Sample records for differential distance ladder

  1. The first three rungs of the cosmological distance ladder (United States)

    Krisciunas, Kevin; DeBenedictis, Erika; Steeger, Jeremy; Bischoff-Kim, Agnes; Tabak, Gil; Pasricha, Kanika


    It is straightforward to determine the size of the Earth and the distance to the Moon without using a telescope. The methods have been known since the third century BCE. However, few astronomers have done this measurement from data they have taken. We use a gnomon to determine the latitude and longitude of South Bend, Indiana, and College Station, Texas, and determine the value of the radius of the Earth to be Rearth=6290 km, only 1.4% smaller than the known value. We use the method of Aristarchus and the size of the Earth's shadow during the lunar eclipse of June 15, 2011 to estimate the distance to the Moon to be 62.3Rearth, 3.3% greater than the known mean value. We use measurements of the angular motion of the Moon against the background stars over the course of two nights, using a simple cross staff device, to estimate the Moon's distance at perigee and apogee. We use simultaneous observations of asteroid 1996 HW1 obtained with small telescopes in Socorro, New Mexico, and Ojai, California, to obtain a value of the Astronomical Unit of (1.59+/-0.19)×108 km, about 6% too large. The data and methods presented here can easily become part of an introductory astronomy laboratory class.

  2. Utilization of the fish ladder at the Engenheiro Sergio Motta Dam, Brazil, by long distance migrating potamodromous species

    Directory of Open Access Journals (Sweden)

    Sérgio Makrakis

    Full Text Available Utilization of the fish ladder installed at the Engenheiro Sergio Motta Dam (also known as Porto Primavera on the Paraná River, Southern Brazil, by long-distance migrating potamodromous species (sampling Protocol I, and ascending and descending movements (Protocol II were evaluated. Three pools along the fish ladder (designated as lower, middle, and upper were sampled monthly between December, 2004 and March, 2005 to determine the abundance of species in the ladder. The ascending and descending movements of the species in the ladder were also analyzed in the same period. In the samples for both protocols, 37 species representing 17 families and 5 orders (Characiformes, Siluriformes, Perciformes, Gymnotiformes, and Myliobatiformes were recorded. Characiformes were represented by 21 species. Long- distance migratory species (11 species predominated in the ladder (60% of the total number of individuals, with high abundance of Rhinelepis aspera (5645 individuals. For protocol I, mean abundance varied greatly among the months and pools, with lowest values in December and March for all pools, and highest in January for the lower pool due to high capture of R. aspera. Fish abundance declined from the lower to the upper pool, especially for R. aspera and Rhaphiodon vulpinus. For Protocol II, 17 species were recorded ascending the ladder, where Astyanax altiparanae and Leporinus friderici were the most abundant species (684 and 111 individuals, respectively. However, 18 species showed descending movements, with high captures of Metynnis maculatus and A. altiparanae (339 and 319 individuals, respectively. Twelve species (52% moved in both directions, and among the seven migratory species sampled, four were recorded ascending and descending, and three species only ascending the ladder. The fish ladder appears to selectively favor species with high swimming capabilities. A discussion is presented on the requirements for future research on attraction to the

  3. Insensitivity of The Distance Ladder Hubble Constant Determination to Cepheid Calibration Modeling Choices (United States)

    Follin, B.; Knox, L.


    Recent determination of the Hubble constant via Cepheid-calibrated supernovae by Riess et al. (2016) (R16) find ˜3σ tension with inferences based on cosmic microwave background temperature and polarization measurements from Planck. This tension could be an indication of inadequacies in the concordance ΛCDM model. Here we investigate the possibility that the discrepancy could instead be due to systematic bias or uncertainty in the Cepheid calibration step of the distance ladder measurement by R16. We consider variations in total-to-selective extinction of Cepheid flux as a function of line-of-sight, hidden structure in the period-luminosity relationship, and potentially different intrinsic colour distributions of Cepheids as a function of host galaxy. Considering all potential sources of error, our final determination of H0 = 73.3 ± 1.7 km/s/Mpc (not including systematic errors from the treatment of geometric distances or Type Ia Supernovae) shows remarkable robustness and agreement with R16. We conclude systematics from the modelling of Cepheid photometry, including Cepheid selection criteria, cannot explain the observed tension between Cepheid-variable and CMB-based inferences of the Hubble constant. Considering a `model-independent' approach to relating Cepheids in galaxies with known distances to Cepheids in galaxies hosting a Type Ia supernova and finding agreement with the R16 result, we conclude no generalization of the model relating anchor and host Cepheid magnitude measurements can introduce significant bias in the H0 inference.

  4. Ladder Safety Live #12985

    Energy Technology Data Exchange (ETDEWEB)

    Chochoms, Michael [Los Alamos National Laboratory


    This course presents information for working safely with portable ladders: specifically, stepladders, extensions ladders, and their derivations. Additionally, this course provides limited information on the safe use of stepstools and fixed ladders. The skills, techniques, and good practices needed for selecting, inspecting, setting up and securing, and using ladders are presented in this course.

  5. Ladder attachment platform (United States)

    Swygert,; Richard, W [Springfield, SC


    A ladder attachment platform is provided that includes a base for attachment to a ladder that has first and second side rails and a plurality of rungs that extend between in a lateral direction. Also included is a user platform for having a user stand thereon that is carried by the base. The user platform may be positioned with respect to the ladder so that it is not located between a first plane that extends through the first side rail and is perpendicular to the lateral direction and a second plane that extends through the second side rail and is perpendicular to the lateral direction.

  6. Boat boarding ladder placement (United States)


    Presented in three volumes; 'Boat Boarding Ladder Placement,' which explores safety considerations including potential for human contact with a rotating propeller; 'Boat Handhold Placement,' which explores essential principles and methods of fall con...

  7. 29 CFR 1917.119 - Portable ladders. (United States)


    ... Requirements for Portable Reinforced Plastic Ladders (d) Standards for job-made portable ladders. Job-made... usage. (1) Ladders made by fastening rungs or devices across a single rail are prohibited. (2) Ladders...

  8. The latrine ownership ladder

    DEFF Research Database (Denmark)

    Obeng, Peter Appiah; Keraita, Bernard; Oduro-Kwarteng, Sampson


    Purpose – The purpose of this paper is to present the latrine ownership ladder as a conceptual policy framework to enhance sanitation uptake in low-income peri-urban areas. Design/methodology/approach – The paper draws from literature and a case study in a Ghanaian peri-urban community to highlig...

  9. Ladder Variational Autoencoder

    DEFF Research Database (Denmark)

    Sønderby, Casper Kaae; Raiko, Tapani; Maaløe, Lars


    Variational autoencoders are powerful models for unsupervised learning. However deep models with several layers of dependent stochastic variables are difficult to train which limits the improvements obtained using these highly expressive models. We propose a new inference model, the Ladder...... Variational Autoencoder, that recursively corrects the generative distribution by a data dependent approximate likelihood in a process resembling the recently proposed Ladder Network. We show that this model provides state of the art predictive log-likelihood and tighter log-likelihood lower bound compared...... to the purely bottom-up inference in layered Variational Autoencoders and other generative models. We provide a detailed analysis of the learned hierarchical latent representation and show that our new inference model is qualitatively different and utilizes a deeper more distributed hierarchy of latent...

  10. Ladder variational autoencoders

    DEFF Research Database (Denmark)

    Sønderby, Casper Kaae; Raiko, Tapani; Maaløe, Lars


    Variational autoencoders are powerful models for unsupervised learning. However deep models with several layers of dependent stochastic variables are difficult to train which limits the improvements obtained using these highly expressive models. We propose a new inference model, the Ladder...... Variational Autoencoder, that recursively corrects the generative distribution by a data dependent approximate likelihood in a process resembling the recently proposed Ladder Network. We show that this model provides state of the art predictive log-likelihood and tighter log-likelihood lower bound compared...... to the purely bottom-up inference in layered Variational Autoencoders and other generative models. We provide a detailed analysis of the learned hierarchical latent representation and show that our new inference model is qualitatively different and utilizes a deeper more distributed hierarchy of latent...

  11. Population differentiation at a regional scale in spadefoot toads: contributions of distance and divergent selective environments (United States)

    Rice, Amber M.; McQuillan, Michael A.


    Abstract The causes of population differentiation can provide insight into the origins of early barriers to gene flow. Two key drivers of population differentiation are geographic distance and local adaptation to divergent selective environments. When reproductive isolation arises because some populations of a species are under selection to avoid hybridization while others are not, population differentiation and even speciation can result. Spadefoot toad populations Spea multiplicata that are sympatric with a congener have undergone reinforcement. This reinforcement has resulted not only in increased reproductive isolation from the congener, but also in the evolution of reproductive isolation from nearby and distant conspecific allopatric populations. We used multiple approaches to evaluate the contributions of geographic distance and divergent selective environments to population structure across this regional scale in S. multiplicata, based on genotypes from six nuclear microsatellite markers. We compared groups of populations varying in both geographic location and in the presence of a congener. Hierarchical F-statistics and results from cluster analyses and discriminant analyses of principal components all indicate that geographic distance is the stronger contributor to genetic differentiation among S. multiplicata populations at a regional scale. However, we found evidence that adaptation to divergent selective environments also contributes to population structure. Our findings highlight how variation in the balance of evolutionary forces acting across a species’ range can lead to variation in the relative contributions of geographic distance and local adaptation to population differentiation across different spatial scales. PMID:29491906

  12. Protection Coordination in Electrical Substation Part-2 Unit Protections (Differential and Distance Protection)


    TÜR, Mehmet Rida; Shobole, Abdulfetah; Baysal, Mustafa; Wadi, Mohammed


    Power systemsmust be protected against faults to ensure quality and reliable generation,transmission and distribution of power systems. Power system protection is providedby the protection relays. This paper is the second part of the ProtectionCoordination study for the Siddik Kardesler Substation. The protection fortransmission lines, transformer, bus bars and customer feeders is provided byovercurrent protection, differential and distance protection schemes. In thispaper, issues related wit...

  13. Teaching differential diagnosis to nurse practitioner students in a distance program. (United States)

    Colella, Christine L; Beery, Theresa A


    An interactive case study (ICS) is a novel way to enhance the teaching of differential diagnosis to distance learning nurse practitioner students. Distance education renders the use of many teaching strategies commonly used with face-to-face students difficult, if not impossible. To meet this new pedagogical dilemma and to provide excellence in education, the ICS was developed. Kolb's theory of experiential learning supported efforts to follow the utilization of the ICS. This study sought to determine whether learning outcomes for the distance learning students were equivalent to those of on-campus students who engaged in a live-patient encounter. Accuracy of differential diagnosis lists generated by onsite and online students was compared. Equivalency testing assessed clinical, rather than only statistical, significance in data from 291 students. The ICS responses from the distance learning and onsite students differed by 4.9%, which was within the a priori equivalence estimate of 10%. Narrative data supported the findings. Copyright 2014, SLACK Incorporated.

  14. Microfluidic serial dilution ladder. (United States)

    Ahrar, Siavash; Hwang, Michelle; Duncan, Philip N; Hui, Elliot E


    Serial dilution is a fundamental procedure that is common to a large number of laboratory protocols. Automation of serial dilution is thus a valuable component for lab-on-a-chip systems. While a handful of different microfluidic strategies for serial dilution have been reported, approaches based on continuous flow mixing inherently consume larger amounts of sample volume and chip real estate. We employ valve-driven circulatory mixing to address these issues and also introduce a novel device structure to store each stage of the dilution process. The dilution strategy is based on sequentially mixing the rungs of a ladder structure. We demonstrate a 7-stage series of 1 : 1 dilutions with R(2) equal to 0.995 in an active device area of 1 cm(2).

  15. 29 CFR 1926.1053 - Ladders. (United States)


    ... plastic ladder shall sustain at least 3.3 times the maximum intended load. The ability of a ladder to... that each extra-heavy-duty type 1A metal or plastic ladders shall sustain at least 3.3 times the... from anticipated usage of the ladder, shall also be included), plus anticipated loads caused by ice...

  16. 29 CFR 1917.118 - Fixed ladders. (United States)


    ... and fastened to one or both of the ladder's side rails or to another structure. (2) Fixed ladder means... walls of the well. (c) Defects. (1) Ladders with broken, split or missing rungs, steps or rails, broken welds or connections, corrosion or wastage or other defect which may affect safe use shall be removed...

  17. De optimale sportafstand voor de ladder van de glazenwasser

    NARCIS (Netherlands)

    Reijneveld, C.N.; Looze, M.P. de; Hoozemans, M.J.M.; Grinten, M.P. van der; Korte, E.M. de; Kingma, I.


    Voor de glazenwasser die werkt met staande ladder, is een goede ladder zeer belangrijk. Hij loopt en werkt op en verplaatst de ladder veelvuldig. Er is veel discussie over ladders en de optimale sportafstand bij staande ladders. De meeste glazenwassers geven de voorkeur aan een sportafstand van 35

  18. Measuring a Country's Product Ladder and Technology Level based on Trade Flow

    Directory of Open Access Journals (Sweden)

    Jong-il Kim


    Full Text Available This study tries to quantify the technology level of products based on the concept of product ladder. While many studies on country technology competitiveness use the aggregate indices such as total factor productivity and revealed comparative advantage, this study estimates the ranking of about 2000 products in product ladder by using SITC 5 digit level export data. Based on the product ladder, this study measures the country and industry ranking and explores the characteristics of the ranking. It provides the international comparison of inter-industry and intra-industry ranking differences in product ladder. The statistical relationships between the ranking in product ladder and the determinants of technology level such as R&D and physical capital investment and wage, confirms that the measured ranking in product ladder could be regarded as an indirect indicator of technology level. The product ladder is applied to the estimation of production function to see the effect of the product differentiation on labor productivity.

  19. Understanding the Behaviour of Infinite Ladder Circuits (United States)

    Ucak, C.; Yegin, K.


    Infinite ladder circuits are often encountered in undergraduate electrical engineering and physics curricula when dealing with series and parallel combination of impedances, as a part of filter design or wave propagation on transmission lines. The input impedance of such infinite ladder circuits is derived by assuming that the input impedance does…

  20. Laddering em pesquisa de marketing

    Directory of Open Access Journals (Sweden)

    Tânia Modesto Veludo-de-Oliveira

    Full Text Available O artigo discute a técnica de pesquisa laddering em marketing, considerando a proposta de renovação de conhecimentos sobre metodologia na área. Para isso investiga diversos estudos, artigos e pesquisas que tratam do assunto em nível nacional e internacional. O conceito de cadeias meios-fins é abordado pela estrutura teórica que fundamenta a técnica, ligando atributos, conseqüências percebidas do consumo e valores pessoais relativos a um produto. O artigo segue com a explicação dos procedimentos de campo, como a entrevista e a análise dos dados. A laddering é um instrumento de pesquisa qualitativa bastante útil e poderoso, mas ainda pouco utilizado tanto por acadêmicos como por profissionais de mercado, no Brasil, provavelmente por desconhecimento e pouca divulgação. Cabe, portanto, uma maior disseminação de seu uso.

  1. Available friction of ladder shoes and slip potential for climbing on a straight ladder. (United States)

    Chang, Wen-Ruey; Chang, Chien-Chi; Matz, Simon


    Straight ladder accidents are a major safety problem. As a leading cause of injuries involving straight ladders, slips at the ladder base occur when the required friction exceeds the available friction at the ladder shoe and floor interface. The objectives of this experiment were to measure the available friction at the base of a portable straight ladder in contact with a floor and to estimate the slip potential of the ladder. The results of friction measurements indicated that the measured friction coefficient on the oily surfaces differed among the six commercially available ladder shoes evaluated. A statistical model was used to compare the available friction results from the current study with the friction requirements under different climbing conditions from a previous study based on their stochastic distributions to estimate the slip potential at the base of the ladder. The results showed that different climbing conditions used in the previous study could be supported by available friction on dry surfaces. However, when the ladder was put onto oily surfaces, resulting in a significant reduction in the available friction due to contamination, slip potential was significantly increased.

  2. Critical Thinking via the Abstraction Ladder. (United States)

    Seabury, Marcia Bundy


    Discusses strategies (based on S. I. Hayakawa's abstraction ladder) to encourage connected thinking in student writing. Describes a recent cross-disciplinary workshop seeking to improve student essay writing and evaluation. (KEH)

  3. Mass ladder operators from spacetime conformal symmetry (United States)

    Cardoso, Vitor; Houri, Tsuyoshi; Kimura, Masashi


    Ladder operators can be useful constructs, allowing for unique insight and intuition. In fact, they have played a special role in the development of quantum mechanics and field theory. Here, we introduce a novel type of ladder operators, which map a scalar field onto another massive scalar field. We construct such operators, in arbitrary dimensions, from closed conformal Killing vector fields, eigenvectors of the Ricci tensor. As an example, we explicitly construct these objects in anti-de Sitter (A d S ) spacetime and show that they exist for masses above the Breitenlohner-Freedman bound. Starting from a regular seed solution of the massive Klein-Gordon equation, mass ladder operators in AdS allow one to build a variety of regular solutions with varying boundary condition at spatial infinity. We also discuss mass ladder operator in the context of spherical harmonics, and the relation between supersymmetric quantum mechanics and so-called Aretakis constants in an extremal black hole.

  4. Towards automatic verification of ladder logic programs


    Zoubek , Bohumir; Roussel , Jean-Marc; Kwiatkowska , Martha


    International audience; Control system programs are usually validated by testing prior to their deployment. Unfortunately, testing is not exhaustive and therefore it is possible that a program which passed all the required tests still contains errors. In this paper we apply techniques of automatic verification to a control program written in ladder logic. A model is constructed mechanically from the ladder logic program and subjected to automatic verification against requirements that include...

  5. The transient ladder synchronization of chaotic systems

    International Nuclear Information System (INIS)

    Chen, H.-K.; Sheu, L.-J.


    A new type for chaotically synchronizing systems, transient ladder chaos synchronization, is proposed in this Letter. For some physical systems, chaotic synchronization is possible in only some of the variables. It is shown that, for the non-synchronizing variable, synchronization up to a constant difference for t 1 = 2 is possible. The transient ladder chaos synchronization and anti-synchronization are illustrated by using two identical chaotic Froude pendulums. Numerical simulations are shown for demonstration

  6. Product Differentiation and Brand Competition in the Italian Breakfast Cereal Market: a Distance Metric Approach

    Directory of Open Access Journals (Sweden)

    Paolo Sckokai


    Full Text Available This article employs a nation-wide sample of supermarket scanner data to study product and brand competition in the Italian breakfast cereal market. A modified Almost Ideal Demand System (AIDS, that includes Distance Metrics (DMs as proposed by Pinkse, Slade and Brett (2002, is estimated to study demand responses, substitution patterns, own-price and cross-price elasticities. Estimation results provide evidence of some degree of brand loyalty, while consumers do not seem loyal to the product type. Elasticity estimates point out the presence of patterns of substitution within products sharing the same brand and similar nutritional characteristics.

  7. Keeping a healthy distance: Self-differentiation and perceived health among ex-prisoners-of-war's wives. (United States)

    Lahav, Yael; Stein, Jacob Y; Solomon, Zahava


    War captivity may affect spouses of former-prisoners-of-war (ex-POWs) in many ways, including posttraumatic stress symptoms (PTSS) and somatic difficulties manifested in negative perceived health. This is generally known as secondary traumatization. Theory suggests that development of secondary traumatization occurs through the relationship with the primary trauma survivor Figley (1986) , thus implying that the ability to keep balanced emotional distance in the relationship may play a pivotal role. Notwithstanding, the contribution of self-differentiation to secondary somatic disturbances remains largely uninvestigated. The current study fills this gap. Ex-POWs' wives (n=143) and control former-combatants' wives (n=102), were assessed prospectively 30 (T1) and 38 (T2) years after the 1973 Yom Kippur War. Self-differentiation and PTSS were assessed at both time-points, while perceived health measures were assessed at T2. Wives of ex-POWs endorsed higher PTSS, lower self-differentiation and negative perceived health, compared to control wives. Indirect exposure to war captivity was related to low self-differentiation and elevated PTSS, which predicted negative perceived health. Furthermore, self-differentiation characterized by fusion-with-others fully mediated the relation between indirect exposure to war captivity and perceived health, beyond the effects of PTSS as a mechanism. Results suggest that tendencies towards fusion-with-others within the marital relationship, act as a risk factor not only for psychological distress but also for somatic distress among secondary trauma survivors. Hence, clinical interventions may seek to improve indirect trauma survivor's self-differentiation capacities, thus potentially facilitating the prevention of secondary somatic distress. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Doped spin ladders under magnetic field

    International Nuclear Information System (INIS)

    Roux, G.


    This thesis deals with the physics of doped two-leg ladders which are a quasi one-dimensional and unconventional superconductor. We particularly focus on the properties under magnetic field. Models for strongly correlated electrons on ladders are studied using exact diagonalization and density-matrix renormalization group (DMRG). Results are also enlightened by using the bosonization technique. Taking into account a ring exchange it highlights the relation between the pairing of holes and the spin gap. Its influence on the dynamics of the magnetic fluctuations is also tackled. Afterwards, these excitations are probed by the magnetic field by coupling it to the spin degree of freedom of the electrons through Zeeman effect. We show the existence of doping-dependent magnetization plateaus and also the presence of an inhomogeneous superconducting phase (FFLO phase) associated with an exceeding of the Pauli limit. When a flux passes through the ladder, the magnetic field couples to the charge degree of freedom of the electrons via orbital effect. The diamagnetic response of the doped ladder probes the commensurate phases of the t-J model at low J/t. Algebraic transverse current fluctuations are also found once the field is turned on. Lastly, we report numerical evidences of a molecular superfluid phase in the 3/2-spin attractive Hubbard model: at a density low enough, bound states of four fermions, called quartets, acquire dominant superfluid fluctuations. The observed competition between the superfluid and density fluctuations is connected to the physics of doped ladders. (author)

  9. Computing differential refraction at all heliolatitudes and zenithal distances: a historical perspective (United States)

    Sigismondi, C.; Boscardin, S.


    Ptolemy (about 150 AC) modeled atmospheric refraction influencing Al Farghani (831), Alhazen (1020), Sacrobosco (1256) and Witelo (1278): the Sun was supposed bigger at horizon like a coin appears under water in a curved bottle. The correct work of Ibn Sahl (984) remained forgotten. Tycho measured the refraction on the 1572 supernova at various altitudes. Harriot, Kepler, Snell and Descartes found independently the refraction law after 1600. A modern formulation of vertical (0.5" zenithal to 35' at horizon) and horizontal (0.5" at all altitudes) differential refraction of solar diameter appears in Du Séjour (1786). Laplace's formula (1805) computes the vertical deformation of the solar disk, while the horizontal reduction of 0.5" is proportional to the chord's length. Dicke (1967) measured the solar oblateness to determine dynamical constraints to alternative theories of General Relativity. The Astrolabe of Rio de Janeiro measured in 1998-2009 the solar diameter at all heliolatitudes, by timing solar transits across fixed altitude circles: an equatorial excess larger than RHESSI (2008) and SDS (1992-2011) data remains after refraction's corrections. Meridian transits series measured at Rome Campidoglio (1877-1937) and Greenwich (1850-1940) behave as Rio data: the scatters between annual averages were larger than statistical dispersions of each value (Gething, 1955). Anomalous refractions measured with Rio Heliometer (2013) are low frequency seeing (0.01 Hz) acting to scales of the solar diameter (32'): they affect transits measurements with random perturbations hundreds times larger than the expected values calculated from the timing accuracy. These perturbations enlarge the differences between averages values binned either in time or heliolatitude: they are larger than statistical dispersions, suggesting a wider binning. The ``adiabatic" approach of Rio Heliometer with high frequency measurements ``freezes" the slow seeing image motion component.

  10. 29 CFR 1910.26 - Portable metal ladders. (United States)


    ... and taken out of service until repaired by either maintenance department or the manufacturer. (3) Use... are designed as a one-man working ladder based on a 200-pound load. (iii) The ladder base section must...

  11. Magnetic susceptibilities of integrable quantum ladders

    International Nuclear Information System (INIS)

    Park, Soo A; Lee, K.


    As an extension of previous studies, we consider the magnetic susceptibilities of a coupled spin chain model at low temperature and of a more realistic model at low temperature and of a more realistic model having a t-J ladder structure at zero temperature. The magnetic susceptibilities for both models are obtained numerically when the coupling constant is greater than its critical value. In this region, the ladders behave as a single chain for H c and as two independent chains for H>H c , showing a divergence at H c . This divergence is expected to smear out at a finite temperature

  12. The Static Ladder Problem with Two Sources of Friction (United States)

    Bennett, Jonathan; Mauney, Alex


    The problem of a ladder leaning against a wall in static equilibrium is a classic example encountered in introductory mechanics texts. Most discussions of this problem assume that the static frictional force between the ladder and wall can be ignored. A few authors consider the case where the static friction coefficients between ladder/wall…

  13. 46 CFR 116.438 - Stairtowers, stairways, ladders, and elevators. (United States)


    ... 46 Shipping 4 2010-10-01 2010-10-01 false Stairtowers, stairways, ladders, and elevators. 116.438... AND ARRANGEMENT Fire Protection § 116.438 Stairtowers, stairways, ladders, and elevators. (a) A vessel... the requirements for stairways, ladders, and elevators in § 72.05-20 of this chapter. (b) Materials...

  14. 46 CFR 72.05-20 - Stairways, ladders, and elevators. (United States)


    ... 46 Shipping 3 2010-10-01 2010-10-01 false Stairways, ladders, and elevators. 72.05-20 Section 72... CONSTRUCTION AND ARRANGEMENT Structural Fire Protection § 72.05-20 Stairways, ladders, and elevators. (a)(1..., ladders, and elevators within main machinery spaces or cargo holds are not covered by the general...

  15. Quantifying Ladder Fuels: A New Approach Using LiDAR (United States)

    Heather Kramer; Brandon Collins; Maggi Kelly; Scott Stephens


    We investigated the relationship between LiDAR and ladder fuels in the northern Sierra Nevada, California USA. Ladder fuels are often targeted in hazardous fuel reduction treatments due to their role in propagating fire from the forest floor to tree crowns. Despite their importance, ladder fuels are difficult to quantify. One common approach is to calculate canopy base...

  16. Hadron structure in the ladder model

    Energy Technology Data Exchange (ETDEWEB)

    Soper, D.E.


    The (flavor non-singlet) Green's function to find a far-off-shell quark in a hadron is obtained in the renormalization group improved ladder model for QCD in the space-like axial gauge. Particular attention is paid to the role of the singularity in the gluon propagator. 4 figures.

  17. 29 CFR 1915.72 - Ladders. (United States)


    ... nailed to each rail with five 10d common wire nails or fastened with through bolts or other fasteners of... split side rails, or other faulty or defective construction is prohibited. When ladders with such... bolted to each rail. The combined cross sectional area of the cleats shall be not less than the cross...

  18. Fermion-boson scattering in ladder approximation

    International Nuclear Information System (INIS)

    Jafarov, R.G.; Hadjiev, S.A.


    A method of calculation of forward scattering amplitude for fermions and scalar bosons with exchanging of scalar particle is suggested. The Bethe-Salpeter ladder equation for the imaginary part of the amplitude is constructed and a solution in Regge asymptotical form is found and the corrections to the amplitude due to the exit from mass shell are calculated. (author). 8 refs

  19. Population subdivision in marine environments: the contributions of biogeography, geographical distance and discontinuous habitat to genetic differentiation in a blennioid fish, Axoclinus nigricaudus. (United States)

    Riginos, C; Nachman, M W


    The relative importance of factors that may promote genetic differentiation in marine organisms is largely unknown. Here, contributions to population structure from a biogeographic boundary, geographical distance and the distribution of suitable habitat were investigated in Axoclinus nigricaudus, a small subtidal rock-reef fish, throughout its range in the Gulf of California. A 408-bp fragment of the mitochondrial control region was sequenced from 105 individuals. Variation was significantly partitioned between 28 of 36 possible combinations of population pairs. Phylogenetic analyses, hierarchical analyses of variance and a modified Mantel test substantiated a major break between two putative biogeographic regions. This genetic discontinuity coincides with an abrupt change in ecological characteristics, including temperature and salinity, but does not coincide with known oceanographic circulation patterns or any known historic barriers. There was an overall relationship of increasing genetic distance with increasing geographical distance between population pairs, in a manner consistent with isolation-by-distance. A significant habitat-by-geographical-distance interaction term indicated that, for a given geographical distance, populations separated by discontinuous habitat (sand) are more distinct genetically than are populations separated by continuous habitat (rock). In addition, populations separated by deep open waters were more genetically distinct than populations separated by continuous habitat (rock). These results indicate that levels of genetic differentiation among populations of A. nigricaudus cannot be explained by a single factor, but are due to the combined influences of biogeography, geographical distance and availability of suitable habitat.

  20. Clinical ladder program implementation: a project guide. (United States)

    Ko, Yu Kyung; Yu, Soyoung


    This article describes the development of a clinical ladder program (CLP) implementation linked to a promotion system for nurses. The CLP task force developed criteria for each level of performance and a performance evaluation tool reflecting the self-motivation of the applicant for professional development. One year after implementation, the number of nurses taking graduate courses increased, and 7 nurses were promoted to nurse manager positions.

  1. Representing distance, consuming distance

    DEFF Research Database (Denmark)

    Larsen, Gunvor Riber

    are being consumed in the contemporary society, in the same way as places, media, cultures and status are being consumed (Urry 1995, Featherstone 2007). An exploration of distance and its representations through contemporary consumption theory could expose what role distance plays in forming......Title: Representing Distance, Consuming Distance Abstract: Distance is a condition for corporeal and virtual mobilities, for desired and actual travel, but yet it has received relatively little attention as a theoretical entity in its own right. Understandings of and assumptions about distance...

  2. A Career Ladder's Effect on Teacher Career and Work Attitudes. (United States)

    Hart, Ann Weaver


    A career ladder affecting the work structure and career opportunities of teachers was studied to determine effects on teacher attitudes. Responses of 389 elementary through high school teachers to career ladder work efforts, work of schools, peer supervision, and career growth opportunities and stability were affected by the design. (TJH)

  3. 5 CFR 335.104 - Eligibility for career ladder promotion. (United States)


    ... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Eligibility for career ladder promotion. 335.104 Section 335.104 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS PROMOTION AND INTERNAL PLACEMENT General Provisions § 335.104 Eligibility for career ladder...

  4. Ladders to Literacy. What Works Clearinghouse Intervention Report (United States)

    What Works Clearinghouse, 2013


    "Ladders to Literacy" is a supplemental early literacy curriculum composed of 60 activities designed to develop children's print/book awareness, metalinguistic awareness, and oral language skills. The "Ladders to Literacy" activities can be implemented in a variety of early childhood settings and adapted for children with…

  5. 29 CFR 1910.25 - Portable wood ladders. (United States)


    ... which dimensions are specified should not be used by more than one man at a time nor with ladder jacks... step spacing shall be employed which shall be not more than 12 inches. Steps shall be parallel and...) [Reserved] (x) Ladders shall be inspected frequently and those which have developed defects shall be...

  6. A balanced intervention ladder: promoting autonomy through public health action. (United States)

    Griffiths, P E; West, C


    The widely cited Nuffield Council on Bioethics 'Intervention Ladder' structurally embodies the assumption that personal autonomy is maximized by non-intervention. Consequently, the Intervention Ladder encourages an extreme 'negative liberty' view of autonomy. Yet there are several alternative accounts of autonomy that are both arguably superior as accounts of autonomy and better suited to the issues facing public health ethics. We propose to replace the one-sided ladder, which has any intervention coming at a cost to autonomy, with a two-sided 'Balanced Intervention Ladder,' where intervention can either enhance or diminish autonomy. We show that not only the alternative, richer accounts of autonomy but even Mill's classic version of negative liberty puts some interventions on the positive side of the ladder. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

  7. Selectivity of fish ladders: a bottleneck in Neotropical fish movement

    Directory of Open Access Journals (Sweden)

    Carlos Sérgio Agostinho

    Full Text Available Although dozens of fish ladders have been constructed at dams of Brazilian reservoirs, there are few studies evaluating their efficiency as a tool for the conservation of Neotropical ichthyofauna, especially for migratory species. Therefore, the present study evaluated the selectivity of the species that entered and ascended the fish ladder located next to Lajeado Dam (Luis Eduardo Magalhães Hydroelectric Power Plant on the Tocantins River. Samples were taken monthly from November, 2002 through October, 2003, in the resting pools of the ladder, using cast nets, and in the downstream stretch, using gillnets. The selectivity of the ladder in attracting fish was evaluated by comparing the occurrence, relative abundance, dominance and the congruence of abundance ranks of migratory and non-migratory species in the ladder and in the stretch of river immediately downstream. Species richness and fish abundance in the resting pools were used to evaluate selectivity along the ladder. The effects on selectivity by temporal variations in water level downriver and maximum flow velocity in the fish ladder were also analyzed. Out of the 130 species recorded downriver, 62.3% were caught in the ladder, and migratory species were clearly favored. However, more than 2/3 of the catch belonged to only three species (Rhaphiodon vulpinus, Psectrogaster amazonica and Oxydoras niger. Although the majority of the species that entered the ladder were able to reach its top, there was a sharp reduction in abundance of individuals towards the top. Temporal variations in the water level below the dam influenced richness and abundance of fish concentrated downstream and in the ladder, with lower values during periods of low water. In the ladder, a maximum flow velocity of 2.3 m/s, although also selective, proved to be more appropriate for fish ascension than a velocity of 2.8 m/s. It was concluded that the entry and ascension of the fish in the ladder were not congruent with

  8. The laddering method in service innovation research

    DEFF Research Database (Denmark)

    Grünbaum, Niels Nolsøe


    map of what is actually going on in the consumer’s mind when the consumer is buying and consuming specific goods. It is argued, in this chapter, that this understanding is indeed both interesting and relevant in service innovation. More specifically, realizations of consumers’ values will help...... to guide marketers to understand what to innovate, how to innovate, how to plan and efficiently communicate changes, how to sell the innovations in the market place and how to implement organizational changes that innovations might cause. Furthermore, the laddering methodology has been applied across many...... fields with good success and the premises for using the method and for analyzing obtained data, is rather well described. The latter (i.e. premises and data analysis) is often raised as central and critical points of qualitative research methodology when arguing for problems with validity and reliability...

  9. Analytic processing of distance. (United States)

    Dopkins, Stephen; Galyer, Darin


    How does a human observer extract from the distance between two frontal points the component corresponding to an axis of a rectangular reference frame? To find out we had participants classify pairs of small circles, varying on the horizontal and vertical axes of a computer screen, in terms of the horizontal distance between them. A response signal controlled response time. The error rate depended on the irrelevant vertical as well as the relevant horizontal distance between the test circles with the relevant distance effect being larger than the irrelevant distance effect. The results implied that the horizontal distance between the test circles was imperfectly extracted from the overall distance between them. The results supported an account, derived from the Exemplar Based Random Walk model (Nosofsky & Palmieri, 1997), under which distance classification is based on the overall distance between the test circles, with relevant distance being extracted from overall distance to the extent that the relevant and irrelevant axes are differentially weighted so as to reduce the contribution of irrelevant distance to overall distance. The results did not support an account, derived from the General Recognition Theory (Ashby & Maddox, 1994), under which distance classification is based on the relevant distance between the test circles, with the irrelevant distance effect arising because a test circle's perceived location on the relevant axis depends on its location on the irrelevant axis, and with relevant distance being extracted from overall distance to the extent that this dependency is absent. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. LOFT 3C cable tray and ladder seismic analysis

    Energy Technology Data Exchange (ETDEWEB)

    Mosby, W.R.


    The LOFT 3C cable tray and ladder were analyzed for LOCE and Safe Shutdown Earthquake (SSE) seismic loads by using equivalent static loads. Design changes were recommended to alleviate overstress conditions.

  11. Log-concavity of the genus polynomials of Ringel Ladders

    Directory of Open Access Journals (Sweden)

    Jonathan L Gross


    Full Text Available A Ringel ladder can be formed by a self-bar-amalgamation operation on a symmetric ladder, that is, by joining the root vertices on its end-rungs. The present authors have previously derived criteria under which linear chains of copies of one or more graphs have log-concave genus polyno- mials. Herein we establish Ringel ladders as the first significant non-linear infinite family of graphs known to have log-concave genus polynomials. We construct an algebraic representation of self-bar-amalgamation as a matrix operation, to be applied to a vector representation of the partitioned genus distribution of a symmetric ladder. Analysis of the resulting genus polynomial involves the use of Chebyshev polynomials. This paper continues our quest to affirm the quarter-century-old conjecture that all graphs have log-concave genus polynomials.

  12. Fish ladders: safe fish passage or hotspot for predation?

    Directory of Open Access Journals (Sweden)

    Angelo Antonio Agostinho

    Full Text Available Fish ladders are a strategy for conserving biodiversity, as they can provide connectivity between fragmented habitats and reduce predation on shoals that accumulate immediately below dams. Although the impact of predation downstream of reservoirs has been investigated, especially in juvenile salmonids during their downstream movements, nothing is known about predation on Neotropical fish in the attraction and containment areas commonly found in translocation facilities. This study analysed predation in a fish passage system at the Lajeado Dam on the Tocantins River in Brazil. The abundance, distribution, and the permanence (time spent of large predatory fish along the ladder, the injuries imposed by piranhas during passage and the presence of other vertebrate predators were investigated. From December 2002 to October 2003, sampling was conducted in four regions (downstream, along the ladder, in the forebay, and upstream of the reservoir using gillnets, cast nets and counts or visual observations. The captured fish were tagged with thread and beads, and any mutilations were registered. Fish, birds and dolphins were the main predator groups observed, with a predominance of the first two groups. The entrance to the ladder, in the downstream region, was the area with the highest number of large predators and was the only region with relevant non-fish vertebrates. The main predatory fish species were Rhaphiodon vulpinus, Hydrolycus armatus, and Serrasalmus rhombeus. Tagged individuals were detected predating along the ladder for up to 90 days. Mutilations caused by Serrasalmus attacks were noted in 36% of species and 4% of individuals at the top of the ladder. Our results suggested that the high density of fish in the restricted ladder environment, which is associated with injuries suffered along the ladder course and the presence of multiple predator groups with different predation strategies, transformed the fish corridor into a hotspot for

  13. Effects of ladder parameters on asymmetric patterns of force exertion during below-knee amputees climbing ladders. (United States)

    Li, Weidong; Li, Shiqi; Fu, Yan; Chen, Jacon


    Different from walking, ladder climbing requires four-limb coordination and more energy exertion for below-knee amputees (BKAs). We hypothesized that functional deficiency of a disabled limb shall be compensated by the other three intact limbs, showing an asymmetry pattern among limbs. Hand and foot forces of six below-knee amputees and six able-bodied people were collected. Hand, foot and hand/foot sum force variances between groups (non-BKA, intact side and prosthetic side) were carefully examined. Our hypothesis was validated that there is asymmetry between prosthetic and intact side. Results further showed that the ipsilateral hand of the prosthetic leg is stronger than the hand on the intact side, compensating weakness of the prosthetic leg. Effects of ladder rung separations and ladder slant on asymmetric force distribution of BKAs were evaluated, indicating that rung separation has a more significant interactive effect on hand/foot force of BKAs than ladder slant.

  14. The course “Virtual Learning Environment” and the teacher training: differentiated didactic strategies for a distance training

    Directory of Open Access Journals (Sweden)

    Oscar Massaru Fujita


    Full Text Available This article aims to describe the methodological process and the teaching strategies adopted in the course of Virtual Learning Environment (VLE offered by the State University of Londrina (UEL-PR. This course was offered through Distance Education (DE between August and December of 2014, with a workload of 60 hours, and was developed for graduation and postgraduation students, staff and teachers from differente areas of knowledge from this institution. The course aimed to promote reflections on the insertion of DTIC (Digital Technologies of Information and Communication in the school enviroment, provide theoritical support on DE and create teaching strategies for its development. The VLE course stands out for being the first course of University Extension offered by UEL destined specifically for DE and Teacher Education. The study had a qualitative approach of research-action type. The data was collected by observations, perceptions and especially by the testimonies of the participants. The methodology adopted in the course was the Active Learning Methodology and the teaching strategies based on the PBL (Problem Based Learning. The results, with regard to learning, development and exploitation of students, were considered satisfactory.

  15. Evaluation of a Multiplex PCR Assay (Bruce-ladder) for Molecular Typing of All Brucella Species, Including the Vaccine Strains▿ † (United States)

    López-Goñi, I.; García-Yoldi, D.; Marín, C. M.; de Miguel, M. J.; Muñoz, P. M.; Blasco, J. M.; Jacques, I.; Grayon, M.; Cloeckaert, A.; Ferreira, A. C.; Cardoso, R.; Corrêa de Sá, M. I.; Walravens, K.; Albert, D.; Garin-Bastuji, B.


    An evaluation of a multiplex PCR assay (Bruce-ladder) was performed in seven laboratories using 625 Brucella strains from different animal and geographical origins. This robust test can differentiate in a single step all of the classical Brucella species, including those found in marine mammals and the S19, RB51, and Rev.1 vaccine strains. PMID:18716225

  16. Nitration Study of Cyclic Ladder Polyphenylsilsesquioxane

    Directory of Open Access Journals (Sweden)

    LIANG Jia-xiang


    Full Text Available Several nitration reagents including fuming nitric acid, HNO3-H2SO4, KNO3-H2SO4, HNO3-KNO3, CH3COOH-KNO3, (CH3CO2O-HNO3 were used to nitrate cyclic ladder polyphenylsilsesquioxane (CL-PPSQ in different conditions in order to enhance the compatibility of the CL-PPSQ in polymers, the NO2-PPSQ was obtained. FTIR, element analysis, GPC, TGA and 1H NMR were used to characterize the structures of the nitrated products. The results show that the nitrating abilities of the fuming nitric acid, HNO3-H2SO4 and KNO3-H2SO4 are very strong. Many nitro groups can be linked with phenyl groups in CL-PPSQ, but with low molecular mass, fracture occurs in siloxane segment. However, the Mn of the product NO2-PPSQ sharply drops by 50% compared with that of CL-PPSQ, so the nitration reagents can break the cyclic structure of CL-PPSQ. The nitrating reagents of HNO3-KNO3 and CH3COOH-KNO3 have no nitration effects on CL-PPSQ. At last, NO2-CL-PPSQ was prepared using (CH3CO2O-HNO3 because of the moderate nitration process and ability. The cyclic structure of PPSQ is remained, although the number of —NO2 group is not too much. At the same time, the nitration mechanism using different nitration reagents was analyzed. A certain amount of NO2+, which is a kind of activator owning strong nitration ability, can be found in the fuming nitric acid and H2SO4-HNO3(KNO3 systems. As to the (CH3CO2O-HNO3 system, the main activator is CH3COONO2.

  17. PT-symmetric ladders with a scattering core

    Energy Technology Data Exchange (ETDEWEB)

    D' Ambroise, J. [Department of Mathematics, Amherst College, Amherst, MA 01002-5000 (United States); Lepri, S. [CNR – Consiglio Nazionale delle Ricerche, Istituto dei Sistemi Complessi, via Madonna del piano 10, I-50019 Sesto Fiorentino (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Firenze, via G. Sansone 1, I-50019 Sesto Fiorentino (Italy); Malomed, B.A. [Department of Physical Electronics, School of Electrical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv 69978 (Israel); Kevrekidis, P.G. [Department of Mathematics and Statistics, University of Massachusetts, Amherst, MA 01003-9305 (United States)


    We consider a PT-symmetric chain (ladder-shaped) system governed by the discrete nonlinear Schrödinger equation where the cubic nonlinearity is carried solely by two central “rungs” of the ladder. Two branches of scattering solutions for incident plane waves are found. We systematically construct these solutions, analyze their stability, and discuss non-reciprocity of the transmission associated with them. To relate the results to finite-size wavepacket dynamics, we also perform direct simulations of the evolution of the wavepackets, which confirm that the transmission is indeed asymmetric in this nonlinear system with the mutually balanced gain and loss. - Highlights: • We model a PT-symmetric ladder system with cubic nonlinearity on two central rungs. • We examine non-reciprocity and stability of incident plane waves. • Simulations of wavepackets confirm our results.

  18. A Review and Modern Approach to LC Ladder Synthesis

    Directory of Open Access Journals (Sweden)

    Alexander J. Casson


    Full Text Available Ultra low power circuits require robust and reliable operation despite the unavoidable use of low currents and the weak inversion transistor operation region. For analogue domain filtering doubly terminated LC ladder based filter topologies are thus highly desirable as they have very low sensitivities to component values: non-exact component values have a minimal effect on the realised transfer function. However, not all transfer functions are suitable for implementation via a LC ladder prototype, and even when the transfer function is suitable the synthesis procedure is not trivial. The modern circuit designer can thus benefit from an updated treatment of this synthesis procedure. This paper presents a methodology for the design of doubly terminated LC ladder structures making use of the symbolic maths engines in programs such as MATLAB and MAPLE. The methodology is explained through the detailed synthesis of an example 7th order bandpass filter transfer function for use in electroencephalogram (EEG analysis.

  19. Distance Learning

    National Research Council Canada - National Science Library

    Braddock, Joseph


    A study reviewing the existing Army Distance Learning Plan (ADLP) and current Distance Learning practices, with a focus on the Army's training and educational challenges and the benefits of applying Distance Learning techniques...

  20. Conventional versus single-ladder-splitting contributions to double parton scattering production of two quarkonia, two Higgs bosons, and cc xAFcc xAF (United States)

    Gaunt, Jonathan R.; Maciuła, Rafał; Szczurek, Antoni


    The double parton distributions (dPDF), both conventional (i.e. double ladder) and those corresponding to 1→2 ladder splitting, are calculated and compared for different two-parton combinations. The conventional and splitting dPDFs have very similar shape in x1 and x2. We make a first quantitative evaluation of the single-ladder-splitting contribution to double parton scattering (DPS) production of two S- or P-wave quarkonia, two Higgs bosons and cc ¯cc ¯. The ratio of the single-ladder-splitting to conventional (i.e. double ladder against double ladder) contributions is discussed as a function of center-of-mass energy, mass of the produced system and other kinematical variables. Using a simple model for the dependence of the conventional two-parton distribution on transverse parton separation (Gaussian and independent of xi and scales), we find that the single-ladder-splitting (or 2v1) contribution is as big as the conventional (or 2v2) contribution discussed in recent years in the literature. In many experimental studies of DPS, one extracts the quantity 1/σeff=σDPS/(σSPS ,1σSPS,2), with σSPS ,1 and σSPS ,2 being the single scattering cross sections for the two subprocesses in the DPS process. Many past phenomenological studies of DPS have only considered the conventional contribution and have obtained values a factor of ˜2 too small for 1/σeff. Our analysis shows that it is important also to consider the ladder-splitting mechanism, and that this might resolve the discrepancy (this was also pointed out in a recent study by Blok et al.). The differential distributions in rapidity and transverse momenta calculated for conventional and single-ladder-splitting DPS processes are however very similar which causes their experimental separation to be rather difficult, if not impossible. The direct consequence of the existence of the two components (conventional and splitting) is the energy and process dependence of the empirical parameter σeff. This is

  1. DUNDRUM Restriction-Intrusion of Liberty Ladders (DRILL) Audit Toolkit

    LENUS (Irish Health Repository)

    Kennedy, Harry G


    This series of rating \\'ladders\\' is intended to allow a quantitative and qualitative analysis of the use of restrictive and intrusive interventions as part of the therapeutic management of violence and aggression in psychiatric hospital settings. This is an evolving handbook. The ladders are currently organised to facilitate a behavioural analysis. Context, antecedents, behaviour, interventions, consequences are conceptualised as a series of events organised in temporal sequence so that causes, interactions and effects can be considered. The complexity of analysis possible is limited by the statistical power of the numbers of cases and events available. \\r\

  2. Command and Control Career Ladder, AFSC 274X0. (United States)


    I COMMAND AND CONTROL CAREER LADDER AFSC 274X0 AFPT 90-274-774 APRIL 1987 OCCUPATIONAL ANALYSIS PROGRAM USAF OCCUPATIONAL MEASUREMENT CENTER AIR...3 HQ TAC/TTGT 1 1 HQ USAF/XODRF 1 1 HQ USAF/ MPPT 1 1 HQ USAFE/DPAT 3 3 HQ USAFE/TTGT 1 1 HO USMC (CODE TPI) 1 NODAC 1 3300 TCHTW/TTGX (KEESLER AFB MS...Command and Control career ladder (AFSC 274X0). This survey was requested by the Training Development Services Division of the USAF Occupa- tional

  3. Triptycene-based ladder monomers and polymers, methods of making each, and methods of use

    KAUST Repository

    Pinnau, Ingo


    Embodiments of the present disclosure provide for a triptycene-based A-B monomer, a method of making a triptycene-based A-B monomer, a triptycene-based ladder polymer, a method of making a triptycene-based ladder polymers, a method of using triptycene-based ladder polymers, a structure incorporating triptycene-based ladder polymers, a method of gas separation, and the like.

  4. Corrosion Control Specialist Career Ladder AFSC 53530, 53550, 53570, and 53690. Occupational Survey Report. (United States)

    Air Force Occupational Measurement Center, Lackland AFB, TX.

