Soil Temperature Mediated Seedling Emergence and Field Establishment in Bentgrass Species and Cultivars During Spring in the Northeastern United States

Reestablishment of damaged golf greens and fairways planted to creeping bentgrass (Agrostis stolonifera), colonial bentgrass (A. capillaris), and velvet bentgrass (A. canina) is a common practice following winter injuries. Identifying bentgrass species (Agrostis sp.) and cultivars with the potential to establish under low soil temperatures would be beneficial to achieving more mature stands earlier in the spring. Twelve bentgrass cultivars, including seven cultivars of creeping bentgrass (007, 13-M, Declaration, L-93, Memorial, Penncross, and T-1), two colonial bentgrass cultivars (Capri and Tiger II), and three velvet bentgrass cultivars (Greenwich, SR-7200, and Villa), along with \u27Barbeta\u27 perennial ryegrass (Lolium perenne) were evaluated for grass cover in the field during early spring. Bentgrass species and cultivars were seeded in the field at the same seed count per unit area. Soil temperatures were monitored in unneeded check plots from initial planting date on 8 Apr. to termination on 29 May 2013. Soil temperatures increased linearly during the 52-day experimental period from 4.7 to 23.5 degrees C. All species and cultivars emerged at approximate to 10 degrees C soil temperature. Bentgrass species and cultivars varied only 2 to 3 days in their initial seedling emergence, while days varied among bentgrasses from 5.5 days (to 10% cover) to 8.6 days (to 90% cover). All velvet bentgrass cultivars required higher soil temperatures (13.6 degrees C) and more time (26 days) following initial seedling emergence to establish to 90% cover in the early spring. Creeping bentgrass cultivars 007, 13-M, and Memorial, along with colonial bentgrass cultivars Capri and Tiger II, were statistically equal to \u27Barbeta\u27 perennial ryegrass in their capacity after seedling emergence to achieve faster cover at lower soil temperatures. Heavier (larger) bentgrass seed was associated with faster cover during the early stages of establishment, but seed size was uncorrelated with establishment during later stages from 50% to 90% cover

Unintended and accidental medical radiation exposures in radiology: guidelines on investigation and prevention

This paper sets out guidelines for managing radiation exposure incidents involving patients in diagnostic and interventional radiology. The work is based on collation of experiences from representatives of international and national organizations for radiologists, medical physicists, radiographers, regulators, and equipment manufacturers, derived from an International Atomic Energy Agency Technical Meeting. More serious overexposures can result in skin doses high enough to produce tissue reactions, in interventional procedures and computed tomography, most notably from perfusion studies. A major factor involved has been deficiencies in training of staff in operation of equipment and optimization techniques. The use of checklists and time outs before procedures commence, and dose alerts when critical levels are reached during procedures can provide safeguards to reduce risks of these effects occurring. However, unintended and accidental overexposures resulting in relatively small additional doses can take place in any diagnostic or interventional X-ray procedure and it is important to learn from errors that occur, as these may lead to increased risks of stochastic effects. Such events may involve the wrong examinations, procedural errors, or equipment faults. Guidance is given on prevention, investigation and dose calculation for radiology exposure incidents within healthcare facilities. Responsibilities should be clearly set out in formal policies, and procedures should be in place to ensure that root causes are identified and deficiencies addressed. When an overexposure of a patient or an unintended exposure of a foetus occurs, the foetal, organ, skin and/or effective dose may be estimated from exposure data. When doses are very low, generic values for the examination may be sufficient, but a full assessment of doses to all exposed organs and tissues may sometimes be required. The use of general terminology to describe risks from stochastic effects is recommended rather than calculation of numerical values, as these are misleading when applied to individuals

Interspecific comparisons of C\u3csub\u3e3\u3c/sub\u3e turfgrass for tennis use: II. Investigaion of ball friction, ball bounce, and associated factors in replicated grass courts

Tennis is played on many different surfaces including natural grass, which plays fast because of low ball bounce (i.e., coefficient of restitution [COR]) and low ball‐to‐surface friction (coefficient of friction [COF]) that increase the pace (ball speed) of tennis. Effects of various C3 turfgrasses on COF and COR have not been investigated. Our objectives were to evaluate eight cultivars of various species randomized within three official size tennis courts: (a) ‘Keeneland’ Kentucky bluegrass (Poa pratensis L., KB), (b) ‘Rubix’ KB, (c) ‘Villa’ velvet bentgrass (Agrostis canina L., VBG), (d) ‘Puritan’ colonial bentgrass (Agrostis capillaris L., CL), (e) ‘007’ creeping bentgrass (Agrostis stolonifera L., CB), (f) fine fescue (Festuca sp., FF) mixture, (g) ‘Karma’ perennial ryegrass (Lolium perenne L, PR), and (h) ‘Wicked’ PR. Friction was measured using a weighted sled and ball bounce (BB) to derive COR was measured using a vertical drop height of 254 cm. Bounce (i.e., COR) to satisfy the International Tennis Federation (ITF) minimum of 50% BB (COR = 0.70) was not observed on any of the species evaluated. Species such as FF and PR were able to achieve BB to satisfy the ITF 80% BB minimum to that observed on smooth concrete. Linear regression indicated that 170g of surface hardness for FF and PR to as much as 200g on KB and higher on BG may be needed to achieve a COR = 0.70. Hemi‐ and lignocellulose cell wall fractions were correlated with COR and COF but exhibited significant and opposite relationships. Achieving higher COF may be a more practical means to slow court pace of notoriously fast grass courts. Future research will be needed to investigate the effects of cultural practices on COF

