bluuebunny/crossref_metadata_2025 huggingface dataset:
Identifiability of distributed parameters for high-order quasi-linear differential equations
Authors: Lesnic D. , Elliott L. , Ingham D. B.
Published: September 2013

- Necessary and/or sufficient conditions for the identifiability, or nonidentifiability, of coefficients associated with a general class of high-order, quasi-linear (partial) differential equations are established.
Stability and convergence of the wavelet-Galerkin method for the sideways heat equation
Authors: Regińska T. , Eldén L.
Published: September 2013

- We consider an inverse heat conduction problem, the Sideways Heat Equation. This is a Cauchy problem for the heat equation in a quarter-plane, with data given along the line x = 1, where the solution is sought for 0 ≤ x < 1. The problem is ill-posed, in the sense that the solution (if it exists) does not depend continuously on the data. We discuss the stability and convergence properties of the wavelet- Galerkin method for solving the sideways heat equation. The wavelets are of Meyer type that have compact support in frequency space. Previous stability results for this method were suboptimal. We show that with additional assumptions concerning the smoothness of the solution, and concerning the definition of the wavelets, we can obtain almost optimal error estimates.
On the inverse problem of determining a connection on a vector bundle
Authors: Sharafutdinov V. A.
Published: September 2013

- We consider the problem of determining a connection on a vector bundle over a compact Riemannian manifold with boundary from the known parallel transport between boundary points along geodesics. The main result is the local uniqueness theorem: if two connections ∇' and ∇'' are C-close to a given connection ∇ whose curvature tensor is sufficiently small, then the coincidence of parallel transports with respect to ∇' and ∇'' implies the existence of an automorphism of the bundle which is identical on the boundary and transforms ∇' to ∇'' . A linearized version of the problem is also considered.
An iterated version of Lavrent’iev’s method for ill-posed equations with approximately specified data
Authors: Thamban Nair M.
Published: September 2013

- An iterated version of the Lavrentiev’s method, in the setting of a Banach space, is suggested for obtaining stable approximate solutions for the ill-posed operator equation Au = v, when the data A and v are known only approximately. In the setting of a Hilbert space with appropriate a priori parameter choice, the suggested procedure yields order optimal error estimates. An iterated version of Tikhonov regularization yielding order optimal error estimate is a special case of the procedure. The assumption on the approximating operators show that the finite dimensional system arising out of it would be of smaller size for larger iterates. This aspect is compared with an assumption of [3] for a degenerate kernel method for integral equations of the first kind.
An inverse problem for orthotropic medium
Authors: Seydou F.
Published: September 2013

- In this paper we discuss an inverse problem in which we try to determine the refractive index corresponding to the scattering of electromagnetic waves by an inhomogeneous orthotropic medium, which is a special case of anisotropic medium, from far field data. In particular we shall be treating the use of the dual space method (due to Colton and Monk) to reconstruct the refractive index.
Necessary and sufficient conditions of convergence of finite-dimensional approximations for L-regularized solutions of operator equations
Authors: Tanana V.P.
Published: September 2013

- In this paper we consider the finite-dimensional approximations for L-regularized solutions in the Hilbert space [4].

Necessary and sufficient conditions on the independent disturbances of operators A and L which provide the convergence of finite-dimensional approximations are defined in Theorem 2 (the main statement of the paper).

Obtained results essentially generalize results of [2, 3] and in the sequel can be used for development of finite-difference approximation methods for solving integrodifferential equations [2, 4].
Boundary shape identification in two-dimensional electrostatic problems using SQUIDs
Authors: Banks H. T. , Kojima F.
Published: September 2013

- This paper is concerned with a quantitative nondestructive evaluation of conductors using superconducting quantum interference devices (SQUIDs). A measurement system is described for an electrical potential problem with an unknown boundary. Domain identification is discussed within the theoretical framework of parameter estimation problem for the electrostatic field analysis. Applying the method of mappings to the problem considered here, we present computational methods, including theoretical convergence results for the associated finite dimensional problem identification techniques.
An identification problem related to a parabolic integrodifferential equation with non commuting spatial operators
Authors: Colombo F. , Lorenzi A.
Published: September 2013

- In this paper we prove a (local in time) existence and uniqueness theorem for the identification of a memory kernel h entering a parabolic integrodifferential equation with non commuting operators, related to a convex cylindrical domain, when the coefficient h is assumed to depend on time and one space variable.
Numerical solution of the Cauchy problem in plane elastostatics
Authors: Kobayashi K.
Published: September 2013

- A variational approach is presented for numerical identification of the boundary conditions in solution of the Cauchy problem governed by the Navier equations in two-dimensional elasticity. The Cauchy problem in elastostatics is featured by simultaneously prescribed displacement and traction on a part of the boundary of an elastic body. The boundary data may contain some noise. The problem can be reformulated as a minimization problem of a functional with constraints, then the minimization problem is recast into successive primary and adjoint boundary value problems with no constraints in the corresponding plane elasticity problem. Two variational formulations, i. e., displacement approach and traction approach, are described. For an approximate solution of the elasticity problems, the conventional direct boundary element method is applied. Through simple examples, it is shown that our variational approaches are convergent and the proposed numerical process is stable.
An inverse problem of ocean acoustics
Authors: Ramm A. G.
Published: September 2013