    The report describes the results of a detailed occupational survey of the corrosion control career ladder. Responses to a 457-task, time rating inventory from 1,015 personnel (representing 64 percent of the career field) were analyzed to produce seven specific findings and the career ladder structure. The career ladder includes a variety of jobs…

  5. Cognitive distance (United States)

    Shu, Hong; Edwards, Geoffrey; Qi, Cuihong


    In geographic space, it is well known that spatial behaviors of humans are directly driven by their spatial cognition, rather than by the physical or geometrical reality. The cognitive distance in spatial cognition is fundamental in intelligent pattern recognition. More precisely, the cognitive distance can be used to measure the similarities (or relevance) of cognized geographic objects. In the past work, the physical or Euclidean distances are used very often. In practice, many inconsistencies are found between the cognitive distance and the physical distance. Usually the physical distance is overestimated or underestimated in the process of human spatial behaviors and pattern recognition. These inconsistencies are termed distance distortions. The aim of this paper is to illustrate the conceptions of cognitive distance and distance distortion. And if the cognitive distance is argued to be two-dimensional, it exists in heterogeneous space and the property of quasi-metric is shown. If the cognitive distance is multi-dimensional, it exists in homogeneous space and the property of metric is shown. We argue that distance distortions arise from the transformation of homogeneous to heterogeneous space and from the transformation of the two-dimensional cognitive distance to the multi-dimensional cognitive distance. In some sense, the physical distance is an instance of cognitive distance.

  6. Predictors of Outcomes in a Performance Ladder Program. (United States)

    Dicks, Robert H.; McHenry, James D.


    Investigated variables from initial inmate evaluations at a state penitentiary as predictors of inmate success in behavioral ladder program. Results indicated that academic test variables were best predictors of overall success level, attitudes, and work habits. Personality variables and one interview observation variable were also found to be…

  7. Ladder Ising spin configurations. Pt. 1. Heat capacity

    International Nuclear Information System (INIS)

    Mejdani, R.; Lambros, A.


    We consider a ladder Ising spin model (with two coupled Ising spin chains), characterized by two couplings (interchain and intrachain couplings), to study in detail, in an analytical way, its thermal behaviour and particularly the variation of the specific heat versus temperature, the ratio of interaction constants, and the magnetic field. It is interesting that when the competition between interchain and intrachain interactions is strong the specific heat exhibits a double peak and when the competition is not so strong the specific heat has a single peak. Further, without entering into details, we give, in a numerical way, some similar results for more complicated ladder configurations (with more than two linear Ising chains). The spin-1/2 ladders or systems of spin chains may be realized in nature by vanadyl pyrophosphate ((VO) 2 P 2 O 7 ) or similar materials. All these intermediate systems are today important to gain further insight into the physics of one-dimensional spin chains and two-dimensional high-T c spin systems, both of which have shown interesting and unusual magnetic and superconducting properties. It is plausible that experimental and theoretical studies of ladders may lead to other interesting physical phenomena. (orig.)

  8. A robustification of the chain-ladder method

    NARCIS (Netherlands)

    Verdonck, T.; van Wouwe, M.; Dhaene, J.


    In a non-life insurance business an insurer often needs to build up a reserve to able to meet his or her future obligations arising from incurred but not reported completely claims. To forecast these claims reserves, a simple but generally accepted algorithm is the classical chain-ladder method.

  9. Workload of window cleaners using ladders differing in rung separation

    NARCIS (Netherlands)

    Hoozemans, M.J.M.; Looze, M.P. de; Kingma, I.; Reijneveld, K.C.N.; Korte, E.M. de; Grinten, M.P. van der; Dieën, J.H. van


    The objective of the present study was to compare energetic workload, perceived exertion, perceived discomfort, safety, and mechanical load at lower limb joints among window cleaners during usage of extension ladders with 30 and 35 cm rung separation. Eleven healthy male professional window cleaners

  10. Dynamic parameterization and ladder operators for the Kratzer molecular potential

    International Nuclear Information System (INIS)

    Devi, O Babynanda; Singh, C Amuba


    Introducing independent parameters k and δ to represent the strength of the attractive and repulsive components, respectively, we write the Kratzer molecular potential as V(k,δ)=(ℏ 2 /2 m)(−k/r+δ(δ−1)/r 2 ). This parameterisation is not only natural, but also convenient for the construction of ladder operators for the system. Adopting the straightforward method of deriving recurrence relations among confluent hypergeometric functions, we construct seven pairs of ladder operators for the Kratzer potential system. Detailed analysis of the laddering actions of these operators is given to show that they connect eigenstates of equal energy but belong to a hierarchy of Kratzer potential systems corresponding to different values of the parameters k and δ. Significantly, it is pointed out that it may not be possible to construct, in the position representation, a ladder operator which would connect different eigenstates belonging to the same potential V(k,δ). Transition to the hydrogen atom case is discussed. A number (14 altogether) of functional relations among the confluent hypergeometric functions have been derived and reported separately in an appendix. (paper)

  11. Towards flavored bound states beyond rainbows and ladders

    International Nuclear Information System (INIS)

    El-Bennich, B.; Rojas, E.; Melo, J. P. B. C. de; Paracha, M. A.


    We give a snapshot of recent progress in solving the Dyson-Schwinger equation with a beyond rainbow-ladder ansatz for the dressed quark-gluon vertex which includes ghost contributions. We discuss the motivations for this approach with regard to heavy-flavored bound states and form factors and briefly describe future steps to be taken

  12. Education for Sustainability: A Snakes and Ladders Game?

    Directory of Open Access Journals (Sweden)

    Daniella Tilbury


    Full Text Available How to reference this articleTilbury, D. (2015. Education for Sustainability: A Snakes and Ladders Game?. Foro de Educación, 13(19, 7-10. doi:

  13. The C-terminus of Wheat streak mosaic virus coat protein is involved in differential infection of wheat and maize through host-specific long-distance transport. (United States)

    Tatineni, Satyanarayana; French, Roy


    Viral determinants and mechanisms involved in extension of host range of monocot-infecting viruses are poorly understood. Viral coat proteins (CP) serve many functions in almost every aspect of the virus life cycle. The role of the C-terminal region of Wheat streak mosaic virus (WSMV) CP in virus biology was examined by mutating six negatively charged aspartic acid residues at positions 216, 289, 290, 326, 333, and 334. All of these amino acid residues are dispensable for virion assembly, and aspartic acid residues at positions 216, 333, and 334 are expendable for normal infection of wheat and maize. However, mutants D289N, D289A, D290A, DD289/290NA, and D326A exhibited slow cell-to-cell movement in wheat, which resulted in delayed onset of systemic infection, followed by a rapid recovery of genomic RNA accumulation and symptom development. Mutants D289N, D289A, and D326A inefficiently infected maize, eliciting milder symptoms, while D290A and DD289/290NA failed to infect systemically, suggesting that the C-terminus of CP is involved in differential infection of wheat and maize. Mutation of aspartic acid residues at amino acid positions 289, 290, and 326 severely debilitated virus ingress into the vascular system of maize but not wheat, suggesting that these amino acids facilitate expansion of WSMV host range through host-specific long-distance transport.

  14. Falls from ladders: age matters more than height. (United States)

    Con, Jorge; Friese, Randall S; Long, Dustin M; Zangbar, Bardiya; O'Keeffe, Terence; Joseph, Bellal; Rhee, Peter; Tang, Andrew L


    Falls from ladders account for a significant number of hospital visits. However, the epidemiology, injury pattern, and how age affects such falls are poorly described in the literature. Patients ≥18 y who suffered falls from ladders over a 5½-y period were identified in our trauma registry. Dividing patients into three age groups (18-45, 46-65, and >66 y), we compared demographic characteristics, clinical data, and outcomes including injury pattern and mortality. The odds ratios (ORs) were calculated with the group 18-45 y as reference; group means were compared with one-way analysis of variance. Of 27,155 trauma patients, 340 (1.3%) had suffered falls from ladders. The average age was 55 y, with a male predominance of 89.3%. Average fall height was 9.8 ft, and mean Injury Severity Score was 10.6. Increasing age was associated with a decrease in the mean fall height (P 66 y: OR, 5.3; confidence interval [CI], 2.5-11.5). In univariate analysis, patients in the >66-y age group were more likely to sustain traumatic brain injuries (OR, 3.4; CI, 1.5-7.8) and truncal injuries (OR, 3.6; CI, 1.9-7.0) and less likely to sustain hand and/or forearm fractures (OR, 0.3; CI, 0.1-0.9). Older people are particularly vulnerable after falling from ladders. Although they fell from lower heights, the elderly sustained different and more severe injury patterns. Ladder safety education should be particularly tailored at the elderly. Copyright © 2014 Elsevier Inc. All rights reserved.

  15. Phase diagram of a bosonic ladder with two coupled chains

    International Nuclear Information System (INIS)

    Luthra, Meetu Sethi; Mishra, Tapan; Pai, Ramesh V.; Das, B. P.


    We study a bosonic ladder with two coupled chains using the finite-size density-matrix renormalization group method. We show that in a commensurate bosonic ladder the critical on-site interaction (U C ) for the superfluid to Mott insulator transition gets larger as the interchain hopping (t perpendicular ) increases. We analyze this quantum phase transition and obtain the phase diagram in the t perpendicular -U plane. We also consider the asymmetric case where the on-site interactions are different in the two chains and have shown that the system as a whole will not be in the Mott insulator phase unless both the chains have on-site interactions greater than the critical value

  16. Tests of prototype ITS-SSD Ladder and Fixators

    CERN Document Server

    Van den Brink, D J; CERN. Geneva; Nooren, G J L; Feofilov, G A; Igolkin, S N; Daudo, F; Giraudo, G; van den Broek, D J


    Abstract A prototype carbon fibre SSD ladder, produced in St.Petersburg, was equipped in Utrecht with mounting blocks, designed in Torino, for the fixation on the ITS cone. Instead of the cone, a specially designed jig was used. The mechanical properties were measured in order to find out whether the design and the production method are compliant with the requirements given in the TDR.

  17. Medical humanities in Nepal--snakes and ladders. (United States)

    Shankar, P Ravi; Piryani, R M; Morgan, Huw; Thapa, T P


    In the last decade there has been a quantitative growth in medical schools in Nepal, a developing country in South Asia. Medical Humanities (MH) uses disciplines traditionally termed as the humanities in the pursuit of medical educational goals. The subject is slowly developing in Nepal. Sessions have been conducted at Manipal College of Medical Sciences, Pokhara and KIST Medical College, Lalitpur. In this article the authors examine inhibitory factors (snakes) and facilitating factors (ladders) for the development of the subject in Nepal.

  18. The search for competing charge orders in frustrated ladder systems

    International Nuclear Information System (INIS)

    Lal, Siddhartha; Laad, Mukul S.


    A recent study revealed the dynamics of the charge sector of a one-dimensional quarter- filled electronic system with extended Hubbard interactions to be that of an effective pseudospin transverse-field Ising model (TFIM) in the strong coupling limit. With the twin motivations of studying the co-existing charge and spin order found in strongly correlated chain systems and the effects of inter-chain couplings, we investigate the phase diagram of coupled effective (TFIM) systems. A bosonisation and RG analysis for a two-leg TFIM ladder yields a rich phase diagram showing Wigner/Peierls charge order and Neel/dimer spin order. In a broad parameter regime, the orbital antiferromagnetic phase is found to be stable. An intermediate gapless phase of finite width is found to lie in between two charge-ordered gapped phases. Kosterlitz-Thouless transitions are found to lead from the gapless phase to either of the charge-ordered phases. Low energy effective Hamiltonian analyses of a strongly coupled 2-chain ladder system confirm a phase diagram with in-chain CO, rung-dimer, and orbital antiferromagnetic ordered phases with varying interchain couplings as well as superconductivity upon hole-doping. Our work is potentially relevant for a unified description of a class of strongly correlated, quarter-filled chain and ladder systems. (autor)

  19. Strength Analysis on Ship Ladder Using Finite Element Method (United States)

    Budianto; Wahyudi, M. T.; Dinata, U.; Ruddianto; Eko P., M. M.


    In designing the ship’s structure, it should refer to the rules in accordance with applicable classification standards. In this case, designing Ladder (Staircase) on a Ferry Ship which is set up, it must be reviewed based on the loads during ship operations, either during sailing or at port operations. The classification rules in ship design refer to the calculation of the structure components described in Classification calculation method and can be analysed using the Finite Element Method. Classification Regulations used in the design of Ferry Ships used BKI (Bureau of Classification Indonesia). So the rules for the provision of material composition in the mechanical properties of the material should refer to the classification of the used vessel. The analysis in this structure used program structure packages based on Finite Element Method. By using structural analysis on Ladder (Ladder), it obtained strength and simulation structure that can withstand load 140 kg both in static condition, dynamic, and impact. Therefore, the result of the analysis included values of safety factors in the ship is to keep the structure safe but the strength of the structure is not excessive.

  20. Development of ultra-light pixelated ladders for an ILC vertex detector

    CERN Document Server

    Chon-Sen, N.; Claus, G.; De Masi, R.; Deveaux, M.; Dulinski, W.; Goffe, M.; Goldstein, J.; Gregor, I.-M.; Hu-Guo, Ch.; Imhoff, M.; Muntz, C.; Nomerotski, A.; Santos, C.; Schrader, C.; Specht, M.; Stroth, J.; Winter, M.


    The development of ultra-light pixelated ladders is motivated by the requirements of the ILD vertex detector at ILC. This paper summarizes three projects related to system integration. The PLUME project tackles the issue of assembling double-sided ladders. The SERWIETE project deals with a more innovative concept and consists in making single-sided unsupported ladders embedded in an extra thin plastic enveloppe. AIDA, the last project, aims at building a framework reproducing the experimental running conditions where sets of ladders could be tested.

  1. Multi-material size optimization of a ladder frame chassis (United States)

    Baker, Michael

    The Corporate Average Fuel Economy (CAFE) is an American fuel standard that sets regulations on fuel economy in vehicles. This law ultimately shapes the development and design research for automakers. Reducing the weight of conventional cars offers a way to improve fuel efficiency. This research investigated the optimality of an automobile's ladder frame chassis (LFC) by conducting multi-objective optimization on the LFC in order to reduce the weight of the chassis. The focus of the design and optimization was a ladder frame chassis commonly used for mass production light motor vehicles with an open-top rear cargo area. This thesis is comprised of two major sections. The first looked to perform thickness optimization in the outer walls of the ladder frame. In the second section, many multi-material distributions, including steel and aluminium varieties, were investigated. A simplified model was used to do an initial hand calculation analysis of the problem. This was used to create a baseline validation to compare the theory with the modeling. A CAD model of the LFC was designed. From the CAD model, a finite element model was extracted and joined using weld and bolt connectors. Following this, a linear static analysis was performed to look at displacement and stresses when subjected to loading conditions that simulate harsh driving conditions. The analysis showed significant values of stress and displacement on the ends of the rails, suggesting improvements could be made elsewhere. An optimization scheme was used to find the values of an all steel frame an optimal thickness distribution was found. This provided a 13% weight reduction over the initial model. To advance the analysis a multi-material approach was used to push the weight savings even further. Several material distributions were analyzed and the lightest utilized aluminium in all but the most strenuous subjected components. This enabled a reduction in weight of 15% over the initial model, equivalent to

  2. Ising versus S U (2) 2 string-net ladder (United States)

    Vidal, Julien


    We consider the string-net model obtained from S U (2) 2 fusion rules. These fusion rules are shared by two different sets of anyon theories. In this paper, we study the competition between the two corresponding non-Abelian quantum phases in the ladder geometry. A detailed symmetry analysis shows that the nontrivial low-energy sector corresponds to the transverse-field cluster model that displays a critical point described by the s o (2) 1 conformal field theory. Other sectors are obtained by freezing spins in this model.

  3. Breathers in Josephson junction ladders: Resonances and electromagnetic wave spectroscopy

    DEFF Research Database (Denmark)

    Miroshnichenko, A. E.; Flach, S.; Fistul, M.


    We present a theoretical study of the resonant interaction between dynamical localized states (discrete breathers) and linear electromagnetic excitations (EE's) in Josephson junction ladders. By making use of direct numerical simulations we find that such an interaction manifests itself by resonant...... steps and various sharp switchings (voltage jumps) in the current-voltage characteristics. Moreover, the power of ac oscillations away from the breather center (the breather tail) displays singularities as the externally applied dc bias decreases. All these features may be mapped to the spectrum of EE...

  4. Education Career Ladder, AFSC 751X0. Volume II. (United States)


    I AD-A099 152 AIR FORCE OCCUPATIONAL MEASUREMENT CENTER RANDOLPH AFO TX F/S 5/9 I EDUCATION CAREER LADDER, AFSC 7151X0. VOLUME II.(U) I UNCLASSIFIED...percentages of incumbents, such as: service operated schools, education surveys, and support for dependent children . In terms of the main aspect of...DETERMINE BASE REQUIREMENTS FOR EDUCATIONAL SERVICE PROGRAMS 6.45 24 F183 SCHEDULE SCHOOL TRANSPORTATION OF DEPENDENT CHILDREN 6.44 15 E166 REVIEW

  5. Estimating ladder fuels: a new approach combining field photography with LiDAR (United States)

    Heather Kramer; Brandon Collins; Frank Lake; Marek Jakubowski; Scott Stephens; Maggi Kelly


    Forests historically associated with frequent fire have changed dramatically due to fire suppression and past harvesting over the last century. The buildup of ladder fuels, which carry fire from the surface of the forest floor to tree crowns, is one of the critical changes, and it has contributed to uncharacteristically large and severe fires. The abundance of ladder...

  6. 29 CFR 1910.29 - Manually propelled mobile ladder stands and scaffolds (towers). (United States)


    .... (stress grade) construction grade lumber or equivalent. (vi) All scaffold work levels 10 feet or higher..., construction, and use of mobile work platforms (including ladder stands but not including aerial ladders) and... the use of mobile work platforms and towers. (2) Working loads. (i) Work platforms and scaffolds shall...

  7. Dissipation, Voltage Profile and Levy Dragon in a Special Ladder Network (United States)

    Ucak, C.


    A ladder network constructed by an elementary two-terminal network consisting of a parallel resistor-inductor block in series with a parallel resistor-capacitor block sometimes is said to have a non-dispersive dissipative response. This special ladder network is created iteratively by replacing the elementary two-terminal network in place of the…

  8. Measuring subjective meaning structures by the laddering method: Theoretical considerations and methodological problems

    DEFF Research Database (Denmark)

    Grunert, Klaus G.; Grunert, Suzanne C.


    and applied, which refer to data collection, coding, and analysis. These criteria are evaluated using examples from a laddering study where additional data was collected to shed light on respondents' subj interpretation of the laddering task as well as interviewers' experiences with it. Several possible...

  9. The Structure of Opportunity: How Promotion Ladders Vary within and among Organizations. (United States)

    Baron, James N.; And Others


    Data describing jobs in 100 establishments are analyzed to test hypotheses about the characteristics of jobs and organizations associated with the structure of internal promotion ladders. Hypotheses are supported that link job ladders to, for example, organizational structure, gender distinctions, and technology. The formation of promotion ladders…

  10. Passage and behaviour of cultured Lake Sturgeon in a prototype side-baffle fish ladder: I. Ladder hydraulics and fish ascent (United States)

    Kynard, B.; Pugh, D.; Parker, T.


    Research and development of a fish ladder for sturgeons requires understanding ladder hydraulics and sturgeon behaviour in the ladder to insure the ladder is safe and provides effective passage. After years of research and development, we designed and constructed a full-scale prototype side-baffle ladder inside a spiral flume (38.3m long??1m wide??1m high) on a 6% (1:16.5) slope with a 1.92-m rise in elevation (bottom to top) to test use by sturgeons. Twenty-eight triangular side baffles, each extending part way across the flume, alternated from inside wall to outside wall down the ladder creating two major flow habitats: a continuous, sinusoidal flow down the ladder through the vertical openings of side-baffles and an eddy below each side baffle. Ascent and behaviour was observed on 22 cultured Lake Sturgeon=LS (Acipenser fulvescens) repeatedly tested in groups as juveniles (as small as 105.1cm TL, mean) or as adults (mean TL, 118cm) during four periods (fall 2002 and 2003; spring 2003 and 2007). Percent of juveniles entering the ladder that ascended to the top was greater in spring (72.7%) than in fall (40.9-45.5%) and 90.9% of 11 adults, which ascended as juveniles, ascended to the top. Six LS (27.3%) never swam to the top and seven (31.8%) swam to the top in all tests, indicating great variability among individuals for ascent drive. Some LS swam directly to the top in <1min, but most rested in an eddy during ascent. Juveniles swimming through outside wall baffle slots (mean velocity, 1.2ms-1) swam at 1.8-2.2body lengthss-1 and 3.2-3.3tail beatss-1, either at or approaching prolonged swimming speed. The side-baffle ladder was stream-like and provided key factors for a sturgeon ladder: a continuous flow and no full cross-channel walls, abundant eddies for resting, an acceptable water depth, and a water velocity fish could ascend swimming 2bls-1. A side-baffle ladder passes LS and other moderate-swimming fishes. ?? 2011 Blackwell Verlag, Berlin.

  11. Impact of inter-ladder coupling in a coupled spin-1/2 two-leg ladder (United States)

    Hong, Tao; Schmidt, K. P.; Coester, K.; Awwadi, F. F.; Turnbull, M. M.; Qiu, Y.; Rodriguez, J. A.; Ke, X.; Aoyama, C.; Takano, Y.; Cao, H.; Tian, W.; Ma, J.; Custelcean, R.; Zhou, H. D.; Matsuda, M.


    We present the zero-field specific heat and neutron scattering studies on an S = 1/2 Heisenberg antiferromagnet to understand the nature of its spin Hamiltonian. The system is magnetically ordered below TN = 2.0(1) K. The conclusion that the system is best described as coupled two-leg spin-1/2 ladders is supported by the material structure, neutron scattering measurements, and theoretical calculation. The work at the HFIR, ORNL was sponsored by the Division of Scientific User Facilities, Office of Basic Energy Science, US Department of Energy.

  12. Action–angle variables, ladder operators and coherent states

    International Nuclear Information System (INIS)

    Campoamor-Stursberg, R.; Gadella, M.; Kuru, Ş.; Negro, J.


    This Letter is devoted to the building of coherent states from arguments based on classical action–angle variables. First, we show how these classical variables are associated to an algebraic structure in terms of Poisson brackets. In the quantum context these considerations are implemented by ladder type operators and a structure known as spectrum generating algebra. All this allows to generate coherent states and thereby the correspondence of classical–quantum properties by means of the aforementioned underlying structure. This approach is illustrated with the example of the one-dimensional Pöschl–Teller potential system. -- Highlights: ► We study the building of coherent states from classical action–angle variables arguments. ► The classical variables are associated to an algebraic structure in terms of Poisson brackets. ► In the quantum context these considerations are implemented by ladder type operators. ► All this allows to formulate coherent states and the correspondence of classical–quantum properties.

  13. SUSY’s Ladder: reframing sequestering at Large Volume

    Energy Technology Data Exchange (ETDEWEB)

    Reece, Matthew [Department of Physics, Harvard University,Cambridge, MA 02138 (United States); Xue, Wei [Center for Theoretical Physics, Massachusetts Institute of Technology,Cambridge, MA 02139 (United States)


    Theories with approximate no-scale structure, such as the Large Volume Scenario, have a distinctive hierarchy of multiple mass scales in between TeV gaugino masses and the Planck scale, which we call SUSY’s Ladder. This is a particular realization of Split Supersymmetry in which the same small parameter suppresses gaugino masses relative to scalar soft masses, scalar soft masses relative to the gravitino mass, and the UV cutoff or string scale relative to the Planck scale. This scenario has many phenomenologically interesting properties, and can avoid dangers including the gravitino problem, flavor problems, and the moduli-induced LSP problem that plague other supersymmetric theories. We study SUSY’s Ladder using a superspace formalism that makes the mysterious cancelations in previous computations manifest. This opens the possibility of a consistent effective field theory understanding of the phenomenology of these scenarios, based on power-counting in the small ratio of string to Planck scales. We also show that four-dimensional theories with approximate no-scale structure enforced by a single volume modulus arise only from two special higher-dimensional theories: five-dimensional supergravity and ten-dimensional type IIB supergravity. This gives a phenomenological argument in favor of ten dimensional ultraviolet physics which is different from standard arguments based on the consistency of superstring theory.

  14. Frustrated spin-1/2 ladder with ferro- and antiferromagnetic legs (United States)

    Maiti, Debasmita; Dey, Dayasindhu; Kumar, Manoranjan


    Two-leg spin-1/2 ladder systems consisting of a ferromagnetic leg and an antiferromagnetic leg are considered where the spins on the legs interact through antiferromagnetic rung couplings J1 . These ladders can have two geometrical arrangements either zigzag or normal ladder and these systems are frustrated irrespective of their geometry. This frustration gives rise to incommensurate spin density wave, dimer and spin fluid phases in the ground state. The magnetization in the systems decreases linearly with J12, and the systems show an incommensurate phase for 0.0 ladder behaves like a collection of singlet dimers, whereas the zigzag ladder behaves as a one dimensional spin-1/2 antiferromagnetic chain.

  15. Topological phases in frustrated synthetic ladders with an odd number of legs (United States)

    Barbarino, Simone; Dalmonte, Marcello; Fazio, Rosario; Santoro, Giuseppe E.


    The realization of the Hofstadter model in a strongly anisotropic ladder geometry has now become possible in one-dimensional optical lattices with a synthetic dimension. In this work, we show how the Hofstadter Hamiltonian in such ladder configurations hosts a topological phase of matter which is radically different from its two-dimensional counterpart. This topological phase stems directly from the hybrid nature of the ladder geometry and is protected by a properly defined inversion symmetry. We start our analysis by considering the paradigmatic case of a three-leg ladder which supports a topological phase exhibiting the typical features of topological states in one dimension: robust fermionic edge modes, a degenerate entanglement spectrum, and a nonzero Zak phase; then, we generalize our findings—addressable in the state-of-the-art cold-atom experiments—to ladders with a higher number of legs.

  16. Assembly procedure for the silicon pixel ladder for PHENIX silicon vertex tracker

    International Nuclear Information System (INIS)

    Onuki, Y.; Akiba, Y.; En'yo, H.; Fujiwara, K.; Haki, Y.; Hashimoto, K.; Ichimiya, R.; Kasai, M.; Kawashima, M.; Kurita, K.; Kurosawa, M.; Mannel, E.J.; Nakano, K.; Pak, R.; Sekimoto, M.; Sondheim, W.E.; Taketani, A.; Togawa, M.; Yamamoto, Y.


    The silicon vertex tracker (VTX) will be installed in the summer of 2010 to enhance the physics capabilities of the Pioneering High Energy Nuclear Interaction eXperiment (PHENIX) experiment at Brookhaven National Laboratory. The VTX consists of two types of silicon detectors: a pixel detector and a strip detector. The pixel detector consists of 30 pixel ladders placed on the two inner cylindrical layers of the VTX. The ladders are required to be assembled with high precision, however, they should be assembled in both cost and time efficient manner. We have developed an assembly bench for the ladder with several assembly fixtures and a quality assurance (Q/A) system using a 3D measurement machine. We have also developed an assembly procedure for the ladder, including a method for dispensing adhesive uniformly and encapsulation of bonding wires. The developed procedures were adopted in the assembly of the first pixel ladder and satisfy the requirements.

  17. Movements of adult Atlantic salmon in relation to a hydroelectric dam and fish ladder

    International Nuclear Information System (INIS)

    Gowans, A.R.D.; Priede, I.G.


    The movements of adult Atlantic salmon were recorded as they approached, entered and ascended the pool-and-orifice fish ladder at Pitlochry Dam, Scotland. Thirty-nine returning salmon were captured in the River Tummel by rod-and-line angling, radio-tagged and released near where they were caught. The subsequent movements of each fish were then monitored. An electronic fish counter collected additional data on movements of untagged fish past a fixed point in the ladder. Of the 39 fish that were radio-tagged, 29 individuals were recorded approaching and ascending the ladder. The remaining fish either did not approach the dam (three fish), approached the dam after detailed tracking had ended (two fish), were recaptured by anglers (three fish), or the radio tags failed (two fish). Salmon released earlier in the year delayed longer before first approaching the dam. Delays between first approaching the dam and ascent of the ladder were greater for fish that approached the dam earlier. The majority of salmon visited the ladder entrance more than once (maximum 10 visits) before ascending. Having entered, all but four salmon ascended the fish ladder successfully on their first attempt. The four individuals that failed to do so succeeded on their second attempt. The rate at which salmon ascended the ladder was related directly to temperature. The shortest ascent time of a radio-tagged salmon was 5.25 h. Movements of eight of 11 tagged fish through the ladder ceased with the onset of darkness but continued on the following morning. No radio-tagged fish entered the ladder at temperatures below 9 o C. Similarly, few untagged fish were recorded ascending the ladder by the electronic fish counter at water temperatures below 8.5 o C. Records from the fish counter indicated that 92% of upstream movements were made during daylight. (author)

  18. Mahalanobis Distance

    Indian Academy of Sciences (India)

    Further Suggested Reading. [1] PC Mahalanobis, A statistical study oftbe Chinese hud, Man in India,. 8, 107-122, 1928. [2] PC Mahalanobis, On the generalised distance in statistics, Proceedings of the National Institute of Sciences of India, 2, 49-55, 1936. [3] P C Mahalanobis, Normalisation of statistical variates and the use ...

  19. Quantum phase transitions in effective spin-ladder models for graphene zigzag nanoribbons (United States)

    Koop, Cornelie; Wessel, Stefan


    We examine the magnetic correlations in quantum spin models that were derived recently as effective low-energy theories for electronic correlation effects on the edge states of graphene nanoribbons. For this purpose, we employ quantum Monte Carlo simulations to access the large-distance properties, accounting for quantum fluctuations beyond mean-field-theory approaches to edge magnetism. For certain chiral nanoribbons, antiferromagnetic interedge couplings were previously found to induce a gapped quantum disordered ground state of the effective spin model. We find that the extended nature of the intraedge couplings in the effective spin model for zigzag nanoribbons leads to a quantum phase transition at a large, finite value of the interedge coupling. This quantum critical point separates the quantum disordered region from a gapless phase of stable edge magnetism at weak intraedge coupling, which includes the ground states of spin-ladder models for wide zigzag nanoribbons. To study the quantum critical behavior, the effective spin model can be related to a model of two antiferromagnetically coupled Haldane-Shastry spin-half chains with long-ranged ferromagnetic intrachain couplings. The results for the critical exponents are compared also to several recent renormalization-group calculations for related long-ranged interacting quantum systems.

  20. Design of Dual Bandpass and Bandreject LC Ladder Filters

    Directory of Open Access Journals (Sweden)

    J. Hospodka


    Full Text Available This paper deals with the design of two-passband bandpass and two-stopband bandreject LC ladder filters. The design method is based on the special dual frequency transformation that transforms normalized lowpass to either bandpass with two passbands or to bandreject with two stopbands that are specified by four cutoff frequencies. The paper shows analytical solution relating these four cutoff frequencies to parameters of dual frequency transformation. It enables a direct computation of dual band LC filter elements from a normalized lowpass filter by means of simple relations. These relations have been implemented in the mathematical program Maple (TM as new user functions. They are supposed to be used as an enhancement of Syntfil package which is intended for analog filter design in program Maple. Specific application is shown on an example of the two-passband bandpass LC filter design.

  1. Nested Bethe Ansatz for Spin Ladder Model with Open Boundary Conditions

    International Nuclear Information System (INIS)

    Wu Junfang; Zhang Chunmin; Yue Ruihong; Li Runling


    The nested Bethe ansatz (BA) method is applied to find the eigenvalues and the eigenvectors of the transfer matrix for spin-ladder model with open boundary conditions. Based on the reflection equation, we find the general diagonal solution, which determines the general boundary interaction in the Hamiltonian. We introduce the spin-ladder model with open boundary conditions. By finding the solution K ± of the reflection equation which determines the nontrivial boundary terms in the Hamiltonian, we diagonalize the transfer matrix of the spin-ladder model with open boundary conditions in the framework of nested BA.

  2. Conventional versus single-ladder-splitting contributions to double parton scattering production of two quarkonia, two Higgs bosons and c anti cc anti c

    Energy Technology Data Exchange (ETDEWEB)

    Gaunt, Jonathan R. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany). Theory Group; Maciula, Rafal [Polish Academy of Sciences, Cracow (Poland). Inst. of Nuclear Physics; Szczurek, Antoni [Polish Academy of Sciences, Cracow (Poland). Inst. of Nuclear Physics; Rzeszow Univ. (Poland)


    The double parton distributions (dPDF), both conventional and those corresponding to parton splitting, are calculated and compared for different two-parton combinations. The conventional and splitting dPDFs have very similar shape in x{sub 1} and x{sub 2}. We make a first quantitative evaluation of the single-ladder-splitting contribution to double parton scattering (DPS) production of two S- or P-wave quarkonia, two Higgs bosons and c anti cc anti c. The ratio of the single-ladder-splitting to conventional contributions is discussed as a function of centre-of-mass energy, mass of the produced system and other kinematical variables. Using a simple model for the dependence of the conventional two-parton distribution on transverse parton separation (Gaussian and independent of x{sub i} and scales), we find that the 2v1 contribution is as big as the 2v2 contribution discussed in recent years in the literature. This means that the phenomenological analyses of σ{sub eff} including only the conventional DPS mechanism have to be revised including explicitly the single-ladder-splitting contributions discussed here. The differential distributions in rapidity and transverse momenta calculated for conventional and single-ladder-splitting DPS processes are however very similar which causes their experimental separation to be rather difficult, if not impossible. The direct consequence of the existence of the two components (conventional and splitting) is the energy and process dependence of the empirical parameter σ{sub eff}. This is illustrated in our paper for the considered processes.

  3. Isolation by distance and isolation by environment contribute to population differentiation in Protea repens (Proteaceae L.), a widespread South African species. (United States)

    Prunier, Rachel; Akman, Melis; Kremer, Colin T; Aitken, Nicola; Chuah, Aaron; Borevitz, Justin; Holsinger, Kent E


    The Cape Floristic Region (CFR) of South Africa is renowned for its botanical diversity, but the evolutionary origins of this diversity remain controversial. Both neutral and adaptive processes have been implicated in driving diversification, but population-level studies of plants in the CFR are rare. Here, we investigate the limits to gene flow and potential environmental drivers of selection in Protea repens L. (Proteaceae L.), a widespread CFR species. We sampled 19 populations across the range of P. repens and used genotyping by sequencing to identify 2066 polymorphic loci in 663 individuals. We used a Bayesian F ST outlier analysis to identify single-nucleotide polymorphisms (SNPs) marking genomic regions that may be under selection; we used those SNPs to identify potential drivers of selection and excluded them from analyses of gene flow and genetic structure. A pattern of isolation by distance suggested limited gene flow between nearby populations. The populations of P. repens fell naturally into two or three groupings, which corresponded to an east-west split. Differences in rainfall seasonality contributed to diversification in highly divergent loci, as do barriers to gene flow that have been identified in other species. The strong pattern of isolation by distance is in contrast to the findings in the only other widespread species in the CFR that has been similarly studied, while the effects of rainfall seasonality are consistent with well-known patterns. Assessing the generality of these results will require investigations of other CFR species. © 2017 Prunier et al. Published by the Botanical Society of America. This work is licensed under a Creative Commons Attribution License (CC-BY-NC).

  4. Calculating three loop ladder and V-topologies for massive operator matrix elements by computer algebra

    International Nuclear Information System (INIS)

    Ablinger, J.; Schneider, C.; Manteuffel, A. von


    Three loop ladder and V-topology diagrams contributing to the massive operator matrix element A Qg are calculated. The corresponding objects can all be expressed in terms of nested sums and recurrences depending on the Mellin variable N and the dimensional parameter ε. Given these representations, the desired Laurent series expansions in ε can be obtained with the help of our computer algebra toolbox. Here we rely on generalized hypergeometric functions and Mellin-Barnes representations, on difference ring algorithms for symbolic summation, on an optimized version of the multivariate Almkvist-Zeilberger algorithm for symbolic integration, and on new methods to calculate Laurent series solutions of coupled systems of differential equations. The solutions can be computed for general coefficient matrices directly for any basis also performing the expansion in the dimensional parameter in case it is expressible in terms of indefinite nested product-sum expressions. This structural result is based on new results of our difference ring theory. In the cases discussed we deal with iterative sum- and integral-solutions over general alphabets. The final results are expressed in terms of special sums, forming quasi-shuffle algebras, such as nested harmonic sums, generalized harmonic sums, and nested binomially weighted (cyclotomic) sums. Analytic continuations to complex values of N are possible through the recursion relations obeyed by these quantities and their analytic asymptotic expansions. The latter lead to a host of new constants beyond the multiple zeta values, the infinite generalized harmonic and cyclotomic sums in the case of V-topologies.

  5. Surface Acoustic Analog of Bloch Oscillations, Wannier-Stark Ladders and Landau-Zener Tunneling (United States)

    de Lima, M. M.; Kosevich, Yu. A.; Santos, P. V.; Cantarero, A.


    In this contribution, we discuss the recent experimental demonstration of Wannier-Stark ladders, Bloch Oscillations and Landau Zener tunneling in a solid by means of surface acoustic waves propagating through perturbed grating structures.

  6. Generalized ladder operators for the Dirac-Coulomb problem via SUSY QM

    International Nuclear Information System (INIS)

    Rodrigues, R. de Lima; Universidade Federal de Campina Grande, PB


    The supersymmetry in quantum mechanics and shape invariance condition are applied as an algebraic method to solving the Dirac-Coulomb problem. The ground state and the excited states are investigated via new generalized ladder operators. (author)

  7. Cutting and dismantling of the South West ladder of the Atucha I nuclear power plant

    International Nuclear Information System (INIS)

    Anasco, Roberto


    The metallic ladder built in stainless steel was used originally to check the welding of the reactor pressure vessel. It was located between the thermal insulation and reactor pressure vessel. Because of a failure in the mechanism, which let the ladder runs around the vessel, it had to be removed. A special tool remotely operated was designed to make different cuts in the bottom of the structure in a very high radioactive location [es

  8. Differential identification of atypical pneumonia pathogens in aorta and internal mammary artery related to ankle brachial index and walking distance. (United States)

    Iriz, Erkan; Cirak, Meltem Yalinay; Zor, Mustafa Hakan; Engin, Doruk; Oktar, Levent; Unal, Yusuf


    We studied the existence of agents in aorta biopsies, such as Chlamydia pneumoniae, cytomegalovirus, and Mycoplasma pneumoniae, that are thought to have a role in atherosclerosis etiopathogenesis role, and their association with peripheral artery disease. We examined aorta wall and internal mammarian artery (IMA) biopsies taken from two different places in 63 patients in whom coronary artery bypass was performed. In these biopsies, we evaluated the deoxyribonuclease (DNA) of these microorganisms using polymerase chain reaction. From the same patients, we recorded the ankle brachial index, road walking distance information, lipid profile, C-reactive proteins, blood parameters such as fibrinogen, and the patient's operation data. In the nine aorta biopsies taken from 63 patients, we isolated C pneumoniae DNA. In IMA biopsies taken from the same patients, we detected no microorganism DNA (P artery disease. In the development of atherosclerosis with C pneumoniae, there may be a determinant pathogen in both the aorta and the peripheral arteries. The nonexistence of C pneumoniae DNA in the IMA biopsies may indicate infectious agents because of the predominant endothelial functions in this artery, and thus its resistance to atherosclerosis. Copyright © 2013 Elsevier Inc. All rights reserved.

  9. Differential catabolism of muscle protein in garden warblers (Sylvia borin): flight and leg muscle act as a protein source during long-distance migration. (United States)

    Bauchinger, U; Biebach, H


    Samples of flight and leg muscle tissue were taken from migratory garden warblers at three different stages of migration: (1) pre-flight: when birds face an extended flight phase within the next few days, (2) post-flight: when they have just completed an extended flight phase, and (3) recovery: when they are at the end of a stop-over period following an extended flight phase. The changes in body mass are closely related to the changes in flight (Pflight. From pre- to post-flight, the flight and the leg muscle masses decrease by about 22%, but are restored to about 12% above the pre-flight masses during the recovery period. Biochemical analyses show that following flight a selective reduction occurred in the myofibrillar (contractile) component of the flight muscle (Pflight and leg muscle act as a protein source during long-distance migration. As a loss of leg muscle mass is additionally observed besides the loss in flight muscle mass, mass change seems not to be strictly associated with the mechanical power output requirements during flight. Whereas the specific content of sarcoplasmic proteins in the flight muscle is nearly twice as high as that in the leg muscle (Pflight muscle is one of the highest observed in muscles of a vertebrate.

  10. Shoulder muscle loading and task performance for overhead work on ladders versus Mobile Elevated Work Platforms. (United States)

    Phelan, Denis; O'Sullivan, Leonard


    A high incidence of Musculoskeletal Disorders (MSDs) has been reported in the construction sector. The use of ladders in the workplace has long been identified as a significant risk that can lead to workplace accidents. However, it is unclear if platform types have an effect on the physical risk factors for MSDs in overhead work. The aim of this study is to perform a pilot study on the effects of hand activity on both shoulder muscle loading and task performance while working on ladders versus Mobile Elevated Working Platforms (MEWPs). It is hypothesised that work on ladders would result in greater muscle loading demands, increased levels of discomfort, and reduced performance due to the restrictions on postures that could be adopted. A field study (n = 19) of experienced electricians on a construction site found that workers spent approximately 28% of their working time on ladders versus 6% on MEWPs. However, the durations of individual tasks were higher on MEWPs (153 s) than on ladders (73 s). Additionally, maximum levels of perceived discomfort (on a VAS 0-100) were reported for the shoulders (27), neck (23), and lower regions of the body (22). A simulated study (n = 12) found that task performance and discomfort were not significantly different between platform types (ladder vs. MEWP) when completing either of three tasks: cabling, assembly and drilling. However, platform and task had significant effects (p Ergonomics Society. All rights reserved.

  11. Ladder Operators for Lamé Spheroconal Harmonic Polynomials

    Directory of Open Access Journals (Sweden)

    Ricardo Méndez-Fragoso


    Full Text Available Three sets of ladder operators in spheroconal coordinates and their respective actions on Lamé spheroconal harmonic polynomials are presented in this article. The polynomials are common eigenfunctions of the square of the angular momentum operator and of the asymmetry distribution Hamiltonian for the rotations of asymmetric molecules, in the body-fixed frame with principal axes. The first set of operators for Lamé polynomials of a given species and a fixed value of the square of the angular momentum raise and lower and lower and raise in complementary ways the quantum numbers $n_1$ and $n_2$ counting the respective nodal elliptical cones. The second set of operators consisting of the cartesian components $hat L_x$, $hat L_y$, $hat L_z$ of the angular momentum connect pairs of the four species of polynomials of a chosen kind and angular momentum. The third set of operators, the cartesian components $hat p_x$, $hat p_y$, $hat p_z$ of the linear momentum, connect pairs of the polynomials differing in one unit in their angular momentum and in their parities. Relationships among spheroconal harmonics at the levels of the three sets of operators are illustrated.

  12. The incidence and burden of ladder, structure, and scaffolding falls. (United States)

    Diggs, Brian S; Lenfesty, Barbara; Arthur, Melanie; Hedges, Jerris R; Newgard, Craig D; Mullins, Richard J


    The national morbidity and mortality associated with falls from a height is incompletely described. The authors estimated the rates of injury, hospitalization, and mortality due to these falls for subgroups of the U.S. population. Administrative databases (1995-2000) provided national samples of patients treated for injuries following a fall from a height (ICD-9-CM E-codes E881.0, E881.1, or E882). Inpatient data are from the Nationwide Inpatient Sample, and emergency department data are from the National Hospital Ambulatory Medical Care Survey. A total of 347,484 (95% confidence interval = 308,417 to 386,551) emergency department presentations occur annually for injuries following a fall. Hospitalized patients older than 75 years of age had a 3.3% case fatality, and 42% were discharged to a skilled nursing facility. For patients older than 55 years of age, 86% of falls were not work related. Ladder and structure falls by elders are a substantial emergency department problem warranting thorough clinical evaluation and injury prevention efforts.

  13. Apollo 11 Astronaut Neil Armstrong Performs Ladder Practice (United States)


    In preparation of the nation's first Lunar landing mission, Apollo 11 crew members underwent training activities to practice activities they would be performing during the mission. In this photograph, Neil Armstrong, donned in his space suit, practices getting back to the first rung of the ladder on the Lunar Module (LM). The Apollo 11 mission launched from the Kennedy Space Center (KSC) in Florida via the Marshall Space Flight Center (MSFC) developed Saturn V launch vehicle on July 16, 1969 and safely returned to Earth on July 24, 1969. Aboard the space craft were astronauts Neil A. Armstrong, commander; Michael Collins, Command Module (CM) pilot; and Edwin E. (Buzz) Aldrin Jr., Lunar Module (LM) pilot. The CM, 'Columbia', piloted by Collins, remained in a parking orbit around the Moon while the LM, 'Eagle'', carrying astronauts Armstrong and Aldrin, landed on the Moon. On July 20, 1969, Armstrong was the first human to ever stand on the lunar surface, followed by Aldrin. During 2½ hours of surface exploration, the crew collected 47 pounds of lunar surface material for analysis back on Earth. With the success of Apollo 11, the national objective to land men on the Moon and return them safely to Earth had been accomplished.

  14. Spin-1/2 Heisenberg ladder: variation of entanglement and fidelity measures close to quantum critical points


    Tribedi, Amit; Bose, Indrani


    We consider a two-chain, spin-1/2 antiferromagnetic Heisenberg spin ladder in an external magnetic field H. The spin ladder is known to undergo second order quantum phase transitions (QPTs) at two critical values, Hc1 and Hc2, of the magnetic field. There are now known examples of strongly coupled (rung exchange interaction much stronger than nearest-neighbour intrachain exchange interaction) organic ladder compounds in which QPTs have been experimentally observed. In this paper, we investiga...

  15. A one-dimensional ladder-like coordination polymer: poly[[hexa-aqua-bis(μ-5-nitro-benzene-1,3-dicarboxyl-ato-κO,O',O'')(μ-oxalato-κO,O':O'',O''')diyttrium(III)] trihydrate]. (United States)

    Fu, Zhong; Lin, Ying; Zhou, Yun-You; Zhang, Hong-Tao


    In the crystal structure of the title one-dimensional coordination polymer, [Y(2)(C(8)H(3)NO(6))(2)(C(2)O(4))(H(2)O)(6)]·3H(2)O, each Y(III) ion is bridged to its neighbours by two 5-nitro-benzene-1,3-dicarboxyl-ate (nbdc) dianions and one oxalate dianion (located on an inversion centre) to form a ladder-like polymeric structure. The two carboxylate groups of nbdc assume different modes of coordination, one is chelating whereas the other is monodentate. Three water mol-ecules coordinate to the Y(III) ion to complete an eight-coordinate distorted dodecahedral geometry. The ladder-like polymers are assembled together by hydrogen bonding and π-π stacking [centrio-centriod distance = 3.819 (9) Å] in the crystal structure.

  16. Nitric oxide triggers a concentration-dependent differential modulation of superoxide dismutase (FeSOD and Cu/ZnSOD) activity in sunflower seedling roots and cotyledons as an early and long distance signaling response to NaCl stress. (United States)

    Arora, Dhara; Bhatla, Satish C


    Dark-grown sunflower (Helianthus annuus L.) seedlings exhibit modulation of total superoxide dismutase (SOD;EC activity in roots and cotyledons (10,000g supernatant) in response to salt stress (NaCl; 120 mM) through a differential, zymographically detectable, whole tissue activity of FeSOD and Cu/ZnSOD. Confocal laser scanning microscopic imaging (CLSM) has further shown that NaCl stress significantly influences differential spatial distribution of Cu/ZnSOD and MnSOD isoforms in an inverse manner. Dual action of nitric oxide (NO) is evident in its crosstalk with FeSOD and Cu/ZnSOD in seedling roots and cotyledons in control and NaCl(-) stress conditions. Cu/ZnSOD activity in the roots of 2 d old NaCl(-) stressed seedlings is enhanced in the presence of 125-1000 µM of NO donor (sodium nitroprusside; SNP) indicating salt sensitivity of the enzyme activity. Quenching of endogenous NO by cPTIO treatment (500, 1000 µM) lowers FeSOD activity in roots (-NaCl). Cotyledons from control seedlings show an upregulation of FeSOD activity with increasing availability of SNP (125-1000 µM) in the Hoagland irrigation medium. Quenching of NO by cPTIO provides evidence for an inverse correlation between NO availability and FeSOD activity in seedling cotyledons irrespective of NaCl stress. Variable response due to NO on SOD isoforms in sunflower seedlings reflects its concentration-dependent biphasic (pro- and antioxidant) nature of action. Differential induction of SOD isoforms by NO indicates separate intracellular signaling pathways (associated with their respective functional separation) operative in seedling roots as an early salt stress mechanism and in cotyledons as an early long-distance NaCl stress sensing mechanism.

