Northwest Texas Research Articles

PREY USE AND PROVISIONING RATES OF BREEDING FERRUGINOUS AND SWAINSON'S HAWKS ON THE SOUTHERN GREAT PLAINS, USA

Abstract We collected diet data at 12 Ferruginous Hawk (Buteo regalis) and 14 Swainson's Hawk (B. swainsoni) nests in a short-grass prairie and agricultural community in the panhandle area of northwest Texas and southwest Oklahoma, and in northeastern New Mexico during the 2003–2004 breeding seasons. We documented 959 Ferruginous Hawk and 1,058 Swainson's Hawk prey deliveries during ∼5,618 hrs of video monitoring. Ferruginous Hawks delivered 10.0 ± 0.7 (x ± SE) prey species per nest and typically larger prey. Swainson's Hawks delivered 13.4 ± 1.1 prey species per nest and typically smaller prey. There was a dietary overlap (Simplified Morisita Index [CH]) of 0.31 in prey species delivery frequency and 0.56 in prey species' biomass. Ferruginous Hawks made 4.6 deliveries/day at 480 g/delivery whereas Swainson's Hawks delivered smaller prey items (147 g/delivery) but more frequently (7.0 deliveries/day). Deliveries/day and mass/day increased with increasing brood sizes of both species, but deliveries/day/ne...

First Financial Bankshares, Inc.

AbstractCommercial Banking (MIC: 8.1 SIC: 6022 NAIC: 522110)First Financial Bankshares is a financial holding company that owns, through its wholly‐owned subsidiary, all of the capital stock of 10 banks located in Texas. Through its subsidiary, Co. conducts a full‐service commercial banking business, with service centers located primarily in North Central and West Texas. Each subsidiary bank's main source of revenue is providing loans and banking services to consumers and commercial customers in the market area in which it is located. Co. also owns First Financial Trust & Asset Management Company, National Association and First Technology Services, Inc., an information technology subsidiary. As of Dec 31 2006, Co. had total assets of $2.85 billion.

First Financial Bankshares, Inc.

AbstractCommercial Banking (MIC: 8.1 SIC: 6022 NAIC: 522110)First Financial Bankshares is a financial holding company that owns, through its wholly‐owned subsidiary, all of the capital stock of 10 banks located in Texas. Through its subsidiary, Co. conducts a full‐service commercial banking business, with service centers located primarily in North Central and West Texas. Each subsidiary bank's main source of revenue is providing loans and banking services to consumers and commercial customers in the market area in which it is located. Co. also owns First Financial Trust & Asset Management Company, National Association and First Technology Services, Inc., an information technology subsidiary. As of Dec 31 2006, Co. had total assets of $2.85 billion.

First Financial Bankshares, Inc.

AbstractCommercial Banking (MIC: 8.1 SIC: 6022 NAIC: 522110)First Financial Bankshares is a financial holding company that owns, through its wholly‐owned subsidiary, all of the capital stock of 10 banks located in Texas. Through its subsidiary, Co. conducts a full‐service commercial banking business, with service centers located primarily in North Central and West Texas. Each subsidiary bank's main source of revenue is providing loans and banking services to consumers and commercial customers in the market area in which it is located. Co. also owns First Financial Trust & Asset Management Company, National Association and First Technology Services, Inc., an information technology subsidiary. At Dec 31 2006, Co. had total assets of $2.85 billion.

Deep Time and the Texas High Plains: History and Geology (review)

