Pigeon basal ganglia: insights into the neuroanatomy underlying telencephalic sensorimotor processes in birds

This paper reviews the organization of the avian and mammalian striatum. The striatum receives input from virtually the entire rostrocaudal and mediolateral expanse of the cerebral cortex. The corticostriatal projections appear to be glutamatergic, forming excitatory synapses in the striatum. Another major projection to the avian striatum that also appears to be glutamatergic stems from a set of nuclei in the dorsal zone of the avian thalamus that are comparable to the mammalian intralaminar, mediodorsal, and midline nuclei. Furthermore, the striatum receives a massive projection from dopaminergic neurons of the ventral tegmental area and substantia nigra in the midbrain tegmentum. In return, the midbrain tegmentum receives a direct GABAergic/substance P-ergic/ dynorphinergic projection from the striatum, as well as an indirect one formed by GABAergic/substance P-ergic/ dynorphinergic and GABA-ergic/enkephalinergic striatal neurons projecting to the pallidum in the first step, and pallidal GABAergic/LANT6/parvalbumin neurons projecting to the midbrain tegmentum in the second step. In addition to its projection neurons, the striatum possesses GABAergic and cholinergic interneurons. One motor output pathway of the striatum runs via the pallidum and dorsal thalamic ventral tier nulei to the motor cortex. In addition to this pathway, birds possess a major descending pathway from the basal ganglia to the tectum via the GABAergic nucleus spiriformis lateralis in the pretectum. On hodological and topological grounds, similar nuclei, although not GABAergic, can be found in mammals. Finally, an other striatal motor output is formed by a sequential GABAergic pathway from the basal ganglia via the substantia nigra to the tectum. In conclusion, it appears that the organization of the avian and mammalian basal ganglia is similar rather than different.     

Distributions of GABAA, GABAB, and benzodiazepine receptors in the forebrain and midbrain of pigeons

The single-stranded DNA parvoviruses occur in humans and many species of animals. In general, they are species-specific and capable of producing disease at any stage of life. Parvoviruses have a requirement to replicate in cells in a permissive S-phase of DNA mitosis. The infections may be cytolytic to select cell groups resulting in specific developmental defects or may produce more generalized effects such as anemia, pancytopenia, or hemorrhage. The fetus is at particular risk for damage because of the vast number of cells in active mitosis. The teratogenic effects may be severe, often resulting in fetal death. Infections in childhood and adulthood are more frequently mild to subclinical. Some of the teratogenic effects recognized in animal species have been identified in humans. With increased knowledge of parvovirus effects in animals, more pathogenic effects may be related to human parvoviral disease. The need for vaccination, currently used annually in many domestic animal species, continues to be evaluated for humans.     

A cellular coevolutionary algorithm for image segmentation

Clustering is inherently a difficult problem, both with respect to the definition of adequate models as well as to the optimization of the models. We present a model for the cluster problem that does not need knowledge about the number of clusters a priori . This property is among others useful in the image segmentation domain, which we especially address. Further, we propose a cellular coevolutionary algorithm for the optimization of the model. Within this scheme multiple agents are placed in a regular two-dimensional (2-D) grid representing the image, which imposes neighboring relations on them. The agents cooperatively consider pixel migration from one agent to the other in order to improve the homogeneity of the ensemble of the image regions they represent. If the union of the regions of neighboring agents is homogeneous then the agents form alliances. On the other hand, if an agent discovers a deviant subject, it isolates the subject. In the experiments we show the effectiveness of the proposed method and compare it to other segmentation algorithms. The efficiency can easily be improved by exploiting the intrinsic parallelism of the proposed method.     

