Long-Term Load Forecasting Considering Volatility Using Multiplicative Error Model

Long-term load forecasting plays a vital role for utilities and planners in terms of grid development and expansion planning. An overestimate of long-term electricity load will result in substantial wasted investment in the construction of excess power facilities, while an underestimate of future load will result in insufficient generation and unmet demand. This paper presents first-of-its-kind approach to use multiplicative error model (MEM) in forecasting load for long-term horizon. MEM originates from the structure of autoregressive conditional heteroscedasticity (ARCH) model where conditional variance is dynamically parameterized and it multiplicatively interacts with an innovation term of time-series. Historical load data, accessed from a U.S. regional transmission operator, and recession data for years 1993-2016 is used in this study. The superiority of considering volatility is proven by out-of-sample forecast results as well as directional accuracy during the great economic recession of 2008. To incorporate future volatility, backtesting of MEM model is performed. Two performance indicators used to assess the proposed model are mean absolute percentage error (for both in-sample model fit and out-of-sample forecasts) and directional accuracy.Comment: 19 pages, 11 figures, 3 table

Una comunidad altamente diversa de moluscos asociados a praderas de Zostera marina del mar de Alborán: preferencias de micro-hábitat, grupos tróficos y distribución biogeográfica

The fauna of molluscs associated with deep subtidal Zostera marina beds (12-16 m) in southern Spain (Alboran Sea) has been characterised in terms of micro-habitat preference, feeding guilds and biogeographical affinity. The species list (162 taxa) is based on sampling completed before the strong eelgrass decline experienced in 2005-2006, using different methods (small Agassiz trawl covering 222 m2 and quadrates covering 0.06 m2) and different temporal scales (months, day/night). Dominant epifaunal species are Jujubinus striatus, Rissoa spp. and Smaragdia viridis in the leaf stratum and Nassarius pygmaeus, Bittium reticulatum and Calliostoma planatum on the sediment. Nevertheless, the infauna dominated the epifauna in terms of number of individuals, including mainly bivalves (Tellina distorta, T. fabula, Dosinia lupinus). The epifauna of both the sediment and leaf strata included high numbers of species, probably due to the soft transition between vegetated and unvegetated areas. The dominant feeding guilds were deposit feeders, filter feeders and peryphiton grazers, but ectoparasites (eulimids), seagrass grazers (Smaragdia viridis) and an egg feeder (Mitrella minor) also occurred, unlike in other eelgrass beds of Europe. The molluscan fauna of these Z. marina beds is essentially derived from the local fauna, which includes many widely distributed species along European coasts, with a low representation of strictly Mediterranean or strictly Atlantic species. This fauna is richer than that found in other eelgrass beds of Europe, and deserves important attention for conservation.La fauna de moluscos asociada a praderas infralitorales profundas de Zostera marina (12-16 m) del sur de España (mar de Alborán) ha sido caracterizada en relación a su micro-hábitat preferente, grupo trófico y distribución biogeográfica. El listado faunístico (162 especies) se obtuvo antes de la fuerte regresión sufrida entre los años 2005 y 2006, usando diferentes métodos (pequeño patín de Agassiz que muestreaba 222 m2 y cuadrantes que muestreaban 0.06 m2) y escalas temporales (meses, día/noche). Las especies dominantes asociadas al estrato foliar son Jujubinus striatus, Rissoa spp. y Smaragdia viridis y al sedimento son Nassarius pygmaeus, Calliostoma planatum y Bittium reticulatum, entre otras. No obstante, la endofauna domina a la epifauna, incluyendo principalmente bivalvos como Tellina distorta, T. fabula y Dosinia lupinus. La epifauna asociada al sedimento y al estrato foliar tiene una gran riqueza de especies, probablemente debido a la suave transición entre zonas cubiertas y no cubiertas. Los grupos tróficos dominantes fueron los depositívoros, filtradores o ramoneadores, pero ectoparásitos (eulímidos) y consumidores de fanerógamas marinas (Smaragdia viridis) o de puestas (Mitrella minor) también estuvieron presentes al contrario que en otras praderas de Z. marina de Europa. La fauna de moluscos asociados a Z. marina proviene del gran grupo de especies presentes en la zona, e incluye fundamentalmente especies de amplia distribución a lo largo de las costas europeas, con una baja representación de especies estrictamente Mediterráneas o Atlánticas. Esta fauna es más rica que la encontrada en otras praderas de Z. marina de Europa, lo cual reclama medidas eficientes para una mejor conservación medioambiental de este tipo de hábitat

A comprehensive characterisation of the fibre composition and properties of a limb (Flexor digitorum superficialis, membri thoraci) and a trunk (Psoas major) muscle in cattle