Let

(1) u(x1, 0) = 0, uʹ(x1, 1) = 0, (2) where u = u(x1, z), x1 := (x1, x2), r := |x1|, x3 := z, uʹ = ∂u/∂z, δ(r) is the delta-function, n(z) is the refraction coefficient, which is assumed to be a real-valued integrable function, k > 0 is a fixed wavenumber. The solution to (1)-(2) is selected by the limiting absorption principle. It is proved that if f(z) = δ(z − 1), then n(z) is uniquely determined by the data u(x1, 1) known ∀x1 ∈ ℝ2. Comments are made concerning the earlier study of a similar problem in the literature.
A preconditioner for least-squares distributed parameter estimation
Authors: Wade J.G.
Published: September 2013

- We develop a preconditioner for a family (G + αA)q = b of symmetric positive definite matrices arising in numerical treatment of distributed parameter inverse problems of the form Kq
= ￣z via least-squares with total variation. Here, q and b are discrete approximations of functions in L
2(Ω), Ω ⊂ Rn, n ≥ 2. The matrix G is a discrete approximation of K∗K, the matrix A is an approximation of a self-adjoint elliptic operator arising from the regularization.

Depending on the level of discretization, the size of the system (G+αA)q = b may be very large, so that iterative methods such as preconditioned conjugate gradients may be necessary. However, although A is sparse, the matrix G is generally dense, so that sparse-matrix preconditioning techniques are not appropriate for this problem.

We develop a new preconditioner for this problem which is based on a low-rank, low-storage approximation of G. This approximation is built from information acquired in the course of iterations. The construction of the preconditioner and some mathematical analysis are presented, together with a detailed numerical example involving a parabolic PDE in a unit square. The analysis and numerics indicate that this preconditioner significantly enhances the conditioning of the system, and that the overall scheme is efficient and effective for distributed parameter inverse problems.
On dynamical reconstruction of control in a system with time delay. Finite-dimensional models
Authors: Kappel F. , Maksimov V. I. , Skuratov E. N.
Published: September 2013

- The problem of dynamical reconstruction, of an unknown control acting upon a linear time-delay system, through inaccurate observations of phase states is discussed. A regularized solving algorithm functioning in real time mode is proposed. This algorithm is stable with respect to informational noise and computational errors.
On the problem of optimal compatibility
Authors: Kryazhimskii A. V. , Paschenko S.V.
Published: September 2013

- A method of finding solutions for the optimal compatibility problem in Hilbert spaces is suggested. The accuracy estimates for approximate solutions are presented and a constructive regularization algorithm for the ill-posed problem is described.
Optimal sensor allocation for parameter estimation in distributed systems
Authors: Uciński D. , Korbicz J.
Published: September 2013

- Some fundamental results of the modern theory of optimum experimental design are extended here to address the problem of determining the optimal measurement scheduling, encountered while estimating unknown parameters in mathematical models described by partial differential equations from observations of the underlying physical phenomenon being modelled. Special emphasis is put on measurements realized by optimal motion of spatially-movable sensors for which we generalize the approach advanced by Rafajłowicz in his seminal paper [16] to the case of minimizing a general performance index defined on the Fisher information matrix related to the parameters to be identified. Since only the measurability of the resulting trajectories can be guaranteed, we also show how to ease this inconvenience by introducing a suitable parametrization of the set of admissible solutions. In the latter case, we also detail how to adapt standard sequential numerical algorithms of optimum experimental design so that they could be employed for computation of trajectories in particular situations.
Theoretical analysis of inverse extremal problems of admixture diffusion in viscous fluids
Authors: Alekseev G.V. , Adomavichus E.A.
Published: September 2013

- We consider some inverse extremal problems for the stationary equations of admixture diffusion in a viscous incompressible fluid under inhomogeneous boundary conditions for the velocity and concentration. We prove theorems on existence of solutions for the considered inverse problems, derive and analyze the optimality systems, and also establish conditions of uniqueness of their solutions for concrete objective functionals. The conditions of solvability of inverse extremal problems for the stationary Navier - Stokes equations are presented.
Recovering the conductivity at the boundary from the Dirichlet to Neumann map: a pointwise result
Authors: Brown R. M.
Published: September 2013

- A formula is given for recovering the boundary values of the coefficient γ of an elliptic operator, divγ∇, from the Dirichlet to Neumann map. The main point is that one may recover γ without any a priori smoothness assumptions. The formula allows one to recover the value of γ pointwise.
The reconstruction of a vector field by finite difference methods
Authors: Bezuglova M. A. , Derevtsov E.Yu. , Sorokin S. B.
Published: September 2013