Reviewed by: Deep Time and the Texas High Plains: History and Geology Brian Frehner Deep Time and the Texas High Plains: History and Geology. By Paul H. Carlson. (Lubbock: Texas Tech University Press, 2005. Pp. 160. Preface, illustrations, charts, tables, maps, notes, select bibliography, index. ISBN 0896725529. $34.95, cloth. ISBN 0896725537. $19.95, paper.) Paul H. Carlson tackles an admirable but daunting task—explaining in only 117 pages how geological forces shaped history over the course of more than ten thousand years at an archaeological site and its surrounding region on the Texas High Plains. Drawing upon John McPhee's concept of "deep time," the author proposes to capture the "long geological past" of the Lubbock Lake archaeological site located in northwest Texas's Llano Estacado region (p. xv). At times, the vast scale and scope of change Carlson describes overwhelms the narrative and prevents him from focusing sufficiently on the Lubbock Lake site or even the Llano Estacado. Carlson sets a context of "deep time" by starting with the Big Bang approximately ten to fifteen billion years ago. He briefly surveys the evolution of stars, the Earth's internal structure, and the geologic time scale. "Then, over deep time, the great Pangaea separated" (p. 6). As geological processes formed different rocks, dinosaurs appeared and became extinct and mammals evolved. By the end of chapter one, the author has surveyed the prehistoric past up to approximately ten thousand years ago. The scope and impact of the change Carlson covers is so all-encompassing and global in its reach that the reader is left to wonder whether the author has provided too much context. Paleoindian cultures provide the subject matter for the next chapter, and here too the author struggles to strike a balance between generalizations about pre-Clovis, Clovis, and Folsom cultures and more specific assertions about choices people made accommodating their lives to the Lubbock Lake and Llano Estacado environments. Although archaeologists have uncovered extensive evidence of these cultures throughout North America, it is never entirely clear what lessons Paleoindians' lives illuminate for the modern reader about this particular environment which, after all, purports to serve as the book's focal point. Carlson does a better job of characterizing the impacts of long-term climate and environmental change on the Llano Estacado's people and land in chapter three, [End Page 417] which focuses on the Archaic period (8,500 to 2,000 years ago). Due to a semi-arid interval of time, animals dependent on the region's water supplies departed as vegetative cover gradually decreased at the Lubbock Lake site. People continued to use the site, though, to camp and gather plants. Carlson is on shakier ground when he characterizes social organization during the Archaic period. For example, he states that sharing, egalitarianism, and flexible social institutions "must have been present" and acknowledges that he can only "speculate" about mobility patterns (p. 65). The next two chapters cover the period from two thousand years ago to the present. Carlson discusses rather informatively and adroitly the process by which Indian people branched off into separate cultural groupings, contested one another for access to the area, and felt the impact of Europeans entering the area. He then narrates Americans' attempts to hunt bison and ranch the area, their impacts on the local environment, and archaeological activity that has uncovered much of the information that makes up this study. Historians should produce more studies of the kind Carlson has tackled. Geology significantly shapes history by defining the limits of the stage upon which environmental, biological, and human events unfold. The relationships between geology and history are manifold and complex, and Carlson unflinchingly sets out to articulate how the two intersect. This approach presents the Herculean task of identifying how the grand sweep of geological time unfolded in smaller regions and local environments in ways readers can comprehend. Brian Frehner Oklahoma State University Copyright © 2007 The Texas State Historical Association

Swift Fox Use of Black-Tailed Prairie Dog Towns in Northwest Texas

Biologists have suggested that prairie dog (Cynomys ludovicianus) towns provide important habitat for several prairie species including swift foxes (Vulpes velox). To examine this issue for swift foxes, we radiocollared and monitored 72 swift foxes in areas occupied by prairie dogs on the Rita Blanca National Grasslands and on fragmented private ranches in northwest Texas from January 2002 to April 2004. We overlaid swift fox locations on vegetation maps and found that swift foxes used prairie dogs towns proportionately less than expected (P < 0.001) in 5 of 6 comparisons based upon availability at both study sites. In one comparison swift foxes used prairie dog towns as expected. We also mapped swift fox den locations and found that den sites were located in prairie dog towns (2 of 106 den sites on national grasslands and 2 of 87 on private ranch for all years pooled) as expected based upon availability (P = 0.54 and P = 0.34). Previous research in these areas of Texas indicated that prairie dogs were a minor component of swift fox diet (<2%). Prairie dog towns do not appear to provide important habitat for swift foxes in northwest Texas or other similar sites because prairie dogs are not a significant source of food for swift foxes, because swift foxes generally avoid prairie dog towns during their normal activities, and because swift foxes only den in prairie dog towns in relation to their availability.

