Estructures supramoleculars amb propietats luminescents. Estudis de reconeixement molecular

Treballs Finals de Grau de Química, Facultat de Química, Universitat de Barcelona, Any: 2016, Tutor: Laura Rodríguez RaurellSupramolecular fluorescent chemosensors in water are very appealing because luminescence exhibits low detection limits and a high selectivity. Macrocyclic structures with polydentate nitrogen ligands represent a fundamental and extensive type of compounds in this group. The strategy employed in this work consists on the connection of the central amine to a naphtalene group (chromophore) and to two pyridine moieties at the end positions, to be involved in self-assembly processes giving rise to metallomacrocyclic structures. These systems can be used in molecular recognition processes. The encapsulation of the metallomacrocycles on hydrogels facilitates the use of the chemosensors in daily life applications. Furthermore, these type of compounds gives stability to the hydrogels and also photophysical acquired properties. In addition, the use of these polydentate nitrogen ligands in order to synthesize new silver and gold containing compounds, provide new tools for the recognition and/or encapsulation of molecules. Due to these properties, a synthetic way has been assayed, in order to obtain supramolecular cages with luminescent propertie

Niche divergence and limits to expansion in the high polyploid Dianthus broteri complex

Niche evolution in plant polyploids remains controversial and evidence for alternative patterns has been reported. Using the autopolyploid Dianthus broteri complex (2×, 4×, 6× and 12×) as a model, we aimed to integrate three scenarios – competitive exclusion, recurrent origins of cytotypes and niche filling – into a single framework of polyploid niche evolution. We hypothesized that high polyploids would tend to evolve towards extreme niches when low ploidy cytotypes have nearly filled the niche space. We used several ecoinformatics and phylogenetic comparative analyses to quantify differences in the ecological niche of each cytotype and to evaluate alternative models of niche evolution. Each cytotype in this complex occupied a distinct ecological niche. The distributions were mainly constrained by soil characteristics, temperature and drought stress imposed by the Mediterranean climate. Tetraploids had the highest niche breadth and overlap due to their multiple origins, whereas the higher ploidy cytotypes were found in different, restricted, nonoverlapping niches. Niche evolution analyses suggested a scenario with one niche optimum for each ploidy, including the two independent tetraploid lineages.Our results suggest that the fate of nascent polyploids could not be predicted without accounting for phylogenetic relatedness, recurrent origins or the niche occupied by ancestors.Aridos La Melera S.L. (FIUS project 2234/0724

Plasma enhanced terahertz rectification and noise in InGaAs HEMTs

In this work we explore high frequency collective phenomena present in InGaAs HEMTs which lead to a peak in the current noise spectrum and enhance their DC response to THz signals, thus originating a resonance in the rectification of AC signals. These phenomena have been evidenced in recent experiments, in which THz detection as a result of plasma wave resonances has been demonstrated. In this paper, by means of Monte Carlo simulations, the noise spectra and the AC to DC rectification properties of the devices have been calculated and linked to the properties of the plasma oscillations within two distinct parts of the source-gate region: the capped and the recessed sections of the channel.ROOTHz (FP7-243845

Polyploidy promotes divergent evolution across the leaf economics spectrum and plant edaphic niche in the Dianthus broteri complex

The evolution of the leaf economics spectrum (LES) is known to be constrained by genetic relatedness but also promoted at small geographical and phylogenetic scales. In those cases, we hypothesized that polyploidy would play a prominent role as an outstanding source of functional divergence and adaptive potential. We registered leaf-level nutrient, water- and light-economy-related traits from the LES as well as edaphic properties in the four cytotypes of the autopolyploid Dianthus broteri complex (2×, 4×, 6× and 12×). We analysed the effect of ploidy level on the integration of the LES network, checked if concerted evolution occurred between LES and soil niche and tested the influence of phylogeny on the variables. Alternative evolutionary models for both sets of traits were compared. We found higher divergence of polyploids (especially 6× and 12×) compared to diploids in the LES and soil niche, but these traits are not coevolving. 6× and 12× showed opposite ecological strategies regarding resource use and higher uncoupling of the LES network. Early divergence of traits prevailed in both LES and edaphic niche (supported by better fitted evolutionary models with one optimum per cytotype), but post-polyploidization processes played an important role for the photochemical behaviour. Synthesis. Our results indicated shifts in ecological strategies across Dianthus broteri cytotypes and suggested a powerful role of polyploidy in overcoming constraints for the evolution of plant functional traits.PGC2018-098358-B-I00 from the Spanish MICINNÁridos La Melera S.L. (FIUS project 2234/0724

