A higher derivative view of the arc length and area actions
Zoller, D.
1991-01-01
Higher derivative versions of the arc length and area actions are presented. The higher derivative theories are equivalent with the corresponding lower derivative theories in absence of interactions. The extra degrees of freedom associated with the higher derivatives are pure gauge due to a hidden reparametrization invariance these theories possess. The extra degrees of freedom are no longer pure gauge in the presence of background fields and the equivalence no longer holds. A string version of Wigner's continuous spin particle is also noted.
A higher derivative view of the arc length and area actions
Zoller, D.
1991-12-31
Higher derivative versions of the arc length and area actions are presented. The higher derivative theories are equivalent with the corresponding lower derivative theories in absence of interactions. The extra degrees of freedom associated with the higher derivatives are pure gauge due to a hidden reparametrization invariance these theories possess. The extra degrees of freedom are no longer pure gauge in the presence of background fields and the equivalence no longer holds. A string version of Wigner`s continuous spin particle is also noted.
Asymptotic vacua with higher derivatives
NASA Astrophysics Data System (ADS)
Cotsakis, Spiros; Kadry, Seifedine; Kolionis, Georgios; Tsokaros, Antonios
2016-04-01
We study limits of vacuum, isotropic universes in the full, effective, four-dimensional theory with higher derivatives. We show that all flat vacua as well as general curved ones are globally attracted by the standard, square root scaling solution at early times. Open vacua asymptote to horizon-free, Milne states in both directions while closed universes exhibit more complex logarithmic singularities, starting from initial data sets of a possibly smaller dimension. We also discuss the relation of our results to the asymptotic stability of the passage through the singularity in ekpyrotic and cyclic cosmologies.
Anisotropic higher derivative gravity and inflationary universe
Kao, W. F.
2006-08-15
Stability analysis of the Kantowski-Sachs type universe in pure higher derivative gravity theory is studied in detail. The nonredundant generalized Friedmann equation of the system is derived by introducing a reduced one-dimensional generalized Kantowski-Sachs type action. Existence and stability of inflationary solution in the presence of higher derivative terms are also studied in detail. Implications to the choice of physical theories are discussed in detail in this paper.
Constraining higher derivative supergravity with scattering amplitudes
Wang, Yifan; Yin, Xi
2015-08-31
We study supersymmetry constraints on higher derivative deformations of type IIB supergravity by consideration of superamplitudes. Thus, combining constraints of on-shell supervertices and basic results from string perturbation theory, we give a simple argument for the non-renormalization theorem of Green and Sethi, and some of its generalizations.
Entanglement entropy in higher derivative holography
NASA Astrophysics Data System (ADS)
Bhattacharyya, Arpan; Kaviraj, Apratim; Sinha, Aninda
2013-08-01
We consider holographic entanglement entropy in higher derivative gravity theories. Recently Lewkowycz and Maldacena [1] have provided a method to derive the equations for the entangling surface from first principles. We use this method to compute the entangling surface in four derivative gravity. Certain interesting differences compared to the two derivative case are pointed out. For Gauss-Bonnet gravity, we show that in the regime where this method is applicable, the resulting equations coincide with proposals in the literature as well as with what follows from considerations of the stress tensor on the entangling surface. Finally we demonstrate that the area functional in Gauss-Bonnet holography arises as a counterterm needed to make the Euclidean action free of power law divergences.
Higher Education's Cultural Obligations: Views and Reviews.
ERIC Educational Resources Information Center
Reid, John Y., Ed.
Perspectives on the cultural obligations of higher education are presented in this collection of papers. Higher education's possible and probable cultural function is addressed from the perspective of business, the arts, education, and religion. Also discussed is the role of institutions of higher education in establishing a system of values,…
Cosmology with higher-derivative matter fields
NASA Astrophysics Data System (ADS)
Harko, Tiberiu; Lobo, Francisco S. N.; Saridakis, Emmanuel N.
2016-06-01
We investigate the cosmological implications of a new class of modified gravity, where the field equations generically include higher-order derivatives of the matter fields, arising from the introduction of non-dynamical auxiliary fields in the action. Imposing a flat, homogeneous and isotropic geometry, we extract the Friedmann equations, obtaining an effective dark-energy sector containing higher-derivatives of the matter energy density and pressure. For the cases of dust, radiation and stiff matter, we analyze the cosmological behavior, finding accelerating, de Sitter and non-accelerating phases, dominated by matter or dark-energy. Additionally, the effective dark-energy equation-of-state parameter can be quintessence-like, cosmological-constant-like or even phantom-like. The detailed study of these scenarios may provide signatures, that could distinguish them from other candidates of modified gravity.
Simulation in Higher Education: A Sociomaterial View
ERIC Educational Resources Information Center
Hopwood, Nick; Rooney, Donna; Boud, David; Kelly, Michelle
2016-01-01
This article presents a sociomaterial account of simulation in higher education. Sociomaterial approaches change the ontological and epistemological bases for understanding learning and offer valuable tools for addressing important questions about relationships between university education and professional practices. Simulation has grown in many…
Healthy degenerate theories with higher derivatives
NASA Astrophysics Data System (ADS)
Motohashi, Hayato; Noui, Karim; Suyama, Teruaki; Yamaguchi, Masahide; Langlois, David
2016-07-01
In the context of classical mechanics, we study the conditions under which higher-order derivative theories can evade the so-called Ostrogradsky instability. More precisely, we consider general Lagrangians with second order time derivatives, of the form L(̈phia, dot phia, phia; qi, qi) with a = 1,⋯,n and i = 1,⋯,m. For n = 1, assuming that the qi's form a nondegenerate subsystem, we confirm that the degeneracy of the kinetic matrix eliminates the Ostrogradsky instability. The degeneracy implies, in the Hamiltonian formulation of the theory, the existence of a primary constraint, which generates a secondary constraint, thus eliminating the Ostrogradsky ghost. For n > 1, we show that, in addition to the degeneracy of the kinetic matrix, one needs to impose extra conditions to ensure the presence of a sufficient number of secondary constraints that can eliminate all the Ostrogradsky ghosts. When these conditions that ensure the disappearance of the Ostrogradsky instability are satisfied, we show that the Euler-Lagrange equations, which involve a priori higher order derivatives, can be reduced to a second order system.
Black holes in higher derivative gravity.
Lü, H; Perkins, A; Pope, C N; Stelle, K S
2015-05-01
Extensions of Einstein gravity with higher-order derivative terms arise in string theory and other effective theories, as well as being of interest in their own right. In this Letter we study static black-hole solutions in the example of Einstein gravity with additional quadratic curvature terms. A Lichnerowicz-type theorem simplifies the analysis by establishing that they must have vanishing Ricci scalar curvature. By numerical methods we then demonstrate the existence of further black-hole solutions over and above the Schwarzschild solution. We discuss some of their thermodynamic properties, and show that they obey the first law of thermodynamics. PMID:25978224
Higher derivative corrections in holographic QCD
Basu, Anirban
2007-12-15
We consider the effect of the R{sup 4} term in type IIA string theory on the supergravity background dual to N{sub c} D4-branes compactified on a circle with supersymmetry breaking boundary conditions. We study the dynamics of D8-branes in this perturbed geometry in the probe approximation. This leads to an analysis of higher derivative corrections in holographic QCD beyond the supergravity approximation. We make a rough estimate of the corrections to the masses of some of the lightest (axial) vector mesons. The corrections are suppressed by a factor of (g{sub YM}{sup 2}N{sub c}){sup -3} compared to their supergravity values. We find that the masses of these mesons increase from their supergravity values.
Cosmological perturbations in non-local higher-derivative gravity
Craps, Ben; Jonckheere, Tim De; Koshelev, Alexey S. E-mail: Tim.De.Jonckheere@vub.ac.be
2014-11-01
We study cosmological perturbations in a non-local higher-derivative model of gravity introduced by Biswas, Mazumdar and Siegel. We extend previous work, which had focused on classical scalar perturbations around a cosine hyperbolic bounce solution, in three ways. First, we point out the existence of a Starobinsky solution in this model, which is more attractive from a phenomenological point of view (even though it has no bounce). Second, we study classical vector and tensor pertuxsxrbations. Third, we show how to quantize scalar and tensor perturbations in a de Sitter phase (for choices of parameters such that the model is ghost-free). Our results show that the model is well-behaved at this level, and are very similar to corresponding results in local f(R) models. In particular, for the Starobinsky solution of non-local higher-derivative gravity, we find the same tensor-to-scalar ratio as for the conventional Starobinsky model.
Statewide Boards for Higher Education: A Governor's View.
ERIC Educational Resources Information Center
Bowen, Otis R.
Otis R. Bowen, Governor of Indiana, presents his view of the role of statewide boards of higher education. After reviewing suggestions proposed by an earlier speaker, Bowen focuses on four areas deemed important for statewide boards. The first area is scope; it is suggested that a review of existing programs be made to assess the viability of the…
Benign vs. malicious ghosts in higher-derivative theories
NASA Astrophysics Data System (ADS)
Smilga, A. V.
2005-02-01
Interacting theories with higher-derivatives involve ghosts. They correspond to instabilities that display themselves at the classical level. We notice that comparatively "benign" mechanical higher-derivative systems exist, where the classical vacuum is stable with respect to small perturbations and the problems appear only at the nonperturbative level. We argue the existence of benign higher-derivative field theories which are stable with respect to small fluctuations with nonzero momenta. A particular example is the 6D N=2 higher-derivative SYM theory, which is finite and unitary at the perturbative level. The instability with respect to small fluctuations of zero-momentum modes is always present, however.
BPS states in supersymmetric chiral models with higher derivative terms
NASA Astrophysics Data System (ADS)
Nitta, Muneto; Sasaki, Shin
2014-11-01
We study the higher derivative chiral models with four supercharges and Bogomol'nyi-Prasad-Sommerfield (BPS) states in these models. The off-shell Lagrangian generically includes higher powers of the auxiliary fields F , which causes distinct on-shell branches associated with the solutions to the auxiliary fields equation. We point out that the model admits a supersymmetric completion of arbitrary higher derivative bosonic models of a single complex scalar field, and an arbitrary scalar potential can be introduced even without superpotentials. As an example, we present a supersymmetric extension of the Faddeev-Skyrme model without four time derivatives, in contrast to the previously proposed supersymmetric Faddeev-Skyrme-like model containing four time derivatives. In general, higher derivative terms together with a superpotential result in deformed scalar potentials. We find that higher derivative corrections to 1 /2 BPS domain walls and 1 /2 BPS lumps are exactly canceled out, while the 1 /4 BPS lumps (as compact baby Skyrmions) depend on a characteristic feature of the higher derivative models. We also find a new 1 /4 BPS condition for domain wall junctions, which generically receives higher derivative corrections.
A Generalization of Leibniz Rule for Higher Derivatives
ERIC Educational Resources Information Center
Thaheem, A. B.; Laradji, A.
2003-01-01
This note provides a simple method to extend the usual Leibniz rule for higher derivatives of the product of two functions to several functions, which is within the reach of freshman calculus students.
Higher derivative theories with constraints: exorcising Ostrogradski's ghost
Chen, Tai-jun; Lim, Eugene A.; Fasiello, Matteo; Tolley, Andrew J. E-mail: matte@case.edu E-mail: andrew.j.tolley@case.edu
2013-02-01
We prove that the linear instability in a non-degenerate higher derivative theory, the Ostrogradski instability, can only be removed by the addition of constraints if the original theory's phase space is reduced.
Higher derivative couplings in theories with sixteen supersymmetries
Lin, Ying -Hsuan; Shao, Shu -Heng; Yin, Xi; Wang, Yifan
2015-12-15
We give simple arguments for new non-renormalization theorems on higher derivative couplings of gauge theories to supergravity, with sixteen supersymmetries, by considerations of brane-bulk superamplitudes. This leads to some exact results on the effective coupling of D3-branes in type IIB string theory. As a result, we also derive exact results on higher dimensional operators in the torus compactification of the six dimensional (0, 2) superconformal theory.
Cosmological implications of quantum corrections and higher-derivative extension
NASA Astrophysics Data System (ADS)
Chialva, Diego; Mazumdar, Anupam
2015-01-01
We discuss the challenges for the early universe cosmology from quantum corrections, and in particular higher-derivative terms, in the gravitational and inflaton sectors of the models. The work is divided in two parts. In the first one we review the already well-known issues due to quantum corrections to the inflaton potential, in particular focusing on chaotic/slow-roll single-field models. We will point out some issues concerning the proposed mechanisms to cope with the corrections, and also argue how the presence of higher-derivative corrections could be problematic for those mechanisms. In the second part we will more directly focus on higher-derivative corrections. We will show how, in order to discuss a number of high-energy phenomena relevant to inflation (such as its actual onset) one has to deal with energy scales where the derivative expansion breaks down, presenting problems such as quantum vacuum instability and ghosts. To discuss such phenomena in the convenient framework of the effective theory, one must then abandon the derivative expansion and resort to the full nonlocal formulation of the theory, which is in fact equivalent to re-integrating back the relevant physics, but with the benefit of using a more compact single-field formalism. Finally, we will briefly discuss possible advantages offered by the presence of higher derivatives and a nonlocal theory to build better controlled UV models of inflation.
Higher-derivative superparticle in AdS3 space
NASA Astrophysics Data System (ADS)
Kozyrev, Nikolay; Krivonos, Sergey; Lechtenfeld, Olaf
2016-03-01
Employing the coset approach we construct component actions for a superparticle moving in AdS3 with N =(2 ,0 ), D =3 supersymmetry partially broken to N =2 , d =1 . These actions may contain higher time-derivative terms, which are chosen to possess the same (super)symmetries as the free superparticle. In terms of the nonlinear-realization superfields, the component actions always take a simpler form when written in terms of covariant Cartan forms. We also consider in detail the reduction to the nonrelativistic case and construct the corresponding action of a Newton-Hooke superparticle and its higher-derivative generalizations. The structure of these higher time-derivative generalizations is completely fixed by invariance under the supersymmetric Newton-Hooke algebra extended by two central charges.
Higher derivative gravity: Field equation as the equation of state
NASA Astrophysics Data System (ADS)
Dey, Ramit; Liberati, Stefano; Mohd, Arif
2016-08-01
One of the striking features of general relativity is that the Einstein equation is implied by the Clausius relation imposed on a small patch of locally constructed causal horizon. The extension of this thermodynamic derivation of the field equation to more general theories of gravity has been attempted many times in the last two decades. In particular, equations of motion for minimally coupled higher-curvature theories of gravity, but without the derivatives of curvature, have previously been derived using a thermodynamic reasoning. In that derivation the horizon slices were endowed with an entropy density whose form resembles that of the Noether charge for diffeomorphisms, and was dubbed the Noetheresque entropy. In this paper, we propose a new entropy density, closely related to the Noetheresque form, such that the field equation of any diffeomorphism-invariant metric theory of gravity can be derived by imposing the Clausius relation on a small patch of local causal horizon.
Orthographic terrain views using data derived from digital elevation models
NASA Technical Reports Server (NTRS)
Dubayah, R. O.; Dozier, J.
1986-01-01
A fast algorithm for producing three-dimensional orthographic terrain views uses digital elevation data and co-registered imagery. These views are created using projective geometry and are designed for display on high-resolution raster graphics devices. The algorithm's effectiveness is achieved by (1) the implementation of two efficient gray-level interpolation routines that offer the user a choice between speed and smoothness, and (2) a unique visible surface determination procedure based on horizon angles derived from the elevation data set.
Higher order derivatives of R-Jacobi polynomials
NASA Astrophysics Data System (ADS)
Das, Sourav; Swaminathan, A.
2016-06-01
In this work, the R-Jacobi polynomials defined on the nonnegative real axis related to F-distribution are considered. Using their Sturm-Liouville system higher order derivatives are constructed. Orthogonality property of these higher ordered R-Jacobi polynomials are obtained besides their normal form, self-adjoint form and hypergeometric representation. Interesting results on the Interpolation formula and Gaussian quadrature formulae are obtained with numerical examples.
Tackling higher derivative ghosts with the Euclidean path integral
Fontanini, Michele; Trodden, Mark
2011-05-15
An alternative to the effective field theory approach to treat ghosts in higher derivative theories is to attempt to integrate them out via the Euclidean path integral formalism. It has been suggested that this method could provide a consistent framework within which we might tolerate the ghost degrees of freedom that plague, among other theories, the higher derivative gravity models that have been proposed to explain cosmic acceleration. We consider the extension of this idea to treating a class of terms with order six derivatives, and find that for a general term the Euclidean path integral approach works in the most trivial background, Minkowski. Moreover we see that even in de Sitter background, despite some difficulties, it is possible to define a probability distribution for tensorial perturbations of the metric.
Backreaction effects due to matter coupled higher derivative gravity
NASA Astrophysics Data System (ADS)
Joshi, Lata Kh; Ramadevi, P.
2015-04-01
AdS-hydrodynamics has proven to be a useful tool for obtaining transport coefficients observed in the collective flow of strongly coupled fluids like quark gluon plasma (QGP). Particularly, the ratio of shear viscosity to entropy density η/s obtained from elliptic flow measurements can be matched with the computation done in the dual gravity theory. The experimentally observed temperature dependence of η/s requires the study of scalar matter coupled AdS gravity including higher derivative curvature corrections. We obtain the backreaction to the metric for such a matter coupled AdS gravity in D-dimensional spacetime due to the higher derivative curvature corrections. Then, we present the backreaction corrections to shear viscosity η and entropy density s.
Stable static structures in models with higher-order derivatives
Bazeia, D.; Lobão, A.S.; Menezes, R.
2015-09-15
We investigate the presence of static solutions in generalized models described by a real scalar field in four-dimensional space–time. We study models in which the scalar field engenders higher-order derivatives and spontaneous symmetry breaking, inducing the presence of domain walls. Despite the presence of higher-order derivatives, the models keep to equations of motion second-order differential equations, so we focus on the presence of first-order equations that help us to obtain analytical solutions and investigate linear stability on general grounds. We then illustrate the general results with some specific examples, showing that the domain wall may become compact and that the zero mode may split. Moreover, if the model is further generalized to include k-field behavior, it may contribute to split the static structure itself.
Degenerate higher derivative theories beyond Horndeski: evading the Ostrogradski instability
NASA Astrophysics Data System (ADS)
Langlois, David; Noui, Karim
2016-02-01
Theories with higher order time derivatives generically suffer from ghost-like instabilities, known as Ostrogradski instabilities. This fate can be avoided by considering ``degenerate'' Lagrangians, whose kinetic matrix cannot be inverted, thus leading to constraints between canonical variables and a reduced number of physical degrees of freedom. In this work, we derive in a systematic way the degeneracy conditions for scalar-tensor theories that depend quadratically on second order derivatives of a scalar field. We thus obtain a classification of all degenerate theories within this class of scalar-tensor theories. The quartic Horndeski Lagrangian and its extension beyond Horndeski belong to these degenerate cases. We also identify new families of scalar-tensor theories with the property that they are degenerate despite the nondegeneracy of the purely scalar part of their Lagrangian.
Derivation of Sky-View Factors from LIDAR Data
NASA Technical Reports Server (NTRS)
Kidd, Christopher; Chapman, Lee
2013-01-01
The use of Lidar (Light Detection and Ranging), an active light-emitting instrument, is becoming increasingly common for a range of potential applications. Its ability to provide fine resolution spatial and vertical resolution elevation data makes it ideal for a wide range of studies. This paper demonstrates the capability of Lidar data to measure sky view factors (SVF). The Lidar data is used to generate a spatial map of SVFs which are then compared against photographically-derived SVF at selected point locations. At each location three near-surface elevations measurements were taken and compared with collocated Lidar-derived estimated. It was found that there was generally good agreement between the two methodologies, although with decreasing SVF the Lidar-derived technique tended to overestimate the SVF: this can be attributed in part to the spatial resolution of the Lidar sampling. Nevertheless, airborne Lidar systems can map sky view factors over a large area easily, improving the utility of such data in atmospheric and meteorological models.
Resources for Higher Education: An Economist's View. (Reprint).
ERIC Educational Resources Information Center
Schultz, Theodore W.
1969-01-01
The limitations of economic analysis are evident when one considers the complexity of our society's needs and problems. Seven propositions which may be useful in planning and in financing higher education are: education is a form of human capital; the 3 major functions of higher education are discovering talent, instruction and research; there are…
A Socioecological View of Higher-Performing Diverse Elementary Schools
ERIC Educational Resources Information Center
Wilcox, Kristen Campbell
2013-01-01
This multiple case study relied upon a socioecological framework and the lens of resilience to investigate practices and processes that are correlated with higher academic achievement among African American, Hispanic, and English language learners. Utilizing quantitative measures for sample selection of 10 higher-performing and 5…
Perspective: New Alliances for Higher Education: Two Views.
ERIC Educational Resources Information Center
Caldwell, Philip; Chaikin, Sol
1980-01-01
The chairman of Ford Motor Company (Caldwell) and the president of the International Ladies' Garment Workers Union (Chaikin) assess current critical issues and their implications for higher education. The American economy, government regulation, productivity, taxes, competition, higher education for workers, and energy and resources are discussed.…
Higher derivative massive spin-3 models in D =2 +1
NASA Astrophysics Data System (ADS)
Dalmazi, D.; Mendonça, E. L.
2016-07-01
We find new higher derivative models describing a parity doublet of massive spin-3 modes in D =2 +1 dimensions. One of them is of fourth order in derivatives while the other one is of sixth order. They are complete, in the sense that they contain the auxiliary scalar field required to remove spurious degrees of freedom. Both of them are obtained through the master action technique starting with the usual (second-order) spin-3 Singh-Hagen model, which guarantees that they are ghost free. The fourth- and sixth-order terms are both invariant under (transverse) Weyl transformations, quite similarly to the fourth-order K -term of the "new massive gravity." The sixth-order term slightly differs from the product of the Schouten by the Einstein tensor, both of third order in derivatives. It is also possible to write down the fourth-order term as a product of a Schouten-like by an Einstein-like tensor (both of second order in derivatives) in close analogy with the K -term.
