The Theoretical Signal Strength Reduction on the Air Force Eastern Test Range

Since both metric and non-metric data are transmitted through a missile\u27s antenna system, assurance of an adequate signal level at the ground sites is essential in planning the range instrumentation support of a launch. For this reason a theoretical signal strength reduction is performed at the Air Force Eastern Test Range before every missile launch. The missile contractor defines the radiation characteristics of each missile-antenna combination in the form of an antenna pattern. The antenna pattern format and the vehicle-antenna coordinate system have been defined by the Inter Range Instrumentation Group. The aspect angles for each tracking site are computed for the theoretical trajectory. These aspect angles are then coupled with the antenna pattern, so that with knowledge of the other parameters, (1) transmitted power; (2) frequency; (3) ground antenna gain, and (4) the polarizations of both antennas, the power received by a ground station can be readily calculated

Dorso-Lateral Frontal Cortex of the Ferret Encodes Perceptual Difficulty during VisualDiscrimination

Visual discrimination requires sensory processing followed by a perceptual decision. Despite a growing understanding of visual areas in this behavior, it is unclear what role top-down signals from prefrontal cortex play, in particular as a function of perceptual difficulty. To address this gap, we investigated how neurons in dorso-lateral frontal cortex (dl-FC) of freely-moving ferrets encode task variables in a two-alternative forced choice visual discrimination task with high- and low-contrast visual input. About two-thirds of all recorded neurons in dl-FC were modulated by at least one of the two task variables, task difficulty and target location. More neurons in dl-FC preferred the hard trials; no such preference bias was found for target location. In individual neurons, this preference for specific task types was limited to brief epochs. Finally, optogenetic stimulation confirmed the functional role of the activity in dl-FC before target touch; suppression of activity in pyramidal neurons with the ArchT silencing opsin resulted in a decrease in reaction time to touch the target but not to retrieve reward. In conclusion, dl-FC activity is differentially recruited for high perceptual difficulty in the freely-moving ferret and the resulting signal may provide top-down behavioral inhibition

EVALUATION OF A FAMILY OF BINOMIAL DETERMINANTS

Abstract. Motivated by a recent work about finite sequences where the n-th term is bounded by n

Early Development of Network Oscillations in the Ferret Visual Cortex

Abstract Although oscillations during development have been characterized in a wide range of neural systems, little is known about the interaction between these network oscillations and neuronal spiking, and the interactions among different oscillation frequencies. Here we recorded the spontaneous and visual-elicited local field potential (LFP) and multi-unit activity (MUA) in the visual cortex of freely-moving juvenile ferrets before and after eye-opening. We found that both the spontaneous and visually-elicited LFP power was increased after eye-opening, especially in higher frequency bands (>30 Hz). Spike LFP phase coupling was decreased for lower frequency bands (theta and alpha) but slightly increased for higher frequencies (high-gamma band). A similar shift towards faster frequencies also occurred for phase-amplitude coupling; with maturation, the coupling of the theta/alpha/beta band amplitude to the delta phase was decreased and the high-gamma amplitude coupling to theta/alpha phase was increased. This shift towards higher frequencies was also reflected in the visual responses; the LFP oscillation became more entrained by visual stimulation with higher frequencies (>10 Hz). Taken together, these results suggest gamma oscillation as a signature of the maturation of cortical circuitry

Resting state network topology of the ferret brain

Resting state functional magnetic resonance imaging (rsfMRI) has emerged as a versatile tool for non-invasive measurement of functional connectivity patterns in the brain. RsfMRI brain dynamics in rodents, non-human primates, and humans share similar properties; however, little is known about the resting state functional connectivity patterns in the ferret, an animal model with high potential for developmental and cognitive translational study. To address this knowledge-gap, we performed rsfMRI on anesthetized ferrets using a 9.4 tesla MRI scanner, and subsequently performed group-level independent component analysis (gICA) to identify functionally connected brain networks. Group-level ICA analysis revealed distributed sensory, motor, and higher-order networks in the ferret brain. Subsequent connectivity analysis showed interconnected higher-order networks that constituted a putative default mode network (DMN), a network that exhibits altered connectivity in neuropsychiatric disorders. Finally, we assessed ferret brain topological efficiency using graph theory analysis and found that the ferret brain exhibits small-world properties. Overall, these results provide additional evidence for pan-species resting-state networks, further supporting ferret-based studies of sensory and cognitive function

The Golden Age of European Cabaret

Program for the second annual RISD Cabaret held in the Cellar in the Pit. Design and layout by Anne Johnson, Susan Sellers and Georgie Stout.https://digitalcommons.risd.edu/liberalarts_cabaret_programs/1001/thumbnail.jp

Financing water resource infrastructure, 1987 September 1

The contents of this paper were drafted from a workgroup report to an Engineering Foundation Conference entitled Financing and Amortizing Water Resources Infrastructure held at Palm Coast, Florida, March 29-April 3, 1987. A slightly different version of this paper appeared in the conference proceedings