Effects of Artificial Escape Dens on Swift Fox Populations in Northwest Texas

Throughout the range of swift fox (Vulpes velox), coyotes (Canis latrans) are the primary source of swift fox mortality. Coyotes may suppress swift fox populations where densities are high. Because coyote numbers have increased since wolves (Canis lupus) have been exterminated, we hypothesized that escape habitats may limit swift foxes. To test our hypothesis, we installed artificial escape dens in 3 spatially separated (treated) areas on the Rita Blanca National Grasslands in Dallam County, Texas, USA. From January 2002 to August 2004, we captured, radiocollared, and monitored 55 swift foxes. Annual swift fox survival in artificial escape-den—treated areas (Ŝ = 0.81) was higher than in untreated areas (Ŝ = 0.52, P = 0.07). Relative swift fox abundance was higher in treated than untreated areas in 2002 (Yates' χ2 = 4.61, P = 0.03) and in 2003 (Yates' χ2 = 4.70, P = 0.03) but not in 2004 (Yates' χ2 = 2.67, P = 0.10). However, recruitment rates were no different between treated and untreated areas in 2002 (Yates' χ2 = 0.21, P = 0.65) or 2003 (Yates' χ2 = 0.41, P = 0.52). Ninety-five percent fixed-kernel estimates of home-range sizes revealed no difference (P = 0.91) between treated and untreated areas, but swift foxes increased their distribution by moving into an area that had been unoccupied for at least 3 years before this study. Our results suggest that artificial escape dens contributed to increasing swift fox distributions in our study area.

Widespread Presence of Naturally Occurring Perchlorate in High Plains of Texas and New Mexico

Perchlorate (CLO4-) occurrence in groundwater has previously been linked to industrial releases and the historic use of Chilean nitrate fertilizers. However, recently a number of occurrences have been identified for which there is no obvious anthropogenic source. Groundwater from an area of 155,000 km2 in 56 counties in northwest Texas and eastern New Mexico is impacted bythe presence of ClO4-. Concentrations were generally low (<4 ppb), although some areas are impacted by concentrations up to 200 ppb. ClO4- distribution is not related to well type (public water system, domestic, agricultural, or water-table monitoring) or aquifer (Ogallala, Edward Trinity High Plains, Edwards Trinity Plateau, Seymour, or Cenozoic). Results from vertically nested wells strongly indicate a surface source. The source of ClO4- appears to most likely be atmospheric deposition. Evidence supporting this hypothesis primarily relates to the presence of ClO4- in tritium-free older water, the lack of relation between land use and concentration distribution, the inability of potential anthropogenic sources to account for the estimated mass of ClO4-, and the positive relationship between conserved anions (e.g., IO3-, Cl-, SO4(-2)) and ClO4-. The ClO4- distribution appears to be mainly related to evaporative concentration and unsaturated transport. This process has led to higher ClO4- and other ion concentrations in groundwater where the water table is relatively shallow, and in areas with lower saturated thickness. Irrigation may have accelerated this process in some areas by increasing the transport of accumulated salts and by increasing the number of evaporative cycles. Results from this study highlight the potential for ClO4- to impact groundwater in arid and semi-arid areas through long-term atmospheric deposition.

CHARACTERISTICS OF SWIFT FOX DENS IN NORTHWEST TEXAS

Abstract The swift fox (Vulpes velox) was classified in 1995 as a candidate for listing under the Endangered Species Act. Since then, several studies have addressed survey methods for monitoring swift fox populations. The purpose of this paper is to assist field researchers in documenting the presence of swift foxes by identification of recently active den sites. We propose that swift foxes have unique external den characteristics that can be distinguished during aerial surveys. We collected data from 30 swift fox den complexes on both continuous rangeland and landscapes fragmented by cropland in northwest Texas. There were no differences in den characteristics between landscape types (P > 0.10). The number of openings per den ranged from 1 to 8 and had an average opening height of 20 cm. As number of openings increased, the maximum distance between openings also increased (r = 0.88, P < 0.001). One of the most distinguishing characteristics of swift fox dens was their dirt tailing. Of 74 den openings exa...