Boundary terms, variational principles, and higher derivative modified gravity
Dyer, Ethan; Hinterbichler, Kurt
2009-01-15
We discuss the criteria that must be satisfied by a well-posed variational principle. We clarify the role of Gibbons-Hawking-York type boundary terms in the actions of higher derivative models of gravity, such as F(R) gravity, and argue that the correct boundary terms are the naive ones obtained through the correspondence with scalar-tensor theory, despite the fact that variations of normal derivatives of the metric must be fixed on the boundary. We show in the case of F(R) gravity that these boundary terms reproduce the correct Arnowitt-Deser-Misner energy in the Hamiltonian formalism, and the correct entropy for black holes in the semiclassical approximation.
Duality groups, automorphic forms, and higher derivative corrections
Lambert, Neil; West, Peter
2007-03-15
We study the higher derivative corrections that occur in type II superstring theories in ten dimensions or less. Assuming invariance under a discrete duality group G(Z) we show that the generic functions of the scalar fields that occur can be identified with automorphic forms. We then give a systematic method to construct automorphic forms from a given group G(Z) together with a chosen subgroup H and a linear representation of G(Z). This construction is based on the theory of nonlinear realizations and we find that the automorphic forms contain the weights of G. We also carry out the dimensional reduction of the generic higher derivative corrections of the IIB theory to three dimensions and find that the weights of E{sub 8} occur generalizing previous results of the authors on M theory. Since the automorphic forms of this theory contain the weights of E{sub 8} we can interpret the occurrence of weights in the dimensional reduction as evidence for an underlying U-duality symmetry.
UK Higher Education Viewed through the Marketization and Marketing Lenses
ERIC Educational Resources Information Center
Nedbalová, Eva; Greenacre, Luke; Schulz, John
2014-01-01
This paper uses the Economic Market mechanisms and the 4P Marketing Mix as lenses to review the context of UK higher education (HE) and to explore the relationship between the market and marketing disciplines and practice. Four Economic Market mechanisms--autonomy, competition, price and information--are contrasted with the four Ps of marketing:…
Views of Normative Professional Conduct in Kentucky Higher Education
ERIC Educational Resources Information Center
Alford, Kenneth Ray
2011-01-01
Few studies have explored the ethical conduct of college faculty in Kentucky's institutions of higher education. This study used a causal-comparative design to determine that there were no differences among faculty at three church-affiliated and three non-church affiliated, public institutions in Kentucky. Full-time faculty employed at those…
Stakeholders' Views of South Korea's Higher Education Internationalization Policy
ERIC Educational Resources Information Center
Cho, Young Ha; Palmer, John D.
2013-01-01
The study investigated the stakeholders' perceptions of South Korea's higher education internationalization policy. Based on the research framework that defines four policy values--propriety, effectiveness, diversity, and engagement, the convergence model was employed with a concurrent mixed method sampling strategy to analyze the stakeholders'…
Details at 11. How the Media View Higher Education.
ERIC Educational Resources Information Center
Tanzer, Les
1980-01-01
Reasons are given for media myopia about higher education, and suggestions are made for improving news media perceptions: (1) using personalities to enhance the university's image; (2) establishing a program for making faculty expertise available to the media; (3) emphasizing solutions, not problems; and (4) taking risks. (MSE)
Higher Education Accreditation in View of International Contemporary Attitudes
ERIC Educational Resources Information Center
Sywelem, Mohamed M-Ghoneim; Witte, James E.
2009-01-01
Accreditation can be seen as one of several complementary measures in a quality assurance system, and the starting point is the need to maintain and improve good quality in institutions of higher education. Accreditation can play a more or less dominant role in the field of different measures that aim at monitoring, steering, recognizing and…
Moderator's view: Higher serum bicarbonate in dialysis patients is protective.
Kalantar-Zadeh, Kamyar
2016-08-01
Several observational studies have reported an association between higher serum bicarbonate level and high mortality risk in dialysis patients. However, in such studies mere discovery of associations does not allow one to infer causal relationships. This association may be related to inadequate dietary protein intake that may lead to less acid generation and hence a higher serum bicarbonate level. Since undernutrition is a strong predictor of death in hemodialysis patients, the observed association may be an epiphenomenon and not a biologically plausible relationship. Higher protein and fluid intake between two subsequent hemodialysis treatments may lead to lower serum bicarbonate level. This low bicarbonate level may appear protective, as patients with higher food intake and better appetite generally exhibit greater survival. In the contemporary three-stream proportioning system of hemodialysis treatment, the bicarbonate concentrate is separate from the acid concentrate, and the contribution of the acid concentrate organic acid (acetate, citrate or diacetate) to the delivered bicarbonate pool of the patient is negligible. The concept of 'total buffer' that assumes that the combination of bicarbonate and acetate concentrations in the dialysate are added equally as bicarbonate equivalents is likely wrong and based on the misleading notion that the acetate of the acid concentrate is fully metabolized to bicarbonate in the dialysate. Given these uncertainties it is prudent to avoid excessively high or low bicarbonate levels in dialysis patients. PMID:27411725
T-duality constraints on higher derivatives revisited
NASA Astrophysics Data System (ADS)
Hohm, Olaf; Zwiebach, Barton
2016-04-01
We ask to what extent are the higher-derivative corrections of string theory constrained by T-duality. The seminal early work by Meissner tests T-duality by reduction to one dimension using a distinguished choice of field variables in which the bosonic string action takes a Gauss-Bonnet-type form. By analyzing all field redefinitions that may or may not be duality covariant and may or may not be gauge covariant we extend the procedure to test T-duality starting from an action expressed in arbitrary field variables. We illustrate the method by showing that it determines uniquely the first-order α' corrections of the bosonic string, up to terms that vanish in one dimension. We also use the method to glean information about the O({α}^' 2}) corrections in the double field theory with Green-Schwarz deformation.
Building a holographic superconductor with higher-derivative couplings
NASA Astrophysics Data System (ADS)
Kuang, Xiao-Mei; Papantonopoulos, Eleftherios; Siopsis, George; Wang, Bin
2013-10-01
We discuss the gravitational dual of a holographic superconductor consisting of a U(1) gauge field, a complex scalar field coupled to a charged AdS black hole and a higher-derivative coupling between the U(1) gauge field and the scalar with coupling constant η. In the presence of a magnetic field, the system possesses localized spatially dependent droplet solutions which, in the low temperature limit, have smaller critical temperature for η>0 than the droplet solutions without the interaction term (η=0). In the weak magnetic field limit, the opposite behavior is observed: the critical temperature increases as we increase η. We also calculate the energy gap in the probe limit and find that it is larger for η<0 than the energy gap in the conventional case (η=0).
Polymer quantization, stability and higher-order time derivative terms
NASA Astrophysics Data System (ADS)
Cumsille, Patricio; Reyes, Carlos M.; Ossandon, Sebastian; Reyes, Camilo
2016-03-01
The possibility that fundamental discreteness implicit in a quantum gravity theory may act as a natural regulator for ultraviolet singularities arising in quantum field theory has been intensively studied. Here, along the same expectations, we investigate whether a nonstandard representation called polymer representation can smooth away the large amount of negative energy that afflicts the Hamiltonians of higher-order time derivative theories, rendering the theory unstable when interactions come into play. We focus on the fourth-order Pais-Uhlenbeck model which can be reexpressed as the sum of two decoupled harmonic oscillators one producing positive energy and the other negative energy. As expected, the Schrödinger quantization of such model leads to the stability problem or to negative norm states called ghosts. Within the framework of polymer quantization we show the existence of new regions where the Hamiltonian can be defined well bounded from below.
Pulse transmission transmitter including a higher order time derivate filter
Dress, Jr., William B.; Smith, Stephen F.
2003-09-23
Systems and methods for pulse-transmission low-power communication modes are disclosed. A pulse transmission transmitter includes: a clock; a pseudorandom polynomial generator coupled to the clock, the pseudorandom polynomial generator having a polynomial load input; an exclusive-OR gate coupled to the pseudorandom polynomial generator, the exclusive-OR gate having a serial data input; a programmable delay circuit coupled to both the clock and the exclusive-OR gate; a pulse generator coupled to the programmable delay circuit; and a higher order time derivative filter coupled to the pulse generator. The systems and methods significantly reduce lower-frequency emissions from pulse transmission spread-spectrum communication modes, which reduces potentially harmful interference to existing radio frequency services and users and also simultaneously permit transmission of multiple data bits by utilizing specific pulse shapes.
Cosmological backreaction in higher-derivative gravity expansions
NASA Astrophysics Data System (ADS)
Preston, Anthony W. H.
2016-08-01
We calculate a general effective stress-energy tensor induced by cosmological inhomogeneity in effective theories of gravity where the action is Taylor-expandable in the Riemann tensor and covariant derivatives of the Riemann tensor. This is of interest as an effective fluid that might provide an alternative to the cosmological constant, but it also applies to gravitational waves. We use an adaptation of Green and Wald's weak-averaging framework, which averages over perturbations in the field equation where the perturbation length scales are small compared to the averaging scale. In this adaptation, the length scale of the effective theory, 1/M, is also taken to be small compared with the averaging scale. This ensures that the perturbation length scales remain in fixed proportion to the length scale of the effective theory as the cosmological averaging scale is taken to be large. We find that backreaction from higher-derivative terms in the effective action can continue to be important in the late universe, given a source of sufficiently high-frequency metric perturbations. This backreaction might also provide a window on exotic particle physics in the far ultraviolet.
Transforming Higher Education: Views from Leaders around the World. Series on Higher Education.
ERIC Educational Resources Information Center
Green, Madeleine F., Ed.
This collection of 16 essays examines forces transforming higher education around the world, including demands for greater access to higher education, funding problems, the conflicting requirements of various constituencies, and pressures to contribute to a country's economic and social development. The essays include: (1) "Forces for Change"…
On higher derivatives in 3D gravity and higher-spin gauge theories
Bergshoeff, Eric A. Hohm, Olaf Townsend, Paul K.
2010-05-15
The general second-order massive field equations for arbitrary positive integer spin in three spacetime dimensions, and their 'self-dual' limit to first-order equations, are shown to be equivalent to gauge-invariant higher-derivative field equations. We recover most known equivalences for spins 1 and 2, and find some new ones. In particular, we find a non-unitary massive 3D gravity theory with a 5th order term obtained by contraction of the Ricci and Cotton tensors; this term is part of an N=2 super-invariant that includes the 'extended Chern-Simons' term of 3D electrodynamics. We also find a new unitary 6th order gauge theory for 'self-dual' spin 3.
ERIC Educational Resources Information Center
Johnston, Brenda; Elton, Lewis
2005-01-01
This article presents a comparative analysis of the German and UK higher education systems and their relationship to graduate employment. It scrutinizes the complex interconnections between (1) higher education systems and traditions; (2) the role of higher education in the state, society and the economy; and (3) the views of graduates as…
Determining Faculty and Student Views: Applications of Q Methodology in Higher Education
ERIC Educational Resources Information Center
Ramlo, Susan
2012-01-01
William Stephenson specifically developed Q methodology, or Q, as a means of measuring subjectivity. Q has been used to determine perspectives/views in a wide variety of fields from marketing research to political science but less frequently in education. In higher education, the author has used Q methodology to determine views about a variety of…
Why Is Quality in Higher Education Not Achieved? The View of Academics
ERIC Educational Resources Information Center
Cardoso, Sónia; Rosa, Maria J.; Stensaker, Bjørn
2016-01-01
Quality assurance is currently an established activity in Europe, driven either by national quality assurance agencies or by institutions themselves. However, whether quality assurance is perceived as actually being capable of promoting quality is still a question open to discussion. Based on three different views on quality derived from the…
Derivation of Electronic Course Templates for Use in Higher Education
ERIC Educational Resources Information Center
Hill, Robin K.; Fresen, Jill W.; Geng, Fawei
2012-01-01
Lecturers in higher education often consider the incorporation of web technologies into their teaching practice. Partially structured and populated course site templates could aid them in getting started with creating and deploying web-based materials and activities to enrich the teaching and learning experience. Discussions among instructional…
Hamiltonian analysis of higher derivative scalar-tensor theories
NASA Astrophysics Data System (ADS)
Langlois, David; Noui, Karim
2016-07-01
We perform a Hamiltonian analysis of a large class of scalar-tensor Lagrangians which depend quadratically on the second derivatives of a scalar field. By resorting to a convenient choice of dynamical variables, we show that the Hamiltonian can be written in a very simple form, where the Hamiltonian and the momentum constraints are easily identified. In the case of degenerate Lagrangians, which include the Horndeski and beyond Horndeski quartic Lagrangians, our analysis confirms that the dimension of the physical phase space is reduced by the primary and secondary constraints due to the degeneracy, thus leading to the elimination of the dangerous Ostrogradsky ghost. We also present the Hamiltonian formulation for nondegenerate theories and find that they contain four degrees of freedom, including a ghost, as expected. We finally discuss the status of the unitary gauge from the Hamiltonian perspective.
The New View of Biological Evolution: Organizational Applications to Higher Education.
ERIC Educational Resources Information Center
Smith, Donald T.
1993-01-01
Some organizational theorists use biological evolution as the theoretical base of their work. Many such theorists in business have applied a new view of evolution, that of punctuated equilibria, but those in higher education have not. The new theory has implications for leadership and change in college administration. (Author/MSE)
Effects of higher-order aberration correction on stereopsis at different viewing durations.
Kang, Jian; Xiao, Fei; Zhao, Junlei; Zhao, Haoxin; Hu, Yiyun; Tang, Guomao; Dai, Yun; Zhang, Yudong
2015-07-01
To better understand how the eye's optics affects stereopsis, we measured stereoacuity before and after higher-order aberration (HOA) correction with a binocular adaptive optics visual simulator. The HOAs were corrected either binocularly or monocularly in the better eye (the eye with better contrast sensitivity). A two-line stereo pattern served as the visual stimulus. Stereo thresholds at different viewing durations were obtained with the psychophysical method of constant stimuli. Binocular HOA correction led to significant improvement in stereoacuity. However, better eye HOA correction could bring either a bad degradation or a slight improvement in stereoacuity. As viewing duration increased, the stereo benefit approached the level of 1.0 for both binocular and better eye correction, suggesting that long viewing durations might weaken the effects of the eye's optical quality on stereopsis. PMID:26172611
Effects of higher-order aberration correction on stereopsis at different viewing durations
NASA Astrophysics Data System (ADS)
Kang, Jian; Xiao, Fei; Zhao, Junlei; Zhao, Haoxin; Hu, Yiyun; Tang, Guomao; Dai, Yun; Zhang, Yudong
2015-07-01
To better understand how the eye's optics affects stereopsis, we measured stereoacuity before and after higher-order aberration (HOA) correction with a binocular adaptive optics visual simulator. The HOAs were corrected either binocularly or monocularly in the better eye (the eye with better contrast sensitivity). A two-line stereo pattern served as the visual stimulus. Stereo thresholds at different viewing durations were obtained with the psychophysical method of constant stimuli. Binocular HOA correction led to significant improvement in stereoacuity. However, better eye HOA correction could bring either a bad degradation or a slight improvement in stereoacuity. As viewing duration increased, the stereo benefit approached the level of 1.0 for both binocular and better eye correction, suggesting that long viewing durations might weaken the effects of the eye's optical quality on stereopsis.
Pulse transmission receiver with higher-order time derivative pulse correlator
Dress, Jr., William B.; Smith, Stephen F.
2003-09-16
Systems and methods for pulse-transmission low-power communication modes are disclosed. A pulse transmission receiver includes: a higher-order time derivative pulse correlator; a demodulation decoder coupled to the higher-order time derivative pulse correlator; a clock coupled to the demodulation decoder; and a pseudorandom polynomial generator coupled to both the higher-order time derivative pulse correlator and the clock. The systems and methods significantly reduce lower-frequency emissions from pulse transmission spread-spectrum communication modes, which reduces potentially harmful interference to existing radio frequency services and users and also simultaneously permit transmission of multiple data bits by utilizing specific pulse shapes.
Impacts of supersymmetric higher derivative terms on inflation models in supergravity
Aoki, Shuntaro; Yamada, Yusuke
2015-07-14
We show the effects of supersymmetric higher derivative terms on inflation models in supergravity. The results show that such terms generically modify the effective kinetic coefficient of the inflaton during inflation if the cut off scale of the higher derivative operators is sufficiently small. In such a case, the η-problem in supergravity does not occur, and we find that the effective potential of the inflaton generically becomes a power type potential with a power smaller than two.
Warped AdS3 black holes in higher derivative gravity theories
NASA Astrophysics Data System (ADS)
Detournay, Stéphane; Douxchamps, Laure-Anne; Ng, Gim Seng; Zwikel, Céline
2016-06-01
We consider warped AdS3 black holes in generic higher derivatives gravity theories in 2+1 dimensions. The asymptotic symmetry group of the phase space containing these black holes is the semi-direct product of a centrally extended Virasoro algebra and an affine u(1) Kac-Moody algebra. Previous works have shown that in some specific theories, the entropy of these black holes agrees with a Cardy-like entropy formula derived for warped conformal field theories. In this paper, we show that this entropy matching continues to hold for the most general higher derivative theories of gravity. We also discuss the existence of phase transitions.
Closed string Ramond-Ramond proposed higher derivative interactions on fermionic amplitudes in IIB
NASA Astrophysics Data System (ADS)
Hatefi, Ehsan
2014-03-01
The complete form of the amplitude of one closed string Ramond-Ramond (RR), two fermionic strings and one scalar field in IIB superstring theory has been computed in detail. Deriving
NASA Technical Reports Server (NTRS)
Yan, Jue; Shu, Chi-Wang; Bushnell, Dennis M. (Technical Monitor)
2002-01-01
In this paper we review the existing and develop new continuous Galerkin methods for solving time dependent partial differential equations with higher order derivatives in one and multiple space dimensions. We review local discontinuous Galerkin methods for convection diffusion equations involving second derivatives and for KdV type equations involving third derivatives. We then develop new local discontinuous Galerkin methods for the time dependent bi-harmonic type equations involving fourth derivatives, and partial differential equations involving fifth derivatives. For these new methods we present correct interface numerical fluxes and prove L(exp 2) stability for general nonlinear problems. Preliminary numerical examples are shown to illustrate these methods. Finally, we present new results on a post-processing technique, originally designed for methods with good negative-order error estimates, on the local discontinuous Galerkin methods applied to equations with higher derivatives. Numerical experiments show that this technique works as well for the new higher derivative cases, in effectively doubling the rate of convergence with negligible additional computational cost, for linear as well as some nonlinear problems, with a local uniform mesh.
Higher derivatives and brane-localised kinetic terms in gauge theories on orbifolds
NASA Astrophysics Data System (ADS)
Ghilencea, Dumitru M.; Lee, Hyun Min; Schmidt-Hoberg, Kai
2006-08-01
We perform a detailed analysis of one-loop corrections to the self-energy of the (off-shell) gauge bosons in six-dimensional Script N = 1 supersymmetric gauge theories on orbifolds. After discussing the Abelian case in the standard Feynman diagram approach, we extend the analysis to the non-Abelian case by employing the method of an orbifold-compatible one-loop effective action for a classical background gauge field. We find that bulk higher derivative and brane-localised gauge kinetic terms are required to cancel one-loop divergences of the gauge boson self energy. After their renormalisation we study the momentum dependence of both the higher derivative coupling h(k2) and the effective gauge coupling geff(k2). For momenta smaller than the compactification scales, we obtain the 4D logarithmic running of geff(k2), with suppressed power-like corrections, while the higher derivative coupling is constant. We present in detail the threshold corrections to the low energy gauge coupling, due to the massive bulk modes. At momentum scales above the compactification scales, the higher derivative operator becomes important and leads to a power-like running of geff(k2) with respect to the momentum scale. The coefficient of this running is at all scales equal to the renormalised coupling of the higher derivative operator which ensures the quantum consistency of the model. We discuss the relation to the similar one-loop correction in the heterotic string, to show that the higher derivative operators are relevant in that case too, since the field theory limit of the one-loop string correction does not commute with the infrared regularisation of the (on-shell) string result.
Classical and quantum-mechanical axioms with the higher time derivative formalism
NASA Astrophysics Data System (ADS)
Kamalov, Timur
2013-06-01
A Newtonian mechanics model is essentially the model of a point body in an inertial reference frame. How to describe extended bodies in non-inertial (vibration) reference frames with the random initial conditions? One of the most generalized ways of descriptions (known as the higher derivatives formalism) consists in taking into account the infinite number of the higher temporal derivatives of the coordinates in the Lagrange function. Such formalism describing physical objects in the infinite dimensions space does not contradict to the quantum mechanics and infinite dimensions Hilbert space.
Holographic Dark Energy in Higher Derivative Gravity with Varying Gravitational Constant
NASA Astrophysics Data System (ADS)
Borah, Bharat; Ansari, M.
2013-09-01
In this paper we investigate the holographic dark energy scenario in higher derivative gravity with a varying gravitational constant. We introduce a kind of energy density from higher derivative gravity which has role of the same as holographic dark energy. We obtain the exact differential equation , which determine the evolution of the dark energy density based on varying gravitational constant G. We also find out a cosmological application of our work by evaluating a relation for the equation of state of dark energy for low redshifts containing varying G correction.
Second- and Higher-Order Virial Coefficients Derived from Equations of State for Real Gases
ERIC Educational Resources Information Center
Parkinson, William A.
2009-01-01
Derivation of the second- and higher-order virial coefficients for models of the gaseous state is demonstrated by employing a direct differential method and subsequent term-by-term comparison to power series expansions. This communication demonstrates the application of this technique to van der Waals representations of virial coefficients.…
A relation between deformed superspace and Lee-Wick higher-derivative theories
NASA Astrophysics Data System (ADS)
Dias, M.; Ferrari, A. F.; Palechor, C. A.; Senise, C. R., Jr.
