Showing papers by "University of Arkansas published in 2000"
TL;DR: In this paper, the authors developed and tested a theoretical extension of the TAM model that explains perceived usefulness and usage intentions in terms of social influence and cognitive instrumental processes, which was tested using longitudinal data collected regarding four different systems at four organizations (N = 156), two involving voluntary usage and two involving mandatory usage.
Abstract: The present research develops and tests a theoretical extension of the Technology Acceptance Model (TAM) that explains perceived usefulness and usage intentions in terms of social influence and cognitive instrumental processes. The extended model, referred to as TAM2, was tested using longitudinal data collected regarding four different systems at four organizations ( N = 156), two involving voluntary usage and two involving mandatory usage. Model constructs were measured at three points in time at each organization: preimplementation, one month postimplementation, and three months postimplementation. The extended model was strongly supported for all four organizations at all three points of measurement, accounting for 40%--60% of the variance in usefulness perceptions and 34%--52% of the variance in usage intentions. Both social influence processes (subjective norm, voluntariness, and image) and cognitive instrumental processes (job relevance, output quality, result demonstrability, and perceived ease of use) significantly influenced user acceptance. These findings advance theory and contribute to the foundation for future research aimed at improving our understanding of user adoption behavior.
16,513 citations
TL;DR: Control of the growth kinetics of the II–VI semiconductor cadmium selenide can be used to vary the shapes of the resulting particles from a nearly spherical morphology to a rod-like one, with aspect ratios as large as ten to one.
Abstract: Nanometre-size inorganic dots, tubes and wires exhibit a wide range of electrical and optical properties1,2 that depend sensitively on both size and shape3,4, and are of both fundamental and technological interest In contrast to the syntheses of zero-dimensional systems, existing preparations of one-dimensional systems often yield networks of tubes or rods which are difficult to separate5,6,7,8,9,10,11,12 And, in the case of optically active II–VI and III–V semiconductors, the resulting rod diameters are too large to exhibit quantum confinement effects6,8,9,10 Thus, except for some metal nanocrystals13, there are no methods of preparation that yield soluble and monodisperse particles that are quantum-confined in two of their dimensions For semiconductors, a benchmark preparation is the growth of nearly spherical II–VI and III–V nanocrystals by injection of precursor molecules into a hot surfactant14,15 Here we demonstrate that control of the growth kinetics of the II–VI semiconductor cadmium selenide can be used to vary the shapes of the resulting particles from a nearly spherical morphology to a rod-like one, with aspect ratios as large as ten to one This method should be useful, not only for testing theories of quantum confinement, but also for obtaining particles with spectroscopic properties that could prove advantageous in biological labelling experiments16,17 and as chromophores in light-emitting diodes18,19
4,288 citations
TL;DR: This work proposes a rice developmental staging system divided into three main phases of development: seedling, vegetative, and reproductive, and assigns rice growth stages based on discrete morphological criteria to result in unambiguous growth-stage determination.
Abstract: The large area of rice (Oryza sativa L) production worldwide is critical to the well being of large numbers of the world's people Yet for rice, the most important single plant species for human nutrition, there is not a widely used growth staging system Despite good points of the published rice growth staging systems, none has been used widely for describing rice growth and development Consequently, an objective growth staging system with enumeration adapted to cumulative leaf number (CLN) would improve communication among scientists, farmers, and educators We propose a rice developmental staging system divided into three main phases of development: seedling, vegetative, and reproductive Seedling development consists of four growth stages: unimbibed seed (S0), radicle and coleoptile emergence from the seed (S1,S2), and prophyll emergence from the coleoptile (S3) Vegetative development consists of stages V1, V2 VN; N being equal to the final number of leaves with collars on the main stem Reproductive development consists of 10 growth stages based on discrete morphological criteria: panicle initiation (R0), panicle differentiation (R1), flag leaf collar formation (R2), panicle exertion (R3), anthesis (R4), grain length and width expansion (R5), grain depth expansion (R6), grain dry down (R7), single grain maturity (R8), and complete panicle maturity (R9) Assigning rice growth stages based on discrete morphological criteria will result in unambiguous growth-stage determination For example, using this system, two people staging the same plant will arrive at the same growth stage This is because the system exploits the presence or absence of distinct morphological criteria in a symbolic logic dichotomous framework that only permits yes or no answers
725 citations
TL;DR: In vitro models demonstrated that increasing levels of flavonoids in combination with constant levels of caffeic and ascorbic acid gave a resultant AOX that was either additive of the two compounds or competitive in their ability to scavenge peroxyl radicals.
