Science.gov

Sample records for a-k gap distance

  1. Unifying Paschen Curve Conditions across Pressure and Gap Distance

    NASA Astrophysics Data System (ADS)

    Loveless, Amanda; Garner, Allen; Valfells, Agust

    2015-11-01

    The Paschen curve (PC) predicts the breakdown voltage of a gas by relating it to the product of pressure and gap distance (pd). Recent experiments deviate from the PC for microscale gaps at low pd. A scaling law incorporating field emission-driven breakdown and field enhancement to the macroscale Paschen law yields more accurate predictions for microscale gaps (A. Venkattraman and A. A. Alexeenko, Phys. Plasmas 19, 123515 (2012).). While many studies consider low pd, deviations from the PC also arise at high pd, as demonstrated for gap distances between 0.0508 and 0.254 cm and pressures between 96.5 and 6900 kPa (W. J. Carey, A. J. Wiebe, R. D. Nord, and L. L. Altgilbers, in Proc. IEEE Pulsed Power Conf., 2011, pp. 741-744). High pd values are relevant for ongoing high voltage plasma experiments for food treatment and combustion. We attempt to elucidate the impact of large gap distances (~ 5 cm) and higher pressures (~ 200-300 kPa) on these deviations by connecting recent work at low pd to high pd by assessing scaling laws, analyzing field emission models, and using particle-in-cell codes. Implications on experimental design will be discussed, and the development of a universal Paschen curve will be explored.

  2. Avoiding the Goulash: Closing Gaps and Bridging Distances

    ERIC Educational Resources Information Center

    Shillington, Sandi; Brown, Mark; MacKay, Andrea; Paewai, Shelley; Suddaby, Gordon; White, Frances

    2012-01-01

    Not many universities provide both distance and on-campus study options for study. Massey University has been delivering both for more than 50 years. In this time there has been a significant change from paper-based to increasingly online delivery (both on-campus and at a distance). Services provided to students have also changed and adapted to…

  3. Avoiding the Goulash: Closing Gaps and Bridging Distances

    ERIC Educational Resources Information Center

    Shillington, Sandi; Brown, Mark; MacKay, Andrea; Paewai, Shelley; Suddaby, Gordon; White, Frances

    2012-01-01

    Not many universities provide both distance and on-campus study options for study. Massey University has been delivering both for more than 50 years. In this time there has been a significant change from paper-based to increasingly online delivery (both on-campus and at a distance). Services provided to students have also changed and adapted to…

  4. Variation of plasma parameters of vacuum arc column with gap distance

    NASA Astrophysics Data System (ADS)

    Han, Wen; Yuan, Zhao; He, Junjia

    2016-07-01

    On the basis of a two-dimensional (2D) magneto-hydrodynamic model, we studied long-gap-distance vacuum arcs in a uniform axial magnetic field and determined the effect of gap distance varying in a large range on plasma parameters. Simulation results showed that with increasing gap distance, the parameters of the plasma near the cathode are almost invariant, except for ion number density, but the parameters of the plasma in front of the anode clearly vary; meanwhile, joule heat gradually becomes the main source of energy for the arc column. In a short gap, a clear current constriction can be found in the entire arc column. Whereas when the gap distance exceeds a certain value, a sharp contraction of the current only arises in front of the anode.

  5. On the Spectral Gap of a Square Distance Matrix

    NASA Astrophysics Data System (ADS)

    Cheng, Xinyu; Li, Dong; Shirokoff, David; Wetton, Brian

    2017-02-01

    We consider a square distance matrix which arises from a preconditioned Jacobian matrix for the numerical computation of the Cahn-Hilliard problem. We prove strict negativity of all but one associated eigenvalues. This solves a conjecture in Christieb et al. (J Comput Phys 257:193-215, 2014).

  6. Distance-near disparity esotropia: can we shrink the gap?

    PubMed

    Burke, J P

    2015-02-01

    Distance-near disparity esotropias are a group of heterogenous usually acquired strabismus disorders, where the angle of misalignment at near exceeds that at distance by 10 prism diopters or more, where the accurate correction of refractive errors and ambylopia are important early objectives. These aetiologically diverse entities respond non-uniformally to strabismus surgery and bifocals. The management challenge is one of 'shrinking' the disparity so that the affected individuals can develop and comfortably maintain binocular single vision and/or optimal alignment. Surgical procedures have continued to evolve but none of the current operative procedures are superior for all patients. Subclassifying this strabismus and highlighting publication data from more homogenous clinical series may assist with the optimisation of future management and treatment outcomes.

  7. Depth scaling in phantom and monocular gap stereograms using absolute distance information.

    PubMed

    Kuroki, Daiichiro; Nakamizo, Sachio

    2006-11-01

    The present study aimed to investigate whether the visual system scales apparent depth from binocularly unmatched features by using absolute distance information. In Experiment 1 we examined the effect of convergence on perceived depth in phantom stereograms [Gillam, B., & Nakayama, K. (1999). Quantitative depth for a phantom surface can be based on cyclopean occlusion cues alone. Vision Research, 39, 109-112.], monocular gap stereograms [Pianta, M. J., & Gillam, B. J. (2003a). Monocular gap stereopsis: manipulation of the outer edge disparity and the shape of the gap. Vision Research, 43, 1937-1950.] and random dot stereograms. In Experiments 2 and 3 we examined the effective range of viewing distances for scaling the apparent depths in these stereograms. The results showed that: (a) the magnitudes of perceived depths increased in all stereograms as the estimate of the viewing distance increased while keeping proximal and/or distal sizes of the stimuli constant, and (b) the effective range of viewing distances was significantly shorter in monocular gap stereograms. The first result indicates that the visual system scales apparent depth from unmatched features as well as that from horizontal disparity, while the second suggests that, at far distances, the strength of the depth signal from an unmatched feature in monocular gap stereograms is relatively weaker than that from horizontal disparity.

  8. Influence of Gap Distance on Vacuum Arc Characteristics of Cup Type AMF Electrode in Vacuum Interrupters

    NASA Astrophysics Data System (ADS)

    Cheng, Shaoyong; Xiu, Shixin; Wang, Jimei; Shen, Zhengchao

    2006-11-01

    The greenhouse effect of SF6 is a great concern today. The development of high voltage vacuum circuit breakers becomes more important. The vacuum circuit breaker has minimum pollution to the environment. The vacuum interrupter is the key part of a vacuum circuit breaker. The interrupting characteristics in vacuum and arc-controlling technique are the main problems to be solved for a longer gap distance in developing high voltage vacuum interrupters. To understand the vacuum arc characteristics and provide effective technique to control vacuum arc in a long gap distance, the arc mode transition of a cup-type axial magnetic field electrode is observed by a high-speed charge coupled device (CCD) video camera under different gap distances while the arc voltage and arc current are recorded. The controlling ability of the axial magnetic field on vacuum arc obviously decreases when the gap distance is longer than 40 mm. The noise components and mean value of the arc voltage significantly increase. The effective method for controlling the vacuum arc characteristics is provided by long gap distances based on the test results. The test results can be used as a reference to develop high voltage and large capacity vacuum interrupters.

  9. Control of membrane gaps by synaptotagmin-Ca2+ measured with a novel membrane distance ruler

    NASA Astrophysics Data System (ADS)

    Lin, Chao-Chen; Seikowski, Jan; Pérez-Lara, Angel; Jahn, Reinhard; Höbartner, Claudia; Walla, Peter Jomo

    2014-12-01

    Fast synchronous neurotransmitter release is triggered by calcium that activates synaptotagmin-1 (syt-1), resulting in fusion of synaptic vesicles with the presynaptic membrane. Syt-1 possesses two Ca2+-binding C2 domains that tether membranes via interactions with anionic phospholipids. It is capable of crosslinking membranes and has recently been speculated to trigger fusion by decreasing the gap between them. As quantitative information on membrane gaps is key to understanding general cellular mechanisms, including the role of syt-1, we developed a fluorescence-lifetime based inter-membrane distance ruler using membrane-anchored DNAs of various lengths as calibration standards. Wild-type and mutant data provide evidence that full-length syt-1 indeed regulates membrane gaps: without Ca2+, syt-1 maintains membranes at distances of ~7-8 nm. Activation with 100 μM Ca2+ decreases the distance to ~5 nm by binding the C2 domains to opposing membranes, respectively. These values reveal that activated syt-1 adjusts membrane distances to the level that promotes SNARE complex assembly.

  10. Enrollment in Distance Education Classes Is Associated with Fewer Enrollment Gaps among Nontraditional Undergraduate Students in the US

    ERIC Educational Resources Information Center

    Pontes, Manuel C. F.; Pontes, Nancy M. H.

    2012-01-01

    The purpose of this research is to determine whether nontraditional undergraduate students in the US who enroll in distance education classes are less likely to have an enrollment gap (enrollment gap=part year enrollment). Previous research has shown that preference for distance education classes is significantly greater among nontraditional than…

  11. Effect of gap distance on tensile strength of preceramic base metal solder joints.

    PubMed

    Fattahi, Farnaz; Motamedi, Milad

    2011-01-01

    In order to fabricate prostheses with high accuracy and durability, soldering techniques have been introduced to clinical dentistry. However, these prostheses always fail at their solder joints. The purpose of this study was to evaluate the effect of gap distance on the tensile strength of base metal solder joints. Based on ADA/ISO 9693 specifications for tensile test, 40 specimens were fabricated from a Ni-Cr alloy and cut at the midpoint of 3-mm diameter bar and placed at desired positions by a specially designed device. The specimens were divided into four groups of 10 samples according to the desired solder gap distance: Group1: 0.1mm; Group2: 0.25mm; Group3: 0.5mm; and Group4: 0.75mm. After soldering, specimens were tested for tensile strength by a universal testing machine at a cross-head speed of 0.5mm/min with a preload of 10N. The mean tensile strength values of the groups were 162, 307.8, 206.1 and 336.7 MPa, respectively. The group with 0.75-mm gap had the highest and the group with 0.1-mm gap had the lowest tensile strength. Bonferroni test showed that Group1 and Group4 had statistically different values (P=0.023), but the differences between other groups were not sig-nificant at a significance level of 0.05. There was no direct relationship between increasing soldering gap distance and tensile strength of the solder joints.

  12. Effect of soldering techniques and gap distance on tensile strength of soldered Ni-Cr alloy joint

    PubMed Central

    Lee, Sang-Yeob

    2010-01-01

    PURPOSE The present study was intended to evaluate the effect of soldering techniques with infrared ray and gas torch under different gap distances (0.3 mm and 0.5 mm) on the tensile strength and surface porosity formation in Ni-Cr base metal alloy. MATERIALS AND METHODS Thirty five dumbbell shaped Ni-Cr alloy specimens were prepared and assigned to 5 groups according to the soldering method and the gap distance. For the soldering methods, gas torch (G group) and infrared ray (IR group) were compared and each group was subdivided by corresponding gap distance (0.3 mm: G3 and IR3, 0.5 mm: G5, IR5). Specimens of the experimental groups were sectioned in the middle with a diamond disk and embedded in solder blocks according to the predetermined distance. As a control group, 7 specimens were prepared without sectioning or soldering. After the soldering procedure, a tensile strength test was performed using universal testing machine at a crosshead speed 1 mm/min. The proportions of porosity on the fractured surface were calculated on the images acquired through the scanning electronic microscope. RESULTS Every specimen of G3, G5, IR3 and IR5 was fractured on the solder joint area. However, there was no significant difference between the test groups (P > .05). There was a negative correlation between porosity formation and tensile strength in all the specimens in the test groups (P < .05). CONCLUSION There was no significant difference in ultimate tensile strength of joints and porosity formations between the gas-oxygen torch soldering and infrared ray soldering technique or between the gap distance of 0.3 mm and 0.5 mm. PMID:21264189

  13. Closing the Gap: Opportunities for Distance Education to Benefit Adult Learners in Higher Education

    ERIC Educational Resources Information Center

    Carlsen, A.; Holmberg, C.; Neghina, C.; Owusu-Boampong, A.

    2016-01-01

    Distance education in higher education is a fast-growing and widespread phenomenon. As many adults are unable to participate in on-campus education, distance education offers flexible learning paths that greatly enhance accessibility to higher education. Exploring distance education's potential to increase the participation of adult learners in…

  14. The effect of the gap distance between an atmospheric-pressure plasma jet nozzle and liquid surface on OH and N2 species concentrations

    NASA Astrophysics Data System (ADS)

    Ghimire, Bhagirath; Sornsakdanuphap, Jirapong; Hong, Young June; Uhm, Han Sup; Weltmann, Klaus-Dieter; Choi, Eun Ha

    2017-07-01

    An argon plasma jet at atmospheric pressure was operated at various gap distances between the nozzle of the plasma jet and the water surface in order to study the formation of OH and N2 species in the vicinity of the water surface. Plasma was generated using a 24 kHz sinusoidal power supply at a steady gas flow-rate of 200 sccm. The electron temperature and rotational temperature of gas species were measured using optical emission spectroscopy and found to decrease with increasing gap distance. Meanwhile, the electron density calculated from jet current measurement increased with increasing gap distance. The average OH concentration reduced from 6.10 × 1015 cm-3 to 1.35 × 1015 cm-3, as the gap distance increased from 1 to 4 mm. The 337 nm N2 second positive system studied by optical emission spectroscopy and temporal emission signals increased with increasing gap distance. Plasma activated water was also made from various gap distances in order to confirm the presence of particular reactive oxygen or nitrogen species inside the water. The maximum observed absorbance corresponding to nitrogen oxide was in the spectral range of 230-250 nm from the 4 mm gap distance, while another maximum was recorded in the range of 250-260 nm corresponding to H2O2 from the 1 mm gap distance. Our experimental observations indicate that reactive oxygen and nitrogen species may be generated above the water surface or penetrate into some biological fluids, suggesting that their particular production can be tailored by the variation of the gap distance.

  15. Effects of multilayered graphene on the performance of near-field thermophotovoltaic system at longer vacuum gap distances

    NASA Astrophysics Data System (ADS)

    Lim, Mikyung; Lee, Seung S.; Lee, Bong Jae

    2017-08-01

    The present work aims to enhance the performance of near-field thermophotovoltaic (TPV) system operated at low temperature by introducing multilayered graphene on top of the TPV cell. The multilayered graphene shifts the surface plasmon polariton to the condition where heat flux occurs efficiently at vacuum gap longer than 50 nm. It is found that three-layer graphene can increase the power output by 5.8 times at 50-nm vacuum gap, whereas a monolayer of graphene has a negligible effect at such distance. The fundamental mechanism for the enhancement by the multilayered graphene is explored by analyzing the heat transfer and corresponding photocurrent generation through three modes: propagating, frustrated, and surface modes. Through the detailed analysis, the optimal number of the graphene layers depending on the vacuum gap distance can be predicted. Considering a penetration depth inside the TPV cell, the effect of the width of p-region of the cell on the power output is discussed. It is shown that the change of the width of p-region can either improve or suppress the effect of graphene. The results obtained in this study can facilitate future development of practical TPV system with high performance.

  16. Bridging the Gap--Taking the Distance out of e-Learning

    ERIC Educational Resources Information Center

    Karlsudd, Peter; Tågerud, Yael

    2008-01-01

    In order to promote closer relations between two existing academic environments--on-campus and distance learning--a pedagogical intervention was made aiming to raise the level of competence and awareness among faculty regarding flexible learning and the use of ICT in higher education. The intervention was a process-oriented pedagogical effort…

  17. Bridging the Communication Gap: An Action Science Research Study of Teacher Collaboration in Distance Learning

    ERIC Educational Resources Information Center

    Young, Terrica L.

    2012-01-01

    Rapid change in organizational structure sparked a need in one private school district to design and implement an efficient communication system in distance learning environments. The purpose of this qualitative case study was to improve the collaboration process among teachers and administrators in this highly safeguarded population in a way that…

  18. Closing the Gap between the Inside and the Outside: Interoceptive Sensitivity and Social Distances

    PubMed Central

    Ambrosecchia, Marianna; Gallese, Vittorio

    2013-01-01

    Humans’ ability to represent their body state from within through interoception has been proposed to predict different aspects of human cognition and behaviour. We focused on the possible contribution of interoceptive sensitivity to social behaviour as mediated by adaptive modulation of autonomic response. We, thus, investigated whether interoceptive sensitivity to one's heartbeat predicts participants' autonomic response at different social distances. We measured respiratory sinus arrhythmia (RSA) during either a Social or a Non-social task. In the Social task each participant viewed an experimenter performing a caress-like movement at different distances from their hand. In the Non-social task a metal stick was moved at the same distances from the participant's hand. We found a positive association between interoceptive sensitivity and autonomic response only for the social setting. Moreover, only good heartbeat perceivers showed higher autonomic response 1) in the social compared to the non-social setting, 2) specifically, when the experimenter's hand was moving at boundary of their peripersonal space (20 cm from the participant's hand). Our findings suggest that interoceptive sensitivity might contribute to interindividual differences concerning social attitudes and interpersonal space representation via recruitment of different adaptive autonomic response strategies. PMID:24098397

  19. Mind the gap: a flow instability controlled by particle-surface distance

    NASA Astrophysics Data System (ADS)

    Driscoll, Michelle; Delmotte, Blaise; Youssef, Mena; Sacanna, Stefano; Donev, Aleksandar; Chaikin, Paul

    2016-11-01

    Does a rotating particle always spin in place? Not if that particle is near a surface: rolling leads to translational motion, as well as very strong flows around the particle, even quite far away. These large advective flows strongly couple the motion of neighboring particles, giving rise to strong collective effects in groups of rolling particles. Using a model experimental system, weakly magnetic colloids driven by a rotating magnetic field, we observe that driving a compact group of microrollers leads to a new kind of flow instability. First, an initially uniformly-distributed strip of particles evolves into a shock structure, and then it becomes unstable, emitting fingers with a well-defined wavelength. Using 3D large-scale simulations in tandem with our experiments, we find that the instability wavelength is controlled not by the driving torque or the fluid viscosity, but a geometric parameter: the microroller's distance above the container floor. Furthermore, we find that the instability dynamics can be reproduced using only one ingredient: hydrodynamic interactions near a no-slip boundary.

  20. Label-free measurement of cell-electrode cleft gap distance with high spatial resolution surface plasmon microscopy.

    PubMed

    Toma, Koji; Kano, Hiroshi; Offenhäusser, Andreas

    2014-12-23

    Understanding the interface between cells or tissues and artificial materials is of critical importance for a broad range of areas. For example, in neurotechnology, the interfaces between neurons and external devices create a link between technical and the nervous systems by stimulating or recording from neural tissue. Here, a more effective interface is required to enhance the electrical characteristics of neuronal recordings and stimulations. Up to now, the lack of a systematic characterization of cell-electrode interaction turns out to be the major bottleneck. In this work, we employed a recently developed surface plasmon microscope (SPM) to monitor in real-time the cell-metal interface and to measure in situ the gap distance of the cleft with the spatial resolution reaching to the optical diffraction limit. The SPM allowed determination of the distance of human embryonic kidney 293 cells cultured on gold surfaces coated with various peptides or proteins without any labeling. This method can dramatically simplify the interaction investigation at metal-living cell interface and should be incorporated into systematic characterization methods.

  1. Propagation Distance of the α-Particle-Induced Bystander Effect: The Role of Nuclear Traversal and Gap Junction Communication

    PubMed Central

    Gaillard, Sylvain; Pusset, David; de Toledo, Sonia M.; Fromm, Michel; Azzam, Edouard I.

    2009-01-01

    When cell populations are exposed to low-dose α-particle radiation, a significant fraction of the cells will not be traversed by a radiation track. However, stressful effects occur in both irradiated and bystander cells in the population. Characterizing these effects, and investigating their underlying mechanism(s), is critical to understanding human health risks associated with exposure to α particles. To this end, confluent normal human fibroblast cultures were grown on polyethylene terephthalate foil grafted to an ultrathin solid-state nuclear track detector and exposed under non-perturbing conditions to low-fluence α particles from a broadbeam irradiator. Irradiated and affected bystander cells were localized with micrometer precision. The stress-responsive protein p21Waf1 (also known as CDKN1A) was induced in bystander cells within a 100-µm radius from an irradiated cell. The mean propagation distance ranged from 20 to 40 µm around the intranuclear α-particle impact point, which corresponds to a set of ∼30 cells. Nuclear traversal, induced DNA damage, and gap junction communication were critical contributors to propagation of this stressful effect The strategy described here may be ideal to investigate the size of radiation-affected target and the relative contribution of different cellular organelles to bystander effects induced by energetic particles, which is relevant to radioprotection and cancer radiotherapy. PMID:19580486

  2. Twisted trees and inconsistency of tree estimation when gaps are treated as missing data - The impact of model mis-specification in distance corrections.

    PubMed

    McTavish, Emily Jane; Steel, Mike; Holder, Mark T

    2015-12-01

    Statistically consistent estimation of phylogenetic trees or gene trees is possible if pairwise sequence dissimilarities can be converted to a set of distances that are proportional to the true evolutionary distances. Susko et al. (2004) reported some strikingly broad results about the forms of inconsistency in tree estimation that can arise if corrected distances are not proportional to the true distances. They showed that if the corrected distance is a concave function of the true distance, then inconsistency due to long branch attraction will occur. If these functions are convex, then two "long branch repulsion" trees will be preferred over the true tree - though these two incorrect trees are expected to be tied as the preferred true. Here we extend their results, and demonstrate the existence of a tree shape (which we refer to as a "twisted Farris-zone" tree) for which a single incorrect tree topology will be guaranteed to be preferred if the corrected distance function is convex. We also report that the standard practice of treating gaps in sequence alignments as missing data is sufficient to produce non-linear corrected distance functions if the substitution process is not independent of the insertion/deletion process. Taken together, these results imply inconsistent tree inference under mild conditions. For example, if some positions in a sequence are constrained to be free of substitutions and insertion/deletion events while the remaining sites evolve with independent substitutions and insertion/deletion events, then the distances obtained by treating gaps as missing data can support an incorrect tree topology even given an unlimited amount of data.

  3. "Mind the Gap": The Application of a Conceptual Model to Investigate Distance Learners' Expectations and Perceptions of Induction

    ERIC Educational Resources Information Center

    Forrester, Gillian; Parkinson, Gillian

    2006-01-01

    Increasingly, emphasis is being placed on meeting students' learning and support needs in higher education, initially through the induction process. Academic staff have limited contact with distance students, compared with campus-based students, and thus may not fully appreciate their particular expectations and perceptions. This study sought to…

  4. New Communication Practices, Identity and the Psychological Gap: The Affective Function of E-mail on a Distance Doctoral Programme.

    ERIC Educational Resources Information Center

    Sunderland, Jane

    2002-01-01

    Examined e-mail messages sent by Romanian Ph.D. students over the first 2 years of a (largely) distance education program based in the United Kingdom. Found that participants used e-mail to obtain support, inscribe their multiple identities within their messages, and adapt the medium for their own needs; these uses have particular value for…

  5. The effects of gaseous bubble composition and gap distance on the characteristics of nanosecond discharges in distilled water

    NASA Astrophysics Data System (ADS)

    Hamdan, Ahmad; Cha, Min Suk

    2016-06-01

    Electric discharge in liquids with bubbles can reduce the energy consumption, which increases treatment efficiency. We present an experimental study of nanosecond discharges in distilled water bubbled with the monoatomic gas argon and with the polyatomic gases methane, carbon dioxide, and propane. We monitor the time evolution of the voltage and current waveforms, and calculate the injected charges to characterize the discharge. We establish a relationship between the injected charges and the shape of the plasma by time-resolved imaging to find that increasing the size of the gap reduces the injected charges. Moreover, we determine the plasma characteristics, including electron density, excitation temperatures (for atoms and ions), and rotational temperature of the OH and C2 radicals found in the plasma. Our space- and time-averaged measurements allow us to propose a spatial distribution of the plasma that is helpful for understanding the plasma dynamics necessary to develop and optimize applications based on nanosecond discharges in bubbled liquids.

  6. Disrupting the Implementation Gap with Digital Technology in Healthcare Distance Education: Critical Insights from an e-Mentoring Intensional Network Practitioner Research Project

    ERIC Educational Resources Information Center

    Singh, Gurmit

    2013-01-01

    Effective professional distance education is urgently needed to develop a well-trained workforce and improve impact on healthcare. However, distance education initiatives have had mixed results in improving practice. Often, successful implementation fails to leverage insights on the social and emergent nature of learning in networks. This paper…

  7. Disrupting the Implementation Gap with Digital Technology in Healthcare Distance Education: Critical Insights from an e-Mentoring Intensional Network Practitioner Research Project

    ERIC Educational Resources Information Center

    Singh, Gurmit

    2013-01-01

    Effective professional distance education is urgently needed to develop a well-trained workforce and improve impact on healthcare. However, distance education initiatives have had mixed results in improving practice. Often, successful implementation fails to leverage insights on the social and emergent nature of learning in networks. This paper…

  8. Closing the Performance Gap.

    ERIC Educational Resources Information Center

    Riggins, Cheryl G.

    2002-01-01

    Describes how the principal of a K-2, 400-student suburban elementary school near Flint, Michigan, worked with her staff and superintendent to develop and implement a strategic plan to close the student achievement gap. Reports significant improvement in reading and math scores after 1 year. (PKP)

  9. Closing the Performance Gap.

    ERIC Educational Resources Information Center

    Riggins, Cheryl G.

    2002-01-01

    Describes how the principal of a K-2, 400-student suburban elementary school near Flint, Michigan, worked with her staff and superintendent to develop and implement a strategic plan to close the student achievement gap. Reports significant improvement in reading and math scores after 1 year. (PKP)

  10. Simulation Distances

    NASA Astrophysics Data System (ADS)

    Černý, Pavol; Henzinger, Thomas A.; Radhakrishna, Arjun

    Boolean notions of correctness are formalized by preorders on systems. Quantitative measures of correctness can be formalized by real-valued distance functions between systems, where the distance between implementation and specification provides a measure of "fit" or "desirability." We extend the simulation preorder to the quantitative setting, by making each player of a simulation game pay a certain price for her choices. We use the resulting games with quantitative objectives to define three different simulation distances. The correctness distance measures how much the specification must be changed in order to be satisfied by the implementation. The coverage distance measures how much the implementation restricts the degrees of freedom offered by the specification. The robustness distance measures how much a system can deviate from the implementation description without violating the specification. We consider these distances for safety as well as liveness specifications. The distances can be computed in polynomial time for safety specifications, and for liveness specifications given by weak fairness constraints. We show that the distance functions satisfy the triangle inequality, that the distance between two systems does not increase under parallel composition with a third system, and that the distance between two systems can be bounded from above and below by distances between abstractions of the two systems. These properties suggest that our simulation distances provide an appropriate basis for a quantitative theory of discrete systems. We also demonstrate how the robustness distance can be used to measure how many transmission errors are tolerated by error correcting codes.

  11. Distance Learning.

    ERIC Educational Resources Information Center

    Orey, Michael; Koenecke, Lynne; Snider, Richard C.; Perkins, Ross A.; Holmes, Glen A.; Lockee, Barbara B.; Moller, Leslie A.; Harvey, Douglas; Downs, Margaret; Godshalk, Veronica M.

    2003-01-01

    Contains four articles covering trends and issues on distance learning including: the experience of two learners learning via the Internet; a systematic approach to determining the scalability of a distance education program; identifying factors that affect learning community development and performance in asynchronous distance education; and…

  12. Gap junctions.

    PubMed

    Goodenough, Daniel A; Paul, David L

    2009-07-01

    Gap junctions are aggregates of intercellular channels that permit direct cell-cell transfer of ions and small molecules. Initially described as low-resistance ion pathways joining excitable cells (nerve and muscle), gap junctions are found joining virtually all cells in solid tissues. Their long evolutionary history has permitted adaptation of gap-junctional intercellular communication to a variety of functions, with multiple regulatory mechanisms. Gap-junctional channels are composed of hexamers of medium-sized families of integral proteins: connexins in chordates and innexins in precordates. The functions of gap junctions have been explored by studying mutations in flies, worms, and humans, and targeted gene disruption in mice. These studies have revealed a wide diversity of function in tissue and organ biology.

  13. Gap Junctions

    PubMed Central

    Goodenough, Daniel A.; Paul, David L.

    2009-01-01

    Gap junctions are aggregates of intercellular channels that permit direct cell–cell transfer of ions and small molecules. Initially described as low-resistance ion pathways joining excitable cells (nerve and muscle), gap junctions are found joining virtually all cells in solid tissues. Their long evolutionary history has permitted adaptation of gap-junctional intercellular communication to a variety of functions, with multiple regulatory mechanisms. Gap-junctional channels are composed of hexamers of medium-sized families of integral proteins: connexins in chordates and innexins in precordates. The functions of gap junctions have been explored by studying mutations in flies, worms, and humans, and targeted gene disruption in mice. These studies have revealed a wide diversity of function in tissue and organ biology. PMID:20066080

  14. Gap junctions.

    PubMed

    Nielsen, Morten Schak; Axelsen, Lene Nygaard; Sorgen, Paul L; Verma, Vandana; Delmar, Mario; Holstein-Rathlou, Niels-Henrik

    2012-07-01

    Gap junctions are essential to the function of multicellular animals, which require a high degree of coordination between cells. In vertebrates, gap junctions comprise connexins and currently 21 connexins are known in humans. The functions of gap junctions are highly diverse and include exchange of metabolites and electrical signals between cells, as well as functions, which are apparently unrelated to intercellular communication. Given the diversity of gap junction physiology, regulation of gap junction activity is complex. The structure of the various connexins is known to some extent; and structural rearrangements and intramolecular interactions are important for regulation of channel function. Intercellular coupling is further regulated by the number and activity of channels present in gap junctional plaques. The number of connexins in cell-cell channels is regulated by controlling transcription, translation, trafficking, and degradation; and all of these processes are under strict control. Once in the membrane, channel activity is determined by the conductive properties of the connexin involved, which can be regulated by voltage and chemical gating, as well as a large number of posttranslational modifications. The aim of the present article is to review our current knowledge on the structure, regulation, function, and pharmacology of gap junctions. This will be supported by examples of how different connexins and their regulation act in concert to achieve appropriate physiological control, and how disturbances of connexin function can lead to disease. © 2012 American Physiological Society. Compr Physiol 2:1853-1872, 2012.

  15. Gap Junctions

    PubMed Central

    Nielsen, Morten Schak; Axelsen, Lene Nygaard; Sorgen, Paul L.; Verma, Vandana; Delmar, Mario; Holstein-Rathlou, Niels-Henrik

    2013-01-01

    Gap junctions are essential to the function of multicellular animals, which require a high degree of coordination between cells. In vertebrates, gap junctions comprise connexins and currently 21 connexins are known in humans. The functions of gap junctions are highly diverse and include exchange of metabolites and electrical signals between cells, as well as functions, which are apparently unrelated to intercellular communication. Given the diversity of gap junction physiology, regulation of gap junction activity is complex. The structure of the various connexins is known to some extent; and structural rearrangements and intramolecular interactions are important for regulation of channel function. Intercellular coupling is further regulated by the number and activity of channels present in gap junctional plaques. The number of connexins in cell-cell channels is regulated by controlling transcription, translation, trafficking, and degradation; and all of these processes are under strict control. Once in the membrane, channel activity is determined by the conductive properties of the connexin involved, which can be regulated by voltage and chemical gating, as well as a large number of posttranslational modifications. The aim of the present article is to review our current knowledge on the structure, regulation, function, and pharmacology of gap junctions. This will be supported by examples of how different connexins and their regulation act in concert to achieve appropriate physiological control, and how disturbances of connexin function can lead to disease. © 2012 American Physiological Society. Compr Physiol 2:1981-2035, 2012. PMID:23723031

  16. Gap junctions.

    PubMed

    Shimizu, Kazumichi; Stopfer, Mark

    2013-12-02

    In vertebrates and invertebrates, signaling among neurons is most commonly mediated by chemical synapses. At these synapses neurotransmitter released by presynaptic neurons is detected by receptors on the postsynaptic neurons, leading to an influx of ions through the receptors themselves or through channels activated by intracellular signaling downstream of the receptors. But neurons can communicate with each other in a more direct way, by passing signals composed of small molecules and ions through pores called gap junctions. Gap junctions that transmit electrical signals are called electrical synapses. Unlike most chemical synapses, electrical synapses interact through axon-to-axon or dendrite-to-dendrite contacts. Found throughout the nervous system, they are probably best known for linking the relatively few inhibitory, GABAergic, neurons into large, effective networks within vertebrate brains. They are particularly important early in development before the formation of most chemical synapses, but recent work shows gap junctions play important roles in the adult nervous system, too. Gap junctions are sometimes thought to be mere passageways between cells. But, as recent work shows, their properties can be complex and surprising. Gap junctions help generate, propagate, and regulate neural oscillations, can filter electrical signals, and can be modulated in a variety of ways. Here we discuss recent work highlighting the diversity and importance of gap junctions throughout the nervous system. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. [Distance Education.

    ERIC Educational Resources Information Center

    Wallace, Teri, Ed.; Weatherman, Dick, Ed.

    1995-01-01

    This newsletter theme issue on distance education serving individuals with disabilities considers historical developments, technology, staff training strategies, and staff training materials. It is noted that improving access to training for staff members can improve the quality of services for individuals with disabilities. The following articles…

  18. Development of a Distance Education Network in the OECS. Feasibility Study. Filling a Gap in a Way that Makes Sense. Report of a Consultancy to the Commonwealth of Learning.

    ERIC Educational Resources Information Center

    Roberts, Judy

    A study was conducted to determine the feasibility of a distance education network in the Eastern Caribbean. Two types of consultations were completed: a brief site survey of four Eastern Caribbean states (Grenada, Dominica, Antigua, and Saint Lucia) and a workshop in Saint Lucia to which education officials from government agencies and higher…

  19. Who Graduates from Irish Distance University Education?

    ERIC Educational Resources Information Center

    Delaney, Lorraine

    2015-01-01

    This paper outlines results from an online survey of recent distance graduates. The study, based in Dublin City University (DCU) addresses a gap in the research on this cohort of graduates. Findings indicate that distance graduates are primarily from lower socio economic backgrounds, a group largely under-represented in full-time university…

  20. Who Graduates from Irish Distance University Education?

    ERIC Educational Resources Information Center

    Delaney, Lorraine

    2015-01-01

    This paper outlines results from an online survey of recent distance graduates. The study, based in Dublin City University (DCU) addresses a gap in the research on this cohort of graduates. Findings indicate that distance graduates are primarily from lower socio economic backgrounds, a group largely under-represented in full-time university…

  1. Band gaps in bubble phononic crystals

    NASA Astrophysics Data System (ADS)

    Leroy, V.; Bretagne, A.; Lanoy, M.; Tourin, A.

    2016-12-01

    We investigate the interaction between Bragg and hybridization effects on the band gap properties of bubble phononic crystals. These latter consist of air cavities periodically arranged in an elastomer matrix and are fabricated using soft-lithography techniques. Their transmission properties are affected by Bragg effects due to the periodicity of the structure as well as hybridization between the propagating mode of the embedding medium and bubble resonance. The hybridization gap survives disorder while the Bragg gap requires a periodic distribution of bubbles. The distance between two bubble layers can be tuned to make the two gaps overlap or to create a transmission peak in the hybridization gap.

  2. Pan Alone in the Gap

    NASA Image and Video Library

    2014-09-08

    Saturn's innermost moon Pan orbits the giant planet seemingly alone in a ring gap its own gravity creates. Pan (17 miles, or 28 kilometers across) maintains the Encke Gap in Saturn's A ring by gravitationally nudging the ring particles back into the rings when they stray in the gap. Scientists think similar processes might be at work as forming planets clear gaps in the circumstellar disks from which they form. This view looks toward the sunlit side of the rings from about 38 degrees above the ringplane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on May 3, 2014. The view was acquired at a distance of approximately 2 million miles (3.2 million kilometers) from Pan and at a Sun-Pan-spacecraft, or phase, angle of 56 degrees. Image scale is 12 miles (19 kilometers) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA18281

  3. Pneumatic gap sensor and method

    DOEpatents

    Bagdal, K.T.; King, E.L.; Follstaedt, D.W.

    1992-03-03

    An apparatus and method for monitoring and maintaining a predetermined width in the gap between a casting nozzle and a casting wheel, wherein the gap is monitored by means of at least one pneumatic gap sensor. The pneumatic gap sensor is mounted on the casting nozzle in proximity to the casting surface and is connected by means of a tube to a regulator and a transducer. The regulator provides a flow of gas through a restictor to the pneumatic gap sensor, and the transducer translates the changes in the gas pressure caused by the proximity of the casting wheel to the pneumatic gap sensor outlet into a signal intelligible to a control device. The relative positions of the casting nozzle and casting wheel can thereby be selectively adjusted to continually maintain a predetermined distance between their adjacent surfaces. The apparatus and method enables accurate monitoring of the actual casting gap in a simple and reliable manner resistant to the extreme temperatures and otherwise hostile casting environment. 6 figs.

  4. Pneumatic gap sensor and method

    DOEpatents

    Bagdal, Karl T.; King, Edward L.; Follstaedt, Donald W.

    1992-01-01

    An apparatus and method for monitoring and maintaining a predetermined width in the gap between a casting nozzle and a casting wheel, wherein the gap is monitored by means of at least one pneumatic gap sensor. The pneumatic gap sensor is mounted on the casting nozzle in proximity to the casting surface and is connected by means of a tube to a regulator and a transducer. The regulator provides a flow of gas through a restictor to the pneumatic gap sensor, and the transducer translates the changes in the gas pressure caused by the proximity of the casting wheel to the pneumatic gap sensor outlet into a signal intelligible to a control device. The relative positions of the casting nozzle and casting wheel can thereby be selectively adjusted to continually maintain a predetermined distance between their adjacent surfaces. The apparatus and method enables accurate monitoring of the actual casting gap in a simple and reliable manner resistant to the extreme temperatures and otherwise hostile casting environment.

  5. On distance variation effects on graphene bilayers

    NASA Astrophysics Data System (ADS)

    Naji, S.; Bhihi, M.; Labrim, H.; Belhaj, A.; Benyoussef, A.; El Kenz, A.; Loulidi, M.

    2014-06-01

    The opening of the energy gap and the total energy of the graphene-like bilayers are investigated using ab initio calculations. The studied model consists of a static single layer of graphene interacting with an extra dynamic one placed at a varying vertical distance d in the (AB) stacking arrangement. The effects of the vertical distance variation on the energy gap and the total energy of the system are discussed first. Starting from a distance around the van der Waals length, the energy gap does not depend on the vertical distance variation and the system exhibits graphene-like properties with minor deformations in the lattice size parameter and the energy dispersion behaviour around K points. However, it has been shown that the diagonal distance variation of the graphene-like bilayer modifies the electronic structure properties. This modification depends on an intermediate stacking arrangement between the (AA) and the (AB) configurations. It has been shown that the diagonal distance variation has an influence on the states of pz electrons in the (AB) arrangement and it can be explored to open the energy gap.

  6. Defining Distance Learning and Distance Education.

    ERIC Educational Resources Information Center

    King, Frederick B.; Young, Michael F.; Drivere-Richmond, Kelly; Schrader, P. G.

    2001-01-01

    This paper offers precise definitions of distance learning and distance education, and their interrelationship. First, a single definition of learning is proposed, and then the concept of learning is broken down into three subcategories: instruction, exploration, and serendipity. Each is defined and the concepts of distance learning and distance…

  7. Small Multiples with Gaps.

    PubMed

    Meulemans, Wouter; Dykes, Jason; Slingsby, Aidan; Turkay, Cagatay; Wood, Jo

    2017-01-01

    Small multiples enable comparison by providing different views of a single data set in a dense and aligned manner. A common frame defines each view, which varies based upon values of a conditioning variable. An increasingly popular use of this technique is to project two-dimensional locations into a gridded space (e.g. grid maps), using the underlying distribution both as the conditioning variable and to determine the grid layout. Using whitespace in this layout has the potential to carry information, especially in a geographic context. Yet, the effects of doing so on the spatial properties of the original units are not understood. We explore the design space offered by such small multiples with gaps. We do so by constructing a comprehensive suite of metrics that capture properties of the layout used to arrange the small multiples for comparison (e.g. compactness and alignment) and the preservation of the original data (e.g. distance, topology and shape). We study these metrics in geographic data sets with varying properties and numbers of gaps. We use simulated annealing to optimize for each metric and measure the effects on the others. To explore these effects systematically, we take a new approach, developing a system to visualize this design space using a set of interactive matrices. We find that adding small amounts of whitespace to small multiple arrays improves some of the characteristics of 2D layouts, such as shape, distance and direction. This comes at the cost of other metrics, such as the retention of topology. Effects vary according to the input maps, with degree of variation in size of input regions found to be a factor. Optima exist for particular metrics in many cases, but at different amounts of whitespace for different maps. We suggest multiple metrics be used in optimized layouts, finding topology to be a primary factor in existing manually-crafted solutions, followed by a trade-off between shape and displacement. But the rich range of possible

  8. Groundlayer vegetation gradients across oak woodland canopy gaps

    USGS Publications Warehouse

    Pavlovic, N.B.; Grundel, R.; Sluis, W.

    2006-01-01

    Frequency of groundlayer plants was measured across oak woodland canopy gaps at three sites in northwest Indiana to examine how vegetation varied with gap size, direction along the gap edge, and microhabitat. Microhabitats were defined as under the canopy adjacent to the gap, along the gap edge, and within the gap. Gap-sites consisted of gaps plus adjacent tree canopy. Gaps were classified as small (16 ± 1 m2), medium (97 ± 8), and large (310 ± 32). Neither richness nor diversity differed among microhabitats, gap sizes, or edges. Similarity between microhabitats wthin a gap-site increased as the distance between plots decreased and as the difference in PAR decreased, the latter explaining twice the variation in percent dissimilarity compared to Mg concentration, A horizon depth, and litter cover. Diervilla lonicera, Frageria virginiana, Helianthus divaricatus, Polygonatum pubescens, Quercus velutina, Smilacena stellata, and Tradescantia ohiensis decreased, whileTephrosia virginiana and legumes increased in frequency, from canopy to gap, and C4 grasses peaked at the gap edge, independent of gap size. Additional species frequency varied across the microhabitat gradient within specific sites. Sorghastrum nutans was three times more frequent in gaps at large sites than elsewhere. The vegetation in medium-sized gap-sites was more variable than within small and large gap-sites, suggesting greater environmental heterogeneity at that scale. Within gap-sites, vegetation was more heterogeneous within edges and canopies than in gaps. Edges were more similar in composition to gaps than to canopy groundlayer within gap-sites. Few species varied significantly in frequency around the gap edge. The oak woodland groundlayer on sandy substrates can be characterized as a mosaic of forb dominated vegetation that varies across light gradients associated with canopy gaps, transitioning to islands of grassland vegetation when gaps exceed 160 m2.

  9. Optimum viewing distance for target acquisition

    NASA Astrophysics Data System (ADS)

    Holst, Gerald C.

    2015-05-01

    Human visual system (HVS) "resolution" (a.k.a. visual acuity) varies with illumination level, target characteristics, and target contrast. For signage, computer displays, cell phones, and TVs a viewing distance and display size are selected. Then the number of display pixels is chosen such that each pixel subtends 1 min-1. Resolution of low contrast targets is quite different. It is best described by Barten's contrast sensitivity function. Target acquisition models predict maximum range when the display pixel subtends 3.3 min-1. The optimum viewing distance is nearly independent of magnification. Noise increases the optimum viewing distance.

  10. Distance Education Council.

    ERIC Educational Resources Information Center

    Indira Gandhi National Open University, New Delhi (India). Distance Education Council.

