1,258 research outputs found
Experimental investigation of the flow evolution in the tributary of a 90° open channel confluence
Open channel and river confluences have received a lot of attention in hydraulic literature, because of the interesting flow phenomena observed. Features such as flow acceleration, curvature, separation, mixing and recovery are combined in the confluence area into a complex 3D flow pattern. Typically, the analysis of these features is started at the upstream corner of the confluence area, and the upstream main and tributary branches are considered to be the (uniform) upstream boundary conditions. However, several indications in literature suggest the existence of flow features upstream of the confluence corner. This paper confirms, by means of measurements in a laboratory, 90° confluence flume, considerable streamline curvature in the tributary branch, upstream of the confluence. Furthermore, it shows and quantifies velocity redistribution as well as local water surface super-elevation and depression in the tributary branch. Consequently, flow fea-ture analysis in confluences should start a considerable distance upstream of the confluence
Topological Gauge Theory Of General Weitzenbock Manifolds Of Dislocations In Crystals
General Weitzenbock material manifolds of dislocations in crystals Are
proposed, the reference, idealized and deformation states of the bodies in
general case are generally described by the general manifolds, the topological
gauge field theory of dislocations is given in general case,true distributions
and evolution of dislocations in crystals are given by the formulas describing
dislocations in terms of the general manifolds,furthermore, their properties
are discussed.Comment: 10pages, Revte
Risk factors for recurrent C lostridium difficile infection in hematopoietic stem cell transplant recipients
Background Recurrent C lostridium difficile infection ( CDI ) represents a significant burden on the healthcare system and is associated with poor outcomes in hematopoietic stem cell transplant ( HSCT ) patients. Data are limited evaluating recurrence rates and risk factors for recurrence in HSCT patients. Methods HSCT patients who developed CDI between January 2010 and December 2012 were divided into 2 groups: nonârecurrent CDI (nr CDI ) and recurrent CDI ( rCDI ). Risk factors for rCDI were compared between groups. Rate of recurrence in HSCT patients was compared to that in other hospitalized patients. Results CDI was diagnosed in 95 of 711 HSCT patients (22 rCDI and 73 nr CDI ). Recurrence rates were similar in HSCT patients compared with other hospitalized patients (23.2% vs. 22.9%, P Â >Â 0.99). Patients in the rCDI group developed the index case of CDI significantly earlier than the nr CDI group (3.5Â days vs. 7.0Â days after transplant, P Â =Â 0.05). On univariate analysis, patients with rCDI were more likely to have prior history of CDI and neutropenia at the time of the index CDI case. Neutropenia at the time of the index CDI case was the only independent predictor of rCDI (78.8 vs. 34.8%, P Â =Â 0.006) on multivariate analysis. Conclusions The rate of rCDI was similar between HSCT and other hospitalized patients, and the majority of patients developed the index case of CDI within a week of transplantation. Neutropenia at the index CDI case may be associated with increased rates of rCDI .Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/109272/1/tid12267.pd
Determining 3-D Motion and Structure of a Rigid Body Using the Spherical Projection
Coordinated Science Laboratory was formerly known as Control Systems LaboratoryNational Science Foundation / NSF ECS 81-1208
Twist-3 Distribute Amplitude of the Pion in QCD Sum Rules
We apply the background field method to calculate the moments of the pion
two-particles twist-3 distribution amplitude (DA) in QCD sum
rules. In this paper,we do not use the equation of motion for the quarks inside
the pion since they are not on shell and introduce a new parameter to
be determined. We get the parameter in this approach. If
assuming the expansion of in the series in Gegenbauer polynomials
, one can obtain its approximate expression which can be
determined by its first few moments.Comment: 12 pages, 3 figure
Generalized twisted modules associated to general automorphisms of a vertex operator algebra
We introduce a notion of strongly C^{\times}-graded, or equivalently,
C/Z-graded generalized g-twisted V-module associated to an automorphism g, not
necessarily of finite order, of a vertex operator algebra. We also introduce a
notion of strongly C-graded generalized g-twisted V-module if V admits an
additional C-grading compatible with g. Let V=\coprod_{n\in \Z}V_{(n)} be a
vertex operator algebra such that V_{(0)}=\C\one and V_{(n)}=0 for n<0 and let
u be an element of V of weight 1 such that L(1)u=0. Then the exponential of
