The Effects of N-Serve on the Availability of Urea and Ureaformaldehyde Nitrogen on Lolium perenne L.

Laboratory experiments were conducted to determine the effect of N-Serve (DOW) on the availability of urea nitrogen and the subsequent greening effect on perennial ryegrass (Lolium perenne L.) seedlings as compared to the availability of nitrogen and subsequent greening from a controlled release ureaformaldehyde fertilizer. A low organic matter sandy loam soil and a high organic matter clay loam soil were used in this study. Soil treatments of urea and ureaformaldehyde fertilizers were applied and incorporated at concentrations of 0, 25, 38, and 50 ppm-N. N-Serve at concentrations of 0.25, 0.50, and 1.0 ppm active ingredient were applied and incorporated with the three highest urea concentrations in all possible combinations. Two hundred grams of soil were placed in styrofoam cups. For each soil, there were six trials corresponding to incubation periods of 0, 2, 3, 4, 5, and 6 weeks. All treatments were replicated three times per each trial. Soil water was maintained at field capacity (by weight) throughout the experiment. All cups were incubated in a room which had an average temperature of 80°F, a light intensity of 400 ft-c at table top, and a 16-hour photoperiod. At the end of each incubation period, the soils were sampled for ammonia and nitrate nitrogen. At the same time, twenty seeds of L. perenne L. were planted in the soil. Seedlings were grown for seventeen days and then excised at the soil surface and analyzed for total chlorophyll. Control of nitrification was obtained in both soils by the use of N-Serve at 0.50 and 1.0 ppm. Maintenance of NH3-N was longest in the clay loam soil at 1.0 ppm N-Serve. The increased persistence of NH3-N in the clay loam soil was attributed to the decrease in volatilization of N-Serve by adsorption to the organic matter and by the bonding of ammonium nitrogen to the clay fraction of the soil. Chlorophyll content of the ryegrass plants was increased in all treatments for both soils during the period of time in which ammonium nitrogen was most prevalent. Urea in conjunction with N-Serve promoted the highest concentrations of chlorophyll by prolonging the availability of ammonium nitrogen. The ammonium released from the ureaformaldehyde treatments nitrified rapidly and did not enhance chlorophyll synthesis in the ryegrass seedlings

The Effects of N-Serve on the Availability of Urea and Ureaformaldehyde Nitrogen on Lolium perenne L.

Laboratory experiments were conducted to determine the effect of N-Serve (DOW) on the availability of urea nitrogen and the subsequent greening effect on perennial ryegrass (Lolium perenne L.) seedlings as compared to the availability of nitrogen and subsequent greening from a controlled release ureaformaldehyde fertilizer. A low organic matter sandy loam soil and a high organic matter clay loam soil were used in this study. Soil treatments of urea and ureaformaldehyde fertilizers were applied and incorporated at concentrations of 0, 25, 38, and 50 ppm-N. N-Serve at concentrations of 0.25, 0.50, and 1.0 ppm active ingredient were applied and incorporated with the three highest urea concentrations in all possible combinations. Two hundred grams of soil were placed in styrofoam cups. For each soil, there were six trials corresponding to incubation periods of 0, 2, 3, 4, 5, and 6 weeks. All treatments were replicated three times per each trial. Soil water was maintained at field capacity (by weight) throughout the experiment. All cups were incubated in a room which had an average temperature of 80°F, a light intensity of 400 ft-c at table top, and a 16-hour photoperiod. At the end of each incubation period, the soils were sampled for ammonia and nitrate nitrogen. At the same time, twenty seeds of L. perenne L. were planted in the soil. Seedlings were grown for seventeen days and then excised at the soil surface and analyzed for total chlorophyll. Control of nitrification was obtained in both soils by the use of N-Serve at 0.50 and 1.0 ppm. Maintenance of NH3-N was longest in the clay loam soil at 1.0 ppm N-Serve. The increased persistence of NH3-N in the clay loam soil was attributed to the decrease in volatilization of N-Serve by adsorption to the organic matter and by the bonding of ammonium nitrogen to the clay fraction of the soil. Chlorophyll content of the ryegrass plants was increased in all treatments for both soils during the period of time in which ammonium nitrogen was most prevalent. Urea in conjunction with N-Serve promoted the highest concentrations of chlorophyll by prolonging the availability of ammonium nitrogen. The ammonium released from the ureaformaldehyde treatments nitrified rapidly and did not enhance chlorophyll synthesis in the ryegrass seedlings

A prototypical model for tensional wrinkling in thin sheets

The buckling and wrinkling of thin films has recently seen a surge of interest among physicists, biologists, mathematicians and engineers. This has been triggered by the growing interest in developing technologies at ever decreasing scales and the resulting necessity to control the mechanics of tiny structures, as well as by the realization that morphogenetic processes, such as the tissue-shaping instabilities occurring in animal epithelia or plant leaves, often emerge from mechanical instabilities of cell sheets. While the most basic buckling instability of uniaxially compressed plates was understood by Euler more than 200 years ago, recent experiments on nanometrically thin (ultrathin) films have shown significant deviations from predictions of standard buckling theory. Motivated by this puzzle, we introduce here a theoretical model that allows for a systematic analysis of wrinkling in sheets far from their instability threshold. We focus on the simplest extension of Euler buckling that exhibits wrinkles of finite length - a sheet under axisymmetric tensile loads. This geometry, whose first study is attributed to Lam´e, allows us to construct\ud a phase diagram that demonstrates the dramatic variation of wrinkling patterns from near-threshold to far-from-threshold conditions. Theoretical arguments and comparison to experiments show that for thin sheets the far-from-threshold regime is expected to emerge under extremely small compressive loads, emphasizing the relevance of our analysis for nanomechanics applications

