Perspectivas de la biología marina

La biología marina es una rama de las ciencias del mar de reciente desarrollo en la Argentina (oceáno Atlántico sudoccidental) que está en franco crecimiento. Se muestra un panorama del desarrollo de las diversas disciplinas, como los estudios sobre la biodiversidad marina y de la biología marina y pesquera, así como amenazas a los ambientes marinos y medidas de conservación tomadas. Se incluyen las perspectivas para futuros estudios de biología marina, los beneficios de las iniciativas de divulgación científica, entre otros temas, así como otras lecturas afines sugeridas

The Landau problem and noncommutative quantum mechanics

The conditions under which noncommutative quantum mechanics and the Landau problem are equivalent theories is explored. If the potential in noncommutative quantum mechanics is chosen as $V= \Omega \aleph$ with $\aleph$ defined in the text, then for the value ${\tilde \theta} = 0.22 \times 10^{-11} cm^2$ (that measures the noncommutative effects of the space), the Landau problem and noncommutative quantum mechanics are equivalent theories in the lowest Landau level. For other systems one can find differents values for ${\tilde \theta}$ and, therefore, the possible bounds for ${\tilde \theta}$ should be searched in a physical independent scenario. This last fact could explain the differents bounds for $\tilde \theta$ found in the literature.Comment: This a rewritten and corrected version of our previous preprint hep-th/010517

Holographic Entropy Packing inside a Black Hole

If general relativity is spontaneously induced, the black hole limit is governed by a phase transition which occurs precisely at the would have been horizon. The exterior Schwarzschild solution then connects with a novel core of vanishing spatial volume. The Kruskal structure, admitting the exact Hawking imaginary time periodicity, is recovered, with the conic defect defused at the origin, rather than at the horizon. The entropy stored inside \textbf{any} interior sphere is universal, equal to a quarter of its surface area, thus locally saturating the 't Hooft-Susskind holographic bound. The associated Komar mass and material energy functions are non-singular.Comment: [V3] accepted to PRL (version shortened, a paragraph on singularity structure added); 10 pages, no figure

Three flavors of extremal Betti tables

We discuss extremal Betti tables of resolutions in three different contexts. We begin over the graded polynomial ring, where extremal Betti tables correspond to pure resolutions. We then contrast this behavior with that of extremal Betti tables over regular local rings and over a bigraded ring.Comment: 20 page

Twist Deformation of Rotationally Invariant Quantum Mechanics

Non-commutative Quantum Mechanics in 3D is investigated in the framework of the abelian Drinfeld twist which deforms a given Hopf algebra while preserving its Hopf algebra structure. Composite operators (of coordinates and momenta) entering the Hamiltonian have to be reinterpreted as primitive elements of a dynamical Lie algebra which could be either finite (for the harmonic oscillator) or infinite (in the general case). The deformed brackets of the deformed angular momenta close the so(3) algebra. On the other hand, undeformed rotationally invariant operators can become, under deformation, anomalous (the anomaly vanishes when the deformation parameter goes to zero). The deformed operators, Taylor-expanded in the deformation parameter, can be selected to minimize the anomaly. We present the deformations (and their anomalies) of undeformed rotationally-invariant operators corresponding to the harmonic oscillator (quadratic potential), the anharmonic oscillator (quartic potential) and the Coulomb potential.Comment: 20 page

Entropy-Area Relations in Field Theory

We consider the contribution to the entropy from fields in the background of a curved time-independent metric. To account for the curvature of space, we postulate a position-dependent UV cutoff. We argue that a UV cutoff on energy naturally implies an IR cutoff on distance. With this procedure, we calculate the scalar contribution in a background anti-de Sitter space, the exterior of a black hole, and de Sitter space. In all cases, we find results that can be simply interpreted in terms of local energy and proper volume, yielding insight into the apparent reduced dimensionality of systems with gravity.Comment: 20 pages, 1 figur

On the Differential Geometry of GLq(1∣1)GL_q(1| 1)