Abstract: The effect of fruit maturation on changes in carotenoids, flavonoids, total soluble reducing equivalents, phenolic acids, ascorbic acid, and antioxidant activity (AOX) in different pepper types (Capsicum annuum, Capsicum frutescens, and Capsicum chinese) was determined. Generally, the concentration of these chemical constituents increased as the peppers reached maturity. Peppers contained high levels of L-ascorbic acid and carotenoids at maturity, contributing 124-338% of the RDA for vitamin C and 0.33-336 RE/100 g of provitamin A activity, respectively. Levels of phenolic acids, capxanthin, and zeaxanthin generally increased during maturation, whereas the level of lutein declined. Flavonoid concentrations varied greatly among the pepper types analyzed and were negatively correlated to AOX under the conditions of the beta-carotene-linoleic assay. Model systems were used to aid in understanding the relationship between flavonoids and AOX. Significant increases in AOX were observed in pepper juice models in response to increasing dilution factors and the presence of EDTA, indicating a pro-oxidant effect due to metal ions in the system. In vitro models demonstrated that increasing levels of flavonoids in combination with constant levels of caffeic and ascorbic acid gave a resultant AOX that was either additive of the two compounds or competitive in their ability to scavenge peroxyl radicals. The model systems were in good agreement with the chemical composition of the pepper cultivars and reflected the interactions affecting AOX. More research is needed to understand the complex interactions that occur among various antioxidants present in pepper extracts.
617 citations
TL;DR: In this article, the impact of various top management team characteristics on firm international diversification was investigated using data from 126 firms in the electronics industry, and it was shown that higher average age, higher average tenure and higher average elite education are associated with international expansion.
603 citations
TL;DR: A simple method based on alkaline extraction followed by acid precipitation was developed to produce pure silica xerogels from rice hull ash (RHA), with minimal mineral contaminants as discussed by the authors.
562 citations
TL;DR: In this article, the virtual crystal approximation (VCA) was used to predict dielectric and piezoelectric properties of the perovskite solid solution in its paraelectric or ferroelectric phases.
Abstract: We present an approach to the implementation of the virtual crystal approximation (VCA) for the study of properties of solid solutions in the context of density-functional methods. Our approach can easily be applied to any type of pseudopotential, and also has the advantage that it can be used to obtain estimates of the atomic forces that would arise if the real atoms were present, thus giving insight into the expected displacements in the real alloy. We have applied this VCA technique within the Vanderbilt ultrasoft-pseudopotential scheme to predict dielectric and piezoelectric properties of the $\mathrm{Pb}({\mathrm{Zr}}_{0.5}{\mathrm{Ti}}_{0.5}){\mathrm{O}}_{3}$ solid solution in its paraelectric and ferroelectric phases, respectively. Comparison with calculations performed on ordered alloy supercells and with data on parents compounds demonstrates the adequacy of using the VCA for this perovskite solid solution. In particular, the VCA approach reproduces the anomalous Born effective charges and the large value of the piezoelectric coefficients.
560 citations
TL;DR: Agrobacterium-mediated transient expression is a simple and efficient method for in vivo assays of plant promoters and transcription factors and the cis-regulatory regions in these promoters that are responsive to salicylic acid treatment or tobacco mosaic virus infection are identified.