Insect biostratigraphy of the Euramerican continental Late Pennsylvanian and Early Permian

Abstract An insect zonation with a time resolution of 1.5–2 Ma for Late Pennsylvanian to Early Permian (Kasimovian to Artinskian) non-marine deposits is presented. The zonation is based on the directed morphogenetic evolution of colour pattern in the forewings of the blattid (cockroach) family Spiloblattinidae. This evolution is observed in lineages of succeeding species of three genera. All three genera are widely distributed in the palaeo-equatorial zone from Europe to North America, that is, in the Euramerican biota province. Increasing reports of spiloblattinid zone species in condont-bearing, interfingered marine/continental strata of North American Appalachian, Mid-Continent and West Texas basins could be the key to direct biostratigraphical correlations of pure continental profiles, as are present in the most parts of the Hercynides, to the global marine scale.

Swift Fox, &lt;em&gt;Vulpes velox&lt;/em&gt;, Den Located Next to a Railroad Track in Northwestern Texas

Swift Fox (Vulpes velox) dens are typically found in areas were the vegetation is sparse, in loam soils, and with unobstructed views of the surrounding area. In 2002 a Swift Fox in northwest Texas was found in a unique den situated at the base of a hill with the entrance within 1 m of an active railroad track. Use of a den in such proximity to railroad tracks has never been previously reported.

Soil-geomorphic relations of lamellae in eolian sand on the High Plains of Texas and New Mexico

Clay lamellae are ubiquitous features in sands in a wide variety of settings around the world. Most studies of lamellae focus on: 1) a few or individual locales or on 2) formation by experimental methods in the laboratory. This study reports on lamellae from eight localities in three late-Quaternary dune fields on the Southern High Plains of northwest Texas and eastern New Mexico. Most lamellae observed are illuvial and they increase in number and thickness through time. A few (1–3) thin (1–2 mm) lamellae formed in Historic sediments. Lamellae are more numerous (3–12) and thicker (3–5 mm) in older late Holocene (< 1000 14C years BP) and middle Holocene (< 7600 14C years BP) sands. Soils that formed through the late Pleistocene and into the early Holocene (14,300–7600 14C years BP) or soils that formed throughout the Holocene can exhibit as many as 30 lamellae or lamellae of 10–12 mm thickness. The micromorphology of the lamellae shows that argillans on sand grains are thicker, more laminated, more continuous, and cap and link more grains through time. Other variables affect lamella morphology. Within individual dunes, the lamellae are best expressed where the sand is thickest; they decrease in number and thickness as sand thins. The lamellae also form only in clean, well-drained sand. Poor drainage and/or bioturbation result in formation of a continuous argillic horizon encasing lamellae.

Systemic manifestations in response to mydriasis and physical examination during screening for retinopathy of prematurity

Infant's distress during funduscopic examination has been demonstrated in previous studies. The aim of this study was to determine whether adverse effects manifested via vital sign changes during the screening examination for retinopathy of prematurity (ROP) are because of the pharmacologic properties of the eye drops or to physical manipulation of the eyes. The authors also investigated the relationship between distress during the screening process and the severity of prematurity of the infant. In a prospective observational study, all infants (n = 30) either weighing ≤1500 g or who were ≤32 weeks gestational age at birth and were admitted to the neonatal intensive care unit (NICU) at Northwest Texas Hospital or Baptist St. Anthony's Hospital from June 2002 to February 2003 were enrolled. Blood pressure, pulse, temperature, respiratory rate, and oxygen saturation were recorded at different time intervals during the examination. Infants were excluded from the study if they were on the ventilator, considered acutely ill, born with significant birth defects, or currently taking inotropic drugs, or had received albuterol two hours before the examination. The authors found that oxygen saturation and pulse rate following physical manipulation of the eyes significantly varied from baseline values and the values obtained during the three instillations of topical mydriatics. No significant changes in blood pressure, temperature, or respiratory rate from their respective baseline values were observed throughout the ROP screening examination. Gestational age of the infant did not correlate with level of distress during the examination. The authors conclude that regardless of the severity of prematurity, infants seem to undergo significant distress during the eyelid speculum examination. Thus ophthalmologists should take into consideration the infant's discomfort caused by physical manipulation of the eyes and attempt to perform the examination as quickly and as safely as possible using topical anesthetic.—Valerie Biousse