  17. Asparagine and glutamine ladders promote cross-species prion conversion. (United States)

    Kurt, Timothy D; Aguilar-Calvo, Patricia; Jiang, Lin; Rodriguez, José A; Alderson, Nazilla; Eisenberg, David S; Sigurdson, Christina J


    Prion transmission between species is governed in part by primary sequence similarity between the infectious prion aggregate, PrP Sc , and the cellular prion protein of the host, PrP C A puzzling feature of prion formation is that certain PrP C sequences, such as that of bank vole, can be converted by a remarkably broad array of different mammalian prions, whereas others, such as rabbit, show robust resistance to cross-species prion conversion. To examine the structural determinants that confer susceptibility or resistance to prion conversion, we systematically tested over 40 PrP C variants of susceptible and resistant PrP C sequences in a prion conversion assay. Five key residue positions markedly impacted prion conversion, four of which were in steric zipper segments where side chains from amino acids tightly interdigitate in a dry interface. Strikingly, all five residue substitutions modulating prion conversion involved the gain or loss of an asparagine or glutamine residue. For two of the four positions, Asn and Gln residues were not interchangeable, revealing a strict requirement for either an Asn or Gln residue. Bank voles have a high number of Asn and Gln residues and a high Asn:Gln ratio. These findings suggest that a high number of Asn and Gln residues at specific positions may stabilize β-sheets and lower the energy barrier for cross-species prion transmission, potentially because of hydrogen bond networks from side chain amides forming extended Asn/Gln ladders. These data also suggest that multiple PrP C segments containing Asn/Gln residues may act in concert along a replicative interface to promote prion conversion. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  18. Model Comparison Exercise Circuit Training Game and Circuit Ladder Drills to Improve Agility and Speed

    Directory of Open Access Journals (Sweden)

    Susilaturochman Hendrawan Koestanto


    Full Text Available The purpose of this study was to compare: (1 the effect of circuit training game and circuit ladder drill for the agility; (2 the effect of circuit training game and circuit ladder drill on speed; (3 the difference effect of circuit training game and circuit ladder drill for the speed (4 the difference effect of circuit training game and circuit ladder drill on agility. The type of this research was quantitative with quasi-experimental methods. The design of this research was Factorial Design, with analysing data using ANOVA. The process of data collection was done by using 30 meters sprint speed test and shuttle run test during the pretest and posttest. Furthermore, the data was analyzed by using SPSS 22.0 series. Result: The circuit training game exercise program and circuit ladder drill were significant to increase agility and speed (sig 0.000 < α = 0.005 Group I, II, III had significant differences (sig 0.000 < α = 0.005. The mean of increase in speed of group I = 0.20 seconds, group II = 0.31 seconds, and group III = 0.11 seconds. The average increase agility to group I = 0.34 seconds group II = 0.60 seconds, group III = 0.13 seconds. Based on the analysis above, it could be concluded that there was an increase in the speed and agility of each group after being given a training.

  19. Doped spin ladders under magnetic field; Echelles de spins dopees sous champ magnetique

    Energy Technology Data Exchange (ETDEWEB)

    Roux, G


    This thesis deals with the physics of doped two-leg ladders which are a quasi one-dimensional and unconventional superconductor. We particularly focus on the properties under magnetic field. Models for strongly correlated electrons on ladders are studied using exact diagonalization and density-matrix renormalization group (DMRG). Results are also enlightened by using the bosonization technique. Taking into account a ring exchange it highlights the relation between the pairing of holes and the spin gap. Its influence on the dynamics of the magnetic fluctuations is also tackled. Afterwards, these excitations are probed by the magnetic field by coupling it to the spin degree of freedom of the electrons through Zeeman effect. We show the existence of doping-dependent magnetization plateaus and also the presence of an inhomogeneous superconducting phase (FFLO phase) associated with an exceeding of the Pauli limit. When a flux passes through the ladder, the magnetic field couples to the charge degree of freedom of the electrons via orbital effect. The diamagnetic response of the doped ladder probes the commensurate phases of the t-J model at low J/t. Algebraic transverse current fluctuations are also found once the field is turned on. Lastly, we report numerical evidences of a molecular superfluid phase in the 3/2-spin attractive Hubbard model: at a density low enough, bound states of four fermions, called quartets, acquire dominant superfluid fluctuations. The observed competition between the superfluid and density fluctuations is connected to the physics of doped ladders. (author)

  20. Groundstate fidelity phase diagram of the fully anisotropic two-leg spin-½ XXZ ladder (United States)

    Li, Sheng-Hao; Shi, Qian-Qian; Batchelor, Murray T.; Zhou, Huan-Qiang


    The fully anisotropic two-leg spin-\\tfrac{1}{2} XXZ ladder model is studied in terms of an algorithm based on the tensor network (TN) representation of quantum many-body states as an adaptation of projected entangled pair states to the geometry of translationally invariant infinite-size quantum spin ladders. The TN algorithm provides an effective method to generate the groundstate wave function, which allows computation of the groundstate fidelity per lattice site, a universal marker to detect phase transitions in quantum many-body systems. The groundstate fidelity is used in conjunction with local order and string order parameters to systematically map out the groundstate phase diagram of the ladder model. The phase diagram exhibits a rich diversity of quantum phases. These are the ferromagnetic, stripe ferromagnetic, rung singlet, rung triplet, Néel, stripe Néel and Haldane phases, along with the two XY phases XY1 and XY2.

  1. Effect of sieving polymer concentration on separation of 100 bp DNA Ladder by capillary gel electrophoresis (United States)

    Nakazumi, T.; Hara, Y.


    We studied the effect of sieving polymer concentration on separation of a 100 bp DNA Ladder by capillary gel electrophoresis (CGE) using hydroxyethyl cellulose (HEC) with a molecular size of 1000 k. For measurement purposes, we selected a fused silica capillary with total length of 15 cm and effective length of 7.5 cm; this was applied to compact CGE equipment for a Point-Care-Testing (POCT) system. Measurement results of the 100 bp DNA Ladder sample indicated that small DNA separation was significantly affected by HEC sieving polymer concentration. This was due to the level of entanglement between small DNA molecules and the sieving polymer chain significantly influencing migration time, mobility, and resolution length of the CGE process. We concluded that 1.0 w/v % HEC sieving polymer concentration was optimal for CGE separation of DNA ≥1000bp in the 100 bp DNA Ladder (100–1500 bp) when using the short-length capillary.

  2. 49 CFR 214.519 - Floors, decks, stairs, and ladders of on-track roadway maintenance machines. (United States)


    ... roadway maintenance machines. 214.519 Section 214.519 Transportation Other Regulations Relating to... SAFETY On-Track Roadway Maintenance Machines and Hi-Rail Vehicles § 214.519 Floors, decks, stairs, and ladders of on-track roadway maintenance machines. Floors, decks, stairs, and ladders of on-track roadway...

  3. Trees and ladders: A critique of the theory of human cognitive and behavioural evolution in Palaeolithic archaeology

    NARCIS (Netherlands)

    Langbroek, M.


    The modern biological model of (human) evolution is that of a branching tree. By contrast, prevailing models for human cognitive evolution remain unilinear in character, representing a ladder. The linear ladder model is the result of the opposition of an ethnographic and a primate reference frame

  4. Optical probing of anisotropic heat transport in the quantum spin ladder Ca9La5Cu24O41

    NARCIS (Netherlands)

    Otter, M.; Athanasopoulos, G.; Hlubek, N.; Montagnese, M.; Labois, M.; Fishman, D. A.; de Haan, F.; Singh, S.; Lakehal, D.; Giapintzakis, J.; Hess, C.; Revcolevschi, A.; van Loosdrecht, P. H. M.

    A transient thermal imaging technique is used to monitor heat diffusion at the surface of the antiferromagnetic spin ladder material Ca9La5Cu24O41. This material shows highly anisotropic thermal conductivity due to a large uni-directional magnetic heat transport along the ladders. The thermal

  5. Simulation of TunneLadder Traveling-Wave Tube Input/Output Coupler Characteristics Using MAFIA (United States)

    Kory, Carol L.; Qureshi, A. Haq


    RF input/output coupler characteristics for the TunneLadder traveling-wave tube have been calculated using the three-dimensional computer code, MAFIA and compared to experimental data with good agreement. Theory behind coupling of the TunneLadder interaction circuit to input and output waveguides is presented and VSWR data is calculated for variations on principal coupler dimensions to provide insight into manufacturing tolerances necessary for acceptable performance. Accuracy of results using MAFIA demonstrates how experimental hardware testing of three-dimensional coupler designs can be reduced.

  6. Explaining choice option attractiveness by beliefs elicited by the laddering method

    DEFF Research Database (Denmark)

    Grunert, Klaus G.; Bech-Larsen, Tino


    option. The laddering method is used to elicit beliefs of all three types for a choice between conventional and organic pork. As a benchmark, beliefs were also elicited in the traditional way advocated by Ajzen and Fishbein. Using both sets of beliefs in a subsequent survey, it was shown that the beliefs...... elicited by the laddering method increase explanatory power with regard to choice option attractiveness beyond the beliefs elicited by the Ajzen and Fishbein method, and that this additional explanatory power was due to those beliefs which relate the choice option to concepts with a higher level...

  7. Social interaction distance and stratification. (United States)

    Bottero, Wendy; Prandy, Kenneth


    There have been calls from several sources recently for a renewal of class analysis that would encompass social and cultural, as well as economic elements. This paper explores a tradition in stratification that is founded on this idea: relational or social distance approaches to mapping hierarchy and inequality which theorize stratification as a social space. The idea of 'social space' is not treated as a metaphor of hierarchy nor is the nature of the structure determined a priori. Rather, the space is identified by mapping social interactions. Exploring the nature of social space involves mapping the network of social interaction--patterns of friendship, partnership and cultural similarity--which gives rise to relations of social closeness and distance. Differential association has long been seen as the basis of hierarchy, but the usual approach is first to define a structure composed of a set of groups and then to investigate social interaction between them. Social distance approaches reverse this, using patterns of interaction to determine the nature of the structure. Differential association can be seen as a way of defining proximity within a social space, from the distances between social groups, or between social groups and social objects (such as lifestyle items). The paper demonstrates how the very different starting point of social distance approaches also leads to strikingly different theoretical conclusions about the nature of stratification and inequality.

  8. Thermoelectric Properties of Solution-Processed n-Doped Ladder-Type Conducting Polymers

    DEFF Research Database (Denmark)

    Wang, Suhao; Sun, Hengda; Ail, Ujwala


    Ladder-type "torsion-free" conducting polymers (e.g., polybenzimidazobenzophenanthroline (BBL)) can outperform "structurally distorted" donor-acceptor polymers (e.g., P(NDI2OD-T2)), in terms of conductivity and thermoelectric power factor. The polaron delocalization length is larger in BBL than...


    Directory of Open Access Journals (Sweden)

    Eka Pra Setiawati


    Full Text Available Vocabulary is an essential component in learning English. It influences four English skills; they are listening, speaking, reading, and writing, for getting a good result in English. In teaching learning process, the teacher often implements the less interesting method, technique, or even media of vocabulary mastery in teaching and learning process which make the students to be bored, inactive, an uniterested in memorizing English vocabulary. Some media can be interested as the solutions in vocabulary mastery, they are Snake Ladders media and Scrabble media. The investigation was undergone by quantitative research. The researcher applied experimental research. This research underwent pre-test post-test control group design. To analyze data, t-test formula is used to measure the result of collected data. From the t-test measurement, it showed that t-test is 3.15 and t-table is 2.66. It means that t-hit > t-table. Based on the collected data, there is different result of using Snake Ladders from Scrabble media toward students’ vocabulary mastery. It was found that the students who are taught by using Snake Ladders resulted significant outcome than those are instructed by Scrabble media. It means that Snake Ladders is effective to improve the students’ vocabulary mastery.

  10. ABC of ladder operators for rationally extended quantum harmonic oscillator systems (United States)

    Cariñena, José F.; Plyushchay, Mikhail S.


    The problem of construction of ladder operators for rationally extended quantum harmonic oscillator (REQHO) systems of a general form is investigated in the light of existence of different schemes of the Darboux-Crum-Krein-Adler transformations by which such systems can be generated from the quantum harmonic oscillator. Any REQHO system is characterized by the number of separated states in its spectrum, the number of ‘valence bands’ in which the separated states are organized, and by the total number of the missing energy levels and their position. All these peculiarities of a REQHO system are shown to be detected and reflected by a trinity (A^+/- , B^+/- , C^+/-) of the basic (primary) lowering and raising ladder operators related between themselves by certain algebraic identities with coefficients polynomially-dependent on the Hamiltonian. We show that all the secondary, higher-order ladder operators are obtainable by a composition of the basic ladder operators of the trinity which form the set of the spectrum-generating operators. Each trinity, in turn, can be constructed from the intertwining operators of the two complementary minimal schemes of the Darboux-Crum-Krein-Adler transformations.

  11. Entrepreneurial Progress: Climbing The Entrepreneurial Ladder in Europe and The US

    NARCIS (Netherlands)

    P.W. van der Zwan (Peter); I. Verheul (Ingrid); A.R. Thurik (Roy); I. Grilo (Isabel)


    textabstractWe investigate which countries have the highest potential to achieve entrepreneurial progress. This progress is defined using an entrepreneurial ladder with five successive steps: “never thought about starting a business”, “thinking about starting a business”, “taking steps to start a

  12. Laughlin-like States in Bosonic and Fermionic Atomic Synthetic Ladders

    Directory of Open Access Journals (Sweden)

    Marcello Calvanese Strinati


    Full Text Available The combination of interactions and static gauge fields plays a pivotal role in our understanding of strongly correlated quantum matter. Cold atomic gases endowed with a synthetic dimension are emerging as an ideal platform to experimentally address this interplay in quasi-one-dimensional systems. A fundamental question is whether these setups can give access to pristine two-dimensional phenomena, such as the fractional quantum Hall effect, and how. We show that unambiguous signatures of bosonic and fermionic Laughlin-like states can be observed and characterized in synthetic ladders. We theoretically diagnose these Laughlin-like states focusing on the chiral current flowing in the ladder, on the central charge of the low-energy theory, and on the properties of the entanglement entropy. Remarkably, Laughlin-like states are separated from conventional liquids by Lifschitz-type transitions, characterized by sharp discontinuities in the current profiles, which we address using extensive simulations based on matrix-product states. Our work provides a qualitative and quantitative guideline towards the observability and understanding of strongly correlated states of matter in synthetic ladders. In particular, we unveil how state-of-the-art experimental settings constitute an ideal starting point to progressively tackle two-dimensional strongly interacting systems from a ladder viewpoint, opening a new perspective for the observation of non-Abelian states of matter.

  13. Commutation-relation-preserving ladder operators for propagating optical fields in nonuniform lossy media

    DEFF Research Database (Denmark)

    Partanen, Mikko; Häyrynen, Teppo; Tulkki, Jukka


    We have recently developed a quantized fluctuational electrodynamics (QFED) formalism to describe the quantum aspects of local thermal balance formation and to formulate the electromagnetic field ladder operators so that they no longer exhibit the anomalies reported for resonant structures. Here we...

  14. Evaluation Practice and Theory: Up and down the Ladder of Abstraction (United States)

    Leviton, Laura C.


    Debra Rog presented the 2014 Eleanor Chelimsky Forum address, offering ways to integrate evaluation theory and practice by abundant use of practice examples. These examples illustrate the effective use of the Ladder of Abstraction from semantics, working from the concrete to the abstract and back again.

  15. The climate learning ladder. A pragmatic procedure to support climate adaptation

    NARCIS (Netherlands)

    Werners, S.E.; Tabara, J.D.; Gensuo, J.; McEvoy, D.; Dai, X.Q.; Neufeldt, H.; West, J.; Serra, A.


    We introduce a new pragmatic procedure called the climate learning ladder to structure policy analysis, support reflection and identify critical decisions to support climate adaptation. This tool is the result of the reflexive learning process that occurred while developing innovative appraisal

  16. Astronaut Edwin Aldrin descends steps of Lunar Module ladder to walk on moon (United States)


    Astronaut Edwin E. Aldrin Jr., lunar module pilot, descends the steps of the Lunar Module (LM) ladder as he prepares to walk on the Moon. He had just egressed the LM. This picture was taken by Astronaut Neil A. Armstrong, commander, with a 70mm lunar surface camera.

  17. Means-end chains and laddering: An inventory of problems and an agenda for research

    DEFF Research Database (Denmark)

    Grunert, Klaus G.; Grunert, Suzanne C.; Sørensen, Elin

    Executive summary 1. Means-end chains are a device used to understand how consumers mentally link products to self-relevant consequences. Means-end chains are usually measured by a method called laddering. 2. Means-end chains may fall short of tapping all relevant aspects of how consumers think a...

  18. Chemodiversity of Ladder-Frame Prymnesin Polyethers in Prymnesium parvum

    DEFF Research Database (Denmark)

    Rasmussen, Silas Anselm; Meier, Sebastian; Andersen, Nikolaj Gedsted


    Blooms of the microalga Prymnesium parvum cause devastating fish kills worldwide, which are suspected to be caused by the supersized ladder-frame polyether toxins prymnesin-1 and -2. These toxins have, however, only been detected from P. parvum in rare cases since they were originally described two...

  19. Parents' Participation on School Councils Analysed through Arnstein's Ladder of Participation (United States)

    Stelmach, Bonnie


    Although parent school councils are the archetypal arrangement for engaging parents in school improvement planning, their effectiveness is negligible when it comes to building parents' capacity for and confidence in educational decision-making. Using Arnstein's ladder of citizen participation, this qualitative case study investigated the nature…

  20. Role of Modular Polyketide Synthases in the Production of Polyether Ladder Compounds in Ciguatoxin-Producing Gambierdiscus polynesiensis and G. excentricus (Dinophyceae). (United States)

    Kohli, Gurjeet S; Campbell, Katrina; John, Uwe; Smith, Kirsty F; Fraga, Santiago; Rhodes, Lesley L; Murray, Shauna A


    Gambierdiscus, a benthic dinoflagellate, produces ciguatoxins that cause the human illness Ciguatera. Ciguatoxins are polyether ladder compounds that have a polyketide origin, indicating that polyketide synthases (PKS) are involved in their production. We sequenced transcriptomes of Gambierdiscus excentricus and Gambierdiscus polynesiensis and found 264 contigs encoding single domain ketoacyl synthases (KS; G. excentricus: 106, G. polynesiensis: 143) and ketoreductases (KR; G. excentricus: 7, G. polynesiensis: 8) with sequence similarity to type I PKSs, as reported in other dinoflagellates. In addition, 24 contigs (G. excentricus: 3, G. polynesiensis: 21) encoding multiple PKS domains (forming typical type I PKSs modules) were found. The proposed structure produced by one of these megasynthases resembles a partial carbon backbone of a polyether ladder compound. Seventeen contigs encoding single domain KS, KR, s-malonyltransacylase, dehydratase and enoyl reductase with sequence similarity to type II fatty acid synthases (FAS) in plants were found. Type I PKS and type II FAS genes were distinguished based on the arrangement of domains on the contigs and their sequence similarity and phylogenetic clustering with known PKS/FAS genes in other organisms. This differentiation of PKS and FAS pathways in Gambierdiscus is important, as it will facilitate approaches to investigating toxin biosynthesis pathways in dinoflagellates. © 2017 The Author(s) Journal of Eukaryotic Microbiology © 2017 International Society of Protistologists.

  1. Effects of aluminum trichloride and magnesium chloride on the synthesis of ladder polyphenylsilsesquioxane

    Directory of Open Access Journals (Sweden)

    Jiang Yunyun


    Full Text Available Ladder polyphenylsilsesquioxane (Ph-LPSQ has been synthesized at 80°C through the hydrolysis and condensation of phenyltrichlorosilane (PhSiCl3, with aluminum chloride (AlCl3 or magnesium chloride (MgCl2 as an assistant reactant. The Ph-LPSQ obtained has been characterized and analyzed by SEM, FTIR, TGA, 29Si NMR, and MALDI-TOF MS, and the effects of AlCl3and MgCl2on the structure regularity of Ph-LPSQ and the condensation polymerizationhavealso been studied. The results showed that Ph-LPSQ could be obtained in theAlCl3and MgCl2systems, respectively, but the experimental phenomena and results showed significant differences between the two systems. SEM observation revealed spherical Ph-LPSQ particles from the PhSiCl3/AlCl3system, but irregular and agglomerated Ph-LPSQ particles from the PhSiCl3/1.5(MgCl2 system. TGA, 29SiNMR, and MALDI-TOF MS indicated that the ladder structure of Ph-LPSQ from the PhSiCl3/1.5(MgCl2 system was more regular. Inthe PhSiCl3/AlCl3system, Al could be incorporated into the ladder chain structure through competing reactions between Si-O-Al and Si-O-Si, which slightly decreased the regularity of the ladder chain structure of Ph-LPSQ. Mechanistic analysis suggests that the presence of AlCl3or MgCl2in the hydrolysis and condensation system favors the intermolecular condensation of intermediate products of polyhydroxyl silanol to form a regular ladder structure.

  2. Adaptation of a ladder beam walking task to assess locomotor recovery in mice following spinal cord injury (United States)

    Cummings, Brian J.; Engesser-Cesar, Christie; Anderson, Aileen J.


    Locomotor impairments after spinal cord injury (SCI) are often assessed using open-field rating scales. These tasks have the advantage of spanning the range from complete paralysis to normal walking; however, they lack sensitivity at specific levels of recovery. Additionally, most supplemental assessments were developed in rats, not mice. For example, the horizontal ladder beam has been used to measure recovery in the rat after SCI. This parametric task results in a videotaped archival record of the event, is easily administered, and is unambiguously scored. Although a ladder beam apparatus for mice is available, its use in the assessment of recovery in SCI mice is rare, possibly because normative data for uninjured mice and the type of step misplacements injured mice exhibit is lacking. We report the development of a modified ladder beam instrument and scoring system to measure hindlimb recovery in vertebral T9 contusion spinal cord injured mice. The mouse ladder beam allows for the use of standard parametric statistical tests to assess locomotor recovery. Ladder beam performance is consistent across four strains of mice, there are no sex differences, and inter-rater reliability between observers is high. The ladder beam score is proportional to injury severity and can be used to easily separate mice capable of weight-supported stance up to mice with consistent forelimb to hindlimb coordination. Critically, horizontal ladder beam testing discriminates between mice that score identically in terms of stepping frequency in open-field testing. PMID:17197044

  3. Use of portable ladders - field observations and self-reported safety performance in the cable TV industry. (United States)

    Chang, Wen-Ruey; Huang, Yueng-Hsiang; Brunette, Christopher; Lee, Jin


    Portable ladders incidents remain a major cause of falls from heights. This study reported field observations of environments, work conditions and safety behaviour involving portable ladders and their correlations with self-reported safety performance. Seventy-five professional installers of a company in the cable and other pay TV industry were observed for 320 ladder usages at their worksites. The participants also filled out a questionnaire to measure self-reported safety performance. Proper setup on slippery surfaces, correct method for ladder inclination setup and ladder secured at the bottom had the lowest compliance with best practices and training guidelines. The observation compliance score was found to have significant correlation with straight ladder inclined angle (Pearson's r = 0.23, p self-reported safety participation (r = 0.29, p < 0.01). The results provide a broad perspective on employees' safety compliance and identify areas for improving safety behaviours. Practitioner Summary: A checklist was used while observing professional installers of a cable company for portable ladder usage at their worksites. Items that had the lowest compliance with best practices and training guidelines were identified. The results provide a broad perspective on employees' safety compliance and identify areas for improving safety behaviours.

  4. Encyclopedia of distances

    CERN Document Server

    Deza, Michel Marie


    This 4th edition of the leading reference volume on distance metrics is characterized by updated and rewritten sections on some items suggested by experts and readers, as well a general streamlining of content and the addition of essential new topics. Though the structure remains unchanged, the new edition also explores recent advances in the use of distances and metrics for e.g. generalized distances, probability theory, graph theory, coding theory, data analysis. New topics in the purely mathematical sections include e.g. the Vitanyi multiset-metric, algebraic point-conic distance, triangular ratio metric, Rossi-Hamming metric, Taneja distance, spectral semimetric between graphs, channel metrization, and Maryland bridge distance. The multidisciplinary sections have also been supplemented with new topics, including: dynamic time wrapping distance, memory distance, allometry, atmospheric depth, elliptic orbit distance, VLBI distance measurements, the astronomical system of units, and walkability distance. Lea...

  5. Distance Estimation in Cities (United States)

    Canter, David; Tagg, Stephen K.


    The results of eleven distance estimation studies made in seven cities and five countries are reported. Distances were estimated between various points within the cities in which the subjects were resident. In general, undergraduate residents' distance estimates correlated highly with actual distance, but the nonundergraduate group's did not.…

  6. Representations of distance

    DEFF Research Database (Denmark)

    Larsen, Gunvor Riber


    This paper explores how Danish tourists represent distance in relation to their holiday mobility and how these representations of distance are a result of being aero-mobile as opposed to being land-mobile. Based on interviews with Danish tourists, whose holiday mobility ranges from the European...... continent to global destinations, the first part of this qualitative study identifies three categories of representations of distance that show how distance is being ‘translated’ by the tourists into non-geometric forms: distance as resources, distance as accessibility, and distance as knowledge....... The representations of distance articulated by the Danish tourists show that distance is often not viewed in ‘just’ kilometres. Rather, it is understood in forms that express how transcending the physical distance through holiday mobility is dependent on individual social and economic contexts, and on whether...

  7. The Distance Standard Deviation


    Edelmann, Dominic; Richards, Donald; Vogel, Daniel


    The distance standard deviation, which arises in distance correlation analysis of multivariate data, is studied as a measure of spread. New representations for the distance standard deviation are obtained in terms of Gini's mean difference and in terms of the moments of spacings of order statistics. Inequalities for the distance variance are derived, proving that the distance standard deviation is bounded above by the classical standard deviation and by Gini's mean difference. Further, it is ...

  8. Encyclopedia of distances

    CERN Document Server

    Deza, Michel Marie


    This updated and revised third edition of the leading reference volume on distance metrics includes new items from very active research areas in the use of distances and metrics such as geometry, graph theory, probability theory and analysis. Among the new topics included are, for example, polyhedral metric space, nearness matrix problems, distances between belief assignments, distance-related animal settings, diamond-cutting distances, natural units of length, Heidegger’s de-severance distance, and brain distances. The publication of this volume coincides with intensifying research efforts into metric spaces and especially distance design for applications. Accurate metrics have become a crucial goal in computational biology, image analysis, speech recognition and information retrieval. Leaving aside the practical questions that arise during the selection of a ‘good’ distance function, this work focuses on providing the research community with an invaluable comprehensive listing of the main available di...

  9. Implantable bladder volume sensor based on resistor ladder network composed of conductive hydrogel composite. (United States)

    Mi Kyung Kim; Hyojung Kim; Jung, Yeon Su; Adem, Kenana M A; Bawazir, Sarah S; Stefanini, Cesare; Lee, Hyunjoo J


    An accurate bladder volume monitoring system is a critical component in diagnosis and treatment of urological disorders. Here, we report an implantable bladder volume sensor with a multi-level resistor ladder which estimates the bladder volume through discrete resistance values. Discretization allows the sensor output to be resilient to the long-term drift, hysteresis, and degradation of the sensor materials. Our sensor is composed of biocompatible polypyrrole/agarose hydrogel composite. Because Young's modulus of this composite is comparable to that of the bladder wall, the effect of mechanical loading of the sensor on the bladder movement is minimized which allows more accurate volume monitoring. We also demonstrate the patterning and molding capability of this material by fabrication various structures. Lastly, we successfully demonstrate the functionality of the multi-level resistor ladder sensor as a bladder volume sensor by attaching the sensor on the pig's bladder and observing the impedance change of the sensor.

  10. 4-bit digital to analog converter using R-2R ladder and binary weighted resistors (United States)

    Diosanto, J.; Batac, M. L.; Pereda, K. J.; Caldo, R.


    The use of a 4-bit digital-to-analog converter using two methods; Binary Weighted Resistors and R-2R Ladder is designed and presented in this paper. The main components that were used in constructing both circuits were different resistor values, operational amplifier (LM741) and single pole double throw switches. Both circuits were designed using MULTISIM software to be able to test the circuit for its ideal application and FRITZING software for the layout designing and fabrication to the printed circuit board. The implementation of both systems in an actual circuit benefits in determining and comparing the advantages and disadvantages of each. It was realized that the binary weighted circuit is more efficient DAC, having lower percentage error of 0.267% compared to R-2R ladder circuit which has a minimum of percentage error of 4.16%.

  11. Controlling Luttinger liquid physics in spin ladders under a magnetic field. (United States)

    Klanjsek, M; Mayaffre, H; Berthier, C; Horvatić, M; Chiari, B; Piovesana, O; Bouillot, P; Kollath, C; Orignac, E; Citro, R; Giamarchi, T


    We present a 14N nuclear magnetic resonance study of a single crystal of CuBr4(C5H12N)2 (BPCB) consisting of weakly coupled spin-1/2 Heisenberg antiferromagnetic ladders. Treating ladders in the gapless phase as Luttinger liquids, we are able to fully account for (i) the magnetic field dependence of the nuclear spin-lattice relaxation rate T1(-1) at 250 mK and for (ii) the phase transition to a 3D ordered phase occurring below 110 mK due to weak interladder exchange coupling. BPCB is thus an excellent model system where the possibility to control Luttinger liquid parameters in a continuous manner is demonstrated and the Luttinger liquid model tested in detail over the whole fermion band.

  12. One-particle versus two-particle crossover in weakly coupled Hubbard chains and ladders: perturbative renormalization group approach

    International Nuclear Information System (INIS)

    Kishine, Jun-Ichiro; Yonemitsu, Kenji


    Physical nature of dimensional crossovers in weakly coupled Hubbard chains and ladders has been discussed within the framework of the perturbative renormalization-group (PRG) approach. The difference between these two cases originates from different universality classes which the corresponding isolated systems belong to. In the present work, we discuss the nature of the dimensional crossovers in the weakly coupled chains and ladders, with emphasis on the difference between the two cases within the framework of the PRG approach. The difference of the universality class of the isolated chain and ladder profoundly affects the relevance or irrelevance of the inter-chain/ladder one-particle hopping. The strong coupling phase of the isolated ladder makes the one-particle process irrelevant so that the d-wave superconducting transition can be induced via the two-particle crossover in the weakly coupled ladders. The weak coupling phase of the isolated chain makes the one-particle process relevant so that the two-particle crossover can hardly be realized in the coupled chains. (Copyright (1998) World Scientific Publishing Co. Pte. Ltd)

  13. Star-shaped ladder-type ter(p-phenylene)s for efficient multiphoton absorption. (United States)

    Guo, Lei; Li, King Fai; Wong, Man Shing; Cheah, Kok Wai


    Star-shaped ladder-type ter(p-phenylene)s exhibit remarkably efficient multiphoton absorption properties with 2PA cross-section up to 2579 GM at 700 nm and 3PA cross-section up to 3.35 × 10(-76) cm(6) s(2) in the femtosecond regime for a blue-emissive molecule despite having such a short π-conjugated framework.

  14. Hydroxyl-substituted ladder polyethers via selective tandem epoxidation/cyclization sequence. (United States)

    Czabaniuk, Lara C; Jamison, Timothy F


    A new and highly selective method for the synthesis of hydroxyl-substituted tetrahydropyrans is described. This method utilizes titanium(IV) isopropoxide and diethyl tartrate to perform a diastereoselective epoxidation followed by in situ epoxide activation and highly selective endo-cyclization to form the desired tetrahydropyran ring. The HIJ ring fragment of the marine ladder polyether yessotoxin was synthesized using this two-stage tactic that proceeds with high efficiency and excellent regioselectivity.

  15. Modification of the Ladder Rung Walking Task?New Options for Analysis of Skilled Movements


    Antonow-Schlorke, Iwa; Ehrhardt, Julia; Knieling, Marcel


    Method sensitivity is critical for evaluation of poststroke motor function. Skilled walking was assessed in horizontal, upward, and downward rung ladder walking to compare the demands of the tasks and test sensitivity. The complete step sequence of a walk was subjected to analysis aimed at demonstrating the walking pattern, step sequence, step cycle, limb coordination, and limb interaction to complement the foot fault scoring system. Rats (males, n = 10) underwent unilateral photothrombotic l...

  16. Telecast of Astronaut Neil Armstrong descending ladder to surface of the moon (United States)


    Astronaut Neil A. Armstrong, Apollo 11 commander, descends the ladder of the Apollo 11 Lunar Module prior to making the first step by man on the moon. This view is a black and white reproduction taken from a telecast by the Apollo 11 lunar surface camera during extravehicular activity. The black bar running through the center of the picture is an anamoly in the television ground data system at the Goldstone Tracking Station.

  17. Telecast of Astronauts Armstrong and Aldrin by the Lunar Module ladder (United States)


    Astronauts Neil A. Armstrong (on left), commander; and Edwin E. Aldrin Jr., lunar module pilot, are seen standing by the Lunar Module ladder in this black and white reproduction taken from a telecast by the Apollo 11 lunar surface television camera during the Apollo 11 extravehicular activity. This picture was made from a televised image received at the Deep Space Network tracking station at Goldstone, California.

  18. “Why Caipirinha?”- The Online via Chat Laddering Technique CAN Answer

    Directory of Open Access Journals (Sweden)

    Bruno Bordeaux-Rego


    Full Text Available As customers are becoming increasingly connected to the internet, this means that they are available for online interviews, thus opening up a space for investigating research methods, especially qualitative research, in an attempt to identify how to adapt data collecting instruments to the so-called “connected customer era”. In this context, the focus of this article is on the application viability analysis of the laddering technique used online and in real-time chat by asking the following question: “Why caipirinha?”. Conducting online in-depth interviews through the MSN Messenger and Skype (the most commonly used chat tools in Brazil, 23 attributes, 22 consequences and 13 values were identified, resulting in 133 ladders, 71 of which reached the value level. Along with friends/mates, Integration, Entertainment and Fun, in addition to Alcohol, Insouciance/ relaxation and Pleasure constitute the most frequent ladders. Concerning the application itself, the participants gave positive feedback, even though some of them did not feel satisfied because they became tired. Convenience, objectivity, disinhibition, easy scheduling and flexibility were identified. The viability of online in-depth interviewing via real-time chats was confirmed, raising the question of the possibility of it achieving other qualitative research techniques.

  19. Investigation of electronic transport through a ladder-like graphene nanoribbon including random distributed impurities (United States)

    Esmaili, Esmat; Mardaani, Mohammad; Rabani, Hassan


    The electronic transport of a ladder-like graphene nanoribbon which the on-site or hopping energies of a small part of it can be random is modeled by using the Green's function technique within the nearest neighbor tight-binding approach. We employ a unitary transformation in order to convert the Hamiltonian of the nanoribbon to the Hamiltonian of a tight-binding ladder-like network. In this case, the disturbed part of the system includes the second neighbor hopping interactions. While, the converted Hamiltonian of each ideal part is equivalent to the Hamiltonian of two periodic on-site chains. Therefore, we can insert the self-energies of the alternative on-site tight-binding chains to the inverse of the Green's function matrix of the ladder-like part. In this viewpoint, the conductance is constructed from two trans and cis contributions. The results show that increasing the disorder strength causes the increase and decrease of the conductance of the trans and cis contributions, respectively.

  20. Modification of the ladder rung walking task-new options for analysis of skilled movements. (United States)

    Antonow-Schlorke, Iwa; Ehrhardt, Julia; Knieling, Marcel


    Method sensitivity is critical for evaluation of poststroke motor function. Skilled walking was assessed in horizontal, upward, and downward rung ladder walking to compare the demands of the tasks and test sensitivity. The complete step sequence of a walk was subjected to analysis aimed at demonstrating the walking pattern, step sequence, step cycle, limb coordination, and limb interaction to complement the foot fault scoring system. Rats (males, n = 10) underwent unilateral photothrombotic lesion of the motor cortex of the forelimb and hind limb areas. Locomotion was video recorded before the insult and at postischemic days 7 and 28. Analysis of walking was performed frame-by-frame. Walking along the rung ladder revealed different results that were dependent on ladder inclination. Horizontal walking was found to discriminate lesion-related motor deficits in forelimb, whereas downward walking demonstrates hind limb use most sensitively. A more frequent use of the impaired forelimb that possibly supported poststroke motor learning in rats was shown. The present study provides a novel system for a detailed analysis of the complete walking sequence and will help to provide a better understanding of how rats deal with motor impairments.

  1. Modification of the Ladder Rung Walking Task—New Options for Analysis of Skilled Movements

    Directory of Open Access Journals (Sweden)

    Iwa Antonow-Schlorke


    Full Text Available Method sensitivity is critical for evaluation of poststroke motor function. Skilled walking was assessed in horizontal, upward, and downward rung ladder walking to compare the demands of the tasks and test sensitivity. The complete step sequence of a walk was subjected to analysis aimed at demonstrating the walking pattern, step sequence, step cycle, limb coordination, and limb interaction to complement the foot fault scoring system. Rats (males, n=10 underwent unilateral photothrombotic lesion of the motor cortex of the forelimb and hind limb areas. Locomotion was video recorded before the insult and at postischemic days 7 and 28. Analysis of walking was performed frame-by-frame. Walking along the rung ladder revealed different results that were dependent on ladder inclination. Horizontal walking was found to discriminate lesion-related motor deficits in forelimb, whereas downward walking demonstrates hind limb use most sensitively. A more frequent use of the impaired forelimb that possibly supported poststroke motor learning in rats was shown. The present study provides a novel system for a detailed analysis of the complete walking sequence and will help to provide a better understanding of how rats deal with motor impairments.

  2. Modification of the Ladder Rung Walking Task—New Options for Analysis of Skilled Movements (United States)

    Antonow-Schlorke, Iwa; Ehrhardt, Julia; Knieling, Marcel


    Method sensitivity is critical for evaluation of poststroke motor function. Skilled walking was assessed in horizontal, upward, and downward rung ladder walking to compare the demands of the tasks and test sensitivity. The complete step sequence of a walk was subjected to analysis aimed at demonstrating the walking pattern, step sequence, step cycle, limb coordination, and limb interaction to complement the foot fault scoring system. Rats (males, n = 10) underwent unilateral photothrombotic lesion of the motor cortex of the forelimb and hind limb areas. Locomotion was video recorded before the insult and at postischemic days 7 and 28. Analysis of walking was performed frame-by-frame. Walking along the rung ladder revealed different results that were dependent on ladder inclination. Horizontal walking was found to discriminate lesion-related motor deficits in forelimb, whereas downward walking demonstrates hind limb use most sensitively. A more frequent use of the impaired forelimb that possibly supported poststroke motor learning in rats was shown. The present study provides a novel system for a detailed analysis of the complete walking sequence and will help to provide a better understanding of how rats deal with motor impairments. PMID:23577278

  3. Topic Order in Introductory Physics and its Impact on the STEM Curricular Ladder

    Directory of Open Access Journals (Sweden)

    Teresa L Larkin


    Full Text Available Introductory physics courses are an important rung on the curricular ladder in STEM. These courses help to strengthen students critical thinking and problem solving skills while simultaneously introducing them to many topics they will explore in more detail in later courses in physics and engineering. For these reasons, introductory physics is a required element on the curricular ladder. Most often, introductory physics is offered as a two-semester sequence with basic mechanics being taught in the first semester and electricity and magnetism in the second. In fact, this curricular sequence has not been altered in decades. Is there a reason for this? There are many other enduring questions that arise pertaining to these foundation courses in physics. These questions include: Does taking the introductory course sequence “out of order” have an impact on student learning in physics? What topics should be taught? When should these topics be taught? What topics could be left out? The list of questions is essentially endless. This paper will address some of these questions in part, through a brief discussion on student learning in a second-semester algebra-based physics course. Connections will also be made to the broader curricular ladder in STEM. To this end, an illustration that makes connections to an engineering statics course will be presented. This discussion will conclude by presenting some broader implications for the larger STEM communities.

  4. Cavity-induced artificial gauge field in a Bose-Hubbard ladder (United States)

    Halati, Catalin-Mihai; Sheikhan, Ameneh; Kollath, Corinna


    We consider theoretically ultracold interacting bosonic atoms confined to quasi-one-dimensional ladder structures formed by optical lattices and coupled to the field of an optical cavity. The atoms can collect a spatial phase imprint during a cavity-assisted tunneling along a rung via Raman transitions employing a cavity mode and a transverse running wave pump beam. By adiabatic elimination of the cavity field we obtain an effective Hamiltonian for the bosonic atoms, with a self-consistency condition. Using the numerical density-matrix renormalization-group method, we obtain a rich steady-state diagram of self-organized steady states. Transitions between superfluid to Mott-insulating states occur, on top of which we can have Meissner, vortex liquid, and vortex lattice phases. Also a state that explicitly breaks the symmetry between the two legs of the ladder, namely, the biased-ladder phase, is dynamically stabilized. We investigate the influence that a trapping potential has on the stability of the self-organized phases.

  5. Effect of Ladder Drill Exercise on Speed, Surrounding, and Power Leg Muscle

    Directory of Open Access Journals (Sweden)

    Ketut Chandra Adinata Kusuma


    Full Text Available This study aimed at finding the effect of ladder drill training upon: (1 run speed, (2 agility, and (2 power of leg muscle. This study is an experimental research. This study utilized one group pre test-post test design. There were total people as the subject of this research. Data collection technique used 30-meter sprint test to measure run speed, Illinois agility test to measure agility, and vertical jump test to measure power of leg muscle. Data analysis technique which was used for normality test, homogeneity test/F-test, and T-test with significant level 5% by using SPSS 16.0.0. Based on the finding, there was effect of ladder drill training upon run speed with sig value=0.007, agility and power of leg muscle with sig value=0.000. Based on the data analysis, it could be concluded that there was significant effect of ladder drill training upon run speed, agility and power of leg muscle.

  6. Haptic Discrimination of Distance (United States)

    van Beek, Femke E.; Bergmann Tiest, Wouter M.; Kappers, Astrid M. L.


    While quite some research has focussed on the accuracy of haptic perception of distance, information on the precision of haptic perception of distance is still scarce, particularly regarding distances perceived by making arm movements. In this study, eight conditions were measured to answer four main questions, which are: what is the influence of reference distance, movement axis, perceptual mode (active or passive) and stimulus type on the precision of this kind of distance perception? A discrimination experiment was performed with twelve participants. The participants were presented with two distances, using either a haptic device or a real stimulus. Participants compared the distances by moving their hand from a start to an end position. They were then asked to judge which of the distances was the longer, from which the discrimination threshold was determined for each participant and condition. The precision was influenced by reference distance. No effect of movement axis was found. The precision was higher for active than for passive movements and it was a bit lower for real stimuli than for rendered stimuli, but it was not affected by adding cutaneous information. Overall, the Weber fraction for the active perception of a distance of 25 or 35 cm was about 11% for all cardinal axes. The recorded position data suggest that participants, in order to be able to judge which distance was the longer, tried to produce similar speed profiles in both movements. This knowledge could be useful in the design of haptic devices. PMID:25116638

  7. Haptic discrimination of distance.

    Directory of Open Access Journals (Sweden)

    Femke E van Beek

    Full Text Available While quite some research has focussed on the accuracy of haptic perception of distance, information on the precision of haptic perception of distance is still scarce, particularly regarding distances perceived by making arm movements. In this study, eight conditions were measured to answer four main questions, which are: what is the influence of reference distance, movement axis, perceptual mode (active or passive and stimulus type on the precision of this kind of distance perception? A discrimination experiment was performed with twelve participants. The participants were presented with two distances, using either a haptic device or a real stimulus. Participants compared the distances by moving their hand from a start to an end position. They were then asked to judge which of the distances was the longer, from which the discrimination threshold was determined for each participant and condition. The precision was influenced by reference distance. No effect of movement axis was found. The precision was higher for active than for passive movements and it was a bit lower for real stimuli than for rendered stimuli, but it was not affected by adding cutaneous information. Overall, the Weber fraction for the active perception of a distance of 25 or 35 cm was about 11% for all cardinal axes. The recorded position data suggest that participants, in order to be able to judge which distance was the longer, tried to produce similar speed profiles in both movements. This knowledge could be useful in the design of haptic devices.

  8. Tourists consuming distance

    DEFF Research Database (Denmark)

    Larsen, Gunvor Riber

    contribute to an understanding of how it is possible to change tourism travel behaviour towards becoming more sustainable. How tourists 'consume distance' is discussed, from the practical level of actually driving the car or sitting in the air plane, to the symbolic consumption of distance that occurs when......The environmental impact of tourism mobility is linked to the distances travelled in order to reach a holiday destination, and with tourists travelling more and further than previously, an understanding of how the tourists view the distance they travel across becomes relevant. Based on interviews...... travelling on holiday becomes part of a lifestyle and a social positioning game. Further, different types of tourist distance consumers are identified, ranging from the reluctant to the deliberate and nonchalant distance consumers, who display very differing attitudes towards the distance they all travel...

  9. Interface Simulation Distances

    Directory of Open Access Journals (Sweden)

    Pavol Černý


    Full Text Available The classical (boolean notion of refinement for behavioral interfaces of system components is the alternating refinement preorder. In this paper, we define a distance for interfaces, called interface simulation distance. It makes the alternating refinement preorder quantitative by, intuitively, tolerating errors (while counting them in the alternating simulation game. We show that the interface simulation distance satisfies the triangle inequality, that the distance between two interfaces does not increase under parallel composition with a third interface, and that the distance between two interfaces can be bounded from above and below by distances between abstractions of the two interfaces. We illustrate the framework, and the properties of the distances under composition of interfaces, with two case studies.

  10. Software Verification and Validation Test Report for the HEPA filter Differential Pressure Fan Interlock System

    International Nuclear Information System (INIS)

    ERMI, A.M.


    The HEPA Filter Differential Pressure Fan Interlock System PLC ladder logic software was tested using a Software Verification and Validation (VandV) Test Plan as required by the ''Computer Software Quality Assurance Requirements''. The purpose of his document is to report on the results of the software qualification

  11. Analysis and demonstration of single-passband response and tuning characteristics in a chirped ladder interferometric filter for a widely tunable laser diode. (United States)

    Jeong, Seok-Hwan; Matsuo, Shinji; Yoshikuni, Yuzo; Segawa, Toru; Ohiso, Yoshitaka; Suzuki, Hiroyuki


    We have designed and demonstrated a chirped ladder-type tunable filter and discussed its potential application for a tunable diode laser. A ladder interferometric filter normally has a periodic passband, which makes it impossible to stabilize laser oscillation frequency. To overcome this drawback, we have designed, fabricated, and characterized a novel chirped tunable ladder filter. We have successfully demonstrated a single-passband response in the fabricated device. Furthermore, a tuning operation of more than 30 nm was achieved by introducing a current injection structure and optimizing electrode lengths at each single-stage ladder interferometer.

  12. A one-dimensional ladder-like coordination polymer: poly[[hexaaquabis(μ-5-nitrobenzene-1,3-dicarboxylato-κ3O,O′,O′′(μ-oxalato-κ4O,O′:O′′,O′′′diyttrium(III] trihydrate

    Directory of Open Access Journals (Sweden)

    Zhong Fu


    Full Text Available In the crystal structure of the title one-dimensional coordination polymer, [Y2(C8H3NO62(C2O4(H2O6]·3H2O, each YIII ion is bridged to its neighbours by two 5-nitrobenzene-1,3-dicarboxylate (nbdc dianions and one oxalate dianion (located on an inversion centre to form a ladder-like polymeric structure. The two carboxylate groups of nbdc assume different modes of coordination, one is chelating whereas the other is monodentate. Three water molecules coordinate to the YIII ion to complete an eight-coordinate distorted dodecahedral geometry. The ladder-like polymers are assembled together by hydrogen bonding and π–π stacking [centrio–centriod distance = 3.819 (9 Å] in the crystal structure.

  13. New insights into the origin of ladder dikes: Implications for punctuated growth and crystal accumulation in the Cathedral Peak granodiorite (United States)

    Wiebe, R. A.; Jellinek, A. M.; Hodge, K. F.


    Ladder dikes are steep tabular bodies, typically a meter or less thick, composed of moderately dipping, concave upward, alternating dark (i.e. schlieren) and light bands oriented roughly perpendicular to the ladder dike margins. These structures occur widely but sparsely in granitic rocks and are found prominently in the Cathedral Peak granodiorite (CPG) of the Tuolumne Intrusive suite. Previous studies have interpreted that ladder dikes form as a result of processes including the downward flow of crystal mush in cracks within strong crystal mush or by upward flow in steep tubes that migrate within a strong crystal mush. Our new observations indicate that ladder dikes formed by downward flow of crystal mush in troughs or valleys, in a manner potentially comparable to trough bands in mafic layered intrusions. Extensions of the schlieren outward and upward away from the ladder dike margins into the host granite demonstrate that the host granite was deposited as mounds on both sides at the same time as the ladder dikes. Ladder dikes, therefore, record lateral flows of crystal mush on a magma chamber floor. Vertical exposures suggest these flows are on the order of ten meters thick. Some steep exposures on granite domes indicate multiple ladder dikes (and flows) over a stratigraphic height of 80-100 m. Later (stratigraphically higher) flows commonly deform and erode the top of an earlier flow, and granitic material rich in K-feldspar megacrysts has locally engulfed large blocks of ladder dikes, demonstrating that the megacrysts were also transported in flows. Flows in the CPG are directed away from the center of the pluton toward the western and eastern margins and apparently spread along a strong crystal mush floor and into a rheologically complex CPG magma. Whereas established dynamical models for spreading (single phase) gravity currents with simple and complex rheologies explain the elongate geometry, spacing and orientation of the tabular bodies, the origin and

  14. Numerical distance protection

    CERN Document Server

    Ziegler, Gerhard


    Distance protection provides the basis for network protection in transmission systems and meshed distribution systems. This book covers the fundamentals of distance protection and the special features of numerical technology. The emphasis is placed on the application of numerical distance relays in distribution and transmission systems.This book is aimed at students and engineers who wish to familiarise themselves with the subject of power system protection, as well as the experienced user, entering the area of numerical distance protection. Furthermore it serves as a reference guide for s

  15. Clustering of local group distances: publication bias or correlated measurements? I. The large Magellanic cloud

    Energy Technology Data Exchange (ETDEWEB)

    De Grijs, Richard [Kavli Institute for Astronomy and Astrophysics, Peking University, Yi He Yuan Lu 5, Hai Dian District, Beijing 100871 (China); Wicker, James E. [National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing 100012 (China); Bono, Giuseppe [Dipartimento di Fisica, Università di Roma Tor Vergata, via Della Ricerca Scientifica 1, I-00133 Roma (Italy)


    The distance to the Large Magellanic Cloud (LMC) represents a key local rung of the extragalactic distance ladder yet the galaxy's distance modulus has long been an issue of contention, in particular in view of claims that most newly determined distance moduli cluster tightly—and with a small spread—around the 'canonical' distance modulus, (m – M){sub 0} = 18.50 mag. We compiled 233 separate LMC distance determinations published between 1990 and 2013. Our analysis of the individual distance moduli, as well as of their two-year means and standard deviations resulting from this largest data set of LMC distance moduli available to date, focuses specifically on Cepheid and RR Lyrae variable-star tracer populations, as well as on distance estimates based on features in the observational Hertzsprung-Russell diagram. We conclude that strong publication bias is unlikely to have been the main driver of the majority of published LMC distance moduli. However, for a given distance tracer, the body of publications leading to the tightly clustered distances is based on highly non-independent tracer samples and analysis methods, hence leading to significant correlations among the LMC distances reported in subsequent articles. Based on a careful, weighted combination, in a statistical sense, of the main stellar population tracers, we recommend that a slightly adjusted canonical distance modulus of (m – M){sub 0} = 18.49 ± 0.09 mag be used for all practical purposes that require a general distance scale without the need for accuracies of better than a few percent.

