Geochemical exploration of rare earth element resources in highland karstic bauxite deposits in the Sierra de Bahoruco, Pedernales Province, Southwestern Dominican Republic.

This study investigates the geochemical characteristics of rare earth elements (REEs) in highland karstic bauxite deposits located in the Sierra de Bahoruco, Pedernales Province, Dominican Republic. These deposits, formed through intense weathering of volcanic material, represent a potentially valuable REE resource for the nation. Surface and subsurface soil samples were analyzed using portable X-ray fluorescence (pXRF) and a NixPro 2 color sensor validated with inductively coupled plasma optical emission spectrometry (ICP-OES).

Male 11-ketotestosterone levels change as a result of being watched in Siamese fighting fish, Betta splendens.

This study investigated the effects of nesting status and the presence of an audience on 11-ketotestosterone (11KT) levels in male Siamese fighting fish, Betta splendens. Prior studies have demonstrated that both nesting status, an indicator of territory-holding power and reproductive state, and the sex of a conspecific audience lead to differences in male behavior during aggressive encounters. Since behavioral changes have already been demonstrated, we chose to investigate whether 11KT levels were also influenced by nesting status and audience presence as 11KT both stimulates, and is stimulated by, reproductive and aggressive behaviors in male teleosts.

Habituation and development of response specificity to a sign stimulus: male preference for female courtship posture in stickleback.

I examined biased patterns of habituation that occur when reproductive male three-spined stickleback, Gasterosteus aculeatus, respond to a choice of two dummy females, one displaying the head-up posture of a sexually receptive female and an otherwise identical dummy lacking this sign stimulus (i.e. a dummy in a 'neutral' horizontal posture).

The effectiveness of doramectin pour-on in the control of gastrointestinal nematode infections in cow-calf herds.

Two field studies were conducted in the USA to determine the efficacy of a single strategically-timed dose of doramectin pour-on in the control of gastrointestinal nematodosis in beef cow-calf herds and the resultant effects on calf productivity. One study was carried out between May and October 1996 in a spring-calving herd at a site located in Idaho (ID) and the other between January and July 1997 in a fall-calving herd at a site located in Mississippi (MS). In each study, cow-calf pairs were randomly allotted by sex of calf to pastures and one of two treatment groups (doramectin pour-on at the recommended dose rate of 500 microg/kg body weight or untreated control).

Pavlovian conditioning of agonistic behavior in male threespine stickleback (Gasterosteus aculeatus).

The red coloration of male stickleback (Gasterosteus aculeatus) possesses signal value in male-male interactions. Therefore, it was predicted that males would learn to associate a red signal more readily than a green signal with a conspecific rival in a Pavlovian conditioning experiment. Males were presented red and green signal lights where one signal was always paired with presentation of a rival (excitatory conditioned stimulus, CS+) and one signal was never paired with presentation of a rival (nonreinforced stimulus, CS-).