The differential calculus on the quantum supergroup GL$_q(1| 1)$ was introduced by Schmidke {\it et al}. (1990 {\it Z. Phys. C} {\bf 48} 249). We construct a differential calculus on the quantum supergroup GL$_q(1| 1)$ in a different way and we obtain its quantum superalgebra. The main structures are derived without an R-matrix. It is seen that the found results can be written with help of a matrix $\hat{R}$Comment: 14 page

The QCD Membrane

In this paper we study spatially quenched, SU(N) Yang-Mills theory in the large-N limit. The resulting reduced action shows the same formal look as the Banks-Fischler-Shenker-Susskind M-theory action. The Weyl-Wigner-Moyal symbol of this matrix model is the Moyal deformation of a p(=2)-brane action. Thus, the large-N limit of the spatially quenched SU(N) Yang-Mills is seen to describe a dynamical membrane. By assuming spherical symmetry we compute the mass spectrum of this object in the WKB approximation.Comment: 14 pages, LaTeX, non figures; accepted for publication in Class.Quant. Gra

Quality of Life in Partners of Young and Old Breast Cancer Survivors

Background: Partners of breast cancer survivors experience the effects of a spouse's cancer years after treatment. Partners of younger survivors (YP) may experience greater problems than partners of older survivors (OP), just as younger survivors experience greater problems than their older counterparts. Objectives: To 1) compare quality of life (QoL) in YP and OP, and 2) determine contributing factors to each group's QoL. Methods: Cross-sectional data were collected from YP (n=227) and OP (n=281) through self-report. MANOVA was used to determine differences between YP and OP on QoL while controlling for covariates. Multiple regression analyses were conducted to determine what contributes to each group's QoL. Results: YP reported better physical function (effect size (ES)= -0.57), lower marital satisfaction (ES=0.39), and lower overall QoL (ES=0.43) than partners of older survivors. Predictors of QoL also differed between partner groups. For YP, overall QoL was predicted by greater physical functioning, fewer depressive symptoms, higher marital satisfaction, higher parenting satisfaction, and more personal resources. R2= .47; F(5, 195)= 35.05; p<.001. For OP, overall QoL was predicted by fewer depressive symptoms, higher parenting satisfaction, higher spirituality, and greater social support from the breast cancer survivor spouse. R2= .33; F(4, 244)= 29.80; p<.001. Conclusions: OP reported greater QoL than YP. Common factors contributing to QoL between YP and OP were fewer depressive symptoms and higher parenting satisfaction. Implications for Practice: Partners of breast cancer survivors may need support coping with their spouse’s/partner’s cancer. Partners of younger survivors may require more support than partners of older survivors.This study was coordinated by the ECOG-ACRIN Cancer Research Group (Robert L. Comis, MD and Mitchell D. Schnall, MD, PhD, Group Co-Chairs) and supported in part by Public Health Service Grants CA189828, CA180795, CA37403, CA35199, CA17145 and CA49883, and from the National Cancer Institute, National Institutes of Health and the Department of Health and Human Services. Its content is solely the responsibility of the authors and does not necessarily represent the official views of the National Cancer Institute. Research reported in this publication was supported by the National Cancer Institute of the National Institutes of Health under Award Numbers K05CA175048, T32CA117865-11, and R25CA117865. Its content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health, including the National Cancer Institute or the National Institute of Nursing Research

Holographic multiverse and the measure problem

We discuss the duality, conjectured in earlier work, between the wave function of the multiverse and a 3D Euclidean theory on the future boundary of spacetime. In particular, we discuss the choice of the boundary metric and the relation between the UV cutoff scale xi on the boundary and the hypersurfaces Sigma on which the wave function is defined in the bulk. We propose that in the limit of xi going to 0 these hypersurfaces should be used as cutoff surfaces in the multiverse measure. Furthermore, we argue that in the inflating regions of spacetime with a slowly varying Hubble rate H the hypersurfaces Sigma are surfaces of constant comoving apparent horizon (CAH). Finally, we introduce a measure prescription (called CAH+) which appears to have no pathological features and coincides with the constant CAH cutoff in regions of slowly varying H.Comment: A minor change: the discussion of unitarity on p.9 is clarifie