Daniel B. Stephens and Associates , Inc.

Albuquerque, NM, United States

Daniel B. Stephens and Associates , Inc.

Albuquerque, NM, United States

Time filter

Source Type

Leyden J.,Skin Study Center | Stephens T.J.,Daniel B. Stephens and Associates , Inc.
Journal of the American Academy of Dermatology | Year: 2012

Background: Until now, nonablative fractional treatments could only be delivered in an office setting by trained professionals. Objective: The goal of this work was to perform clinical testing of a nonablative fractional laser device designed for home-use. Methods: This multicenter trial consisted of two clinical studies with slightly varying treatment protocols in which subjects performed at-home treatments of periorbital wrinkles using a handheld nonablative fractional laser. Both studies included an active treatment phase (daily treatments) and a maintenance phase (twice-weekly treatments). In all, 36 subjects were followed up for as long as 5 months after completion of the maintenance phase and 90 subjects were followed up until the completion of the maintenance phase. Evaluations included in-person investigator assessment, independent blinded review of high-resolution images using the Fitzpatrick Wrinkle Scale, and subject self-assessment. Results: All 124 subjects who completed the study were able to use the device following written instructions for use. Treatments were well tolerated with good protocol compliance. Independent blinded evaluations by a panel of physicians showed Fitzpatrick Wrinkle Scale score improvement by one or more grades in 90% of subjects at the completion of the active phase and in 79% of subjects at the completion of the maintenance phase. The most prevalent side effect was transient posttreatment erythema. Limitations: Lack of a control group and single-blinded study groups were limitations. Conclusion: Safety testing with self-applications by users demonstrated the utility of the device for home use. Independent blinded review of clinical images confirmed the device's proficiency for improving periorbital wrinkles. © 2012 by the American Academy of Dermatology, Inc.


Hutter C.M.,Fred Hutchinson Cancer Research Center | Hutter C.M.,University of Washington | Chang-Claude J.,German Cancer Research Center | Slattery M.L.,University of Utah | And 53 more authors.
Cancer Research | Year: 2012

Genome-wide association studies (GWAS) have identified more than a dozen loci associated with colorectal cancer (CRC) risk. Here, we examined potential effect-modification between single-nucleotide polymorphisms (SNP) at 10 of these loci and probable or established environmental risk factors for CRC in 7,016 CRC cases and 9,723 controls from nine cohort and case - control studies. We used meta-analysis of an efficient empirical-Bayes estimator to detect potential multiplicative interactions between each of the SNPs [rs16892766 at 8q23.3 (EIF3H/UTP23), rs6983267 at 8q24 (MYC), rs10795668 at 10p14 (FLJ3802842), rs3802842 at 11q23 (LOC120376), rs4444235 at 14q22.2 (BMP4), rs4779584 at 15q13 (GREM1), rs9929218 at 16q22.1 (CDH1), rs4939827 at 18q21 (SMAD7), rs10411210 at 19q13.1 (RHPN2), and rs961253 at 20p12.3 (BMP2)] and select major CRC risk factors (sex, body mass index, height, smoking status, aspirin/nonsteroidal antiinflammatory drug use, alcohol use, and dietary intake of calcium, folate, red meat, processed meat, vegetables, fruit, and fiber). The strongest statistical evidence for a gene - environment interaction across studies was for vegetable consumption and rs16892766, located on chromosome 8q23.3, near the EIF3H and UTP23 genes (nominal P interaction = 1.3 × 10 -4; adjusted P = 0.02). The magnitude of the main effect of the SNP increased with increasing levels of vegetable consumption. No other interactions were statistically significant after adjusting for multiple comparisons. Overall, the association of most CRC susceptibility loci identified in initial GWAS seems to be invariant to the other risk factors considered; however, our results suggest potential modification of the rs16892766 effect by vegetable consumption. ©2012 AACR.


Pease R.E.,Daniel B. Stephens and Associates , Inc. | Stormont J.C.,University of New Mexico | Hines J.,Daniel B. Stephens and Associates , Inc. | O'Dowd D.,Daniel B. Stephens and Associates , Inc.
Geotechnical Testing Journal | Year: 2010

This paper presents the laboratory results and methods used to measure the hydraulic parameters of asphalt concrete core samples. The same testing methods used to measure the saturated hydraulic conductivity and moisture retention in soils were applied to the asphalt concrete cores. Moisture retention was analyzed according to the van Genuchten (1980) mathematical model to produce the drying portion of the moisture retention curves. In addition to standard desorption tests, wetting curves were developed for two asphalt concrete cores. Saturated hydraulic conductivity was measured using a flexible wall permeameter. The asphalt concrete differs from these soils by maintaining a much lower porosity, and the dry asphalt concrete exhibited a water repellant behavior. Copyright © 2010 by ASTM.