Abstract: A convenient, Agrobacterium-mediated transient expression assay has been evaluated for rapid analysis of plant promoters and transcription factors in vivo. By simple infiltration of Agrobacterium cells carrying appropriate plasmid constructs into tobacco leaves in planta, reproducible expression assays could be conducted in as little as 2-3 days without using expensive equipment (e.g. biolistic gun or electroporation apparatus) or complicated procedures (e.g. preparation of protoplasts). Biotic and abiotic treatments could be applied to the intact plant to examine their influence on promoter activity and gene expression. Using this method, we have tested the stress-responsive as-1 and heat shock elements, yeast GAL4 transactivation system, two promoters of pathogenesis-related (PR) genes as well as a heat shock promoter. Through deletion analyses of tobacco PR1a promoter and a novel myb1 promoter, we have also successfully identified the cis-regulatory regions in these promoters that are responsive to salicylic acid treatment or tobacco mosaic virus infection. Together, our results demonstrate that Agrobacterium-mediated transient expression is a simple and efficient method for in vivo assays of plant promoters and transcription factors.
547 citations
TL;DR: In this paper, a diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS) method was developed to measure the degree of esterification (DE) of commercial pectin samples.
539 citations
TL;DR: In this double-blind study to compare safety of 2 lipid formulations of amphotericin B, neutropenic patients with unresolved fever after 3 days of antibacterial therapy were randomized to receive ABLC or L Amph, and infusional reactions were less frequent with ABLC, but chills/rigors were still higher.
Abstract: In this double-blind study to compare safety of 2 lipid formulations of amphotericin B, neutropenic patients with unresolved fever after 3 days of antibacterial therapy were randomized (1:1:1) to receive amphotericin B lipid complex (ABLC) at a dose of 5 mg/kg/d (n=78), liposomal amphotericin B (L Amph) at a dose of 3 mg/kg/d (n=85), or L Amph at a dose of 5 mg/kg/d (n=81). L Amph (3 mg/kg/d and 5 mg/kg/d) had lower rates of fever (23.5% and 19.8% vs. 57.7% on day 1; P<.001), chills/rigors (18.8% and 23.5% vs. 79.5% on day 1; P<.001), nephrotoxicity (14.1% and 14.8% vs. 42.3%; P<.01), and toxicity-related discontinuations of therapy (12.9% and 12.3% vs. 32.1%; P=.004). After day 1, infusional reactions were less frequent with ABLC, but chills/rigors were still higher (21.0% and 24.3% vs. 50.7%; P<.001). Therapeutic success was similar in all 3 groups.
489 citations
TL;DR: A low-temperature monoclinic phase is confirmed to exist, and is demonstrated to act as a bridge between the well-known tetragonal and rhombohedral phases delimiting the morphotropic phase boundary (MPB).
Abstract: A first-principles-derived approach is developed to study finite-temperature properties of Pb(Zr1-xTix)O3 (PZT) solid solutions near the morphotropic phase boundary (MPB). Structural and piezoelectric predictions are in excellent agreement with experimental data and direct first-principles results. A low-temperature monoclinic phase is confirmed to exist, and is demonstrated to act as a bridge between the well-known tetragonal and rhombohedral phases delimiting the MPB. A successful explanation for the large piezoelectricity found in PZT ceramics is also provided.
TL;DR: A comprehensive contingency-based framework for examining the content related issues involving the relationships and variables included in past studies is presented and several important research design/methodology issues are examined.
TL;DR: The validity of the DSM-IV Global Assessment of Functioning Scale as a scale of global psychopathology; the Social and Occupational Functioning Assessment Scale asA measure of problems in social, occupational, and interpersonal functioning; and the Global assessment of Relational Functioned Scale as an index of personality pathology are supported.