2015-07-01
We propose a non-anticommutative superspace that relates to the Lee-Wick type of higher-derivative theories, which are known for their interesting properties and have led to proposals of phenomenologically viable higher-derivative extensions of the Standard Model. The deformation of superspace we consider does not preserve supersymmetry or associativity in general, but, we show that a non-anticommutative version of the Wess-Zumino model can be properly defined. In fact, the definition of chiral and antichiral superfields turns out to be simpler in our case than in the well known N=1/2 supersymmetric case. We show that when the theory is truncated at the first nontrivial order in the deformation parameter, supersymmetry is restored, and we end up with a well-known Lee-Wick type of higher-derivative extension of the Wess-Zumino model. Thus, we show how non-anticommutativity could provide an alternative mechanism for generating these higher-derivative theories.
Higher-order numerical methods derived from three-point polynomial interpolation
NASA Technical Reports Server (NTRS)
Rubin, S. G.; Khosla, P. K.
1976-01-01
Higher-order collocation procedures resulting in tridiagonal matrix systems are derived from polynomial spline interpolation and Hermitian finite-difference discretization. The equations generally apply for both uniform and variable meshes. Hybrid schemes resulting from different polynomial approximations for first and second derivatives lead to the nonuniform mesh extension of the so-called compact or Pade difference techniques. A variety of fourth-order methods are described and this concept is extended to sixth-order. Solutions with these procedures are presented for the similar and non-similar boundary layer equations with and without mass transfer, the Burgers equation, and the incompressible viscous flow in a driven cavity. Finally, the interpolation procedure is used to derive higher-order temporal integration schemes and results are shown for the diffusion equation.
ERIC Educational Resources Information Center
Feather, Denis
2015-01-01
This paper offers an alternative proposition to that of Lewis on identity and professional identity in higher education (HE). The proposition is provided from the narratives of 26 individual interviewees who deliver HE in college-based higher education, a viewpoint not considered by Lewis, who tends to adopt a more generalist view. Where Lewis…
Regularity properties of fiber derivatives associated with higher-order mechanical systems
NASA Astrophysics Data System (ADS)
Colombo, Leonardo; Prieto-Martínez, Pedro Daniel
2016-08-01
The aim of this work is to study fiber derivatives associated to Lagrangian and Hamiltonian functions describing the dynamics of a higher-order autonomous dynamical system. More precisely, given a function in T∗T(k-1)Q, we find necessary and sufficient conditions for such a function to describe the dynamics of a kth-order autonomous dynamical system, thus being a kth-order Hamiltonian function. Then, we give a suitable definition of (hyper)regularity for these higher-order Hamiltonian functions in terms of their fiber derivative. In addition, we also study an alternative characterization of the dynamics in Lagrangian submanifolds in terms of the solutions of the higher-order Euler-Lagrange equations.
Higher-derivative gravity with non-minimally coupled Maxwell field
NASA Astrophysics Data System (ADS)
Feng, Xing-Hui; Lü, H.
2016-04-01
We construct higher-derivative gravities with a non-minimally coupled Maxwell field. The Lagrangian consists of polynomial invariants built from the Riemann tensor and the Maxwell field strength in such a way that the equations of motion are second order for both the metric and the Maxwell potential. We also generalize the construction to involve a generic non-minimally coupled p-form field strength. We then focus on one low-lying example in four dimensions and construct the exact magnetically charged black holes. We also construct exact electrically charged z=2 Lifshitz black holes. We obtain approximate dyonic black holes for the small coupling constant or small charges. We find that the thermodynamics based on the Wald formalism disagrees with that derived from the Euclidean action procedure, suggesting this may be a general situation in higher-derivative gravities with non-minimally coupled form fields. As an application in the AdS/CFT correspondence, we study the entropy/viscosity ratio for the AdS or Lifshitz planar black holes, and find that the exact ratio can be obtained without having to know the details of the solutions, even for this higher-derivative theory.
Regularization by higher derivatives and quantum correction for N = 1 supersymmetric theories
NASA Astrophysics Data System (ADS)
Pimenov, A. B.; Soloshenko, A. A.; Stepanyantz, K. V.; Shevtsova, E. S.
2008-05-01
Some results of regularization by higher covariant derivatives used for investigation of the structure of quantum corrections in N = 1 supersymmetric theories are summarized in the present work. In particular, it is demonstrated that all integrals determining the Hell-Mann-Low functions in supersymmetric theories are integrals of total derivatives. As a consequence, in the N = 1 supersymmetric theories there exists an identity for the Green’s functions which follows from none of the symmetry theories known thus far. The problem of obtaining the exact β-function by the methods of perturbation theory is discussed.
Massive higher derivative gravity in D-dimensional anti-de Sitter spacetimes
Guellue, Ibrahim; Tekin, Bayram
2009-09-15
We find the propagator and calculate the tree level scattering amplitude between two covariantly conserved sources in an anti-de Sitter background for the most general D-dimensional quadratic, four-derivative, gravity with a Pauli-Fierz mass. We also calculate the Newtonian potential for various limits of the theory in flat space. We show how the recently introduced three-dimensional New Massive Gravity is uniquely singled out among higher derivative models as a (tree level) unitary model and that its Newtonian limit is equivalent to that of the usual massive gravity in flat space.
Higher derivative corrections to BPS black hole attractors in 4d gauged supergravity
NASA Astrophysics Data System (ADS)
Hristov, Kiril; Katmadas, Stefanos; Lodato, Ivano
2016-05-01
We analyze BPS black hole attractors in 4d gauged supergravity in the presence of higher derivative supersymmetric terms, including a Weyl-squared-type action, and determine the resulting corrections to the Bekenstein-Hawking entropy. The near-horizon geometry AdS2×S2 (or other Riemann surface) preserves half of the supercharges in N = 2 supergravity with Fayet-Iliopoulos gauging. We derive a relation between the entropy and the black hole charges that suggests via AdS/CFT how subleading corrections contribute to the supersymmetric index in the dual microscopic picture.
Ceotto, Michele; Yang, Sandy; Miller, William H
2005-01-22
A quantum theory of thermal reaction rates is presented which may be viewed as an extension of the recently developed "quantum instanton" (QI) model [W. H. Miller, Y. Zhao, M. Ceotto, and S. Yang, J. Chem. Phys. 119, 1329 (2003)]. It is based on using higher derivatives of the flux-flux autocorrelation function C(t) (as given by Miller, Schwartz, and Tromp) at t=0 to construct a short time approximation for C(t). Tests of this theory on 1d and collinear reactions, both symmetric and asymmetric, show it to be more accurate than the original QI model, giving rate constants to approximately 5% for a wide range of temperature. PMID:15740237
NASA Astrophysics Data System (ADS)
Ceotto, Michele; Yang, Sandy; Miller, William H.
2005-01-01
A quantum theory of thermal reaction rates is presented which may be viewed as an extension of the recently developed "quantum instanton" (QI) model [W. H. Miller, Y. Zhao, M. Ceotto, and S. Yang, J. Chem. Phys. 119, 1329 (2003)]. It is based on using higher derivatives of the flux-flux autocorrelation function C(t) (as given by Miller, Schwartz, and Tromp) at t=0 to construct a short time approximation for C(t). Tests of this theory on 1d and collinear reactions, both symmetric and asymmetric, show it to be more accurate than the original QI model, giving rate constants to ˜5% for a wide range of temperature.
Sensitivity analysis of complex coupled systems extended to second and higher order derivatives
NASA Technical Reports Server (NTRS)
Sobieszczanski-Sobieski, Jaroslaw
1989-01-01
In design of engineering systems, the what if questions often arise such as: what will be the change of the aircraft payload, if the wing aspect ratio is incremented by 10 percent. Answers to such questions are commonly sought by incrementing the pertinent variable, and reevaluating the major disciplinary analyses involved. These analyses are contributed by engineering disciplines that are, usually, coupled, as are the aerodynamics, structures, and performance in the context of the question above. The what if questions can be answered precisely by computation of the derivatives. A method for calculation of the first derivatives has been developed previously. An algorithm is presented for calculation of the second and higher order derivatives.
New Higher-Derivative R{sup 4} Theorems for Graviton Scattering
Berkovits, Nathan
2007-05-25
The nonminimal pure spinor formalism for the superstring is used to prove two new multiloop theorems which are related to recent higher-derivative R{sup 4} conjectures of Green, Russo, and Vanhove. The first theorem states that when 0
Anti-de Sitter-wave solutions of higher derivative theories.
Gürses, Metin; Hervik, Sigbjørn; Şişman, Tahsin Çağrı; Tekin, Bayram
2013-09-01
We show that the recently found anti-de Sitter (AdS)-plane and AdS-spherical wave solutions of quadratic curvature gravity also solve the most general higher derivative theory in D dimensions. More generally, we show that the field equations of such theories reduce to an equation linear in the Ricci tensor for Kerr-Schild spacetimes having type-N Weyl and type-N traceless Ricci tensors. PMID:25166648
IUPAC-NIST Solubility Data Series. 97. Solubility of Higher Acetylenes and Triple Bonded Derivatives
NASA Astrophysics Data System (ADS)
Fogg, Peter G. T.
2013-03-01
Solubility of Ethyne in Liquids was published in 2001 as Vol. 76 of the IUPAC-NIST Solubility Data Series. The current work extends the coverage to the solubility in liquids of higher gaseous and liquid acetylenes and to derivatives that contain a triple carbon-carbon bond. Predictive methods for estimating solubilities in water are summarised and usually give values to within an order of magnitude. The literature has been surveyed to the end of 2010.
Yamasaki, Taiga; Idehara, Katsutoshi; Xin, Xin
2016-07-01
We propose a new method to estimate muscle activity in a straightforward manner with high accuracy and relatively small computational costs by using the external input of the joint angle and its first to fourth derivatives with respect to time. The method solves the inverse dynamics problem of the skeletal system, the forward dynamics problem of the muscular system, and the load-sharing problem of muscles as a static optimization of neural excitation signals. The external input including the higher-order derivatives is required for a calculation of constraints imposed on the load-sharing problem. The feasibility of the method is demonstrated by the simulation of a simple musculoskeletal model with a single joint. Moreover, the influences of the muscular dynamics, and the higher-order derivatives on the estimation of the muscle activity are demonstrated, showing the results when the time constants of the activation dynamics are very small, and the third and fourth derivatives of the external input are ignored, respectively. It is concluded that the method can have the potential to improve estimation accuracy of muscle activity of highly dynamic motions. PMID:27211782
ERIC Educational Resources Information Center
Virolainen, Maarit Hannele; Stenstrom, Marja-Leena; Kantola, Mauri
2011-01-01
This article examines internships as part of the apprenticeship model of learning adopted in higher education. We focus on employers' views on internships, which have hitherto received only limited attention. Our study explores employers' experiences in organizing internships, and their collaboration with one University of Applied Sciences,…
Can non-local or higher derivative theories provide alternatives to inflation?
Geshnizjani, Ghazal; Ahmadi, Nahid E-mail: nahmadi@ut.ac.ir
2013-11-01
The standard mechanism for producing the observed scale-invariant power spectrum from adiabatic vacuum fluctuations relies on first order derivative of fields in the action for curvature perturbations. It has been proven [1] that, under this ansatz, any theory of early universe that matches cosmological observations should include a phase of accelerated expansion (i.e. inflation) or it has to break at least one of the following tenets of classical general relativity: Null Energy Conditions (NEC), subluminal signal propagation, or sub-Planckian energy densities. We extend this proof to a large class of theories with higher (spatial) derivative or non-local terms in the action. Interestingly, only theories in the neighborhood of Lifshitz points with ω{sub k}∝k{sup 0} and k{sup 3} remain viable.
Hanada, Masanori; Hyakutake, Yoshifumi; Nishimura, Jun; Takeuchi, Shingo
2009-05-15
We perform a direct test of the gauge-gravity duality associated with the system of N D0-branes in type IIA superstring theory at finite temperature. Based on the fact that higher derivative corrections to the type IIA supergravity action start at the order of {alpha}{sup '3}, we derive the internal energy in expansion around infinite 't Hooft coupling up to the subleading term with one unknown coefficient. The power of the subleading term is shown to be nicely reproduced by the Monte Carlo data obtained nonperturbatively on the gauge theory side at finite but large effective (dimensionless) 't Hooft coupling constant. This suggests, in particular, that the open strings attached to the D0-branes provide the microscopic origin of the black hole thermodynamics of the dual geometry including {alpha}{sup '} corrections. The coefficient of the subleading term extracted from the fit to the Monte Carlo data provides a prediction for the gravity side.
Hanada, Masanori; Hyakutake, Yoshifumi; Nishimura, Jun; Takeuchi, Shingo
2009-05-15
We perform a direct test of the gauge-gravity duality associated with the system of N D0-branes in type IIA superstring theory at finite temperature. Based on the fact that higher derivative corrections to the type IIA supergravity action start at the order of alpha;{'3}, we derive the internal energy in expansion around infinite 't Hooft coupling up to the subleading term with one unknown coefficient. The power of the subleading term is shown to be nicely reproduced by the Monte Carlo data obtained nonperturbatively on the gauge theory side at finite but large effective (dimensionless) 't Hooft coupling constant. This suggests, in particular, that the open strings attached to the D0-branes provide the microscopic origin of the black hole thermodynamics of the dual geometry including alpha;{'} corrections. The coefficient of the subleading term extracted from the fit to the Monte Carlo data provides a prediction for the gravity side. PMID:19518941
Higher-derivative corrections to type II supergravity: Four Ramond-Ramond terms
NASA Astrophysics Data System (ADS)
Bakhtiarizadeh, Hamid R.; Garousi, Mohammad R.
2015-07-01
It is known that the sphere-level S-matrix element of four type II superstrings has one kinematic factor. At the low energy limit, this factor produces the kinematic factor of the corresponding Feynman amplitudes in the supergravity. It also produces higher-derivative couplings of four strings. In this paper, we explicitly calculate the kinematic factor of four Ramond-Ramond (RR) states in the supergravity. Using this factor, we then find the eight-derivative P-even and P-odd couplings of four RR fields, including the self-dual RR five-form field strength. We show that the P-even couplings are mapped to the standard R¯4 couplings by linear T-duality and S-duality transformations. We also confirm the P-even couplings with direct calculations in type II superstring theories.
Spontaneous breakdown of Lorentz symmetry in scalar QED with higher order derivatives
Polonyi, Janos; Siwek, Alicja
2011-10-15
Scalar QED is studied with higher order derivatives for the scalar-field kinetic energy. A local potential is generated for the gauge field due to the covariant derivatives and the vacuum with nonvanishing expectation value for the scalar field, and the vector potential is constructed in the leading-order saddle-point expansion. This vacuum breaks the global gauge and Lorentz symmetry spontaneously. The unitarity of time evolution is assured in the physical, positive norm subspace, and the linearized equations of motion are calculated. The Goldstone theorem always keeps the radiation field massless. A particular model is constructed where the full set of standard Maxwell equations is recovered on the tree level, thereby relegating the effects of broken Lorentz symmetry to the level of radiative corrections.
Growth and Conflict: The Views of Chinese Private Higher Education Managers
ERIC Educational Resources Information Center
Ma, Xiaoying; Abbott, Malcom
2016-01-01
Purpose: The purpose of this paper is to report the findings of a series of interviews conducted with a number of managers of Chinese private higher education institutions on the growth of the private higher education sector in China and the relationship it has with the government. Private higher education managers in China do seem concerned with…
Higher Education and the Minerals Boom: A View from the Regions
ERIC Educational Resources Information Center
Bell, Philip
2014-01-01
This paper examines the impact of the minerals boom to date on the demand for higher education in Central Queensland, and the sustainability of higher education providers in high economic growth environments. Several datasets were used to examine changes in the demand for higher education among specific student groups within the region, the…
ERIC Educational Resources Information Center
Bergmark, Ulrika; Westman, Susanne
2016-01-01
This paper discusses a case study in teacher education in Sweden, focusing on creating spaces for student engagement through co-creating curriculum. It highlights democratic values and a multidimensional learning view as underpinning such endeavors. The main findings are that co-creating curriculum is an ambiguous process entailing unpredictable,…
Chinese International Students' and Faculty Members' Views of Plagiarism in Higher Education
ERIC Educational Resources Information Center
Grigg, Alan
2016-01-01
As the enrollment of Chinese international students (CIS) increased at a private institution in the Midwest, so did suspected cases of plagiarism. This study addressed the problem of how faculty members grappled with CIS' interpretation and application of Western-based views of plagiarism. The purpose of the study was to identify similarities and…
Higher derivative extensions of 3 d Chern-Simons models: conservation laws and stability
NASA Astrophysics Data System (ADS)
Kaparulin, D. S.; Karataeva, I. Yu.; Lyakhovich, S. L.
2015-11-01
We consider the class of higher derivative 3 d vector field models with the field equation operator being a polynomial of the Chern-Simons operator. For the nth-order theory of this type, we provide a general recipe for constructing n-parameter family of conserved second rank tensors. The family includes the canonical energy-momentum tensor, which is unbounded, while there are bounded conserved tensors that provide classical stability of the system for certain combinations of the parameters in the Lagrangian. We also demonstrate the examples of consistent interactions which are compatible with the requirement of stability.
Accioly, Antonio; Dias, Marco
2004-11-15
The problem of computing the effective nonrelativistic potential U{sub D} for the interaction of charged-scalar bosons, within the context of D-dimensional electromagnetism with a cutoff, is reduced to quadratures. It is shown that U{sub 3} cannot bind a pair of identical charged-scalar bosons; nevertheless, numerical calculations indicate that boson-boson bound states do exist in the framework of three-dimensional higher-derivative electromagnetism augmented by a topological Chern-Simons term.
Classifying BPS states in supersymmetric gauge theories coupled to higher derivative chiral models
NASA Astrophysics Data System (ADS)
Nitta, Muneto; Sasaki, Shin
2015-06-01
We study N =1 supersymmetric gauge theories coupled with higher derivative chiral models in four dimensions in the off-shell superfield formalism. We solve the equation of motion for the auxiliary fields and find two distinct on-shell structures of the Lagrangian that we call the canonical and noncanonical branches characterized by zero and nonzero auxiliary fields, respectively. We classify Bogomol'nyi-Prasado-Sommerfield (BPS) states of the models in Minkowski and Euclidean spaces. In Minkowski space, we find Abelian and non-Abelian vortices, vortex lumps (or gauged lumps with fractional lump charges) as 1 /2 BPS states in the canonical branch, and higher derivative generalization of vortices and vortex-(BPS)baby Skyrmions (or gauged BPS baby Skyrmions with fractional baby Skyrme charges) as 1 /4 BPS states in the noncanonical branch. In four-dimensional Euclidean space, we find Yang-Mills instantons trapped inside a non-Abelian vortex, intersecting vortices, and intersecting vortex-(BPS)baby Skyrmions as 1 /4 BPS states in the canonical branch but no BPS states in the noncanonical branch other than those in the Minkowski space.
Higher Education: Past, Present, and Future--A View from UNESCO.
ERIC Educational Resources Information Center
Daniel, John
2003-01-01
Briefly traces the history of the European Centre for Higher Education (UNESCO-CEPES) since its founding in 1972 and the involvement of the author in its activities, as of the 1980s, as a member of its advisory committee. Further evokes the involvement of UNESCO itself in education, particularly higher education, an involvement with roots…
ERIC Educational Resources Information Center
Shah, Mahsood; Nair, Chenicheri Sid; Stanford, Sue-Ann
2011-01-01
Governments in many countries have funded independent agencies to undertake quality audits of higher education institutions. Such agencies ensure that universities and other higher education providers have effective systems and processes to assure quality assurance in core and support areas. While external quality audits have been in place for a…
Higher Education in Romania: Evolution and Views from the Business Community.
ERIC Educational Resources Information Center
Nicolescu, Luminita
2003-01-01
Describes the evolution of higher education in Romania after 1990 and presents the results of a survey concerning the relationship between higher education and the business community in Romania. The survey had as its main objective to analyze the evolution and performance of graduates, from both private and state universities, in the labor market,…
Globalization and Higher Education in Southern California: Views from the Professoriate
ERIC Educational Resources Information Center
Weldon, Peter A.; Rexhepi, Jevdet; Chang, ChenWei; Jones, Lauren; Layton, Lucas Arribas; Liu, Amy; McKibben, Susan; Misiaszek, Greg; Olmos, Liliana; Quon, Amy; Torres, Carlos Alberto
2011-01-01
In this study, faculty at institutions of higher education in Southern California were surveyed to determine the ways they interpret the effects of globalization dynamics upon their various teaching and research activities. Faculty in the state's three higher education tiers spoke positively about the intellectual benefits to be gained by exposure…
Stable bounce and inflation in non-local higher derivative cosmology
Biswas, Tirthabir; Koshelev, Alexey S.; Mazumdar, Anupam; Vernov, Sergey Yu. E-mail: alexey.koshelev@vub.ac.be E-mail: svernov@theory.sinp.msu.ru
2012-08-01
One of the greatest problems of primordial inflation is that the inflationary space-time is past-incomplete. This is mainly because Einstein's GR suffers from a space-like Big Bang singularity. It has recently been shown that ghost-free, non-local higher-derivative ultra-violet modifications of Einstein's gravity may be able to resolve the cosmological Big Bang singularity via a non-singular bounce. Within the framework of such non-local cosmological models, we are going to study both sub- and super-Hubble perturbations around an inflationary trajectory which is preceded by the Big Bounce in the past, and demonstrate that the inflationary trajectory has an ultra-violet completion and that perturbations do not suffer from any pathologies.
Biswas, Tirthabir; Koivisto, Tomi; Mazumdar, Anupam E-mail: T.S.Koivisto@uu.nl
2010-11-01
One of the greatest problems of standard cosmology is the Big Bang singularity. Previously it has been shown that non-local ghostfree higher-derivative modifications of Einstein gravity in the ultra-violet regime can admit non-singular bouncing solutions. In this paper we study in more details the dynamical properties of the equations of motion for these theories of gravity in presence of positive and negative cosmological constants and radiation. We find stable inflationary attractor solutions in the presence of a positive cosmological constant which renders inflation geodesically complete, while in the presence of a negative cosmological constant a cyclic universe emerges. We also provide an algorithm for tracking the super-Hubble perturbations during the bounce and show that the bouncing solutions are free from any perturbative instability.
