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Accurate determinations of the elemental composition of coal by classical methods can be quite difficult and are normally very time consuming. X-ray fluorescence utilizing the powder method, however, has the ability of providing accurate and rapid analyses. Unfortunately, well characterized standards, although available, are not plentiful. In addition, the durability or stability of ground and pelletized coal samples is poor resulting in deterioration with time. As a result, artificial coal standards were prepared from certified geological materials by fusing in lithium-tetra-borate in percentages approximating expected ash contents and compositions in coal. Since the lithium-tetra-borate comprises about the same percentage of the standard as does the carbon, hydrogen, and oxygen in coal, the ground and pelletized coal sample can be assayed against the fused calibration curves by compensating for the differences in the mass absorption coefficients of the two matrices.
Chemical analysis of geological materials such as nickel ores has been accomplished by atomic absorption (1,3) x-ray fluorescence (11,14) and conventional wet methods (10). Procedures utilizing these techniques are capable of producing excellent results but are often difficult and time consuming.
Minerals often present serious problems in chemical analysis by wet methods. X-ray analysis can therefore offer the analyst considerable savings in time providing the obstacles which exist are understood and minimized or eliminated. The most serious problems to solve are absorption and enhancement effects, mineralogical differences among samples, sample preparation, and particle size effects which often influence the intensities of the analytical lines. In addition, the element of interest may be of low concentration in a variable and unknown matrix.
A procedure using tube excited energy dispersive x-ray fluorescence analysis with interelement corrections has been developed for multielement analysis of major and trace elements and ash content of coal, coke, and fly ash. The procedure uses pressed pellets and an exponential correction for interelement effects. The average deviations ranged from about 0.0003% for V at an average concentration of about .003% to 0.1% for S at an average concentration of 4%. About 25 elements were measured and 100 second minimum detectable concentrations ranged from about one part per million for elements near arsenic to about one tenth of one percent for sodium.
Recent developments in analytical techniques and software have allowed the accurate quantitative determinations of both the major and minor elements in stainless steels by energy dispersive x-ray fluorescence. The successful analysis of 300 and 400 series stainless steel is reported utilizing this technique. The analysis of this type of material represents one of the most severe tests of the method due to numerous peak overlaps and interelement effects such as absorption and enhancement.
Sixteen standards of ASTM 300 series and ten 400 series were prepared by polishing on a 220 grit aluminum oxide belt and subsequently washing the surface in absolute methanol. Analyses were performed with an EG&G ORTEC 6110 Tube Excited Fluorescence Analyzer utilizing a dual anode (Rh/W) x-ray tube. Peak deconvolutions and interelement corrections were made with a 16K PDP-11/05 computer utilizing the program FLINT (1). Utilization of spectral deconvolutions and interelement corrections yields a relative accuracy of approximately IX of the concentrations of the major elements.
A rapid multielement analysis procedure for cement and ceramic type materials has been developed which uses pelletized powders and an exponential correction to the observed x-ray intensities. Only the more significant interactions are considered in an iterative process requiring a minimum of standards. The interaction coefficients are determined by a nonlinear multiple least squares fit of the standards. Average deviations obtained for the analysis of light elements in cement ranged from a low of 0.006% for K2O to a high of 0.13% absolute for SiO2.
There is increasing consumer resistance to feeding antibiotic performance enhancers to beef cattle which has created interest in the use of yeast cultures as an alternative. Yeast cultures such as Diamond V ‘XP’ (Rumenco) are produced by growing selected yeast strains (on a semi-solid medium under stressed conditions) which are then dried. Yeast cultures are now used in a considerable number of North American beef feed lots. The objective of this work was to evaluate the effect of feeding ‘XP’ Yeast to finishing beef cattle on a typical UK grass silage-based diet.
A large outbreak of Legionnaires’ disease occurred at a California state prison in August 2015. We conducted environmental and epidemiological investigations to identify the most likely source of exposure and characterise morbidity. Sixty-four inmates had probable Legionnaires’ disease; 14 had laboratory-confirmed legionellosis. Thirteen (17%) inmates were hospitalised; there were no deaths. Ill inmates were more likely to be ⩾65 years old (P < 0.01), have the chronic obstructive pulmonary disease (P < 0.01), diabetes mellitus (P = 0.02), hepatitis C infection (P < 0.01), or end-stage liver disease (P < 0.01). The case-patients were in ten housing units throughout the prison grounds. All either resided in or were near the central clinical building (for appointments or yard time) during their incubation periods. Legionella pneumophila serogroup 1 was cultured from three cooling towers on top of the central medical clinic (range, 880–1200 cfu/ml). An inadequate water management program, dense biofilm within the cooling towers, and high ambient temperatures preceding the outbreak created an ideal environment for Legionella sp. proliferation. All state prisons were directed to develop local operating procedures for maintaining their cooling towers and the state health department added a review of the maintenance plans to their environmental inspection protocol.