Radioactivity in the Ogallala and Dockum Aquifers, northwest Texas, USA

This study investigated distributions of alpha and beta activity in the Ogallala and Dockum Aquifers of northwest Texas, USA. The survey included 319 samples from the Ogallala Aquifer and 48 samples from the Dockum Aquifer. The Ogallala Aquifer produced slightly higher median alpha (7.2 versus 6.1 pCi/L) and beta (7.7 versus 7.0 pCi/L) levels. However, a higher percentage of samples from the Dockum Aquifer exceeded drinking water standards, and the maximum alpha observation from that aquifer was 197 pCi/L, more than 13 times the 15-pCi/L standard. Approximately 4.4% of alpha observations from the Ogallala Aquifer and 16.7% of observations from the Dockum Aquifer exceeded the standard. Fewer observations, 0% from the Ogallala Aquifer and 6.3% from the Dockum Aquifer, exceeded the 50-pCi/L level of concern for beta activity. There were significant positive correlations between alpha and beta activity in each aquifer. However, there were no significant correlations between radioactivity and well depth, other than a weak inverse correlation between beta activity and well depth in the Ogallala Aquifer. Uranium deposits in sandstone and shale of the Dockum Aquifer, and in calcrete and silcrete of the Ogallala Aquifer, and overlying lacustrine sediments, likely influence radioactivity patterns observed in this study.

Systemic manifestations in response to mydriasis and physical examination during screening for retinopathy of prematurity.

To determine whether adverse effects manifested via vital sign changes during the screening examination for retinopathy of prematurity (ROP) are due to the pharmacologic properties of the eye drops or to physical manipulation of the eyes. The authors also investigated the relationship between distress during the screening process and the severity of prematurity of the infant. A prospective observational study was designed that enrolled all infants either weighing < or =1500 g or who were < or =32 weeks gestational age at birth who were admitted to the neonatal intensive care unit (NICU) at Northwest Texas Hospital or Baptist St. Anthony's Hospital from June 2002 to February 2003. Thirty participants were enrolled in this study. Blood pressure, pulse, temperature, respiratory rate, and O2 saturation were recorded at different time intervals during the examination. Infants were excluded from the study if they were on the ventilator, considered acutely ill, born with significant birth defects, or currently taking inotropic drugs, or had received albuterol 2 hours before the examination. Oxygen saturation and pulse rate following physical manipulation of the eyes significantly varied from baseline values and the values obtained during the three instillations of topical mydriatics. No significant changes in blood pressure, temperature, or respiratory rate from their respective baseline values were observed throughout the ROP screening examination. Gestational age of the infant did not correlate with level of distress during the examination. Regardless of the severity of prematurity, infants seem to undergo significant distress during the eyelid speculum examination. Thus ophthalmologists should take into consideration the infant's discomfort caused by physical manipulation of the eyes and attempt to perform the examination as swiftly, yet safely, as possible using topical anesthetic.

Study on the fungal aeroallergen concentration in the Texas Panhandle using a Burkard Volumetric Spore Trap

Rationale This investigation was aimed at analyzing the relationship between the meteorological conditions, diurnal variations and the fungal aeroallergen data of the North West Texas Panhandle and to find the correlation between the aeroallergen index and frequency of allergic rhinitis recorded in the allergy clinic. Methods Daily mold spore count was determined by analyzing the Melinex tape from the Burkard Volumetric Spore Trap. Samples were analyzed in every 24 hours and mold spore concentration per cubic meter was determined. The data were correlated with maximum and minimum temperature, daily precipitation and peak wind speed. The daily clinical data were collected from the Allergy A.R.T.S. and were correlated with the daily fungal aeroallergen index. Results The most frequent fungal aeroallergens present during Sept. 2002 to Sept. 2003 were fungal spores like Alternaria, ascospores from Pezizales, Dreschlera, Cladosporium, and Curvularia. Mold spore count had an inverse relationship with the daily temperature. Alternaria conidia were the most abundant component of the dry air spora. We found an association between Alternaria concentration and the cases of severe asthma. Fungal spore concentrations did show more susceptibility to meteorological conditions on a daily basis than did pollen concentrations. Ascomycetes concentrations significantly increased in the hours just following a rain shower. Conclusions We found a very significant correlation between the mold spore concentration and the humidity. A little rain increased the spore count significantly. There was a positive correlation between the number of patients' visits with the increase spore index.