NASA Astrophysics Data System (ADS)
Borges, L. H. C.; Dias, A. G.; Ferrari, A. F.; Nascimento, J. R.; Petrov, A. Yu.
2016-05-01
We study the perturbative generation of higher-derivative Lorentz violating operators as quantum corrections to the photon effective action, originated from a specific Lorentz violation background, which has already been studied in connection with the physics of light pseudoscalars. We calculate the complete one loop effective action of the photon field through the proper-time method, using the zeta function regularization. This result can be used as a starting point to study possible effects of the Lorentz violating background we are considering in photon physics. As an example, we focus on the lowest order corrections and investigate whether they could influence the propagation of electromagnetic waves through the vacuum. We show, however, that no effects of the kind of Lorentz violation we consider can be detected in such a context, so that other aspects of photon physics have to be studied.
More on closed string induced higher derivative interactions on D-branes
NASA Astrophysics Data System (ADS)
Hatefi, Ehsan; Park, I. Y.
2012-06-01
In our continued efforts of matching full string computations with the corresponding effective field theory computations, we evaluate string theory correlators in closed forms. In particular, we consider a correlator between three super Yang-Mills vertex operators and one Ramond-Ramond C-field vertex operator: ⟨VCVϕVAVA⟩. We show that the infinite number of massless poles of this amplitude can be reproduced by the Born-Infeld action, the Wess-Zumino terms, and their higher derivative corrections. More specifically, we find, up to an on-shell ambiguity, two scalar field and two gauge field couplings to all orders in α' such that the infinite number of massless poles of the field theory amplitude exactly match the infinite number of massless poles of the S-matrix elements of ⟨VCVϕVAVA⟩. We comment on the close intertwinedness of an open string and a closed string that must be behind the matching.
Pulse transmission receiver with higher-order time derivative pulse generator
Dress, Jr., William B.; Smith, Stephen F.
2003-08-12
Systems and methods for pulse-transmission low-power communication modes are disclosed. A pulse transmission receiver includes: a front-end amplification/processing circuit; a synchronization circuit coupled to the front-end amplification/processing circuit; a clock coupled to the synchronization circuit; a trigger signal generator coupled to the clock; and at least one higher-order time derivative pulse generator coupled to the trigger signal generator. The systems and methods significantly reduce lower-frequency emissions from pulse transmission spread-spectrum communication modes, which reduces potentially harmful interference to existing radio frequency services and users and also simultaneously permit transmission of multiple data bits by utilizing specific pulse shapes.
Inflationary universe from higher derivative quantum gravity coupled with scalar electrodynamics
NASA Astrophysics Data System (ADS)
Myrzakulov, R.; Odintsov, S. D.; Sebastiani, L.
2016-06-01
We study inflation for a quantum scalar electrodynamics model in curved space-time and for higher-derivative quantum gravity (QG) coupled with scalar electrodynamics. The corresponding renormalization-group (RG) improved potential is evaluated for both theories in Jordan frame where non-minimal scalar-gravitational coupling sector is explicitly kept. The role of one-loop quantum corrections is investigated by showing how these corrections enter in the expressions for the slow-roll parameters, the spectral index and the tensor-to-scalar ratio and how they influence the bound of the Hubble parameter at the beginning of the primordial acceleration. We demonstrate that the viable inflation maybe successfully realized, so that it turns out to be consistent with last Planck and BICEP2/Keck Array data.
RG flow and thermodynamics of causal horizons in higher-derivative AdS gravity
NASA Astrophysics Data System (ADS)
Banerjee, Shamik; Bhattacharyya, Arpan
2016-05-01
In
An Examination of Higher Education: A View from the College Library.
ERIC Educational Resources Information Center
Smith, D. J.
1989-01-01
Reviews publications that examine the quality of American higher education and suggest methods for improving education at the baccalaureate level. The discussion covers the treatment of the role of college libraries in these reports, reactions of librarians to the reports, and the need for librarians to gain full participation in the education…
Sustainability, Crossdisciplinarity and Higher Education--From an Agronomic Point of View
ERIC Educational Resources Information Center
Koutsouris, Alex
2009-01-01
Nowadays, there is a growing conviction (at least in rhetoric) that sustainability is an idea whose time has come with education being a critical component in the transition towards a sustainable future. In the field of higher agricultural education, systemic approaches have, among others, triggered a lively dialogue. Topics include the challenge…
The Future of Learning: 12 Views on Emerging Trends in Higher Education
ERIC Educational Resources Information Center
Flynn, William J.; Vredevoogd, Jeff
2010-01-01
In 2009, Herman Miller, Inc., a Zeeland, Michigan-based furniture manufacturer, convened a leadership roundtable intended to identify trends that would affect higher education in the year 2015. Representatives from research universities, state colleges, community colleges, private institutions, and architectural and design firms participated in…
The Concept of Public Goods, the State, and Higher Education Finance: A View from the BRICs
ERIC Educational Resources Information Center
Carnoy, Martin; Froumin, Isak; Loyalka, Prashant K.; Tilak, Jandhyala B.
2014-01-01
Because higher education serves both public and private interests, the way it is conceived and financed is contested politically, appearing in different forms in different societies. What is public and private in education is a political--social construct, subject to various political forces, primarily interpreted through the prism of the state.…
ERIC Educational Resources Information Center
Sarrico, Claudia S.; Rosa, Maria J.; Teixeira, Pedro N.; Cardoso, Margarida F.
2010-01-01
This paper reflects on quality assessment and performance evaluation in higher education, namely by analysing the insufficient link between those two aspects. We start by reviewing the current state of the art regarding different processes and mechanisms of quality assessment and performance evaluation and discuss some of the major issues…
ERIC Educational Resources Information Center
Llurda, Enric; Cots, Josep M.; Armengol, Lurdes
2014-01-01
The key role of administrative staff in the implementation of specific institutional policies at university has often been ignored when analysing policies or attitudes related to higher education. Consequently, little is known about the administrative staff's attitudes and involvement relating to the processes of internationalisation and…
The Rural Economy: Implications for Further, Higher and Adult Education. An FEU View.
ERIC Educational Resources Information Center
Further Education Unit, London (England).
This study presents an overview of how the further, higher, and adult education (FHE) system in England should support the rural economy. It is meant to relate to the changing agricultural scene, its diversification, the movement of people, and the well-being of the community. The first seven chapters of the booklet describe the nature of the…
ERIC Educational Resources Information Center
Busher, Hugh; James, Nalita; Piela, Anna; Palmer, Anna-Marie
2014-01-01
Adult learners on Access to Higher Education courses struggled with institutional and social structures to attend their courses, but transformed their identities as learners through them. Although asymmetrical power relationships dominated the intentional learning communities of their courses, their work was facilitated by collaborative cultures…
ERIC Educational Resources Information Center
Sarrico, Cláudia S.; Rosa, Maria J.
2014-01-01
The purpose of this paper is to discuss student satisfaction with Portuguese higher education institutions, and to analyse how this varies for different types of students. A survey instrument was used to collect data on students' perceptions and expectations regarding different aspects of service provision. Based on the gap model of…
ERIC Educational Resources Information Center
Huber, Ludwig
1999-01-01
Summarizes and discusses the major arguments for and against the didactics of higher education. Considers this field's prospects. Believes that the mediation between the academic studies and qualifications of students and teachers, as well as reflection of the learning situation, will continue to increase. (CMK)
On Reflection: Mature Students' Views of Teaching and Learning on Access to Higher Education Courses
ERIC Educational Resources Information Center
Busher, Hugh; James, Nalita; Piela, Anna
2015-01-01
Mature students' experiences of learning and teaching on Access to Higher Education course are coloured by their socio-economic backgrounds, their prior experiences of learning and their relationships with their tutors. After giving informed consent, 60 students and 20 tutors across seven colleges in a region of England in 2012-2013 took part in…
A View from the Bridge: What Does the School-Reform Movement Mean for Higher Education?
ERIC Educational Resources Information Center
Sobol, Thomas
1993-01-01
Examination of the school reform movement and its relationship to higher education identified six implications for colleges and universities and ways for governing boards to support them. Factors foreseen include emergence of national educational standards, emphasis on teacher training, slow progress, increasing diversity, advancing technology,…
The park-view effect: Residential development is higher at the boundaries of protected areas.
Brambilla, Mattia; Ronchi, Silvia
2016-11-01
Land-use changes in the surrounding of protected areas might compromise their conservation efficacy, and thus the potential attractive effect that protected areas may exert on urban development is particularly concerning. We investigated whether the proximity to protected areas in a region (Lombardy, Italy) with a high density of urban areas and parks may increase the likelihood of residential development. The main change around protected areas was the loss of open areas (mostly due to development processes at the expense of arable land), which was higher in proximity of parks. Changes in residential discontinuous development were significantly and negatively related to proximity to parks, whereas changes in productive developments were unrelated to park proximity. The higher likelihood of residential development in proximity to parks is likely due to the attraction exerted by parks. The severe loss of open areas and increase of residential development around parks heavily impacted on habitat availability for a declining bird species (Alauda arvensis). Conservation policies considering also what happens around protected areas are urgently needed. PMID:27381460
Teaching mathematics online in the European Area of Higher Education: an instructor's point of view
NASA Astrophysics Data System (ADS)
Juan, Angel A.; Steegmann, Cristina; Huertas, Antonia; Martinez, M. Jesus; Simosa, J.
2011-03-01
This article first discusses how information technologies are changing the way knowledge is delivered at universities worldwide. Then, the article reviews some of the most popular learning management systems available today and some of the most useful online resources in the areas of Mathematics and Statistics. After that, some long-term experiences regarding the teaching of online courses in those areas at the Open University of Catalonia are discussed. Finally, the article presents the results of a large-scale survey performed in Spain that aims to reflect instructors' opinions and feelings about potential benefits and challenges of teaching mathematics online, as well as the role of emergent technologies in the context of the European Area of Higher Education. Therefore, this article contributes to the existing literature as an additional reference point, one based on our long-term experience in a large-scale online environment, for discussions involving mathematical e-learning.
An expansion formula with higher-order derivatives for fractional operators of variable order.
Almeida, Ricardo; Torres, Delfim F M
2013-01-01
We obtain approximation formulas for fractional integrals and derivatives of Riemann-Liouville and Marchaud types with a variable fractional order. The approximations involve integer-order derivatives only. An estimation for the error is given. The efficiency of the approximation method is illustrated with examples. As applications, we show how the obtained results are useful to solve differential equations, and problems of the calculus of variations that depend on fractional derivatives of Marchaud type. PMID:24319382
NASA Technical Reports Server (NTRS)
Kerr, R. A.
1983-01-01
In a three dimensional simulation higher order derivative correlations, including skewness and flatness factors, are calculated for velocity and passive scalar fields and are compared with structures in the flow. The equations are forced to maintain steady state turbulence and collect statistics. It is found that the scalar derivative flatness increases much faster with Reynolds number than the velocity derivative flatness, and the velocity and mixed derivative skewness do not increase with Reynolds number. Separate exponents are found for the various fourth order velocity derivative correlations, with the vorticity flatness exponent the largest. Three dimensional graphics show strong alignment between the vorticity, rate of strain, and scalar-gradient fields. The vorticity is concentrated in tubes with the scalar gradient and the largest principal rate of strain aligned perpendicular to the tubes. Velocity spectra, in Kolmogorov variables, collapse to a single curve and a short minus 5/3 spectral regime is observed.
Black holes in five-dimensional gauged supergravity with higher derivatives
NASA Astrophysics Data System (ADS)
Cremonini, Sera; Hanaki, Kentaro; Liu, James T.; Szepietowski, Phillip
2009-12-01
We examine five-dimensional Script N = 2 gauged supergravity including terms up to four derivatives. These additional terms correspond to the supersymmetric completion of R2, and were originally obtained in hep-th/0611329 using conformal supergravity techniques. Here we integrate out the auxiliary fields and obtain the on-shell action for minimal supergravity with such corrections. We then construct R-charged AdS black holes to linear order in the four derivative terms and investigate the effect of these corrections on their thermodynamical properties. Finally, we relate the geometrical coefficients governing the four-derivative corrections to gauge theory data using holographic anomaly matching. This enables us to obtain a microscopic expression for the entropy of the solutions.
iPSC-derived neurons as a higher-throughput readout for autism: Promises and pitfalls
Prilutsky, Daria; Palmer, Nathan P.; Smedemark-Margulies, Niklas; Schlaeger, Thorsten M.; Margulies, David M.; Kohane, Isaac S.
2014-01-01
The elucidation of disease etiologies and establishment of robust, scalable, high-throughput screening assays for autism spectrum disorders (ASDs) have been impeded by both inaccessibility of disease-relevant neuronal tissue and the genetic heterogeneity of the disorder. Neuronal cells derived from induced pluripotent stem cells (iPSCs) from autism patients may circumvent these obstacles and serve as relevant cell models. To date, derived cells are characterized and screened by assessing their neuronal phenotypes. These characterizations are often etiology-specific or lack reproducibility and stability. In this manuscript, we present an overview of efforts to study iPSC-derived neurons as a model for autism, and we explore the plausibility of gene expression profiling as a reproducible and stable disease marker. PMID:24374161
iPSC-derived neurons as a higher-throughput readout for autism: promises and pitfalls.
Prilutsky, Daria; Palmer, Nathan P; Smedemark-Margulies, Niklas; Schlaeger, Thorsten M; Margulies, David M; Kohane, Isaac S
2014-02-01
The elucidation of disease etiologies and establishment of robust, scalable, high-throughput screening assays for autism spectrum disorders (ASDs) have been impeded by both inaccessibility of disease-relevant neuronal tissue and the genetic heterogeneity of the disorder. Neuronal cells derived from induced pluripotent stem cells (iPSCs) from autism patients may circumvent these obstacles and serve as relevant cell models. To date, derived cells are characterized and screened by assessing their neuronal phenotypes. These characterizations are often etiology-specific or lack reproducibility and stability. In this review, we present an overview of efforts to study iPSC-derived neurons as a model for autism, and we explore the plausibility of gene expression profiling as a reproducible and stable disease marker. PMID:24374161
Higher order treatment on temporal derivative of angular flux for time-dependent MOC
Tsujita, K.; Endo, T.; Yamamoto, A.; Kamiyama, Y.; Kirimura, K.
2013-07-01
A new kinetic analysis method, whose angular dependence of temporal derivative for angular flux is accurately treated within practical memory requirement, is proposed. The method of characteristics (MOC) is being widely used for reactor analysis thanks to the advances of numerical algorithms and computer hardware. However, the computational resources, i.e., the memory capacity, can be still a crucial problem for rigorous kinetic calculations using MOC. In the straightforward approach for kinetic calculation using MOC, the segment-averaged angular fluxes should be stored on the memory in order to explicitly calculate the temporal derivative of the angular flux, which would require huge memory. Thus, in the conventional kinetic calculation code using MOC, the temporal derivative of the angular flux has been approximated as angularly isotropic in order to reduce the memory requirement (isotropic assumption). However, the approximation error caused by the conventional isotropic assumption has not been thoroughly and quantitatively investigated so far and an accurate kinetic calculation method, which can quantitatively estimate the above approximation error within practical memory storage, has not been developed. The present study tries to address this issue with a newly developed approach. Effect of the approximate treatment for the temporal derivative of angular flux is evaluated through benchmark calculations. (authors)
Discussing quantum aspects of higher-derivative 3-D gravity in the first-order formalism
NASA Astrophysics Data System (ADS)
Helayël-Neto, J. A.; de Moraes, L. M.; Vasquez, V. J.
2010-05-01
In this paper, we reassess the issue of deriving the propagators and identifying the spectrum of excitations associated to the vielbein and spin connection of (1+2)-D gravity in the presence of dynamical torsion, while working in the first-order formulation. A number of peculiarities is pointed out whenever the Chern-Simons term is taken into account along with a combination of bilinear terms in the torsion tensor. We present a procedure to derive the full set of propagators, based on an algebra of enlarged spin-type operators, and we discuss under which conditions the poles of the tree-level 2-point functions correspond to physical excitations that do not conflict with causality and unitarity.
Nonperturbative renormalization group approach for a scalar theory in higher-derivative gravity
Bonanno, A.; Zappala, D.
1997-05-01
A renormalization group study of a scalar theory coupled to gravity through a general functional dependence on the Ricci scalar in the action is discussed. A set of nonperturbative flow equations governing the evolution of the new interaction terms generated in both local potential and wave function renormalization is derived. It is shown for a specific model that these new terms play an important role in determining the scaling behavior of the system above the mass of the inflaton field. {copyright} {ital 1997} {ital The American Physical Society}
NASA Astrophysics Data System (ADS)
Özdemir (nee Güngör), Özlem; Gürkan, Perihan; Özçelik, Berrin; Oyardı, Özlem
2016-02-01
Novel β-lactam derivatives (1c-3c) (1d-3d) were produced by using 6-aminopenicillanic acid (6-APA), 7-aminocephalosporanic acid (7-ACA) and the higher amino acid Schiff bases. The synthesized compounds were characterized by elemental analysis, IR, 1H/13C NMR and UV-vis spectra. Antibacterial activities of all the higher amino acid Schiff bases (1a-3a) (1b-3b) and β-lactam derivatives were screened against three gram negative bacteria (Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Acinetobacter baumannii RSKK 02026), three gram positive bacteria (Staphylococcus aureus ATCC 25923, Enterococcus faecalis ATCC 07005, Bacillus subtilis ATCC 6633) and their drug-resistant isolates by using broth microdilution method. Two fungi (Candida albicans and Candida krusei) were used for antifungal activity.
Black holes in an asymptotically safe gravity theory with higher derivatives
Cai, Yi-Fu; Easson, Damien A. E-mail: easson@asu.edu
2010-09-01
We present a class of spherically symmetric vacuum solutions to an asymptotically safe theory of gravity containing high-derivative terms. We find quantum corrected Schwarzschild-(anti)-de Sitter solutions with running gravitational coupling parameters. The evolution of the couplings is determined by their corresponding renormalization group flow equations. These black holes exhibit properties of a classical Schwarzschild solution at large length scales. At the center, the metric factor remains smooth but the curvature singularity, while softened by the quantum corrections, persists. The solutions have an outer event horizon and an inner Cauchy horizon which equate when the physical mass decreases to a critical value. Super-extremal solutions with masses below the critical value correspond to naked singularities. The Hawking temperature of the black hole vanishes when the physical mass reaches the critical value. Hence, the black holes in the asymptotically safe gravitational theory never completely evaporate. For appropriate values of the parameters such stable black hole remnants make excellent dark matter candidates.
Sun, Hao; Du, Shasha; Liao, Guixiang; Xie, Xiao; Ren, Chen; Yuan, Ya Wei
2015-01-01
Abstract Temozolomide (TMZ) is an oral alkylating agent with established effects on the central nervous system of glioblastoma (GBM) patients. Clinical trials have demonstrated a significant impact on overall survival (OS) with TMZ. Ever since, several TMZ regimens have been designed to improve treatment efficacy by increasing the cumulative dose per cycle. We report a meta-analysis to systematically evaluate different treatment schedules of TMZ in GBM patients. All searches that were conducted in the Cochrane library, Science Direct, and PubMed Databases, and 3 randomized controlled trials (1141 patients) were included. OS and progression-free survival (PFS) were the primary outcomes to be pooled. Unexpectedly, this analysis did not reveal any OS or PFS advantage for the high cumulative dose (HCD) regimen compared with the normal cumulative dose regimen (1141 total patients; hazard ratio [HR] 1.07, 95% CI 0.94–1.22, P = 0.31). Then after analyzing the characteristics of the results from each trial, we found that the regimen with a higher peak concentration during a short-term period (daily doses ≥150 mg/m2/d within ≤7 days/cycle) always had a more superior clinical benefit. So we generated a new pooled HR of 1.10 with a 95% CI of 0.96–1.25 (P = 0.17), which prefers the high peak concentration schedule even without a significant difference. The adverse outcome also indicates a significant increased risk of leukopenia (risk ratio 1.59, 95% CI 1.03–2.46, P = 0.04) among the HCD group. Our study suggests that increasing the cumulative dose per cycle is not an ideal way to improve the efficacy of TMZ, and it will lead to increased risk for leukopenia. Future trials should be designed to examine schedules of higher peak concentration rather than the cumulative dose per cycle. PMID:25997057
The DBI action, higher-derivative supergravity, and flattening inflaton potentials
NASA Astrophysics Data System (ADS)
Bielleman, Sjoerd; Ibáñez, Luis E.; Pedro, Francisco G.; Valenzuela, Irene; Wieck, Clemens
2016-05-01
In string theory compactifications it is common to find an effective Lagrangian for the scalar fields with a non-canonical kinetic term. We study the effective action of the scalar position moduli of Type II D p-branes. In many instances the kinetic terms are in fact modified by a term proportional to the scalar potential itself. This can be linked to the appearance of higher-dimensional supersymmetric operators correcting the Kähler potential. We identify the supersymmetric dimension-eight operators describing the α' corrections captured by the D-brane Dirac-Born-Infeld action. Our analysis then allows an embedding of the D-brane moduli effective action into an {N}=1 supergravity formulation. The effects of the potential-dependent kinetic terms may be very important if one of the scalars is the inflaton, since they lead to a flattening of the scalar potential. We analyze this flattening effect in detail and compute its impact on the CMB observables for single-field inflation with monomial potentials.
