bluuebunny/crossref_metadata_2025_split huggingface dataset:
Academic and Clinical Training in Cleft Palate for Speech-Language Pathologists
Authors: Vallino Linda D. , Lass Norman J. , Bunnell H. Timothy , Pannbacker Mary 
Published: July 2008

Objective: The purpose of this study was to obtain information about academic and clinical training of speech-language pathology students in cleft palate (CP). Methods: Representatives of 232 accredited graduate programs in speech-language pathology were invited via e-mail to complete a web-based 32-item questionnaire. Questions focused on the type and nature of courses offered related to CP, availability of clinical practica, and number of hours of clinical experience by students. An item-by-item analysis was conducted and descriptive statistics obtained. Results: A total of 127 (54.7%) of the programs responded. Sixty-seven percent offered coursework exclusively devoted to CP, and for 53% of these it was a required course. For the programs that did not offer an exclusive course on CP, 35% indicated that CP was covered in other courses such as articulation, voice, or anatomy and physiology. Fifty-four percent of the programs offered clinical practica in CP. For these, a median of five students of a median graduate speech-language pathology class of 43 were enrolled in practica involving CP (range  =  0–21), and students spent a median of 2 hours in practica involving CP (range  =  0–100). Conclusions: Cleft palate is a complex disorder to which many students have limited exposure and for which more graduate training is unlikely since the 1993 American Speech-Language-Hearing Association (ASHA) certification changes. As a result, there is a need to look towards alternative methods to enhance the educational and clinical experiences of students and practitioners in cleft palate.
IS THE EFFECT OF FOREST STRUCTURE ON BIRD DIVERSITY MODIFIED BY FOREST PRODUCTIVITY
Authors: Verschuyl Jacob P. , Hansen Andrew J. , McWethy David B. , Sallabanks Rex , Hutto Richard L. 
Published: July 2008

Currently, the most common strategy when managing forests for biodiversity at the landscape scale is to maintain structural complexity within stands and provide a variety of seral stages across landscapes. Advances in ecological theory reveal that biodiversity at continental scales is strongly influenced by available energy (i.e., climate factors relating to heat and light and primary productivity). This paper explores how available energy and forest structural complexity may interact to drive biodiversity at a regional scale.We hypothesized that bird species richness exhibits a hump‐shaped relationship with energy at the regional scale of the northwestern United States. As a result, we hypothesized that the relationship between energy and richness within a landscape is positive in energy‐limited landscapes and flat or decreasing in energy‐rich landscapes. Additionally, we hypothesized that structural complexity explains less of the variation in species richness in energy‐limited environments and more in energy‐rich environments and that the slope of the relationship between structural complexity and richness is greatest in energy‐rich environments.We sampled bird communities and vegetation across seral stages and biophysical settings at each of five landscapes arrayed across a productivity gradient from the Pacific Coast to the Rocky Mountains within the five northwestern states of the contiguous United States. We analyzed the response of richness to structural complexity and energy covariates at each landscape. We found that (1) richness had a hump‐shaped relationship with available energy across the northwestern United States, (2) the landscape‐scale relationships between energy and richness were positive or hump shaped in energy‐limited locations and were flat or negative in energy‐rich locations, (3) forest structural complexity explained more of the variation in bird species richness in energy‐rich landscapes, and (4) the slope of the relationship between forest structural complexity and richness was steepest in energy‐limited locations. In energy‐rich locations, forest managers will likely increase landscape‐scale bird diversity by providing a range of forest structural complexity across all seral stages. In low‐energy environments, bird diversity will likely be maximized by managing local high‐energy hotspots judiciously and adjusting harvest intensities in other locations to compensate for slower regeneration rates.
THE INFLUENCE OF SUCCESSIONAL PROCESSES AND DISTURBANCE ON THE STRUCTURE OFTSUGA CANADENSISFORESTS
Authors: D'Amato Anthony W. , Orwig David A. , Foster David R. 
Published: July 2008

