Erresonantzia kritikoen detekzioa zarata analisi bidez mikouhinetako anplifikadoreetan

[EUS] Gradu amaierako lan honetan zehar mikrouhinetako anplifikadoreen portaera eta errendimenduan hain kaltegarri diren erresonantzia kritikoak detektatzea izan du helburu. Horretarako, polo-zero identifikazioaren metodo alternatibo diren zarata aitzindariak aztertu izan dira. Testuinguru honetan, bi helburu nagusi izan ditugu: zarata aitzindari hauek detektatzeko neurketa sistema bat ahalik eta modu errealistenean simulatzea eta hauen detekzioa ahalbidetuko duten estrategiak aztertu eta garatzea

Use of portable devices and confocal Raman spectrometers at different wavelength to obtain the spectral information of the main organic components in tomatoes (Solanum Lycopersicum) fruits

Tomato (Solanum lycopersicum) fruit samples, in two ripening stages, ripe (red) and unripe (green), collected from a cultivar in the North of Spain (Barrika, Basque Country), were analyzed directly, without any sample pretreatment, with two different Raman instruments (portable spectrometer coupled to a micro-videocamera and a confocal Raman microscope), using two different laser excitation wavelengths (514 and 785 nm, only for the confocal microscope). The combined use of these laser excitation wavelengths allows obtaining, in a short period of time, the maximum spectral information about the main organic compounds present in this fruit. The major identified components of unripe tomatoes were cutin and cuticular waxes. On the other hand, the main components on ripe tomatoes were carotenes, polyphenoles and polysaccharides. Among the carotenes, it was possible to distinguish the presence of lycopene from b-carotene with the help of both excitation wavelengths, but specially using the 514 nm one, which revealed specific overtones and combination tones of this type of carotene.This work has been financially supported by Research Project S-PE11-UN128 of the Basque Country government. Technical and support provided by SGIker (UPV/EHU, MICINN, GV/EJ, ESF) is gratefully acknowledged

Anharmonicity Reveals the Tunability of the Charge Density Wave Orders in Monolayer VSe2

VSe2 is a layered compound that has attracted great attention due to its proximity to a ferromagnetic state that is quenched by its charge density wave (CDW) phase. In the monolayer limit, unrelated experiments have reported different CDW orders with different transition temperatures, making this monolayer very controversial. Here we perform first-principles nonperturbative anharmonic phonon calculations in monolayer VSe2 in order to estimate the CDW order and the corresponding transition temperature. They reveal that monolayer VSe2 develops two independent charge density wave orders that compete as a function of strain. Variations of only 1.5% in the lattice parameter are enough to stabilize one order or the other. Moreover, we analyze the impact of external Lennard-Jones interactions, showing that these can act together with anharmonicity to suppress the CDW orders. Our results solve previous experimental contradictions, highlighting the high tunability and substrate dependency of the CDW orders of monolayer VSe2.We acknowledge the computational resources provided by the CESGA and the Aalto Science-IT project. A.O.F. acknowledges the financial support received through the Academy of Finland Project No. 349696. J.D. thanks the Department of Education of the Basque Government for a predoctoral fellowship (Grant No. PRE-2020-1-0220). We thank the Ministry of Science and Education of Spain for financial support through the projects PGC2018-101334-A-C22, GC2018-101334-B-C21, PID2021-122609NB-C22. I.E. acknowledges funding from the Department of Education, Universities and Research of the Eusko Jaurlaritza, and the University of the Basque Country UPV/EHU (Grant No. IT1527-22)

Phonon collapse and van der Waals melting of the 3D charge density wave of VSe2_2

Among transition metal dichalcogenides (TMDs), VSe$_2$ is considered to develop a purely 3-dimensional (3D) charge-density wave (CDW) at T$_{CDW}$=110 K. Here, by means of high resolution inelastic x-ray scattering (IXS), we show that the CDW transition is driven by the collapse of an acoustic mode at the critical wavevector \textit{q}$_{CDW}$= (2.25 0 0.7) r.l.u. and critical temperature T$_{CDW}$=110 K. The softening of this mode starts to be pronounced for temperatures below 2$\times$ T$_{CDW}$ and expands over a rather wide region of the Brillouin zone, suggesting a large contribution of the electron-phonon interaction to the CDW formation. This interpretation is supported by our first principles calculations that determine a large momentum-dependence of the electron-phonon interaction, peaking at the CDW wavevector, in the presence of nesting. Fully anharmonic {\it ab initio} calculations confirm the softening of one acoustic branch at \textit{q}$_{CDW}$ as responsible for the CDW formation and show that van der Waals interactions are crucial to melt the CDW. Our work also highlights the important role of out-of-plane interactions to describe 3D CDWs in TMDs