    Since its inception in India in 1962, distance education has grown in popularity. The Distance Education Council (DEC) directs distance learning within India's higher education system. The DEC's promotion, coordination, and maintenance of standards for distance education are its three major roles. Its initiatives include grants, support for…

  11. Facilitating Distance Education.

    ERIC Educational Resources Information Center

    Rossman, Mark H., Ed.; Rossman, Maxine E., Ed.

    1995-01-01

    This collection of articles on distance learning reflects the perspectives and concerns of the learner and the facilitator of learning in distance education setting. Eight chapters are included: (1) "The Evolution and Advantages of Distance Education" (John E. Cantelon) traces the history of distance education and demonstrates how it transcends…

  12. Distance Education in Turkey

    ERIC Educational Resources Information Center

    Ruzgar, Nursel Selver

    2004-01-01

    Many countries of the world are using distance education with various ways, by INTERNET, by post and by TV. In this work, development of distance education in Turkey has been presented from the beginning. After discussing types and applications for different levels of distance education in Turkey, the distance education was given in the cultural…

  13. Facilitating Distance Education.

    ERIC Educational Resources Information Center

    Rossman, Mark H., Ed.; Rossman, Maxine E., Ed.

    1995-01-01

    This collection of articles on distance learning reflects the perspectives and concerns of the learner and the facilitator of learning in distance education setting. Eight chapters are included: (1) "The Evolution and Advantages of Distance Education" (John E. Cantelon) traces the history of distance education and demonstrates how it transcends…

  14. Training for Distance Teaching through Distance Learning.

    ERIC Educational Resources Information Center

    Cadorath, Jill; Harris, Simon; Encinas, Fatima

    2002-01-01

    Describes a mixed-mode bachelor degree course in English language teaching at the Universidad Autonoma de Puebla (Mexico) that was designed to help practicing teachers write appropriate distance education materials by giving them the experience of being distance students. Includes a course outline and results of a course evaluation. (Author/LRW)

  15. Training for Distance Teaching through Distance Learning.

    ERIC Educational Resources Information Center

    Cadorath, Jill; Harris, Simon; Encinas, Fatima

    2002-01-01

    Describes a mixed-mode bachelor degree course in English language teaching at the Universidad Autonoma de Puebla (Mexico) that was designed to help practicing teachers write appropriate distance education materials by giving them the experience of being distance students. Includes a course outline and results of a course evaluation. (Author/LRW)

  16. Electronic gap sensor and method

    DOEpatents

    Williams, R.S.; King, E.L.; Campbell, S.L.

    1991-08-06

    Disclosed are an apparatus and method for regulating the gap between a casting nozzle and a casting wheel in which the gap between the casting nozzle and the casting wheel is monitored by means of at least one sensing element protruding from the face of the casting nozzle. The sensing element is preferably connected to a voltage source and the casting wheel grounded. When the sensing element contacts the casting wheel, an electric circuit is completed. The completion of the circuit can be registered by an indicator, and the presence or absence of a completed circuit indicates the relative position of the casting nozzle to the casting wheel. The relative positions of the casting nozzle and casting wheel can thereby be selectively adjusted to continually maintain a predetermined distance between their adjacent surfaces. 5 figures.

  17. Electronic gap sensor and method

    DOEpatents

    Williams, Robert S.; King, Edward L.; Campbell, Steven L.

    1991-01-01

    An apparatus and method for regulating the gap between a casting nozzle and a casting wheel in which the gap between the casting nozzle and the casting wheel is monitored by means of at least one sensing element protruding from the face of the casting nozzle. The sensing element is preferably connected to a voltage source and the casting wheel grounded. When the sensing element contacts the casting wheel, an electric circuit is completed. The completion of the circuit can be registered by an indicator, and the presence or absence of a completed circuit indicates the relative position of the casting nozzle to the casting wheel. The relative positions of the casting nozzle and casting wheel can thereby be selectively adjusted to continually maintain a predetermined distance between their adjacent surfaces.

  18. Going the Distance.

    ERIC Educational Resources Information Center

    Leno, Arthur J.

    2003-01-01

    Describes the development and implementation of the distance education program at Peirce College. This Internet-mediated distance learning program focuses on practical fields of study, drawing on the college's strengths in business administration, information technology, and paralegal studies. (SLD)

  19. The Distance Learning of Foreign Languages: A Research Agenda

    ERIC Educational Resources Information Center

    White, Cynthia

    2014-01-01

    Research into the distance learning of languages is now established as a significant avenue of enquiry in language teaching, with evident research trajectories in several domains. This article selects and analyses significant areas of investigation in distance language learning and teaching to identify new and emerging gaps, along with research…

  20. The Distance Learning of Foreign Languages: A Research Agenda

    ERIC Educational Resources Information Center

    White, Cynthia

    2014-01-01

    Research into the distance learning of languages is now established as a significant avenue of enquiry in language teaching, with evident research trajectories in several domains. This article selects and analyses significant areas of investigation in distance language learning and teaching to identify new and emerging gaps, along with research…

  1. Drop short control of electrode gap

    DOEpatents

    Fisher, Robert W.; Maroone, James P.; Tipping, Donald W.; Zanner, Frank J.

    1986-01-01

    During vacuum consumable arc remelting the electrode gap between a consumable electrode and a pool of molten metal is difficult to control. The present invention monitors drop shorts by detecting a decrease in the voltage between the consumable electrode and molten pool. The drop shorts and their associated voltage reductions occur as repetitive pulses which are closely correlated to the electrode gap. Thus, the method and apparatus of the present invention controls electrode gap based upon drop shorts detected from the monitored anode-cathode voltage. The number of drop shorts are accumulated, and each time the number of drop shorts reach a predetermined number, the average period between drop shorts is calculated from this predetermined number and the time in which this number is accumulated. This average drop short period is used in a drop short period electrode gap model which determines the actual electrode gap from the drop short. The actual electrode gap is then compared with a desired electrode gap which is selected to produce optimum operating conditions and the velocity of the consumable error is varied based upon the gap error. The consumable electrode is driven according to any prior art system at this velocity. In the preferred embodiment, a microprocessor system is utilized to perform the necessary calculations and further to monitor the duration of each drop short. If any drop short exceeds a preset duration period, the consumable electrode is rapidly retracted a predetermined distance to prevent bonding of the consumable electrode to the molten remelt.

  2. Theme: Distance Education.

    ERIC Educational Resources Information Center

    Whittington, M. Susie, Ed.; And Others

    1994-01-01

    Includes "Next Best Thing to Being There" (Whittington); "Taking the Distance out of Distance Education" (Miller, King); "Preparing a Course for Distance Delivery" (Newcomb); "Team Teaching via Two-Way Interactive Video" (Nichols, Trout); "Using the Ag Ed Network" (Peal); "Student's Perspective" (Schoellhorn); "Need for Instruction in Agriculture…

  3. Going the Distance

    ERIC Educational Resources Information Center

    Waters, John K.

    2012-01-01

    Whoever said "Distance education begins in the 10th row" was taking a jab at the comatose kids at the back of his classroom, but the comment also taps into the old image of distance learners as disengaged themselves. That was then. Today, distance-learning programs are booming, in part due to demographic realities but also because recent advances…

  4. Making Distance Education Borderless.

    ERIC Educational Resources Information Center

    Srisa-An, Wichit

    1997-01-01

    Begins with a tribute to Professor G. Ram Reddy (founder of Indira Gandhi National Open University), then focuses on enhancing the role of open universities in providing borderless distance education. Highlights include the need for open distance-education; philosophy and vision; the distance teaching system; the role of information technology;…

  5. Flows of gas through a protoplanetary gap.

    PubMed

    Casassus, Simon; van der Plas, Gerrit; Sebastian Perez, M; Dent, William R F; Fomalont, Ed; Hagelberg, Janis; Hales, Antonio; Jordán, Andrés; Mawet, Dimitri; Ménard, Francois; Wootten, Al; Wilner, David; Hughes, A Meredith; Schreiber, Matthias R; Girard, Julien H; Ercolano, Barbara; Canovas, Hector; Román, Pablo E; Salinas, Vachail

    2013-01-10

    The formation of gaseous giant planets is thought to occur in the first few million years after stellar birth. Models predict that the process produces a deep gap in the dust component (shallower in the gas). Infrared observations of the disk around the young star HD 142527 (at a distance of about 140 parsecs from Earth) found an inner disk about 10 astronomical units (AU) in radius (1 AU is the Earth-Sun distance), surrounded by a particularly large gap and a disrupted outer disk beyond 140 AU. This disruption is indicative of a perturbing planetary-mass body at about 90 AU. Radio observations indicate that the bulk mass is molecular and lies in the outer disk, whose continuum emission has a horseshoe morphology. The high stellar accretion rate would deplete the inner disk in less than one year, and to sustain the observed accretion matter must therefore flow from the outer disk and cross the gap. In dynamical models, the putative protoplanets channel outer-disk material into gap-crossing bridges that feed stellar accretion through the inner disk. Here we report observations of diffuse CO gas inside the gap, with denser HCO(+) gas along gap-crossing filaments. The estimated flow rate of the gas is in the range of 7 × 10(-9) to 2 × 10(-7) solar masses per year, which is sufficient to maintain accretion onto the star at the present rate.

  6. Flows of gas through a protoplanetary gap

    NASA Astrophysics Data System (ADS)

    Casassus, Simon; van der Plas, Gerrit; M, Sebastian Perez; Dent, William R. F.; Fomalont, Ed; Hagelberg, Janis; Hales, Antonio; Jordán, Andrés; Mawet, Dimitri; Ménard, Francois; Wootten, Al; Wilner, David; Hughes, A. Meredith; Schreiber, Matthias R.; Girard, Julien H.; Ercolano, Barbara; Canovas, Hector; Román, Pablo E.; Salinas, Vachail

    2013-01-01

    The formation of gaseous giant planets is thought to occur in the first few million years after stellar birth. Models predict that the process produces a deep gap in the dust component (shallower in the gas). Infrared observations of the disk around the young star HD 142527 (at a distance of about 140 parsecs from Earth) found an inner disk about 10 astronomical units (AU) in radius (1 AU is the Earth-Sun distance), surrounded by a particularly large gap and a disrupted outer disk beyond 140 AU. This disruption is indicative of a perturbing planetary-mass body at about 90 AU. Radio observations indicate that the bulk mass is molecular and lies in the outer disk, whose continuum emission has a horseshoe morphology. The high stellar accretion rate would deplete the inner disk in less than one year, and to sustain the observed accretion matter must therefore flow from the outer disk and cross the gap. In dynamical models, the putative protoplanets channel outer-disk material into gap-crossing bridges that feed stellar accretion through the inner disk. Here we report observations of diffuse CO gas inside the gap, with denser HCO+ gas along gap-crossing filaments. The estimated flow rate of the gas is in the range of 7 × 10-9 to 2 × 10-7 solar masses per year, which is sufficient to maintain accretion onto the star at the present rate.

  7. Anion Gap Blood Test

    MedlinePlus

    ... Why do I need an anion gap blood test? Your health care provider may have ordered an anion gap blood ... which is a blood test. During a blood test, a health care professional uses a small needle to take a ...

  8. Behind the Pay Gap

    ERIC Educational Resources Information Center

    Dey, Judy Goldberg; Hill, Catherine

    2007-01-01

    Women have made remarkable gains in education during the past three decades, yet these achievements have resulted in only modest improvements in pay equity. The gender pay gap has become a fixture of the U.S. workplace and is so ubiquitous that many simply view it as normal. "Behind the Pay Gap" examines the gender pay gap for college graduates.…

  9. Distance Education and Women Empowerment: The Women Who Dared at Distance Learning Institute

    ERIC Educational Resources Information Center

    Okunuga, A. O.

    2011-01-01

    In the past, the African female child had always been denied formal education due to various cultural and social prejudices. Distance education has been employed by numerous women, who had earlier thus been deprived, to bridge the educational gap between males and females in the country. These are mature females, of which the majority (54%) are…

  10. Ab initio approach for gap plasmonics

    NASA Astrophysics Data System (ADS)

    Hohenester, Ulrich; Draxl, Claudia

    2016-10-01

    Gap plasmonics deals with the properties of surface plasmons in the narrow region between two metallic nanoparticles forming the gap. For subnanometer gap distances, electrons can tunnel between the nanoparticles, leading to the emergence of novel charge-transfer plasmons. These are conveniently described within the quantum corrected model by introducing an artificial material with a tunnel conductivity inside the gap region. Here we develop a methodology for computing such tunnel conductivities within the first-principles framework of density functional theory and apply our approach to a jellium model representative for sodium. We show that the frequency dependence of the tunnel conductivity at infrared and optical frequencies can be significantly more complicated than previously thought.

  11. Confined PBX 9501 gap reinitiation studies

    SciTech Connect

    Salyer, Terry R; Hill, Larry G; Lam, Kin

    2009-01-01

    For explosive systems that exhibit gaps or cracks between their internal components (either by design or mechanical failure), measurable time delays exist for detonation waves crossing them. Reinitiation across such gaps is dependent on the type of explosive, gap width, gap morphology, confinement, and temperature effects. To examine this reinitiation effect, a series of tests has been conducted to measure the time delay across a prescribed gap within an 'infinitely' confined PBX 9501 system. Detonation breakout along the explosive surface is measured with a streak camera, and flow features are examined during reinitiation near the gap. Such tests allow for quantitative determination of the time delay corresponding to the time of initiation across a given gap oriented normal to the direction of the detonation wave. Measured time delays can be compared with numerical calculations, making it possible to validate initiation models as well as estimate detonation run-up distances. Understanding this reinitiation behavior is beneficial for the design and evaluation of explosive systems that require precision timing and performance.

  12. The Extragalactic Distance Scale

    NASA Astrophysics Data System (ADS)

    Livio, Mario; Donahue, Megan; Panagia, Nino

    1997-07-01

    Participants; Preface; Foreword; Early history of the distance scale problem, S. van den Bergh; Cosmology: From Hubble to HST, M. S. Turner; Age constraints nucleocosmochronology, J. Truran; The ages of globular clusters, P. Demarque; The linearity of the Hubble flow M. Postman; Gravitational lensing and the extragalactic distance scale, R. D. Blandford andT . Kundic; Using the cosmic microwave background to constrain the Hubble constant A. Lasenby and T M. Jones; Cepheids as distance indicators, N. R. Tanvir; The I-band Tully-Fisher relation and the Hubble constant, R. Giovanell; The calibration of type 1a supernovae as standard candles, A. Saha; Focusing in on the Hubble constant, G. A. Tammann & M. Federspiel; Interim report on the calibration of the Tully-Fisher relation in the HST Key Project to measure the Hubble constant, J. Mould et al.; Hubble Space Telescope Key Project on the extragalactic distance scale, W. L. Freedman, B. F. Madore and T R. C. Kennicutt; Novae as distance indicators, M. Livio; Verifying the planetary nebula luminosity function method, G. H. Jacoby; On the possible use of radio supernovae for distance determinations, K. W. Weiler et al.; Post-AGB stars as standard candles, H. Bond; Helium core flash at the tip of the red giant branch: a population II distance indicator, B. F. Madore, W. L. Freedman and T S. Sakai; Globular clusters as distance indicators, B. C. Whitmore; Detached eclipsing binaries as primary distance and age indicators, B. Paczynski; Light echoes: geometric measurement of galaxy distances, W. B. Sparks; The SBF survey of galaxy distances J. L. Tonry; Extragalactic distance scales: The long and short of it, V. Trimble.

  13. Modeling gap probability in discontinuous vegetation canopies

    NASA Technical Reports Server (NTRS)

    Li, Xiaowen; Strahler, Alan H.

    1987-01-01

    In the present model for the gap probability of a discontinuous vegetation canopy, the assumption of a negative exponential attenuation within individual plant canopies will yield a problem involving the distribution distances within canopies through which a ray will pass. If, however, the canopies intersect and/or overlap, so that foliage density remains constant within the overlap area, the problem can be approached with two types of approximations. Attention is presently given to the case of a comparison of modeled gap probabilities with those observed for a stand of Maryland pine, which shows good agreement for zenith angles of illumination up to about 45 deg.

  14. Closing the Pay Gap

    DTIC Science & Technology

    2000-10-01

    the pay gap has been narrowed, hut only to just under 10 percent. And current military compensation legislation does not close the gap until 2026. There...will continue to be a pay gap until 2026 unless the next administration and the next Congress provide more for pay above the 1999 legislated ramp- up...of .5 percent (one half of one percent) per year to attain pay equality . That means that soldiers, sailors, airmen, marines and Coast Guardsmen

  15. Biomechanics of Distance Running.

    ERIC Educational Resources Information Center

    Cavanagh, Peter R., Ed.

    Contributions from researchers in the field of running mechanics are included in the 13 chapters of this book. The following topics are covered: (1) "The Mechanics of Distance Running: A Historical Perspective" (Peter Cavanagh); (2) "Stride Length in Distance Running: Velocity, Body Dimensions, and Added Mass Effects" (Peter Cavanagh, Rodger…

  16. Distance Perception within Europe.

    ERIC Educational Resources Information Center

    Eysberg, Cees D.

    1985-01-01

    A distance perception survey was used to get college students enrolled in a human geography course involved and interested in the topic of perception. Students were asked to arrange 12 European capitals in sequence according to their distance from Amsterdam. Survey results are presented. (RM)

  17. A Distance Education Exemption?

    ERIC Educational Resources Information Center

    Salomon, Kenneth D.

    1999-01-01

    Discusses the U.S. Copyright Office's May 25, 1999 Report on Copyright and Digital Distance Education. Presents the Register of Copyrights' recommendations to Congress as to how to "promote distance education through networks, while maintaining an appropriate balance between the rights of copyright owners and the needs of users of copyrighted…

  18. Distance Education in Entwicklungslandern.

    ERIC Educational Resources Information Center

    German Foundation for International Development, Bonn (West Germany).

    Seminar and conference reports and working papers on distance education of adults, which reflect the experiences of many countries, are presented. Contents include the draft report of the 1979 International Seminar on Distance Education held in Addis Ababa, Ethiopia, which was jointly sponsored by the United Nations Economic Commission for Africa…

  19. Distance, Education and Inequality

    ERIC Educational Resources Information Center

    Hamnett, Chris; Butler, Tim

    2013-01-01

    In this paper we examine the role which distance, in a variety of forms, can play in the reproduction, intensification or reduction of educational inequality in different types of school systems in different countries. This is a very broad issue, and in the paper we examine the ways in which distance to school has emerged as an important factor in…

  20. Biomechanics of Distance Running.

    ERIC Educational Resources Information Center

    Cavanagh, Peter R., Ed.

    Contributions from researchers in the field of running mechanics are included in the 13 chapters of this book. The following topics are covered: (1) "The Mechanics of Distance Running: A Historical Perspective" (Peter Cavanagh); (2) "Stride Length in Distance Running: Velocity, Body Dimensions, and Added Mass Effects" (Peter Cavanagh, Rodger…

  1. "Distance Education for Newbies".

    ERIC Educational Resources Information Center

    Lennex, Lesia C.

    This paper discusses the effectiveness of distance education at Morehead State University. Distance education, which operates via fiber optic telecommunications, has been delivered to as many as 18 sites. Twenty-three faculty and 622 students have participated in this program. The technologies used to present information include full motion video…

  2. Gender and Distance Learning.

    ERIC Educational Resources Information Center

    Brunner, Cornelia

    This article examines distance learning from a gender perspective. In any new area of enterprise, expectations have an important effect on planning, implementation, and evaluation. When it comes to distance learning, a variety of images of what this exciting new technology will look like and what it can empower us to achieve will determine how we…

  3. Education at a Distance.

    ERIC Educational Resources Information Center

    Maffett, Sheryl Price

    2007-01-01

    Distance learning has been around since the old "course in a box" correspondence classes, but with the advent of sophisticated online course management systems, learning at a distance is contributing to a major paradigm shift in higher education. That shift includes applying corporate concepts to education--students, for example, are "consumers,"…

  4. Technology and Distance Education.

    ERIC Educational Resources Information Center

    Lumsden, Bruce; And Others

    The impact of the computer on education may be greater than the impact of any other technological innovation since the development of the printing press. Although distance education has relied more extensively on technological means for delivering education to its students than has traditional classroom-centered education, most distance programs…

  5. Distance Education in Entwicklungslandern.

    ERIC Educational Resources Information Center

    German Foundation for International Development, Bonn (West Germany).

    Seminar and conference reports and working papers on distance education of adults, which reflect the experiences of many countries, are presented. Contents include the draft report of the 1979 International Seminar on Distance Education held in Addis Ababa, Ethiopia, which was jointly sponsored by the United Nations Economic Commission for Africa…

  6. Estimating distances from parallaxes

    NASA Astrophysics Data System (ADS)

    Astraatmadja, Tri L.; Bailer-Jones, Coryn

    2017-01-01

    In astrometric surveys such as Gaia and LSST, parallaxes will be measured for about a billion stars, but zero distances will be measured. Distances must be inferred from the parallaxes, and the common inference practice is by inverting the parallax. This, however, is only appropriate when there is no noise present. As noise will always be present and most stars in future surveys will have non-negligible fractional parallax uncertainties, we must treat distance estimation as an inference problem. The usage of prior assumptions become unavoidable. In this talk I will present a method on how to infer distances using Bayesian inference. Three minimalists, isotropic priors are used, as well an anisotropic prior derived from the observability of stars in a Milky Way model. The performance of these priors are investigated using a simulated Gaia-like catalogue. Recent results of distance estimation using the parallaxes of 2 million Gaia DR1 stars will also be discussed.

  7. Gap Shape Classification using Landscape Indices and Multivariate Statistics

    NASA Astrophysics Data System (ADS)

    Wu, Chih-Da; Cheng, Chi-Chuan; Chang, Che-Chang; Lin, Chinsu; Chang, Kun-Cheng; Chuang, Yung-Chung

    2016-11-01

    This study proposed a novel methodology to classify the shape of gaps using landscape indices and multivariate statistics. Patch-level indices were used to collect the qualified shape and spatial configuration characteristics for canopy gaps in the Lienhuachih Experimental Forest in Taiwan in 1998 and 2002. Non-hierarchical cluster analysis was used to assess the optimal number of gap clusters and canonical discriminant analysis was used to generate the discriminant functions for canopy gap classification. The gaps for the two periods were optimally classified into three categories. In general, gap type 1 had a more complex shape, gap type 2 was more elongated and gap type 3 had the largest gaps that were more regular in shape. The results were evaluated using Wilks’ lambda as satisfactory (p < 0.001). The agreement rate of confusion matrices exceeded 96%. Differences in gap characteristics between the classified gap types that were determined using a one-way ANOVA showed a statistical significance in all patch indices (p = 0.00), except for the Euclidean nearest neighbor distance (ENN) in 2002. Taken together, these results demonstrated the feasibility and applicability of the proposed methodology to classify the shape of a gap.

  8. Gap Shape Classification using Landscape Indices and Multivariate Statistics.

    PubMed

    Wu, Chih-Da; Cheng, Chi-Chuan; Chang, Che-Chang; Lin, Chinsu; Chang, Kun-Cheng; Chuang, Yung-Chung

    2016-11-30

    This study proposed a novel methodology to classify the shape of gaps using landscape indices and multivariate statistics. Patch-level indices were used to collect the qualified shape and spatial configuration characteristics for canopy gaps in the Lienhuachih Experimental Forest in Taiwan in 1998 and 2002. Non-hierarchical cluster analysis was used to assess the optimal number of gap clusters and canonical discriminant analysis was used to generate the discriminant functions for canopy gap classification. The gaps for the two periods were optimally classified into three categories. In general, gap type 1 had a more complex shape, gap type 2 was more elongated and gap type 3 had the largest gaps that were more regular in shape. The results were evaluated using Wilks' lambda as satisfactory (p < 0.001). The agreement rate of confusion matrices exceeded 96%. Differences in gap characteristics between the classified gap types that were determined using a one-way ANOVA showed a statistical significance in all patch indices (p = 0.00), except for the Euclidean nearest neighbor distance (ENN) in 2002. Taken together, these results demonstrated the feasibility and applicability of the proposed methodology to classify the shape of a gap.

  9. Gap Shape Classification using Landscape Indices and Multivariate Statistics

    PubMed Central

    Wu, Chih-Da; Cheng, Chi-Chuan; Chang, Che-Chang; Lin, Chinsu; Chang, Kun-Cheng; Chuang, Yung-Chung

    2016-01-01

    This study proposed a novel methodology to classify the shape of gaps using landscape indices and multivariate statistics. Patch-level indices were used to collect the qualified shape and spatial configuration characteristics for canopy gaps in the Lienhuachih Experimental Forest in Taiwan in 1998 and 2002. Non-hierarchical cluster analysis was used to assess the optimal number of gap clusters and canonical discriminant analysis was used to generate the discriminant functions for canopy gap classification. The gaps for the two periods were optimally classified into three categories. In general, gap type 1 had a more complex shape, gap type 2 was more elongated and gap type 3 had the largest gaps that were more regular in shape. The results were evaluated using Wilks’ lambda as satisfactory (p < 0.001). The agreement rate of confusion matrices exceeded 96%. Differences in gap characteristics between the classified gap types that were determined using a one-way ANOVA showed a statistical significance in all patch indices (p = 0.00), except for the Euclidean nearest neighbor distance (ENN) in 2002. Taken together, these results demonstrated the feasibility and applicability of the proposed methodology to classify the shape of a gap. PMID:27901127

  10. Galactic Distance Scales

    NASA Astrophysics Data System (ADS)

    Feast, Michael W.

    This chapter begins with a discussion of the basic methods of determining astronomical distances, particularly, trigonometrical, statistical, and pulsational parallaxes. It then summarizes the current state of the calibration of various classes of pulsating variables (Classical Cepheids, type-II Cepheids, RR Lyraes, Miras, and δ Sct and SX Phe stars). Work on other distance indicators (e.g., the red giant clump and the tip of the red giant branch) is also summarized. The use of spectroscopic parallaxes and their application to supergiants and common stars as well as the methods of determining the distances to open and globular clusters are discussed. To illustrate and compare different distance indicators, their use in estimating the scale length of our Galaxy, and the distance to Galactic centre as well as the distances to the LMC, the Fornax dwarf spheroidal, and the spiral galaxy NGC4258 is discussed in some detail. An appendix summarizes some common bias problems that arise in the calibration and use of distance indicators.

  11. The Parenting Gap

    ERIC Educational Resources Information Center

    Reeves, Richard V.; Howard, Kimberly

    2013-01-01

    The parenting gap is a big factor in the opportunity gap. The chances of upward social mobility are lower for children with parents struggling to do a good job--in terms of creating a supportive and stimulating home environment. Children lucky enough to have strong parents are more likely to succeed at all the critical life stages, which means…

  12. States Address Achievement Gaps.

    ERIC Educational Resources Information Center

    Christie, Kathy

    2002-01-01

    Summarizes 2 state initiatives to address the achievement gap: North Carolina's report by the Advisory Commission on Raising Achievement and Closing Gaps, containing an 11-point strategy, and Kentucky's legislation putting in place 10 specific processes. The North Carolina report is available at www.dpi.state.nc.us.closingthegap; Kentucky's…

  13. Which Achievement Gap?

    ERIC Educational Resources Information Center

    Anderson, Sharon; Medrich, Elliott; Fowler, Donna

    2007-01-01

    From the halls of Congress to the local elementary school, conversations on education reform have tossed around the term "achievement gap" as though people all know precisely what that means. As it's commonly used, "achievement gap" refers to the differences in scores on state or national achievement tests between various…

  14. Confronting the Achievement Gap

    ERIC Educational Resources Information Center

    Gardner, David

    2007-01-01

    This article talks about the large achievement gap between children of color and their white peers. The reasons for the achievement gap are varied. First, many urban minorities come from a background of poverty. One of the detrimental effects of growing up in poverty is receiving inadequate nourishment at a time when bodies and brains are rapidly…

  15. Which Achievement Gap?

    ERIC Educational Resources Information Center

    Anderson, Sharon; Medrich, Elliott; Fowler, Donna

    2007-01-01

    From the halls of Congress to the local elementary school, conversations on education reform have tossed around the term "achievement gap" as though people all know precisely what that means. As it's commonly used, "achievement gap" refers to the differences in scores on state or national achievement tests between various…

  16. The Parenting Gap

    ERIC Educational Resources Information Center

    Reeves, Richard V.; Howard, Kimberly

    2013-01-01

    The parenting gap is a big factor in the opportunity gap. The chances of upward social mobility are lower for children with parents struggling to do a good job--in terms of creating a supportive and stimulating home environment. Children lucky enough to have strong parents are more likely to succeed at all the critical life stages, which means…

  17. Confronting the Achievement Gap

    ERIC Educational Resources Information Center

    Gardner, David

    2007-01-01

    This article talks about the large achievement gap between children of color and their white peers. The reasons for the achievement gap are varied. First, many urban minorities come from a background of poverty. One of the detrimental effects of growing up in poverty is receiving inadequate nourishment at a time when bodies and brains are rapidly…

  18. Bridging a Cultural Gap

    ERIC Educational Resources Information Center

    Leviatan, Talma

    2008-01-01

    There has been a broad wave of change in tertiary calculus courses in the past decade. However, the much-needed change in tertiary pre-calculus programmes--aimed at bridging the gap between high-school mathematics and tertiary mathematics--is happening at a far slower pace. Following a discussion on the nature of the gap and the objectives of a…

  19. The National "Expertise Gap"

    ERIC Educational Resources Information Center

    Hamilton, Kendra

    2005-01-01

    This article discusses the Woodrow Wilson National Fellowship Foundation's report, "Diversity and the Ph.D.," released in May, which documents in troubling detail the exact dimensions of what the foundation's president, Dr. Robert Weisbuch, is calling the national "expertise gap." Weisbuch states that the expertise gap extends beyond the…

  20. Senseless Extravagance, Shocking Gaps

    ERIC Educational Resources Information Center

    Weissbourd, Richard; Dodge, Trevor

    2012-01-01

    Although most people in the United States believe, at least theoretically, in educational equality, fewer and fewer appear to care about the resource gaps between affluent and poor schools, says Weissbourd. He illustrates these gaps with vivid descriptions of what he calls an "opulence arms race" among affluent independent schools, but…

  1. Senseless Extravagance, Shocking Gaps

    ERIC Educational Resources Information Center

    Weissbourd, Richard; Dodge, Trevor

    2012-01-01

    Although most people in the United States believe, at least theoretically, in educational equality, fewer and fewer appear to care about the resource gaps between affluent and poor schools, says Weissbourd. He illustrates these gaps with vivid descriptions of what he calls an "opulence arms race" among affluent independent schools, but…

  2. Information Gap Activities.

    ERIC Educational Resources Information Center

    Cicekdag, Mehmet Ali

    1995-01-01

    Focuses on a real world technique used to teach language proficiency in the classroom. This method involves creating deliberate information and opinion gaps by administering pop quizzes and other communicative games and filling those gaps through cooperative action. Use of this technique generated heated discussion among students. (nine…

  3. The National "Expertise Gap"

    ERIC Educational Resources Information Center

    Hamilton, Kendra

    2005-01-01

    This article discusses the Woodrow Wilson National Fellowship Foundation's report, "Diversity and the Ph.D.," released in May, which documents in troubling detail the exact dimensions of what the foundation's president, Dr. Robert Weisbuch, is calling the national "expertise gap." Weisbuch states that the expertise gap extends beyond the…

  4. Narrowing Participation Gaps

    ERIC Educational Resources Information Center

    Hand, Victoria; Kirtley, Karmen; Matassa, Michael

    2015-01-01

    Shrinking the achievement gap in mathematics is a tall order. One way to approach this challenge is to think about how the achievement gap manifests itself in the classroom and take concrete action. For example, opportunities to participate in activities that involve mathematical reasoning and argumentation in a safe and supportive manner are…

  5. Updated Starshade Technology Gap List

    NASA Astrophysics Data System (ADS)

    Crill, Brendan P.; Siegler, Nicholas

    2017-01-01

    NASA's Exoplanet Exploration Program (ExEP) guides the development of technology that enables the direct imaging and characterization of exo-Earths in the habitable zone of their stars, for future space observatories. Here we present the Starshade portion of the 2017 ExEP Enabling Technology Gap List, an annual update to ExEP's list of of technology to be advanced in the next 1-5 years. A Starshade is an external occulter on an independent spacecraft, allowing a space telescope to achieve exo-Earth imaging contrast requirements by blocking starlight before it enters the telescope. Building and operating a Starshade requires new technology: the occulter is a structure tens of meters in diameter that must be positioned precisely at a distance of tens of thousands of kilometers from the telescope. We review the current state-of-the-art performance and the performance level that must be achieved for a Starshade.

  6. Optimized measurement of gaps

    NASA Astrophysics Data System (ADS)

    Harding, Kevin; Ramamurthy, Rajesh

    2017-05-01

    Gaps are important in a wide range of measurements in manufacturing, from the fitting of critical assemblies too cosmetic features on cars. There are a variety of potential sensors that can measure a gap opening, each with aspects of gap measurements that they do well and other aspects where the technology may lack capability. This paper provides a review of a wide range of optical gages from structured light to passive systems and from line to area measurement. Each technology is considered relative to the ability to accurately measure a gap, including issues of edge effects, edge shape, surface finish, and transparency. Finally, an approach will be presented for creating an optimize measurement off gap openings for critical assembly applications.

  7. Measuring the Flow Through the Kerama Gap

    DTIC Science & Technology

    2012-09-30

    Jae-Hun Park Graduate School of Oceanography University of Rhode Island Narragansett, RI 02882-1197 Phone: 401-874-6515 & 401-874-6610 Fax...The principal flows in and out of the East China Sea (ECS) are through channels penetrating the Ryukyu Ridge (Figure 1). Since ~20 Sv of Kuroshio...Figure 1. The Ryukyu ridgeline, from Taiwan (on the left) to Kyushu, Japan (on the right). The Kerama Gap at Distance = 600 km from

  8. Review of Distance Education Research (2000 to 2008): Analysis of Research Areas, Methods, and Authorship Patterns

    ERIC Educational Resources Information Center

    Zawacki-Richter, Olaf; Backer, Eva Maria; Vogt, Sebastian

    2009-01-01

    This paper presents a review of distance education literature to describe the status thereof and to identify gaps and priority areas in distance education research based on a validated classification of research areas. The articles (N = 695) published in five prominent distance education journals between 2000 and 2008 were reviewed for this study.…

  9. Geodetic distance measuring apparatus

    NASA Astrophysics Data System (ADS)

    Abshire, J. B.

    1980-12-01

    A geodetic distance measuring apparatus which compensates for the refractive index of the atmosphere is discussed. A mode locked laser system with a laser device and its peripheral components is utilized to derive two mutually phase locked optical wavelength signals and one phase locked microwave CW signal which respectively traverse the same distance measurement path. The optical signals are comprised of pulse type signals. Phase comparison of the two optical wavelength pulse signals is used to provide the dry air density while phase comparison of one of the optical wavelength pulse signals and the microwave CW signal issued to provide wet or water vapor density of the air. The distance to be measured corrected for the atmospheric dry air and water vapor densities in the measurement path is computed from these measurements. A time interval unit is included for measuring transit time of individual optical pulses for resolving the phase ambiguity needed with the phase measurements to give the true target distance.

  10. Technology and Distance Education.

    ERIC Educational Resources Information Center

    Pelton, J. N.; Bates, A. W.

    1991-01-01

    Two articles evaluate the impact of new transmission and information technologies on education: "Technology and Education--Friend or Foe?" (Pelton) and "Third Generation Distance Education: The Challenge of New Technology" (Bates). (SK)

  11. Learning Pullback HMM Distances.

    PubMed

    Cuzzolin, Fabio; Sapienza, Michael

    2014-07-01

    Recent work in action recognition has exposed the limitations of methods which directly classify local features extracted from spatio-temporal video volumes. In opposition, encoding the actions' dynamics via generative dynamical models has a number of attractive features: however, using all-purpose distances for their classification does not necessarily deliver good results. We propose a general framework for learning distance functions for generative dynamical models, given a training set of labelled videos. The optimal distance function is selected among a family of pullback ones, induced by a parametrised automorphism of the space of models. We focus here on hidden Markov models and their model space, and design an appropriate automorphism there. Experimental results are presented which show how pullback learning greatly improves action recognition performances with respect to base distances.

  12. Distance to Dark Bodies

    NASA Image and Video Library

    2007-05-30

    Using the unique orbit of NASA Spitzer Space Telescope and a depth-perceiving trick called parallax, astronomers have determined the distance to an invisible Milky Way object called OGLE-2005-SMC-001.

  13. Distance learning perspectives.

    PubMed

    Pandza, Haris; Masic, Izet

    2013-01-01

    The development of modern technology and the Internet has enabled the explosive growth of distance learning. distance learning is a process that is increasingly present in the world. This is the field of education focused on educating students who are not physically present in the traditional classrooms or student's campus. described as a process where the source of information is separated from the students in space and time. If there are situations that require the physical presence of students, such as when a student is required to physically attend the exam, this is called a hybrid form of distance learning. This technology is increasingly used worldwide. The Internet has become the main communication channel for the development of distance learning.

  14. Automobile Stopping Distances.

    ERIC Educational Resources Information Center

    Logue, L. J.

    1979-01-01

    Discusses the effect of vehicle mass on stopping distances. Analyzes an example of a sample vehicle and tire, and calculates the braking acceleration showing the effect of different factors on the stopping performance of the tires. (GA)

  15. Automobile Stopping Distances.

    ERIC Educational Resources Information Center

    Logue, L. J.

    1979-01-01

    Discusses the effect of vehicle mass on stopping distances. Analyzes an example of a sample vehicle and tire, and calculates the braking acceleration showing the effect of different factors on the stopping performance of the tires. (GA)

  16. Large gap control in electromagnetic levitation.

    PubMed

    Banerjee, Subrata; Prasad, Dinkar; Pal, Jayanta

    2006-04-01

    This paper describes design and implementation of a single axis dc attraction type electromagnetic suspension system where an electromagnet of 2.6 kg mass is levitated over a large gap under a fixed ferromagnetic guide-way. The electromagnet exhibits nonlinear force-current-distance characteristics, and if controllers are to be designed by using linear analysis, the air-gap is restricted to a small region around the chosen nominal operating point. In this work, an attempt has been made to increase the operating range of an electromagnetic suspension system by using the concept of piecewise linear control where the nonlinear force-current-airgap relationships of the magnetic suspension system have been successively linearized at several operating points with a suitable controller designed for each operating point. A novel analog switching scheme has been designed and implemented to automatically switch to the relevant controller depending on the actual air-gap.

  17. An ERP Study of Causative Cleft Construction in Japanese: Evidence for the Preference of Shorter Linear Distance in Sentence Comprehension.

    PubMed

    Yano, Masataka; Sakamoto, Tsutomu

    2016-04-01

    This study examined the processing of two types of Japanese causative cleft constructions (subject-gap vs. object-gap) by conducting an event-related brain potential experiment to clarify the processing mechanism of long-distance dependencies. The results demonstrated that the subject-gap constructions elicited larger P600 effects than the object-gap constructions. Based on these findings, we argue that the linear distance rather than the structural distance between the extracted argument (filler) and its original gap position is a crucial factor for determining processing costs of gap-filler dependency in Japanese causative cleft constructions. This argument indicates that (at least) some types of long-distance dependencies are sensitive to linear distance.

  18. Bridging The Inferential Gap

    PubMed Central

    Stewart, Walter F.; Shah, Nirav R.; Selna, Mark J.; Paulus, Ronald A.; Walker, James M.

    2009-01-01

    Most clinical decisions involve bridging the inferential gap: Clinicians are required to “fill in” where they lack knowledge or where no knowledge yet exists. In this context we consider how the inferential gap is a product, in part, of how knowledge is created, the limits to gaining access to such knowledge, and the variable ways in which knowledge is translated into decisions. We consider how electronic health records (EHRs) will help narrow this gap by accelerating the creation of evidence relevant to everyday practice needs and facilitating real-time use of knowledge in practice. PMID:17259202

  19. SPARK GAP SWITCH

    DOEpatents

    Neal, R.B.

    1957-12-17

    An improved triggered spark gap switch is described, capable of precisely controllable firing time while switching very large amounts of power. The invention in general comprises three electrodes adjustably spaced and adapted to have a large potential impressed between the outer electrodes. The central electrode includes two separate elements electrically connected togetaer and spaced apart to define a pair of spark gaps between the end electrodes. Means are provided to cause the gas flow in the switch to pass towards the central electrode, through a passage in each separate element, and out an exit disposed between the two separate central electrode elements in order to withdraw ions from the spark gap.

  20. Presence at a distance.

    PubMed

    Haddouk, Lise

    2015-01-01

    Nowadays in the context of the cyberculture, computer-mediated inter-subjective relationships are part of our everyday lives, in both the professional and personal spheres, and for all age groups. In the clinical field, many applications have been developed to facilitate the exchange of informations and mediate the relationship between patient and therapist. In psychology, more or less immersive technologies are used, to encourage the feeling of presence among the users, and to trigger certain psychological processes. In our research, we have explored the remote clinical interview through videoconferencing, with the development and utilisation of the iPSY platform, totally focused on this objective. In this context, we have considered the notion of intersubjectivity, despite the physical absence. This research is leading us today to envision the notions of distance and presence, and possibly to redefine them. Thus, can we still oppose physical distance to psychological distance? Can we still affirm that the physical absence does not permit a psychological co-presence in certain interactions, like this observed in video interviews? The results show that the psychological processes, activated in this context, are similar to those observed in "traditional" clinical consults between the patient and the therapist. However, certain specifics have led us to consider the concept of distance, here influenced by the framework, and to observe its effects. This distance could possibly constitute a therapeutic lever for some patients, notably for those who have difficulties establishing the right psychological distance in their relationships with others. According to these results, can "distance" still be opposed to "presence", or could it be re-defined? This also opens up questions on the more general concept of digital relationships, and the definition of their specificities.

  1. Drafting distance in swimming.

    PubMed

    Chatard, Jean-Claude; Wilson, Barry

    2003-07-01

    This study investigates the effect of the distance separating the lead and draft swimmers on the metabolic and hydrodynamic responses of the draft swimmer. A nondrafting swim of 4 min at 95% of the best 1500-m pace for 11 swimmers was compared with swimming in a drafting position at four different distances directly behind another swimmer (0, 50, 100, and 150 cm). Swimming performance was assessed by stroke rate and stroke length; the metabolic response by oxygen uptake, heart rate, and blood lactate; and the rating of perceived exertion by the Borg scale. Passive drag was assessed at these drafting distances by passive towing. Then, passive drag was measured in six swimmers towed in six lateral drafting positions, with swimmers separated by approximately 40 cm, and then measured in two positions at the rear of the lead swimmer with a reduced lateral distance between swimmers of 50 and 0 cm. Oxygen uptake, heart rate, blood lactate, rating of perceived exertion, and stroke rate were significantly reduced and stroke length was significantly increased in all drafting positions compared with the nondrafting position. For drag, the most advantageous drafting distances were 0 and 50 cm back from the toes of the lead swimmer. Drag was reduced by 21% and 20%, respectively. In lateral drafting, drag was significantly reduced by 6% and 7%, respectively, at 50 and 100 cm back from the hands of the lead swimmer. Swimming behind another swimmer at a distance between 0 and 50 cm back from the toes was the most advantageous, whereas in lateral drafting the optimal distance was 50-100 cm back from the hands of the lead swimmer.

