3 to 5 years. The system comprises two complementary functions: (1) attitude determination where the attitude of a defined set of body-fixed reference axes is determined relative to a known set of reference axes fixed in inertial space; and (2) pointing control where gimbal orientation is controlled, open-loop (without use of payload error/feedback) with respect to a defined set of body-fixed reference axes to produce pointing to a desired target.

Query-oriented evidence extraction to support evidence-based medicine practice.

PubMed

Sarker, Abeed; Mollá, Diego; Paris, Cecile

2016-02-01

Evidence-based medicine practice requires medical practitioners to rely on the best available evidence, in addition to their expertise, when making clinical decisions. The medical domain boasts a large amount of published medical research data, indexed in various medical databases such as MEDLINE. As the size of this data grows, practitioners increasingly face the problem of information overload, and past research has established the time-associated obstacles faced by evidence-based medicine practitioners. In this paper, we focus on the problem of automatic text summarisation to help practitioners quickly find query-focused information from relevant documents. We utilise an annotated corpus that is specialised for the task of evidence-based summarisation of text. In contrast to past summarisation approaches, which mostly rely on surface level features to identify salient pieces of texts that form the summaries, our approach focuses on the use of corpus-based statistics, and domain-specific lexical knowledge for the identification of summary contents. We also apply a target-sentence-specific summarisation technique that reduces the problem of underfitting that persists in generic summarisation models. In automatic evaluations run over a large number of annotated summaries, our extractive summarisation technique statistically outperforms various baseline and benchmark summarisation models with a percentile rank of 96.8%. A manual evaluation shows that our extractive summarisation approach is capable of selecting content with high recall and precision, and may thus be used to generate bottom-line answers to practitioners' queries. Our research shows that the incorporation of specialised data and domain-specific knowledge can significantly improve text summarisation performance in the medical domain. Due to the vast amounts of medical text available, and the high growth of this form of data, we suspect that such summarisation techniques will address the time-related obstacles associated with evidence-based medicine. Copyright © 2015 Elsevier Inc. All rights reserved.

Optimization of Self-Directed Target Coverage in Wireless Multimedia Sensor Network

PubMed Central

Yang, Yang; Wang, Yufei; Pi, Dechang; Wang, Ruchuan

2014-01-01

Video and image sensors in wireless multimedia sensor networks (WMSNs) have directed view and limited sensing angle. So the methods to solve target coverage problem for traditional sensor networks, which use circle sensing model, are not suitable for WMSNs. Based on the FoV (field of view) sensing model and FoV disk model proposed, how expected multimedia sensor covers the target is defined by the deflection angle between target and the sensor's current orientation and the distance between target and the sensor. Then target coverage optimization algorithms based on expected coverage value are presented for single-sensor single-target, multisensor single-target, and single-sensor multitargets problems distinguishingly. Selecting the orientation that sensor rotated to cover every target falling in the FoV disk of that sensor for candidate orientations and using genetic algorithm to multisensor multitargets problem, which has NP-complete complexity, then result in the approximated minimum subset of sensors which covers all the targets in networks. Simulation results show the algorithm's performance and the effect of number of targets on the resulting subset. PMID:25136667

Pigeons steer like helicopters and generate down- and upstroke lift during low speed turns.

PubMed

Ros, Ivo G; Bassman, Lori C; Badger, Marc A; Pierson, Alyssa N; Biewener, Andrew A

2011-12-13

Turning is crucial for animals, particularly during predator-prey interactions and to avoid obstacles. For flying animals, turning consists of changes in (i) flight trajectory, or path of travel, and (ii) body orientation, or 3D angular position. Changes in flight trajectory can only be achieved by modulating aerodynamic forces relative to gravity. How birds coordinate aerodynamic force production relative to changes in body orientation during turns is key to understanding the control strategies used in avian maneuvering flight. We hypothesized that pigeons produce aerodynamic forces in a uniform direction relative to their bodies, requiring changes in body orientation to redirect those forces to turn. Using detailed 3D kinematics and body mass distributions, we examined net aerodynamic forces and body orientations in slowly flying pigeons (Columba livia) executing level 90° turns. The net aerodynamic force averaged over the downstroke was maintained in a fixed direction relative to the body throughout the turn, even though the body orientation of the birds varied substantially. Early in the turn, changes in body orientation primarily redirected the downstroke aerodynamic force, affecting the bird's flight trajectory. Subsequently, the pigeon mainly reacquired the body orientation used in forward flight without affecting its flight trajectory. Surprisingly, the pigeon's upstroke generated aerodynamic forces that were approximately 50% of those generated during the downstroke, nearly matching the relative upstroke forces produced by hummingbirds. Thus, pigeons achieve low speed turns much like helicopters, by using whole-body rotations to alter the direction of aerodynamic force production to change their flight trajectory.

Pigeons steer like helicopters and generate down- and upstroke lift during low speed turns

PubMed Central

Ros, Ivo G.; Bassman, Lori C.; Badger, Marc A.; Pierson, Alyssa N.; Biewener, Andrew A.

2011-01-01

Turning is crucial for animals, particularly during predator–prey interactions and to avoid obstacles. For flying animals, turning consists of changes in (i) flight trajectory, or path of travel, and (ii) body orientation, or 3D angular position. Changes in flight trajectory can only be achieved by modulating aerodynamic forces relative to gravity. How birds coordinate aerodynamic force production relative to changes in body orientation during turns is key to understanding the control strategies used in avian maneuvering flight. We hypothesized that pigeons produce aerodynamic forces in a uniform direction relative to their bodies, requiring changes in body orientation to redirect those forces to turn. Using detailed 3D kinematics and body mass distributions, we examined net aerodynamic forces and body orientations in slowly flying pigeons (Columba livia) executing level 90° turns. The net aerodynamic force averaged over the downstroke was maintained in a fixed direction relative to the body throughout the turn, even though the body orientation of the birds varied substantially. Early in the turn, changes in body orientation primarily redirected the downstroke aerodynamic force, affecting the bird’s flight trajectory. Subsequently, the pigeon mainly reacquired the body orientation used in forward flight without affecting its flight trajectory. Surprisingly, the pigeon’s upstroke generated aerodynamic forces that were approximately 50% of those generated during the downstroke, nearly matching the relative upstroke forces produced by hummingbirds. Thus, pigeons achieve low speed turns much like helicopters, by using whole-body rotations to alter the direction of aerodynamic force production to change their flight trajectory. PMID:22123982

Measurement of functional capacity requirements to aid in development of an occupation-specific rehabilitation training program to help firefighters with cardiac disease safely return to work.

PubMed

Adams, Jenny; Roberts, Joanne; Simms, Kay; Cheng, Dunlei; Hartman, Julie; Bartlett, Charles

2009-03-15

We designed a study to measure the functional capacity requirements of firefighters to aid in the development of an occupation-specific training program in cardiac rehabilitation; 23 healthy male firefighters with no history of heart disease completed a fire and rescue obstacle course that simulated 7 common firefighting tasks. They wore complete personal protective equipment and portable metabolic instruments that included a data collection mask. We monitored each subject's oxygen consumption (VO(2)) and working heart rate, then calculated age-predicted maximum heart rates (220 - age) and training target heart rates (85% of age-predicted maximum heart rate). During performance of the obstacle course, the subjects' mean working heart rates and peak heart rates were higher than the calculated training target heart rates (t(22) = 5.69 [working vs target, p <0.001] and t(22) = 15.14 [peak vs target, p <0.001]). These findings, with mean results for peak VO(2) (3,447 ml/min) and metabolic equivalents (11.9 METs), show that our subjects' functional capacity greatly exceeded that typically attained by patients in traditional cardiac rehabilitation programs (5 to 8 METs). In conclusion, our results indicate the need for intense, occupation-specific cardiac rehabilitation training that will help firefighters safely return to work after a cardiac event.

Target-oriented imaging of hydraulic fractures by applying the staining algorithm for downhole microseismic migration

NASA Astrophysics Data System (ADS)

Lin, Ye; Zhang, Haijiang; Jia, Xiaofeng

2018-03-01

For microseismic monitoring of hydraulic fracturing, microseismic migration can be used to image the fracture network with scattered microseismic waves. Compared with conventional microseismic location-based fracture characterization methods, microseismic migration can better constrain the stimulated reservoir volume regardless of the completeness of detected and located microseismic sources. However, the imaging results from microseismic migration may suffer from the contamination of other structures and thus the target fracture zones may not be illuminated properly. To solve this issue, in this study we propose a target-oriented staining algorithm for microseismic reverse-time migration. In the staining algorithm, the target area is first stained by constructing an imaginary velocity field and then a synchronized source wavefield only concerning the target structure is produced. As a result, a synchronized image from imaging with the synchronized source wavefield mainly contains the target structures. Synthetic tests based on a downhole microseismic monitoring system show that the target-oriented microseismic reverse-time migration method improves the illumination of target areas.

Involuntary orienting of attention to a sound desynchronizes the occipital alpha rhythm and improves visual perception.

PubMed

Feng, Wenfeng; Störmer, Viola S; Martinez, Antigona; McDonald, John J; Hillyard, Steven A

2017-04-15

Directing attention voluntarily to the location of a visual target results in an amplitude reduction (desynchronization) of the occipital alpha rhythm (8-14Hz), which is predictive of improved perceptual processing of the target. Here we investigated whether modulations of the occipital alpha rhythm triggered by the involuntary orienting of attention to a salient but spatially non-predictive sound would similarly influence perception of a subsequent visual target. Target discrimination was more accurate when a sound preceded the target at the same location (validly cued trials) than when the sound was on the side opposite to the target (invalidly cued trials). This behavioral effect was accompanied by a sound-induced desynchronization of the alpha rhythm over the lateral occipital scalp. The magnitude of alpha desynchronization over the hemisphere contralateral to the sound predicted correct discriminations of validly cued targets but not of invalidly cued targets. These results support the conclusion that cue-induced alpha desynchronization over the occipital cortex is a manifestation of a general priming mechanism that improves visual processing and that this mechanism can be activated either by the voluntary or involuntary orienting of attention. Further, the observed pattern of alpha modulations preceding correct and incorrect discriminations of valid and invalid targets suggests that involuntary orienting to the non-predictive sound has a rapid and purely facilitatory influence on processing targets on the cued side, with no inhibitory influence on targets on the opposite side. Copyright © 2017 Elsevier Inc. All rights reserved.

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.

Robotic Follow Algorithm

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

2005-03-30

The Robotic Follow Algorithm enables allows any robotic vehicle to follow a moving target while reactively choosing a route around nearby obstacles. The robotic follow behavior can be used with different camera systems and can be used with thermal or visual tracking as well as other tracking methods such as radio frequency tags.

Transformation of the California mental health system: stakeholder-driven planning as a transformational activity.

PubMed

Cashin, Cheryl; Scheffler, Richard; Felton, Mistique; Adams, Neal; Miller, Leonard

2008-10-01

This study describes strategies developed by California counties to transform their mental health systems under the 2004 Mental Health Services Act (MHSA). This voter initiative places a 1% tax on annual incomes over $1 million; tax monies are earmarked to transform county-operated mental health services into systems that are oriented more toward recovery. MHSA implementation itself can be considered "transformational" by balancing greater standardization of mental health service delivery in the state with a locally driven planning process. A qualitative content analysis of the three-year plans submitted by 12 counties to receive funds under MHSA was conducted to identify common themes, as well as innovative approaches. These 12 (out of 58) counties were chosen to represent both small and large counties, as well as geographic diversity, and they represent 62.3% of the state population. This analysis showed that the state guidelines and local planning process generated consistency across counties in establishing full-service partnerships with a "whatever it takes" approach to providing goal-directed services and supports to consumers and their families. There was, however, little convergence around the specific strategies to achieve this vision, reflecting both the local planning process and a relative lack of clear policy and guidance on evidence-based practices. There are many obstacles to the successful implementation of these ambitious plans. However, the state-guided, but stakeholder-driven, transformation in California appears to generate innovative approaches to recovery-oriented services, involve consumers and family members in service planning and delivery, and build community partnerships that create new opportunities for consumers to meet their recovery goals.

Target-distractor similarity has a larger impact on visual search in school-age children than spacing.

PubMed

Huurneman, Bianca; Boonstra, F Nienke

2015-01-22

In typically developing children, crowding decreases with increasing age. The influence of target-distractor similarity with respect to orientation and element spacing on visual search performance was investigated in 29 school-age children with normal vision (4- to 6-year-olds [N = 16], 7- to 8-year-olds [N = 13]). Children were instructed to search for a target E among distractor Es (feature search: all flanking Es pointing right; conjunction search: flankers in three orientations). Orientation of the target was manipulated in four directions: right (target absent), left (inversed), up, and down (vertical). Spacing was varied in four steps: 0.04°, 0.5°, 1°, and 2°. During feature search, high target-distractor similarity had a stronger impact on performance than spacing: Orientation affected accuracy until spacing was 1°, and spacing only influenced accuracy for identifying inversed targets. Spatial analyses showed that orientation affected oculomotor strategy: Children made more fixations in the "inversed" target area (4.6) than the vertical target areas (1.8 and 1.9). Furthermore, age groups differed in fixation duration: 4- to 6-year-old children showed longer fixation durations than 7- to 8-year-olds at the two largest element spacings (p = 0.039 and p = 0.027). Conjunction search performance was unaffected by spacing. Four conclusions can be drawn from this study: (a) Target-distractor similarity governs visual search performance in school-age children, (b) children make more fixations in target areas when target-distractor similarity is high, (c) 4- to 6-year-olds show longer fixation durations than 7- to 8-year-olds at 1° and 2° element spacing, and (d) spacing affects feature but not conjunction search-a finding that might indicate top-down control ameliorates crowding in children. © 2015 ARVO.

Foot strike patterns after obstacle clearance during running.

PubMed

Scholten, Shane D; Stergiou, Nicholas; Hreljac, Alan; Houser, Jeremy; Blanke, Daniel; Alberts, L Russell

2002-01-01

Running over obstacles of sufficient height requires heel strike (HS) runners to make a transition in landing strategy to a forefoot (FF) strike, resulting in similar ground reaction force patterns to those observed while landing from a jump. Identification of the biomechanical variables that distinguish between the landing strategies may offer some insight into the reasons that the transition occurs. The purpose of this study was to investigate the difference in foot strike patterns and kinetic parameters of heel strike runners between level running and running over obstacles of various heights. Ten heel strike subjects ran at their self-selected pace under seven different conditions: unperturbed running (no obstacle) and over obstacles of six different heights (10%, 12.5%, 15%, 17.5%, 20%, and 22.5% of their standing height). The obstacle was placed directly before a Kistler force platform. Repeated measures ANOVAs were performed on the subject means of selected kinetic parameters. The statistical analysis revealed significant differences (P < 0.004) for all of the parameters analyzed. The evaluation of the center of pressure and the ground reaction forces indicated that the foot strike patterns were affected by the increased obstacle height. Between the 12.5% and 15% obstacle conditions, the group response changed from a heel strike to a forefoot strike pattern. At height > 15%, the pattern was more closely related to the foot strike patterns found in jumping activities. This strategy change may represent a gait transition effected as a mechanism to protect against increased impact forces. Greater involvement of the ankle and the calf muscles could have assisted in attenuating the increased impact forces while maintaining speed after clearing the obstacle.

Promoting Curriculum Reforms in the Context of a Political Transition: An Analysis of Hong Kong's Experience.

ERIC Educational Resources Information Center

Morris, Paul

2002-01-01

Analyzes creation and implementation of Hong Kong's Target Oriented Curriculum (TOC), an education reform effort, in light of the country's transition to Chinese rule in 1997. Examines TOC's origins, its nature, means of implementation, and its impact. Discusses tension between "policy intent" and "policy actions," and…

Sensitizing Black Adult and Youth Consumers to Targeted Food Marketing Tactics in Their Environments

PubMed Central

Isselmann DiSantis, Katherine; Kumanyika, Shiriki; Rohm Young, Deborah; Grier, Sonya A.; Lassiter, Vikki

2017-01-01

Food marketing environments of Black American consumers are heavily affected by ethnically-targeted marketing of sugar sweetened beverages, fast foods, and other products that may contribute to caloric overconsumption. This qualitative study assessed Black consumers’ responses to targeted marketing. Black adults (2 mixed gender groups; total n = 30) and youth (2 gender specific groups; total n = 35) from two U.S. communities participated before and after a sensitization procedure—a critical practice used to understand social justice concerns. Pre-sensitization focus groups elicited responses to scenarios about various targeted marketing tactics. Participants were then given an informational booklet about targeted marketing to Black Americans, and all returned for the second (post-sensitization) focus group one week later. Conventional qualitative content analysis of transcripts identified several salient themes: seeing the marketer’s perspective (“it’s about demand”; “consumers choose”), respect for community (“marketers are setting us up for failure”; “making wrong assumptions”), and food environments as a social justice issue (“no one is watching the door”; “I didn’t realize”). Effects of sensitization were reflected in participants’ stated reactions to the information in the booklet, and also in the relative occurrence of marketer-oriented themes and social justice-oriented themes, respectively, less and more after sensitization. PMID:29109377

Sensitizing Black Adult and Youth Consumers to Targeted Food Marketing Tactics in Their Environments.

PubMed

Isselmann DiSantis, Katherine; Kumanyika, Shiriki; Carter-Edwards, Lori; Rohm Young, Deborah; Grier, Sonya A; Lassiter, Vikki

2017-10-29

Food marketing environments of Black American consumers are heavily affected by ethnically-targeted marketing of sugar sweetened beverages, fast foods, and other products that may contribute to caloric overconsumption. This qualitative study assessed Black consumers' responses to targeted marketing. Black adults (2 mixed gender groups; total n = 30) and youth (2 gender specific groups; total n = 35) from two U.S. communities participated before and after a sensitization procedure-a critical practice used to understand social justice concerns. Pre-sensitization focus groups elicited responses to scenarios about various targeted marketing tactics. Participants were then given an informational booklet about targeted marketing to Black Americans, and all returned for the second (post-sensitization) focus group one week later. Conventional qualitative content analysis of transcripts identified several salient themes: seeing the marketer's perspective ("it's about demand"; "consumers choose"), respect for community ("marketers are setting us up for failure"; "making wrong assumptions"), and food environments as a social justice issue ("no one is watching the door"; "I didn't realize"). Effects of sensitization were reflected in participants' stated reactions to the information in the booklet, and also in the relative occurrence of marketer-oriented themes and social justice-oriented themes, respectively, less and more after sensitization.

Audible sonar images generated with proprioception for target analysis.

PubMed

Kuc, Roman B

2017-05-01

Some blind humans have demonstrated the ability to detect and classify objects with echolocation using palatal clicks. An audible-sonar robot mimics human click emissions, binaural hearing, and head movements to extract interaural time and level differences from target echoes. Targets of various complexity are examined by transverse displacements of the sonar and by target pose rotations that model movements performed by the blind. Controlled sonar movements executed by the robot provide data that model proprioception information available to blind humans for examining targets from various aspects. The audible sonar uses this sonar location and orientation information to form two-dimensional target images that are similar to medical diagnostic ultrasound tomograms. Simple targets, such as single round and square posts, produce distinguishable and recognizable images. More complex targets configured with several simple objects generate diffraction effects and multiple reflections that produce image artifacts. The presentation illustrates the capabilities and limitations of target classification from audible sonar images.

A paradigm shift in the evaluation of information technology in health care.

PubMed

Bonneville, Luc

2005-08-01

This paper examines the notion of productivity, which underlies the reorganization of Quebec's health care system around an information technology-driven virage ambulatoire, or shift to ambulatory (outpatient) care. The reorganization may be traced to a policy decision to address the health care's productivity crisis, a crisis diagnosed in the 1970s based on macroeconomic expenditure trend lines highlighting the "obstacle" to economic growth and to balanced budgets. The information technology-driven virage ambulatoire is aimed at a structural reorganization, based on the principle of: boosting productivity in a service- or information-based economy. The State, thus, relied on analytic categories developed for a particular mode of economic analysis to lead a hospital restructuring program oriented around information technology-based ambulatory care. The result was a refocus from clinical and therapeutic efficiency to administrative imperatives of time, cost, and optimization. Hence, Québec moved to neoliberal productivist system in which clinical and therapeutic effectiveness are subordinated to economic imperatives.

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.

Obstacles to integrated pest management adoption in developing countries

PubMed Central

Parsa, Soroush; Morse, Stephen; Bonifacio, Alejandro; Chancellor, Timothy C. B.; Condori, Bruno; Crespo-Pérez, Verónica; Hobbs, Shaun L. A.; Kroschel, Jürgen; Ba, Malick N.; Rebaudo, François; Sherwood, Stephen G.; Vanek, Steven J.; Faye, Emile; Herrera, Mario A.; Dangles, Olivier

2014-01-01

Despite its theoretical prominence and sound principles, integrated pest management (IPM) continues to suffer from anemic adoption rates in developing countries. To shed light on the reasons, we surveyed the opinions of a large and diverse pool of IPM professionals and practitioners from 96 countries by using structured concept mapping. The first phase of this method elicited 413 open-ended responses on perceived obstacles to IPM. Analysis of responses revealed 51 unique statements on obstacles, the most frequent of which was “insufficient training and technical support to farmers.” Cluster analyses, based on participant opinions, grouped these unique statements into six themes: research weaknesses, outreach weaknesses, IPM weaknesses, farmer weaknesses, pesticide industry interference, and weak adoption incentives. Subsequently, 163 participants rated the obstacles expressed in the 51 unique statements according to importance and remediation difficulty. Respondents from developing countries and high-income countries rated the obstacles differently. As a group, developing-country respondents rated “IPM requires collective action within a farming community” as their top obstacle to IPM adoption. Respondents from high-income countries prioritized instead the “shortage of well-qualified IPM experts and extensionists.” Differential prioritization was also evident among developing-country regions, and when obstacle statements were grouped into themes. Results highlighted the need to improve the participation of stakeholders from developing countries in the IPM adoption debate, and also to situate the debate within specific regional contexts. PMID:24567400

How Magnetic Disturbance Influences the Attitude and Heading in Magnetic and Inertial Sensor-Based Orientation Estimation

PubMed Central

Li, Qingguo

2017-01-01

With the advancements in micro-electromechanical systems (MEMS) technologies, magnetic and inertial sensors are becoming more and more accurate, lightweight, smaller in size as well as low-cost, which in turn boosts their applications in human movement analysis. However, challenges still exist in the field of sensor orientation estimation, where magnetic disturbance represents one of the obstacles limiting their practical application. The objective of this paper is to systematically analyze exactly how magnetic disturbances affects the attitude and heading estimation for a magnetic and inertial sensor. First, we reviewed four major components dealing with magnetic disturbance, namely decoupling attitude estimation from magnetic reading, gyro bias estimation, adaptive strategies of compensating magnetic disturbance and sensor fusion algorithms. We review and analyze the features of existing methods of each component. Second, to understand each component in magnetic disturbance rejection, four representative sensor fusion methods were implemented, including gradient descent algorithms, improved explicit complementary filter, dual-linear Kalman filter and extended Kalman filter. Finally, a new standardized testing procedure has been developed to objectively assess the performance of each method against magnetic disturbance. Based upon the testing results, the strength and weakness of the existing sensor fusion methods were easily examined, and suggestions were presented for selecting a proper sensor fusion algorithm or developing new sensor fusion method. PMID:29283432

Special school teachers require more goal-oriented collaboration with psychiatric professionals in Northern Finland.

PubMed

Pönkkö, Maija-Leena; Taanila, Anja; Ebeling, Hanna

2003-03-01

The problems of children and adolescents have increased in number and severity during the last years. The purpose of this study was to elicit the views of special school teachers in the Oulu Province in Finland concerning their pupils' problems and the need, use and adequacy of relevant psychiatric services. The information was collected from the Northern Ostrobothnia Hospital District in 1998 in Finland and responses were obtained from the 37 (97.4%) special schools. The data were analysed using the content analysis method. Special-needs pupils had various behavioural and emotional problems that made it difficult for them to learn and for the teachers to teach. According to the teachers, the major obstacles in the process of helping special-needs pupils were the delayed admission for treatment and the lack of information necessary for the pupils' school work and goal-oriented aftercare, although there were also favourable experiences of functional co-operation and availability of useful information. Some schools lacked a reliable network for helping pupilsand supporting teachers. The Finnish legislation on basic education obliges the providers of education to provide rehabilitation in connection with special education and to arrange relevant development, counselling and support services. The rehabilitation of special-need pupils and the collaboration between school and mental health authorities is not optimally realised in spite of the legislation.

Feature-level sentiment analysis by using comparative domain corpora

NASA Astrophysics Data System (ADS)

Quan, Changqin; Ren, Fuji

2016-06-01

Feature-level sentiment analysis (SA) is able to provide more fine-grained SA on certain opinion targets and has a wider range of applications on E-business. This study proposes an approach based on comparative domain corpora for feature-level SA. The proposed approach makes use of word associations for domain-specific feature extraction. First, we assign a similarity score for each candidate feature to denote its similarity extent to a domain. Then we identify domain features based on their similarity scores on different comparative domain corpora. After that, dependency grammar and a general sentiment lexicon are applied to extract and expand feature-oriented opinion words. Lastly, the semantic orientation of a domain-specific feature is determined based on the feature-oriented opinion lexicons. In evaluation, we compare the proposed method with several state-of-the-art methods (including unsupervised and semi-supervised) using a standard product review test collection. The experimental results demonstrate the effectiveness of using comparative domain corpora.

Control of Oriented Tissue Growth through Repression of Organ Boundary Genes Promotes Stem Morphogenesis.

PubMed

Bencivenga, Stefano; Serrano-Mislata, Antonio; Bush, Max; Fox, Samantha; Sablowski, Robert

2016-10-24

The origin of the stem is a major but poorly understood aspect of plant development, partly because the stem initiates in a relatively inaccessible region of the shoot apical meristem called the rib zone (RZ). We developed quantitative 3D image analysis and clonal analysis tools, which revealed that the Arabidopsis homeodomain protein REPLUMLESS (RPL) establishes distinct patterns of oriented cell division and growth in the central and peripheral regions of the RZ. A genome-wide screen for target genes connected RPL directly to many of the key shoot development pathways, including the development of organ boundaries; accordingly, mutation of the organ boundary gene LIGHT-SENSITIVE HYPOCOTYL 4 restored RZ function and stem growth in the rpl mutant. Our work opens the way to study a developmental process of importance to crop improvement and highlights how apparently simple changes in 3D organ growth can reflect more complex internal changes in oriented cell activities. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Parenthood as a Terror Management Mechanism: The Moderating Role of Attachment Orientations.