Mahan S.,U.S. Geological Survey | Kay J.,Daniel B. Stephens and Associates , Inc.
Quaternary Geochronology | Year: 2012

The long term stability and reliability of the luminescence signal for gypsum has not been well documented or systematically measured until just recently. A review of the current literature for luminescence dating of gypsum is compiled here along with original efforts at dating an intact and in-situ bed of selenite gypsum at Salt Basin Playa, New Mexico and Texas. This effort differs from other documented luminescence dating efforts because the gypsum is not powdery or redistributed from its original growth patterns within the playa basin but is instead of a crystalline form. Sixteen ages from eight cores were ultimately produced with seven of the ages coming from rare detrital quartz encased in or with the gypsum crystals while the remaining ages are from the crystalline gypsum. As far as can be ascertained, the quartz was measured separately from the gypsum and no contaminants were noted in any of the aliquots. Some basic and preliminary tests of signal stability were measured and found to be mitigated by lessening of pre-heat protocols. Ages ranged from 8 ka to 10 ka in the shallow cores and 16 ka to 22 ka in the deeper cores. These ages will be useful in determining rates of gypsum growth within a sequence of evaporates which, in turn, will help to better document historic rates of evaporation and thus estimate, with more precision, the corresponding annual evaporation rates. © 2012 .


Schnaar G.,Daniel B. Stephens and Associates , Inc. | Brusseau M.L.,University of Arizona
Journal of Environmental Science and Health - Part A Toxic/Hazardous Substances and Environmental Engineering | Year: 2013

The miscible-displacement method is one commonly used approach for measuring equilibrium sorption coefficients. The objective of this research was to examine the impact of experiment conditions (detection limit, input-pulse size, input concentration) on the measurement of retardation factors and sorption coefficients for a system that exhibits significant nonideal sorption behavior. A series of miscible-displacement experiments was conducted wherein effluent solute concentrations were monitored over a range of approximately seven orders of magnitude, allowing characterization of asymptotic tailing phenomenon, which was significant. The magnitude of Kd increased asymptotically with the increase in the extent of the elution tail measured. The results also showed that the fraction of the tail required to obtain close-to-maximum measures of Kd is greater for smaller input pulses. Investigating the impact of analytical detection limit (equivalent to relative concentrations of 10-3 and 10-7) revealed that the magnitude of Kd was invariant with input pulse for the 10 -7 detection limit. Conversely, the measured Kd values were significantly smaller at low input pulses for the 10-3 detection limit. © 2013 Copyright Taylor and Francis Group, LLC.


Stephens D.B.,Daniel B. Stephens and Associates , Inc.
Groundwater | Year: 2015

The U.S. Environmental Protection Agency (EPA) was contacted by citizens of Pavillion, Wyoming 6years ago regarding taste and odor in their water wells in an area where hydraulic fracturing operations were occurring. EPA conducted a field investigation, including drilling two deep monitor wells, and concluded in a draft report that constituents associated with hydraulic fracturing had impacted the drinking water aquifer. Following extensive media coverage, pressure from state and other federal agencies, and extensive technical criticism from industry, EPA stated the draft report would not undergo peer review, that it would not rely on the conclusions, and that it had relinquished its lead role in the investigation to the State of Wyoming for further investigation without resolving the source of the taste and odor problem. Review of the events leading up to EPA's decision suggests that much of the criticism could have been avoided through improved preproject planning with clear objectives. Such planning would have identified the high national significance and potential implications of the proposed work. Expanded stakeholder involvement and technical input could have eliminated some of the difficulties that plagued the investigation. However, collecting baseline groundwater quality data prior to initiating hydraulic fracturing likely would have been an effective way to evaluate potential impacts. The Pavillion groundwater investigation provides an excellent opportunity for improving field methods, report transparency, clarity of communication, and the peer review process in future investigations of the impacts of hydraulic fracturing on groundwater. © 2014, National Ground Water Association.