Sarna, Michal; Wojcik, Katarzyna A; Hermanowicz, Pawel; Wnuk, Dawid; Burda, Kvetoslava; Sanak, Marek; Czyż, Jarosław; Michalik, Marta
2015-01-01
During asthma development, differentiation of epithelial cells and fibroblasts towards the contractile phenotype is associated with bronchial wall remodeling and airway constriction. Pathological fibroblast-to-myofibroblast transition (FMT) can be triggered by local inflammation of bronchial walls. Recently, we have demonstrated that human bronchial fibroblasts (HBFs) derived from asthmatic patients display some inherent features which facilitate their FMT in vitro. In spite of intensive research efforts, these properties remain unknown. Importantly, the role of undifferentiated HBFs in the asthmatic process was systematically omitted. Specifically, biomechanical properties of undifferentiated HBFs have not been considered in either FMT or airway remodeling in vivo. Here, we combine atomic force spectroscopy with fluorescence microscopy to compare mechanical properties and actin cytoskeleton architecture of HBFs derived from asthmatic patients and non-asthmatic donors. Our results demonstrate that asthmatic HBFs form thick and aligned 'ventral' stress fibers accompanied by enlarged focal adhesions. The differences in cytoskeleton architecture between asthmatic and non-asthmatic cells correlate with higher elastic modulus of asthmatic HBFs and their increased predilection to TGF-β-induced FMT. Due to the obvious links between cytoskeleton architecture and mechanical equilibrium, our observations indicate that HBFs derived from asthmatic bronchi can develop considerably higher static tension than non-asthmatic HBFs. This previously unexplored property of asthmatic HBFs may be potentially important for their myofibroblastic differentiation and bronchial wall remodeling during asthma development. PMID:25679502
Pawlak-Buś, Katarzyna; Gaca-Wysocka, Magdalena; Grzybowski, Andrzej; Leszczyński, Piotr
2016-03-01
Anti-malarial drugs specifically hydroxychloroquine (HCQ) or chloroquine (CQ) are very effective in treating and preventing the symptoms of systemic lupus erythematosus and other connective tissue diseases. These medications have shown to improve joint and muscle pain and arthritis, skin rashes, fatique, fever and also to control systemic signs of lupus as pericarditis or pleuritis. Shortterm and long-term treatment reduce cholesterol and have anti-platelet effect with decreasing risk of cardiovascular disease. The lupus patients on anti-malarials have also lower risk of cumulative organ damage due to reduce the amount of steroids. They may help to decrease lupus flares, mortality and are the key to controlling lupus long term outcome. Some lupus patients should be on anti-malarials for the rest of their life. For this reason, the key question is weather these drugs are absolutely safe and can be long term used in all lupus patients as a background therapy? Potential non-specific side effects occur very rare and are usually minor and last for short period. The major concerns are retinal deposits damage which could be potential reversible especially during hydroxychloroquine treatment. Nevertheless, ophthalmologist examination is still needed before starting to take HCQ or CQ and at to follow-up visits every 6-12 months. In conclusion it seems that anti-malarials are safe and have more clinical benefits than risks and from rheumatologist point of view should be more widely use in all lupus patients. PMID:27088206
Higher Education in the News: A Look into the Topics, Sources, and Views of the Print Media.
ERIC Educational Resources Information Center
Devitt, James
This study examined how higher education is represented in the press by analyzing how four leading newspapers, "The New York Times,""USA Today,""The Washington Post," and "The Wall Street Journal," covered higher education in 1997. The study analyzed a total of 610 higher education stories covering 21 topics. The 10 topics on which articles were…
ERIC Educational Resources Information Center
Graves, Scott L., Jr.; Wright, Lynda Brown
2009-01-01
This study investigates Historically Black Colleges and University (HBCU) students' and faculties' knowledge related to school psychology. A total of 165 students and 14 faculty members completed inventories that assessed the understanding and views of various psychological disciplines. Results indicated that HBCU students rated their perceived…
ERIC Educational Resources Information Center
Lindberg, Matti
2008-01-01
This article presents an analysis of the higher education-to-work transition from the perspective of the competition for job positions between students and degree holders. The conceptual framework used addresses two factors influencing the success of policies that aim to support higher education-to-work transition of youth in a knowledge society:…
ERIC Educational Resources Information Center
Carey, Philip
2013-01-01
Student engagement is increasingly part of higher education rhetoric. It is seen as a means for universities to understand and enhance the student experience. This has been prompted by a number of potentially conflicting factors. These include growing consumerism in higher education, the rise of user involvement and the notion of students as…
NASA Astrophysics Data System (ADS)
Fu, Tao; Li, Chenguang; Guo, Liping; Wang, Yanni
2015-12-01
We propose a special opinion model on Internet users' social platform selections where users only view those converging platforms as tools to maintain their communications with all of their friends or partners and one may use more than one platform at the same time. We construct the time evolution differential equations, seek the fixed points, and study their attractability and repellency by analyzing those equations. Then, we verify the analytical results and observe their accuracy by numerical simulation. The conclusion shows that in any practical system described by our model, one platform will completely eliminate its competitor sooner or later, and when the average degree of the interaction network is relatively low, the laggard may have more chance to turn the tide, but when that average degree is high, that chance is extremely limited.
ERIC Educational Resources Information Center
Sharifi, Hossein; Liu, Weisheng; Ismail, Hossam S.
2014-01-01
Higher education institutions (HEIs) have become increasingly entrepreneurial. Such a shift is highly dependent on the managers of university knowledge transfer offices whose perceptions can be critical in this transformation. This study examines such senior managers' perceptions concerning the "open" paradigm in relation with the…
ERIC Educational Resources Information Center
Townsend, Barbara K.; Bragg, Debra; Kinnick, Mary
To determine how community colleges are portrayed in academic journals, three core higher education journals and three community college journals were examined during the publication years 1990-2000. Information was sought about authorship, institutional affiliation, topics, research methods, and scope of empirical articles. Results indicated that…
ERIC Educational Resources Information Center
Leveille, David E.
2005-01-01
Higher education has become the focus of increased public debate. Stewardship of public resources, student achievement or the lack thereof, relationships and "partnerships" with business and industry in the area of research, substantial increases in tuition and fees, public perception of wrong-doing in the quality of programs, and allegations of…
ERIC Educational Resources Information Center
Houston, Don
2010-01-01
While the past two decades have seen significant expansion and harmonisation of quality assurance mechanisms in higher education, there is limited evidence of positive effects on the quality of core processes of teaching and learning. The paradox of the separation of assurance from improvement is explored. A shift in focus from surveillance to…
ERIC Educational Resources Information Center
Zhou, Rong; Xie, Baizhi
2010-01-01
In China, after many years, the current status and challenges of e-learning development in higher education have been gradually understood. The educational technology centre (ECT) serves as the key unit to promote e-learning initiatives, but the performance of some centres still trails their foreign counterparts. Under such conditions, the project…
ERIC Educational Resources Information Center
Lasagabaster, David; Cots, Josep M.; Mancho-Barés, Guzman
2013-01-01
The process of internationalisation of higher education can be seen as fluctuating between two main discourses: economic competition and academic internationalisation (Bolsman & Miller 2008). Within the former type of discourse, internationalisation is constructed as a means to generate income, in competition with other institutions, through…
ERIC Educational Resources Information Center
Cevdet, Epcacan
2015-01-01
The aim of this research is to determine high school students' opinions regarding the necessity of private courses in the transition to higher education. For this purpose, the descriptive research method has been applied. As a data collection tool, an interview which has both quantitative and qualitative structure in other words a hybrid…
ERIC Educational Resources Information Center
McNay, Ian
2008-01-01
There is a perception of crisis in UK higher education, particularly in England. This article identifies elements of the perceived crisis, quantifies the depth of the crisis from the perceptions of a sample of nearly 300 academic staff, and exemplifies the gap between stated policy and the realities of delivery. Comparisons are made between…
The Rear View Mirror and the Crystal Ball--Labor Law in Higher Education: A Management Perspective.
ERIC Educational Resources Information Center
Kerr, J. David
1984-01-01
Reviews the development of faculty collective bargaining in public higher education, as affected by federal and state constitutions and laws. Anticipates future trends. Topics covered include bargaining, organizing, determining the bargaining unit, negotiation agreements and impasses, administering the agreement, and relations between bargaining…
Selvam, Sangeetha; Yu, Zhongbo; Mao, Hanbin
2016-01-01
Due to the long-range nature of high-order interactions between distal components in a biomolecule, transition dynamics of tertiary structures is often too complex to profile using conventional methods. Inspired by the exploded view in mechanical drawing, here, we used laser tweezers to mechanically dissect high-order DNA structures into two constituting G-quadruplexes in the promoter of the human telomerase reverse transcriptase (hTERT) gene. Assisted with click-chemistry coupling, we sandwiched one G-quadruplex with two dsDNA handles while leaving the other unit free. Mechanical unfolding through these handles revealed transition dynamics of the targeted quadruplex in a native environment, which is named as native mechanical segmentation (NMS). Comparison between unfolding of an NMS construct and that of truncated G-quadruplex constructs revealed a quadruplex-quadruplex interaction with 2 kcal/mol stabilization energy. After mechanically targeting the two G-quadruplexes together, the same interaction was observed during the first unfolding step. The unfolding then proceeded through disrupting the weaker G-quadruplex at the 5'-end, followed by the stronger G-quadruplex at the 3'-end via various intermediates. Such a pecking order in unfolding well reflects the hierarchical nature of nucleic acid structures. With surgery-like precisions, we anticipate this NMS approach offers unprecedented perspective to decipher dynamic transitions in complex biomacromolecules. PMID:26626151
Selvam, Sangeetha; Yu, Zhongbo; Mao, Hanbin
2016-01-01
Due to the long-range nature of high-order interactions between distal components in a biomolecule, transition dynamics of tertiary structures is often too complex to profile using conventional methods. Inspired by the exploded view in mechanical drawing, here, we used laser tweezers to mechanically dissect high-order DNA structures into two constituting G-quadruplexes in the promoter of the human telomerase reverse transcriptase (hTERT) gene. Assisted with click-chemistry coupling, we sandwiched one G-quadruplex with two dsDNA handles while leaving the other unit free. Mechanical unfolding through these handles revealed transition dynamics of the targeted quadruplex in a native environment, which is named as native mechanical segmentation (NMS). Comparison between unfolding of an NMS construct and that of truncated G-quadruplex constructs revealed a quadruplex–quadruplex interaction with 2 kcal/mol stabilization energy. After mechanically targeting the two G-quadruplexes together, the same interaction was observed during the first unfolding step. The unfolding then proceeded through disrupting the weaker G-quadruplex at the 5′-end, followed by the stronger G-quadruplex at the 3′-end via various intermediates. Such a pecking order in unfolding well reflects the hierarchical nature of nucleic acid structures. With surgery-like precisions, we anticipate this NMS approach offers unprecedented perspective to decipher dynamic transitions in complex biomacromolecules. PMID:26626151
Pereira-Dias, B.; Hernaski, C. A.; Helayeel-Neto, J. A.
2011-04-15
The combined effects of the Lorentz-symmetry violating Chern-Simons and Ricci-Cotton actions are investigated for the Einstein-Hilbert gravity in the second-order formalism modified by higher derivative terms, and their consequences on the spectrum of excitations are analyzed. We follow the lines of previous works and build up an orthonormal basis of projector-like operators for the degrees of freedom, rather than for the spin modes of the fields. With this new basis, the attainment of the propagators is remarkably simplified and the identification of the physical and unphysical modes becomes more immediate. Our conclusion is that the only tachyon- and ghost-free model is the Einstein-Hilbert action added up by the Chern-Simons term with a timelike vector of the type v{sup {mu}=}({mu},0-vector). Spectral consistency imposes that the Ricci-Cotton term must be switched off. We then infer that gravity with Lorentz-symmetry violation imposes a drastically different constraint on the background if compared to ordinary gauge theories whenever conditions for the suppression of tachyons and ghosts are imposed.
Stockdale, Gregory; Murphy, Brian M; D'Antonio, Jennifer; Manning, Mark Cornell; Al-Azzam, Wasfi
2015-01-01
Comparing higher order structure (HOS) in therapeutic proteins is a significant challenge. Previously, we showed that changes in solution conditions produced detectable changes in the second-derivative amide I Fourier transform infrared (FTIR) spectra for a variety of model proteins. Those comparisons utilized vector-based approaches, such as spectral overlap and spectral correlation coefficients to quantify differences between spectra. In this study, chemometric analyses of the same data were performed, to classify samples into different groups based on the solution conditions received. The solution conditions were composed of various combinations of temperature, pH, and salt types. At first, principal component analysis (PCA) was used to visually demonstrate that FTIR spectra respond to changes in solution conditions, which, presumably indicates variations in HOS. This observed when samples from the same solution condition form clusters within a PCA score plot. The second approach, called soft independent modeling of class analogy (SIMCA), was conducted to account for the within-class experimental error for the lysozyme spectra. The DModX values, indicative of the distance of each spectra to their respective class models, was found to be a more sensitive quantitative indicator of changes in HOS, when compared with the modified area of overlap algorithm. The SIMCA approach provides a metric to determine whether new observations do, or do not belong to a particular class or group. Thus, SIMCA is the recommended approach when multiple samples from each condition are available. PMID:25382804
Valéry, Céline; Deville-Foillard, Stéphanie; Lefebvre, Christelle; Taberner, Nuria; Legrand, Pierre; Meneau, Florian; Meriadec, Cristelle; Delvaux, Camille; Bizien, Thomas; Kasotakis, Emmanouil; Lopez-Iglesias, Carmen; Gall, Andrew; Bressanelli, Stéphane; Le Du, Marie-Hélène; Paternostre, Maïté; Artzner, Franck
2015-01-01
External stimuli are powerful tools that naturally control protein assemblies and functions. For example, during viral entry and exit changes in pH are known to trigger large protein conformational changes. However, the molecular features stabilizing the higher pH structures remain unclear. Here we elucidate the conformational change of a self-assembling peptide that forms either small or large nanotubes dependent on the pH. The sub-angstrom high-pH peptide structure reveals a globular conformation stabilized through a strong histidine-serine H-bond and a tight histidine-aromatic packing. Lowering the pH induces histidine protonation, disrupts these interactions and triggers a large change to an extended β-sheet-based conformation. Re-visiting available structures of proteins with pH-dependent conformations reveals both histidine-containing aromatic pockets and histidine-serine proximity as key motifs in higher pH structures. The mechanism discovered in this study may thus be generally used by pH-dependent proteins and opens new prospects in the field of nanomaterials. PMID:26190377
NASA Astrophysics Data System (ADS)
Aleshin, S. S.; Kazantsev, A. E.; Skoptsov, M. B.; Stepanyantz, K. V.
2016-05-01
We consider a general non-Abelian renormalizable {N} = 1 supersymmetric gauge theory, regularized by higher covariant derivatives without breaking the BRST invariance, and calculate one-loop divergences for a general form of higher derivative regulator and of the gauge fixing term. It is demonstrated that the momentum integrals giving the one-loop β-function are integrals of double total derivatives independently of a particular choice of the higher derivative term. Evaluating them we reproduce the well-known result for the one-loop β-function. Also we find that the three-point ghost vertices with a single line of the quantum gauge superfield are not renormalized in the considered approximation.
NASA Astrophysics Data System (ADS)
Nakatsuka, Takao; Okei, Kazuhide; Takahashi, Naoya
2013-09-01
Molière's series functions of higher orders describing angular distributions of charged particle under the multiple scattering process are solved by exactly evaluating Cauchy integral with poles within the contour of integration. The functions of Molière's series giving higher-order terms are evaluated accurately by Poisson series expansion, both for spatial and projected angular distributions. Molière's series for the integrated angular distributions are also derived. Accuracy of the Molière's series expansion of higher orders is examined by comparing the reconstructed angular distributions with those derived exactly through the numerical Hankel transforms.
Givati, Assaf; Hatton, Kieron
2015-04-01
Traditional acupuncturists' quest for external legitimacy in Britain involves the standardization of their knowledge bases through the development of training schools and syllabi, formal educational structures, and, since the 1990s, the teaching of undergraduate courses within (or validated by) Higher Education Institutions (HEIs), a process which entails biomedical alignment of the curriculum. However, as holistic discourses were commonly used as a rhetorical strategy by CAM practitioners to distance themselves from biomedicine and as a source of public appeal, this 'mainstreaming' process evoked practitioners' concerns that their holistic claims are being compromised. An additional challenge is being posed by a group of academics and scientists in Britain who launched an attack on CAM courses taught in HEIs, accusing them of being 'unscientific' and 'non-academic' in nature. This paper explores the negotiation of all these challenges during the formalization of traditional acupuncture education in Britain, with a particular focus on the role of HEIs. The in-depth qualitative investigation draws on several data sets: participant observation in a university validated acupuncture course; in-depth interviews; and documentary analysis. The findings show how, as part of the formalization process, acupuncturists in Britain (re)negotiate their holistic, anti-reductionist discourses and claims in relation to contemporary societal, political and cultural forces. Moreover, the teaching and validation of acupuncture courses by HEIs may contribute to broadening acupuncturists' 'holistic awareness' of societal and cultural influences on individuals' and communities' ill-health. This investigation emphasises the dynamic and context-specific (rather than fixed and essentialized) nature of acupuncture practice and knowledge. PMID:25779622
NASA Astrophysics Data System (ADS)
Eto, Minoru; Murakami, Yoshihide
2015-03-01
Dyonic non-Abelian local/semi-global vortex strings are studied in detail in supersymmetric/non-supersymmetric Yang-Mills-Higgs theories. While the BPS tension formula is known to be the same as that for the BPS dyonic instanton, we find that the non-BPS tension formula is approximated very well by the well-known tension formula of the BPS dyon. We show that this mysterious tension formula for the dyonic non-BPS vortex stings can be understood from the perspective of a low energy effective field theory. Furthermore, we propose an efficient method to obtain an effective theory of a single vortex string, which includes not only lower derivative terms but also all order derivative corrections by making use of the tension formula. We also find a novel dyonic vortex string whose internal orientation vectors rotate in time and spiral along the string axis.
NASA Astrophysics Data System (ADS)
Wang, Lei; Zhu, Yu-Jie; Wang, Zi-Zhe; Qi, Feng-Hua; Guo, Rui
2016-04-01
We present the semirational solution in terms of the determinant form for the derivative nonlinear Schrödinger equation. It describes the nonlinear combinations of breathers and rogue waves (RWs). We show here that the solution appears as a mixture of polynomials with exponential functions. The k-order semirational solution includes k - 1 types of nonlinear superpositions, i.e., the l-order RW and (k-l)-order breather for l = 1 , 2 , … , k - 1 . By adjusting the shift and spectral parameters, we display various patterns of the semirational solutions for describing the interactions among the RWs and breathers. We find that k-order RW can be derived from a l-order RW interacting with 1/2(k - l) (k + l + 1) neighboring elements of a (k - l)-order breather for l = 1 , 2 , … , k - 1 .
Nidhi, Bhatiwada; Sharavana, Gurunathan; Ramaprasad, Talahalli R; Vallikannan, Baskaran
2015-02-01
In the present study, we appraise the anti-inflammatory efficacy of lutein oxidative degradation derivatives mediated through UV-irradiation over lutein in counteracting the inflammation induced by lipopolysaccharide (LPS) in rats (n = 5 per group). UV-irradiated lutein fragments were identified as anhydrolutein (B, C40H54O), 2,6,6-trimethylcyclohexa-1,4-dienylium (M1, C9H13), (2E,4E,6E,8E)-9-(4-hydroxy-2,6,6-trimethylcyclohex-1-1en-1-yl)-3,7-dimethylnona-2,4,6,8-tetraen-1-ylium (M2, C20H29O), 4-[(1E,3E,5E,7E)-3,7,-dimethyldeca-1,3,5,7-tetraen-1-yl]-3,5,5-methylcyclohex-3-en-1-ol (M3, C21H30O) and zeaxanthin (M4, C40H56O) and its isomers as 13'-Z zeaxanthin, 13'-Z lutein, all-trans zeaxanthin, and 9-Z lutein. Induction of inflammation by LPS significantly increased the production of nitrites (3.3 fold in the serum and 2.6 fold in the liver), prostaglandin E2 (26 fold in the serum), and pro-inflammatory cytokines like tumor necrosis factor-α (6.6 fold in the serum), and interleukin-6 (4.8 fold in the serum). Oxidative derivatives of lutein, especially M1, M2 and M3, ameliorated acute inflammation in rats by inhibiting the production of nitrites, malondialdehyde (MDA), PGE2, TNF-α, and IL-6 cytokines more efficiently than lutein in rats. The anti-inflammatory mechanism of derivatives might be related to the decrease of inflammatory cytokines and the increase of antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase, glutathione S transferase, glutathione reductase), which would result in the reduction of iNOS, COX-2 and MDA and subsequently inflammatory responses. PMID:25469663
Han, Xinyou; Fang, Kegong; Zhou, Juan; Zhao, Lu; Sun, Yuhan
2016-05-15
Highly dispersed Cu-Fe based catalysts with Fe/Cu molar ratios ranging from 0.2 to 1 were prepared via thermal decomposition of layered double hydroxides (LDHs) precursors and tested for higher alcohol synthesis (HAS) via CO hydrogenation. The catalysts were characterized using different techniques such as XRD, TEM, XPS, and H2-TPR. It was demonstrated that the Cu and Fe ions were highly dispersed in the brucite-like layers of the LDHs. With increased Fe/Cu atomic ratio, the tetrahedrally coordinated Cu ion content, Cu reduction temperatures, and the spacing of layers initially increase until the Fe/Cu ratio reaches 0.5 and then decrease. In addition to the catalytic evaluation for CO hydrogenation and catalyst characterization, the relationships between the physical-chemical properties of the catalysts and their catalytic performances were also investigated. It was also found that the alcohols/hydrocarbons ratios correlate linearly with the tetrahedrally coordinated Cu ion content. Moreover, higher reduction temperatures of Cu species as well as larger spacing between the layers in the catalyst are favorable for the synthesis of alcohols. The incorporation of a suitable amount of Fe is beneficial for the production of higher alcohols, with the best catalytic performance (alcohol selectivity of 20.77% and C2+ alcohol selectivity of 48.06%) obtained from a Fe/Cu atomic ratio of 0.5. PMID:26943001
NASA Astrophysics Data System (ADS)
Wang, Lianfang; Cao, Ang; Liu, Guilong; Zhang, Lihong; Liu, Yuan
2016-01-01
Higher alcohols synthesis (HAS) is a strong exothermal reaction which leads to the formation of hotspots on the catalysts and the hotspots result in poor selectivity, and Cu-Co based catalysts are one of the most promising to which the formation of Cu-Co alloy is critical. Therefore a new scheme was proposed, based on the excellent thermal conductivity of carbon fibers (CFs) and the uniform mixing of metal ions in layered double hydroxides (LDHs), the latter favors the formation of metallic alloy. Nanocomposites of LDHs and CFs were prepared by using co-precipitation method and used for HAS, and characterized by using FTIR, N2 adsorption-desorption, XRD, TPR, SEM and TEM techniques. In the composites, nanosheets with the typical LDHs morphology are perpendicularly grown on the surface of CFs while intersecting each other, creating a highly open and porous structure. After reduction, Cu-Co-alloy nanoparticles are formed from the LDHs. The resultant catalysts showed high activity and much high selectivity to higher alcohols. The reported methods can be expanded to prepare other LDHs/CFs composites.
