Minimising nutrient transfers from poultry litter field heaps

The high nutrient content of poultry litter poses a threat to water quality if managed incorrectly during storage. The aim of this study was to evaluate the transfers of nutrients from four methods of poultry litter heaps storage on six arable sites located in Northern Ireland. The methods investigated were; covered heaps, covered heaps with runoff diversion trenches, enveloped heaps, and enveloped heap with runoff diversion trenches. Facilities were installed at each site to capture runoff from the area surrounding the heaps, while changes in nutrient concentration in the soil profile below the heaps were also monitored. Compared to the control plots the presence of the poultry litter heaps did not have a significant impact on the concentrations of total phosphorus (TP) in runoff. However, soil P had a significant positive impact (P = 0.02) on the TP concentrations measured in runoff from plots. There was a significant decrease (P < 0.01) in NO₃ and NH₄ concentrations in runoff from poultry litter heaps plots. The presence of litter heaps had no impact on conductivity or biological oxygen demand. There was no change in soil P below the heaps however, there was a small increase in soil NO₃ concentration at 60–90 cm depth under heaps when compared with the control plots (P < 0.05), which was likely due to elevated soil temperatures under the heaps causing an increase in nitrification. The results demonstrate that poultry litter stored in field heaps poses a minimal risk to water quality if managed carefully.     

Uptake and transport by the ovine placenta of neutral nonmetabolizable amino acids with different transport system affinities

In 32 published reports in surgical patients, the preponderance of evidence from standard clinical measures of renal function (BUN and Cr) indicates the absence of renal toxicity following sevoflurane anesthesia. Studies of surgical patients receiving intermediate-duration sevoflurane with high or low fresh gas flow and long-duration sevoflurane with high fresh gas flow included sensitive measures of renal function and/or injury, which also indicate the absence of renal toxicity following sevoflurane anesthesia. Studies of surgical patients receiving long-duration sevoflurane with low fresh gas flow did not include sensitive measures. Seven studies in volunteers are not directly relevant to clinical practice but do raise the issue of whether it is important to apply sensitive measures of renal function and/or injury such as urine concentrations and/or excretion of NAG, beta 2M, alpha 1M, AAP, alpha GST, pi GST, gamma GTP, albumin, protein, and glucose and Cr clearance. Two studies of volunteers receiving prolonged sevoflurane anesthesia with fresh gas flow no greater than 2 L/min concluded that the potential for adverse renal effects of sevoflurane may exist. The other studies of volunteers did not. In 14 published reports of surgical patients in special conditions, the preponderance of evidence from standard clinical measures of renal function indicates the absence of renal toxicity. Studies with sensitive measures have been reported for some conditions where the kidney may be at increased risk (e.g., sevoflurane-induced hypotension, advanced age, and renal insufficiency and failure), are incomplete in others (e.g., hypertension and ischemic heart disease), and are missing in others (e.g., morbid obesity). Studies with sensitive measures of renal function and/or injury are also missing in an important group where the kidney may not be at increased risk--pediatric patients. Studies of other risk conditions, such as temporary ischemia, hemorrhagic hypotension, nephrotoxic antibiotics, kidney transplantation, and diabetes may provide additional information about the renal effects of sevoflurane.     

Changing perspectives on the importance of urban phosphorus inputs as the cause of nutrient enrichment in Lough Neagh

The scale and chronology of the phosphorus (P) enrichment of Lough Neagh, a large hypertrophic lake, was assessed using, as enrichment proxies, published palaeocological studies on diatoms and chironomid head capsules preserved in the lake sediments and, from 1974, monitoring data from the lake and its inflowing rivers. Enrichment commenced in 1880, and the scale and chronology of the diatom and chironomid records were similar up to 1960, but in the 1960s, chironomid accumulation rates increased dramatically, whereas diatom rates remained unchanged. From subsequent lake monitoring, the absence of a diatom response after 1960 was attributed to silica limitation so that P could be considered as the driver of increased diatom production only up to 1960. Using a coefficient for the demand for P by diatoms of 4 microg P mg SiO(2)(-1), it was calculated that the increased diatom production between 1881 and 1961 required an increase in lake P of 26 microg P l(-1). This value is close to the predicted increase of 22.5 microg P l(-1) in the lake caused by inputs of P from sewage treatment works and septic tanks. There was no evidence that diffuse source P contributed to enrichment over this period. Enrichment up to 1960 appears modest in comparison to subsequent years. From 1961 to 1974, lake P was estimated to have increased by 62 microg P l(-1), but only 25 microg P l(-1) of this increase was attributable to greater loadings of P from urban and septic tank sources. The enrichment response of chironomids at this time was also much greater than expected from a regression-derived relationship between urban P inputs and chironomid accumulation rates suggesting additional sources of P. The larger than expected increase in lake P was attributed to the onset of a significant internal loading of P and the commencement of an increase in diffuse source loadings of P. River monitoring has shown that diffuse P has increased steadily since 1974, more than counterbalancing a 40% reduction in urban P loadings that has taken place since 1980. By the end of the 20th century urban sources contributed only 19.7% of inflow P to Lough Neagh but lake P was 145 microg P l(-1) compared to an estimated concentration of 20 microg P l(-1) in 1881. Failure to control diffuse P sources has therefore been instrumental in the continued increase of lake P in Lough Neagh.     