Old‐growth forests are valuable sources of ecological, conservation, and management information, yet these ecosystems have received little study in New England, due in large part to their regional scarcity. To increase our understanding of the structures and processes common in these rare forests, we studied the abundance of downed coarse woody debris (CWD) and snags and live‐tree size‐class distributions in 16 old‐growth hemlock forests in western Massachusetts. Old‐growth stands were compared with eight adjacent second‐growth hemlock forests to gain a better understanding of the structural differences between these two classes of forests resulting from contrasting histories. In addition, we used stand‐level dendroecological reconstructions to investigate the linkages between disturbance history and old‐growth forest structure using an information–theoretic model selection framework.Old‐growth stands exhibit a much higher degree of structural complexity than second‐growth forests. In particular, old‐growth stands had larger overstory trees and greater volumes of downed coarse woody debris (135.2 vs. 33.2 m3/ha) and snags (21.2 vs. 10.7 m3/ha). Second‐growth stands were characterized by either skewed unimodal or reverse‐J shaped diameter distributions, while old‐growth forests contained bell‐shaped, skewed unimodal, rotated sigmoid, and reverse J‐shaped distributions. The variation in structural attributes among old‐growth stands, particularly the abundance of downed CWD, was closely related to disturbance history. In particular, old‐growth stands experiencing moderate levels of canopy disturbance during the last century (1930s and 1980s) had greater accumulations of CWD, highlighting the importance of gap‐scale disturbances in shaping the long‐term development and structural characteristics of old‐growth forests. These findings are important for the development of natural disturbance‐based silvicultural systems that may be used to restore important forest characteristics lacking in New England second‐growth stands by integrating structural legacies of disturbance (e.g., downed CWD) and resultant tree‐size distribution patterns. This silvicultural approach would emulate the often episodic nature of CWD recruitment within old‐growth forests.
Application of statistical experimental design and multivariate data analysis for evaluation of mixtures using cytochrome P4501A induction
Authors: Jensen Maria Helene Steinnes , Krøkje Åse 
Published: July 2008

AbstractCytochrome P4501A (CYP1A) induction was evaluated in the rat hepatoma cell line H4IIE as a biomarker of exposure to organic compounds. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazoliumbromide assay was performed to assess the viability of cells exposed to environmentally relevant concentrations of cadmium. Cadmium concentrations greater than approximately 0.7 μM were found to affect cell viability. Cells were exposed to environmentally relevant concentrations of 3,3′,4,4′-tetrachlorobiphenyl (PCB 77) or benzo[a]pyrene (BaP) and to combinations of PCB 77, BaP, and cadmium based on a statistical experimental design. Quantification of CYP1A proteins using Western blot analysis showed that both BaP and PCB 77 induced CYP1A in a concentration-dependent manner up to 5 μM. Response surface modeling for evaluation of the combined effect of compounds was conducted using the multivariate regression model projection to latent structures (PLS). Analysis of response surface models for the ternary mixtures indicated antagonistic interactions between BaP and PCB 77 and a possible inhibitory effect of cadmium on PCB 77-induced CYP1A. Use of CYP1A induction in the H4IIE cell line with immunodetection of CYP1A proteins, combined with the application of response surface design and PLS, is shown to be a suitable strategy for evaluating combined effects in pollutant mixtures.
Effects of methylmercury and spatial complexity on foraging behavior and foraging efficiency in juvenile white ibises (Eudocimus albus)
Authors: Adams Evan M , Frederick Peter C 
Published: July 2008

Abstract
Methylmercury is a globally distributed neurotoxin, endocrine disruptor, and teratogen, the effects of which on wildlife at environmentally relevant levels are largely unknown. In birds, foraging efficiency and learning may be sensitive endpoints for sublethal methylmercury toxicity, and these endpoints also may be biologically relevant at the population level. In the present study, groups of wild-caught, prefledgling white ibises (Eudocimus albus) were raised in a free-flight, open-air aviary on diets that approximated the measured range of methylmercury exposure in the Everglades ecosystem (0, 0.05, 0.1, and 0.3 mg/kg/d). The effect of methylmercury exposure on group foraging efficiency was examined by allowing birds to forage on 200 fathead minnows (Pimephales promelas) in artificial ponds for 15 min by straining the arenas' contents through a seine net and counting all remaining prey. Additionally, we varied the difficulty of foraging by these tactile feeding birds by adding multiple levels of structural complexity (e.g., increased vegetation and prey refugia) to the pond. Structural complexity affected both foraging efficiency and the rate of increase in efficiency over time (improvement). Methylmercury exposure affected foraging efficiency (p = 0.03). It did not affect foraging improvement in the face of increasingly challenging environments, however, and the dose-response relationship was nonlinear (e.g., the control and high-exposure groups were the least efficient foragers). Evidence for an effect of methylmercury on foraging efficiency therefore was inconclusive because of unpredicted results and no interaction with time or habitat complexity. These data suggest a nonlinear dose-response relationship at low levels of methylmercury exposure; future research is needed to verify this hypothesis. This appears to be the first experimental demonstration of the effects of habitat complexity on foraging efficiency in long-legged wading birds.
Direct and indirect photolysis of polycyclic aromatic hydrocarbons in nitrate-rich surface waters
Authors: Jacobs Laura E , Weavers Linda K , Chin Yu-Ping 
Published: July 2008