PubMed

Yaakobi, Erez; Mikulincer, Mario; Shaver, Phillip R

2014-06-01

Six studies examined the hypothesis that parenthood serves a terror management function, with effects that are moderated by attachment orientations. In Studies 1 and 2, mortality salience, as compared with control conditions, increased the self-reported vividness and implicit accessibility of parenthood-related cognitions. In Studies 3 and 4, activating parenthood-related thoughts reduced death-thought accessibility and romantic intimacy following mortality salience. In Study 5, heightening the salience of parenthood-related obstacles increased death-thought accessibility. Across the five studies, the effects were significant mainly among participants who scored relatively low on avoidant attachment. In Study 6, avoidant people also reacted to mortality salience with more positive parenthood-related cognitions following an experimental manipulation that made parenthood compatible with their core strivings. Overall, the findings suggest that parenthood can have an anxiety-buffering effect that is moderated by attachment-related avoidance. © 2014 by the Society for Personality and Social Psychology, Inc.

Not All Attention Orienting is Created Equal: Recognition Memory is Enhanced When Attention Orienting Involves Distractor Suppression

PubMed Central

Markant, Julie; Worden, Michael S.; Amso, Dima

2015-01-01

Learning through visual exploration often requires orienting of attention to meaningful information in a cluttered world. Previous work has shown that attention modulates visual cortex activity, with enhanced activity for attended targets and suppressed activity for competing inputs, thus enhancing the visual experience. Here we examined the idea that learning may be engaged differentially with variations in attention orienting mechanisms that drive driving eye movements during visual search and exploration. We hypothesized that attention orienting mechanisms that engaged suppression of a previously attended location will boost memory encoding of the currently attended target objects to a greater extent than those that involve target enhancement alone To test this hypothesis we capitalized on the classic spatial cueing task and the inhibition of return (IOR) mechanism (Posner, Rafal, & Choate, 1985; Posner, 1980) to demonstrate that object images encoded in the context of concurrent suppression at a previously attended location were encoded more effectively and remembered better than those encoded without concurrent suppression. Furthermore, fMRI analyses revealed that this memory benefit was driven by attention modulation of visual cortex activity, as increased suppression of the previously attended location in visual cortex during target object encoding predicted better subsequent recognition memory performance. These results suggest that not all attention orienting impacts learning and memory equally. PMID:25701278

Obstacles Related to Structuring for Mathematization Encountered by Students When Solving Physics Problems

ERIC Educational Resources Information Center

Niss, Martin

2017-01-01

This paper studies the cognitive obstacles related to one aspect of mathematization in physics problem-solving, namely, what might be called "structuring for mathematization," where the problem situation is structured in such a way that a translation to a mathematical universe can be done. We report the results of an analysis of four…

Human centromedian-parafascicular complex signals sensory cues for goal-oriented behavior selection.

PubMed

Schepers, Inga M; Beck, Anne-Kathrin; Bräuer, Susann; Schwabe, Kerstin; Abdallat, Mahmoud; Sandmann, Pascale; Dengler, Reinhard; Rieger, Jochem W; Krauss, Joachim K

2017-05-15

Experimental research has shown that the centromedian-parafascicular complex (CM-Pf) of the intralaminar thalamus is activated in attentional orienting and processing of behaviorally relevant stimuli. These observations resulted in the hypothesis that the CM-Pf plays a pivotal role in goal-oriented behavior selection. We here set out to test this hypothesis with electrophysiological recordings from patients with electrodes implanted in CM-Pf for deep brain stimulation (DBS) treatment of chronic neuropathic pain. Six patients participated in (1) an auditory three-class oddball experiment, which required a button press to target tones, but not to standard and deviant tones and in (2) a multi-speaker experiment with a target word that required attention selection and a target image that required response selection. Subjects showed transient neural responses (8-15Hz) to the target tone and the target word. Two subjects additionally showed transient neural responses (15-25Hz) to the target image. All sensory target stimuli were related to an internal goal and required a behavior selection (attention selection, response selection). In group analyses, neural responses were greater to target tones than deviant and standard tones and to target words than other task-relevant words that did not require attention selection. The transient neural responses occurred after the target stimuli but prior to the overt behavioral response. Our results demonstrate that in human subjects the CM-Pf is involved in signaling sensory inputs related to goal-oriented selection of behavior. Copyright © 2017 Elsevier Inc. All rights reserved.

Development and Antarctic Testing of a Maneuverable Probe for Clean In-Situ Analysis and Sampling of Subsurface Ice and Subglacial Aquatic Ecosystems

NASA Astrophysics Data System (ADS)

Francke, G.; Dachwald, B.; Kowalski, J.; Digel, I.; Tulaczyk, S. M.; Mikucki, J.; Feldmann, M.; Espe, C.; Schöngarth, S.; Hiecker, S.; Blandfort, D.; Schüller, K.; Plescher, E.

2016-12-01

There is significant interest in sampling subglacial environments for geochemical and microbiological studies, but those environments are difficult to access. Such environments exist not only on Earth but are also expected beneath the icy crusts of some outer solar system bodies, like the Jovian moon Europa and the Saturnian moon Enceladus. Existing ice drilling technologies make it cumbersome to maintain microbiologically clean access for sample acquisition and environmental stewardship of potentially fragile subglacial aquatic ecosystems. The "IceMole" is a maneuverable subsurface ice probe for clean in-situ analysis and sampling of glacial ice and subglacial materials. The design is based on combining melting and mechanical propulsion, using an ice screw at the tip of the melting head to maintain firm contact between the melting head and the ice. It can change melting direction by differential heating of the melting head and optional side wall heaters. The first two prototypes were successfully tested between 2010 and 2012 on glaciers in Switzerland and Iceland, where they demonstrated downward, horizontal and upward melting, as well as curve driving and dirt layer penetration. Hence, the IceMole allows maneuvers which may be necessary for obstacle avoidance or target selection. Maneuverability, however, necessitates a sophisticated on-board navigation system capable of autonomous operations. Therefore, between 2012 and 2014, a more advanced probe was developed as part of the "Enceladus Explorer" (EnEx) project. The EnEx-IceMole offers systems for relative positioning based on in-ice attitude determination, acoustic positioning, ultrasonic obstacle and target detection, which is all integrated through a high-level sensor fusion. In December 2014, it was used for clean access into a unique subglacial aquatic environment at Blood Falls, Antarctica, where a subglacial brine sample was successfully obtained after about 17 meters of oblique melting. Particular attention was paid to clean protocols for the sampling of subglacial materials for geochemical and microbiological analysis. Much more development has to be done in many areas, however, until the probe can be used for extraterrestrial applications.

Sensorimotor integration of vision and proprioception for obstacle crossing in ambulatory individuals with spinal cord injury.

PubMed

Malik, Raza Naseem; Cote, Rachel; Lam, Tania

2017-01-01

Skilled walking, such as obstacle crossing, is an essential component of functional mobility. Sensorimotor integration of visual and proprioceptive inputs is important for successful obstacle crossing. The objective of this study was to understand how proprioceptive deficits affect obstacle-crossing strategies when controlling for variations in motor deficits in ambulatory individuals with spinal cord injury (SCI). Fifteen ambulatory individuals with SCI and 15 able-bodied controls were asked to step over an obstacle scaled to their motor abilities under full and obstructed vision conditions. An eye tracker was used to determine gaze behaviour and motion capture analysis was used to determine toe kinematics relative to the obstacle. Combined, bilateral hip and knee proprioceptive sense (joint position sense and movement detection sense) was assessed using the Lokomat and customized software controls. Combined, bilateral hip and knee proprioceptive sense in subjects with SCI varied and was significantly different from able-bodied subjects. Subjects with greater proprioceptive deficits stepped higher over the obstacle with their lead and trail limbs in the obstructed vision condition compared with full vision. Subjects with SCI also glanced at the obstacle more frequently and with longer fixation times compared with controls, but this was not related to proprioceptive sense. This study indicates that ambulatory individuals with SCI rely more heavily on vision to cross obstacles and show impairments in key gait parameters required for successful obstacle crossing. Our data suggest that proprioceptive deficits need to be considered in rehabilitation programs aimed at improving functional mobility in ambulatory individuals with SCI. This work is unique since it examines the contribution of combined, bilateral hip and knee proprioceptive sense on the recovery of skilled walking function, in addition to characterizing gaze behavior during a skilled walking task in people with motor-incomplete spinal cord injury. Copyright © 2017 the American Physiological Society.

Incentives in financing mental health care in Austria.

PubMed

Zechmeister, Ingrid; Oesterle, August; Denk, Peter; Katschnig, Heinz

2002-09-01

In Austria, financing health care -and even more so mental health care- is characterized by a mix of federal and provincial responsibilities, lack of uniformity in service provision and service providers, and diverse funding arrangements. The division between financing structures for health care and social care makes the situation even more complex. This state of affairs results in various, partly counterproductive and sometimes paradoxical financial incentives and disincentives for the providers, recipients and financiers of mental health services. In several provinces of Austria, recent reform plans in mental health care have focused strongly on establishing community-based and patient-oriented mental health care. One of the main challenges in implementing this new policy is the re-allocation of resources. The authors hypothesize that the existing structure of mental health care financing, with its incentives and disincentives, constitutes an obstacle to patient-oriented community-based mental health care. Analyzing the characteristics of the overall mental health care financing system in one Austrian province, Lower Austria, will provide a better understanding of actor-relationships and inherent incentives and highlight implications for the process of deinstitutionalization. The authors used an analytical framework based on the principal-agent theory, empirical evidence, and information on financial, organizational and legal structures to identify the characteristics of actor-relationships and the position of single actors within the system. The article shows how incentives are linked to existing constellations of actors involved in mental health care financing and identifies significant power relations. As a consequence, incentives and disincentives within the financing system result in hospital- centered and supply-oriented mental health care in Lower Austria. The current system of financing mental health care provides an obstacle to the provision of patient-oriented and community-based mental care. This is due to existing constellations and power relations among the actors where, most importantly, patients are the weakest party in the patient-payer-provider triangle. Balancing power relations will be a significant prerequisite for alternative financing systems. IMPLICATIONS FOR HEALTH POLICIES AND FURTHER RESEARCH: If a community and needs-based mental health care system is to be established in Austria, the financing structures have to be changed accordingly. Applying a principal-agent framework is useful for identifying key aspects in mental health care financing in relation to the provision of services. Further research is needed to help develop alternative financing mechanisms that support community-based and patient-oriented mental health care systems.

Injury resulting from targeted violence: An emergency department perspective.

PubMed

Sivarajasingam, Vaseekaran; Read, Simon; Svobodova, Martina; Wight, Lucy; Shepherd, Jonathan

2018-06-01

Hate crimes - those perpetrated because of perceived difference, including disability, race, religion, sexual orientation or transgender status - have not been studied at the point of the victim's hospital emergency department (ED) use. To investigate the frequency, levels of physical harm and circumstances of targeted violence in those seeking treatment at EDs in three UK cities. In a multimethods study, face-to-face semi-structured interviews were conducted with 124 adult ED attenders with violent injuries. Victim and perpetrator socio-demographics were recorded. Patient narratives about perceived motives and circumstances were transcribed, uploaded onto NVivo for thematic analysis. Nearly a fifth (23, 18.5%) of the injured patients considered themselves to have been attacked by others motivated by hostility or prejudice to their 'difference' (targeted violence). Thematic analyses suggested these prejudices were to appearance (7 cases), racial tension (5 cases), territorial association (3 cases) and race, religious or sexual orientation (8 cases). According to victims, alcohol intoxication was particularly relevant in targeted violence (estimated reported frequency 90% and 56% for targeted and non-targeted violence, respectively). Our findings support a broader concept of hate victimisation and suggest that emergency room violence surveys could act as a community tension sensor and early warning system in this regard. Tackling alcohol misuse seems as important in this as in other forms of violence perpetration. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

A multiscale approach for the reconstruction of the fiber architecture of the human brain based on 3D-PLI

PubMed Central

Reckfort, Julia; Wiese, Hendrik; Pietrzyk, Uwe; Zilles, Karl; Amunts, Katrin; Axer, Markus

2015-01-01

Structural connectivity of the brain can be conceptionalized as a multiscale organization. The present study is built on 3D-Polarized Light Imaging (3D-PLI), a neuroimaging technique targeting the reconstruction of nerve fiber orientations and therefore contributing to the analysis of brain connectivity. Spatial orientations of the fibers are derived from birefringence measurements of unstained histological sections that are interpreted by means of a voxel-based analysis. This implies that a single fiber orientation vector is obtained for each voxel, which reflects the net effect of all comprised fibers. We have utilized two polarimetric setups providing an object space resolution of 1.3 μm/px (microscopic setup) and 64 μm/px (macroscopic setup) to carry out 3D-PLI and retrieve fiber orientations of the same tissue samples, but at complementary voxel sizes (i.e., scales). The present study identifies the main sources which cause a discrepancy of the measured fiber orientations observed when measuring the same sample with the two polarimetric systems. As such sources the differing optical resolutions and diverging retardances of the implemented waveplates were identified. A methodology was implemented that enables the compensation of measured different systems' responses to the same birefringent sample. This opens up new ways to conduct multiscale analysis in brains by means of 3D-PLI and to provide a reliable basis for the transition between different scales of the nerve fiber architecture. PMID:26388744

Supraliminal but not subliminal distracters bias working memory recall.

PubMed

Wildegger, Theresa; Myers, Nicholas E; Humphreys, Glyn; Nobre, Anna C

2015-06-01

Information of which observers are not consciously aware can nevertheless influence perceptual processes. Whether subliminal information might exert an influence on working memory (WM) representations is less clear, and relatively few studies have examined the interactions between subliminal and supraliminal information in WM. We present 3 experiments examining this issue. Experiments 1a and b replicated the finding that orientation stimuli can influence behavior subliminally in a visuomotor priming task. Experiments 2 and 3 used the same orientation stimuli, but participants had to remember a target orientation and report it back by adjusting a probe orientation after a memory delay. Before or after presentation of the target orientation, a subliminal or supraliminal distracter orientation was presented that was either irrelevant for task completion and never had to be reported (Experiment 2), or was relevant for task completion because it had to be reported on some trials (Experiment 3). In both experiments, presentation of a supraliminal distracter influenced WM recall of the target orientation. When the distracter was presented subliminally, however, there was no bias in orientation recall. These results suggest that information stored in WM is protected from influences of subliminal stimuli, while online information processing is modulated by subliminal information. (c) 2015 APA, all rights reserved).

Evaluation of Head Orientation and Neck Muscle EMG Signals as Command Inputs to a Human-Computer Interface for Individuals with High Tetraplegia

PubMed Central

Williams, Matthew R.; Kirsch, Robert F.

2013-01-01

We investigated the performance of three user interfaces for restoration of cursor control in individuals with tetraplegia: head orientation, EMG from face and neck muscles, and a standard computer mouse (for comparison). Subjects engaged in a 2D, center-out, Fitts’ Law style task and performance was evaluated using several measures. Overall, head orientation commanded motion resembled mouse commanded cursor motion (smooth, accurate movements to all targets), although with somewhat lower performance. EMG commanded movements exhibited a higher average speed, but other performance measures were lower, particularly for diagonal targets. Compared to head orientation, EMG as a cursor command source was less accurate, was more affected by target direction and was more prone to overshoot the target. In particular, EMG commands for diagonal targets were more sequential, moving first in one direction and then the other rather than moving simultaneous in the two directions. While the relative performance of each user interface differs, each has specific advantages depending on the application. PMID:18990652

A Nonlinear Model Predictive Control Algorithm for Obstacle Avoidance in Autonomous Ground Vehicles within Unknown Environments

DTIC Science & Technology

2015-04-24

xs , ys , xe , ye ) double EndPo in t s [L...Distribution Statement A. Approved for public release. #26161 350 400 450 100 150 200 250 300 350 400 450 500 550 600 x (m) y (m ) Start Target U0 = 10...longitudinal speed 350 400 450 100 150 200 250 300 350 400 450 500 550 600 x (m) y (m ) Start Target (a) Trajectory 0 5 10 15 0 1 t (s) f ( U0 = 30

A resource of potential drug targets and strategic decision-making for obstructive sleep apnoea pharmacotherapy.

PubMed

Horner, Richard L; Grace, Kevin P; Wellman, Andrew

2017-07-01

There is currently no pharmacotherapy for obstructive sleep apnoea (OSA) but there is no principled a priori reason why there should not be one. This review identifies a rational decision-making strategy with the necessary logical underpinnings that any reasonable approach would be expected to navigate to develop a viable pharmacotherapy for OSA. The process first involves phenotyping an individual to quantify and characterize the critical predisposing factor(s) to their OSA pathogenesis and identify, a priori, if the patient is likely to benefit from a pharmacotherapy that targets those factors. We then identify rational strategies to manipulate those critical predisposing factor(s), and the barriers that have to be overcome for success of any OSA pharmacotherapy. A new analysis then identifies candidate drug targets to manipulate the upper airway motor circuitry for OSA pharmacotherapy. The first conclusion is that there are two general pharmacological approaches for OSA treatment that are of the most potential benefit and are practically realistic, one being fairly intuitive but the second perhaps less so. The second conclusion is that after identifying the critical physiological obstacles to OSA pharmacotherapy, there are current therapeutic targets of high interest for future development. The final analysis provides a tabulated resource of 'druggable' targets that are relatively restricted to the circuitry controlling the upper airway musculature, with these candidate targets being of high priority for screening and further study. We also emphasize that a pharmacotherapy may not cure OSA per se, but may still be a useful adjunct to improve the effectiveness of, and adherence to, other treatment mainstays. © 2017 The Authors. Respirology published by John Wiley & Sons Australia, Ltd on behalf of Asian Pacific Society of Respirology.

A new multi-spectral feature level image fusion method for human interpretation

NASA Astrophysics Data System (ADS)

Leviner, Marom; Maltz, Masha

2009-03-01

Various different methods to perform multi-spectral image fusion have been suggested, mostly on the pixel level. However, the jury is still out on the benefits of a fused image compared to its source images. We present here a new multi-spectral image fusion method, multi-spectral segmentation fusion (MSSF), which uses a feature level processing paradigm. To test our method, we compared human observer performance in a three-task experiment using MSSF against two established methods: averaging and principle components analysis (PCA), and against its two source bands, visible and infrared. The three tasks that we studied were: (1) simple target detection, (2) spatial orientation, and (3) camouflaged target detection. MSSF proved superior to the other fusion methods in all three tests; MSSF also outperformed the source images in the spatial orientation and camouflaged target detection tasks. Based on these findings, current speculation about the circumstances in which multi-spectral image fusion in general and specific fusion methods in particular would be superior to using the original image sources can be further addressed.

Task relevance modulates the cortical representation of feature conjunctions in the target template.

PubMed

Reeder, Reshanne R; Hanke, Michael; Pollmann, Stefan

2017-07-03

Little is known about the cortical regions involved in representing task-related content in preparation for visual task performance. Here we used representational similarity analysis (RSA) to investigate the BOLD response pattern similarity between task relevant and task irrelevant feature dimensions during conjunction viewing and target template maintenance prior to visual search. Subjects were cued to search for a spatial frequency (SF) or orientation of a Gabor grating and we measured BOLD signal during cue and delay periods before the onset of a search display. RSA of delay period activity revealed that widespread regions in frontal, posterior parietal, and occipitotemporal cortices showed general representational differences between task relevant and task irrelevant dimensions (e.g., orientation vs. SF). In contrast, RSA of cue period activity revealed sensory-related representational differences between cue images (regardless of task) at the occipital pole and additionally in the frontal pole. Our data show that task and sensory information are represented differently during viewing and during target template maintenance, and that task relevance modulates the representation of visual information across the cortex.

Comparative Analysis of the Molecular Adjuvants and Their Binding Efficiency with CR1.

PubMed

Saranya, B; Saxena, Shweta; Saravanan, K M; Shakila, H

2016-03-01

There are so many obstacles in developing a vaccine or vaccine technology for diseases like cancer and human immunodeficiency virus infection. While developing vaccines that target specific infection, molecular adjuvants are indispensable. These molecular adjuvants act as a vaccine delivery vehicle to the immune system to increase the effectiveness of the specific antigens. In the present work, a computational study has been done on molecular adjuvants like IgGFc, GMCSF and C3d to find out how efficiently they are binding to CR1. Sequence, structure and mutational analysis are performed on the molecular adjuvants to understand the features important for their binding with the receptor. Results obtained from our study indicate that the adjuvant IgGFc complexed with the receptor CR1 has the best binding efficiency, which can be used further to develop better vaccine technologies.

Differential white matter involvement associated with distinct visuospatial deficits after right hemisphere stroke.

PubMed

Carter, Alex R; McAvoy, Mark P; Siegel, Joshua S; Hong, Xin; Astafiev, Serguei V; Rengachary, Jennifer; Zinn, Kristi; Metcalf, Nicholas V; Shulman, Gordon L; Corbetta, Maurizio

2017-03-01

Visuospatial attention depends on the integration of multiple processes, and people with right hemisphere lesions after a stroke may exhibit severe or no visuospatial deficits. The anatomy of core components of visuospatial attention is an area of intense interest. Here we examine the relationship between the disruption of core components of attention and lesion distribution in a heterogeneous group (N = 70) of patients with right hemisphere strokes regardless of the presence of clinical neglect. Deficits of lateralized spatial orienting, measured as the difference in reaction times for responding to visual targets in the contralesional or ipsilesional visual field, and deficits in re-orienting attention, as measured by the difference in reaction times for invalidly versus validly cued targets, were measured using a computerized spatial orienting task. Both measures were related through logistic regression and a novel ridge regression method to anatomical damage measured with magnetic resonance imaging. While many regions were common to both deficit maps, a deficit in lateralized spatial orienting was more associated with lesions in the white matter underlying the posterior parietal cortex, and middle and inferior frontal gyri. A deficit in re-orienting of attention toward unattended locations was associated with lesions in the white matter of the posterior parietal cortex, insular cortex and less so with white matter involvement of the anterior frontal lobe. An hodological analysis also supports this partial dissociation between the white matter tracts that are damaged in lateralized spatial biases versus impaired re-orienting. Our results underscore that the integrity of fronto-parietal white matter tracts is crucial for visuospatial attention and that different attention components are mediated by partially distinct neuronal substrates. Copyright © 2016 Elsevier Ltd. All rights reserved.

High-Frequency Replanning Under Uncertainty Using Parallel Sampling-Based Motion Planning

PubMed Central

Sun, Wen; Patil, Sachin; Alterovitz, Ron

2015-01-01

As sampling-based motion planners become faster, they can be re-executed more frequently by a robot during task execution to react to uncertainty in robot motion, obstacle motion, sensing noise, and uncertainty in the robot’s kinematic model. We investigate and analyze high-frequency replanning (HFR), where, during each period, fast sampling-based motion planners are executed in parallel as the robot simultaneously executes the first action of the best motion plan from the previous period. We consider discrete-time systems with stochastic nonlinear (but linearizable) dynamics and observation models with noise drawn from zero mean Gaussian distributions. The objective is to maximize the probability of success (i.e., avoid collision with obstacles and reach the goal) or to minimize path length subject to a lower bound on the probability of success. We show that, as parallel computation power increases, HFR offers asymptotic optimality for these objectives during each period for goal-oriented problems. We then demonstrate the effectiveness of HFR for holonomic and nonholonomic robots including car-like vehicles and steerable medical needles. PMID:26279645

Application of a three-feature dispersed-barrier hardening model to neutron-irradiated Fe-Cr model alloys

NASA Astrophysics Data System (ADS)

Bergner, F.; Pareige, C.; Hernández-Mayoral, M.; Malerba, L.; Heintze, C.

2014-05-01

An attempt is made to quantify the contributions of different types of defect-solute clusters to the total irradiation-induced yield stress increase in neutron-irradiated (300 °C, 0.6 dpa), industrial-purity Fe-Cr model alloys (target Cr contents of 2.5, 5, 9 and 12 at.% Cr). Former work based on the application of transmission electron microscopy, atom probe tomography, and small-angle neutron scattering revealed the formation of dislocation loops, NiSiPCr-enriched clusters and α‧-phase particles, which act as obstacles to dislocation glide. The values of the dimensionless obstacle strength are estimated in the framework of a three-feature dispersed-barrier hardening model. Special attention is paid to the effect of measuring errors, experimental details and model details on the estimates. The three families of obstacles and the hardening model are well capable of reproducing the observed yield stress increase as a function of Cr content, suggesting that the nanostructural features identified experimentally are the main, if not the only, causes of irradiation hardening in these model alloys.

Stereo vision tracking of multiple objects in complex indoor environments.

PubMed

Marrón-Romera, Marta; García, Juan C; Sotelo, Miguel A; Pizarro, Daniel; Mazo, Manuel; Cañas, José M; Losada, Cristina; Marcos, Alvaro

2010-01-01

This paper presents a novel system capable of solving the problem of tracking multiple targets in a crowded, complex and dynamic indoor environment, like those typical of mobile robot applications. The proposed solution is based on a stereo vision set in the acquisition step and a probabilistic algorithm in the obstacles position estimation process. The system obtains 3D position and speed information related to each object in the robot's environment; then it achieves a classification between building elements (ceiling, walls, columns and so on) and the rest of items in robot surroundings. All objects in robot surroundings, both dynamic and static, are considered to be obstacles but the structure of the environment itself. A combination of a Bayesian algorithm and a deterministic clustering process is used in order to obtain a multimodal representation of speed and position of detected obstacles. Performance of the final system has been tested against state of the art proposals; test results validate the authors' proposal. The designed algorithms and procedures provide a solution to those applications where similar multimodal data structures are found.

The application of Markov decision process in restaurant delivery robot

NASA Astrophysics Data System (ADS)

Wang, Yong; Hu, Zhen; Wang, Ying

2017-05-01

As the restaurant delivery robot is often in a dynamic and complex environment, including the chairs inadvertently moved to the channel and customers coming and going. The traditional path planning algorithm is not very ideal. To solve this problem, this paper proposes the Markov dynamic state immediate reward (MDR) path planning algorithm according to the traditional Markov decision process. First of all, it uses MDR to plan a global path, then navigates along this path. When the sensor detects there is no obstructions in front state, increase its immediate state reward value; when the sensor detects there is an obstacle in front, plan a global path that can avoid obstacle with the current position as the new starting point and reduce its state immediate reward value. This continues until the target is reached. When the robot learns for a period of time, it can avoid those places where obstacles are often present when planning the path. By analyzing the simulation experiment, the algorithm has achieved good results in the global path planning under the dynamic environment.

The effects of platform motion and target orientation on the performance of trackball manipulation.

