Agronomic and economic implications of cover crop and phosphorus fertilizer management practices for water quality improvement.

Phosphorus (P) fertilization practices and winter cover crops are promoted to protect water quality yet can potentially influence crop yield and profitability. This study examined the impacts of three P fertilizer management practices (no P, fall broadcast P, and spring injected P) and winter annual cover crop use on yields, net returns, and water quality in a no-till corn-soybean rotation. Treatments were replicated in a 4-yr field study where sediment, total P, and dissolved reactive P (DRP) losses in edge-of-field surface runoff were continuously monitored. Production budgets were developed for each treatment and coupled with water quality data to identify optimal practices and opportunity costs for improving water quality. Applying P fertilizers increased crop yield regardless of application method or cover crop, but the response was more pronounced in corn than soybean. The cover crop reduced corn grain yield in 1 yr with high temperature and low precipitation but did not impact grain yield in the other corn year or either year of soybean. The most profitable treatment was fall broadcast P fertilizer with no cover crop, which also had the greatest total P and DRP losses and near greatest sediment loss. The lowest-cost methods of reducing total P, DRP, and sediment losses were, respectively, no P fertilizer without a cover crop ($47.56 kg-1 total P), spring injected P fertilizer without a cover crop ($56.47 kg-1 DRP), and spring injected P fertilizer with a cover crop ($0.16 kg-1 sediment). Widespread adoption of these practices will likely require monetary incentives.

Cover crop and phosphorus fertilizer management impacts on surface water quality from a no-till corn-soybean rotation.

Best management practices that reduce potential phosphorus (P) loss and provide flexibility in P fertilizer management are needed to help producers protect water quality while maintaining crop yield. This study examined the impacts of P fertilizer management (no P, fall broadcast P, and spring injected P) and cover crop use on annual concentrations and loads of sediment, total P, and dissolved reactive P (DRP) in edge-of-field runoff from a no-till corn (Zea mays)-soybean (Glycine max) rotation in the Central Great Plains, USA, from September 2015 through September 2019. The spring injected P fertilizer treatment generally had 19% less total P and 33% less DRP loss compared to the fall broadcast treatment, confirming the importance of P fertilizer management as a practice for reducing P loss. The addition of a cover crop had an inconsistent effect on total P loss, with no effect in 2016 and 2017, increasing loss in 2018 by 56%, and decreasing it in 2019 by 40%. The inconsistent impact of cover crops on total P loss was related to cover crop effects on sediment loss. Although cover crop impacts on total P losses were inconsistent, the addition of a cover crop increased DRP loss in three of four years. Cover crop use consistently reduced sediment loss, with greater sediment reduction when P fertilizer was applied. Results from this study highlight the benefit of cover crops for reducing sediment loss and the continued need for proper fertilizer management to reduce P loss from agricultural fields.

Species and termination method effects on phosphorus loss from plant tissue.

Cover crops are often recommended as a best management practice to reduce erosion, weed pressure, and nutrient loss. However, cover crops may be sources of phosphorus (P) to runoff water after termination. Two greenhouse trials were conducted to determine the effects of cover crop species, termination method, and time after termination on water-extractable P (WEP) release from crop biomass. Treatments were structured in a 3 × 3 × 3 factorial and arranged in a randomized complete block design with six replicates. Treatments included three cover crop species (triticale [× Triticosecale; Triticum × Secale 'Trical'], rapeseed [Brassica napus L. 'Winfred'], and crimson clover [Trifolium incarnatum L.]); three termination methods (clipping, freezing, and herbicide); and three WEP extraction times (1, 7, and 14 d after termination). Rapeseed consistently resulted in the least WEP when exposed to the same method of termination and at the same extraction time as the other species. For both trials, terminating crop tissue via freezing increased concentrations of WEP compared with other termination methods. The WEP release from cover crop tissue increased as the time after extraction increased, but the effect was greater for herbicide- and freeze-terminated cover crops and less for clipping-terminated cover crops. Future studies on WEP release from cover crops should pay close attention to the effects of extraction timing. Producers may be able to reduce P loss from cover crop tissue by selecting cover crop species with low WEP and minimizing the amount of biomass exposed to freezing conditions.

Gravity Wave Spectra in the Lower Stratosphere Diagnosed from Project Loon Balloon Trajectories.