  16. Fish ladder of Lajeado Dam: migrations on one-way routes?

    Directory of Open Access Journals (Sweden)

    Angelo Antônio Agostinho

    Full Text Available Fish ladders are generally conceived to reestablish connectivity among critical habitats for migratory species, thus mitigating the impacts of the blockage of migration routes by dams. If this management tool is to be meaningful for conserving fish species, it must provide a fully permeable connection and assure both upward and downward movements. However, because reservoirs have very different hydrodynamics than the original river, it is expected that, at least in the inner area, they may constitute an additional barrier to this movement, especially for descending fish. Thus, the present study sought to determine if migratory fish and their offspring disperse downstream from the dam after ascending a ladder and spawning in the upper reaches of a basin. To achieve this purpose, we evaluated the limitation imposed by lentic areas to the descent of eggs, larvae and adults of migratory species; we also determined the abundance and composition of larvae present in the plankton near the dam, and compared the intensity of the upward and downward movements of adult fish. Samples of ichthyoplankton were taken upriver, inside the reservoir, in the river downstream from the dam, and in the forebay of the Lajeado Dam on the Tocantins River (Luis Eduardo Magalhães Hydroelectric Plant, from October, 1999 through September, 2004. The densities of fish ascending and descending the ladder were determined experimentally on eight occasions, from June, 2004 to March, 2005. Due to difficulties in identifying the true fish origin (up or down in the environments connected by the fish passage system, the evaluation of the distribution of migratory fish in reservoirs was based on the landings of the commercial fishery conducted along the Itaipu Reservoir during the four years preceding (2001 through 2003 the construction of the lateral channel (fish-passage mechanism. Fish eggs and larvae drifting down the Tocantins River did not appear in samples taken in the lower

  17. [Ladder step strategy for surgical repair of congenital concealed penis in children]. (United States)

    Wang, Fu-Ran; Zhong, Hong-Ji; Chen, Yi; Zhao, Jun-Feng; Li, Yan


    To assess the feasibility of the ladder step strategy in surgical repair of congenital concealed penis in children. This study included 52 children with congenital concealed penis treated in the past two years by surgical repair using the ladder step strategy, which consists of five main steps: cutting the narrow ring of the foreskin, degloving the penile skin, fixing the penile skin at the base, covering the penile shaft, and reshaping the prepuce. The perioperative data of the patients were prospectively collected and statistically described. Of the 52 patients, 20 needed remodeling of the frenulum and 27 received longitudinal incision in the penoscrotal junction to expose and deglove the penile shaft. The advanced scrotal flap technique was applied in 8 children to cover the penile shaft without tension, the pedicled foreskin flap technique employed in 11 to repair the penile skin defect, and excision of the webbed skin of the ventral penis performed in another 44 to remodel the penoscrotal angle. The operation time, blood loss, and postoperative hospital stay were 40-100 minutes, 5-30 ml, and 3-6 days, respectively. Wound bleeding and infection occurred in 1 and 5 cases, respectively. Follow-up examinations at 3 and 6 months after surgery showed that all the children had a satisfactory penile appearance except for some minor complications (2 cases of penile retraction, 2 cases of redundant ventral skin, and 1 case of iatrogenic penile curvature). The ladder step strategy for surgical repair of congenital concealed penis in children is a simple procedure with minor injury and satisfactory appearance of the penis.

  18. Frustrated quantum magnetism in the Kondo lattice on the zigzag ladder (United States)

    Peschke, Matthias; Rausch, Roman; Potthoff, Michael


    The interplay between the Kondo effect, indirect magnetic interaction, and geometrical frustration is studied in the Kondo lattice on the one-dimensional zigzag ladder. Using the density-matrix renormalization group, the ground-state and various short- and long-range spin- and density-correlation functions are calculated for the model at half filling as a function of the antiferromagnetic Kondo interaction down to J =0.3 t , where t is the nearest-neighbor hopping on the zigzag ladder. Geometrical frustration is shown to lead to at least two critical points: Starting from the strong-J limit, where almost local Kondo screening dominates and where the system is a nonmagnetic Kondo insulator, antiferromagnetic correlations between nearest-neighbor and next-nearest-neighbor local spins become stronger and stronger, until at Jcdim≈0.89 t frustration is alleviated by a spontaneous breaking of translational symmetry and a corresponding transition to a dimerized state. This is characterized by antiferromagnetic correlations along the legs and by alternating antiferro- and ferromagnetic correlations on the rungs of the ladder. A mechanism of partial Kondo screening that has been suggested for the Kondo lattice on the two-dimensional triangular lattice is not realized in the one-dimensional case. Furthermore, within the symmetry-broken dimerized state, there is a magnetic transition to a 90∘ quantum spin spiral with quasi-long-range order at Jcmag≈0.84 t . The quantum-critical point is characterized by a closure of the spin gap (with decreasing J ) and a divergence of the spin-correlation length and of the spin-structure factor S (q ) at wave vector q =π /2 . This is opposed to the model on the one-dimensional bipartite chain, which is known to have a finite spin gap for all J >0 at half filling.

  19. The Pan-STARRS 1 Photometric Reference Ladder, Release 12.01 (United States)

    Magnier, E. A.; Schlafly, E.; Finkbeiner, D.; Juric, M.; Tonry, J. L.; Burgett, W. S.; Chambers, K. C.; Flewelling, H. A.; Kaiser, N.; Kudritzki, R.-P.; Morgan, J. S.; Price, P. A.; Sweeney, W. E.; Stubbs, C. W.


    As of 2012 January 21, the Pan-STARRS 1 3π Survey has observed the 3/4 of the sky visible from Hawaii with a minimum of 2 and mean of 7.6 observations in five filters, g P1, r P1, i P1, z P1, y P1. Now at the end of the second year of the mission, we are in a position to make an initial public release of a portion of this unprecedented data set. This article describes the PS1 Photometric Ladder, Release 12.01. This is the first of a series of data releases to be generated as the survey coverage increases and the data analysis improves. The Photometric Ladder has rungs every hour in right ascension and at four intervals in declination. We will release updates with increased area coverage (more rungs) from the latest data set until the PS1 survey and the final re-reduction are completed. The currently released catalog presents photometry of ~1000 objects per square degree in the rungs of the ladder. Saturation occurs at g P1, r P1, i P1 ~ 13.5; z P1 ~ 13.0; and y P1 ~ 12.0. Photometry is provided for stars down to g P1, r P1, i P1 ~ 19.1 in the AB system. This data release depends on the rigid "Ubercal" photometric calibration using only the photometric nights, with systematic uncertainties of (8.0, 7.0, 9.0, 10.7, 12.4) mmag in (g P1, r P1, i P1, z P1, y P1). Areas covered only with lower quality nights are also included, and have been tied to the Ubercal solution via relative photometry; photometric accuracy of the non-photometric regions is lower and should be used with caution.


    Directory of Open Access Journals (Sweden)

    Raquel Engelman


    Full Text Available A pesquisa visou identificar valores dos empreendedores sociais com base na técnica Laddering, bem como a relação com o marketing social. Os principais atributos se referem ao engajamento social, ser proprietário de negócio e ter poder de decisão sobre sua própria vida. As principais consequências são autonomia, reconhecimento e transformação da sociedade. Entre os principais valores estão satisfação pessoal, bem-estar social e felicidade. As oportunidades estão relacionadas ao envolvimento prévio com a causa social, área de formação do empreendedor e suas redes de relacionamentos. As principais formas utilizadas para a comunicação e mobilização das pessoas são as mídias sociais. O estudo se mostrou importante para contribuir com maior conhecimento sobre as características peculiares do empreendedor social. Sobre a técnica Laddering, apesar de comumente ser utilizada para compreender relações de consumo, também se mostrou extremamente útil para compreender os valores mais íntimos que levam as pessoas a empreender socialmente, ao invés de empreender em negócios tradicionais ou se tornarem voluntários em uma organização social já constituída. Palavras-chave: Marketing Social. Empreendedorismo social. Laddering.

  1. Phase transitions and magnetization of the mixed-spin Ising–Heisenberg double sawtooth frustrated ladder (United States)

    Arian Zad, Hamid; Ananikian, Nerses


    The mixed spin-(1,1/2) Ising–Heisenberg double sawtooth ladder containing a mixture of both spin-1 and spin-1/2 nodal atoms, and the spin-1/2 interstitial dimers are approximately solved by the transfer-matrix method. Here, we study in detail the ground-state phase diagrams, also influences of the bilinear exchange coupling on the rungs and cyclic four-spin exchange interaction in square plaquette of each block on the magnetization and magnetic susceptibility of the suggested ladder at low temperature. Such a double sawtooth ladder may be found in a Shastry-Sutherland lattice-type. In spite of the spin ordering of odd and even blocks being different from each other, due to the commutation relation between all different block Hamiltonians, phase diagrams, magnetization behavior and thermodynamic properties of the model are the same for odd and even blocks. We show that at low temperature, both exchange couplings can change the quality and quantity of the magnetization plateaus versus the magnetic field changes. Specially, we find a new magnetization plateau M/Ms= 5/6 for this model. Besides, we examine the magnetic susceptibility and specific heat of the model in detail. It is proven that behaviors of the magnetization and the magnetic susceptibility coincide at low temperature. The specific heat displays diverse temperature dependencies, which include a Schottky-type peak at a special temperature interval. We observe that with increase of the bilinear exchange coupling on the rungs, second peak temperature dependence grows.

  2. Measurement of the Rise-Time in a Single Sided Ladder Detector

    International Nuclear Information System (INIS)

    Gerber, C.E.


    In this note we report on the measurement of the preamplifier output rise time for a SVXII chip mounted on a D0 single sided ladder. The measurements were performed on the ladder 001-883-L, using the laser test stand of Lab D. The rise time was measured for different values of the response (or bandwidth) of the preamplifier. As a bigger bandwidth results in longer rise times and therefore in less noise, the largest possible bandwidth consistent with the time between bunch crossings should be chosen to operate the detectors. The rise time is defined as the time elapsed between 10% and 90% of the charge is collected. It is also interesting to measure the time for full charge collection and the percentage of charge collected in 132 ns and 396 ns. The results are shown in table 1, for bandwidths between 2 and 63 (binary numbers). The uncertainty on the time measurement is considered to be ∼ 10 ns. Figure 1 schematically defines the four quantities measured: rise time, time of full charge collection, and percentage of charge collected in 132 ns and 396 ns. Figures 2 to 8 are the actual measurements for bandwidths of 2, 4, 8, 12, 24, 32 and 63. Figure 9 is a second measurement for BW=24, used as a consistency check of the system and the time measurement performed on the plots. The data indicate that the single sided ladders can be operated at BW=63 for 396 ns and BW=12 for 132 ns, achieving full charge collection. This will result in smaller noise than originally anticipated.

  3. Bifurcation in Ground-state Fidelity and Quantum Criticality in Two-leg Potts Ladder

    Directory of Open Access Journals (Sweden)

    Sheng-Hao LI


    Full Text Available We have investigated an intriguing connection between bifurcations, reduced fidelity per lattice site, local order parameter, universal order parameter, entropy and quantum phase transitions in the ground state for quantum three-state Potts model with two coupled infinite-size ladder system, in the context of the tensor network algorithm. The tensor network algorithm produces degenerate symmetry-breaking ground-state wave functions arising from the Z3 symmetry breaking, each of results from a randomly chosen initial state. We expect that our approach might provide further insights into critical phenomena in quantum many-body infinite lattice systems in condensed matter physics.

  4. Topological insulation in a ladder model with particle-hole and reflection symmetries. (United States)

    Hetényi, B; Yahyavi, M


    A two-legged ladder model, one dimensional, exhibiting the parity anomaly is constructed. The model belongs to the C and CI symmetry classes, depending on the parameters, but, due to reflection, it exhibits topological insulation. The model consists of two superimposed Creutz models with onsite potentials. The topological invariants of each Creutz model sum to give the mirror winding number, with winding numbers which are nonzero individually but equal and opposite in the topological phase, and both zero in the trivial phase. We demonstrate the presence of edge states and quantized Hall response in the topological region. Our model exhibits two distinct topological regions, distinguished by the different types of reflection symmetries.

  5. Means-end chains and laddering: An inventory of problems and an agenda for research

    DEFF Research Database (Denmark)

    Grunert, Klaus G.; Beckmann, Suzanne C.; Sørensen, Elin


    and unconscious (or, at least, semiconscious) factors. It is intuitively appealing to the practitioner but has, likewise, attracted academic research. Increased acceptance and use of a new approach inevitably leads to the detection of unresolved issues and problems. Many of these unresolved issues are related...... to the collection and analysis of laddering data. However, many of these also point at problems of a more theoretical nature. In this chapter presented are some of the issues regarded as unresolved and suggested research that could help in solving these problems. The mayor part of this chapter deals...

  6. Large area VHF plasma production using a ladder-shaped electrode

    International Nuclear Information System (INIS)

    Mashima, H.; Yamakoshi, H.; Kawamura, K.; Takeuchi, Y.; Noda, M.; Yonekura, Y.; Takatsuka, H.; Uchino, S.; Kawai, Y.


    VHF excited plasma is produced with a ladder-shaped electrode and the plasma parameters are measured with a heated Langmuir probe. When the discharge frequency (∼ 100 MHz) of the RF power source is increased, the plasma density increases while the electron temperature decreases. Plasma uniformity less than 15% over 1.2 m x 1.5 m is realized by employing the phase modulation method, that is, the pattern of the standing wave on the electrode can be controlled by changing the phase of the RF power

  7. High-energy, large-momentum-transfer processes: Ladder diagrams in φ3 theory. Pt. 2

    International Nuclear Information System (INIS)

    Osland, P.; Wu, T.T.; Harvard Univ., Cambridge, MA


    The scattering amplitude for the four-rung ladder diagram in φ 3 theory is evaluated at high energies and for large momentum transfers. The result takes the form of s -1 vertical stroketvertical stroke -3 multiplied by a homogeneous sixth-order polynomial in ln s and 1nvertical stroketvertical stroke. The novel and unexpected feature is that this polynomial is different depending on whether 1n vertical stroketvertical stroke is larger or less than 1/2 1n s. Thus the asymptotic formula is not analytic at 1n vertical stroketvertical stroke=1/2 1n s, although the first five derivatives are continuous. (orig.)

  8. Phase dynamics of a Josephson junction ladder driven by modulated currents

    International Nuclear Information System (INIS)

    Kawaguchi, T.


    Phase dynamics of disordered Josephson junction ladders (JJLs) driven by external currents which are spatially and temporally modulated is studied using a numerical simulation based on a random field XY model. This model is considered theoretically as an effective model of JJLs with structural disorder in a magnetic field. The spatiotemporal modulation of external currents causes peculiar dynamical effects of phases in the system under certain conditions, such as the directed motion of phases and the mode-locking in the absence of dc currents. We clarify the details of effects of the spatiotemporal modulation on the phase dynamics.

  9. Magnetic dimerization in the frustrated spin ladder Li2Cu2O (SO4)2 (United States)

    Vaccarelli, O.; Rousse, G.; Saúl, A.; Radtke, G.


    The magnetic properties of Li2Cu2O (SO4)2 are investigated in the framework of density functional theory. In its high-temperature tetragonal structure, this compound appears as a rare material realization of a frustrated spin-1/2 two-leg ladder, where magnetic frustration arises from competing nearest and next-nearest interactions along the legs. Through a large magnetoelastic coupling, the triclinic distortion occurring around 125 K is shown to induce the formation of a staggered dimer structure, lifting most of the magnetic frustration.

  10. Distance Education in Turkey

    Directory of Open Access Journals (Sweden)

    Dr. Nursel Selver RUZGAR,


    Full Text Available Distance Education in Turkey Assistant Professor Dr. Nursel Selver RUZGAR Technical Education Faculty Marmara University, TURKEY ABSTRACT 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 aspect of the view. Then, in order to create the tendencies and thoughts of graduates of Higher Education Institutions and Distance Education Institutions about being competitors in job markets, sufficiency of education level, advantages for education system, continuing education in different Institutions, a face-to-face survey was applied to 1284 graduates, 958 from Higher Education Institutions and 326 from Distance Education Institutions. The results were evaluated and discussed. In the last part of this work, suggestions to become widespread and improve the distance education in the country were made.

  11. Duty and Distance

    NARCIS (Netherlands)

    C. Binder (C.); C. Heilmann (Conrad)


    markdownabstractEver since the publication of Peter Singer’s article ‘‘Famine, Affluence, and Morality’’ has the question of whether the (geographical) distance to people in need affects our moral duties towards them been a hotly debated issue. Does geographical distance affect our moral

  12. Information distance in multiples

    NARCIS (Netherlands)

    P.M.B. Vitányi (Paul)


    htmlabstractInformation distance is a parameter-free similarity measure based on compression, used in pattern recognition, data mining, phylogeny, clustering, and classification. The notion of information distance is extended from pairs to multiples (finite lists). We study maximal overlap,

  13. Normalized information distance

    NARCIS (Netherlands)

    Vitányi, P.M.B.; Balbach, F.J.; Cilibrasi, R.L.; Li, M.; Emmert-Streib, F.; Dehmer, M.


    The normalized information distance is a universal distance measure for objects of all kinds. It is based on Kolmogorov complexity and thus uncomputable, but there are ways to utilize it. First, compression algorithms can be used to approximate the Kolmogorov complexity if the objects have a string

  14. Distance between Behaviors and Rational Representations

    NARCIS (Netherlands)

    Trentelman, H.L.; Gottimukkala, S.V.


    In this paper we study notions of distance between behaviors of linear differential systems. We introduce four metrics on the space of all controllable behaviors which generalize existing metrics on the space of input-output systems represented by transfer matrices. Three of these are defined in

  15. Isolation-by-distance in landscapes: considerations for landscape genetics (United States)

    van Strien, M J; Holderegger, R; Van Heck, H J


    In landscape genetics, isolation-by-distance (IBD) is regarded as a baseline pattern that is obtained without additional effects of landscape elements on gene flow. However, the configuration of suitable habitat patches determines deme topology, which in turn should affect rates of gene flow. IBD patterns can be characterized either by monotonically increasing pairwise genetic differentiation (for example, FST) with increasing interdeme geographic distance (case-I pattern) or by monotonically increasing pairwise genetic differentiation up to a certain geographical distance beyond which no correlation is detectable anymore (case-IV pattern). We investigated if landscape configuration influenced the rate at which a case-IV pattern changed to a case-I pattern. We also determined at what interdeme distance the highest correlation was measured between genetic differentiation and geographic distance and whether this distance corresponded to the maximum migration distance. We set up a population genetic simulation study and assessed the development of IBD patterns for several habitat configurations and maximum migration distances. We show that the rate and likelihood of the transition of case-IV to case-I FST–distance relationships was strongly influenced by habitat configuration and maximum migration distance. We also found that the maximum correlation between genetic differentiation and geographic distance was not related to the maximum migration distance and was measured across all deme pairs in a case-I pattern and, for a case-IV pattern, at the distance where the FST–distance curve flattens out. We argue that in landscape genetics, separate analyses should be performed to either assess IBD or the landscape effects on gene flow. PMID:25052412

  16. Improving energy and carbon management in construction and civil engineering companies—evaluating the impacts of the CO2 Performance Ladder

    NARCIS (Netherlands)

    Rietbergen, Martijn G.; Opstelten, Ivo J.; Blok, Kornelis

    In the Netherlands, the CO2 Performance Ladder has been introduced as an energy management programme to facilitate continuous energy efficiency and carbon performance improvement in non-industrial sectors. This paper addresses the question: ‘What is the impact of the CO2 Performance Ladder on

  17. Field-controlled magnetic order in the quantum spin-ladder system (Hpip)2CuBr4

    DEFF Research Database (Denmark)

    Thielemann, B.; Rüegg, C.; Kiefer, K.


    Neutron diffraction is used to investigate the field-induced, antiferromagnetically ordered state in the two-leg spin-ladder material (Hpip)(2)CuBr4. This "classical" phase, a consequence of weak interladder coupling, is nevertheless highly unconventional: its properties are influenced strongly b...... the quantum fluctuation corrections to the mean-field interaction.......Neutron diffraction is used to investigate the field-induced, antiferromagnetically ordered state in the two-leg spin-ladder material (Hpip)(2)CuBr4. This "classical" phase, a consequence of weak interladder coupling, is nevertheless highly unconventional: its properties are influenced strongly...

  18. Two-leg ladder systems with dipole–dipole Fermion interactions (United States)

    Mosadeq, Hamid; Asgari, Reza


    The ground-state phase diagram of a two-leg fermionic dipolar ladder with inter-site interactions is studied using density matrix renormalization group (DMRG) techniques. We use a state-of-the-art implementation of the DMRG algorithm and finite size scaling to simulate large system sizes with high accuracy. We also consider two different model systems and explore stable phases in half and quarter filling factors. We find that in the half filling, the charge and spin gaps emerge in a finite value of the dipole–dipole and on-site interactions. In the quarter filling case, s-wave superconducting state, charge density wave, homogenous insulating and phase separation phases occur depend on the interaction values. Moreover, in the dipole–dipole interaction, the D-Mott phase emerges when the hopping terms along the chain and rung are the same, whereas, this phase has been only proposed for the anisotropic Hubbard model. In the half filling case, on the other hand, there is either charge-density wave or charged Mott order phase depends on the orientation of the dipole moments of the particles with respect to the ladder geometry.

  19. Ground-state and spectral properties of an asymmetric Hubbard ladder (United States)

    Abdelwahab, Anas; Jeckelmann, Eric; Hohenadler, Martin


    We investigate a ladder system with two inequivalent legs, namely, a Hubbard chain and a one-dimensional electron gas. Analytical approximations, the density-matrix renormalization group method, and continuous-time quantum Monte Carlo simulations are used to determine ground-state properties, gaps, and spectral functions of this system at half-filling. Evidence for the existence of four different phases as a function of the Hubbard interaction and the rung hopping is presented. First, a Luttinger liquid exists at very weak interchain hopping. Second, a Kondo-Mott insulator with spin and charge gaps induced by an effective rung exchange coupling is found at moderate interchain hopping or strong Hubbard interaction. Third, a spin-gapped paramagnetic Mott insulator with incommensurate excitations and pairing of doped charges is observed at intermediate values of the rung hopping and the interaction. Fourth, the usual correlated band insulator is recovered for large rung hopping. We show that the wave numbers of the lowest single-particle excitations are different in each insulating phase. In particular, the three gapped phases exhibit markedly different spectral functions. We discuss the relevance of asymmetric two-leg ladder systems as models for atomic wires deposited on a substrate.

  20. Quark-gluon vertex dressing and meson masses beyond ladder-rainbow truncation

    International Nuclear Information System (INIS)

    Matevosyan, Hrayr H.; Thomas, Anthony W.; Tandy, Peter C.


    We include a generalized infinite class of quark-gluon vertex dressing diagrams in a study of how dynamics beyond the ladder-rainbow truncation influences the Bethe-Salpeter description of light-quark pseudoscalar and vector mesons. The diagrammatic specification of the vertex is mapped into a corresponding specification of the Bethe-Salpeter kernel, which preserves chiral symmetry. This study adopts the algebraic format afforded by the simple interaction kernel used in previous work on this topic. The new feature of the present work is that in every diagram summed for the vertex and the corresponding Bethe-Salpeter kernel, each quark-gluon vertex is required to be the self-consistent vertex solution. We also adopt from previous work the effective accounting for the role of the explicitly non-Abelian three-gluon coupling in a global manner through one parameter determined from recent lattice-QCD data for the vertex. Within the current model, the more consistent dressed vertex limits the ladder-rainbow truncation error for vector mesons to be never more than 10% as the current quark mass is varied from the u/d region to the b region

  1. Energy-efficient hydrogen separation by AB-type ladder-polymer molecular sieves

    KAUST Repository

    Ghanem, Bader


    The synthesis, microstructures, and exceptional gas transport properties of two new soluble ladder polymers, polymers of intrinsic microporosity (TPIM-1 and TPIM-2) containing triptycene moieties substituted with branched isopropyl and linear propyl chains at the 9,10-bridgeheads were reported. The precursor A-B monomers were modified with an o -difluoride functionality for enhanced activation for nucleophilic aromatic substitution. In a Schlenk tube, a mixture of the A-B monomer, 18-crown-6, anhydrous DMF and anhydrous potassium carbonate was stirred at 155 °C under nitrogen atmosphere for 20 min followed by the addition of toluene. The reaction was continued for another 45 min and more toluene was added. After another 45 min the reaction mixture was cooled to room temperature and poured into methanol. Slow evaporation of filtered, dilute 3-5 wt% chloroform solutions from a leveled glass plate yielded isotropic polymer films. Dry membranes were soaked in methanol for 24 h, air-dried, and then heated at 120°C for 24 h under high vacuum to remove any traces of residual solvent. TPIM-1 exhibits simultaneous boosts in permeability and selectivity, which highlights the significant potential of an isopropyl-substituted triptycene moiety as a contortion center for ladder PIMs.

  2. Optimization of Vibration Reduction Ability of Ladder Tracks by FEM Coupled with ACO

    Directory of Open Access Journals (Sweden)

    Hao Jin


    Full Text Available Ladder track, which has drawn increased attention in scientific communities, is an effective method for reducing vibrations from underground railways. In order to optimize the vibration reduction ability of ladder track, a new method, that is, the finite element method (FEM coupled with ant colony optimization (ACO, has been proposed in this paper. We describe how to build the FEM model verified by the vibration tests in the Track Vibration Abatement and Control Laboratory and how to couple the FEM with ACO. The density and elasticity modulus of the sleeper pad are optimized using this method. After optimization, the vibration acceleration level of the supporting platform in the 1–200 Hz range was reduced from 102.8 dB to 94.4 dB. The optimized density of the sleeper pad is 620 kg/m3, and the optimized elasticity modulus of the sleeper pad is 6.25 × 106 N/m2.

  3. Quantum dynamics of bosons in a two-ring ladder: Dynamical algebra, vortexlike excitations, and currents (United States)

    Richaud, Andrea; Penna, Vittorio


    We study the quantum dynamics of the Bose-Hubbard model on a ladder formed by two rings coupled by the tunneling effect. By implementing the Bogoliubov approximation scheme, we prove that, despite the presence of the inter-ring coupling term, the Hamiltonian decouples in many independent sub-Hamiltonians Ĥk associated with momentum-mode pairs ±k . Each sub-Hamiltonian Ĥk is then shown to be part of a specific dynamical algebra. The properties of the latter allow us to perform the diagonalization process, to find the energy spectrum and the conserved quantities of the model, and to derive the time evolution of important physical observables. We then apply this solution scheme to the simplest possible closed ladder, the double trimer. After observing that the excitations of the system are weakly populated vortices, we explore the corresponding dynamics by varying the initial conditions and the model parameters. Finally, we show that the inter-ring tunneling determines a spectral collapse when approaching the border of the dynamical-stability region.

  4. Electronic states of doped spin ladders (Sr,Ca)14Cu24O41

    International Nuclear Information System (INIS)

    Mizuno, Yoshiaki; Tohyama, Takami; Maekawa, Sadamichi.


    We examine the electronic states of Sr 14-x Ca x Cu 24 O 41 by the ionic and cluster model approach. It is found that self-doped holes are likely to stay on the chain at x = 0 and Ca substitution drives the holes to move to the ladder. This feature is caused by changes of the positions of (Sr,Ca) layers, which results in enhancement of the electrostatic potentials in the chain. The optical conductivity is calculated with application of the exact diagonalization method to small Cu-O clusters. It is shown that the excitations below 2 eV are governed by the ladder, giving rise to the spectral weight transfer from the charge-transfer excitation at around 2 eV to low energy Drude excitation, while the contribution from the chain mainly emerges in a higher energy region showing large spectral weight at around 3 eV. These findings provide a consistent explanation for the results of a recent experiment. (author)

  5. Magnetic precursor of the pressure-induced superconductivity in Fe-ladder compound (United States)

    Chi, Songxue; Uwatoko, Yoshiya; Cao, Huibo; Hirata, Yasuyuki; Hashizume, Kazuki; Aoyama, Takuya; Ohgushi, Kenya

    The pressure effects on the antiferromagentic orders in iron-based ladder compounds CsFe2Se3 and BaFe2S3 have been studied using neutron diffraction. With identical crystal structure and similar magnetic structures, the two compounds exhibit highly contrasting magnetic behaviors under moderate external pressures. In CsFe2Se3 the ladders are brought much closer to each other by pressure, but the stripe-type magnetic order shows no observable change. In contrast, the stripe order in BaFe2S3, undergoes a quantum phase transition where an abrupt increase of N e xel temperature by more than 50% occurs at about 1 GPa, accompanied by a jump in the ordered moment. With its spin structure unchanged, BaFe2S3 enters an enhanced magnetic phase that bears the characteristics of an orbital selective Mott phase, which is the true neighbor of superconductivity emerging at higher pressures. Research at Oak Ridge National Laboratorys HFIR was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy.This work was supported by JSPS KAKENHI Grant Number 16H04019.

  6. Learning Pullback HMM Distances. (United States)

    Cuzzolin, Fabio; Sapienza, Michael


    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.

  7. Long distance quantum teleportation (United States)

    Xia, Xiu-Xiu; Sun, Qi-Chao; Zhang, Qiang; Pan, Jian-Wei


    Quantum teleportation is a core protocol in quantum information science. Besides revealing the fascinating feature of quantum entanglement, quantum teleportation provides an ultimate way to distribute quantum state over extremely long distance, which is crucial for global quantum communication and future quantum networks. In this review, we focus on the long distance quantum teleportation experiments, especially those employing photonic qubits. From the viewpoint of real-world application, both the technical advantages and disadvantages of these experiments are discussed.

  8. Einstein at a distance

    Energy Technology Data Exchange (ETDEWEB)

    Lambourne, Robert [Department of Physics and Astronomy, Open University, Milton Keynes (United Kingdom)


    This paper examines the challenges and rewards that can arise when the teaching of Einsteinian physics has to be accomplished by means of distance education. The discussion is mainly based on experiences gathered over the past 35 years at the UK Open University, where special and general relativity, relativistic cosmology and other aspects of Einsteinian physics, have been taught at a variety of levels, and using a range of techniques, to students studying at a distance.

  9. Distance Metric Tracking (United States)


    estimation [13, 2], and manifold learning [19]. Such unsupervised methods do not have the benefit of human input on the distance metric, and overly be defined that is related to the task at hand. Many supervised and semi- supervised distance metric learning approaches have been developed [17... Unsupervised PCA seeks to identify a set of axes that best explain the variance contained in the data. LDA takes a supervised approach, minimiz- ing the intra

  10. Game theory of social distancing in response to an epidemic.

    Directory of Open Access Journals (Sweden)

    Timothy C Reluga


    Full Text Available Social distancing practices are changes in behavior that prevent disease transmission by reducing contact rates between susceptible individuals and infected individuals who may transmit the disease. Social distancing practices can reduce the severity of an epidemic, but the benefits of social distancing depend on the extent to which it is used by individuals. Individuals are sometimes reluctant to pay the costs inherent in social distancing, and this can limit its effectiveness as a control measure. This paper formulates a differential-game to identify how individuals would best use social distancing and related self-protective behaviors during an epidemic. The epidemic is described by a simple, well-mixed ordinary differential equation model. We use the differential game to study potential value of social distancing as a mitigation measure by calculating the equilibrium behaviors under a variety of cost-functions. Numerical methods are used to calculate the total costs of an epidemic under equilibrium behaviors as a function of the time to mass vaccination, following epidemic identification. The key parameters in the analysis are the basic reproduction number and the baseline efficiency of social distancing. The results show that social distancing is most beneficial to individuals for basic reproduction numbers around 2. In the absence of vaccination or other intervention measures, optimal social distancing never recovers more than 30% of the cost of infection. We also show how the window of opportunity for vaccine development lengthens as the efficiency of social distancing and detection improve.

  11. Knowing One's Lot in Life versus Climbing the Social Ladder: The Formation of Redistributive Preferences in Urban China (United States)

    Smyth, Russell; Mishra, Vinod; Qian, Xiaolei


    This paper examines, how individual preferences for redistribution in general and redistribution to improve access to education, improve social protection for the poor, reduce income inequality and reduce unemployment depend on beliefs about what determines one's lot in life and self-assessed prospects for climbing the social ladder in urban…

  12. A Study of Career Ladders and Manpower Development for Non-Management Personnel in the Food Service Industry. (United States)

    State Univ. of New York, Ithaca. School of Hotel Administration at Cornell Univ.

    Because of its failure to provide career ladders for non-management employees, the food service industry is facing increasingly severe manpower shortages and labor turnover. Unnecessary requirements bar entry workers from many jobs, and training opportunities leave much to be desired. This report identifies the problem areas and develops a model…

  13. Heat transport imaging in the spin-ladder compound Ca9La5Cu24O41

    NARCIS (Netherlands)

    Otter, M.; Krasnikov, V. V.; Fishman, D. A.; Pshenichnikov, M. S.; Saint-Martin, R.; Revcolevschi, A.; van Loosdrecht, P. H. M.

    All-optical heat transport imaging on the spin-ladder compound Ca9La5Cu24O41 is presented. A 'time-of-flight' principle is discussed along with its experimental veri. cation which can be used to measure the bulk thermal diffusion constant. The results of the thermal imaging experiments clearly

  14. Spin- (1)/(2) Heisenberg ladder: Variation of entanglement and fidelity measures close to quantum critical points (United States)

    Tribedi, Amit; Bose, Indrani


    We consider a two-chain, spin- (1)/(2) antiferromagnetic Heisenberg spin ladder in an external magnetic field H . The spin ladder is known to undergo second-order quantum phase transitions (QPTs) at two critical values Hc1 and Hc2 of the magnetic field. There are now known examples of strongly coupled (where the rung exchange interaction is much stronger than the nearest-neighbor intrachain exchange interaction) organic ladder compounds in which QPTs have been experimentally observed. In this paper, we investigate whether well-known bipartite entanglement meaures such as one-site von Neumann entropy, two-site von Neumann entropy, and concurrence develop special features close to the quantum critical points. As suggested by an earlier theorem, the first derivatives of the measures with respect to magnetic field are expected to diverge as H→Hc1 and H→Hc2 . Based on numerical diagonalization data and a mapping of the strongly coupled ladder Hamiltonian onto the XXZ chain Hamiltonian, for which several analytical results are known, we find that the derivatives of the entanglement measures diverge as H→Hc2 but remain finite as H→Hc1 . The reason for this discrepancy is analyzed. We further calculate two recently proposed quantum information theoretic measures, the reduced fidelity and reduced fidelity susceptibility, and show that these measures provide appropriate signatures of the QPTs occuring at the critical points H=Hc1 and H=Hc2 .

  15. Detection of apoptotic DNA ladder in pig leukocytes and its precision using LM - PCR (ligation mediated polymerase chain reaction)

    Czech Academy of Sciences Publication Activity Database

    Matalová, Eva; Španová, A.


    Roč. 71, č. 3 (2002), s. 163-168 ISSN 0001-7213 R&D Projects: GA ČR GA304/01/0850; GA AV ČR KSK6005114 Keywords : apoptosis * phagocytosis * DNA ladder Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 0.370, year: 2002


    Energy Technology Data Exchange (ETDEWEB)

    Magnier, E. A.; Tonry, J. L.; Burgett, W. S.; Chambers, K. C.; Flewelling, H. A.; Kaiser, N.; Kudritzki, R.-P.; Morgan, J. S.; Sweeney, W. E. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Schlafly, E.; Finkbeiner, D.; Juric, M.; Stubbs, C. W. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Price, P. A. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)


    As of 2012 January 21, the Pan-STARRS 1 3{pi} Survey has observed the 3/4 of the sky visible from Hawaii with a minimum of 2 and mean of 7.6 observations in five filters, g {sub P1}, r {sub P1}, i {sub P1}, z {sub P1}, y {sub P1}. Now at the end of the second year of the mission, we are in a position to make an initial public release of a portion of this unprecedented data set. This article describes the PS1 Photometric Ladder, Release 12.01. This is the first of a series of data releases to be generated as the survey coverage increases and the data analysis improves. The Photometric Ladder has rungs every hour in right ascension and at four intervals in declination. We will release updates with increased area coverage (more rungs) from the latest data set until the PS1 survey and the final re-reduction are completed. The currently released catalog presents photometry of {approx}1000 objects per square degree in the rungs of the ladder. Saturation occurs at g {sub P1}, r {sub P1}, i {sub P1} {approx} 13.5; z {sub P1} {approx} 13.0; and y {sub P1} {approx} 12.0. Photometry is provided for stars down to g {sub P1}, r {sub P1}, i {sub P1} {approx} 19.1 in the AB system. This data release depends on the rigid 'Ubercal' photometric calibration using only the photometric nights, with systematic uncertainties of (8.0, 7.0, 9.0, 10.7, 12.4) mmag in (g {sub P1}, r {sub P1}, i {sub P1}, z {sub P1}, y {sub P1}). Areas covered only with lower quality nights are also included, and have been tied to the Ubercal solution via relative photometry; photometric accuracy of the non-photometric regions is lower and should be used with caution.

  17. Topologically clean distance fields. (United States)

    Gyulassy, Attila; Duchaineau, Mark; Natarajan, Vijay; Pascucci, Valerio; Bringa, Eduardo; Higginbotham, Andrew; Hamann, Bernd


    Analysis of the results obtained from material simulations is important in the physical sciences. Our research was motivated by the need to investigate the properties of a simulated porous solid as it is hit by a projectile. This paper describes two techniques for the generation of distance fields containing a minimal number of topological features, and we use them to identify features of the material. We focus on distance fields defined on a volumetric domain considering the distance to a given surface embedded within the domain. Topological features of the field are characterized by its critical points. Our first method begins with a distance field that is computed using a standard approach, and simplifies this field using ideas from Morse theory. We present a procedure for identifying and extracting a feature set through analysis of the MS complex, and apply it to find the invariants in the clean distance field. Our second method proceeds by advancing a front, beginning at the surface, and locally controlling the creation of new critical points. We demonstrate the value of topologically clean distance fields for the analysis of filament structures in porous solids. Our methods produce a curved skeleton representation of the filaments that helps material scientists to perform a detailed qualitative and quantitative analysis of pores, and hence infer important material properties. Furthermore, we provide a set of criteria for finding the "difference" between two skeletal structures, and use this to examine how the structure of the porous solid changes over several timesteps in the simulation of the particle impact.

  18. Trichromatic π-Pulse for Ultrafast Total Inversion of a Four-Level Ladder System

    Directory of Open Access Journals (Sweden)

    Carles Serrat


    Full Text Available We present a numerical solution for complete population inversion in a four-level ladder system obtained by using a full π-pulse illumination scheme with resonant ultrashort phase-locked Gaussian laser pulses. We find that a set of pulse areas such as √3π , √2π , and √3π completely inverts the four-level system considering identical effective dipole coupling coefficients. The solution is consistent provided the involved electric fields are not too strong and it is amply accurate also in the case of diverse transition dipole moments. We study the effect of detuning and chirp of the laser pulses on the complete population inversion using the level structure of atomic sodium interacting with ps and fs pulses as an example. Our result opens the door for multiple applications such as efficient ultrashort pulse lasing in the UV or the engineering of quantum states for quantum computing.

  19. Towers and ladders: Infinite parameter symmetries in Kaluza-Klein theories

    International Nuclear Information System (INIS)

    Aulakh, C.S.


    We introduce a class of infinite dimensional algebras with a 'generalized loop structure' by considering the global symmetries of the four dimensional Lagrangian obtained by compactifying general relativity coupled to Yang-Mills in six dimensions down to M 4 xS 2 . The generalization to arbitrary dimensions is then obvious. We show by explicit construction that such algebras possess an infinite number of finite sub-algebras. Among which, for the six dimensional case, is so(1,3) realized on S 2 with vanishing Casimir invariants. This so(1,3) may be interpreted, in accord with a previous conjecture of Salam and Strathdee [Ann. Phys. 141, 316(1982)], as the 'ladder' symmetry for the Kaluza-Klein towers. (author)

  20. A renormalization approach to describe charge transport in quasiperiodic dangling backbone ladder (DBL)-DNA molecules

    Energy Technology Data Exchange (ETDEWEB)

    Sarmento, R.G. [Departamento de Fisica, Universidade Federal do Rio Grande do Norte, 59072-970 Natal, RN (Brazil); Fulco, U.L. [Departamento de Biofisica e Farmacologia, Universidade Federal do Rio Grande do Norte, 59072-970 Natal, RN (Brazil); Albuquerque, E.L., E-mail: [Departamento de Biofisica e Farmacologia, Universidade Federal do Rio Grande do Norte, 59072-970 Natal, RN (Brazil); Caetano, E.W.S. [Instituto Federal de Educacao, Ciencia e Tecnologia do Ceara, 60040-531 Fortaleza, CE (Brazil); Freire, V.N. [Departamento de Fisica, Universidade Federal do Ceara, 60455-760 Fortaleza, CE (Brazil)


    Highlights: → One-step renormalization approach to describe the DBL-DNA molecule. → Electronic tight-binding Hamiltonian model. → A quasiperiodic sequence to mimic the DNA nucleotides arrangement. → Electronic transmission spectra. → I-V characteristics. -- Abstract: We study the charge transport properties of a dangling backbone ladder (DBL)-DNA molecule focusing on a quasiperiodic arrangement of its constituent nucleotides forming a Rudin-Shapiro (RS) and Fibonacci (FB) Poly (CG) sequences, as well as a natural DNA sequence (Ch22) for the sake of comparison. Making use of a one-step renormalization process, the DBL-DNA molecule is modeled in terms of a one-dimensional tight-binding Hamiltonian to investigate its transmissivity and current-voltage (I-V) profiles. Beyond the semiconductor I-V characteristics, a striking similarity between the electronic transport properties of the RS quasiperiodic structure and the natural DNA sequence was found.

  1. Of towers and ladders: Infinite parameter symmetries in Kaluza-Klein theories

    International Nuclear Information System (INIS)

    Aulakh, C.S.


    We introduce a class of infinite dimensional algebras with a 'generalized loop structure' by considering the global symmetries of the four-dimensional lagrangian obtained by compactifying general relativity coupled to Yang-Mills in six-dimensions down to M 4 x S 2 . The generalization to arbitrary dimensions is then obvious. We show by explicit construction that such algebras possess an infinite number of finite sub-algebras among which, for the six-dimensional case, is so (1, 3), realized on S 2 with vanishing Casimir invariants. This so (1, 3) may be interpreted, in accordance with a previous conjecture of Salam and Strathdee, as the 'ladder' symmetry for the Kaluza-Klein towers. (orig.)

  2. Spectral properties of an extended Hubbard ladder with long range anti-ferromagnetic order (United States)

    Yang, Chun; Feiguin, Adrian

    We study the spectral properties of a Hubbard ladder with anti-ferromagnetic long range order by introducing a staggered Heisenberg interaction that decays algebraically. Unlike an alternating field or the t -Jz model, our problem preserves both SU (2) and translational invariance. We solve the problem with the time-dependent density matrix renormalization group and analyze the binding between holons and spinons and the structure of the elementary excitations. We discuss the implications in the context of the 2D Hubbard model at, and away from half-filling by using cluster perturbation theory (CPT). AF acknowledges the U.S. Department of Energy, Office of Basic Energy Sciences, for support under Grant DE-SC0014407.

  3. Poisson equation for the three-loop ladder diagram in string theory at genus one (United States)

    Basu, Anirban


    The three-loop ladder diagram is a graph with six links and four cubic vertices that contributes to the D12ℛ4 amplitude at genus one in type II string theory. The vertices represent the insertion points of vertex operators on the toroidal worldsheet and the links represent scalar Green functions connecting them. By using the properties of the Green function and manipulating the various expressions, we obtain a modular invariant Poisson equation satisfied by this diagram, with source terms involving one-, two- and three-loop diagrams. Unlike the source terms in the Poisson equations for diagrams at lower orders in the momentum expansion or the Mercedes diagram, a particular source term involves a five-point function containing a holomorphic and a antiholomorphic worldsheet derivative acting on different Green functions. We also obtain simple equalities between topologically distinct diagrams, and consider some elementary examples.

  4. Distance Teaching on Bornholm

    DEFF Research Database (Denmark)

    Hansen, Finn J. S.; Clausen, Christian


    The case study represents an example of a top-down introduction of distance teaching as part of Danish trials with the introduction of multimedia in education. The study is concerned with the background, aim and context of the trial as well as the role and working of the technology and the organi......The case study represents an example of a top-down introduction of distance teaching as part of Danish trials with the introduction of multimedia in education. The study is concerned with the background, aim and context of the trial as well as the role and working of the technology...

  5. Climbing the "ladder of participation": engaging experiential youth in a participatory research project. (United States)

    Funk, Anna; Van Borek, Natasha; Taylor, Darlene; Grewal, Puneet; Tzemis, Despina; Buxton, Jane


    Street-involved youth are at high risk for acquiring HIV and hepatitis C infection due to potential engagement in high-risk behaviours, including injection drug use. The Youth Injection Prevention (YIP) Project sought to identify factors that prevented street-involved youth from moving into injection drug use in Vancouver, BC. Our project used a participatory research orientation to study these factors. This paper describes the level of participation observed among the street-involved youth taking part in our project. The YIP project employed street-involved youth as co-researchers. To assess the level of participation among the co-researchers, we applied Roger Hart's "Ladder of Youth Participation". Each advancing rung in the ladder represents a higher level of participation. We compared the youth's involvement in the project to the rungs in Roger Hart's tool. Throughout the duration of the project, the youth's participation increased. Initially the youth had low levels of participation as they were hired based on their life experiences and initially consulted and informed. Over the course of the project, team- and skill-building activities took place. This helped the project environment evolve into a safe space where youth felt comfortable to engage at the highest levels of participation. The YIP Project was successful in being a highly participatory research project. In a safe and open environment, the youth felt comfortable to question and take on initiatives that went beyond the academic researcher's initial expectations. This project highlights the success of engaging street-involved youth in participatory research.

  6. Cocaine is low on the value ladder of rats: possible evidence for resilience to addiction.

    Directory of Open Access Journals (Sweden)

    Lauriane Cantin

    Full Text Available BACKGROUND: Assessing the relative value of cocaine and how it changes with chronic drug use represents a long-standing goal in addiction research. Surprisingly, recent experiments in rats--by far the most frequently used animal model in this field--suggest that the value of cocaine is lower than previously thought. METHODOLOGY/PRINCIPAL FINDINGS: Here we report a series of choice experiments that better define the relative position of cocaine on the value ladder of rats (i.e., preference rank-ordering of different rewards. Rats were allowed to choose either taking cocaine or drinking water sweetened with saccharin--a nondrug alternative that is not biologically essential. By systematically varying the cost and concentration of sweet water, we found that cocaine is low on the value ladder of the large majority of rats, near the lowest concentrations of sweet water. In addition, a retrospective analysis of all experiments over the past 5 years revealed that no matter how heavy was past cocaine use most rats readily give up cocaine use in favor of the nondrug alternative. Only a minority, fewer than 15% at the heaviest level of past cocaine use, continued to take cocaine, even when hungry and offered a natural sugar that could relieve their need of calories. CONCLUSIONS/SIGNIFICANCE: This pattern of results (cocaine abstinence in most rats; cocaine preference in few rats maps well onto the epidemiology of human cocaine addiction and suggests that only a minority of rats would be vulnerable to cocaine addiction while the large majority would be resilient despite extensive drug use. Resilience to drug addiction has long been suspected in humans but could not be firmly established, mostly because it is difficult to control retrospectively for differences in drug self-exposure and/or availability in human drug users. This conclusion has important implications for preclinical research on the neurobiology of cocaine addiction and for future medication

  7. Rapport in Distance Education (United States)

    Murphy, Elizabeth; Rodriguez-Manzanares, Maria A.


