Alternative symplectic structures for SO(3,1) and SO(4) four-dimensional BF theories

The most general action, quadratic in the B fields as well as in the curvature F, having SO(3,1) or SO(4) as the internal gauge group for a four-dimensional BF theory is presented and its symplectic geometry is displayed. It is shown that the space of solutions to the equations of motion for the BF theory can be endowed with symplectic structures alternative to the usual one. The analysis also includes topological terms and cosmological constant. The implications of this fact for gravity are briefly discussed.Comment: 13 pages, LaTeX file, no figure

Strong subdifferentiability of norms and geometry of Banach spaces

summary:The strong subdifferentiability of norms (i.e\. one-sided differentiability uniform in directions) is studied in connection with some structural properties of Banach spaces. It is shown that every separable Banach space with nonseparable dual admits a norm that is nowhere strongly subdifferentiable except at the origin. On the other hand, every Banach space with a strongly subdifferentiable norm is Asplund

Weakly Compact Generating and Shrinking Markusevic Bases

2000 Mathematics Subject Classification: 46B30, 46B03.It is shown that most of the well known classes of nonseparable Banach spaces related to the weakly compact generating can be characterized by elementary properties of the closure of the coefficient space of Markusevic bases for such spaces. In some cases, such property is then shared by all Markusevic bases in the space

Accrual financial reporting in the public sector: Is it a reality?

Although modernization of governmental accounting has led to the implementation of accrual financial reporting, budgets in most continental european countries, including spain, continue to be based on cash or modified cash methods. Consequently, cash-based and accrual- based financial information coexist. this may create problems for the full implementation of accrual financial statements. this paper analyzes the differences in practice between the results disclosed in financial and budgetary statements under both bases of accounting in order to identify to what extent accrual accounting has been implemented and to verify whether budgetary and accrual- based financial figures are significantly different. the research findings show that there is a high correlation between the current budgetary result and the economic result and, therefore, that in practice the accrual principle has not been implemented effectively

Accrual financial reporting in the public sector: Is it a reality?

Although modernization of governmental accounting has led to the implementation of accrual financial reporting, budgets in most continental european countries, including spain, continue to be based on cash or modified cash methods. Consequently, cash-based and accrual- based financial information coexist. this may create problems for the full implementation of accrual financial statements. this paper analyzes the differences in practice between the results disclosed in financial and budgetary statements under both bases of accounting in order to identify to what extent accrual accounting has been implemented and to verify whether budgetary and accrual- based financial figures are significantly different. the research findings show that there is a high correlation between the current budgetary result and the economic result and, therefore, that in practice the accrual principle has not been implemented effectively

The numerical index of 22-dimensional Lipschitz-free spaces

We provide the explicit formula for the numerical index of any $2$-dimensional Lipschitz-free space, also giving the construction of operators attaining this value as its numerical radius. As a consequence, the numerical index of $2$-dimensional Lipschitz-free spaces can take any value of the interval $[\frac{1}{2},1]$, and this whole range of numerical indices can be attained by taking $2$-dimensional subspaces of any Lipschitz-free space of the form $\mathcal{F}(A)$, where $A\subset {\mathbb{R}}^n$ with $n\geq 2$ is any set with non-empty interior

Evidence for a circumplanetary disk around protoplanet PDS 70 b

We present the first observational evidence for a circumplanetary disk around the protoplanet PDS~70~b, based on a new spectrum in the $K$ band acquired with VLT/SINFONI. We tested three hypotheses to explain the spectrum: Atmospheric emission from the planet with either (1) a single value of extinction or (2) variable extinction, and (3) a combined atmospheric and circumplanetary disk model. Goodness-of-fit indicators favour the third option, suggesting circumplanetary material contributing excess thermal emission --- most prominent at $\lambda \gtrsim 2.3 \mu$m. Inferred accretion rates ($\sim 10^{-7.8}$--$10^{-7.3} M_J$ yr$^{-1}$) are compatible with observational constraints based on the H$\alpha$ and Br$\gamma$ lines. For the planet, we derive an effective temperature of 1500--1600 K, surface gravity $\log(g)\sim 4.0$, radius $\sim 1.6 R_J$, mass $\sim 10 M_J$, and possible thick clouds. Models with variable extinction lead to slightly worse fits. However, the amplitude ($\Delta A_V \gtrsim 3$mag) and timescale of variation ($\lesssim$~years) required for the extinction would also suggest circumplanetary material.Comment: 8 pages, 2 figures, 1 table. This is a pre-copyedited, author-produced PDF of an article accepted for publication in ApJL on 2019 May 1

Dynamical stabilization of matter-wave solitons revisited

We consider dynamical stabilization of Bose-Einstein condensates (BEC) by time-dependent modulation of the scattering length. The problem has been studied before by several methods: Gaussian variational approximation, the method of moments, method of modulated Townes soliton, and the direct averaging of the Gross-Pitaevskii (GP) equation. We summarize these methods and find that the numerically obtained stabilized solution has different configuration than that assumed by the theoretical methods (in particular a phase of the wavefunction is not quadratic with $r$). We show that there is presently no clear evidence for stabilization in a strict sense, because in the numerical experiments only metastable (slowly decaying) solutions have been obtained. In other words, neither numerical nor mathematical evidence for a new kind of soliton solutions have been revealed so far. The existence of the metastable solutions is nevertheless an interesting and complicated phenomenon on its own. We try some non-Gaussian variational trial functions to obtain better predictions for the critical nonlinearity $g_{cr}$ for metastabilization but other dynamical properties of the solutions remain difficult to predict

Weakly uniformly rotund Banach spaces

summary:The dual space of a WUR Banach space is weakly K-analytic

Disk Radii and Grain Sizes in Herschel-Resolved Debris Disks

(Abridged) The radii of debris disks and the sizes of their dust grains are tracers of the formation mechanisms and physical processes operating in these systems. We use a sample of 34 debris disks spatially resolved in various Herschel programs to constrain them. While we modeled disks with both warm and cold components, we focus our analysis only on the cold outer disks, i.e. Kuiper-belt analogs. The disk radii derived from the resolved images reveal a large dispersion, but no significant trend with the stellar luminosity, which argues against ice lines as a dominant player in setting the debris disk sizes. Fixing the disk radii to those inferred from the resolved images, we model the spectral energy distributions to determine the dust temperatures and the grain size distributions. While the dust temperature systematically increases towards earlier spectral types, its ratio to the blackbody temperature at the disk radius decreases with the stellar luminosity. This is explained by an increase of typical grain sizes towards more luminous stars. The sizes are compared to the radiation pressure blowout limit $s_\text{blow}$ that is proportional to the stellar luminosity-to-mass ratio and thus also increases towards earlier spectral classes. The grain sizes in the disks of G- to A-stars are inferred to be several times $s_\text{blow}$ at all stellar luminosities, in agreement with collisional models of debris disks. The sizes, measured in the units of $s_\text{blow}$, appear to decrease with the luminosity, which may be suggestive of the disk's stirring level increasing towards earlier-type stars.Comment: accepted for publication in ApJ, 22 pages, 7 figure