The feeding of lowland sheep on straw-based systems during pregnancy was developed at ADAS Rosemaund during the last decade (Davies and Chappie 1995). Results showed that ewe and lamb performance were satisfactory, providing adequate compound supplementation was fed. Whole barley and soya bean meal has been the standard ration, but feeds based on high protein molassed sugar beet feed (Probeet Trident Feed) and maize distiller's dark grains could improve palatability and be easier to feed. The objective of this work was to evaluate the effects on ewe and lamb performance of feeding sugar beet feeds and maize distiller's dark grains to pregnant ewes on a straw-based feeding system.
Feeding of lowland sheep on straw-based systems during pregnancy and in early lactation has shown that ewe and lamb performance can be satisfactory, providing adequate compound supplementation is fed (Davies and Chapple, 1995). Whole barley and soya bean meal has been the standard ration. However, soya bean meal is imported and not fully traceable. Experiments with January- and March-lambing ewes have shown that traceable, homeproduced feeds based on equal quantities of molassed sugar beet feed and either maize or barley distillers grains can replace a barley/soya supplement when fed with straw or silage-based diets in late pregnancy (Chapple et al., 1998 and 1999). The objective of this work was to evaluate the effects on ewe and lamb performance of feeding sugar beet feeds with distillers grains to March-lambing ewes rearing twin lambs at pasture.
Feeding lowland sheep on straw-based systems during pregnancy (Davies and Chapple 1995) has shown that ewe and lamb performance can be satisfactory, providing adequate compound supplementation was fed. Whole barley and soya bean meal has been the standard ration. Experiments with March-lambing ewes (Chapple et al., 1997) has shown that feeds based on molassed sugar beet feed and maize distillers dark grains can replace a barley/soya supplement. The objective of this work was to evaluate the effects on ewe and lamb performance of feeding sugar beet feeds with higher levels of distillers grains to January-lambing ewes on straw-based and big-bale silage systems during pregnancy and early lactation.
The degree of processing of protein-rich feeds affects their physical properties. Seeds which are less comminuted, whether cracked or rolled, may have properties which make their behaviour, in the rumen and postruminally, distinct from fine ground material and which may therefore alter their performance as feed proteins. The use of lupin seeds as a replacement for soya in ruminant diets has been demonstrated (Moss et al, 1997). This project aimed to assess whether the processing of lupin seeds, either hammer milling or rolling, affected the performance of young cattle fed the seed as their principal source of protein.
Feeding lowland sheep on straw-based systems during pregnancy is practised on many livestock/arable farms. Simple mixes of molassed sugar beet feed and distillers dark grains have been cost effective supplements for March-lambing ewes fed straw and produced satisfactory ewe and lamb performance (Chapple et al., 1998 and 2001). An ensiled mix of pressed sugar beet pulp and dried maize distillers grains (Praize, Trident Feeds) has been fed as the sole diet for finishing lambs (Pattinson et al., 2001) but there is little information on feeding Praize to pregnant ewes. The objective of this study was to compare ewe and lamb performance when March-lambing ewes were fed on a straw-based system and supplemented with either a cereal/protein home-mix, Praize or one of two dried sugar beet pulp/protein mixes.
Feeding of lowland sheep on straw-based systems during pregnancy and in early lactation has shown that ewe and lamb performance can be satisfactory, providing adequate compound supplementation is fed (Davies and Chapple, 1995). Whole barley and soya bean meal has been the standard ration. However, soya bean meal is imported and may not be fully traceable. Maize or barley distillers fed with beans could provide traceable protein to replace soya bean meal in sheep diets. Experiments with housed early-lambing ewes and ewes suckling twin lambs at grass have shown that traceable feeds, based on molassed sugar beet and either maize or barley distillers grains, can replace a barley/soya supplement when fed with straw based diets in late pregnancy or at grass (Chapple et al., 1999 and 2000). The objective of this work was to evaluate the effects on ewe and lamb performance of feeding sugar beet feeds with distillers grains and beans to March-lambing ewes on a straw-based system.
