A versatile all-channel stimulator for electrode arrays, with real-time control

Over the last few decades, technology to record through ever increasing numbers of electrodes has become available to electrophysiologists. For the study of distributed neural processing, however, the ability to stimulate through equal numbers of electrodes, and thus to attain bidirectional communication, is of paramount importance. Here, we present a stimulation system for multi-electrode arrays which interfaces with existing commercial recording hardware, and allows stimulation through any electrode in the array, with rapid switching between channels. The system is controlled through real-time Linux, making it extremely flexible: stimulation sequences can be constructed on-the-fly, and arbitrary stimulus waveforms can be used if desired. A key feature of this design is that it can be readily and inexpensively reproduced in other labs, since it interfaces to standard PC parallel ports and uses only off-the-shelf components. Moreover, adaptation for use with in vivo multi-electrode probes would be straightforward. In combination with our freely available data-acquisition software, MeaBench, this system can provide feedback stimulation in response to recorded action potentials within 15 ms

Predatory Insects and Spiders From Suburban Lawns in Lexington, Kentucky

Predatory arthropods were caught in pitfall traps in suburban lawns in Lexington, Kentucky. The relative abundance of species of Lycosidae, Carabidae, and Staphylinidae was compared in Kentucky bluegrass and tall fescue turf. Nine species of Lycosidae were collected from both the bluegrass and tall fescue lawns. More species or phena of Carabidae were collected from bluegrass than from tall fescue turf. More than 40 species or phena of staphylinids were collected from each grass habitat. Both Kentucky bluegrass and tall fescue are inhabited by an abundant and diverse array of predatory arthropods

Ten polymorphic microsatellite primers in the tropical tree caimito, Chrysophyllum cainito (Sapotaceae).

UnlabelledPremise of the studyWe developed microsatellite primers for the tropical tree Chrysophyllum cainito (Sapotaceae) to determine the native range of the species, investigate the origin of cultivated populations, and examine the partitioning of genetic diversity in wild and cultivated populations. •Methods and resultsWe developed 10 polymorphic primers from C. cainito genomic DNA libraries enriched for di-, tri-, and tetranucleotide repeat motifs. The loci amplified were polymorphic in samples collected from Jamaica and Panama. The number of alleles per locus ranged from two to 10 and three to 12, while observed heterozygosities ranged from 0.074 to 0.704 and 0.407 to 0.852 in Jamaica and Panama, respectively. •ConclusionsThe microsatellite primers will be useful in future population genetic studies as well as those aimed at understanding the geographic origin(s) of wild and cultivated populations

Persistent dynamic attractors in activity patterns of cultured neuronal networks

Three remarkable features of the nervous system—complex spatiotemporal patterns, oscillations, and persistent activity—are fundamental to such diverse functions as stereotypical motor behavior, working memory, and awareness. Here we report that cultured cortical networks spontaneously generate a hierarchical structure of periodic activity with a strongly stereotyped population-wide spatiotemporal structure demonstrating all three fundamental properties in a recurring pattern. During these "superbursts," the firing sequence of the culture periodically converges to a dynamic attractor orbit. Precursors of oscillations and persistent activity have previously been reported as intrinsic properties of the neurons. However, complex spatiotemporal patterns that are coordinated in a large population of neurons and persist over several hours—and thus are capable of representing and preserving information—cannot be explained by known oscillatory properties of isolated neurons. Instead, the complexity of the observed spatiotemporal patterns implies large-scale self-organization of neurons interacting in a precise temporal order even in vitro, in cultures usually considered to have random connectivity

How Greater Travel Distance Due to Clinic Closures Reduced Access to Abortion in Texas

Population Research Cente

Archaeological Survey of the Covel Gardens Landfill Area in San Antonio, Bexar County, Texas

In March 1990, archaeologists from the Center for Archaeological Research, The University of Texas at San Antonio, conducted a surface survey and subsurface testing at a locality proposed for a landfill by Waste Management of North America, Inc. Survey and testing activities were performed in order to locate and evaluate any archaeological remains which might be affected by landfill construction and operation. In addition, a private collection of artifacts originating from the project area was documented. Prehistoric archaeological remains were encountered in the western portion of the study area, and a new site number was designated for these remains, 41 BX 873. Because of prior disturbance to this site, we recommend that no further investigation is needed

Archaeological Survey of Property for the Proposed Eagle Pass International Bridge, Maverick County, Texas

In May 1990, archaeologists for the Center of Archaeological Research, The University of Texas at San Antonio conducted a surface survey and subsurface testing program. at the site of the proposed Eagle Pass international bridge. The survey was conducted for Groves and Associates, Inc., consulting engineers and project planners, for the City of Eagle Pass. Survey and testing activities were performed in order to locate and evaluate any archaeological remains which might be affected by construction of the bridge and associated facilities. In addition, archival research was conducted at the Eagle Pass library and county courthouse in order to assess potential archaeological resources in the area of the proposed bridge site. The project area has been much disturbed by road, railroad, and water treatment facility constructions. No significant prehistoric or historic archaeological remains were identified during the survey and testing. However further machine and hand excavations within the river terraces to examine for deeply buried cultural deposits and conduct geomorphological recording will be required

Unemployment Insurance: Policies and Principles of Disqualification and Disentitlement for Benefits

Ever since the 1940 amendment to the BNA Act\u27 which gave exclusive jurisdiction in relation to unemployment insurance to Parliament, the thrust of Canada\u27s unemployment compensation system and the basis for its eligibility conditions has been that the claimant must be unemployed through no fault of his own.2 The primary purpose of the Unemployment Insurance Act, 19713 was put succinctly in a recent decision of the Umpire: ... it is not the function of the Unemployment Insurance Act to provide public welfare, but rather to provide aid of a temporary nature to a claimant who is actively seeking work and capable of performing work of a nature which may be available and who through no fault of his own is unable to find it. CUB 34474 Because of this limited legislative objective, unemployment insurance cannot be seen as a panacea for all the ills of economic disadvantage, but is only part of a broader spectrum of social compensation, social assistance, old age pensions and disability relief programs. It is not surprising, therefore, that all the unemployment insurance acts since 1940 have had provisions restricting eligibility in such cases as: (1) voluntary separation 5, (2) loss of employment through misconduct6 ; (3) unavailability for work7 ; and (4) refusal of suitable employment8

Archaeological Survey of the Children\u27s Park at the Victoria Municipal Park, Victoria, Texas

During May 1989, personnel from the Center for Archaeological Research, The University of Texas at San Antonio, conducted a pedestrian survey and shovel testing of the area proposed for development of a children\u27s park, a project of the City of Victoria Parks and Recreation Department. The survey was intended to locate any archaeological remains which might be impacted by construction of the children\u27s park. No archaeological sites were identified during the project, and it is recommended that no further archaeological investigations are needed