    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…

  8. Encyclopedia of Distance Learning (United States)

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


    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…

  9. Electromagnetic distance measurement

    CERN Document Server


    This book brings together the work of forty-eight geodesists from twenty-five countries. They discuss various new electromagnetic distance measurement (EDM) instruments - among them the Tellurometer, Geodimeter, and air- and satellite-borne systems - and investigate the complex sources of error.

  10. De-severing distance

    DEFF Research Database (Denmark)

    Jensen, Hanne Louise; de Neergaard, Maja


    De-severing Distance This paper draws on the growing body of mobility literature that shows how mobility can be viewed as meaningful everyday practices (Freudendal –Pedersen 2007, Cresswell 2006) this paper examines how Heidegger’s term de-severing can help us understand the everyday coping with ...

  11. A Baker-Campbell-Hausdorff solution by differential equation

    International Nuclear Information System (INIS)

    Lee, Hyun Keun


    We propose a procedure to figure out the Baker-Campbell-Hausdorff (BCH) solution, ln e X e Y , when the exponent is a linear combination of the spin operator along a direction and its ladder operators. The procedure converts the manipulation of the BCH formula into that of a differential equation. It is shown that the fixed point of the differential equation leads to the solution we are looking for. We also remark that the validity of the present method is restricted to the case when the solution branch can be determined in the complex plane

  12. Effect of Geographic Distance on Distance Education: An Empirical Study (United States)

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


    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. Selection of an experimental fish ladder located at the dam of the Itaipu Binacional, Paraná River, Brazil

    Directory of Open Access Journals (Sweden)

    Domingo Rodriguez Fernandez


    Full Text Available The specific selection of a weir and orifice type experimental fish ladder in the dam of the Itaipu Reservoir (Paraná River was evaluated by samplings in the river downstream and at two points along the ladder (at heights of 10 m and 27 m during 28 months. Among the 65 species recorded in the river (immediate downstream of the dam, 27 were captured on the ladder. The species that showed highest density on the ladder, the majority migratory, were moderately, or only slightly, abundant downstream. Among the most abundant species downstream, only one, non-migratory, was recorded in the ladder. The structure presented a negative selection in relation to large migratory pimelodids that might be overcome by enlarging the scale of its design. The sampling demonstrated a moderate selection of species along the ladder and its hydraulic model proved satisfactory regarding the attraction and efficient ascent of the fishes.A seleção específica de uma escada de peixes do tipo seqüência de tanques, com passagem de fundo (tipo weir and orifice, na barragem da hidrelétrica de Itaipu (rio Paraná, foi avaliada através de amostragens no rio a jusante (amostragem trimestral em 1997 e em dois pontos ao longo da escada (10 e 27m de altura; nov/94 a jan/97 e nov/94 a fev/97, respectivamente. Das 65 espécies registradas no rio imediatamente a jusante da barragem, 27 foram capturadas na escada. As espécies com maior densidade na escada, em sua maioria migradoras, tiveram abundância moderada ou baixa a jusante. Entre as mais abundantes a jusante, apenas uma, não migradora, foi registrada na escada. A escada apresentou seleção negativa aos grandes pimelodídeos migradores que pode ser superada com a ampliação na escala do projeto. As amostragens evidenciaram baixa seletividade específica ao longo da escada, sendo seu modelo hidráulico satisfatório na atração e eficiente na ascensão de peixes.

  14. Distance between images (United States)

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


    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.


    International Nuclear Information System (INIS)

    Tully, R. Brent; Courtois, Helene M.; Jacobs, Bradley A.; Rizzi, Luca; Shaya, Edward J.; Makarov, Dmitry I.


    A database can be accessed on the Web at that was developed to promote access to information related to galaxy distances. The database has three functional components. First, tables from many literature sources have been gathered and enhanced with links through a distinct galaxy naming convention. Second, comparisons of results both at the levels of parameters and of techniques have begun and are continuing, leading to increasing homogeneity and consistency of distance measurements. Third, new material is presented arising from ongoing observational programs at the University of Hawaii 2.2 m telescope, radio telescopes at Green Bank, Arecibo, and Parkes and with the Hubble Space Telescope. This new observational material is made available in tandem with related material drawn from archives and passed through common analysis pipelines.

  16. Distance, Borders, and Time

    DEFF Research Database (Denmark)

    Skillicorn, David; Walther, Olivier; Zheng, Quan

    is a combination of the physical geography of the target environment, and the mental and physical cost of following a seemingly random pattern of attacks. Focusing on the distance and time between attacks and taking into consideration the transaction costs that state boundaries impose, we wish to understand what......” of North and West Africa that depicts the permeability to violence. A better understanding of how location, time, and borders condition attacks enables planning, prepositioning, and response....

  17. Distant metastases of differentiated thyroid cancer. Diagnosis by 131 iodine and treatment; Metastases a distance des cancers thyroidiens differencies. Diagnostic par l`iode 131 (I 131) et traitement

    Energy Technology Data Exchange (ETDEWEB)

    Leger, A.F. [Hopital Necker-Enfants-Malades, 75 - Paris (France)


    Distant metastases in differentiated thyroid cancer involve mainly lung and bone. Lung metastases were found in 5% of papillary forms and 10% of follicular forms respectively. I 131 uptake was found in 55% of the cases irrespective of histology. Bone metastases were found in 20% of follicular and 3.5% of papillary forms, respectively. Ablation of post-operative thyroid remnants is obtained by administering 3.7 GBq I 131; I 131 (.2 to .4 GBq) is then used to localize distant metastases and a further 3.7 to 7.4 GBq is administered for therapy. Results are good in lung metastases, with a survival of 72% at 5 years. Bone metastases cannot be cured with I 131 alone. Surgery is indicated as a first line therapy if possible. In order to reduce the vascularization of the metastases a pre-operative embolization should be attempted. After bone surgery a therapeutic dose of I 131 is given if a post-operative I 131 uptake is found. Others treatments of bone metastases are palliative surgery, external radiotherapy, cementing of the metastases. (author). 6 refs.

  18. Electronically Tunable Current-mode High-order Ladder Low-pass Filters Based on CMOS Technology

    Directory of Open Access Journals (Sweden)

    T. Kunto


    Full Text Available This paper describes the design of current mode low-pass ladder filters based on CMOS technology. The filters are derived from passive RLC ladder filter prototypes using new CMOS lossy and lossless integrators. The all-pole and Elliptic approximations are used in the proposed low-pass filter realizations. The proposed two types of filter can be electronically tuned between 10kHz and 100MHz through bias current from 0.03µA to 300µA. The proposed filters use 1.5 V power supply with 3 mW power consumption at 300 µA bias current. The proposed filters are resistorless, use grounded capacitors and are suitable for further integration. The total harmonic distortion (THD of the low-pass filters is less than 1% over the operating frequency range. PSPICE simulation results, obtained by using TSMC 0.18µm technology, confirm the presented theory.

  19. The pressure effects on the antiferromagentic orders in iron-based ladder compounds BaFe2S3 (United States)

    Chi, Songxue; Uwatoko, Yoshiya; Hirata, Yasuyuki; Ohgushi, Kenya

    The ladder compounds have recently become a new test ground for the studies on Fe-based superconductors. The building block for such materials, the two-leg Fe ladder surrounded by edge-sharing chalcogen tetrahedra, has provided a quasi-one-dimensional channel for the remaining critical issues in this field. Recently, superconductivity was successfully induced by pressure in one of such compounds, BaFe2S3. The knowledge of the pressure effect on its antiferromagnetic order is crucial in understanding the superconductivity in the low-dimensional system. I will present the results of our neutron diffraction studies on the evolution of the magnetic phase under hydraulic pressure in single crystalline BaFe2S3.

  20. New phenazine-containing ladder polymer of intrinsic microporosity from a spirobisindane-based AB-type monomer

    KAUST Repository

    Ghanem, Bader


    A new solution-processable ladder polymer (PSBI-AB) of intrinsic microporosity with dibenzodioxane linkages and bis(phenazine) units was designed and synthesized by self-polymerization of an AB-type monomer containing both catechol and aromatic dichloride groups. Such polymerization is an effective way to synthesize high molecular weight polymers and has a significant advantage over AA-BB polycondensation due to the lack of the requirement for strict control over stoichiometric balance. This protocol can be used to prepare a variety of phenazine-containing ladder type PIMs from their aromatic tetramethoxy precursors. The obtained polymer had high average molecular mass, excellent thermal stability, a high BET surface area of 705 m(2) g(-1) and good solubility in some organic solvents such as chloroform, m-cresol and dichlorobenzene. Gas permeation measurements showed comparable results to the previously reported analogous PIM-7 for films made under the same formation protocol.

  1. Dynamics of blood flow and thrombus formation in a multi-bypass microfluidic ladder network. (United States)

    Zilberman-Rudenko, Jevgenia; Sylman, Joanna L; Lakshmanan, Hari H S; McCarty, Owen J T; Maddala, Jeevan


    The reaction dynamics of a complex mixture of cells and proteins, such as blood, in branched circulatory networks within the human microvasculature or extravascular therapeutic devices such as extracorporeal oxygenation machine (ECMO) remains ill-defined. In this report we utilize a multi-bypass microfluidics ladder network design with dimensions mimicking venules to study patterns of blood platelet aggregation and fibrin formation under complex shear. Complex blood fluid dynamics within multi-bypass networks under flow were modeled using COMSOL. Red blood cells and platelets were assumed to be non-interacting spherical particles transported by the bulk fluid flow, and convection of the activated coagulation factor II, thrombin, was assumed to be governed by mass transfer. This model served as the basis for predicting formation of local shear rate gradients, stagnation points and recirculation zones as dictated by the bypass geometry. Based on the insights from these models, we were able to predict the patterns of blood clot formation at specific locations in the device. Our experimental data was then used to adjust the model to account for the dynamical presence of thrombus formation in the biorheology of blood flow. The model predictions were then compared to results from experiments using recalcified whole human blood. Microfluidic devices were coated with the extracellular matrix protein, fibrillar collagen, and the initiator of the extrinsic pathway of coagulation, tissue factor. Blood was perfused through the devices at a flow rate of 2 µL/min, translating to physiologically relevant initial shear rates of 300 and 700 s -1 for main channels and bypasses, respectively. Using fluorescent and light microscopy, we observed distinct flow and thrombus formation patterns near channel intersections at bypass points, within recirculation zones and at stagnation points. Findings from this proof-of-principle ladder network model suggest a specific correlation between

  2. Double-helical - ladder structural transition in the B-DNA is induced by a loss of dispersion energy

    Czech Academy of Sciences Publication Activity Database

    Černý, Jiří; Kabeláč, Martin; Hobza, Pavel


    Roč. 130, č. 47 (2008), s. 16055-16059 ISSN 0002-7863 R&D Projects: GA MŠk LC512; GA AV ČR IAA400550808 Institutional research plan: CEZ:AV0Z40550506 Keywords : B-DNA * double-helical structure * ladder-like structure Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 8.091, year: 2008

  3. Pressure-induced superconductivity in the iron-based ladder material BaFe2S3. (United States)

    Takahashi, Hiroki; Sugimoto, Akira; Nambu, Yusuke; Yamauchi, Touru; Hirata, Yasuyuki; Kawakami, Takateru; Avdeev, Maxim; Matsubayashi, Kazuyuki; Du, Fei; Kawashima, Chizuru; Soeda, Hideto; Nakano, Satoshi; Uwatoko, Yoshiya; Ueda, Yutaka; Sato, Taku J; Ohgushi, Kenya


    All the iron-based superconductors identified so far share a square lattice composed of Fe atoms as a common feature, despite having different crystal structures. In copper-based materials, the superconducting phase emerges not only in square-lattice structures but also in ladder structures. Yet iron-based superconductors without a square-lattice motif have not been found, despite being actively sought out. Here, we report the discovery of pressure-induced superconductivity in the iron-based spin-ladder material BaFe2S3, a Mott insulator with striped-type magnetic ordering below ∼120 K. On the application of pressure this compound exhibits a metal-insulator transition at about 11 GPa, followed by the appearance of superconductivity below Tc = 14 K, right after the onset of the metallic phase. Our findings indicate that iron-based ladder compounds represent promising material platforms, in particular for studying the fundamentals of iron-based superconductivity.

  4. Academic Profile of Bachelor of Technical Teacher Education Ladder I Students as Ba sis for an Intervention Program

    Directory of Open Access Journals (Sweden)

    Arly B. Balingbing


    Full Text Available This study aimed to determine: the academic profile of Bachelor of Technical Teacher Education ( BTTE Ladder 1 students in terms of entrance examination, GWM in GEC subjects and TESDA Competency Assessment; their strengths and weaknesses along TESDA Assessment; the significant relationship between Entrance Examination & GWA, GWA & TESDA Competency and Entrance Examination & TESDA Compe tency, the significant interrelationship among the three variables; and the program or intervention which could be proposed to improve their academic performance. Data were gathered from one hundred fifty eight ( 158 BTTE Ladder 1 graduates of SY 2014 - 2016 through a questionnaire and documentary analysis and were statistically treated using percentage, weighted mean, Spearman’s rho and multiple coefficients. The researcher concluded that BTTE Ladder 1 students are competent as assessed by TESDA despite bein g low in entrance examination. Their weaknesses lie along communication and comprehension but they prove to be capable also on the condition that Filipino language is used and questions are repeated or rephrased. They also lack exposure to the tools and eq uipment used their field. Their strength is evident in performing the task but not in explaining the process. Both the Entrance Examination & GWA, GWM & TESDA Competency and Entrance Exam & TESDA Competency are significantly interrelated.

  5. Extra-galactic Distances with Massive Stars: The Role of Stellar Variability in the Case of M33

    Energy Technology Data Exchange (ETDEWEB)

    Lee Chien-Hsiu, E-mail: [Subaru Telescope, NAOJ, 650 N Aohoku Pl, Hilo, HI 96720 (United States)


    In modern cosmology, determining the Hubble constant (H{sub 0}) using a distance ladder to percent level and comparing with the results from the Planck  satellite can shed light on the nature of dark energy, physics of the neutrino, and curvature of the universe. Thanks to the endeavor of the SH0ES team, the uncertainty of the H{sub 0} has be dramatically reduced, from 10% to 2.4%, and with the promise of even reaching 1% in the near future. In this regard, it is fundamentally important to investigate the systematics. This is best done using other good independent distance indicators. One promising method is the flux-weighted gravity luminosity relation (FGLR) of the blue supergiants (BSGs). As BSGs are the brightest objects in galaxies, they can probe distances up to 10 Mpc with negligible blending effects. While the FGLR method delivered distance is in good agreement with other distance indicators, it has been shown that this method delivers greater distances in the cases of M33 and NGC 55. Here, we investigate whether the M33 distance estimate of FGLR suffers systematics from stellar variability. Using CFHT M33 monitoring data, we found that 9 out of 22 BSGs showed variability during the course of 500 days, although with amplitudes as small as 0.05 mag. This suggests that stellar variability plays a negligible role in the FGLR distance determination.

  6. Extra-galactic Distances with Massive Stars: The Role of Stellar Variability in the Case of M33 (United States)

    Lee, Chien-Hsiu


    In modern cosmology, determining the Hubble constant (H0) using a distance ladder to percent level and comparing with the results from the Planck satellite can shed light on the nature of dark energy, physics of the neutrino, and curvature of the universe. Thanks to the endeavor of the SH0ES team, the uncertainty of the H0 has be dramatically reduced, from 10% to 2.4%, and with the promise of even reaching 1% in the near future. In this regard, it is fundamentally important to investigate the systematics. This is best done using other good independent distance indicators. One promising method is the flux-weighted gravity luminosity relation (FGLR) of the blue supergiants (BSGs). As BSGs are the brightest objects in galaxies, they can probe distances up to 10 Mpc with negligible blending effects. While the FGLR method delivered distance is in good agreement with other distance indicators, it has been shown that this method delivers greater distances in the cases of M33 and NGC 55. Here, we investigate whether the M33 distance estimate of FGLR suffers systematics from stellar variability. Using CFHT M33 monitoring data, we found that 9 out of 22 BSGs showed variability during the course of 500 days, although with amplitudes as small as 0.05 mag. This suggests that stellar variability plays a negligible role in the FGLR distance determination.

  7. System-wide analysis of the transcriptional network of human myelomonocytic leukemia cells predicts attractor structure and phorbol-ester-induced differentiation and dedifferentiation transitions (United States)

    Sakata, Katsumi; Ohyanagi, Hajime; Sato, Shinji; Nobori, Hiroya; Hayashi, Akiko; Ishii, Hideshi; Daub, Carsten O.; Kawai, Jun; Suzuki, Harukazu; Saito, Toshiyuki


    We present a system-wide transcriptional network structure that controls cell types in the context of expression pattern transitions that correspond to cell type transitions. Co-expression based analyses uncovered a system-wide, ladder-like transcription factor cluster structure composed of nearly 1,600 transcription factors in a human transcriptional network. Computer simulations based on a transcriptional regulatory model deduced from the system-wide, ladder-like transcription factor cluster structure reproduced expression pattern transitions when human THP-1 myelomonocytic leukaemia cells cease proliferation and differentiate under phorbol myristate acetate stimulation. The behaviour of MYC, a reprogramming Yamanaka factor that was suggested to be essential for induced pluripotent stem cells during dedifferentiation, could be interpreted based on the transcriptional regulation predicted by the system-wide, ladder-like transcription factor cluster structure. This study introduces a novel system-wide structure to transcriptional networks that provides new insights into network topology.

  8. Distance collaborations with industry

    Energy Technology Data Exchange (ETDEWEB)

    Peskin, A.; Swyler, K.


    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.

  9. The ladder rung walking task: a scoring system and its practical application. (United States)

    Metz, Gerlinde A; Whishaw, Ian Q


    Progress in the development of animal models for/stroke, spinal cord injury, and other neurodegenerative disease requires tests of high sensitivity to elaborate distinct aspects of motor function and to determine even subtle loss of movement capacity. To enhance efficacy and resolution of testing, tests should permit qualitative and quantitative measures of motor function and be sensitive to changes in performance during recovery periods. The present study describes a new task to assess skilled walking in the rat to measure both forelimb and hindlimb function at the same time. Animals are required to walk along a horizontal ladder on which the spacing of the rungs is variable and is periodically changed. Changes in rung spacing prevent animals from learning the absolute and relative location of the rungs and so minimize the ability of the animals to compensate for impairments through learning. In addition, changing the spacing between the rungs allows the test to be used repeatedly in long-term studies. Methods are described for both quantitative and qualitative description of both fore- and hindlimb performance, including limb placing, stepping, co-ordination. Furthermore, use of compensatory strategies is indicated by missteps or compensatory steps in response to another limb's misplacement.

  10. Super (a, d)-Cycle-Antimagic Total Labeling on Triangular Ladder Graph and Generalized Jahangir Graph (United States)

    Roswitha, Mania; Amanda, Anna; Sri Martini, Titin; Winarno, Bowo


    Let G(V (G), E(G)) be a finite simple graph with |V (G)| = G and |E(G)| = eG . Let H be a subgraph of G. The graph G is said to be (a, d)-H-antimagic covering if every edge in G belongs to at least one of the subgraphs G isomorphic to H and there is a bijective function ξ : V ∪ E → {1, 2, …,νG + eG } such that all subgraphs H‧ isomorphic to H, the H‧ -weights w(H‧)=∑v∈V(H‧)ξ(v)+∑e∈E(H‧)ξ(e) constitutes an arithmetic progression {a, a + d, a + 2d, …, a + (t - 1)d}, where a and d are positive integers and t is the number of subgraphs G isomorphic to H. Such a labeling is called super if the vertices contain the smallest possible labels. This research provides super (a, d)-C 3-antimagic total labelng on triangular ladder TLn for n ≥ 2 and super (a, d)-C s+2-antimagic total labeling on generalized Jahangir Jk,s for k ≥ 2 and s ≥ 2.

  11. Elementary excitations and thermodynamics of zig-zag spin ladders with alternating nearest neighbor exchange interactions

    International Nuclear Information System (INIS)

    Zvyagin, A.A.; Cheranovskii, V.O.


    A one-dimensional spin-1/2 model in which the alternation of the exchange interactions between neighboring spins is accompanied by the next-nearest-neighbor (NNN) spin exchange (zig-zag spin ladder with alternation) is studied. The thermodynamic characteristics of the model quantum spin chain are obtained in the mean-field-like approximation. Depending on the strength of the NNN interactions, the model manifests either the spin-gapped behavior of low-lying excitations at low magnetic fields, or ferrimagnetic ordering in the ground state with gapless low-lying excitations. The system undergoes second-order or first-order quantum phase transitions, governed by the external magnetic field, NNN coupling strength, and the degree of the alternation. Hence, NNN spin-spin interactions in a dimerized quantum spin chain can produce a spontaneous magnetization. On the other hand, for quantum spin chains with a spontaneous magnetization, caused by NNN spin-spin couplings, the alternation of nearest-neighbor (NN) exchange interactions can cause destruction of that magnetization and the onset of a spin gap for low-lying excitations. Alternating NN interactions produce a spin gap between two branches of low-energy excitations, and the NNN interactions yield asymmetry of the dispersion laws of those excitations, with possible minima corresponding to incommensurate structures in the spin chain

  12. Signatures of pairing in the magnetic excitation spectrum of strongly correlated two-leg ladders (United States)

    Nocera, A.; Patel, N. D.; Dagotto, E.; Alvarez, G.


    Magnetic interactions are widely believed to play a crucial role in the microscopic mechanism leading to high critical temperature superconductivity. It is therefore important to study the signatures of pairing in the magnetic excitation spectrum of simple models known to show unconventional superconducting tendencies. Using the density matrix renormalization group technique, we calculate the dynamical spin structure factor S (k ,ω ) of a generalized t -U -J Hubbard model away from half filling in a two-leg ladder geometry. The addition of J enhances pairing tendencies. We analyze quantitatively the signatures of pairing in the magnetic excitation spectra. We found that the superconducting pair-correlation strength, that can be estimated independently from ground state properties, is closely correlated with the integrated low-energy magnetic spectral weight in the vicinity of (π ,π ) . In this wave-vector region, robust spin incommensurate features develop with increasing doping. The branch of the spectrum with rung direction wave vector krung=0 does not change substantially with doping where pairing dominates and thus plays a minor role. We discuss the implications of our results for neutron scattering experiments, where the spin excitation dynamics of hole-doped quasi-one-dimensional magnetic materials can be measured and also address implications for recent resonant inelastic x-ray scattering experiments.

  13. Fully frustrated Josephson junction ladders with Mobius boundary conditions as topologically protected qubits

    Energy Technology Data Exchange (ETDEWEB)

    Cristofano, Gerardo; Marotta, Vincenzo [Dipartimento di Scienze Fisiche, Universita di Napoli ' Federico II' and INFN, Sezione di Napoli, Via Cintia, Complesso Universitario M. Sant' Angelo, 80126 Napoli (Italy); Naddeo, Adele [Dipartimento di Fisica ' E.R. Caianiello' , Universita degli Studi di Salerno and CNISM, Unita di Ricerca di Salerno, Via Salvador Allende, 84081 Baronissi (Saudi Arabia) (Italy)], E-mail:; Niccoli, Giuliano [LPTM, Universite de Cergy-Pontoise, 2 avenue Adolphe Chauvin, 95302 Cergy-Pontoise (France)


    We show how to realize a 'protected' qubit by using a fully frustrated Josephson junction ladder (JJL) with Mobius boundary conditions. Such a system has been recently studied within a twisted conformal field theory (CFT) approach [G. Cristofano, G. Maiella, V. Marotta, Mod. Phys. Lett. A 15 (2000) 1679; G. Cristofano, G. Maiella, V. Marotta, G. Niccoli, Nucl. Phys. B 641 (2002) 547] and shown to develop the phenomenon of flux fractionalization [G. Cristofano, V. Marotta, A. Naddeo, G. Niccoli, Eur. Phys. J. B 49 (2006) 83]. The relevance of a 'closed' geometry has been fully exploited in relating the topological properties of the ground state of the system to the presence of half flux quanta and the emergence of a topological order has been predicted [G. Cristofano, V. Marotta, A. Naddeo, J. Stat. Mech.: Theory Exp. (2005) P03006]. In this Letter the stability and transformation properties of the ground states under adiabatic magnetic flux change are analyzed and the deep consequences on the realization of a solid state qubit, protected from decoherence, are presented.

  14. Resonant two-photon absorption and electromagnetically induced transparency in open ladder-type atomic system. (United States)

    Moon, Han Seb; Noh, Heung-Ryoul


    We have experimentally and theoretically studied resonant two-photon absorption (TPA) and electromagnetically induced transparency (EIT) in the open ladder-type atomic system of the 5S(1/2) (F = 1)-5P(3/2) (F' = 0, 1, 2)-5D(5/2) (F″ = 1, 2, 3) transitions in (87)Rb atoms. As the coupling laser intensity was increased, the resonant TPA was transformed to EIT for the 5S(1/2) (F = 1)-5P(3/2) (F' = 2)-5D(5/2) (F″ = 3) transition. The transformation of resonant TPA into EIT was numerically calculated for various coupling laser intensities, considering all the degenerate magnetic sublevels of the 5S(1/2)-5P(3/2)-5D(5/2) transition. From the numerical results, the crossover from TPA to EIT could be understood by the decomposition of the spectrum into an EIT component owing to the pure two-photon coherence and a TPA component caused by the mixed term.

  15. Are contemporary tourists consuming distance?

    DEFF Research Database (Denmark)

    Larsen, Gunvor Riber

    , because mobilities are not equal (Manderscheid, 2009; Kaufmann 2002; Gogia 2006). A hundred miles ceases to be 'just' a hundred miles when the questions of why and how this distance is to be overcome is being asked, making the social context of the individual important for the impact of having to overcome...... distance. Without the social contexts of those 'performing mobility' distance is indeed just distance, a hundred miles is a hundred miles where-ever it is, but for meaningful social inquiries into mobilities, the social contexts cannot be omitted. It is the distance that is embedded in the social contexts....... Following from the above, distance is not solely understood and represented by euclidean units such as meters or miles, and distance will have varying degrees of impact on individuals according to their social and economic contexts. Tourism mobility and distance are linked through a spatial necessity...

  16. Continuing Education for Distance Librarians (United States)

    Cassner, Mary; Adams, Kate E.


    Distance librarians as engaged professionals work in a complex environment of changes in technologies, user expectations, and institutional goals. They strive to keep current with skills and competencies to support distance learners. This article provides a selection of continuing education opportunities for distance librarians, and is relevant…

  17. Exact expression for information distance

    NARCIS (Netherlands)

    P.M.B. Vitányi (Paul)


    textabstractInformation distance can be defined not only between two strings but also in a finite multiset of strings of cardinality greater than two. We determine a best upper bound on the information distance. It is exact, since the upper bound on the information distance for all multisets is the


    International Nuclear Information System (INIS)

    Foster, Jonathan B.; Jackson, James M.; Stead, Joseph J.; Hoare, Melvin G.; Benjamin, Robert A.


    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.


    Energy Technology Data Exchange (ETDEWEB)

    Foster, Jonathan B.; Jackson, James M. [Institute for Astrophysical Research, Boston University, Boston, MA 02215 (United States); Stead, Joseph J.; Hoare, Melvin G. [School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT (United Kingdom); Benjamin, Robert A., E-mail:, E-mail:, E-mail:, E-mail:, E-mail: [Physics Department, University of Wisconsin Whitewater, Whitewater, WI 53190 (United States)


    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.

  20. Distances to Dark Clouds: Comparing Extinction Distances to Maser Parallax Distances (United States)

    Foster, Jonathan B.; Stead, Joseph J.; Benjamin, Robert A.; Hoare, Melvin G.; Jackson, James M.


    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.

  1. Information Distances versus Entropy Metric

    Directory of Open Access Journals (Sweden)

    Bo Hu


    Full Text Available Information distance has become an important tool in a wide variety of applications. Various types of information distance have been made over the years. These information distance measures are different from entropy metric, as the former is based on Kolmogorov complexity and the latter on Shannon entropy. However, for any computable probability distributions, up to a constant, the expected value of Kolmogorov complexity equals the Shannon entropy. We study the similar relationship between entropy and information distance. We also study the relationship between entropy and the normalized versions of information distances.

  2. Towards an intelligent environment for distance learning

    Directory of Open Access Journals (Sweden)

    Rafael Morales


    Full Text Available Mainstream distance learning nowadays is heavily influenced by traditional educational approaches that produceshomogenised learning scenarios for all learners through learning management systems. Any differentiation betweenlearners and personalisation of their learning scenarios is left to the teacher, who gets minimum support from the system inthis respect. This way, the truly digital native, the computer, is left out of the move, unable to better support the teachinglearning processes because it is not provided with the means to transform into knowledge all the information that it storesand manages. I believe learning management systems should care for supporting adaptation and personalisation of bothindividual learning and the formation of communities of learning. Open learner modelling and intelligent collaborativelearning environments are proposed as a means to care. The proposal is complemented with a general architecture for anintelligent environment for distance learning and an educational model based on the principles of self-management,creativity, significance and participation.

  3. On the Luminosity Distance and the Hubble Constant


    Yuri Heymann


    By differentiating luminosity distance with respect to time using its standard formula we find that the peculiar velocity is a time varying velocity of light. Therefore, a new definition of the luminosity distance is provided such that the peculiar velocity is equal to c. Using this definition a Hubble constant H0 = 67.3 km s−1 Mpc−1 is obtained from supernovae data.

  4. Fast computation of distance estimators

    Directory of Open Access Journals (Sweden)

    Lagergren Jens


    Full Text Available Abstract Background Some distance methods are among the most commonly used methods for reconstructing phylogenetic trees from sequence data. The input to a distance method is a distance matrix, containing estimated pairwise distances between all pairs of taxa. Distance methods themselves are often fast, e.g., the famous and popular Neighbor Joining (NJ algorithm reconstructs a phylogeny of n taxa in time O(n3. Unfortunately, the fastest practical algorithms known for Computing the distance matrix, from n sequences of length l, takes time proportional to l·n2. Since the sequence length typically is much larger than the number of taxa, the distance estimation is the bottleneck in phylogeny reconstruction. This bottleneck is especially apparent in reconstruction of large phylogenies or in applications where many trees have to be reconstructed, e.g., bootstrapping and genome wide applications. Results We give an advanced algorithm for Computing the number of mutational events between DNA sequences which is significantly faster than both Phylip and Paup. Moreover, we give a new method for estimating pairwise distances between sequences which contain ambiguity Symbols. This new method is shown to be more accurate as well as faster than earlier methods. Conclusion Our novel algorithm for Computing distance estimators provides a valuable tool in phylogeny reconstruction. Since the running time of our distance estimation algorithm is comparable to that of most distance methods, the previous bottleneck is removed. All distance methods, such as NJ, require a distance matrix as input and, hence, our novel algorithm significantly improves the overall running time of all distance methods. In particular, we show for real world biological applications how the running time of phylogeny reconstruction using NJ is improved from a matter of hours to a matter of seconds.

  5. Planning with Reachable Distances

    KAUST Repository

    Tang, Xinyu


    Motion planning for spatially constrained robots is difficult due to additional constraints placed on the robot, such as closure constraints for closed chains or requirements on end effector placement for articulated linkages. It is usually computationally too expensive to apply sampling-based planners to these problems since it is difficult to generate valid configurations. We overcome this challenge by redefining the robot\\'s degrees of freedom and constraints into a new set of parameters, called reachable distance space (RD-space), in which all configurations lie in the set of constraint-satisfying subspaces. This enables us to directly sample the constrained subspaces with complexity linear in the robot\\'s number of degrees of freedom. In addition to supporting efficient sampling, we show that the RD-space formulation naturally supports planning, and in particular, we design a local planner suitable for use by sampling-based planners. We demonstrate the effectiveness and efficiency of our approach for several systems including closed chain planning with multiple loops, restricted end effector sampling, and on-line planning for drawing/sculpting. We can sample single-loop closed chain systems with 1000 links in time comparable to open chain sampling, and we can generate samples for 1000-link multi-loop systems of varying topology in less than a second. © 2009 Springer-Verlag.

  6. Encyclopedia of Distance Learning

    Directory of Open Access Journals (Sweden)



    Full Text Available Encyclopedia of Distance Learning reference book published by Idea Group consists of four volumes. The encyclopedia edited by 6 editors of whom the five are from USA and one is from Hong Kong. Besides these editors, 19 advisors have supported the encyclopedia. The editors and the advisory board are from different institutions. There are more than 400 contributors to the book. Although majority of the contributors are from USA, there are several contributors from several Asian, European and Australian countries like Hong Kong, Malaysia, Germany, Australia, Turkey, Singapore, and Belgium. All of the contributors are academics and represent a variety of universities. All volumes have editorial advisory board list, list of authors, editors’ prefaces, publisher’s note, editors’ biographies, a foreword, contents, an index and a key terms index. There are more than 3000 terms and definitions and over 6000 additional references through four volumes. This four volume set encyclopedia are ordered alphabetically. Volume I consists of initials from A to C, Volume II consists of initials from D to H, Volume III consists of initials from I to Q and Volume IV consists of initials from R to Z.

  7. Coping with Distances

    DEFF Research Database (Denmark)

    Bærenholdt, Jørgen Ole

    Coping with distances - Producing Nordic Atlantic Societies Mennesker håndterer afstande og producerer derved samfund. Dette er det grundlæggende synspunkt i en afhandling, hvor samfund ikke tages for givet. Samfund er tværtimod noget som hele tiden må produceres, genproduceres og forandres, og det...... været afgørende. Afhandlingen tages sit afsæt i en teoretisk diskussion af begreberne samfund, håndtering (coping på engelsk), social kapital, territorialitet, mobilitet, bonding (stærke identitetsbærende bånd) og bridging (svage, brobyggende forbindelser). Der gås på tværs af vante skel mellem kultur...... trussel mod samfundsbygningen. Men kap. 6 viser de mange måder hvori gennem turismen bidrager til samfundsbygningen, og det er en historie som indledes med en grundig diskussion af opdagelsesrejsernes grundlæggende betydning, også kulturelt. Begge disse kapitler tilføjer coping tilgangen flere analytiske...

  8. Invariant distances and metrics in complex analysis

    CERN Document Server

    Jarnicki, Marek


    As in the field of ""Invariant Distances and Metrics in Complex Analysis"" there was and is a continuous progress this is the second extended edition of the corresponding monograph. This comprehensive book is about the study of invariant pseudodistances (non-negative functions on pairs of points) and pseudometrics (non-negative functions on the tangent bundle) in several complex variables. It is an overview over a highly active research area at the borderline between complex analysis, functional analysis and differential geometry. New chapters are covering the Wu, Bergman and several other met

  9. Microgeographic differentiation in historical Yemen inferred by morphometric distances. (United States)

    Danubio, Maria Enrica; Sanna, Emanuele; Rufo, Fabrizio; Martorella, Domenico; Vecchi, Elvira; Coppa, Alfredo


    This study analyzed the variations in space of 8 body dimensions and 11 measures of the head of 1,244 adult Yemenite males, collected in 1933/34 by Coon in Yemen and in Hadhramawt. The aim was to evaluate the presence of geographic microdifferentiation of the populations settled in the different regions of Yemen at the time. Coon sub-divided the sample into six geographical areas according to birthplace and ethnicity of the individuals: Tihamah, the Western Mountains, the Central Plateau, the South Coast, the Eastern Mountains, and Hadhramawt. The results of ANCOVA (age as covariate) show that the observed differences of all variables among the six groups were highly statistically significant. Tukey's post-hoc test reveals higher statistically significant differences among four main groups: (1) Tihamah; (2) the Western Mountains and Central Plateau; (3) the Eastern Mountains; and (4) the Southern Coast and Hadhramawt. Multiple discriminant analysis carried out using only the data of the 11 measures of the head, the more "genetically" determined variables, confirmed these differences. Indeed, the first canonical variate well separates the groups with the Tihamah, Southern Coast and Hadhramawt on the one side and the Eastern Mountains, Western Mountains and Central Plateau on the other. The second canonical variate separates the Tihamah, Western Mountains and Central Plateau from the Eastern Mountains, Southern Coast and Hadhramawt. In conclusion, the Yemenite population seems to be composed of three morphologically distinct groups and an Eastern Mountains group which is positioned between the group formed by the Southern Coast and Hadhramawt and the Western Mountains and Central Plateau group. The Tihamah is the most distant from all the other groups. These differences are probably due to the presence/absence of geographical and cultural barriers that have favored/blocked the gene flow over the years. Indeed, the entire coastal bell, through the centuries, has constituted one of the principal commercial routes between the East, Africa, and the eastern Mediterranean, while the high inland mountains have isolated the remaining communities. This data is also confirmed by genetic studies. Finally, the average height (162.6 cm) of the global Yemenite population, compared to data from the other six middle-eastern Arab countries and Egypt, was found to be 3-6 cm less. This characteristic will be further studied, analyzing variations in average height according to the different age classes in order to evaluate any possible secular changes.

  10. Urban areas as refuges from predators and flight distance of prey


    Anders Pape Møller


    Large animals have longer flight distances when approached by a potential predator than small animals, and predators therefore have longer flight distances than their prey. The ubiquitous presence of humans in urban areas selects for differential invasion by animals with short flight distances, and adaptation to urban environments results in further reductions in flight distance. Because prey are better able to cope with the proximity of humans than predators due to differences in flight dist...

  11. Surface Acoustic Bloch Oscillations, the Wannier-Stark Ladder, and Landau-Zener Tunneling in a Solid (United States)

    de Lima, M. M., Jr.; Kosevich, Yu. A.; Santos, P. V.; Cantarero, A.


    We present the experimental observation of Bloch oscillations, the Wannier-Stark ladder, and Landau-Zener tunneling of surface acoustic waves in perturbed grating structures on a solid substrate. A model providing a quantitative description of our experimental observations, including multiple Landau-Zener transitions of the anticrossed surface acoustic Wannier-Stark states, is developed. The use of a planar geometry for the realization of the Bloch oscillations and Landau-Zener tunneling allows a direct access to the elastic field distribution. The vertical surface displacement has been measured by interferometry.

  12. Phase control of group velocity in a dielectric slab doped with three-level ladder-type atoms

    International Nuclear Information System (INIS)

    Jafari, D.; Sahrai, M.; Motavalli, H.; Mahmoudi, M.


    Propagation of an electromagnetic pulse through a dielectric slab doped with three-level ladder-type atomic systems is discussed. It is shown that the group velocity of the reflected and transmitted pulses can be switched from subluminal to superluminal light propagation by the thickness of the slab or the intensity of the coupling field. Furthermore, it is found that, in the presence of quantum interference, the reflected and transmitted pulses are completely phase dependent. So, the group velocity of the reflected and transmitted pulses can only be switched from subluminal to superluminal by adjusting the relative phase of the applied fields.

  13. Hausdorff distance and image processing

    International Nuclear Information System (INIS)

    Sendov, Bl


    Mathematical methods for image processing make use of function spaces which are usually Banach spaces with integral L p norms. The corresponding mathematical models of the images are functions in these spaces. There are discussions here involving the value of p for which the distance between two functions is most natural when they represent images, or the metric in which our eyes measure the distance between the images. In this paper we argue that the Hausdorff distance is more natural to measure the distance (difference) between images than any L p norm

  14. Pallet insertion glovebox/hood control ladder diagram. Final project report

    International Nuclear Information System (INIS)

    Issaian, V.


    The pallet insertion glovebox/hood (G/H) is a special confinement space that will be designed to allow for insertion of pallets into the Stacker/Retriever (S/R) area. The S/R a large vault that is kept at negative 1 inches w.c. relative to the atmosphere and is used for the safe storage of special nuclear material. The S/R system uses a vehicle to move the special nuclear material that are placed on the pallets from the storage bins to input/output (I/O) stations and vice versa. As the name suggest the I/O stations are used to place the material into the S/R vault or to remove material from the S/R vault. The pallets are specially designed structures that will hold certain numbers of the material containers in a safe configuration. To store additional material containers, there is a need to insert additional pallets in the SIR vault. Due to the presence of radioactive contamination and the fact that the vault must be kept at a negative pressure at all times, one of the several I/O stations will be modified so that pallets could be inserted into the S/R vault. The ventilation system for the S/R area is a dedicated system that recirculates nitrogen with less than 5% oxygen by volume throughout the area while exhausting small option of the nitrogen to keep the S/R at negative 1 inches w.c. relative to the atmosphere. The rooms surrounding the G/H and the S/R area are maintained at negative of 0.3 inches w.c. relative to the outside atmosphere. Both the G/H and the control system for the G/H will be designed such that the confinement requirements of the S/R and the G/H system will not be jeopardized. A ladder diagram will be developed to illustrate the control system

  15. Tröger’s Base Ladder Polymer for Membrane-Based Hydrocarbon Separation

    KAUST Repository

    Alhazmi, Abdulrahman


    The use of polymeric membranes for natural gas separation has rapidly increased during the past three decades, particularly for carbon dioxide separation from natural gas. Another valuable application is the separation of heavy hydrocarbons from methane (fuel gas conditioning), more importantly for remote area and off-shore applications. A new potential polymeric membrane that might be utilized for natural gas separations is a Tröger’s base ladder polymer (PIM-Trip-TB-2). This glassy polymeric membrane was synthesized by the polymerization reaction of 9, 10-dimethyl-2,6 (7) diaminotriptycene with dimethoxymethane. In this research, the polymer was selected due to its high surface area and highly interconnected microporous structure. Sorption isotherms of nitrogen (N2), oxygen (O¬2), methane (CH4), carbon dioxide (CO2), ethane (C2H6), propane (C3H8), and n-butane (n-C4H10) were measured at 35 °C over a range of pressures using a Hiden Intelligent Gravimetric Analyzer, IGA. The more condensable gases (C2H6, CO2, C3H8, and n-C4H10) showed high solubility due to their high affinity to the polymer matrix. The permeation coefficients were determined for various gases at 35 °C and pressure difference of 5 bar via the constant-pressure/variable-volume method. The PIM-Trip-TB-2 film exhibited high performance for several high-impact applications, such as O2/N2, H2/N2 and H2/CH4. Also, physical aging for several gases was examined by measuring the permeability coefficients at different periods of time. Moreover, a series of mixed-gas permeation tests was performed using 2 vol.% n-C4H10/98 vol.% CH4 and the results showed similar transport characteristics to other microporous polymers with pores of less than 2 nm. The work performed in this research suggested that PIM-Trip-TB-2 is suitable for the separation of: (i) higher hydrocarbons from methane and (ii) small, non-condensable gases such as O2/N2 and H2/CH4.

  16. Designing and constructing an 100 bp DNA Ladder by combining PCR and enzyme digestion methods

    Directory of Open Access Journals (Sweden)

    Saidijam M


    forward and reverse primers at the flanking region of pTZ57R multiple cloning site."n"nConclusion: The highest advantage of this cost-benefit approach is to produce different types of molecular weight markers by using an effective and short protocol."n"nKeywords: DNA markers, DNA Ladder, agarose gel electrophoresis, molecular weight.

  17. Quality Content in Distance Education (United States)

    Yildiz, Ezgi Pelin; Isman, Aytekin


    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…

  18. The Psychology of Psychic Distance

    DEFF Research Database (Denmark)

    Håkanson, Lars; Ambos, Björn; Schuster, Anja


    and their theoretical underpinnings assume psychic distances to be symmetric. Building on insights from psychology and sociology, this paper demonstrates how national factors and cognitive processes interact in the formation of asymmetric distance perceptions. The results suggest that exposure to other countries...

  19. The Distance to M51 (United States)

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


    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.

  20. Distance transforms: Academics versus industry

    NARCIS (Netherlands)

    van den Broek, Egon; Schouten, Th.E.

    In image and video analysis, distance transformations (DT) are frequently used. They provide a distance image (DI) of background pixels to the nearest object pixel. DT touches upon the core of many applications; consequently, not only science but also industry has conducted a significant body of

  1. Distance Education and the WWW. (United States)

    Peraya, Daniel


    Examines the evolution of distance education and learning via the use of communication technology. Focuses on distance education as a way of preparing returning adult students to meet demands of the labor market, and reviews uses of the World Wide Web as a communication tool to create electronic classrooms and deliver instructional materials. (JMV)

  2. Distance criterion for hydrogen bond

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. Distance criterion for hydrogen bond. In a D-H ...A contact, the D...A distance must be less than the sum of van der Waals Radii of the D and A atoms, for it to be a hydrogen bond.


    Energy Technology Data Exchange (ETDEWEB)

    McQuinn, Kristen B. W. [University of Texas at Austin, McDonald Observatory, 2515 Speedway, Stop C1400 Austin, TX 78712 (United States); Skillman, Evan D. [Minnesota Institute for Astrophysics, School of Physics and Astronomy, 116 Church Street, SE, University of Minnesota, Minneapolis, MN 55455 (United States); Dolphin, Andrew E. [Raytheon Company, 1151 E. Hermans Road, Tucson, AZ 85756 (United States); Berg, Danielle [Center for Gravitation, Cosmology and Astrophysics, Department of Physics, University of Wisconsin Milwaukee, 1900 East Kenwood Boulevard, Milwaukee, WI 53211 (United States); Kennicutt, Robert, E-mail: [Institute for Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom)


    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.


    Energy Technology Data Exchange (ETDEWEB)

    McQuinn, Kristen B. W. [University of Texas at Austin, McDonald Observatory, 2515 Speedway, Stop C1400 Austin, TX 78712 (United States); Skillman, Evan D. [Minnesota Institute for Astrophysics, School of Physics and Astronomy, 116 Church Street, S.E., University of Minnesota, Minneapolis, MN 55455 (United States); Dolphin, Andrew E. [Raytheon Company, 1151 E. Hermans Road, Tucson, AZ 85756 (United States); Berg, Danielle [Center for Gravitation, Cosmology and Astrophysics, Department of Physics, University of Wisconsin Milwaukee, 1900 East Kenwood Boulevard, Milwaukee, WI 53211 (United States); Kennicutt, Robert, E-mail: [Institute for Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom)


    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.

  5. Virtual Bioinformatics Distance Learning Suite (United States)

    Tolvanen, Martti; Vihinen, Mauno


    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…

  6. Hierarchical traits distances explain grassland Fabaceae species’ ecological niches distances

    Directory of Open Access Journals (Sweden)

    Florian eFort


    Full Text Available 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.

  7. A decision ladder analysis of eco-driving: the first step towards fuel-efficient driving behaviour. (United States)

    McIlroy, Rich C; Stanton, Neville A


    This paper provides a decision ladder analysis of eco-driving, and a discussion of the resultant models in terms of the skills, rules and knowledge taxonomy of human behaviour and how this can inform the design of an in-vehicle, eco-driving support system. In order to understand the types of behaviours that characterise fuel-efficient driving, a review was conducted of the academic literature and of more publicly available resources, such as governmental, car manufacturers' and specific eco-driving organisations' websites. The review identified four largely distinct driving activities that play a central role in the use of fuel in the private road vehicle. A focus group involving four researchers in the transport ergonomics field, followed by a series of five interviews with eco-driving experts, served to validate, supplement and further specify the models. Practitioner Summary: This paper presents a decision ladder analysis of eco-driving. A four-member focus group and five interviews with eco-driving experts were conducted; the resultant models are discussed in terms of supporting fuel-efficient driving behaviours in the novice eco-driver through their potential to inform the design of an in-vehicle eco-driving support system.

  8. Conjugation Length Effect on TPA-Based Optical Limiting Performance of a Series of Ladder-Type Chromophores

    Directory of Open Access Journals (Sweden)

    Yujin Zhang


    Full Text Available Nonlinear optical properties of a series of newly-synthesized ladder-type chromophores containing oligo-p-phenylene moiety with different π-conjugated lengths were theoretically studied by numerically solving the rate equations and the field intensity equation with an iterative predictor-corrector finite-difference time-domain technique. Ab initio calculation results show that the compounds can be described by the three-level model. Based on the two-photon absorption mechanism, highly efficient optical limiting performances are demonstrated in the chromophores, which strongly depend on the π-conjugated length of the molecule. Special attention has been paid to the dynamical two-photon absorption, indicating that the parameter of the medium can affect the dynamical two-photon absorption cross section. Our numerical results agree well with the experimental measurements. It reveals that the increase in the π-conjugated length of ladder-type oligo-p-phenylene for these chromophores leads to enhanced nonlinear optical absorption. The results also provide a method to modulate the optical limiting and dynamical two-photon absorption of the compounds by changing the molecular density and thickness of the absorber.