- The problem of reconstruction of a vector field, given in a refracting medium, is considered. The approach to an approximate solution of the problem consisting in combination of variational, geometrical and finite difference methods is implemented. A polynomial approximation of the vector field, obtained by method of least squares, can contain an arbitrary potential part. A determination of the potential part of a required approximation of the field therefore is necessary by a solution of a homogeneous boundary value problem for the equation of Beltrami- Laplace in a bounded domain with an arbitrary configuration of boundaries. The formulated boundary value problem is solved by finite difference methods with usage of a continuous isometry of an original domain with the given Riemannian metric on a domain with the reference configuration of a boundary. For such domain the effective finite difference and iterative methods designed, the necessary evaluations and numerical experiments are produced.
The linear sampling method in inverse obstacle scattering for impedance boundary conditions
Authors: Grinberg N. , Kirsch A.
Published: September 2013

- In this paper we study the inverse scattering problem to determine the shape of a scatterer from either far field data for plane wave incidence or near field data for point sources as incident fields. As the simplest case of an absorbing medium we consider an impedance boundary condition with complex valued impedance λ on the boundary of the obstacle. We extend a new approach which characterizes the domain by those points z ∈ℝ3 for which a certain function attains zero as its minimal value. This function is given as the cost functional of an optimization problem and depends explicitly on the data and the points z. An valuable feature of this approach is that it does not assume any a priori knowledge on the number of components of the obstacle or even the type of boundary condition. Some examples show the usefulness of this approach also from the numerical point of view.
On reconstruction of surfaces by shadow contours
Authors: Begmatov A. H.
Published: September 2013

- The problem of reconstruction of surfaces based on a given plane by their shadow contours is considered. The optical projection of the surface point and shadow contours with respect to perpendicular and optical projection is introduced. Necessary and sufficient conditions of unique reconstruction of a plane curve by complete set of optical and perpendicular projections of their points are presented. A uniqueness result on the problem is obtained in the case of smooth hat-shaped surface. A uniqueness theorem for the problem of simultaneous reconstruction of two nonintersecting piecewise-smooth hat-shaped surfaces by complete set of their shadows is proved.
Regularized data-driven construction of fuzzy controllers
Authors: Burger M. , Haslinger J. , Bodenhofer U. , Engl H. W.
Published: September 2013

- This paper is devoted to the mathematical analysis and the numerical solution of data-driven construction of fuzzy controllers. We show that for a special class of controllers (so-called Sugeno controllers), the design problem is equivalent to a nonlinear least squares problem, which turns out to be ill-posed. Therefore we investigate the use of regularization in order to obtain stable approximations of the solution. We analyze a smoothing method, which is common in spline approximation, as well as Tikhonov regularization with respect to stability and convergence.

In addition, we develop an iterative method for the regularized problems, which uses the special structure of the problem and test it in some typical numerical examples. We also compare the behavior of the iterations for the original and the regularized least squares problems. It turns out that the regularized problem is not only more robust but also favors solutions that are interpretable easily, which is an important criterion for fuzzy systems.
Some inverse problems for Schrödinger operator with Kato potential
Authors: Razborov A. G. , Sagyndykov M. K. , Serov V. S.
Published: September 2013

- We prove that in multidimensional potential scattering some familiar methods of reconstructing unknown potential are valid also for the potentials from the Kato space. We also show a new method for recovering such potentials. The proof is based on the new estimates for Schrödinger operator for the continuous spectrum. These estimates allow us for the cases n = 2 and n = 3 to consider the potentials with stronger singularities than in previous publications.
Inverse scattering by the stability index method
Authors: Gutman S. , Ramm A.G. , Scheid W.
Published: September 2013

- A novel numerical method for solving inverse scattering problem with fixed-energy data is proposed. The method contains a new important concept: the stability index of the inversion problem. This is a number, computed from the data, which shows how stable the inversion is. If this index is small, then the inversion provides a set of potentials which differ so little, that practically one can represent this set by one potential. If this index is larger than some threshold, then practically one concludes that with the given data the inversion is unstable and the potential cannot be identified uniquely from the data. Inversion of the fixed-energy phase shifts for several model potentials is considered. The results show practical efficiency of the proposed method. The method is of general nature and is applicable to a very wide variety of the inverse problems.
Determination of a right-hand side term in an operator-differential equation of mixed type
Authors: Abasheeva N. L.
Published: September 2013

- Existence and uniqueness of solution to the inverse problem But
+Lu = γ(t)ϕ+f(t), u(0) = u
0, u(T) = uT are investigated. Operators B and L are selfadjoint in a Hilbert space E; the spectrum of the operator L is semibounded; γ(t) is a scalar function. If a finite number of orthogonality conditions holds then the inverse problem is uniquely solvable. The method uses the representation as a series in eigenelements and associated elements of the pencil L − λB.
Iterative method for recovery a nonlinear source in a hyperbolic equation with final overdetermination
Authors: Shcheglov A.Yu.
Published: September 2013

- We consider here the inverse problem, which consists in recovery of a nonlinear source in the equation of hyperbolic type with constant coefficients in main part of differential operator. The additional information for solution of the inverse problem is given in the form of final overdetermination. The iterative algorithm for recovery of the source is based on the theorem of existence and uniqueness of solution for the inverse problem that is proved in small. The convergence of the iterative method for solving the inverse problem is established.
Fetal volume at 11–14 gestational weeks: reference ranges and association with first trimester biochemical and biophysical markers
Authors: Papastefanou Ioannis , Kappou Dimitra , Souka Athena P. , Chrelias Charalambos , Siristatidis Charalambos , Pilalis Athanasios , Kassanos Demetrios
Published: September 2013

Aims: To establish reference ranges for fetal volume (FV) measured by three-dimensional ultrasound (3D-US) at 11–14 weeks of gestation and to examine the possible association of FV with maternal/pregnancy characteristics and biochemical parameters.

