2,787 research outputs found
Living roots magnify the response of soil organic carbon decomposition to temperature in temperate grassland.
Increasing atmospheric carbon dioxide (CO2) concentration is both a strong driver of primary productivity and widely believed to be the principal cause of recent increases in global temperature. Soils are the largest store of the world's terrestrial C. Consequently, many investigations have attempted to mechanistically understand how microbial mineralisation of soil organic carbon (SOC) to CO2 will be affected by projected increases in temperature. Most have attempted this in the absence of plants as the flux of CO2 from root and rhizomicrobial respiration in intact plant-soil systems confounds interpretation of measurements. We compared the effect of a small increase in temperature on respiration from soils without recent plant C with the effect on intact grass swards. We found that for 48 weeks, before acclimation occurred, an experimental 3 °C increase in sward temperature gave rise to a 50% increase in below ground respiration (ca.0.4 kg C m−2; Q10=3.5), whereas mineralisation of older SOC without plants increased with a Q10 of only 1.7 when subject to increases in ambient soil temperature. Subsequent 14C dating of respired CO2 indicated that the presence of plants in swards more than doubled the effect of warming on the rate of mineralisation of SOC with an estimated mean C age of ca.8 y or older relative to incubated soils without recent plant inputs. These results not only illustrate the formidable complexity of mechanisms controlling C fluxes in soils, but also suggest that the dual biological and physical effects of CO2 on primary productivity and global temperature have the potential to synergistically increase the mineralisation of existing soil C
Milk Testing in Practice
DigestThere is a great variation in the producing ability of different cows. Testing eliminates the unprofitable cow and enables one to select the very best animals for breeding stock. Page 419. There are six plans or systems for determining the production of each cow. All of these plans are feasible. It is very important that an accurate sample of milk be secured and that it be properly preserved until tested. Page 420-421.Occasional farmers are keeping private records of the production of their cows. Page 422.Boys\u27 milk testing clubs have been organized for the purpose of testing individual cows. Page 422.Creamery and cream station operators cooperate to the extent of testing samples from individual cows once a month. Page 422.The cow testing association is an excellent means of determining production. Page 422-423.Official and semi-official testing is used only in the case of purebred cows. This method is absolutely accurate and forms the basis for world\u27s records. Page 423, 426.The Babcock test for butterfat has become universal. Page 427.The important steps in testing milk are sampling, measuring (17.6cc), adding acid (17.5cc), centrifuging, successive additions of hot water, tempering and reading. Pages· 427-430.The important steps in testing cream are sampling, weighing, (9 or 18 grams), adding acid, adding water if necessary, centrifuging, tempering and reading. Page 430.The testing of skim milk is similar to that of milk except that it calls for greater speed and length of time in centrifuging. Page 430-431.Defective tests are caused by specific conditions which can be corrected. Page 431.Cow testing eliminates the cow kept at a loss, raises the average production of the herd and increases the profits from dairying. Page 431
Mod p Base Change transfer for GL(2)
We discuss Base Change functoriality for mod p eigenforms for GL(2) over number fields. We carry out systematic computer experiments and collect data supporting its existence in cases of field extensions K/F where F is imaginary quadratic and K is CM quartic
Oil quality in diesel engines with on line oil cleaning using a heated lubricating oil recycler
A method of cleaning the oil on line was investigatedusing a bypass fine particulate filter followed by an infra
red heater to remove water and light diesel fractions in
the oil. This was tested on a range of on road vehicles
and a Ford 1.8 litre IDI passenger car engine on a test
bed. Comparison was made with the oil quality on the
same vehicles and engines without the on-line recycler.
Test times were from 200 to 1500 hours of oil ageing and
some of the tests showed that the oil quality was still
good after 4 times the normal oil life. The results showed
that the on line oil recycler cleaning system reduced the
rate of fall of the TBN and rate of increase of the TAN.
There was a very significant reduction in the soot in oil
and the fuel dilution. There was also a consistent reduction
in all the wear metals apart from copper and a
decrease in the rate of reduction of oil additives. There
was also measured on the Ford IDI engine a 5% reduced
fuel consumption. Many of these effects were attributed
to an influence of the cleaner oil on reduced engine
deposits
Oil quality in diesel engines with on line oil cleaning using a heated lubricating oil recycler
A method of cleaning the oil on line was investigatedusing a bypass fine particulate filter followed by an infra
red heater to remove water and light diesel fractions in
the oil. This was tested on a range of on road vehicles
and a Ford 1.8 litre IDI passenger car engine on a test
bed. Comparison was made with the oil quality on the
same vehicles and engines without the on-line recycler.