Abstract
The photolysis of three polycyclic aromatic hydrocarbons (PAHs)—pyrene, phenanthrene, and naphthalene—were studied in waters taken from creosote-contaminated sites in Gary (IN, USA) and Wilmington (NC, USA). Direct photolysis of all PAHs was observed under simulated solar radiation, with pyrene degrading at a faster rate than either phenanthrene or naphthalene. Phenanthrene degradation, when compared to its direct photolysis rate, increased in Gary water but decreased in Wilmington water. Analysis of the waters for dissolved organic carbon (DOC) and nitrate revealed higher levels of DOC in the Wilmington sample (9.29 mg/L) compared with the Gary sample (6.73 mg/L), as well as significantly less nitrate (0.046 mM vs 0.205 mM for the Gary sample). The slightly lower rate of phenanthrene degradation observed for the Wilmington sample, corrected for light attenuation effects, is statistically the same as that in the direct photolysis experiments. Therefore, we attribute the lower rate of degradation in the presence of Wilmington water to light screening by DOC, but we believe the faster reaction rate observed for the Gary water results from hydroxyl radical (OH•) chemistry generated by nitrate photolysis. Indeed, degradation of the target compound increased when nitrate (at 0.2 and 0.4 mM) was added to the Wilmington sample, further corroborating this conclusion. Overall photoreaction rates decreased for the lower-molecular-weight PAHs, because the fastest naphthalene photolytic rate was roughly two orders of magnitude slower than that of pyrene.
Clutch morphology and the timing of exposure impact the susceptibility of aquatic insect eggs to esfenvalerate
Authors: Palmquist Katherine R , Jenkins Jeffrey J , Jepson Paul C 
Published: July 2008

Abstract
We investigated Baetis spp. (mayfly), Hesperoperla pacifica (stonefly), and Brachycentrus americanus (caddisfly) susceptibility at the egg stage to esfenvalerate, a synthetic pyrethroid insecticide. Eggs were obtained from the field or from field-collected gravid females at sites near Corvallis (OR, USA) and the Metolius River at Camp Sherman (OR, USA) for static exposures under controlled conditions for temperature and light. Eggs were exposed to esfenvalerate for 48 h at concentrations ranging from 0.025 to 4.0 μg/L. No effect on mortality or posthatch growth was detected in H. pacifica eggs exposed to esfenvalerate concentrations up to 1.0 μg/L. Exposure to 0.07 μg/L of esfenvalerate, however, caused a significant increase in Baetis spp. egg mortality, and exposure of near-eclosion eggs to lower concentrations (0.025 and 0.05 μg/L) resulted in behavioral effects and reduced survivorship in newly hatched Baetis nymphs. Early stage B. americanus eggs were 10-fold more sensitive to esfenvalerate when removed from the gelatinous clutch before exposure, an indication that the gelatin affords protection from toxicant exposure. Exposures of near-hatch B. americanus clutches to esfenvalerate concentrations ranging between 0.035 and 0.2 μg/L, however, resulted in significant clutch death within clutches resulting from behavioral aberrations of first-instar larvae. The results of the present study suggest that aquatic insect egg clutch morphology can be a strong influence on susceptibility of embryos to esfenvalerate exposure.
Impact of aquatic insect life stage and emergence strategy on sensitivity to esfenvalerate exposure
Authors: Palmquist Katherine R , Jepson Paul C , Jenkins Jeffrey J 
Published: July 2008

