Higher-order Forms Research Articles

Role of the basolateral amygdala and NMDA receptors in higher-order conditioned fear

Laboratory rats learn to fear relatively innocuous stimuli which signal the imminent arrival of an innate source of danger, typically brief but aversive foot shock. Much is now known about the neural substrates underlying the acquisition, consolidation and subsequent expression of this fear. Rats also learn to fear stimuli which signal learned sources of danger but relatively little is known about the neural substrates underlying this form of fear. Two Pavlovian conditioning paradigms used to study this form of fear are second-order conditioning and sensory preconditioning. In second-order conditioning, rats are first exposed to a signaling relationship between one stimulus, such as a tone, and aversive foot shock, and then to a signaling relationship between a second stimulus, such as a light, and the now dangerous tone. In sensory preconditioning, these phases are reversed: rats are first exposed to a signaling relationship between the light and the tone and then to a signaling relationship between the tone and the foot shock. In both paradigms, rats exhibit fear when tested with the light. In this review paper, we describe the evidence for higher-order forms of conditioning, the conditions which promote this learning and its contents. We compare and contrast the substrates of the learning underlying second-order and sensory preconditioning fear with those known to underlie the better studied first-order conditioned fear. We conclude with some comments as to the role of higher-order processes in anxiety disorders.

Targeting chemokine receptors in allergic disease

The directed migration of cells in response to chemical cues is known as chemoattraction, and plays a key role in the temporal and spatial positioning of cells in lower- and higher-order life forms. Key molecules in this process are the chemotactic cytokines, or chemokines, which, in humans, constitute a family of approx. 40 molecules. Chemokines exert their effects by binding to specific GPCRs (G-protein-coupled receptors) which are present on a wide variety of mature cells and their progenitors, notably leucocytes. The inappropriate or excessive generation of chemokines is a key component of the inflammatory response observed in several clinically important diseases, notably allergic diseases such as asthma. Consequently, much time and effort has been directed towards understanding which chemokine receptors and ligands are important in the allergic response with a view to therapeutic intervention. Such strategies can take several forms, although, as the superfamily of GPCRs has historically proved amenable to blockade by small molecules, the development of specific antagonists has been has been a major focus of several groups. In the present review, I detail the roles of chemokines and their receptors in allergic disease and also highlight current progress in the development of relevant chemokine receptor antagonists.

Visual Cognition in Social Insects

Visual learning admits different levels of complexity, from the formation of a simple associative link between a visual stimulus and its outcome, to more sophisticated performances, such as object categorization or rules learning, that allow flexible responses beyond simple forms of learning. Not surprisingly, higher-order forms of visual learning have been studied primarily in vertebrates with larger brains, while simple visual learning has been the focus in animals with small brains such as insects. This dichotomy has recently changed as studies on visual learning in social insects have shown that these animals can master extremely sophisticated tasks. Here we review a spectrum of visual learning forms in social insects, from color and pattern learning, visual attention, and top-down image recognition, to interindividual recognition, conditional discrimination, category learning, and rule extraction. We analyze the necessity and sufficiency of simple associations to account for complex visual learning in Hymenoptera and discuss possible neural mechanisms underlying these visual performances.

Lewis–Zagier correspondence for higher-order forms

The Lewis-Zagier correspondence attaches period functions to Maass wave forms. We extend this correspondence to wave forms of higher order, which are higher-order invariants of the Fuchsian group in question. The key ingredient, an identification of higher-order invariants with ordinary invariants of unipotent twists, makes it possible to apply standard methods of automorphic forms to higher-order forms.

Enthalpy predictive functional control of a pasteurisation plant based on a plate heat exchanger

Model predictive control (MPC) has been proven its efficiency in several industrial applications for over three decades. In this paper, predictive functional control (PFC) in its first order as well as its higher order forms is applied to control the pasteurisation temperature in a plate heat exchanger. The originality of the paper lies in the investigation of four control approaches using a combination of manipulated variables (medium temperature and product flow) tested in the presence of input disturbances and setpoint changes, leading to the so called 'enthalpy gearbox'. The paper describes the broad lines of first principles modelling of the studied pasteurisation plant sections, as well as giving an idea of the model accuracy when compared to real plant behaviour. A reminder of the first order PFC formulation as well as the full derivation of the analytical higher PFC control laws and the adequacy of a given control law over another are given. The PFC enthalpy approach (enthalpy gearbox) is finally compared in terms of performances to the simple PFC control scheme as well as the revisited performances given by classical control (PID) in terms of mean absolute error (MAE), overshooting and constraints violation.

