Validació d'un nou instrument per a la mesura d'inestabilitat de la pel.lícula llagrimal

La mesura de la pel·lícula llagrimal és fonamental en la pràctica optomètrica. Les tècniques clíniques utilitzades fins avui per mesurar la qualitat de la pel·lícula llagrimal han implicat subjectivitat i invasivitat en la determinació dels valors com el BUT. Això ha dificultat el diagnòstic d’una de les patologies oculars més comuns, el síndrome d’ull sec. Es per això que s’ha vist necessari desenvolupar tecnologies per realitzar l’avaluació de la llàgrima de manera no invasiva i objectiva. Una d’aquestes tecnologies es la que presenta MYAH, un instrument que, entre altres coses, permet fer l’avaluació completa de la llàgrima a través de proves com el NIBUT, BUT, menisc llagrimal o observació de glàndules de Meibom. L’objectiu del treball ha sigut comprovar si el MYAH és vàlid per mesurar objectivament la pel·lícula llagrimal comparant-lo amb les tècniques més utilitzades, el BUT amb biomicroscopi i el NIBUT. Els resultats amb diferents tècniques eren similars. En l’anàlisi es va observar que les diferències eren significatives i per tant no podien intercanviar-se les tècniques a l’hora de mesurar la ruptura de la pel·lícula llagrimal. Els motius d’aquestes diferències podien ser la instil·lació de fluoresceïna en dues tècniques o la pròpia inestabilitat de la llàgrima. Els resultats mostraren que la diferència entre dues tècniques invasives era menor que entre una tècnica invasiva com el BUT amb biomicroscopi i una no invasiva, com el NIBUT en el MYAH.La medida de la película lagrimal es fundamental en la práctica optométrica. Las técnicas clínicas utilizadas hasta hoy para medir la calidad de la película lagrimal han implicado subjetividad e invasividad en la determinación de valores como el BUT. Esto ha dificultado el diagnóstico de una de las patologías oculares más comunes, el síndrome de ojo seco. Es por eso que se ha visto necesario desarrollar tecnologías para evaluar la lágrima de manera no invasiva y objetiva. Una de estas tecnologías es la que presenta el MYAH, un instrumento que, entre otras cosas, permite hacer una evaluación completa de la película lagrimal a través de pruebas como el NIBUT, BUT, menisco lagrimal y observación de las glándulas de Meibomio. El objetivo del trabajo ha sido comprobar si el MYAH es válido para medir objetivamente la película lagrimal al compararlo con otras técnicas mas utilizadas, el BUT con biomicroscopio y NIBUT. Los resultados con diferentes técnicas eran similares. En el análisis se observó que las diferencias eran significativas y por tanto no podían intercambiarse las técnicas a la hora de medir el tiempo de ruptura lagrimal. Los motivos de estas diferencias podían deberse a la instilación de fluoresceína en dos técnicas o a la propia inestabilidad de la lágrima. Los resultados mostraron que la diferencia entre las dos técnicas invasivas era menor que entre técnica invasiva como el BUT y técnica no invasiva como el NIBUT.Tear film measurement is fundamental in optometric practice. The clinical techniques used nowadays, such as the BUT technique are still invasive and subjective when it comes to tear film measurement. Because of this, one of the most common ocular conditions, the dry eye disease, has been more difficult to diagnose. Therefore, it has become necessary to develop non-invasive and objective technologies for tear measurement. One of these technologies is MYAH, an instrument that, among other things, allows a complete evaluation of the tear film through tests such as NIBUT, BUT, tear meniscus or observation of Meibom glands. The aim of the study was to test whether MYAH is valid for objectively measuring tear film by comparing it with the most common techniques: BUT with the slit lamp and NIBUT. The results were similar comparing different techniques. The analysis showed that the differences were significant and therefore the techniques used for measuring tear break up time could not be exchanged between them. Some reasons as why these differences exist could be the instillation of fluorescein into two techniques or the instability of the tear film itself. The results showed that the differences between the two invasive techniques was less than between an invasive technique such as BUT with slit lamp and a non-invasive one, such as NIBUT in MYAH

Simulation and Optimization of photoFenton process

Este trabajo esta dedicado a la simulación de una proceso avanzado de oxidación (AOP) denominado photo-Fenton. Este proceso se basa en la descomposición de la materia orgánica usando radicales libres obtenidos con el peróxido de hidrogeno y el hierro (Fe2+). Para ello se ha buscado un modelo que describa el sistema correctamente sin que este se vuelva demasiado complejo y difícil de usar. Tambien incluye una propuesta para el ajuste de parámetros y para la optimización del proceso, mostrando que existe un gran abanico de posibilidades en cuanto a la función objetivo y los métodos usados