AbstractWe investigated the impact of aquatic insect life stage and emergence strategy on sensitivity to esfenvalerate, a synthetic pyrethroid insecticide, using field-collected Brachycentrus americanus Banks (Trichoptera: Brachycentridae) and Cinygmula reticulata McDunnough (Ephemeroptera: Heptageniidae) insects. Final-instar C. reticulata emergence was observed for one week following three environmentally relevant, 48-h esfenvalerate exposures (0.005, 0.01, and 0.015 μg/L). Emergence was significantly depressed following exposure to esfenvalerate and resulted from an increase in nymph mortality during the emergence process. This experiment was duplicated for late-instar C. reticulata nymphs, which were similar in size to the final-instar nymphs but were not near emergence. Late-instar C. reticulata mayflies were approximately fivefold less sensitive to esfenvalerate exposures as gauged by one-week mortality rates. Brachycentrus americanus pupal mortality was significantly increased over that in controls following 48-h esfenvalerate exposures of 0.1 and 0.2 μg/L. These response concentrations correlated closely with those for case-abandonment rates of fourth-instar B. americanus larvae (a sublethal effect of esfenvalerate exposure). Pupal mortality rates were approximately 16-fold higher than those observed in larvae. Adult female egg weight as a percentage of total body weight was significantly decreased following pupal esfenvalerate exposures of 0.05, 0.1, and 0.2 μg/L. These findings suggest that exposure to esfenvalerate may impair hemimetabolous insect emergence behaviors and may decrease fecundity in holometabolous aquatic insects.
Effects of dietary esfenvalerate exposures on three aquatic insect species representing different functional feeding groups
Authors: Palmquist Katherine R , Jenkins Jeffrey J , Jepson Paul C 
Published: July 2008

Abstract
Given the chemical properties of synthetic pyrethroids, it is probable that compounds, including esfenvalerate, that enter surface waters may become incorporated into aquatic insect food sources. We examined the effect of dietary esfenvalerate uptake in aquatic insects representing different functional feeding groups. We used three field-collected aquatic insect species: A grazing scraper, Cinygmula reticulata McDunnough (Ephemeroptera: Heptageniidae); an omnivorous filter feeder, Brachycentrus americanus Banks (Trichoptera: Brachycentridae); and a predator, Hesperoperla pacifica Banks (Plecoptera: Perlidae). Laboratory-cultured algae were preexposed for 24 h to esfenvalerate concentrations of 0, 0.025, 0.05, and 0.1 μg/L and provided to two C. reticulata age classes (small and final-instar nymphs). Reduction in small nymph growth was observed following three weeks of feeding on algae exposed to 0.05 and 0.1 μg/L of esfenvalerate, and the highest dietary exposure reduced egg production in final-instar nymphs. The diet for B. americanus and H. pacifica consisted of dead third-instar Chironomus tentans larvae preexposed for 24 h to esfenvalerate concentrations ranging between 0.1 and 1.0 μg/L. Consumption of larvae exposed to 0.5 to 1.0 μg/L of esfenvalerate caused case abandonment and mortality in B. americanus caddisfly larvae. Although H. pacifica nymphs readily consumed esfenvalerate-exposed larvae, no adverse effects were observed during the present study. Furthermore, no evidence of esfenvalerate-induced feeding deterrence was found in any of the species tested, suggesting that aquatic insects may not be able to distinguish between pyrethroid-contaminated and uncontaminated food sources. These findings indicate that feeding deterrence is not a factor in regulating aquatic insect dietary exposures to synthetic pyrethroids.
Biogeochemical toxicity and phytotoxicity of nitrogenous compounds in a variety of arctic soils
Authors: Anaka Alison , Wickstrom Mark , Siciliano Steven D 
Published: July 2008