Project Loon has been launching super-pressure balloons since January 2013 to provide worldwide Internet coverage. These balloons typically fly between 18-21 km and provide measurements of winds and pressure fluctuations in the lower stratosphere. We divide 1,560 Loon flights into 3,405 two-day segments for gravity wave analysis. We derive the kinetic energy spectrum from the horizontal balloon motion and estimate the temperature perturbation spectrum (proportional to the potential energy spectrum) from the pressure variations. We fit the temperature (and kinetic energy) data to the functional form T , 2 = T O , 2 ( ω / ω O ) α where ω is the wave frequency, ω o is daily frequency, T' o is the base temperature amplitude and α is the slope. Both the kinetic energy and temperature spectra show -1.9±0.2 power-law dependence in the intrinsic frequency window 3 - 50 cycles/day. The temperature spectrum slope is weakly anti-correlated with the base temperature amplitude. We also find that the wave base temperature distribution is highly skewed. The average tropical modal temperature is 0.77 K. The highest amplitude waves occur over the mountainous regions, the tropics, and the high southern latitudes. Temperature amplitudes show little height variation over our 18-21 km domain. Our results are consistent with other limited super-pressure balloon analyses. The modal temperature is higher than the temperature currently used in Lagrangian model gravity wave parameterizations.

Practical application of cellular bioenergetics to the care of aged skin.

In human skin fibroblasts in vitro, procollagen-1 and NAD(+)/NADH were reduced in three strains of adult fibroblasts compared with neonatal fibroblasts. The levels of both procollagen-1 and NAD(+)/NADH were increased in the adult fibroblasts by treatment for 24 (NAD energy) or 48 h (procollagen-1) with a complex containing niacinamide, Pal-KTTKS peptide and an olive oil fatty acid derivative (Olivem(®)), especially in combination with a natural extract from dill (Lys'lastine V(®)). In one of the adult fibroblast strains evaluated, these changes in procollagen-1 and NAD(+)/NADH in response to the complex of bioactives were in parallel with increased expression of mRNA biomarkers related primarily to dermal matrix and basement membrane structure, including COL1A1, COL3A1, COL5A1, COL14A1, ELN and LOXL2, in addition to SOD2, NAMPT and TGFBR3; MMP1 was decreased in expression. In general, these mRNA biomarker effects were maintained or boosted by the addition of Lys'lastine V, particularly at 1%, and were similar to the fold changes in mRNA expression in neonatal compared with adult fibroblasts. These results indicate that the complex of niacinamide, Pal-KTTKS and Olivem, especially with addition of Lys'lastine V, increases the NAD(+)/NADH bioenergy level of adult skin fibroblasts in parallel with increased expression of skin structure biomarkers in vitro to levels similar to those in younger fibroblasts. Thus, niacinamide, Pal-KTTKS, Olivem and Lys'lastine V are promising bioactive candidates for inclusion in cosmetic formulations.

SU-E-T-25: Real Time Simulator for Designing Electron Dual Scattering Foil Systems.

PURPOSE: To create a user friendly, accurate, real time computer simulator to facilitate the design of dual foil scattering systems for electron beams on radiotherapy accelerators. The simulator should allow for a relatively quick, initial design that can be refined and verified with subsequent Monte Carlo (MC) calculations and measurements. METHODS: The simulator consists of an analytical algorithm for calculating electron fluence and a graphical user interface (GUI) C++ program. The algorithm predicts electron fluence using Fermi-Eyges multiple Coulomb scattering theory with a refined Moliere formalism for scattering powers. The simulator also estimates central-axis x-ray dose contamination from the dual foil system. Once the geometry of the beamline is specified, the simulator allows the user to continuously vary primary scattering foil material and thickness, secondary scattering foil material and Gaussian shape (thickness and sigma), and beam energy. The beam profile and x-ray contamination are displayed in real time. RESULTS: The simulator was tuned by comparison of off-axis electron fluence profiles with those calculated using EGSnrc MC. Over the energy range 7-20 MeV and using present foils on the Elekta radiotherapy accelerator, the simulator profiles agreed to within 2% of MC profiles from within 20 cm of the central axis. The x-ray contamination predictions matched measured data to within 0.6%. The calculation time was approximately 100 ms using a single processor, which allows for real-time variation of foil parameters using sliding bars. CONCLUSIONS: A real time dual scattering foil system simulator has been developed. The tool has been useful in a project to redesign an electron dual scattering foil system for one of our radiotherapy accelerators. The simulator has also been useful as an instructional tool for our medical physics graduate students.