Adaptive control design for uncertain polynomial nonlinear systems with parametric uncertainties

In this paper, we will develop an adaptive ℋ︁∞ control approach for a class of polynomial nonlinear systems with parametric uncertainties. Motivated by the dissipation theory and the vector projection technique, we propose a nonlinear adaptive ℋ︁∞ controller and its associated parameter adaptation law. The proposed adaptive control strategy is capable of identifying unknown parameter values quickly and minimizing the effect of estimation error. To further improve adaptive controlled performance, the Lyapunov function will be relaxed from quadratic to higher-order forms and the controller gains are generalized from constant to parameter-dependent. All of the synthesis conditions are formulated in the framework of polynomial/constant linear matrix inequalities and solvable using available software packages. Copyright © 2010 John Wiley & Sons, Ltd.

The development of luminance- and texture-defined form perception during the school-aged years

The objective of the present study was to assess the development of luminance- and texture-defined static form perception in school-aged children. This was done using an adapted Landolt-C technique where C-optotypes were defined by either luminance or texture information, the latter necessitating extra-striate neural processing to be perceived. Typically developing children were placed in one of 4 school-age groups (6, 8, 10 and 12-year olds); an adult group was also assessed. The contrast threshold for the correct identification of gap-opening-orientation for C-optotypes defined by either texture- or luminance-contrast was measured. All participants were presented with C-optotypes with gap-openings presented in one of 4 orientations (up, down, left or right). An adaptive staircase procedure was used to measure gap-opening-identification thresholds (minimum luminance- or texture-contrast modulation) for all three conditions and ages. As expected, gap-opening identification sensitivity (1/threshold) increased with age for all conditions. For both luminance-defined conditions, adult-like performance was manifested by 12 years of age. By comparison, at 12 years of age, the sensitivity to texture-defined C-optotypes was significantly lower than that of adults, having increased steadily from the age of 6 years. These results suggest that mechanisms underlying static form perception mature at different ages depending on the physical attribute defining the form. Luminance-defined form perception appears to reach adult-like levels (or plateau) earlier than for texture-defined information, suggesting that the development of mechanisms mediating higher-order form perception persist into adolescence.

Automated Reasoning in Higher-Order Logic using the TPTP THF Infrastructure

The Thousands of Problems for Theorem Provers (TPTP) problem library is the basis of a well known and well established infrastructure that supports research, development, and deployment of Automated Theorem Proving (ATP) systems. The extension of the TPTP from first-order form (FOF) logic to typed higher-order form (THF) logic has provided a basis for new development and application of ATP systems for higher-order logic. Key developments have been the specification of the THF language, the addition of higher-order problems to the TPTP, the development of the TPTP THF infrastructure, several ATP systems for higher-order logic, and the use of higher-order ATP in a range of domains. This paper describes these developments.

Effects of a genome-wide supported psychosis risk variant on neural activation during a theory-of-mind task

Schizophrenia is associated with marked deficits in theory of mind (ToM), a higher-order form of social cognition representing the thoughts, emotions and intentions of others. Altered brain activation in the medial prefrontal cortex and temporo-parietal cortex during ToM tasks has been found in patients with schizophrenia, but the relevance of these neuroimaging findings for the heritable risk for schizophrenia is unclear. We tested the hypothesis that activation of the ToM network is altered in healthy risk allele carriers of the single-nucleotide polymorphism rs1344706 in the gene ZNF804A, a recently discovered risk variant for psychosis with genome-wide support. In all, 109 healthy volunteers of both sexes in Hardy-Weinberg equilibrium for rs1344706 were investigated with functional magnetic resonance imaging during a ToM task. As hypothesised, risk carriers exhibited a significant (P<0.05 false discovery rate, corrected for multiple comparisons) risk allele dose effect on neural activity in the medial prefrontal cortex and left temporo-parietal cortex. Moreover, the same effect was found in the left inferior parietal cortex and left inferior frontal cortex, which are part of the human analogue of the mirror neuron system. In addition, in an exploratory analysis (P<0.001 uncorrected), we found evidence for aberrant functional connectivity between the frontal and temporo-parietal regions in risk allele carriers. To conclude, we show that a dysfunction of the ToM network is associated with a genome-wide supported genetic risk variant for schizophrenia and has promise as an intermediate phenotype that can be mined for the development of biological interventions targeted to social dysfunction in psychiatry.