Improving the modeling of geomagnetically induced currents in Spain

Vulnerability assessments of the risk posed by geomagnetically induced currents (GICs) to power transmission grids benefit from accurate knowledge of the geomagnetic field variations at each node of the grid, the Earth's geoelectrical structures beneath them, and the topology and relative resistances of the grid elements in the precise instant of a storm. The results of previous analyses on the threat posed by GICs to the Spanish 400 kV grid are improved in this study by resorting to different strategies to progress in the three aspects identified above. First, although at midlatitude regions the source fields are rather uniform, we have investigated the effect of their spatial changes by interpolating the field from the records of several close observatories with different techniques. Second, we have performed a magnetotelluric (MT) sounding in the vicinity of one of the transformers where GICs are measured to determine the geoelectrical structure of the Earth, and we have identified the importance of estimating the MT impedance tensor when predicting GIC, especially where the effect of lateral heterogeneities is important. Finally, a sensitivity analysis to network changes has allowed us to assess the reliability of both the information about the network topology and resistances, and the assumptions made when all the details or the network status are not available. In our case, the most essential issue to improve the coincidence between model predictions and actual observations came from the use of realistic geoelectric information involving local MT measurements

Advanced tools for ITER Tritium Plant System Modeling & Design

Chemical plant system modeling experience based on the use of largely validated commercial modeling tools such as the Aspen HYSYS is adapted and exploited to develop numeric routines for unitary isotopic operations, including permeation, cold trapping, reversible absorption, and cryogenic distillation, for the ITER tritium plant systems. Model prediction capabilities and isotopic database inputs for first-principle models are discussed. Numeric implementation of the Aspen HYSYS routines are presentedPeer ReviewedPostprint (author's final draft

Long-term trends in functional diversity of exploited marine fish in the Azores’ archipelago: past and present

IntroductionEffective fisheries management requires monitoring and quantifying changes in exploited fish communities. Concerns about global fisheries sustainability have led to innovative approaches. Functional diversity, rooted in ecological theory, offers valuable insights into fishery activities and ecosystem processes. A trait-based approach was used to investigate the functional diversity of landed fish species in the Azores archipelago from 1980 to 2021.MethodsLandings data of exploited Actinopterygii and Elasmobranchii were provided by the Azores Fisheries Auction Services (LOTAÇOR/OKEANOS-UAc Fisheries Database). A trait matrix was built, incorporating 12 functional traits assigned to each species, capturing their importance in marine ecological processes. The Quickhull algorithm for convex hull was employed to calculate the volume occupied by the species in the four-dimensional functional space. Functional diversity (FD) was measured using three indices: functional richness (FRic), functional evenness (FEve), and functional divergence (FDiv). Trends in FD indices over the past 42 years were visualized using Generalized Additive Models (GAM) with interaction terms.Results and discussionGAM analysis revealed significant variations in the functional space and FD metrics over time. FRic exhibited peaks in the 1980s and 2010s, declining in the 1990s and from the 2010s onwards, indicating diversification in target species. The recent decrease in FRic can be attributed to the absence of catches of species with unique traits. The distribution of landings and trait combinations showed higher regularity in the functional space during the 1980s and 1990s (high FEve). Actinopterygii species targeted in the 1980s and 1990s had lower trait divergence (low FDiv) compared to those targeted from the 2000s onwards (high FDiv). Variability in FD can be linked to changes in fishing practices, species availability, market demand, environmental factors, and local regulations. This study underscores the importance of considering FD metrics alongside species richness and abundance when assessing the potential effects of fisheries on marine ecosystems and sustainable use of fishery resources

New geoelectrical characterization of a continental collision zone in the Central - Eastern Pyrenees: Constraints from 3-D joint inversion of electromagnetic data

Continent-continent collisions are responsible for the formation of large mountain ranges like the Himalayas and the Alps and play a primary role in the development of the continents. The continental collision between the Iberian and European plates during the Alpine Orogeny resulted in the formation of the Pyrenees. In this study new electromagnetic data from the Eastern Pyrenees were complemented with older data from the Central Pyrenees, constraining the physical and geological processes at the eastern end of the Pyrenean mountain range. The electrical resistivity distribution beneath the Central-Eastern Pyrenees was characterized by means of three-dimensional (3-D) joint inversion of three electromagnetic datasets: (1) the MT impedance tensor (Z), (2) the geomagnetic transfer function (T), and (3) the inter-station horizontal magnetic transfer function (H). The main finding was the non-continuity to the east of the major conductive anomaly observed previously beneath the Central and West-Central Pyrenees related to partial melting of the Iberian subducted lower crust. Lower amounts of water (related to the presence of muscovite and biotite) in the subducted lower crust beneath the Eastern Pyrenees were suggested to explain the lack of partial melting in this part of the mountain range. The electrical resistivity model also revealed higher electrical resistivity values for the lithospheric mantle beneath the Eastern Pyrenees than beneath the Central Pyrenees, thus supporting the hypothesis of an heterogeneous Iberian plate inherited from the Variscan Orogeny. A less clear signature was the lateral variation along the strike direction of the lithosphere-asthenosphere boundary beneath the Eastern Pyrenees (relatively flat, between 110 km and 140 km depth) and the Central Pyrenees (north dipping, between 80 km and 120 km depth beneath the Iberian Plate and between 110 km and 160 km depth beneath the European plate), supporting the hypothesis of a missing lithospheric root beneath the Eastern Pyrenees

