The Health State of the Cryosphere

The term cryosphere is used to refer to all portions of the Earth surface where water appears in solid form. This includes the snow cover; sea, lake and river ice; glaciers, ice caps and ice sheets; and permafrost. The aim of this contribution is to present the current state of the cryosphere. Emphasis will be given to sea ice and continental ice masses (glaciers, ice caps and ice sheets), and the contribution of the losses from the latter to sea level rise (SLR)

Internal Structure of Ariebreen, Spitsbergen, from radio-echo sounding data

Ariebreen (77º 01' N, 15º 29' E) is a small valley glacier (ca. 0.36 km2 in August 2007) located at Hornsund, Spitsbergen, Svalbard, ca. 2.5 km to the west of Hornsund Polish Polar Station. Ariebreen, like many other Svalbard glaciers, has experienced a significant recession at least since the 1930s, and most likely since the end of Little Ice Age (LIA) in the early part of the 20th century. Moreover, the thinning rate of western Svalbard glaciers has shown an acceleration during the most recent decades. Ariebreen follows this general retreat pattern, as is shown in another contribution to this workshop (Petlicki et al., 2008). Most investigated glaciers in Hornsund area, in the neighbourhood of Ariebreen, are known to be polythermal (e.g. Hansbreen and Werenskioldbreen, Pälli et al., 2003). It has been suggested (Macheret et al., 1992) that the thinning of polythermal glaciers may result in a switch to cold thermal structure under appropriate conditions. The strong thinning experienced by Ariebreen during the recent decades makes it an ideal candidate to undergo such change. The main aims of this contribution are to understand the internal structure of Ariebreen, in particular, its hydrothermal regime, and to determine whether the glacier is undergoing or has already experienced a transition from polythermal to cold structure. The main tool to accomplish this will be the analysis of radio-echo sounding data

A compact lightweight multipurpose ground-penetrating radar for glaciological applications

We describe a compact lightweight impulse radar for radio-echo sounding of subsurface structures designed specifically for glaciological applications. The radar operates at frequencies between 10 and 75 MHz. Its main advantages are that it has a high signal-to-noise ratio and a corresponding wide dynamic range of 132 dB due mainly to its ability to perform real-time stacking (up to 4096 traces) as well as to the high transmitted power (peak voltage 2800 V). The maximum recording time window, 40 ?s at 100 MHz sampling frequency, results in possible radar returns from as deep as 3300 m. It is a versatile radar, suitable for different geophysical measurements (common-offset profiling, common midpoint, transillumination, etc.) and for different profiling set-ups, such as a snowmobile and sledge convoy or carried in a backpack and operated by a single person. Its low power consumption (6.6 W for the transmitter and 7.5 W for the receiver) allows the system to operate under battery power for mayor que7 hours with a total weight of menor que9 kg for all equipment, antennas and batteries

Ice volume changes of Ariebreen, Spitsbergen, during 1936-1990-2007

Ariebreen (77º 01' N, 15º 29' E) is a small valley glacier (ca. 0.36 km2 in August 2007) located at Hornsund, Spitsbergen, Svalbard, ca. 2.5 km to the west of Hornsund Polish Polar Station. Many Svalbard glaciers have experienced a significant recession at least since the 1930s, and most likely since the end of Little Ice Age in the early 20th century (Werner, 1993). It has manifested as thinning and retreating of ice fronts, though a simultaneous thickening at the uppermost elevations in many locations has been reported (Bamber et al., 2004; Nuth et al., 2007). Moreover, the thinning rate of western Svalbard glaciers has shown an acceleration during the most recent decades (Kohler et al., 2007). The main aims of this contribution are to determine whether Ariebreen follows such retreat pattern and to quantify the retreat it has experienced, in terms of area, thickness and volume changes, to estimate the average mass balance equivalent to the ice volume change during the period under investigation, and to estimate the volume of ice presently stored in Ariebreen. The main tools to accomplish this will be the analysis of digital terrain models (DTM) of the glacier surface corresponding to different dates, and the radio-echo sounding of the ice body to determine the present ice volume. The latter is described in a separate contribution to this workshop (Navarro et al., 2008)

Creeping and structural effects in Faradaic artificial muscles

Reliable polymeric motors are required for the construction of rising accurate robots for surgeon assistance. Artificial muscles based on the electrochemistry of conducting polymers fulfil most of the required characteristics, except the presence of creeping effects during actuation. To avoid it, or to control it, a deeper knowledge of its physicochemical origin is required. With this aim here bending bilayer tape/PPy-DBSH (Polypyrrole-dodecylbenzylsulphonic acid) full polymeric artificial muscles were cycled between −2.5 and 1 V in aqueous solutions with parallel video recording of the described angular movement. Coulo-voltammetric (charge-potential, QE), dynamo-voltammetric (angle-potential, αE), and coulo-dynamic (charge-angle, Qα) muscular responses corroborate that 10 % of the charge is consumed by irreversible reactions overlapping the polymer reduction at the most cathodic potentials. In parallel, the range of the bending angular movement (145°) shifts by 15° per cycle (creeping effect) pointing to the irreversible charge as possible origin of the irreversible swelling of the PPy-DBS film. Different slopes in the closed loop part of the QE identify the different reaction driven structural processes in the film: oxidation-shrinking, oxidation compaction, reduction-relaxation, reduction-swelling, and reduction-vesicle’s formation. Despite the irreversible charge fraction, the muscle motor keeps a Faradaic behaviour: described angles are linear functions of the consumed charge in the full potential range

La construcción de subjetividades en el sistema sanitario público de Andalucía (España)

