Thorium-230 ages of corals and duration of the last interglacial sea-level high stand on oahu, hawaii.

Thorium-230 ages of emergent marine deposits on Oahu, Hawaii, have a uniform distribution of ages from approximately 114,000 to approximately 131,000 years, indicating a duration for the last interglacial sea-level high stand of approximately 17,000 years, in contrast to a duration of approximately 8000 years inferred from the orbitally tuned marine oxygen isotope record. Sea level on Oahu rose to >/=1 to 2 meters higher than present by 131,000 years ago or approximately 6000 years earlier than inferred from the marine record. Although the latter record suggests a shift back to glacial conditions beginning at approximately 119,000 years ago, the Oahu coral ages indicate a near present sea level until approximately 114,000 years ago.

Mass-Spectrometric 230Th-234U-238U Dating of the Devils Hole Calcite Vein.

The Devils Hole calcite vein contains a long-term climatic record, but requires accurate chronologic control for its interpretation. Mass-spectrometric U-series ages for samples from core DH-11 yielded (230)Th ages with precisions ranging from less than 1,000 years (2sigma) for samples younger than approximately 140 ka (thousands of years ago) to less than 50,000 years for the oldest samples ( approximately 566 ka). The (234)U/(238)U ages could be determined to a precision of approximately 20,000 years for all ages. Calcite accumulated continuously from 566 ka until approximately 60 ka at an average rate of 0.7 millimeter per 10(3) years. The precise agreement between replicte analyses and the concordance of the (230)Th/(238)U (234)U/(238)U ages for the oldest samples indicate that the DH-11 samples were closed systems and validate the dating technique in general.

Collection of blood-engorged black flies (Diptera: Simuliidae) and identification of their source of blood.

Blood-engorged black flies were captured by 2 methods: early morning application of a quick knock down insecticide (resmethrin) into tree canopies, and late afternoon to early evening truck trapping. More engorged flies were captured per man-hour with the tree spraying method than with the truck trap. The percentages of females captured by the spraying and truck trap methods that were engorged were 18 and 1.3, respectively. The most commonly engorged species captured were Prosimulium magnum and P. mixtum/fuscum, and Simulium jenningsi and S. venustum (70% of total). Blood sources of 12 black fly species were identified. Mammals comprised 95% of the blood sources identified. The most common hosts were equines (31%), bovines (25%) and raccoons (19%). Seven percent of all meals identified were from mixed sources, of which 43% involved both mammals and birds.

Synchronization of estrus in dairy cows with prostaglandin F2 alpha and estradiol benzoate.

A field study using 322 lactating dairy cows in seven commercial and two university herds was conducted to determine if treatment with estradiol benzoate 40 to 48 h after treatment with prostaglandin F2 alpha would enhance synchronization of estrus. Estrogen treatment tended to increase the proportion of cows in estrus within 5 d (synchronized) after prostaglandin treatment (66.9% versus 58.9%). Of synchronized cows, a greater proportion treated with estrogen (66.9%) were in estrus on d 3 than those not receiving estrogen (48.2%). First service conception rate (31.9%) and interval to second service (35.6 d) were not affected by treatment with estrogen. Milk progesterone was measured in university herds. More cows with milk progesterone concentrations greater than or equal to 8 ng/ml were synchronized (75.4%) than those with less than 8 ng/ml (63.3%). Treatment with estrogen increased synchrony of cows with high progesterone (90.3%) more than prostaglandin alone (60.0%). Based on progesterone concentrations at breeding and 22 to 24 d later, estimated conception rate was 58.7%, and net conception rate based on palpation was 41.3%. Tighter synchrony of estrus can be achieved by using estradiol benzoate 40 to 48 h after prostaglandin. Concentrations of milk progesterone might predict success of treatment.

Identification of a laboratory mating form of the Simulium damnosum Theobald complex in West Africa.

Larvae and pupae of Simulium damnosum s.l. were collected from the Begba rapids on the Mono river. Emerging adults were induced to mate, blood feed and oviposit. Six out of 13 discrete egg batches counted were fertile. The F1 females did not blood feed and thus no F2 eggs were obtained. Larvae from the breeding site and the F1 generation were identified as being the Beffa form of the S. sanctipauli/S. soubrense group. This form appears to be the only member of the S. damnosum complex in West Africa which mates in the laboratory and is almost certainly the same form as that colonized by Simmons and Edman (1982). The mating behaviour of West African S. damnosum s.l. described by several authors is similar to that observed in the Beffa form, and the possibility that earlier reports referred to the Beffa form is discussed.

Prostaglandin in milk, days open, and estrus detection in dairy cows treated with prostaglandin F2 alpha.

Prostaglandin F2 alpha was used to induce estrus in postpartum dairy cows to decrease calving interval and time spent on heat checks. The amount of prostaglandin residue in milk after treatment also was investigated. Twenty-two control cows, checked for heat twice daily, were bred at estrus after 55 days postpartum. Sixty-three cows checked on days 55 to 60 were either bred if in estrus or treated with 30 mg of prostaglandin F2 alpha injected intramuscularly on day 60 and bred at induced estrus or at 75 h posttreatment. Twelve cows were in heat between days 55 and 60 and were bred. Twenty-nine of 51 treated cows were seen in estrus; all of these were bred and 51.7% conceived at this time. Treated cows had fewer days to first service than did controls, but days open were not different, 105.7 versus 101.8. Fertility was similar. Controls required more heat checks than did treated cows (39 to 8.2). Milk from 17 cows at two milkings before and ten milkings after treatment had similar concentrations of prostaglandin (698 +/- 27 pg/ml) except for the first posttreatment milking when prostaglandin concentration almost doubled (1.293 +/- 143 pg/ml).

Modulation of the uptake and retention of estradiol-17beta in the ovine corpus luteum by luteinizing hormone.

The uptake and retention of 3H-estradiol by the ovine corpus luteum (induced by superovulation) was maximal through days 8-12 of the cycle with little or no uptake and retention during luteinization or regression. LH, but not FSH or prolactin, inhibited the uptake and retention of estradiol via stimulation of progesterone synthesis.