Expected geomagnetically induced currents in the Spanish islands power transmission grids.

The aim of this study is to evaluate the geomagnetically induced current (GIC) hazard in the power networks of the Canary and Balearic archipelagos. This is done in order to strictly complete the detailed assessment at national level of the power transmission system of mainland Spain, including the 400 and 220 kV levels. We have constructed models for the grids in each of the individual systems and used resistivity models of the lithosphere for each group of islands, from which we have calculated the surface impedances. The respective models of electrical admittances of the grids have been combined with the geoelectric field derived from the convolution of the recorded (or expected in an extreme scenario) geomagnetic storms and the impedances calculated from the geoelectrical models to derive the expected GICs in the power lines, substations, and transformers. The low geomagnetic latitude of the Canary Islands combined with the small size of their power networks, makes them one of the least likely electrified locations to record significant GICs, with less than 3 A for the 100-year return period. Even the 13 A that could be reached for the upper limit of the 95% confidence interval at the 500-year return period does not seem likely to have a significant impact. The Balearic Islands, being at higher latitude and with a system length of approximately 300 km, including alternating current power lines connecting the Islands, shows GIC signals of moderate amplitude with up to 40 A for the 100-year return period.</p

A detailed model of the Irish High Voltage Power Network for simulating GICs

Constructing a power network model for geomagnetically induced current (GIC) calculations requires information on the DC resistances of elements within a network. This information is often not known, and power network models are simplified as a result, with assumptions used for network element resistances. Ireland's relatively small, isolated network presents an opportunity to model a complete power network in detail, using as much real‐world information as possible. A complete model of the Irish 400, 275, 220, and 110 kV network was made for GIC calculations, with detailed information on the number, type, and DC resistances of transformers. The measured grounding resistances at a number of substations were also included in the model, which represents a considerable improvement on previous models of the Irish power network for GIC calculations. Sensitivity tests were performed to show how calculated GIC amplitudes are affected by different aspects of the model. These tests investigated: (1) How the orientation of a uniform electric field affects GICs. (2) The effect of including/omitting lower voltage elements of the power network. (3) How the substation grounding resistances assumptions affected GIC values. It was found that changing the grounding resistance value had a considerable effect on calculated GICs at some substations and no discernible effect at others. Finally, five recent geomagnetic storm events were simulated in the network. It was found that heavy rainfall prior to the 26–28 August 2015 geomagnetic storm event may have had a measurable impact on measured GIC amplitudes at a 400/220 kV transformer ground

Modeling geoelectric fields in Ireland and the UK for space weather applications

Geoelectric fields at the Earth’s surface caused by geomagnetic storms have the potential to disrupt and damage ground-based infrastructure such as electrical power distribution networks, pipelines, and railways. Here we model geoelectric fields in Ireland and the UK during both quiet and active time intervals of geomagnetic conditions using measurements from magnetic observatories and electromagnetic tensor relationships. The analysis focused on (1) defining periods of the magnetic field variations that are largely affected by the geomagnetic storms, between 30 and 30,000 s; (2) constraining the electromagnetic tensor relationships that defines the Earth’s response to magnetic field variations; (3) implementing and validating two approaches for modeling geoelectric fields based on measurements from magnetic observatories and local and interstation electromagnetic transfer functions; and (4) estimating uncertainties when modeling geoelectric fields. The use of interstation tensor relationships allowed us to differentiate between regional and local geomagnetic sources. We found coherence values of 0.5–0.95, signal-to-noise ratio of 1–15 dB, normalized root-mean-square values of 0.8–3.4, and root-mean-square values of 0.7–84 mV/km. Within these ranges of values, sites in close proximity (<100 km) to a magnetic observatory and not affected by local storms will provide the most accurate results, while sites located at further distances and affected by spatially localized features of the storm will be less accurate. These methods enable us to more accurately model geomagnetically induced currents, and their associated uncertainties, in the British and Irish power networks