IQC‐synthesis with general dynamic multipliers

Analogously to the existing μ‐synthesis tools, we propose an alternative algorithm for the systematic design of robust controllers based on an iteration of standard nominal controller synthesis and integral quadratic constraint (IQC) analysis with general dynamic multipliers. The suggested algorithm enables us to perform robust controller synthesis for a significantly larger class of uncertainties if compared with the existing methods. Indeed, while the classical approaches are restricted to the use of real/complex time invariant or arbitrarily fast time‐varying parametric uncertainties, the IQC framework also offers, for example, the possibility to efficiently handle sector‐bounded and slope restricted nonlinearities or time‐varying parametric uncertainties and uncertain time‐varying time‐delays, both with bounds on the rate‐of‐variation. Secondly, in contrast to the classical approaches, the proposed techniques completely avoid gridding and curve‐fitting. We present new insights that allow us to reformulate the robust IQC analysis LMIs into a standard quadratic performance problem. This enables us to generate suitable initial conditions for each subsequent iteration step. Depending on the size of the problem, this can significantly speed up the synthesis process. The results are illustrated by means of two numerical examples. Copyright © 2013 John Wiley & Sons, Ltd.     

The nearest subclass classifier: a compromise between the nearest mean and nearest neighbor classifier

We present the Nearest Subclass Classifier (NSC), which is a classification algorithm that unifies the flexibility of the nearest neighbor classifier with the robustness of the nearest mean classifier. The algorithm is based on the Maximum Variance Cluster algorithm and, as such, it belongs to the class of prototype-based classifiers. The variance constraint parameter of the cluster algorithm serves to regularize the classifier, that is, to prevent overfitting. With a low variance constraint value, the classifier turns into the nearest neighbor classifier and, with a high variance parameter, it becomes the nearest mean classifier with the respective properties. In other words, the number of prototypes ranges from the whole training set to only one per class. In the experiments, we compared the NSC with regard to its performance and data set compression ratio to several other prototype-based methods. On several data sets, the NSC performed similarly to the k-nearest neighbor classifier, which is a well-established classifier in many domains. Also concerning storage requirements and classification speed, the NSC has favorable properties, so it gives a good compromise between classification performance and efficiency.     

Computer-aided design in the non-ferrous metals industry

Two c.a.d. projects are described aimed at improving tooling design and manufacture in cast and extruded components. A set of design rules have been formulated for die design and manufacture by integrating expertise traditionally spread across different departments. The systems under development should enable the non-ferrous metal industry to reduce its design and costs and simplify design procedures.The engineering user producing 500 new designs each year might save £16 000 per annum through improved design.     

The effects of hippocampal and fimbria–fornix lesions on prepulse inhibition.

The present experiments tested the effects of conventional (dorsal aspiration and electrolytic) and excitotoxic (N-methyl-{d}-aspartate [NMDA]) hippocampal lesions and fimbria-fornix (FF) transection on prepulse inhibition (PPI) of startle response and on open-field activity. Activity was increased by FF transection and by conventional but not excitotoxic hippocampal lesions; complete NMDA lesion increased amphetamine-induced activity. Whereas dorsal hippocampal aspiration lesion disrupted PPI, the phenomenon was not affected by dorsal hippocampal. electrolytic lesion, partial or complete excitotoxic (NMDA) hippocampal lesions, or complete FF transection, which interrupted the cholinergic input to the hippocampus as well as the hippocampal-subicular input to the nucleus accumbens. Systemic apomorphine disrupted PPI in both FF-transected rats and their controls. It is suggested that the hippocampus is essential for PPI disruption rather than for PPI expression. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Scale inhibition of calcium sulfate by a fluidized bed

In a heat exchanger tube of the MSF/FBE the scale inhibiting capability of the fluidized bed with respect to calcium sulfate was investigated. In all experiments at concentration factors between 1 and 2, the hemihydrate solubility line could be passed to a certain extent without scale formation. The ultimately formed scale consisted of anhydrite except at the largest super-saturation for hemihydrate, where hemihydrate was formed.The highest top temperatures were reached when the brine was deaerated and nuclei were excluded. Scale deposition is prevented better by 2 mm glass particles than by 1 mm glass particles. The very first scale layer at the metal surface shows a very poor crystal habit.