PubMed

Yau, Yi-Jan; Chao, Chin-Jung; Feng, Wen-Yang; Hwang, Sheue-Ling

2011-08-01

The trackball has been widely employed as a control/command input device on moving vehicles, but few studies have explored the effects of platform motion on its manipulation. Fewer still have considered this issue in designing the user interface and the arrangement of console location and orientation simultaneously. This work describes an experiment carried out to investigate the performance of trackball users on a simple point-and-click task in a motion simulator. By varying the orientation of onscreen targets, the effect of cursor movement direction on performance is investigated. The results indicate that the platform motion and target orientation both significantly affect the time required to point and click, but not the accuracy of target selection. The movement times were considerably longer under rolling and pitching motions and for targets located along the diagonal axes of the interface. Subjective evaluations carried out by the participants agree with these objective results. These findings could be used to optimise console and graphical menu design for use on maritime vessels. STATEMENT OF RELEVANCE: In military situations, matters of life or death may be decided in milliseconds. Any delay or error in classification and identification will thus affect the safety of the ship and its crew. This study demonstrates that performance of manipulating a trackball is affected by the platform motion and target orientation. The results of the present study can guide the arrangement of consoles and the design of trackball-based graphical user interfaces on maritime vessels.

Transgender Voice and Communication Treatment: A Retrospective Chart Review of 25 Cases

ERIC Educational Resources Information Center

Hancock, Adrienne B.; Garabedian, Laura M.

2013-01-01

Background: People transitioning from male to female (MTF) gender seek speech-language pathology services when they feel their voice is betraying their genuine self or perhaps is the last obstacle to representing their authentic gender. Speaking fundamental frequency (pitch) and resonance are most often targets in treatment because the combination…

Hopes & Hurdles: California Foster Youth and College Financial Aid

ERIC Educational Resources Information Center

Cochrane, Deborah Frankle; Szabo-Kubitz, Laura

2009-01-01

This report examines why former foster youth in California are not receiving the aid they are likely eligible for, from inadequate or poorly targeted information about college costs and financial aid to structural obstacles within the aid process and programs. While many of this report's findings and recommendations are specific to foster youth,…

Targeted enrichment strategies for next-generation plant biology

Treesearch

Richard Cronn; Brian J. Knaus; Aaron Liston; Peter J. Maughan; Matthew Parks; John V. Syring; Joshua Udall

2012-01-01

The dramatic advances offered by modem DNA sequencers continue to redefine the limits of what can be accomplished in comparative plant biology. Even with recent achievements, however, plant genomes present obstacles that can make it difficult to execute large-scale population and phylogenetic studies on next-generation sequencing platforms. Factors like large genome...

Classroom Silence: Voices from Japanese EFL Learners

ERIC Educational Resources Information Center

Harumi, Seiko

2011-01-01

This article explores Japanese EFL learners' classroom silence in a Japanese EFL context. The existence of silence in second language learning contexts can be a source of conflict between students and teachers and even among students themselves. It can also be an obstacle to acquiring the target language. In order to tackle this problem and to…

An algorithm for automatic target recognition using passive radar and an EKF for estimating aircraft orientation

NASA Astrophysics Data System (ADS)

Ehrman, Lisa M.

2005-07-01

Rather than emitting pulses, passive radar systems rely on "illuminators of opportunity," such as TV and FM radio, to illuminate potential targets. These systems are attractive since they allow receivers to operate without emitting energy, rendering them covert. Until recently, most of the research regarding passive radar has focused on detecting and tracking targets. This dissertation focuses on extending the capabilities of passive radar systems to include automatic target recognition. The target recognition algorithm described in this dissertation uses the radar cross section (RCS) of potential targets, collected over a short period of time, as the key information for target recognition. To make the simulated RCS as accurate as possible, the received signal model accounts for aircraft position and orientation, propagation losses, and antenna gain patterns. An extended Kalman filter (EKF) estimates the target's orientation (and uncertainty in the estimate) from velocity measurements obtained from the passive radar tracker. Coupling the aircraft orientation and state with the known antenna locations permits computation of the incident and observed azimuth and elevation angles. The Fast Illinois Solver Code (FISC) simulates the RCS of potential target classes as a function of these angles. Thus, the approximated incident and observed angles allow the appropriate RCS to be extracted from a database of FISC results. Using this process, the RCS of each aircraft in the target class is simulated as though each is executing the same maneuver as the target detected by the system. Two additional scaling processes are required to transform the RCS into a power profile (magnitude only) simulating the signal in the receiver. First, the RCS is scaled by the Advanced Refractive Effects Prediction System (AREPS) code to account for propagation losses that occur as functions of altitude and range. Then, the Numerical Electromagnetic Code (NEC2) computes the antenna gain pattern, further scaling the RCS. A Rician likelihood model compares the scaled RCS of the illuminated aircraft with those of the potential targets. To improve the robustness of the result, the algorithm jointly optimizes over feasible orientation profiles and target types via dynamic programming.

Technology test results from an intelligent, free-flying robot for crew and equipment retrieval in space

NASA Technical Reports Server (NTRS)

Erickson, J.; Goode, R.; Grimm, K.; Hess, C.; Norsworthy, R.; Anderson, G.; Merkel, L.; Phinney, D.

1992-01-01

The ground-based demonstrations of Extra Vehicular Activity (EVA) Retriever, a voice-supervised, intelligent, free-flying robot, are designed to evaluate the capability to retrieve objects (astronauts, equipment, and tools) which have accidentally separated from the Space Station. The EVA Retriever software is required to autonomously plan and execute a target rendezvous, grapple, and return to base while avoiding stationary and moving obstacles with subsequent object handover. The software architecture incorporates a heirarchical decomposition of the control system that is horizontally partitioned into five major functional subsystems: sensing, perception, world model, reasoning, and acting. The design provides for supervised autonomy as the primary mode of operation. It is intended to be an evolutionary system improving in capability over time and as it earns crew trust through reliable and safe operation. This paper gives an overview of the hardware, a focus on software, and a summary of results achieved recently from both computer simulations and air bearing floor demonstrations. Limitations of the technology used are evaluated. Plans for the next phase, during which moving targets and obstacles drive realtime behavior requirements, are discussed.

Technology test results from an intelligent, free-flying robot for crew and equipment retrieval in space

NASA Astrophysics Data System (ADS)

Erickson, Jon D.; Goode, R.; Grimm, K. A.; Hess, Clifford W.; Norsworthy, Robert S.; Anderson, Greg D.; Merkel, L.; Phinney, Dale E.

1992-03-01

The ground-based demonstrations of Extra Vehicular Activity (EVA) Retriever, a voice- supervised, intelligent, free-flying robot, are designed to evaluate the capability to retrieve objects (astronauts, equipment, and tools) which have accidentally separated from the space station. The EVA Retriever software is required to autonomously plan and execute a target rendezvous, grapple, and return to base while avoiding stationary and moving obstacles with subsequent object handover. The software architecture incorporates a hierarchical decomposition of the control system that is horizontally partitioned into five major functional subsystems: sensing, perception, world model, reasoning, and acting. The design provides for supervised autonomy as the primary mode of operation. It is intended to be an evolutionary system improving in capability over time and as it earns crew trust through reliable and safe operation. This paper gives an overview of the hardware, a focus on software, and a summary of results achieved recently from both computer simulations and air bearing floor demonstrations. Limitations of the technology used are evaluated. Plans for the next phase, during which moving targets and obstacles drive realtime behavior requirements, are discussed.

Hopping Robot with Wheels

NASA Technical Reports Server (NTRS)

Barlow, Edward; Marzwell, Nevellie; Fuller, Sawyer; Fionni, Paolo; Tretton, Andy; Burdick, Joel; Schell, Steve

2003-01-01

A small prototype mobile robot is capable of (1) hopping to move rapidly or avoid obstacles and then (2) moving relatively slowly and precisely on the ground by use of wheels in the manner of previously reported exploratory robots of the "rover" type. This robot is a descendant of a more primitive hopping robot described in "Minimally Actuated Hopping Robot" (NPO- 20911), NASA Tech Briefs, Vol. 26, No. 11 (November 2002), page 50. There are many potential applications for robots with hopping and wheeled-locomotion (roving) capabilities in diverse fields of endeavor, including agriculture, search-and-rescue operations, general military operations, removal or safe detonation of land mines, inspection, law enforcement, and scientific exploration on Earth and remote planets. The combination of hopping and roving enables this robot to move rapidly over very rugged terrain, to overcome obstacles several times its height, and then to position itself precisely next to a desired target. Before a long hop, the robot aims itself in the desired hopping azimuth and at a desired takeoff angle above horizontal. The robot approaches the target through a series of hops and short driving operations utilizing the steering wheels for precise positioning.

Object tracking algorithm based on the color histogram probability distribution

NASA Astrophysics Data System (ADS)

Li, Ning; Lu, Tongwei; Zhang, Yanduo

2018-04-01

In order to resolve tracking failure resulted from target's being occlusion and follower jamming caused by objects similar to target in the background, reduce the influence of light intensity. This paper change HSV and YCbCr color channel correction the update center of the target, continuously updated image threshold self-adaptive target detection effect, Clustering the initial obstacles is roughly range, shorten the threshold range, maximum to detect the target. In order to improve the accuracy of detector, this paper increased the Kalman filter to estimate the target state area. The direction predictor based on the Markov model is added to realize the target state estimation under the condition of background color interference and enhance the ability of the detector to identify similar objects. The experimental results show that the improved algorithm more accurate and faster speed of processing.

The didactic situation in geometry learning based on analysis of learning obstacles and learning trajectory

NASA Astrophysics Data System (ADS)

Sulistyowati, Fitria; Budiyono, Slamet, Isnandar

2017-12-01

This study aims to design a didactic situation based on the analysis of learning obstacles and learning trajectory on prism volume. The type of this research is qualitative and quantitative research with steps: analyzing the learning obstacles and learning trajectory, preparing the didactic situation, applying the didactic situation in the classroom, mean difference test of problem solving ability with t-test statistic. The subjects of the study were 8th grade junior high school students in Magelang 2016/2017 selected randomly from eight existing classes. The result of this research is the design of didactic situations that can be implemented in prism volume learning. The effectiveness of didactic situations that have been designed is shown by the mean difference test that is the problem solving ability of the students after the application of the didactic situation better than before the application. The didactic situation that has been generated is expected to be a consideration for teachers to design lessons that match the character of learners, classrooms and teachers themselves, so that the potential thinking of learners can be optimized to avoid the accumulation of learning obstacles.

Modal element method for potential flow in non-uniform ducts: Combining closed form analysis with CFD

NASA Technical Reports Server (NTRS)

Baumeister, Kenneth J.; Baumeister, Joseph F.

1994-01-01

An analytical procedure is presented, called the modal element method, that combines numerical grid based algorithms with eigenfunction expansions developed by separation of variables. A modal element method is presented for solving potential flow in a channel with two-dimensional cylindrical like obstacles. The infinite computational region is divided into three subdomains; the bounded finite element domain, which is characterized by the cylindrical obstacle and the surrounding unbounded uniform channel entrance and exit domains. The velocity potential is represented approximately in the grid based domain by a finite element solution and is represented analytically by an eigenfunction expansion in the uniform semi-infinite entrance and exit domains. The calculated flow fields are in excellent agreement with exact analytical solutions. By eliminating the grid surrounding the obstacle, the modal element method reduces the numerical grid size, employs a more precise far field boundary condition, as well as giving theoretical insight to the interaction of the obstacle with the mean flow. Although the analysis focuses on a specific geometry, the formulation is general and can be applied to a variety of problems as seen by a comparison to companion theories in aeroacoustics and electromagnetics.

Perceptual Learning Selectively Refines Orientation Representations in Early Visual Cortex

PubMed Central

Jehee, Janneke F.M.; Ling, Sam; Swisher, Jascha D.; van Bergen, Ruben S.; Tong, Frank

2013-01-01

Although practice has long been known to improve perceptual performance, the neural basis of this improvement in humans remains unclear. Using fMRI in conjunction with a novel signal detection-based analysis, we show that extensive practice selectively enhances the neural representation of trained orientations in the human visual cortex. Twelve observers practiced discriminating small changes in the orientation of a laterally presented grating over 20 or more daily one-hour training sessions. Training on average led to a two-fold improvement in discrimination sensitivity, specific to the trained orientation and the trained location, with minimal improvement found for untrained orthogonal orientations or for orientations presented in the untrained hemifield. We measured the strength of orientation-selective responses in individual voxels in early visual areas (V1–V4) using signal detection measures, both pre- and post-training. Although the overall amplitude of the BOLD response was no greater after training, practice nonetheless specifically enhanced the neural representation of the trained orientation at the trained location. This training-specific enhancement of orientation-selective responses was observed in the primary visual cortex (V1) as well as higher extrastriate visual areas V2–V4, and moreover, reliably predicted individual differences in the behavioral effects of perceptual learning. These results demonstrate that extensive training can lead to targeted functional reorganization of the human visual cortex, refining the cortical representation of behaviorally relevant information. PMID:23175828

Perceptual learning selectively refines orientation representations in early visual cortex.

PubMed

Jehee, Janneke F M; Ling, Sam; Swisher, Jascha D; van Bergen, Ruben S; Tong, Frank

2012-11-21

Although practice has long been known to improve perceptual performance, the neural basis of this improvement in humans remains unclear. Using fMRI in conjunction with a novel signal detection-based analysis, we show that extensive practice selectively enhances the neural representation of trained orientations in the human visual cortex. Twelve observers practiced discriminating small changes in the orientation of a laterally presented grating over 20 or more daily 1 h training sessions. Training on average led to a twofold improvement in discrimination sensitivity, specific to the trained orientation and the trained location, with minimal improvement found for untrained orthogonal orientations or for orientations presented in the untrained hemifield. We measured the strength of orientation-selective responses in individual voxels in early visual areas (V1-V4) using signal detection measures, both before and after training. Although the overall amplitude of the BOLD response was no greater after training, practice nonetheless specifically enhanced the neural representation of the trained orientation at the trained location. This training-specific enhancement of orientation-selective responses was observed in the primary visual cortex (V1) as well as higher extrastriate visual areas V2-V4, and moreover, reliably predicted individual differences in the behavioral effects of perceptual learning. These results demonstrate that extensive training can lead to targeted functional reorganization of the human visual cortex, refining the cortical representation of behaviorally relevant information.

Political Obstacles to Regionalization of the SUS: perceptions of Municipal Health Secretaries with seat in the Bipartite Interagency Commissions.

PubMed

Moreira, Marcelo Rasga; Ribeiro, José Mendes; Ouverney, Assis Mafort

2017-04-01

This paper aims to identify and analyze the political obstacles to the implementation of Organizational Contract of Public Action (COAP) based on the perceptions of municipal health secretaries of Bipartite Interagency Commissions (CIB). For this purpose, we interviewed 195 secretaries (92% of the total) from October 2015 to August 2016. Based on the approach of policy analysis, the main hurdles identified were, in short, a traditional obstacle (lack of resources), one that has been gaining strength in recent years (judicialization of politics) and another, perhaps unheard of: the party-political system and the State Executive Branch are the great absentees in the coalitions in support of SUS regionalization policies. We can conclude that such obstacles indicate an extremely negative setting for the implementation of the COAP and other SUS regionalization policies. Thus, it is incumbent upon those involved to reflect, negotiate and build consensus on improving the health of the population and overcome such obstacles if, of course, they embrace the authors' concept that regionalization is fundamental for the SUS.

The contribution of forward masking to saccadic inhibition of return.

PubMed

Souto, David; Born, Sabine; Kerzel, Dirk

2018-03-08

Inhibition of return is the name typically given to the prolonged latency of motor responses directed to a previously cued target location. There is intense debate about the origins of this effect and its function, but most take for granted (despite lack of evidence) that it depends little on forward masking. Therefore, we re-examined the role of forward masking in inhibition of return. Forward masking was indexed by slower saccadic reaction times (SRTs) when the target orientation repeated the cue orientation at the same location. We confirmed effects of orientation repetition in the absence of an attentional bias when cues were presented on both sides of fixation (bilateral presentation). The effect of orientation repetition was reduced with high target contrast, consistent with a low-level origin such as contrast gain control in early visual areas. When presenting cues on only one side of fixation (unilateral presentation), we obtained inhibition of return with longer cue-target intervals and facilitation with targets presented shortly after the cue. The effect of orientation repetition was reduced when facilitation was observed, but was as strong as with bilateral cues when inhibition of return was observed. Therefore, forward masking may contribute to the inhibition of return effect by delaying reaction times to repeated features at the same location, but is not a principal cause of inhibition of return; in agreement with previous views. The saccadic inhibition of return effect is a reaction-time cost when responding to a pre-cued location. Additional object updating costs are typically invoked to explain reaction-time costs observed when cue and target have the same shape. Yet, lower-level, forward masking of the target by the cue can not be ruled out. Importantly, we show an effect of orientation repetition that is consistent with low-level forward masking rather than object updating costs and that does not interact with inhibition of return.

Reliable in their failure: an analysis of healthcare reform policies in public systems.

PubMed

Contandriopoulos, Damien; Brousselle, Astrid

2010-05-01

In this paper, we analyze recommendations of past governmental commissions and their implementation in Quebec as a case to discuss the obstacles that litter the road to healthcare system reform. Our analysis shows that the obstacles to tackling the healthcare system's main problems may have less to do with programmatic (what to do) than with political and governance (how to do it) questions. We then draw on neo-institutional theory to discuss the causes and effects of this situation. Copyright (c) 2009 Elsevier Ireland Ltd. All rights reserved.

Obstacles to nutrition labeling in restaurants.

PubMed

Almanza, B A; Nelson, D; Chai, S

1997-02-01

This study determined the major obstacles that foodservices face regarding nutrition labeling. Survey questionnaire was conducted in May 1994. In addition to demographic questions, the directors were asked questions addressing willingness, current practices, and perceived obstacles related to nutrition labeling. Sixty-eight research and development directors of the largest foodservice corporations as shown in Restaurants & Institutions magazine's list of the top 400 largest foodservices (July 1993). P tests were used to determine significance within a group for the number of foodservices that were currently using nutrition labeling, perceived impact of nutrition labeling on sales, and perceived responsibility to add nutrition labels. Regression analysis was used to determine the importance of factors on willingness to label. Response rate was 45.3%. Most companies were neutral about their willingness to use nutrition labeling. Two thirds of the respondents were not currently using nutrition labels. Only one third thought that it was the foodservice's responsibility to provide such information. Several companies perceived that nutrition labeling would have a potentially negative effect on annual sales volume. Major obstacles were identified as menu or personnel related, rather than cost related. Menu-related obstacles included too many menu variations, limited space on the menu for labeling, and loss of flexibility in changing the menu. Personnel-related obstacles included difficulty in training employees to implement nutrition labeling, and not enough time for foodservice personnel to implement nutrition labeling. Numerous opportunities will be created for dietetics professionals in helping foodservices overcome these menu- or personnel-related obstacles.

Urban-area extraction from polarimetric SAR image using combination of target decomposition and orientation angle

NASA Astrophysics Data System (ADS)

Zou, Bin; Lu, Da; Wu, Zhilu; Qiao, Zhijun G.

2016-05-01

The results of model-based target decomposition are the main features used to discriminate urban and non-urban area in polarimetric synthetic aperture radar (PolSAR) application. Traditional urban-area extraction methods based on modelbased target decomposition usually misclassified ground-trunk structure as urban-area or misclassified rotated urbanarea as forest. This paper introduces another feature named orientation angle to improve urban-area extraction scheme for the accurate mapping in urban by PolSAR image. The proposed method takes randomness of orientation angle into account for restriction of urban area first and, subsequently, implements rotation angle to improve results that oriented urban areas are recognized as double-bounce objects from volume scattering. ESAR L-band PolSAR data of the Oberpfaffenhofen Test Site Area was used to validate the proposed algorithm.

Establishing the Concepts and Techniques of Performance-Oriented Training in Army Training Centers: A Summary Report

DTIC Science & Technology

1975-06-01

techniques developed at Polk were later adopted by the other ATCs. As part of TRADOC’s effort to reorient the NCO Academy and Drill Sergeant * k .4chool...16D proceeded more smoothly than that fAr MOS 16E. The major obstacle to progress seems to have been la,’ k of a full appreciation oi the role and...These reviews also served to mreine the- t~ k lists further. The results of these reviews were presentod in two llumitR() con~iult’!i.’ reports.’ The

Reflexive Orienting in Response to Short- and Long-Duration Gaze Cues in Young, Young-Old, and Old-Old Adults

PubMed Central

Gayzur, Nora D.; Langley, Linda K.; Kelland, Chris; Wyman, Sara V.; Saville, Alyson L.; Ciernia, Annie T.; Padmanabhan, Ganesh

2013-01-01

Shifting visual focus based on the perceived gaze direction of another person is one form of joint attention. The present study investigated if this socially-relevant form of orienting is reflexive and whether it is influenced by age. Green and Woldorff (2012) argued that rapid cueing effects (faster responses to validly-cued targets than to invalidly-cued targets) were limited to conditions in which a cue overlapped in time with a target. They attributed slower responses following invalid cues to the time needed to resolve incongruent spatial information provided by the concurrently-presented cue and target. The present study examined orienting responses of young (18-31 years), young-old (60-74 years), and old-old adults (75-91 years) following uninformative central gaze cues that overlapped in time with the target (Experiment 1) or that were removed prior to target presentation (Experiment 2). When the cue and target overlapped, all three groups localized validly-cued targets faster than invalidly-cued targets, and validity effects emerged earlier for the two younger groups (at 100 ms post cue onset) than for the old-old group (at 300 ms post cue onset). With a short duration cue (Experiment 2), validity effects developed rapidly (by 100 ms) for all three groups, suggesting that validity effects resulted from reflexive orienting based on gaze cue information rather than from cue-target conflict. Thus, although old-old adults may be slow to disengage from persistent gaze cues, attention continues to be reflexively guided by gaze cues late in life. PMID:24170377

Analysis of Free Modeling Predictions by RBO Aleph in CASP11

PubMed Central

Mabrouk, Mahmoud; Werner, Tim; Schneider, Michael; Putz, Ines; Brock, Oliver

2015-01-01

The CASP experiment is a biannual benchmark for assessing protein structure prediction methods. In CASP11, RBO Aleph ranked as one of the top-performing automated servers in the free modeling category. This category consists of targets for which structural templates are not easily retrievable. We analyze the performance of RBO Aleph and show that its success in CASP was a result of its ab initio structure prediction protocol. A detailed analysis of this protocol demonstrates that two components unique to our method greatly contributed to prediction quality: residue–residue contact prediction by EPC-map and contact–guided conformational space search by model-based search (MBS). Interestingly, our analysis also points to a possible fundamental problem in evaluating the performance of protein structure prediction methods: Improvements in components of the method do not necessarily lead to improvements of the entire method. This points to the fact that these components interact in ways that are poorly understood. This problem, if indeed true, represents a significant obstacle to community-wide progress. PMID:26492194

Not all attention orienting is created equal: recognition memory is enhanced when attention orienting involves distractor suppression.

PubMed

Markant, Julie; Worden, Michael S; Amso, Dima

2015-04-01

Learning through visual exploration often requires orienting of attention to meaningful information in a cluttered world. Previous work has shown that attention modulates visual cortex activity, with enhanced activity for attended targets and suppressed activity for competing inputs, thus enhancing the visual experience. Here we examined the idea that learning may be engaged differentially with variations in attention orienting mechanisms that drive eye movements during visual search and exploration. We hypothesized that attention orienting mechanisms that engaged suppression of a previously attended location would boost memory encoding of the currently attended target objects to a greater extent than those that involve target enhancement alone. To test this hypothesis we capitalized on the classic spatial cueing task and the inhibition of return (IOR) mechanism (Posner, 1980; Posner, Rafal, & Choate, 1985) to demonstrate that object images encoded in the context of concurrent suppression at a previously attended location were encoded more effectively and remembered better than those encoded without concurrent suppression. Furthermore, fMRI analyses revealed that this memory benefit was driven by attention modulation of visual cortex activity, as increased suppression of the previously attended location in visual cortex during target object encoding predicted better subsequent recognition memory performance. These results suggest that not all attention orienting impacts learning and memory equally. Copyright © 2015 Elsevier Inc. All rights reserved.

Effects of coil orientation on the electric field induced by TMS over the hand motor area

NASA Astrophysics Data System (ADS)

Laakso, Ilkka; Hirata, Akimasa; Ugawa, Yoshikazu

2014-01-01

Responses elicited by transcranial magnetic stimulation (TMS) over the hand motor area depend on the position and orientation of the stimulating coil. In this work, we computationally investigate the induced electric field for multiple coil orientations and locations in order to determine which parts of the brain are affected and how the sensitivity of motor cortical activation depends on the direction of the electric field. The finite element method is used for calculating the electric field induced by TMS in two individual anatomical models of the head and brain. The orientation of the coil affects both the strength and depth of penetration of the electric field, and the field strongly depends on the direction of the sulcus, where the target neurons are located. The coil position that gives the strongest electric field in the target cortical region may deviate from the closest scalp location by a distance on the order of 1 cm. Together with previous experimental data, the results support the hypothesis that the cortex is most sensitive to fields oriented perpendicular to the cortical layers, while it is relatively insensitive to fields parallel to them. This has important implications for targeting of TMS. To determine the most effective coil position and orientation, it is essential to consider both biological (the direction of the targeted axons) and physical factors (the strength and direction of the electric field).

Detection of obstacles on runway using Ego-Motion compensation and tracking of significant features

NASA Technical Reports Server (NTRS)

Kasturi, Rangachar (Principal Investigator); Camps, Octavia (Principal Investigator); Gandhi, Tarak; Devadiga, Sadashiva

1996-01-01

This report describes a method for obstacle detection on a runway for autonomous navigation and landing of an aircraft. Detection is done in the presence of extraneous features such as tiremarks. Suitable features are extracted from the image and warping using approximately known camera and plane parameters is performed in order to compensate ego-motion as far as possible. Residual disparity after warping is estimated using an optical flow algorithm. Features are tracked from frame to frame so as to obtain more reliable estimates of their motion. Corrections are made to motion parameters with the residual disparities using a robust method, and features having large residual disparities are signaled as obstacles. Sensitivity analysis of the procedure is also studied. Nelson's optical flow constraint is proposed to separate moving obstacles from stationary ones. A Bayesian framework is used at every stage so that the confidence in the estimates can be determined.

