17,392 research outputs found
Cognitive node selection and assignment algorithms for weighted cooperative sensing in radar systems
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Endocrine disruption in juvenile roach from English rivers: A preliminary study
Juvenile roach Rutilus rutilus from seven rivers of varying water quality were examined for evidence of endocrine disruption. The majority of roach from five of these rivers had femalelike reproductive ducts. The results suggest that juvenile, rather than adult, fish could be used in studies of endocrine disruption in wild fish populations
Updating grassland fertiliser recommendations: principles and practice
Author's copy of the final published version. Made available by permission of the publisher.Providing fertiliser recommendations for grassland is challenging due to the variety and complexity of livestock production systems ranging from extended grazing to fully housed 'zero grazing' systems. Many farms use multiple grazings and cuttings and there is a wide range of field conditions and grass growth potential. Nutrients recycled at grazing and nitrogen (N) fixed by clover add another layer of complexity and the quantity of grass production is dependent on livestock stocking rates and concentrate use, and can be considerably lower than growth potential. New grassland recommendation systems need to take account of and maximise the impact of recent research findings while also remaining relevant to modern livestock production systems. The challenge is to synthesise research into recommendations that are provided at an appropriate level of precision and area also easy to understand, accessible and recognisable so that farmers can relate them to their own systems. Only then will uptake and use of recommendation increase to further contribute towards improved nutrient use efficiency in grassland production
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Insights into Functionality-Specific Adsorption Dynamics and Stable Reaction Intermediates Using Fast Field Cycling NMR
Fast
field cycling, FFC, NMR relaxometry experiments are reported in the
frequency range of 10 kHz to 40 MHz to characterize the molecular
dynamics of a series of protic (methanol and water) and aprotic (dimethyl
sulfoxide, acetone, cyclohexane, and n-heptane) adsorbates
on a γ-alumina surface of catalytic interest. By analyzing the
data in the T1 domain, two distinct peaks
were observed for both methanol and acetone. In the case of methanol,
the two peaks have been shown to originate from the two chemical environments
of methanol, which at low field strengths differentiate the O1H and alkyl 1H interactions with the surface. In
contrast, the second environment of adsorbed acetone is assigned to
a stable reaction intermediate formed during an aldol reaction, which
strongly influences other molecular adsorption processes at the surface.
Inversion of the FFC-NMR data into the T1-domain enables the combination of the ability of low field NMR to
characterize relaxation modes directly associated with adsorption
with T1 measurements specific to functional
groups and reaction intermediates, thereby avoiding misinterpretation
of molecular adsorption characteristics and giving greater insight
into adsorption and catalytic behavior than is possible from the overall
relaxation dispersion profiles alone
Beyond Patient Reported Pain: Perfusion Magnetic Resonance Imaging Demonstrates Reproducible Cerebral Representation of Ongoing Post-Surgical Pain
This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Monocyte Subset Recruitment Marker Profile Is Inversely Associated With Blood ApoA1 Levels.
Dyslipidemia promotes development of the atherosclerotic plaques that characterise cardiovascular disease. Plaque progression requires the influx of monocytes into the vessel wall, but whether dyslipidemia is associated with an increased potential of monocytes to extravasate is largely unknown. Here (using flow cytometry) we examined recruitment marker expression on monocytes from generally healthy individuals who differed in lipid profile. Comparisons were made between monocyte subsets, participants and relative to participants' lipid levels. Monocyte subsets differed significantly in their expression of recruitment markers, with highest expression being on either the classical or non-classical subsets. However, these inter-subset differences were largely overshadowed by considerable inter-participant differences with some participants having higher levels of recruitment markers on all three monocyte subsets. Furthermore, when the expression of one recruitment marker was high, so too was that of most of the other markers, with substantial correlations evident between the markers. The inter-participant differences were explained by lipid levels. Most notably, there was a significant inverse correlation for most markers with ApoA1 levels. Our results indicate that dyslipidemia, in particular low levels of ApoA1, is associated with an increased potential of all monocyte subsets to extravasate, and to do so using a wider repertoire of recruitment markers than currently appreciated
A dusty pinwheel nebula around the massive star WR 104
Wolf-Rayet (WR) stars are luminous massive blue stars thought to be immediate
precursors to the supernova terminating their brief lives. The existence of
dust shells around such stars has been enigmatic since their discovery some 30
years ago; the intense radiation field from the star should be inimical to dust
survival. Although dust-creation models, including those involving interacting
stellar winds from a companion star, have been put forward, high-resolution
observations are required to understand this phenomena. Here we present
resolved images of the dust outflow around Wolf-Rayet WR 104, obtained with
novel imaging techniques, revealing detail on scales corresponding to about 40
AU at the star. Our maps show that the dust forms a spatially confined stream
following precisely a linear (or Archimedian) spiral trajectory. Images taken
at two separate epochs show a clear rotation with a period of 220 +/- 30 days.
Taken together, these findings prove that a binary star is responsible for the
creation of the circumstellar dust, while the spiral plume makes WR 104 the
prototype of a new class of circumstellar nebulae unique to interacting wind
systems.Comment: 7 pages, 2 figures, Appearing in Nature (1999 April 08
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