AbstractAmmonium nitrate (NH4NO3) is a common water pollutant associated with many industrial and municipal activities. One solution to reduce exposure of sensitive aquatic systems to nitrogenous compounds is to atomize (atmospherically disperse in fine particles) contaminated water over the Arctic tundra, which will reduce nitrogen loading to surface water. The toxicity of ammonium nitrate to Arctic soils, however, is poorly understood. In the present study, we characterized the biogeochemical toxicity and phytotoxicity of ammonium nitrate solutions in four different Arctic soils and in a temperate soil. Soil was exposed to a range of ammonium nitrate concentrations over a 90-d period. Dose responses of carbon mineralization, nitrification, and phytotoxicity endpoints were estimated. In addition to direct toxicity, the effect of ammonium nitrate on ecosystem resilience was investigated by dosing nitrogen-impacted soils with boric acid. Ammonium nitrate had no effect on carbon mineralization activity and only affected nitrification in one soil, a polar desert soil from Cornwallis Island, Northwest Territories, Canada. In contrast, ammonium nitrate applications (43 mmol N/L soil water) significantly impaired seedling emergence, root length, and shoot length of northern wheatgrass (Elymus lanceolatus). Concentrations of ammonium nitrate in soil water that inhibited plant parameters by 20% varied between 43 and 280 mmol N/L soil water, which corresponds to 2,100 to 15,801 mg/L of ammonium nitrate in the application water. Arctic soils were more resistant to ammonium nitrate toxicity compared with the temperate soil under these study conditions. It is not clear, however, if this represents a general trend for all polar soils, and because nitrogen is an essential macronutrient, nitrogenous toxicity likely should be considered as a special case for soil toxicity.
Global expression profiling of Chlamydomonas reinhardtii exposed to trace levels of free cadmium
Authors: Simon Dana F , Descombes Patrick , Zerges William , Wilkinson Kevin J 
Published: July 2008

Abstract
In the natural environment, cadmium is often found as a trace contaminant. Due to the complexity of Cd speciation and the heterogeneity of natural systems and processes, it is often difficult to determine clear relationships between analytical measurements of Cd and its induced biological response. Measurements of gene induction can be used to identify molecular mechanisms underlying toxicity and to quantify sublethal responses to trace contaminants. In the present paper, genes that could be involved in the tolerance of Cd to green algae were examined using two global transcriptome profiling strategies. Microarray and differential display techniques were used for a global transcriptome analysis of Chlamydomonas reinhardtii exposed to micromolar and lower Cd2+ concentrations for a short period (2 h). Real-time quantitative polymerase chain reaction analysis confirmed that a small set of 10 genes was differentially expressed in response to trace Cd2+ exposures ranging from 7.8 nM to 9.0 μM. Since induction was only observed for a few genes, none of which are known to function in a general stress response, it was likely the result of relevant responses to Cd exposure. The identified genes are discussed with respect to their possible involvement in Cd tolerance and to their future use as biomarkers for monitoring Cd bioavailability in natural soils and waters.
Effect of storage temperature on the activity of submitochondrial particles
Authors: Doherty Francis G 
Published: July 2008

AbstractThe submitochondrial particle (SMP) assay employs processed mammalian mitchondria to assess the toxicity of chemical contaminants in aqueous solutions. Particles and associated reagents are commercially available to support two individual procedures, the electron transfer (ETr) and reverse electron transfer (RET) assays. The objective of the present study was to assess the effect of storage temperature on SMP activity. One RET and one ETr assay were conducted with sodium dodecylsulfate on each of two vials of particles stored at — 20 and — 80°C at periodic intervals over a six-month span. Results demonstrated that SMP could remain active in either assay through six months of storage at either temperature. However, there were isolated vials of particles stored at —20°C that exhibited unacceptable reductions in activity for both the ETr and the RET assays that were not related to storage duration. These results were used to develop guidance in assessing the acceptability of particle activity in SMP assays.
An Investigation of Recent Deconvolution Methods for Well-Test Data Analysis
Authors: Onur M. , Çinar M. , Ilk D. , Valkó P. P. , Blasingame T. A. , Hegeman P. S. 
Published: July 2008

Summary
In this work, we present an investigation of recent deconvolution methods proposed by von Schroeter et al. (2002, 2004), Levitan (2005) and Levitan et al. (2006), and Ilk et al. (2006a, b). These works offer new solution methods to the long-standing deconvolution problem and make deconvolution a viable tool for well-test and production-data analysis. However, there exists no study presenting an independent assessment of all these methods, revealing and discussing specific features associated with the use of each method in a unified manner. The algorithms used in this study for evaluating the von Schroeter et al. and Levitan methods represent our independent implementations of their methods based on the material presented in their papers, not the original algorithms implemented by von Schroeter et al. and Levitan. Three synthetic cases and one field case are considered for the investigation.
Our results identify the key issues regarding the successful and practical application of each method. In addition, we show that with proper care and attention in applying these methods, deconvolution can be an important tool for the analysis and interpretation of variable rate/pressure reservoir performance data.