  2. Distance Education: A Cost Analysis.

    ERIC Educational Resources Information Center

    Jones, Judy I.; And Others

    This report provides administrators, school boards, and policymakers with data to help them in the decision making process related to distance education systems. A literature review covers theories of distance education, distance education today, the economics of distance education, distance education and technology, transmission systems, and…

  3. Long distance entanglement distribution

    NASA Astrophysics Data System (ADS)

    Broadfoot, Stuart Graham

    Developments in the interdisciplinary field of quantum information open up previously impossible abilities in the realms of information processing and communication. Quantum entanglement has emerged as one property of quantum systems that acts as a resource for quantum information processing and, in particular, enables teleportation and secure cryptography. Therefore, the creation of entangled resources is of key importance for the application of these technologies. Despite a great deal of research the efficient creation of entanglement over long distances is limited by inevitable noise. This problem can be overcome by creating entanglement between nodes in a network and then performing operations to distribute the entanglement over a long distance. This thesis contributes to the field of entanglement distribution within such quantum networks. Entanglement distribution has been extensively studied for one-dimensional networks resulting in "quantum repeater" protocols. However, little work has been done on higher dimensional networks. In these networks a fundamentally different scaling, called "long distance entanglement distribution", can appear between the resources and the distance separating the systems to be entangled. I reveal protocols that enable long distance entanglement distribution for quantum networks composed of mixed state and give a few limitations to the capabilities of entanglement distribution. To aid in the implementation of all entanglement distribution protocols I finish by introducing a new system, composed of an optical nanofibre coupled to a carbon nanotube, that may enable new forms of photo-detectors and quantum memories.

  4. The Cepheid distance scale

    NASA Technical Reports Server (NTRS)

    Madore, Barry F.; Freedman, Wendy L.

    1991-01-01

    Developments concerning the period-luminosity (PL) relation for classical Cepheids are discussed with particular emphasis on the fact that Cepheids continue to provide the most homogeneous and reliable set of distances to many nearby galaxies. Observational programs relating to extragalactic Cepheids are also reviewed, and new distances and reddenings to individual galaxies are determined from these data using multiwavelength PL relations, based for the first time on self-consistent calibrating data sets. Three recent promising secondary extragalactic distance indicators (Tully-Fisher, planetary nebula luminosity functions, and surface-brightness fluctuations) tie their zero points to the Cepheid distance scale and give globally consistent values for the Hubble constant of about 80 km/sec/Mpc. Tying the Faber-Jackson relation and the supernova distance scales to the Leo and Virgo clusters yields similar results. Such a value for the Hubble constant is marginally inconsistent with new estimates of the ages of globular clusters, and it may prove to be a serious problem for standard cold-dark-matter models of the universe.

  5. Optimal flight initiation distance.

    PubMed

    Cooper, William E; Frederick, William G

    2007-01-07

    Decisions regarding flight initiation distance have received scant theoretical attention. A graphical model by Ydenberg and Dill (1986. The economics of fleeing from predators. Adv. Stud. Behav. 16, 229-249) that has guided research for the past 20 years specifies when escape begins. In the model, a prey detects a predator, monitors its approach until costs of escape and of remaining are equal, and then flees. The distance between predator and prey when escape is initiated (approach distance = flight initiation distance) occurs where decreasing cost of remaining and increasing cost of fleeing intersect. We argue that prey fleeing as predicted cannot maximize fitness because the best prey can do is break even during an encounter. We develop two optimality models, one applying when all expected future contribution to fitness (residual reproductive value) is lost if the prey dies, the other when any fitness gained (increase in expected RRV) during the encounter is retained after death. Both models predict optimal flight initiation distance from initial expected fitness, benefits obtainable during encounters, costs of escaping, and probability of being killed. Predictions match extensively verified predictions of Ydenberg and Dill's (1986) model. Our main conclusion is that optimality models are preferable to break-even models because they permit fitness maximization, offer many new testable predictions, and allow assessment of prey decisions in many naturally occurring situations through modification of benefit, escape cost, and risk functions.

  6. Fiber optic gap gauge

    DOEpatents

    Wood, Billy E.; Groves, Scott E.; Larsen, Greg J.; Sanchez, Roberto J.

    2006-11-14

    A lightweight, small size, high sensitivity gauge for indirectly measuring displacement or absolute gap width by measuring axial strain in an orthogonal direction to the displacement/gap width. The gap gauge includes a preferably titanium base having a central tension bar with springs connecting opposite ends of the tension bar to a pair of end connector bars, and an elongated bow spring connected to the end connector bars with a middle section bowed away from the base to define a gap. The bow spring is capable of producing an axial strain in the base proportional to a displacement of the middle section in a direction orthogonal to the base. And a strain sensor, such as a Fabry-Perot interferometer strain sensor, is connected to measure the axial strain in the base, so that the displacement of the middle section may be indirectly determined from the measurement of the axial strain in the base.

  7. Gap filler material

    NASA Image and Video Library

    2005-08-04

    S114-E-6674 (4 August 2005) --- On Discovery's middeck, one of the STS-114 crew members holds a piece of the gap filler material that had been protruding from between TPS tiles and retrieved the day before by Mission Specialist Stephen K. Robinson, during the third spacewalk of the flight. Robinson used his gloved fingers to pull out this gap filler and another one from Discovery's belly while carefully supported and maneuvered by the Canadian-built remote manipulator system, operated inside Discovery's cabin by astronauts Wendy B. Lawrence and James M. Kelly. Gap fillers like those Robinson removed are thin, coated Nextel fabric. The protruding gap fillers were identified in photos taken by Station crewmembers using telephoto lenses as Discovery did a slow back flip about 600 feet below before docking.

  8. Gaps in Oncology

    Cancer.gov

    The first plenary of the EPEC-O (Education in Palliative and End-of-Life Care for Oncology) Self-Study Original Version provides background for the curriculum and identifies gaps in current and desired comprehensive cancer care.

  9. Theoretical Principles of Distance Education.

    ERIC Educational Resources Information Center

    Keegan, Desmond, Ed.

    This book contains the following papers examining the didactic, academic, analytic, philosophical, and technological underpinnings of distance education: "Introduction"; "Quality and Access in Distance Education: Theoretical Considerations" (D. Randy Garrison); "Theory of Transactional Distance" (Michael G. Moore);…

  10. Distance estimation in vista space.

    PubMed

    Daum, S Oliver; Hecht, Heiko

    2009-07-01

    Although distance estimation has been extensively studied in the laboratory, our ability to judge large distances in the field is not well researched. We challenge the notion that large distances are uniformly underestimated. We presented different targets to observers at distances ranging from 25 to 500 m to obtain egocentric distance judgments in natural environments. Three experiments showed that observers tend to underestimate distances below 75 m in a large open field, whereas they overestimate farther distances. Both the eye height of the observer and the size of the target also influenced distance estimation. We conclude that the notion of a uniform vista space has to be reconceived.

  11. Technology & Distance Learning Survey.

    ERIC Educational Resources Information Center

    Florida Human Resources Development, Inc., Gainesville.

    A survey was conducted to assess the current state of technology and distance learning awareness and usage in Florida's adult education and community-based programs. Data were gathered through a survey of 350 adult practitioners, literacy providers, community-based organizations and libraries throughout the state (125 responses [36 percent return…

  12. Going the Distance

    ERIC Educational Resources Information Center

    Barack, Lauren

    2005-01-01

    Sixty years ago, distance education probably involved a pen, paper, and secretarial classes conducted via snail mail. Today, students in ever-increasing numbers are more likely to link to the Internet to learn how to conjugate French verbs or dissect frogs in Advanced Placement courses, according to a new landmark study from the U. S. Department…

  13. Distance Learning Case Studies.

    ERIC Educational Resources Information Center

    Barker, Bruce O.

    The Office of Technology Assessment authorized a series of case studies in 1989 to investigate how technologies, services, and programs are implemented in distance education projects. The studies were also intended to look at the role of local, state, and federal agencies, and other public and private entities in providing educational services to…

  14. Misconceptions of Astronomical Distances

    ERIC Educational Resources Information Center

    Miller, Brian W.; Brewer, William F.

    2010-01-01

    Previous empirical studies using multiple-choice procedures have suggested that there are misconceptions about the scale of astronomical distances. The present study provides a quantitative estimate of the nature of this misconception among US university students by asking them, in an open-ended response format, to make estimates of the distances…

  15. Advances in Distance Learning.

    ERIC Educational Resources Information Center

    1999

    This document contains three symposium papers on advances in distance learning. "The Adoption of Computer Technology and Telecommunications: A Case Study" (Larry M. Dooley, Teri Metcalf, Ann Martinez) reports on a study of the possible applications of two theoretical models (Rogers' Diffusion of Innovations model and the Concerns-Based…

  16. Learning across Distance

    ERIC Educational Resources Information Center

    Cowan, Kristina

    2009-01-01

    A 2008 report, "Keeping Pace with K-12 Online Learning," commissioned by North American Council for Online Learning (NACOL) and others, defines online learning as "teacher-led education that takes place over the Internet, with the teacher and student separated geographically." The term "distance learning" includes online education, but is…

  17. Focus on Distance Education.

    ERIC Educational Resources Information Center

    Grenzky, Janet; Maitland, Christine

    2001-01-01

    As a followup to a survey of distance education faculty, the National Education Association conducted two 3-hour focus groups with 12 higher education faculty members in June 2000. The purpose of the groups was to gain more understanding of the complexity of feelings and opinions expressed in a telephone survey conducted in March 2000. The…

  18. Accreditation of Distance Learning

    ERIC Educational Resources Information Center

    Demirel, Ergün

    2016-01-01

    The higher education institutes aspire to gain reputation of quality having accreditation from internationally recognized awarding bodies. The accreditation leads and provides quality assurance for education. Although distance learning becomes a significant part of the education system in the 21st century, there is still a common opinion that the…

  19. On Defining Distance Education.

    ERIC Educational Resources Information Center

    Rumble, Greville

    1989-01-01

    Reviews past definitions of distance education and offers a new five-part definition of the concept. Topics discussed include the roles of the teachers and students; physical separation of teachers and learners; the influence of an educational organization; communication between teachers and students; and the use of technical media. (22…

  20. Rapport in Distance Education

    ERIC Educational Resources Information Center

    Murphy, Elizabeth; Rodriguez-Manzanares, Maria A.

    2012-01-01

    Rapport has been recognized as important in learning in general but little is known about its importance in distance education (DE). The study we report on in this paper provides insights into the importance of rapport in DE as well as challenges to and indicators of rapport-building in DE. The study relied on interviews with 42 Canadian…

  1. Long-Distance Learning.

    ERIC Educational Resources Information Center

    Charron, Elisabeth; Obbink, Kim

    1993-01-01

    Discusses the following questions in choosing distance education courses: Will I be able to "talk" with the instructor? Will I be able to talk with other course participants? Does the course include laboratories or other hands-on experiences? What equipment will I need to participate? What technical assistance will be available? Who is the course…

  2. Long Distance Learning.

    ERIC Educational Resources Information Center

    Villeneuve, Phyllis, Ed.

    1997-01-01

    This report, from the Faculty Association of Community and Technical Colleges (FACTC) in Washington, focuses on various distance learning courses offered by the state's two-year colleges. The report contains 16 articles from faculty members and students, including: (1) "The Emperor's New Tutor: A Confession" (Sydney Wallace Stegall); (2)…

  3. Encyclopedia of Distance Learning

    ERIC Educational Resources Information Center

    Howard, Caroline, Ed.; Boettecher, Judith, Ed.; Justice, Lorraine, Ed.; Schenk, Karen, Ed.; Rogers, Patricia, Ed.; Berg, Gary, Ed.

    2005-01-01

    The innovations in computer and communications technologies combined with on-going needs to deliver educational programs to students regardless of their physical locations, have lead to the innovation of distance education programs and technologies. To keep up with recent developments in both areas of technologies and techniques related to…

  4. Misconceptions of Astronomical Distances

    ERIC Educational Resources Information Center

    Miller, Brian W.; Brewer, William F.

    2010-01-01

    Previous empirical studies using multiple-choice procedures have suggested that there are misconceptions about the scale of astronomical distances. The present study provides a quantitative estimate of the nature of this misconception among US university students by asking them, in an open-ended response format, to make estimates of the distances…

  5. Distance Learning's Growing Reach.

    ERIC Educational Resources Information Center

    Walsh, John; Reese, Bob

    1995-01-01

    Examines the use of videoconferencing and video broadcasts for distance learning and presents examples: the Georgia Statewide Academic and Medical System, California State University System, Kansas City Education Network, Impact North Carolina, the School of Visual Arts in Manhattan, National Technological University, GALAXY Classroom, and…

  6. Going the Distance

    ERIC Educational Resources Information Center

    Barack, Lauren

    2005-01-01

    Sixty years ago, distance education probably involved a pen, paper, and secretarial classes conducted via snail mail. Today, students in ever-increasing numbers are more likely to link to the Internet to learn how to conjugate French verbs or dissect frogs in Advanced Placement courses, according to a new landmark study from the U. S. Department…

  7. ESP and Distance Learning.

    ERIC Educational Resources Information Center

    Boyle, Ron

    1994-01-01

    Distance learning (DL) is proposed as one means of providing in-session language classes for non-native-speaking postgraduate students at English-medium universities. A DL preparatory language program at the Asian Institute of Technology in Bangkok is described. (48 references) (Author/LB)

  8. Learning across Distance

    ERIC Educational Resources Information Center

    Cowan, Kristina

    2009-01-01

    A 2008 report, "Keeping Pace with K-12 Online Learning," commissioned by North American Council for Online Learning (NACOL) and others, defines online learning as "teacher-led education that takes place over the Internet, with the teacher and student separated geographically." The term "distance learning" includes online education, but is…

  9. Peterson's Distance Learning 1997.

    ERIC Educational Resources Information Center

    Peterson's Guides, Inc., Princeton, NJ.

    This guide provides profiles of distance learning programs in postsecondary education institutions throughout the United States, alphabetically by institution. The descriptions contain information on program access, media used (e.g., videocassette, correspondence, television, radio, teleconferencing), student services offered, application process,…

  10. Prospect of Distance Learning

    ERIC Educational Resources Information Center

    Rahman, Monsurur; Karim, Reza; Byramjee, Framarz

    2015-01-01

    Many educational institutions in the United States are currently offering programs through distance learning, and that trend is rising. In almost all spheres of education a developing country like Bangladesh needs to make available the expertise of the most qualified faculty to her distant people. But the fundamental question remains as to whether…

  11. Determining average yarding distance.

    Treesearch

    Roger H. Twito; Charles N. Mann

    1979-01-01

    Emphasis on environmental and esthetic quality in timber harvesting has brought about increased use of complex boundaries of cutting units and a consequent need for a rapid and accurate method of determining the average yarding distance and area of these units. These values, needed for evaluation of road and landing locations in planning timber harvests, are easily and...

  12. Effect of Geographic Distance on Distance Education: An Empirical Study

    ERIC Educational Resources Information Center

    Luo, Heng; Robinson, Anthony C.; Detwiler, Jim

    2014-01-01

    This study investigates the effect of geographic distance on students' distance learning experience with the aim to provide tentative answers to a fundamental question--does geographic distance matter in distance education? Using educational outcome data collected from an online master's program in Geographic Information Systems, this study…

  13. Celebrating Distance Teaching Innovations: The Certificate in Distance Teaching.

    ERIC Educational Resources Information Center

    Boylan, Colin; Tuovinen, Juhani

    Charles Sturt University (Riverina, Australia) has initiated the Certificate in Distance Teaching course for rural teachers working in a distance education setting to extend their understandings about rural and distance education topics. Two semester-long subjects constitute the course: pedagogy of distance teaching and organization of distance…

  14. Distance Training as Part of a Distance Consulting Solution.

    ERIC Educational Resources Information Center

    Fulantelli, Giovanni; Chiazzese, Giuseppe; Allegra, Mario

    "Distance Training" models, when integrated in a more complex framework, such as a "Distance Consulting" model, present specific features and impose a revision of the strategies commonly adopted in distance training experiences. This paper reports on the distance training strategies adopted in a European funded project aimed at…

  15. Acoustic cues underlying auditory distance in barn owls.

    PubMed

    Kim, Duck O; Moiseff, Andrew; Turner, J Bradley; Gull, Justin

    2008-04-01

    We conclude that: (1) among several cues examined, the monaural cue of direct-to-reverberant (D/R) ratio in the ipsilateral ear provides the most information about sound-source distance; (2) interaural level difference (ILD) provides less information about sound-source distance; and (3) a comprehensive theory of three-dimensional auditory localization must incorporate the fact that all of the major acoustic cues change with distance. Neural mechanisms underlying auditory localization of distance are poorly understood. The present study was an initial step toward filling this gap in knowledge. The binaural room impulse responses of adult barn owls were measured. The sound source was placed at various distances (up to 80 cm) and azimuths (0-90 degrees) relative to the owl's head, with the elevation kept at 0 degrees . We determined the value of each cue for a 3-10 kHz band, and found that: (1) D/R ratio of signal amplitudes provided the most information about sound-source distance; (2) the ipsilateral D/R ratio represented distance more clearly than the contralateral or binaural-average D/R ratios; (3) ILD of direct signals increased with decreasing distance under certain conditions; (3) interaural time difference (ITD) of direct signals increased with decreasing distance at 90 degrees azimuth; and (4) the spectral patterns of ILD and the monaural direct signals changed with distance in complex ways.

  16. Precision gap particle separator

    DOEpatents

    Benett, William J.; Miles, Robin; Jones, II., Leslie M.; Stockton, Cheryl

    2004-06-08

    A system for separating particles entrained in a fluid includes a base with a first channel and a second channel. A precision gap connects the first channel and the second channel. The precision gap is of a size that allows small particles to pass from the first channel into the second channel and prevents large particles from the first channel into the second channel. A cover is positioned over the base unit, the first channel, the precision gap, and the second channel. An port directs the fluid containing the entrained particles into the first channel. An output port directs the large particles out of the first channel. A port connected to the second channel directs the small particles out of the second channel.

  17. MULTIPLE SPARK GAP SWITCH

    DOEpatents

    Schofield, A.E.

    1958-07-22

    A multiple spark gap switch of unique construction is described which will permit controlled, simultaneous discharge of several capacitors into a load. The switch construction includes a disc electrode with a plurality of protuberances of generally convex shape on one surface. A firing electrode is insulatingly supponted In each of the electrode protuberances and extends substantially to the apex thereof. Individual electrodes are disposed on an insulating plate parallel with the disc electrode to form a number of spark gaps with the protuberances. These electrodes are each connected to a separate charged capacitor and when a voltage ls applied simultaneously between the trigger electrodes and the dlsc electrode, each spark gap fires to connect its capacitor to the disc electrode and a subsequent load.

  18. Regeneration in bottomland forest canopy gaps six years after variable retention harvests to enhance wildlife habitat

    USGS Publications Warehouse

    Twedt, Daniel J.; Somershoe, Scott G.; Guldin, James M.

    2013-01-01

    To promote desired forest conditions that enhance wildlife habitat in bottomland forests, managers prescribed and implemented variable-retention harvest, a.k.a. wildlife forestry, in four stands on Tensas River National Wildlife Refuge, LA. These treatments created canopy openings (gaps) within which managers sought to regenerate shade-intolerant trees. Six years after prescribed harvests, we assessed regeneration in 41 canopy gaps and 4 large (>0.5-ha) patch cut openings that resulted from treatments and in 21 natural canopy gaps on 2 unharvested control stands. Mean gap area of anthropogenic gaps (582 m²) was greater than that of natural gaps (262 m²). Sweetgum (Liquidambar styraciflua) and red oaks (Quercus nigra, Q. nuttallii, and Q. phellos) were common in anthropogenic gaps, whereas elms (Ulmus spp.) and sugarberry (Celtis laevigata) were numerous in natural gaps. We recommend harvest prescriptions include gaps with diameter >25 m, because the proportion of shade-intolerant regeneration increased with gap area up to 500 m². The proportion of shade-intolerant definitive gap fillers (individuals likely to occupy the canopy) increased with gap area: 35 percent in natural gaps, 54 percent in anthropogenic gaps, and 84 percent in patch cuts. Sweetgum, green ash (Fraxinus pennsylvanica), and red oaks were common definitive gap fillers.

  19. Quality Assurance in Distance Education: The Challenges to Be Addressed

    ERIC Educational Resources Information Center

    Stella, Antony; Gnanam, A.

    2004-01-01

    Integration of technology in all forms of education has narrowed down the gap between the on- and off-campus students and has resulted in the use of the more broad-based term "distributed learning". Consequently, distance learning is seen as a subset of distributed learning, focusing on students who may be separated in time and space from their…

  20. The Role of Dialogue in Distance Education: A Qualitative Study

    ERIC Educational Resources Information Center

    Watts, Lynette K.

    2010-01-01

    Distance education has come a long way from its first offerings of pen and paper when submissions had to be mailed and no interaction occurred between students and instructors. One concern that has remained is that of keeping students connected to peers and instructors. Moore (1973) stated this psychological and communication gap (transactional…

  1. Teaching Languages from a Distance through Multipoint Videoconferencing

    ERIC Educational Resources Information Center

    Acar, Ahmet

    2007-01-01

    The most commonly used and discussed videoconferencing mode for teaching languages from a distance is two-way simultaneous, or point-to-point, videoconferencing. Applications of multipoint videoconferencing to language classes, however, are not very common. This article aims to fill that gap by presenting the technical and pedagogical dimensions…

  2. Quality Assurance in Distance Education: The Challenges to Be Addressed

    ERIC Educational Resources Information Center

    Stella, Antony; Gnanam, A.

    2004-01-01

    Integration of technology in all forms of education has narrowed down the gap between the on- and off-campus students and has resulted in the use of the more broad-based term "distributed learning". Consequently, distance learning is seen as a subset of distributed learning, focusing on students who may be separated in time and space from their…

  3. Mass gap without confinement

    NASA Astrophysics Data System (ADS)

    Faedo, Antón F.; Mateos, David; Pravos, David; Subils, Javier G.

    2017-06-01

    We revisit a one-parameter family of three-dimensional gauge theories with known supergravity duals. We show that three infrared behaviors are possible. For generic values of the parameter, the theories exhibit a mass gap but no confinement, meaning no linear quark-antiquark potential; for one limiting value of the parameter the theory flows to an infrared fixed point; and for another limiting value it exhibits both a mass gap and confinement. Theories close to these limiting values exhibit quasi-conformal and quasi-confining dynamics, respectively. Eleven-dimensional supergravity provides a simple, geometric explanation of these features.

  4. An ERP Study of Causative Cleft Construction in Japanese: Evidence for the Preference of Shorter Linear Distance in Sentence Comprehension

    ERIC Educational Resources Information Center

    Yano, Masataka; Sakamoto, Tsutomu

    2016-01-01

    This study examined the processing of two types of Japanese causative cleft constructions (subject-gap vs. object-gap) by conducting an event-related brain potential experiment to clarify the processing mechanism of long-distance dependencies. The results demonstrated that the subject-gap constructions elicited larger P600 effects than the…

  5. An ERP Study of Causative Cleft Construction in Japanese: Evidence for the Preference of Shorter Linear Distance in Sentence Comprehension

    ERIC Educational Resources Information Center

    Yano, Masataka; Sakamoto, Tsutomu

    2016-01-01

    This study examined the processing of two types of Japanese causative cleft constructions (subject-gap vs. object-gap) by conducting an event-related brain potential experiment to clarify the processing mechanism of long-distance dependencies. The results demonstrated that the subject-gap constructions elicited larger P600 effects than the…

  6. Distance between images

    NASA Technical Reports Server (NTRS)

    Gualtieri, J. A.; Le Moigne, J.; Packer, C. V.

    1992-01-01

    Comparing two binary images and assigning a quantitative measure to this comparison finds its purpose in such tasks as image recognition, image compression, and image browsing. This quantitative measurement may be computed by utilizing the Hausdorff distance of the images represented as two-dimensional point sets. In this paper, we review two algorithms that have been proposed to compute this distance, and we present a parallel implementation of one of them on the MasPar parallel processor. We study their complexity and the results obtained by these algorithms for two different types of images: a set of displaced pairs of images of Gaussian densities, and a comparison of a Canny edge image with several edge images from a hierarchical region growing code.

  7. The sound of distance.

    PubMed

    Rabaglia, Cristina D; Maglio, Sam J; Krehm, Madelaine; Seok, Jin H; Trope, Yaacov

    2016-07-01

    Human languages may be more than completely arbitrary symbolic systems. A growing literature supports sound symbolism, or the existence of consistent, intuitive relationships between speech sounds and specific concepts. Prior work establishes that these sound-to-meaning mappings can shape language-related judgments and decisions, but do their effects generalize beyond merely the linguistic and truly color how we navigate our environment? We examine this possibility, relating a predominant sound symbolic distinction (vowel frontness) to a novel associate (spatial proximity) in five studies. We show that changing one vowel in a label can influence estimations of distance, impacting judgment, perception, and action. The results (1) provide the first experimental support for a relationship between vowels and spatial distance and (2) demonstrate that sound-to-meaning mappings have outcomes that extend beyond just language and can - through a single sound - influence how we perceive and behave toward objects in the world. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Geodetic distance measuring apparatus

    NASA Technical Reports Server (NTRS)

    Abshire, J. B. (Inventor)

    1983-01-01

    A mode locked laser system including a laser device and its peripheral components is utilized for deriving two mutually phase locked optical wavelength signals and one phase locked microwave CW signal which respectively traverse the same distance measurement path. Preferably the optical signals are comprised of pulse type signals. Phase comparison of the two optical wavelength pulse signals is used to provide a measure of the dry air density while phase comparison of one of the optical wavelength pulse signals and the microwave CW signal is used to provide a measure of the wet or water vapor density of the air. From these measurements is computed in means of the distance to be measured corrected for the atmospheric dry and water vapor densities in the measurement path.

  9. Novae as distance indicators

    NASA Technical Reports Server (NTRS)

    Ford, Holland C.; Ciardullo, Robin

    1988-01-01

    Nova shells are characteristically prolate with equatorial bands and polar caps. Failure to account for the geometry can lead to large errors in expansion parallaxes for individual novae. When simple prescriptions are used for deriving expansion parallaxes from an ensemble of randomly oriented prolate spheroids, the average distance will be too small by factors of 10 to 15 percent. The absolute magnitudes of the novae will be underestimated and the resulting distance scale will be too small by the same factors. If observations of partially resolved nova shells select for large inclinations, the systematic error in the resulting distance scale could easily be 20 to 30 percent. Extinction by dust in the bulge of M31 may broaden and shift the intrinsic distribution of maximum nova magnitudes versus decay rates. We investigated this possibility by projecting Arp's and Rosino's novae onto a composite B - 6200A color map of M31's bulge. Thirty two of the 86 novae projected onto a smooth background with no underlying structure due to the presence of a dust cloud along the line of sight. The distribution of maximum magnitudes versus fade rates for these unreddened novae is indistinguishable from the distribution for the entire set of novae. It is concluded that novae suffer very little extinction from the filamentary and patchy distribution of dust seen in the bulge of M31. Time average B and H alpha nova luminosity functions are potentially powerful new ways to use novae as standard candles. Modern CCD observations and the photographic light curves of M31 novae found during the last 60 years were analyzed to show that these functions are power laws. Consequently, unless the eruption times for novae are known, the data cannot be used to obtain distances.

  10. Evaluating linguistic distance measures

    NASA Astrophysics Data System (ADS)

    Wichmann, Søren; Holman, Eric W.; Bakker, Dik; Brown, Cecil H.

    2010-09-01

    In Ref. [13], Petroni and Serva discuss the use of Levenshtein distances (LD) between words referring to the same concepts as a tool for establishing overall distances among languages which can then subsequently be used to derive phylogenies. The authors modify the raw LD by dividing the LD by the length of the longer of the two words compared, to produce what could be called LDN (normalized LD). Other scholars [7,8] have used a further modification, where they divide the LDN by the average LDN among words not referring to the same concept. This produces what could be called LDND. The authors of Ref. [13] question whether LDND is a more adequate measure of distance than LDN. Here we show empirically that LDND is the better measure in the situation where the languages compared have not already been shown, by other, more traditional methods of comparative linguistics, to be related. If automated language classification is to be used as a tool independent of traditional methods then the further modification is necessary.

  11. Nutrition for distance events.

    PubMed

    Burke, Louise M; Millet, Gregoire; Tarnopolsky, Mark A

    2007-01-01

    The goal of training is to prepare the distance athlete to perform at his or her best during major competitions. Whatever the event, nutrition plays a major role in the achievement of various factors that will see a runner or walker take the starting line in the best possible form. Everyday eating patterns must supply fuel and nutrients needed to optimize their performance during training sessions and to recover quickly afterwards. Carbohydrate and fluid intake before, during, and after a workout may help to reduce fatigue and enhance performance. Recovery eating should also consider issues for adaptation and the immune system that may involve intakes of protein and some micronutrients. Race preparation strategies should include preparation of adequate fuel stores, including carbohydrate loading for prolonged events such as the marathon or 50-km walk. Fluid and carbohydrate intake during races lasting an hour or more should also be considered. Sports foods and supplements of value to distance athletes include sports drinks and liquid meal supplements to allow nutrition goals to be achieved when normal foods are not practical. While caffeine is an ergogenic aid of possible value to distance athletes, most other supplements are of minimal benefit.

  12. A Gap in TW Hydrae's Disk

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-01-01

    Located a mere 176 light-years away, TW Hydrae is an 8-million-year-old star surrounded by a nearly face-on disk of gas and dust. Recent observations have confirmed the existence of a gap within that disk a particularly intriguing find, since gaps can sometimes signal the presence of a planet.Gaps and PlanetsNumerical simulations have shown that newly-formed planets orbiting within dusty disks can clear the gas and dust out of their paths. This process results in pressure gradients that can be seen in the density structure of the disk, in the form of visible gaps, rings, or spirals.For this reason, finding a gap in a protoplanetary disk can be an exciting discovery. Previous observations of the disk around TW Hydrae had indicated that there might be a gap present, but they were limited in their resolution; despite TW Hydraes relative nearness, attempting to observe the dim light scattered off dust particles in a disk surrounding a distant, bright star is difficult!But a team led by Valerie Rapson (Rochester Institute of Technology, Dudley Observatory) recently set out to follow up on this discovery using a powerful tool: the Gemini Planet Imager (GPI).New ObservationsComparison of the actual image of TW Hydraes disk from GPI (right) to a simulated scattered-light image from a model of a ~0.2 Jupiter-mass planet orbiting in the disk at ~21 AU (left) in two different bands (top: J, bottom: K1).[Adapted from Rapson et al. 2015]GPI is an instrument on the Gemini South Telescope in Chile. Its near-infrared imagers, equipped with extreme adaptive optics, allowed it to probe the disk from ~80 AU all the way in to ~10 AU from the central star, with an unprecedented resolution of ~1.5 AU.These observations from GPI allowed Rapson and collaborators to unambiguously confirm the presence of a gap in TW Hydraes disk. The gap lies at a distance of ~23 AU from the central star (roughly the same distance as Uranus to the Sun), and its ~5 AU wide.Modeled PossibilitiesThere are a

  13. Estimating Gender Wage Gaps

    ERIC Educational Resources Information Center

    McDonald, Judith A.; Thornton, Robert J.

    2011-01-01

    Course research projects that use easy-to-access real-world data and that generate findings with which undergraduate students can readily identify are hard to find. The authors describe a project that requires students to estimate the current female-male earnings gap for new college graduates. The project also enables students to see to what…

  14. The Academic Generation Gap

    ERIC Educational Resources Information Center

    Dronzek, Anna

    2008-01-01

    The current generation gap in academia is different--fundamentally shaped by the structural problems of academic employment. The job market has especially exacerbated tensions between senior and junior faculty by ratcheting up expectations and requirements at every stage of the academic career. The disparities have been mentioned often enough to…

  15. Multiple gap photovoltaic device

    DOEpatents

    Dalal, Vikram L.

    1981-01-01

    A multiple gap photovoltaic device having a transparent electrical contact adjacent a first cell which in turn is adjacent a second cell on an opaque electrical contact, includes utilizing an amorphous semiconductor as the first cell and a crystalline semiconductor as the second cell.

  16. Gaining on the Gap

    ERIC Educational Resources Information Center

    Smith, Robert G.

    2010-01-01

    About three-quarters of the 2009 graduates of the highly diverse Arlington, Virginia, Public Schools completed one or more Advanced Placement or International Baccalaureate courses during their high school careers. That figure serves as one indicator of a decade-long initiative to eliminate achievement gaps while raising achievement for all…

  17. Confronting the Autonomy Gap

    ERIC Educational Resources Information Center

    Adamowski, Steven; Petrilli, Michael J.

    2007-01-01

    "The Autonomy Gap," a recent study by the American Institute for Research and the Thomas B. Fordham Institute, found that many public elementary school principals feel constrained by a bureaucracy that impedes their ability to raise student achievement. Unfortunately, those principals are still held accountable for their school's results--even…

  18. The Academic Generation Gap

    ERIC Educational Resources Information Center

    Dronzek, Anna

    2008-01-01

    The current generation gap in academia is different--fundamentally shaped by the structural problems of academic employment. The job market has especially exacerbated tensions between senior and junior faculty by ratcheting up expectations and requirements at every stage of the academic career. The disparities have been mentioned often enough to…

  19. Confronting the Autonomy Gap

    ERIC Educational Resources Information Center

    Adamowski, Steven; Petrilli, Michael J.

    2007-01-01

    "The Autonomy Gap," a recent study by the American Institute for Research and the Thomas B. Fordham Institute, found that many public elementary school principals feel constrained by a bureaucracy that impedes their ability to raise student achievement. Unfortunately, those principals are still held accountable for their school's results--even…

  20. Structuring the Information Gap.

    ERIC Educational Resources Information Center

    Edge, Julian

    1984-01-01

    Describes an information gap procedure to teach a new structure which requires students to look for and exchange information in order to complete a task in an English as a second language class. Illustrates the method with a set of materials and suggests ways for teachers to produce similar materials. (SED)

  1. Rho GAPs and GEFs

    PubMed Central

    van Buul, Jaap D; Geerts, Dirk; Huveneers, Stephan

    2014-01-01

    Within blood vessels, endothelial cell–cell and cell–matrix adhesions are crucial to preserve barrier function, and these adhesions are tightly controlled during vascular development, angiogenesis, and transendothelial migration of inflammatory cells. Endothelial cellular signaling that occurs via the family of Rho GTPases coordinates these cell adhesion structures through cytoskeletal remodelling. In turn, Rho GTPases are regulated by GTPase-activating proteins (GAPs) and guanine nucleotide exchange factors (GEFs). To understand how endothelial cells initiate changes in the activity of Rho GTPases, and thereby regulate cell adhesion, we will discuss the role of Rho GAPs and GEFs in vascular biology. Many potentially important Rho regulators have not been studied in detail in endothelial cells. We therefore will first overview which GAPs and GEFs are highly expressed in endothelium, based on comparative gene expression analysis of human endothelial cells compared with other tissue cell types. Subsequently, we discuss the relevance of Rho GAPs and GEFs for endothelial cell adhesion in vascular homeostasis and disease. PMID:24622613

  2. Estimating Gender Wage Gaps

    ERIC Educational Resources Information Center

    McDonald, Judith A.; Thornton, Robert J.

    2011-01-01

    Course research projects that use easy-to-access real-world data and that generate findings with which undergraduate students can readily identify are hard to find. The authors describe a project that requires students to estimate the current female-male earnings gap for new college graduates. The project also enables students to see to what…

  3. STEMMING the Gap

    ERIC Educational Resources Information Center

    Kahler, Jim; Valentine, Nancy

    2011-01-01

    America has a gap when it comes to youth pursuing science and technology careers. In an effort to improve the knowledge and application of science, technology, engineering, and math (STEM), after-school programs can work in conjunction with formal in-school curriculum to improve science education. One organization that actively addresses this…

  4. Bridge the Gap.

    ERIC Educational Resources Information Center

    Klein, Mel; Cufaude, Jeffrey B.

    1989-01-01

    This document consists of two paired articles: the first, "Preparing Faculty Out of Class Experiences," by Mel Klein, and the second, "Help Advisers Be More Than Ghost Signatures," by Jeffrey B. Calfaude. Each article shares insights on how faculty advisers "bridge the gap" between students and faculty. When faculty members are asked to advise…

  5. Bridging a Communication Gap

    ERIC Educational Resources Information Center

    Kahn, Ethel

    1972-01-01

    Description of a community program in cooperation with a regional extension service. The goals were to explore the generation gap, and conflict in life values, understand family role, increase self awareness, improve adult-youth communication, and understand the individual and his relationship to basic social principles. (Author/JB)

  6. Bridging the Development Gap.

    DTIC Science & Technology

    1999-11-01

    Bridging the Development Gap is contractual cooperative agreement between Mercury Computer Systems, Inc. and DARPA. This program was developed...processing, interfacing with I/O devices, memory constraints, as well as real-time throughput and latency challenges. Mercury has bridged the indicated

  7. Featured Image: A Gap in TW Hydrae

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-04-01

    This remarkable image (click for the full view!) is a high-resolution map of the 870 m light emitted by the protoplanetary disk surrounding the young solar analog TW Hydrae. A recent study led by Sean Andrews (Harvard-Smithsonian Center for Astrophysics) presents these observations, obtained with the long-baseline configuration of the Atacama Large Millimeter/submillimeter Array (ALMA) at an unprecedented spatial resolution of ~1 AU. The data represent the distribution of millimeter-sized dust grains in this disk, revealing a beautiful concentric ring structure out to a radial distance of 60 AU from the host star. The apparent gaps in the disk could have anyof three origins:Chemical: apparent gaps can becaused by condensation fronts of volatilesMagnetic: apparent gaps can becaused by radial magnetic pressure variationsDynamic: actual gaps can becaused by the clearing of dust by young planets.For more information, check out the paper below!CitationSean M. Andrews et al 2016 ApJ 820 L40. doi:10.3847/2041-8205/820/2/L40

  8. Spark gap device for precise switching

    DOEpatents

    Boettcher, Gordon E.

    1984-01-01

    A spark gap device for precise switching of an energy storage capacitor into an exploding bridge wire load is disclosed. Niobium electrodes having a melting point of 2,415 degrees centrigrade are spaced apart by an insulating cylinder to define a spark gap. The electrodes are supported by conductive end caps which, together with the insulating cylinder, form a hermetically sealed chamber filled with an inert, ionizable gas, such as pure xenon. A quantity of solid radioactive carbon-14 within the chamber adjacent the spark gap serves as a radiation stabilizer. The sides of the electrodes and the inner wall of the insulating cylinder are spaced apart a sufficient distance to prevent unwanted breakdown initiation. A conductive sleeve may envelop the outside of the insulating member from the midpoint of the spark gap to the cap adjacent the cathode. The outer metallic surfaces of the device may be coated with a hydrogen-impermeable coating to lengthen the shelf life and operating life of the device. The device breaks down at about 1,700 volts for input voltage rates up to 570 volts/millisecond and allows peak discharge currents of up to 3,000 amperes from a 0.3 microfarad energy storage capacitor for more than 1,000 operations.

  9. Spark gap device for precise switching

    DOEpatents

    Boettcher, G.E.

    1984-10-02

    A spark gap device for precise switching of an energy storage capacitor into an exploding bridge wire load is disclosed. Niobium electrodes having a melting point of 2,415 degrees centigrade are spaced apart by an insulating cylinder to define a spark gap. The electrodes are supported by conductive end caps which, together with the insulating cylinder, form a hermetically sealed chamber filled with an inert, ionizable gas, such as pure xenon. A quantity of solid radioactive carbon-14 within the chamber adjacent the spark gap serves as a radiation stabilizer. The sides of the electrodes and the inner wall of the insulating cylinder are spaced apart a sufficient distance to prevent unwanted breakdown initiation. A conductive sleeve may envelop the outside of the insulating member from the midpoint of the spark gap to the cap adjacent the cathode. The outer metallic surfaces of the device may be coated with a hydrogen-impermeable coating to lengthen the shelf life and operating life of the device. The device breaks down at about 1,700 volts for input voltage rates up to 570 volts/millisecond and allows peak discharge currents of up to 3,000 amperes from a 0.3 microfarad energy storage capacitor for more than 1,000 operations. 3 figs.

  10. Distance to Dark Bodies

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Using the unique orbit of NASA's Spitzer Space Telescope and a depth-perceiving trick called parallax, astronomers have determined the distance to an invisible Milky Way object called OGLE-2005-SMC-001. This artist's concept illustrates how this trick works: different views from both Spitzer and telescopes on Earth are combined to give depth perception.

    Our Milky Way galaxy is heavier than it looks, and scientists use the term 'dark matter' to describe all the 'heavy stuff' in the universe that seems to be present but invisible to our telescopes. While much of this dark matter is likely made up of exotic materials, different from the ordinary particles that make up the world around us, some may consist of dark celestial bodies -- like planets, black holes, or failed stars -- that do not produce light or are too faint to detect from Earth. OGLE-2005-SMC-001 is one of these dark celestial bodies.

    Although astronomers cannot see a dark body, they can sense its presence from the way light acts around it. When a dark body like OGLE-2005-SMC-001 passes in front of a bright star, its gravity causes the background starlight to bend and brighten, a process called gravitational microlensing. When the observing telescope, dark body, and star system are closely aligned, the microlensing event reaches maximum, or peak, brightness.

    A team of astronomers first sensed OGLE-2005-SMC-001's presence when it passed in front of a star in a neighboring satellite galaxy called the Small Magellanic Cloud. In this artist's rendering, the satellite galaxy is depicted as the fuzzy structure sitting to the left of Earth. Once they detected this microlensing event, the scientists used Spitzer and the principle of parallax to figure out its distance. Humans naturally use parallax to determine distance. Each eye sees the distance of an object differently. The brain takes each eye's perspective and instantaneously calculates how far away the object is.

    To determine OGLE

  11. Distance to Dark Bodies

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Using the unique orbit of NASA's Spitzer Space Telescope and a depth-perceiving trick called parallax, astronomers have determined the distance to an invisible Milky Way object called OGLE-2005-SMC-001. This artist's concept illustrates how this trick works: different views from both Spitzer and telescopes on Earth are combined to give depth perception.

    Our Milky Way galaxy is heavier than it looks, and scientists use the term 'dark matter' to describe all the 'heavy stuff' in the universe that seems to be present but invisible to our telescopes. While much of this dark matter is likely made up of exotic materials, different from the ordinary particles that make up the world around us, some may consist of dark celestial bodies -- like planets, black holes, or failed stars -- that do not produce light or are too faint to detect from Earth. OGLE-2005-SMC-001 is one of these dark celestial bodies.

    Although astronomers cannot see a dark body, they can sense its presence from the way light acts around it. When a dark body like OGLE-2005-SMC-001 passes in front of a bright star, its gravity causes the background starlight to bend and brighten, a process called gravitational microlensing. When the observing telescope, dark body, and star system are closely aligned, the microlensing event reaches maximum, or peak, brightness.

    A team of astronomers first sensed OGLE-2005-SMC-001's presence when it passed in front of a star in a neighboring satellite galaxy called the Small Magellanic Cloud. In this artist's rendering, the satellite galaxy is depicted as the fuzzy structure sitting to the left of Earth. Once they detected this microlensing event, the scientists used Spitzer and the principle of parallax to figure out its distance. Humans naturally use parallax to determine distance. Each eye sees the distance of an object differently. The brain takes each eye's perspective and instantaneously calculates how far away the object is.