Abstract: OBJECTIVE: The authors investigated the reliability and convergent and discriminant validity of the DSM-IV Global Assessment of Functioning Scale and two experimental DSM-IV axis V global rating scales, the Global Assessment of Relational Functioning Scale and the Social and Occupational Functioning Assessment Scale. METHOD: Forty-four patients admitted to a university-based outpatient community clinic were rated by trained clinicians on the three DSM-IV axis V scales. Patients also completed self-report measures of DSM-IV symptoms as well as measures of relational, social, and occupational functioning. RESULTS: The Global Assessment of Functioning Scale, Global Assessment of Relational Functioning Scale, and Social and Occupational Functioning Assessment Scale all exhibited very high levels of interrater reliability. Factor analysis revealed that the Global Assessment of Relational Functioning Scale and the Social and Occupational Functioning Assessment Scale are each more related to the Global Assessmen...
TL;DR: Delayed disclosure of childhood rape was very common, and long delays were typical, which suggests that the likelihood of disclosure in a given case is difficult to estimate, and predictions based on single variables are unwarranted.
TL;DR: It is reported the first rigorous, experimental evidence demonstrating that undamaged plants respond to cues released by neighbors to induce higher levels of resistance against herbivores in nature.
Abstract: The possibility of communication between plants was proposed nearly 20 years ago, although previous demonstrations have suffered from methodological problems and have not been widely accepted. Here we report the first rigorous, experimental evidence demonstrating that undamaged plants respond to cues released by neighbors to induce higher levels of resistance against herbivores in nature. Sagebrush plants that were clipped in the field released a pulse of an epimer of methyl jasmonate that has been shown to be a volatile signal capable of inducing resistance in wild tobacco. Wild tobacco plants with clipped sagebrush neighbors had increased levels of the putative defensive oxidative enzyme, polyphenol oxidase, relative to control tobacco plants with unclipped sagebrush neighbors. Tobacco plants near clipped sagebrush experienced greatly reduced levels of leaf damage by grasshoppers and cutworms during three field seasons compared to unclipped controls. This result was not caused by an altered light regime experienced by tobacco near clipped neighbors. Barriers to soil contact between tobacco and sagebrush did not reduce the difference in leaf damage although barriers that blocked air contact negated the effect.
TL;DR: How different factors can compromise bone strength by reducing growth, altering shape, affecting mineralization, and affecting collagen crosslinking is discussed.
TL;DR: Treatment is clearly beneficial and cost-effective for patients with progressive forms of histoplasmosis, such as chronic pulmonary or disseminated infection, and it remains unknown whether treatment improves the outcome for patientswith the self-limited manifestations.
Abstract: Objective The objective of this guideline is to provide recommendations for treating patients with the more common forms of histoplasmosis. PARTICIPANTS AND CONSENSUS PROCESS: A working group of 8 experts in this field was convened to develop this guideline. The working group developed and refined the guideline through a series of conference calls. Outcomes The goal of treatment is to eradicate the infection when possible, although chronic suppression may be adequate for patients with AIDS and other serious immunosuppressive disorders. Other important outcomes are resolution of clinical abnormalities and prevention of relapse. Evidence The published literature on the management of histoplasmosis was reviewed. Controlled trials have been conducted that address the treatment of chronic pulmonary and disseminated histoplasmosis, but clinical experience and descriptive studies provide the basis for recommendations for other forms of histoplasmosis. VALUE: Value was assigned on the basis of the strength of the evidence supporting treatment recommendations, with the highest value assigned to controlled trials, according to conventions established for developing practice guidelines. BENEFITS AND COSTS: Certain forms of histoplasmosis cause life-threatening illnesses and result in considerable morbidity, whereas other manifestations cause no symptoms or minor self-limited illnesses. The nonprogressive forms of histoplasmosis, however, may reduce functional capacity, affecting work capacity and quality of life for several months. Treatment is clearly beneficial and cost-effective for patients with progressive forms of histoplasmosis, such as chronic pulmonary or disseminated infection. It remains unknown whether treatment improves the outcome for patients with the self-limited manifestations, since this patient population has not been studied. Other chronic progressive forms of histoplasmosis are not responsive to pharmacologic treatment. Treatment options Options for therapy for histoplasmosis include ketoconazole, itraconazole, fluconazole, amphotericin B (Fungizone; Bristol-Meyer Squibb, Princeton, NJ), liposomal amphotericin B (AmBisome; Fujisawa, Deerfield, IL), amphotericin B colloidal suspension (ABCD, or Amphotec; Seques, Menlo Park, CA), and amphotericin B lipid complex (ABLC, or Abelcet; Liposome, Princeton, NJ).