  9. Hood River and Pelton Ladder Evaluation Studies, Annual Report 2000-2001.

    Energy Technology Data Exchange (ETDEWEB)

    Olsen, Erik


    The Bonneville Power Administration (BPA) funded the development of two master plans which outline the rationale, and general approach, for implementing a defined group of projects that are an integral part of a comprehensive watershed goal to 'Protect, enhance and restore wild and natural populations of anadromous and resident fish within the Hood River Subbasin'. The Hood River Production Master Plan and the Pelton Ladder Master Plan were completed in 1991 and subsequently approved by the Northwest Power Planning Council in 1992. Action items identified in the two master plans, as well as in a later document entitled 'Hood River/Pelton Ladder Master Agreement' (ODFW and CTWSRO Undated), are designed to achieve two biological fish objectives: (1) to increase production of wild summer and winter steelhead (Oncorhynchus mykiss) to levels commensurate with the subbasins current carrying capacity and (2) re-establishing a self-sustaining population of spring chinook salmon (Oncorhynchus tshawytscha). Numerical fish objectives for subbasin escapement, spawner escapement, and subbasin harvest are defined for each of these species in Coccoli (2000). Several projects are presently funded by the BPA to achieve the Hood River subbasin's numerical fish objectives for summer and winter steelhead and spring chinook salmon. They include BPA project numbers 1998-021-00 (Hood River Fish Habitat), 1998-053-03 (Hood River Production Program - CTWSRO: M&E), 1998-053-07 (Parkdale Fish Facility), 1998-053-08 (Powerdale/Oak Springs O&M), and 1998-053-12 (Hood River Steelhead Genetics Study). Collectively, they are implemented under the umbrella of what has come to be defined as the Hood River Production Program (HRPP). The HRPP is jointly implemented by the Oregon Department of Fish and Wildlife (ODFW) and The Confederated Tribes of the Warm Springs Reservation of Oregon (CTWSRO). Strategies for achieving the HRPP's biological fish objectives for the Hood

  10. Approximating Tree Edit Distance through String Edit Distance


    Akutsu, Tatsuya; Fukagawa, Daiji; Takasu, Atsuhiro


    We present an algorithm to approximate edit distance between two ordered and rooted trees of bounded degree. In this algorithm, each input tree is transformed into a string by computing the Euler string, where labels of some edges in the input trees are modified so that structures of small subtrees are reflected to the labels. We show that the edit distance between trees is at least 1/6 and at most O(n 3/4) of the edit distance between the transformed strings, where n is the maximum size of t...

  11. Prenatal Anogenital Distance Is Shorter in Fetuses With Hypospadias. (United States)

    Gilboa, Yinon; Perlman, Sharon; Kivilevitch, Zvi; Messing, Baruch; Achiron, Reuven


    Recent research provides evidence that anogenital distance may serve as a novel metric to assess reproductive potential in men. In children, a shorter anogenital distance was linked with cryptorchidism, hypospadias, and micropenis. Scarce data exist in the literature regarding anogenital distance measurement in the fetus. The aim of our study was to assess whether intrauterine measurement of fetal anogenital distance could assist in the differential diagnosis of male genital anomalies. Anogenital distance was prospectively measured in all cases referred for suspected isolated abnormal male genitalia. Final diagnoses, confirmed by a pediatric urologist, were compared with anogenital distance prenatal measurements. Fifty-two cases were referred for evaluation because of suspected male external genital malformation during a 12-month period. Cases with normal-appearing genitalia, associated major malformations, and early severe fetal growth restriction were excluded from the study. Postnatal examination revealed 14 cases of hypospadias in varying severity and 8 cases of a buried penis. All fetuses with hypospadias had an anogenital distance measurement below the fifth percentile. Statistical analysis revealed a significant difference between the normal mean anogenital distance for gestational age versus those with hypospadias (mean ± SD, 16.90 ± 4.08 and 11.68 ± 3.31 mm, respectively; P = .001). No significant difference was found between the normal mean anogenital distance for gestational age versus those with a buried penis (18.85 ± 2.76 and 19.46 ± 3.41 mm; P = .700). Fetuses with hypospadias have a statistically significant shorter anogenital distance compared with the general population. Therefore, anogenital distance may serve as a complementary objective sonographic parameter in the prenatal assessment and counseling of male external genital anomalies. © 2016 by the American Institute of Ultrasound in Medicine.

  12. Introverts, Extroverts, and Achievement in a Distance Learning Environment (United States)

    Offir, Baruch; Bezalel, Rachel; Barth, Ingrid


    Although difficulties that characterize distance learning (DL) clearly have differential effects on different learners, links between barrier research and individual differences remain relatively unexplored. This study examined the relationship between cognitive style, based on Jung's (1971) theory, and achievement levels among 77 university…

  13. Tracking frequency laser distance gauge

    International Nuclear Information System (INIS)

    Phillips, J.D.; Reasenberg, R.D.


    Advanced astronomical missions with greatly enhanced resolution and physics missions of unprecedented accuracy will require laser distance gauges of substantially improved performance. We describe a laser gauge, based on Pound-Drever-Hall locking, in which the optical frequency is adjusted to maintain an interferometer's null condition. This technique has been demonstrated with pm performance. Automatic fringe hopping allows it to track arbitrary distance changes. The instrument is intrinsically free of the nm-scale cyclic bias present in traditional (heterodyne) high-precision laser gauges. The output is a radio frequency, readily measured to sufficient accuracy. The laser gauge has operated in a resonant cavity, which improves precision, can suppress the effects of misalignments, and makes possible precise automatic alignment. The measurement of absolute distance requires little or no additional hardware, and has also been demonstrated. The proof-of-concept version, based on a stabilized HeNe laser and operating on a 0.5 m path, has achieved 10 pm precision with 0.1 s integration time, and 0.1 mm absolute distance accuracy. This version has also followed substantial distance changes as fast as 16 mm/s. We show that, if the precision in optical frequency is a fixed fraction of the linewidth, both incremental and absolute distance precision are independent of the distance measured. We discuss systematic error sources, and present plans for a new version of the gauge based on semiconductor lasers and fiber-coupled components

  14. Precision Distances with the Tip of the Red Giant Branch Method (United States)

    Beaton, Rachael Lynn; Carnegie-Chicago Hubble Program Team


    The Carnegie-Chicago Hubble Program aims to construct a distance ladder that utilizes old stellar populations in the outskirts of galaxies to produce a high precision measurement of the Hubble Constant that is independent of Cepheids. The CCHP uses the tip of the red giant branch (TRGB) method, which is a statistical measurement technique that utilizes the termination of the red giant branch. Two innovations combine to make the TRGB a competitive route to the Hubble Constant (i) the large-scale measurement of trigonometric parallax by the Gaia mission and (ii) the development of both precise and accurate means of determining the TRGB in both nearby (~1 Mpc) and distant (~20 Mpc) galaxies. Here I will summarize our progress in developing these standardized techniques, focusing on both our edge-detection algorithm and our field selection strategy. Using these methods, the CCHP has determined equally precise (~2%) distances to galaxies in the Local Group (< 1 Mpc) and across the Local Volume (< 20 Mpc). The TRGB is, thus, an incredibly powerful and straightforward means to determine distances to galaxies of any Hubble Type and, thus, has enormous potential for putting any number of astrophyiscal phenomena on absolute units.

  15. Language distance and tree reconstruction

    International Nuclear Information System (INIS)

    Petroni, Filippo; Serva, Maurizio


    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

  16. Language distance and tree reconstruction (United States)

    Petroni, Filippo; Serva, Maurizio


    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.

  17. Stringy Gravity: Solving the Dark Problems at `short' distance (United States)

    Park, Jeong-Hyuck


    Dictated by Symmetry Principle, string theory predicts not General Relativity but its own gravity which assumes the entire closed string massless sector to be geometric and thus gravitational. In terms of R/(MG), i.e. the dimensionless radial variable normalized by mass, Stringy Gravity agrees with General Relativity toward infinity, but modifies it at short distance. At far short distance, gravitational force can be even repulsive. These may solve the dark matter and energy problems, as they arise essentially from small R/(MG) observations: long distance divided by much heavier mass. We address the pertinent differential geometry for Stringy Gravity, stringy Equivalence Principle, stringy geodesics and the minimal coupling to the Standard Model. We highlight the notion of `doubled-yet-gauged' coordinate system, in which a gauge orbit corresponds to a single physical point and proper distance is defined between two gauge orbits by a path integral.

  18. Designing Instruction for Distance Learning

    National Research Council Canada - National Science Library

    Main, Robert


    ... pressure on the training and education fields to meet the demand. Emerging communication technologies have enabled alternative methods for delivering training via distance learning that are being rapidly adopted by academia and industry...

  19. Interactive Multimedia Distance Learning (IMDL)

    National Research Council Canada - National Science Library

    Crhistinaz, Daniel


    .... One avenue of investigation has been to evaluate emerging computer and network technologies to determine if training can be delivered at a distance more efficiently than traditional classroom training...


    Directory of Open Access Journals (Sweden)

    Wolfram LAASER


    Full Text Available ABSTRACT According to Gartner a certain hype of e-Learning was followed by a downturn but eLearning will continue to be an important factor in learning scenarios. However the economic viability of e-learning projects will be questioned with more scrutiny than in earlier periods. Therefore it seems to be a good opportunity to see what can be learned from past experience in costing distance learning projects and what aspects are added by current attempts to measure economic efficiency. After reviewing early research about costing distance learning some more recent approaches will be discussed, such as eLearning ROI-calculators and the concept of total cost of ownership. Furthermore some microeconomic effects referring to localization of distance learning courses are outlined. Finally several unsolved issues in costing distance education are summarized.

  1. Academy Distance Learning Tools (IRIS) - (United States)

    Department of Transportation — IRIS is a suite of front-end web applications utilizing a centralized back-end Oracle database. The system fully supports the FAA Academy's Distance Learning Program...

  2. Distance labeling schemes for trees

    DEFF Research Database (Denmark)

    Alstrup, Stephen; Gørtz, Inge Li; Bistrup Halvorsen, Esben


    We consider distance labeling schemes for trees: given a tree with n nodes, label the nodes with binary strings such that, given the labels of any two nodes, one can determine, by looking only at the labels, the distance in the tree between the two nodes. A lower bound by Gavoille et al. [Gavoille...... variants such as, for example, small distances in trees [Alstrup et al., SODA, 2003]. We improve the known upper and lower bounds of exact distance labeling by showing that 1/4 log2(n) bits are needed and that 1/2 log2(n) bits are sufficient. We also give (1 + ε)-stretch labeling schemes using Theta...

  3. Distance Education in Technological Age

    Directory of Open Access Journals (Sweden)

    R .C. SHARMA


    Full Text Available Distance Education in Technological AgeRomesh Verma (Editor, New Delhi: Anmol Publications, 2005, ISBN 81-261-2210-2, pp. 419 Reviewed by R C SHARMARegional DirectorIndira Gandhi National Open University-INDIA The advancements in information and communication technologies have brought significant changes in the way the open and distance learning are provided to the learners. The impact of such changes is quite visible in both developed and developing countries. Switching over to online mode, joining hands with private initiatives and making a presence in foreign waters, are some of the hallmarks of the open and distance education (ODE institutions in developing countries. The compilation of twenty six essays on themes as applicable to ODE has resulted in the book, “Distance Education in Technological Age”. These essays follow a progressive style of narration, starting from describing conceptual framework of distance education, how the distance education was emerged on the global scene and in India, and then goes on to discuss emergence of online distance education and research aspects in ODE. The initial four chapters provide a detailed account of historical development and growth of distance education in India and State Open University and National Open University Model in India . Student support services are pivot to any distance education and much of its success depends on how well the support services are provided. These are discussed from national and international perspective. The issues of collaborative learning, learning on demand, life long learning, learning-unlearning and re-learning model and strategic alliances have also given due space by the authors. An assortment of technologies like communication technology, domestic technology, information technology, mass media and entertainment technology, media technology and educational technology give an idea of how these technologies are being adopted in the open universities. The study

  4. Designing Instruction for Distance Learning

    National Research Council Canada - National Science Library

    Main, Robert


    .... While distance learning has been demonstrated to be an effective and efficient tool for increased access it also requires greater emphasis on instructional design and instructor training to obtain satisfactory results...

  5. Real-space localization and quantification of hole distribution in chain-ladder Sr3Ca11Cu24O41 superconductor. (United States)

    Bugnet, Matthieu; Löffler, Stefan; Hawthorn, David; Dabkowska, Hanna A; Luke, Graeme M; Schattschneider, Peter; Sawatzky, George A; Radtke, Guillaume; Botton, Gianluigi A


    Understanding the physical properties of the chain-ladder Sr3Ca11Cu24O41 hole-doped superconductor has been precluded by the unknown hole distribution among chains and ladders. We use electron energy-loss spectrometry (EELS) in a scanning transmission electron microscope (STEM) at atomic resolution to directly separate the contributions of chains and ladders and to unravel the hole distribution from the atomic scale variations of the O-K near-edge structures. The experimental data unambiguously demonstrate that most of the holes lie within the chain layers. A quantitative interpretation supported by inelastic scattering calculations shows that about two holes are located in the ladders, and about four holes in the chains, shedding light on the electronic structure of Sr3Ca11Cu24O41. Combined atomic resolution STEM-EELS and inelastic scattering calculations is demonstrated as a powerful approach toward a quantitative understanding of the electronic structure of cuprate superconductors, offering new possibilities for elucidating their physical properties.

  6. A Study to Identify Career-Ladder Positions, Records Management Tasks, and Educational Curricula for Entry-Level, Intermediate and Advanced Records Management Positions. (United States)

    Wallace, Patricia Erwin


    A study was made of career-ladder positions that are available to students studying records management at various education levels to determine the tasks that are performed by records management personnel at various employment levels and to determine the tasks that should be included in records management courses. (CT)

  7. Up and down the sanitation ladder: Harmonizing the treatment and multiple-barrier perspectives on risk reduction in wastewater irrigated agriculture

    DEFF Research Database (Denmark)

    Keraita, Bernard; Drechsel, P.; Konradsen, Flemming


    perspective has strengths and mitations. Rather than being opposing philosophies, they both support health risk reduction but in different ways depending on the level of the country in the sanitation ladder. Since each perspective has limitations, the recommendation is to capitalize on their strengths...

  8. CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES: Gap Caused by Strong Pairing in the Ladder Model of DNA Molecules (United States)

    Hu, Dong-Sheng; Zhu, Chen-Ping; Zhang, Long-Qiang; He, Da-Ren; Wang, Bing-Hong


    By directly diagonalizing the Hamiltonian of the ladder model of deoxyribonucleic acid (DNA) molecules, the density of states is obtained. It is found that DNA behaves as a conductor when the interchain hopping is smaller than twice the intrachain one, otherwise, DNA behaves as a semiconductor.

  9. Resolving distance ambiguities towards 6.7 GHz methanol masers (United States)

    Pandian, J. D.; Momjian, E.; Goldsmith, P. F.


    Context: Distances to most star forming regions are determined using kinematics, through the assumption that the observed radial velocity arises from the motion of the source with respect to the Sun resulting from the differential rotation of Galaxy. The primary challenge associated with the application of this technique in the inner Galaxy is the kinematic distance ambiguity. Aims: In this work, we aim to resolve the kinematic distance ambiguity towards a sample of 6.7 GHz methanol masers, which are signposts of the early stages of massive star formation. Methods: We measured 21 cm H I absorption spectra using the Very Large Array in C and CnB configurations. A comparison of the maximum velocity of H I absorption with the source velocity and tangent point velocity was used to resolve the kinematic distance ambiguity. Results: We resolved the distance ambiguity towards 41 sources. Distance determinations that are in conflict with previous measurements are discussed. The NE2001 spiral arm model is broadly consistent with the locations of the star forming complexes. We find that the use of vertical scale height arguments to resolve the distance ambiguity can lead to erroneous classifications for a significant fraction of sources.

  10. The effect of ladder-climbing exercise on atrophy/hypertrophy-related myokine expression in middle-aged male Wistar rats. (United States)

    Jung, Suryun; Ahn, Nayoung; Kim, Sanghyun; Byun, Jayoung; Joo, Youngsik; Kim, Sungwook; Jung, Yeunho; Park, Solee; Hwang, Ilseon; Kim, Kijin


    We investigated the change in myokine expression related to hypertrophy (IL-4, IL-6, IL-10) and atrophy (TNF-α, NFκB, IL-1β) in middle-aged rats after resistance exercise with ladder climbing. 50- and 10-week-old male Wistar rats were randomly assigned to two groups: the sedentary and exercise groups. The exercise groups underwent a ladder-climbing exercise for 8 weeks. While the tibialis anterior muscle mass in the young group significantly increased after the ladder-climbing exercise, the middle-aged group did not show any changes after undergoing the same exercise. To understand the molecular mechanism causing this difference, we analyzed the change in hypertrophy- and atrophy-related myokine levels from the tibialis anterior muscle. After 8 weeks of ladder-climbing exercise, the IL-4 and IL-10 protein levels did not change. However, the IL-6 level significantly increased after exercise training, but the amount of increase in the young training group was higher than in the middle-aged training group. IL-1β and TNF-α as well as NFκB protein levels were significantly higher in the middle-aged group than in the young group. Except for TNF-α, exercise training did not affect IL-1β and NFκB protein levels. The TNF-α level significantly decreased in the middle-aged exercise training group. AMPK and PGC-1α levels also significantly increased after exercise training, but there was no difference between age-related groups. Therefore, 8-week high-intensity exercise training using ladder climbing downregulates the skeletal muscle production of myokine involved in atrophy and upregulates hypertrophic myokine. However, the extent of these responses was lower in the middle-aged than young group.

  11. Harmonic analysis approach to the 'TunneLadder' - A modified Karp circuit for millimeter-wave TWTA's (United States)

    Kosmahl, H. G.; Palmer, R. W.


    A field approach to the summed harmonic analysis of the TunneLadder structure, or modified forward-wave Karp circuit, is developed by combining TM(01) and TE(11) modes. Results suggest the suitability of this structure as a high-impedance, about 1-% bandwidth circuit, millimeter-wave forward-wave-type amplifier that is voltage tunable over about a 5-% frequency range and has excellent power handling ability. Theory gives good agreement with experimental results obtained by Karp in omega-beta dispersion and predicts qualitatively the appearances of the antisymmetric mode discussed and of the so called Hightron mode that was discussed earlier in White, Enderby and Birdsall (1964), and Enderby (1964), in addition to the desired symmetric mode.

  12. Alkylated selenophene-based ladder-type monomers via a facile route for high performance thin-film transistor applications

    KAUST Repository

    Fei, Zhuping


    We report the synthesis of two new selenophene containing ladder-type monomers, cyclopentadiselenophene (CDS) and indacenodiselenophene (IDSe), via a twofold and fourfold Pd catalyzed coupling with a 1,1-diborylmethane derivative. Co-polymers with benzothiadiazole (BT) were prepared in high yield by Suzuki polymerization to afford co-polymers which exhibited excellent solubility in a range of non-chlorinated solvents. The CDS co-polymer exhibited a band gap of just 1.18 eV, which is amongst the lowest reported for donor-acceptor polymers. Thin-film transistors were fabricated using environmentally benign, non-chlorinated solvents with the CDS and IDSe co-polymers exhibiting hole mobility up to 0.15 and 6.4 cm2 /Vs, respectively. This high performance was achieved without the undesirable peak in mobility often observed at low gate voltages due to parasitic contact resistance.

  13. Tunable photonic band gaps and optical nonreciprocity by an RF-driving ladder-type system in moving optical lattice (United States)

    Ba, Nuo; Zhong, Xin; Wang, Lei; Fei, Jin-You; Zhang, Yan; Bao, Qian-Qian; Xiao, Li


    We investigate photonic transport properties of the 1D moving optical lattices filled with vast cold atoms driven into a four-level ladder-type system and obtain dynamically controlled photonic bandgaps and optical nonreciprocity. It is found that the two obvious optical nonreciprocity can be generated at two well-developed photonic bandgaps based on double dark states in the presence of a radio-frequency field. However, when the radio-frequency field is absence, the only one induced photonic bandgaps with distinguishing optical nonreciprocity can be opened up via single dark state. Dynamic control of the induced photonic bandgaps and optical nonreciprocity could be exploited to achieve all-optical diodes and routing for quantum information networks.

  14. The ladder operator normal ordering problem for quantum confined systems and the generalization of the Stirling and Bell numbers

    International Nuclear Information System (INIS)

    Aleixo, A N F; Balantekin, A B


    We solve the normal ordering problem for the ladder operators B-hat + and B-hat - for strings in the form (B-hat + r B-hat - s ) n for supersymmetric and shape-invariant potential systems, with r, s and n positive integers. We provide exact and explicit expressions for their normal form N{(B-hat + r B-hat - s ) n }, where N{...} all B-hat - are at the right side, and find that the solution involves an expansion coefficients sequence which, for r, s > 1, corresponds to the generalization, for any shape-invariant potential system, of the classical Stirling and Bell numbers. We show that these numbers are obtained for families of polynomials generated with parameters related to the forms of the supersymmetric partner potentials. We apply the general formalism to Poeschl-Teller, Morse, Scarf and self-similar potential systems.

  15. The cooling of printed circuit board mounted components using copper ladder heat conduction to a cold wall (United States)

    Dale, I. C.


    A series of experimental tests, designed to investigate the cooling of printed circuit board (PCB) mounted dual-in-line (DIL) components within an avionic box using the copper ladder/cold wall technique is described. Areas of investigation include avionic box orientation, side wall conduction, top plate finning, mixed air-wash, avionic power reduction, cooling air temperature reduction, cooling air mass flow rate reduction, cold wall heat pick-up and avionic box insulation. Results were obtained from thermocouple temperature measurements. The use of an aluminum alloy interplate to cool two adjacent PCBs is discussed. Results in graphic form are included together with a list of conclusions on the effects of all the major parameters considered.

  16. Hood River production program monitoring and evaluation. Report A: Hood River and Pelton Ladder evaluation studies. Annual report for 1996

    International Nuclear Information System (INIS)

    Olsen, E.A.; French, R.A.


    In 1992, the Northwest Power Planning Council approved the Hood River and Pelton Ladder master plans within the framework of the Columbia River Basin Fish and Wildlife Program. The master plans define an approach for implementing a hatchery supplementation program in the Hood River subbasin. The hatchery program, as defined in the master plans, is called the Hood River Production Program (HRPP). The HRPP will be implemented at a reduced hatchery production level until (1) the construction of all proposed hatchery facilities has been completed and (2) numbers of returning wild jack and adult fish are sufficient to meet broodstock collection goals. It is anticipated that construction on the hatchery production facilities will be completed by the spring of 1998. The HRPP is jointly implemented by the Oregon Department of Fish and Wildlife (ODFW) and the Confederated Tribes of the Warm Springs (CTWS) Reservation

  17. Counting distance: Effects of egocentric distance on numerical perception.

    Directory of Open Access Journals (Sweden)

    Nurit Gronau

    Full Text Available Numerical value is long known to be associated with a variety of magnitude representations, such as size, time and space. The present study focused on the interactive relations of numerical magnitude with a spatial factor which is dominant in everyday vision and is often overlooked, namely, egocentric distance, or depth. We hypothesized that digits denoting large magnitudes are associated with large perceived distances, and vice versa. While the relations of numerical value and size have been long documented, effects of egocentric distance on numeral perception have been scarcely investigated, presumably due to the difficulty to disentangle size and depth factors within three-dimensional visual displays. The current study aimed to assess the potential linkage between egocentric distance and number magnitude, while neutralizing any perceived and/or physical size parameters of target digits. In Experiment 1, participants conducted a numeral size-classification task ('bigger or smaller than 5', to which they responded with a near-to-body or a far-from-body key. Results revealed shorter responses for small than for large numbers when responded with a key positioned close to the body, and for large than small numbers when responded with a key positioned far from the body (regardless of hand-key mapping. Experiment 2 used verbal stimuli denoting near/remote concepts as irrelevant primes to target digits, further demonstrating a priming effect of conceived distance on numerical value processing. Collectively, our results suggest that distance magnitudes are associatively linked to numerical magnitudes and may affect digit processing independently of the effects of visual size.

  18. First functionality tests of a 64 × 64 pixel DSSC sensor module connected to the complete ladder readout (United States)

    Donato, M.; Hansen, K.; Kalavakuru, P.; Kirchgessner, M.; Kuster, M.; Porro, M.; Reckleben, C.; Turcato, M.


    The European X-ray Free Electron Laser (XFEL.EU) will provide every 0.1 s a train of 2700 spatially coherent ultrashort X-ray pulses at 4.5 MHz repetition rate. The Small Quantum Systems (SQS) instrument and the Spectroscopy and Coherent Scattering instrument (SCS) operate with soft X-rays between 0.5 keV-6 keV. The DEPFET Sensor with Signal Compression (DSSC) detector is being developed to meet the requirements set by these two XFEL.EU instruments. The DSSC imager is a 1 mega-pixel camera able to store up to 800 single-pulse images per train. The so-called ladder is the basic unit of the DSSC detector. It is the single unit out of sixteen identical-units composing the DSSC-megapixel camera, containing all representative electronic components of the full-size system and allows testing the full electronic chain. Each DSSC ladder has a focal plane sensor with 128× 512 pixels. The read-out ASIC provides full-parallel readout of the sensor pixels. Every read-out channel contains an amplifier and an analog filter, an up-to 9 bit ADC and the digital memory. The ASIC amplifier have a double front-end to allow one to use either DEPFET sensors or Mini-SDD sensors. In the first case, the signal compression is a characteristic intrinsic of the sensor; in the second case, the compression is implemented at the first amplification stage. The goal of signal compression is to meet the requirement of single-photon detection capability and wide dynamic range. We present the first results of measurements obtained using a 64× 64 pixel DEPFET sensor attached to the full final electronic and data-acquisition chain.

  19. Detection of chronic sensorimotor impairments in the ladder rung walking task in rats with endothelin-1-induced mild focal ischemia. (United States)

    Riek-Burchardt, Monika; Henrich-Noack, Petra; Metz, Gerlinde A; Reymann, Klaus G


    A comprehensive evaluation of the effects of neuroprotection, neurogenesis, and compensatory mechanisms on the outcome of ischemic insults requires assessment of morphological and functional parameters. Behavioural tests are essential when recording performance throughout the time course of an experiment and the results bear predictive value in preclinical animal models. The goal of this study was to establish a behavioural test procedure for a model of transient focal ischemia induced by injection of endothelin-1 (eMCAO) that results in relatively mild behavioural deficits. The test protocol used in the present study allows evaluation of quantitative and qualitative impairments in skilled motor performance and is sensitive to detect chronic deficits at chronic post-ischemic time intervals. The ladder rung walking task [J. Neurosci. Methods 115 (2002) 169] is a motor test that assesses skilled walking and measures both forelimb and hindlimb placing, stepping and inter-limb co-ordination. In this study we tested the effect of two different technical variants of endothelin-1 application on infarct volume and motor skills (1) application via pre-implanted guiding cannula in awake animals and (2) via direct injection under halothane anaesthesia. We showed that the ladder rung walking task is sensitive in the assessment of loss of fine motor function after induction of relatively small lesions. In animals with implanted cannulas we found a smaller infarct area and an increase in placement errors prior to ischemia animals with eMCAO under anaesthesia showed a long lasting impairment of the contralateral forelimb up to 4 weeks post-eMCAO.

  20. Algorithmic implementation of particle-particle ladder diagram approximation to study strongly-correlated metals and semiconductors (United States)

    Prayogi, A.; Majidi, M. A.


    In condensed-matter physics, strongly-correlated systems refer to materials that exhibit variety of fascinating properties and ordered phases, depending on temperature, doping, and other factors. Such unique properties most notably arise due to strong electron-electron interactions, and in some cases due to interactions involving other quasiparticles as well. Electronic correlation effects are non-trivial that one may need a sufficiently accurate approximation technique with quite heavy computation, such as Quantum Monte-Carlo, in order to capture particular material properties arising from such effects. Meanwhile, less accurate techniques may come with lower numerical cost, but the ability to capture particular properties may highly depend on the choice of approximation. Among the many-body techniques derivable from Feynman diagrams, we aim to formulate algorithmic implementation of the Ladder Diagram approximation to capture the effects of electron-electron interactions. We wish to investigate how these correlation effects influence the temperature-dependent properties of strongly-correlated metals and semiconductors. As we are interested to study the temperature-dependent properties of the system, the Ladder diagram method needs to be applied in Matsubara frequency domain to obtain the self-consistent self-energy. However, at the end we would also need to compute the dynamical properties like density of states (DOS) and optical conductivity that are defined in the real frequency domain. For this purpose, we need to perform the analytic continuation procedure. At the end of this study, we will test the technique by observing the occurrence of metal-insulator transition in strongly-correlated metals, and renormalization of the band gap in strongly-correlated semiconductors.

  1. Distance sampling methods and applications

    CERN Document Server

    Buckland, S T; Marques, T A; Oedekoven, C S


    In this book, the authors cover the basic methods and advances within distance sampling that are most valuable to practitioners and in ecology more broadly. This is the fourth book dedicated to distance sampling. In the decade since the last book published, there have been a number of new developments. The intervening years have also shown which advances are of most use. This self-contained book covers topics from the previous publications, while also including recent developments in method, software and application. Distance sampling refers to a suite of methods, including line and point transect sampling, in which animal density or abundance is estimated from a sample of distances to detected individuals. The book illustrates these methods through case studies; data sets and computer code are supplied to readers through the book’s accompanying website.  Some of the case studies use the software Distance, while others use R code. The book is in three parts.  The first part addresses basic methods, the ...

  2. Computing Distances between Probabilistic Automata

    Directory of Open Access Journals (Sweden)

    Mathieu Tracol


    Full Text Available We present relaxed notions of simulation and bisimulation on Probabilistic Automata (PA, that allow some error epsilon. When epsilon is zero we retrieve the usual notions of bisimulation and simulation on PAs. We give logical characterisations of these notions by choosing suitable logics which differ from the elementary ones, L with negation and L without negation, by the modal operator. Using flow networks, we show how to compute the relations in PTIME. This allows the definition of an efficiently computable non-discounted distance between the states of a PA. A natural modification of this distance is introduced, to obtain a discounted distance, which weakens the influence of long term transitions. We compare our notions of distance to others previously defined and illustrate our approach on various examples. We also show that our distance is not expansive with respect to process algebra operators. Although L without negation is a suitable logic to characterise epsilon-(bisimulation on deterministic PAs, it is not for general PAs; interestingly, we prove that it does characterise weaker notions, called a priori epsilon-(bisimulation, which we prove to be NP-difficult to decide.

  3. High accuracy absolute distance metrology (United States)

    Swinkels, Bas L.; Bhattacharya, Nandini; Verlaan, Ad L.; Braat, Joseph J. M.


    One of ESA's future missions is the Darwin Space Interferometer, which aims to detect planets around nearby stars using optical aperture synthesis with free-flying telescopes. Since this involves interfering white (infra-red) light over large distances, the mission is not possible without a complex metrology system that monitors various speeds, distances and angles between the satellites. One of its sub-systems should measure absolute distances with an accuracy of around 70 micrometer over distances up to 250 meter. To enable such measurements, we are investigating a technique called frequency sweeping interferometry, in which a single laser is swept over a large known frequency range. Central to our approach is the use of a very stable, high finesse Fabry-Ṕerot cavity, to which the laser is stabilized at the endpoints of the frequency sweep. We will discuss the optical set-up, the control system that controls the fast sweeping, the calibration and the data analysis. We tested the system using long fibers and achieved a repeatability of 50 micrometers at a distance of 55 meters. We conclude with some recommendations for further improvements and the adaption for use in space.

  4. Pararescue/Recovery Career Ladder, AFSCs 11530, 11550, 11570, 11590, and CEM Code 11500. (United States)



  5. Euclidean distance geometry an introduction

    CERN Document Server

    Liberti, Leo


    This textbook, the first of its kind, presents the fundamentals of distance geometry:  theory, useful methodologies for obtaining solutions, and real world applications. Concise proofs are given and step-by-step algorithms for solving fundamental problems efficiently and precisely are presented in Mathematica®, enabling the reader to experiment with concepts and methods as they are introduced. Descriptive graphics, examples, and problems, accompany the real gems of the text, namely the applications in visualization of graphs, localization of sensor networks, protein conformation from distance data, clock synchronization protocols, robotics, and control of unmanned underwater vehicles, to name several.  Aimed at intermediate undergraduates, beginning graduate students, researchers, and practitioners, the reader with a basic knowledge of linear algebra will gain an understanding of the basic theories of distance geometry and why they work in real life.

  6. Constraint Differentiation

    DEFF Research Database (Denmark)

    Mödersheim, Sebastian Alexander; Basin, David; Viganò, Luca


    We introduce constraint differentiation, a powerful technique for reducing search when model-checking security protocols using constraint-based methods. Constraint differentiation works by eliminating certain kinds of redundancies that arise in the search space when using constraints to represent...... results show that constraint differentiation substantially reduces search and considerably improves the performance of OFMC, enabling its application to a wider class of problems....

  7. Differential manifolds

    CERN Document Server

    Kosinski, Antoni A


    The concepts of differential topology form the center of many mathematical disciplines such as differential geometry and Lie group theory. Differential Manifolds presents to advanced undergraduates and graduate students the systematic study of the topological structure of smooth manifolds. Author Antoni A. Kosinski, Professor Emeritus of Mathematics at Rutgers University, offers an accessible approach to both the h-cobordism theorem and the classification of differential structures on spheres.""How useful it is,"" noted the Bulletin of the American Mathematical Society, ""to have a single, sho

  8. Steiner Distance in Graphs--A Survey


    Mao, Yaping


    For a connected graph $G$ of order at least $2$ and $S\\subseteq V(G)$, the \\emph{Steiner distance} $d_G(S)$ among the vertices of $S$ is the minimum size among all connected subgraphs whose vertex sets contain $S$. In this paper, we summarize the known results on the Steiner distance parameters, including Steiner distance, Steiner diameter, Steiner center, Steiner median, Steiner interval, Steiner distance hereditary graph, Steiner distance stable graph, average Steiner distance, and Steiner ...

  9. Video surveillance using distance maps (United States)

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


    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.

  10. Gesture Interaction at a Distance

    NARCIS (Netherlands)

    Fikkert, F.W.


    The aim of this work is to explore, from a perspective of human behavior, which gestures are suited to control large display surfaces from a short distance away; why that is so; and, equally important, how such an interface can be made a reality. A well-known example of the type of interface that is

  11. Cooperative Distance Learning in Mathematics (United States)

    Guimaraes, Luiz Carlos; Moraes, Thiago Guimaraes; Mattos, Francisco Roberto Pinto


    In this paper we report on two complementary research results. In the first we describe a tool that allows different modes of synchronous distance teaching of mathematics. In the second we report the preliminary results of a pilot study conducted using this tool to teach geometry, both with school students aged 14-15 and with undergraduate…

  12. Adaptive Distance Protection for Microgrids

    DEFF Research Database (Denmark)

    Lin, Hengwei; Guerrero, Josep M.; Quintero, Juan Carlos Vasquez


    is adopted to accelerate the tripping speed of the relays on the weak lines. The protection methodology is tested on a mid-voltage microgrid network in Aalborg, Denmark. The results show that the adaptive distance protection methodology has good selectivity and sensitivity. What is more, this system also has...

  13. Distance Education Technologies in Asia

    International Development Research Centre (IDRC) Digital Library (Canada)

    17 schools ... The use of other Asian DE experiences as basis for planning is a logical move for Mongolia because most Asian countries that are now involved in DE have a .... for distance education in the region, and the pioneering examples these provide for other Asian countries with similar physical and social conditions.

  14. Quality Connection: Going the Distance (United States)

    Jenney, Timothy R.; Roupas, Eva K.


    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…

  15. Designing a Distance Learning Facility. (United States)

    Lambert, Michael P.


    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…

  16. Fish passage post-construction issues: analysis of distribution, attraction and passage efficiency metrics at the Baguari Dam fish ladder to approach the problem

    Directory of Open Access Journals (Sweden)

    Luiz Gustavo Martins da Silva

    Full Text Available Fish passages are considered the oldest management tool used to minimize the impact of blocking fish migratory routes by hydroelectric power plants. However, fish passages are being installed without specific criteria in Brazil, with severe consequences to the conservation of the local fish fauna. Therefore, basic data gathered for fish passages already constructed could contribute to define operational rules, in addition to offer subsidies to decision-making and design of future facilities. Thus, the fish ladder of Baguari Dam was evaluated regarding temporal distribution, attraction, and ascension of the local fish fauna. A total of 20 fish samples were conducted immediately downstream of the dam and inside the fish ladder, from January 2010 to June 2011. Seasonal variation in fish abundance and richness was registered below the dam and inside the passage, with higher number of migratory fish in the reproductive season (Kruskall-Wallis, p = 0.04 and p = 0.05. Furthermore, higher concentration of migratory allochthonous and non-migratory species was registered for the spill bay (Wilcoxon, p = 0.009 and p = 0.006 compared to the tailrace, where the fish ladder entrance is located. This result suggests low efficiency of the attraction system of the mechanism during the reproductive period. Once entering the fish ladder, migratory species apparently ascend the facility due to the similar distribution throughout different stretches. Generally, the results showed that an operational rule for the Baguari Dam fish ladder should consider running the facility only during the reproductive period, unless the objectives of the passage are well defined. The attraction system must be more precisely evaluated, using technologies such as radiotelemetry. Similarly, fish ascension also should be better analyzed to evaluate the time spent to ascend and its influence in the reproductive biology of the species using the ladder. Pit-tag system could be used to

  17. On Markov Earth Mover's Distance. (United States)

    Wei, Jie


    In statistics, pattern recognition and signal processing, it is of utmost importance to have an effective and efficient distance to measure the similarity between two distributions and sequences. In statistics this is referred to as goodness-of-fit problem . Two leading goodness of fit methods are chi-square and Kolmogorov-Smirnov distances. The strictly localized nature of these two measures hinders their practical utilities in patterns and signals where the sample size is usually small. In view of this problem Rubner and colleagues developed the earth mover's distance (EMD) to allow for cross-bin moves in evaluating the distance between two patterns, which find a broad spectrum of applications. EMD-L1 was later proposed to reduce the time complexity of EMD from super-cubic by one order of magnitude by exploiting the special L1 metric. EMD-hat was developed to turn the global EMD to a localized one by discarding long-distance earth movements. In this work, we introduce a Markov EMD (MEMD) by treating the source and destination nodes absolutely symmetrically. In MEMD, like hat-EMD, the earth is only moved locally as dictated by the degree d of neighborhood system. Nodes that cannot be matched locally is handled by dummy source and destination nodes. By use of this localized network structure, a greedy algorithm that is linear to the degree d and number of nodes is then developed to evaluate the MEMD. Empirical studies on the use of MEMD on deterministic and statistical synthetic sequences and SIFT-based image retrieval suggested encouraging performances.

  18. Differential games. (United States)

    Varaiya, P. P.


    General discussion of the theory of differential games with two players and zero sum. Games starting at a fixed initial state and ending at a fixed final time are analyzed. Strategies for the games are defined. The existence of saddle values and saddle points is considered. A stochastic version of a differential game is used to examine the synthesis problem.

  19. A Streaming Distance Transform Algorithm for Neighborhood-Sequence Distances

    Directory of Open Access Journals (Sweden)

    Nicolas Normand


    Full Text Available We describe an algorithm that computes a “translated” 2D Neighborhood-Sequence Distance Transform (DT using a look up table approach. It requires a single raster scan of the input image and produces one line of output for every line of input. The neighborhood sequence is specified either by providing one period of some integer periodic sequence or by providing the rate of appearance of neighborhoods. The full algorithm optionally derives the regular (centered DT from the “translated” DT, providing the result image on-the-fly, with a minimal delay, before the input image is fully processed. Its efficiency can benefit all applications that use neighborhood- sequence distances, particularly when pipelined processing architectures are involved, or when the size of objects in the source image is limited.

  20. Helicopter Mechanic Career Ladder (AFSC 431X0C/D). (United States)


    DPAT 3 3 HQ MAC/TTGT 1 1 HQ TAC/DPATJ 3 3 HQ TAC/TTGT 1 1 HQ USAF/LEYW 1 1 HQ USAF/ MPPT 1 1 HQ USAFE/DPAT 3 3 HQ USAFE/TTGT 1 1 HQ USMC (CODE TPI) 1...Quality Control Inspectors (GRP031, N=23) C. Helicopter Maintenance and Support NCOICs (GRPO39, N=55) D. Maintenance Control Specialists (GRP035, or unit on-the-job train- ing (OJT) programs. Quality Control Inspectors are differentiated by tasks related to the development, implementation, and

  1. Identification of repeat sequence heterogeneity at the polymorphic short tandem repeat locus HUMTH01[AATG]n and reassignment of alleles in population analysis by using a locus-specific allelic ladder.


    Puers, C; Hammond, H A; Jin, L; Caskey, C T; Schumm, J W


    An allelic ladder containing amplified sequences of seven alleles of the polymorphic human tyrosine hydroxylase locus, HUMTH01, was constructed and employed as a standard marker. Sequence analysis of each ladder component indicates that fragments differ by integral multiples of the AATG core repeat sequence characteristic of this locus. Individual alleles are designated "5" through "11," according to the number of complete reiterations of the core repeat contained within them. Comparison of t...

  2. Estimation of Structure-Borne Noise Reduction Effect of Steel Railway Bridge Equipped with Floating Ladder Track and Floating Reinforced-Concrete Deck (United States)

    Watanabe, Tsutomu; Sogabe, Masamichi; Asanuma, Kiyoshi; Wakui, Hajime

    A number of steel railway bridges have been constructed in Japan. Thin steel members used for the bridges easily tend to vibrate and generate structure-borne noise. Accordingly, the number of constructions of steel railway bridges tends to decrease in the urban areas from a viewpoint of environmental preservation. Then, as a countermeasure against structure-borne noise generated from steel railway bridges, we have developed a new type of the steel railway bridge equipped with a floating-ladder track and a floating reinforced-concrete (RC) deck. As a result of train-running experiment, it became apparent that the new steel railway bridge installed by double floating system has reduced a vibration velocity level by 10.5 dB(A) at main girder web as compared with a steel railway bridge installed by directly fastened track. This reduction effect was achieved by the ladder track and RC deck supported by resilient materials.

  3. The intractability of computing the Hamming distance

    NARCIS (Netherlands)

    Manthey, Bodo; Reischuk, Rüdiger


    Given a string x and a language L, the Hamming distance of x to L is the minimum Hamming distance of x to any string in L. The edit distance of a string to a language is analogously defined. First, we prove that there is a language in $AC^0$ such that both Hamming and edit distance to this language

  4. Moral distance in dictator games

    Directory of Open Access Journals (Sweden)

    Fernando Aguiar


    Full Text Available We perform an experimental investigation using a dictator game in which individuals must make a moral decision --- to give or not to give an amount of money to poor people in the Third World. A questionnaire in which the subjects are asked about the reasons for their decision shows that, at least in this case, moral motivations carry a heavy weight in the decision: the majority of dictators give the money for reasons of a consequentialist nature. Based on the results presented here and of other analogous experiments, we conclude that dicator behavior can be understood in terms of moral distance rather than social distance and that it systematically deviates from the egoism assumption in economic models and game theory. %extit{JEL}: A13, C72, C91

  5. [Distance learning in medical education]. (United States)

    Kudumović, Mensura; Masić, Izet; Novo, Ahmed; Masic, Zlatan; Omerhodzic, Ibrahim


    Distance learning or learning from the distance represents the educative technique with occupies all more significant place in the actual medical education of the healthcare workers at the international plan, specuale in the domains of the postgraduated and continuous medical education. It represents the educative technique of the significant effectivness, wich has to have at the disposal both adequate technological infrastructure as well as the previous education of the lecturer and users, adapted teaching plans and evaluation mechanisms of knowledge. By use of the rich choice of technological models, in relation to the traditional method of learning, enables the simultaneous education to the great number of students of the various profiles, the approach to all the relevant data basis as well as the mechanism of the evaluation knowledge institutions and the lectures.

  6. Tuning the Cepheid distance scale (United States)

    Mateo, Mario


    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.

  7. Distance probes of dark energy

    Energy Technology Data Exchange (ETDEWEB)

    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.


    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.

  8. Qualitative Visualization of Distance Information


    Heitzig, Jobst


    Different types of two- and three-dimensional representations of a finite metric space are studied that focus on the accurate representation of the linear order among the distances rather than their actual values. Lower and upper bounds for representability probabilities are produced by experiments including random generation, a rubber-band algorithm for accuracy optimization, and automatic proof generation. It is proved that both farthest neighbour representations and cluster tree representa...

  9. Nominal Ocular Dazzle Distance (NODD) (United States)


    for laser eye dazzle is presented together with calculations for laser safety applications based on the newly defined Maximum Dazzle Exposure (MDE...quantify the impact of laser eye dazzle on human performance. This allows the calculation of the MDE, the threshold laser irradiance below which 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

  10. Differential games

    CERN Document Server

    Friedman, Avner


    This volume lays the mathematical foundations for the theory of differential games, developing a rigorous mathematical framework with existence theorems. It begins with a precise definition of a differential game and advances to considerations of games of fixed duration, games of pursuit and evasion, the computation of saddle points, games of survival, and games with restricted phase coordinates. Final chapters cover selected topics (including capturability and games with delayed information) and N-person games.Geared toward graduate students, Differential Games will be of particular interest

  11. Effects of intermittent ladder-climbing exercise training on mitochondrial biogenesis and endoplasmic reticulum stress of the cardiac muscle in obese middle-aged rats. (United States)

    Kim, Kijin; Ahn, Nayoung; Jung, Suryun; Park, Solee


    The aim of this study is to investigate the effects of intermittent ladder-climbing exercise training on mitochondrial biogenesis and ER stress of the cardiac muscle in high fat diet-induced obese middle-aged rats. We induced obesity over 6 weeks of period in 40 male Sprague-Dawley rats around 50 weeks old, and were randomly divided into four experimental groups: chow, HFD, exercise+HFD, and exercise+chow. The exercising groups underwent high-intensity intermittent training using a ladder-climbing and weight exercise 3 days/week for a total of 8 weeks. High-fat diet and concurrent exercise resulted in no significant reduction in body weight but caused a significant reduction in visceral fat weight (p<0.05). Expression of PPARδ increased in the exercise groups and was significantly increased in the high-fat diet+exercise group (p<0.05). Among the ER stress-related proteins, the expression levels of p-PERK and CHOP, related to cardiac muscle damage, were significantly higher in the cardiac muscle of the high-fat diet group (p<0.05), and were significantly reduced by intermittent ladder-climbing exercise training (p<0.05). Specifically, this reduction was greater when the rats underwent exercise after switching back to the chow diet with a reduced caloric intake. Collectively, these results suggest that the combination of intermittent ladder-climbing exercise training and a reduced caloric intake can decrease the levels of ER stress-related proteins that contribute to cardiac muscle damage in obesity and aging. However, additional validation is required to understand the effects of these changes on mitochondrial biogenesis during exercise.

  12. Support Services for Distance Education

    Directory of Open Access Journals (Sweden)

    Sandra Frieden


    Full Text Available The creation and operation of a distance education support infrastructure requires the collaboration of virtually all administrative departments whose activities deal with students and faculty, and all participating academic departments. Implementation can build on where the institution is and design service-oriented strategies that strengthen institutional support and commitment. Issues to address include planning, faculty issues and concerns, policies and guidelines, approval processes, scheduling, training, publicity, information-line operations, informational materials, orientation and registration processes, class coordination and support, testing, evaluations, receive site management, partnerships, budgets, staffing, library and e-mail support, and different delivery modes (microwave, compressed video, radio, satellite, public television/cable, video tape and online. The process is ongoing and increasingly participative as various groups on campus begin to get involved with distance education activities. The distance education unit must continuously examine and revise its processes and procedures to maintain the academic integrity and service excellence of its programs. It’s a daunting prospect to revise the way things have been done for many years, but each department has an opportunity to respond to new ways of serving and reaching students.

  13. Teaching Chemistry via Distance Education (United States)

    Boschmann, Erwin


    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.

  14. Cortical and subcortical lesions impair skilled walking in the ladder rung walking test: a new task to evaluate fore- and hindlimb stepping, placing, and co-ordination. (United States)

    Metz, Gerlinde A; Whishaw, Ian Q


    The ladder rung walking test is a new task to assess skilled walking and measure both forelimb and hindlimb placing, stepping, and inter-limb co-ordination. Rats spontaneously walk from a starting location to a goal along a horizontal ladder. The spacing between the rungs of the ladder is variable and can be changed to prevent the animal from learning either the absolute or relative location of the rungs. The testing procedure requires minimal training and allows detailed quantitative and qualitative analysis using video recording. The utility of the test is described with postoperative data obtained from animals with unilateral neocortical strokes produced by pial stripping over the motor cortex, neonatal and adult unilateral corticospinal tract lesions produced by tract section at the pyramids, and unilateral dopamine depletions produced by injection of 6-hydroxydopamine into the nigrostriatal bundle. In addition, a group of aged rats was examined. Deficits in limb placing, stepping and co-ordination displayed by the animals demonstrate that this test can discriminate between lesions of the motor system or age-associated impairments. The test is useful for assessing loss and recovery of function due to brain or spinal cord injury, the effectiveness of treatment therapies, as well as compensatory processes through which animals adapt to nervous system injury.

  15. Differential Geometry

    CERN Document Server

    Stoker, J J


    This classic work is now available in an unabridged paperback edition. Stoker makes this fertile branch of mathematics accessible to the nonspecialist by the use of three different notations: vector algebra and calculus, tensor calculus, and the notation devised by Cartan, which employs invariant differential forms as elements in an algebra due to Grassman, combined with an operation called exterior differentiation. Assumed are a passing acquaintance with linear algebra and the basic elements of analysis.

  16. Differential magnetic force microscope imaging. (United States)

    Wang, Ying; Wang, Zuobin; Liu, Jinyun; Hou, Liwei


    This paper presents a method for differential magnetic force microscope imaging based on a two-pass scanning procedure to extract differential magnetic forces and eliminate or significantly reduce background forces with reversed tip magnetization. In the work, the difference of two scanned images with reversed tip magnetization was used to express the local magnetic forces. The magnetic sample was first scanned with a low lift distance between the MFM tip and the sample surface, and the magnetization direction of the probe was then changed after the first scan to perform the second scan. The differential magnetic force image was obtained through the subtraction of the two images from the two scans. The theoretical and experimental results have shown that the proposed method for differential magnetic force microscope imaging is able to reduce the effect of background or environment interference forces, and offers an improved image contrast and signal to noise ratio (SNR). © Wiley Periodicals, Inc.