    To determine OGLE

  12. Advanced hierarchical distance sampling

    USGS Publications Warehouse

    Royle, Andy

    2016-01-01

    In this chapter, we cover a number of important extensions of the basic hierarchical distance-sampling (HDS) framework from Chapter 8. First, we discuss the inclusion of “individual covariates,” such as group size, in the HDS model. This is important in many surveys where animals form natural groups that are the primary observation unit, with the size of the group expected to have some influence on detectability. We also discuss HDS integrated with time-removal and double-observer or capture-recapture sampling. These “combined protocols” can be formulated as HDS models with individual covariates, and thus they have a commonality with HDS models involving group structure (group size being just another individual covariate). We cover several varieties of open-population HDS models that accommodate population dynamics. On one end of the spectrum, we cover models that allow replicate distance sampling surveys within a year, which estimate abundance relative to availability and temporary emigration through time. We consider a robust design version of that model. We then consider models with explicit dynamics based on the Dail and Madsen (2011) model and the work of Sollmann et al. (2015). The final major theme of this chapter is relatively newly developed spatial distance sampling models that accommodate explicit models describing the spatial distribution of individuals known as Point Process models. We provide novel formulations of spatial DS and HDS models in this chapter, including implementations of those models in the unmarked package using a hack of the pcount function for N-mixture models.

  13. Distance Metric Tracking

    DTIC Science & Technology

    2016-03-02

    520, 2004. 16 [12] E.C. Hall and R.M. Willett. Online convex optimization in dynamic environ- ments. Selected Topics in Signal Processing, IEEE Journal...Conference on Machine Learning, pages 1160–1167. ACM, 2008. [25] Eric P Xing, Michael I Jordan, Stuart Russell, and Andrew Y Ng. Distance metric...whereBψ is any Bregman divergence and ηt is the learning rate parameter. From ( Hall & Willett, 2015) we have: Theorem 1. G` = max θ∈Θ,`∈L ‖∇f(θ)‖ φmax = 1

  14. Deterministic multidimensional nonuniform gap sampling.

    PubMed

    Worley, Bradley; Powers, Robert

    2015-12-01

    Born from empirical observations in nonuniformly sampled multidimensional NMR data relating to gaps between sampled points, the Poisson-gap sampling method has enjoyed widespread use in biomolecular NMR. While the majority of nonuniform sampling schemes are fully randomly drawn from probability densities that vary over a Nyquist grid, the Poisson-gap scheme employs constrained random deviates to minimize the gaps between sampled grid points. We describe a deterministic gap sampling method, based on the average behavior of Poisson-gap sampling, which performs comparably to its random counterpart with the additional benefit of completely deterministic behavior. We also introduce a general algorithm for multidimensional nonuniform sampling based on a gap equation, and apply it to yield a deterministic sampling scheme that combines burst-mode sampling features with those of Poisson-gap schemes. Finally, we derive a relationship between stochastic gap equations and the expectation value of their sampling probability densities. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Making the Invisible Visible: Personas and Mental Models of Distance Education Library Users

    ERIC Educational Resources Information Center

    Lewis, Cynthia; Contrino, Jacline

    2016-01-01

    Gaps between users' and designers' mental models of digital libraries often result in adverse user experiences. This article details an exploratory user research study at a large, predominantly online university serving non-traditional distance education students with the goal of understanding these gaps. Using qualitative data, librarians created…

  16. Making the Invisible Visible: Personas and Mental Models of Distance Education Library Users

    ERIC Educational Resources Information Center

    Lewis, Cynthia; Contrino, Jacline

    2016-01-01

    Gaps between users' and designers' mental models of digital libraries often result in adverse user experiences. This article details an exploratory user research study at a large, predominantly online university serving non-traditional distance education students with the goal of understanding these gaps. Using qualitative data, librarians created…

  17. Review and Content Analysis of the "International Review of Research in Open and Distance/Distributed Learning" (2000-2015)

    ERIC Educational Resources Information Center

    Zawacki-Richter, Olaf; Alturki, Uthman; Aldraiweesh, Ahmed

    2017-01-01

    This paper presents a review of distance education literature published in the "International Review of Research in Open and Distance/Distributed Learning" (IRRODL) to describe the status thereof and to identify gaps and priority areas in distance education research based on a validated classification of research areas. All articles (N =…

  18. New Ways of Learning: Comparing the Effectiveness of Interactive Online Media in Distance Education with the European Textbook Tradition

    ERIC Educational Resources Information Center

    Krämer, Bernd J.; Neugebauer, Jonas; Magenheim, Johannes; Huppertz, Helga

    2015-01-01

    Although many innovations exploiting web technologies have been suggested in distance higher education, very little original research exists investigating the impact of web-based learning environments on distance students' learning processes and outcomes. To close this gap, four sets of data have been collected in a distance-learning course:…

  19. New Ways of Learning: Comparing the Effectiveness of Interactive Online Media in Distance Education with the European Textbook Tradition

    ERIC Educational Resources Information Center

    Krämer, Bernd J.; Neugebauer, Jonas; Magenheim, Johannes; Huppertz, Helga

    2015-01-01

    Although many innovations exploiting web technologies have been suggested in distance higher education, very little original research exists investigating the impact of web-based learning environments on distance students' learning processes and outcomes. To close this gap, four sets of data have been collected in a distance-learning course:…

  20. Mind the Gap

    ERIC Educational Resources Information Center

    Bannon, Thomas J.; Bradley, Robert E.

    2008-01-01

    If you break a stick at two random places, the probability that the three pieces form a triangle is 1/4. How does this generalize? To answer this question, we give a method for finding the probability that n randomly chosen points in a given interval fall within a specified distance of one another. We use this method to provide solutions to…

  1. Time-Distance Helioseismology

    NASA Technical Reports Server (NTRS)

    Duvall, Thomas L., Jr.

    2010-01-01

    Time-distance helioseismology is a method of ambient noise imaging using the solar oscillations. The basic realization that led to time-distance helioseismology was that the temporal cross correlation of the signals at two 'surface' (or photospheric) locations should show a feature at the time lag corresponding to the subsurface travel time between the locations. The temporal cross correlation, as a function of the location separation, is the Fourier transform of the spatio-temporal power spectrum of the solar oscillations, a commonly used function in helioseismology. It is therefore likely the characteristic ridge structure of the correlation function had been seen before without appreciation of its significance. Travel times are measured from the cross correlations. The times are sensitive to a number of important subsurface solar phenomena. These include sound speed variations, flows, and magnetic fields. There has been much interesting progress in the 17 years since the first paper on this subject (Duvall et al., Nature, 1993, 362, 430-432). This progress will be reviewed in this paper.

  2. Distance collaborations with industry

    SciTech Connect

    Peskin, A.; Swyler, K.

    1998-06-01

    The college industry relationship has been identified as a key policy issue in Engineering Education. Collaborations between academic institutions and the industrial sector have a long history and a bright future. For Engineering and Engineering Technology programs in particular, industry has played a crucial role in many areas including advisement, financial support, and practical training of both faculty and students. Among the most important and intimate interactions are collaborative projects and formal cooperative education arrangements. Most recently, such collaborations have taken on a new dimension, as advances in technology have made possible meaningful technical collaboration at a distance. There are several obvious technology areas that have contributed significantly to this trend. Foremost is the ubiquitous presence of the Internet. Perhaps almost as important are advances in computer based imaging. Because visual images offer a compelling user experience, it affords greater knowledge transfer efficiency than other modes of delivery. Furthermore, the quality of the image appears to have a strongly correlated effect on insight. A good visualization facility offers both a means for communication and a shared information space for the subjects, which are among the essential features of both peer collaboration and distance learning.

  3. 40 CFR Appendixes A-K to Part 51 - [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 2 2010-07-01 2010-07-01 false A Appendixes A-K to Part 51 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS REQUIREMENTS FOR PREPARATION, ADOPTION, AND SUBMITTAL OF IMPLEMENTATION PLANS Appendixes A-K to Part 51...

  4. Variable Gap Conjugated Polymers

    DTIC Science & Technology

    2005-12-01

    conducting gold interfacial layer interjected between the ITO glass electrode and the PEDOT/PSS hole transport layer . A family of low band gap, and near IR...which can be used as both electrochromics and as the hole transport layers in light emitting diodes. Hybrid electrochromic and electroluminescent (EC...MEH-PPV, P3HT, etc.) in order to blanket the solar spectrum. Initial device results on these multi-component blends are promising. In addition, we

  5. Minding the Gap

    SciTech Connect

    Firestone, Millicent Anne

    2015-02-23

    Neutron & X-ray scattering provides nano- to meso-scale details of complex fluid structure; 1D electronic density maps dervied from SAXS yield molecular level insights; Neutron reflectivity provides substructure details of substrate supported complex fluids; Complex fluids composition can be optimized to support a wide variety of both soluble and membrane proteins; The water gap dimensions can be finely tuned through polymer component.

  6. Air-gap heterostructures

    NASA Astrophysics Data System (ADS)

    Heyn, Ch.; Schmidt, M.; Schwaiger, S.; Stemmann, A.; Mendach, S.; Hansen, W.

    2011-01-01

    We demonstrate the fabrication of thin GaAs layers which quasi hover above the underlying GaAs substrate. The hovering layers have a perfect epitaxial relationship to the substrate crystal lattice and are connected to the substrate surface only by lattice matched nanopillars of low density. These air-gap heterostructures are created by combining in situ molecular beam epitaxy compatible self-assembled droplet-etching and ex situ selective wet-chemical etching.

  7. GapBlaster—A Graphical Gap Filler for Prokaryote Genomes

    PubMed Central

    Veras, Adonney; de Melo, Diego Magalhães; Soares, Siomar; Pinheiro, Kenny; Guimarães, Luis; Azevedo, Vasco; Silva, Artur; Ramos, Rommel T. J.

    2016-01-01

    The advent of NGS (Next Generation Sequencing) technologies has resulted in an exponential increase in the number of complete genomes available in biological databases. This advance has allowed the development of several computational tools enabling analyses of large amounts of data in each of the various steps, from processing and quality filtering to gap filling and manual curation. The tools developed for gap closure are very useful as they result in more complete genomes, which will influence downstream analyses of genomic plasticity and comparative genomics. However, the gap filling step remains a challenge for genome assembly, often requiring manual intervention. Here, we present GapBlaster, a graphical application to evaluate and close gaps. GapBlaster was developed via Java programming language. The software uses contigs obtained in the assembly of the genome to perform an alignment against a draft of the genome/scaffold, using BLAST or Mummer to close gaps. Then, all identified alignments of contigs that extend through the gaps in the draft sequence are presented to the user for further evaluation via the GapBlaster graphical interface. GapBlaster presents significant results compared to other similar software and has the advantage of offering a graphical interface for manual curation of the gaps. GapBlaster program, the user guide and the test datasets are freely available at https://sourceforge.net/projects/gapblaster2015/. It requires Sun JDK 8 and Blast or Mummer. PMID:27171416

  8. Jets from a Distance

    NASA Image and Video Library

    2017-07-17

    Enceladus' intriguing south-polar jets are viewed from afar, backlit by sunlight while the moon itself glows softly in reflected Saturn-shine. Observations of the jets taken from various viewing geometries provide different insights into these remarkable features. Cassini has gathered a wealth of information in the hopes of unraveling the mysteries of the subsurface ocean that lurks beneath the moon's icy crust. This view looks toward the Saturn-facing hemisphere of Enceladus (313 miles or 504 kilometers across). North is up. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on April 13, 2017. The view was acquired at a distance of approximately 502,000 miles (808,000 kilometers) from Enceladus and at a sun-Enceladus-spacecraft, or phase, angle of 176 degrees. Image scale is 3 miles (5 kilometers) per pixel. https://photojournal.jpl.nasa.gov/catalog/PIA21338

  9. Algebraic distance on graphs.

    SciTech Connect

    Chen, J.; Safro, I.

    2011-01-01

    Measuring the connection strength between a pair of vertices in a graph is one of the most important concerns in many graph applications. Simple measures such as edge weights may not be sufficient for capturing the effects associated with short paths of lengths greater than one. In this paper, we consider an iterative process that smooths an associated value for nearby vertices, and we present a measure of the local connection strength (called the algebraic distance; see [D. Ron, I. Safro, and A. Brandt, Multiscale Model. Simul., 9 (2011), pp. 407-423]) based on this process. The proposed measure is attractive in that the process is simple, linear, and easily parallelized. An analysis of the convergence property of the process reveals that the local neighborhoods play an important role in determining the connectivity between vertices. We demonstrate the practical effectiveness of the proposed measure through several combinatorial optimization problems on graphs and hypergraphs.

  10. Reconsidering Moore's Transactional Distance Theory

    ERIC Educational Resources Information Center

    Giossos, Yiannis; Koutsouba, Maria; Lionarakis, Antonis; Skavantzos, Kosmas

    2009-01-01

    One of the core theories of distance education is Michael Graham Moore's "Theory of Transactional Distance" that provides the broad framework of the pedagogy of distance education and allows the generation of almost infinite number of hypotheses for research. However, the review of the existing studies relating to the theory showed the use of a…

  11. Interactive Distance Learning in Connecticut.

    ERIC Educational Resources Information Center

    Pietras, Jesse John; Murphy, Robert J.

    This paper provides an overview of distance learning activities in Connecticut and addresses the feasibility of such activities. Distance education programs have evolved from the one dimensional electronic mail systems to the use of sophisticated digital fiber networks. The Middlesex Distance Learning Consortium has developed a long-range plan to…

  12. Teleteaching Distance Education. Final Report.

    ERIC Educational Resources Information Center

    Mansfield Univ., PA. Rural Services Inst.

    This study investigated the need for distance learning in Pennsylvania's rural schools, examined types of distance learning programs and technology currently being used, and identified factors that could enhance or inhibit the use of distance learning in rural schools. Data collection included (1) a literature search, (2) surveys administered to…

  13. Interactive Distance Learning in Connecticut.

    ERIC Educational Resources Information Center

    Pietras, Jesse John; Murphy, Robert J.

    This paper provides an overview of distance learning activities in Connecticut and addresses the feasibility of such activities. Distance education programs have evolved from the one dimensional electronic mail systems to the use of sophisticated digital fiber networks. The Middlesex Distance Learning Consortium has developed a long-range plan to…

  14. DISTANCES TO DARK CLOUDS: COMPARING EXTINCTION DISTANCES TO MASER PARALLAX DISTANCES

    SciTech Connect

    Foster, Jonathan B.; Jackson, James M.; Stead, Joseph J.; Hoare, Melvin G.; Benjamin, Robert A. E-mail: jackson@bu.edu E-mail: mgh@ast.leeds.ac.uk

    2012-06-01

    We test two different methods of using near-infrared extinction to estimate distances to dark clouds in the first quadrant of the Galaxy using large near-infrared (Two Micron All Sky Survey and UKIRT Infrared Deep Sky Survey) surveys. Very long baseline interferometry parallax measurements of masers around massive young stars provide the most direct and bias-free measurement of the distance to these dark clouds. We compare the extinction distance estimates to these maser parallax distances. We also compare these distances to kinematic distances, including recent re-calibrations of the Galactic rotation curve. The extinction distance methods agree with the maser parallax distances (within the errors) between 66% and 100% of the time (depending on method and input survey) and between 85% and 100% of the time outside of the crowded Galactic center. Although the sample size is small, extinction distance methods reproduce maser parallax distances better than kinematic distances; furthermore, extinction distance methods do not suffer from the kinematic distance ambiguity. This validation gives us confidence that these extinction methods may be extended to additional dark clouds where maser parallaxes are not available.

  15. Online Penalty: The Impact of Online Instruction on the Latino-White Achievement Gap

    ERIC Educational Resources Information Center

    Kaupp, Ray

    2012-01-01

    Despite a substantial body of research on the effectiveness of distance education at the post-secondary level, little is known about the impact of online course delivery on the achievement gap. In California, the gap between white and Latino post-secondary student outcomes is significant and persistent, with Latino students overrepresented in…

  16. Online Penalty: The Impact of Online Instruction on the Latino-White Achievement Gap

    ERIC Educational Resources Information Center

    Kaupp, Ray

    2012-01-01

    Despite a substantial body of research on the effectiveness of distance education at the post-secondary level, little is known about the impact of online course delivery on the achievement gap. In California, the gap between white and Latino post-secondary student outcomes is significant and persistent, with Latino students overrepresented in…

  17. Skills Gaps in Australian Firms

    ERIC Educational Resources Information Center

    Lindorff, Margaret

    2011-01-01

    This paper reports the results of a survey of more than 2000 managers examining perceptions of skills gaps in a range of Australian firms. It finds that three quarters report a skills gap, and almost one third report skills gaps across the whole organisation. Firm size and industry differences exist in perceptions of the effect of the skills gap…

  18. SOUTHWEST REGIONAL GAP LAND COVER

    EPA Science Inventory

    The Gap Analysis Program is a national inter-agency program that maps the distribution

    of plant communities and selected animal species and compares these distributions with land

    stewardship to identify gaps in biodiversity protection. GAP uses remote satellite imag...

  19. SOUTHWEST REGIONAL GAP LAND COVER

    EPA Science Inventory

    The Gap Analysis Program is a national inter-agency program that maps the distribution

    of plant communities and selected animal species and compares these distributions with land

    stewardship to identify gaps in biodiversity protection. GAP uses remote satellite imag...

  20. Skills Gaps in Australian Firms

    ERIC Educational Resources Information Center

    Lindorff, Margaret

    2011-01-01

    This paper reports the results of a survey of more than 2000 managers examining perceptions of skills gaps in a range of Australian firms. It finds that three quarters report a skills gap, and almost one third report skills gaps across the whole organisation. Firm size and industry differences exist in perceptions of the effect of the skills gap…

  1. Predicting protein submitochondrial locations using a K-Nearest neighbor method based on the Bit-Score weighted euclidean distance

    USDA-ARS?s Scientific Manuscript database

    Mitochondria are essential subcellular organelles found in eukaryotic cells. Knowing information on a protein’s subcellular or sub subcellular location provides in-depth insights about the microenvironment where it interacts with other molecules and is crucial for inferring the protein’s function. T...

  2. An Algorithm to Find a K5 Minor

    DTIC Science & Technology

    1991-02-01

    February 1991 UILU-ENG-91-2212 ACT-117 Applied Computagion Theory AD-A232 901 AN ALGORITHM TO FIND A K5 MINOR P. J. McGuinness A. E. KezdyI DTIC...algorithm to find a K 5 minor Patrick J. McGuinness and Andr6 E. Kdzdy Abstract We present an 0(n 2) algorithm that, given a graph, either returns a K, minor...describe parallel algorithms to find Kuratowski homeomorphs and K3,3 homeomorphs, when such homeomorphs are present. Extending Kuratowski’s result, Wagner

  3. Supportive learning in distance education.

    PubMed

    Lawton, S

    1997-05-01

    This paper argues that tutorial support should enhance the learning experience of students who enrol on a distance education programme. A rationale for such support is given as well as a definition of support for distance learners. The complex role of the tutor in distance learning is described which suggests the need for tutor preparation, particularly for tutors adapting to this mode of course delivery. The paper reports on two existing models used within distance education which have focused on the outcome of study. The paper introduces an alternative model of supportive learning which focuses on the development of the educational experience throughout the length of a distance-learning course.

  4. Action at a Distance

    PubMed Central

    Blobaum, Anna L.; Xu, Shu; Rowlinson, Scott W.; Duggan, Kelsey C.; Banerjee, Surajit; Kudalkar, Shalley N.; Birmingham, William R.; Ghebreselasie, Kebreab; Marnett, Lawrence J.

    2015-01-01

    Cyclooxygenase enzymes (COX-1 and COX-2) catalyze the conversion of arachidonic acid to prostaglandin G2. The inhibitory activity of rapid, reversible COX inhibitors (ibuprofen, naproxen, mefenamic acid, and lumiracoxib) demonstrated a significant increase in potency and time dependence of inhibition against double tryptophan murine COX-2 mutants at the 89/90 and 89/119 positions. In contrast, the slow, time-dependent COX inhibitors (diclofenac, indomethacin, and flurbiprofen) were unaffected by those mutations. Further mutagenesis studies suggested that mutation at position 89 was principally responsible for the changes in inhibitory potency of rapid, reversible inhibitors, whereas mutation at position 90 may exert some effect on the potency of COX-2-selective diarylheterocycle inhibitors; no effect was observed with mutation at position 119. Several crystal structures with or without NSAIDs indicated that placement of a bulky residue at position 89 caused a closure of a gap at the lobby, and alteration of histidine to tryptophan at position 90 changed the electrostatic profile of the side pocket of COX-2. Thus, these two residues, especially Val-89 at the lobby region, are crucial for the entrance and exit of some NSAIDs from the COX active site. PMID:25825493

  5. Mind the gap.

    SciTech Connect

    Bhagwat, M. S.; Krassnigg, A.; Maris, P.; Roberts, C. D.; Physics; Univ. Graz; Univ. of Pittsburgh

    2007-03-01

    In this summary of the application of Dyson-Schwinger equations to the theory and phenomenology of hadrons, some deductions following from a nonperturbative, symmetry-preserving truncation are highlighted, notable amongst which are results for pseudoscalar mesons. We also describe inferences from the gap equation relating to the radius of convergence of a chiral expansion, applications to heavy-light and heavy-heavy mesons, and quantitative estimates of the contribution of quark orbital angular momentum in pseudoscalar mesons; and recapitulate upon studies of nucleon electromagnetic form factors.

  6. The global drug gap.

    PubMed

    Reich, M R

    2000-03-17

    Global inequities in access to pharmaceutical products exist between rich and poor countries because of market and government failures as well as huge income differences. Multiple policies are required to address this global drug gap for three categories of pharmaceutical products: essential drugs, new drugs, and yet-to-be-developed drugs. Policies should combine "push" approaches of subsidies to support targeted drug development, "pull" approaches of financial incentives such as market guarantees, and "process" approaches aimed at improved institutional capacity. Constructive solutions are needed that can both protect the incentives for research and development and reduce the inequities of access.

  7. GAP-REACH

    PubMed Central

    Lewis-Fernández, Roberto; Raggio, Greer A.; Gorritz, Magdaliz; Duan, Naihua; Marcus, Sue; Cabassa, Leopoldo J.; Humensky, Jennifer; Becker, Anne E.; Alarcón, Renato D.; Oquendo, María A.; Hansen, Helena; Like, Robert C.; Weiss, Mitchell; Desai, Prakash N.; Jacobsen, Frederick M.; Foulks, Edward F.; Primm, Annelle; Lu, Francis; Kopelowicz, Alex; Hinton, Ladson; Hinton, Devon E.

    2015-01-01

    Growing awareness of health and health care disparities highlights the importance of including information about race, ethnicity, and culture (REC) in health research. Reporting of REC factors in research publications, however, is notoriously imprecise and unsystematic. This article describes the development of a checklist to assess the comprehensiveness and the applicability of REC factor reporting in psychiatric research publications. The 16-itemGAP-REACH© checklist was developed through a rigorous process of expert consensus, empirical content analysis in a sample of publications (N = 1205), and interrater reliability (IRR) assessment (N = 30). The items assess each section in the conventional structure of a health research article. Data from the assessment may be considered on an item-by-item basis or as a total score ranging from 0% to 100%. The final checklist has excellent IRR (κ = 0.91). The GAP-REACH may be used by multiple research stakeholders to assess the scope of REC reporting in a research article. PMID:24080673

  8. Improvement of luminous efficacy in plasma display panels by a counter-type electrode configuration with a large gap

    SciTech Connect

    Hur, Min; Kim, Jae Rok; Yi, Jeong Doo; Cho, Yoon Hyoung; Song, Su Bin; Park, Jun Yong; Lee, Han Yong

    2006-06-01

    The discharge characteristics of plasma display panel with coplanar and counter-type electrode configurations are compared using the numerical modeling and experiment with respect to real and macrocells, respectively. Numerical analysis shows that the ultraviolet (UV) efficiency and driving voltage of counter type at a gap distance of 230 {mu}m are located at similar levels to those of coplanar type at a gap distance of 60 {mu}m. The UV efficiency for counter type is enhanced with the rise of xenon fraction and gap distance, between which the large gap operation is more advantageous to high UV efficiency. The measured temporal evolution of infrared emission reveals that the cathode layer plays an important role in forming the discharge current after the gas breakdown. It is found from the time-averaged visible and infrared emissions for the counter type that as the gap distance becomes larger, the positive column region increases but the sheath regime remains almost unchanged. On the other hand, the variation of gap distance gives a little influence on the average discharge current at the same applied voltage. The UV efficiency is thus greatly improved with the gap distance. When the gap becomes double, the UV efficiency is improved by 75%, which is well agreed with the results predicted in the numerical modeling.

  9. A matter of distance

    NASA Image and Video Library

    2017-04-24

    In space, being outshone is an occupational hazard. This NASA/ESA Hubble Space Telescope image captures a galaxy named NGC 7250. Despite being remarkable in its own right — it has bright bursts of star formation and recorded supernova explosions — it blends into the background somewhat thanks to the gloriously bright star hogging the limelight next to it. This bright object is a single and little-studied star named TYC 3203-450-1, located in the constellation of Lacerta (The Lizard), much closer than the much more distant galaxy. Only this way a normal star can outshine an entire galaxy, consisting of billions of stars. Astronomers studying distant objects call these stars “foreground stars” and they are often not very happy about them, as their bright light is contaminating the faint light from the more distant and interesting objects they actually want to study. In this case TYC 3203-450-1 million times closer than NGC 7250 which lies over 45 million light-years away from us. Would the star be the same distance as NGC 7250, it would hardly be visible in this image.

  10. extinction-distances: Estimating distances to dark clouds

    NASA Astrophysics Data System (ADS)

    Foster, Jonathan

    2017-08-01

    Extinction-distances uses the number of foreground stars and a Galactic model of the stellar distribution to estimate the distance to dark clouds. It exploits the relatively narrow range of intrinsic near-infrared colors of stars to separate foreground from background stars. An advantage of this method is that the distribution of stellar colors in the Galactic model need not be precisely correct, only the number density as a function of distance from the Sun.

  11. New distances to RAVE stars

    NASA Astrophysics Data System (ADS)

    Binney, J.; Burnett, B.; Kordopatis, G.; McMillan, P. J.; Sharma, S.; Zwitter, T.; Bienaymé, O.; Bland-Hawthorn, J.; Steinmetz, M.; Gilmore, G.; Williams, M. E. K.; Navarro, J.; Grebel, E. K.; Helmi, A.; Parker, Q.; Reid, W. A.; Seabroke, G.; Watson, F.; Wyse, R. F. G.

    2014-01-01

    Probability density functions (pdfs) are determined from new stellar parameters for the distance moduli of stars for which the RAdial Velocity Experiment (RAVE) has obtained spectra with S/N ≥ 10. Single-Gaussian fits to the pdf in distance modulus suffice for roughly half the stars, with most of the other half having satisfactory two-Gaussian representations. As expected, early-type stars rarely require more than one Gaussian. The expectation value of distance is larger than the distance implied by the expectation of distance modulus; the latter is itself larger than the distance implied by the expectation value of the parallax. Our parallaxes of Hipparcos stars agree well with the values measured by Hipparcos, so the expectation of parallax is the most reliable distance indicator. The latter are improved by taking extinction into account. The effective temperature-absolute magnitude diagram of our stars is significantly improved when these pdfs are used to make the diagram. We use the method of kinematic corrections devised by Schönrich, Binney and Asplund to check for systematic errors for general stars and confirm that the most reliable distance indicator is the expectation of parallax. For cool dwarfs and low-gravity giants, <ϖ> tends to be larger than the true distance by up to 30 per cent. The most satisfactory distances are for dwarfs hotter than 5500 K. We compare our distances to stars in 13 open clusters with cluster distances from the literature and find excellent agreement for the dwarfs and indications that we are overestimating distances to giants, especially in young clusters.

  12. Distance education: the humanization of technology

    NASA Astrophysics Data System (ADS)

    Voelzke, Marcos Rincon; Rodrigues Ferreira, Orlando

    2015-08-01

    The Distance Education [DE] presents significant growth in graduates and postgraduates programs. Regarding this fact, new challenges arise and others must be considered, as the generation gap between digital immigrants and digital natives, the establishment of a population increasingly accustomed to Information and Communication Technologies [ICT] and teaching methodologies that should be used and developed. Vygotsky’s model of social interaction related to mediation can and should be used in DE, and concerning historical, social and cultural approaches affecting Brazilian reality, Paulo Freire is still up-to-date, integrating humanization into the use of ICT. This work only proceeds with analyses of these elements, being an excerpt of the master’s dissertation of one of the authors [Ferreira], under the guidance of another [Voelzke].

  13. Gap Opening in 3D: Single-planet Gaps

    NASA Astrophysics Data System (ADS)

    Fung, Jeffrey; Chiang, Eugene

    2016-12-01

    Giant planets can clear deep gaps when embedded in 2D (razor-thin) viscous circumstellar disks. We show by direct simulation that giant planets are just as capable of carving out gaps in 3D. Surface density maps are similar between 2D and 3D, even in detail. In particular, the scaling {{{Σ }}}{gap}\\propto {q}-2 of gap surface density with planet mass, derived from a global “zero-dimensional” balance of Lindblad and viscous torques, applies equally well to results obtained at higher dimensions. Our 3D simulations reveal extensive, near-sonic, meridional flows both inside and outside the gaps; these large-scale circulations might bear on disk compositional gradients, in dust or other chemical species. At high planet mass, gap edges are mildly Rayleigh unstable and intermittently shed streams of material into the gap—less so in 3D than in 2D.

  14. Band Gap Tuning of Armchair Graphene Nanoribbons by Using Antidotes

    NASA Astrophysics Data System (ADS)

    Zoghi, Milad; Goharrizi, Arash Yazdanpanah; Saremi, Mehdi

    2017-01-01

    The electronic properties of armchair graphene nanoribbons (AGNRs) can be changed by creating antidotes within the pristine ribbons and producing antidote super lattice AGNRs (ASL-AGNRs). In the present work, band gap tuning of ASL-AGNRs is investigated by varying the width of ribbons ( d W) and the distance between antidotes ( d L) for five different antidote topologies. Numerical tight-binding model is applied to obtain the band structure of the ribbons. Based on our results, it is found that the band gap of ASL-AGNRs can be increased or decreased in different cases. Furthermore, changing the width of ribbons generally results in more predictable␣band gap profiles compared to the variation of distance between antidotes. Consequently, by opting appropriate antidote topologies and dimensional parameters ( d W and d L), it is possible to gain a desired band gap size. This can be considered as an alternative solution in design of electronic and optoelectronic devices where tunable band gap values are needed.

  15. Undecidability of the spectral gap.

    PubMed

    Cubitt, Toby S; Perez-Garcia, David; Wolf, Michael M

    2015-12-10

    The spectral gap--the energy difference between the ground state and first excited state of a system--is central to quantum many-body physics. Many challenging open problems, such as the Haldane conjecture, the question of the existence of gapped topological spin liquid phases, and the Yang-Mills gap conjecture, concern spectral gaps. These and other problems are particular cases of the general spectral gap problem: given the Hamiltonian of a quantum many-body system, is it gapped or gapless? Here we prove that this is an undecidable problem. Specifically, we construct families of quantum spin systems on a two-dimensional lattice with translationally invariant, nearest-neighbour interactions, for which the spectral gap problem is undecidable. This result extends to undecidability of other low-energy properties, such as the existence of algebraically decaying ground-state correlations. The proof combines Hamiltonian complexity techniques with aperiodic tilings, to construct a Hamiltonian whose ground state encodes the evolution of a quantum phase-estimation algorithm followed by a universal Turing machine. The spectral gap depends on the outcome of the corresponding 'halting problem'. Our result implies that there exists no algorithm to determine whether an arbitrary model is gapped or gapless, and that there exist models for which the presence or absence of a spectral gap is independent of the axioms of mathematics.

  16. The Gap-Tpc

    NASA Astrophysics Data System (ADS)

    Rossi, B.; Anastasio, A.; Boiano, A.; Catalanotti, S.; Cocco, A. G.; Covone, G.; Di Meo, P.; Longo, G.; Vanzanella, A.; Walker, S.; Wang, H.; Wang, Y.; Fiorillo, G.

    2016-02-01

    Several experiments have been conducted worldwide, with the goal of observing low-energy nuclear recoils induced by WIMPs scattering off target nuclei in ultra-sensitive, low-background detectors. In the last few decades noble liquid detectors designed to search for dark matter in the form of WIMPs have been extremely successful in improving their sensitivities and setting the best limits. One of the crucial problems to be faced for the development of large size (multi ton-scale) liquid argon experiments is the lack of reliable and low background cryogenic PMTs: their intrinsic radioactivity, cost, and borderline performance at 87 K rule them out as a possible candidate for photosensors. We propose a brand new concept of liquid argon-based detector for direct dark matter search: the Geiger-mode Avalanche Photodiode Time Projection Chamber (GAP-TPC) optimized in terms of residual radioactivity of the photosensors, energy and spatial resolution, light and charge collection efficiency.

  17. Riparian canopy gaps: within-gap heating and downstream cooling

    NASA Astrophysics Data System (ADS)

    Jackson, C. R.; Coats, W. A.

    2016-12-01

    Summer stream temperatures are a primary determinant of stream habitat suitability for cold-water species. Trout, for example, are at the southern end of their range in the Southern Appalachian Mountains due to temperature constraints. Short and longwave radiation exchange with the atmosphere are the dominant drivers of spatial and temporal variability in stream temperatures. Consequently, when riparian forest cover is absent, stream temperatures rise until the outgoing longwave radiation (proportional to Tabs^4) matches the incoming shortwave. We have observed both rapid increases of daytime stream temperatures within riparian gaps and rapid declines of daytime stream temperatures after the stream returns to forested riparian conditions. Others have previously documented downstream cooling below riparian gaps, but with low replication. These previous case studies have found very different rates of cooling below gaps. To quantify and better understand cooling downstream of gaps, we measured temperatures above, within, and below 12 riparian gaps within and near the Upper Little Tennessee River basin in the Southern Appalachian Mountains of western North Carolina. Temperature responses to riparian cover changes varied widely. Below gaps, some streams cooled rapidly, some cooled slowly, and some continued to warm. The data suggest that smaller streams can cool rapidly below riparian gaps. Temperature increases within gaps were similarly variable. Akaike Information Criteria (AIC) is applied to candidate model variable sets for explaining within-gap temperature sensitivity and downstream cooling rates. Understanding downstream cooling is critical for the development of riparian management policies for cold-water species.

  18. Approximating subtree distances between phylogenies.

    PubMed

    Bonet, Maria Luisa; St John, Katherine; Mahindru, Ruchi; Amenta, Nina

    2006-10-01

    We give a 5-approximation algorithm to the rooted Subtree-Prune-and-Regraft (rSPR) distance between two phylogenies, which was recently shown to be NP-complete. This paper presents the first approximation result for this important tree distance. The algorithm follows a standard format for tree distances. The novel ideas are in the analysis. In the analysis, the cost of the algorithm uses a "cascading" scheme that accounts for possible wrong moves. This accounting is missing from previous analysis of tree distance approximation algorithms. Further, we show how all algorithms of this type can be implemented in linear time and give experimental results.

  19. Trade-off between competition and facilitation defines gap colonization in mountains

    PubMed Central

    Lembrechts, Jonas J.; Milbau, Ann; Nijs, Ivan

    2015-01-01

    Recent experimental observations show that gap colonization in small-stature (e.g. grassland and dwarf shrubs) vegetation strongly depends on the abiotic conditions within them. At the same time, within-gap variation in biotic interactions such as competition and facilitation, caused by distance to the gap edge, would affect colonizer performance, but a theoretical framework to explore such patterns is missing. Here, we model how competition, facilitation and environmental conditions together determine the small-scale patterns of gap colonization along a cold gradient in mountains, by simulating colonizer survival in gaps of various sizes. Our model adds another dimension to the known effects of biotic interactions along a stress gradient by focussing on the trade-off between competition and facilitation in the within-gap environment. We show that this trade-off defines a peak in colonizer survival at a specific distance from the gap edge, which progressively shifts closer to the edge as the environment gets colder, ultimately leaving a large fraction of gaps unsuitable for colonization in facilitation-dominated systems. This is reinforced when vegetation size and temperature amelioration are manipulated simultaneously with temperature in order to simulate an elevational gradient more realistically. Interestingly, all other conditions being equal, the magnitude of the realized survival peak was always lower in large than in small gaps, making large gaps harder to colonize. The model is relevant to predict effects of non-native plant invasions and climate warming on colonization processes in mountains. PMID:26558706

  20. Transactional Distance and Autonomy in a Distance Learning Environment

    ERIC Educational Resources Information Center

    Vasiloudis, G.; Koutsouba, M.; Giossos, Y.; Mavroidis, I.

    2015-01-01

    This paper studies the transactional distance between the students and the tutor as well as the autonomy of students in a postgraduate course of the Hellenic Open University (HOU). The aim of the paper is to examine how the relation between autonomy and transactional distance evolves during an academic year and how this relation is affected by…

  1. Policy Deficit in Distance Education: A Transactional Distance

    ERIC Educational Resources Information Center

    Gokool-Ramdoo, Sushita

    2009-01-01

    This paper innovatively extends the application of transactional distance theory (TDT) to evidence-based policy development in Mauritius. In-depth interview data on student persistence from a range of stakeholders is used to understand the implications of distance education (DE) policy deficit. Policy deficit has surfaced as another dimension of…

  2. Transactional Distance and Autonomy in a Distance Learning Environment

    ERIC Educational Resources Information Center

    Vasiloudis, G.; Koutsouba, M.; Giossos, Y.; Mavroidis, I.

    2015-01-01

    This paper studies the transactional distance between the students and the tutor as well as the autonomy of students in a postgraduate course of the Hellenic Open University (HOU). The aim of the paper is to examine how the relation between autonomy and transactional distance evolves during an academic year and how this relation is affected by…

  3. Lifelong Learning & Distance Higher Education. Perspectives on Distance Education

    ERIC Educational Resources Information Center

    McIntosh, Christopher, Ed.

    2005-01-01

    Reflecting a common objective of ensuring quality Education for All, this book is a joint initiative of UNESCO and COL and jointly published. Lifelong Learning in Distance Higher Education brings together a diverse group of experts from many countries. The book provides a clear picture of the challenges, problems and potential of distance higher…

  4. Non-uniformity effects of the inter-foil distance on GEM detector performance

    NASA Astrophysics Data System (ADS)

    Huang,Yan; Yi, Han; Xiao, Zhi-Gang; Zhang, Zhao; Cheng, Wen-Jing; Lü, Li-Ming; Yan, Wei-Hua; Wang, Ren-Sheng; Li, Hong-Jie; Zhang, Yan; Duan, Li-Min; Hu, Rong-Jiang; Lu, Chen-Gui; Yang, He-Run; Ma, Peng; Gao, Hai-Yan

    2016-04-01

    The non-uniformity effect of the inter-foil distance has been studied using a gaseous electron multiplication (GEM) detector with sensitive area of 50mm × 50mm. A gradient of the inter-foil distance is introduced by using spacers with different heights at the two ends of the foil gap. While the cluster size and the intrinsic spatial resolution show insignificant dependence on the inter-foil distance, the gain exhibits an approximately linear dependence on the inter-foil distance. From the slope, a quantitative relationship between the change of the inter-foil distance and the change of the gain is derived, which can be used as a method to evaluate the non-uniformity of the foil gap in the application of large-area GEM detectors. Supported by National Natural Science Foundation of China (11375094, U1332207, 11120101004), and by Tsinghua University Initiative Scientific Research Program

  5. Preionization Techniques in a kJ-Scale Dense Plasma Focus

    NASA Astrophysics Data System (ADS)

    Povilus, Alexander; Shaw, Brian; Chapman, Steve; Podpaly, Yuri; Cooper, Christopher; Falabella, Steve; Prasad, Rahul; Schmidt, Andrea

    2016-10-01

    A dense plasma focus (DPF) is a type of z-pinch device that uses a high current, coaxial plasma gun with an implosion phase to generate dense plasmas. These devices can accelerate a beam of ions to MeV-scale energies through strong electric fields generated by instabilities during the implosion of the plasma sheath. The formation of these instabilities, however, relies strongly on the history of the plasma sheath in the device, including the evolution of the gas breakdown in the device. In an effort to reduce variability in the performance of the device, we attempt to control the initial gas breakdown in the device by seeding the system with free charges before the main power pulse arrives. We report on the effectiveness of two techniques developed for a kJ-scale DPF at LLNL, a miniature primer spark gap and pulsed, 255nm LED illumination. Prepared by LLNL under Contract DE-AC52-07NA27344.

  6. Axial gap rotating electrical machine

    DOEpatents

    None

    2016-02-23

    Direct drive rotating electrical machines with axial air gaps are disclosed. In these machines, a rotor ring and stator ring define an axial air gap between them. Sets of gap-maintaining rolling supports bear between the rotor ring and the stator ring at their peripheries to maintain the axial air gap. Also disclosed are wind turbines using these generators, and structures and methods for mounting direct drive rotating electrical generators to the hubs of wind turbines. In particular, the rotor ring of the generator may be carried directly by the hub of a wind turbine to rotate relative to a shaft without being mounted directly to the shaft.

  7. Gap and stripline combined monitor

    DOEpatents

    Yin, Y.

    1984-02-16

    A combined gap and stripline monitor device for measuring the intensity and position of a charged particle beam bunch in a beam pipe of a synchrotron radiation facility. The monitor has first and second beam pipe portions with an axial gap therebetween. An outer pipe cooperates with the first beam pipe portion to form a gap enclosure, while inner strips cooperate with the first beam pipe portion to form a stripline monitor, with the stripline length being the same as the gap enclosure length.

  8. Gap and stripline combined monitor

    DOEpatents

    Yin, Y.

    1986-08-19

    A combined gap and stripline monitor device for measuring the intensity and position of a charged particle beam bunch in a beam pipe of a synchrotron radiation facility is disclosed. The monitor has first and second beam pipe portions with an axial gap therebetween. An outer pipe cooperates with the first beam pipe portion to form a gap enclosure, while inner strips cooperate with the first beam pipe portion to form a stripline monitor, with the stripline length being the same as the gap enclosure length. 4 figs.

  9. Gap and stripline combined monitor

    DOEpatents

    Yin, Yan

    1986-01-01

    A combined gap and stripline monitor device (10) for measuring the intensity and position of a charged particle beam bunch in a beam pipe of a synchotron radiation facility. The monitor has first and second beam pipe portions (11a, 11b) with an axial gap (12) therebetween. An outer pipe (14) cooperates with the first beam pipe portion (11a) to form a gap enclosure, while inner strips (23a-d) cooperate with the first beam pipe portion (11a) to form a stripline monitor, with the stripline length being the same as the gap enclosure length.

  10. Shock wave propagation past a gap in a pipeline

    NASA Astrophysics Data System (ADS)

    Hall, Russell; Kapfudzaruwa, Simbarashe; Skews, Beric; Paton, Randall

    2017-08-01

    This study numerically and experimentally examines the resulting flow field of a shock wave passing through a pipe gap. The effects of gap geometry and shock Mach number variation are investigated. Incident shock Mach numbers of 1.3, 1.4, and 1.5 and gap widths of 25 and 50 mm were used, which correspond to 0.5 and 1.0 pipe inner diameters, respectively. For both cases, the incident shock wave propagated into the downstream pipe at much reduced strength. A strong expansion propagated into the upstream pipe causing a significant pressure drop from the initial post-shock pressure. Expansion waves at the outflow resulted in supersonic speeds as the flow entered the gap for Mach 1.4 and 1.5. A notable feature was the formation of a standing shock at the inlet to the downstream pipe for the higher two Mach numbers in both cases. Decreasing the gap width moved the standing shock closer to the downstream pipe. For the lowest Mach number of 1.3, no standing shock system was set up. The propagation conditions in the downstream pipe showed that the pressure is initially unsteady, but becomes more uniform, controlled by the developed wave system in the gap. For the flanged gap case, the flow within the gap is confined for much longer and hence produces more intense and complex flow feature interactions and an earlier transition to turbulence. The induced shock strength in the downstream pipe is independent of gap geometry and separation distance examined in this paper as verified by experimental pressure traces.

  11. Directory of Distance Education Professionals.

    ERIC Educational Resources Information Center

    Bhushan, Bharat, Ed.; Rausaria, R. R., Ed.