Brusseau M.L.,University of Arizona | Russo A.E.,University of Arizona | Schnaar G.,University of Arizona | Schnaar G.,Daniel B. Stephens and Associates , Inc.
Chemosphere | Year: 2012

A series of miscible-displacement experiments was conducted to examine the impact of sorption contact time on desorption and elution of trichloroethene from a well-characterized soil. A large number of contact times were examined, spanning 1h to 4years (∼2×106h). Effluent trichloroethene concentrations were monitored over a range of greater than six orders of magnitude, allowing characterization of potential asymptotic tailing. The results of the column experiments showed that trichloroethene exhibited extensive elution tailing for all experiments. Each increase in contact time resulted in a successive increase in the extent of tailing. In total, the number of pore volumes of water flushing required to reach the analytical detection limit increased from approximately 1000 for the 1-h contact time to almost 9000 for the 4-year contact time. These results indicate that a contact time of less than 1h produced a sorbed phase that is relatively resistant to desorption, and that a progressive increase in resistance to desorption occurred with increased contact time. A mathematical model incorporating nonlinear, rate-limited sorption/desorption described by a continuous-distribution reaction function was used to successfully simulate the measured data. The nonlinear sorption, the apparent rapid development of desorption resistance, and the progressive increase in resistance with increasing contact time are consistent with behavior anticipated for sorbate interactions with hard-carbon components of the soil. © 2012 Elsevier Ltd.


Simco A.H.,Daniel B. Stephens and Associates , Inc. | Stephens D.B.,Daniel B. Stephens and Associates , Inc. | Calhoun K.,Daniel B. Stephens and Associates , Inc. | Stephens D.A.,Daniel B. Stephens and Associates , Inc.
Vadose Zone Journal | Year: 2010

During the agricultural revolution, land drainage in England transformed landscapes from wetlands to productive fields and pastures. Two of Great Britain's most famous land drainers, Joseph Elkington and William Smith, 200 years ago separately undertook then pioneering work to improve the land of the Duke of Bedford at Priestley Farm. Based on historical maps, archival information, and aerial photographs, as well as discussions with the current property owner and field reconnaissance of geologic and cultural features, we have identified the exact locations of two drained fields sketched by William Smith in his 1806 publication. The fields are significant in the agricultural history of England because experimental irrigation and drainage conducted there was undertaken, perhaps for the first time, to demonstrate agricultural advances for the national benefit. © Soil Science Society of America.


Stephens D.B.,Daniel B. Stephens and Associates , Inc. | Miller M.,Daniel B. Stephens and Associates , Inc. | Moore S.J.,Daniel B. Stephens and Associates , Inc. | Umstot T.,Daniel B. Stephens and Associates , Inc. | Salvato D.J.,Daniel B. Stephens and Associates , Inc.
Journal of the American Water Resources Association | Year: 2012

Stormwater capture for groundwater recharge in urban areas is usually conducted at the regional level by water agencies. Field and modeling studies in New Mexico indicate that stormwater diverted to retention basins may recharge about 50% of precipitation that falls on the developed area, even in dry climates. Comparable volumes of recharge may be expected at homes, subdivisions, or commercial properties with low-impact development (LID) technologies for stormwater control that promote recharge over evapotranspiration. Groundwater quality has not been significantly impacted at sites that have been recharging stormwater to aquifers for decades. Distributed recharge systems may be a good alternative to centralized regional facilities where there is limited land for constructing spreading basins or little funding for new infrastructure. LID technologies borrowed from stormwater managers are important tools for groundwater managers to consider to enhance recharge. © 2011 American Water Resources Association.


PubMed | Daniel B. Stephens and Associates , Inc.
Type: Journal Article | Journal: Ground water | Year: 2015

The U.S. Environmental Protection Agency (EPA) was contacted by citizens of Pavillion, Wyoming 6years ago regarding taste and odor in their water wells in an area where hydraulic fracturing operations were occurring. EPA conducted a field investigation, including drilling two deep monitor wells, and concluded in a draft report that constituents associated with hydraulic fracturing had impacted the drinking water aquifer. Following extensive media coverage, pressure from state and other federal agencies, and extensive technical criticism from industry, EPA stated the draft report would not undergo peer review, that it would not rely on the conclusions, and that it had relinquished its lead role in the investigation to the State of Wyoming for further investigation without resolving the source of the taste and odor problem. Review of the events leading up to EPAs decision suggests that much of the criticism could have been avoided through improved preproject planning with clear objectives. Such planning would have identified the high national significance and potential implications of the proposed work. Expanded stakeholder involvement and technical input could have eliminated some of the difficulties that plagued the investigation. However, collecting baseline groundwater quality data prior to initiating hydraulic fracturing likely would have been an effective way to evaluate potential impacts. The Pavillion groundwater investigation provides an excellent opportunity for improving field methods, report transparency, clarity of communication, and the peer review process in future investigations of the impacts of hydraulic fracturing on groundwater.

Loading Daniel B. Stephens and Associates , Inc. collaborators
Loading Daniel B. Stephens and Associates , Inc. collaborators