The Restriction Principle and Commuting Families of Toeplitz Operators on the Unit Ball

On the unit ball B^n we consider the weighted Bergman spaces H_\lambda and their Toeplitz operators with bounded symbols. It is known from our previous work that if a closed subgroup H of \widetilde{\SU(n,1)} has a multiplicity-free restriction for the holomorphic discrete series of \widetilde{\SU(n,1)}, then the family of Toeplitz operators with H-invariant symbols pairwise commute. In this work we consider the case of maximal abelian subgroups of \widetilde{\SU(n,1)} and provide a detailed proof of the pairwise commutativity of the corresponding Toeplitz operators. To achieve this we explicitly develop the restriction principle for each (conjugacy class of) maximal abelian subgroup and obtain the corresponding Segal-Bargmann transform. In particular, we obtain a multiplicity one result for the restriction of the holomorphic discrete series to all maximal abelian subgroups. We also observe that the Segal-Bargman transform is (up to a unitary transformation) a convolution operator against a function that we write down explicitly for each case. This can be used to obtain the explicit simultaneous diagonalization of Toeplitz operators whose symbols are invariant by one of these maximal abelian subgroups

Vanishing Cosmological Constant in Modified Gauss-Bonnet Gravity with Conformal Anomaly

We consider dark energy cosmology in a de Sitter universe filled with quantum conformal matter. Our model represents a Gauss-Bonnet model of gravity with contributions from quantum effects. To the General Relativity action an arbitrary function of the GB invariant, f(G), is added, and taking into account quantum effects from matter the cosmological constant is studied. For the considered model the conditions for a vanishing cosmological constant are considered. Creation of a de Sitter universe by quantum effects in a GB modified gravity is discussed.Comment: 8 pages latex, 1 figure. To appear in Int. J. Mod. Phys.

Modelos de eficiencia económica: El transporte ferroviario

En este estudio se realiza una aplicación empírica de los modelos de eficiencia económica tradicionalmente utilizados. Se desarrolla una exposición comparativa de los siguientes modelos de eficiencia económica: Análisis de Envoltura de Datos (DEA), Método de Mínimos Cuadrados Ordinarios Corregidos (COLS), Análisis Estocástico de Frontera (SFA). En el caso particular del transporte ferroviario en Bolivia, se recomienda el uso de la combinación de los resultados de los modelos DEA y COLS, debido a que se encontró que las funciones de costos –por ejemplo los costos de mantenimientode este tipo de servicio son inflexibles ante perturbaciones estocásticas. Finalmente, se debe resaltar algunas de las limitaciones en la aplicación empírica de los modelos de eficiencia económica; directamente relacionadas a la calidad y periodicidad de la información disponible y la imposibilidad de observar directamente los efectos de las innovaciones tecnológicas que pudiera sufrir algún operador de servicios ferroviarios.The research applies the traditional economic efficiency models to a particular case study in Bolivia. The research develops around the results of the following economic efficiency models: Data Envelop Analysis (DEA), Corrected Ordinary Least Squares (COLS), Stochastic Frontier Analysis (SFA). Therefore, the results for the Railway’s System in Bolivia shows that the DEA and COLS models are more suitable for the type of data used which is based on costs functions –i.e. maintenance costs- that are rigid to stochastic perturbations. Finally, among the research findings, there are constraints to the experimental use of these models due to data quality and periodicity, also the models do not allow to arise results from current technological innovations within the Railway’s System in Bolivia

Shocks, changes in outreach and lending technologies in microfinance: The Bolivian experience

The Bolivian evidence shows that microfinance lending technologies are well designed to cope with different kinds of risk. The innovations provided in this financial sector show more strengths than weaknesses to overcome information asymmetries. Furthermore, group and individual loans are providing good mechanisms to cope with idiosyncratic and systemic shocks. Certainly, different microfinance technologies developed in Bolivia have shown good performance in terms of outreach and sustainability.La experiencia de las microfinanzas en Bolivia muestra que las tecnologías de crédito tienen un buen diseño para enfrentar diferentes tipos de riesgo. Las innovaciones realizadas en este sector financiero muestran más fortalezas que debilidades para superar los problemas de información asimétrica. De esta manera, tanto los créditos grupales como individuales proveen de buenos mecanismos para enfrentar los riesgos idiosincrásicos y sistémicos. Las tecnologías microfinancieras desarrolladas en Bolivia han demostrado un buen desempeño en términos de outreach y sostenibilidad

Diagnóstico psicopatológico y "analitica existencial": una mirada crítica a la clinica psiquiátrica desde la propuesta de L. Bisnwanger

A partir del siglo XVIII la psiquiatría focaliza su interés por constituirse como discurso científico, como discurso de la verdad acerca de la locura. Hacia 1845, en Alemania, Wilhelm Griesinger, sostiene que las enfermedades mentales son enfermedades del cerebro y propulsa un programa de investigación sobre patología cerebral que busca localizar las regiones asociadas con esta clase de trastornos. "Para Griesinger resultaba de crucial importancia que el estudio de la enfermedad mental no se aislara de la medicina general sino que se mantuviera como una parte integral de ella" (Porter, 2003).Theodor Meynert, propone algo después una clasificación de la enfermedad mental basada en criterios histopatológícos y Carl Wemike, a partir de sus descubrimientos de la localización cerebral de las regiones responsables de la afasia, reauima un intento por relacionar los síntomas psiquiátricos con anormalidades en el funcionamiento cerebral. Esta psiquiatría temprana puso el acento en el cerebro, sus afecciones y funciones básicas, recurriendo en toda instancia a explicaciones nervo-fisiológícas y biológicas y a taxonomías basadas en la etiología, la semíología y la prognosis de la enfermedad . Conviven en todo este período dos discursos, uno anátomo-patológico y otro nosográfico que buscaba caracterizar los síntomas psiquiátricos ordenándolos a partir del estudio de las funciones psicológicas básicas y sus anormalidades; desde ambas perspectivas se crearon lenguajes clasificatorios que intentaban describir a la locura como un conjunto de enfermedades que presentaba, cada una, una sintomatología y una evolución, aspectos diagnósticos, etiológicos y de prognosis (Foucault, 2003)