On-line analyte preconcentration with atomic spectrometric detection

Pre-concentration of analytes, or matrix removal to overcome interferences using mini- or micro-columns of exchange media prior to atomic spectrometric detection is becoming increasingly more common. This paper is a review of some of the more recent applications of chelating, ion exchange and other resins and gels that have been used to accomplish this

Automated cold vapour flow-injection analysis of mercury at high concentrations

Continuous-flow cold vapour- atomic fluorescence spectrometry is shown to be an extremely sensitive technique for the determination of mercury with detection limits typically below 0.01 μg l-1. Linear calibration ranges were found to be at least four orders of magnitude (i.e. up to 0.1 mg l-1). Samples with concentrations exceeding the linear range are susceptible to self-absorption, and may, in severe cases, cause carry-over problems between samples. The flow-injection approach has been utilized to extend the upper limit of the linear calibration range allowing determinations up to 10 mg l-1 of mercury. A range of certified reference materials and zinc battery anodes have been successfully analysed with a minimal number of sample dilutions

Limitations of chlorine disinfection of human excreta: implications for Ebola disease control

Various NGO guidelines suggest that human excreta may be disinfected by the application of concentrated (e.g., 0.5%) chlorine solutions. However, chlorine-based disinfectants are thought to rapidly lose their bactericidal and virucidal properties in contact with high levels of organic matter and chlorine application results in the production of toxic chlororganic compounds. To evaluate the disinfection efficacy of chlorine solutions (HTH, NaDCC and household bleach) against viruses and bacteria within excreta matrices, laboratory-scale disinfection experiments were undertaken. Human excreta matrices containing raw wastewater, with 0%, 10% and 20% (w/v) added faecal sludge, were disinfected with chlorine solutions at a ratio of 1:10 (chlorine solution: excreta matrix). Contact time was set at 30 minutes and bacterial (FC and IE) and viral (SOMPH) indicators were used to measure disinfection efficacy. Results demonstrated that at high levels of solids content, disinfection efficacy was significantly reduced. These results support the need to find a more effective means of disinfecting human excreta in future Ebola outbreaks

Thermal degradation analysis and XRD characterisation of fibre-forming synthetic polypropylene containing nanoclay

Flammability of synthetic fibres is significantly worse than that of bulk polymers because of the high surface area to volume ratio and the low tolerance to high filler loadings in the fibre production process. Introducing nanocomposite structures has the potential to enhance the char formation at relatively low loadings of nanoparticulate fillers and hence can reduce the flammability of synthetic polymers and fibres. This paper reports thermal degradation analysis results in conjunction with TG analysis under different atmospheres and further studies of X-ray diffraction characterisation of fibre-forming polypropylene containing selected dispersed nanoclays. The concentrations of hydrocarbons, carbon monoxide and carbon dioxide released during the TG analysis have been monitored and analysed by using a combined electrochemical infrared analyser. The intensity changes of the crystallinity peaks and nanoclay peaks in the polymer and composites are discussed

Evaluation of low-cost phage-based Microbial Source Tracking tools for elucidating human fecal contamination pathways in Kolkata, India

Phages, such as those infecting Bacteroides spp., have been proven to be reliable indicators of human fecal contamination in microbial source tracking (MST) studies, and the efficacy of these MST markers found to vary geographically. This study reports the application and evaluation of candidate MST methods (phages infecting previously isolated B. fragilis strain GB-124, newly isolated Bacteroides strains (K10, K29, and K33) and recently isolated Kluyvera intermedia strain ASH-08), along with non-source specific somatic coliphages (SOMCPH infecting strain WG-5) and indicator bacteria (Escherichia coli) for identifying fecal contamination pathways in Kolkata, India. Source specificity of the phage-based methods was first tested using 60 known non-human fecal samples from common animals, before being evaluated with 56 known human samples (municipal sewage) collected during both the rainy and dry season. SOMCPH were present in 40-90% of samples from different animal species and in 100% of sewage samples. Phages infecting Bacteroides strain GB-124 were not detected from the majority (95%) of animal samples (except in three porcine samples) and were present in 93 and 71% of the sewage samples in the rainy and dry season (Mean = 1.42 and 1.83 log(10)PFU/100mL, respectively), though at lower levels than SOMCPH (Mean = 3.27 and 3.02 log(10)PFU/100mL, respectively). Phages infecting strain ASH-08 were detected in 89 and 96% of the sewage samples in the rainy and dry season, respectively, but were also present in all animal samples tested (except goats). Strains K10, K29, and K30 were not found to be useful MST markers due to low levels of phages and/or co-presence in non-human sources. GB-124 and SOMCPH were subsequently deployed within two low-income neighborhoods to determine the levels and origin of fecal contamination in 110 environmental samples. E. coli, SOMCPH, and phages of GB-124 were detected in 68, 42, and 28% of the samples, respectively. Analyses of 166 wastewater samples from shared community toilets and 21 samples from sewage pumping stations from the same districts showed that SOMCPH were present in 100% and GB-124 phages in 31% of shared toilet samples (Median = 5.59 and <1 log(10) PFU/100 mL, respectively), and both SOMCPH and GB-124 phages were detected in 95% of pumping station samples (Median = 5.82 and 4.04 log(10) PFU/100 mL, respectively). Our findings suggest that GB-124 and SOMCPH have utility as low-cost fecal indicator tools which can facilitate environmental surveillance of enteric organisms, elucidate human and non-human fecal exposure pathways, and inform interventions to mitigate exposure to fecal contamination in the residential environment of Kolkata, India