Geologic settings of lignite in the Wilcox Group of east-central Texas and the Jackson Group of South Texas

1989 ◽  
pp. 5-16
Author(s):  
W. B. Ayers
Keyword(s):  
South Texas ◽  
East Central ◽  
Central Texas

Evidence for rapid phenotypic and behavioural shifts in a recently established cavefish population

2019 ◽  
Author(s):  
Suzanne E McGaugh ◽  
Sam Weaver ◽  
Erin N Gilbertson ◽  
Brianna Garrett ◽  
Melissa L Rudeen ◽  
...  
Keyword(s):  
Extreme Environments ◽  
Time Frame ◽  
South Texas ◽  
Astyanax Mexicanus ◽  
North East ◽  
Surface Population ◽  
Cave Population ◽  
Cave Environment ◽  
Central Texas ◽  
Recent Origin

Abstract Cave colonization offers a natural laboratory to study an extreme environmental shift, and diverse cave species from around the world often have converged on robust morphological, physiological and behavioural traits. The Mexican tetra (Astyanax mexicanus) has repeatedly colonized caves in the Sierra de El Abra and Sierra de Guatemala regions of north-east Mexico ~0.20–1 Mya, indicating an ability to adapt to the cave environment. The time frame for the evolution of these traits in any cave animal, however, is poorly understood. Astyanax mexicanus from the Río Grande in South Texas were brought to Central Texas beginning in the early 1900s and colonized underground environments. Here, we investigate whether phenotypic and behavioural differences have occurred rapidly between a surface population and a geographically proximate cave population, probably of recent origin. Fish from the cave and surface populations differ significantly in morphological traits, including coloration, lateral line expansion and dorsal fin placement. Striking behavioural shifts in aggression, feeding and wall-following have also occurred. Together, our results suggest that morphological and behavioural changes accompanying cave colonization can be established rapidly, and this system offers an exciting and unique opportunity for isolating the genetic and environmental contributions to colonization of extreme environments.

Peanut Response to Ethalfluralin, Pendimethalin, and Trifluralin Preplant Incorporated1

2003 ◽  
Vol 30 (1) ◽  
pp. 34-37 ◽  
Author(s):  
P. A. Dotray ◽  
J. W. Keeling ◽  
W. J. Grichar ◽  
E. P. Prostko ◽  
R. G. Lemon ◽  
...  
Keyword(s):  
Field Experiments ◽  
South Texas ◽  
Stand Establishment ◽  
West Texas ◽  
Central Texas ◽  
Incorporation Method ◽  
Dinitroaniline Herbicides

Abstract Field experiments were conducted at Yoakum (south Texas) in 1996 and 1997, Comanche (central Texas) in 1998, and Lamesa (west Texas) in 1998 and 1999 to evaluate peanut tolerance to dinitroaniline herbicides. At Lamesa, ethalfluralin at 0.63 or 0.84 kg/ha, pendimethalin at 0.56 or 0.84 kg/ha, and trifluralin at 0.56 or 0.71 kg/ha were applied preplant incorporated (PPI), and at Yoakum and Comanche, ethalfluralin and pendimethalin were applied PPI at 0.67, 0.84, 1.12, and 1.68 kg/ha. There were no differences in stand establishment or yield for any treatment at Lamesa, Comanche, or Yoakum. Similarly, canopy stature was not affected at Lamesa nor was grade affected at Comanche or Yoakum. At Lamesa, yields by herbicide averaged across rates, incorporation methods, and years ranged from 4530 to 4920 kg/ha; by rate averaged across herbicides, incorporation methods, and years was 4600 to 4750 kg/ha; and by incorporation method averaged across herbicides, rates, and years was 4580 to 4770 kg/ha. At Yoakum and Comanche, yields by herbicide were 2640 and 2950 kg/ha, respectively, when averaged across rates; and by rate they ranged from 2630 to 2990 kg/ha when averaged across herbicides. These data indicate peanut has tolerance (safety) to ethalfluralin, pendimethalin, and trifluralin applied PPI in Texas.

Influence of Johnsongrass (Sorghum halepense) Density and Period of Competition on Cotton Yield

Weed Science ◽  
1987 ◽  
Vol 35 (1) ◽  
pp. 63-67 ◽  
Author(s):  
David C. Bridges ◽  
James M. Chandler
Keyword(s):  
Yield Loss ◽  
Sorghum Halepense ◽  
Yield Potential ◽  
Yield Response ◽  
Cotton Yield ◽  
Critical Periods ◽  
East Central ◽  
Central Texas ◽  
Competition Period ◽  
Significant Yield

Research was conducted from 1982 through 1984 on a Shipps clay soil (Udic chromustert) in east-central Texas to determine the density-dependent effects and critical periods of johnsongrass [Sorghum halepense(L.) Pers. # SORHA] competition with cotton (Gossypium hirsutumL.). Two experiments were conducted each year, one to assess cotton yield response to increasing johnsongrass density and the second to establish the johnsongrass-free requirement of cotton and the johnsongrass competition period. A critical minimum density of 2 plants/9.8 m of row was observed. Full-season johnsongrass competition densities exceeding 2 plants/9.8 m of row resulted in seed cotton yield reductions each year. Yield decline was most rapid as density increased from 2 to 8 plants/9.8 m of row. Yield loss averaged 1, 4, 14, 40, 65, and 70% for johnsongrass densities of 1, 2, 4, 8, 16, and 32 plants/9.8 m of row, respectively. Percent yield loss was proportional to yield potential at johnsongrass densities of 4 and 8 plants/9.8 m of row. Three to four weeks of rhizome johnsongrass competition or 6 weeks of seedling johnsongrass competition resulted in significant yield reductions. Maintaining cotton johnsongrass free for 4 weeks did not prevent significant yield reductions.

scholarly journals U-Pb detrital zircon geochronology of the Upper Paleocene to Lower Eocene Wilcox Group, east-central Texas

Geosphere ◽  
2016 ◽  
Vol 12 (5) ◽  
pp. 1517-1531 ◽  
Author(s):  
Preston J. Wahl ◽  
Thomas E. Yancey ◽  
Michael C. Pope ◽  
Brent V. Miller ◽  
Walter B. Ayers
Keyword(s):  
Detrital Zircon ◽  
Zircon Geochronology ◽  
Lower Eocene ◽  
East Central ◽  
Detrital Zircon Geochronology ◽  
Central Texas ◽  
Upper Paleocene
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