  17. Moving up the ladder or stuck on the bottom rung? Homeownership as a solution to poverty in urban South Africa. (United States)

    Lemanski, Charlotte


    In the global South, policies providing property titles to low-income households are increasingly implemented as a solution to poverty. Integrating poor households into the capitalist economy using state-subsidized homeownership is intended to provide poor people with an asset that can be used in a productive manner. In this article the South African "housing subsidy system" is assessed using quantitative and qualitative data from in-depth research in a state-subsidized housing settlement in the city of Cape Town. The findings show that while state-subsidized property ownership provides long-term shelter and tenure security to low-income households, houses have mixed value as a financial asset. Although state-subsidized houses in South Africa are a financially tradable asset, transaction values are too low for low-income vendors to reach the next rung on the housing ladder, the township market. Furthermore, low-income homeowners are reticent to use their (typically primary) asset as collateral security for credit, and thus property ownership is not providing the financial returns that titling theories assume.

  18. Ladder beam and camera video recording system for evaluating forelimb and hindlimb deficits after sensorimotor cortex injury in rats. (United States)

    Soblosky, J S; Colgin, L L; Chorney-Lane, D; Davidson, J F; Carey, M E


    Hindlimb and forelimb deficits in rats caused by sensorimotor cortex lesions are frequently tested by using the narrow flat beam (hindlimb), the narrow pegged beam (hindlimb and forelimb) or the grid-walking (forelimb) tests. Although these are excellent tests, the narrow flat beam generates non-parametric data so that using more powerful parametric statistical analyses are prohibited. All these tests can be difficult to score if the rat is moving rapidly. Foot misplacements, especially on the grid-walking test, are indicative of an ongoing deficit, but have not been reliably and accurately described and quantified previously. In this paper we present an easy to construct and use horizontal ladder-beam with a camera system on rails which can be used to evaluate both hindlimb and forelimb deficits in a single test. By slow motion videotape playback we were able to quantify and demonstrate foot misplacements which go beyond the recovery period usually seen using more conventional measures (i.e. footslips and footfaults). This convenient system provides a rapid and reliable method for recording and evaluating rat performance on any type of beam and may be useful for measuring sensorimotor recovery following brain injury.

  19. Motor deficits on a ladder rung task in male and female adolescent and adult CGG knock-in mice. (United States)

    Hunsaker, Michael R; von Leden, Ramona E; Ta, Binh T; Goodrich-Hunsaker, Naomi J; Arque, Gloria; Kim, Kyoungmi; Willemsen, Rob; Berman, Robert F


    The fragile X premutation is a tandem CGG trinucleotide repeat expansion on the FMR1 gene between 55 and 200 repeats in length. A CGG knock-in (CGG KI) mouse with CGG trinucleotide repeat lengths between 70 and 350 has been developed and used to model the histopathology and cognitive deficits reported in carriers of the fragile X premutation. Previous studies have shown that CGG KI mice show progressive deficits in processing spatial and temporal information. To characterize the motor deficits associated with the fragile X premutation, male and female CGG KI mice ranging from 2 to 16 months of age with trinucleotide repeats ranging from 72 to 240 CGG in length were tested for their ability to perform a skilled ladder rung walking test. The results demonstrate that both male and female CGG KI mice showed a greater number of foot slips as a function of increased CGG repeat length, independent of the age of the animal or general activity level. Copyright © 2011 Elsevier B.V. All rights reserved.

  20. Unique Reversible Crystal-to-Crystal Phase Transition – Structural and Functional Properties of Fused Ladder Thienoarenes

    KAUST Repository

    Abe, Yuichiro


    Donor-acceptor type molecules based on fused ladder thienoarenes, indacenodithiophene (IDT) and dithienocyclopenta-thienothiophene (DTCTT), coupled with benzothiadiazole, are prepared and their solid-state structures are investigated. They display a rich variety of solid phases ranging from amorphous glass states to crystalline states, upon changes in the central aromatic core and side group structures. Most notably, the DTCTT-based derivatives showed reversible crystal-to-crystal phase transitions in heating and cooling cycles. Unlike what has been seen in π−conjugated molecules variable temperature XRD revealed that structural change occurs continuously during the transition. A columnar self-assembled structure with slip-stacked π−π interaction is proposed to be involved in the solid-state. This research provides the evidence of unique structural behavior of the DTCTT-based molecules through the detailed structural analysis. This unique structural transition paves the way for these materials to have self-healing of crystal defects, leading to improved optoelectronic properties.

  1. Crystal growth under high pressure: preparation of the spin-ladder compound SrCu sub 2 O sub 3

    CERN Document Server

    Loeffert, A; Assmus, W


    The two-leg ladder SrCu sub 2 O sub 3 belongs to the homologous series Sr sub n sub sub - sub 1 Cu sub n O sub 2 sub n sub - sub 1 and was first synthesized by Hiroi et al (Hiroi Z, Azuma M, Takano M and Bando Y 1991 J. Solid State Chem. 95 230). Due to the massive reaction of the sample material with the crucible (Au or Pt), only short reaction times up to 30 min have been used typically. We suggest an improved composite crucible with a single-crystalline MgO inset in a sealed Pt capsule and demonstrate its capability for single-crystal growth of SrCu sub 2 O sub 3. Experiments with a typical duration of 15 h were conducted at pressures between 3 and 6 GPa at temperatures between 950 and 1500 deg. C. Slow cooling of the melt effected directed growth of the first SrCu sub 2 O sub 3 milimetre-sized single crystals.

  2. Distance Measurement Solves Astrophysical Mysteries (United States)


    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

  3. Anxiety and Resistance in Distance Learning

    Directory of Open Access Journals (Sweden)

    Nazime Tuncay


    Full Text Available The purpose of this study was to investigate students' anxiety and resistance towards learning through distance education.Specifically, the study sought answers to the following questions: -What are the reasons of students not choosing distancelearning courses? -Which symptoms of anxiety, if any, do distance learner’s exhibit towards distance learning? Does genderhave any significant relationships with distance learners' perception of factors that affect their anxiety and resistance? A totalof 120 distance education students in Near East University were observed and 96 of them were interviewed. Computer anxiety,language anxiety, social anxiety were observed to be among the reasons of students’ resistance to distance learning.

  4. Quantum chromodynamics at large distances

    International Nuclear Information System (INIS)

    Arbuzov, B.A.


    Properties of QCD at large distances are considered in the framework of traditional quantum field theory. An investigation of asymptotic behaviour of lower Green functions in QCD is the starting point of the approach. The recent works are reviewed which confirm the singular infrared behaviour of gluon propagator M 2 /(k 2 ) 2 at least under some gauge conditions. A special covariant gauge comes out to be the most suitable for description of infrared region due to absence of ghost contributions to infrared asymptotics of Green functions. Solutions of Schwinger-Dyson equation for quark propagator are obtained in this special gauge and are shown to possess desirable properties: spontaneous breaking of chiral invariance and nonperturbative character. The infrared asymptotics of lower Green functions are used for calculation of vacuum expectation values of gluon and quark fields. These vacuum expectation values are obtained in a good agreement with the corresponding phenomenological values which are needed in the method of sum rules in QCD, that confirms adequacy of the infrared region description. The consideration of a behaviour of QCD at large distances leads to the conclusion that at contemporary stage of theory development one may consider two possibilities. The first one is the well-known confinement hypothesis and the second one is called incomplete confinement and stipulates for open color to be observable. Possible manifestations of incomplete confinement are discussed

  5. Determining distances using asteroseismic methods

    DEFF Research Database (Denmark)

    Aguirre, Victor Silva; Casagrande, L.; Basu, Sarbina


    Asteroseismology has been extremely successful in determining the properties of stars in different evolutionary stages with a remarkable level of precision. However, to fully exploit its potential, robust methods for estimating stellar parameters are required and independent verification of the r......Asteroseismology has been extremely successful in determining the properties of stars in different evolutionary stages with a remarkable level of precision. However, to fully exploit its potential, robust methods for estimating stellar parameters are required and independent verification...... of the results is needed. In this talk, I present a new technique developed to obtain stellar properties by coupling asteroseismic analysis with the InfraRed Flux Method. Using two global seismic observables and multi-band photometry, the technique determines masses, radii, effective temperatures, bolometric...... fluxes, and thus distances for field stars in a self-consistent manner. Applying our method to a sample of solar-like oscillators in the {\\it Kepler} field that have accurate {\\it Hipparcos} parallaxes, we find agreement in our distance determinations to better than 5%. Comparison with measurements...

  6. Mental models of learning in distance education. (United States)

    Richardson, John T E


    Interview-based research has shown that students in higher education hold a number of different conceptions of learning and of themselves as learners. There is debate about whether these conceptions constitute a developmental hierarchy. This study evaluated the Mental Models section of Vermunt and van Rijswijk's (1988) Inventory of Learning Styles (ILS) as a measure of students' conceptions of learning and sought to identify conceptions of learning as qualitatively different patterns of scores. A random sample of 1,000 students who were taking courses by distance learning with the Open University in the UK. A translated and adapted version of the Mental Models section of the ILS was administered in a postal survey. Complete data were obtained from 441 students and were subjected to principal component analysis, cluster analysis and discriminant analysis. The five scales in the Mental Models section of the ILS were homogeneous and achieved a satisfactory level of internal consistency, but two of the five scales could not be differentiated from each other in the students' responses. A cluster analysis identified four subgroups of students who had different patterns of scores on two discriminant functions. The four mental models identified in this study were broadly similar to those identified by Vermunt (1996) in an interview-based study. However, these do not seem to constitute a developmental hierarchy, and, following Vermunt, it is suggested that they are better interpreted as aspects of four over-arching 'learning styles' or 'learning patterns'.

  7. Large negative differential resistance in graphene nanoribbon superlattices (United States)

    Tseng, P.; Chen, C. H.; Hsu, S. A.; Hsueh, W. J.


    A graphene nanoribbon superlattice with a large negative differential resistance (NDR) is proposed. Our results show that the peak-to-valley ratio (PVR) of the graphene superlattices can reach 21 at room temperature with bias voltages between 90-220 mV, which is quite large compared with the one of traditional graphene-based devices. It is found that the NDR is strongly influenced by the thicknesses of the potential barrier. Therefore, the NDR effect can be optimized by designing a proper barrier thickness. The large NDR effect can be attributed to the splitting of the gap in transmission spectrum (segment of Wannier-Stark ladder) with larger thicknesses of barrier when the applied voltage increases.

  8. Open and Distance Learning Today. Routledge Studies in Distance Education Series. (United States)

    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…

  9. Toward an Internally Consistent Astronomical Distance Scale (United States)

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


    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.

  10. Distance Learning Plan Development: Initiating Organizational Structures

    National Research Council Canada - National Science Library

    Poole, Clifton


    .... Army distance learning plan managers to examine the DLPs they were directing. The analysis showed that neither army nor civilian distance learning plan managers used formalized requirements for organizational structure development (OSD...

  11. Anxiety and Resistance in Distance Learning


    Nazime Tuncay; Huseyin Uzunboylu


    The purpose of this study was to investigate students' anxiety and resistance towards learning through distance education.Specifically, the study sought answers to the following questions: -What are the reasons of students not choosing distancelearning courses? -Which symptoms of anxiety, if any, do distance learner’s exhibit towards distance learning? Does genderhave any significant relationships with distance learners' perception of factors that affect their anxiety and resistance? A totalo...

  12. Differential belongings

    DEFF Research Database (Denmark)

    Oldrup, Helene


    This paper explores suburban middle-class residents’ narratives about housing choice, everyday life and belonging in residential areas of Greater Copenhagen, Denmark, to understand how residential processes of social differentiation are constituted. Using Savage et al.’s concepts of discursive...

  13. Does Institutional Distance Still Matter?

    DEFF Research Database (Denmark)

    Møller Larsen, Marcus; Manning, Stephan


    ’ (CMMI) process standard adoption, we show that sourcing location choices are indeed negatively impacted by institutional differences between home and host country, i.e. ‘distance’ still matters, but they are positively impacted by CMMI standard adoption in host countries, and standard adoption......This paper adds nuance to our understanding of institutional antecedents of foreign investment, in particular in global services sourcing. While prior research has stressed the various risks and effects associated with home-host country differences in national-level institutions, e.g. legal systems...... negatively moderates the importance of distance. Findings promote a more contextual, multi-level understanding of institutional antecedents of foreign firm location choices, which also has important policy implications in particular for emerging economies....

  14. Does Institutional Distance Still Matter?

    DEFF Research Database (Denmark)

    Møller Larsen, Marcus; Manning, Stephan

    This paper adds nuance to our understanding of institutional antecedents of foreign investment, in particular in global services sourcing. While prior research has stressed the various risks and effects associated with home-host country differences in national-level institutions, e.g. legal systems......, we argue that industry-specific, yet often transnational field institutions, e.g. standards, have become critical factors in driving sourcing location decisions. Using data from the Offshoring Research Network, Kaufmann institutional indicators, and data on ‘capability maturity model integration...... negatively moderates the importance of distance. Findings promote a more contextual, multi-level understanding of institutional antecedents of foreign firm location choices, which also has important policy implications in particular for emerging economies....

  15. Managerial Distance and Virtual Ownership

    DEFF Research Database (Denmark)

    Hansmann, Henry; Thomsen, Steen

    Industrial foundations are autonomous nonprofit entities that own and control one or more conventional business firms. These foundations are common in Northern Europe, where they own a number of internationally prominent companies. Previous studies have indicated, surprisingly, that companies...... controlled by industrial foundations are, on average, as profitable as companies with conventional patterns of investor ownership. In this article, we explore the reasons for this performance, not by comparing foundation-owned firms with conventional investor-owned firms, but rather by focusing...... on differences among the industrial foundations themselves. We work with a rich data set comprising 113 foundation-owned Danish companies over the period 2003-2008. We focus in particular on a composite structural factor that we term “managerial distance.” We propose this as a measure of the extent to which...

  16. Elasticity of Long Distance Travelling

    DEFF Research Database (Denmark)

    Knudsen, Mette Aagaard


    With data from the Danish expenditure survey for 12 years 1996 through 2007, this study analyses household expenditures for long distance travelling. Household expenditures are examined at two levels of aggregation having the general expenditures on transportation and leisure relative to five other...... aggregated commodities at the highest level, and the specific expenditures on plane tickets and travel packages at the lowest level. The Almost Ideal Demand System is applied to determine the relationship between expenditures on transportation and leisure and all other purchased non-durables within...... packages has higher income elasticity of demand than plane tickets but also higher than transportation and leisure in general. The findings within price sensitiveness are not as sufficient estimated, but the model results indicate that travel packages is far more price elastic than plane tickets which...

  17. Snakes and ladders: the barriers and facilitators of elective hip- and knee-replacement surgery in Australian public hospitals. (United States)

    Walters, Julie L; Mackintosh, Shylie F; Sheppard, Lorraine


    Waiting lists for elective surgery are a persistent problem faced by health systems. The progression through elective surgery waiting lists can be likened to a game of snakes and ladders where barriers (snakes) delay access to surgery and facilitators (ladders) expedite access. The aim of the present study was to describe the barriers and facilitators to delivery of total hip- and total knee-replacement surgery in South Australian public-funded hospitals. Semistructured interviews with staff, direct observation of administrative processes and documentation analysis were combined under a systems theory framework. System barriers (snakes) were grouped into five categories: resources, workload, hospital engagement, community engagement and system processes. Inadequate resources was the most prominent barrier, patient cancellations resulted in one-third of administrative tasks being repeated and there was a perceived lack of engagement to maximising efficiency. Interestingly, despite a lack of resources being perceived to be the biggest problem, additional resources without system change was not considered an effective long-term strategy. Given the complexity of the elective surgery system, it is not surprising that single-item reforms have not created lasting reductions in waiting times. Multifaceted, whole-system reforms may be more successful. WHAT IS KNOWN ABOUT THE TOPIC? Waiting lists and waiting times for surgery are controversial, associated with frequent reforms and negative emotive headlines. We know from existing literature and anecdotal reports that individuals frequently experience lengthy delays before receiving elective surgery. Anecdotal reports also suggest that there are inefficiencies within elective surgery systems that contribute to these delays and result in cancellations, patient deterioration and poor overall satisfaction with the public health system in Australia. What isn't clear is whether this perception is accurate and what inefficiencies

  18. Analysing designed experiments in distance sampling (United States)

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


    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...

  19. ETUDE - European Trade Union Distance Education. (United States)

    Creanor, Linda; Walker, Steve


    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…

  20. What Is Distance? Popular Lectures in Mathematics. (United States)

    Shreider, Yu A.

    Presented is an elaboration of a course given at Moscow University for pupils in ninth and tenth grades. The development through abstraction of the general definition of distance is discussed and a class of spaces in which the notion of distance is defined, the so-called metric spaces, is introduced. The general concept of distance is related to a…

  1. Continuity Properties of Distances for Markov Processes

    DEFF Research Database (Denmark)

    Jaeger, Manfred; Mao, Hua; Larsen, Kim Guldstrand


    In this paper we investigate distance functions on finite state Markov processes that measure the behavioural similarity of non-bisimilar processes. We consider both probabilistic bisimilarity metrics, and trace-based distances derived from standard Lp and Kullback-Leibler distances. Two desirable...

  2. Distance learning: its advantages and disadvantages




    Distance learning has become popular in higher institutions because of its flexibility and availability to learners and teachers at anytime, regardless of geographic location. With so many definitions and phases of distance education, this paper only focuses on the delivery mode of distance education (the use of information technology), background, and its disadvantages and advantages for today’s learners.

  3. Haptacyclic Carbazole-Based Ladder-Type Nonfullerene Acceptor with Side-Chain Optimization for Efficient Organic Photovoltaics. (United States)

    Hsiao, Yu-Tang; Li, Chia-Hua; Chang, Shao-Ling; Heo, Soowon; Tajima, Keisuke; Cheng, Yen-Ju; Hsu, Chain-Shu


    In this research, a haptacyclic carbazole-based dithienocyclopentacarbazole (DTCC) ladder-type structure was formylated to couple with two 1,1-dicyanomethylene-3-indanone (IC) moieties, forming a new nonfullerene acceptor DTCCIC-C17 using a bulky branched 1-octylnonayl side chain at the nitrogen of the embedded carbazole and four 4-octylphenyl groups at the sp 3 -carbon bridges. The rigid and coplanar main-chain backbone of the DTCC core provides a broad light-absorbing window and a higher-lying LUMO energy level, whereas the bulky flanked side chains reduce intermolecular interactions, making DTCCIC-C17 amorphous with excellent solution processability. The DTCCIC-C17 as an acceptor is combined with a medium band gap polymer poly[(2,6-(4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)-benzo[1,2-b:4,5-b']dithiophene))-alt-(5,5-(1',3'-di-2-thienyl-5',7'-bis(2-ethylhexyl)benzo[1',2'-c:4',5'-c']dithiophene-4,8-dione))] (PBDB-T) as the donor in the active layer to obtain suitable highest occupied molecular orbital/lowest unoccupied molecular orbital energy alignments and complimentary absorption. The devices with an inverted configuration (ITO/ZnO/active layer/MoO 3 /Ag) without using an aqueous poly(3,4-ethylenedioxythiophene) polystyrene sulfonate layer were fabricated for better device stability. When the diiodooctane-treated PBDB-T:DTCCIC-C17 active layer was thermally annealed at 50 °C for 10 min, the device achieved the highest efficiency of 9.48% with a high V oc of 0.98 V, a J sc of 14.27 mA cm -2 , and an FF of 0.68.

  4. [Encouraging healthy habits by playing with the child in the family milieu: the snakes and ladders game]. (United States)

    Sánchez Echenique, M; Pèlach, R


    In recent decades society has been undergoing many changes and these have had a strong incidence on infant morbidity and mortality. Diseases that have practically vanished due to the impact of vaccinations and the improvement of the standard of living have given way to others derived from the changes in eating habits and life style; accidents, on the other hand, have come to be the first cause of morbidity and mortality after the first year of life has been passed. Strategies must be directed towards avoiding the causes of this new way of falling ill. We present a Spanish version of a game similar to "snakes and ladders" called "the healthy goose", which encourages healthy living habits. In order that the child should internalize safe habits by means of the game, certain squares in the game have been replaced by positive drawings, in which the child carries out healthy activities, receiving prizes for these, and others in which risky activities are performed, which are penalized. The areas dealt with are: habits (nutrition, sleep, study, games, etc.), Accidents at home, road safety (pedestrian, cyclist and automobile traveler), and swimming pools. The game starts with a child of 3-4 years and the goal is reached as a healthy adolescent. Given that the variation in personalities is enormous, we believe the family milieu should be the complement to legislative and educational measures and general campaigns in the means of communication, since it is what the child knows best and where he learns his deepest attitudes. This game could be a help to parents in this difficult task.


    Directory of Open Access Journals (Sweden)

    Olivia Adwoa Tiwaah Frimpong KWAPONG


    Full Text Available Distance education (DE is seen as a tool for widening access to education at all levels. It is an educational tool that breaks most of the divides in education – age, gender, race, income, space, time etc. For the past decades, irrespective of the extensive expansion of tertiary institutions in the country, provision of tertiary education in Ghana has not been adequate enough to absorb all qualified applicants. This situation has peculiar effect on women who for socio-cultural factors drop out of formal education as they climb the ladder. The limited access to tertiary education has been the concern of various governments in the country. Various educational reforms have been made to this effect. In view of the exclusive potential of DE in widening access to education in a unique way, it has been recommended in the most recent educational reform that DE be promoted by establishing an open university and open colleges in addition to encouraging dual mode of delivery in the existing public universities. By its peculiar nature of being flexible and bridging space and time, studies have confirmed that DE has been an educational format that suits women’s study plans and learning styles. This paper explores the unique nature of DE for widening access to tertiary education most especially for women in Ghana and the issues to consider in the process.

  6. Generating Signed Distance Fields From Triangle Meshes

    DEFF Research Database (Denmark)

    Bærentzen, Jakob Andreas; Aanæs, Henrik

    A method for generating a discrete, signed 3D distance field is proposed. Distance fields are used in a number of contexts. In particular the popular level set method is usually initialized by a distance field. The main focus of our work is on simplifying the computation of the sign when generating....... This leads to a method for generating signed distance fields which is a simple and straightforward extension of the method for generating unsigned distance fields. We prove that our choice of pseudo normal leads to a correct technique for computing the sign....

  7. Galaxy Cluster Smashes Distance Record (United States)


    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

  8. Estimating rupture distances without a rupture (United States)

    Thompson, Eric M.; Worden, Charles


    Most ground motion prediction equations (GMPEs) require distances that are defined relative to a rupture model, such as the distance to the surface projection of the rupture (RJB) or the closest distance to the rupture plane (RRUP). There are a number of situations in which GMPEs are used where it is either necessary or advantageous to derive rupture distances from point-source distance metrics, such as hypocentral (RHYP) or epicentral (REPI) distance. For ShakeMap, it is necessary to provide an estimate of the shaking levels for events without rupture models, and before rupture models are available for events that eventually do have rupture models. In probabilistic seismic hazard analysis, it is often convenient to use point-source distances for gridded seismicity sources, particularly if a preferred orientation is unknown. This avoids the computationally cumbersome task of computing rupture-based distances for virtual rupture planes across all strikes and dips for each source. We derive average rupture distances conditioned on REPI, magnitude, and (optionally) back azimuth, for a variety of assumed seismological constraints. Additionally, we derive adjustment factors for GMPE standard deviations that reflect the added uncertainty in the ground motion estimation when point-source distances are used to estimate rupture distances.

  9. Learner characteristics involved in distance learning

    Energy Technology Data Exchange (ETDEWEB)

    Cernicek, A.T.; Hahn, H.A.


    Distance learning represents a strategy for leveraging resources to solve educational and training needs. Although many distance learning programs have been developed, lessons learned regarding differences between distance learning and traditional education with respect to learner characteristics have not been well documented. Therefore, we conducted a survey of 20 distance learning professionals. The questionnaire was distributed to experts attending the second Distance Learning Conference sponsored by Los Alamos National Laboratory. This survey not only acquired demographic information from each of the respondents but also identified important distance learning student characteristics. Significant distance learner characteristics, which were revealed statistically and which influence the effectiveness of distance learning, include the following: reading level, student autonomy, and self-motivation. Distance learning cannot become a more useful and effective method of instruction without identifying and recognizing learner characteristics. It will be important to consider these characteristics when designing all distance learning courses. This paper will report specific survey findings and their implications for developing distance learning courses. 9 refs., 6 tabs.

  10. Phylogenetic inference with weighted codon evolutionary distances. (United States)

    Criscuolo, Alexis; Michel, Christian J


    We develop a new approach to estimate a matrix of pairwise evolutionary distances from a codon-based alignment based on a codon evolutionary model. The method first computes a standard distance matrix for each of the three codon positions. Then these three distance matrices are weighted according to an estimate of the global evolutionary rate of each codon position and averaged into a unique distance matrix. Using a large set of both real and simulated codon-based alignments of nucleotide sequences, we show that this approach leads to distance matrices that have a significantly better treelikeness compared to those obtained by standard nucleotide evolutionary distances. We also propose an alternative weighting to eliminate the part of the noise often associated with some codon positions, particularly the third position, which is known to induce a fast evolutionary rate. Simulation results show that fast distance-based tree reconstruction algorithms on distance matrices based on this codon position weighting can lead to phylogenetic trees that are at least as accurate as, if not better, than those inferred by maximum likelihood. Finally, a well-known multigene dataset composed of eight yeast species and 106 codon-based alignments is reanalyzed and shows that our codon evolutionary distances allow building a phylogenetic tree which is similar to those obtained by non-distance-based methods (e.g., maximum parsimony and maximum likelihood) and also significantly improved compared to standard nucleotide evolutionary distance estimates.

  11. Distance Education at Silesian University of Technology

    Directory of Open Access Journals (Sweden)

    Piotr Klosowski


    Full Text Available This paper presents Distance Learning Platform used by Silesian University of Technology. Distance Learning Platform is based on modular object-oriented dynamic learning environment, represents LMS (Learning Management Systems technology, a software package designed to help educators create quality online courses. Currently on Distance Learning Platform at Silesian University of Technology are available over 520 online courses created for students of twelve University's faculties. Number of Distance Learning Platform users exceeds 12000. Distance Learning Platform works as typically asynchronous e-learning service, but in the future more synchronous e-learning services will be added. Distance Learning Platform has great potential to create a successful elearning experience by providing a plethora of excellent tools that can be used to enhance conventional classroom instruction, in hybrid courses, or any distance learning arrangements.

  12. Differential discriminator

    International Nuclear Information System (INIS)

    Dukhanov, V.I.; Mazurov, I.B.


    A principal flowsheet of a differential discriminator intended for operation in a spectrometric circuit with statistical time distribution of pulses is described. The differential discriminator includes four integrated discriminators and a channel of piled-up signal rejection. The presence of the rejection channel enables the discriminator to operate effectively at loads of 14x10 3 pulse/s. The temperature instability of the discrimination thresholds equals 250 μV/ 0 C. The discrimination level changes within 0.1-5 V, the level shift constitutes 0.5% for the filling ratio of 1:10. The rejection coefficient is not less than 90%. Alpha spectrum of the 228 Th source is presented to evaluate the discriminator operation with the rejector. The rejector provides 50 ns time resolution

  13. Differential topology

    CERN Document Server

    Margalef-Roig, J


    ...there are reasons enough to warrant a coherent treatment of the main body of differential topology in the realm of Banach manifolds, which is at the same time correct and complete. This book fills the gap: whenever possible the manifolds treated are Banach manifolds with corners. Corners add to the complications and the authors have carefully fathomed the validity of all main results at corners. Even in finite dimensions some results at corners are more complete and better thought out here than elsewhere in the literature. The proofs are correct and with all details. I see this book as a reliable monograph of a well-defined subject; the possibility to fall back to it adds to the feeling of security when climbing in the more dangerous realms of infinite dimensional differential geometry. Peter W. Michor

  14. Hepatocyte differentiation. (United States)

    Olsavsky Goyak, Katy M; Laurenzana, Elizabeth M; Omiecinski, Curtis J


    Increasingly, research suggests that for certain systems, animal models are insufficient for human toxicology testing. The development of robust, in vitro models of human toxicity is required to decrease our dependence on potentially misleading in vivo animal studies. A critical development in human toxicology testing is the use of human primary hepatocytes to model processes that occur in the intact liver. However, in order to serve as an appropriate model, primary hepatocytes must be maintained in such a way that they persist in their differentiated state. While many hepatocyte culture methods exist, the two-dimensional collagen "sandwich" system combined with a serum-free medium, supplemented with physiological glucocorticoid concentrations, appears to robustly maintain hepatocyte character. Studies in rat and human hepatocytes have shown that when cultured under these conditions, hepatocytes maintain many markers of differentiation including morphology, expression of plasma proteins, hepatic nuclear factors, phase I and II metabolic enzymes. Functionally, these culture conditions also preserve hepatic stress response pathways, such as the SAPK and MAPK pathways, as well as prototypical xenobiotic induction responses. This chapter will briefly review culture methodologies but will primarily focus on hallmark hepatocyte structural, expression and functional markers that characterize the differentiation status of the hepatocyte.

  15. Distance-weighted city growth. (United States)

    Rybski, Diego; García Cantú Ros, Anselmo; Kropp, Jürgen P


    Urban agglomerations exhibit complex emergent features of which Zipf's law, i.e., a power-law size distribution, and fractality may be regarded as the most prominent ones. We propose a simplistic model for the generation of citylike structures which is solely based on the assumption that growth is more likely to take place close to inhabited space. The model involves one parameter which is an exponent determining how strongly the attraction decays with the distance. In addition, the model is run iteratively so that existing clusters can grow (together) and new ones can emerge. The model is capable of reproducing the size distribution and the fractality of the boundary of the largest cluster. Although the power-law distribution depends on both, the imposed exponent and the iteration, the fractality seems to be independent of the former and only depends on the latter. Analyzing land-cover data, we estimate the parameter-value γ≈2.5 for Paris and its surroundings.


    Directory of Open Access Journals (Sweden)

    Gulsun KURUBACAK


    Full Text Available Distance Nurse Education is the first book in the Turkish literature. The main purpose of this book is to introduce and discuss the dimensions, components and characteristics of Distance Nurse Education. The unique approach of this publication brings together 1 Distance Education, 2 Nurse Education, and 3 ALINE (Active Learning in Nursing Education Model (Fay, Selz, and Johnson, 2005 together at the same time. This book focuses on the learning activities, learner-centered approach, interactions, nursing competency oriented skills and feedback of distance nurse education and its applications. Besides, this book considers on how planning, designing, delivering and managing distance resources to bring about the successful completion of the goals and objectives of distance nurse education; and also discusses the design and its models from a progressive and transformative viewpoint in the area. Thus, the publication attempts to build a better understanding on how distance educators, designers, tutors and learners in nurse education can talk about the methodical approaches to planning and guiding processes to design distance nurse education from start to finish. This is also important to scrutinize the distance nurse education model how to bring a global and multicultural partnership of faculty, administrators, professionals, teachers, community activists and researchers in distance education as well as nurse education.

  17. What differentiates a differential psychopharmacology?


    Krüger, Hans-Peter


    The methodological implications of a differential psychopharmacology are discussed. It is shown that the technique of stratifying subjects with personality scores depends on one basic assumption: the personality score is not affected by the other experimental factors. Two experiments are reported in which pre- and posttest (after the experiment) scores were measured. The pre-post-differences showed themselves to be affected by the medication. It is argued that in psychopharmacological experim...

  18. Differential geometry

    CERN Document Server

    Ciarlet, Philippe G


    This book gives the basic notions of differential geometry, such as the metric tensor, the Riemann curvature tensor, the fundamental forms of a surface, covariant derivatives, and the fundamental theorem of surface theory in a selfcontained and accessible manner. Although the field is often considered a classical one, it has recently been rejuvenated, thanks to the manifold applications where it plays an essential role. The book presents some important applications to shells, such as the theory of linearly and nonlinearly elastic shells, the implementation of numerical methods for shells, and

  19. Differential equations

    CERN Document Server

    Tricomi, FG


    Based on his extensive experience as an educator, F. G. Tricomi wrote this practical and concise teaching text to offer a clear idea of the problems and methods of the theory of differential equations. The treatment is geared toward advanced undergraduates and graduate students and addresses only questions that can be resolved with rigor and simplicity.Starting with a consideration of the existence and uniqueness theorem, the text advances to the behavior of the characteristics of a first-order equation, boundary problems for second-order linear equations, asymptotic methods, and diff

  20. Differential topology

    CERN Document Server

    Guillemin, Victor


    Differential Topology provides an elementary and intuitive introduction to the study of smooth manifolds. In the years since its first publication, Guillemin and Pollack's book has become a standard text on the subject. It is a jewel of mathematical exposition, judiciously picking exactly the right mixture of detail and generality to display the richness within. The text is mostly self-contained, requiring only undergraduate analysis and linear algebra. By relying on a unifying idea-transversality-the authors are able to avoid the use of big machinery or ad hoc techniques to establish the main

  1. Evaluation of the 'Ladder to the Moon, Culture Change Studio Engagement Programme' staff training: Two quasi-experimental case studies. (United States)

    Guzmán, Azucena; Wenborn, Jennifer; Swinson, Tom; Orrell, Martin


    To evaluate the impact of the CCSEP on care home staff in two care settings for older people in one nursing home and one residential home. Care homes provide personal care and accommodation for older people. The English Dementia Strategy aims to improve the quality of service provision for people with dementia. This includes specific mention of improving the quality of life in care homes and as such includes objectives related to developing the workforce knowledge and skills. The Ladder to the Moon Culture Change Studio Engagement Programme (CCSEP) is a staff training approach based on the Positive Psychology framework that uses theatre- and film-based activities. This study used a wait-list controlled design. However, the data analysis plan was amended to reflect difficulties in data collection, and a quasi-experimental case study approach was consequently utilised. Outcome measures for staff attitudes and beliefs were as follows: Sense of Competence in Dementia Care Staff; Approaches to Dementia Questionnaire; Job Satisfaction Index; Brief Learning Transfer System Inventory; and Scale of Positive and Negative Experience. The Quality of Interaction Schedule (QUIS) was used to observe changes in staff-resident interaction. Fifty staff in two care homes completed the questionnaires and forty-one undertook formal CCSEP training. In Home A (nursing home), there was no significant change in any of the measures. In Home B (residential home), the QUIS showed an increase in positive interactions post intervention; a significant increase in the Building Relationship subscale of Sense of Competence; and a significant increase in staff sense of hopefulness towards people with dementia. The Brief Learning Transfer System Inventory showed a significant decrease post-intervention. The intervention did not significantly affect the happiness or job satisfaction of care home staff. The results of this study provide tentative evidence about the efficacy of this staff training

  2. Distance and Cable Length Measurement System (United States)

    Hernández, Sergio Elias; Acosta, Leopoldo; Toledo, Jonay


    A simple, economic and successful design for distance and cable length detection is presented. The measurement system is based on the continuous repetition of a pulse that endlessly travels along the distance to be detected. There is a pulse repeater at both ends of the distance or cable to be measured. The endless repetition of the pulse generates a frequency that varies almost inversely with the distance to be measured. The resolution and distance or cable length range could be adjusted by varying the repetition time delay introduced at both ends and the measurement time. With this design a distance can be measured with centimeter resolution using electronic system with microsecond resolution, simplifying classical time of flight designs which require electronics with picosecond resolution. This design was also applied to position measurement. PMID:22303169





    Nursing that the reason of its essence arises from social requirements is a practical discipline. It requires knowledge and skills. This knowledge and skills must be updated with developments in the health field. However, because of their living conditions, nurses cannot continue the formal education. Distance nursing programs provide flexibility to them. In this study will be handed the importance of distance education for nursing and the attitudes of nurses towards distance nursing programs.

  4. Distance Secondary Education in Rural Latin America


    Rosemary Raygada, Watanabe; KUBOTA, Kenichi


    Latin American countries have been implementing a new system of distance teaching-learning, especially for those rural students living in remote poor areas. The main features behind the distance education projects are the followings: 1) Centralized management by the head offices of the Ministries of Education, 2) Although parents and communities are motivated to collaborate with the government in developing distance education, economic resources are lacking, 3) Rural teacher’s working conditi...

  5. Robustness of Distance-to-Default

    DEFF Research Database (Denmark)

    Jessen, Cathrine; Lando, David


    . A notable exception is a model with stochastic volatility of assets. In this case both the ranking of firms and the estimated default probabilities using distance-to-default perform significantly worse. We therefore propose a volatility adjustment of the distance-to-default measure, that significantly...... simulations to investigate the robustness of the distance-to-default measure to different model specifications. Overall we find distance-to-default to be robust to a number of deviations from the simple Merton model that involve different asset value dynamics and different default triggering mechanisms...

  6. Distance Education in Turkish Higher Education

    Directory of Open Access Journals (Sweden)

    Ömür AKDEMİR


    Full Text Available The term distance education is used to define education where educators and learners are physically separated. The first use of the distance education as a term goes back to 1924 in Turkey. Establishment of the Open Education Faculty of Anadolu University is the first initiative for the appearance of distance education in the Turkish Higher Education. Distance education is offered at different levels of higher education at present. Changes happening in technology and students characteristics in higher education over the years have made distance education delivered over the internet popular. Systems used to offer education over the internet are called Learning Management Systems. Commercial and non-commercial Learning Management Systems are available and used in different level of higher education to offer distance education. Programs and Learning Management Systems preferred to offer distance education over the internet in Turkish Higher Education are investigated in this study. Results of the study indicated that Management and Computer Technology programs are dominantly preferred in various level of the Turkish Higher Education. It was also found that commercially and open source freely available Learning Management Systems are also used to offer distance education in the Turkish Higher Education. It seems that distance education programs in higher education will continue to grow to respond to the changing needs of students.

  7. A cognitively grounded measure of pronunciation distance.

    Directory of Open Access Journals (Sweden)

    Martijn Wieling

    Full Text Available In this study we develop pronunciation distances based on naive discriminative learning (NDL. Measures of pronunciation distance are used in several subfields of linguistics, including psycholinguistics, dialectology and typology. In contrast to the commonly used Levenshtein algorithm, NDL is grounded in cognitive theory of competitive reinforcement learning and is able to generate asymmetrical pronunciation distances. In a first study, we validated the NDL-based pronunciation distances by comparing them to a large set of native-likeness ratings given by native American English speakers when presented with accented English speech. In a second study, the NDL-based pronunciation distances were validated on the basis of perceptual dialect distances of Norwegian speakers. Results indicated that the NDL-based pronunciation distances matched perceptual distances reasonably well with correlations ranging between 0.7 and 0.8. While the correlations were comparable to those obtained using the Levenshtein distance, the NDL-based approach is more flexible as it is also able to incorporate acoustic information other than sound segments.

  8. Machine learning enhanced optical distance sensor (United States)

    Amin, M. Junaid; Riza, N. A.


    Presented for the first time is a machine learning enhanced optical distance sensor. The distance sensor is based on our previously demonstrated distance measurement technique that uses an Electronically Controlled Variable Focus Lens (ECVFL) with a laser source to illuminate a target plane with a controlled optical beam spot. This spot with varying spot sizes is viewed by an off-axis camera and the spot size data is processed to compute the distance. In particular, proposed and demonstrated in this paper is the use of a regularized polynomial regression based supervised machine learning algorithm to enhance the accuracy of the operational sensor. The algorithm uses the acquired features and corresponding labels that are the actual target distance values to train a machine learning model. The optimized training model is trained over a 1000 mm (or 1 m) experimental target distance range. Using the machine learning algorithm produces a training set and testing set distance measurement errors of error is at least a factor of 4 improvement over our prior sensor demonstration without the use of machine learning. Applications for the proposed sensor include industrial scenario distance sensing where target material specific training models can be generated to realize low error distance measurements.

  9. (C5H12NCu2Br3: A Piperidinium Copper(I Bromide with [Cu2Br3]− Ladders

    Directory of Open Access Journals (Sweden)

    Karl W. Krämer


    Full Text Available Piperidinium copper(I bromide, (C5H12NCu2Br3, was obtained from a solution of CuBr2, piperidine, and HBr in ethanol. At 60 °C ethanol slowly reduces copper(II to copper(I. Colorless plates of (C5H12NCu2Br3 crystallize in the triclinic space group P-1 with lattice parameters of a = 6.2948(10 Å, b = 8.2624(14 Å, c = 10.7612(17 Å, α = 75.964(19°, β = 89.232(19°, γ = 84.072(19°, and Z = 2 at 173 K. [CuBr4] tetrahedra share edges and form [Cu2Br3]− ladders parallel to the a-axis. (C5H12N+ ions adopt a chair conformation and connect the [Cu2Br3]− ladders via H-bonding. The (C5H12NCu2Br3 structure is related to the mineral rasvumite, KFe2S3, space group Cmcm, which is isostructural to several alkali copper(I halides.

  10. Phase transitions and thermal entanglement of the distorted Ising-Heisenberg spin chain: topology of multiple-spin exchange interactions in spin ladders (United States)

    Arian Zad, Hamid; Ananikian, Nerses


    We consider a symmetric spin-1/2 Ising-XXZ double sawtooth spin ladder obtained from distorting a spin chain, with the XXZ interaction between the interstitial Heisenberg dimers (which are connected to the spins based on the legs via an Ising-type interaction), the Ising coupling between nearest-neighbor spins of the legs and rungs spins, respectively, and additional cyclic four-spin exchange (ring exchange) in the square plaquette of each block. The presented analysis supplemented by results of the exact solution of the model with infinite periodic boundary implies a rich ground state phase diagram. As well as the quantum phase transitions, the characteristics of some of the thermodynamic parameters such as heat capacity, magnetization and magnetic susceptibility are investigated. We prove here that among the considered thermodynamic and thermal parameters, solely heat capacity is sensitive versus the changes of the cyclic four-spin exchange interaction. By using the heat capacity function, we obtain a singularity relation between the cyclic four-spin exchange interaction and the exchange coupling between pair spins on each rung of the spin ladder. All thermal and thermodynamic quantities under consideration should be investigated by regarding those points which satisfy the singularity relation. The thermal entanglement within the Heisenberg spin dimers is investigated by using the concurrence, which is calculated from a relevant reduced density operator in the thermodynamic limit.

  11. Ultra-wideband ladder filters using zero-th shear mode plate wave in ultrathin LiNbO3 plate with apodized interdigital transducers (United States)

    Kadota, Michio; Tanaka, Shuji


    There are two kinds of plate waves propagating in a thin plate, Lamb and shear horizontal (SH) waves. The former has a velocity higher than 15,000 m/s when the plate is very thin. On the contrary, 0th SH (SH0) mode plate wave in an ultrathin LiNbO3 plate has an electro-mechanical coupling factor larger than 50%. Authors fabricated an ultra-wideband T-type ladder filter with a relative bandwidth (BW) of 41% using the SH0 mode plate wave. Although the BW of the filter fully covers the digital TV band in Japan, it does not have sufficient margin at the lower and higher end of BW. Besides, periodic small ripples due to transverse mode in pass-band of the filter were observed. In this study π-type ladder filters were fabricated by changing the pitch ratio of interdigital transducer (IDT) of parallel and series arm resonators (PR(IDT)) to control the BW, and by apodizing IDTs to improve the periodic small ripples due to transverse mode. Ultra-wideband filters without periodic small transverse mode with ultrawide bandwidth from 41 to 49% were fabricated. The BWs fully cover ultrawide digital television bands in Japan and U.S.A. These filters with an ultrawide BW and a steep characteristic show the possibility to be applied to a reported cognitive radio system and other communication systems requiring an ultrawide BW.

  12. Ground state of a spin-1/2 Heisenberg-Ising two-leg ladder with XYZ intra-rung coupling

    Directory of Open Access Journals (Sweden)

    T. Verkholyak


    Full Text Available The quantum spin-1/2 two-leg ladder with an anisotropic XYZ Heisenberg intra-rung interaction and Ising inter-rung interactions is treated by means of a rigorous approach based on the unitary transformation. The particular case of the considered model with X-X intra-rung interaction resembles a quantum compass ladder with additional frustrating diagonal Ising interactions. Using an appropriately chosen unitary transformation, the model under investigation may be reduced to a transverse Ising chain with composite spins, and one may subsequently find the ground state quite rigorously. We obtain a ground-state phase diagram and analyze the interplay of the competition between several factors: the XYZ anisotropy in the Heisenberg intra-rung coupling, the Ising interaction along the legs, and the frustrating diagonal Ising interaction. The investigated model shows extraordinarily diverse ground-state phase diagrams including several unusual quantum ordered phases, two different disordered quantum paramagnetic phases, as well as discontinuous or continuous quantum phase transitions between those phases.

  13. Electronic structure of the two-legged ladder compound La 1-xSr xCuO 2.5 (United States)

    Mattheiss, L. F.


    The band properties of La 1-xSr xCuO 2.5, an orthorhombic cuprate that contains a pair of nearly orthogonal two-legged ladders and undergoes an insulator-metal transition near x ≈ 0.2, have been calculated using the linear augmented-plane-wave method. The undoped x = 0 results feature four half-filled σ ∗ bands that exhibit anisotropic (i.e., {v∥}/{v⊥} ≈ 4 ) rather than one-dimensional (1D) characteristics near E F. A tight-binding analysis shows that, for ladders in the x-y plane, the σ ∗ bands at E F reflect a ˜50-50 O(2p)Cu(3d) admixture, with d(x 2-y 2) orbitals dominating (˜75%) the 3d fraction, but containing sufficient d(yz) - d(3z 3-r 2) hybridization (˜12%+12%) to wash out most 1D features via interladder coupling.

  14. Ground-state phase diagram, fermionic entanglement and kinetically-induced frustration in a hybrid ladder with localized spins and mobile electrons (United States)

    Carvalho, R. C. P.; Pereira, M. S. S.; de Oliveira, I. N.; Strečka, J.; Lyra, M. L.


    We introduce an exactly solvable hybrid spin-ladder model containing localized nodal Ising spins and interstitial mobile electrons, which are allowed to perform a quantum-mechanical hopping between the ladder’s legs. The quantum-mechanical hopping process induces an antiferromagnetic coupling between the ladder’s legs that competes with a direct exchange coupling of the nodal spins. The model is exactly mapped onto the Ising spin ladder with temperature-dependent two- and four-spin interactions, which is subsequently solved using the transfer-matrix technique. We report the ground-state phase diagram and compute the fermionic concurrence to characterize the quantum entanglement between the pair of interstitial mobile electrons. We further provide a detailed analysis of the local spin ordering including the pair and four-spin correlation functions around an elementary plaquette, as well as, the local ordering diagrams. It is shown that a complex sequence of distinct local orderings and frustrated correlations takes place when the model parameters drive the investigated system close to a zero-temperature triple coexistence point.

  15. Radiologic Career Ladder (United States)


    of operating fixed and mobile radiologic equipment; routine and special radiographic positioning; theory and practice of special radiographic...defined as training provided by resident technical schools, field training detachments (FTD), mobile training teams (MTT), formal OJT, or any other...TISSUE STUDIES 81 1316 PERFORM HUMERUS RADIOGRAPHIC EXAMINATIONS 81 1306 PERFORM COCCYX RADIOGRAPHIC EXAMINATIONS 81 1329 PERFORM PARANASAL SINUS

  16. Subsistence Operations Career Ladder. (United States)



  17. National Wind Distance Learning Collaborative

    Energy Technology Data Exchange (ETDEWEB)

    Dr. James B. Beddow


    Executive Summary The energy development assumptions identified in the Department of Energy's position paper, 20% Wind Energy by 2030, projected an exploding demand for wind energy-related workforce development. These primary assumptions drove a secondary set of assumptions that early stage wind industry workforce development and training paradigms would need to undergo significant change if the workforce needs were to be met. The current training practice and culture within the wind industry is driven by a relatively small number of experts with deep field experience and knowledge. The current training methodology is dominated by face-to-face, classroom based, instructor present training. Given these assumptions and learning paradigms, the purpose of the National Wind Distance Learning Collaborative was to determine the feasibility of developing online learning strategies and products focused on training wind technicians. The initial project scope centered on (1) identifying resources that would be needed for development of subject matter and course design/delivery strategies for industry-based (non-academic) training, and (2) development of an appropriate Learning Management System (LMS). As the project unfolded, the initial scope was expanded to include development of learning products and the addition of an academic-based training partner. The core partners included two training entities, industry-based Airstreams Renewables and academic-based Lake Area Technical Institute. A third partner, Vision Video Interactive, Inc. provided technology-based learning platforms (hardware and software). The revised scope yielded an expanded set of results beyond the initial expectation. Eight learning modules were developed for the industry-based Electrical Safety course. These modules were subsequently redesigned and repurposed for test application in an academic setting. Software and hardware developments during the project's timeframe enabled redesign providing

  18. Language Distance Learning for the Digital Generation (United States)

    Duran-Cerda, Dolores


    The purpose of this article was to shed light on the potential of distance learning to overcome challenges in distance, space, time, and human and economic resources that limit access to language learning opportunities in cultural, literary, historical, geographical, and cross-cultural frames. Language and literature educators collectively have…

  19. A History of Distance Education in Mexico (United States)

    Castaneda, Manuel Moreno


    Research on distance education in Mexico is still in the embryonic stage, in spite of its long history. One indication is that among the lines of research defined by the Mexican Council on Educational Research, the leading organization in the field in Mexico, distance education does not even appear. Only recently, in the last few years, has an…

  20. Investigating Distance Education Students' Study Skills (United States)

    Poyraz, Cengiz


    Distance education, which is a planned way of teaching in which students and instructors are brought face to face in a classroom environment in several different ways by means of technology, has started to become widespread in many fields today. In distance education, students and instructors reside in different locations. Students can learn at…

  1. Distance Education Report, 2011-2012 (United States)

    California Community Colleges, Chancellor's Office, 2013


    This is a report on distance education in the California Community College. This is the seventh report to the California Community Colleges Board of Governors (BOG) per BOG Standing Order 409 (b) "that evaluates the effectiveness of distance education and education technology system wide and provides analysis of data demographically (by age,…

  2. 49 CFR 176.708 - Segregation distances. (United States)


    ... 49 Transportation 2 2010-10-01 2010-10-01 false Segregation distances. 176.708 Section 176.708... Requirements for Radioactive Materials § 176.708 Segregation distances. (a) Table IV lists minimum separation... into account any relocation of cargo during the voyage. (e) Any departure from the segregation...