Walker, Melissa M; Novak, Lea; Widener, Rebecca; Grubbs, James Aaron; King, Janice; Hale, Joanetha Y; Ochs, Martina M; Myers, Lisa E; Briles, David E; Deshane, Jessy
2016-03-01
We used two different infection models to investigate the kinetics of the PcpA-dependent pneumococcal disease in mice. In a bacteremic pneumonia model, we observed a PcpA-dependent increase in bacterial burden in the lungs, blood, liver, bronchoalveolar lavage, and spleens of mice at 24 h postinfection. This PcpA-dependent effect on bacterial burden appeared earlier (within 12 h) in the focal pneumonia model, which lacks bacteremia or sepsis. Histological changes show that the ability of pneumococci to make PcpA was associated with unresolved inflammation in both models of infection. Using our bacteremic pneumonia model we further investigated the effects of PcpA on recruitment of innate immune regulatory cells. The presence of PcpA was associated with increased IL-6 levels, suppressed production of TRAIL, and reduced infiltration of polymorphonuclear cells. The ability of pneumococci to make PcpA negatively modulated both the infiltration and apoptosis of macrophages and the recruitment of myeloid-derived suppressor-like cells. The latter have been shown to facilitate the clearance and control of bacterial pneumonia. Taken together, the ability to make PcpA was strongly associated with increased bacterial burden, inflammation, and negative regulation of innate immune cell recruitment to the lung tissue during bacteremic pneumonia. PMID:26829988
Ekinci, Yunus Levent
2016-01-01
This paper presents an easy-to-use open source computer algorithm (code) for estimating the depths of isolated single thin dike-like source bodies by using numerical second-, third-, and fourth-order horizontal derivatives computed from observed magnetic anomalies. The approach does not require a priori information and uses some filters of successive graticule spacings. The computed higher-order horizontal derivative datasets are used to solve nonlinear equations for depth determination. The solutions are independent from the magnetization and ambient field directions. The practical usability of the developed code, designed in MATLAB R2012b (MathWorks Inc.), was successfully examined using some synthetic simulations with and without noise. The algorithm was then used to estimate the depths of some ore bodies buried in different regions (USA, Sweden, and Canada). Real data tests clearly indicated that the obtained depths are in good agreement with those of previous studies and drilling information. Additionally, a state-of-the-art inversion scheme based on particle swarm optimization produced comparable results to those of the higher-order horizontal derivative analyses in both synthetic and real anomaly cases. Accordingly, the proposed code is verified to be useful in interpreting isolated single thin dike-like magnetized bodies and may be an alternative processing technique. The open source code can be easily modified and adapted to suit the benefits of other researchers. PMID:27610303
NASA Technical Reports Server (NTRS)
Bess, T. Dale; Smith, G. Louis
1987-01-01
An atlas of monthly mean outgoing longwave radiation global contour maps and associated spherical harmonic coefficients is presented. The atlas contains 36 months of continuous data from July 1975 to June 1978. The data were derived from the first Earth radiation budget experiment, which was flown on the Nimbus-6 Sun-synchronous satellite in 1975. Only the wide-field-of-view longwave measurements are cataloged in this atlas. The contour maps along with the associated sets of spherical harmonic coefficients form a valuable data set for studying different aspects of our changing climate over monthly, annual, and interannual scales in the time domain, and over regional, zonal, and global scales in the spatial domain.
NASA Astrophysics Data System (ADS)
Kwolek, J. M.; Wells, J. E.; Goodman, D. S.; Smith, W. W.
2016-05-01
Simultaneous laser locking of infrared (IR) and ultraviolet lasers to a visible stabilized reference laser is demonstrated via a Fabry-Perot (FP) cavity. LabVIEW is used to analyze the input, and an internal proportional-integral-derivative algorithm converts the FP signal to an analog locking feedback signal. The locking program stabilized both lasers to a long term stability of better than 9 MHz, with a custom-built IR laser undergoing significant improvement in frequency stabilization. The results of this study demonstrate the viability of a simple, computer-controlled, non-temperature-stabilized FP locking scheme for our applications, laser cooling of Ca+ ions, and its use in other applications with similar modest frequency stabilization requirements.
ERIC Educational Resources Information Center
Schofield, C.; Burton, F. L.
2015-01-01
The primary aim of this research was to investigate students' views of using published research and their attitudes towards the research activities of their lecturers. Although this has been examined often in university settings the focus here was on science students undertaking foundation degrees in Further Education Colleges (FECs). This was…
NASA Astrophysics Data System (ADS)
Das, Dilip
2015-07-01
There is a large class of problems in the field of fluid structure interaction where higher-order boundary conditions arise for a second-order partial differential equation. Various methods are being used to tackle these kind of mixed boundary-value problems associated with the Laplace's equation (or Helmholtz equation) arising in the study of waves propagating through solids or fluids. One of the widely used methods in wave structure interaction is the multipole expansion method. This expansion involves a general combination of a regular wave, a wave source, a wave dipole and a regular wave-free part. The wave-free part can be further expanded in terms of wave-free multipoles which are termed as wave-free potentials. These are singular solutions of Laplace's equation or two-dimensional Helmholz equation. Construction of these wave-free potentials and multipoles are presented here in a systematic manner for a number of situations such as two-dimensional non-oblique and oblique waves, three dimensional waves in two-layer fluid with free surface condition with higher order partial derivative are considered. In particular, these are obtained taking into account of the effect of the presence of surface tension at the free surface and also in the presence of an ice-cover modelled as a thin elastic plate. Also for limiting case, it can be shown that the multipoles and wave-free potential functions go over to the single layer multipoles and wave-free potential.
Hsiung, Jamie; Zhu, Danhong
2015-01-01
Oxidative stress-mediated injury to the retinal pigment epithelium (RPE) is a major factor involved in the pathogenesis of age-related macular degeneration (AMD), the leading cause of blindness in the elderly. Human embryonic stem cell (hESC)-derived RPE cells are currently being evaluated for their potential for cell therapy in AMD patients through subretinal injection of cells in suspension and subretinal placement as a polarized monolayer. To gain an understanding of how transplanted RPE cells will respond to the highly oxidatively stressed environment of an AMD patient eye, we compared the survival of polarized and nonpolarized RPE cultures following oxidative stress treatment. Polarized, nonpolarized/confluent, nonpolarized/subconfluent hESC-RPE cells were treated with H2O2. Terminal deoxynucleotidyl transferase dUTP nick end labeling stains revealed the highest amount of cell death in subconfluent hESC-RPE cells and little cell death in polarized hESC-RPE cells with H2O2 treatment. There were higher levels of proapoptotic factors (phosphorylated p38, phosphorylated c-Jun NH2-terminal kinase, Bax, and cleaved caspase 3 fragments) in treated nonpolarized RPE—particularly subconfluent cells—relative to polarized cells. On the other hand, polarized RPE cells had constitutively higher levels of cell survival and antiapoptotic signaling factors such as p-Akt and Bcl-2, as well as antioxidants superoxide dismutase 1 and catalase relative to nonpolarized cells, that possibly contributed to polarized cells’ higher tolerance to oxidative stress compared with nonpolarized RPE cells. Subconfluent cells were particularly sensitive to oxidative stress-induced apoptosis. These results suggest that implantation of polarized hESC-RPE monolayers for treating AMD patients with geographic atrophy should have better survival than injections of hESC-RPE cells in suspension. PMID:25411476
Jensen, Jonas; Tvedesøe, Claus; Rölfing, Jan Hendrik Duedal; Foldager, Casper Bindzus; Lysdahl, Helle; Kraft, David Christian Evar; Chen, Muwan; Baas, Jorgen; Le, Dang Quang Svend; Bünger, Cody Eric
2016-01-01
Introduction: The osteogenic differentiation of bone marrow-derived mesenchymal stromal cells (BMSCs) was compared with that of dental pulp-derived stromal cells (DPSCs) in vitro and in a pig calvaria critical-size bone defect model. Methods: BMSCs and DPSCs were extracted from the tibia bone marrow and the molar teeth of each pig, respectively. BMSCs and DPSCs were cultured in monolayer and on a three-dimensional (3D) polycaprolactone (PCL) – hyaluronic acid – tricalcium phosphate (HT-PCL) scaffold. Population doubling (PD), alkaline phosphatase (ALP) activity, and calcium deposition were measured in monolayer. In the 3D culture ALP activity, DNA content, and calcium deposition were evaluated. Six non-penetrating critical-size defects were made in each calvarium of 14 pigs. Three paired sub-studies were conducted: (1) empty defects vs. HT-PCL scaffolds; (2) PCL scaffolds vs. HT-PCL scaffolds; and (3) autologous BMSCs on HT-PCL scaffolds vs. autologous DPSCs on HT-PCL scaffolds. The observation time was five weeks. Bone volume fractions (BV/TV) were assessed with micro-computed tomography (μCT) and histomorphometry. Results and discussion: The results from the in vitro study revealed a higher ALP activity and calcium deposition of the DPSC cultures compared with BMSC cultures. Significantly more bone was present in the HT-PCL group than in both the pure PCL scaffold group and the empty defect group in vivo. DPSCs generated more bone than BMSCs when seeded on HT-PCL. In conclusion, DPSCs exhibited a higher osteogenic potential compared with BMSCs both in vitro and in vivo, making it a potential cell source for future bone tissue engineering. PMID:27163105
ERIC Educational Resources Information Center
Dambekalns, Lydia
2005-01-01
Educational practice today encourages interdisciplinary teaching as teachers address important basic themes from a variety of angles. In this article, the author talks about one of her successful projects that focuses on "sense of place" as one such theme, with the more specific charge of viewing Earth from both scientific and artistic…
Hiler, Daniel; Chen, Xiang; Hazen, Jennifer; Kupriyanov, Sergey; Carroll, Patrick A.; Qu, Chunxu; Xu, Beisi; Johnson, Dianna; Griffiths, Lyra; Frase, Sharon; Rodriguez, Alberto R.; Martin, Greg; Zhang, Jiakun; Jeon, Jongrye; Fan, Yiping; Finkelstein, David; Eisenman, Robert N.; Baldwin, Kristin; Dyer, Michael A.
2015-01-01
Summary Cell-based therapies to treat retinal degeneration are now being tested in clinical trials. However, it is not known if the source of stem cells is important for the production of differentiated cells suitable for transplantation. To test this, we generated iPSCs murine rod photoreceptors (r-iPSCs) and scored their ability to make retina using a standardized quantitative protocol called STEM-RET. We discovered that r-iPSCs were more efficient at producing differentiated retina than embryonic stem cells (ESCs) or fibroblast-derived iPSCs (f-iPSCs). Retinae derived from f-iPSCs had a reduction in amacrine cells and other inner nuclear layer cells. Integrated epigenetic analysis showed that DNA methylation contributes to the defects in f-iPSC retinogenesis and that rod specific CTCF insulator protein binding sites may promote retinogenes in r-iPSCs. Taken together, our data suggest that the source of stem cells are important for producing retinal neurons in 3D organ cultures. PMID:26140606
[Deregulation and Higher Education].
ERIC Educational Resources Information Center
Business Officer, 1982
1982-01-01
The extent to which the Reagan Administration has achieved its deregulation goals in the area of higher education is addressed in three articles: "Deregulation and Higher Education: The View a Year Later" (Sheldon Elliot Steinbach); "Student Financial Aid Deregulation: Rhetoric or Reality?" (Robin E. Jenkins); and "Administration Reform of Civil…
Kokubo, H; Obara, S; Minemura, K; Tanaka, T
1997-08-01
Hydroxypropyl methylcellulose (HPMC) was selected as a base polymer to develop novel enteric coating agents for acid protection which can dissolve at pH around 4, and was modified with trimellitic acid or maleic acid at various degrees of substitution. These carboxylic acids have higher dissociation constants and higher solubility in water than the carboxylic acids of existing enteric coating polymers. The synthesized polymers were micronized and dispersed in aqueous medium to determine their pKa values by potentiometric titration. The pH of dissolution and the water vapor permeability of the cast films prepared from organic solutions were also evaluated. Hydroxypropyl methylcellulose trimellitate (HPMCT) showed good acid resistance, and the pH at which it dissolves can be controlled in the range of pH 3.5 to 4.5 by varying the content of trimellityl groups and the methoxyl substitution of the base polymer. PMID:9301034
Warwick, P M; Baines, J
2000-12-01
In Australia, the process by which food energy factors are derived for food labelling purposes is under review. One of the questions of international relevance is whether energy factors should be derived using a definition of metabolisable energy (ME) or a definition of net (metabolisable) energy (NME), or some mixture of the two. ME describes the food energy available for heat production and body gains. NME deducts obligatory thermogenesis from ME in an attempt to reflect the food energy that can be converted to ATP energy within the body. Some countries use NME to derive energy factors for novel food ingredients such as sugar alcohols and polydextrose, but continue to use ME for protein, fat, carbohydrate, and alcohol. The present paper puts a case for using a consistent system (ME at the present time) for all food components. Reasons for this include: consistent application to all food components allows valid comparisons between products; food energy values and estimates of energy expenditure (food energy requirements) should be directly comparable; NME does not account for all sources of thermogenesis; differences between ME and NME for sugar alcohols and polydextrose are small in the context of the whole diet; and the ME system does not preclude information about metabolic efficiency being provided as additional information. Any major change to the way in which energy values are expressed (e.g. global adoption of the NME system) merits wide discussion among the human nutrition community. One aim of this present paper is to stimulate this discussion. PMID:11177207
2012-01-01
Background Cultivated peanut (Arachis hypogaea L.) is an important crop worldwide, valued for its edible oil and digestible protein. It has a very narrow genetic base that may well derive from a relatively recent single polyploidization event. Accordingly molecular markers have low levels of polymorphism and the number of polymorphic molecular markers available for cultivated peanut is still limiting. Results Here, we report a large set of BAC-end sequences (BES), use them for developing SSR (BES-SSR) markers, and apply them in genetic linkage mapping. The majority of BESs had no detectable homology to known genes (49.5%) followed by sequences with similarity to known genes (44.3%), and miscellaneous sequences (6.2%) such as transposable element, retroelement, and organelle sequences. A total of 1,424 SSRs were identified from 36,435 BESs. Among these identified SSRs, dinucleotide (47.4%) and trinucleotide (37.1%) SSRs were predominant. The new set of 1,152 SSRs as well as about 4,000 published or unpublished SSRs were screened against two parents of a mapping population, generating 385 polymorphic loci. A genetic linkage map was constructed, consisting of 318 loci onto 21 linkage groups and covering a total of 1,674.4 cM, with an average distance of 5.3 cM between adjacent loci. Two markers related to resistance gene homologs (RGH) were mapped to two different groups, thus anchoring 1 RGH-BAC contig and 1 singleton. Conclusions The SSRs mined from BESs will be of use in further molecular analysis of the peanut genome, providing a novel set of markers, genetically anchoring BAC clones, and incorporating gene sequences into a linkage map. This will aid in the identification of markers linked to genes of interest and map-based cloning. PMID:22260238
NASA Technical Reports Server (NTRS)
Bess, T. Dale; Smith, G. Louis
1987-01-01
An atlas of monthly mean outgoing longwave radiation global contour maps and associated spherical harmonic coefficients is presented. The atlas contains 84 months of continuous data from November 1978 to October 1985. The data were derived from the second Earth radiation budget experiment, which was flown on the Nimbus 7 Sun-synchronous satellite in 1978. This data set is a companion set and extension to a similar report of the Nimbus 6 satellite. Together these two reports give a data set covering a 10 year time period and will be very valuable in studying different aspects of our changing climate over monthly, annual, and interannual scales in the time domain and over regional, zonal, and global scales in the spatial domain.
NASA Technical Reports Server (NTRS)
Bess, T. Dale; Smith, G. Louis
1991-01-01
An atlas of monthly outgoing longwave radiation global contour maps and associated spherical harmonic coefficients is presented. The atlas contains 23 months of data from November 1985 to October 1987 . The data were derived from the second Earth Radiation Budget (ERB) package, which was flown on the Nimbus 7 Sun-synchronous satellite in 1987. This data set is a companion set and extension to similar atlases that documented 10 years of outgoing longwave radiation results from Nimbus 6 and Nimbus 7 satellites. This atlas and the companion atlases give a data set covering a 12-year time period and will be very useful in studying different aspects of our changing climate. The data set also provides a 3-year overlap with the current Earth Radiation Budget Experiment (ERBE).
Clabo, D.A. Jr.
1987-04-01
Inclusion of the anharmonicity normal mode vibrations (i.e., the third and fourth (and higher) derivatives of a molecular Born-Oppenheimer potential energy surface) is necessary in order to theoretically reproduce experimental fundamental vibrational frequencies of a molecule. Although ab initio determinations of harmonic vibrational frequencies may give errors of only a few percent by the inclusion of electron correlation within a large basis set for small molecules, in general, molecular fundamental vibrational frequencies are more often available from high resolution vibration-rotation spectra. Recently developed analytic third derivatives methods for self-consistent-field (SCF) wavefunctions have made it possible to examine with previously unavailable accuracy and computational efficiency the anharmonic force fields of small molecules.
ERIC Educational Resources Information Center
Thompson, Dennis F.
1989-01-01
John Stuart Mill's principle of liberty is discussed with the view that it needs to be revised to guide moral judgments in higher education. Three key elements need to be modified: the action that is constrained; the constraint on the action; and the agent whose action is constrained. (MLW)
Evaluation of expressions involving higher order derivations
NASA Technical Reports Server (NTRS)
Grossman, Robert
1990-01-01
The local geometric properties of a nonlinear control system defined by vector fields E(sub 1),..., E(sub M) are determined by the algebraic properties of the iterated Lie brackets of the E(sub j)'s. The problem of rewriting expressions is examined involving the E(sub j)'s in terms of the D(sub mu)'s in such a way as to handle effectively any cancellation occurring due to commuting of the D(sub mu)'s. A data structure is introduced which allows us to organize the computation to take advantage of the symmetries in the expression and reduce the operation count.
Resource Purpose:Montana View is a decision support tool designed to assist with environmental and natural resource management in Montana. Montana View is based on a review platform and provides an interface for various environmental queries. It also provides online access...
ERIC Educational Resources Information Center
Congress of the U.S., Washington, DC. House Committee on Education and the Workforce.
This volume presents the report of the Committee on Education and the Workforce regarding the Higher Education Amendments of 1998, including additional and dissenting views. The report, which features both the text of the amendments and the Committee's review of them, covers the following sections of the proposed legislation (H.R. 6), set to go…
Cultural Capital and Agency: Connecting Critique and Curriculum in Higher Education
ERIC Educational Resources Information Center
Clegg, Sue
2011-01-01
This paper explores some of the unresolved tensions in higher education systems and the contradiction between widening participation and the consolidation of social position. It shows how concepts of capital derived from Bourdieu, Coleman and Putnam provide a powerful basis for critique, but risk a deficit view of students from less privileged…
ERIC Educational Resources Information Center
Hendrickson, Robert M.; Gregory, Dennis E.
Decisions made by federal and state courts during 1983 concerning higher education are reported in this chapter. Issues of employment and the treatment of students underlay the bulk of the litigation. Specific topics addressed in these and other cases included federal authority to enforce regulations against age discrimination and to revoke an…
ERIC Educational Resources Information Center
Hendrickson, Robert M.
Litigation in 1987 was very brisk with an increase in the number of higher education cases reviewed. Cases discussed in this chapter are organized under four major topics: (1) intergovernmental relations; (2) employees, involving discrimination claims, tenured and nontenured faculty, collective bargaining and denial of employee benefits; (3)…
ERIC Educational Resources Information Center
Hendrickson, Robert M.; Finnegan, Dorothy E.
The higher education case law in 1988 is extensive. Cases discussed in this chapter are organized under five major topics: (1) intergovernmental relations; (2) employees, involving discrimination claims, tenured and nontenured faculty, collective bargaining, and denial of employee benefits; (3) students, involving admissions, financial aid, First…
ERIC Educational Resources Information Center
Hendrickson, Robert M.
This eighth chapter of "The Yearbook of School Law, 1986" summarizes and analyzes over 330 state and federal court cases litigated in 1985 in which institutions of higher education were involved. Among the topics examined were relationships between postsecondary institutions and various governmental agencies; discrimination in the employment of…
Aspects of metric-like higher-spin geometry
Francia, D.
2012-09-24
We consider the higher-derivative equations obtained setting to zero the divergence of the higher-spin curvatures in metric-like form, showing their equivalence to the second-order equations emerging from the tensionless limit of open string field theory, propagating reducible spectra of particles with different spins. This result can be viewed as complementary to the possibility of setting to zero a single trace of the higher-spin field strengths, yielding an equation known to imply Fronsdal's equation in the compensator form. We review the general context and results obtained in the investigation of metric-like higher-spin geometry, the structure of the corresponding non-local actions, together with their links to more conventional, local forms including a recently proposed one for higher-spin theories with transverse gauge invariance.