Macrospin limit and configurational anisotropy in nanoscale permalloy triangles

In permalloy submicron triangles, configurational anisotropy—a higher-order form of shape anisotropy—yields three equivalent easy axes, imposed by the structures’ symmetry order. Supported by micromagnetic simulations, an experimental method was devised to evaluate the nanostructure dimensions for which a Stoner–Wohlfarth type of reversal could be used to describe this particular magnetic anisotropy. In this regime, a straightforward procedure using an in-plane rotating field allowed us to quantify experimentally the six-fold anisotropy fields for triangles of different thicknesses and sizes.

A new multiple Dirichlet series induced by a higher-order form

A multiple Dirichlet series in two variables is constructed as a Mellin transform of a higher order Eisenstein series. It is shown to extend to a meromorphic function and satisfy two independent functional equations.

Perceptual learning

Perceptual learning

A Sociopsychological Perspective on Collective Intelligence in Metaheuristic Computing

In studies of genetic algorithms, evolutionary computing, and ant colony mechanisms, it is recognized that the higher-order forms of collective intelligence play an important role in metaheuristic computing and computational intelligence. Collective intelligence is an integration of collective behaviors of individuals in social groups or collective functions of components in computational intelligent systems. This paper presents the properties of collective intelligence and their applications in metaheuristic computing. A social psychological perspective on collected intelligence is elaborated toward the studies on the structure, organization, operation, and development of collective intelligence. The collective behaviors underpinning collective intelligence in groups and societies are analyzed via the fundamental phenomenon of the basic human needs. A key question on how collective intelligence is constrained by social environment and group settings is explained by a formal motivation/attitude-driven behavioral model. Then, a metaheuristic computational model for a generic cognitive process of human problem solving is developed. This work helps to explain the cognitive and collective intelligent foundations of metaheuristic computing and its engineering applications.

Adaptability in organisms and artifacts: A multi level perspective on adaptive processes

Adaptability to changing circumstances is a key feature of living creatures. Understanding such adaptive processes is central to developing successful autonomous artifacts. In this paper two perspectives are brought to bear on the issue of adaptability. The first is a short term perspective which looks at adaptability in terms of the interactions between the agent and the environment. The second perspective involves a hierarchical evolutionary model which seeks to identify higher-order forms of adaptability based on the concept of adaptive meta-constructs. Task orientated and agent-centered models of adaptive processes in artifacts are considered from these two perspectives. The former is represented by the fitness function approach found in evolutionary learning, and the latter in terms of the concepts of empowerment and homeokinesis found in models derived from the self-organizing systems approach. A meta-construct approach to adaptability based on the identification of higher level meta-metrics is also outlined.

Higher-order threshold resummation for semi-inclusive [formula omitted] annihilation

The complete soft-enhanced and virtual-gluon contributions are derived for the quark coefficient functions in semi-inclusive e+e− annihilation to the third order in massless perturbative QCD. These terms enable us to extend the soft-gluon resummation for the fragmentation functions by two orders to the next-to-next-to-next-to-leading logarithmic (N3LL) accuracy. The resummation exponent is found to be the same as for the structure functions in inclusive deep-inelastic scattering. This finding, together with known results on the higher-order quark form factor, facilitates the determination of all soft and virtual contributions of the fourth-order difference of the coefficient functions for these two processes. Unlike the previous (N2LL) order in the exponentiation, the numerical effect of the N3LL contributions turns out to be negligible at LEP energies.

Evidence for heteromorphic chromatin fibers from analysis of nucleosome interactions

The architecture of the chromatin fiber, which determines DNA accessibility for transcription and other template-directed biological processes, remains unknown. Here we investigate the internal organization of the 30-nm chromatin fiber, combining Monte Carlo simulations of nucleosome chain folding with EM-assisted nucleosome interaction capture (EMANIC). We show that at physiological concentrations of monovalent ions, linker histones lead to a tight 2-start zigzag dominated by interactions between alternate nucleosomes (i +/- 2) and sealed by histone N-tails. Divalent ions further compact the fiber by promoting bending in some linker DNAs and hence raising sequential nucleosome interactions (i +/- 1). Remarkably, both straight and bent linker DNA conformations are retained in the fully compact chromatin fiber as inferred from both EMANIC and modeling. This conformational variability is energetically favorable as it helps accommodate DNA crossings within the fiber axis. Our results thus show that the 2-start zigzag topology and the type of linker DNA bending that defines solenoid models may be simultaneously present in a structurally heteromorphic chromatin fiber with uniform 30 nm diameter. Our data also suggest that dynamic linker DNA bending by linker histones and divalent cations in vivo may mediate the transition between tight nucleosome packing within discrete 30-nm fibers and self-associated higher-order chromosomal forms.

