Williams College

About: Williams College is a education organization based out in Williamstown, Massachusetts, United States. It is known for research contribution in the topics: Population & Politics. The organization has 2257 authors who have published 5015 publications receiving 213160 citations. The organization is also known as: Williams.

The role of the middle cerebellar peduncle in acquisition and retention of the rabbit’s classically conditioned nictitating membrane response

Abstract: In the present study, the middle cerebellar peduncles of 20 rabbits were lesioned before or after the left nictitating membrane/eyelid response was classically conditioned. Naive animals with completely destructed peduncles were unable to learn; in trained animals, the CRs were abolished using tones, lights, tactile stimulation, or pontine stimulation as conditioned stimuli. These results support the hypothesis that conditioned stimulus information is projected to the cerebellum via mossy fibers in the middle cerebellar peduncle during classical conditioning of discrete, somatic responses.

Delay and acceleration of puberty in female mice by urinary chemosignals from other females.

Abstract: A sequence of 7 experiments tested various aspects of the acceleration and delay of sexual maturation in young female mice as affected by cues from other females: Singly caged females produce the maturation-delaying chemosignal when exposed to urine from grouped females. Urine from females housed 3 or more/cage produces delays in puberty for young females. Urine from females in estrus accelerates puberty in young females relative to untreated controls or urine from non-estrous females. The delay-of-maturation phenomenon in female mice is not affected by reproductive history, cross-fostering of pups, or varying the cagemates according to whether they are sibs or nonsibs. Taken together these and previous findings suggest that female mice excrete, in their urine, a series of chemicals which act as signals regarding the adequacy of reproductive conditions.

Reimagining South American coasts: unveiling the hidden invasion history of an iconic ecological engineer

Abstract: Fil: Bortolus, Alejandro. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Nacional Patagonico; Argentina

Stratigraphy and Paleoecology of the Richmond Group in Southeastern Indiana

Abstract: The Richmond Group (Upper Ordovician) in southeastern Indiana is subdivided into rock-stratigraphic units (formations and members) and biostratigraphic units (assemblage zones). The formations and members established by earlier workers on the basis of faunal zones are either redefined as mappable rock units or discarded. A newly proposed formation replaces the lower three “formations,” Arnheim, Waynesville, and Liberty, which are based on paleontologic criteria and are lithologically indistinguishable. The new unit consists of thin layers of fossiliferous and barren limestone alternating with layers of calcareous shale. Two barren shale beds in conjunction with silicified fossil and pyritic limestone horizons are used to subdivide the new unit for a quantitative study of its lithologic variation. The Whitewater Formation above is redefined and subdivided into five rock units on the basis of lithology: (1) a lower unnamed member of massive earthy limestone, (2) a black carbonaceous shale bed, (3) the lower Saluda Member, which is a northward thinning wedge of mud-cracked slabby limestone with layers of massive dolomitic limestone at the base and top, (4) the upper Saluda Member, lithologically similar to the lower wedge but separated from it by a layer of massive dolomitic limestone, and (5) an upper unnamed member of massive earthy limestone. Four faunal assemblage zones are recognized in the newly proposed unit: (1) Resserella meeki, (2) Leptaena richmondensis, (3) Sowerbyella rugosus, and (4) Strophomena planumbona. The assemblage zones become thin and pinch out to the south, and their boundaries cross lithologic marker horizons within the newly proposed rock unit. The Homotrypa wortheni and Tetradium minus assemblage zones within the Whitewater Formation are split into upper and lower parts by the barren Saluda Member. The numbers of individuals in each species are counted in small unit areas and are statistically analyzed to determine the distribution of species within the assemblage zones and the geographic extent of the zones. The following interpretation of depositional environments is based on the distribution of the rock types and faunal assemblage zones. The lower unit of the Richmond Group was deposited in a shallow, inner sub-littoral, marine environment. The Whitewater Formation was formed during the regression and transgression of a shoal area with the lower and upper unnamed members representing the submerged mud flats, and the Saluda Member, the exposed mud flats.