Methods: Prospective observational study on 240 fetuses at 11–14 weeks. FV was measured by 3D-US using Virtual Organ Computer-Aided Analysis. Pearson correlation coefficient (cc) and regression analysis were used.

Results: FV increased exponentially with crown rump length and was unrelated to maternal weight (cc=–0.137, P=0.071), age (cc=0.009, P=0.899), parity (0.76), smoking status (t-test, P=0.149) and mode of conception (t-test, P=0.8). Z-scores (z) of FV was not associated with z-mean uterine artery pulsatility index (cc=–0.026, P=0.733), log10 multiples of the median (MoM) free beta human chorionic gonadotrophin (cc=0.002, P=0.982), delta value (d) of nuchal translucency (cc=0.072, P=0.331) and d-fetal heart rate (cc=0.009, P=0.902), z-FV was significantly positively correlated with log10 MoM pregnancy associated plasma protein-A (PAPP-A; regression coefficient=1.420976, R2=0.0957, P<0.0001).

Conclusions: FV is strongly related to PAPP-A even after adjustment for crown rump length with a mechanism unrelated to placental perfusion. FV is independent of the vast majority of first trimester parameters; hence, it is a promising marker of early fetal growth.
How did vocal behavior “take over” the gestural communication system?
Authors: Aboitiz Francisco
Published: September 2013

In this commentary, I argue (i) that there are some peripheral homologies between the monkey and the human vocalization systems; (ii) that complex vocal learning can be achieved without need of a voluntary hand grasping circuit; and (iii) that in the monkey there are rudimentary circuits that can convey auditory information into Broca's region, via the “ventral pathway” but also via the arcuate or the superior longitudinal fasciculi.
The tip of the language iceberg
Authors: Dominey Peter Ford
Published: September 2013

Arbib's How the brain got language is a major achievement in defining a trajectory for the evolution of complex imitation and the language-ready brain leading to human language. In addition to these capabilities, I will suggest that it is useful to consider two additional components of human brain function that are intricately related to the emergence of language. These are, first, the profound human motivation to represent and share the psychological states of others, and second, the related complex semantic system that represents the contents of what is communicated in language. In this sense, these two components represent part of what is under the iceberg, where language is the emerging tip.
Vive la différence: Sign language and spoken language in language evolution
Authors: Sandler Wendy
Published: September 2013

Michael Arbib's book proposes a scenario of language evolution that begins with pantomime, progresses to proto-sign, and then develops together with proto-speech in an “expanding spiral” to create a language-ready brain. The richness of detail in Arbib's hypothesis makes serious appraisal of each of its aspects possible. Here I describe findings about established and emerging sign languages that bear specifically upon the interaction between sign and speech proposed in the Mirror System Hypothesis. While supporting the central role that Arbib attributes to gestural/visual communication in understanding language and its evolution, I point out some kinks in the spiral that potentially disrupt its smooth expansion. One is the fact that each modality relies on an entirely different motor system. Another is the type of relation that holds between the articulators and grammatical structure, which is radically different in each system as well. A third kink disrupts the proposed continuity between holistic pantomime (gestural holophrases) and signs. Given such differences, instead of a scenario in which speech grew out of sign, it seems more likely that the two modalities complemented each other symbiotically throughout evolution as they do today. If so, then the modern ability to spontaneously create sign languages reveals the extraordinary richness and plasticity of human cognition, and not an evolutionary stepping stone to speech.
What happens to the motor theory of perception when the motor system is damaged?
Authors: Stasenko Alena , Garcea Frank E. , Mahon Bradford Z.
Published: September 2013

Motor theories of perception posit that motor information is necessary for successful recognition of actions. Perhaps the most well known of this class of proposals is the motor theory of speech perception, which argues that speech recognition is fundamentally a process of identifying the articulatory gestures (i.e. motor representations) that were used to produce the speech signal. Here we review neuropsychological evidence from patients with damage to the motor system, in the context of motor theories of perception applied to both manual actions and speech. Motor theories of perception predict that patients with motor impairments will have impairments for action recognition. Contrary to that prediction, the available neuropsychological evidence indicates that recognition can be spared despite profound impairments to production. These data falsify strong forms of the motor theory of perception, and frame new questions about the dynamical interactions that govern how information is exchanged between input and output systems.
Complex imitation and the language-ready brain
Authors: Arbib Michael A.
Published: September 2013

The present article responds to commentaries from experts in anthropology, apraxia, archeology, linguistics, neuroanatomy, neuroimaging, neurophysiology, neuropsychology, primatology, sign language emergence and sign language neurolinguistics on the bookHow the brain got language: The mirror system hypothesis(Arbib 2012). The role of complex imitation is discussed, and the distinction between protolanguage and language is emphasized. Issues debated include the role of protosign in scaffolding protospeech, the interplay between biological evolution of the brain and cultural evolution of the social interactions within groups, the relations brain mechanisms for action and language, and the question of when language first emerged.
Resolving the thermal challenges for silicon microring resonator devices
Authors: Padmaraju Kishore , Bergman Keren
Published: September 2013