    This directory of distance education professionals in India covers personnel working in open universities, correspondence course institutes, and directorates of distance education of conventional universities and other national level research institutes. The information was derived from a set of structured questionnaires sent to all involved…

  12. Interactive Television and Distance Learning.

    ERIC Educational Resources Information Center

    Rees, Fred J.; Downs, Dennis A.

    1995-01-01

    Describes the origins and operations of the Iowa Communications Network, an interactive distance learning program. Presents several examples of how the network can benefit music educators in college and K-12 institutions. Maintains that the system can be a model for similar distance music education networks. (CFR)

  13. Blogging for the Distance Librarian

    ERIC Educational Resources Information Center

    Pival, Paul R.

    2005-01-01

    Based on user lookups, "Merriam-Webster Online "proclaimed "Blog" the word of the year for 2004. Distance librarianship, until mid-way through 2004, was a subject that was underrepresented in the blogosphere. The inception of a blog called "The Distant Librarian: Comments on the World of Distance Librarianship" is chronicled in this article, along…

  14. The Distance to M104

    NASA Astrophysics Data System (ADS)

    McQuinn, Kristen. B. W.; Skillman, Evan D.; Dolphin, Andrew E.; Berg, Danielle; Kennicutt, Robert

    2016-11-01

    M104 (NGC 4594; the Sombrero galaxy) is a nearby, well-studied elliptical galaxy included in scores of surveys focused on understanding the details of galaxy evolution. Despite the importance of observations of M104, a consensus distance has not yet been established. Here, we use newly obtained Hubble Space Telescope optical imaging to measure the distance to M104 based on the tip of the red giant branch (TRGB) method. Our measurement yields the distance to M104 to be 9.55 ± 0.13 ± 0.31 Mpc equivalent to a distance modulus of 29.90 ± 0.03 ± 0.07 mag. Our distance is an improvement over previous results as we use a well-calibrated, stable distance indicator, precision photometry in a optimally selected field of view, and a Bayesian maximum likelihood technique that reduces measurement uncertainties. The most discrepant previous results are due to Tully-Fisher method distances, which are likely inappropriate for M104 given its peculiar morphology and structure. Our results are part of a larger program to measure accurate distances to a sample of well-known spiral galaxies (including M51, M74, and M63) using the TRGB method. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the Data Archive at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.

  15. Distance Education and Developing Countries.

    ERIC Educational Resources Information Center

    Daniel, John S.

    The purpose of this paper is to give those who work in distance education a better awareness of the factors at work in developing nations and to help those whose profession is national development gain a fuller understanding of distance education. It begins with a discussion of the process of national development which focuses on the factors that…

  16. Quality Content in Distance Education

    ERIC Educational Resources Information Center

    Yildiz, Ezgi Pelin; Isman, Aytekin

    2016-01-01

    In parallel with technological advances in today's world of education activities can be conducted without the constraints of time and space. One of the most important of these activities is distance education. The success of the distance education is possible with content quality. The proliferation of e-learning environment has brought a need for…

  17. Distance Educator: A Multiskill Personality

    ERIC Educational Resources Information Center

    Malik, Sangeeta

    2013-01-01

    When we talk about a distance educator and a conventional educator the difference we found about both of them is that a distance educator needs to play multiple roles as compared to a conventional educator. They require more skills and knowledge to cater to the needs of the learner. In this article we will cover all the responsible areas of a…

  18. Virtual Bioinformatics Distance Learning Suite

    ERIC Educational Resources Information Center

    Tolvanen, Martti; Vihinen, Mauno

    2004-01-01

    Distance learning as a computer-aided concept allows students to take courses from anywhere at any time. In bioinformatics, computers are needed to collect, store, process, and analyze massive amounts of biological and biomedical data. We have applied the concept of distance learning in virtual bioinformatics to provide university course material…

  19. USAF Initiatives in Distance Learning.

    ERIC Educational Resources Information Center

    Wolfe, Thomas E.

    1996-01-01

    Examines the expansive growth of distance learning in the United States Air Force (USAF). Highlights include interactive television and the Air Technology Network that uses satellites; computer-based instruction; online electronic campus; multimedia interactive courseware; CD-ROM; distance learning benefits; data collection; administration; and…

  20. Distance Learning: The Essential Guide.

    ERIC Educational Resources Information Center

    Williams, Marcia L.; Paprock, Kenneth; Covington, Barbara

    Intended for individuals engaged in open and distance learning activities, this guide is designed with an applications focus that provides a "quick start" for immediate work needs. Built on an intuitive set of "How do I" questions, the book presents the foundation needed to teach from a distance. The format is a multimodel approach, combining…

  1. The Distance to M51

    NASA Astrophysics Data System (ADS)

    McQuinn, Kristen. B. W.; Skillman, Evan D.; Dolphin, Andrew E.; Berg, Danielle; Kennicutt, Robert

    2016-07-01

    Great investments of observing time have been dedicated to the study of nearby spiral galaxies with diverse goals ranging from understanding the star formation process to characterizing their dark matter distributions. Accurate distances are fundamental to interpreting observations of these galaxies, yet many of the best studied nearby galaxies have distances based on methods with relatively large uncertainties. We have started a program to derive accurate distances to these galaxies. Here we measure the distance to M51—the Whirlpool galaxy—from newly obtained Hubble Space Telescope optical imaging using the tip of the red giant branch method. We measure the distance modulus to be 8.58 ± 0.10 Mpc (statistical), corresponding to a distance modulus of 29.67 ± 0.02 mag. Our distance is an improvement over previous results as we use a well-calibrated, stable distance indicator, precision photometry in a optimally selected field of view, and a Bayesian Maximum Likelihood technique that reduces measurement uncertainties. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the Data Archive at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.

  2. Distance Learning: Practice and Dilemmas

    ERIC Educational Resources Information Center

    Tatkovic, Nevenka; Sehanovic, Jusuf; Ruzic, Maja

    2006-01-01

    In accordance with the European processes of integrated and homogeneous education, the paper presents the essential viewpoints and questions covering the establishment and development of "distance learning" (DL) in Republic of Croatia. It starts from the advantages of distance learning versus traditional education taking into account…

  3. USAF Initiatives in Distance Learning.

    ERIC Educational Resources Information Center

    Wolfe, Thomas E.

    1996-01-01

    Examines the expansive growth of distance learning in the United States Air Force (USAF). Highlights include interactive television and the Air Technology Network that uses satellites; computer-based instruction; online electronic campus; multimedia interactive courseware; CD-ROM; distance learning benefits; data collection; administration; and…

  4. Distance Education: Educational Trajectory Control

    ERIC Educational Resources Information Center

    Isaev, Andrey; Kravets, Alla; Isaeva, Ludmila; Fomenkov, Sergey

    2013-01-01

    Distance education has become a rather popular form of education recently. The advantages of this form are obvious and well-known. They include asynchronous learning, individualized learning trajectories and convenient case technologies. However, the distance form of education is not able to form the trainee's hands-on experience, especially…

  5. Examining Distance Education in Turkey.

    ERIC Educational Resources Information Center

    McIsaac, Marina Stock; And Others

    1988-01-01

    Describes the distance education program at Anadolu University in Turkey and compares its problems and solutions with similar distance programs in other Asian countries. A brief history is presented, enrollment figures are given, and future directions are described. (Author/LRW)

  6. Distance Education in Rural Areas.

    ERIC Educational Resources Information Center

    Zucker, Henry

    This discussion of social and political aspects, advantages and disadvantages of distance education programs includes descriptions and examples of delivery technologies and programs in developing and developed countries. Among the social aspects considered are distance education's potential to provide a second chance to people who are trapped by…

  7. Is Distance Education for You?

    ERIC Educational Resources Information Center

    Walter, Laura M.

    2004-01-01

    Millions of Americans are currently enrolled in distance learning institutions. The flexible study schedules, independent learning, and self-paced courses are attracting more students than ever. Those interested in enrolling in a distance education school, probably have a lot of questions. Choosing the right school is an important decision, and…

  8. Distance Education: A Cost Analysis.

    ERIC Educational Resources Information Center

    Jones, Judy I.; Simonson, Michael

    The costs of three types of transmission technology in distance education are compared, and the costs for equipping and installing a distance education classroom are estimated. Two of the technologies--fiber optics and microwave--deliver two-way, full motion video and two-way audio. The third technology, compressed video, also delivers two-way…

  9. Adult Education at a Distance.

    ERIC Educational Resources Information Center

    Gaudet, Alphonse

    This document, which examines the use of educational technologies for distance education for adults in Canada, consists of five narrative sections and a bibliography. The first section introduces the topic and the document's objectives (to describe those technologies used in Canadian adult distance education, paying particular attention to those…

  10. Multimedia Equipment for Distance Education.

    ERIC Educational Resources Information Center

    Schiller, Scott S.

    1993-01-01

    Discusses the use of multimedia equipment for distance education. Topics addressed include use of the Internet; distance learning for educators; and cable television and/or fiber optics, including interactive television and satellite technology. A sidebar lists online and telecommunications providers. (LRW)

  11. Faculty Attitudes about Distance Education

    ERIC Educational Resources Information Center

    Smidt, Esther; McDyre, Brian; Bunk, Jennifer; Li, Rui; Gatenby, Tanya

    2014-01-01

    In recent years, there has been a dramatic increase in distance learning in higher education. Given this, it is extremely important to understand faculty attitudes about distance education, not only because they can vary widely, but also because it is the faculty, through their design and implementation of online courses, that will shape the…

  12. Virtual Bioinformatics Distance Learning Suite

    ERIC Educational Resources Information Center

    Tolvanen, Martti; Vihinen, Mauno

    2004-01-01

    Distance learning as a computer-aided concept allows students to take courses from anywhere at any time. In bioinformatics, computers are needed to collect, store, process, and analyze massive amounts of biological and biomedical data. We have applied the concept of distance learning in virtual bioinformatics to provide university course material…

  13. Distance Education for Continuing Education.

    ERIC Educational Resources Information Center

    Sharma, Motilal

    The role of distance education as a vehicle for delivering continuing education in Asia was examined from the following standpoints: facilitating development amidst poverty; making human resource development the prime strategy; overcoming the stagnation of education amidst wrenching change; and using distance education to accomplish those…

  14. Distance Education. [SITE 2001 Section].

    ERIC Educational Resources Information Center

    Fuller, Frank, Ed.; McBride, Ron, Ed.

    This document contains the papers on distance education from the SITE (Society for Information Technology & Teacher Education) 2001 conference. Topics covered include: the distance education degree program for the Master of Mathematics with a teaching option at Texas A&M University; the evolution of online learning; Internet-based distance…

  15. Hierarchical traits distances explain grassland Fabaceae species' ecological niches distances

    PubMed Central

    Fort, Florian; Jouany, Claire; Cruz, Pablo

    2015-01-01

    Fabaceae species play a key role in ecosystem functioning through their capacity to fix atmospheric nitrogen via their symbiosis with Rhizobium bacteria. To increase benefits of using Fabaceae in agricultural systems, it is necessary to find ways to evaluate species or genotypes having potential adaptations to sub-optimal growth conditions. We evaluated the relevance of phylogenetic distance, absolute trait distance and hierarchical trait distance for comparing the adaptation of 13 grassland Fabaceae species to different habitats, i.e., ecological niches. We measured a wide range of functional traits (root traits, leaf traits, and whole plant traits) in these species. Species phylogenetic and ecological distances were assessed from a species-level phylogenetic tree and species' ecological indicator values, respectively. We demonstrated that differences in ecological niches between grassland Fabaceae species were related more to their hierarchical trait distances than to their phylogenetic distances. We showed that grassland Fabaceae functional traits tend to converge among species with the same ecological requirements. Species with acquisitive root strategies (thin roots, shallow root systems) are competitive species adapted to non-stressful meadows, while conservative ones (coarse roots, deep root systems) are able to tolerate stressful continental climates. In contrast, acquisitive species appeared to be able to tolerate low soil-P availability, while conservative ones need high P availability. Finally we highlight that traits converge along the ecological gradient, providing the assumption that species with similar root-trait values are better able to coexist, regardless of their phylogenetic distance. PMID:25741353

  16. Reducing the distance in distance-caregiving by technology innovation

    PubMed Central

    Benefield, Lazelle E; Beck, Cornelia

    2007-01-01

    Family caregivers are responsible for the home care of over 34 million older adults in the United States. For many, the elder family member lives more than an hour’s distance away. Distance caregiving is a growing alternative to more familiar models where: 1) the elder and the family caregiver(s) may reside in the same household; or 2) the family caregiver may live nearby but not in the same household as the elder. The distance caregiving model involves elders and their family caregivers who live at some distance, defined as more than a 60-minute commute, from one another. Evidence suggests that distance caregiving is a distinct phenomenon, differs substantially from on-site family caregiving, and requires additional assistance to support the physical, social, and contextual dimensions of the caregiving process. Technology-based assists could virtually connect the caregiver and elder and provide strong support that addresses the elder’s physical, social, cognitive, and/or sensory impairments. Therefore, in today’s era of high technology, it is surprising that so few affordable innovations are being marketed for distance caregiving. This article addresses distance caregiving, proposes the use of technology innovation to support caregiving, and suggests a research agenda to better inform policy decisions related to the unique needs of this situation. PMID:18044143

  17. The art of descrying distance.

    PubMed

    Niall, K K

    1999-09-01

    How naive can one experiment be? Imagine asking observers to judge distance -- yes, literally asking them. And in asking them, no visual evoked potentials were measured, and changes in blood flow to the occipital cortex were ignored. But serendipity occurs even to the well-prepared: One's best thought for a new experiment can prove to be one's first unbiased, uncomplicated thought.Here's a cursory review of the events: A number of observers were asked to judge distances between marked posts in a field at night. They made their judgments with the help of night vision goggles (NVG). At first the observers underestimated the distances on average. Then an experimenter began to correct the observers after each judgment. The observers' judgments of distance became accurate. On average, the observers began to estimate those distances accurately. Is this and incredible story or a difficult one?

  18. Application of Terahertz Time-Domain Spectroscopy in Detecting Gaps with Different Widths.

    PubMed

    Bao, Rima; Wu, Zhikui; Wang, Fang; Miao, Xinyang; Feng, Chengjing

    2017-01-01

    The characterization of fractures is of vital importance for studies in many industries. In the present work, we used terahertz reflection measurements to identify simulated gaps of different widths that resemble fractures. The time interval between pulses (Δt) was proportional to the distance between the interfaces. In addition, fast Fourier transform (FFT) corresponding to the waveforms was also employed to distinguish the gaps. The widths in frequency were found to be inversely proportional to that of the gaps. In general, both terahertz time-domain spectroscopy (THz-TDS) and terahertz frequency-domain spectroscopy (THz-FDS) can achieve the measurement of the gaps of micro size.

  19. fastGapFill: efficient gap filling in metabolic networks

    PubMed Central

    Thiele, Ines; Vlassis, Nikos; Fleming, Ronan M. T.

    2014-01-01

    Motivation: Genome-scale metabolic reconstructions summarize current knowledge about a target organism in a structured manner and as such highlight missing information. Such gaps can be filled algorithmically. Scalability limitations of available algorithms for gap filling hinder their application to compartmentalized reconstructions. Results: We present fastGapFill, a computationally efficient tractable extension to the COBRA toolbox that permits the identification of candidate missing knowledge from a universal biochemical reaction database (e.g. Kyoto Encyclopedia of Genes and Genomes) for a given (compartmentalized) metabolic reconstruction. The stoichiometric consistency of the universal reaction database and of the metabolic reconstruction can be tested for permitting the computation of biologically more relevant solutions. We demonstrate the efficiency and scalability of fastGapFill on a range of metabolic reconstructions. Availability and implementation: fastGapFill is freely available from http://thielelab.eu. Contact: ines.thiele@uni.lu Supplementary information: Supplementary data are available at Bioinformatics online. PMID:24812336

  20. A K-12 Written Guidance Plan. Minimum Standards Implementation Series.

    ERIC Educational Resources Information Center

    Ohio State Dept. of Education, Columbus. Div. of Elementary and Secondary Education.

    One of a series of implementation documents prepared in conjunction with the revised minimum standards adopted in 1983 by the Ohio State Board of Education for elementary and secondary schools, this leadership document addresses the need, the purpose, and the implementation procedures for a K-12 written guidance plan in accordance with the Ohio…

  1. Gifted Education and National Standards: A K-5 Program Evaluation

    ERIC Educational Resources Information Center

    Harwell-Braun, Debra A.

    2010-01-01

    The purpose of this study was to conduct a program evaluation of a K-5 Gifted Education Program. Program evaluation addressed how well the gifted education program studied met the National Association of Gifted Children standards. In addition, this study included stakeholder perceptions of the current gifted education program K-5. This program…

  2. Genealogical trees from genetic distances

    NASA Astrophysics Data System (ADS)

    Prignano, L.; Serva, M.

    2009-06-01

    In a population with haploid reproduction any individual has a single parent in the previous generation. If all genealogical distances among pairs of individuals (generations from the closest common ancestor) are known it is possible to exactly reconstruct their genealogical tree. Unfortunately, in most cases, genealogical distances are unknown and only genetic distances are available. The genetic distance between two individuals is measurable from differences in mtDNA (mitochondrial DNA) since in the case of humans or other complex organisms mtDNA is transmitted in a haploid manner. An analogous distance can be also computed for languages where it may be measured from lexical differences, in this case, nevertheless, haploid reproduction is only a raw approximation. Assuming a constant rate of mutation, these genetic distances are random and proportional only on average to genealogical ones. The reconstruction of the genealogical tree from the available genetic distances is forceful imprecise. In this paper we try to quantify the error one may commit in the reconstruction of the tree for different degrees of randomness. The errors may concern both topology of the tree (the branching hierarchy) and, in case of correct topology, the proportions of the tree (length of various branches).

  3. Measuring the Gap

    PubMed Central

    She, Xinshu; Zhao, Deqing; Scholnick, Jenna

    2016-01-01

    China is a large country where rapid development is accompanied by growing inequalities. How economic inequalities translate to health inequalities is unknown. Baseline health assessment is lacking among rural Chinese children. We aimed at assessing baseline student health of rural Chinese children and comparing them with those of urban children of similar ages. A cross-sectional study was conducted using the 2003 Global School-Based Student Health Survey among 100 students Grade 4 to 6 from rural Guizhou, China. Results were summarized and compared with public data from urban Beijing using multivariate logistic regression models. Rural children are more likely to not wash their hands before a meal (odds ratio [OR] = 5.71, P < .01) and after using the toilet (OR = 5.41, P < .01). They are more likely to feel sick or to get into trouble after drinking (OR = 7.28, P < .01). They are more likely to have used drugs (OR = 8.54, P < .01) and to have no close friends (OR = 8.23, P < .01). An alarming percentage of rural (8.22%) and urban (14.22%) children have had suicidal ideation in the past year (OR = 0.68, P > .05). Rural parents are more likely to not know their children’s whereabouts (OR = 1.81, P < .05). Rural children are more than 4 times likely to have serious injuries (OR = 4.64, P < .01) and to be bullied (OR = 4.01, P < .01). In conclusion, school-age rural Chinese children exhibit more health risk behaviors and fewer protective factors at baseline compared to their urban counterparts. Any intervention aimed at improving child health should take this distributive gap into consideration. PMID:27335999

  4. Language distance and tree reconstruction

    NASA Astrophysics Data System (ADS)

    Petroni, Filippo; Serva, Maurizio

    2008-08-01

    Languages evolve over time according to a process in which reproduction, mutation and extinction are all possible. This is very similar to haploid evolution for asexual organisms and for the mitochondrial DNA of complex ones. Exploiting this similarity, it is possible, in principle, to verify hypotheses concerning the relationship among languages and to reconstruct their family tree. The key point is the definition of the distances among pairs of languages in analogy with the genetic distances among pairs of organisms. Distances can be evaluated by comparing grammar and/or vocabulary, but while it is difficult, if not impossible, to quantify grammar distance, it is possible to measure a distance from vocabulary differences. The method used by glottochronology computes distances from the percentage of shared 'cognates', which are words with a common historical origin. The weak point of this method is that subjective judgment plays a significant role. Here we define the distance of two languages by considering a renormalized edit distance among words with the same meaning and averaging over the two hundred words contained in a Swadesh list. In our approach the vocabulary of a language is the analogue of DNA for organisms. The advantage is that we avoid subjectivity and, furthermore, reproducibility of results is guaranteed. We apply our method to the Indo-European and the Austronesian groups, considering, in both cases, fifty different languages. The two trees obtained are, in many respects, similar to those found by glottochronologists, with some important differences as regards the positions of a few languages. In order to support these different results we separately analyze the structure of the distances of these languages with respect to all the others.

  5. Mapping forest canopy gaps using air-photo interpretation and ground surveys

    USGS Publications Warehouse

    Fox, T.J.; Knutson, M.G.; Hines, R.K.

    2000-01-01

    Canopy gaps are important structural components of forested habitats for many wildlife species. Recent improvements in the spatial accuracy of geographic information system tools facilitate accurate mapping of small canopy features such as gaps. We compared canopy-gap maps generated using ground survey methods with those derived from air-photo interpretation. We found that maps created from high-resolution air photos were more accurate than those created from ground surveys. Errors of omission were 25.6% for the ground-survey method and 4.7% for the air-photo method. One variable of inter est in songbird research is the distance from nests to gap edges. Distances from real and simulated nests to gap edges were longer using the ground-survey maps versus the air-photo maps, indicating that gap omission could potentially bias the assessment of spatial relationships. If research or management goals require location and size of canopy gaps and specific information about vegetation structure, we recommend a 2-fold approach. First, canopy gaps can be located and the perimeters defined using 1:15,000-scale or larger aerial photographs and the methods we describe. Mapped gaps can then be field-surveyed to obtain detailed vegetation data.

  6. GAP Analysis Bulletin Number 15

    USGS Publications Warehouse

    Maxwell, Jill; Gergely, Kevin; Aycrigg, Jocelyn; Canonico, Gabrielle; Davidson, Anne; Coffey, Nicole

    2008-01-01

    The Mission of the Gap Analysis Program (GAP) is to promote conservation by providing broad geographic information on biological diversity to resource managers, planners, and policy makers who can use the information to make informed decisions. As part of the National Biological Information Infrastructure (NBII) ?a collaborative program to provide increased access to data and information on the nation?s biological resources--GAP data and analytical tools have been used in hundreds of applications: from basic research to comprehensive state wildlife plans; from educational projects in schools to ecoregional assessments of biodiversity. The challenge: keeping common species common means protecting them BEFORE they become threatened. To do this on a state or regional basis requires key information such as land cover descriptions, predicted distribution maps for native animals, and an assessment of the level of protection currently given to those plants and animals. GAP works cooperatively with Federal, state, and local natural resource professionals and academics to provide this kind of information. GAP activities focus on the creation of state and regional databases and maps that depict patterns of land management, land cover, and biodiversity. These data can be used to identify ?gaps? in conservation--instances where an animal or plant community is not adequately represented on the existing network of conservation lands. GAP is administered through the U.S. Geological Survey. Through building partnerships among disparate groups, GAP hopes to foster the kind of collaboration that is needed to address conservation issues on a broad scale. For more information, contact: John Mosesso National GAP Director 703-648-4079 Kevin Gergely National GAP Operations Manager 208-885-3565

  7. 76 FR 60452 - In the Matter of: Bahram Maghazehe, a.k.a. Benjamin Maghazehe, a.k.a. Ben Maghazehe, 154 Sequoia...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-29

    ... Bureau of Industry and Security In the Matter of: Bahram Maghazehe, a.k.a. Benjamin Maghazehe, a.k.a. Ben Maghazehe, 154 Sequoia Drive, Newtown, PA 18940, Respondent; Order Relating to Bahram Maghazehe a.k.a. Benjamin Maghazehe a.k.a. Ben Maghazehe The Bureau of Industry and Security, U.S. Department of Commerce...

  8. Discrimination of outer membrane proteins using a K-nearest neighbor method.

    PubMed

    Yan, C; Hu, J; Wang, Y

    2008-06-01

    Identification of outer membrane proteins (OMPs) from genome is an important task. This paper presents a k-nearest neighbor (K-NN) method for discriminating outer membrane proteins (OMPs). The method makes predictions based on a weighted Euclidean distance that is computed from residue composition. The method achieves 89.1% accuracy with 0.668 MCC (Matthews correlation coefficient) in discriminating OMPs and non-OMPs. The performance of the method is improved by including homologous information into the calculation of residue composition. The final method achieves an accuracy of 96.1%, with 0.873 MCC, 87.5% sensitivity, and 98.2% specificity. Comparisons with multiple recently published methods show that the method proposed in this study outperforms the others.

  9. Propagation and localization of quantum dot emission along a gap-plasmonic transmission line.

    PubMed

    Castro-Lopez, M; Manjavacas, A; García de Abajo, J; van Hulst, N F

    2015-11-16

    Plasmonic transmission lines have great potential to serve as direct interconnects between nanoscale light spots. The guiding of gap plasmons in the slot between adjacent nanowire pairs provides improved propagation of surface plasmon polaritons while keeping strong light confinement. Yet propagation is fundamentally limited by losses in the metal. Here we show a workaround operation of the gap-plasmon transmission line, exploiting both gap and external modes present in the structure. Interference between these modes allows us to take advantage of the larger propagation distance of the external mode while preserving the high confinement of the gap mode, resulting in nanoscale confinement of the optical field over a longer distance. The performance of the gap-plasmon transmission line is probed experimentally by recording the propagation of quantum dots luminescence over distances of more than 4 μm. We observe a 35% increase in the effective propagation length of this multimode system compared to the theoretical limit for a pure gap mode. The applicability of this simple method to nanofabricated structures is theoretically confirmed and offers a realistic way to combine longer propagation distances with lateral plasmon confinement for far field nanoscale interconnects.

  10. DISK-SATELLITE INTERACTION IN DISKS WITH DENSITY GAPS

    SciTech Connect

    Petrovich, Cristobal; Rafikov, Roman R.

    2012-10-10

    Gravitational coupling between a gaseous disk and an orbiting perturber leads to angular momentum exchange between them that can result in gap opening by planets in protoplanetary disks and clearing of gas by binary supermassive black holes (SMBHs) embedded in accretion disks. Understanding the co-evolution of the disk and the orbit of the perturber in these circumstances requires knowledge of the spatial distribution of the torque exerted by the latter on a highly non-uniform disk. Here we explore disk-satellite interaction in disks with gaps in linear approximation both in Fourier and in physical space, explicitly incorporating the disk non-uniformity in the fluid equations. Density gradients strongly displace the positions of Lindblad resonances in the disk (which often occur at multiple locations), and the waveforms of modes excited close to the gap edge get modified compared to the uniform disk case. The spatial distribution of the excitation torque density is found to be quite different from the existing prescriptions: most of the torque is exerted in a rather narrow region near the gap edge where Lindblad resonances accumulate, followed by an exponential falloff with the distance from the perturber. Despite these differences, for a given gap profile, the full integrated torque exerted on the disk agrees with the conventional uniform disk theory prediction at the level of {approx}10%. The nonlinearity of the density wave excited by the perturber is shown to decrease as the wave travels out of the gap, slowing down its nonlinear evolution and damping. Our results suggest that gap opening in protoplanetary disks and gas clearing around SMBH binaries can be more efficient than the existing theories predict. They pave the way for self-consistent calculations of the gap structure and the orbital evolution of the perturber using accurate prescription for the torque density behavior.

  11. GAPS IN PROTOPLANETARY DISKS AS SIGNATURES OF PLANETS. I. METHODOLOGY AND VALIDATION

    SciTech Connect

    Jang-Condell, Hannah; Turner, Neal J.

    2012-04-20

    We examine the observational consequences of partial gaps being opened by planets in protoplanetary disks. We model the disk using a static {alpha}-disk model with detailed radiative transfer, parameterizing the shape and size of the partially cleared gaps based on the results of hydrodynamic simulations. Shadowing and illumination by stellar irradiation at the surface of the gap leads to increased contrast as the gap trough is deepened by shadowing and cooling and the far gap wall is puffed up by illumination and heating. In calculating observables, we find that multiple scattering is important and derive an approximation to include these effects. A gap produced by a 200 M{sub Circled-Plus} (70 M{sub Circled-Plus }) planet at 10 AU can lower/raise the midplane temperature of the disk by up to {approx} - 25%/+29% ({approx} - 11/+ 19) by shadowing in the gap trough and illumination on the far shoulder of the gap. At the distance of Taurus, this gap would be resolvable with {approx}0.''01 angular resolution. The gap contrast is most significant in scattered light and at thermal continuum wavelengths characteristic of the surface temperature, reducing or raising the surface brightness by up to order of magnitude. Since gap sizes are correlated with planet mass, this is a promising way of finding and determining the masses of planets embedded in protoplanetary disks.

  12. Isolation by distance, web service

    PubMed Central

    Jensen, Jeffrey L; Bohonak, Andrew J; Kelley, Scott T

    2005-01-01

    Background The population genetic pattern known as "isolation by distance" results from spatially limited gene flow and is a commonly observed phenomenon in natural populations. However, few software programs exist for estimating the degree of isolation by distance among populations, and they tend not to be user-friendly. Results We have created Isolation by Distance Web Service (IBDWS) a user-friendly web interface for determining patterns of isolation by distance. Using this site, population geneticists can perform a variety of powerful statistical tests including Mantel tests, Reduced Major Axis (RMA) regression analysis, as well as calculate FST between all pairs of populations and perform basic summary statistics (e.g., heterozygosity). All statistical results, including publication-quality scatter plots in Postscript format, are returned rapidly to the user and can be easily downloaded. Conclusion IBDWS population genetics analysis software is hosted at and documentation is available at . The source code has been made available on Source Forge at . PMID:15760479

  13. Advances on Genome Duplication Distances

    NASA Astrophysics Data System (ADS)

    Gagnon, Yves; Savard, Olivier Tremblay; Bertrand, Denis; El-Mabrouk, Nadia

    Given a phylogenetic tree involving Whole Genome Duplication events, we contribute to the problem of computing the rearrangement distance on a branch of a tree linking a duplication node d to a speciation node or a leaf s. In the case of a genome G at s containing exactly two copies of each gene, the genome halving problem is to find a perfectly duplicated genome D at d minimizing the rearrangement distance with G. We generalize the existing exact linear-time algorithm for genome halving to the case of a genome G with missing gene copies. In the case of a known ancestral duplicated genome D, we develop a greedy approach for computing the distance between G and D that is shown time-efficient and very accurate for both the rearrangement and DCJ distances.

  14. Graph distance for complex networks

    NASA Astrophysics Data System (ADS)

    Shimada, Yutaka; Hirata, Yoshito; Ikeguchi, Tohru; Aihara, Kazuyuki

    2016-10-01

    Networks are widely used as a tool for describing diverse real complex systems and have been successfully applied to many fields. The distance between networks is one of the most fundamental concepts for properly classifying real networks, detecting temporal changes in network structures, and effectively predicting their temporal evolution. However, this distance has rarely been discussed in the theory of complex networks. Here, we propose a graph distance between networks based on a Laplacian matrix that reflects the structural and dynamical properties of networked dynamical systems. Our results indicate that the Laplacian-based graph distance effectively quantifies the structural difference between complex networks. We further show that our approach successfully elucidates the temporal properties underlying temporal networks observed in the context of face-to-face human interactions.

  15. Graph distance for complex networks

    PubMed Central

    Shimada, Yutaka; Hirata, Yoshito; Ikeguchi, Tohru; Aihara, Kazuyuki

    2016-01-01

    Networks are widely used as a tool for describing diverse real complex systems and have been successfully applied to many fields. The distance between networks is one of the most fundamental concepts for properly classifying real networks, detecting temporal changes in network structures, and effectively predicting their temporal evolution. However, this distance has rarely been discussed in the theory of complex networks. Here, we propose a graph distance between networks based on a Laplacian matrix that reflects the structural and dynamical properties of networked dynamical systems. Our results indicate that the Laplacian-based graph distance effectively quantifies the structural difference between complex networks. We further show that our approach successfully elucidates the temporal properties underlying temporal networks observed in the context of face-to-face human interactions. PMID:27725690

  16. Distance Learning for Special Populations

    ERIC Educational Resources Information Center

    Bates, Rodger A.

    2012-01-01

    Distance education strategies for remotely deployed, highly mobile, or institutionalized populations are reviewed and critiqued. Specifically, asynchronous, offline responses for special military units, Native Americans on remote reservations, prison populations and other geographically, temporally or technologically isolated niche populations are…

  17. Distance Learning for Special Populations

    ERIC Educational Resources Information Center

    Bates, Rodger A.

    2012-01-01

    Distance education strategies for remotely deployed, highly mobile, or institutionalized populations are reviewed and critiqued. Specifically, asynchronous, offline responses for special military units, Native Americans on remote reservations, prison populations and other geographically, temporally or technologically isolated niche populations are…

  18. Access to myocardial revascularization procedures: Closing the gap with time?

    PubMed Central

    Vanasse, Alain; Niyonsenga, Théophile; Courteau, Josiane; Hemiari, Abbas

    2006-01-01

    Background Early access to revascularization procedures is known to be related to a more favorable outcome in myocardial infarction (MI) patients, but access to specialized care varies widely amongst the population. We aim to test if the early gap found in the revascularization rates, according to distance between patients' location and the closest specialized cardiology center (SCC), remains on a long term basis. Methods We conducted a population-based cohort study using data from the Quebec's hospital discharge register (MED-ECHO). The study population includes all patients 25 years and older living in the province of Quebec, who were hospitalized for a MI in 1999 with a follow up time of one year after the index hospitalization. The main variable is revascularization (percutaneous transluminal coronary angioplasty or a coronary artery bypass graft). The population is divided in four groups depending how close they are from a SCC (<32 km, 32–64 km, 64–105 km and ≥105 km). Revascularization rates are adjusted for age and sex. Results The study population includes 11,802 individuals, 66% are men. The one-year incidence rate of MI is 244 individuals per 100,000 inhabitants. At index hospitalization, a significant gap is found between patients living close (< 32 km) to a SCC and patients living farther (≥32 km). During the first year, a gap reduction can be observed but only for patients living at an intermediate distance from the specialized center (64–105 km). Conclusion The gap observed in revascularization rates at the index hospitalization for MI is in favour of patients living closer (< 32 km) to a SCC. This gap remains unchanged over the first year after an MI except for patients living between 64 and 105 km, where a closing of the gap can be noticed. PMID:16524458

  19. Does a global DNA barcoding gap exist in Annelida?

    PubMed

    Kvist, Sebastian

    2016-05-01

    Accurate identification of unknown specimens by means of DNA barcoding is contingent on the presence of a DNA barcoding gap, among other factors, as its absence may result in dubious specimen identifications - false negatives or positives. Whereas the utility of DNA barcoding would be greatly reduced in the absence of a distinct and sufficiently sized barcoding gap, the limits of intraspecific and interspecific distances are seldom thoroughly inspected across comprehensive sampling. The present study aims to illuminate this aspect of barcoding in a comprehensive manner for the animal phylum Annelida. All cytochrome c oxidase subunit I sequences (cox1 gene; the chosen region for zoological DNA barcoding) present in GenBank for Annelida, as well as for "Polychaeta", "Oligochaeta", and Hirudinea separately, were downloaded and curated for length, coverage and potential contaminations. The final datasets consisted of 9782 (Annelida), 5545 ("Polychaeta"), 3639 ("Oligochaeta"), and 598 (Hirudinea) cox1 sequences and these were either (i) used as is in an automated global barcoding gap detection analysis or (ii) further analyzed for genetic distances, separated into bins containing intraspecific and interspecific comparisons and plotted in a graph to visualize any potential global barcoding gap. Over 70 million pairwise genetic comparisons were made and results suggest that although there is a tendency towards separation, no distinct or sufficiently sized global barcoding gap exists in either of the datasets rendering future barcoding efforts at risk of erroneous specimen identifications (but local barcoding gaps may still exist allowing for the identification of specimens at lower taxonomic ranks). This seems to be especially true for earthworm taxa, which account for fully 35% of the total number of interspecific comparisons that show 0% divergence.

  20. The Potemkin Gap

    NASA Astrophysics Data System (ADS)

    Laughlin, R. B.

    2003-03-01

    for photoemission - is powerfully suppressed, and that the rest of the propagator sum rule appears as a fictitious ``gap" at the scale of U. the superfluid density is also powerfully suppressed. Thus I show by example that it is possible for a system that unambiguously superconducts to appear in low-resolution spectroscopy to be an insulator. This is not different conceptually from melted stripes, but it is exact and therefore not conceptually dependent on stripes as an ordering concept. The point of the calculation is that the difference between an insulator and a superconductor can be subtle and not necessarily elucidated by high-energy spectroscopy.

  1. Distance education: turf and technology.

    PubMed

    Pickard, M R

    1992-07-01

    Distance learning fits with the mission and strategic plan of the University of Texas at Arlington. We believe these educational opportunities in nursing are highly desirable. The Board of Nurse Examiners for the State of Texas has approved this project and the Texas Higher Education Coordinating Board has approved it as a pilot project. The school will continue evaluation and creative problem-solving in the use of distance education.

  2. Etherington's Distance Duality with Birefringence

    NASA Astrophysics Data System (ADS)

    Schuller, Frederic; Werner, Marcus

    2017-07-01

    We consider light propagation in a spacetime whose kinematics allow weak birefringence, and whose dynamics have recently been derived by gravitational closure. Revisiting the definitions of luminosity and angular diameter distances in this setting, we present a modification of the Etherington distance duality relation in a weak gravitational field around a point mass. This provides the first concrete example of how the non-metricities implied by gravitational closure of birefringent electrodynamics affect observationally testable relations.

  3. Nominal Ocular Dazzle Distance (NODD)

    DTIC Science & Technology

    2015-02-23

    release; distribution unlimited. PA Case No: TSRL-PA-14-0076. Date cleared: Aug. 20 , 2014 13. SUPPLEMENTARY NOTES 14. Abstract A simple model...and Nominal Ocular Dazzle Distance (NODD). A validated intraocular scatter model has been combined with a contrast threshold target detection model to...target can be detected , and the NODD, the minimum distance for the visual detection of a target in the presence of laser dazzle. The model is suitable

  4. Gap junctions, pannexins and pain.

    PubMed

    Spray, David C; Hanani, Menachem

    2017-06-22

    Enhanced expression and function of gap junctions and pannexin (Panx) channels have been associated with both peripheral and central mechanisms of pain sensitization. At the level of the sensory ganglia, evidence includes augmented gap junction and pannexin1 expression in glial cells and neurons in inflammatory and neuropathic pain models and increased synchrony and enhanced cross-excitation among sensory neurons by gap junction-mediated coupling. In spinal cord and in suprapinal areas, evidence is largely limited to increased expression of relevant proteins, although in several rodent pain models, hypersensitivity is reduced by treatment with gap junction/Panx1 channel blocking compounds. Moreover, targeted modulation of Cx43 expression was shown to modulate pain thresholds, albeit in somewhat contradictory ways, and mice lacking Panx1 expression globally or in specific cell types show depressed hyperalgesia. We here review the evidence for involvement of gap junctions and Panx channels in a variety of animal pain studies and then discuss ways in which gap junctions and Panx channels may mediate their action in pain processing. This discussion focusses on spread of signals among satellite glial cells, in particular intercellular Ca(2+) waves, which are propagated through both gap junction and Panx1-dependent routes and have been associated with the phenomenon of spreading depression and the malady of migraine headache with aura. Copyright © 2017. Published by Elsevier B.V.

  5. Keeping One’s Distance

    PubMed Central

    Williams, Lawrence E.; Bargh, John A.

    2008-01-01

    Current conceptualizations of psychological distance (e.g., construal-level theory) refer to the degree of overlap between the self and some other person, place, or point in time. We propose a complementary view in which perceptual and motor representations of physical distance influence people’s thoughts and feelings without reference to the self, extending research and theory on the effects of distance into domains where construal-level theory is silent. Across four experiments, participants were primed with either spatial closeness or spatial distance by plotting an assigned set of points on a Cartesian coordinate plane. Compared with the closeness prime, the distance prime produced greater enjoyment of media depicting embarrassment (Study 1), less emotional distress from violent media (Study 2), lower estimates of the number of calories in unhealthy food (Study 3), and weaker reports of emotional attachments to family members and hometowns (Study 4). These results support a broader conceptualization of distance-mediated effects on judgment and affect. PMID:18315805

  6. Categorical perception of tactile distance.

    PubMed

    Knight, Frances Le Cornu; Longo, Matthew R; Bremner, Andrew J

    2014-05-01

    The tactile surface forms a continuous sheet covering the body. And yet, the perceived distance between two touches varies across stimulation sites. Perceived tactile distance is larger when stimuli cross over the wrist, compared to when both fall on either the hand or the forearm. This effect could reflect a categorical distortion of tactile space across body-part boundaries (in which stimuli crossing the wrist boundary are perceptually elongated) or may simply reflect a localised increased in acuity surrounding anatomical landmarks (in which stimuli near the wrist are perceptually elongated). We tested these two interpretations across two experiments, by comparing a well-documented bias to perceive mediolateral tactile distances across the forearm/hand as larger than proximodistal ones along the forearm/hand at three different sites (hand, wrist, and forearm). According to the 'categorical' interpretation, tactile distances should be elongated selectively in the proximodistal axis thus reducing the anisotropy. According to the 'localised acuity' interpretation, distances will be perceptually elongated in the vicinity of the wrist regardless of orientation, leading to increased overall size without affecting anisotropy. Consistent with the categorical account, we found a reduction in the magnitude of anisotropy at the wrist, with no evidence of a corresponding localised increase in precision. These findings demonstrate that we reference touch to a representation of the body that is categorically segmented into discrete parts, which consequently influences the perception of tactile distance.

  7. A normalized Levenshtein distance metric.

    PubMed

    Yujian, Li; Bo, Liu

    2007-06-01

    Although a number of normalized edit distances presented so far may offer good performance in some applications, none of them can be regarded as a genuine metric between strings because they do not satisfy the triangle inequality. Given two strings X and Y over a finite alphabet, this paper defines a new normalized edit distance between X and Y as a simple function of their lengths (|X| and |Y|) and the Generalized Levenshtein Distance (GLD) between them. The new distance can be easily computed through GLD with a complexity of O(|X|.|Y|) and it is a metric valued in [0, 1] under the condition that the weight function is a metric over the set of elementary edit operations with all costs of insertions/deletions having the same weight. Experiments using the AESA algorithm in handwritten digit recognition show that the new distance can generally provide similar results to some other normalized edit distances and may perform slightly better if the triangle inequality is violated in a particular data set.

  8. Out of the Shadow and Into the Spotlight: The Development of Distance Teaching in Norwegian Higher Education.

    ERIC Educational Resources Information Center

    Grepperud, Gunnar; Stokken, Anne Marie; Toska, Jan Atle

    2002-01-01

    The development of distance education in Norway has had to bridge the gap between two systems: a large network of public universities and colleges and a small network of public and private agencies that included distance education and adult education organizations. This mixture of public and private sectors has led to new and more hybrid forms of…

  9. Communication, Social, and Critical Thinking Skills of Students with Low-Power-Distance Teachers in a High-Power-Distance Country

    ERIC Educational Resources Information Center

    Muega, Michael Arthus; Acido, Maricris; Lusung-Oyzon, Vanessa

    2016-01-01

    This paper is aimed at giving a clearer picture of the power gap that exists between a group of Filipino students and their teachers in a laboratory school in a state university in the Philippines. This study emerged from the assumption that power distance between Filipino students and their teachers could help explain the level of their ability…

  10. Wide band gap gallium arsenide nanoparticles fabricated using plasma method

    SciTech Connect

    Jain, D.; Mangla, O.; Roy, S.