Capillary deformations of bendable films

We address the partial wetting of liquid drops on ultrathin solid sheets resting on a deformable foundation. Considering the membrane limit of sheets that can relax compression through wrinkling at negligible energetic cost, we revisit the classical theory for the contact of liquid drops on solids. Our calculations and experiments show that the liquid-solid-vapor contact angle is modified from the Young angle, even though the elastic bulk modulus (E) of the sheet is so large that the ratio between the surface tension γ and E is of molecular size. This finding establishes a new type of “soft capillarity” that stems from the bendability of thin elastic bodies rather than from material softness. We also show that the size of the wrinkle pattern that emerges in the sheet is fully predictable, thus resolving a puzzle noticed in several previous attempts to model “drop-on-a-floating-sheet” experiments, and enabling a reliable usage of this setup for the metrology of ultrathin films

Unintended weight loss in the elderly living at home: the aged in homecare project (Adhoc)

Objective: To describe associations between unintended weight loss (UWL) and characteristics of nutritional status. Design: A comparative cross-sectional assessment study at 11 sites in Europe. The target population was a stratified random sample of 4,455 recipients of home care (405 in each random sample from 11 urban areas) aged 65 years and older. Measurements: the Resident Assessment Instrument for Home Care, version 2.0. Epidemiological and medical characteristics of clients and service utilisation were recorded in a standardized, comparative manner. UWL was defined as information of 5% or more weight loss in the last 30 days (or 10% or more in the last 180 days). Results: The final sample consisted of 4,010 persons; 74% were female. The mean ages were 80.9 ± 7.5 years (males) and 82.8 ± 7.3 years (females). No associations were found between single diagnoses and UWL, except for cancer. Cancer patients were excluded from further analyses. Persons with a Cognitive Performance Scale value (CPS) > 3 (impaired) had increased risk of UWL (OR = 2.0) compared with those scoring < 3 (less impaired). Only in the oldest group did we find a significant association between UWL and reduction in ADL and IADL functions, comparing those who scored 3 or less with those who scored more than 3 (disabled). A binary logistic regression model explained 26% of UWL: less than one meal/day, reduced appetite, malnutrition, reduced social activity, experiencing a flare-up of a recurrent or chronic problem, and hospitalisation were important indicators. Conclusion: We recommend a regular comprehensive assessment in home care to identify clients with potential risk factors for weight loss and malnutrition, in particular those discharged from hospital, and those with physical dependency or cognitive problems. This study may provide incentives to create tailored preventive strategies

Home care needs of extremely obese elderly european women

Objective: To examine the health and needs of extremely obese women aged over 65 years receiving home care in Europe. Study design: A cross-sectional assessment study based on the Aged in Home Care (AdHOC) project recruited 2974 women aged 65 or over who were receiving home care at 11 sites in European countries. Extreme obesity was defined as ‘Obesity of such a degree as to interfere with normal activities, including respiration’. Main outcome measures: Resident Assessment Instrument for Home Care (RAI-HC version 2.0); Activity of Daily Living Scale; Instrumental Activity of Daily Living Scale; the Minimum Data Set Cognitive Performance Scale; and a health profile. Results: One hundred and twenty women (4.0%) were extremely obese. They were younger than their thinner counterparts, with a median age of 78.3 versus 83.3 years, and they more often had multiple health complaints and needed more help with mobility outside the home. The extremely obese had received home care longer than the non-extremely obese (median 28.7 versus 36.6 months). Extremely obese women also needed more help with personal care than the other group and, due to lower age, they were less cognitively impaired. Conclusions: Extreme obesity is a problem that increasingly affects home care of elderly women

Identification of Metabolic Pathways Essential for Fitness of <i>Salmonella</i> Typhimurium <i>In Vivo</i>

Bacterial infections remain a threat to human and animal health worldwide, and there is an urgent need to find novel targets for intervention. In the current study we used a computer model of the metabolic network of Salmonella enterica serovar Typhimurium and identified pairs of reactions (cut sets) predicted to be required for growth in vivo. We termed such cut sets synthetic auxotrophic pairs. We tested whether these would reveal possible combined targets for new antibiotics by analyzing the performance of selected single and double mutants in systemic mouse infections. One hundred and two cut sets were identified. Sixty-three of these included only pathways encoded by fully annotated genes, and from this sub-set we selected five cut sets involved in amino acid or polyamine biosynthesis. One cut set (asnA/asnB) demonstrated redundancy in vitro and in vivo and showed that asparagine is essential for S. Typhimurium during infection. trpB/trpA as well as single mutants were attenuated for growth in vitro, while only the double mutant was a cut set in vivo, underlining previous observations that tryptophan is essential for successful outcome of infection. speB/speF,speC was not affected in vitro but was attenuated during infection showing that polyamines are essential for virulence apparently in a growth independent manner. The serA/glyA cut-set was found to be growth attenuated as predicted by the model. However, not only the double mutant, but also the glyA mutant, were found to be attenuated for virulence. This adds glycine production or conversion of glycine to THF to the list of essential reactions during infection. One pair (thrC/kbl) showed true redundancy in vitro but not in vivo demonstrating that threonine is available to the bacterium during infection. These data add to the existing knowledge of available nutrients in the intra-host environment, and have identified possible new targets for antibiotics