7,399 research outputs found
On the inertia of heat
Does heat have inertia? This question is at the core of a long-standing
controversy on Eckart's dissipative relativistic hydrodynamics. Here I show
that the troublesome inertial term in Eckart's heat flux arises only if one
insists on defining thermal diffusivity as a spacetime constant. I argue that
this is the most natural definition, and that all confusion disappears if one
considers instead the space-dependent comoving diffusivity, in line with the
fact that, in the presence of gravity, space is an inhomogeneous medium.Comment: 3 page
Interaction energy functional for lattice density functional theory: Applications to one-, two- and three-dimensional Hubbard models
The Hubbard model is investigated in the framework of lattice density
functional theory (LDFT). The single-particle density matrix with
respect the lattice sites is considered as the basic variable of the many-body
problem. A new approximation to the interaction-energy functional
is proposed which is based on its scaling properties and which recovers exactly
the limit of strong electron correlations at half-band filling. In this way, a
more accurate description of is obtained throughout the domain of
representability of , including the crossover from weak to strong
correlations. As examples of applications results are given for the
ground-state energy, charge-excitation gap, and charge susceptibility of the
Hubbard model in one-, two-, and three-dimensional lattices. The performance of
the method is demonstrated by comparison with available exact solutions, with
numerical calculations, and with LDFT using a simpler dimer ansatz for .
Goals and limitations of the different approximations are discussed.Comment: 25 pages and 8 figures, submitted to Phys. Rev.
Does bariatric surgery improve adipose tissue function?
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134250/1/obr12429_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134250/2/obr12429.pd
Clasificación Histopatológica de Linfomas Caninos en la Casuística del Laboratorio de Patología Veterinaria de la Universidad Nacional Mayor de San Marcos (1996-2012)
The aim of this study was to apply the criteria of the World Health Organization (WHO) in the histopathological classification of canine lymphoma on cases diagnosed from 1996 to 2012 at the veterinary pathology laboratory of San Marcos University, Lima, Peru. A total of 1778 reports of canine neoplasia were revised and 16 cases with histopathological diagnoses of canine lymphoma were studied. The following types of lymphoma were identified: diffuse large B cell lymphoma (7/16) (immunoblastic subtype [4/16], centroblastic subtype [2/16], rich subtype T cells [1/16]), mantle cell lymphoma (3/ 16), peripheral T-cell lymphoma not otherwise specified (2/16), precursor B/T lymphoblastic lymphoma (2/16), anaplastic large cell lymphoma (1/16) and mycosis fungoides (1/16).El presente estudio tuvo como objetivo emplear los criterios de la Organización Mundial de la Salud (OMS) en la clasificación histopatológica del linfoma canino en los casos diagnosticados en el laboratorio de patología veterinaria de la Universidad Nacional Mayor de San Marcos, Lima, Perú, entre 1996 y 2012. Se revisaron 1778 informes con diagnóstico histopatológico de neoplasias caninas y se encontraron 16 casos con diagnóstico histopatológico de linfoma canino. Se identificaron los siguientes tipos de linfomas: Linfoma difuso de células grandes B (7/16) (subtipo inmunoblástico [4/16], subtipo centroblástico [2/16], subtipo rico en células T [1/16]), linfoma de células del manto (3/16), linfoma T periférico inespecífico (2/16), linfoma linfoblástico de células precursoras B/T (2/16), linfoma anaplásico de células grandes (1/16) y micosis fungoides (1/16)
Anomalous Lattice Vibrations of Single and Few-Layer MoS2
Molybdenum disulfide (MoS2) of single and few-layer thickness was exfoliated
on SiO2/Si substrate and characterized by Raman spectroscopy. The number of
S-Mo-S layers of the samples was independently determined by contact-mode
atomic-force microscopy. Two Raman modes, E12g and A1g, exhibited sensitive
thickness dependence, with the frequency of the former decreasing and that of
the latter increasing with thickness. The results provide a convenient and
reliable means for determining layer thickness with atomic-level precision. The
opposite direction of the frequency shifts, which cannot be explained solely by
van der Waals interlayer coupling, is attributed to Coulombic interactions and
possible stacking-induced changes of the intralayer bonding. This work
exemplifies the evolution of structural parameters in layered materials in