<p>Abstract</p> <p>Background</p> <p>The fibre type attributes and the relationships among their properties play an important role in the differences in muscle capabilities and features. Comprehensive characterisation of the skeletal muscles should study the degree of association between them and their involvement in muscle functionality. The purposes of the present study were to characterise the fibre type composition of a trunk (<it>Psoas major</it>, PM) and a limb (<it>Flexor digitorum, membri thoraci</it>, FD) muscle in the bovine species and to study the degree of coordination among contractile, metabolic and histological properties of fibre types. Immunohistochemical, histochemical and histological techniques were used.</p> <p>Results</p> <p>The fibre type composition was delineated immunohistochemically in calf muscle samples, identifying three pure (I, IIA, and IIX) and two hybrid type fibres (I+IIA, and IIAX). Most of the fibres in FD were types I and IIA, while pure IIX were absent. All fibre types were found in PM, the IIX type being the most frequent. Compared to other species, small populations of hybrid fibres were detected. The five fibre types, previously identified, were ascribed to three different acid and alkaline mATPase activity patterns. Type I fibres had the highest oxidative capacity and the lowest glycolytic capacity. The reverse was true for the IIX fibres, whereas the type IIA fibres showed intermediate properties. Regarding the histological properties, type I fibres tended to be more capillarised than the II types. Correlations among contractile, metabolic and histological features on individual fibres were significantly different from zero (r values varied between -0.31 and 0.78). Hybrid fibre values were positioned between their corresponding pure types, and their positions were different regarding their metabolic and contractile properties.</p> <p>Conclusion</p> <p>Coordination among the contractile, metabolic and histological properties of fibres has been observed. However, the magnitude of the correlation among them is always below 0.8, suggesting that the properties of muscles are not fully explained by the fibre composition. These results support the concept that, to some extent, muscle plasticity can be explained by the fibre type composition, and by the properties derived from their metabolic and histological profiles.</p

Disentangling the influence of fishing, demography and environment on population dynamics of Iberian Peninsula waters fish stocks

Overexploitation and climate change are increasingly causing unanticipated changes in marine ecosystems such as higher variability in fish recruitment or shifts in species dominance and distribution that alter the productivity of fish stocks. This study analyses how external and internal drivers influence population dynamics of hake (Merluccius merluccius), white anglerfish (Lophius piscatorius), four-spot megrim (Lepidorhombus boscii), and horse mackerel (Trachurus trachurus) of Iberian Peninsula waters of the Northeast Atlantic across different spatiotemporal scales. Available spawning stock biomass and recruitment have been used as biological data, whereas fishing mortality, demographic data as well as climatic and oceanographic data have been used as drivers. The obtained results indicate that population dynamics of these species are mainly driven by oceanographic variability at regional scale along with fishing pressure and demographic factors, while the impact of large-scale climate indices was minimal. The identified variables represent relevant oceanographic regional processes candidate to be potentially integrated into the stock assessment models and management procedures of these important fishery resource

Diagnosing rotator cuff tears (clinical tests and imaging). Current concepts review

Hay dificultad en lograr un adecuado diagnóstico clínico en la patología subacromial y del manguito de los rotadores, y es importante reconocer estas razones: el patrón de dolor en el hombro no es específico de ninguna enfermedad; los problemas del manguito de los rotadores presentan diferentes formas de presentación y de patología, y rara vez se encuentran de forma aislada; las pruebas clínicas descritas inicialmente para una patología específica del hombro son positivas para determinar una gran variedad de trastornos, sin lograr diferenciarlos, y algunas alteraciones anatómicas no son sintomáticas y no necesitan ningún tratamiento. La realización e interpretación de una adecuada exploración física más la utilización de las ayudas imagenológicas pertinentes permitirán la orientación adecuada en la patología del manguito de los rotadores para decidir la mejor opción médico-quirúrgica para nuestros pacientes. Nivel de evidencia clínica: Nivel IV.It is difficult to achieve an appropriate clinical diagnosis in subacromial pathology that involve the rotator cuff. It is important to recognize the following reasons: the pattern of shoulder pain is not specific to any disease; rotator cuff problems have different presentations and pathologies, rarely found isolated;the initially described clinicaltests for a specific shoulderpathology are a positive way to determine a variety of disorders, without differentiating them, and some anatomical alterations may not be symptomatic and need no treatment. The performance and interpretation of an adequate physical examination plus the use of relevant imaging aids will allow to properly approach and assess the rotator cuff pathology in order to decide the best medical-surgical option for any patient. Evidence level: IV

The Blackspot seabream Spanish target fishery of the Strait of Gibraltar: updating the available information

This paper includes the available information of the Blackspot seabream (Pagellus bogaraveo) Spanish target fishery in the Strait of Gibraltar updating the documents presented in previous years with the information from 2019. So, data about landings, fishing effort, CPUEs and landings length frequencies are presented to its discussion within the 2020 WGDEEP