We discuss the possible connection between supernova explosions (SN) and gamma-ray bursters (GRB) from the perspective of our current understanding of SN physics. Core collapse supernovae (SN) are the final stages of stellar evolution in massive stars during which the central region collapses, forms a neutron star (NS) or black hole, and the outer layers are ejected. Recent explosion scenarios assumed that the ejection is due to energy deposition by neutrinos into the envelope but detailed models do not produce powerful explosions. There is new and mounting evidence for an asphericity and, in particular, for axial symmetry in several supernovae which may be hard to reconcile within the spherical picture. The 3-D signatures are a key to understand core collapse supernovae and the GRB/SN connection. In this paper we study the effects and observational consequences of asymmetric explosions.
Direct numerical simulations (DNS) are used to investigate the unsteady flow over a model turbine blade tip at engine-scale Reynolds and Mach numbers. The DNS are performed with an in-house multiblock structured compressible Navier–Stokes solver. The particular case of a transonic tip flow is studied since previous work has suggested that compressibility has an important effect on the turbulent nature of the separation bubble at the inlet to the tip–casing gap and subsequent flow reattachment. The flow is simulated over an idealized tip geometry where the tip gap is represented by a constant-area channel with a sharp inlet corner to represent the pressure side edge of the turbine blade. The effects of free-stream disturbances, cross-flow and the pressure side boundary layer on the tip flow aerodynamics and heat transfer are studied. For ‘clean’ inflow cases we find that even at engine-scale Reynolds numbers the tip flow is intermittent in nature, i.e. neither laminar nor fully turbulent. The breakdown to turbulence occurs through the development of spanwise streaks with wavelengths of approximately 15 %–20 % of the gap height. Multidimensional linear stability analysis confirms the two-dimensional base state to be most unstable with respect to spanwise wavelengths of 25 % of the gap height. The linear stability analysis also shows that the addition of cross-flows with 25 % of the streamwise gap exit velocity increases the stability of the tip flow. This is confirmed by the DNS, which also show that the turbulence production is significantly reduced in the separation bubble. For the case when free-stream disturbances are added to the inlet flow, viscous dissipation and the rapid acceleration of the flow at the inlet to the tip–casing gap cause significant distortion of the vorticity field and reductions of turbulence intensity as the flow enters the tip gap. The DNS results also suggest that the assumption of the Reynolds analogy and a constant recovery factor are not accurate, in particular in regions where the skin friction approaches zero while significant temperature gradients remain, such as in the vicinity of flow reattachment.
To determine the impact of total household decolonization with intranasal mupirocin and chlorhexidine gluconate body wash on recurrent methicillin-resistant Staphylococcus aureus (MRSA) infection among subjects with MRSA skin and soft-tissue infection.
Three-arm nonmasked randomized controlled trial.
Five academic medical centers in Southeastern Pennsylvania.
Adults and children presenting to ambulatory care settings with community-onset MRSA skin and soft-tissue infection (ie, index cases) and their household members.
Enrolled households were randomized to 1 of 3 intervention groups: (1) education on routine hygiene measures, (2) education plus decolonization without reminders (intranasal mupirocin ointment twice daily for 7 days and chlorhexidine gluconate on the first and last day), or (3) education plus decolonization with reminders, where subjects received daily telephone call or text message reminders.
MAIN OUTCOME MEASURES
Owing to small numbers of recurrent infections, this analysis focused on time to clearance of colonization in the index case.
Of 223 households, 73 were randomized to education-only, 76 to decolonization without reminders, 74 to decolonization with reminders. There was no significant difference in time to clearance of colonization between the education-only and decolonization groups (log-rank P=.768). In secondary analyses, compliance with decolonization was associated with decreased time to clearance (P=.018).
Total household decolonization did not result in decreased time to clearance of MRSA colonization among adults and children with MRSA skin and soft-tissue infection. However, subjects who were compliant with the protocol had more rapid clearance
RF-plasma MBE was used to epitaxially grow 4 – 100-nm-thick metallic
β-Nb2N thin films on hexagonal SiC substrates. When the
N/Nb flux ratios are greater than one, the most critical parameter for
high-quality β-Nb2N is the substrate temperature. The X-ray
diffraction (XRD) of films grown between 775 °C and 850 °C
demonstrates pure β-Nb2N phase formation which was also
confirmed by X-ray photoelectron spectroscopy and transmission electron
microscopy measurements. Using the (0002) and (21
1) XRD peaks of a β-Nb2N film grown at 850
°C reveals a 0.68% lattice mismatch to the 6H-SiC substrate. This
suggests that β-Nb2N can be used for high-quality
metal/semiconductor heterostructures that cannot be fabricated at present.