TL;DR: The two most severe, sustained droughts in the continental United States during the 20th century occurred in the 1930s and 1950s, according to tree-ring reconstructions of the Palmer drought severity index (PDSI) as discussed by the authors.
Abstract: The two most severe, sustained droughts in the continental United States during the 20th century occurred in the 1930s and 1950s. The 1950s drought was most extreme over the southwest and southern Great Plains, where ecological consequences are still evident on the landscape [Swetnam and Betancourt], 1998].The Dust Bowl,vividly recounted in John Steinbeck's The Grapes of Wrath, was the nations most severe, sustained,and widespread drought of the past 300 years, according to tree-ring reconstructions of the Palmer drought severity index (PDSI) across the continental United States [Cook et al., 1999] (http://www.ngdc.noaa.gov/paleo/pdsiyear.html.
Droughts during the 1750s, 1820s, and 1850s–1860s estimated from tree rings were similar to the 1950s drought in terms of magnitude, persistence, and spatial coverage, but these earlier episodes do not appear to have surpassed the severity or extent of the Dust Bowl drought. However, longer tree-ring reconstructions of PDSI for the United States and precipitation for northwestern Mexico and western Canada indicate that the “megadrought” of the 16th century far exceeded any drought of the 20th century (Figure 1) [also see Wood-house and Overpeck, 1998], and is considered to be the most severe prolonged drought over much of North America for at least the last 500 years [Meko et al., 1995].
TL;DR: A review of the comparative psychotherapy process literature can be found in this article, where the authors delineate techniques and processes that distinguish psychodynamic-interpersonal therapy from cognitive-behavioral treatment.
Abstract: The present article is a review of the comparative psychotherapy process literature. It is an effort to delineate techniques and processes that distinguish two prominent forms of treatment. Seven interventions stood out as distinguishing psychodynamic-interpersonal therapy from cognitive-behavioral treatment: (1) a focus on affect and the expression of patients’ emotions; (2) an exploration of patients’ attempts to avoid topics or engage in activities that hinder the progress of therapy; (3) the identification of patterns in patients’ actions, thoughts, feelings, experiences, and relationships; (4) an emphasis on past experiences; (5) a focus on a patients’ interpersonal experiences; (6) an emphasis on the therapeutic relationship; and (7) an exploration of patients’ wishes, dreams, or fantasies. A better understanding of the specific techniques and processes that distinguish psychodynamic-interpersonal from cognitive-behavioral therapy can facilitate process-outcome research, aid in the training and teaching of psychodynamic-interpersonal psychotherapy, and provide psychodynamic-interpersonal therapists with a guide for session activity.
TL;DR: In the crystallographic structure of the V66E mutant, a chain of water molecules was seen that hydrates the buried Glu-66 and links it with bulk solvent, providing compelling and unprecedented experimental evidence that solvent penetration can contribute significantly to the high apparent polarizability inside proteins.
TL;DR: A review of the research conducted on intimacy within the area of social psychology and a summary of the empirical findings related to intimacy functioning in CSA survivors is suggested in this article, with a focus on the theoretical models that appear to have implications for the long-term interpersonal sequelae associated with CSA.