    2016-05-23

    In this paper, we have reported the fabrication of gallium arsenide (GaAs) nanoparticles on quartz placed at distance of 4.0 cm, 5.0 cm and 6.0 cm, respectively from top of anode. The fabrication has been carried out by highly energetic and high fluence ions of GaAs produced by hot, dense and extremely non-equilibrium plasma in a modified dense plasma focus device. GaAs nanoparticles have mean size of about 23 nm, 16 nm and 14 nm for deposition at a distance of 4.0 cm, 5.0 cm and 6.0 cm, respectively. The nanoparticles are crystalline in nature as evident from X-ray diffraction patterns. The band gap of nanoparticles is found to increase from 1.425 eV to 5.37 eV at 4.0 cm distance, which further increases as distance increases. The wide band gap observed for fabricated GaAs nanoparticles suggest the possible applications of nanoparticles in laser systems.

  11. On the relationship between pedestrian gap acceptance and time to arrival estimates.

    PubMed

    Petzoldt, Tibor

    2014-11-01

    The identification of safe gaps between passing cars when crossing a street is a task most of us accomplish successfully on a daily basis. Objectively, how safe a specific gap is, is mainly dependent on how long it would take the approaching vehicle to arrive (time to arrival; TTA). Common sense might suggest that TTA is the basis for pedestrians' gap selection. However, it has been shown repeatedly that vehicle approach speed has a substantial influence on the size of chosen gaps. At higher speeds, pedestrians tend to accept smaller time gaps, i.e. they initiate riskier crossings. Some researchers have gone so far as to suggest that pedestrians rely more on physical distance of a vehicle in their crossing decisions than TTA. Yet, at the same time, there is evidence that TTA estimates themselves are influenced by object approach speed. It is suspected that pedestrians are more apt to base their decisions on systematically distorted TTA estimates, rather than physical distance. The goal of the two experiments described in this article was to explore the relationship between gap acceptance and TTA estimation. Participants were presented with video clips of approaching vehicles, and were either required to indicate a crossing decision, or to estimate TTA. Results show the typical effects of speed (smaller gaps at higher speed, lower TTA estimate at lower speed) and age (larger gaps for older participants). However, when using subjective time gap size (the TTA estimate) instead of objective time gap size to predict gap acceptance, the effect of speed either disappeared (Experiment I) or decreased substantially (Experiment II). The results indicate that systematic differences in TTA estimates can be a reasonable explanation for the effect of speed on gap acceptance. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Acculturative Family Distancing (AFD) and Depression in Chinese American Families

    PubMed Central

    Hwang, Wei-Chin; Wood, Jeffrey J.; Fujimoto, Ken

    2010-01-01

    Objective Our knowledge of acculturative processes and their impact on immigrant families remains quite limited. Acculturative Family Distancing (AFD) is the distancing that occurs between immigrant parents and their children, and is caused by breakdowns in communication and cultural value differences. It is a more proximal and problem-focused formulation of the acculturation gap and is hypothesized to increase depression via family conflict. Method Data were collected from 105 Chinese American high school students and their mothers. Rasch modeling was used to refine the AFD measure and structural equation modeling was used to determine the effects of AFD on youth and maternal depression. Results Findings indicate that greater AFD was associated with higher depressive symptoms and risk for clinical depression. Family conflict partially mediated this relation for youth, whereas for mothers, AFD directly increased risk for depression. Greater mother-child heritage enculturation discrepancies were associated with greater mother and child AFD. Mainstream acculturation discrepancies and language gaps between mothers and youth were not significantly associated with any of the primary outcome variables. Conclusions Results highlight the need to better understand how AFD and other acculturation-gap phenomena affect immigrant mental health. They also underscore the need to develop prevention and intervention programs that target communication difficulties and intergenerational cultural value differences. PMID:20873901

  13. Acculturative family distancing (AFD) and depression in Chinese American families.

    PubMed

    Hwang, Wei-Chin; Wood, Jeffrey J; Fujimoto, Ken

    2010-10-01

    Knowledge of acculturative processes and their impact on immigrant families remains quite limited. Acculturative family distancing (AFD) is the distancing that occurs between immigrant parents and their children and is caused by breakdowns in communication and cultural value differences. It is a more proximal and problem-focused formulation of the acculturation gap and is hypothesized to increase depression via family conflict. Data were collected from 105 Chinese American high school students and their mothers. Rasch modeling was used to refine the AFD measure, and structural equation modeling was used to determine the effects of AFD on youth and maternal depression. Findings indicate that greater AFD was associated with higher depressive symptoms and risk for clinical depression. Family conflict partially mediated this relation for youths, whereas for mothers, AFD directly increased risk for depression. Greater mother-child heritage enculturation discrepancies were associated with greater mother and child AFD. Mainstream acculturation discrepancies and language gaps between mothers and youths were not significantly associated with any of the primary outcome variables. Results highlight the need for better understanding of how AFD and other acculturation-gap phenomena affect immigrant mental health. They also underscore the need for prevention and intervention programs that target communication difficulties and intergenerational cultural value differences. Copyright 2010 APA, all rights reserved.

  14. Eight electrode optical readout gap

    DOEpatents

    Boettcher, Gordon E.; Crain, Robert W.

    1985-01-01

    A protective device for a plurality of electrical circuits includes a pluity of isolated electrodes forming a gap with a common electrode. An output signal, electrically isolated from the circuits being monitored, is obtained by a photosensor viewing the discharge gap through an optical window. Radioactive stabilization of discharge characteristics is provided for slowly changing voltages and carbon tipped dynamic starters provide desirable discharge characteristics for rapidly varying voltages. A hydrogen permeation barrier is provided on external surfaces of the device.

  15. 14 CFR 23.75 - Landing distance.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Landing distance. 23.75 Section 23.75... distance. The horizontal distance necessary to land and come to a complete stop from a point 50 feet above... distance would be increased when a landing is made with that engine inoperative, the landing distance must...

  16. 14 CFR 23.75 - Landing distance.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Landing distance. 23.75 Section 23.75... distance. The horizontal distance necessary to land and come to a complete stop from a point 50 feet above... distance would be increased when a landing is made with that engine inoperative, the landing distance must...

  17. Perceived distance during golf putting.

    PubMed

    Hasegawa, Yumiko; Koyama, Satoshi; Inomata, Kimihiro

    2013-12-01

    This study examined the effect of anxiety states on the relationship between golf-putting distance and performance in an environment requiring high movement accuracy. Twenty-three amateur golfers attempted 15 putts at each of three putting distances, 1.25, 1.50, and 1.75m, under conditions characterized by both control demands and pressure. All attempts were recorded, and kinematic features were analyzed. Under conditions involving an audience and a monetary reward, the mean score on the State-Trait Anxiety Inventory Y-1 and the mean heart rate increased by 14 points and 11bpm, respectively. We grouped participants on an a posteriori basis using the median split. The backswing of high-anxiety performers shortened, the downswing speed declined, and the relative time to peak club-head velocity changed when putting under pressure from 1.25m. In contrast, no change in backswing or relative time to peak velocity was observed in low-anxiety performers, although impact velocity increased under this condition. These results indicate that the degree to which both low- and high-anxiety golfers were anxious about failure affected motor control at the 1.25-m distance, suggesting that a distortion in perceived distance may result from the interaction between putting distance and anxiety related to failure during golf putting.

  18. The unassigned distance geometry problem

    DOE PAGES

    Duxbury, P. M.; Granlund, L.; Gujarathi, S. R.; ...

    2015-11-19

    Studies of distance geometry problems (DGP) have focused on cases where the vertices at the ends of all or most of the given distances are known or assigned, which we call assigned distance geometry problems (aDGPs). In this contribution we consider the unassigned distance geometry problem (uDGP) where the vertices associated with a given distance are unknown, so the graph structure has to be discovered. uDGPs arises when attempting to find the atomic structure of molecules and nanoparticles using X-ray or neutron diffraction data from non-crystalline materials. Rigidity theory provides a useful foundation for both aDGPs and uDGPs, though itmore » is restricted to generic realizations of graphs, and key results are summarized. Conditions for unique realization are discussed for aDGP and uDGP cases, build-up algorithms for both cases are described and experimental results for uDGP are presented.« less

  19. Individual differences in distance perception

    PubMed Central

    Jackson, Russell E.

    2009-01-01

    Distance perception is among the most pervasive mental phenomena and the oldest research topics in behavioural science. However, we do not understand well the most pervasive finding of distance perception research, that of large individual differences. There are large individual differences in acrophobia (fear of heights), which we commonly assume consists of an abnormal fear of stimuli perceived normally. Evolved navigation theory (ENT) instead suggests that acrophobia consists of a more normal fear of stimuli perceived abnormally. ENT suggests that distance perception individual differences produce major components of acrophobia. Acrophobia tested over a broad range in the present study predicted large individual differences in distance estimation of surfaces that could produce falls. This fear of heights correlated positively with distance estimates of a vertical surface—even among non-acrophobic individuals at no risk of falling and without knowledge of being tested for acrophobia. Acrophobia score predicted magnitude of the descent illusion, which is thought to reflect the risk of falling. These data hold important implications in environmental navigation, clinical aetiology and the evolution of visual systems. PMID:19324829

  20. Individual differences in distance perception.

    PubMed

    Jackson, Russell E

    2009-05-07

    Distance perception is among the most pervasive mental phenomena and the oldest research topics in behavioural science. However, we do not understand well the most pervasive finding of distance perception research, that of large individual differences. There are large individual differences in acrophobia (fear of heights), which we commonly assume consists of an abnormal fear of stimuli perceived normally. Evolved navigation theory (ENT) instead suggests that acrophobia consists of a more normal fear of stimuli perceived abnormally. ENT suggests that distance perception individual differences produce major components of acrophobia. Acrophobia tested over a broad range in the present study predicted large individual differences in distance estimation of surfaces that could produce falls. This fear of heights correlated positively with distance estimates of a vertical surface-even among non-acrophobic individuals at no risk of falling and without knowledge of being tested for acrophobia. Acrophobia score predicted magnitude of the descent illusion, which is thought to reflect the risk of falling. These data hold important implications in environmental navigation, clinical aetiology and the evolution of visual systems.

  1. Stacking orders induced direct band gap in bilayer MoSe2-WSe2 lateral heterostructures

    PubMed Central

    Hu, Xiaohui; Kou, Liangzhi; Sun, Litao

    2016-01-01

    The direct band gap of monolayer semiconducting transition-metal dichalcogenides (STMDs) enables a host of new optical and electrical properties. However, bilayer STMDs are indirect band gap semiconductors, which limits its applicability for high-efficiency optoelectronic devices. Here, we report that the direct band gap can be achieved in bilayer MoSe2-WSe2 lateral heterostructures by alternating stacking orders. Specifically, when Se atoms from opposite layers are stacked directly on top of each other, AA and A’B stacked heterostructures show weaker interlayer coupling, larger interlayer distance and direct band gap. Whereas, when Se atoms from opposite layers are staggered, AA’, AB and AB’ stacked heterostructures exhibit stronger interlayer coupling, shorter interlayer distance and indirect band gap. Thus, the direct/indirect band gap can be controllable in bilayer MoSe2-WSe2 lateral heterostructures. In addition, the calculated sliding barriers indicate that the stacking orders of bilayer MoSe2-WSe2 lateral heterostructures can be easily formed by sliding one layer with respect to the other. The novel direct band gap in bilayer MoSe2-WSe2 lateral heterostructures provides possible application for high-efficiency optoelectronic devices. The results also show that the stacking order is an effective strategy to induce and tune the band gap of layered STMDs. PMID:27528196

  2. Experimental determination of gap scaling in a plasma opening switch

    NASA Astrophysics Data System (ADS)

    Black, D. C.; Commisso, R. J.; Ottinger, P. F.; Swanekamp, S. B.; Weber, B. V.

    2000-09-01

    Experiments were performed to investigate the coupling between a ˜0.5 μs conduction-time, ˜0.5 MA conduction-current plasma opening switch (POS), and an electron-beam (e-beam) diode. Electrical diagnostics provided measurements of the voltage at the oil-vacuum insulator and at the diode as well as anode and cathode currents on the generator and load sides of the POS. These measurements were combined with a flow impedance model to determine the POS gap over a range of conduction times and e-beam diode impedances, and for two POS-to-load distances. A comparison of the inferred POS gap at peak power with the critical gap for magnetic insulation indicates that the POS gap is always saturated in both switch-limited and load-limited regimes. This POS gap-size scaling with load impedance is consistent with an opening mechanism dominated by erosion and not J×B forces.

  3. Three-dimensional shape optical measurement using constant gap control and error compensation

    SciTech Connect

    Park, Kyihwan; Kim, Sangyoo; Choi, Kyosoon

    2008-03-15

    The optical laser displacement sensor is widely used for noncontact measurement of the three-dimensional (3D) shape profile of the object surface. When the surface of an object has a slope variation, the sensor gain is proportionally varied according to that of the object surface. In order to solve the sensor gain variation problem, the constant gap control method is applied to adjust the gap to the nominal distance. Control error compensation is also proposed to cope with the situation even when the gap is not perfectly controlled to the nominal distance using an additional sensor attached to the actuator. 3D shape measurement applying the proposed constant gap control method shows better performances rather than the constant sensor height method.

  4. DEER Distance Measurements on Proteins

    NASA Astrophysics Data System (ADS)

    Jeschke, Gunnar

    2012-05-01

    Distance distributions between paramagnetic centers in the range of 1.8 to 6 nm in membrane proteins and up to 10 nm in deuterated soluble proteins can be measured by the DEER technique. The number of paramagnetic centers and their relative orientation can be characterized. DEER does not require crystallization and is not limited with respect to the size of the protein or protein complex. Diamagnetic proteins are accessible by site-directed spin labeling. To characterize structure or structural changes, experimental protocols were optimized and techniques for artifact suppression were introduced. Data analysis programs were developed, and it was realized that interpretation of the distance distributions must take into account the conformational distribution of spin labels. First methods have appeared for deriving structural models from a small number of distance constraints. The present scope and limitations of the technique are illustrated.

  5. Experimental investigations of argon spark gap recovery times by developing a high voltage double pulse generator.

    PubMed

    Reddy, C S; Patel, A S; Naresh, P; Sharma, Archana; Mittal, K C

    2014-06-01

    The voltage recovery in a spark gap for repetitive switching has been a long research interest. A two-pulse technique is used to determine the voltage recovery times of gas spark gap switch with argon gas. First pulse is applied to the spark gap to over-volt the gap and initiate the breakdown and second pulse is used to determine the recovery voltage of the gap. A pulse transformer based double pulse generator capable of generating 40 kV peak pulses with rise time of 300 ns and 1.5 μs FWHM and with a delay of 10 μs-1 s was developed. A matrix transformer topology is used to get fast rise times by reducing L(l)C(d) product in the circuit. Recovery Experiments have been conducted for 2 mm, 3 mm, and 4 mm gap length with 0-2 bars pressure for argon gas. Electrodes of a sparkgap chamber are of rogowsky profile type, made up of stainless steel material, and thickness of 15 mm are used in the recovery study. The variation in the distance and pressure effects the recovery rate of the spark gap. An intermediate plateu is observed in the spark gap recovery curves. Recovery time decreases with increase in pressure and shorter gaps in length are recovering faster than longer gaps.

  6. The number and size of subhalo-induced gaps in stellar streams

    NASA Astrophysics Data System (ADS)

    Erkal, Denis; Belokurov, Vasily; Bovy, Jo; Sanders, Jason L.

    2016-11-01

    Ample observational capabilities exist today to detect the small density perturbations that low-mass dark matter subhaloes impart on stellar streams from disrupting Galactic satellites. In anticipation of these observations, we investigate the expected number and size of gaps by combining an analytic prescription for gap evolution on circular orbits with the flux of subhaloes near the stream. We explore the distribution of gap sizes and depths for a typical cold stream around the Milky Way and find that for a given stream age and gap depth, each subhalo mass produces a characteristic gap size. For a stream with an age of a few Gyr, orbiting at a distance of 10-20 kpc from the Galactic centre, even modest subhaloes with a mass of 106-107 M⊙ produce gaps with sizes that are of the order of several degrees. We consider the number and distribution of gap sizes created by subhaloes with masses 105-109 M⊙, accounting for the expected depletion of subhaloes by the Milky Way disc, and present predictions for six cold streams around the Milky Way. For Pal 5, we forecast 0.7 gaps with a density depletion of at least 25 per cent and a typical gap size of 8°. Thus, there appears to be no tension between the recent non-detection of density depletions in the Pal 5 tidal tails and ΛCDM expectations. These predictions can be used to guide the scale of future gap searches.

  7. Solving the molecular distance geometry problem with inaccurate distance data

    PubMed Central

    2013-01-01

    We present a new iterative algorithm for the molecular distance geometry problem with inaccurate and sparse data, which is based on the solution of linear systems, maximum cliques, and a minimization of nonlinear least-squares function. Computational results with real protein structures are presented in order to validate our approach. PMID:23901894

  8. Solving the molecular distance geometry problem with inaccurate distance data.

    PubMed

    Souza, Michael; Lavor, Carlile; Muritiba, Albert; Maculan, Nelson

    2013-01-01

    We present a new iterative algorithm for the molecular distance geometry problem with inaccurate and sparse data, which is based on the solution of linear systems, maximum cliques, and a minimization of nonlinear least-squares function. Computational results with real protein structures are presented in order to validate our approach.

  9. Distance Education at Arm's Length: Outsourcing of Distance Education Marking.

    ERIC Educational Resources Information Center

    Smith, Erica; Coombe, Kennece

    Two research projects focused on use of casual markers (graders) for correcting and grading distance education (DE) students' work. A Charles Sturt University project convened focus groups of DE students, casual DE markers, and lecturers who "managed" markers to uncover concerns. University of South Australia research focused on pedagogical issues…

  10. Using Web-Based Distance Learning to Reduce Cultural Distance

    ERIC Educational Resources Information Center

    Wong, L. Fai; Trinidad, S. G.

    2004-01-01

    In recent years, Web-based distance learning (WBDL) systems have become a popular learning environment for many western learners. While it has been established as an effective learning alternative, WBDL is not flourishing in Hong Kong as expected. This paper proposes that this is because Hong Kong students are not trained to learn independently…

  11. Regeneration in bottomland forest canopy gaps 6 years after variable retention harvests to enhance wildlife habitat

    Treesearch

    Daniel J. Twedt; Scott G. Somershoe

    2013-01-01

    To promote desired forest conditions that enhance wildlife habitat in bottomland forests, managers prescribed and implemented variable-retention harvest, a.k.a. wildlife forestry, in four stands on Tensas River National Wildlife Refuge, LA. These treatments created canopy openings (gaps) within which managers sought to regenerate shade-intolerant trees. Six years after...

  12. Statistical Efficiency in Distance Sampling

    PubMed Central

    Clark, Robert Graham

    2016-01-01

    Distance sampling is a technique for estimating the abundance of animals or other objects in a region, allowing for imperfect detection. This paper evaluates the statistical efficiency of the method when its assumptions are met, both theoretically and by simulation. The theoretical component of the paper is a derivation of the asymptotic variance penalty for the distance sampling estimator arising from uncertainty about the unknown detection parameters. This asymptotic penalty factor is tabulated for several detection functions. It is typically at least 2 but can be much higher, particularly for steeply declining detection rates. The asymptotic result relies on a model which makes the strong assumption that objects are uniformly distributed across the region. The simulation study relaxes this assumption by incorporating over-dispersion when generating object locations. Distance sampling and strip transect estimators are calculated for simulated data, for a variety of overdispersion factors, detection functions, sample sizes and strip widths. The simulation results confirm the theoretical asymptotic penalty in the non-overdispersed case. For a more realistic overdispersion factor of 2, distance sampling estimation outperforms strip transect estimation when a half-normal distance function is correctly assumed, confirming previous literature. When the hazard rate model is correctly assumed, strip transect estimators have lower mean squared error than the usual distance sampling estimator when the strip width is close enough to its optimal value (± 75% when there are 100 detections; ± 50% when there are 200 detections). Whether the ecologist can set the strip width sufficiently accurately will depend on the circumstances of each particular study. PMID:26950934

  13. Entropy distance: New quantum phenomena

    SciTech Connect

    Weis, Stephan; Knauf, Andreas

    2012-10-15

    We study a curve of Gibbsian families of complex 3 Multiplication-Sign 3-matrices and point out new features, absent in commutative finite-dimensional algebras: a discontinuous maximum-entropy inference, a discontinuous entropy distance, and non-exposed faces of the mean value set. We analyze these problems from various aspects including convex geometry, topology, and information geometry. This research is motivated by a theory of infomax principles, where we contribute by computing first order optimality conditions of the entropy distance.

  14. Gametic disequilibrium and physical distance

    SciTech Connect

    Zapata, C.; Visedo, G.

    1995-07-01

    The relationship between gametic disequilibrium and physical distance between RFLPs at different gene regions is of great interest due to the current research in fine gene mapping. A recent review found that gametic disequilibrium nearly always correlates significantly with physical distance in genomic regions greater than 50 to 60 kb in size, but it does not do so in smaller genomic regions. This conclusion is based on an analysis which is inappropriate as the r disequilibrium coefficient is frequency dependent, which disqualifies it from comparing disequilibrium between pairs of loci with different allelic frequencies. 11 refs., 2 tabs.

  15. Long working distance interference microscope

    DOEpatents

    Sinclair, Michael B.; DeBoer, Maarten P.; Smith, Norman F.

    2004-04-13

    Disclosed is a long working distance interference microscope suitable for three-dimensional imaging and metrology of MEMS devices and test structures on a standard microelectronics probe station. The long working distance of 10-30 mm allows standard probes or probe cards to be used. This enables nanometer-scale 3-D height profiles of MEMS test structures to be acquired across an entire wafer. A well-matched pair of reference/sample objectives is not required, significantly reducing the cost of this microscope, as compared to a Linnik microinterferometer.

  16. Ethics in Distance Education: Developing Ethical Policies.

    ERIC Educational Resources Information Center

    Gearhart, Deb

    2001-01-01

    Examines the changing world of education through distance education and discusses the need for ethics in distance education. Explains how to ethically develop policy for distance education, including Internet ethics, good practices guidelines, and involving faculty. (LRW)

  17. Towards a K-theory description of quantum hair

    SciTech Connect

    Garcia-Compean, H.; Loaiza-Brito, O.

    2012-08-24

    The first steps towards a proposal for a description of the quantum hair in 4D supersymmetric black holes in string Calabi-Yau (CY) compactifications are given. The quantum hair consisting of electric and magnetic fractional charges in black holes are derived from periods of the CY's torsion cycles. In the process a K-theory interpretation of the quantum hair in terms of the Atiyah-Hirzebruch spectral sequence is carried out. Finally, the same procedure is considered for torsion cycles of certain generalized CY's threefolds such as half-flat manifolds.

  18. Stabilizers for GAP and GAP-based Propellants Interim Report

    DTIC Science & Technology

    2008-10-09

    the m j o r deconposit inn pathways of GAP and U P prope l lan ts i n o r d e r to i n p r o w long term storage stabi l i ty. Model c- s inw...la t i ng t h e ut ido-bear ing frmctional units of GAP ( a z i d e adjacent t o po lye ther k k b o n e , az ide sd jacent t o terminal...binder i n prope l lan t -ag ing studies has varied accord2~g t o the to t of GAP used. This v a r i a b i l i t y my k linked to residual i n p

  19. Revealing the optoelectronic and thermoelectric properties of the Zintl quaternary arsenides ACdGeAs{sub 2} (A = K, Rb)

    SciTech Connect

    Azam, Sikander; Khan, Saleem Ayaz; Goumri-Said, Souraya

    2015-10-15

    Highlights: • Zintl tetragonal phase ACdGeAs{sub 2} (A = K, Rb) are chalcopyrite and semiconductors. • Their direct band gap is suitable for PV, optolectronic and thermoelectric applications. • Combination of DFT and Boltzmann transport theory is employed. • The present arsenides are found to be covalent materials. - Abstract: Chalcopyrite semiconductors have attracted much attention due to their potential implications in photovoltaic and thermoelectric applications. First principle calculations were performed to investigate the electronic, optical and thermoelectric properties of the Zintl tetragonal phase ACdGeAs{sub 2} (A = K, Rb) using the full potential linear augmented plane wave method and the Engle–Vosko GGA (EV–GGA) approximation. The present compounds are found semiconductors with direct band gap and covalent bonding character. The optical transitions are investigated via the dielectric function (real and imaginary parts) along with other related optical constants including refractive index, reflectivity and energy-loss spectrum. Combining results from DFT and Boltzmann transport theory, we reported the thermoelectric properties such as the Seebeck’s coefficient, electrical and thermal conductivity, figure of merit and power factor as function of temperatures. The present chalcopyrite Zintl quaternary arsenides deserve to be explored for their potential applications as thermoelectric materials and for photovoltaic devices.

  20. Field induced gap infrared detector

    NASA Technical Reports Server (NTRS)

    Elliott, C. Thomas (Inventor)

    1990-01-01

    A tunable infrared detector which employs a vanishing band gap semimetal material provided with an induced band gap by a magnetic field to allow intrinsic semiconductor type infrared detection capabilities is disclosed. The semimetal material may thus operate as a semiconductor type detector with a wavelength sensitivity corresponding to the induced band gap in a preferred embodiment of a diode structure. Preferred semimetal materials include Hg(1-x)Cd(x)Te, x is less than 0.15, HgCdSe, BiSb, alpha-Sn, HgMgTe, HgMnTe, HgZnTe, HgMnSe, HgMgSe, and HgZnSe. The magnetic field induces a band gap in the semimetal material proportional to the strength of the magnetic field allowing tunable detection cutoff wavelengths. For an applied magnetic field from 5 to 10 tesla, the wavelength detection cutoff will be in the range of 20 to 50 micrometers for Hg(1-x)Cd(x)Te alloys with x about 0.15. A similar approach may also be employed to generate infrared energy in a desired band gap and then operating the structure in a light emitting diode or semiconductor laser type of configuration.

  1. Explaining the Gender Wealth Gap

    PubMed Central

    Ruel, Erin; Hauser, Robert M.

    2013-01-01

    To assess and explain the United States’ gender wealth gap, we use the Wisconsin Longitudinal Study to examine wealth accumulated by a single cohort over 50 years by gender, by marital status, and limited to the respondents who are their family’s best financial reporters. We find large gender wealth gaps between currently married men and women, and never-married men and women. The never-married accumulate less wealth than the currently married, and there is a marital disruption cost to wealth accumulation. The status-attainment model shows the most power in explaining gender wealth gaps between these groups explaining about one-third to one-half of the gap, followed by the human-capital explanation. In other words, a lifetime of lower earnings for women translates into greatly reduced wealth accumulation. A gender wealth gap remains between married men and women after controlling for the full model that we speculate may be related to gender differences in investment strategies and selection effects. PMID:23264038

  2. Explaining the gender wealth gap.

    PubMed

    Ruel, Erin; Hauser, Robert M

    2013-08-01

    To assess and explain the United States' gender wealth gap, we use the Wisconsin Longitudinal Study to examine wealth accumulated by a single cohort over 50 years by gender, by marital status, and limited to the respondents who are their family's best financial reporters. We find large gender wealth gaps between currently married men and women, and between never-married men and women. The never-married accumulate less wealth than the currently married, and there is a marital disruption cost to wealth accumulation. The status-attainment model shows the most power in explaining gender wealth gaps between these groups explaining about one-third to one-half of the gap, followed by the human-capital explanation. In other words, a lifetime of lower earnings for women translates into greatly reduced wealth accumulation. After controlling for the full model, we find that a gender wealth gap remains between married men and women that we speculate may be related to gender differences in investment strategies and selection effects.

  3. Crop yield gaps in Cameroon.

    PubMed

    Yengoh, Genesis T; Ardö, Jonas

    2014-03-01

    Although food crop yields per hectare have generally been increasing in Cameroon since 1961, the food price crisis of 2008 and the ensuing social unrest and fatalities raised concerns about the country's ability to meet the food needs of its population. This study examines the country's potential for increasing crop yields and food production to meet this food security challenge. Fuzzy set theory is used to develop a biophysical spatial suitability model for different crops, which in turn is employed to ascertain whether crop production is carried out in biophysically suited areas. We use linear regression to examine the trend of yield development over the last half century. On the basis of yield data from experimental stations and farmers' fields we assess the yield gap for major food crops. We find that yields have generally been increasing over the last half century and that agricultural policies can have significant effects on them. To a large extent, food crops are cultivated in areas that are biophysically suited for their cultivation, meaning that the yield gap is not a problem of biophysical suitability. Notwithstanding, there are significantly large yield gaps between actual yields on farmers' farms and maximum attainable yields from research stations. We conclude that agronomy and policies are likely to be the reasons for these large yield gaps. A key challenge to be addressed in closing the yield gaps is that of replenishing and properly managing soil nutrients.

  4. Distance Education and Organizational Environment

    ERIC Educational Resources Information Center

    East, Jean F.; LaMendola, Walter; Alter, Catherine

    2014-01-01

    As distance education models in social work education continue to grow, this study addresses prevalence and type of models in graduate social work programs and the perceptions of deans about the future of e-learning models of curriculum delivery. The study was an exploratory sequential mixed-methods design including a national survey of 121…

  5. Using Podcasts in Distance Education

    ERIC Educational Resources Information Center

    Koppelman, Herman

    2013-01-01

    This paper discusses three possible ways of applying podcasts in distance education: podcasts of recordings of virtual classes, podcasts produced for specific pedagogical aims, and podcasts produced by external organizations. Through a survey we gained insight in the (until now limited) experiences of our distant students with podcasts, and also…

  6. Distance Learning: Untried and Untrue

    ERIC Educational Resources Information Center

    Halfond, Jay A.

    2010-01-01

    G. K. Chesterton famously once said: "Christianity has not been tried and found wanting; it has been found difficult and not tried." This, the author believes, applies to distance learning as well. There is far too much self-congratulatory hyperbole about the growth and pervasiveness of online learning--which exaggerates reality and overlooks the…

  7. Long-distance free fall

    NASA Astrophysics Data System (ADS)

    Gallant, Joseph; Carlson, James

    1999-03-01

    We present an analysis of a situation described in Milton's epic poem "Paradise Lost" in which we calculate the distance required for a nine-day free-fall from rest to the Earth. The resulting method is completely general, and can be applied to free-fall toward other bodies and to near-Earth free-fall as well.

  8. Religious Distance Education Goes Online

    ERIC Educational Resources Information Center

    Frye, Steven B.

    2012-01-01

    Looking back on the use of distance education tools by religious groups, one word that stands out is change. The old adage "We've never done it that way before" will become less valid as religious bodies find themselves in the midst of a world inundated with online possibilities that call them to question how they interact with members…

  9. Distance Learners: Welcome to Campus!

    ERIC Educational Resources Information Center

    Schwitzer, Alan M.; Duggan, Mary H.

    2005-01-01

    Old Dominion University's distance learning program, called TELETECHNET, brings the main-campus college experience to geographically distant learners at sites across Virginia and as far away as the state of Washington, as well as to military personnel on Navy bases, carriers, and submarines. In an interesting turnabout, the Summer Institute for…

  10. Distance Learning and Technology Plan.

    ERIC Educational Resources Information Center

    King, Maxwell C.

    Brevard Community College (BCC), in Florida, undertook a review of enrollment, social and workplace trends, and institutional capabilities to determine opportunities, barriers, and implications for the institution in implementing distance education (DE) and instructional technology. Trends analyzed included enrollment shifts toward older students,…

  11. Designing a Distance Learning Facility.

    ERIC Educational Resources Information Center

    Lambert, Michael P.

    1998-01-01

    Details the design of a distance-learning facility through analysis of its functions, paper-handling requirements, and current and future communications-technology needs. It also lists special features the facility should have, including up-to-date wiring capacities for telecommunications, uplink and downlink capabilities to satellites, and…

  12. Distance Education for Technology Teachers

    ERIC Educational Resources Information Center

    Williams, P. John

    2004-01-01

    A typical definition of distance education is the delivery of instruction in a format that separates the teacher and learner, often both in time and space. It tends to be an umbrella term that may encompass more specific forms of education such as distributed learning, independent study, correspondence education, satellite education, etc. This…

  13. Quality Connection: Going the Distance

    ERIC Educational Resources Information Center

    Jenney, Timothy R.; Roupas, Eva K.

    2003-01-01

    In 1999, Virginia Beach City Public Schools launched a completely new distance learning (DL) initiative, Quality Connection. Since that time, through perseverance and creative thinking, the program has become a model of technology as well as a highly successful method of delivering services to a wide variety of stakeholders. Not only do students…

  14. Distance Education Clearinghouse Web Site.

    ERIC Educational Resources Information Center

    Adams, Kate; Martin, Sara

    A World Wide Web site, developed by University of Nebraska-Lincoln Information Services staff and funded by a NEB*SAT (Nebraska's multiple channel satellite and optical fiber educational telecommunications network) grant, provides a clearinghouse of distance education, Internet, and Web page development information that is useful to librarians and…

  15. Video surveillance using distance maps

    NASA Astrophysics Data System (ADS)

    Schouten, Theo E.; Kuppens, Harco C.; van den Broek, Egon L.

    2006-02-01

    Human vigilance is limited; hence, automatic motion and distance detection is one of the central issues in video surveillance. Hereby, many aspects are of importance, this paper specially addresses: efficiency, achieving real-time performance, accuracy, and robustness against various noise factors. To obtain fully controlled test environments, an artificial development center for robot navigation is introduced in which several parameters can be set (e.g., number of objects, trajectories and type and amount of noise). In the videos, for each following frame, movement of stationary objects is detected and pixels of moving objects are located from which moving objects are identified in a robust way. An Exact Euclidean Distance Map (E2DM) is utilized to determine accurately the distances between moving and stationary objects. Together with the determined distances between moving objects and the detected movement of stationary objects, this provides the input for detecting unwanted situations in the scene. Further, each intelligent object (e.g., a robot), is provided with its E2DM, allowing the object to plan its course of action. Timing results are specified for each program block of the processing chain for 20 different setups. So, the current paper presents extensive, experimentally controlled research on real-time, accurate, and robust motion detection for video surveillance, using E2DMs, which makes it a unique approach.

  16. Delineating Personal Distance and Territoriality

    ERIC Educational Resources Information Center

    Becker, Franklin D.; Mayo, Clara

    1971-01-01

    Two concepts describing human special behavior are delineated. A field experiment was designed to test whether personal belongings left as markers in public areas (i.e. cafeteria setting) function to protect a territory or to maintain a comfortable social distance. It is suggested the term territory" be restricted to situations in which the space…

  17. Measuring Distances Using Digital Cameras

    ERIC Educational Resources Information Center

    Kendal, Dave

    2007-01-01

    This paper presents a generic method of calculating accurate horizontal and vertical object distances from digital images taken with any digital camera and lens combination, where the object plane is parallel to the image plane or tilted in the vertical plane. This method was developed for a project investigating the size, density and spatial…

  18. A Distance Learning Case Study.

    ERIC Educational Resources Information Center

    Boord, Patricia M.

    1998-01-01

    To address diminishing resources and increased training demands, the Operational Training Unit (OTU) of the Federal Bureau of Investigation has saved almost $2 million by developing a distance education course to replace one full week of training at the FBI Academy. Discussion focuses on major issues faced by OTU in designing/delivering this…

  19. Communication Barriers in Distance Education

    ERIC Educational Resources Information Center

    Isman, Aytekin; Dabaj, Fahme; Altinay, Fahriye; Altinay, Zehra

    2003-01-01

    Communication is a key concept as being the major tool for people in order to satisfy their needs. It is an activity which refers as process and effective communication requires qualified communication with the elimination of communication barriers. As it is known, distance education is a new trend by following contemporary facilities and tools…

  20. Vocational Education at a Distance

    ERIC Educational Resources Information Center

    Dodds, Tony

    1973-01-01

    As a case study of the potential of teaching from a distance for technical and vocational training, the author has described the new, experimental Mauritius College of the Air, located on an island in the Indian Ocean, which promotes education through radio and television broadcasts, correspondence, and occasional face-to-face tuition. (EA)

  1. Ethical Considerations in Distance Education.

    ERIC Educational Resources Information Center

    Reed, Diane; Sork, Thomas J.

    1990-01-01

    Discusses issues in distance education for adults that can affect the welfare of others and suggests ethical sensitivity is needed. Ethical issues addressed include admission and retention of students; course development and presentation; program and course marketing; administrative issues; learner/instructor interaction; and evaluation. (29…

  2. Quality Assurance in Distance Education.

    ERIC Educational Resources Information Center

    Zuniga, Etter; Krauth, Barbara

    1996-01-01

    This publication is one of a series designed as a companion to the Western Interstate Commission for Higher Education (WICHE)'s fact book, "Policy Indicators for Higher Education: WICHE States." The title article maintains that the growth of distance learning programs has heightened existing concerns about their quality. Institutions can…

  3. Next Generation Distance Education Systems.

    ERIC Educational Resources Information Center

    Saba, Farhad, Ed.

    2000-01-01

    Discusses next generation distance education systems, which include research in cognitive science, systems science, and communication theory to provide a learning environment with student autonomy congruent to prior learning, learning objectives, and content materials to be mastered. Describes Advanced Distributed Learning (ADL), object…

  4. Student Preparedness for Distance Education.

    ERIC Educational Resources Information Center

    Mattice, Nancy J.; Dixon, Phillip Scott

    This paper presents the results of a student survey on computer-mediated distance education (DE) at the College of the Canyons. The survey queried students about whether DE fit their lifestyle, previous DE courses, access to a computer, the Internet and e-mail, and whether they would enroll in an on-line course. A total of 906 surveys were…

  5. Lessons in Developing Distance Learning.

    ERIC Educational Resources Information Center

    Gant, Lenora Peters

    1996-01-01

    Describes the use of video teletraining (VTT) for distance learning in the Department of Defense. Topics include planning and organizing the VTT facility, staff development, site facilitators, the necessity of protocol, instructional design and development strategies, student involvement and interactivity, and evaluation and assessment. (LRW)

  6. Designing a Distance Learning Facility.

    ERIC Educational Resources Information Center

    Lambert, Michael P.

    1998-01-01

    Details the design of a distance-learning facility through analysis of its functions, paper-handling requirements, and current and future communications-technology needs. It also lists special features the facility should have, including up-to-date wiring capacities for telecommunications, uplink and downlink capabilities to satellites, and…

  7. The Future of Distance Education.

    ERIC Educational Resources Information Center

    Saba, Farhad

    2000-01-01

    Examines factors that will influence how distance education is practiced in the first few decades of this new century. Discusses developments in digital technology; the exponential growth of knowledge about the brain, as well as physiology, chemistry, and psychology of learning; the system relationship between individual learners and instructors;…

  8. Lessons in Developing Distance Learning.

    ERIC Educational Resources Information Center

    Gant, Lenora Peters

    1996-01-01

    Describes the use of video teletraining (VTT) for distance learning in the Department of Defense. Topics include planning and organizing the VTT facility, staff development, site facilitators, the necessity of protocol, instructional design and development strategies, student involvement and interactivity, and evaluation and assessment. (LRW)

  9. Long distance tracking of birds

    NASA Technical Reports Server (NTRS)

    Cochran, W. W.

    1972-01-01

    The application of radio telemetry techniques to the long distance tracking of birds is discussed. The types of equipment developed and methods for attachment to a bird are described. The operating range of the radio transmitter receiver system is examined, and methods for acquiring and analyzing the data are explained.

  10. Interaction in Distance Nursing Education

    ERIC Educational Resources Information Center

    Boz Yuksekdag, Belgin

    2012-01-01

    The purpose of this study is to determine psychiatry nurses' attitudes toward the interactions in distance nursing education, and also scrunize their attitudes based on demographics and computer/Internet usage. The comparative relational scanning model is the method of this study. The research data were collected through "The Scale of Attitudes of…

  11. 78 FR 21344 - In the Matter of: Andro Telemi, a/k/a Andre Telimi, a/k/a Andre Telemi; 8868 Bluffdale Drive, La...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-10

    ... Bureau of Industry and Security In the Matter of: Andro Telemi, a/k/a Andre Telimi, a/k/a Andre Telemi..., in the U.S. District Court, Northern District of Illinois, Andro Telemi, a/k/a Andre Telimi, a/k/a... under home confinement, 500 hours of community service, a fine of $10,000 and a $100 assessment. Telemi...

  12. A comparison of histogram distance metrics for content-based image retrieval

    NASA Astrophysics Data System (ADS)

    Zhang, Qianwen; Canosa, Roxanne L.

    2014-03-01

    The type of histogram distance metric selected for a CBIR query varies greatly and will affect the accuracy of the retrieval results. This paper compares the retrieval results of a variety of commonly used CBIR distance metrics: the Euclidean distance, the Manhattan distance, the vector cosine angle distance, histogram intersection distance, χ2 distance, Jensen-Shannon divergence, and the Earth Mover's distance. A training set of ground-truth labeled images is used to build a classifier for the CBIR system, where the images were obtained from three commonly used benchmarking datasets: the WANG dataset (http://savvash.blogspot.com/2008/12/benchmark-databases-for-cbir.html), the Corel Subset dataset (http://vision.stanford.edu/resources_links.html), and the CalTech dataset (http://www.vision.caltech.edu/htmlfiles/). To implement the CBIR system, we use the Tamura texture features of coarseness, contrast, and directionality. We create texture histograms of the training set and the query images, and then measure the difference between a randomly selected query and the corresponding retrieved image using a k-nearest-neighbors approach. Precision and recall is used to evaluate the retrieval performance of the system, given a particular distance metric. Then, given the same query image, the distance metric is changed and performance of the system is evaluated once again.

  13. 78 FR 76814 - In the Matter of: Mohammed Soroush Mahalaty, a/k/a Mohammad Soroush,a/k/a Mike Soroush, 18...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-19

    ... Bureau of Industry and Security In the Matter of: Mohammed Soroush Mahalaty, a/k/a Mohammad Soroush, a/k/a Mike Soroush, 18 Clinton Lane, Jericho, NY 11753; Order Denying Export Privileges On October 3, 2012, in the U.S. District Court, Southern District of New York Mohammed Soroush Mahalaty, a/k/a...

  14. Narrowing the Distance: Bridging the Gap between Teaching Online and Faculty Development

    ERIC Educational Resources Information Center

    Rochefort, Beth A.

    2013-01-01

    Online education is a steadily growing industry, and financial pressure at institutions, combined with the rising demand for online education, have caused many universities and colleges to rely on adjunct faculty to staff their online courses For instructors, the transition to teaching online can pose a variety of barriers not the least of which…

  15. Bridging the Gap: Causality-at-a-Distance in Children's Categorization and Inferences about Internal Properties

    ERIC Educational Resources Information Center

    Sobel, David M.; Buchanan, David W.

    2009-01-01

    Previous research has shown that preschoolers extend labels and internal properties of objects based on those objects' causal properties, even when the causal properties conflict with the objects' perceptual appearance [Nazzi, T., & Gopnik, A. (2000). "A shift in children's use of perceptual and causal cues to categorization." "Developmental…

  16. Virtual gap dielectric wall accelerator

    DOEpatents

    Caporaso, George James; Chen, Yu-Jiuan; Nelson, Scott; Sullivan, Jim; Hawkins, Steven A

    2013-11-05

    A virtual, moving accelerating gap is formed along an insulating tube in a dielectric wall accelerator (DWA) by locally controlling the conductivity of the tube. Localized voltage concentration is thus achieved by sequential activation of a variable resistive tube or stalk down the axis of an inductive voltage adder, producing a "virtual" traveling wave along the tube. The tube conductivity can be controlled at a desired location, which can be moved at a desired rate, by light illumination, or by photoconductive switches, or by other means. As a result, an impressed voltage along the tube appears predominantly over a local region, the virtual gap. By making the length of the tube large in comparison to the virtual gap length, the effective gain of the accelerator can be made very large.