Silicon microring resonators have been hailed for their potential use in next-generation optical interconnects. However, the functionality of silicon microring based devices suffer from susceptibility to thermal fluctuations that is often overlooked in their demonstrated results, but must be resolved for their future implementation in microelectronic applications. We survey the emerging efforts that have been put forth to resolve these thermal susceptibilities and provide a comprehensive discussion of their advantages and disadvantages.
Light manipulation principles in biological photonic systems
Authors: Starkey Tim , Vukusic Pete
Published: September 2013

The science of light and colour manipulation continues to generate interest across a range of disciplines, from mainstream biology, across multiple physics-based fields, to optical engineering. Furthermore, the study of light production and manipulation is of significant value to a variety of industrial processes and commercial products. Among the several key methods by which colour is produced in the biological world, this review sets out to describe, in some detail, the specifics of the method involving photonics in animal and plant systems; namely, the mechanism commonly referred to as structural colour generation. Not only has this theme been a very rapidly growing area of physics-based interest, but also it is increasingly clear that the biological world is filled with highly evolved structural designs by which light and colour strongly influence behaviours and ecological functions.
Dynamic Tuning of Electrical and Chemical Synaptic Transmission in a Network of Motion Coding Retinal Neurons
Authors: Trenholm Stuart , McLaughlin Amanda J. , Schwab David J. , Awatramani Gautam B.
Published: September 2013

Recently, we demonstrated that gap junction coupling in the population of superior coding ON-OFF directionally selective ganglion cells (DSGCs) genetically labeled in the Hb9::eGFP mouse retina allows the passage of lateral anticipatory signals that help track moving stimuli. Here, we examine the properties of gap junctions in the DSGC network, and address how interactions between electrical and chemical synapses and intrinsic membrane properties contribute to the dynamic tuning of lateral anticipatory signals. When DSGC subtypes coding all four cardinal directions were individually loaded with the gap junction-permeable tracer Neurobiotin, only superior coding DSGCs exhibited homologous coupling. Consistent with these anatomical findings, gap junction-dependent feedback spikelets were only observed in Hb9+DSGCs. Recordings from pairs of neighboring Hb9+DSGCs revealed that coupling was reciprocal, non-inactivating, and relatively weak, and provided a substrate for an extensive subthreshold excitatory receptive field around each cell. This subthreshold activity appeared to boost coincident light-driven chemical synaptic responses. However, during responses to moving stimuli, gap junction-mediated boosting appeared to be dynamically modulated such that upstream DSGCs primed downstream cells, but not vice versa, giving rise to highly skewed responses in individual cells. We show that the asymmetry in priming arises from a combination of spatially offset GABAergic inhibition and activity-dependent changes in intrinsic membrane properties of DSGCs. Thus, dynamic interactions between electrical and chemical synapses and intrinsic membrane properties allow the network of DSGCs to propagate anticipatory responses most effectively along their preferred direction without leading to runaway excitation.
Interacting Linear and Nonlinear Characteristics Produce Population Coding Asymmetries between ON and OFF Cells in the Retina
Authors: Nichols Zachary , Nirenberg Sheila , Victor Jonathan
Published: September 2013

The early visual system is a model for understanding the roles of cell populations in parallel processing. Cells in this system can be classified according to their responsiveness to different stimuli; a prominent example is the division between cells that respond to stimuli of opposite contrasts (ON vs OFF cells). These two cell classes display many asymmetries in their physiological characteristics (including temporal characteristics, spatial characteristics, and nonlinear characteristics) that, individually, are known to have important roles in population coding. Here we describe a novel distinction between the information that ON and OFF ganglion cell populations carry in mouse—that OFF cells are able to signal motion information about both light and dark objects, while ON cells have a selective deficit at signaling the motion of dark objects. We found that none of the previously reported asymmetries in physiological characteristics could account for this distinction. We therefore analyzed its basis via a recently developed linear–nonlinear-Poisson model that faithfully captures input/output relationships for a broad range of stimuli (Bomash et al., 2013). While the coding differences between ON and OFF cell populations could not be ascribed to the linear or nonlinear components of the model individually, they had a simple explanation in the way that these components interact. Sensory transformations in other systems can likewise be described by these models, and thus our findings suggest that similar interactions between component properties may help account for the roles of cell classes in population coding more generally.
Rapid Recalibration to Audiovisual Asynchrony
Authors: Van der Burg Erik , Alais David , Cass John
Published: September 2013

