Summary. The fatty-acid composition of follicular fluid from small and large developing follicles was analysed and the effects of saturated and unsaturated fatty acids on spontaneous breakdown of germinal vesicles were investigated. Fatty acids were bound to bovine serum albumin and cultured with occytes at 100 \g=m\mol/l. Linoleic acid (18:2) was the only fatty acid tested that significantly inhibited breakdown of germinal vesicles (P < 0\m=.\01). The effect was dose-dependent and was greatest at 50 \g=m\molfatty acid/1 (% breakdown of control, 81\m=.\1\ m=+-\6\m=.\8 vs. 50\g=m\mol linoleic acid/1, 35\m=.\4\ m=+-\7\ m=. \ 3; P < 0\m=.\02). Linoleic acid was the major fatty acid, constituting about a third of the total fatty acid in the follicular fluid; followed by 18\m=.\9 \ m=+-\ 1\m=.\0%and 16\m=.\9 \ m=+-\ 1\m=.\3%oleic acid (18:1) in small and large follicles, respectively. Saturated fatty acids accounted for <30% of the total fatty acid composition. There was a marked absence of tetraenoic acids in small and large follicles. Proportions of linoleic acid were significantly lower in follicular fluid from large follicles (31\m=.\1 \m=+-\1\m=.\2%of total fatty acid) than from small follicles (34\m=.\8 \m=+-\0\m=.\7%of total fatty acid) (P < 0\m=.\05) and there was a significant inverse correlation between follicle diameter and percentage of linoleic acid in the follicular fluid (r= \m=-\0\m=.\6966; P < 0\m=.\05). There was no significant alteration in any other fatty acid during follicular development. The results suggest that (i) a critical relative concentration of linoleic acid may be required for maintenance of meiotic arrest in bovine oocytes and (ii) the decline in the proportion of linoleic acid during follicular development may contribute to the relief of the inhibition of breakdown of germinal vesicles.
The Gulf killifish (Fundulus grandis) is a euryhaline fish found in coastal marsh along the entire of Gulf of Mexico and southern Atlantic of coast of the United States. The objective of this study was to investigate the effects of salinity on embryogenesis in the Gulf killifish. Four recirculation systems at salinities of 0.4, 7, 15, and 30 g/L were maintained at a static temperature with flow-through trays, containing embryos (n = 39) placed in triplicate into each system. Throughout embryogenesis, the rate of development, ammonia and urea excretion, and heart rate were monitored. Percent hatch was recorded, and morphological parameters were measured for larvae at hatch. As salinity was increased, the rate of embryogenesis decreased. Salinity significantly affected percent hatch with an 80.0% ± 2.6% for 7 g/L and 39.1 ± 4.3, 45.4 ± 4.5, and 36.3% ± 12.0% for 0.4, 15, and 30 g/L, respectively. Salinity and stage of development significantly affected production of ammonia and urea. As salinity increased, the dominate metabolite end product changed from urea to ammonia. However, the 15 g/L salinity treatment had the two highest levels of urea recorded. Heart rate was unaffected by salinity but increased throughout embryogenesis and remained constant once embryos reached stages where hatching has been recorded. While mean total length was not affected by salinity, embryos incubated in 30 g/L produced larvae with significantly thicker body depth at hatch. The 0.4, 7, and 15 g/L salinity treatments all had similar mean hours to hatch. The 30 g/L treatment resulted in a significantly longer mean time to hatch and smaller body cavity area at hatch.
Summary The Niobrara gas play in eastern Colorado, northwestern Kansas, and western Nebraska is a successful economic development involving an integrated, interdisciplinary exploration and exploitation strategy. This comprehensive study of the Niobrara formation gives a concise description of methods for exploration, development, production and evaluation of the Niobrara reservoirs. Introduction In 1912, the Osborne and Dunn Co. encountered a strong flow of gas in the Niobrara formation while drilling the Goodland No. 1 well (Sec. 24-T8S-R40W) near the town of Goodland, KS. The well subsequently was plugged and abandoned. In the 1930's and 1940's, several small Niobrara gas wells were drilled in the Goodland field area by Industrial Gas Co. and others for local use only. The Beecher Island field discovery well was Midfields No. 1 well (Sec. 14-T2S-R43W) in Yuma County, CO, drilled in 1919 by the Midfields Oil Co. It had estimated flow rates of up to 2 MMcf/D (57×10-3 m3/d) of gas. In the 1920's, four additional Niobrara wells were drilled in Beecher Island; however, connection to a pipeline could not be justified. By 1970, two of the four dry holes drilled to deeper formations had gas shows while penetrating the Niobrara formation. Following a study in 1972 of the known gas shows in the Beecher Island field, Midlands Gas Corp. and Mountain Petroleum Corp. air-drilled six wells in Beecher Island. Five were completed without stimulation as producers and then were connected to a pipeline. The wells averaged 20 Mcf/D (565 m /d) each, which at $0.35/Mcf ($0.35/30 m) was uneconomical. However, they proved the existence of significant gas reserves. Further investigation revealed many resistivity log anomalies and reported gas shows in the Niobrara of eastern Colorado and western Kansas. However, the play began when, in early 1974, the new high-quality foam fracture stimulation process was used for the completion of the Beecher Island field State 1-29 well (Sec. 29-T2S-R42W). The well had a prestimulation drillstem test rate of only 5.6 Mcf/D (160 m3/d). After the treatment, it had an initial potential of 721 Mcf/D (20×10 M /d), with a sustained rate of more than 150 Mcf/D (4250 m3/d). The play now extends from Chadron, NE, and south to Kit Carson County, CO (Fig. 1). The major concentration of drilling remains in the original producing area in Yuma County, CO, and in Cheyenne and Sherman counties, KS. Since 1974, 919 Niobrara wells have been drilled, of which 454 are producers in more than 60 fields; 465 wells are dry holes. At this time, very few fields are developed fully. Geology and Gas Origin The Niobrara formation chalks were deposited during the last major transgression of the western interior Cretaceous sea, which extended from the Gulf of Mexico to the Arctic Ocean. The lower member of the Niobrara is the Fort Hays, which is 40 to 85 ft (12 to 25 m) thick. The upper member is the Smoky Hill, which averages 600 ft (180 m) (Fig. 2). JPT P. 2863^