Physical Activity Disparities in Heterosexual and Sexual Minority Youth Ages 12-22 Years Old: Roles of Childhood Gender Nonconformity and Athletic Self-Esteem

PubMed Central

Calzo, Jerel P.; Roberts, Andrea L.; Corliss, Heather L.; Blood, Emily A.; Kroshus, Emily; Austin, S. Bryn

2014-01-01

Background Physical activity is an important health determinant. Little is known about sexual orientation differences in physical activity and their psychosocial determinants. Purpose To examine adolescent and young adult hours/week of moderate/vigorous physical activity (MVPA) and team sports participation by sexual orientation and investigate contributions of gender nonconformity and low athletic self-esteem to possible sexual orientation differences. Methods Analysis of data from 5,272 males and 7,507 females from 1999-2005 waves of the US Growing Up Today Study (ages 12-22 years). Results Sexual minorities (i.e., lesbian, gay, bisexual, mostly heterosexual) reported 1.21-2.62 hours/week less MVPA (p's<0.01) and were 46%-76% less likely to participate in team sports than same-gender heterosexuals. Gender nonconformity and athletic self-esteem accounted for 46%-100% of sexual orientation MVPA differences. Conclusions Physical activity contexts should be modified to welcome sexual minority males and females. Targeting intolerance of gender nonconformity and fostering athletic self-esteem may mitigate sexual orientation MVPA disparities. PMID:24347406

Innovative Model of Practice-Oriented Training of Employees of the Town-Forming Enterprise in the Mining Region (by the Example of JSC "SUEK-Kuzbass")

NASA Astrophysics Data System (ADS)

Kulay, Svetlana; Kayachev, Gennady

2017-11-01

The article proposes to improve the system of training of employees of joint-stock company SUEK-Kuzbass in the educational institutions of the Kemerovo region according to the requirements of the company using practice-oriented training technology. The aim of the work is to substantiate the effectiveness of implementing practice-oriented training, identify priority directions and ways of its development. The main objectives of the study are: to identify the main advantages for the company and students; determine the criteria for the success and practical value of applying practice-oriented training for the company; conduct a comparative analysis of the target and practice-oriented model of training for the company. The real needs of the employer through the dual form of training were taking into account. The expansion of positive experience in training engineering personnel in higher education in technology-based training with the involvement of specialists from other regions of the company and expanding training in mining was also included.

Physical activity disparities in heterosexual and sexual minority youth ages 12-22 years old: roles of childhood gender nonconformity and athletic self-esteem.

PubMed

Calzo, Jerel P; Roberts, Andrea L; Corliss, Heather L; Blood, Emily A; Kroshus, Emily; Austin, S Bryn

2014-02-01

Physical activity is an important health determinant. Little is known about sexual orientation differences in physical activity and their psychosocial determinants. The aim of this study is to examine adolescent and young adult hours/week of moderate/vigorous physical activity (MVPA) and team sports participation by sexual orientation and investigate contributions of gender nonconformity and low athletic self-esteem to possible sexual orientation differences. Analysis of data from 5,272 males and 7,507 females from 1999 to 2005 waves of the US Growing Up Today Study (ages 12-22 years). Sexual minorities (i.e., lesbian, gay, bisexual, mostly heterosexual) reported 1.21-2.62 h/week less MVPA (p < 0.01) and were 46-76 % less likely to participate in team sports than same-gender heterosexuals. Gender nonconformity and athletic self-esteem accounted for 46-100 % of sexual orientation MVPA differences. Physical activity contexts should be modified to welcome sexual minority males and females. Targeting intolerance of gender nonconformity and fostering athletic self-esteem may mitigate sexual orientation MVPA disparities.

Development of a residual acceleration data reduction and dissemination plan

NASA Technical Reports Server (NTRS)

Rogers, Melissa J. B.

1992-01-01

A major obstacle in evaluating the residual acceleration environment in an orbiting space laboratory is the amount of data collected during a given mission: gigabytes of data will be available as SAMS units begin to fly regularly. Investigators taking advantage of the reduced gravity conditions of space should not be overwhelmed by the accelerometer data which describe these conditions. We are therefore developing a data reduction and analysis plan that will allow principal investigators of low-g experiments to create experiment-specific residual acceleration data bases for post-flight analysis. The basic aspects of the plan can also be used to characterize the acceleration environment of earth orbiting laboratories. Our development of the reduction plan is based on the following program of research: the identification of experiment sensitivities by order of magnitude estimates and numerical modelling; evaluation of various signal processing techniques appropriate for the reduction, supplementation, and dissemination of residual acceleration data; and testing and implementation of the plan on existing acceleration data bases. The orientation of the residual acceleration vector with respect to some set of coordinate axes is important for experiments with known directional sensitivity. Orientation information can be obtained from the evaluation of direction cosines. Fourier analysis is commonly used to transform time history data into the frequency domain. Common spectral representations are the amplitude spectrum which gives the average of the components of the time series at each frequency and the power spectral density which indicates the power or energy present in the series per unit frequency interval. The data reduction and analysis scheme developed involves a two tiered structure to: (1) identify experiment characteristics and mission events that can be used to limit the amount of accelerator data an investigator should be interested in; and (2) process the data in a way that will be meaningful to the experiment objectives. A general outline of the plan is given.

Exploring intentions of physician-scientist trainees: factors influencing MD and MD/PhD interest in research careers.

PubMed

Kwan, Jennifer M; Daye, Dania; Schmidt, Mary Lou; Conlon, Claudia Morrissey; Kim, Hajwa; Gaonkar, Bilwaj; Payne, Aimee S; Riddle, Megan; Madera, Sharline; Adami, Alexander J; Winter, Kate Quinn

2017-07-11

Prior studies have described the career paths of physician-scientist candidates after graduation, but the factors that influence career choices at the candidate stage remain unclear. Additionally, previous work has focused on MD/PhDs, despite many physician-scientists being MDs. This study sought to identify career sector intentions, important factors in career selection, and experienced and predicted obstacles to career success that influence the career choices of MD candidates, MD candidates with research-intense career intentions (MD-RI), and MD/PhD candidates. A 70-question survey was administered to students at 5 academic medical centers with Medical Scientist Training Programs (MSTPs) and Clinical and Translational Science Awards (CTSA) from the NIH. Data were analyzed using bivariate or multivariate analyses. More MD/PhD and MD-RI candidates anticipated or had experienced obstacles related to balancing academic and family responsibilities and to balancing clinical, research, and education responsibilities, whereas more MD candidates indicated experienced and predicted obstacles related to loan repayment. MD/PhD candidates expressed higher interest in basic and translational research compared to MD-RI candidates, who indicated more interest in clinical research. Overall, MD-RI candidates displayed a profile distinct from both MD/PhD and MD candidates. MD/PhD and MD-RI candidates experience obstacles that influence their intentions to pursue academic medical careers from the earliest training stage, obstacles which differ from those of their MD peers. The differences between the aspirations of and challenges facing MD, MD-RI and MD/PhD candidates present opportunities for training programs to target curricula and support services to ensure the career development of successful physician-scientists.

Curriculum Reform in Mathematics and the Target Oriented Curriculum.

ERIC Educational Resources Information Center

Fung, Chun Ip

1995-01-01

Highlights issues and ideas in the reform of school mathematics curricula with reference to Australia, the United Kingdom, and the United States. Interprets the ideas set out in documents related to the Target Oriented Curriculum (TOC) initiative in Hong Kong. Discusses factors that hinder the implementation of the TOC. (DSK)

Teachers' Stages of Concern about the Target-Oriented Curriculum.

ERIC Educational Resources Information Center

Cheung, Derek; Ng, Davis

2000-01-01

Investigates teachers' concerns about the Target-Oriented Curriculum (TOC) in Hong Kong (China). Finds that most teachers showed concern about the management of TOC (found in the third stage) and most were concerned with efficiency, time demands, organization, scheduling, and the best use of resources. Includes references. (CMK)

An intelligent, free-flying robot

NASA Technical Reports Server (NTRS)

Reuter, G. J.; Hess, C. W.; Rhoades, D. E.; Mcfadin, L. W.; Healey, K. J.; Erickson, J. D.

1988-01-01

The ground-based demonstration of EVA Retriever, a voice-supervised, intelligent, free-flying robot, is designed to evaluate the capability to retrieve objects (astronauts, equipment, and tools) which have accidentally separated from the Space Station. The major objective of the EVA Retriever Project is to design, develop, and evaluate an integrated robotic hardware and on-board software system which autonomously: (1) performs system activation and check-out, (2) searches for and acquires the target, (3) plans and executes a rendezvous while continuously tracking the target, (4) avoids stationary and moving obstacles, (5) reaches for and grapples the target, (6) returns to transfer the object, and (7) returns to base.

An intelligent, free-flying robot

NASA Technical Reports Server (NTRS)

Reuter, G. J.; Hess, C. W.; Rhoades, D. E.; Mcfadin, L. W.; Healey, K. J.; Erickson, J. D.; Phinney, Dale E.

1989-01-01

The ground based demonstration of the extensive extravehicular activity (EVA) Retriever, a voice-supervised, intelligent, free flying robot, is designed to evaluate the capability to retrieve objects (astronauts, equipment, and tools) which have accidentally separated from the Space Station. The major objective of the EVA Retriever Project is to design, develop, and evaluate an integrated robotic hardware and on-board software system which autonomously: (1) performs system activation and check-out; (2) searches for and acquires the target; (3) plans and executes a rendezvous while continuously tracking the target; (4) avoids stationary and moving obstacles; (5) reaches for and grapples the target; (6) returns to transfer the object; and (7) returns to base.

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

Asymmetries in visual search for conjunctive targets.

PubMed

Cohen, A

1993-08-01

Asymmetry is demonstrated between conjunctive targets in visual search with no detectable asymmetries between the individual features that compose these targets. Experiment 1 demonstrated this phenomenon for targets composed of color and shape. Experiment 2 and 4 demonstrate this asymmetry for targets composed of size and orientation and for targets composed of contrast level and orientation, respectively. Experiment 3 demonstrates that search rate of individual features cannot predict search rate for conjunctive targets. These results demonstrate the need for 2 levels of representations: one of features and one of conjunction of features. A model related to the modified feature integration theory is proposed to account for these results. The proposed model and other models of visual search are discussed.

EMEN2: An Object Oriented Database and Electronic Lab Notebook

PubMed Central

Rees, Ian; Langley, Ed; Chiu, Wah; Ludtke, Steven J.

2013-01-01

Transmission electron microscopy and associated methods such as single particle analysis, 2-D crystallography, helical reconstruction and tomography, are highly data-intensive experimental sciences, which also have substantial variability in experimental technique. Object-oriented databases present an attractive alternative to traditional relational databases for situations where the experiments themselves are continually evolving. We present EMEN2, an easy to use object-oriented database with a highly flexible infrastructure originally targeted for transmission electron microscopy and tomography, which has been extended to be adaptable for use in virtually any experimental science. It is a pure object-oriented database designed for easy adoption in diverse laboratory environments, and does not require professional database administration. It includes a full featured, dynamic web interface in addition to APIs for programmatic access. EMEN2 installations currently support roughly 800 scientists worldwide with over 1/2 million experimental records and over 20 TB of experimental data. The software is freely available with complete source. PMID:23360752

A Performance Management Framework for Civil Engineering

DTIC Science & Technology

1990-09-01

cultural change. A non - equivalent control group design was chosen to augment the case analysis. Figure 3.18 shows the form of the quasi-experiment. The...The non - equivalent control group design controls the following obstacles to internal validity: history, maturation, testing, and instrumentation. The...and Stanley, 1963:48,50) Table 7. Validity of Quasi-Experiment The non - equivalent control group experimental design controls the following obstacles to

Targeting receptor-mediated transport for delivery of biologics across the blood-brain barrier.

PubMed

Lajoie, Jason M; Shusta, Eric V

2015-01-01

Biologics are an emerging class of medicines with substantial promise to treat neurological disorders such as Alzheimer's disease, stroke, and multiple sclerosis. However, the blood-brain barrier (BBB) presents a formidable obstacle that appreciably limits brain uptake and hence the therapeutic potential of biologics following intravenous administration. One promising strategy for overcoming the BBB to deliver biologics is the targeting of endogenous receptor-mediated transport (RMT) systems that employ vesicular trafficking to transport ligands across the BBB endothelium. If a biologic is modified with an appropriate targeting ligand, it can gain improved access to the brain via RMT. Various RMT-targeting strategies have been developed over the past 20 years, and this review explores exciting recent advances, emphasizing studies that show brain targeting in vivo.

Nucleic Acid Aptamer-Guided Cancer Therapeutics and Diagnostics: the Next Generation of Cancer Medicine

PubMed Central

Xiang, Dongxi; Shigdar, Sarah; Qiao, Greg; Wang, Tao; Kouzani, Abbas Z.; Zhou, Shu-Feng; Kong, Lingxue; Li, Yong; Pu, Chunwen; Duan, Wei

2015-01-01

Conventional anticancer therapies, such as chemo- and/or radio-therapy are often unable to completely eradicate cancers due to abnormal tumor microenvironment, as well as increased drug/radiation resistance. More effective therapeutic strategies for overcoming these obstacles are urgently in demand. Aptamers, as chemical antibodies that bind to targets with high affinity and specificity, are a promising new and novel agent for both cancer diagnostic and therapeutic applications. Aptamer-based cancer cell targeting facilitates the development of active targeting in which aptamer-mediated drug delivery could provide promising anticancer outcomes. This review is to update the current progress of aptamer-based cancer diagnosis and aptamer-mediated active targeting for cancer therapy in vivo, exploring the potential of this novel form of targeted cancer therapy. PMID:25553096

Nucleic acid aptamer-guided cancer therapeutics and diagnostics: the next generation of cancer medicine.

PubMed

Xiang, Dongxi; Shigdar, Sarah; Qiao, Greg; Wang, Tao; Kouzani, Abbas Z; Zhou, Shu-Feng; Kong, Lingxue; Li, Yong; Pu, Chunwen; Duan, Wei

2015-01-01

Conventional anticancer therapies, such as chemo- and/or radio-therapy are often unable to completely eradicate cancers due to abnormal tumor microenvironment, as well as increased drug/radiation resistance. More effective therapeutic strategies for overcoming these obstacles are urgently in demand. Aptamers, as chemical antibodies that bind to targets with high affinity and specificity, are a promising new and novel agent for both cancer diagnostic and therapeutic applications. Aptamer-based cancer cell targeting facilitates the development of active targeting in which aptamer-mediated drug delivery could provide promising anticancer outcomes. This review is to update the current progress of aptamer-based cancer diagnosis and aptamer-mediated active targeting for cancer therapy in vivo, exploring the potential of this novel form of targeted cancer therapy.

AUTISTIC TRAITS INFLUENCE GAZE-ORIENTED ATTENTION TO HAPPY BUT NOT FEARFUL FACES

PubMed Central

Lassalle, Amandine; Itier, Roxane J.

2017-01-01

The relationship between autistic traits and gaze-oriented attention to fearful and happy faces was investigated at the behavioral and neuronal levels. Upright and inverted dynamic face stimuli were used in a gaze-cueing paradigm while ERPs were recorded. Participants responded faster to gazed-at than to non-gazed-at targets and this Gaze Orienting Effect (GOE) diminished with inversion, suggesting it relies on facial configuration. It was also larger for fearful than happy faces but only in participants with high Autism Quotient (AQ) scores. While the GOE to fearful faces was of similar magnitude regardless of AQ scores, a diminished GOE to happy faces was found in participants with high AQ scores. At the ERP level, a congruency effect on target-elicited P1 component reflected enhanced visual processing of gazed-at targets. In addition, cue-triggered early directing attention negativity and anterior directing attention negativity reflected, respectively, attention orienting and attention holding at gazed-at locations. These neural markers of spatial attention orienting were not modulated by emotion and were not found in participants with high AQ scores. Together these findings suggest that autistic traits influence attention orienting to gaze and its modulation by social emotions such as happiness. PMID:25222883

Low-resolution ship detection from high-altitude aerial images

NASA Astrophysics Data System (ADS)

Qi, Shengxiang; Wu, Jianmin; Zhou, Qing; Kang, Minyang

2018-02-01

Ship detection from optical images taken by high-altitude aircrafts such as unmanned long-endurance airships and unmanned aerial vehicles has broad applications in marine fishery management, ship monitoring and vessel salvage. However, the major challenge is the limited capability of information processing on unmanned high-altitude platforms. Furthermore, in order to guarantee the wide detection range, unmanned aircrafts generally cruise at high altitudes, resulting in imagery with low-resolution targets and strong clutters suffered by heavy clouds. In this paper, we propose a low-resolution ship detection method to extract ships from these high-altitude optical images. Inspired by a recent research on visual saliency detection indicating that small salient signals could be well detected by a gradient enhancement operation combined with Gaussian smoothing, we propose the facet kernel filtering to rapidly suppress cluttered backgrounds and delineate candidate target regions from the sea surface. Then, the principal component analysis (PCA) is used to compute the orientation of the target axis, followed by a simplified histogram of oriented gradient (HOG) descriptor to characterize the ship shape property. Finally, support vector machine (SVM) is applied to discriminate real targets and false alarms. Experimental results show that the proposed method actually has high efficiency in low-resolution ship detection.

"Everyone just keeps their eyes closed and their fingers crossed": sexual health communication among black parents and children in Nova Scotia, Canada.

PubMed

Davis, Antoinette N; Gahagan, Jacqueline C; George, Clemon

2013-07-22

Black Canadian youth remain disproportionally affected by an array of social and health issues, including sexually transmitted infections. While research exists in support of the involvement of parents as a key means to prevent or modify harmful behaviours among youth, less is known about how parent-child communication can serve as a prevention intervention strategy within Black families in Canada. This study explores sexual health communication between Black parents and youth in Nova Scotia and identifies facilitators, obstacles and issues that families face in dialoguing about sexual health. Focus groups and in-depth interview sessions were held with a diverse sample of parents of Black youth, health and education professionals, and Black youth in Nova Scotia, as part of a larger study aimed at exploring parent-child communication on sexual health and HIV. The research team worked in partnership with and received feedback from key informants and a community advisory committee throughout the various stages of this study. All sessions were audio-taped with permission and thematic analysis was carried out on the verbatim transcripts. Six key themes emerged from the data analysis in relation to parent-child communication within Black families in Nova Scotia: 1. the gendered nature of [sexual] health communication; 2. fear and uncertainty as obstacles; 3. open and honest dialogue from an early age as a facilitator; 4. media as both a catalyst and a barrier; 5. peers as a catalyst; and 6. time constraints as an obstacle. The findings of this study reveal that parent-child communication regarding sexual health promotion within Black families in Nova Scotia remains varied and is heavily affected by a myriad of intersecting determinants of health faced by Black youth and their parents. Health promotion interventions aimed at fostering and supporting parent-child communication on sexual health must simultaneously target both parents and youth and further, such efforts must engage a high level of cultural competency in order to better meet the needs of this population.

“Everyone just keeps their eyes closed and their fingers crossed”: Sexual health communication among black parents and children in Nova Scotia, Canada

PubMed Central

2013-01-01

Background Black Canadian youth remain disproportionally affected by an array of social and health issues, including sexually transmitted infections. While research exists in support of the involvement of parents as a key means to prevent or modify harmful behaviours among youth, less is known about how parent–child communication can serve as a prevention intervention strategy within Black families in Canada. This study explores sexual health communication between Black parents and youth in Nova Scotia and identifies facilitators, obstacles and issues that families face in dialoguing about sexual health. Methods Focus groups and in-depth interview sessions were held with a diverse sample of parents of Black youth, health and education professionals, and Black youth in Nova Scotia, as part of a larger study aimed at exploring parent–child communication on sexual health and HIV. The research team worked in partnership with and received feedback from key informants and a community advisory committee throughout the various stages of this study. All sessions were audio-taped with permission and thematic analysis was carried out on the verbatim transcripts. Results Six key themes emerged from the data analysis in relation to parent–child communication within Black families in Nova Scotia: 1. the gendered nature of [sexual] health communication; 2. fear and uncertainty as obstacles; 3. open and honest dialogue from an early age as a facilitator; 4. media as both a catalyst and a barrier; 5. peers as a catalyst; and 6. time constraints as an obstacle. Conclusions The findings of this study reveal that parent–child communication regarding sexual health promotion within Black families in Nova Scotia remains varied and is heavily affected by a myriad of intersecting determinants of health faced by Black youth and their parents. Health promotion interventions aimed at fostering and supporting parent–child communication on sexual health must simultaneously target both parents and youth and further, such efforts must engage a high level of cultural competency in order to better meet the needs of this population. PMID:23876177

Human spatial orientation in the pitch dimension

NASA Technical Reports Server (NTRS)

Cohen, M. M.; Larson, C. A.

1974-01-01

Two experiments were conducted. In Experiment I, each of eight Ss attempted to place himself at 13 different goal orientations between prone and supine. Deviations of achieved body pitch angles from goal orientations were determined. In Experiment II, each of eight Ss attempted to align a visual target with his morphological horizon while he was placed at each of the 13 goal orientations. Changes in settings of the target were examined. Results indicate that Ss underestimate body pitch when they are tilted less than 60 deg backward or forward from the vertical, overestimate body pitch when they are nearly prone, and accurately estimate body pitch when they are nearly supine. In contrast, Ss set the visual target maximally above the morphological horizon when they are tilted 30 deg forward from the vertical. The findings are discussed in terms of common and different physiological mechanism that may underlie judgments of these types.

Response to Intervention and Authentic Assessment

ERIC Educational Resources Information Center

McCrary, Donna; Brown, David L.; Dyer-Sennette, Jennifer; Morton, Tami

2017-01-01

The brief description of a real child presented in this article highlights some of the obstacles faced by many children in the United States today, particularly those who come from low-income homes. There is an increasingly large chasm between the number of children who are on target for success in school and those who need extra help to close…

Experimental and simulation study results of an Adaptive Video Guidance System /AVGS/

NASA Technical Reports Server (NTRS)

Schappell, R. T.; Knickerbocker, R. L.

1975-01-01

Studies relating to stellar-body exploration programs have pointed out the need for an adaptive guidance scheme capable of providing automatic real-time guidance and site selection capability. For the case of a planetary lander, without such guidance, targeting is limited to what are believed to be generally benign areas in order to ensure a reasonable landing-success probability. Typically, the Mars Viking Lander will be jeopardized by obstacles exceeding 22 centimers in diameter. The benefits of on-board navigation and real-time selection of a landing site and obstacle avoidance have been demonstrated by the Apollo lunar landings, in which man performed the surface sensing and steering functions. Therefore, an Adaptive Video Guidance System (AVGS) has been developed, bread-boarded, and flown on a six-degree-of-freedom simulator.

[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.

Brain networks of temporal preparation: A multiple regression analysis of neuropsychological data.

PubMed

Triviño, Mónica; Correa, Ángel; Lupiáñez, Juan; Funes, María Jesús; Catena, Andrés; He, Xun; Humphreys, Glyn W

2016-11-15

There are only a few studies on the brain networks involved in the ability to prepare in time, and most of them followed a correlational rather than a neuropsychological approach. The present neuropsychological study performed multiple regression analysis to address the relationship between both grey and white matter (measured by magnetic resonance imaging in patients with brain lesion) and different effects in temporal preparation (Temporal orienting, Foreperiod and Sequential effects). Two versions of a temporal preparation task were administered to a group of 23 patients with acquired brain injury. In one task, the cue presented (a red versus green square) to inform participants about the time of appearance (early versus late) of a target stimulus was blocked, while in the other task the cue was manipulated on a trial-by-trial basis. The duration of the cue-target time intervals (400 versus 1400ms) was always manipulated within blocks in both tasks. Regression analysis were conducted between either the grey matter lesion size or the white matter tracts disconnection and the three temporal preparation effects separately. The main finding was that each temporal preparation effect was predicted by a different network of structures, depending on cue expectancy. Specifically, the Temporal orienting effect was related to both prefrontal and temporal brain areas. The Foreperiod effect was related to right and left prefrontal structures. Sequential effects were predicted by both parietal cortex and left subcortical structures. These findings show a clear dissociation of brain circuits involved in the different ways to prepare in time, showing for the first time the involvement of temporal areas in the Temporal orienting effect, as well as the parietal cortex in the Sequential effects. Copyright © 2016 Elsevier Inc. All rights reserved.

Object Selection Costs in Visual Working Memory: A Diffusion Model Analysis of the Focus of Attention

ERIC Educational Resources Information Center

Sewell, David K.; Lilburn, Simon D.; Smith, Philip L.

2016-01-01

A central question in working memory research concerns the degree to which information in working memory is accessible to other cognitive processes (e.g., decision-making). Theories assuming that the focus of attention can only store a single object at a time require the focus to orient to a target representation before further processing can…

An approach to studying scale for students in higher education: a Rasch measurement model analysis.

PubMed

Waugh, R F; Hii, T K; Islam, A

2000-01-01

A questionnaire comprising 80 self-report items was designed to measure student Approaches to Studying in a higher education context. The items were conceptualized and designed from five learning orientations: a Deep Approach, a Surface Approach, a Strategic Approach, Clarity of Direction and Academic Self-Confidence, to include 40 attitude items and 40 corresponding behavior items. The study aimed to create a scale and investigate its psychometric properties using a Rasch measurement model. The convenience sample consisted of 350 students at an Australian university in 1998. The analysis supported the conceptual structure of the Scale as involving studying attitudes and behaviors towards five orientations to learning. Attitudes are mostly easier than behaviors, in line with the theory. Sixty-eight items fit the model and have good psychometric properties. The proportion of observed variance considered true is 92% and the Scale is well-targeted against the students. Some harder items are needed to improve the targeting and some further testing work needs to be done on the Surface Approach. In the Surface Approach and Clarity of Direction in Studying, attitudes make a lesser contribution than behaviors to the variable, Approaches to Studying.

Neural correlates of the spatial and expectancy components of endogenous and stimulus-driven orienting of attention in the Posner task.

PubMed

Doricchi, Fabrizio; Macci, Enrica; Silvetti, Massimo; Macaluso, Emiliano

2010-07-01

Voluntary orienting of visual attention is conventionally measured in tasks with predictive central cues followed by frequent valid targets at the cued location and by infrequent invalid targets at the uncued location. This implies that invalid targets entail both spatial reorienting of attention and breaching of the expected spatial congruency between cues and targets. Here, we used event-related functional magnetic resonance imaging (fMRI) to separate the neural correlates of the spatial and expectancy components of both endogenous orienting and stimulus-driven reorienting of attention. We found that during endogenous orienting with predictive cues, there was a significant deactivation of the right Temporal-Parietal Junction (TPJ). We also discovered that the lack of an equivalent deactivation with nonpredictive cues was matched to drop in attentional costs and preservation of attentional benefits. The right TPJ showed equivalent responses to invalid targets following predictive and nonpredictive cues. On the contrary, infrequent-unexpected invalid targets following predictive cues specifically activated the right Middle and Inferior Frontal Gyrus (MFG-IFG). Additional comparisons with spatially neutral trials demonstrated that, independently of cue predictiveness, valid targets activate the left TPJ, whereas invalid targets activate both the left and right TPJs. These findings show that the selective right TPJ activation that is found in the comparison between invalid and valid trials results from the reciprocal cancelling of the different activations that in the left TPJ are related to the processing of valid and invalid targets. We propose that left and right TPJs provide "matching and mismatching to attentional template" signals. These signals enable reorienting of attention and play a crucial role in the updating of the statistical contingency between cues and targets.