To combine information from different sensory modalities, the brain must deal with considerable temporal uncertainty. In natural environments, an external event may produce simultaneous auditory and visual signals yet they will invariably activate the brain asynchronously due to different propagation speeds for light and sound, and different neural response latencies once the signals reach the receptors. One strategy the brain uses to deal with audiovisual timing variation is to adapt to a prevailing asynchrony to help realign the signals. Here, using psychophysical methods in human subjects, we investigate audiovisual recalibration and show that it takes place extremely rapidly without explicit periods of adaptation. Our results demonstrate that exposure to a single, brief asynchrony is sufficient to produce strong recalibration effects. Recalibration occurs regardless of whether the preceding trial was perceived as synchronous, and regardless of whether a response was required. We propose that this rapid recalibration is a fast-acting sensory effect, rather than a higher-level cognitive process. An account in terms of response bias is unlikely due to a strong asymmetry whereby stimuli with vision leading produce bigger recalibrations than audition leading. A fast-acting recalibration mechanism provides a means for overcoming inevitable audiovisual timing variation and serves to rapidly realign signals at onset to maximize the perceptual benefits of audiovisual integration.
P-Selectin-Mediated Monocyte–Cerebral Endothelium Adhesive Interactions Link Peripheral Organ Inflammation To Sickness Behaviors
Authors: D'Mello Charlotte , Riazi Kiarash , Le Tai , Stevens Katarzyna M. , Wang Arthur , McKay Derek M. , Pittman Quentin J. , Swain Mark G.
Published: September 2013

Sickness behaviors, such as fatigue, mood alterations, and cognitive dysfunction, which result from changes in central neurotransmission, are prevalent in systemic inflammatory diseases and greatly impact patient quality of life. Although, microglia (resident cerebral immune cells) and cytokines (e.g., TNFα) are associated with changes in central neurotransmission, the link between peripheral organ inflammation, circulating cytokine signaling, and microglial activation remains poorly understood. Here we demonstrate, using cerebral intravital microscopy, that in response to liver inflammation, there is increased monocyte specific rolling and adhesion along cerebral endothelial cells (CECs). Peripheral TNFα-TNFR1 signaling and the adhesion molecule P-selectin are central mediators of these monocyte–CEC adhesive interactions which were found to be closely associated with microglial activation, decreased central neural excitability and sickness behavior development. Similar monocyte-CEC adhesive interactions were also observed in another mouse model of peripheral organ inflammation (i.e., 2,4-dinitrobenzene sulfonic acid-induced colitis). Our observations provide a clear link between peripheral organ inflammation and cerebral changes that impact behavior, which can potentially allow for novel therapeutic interventions in patients with systemic inflammatory diseases.
The Pattern of Cortical Dysfunction in a Mouse Model of a Schizophrenia-Related Microdeletion
Authors: Fénelon Karine , Xu Bin , Lai Cora S. , Mukai Jun , Markx Sander , Stark Kimberly L. , Hsu Pei-Ken , Gan Wen-Biao , Fischbach Gerald D. , MacDermott Amy B. , Karayiorgou Maria , Gogos Joseph A.
Published: September 2013

We used a mouse model of the schizophrenia-predisposing 22q11.2 microdeletion to evaluate how this genetic lesion affects cortical neural circuits at the synaptic, cellular, and molecular levels. Guided by cognitive deficits, we demonstrated that mutant mice display robust deficits in high-frequency synaptic transmission and short-term plasticity (synaptic depression and potentiation), as well as alterations in long-term plasticity and dendritic spine stability. Apart from previously reported reduction in dendritic complexity of layer 5 pyramidal neurons, altered synaptic plasticity occurs in the context of relatively circumscribed and often subtle cytoarchitectural changes in neuronal density and inhibitory neuron numbers. We confirmed the pronounced DiGeorge critical region 8 (Dgcr8)-dependent deficits in primary micro-RNA processing and identified additional changes in gene expression and RNA splicing that may underlie the effects of this mutation. Reduction inDgcr8levels appears to be a major driver of altered short-term synaptic plasticity in prefrontal cortex and working memory but not of long-term plasticity and cytoarchitecture. Our findings inform the cortical synaptic and neuronal mechanisms of working memory impairment in the context of psychiatric disorders. They also provide insight into the link between micro-RNA dysregulation and genetic liability to schizophrenia and cognitive dysfunction.
Lhx3-Chx10 Reticulospinal Neurons in Locomotor Circuits
Authors: Bretzner Frédéric , Brownstone Robert M.
Published: September 2013

Motor behaviors result from the interplay between the brain and the spinal cord. Reticulospinal neurons, situated between the supraspinal structures that initiate motor movements and the spinal cord that executes them, play key integrative roles in these behaviors. However, the molecular identities of mammalian reticular formation neurons that mediate motor behaviors have not yet been determined, thus limiting their study in health and disease. In the medullary reticular formation of the mouse, we identified neurons that express the transcription factors Lhx3 and/or Chx10, and demonstrate that these neurons form a significant component of glutamatergic reticulospinal pathways. Lhx3-positive medullary reticular formation neurons express Fos following a locomotor task in the adult, indicating that they are active during walking. Furthermore, they receive functional inputs from the mesencephalic locomotor region and have electrophysiological properties to support tonic repetitive firing, both of which are necessary for neurons that mediate the descending command for locomotion. Together, these results suggest that Lhx3/Chx10 medullary reticular formation neurons are involved in locomotion.
Dynein-Dependent Transport ofnanosRNA inDrosophilaSensory Neurons Requires Rumpelstiltskin and the Germ Plasm Organizer Oskar
Authors: Xu Xin , Brechbiel Jillian L. , Gavis Elizabeth R.
Published: September 2013

