New Constraints on the Timing and Pattern of Deglaciation in the Húnaflói Bay Region of Northwest Iceland Using Cosmogenic 36CA Dating and Geomorphic Mapping

Understanding the evolution and timing of changes in ice sheet geometry and extent in Iceland during the Last Glacial Maximum (LGM) and subsequent deglaciation continues to stimulate much active research. Though many previous studies have advanced our knowledge of Icelandic ice sheet history preserved in marine and terrestrial settings (e.g., Andrews et al., 2000; Norðdahl et al., 2008), the timing of ice margin retreat remains largely unknown in several key regions. Recently published 36Cl surface exposure ages of bedrock surfaces and moraines in the West Fjords (Brynjólfsson et al., 2015) contribute important progress in establishing more precise age control of ice recession in northwest Iceland. In another recent study, the spatial pattern and style of deglaciation in northern Iceland have been revealed through geomorphic mapping and GIS analyses of glacial landforms (Principato et al., 2016). Additional insight comes from updated numerical modeling reconstructions, which now provide a series of glaciologically plausible Icelandic ice sheet configurations from the LGM through the last deglaciation (Patton et al., 2017). However, the optimization of ice sheet model simulations relies on critical comparisons with the available empirical record of glacial-geologic evidence and chronological control, which remains relatively limited and sparsely distributed throughout Iceland. Our investigation is motivated by the need for more accurate constraints on the deglacial history in northern Iceland, where dated terrestrial records of ice margin retreat are particularly scarce. (excerpt

Theory of generalized trigonometric functions: From Laguerre to Airy forms

We develop a new point of view to introduce families of functions, which can be identified as generalization of the ordinary trigonometric or hyperbolic functions. They are defined using a procedure based on umbral methods, inspired by the Bessel Calculus of Bochner, Cholewinsky and Haimo. We propose further extensions of the method and of the relevant concepts as well and obtain new families of integral transforms allowing the framing of the previous concepts within the context of generalized Borel transform

Inverse derivative operator and umbral methods for the harmonic numbers and telescopic series study

The formalism of differ-integral calculus, initially developed to treat differential operators of fractional order, realizes a complete symmetry between differential and integral operators. This possibility has opened new and interesting scenarios, once extended to positive and negative order derivatives. The associated rules offer an elegant, yet powerful, tool to deal with integral operators, viewed as derivatives of order-1. Although it is well known that the integration is the inverse of the derivative operation, the aforementioned rules offer a new mean to obtain either an explicit iteration of the integration by parts or a general formula to obtain the primitive of any infinitely differentiable function. We show that the method provides an unexpected link with generalized telescoping series, yields new useful tools for the relevant treatment, and allows a practically unexhausted tool to derive identities involving harmonic numbers and the associated generalized forms. It is eventually shown that embedding the differ-integral point of view with techniques of umbral algebraic nature offers a new insight into, and the possibility of, establishing a new and more powerful formalism

Las representaciones pictóricas como recursos semióticos. Caso equilibrio químico

De acuerdo con Orlandi (1996) tres variables intervienen en el proceso de producción de sentidos: la intencionalidad del autor, la materialidad del texto y las posibilidades de resignificación del lector. Las dos primeras no pueden ser modificadas por el lector. Las posibilidades del lector para atribuir significados pueden ser modificadas conociendo los diferentes tipos de Representaciones Externas Pictóricas (REP) y los recursos semióticos que se utilizan en su construcción. Se diseña una intervención dirigida a dar a conocer este contenido para dos tipos REP y así facilitar operar con éstas. Los resultados indican que las REP ejercen una doble influencia: a) cuando la tarea se realiza a partir de una REP o b) cuando la tarea es construir la REP. En ambos casos se encuentra que cada tipo de representación permite la recuperación de una información específica y diferente

Fractional derivatives, memory kernels and solution of a free electron laser volterra type equation

The high gain free electron laser (FEL) equation is a Volterra type integro-differential equation amenable for analytical solutions in a limited number of cases. In this note, a novel technique, based on an expansion employing a family of two variable Hermite polynomials, is shown to provide straightforward analytical solutions for cases hardly solvable with conventional means. The possibility of extending the method by the use of expansion using different polynomials (two variable Legendre like) expansion is also discussed

Some properties and generating functions of generalized harmonic numbers

In this paper, we introduce higher-order harmonic numbers and derive their relevant properties and generating functions by using an umbral-type method. We discuss the link with recent works on the subject, and show that the combinations of umbral and other techniques (such as the Laplace and other types of integral transforms) yield a very efficient tool to explore the properties of these numbers

Integrals of Special Functions and Umbral Methods

AbstractWe derive integrals of combination of Gauss and Bessel functions, by the use of umbral techniques. We show that the method allows the possibility of pursuing new and apparently fruitful avenues in the theory of special functions, displaying interesting links with the theory and the formalism of integral transforms

Repeated derivatives of hyperbolic trigonometric functions and associated polynomials

Elementary problems as the evaluation of repeated derivatives of ordinary transcendent functionscan usefully be treated with the use of special polynomials and of a formalism borrowed from combinatorial analysis. Motivated by previous researches in this field, we review the results obtained by other authors and develop a complementary point of view for the repeated derivatives of sec(.), tan(.) and for their hyperbolic counterparts