TL;DR: The identification of Oxa1p in mitochondria, an inner membrane translocase component homologous to predicted proteins in bacteria and to the albino3 (ALB3) protein in thylakoids, led us to investigate the potential role of ALB3 in LHCP integration, and data support a model whereby a distinct translocases containing AlB3 is used to integrate LHCP into thylAKoid membranes.
TL;DR: Findings provide considerable insight into the apparently contradictory results reported for trade-offs between pathogen and herbivore resistance.
TL;DR: Progress is being made in the understanding of the pathogenesis of diabetic renal disease and in the ability to delay, or even prevent, this devastating complication, according to this issue of PNAS.
Abstract: Renal failure is a common and serious complication of longstanding diabetes mellitus. Diabetes is now the most common cause of end-stage renal failure requiring dialysis in the United States, accounting for almost 40% of all new dialysis patients (1). Moreover, the incidence of renal failure caused by diabetes, particularly type II diabetes, is rising dramatically worldwide (2). Compounding the tragedy of the explosive growth in the incidence renal failure caused by diabetes is the grim reality that the survival of patients with renal failure caused by diabetes is much worse than that of patients with renal failure resulting from other causes. In Germany, for example, Koch et al. (3) reported a 5-year survival of only 5% among patients with type II diabetes undergoing dialysis. Fortunately, progress is being made in our understanding of the pathogenesis of diabetic renal disease and in our ability to delay, or even prevent, this devastating complication. Two studies appearing in this issue of PNAS (4, 5) are illustrative of this progress. Diabetic nephropathy refers to a characteristic set of structural and functional kidney abnormalities that occur in patients with diabetes. Although best described in patients with type I diabetes (6), similar findings are now known to occur in the more common type II diabetic patient (7). Structural abnormalities include hypertrophy of the kidney, an increase in the thickness of glomerular basement membranes, accumulation of extracellular matrix components in the glomerulus (nodular and diffuse glomerulosclerosis), tubular atrophy, and interstitial fibrosis (6, 7). Functional alterations include an early increase in the glomerular filtration rate with intraglomerular hypertension, subsequent proteinuria, systemic hypertension, and eventual loss of renal function (8).
TL;DR: The regulation of Ang II receptors (AT1R and AT2R) by ox-LDL and the role of the redox-sensitive transcription factor NF-&kgr;B in this process provide a basis for the use of antioxidants and AT1R blockers in designing therapy of atherosclerosis.
Abstract: Background—We demonstrated earlier that angiotensin II (Ang II), by AT1 receptor activation, upregulates oxidized LDL (ox-LDL) endothelial receptor LOX-1 gene expression and uptake of ox-LDL in human coronary artery endothelial cells (HCAECs). In this study, we investigated the regulation of Ang II receptors (AT1R and AT2R) by ox-LDL and the role of the redox-sensitive transcription factor NF-κB in this process. Methods and Results—HCAECs were incubated with ox-LDL for 24 hours. Ox-LDL (10 to 40 μg protein/mL) upregulated AT1R but not AT2R, mRNA, or protein. Ox-LDL degraded IκBα in cytoplasm and activated transcription factor NF-κB (P65) in HCAEC nuclear extract. Treatment of cells with the antioxidant α-tocopherol (10 to 50 μmol/L) attenuated ox-LDL–mediated degradation of IκBα and activation of NF-κB (P65) and inhibited the upregulation of AT1R mRNA and protein. The role of NF-κB signal transduction was further examined by use of an NF-κB inhibitor, caffeic acid phenethyl ester (CAPE). Pretreatment of c...
TL;DR: Comparisons of canopy coverage values with LI measured near solar noon indicated that there was a one-to-one relationship and digital imagery, coupled with appropriate software, offers a simple and effective method of determining canopy coverage and LI.