Intracellular mRNA localization is a conserved mechanism for spatially regulating protein production in polarized cells, such as neurons. The mRNA encoding the translational repressor Nanos (Nos) forms ribonucleoprotein (RNP) particles that are dendritically localized inDrosophilalarval class IV dendritic arborization (da) neurons. Innosmutants, class IV da neurons exhibit reduced dendritic branching complexity, which is rescued by transgenic expression of wild-typenosmRNA but not by a localization-compromisednosderivative. While localization is essential fornosfunction in dendrite morphogenesis, the mechanism underlying the transport ofnosRNP particles was unknown. We investigated the mechanism of dendriticnosmRNA localization by analyzing requirements fornosRNP particle motility in class IV da neuron dendrites through live imaging of fluorescently labelednosmRNA. We show that dynein motor machinery components mediate transport ofnosmRNA in proximal dendrites. Two factors, the RNA-binding protein Rumpelstiltskin and the germ plasm protein Oskar, which are required for diffusion/entrapment-mediated localization ofnosduring oogenesis, also function in da neurons for formation and transport ofnosRNP particles. Additionally, we show thatnosregulates neuronal function, most likely independent of its dendritic localization and function in morphogenesis. Our results reveal adaptability of localization factors for regulation of a target transcript in different cellular contexts.
A Road Trip Along the Aqueduct in 1915
Authors: Powers Annie
Published: September 2013

A partially reproduced photo album of two men, William Oliver and Henry Frick, who photographed their road trip along the Los Angeles aqueduct in 1915. The photos and their captions reveal contemporary car culture, engagement with the film industry, and interest in the origins of water in LA.
A DNA Sequence Element That Advances Replication Origin Activation Time in Saccharomyces cerevisiae
Authors: Pohl Thomas J , Kolor Katherine , Fangman Walton L , Brewer Bonita J , Raghuraman M K
Published: September 2013

Eukaryotic origins of DNA replication undergo activation at various times in S-phase, allowing the genome to be duplicated in a temporally staggered fashion. In the budding yeast Saccharomyces cerevisiae, the activation times of individual origins are not intrinsic to those origins but are instead governed by surrounding sequences. Currently, there are two examples of DNA sequences that are known to advance origin activation time, centromeres and forkhead transcription factor binding sites. By combining deletion and linker scanning mutational analysis with two-dimensional gel electrophoresis to measure fork direction in the context of a two-origin plasmid, we have identified and characterized a 19- to 23-bp and a larger 584-bp DNA sequence that are capable of advancing origin activation time.
János Kornai’s Anti-Equilibrium, a harbinger of evolutionary economics
Authors: Mihalyi Peter
Published: September 2013

Anti-Equilibrium (1971) was well ahead of its time in emphasising that (i) economics should draw from biology, rather than physics, as its methodological underpinning; (ii) evolutionary logic requires a different type of decision-making in simple, routine matters, as opposed to large and important decisions; (iii) the most important production processes are non-linear, with increasing returns to scale being the rule, rather than the exception in modern capitalist economies and — in conclusion — that there is no such thing as general equilibrium. In modern societies, goods and services are either in shortage (Socialism) or in a state of oversupply (Capitalism). It is either a buyers’ market or sellers’ market.
Processing influence on the reliability of platinum thin films for MEMS applications
Authors: Briand Danick , Heimgartner Stephan , Leboeuf Mireille , Dadras Massoud , Rooij Nico F. de
Published: September 2013

The influence of high temperature post-processes on the microstructural, electrical, and mechanical properties of evaporated platinum thin films with tantalum as adhesion layer was investigated. Post-processes, such as deposition of a silicon nitride passivation layer by LPCVD and annealing at high temperature (up to 830°C) in an inert or reactive gaseous atmosphere, were performed separately or successively on platinum/tantalum films having different thickness. An abnormal grain growth and a grain reorientation occurred in the platinum films during the heat treatments, with more severe hillocks formation when performed in air at temperatures higher than 500°C. Another parameter influencing the electrical characteristics (resistivity, temperature coefficient of resistance) of these films, in addition to the post-processing temperature and time, was the thickness of the platinum film.

A passivation made of LPCVD silicon nitride film was shown to stabilise the electrical properties of the Pt/Ta films before post-processing or operating them at high temperatures, up to the deposition temperature of the passivation film. However, if the passivation is removed, postprocessing of the Pt films at a higher temperature than 500°C in air induced more or less severe hillocks formation and adhesion problems could occur, related to the oxidation of tantalum. The adhesion of the Pt/Ta films was found to depend on the thickness of the LPCVD silicon nitride film deposited, which was removed before annealing in air. The Pt/Ta films properties depend on the annealing conditions, time and temperature, and on the history of the film, if the annealing was performed just after its deposition or after successive thermal processes.
Evaluation of thyroid function and autoimmunity in HIV-infected women
Authors: Carvalho Leiliane Gonçalves de , Teixeira Patrícia de Fátima dos Santos , Panico Ana Luiza Brandão Galotti , Cohen Marcela Vaisberg , Pinheiro Maria Fernanda Miguens Castelar , Barroso Paulo Feijó , Vaisman Mário
Published: September 2013

