University of Wisconsin-Madison

About: University of Wisconsin-Madison is a education organization based out in Madison, Wisconsin, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 108707 authors who have published 237594 publications receiving 11883575 citations.

Depression: perspectives from affective neuroscience.

Abstract: Depression is a disorder of the representation and regulation of mood and emotion. The circuitry underlying the representation and regulation of normal emotion and mood is reviewed, including studies at the animal level, human lesion studies, and human brain imaging studies. This corpus of data is used to construct a model of the ways in which affect can become disordered in depression. Research on the prefrontal cortex, anterior cingulate, hippocampus, and amygdala is reviewed and abnormalities in the structure and function of these different regions in depression is considered. The review concludes with proposals for the specific types of processing abnormalities that result from dysfunctions in different parts of this circuitry and offers suggestions for the major themes upon which future research in this area should be focused.

Deconstructing multiantenna fading channels

Abstract: Accurate and tractable channel modeling is critical to realizing the full potential of antenna arrays in wireless communications. Current approaches represent two extremes: idealized statistical models representing a rich scattering environment and parameterized physical models that describe realistic scattering environments via the angles and gains associated with different propagation paths. However, simple rules that capture the effects of scattering characteristics on channel capacity and diversity are difficult to infer from existing models. We propose an intermediate virtual channel representation that captures the essence of physical modeling and provides a simple geometric interpretation of the scattering environment. The virtual representation corresponds to a fixed coordinate transformation via spatial basis functions defined by fixed virtual angles. We show that in an uncorrelated scattering environment, the elements of the channel matrix form a segment of a stationary process and that the virtual channel coefficients are approximately uncorrelated samples of the underlying spectral representation. For any scattering environment, the virtual channel matrix clearly reveals the two key factors affecting capacity: the number of parallel channels and the level of diversity. The concepts of spatial zooming and aliasing are introduced to provide a transparent interpretation of the effect of antenna spacing on channel statistics and capacity. Numerical results are presented to illustrate various aspects of the virtual framework.

Sulfolobus : A new genus of sulfur-oxidizing bacteria living at low pH and high temperature

Abstract: Sulfolobus is a new genus of bacteria characterized as follows: 1. generally spherical cells producing frequent lobes; 2. facultative autotrophy with growth on sulfur or on a variety of simple organic compounds; 3. unusual cell wall structure devoid of peptidoglycan; 4. acidophilic, pH optimum of 2–3 and range from 0.9–5.8; 5. thermophilic with temperature optimum of 70–75°C and range from 55–80°C (one strain grew at 85°C). The DNA base composition of five strains was determined by cesium chloride density gradient centrifugation and found to be 60–68% guanine plus cytosine. Sulfolobus apparently has no close relationship with any previously described bacteria, either heterotrophic or autrotrophic. Techniques are presented for distinguishing Sulfolobus from Thermoplasma, another genus of acidophilic thermophilic spherically shaped organisms. Sulfolobus has been isolated from a variety of natural acidic thermal habitats, both terrestrial and aquatic. Most isolations have been from habitats in Yellowstone National Park, but strains were also isolated from Italy, Dominica and El Salvador. It is suggested that Sulfolobus may be an important geochemical agent in the production of sulfuric acid from sulfur in high temperature hydrothermal systems.

Mossy fiber synaptic reorganization in the epileptic human temporal lobe.

Abstract: The distribution of the mossy fiber synaptic terminals was examined using the Timm histochemical method in surgically excised hippocampus and dentate gyrus from patients who underwent lobectomy of the anterior part of the temporal lobe for refractory partial complex epilepsy The dentate gyrus of epileptic patients demonstrated intense Timm granules and abundant mossy fiber synaptic terminals in the supragranular region and the inner molecular layer In contrast, the dentate gyrus of presenescent nonepileptic primates demonstrated no Timm granules in the supragranular region In nonepileptic senescent primates, occasional very sparse supragranuler Timm granules were observed that were easily distinguished from the dense pattern observed in association with human epilepsy The results are morphological evidence of mossy fiber synaptic reorganization in the temporal lobe of epileptic humans, and suggest the intriguing possibility that mossy fiber sprouting and synaptic reorganization induced by repeated partial complex seizures may play a role in human epilepsy