ERIC Educational Resources Information Center
Rosenfeld, Mark
2003-01-01
Discusses how, like Australia, Canadian higher education has experienced large-scale cuts in government funding, the deregulation of tuition and general cost shifting to students, inability to accommodate increased student demand, faculty "brain drain" and shortages, and an erosion of public policy toward viewing higher education as a business.…
ERIC Educational Resources Information Center
Garforth, Graham
2011-01-01
In London particularly there is increasing competitiveness for jobs and a need for transferable tertiary industry skills. There has been decades of change in vocational education and training; but there is evidence that little has changed to improve the chances of students progression to higher education and employment. With the age that students…
ERIC Educational Resources Information Center
United Nations Educational, Scientific, and Cultural Organization, Bangkok (Thailand).
Proceedings of a 1983 International Conference of states sponsored by the United Nations Educational, Scientific, and Cultural Organization (UNESCO) are presented. The focus was the adoption of the Regional Convention on the Recognition of Studies, Diplomas, and Degrees in Higher Education in Asia and the Pacific. Emphasis was placed on the…
Higher dimensional Hadamard matrices
NASA Technical Reports Server (NTRS)
Schlichta, P. J.
1979-01-01
The paper defines higher dimensional Hadamard matrices and enumerates on some of the simplest three-, four-, and five-dimensional cases and procedures for generating them. Special emphasis is given to proper matrices that have a dimensional hierarchy of orthogonalities. It is determined that this property lends itself primarily to the application of higher dimensional Hadamard matrices to error-correcting codes. A list of derived statements for n-dimensional Hadamard matrices are given, as well as a definition of Hadamard matrix families, such as minimal, Petrie polygon, antipodal (n-2)-dimensional sections, and double proximity shells.
Koenderink, Jan; Wijntjes, Maarten; van Doorn, Andrea
2013-01-01
The “zograscope” is a “visual aid” (commonly known as “optical machine” in the 18th century) invented in the mid-18th century, and in general use until the early 20th century. It was intended to view single pictures (thus not stereographic pairs) with both eyes. The optics approximately eliminates the physiological cues (binocular disparity, vergence, accommodation, movement parallax, and image blur) that might indicate the flatness of the picture surface. The spatial structure of pictorial space is due to the remaining pictorial cues. As a consequence, many (or perhaps most) observers are aware of a heightened “plasticity” of the pictorial content for zograscopic as compared with natural viewing. We discuss the optics of the zograscope in some detail. Such an analysis is not available in the literature, whereas common “explanations” of the apparatus are evidently nonsensical. We constructed a zograscope, using modern parts, and present psychophysical data on its performance. PMID:23799196
NASA Astrophysics Data System (ADS)
Gangodagamage, C.; Rowland, J. C.; Hubbard, S. S.; Brumby, S. P.; Liljedahl, A.; Wainwright, H. M.; Sloan, V. L.; Altmann, G.; Skurikhin, A. N.; Shelef, E.; Wilson, C. J.; Dafflon, B.; Peterson, J.; Ulrich, C.; Gibbs, A.; Tweedie, C. E.; Painter, S. L.; Wullschleger, S. D.
2014-12-01
Landscape attributes that vary with micro-topography, such as active layer thickness (ALT) in ice-wedge polygon ground, are labor-intensive to document in the field at large spatial extents, necessitating remotely sensed methods. Robust techniques to estimate ALT over large areas would improve understanding of coupled dynamics between permafrost, hydrology and landsurface processes, and improve simulations of the rate and timing of release of soil carbon from permafrost settings. In particular, it would provide critically needed data to parameterize and initialize soil property information in permafrost models and evaluate model predictions for large, complex domains. In this work, we demonstrate a new data fusion approach using high-resolution remotely sensed data for estimating cm scale ALT in a 5 km2 area of ice-wedge polygon terrain in Barrow, Alaska. We used topographic (directed distance, slope, wavelet-curvature) and spectral (NDVI) metrics derived from multisensor data obtained from LiDAR and WorldView-2 platforms to develop a simple data fusion algorithm using statistical machine learning. This algorithm was used to estimate ALT (2 m spatial resolution) across the study area. A comparison of the estimates with ground-based measurements documented the accuracy (±4.4 cm, r2=0.76) of the approach. Our findings suggest that the broad climatic variability associated with warming air temperature will govern the regional averages of ALT, but the smaller-scale variability could be controlled by local eco-hydro-geomorphic variables. This work demonstrates a path forward for mapping subsurface properties over large areas from readily available remote sensing data. Methodology of Mapping and Characterization Polygons:We convolve LiDAR elevations with multiscale wavelets and objectively chose appropriate scales to map interconnected troughs of high- and low-centered polygons. For the ice wedges where LiDAR surface expressions (troughs) are not well developed, we used
Crawford, M.
1987-06-05
Public Perceptions of Biotechnology is the second of a series of reports entitled New Developments in Biotechnology. This latest study is based on interviews with 1273 American adults and has a margin of error of 2 to 3%. Participants were queried on their attitudes toward science and the environment, as well as on matters directly related to biotechnology. Whereas public interest in science has eroded slightly, there is increased optimism about the benefits to be derived from science. Some 62% of the sample thought the benefits will outweigh the risks, whereas in 1980 a Harris survey indicated that only 58% of the country held this view.
Multi-View Learning With Incomplete Views.
Xu, Chang; Tao, Dacheng; Xu, Chao
2015-12-01
One underlying assumption of the conventional multi-view learning algorithms is that all examples can be successfully observed on all the views. However, due to various failures or faults in collecting and pre-processing the data on different views, we are more likely to be faced with an incomplete-view setting, where an example could be missing its representation on one view (i.e., missing view) or could be only partially observed on that view (i.e., missing variables). Low-rank assumption used to be effective for recovering the random missing variables of features, but it is disabled by concentrated missing variables and has no effect on missing views. This paper suggests that the key to handling the incomplete-view problem is to exploit the connections between multiple views, enabling the incomplete views to be restored with the help of the complete views. We propose an effective algorithm to accomplish multi-view learning with incomplete views by assuming that different views are generated from a shared subspace. To handle the large-scale problem and obtain fast convergence, we investigate a successive over-relaxation method to solve the objective function. Convergence of the optimization technique is theoretically analyzed. The experimental results on toy data and real-world data sets suggest that studying the incomplete-view problem in multi-view learning is significant and that the proposed algorithm can effectively handle the incomplete views in different applications. PMID:26469202
Rybka, Karin; Toal, Siobhan E; Verbaro, Daniel J; Mathieu, Daniel; Schwalbe, Harald; Schweitzer-Stenner, Reinhard
2013-06-01
In the preceding paper, we found that ensembles of tripeptides with long or bulky chains can include up to 20% of various turns. Here, we determine the structural and thermodynamic characteristics of GxG peptides with short polar and/or ionizable central residues (D, N, C), whose conformational distributions exhibit higher than average percentage (>20%) of turn conformations. To probe the side-chain conformations of these peptides, we determined the (3)J(H(α),H(β)) coupling constants and derived the population of three rotamers with χ1 -angles of -60°, 180° and 60°, which were correlated with residue propensities by DFT-calculations. For protonated GDG, the rotamer distribution provides additional evidence for asx-turns. A comparison of vibrational spectra and NMR coupling constants of protonated GDG, ionized GDG, and the protonated aspartic acid dipeptide revealed that side chain protonation increases the pPII content at the expense of turn populations. The charged terminal groups, however, have negligible influence on the conformational properties of the central residue. Like protonated GDG, cationic GCG samples asx-turns to a significant extent. The temperature dependence of the UVCD spectra and (3)J(H(N)H(α)) constants suggest that the turn populations of GDG and GNG are practically temperature-independent, indicating enthalpic and entropic stabilization. The temperature-independent J-coupling and UVCD spectra of GNG require a three-state model. Our results indicate that short side chains with hydrogen bonding capability in GxG segments of proteins may serve as hinge regions for establishing compact structures of unfolded proteins and peptides. PMID:23229867
Student Influence and Higher Education.
ERIC Educational Resources Information Center
Juola, Arvo E.
Since 1965, student views and feelings have influenced great changes in higher education, sometimes to the detriment of long-term interests in academic institutions and colleges. One conspicuous recent trend is the desire of college students for more influence, impact, or power. Other prevalent attitudes may be characterized as a desire to be…
Rethinking Higher Education Capital Finance.
ERIC Educational Resources Information Center
King, George A.
1988-01-01
Capital finance in institutions of higher education is analyzed in light of changes in the Tax Reform Act of 1986 affecting the ability of institutions to finance capital projects and the likelihood of changes in the government's view of tax-exempt financing. The options for colleges and universities are analyzed in the following areas: (1)…
Semistrict higher gauge theory
NASA Astrophysics Data System (ADS)
Jurčo, Branislav; Sämann, Christian; Wolf, Martin
2015-04-01
We develop semistrict higher gauge theory from first principles. In particular, we describe the differential Deligne cohomology underlying semistrict principal 2-bundles with connective structures. Principal 2-bundles are obtained in terms of weak 2-functors from the Čech groupoid to weak Lie 2-groups. As is demonstrated, some of these Lie 2-groups can be differentiated to semistrict Lie 2-algebras by a method due to Ševera. We further derive the full description of connective structures on semistrict principal 2-bundles including the non-linear gauge transformations. As an application, we use a twistor construction to derive superconformal constraint equations in six dimensions for a non-Abelian tensor multiplet taking values in a semistrict Lie 2-algebra.
Branding Canadian Higher Education. CBIE Research
ERIC Educational Resources Information Center
Kizilbash, Zainab
2011-01-01
The branding of national higher education systems is a global trend that has become increasingly common over the last decade. One of the main motives driving this trend is the view that branding a national higher education system will increase that country's market share of international students. This is evident as national higher education…
Synthesis of higher monocarboxylic acids
Taikov, B.F.; Novakovskii, E.M.; Zhelkovskaya, V.P.; Shadrova, V.N.; Shcherbik, P.K.
1981-01-01
Brown-coal and peat waxes contain higher monocarboxylic acids, alcohols and esters of them as their main components. In view of this, considerable interest is presented by the preparation of individual compounds among those mentioned above, which is particularly important in the study of the composition and development of the optimum variants of the chemical processing of the waxes. In laboratory practice, to obtain higher monocarboxylic acids use is generally made of electrosynthesis according to Kolbe which permits unbranched higher aliphatic acids with given lengths of the hydrocarbon chain to be obtained. The aim of the present work was to synthesize higher monocarboxylic acids: arachidic, behenic, lignoceric, pentacosanoic, erotic, heptacosanoic, montanic, nonacosanoic, melissic, dotriacontanoic and tetratriacontanoic, which are present in waxes. Characteristics of synthesized acids are tabulated. 20 refs.
Does object view influence the scene consistency effect?
Sastyin, Gergo; Niimi, Ryosuke; Yokosawa, Kazuhiko
2015-04-01
Traditional research on the scene consistency effect only used clearly recognizable object stimuli to show mutually interactive context effects for both the object and background components on scene perception (Davenport & Potter in Psychological Science, 15, 559-564, 2004). However, in real environments, objects are viewed from multiple viewpoints, including an accidental, hard-to-recognize one. When the observers named target objects in scenes (Experiments 1a and 1b, object recognition task), we replicated the scene consistency effect (i.e., there was higher accuracy for the objects with consistent backgrounds). However, there was a significant interaction effect between consistency and object viewpoint, which indicated that the scene consistency effect was more important for identifying objects in the accidental view condition than in the canonical view condition. Therefore, the object recognition system may rely more on the scene context when the object is difficult to recognize. In Experiment 2, the observers identified the background (background recognition task) while the scene consistency and object views were manipulated. The results showed that object viewpoint had no effect, while the scene consistency effect was observed. More specifically, the canonical and accidental views both equally provided contextual information for scene perception. These findings suggested that the mechanism for conscious recognition of objects could be dissociated from the mechanism for visual analysis of object images that were part of a scene. The "context" that the object images provided may have been derived from its view-invariant, relatively low-level visual features (e.g., color), rather than its semantic information. PMID:25522833
View Combination: A Generalization Mechanism for Visual Recognition
ERIC Educational Resources Information Center
Friedman, Alinda; Waller, David; Thrash, Tyler; Greenauer, Nathan; Hodgson, Eric
2011-01-01
We examined whether view combination mechanisms shown to underlie object and scene recognition can integrate visual information across views that have little or no three-dimensional information at either the object or scene level. In three experiments, people learned four "views" of a two dimensional visual array derived from a three-dimensional…
Li, Liangjun; Wang, Ying; Gu, Xin; Yang, Qipeng; Zhao, Xuebo
2016-07-01
The development of functional porous carbon with high CO2 /N2 selectivity is of great importance for CO2 capture. In this paper, a type of porous carbon with doped pyridinic sites (termed MOFC) was prepared from the carbonization of a pyridyl-ligand based MOF. Four MOFCs derived from different carbonizing temperatures were prepared. Structural studies revealed high contents of pyridinic-N groups and nearly the same pore-size distributions for these MOFCs. Gas-sorption studies revealed outstanding CO2 uptake at low pressures and room temperature. Owing to the high content of pyridinic-N groups, the CO2 /N2 selectivity on these MOFCs exhibits values of about 40-50, which are among the top values in carbon materials. Further correlation studies demonstrated that the CO2 /N2 selectivities show a positive linear relationship with the surface density of pyridinic-N groups, thus validating the synergistic effect of the doped pyridinic-N groups on CO2 adsorption selectivity. PMID:27146096
Internationalisation of Higher Education in Hong Kong
ERIC Educational Resources Information Center
Pretor Fok, Wai-kei
2007-01-01
With a view that internationalisation is an interactive response to globalisation, this paper examines the internationalising activities in the higher education sector, and in particular, the Hong Kong higher education sector. Four main areas are covered: (a) internationalising staff and students, (b) building an international network, (c)…
Address to the Statewide Higher Education Officers.
ERIC Educational Resources Information Center
Judge, Thomas L.
Perspectives on higher education in Montana as viewed by the governor are presented. After briefly noting historical trends in Montana and the United States regarding education, concerns and trends in higher education are noted as follows: accountability to the public for how tax dollars are spent; evidence that there will be decreased demand for…
Multi-View Intact Space Learning.
Xu, Chang; Tao, Dacheng; Xu, Chao
2015-12-01
It is practical to assume that an individual view is unlikely to be sufficient for effective multi-view learning. Therefore, integration of multi-view information is both valuable and necessary. In this paper, we propose the Multi-view Intact Space Learning (MISL) algorithm, which integrates the encoded complementary information in multiple views to discover a latent intact representation of the data. Even though each view on its own is insufficient, we show theoretically that by combing multiple views we can obtain abundant information for latent intact space learning. Employing the Cauchy loss (a technique used in statistical learning) as the error measurement strengthens robustness to outliers. We propose a new definition of multi-view stability and then derive the generalization error bound based on multi-view stability and Rademacher complexity, and show that the complementarity between multiple views is beneficial for the stability and generalization. MISL is efficiently optimized using a novel Iteratively Reweight Residuals (IRR) technique, whose convergence is theoretically analyzed. Experiments on synthetic data and real-world datasets demonstrate that MISL is an effective and promising algorithm for practical applications. PMID:26539856
Higher order stationary subspace analysis
NASA Astrophysics Data System (ADS)
Panknin, Danny; von Bünau, Paul; Kawanabe, Motoaki; Meinecke, Frank C.; Müller, Klaus-Robert
2016-03-01
Non-stationarity in data is an ubiquitous problem in signal processing. The recent stationary subspace analysis procedure (SSA) has enabled to decompose such data into a stationary subspace and a non-stationary part respectively. Algorithmically only weak non- stationarities could be tackled by SSA. The present paper takes the conceptual step generalizing from the use of first and second moments as in SSA to higher order moments, thus defining the proposed higher order stationary subspace analysis procedure (HOSSA). The paper derives the novel procedure and shows simulations. An obvious trade-off between the necessity of estimating higher moments and the accuracy and robustness with which they can be estimated is observed. In an ideal setting of plenty of data where higher moment information is dominating our novel approach can win against standard SSA. However, with limited data, even though higher moments actually dominate the underlying data, still SSA may arrive on par.
Energy Science and Technology Software Center (ESTSC)
2007-09-25
The ThreatView project is based on our prior work with the existing ParaView open-source scientific visualization application. Where ParaView provides a grapical client optimized scientific visualization over the VTK parallel client server architecture, ThreatView provides a client optimized for more generic visual analytics over the same architecture. Because ThreatView is based on the VTK parallel client-server architecture, data sources can reside on remote hosts, and processing and rendering can be performed in parallel. As seenmore » in Fig. 1, ThreatView provides four main methods for visualizing data: Landscape View, which displays a graph using a landscape metaphor where clusters of graph nodes produce "hills" in the landscape; Graph View, which displays a graph using a traditional "ball-and-stick" style; Table View, which displays tabular data in a standard spreadsheet; and Attribute View, which displays a tabular "histogram" of input data - for a selected table column, the Attribute View displays each unique value within the column, and the number of times that value appears in the data. There are two supplemental view types: Text View, which displays tabular data one-record-at-a-time; and the Statistics View, which displays input metadata, such as the number of vertices and edges in a graph, the number of rows in a table, etc.« less
Shead, Timothy M.; Wylie, Brian
2007-09-25
The ThreatView project is based on our prior work with the existing ParaView open-source scientific visualization application. Where ParaView provides a grapical client optimized scientific visualization over the VTK parallel client server architecture, ThreatView provides a client optimized for more generic visual analytics over the same architecture. Because ThreatView is based on the VTK parallel client-server architecture, data sources can reside on remote hosts, and processing and rendering can be performed in parallel. As seen in Fig. 1, ThreatView provides four main methods for visualizing data: Landscape View, which displays a graph using a landscape metaphor where clusters of graph nodes produce "hills" in the landscape; Graph View, which displays a graph using a traditional "ball-and-stick" style; Table View, which displays tabular data in a standard spreadsheet; and Attribute View, which displays a tabular "histogram" of input data - for a selected table column, the Attribute View displays each unique value within the column, and the number of times that value appears in the data. There are two supplemental view types: Text View, which displays tabular data one-record-at-a-time; and the Statistics View, which displays input metadata, such as the number of vertices and edges in a graph, the number of rows in a table, etc.
Kolattukudy, P E
2001-01-01
Polyesters occur in higher plants as the structural component of the cuticle that covers the aerial parts of plants. This insoluble polymer, called cutin, attached to the epidermal cell walls is composed of interesterified hydroxy and hydroxy epoxy fatty acids. The most common chief monomers are 10,16-dihydroxy C16 acid, 18-hydroxy-9,10 epoxy C18 acid, and 9,10,18-trihydroxy C18 acid. These monomers are produced in the epidermal cells by omega hydroxylation, in-chain hydroxylation, epoxidation catalyzed by P450-type mixed function oxidase, and epoxide hydration. The monomer acyl groups are transferred to hydroxyl groups in the growing polymer at the extracellular location. The other type of polyester found in the plants is suberin, a polymeric material deposited in the cell walls of a layer or two of cells when a plant needs to erect a barrier as a result of physical or biological stress from the environment, or during development. Suberin is composed of aromatic domains derived from cinnamic acid, and aliphatic polyester domains derived from C16 and C18 cellular fatty acids and their elongation products. The polyesters can be hydrolyzed by pancreatic lipase and cutinase, a polyesterase produced by bacteria and fungi. Catalysis by cutinase involves the active serine catalytic triad. The major function of the polyester in plants is as a protective barrier against physical, chemical, and biological factors in the environment, including pathogens. Transcriptional regulation of cutinase gene in fungal pathogens is being elucidated at a molecular level. The polyesters present in agricultural waste may be used to produce high value polymers, and genetic engineering might be used to produce large quantities of such polymers in plants. PMID:11217409
View factors of cylindrical spiral surfaces
NASA Astrophysics Data System (ADS)
Lebedev, Vladimir A.; Solovjov, Vladimir P.
2016-03-01
Analytical expressions are presented for the view factors (radiative configuration factors) associated with the flat right cylindrical spiral surface. Such cylindrical spiral systems are widely applied as electrical resistance heating elements for lighting devices, electronic radio tubes, high-speed gas flow heaters, and other appliances used for scientific, industrial and domestic purposes. Derivation of the view factors is based on the invariant principles and the results presented in Lebedev (2000, 2003,1988) [1-3].
Viewing angle analysis of integral imaging
NASA Astrophysics Data System (ADS)
Wang, Hong-Xia; Wu, Chun-Hong; Yang, Yang; Zhang, Lan
2007-12-01
Integral imaging (II) is a technique capable of displaying 3D images with continuous parallax in full natural color. It is becoming the most perspective technique in developing next generation three-dimensional TV (3DTV) and visualization field due to its outstanding advantages. However, most of conventional integral images are restricted by its narrow viewing angle. One reason is that the range in which a reconstructed integral image can be displayed with consistent parallax is limited. The other is that the aperture of system is finite. By far many methods , an integral imaging method to enhance the viewing angle of integral images has been proposed. Nevertheless, except Ren's MVW (Maximum Viewing Width) most of these methods involve complex hardware and modifications of optical system, which usually bring other disadvantages and make operation more difficult. At the same time the cost of these systems should be higher. In order to simplify optical systems, this paper systematically analyzes the viewing angle of traditional integral images instead of modified ones. Simultaneously for the sake of cost the research was based on computer generated integral images (CGII). With the analysis result we can know clearly how the viewing angle can be enhanced and how the image overlap or image flipping can be avoided. The result also promotes the development of optical instruments. Based on theoretical analysis, preliminary calculation was done to demonstrate how the other viewing properties which are closely related with the viewing angle, such as viewing distance, viewing zone, lens pitch, and etc. affect the viewing angle.