Test times were from 200 to 1500 hours of oil ageing and
some of the tests showed that the oil quality was still
good after 4 times the normal oil life. The results showed
that the on line oil recycler cleaning system reduced the
rate of fall of the TBN and rate of increase of the TAN.
There was a very significant reduction in the soot in oil
and the fuel dilution. There was also a consistent reduction
in all the wear metals apart from copper and a
decrease in the rate of reduction of oil additives. There
was also measured on the Ford IDI engine a 5% reduced
fuel consumption. Many of these effects were attributed
to an influence of the cleaner oil on reduced engine
deposits
Petrography and Geochemistry of Metals in Almahata Sitta Ureilites
Ureilites are ultramafic achondrites, predominantly composed of olivine and pyroxenes with accessory carbon, metal and sulfide. The majority of ureilites are believed to represent the mantle of the ureilite parent body (UPB) [1]. Although ureilites have lost much of their original metal [2], the metal that remains retains a record of the formative processes. Almahata Sitta is predominantly composed of unbrecciated ureilites with a wide range of silicate compositions [3,4]. As a fall it presents a rare opportunity to examine fresh ureilite metal in-situ, and analyzing their highly siderophile element (HSE) ratios gives clues to their formation. Bulk siderophile element analyses of Almahata Sitta fall within the range observed in other ureilites [5]. We have examined the metals in seven ureilitic samples of Almahata Sitta (AS) and one associated chondrite fragment (AS#25)
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Bibliography on CO{sub 2} Effects on Vegetation and Ecosystems: 1990-1999 Literature
Mechanically coupled laminates with balanced plain weave
Definitive listings of laminate stacking sequences are derived for balanced plain weave laminated materials, assuming each layer is composed of the same material with constant thickness throughout and that standard ply angle orientations 0, 90, and ±45° are adopted; consistent with industrial design practice. A single layer of balanced plain weave material is shown to be immune to thermal distortion following a standard high temperature manufacturing process, which implies that all laminates constructed of this material possess what is commonly referred to as the hygro-thermally curvature-stable or warp-free condition, irrespective of the individual ply orientations used or the laminate stacking sequence definition. A single uncoupled parent laminate class is shown to contain sub-groups with extensionally isotropic and fully isotropic properties that are invariant with off-axis orientation of the principal material axes with respect to the system or structural axes. By contrast a single mechanically coupled parent laminate class is shown to give rise to seven unique forms of coupled laminate through judicious off-axis orientation. Invariant off-axis properties are also identified in coupled laminate designs. Finally, example calculations, abridged stacking sequence listings and design data are presented
Tackling Systematic Errors in Quantum Logic Gates with Composite Rotations
We describe the use of composite rotations to combat systematic errors in
single qubit quantum logic gates and discuss three families of composite
rotations which can be used to correct off-resonance and pulse length errors.
Although developed and described within the context of NMR quantum computing
these sequences should be applicable to any implementation of quantum
computation.Comment: 6 pages RevTex4 including 4 figures. Will submit to Phys. Rev.
Quantifying infective endocarditis risk in patients with predisposing cardiac conditions
Aims: There are scant comparative data quantifying the risk of infective endocarditis (IE) and associated mortality in individuals with predisposing cardiac conditions. Methods and results: English hospital admissions for conditions associated with increased IE risk were followed for 5 years to quantify subsequent IE admissions. The 5-year risk of IE or dying during an IE admission was calculated for each condition and compared with the entire English population as a control. Infective endocarditis incidence in the English population was 36.2/million/year. In comparison, patients with a previous history of IE had the highest risk of recurrence or dying during an IE admission [odds ratio (OR) 266 and 215, respectively]. These risks were also high in patients with prosthetic valves (OR 70 and 62) and previous valve repair (OR 77 and 60). Patients with congenital valve anomalies (currently considered 'moderate risk') had similar levels of risk (OR 66 and 57) and risks in other 'moderate-risk' conditions were not much lower. Congenital heart conditions (CHCs) repaired with prosthetic material (currently considered 'high risk' for 6 months following surgery) had lower risk than all 'moderate-risk' conditions-even in the first 6 months. Infective endocarditis risk was also significant in patients with cardiovascular implantable electronic devices. Conclusion: These data confirm the high IE risk of patients with a history of previous IE, valve replacement, or repair. However, IE risk in some 'moderate-risk' patients was similar to that of several 'high-risk' conditions and higher than repaired CHC. Guidelines for the risk stratification of conditions predisposing to IE may require re-evaluation
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