Assessment of stress and nutritional biomarkers in cultured Octopus vulgaris paralarvae: Effects of geographical origin and dietary regime

The common octopus (Octopus vulgaris) is a promising species for aquaculture diversification, but massive mortality during the first life-cycle stages (paralarvae) is the main bottleneck for its commercial production in captivity. The aim of this study was to assess stress and nutritional condition biomarkers (HSP70, ROS enzymes and lipid peroxidation) (RNA/DNA, RNA/protein, protein/DNA and protein) inO.vulgarisparalarvae from different geographical origins and fed withArtemiaenriched with marine phospholipids or microalgae (control group). To this end paralarvae were cultured for 30days, in three different centres in Spain (Tarragona-Mediterranean area, Tenerife-Central Atlantic area and Vigo-North Atlantic area), under the same protocol, and fed onArtemiaenriched with marine phospholipids (LC60) (Marine Lecithin LC 60®, PhosphoTech Laboratoires) or microalgae (control group). Dry weight and most biomarkers analysed in hatchlings showed significant differences related to their origin (centre). Fifteen day old paralarvae presented significant differences in specific growth rate (SGR) associated with their dietary regime, and also showed differences in biomarkers associated both with their geographical origin and dietary regime. The results suggest that the SGR of paralarvae were positively influenced by LC60, promoting growth and in agreement with the results of nutritional condition biomarkers (nucleic acids ratios). The antioxidant defences against oxidative damage were also boosted in the LC60 paralarvae group, possibly as a result of the elevated content in highly polyunsaturated fatty acids. In addition, the partial correlations found between biomarkers varied according to diet. However, no positive effect of LC60 on survival was observed. The high variability found among geographical origins, despite the use of the same rearing protocol, highlights the need to clarify the sources of such variability

Electronic structure and lattice dynamics of 1T-VSe2_2: origin of the 3D-CDW

In order to characterize in detail the charge density wave (CDW) transition of 1$T$-VSe$_2$, its electronic structure and lattice dynamics are comprehensively studied by means of x-ray diffraction, angle resolved photoemission (ARPES), diffuse and inelastic x-ray scattering (IXS), and state-of-the-art first principles density functional theory calculations. Resonant elastic x-ray scattering (REXS) does not show any resonant enhancement at either V or Se K-edges, indicating that the CDW peak describes a purely structural modulation of the electronic ordering. ARPES identifies (i) a pseudogap at T$>$T$_{CDW}$, which leads to a depletion of the density of states in the $ML-M'L'$ plane at T$<$T$_{CDW}$, and (ii) anomalies in the electronic dispersion reflecting a sizable impact of phonons on it. A diffuse scattering precursor, characteristic of soft phonons, is observed at room temperature (RT) and leads to the full collapse of the low-energy phonon ($\omega_1$) with propagation vector (0.25 0 -0.3) r.l.u. We show that the frequency and linewidth of this mode are anisotropic in momentum space, reflecting the momentum dependence of the electron-phonon interaction (EPI), hence demonstrating that the origin of the CDW is, to a much larger extent, due to the momentum dependence EPI with a small contribution from nesting. The pressure dependence of the $\omega_1$ soft mode remains nearly constant up to 13 GPa at RT, with only a modest softening before the transition to the high-pressure monoclinic $C2/m$ phase. The wide set of experimental data are well captured by our state-of-the art first-principles anharmonic calculations with the inclusion of van der Waals (vdW) corrections in the exchange-correlation functional. The description of the electronics and dynamics of VSe$_2$ reported here adds important pieces of information to the understanding of the electronic modulations of TMDs

Meta‐analysis approach to the effects of live prey on the growth of Octopus vulgaris paralarvae under culture conditions

The common octopus (Octopus vulgaris, Cuvier 1797) is a promising species for aquaculture diversification, but the massive mortality during the first life stage is the main bottleneck for its commercial production. The aim of the present study was to compare the effects of different live preys (Artemia and crustacean zoeae) and/or Artemia enrichment protocols in the paralarval growth by using a meta‐analysis approach. A total of 26 independent assays were used, including data from the bibliography and from experiments carried out by our group. Three comparisons were established: (i) crustacean zoeae vs. Artemia, (ii) different crustacean zoeae species and (iii) Artemia enriched with marine lecithin (rich in polar lipids‐PL and docosahexaenoic acid‐DHA) vs. previously used Artemia enrichments. The meta‐analysis approach allowed a quantitative review of independent studies with reliable conclusions, avoiding the subjectivity inherent to classical reviews. The outputs provided statistical confirmation of the better suitability of crustacean zoeae with respect to Artemia. However, not all crustacean species showed the same results, given that the high variability on Grapsus zoeae hampered finding significant differences with respect to the control treatment (Artemia). Nutrient composition and biometry of the different types of prey are discussed as possible causes of the differences arising from the meta‐analysis. Finally, the present results suggest that marine lecithin has a beneficial effect on paralarval growth with respect to previously used enrichments, which could be related to the increase in DHA and PL in Artemia, given the essential role of these lipid components in octopus paralarval physiology.info:eu-repo/semantics/acceptedVersio