NASA Technical Reports Server (NTRS)
2002-01-01
This true-color image over the North Pole was acquired by the MODerate-resolution Imaging Spectroradiometer (MODIS), flying aboard the Terra spacecraft, on May 5, 2000. The scene was received and processed by Norway's MODIS Direct Broadcast data receiving station, located in Svalbard, within seconds of photons hitting the sensor's detectors. (Click for more details about MODIS Direct Broadcast data.) In this image, the sea ice appears white and areas of open water, or recently refrozen sea surface, appear black. The irregular whitish shapes toward the bottom of the image are clouds, which are often difficult to distinguish from the white Arctic surface. Notice the considerable number of cracks, or 'leads,' in the ice that appear as dark networks of lines. Throughout the region within the Arctic Circle leads are continually opening and closing due to the direction and intensity of shifting wind and ocean currents. Leads are particularly common during the summer, when temperatures are higher and the ice is thinner. In this image, each pixel is one square kilometer. Such true-color views of the North Pole are quite rare, as most of the time much of the region within the Arctic Circle is cloaked in clouds. Image by Allen Lunsford, NASA GSFC Direct Readout Laboratory; Data courtesy Tromso receiving station, Svalbard, Norway
Li, A S
1995-12-01
The personal experiences at the Beijing Fourth World Conference on Women and the Nongovernmental Organization (NGO) Forum were described by a Chinese American veterinarian. The author became aware that women were primarily the persons living in poverty in the world. Business and government appeared more concerned with economic growth. As a consequence, developed countries with 20% of world population consume 80% of the world's resources. The privilege of money secures a position of power in the world, power to buy up the resources of the world. This process is unsustainable and inequitable. Women are viewed as key players in shifting the balance in favor of a higher quality of life. The NGO workshops on Women in Livestock Development (WILD) was run by women veterinarians, who worked at the local level with women in poor areas. WILD operates out of offices in Arkansas in the USA. WILD women work in Sichuan, China, among the Han and Tibetans in increasing family income through heifer and livestock production. Conference participants from WILD programs talked about their experiences with increased income and loans to other women. The World Women's Veterinary Association members, who attended the conference, visited a small animal clinic in Beijing run by the Agriculture Ministry, and Beijing Agricultural University and its Veterinary Teaching Hospital. Demonstrations were given of small animal acupuncture. The author found the conference to be a success and found that press reports misrepresented the energy generated by the meeting. PMID:12346904
Canonical structure of higher derivative gravity in 3D
Guellue, Ibrahim; Sisman, Tahsin Cagri; Tekin, Bayram
2010-05-15
We give an explicitly gauge-invariant canonical analysis of linearized quadratic gravity theories in three dimensions for both flat and de Sitter backgrounds. In flat backgrounds, we also study the effects of the gravitational Chern-Simons term, include the sources, and compute the weak field limit as well as scattering between spinning massive particles.
Spherically symmetric solutions in higher-derivative gravity
NASA Astrophysics Data System (ADS)
Lü, H.; Perkins, A.; Pope, C. N.; Stelle, K. S.
2015-12-01
Extensions of Einstein gravity with quadratic curvature terms in the action arise in most effective theories of quantized gravity, including string theory. This article explores the set of static, spherically symmetric and asymptotically flat solutions of this class of theories. An important element in the analysis is the careful treatment of a Lichnerowicz-type "no-hair" theorem. From a Frobenius analysis of the asymptotic small-radius behavior, the solution space is found to split into three asymptotic families, one of which contains the classic Schwarzschild solution. These three families are carefully analyzed to determine the corresponding numbers of free parameters in each. One solution family is capable of arising from coupling to a distributional shell of matter near the origin; this family can then match onto an asymptotically flat solution at spatial infinity without encountering a horizon. Another family, with horizons, contains the Schwarzschild solution but includes also non-Schwarzschild black holes. The third family of solutions obtained from the Frobenius analysis is nonsingular and corresponds to "vacuum" solutions. In addition to the three families identified from near-origin behavior, there are solutions that may be identified as "wormholes," which can match symmetrically onto another sheet of spacetime at finite radius.
Higher Education and the Steady State. ERIC/Higher Education Research Report No. 4 1974.
ERIC Educational Resources Information Center
Leslie, Larry L.; Miller, Howard F., Jr.
This paper examines the no-growth phenomenon in higher education. A framework is presented for viewing what is occurring in higher education as it seeks to resume a dynamic state of growth. Borrowing from Schumpeter's five categories of innovations by which business firms seek to gain a competitive edge over their rivals, an analytical framework…
Higher Education Exchange, 2011
ERIC Educational Resources Information Center
Brown, David W., Ed.; Witte, Deborah, Ed.
2011-01-01
"Higher Education Exchange" publishes case studies, analyses, news, and ideas about efforts within higher education to develop more democratic societies. Contributors to this issue of the "Higher Education Exchange" examine whether institutions of higher learning are doing anything to increase the capacity of citizens to shape their future.…
Higher Education Exchange, 2012
ERIC Educational Resources Information Center
Brown, David W., Ed.; Witte, Deborah, Ed.
2012-01-01
"Higher Education Exchange" publishes case studies, analyses, news, and ideas about efforts within higher education to develop more democratic societies. Contributors to this issue of the "Higher Education Exchange" examine whether institutions of higher learning are doing anything to increase the capacity of citizens to shape their future.…
Higher Education Exchange, 2014
ERIC Educational Resources Information Center
Brown, David W., Ed.; Witte, Deborah, Ed.
2014-01-01
Research shows that not only does higher education not see the public; when the public, in turn, looks at higher education, it sees mostly malaise, inefficiencies, expense, and unfulfilled promises. Yet, the contributors to this issue of the "Higher Education Exchange" tell of bright spots in higher education where experiments in working…
Higher Education Exchange, 2008
ERIC Educational Resources Information Center
Brown, David W., Ed.; Witte, Deborah, Ed.
2008-01-01
"Higher Education Exchange" publishes case studies, analyses, news, and ideas about efforts within higher education to develop more democratic societies. Contributors to this issue of the "Higher Education Exchange" examine whether institutions of higher learning are doing anything to increase the capacity of citizens to shape their future.…
Higher Education Exchange, 2010
ERIC Educational Resources Information Center
Brown, David W., Ed.; Witte, Deborah, Ed.
2010-01-01
"Higher Education Exchange" publishes case studies, analyses, news, and ideas about efforts within higher education to develop more democratic societies. Contributors to this issue of the "Higher Education Exchange" examine whether institutions of higher learning are doing anything to increase the capacity of citizens to shape their future.…
Occupational Information. A Career Guidance View.
ERIC Educational Resources Information Center
Wolfbein, Seymour L.
This book deals not with the administrative or information searching processes related to the guidance function of providing occupational information, but with the substantive information itself. It presents a contemporary view of values, trends, and principles, derived primarily from statistical information describing the current world of work.…
Views of wireless network systems.
Young, William Frederick; Duggan, David Patrick
2003-10-01
Wireless networking is becoming a common element of industrial, corporate, and home networks. Commercial wireless network systems have become reliable, while the cost of these solutions has become more affordable than equivalent wired network solutions. The security risks of wireless systems are higher than wired and have not been studied in depth. This report starts to bring together information on wireless architectures and their connection to wired networks. We detail information contained on the many different views of a wireless network system. The method of using multiple views of a system to assist in the determination of vulnerabilities comes from the Information Design Assurance Red Team (IDART{trademark}) Methodology of system analysis developed at Sandia National Laboratories.
NASA Astrophysics Data System (ADS)
Battiston, Stefano; Caldarelli, Guido; Georg, Co-Pierre; May, Robert; Stiglitz, Joseph
2013-03-01
The intrinsic complexity of the financial derivatives market has emerged as both an incentive to engage in it, and a key source of its inherent instability. Regulators now faced with the challenge of taming this beast may find inspiration in the budding science of complex systems.
A common-view disciplined oscillator
Lombardi, Michael A.; Dahlen, Aaron P.
2010-05-15
This paper describes a common-view disciplined oscillator (CVDO) that locks to a reference time scale through the use of common-view global positioning system (GPS) satellite measurements. The CVDO employs a proportional-integral-derivative controller that obtains near real-time common-view GPS measurements from the internet and provides steering corrections to a local oscillator. A CVDO can be locked to any time scale that makes real-time common-view data available and can serve as a high-accuracy, self-calibrating frequency and time standard. Measurement results are presented where a CVDO is locked to UTC(NIST), the coordinated universal time scale maintained at the National Institute of Standards and Technology in Boulder, Colorado.
Higher Education Management. The Key Elements.
ERIC Educational Resources Information Center
Warner, David, Ed.; Palfreyman, David, Ed.
This book presents the views of 15 individual authors on the principles of management in higher education from a British perspective. Preliminary material includes brief biographical sketches of each contributing author and a list of selected abbreviations. Individual chapters are: (1) "Setting the Scene" (David Palfreyman and David Warner); (2)…
Peer Learning for Change in Higher Education
ERIC Educational Resources Information Center
Hilsdon, John
2014-01-01
This paper draws upon small scale, qualitative research at a UK university to present a Learning Development (LD) perspective on peer learning. This approach is offered as a lens for exploring social aspects of learning, cultural change in higher education and implications for pedagogy and policy. Views of a small group of peer learning leaders…
Embedding Quality: The Challenges for Higher Education
ERIC Educational Resources Information Center
Lomas, Laurie
2004-01-01
This paper reviews recent research, literature and the views of a small sample of senior managers and academics in English higher education institutions on the challenges associated with embedding quality. When implemented by a university, quality enhancement models such as total quality management and the European Foundation for Quality…
Student Perspectives on Quality in Higher Education
ERIC Educational Resources Information Center
Jungblut, Jens; Vukasovic, Martina; Stensaker, Bjørn
2015-01-01
The study provides an insight into student perspectives on quality in higher education, using Harvey and Green conceptualizations as the point of departure, and exploring the linkages between the views on quality, the developments of the Bologna Process and related national reforms, as well as students' motivation for and expectations from higher…
Mapping Efficient Communication Networks in Higher Education.
ERIC Educational Resources Information Center
Lubinescu, E. S.; Prabhu, R. P.; Terheggen, S. L.
Some perspectives are presented that help explain communication networks in institutions of higher education and the factors that impede or facilitate their efficient functioning. The first theory that informs this exploration is that of K. Wieck (1969), which states that communication can be viewed through the lens of "sensemaking." The…
Grade Inflation: Academic Standards in Higher Education
ERIC Educational Resources Information Center
Hunt, Lester H., Ed.
2008-01-01
This book provides a provocative look at the issues and controversies surrounding grade inflation, and, more generally, grading practices in American higher education. The contributors confront the issues from a number of different disciplines and varying points of view. Topics explored include empirical evidence for and against the claim that…
Quality and Standards in Higher Education
ERIC Educational Resources Information Center
Williams, Peter
2010-01-01
Quality and standards in higher education is a tricky topic, but one that will not go away. Everyone has a view, but it is rarely informed by fact. The subject is particularly difficult for several reasons. Perhaps the most important of these is the lack of any generally agreed definition of what quality and standards are. In this article, the…
Moral Reasoning and Higher-Education Policy
ERIC Educational Resources Information Center
McPherson, Michael S.; Schapiro, Morton Owen
2007-01-01
Many people in higher education think that "values talk" should be reserved for important ceremonial occasions, like commencements and reunions, or for remarks after a major scandal. In their view, values should take a back seat to the pragmatic reality of empirical evidence. But, in reality, every interesting problem of policy or practice depends…
ERIC Educational Resources Information Center
Srinivasan, A. R.; Olson, Wilma K.
1989-01-01
The illustration of molecular structures by means of stereo pairs (to project three-dimensional views of two-dimensional representations) has been common practice in periodicals, slide presentations, and books. Describes the stereo triptych and multiply rotated stereo views with diagrams and discusses the use of them. (YP)
Atmospheric Science Data Center
2013-04-01
... A software tool for visualization of MISR and AirMISR data files, misr_view , was developed by NASA's Jet Propulsion Laboratory. ... Guide, is available for download free of charge from the Open Channel Foundation . misr_view is a graphical user interface display ...
Erbacher, Robert; Frincke, Deb
2007-07-02
Coordinated views have proven critical to the development of effective visualization environments. This results from the fact that a single view or representation of the data cannot show all of the intricacies of a given data set. Additionally, users will often need to correlate more data parameters than can effectively be integrated into a single visual display. Typically, development of multiple-linked views results in an adhoc configuration of views and associated interactions. The hierarchical model we are proposing is geared towards more effective organization of such environments and the views they encompass. At the same time, this model can effectively integrate much of the prior work on interactive and visual frameworks. Additionally, we expand the concept of views to incorporate perceptual views. This is related to the fact that visual displays can have information encoded at various levels of focus. Thus, a global view of the display provides overall trends of the data while focusing in on individual elements provides detailed specifics. By integrating interaction and perception into a single model, we show how one impacts the other. Typically, interaction and perception are considered separately, however, when interaction is being considered at a fundamental level and allowed to direct/modify the visualization directly we must consider them simultaneously and how they impact one another.
ERIC Educational Resources Information Center
Bennett, Robert B., Jr.
2010-01-01
Legal studies faculty need to take the long view in their academic and professional lives. Taking the long view would seem to be a cliched piece of advice, but too frequently legal studies faculty, like their students, get focused on meeting the next short-term hurdle--getting through the next class, grading the next stack of papers, making it…
Special Higher Education Bibliography.
ERIC Educational Resources Information Center
Weinberg, Meyer
1982-01-01
Cites works relevant to the higher education of Blacks and minority group members. Lists references alphabetically under the following headings: (1) financial aid on the campus; (2) Chicanos in higher education; and (3) race and equality on California campuses. (GC)
The Higher Education Enterprise.
ERIC Educational Resources Information Center
Ottinger, Cecilia A.
1991-01-01
Higher education not only contributes to the development of the human resources and intellectual betterment of the nation but is also a major economic enterprise. This research brief reviews and highlights data on the size and growth of higher education and illustrates how higher education institutions are preparing the future labor force. It…
Spotlight on Higher Education.
ERIC Educational Resources Information Center
Klinger, Donna; Iwanowski, Jay
1997-01-01
A number of current issues and initiatives in higher education are highlighted, including impending reauthorization of the Higher Education Act, the need for advocacy of higher education in public policy arenas, a University of Florida program combining accountability and institutional autonomy, and institutional compliance with nonresident alien…
Higher Education Exchange, 2007
ERIC Educational Resources Information Center
Brown, David W., Ed.; Witte, Deborah, Ed.
2007-01-01
"Higher Education Exchange" publishes case studies, analyses, news, and ideas about efforts within higher education to develop more democratic societies. Contributors to this issue of the "Higher Education Exchange" discuss the concept of growing public scholars; each contribution incorporates a student component. Articles include: (1) "Foreword"…
GNSS-derived Geocenter Coordinates Viewed by Perturbation Theory
NASA Astrophysics Data System (ADS)
Meindl, Michael; Beutler, Gerhard; Thaller, Daniela; Dach, Rolf; Jäggi, Adrian; Rothacher, Markus
2013-04-01
Time series of geocenter coordinates were determined with data of the two global navigation satellite systems (GNSS) GPS and GLONASS. The data was recorded in the years 2008-2011 by a global network of 92 combined GPS/GLONASS receivers. Two types of solutions were generated for each system, one including the estimation of geocenter coordinates and one without these parameters. A fair agreement for GPS and GLONASS estimates was found in the x- and y-coordinate series of the geocenter. Artifacts do, however, clearly show up in the z-coordinate. Large periodic variations in the GLONASS geocenter z-coordinates of about 40 cm peak-to-peak are related to the maximum elevation angles of the Sun above/below the orbital planes of the satellite system. A detailed analysis revealed that these artifacts are almost uniquely governed by the differences of the estimates of direct solar radiation pressure (SRP) in the two solution series (with and without geocenter estimation). This effect can be explained by first-order perturbation theory of celestial mechanics. The relation between the geocenter z-coordinate and the corresponding SRP parameters will be presented. Our theory is applicable to all satellite observing techniques. In addition to GNSS, we applied it to satellite laser ranging (SLR) solutions based on LAGEOS observations. The correlation between geocenter and SRP parameters is not a critical issue for SLR, because these parameters do not have to be estimated. This basic difference between SLR and GNSS analyses explains why SLR is an excellent tool to determine geodetic datum parameters like the geocenter coordinates. The correlation between orbit parameters and the z-component of the geocenter is not limited to a particular orbit model, e.g., that of CODE. The issue should be studied for alternative (e.g., box-wing) models: As soon as non-zero mean values (over one revolution) of the out-of-plane force component exist, one has to expect biased geocenter estimates. The insights gained here should be seriously taken into account in the orbit modeling discussion currently taking place within the IGS.
Generalized structure of higher order nonclassicality
NASA Astrophysics Data System (ADS)
Verma, Amit; Pathak, Anirban
2010-02-01
A generalized notion of higher order nonclassicality (in terms of higher order moments) is introduced. Under this generalized framework of higher order nonclassicality, conditions of higher order squeezing and higher order subpoissonian photon statistics are derived. A simpler form of the Hong-Mandel higher order squeezing criterion is derived under this framework by using an operator ordering theorem introduced by us in [A. Pathak, J. Phys. A 33 (2000) 5607]. It is also generalized for multi-photon Bose operators of Brandt and Greenberg. Similarly, condition for higher order subpoissonian photon statistics is derived by normal ordering of higher powers of number operator. Further, with the help of simple density matrices, it is shown that the higher order antibunching (HOA) and higher order subpoissonian photon statistics (HOSPS) are not the manifestation of the same phenomenon and consequently it is incorrect to use the condition of HOA as a test of HOSPS. It is also shown that the HOA and HOSPS may exist even in absence of the corresponding lower order phenomenon. Binomial state, nonlinear first order excited squeezed state (NLESS) and nonlinear vacuum squeezed state (NLVSS) are used as examples of quantum state and it is shown that these states may show higher order nonclassical characteristics. It is observed that the Binomial state which is always antibunched, is not always higher order squeezed and NLVSS which shows higher order squeezing does not show HOSPS and HOA. The opposite is observed in NLESS and consequently it is established that the HOSPS and HOS are two independent signatures of higher order nonclassicality.
Cosmological attractor models and higher curvature supergravity
NASA Astrophysics Data System (ADS)
Cecotti, Sergio; Kallosh, Renata
2014-05-01
We study cosmological α-attractors in superconformal/supergravity models, where α is related to the geometry of the moduli space. For α = 1 attractors [1] we present a generalization of the previously known manifestly superconformal higher curvature supergravity model [2]. The relevant standard 2-derivative supergravity with a minimum of two chiral multiplets is shown to be dual to a 4-derivative higher curvature supergravity, where in general one of the chiral superfields is traded for a curvature superfield. There is a degenerate case when both matter superfields become non-dynamical and there is only a chiral curvature superfield, pure higher derivative supergravity. Generic α-models [3] interpolate between the attractor point at α = 0 and generic chaotic inflation models at large α, in the limit when the inflaton moduli space becomes flat. They have higher derivative duals with the same number of matter fields as the original theory or less, but at least one matter multiplet remains. In the context of these models, the detection of primordial gravity waves will provide information on the curvature of the inflaton submanifold of the Kähler manifold, and we will learn if the inflaton is a fundamental matter multiplet, or can be replaced by a higher derivative curvature excitation.
ERIC Educational Resources Information Center
Willard, Timothy; And Others
1984-01-01
An overview of topics discussed at the World View '84 conference, sponsored by the World Future Society, is provided. Topics include technology, the economy, the Third World, the environment, world order, and outer space. (RM)
The Kepler mission will be looking continuously at over 100,000 stars in one region of the sky, in the Cygnus and Lyra constellations. The field of view is extremely large for an astronomical teles...
Quality in Higher Education: United Arab Emirates Perspective
ERIC Educational Resources Information Center
Soomro, Tariq Rahim; Ahmad, Reyaz
2012-01-01
Quality in higher education is the major concern among researchers. Managing quality in higher education in a multicultural population with different approaches is not only challenging but an uphill task. This paper will focus on quality concern in higher education keeping in view, the United Arab Emirates (UAE) perspectives. A model to maintain…
33. VIEW LOOKING NORTHNORTHWEST AT THE DENNIS HOTEL (PARTIAL VIEW ...
33. VIEW LOOKING NORTH-NORTHWEST AT THE DENNIS HOTEL (PARTIAL VIEW OF THE BLENHEIM HOTEL) - Marlborough, Blenheim & Dennis Hotels (aerial views), Between Park Place, Michigan Avenue & Boardwalk, Atlantic City, Atlantic County, NJ
Development of a dual-view endoscope system
NASA Astrophysics Data System (ADS)
Sekiya, Takaomi; Ito, Eiichi; Kanai, Moriyasu; Matsumoto, Mitsuhiro
2006-02-01
We demonstrate a new endoscope system for laparoscopic surgery that provides two different views simultaneously. One is a 'wide view' and the other is an 'enlarged view' derived from the wide view with an optical image-shifting mechanism. By using this endoscope, surgeons can observe a surgical area as an enlarged view without moving or rotating the endoscope. Moreover, the wide view is useful for examining the outside of a surgical area. They can move the enlarged view within the area of the wide view by using the image-shifting mechanism. This system consists of a rigid scope and a 'zoom unit.' The rigid scope includes a set of optical lenses for the wide view angle (120 degrees) and light-guide fibers built in for illumination. These fibers are connected to a light source directly. The zoom unit includes imaging optical elements and two CCD cameras. In the zoom unit, an image provided by the rigid scope is divided into two ways by a half-mirror. One image is captured by the first CCD camera with relay lenses for a wide view. The other passes through a Porro prism (II), which is used to shift the enlarged view vertically and horizontally, and zoom lenses with a three variable power. Then, the image is captured by the second CCD camera for an enlarged view. A working distance between the tip of the rigid scope and the surface of viscera is 100mm that is sufficient for surgical operation.