Antibiotic treatment for asymptomatic bacteriuria (ASB) is prevalent but often contrary to published guidelines.
To evaluate risk factors for treatment of ASB.
Retrospective observational study.
A tertiary academic hospital, county hospital, and community hospital.
Hospitalized adults with bacteriuria.
Patients without documented symptoms of urinary tract infection per Infectious Diseases Society of America (IDSA) criteria were classified as ASB. We examined ASB treatment risk factors as well as broad-spectrum antibiotic usage and quantified diagnostic concordance between IDSA and National Healthcare Safety Network criteria.
Among 300 patients with bacteriuria, ASB was present in 71% by IDSA criteria. By National Healthcare Safety Network criteria, 71% of patients had ASB; within-patient diagnostic concordance with IDSA was moderate (kappa, 0.52). After excluding those given antibiotics for nonurinary indications, antibiotics were given to 38% (62/164) with ASB. Factors significantly associated with ASB treatment were elevated urine white cell count (65 vs 24 white blood cells per high-powered field, P<.01), hospital identity (hospital C vs A, odds ratio, 0.34 [95% CI, 0.14–0.80], P =.01), presence of leukocyte esterase (5.48 [2.35–12.79], P<.01), presence of nitrites (2.45 [1.11–5.41], P=.03), and Escherichia coli on culture (2.4 [1.2–4.7], P=.01). Of patients treated for ASB, broad-spectrum antibiotics were used in 84%.
ASB treatment was prevalent across settings and contributed to broad-spectrum antibiotic use. Associating abnormal urinalysis results with the need for antibiotic treatment regardless of symptoms may drive unnecessary antibiotic use.
Infect. Control Hosp. Epidemiol. 2016;37(3):319–326
During the Cretaceous and Paleogene, the Indian subcontinent was isolated as it migrated north from the east coast of Africa to collide with Asia. As it passed over the Reunion hotspot in the late Maastrichtian–early Danian, a series of lava flows extruded, known as the Deccan Traps. Also during this interval, there was a major mass-extinction event at the Cretaceous–Paleogene boundary, punctuated by a meteorite impact at Chicxulub, Mexico. What were the biological implications of these changes in paleogeography and the extensive volcanism in terms of biodiversity, evolution, and biogeography? By combining chronostratigraphic, paleosol, and paleobotanical data, an understanding of how the ecosystems and climates changed and the relative contributions of the Chicxulub impact, Deccan Traps volcanism, and paleogeographic isolation can be gained. Understanding relative ages of paleobotanical localities is crucial to determining floristic changes, and is challenging because different methods (e.g., magnetostratigraphy, radiometric dating, vertebrate and microfossil biostratigraphy) sometimes give conflicting answers, or have not been done for paleobotanical localities. Climatic data can be obtained quantitatively by studying paleosol geochemistry, as well as qualitatively by examining functional traits and nearest living relatives of fossil plants. An additional challenge is revising macrofossil data, which includes some confidently identified taxa and others with uncertain affinities. This is important for understanding ecosystem composition both spatially and temporally, as well as the biogeographic implications of an isolated India.
In this study, we evaluated the association between high-risk human papillomavirus (hrHPV) and the vaginal microbiome. Participants were recruited in Nigeria between April and August 2012. Vaginal bacterial composition was characterized by deep sequencing of barcoded 16S rRNA gene fragments (V4) on Illumina MiSeq and HPV was identified using the Roche Linear Array® HPV genotyping test. We used exact logistic regression models to evaluate the association between community state types (CSTs) of vaginal microbiota and hrHPV infection, weighted UniFrac distances to compare the vaginal microbiota of individuals with prevalent hrHPV to those without prevalent hrHPV infection, and the Linear Discriminant Analysis effect size (LEfSe) algorithm to characterize bacteria associated with prevalent hrHPV infection. We observed four CSTs: CST IV-B with a low relative abundance of Lactobacillus spp. in 50% of participants; CST III (dominated by L. iners) in 39·2%; CST I (dominated by L. crispatus) in 7·9%; and CST VI (dominated by proteobacteria) in 2·9% of participants. LEfSe analysis suggested an association between prevalent hrHPV infection and a decreased abundance of Lactobacillus sp. with increased abundance of anaerobes particularly of the genera Prevotella and Leptotrichia in HIV-negative women (P < 0·05). These results are hypothesis generating and further studies are required.