Abstract: Canopy light interception (LI) is important for yield and crop growth, but LI is often not measured because measurements must be made close to solar noon in unobstructed, direct-beam sunlight. Digital imagery may allow measurements of canopy coverage that are independent of solar radiation and solar angle restrictions. The objectives of this research were to determine the proportion of ground area covered by a soybean (Glycine max L. [Merr.]) canopy from digital images taken from above, and to compare the canopy-coverage measurements with LI measurements. Software limited the scanned areas of digital images to leaves, which allowed calculation of fractional canopy coverage. Similar values of canopy coverage were obtained throughout the day using digital imagery. Furthermore, comparisons of canopy coverage values with LI measured near solar noon indicated that there was a one-to-one relationship. Digital imagery, coupled with appropriate software, offers a simple and effective method of determining canopy coverage and LI.
TL;DR: Hypothesis tests and a models-comparison test using structural equation modeling indicate that the indirect model has a significantly better fit to the data than does the direct model.
Abstract: Two models are developed on the effects of a control system that include participative standard setting, standard-based incentives, and standard tightness. The direct model proposes that the control system directly affects performance, whereas the indirect model proposes that the effects of the control system on performance are indirect through the mediating influence of job-related stress. Hypothesis tests and a models-comparison test using structural equation modeling indicate that the indirect model has a significantly better fit to the data than does the direct model.
TL;DR: It is found that herbivores also promoted nitrification among diverse grasslands, and process-level evidence for N retention by grazers was supported by soil δ15N data.
Abstract: We studied how ungulates and a large variation in site conditions influenced grassland nitrogen (N) dynamics in Yellowstone National Park. In contrast to most grassland N studies that have examined one or two soil N processes, we investigated four rates, net N mineralization, nitrification, denitrification, and inorganic N leaching, at seven paired sites inside and outside long-term (33+ year) exclosures. Our focus was how N fluxes were related to one another among highly variable grasslands and how grazers influenced those relationships. In addition, we examined variation in soil δ15N among grasslands and the relationships between soil 15N abundance and N processes. Previously, ungulates were reported to facilitate net N mineralization across variable Yellowstone grasslands and denitrification at mesic sites. In this study, we found that herbivores also promoted nitrification among diverse grasslands. Furthermore, net N mineralization, nitrification, and denitrification (kg N ha–1 year–1, each variable) were postively and linearly related to one another among all grasslands (grazed and fenced), and grazers reduced the nitrification/net N mineralization and denitrification/net N mineralization ratios, indicating that ungulates inhibited the proportion of available NH4+ that was nitrified and denitrified. There was no relationship between net N mineralization or nitrification with leaching (indexed by inorganic N adsorbed to resin buried at the bottom of rooting zones) and leaching was unaffected by grazers. Soil δ15N was positively and linearly related to in situ net N mineralization and nitrification in ungrazed grasslands; however, there was no relationship between isotopic composition of N and those rates among grazed grasslands. The results suggested that grazers simultaneously increased N availability (stimulated net N mineralization and nitrification per unit area) and N conservation (reduced N loss from the soil per unit net N mineralization) in Yellowstone grasslands. Grazers promoted N retention by stimulating microbial productivity, probably caused by herbivores promoting labile soil C. Process-level evidence for N retention by grazers was supported by soil δ15N data. Grazed grassland with high rates of N cycling had substantially lower soil δ15N relative to values expected for ungrazed grassland with comparable net N mineralization and nitrification rates. These soil 15N results suggest that ungulates inhibited N loss at those sites. Such documented evidence for consumer control of N availability to plants, microbial productivity, and N retention in Yellowstone Park is further testimony for the widespread regulation of grassland processes by large herbivores.
TL;DR: It is argued that EMDR provides an excellent vehicle for illustrating the differences between scientific and pseudoscientific therapeutic techniques and is of critical importance for clinical psychologists who intend to base their practice on the best available research.
TL;DR: Fecal P output could be reduced while maintaining optimum performance by the use of reduced dietary nonphytate P, introduction of HAPC, and phytase supplementation, and one of the greatest benefits of phyt enzyme supplementation appeared to be maintaining livability at lower dietary levels of nonphyTate P.