This study simulated terrestrial incubation and measured rates of embryogenesis, nitrogen elimination, heart rate, lactate production, maximum length of time a hatch could be delayed and developmental responses of terrestrially incubated Gulf killifish Fundulus grandis embryos at temperatures ranging from 20 to 30° C. Temperature had a positive relationship with rate of embryogenesis, but a negative relationship with extent of extended incubation. The 30° C treatment reached embryonic maturity 6 days before the 20° C treatment. Embryos hatched between intervals of 240 and 336, 144 and 288, 96 and 240 and 96 and 192 h after reaching developmental maturity for the 20, 23, 26 and 30° C treatments. Significantly higher concentrations of total nitrogen, in the form of ammonia and urea, were recorded in the 20 and 30° C treatments. While temperature significantly influenced lactate and ATP concentrations, no significant influence of time of incubation was detected. Terrestrial embryos displayed an ability to develop quickly during embryogenesis and prolong incubation for an extended period of time after reaching embryonic maturity. This adaptation may be a life-history trait used to minimize asynchronous hatching, cannibalism and cohort size heterogeneity.
Natural gas is being developed and produced in the Bowdoin Dome area from shallow, low-pressure, low-permeability reservoirs that were previously noncommercial. Reservoirs are dominantly thin, discontinuous, shaly siltstone and sandstone laminae and beds which cannot be distinguished on conventional logs. They require stimulation to provide commercial flow rates and necessitate more sophisticated evaluation methods than do conventional reservoirs. Introduction This paper reviews the geologic, technological, and economic parameters that have contributed to the development of natural gas reserves in the recently expanded portions of the Bowdoin Dome area. The technology and methods discussed are those used by Midlands Gas Corp., a subsidiary of Kansas-Nebraska Natural Gas Co. Inc, and may differ from those of other operators in the area. The Bowdoin Dome is a very large structural uplift located in eastern Phillips and western Valley counties in north-central Montana (Fig. 1). Natural gas was first discovered on the structure in 1913 in a shallow well drilled for water. The central part of the structure was developed through the 1950's with natural openhole completions in wells drilled where the pay zones are shallower. With the advent of improved completion techniques and increased gas prices in the 1970's, the field was expanded in size to more than 600 sq miles (1550 km2). Natural gas is being produced from low-permeability, low-pressure reservoirs at depths less than 2,000 ft (610 m). The pay zones consist of thin, discontinuous laminae and beds of siltstone and sandstone, and a more persistent limestone bed. These beds are enclosed in a thick sequence of offshore marine shale of late Cretaceous age. The gas is of biogenic origin and was generated in the surrounding marine shales. One major problem existed with the most recent expansion. The development program was designed to be run concurrently with the construction of a large gathering facility. The purpose was to increase economic viability and to develop a more efficient optimization of stimulation techniques and spacing criteria. However, delays in the approval of the pipeline facility forced the operators to use technology evolved in other areas. Specifically, the development of similar shallow gas accumulations in southeastern Alberta was used as an analog for the original treatment designs and 640-acre (2.6 x 10(6) m2) spacing. Most of the development in the Bowdoin Dome area was completed before the final construction of a gathering facility. Therefore, information on the adequacy of the initial development design has become available only recently. Structure The Bowdoin Dome is a very large, nearly oval arch which has structural closure of about 700 ft (200 m) on top of the Upper Cretaceous Greenhorn lime. Most of the new development concentrates on a north/northwest-trending nose that extends across the Canadian border.
A key challenge in conservation biology is to identify natural populations with compromised health and identify causative agents. However, wildlife are exposed to a complex matrix of natural and anthropogenic stressors such that identifying particular agents of distress is difficult. Yet, establishing cause and effect between human-induced environmental changes and adverse health is necessary to guide conservation planning. Transcriptome profiling, with thoughtful experimental design and appropriate metadata, is useful for establishing cause and effect between exposures to environmental stressors and adverse health outcomes. Here we describe transcriptome profiling and associated paradigms that are useful for wildlife health assessment and conservation planning, with particular emphasis on pollution. We emphasize that these tools are important for testing hypotheses about causative agents of distress, but also for generating new hypotheses about causes and consequences. We outline two case studies that highlight attributes of transcriptomics tools and approaches that add value for conservation practitioners.
A composite model for gas well performance evaluation and prediction has proven successful and efficient in analyzing gas wells producing from low permeabili ty tight gas formations.By employing analytic methods which model reservoir and fracture behavior, a model has been constructed which is capable of automatic regression for the descriptive reservoir parameters.The model is designed to treat producing and shut-in conditions ranging from a simple four-point test to several years of online pressure-production history.Once historymatched parameters are determined, the model is then capable of projecting future performance.
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