Analysis of Photogrammetry Data from ISIM Mockup, June 1, 2007

NASA Technical Reports Server (NTRS)

Nowak, Maria; Hill, Mike

2007-01-01

During ground testing of the Integrated Science Instrument Module (ISIM) for the James Webb Space Telescope (JWST), the ISIM Optics group plans to use a Photogrammetry Measurement System for cryogenic calibration of specific target points on the ISIM composite structure and Science Instrument optical benches and other GSE equipment. This testing will occur in the Space Environmental Systems (SES) chamber at Goddard Space Flight Center. Close range photogrammetry is a 3 dimensional metrology system using triangulation to locate custom targets in 3 coordinates via a collection of digital photographs taken from various locations and orientations. These photos are connected using coded targets, special targets that are recognized by the software and can thus correlate the images to provide a 3 dimensional map of the targets, and scaled via well calibrated scale bars. Photogrammetry solves for the camera location and coordinates of the targets simultaneously through the bundling procedure contained in the V-STARS software.

Decomposition of the Multistatic Response Matrix and Target Characterization

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

Chambers, D H

2008-02-14

Decomposition of the time-reversal operator for an array, or equivalently the singular value decomposition of the multistatic response matrix, has been used to improve imaging and localization of targets in complicated media. Typically, each singular value is associated with one scatterer even though it has been shown in several cases that a single scatterer can generate several singular values. In this paper we review the analysis of the time-reversal operator (TRO), or equivalently the multistatic response matrix (MRM), of an array system and a small target. We begin with two-dimensional scattering from a small cylinder then show the results formore » a small non-spherical target in three dimensions. We show that the number and magnitudes of the singular values contain information about target composition, shape, and orientation.« less

Perspectives on the Cultural Appropriacy of Hong Kong's Target-Oriented Curriculum (TOC) Initiative.

ERIC Educational Resources Information Center

Carless, David Robert

1999-01-01

Explores the impact of Chinese culture on the school curriculum in Hong Kong. Argues that the Target-Oriented Curriculum (TOC) transplanted from western-based concepts is not commensurate with the local Chinese cultural context, and therefore leads to many problems when being implemented in schools. (Author/VWL)

Acting Diverse: Target Group Orientation as Key Competence in Engineering Education

ERIC Educational Resources Information Center

Ihsen, S.; Buschmeyer, A.

2007-01-01

International companies are recognised by equity between men and women as well as between other different groups (Diversity) as an economic factor and incorporate it into their company visions. Mixed teams are set up to design target group-oriented products, for example in automotive engineering. Therefore they need employees who represent the…

On the rules of integration of crowded orientation signals

PubMed Central

Põder, Endel

2012-01-01

Crowding is related to an integration of feature signals over an inappropriately large area in the visual periphery. The rules of this integration are still not well understood. This study attempts to understand how the orientation signals from the target and flankers are combined. A target Gabor, together with 2, 4, or 6 flanking Gabors, was briefly presented in a peripheral location (4° eccentricity). The observer's task was to identify the orientation of the target (eight-alternative forced-choice). Performance was found to be nonmonotonically dependent on the target–flanker orientation difference (a drop at intermediate differences). For small target–flanker differences, a strong assimilation bias was observed. An effect of the number of flankers was found for heterogeneous flankers only. It appears that different rules of integration are used, dependent on some salient aspects (target pop-out, homogeneity–heterogeneity) of the stimulus pattern. The strategy of combining simple rules may be explained by the goal of the visual system to encode potentially important aspects of a stimulus with limited processing resources and using statistical regularities of the natural visual environment. PMID:23145295

Nanozeolite bioconjugates labeled with 223Ra for targeted alpha therapy.

PubMed

Piotrowska, Agata; Męczyńska-Wielgosz, Sylwia; Majkowska-Pilip, Agnieszka; Koźmiński, Przemysław; Wójciuk, Grzegorz; Cędrowska, Edyta; Bruchertseifer, Frank; Morgenstern, Alfred; Kruszewski, Marcin; Bilewicz, Aleksander

2017-04-01

Alpha particle emitting isotopes are of considerable interest for radionuclide therapy because of their high cytotoxicity and short path length. Among the many α emitters, 223 Ra exhibits very attractive nuclear properties for application in radionuclide therapy. The decay of this radioisotope and its daughters is accompanied by the emission of four α-particles, releasing 27.9MeV of cumulative energy. Unfortunately the lack of an appropriate bifunctional ligand for radium has so far been a main obstacle for the application of 223 Ra in receptor targeted therapy. In our studies we investigated the use of nanozeolite-Substance P bioconjugates as vehicles for 223 Ra radionuclides for targeted α therapy. The sodium form of an A-type of nanozeolite (NaA) was synthesized using the template method. Next, the nanozeolite particles were conjugated to the Substance P (5-11) peptide fragment, which targets NK-1 receptors on glioma cells. The obtained bioconjugate was characterized by transmission emission spectroscopy, thermogravimetric analysis and dynamic light scattering analysis. The NaA-silane-PEG-SP(5-11) bioconjugates were labeled with 223 Ra by exchange of the Na + cation and the stability, receptor affinity and cytotoxicity of the obtained radiobioconjugates were tested. The 223 Ra-labeled nanozeolite bioconjugate almost quantitatively retains 223 Ra in vitro after 6days, while the retention of decay products varies from 90 to 95%. The synthesized 223 RaA-silane-PEG-SP(5-11) showed high receptor affinity toward NK-1 receptor expressing glioma cells and exhibited a high cytotoxic effect in vitro. Substance P functionalized nanozeolite-A represents a viable solution for the use of the 223 Ra in vivo generator as a therapeutic construct for targeting glioma cells. Copyright © 2016 Elsevier Inc. All rights reserved.

Overt attention toward oriented objects in free-viewing barn owls.

PubMed

Harmening, Wolf Maximilian; Orlowski, Julius; Ben-Shahar, Ohad; Wagner, Hermann

2011-05-17

Visual saliency based on orientation contrast is a perceptual product attributed to the functional organization of the mammalian brain. We examined this visual phenomenon in barn owls by mounting a wireless video microcamera on the owls' heads and confronting them with visual scenes that contained one differently oriented target among similarly oriented distracters. Without being confined by any particular task, the owls looked significantly longer, more often, and earlier at the target, thus exhibiting visual search strategies so far demonstrated in similar conditions only in primates. Given the considerable differences in phylogeny and the structure of visual pathways between owls and humans, these findings suggest that orientation saliency has computational optimality in a wide variety of ecological contexts, and thus constitutes a universal building block for efficient visual information processing in general.

EEG Correlates of Preparatory Orienting, Contextual Updating, and Inhibition of Sensory Processing in Left Spatial Neglect.

PubMed

Lasaponara, Stefano; D'Onofrio, Marianna; Pinto, Mario; Dragone, Alessio; Menicagli, Dario; Bueti, Domenica; De Lucia, Marzia; Tomaiuolo, Francesco; Doricchi, Fabrizio

2018-04-11

Studies with event-related potentials have highlighted deficits in the early phases of orienting to left visual targets in right-brain-damaged patients with left spatial neglect (N+). However, brain responses associated with preparatory orienting of attention, with target novelty and with the detection of a match/mismatch between expected and actual targets (contextual updating), have not been explored in N+. Here in a study in healthy humans and brain-damaged patients of both sexes we demonstrate that frontal activity that reflects supramodal mechanisms of attentional orienting (Anterior Directing Attention Negativity, ADAN) is entirely spared in N+. In contrast, posterior responses that mark the early phases of cued orienting (Early Directing Attention Negativity, EDAN) and the setting up of sensory facilitation over the visual cortex (Late Directing Attention Positivity, LDAP) are suppressed in N+. This uncoupling is associated with damage of parietal-frontal white matter. N+ also exhibit exaggerated novelty reaction to targets in the right side of space and reduced novelty reaction for those in the left side (P3a) together with impaired contextual updating (P3b) in the left space. Finally, we highlight a drop in the amplitude and latency of the P1 that over the left hemisphere signals the early blocking of sensory processing in the right space when targets occur in the left one: this identifies a new electrophysiological marker of the rightward attentional bias in N+. The heterogeneous effects and spatial biases produced by localized brain damage on the different phases of attentional processing indicate relevant functional independence among their underlying neural mechanisms and improve the understanding of the spatial neglect syndrome. SIGNIFICANCE STATEMENT Our investigation answers important questions: are the different components of preparatory orienting (EDAN, ADAN, LDAP) functionally independent in the healthy brain? Is preparatory orienting of attention spared in left spatial neglect? Does the sparing of preparatory orienting have an impact on deficits in reflexive orienting and in the assignment of behavioral relevance to the left space? We show that supramodal preparatory orienting in frontal areas is entirely spared in neglect patients though this does not counterbalance deficits in preparatory parietal-occipital activity, reflexive orienting, and contextual updating. This points at relevant functional dissociations among different components of attention and suggests that improving voluntary attention in N+ might be behaviorally ineffective unless associated with stimulations boosting the response of posterior parietal-occipital areas. Copyright © 2018 the authors 0270-6474/18/383792-17$15.00/0.

Development of an expert data reduction assistant

NASA Technical Reports Server (NTRS)

Miller, Glenn E.; Johnston, Mark D.; Hanisch, Robert J.

1992-01-01

We propose the development of an expert system tool for the management and reduction of complex data sets. The proposed work is an extension of a successful prototype system for the calibration of CCD images developed by Dr. Johnston in 1987. The reduction of complex multi-parameter data sets presents severe challenges to a scientist. Not only must a particular data analysis system be mastered, (e.g. IRAF/SDAS/MIDAS), large amounts of data can require many days of tedious work and supervision by the scientist for even the most straightforward reductions. The proposed Expert Data Reduction Assistant will help the scientist overcome these obstacles by developing a reduction plan based on the data at hand and producing a script for the reduction of the data in a target common language.

C-axis orientated AlN films deposited using deep oscillation magnetron sputtering

NASA Astrophysics Data System (ADS)

Lin, Jianliang; Chistyakov, Roman

2017-02-01

Highly <0001> c-axis orientated aluminum nitride (AlN) films were deposited on silicon (100) substrates by reactive deep oscillation magnetron sputtering (DOMS). No epitaxial favored bond layer and substrate heating were applied for assisting texture growth. The effects of the peak target current density (varied from 0.39 to 0.8 Acm-2) and film thickness (varied from 0.25 to 3.3 μm) on the c-axis orientation, microstructure, residual stress and mechanical properties of the AlN films were investigated by means of X-ray diffraction rocking curve methodology, transmission electron microscopy, optical profilometry, and nanoindentation. All AlN films exhibited a <0001> preferred orientation and compressive residual stresses. At similar film thicknesses, an increase in the peak target current density to 0.53 Acm-2 improved the <0001> orientation. Further increasing the peak target current density to above 0.53 Acm-2 showed limited contribution to the texture development. The study also showed that an increase in the thickness of the AlN films deposited by DOMS improved the c-axis alignment accompanied with a reduction in the residual stress.

Laser tracker orientation in confined space using on-board targets

NASA Astrophysics Data System (ADS)

Gao, Yang; Kyle, Stephen; Lin, Jiarui; Yang, Linghui; Ren, Yu; Zhu, Jigui

2016-08-01

This paper presents a novel orientation method for two laser trackers using on-board targets attached to the tracker head and rotating with it. The technique extends an existing method developed for theodolite intersection systems which are now rarely used. This method requires only a very narrow space along the baseline between the instrument heads, in order to establish the orientation relationship. This has potential application in environments where space is restricted. The orientation parameters can be calculated by means of two-face reciprocal measurements to the on-board targets, and measurements to a common point close to the baseline. An accurate model is then applied which can be solved through nonlinear optimization. Experimental comparison has been made with the conventional orientation method, which is based on measurements to common intersection points located off the baseline. This requires more space and the comparison has demonstrated the feasibility of the more compact technique presented here. Physical setup and testing suggest that the method is practical. Uncertainties estimated by simulation indicate good performance in terms of measurement quality.

Effect of Exogenous Cues on Covert Spatial Orienting in Deaf and Normal Hearing Individuals

PubMed Central

Prasad, Seema Gorur; Patil, Gouri Shanker; Mishra, Ramesh Kumar

2015-01-01

Deaf individuals have been known to process visual stimuli better at the periphery compared to the normal hearing population. However, very few studies have examined attention orienting in the oculomotor domain in the deaf, particularly when targets appear at variable eccentricity. In this study, we examined if the visual perceptual processing advantage reported in the deaf people also modulates spatial attentional orienting with eye movement responses. We used a spatial cueing task with cued and uncued targets that appeared at two different eccentricities and explored attentional facilitation and inhibition. We elicited both a saccadic and a manual response. The deaf showed a higher cueing effect for the ocular responses than the normal hearing participants. However, there was no group difference for the manual responses. There was also higher facilitation at the periphery for both saccadic and manual responses, irrespective of groups. These results suggest that, owing to their superior visual processing ability, the deaf may orient attention faster to targets. We discuss the results in terms of previous studies on cueing and attentional orienting in deaf. PMID:26517363

Effect of Exogenous Cues on Covert Spatial Orienting in Deaf and Normal Hearing Individuals.

PubMed

Prasad, Seema Gorur; Patil, Gouri Shanker; Mishra, Ramesh Kumar

2015-01-01

Deaf individuals have been known to process visual stimuli better at the periphery compared to the normal hearing population. However, very few studies have examined attention orienting in the oculomotor domain in the deaf, particularly when targets appear at variable eccentricity. In this study, we examined if the visual perceptual processing advantage reported in the deaf people also modulates spatial attentional orienting with eye movement responses. We used a spatial cueing task with cued and uncued targets that appeared at two different eccentricities and explored attentional facilitation and inhibition. We elicited both a saccadic and a manual response. The deaf showed a higher cueing effect for the ocular responses than the normal hearing participants. However, there was no group difference for the manual responses. There was also higher facilitation at the periphery for both saccadic and manual responses, irrespective of groups. These results suggest that, owing to their superior visual processing ability, the deaf may orient attention faster to targets. We discuss the results in terms of previous studies on cueing and attentional orienting in deaf.

A new high-resolution electromagnetic method for subsurface imaging

NASA Astrophysics Data System (ADS)

Feng, Wanjie

For most electromagnetic (EM) geophysical systems, the contamination of primary fields on secondary fields ultimately limits the capability of the controlled-source EM methods. Null coupling techniques were proposed to solve this problem. However, the small orientation errors in the null coupling systems greatly restrict the applications of these systems. Another problem encountered by most EM systems is the surface interference and geologic noise, which sometimes make the geophysical survey impossible to carry out. In order to solve these problems, the alternating target antenna coupling (ATAC) method was introduced, which greatly removed the influence of the primary field and reduced the surface interference. But this system has limitations on the maximum transmitter moment that can be used. The differential target antenna coupling (DTAC) method was proposed to allow much larger transmitter moments and at the same time maintain the advantages of the ATAC method. In this dissertation, first, the theoretical DTAC calculations were derived mathematically using Born and Wolf's complex magnetic vector. 1D layered and 2D blocked earth models were used to demonstrate that the DTAC method has no responses for 1D and 2D structures. Analytical studies of the plate model influenced by conductive and resistive backgrounds were presented to explain the physical phenomenology behind the DTAC method, which is the magnetic fields of the subsurface targets are required to be frequency dependent. Then, the advantages of the DTAC method, e.g., high-resolution, reducing the geologic noise and insensitive to surface interference, were analyzed using surface and subsurface numerical examples in the EMGIMA software. Next, the theoretical advantages, such as high resolution and insensitive to surface interference, were verified by designing and developing a low-power (moment of 50 Am 2) vertical-array DTAC system and testing it on controlled targets and scaled target coils. At last, a high-power (moment of about 6800 Am2) vertical-array DTAC system was designed, developed and tested on controlled buried targets and surface interference to illustrate that the DTAC system was insensitive to surface interference even with a high-power transmitter and having higher resolution by using the large-moment transmitter. From the theoretical and practical analysis and tests, several characteristics of the DTAC method were found: (1) The DTAC method can null out the effect of 1D layered and 2D structures, because magnetic fields are orientation independent which lead to no difference among the null vector directions. This characteristic allows for the measurements of smaller subsurface targets; (2) The DTAC method is insensitive to the orientation errors. It is a robust EM null coupling method. Even large orientation errors do not affect the measured target responses, when a reference frequency and one or more data frequencies are used; (3) The vertical-array DTAC method is effective in reducing the geologic noise and insensitive to the surface interference, e.g., fences, vehicles, power line and buildings; (4) The DTAC method is a high-resolution EM sounding method. It can distinguish the depth and orientation of subsurface targets; (5) The vertical-array DTAC method can be adapted to a variety of rapidly moving survey applications. The transmitter moment can be scaled for effective study of near-surface targets (civil engineering, water resource, and environmental restoration) as well as deep targets (mining and other natural-resource exploration).

A Dynamic Bioinspired Neural Network Based Real-Time Path Planning Method for Autonomous Underwater Vehicles

PubMed Central

2017-01-01

Real-time path planning for autonomous underwater vehicle (AUV) is a very difficult and challenging task. Bioinspired neural network (BINN) has been used to deal with this problem for its many distinct advantages: that is, no learning process is needed and realization is also easy. However, there are some shortcomings when BINN is applied to AUV path planning in a three-dimensional (3D) unknown environment, including complex computing problem when the environment is very large and repeated path problem when the size of obstacles is bigger than the detection range of sensors. To deal with these problems, an improved dynamic BINN is proposed in this paper. In this proposed method, the AUV is regarded as the core of the BINN and the size of the BINN is based on the detection range of sensors. Then the BINN will move with the AUV and the computing could be reduced. A virtual target is proposed in the path planning method to ensure that the AUV can move to the real target effectively and avoid big-size obstacles automatically. Furthermore, a target attractor concept is introduced to improve the computing efficiency of neural activities. Finally, some experiments are conducted under various 3D underwater environments. The experimental results show that the proposed BINN based method can deal with the real-time path planning problem for AUV efficiently. PMID:28255297

A Dynamic Bioinspired Neural Network Based Real-Time Path Planning Method for Autonomous Underwater Vehicles.

PubMed

Ni, Jianjun; Wu, Liuying; Shi, Pengfei; Yang, Simon X

2017-01-01

Real-time path planning for autonomous underwater vehicle (AUV) is a very difficult and challenging task. Bioinspired neural network (BINN) has been used to deal with this problem for its many distinct advantages: that is, no learning process is needed and realization is also easy. However, there are some shortcomings when BINN is applied to AUV path planning in a three-dimensional (3D) unknown environment, including complex computing problem when the environment is very large and repeated path problem when the size of obstacles is bigger than the detection range of sensors. To deal with these problems, an improved dynamic BINN is proposed in this paper. In this proposed method, the AUV is regarded as the core of the BINN and the size of the BINN is based on the detection range of sensors. Then the BINN will move with the AUV and the computing could be reduced. A virtual target is proposed in the path planning method to ensure that the AUV can move to the real target effectively and avoid big-size obstacles automatically. Furthermore, a target attractor concept is introduced to improve the computing efficiency of neural activities. Finally, some experiments are conducted under various 3D underwater environments. The experimental results show that the proposed BINN based method can deal with the real-time path planning problem for AUV efficiently.

Thermal energy storage for low grade heat in the organic Rankine cycle

NASA Astrophysics Data System (ADS)

Soda, Michael John

Limits of efficiencies cause immense amounts of thermal energy in the form of waste heat to be vented to the atmosphere. Up to 60% of unrecovered waste heat is classified as low or ultra-low quality, making recovery difficult or inefficient. The organic Rankine cycle can be used to generate mechanical power and electricity from these low temperatures where other thermal cycles are impractical. A variety of organic working fluids are available to optimize the ORC for any target temperature range. San Diego State University has one such experimental ORC using R245fa, and has been experimenting with multiple expanders. One limitation of recovering waste heat is the sporadic or cyclical nature common to its production. This inconsistency makes sizing heat recovery ORC systems difficult for a variety of reasons including off-design-point efficiency loss, increased attrition from varying loads, unreliable outputs, and overall system costs. Thermal energy storage systems can address all of these issues by smoothing the thermal input to a constant and reliable level and providing back-up capacity for times when the thermal input is deactivated. Multiple types of thermal energy storage have been explored including sensible, latent, and thermochemical. Latent heat storage involves storing thermal energy in the reversible phase change of a phase change material, or PCM, and can have several advantages over other modalities including energy storage density, cost, simplicity, reliability, relatively constant temperature output, and temperature customizability. The largest obstacles to using latent heat storage include heat transfer rates, thermal cycling stability, and potentially corrosive PCMs. Targeting 86°C, the operating temperature of SDSU's experimental ORC, multiple potential materials were explored and tested as potential PCMs including Magnesium Chloride Hexahydrate (MgCl2˙6H2O), Magnesium Nitrate Hexahydrate (Mg(NO3)2˙6H 2O), montan wax, and carnauba wax. The addition of graphite to augment heat transfer rates was also tested. Melting and solidification temperatures largely matched predictions. The magnesium salts were found to be less stable under thermal cycling than the waxes. Graphite was only soluble in the waxes. Mixtures of magnesium salts and waxes yielded a layered composite with the less dense waxes creating a sealing layer over the salt layer that significantly increased the stability of the magnesium salts. Research into optimum heat exchangers and storage vessels for these applications indicates that horizontally oriented aluminum pipes with vertically oriented aluminum fins would be the best method of storing and retrieving energy. Fin spacing can be predicted by an equation based on target temperatures and PCM characteristics.

Consumer behaviors towards ready-to-eat foods based on food-related lifestyles in Korea

PubMed Central

Bae, Hyun-Joo; Chae, Mi-Jin

2010-01-01

The purpose of this study was to examine consumers' behaviors toward ready-to-eat foods and to develop ready-to-eat food market segmentation in Korea. The food-related lifestyle and purchase behaviors of ready-to-eat foods were evaluated using 410 ready-to-eat food consumers in the Republic of Korea. Four factors were extracted by exploratory factor analysis (health-orientation, taste-orientation, convenience-orientation, and tradition-orientation) to explain the ready-to eat food consumers' food-related lifestyles. The results of cluster analysis indicated that "tradition seekers" and "convenience seekers" should be regarded as the target segments. Chi-square tests and t-tests of the subdivided groups showed there were significant differences across marital status, education level, family type, eating-out expenditure, place of purchase, and reason for purchase. In conclusion, the tradition seekers consumed more ready-to-eat foods from discount marts or specialty stores and ate them between meals more often than the convenience seekers. In contrast, the convenience seekers purchased more ready-to-eat foods at convenience stores and ate them as meals more often than the tradition seekers. These findings suggest that ready-to-eat food market segmentation based on food-related lifestyles can be applied to develop proper marketing strategies. PMID:20827350

Consumer behaviors towards ready-to-eat foods based on food-related lifestyles in Korea.

PubMed

Bae, Hyun-Joo; Chae, Mi-Jin; Ryu, Kisang

2010-08-01

The purpose of this study was to examine consumers' behaviors toward ready-to-eat foods and to develop ready-to-eat food market segmentation in Korea. The food-related lifestyle and purchase behaviors of ready-to-eat foods were evaluated using 410 ready-to-eat food consumers in the Republic of Korea. Four factors were extracted by exploratory factor analysis (health-orientation, taste-orientation, convenience-orientation, and tradition-orientation) to explain the ready-to eat food consumers' food-related lifestyles. The results of cluster analysis indicated that "tradition seekers" and "convenience seekers" should be regarded as the target segments. Chi-square tests and t-tests of the subdivided groups showed there were significant differences across marital status, education level, family type, eating-out expenditure, place of purchase, and reason for purchase. In conclusion, the tradition seekers consumed more ready-to-eat foods from discount marts or specialty stores and ate them between meals more often than the convenience seekers. In contrast, the convenience seekers purchased more ready-to-eat foods at convenience stores and ate them as meals more often than the tradition seekers. These findings suggest that ready-to-eat food market segmentation based on food-related lifestyles can be applied to develop proper marketing strategies.

Attention to baseline: does orienting visuospatial attention really facilitate target detection?

PubMed

Albares, Marion; Criaud, Marion; Wardak, Claire; Nguyen, Song Chi Trung; Ben Hamed, Suliann; Boulinguez, Philippe

2011-08-01

Standard protocols testing the orientation of visuospatial attention usually present spatial cues before targets and compare valid-cue trials with invalid-cue trials. The valid/invalid contrast results in a relative behavioral or physiological difference that is generally interpreted as a benefit of attention orientation. However, growing evidence suggests that inhibitory control of response is closely involved in this kind of protocol that requires the subjects to withhold automatic responses to cues, probably biasing behavioral and physiological baselines. Here, we used two experiments to disentangle the inhibitory control of automatic responses from orienting of visuospatial attention in a saccadic reaction time task in humans, a variant of the classical cue-target detection task and a sustained visuospatial attentional task. Surprisingly, when referring to a simple target detection task in which there is no need to refrain from reacting to avoid inappropriate responses, we found no consistent evidence of facilitation of target detection at the attended location. Instead, we observed a cost at the unattended location. Departing from the classical view, our results suggest that reaction time measures of visuospatial attention probably relie on the attenuation of elementary processes involved in visual target detection and saccade initiation away from the attended location rather than on facilitation at the attended location. This highlights the need to use proper control conditions in experimental designs to disambiguate relative from absolute cueing benefits on target detection reaction times, both in psychophysical and neurophysiological studies.

3D sensor algorithms for spacecraft pose determination

NASA Astrophysics Data System (ADS)

Trenkle, John M.; Tchoryk, Peter, Jr.; Ritter, Greg A.; Pavlich, Jane C.; Hickerson, Aaron S.

2006-05-01

Researchers at the Michigan Aerospace Corporation have developed accurate and robust 3-D algorithms for pose determination (position and orientation) of satellites as part of an on-going effort supporting autonomous rendezvous, docking and space situational awareness activities. 3-D range data from a LAser Detection And Ranging (LADAR) sensor is the expected input; however, the approach is unique in that the algorithms are designed to be sensor independent. Parameterized inputs allow the algorithms to be readily adapted to any sensor of opportunity. The cornerstone of our approach is the ability to simulate realistic range data that may be tailored to the specifications of any sensor. We were able to modify an open-source raytracing package to produce point cloud information from which high-fidelity simulated range images are generated. The assumptions made in our experimentation are as follows: 1) we have access to a CAD model of the target including information about the surface scattering and reflection characteristics of the components; 2) the satellite of interest may appear at any 3-D attitude; 3) the target is not necessarily rigid, but does have a limited number of configurations; and, 4) the target is not obscured in any way and is the only object in the field of view of the sensor. Our pose estimation approach then involves rendering a large number of exemplars (100k to 5M), extracting 2-D (silhouette- and projection-based) and 3-D (surface-based) features, and then training ensembles of decision trees to predict: a) the 4-D regions on a unit hypersphere into which the unit quaternion that represents the vehicle [Q X, Q Y, Q Z, Q W] is pointing, and, b) the components of that unit quaternion. Results have been quite promising and the tools and simulation environment developed for this application may also be applied to non-cooperative spacecraft operations, Autonomous Hazard Detection and Avoidance (AHDA) for landing craft, terrain mapping, vehicle guidance, path planning and obstacle avoidance.