Investigating reading disabilities using the rauding diagnostic system.

Should a measure of intelligence be replaced by a measure of listening in discrepancy definitions of reading disability? This question was answered using a newly developed diagnostic system, which is based on "rauding" theory and a causal model of reading achievement. In Study 1, diagnostic results were analyzed from 122 students in Grades 3 through 7 who took, via computer, a battery of tests called the computer Assisted Reading Diagnosis (CARD). In Study 2, 44 university students were given the CARD. In Study 3, the CARD was administered to 128 students in reading improvement classes at a suburban community college. From the results, it was concluded that the rauding diagnostic system consistently diagnoses disabilities in listening, decoding, and naming speed when they are theoretically needed to explain accuracy and rate disabilities of children and adults who are poor readers. It was recommended that (a) general intelligence, fluid intelligence, or IQ not be used to measure potential or to diagnose reading disabilities; (b) listening not be used to measure potential; (c) verbal knowledge aptitude, pronunciation aptitude, and cognitive speed aptitude be used to measure potential; and (d) the new rauding diagnostic system replace the system of diagnosing dyslexics, hyperlexics, and garden-variety poor readers.

Effects of methocel A15LV, polyethylene glycol, and polyvinyl alcohol on CD13 and CD33 receptor surface content and metabolism of HL60 cells cultured in stirred tank bioreactors.

Flow cytometry was used to examine the effect of hydrodynamic forces in a stirred tank bioreactor on the CD13 and CD33 receptor surface content of HL60 (human promyelocytic leukemia) cells. A step increase in agitation rate from 80 to 400 rpm reduced the HL60 cell apparent growth rate and increased the CD13 receptor surface content per cell, on average, by 95%. In contrast, this step increase in agitation rate to 400 rpm decreased the CD33 receptor surface content per cell, on average, by 10%. The protective effects of 0.1% Methocel A15LV, polyethylene glycol (PEG), and polyvinyl alcohol (PVA) on CD13 and CD33 receptor surface content were examined under agitation at 300 rpm in parallel 2 L bioreactor runs. The average CD33 receptor surface content was unaffected by the presence of Methocel A15LV or PEG, while PVA had a slight protective effect. In contrast, in terms of CD13 receptor content, HL60 cells agitated at 300 rpm with Methocel A15LV, PEG, or PVA behaved like cells agitated at 80 rpm with no media additives (McDowell and Papoutsakis, 1998). That is, Methocel A15LV, PEG, and PVA prevented the transduction of mechanical forces which affect CD13 cell content. HL60 cells cultured with 0.1% A15LV, PEG or PVA under conditions of mild agitation (60 rpm) in spinner flasks exhibited glucose consumption and lactate production rates that were approximately 20% lower than values of cultures containing no additive. Under conditions of agitation at 300 rpm in the 2 L bioreactor, the presence of A15LV, PEG, and PVA reduced the HL60 glucose consumption and lactate production rates by approximately 50%. Thus, media additives can dramatically reduce lactate accumulation in agitated bioreactors due to cell growth, in addition to providing protection from cellular injury.

Hepatic expression of ErbB3 is repressed by insulin in a pathway sensitive to PI-3 kinase inhibitors.

ErbB3 is an epidermal growth factor receptor-related type I tyrosine kinase receptor capable, in conjunction with ErbB2 or epidermal growth factor receptor, of transmitting proliferative and differentiative signals in a variety of cell types. We previously showed that ErbB3 messenger RNA and protein increase in cultured hepatocytes during the first 12 h in culture, as does the binding of heregulin beta1, a ligand for ErbB3. Insulin inhibits the increase in heregulin beta1 binding, as well as the increase in ErbB3 messenger RNA and protein. Two models of insulin deficiency in vivo (diabetes and fasting) demonstrated elevated levels of hepatic ErbB3 protein, strengthening the relevance of our observations in vitro. Using chemical activators or antagonists, we sought to identify the signaling pathways that link insulin to ErbB3 expression. The PI-3 kinase inhibitors, wortmannin and LY294002, completely blocked the inhibition of ErbB3 protein expression by insulin, suggesting a role for PI-3 kinase in the regulation of this growth factor receptor. Rapamycin, an inhibitor of p70 S6 kinase, an enzyme downstream of PI-3 kinase, failed to block the effect of insulin on ErbB3 expression. These results suggest a complex regulatory paradign for ErbB3 that includes PI-3 kinase and may be linked, via insulin, to the metabolic status of the animal.