Realistic Exact Solution for the Exterior Field of a Rotating Neutron Star

A new six-parametric, axisymmetric and asymptotically flat exact solution of Einstein-Maxwell field equations having reflection symmetry is presented. It has arbitrary physical parameters of mass, angular momentum, mass--quadrupole moment, current octupole moment, electric charge and magnetic dipole, so it can represent the exterior field of a rotating, deformed, magnetized and charged object; some properties of the closed-form analytic solution such as its multipolar structure, electromagnetic fields and singularities are also presented. In the vacuum case, this analytic solution is matched to some numerical interior solutions representing neutron stars, calculated by Berti & Stergioulas (Mon. Not. Roy. Astron. Soc. 350, 1416 (2004)), imposing that the multipole moments be the same. As an independent test of accuracy of the solution to describe exterior fields of neutron stars, we present an extensive comparison of the radii of innermost stable circular orbits (ISCOs) obtained from Berti & Stergioulas numerical solutions, Kerr solution (Phys. Rev. Lett. 11, 237 (1963)), Hartle & Thorne solution (Ap. J. 153, 807, (1968)), an analytic series expansion derived by Shibata & Sasaki (Phys. Rev. D. 58 104011 (1998)) and, our exact solution. We found that radii of ISCOs from our solution fits better than others with realistic numerical interior solutions.Comment: 13 pages, 13 figures, LaTeX documen

Application of Project-Based Learning in the development of a Bachelor’s Thesis in the Bachelor’s Degree in Civil Engineering

El Aprendizaje Basado en Proyectos (ABP) es un enfoque educativo que consigue motivar al alumnado a través de su implicación activa en el desarrollo de un trabajo que tiene un alto componente práctico. En consecuencia, se genera un aprendizaje profundo de los temas tratados. Con la finalidad de alcanzar estas metas, se aplicó el ABP al Trabajo Final de Grado (TFG) de cuatro alumnos del Grado en Ingeniería Civil de la Universitat Politècnica de València. El trabajo realizado consistió en el diseño, construcción, ensayo y análisis de un modelo reducido de una estructura de hormigón armado. La metodología empleada consistió en la definición de las actividades prácticas y teóricas necesarias para desarrollar el proyecto sobre el elemento estructural y el establecimiento de un sistema de seguimiento por parte del tutor. Los resultados obtenidos demuestran el buen funcionamiento de la innovación, que consiguió motivar a los alumnos, potenciar su aprendizaje y facilitar el alcance de las competencias establecidas en el TFG y otras propias de la titulación, así como despertar el interés de los alumnos por el cálculo de estructuras de hormigón.Project-Based Learning (PBL) is an educational approach that motivates students through their active involvement in the development of a highly practical assignment. As a result, a deep learning process is generated. In order to achieve these goals, PBL was applied to the Bachelor’s Thesis (BT) of four students of the Degree in Civil Engineering of the Universitat Politècnica de València. The work consisted of the design, construction, testing and analysis of a scaled-down model of a reinforced concrete structure. The methodology used consisted of defining the practical and theoretical activities necessary to develop the project on the structural element and the establishment of a monitoring system by the tutor. The results obtained demonstrate the good performance of the innovation, which motivated the students, enhanced their learning and facilitated the achievement of the competences established in the BT and others specific to the degree, as well as awakened the students' interest in the calculation of concrete structures

The Blackspot seabream Spanish target fishery of the Strait of Gibraltar: updating the available information

This paper includes the available information of the Blackspot seabream (Pagellus bogaraveo) Spanish “voracera” target fishery of the Strait of Gibraltar. The documents presented in previous years were updated with the 2020 information: data about landings, fishing effort, CPUEs and landings length frequencies are presented to its discussion within the 2021 WGDEEP

Controls of Multimodal Wave Conditions in a Complex Coastal Setting

Coastal hazards emerge from the combined effect of wave conditions and sea level anomalies associated with storms or low-frequency atmosphere-ocean oscillations. Rigorous characterization of wave climate is limited by the availability of spectral wave observations, the computational cost of dynamical simulations, and the ability to link wave-generating atmospheric patterns with coastal conditions. We present a hybrid statistical-dynamical approach to simulating nearshore wave climate in complex coastal settings, demonstrated in the Southern California Bight, where waves arriving from distant, disparate locations are refracted over complex bathymetry and shadowed by offshore islands. Contributions of wave families and large-scale atmospheric drivers to nearshore wave energy flux are analyzed. Results highlight the variability of influences controlling wave conditions along neighboring coastlines. The universal method demonstrated here can be applied to complex coastal settings worldwide, facilitating analysis of the effects of climate change on nearshore wave climate.This work was funded by the U.S. Geological Survey (USGS) Coastal and Marine Geology Program. The authors thank Jorge Perez, IH Cantabria, for providing the GOW wave hindcast and for assistance with wave spectra, and Sean Vitousek, University of Chicago, for a helpful review. This material is based upon work supported by the U.S. Geological Survey under grant/cooperative agreement GI5AC00426. A. R., J. A. A. A., and F. J. M. acknowledge the support of the Spanish “Ministerio de Economía y Competitividad” under grant BIA2014-59643-R. J. A. A. A. was funded by the Spanish “Ministerio de Educación, Cultura y Deporte” FPU (Formación del Profesorado Universitario) studentship BOE-A-2013-12235. Reanalyses of ocean data are available for research purposes through IH Cantabria (contact [email protected]). Southern California Bight look-up table data are available at https://doi.org/10.1594/PANGAEA.880314. Related Southern California nearshore wave data can be found at http://dx.doi.org/10.5066/F7N29V2V