Doppler Radar Observations of Dust Devils in Texas

Abstract Analyses of a dust-devil dataset collected in northwest Texas are presented. The data were collected just above the ground at close range with a mobile, W-band (3-mm wavelength) Doppler radar having an azimuthal (radial) resolution of 3–5 m (30 m) at the range of the dust devils. Most dust devils appeared as quasi-circular rings of relatively high radar reflectivity. Four dust-devil vortices were probed, three of which were cyclonic and one anticyclonic. Documentation was obtained of a pair of adjacent cyclonic vortices rotating cyclonically around each other. Approximate radial profiles of azimuthal and radial wind components and of radar reflectivity are detailed and discussed. The diameters of the core of the dust devils ranged from 30 to 130 m; the latter diameters are much wider than that of typical dust devils in a homogeneous environment. The widest vortex was cyclonic and exhibited evidence of a two-cell structure (i.e., sinking motion near the center and rising motion just outside the ra...

Discussion of Associations Between Rural Land Uses and Ground Water Quality in the Ogallala Aquifer, Northwest Texas by Paul F. Hudak (2002), Ground Water Monitoring &amp; Remediation, v. 22, no. 4, pages 117–120

Discussion of Associations Between Rural Land Uses and Ground Water Quality in the Ogallala Aquifer, Northwest Texas by Paul F. Hudak (2002), <i>Ground Water Monitoring</i> &amp; <i>Remediation</i>, v. 22, no. 4, pages 117–120

Associations Between Rural Land Uses and Ground Water Quality in the Ogallala Aquifer, Northwest Texas

AbstractRecent nitrate, chloride, and bromide concentrations were studied in the Ogallala Aquifer of northwest Texas. The study included 361 wells with a median depth of 92 m in a rural area dominated by agricultural activity and oil and gas production. Only five observations surpassed the 44.3 mg/L standard for nitrate (10 mg/L NO3‐N). Four other observations, and one from the preceding set, exceeded the secondary standard of 250 mg/L for chloride. Maximum concentrations were 91.2 mg/L, 1530 mg/L, and 0.70 mg/L for nitrate, chloride, and bromide, respectively. Chloride/bromide ratios covered a broad range, from 30.4 to 10930, but medians were &lt; 160 for each of two years analyzed. There were statistically significant correlations between nitrate and chloride, and chloride and well depth. Results of this study suggest that agricultural activity has locally impacted ground water in north‐west Texas. Regionally, low aquifer recharge rates have curtailed ground water contamination from potentially adverse land uses.

Cotton yield and applied water relationships under drip irrigation

Different irrigation scheduling methods and amounts of water ranging from deficit to excessive amounts were used in cotton ( Gossypium hirsutum L.) irrigation studies from 1988 to 1999, at Lubbock, TX. Irrigation scheduling treatments based on canopy temperature ( T c) were emphasized in each year. Surface drip irrigation and recommended production practices for the area were used. The objective was to use the 12-year database to estimate the effect of irrigation and growing season temperature on cotton yield. Yields in the irrigation studies were then compared with those for the northwest Texas production region. An irrigation input of 58 cm or total water application of 74 cm was estimated to produce maximum lint yield. Sources of the total water supply for the maximum yielding treatments for each year averaged 74% from irrigation and 26% from rain. Lint yield response to irrigation up to the point of maximum yield was approximated as 11.4 kg ha −1 cm −1 of irrigation between the limits of 5 and 54 cm with lint yields ranging from 855 to 1630 kg ha −1. The intra-year maximum lint yield treatments were not limited by water input, and their inter-year range of 300 kg ha −1 was not correlated with the quantity of irrigation. The maximum lint yields were linearly related to monthly and seasonal heat units (HU) with significant regressions for July ( P=0.15), August ( P=0.07), and from May to September ( P=0.01). The fluctuation of maximum yearly lint yields and the response to HU in the irrigation studies were similar to the average yields in the surrounding production region. The rate of lint yield increase with HU was slightly higher in the irrigation studies than in the surrounding production area and was attributed to minimal water stress. Managing irrigation based on real-time measurements of T c produced maximum cotton yields without applying excessive irrigation.