Human cortical activity evoked by contextual processing in attentional orienting.

PubMed

Zhao, Shuo; Li, Chunlin; Uono, Shota; Yoshimura, Sayaka; Toichi, Motomi

2017-06-07

The ability to assess another person's direction of attention is paramount in social communication, many studies have reported a similar pattern between gaze and arrow cues in attention orienting. Neuroimaging research has also demonstrated no qualitative differences in attention to gaze and arrow cues. However, these studies were implemented under simple experiment conditions. Researchers have highlighted the importance of contextual processing (i.e., the semantic congruence between cue and target) in attentional orienting, showing that attentional orienting by social gaze or arrow cues could be modulated through contextual processing. Here, we examine the neural activity of attentional orienting by gaze and arrow cues in response to contextual processing using functional magnetic resonance imaging. The results demonstrated that the influence of neural activity through contextual processing to attentional orienting occurred under invalid conditions (when the cue and target were incongruent versus congruent) in the ventral frontoparietal network, although we did not identify any differences in the neural substrates of attentional orienting in contextual processing between gaze and arrow cues. These results support behavioural data of attentional orienting modulated by contextual processing based on the neurocognitive architecture.

Using a patterned grating structure to create lipid bilayer platforms insensitive to air bubbles.

PubMed

Han, Chung-Ta; Chao, Ling

2015-01-07

Supported lipid bilayers (SLBs) have been used for various biosensing applications. The bilayer structure enables embedded lipid membrane species to maintain their native orientation, and the two-dimensional fluidity is crucial for numerous biomolecular interactions to occur. The platform integrated with a microfluidic device for reagent transport and exchange has great potential to be applied with surface analytical tools. However, SLBs can easily be destroyed by air bubbles during assay reagent transport and exchange. Here, we created a patterned obstacle grating structured surface in a microfluidic channel to protect SLBs from being destroyed by air bubbles. Unlike all of the previous approaches using chemical modification or adding protection layers to strengthen lipid bilayers, the uniqueness of this approach is that it uses the patterned obstacles to physically trap water above the bilayers to prevent the air-water interface from directly coming into contact with and peeling the bilayers. We showed that our platform with certain grating geometry criteria can provide promising protection to SLBs from air bubbles. The required obstacle distance was found to decrease when we increased the air-bubble movement speed. In addition, the interaction assay results from streptavidin and biotinylated lipids in the confined SLBs suggested that receptors at the SLBs retained the interaction ability after air-bubble treatment. The results showed that the developed SLB platform can preserve both high membrane fluidity and high accessibility to the outside environment, which have never been simultaneously achieved before. Incorporating the built platforms with some surface analytical tools could open the bottleneck of building highly robust in vitro cell-membrane-related bioassays.

A robust close-range photogrammetric target extraction algorithm for size and type variant targets

NASA Astrophysics Data System (ADS)

Nyarko, Kofi; Thomas, Clayton; Torres, Gilbert

2016-05-01

The Photo-G program conducted by Naval Air Systems Command at the Atlantic Test Range in Patuxent River, Maryland, uses photogrammetric analysis of large amounts of real-world imagery to characterize the motion of objects in a 3-D scene. Current approaches involve several independent processes including target acquisition, target identification, 2-D tracking of image features, and 3-D kinematic state estimation. Each process has its own inherent complications and corresponding degrees of both human intervention and computational complexity. One approach being explored for automated target acquisition relies on exploiting the pixel intensity distributions of photogrammetric targets, which tend to be patterns with bimodal intensity distributions. The bimodal distribution partitioning algorithm utilizes this distribution to automatically deconstruct a video frame into regions of interest (ROI) that are merged and expanded to target boundaries, from which ROI centroids are extracted to mark target acquisition points. This process has proved to be scale, position and orientation invariant, as well as fairly insensitive to global uniform intensity disparities.

Feature reliability determines specificity and transfer of perceptual learning in orientation search.

PubMed

Yashar, Amit; Denison, Rachel N

2017-12-01

Training can modify the visual system to produce a substantial improvement on perceptual tasks and therefore has applications for treating visual deficits. Visual perceptual learning (VPL) is often specific to the trained feature, which gives insight into processes underlying brain plasticity, but limits VPL's effectiveness in rehabilitation. Under what circumstances VPL transfers to untrained stimuli is poorly understood. Here we report a qualitatively new phenomenon: intrinsic variation in the representation of features determines the transfer of VPL. Orientations around cardinal are represented more reliably than orientations around oblique in V1, which has been linked to behavioral consequences such as visual search asymmetries. We studied VPL for visual search of near-cardinal or oblique targets among distractors of the other orientation while controlling for other display and task attributes, including task precision, task difficulty, and stimulus exposure. Learning was the same in all training conditions; however, transfer depended on the orientation of the target, with full transfer of learning from near-cardinal to oblique targets but not the reverse. To evaluate the idea that representational reliability was the key difference between the orientations in determining VPL transfer, we created a model that combined orientation-dependent reliability, improvement of reliability with learning, and an optimal search strategy. Modeling suggested that not only search asymmetries but also the asymmetric transfer of VPL depended on preexisting differences between the reliability of near-cardinal and oblique representations. Transfer asymmetries in model behavior also depended on having different learning rates for targets and distractors, such that greater learning for low-reliability distractors facilitated transfer. These findings suggest that training on sensory features with intrinsically low reliability may maximize the generalizability of learning in complex visual environments.

Retrieving self-vocalized information: An event-related potential (ERP) study on the effect of retrieval orientation.

PubMed

Rosburg, Timm; Johansson, Mikael; Sprondel, Volker; Mecklinger, Axel

2014-11-18

Retrieval orientation refers to a pre-retrieval process and conceptualizes the specific form of processing that is applied to a retrieval cue. In the current event-related potential (ERP) study, we sought to find evidence for an involvement of the auditory cortex when subjects attempt to retrieve vocalized information, and hypothesized that adopting retrieval orientation would be beneficial for retrieval accuracy. During study, participants saw object words that they subsequently vocalized or visually imagined. At test, participants had to identify object names of one study condition as targets and to reject object names of the second condition together with new items. Target category switched after half of the test trials. Behaviorally, participants responded less accurately and more slowly to targets of the vocalize condition than to targets of the imagine condition. ERPs to new items varied at a single left electrode (T7) between 500 and 800ms, indicating a moderate retrieval orientation effect in the subject group as a whole. However, whereas the effect was strongly pronounced in participants with high retrieval accuracy, it was absent in participants with low retrieval accuracy. A current source density (CSD) mapping of the retrieval orientation effect indicated a source over left temporal regions. Independently from retrieval accuracy, the ERP retrieval orientation effect was surprisingly also modulated by test order. Findings are suggestive for an involvement of the auditory cortex in retrieval attempts of vocalized information and confirm that adopting retrieval orientation is potentially beneficial for retrieval accuracy. The effects of test order on retrieval-related processes might reflect a stronger focus on the newness of items in the more difficult test condition when participants started with this condition. Copyright © 2014 Elsevier Inc. All rights reserved.

Feature reliability determines specificity and transfer of perceptual learning in orientation search

PubMed Central

2017-01-01

Training can modify the visual system to produce a substantial improvement on perceptual tasks and therefore has applications for treating visual deficits. Visual perceptual learning (VPL) is often specific to the trained feature, which gives insight into processes underlying brain plasticity, but limits VPL’s effectiveness in rehabilitation. Under what circumstances VPL transfers to untrained stimuli is poorly understood. Here we report a qualitatively new phenomenon: intrinsic variation in the representation of features determines the transfer of VPL. Orientations around cardinal are represented more reliably than orientations around oblique in V1, which has been linked to behavioral consequences such as visual search asymmetries. We studied VPL for visual search of near-cardinal or oblique targets among distractors of the other orientation while controlling for other display and task attributes, including task precision, task difficulty, and stimulus exposure. Learning was the same in all training conditions; however, transfer depended on the orientation of the target, with full transfer of learning from near-cardinal to oblique targets but not the reverse. To evaluate the idea that representational reliability was the key difference between the orientations in determining VPL transfer, we created a model that combined orientation-dependent reliability, improvement of reliability with learning, and an optimal search strategy. Modeling suggested that not only search asymmetries but also the asymmetric transfer of VPL depended on preexisting differences between the reliability of near-cardinal and oblique representations. Transfer asymmetries in model behavior also depended on having different learning rates for targets and distractors, such that greater learning for low-reliability distractors facilitated transfer. These findings suggest that training on sensory features with intrinsically low reliability may maximize the generalizability of learning in complex visual environments. PMID:29240813

Frontal-parietal synchrony in elderly EEG for visual search.

PubMed

Phillips, Steven; Takeda, Yuji

2010-01-01

Aging involves selective changes in attentional control. However, its precise effect on visual attention is difficult to discern from behavioural studies alone. In this paper, we employ a recently developed phase-locking measure of synchrony as an indicator of top-down/bottom-up control of attention to assess attentional control in the elderly. Fourteen participants (63-74 years) searched for a target item (coloured, oriented rectangular bar) among a display set of distractors. For the feature search condition, where none of the distractors shared a feature with the target, search time did not increase with display set size (two, or four items). For the conjunctive search condition, where each distractor shared either a colour or orientation feature with the target, search time increased with display size. Phase-locking analysis revealed a significant increase in high gamma-band (36-56 Hz) synchrony indicating greater bottom-up control for feature than conjunctive search. In view of our earlier study on younger (21-32 years) adults (Phillips and Takeda, 2009), these results suggest that older participants are more likely to use bottom-up control of attention, possibly triggered by their greater susceptibility to attentional capture, than younger participants. Copyright (c) 2009 Elsevier B.V. All rights reserved.

Improving the Quality of Learning: A Framework for Target-Oriented Curriculum Renewal in Hong Kong. Revised.

ERIC Educational Resources Information Center

Clark, John L.; And Others

This document sets out a "Framework" to underpin the development and ongoing renewal of the school curriculum in Hong Kong. It also indicates the bases on which the Framework is developed. The Framework forms the foundation of Hong Kong's Target-Oriented Curriculum (TOC) initiative and provides a useful reference for curriculum…

A tool for cost-effectiveness analysis of field scale sediment-bound phosphorus mitigation measures and application to analysis of spatial and temporal targeting in the Lunan Water catchment, Scotland.

PubMed

Vinten, Andy; Sample, James; Ibiyemi, Adekunle; Abdul-Salam, Yakubu; Stutter, Marc

2017-05-15

The cost-effectiveness of six edge-of-field measures for mitigating diffuse pollution from sediment bound phosphorus (P) runoff from temperate arable farmland is analysed at catchment/field scales. These measures were: buffer strips, permanent grassland in the lowest 7% of arable fields, dry detention bunds, wetlands, and temporary barriers such as sediment fences. Baseline field P export was estimated using export coefficients (low risk crops) or a modified Universal Soil Loss Equation (high risk crops). The impact of measures was estimated using simple equations. Costs were estimated from gross margin losses or local data on grants. We used a net cost:benefit (NCB) factor to normalise the costs and impacts of each measure over time. Costs minimisation for target impact was done using PuLP, a linear programming module for Python, across 1634 riparian and non-riparian fields in the Lunan Water, a mixed arable catchment in Eastern Scotland. With all measures in place, average cost-effectiveness increases from £9 to £48/kg P as target P mitigation increases from 500 to 2500kg P across the catchment. Costs increase significantly when the measures available are restricted only to those currently eligible for government grants (buffers, bunds and wetlands). The assumed orientation of the average field slope makes a strong difference to the potential for storage of water by bunds and overall cost-effectiveness, but the non-funded measures can substitute for the extra expense incurred by bunds, where the slope orientation is not suitable. Economic discounting over time of impacts and costs of measures favours those measures, such as sediment fences, which are strongly targeted both spatially and temporally. This tool could be a useful guide for dialogue with land users about the potential fields to target for mitigation to achieve catchment targets. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Altering the orientation of a fused protein to the RNA-binding ribosomal protein L7Ae and its derivatives through circular permutation.

PubMed

Ohuchi, Shoji J; Sagawa, Fumihiko; Sakamoto, Taiichi; Inoue, Tan

2015-10-23

RNA-protein complexes (RNPs) are useful for constructing functional nano-objects because a variety of functional proteins can be displayed on a designed RNA scaffold. Here, we report circular permutations of an RNA-binding protein L7Ae based on the three-dimensional structure information to alter the orientation of the displayed proteins on the RNA scaffold. An electrophoretic mobility shift assay and atomic force microscopy (AFM) analysis revealed that most of the designed circular permutants formed an RNP nano-object. Moreover, the alteration of the enhanced green fluorescent protein (EGFP) orientation was confirmed with AFM by employing EGFP on the L7Ae permutant on the RNA. The results demonstrate that targeted fine-tuning of the stereo-specific fixation of a protein on a protein-binding RNA is feasible by using the circular permutation technique. Copyright © 2015 Elsevier Inc. All rights reserved.

Altering the orientation of a fused protein to the RNA-binding ribosomal protein L7Ae and its derivatives through circular permutation

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

Ohuchi, Shoji J.; Sagawa, Fumihiko; Sakamoto, Taiichi

RNA-protein complexes (RNPs) are useful for constructing functional nano-objects because a variety of functional proteins can be displayed on a designed RNA scaffold. Here, we report circular permutations of an RNA-binding protein L7Ae based on the three-dimensional structure information to alter the orientation of the displayed proteins on the RNA scaffold. An electrophoretic mobility shift assay and atomic force microscopy (AFM) analysis revealed that most of the designed circular permutants formed an RNP nano-object. Moreover, the alteration of the enhanced green fluorescent protein (EGFP) orientation was confirmed with AFM by employing EGFP on the L7Ae permutant on the RNA. Themore » results demonstrate that targeted fine-tuning of the stereo-specific fixation of a protein on a protein-binding RNA is feasible by using the circular permutation technique.« less

Body shape ideals across gender, sexual orientation, socioeconomic status, race, and age in personal advertisements.

PubMed

Epel, E S; Spanakos, A; Kasl-Godley, J; Brownell, K D

1996-04-01

To assess body shape ideals across gender, sexual orientation, race, socio-economic status, and age, An analysis of personal advertisements was conducted across seven different publications which targeted the groups of interest. Women advertised body weight much less often than men, and lesbians reported body shape descriptors significantly less often than heterosexual women. Gay men and African-American men described their body shape significantly more often than did other groups. However, their reported body mass indices (BMI) were significantly different-African-American men reported a higher BMI, and gay men a lower BMI, than Euro-American heterosexual men. Race and sexual orientation may influence the importance of size of body shape ideals for men. For women, however, their advertised weights conformed to the thin ideal across all groups surveyed. Gender roles affecting body shape ideals and mate attraction are discussed.

Ligand-based targeted therapy: a novel strategy for hepatocellular carcinoma

PubMed Central

Li, Min; Zhang, Weiyue; Wang, Birong; Gao, Yang; Song, Zifang; Zheng, Qi Chang

2016-01-01

Hepatocellular carcinoma (HCC) is the most common primary liver cancer with high morbidity and mortality worldwide. Chemotherapy is recommended to patients with intermediate or advanced stage cancer. However, the conventional chemotherapy yields low desired response rates due to multidrug resistance, fast clearance rate, nonspecific delivery, severe side effects, low drug concentration in cancer cells, and so on. Nanoparticle-mediated targeted drug delivery system can surmount the aforementioned obstacles through enhanced permeability and retention effect and active targeting as a novel approach of therapeutics for HCC in recent years. The active targeting is triggered by ligands on the delivery system, which recognize with and internalize into hepatoma cells with high specificity and efficiency. This review focuses on the latest targeted delivery systems for HCC and summarizes the ligands that can enhance the capacity of active targeting, to provide some insight into future research in nanomedicine for HCC. PMID:27920520

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.

Virtual local target method for avoiding local minimum in potential field based robot navigation.

PubMed

Zou, Xi-Yong; Zhu, Jing

2003-01-01

A novel robot navigation algorithm with global path generation capability is presented. Local minimum is a most intractable but is an encountered frequently problem in potential field based robot navigation. Through appointing appropriately some virtual local targets on the journey, it can be solved effectively. The key concept employed in this algorithm are the rules that govern when and how to appoint these virtual local targets. When the robot finds itself in danger of local minimum, a virtual local target is appointed to replace the global goal temporarily according to the rules. After the virtual target is reached, the robot continues on its journey by heading towards the global goal. The algorithm prevents the robot from running into local minima anymore. Simulation results showed that it is very effective in complex obstacle environments.

A path-oriented knowledge representation system: Defusing the combinatorial system

NASA Technical Reports Server (NTRS)

Karamouzis, Stamos T.; Barry, John S.; Smith, Steven L.; Feyock, Stefan

1995-01-01

LIMAP is a programming system oriented toward efficient information manipulation over fixed finite domains, and quantification over paths and predicates. A generalization of Warshall's Algorithm to precompute paths in a sparse matrix representation of semantic nets is employed to allow questions involving paths between components to be posed and answered easily. LIMAP's ability to cache all paths between two components in a matrix cell proved to be a computational obstacle, however, when the semantic net grew to realistic size. The present paper describes a means of mitigating this combinatorial explosion to an extent that makes the use of the LIMAP representation feasible for problems of significant size. The technique we describe radically reduces the size of the search space in which LIMAP must operate; semantic nets of more than 500 nodes have been attacked successfully. Furthermore, it appears that the procedure described is applicable not only to LIMAP, but to a number of other combinatorially explosive search space problems found in AI as well.

I(CES)-cubes: a modular self-reconfigurable bipartite robotic system

NASA Astrophysics Data System (ADS)

Unsal, Cem; Kiliccote, Han; Khosla, Pradeep K.

1999-08-01

In this manuscript, we introduce I(CES)-Cubes, a class of 3D modular robotic system that is capable of reconfiguring itself in order to adapt to its environment. This is a bipartite system, i.e. a collection of (i) active elements capable of actuation, and (ii) passive elements acting as connectors between actuated elements. Active elements, called links, are 3-DOF manipulators that are capable of attaching/detaching themselves to/from the passive elements. The cubes can then be positioned and oriented using links, which are independent mechatronic elements. Self- reconfiguration property enables the system to performed locomotion tasks over difficult terrain. For example, the system would be capable of moving over obstacles and climbing stairs. These task are performed by positing and orienting cubes and links to form a 3D network with required shape and position. This paper describes the design of the passive and active elements, the attachment mechanics, and several reconfiguration scenarios. Specifics of the hardware implementation and result of experiments with current prototypes are also given.

Academic Incentives for Faculty Participation in Community-based Participatory Research

PubMed Central

Nyden, Philip

2003-01-01

Recognizing the need to overcome the obstacles of traditional university- and discipline-oriented research approaches, a variety of incentives to promote community-based participatory research (CBPR) are presented. Experiences of existing CBPR researchers are used in outlining how this methodological approach can appeal to faculty: the common ground shared by faculty and community leaders in challenging the status quo; opportunities to have an impact on local, regional, and national policy; and opening doors for new research and funding opportunities. Strategies for promoting CBPR in universities are provided in getting CBPR started, changing institutional practices currently inhibiting CBPR, and institutionalizing CBPR. Among the specific strategies are: development of faculty research networks; team approaches to CBPR; mentoring faculty and students; using existing national CBPR networks; modifying tenure and promotion guidelines; development of appropriate measures of CBPR scholarship; earmarking university resources to support CBPR; using Institutional Review Boards to promote CBPR; making CBPR-oriented faculty appointments; and creating CBPR centers. PMID:12848841

Ethical and Diversity Challenges in Ecologically Sensitive Systems-Oriented Interventions

PubMed Central

Jason, Leonard A.

2016-01-01

This article discusses ethical and diversity challenges involved in implementing ecologically sensitive, systems-oriented research. These issues are considered with reference to a series of community-based interventions dealing with stigma and chronic illness, recovery from substance-use disorders, and prevention of tobacco use. Each of these ecological interventions incorporates a systems approach, which allows an understanding of how individuals affect and are influenced by their social environments. In addition, issues of diversity with respect to underrepresented and marginalized groups are considered, including overcoming obstacles to gaining access to resources and promoting increased opportunities and empowerment. Throughout, the central importance of developing relationships with key gatekeepers and stakeholders, as well as timely and effective communications with various coalition members, is highlighted. By bringing into the research and policy process diverse citizen/participant suggestions and input regarding the need for, or design and implementation of ecologically and systems-based interventions, researchers can build collaborative relationships that fuel trust and partnerships, leading to more ethically responsible research. PMID:26618968

Why is it taking so long for healthcare professional education to become relevant and effective? What can be done?

PubMed

Guilbert, Jean-Jacques

2014-01-01

For about a half century the World Health Organization (WHO), supported by the literature in the field of health personnel education, has argued for the benefits of a learner-centered and community-oriented approach to professional education. Nevertheless, change has not happened in the vast majority of schools and countries. This paper describes the obstacles and constraints to change in health professional education: Obsolete administrative rules, the low profile of public health, the lack of real decision power of faculty, a dearth of faculty trained in the field of education, the arbitrary separation between so-called basic sciences and clinical practice, the disciplinary orientation of learning objectives, a lack of explicit definition of desirable professional competencies, and, above all, too little value placed on the evaluation of educational programs. The recent literature continues to argue for change but action does not follow. Only very few training institutions currently put newer approaches into practice. The university culture remains an environment that stifles change.

An Energy-Efficient Target-Tracking Strategy for Mobile Sensor Networks.

PubMed

Mahboubi, Hamid; Masoudimansour, Walid; Aghdam, Amir G; Sayrafian-Pour, Kamran

2017-02-01

In this paper, an energy-efficient strategy is proposed for tracking a moving target in an environment with obstacles, using a network of mobile sensors. Typically, the most dominant sources of energy consumption in a mobile sensor network are sensing, communication, and movement. The proposed algorithm first divides the field into a grid of sufficiently small cells. The grid is then represented by a graph whose edges are properly weighted to reflect the energy consumption of sensors. The proposed technique searches for near-optimal locations for the sensors in different time instants to route information from the target to destination, using a shortest path algorithm. Simulations confirm the efficacy of the proposed algorithm.

Towards the discovery of drug-like RNA ligands?

PubMed

Foloppe, Nicolas; Matassova, Natalia; Aboul-Ela, Fareed

2006-11-01

Targeting RNA with small molecule drugs is an area of great potential for therapeutic treatment of infections and possibly genetic and autoimmune diseases. However, a mature set of precedents and established methodology is lacking. The physicochemical properties of RNA raise specific issues and obstacles to development, and contribute to explain the distinct characteristics of natural RNA ligands, including antibiotics. Yet, RNA-targeting strategies are being implemented to reinvigorate antibacterial discovery by using the ribosomal X-ray structures to modify known antibiotics. To exploit further these structures, we suggest the use of existing protein kinase-directed libraries of drug-like compounds to target the A-site of the bacterial ribosome, on the basis of a specific structural hypothesis.

Diversity-Oriented Synthesis of Coumarin-Linked Benzimidazoles via a One-Pot, Three-Step, Intramolecular Knoevenagel Cyclization.

PubMed

Yao, Po-Hsin Eric; Kumar, Sunil; Liu, Yu-Li; Fang, Chiu-Ping; Liu, Chia-Chen; Sun, Chung-Ming

2017-04-10

Diversity-oriented synthesis of coumarin-linked benzimidazoles from N-(2-aminophenyl)-2-cyanoacetamide was achieved via a one-pot, three-step sequential reaction in excellent yields. In situ intramolecular cyclization of the cyanoacetamide afforded benzimidazoles which subsequently underwent a Knoevenagel condensation of the 2-cyanomethylbenzimidazoles with salicylaldehydes promoted by triethylamine to reach the target compounds. An important intermediate, 2-(2-imino-2H-chromen-3-yl)-1H-benzimidazole was characterized by X-ray analysis and further hydrolyzed to 2-(coumarin-3-yl)benzimidazole in acidic condition. Among the synthesized compounds, some were found to be promising inhibitors of porcine kidney d-amino acid oxidase (pkDAO).

The Demand for and the Provision of Early Childhood Services since 2000: Policies and Strategies

ERIC Educational Resources Information Center

Shaeffer, Sheldon

2016-01-01

Since the Millennium Development Goals and Education for All targets were proclaimed in 2000, countries have made considerable progress in enhancing the well-being of young children. But many young children--including 78% in the Arab states and over 80% in sub-Saharan Africa--still have no access to this education. Obstacles to increasing the…

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'…

Goal-oriented sensitivity analysis for lattice kinetic Monte Carlo simulations

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

Arampatzis, Georgios, E-mail: garab@math.uoc.gr; Department of Mathematics and Statistics, University of Massachusetts, Amherst, Massachusetts 01003; Katsoulakis, Markos A., E-mail: markos@math.umass.edu

2014-03-28

In this paper we propose a new class of coupling methods for the sensitivity analysis of high dimensional stochastic systems and in particular for lattice Kinetic Monte Carlo (KMC). Sensitivity analysis for stochastic systems is typically based on approximating continuous derivatives with respect to model parameters by the mean value of samples from a finite difference scheme. Instead of using independent samples the proposed algorithm reduces the variance of the estimator by developing a strongly correlated-“coupled”- stochastic process for both the perturbed and unperturbed stochastic processes, defined in a common state space. The novelty of our construction is that themore » new coupled process depends on the targeted observables, e.g., coverage, Hamiltonian, spatial correlations, surface roughness, etc., hence we refer to the proposed method as goal-oriented sensitivity analysis. In particular, the rates of the coupled Continuous Time Markov Chain are obtained as solutions to a goal-oriented optimization problem, depending on the observable of interest, by considering the minimization functional of the corresponding variance. We show that this functional can be used as a diagnostic tool for the design and evaluation of different classes of couplings. Furthermore, the resulting KMC sensitivity algorithm has an easy implementation that is based on the Bortz–Kalos–Lebowitz algorithm's philosophy, where events are divided in classes depending on level sets of the observable of interest. Finally, we demonstrate in several examples including adsorption, desorption, and diffusion Kinetic Monte Carlo that for the same confidence interval and observable, the proposed goal-oriented algorithm can be two orders of magnitude faster than existing coupling algorithms for spatial KMC such as the Common Random Number approach. We also provide a complete implementation of the proposed sensitivity analysis algorithms, including various spatial KMC examples, in a supplementary MATLAB source code.« less

A New Technique for Compensating Joint Limits in a Robot Manipulator

NASA Technical Reports Server (NTRS)

Litt, Jonathan; Hickman, Andre; Guo, Ten-Huei

1996-01-01

A new robust, optimal, adaptive technique for compensating rate and position limits in the joints of a six degree-of-freedom elbow manipulator is presented. In this new algorithm, the unmet demand as a result of actuator saturation is redistributed among the remaining unsaturated joints. The scheme is used to compensate for inadequate path planning, problems such as joint limiting, joint freezing, or even obstacle avoidance, where a desired position and orientation are not attainable due to an unrealizable joint command. Once a joint encounters a limit, supplemental commands are sent to other joints to best track, according to a selected criterion, the desired trajectory.

