2,318 research outputs found
A study of electric motors for use in liquid and gaseous helium Engineering report no. 3530
Electric motor design and operation in liquid and gaseous helium environment
A new species of Prosorhynchoides (Trematoda, Bucephalidae) from the intertidal rocky zone of central Chile
A new bucephalid species, Prosorhynchoides carvajali sp. nov. is described. This parasite was found in three marine fish, Auchenionchus microcirrhis (type-host), A. variolosus and Sicyases sanguineus (other-hosts), collected from the intertidal rocky zones of central Chile. P. carvajali sp. nov. is characterized by a pharynx in a post-equatorial position, a large cirrus sac length (half of the total worm length) and rounded caecum extending dorsally and anteriorly from pharynx. Although Prosorhynchoides carvajali sp. nov. closely resembles P. labiata; the latter has an elongated, narrow and inverted-U-shape caecum, contrasting to P. carvajali sp. nov. which has a larger rounded caecum, directed anteriorly. To our knowledge this is the first known report of Prosorhynchoides on the South American Pacific coast
Proton imaging of stochastic magnetic fields
Recent laser-plasma experiments report the existence of dynamically
significant magnetic fields, whose statistical characterisation is essential
for understanding the physical processes these experiments are attempting to
investigate. In this paper, we show how a proton imaging diagnostic can be used
to determine a range of relevant magnetic field statistics, including the
magnetic-energy spectrum. To achieve this goal, we explore the properties of an
analytic relation between a stochastic magnetic field and the image-flux
distribution created upon imaging that field. We conclude that features of the
beam's final image-flux distribution often display a universal character
determined by a single, field-scale dependent parameter - the contrast
parameter - which quantifies the relative size of the correlation length of the
stochastic field, proton displacements due to magnetic deflections, and the
image magnification. For stochastic magnetic fields, we establish the existence
of four contrast regimes - linear, nonlinear injective, caustic and diffusive -
under which proton-flux images relate to their parent fields in a qualitatively
distinct manner. As a consequence, it is demonstrated that in the linear or
nonlinear injective regimes, the path-integrated magnetic field experienced by
the beam can be extracted uniquely, as can the magnetic-energy spectrum under a
further statistical assumption of isotropy. This is no longer the case in the
caustic or diffusive regimes. We also discuss complications to the
contrast-regime characterisation arising for inhomogeneous, multi-scale
stochastic fields, as well as limitations currently placed by experimental
capabilities on extracting magnetic field statistics. The results presented in
this paper provide a comprehensive description of proton images of stochastic
magnetic fields, with applications for improved analysis of given proton-flux
images.Comment: Main paper pp. 1-29; appendices pp. 30-84. 24 figures, 2 table
Embeddings from the point of view of immersion theory: Part II
Let M and N be smooth manifolds. For an open V of M let emb(V,N) be the space
of embeddings from V to N. By results of Goodwillie and Goodwillie-Klein, the
cofunctor V |--> emb(V,N) is analytic if dim(N)-dim(M) > 2. We deduce that its
Taylor series converges to it. For details about the Taylor series, see Part I.Comment: 16 pages. Published copy, also available at
http://www.maths.warwick.ac.uk/gt/GTVol3/paper4.abs.htm
Three-manifold invariant from functional integration
We give a precise definition and produce a path-integral computation of the
normalized partition function of the abelian U(1) Chern-Simons field theory
defined in a general closed oriented 3-manifold. We use the Deligne-Beilinson
formalism, we sum over the inequivalent U(1) principal bundles over the
manifold and, for each bundle, we integrate over the gauge orbits of the
associated connection 1- forms. The result of the functional integration is
compared with the abelian U(1) Reshetikhin-Turaev surgery invariant
Equivariant cohomology over Lie groupoids and Lie-Rinehart algebras
Using the language and terminology of relative homological algebra, in
particular that of derived functors, we introduce equivariant cohomology over a
general Lie-Rinehart algebra and equivariant de Rham cohomology over a locally
trivial Lie groupoid in terms of suitably defined monads (also known as
triples) and the associated standard constructions. This extends a