Expression of the Drosophila 70,000 Dalton heat shock protein is translationally controlled in yeast

Plasmid pPW229, containing the 2.25 kilobase transcribed sequence for the 70,000 Dalton heat shock protein of Drosophila, was integrated into plasmid CV13 and used to transform Saccharomyces cerevisiae. Upon a heat shock, at 41 degrees C for 20 min, a new 70,000 Dalton protein appeared in the transformants. This protein was not detected in transformants grown at 23 degrees C, nor in transformants carrying the hybrid plasmid from which the structural gene for the 70,000 Dalton protein had been deleted. RNA was isolated from transformants grown at 23 degrees C and from transformants heat shocked at 41 degrees C. RNA complementary to the Drosophila heat shock gene was present in the transformants, grown either at 23 degrees C or heat shocked. No complementary RNA was detected in yeast cells transformed with the hybrid plasmid from which the structural gene had been deleted. The Drosophila heat shock gene in yeast appears to be transcribed constitutively but translated only under heat shock conditions.     

The applicability of digital PCR for the assessment of detection limits in GMO analysis

We investigate the applicability of using digital PCR to estimate absolute limits of detection and quantitation associated with the validation of traditional real-time PCR methods for analysis of genetically modified (GM) ingredients. We also demonstrate the use of dynamic arrays as a precursor in selecting suitable sample dilution levels for accurate copy number assessment using the aforementioned digital PCR. Additionally, we further explore the relevance of digital PCR in accurately quantifying plasmid copy numbers associated with a commercially available Certified Reference Material. The use of digital PCR has the advantage of facilitating absolute single molecule detection, therefore negating the necessity for standards on a calibration curve, and reducing associated matrix effects. The approaches described in this paper enable pre-existing validated protocols to be re-examined, and estimates based on an alternative approach using digital PCR to be used in order to objectively characterise sensitivity limits.     

Stopping powers of gases for 40 MeV/u tellurium ions

The stopping powers of six gaseous media have been measured for incident 40 MeV/u ¹²⁵Te heavy ions. The energy losses of ions in various “thicknesses” of gas have been accurately determined. The gases were confined in a cell. The amount of matter traversed by the ions was determined from temperature and pressure measurements. The beam energy before and after slowing down were measured using the LISE magnetic spectrometer at GANIL. These experimental gas stopping powers are lower by about 10% than the corresponding tabulated values for solid media. This means that the gas–solid effect is still significant at 40 MeV/u for Te ions. The projectile effective charges derived from these measurements depend on the target atomic number, thus confirming the trend observed in previous experiments performed with lighter ions or at lower energies.     

Cladding Glass Development for Semiconductor Core Optical Fibers

Glass-clad optical fibers comprising a crystalline semiconductor core have garnered considerable recent attention for their potential utility as novel waveguides for applications in nonlinear optics, sensing, power delivery, and biomedicine. To date, cladding compositions have relied on commercially-available expedients and have not been tailored for the specific semiconductor core nor the application. In this work, more-optimum silicate and nonoxide glass compositions are developed for unary (Si, Ge), binary (InSb, GaAs), and ternary (GaAlSb) semiconductor cores based on two main design criteria: (1) matching the thermal expansion coefficient between semiconductor core and glass cladding and (2) matching the viscosity-temperature dependences such that the cladding glass draws into fiber at a temperature slightly above the melting point of the semiconductor. While this latter requirement is critical to the molten core fabrication method, which offers a practical approach to long fiber lengths at acceptable manufacturing speeds (>m/s), these compositions are more broadly applicable to other semiconductor fiber processing methods. Preliminary experimental results on silicon core optical fiber are provided and show a marked diminution in oxygen content relative to analogous fibers drawn using a pure silica cladding.