Finding Out Critical Points For Real-Time Path Planning

NASA Astrophysics Data System (ADS)

Chen, Wei

1989-03-01

Path planning for a mobile robot is a classic topic, but the path planning under real-time environment is a different issue. The system sources including sampling time, processing time, processes communicating time, and memory space are very limited for this type of application. This paper presents a method which abstracts the world representation from the sensory data and makes the decision as to which point will be a potentially critical point to span the world map by using incomplete knowledge about physical world and heuristic rule. Without any previous knowledge or map of the workspace, the robot will determine the world map by roving through the workspace. The computational complexity for building and searching such a map is not more than O( n2 ) The find-path problem is well-known in robotics. Given an object with an initial location and orientation, a goal location and orientation, and a set of obstacles located in space, the problem is to find a continuous path for the object from the initial position to the goal position which avoids collisions with obstacles along the way. There are a lot of methods to find a collision-free path in given environment. Techniques for solving this problem can be classified into three approaches: 1) the configuration space approach [1],[2],[3] which represents the polygonal obstacles by vertices in a graph. The idea is to determine those parts of the free space which a reference point of the moving object can occupy without colliding with any obstacles. A path is then found for the reference point through this truly free space. Dealing with rotations turns out to be a major difficulty with the approach, requiring complex geometric algorithms which are computationally expensive. 2) the direct representation of the free space using basic shape primitives such as convex polygons [4] and overlapping generalized cones [5]. 3) the combination of technique 1 and 2 [6] by which the space is divided into the primary convex region, overlap region and obstacle region, then obstacle boundaries with attribute values are represented by the vertices of the hypergraph. The primary convex region and overlap region are represented by hyperedges, the centroids of overlap form the critical points. The difficulty is generating segment graph and estimating of minimum path width. The all techniques mentioned above need previous knowledge about the world to make path planning and the computational cost is not low. They are not available in an unknow and uncertain environment. Due to limited system resources such as CPU time, memory size and knowledge about the special application in an intelligent system (such as mobile robot), it is necessary to use algorithms that provide the good decision which is feasible with the available resources in real time rather than the best answer that could be achieved in unlimited time with unlimited resources. A real-time path planner should meet following requirements: - Quickly abstract the representation of the world from the sensory data without any previous knowledge about the robot environment. - Easily update the world model to spell out the global-path map and to reflect changes in the robot environment. - Must make a decision of where the robot must go and which direction the range sensor should point to in real time with limited resources. The method presented here assumes that the data from range sensors has been processed by signal process unite. The path planner will guide the scan of range sensor, find critical points, make decision where the robot should go and which point is poten- tial critical point, generate the path map and monitor the robot moves to the given point. The program runs recursively until the goal is reached or the whole workspace is roved through.

Orientation/Time Management Skill Training Lesson: Development and Evaluation

DTIC Science & Technology

1979-07-01

instructional environment. This Orientation/ Time Management lesson provides students with appropriate role models for increasing acceptance of their...time savings can be obtained by a combination of this type of orientation and time management skill training with a computer-based progress targeting

Perception for mobile robot navigation: A survey of the state of the art

NASA Technical Reports Server (NTRS)

Kortenkamp, David

1994-01-01

In order for mobile robots to navigate safely in unmapped and dynamic environments they must perceive their environment and decide on actions based on those perceptions. There are many different sensing modalities that can be used for mobile robot perception; the two most popular are ultrasonic sonar sensors and vision sensors. This paper examines the state-of-the-art in sensory-based mobile robot navigation. The first issue in mobile robot navigation is safety. This paper summarizes several competing sonar-based obstacle avoidance techniques and compares them. Another issue in mobile robot navigation is determining the robot's position and orientation (sometimes called the robot's pose) in the environment. This paper examines several different classes of vision-based approaches to pose determination. One class of approaches uses detailed, a prior models of the robot's environment. Another class of approaches triangulates using fixed, artificial landmarks. A third class of approaches builds maps using natural landmarks. Example implementations from each of these three classes are described and compared. Finally, the paper presents a completely implemented mobile robot system that integrates sonar-based obstacle avoidance with vision-based pose determination to perform a simple task.

Mechanical diffraction in a sand-specialist snake

NASA Astrophysics Data System (ADS)

Schiebel, Perrin E.; Rieser, Jennifer M.; Hubbard, Alex M.; Chen, Lillian; Goldman, Daniel I.

Limbless locomotors such as snakes move by pressing the trunk against terrain heterogeneities. Our laboratory studies of the desert-dwelling Mojave Shovel-nosed snake (C. occipitalis, 40cm long, N=9) reveal that these animals use a stereotyped sinusoidal traveling wave of curvature. However, this snake also encounters rigid obstacles in its natural environment, and the tradeoff between using a cyclic, shape controlled gait versus one which changes shape in response to the terrain is not well understood. We challenged individuals to move across a model deformable substrate (carpet) through a row of 6.4 mm diameter force-sensitive pegs, a model of obstacles such as grass, oriented perpendicular to the direction of motion. Instead of forward-directed reaction forces, reaction forces generated by the pegs were more often perpendicular to the direction of motion. Distributions of post-peg travel angles displayed preferred directions revealing a diffraction-like pattern with a central peak at zero and symmetric peaks at 193 ° and 415 °. We observed similar dynamics in a robotic snake using shape-based control. This suggests that this sand-specialist snake adheres to its preferred waveform as opposed to changing in response to heterogeneity.

Lateralization of spatial rather than temporal attention underlies the left hemifield advantage in rapid serial visual presentation.

PubMed

Asanowicz, Dariusz; Kruse, Lena; Śmigasiewicz, Kamila; Verleger, Rolf

2017-11-01

In bilateral rapid serial visual presentation (RSVP), the second of two targets, T1 and T2, is better identified in the left visual field (LVF) than in the right visual field (RVF). This LVF advantage may reflect hemispheric asymmetry in temporal attention or/and in spatial orienting of attention. Participants performed two tasks: the "standard" bilateral RSVP task (Exp.1) and its unilateral variant (Exp.1 & 2). In the bilateral task, spatial location was uncertain, thus target identification involved stimulus-driven spatial orienting. In the unilateral task, the targets were presented block-wise in the LVF or RVF only, such that no spatial orienting was needed for target identification. Temporal attention was manipulated in both tasks by varying the T1-T2 lag. The results showed that the LVF advantage disappeared when involvement of stimulus-driven spatial orienting was eliminated, whereas the manipulation of temporal attention had no effect on the asymmetry. In conclusion, the results do not support the hypothesis of hemispheric asymmetry in temporal attention, and provide further evidence that the LVF advantage reflects right hemisphere predominance in stimulus-driven orienting of spatial attention. These conclusions fit evidence that temporal attention is implemented by bilateral parietal areas and spatial attention by the right-lateralized ventral frontoparietal network. Copyright © 2017 Elsevier Inc. All rights reserved.

Taiwan Regulation of Biobanks.

PubMed

Fan, Chien-Te; Hung, Tzu-Hsun; Yeh, Chan-Kun

2015-01-01

This paper introduces legal framework and governance structure in relation to the management and development of biobanks in Taiwan. At first, we briefly describe Taiwan's population, political system and health care system. Secondly, this research introduces biobanking framework of Taiwan including 25 biobanks established with the approval of the Ministry of Health and Welfare. In those biobanks, "Taiwan Biobank" is the first and the largest government-supported biobank which comprises population-based cohort study and disease- oriented study. Since the collection of information, data, and biological specimen of biobanks often involve highly sensitive personal information, in the legal framework of Taiwan, there is a specific regulation, "Human Biobank Management Act" (HBMA), which plays an important role in regulating biobanks in Taiwan. HBMA, the Personal Information Act and other regulations constitute a comprehensive legal and regulatory privacy framework of biobanks. Through the introduction and analysis of the current legal framework applicable to biobanks, we found that there are several challenges that need to be solved appropriately that involve duplicate review systems, the obstacles in the international collaboration, and data sharing between biobanks in Taiwan. © 2015 American Society of Law, Medicine & Ethics, Inc.

Aggregation-induced emission in lamellar solids of colloidal perovskite quantum wells

PubMed Central

Jagielski, Jakub; Kumar, Sudhir; Wang, Mingchao; Scullion, Declan; Lawrence, Robert; Li, Yen-Ting; Yakunin, Sergii; Tian, Tian; Kovalenko, Maksym V.; Chiu, Yu-Cheng; Santos, Elton J. G.; Lin, Shangchao; Shih, Chih-Jen

2017-01-01

The outstanding excitonic properties, including photoluminescence quantum yield (ηPL), of individual, quantum-confined semiconductor nanoparticles are often significantly quenched upon aggregation, representing the main obstacle toward scalable photonic devices. We report aggregation-induced emission phenomena in lamellar solids containing layer-controlled colloidal quantum wells (QWs) of hybrid organic-inorganic lead bromide perovskites, resulting in anomalously high solid-state ηPL of up to 94%. Upon forming the QW solids, we observe an inverse correlation between exciton lifetime and ηPL, distinct from that in typical quantum dot solid systems. Our multiscale theoretical analysis reveals that, in a lamellar solid, the collective motion of the surface organic cations is more restricted to orient along the [100] direction, thereby inducing a more direct bandgap that facilitates radiative recombination. Using the QW solids, we demonstrate ultrapure green emission by completely downconverting a blue gallium nitride light-emitting diode at room temperature, with a luminous efficacy higher than 90 lumen W−1 at 5000 cd m−2, which has never been reached in any nanomaterial assemblies by far. PMID:29282451

Implications of Tumor Heterogeneity for Precision Medicine

NASA Astrophysics Data System (ADS)

Jeraj, Robert

Medical physics is intimately connected with medicine, and is progressing along a similar path. General trend of medicine, particularly oncology, towards personalized treatment gave rise to precision medicine, which addresses the highly complex nature of disease. However, there are severe obstacles to overcome. For example, cancers evolve in time to become harder targets to treat. Understanding treatment resistance, and its development, often connected with the highly heterogeneous nature of the disease, is another key obstacle. Use of multi-modality imaging techniques such as molecular imaging is one of the solutions that medical physics can offer. Examples from clinical trials utilizing advanced molecular imaging, highlighting intra-tumor and inter-tumor heterogeneity will be presented. New understanding of cancer treatment response dynamics will be outlined. Potential for improved patient treatment designs steaming from these novel insights will be discussed.

Fracture network topology and characterization of structural permeability

NASA Astrophysics Data System (ADS)

Hansberry, Rowan; King, Rosalind; Holford, Simon

2017-04-01

There are two fundamental requirements for successful geothermal development: elevated temperatures at accessible depths, and a reservoir from which fluids can be extracted. The Australian geothermal sector has successfully targeted shallow heat, however, due in part to the inherent complexity of targeting permeability, obtaining adequate flow rates for commercial production has been problematic. Deep sedimentary aquifers are unlikely to be viable geothermal resources due to the effects of diagenetic mineral growth on rock permeability. Therefore, it is likely structural permeability targets, exploiting natural or induced fracture networks will provide the primary means for fluid flow in geothermal, as well as unconventional gas, reservoirs. Recent research has focused on the pattern and generation of crustal stresses across Australia, while less is known about the resultant networks of faults, joints, and veins that can constitute interconnected sub-surface permeability pathways. The ability of a fracture to transmit fluid is controlled by the orientation and magnitude of the in-situ stress field that acts on the fracture walls, rock strength, and pore pressure, as well as fracture properties such as aperture, orientation, and roughness. Understanding the distribution, orientation and character of fractures is key to predicting structural permeability. This project focuses on extensive mapping of fractures over various scales in four key Australian basins (Cooper, Otway, Surat and Perth) with the potential to host geothermal resources. Seismic attribute analysis is used in concert with image logs from petroleum wells, and field mapping to identify fracture networks that are usually not resolved in traditional seismic interpretation. We use fracture network topology to provide scale-invariant characterisation of fracture networks from multiple data sources to assess similarity between data sources, and fracture network connectivity. These results are compared with other permeability indicators such as drilling fluid losses, and pore pressure measurements. Initial work with these techniques has led to new developments in our ability to image subsurface faults and fractures at a variety of scales from independent datasets. We establish a strong relationship between features identified using seismic attribute analysis and interpreted natural fractures. However, care must be taken to use these methods in a case-by-case basis, as controls on fracture distribution and orientation can vary significantly with both regional and local influences. These results outline and effective method by which structural permeability can be assessed with existing petroleum datasets. However, unlike the broad stress field, mapping fracture orientation and characteristics within the Australian Continent is complicated as the distribution, geometry, areal extent and connectivity of fracture networks can vary significantly.

Estimation of distal arm joint angles from EMG and shoulder orientation for transhumeral prostheses.

PubMed

Akhtar, Aadeel; Aghasadeghi, Navid; Hargrove, Levi; Bretl, Timothy

2017-08-01

In this paper, we quantify the extent to which shoulder orientation, upper-arm electromyography (EMG), and forearm EMG are predictors of distal arm joint angles during reaching in eight subjects without disability as well as three subjects with a unilateral transhumeral amputation and targeted reinnervation. Prior studies have shown that shoulder orientation and upper-arm EMG, taken separately, are predictors of both elbow flexion/extension and forearm pronation/supination. We show that, for eight subjects without disability, shoulder orientation and upper-arm EMG together are a significantly better predictor of both elbow flexion/extension during unilateral (R 2 =0.72) and mirrored bilateral (R 2 =0.72) reaches and of forearm pronation/supination during unilateral (R 2 =0.77) and mirrored bilateral (R 2 =0.70) reaches. We also show that adding forearm EMG further improves the prediction of forearm pronation/supination during unilateral (R 2 =0.82) and mirrored bilateral (R 2 =0.75) reaches. In principle, these results provide the basis for choosing inputs for control of transhumeral prostheses, both by subjects with targeted motor reinnervation (when forearm EMG is available) and by subjects without target motor reinnervation (when forearm EMG is not available). In particular, we confirm that shoulder orientation and upper-arm EMG together best predict elbow flexion/extension (R 2 =0.72) for three subjects with unilateral transhumeral amputations and targeted motor reinnervation. However, shoulder orientation alone best predicts forearm pronation/supination (R 2 =0.88) for these subjects, a contradictory result that merits further study. Copyright © 2017 Elsevier Ltd. All rights reserved.

Pattern drilling exploration: Optimum pattern types and hole spacings when searching for elliptical shaped targets

USGS Publications Warehouse

Drew, L.J.

1979-01-01

In this study the selection of the optimum type of drilling pattern to be used when exploring for elliptical shaped targets is examined. The rhombic pattern is optimal when the targets are known to have a preferred orientation. Situations can also be found where a rectangular pattern is as efficient as the rhombic pattern. A triangular or square drilling pattern should be used when the orientations of the targets are unknown. The way in which the optimum hole spacing varies as a function of (1) the cost of drilling, (2) the value of the targets, (3) the shape of the targets, (4) the target occurrence probabilities was determined for several examples. Bayes' rule was used to show how target occurrence probabilities can be revised within a multistage pattern drilling scheme. ?? 1979 Plenum Publishing Corporation.

Role of Insulin-Like Growth Factor-1 Signaling Pathway in Cisplatin-Resistant Lung Cancer Cells

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

Sun Yunguang; Zheng Siyuan; Torossian, Artour

2012-03-01

Purpose: The development of drug-resistant phenotypes has been a major obstacle to cisplatin use in non-small-cell lung cancer. We aimed to identify some of the molecular mechanisms that underlie cisplatin resistance using microarray expression analysis. Methods and Materials: H460 cells were treated with cisplatin. The differences between cisplatin-resistant lung cancer cells and parental H460 cells were studied using Western blot, MTS, and clonogenic assays, in vivo tumor implantation, and microarray analysis. The cisplatin-R cells were treated with human recombinant insulin-like growth factor (IGF) binding protein-3 and siRNA targeting IGF-1 receptor. Results: Cisplatin-R cells illustrated greater expression of the markers CD133more » and aldehyde dehydrogenase, more rapid in vivo tumor growth, more resistance to cisplatin- and etoposide-induced apoptosis, and greater survival after treatment with cisplatin or radiation than the parental H460 cells. Also, cisplatin-R demonstrated decreased expression of insulin-like growth factor binding protein-3 and increased activation of IGF-1 receptor signaling compared with parental H460 cells in the presence of IGF-1. Human recombinant IGF binding protein-3 reversed cisplatin resistance in cisplatin-R cells and targeting of IGF-1 receptor using siRNA resulted in sensitization of cisplatin-R-cells to cisplatin and radiation. Conclusions: The IGF-1 signaling pathway contributes to cisplatin-R to cisplatin and radiation. Thus, this pathway represents a potential target for improved lung cancer response to treatment.« less

Perceived orientation in physical and virtual environments: changes in perceived orientation as a function of idiothetic information available

NASA Technical Reports Server (NTRS)

Lathrop, William B.; Kaiser, Mary K.

2002-01-01

Two experiments examined perceived spatial orientation in a small environment as a function of experiencing that environment under three conditions: real-world, desktop-display (DD), and head-mounted display (HMD). Across the three conditions, participants acquired two targets located on a perimeter surrounding them, and attempted to remember the relative locations of the targets. Subsequently, participants were tested on how accurately and consistently they could point in the remembered direction of a previously seen target. Results showed that participants were significantly more consistent in the real-world and HMD conditions than in the DD condition. Further, it is shown that the advantages observed in the HMD and real-world conditions were not simply due to nonspatial response strategies. These results suggest that the additional idiothetic information afforded in the real-world and HMD conditions is useful for orientation purposes in our presented task domain. Our results are relevant to interface design issues concerning tasks that require spatial search, navigation, and visualization.

Preparation and Immunoaffinity Depletion of Fresh Frozen Tissue Homogenates for Mass Spectrometry-Based Proteomics in the Context of Drug Target/Biomarker Discovery.

PubMed

Prieto, DaRue A; Chan, King C; Johann, Donald J; Ye, Xiaoying; Whitely, Gordon; Blonder, Josip

2017-01-01

The discovery of novel drug targets and biomarkers via mass spectrometry (MS)-based proteomic analysis of clinical specimens has proven to be challenging. The wide dynamic range of protein concentration in clinical specimens and the high background/noise originating from highly abundant proteins in tissue homogenates and serum/plasma encompass two major analytical obstacles. Immunoaffinity depletion of highly abundant blood-derived proteins from serum/plasma is a well-established approach adopted by numerous researchers; however, the utilization of this technique for immunodepletion of tissue homogenates obtained from fresh frozen clinical specimens is lacking. We first developed immunoaffinity depletion of highly abundant blood-derived proteins from tissue homogenates, using renal cell carcinoma as a model disease, and followed this study by applying it to different tissue types. Tissue homogenate immunoaffinity depletion of highly abundant proteins may be equally important as is the recognized need for depletion of serum/plasma, enabling more sensitive MS-based discovery of novel drug targets, and/or clinical biomarkers from complex clinical samples. Provided is a detailed protocol designed to guide the researcher through the preparation and immunoaffinity depletion of fresh frozen tissue homogenates for two-dimensional liquid chromatography, tandem mass spectrometry (2D-LC-MS/MS)-based molecular profiling of tissue specimens in the context of drug target and/or biomarker discovery.

Impact of Competency-Based and Target-Oriented Training on Employee Performance: A Case Study

ERIC Educational Resources Information Center

Arslan, Ridvan; Uzaslan, N. Tufan

2017-01-01

Some firms have applied different in-house training models to keep up with new technological innovations in their specific fields. This study investigated how a target-oriented in-house training programme should be developed and how it should be evaluated for effectiveness. The aim of the study was to develop, implement and evaluate a…

Motives for physical exercise participation as a basis for the development of patient-oriented exercise interventions in osteoarthritis: a cross-sectional study.

PubMed

Krauss, Inga; Katzmarek, Uwe; Rieger, Monika A; Sudeck, Gorden

2017-08-01

Physical exercises are effective in the treatment of osteoarthritis (OA). There is consensus that exercise interventions should take into account the patient's preferences and needs in order to improve compliance to exercise regimes. One important personal factor is the patient's motivation for physical exercise. Health improvement is a relevant motive for exercise participation. Accordingly, exercise interventions primarily focus on health related needs such as strengthening and pain reduction. However exercising provides further many-faceted incentives that may foster exercise adherence. The present study aimed to characterize target groups for person-tailored exercise interventions in OA according to the International Classification of Functioning and Disability and Health (ICF). Target groups should be classified by similar individual exercise participation motive profiles and further described by their disease-related symptoms, limitations and psychological determinants of exercise behavior. Observational study via self-administered questionnaires. Community. We enrolled 292 adults with hip/knee OA living independently of assistance. Participants completed the Bernese Motive and Goal Inventory in Leisure and Health Sports (BMZI), the Hannover Functional Ability Questionnaire for Osteoarthritis, the WOMAC-Index (pain/stiffness), the General Self-efficacy Scale and a questionnaire on perceived barriers to exercise participation. The BMZI-scales served as active variables for cluster analysis (Ward's method), other scales were used as passive variables to further describe the identified clusters. Four clusters were defined using five exercise participation motives: health, body/appearance, esthetics, nature, and contact. Based on the identified motive profiles the target groups are labelled health-focused sports people; sporty, nature-oriented individualists; functionalists primarily motivated by maintaining or improving health through exercise; and nature-oriented, health-conscious exercisers. This study contributes to the development of person-oriented exercise recommendations with a special regard to motives for exercise participation. This study delineates four phenotypes with distinctive profiles of facilitators and barriers to exercise behavior. Key aspects of person-oriented exercise interventions could be defined according to each phenotype. Incentives related to physical exercise such as enjoyment, contact, or natural environment may encourage compliance to an exercise intervention. Goal setting in the context of OA rehabilitation should therefore not only refer to health-oriented reasons but also reconsider individual motives for exercise participation.

Automatic attentional orienting to other people's gaze in schizophrenia.

PubMed

Langdon, Robyn; Seymour, Kiley; Williams, Tracey; Ward, Philip B

2017-08-01

Explicit tests of social cognition have revealed pervasive deficits in schizophrenia. Less is known of automatic social cognition in schizophrenia. We used a spatial orienting task to investigate automatic shifts of attention cued by another person's eye gaze in 29 patients and 28 controls. Central photographic images of a face with eyes shifted left or right, or looking straight ahead, preceded targets that appeared left or right of the cue. To examine automatic effects, cue direction was non-predictive of target location. Cue-target intervals were 100, 300, and 800 ms. In non-social control trials, arrows replaced eye-gaze cues. Both groups showed automatic attentional orienting indexed by faster reaction times (RTs) when arrows were congruent with target location across all cue-target intervals. Similar congruency effects were seen for eye-shift cues at 300 and 800 ms intervals, but patients showed significantly larger congruency effects at 800 ms, which were driven by delayed responses to incongruent target locations. At short 100-ms cue-target intervals, neither group showed faster RTs for congruent than for incongruent eye-shift cues, but patients were significantly slower to detect targets after direct-gaze cues. These findings conflict with previous studies using schematic line drawings of eye-shifts that have found automatic attentional orienting to be reduced in schizophrenia. Instead, our data indicate that patients display abnormalities in responding to gaze direction at various stages of gaze processing-reflected by a stronger preferential capture of attention by another person's direct eye contact at initial stages of gaze processing and difficulties disengaging from a gazed-at location once shared attention is established.

A Cross-Cultural Longitudinal Examination of the Effect of Cumulative Adversity on the Mental and Physical Health of Older Adults

PubMed Central

Palgi, Yuval; Shrira, Amit

2015-01-01

Self-oriented adversity refers to traumatic events that primarily inflict the self, whereas other-oriented adversity refers to events that affect the self by primarily targeting others. The present study aimed to examine whether cultural background moderates the effects of self-oriented and other-oriented adversity on mental and physical health of older adults. Using longitudinal data from the Israeli component of the Survey of Health and Retirement, we focused on 370 Jews and 239 Arabs who reported their exposure to various adversities across the lifespan, and completed questionnaires regarding mental and physical health. Results showed that the effect of self-oriented adversity on health did not differ among Jews and Arabs. However, other-oriented adversity showed a stronger effect on Arabs’ mental and physical health than on Jews’ health. Our findings suggest that the accumulation of adverse events that affect the self by primarily targeting others may have a stronger impact in collectivist cultures than in individualist cultures. PMID:25961862

[Obstacles for the use of early childhood prevention services : The role of expected ability to control sources].

PubMed

Neumann, Anna; Renner, Ilona

2016-10-01

It is well established that preventive measures for pregnant women and families with small children do not reach all families alike. Often enough, it is those families, who due to heightened stresses and strains might gain the most from these measures, who cannot be reached (dilemma of prevention). This investigation explores whether parents can be grouped according to their views on health, prevention and measures available to young families, and whether belonging to one of the identified groups explains differences in the use of (primary and secondary) preventive measures for pregnant women and young families. In the context of home visits, parents of children aged two to four years (N = 273) completed questionnaires. Additionally, 203 parents took part in qualitative interviews. Based on interview data, parents from different sociocultural backgrounds could be grouped along their expected ability to control sources for parental support (Steuerungskompetenz). Parents high and low in Steuerungskompetenz differ regarding their knowledge of, use of, and satisfaction with (primary) preventive measures. Steuerungskompetenz explains the use of primary preventive measures above and beyond socioeconomic control variables as well as family stresses and strains. The use of secondary preventive measures is better explained by family stresses and strains. Results are discussed in terms of untapped services, needs and possibilities of target group-oriented approach.

Matched Behavioral and Neural Adaptations for Low Sound Level Echolocation in a Gleaning Bat, Antrozous pallidus.