characterization of equivariant de Rham cohomology in terms of derived functors
developed earlier for the special case where the Lie groupoid is an ordinary
Lie group, viewed as a Lie groupoid with a single object; in that theory over a
Lie group, the ordinary Bott-Dupont-Shulman-Stasheff complex arises as an a
posteriori object. We prove that, given a locally trivial Lie groupoid G and a
smooth G-manifold f over the space B of objects of G, the resulting
G-equivariant de Rham theory of f boils down to the ordinary equivariant de
Rham theory of a vertex manifold relative to the corresponding vertex group,
for any vertex in the space B of objects of G; this implies that the
equivariant de Rham cohomology introduced here coincides with the stack de Rham
cohomology of the associated transformation groupoid whence this stack de Rham
cohomology can be characterized as a relative derived functor. We introduce a
notion of cone on a Lie-Rinehart algebra and in particular that of cone on a
Lie algebroid. This cone is an indispensable tool for the description of the
requisite monads.Comment: 47 page
Chalcone-based Selective Inhibitors of a C4 Plant Key Enzyme as Novel Potential Herbicides
Weeds are a challenge for global food production due to their rapidly evolving resistance against herbicides. We have identified chalcones as selective inhibitors of phosphoenolpyruvate carboxylase (PEPC), a key enzyme for carbon fixation and biomass increase in the C4 photosynthetic pathway of many of the world’s most damaging weeds. In contrast, many of the most important crop plants use C3 photosynthesis. Here, we show that 2′,3′,4′,3,4-Pentahydroxychalcone (IC50 = 600 nM) and 2′,3′,4′-Trihydroxychalcone (IC50 = 4.2 μM) are potent inhibitors of C4 PEPC but do not affect C3 PEPC at a same concentration range (selectivity factor: 15–45). Binding and modeling studies indicate that the active compounds bind at the same site as malate/aspartate, the natural feedback inhibitors of the C4 pathway. At the whole plant level, both substances showed pronounced growth-inhibitory effects on the C4 weed Amaranthus retroflexus, while there were no measurable effects on oilseed rape, a C3 plant. Growth of selected soil bacteria was not affected by these substances. Our chalcone compounds are the most potent and selective C4 PEPC inhibitors known to date. They offer a novel approach to combat C4 weeds based on a hitherto unexplored mode of allosteric inhibition of a C4 plant key enzyme
Sensor‐mediated granular sludge reactor for nitrogen removal and reduced aeration demand using a dilute wastewater
A sensor‐mediated strategy was applied to a laboratory‐scale granular sludge reactor (GSR) to demonstrate that energy‐efficient inorganic nitrogen removal is possible with a dilute mainstream wastewater. The GSR was fed a dilute wastewater designed to simulate an A‐stage mainstream anaerobic treatment process. DO, pH, and ammonia/nitrate sensors measured water quality as part of a real‐time control strategy that resulted in low‐energy nitrogen removal. At a low COD (0.2 kg m−3 day−1) and ammonia (0.1 kg‐N m−3 day−1) load, the average degree of ammonia oxidation was 86.2 ± 3.2% and total inorganic nitrogen removal was 56.7 ± 2.9% over the entire reactor operation. Aeration was controlled using a DO setpoint, with and without residual ammonia control. Under both strategies, maintaining a low bulk oxygen level (0.5 mg/L) and alternating aerobic/anoxic cycles resulted in a higher level of nitrite accumulation and supported shortcut inorganic nitrogen removal by suppressing nitrite oxidizing bacteria. Furthermore, coupling a DO setpoint aeration strategy with residual ammonia control resulted in more stable nitritation and improved aeration efficiency. The results show that sensor‐mediated controls, especially coupled with a DO setpoint and residual ammonia controls, are beneficial for maintaining stable aerobic granular sludge.Practitioner pointsTight sensor‐mediated aeration control is need for better PN/A.Low DO intermittent aeration with minimum ammonium residual results in a stable N removal.Low DO aeration results in a stable NOB suppression.Using sensor‐mediated aeration control in a granular sludge reactor reduces aeration cost.Multiple metabolic pathways and competition for nitrite exist in the treatment of anaerobically pretreated mainstream wastewater using a granular sludge reactor.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/155879/1/wer1296_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/155879/2/wer1296.pd
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