Multi-Finger Haptic Rendering of Deformable Objects, In. Tenth Eurographics Symposium on Virtual Environments

The present paper describes the integration of a multi-finger haptic device with deformable objects in an interactive environment. Repulsive forces are synthesized and rendered independently for each finger of a user wearing a Cybergrasp force-feedback glove. Deformation and contact models are based on mass-spring systems, and the issue of the user independence is dealt with through a geometric calibration phase. Motivated by the knowledge that human hand plays a very important role in the somatosensory system, we focused on the potential of the Cybergrasp device to improve perception in Virtual Reality worlds. We especially explored whether it is possible to distinguish objects with different elasticities. Results of performance and perception tests are encouraging despite current technical and computational limitations

The primary headaches: genetics, epigenetics and a behavioural genetic model

The primary headaches, migraine with (MA) and without aura (MO) and cluster headache, all carry a substantial genetic liability. Familial hemiplegic migraine (FHM), an autosomal dominant mendelian disorder classified as a subtype of MA, is due to mutations in genes encoding neural channel subunits. MA/MO are considered multifactorial genetic disorders, and FHM has been proposed as a model for migraine aetiology. However, a review of the genetic studies suggests that the FHM genes are not involved in the typical migraines and that FHM should be considered as a syndromic migraine rather than a subtype of MA. Adopting the concept of syndromic migraine could be useful in understanding migraine pathogenesis. We hypothesise that epigenetic mechanisms play an important role in headache pathogenesis. A behavioural model is proposed, whereby the primary headaches are construed as behaviours, not symptoms, evolutionarily conserved for their adaptive value and engendered out of a genetic repertoire by a network of pattern generators present in the brain and signalling homeostatic imbalance. This behavioural model could be incorporated into migraine genetic research

Current and prospective pharmacological targets in relation to antimigraine action

Migraine is a recurrent incapacitating neurovascular disorder characterized by unilateral and throbbing headaches associated with photophobia, phonophobia, nausea, and vomiting. Current specific drugs used in the acute treatment of migraine interact with vascular receptors, a fact that has raised concerns about their cardiovascular safety. In the past, α-adrenoceptor agonists (ergotamine, dihydroergotamine, isometheptene) were used. The last two decades have witnessed the advent of 5-HT1B/1D receptor agonists (sumatriptan and second-generation triptans), which have a well-established efficacy in the acute treatment of migraine. Moreover, current prophylactic treatments of migraine include 5-HT2 receptor antagonists, Ca2+ channel blockers, and β-adrenoceptor antagonists. Despite the progress in migraine research and in view of its complex etiology, this disease still remains underdiagnosed, and available therapies are underused. In this review, we have discussed pharmacological targets in migraine, with special emphasis on compounds acting on 5-HT (5-HT1-7), adrenergic (α1, α2, and β), calcitonin gene-related peptide (CGRP 1 and CGRP2), adenosine (A1, A2, and A3), glutamate (NMDA, AMPA, kainate, and metabotropic), dopamine, endothelin, and female hormone (estrogen and progesterone) receptors. In addition, we have considered some other targets, including gamma-aminobutyric acid, angiotensin, bradykinin, histamine, and ionotropic receptors, in relation to antimigraine therapy. Finally, the cardiovascular safety of current and prospective antimigraine therapies is touched upon

Competition for food in swans: an experimental test of the truncated phenotype distribution

1. Ideal free models for unequal competitors predict a truncated competitor phenotype distribution among patches when relative payoffs of phenotypes vary across patches. Partial truncation is expected under field conditions. This prediction was tested in a field experiment with an overwintering population of mute swans (Cygnus olor). 2. Two food patches were generated in which adult and subadult swans were expected to have different relative success. In one patch ('clumped'), pieces of bread were thrown over a small area on the water surface. In the other patch, pieces of bread were scattered over a larger area. 3. When only one patch was offered at a time (no choice situation), adult swans were more successful than subadult swans in the 'clumped' patch, but were similarly successful in the 'scattered' patch. Relative payoffs of adult and subadult swans differed significantly between patches. 4. When the two patches were offered simultaneously, black-headed gulls (Larns ridibundus) competed with the swans to a considerable extent in some replicates. The gulls appeared to be the poorest competitors. They snatched more bread in the scattered than in the clumped patch. Both classes of swans avoided the scattered patch but not the clumped patch with increasing competition from gulls. Gulls preferred the scattered patch and swans increasingly preferred the clumped patch under gull competition, creating a partially truncated distribution. 5. Without the four replicates in which the gulls had consumed more than 25% of the bread, the percentage of adult swans that chose the clumped patch was significantly higher than the percentage of subadult swans that chose that patch. This is the first experimental verification of a partially truncated phenotype distribution. Subadult swans significantly preferred the scattered patch whereas adults tended to prefer the clumped patch. This distribution was predicted from the 'no choice' experiment, where competition by gulls had been similarly weak

Entwicklung und Erprobung eines Verfahrens zur Verwertung und thermischen Nutzung von Rest- und Abfallstoffen aus der Abgas- und Abwasserreinigung durch Einblasen in metallurgische Schmelzreaktoren Abschlussbericht zur Phase 3

SIGLEAvailable from TIB Hannover: F01B433 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDeutsche Bundesstiftung Umwelt, Osnabrueck (Germany)DEGerman