Autoimmune thyroid diseases (AITD) are the main causes of thyroid dysfunction and the most common autoimmune diseases in the world. An association between AITD and infections with the human immunodeficiency virus (HIV), in combination with the effects of highly active anti-retroviral therapy (HAART), has been suggested by several research groups. The aim of the present study was to evaluate the frequency of thyroid dysfunction and AITD in women > 35 years of age infected with HIV, and to identify factors associated with the emergence of these thyroid abnormalities. HIV-infected women (n = 153) selected from the infectious disease outpatient clinic at a University Hospital in Rio de Janeiro were characterized based on their circulating CD4+ lymphocytes levels, viral loads, serum TSH levels, and the presence of FT4 and anti-thyroperoxidase antibodies (TPO-Ab). A total of 129 participants were on HAART and 24 were not. The frequency of thyroid disorders was 7.8% (12/153 patients) and all were on HAART at the time of diagnosis, yielding a prevalence of 9.3% in patients receiving HAART compared with 0% in patients not on HAART. AITD, hyper, and hypothyroidism were detected in 4.6%, 3.1%, and 4.1% of HAART patients. It was not detected any thyroid dysfunction or autoimmunity in HIV-infected women not on HAART. This study demonstrated an association between HAART and the development of AITD. In addition AITD only developed in HAART patients also presenting with undetectable viral loads and slightly elevated CD4+ T cell counts.
Associação entre consumo de alimentos embutidos e obesidade em um estudo de base populacional de nipo-brasileiros
Authors: Cristofoletti Maria F. , Gimeno Suely G. A. , Ferreira Sandra R. G. , Cardoso Marly A.
Published: September 2013

OBJETIVO: Investigar a associação entre consumo de alimentos embutidos e obesidade generalizada, abdominal e generalizada com abdominal em nipo-brasileiros de Bauru, SP. SUJEITOS E MÉTODOS: Quatrocentos e quarenta e três mulheres e 329 homens nipo-brasileiros não miscigenados (≥ 30 anos) foram avaliados em estudo transversal de base populacional. Para o diagnóstico de obesidade, foram empregados os critérios da Organização Mundial da Saúde para asiáticos. A ingestão de alimentos foi avaliada por meio de questionário de frequência alimentar validado. A ingestão foi estratificada em terços para análise. RESULTADOS: Nos homens, a ingestão de colesterol e alimentos embutidos mostrou-se positivamente associada à obesidade generalizada com abdominal quando o primeiro terço de ingestão foi comparado ao último, após ajustes (OR 2,97; IC95% 1,13-7,78). Em mulheres, somente o grupo das carnes vermelhas associou-se à obesidade geral com abdominal após ajustes (OR 0,47; IC95% 0,23-0,96). CONCLUSÃO: Ingestão elevada de alimentos embutidos associou-se à obesidade generalizada com adiposidade abdominal em homens nipo-brasileiros, mas não em mulheres.
Horner syndrome as a manifestation of thyroid carcinoma: a rare association
Authors: Pereira Bernardo , Silva Tiago , Luiz Henrique , Manita Isabel , Raimundo Luísa , Portugal Jorge
Published: September 2013

An 82-year-old patient presented a progressively growing hard thyroid nodule, and left ptosis. Additionally, ophthalmologic evaluation revealed ipsilateral miosis, diagnostic findings of Horner syndrome. Computerized tomography revealed a 7.5-cm thyroid mass infiltrating the main neck vessels. Although clinical and imaging data were suggestive of poorly differentiated thyroid carcinoma, fine-needle aspiration led to the diagnosis of papillary carcinoma. Paliative care was proposed to the patient due to the advanced stage of the neoplasm and to significant comorbidities. Horner syndrome is an infrequent manifestation of thyroid disorders and benign etiologies are more often implied. Malignant thyroid neoplasms represent a rare cause of Horner syndrome. However, an appropriate and prompt diagnosis is paramount for timely treatment of rare thyroid malignancies.
Vivendo o risco de enchentes: relatos de moradores de Campo Grande/MS
Authors: Vasconcelos Dalila Castelliano de , Coêlho Angela Elizabeth Lapa
Published: September 2013

As enchentes vêm desabrigando e causando a morte de famílias no Brasil. O objetivo desta pesquisa foi identificar as vivências de pessoas que moraram durante muitos anos em uma área de risco, à beira de um córrego em Campo Grande-MS. Este estudo é inovador por abordar tal vivência como um fenômeno psicossocial. Foram realizadas entrevistas estruturadas com 19 idosos, discutidas a partir da análise de conteúdo. Para os moradores, o principal problema relativo à habitação eram as enchentes, por si só, sem atrelá-las a uma conjuntura mais ampla de risco ambiental. Por isso, perceber tal localidade como área de risco era de difícil compreensão. Faz-se necessário realizar estudos que contemplem a relação pessoa-ambiente, em uma perspectiva psicossocial, considerando que as pessoas utilizam aspectos subjetivos para compreensão de risco. Processos que envolvam essa perspectiva poderão colaborar na promoção da saúde aliada a conscientização ambiental.