Un meta-análisis sobre el crecimiento de las paralarvas de pulpo común (Octopus vulgaris) alimentadas con diferentes presas vivas

El objetivo del presente estudio fue comparar el efecto de la alimentación con diferentes presas vivas (Artemia y zoeas de crustáceos) y/o Artemia enriquecida, sobre el crecimiento de paralarvas de pulpo común (Octopus vulgaris) a través de un meta-análisis. Se usaron un total de 26 ensayos independientes para analizar las diferencias en crecimiento entre: (i) zoeas de crustáceos vs Artemia, (ii) diferentes especies de crustáceos y (iii) Artemia enriquecida con fosfolípidos marinos vs otros enriquecedores de Artemia. Se observó un mejor crecimiento de las paralarvas alimentadas con zoeas de crustáceos vs Artemia. Sin embargo, no todas las zoeas mostraron los mismos resultados, dada la alta variabilidad observada con el género Grapsus que impidió que se pudieran apreciar diferencias respecto a la Artemia usada como control. Finalmente, el enriquecimiento de Artemia con fosfolípidos marinos mejoró el crecimiento de las paralarvas, lo cual podría estar relacionado con el incremento en los niveles del ácido docosahexaenoico ((DHA, 22:6n-3) y de los lípidos polares en Artemia

Un meta-análisis sobre el crecimiento de las paralarvas de pulpo común (Octopus vulgaris) alimentadas con diferentes presas vivas

El objetivo del presente estudio fue comparar el efecto de la alimentación con diferentes presas vivas (Artemia y zoeas de crustáceos) y/o Artemia enriquecida, sobre el crecimiento de paralarvas de pulpo común (Octopus vulgaris) a través de un meta-análisis. Se usaron un total de 26 ensayos independientes para analizar las diferencias en crecimiento entre: (i) zoeas de crustáceos vs Artemia, (ii) diferentes especies de crustáceos y (iii) Artemia enriquecida con fosfolípidos marinos vs otros enriquecedores de Artemia. Se observó un mejor crecimiento de las paralarvas alimentadas con zoeas de crustáceos vs Artemia. Sin embargo, no todas las zoeas mostraron los mismos resultados, dada la alta variabilidad observada con el género Grapsus que impidió que se pudieran apreciar diferencias respecto a la Artemia usada como control. Finalmente, el enriquecimiento de Artemia con fosfolípidos marinos mejoró el crecimiento de las paralarvas, lo cual podría estar relacionado con el incremento en los niveles del ácido docosahexaenoico ((DHA, 22:6n-3) y de los lípidos polares en Artemia

EFECTO DE LOS FOSFOLÍPIDOS MARINOS SOBRE BIOMARCADORES NUTRICIONALES Y DE ESTRÉS FISIOLÓGICO DE LAS PARALARVAS DEL PULPO COMÚN (OCTOPUS VULGARIS) BAJO CONDICIONES DE CULTIVO ESTANDARIZADAS EN TRES CENTROS

El efecto del enriquecimiento de la Artemia con fosfolípidos marinos (LC60), sobre el crecimiento, la supervivencia y los biomarcadores de condición nutricional (ARN/ADN) y de estrés fisiológico (proteínas de estrés (HSP70), enzimas antioxidantes y peroxidación lipídica) en paralarvas cultivadas de pulpo común (Octopus vulgaris) se evaluó bajo un protocolo estandarizado en tres centros. Las paralarvas recién eclosionadas mostraron diferencias significativas entre centros en peso seco y en la mayor parte de los biomarcadores analizados. Por el contario, en paralarvas cultivadas de 15 días, se encontraron diferencias significativas debidas a la dieta, presentando un incremento en la tasa de crecimiento específica (TCE) en el grupo alimentado con Artemia enriquecida con LC60 y mayores niveles de actividad GPX T y GR. Sin embargo, la dieta no tuvo efecto en la supervivencia de las paralarvas. Los biomarcadores de condición nutricional y de estrés fisiológicos presentaron diferencias entre los centros. Los resultados indican que el uso de fosfolípidos marinos como enriquecimiento de Artemia mejora el crecimiento de las paralarvas, si bien no se observa un efecto positivo de dicho tratamiento sobre la supervivencia de las mismas