PubMed

Measor, Kevin R; Leavell, Brian C; Brewton, Dustin H; Rumschlag, Jeffrey; Barber, Jesse R; Razak, Khaleel A

2017-01-01

In active sensing, animals make motor adjustments to match sensory inputs to specialized neural circuitry. Here, we describe an active sensing system for sound level processing. The pallid bat uses downward frequency-modulated (FM) sweeps as echolocation calls for general orientation and obstacle avoidance. The bat's auditory cortex contains a region selective for these FM sweeps (FM sweep-selective region, FMSR). We show that the vast majority of FMSR neurons are sensitive and strongly selective for relatively low levels (30-60 dB SPL). Behavioral testing shows that when a flying bat approaches a target, it reduces output call levels to keep echo levels between ∼30 and 55 dB SPL. Thus, the pallid bat behaviorally matches echo levels to an optimized neural representation of sound levels. FMSR neurons are more selective for sound levels of FM sweeps than tones, suggesting that across-frequency integration enhances level tuning. Level-dependent timing of high-frequency sideband inhibition in the receptive field shapes increased level selectivity for FM sweeps. Together with previous studies, these data indicate that the same receptive field properties shape multiple filters (sweep direction, rate, and level) for FM sweeps, a sound common in multiple vocalizations, including human speech. The matched behavioral and neural adaptations for low-intensity echolocation in the pallid bat will facilitate foraging with reduced probability of acoustic detection by prey.

Matched Behavioral and Neural Adaptations for Low Sound Level Echolocation in a Gleaning Bat, Antrozous pallidus

PubMed Central

Measor, Kevin R.; Leavell, Brian C.; Brewton, Dustin H.; Rumschlag, Jeffrey; Barber, Jesse R.

2017-01-01

Abstract In active sensing, animals make motor adjustments to match sensory inputs to specialized neural circuitry. Here, we describe an active sensing system for sound level processing. The pallid bat uses downward frequency-modulated (FM) sweeps as echolocation calls for general orientation and obstacle avoidance. The bat’s auditory cortex contains a region selective for these FM sweeps (FM sweep-selective region, FMSR). We show that the vast majority of FMSR neurons are sensitive and strongly selective for relatively low levels (30-60 dB SPL). Behavioral testing shows that when a flying bat approaches a target, it reduces output call levels to keep echo levels between ∼30 and 55 dB SPL. Thus, the pallid bat behaviorally matches echo levels to an optimized neural representation of sound levels. FMSR neurons are more selective for sound levels of FM sweeps than tones, suggesting that across-frequency integration enhances level tuning. Level-dependent timing of high-frequency sideband inhibition in the receptive field shapes increased level selectivity for FM sweeps. Together with previous studies, these data indicate that the same receptive field properties shape multiple filters (sweep direction, rate, and level) for FM sweeps, a sound common in multiple vocalizations, including human speech. The matched behavioral and neural adaptations for low-intensity echolocation in the pallid bat will facilitate foraging with reduced probability of acoustic detection by prey. PMID:28275715

A tool to assess knowledge, attitude and behavior of Indonesian health care workers regarding infection control.

PubMed

Duerink, D O; Hadi, U; Lestari, E S; Roeshadi, Djoko; Wahyono, Hendro; Nagelkerke, N J D; Van der Meulen, R G; Van den Broek, P J

2013-07-01

to investigate knowledge, attitude and behaviour toward infection control in two teaching hospitals on the island of Java by means of a questionnaire and to evaluate the use of the questionnaire as a tool. we investigated knowledge, attitude and behaviour toward infection control in two teaching hospitals on the island of Java by means of a questionnaire to identify problem areas, barriers and facilitators. The target was to include at least 50% of all health care workers (physicians, nurses, assistant nurses and infection control nurses) in each hospital, department and profession. Differences between demographic variables and scores for individual questions and groups of questions were compared using the chi-square statistic and analysis of variance and Spearman's rho was used to test for correlations between knowledge, attitude, self-reported behaviour and perceived obstacles. more than half of the health care workers of the participating departments completed the questionnaire. Of the 1036 respondents (44% nurses, 37% physicians and 19% assistant nurses), 34% were vaccinated against hepatitis B, 77% had experienced needle stick accidents and 93% had been instructed about infection control. The mean of the correct answers to the knowledge questions was 44%; of the answers to the attitude questions 67% were in agreement with the correct attitude; obstacles to compliance with infection control guidelines were perceived in 30% of the questions and the mean self-reported compliance was 63%. Safe handling of sharps, hand hygiene and the use of personal protective equipment were identified as the most important aspects for interventions. Significant positive correlations were found between knowledge, attitude, self-reported behaviour and perceived obstacles. the questionnaire in conjunction with site visits and interviews was a valuable strategy to identify trouble spots in the hospitals and to determine barriers to facilitators of change that should be taken into account when planning interventions. Successful interventions should cover hospital management, the infection control team, as well as the health care workers on the wards.

Application of particle swarm optimization in path planning of mobile robot

NASA Astrophysics Data System (ADS)

Wang, Yong; Cai, Feng; Wang, Ying

2017-08-01

In order to realize the optimal path planning of mobile robot in unknown environment, a particle swarm optimization algorithm based on path length as fitness function is proposed. The location of the global optimal particle is determined by the minimum fitness value, and the robot moves along the points of the optimal particles to the target position. The process of moving to the target point is done with MATLAB R2014a. Compared with the standard particle swarm optimization algorithm, the simulation results show that this method can effectively avoid all obstacles and get the optimal path.

Cell-based immunotherapy in gynecologic malignancies.

PubMed

Schaar, Bruce; Krishnan, Venkatesh; Tallapragada, Supreeti; Dorigo, Oliver

2018-02-01

To provide an overview of the principles, safety and efficacy of adoptive cell therapy (ACT) in solid tumors particularly in gynecological cancers. Efforts to target solid tumors using tumor-infiltrating lymphocytes and genetically modified T cells have shown promising efficacy in some patients. Two food and drug administration approvals for the treatment of leukemia are the first gene therapies available for cancer treatment in the United States. Genetic engineering of antitumor immunity using T cells has the potential to target specific tumor-associated antigens and overcome obstacles to successful immunotherapy like immune-suppressive factors in the tumor microenvironment.

View-Based Organization and Interplay of Spatial Working and Long-Term Memories

PubMed Central

Röhrich, Wolfgang G.; Hardiess, Gregor; Mallot, Hanspeter A.

2014-01-01

Space perception provides egocentric, oriented views of the environment from which working and long-term memories are constructed. “Allocentric” (i.e. position-independent) long-term memories may be organized as graphs of recognized places or views but the interaction of such cognitive graphs with egocentric working memories is unclear. Here we present a simple coherent model of view-based working and long-term memories, together with supporting evidence from behavioral experiments. The model predicts that within a given place, memories for some views may be more salient than others, that imagery of a target square should depend on the location where the recall takes place, and that recall favors views of the target square that would be obtained when approaching it from the current recall location. In two separate experiments in an outdoor urban environment, pedestrians were approached at various interview locations and asked to draw sketch maps of one of two well-known squares. Orientations of the sketch map productions depended significantly on distance and direction of the interview location from the target square, i.e. different views were recalled at different locations. Further analysis showed that location-dependent recall is related to the respective approach direction when imagining a walk from the interview location to the target square. The results are consistent with a view-based model of spatial long-term and working memories and their interplay. PMID:25409437

Color is processed less efficiently than orientation in change detection but more efficiently in visual search.

PubMed

Huang, Liqiang

2015-05-01

Basic visual features (e.g., color, orientation) are assumed to be processed in the same general way across different visual tasks. Here, a significant deviation from this assumption was predicted on the basis of the analysis of stimulus spatial structure, as characterized by the Boolean-map notion. If a task requires memorizing the orientations of a set of bars, then the map consisting of those bars can be readily used to hold the overall structure in memory and will thus be especially useful. If the task requires visual search for a target, then the map, which contains only an overall structure, will be of little use. Supporting these predictions, the present study demonstrated that in comparison to stimulus colors, bar orientations were processed more efficiently in change-detection tasks but less efficiently in visual search tasks (Cohen's d = 4.24). In addition to offering support for the role of the Boolean map in conscious access, the present work also throws doubts on the generality of processing visual features. © The Author(s) 2015.

Visual search for features and conjunctions in development.

PubMed

Lobaugh, N J; Cole, S; Rovet, J F

1998-12-01

Visual search performance was examined in three groups of children 7 to 12 years of age and in young adults. Colour and orientation feature searches and a conjunction search were conducted. Reaction time (RT) showed expected improvements in processing speed with age. Comparisons of RT's on target-present and target-absent trials were consistent with parallel search on the two feature conditions and with serial search in the conjunction condition. The RT results indicated searches for feature and conjunctions were treated similarly for children and adults. However, the youngest children missed more targets at the largest array sizes, most strikingly in conjunction search. Based on an analysis of speed/accuracy trade-offs, we suggest that low target-distractor discriminability leads to an undersampling of array elements, and is responsible for the high number of misses in the youngest children.

Targeted Research and Technology Within NASA's Living With a Star Program

NASA Technical Reports Server (NTRS)

Antiochos, Spiro; Baker, Kile; Bellaire, Paul; Blake, Bern; Crowley, Geoff; Eddy, Jack; Goodrich, Charles; Gopalswamy, Nat; Gosling, Jack; Hesse, Michael

2004-01-01

Targeted Research & Technology (TR&T) NASA's Living With a Star (LWS) initiative is a systematic, goal-oriented research program targeting those aspects of the Sun-Earth system that affect society. The Targeted Research and Technology (TR&T) component of LWS provides the theory, modeling, and data analysis necessary to enable an integrated, system-wide picture of Sun-Earth connection science with societal relevance. Recognizing the central and essential role that TR&T would have for the success of the LWS initiative, the LWS Science Architecture Team (SAT) recommended that a Science Definition Team (SDT), with the same status as a flight mission definition team, be formed to design and coordinate a TR&T program having prioritized goals and objectives that focused on practical societal benefits. This report details the SDT recommendations for the TR&T program.

Formation of Amorphous Carbon Nanoparticles by the Laser Electrodispersion Method

NASA Astrophysics Data System (ADS)

Gurevich, S. A.; Gorokhov, M. V.; Kozhevin, V. M.; Kukushkin, M. V.; Levitskii, V. S.; Markov, L. K.; Yavsin, D. A.

2018-03-01

Experimental results on the laser ablation of the highly oriented pyrolytic graphite by using light pulses of an Nd:YAG laser (pulse width 25 ns, pulse energy 220 mJ) are presented. Analysis of the surface profile of the carbon target shows that the target material melts in the course of the laser ablation. As a result of ablation, a coating consisting of carbon nanoparticles about 10 nm in size is formed on the substrate placed at a distance of 4 cm from the target. It is assumed that such particles are formed as a result of the electrodispersion of carbon droplets detached from the target surface and charged to an unstable state in the laser plasma plume. Raman spectra of the coatings indicate that the carbon nanoparticles being formed have an amorphous structure.

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

Position and orientation tracking system

DOEpatents

Burks, Barry L.; DePiero, Fred W.; Armstrong, Gary A.; Jansen, John F.; Muller, Richard C.; Gee, Timothy F.

1998-01-01

A position and orientation tracking system presents a laser scanning appaus having two measurement pods, a control station, and a detector array. The measurement pods can be mounted in the dome of a radioactive waste storage silo. Each measurement pod includes dual orthogonal laser scanner subsystems. The first laser scanner subsystem is oriented to emit a first line laser in the pan direction. The second laser scanner is oriented to emit a second line laser in the tilt direction. Both emitted line lasers scan planes across the radioactive waste surface to encounter the detector array mounted on a target robotic vehicle. The angles of incidence of the planes with the detector array are recorded by the control station. Combining measurements describing each of the four planes provides data for a closed form solution of the algebraic transform describing the position and orientation of the target robotic vehicle.

Position and orientation tracking system

DOEpatents

Burks, B.L.; DePiero, F.W.; Armstrong, G.A.; Jansen, J.F.; Muller, R.C.; Gee, T.F.

1998-05-05

A position and orientation tracking system presents a laser scanning apparatus having two measurement pods, a control station, and a detector array. The measurement pods can be mounted in the dome of a radioactive waste storage silo. Each measurement pod includes dual orthogonal laser scanner subsystems. The first laser scanner subsystem is oriented to emit a first line laser in the pan direction. The second laser scanner is oriented to emit a second line laser in the tilt direction. Both emitted line lasers scan planes across the radioactive waste surface to encounter the detector array mounted on a target robotic vehicle. The angles of incidence of the planes with the detector array are recorded by the control station. Combining measurements describing each of the four planes provides data for a closed form solution of the algebraic transform describing the position and orientation of the target robotic vehicle. 14 figs.

Localized landslide risk assessment with multi pass L band DInSAR analysis

NASA Astrophysics Data System (ADS)

Yun, HyeWon; Rack Kim, Jung; Lin, Shih-Yuan; Choi, YunSoo

2014-05-01

In terms of data availability and error correction, landslide forecasting by Differential Interferometric SAR (DInSAR) analysis is not easy task. Especially, the landslides by the anthropogenic construction activities frequently occurred in the localized cutting side of mountainous area. In such circumstances, it is difficult to attain sufficient enough accuracy because of the external factors inducing the error component in electromagnetic wave propagation. For instance, the local climate characteristics such as orographic effect and the proximity to water source can produce the significant anomalies in the water vapor distribution and consequently result in the error components of InSAR phase angle measurements. Moreover the high altitude parts of target area cause the stratified tropospheric delay error in DInSAR measurement. The other obstacle in DInSAR observation over the potential landside site is the vegetation canopy which causes the decorrelation of InSAR phase. Thus rather than C band sensor such as ENVISAT, ERS and RADARSAT, DInSAR analysis with L band ALOS PLASAR is more recommendable. Together with the introduction of L band DInSAR analysis, the improved DInSAR technique to cope all above obstacles is necessary. Thus we employed two approaches i.e. StaMPS/MTI (Stanford Method for Persistent Scatterers/Multi-Temporal InSAR, Hopper et al., 2007) which was newly developed for extracting the reliable deformation values through time series analysis and two pass DInSAR with the error term compensation based on the external weather information in this study. Since the water vapor observation from spaceborne radiometer is not feasible by the temporal gap in this case, the quantities from weather Research Forecasting (WRF) with 1 km spatial resolution was used to address the atmospheric phase error in two pass DInSAR analysis. Also it was observed that base DEM offset with time dependent perpendicular baselines of InSAR time series produce a significant error even in the advanced time series techniques such as StaMPS/MTI. We tried to compensate with the algorithmic base together with the usage of high resolution LIDAR DEM. The target area of this study is the eastern part of Korean peninsula centered. In there, the landslide originated by the geomorphic factors such as high sloped topography and localized torrential down pour is critical issue. The surface deformations from error corrected two pass DInSAR and StaMPS/MTI are crossly compared and validated with the landslide triggering factors such as vegetation, slope and geological properties. The study will be further extended for the application of future SAR sensors by incorporating the dynamic analysis of topography to implement practical landslide forecasting scheme.

Enceladus Jet Orientations: Effects of Surface Structure

NASA Astrophysics Data System (ADS)

Helfenstein, P.; Porco, C.; DiNino, D.

2013-12-01

Jetting activity across the South Polar Terrain (SPT) of Enceladus is now known to erupt directly from tiger-stripe rifts and associated fracture systems. However, details of the vent conduit geometry are hidden below the icy surface. The three-dimensional orientations of the erupting jets may provide important clues. Porco et al. (2013, Lunar Planet. Sci. Conf. 44th, p.1775) surveyed jet locations and orientations as imaged at high resolution (< 1.3 km/pixel) by Cassini ISS from 2005 through May 2012. Ninety-eight (98) jets were identified either on the main trunks or branches of the 4 tiger-stripes. The azimuth angles of the jets are seen to vary across the SPT. Here, we use histogram analysis of the survey data to test if the jet azimuths are influenced by their placement relative to surface morphology and tectonic structures. Azimuths are measured positive counterclockwise with zero pointing along the fracture in the direction of the sub-Saturn hemisphere, and rosette histograms were binned in 30° increments. Overall, the jet azimuths are not random and only about 11% of them are co-aligned with the tiger stripe valley. There are preferred diagonal orientations between 105°-165° and again between 255°-345°. These trends are dominant along the Damascus and Baghdad tiger-stripes where more than half of the jets are found. Histograms for Cairo and Alexandria show less-distinct trends, fewer jets being measured there, but combining data from both suggests a different pattern of preferred orientations; from 45°-75° and 265°-280°. Many possible factors could affect the orientations of jets, for example, the conduit shape, the presence of obstacles like narrow medial ridges called 'shark-fins' along tiger-stripe valleys, the possibility that jets may breach the surface at some point other than the center of a tiger-stripe, and the presence of structural fabrics or mechanical weaknesses, such as patterns of cross-cutting fractures. The dominance of diagonally crossing azimuths for Damascus and Baghdad suggest that cross-cutting fractures may significantly control jet orientations. At the 100 m/pixel scale of our Enceladus basemap at least 24% of the jets have azimuth orientations that point along or parallel to nearby fractures or fabrics of parallel fractures that approach or intersect the tiger stripe. Structural control of jet orientations by local tectonism is especially suggested by a systematic pattern of jet orientations at the distal end of Damascus Sulcus where it bifurcates into a northern and a southern branch, respectively. The five most distal jets along the northern branch are nearly parallel and point northward while the three most distal jets along the southern branch are also nearly parallel, but they point in the opposite direction. Additional work is needed to show the extent to which jet orientations may be affected at smaller scales by quasi-parallel systems of cross-cutting gossamer fractures or by curving axial discontinuities along the tiger stripes (cf. Helfenstein et al. 2011, http://encfg.ciclops.org/reg/uploads/20110425220109_helfenstein_enceladus_workshop_2011.pdf).

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.

Sustainable tourism and harmonious culture: a case study of cultic model at village tourism

NASA Astrophysics Data System (ADS)

Astawa, I. P.; Triyuni, N. N.; Santosa, I. D. M. C.

2018-01-01

The research aims to analyze an event model of Culture and Tourism International Camp (Cultic) from two aspects, harmonious culture and sustainable tourism. Currently, Indonesian government promotes village tourism by involving more villagers to achieve village independence in its development. The program has faced various obstacles, such as the eroded local cultures due to the development of a massive and money-oriented tourism with less attention on the environmental damage. One of the offered programs is a green tourism model for an event named Culture and Tourism International Camps - Cultic. The research is conducted in several stages. The first stage is the development of model based on the theoretical study. The second stage is the implementation of the model with 85 participants. The third stage is the evaluation of the model through harmonious culture and sustainable tourism approaches. The data is collected through a direct observation and a questionnaire. The result of qualitative analysis indicates that the developed event model supports the harmonious culture, especially the natural environment. Whereas, the result of quantitative analysis indicates that the participants enjoy the activities, such as green food, material natural, waste management, and ecosystem. Another finding is that the community strongly supports the concept of sustainable tourism.

Promoting women entrepreneurs in Lebanon: the experience of UNIFEM.

PubMed

Husseini, R

1997-02-01

The work of the United Nations Development Fund for Women (UNIFEM) in West Asia began in 1994 with a regional program to strengthen women-owned enterprises in Jordan, Syria, and Lebanon. In Lebanon, a survey of 100 women entrepreneurs, as well as nontraditional credit programs and banks, was conducted prior to program design. A second survey assessed micro-entrepreneurs' demands for financial and other services. Since gender analysis was a new concept in Lebanon, UNIFEM organized a gender awareness workshop for representatives of government, nongovernmental organizations, and the banking sector, followed by a strategic planning workshop. The surveys confirmed that women were concentrated mainly in the less profitable economic sectors, producing handicrafts and food products or running small service or trading companies. Women were less likely than men to get bank loans or to register their businesses. Women's problems accessing credit--the main obstacle limiting their ability to develop their businesses--were compounded by their lack of information, male-oriented collateral requirements, and discriminatory banking regulations. UNIFEM decided to channel counseling of women entrepreneurs on legal matters, marketing, and credit sources through the Ministry of Social Affairs. It is expected that knowledge of gender-related employment issues and the use of gender-specific analysis will become integral to the Ministry's program as a result.

[The poster as a communication medium].

PubMed

Tovar Samanez, C

1987-01-01

The poster as a medium of communication serves to transmit a message by means of a graphical synthesis. It elicits attention by its originality, contrast, and focus on the center of interest. The poster is effective if the images and slogans can be identified easily. Its visual attractiveness is also essential. The understanding of the message is the function of the cultural characteristics of the public with symbols, metaphors, gestures, and detailed description. The appeal of the message allows the public to accept it on sensorial, emotional, social, intellectual, and economical levels. Adverse motivations should not be confused with the positive appeal (prejudice, preconceived ideas, and bias). Confusion and ambiguity can carry conflicting messages, therefore negative examples should be avoided. The force of the message targets the memory carrying conviction and calling to action. The target group and objective must be defined as to age, occupation, location, and sex. The message also has to be defined precisely for the target audience. It is in the analysis of the context whereby the poster is received as to notions of the target topic, alternative attitudes relative to the promotion of the message, obstacles that are encountered in the mentality of the target, and cultural characteristics of the target audience. The text of the slogan must be given before drawing the poster. The designing of the poster should be creative with association of ideas, metaphors and symbols, descriptive images, fusion of symbolic and descriptive forms, humor, the fusion of graphics with letters, and the fusion of letters with images. Completed forms of the poster use illustration, photography, typography, calligraphy, and photo montage.

Impact of water drops on small targets

NASA Astrophysics Data System (ADS)

Rozhkov, A.; Prunet-Foch, B.; Vignes-Adler, M.

2002-10-01

The collision of water drops against small targets was studied experimentally by means of a high-speed photography technique. The drop impact velocity was about 3.5 m/s. Drop diameters were in the range of 2.8-4.0 mm. The target was a stainless steel disk of 3.9 mm diameter. The drop spread beyond the target like a central cap surrounded by a thin, slightly conical lamella bounded by a thicker rim. By mounting a small obstacle near the target, surface-tension driven Mach waves in the flowing lamella were generated, which are formally equivalent to the familiar compressibility driven Mach waves in gas dynamics. From the measurement of the Mach angle, the values of some flow parameters could be obtained as functions of time, which provided insight into the flow structure. The liquid flowed from the central cap to the liquid rim through the thin lamella at constant momentum flux. At a certain stage of the process, most of the liquid accumulated in the rim and the internal part of the lamella became metastable. In this situation, a rupture wave propagating through the metastable internal part of the lamella caused the rim to retract while forming outwardly directed secondary jets. The jets disintegrated into secondary droplets due to the Savart-Plateau-Rayleigh instability. Prior to the end of the retraction, an internal circular wave of rupture was formed. It originated at the target and then it propagated to meet the retracting rim. Their meeting resulted in a crown of tiny droplets. A theoretical analysis of the ejection process is proposed.

Improved prediction of antibody VL–VH orientation

PubMed Central

Marze, Nicholas A.; Lyskov, Sergey; Gray, Jeffrey J.

2016-01-01

Antibodies are important immune molecules with high commercial value and therapeutic interest because of their ability to bind diverse antigens. Computational prediction of antibody structure can quickly reveal valuable information about the nature of these antigen-binding interactions, but only if the models are of sufficient quality. To achieve high model quality during complementarity-determining region (CDR) structural prediction, one must account for the VL–VH orientation. We developed a novel four-metric VL–VH orientation coordinate frame. Additionally, we extended the CDR grafting protocol in RosettaAntibody with a new method that diversifies VL–VH orientation by using 10 VL–VH orientation templates rather than a single one. We tested the multiple-template grafting protocol on two datasets of known antibody crystal structures. During the template-grafting phase, the new protocol improved the fraction of accurate VL–VH orientation predictions from only 26% (12/46) to 72% (33/46) of targets. After the full RosettaAntibody protocol, including CDR H3 remodeling and VL–VH re-orientation, the new protocol produced more candidate structures with accurate VL–VH orientation than the standard protocol in 43/46 targets (93%). The improved ability to predict VL–VH orientation will bolster predictions of other parts of the paratope, including the conformation of CDR H3, a grand challenge of antibody homology modeling. PMID:27276984

Independent effects of reward expectation and spatial orientation on the processing of emotional facial expressions.

PubMed

Kang, Guanlan; Zhou, Xiaolin; Wei, Ping

2015-09-01

The present study investigated the effect of reward expectation and spatial orientation on the processing of emotional facial expressions, using a spatial cue-target paradigm. A colored cue was presented at the left or right side of the central fixation point, with its color indicating the monetary reward stakes of a given trial (incentive vs. non-incentive), followed by the presentation of an emotional facial target (angry vs. neutral) at a cued or un-cued location. Participants were asked to discriminate the emotional expression of the target, with the cue-target stimulus onset asynchrony being 200-300 ms in Experiment 1 and 950-1250 ms in Experiment 2a (without a fixation cue) and Experiment 2b (with a fixation cue), producing a spatial facilitation effect and an inhibition of return effect, respectively. The results of all the experiments revealed faster reaction times in the monetary incentive condition than in the non-incentive condition, demonstrating the effect of reward to facilitate task performance. An interaction between reward expectation and the emotion of the target was evident in all the three experiments, with larger reward effects for angry faces than for neutral faces. This interaction was not affected by spatial orientation. These findings demonstrate that incentive motivation improves task performance and increases sensitivity to angry faces, irrespective of spatial orienting and reorienting processes.

Distraction by emotional sounds: Disentangling arousal benefits and orienting costs.

PubMed

Max, Caroline; Widmann, Andreas; Kotz, Sonja A; Schröger, Erich; Wetzel, Nicole

2015-08-01

Unexpectedly occurring task-irrelevant stimuli have been shown to impair performance. They capture attention away from the main task leaving fewer resources for target processing. However, the actual distraction effect depends on various variables; for example, only target-informative distractors have been shown to cause costs of attentional orienting. Furthermore, recent studies have shown that high arousing emotional distractors, as compared with low arousing neutral distractors, can improve performance by increasing alertness. We aimed to separate costs of attentional orienting and benefits of arousal by presenting negative and neutral environmental sounds (novels) as oddballs in an auditory-visual distraction paradigm. Participants categorized pictures while task-irrelevant sounds preceded visual targets in two conditions: (a) informative sounds reliably signaled onset and occurrence of visual targets, and (b) noninformative sounds occurred unrelated to visual targets. Results confirmed that only informative novels yield distraction. Importantly, irrespective of sounds' informational value participants responded faster in trials with high arousing negative as compared with moderately arousing neutral novels. That is, costs related to attentional orienting are modulated by information, whereas benefits related to emotional arousal are independent of a sound's informational value. This favors a nonspecific facilitating cross-modal influence of emotional arousal on visual task performance and suggests that behavioral distraction by noninformative novels is controlled after their motivational significance has been determined. (c) 2015 APA, all rights reserved).