En este artículo presentamos los resultados de una investigación más amplia donde, apoyándonos en el concepto de repertorio interpretativo propuesto por Jonathan Potter y Margaret Wetherell, analizamos el entramado discursivo emergente del Sistema Sanitario Público Andaluz en cuanto a los argumentos-ideas que sostiene. En un artículo previo, identificamos tres grandes grupos discursivos que denominamos como críticos, ontológicos y legitimadores. En esta segunda fase, abordamos las subjetividades construidas desde los anteriores repertorios destacando la presencia de tres categorías de sujetos: los asistenciales, los no asistenciales y los ciudadanos. Señalamos la naturaleza multi-discursiva de la organización y, por tanto, la multi-referencialidad inherente a los procesos de construcción de subjetividades, así como las -posibles- consecuencias organizativas de asumir un tipo u otro de subjetividad. Concluimos planteando la necesidad de adoptar un modelo dialógico de gestión que incluya dicha variedad multi-discursiva del sistema hacia una misma dirección.In this paper, we present the results of a larger investigation in which, relying on the concept of interpretative repertoire put forward by Potter and Wetherell, we analyze the emerging discursive framework of the Andalusian Public Health System in terms of the arguments-ideas behind such framework. In a previous paper, we identified three major discursive groups that we labelled as critical, ontological, and legitimating. At this second stage, we address the subjectivities constructed on the basis of these repertoires and we emphasize three categories of subjects: healthcare, non-healthcare, and citizens. We draw attention to the multi-discursive nature of the organization and, therefore, the multi-referentiality inherent in the processes of subjectivity construction as well as the -potential- organisational consequences of assuming one or another type of subjectivity. We conclude by proposing the need for a dialogic model of management that includes the system's multi-discursive variety toward a same direction

Sensitivity of a distributed temperature-radiation index melt model based on AWS observations and surface energy balance fluxes, Hurd Peninsula glaciers, Livingston Island, Antarctica

We use an automatic weather station and surface mass balance dataset spanning four melt seasons collected on Hurd Peninsula Glaciers, South Shetland Islands, to investigate the point surface energy balance, to determine the absolute and relative contribution of the various energy fluxes acting on the glacier surface and to estimate the sensitivity of melt to ambient temperature changes. Long-wave incoming radiation is the main energy source for melt, while short-wave radiation is the most important flux controlling the variation of both seasonal and daily mean surface energy balance. Short-wave and long-wave radiation fluxes do, in general, balance each other, resulting in a high correspondence between daily mean net radiation flux and available melt energy flux. We calibrate a distributed melt model driven by air temperature and an expression for the incoming short-wave radiation. The model is calibrated with the data from one of the melt seasons and validated with the data of the three remaining seasons. The model results deviate at most 140 mm w.e. from the corresponding observations using the glaciological method. The model is very sensitive to changes in ambient temperature: a 0.5 ◦ C increase results in 56 % higher melt rates

Data Reduction in the String Space for Efficient kNN Classification through Space Partitioning

Within the Pattern Recognition field, two representations are generally considered for encoding the data: statistical codifications, which describe elements as feature vectors, and structural representations, which encode elements as high-level symbolic data structures such as strings, trees or graphs. While the vast majority of classifiers are capable of addressing statistical spaces, only some particular methods are suitable for structural representations. The kNN classifier constitutes one of the scarce examples of algorithms capable of tackling both statistical and structural spaces. This method is based on the computation of the dissimilarity between all the samples of the set, which is the main reason for its high versatility, but in turn, for its low efficiency as well. Prototype Generation is one of the possibilities for palliating this issue. These mechanisms generate a reduced version of the initial dataset by performing data transformation and aggregation processes on the initial collection. Nevertheless, these generation processes are quite dependent on the data representation considered, being not generally well defined for structural data. In this work we present the adaptation of the generation-based reduction algorithm Reduction through Homogeneous Clusters to the case of string data. This algorithm performs the reduction by partitioning the space into class-homogeneous clusters for then generating a representative prototype as the median value of each group. Thus, the main issue to tackle is the retrieval of the median element of a set of strings. Our comprehensive experimentation comparatively assesses the performance of this algorithm in both the statistical and the string-based spaces. Results prove the relevance of our approach by showing a competitive compromise between classification rate and data reduction.This research work was partially funded by “Programa I+D+i de la Generalitat Valenciana” through grant ACIF/2019/ 042 and the Spanish Ministry through HISPAMUS project TIN2017-86576-R, partially funded by the EU

Exploiting the Two-Dimensional Nature of Agnostic Music Notation for Neural Optical Music Recognition

State-of-the-art Optical Music Recognition (OMR) techniques follow an end-to-end or holistic approach, i.e., a sole stage for completely processing a single-staff section image and for retrieving the symbols that appear therein. Such recognition systems are characterized by not requiring an exact alignment between each staff and their corresponding labels, hence facilitating the creation and retrieval of labeled corpora. Most commonly, these approaches consider an agnostic music representation, which characterizes music symbols by their shape and height (vertical position in the staff). However, this double nature is ignored since, in the learning process, these two features are treated as a single symbol. This work aims to exploit this trademark that differentiates music notation from other similar domains, such as text, by introducing a novel end-to-end approach to solve the OMR task at a staff-line level. We consider two Convolutional Recurrent Neural Network (CRNN) schemes trained to simultaneously extract the shape and height information and to propose different policies for eventually merging them at the actual neural level. The results obtained for two corpora of monophonic early music manuscripts prove that our proposal significantly decreases the recognition error in figures ranging between 14.4% and 25.6% in the best-case scenarios when compared to the baseline considered.This research work was partially funded by the University of Alicante through project GRE19-04, by the “Programa I+D+i de la Generalitat Valenciana” through grant APOSTD/2020/256, and by the Spanish Ministerio de Universidades through grant FPU19/04957