  17. Direct band gap silicon allotropes.

    PubMed

    Wang, Qianqian; Xu, Bo; Sun, Jian; Liu, Hanyu; Zhao, Zhisheng; Yu, Dongli; Fan, Changzeng; He, Julong

    2014-07-16

    Elemental silicon has a large impact on the economy of the modern world and is of fundamental importance in the technological field, particularly in solar cell industry. The great demand of society for new clean energy and the shortcomings of the current silicon solar cells are calling for new materials that can make full use of the solar power. In this paper, six metastable allotropes of silicon with direct or quasidirect band gaps of 0.39-1.25 eV are predicted by ab initio calculations at ambient pressure. Five of them possess band gaps within the optimal range for high converting efficiency from solar energy to electric power and also have better optical properties than the Si-I phase. These Si structures with different band gaps could be applied to multiple p-n junction photovoltaic modules.

  18. ABORT GAP CLEANING IN RHIC.

    SciTech Connect

    DREES,A.; AHRENS,L.; III FLILLER,R.; GASSNER,D.; MCINTYRE,G.T.; MICHNOFF,R.; TRBOJEVIC,D.

    2002-06-03

    During the RHIC Au-run in 2001 the 200 MHz storage cavity system was used for the first time. The rebucketing procedure caused significant beam debunching in addition to amplifying debunching due to other mechanisms. At the end of a four hour store, debunched beam could account for approximately 30%-40% of the total beam intensity. Some of it will be in the abort gap. In order to minimize the risk of magnet quenching due to uncontrolled beam losses at the time of a beam dump, a combination of a fast transverse kicker and copper collimators were used to clean the abort gap. This report gives an overview of the gap cleaning procedure and the achieved performance.

  19. Want to Close the Achievement Gap? Close the Teaching Gap

    ERIC Educational Resources Information Center

    Darling-Hammond, Linda

    2015-01-01

    For years now, educators have looked to international tests as a yardstick to measure how well students from the United States are learning compared with their peers. The answer has been: not so well. The United States has been falling further behind other nations and has struggled with a large achievement gap. Federal policy under No Child Left…

  20. Folk Belief Theory, the Rigor Gap, and the Achievement Gap

    ERIC Educational Resources Information Center

    Torff, Bruce

    2014-01-01

    Folk belief theory is suggested as a primary cause for the persistence of the achievement gap. In this research-supported theory, culturally specified folk beliefs about learning and teaching prompt educators to direct more rigorous curriculum to high-advantage students but not to low-advantage students, resulting in impoverished pedagogy in…

  1. Folk Belief Theory, the Rigor Gap, and the Achievement Gap

    ERIC Educational Resources Information Center

    Torff, Bruce

    2014-01-01

    Folk belief theory is suggested as a primary cause for the persistence of the achievement gap. In this research-supported theory, culturally specified folk beliefs about learning and teaching prompt educators to direct more rigorous curriculum to high-advantage students but not to low-advantage students, resulting in impoverished pedagogy in…

  2. Machine Learning Prediction of the Energy Gap of Graphene Nanoflakes Using Topological Autocorrelation Vectors.

    PubMed

    Fernandez, Michael; Abreu, Jose I; Shi, Hongqing; Barnard, Amanda S

    2016-11-14

    The possibility of band gap engineering in graphene opens countless new opportunities for application in nanoelectronics. In this work, the energy gaps of 622 computationally optimized graphene nanoflakes were mapped to topological autocorrelation vectors using machine learning techniques. Machine learning modeling revealed that the most relevant correlations appear at topological distances in the range of 1 to 42 with prediction accuracy higher than 80%. The data-driven model can statistically discriminate between graphene nanoflakes with different energy gaps on the basis of their molecular topology.

  3. Graphene-based tunable terahertz filter with rectangular ring resonator containing double narrow gaps

    NASA Astrophysics Data System (ADS)

    Su, Wei; Chen, Bingyan

    2017-09-01

    A plasmonic band-pass filter based on graphene rectangular ring resonator with double narrow gaps is proposed and numerically investigated by finite-difference time-domain (FDTD) simulations. For the filter with or without gaps, the resonant frequencies can be effectively adjusted by changing the width of the graphene nanoribbon, the coupling distance and chemical potential of graphene. In addition, by introducing narrow gaps in the rectangular ring resonators, it shows the single frequency filtering effect. Moreover, the structure also shows high sensitivity for different surrounding mediums. This work provides a novel method for designing all-optical integrated components in optical communication.

  4. Stacked insulator induction accelerator gaps

    SciTech Connect

    Houck, T.I.; Westenskow, G.A.; Kim, J.S.; Eylon, S.; Henestroza, E.; Yu, S.S.; Vanecek, D.

    1997-05-01

    Stacked insulators, with alternating layers of insulating material and conducting film, have been shown to support high surface electrical field stresses. We have investigated the application of the stacked insulator technology to the design of induction accelerator modules for the Relativistic-Klystron Two-Beam Accelerator program. The rf properties of the accelerating gaps using stacked insulators, particularly the impedance at frequencies above the beam pipe cutoff frequency, are investigated. Low impedance is critical for Relativistic-Klystron Two-Beam Accelerator applications where a high current, bunched beam is trsnsported through many accelerating gaps. An induction accelerator module designs using a stacked insulator is presented.

  5. Fast agglomerative clustering using a k-nearest neighbor graph.

    PubMed

    Fränti, Pasi; Virmajoki, Olli; Hautamäki, Ville

    2006-11-01

    We propose a fast agglomerative clustering method using an approximate nearest neighbor graph for reducing the number of distance calculations. The time complexity of the algorithm is improved from O(tauN2) to O(tauNlogN) at the cost of a slight increase in distortion; here, tau denotes the number of nearest neighbor updates required at each iteration. According to the experiments, a relatively small neighborhood size is sufficient to maintain the quality close to that of the full search.

  6. Use of Information and Communication Technology to Enhance the Information Literacy Skills of Distance Students

    ERIC Educational Resources Information Center

    Pastula, Matthew

    2010-01-01

    Information and Communication Technology (ICT) has become an integral tool in enhancing library services worldwide. This article looks at ways technology is utilized at Massey University to bridge the gap between distance students and traditional library services. There are a variety of software providers, formats and implementation practices…

  7. Use of Information and Communication Technology to Enhance the Information Literacy Skills of Distance Students

    ERIC Educational Resources Information Center

    Pastula, Matthew

    2010-01-01

    Information and Communication Technology (ICT) has become an integral tool in enhancing library services worldwide. This article looks at ways technology is utilized at Massey University to bridge the gap between distance students and traditional library services. There are a variety of software providers, formats and implementation practices…

  8. Strategies to Improve Retention of Postgraduate Business Students in Distance Education Courses: An Australian Case

    ERIC Educational Resources Information Center

    Carroll, David; Ng, Eric; Birch, Dawn

    2013-01-01

    In spite of the clear value of postgraduate business students to many providers of distance education courses, the factors affecting the retention of these students have received limited attention in the literature. In addressing this gap, this paper presents the findings of a qualitative study into the factors affecting the retention of…

  9. A structural distance effect for backward anaphora in Broca's area: an fMRI study.

    PubMed

    Matchin, William; Sprouse, Jon; Hickok, Gregory

    2014-11-01

    Accounts of the role of Broca's area in sentence comprehension range from specific syntactic operations to domain-general processes. The present study was designed to tease apart these two general accounts by measuring the BOLD response to two syntactically distinct long-distance dependencies that invoke abstractly similar predictive processes: backward anaphora and filler-gap dependencies. Previous research has observed distance effects in Broca's area for filler-gap dependencies, but not canonical anaphora, which has been interpreted in support of a syntactic movement account. However, filler-gap dependencies engage predictive mechanisms, resulting in active search for the gap, while canonical anaphora do not. Backward anaphora correct for this asymmetry as they engage a predictive mechanism that parallels the active search in filler-gap dependencies. The results revealed a distance effect in the pars triangularis of Broca's area for the backward anaphora condition, supporting a prediction-based role for this region rather than one for a particular syntactic operation. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. The Ontogeny of Gap Crossing Behaviour in Bornean Orangutans (Pongo pygmaeus wurmbii).

    PubMed

    Chappell, Jackie; Phillips, Abigail C; van Noordwijk, Maria A; Mitra Setia, Tatang; Thorpe, Susannah K S

    2015-01-01

    For orangutans, the largest predominantly arboreal primates, discontinuous canopy presents a particular challenge. The shortest gaps between trees lie between thin peripheral branches, which offer the least stability to large animals. The affordances of the forest canopy experienced by orangutans of different ages however, must vary substantially as adult males are an order of magnitude larger in size than infants during the early stages of locomotor independence. Orangutans have developed a diverse range of locomotor behaviour to cross gaps between trees, which vary in their physical and cognitive demands. The aims of this study were to examine the ontogeny of orangutan gap crossing behaviours and to determine which factors influence the distance orangutans crossed. A non-invasive photographic technique was used to quantify forearm length as a measure of body size. We also recorded locomotor behaviour, support use and the distance crossed between trees. Our results suggest that gap crossing varies with both physical and cognitive development. More complex locomotor behaviours, which utilized compliant trunks and lianas, were used to cross the largest gaps, but these peaked in frequency much earlier than expected, between the ages of 4 and 5 years old, which probably reflects play behaviour to perfect locomotor techniques. Smaller individuals also crossed disproportionately large gaps relative to their size, by using support deformation. Our results suggest that orangutans acquire the full repertoire of gap crossing techniques, including the more cognitively demanding ones, before weaning, but adjust the frequency of the use of these techniques to their increasing body size.

  11. The Ontogeny of Gap Crossing Behaviour in Bornean Orangutans (Pongo pygmaeus wurmbii)

    PubMed Central

    Chappell, Jackie; Phillips, Abigail C.; van Noordwijk, Maria A.; Mitra Setia, Tatang; Thorpe, Susannah K. S.

    2015-01-01

    For orangutans, the largest predominantly arboreal primates, discontinuous canopy presents a particular challenge. The shortest gaps between trees lie between thin peripheral branches, which offer the least stability to large animals. The affordances of the forest canopy experienced by orangutans of different ages however, must vary substantially as adult males are an order of magnitude larger in size than infants during the early stages of locomotor independence. Orangutans have developed a diverse range of locomotor behaviour to cross gaps between trees, which vary in their physical and cognitive demands. The aims of this study were to examine the ontogeny of orangutan gap crossing behaviours and to determine which factors influence the distance orangutans crossed. A non-invasive photographic technique was used to quantify forearm length as a measure of body size. We also recorded locomotor behaviour, support use and the distance crossed between trees. Our results suggest that gap crossing varies with both physical and cognitive development. More complex locomotor behaviours, which utilized compliant trunks and lianas, were used to cross the largest gaps, but these peaked in frequency much earlier than expected, between the ages of 4 and 5 years old, which probably reflects play behaviour to perfect locomotor techniques. Smaller individuals also crossed disproportionately large gaps relative to their size, by using support deformation. Our results suggest that orangutans acquire the full repertoire of gap crossing techniques, including the more cognitively demanding ones, before weaning, but adjust the frequency of the use of these techniques to their increasing body size. PMID:26154061

  12. A k-omega-multivariate beta PDF for supersonic combustion

    NASA Technical Reports Server (NTRS)

    Alexopoulos, G. A.; Baurle, R. A.; Hassan, H. A.

    1992-01-01

    In an attempt to study the interaction between combustion and turbulence in supersonic flows, an assumed PDF has been employed. This makes it possible to calculate the time average of the chemical source terms that appear in the species conservation equations. In order to determine the averages indicated in an equation, two transport equations, one for the temperature (enthalpy) variance and one for Q, are required. Model equations are formulated for such quantities. The turbulent time scale controls the evolution. An algebraic model similar to that used by Eklund et al was used in an attempt to predict the recent measurements of Cheng et al. Predictions were satisfactory before ignition but were less satisfactory after ignition. One of the reasons for this behavior is the inadequacy of the algebraic turbulence model employed. Because of this, the objective of this work is to develop a k-omega model to remedy the situation.

  13. A k-epsilon modeling of near wall turbulence

    NASA Technical Reports Server (NTRS)

    Yang, Z.; Shih, T. H.

    1991-01-01

    A k-epsilon model is proposed for turbulent bounded flows. In this model, the turbulent velocity scale and turbulent time scale are used to define the eddy viscosity. The time scale is shown to be bounded from below by the Kolmogorov time scale. The dissipation equation is reformulated using the time scale, removing the need to introduce the pseudo-dissipation. A damping function is chosen such that the shear stress satisfies the near wall asymptotic behavior. The model constants used are the same as the model constants in the commonly used high turbulent Reynolds number k-epsilon model. Fully developed turbulent channel flows and turbulent boundary layer flows over a flat plate at various Reynolds numbers are used to validate the model. The model predictions were found to be in good agreement with the direct numerical simulation data.

  14. New method for distance-based close following safety indicator.

    PubMed

    Sharizli, A A; Rahizar, R; Karim, M R; Saifizul, A A

    2015-01-01

    The increase in the number of fatalities caused by road accidents involving heavy vehicles every year has raised the level of concern and awareness on road safety in developing countries like Malaysia. Changes in the vehicle dynamic characteristics such as gross vehicle weight, travel speed, and vehicle classification will affect a heavy vehicle's braking performance and its ability to stop safely in emergency situations. As such, the aim of this study is to establish a more realistic new distance-based safety indicator called the minimum safe distance gap (MSDG), which incorporates vehicle classification (VC), speed, and gross vehicle weight (GVW). Commercial multibody dynamics simulation software was used to generate braking distance data for various heavy vehicle classes under various loads and speeds. By applying nonlinear regression analysis to the simulation results, a mathematical expression of MSDG has been established. The results show that MSDG is dynamically changed according to GVW, VC, and speed. It is envisaged that this new distance-based safety indicator would provide a more realistic depiction of the real traffic situation for safety analysis.

  15. The Semantic Distance Model of Relevance Assessment.

    ERIC Educational Resources Information Center

    Brooks, Terrence A.

    1998-01-01

    Presents the Semantic Distance Model (SDM) of Relevance Assessment, a cognitive model of the relationship between semantic distance and relevance assessment. Discusses premises of the model such as the subjective nature of information and the metaphor of semantic distance. Empirical results illustrate the effects of semantic distance and semantic…

  16. Effective Teaching in Distance Education. ERIC Digest.

    ERIC Educational Resources Information Center

    Mielke, Dan

    Distance education is an alternative method for delivering academic course work to students unable to attend traditional campus-based classes. This Digest presents information on the many forms of distance education and keys to successful teaching with distance education. Distance education is a method of education in which the learner is…

  17. Continuing Engineering Education through Distance Learning

    ERIC Educational Resources Information Center

    Baukal, C. E.

    2010-01-01

    The demand for distance continuing engineering education (CEE) is growing. This article describes the following with regard to CEE: the purpose; its importance, trends and unique challenges. Distance education can meet some of these challenges. Benefits and challenges of distance CEE are discussed along with the different types of distance CEE…

  18. The Semantic Distance Model of Relevance Assessment.

    ERIC Educational Resources Information Center

    Brooks, Terrence A.

    1998-01-01

    Presents the Semantic Distance Model (SDM) of Relevance Assessment, a cognitive model of the relationship between semantic distance and relevance assessment. Discusses premises of the model such as the subjective nature of information and the metaphor of semantic distance. Empirical results illustrate the effects of semantic distance and semantic…

  19. Lunar Slope and Distance Estimation

    NASA Astrophysics Data System (ADS)

    Young, Laurence R.; Liu, Andrew M.; Oravetz, Christopher T.

    2008-06-01

    When astronauts return to the moon, they will undertake frequent treks across unknown terrain for geological investigations. Lunar conditions which are expected to affect human terrain perception include: the lack of an atmosphere or haze, the regolith luminance properties, the absence of familiar objects, and reduced gravity. This project examines the perceptual errors in human judgment of slopes and distance on earth using lunar-like terrain. Slope estimation errors of five subjects were measured for five featureless hills in Hanksville, Utah using visual and haptic measurement methods. This experiment was replicated in Virtual Reality (VR) with 7 subjects using stereo photographs. Significant overestimations were found in both experiments. Future work will measure slope and distance judgments on the moon using photographs from Apollo missions. The findings may influence astronaut training and design of navigation aids.

  20. Distance probes of dark energy

    SciTech Connect

    Kim, A. G.; Padmanabhan, N.; Aldering, G.; Allen, S. W.; Baltay, C.; Cahn, R. N.; D’Andrea, C. B.; Dalal, N.; Dawson, K. S.; Denney, K. D.; Eisenstein, D. J.; Finley, D. A.; Freedman, W. L.; Ho, S.; Holz, D. E.; Kasen, D.; Kent, S. M.; Kessler, R.; Kuhlmann, S.; Linder, E. V.; Martini, P.; Nugent, P. E.; Perlmutter, S.; Peterson, B. M.; Riess, A. G.; Rubin, D.; Sako, M.; Suntzeff, N. V.; Suzuki, N.; Thomas, R. C.; Wood-Vasey, W. M.; Woosley, S. E.

    2015-03-01

    This document presents the results from the Distances subgroup of the Cosmic Frontier Community Planning Study (Snowmass 2013). We summarize the current state of the field as well as future prospects and challenges. In addition to the established probes using Type Ia supernovae and baryon acoustic oscillations, we also consider prospective methods based on clusters, active galactic nuclei, gravitational wave sirens and strong lensing time delays.

  1. SISAM interferometer for distance measurements.

    PubMed

    Verrier, I; Brun, G; Goure, J P

    1997-09-01

    We measure short distances with a spectromètre interférentiel à sélection par l'amplitude de la modulation (SISAM) (interferential spectrometer by selection of amplitude modulation) interferometer that correlates optical fields. We present the method and the resolution of the system. A test with a Michelson interferometer shows SISAM's ability to detect phase change in one arm of the Michelson interferometer.

  2. Cosmological parallax-distance formula

    NASA Astrophysics Data System (ADS)

    Singal, Ashok K.

    2015-09-01

    The standard cosmological parallax-distance formula, as found in the literature, including text-books and reference books on cosmology, requires a correction. This correction stems from the fact that in the standard text-book derivation it has been ignored that any chosen baseline in a gravitationally bound system does not partake in the cosmological expansion. Though the correction is available in the literature for some time, the text-books still continue to use the older, incorrect formula, and its full implications are not yet fully realized. Apart from providing an alternate correct, closed-form expression that is more suitable and convenient for computations for certain limiting cases of FRW () world models, we also demonstrate how one can compute parallax distance for the currently favored flat-space accelerating-universe (, ) cosmologies. Further, we show that the correction in parallax distance at large redshifts could amount to a factor of three or even more. Moreover, even in an infinite universe the parallax distance does not increase indefinitely with redshift and that even the farthest possible observable point may have a finite parallax angle, a factor that needs to be carefully taken into account when using distant objects as the background field against which the parallax of a foreground object is to be measured. Some other complications that could arise in parallax measurements of a distant source, like that due to the deflection of incoming light by the gravitation field of the Sun and other planetary bodies in the solar system, are pointed out.

  3. Tuning the Cepheid distance scale

    NASA Astrophysics Data System (ADS)

    Mateo, Mario

    1992-09-01

    Ongoing observational programs (both from the ground and space) will provide a significantly larger sample of galaxies with well-studied Cepheids both within the Local Group and in more distant galaxies. Recent efforts in the calibration of the Cepheid distance scale utilizing Cepheids in star clusters in the Galaxy and in the Magellanic Clouds are described. Some of the significant advantages of utilizing LMC Cepheids in particular are emphasized, and the current status of the field is summarized.

  4. Tuning the Cepheid distance scale

    NASA Technical Reports Server (NTRS)

    Mateo, Mario

    1992-01-01

    Ongoing observational programs (both from the ground and space) will provide a significantly larger sample of galaxies with well-studied Cepheids both within the Local Group and in more distant galaxies. Recent efforts in the calibration of the Cepheid distance scale utilizing Cepheids in star clusters in the Galaxy and in the Magellanic Clouds are described. Some of the significant advantages of utilizing LMC Cepheids in particular are emphasized, and the current status of the field is summarized.

  5. Distance Probes of Dark Energy

    DOE PAGES

    Kim, A. G.; Padmanabhan, N.; Aldering, G.; ...

    2015-03-15

    We present the results from the Distances subgroup of the Cosmic Frontier Community Planning Study (Snowmass 2013). This document summarizes the current state of the field as well as future prospects and challenges. In addition to the established probes using Type Ia supernovae and baryon acoustic oscillations, we also consider prospective methods based on clusters, active galactic nuclei, gravitational wave sirens and strong lensing time delays.

  6. The Widening Income Achievement Gap

    ERIC Educational Resources Information Center

    Reardon, Sean F.

    2013-01-01

    Has the academic achievement gap between high-income and low-income students changed over the last few decades? If so, why? And what can schools do about it? Researcher Sean F. Reardon conducted a comprehensive analysis of research to answer these questions and came up with some striking findings. In this article, he shows that income-related…

  7. Brain Responses to Filled Gaps

    ERIC Educational Resources Information Center

    Hestvik, Arild; Maxfield, Nathan; Schwartz, Richard G.; Shafer, Valerie

    2007-01-01

    An unresolved issue in the study of sentence comprehension is whether the process of gap-filling is mediated by the construction of empty categories (traces), or whether the parser relates fillers directly to the associated verb's argument structure. We conducted an event-related potentials (ERP) study that used the violation paradigm to examine…

  8. Closing the Teacher Quality Gap

    ERIC Educational Resources Information Center

    Haycock, Kati; Crawford, Candace

    2008-01-01

    Schools and districts rarely have a fair distribution of teacher talent. Poor children and black children are less likely to be taught by the strongest teachers and more likely to be taught by the weakest. Several districts have implemented programs to reduce the teacher quality gap. Hamilton County, Tennessee, launched an initiative that included…

  9. Multiple input electrode gap controller

    DOEpatents

    Hysinger, Christopher L.; Beaman, Joseph J.; Melgaard, David K.; Williamson, Rodney L.

    1999-01-01

    A method and apparatus for controlling vacuum arc remelting (VAR) furnaces by estimation of electrode gap based on a plurality of secondary estimates derived from furnace outputs. The estimation is preferably performed by Kalman filter. Adaptive gain techniques may be employed, as well as detection of process anomalies such as glows.

  10. Featured Image: Simulating Planetary Gaps

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2017-03-01

    The authors model of howthe above disk would look as we observe it in a scattered-light image. The morphology of the gap can be used to estimate the mass of the planet that caused it. [Dong Fung 2017]The above image from a computer simulation reveals the dust structure of a protoplanetary disk (with the star obscured in the center) as a newly formed planet orbits within it. A recent study by Ruobing Dong (Steward Observatory, University of Arizona) and Jeffrey Fung (University of California, Berkeley) examines how we can determine mass of such a planet based on our observations of the gap that the planet opens in the disk as it orbits. The authors models help us to better understand how our observations of gaps might change if the disk is inclined relative to our line of sight, and how we can still constrain the mass of the gap-opening planet and the viscosity of the disk from the scattered-light images we have recently begun to obtain of distant protoplanetary disks. For more information, check out the paper below!CitationRuobing Dong () and Jeffrey Fung () 2017 ApJ 835 146. doi:10.3847/1538-4357/835/2/146

  11. Literary Gaps Invite Creative Interaction.

    ERIC Educational Resources Information Center

    Watson, Jerry J.

    Literary gaps were identified by Wolfgang Iser in 1974 as "vacant pages" that invite the reader to reflect and enter into the text thereby motivating students to experience the text as reality. Arthur Applebee, in 1979, identified three categories to distinguish children's types of interaction with stories: (1) the complexity of literary…

  12. The Widening Income Achievement Gap

    ERIC Educational Resources Information Center

    Reardon, Sean F.

    2013-01-01

    Has the academic achievement gap between high-income and low-income students changed over the last few decades? If so, why? And what can schools do about it? Researcher Sean F. Reardon conducted a comprehensive analysis of research to answer these questions and came up with some striking findings. In this article, he shows that income-related…

  13. Bridging the Multimedia Generation Gap.

    ERIC Educational Resources Information Center

    Hurn, Janet; Thibeault, Nancy

    This paper outlines efforts at Miami University (Middletown, Ohio) to bridge the "generation gap" between students who are comfortable using computer technologies and the faculty and staff who are reluctant to use them. Two Instructional Technology Fairs were held on campus (in Springs 1995 and 1996) to show faculty, staff, students, and…

  14. Large gap magnetic suspension system

    NASA Technical Reports Server (NTRS)

    Abdelsalam, Moustafa K.; Eyssa, Y. M.

    1991-01-01

    The design of a large gap magnetic suspension system is discussed. Some of the topics covered include: the system configuration, permanent magnet material, levitation magnet system, superconducting magnets, resistive magnets, superconducting levitation coils, resistive levitation coils, levitation magnet system, and the nitrogen cooled magnet system.

  15. Multiple input electrode gap controller

    DOEpatents

    Hysinger, C.L.; Beaman, J.J.; Melgaard, D.K.; Williamson, R.L.

    1999-07-27

    A method and apparatus for controlling vacuum arc remelting (VAR) furnaces by estimation of electrode gap based on a plurality of secondary estimates derived from furnace outputs. The estimation is preferably performed by Kalman filter. Adaptive gain techniques may be employed, as well as detection of process anomalies such as glows. 17 figs.

  16. The Zero Exemplar Distance Problem

    NASA Astrophysics Data System (ADS)

    Jiang, Minghui

    Given two genomes with duplicate genes, Zero Exemplar Distance is the problem of deciding whether the two genomes can be reduced to the same genome without duplicate genes by deleting all but one copy of each gene in each genome. Blin, Fertin, Sikora, and Vialette recently proved that Zero Exemplar Distance for monochromosomal genomes is NP-hard even if each gene appears at most two times in each genome, thereby settling an important open question on genome rearrangement in the exemplar model. In this paper, we give a very simple alternative proof of this result. We also study the problem Zero Exemplar Distance for multichromosomal genomes without gene order: from one direction, we show that this problem is NP-hard even if each gene appears at most two times in each genome; from the other direction, we show that this problem admits a polynomial-time algorithm if only one of the two genomes has duplicate genes, and is fixed-parameter tractable if the parameter is the maximum number of chromosomes in each genome.

  17. Teaching Chemistry via Distance Education

    NASA Astrophysics Data System (ADS)

    Boschmann, Erwin

    2003-06-01

    This paper describes a chemistry course taught at Indiana University Purdue University, Indianapolis via television, with a Web version added later. The television format is a delivery technology; the Web is an engagement technology and is preferred since it requires student participation. The distance-laboratory component presented the greatest challenge since laboratories via distance education are not a part of the U.S. academic culture. Appropriate experiments have been developed with the consultation of experts from The Open University in the United Kingdom, Athabasca University in Canada, and Monash University in Australia. The criteria used in the development of experiments are: (1) they must be credible academic experiences equal to or better than those used on campus, (2) they must be easy to perform without supervision, (3) they must be safe, and (4) they must meet all legal requirements. An evaluation of the program using three different approaches is described. The paper concludes that technology-mediated distance education students do as well as on-campus students, but drop out at a higher rate. It is very important to communicate with students frequently, and technology tools ought to be used only if good pedagogy is enhanced by their use.

  18. Ghost imaging with broad distance

    NASA Astrophysics Data System (ADS)

    Duan, De-Yang; Zhang, Lu; Du, Shao-Jiang; Xia, Yun-Jie

    2015-10-01

    We present a scheme that is able to achieve the ghost imaging with broad distance. The physical nature of our scheme is that the different wavelength beams are separated in free space by an optical media according to the slow light or dispersion principle. Meanwhile, the equality of the optical distance of the two light arms is not violated. The photon correlation is achieved by the rotating ground glass plate (RGGP) and spatial light modulator (SLM), respectively. Our work shows that a monochromic ghost image can be obtained in the case of RGGP. More importantly, the position (or distance) of the object can be ascertained by the color of the image. Thus, the imaging and ranging processes are combined as one process for the first time to the best of our knowledge. In the case of SLM, we can obtain a colored image regardless of where the object is. Project supported by the National Natural Science Foundation of China (Grant Nos. 61178012, 11204156, 11304179, and 11247240), the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant Nos. 20133705110001 and 20123705120002), the Scientific Research Foundation for Outstanding Young Scientists of Shandong Province, China (Grant No. BS2013DX034), and the Natural Science Foundation of Shandong Province, China (Grant No. ZR2012FQ024).

  19. The Magnetotail at Lunar Distance

    NASA Astrophysics Data System (ADS)

    Sibeck, D. G.

    2015-12-01

    This presentation reviews some of the single-point observations of the magnetotail at lunar distances made by ALSEP, Explorer 33, 35, ISEE-3, and Geotail that form the framework for interpreting more recent dual-spacecraft ARTEMIS observations. Earth's distant magnetotail flaps, twists, and flattens in response to variations in the solar wind flow direction and interplanetary magnetic field (IMF) orientation. It may even disappear leaving nothing more than a wake during strongly northward IMF orientations. Standing slow mode expansion fans provide for a gradual transition between magnetotail lobe and magnetosheath plasma and magnetic field parameters. The distant neutral line may at times reside at lunar distances, creating jets of sunward-streaming plasma within the cislunar plasma sheet and layers of streaming energetic particles on its boundaries. Reconnection at near-Earth neutral lines releases antisunward-moving plasmoids that transit lunar distances, briefly expanding the diameter of the plasma sheet and magnetotail. Taken as a whole, the distant magnetotail is a fascinating plasma laboratory and a region of great important to the magnetosphere.

  20. Gaps"

    ERIC Educational Resources Information Center

    What Works Clearinghouse, 2013

    2013-01-01

    This study investigated the effect of daily quizzes on the performance of college students. Students in an introductory psychology course used their own wireless-enabled devices to take short Internet-based quizzes at the beginning of every class. The quiz items were drawn approximately equally from material covered in the readings and the…

  1. Flow noise induced by small gaps in low-Mach-number turbulent boundary layers

    NASA Astrophysics Data System (ADS)

    Hao, Jin; Wang, Meng; Ji, Minsuk; Wang, Kan

    2013-11-01

    The flow-noise induced by small gaps underneath low-Mach-number turbulent boundary layers at Reθ = 4755 is studied using large-eddy simulation and Lighthill's theory. The gap leading-edge height is 13% of the boundary-layer thickness, and the gap width and trailing-edge height are varied to investigate their effects on surface-pressure fluctuations and sound generation. The maximum surface pressure fluctuations, which increase with gap width and trailing-edge height, occur at the trailing edge or near the reattachment point if there is separation from the trailing edge. The downstream recovery towards an equilibrium boundary layer is significantly faster for gap flows compared to step flows, and the recovery distance scales with the reattachment length for gaps with trailing-edge separation. The acoustic field is dominated by the forward-facing step in the gap and resembles forward-step sound for wide gaps and/or asymmetric gaps with trailing edge higher than leading edge. In these cases, the dominant acoustic source mechanisms are the impingement of the separated shear layer from the leading edge onto the trailing edge and the unsteady separation from the trailing edge, coupled with edge diffraction. For narrow and symmetric gaps, the destructive interference of sound from the leading and trailing edges causes a significant decline in low-frequency sound and thereby creates a broad spectral peak in the mid-frequency range. The effects of gap acoustic non-compactness and free-stream convection are investigated by comparing solutions based on a compact gap Green's function with those from a boundary-element calculation. They are found to be negligible at the typical hydroacoustc Mach number of 0.01, but become significant at Mach numbers as low as 0.1 and moderately high frequencies.

  2. Quantum mechanical effects in plasmonic structures with subnanometre gaps

    PubMed Central

    Zhu, Wenqi; Esteban, Ruben; Borisov, Andrei G.; Baumberg, Jeremy J.; Nordlander, Peter; Lezec, Henri J.; Aizpurua, Javier; Crozier, Kenneth B.

    2016-01-01

    Metallic structures with nanogap features have proven highly effective as building blocks for plasmonic systems, as they can provide a wide tuning range of operating frequencies and large near-field enhancements. Recent work has shown that quantum mechanical effects such as electron tunnelling and nonlocal screening become important as the gap distances approach the subnanometre length-scale. Such quantum effects challenge the classical picture of nanogap plasmons and have stimulated a number of theoretical and experimental studies. This review outlines the findings of many groups into quantum mechanical effects in nanogap plasmons, and discusses outstanding challenges and future directions. PMID:27255556

  3. Air Gap Effects in LX-17

    SciTech Connect

    Souers, P C; Ault, S; Avara, R; Bahl, K L; Boat, R; Cunningham, B; Gidding, D; Janzen, J; Kuklo, D; Lee, R; Lauderbach, L; Weingart, W C; Wu, B; Winer, K

    2005-09-26

    Three experiments done over twenty years on gaps in LX-17 are reported. For the detonation front moving parallel to the gaps, jets of gas products were seen coming from the gaps at velocities greater than the detonation velocity. A case can be made that the jet velocity increased with gap thickness but the data is scattered. For the detonation front moving transverse to the gap, time delays were seen. The delays roughly increase with gap width, going from 0-70 ns at 'zero gap' to around 300 ns at 0.5-1 mm gap. Larger gaps of up to 6 mm width almost certainly stopped the detonation, but this was not proved. Real-time resolution of the parallel jets and determination of the actual re-detonation or failure in the transverse case needs to be done in future experiments.

  4. Emplacement Gantry Gap Analysis Study

    SciTech Connect

    R. Thornley

    2005-05-27

    To date, the project has established important to safety (ITS) performance requirements for structures, systems, and components (SSCs) based on the identification and categorization of event sequences that may result in a radiological release. These performance requirements are defined within the ''Nuclear Safety Design Bases for License Application'' (NSDB) (BSC 2005 [DIRS 171512], Table A-11). Further, SSCs credited with performing safety functions are classified as ITS. In turn, assurance that these SSCs will perform as required is sought through the use of consensus codes and standards. This gap analysis is based on the design completed for license application only. Accordingly, identification of ITS SSCs beyond those defined within the NSDB are based on designs that may be subject to further development during detail design. Furthermore, several design alternatives may still be under consideration to satisfy certain safety functions, and final selection will not be determined until further design development has occurred. Therefore, for completeness, alternative designs currently under consideration will be discussed throughout this study. This gap analysis will evaluate each code and standard identified within the ''Emplacement Gantry ITS Standards Identification Study'' (BSC 2005 [DIRS 173586]) to ensure each ITS performance requirement is fully satisfied. When a performance requirement is not fully satisfied, a gap is highlighted. This study will identify requirements to supplement or augment the code or standard to meet performance requirements. Further, this gap analysis will identify nonstandard areas of the design that will be subject to a design development plan. Nonstandard components and nonstandard design configurations are defined as areas of the design that do not follow standard industry practices or codes and standards. Whereby, assurance that an SSC will perform as required may not be readily sought though the use of consensus standards. This

  5. Observational Properties of Protoplanetary Disk Gaps

    NASA Astrophysics Data System (ADS)

    Varnière, Peggy; Bjorkman, J. E.; Frank, Adam; Quillen, Alice C.; Carciofi, A. C.; Whitney, Barbara A.; Wood, Kenneth

    2006-02-01

    We study the effects of an annular gap induced by an embedded protoplanet on disk scattered light images and the infrared spectral energy distribution (SED). We find that the outer edge of a gap is brighter in the scattered light images than a similar location in a gap-free disk. The stellar radiation that would have been scattered by material within the gap is instead scattered by the disk wall at the outer edge of the gap, producing a bright ring surrounding the dark gap in the images. Given sufficient resolution, such gaps can be detected by the presence of this bright ring in scattered light images. A gap in a disk also changes the shape of the SED. Radiation that would have been absorbed by material in the gap is instead reprocessed by the outer gap wall. This leads to a decrease in the SED at wavelengths corresponding to the temperature at the radius of the missing gap material, and to a corresponding flux increase at longer wavelengths corresponding to the temperature of the outer wall. We note, however, that the presence of an annular gap does not change the bolometric IR flux; it simply redistributes the radiation previously produced by material within the gap to longer wavelengths. Although it will be difficult on the basis of the SED alone to distinguish between the presence of a gap and other physical effects, the level of changes can be sufficiently large to be measurable with current instruments (e.g., Spitzer).

  6. Processing Filler-Gap Dependencies in a Head-Final Language

    ERIC Educational Resources Information Center

    Aoshima, Sachiko; Phillips, Colin; Weinberg, Amy

    2004-01-01

    This paper investigates the processing of long-distance filler-gap dependencies in Japanese, a strongly head-final language. Two self-paced reading experiments and one sentence completion study show that Japanese readers associate a fronted "wh"-phrase with the most deeply embedded clause of a multi-clause sentence. Experiment 1 demonstrates this…

  7. Mechanically tunable sub-10 nm metal gap by stretching PDMS substrate

    NASA Astrophysics Data System (ADS)

    Liu, Wenjie; Shen, Yang; Xiao, Guohui; She, Xiaoyi; Wang, Jianfang; Jin, Chongjun

    2017-02-01

    Manipulating light in sub-10 nm or subnanometer metal nanogaps is crucial to study the strong interaction between electromagnetic waves and matters. However, the fabrication of metallic nanogaps with precisely controlled size and high-throughput still remains a challenge. Here, we developed an approach to actively control the gap distance between adjacent metal nanoparticles from 140 nm to sub-10 nm or even 0 nm via mechanical stretching process. To demonstrate this method, we manufactured the gold disk arrays in a square lattice on the polydimethylsiloxane (PDMS) substrate through interference lithography and gold deposition, and sub-10 nm interparticle gap was achieved as exerting a strain of 100% to the PDMS substrate. Transmission spectra show a remarkable red shift of the dipole resonance with narrowing gap from 140 nm to sub-10 nm. Importantly, a universal scaling law between the gap distance in nanoscale and the stretching amount of PDMS substrate in macroscopic scale were demonstrated experimentally and theoretically. Our method can tune the gap distance continuously and reversibly, suggesting potential applications in surface-enhanced Raman scattering, single photon emitter and quantum tunneling of electric charge.

  8. Mattig's relation and dynamical distance indicators

    NASA Astrophysics Data System (ADS)

    Teerikorpi, P.; Baryshev, Yu. V.

    2016-03-01

    We discuss how the redshift (Mattig) method in the Friedmann cosmology relates to dynamical distance indicators based on Newton's gravity (Teerikorpi 2011). It belongs to the class of indicators where the relevant length inside the system is the distance itself (in this case the proper metric distance). As the Friedmann model has a Newtonian analogy, its use to infer distances has instructive similarities to classical dynamical distance indicators. In view of the theoretical exact linear distance-velocity law, we emphasize that it is conceptually correct to derive the cosmological distance via the route: redshift (primarily observed) -> space expansion velocity (not directly observed) -> metric distance (physical length in ``cm''). Important properties of the proper metric distance are summarized.

  9. Glycybridins A-K, Bioactive Phenolic Compounds from Glycyrrhiza glabra.

    PubMed

    Li, Kai; Ji, Shuai; Song, Wei; Kuang, Yi; Lin, Yan; Tang, Shunan; Cui, Zexu; Qiao, Xue; Yu, Siwang; Ye, Min

    2017-02-24

    In an attempt to discover bioactive agents from the herbal medicine Glycyrrhiza glabra (widely known as licorice), 11 new phenolic compounds, glycybridins A-K (1-11), along with 47 known phenolics (12-58) were isolated. Their structures were elucidated on the basis of extensive NMR and MS analyses as well as experimental and computed ECD data. According to the clinical therapeutic effects of licorice, enzyme or cell-based bioactivity screenings of 1-58 were conducted. A number of compounds significantly activate Nrf2, inhibit tyrosinase or PTP1B, inhibit LPS-induced NO production and NF-κB transcription, and inhibit the proliferation of human cancer cells (HepG2, SW480, A549, MCF7). Glycybridin D (4) showed moderate cytotoxic activities against the four cancer cell lines, with IC50 values ranging from 4.6 to 6.6 μM. Further studies indicated that 4 (10 mg/kg, ip) decreased tumor mass by 39.7% on an A549 human lung carcinoma xenograft mice model, but showed little toxicity.

  10. Distance Measurement Solves Astrophysical Mysteries

    NASA Astrophysics Data System (ADS)

    2003-08-01

    Location, location, and location. The old real-estate adage about what's really important proved applicable to astrophysics as astronomers used the sharp radio "vision" of the National Science Foundation's Very Long Baseline Array (VLBA) to pinpoint the distance to a pulsar. Their accurate distance measurement then resolved a dispute over the pulsar's birthplace, allowed the astronomers to determine the size of its neutron star and possibly solve a mystery about cosmic rays. "Getting an accurate distance to this pulsar gave us a real bonanza," said Walter Brisken, of the National Radio Astronomy Observatory (NRAO) in Socorro, NM. Monogem Ring The Monogem Ring, in X-Ray Image by ROSAT satellite CREDIT: Max-Planck Institute, American Astronomical Society (Click on Image for Larger Version) The pulsar, called PSR B0656+14, is in the constellation Gemini, and appears to be near the center of a circular supernova remnant that straddles Gemini and its neighboring constellation, Monoceros, and is thus called the Monogem Ring. Since pulsars are superdense, spinning neutron stars left over when a massive star explodes as a supernova, it was logical to assume that the Monogem Ring, the shell of debris from a supernova explosion, was the remnant of the blast that created the pulsar. However, astronomers using indirect methods of determining the distance to the pulsar had concluded that it was nearly 2500 light-years from Earth. On the other hand, the supernova remnant was determined to be only about 1000 light-years from Earth. It seemed unlikely that the two were related, but instead appeared nearby in the sky purely by a chance juxtaposition. Brisken and his colleagues used the VLBA to make precise measurements of the sky position of PSR B0656+14 from 2000 to 2002. They were able to detect the slight offset in the object's apparent position when viewed from opposite sides of Earth's orbit around the Sun. This effect, called parallax, provides a direct measurement of

  11. Variable Distance Angular Symbology Reader

    NASA Technical Reports Server (NTRS)

    Schramm, Harry F., Jr. (Inventor); Corder, Eric L. (Inventor)

    2006-01-01

    A variable distance angular symbology, reader utilizes at least one light source to direct light through a beam splitter and onto a target. A target may be angled relative to the impinging light beam up to and maybe even greater than 45deg. A reflected beam from the target passes through the beam splitter and is preferably directed 90deg relative to the light source through a telecentric lens to a scanner which records an image of the target such as a direct part marking code.

  12. Structural and Thermodynamic Properties of Selective Ion Binding in a K+ Channel

    PubMed Central

    Lockless, Steve W; Zhou, Ming; MacKinnon, Roderick

    2007-01-01

    Thermodynamic measurements of ion binding to the Streptomyces lividans K+ channel were carried out using isothermal titration calorimetry, whereas atomic structures of ion-bound and ion-free conformations of the channel were characterized by x-ray crystallography. Here we use these assays to show that the ion radius dependence of selectivity stems from the channel's recognition of ion size (i.e., volume) rather than charge density. Ion size recognition is a function of the channel's ability to adopt a very specific conductive structure with larger ions (K+, Rb+, Cs+, and Ba2+) bound and not with smaller ions (Na+, Mg2+, and Ca2+). The formation of the conductive structure involves selectivity filter atoms that are in direct contact with bound ions as well as protein atoms surrounding the selectivity filter up to a distance of 15 Å from the ions. We conclude that ion selectivity in a K+ channel is a property of size-matched ion binding sites created by the protein structure. PMID:17472437

  13. Introspections on the Semantic Gap

    DTIC Science & Technology

    2015-04-14

    essential goal of virtual machine introspection ( VMI ) is security policy enforcement in the presence of an untrustworthy OS. One obstacle to this goal is...ABSTRACT Introspections on the Semantic Gap Report Title An essential goal of virtual machine introspection ( VMI ) is security policy enforcement in the...machine introspection ( VMI ) is security policy enforcement in the presence of an untrustworthy OS. One obstacle to this goal is the difficulty in

  14. Military Pay Gaps and Caps.

    DTIC Science & Technology

    1994-01-01

    RATIOS AND ENLISTED RECRUIT QUALITY AND RETENTION 27 C. MILITARY-CrVIL SERVICE PAY ADJUSTMENT LINKAGE: LEGISLATIVE BACKGROUND, 1967-1993 30...DECI), which we constructed previously and have updated to include fiscal 1992. We compare pay gaps based on the ECI versus the DECI and present DECI...do. There is no claim that the levels of military and civilian pay are equal at base point. If pay levels are equal at the base point, the divergence

  15. Homolumo gap and matrix model

    SciTech Connect

    Andric, I.; Jonke, L.; Jurman, D.; Nielsen, H. B.