Pathogenic fungus in feral populations of the invasive North American bullfrog in Argentina

Nearly a third (32.4%) of the world?s amphibian species are either threatened with extinction or already extinct (1). The chytrid fungus Batrachochytrium dendrobatidis (Bd) (Chytridiomycetes: Ryzophydiales) (2) has been recognized as responsible for mass mortalities or population extinctions of numerous anuran species in different continents (e.g., 3,4,5 and citations therein). There is evidence that legal and illegal trade in amphibians as pets, food and for bio-control is one of the reasons for the spread of Bd (6,7,8,9).The North American bullfrog, Lithobates catesbeianus (Shaw, 1802) (Anura: Ranidae), has been introduced accidentally or intentionally for aquaculture into numerous countries (10). L. catesbeianus is a highly invasive species that disperses rapidly within an ecosystem (11). The oldest report of specimens of L. catesbeianus parasitized by Bd dates from 1928, and corresponds to individuals from the State of California, USA (12). Bullfrogs can be asymptomatically infected with Bd (13), and infected specimens can readily spread the disease into new geographic regions (14).Initial unsuccessful attempts to introduce bullfrogs into Argentina for farming date from 1935. A subsequent successful introduction occurred during the 1980s (10,15). Escaped individuals became established and the species spread rapidly (16). Nevertheless assessments of the presence of Bd in feral bullfrogs from Argentina are lacking (17,18).Fil: Ghirardi, Romina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Lopez, Javier Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Sanabria, Eduardo Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Juan. Facultad de Filosofía, Humanidades y Artes. Instituto de Ciencias Básicas; ArgentinaFil: Quiroga, Lorena Beatriz. Universidad Nacional de San Juan. Facultad de Filosofía, Humanidades y Artes. Instituto de Ciencias Básicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Levy, Michael G.. University of North Carolina; Estados Unido

A Tale of Two Animats: What does it take to have goals?

What does it take for a system, biological or not, to have goals? Here, this question is approached in the context of in silico artificial evolution. By examining the informational and causal properties of artificial organisms ('animats') controlled by small, adaptive neural networks (Markov Brains), this essay discusses necessary requirements for intrinsic information, autonomy, and meaning. The focus lies on comparing two types of Markov Brains that evolved in the same simple environment: one with purely feedforward connections between its elements, the other with an integrated set of elements that causally constrain each other. While both types of brains 'process' information about their environment and are equally fit, only the integrated one forms a causally autonomous entity above a background of external influences. This suggests that to assess whether goals are meaningful for a system itself, it is important to understand what the system is, rather than what it does.Comment: This article is a contribution to the FQXi 2016-2017 essay contest "Wandering Towards a Goal

Synthesis, reactivity studies, and cytotoxicity of two trans-Iodidoplatinum(II) complexes. Does photoactivation work?

trans-Platinum complexes have been the landmark in unconventional drugs prompting the development of innovative structures that might exhibit chemical and biological profiles different to cisplatin. Iodido complexes signaled a new turning point in the platinum drug design field when their cytotoxicity was reevaluated and reported. In this new study, we have synthesized and evaluated diodidoplatinum complexes trans-[PtI2(amine)(pyridine)] bearing aliphatic amines (isopropylamine and methylamine) and pyridines in trans configuration. X-ray diffraction data support the structural characterization. Their cytotoxicity has been evaluated in tumor cell lines such as SAOS-2, A375, T-47D, and HCT116. Moreover, we report their solution behavior and reactivity with biological models. Ultraviolet-a (UVA) irradiation induces an increase in their reactivity towards model nucleobase 5′-GMP in early stages, and promotes the release of the pyridine ligand (spectator ligand) at longer reaction times. Density Functional calculations have been performed and the results are compared with our previous studies with other iodido derivatives.MINECO CTQ-2015-68779

Experimental Evidence of Non-Linear Dissipation Using Acoustic Micro-Lapses

Non-linear material behaviour is observed experimentally in a laboratory using a new method called Acoustic Micro-Lapses (AML). In this approach, the shooting of two waves is synchronised in a way that the second wave (TW) is to sense the fluctuations in material stiffness induced by the first (PW). The tests include four samples; twenty trials are performed for each sample by increasing time-delays between the waves. The recorded waves are decoupled and compared to determine spectral differences by computing a quantity proportional to the energy difference as function of the increasing time delay (). For a tight sandstone and aluminium samples, the random behaviour of implies that TW finds the same equilibrium conditions as PW. The Lucite and the Berea sandstone depict distinct maxima, implying that TW sensed the transitory perturbations induced by PW. Therefore, it is inferred that PW and TW must propagate with different phase speeds. To assess the previous results, quasi-static modelling is performed using two time delayed step functions. The corresponding creep compliance shows a strong discontinuity when the second step is applied, implying the existence of two unrelaxed moduli. This supports the lab data in that the two waves must have different dispersion relations such that they propagate with different speeds