Tensor Decompositions and Applications

This survey provides an overview of higher-order tensor decompositions, their applications, and available software. A tensor is a multidimensional or N-way array. Decompositions of higher-order tensors (i.e., N-way arrays with $N \geq 3$) have applications in psycho-metrics, chemometrics, signal processing, numerical linear algebra, computer vision, numerical analysis, data mining, neuroscience, graph analysis, and elsewhere. Two particular tensor decompositions can be considered to be higher-order extensions of the matrix singular value decomposition: CANDECOMP/PARAFAC (CP) decomposes a tensor as a sum of rank-one tensors, and the Tucker decomposition is a higher-order form of principal component analysis. There are many other tensor decompositions, including INDSCAL, PARAFAC2, CANDELINC, DEDICOM, and PARATUCK2 as well as nonnegative variants of all of the above. The N-way Toolbox, Tensor Toolbox, and Multilinear Engine are examples of software packages for working with tensors.

Selective regulation of cellular and secreted multimeric adiponectin by antidiabetic therapies in humans

Adiponectin, an insulin-sensitizing factor secreted from adipose tissue, is decreased in individuals with type 2 diabetes (T2D) and increased in response to thiazolidinedione (TZD) therapy. Changes in its secretion and assembly into higher-order forms affect insulin sensitivity. To determine the relative potency of TZDs on intra-adipocyte multimerization and secretion of adiponectin, we assessed the impact of in vivo low- or high-dose rosiglitazone treatment alone or combined with metformin in subjects with T2D. T2D subjects received high-dose rosiglitazone (8 mg/day), high-dose metformin (2,000 mg/day), or low-dose combination rosiglitazone-metformin therapy (4 mg + 1,000 mg/day) for 4 mo. All subjects were then switched to high-dose rosiglitazone-metformin combination therapy (8 mg + 2,000 mg/day) for another 4 mo. Low-dose rosiglitazone increased serum adiponectin, whereas the high dose increased both adipocyte content and serum adiponectin levels. TZDs selectively increased the percentage of circulating adiponectin in the potent, high-molecular-weight (HMW) form. No TZD effects were evident on multimer distribution in the cell. Expression of the chaperone protein ERp44, which retains adiponectin within the cell, was decreased by TZD treatment. No changes occurred in Ero1-Lalpha expression. Metformin had no effect on any of these measures. Increases in adiponectin correlated with improvements in insulin sensitivity. In vivo, TZDs have apparent dose-dependent effects on cellular and secreted adiponectin. TZD-mediated improvements in whole body insulin sensitivity are associated with increases in circulating but not cellular levels of the HMW adiponectin multimer. Finally, TZDs promote the selective secretion of HMW adiponectin, potentially, in part, through decreasing the expression of the adiponectin-retaining protein ERp44.

Small-angle neutron scattering study of the vortex lattice in superconductingLuNi2B2C

We present studies of the magnetic field distribution around the vortices in ${\text{LuNi}}_{2}{\text{B}}_{2}\text{C}$. Small-angle neutron scattering measurements of the vortex lattice (VL) in this material were extended to unprecedentedly large values of the scattering vector $q$, obtained both by using high magnetic fields to decrease the VL spacing and by using higher order reflections. A square VL, oriented with the nearest-neighbor direction along the crystalline [110] direction, was observed up to the highest measured field. The first-order VL form factor, $|F({q}_{10})|$, was found to decrease exponentially with increasing magnetic field. Measurements of the higher-order form factors, $|F({q}_{hk})|$, reveal a significant in-plane anisotropy and also allow for a real-space reconstruction of the VL field distribution.

Automorphic forms of higher order

In this paper a theory of Hecke operators for higher-order modular forms is established. The definition of higher-order forms is extended beyond the realm of parabolic invariants. A canonical inner product is introduced. The role of representation theoretic methods is clarified and, motivated by higher-order forms, new convolution products of L-functions are introduced.