  3. Is Distance Education a Faustian Bargain? (United States)

    DiBiase, David


    Focuses on the morality of distance education in geography. States that distance education learners are a qualitatively different, older population with educational needs separate from traditional on-campus students. Argues that geography educators have a moral obligation to serve lifelong learners. Includes references. (CMK)

  4. Getting Started as Distance Learning Librarian (United States)

    Wyss, Paul Alan


    Many colleges and universities are developing distance education options for their current and future students. Library support is vital to the success of this clientele. Academic libraries that do not have Distance Learning Librarians will have to create these types of positions. This article illustrates the experience of one librarian in…

  5. Distance Learning for Mobile Internet Users (United States)

    Necat, Beran


    This paper provides an overview on the current state of art in the field of Distance learning for mobile users. It mentions a large range of technologies, services and approaches that may be used to bring distance learning to mobile internet users. These technologies are supposed to considerably increase innovative e-learning solutions for the…

  6. Exploring Cloud Computing for Distance Learning (United States)

    He, Wu; Cernusca, Dan; Abdous, M'hammed


    The use of distance courses in learning is growing exponentially. To better support faculty and students for teaching and learning, distance learning programs need to constantly innovate and optimize their IT infrastructures. The new IT paradigm called "cloud computing" has the potential to transform the way that IT resources are utilized and…

  7. Who Graduates from Irish Distance University Education? (United States)

    Delaney, Lorraine


    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…

  8. Applying Leadership Theories to Distance Education Leadership (United States)

    Nworie, John


    The instructional delivery mode in distance education has been transitioning from the context of a physical classroom environment to a virtual learning environment or maintaining a hybrid of the two. However, most distance education programs in dual mode institutions are situated in traditional face-to-face instructional settings. Distance…

  9. Distance Education for People with Visual Impairments (United States)

    Liakou, Maria; Manousou, Evaggelia


    This paper studies the standards of higher Distance Education, focusing on the Hellenic Open University, for people who have visual impairments, so that it becomes fully accessible and thus helps reduce social exclusion. Specifically, it aims to study the operational context of Distance Education, the possibilities that modern technology provides…

  10. Distance dependence of fluorescence resonance energy transfer

    Indian Academy of Sciences (India)

    Deviations from the usual -6 dependence of the rate of fluorescence resonance energy transfer (FRET) on the distance between the donor and the acceptor have been a common scenario in the recent times. In this paper, we present a critical analysis of the distance dependence of FRET, and try to illustrate the non--6 ...

  11. When Do Distance Effects Become Empirically Observable?

    DEFF Research Database (Denmark)

    Beugelsdijk, Sjoerd; Nell, Phillip C.; Ambos, Björn


    , on average, distance is unrelated to value added by headquarters but that this effect is contingent upon the extent to which the subsidiary is locally embedded. Only after a certain threshold level of subsidiary embeddedness, distance is negatively related to headquarters value added. This effect is more...

  12. Distance Learners‟ Perception of Learner Support Services ...

    African Journals Online (AJOL)

    The University of Education, Winneba (UEW), produces self instructional materials for its distance education students and in addition provides some learner support services. The study investigated UEW Distance Education (DE) students‟ perceived satisfaction with learner support services available to them. The study ...

  13. Genetic distances based on quantitative traits. (United States)

    Camussi, A; Ottaviano, E; Calinski, T; Kaczmarek, Z


    Morphological data showing continuous distributions, polygenically controlled, may be particularly useful in intergroup classification below the species level; an appropriate distance analysis based on these traits is an important tool in evolutionary biology and in plant and animal breeding.--The interpretation of morphological distances in genetic terms is not easy because simple phenotypic data may lead to biased estimates of genetic distances. Convenient estimates can be obtained whenever it is possible to breed populations according to a suitable crossing design and to derive information from genetic parameters.--A general method for determining genetic distances is proposed. The procedure of multivariate analysis of variance is extended to estimate appropriate genetic parameters (genetic effects). Not only are optimal statistical estimates of parameters obtained but also the procedure allows the measurement of genetic distances between populations as linear functions of the estimated parameters, providing an appropriate distance matrix that can be defined in terms of these parameters. The use of the T2 statistic, defined in terms of the vector of contrasts specifying the distance, permits the testing of the significance of any distance between any pair of populations that may be of interest from a genetic point of view.--A numerical example from maize diallel data is reported in order to illustrate the procedure. In particular, heterosis effects are used as the basis for estimates of genetic divergence between populations.

  14. Digital Competence Model of Distance Learning Students (United States)

    da Silva, Ketia Kellen A.; Behar, Patricia A.


    This article presents the development of a digital competency model of Distance Learning (DL) students in Brazil called CompDigAl_EAD. The following topics were addressed in this study: Educational Competences, Digital Competences, and Distance Learning students. The model was developed between 2015 and 2016 and is being validated in 2017. It was…

  15. Sensor Network Localization with Imprecise Distances

    NARCIS (Netherlands)

    Cao, M.; Morse, A.S.; Anderson, B.D.O.


    An approach to formulate geometric relations among distances between nodes as equality constraints is introduced in this paper to study the localization problem with imprecise distance information in sensor networks. These constraints can be further used to formulate optimization problems for

  16. Three Generations of Distance Education Pedagogy (United States)

    Anderson, Terry; Dron, Jon


    This paper defines and examines three generations of distance education pedagogy. Unlike earlier classifications of distance education based on the technology used, this analysis focuses on the pedagogy that defines the learning experiences encapsulated in the learning design. The three generations of cognitive-behaviourist, social constructivist,…

  17. anthropomethric studies of the interpupillary distance among

    African Journals Online (AJOL)



    Jun 1, 2012 ... The objective of the study is to establish standards for the Near Inter pupilliary distance (NIPD) ... Interpupillary distance (IPD) has been defined by .... Mean, standard deviation, and independent sample t test were used for evaluating the difference between males and females. All the measurements were ...

  18. New Strategy of the Distance Education (United States)

    Bunyatova, Fatma Khanim; Salamov, Gulbala


    This article is dedicated to new strategy of distance education. The article deals with the possibilities of ICT (Information and Communication Technologies) in teaching specially distance education. In the article, ICT technological tools and their methods of application in educational process are looked over; discrepancy of intellectual…

  19. Distance Learning Delivery Systems: Instructional Options. (United States)

    Steele, Ray L.


    Discusses the availability of satellite and cable programing to provide distance education opportunities in school districts. Various delivery systems are described, including telephones with speakers, personal computers, and satellite dishes; and a sidebar provides a directory of distance learning opportunities, including telecommunications…

  20. Distance Synchronous Information Systems Course Delivery (United States)

    Peslak, Alan R.; Lewis, Griffith R.; Aebli, Fred


    Teaching computer information systems via distance education is a challenge for both student and faculty. Much research work has been performed on methods of teaching via distance education. Today we are faced with a variety of options for course delivery. Asynchronous delivery via online or lesson instruction still remains most common. But…

  1. Distance Education Technologies in Asia | IDRC - International ...

    International Development Research Centre (IDRC) Digital Library (Canada)


    Nov 10, 2010 ... For observers elsewhere in the world, the most striking feature of distance education (DE) in Asia is the mega-universities and mega-schools that have added many millions to the global tally of distance learners in recent decades. These are institutions such as China's radio and television universities (now ...

  2. NASA Langley/CNU Distance Learning Programs. (United States)

    Caton, Randall; Pinelli, Thomas E.

    NASA Langley Research Center and Christopher Newport University (CNU) provide, free to the public, distance learning programs that focus on math, science, and/or technology over a spectrum of education levels from K-adult. The effort started in 1997, and currently there are a suite of five distance-learning programs. This paper presents the major…

  3. On 3-Chromatic Distance-Regular Graphs

    NARCIS (Netherlands)

    Blokhuis, A.; Brouwer, A.E.; Haemers, W.H.


    We give some necessary conditions for a graph to be 3-chromatic in terms of the spectrum of the adjacency matrix.For all known distance-regular graphs it is determined whether they are 3-chromatic.A start is made with the classification of 3-chromatic distance-regular graphs, and it is shown that

  4. Distance Sensitive Bloom Filters Without False Negatives

    DEFF Research Database (Denmark)

    Goswami, Mayank; Pagh, Rasmus; Silvestri, Francesco


    answers. Absence of false negatives is of critical importance in many applications of Bloom filters, so it is natural to ask if this can be also achieved in the distance sensitive setting. Our main contributions are upper and lower bounds (that are tight in several cases) for space usage in the distance...

  5. Three Generations of Distance Education Pedagogy

    Directory of Open Access Journals (Sweden)

    Terry Anderson


    Full Text Available This paper defines and examines three generations of distance education pedagogy. Unlike earlier classifications of distance education based on the technology used, this analysis focuses on the pedagogy that defines the learning experiences encapsulated in the learning design. The three generations of cognitive-behaviourist, social constructivist, and connectivist pedagogy are examined, using the familiar community of inquiry model (Garrison, Anderson, & Archer, 2000 with its focus on social, cognitive, and teaching presences. Although this typology of pedagogies could also be usefully applied to campus-based education, the need for and practice of openness and explicitness in distance education content and process makes the work especially relevant to distance education designers, teachers, and developers. The article concludes that high-quality distance education exploits all three generations as determined by the learning content, context, and learning expectations.

  6. Ethnical distance in Vojvodina: Research results

    Directory of Open Access Journals (Sweden)

    Lazar Žolt


    Full Text Available This article presents the results of the ethnical distance measuring in Vojvodina, the north Province of the Republic of Serbia. The measuring was carried out on autumn 2002, during realization of the wider project of multiculturalism research in the mentioned region. According to the results the ethnical distances in Vojvodina are quite equalized and they are grouped around the attitude "all the same". Vojvodinian Serbs are more favorable partners for the majority of social contacts, and the relatively largest distance is shown toward Roma. The ethnical distance results also discovers two very important factors for understanding the interethnic relations in Vojvodina: first, the "rational" kind of social contacts with the members of the other ethnical groups are more preferable for the majority of respondents, and second, they have very equal distances toward their own ethnical groups.

  7. Distancing from experienced self: how global-versus-local perception affects estimation of psychological distance. (United States)

    Liberman, Nira; Förster, Jens


    In 4 studies, the authors examined the prediction derived from construal level theory (CLT) that higher level of perceptual construal would enhance estimated egocentric psychological distance. The authors primed participants with global perception, local perception, or both (the control condition). Relative to the control condition, global processing made participants estimate larger psychological distances in time (Study 1), space (Study 2), social distance (Study 3), and hypotheticality (Study 4). Local processing had the opposite effect. Consistent with CLT, all studies show that the effect of global-versus-local processing did emerge when participants estimated egocentric distances, which are distances from the experienced self in the here and now, but did not emerge with temporal distances not from now (Study 1), spatial distances not from here (Study 2), social distances not from the self (Study 3), or hypothetical events that did not involve altering an experienced reality (Study 4).

  8. On Properties of the Generalized Wasserstein Distance (United States)

    Piccoli, Benedetto; Rossi, Francesco


    The Wasserstein distances W p ( p {≥q} 1), defined in terms of a solution to the Monge-Kantorovich problem, are known to be a useful tool to investigate transport equations. In particular, the Benamou-Brenier formula characterizes the square of the Wasserstein distance W 2 as the infimum of the kinetic energy, or action functional, of all vector fields transporting one measure to the other. Another important property of the Wasserstein distances is the Kantorovich-Rubinstein duality, stating the equality between the distance W 1( μ, ν) of two probability measures μ, ν and the supremum of the integrals in d( μ - ν) of Lipschitz continuous functions with Lipschitz constant bounded by one. An intrinsic limitation of Wasserstein distances is the fact that they are defined only between measures having the same mass. To overcome such a limitation, we recently introduced the generalized Wasserstein distances {W_p^{a,b}}, defined in terms of both the classical Wasserstein distance W p and the total variation (or L 1) distance, see (Piccoli and Rossi in Archive for Rational Mechanics and Analysis 211(1):335-358, 2014). Here p plays the same role as for the classic Wasserstein distance, while a and b are weights for the transport and the total variation term. In this paper we prove two important properties of the generalized Wasserstein distances: (1) a generalized Benamou-Brenier formula providing the equality between {W_2^{a,b}} and the supremum of an action functional, which includes a transport term (kinetic energy) and a source term; (2) a duality à la Kantorovich-Rubinstein establishing the equality between {W_1^{1,1}} and the flat metric.

  9. Managing Distance Education Institutions through Value Chain Analysis: the Nigerian Experience. (United States)

    Aderinto, J. A.; Akintayo, M. O.

    Value chain analysis can gauge, analyze, and predict organization effects to control cost in light of achieving strategic organization objectives of distance education. Value chain analysis enables organizations to accomplish their goal or mission through cost effectiveness or differentiation. The value chain activity structure in a distance…

  10. Stress Fracture of the Pubic Ramus in a Female Long Distance Runner: A Case Report

    Directory of Open Access Journals (Sweden)

    Seçkin Şenışık


    Stress fractures of the pelvis should be included in the differential diagnosis of female distance runners who have prolonged groin pain increasing with exercise. Detailed medical history, physical examination, blood tests, and radiological images are keys to reach certain diagnosis. Treatment plan should include risk factor analysis and progressive training programs.

  11. Modern Geometric Methods of Distance Determination (United States)

    Thévenin, Frédéric; Falanga, Maurizio; Kuo, Cheng Yu; Pietrzyński, Grzegorz; Yamaguchi, Masaki


    Building a 3D picture of the Universe at any distance is one of the major challenges in astronomy, from the nearby Solar System to distant Quasars and galaxies. This goal has forced astronomers to develop techniques to estimate or to measure the distance of point sources on the sky. While most distance estimates used since the beginning of the 20th century are based on our understanding of the physics of objects of the Universe: stars, galaxies, QSOs, the direct measures of distances are based on the geometric methods as developed in ancient Greece: the parallax, which has been applied to stars for the first time in the mid-19th century. In this review, different techniques of geometrical astrometry applied to various stellar and cosmological (Megamaser) objects are presented. They consist in parallax measurements from ground based equipment or from space missions, but also in the study of binary stars or, as we shall see, of binary systems in distant extragalactic sources using radio telescopes. The Gaia mission will be presented in the context of stellar physics and galactic structure, because this key space mission in astronomy will bring a breakthrough in our understanding of stars, galaxies and the Universe in their nature and evolution with time. Measuring the distance to a star is the starting point for an unbiased description of its physics and the estimate of its fundamental parameters like its age. Applying these studies to candles such as the Cepheids will impact our large distance studies and calibration of other candles. The text is constructed as follows: introducing the parallax concept and measurement, we shall present briefly the Gaia satellite which will be the future base catalogue of stellar astronomy in the near future. Cepheids will be discussed just after to demonstrate the state of the art in distance measurements in the Universe with these variable stars, with the objective of 1% of error in distances that could be applied to our closest

  12. Has Distance Learning Become More Flexible? Reflections of a Distance Learning Student (United States)

    Thomas, Theda


    This paper provides insight into the way in which distance learning had changed over the past 30 years from the perspective of the author as a distance learning student. The question is then asked as to whether current practice is reducing flexibility for distance learning students? The paper starts with a discussion of flexible learning and the…

  13. The C Terminus of the Core β-Ladder Domain in Japanese Encephalitis Virus Nonstructural Protein 1 Is Flexible for Accommodation of Heterologous Epitope Fusion. (United States)

    Yen, Li-Chen; Liao, Jia-Teh; Lee, Hwei-Jen; Chou, Wei-Yuan; Chen, Chun-Wei; Lin, Yi-Ling; Liao, Ching-Len


    NS1 is the only nonstructural protein that enters the lumen of the endoplasmic reticulum (ER), where NS1 is glycosylated, forms a dimer, and is subsequently secreted during flavivirus replication as dimers or hexamers, which appear to be highly immunogenic to the infected host, as protective immunity can be elicited against homologous flavivirus infections. Here, by using a trans-complementation assay, we identified the C-terminal end of NS1 derived from Japanese encephalitis virus (JEV), which was more flexible than other regions in terms of housing foreign epitopes without a significant impact on virus replication. This mapped flexible region is located in the conserved tip of the core β-ladder domain of the multimeric NS1 structure and is also known to contain certain linear epitopes, readily triggering specific antibody responses from the host. Despite becoming attenuated, recombinant JEV with insertion of a neutralizing epitope derived from enterovirus 71 (EV71) into the C-terminal end of NS1 not only could be normally released from infected cells, but also induced dual protective immunity for the host to counteract lethal challenge with either JEV or EV71 in neonatal mice. These results indicated that the secreted multimeric NS1 of flaviviruses may serve as a natural protein carrier to render epitopes of interest more immunogenic in the C terminus of the core β-ladder domain. The positive-sense RNA genomes of mosquito-borne flaviviruses appear to be flexible in terms of accommodating extra insertions of short heterologous antigens into their virus genes. Here, we illustrate that the newly identified C terminus of the core β-ladder domain in NS1 could be readily inserted into entities such as EV71 epitopes, and the resulting NS1-epitope fusion proteins appeared to maintain normal virus replication, secretion ability, and multimeric formation from infected cells. Nonetheless, such an insertion attenuated the recombinant JEV in mice, despite having retained


    Directory of Open Access Journals (Sweden)

    Glenn RUSSELL


    Full Text Available ABSTRACT Consideration of the place of theory in distance education suggests that existing definitions do not adequately account for economic, cultural and historical factors. The application of the notion of hegemonic valency to distance education highlights the ways in which tools, technological systems and online environments operate in predictable ways. Historically, the imperatives of market forces and social justice have displayed a tension that is continued in contemporary contexts including virtual learning environments. A characteristic of this tension can be seen in the forces and interactions associated with globalisation and technology. These forces, in association with others, have contributed to a null curriculum in which some alternatives open to distance education practitioners remain invisible. It is likely that this situation is further compounded by the difficulty of ascertaining what distance education practices are actually operating world-wide at any identifiable time. Available options for distance educators can be understood in terms of instrumental and interpersonal axes that can potentially indicate the relative consideration that can be given to these factors. This approach is suggested as one way to understand available options at a time when there has been an apparent increase in instrumental approaches to distance education at the expense of interpersonal approaches and issues of social justice. While this problem is of concern, it is more appropriate to reflect on the unintended consequences of distance education for society and identify them than it is to uncritically oppose globalisation and its adherents.

  15. The psychological distance of climate change. (United States)

    Spence, Alexa; Poortinga, Wouter; Pidgeon, Nick


    Avoiding dangerous climate change is one of the most urgent social risk issues we face today and understanding related public perceptions is critical to engaging the public with the major societal transformations required to combat climate change. Analyses of public perceptions have indicated that climate change is perceived as distant on a number of different dimensions. However, to date there has been no in-depth exploration of the psychological distance of climate change. This study uses a nationally representative British sample in order to systematically explore and characterize each of the four theorized dimensions of psychological distance--temporal, social, and geographical distance, and uncertainty--in relation to climate change. We examine how each of these different aspects of psychological distance relate to each other as well as to concerns about climate change and sustainable behavior intentions. Results indicate that climate change is both psychologically distant and proximal in relation to different dimensions. Lower psychological distance was generally associated with higher levels of concern, although perceived impacts on developing countries, as an indicator of social distance, was also significantly related to preparedness to act on climate change. Our findings clearly point to the utility of risk communication techniques designed to reduce psychological distance. However, highlighting the potentially very serious distant impacts of climate change may also be useful in promoting sustainable behavior, even among those already concerned. © 2011 Society for Risk Analysis.

  16. Environmental Impact of Long Distance Travel

    DEFF Research Database (Denmark)

    Christensen, Linda


    This paper presents an analysis of the CO2 emission resulting from long distance travel by Danes. The emissions are analysed as the Danes’ footprint the whole way from Denmark to the final destination. International travel represents 31% of the Danes’ CO2 emission from passenger travel...... and the climate burden from long overseas distances is especially high even though only few travel overseas. The travel activity is furthermore increasing much more for long distances than for European destinations. Domestic travel activity with overnight stay is nearly stagnating. The study furthermore shows...

  17. Environmental Impact of Long Distance Travel

    DEFF Research Database (Denmark)

    Christensen, Linda

    This paper presents an analysis of the CO2 emission resulting from long distance travel by Danes. The emissions are analysed as the Danes’ footprint the whole way from Denmark to the final destination. International travel represents 31% of the Danes’ CO2 emission from passenger travel...... and the climate burden from long overseas distances is especially high even though only few travel overseas. The travel activity is furthermore increasing much more for long distances than for European destinations. Domestic travel activity with overnight stay is nearly stagnating. The study furthermore shows...

  18. New Concepts in Fish Ladder Design, Volume III of IV, Assessment of Fishway Development and Design, 1982-1983 Final Report.

    Energy Technology Data Exchange (ETDEWEB)

    Powers, Patrick D.; Orsborn, John F.


    This volume covers the broad, though relatively short, historical basis for this project. The historical developments of certain design features, criteria and research activities are traced. Current design practices are summarized based on the results of an international survey and interviews with agency personnel and consultants. The fluid mechanics and hydraulics of fishway systems are discussed. Fishways (or fishpasses) can be classified in two ways: (1) on the basis of the method of water control (chutes, steps (ladders), or slots); and (2) on the basis of the degree and type of water control. This degree of control ranges from a natural waterfall to a totally artificial environment at a hatchery. Systematic procedures for analyzing fishways based on their configuration, species, and hydraulics are presented. Discussions of fish capabilities, energy expenditure, attraction flow, stress and other factors are included.

  19. Double-resonance optical-pumping effect and ladder-type electromagnetically induced transparency signal without Doppler background in cesium atomic vapour cell

    International Nuclear Information System (INIS)

    Yang Bao-Dong; Gao Jing; Liang Qiang-Bing; Wang Jie; Zhang Tian-Cai; Wang Jun-Min


    In a Doppler-broadened ladder-type cesium atomic system (6S 1/2 -6P 3/2 -8S 1/2 ), this paper characterizes electromagnetically induced transparency (EIT) in two different experimental arrangements, and investigates the influence of the double-resonance optical-pumping (DROP) effect on EIT in both arrangements. When the probe laser is weak, DROP is explicitly suppressed. When the probe laser is moderate, population of the intermediate level (6P 3/2 F' = 5) is remarkable, therefore DROP is mixed with EIT. An interesting bimodal spectrum with the broad component due to DROP and the narrow part due to EIT has been clearly observed in cesium 6S 1/2 F = 4−6P 3/2 F' = 5−8S 1/2 F″ = 4 transitions. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  20. Highly Efficient Inverted D:A1:A2Ternary Blend Organic Photovoltaics Combining a Ladder-type Non-Fullerene Acceptor and a Fullerene Acceptor. (United States)

    Chang, Shao-Ling; Cao, Fong-Yi; Huang, Wen-Chia; Huang, Po-Kai; Hsu, Chain-Shu; Cheng, Yen-Ju


    A formylated benzodi(cyclopentadithiophene) (BDCPDT) ladder-type structure with forced coplanarity is coupled with two 1,1-dicyanomethylene-3-indanone (IC) moieties via olefination to form a non-fullerene acceptor, BDCPDT-IC. The BDCPDT-IC, as an acceptor (A 1 ) with broad light-absorbing ability and excellent solution processability, is combined with a second PC 71 BM acceptor (A 2 ) and a medium band gap polymer, PBDB-T, as the donor (D) to form a ternary blend with gradient HOMO/LUMO energy alignments and panchromatic absorption. The device with the inverted architecture using the D:A 1 :A 2 ternary blend has achieved a highest efficiency of 9.79% with a superior J sc of 16.84 mA cm -2 .

  1. An Approach to Evaluating Distance Learning Events

    National Research Council Canada - National Science Library

    Wisher, Robert


    In accordance with an agreement with the National Guard Bureau (NGB) a simplified evaluation form was developed that assessed demographic, instructional, and technology factors for distance learning training events of short duration...

  2. Long distance travel ‘today’

    DEFF Research Database (Denmark)

    Christensen, Linda


    This paper presents an overview of the Dane’s long distance travel. It is a part of the Drivers and Limits project about long distance travel. Long distance travel is in the project defined as infrequent travel with overnight stay. Danes 15-85 years-old travel in average 5.5 long distance travel...... per year og which a third is for international destinations, a third is for domestic second homes and a third are other domestic trips. However, 87% of the kilometres are for international destinations and only 4% are for domestic second homes. Travel activity is very uneven distributed with only half...... of the population having had a journey during the last three month. At the other hand 60% have travelled internationally during the last year and only 2% have never travelled abroad. The paper presents among other things how the travel activity is distributed on travel purpose and mode and how the mode choice...

  3. Applying Technology to Marine Corps Distance Learning

    National Research Council Canada - National Science Library

    Broihier, Michael


    The purpose of this thesis is to investigate the application of technology to distance learning with the intention of recommending to the Marine Corps a feasible migration path away from its current...

  4. Project Work in Networked Distance Education

    DEFF Research Database (Denmark)

    Knudsen, Morten; Helbo, Jan; Jensen, Lars Peter


    -study, whereas the project study form is based on collaboration and dialogue. Consequently, successful implementation of project work in distance education requires extensive utilisation of new information and communication technology. In this paper the experiences of project work in a new Master of Industrial....... As the experience since then has proven this to be a very successful innovation in higher education [1], it seems to be an obvious idea also to base our new distance educations on the project study form. Traditionally, however, distance education has been characterized by one-way communication and self...... Information Technology distance education is described. The program is offered through Open University, and the students have a BSc degree or equivalent and at least 2 years of relevant professional experience - and a full-time job. The students are assumed to study 20 hours per week, half of the time being...

  5. Research in Distance Education: A Status Report

    Directory of Open Access Journals (Sweden)

    Farhad Saba


    Full Text Available Since the 1950s and expansion of social science research, distance education has been studied in comparison to face-to-face or classroom instruction. Although researchers continue to conduct comparative studies, their usefulness in revealing more information has diminished over the years; invariably, they have returned a “no significant difference” result between various forms of instruction. In recent years, researchers have moved beyond atheoretical, experimental comparative studies and have introduced new methods, such as discourse analysis, and in-depth interview of learners. These new methods overcome many methodological and theoretical limitations of the physical science view of distance education. These studies have further revealed the complexity of distance education, indicating the many variables involved in the concept. Starting with the core issue of instructional interaction and grounded on the theory of transactional distance, a new strand of research using methods related to systems dynamics, hierarchy and complexity theories, promises a more comprehensive understanding.

  6. Physical Distance and Attraction: An Intensification Effect (United States)

    Schiffenbauer, Allen; Schiavo, R. Steven


    This study was designed to test the effects of both interaction distance and the quality of the interaction upon attraction. The implications of this research for studies concerning crowding is discussed, as are possible explanatory mechanisms. (Editor/RK)

  7. Retarded distances and the Doppler effect

    International Nuclear Information System (INIS)

    Strel'tsov, V.N.


    A relativistic transformation of the retarded distance is presented. Arguments of general nature in favour of the concept of the relativistic (radar) length leading to this formula are presented. 10 refs

  8. Managing information resources for distance education | Lawoe ...

    African Journals Online (AJOL)

    secondary/tertiary education. Effective management of library/information services in support of distance education ensures a higher level of success in the programme. The traditional methods of library and information provision are discussed ...

  9. Institutional Distance and the Internationalization Process

    DEFF Research Database (Denmark)

    Pogrebnyakov, Nicolai; Maitland, Carleen


    This paper applies the institutional lens to the internationalization process model. It updates the concept of psychic distance in the model with a recently developed, theoretically grounded construct of institutional distance. Institutions are considered simultaneously at the national and indust...... used in the internationalization process research. The results also indicate that the internationalization behavior of this type of service firms might differ from the staged process predicted by the internationalization process model....... levels. It also aims to understand whether the internationalization process of service firms is different from the behavior predicted by the model, which was developed for the manufacturing context. We empirically test the model using proportional hazard analysis with 130 instances of entry and presence......This paper applies the institutional lens to the internationalization process model. It updates the concept of psychic distance in the model with a recently developed, theoretically grounded construct of institutional distance. Institutions are considered simultaneously at the national and industry...

  10. FAQS. III: Groupwork in Distance Learning. (United States)

    Felder, Richard M.; Brent, Rebecca


    Offers ideas for getting students at remote sites to collaborate when attending lectures in a synchronous course, working through lessons in an asynchronous course, and doing homework in either distance mode. (ASK)

  11. Short-distance structure of instantons

    International Nuclear Information System (INIS)

    Carlitz, R.D.; Creamer, D.B.

    The short distance structure of a quark propagator in an instanton background field is analyzed. This analysis describes the influence of instantons upon physical processes such as electron-position annihilation and the deep inelastic scattering of leptons from hadrons

  12. Designing legible fonts for distance reading

    DEFF Research Database (Denmark)

    Beier, Sofie


    This chapter reviews existing knowledge on distance legibility of fonts, and finds that for optimal distance reading, letters and numbers benefit from relative wide shapes, open inner counters and a large x-height; fonts should further be widely spaced, and the weight should not be too heavy or t...... light. Research also indicates that serifs on the vertical extremes improve legibility under such reading conditions.......This chapter reviews existing knowledge on distance legibility of fonts, and finds that for optimal distance reading, letters and numbers benefit from relative wide shapes, open inner counters and a large x-height; fonts should further be widely spaced, and the weight should not be too heavy or too...

  13. Reliability of reference distances used in photogrammetry. (United States)

    Aksu, Muge; Kaya, Demet; Kocadereli, Ilken


    To determine the reliability of the reference distances used for photogrammetric assessment. The sample consisted of 100 subjects with mean ages of 22.97 +/- 2.98 years. Five lateral and four frontal parameters were measured directly on the subjects' faces. For photogrammetric assessment, two reference distances for the profile view and three reference distances for the frontal view were established. Standardized photographs were taken and all the parameters that had been measured directly on the face were measured on the photographs. The reliability of the reference distances was checked by comparing direct and indirect values of the parameters obtained from the subjects' faces and photographs. Repeated measure analysis of variance (ANOVA) and Bland-Altman analyses were used for statistical assessment. For profile measurements, the indirect values measured were statistically different from the direct values except for Sn-Sto in male subjects and Prn-Sn and Sn-Sto in female subjects. The indirect values of Prn-Sn and Sn-Sto were reliable in both sexes. The poorest results were obtained in the indirect values of the N-Sn parameter for female subjects and the Sn-Me parameter for male subjects according to the Sa-Sba reference distance. For frontal measurements, the indirect values were statistically different from the direct values in both sexes except for one in male subjects. The indirect values measured were not statistically different from the direct values for Go-Go. The indirect values of Ch-Ch were reliable in male subjects. The poorest results were obtained according to the P-P reference distance. For profile assessment, the T-Ex reference distance was reliable for Prn-Sn and Sn-Sto in both sexes. For frontal assessment, Ex-Ex and En-En reference distances were reliable for Ch-Ch in male subjects.

  14. Distances on a lattice from noncommutative geometry

    International Nuclear Information System (INIS)

    Bimonte, G.; Lizzi, F.; Sparano, G.


    Using the tools of noncommutative geometry we calculate the distances between the points of a lattice on which the usual discretized Dirac operator has been defined. We find that these distances do not have the expected behaviour, revealing that from the metric point of view the lattice does not look at all as a set of points sitting on the continuum manifold. We thus have an additional criterion for the choice of the discretization of the Dirac operator. (author). 11 refs, 1 tab

  15. Intimacy, Distance Relationships and Emotional Care


    Holmes, Mary


    The social changes surrounding individualisation and globalization impact upon our emotional and intimate lives. Geographical mobility is especially significant and its effects on relationships much debated. Distance relationships are one example of how people respond to such changes. This paper is based on an ESRC funded qualitative study of couples in distance relationships. The argument is that such forms of loving are not all about self-satisfaction, although they may prompt reflexivity a...

  16. Deriving the Hirshfeld partitioning using distance metrics (United States)

    Heidar-Zadeh, Farnaz; Ayers, Paul W.; Bultinck, Patrick


    The atoms in molecules associated with the Hirshfeld partitioning minimize the generalized Hellinger-Bhattacharya distance to the reference pro-atom densities. Moreover, the reference pro-atoms can be chosen by minimizing the distance between the pro-molecule density and the true molecular density. This provides an alternative to both the heuristic "stockholder" and the mathematical information-theoretic interpretations of the Hirshfeld partitioning. These results extend to any member of the family of f-divergences.

  17. Computational Developments for Distance Determination of Stellar ...

    Indian Academy of Sciences (India)

    In this paper, we consider a statistical method for distance determination of stellar groups. The method depends on the assumption that the members of the group ... The variance–covariance matrix Var(ˆc) of the unbiased estimators ˆc is given by: Var(ˆc) = ˜σ2G. −1 . (3). • The average squared distance between ˆc and c is:.

  18. Globalization, Distance Education and Hegemonic Futures


    RUSSELL, Glenn


    ABSTRACT Consideration of the place of theory in distance education suggests that existing definitions do not adequately account for economic, cultural and historical factors. The application of the notion of hegemonic valency to distance education highlights the ways in which tools, technological systems and online environments operate in predictable ways. Historically, the imperatives of market forces and social justice have displayed a tension that is continued in contemporary contexts inc...

  19. Deriving the Hirshfeld partitioning using distance metrics

    International Nuclear Information System (INIS)

    Heidar-Zadeh, Farnaz; Ayers, Paul W.; Bultinck, Patrick


    The atoms in molecules associated with the Hirshfeld partitioning minimize the generalized Hellinger-Bhattacharya distance to the reference pro-atom densities. Moreover, the reference pro-atoms can be chosen by minimizing the distance between the pro-molecule density and the true molecular density. This provides an alternative to both the heuristic “stockholder” and the mathematical information-theoretic interpretations of the Hirshfeld partitioning. These results extend to any member of the family of f-divergences

  20. Stellar candles for the extragalactic distance scale

    CERN Document Server

    Gieren, Wolfgang


    This volume reviews the current status with respect to both theory and observation of the extragalactic distance scale. A sufficient accuracy is required both for a precise determination of the cosmological parameters and also in order to achieve a better understanding of physical processes in extragalactic systems. The "standard candles", used to set up the extragalactic distance scale, reviewed in this book include cepheid variables, RR Lyrae variables, novae, Type Ia and Type II supernovae as well as globular clusters and planetary nebulae.

  1. Dimensionality Reduction via Euclidean Distance Embeddings


    Šarić, Marin; Ek, Carl Henrik; Kragić, Danica


    This report provides a mathematically thorough review and investigation of Metric Multidimensional scaling (MDS) through the analysis of Euclidean distances in input and output spaces. By combining a geometric approach with modern linear algebra and multivariate analysis, Metric MDS is viewed as a Euclidean distance embedding transformation that converts between coordinate and coordinate-free representations of data. In this work we link Mercer kernel functions, data in infinite-dimensional H...

  2. Soliton surfaces associated with sigma models: differential and algebraic aspects

    International Nuclear Information System (INIS)

    Goldstein, P P; Grundland, A M; Post, S


    In this paper, we consider both differential and algebraic properties of surfaces associated with sigma models. It is shown that surfaces defined by the generalized Weierstrass formula for immersion for solutions of the CP N-1 sigma model with finite action, defined in the Riemann sphere, are themselves solutions of the Euler–Lagrange equations for sigma models. On the other hand, we show that the Euler–Lagrange equations for surfaces immersed in the Lie algebra su(N), with conformal coordinates, that are extremals of the area functional, subject to a fixed polynomial identity, are exactly the Euler–Lagrange equations for sigma models. In addition to these differential constraints, the algebraic constraints, in the form of eigenvalues of the immersion functions, are systematically treated. The spectrum of the immersion functions, for different dimensions of the model, as well as its symmetry properties and its transformation under the action of the ladder operators are discussed. Another approach to the dynamics is given, i.e. description in terms of the unitary matrix which diagonalizes both the immersion functions and the projectors constituting the model. (paper)

  3. Concentrated Differential Privacy


    Dwork, Cynthia; Rothblum, Guy N.


    We introduce Concentrated Differential Privacy, a relaxation of Differential Privacy enjoying better accuracy than both pure differential privacy and its popular "(epsilon,delta)" relaxation without compromising on cumulative privacy loss over multiple computations.

  4. Testing Extinction Distances to Massive Star-Forming Regions Against Maser Parallax Distances (United States)

    Foster, Jonathan B.; Stead, J.; Benjamin, R.; Jackson, J.


    Accurate distances to massive star-forming regions are critical for converting observed values into physical quantities. Recent parallax measurements of masers within massive star-forming regions have established a reliable set of distances to a number of clouds in the first quadrant, ranging from 1 to 6 kpc. Unfortunately, maser parallax measurements are difficult to make and only possible in regions which exhibit bright masers. We report on a study using these distances to validate and calibrate two different near-infrared extinction distance methods which combine a galactic model with UKIDSS/GPS and 2MASS data. One method uses star counts of blue foreground stars, and the other uses red giant stars as standard candles. We also compare the parallax and extinction distances to kinematic distances using a variety of rotation curves. Support for this project provided by a grant from NASA.

  5. Technology Closes the Distance: Global Solutions Show the Variety, Equity, and Accessibility of Distance Learning Options (United States)

    Burns, Mary


    The number of U.S. teachers participating in some form of distance education is on the rise, yet compared to many nations, distance-based professional learning is fairly new in the U.S. What are common elements of effective global distance education for teachers, and what lessons do they hold for those who design similar programs in the U.S.? Over…


    Directory of Open Access Journals (Sweden)

    Yulija Mihajlovna Tsarapkina


    Full Text Available The article is devoted to the actual problem of distance education potential and prospects research in the Russian education system. According to the UNESCO estimates, if the current trend continues, then the number of people with a firm desire to receive an education would increase from 165 millions to 263 millions [7, 12]. Thus 98 million qualified students worldwide will be excluded from higher education due to a shortage of university seats. The purpose of the study is to analyze the historical and present state of the problem, to identify the potential and prospects of the development in distance learning within higher education. The methodological base of the research has become common methods of pedagogical sciences: pedagogical observation, survey, questionnaire, testing, comparative analysis, pedagogical experiment. The analytical review has shown several problem areas within distance learning, such as student’s motivation while distance course learning and training efficiency as compared to full-time university training. Combination of full-time training and distance learning leads to 31% enhancement of training efficiency and shows a sustainable increase of student’s motivation.


    Directory of Open Access Journals (Sweden)

    Cengiz POYRAZ


    Full Text Available Distance education, which is a planned way of teaching in which students and instructors are brought face to face in a classroom environment in several different ways by means of technology, has started to become widespread in many fields today. In distance education, students and instructors reside in different locations. Students can learn at their pace and control their learning path, content and load of what they have learned and evaluate it. However, they should adopt strategies for effective studying in order not to waste their time and efforts. Because study skills, motivation, time management, exam preparation and coping with exam stress have an impact on students’ success. In this context, distance education students’ study skills are foregrounded in today’s widespread use of distance education. In accordance with this, this study aims to investigate some variables which are influential on the dimensions of distance education students’ motivation, time management, exam preparation and coping with exam stress. A personal information form and the Study Skills scale were used for data collection. This study was designed in survey model and SPSS16.0 statistical package program was used for the statistical analyses of the research data. The research findings were discussed in line with the literature and some suggestions were presented for further research and researchers.

  8. A Distance Measure for Genome Phylogenetic Analysis (United States)

    Cao, Minh Duc; Allison, Lloyd; Dix, Trevor

    Phylogenetic analyses of species based on single genes or parts of the genomes are often inconsistent because of factors such as variable rates of evolution and horizontal gene transfer. The availability of more and more sequenced genomes allows phylogeny construction from complete genomes that is less sensitive to such inconsistency. For such long sequences, construction methods like maximum parsimony and maximum likelihood are often not possible due to their intensive computational requirement. Another class of tree construction methods, namely distance-based methods, require a measure of distances between any two genomes. Some measures such as evolutionary edit distance of gene order and gene content are computational expensive or do not perform well when the gene content of the organisms are similar. This study presents an information theoretic measure of genetic distances between genomes based on the biological compression algorithm expert model. We demonstrate that our distance measure can be applied to reconstruct the consensus phylogenetic tree of a number of Plasmodium parasites from their genomes, the statistical bias of which would mislead conventional analysis methods. Our approach is also used to successfully construct a plausible evolutionary tree for the γ-Proteobacteria group whose genomes are known to contain many horizontally transferred genes.

  9. Modeling abundance using hierarchical distance sampling (United States)

    Royle, Andy; Kery, Marc


    In this chapter, we provide an introduction to classical distance sampling ideas for point and line transect data, and for continuous and binned distance data. We introduce the conditional and the full likelihood, and we discuss Bayesian analysis of these models in BUGS using the idea of data augmentation, which we discussed in Chapter 7. We then extend the basic ideas to the problem of hierarchical distance sampling (HDS), where we have multiple point or transect sample units in space (or possibly in time). The benefit of HDS in practice is that it allows us to directly model spatial variation in population size among these sample units. This is a preeminent concern of most field studies that use distance sampling methods, but it is not a problem that has received much attention in the literature. We show how to analyze HDS models in both the unmarked package and in the BUGS language for point and line transects, and for continuous and binned distance data. We provide a case study of HDS applied to a survey of the island scrub-jay on Santa Cruz Island, California.

  10. Universal symbolic expression for radial distance of conic motion

    Directory of Open Access Journals (Sweden)

    Sharaf M.A.


    Full Text Available In the present paper, a universal symbolic expression for radial distance of conic motion in recursive power series form is developed. The importance of this analytical power series representation is that it is invariant under many operations because the result of addition, multiplication, exponentiation, integration, differentiation, etc. of a power series is also a power series. This is the fact that provides excellent flexibility in dealing with analytical, as well as computational developments of problems related to radial distance. For computational developments, a full recursive algorithm is developed for the series coefficients. An efficient method using the continued fraction theory is provided for series evolution, and two devices are proposed to secure the convergence when the time interval (t − t0 is large. In addition, the algorithm does not need the solution of Kepler’s equation and its variants for parabolic and hyperbolic orbits. Numerical applications of the algorithm are given for three orbits of different eccentricities; the results showed that it is accurate for any conic motion.

  11. Testing the Münch hypothesis of long distance phloem transport in plants

    DEFF Research Database (Denmark)

    Knoblauch, Michael; Knoblauch, Jan; Mullendore, Daniel L.


    Long distance transport in plants occurs in sieve tubes of the phloem. The pressure flow hypothesis introduced by Ernst Münch in 1930 describes a mechanism of osmotically generated pressure differentials that are supposed to drive the movement of sugars and other solutes in the phloem......, but this hypothesis has long faced major challenges. The key issue is whether the conductance of sieve tubes, including sieve plate pores, is sufficient to allow pressure flow. We show that with increasing distance between source and sink, sieve tube conductivity and turgor increases dramatically in Ipomoea nil. Our...

  12. Distance statistics in large toroidal maps (United States)

    Guitter, E.


    We compute a number of distance-dependent universal scaling functions characterizing the distance statistics of large maps of genus one. In particular, we obtain explicitly the probability distribution for the length of the shortest non-contractible loop passing via a random point in the map, and that for the distance between two random points. Our results are derived in the context of bipartite toroidal quadrangulations, using their coding by well-labeled 1-trees, which are maps of genus one with a single face and appropriate integer vertex labels. Within this framework, the distributions above are simply obtained as scaling limits of appropriate generating functions for well-labeled 1-trees, all expressible in terms of a small number of basic scaling functions for well-labeled plane trees.

  13. The social distance theory of power. (United States)

    Magee, Joe C; Smith, Pamela K


    We propose that asymmetric dependence between individuals (i.e., power) produces asymmetric social distance, with high-power individuals feeling more distant than low-power individuals. From this insight, we articulate predictions about how power affects (a) social comparison, (b) susceptibility to influence, (c) mental state inference and responsiveness, and (d) emotions. We then explain how high-power individuals' greater experienced social distance leads them to engage in more abstract mental representation. This mediating process of construal level generates predictions about how power affects (a) goal selection and pursuit, (b) attention to desirability and feasibility concerns, (c) subjective certainty, (d) value-behavior correspondence, (e) self-control, and (f) person perception. We also reassess the approach/inhibition theory of power, noting limitations both in what it can predict and in the evidence directly supporting its proposed mechanisms. Finally, we discuss moderators and methodological recommendations for the study of power from a social distance perspective.

  14. Distance 2-Domination in Prisms of Graphs

    Directory of Open Access Journals (Sweden)

    Hurtado Ferran


    Full Text Available A set of vertices D of a graph G is a distance 2-dominating set of G if the distance between each vertex u ∊ (V (G − D and D is at most two. Let γ2(G denote the size of a smallest distance 2-dominating set of G. For any permutation π of the vertex set of G, the prism of G with respect to π is the graph πG obtained from G and a copy G′ of G by joining u ∊ V(G with v′ ∊ V(G′ if and only if v′ = π(u. If γ2(πG = γ2(G for any permutation π of V(G, then G is called a universal γ2-fixer. In this work we characterize the cycles and paths that are universal γ2-fixers.

  15. [Panorama of nursing distance education in Brazil]. (United States)

    Rojo, Priscila Tagliaferro; Vieira, Sheila de Souza; Zem-Mascarenhas, Silvia Helena; Sandor, Elisane Regina; Vieira, Carla Roberta Sola de Paula


    The development of distance education is associated with the popularization and democratization of the accessibility to information and communication technologies. Nursing has been using this modality of education in both undergraduate and graduate courses, which has provided knowledge about other technologies, an easier accessibility, flexibility of time and space, and reduced costs. The objective of this study is map the national higher education distance nursing courses. This exploratory, descriptive study was developed by visiting governmental, non-governmental and institutional websites. Two undergraduate and nine graduate courses in nursing were found, which is considered to be a low number, considering that distance education is an appropriate pedagogical tool that permits to prepare a large number of nurses who are geographically dispersed and who do not have access to the conventional educational processes.

  16. Ethnic and social distance towards Roma population

    Directory of Open Access Journals (Sweden)

    Miladinović Slobodan


    Full Text Available The Roma people are one of social marginalised ethnic groups which can easily be classified as underclass or ethno-class. In this work are presented the results of survey data analysis of ethnic and social distance towards the Roma population (2007. It concludes that the Roma people are one of ethnic groups with the highest social and ethnic distances in all observed social relations. The conclusion is that their generations poverty and still of life which the poverty produces are main causes of the high distance. The society has very important task to overcome situation which keep their social situation. In this paper are showed some of possible solutions of solving global Romas social situation and their integration in the rest of society. .

  17. Contextual Distance Refining for Image Retrieval

    KAUST Repository

    Islam, Almasri


    Recently, a number of methods have been proposed to improve image retrieval accuracy by capturing context information. These methods try to compensate for the fact that a visually less similar image might be more relevant because it depicts the same object. We propose a new quick method for refining any pairwise distance metric, it works by iteratively discovering the object in the image from the most similar images, and then refine the distance metric accordingly. Test show that our technique improves over the state of art in terms of accuracy over the MPEG7 dataset.

  18. Educational mediation in distance education: Brazilian research


    Sousa, Carlos Ângelo de Meneses; Freitas, Lêda Gonçalves de


    The article refers to exploratory research conducted in Capes’ thesis banks, in the Brazilian Digital Library of Thesis and Dissertations, in SciELO Brasil and in Academic Google, on educational mediation in distance education. Two complementary perspectives stood out – the role of the professor-tutor and its relation with technological artifacts. They highlight the importance of educational mediation in distance education processes and point to didactical-educational elements that must be ef...

  19. Markets, Distance Education, and Australian Higher Education

    Directory of Open Access Journals (Sweden)

    Ted Nunan


    Full Text Available The paper argues that the Australian university system is unstable. There will be significant change as government implements its reform agenda and even more radical change if it moves to new deregulation. The role of distance education in university education needs to be analyzed against this ‘market’ agenda of government in terms of characteristics of markets and market behavior. After a scan of the current role, the paper looks at two scenarios (regulated and deregulated for distance education in university teaching and learning in Australia.

  20. Human recognition at a distance in video

    CERN Document Server

    Bhanu, Bir


    Most biometric systems employed for human recognition require physical contact with, or close proximity to, a cooperative subject. Far more challenging is the ability to reliably recognize individuals at a distance, when viewed from an arbitrary angle under real-world environmental conditions. Gait and face data are the two biometrics that can be most easily captured from a distance using a video camera. This comprehensive and logically organized text/reference addresses the fundamental problems associated with gait and face-based human recognition, from color and infrared video data that are