    2008-06-15

    We discuss a dynamical matrix model by which probability distribution is associated with Gaussian ensembles from random matrix theory. We interpret the matrix M as a Hamiltonian representing interaction of a bosonic system with a single fermion. We show that a system of second-quantized fermions influences the ground state of the whole system by producing a gap between the highest occupied eigenvalue and the lowest unoccupied eigenvalue.

  16. Obtaining oblique technique source-to-skin distances for irregular field (Clarkson) calculations: The Mayo Off-axis Distance Indicator

    SciTech Connect

    Lajoie, W.N. )

    1988-09-01

    Significant dose inhomogeneities may exist between the supraclavicular fossa (SCF) and the internal mammary chain (IMC) regions in the irregular L-shaped (hockey stick) field associated with breast cancer treatments. This dose inhomogeneity exists, in part, because of a positive air gap in the SCF and a negative air gap in the IMC locations. Independent of treatment technique, (i.e., whether anterior-posterior (AP) or oblique fields are used), accurate source-to-skin distance (SSD) values for the SCF, IMC, and axilla are necessary when doing an irregular field (Clarkson) dose calculation. However, when an oblique technique is used to treat the hockey stick field, obtaining non-central-axis SSDs is not as straightforward as when an AP technique is employed. The Mayo Off-axis Distance Indicator was constructed to slide into the blocking tray slot of the simulator or treatment machine. This mechanical measuring device provides quick and accurate SSD measurements for non-central-axis points under either AP or, more importantly, oblique treatment conditions.

  17. Minimum distance classification in remote sensing

    NASA Technical Reports Server (NTRS)

    Wacker, A. G.; Landgrebe, D. A.

    1972-01-01

    The utilization of minimum distance classification methods in remote sensing problems, such as crop species identification, is considered. Literature concerning both minimum distance classification problems and distance measures is reviewed. Experimental results are presented for several examples. The objective of these examples is to: (a) compare the sample classification accuracy of a minimum distance classifier, with the vector classification accuracy of a maximum likelihood classifier, and (b) compare the accuracy of a parametric minimum distance classifier with that of a nonparametric one. Results show the minimum distance classifier performance is 5% to 10% better than that of the maximum likelihood classifier. The nonparametric classifier is only slightly better than the parametric version.

  18. Cosmic distance duality and cosmic transparency

    SciTech Connect

    Nair, Remya; Jhingan, Sanjay; Jain, Deepak E-mail: sanjay.jhingan@gmail.com

    2012-12-01

    We compare distance measurements obtained from two distance indicators, Supernovae observations (standard candles) and Baryon acoustic oscillation data (standard rulers). The Union2 sample of supernovae with BAO data from SDSS, 6dFGS and the latest BOSS and WiggleZ surveys is used in search for deviations from the distance duality relation. We find that the supernovae are brighter than expected from BAO measurements. The luminosity distances tend to be smaller then expected from angular diameter distance estimates as also found in earlier works on distance duality, but the trend is not statistically significant. This further constrains the cosmic transparency.

  19. Comparison of Gaia and asteroseismic distances

    NASA Astrophysics Data System (ADS)

    Yıldız, M.; ćelik Orhan, Z.; Ã-rtel, S.; Roth, M.

    2017-09-01

    Asteroseismology provides fundamental properties (mass, radius and effective temperature) of solar-like oscillating stars using so-called scaling relations. These properties allow the computation of the asteroseismic distance of stars. We compare the asteroseismic distances with the recently released Gaia distances for 74 stars studied in Yıldız et al. There is a very good agreement between these two distances; for 64 of these stars, the difference is less than 10 per cent. However, a systematic difference is seen if we use the effective temperature obtained by spectroscopic methods; the Gaia distances are about 5 per cent greater than the asteroseismic distances.

  20. Lightweight Distance Bounding Protocol against Relay Attacks

    NASA Astrophysics Data System (ADS)

    Kim, Jin Seok; Cho, Kookrae; Yum, Dae Hyun; Hong, Sung Je; Lee, Pil Joong

    Traditional authentication protocols are based on cryptographic techniques to achieve identity verification. Distance bounding protocols are an enhanced type of authentication protocol built upon both signal traversal time measurement and cryptographic techniques to accomplish distance verification as well as identity verification. A distance bounding protocol is usually designed to defend against the relay attack and the distance fraud attack. As there are applications to which the distance fraud attack is not a serious threat, we propose a streamlined distance bounding protocol that focuses on the relay attack. The proposed protocol is more efficient than previous protocols and has a low false acceptance rate under the relay attack.

  1. Giving what one should: explanations for the knowledge-behavior gap for altruistic giving.

    PubMed

    Blake, Peter R

    2017-08-07

    Several studies have shown that children struggle to give what they believe that they should: the so-called knowledge-behavior gap. Over a dozen recent Dictator Game studies find that, although young children believe that they should give half of a set of resources to a peer, they typically give less and often keep all of the resources for themselves. This article reviews recent evidence for five potential explanations for the gap and how children close it with age: self-regulation, social distance, theory of mind, moral knowledge and social learning. I conclude that self-regulation, social distance, and social learning show the most promising evidence for understanding the mechanisms that can close the gap. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. The Fundamental Gap of Simplices

    NASA Astrophysics Data System (ADS)

    Lu, Zhiqin; Rowlett, Julie

    2013-04-01

    The gap function of a domain {Ω subset {R}^n} is ξ(Ω) := d^2 (λ_2 - λ_1) , where d is the diameter of Ω, and λ1 and λ2 are the first two positive Dirichlet eigenvalues of the Euclidean Laplacian on Ω. It was recently shown by Andrews and Clutterbuck (J Amer Math Soc 24:899-916, 2011) that for any convex {Ω subset {R}^n}, ξ(Ω) ≥ 3 π^2 , where the infimum occurs for n = 1. On the other hand, the gap function on the moduli space of n-simplices behaves differently. Our first theorem is a compactness result for the gap function on the moduli space of n-simplices. Next, specializing to n = 2, our second main result proves the recent conjecture of Antunes-Freitas (J Phys A: Math Theor 41(5):055201, 2008) for any triangle {T subset {R}^2}, ξ(T) ≥ 64 π^2/9 , with equality if and only if T is equilateral.

  3. Prometheus and the Keeler gap

    NASA Astrophysics Data System (ADS)

    Tajeddine, Radwan; Nicholson, Phillip D.; Hedman, Matthew M.; French, Richard G.; Tiscareno, Matthew S.; Burns, Joseph A.

    2014-11-01

    Linblad resonances with Saturn’s satellites are located at many radii in the rings. While some cause density or bending waves, others hold gap edges from spreading, like the 2:1 resonance with Mimas located at the B-ring edge, the 7:6 resonance with Janus at the A-ring edge, and the 32:31 resonance with Prometheus at the inner edge of the Keeler gap. The latter is the case of study here.Theoretically, the inner edge of the Keeler gap should have 32 regular sinusoidal lobes, where either the maximum or the minimum radius is expected to be aligned with Prometheus and rotating with its mean motion. We show that such is not the case. Fit of occultation data shows the presence of the 32:31 resonance, however, the fit residuals is as high as the amplitude of the resonance amplitude (about 2 km). Analysis of the ISS data, shows irregularities overlapping the lobes (Tiscareno et al. 2005, DPS), that follow Keplerian motion. These irregularities may be due to clumps of particles with different eccentricities than the rest of the edge particles. This phenomenon may be caused by the resonance, as it has not been observed at other circular edges were no resonance is present at their location. The ISS data also shows that the lobe’s minimum/maximum is not perfectly aligned with the longitude of Prometheus, which may be due to libration about the centre of the resonance.

  4. Time-Distance Helioseismology (Invited)

    NASA Astrophysics Data System (ADS)

    Duvall, T. L.

    2010-12-01

    Time-distance helioseismology is a method of ambient noise imaging using the solar oscillations. The basic realization that led to time-distance helioseismology was that the temporal cross correlation of the signals at two 'surface' (or photospheric) locations should show a feature at the time lag corresponding to the subsurface travel time between the locations. The temporal cross correlation, as a function of the location separation, is the Fourier transform of the spatio-temporal power spectrum of the solar oscillations, a commonly used function in helioseismology. It is therefore likely the charactistic ridge structure of the correlation function had been seen before without appreciation of its significance. Travel times are measured from the cross correlations. The times are sensitive to a number of important subsurface solar phenomena. These include sound speed variations, flows, and magnetic fields. There has been much interesting progress in the 17 years since the first paper on this subject (Duvall et al., Nature, 1993, 362, 430-432). This progress will be reviewed in this paper.

  5. Instructional design for distance learning

    NASA Astrophysics Data System (ADS)

    Bourdeau, Jacqueline; Bates, Anthony

    1996-12-01

    An intrinsic link exists between instructional design (ID) and distance learning (DL). Their inextricability in the real world raises specific problems of interest in the field of ID. In no other teaching/learning situation is ID so essential as in DL. The conditions of DL make it a necessity to have long-term instructional planning, cost analysis, curriculum and course development, instructional materials development and maintenance, delivery plans, and detailed evaluation rules. Without all of these components, DL simply could not happen. It took some time for this neccessity to be acknowledged, as can be seen in the history of DL. However, ID becomes even more critical as increasingly costly and complex means are used. Conditions of learning have special features in DL, such as the role of media, since the professor, teacher or instructor is replaced by media for either transmitting information or for organizing learning activities. In this paper, the term distance learning will be used to mean media-based, remote or asynchronous learning supported by an instructional system. This paper introduces general features of DL and examines essential aspects of ID for DL, with special emphasis on ID methodologies and on media selection.

  6. Method and apparatus for controlling electrode gap during vacuum consumable arc remelting

    DOEpatents

    Fisher, R.W.; Maroone, J.P.; Tipping, D.W.; Zanner, F.J.

    During vacuum consumable arc remelting the electrode gap between a consumable electrode and a pool of molten metal is difficult to control. The present invention monitors drop shorts by detecting a decrease in the voltage between the consumable electrode and molten pool. The drop shorts and their associated voltage reductions occur as repetitive pulses which are closely correlated to the electrode gap. Thus, the method and apparatus of the present invention controls electrode gap based upon drop shorts detected from the monitored anode-cathode voltage. The number of drop shorts are accumulated, and each time the number of drop shorts reach a predetermined number, the average period between drop shorts is calculated from this predetermined number and the time in which this number is accumulated. This average drop short period is used in a drop short period electrode gap model which determines the actual electrode gap from the drop short. The actual electrode gap is then compared with a desired electrode gap which is selected to produce optimum operating conditions and the velocity of the consumable error is varied based upon the gap error. The consumable electrode is driven according to any prior art system at this velocity. In the preferred embodiment, a microprocessor system is utilized to perform the necessary calculations and further to monitor the duration of each drop short. If any drop short exceeds a preset duration period, the consumable electrode is rapidly retracted a predetermined distance to prevent bonding of the consumable electrode to the molten remelt.

  7. The Effect of Gap Angle on Tensile Strength of Preceramic Base Metal Solder Joints.

    PubMed

    Fattahi, Farnaz; Hashemi Ardakani, Zahra; Hashemi Ardakani, Maryam

    2015-12-01

    Soldering is a process commonly used in fabricating dental prosthesis. Since most soldered prosthesis fail at the solder joints; the joint strength is of utmost importance. The purpose of this study was to evaluate the effect of gap angle on the tensile strength of base metal solder joints. A total number of 40 Ni-Cr samples were fabricated according to ADA/ISO 9693 specifications for tensile test. Samples were cut at the midpoint of the bar, and were placed at the considered angles by employing an explicitly designed device. They were divided into 4 groups regarding the gap angle; Group C (control group) with parallel gap on steady distance of 0.2mm, Group 1: 10°, Group 2: 20°, and Group3: 30° gap angles. When soldered, the specimens were all tested for tensile strength using a universal testing machine at a cross-head speed of 0.5 mm/min with a preload of 10N. Kruskal-Wallis H test was used to compare tensile strength among the groups (p< 0.05). The mean tensile strength values obtained from the study groups were respectively 307.84, 391.50, 365.18, and 368.86 MPa. The tensile strength was not statistically different among the four groups in general (p≤ 0.490). Making the gap angular at the solder joints and the subsequent unsteady increase of the gap distance would not change the tensile strength of the joint.

  8. Resolution characteristics of graded band-gap reflection-mode AlGaAs/GaAs photocathodes

    NASA Astrophysics Data System (ADS)

    Deng, Wenjuan; Zhang, Daoli; Zou, Jijun; Peng, Xincun; Wang, Weilu; Zhang, Yijun; Chang, Benkang

    2015-12-01

    The modulation transfer function (MTF) of graded band-gap AlGaAs/GaAs reflection-mode photocathodes was determined using two-dimensional Poisson and continuity equations through numerical method. Based on the MTF model, we calculated the theoretical MTF of graded and uniform band-gap reflection-mode photocathodes. We then analyzed the effects of Al composition, wavelength of incident photon, and thicknesses of AlGaAs and GaAs layer on the resolution. Calculation results show that graded band-gap structures can increase the resolution of reflection-mode photocathodes. When the spatial frequency is 800 lp/mm and wavelength is 600 nm, the resolution of graded band-gap photocathodes generally increases by 15.4-29.6%. The resolution improvement of graded band-gap photocathodes is attributed to the fact that the built-in electric field in graded band-gap photocathodes reduces the lateral diffusion distance of photoelectrons.

  9. Open and Distance Learning Today. Routledge Studies in Distance Education Series.

    ERIC Educational Resources Information Center

    Lockwood, Fred, Ed.

    This book contains the following papers on open and distance learning today: "Preface" (Daniel); "Big Bang Theory in Distance Education" (Hawkridge); "Practical Agenda for Theorists of Distance Education" (Perraton); "Trends, Directions and Needs: A View from Developing Countries" (Koul); "American…

  10. Open and Distance Learning Today. Routledge Studies in Distance Education Series.

    ERIC Educational Resources Information Center

    Lockwood, Fred, Ed.

    This book contains the following papers on open and distance learning today: "Preface" (Daniel); "Big Bang Theory in Distance Education" (Hawkridge); "Practical Agenda for Theorists of Distance Education" (Perraton); "Trends, Directions and Needs: A View from Developing Countries" (Koul); "American…

  11. Closing the Prescription Drug Coverage Gap

    MedlinePlus

    ... coverage gap discount work for brand-name drugs? Companies that make brand-name prescription drugs must sign ... Coverage Gap Discount Program. This program requires the companies to offer discounts on brand-name drugs to ...

  12. Direct Band Gap Wurtzite Gallium Phosphide Nanowires

    PubMed Central

    2013-01-01

    The main challenge for light-emitting diodes is to increase the efficiency in the green part of the spectrum. Gallium phosphide (GaP) with the normal cubic crystal structure has an indirect band gap, which severely limits the green emission efficiency. Band structure calculations have predicted a direct band gap for wurtzite GaP. Here, we report the fabrication of GaP nanowires with pure hexagonal crystal structure and demonstrate the direct nature of the band gap. We observe strong photoluminescence at a wavelength of 594 nm with short lifetime, typical for a direct band gap. Furthermore, by incorporation of aluminum or arsenic in the GaP nanowires, the emitted wavelength is tuned across an important range of the visible light spectrum (555–690 nm). This approach of crystal structure engineering enables new pathways to tailor materials properties enhancing the functionality. PMID:23464761

  13. Toward an Internally Consistent Astronomical Distance Scale

    NASA Astrophysics Data System (ADS)

    de Grijs, Richard; Courbin, Frédéric; Martínez-Vázquez, Clara E.; Monelli, Matteo; Oguri, Masamune; Suyu, Sherry H.

    2017-08-01

    Accurate astronomical distance determination is crucial for all fields in astrophysics, from Galactic to cosmological scales. Despite, or perhaps because of, significant efforts to determine accurate distances, using a wide range of methods, tracers, and techniques, an internally consistent astronomical distance framework has not yet been established. We review current efforts to homogenize the Local Group's distance framework, with particular emphasis on the potential of RR Lyrae stars as distance indicators, and attempt to extend this in an internally consistent manner to cosmological distances. Calibration based on Type Ia supernovae and distance determinations based on gravitational lensing represent particularly promising approaches. We provide a positive outlook to improvements to the status quo expected from future surveys, missions, and facilities. Astronomical distance determination has clearly reached maturity and near-consistency.

  14. Climbing the Cosmic Distance Ladder Artist Concept

    NASA Image and Video Library

    2012-10-03

    Astronomers using NASA Spitzer Space Telescope have greatly improved the cosmic distance ladder used to measure the expansion rate of the universe, its size and age. This artist concept symbolically shows a series of stars that have known distances.

  15. Gap Year: Time off, with a Plan

    ERIC Educational Resources Information Center

    Torpey, Elka Maria

    2009-01-01

    A gap year allows people to step off the usual educational or career path and reassess their future. According to people who have taken a gap year, the time away can be well worth it. This article can help a person decide whether to take a gap year and how to make the most of his time off. It describes what a gap year is, including its pros and…

  16. Sleeping distance in wild wolf packs

    USGS Publications Warehouse

    Knick, S.T.; Mech, L.D.

    1980-01-01

    Sleeping distances were observed among members of 13 wild wolf (Canis lupus) packs and 11 pairs in northeastern Minnesota to determine if the distances correlated with pack size and composition. The study utilized aerial radio-tracking and observation during winter. Pack size and number of adults per pack were inversely related to pack average sleeping distance and variability. No correlation between sleeping distance and microclimate was observed. Possible relationships between social bonding and our results are discussed.

  17. Distance-based classification of keystroke dynamics

    NASA Astrophysics Data System (ADS)

    Tran Nguyen, Ngoc

    2016-07-01

    This paper uses the keystroke dynamics in user authentication. The relationship between the distance metrics and the data template, for the first time, was analyzed and new distance based algorithm for keystroke dynamics classification was proposed. The results of the experiments on the CMU keystroke dynamics benchmark dataset1 were evaluated with an equal error rate of 0.0614. The classifiers using the proposed distance metric outperform existing top performing keystroke dynamics classifiers which use traditional distance metrics.

  18. Dimensions of distance: a comparison of classroom education and distance education.

    PubMed

    Kennedy, David M

    2002-07-01

    Distance is obviously a core issue in distance education. But distance is a factor in classroom-based education as well. Classroom-based teachers and distance educators have a common interest in the dynamics of distance. The focus of much discussion in distance education is on geographical distance and how it may be bridged. However, this focus obscures the more fundamental issue of educational distance. Educational distance includes cognitive distance, role distance and access distance. This form of distance is as potent in the classroom environment as it is in a virtual learning environment. The writer explores this theme by his analysis of the communication patterns between teacher and students in one module in a BSc Health Studies degree programme. The writer has taught this module in both distance education format and in traditional classroom-based format. His finding is that the communication time between the teacher and students in the distance education form of the module is 29% greater than the communication time in the classroom-based form. The most significant feature of the communication pattern is the greater quantity of individual communication between student and teacher in the distance education format. Both the quantity and type of the communication in each of these modes suggest that the more communication-rich distance education format has greater potential for overcoming the problems of educational distance within this module.

  19. Distance effects in electrochemical micromachining

    PubMed Central

    Xu, Lizhong; Pan, Yue; Zhao, Chuanjun

    2016-01-01

    Considering exponential dependence of currents on double-layer voltage and the feedback effect of the electrolyte resistance, a distance effect in electrochemical micromachining is found, namely that both time constant and double-layer voltage depend on the separation of electrodes. The double-layer voltage is the real voltage used in processing. Under DC voltage, the apparent voltages between two electrodes are constant for different separations, but the real voltages change with the separations. Small separations exert substantial effects on the real voltages. Accordingly, a DC-voltage small-separation electrochemical micromachining technique was proposed. The double-layer voltage drops sharply as the small separation increases. Thus, the electrochemical reactions are confined to electrode regions in very close proximity even under DC voltage. The machining precision can be significantly enhanced by reducing the voltage and separation between electrodes. With this technique, the machining of conducting materials with submicrometre precision was achieved. PMID:27581708

  20. Distance majorization and its applications.

    PubMed

    Chi, Eric C; Zhou, Hua; Lange, Kenneth

    2014-08-01

    The problem of minimizing a continuously differentiable convex function over an intersection of closed convex sets is ubiquitous in applied mathematics. It is particularly interesting when it is easy to project onto each separate set, but nontrivial to project onto their intersection. Algorithms based on Newton's method such as the interior point method are viable for small to medium-scale problems. However, modern applications in statistics, engineering, and machine learning are posing problems with potentially tens of thousands of parameters or more. We revisit this convex programming problem and propose an algorithm that scales well with dimensionality. Our proposal is an instance of a sequential unconstrained minimization technique and revolves around three ideas: the majorization-minimization principle, the classical penalty method for constrained optimization, and quasi-Newton acceleration of fixed-point algorithms. The performance of our distance majorization algorithms is illustrated in several applications.

  1. Time delay and distance measurement

    NASA Technical Reports Server (NTRS)

    Abshire, James B. (Inventor); Sun, Xiaoli (Inventor)

    2011-01-01

    A method for measuring time delay and distance may include providing an electromagnetic radiation carrier frequency and modulating one or more of amplitude, phase, frequency, polarization, and pointing angle of the carrier frequency with a return to zero (RZ) pseudo random noise (PN) code. The RZ PN code may have a constant bit period and a pulse duration that is less than the bit period. A receiver may detect the electromagnetic radiation and calculate the scattering profile versus time (or range) by computing a cross correlation function between the recorded received signal and a three-state RZ PN code kernel in the receiver. The method also may be used for pulse delay time (i.e., PPM) communications.

  2. Closing the Achievement Gap: Four States' Efforts

    ERIC Educational Resources Information Center

    Wixom, Micah Ann

    2015-01-01

    The achievement gap separating economically disadvantaged students from their more advantaged peers disproportionately affects students of color and has been the focus of discussion, research and controversy for more than 40 years. While the gap between black and white students narrowed considerably from the 1950s to the 1980s, that gap has…

  3. Calibration curves for some standard Gap Tests

    SciTech Connect

    Bowman, A.L.; Sommer, S.C.

    1989-01-01

    The relative shock sensitivities of explosive compositions are commonly assessed using a family of experiments that can be described by the generic term ''Gap Test.'' Gap tests include a donor charge, a test sample, and a spacer, or gap, between two explosives charges. The donor charge, gap material, and test dimensions are held constant within each different version of the gap test. The thickness of the gap is then varied to find the value at which 50% of the test samples will detonate. The gap tests measure the ease with a high-order detonation can be established in the test explosive, or the ''detonability,'' of the explosive. Test results are best reported in terms of the gap thickness at the 50% point. It is also useful to define the shock pressure transmitted into the test sample at the detonation threshold. This requires calibrating the gap test in terms of shock pressure in the gap as a function of the gap thickness. It also requires a knowledge of the shock Hugoniot of the sample explosive. We used the 2DE reactive hydrodynamic code with Forest Fire burn rates for the donor explosives to calculate calibration curves for several gap tests. The model calculations give pressure and particle velocity on the centerline of the experimental set-up and provide information about the curvature and pulse width of the shock wave. 10 refs., 1 fig.

  4. Closing the gap between research and management

    Treesearch

    Deborah M. Finch; Marcia Patton-Mallory

    1993-01-01

    In this paper, we evaluate the reasons for gaps in communication between researchers and natural resource managers and identify methods to close these gaps. Gaps originate from differing patterns of language use, disparities in organizational culture and values, generation of knowledge that is too narrowly-focused to solve complex problems, failure by managers to relay...

  5. Gapping in Farsi: A Crosslinguistic Investigation

    ERIC Educational Resources Information Center

    Farudi, Annahita

    2013-01-01

    This dissertation explores a longstanding challenge in work on gapping through the empirical lens of gapping in Farsi (the Tehrani variant of Modern Persian). While gapping has much in common with more uncontroversial elliptical constructions such as VPE and sluicing, it also differs from ellipsis in ways that accounts combining TP or CP…

  6. 47 CFR 73.6008 - Distance computations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 4 2011-10-01 2011-10-01 false Distance computations. 73.6008 Section 73.6008 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES RADIO BROADCAST SERVICES Class A Television Broadcast Stations § 73.6008 Distance computations. The distance between two...

  7. 49 CFR 236.741 - Distance, stopping.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Distance, stopping. 236.741 Section 236.741 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Distance, stopping. The maximum distance on any portion of any railroad which any train operating on such...

  8. 49 CFR 236.741 - Distance, stopping.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Distance, stopping. 236.741 Section 236.741 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Distance, stopping. The maximum distance on any portion of any railroad which any train operating on such...

  9. 47 CFR 73.6008 - Distance computations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Distance computations. 73.6008 Section 73.6008 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES RADIO BROADCAST SERVICES Class A Television Broadcast Stations § 73.6008 Distance computations. The distance between two...

  10. Distance Learning: Silver Bullet or Educational Apartheid?

    ERIC Educational Resources Information Center

    Greer-Pitt, Sue

    This paper discusses why distance education is not the cure all that political leaders hope it will be, and outlines some of the reasons why distance education sometimes results in education that is separate and unequal. It identifies some of the major categories of distance education: correspondence courses, one-way televised courses (broadcast,…

  11. ETUDE - European Trade Union Distance Education.

    ERIC Educational Resources Information Center

    Creanor, Linda; Walker, Steve

    2000-01-01

    Describes transnational distance learning activities among European trade union educators carried out as part of the European Trade Union Distance Education (ETUDE) project, supported by the European Commission. Highlights include the context of international trade union distance education; tutor training course; tutors' experiences; and…

  12. Quality Assurance in Distance Learning Libraries

    ERIC Educational Resources Information Center

    Tripathi, Manorama; Jeevan, V. K. J.

    2009-01-01

    Purpose: The paper aims to study how the present distance learning libraries can improve upon their existing services and introduce new ones to enhance quality of services to distance learners. Design/methodology/approach: The paper includes a review of literature on quality assurance in open and distance education in general and student support…

  13. Student Orientation in the Distance Education Classroom.

    ERIC Educational Resources Information Center

    Bergmann, Marilyn; Raleigh, Donna

    Institutions offering distance education courses realize the value that well-trained and well-prepared faculty contribute to the success of their distance education programs. However, taking approximately a half-hour in the first session of any course to prepare the students for their distance education experience will add to the success of the…

  14. Calibrating Reach Distance to Visual Targets

    ERIC Educational Resources Information Center

    Mon-Williams, Mark; Bingham, Geoffrey P.

    2007-01-01

    The authors investigated the calibration of reach distance by gradually distorting the haptic feedback obtained when participants grasped visible target objects. The authors found that the modified relationship between visually specified distance and reach distance could be captured by a straight-line mapping function. Thus, the relation could be…

  15. Distance Education Practices at One Community College.

    ERIC Educational Resources Information Center

    Abram, Suzanne L.

    This paper examines distance education at one community college, providing data on the strengths and weaknesses of distance learning and the effectiveness of various delivery methods. Part 1 offers an account of one student's concerns about a distance education course focusing on logic and computers. The student was enrolled in an electronics…

  16. Perspectives of Research on Distance Education.

    ERIC Educational Resources Information Center

    Holmberg, Borje

    The history of research on distance education was studied. Major research done on distance education in such diverse areas as the United States, Venezuela, and Europe was analyzed. It was discovered that the earliest attempts to develop theories of distance education were mainly concerned with identifying its very concept. Like most educational…

  17. Analysing designed experiments in distance sampling

    Treesearch

    Stephen T. Buckland; Robin E. Russell; Brett G. Dickson; Victoria A. Saab; Donal N. Gorman; William M. Block

    2009-01-01

    Distance sampling is a survey technique for estimating the abundance or density of wild animal populations. Detection probabilities of animals inherently differ by species, age class, habitats, or sex. By incorporating the change in an observer's ability to detect a particular class of animals as a function of distance, distance sampling leads to density estimates...

  18. Rough Way for Academics: Distance Education

    ERIC Educational Resources Information Center

    Gursul, Fatih

    2010-01-01

    This study aims to compare the academics' perceptions about face to face and distance education, beside finding out the contributions of distance education to them, difficulties they experience in synchronous and asynchronous distance education environments and suggestions for possible solutions of the existing problems. The sample consists of 52…

  19. Learning at a Distance: Engaged or Not?

    ERIC Educational Resources Information Center

    Chen, Pu-Shih Daniel; Gonyea, Robert; Kuh, George

    2008-01-01

    In this study, Pu-Shih Chen, Robert Gonyea, and George Kuh compare the engagement of distance learners in educationally effective activities with that of their campus-based counterparts and compare the engagement of older distance learners relative to younger online students. Although distance learning is the fastest growing segment of…

  20. The History of Distance Education in Australia

    ERIC Educational Resources Information Center

    Stacey, Elizabeth

    2005-01-01

    Australia's large distances and widely distributed population has meant that distance education has been an important part of its history. From the earliest provision of schooling by mail through a series of correspondence schools, both state and federal governments have provided a sound infrastructure to support distance education. Innovative…

  1. Quality Assurance in Distance Learning Libraries

    ERIC Educational Resources Information Center

    Tripathi, Manorama; Jeevan, V. K. J.

    2009-01-01

    Purpose: The paper aims to study how the present distance learning libraries can improve upon their existing services and introduce new ones to enhance quality of services to distance learners. Design/methodology/approach: The paper includes a review of literature on quality assurance in open and distance education in general and student support…

  2. Distance Education at Conventional Universities in Germany.

    ERIC Educational Resources Information Center

    Kappel, Hans-Henning; Lehmann, Burkhard; Loeper, Joachim

    2002-01-01

    Reviews developments in German distance education from the Fernuniversitat in the 1970s to the hybridized (face-to-face and distance education) programs at conventional universities. Discusses the work of the German Association for Distance Education and two dual-mode programs: the master of arts degree at the University of Koblenz-Landau and the…

  3. Tidewater Community College Distance Learning Report.

    ERIC Educational Resources Information Center

    Tidewater Community Coll., Norfolk, VA.

    This study of distance learning at Tidewater Community College (TCC) was conducted to determine enrollment patterns, retention, and success in distance learning courses and student perceptions. Distance learning was defined as students enrolled in one of three modes of course delivery: telecourse, online, and compressed video. The time frame for…

  4. Distance Education in Asia and the Pacific.

    ERIC Educational Resources Information Center

    Cahill, Bruce, Ed.

    1985-01-01

    Issues related to the use of distance education are discussed in this bulletin, which also summarizes the status of distance education in 26 countries of Asia and the Pacific. Section 1 contains a rationale for distance education and points out possibilities offered by advances in communication technologies. Section 2 gives country-by-country…

  5. Distance Education in Papua New Guinea.

    ERIC Educational Resources Information Center

    Avalos, Beatrice, Ed.

    1991-01-01

    The theme of this special double serial issue is "Distance Education in Papua New Guinea." The following articles are featured: (1) "Distance Education in Papua New Guinea" (John Lynch); (2) "Distance Education in Papua New Guinea: Context, Issues and Prospects" (Michael Crossley and Richard Guy); (3) "Distance…

  6. Learning at a Distance: Engaged or Not?

    ERIC Educational Resources Information Center

    Chen, Pu-Shih Daniel; Gonyea, Robert; Kuh, George

    2008-01-01

    In this study, Pu-Shih Chen, Robert Gonyea, and George Kuh compare the engagement of distance learners in educationally effective activities with that of their campus-based counterparts and compare the engagement of older distance learners relative to younger online students. Although distance learning is the fastest growing segment of…

  7. Distance Education Support in University Libraries

    ERIC Educational Resources Information Center

    Snyder, Carolyn A.; Carter, Howard; Hostetler, Jerry C.

    2004-01-01

    This article describes the current distance education environment for university libraries and the distance education library services for faculty and students. The authors surveyed selected Association of Research Libraries (ARL) members to determine current services and the changes in distance education library services since the 1996 ARL SPEC…

  8. The Distancing Question in Online Education

    ERIC Educational Resources Information Center

    Russell, Glenn

    2005-01-01

    Intellectuals in many fields have long argued that, as the distance between people increases, the possibility for genuine empathy between them decreases. In this article, the author argues that distancing has as-yet unexplored pragmatic consequences in online education. As he has argued elsewhere (Russell 2004), distancing can be understood as…

  9. 2007-08 Distance Education Report

    ERIC Educational Resources Information Center

    Nevada System of Higher Education, 2008

    2008-01-01

    This report focuses on distance education within the Nevada System of Higher Education (NSHE) for the 2007-08 academic year and provides documentation of the substantial growth of distance education within all colleges and universities. Distance education is a field of continuous improvement and change, and NSHE institutions are constantly…

  10. Drive for dough. PGA Tour Golfers' tee shot functional accuracy, distance and hole score.

    PubMed

    Hellström, John; Nilsson, Johnny; Isberg, Leif

    2014-01-01

    A player's ability to score low is critical to the tournament outcome in golf. The relationships of round scores to fairways hit in regulation or striking distance on two holes per round have been investigated before with some disagreement. The purpose is therefore to examine the relationships of par-4 and par-5 hole scores to tee shot functional accuracy and distance, measured as lie of the ball and penalty, and striking distance or distance to the pin for the second shot. Such information is possible to collect without interviewing players. The best US Professional Golfers' Association Tour players' statistics during a season are used, provided by the Professional Golfers' Association Tour and ShotLink. Distance was measured with laser equipment. The results include significant (P < 0.05) correlations between score and striking distance or distance to pin, when hitting rough but not fairway on par-4s and when hitting fairway and rough on par-5s. It is therefore relevant, for performance, to consider the type of fairway miss as well as the striking distance in relation to the par and length of the hole. The findings can be considered when making gap and needs profiles, and when making tactical decisions for tee shots on different types of holes.

  11. Gap junctions - guards of excitability.

    PubMed

    Stroemlund, Line Waring; Jensen, Christa Funch; Qvortrup, Klaus; Delmar, Mario; Nielsen, Morten Schak

    2015-06-01

    Cardiomyocytes are connected by mechanical and electrical junctions located at the intercalated discs (IDs). Although these structures have long been known, it is becoming increasingly clear that their components interact. This review describes the involvement of the ID in electrical disturbances of the heart and focuses on the role of the gap junctional protein connexin 43 (Cx43). Current evidence shows that Cx43 plays a crucial role in organizing microtubules at the intercalated disc and thereby regulating the trafficking of the cardiac sodium channel NaV1.5 to the membrane.

  12. Long-gap esophageal atresia.

    PubMed

    Shieh, Hester F; Jennings, Russell W

    2017-04-01

    The management of long-gap esophageal atresia remains challenging with limited consensus on the definition, evaluation, and surgical approach to treatment. Efforts to preserve the native esophagus have been successful with delayed primary anastomosis and tension-based esophageal growth induction processes. Esophageal replacement is necessary in a minority of cases, with the conduit of choice and patient outcomes largely dependent on institutional expertise. Given the complexity of this patient population with significant morbidity, treatment and long-term follow-up are best done in multidisciplinary esophageal and airway treatment centers. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Dark-bright gap solitons in coupled-mode one-dimensional saturable waveguide arrays

    SciTech Connect

    Dong Rong; Rueter, Christian E.; Kip, Detlef; Cuevas, Jesus; Kevrekidis, Panayotis G.; Song Daohong; Xu Jingjun

    2011-06-15

    In the present work, we consider the dynamics of dark solitons as one mode of a defocusing photorefractive lattice coupled with bright solitons as a second mode of the lattice. Our investigation is motivated by an experiment that illustrates that such coupled states can exist with both components in the first gap of the linear band spectrum. This finding is further extended by the examination of different possibilities from a theoretical perspective, such as symbiotic ones where the bright component is supported by states of the dark component in the first or second gap, or nonsymbiotic ones where the bright soliton is also a first-gap state coupled to a first or second gap state of the dark component. While the obtained states are generally unstable, these instabilities typically bear fairly small growth rates, which enable their observation for experimentally relevant propagation distances.

  14. Millimeter-Gap Magnetically Insulated Transmission Line Power Flow Experiments

    SciTech Connect

    Hutsel, Brian Thomas; Stoltzfus, Brian S.; Fowler, William E.; LeChien, Keith R.; Mazarakis, Michael G.; Moore, James K.; Mulville, Thomas D.; Savage, Mark E.; Stygar, William A.; McKenney, John L.; Jones, Peter A.; MacRunnels, Diego J.; Long, Finis W.; Porter, John L.

    2014-09-01

    An experiment platform has been designed to study vacuum power flow in magnetically insulated transmission lines (MITLs). The platform was driven by the 400-GW Mykonos-V accelerator. The experiments conducted quantify the current loss in a millimeter-gap MITL with respect to vacuum conditions in the MITL for two different gap distances, 1.0 and 1.3 mm. The current loss for each gap was measured for three different vacuum pump down times. As a ride along experiment, multiple shots were conducted with each set of hardware to determine if there was a conditioning effect to increase current delivery on subsequent shots. The experiment results revealed large differences in performance for the 1.0 and 1.3 mm gaps. The 1.0 mm gap resulted in current loss of 40%-60% of peak current. The 1.3 mm gap resulted in current losses of less than 5% of peak current. Classical MITL models that neglect plasma expansion predict that there should be zero current loss, after magnetic insulation is established, for both of these gaps. The experiments result s indicate that the vacuum pressure or pump down time did not have a significant effect on the measured current loss at vacuum pressures between 1e-4 and 1e-5 Torr. Additionally, there was not repeatable evidence of a conditioning effect that reduced current loss for subsequent full-energy shots on a given set of hardware. It should be noted that the experiments conducted likely did not have large loss contributions due to ion emission from the anode due to the relatively small current densi-ties (25-40 kA/cm) in the MITL that limited the anode temperature rise due to ohmic heating. The results and conclusions from these experiments may have limited applicability to MITLs of high current density (>400 kA/cm) used in the convolute and load region of the Z which experience temperature increases of >400° C and generate ion emission from anode surfaces.

  15. Bhattacharyya distance based video scene change detection

    NASA Astrophysics Data System (ADS)

    Shen, Bichuan; Chen, C. H.

    2009-10-01

    This paper studies statistics based scene change detection in the video streaming scenario, and three scene feature metrics including histogram distance, chi-square distance, and Bhattacharyya distance have been investigated. With the unique characteristics of triangular inequality and non-singularity, Bhattacharyya distance has been proposed as a viable scene change metrics. It outperforms much better than the other two in that it calculates and maximizes the feature vector distance between multi-modal clusters in a hyper-sphere space. The experiments are conducted and the precision recall statistics are compared, and the results support our analysis.

  16. From language identification to language distance

    NASA Astrophysics Data System (ADS)

    Gamallo, Pablo; Pichel, José Ramom; Alegria, Iñaki

    2017-10-01

    In this paper, we define two quantitative distances to measure how far apart two languages are. The distance measure that we have identified as more accurate is based on the perplexity of n-gram models extracted from text corpora. An experiment to compare forty-four European languages has been performed. For this purpose, we computed the distances for all the possible language pairs and built a network whose nodes are languages and edges are distances. The network we have built on the basis of linguistic distances represents the current map of similarities and divergences among the main languages of Europe.

  17. The minimum distance approach to classification

    NASA Technical Reports Server (NTRS)

    Wacker, A. G.; Landgrebe, D. A.

    1971-01-01

    The work to advance the state-of-the-art of miminum distance classification is reportd. This is accomplished through a combination of theoretical and comprehensive experimental investigations based on multispectral scanner data. A survey of the literature for suitable distance measures was conducted and the results of this survey are presented. It is shown that minimum distance classification, using density estimators and Kullback-Leibler numbers as the distance measure, is equivalent to a form of maximum likelihood sample classification. It is also shown that for the parametric case, minimum distance classification is equivalent to nearest neighbor classification in the parameter space.

  18. Laser Doppler distance sensor using phase evaluation.

    PubMed

    Günther, P; Pfister, T; Büttner, L; Czarske, J

    2009-02-16

    This paper presents a novel optical sensor which allows simultaneous measurements of axial position and tangential velocity of moving solid state objects. An extended laser Doppler velocimeter setup is used with two slightly tilted interference fringe systems. The distance to a solid state surface can be determined via a phase evaluation. The phase laser Doppler distance sensor offers a distance resolution of 150 nm and a total position uncertainty below 1 microm. Compared to conventional measurement techniques, such as triangulation, the distance resolution is independent of the lateral surface velocity. This advantage enables precise distance and shape measurements of fast rotating surfaces.

  19. KINEMATIC DISTANCES OF GALACTIC PLANETARY NEBULAE

    SciTech Connect

    Yang, A. Y.; Tian, W. W.; Zhu, H.; Wu, D.; Leahy, D. A. E-mail: ayyang@bao.ac.cn

    2016-03-15

    We construct H i absorption spectra for 18 planetary nebulae (PNs) and their background sources using data from the International Galactic Plane Survey. We estimate the kinematic distances of these PNs, among which 15 objects’ kinematic distances are obtained for the first time. The distance uncertainties of 13 PNs range from 10% to 50%, which is a significant improvement with uncertainties of a factor of two or three smaller than most previous distance measurements. We confirm that PN G030.2−00.1 is not a PN because of its large distance found here.

  20. Galaxy Cluster Smashes Distance Record

    NASA Astrophysics Data System (ADS)

    2009-10-01

    he most distant galaxy cluster yet has been discovered by combining data from NASA's Chandra X-ray Observatory and optical and infrared telescopes. The cluster is located about 10.2 billion light years away, and is observed as it was when the Universe was only about a quarter of its present age. The galaxy cluster, known as JKCS041, beats the previous record holder by about a billion light years. Galaxy clusters are the largest gravitationally bound objects in the Universe. Finding such a large structure at this very early epoch can reveal important information about how the Universe evolved at this crucial stage. JKCS041 is found at the cusp of when scientists think galaxy clusters can exist in the early Universe based on how long it should take for them to assemble. Therefore, studying its characteristics - such as composition, mass, and temperature - will reveal more about how the Universe took shape. "This object is close to the distance limit expected for a galaxy cluster," said Stefano Andreon of the National Institute for Astrophysics (INAF) in Milan, Italy. "We don't think gravity can work fast enough to make galaxy clusters much earlier." Distant galaxy clusters are often detected first with optical and infrared observations that reveal their component galaxies dominated by old, red stars. JKCS041 was originally detected in 2006 in a survey from the United Kingdom Infrared Telescope (UKIRT). The distance to the cluster was then determined from optical and infrared observations from UKIRT, the Canada-France-Hawaii telescope in Hawaii and NASA's Spitzer Space Telescope. Infrared observations are important because the optical light from the galaxies at large distances is shifted into infrared wavelengths because of the expansion of the universe. The Chandra data were the final - but crucial - piece of evidence as they showed that JKCS041 was, indeed, a genuine galaxy cluster. The extended X-ray emission seen by Chandra shows that hot gas has been detected