changing from the 3-dimensional to the 2-dimensional regime.Comment: 14 pages, 4 figure
Genera of phytopathogenic fungi: GOPHY 3
This paper represents the third contribution in the Genera of Phytopathogenic Fungi (GOPHY) series. The series provides morphological descriptions, information about the pathology, distribution, hosts and disease symptoms for the treated genera, as well as primary and secondary DNA barcodes for the currently accepted species included in these. This third paper in the GOPHY series treats 21 genera of phytopathogenic fungi and their relatives including: Allophoma, Alternaria, Brunneosphaerella, Elsinoe, Exserohilum, Neosetophoma, Neostagonospora, Nothophoma, Parastagonospora, Phaeosphaeriopsis, Pleiocarpon, Pyrenophora, Ramichloridium, Seifertia, Seiridium, Septoriella, Setophoma, Stagonosporopsis, Stemphylium, Tubakia and Zasmidium. This study includes three new genera, 42 new species, 23 new combinations, four new names, and three typifications of older names
Batería III Woodcock-Muñoz
Comentario a cargo de la Prof. Ps. Graciela ArdoinoDepartamento de Ciencias Cognitivas y de la Salud.Facultad de Psicología.Universidad Católica del Urugua
Оценка эффективности управления деятельностью предприятия
Целью исследования является оценка эффективности управления деятельностью предприятия как интегрального показателя, то есть управления совокупностью деятельностей, таких как производственная, инвестиционная, инновационная, маркетинговая и финансовая
Impact of methodology and the use of allometric scaling on the echocardiographic assessment of the aortic root and arch: a study by the Research and Audit Sub-Committee of the British Society of Echocardiography.
The aim of the study is to establish the impact of 2D echocardiographic methods on absolute values for aortic root dimensions and to describe any allometric relationship to body size. We adopted a nationwide cross-sectional prospective multicentre design using images obtained from studies utilising control groups or where specific normality was being assessed. A total of 248 participants were enrolled with no history of cardiovascular disease, diabetes, hypertension or abnormal findings on echocardiography. Aortic root dimensions were measured at the annulus, the sinus of Valsalva, the sinotubular junction, the proximal ascending aorta and the aortic arch using the inner edge and leading edge methods in both diastole and systole by 2D echocardiography. All dimensions were scaled allometrically to body surface area (BSA), height and pulmonary artery diameter. For all parameters with the exception of the aortic annulus, dimensions were significantly larger in systole (P<0.05). All aortic root and arch measurements were significantly larger when measured using the leading edge method compared with the inner edge method (P<0.05). Allometric scaling provided a b exponent of BSA(0.6) in order to achieve size independence. Similarly, ratio scaling to height in subjects under the age of 40 years also produced size independence. In conclusion, the largest aortic dimensions occur in systole while using the leading edge method. Reproducibility of measurement, however, is better when assessing aortic dimensions in diastole. There is an allometric relationship to BSA and, therefore, allometric scaling in the order of BSA(0.6) provides a size-independent index that is not influenced by the age or gender
Density-matrix functional theory of the Hubbard model: An exact numerical study
A density functional theory for many-body lattice models is considered in
which the single-particle density matrix is the basic variable. Eigenvalue
equations are derived for solving Levy's constrained search of the interaction
energy functional W, which is expressed as the sum of Hartree-Fock energy and
the correlation energy E_C. Exact results are obtained for E_C of the Hubbard
model on various periodic lattices. The functional dependence of E_C is
analyzed by varying the number of sites, band filling and lattice structure.
The infinite one-dimensional chain and one-, two-, or three-dimensional finite
clusters with periodic boundary conditions are considered. The properties of
E_C are discussed in the limits of weak and strong electronic correlations, as
well as in the crossover region. Using an appropriate scaling we observe a
pseudo-universal behavior which suggests that the correlation energy of
extended systems could be obtained quite accurately from finite cluster
calculations. Finally, the behavior of E_C for repulsive (U>0) and attractive
(U<0) interactions are contrasted.Comment: Phys. Rev. B (1999), in pres
- …