2\pi \sqrt{-1} Res_{x} Y(u, x) is an automorphism g_{u} of V. In this case, a
strongly C-graded generalized g_{u}-twisted V-module is constructed from a
strongly C-graded generalized V-module with a compatible action of g_{u} by
modifying the vertex operator map for the generalized V-module using the
exponential of the negative-power part of the vertex operator Y(u, x). In
particular, we give examples of such generalized twisted modules associated to
the exponentials of some screening operators on certain vertex operator
algebras related to the triplet W-algebras. An important feature is that we
have to work with generalized (twisted) V-modules which are doubly graded by
the group C/Z or C and by generalized eigenspaces (not just eigenspaces) for
L(0), and the twisted vertex operators in general involve the logarithm of the
formal variable.Comment: Final version to appear in Comm. Math. Phys. 38 pages. References on
triplet W-algebras added, misprints corrected, and expositions revise
Analysis of and with QCD sum rules
In this article, we calculate the masses and the pole residues of the
heavy baryons and with the QCD
sum rules. The numerical values (or
) and (or ) are in good agreement
with the experimental data.Comment: 18 pages, 18 figures, slight revisio
On almost distance-regular graphs
Distance-regular graphs are a key concept in Algebraic Combinatorics and have
given rise to several generalizations, such as association schemes. Motivated
by spectral and other algebraic characterizations of distance-regular graphs,
we study `almost distance-regular graphs'. We use this name informally for
graphs that share some regularity properties that are related to distance in
the graph. For example, a known characterization of a distance-regular graph is
the invariance of the number of walks of given length between vertices at a
given distance, while a graph is called walk-regular if the number of closed
walks of given length rooted at any given vertex is a constant. One of the
concepts studied here is a generalization of both distance-regularity and
walk-regularity called -walk-regularity. Another studied concept is that of
-partial distance-regularity or, informally, distance-regularity up to
distance . Using eigenvalues of graphs and the predistance polynomials, we
discuss and relate these and other concepts of almost distance-regularity, such
as their common generalization of -walk-regularity. We introduce the
concepts of punctual distance-regularity and punctual walk-regularity as a
fundament upon which almost distance-regular graphs are built. We provide
examples that are mostly taken from the Foster census, a collection of
symmetric cubic graphs. Two problems are posed that are related to the question
of when almost distance-regular becomes whole distance-regular. We also give
several characterizations of punctually distance-regular graphs that are
generalizations of the spectral excess theorem
Proteomic profiling of proteins associated with the rejuvenation of Sequoia sempervirens (D. Don) Endl
Background: Restoration of rooting competence is important for rejuvenation in Sequoia sempervirens (D. Don) Endl and is achieved by repeatedly grafting Sequoia shoots after 16 and 30 years of cultivation in vitro. Results: Mass spectrometry-based proteomic analysis revealed three proteins that differentially accumulated in different rejuvenation stages, including oxygen-evolving enhancer protein 2 (OEE2), glycine-rich RNA-binding protein (RNP), and a thaumatin-like protein. OEE2 was found to be phosphorylated and a phosphopeptide (YEDNFDGNSNVSVMVpTPpTDK) was identified. Specifically, the protein levels of OEE2 increased as a result of grafting and displayed a higher abundance in plants during the juvenile and rejuvenated stages. Additionally, SsOEE2 displayed the highest expression levels in Sequoia shoots during the juvenile stage and less expression during the adult stage. The expression levels also steadily increased during grafting. Conclusion: Our results indicate a positive correlation between the gene and protein expression patterns of SsOEE2 and the rejuvenation process, suggesting that this gene is involved in the rejuvenation of Sequoia sempervirens
Semileptonic Bs ->DsJ(2460)l nu decay in QCD
Using three point QCD sum rules method, the form factors relevant to the
semileptonic Bs ->DsJ (2460)l nu decay are calculated. The q2 dependence of
these form factors is evaluated and compared with the heavy quark effective
theory predictions. The dependence of the asymmetry parameter alpha,
characterizing the polarization of DsJ meson, on q2 is studied .The branching
ratio of this decay is also estimated and is shown that it can be easily
detected at LHC.Comment: 21 pages, 5 figures and 1 Tabl
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