Effects of amount of attention allocated to the location of visual stimulus pairs on perception of simultaneity.

This study was examined whether a change in the amount of attention equally allocated to two locations affects judgments of the simultaneity or successiveness of stimuli presented at those locations. Observers were cued to expect two brief flashes either to the left and right of fixation or above and below fixation. Stimulus onset asynchrony was randomly varied. On a small proportion of trials, the stimuli appeared at the unexpected locations. Observers were more likely to report the stimuli as simultaneous when they appeared in the unexpected locations. A model proposed to account for the data assumes that a brief stimulus event is represented by a probability distribution reflecting the uncertainty in determining the time of the event's occurrence, and two events are judged to be simultaneous if they are perceived to fall within some critical temporal interval, c, which is a function of the amount of attention allocated to the task.

Insulin regulates heregulin binding and ErbB3 expression in rat hepatocytes.

The heregulin-ErbB system of ligands and receptors are newly described epidermal growth factor (EGF) and EGF receptor-related proteins that regulate growth, differentiation, and gene expression in numerous cell types. This study describes a receptor for heregulin beta-1 (HRGbeta1) on cultured rat hepatocytes and an inhibitory influence of insulin on HRGbeta1 binding. HRGbeta1 (30 nM) stimulated DNA synthesis 2-fold and was not augmented by insulin as is the case with EGF receptor ligands. A labeled peptide corresponding to the EGF domain of HRGbeta1 bound to a single population of 19,600 +/- 1,800 binding sites/cell with a Kd of 360 +/- 22 pM. Cross-linking experiments showed binding of HRGbeta1 to ErbB3 but not ErbB2 or ErbB4. HRGbeta1 induced phosphorylation of ErbB3 and decreased ErbB3 protein levels, suggesting that HRGbeta1 activates signaling through the ErbB3 receptor and influences receptor trafficking. Following plating, [125I]HRGbeta1 binding and ErbB3 protein levels increased 8- and 3-fold, respectively, over the first 12 h in culture. These increases required de novo protein synthesis and were inhibited with 50 nM insulin resulting in 3500 binding sites with a Kd of 265 pM. These data suggest that the heregulin-ErbB system can regulate liver functions and may be linked to the metabolic and nutritional status of the animal.

Effects of nimodipine and dexamethasone on low-level CO2 laser-induced release of 51chromium from canine 2C5 gliosarcoma cells.

Low-energy penumbral irradiation of surgical lasers may produce undesirable effects on surrounding tissues. This study used a 51Cr cell labeling technique to determine if gliosarcoma cells could be therapeutically protected prior to their exposure to low-power laser irradiation. Canine 2C5 gliosarcoma cells with intracellular 51Cr were treated with nimodipine and/or dexamethasone and then exposed to low-power levels of CO2 laser. The 51Cr was released from the cells in a dose-dependent fashion following exposure to laser energy. Correlative analysis of the data indicated that a strong direct relationship between laser fluence and 51Cr release did exist for controls and drug-treated groups with coefficients of correlation r > or = +0.90 and coefficients of determination r2 > or = 0.82. However, comparison of the data from the drug-treated and control groups found that there was no significant difference between them (P > .05). Therefore, no protective or detrimental effects were observed with the use of nimodipine and/or dexamethasone on the gliosarcoma cells as tested in this system. Further investigation is necessary in order to define the mechanisms by which low-power level lasers affect these cells. These effects do not appear to be mediated through localization of mechanisms to the cell membranes or their constituent Ca2+ channels.

Low-level CO2 laser-induced release of 51chromium from canine 2C5 gliosarcoma cells.

Recently, interest has grown in the area of low-power laser effects upon tissues. We used a 51Cr cell labeling technique with glioma tissue to better understand these effects. Canine 2C5 gliosarcoma cells with intracellular 51Cr were exposed to CO2 laser in the range of 0.2 to 3.0 J/cm2. Correlative analysis of the data indicated that there is a strong direct relationship between laser fluence and the percent of total intracellular 51Cr released from the glioma cells with a coefficient of correlation (r) of +0.93. The calculated standard error of the correlation coefficient was +/- 0.06 and the coefficient of determination (r2) was 0.86. These results indicate that the 51Cr cell labeling technique is a useful method for quantifying the low-power laser effects on the integrity of the cell membrane of gliosarcoma cells in vitro. However, further investigation is needed to clarify the specific mechanisms by which the CO2 laser induces changes upon these cells.

TGF beta 1 and TGF beta 2 are potential growth regulators for low-grade and malignant gliomas in vitro: evidence in support of an autocrine hypothesis.

Low-grade astrocytomas, anaplastic astrocytomas and glioblastomas in vitro were found to ubiquitously produce the mRNA of transforming growth factor-beta (TGF beta). TGF beta 1 and TGF beta 2 mRNA were expressed to a lesser degree among the hyperdiploid malignant gliomas. By radioreceptor assay of conditioned medium, TGF beta was secreted predominantly in latent form, in both latent and active form, or only in active form within a panel of low-grade and malignant gliomas. The TGF beta receptor (types I, II, and III) was evident among the glioma lines. Many near-diploid gliomas were growth-inhibited by TGF beta 1 and TGF beta 2 in vitro. Most hyperdiploid glioblastomas showed a positive mitogenic response to exogenous TGF beta 1 and TGF beta 2. A synergistic or additive mitogenic interaction with epidermal growth factor and insulin was observed among some. Under serum-free conditions, anti-TGF beta antibody neutralized the expected growth-regulatory effect of endogenous TGF beta, thus establishing the specificity of the response in vitro. TGF beta 1 also enhanced the clonogenicity of certain gliomas which had been growth-stimulated in monolayer. Thus, basic elements in support of an autocrine hypothesis have been demonstrated: TGF beta mRNA was expressed among low-grade and malignant gliomas, TGF beta was secreted in latent and/or active form into conditioned media and appeared to serve as an endogenous regulator of glioma proliferation in vitro. The mitogenic response, either positive or negative, correlated with the degree of anaplasia and karyotypic divergence.

Prospective study of concurrent ploidy analysis and routine cytopathology in body cavity fluids.

A total of 390 body cavity fluids were analyzed by both cytopathologic examination and flow cytometric DNA analysis. The two methods gave compatible results in analyses of 304 fluids (78%). In 24 patients, cytopathologic studies found the specimens to contain malignant cells, but the DNA content was diploid. This illustrates an area where flow cytometric studies do not extend tumor detection. In 56 fluids from 48 patients, cytologic methods revealed no malignant cells but flow cytometry distinguished aneuploid cell populations; additional clinical information allowed the identification of malignant tumors in 24 (50%) of these patients. Because flow cytometry was able to detect aneuploidy in cases where conventional cytologic examination could not detect malignant cells, the number of patients with tumors detected was increased by 39% beyond those detected by cytologic methods alone in this series.

What happens to the pylorus after pyloromyotomy?

The rate of return to normal of the pylorus muscle in infantile hypertrophic pyloric stenosis was measured by ultrasound, using a simple pyloric volume calculation and a pyloric muscle index. The muscle hypertrophy took from two to 12 weeks to resolve.

Infantile hypertrophic pyloric stenosis--diagnosis from the pyloric muscle index.

Measurements of pyloric length, diameter and muscle thickness were made from ultrasound images of 39 babies, 21 of whom were subsequently found at operation to have infantile hypertrophic pyloric stenosis. From these measurements, the volume of pyloric muscle in cm3 was estimated for each case and divided by the body weight in kilograms. The resulting pyloric muscle index proved to be a much more reliable guide to the diagnosis of pyloric stenosis than any of the individual measurements or the volume estimation alone.

Measurement of tibial torsion by ultrasound.

A method of measuring tibial torsion with ultrasound, using reference lines on the tibia, was developed and tested on dry adult tibiae. This technique was used for evaluation of a group of children with apparently normal tibiae and another group of children with spina bifida, cerebral palsy, or clubfoot. The study showed that it is possible to measure true tibial torsion (rather than tibiofibular torsion) with ultrasound. The technique was found to be reliable and accurate enough for routine clinical use and had advantages over clinical methods and other radiographic imaging techniques. Values obtained by this technique are higher than those obtained by methods using the bimalleolar axis as the distal reference line.

Soft-tissue changes accompanying recent scaphoid injuries.

In 200 consecutive cases of suspected scaphoid fracture, 27 such fractures were demonstrated. Radiologically, when a fracture was present, the soft tissues on the dorsum of the wrist were definitely abnormal in 24 cases and equivocal in only three cases, whereas the scaphoid fat pad was normal in two cases and equivocal in 13 cases. In addition, in 88 cases when the soft tissues on the dorsum of the wrist were definitely normal, no fracture was ever demonstrated.