Submillimeter-Wave Oscillations in Recessed InGaAs/InAlAs Heterostructures: Origin and Tunability

By means of an ensemble Monte Carlo simulator, the appeareance of THz oscillations in InAlAs/InGaAs slot diodes is predicted when the applied bias exceeds the threshold for intervalley transfer. Such high frequency is attained by the presence of a Gunn-like effect in the recess-to-drain region of the device channel whose dynamics is controlled by ballistic gamma valley electrons. In this work we explain the mechanism at the origin of this effect and also the influence of the bias conditions, delta-doping, recess-to-drain distance and recess length on the frequency of the ultra-fast Gunn like oscillations. The simulations show that a minimum value for the delta-doping is necessary to have enough carrier concentration under the recess and allow the oscillations to emerge. Finally, we show that shortening the devices (small recess and recess-to-drain lengths) increases of the oscillation frequency, so providing an interesting frequency tuneability of this THz source.ROOTHz (FP7-243845

El papel de las ciudades medias de interior en el desarrollo regional. El caso de Andalucía

Las ciudades medias presentan ventajas frente a las grandes urbes y, por ello, deberían desempeñar funciones esenciales para el equilibrio territorial. Sin embargo, en los últimos tiempos, las Administraciones Públicas han destinado más inversiones a las grandes metrópolis, provocando una concentración demográfica, económica, de infraestructuras y equipamientos en éstas, con la consiguiente pérdida del protagonismo que las ciudades medias tenían décadas atrás. En el presente artículo se establecen tipologías de ciudades medias andaluzas en función de su localización para evaluar su evolución en los últimos tiempos.Mid-size towns and cities have certain advantages over large cities and ought to play essential roles in spatial balance. However, in recent times the Public Administration has allocated more investments to large metropolises, leading to demographic, economic and infrastructural and equipment concentration in these, and mid-size towns and cities consequently relinquishing the leadership that they used to have several decades ago. This article discusses some of the main types of Andalusian mid-size towns and cities on the basis of their location and the different ways that they have developed in recent times

Learning Moore-Penrose based residuals for robust non-blind image deconvolution

This work was supported by grants P20_00286 and B-TIC-324-UGR20 funded by Consejería de Universidad, Investigación e Innovación ( Junta de Andalucía ) and by “ ERDF A way of making Europe”. Funding for open access charge: Universidad de Granada / CBUA.This paper proposes a deep learning-based method for image restoration given an inaccurate knowledge of the degradation. We first show how the impulse response of a Wiener filter can approximate the Moore-Penrose pseudo-inverse of the blur convolution operator. The deconvolution problem is then cast as the learning of a residual in the null space of the blur kernel, which, when added to the Wiener restoration, will satisfy the image formation model. This approach is expected to make the network capable of dealing with different blurs since only residuals associated with the Wiener filter have to be learned. Artifacts caused by inaccuracies in the blur estimation and other image formation model inconsistencies are removed by a Dynamic Filter Network. The extensive experiments carried out on several synthetic and real image datasets assert the proposed method's performance and robustness and demonstrate the advantage of the proposed method over existing ones.Junta de Andalucía P20_00286, B-TIC-324-UGR20ERDF A way of making EuropeUniversidad de Granada / CBU

Dynamic Monte Carlo study of isolated-gate InAs/AlSb HEMTs

In this work, by means of Monte Carlo simulations, the static and dynamic behavior of isolated-gate InAs/AlSb high electron mobility transistors (Sb-HEMTs) has been studied and compared with experimental results. The influence of the existence of a native oxide under the gate, the value of the surface charges in the gate recess and the possible variation of electron sheet carrier density, ns, has been studied. A decrease in the gate-source capacitance, transconductance and intrinsic cut-off frequency is observed because of the presence of the native oxide, while changes in the value of the surface charges in the recess only introduce a threshold voltage shift. The increase of ns shifts the maximum of the transconductance and intrinsic cut-off frequency to higher values of drain current and improves the agreement with the experimental results.ROOTHz (FP7-243845

Monte Carlo study of the noise performance of isolated-gate InAs/AlSb HEMTs

In this work, the extrinsic dynamic behaviour and noise performance of a 225 nm isolated-gate InAs/AlSb HEMT have been studied by means of Monte Carlo simulations. A very good agreement with experimental results has been achieved for fT. Discrepancies between experimental and simulated fmax have been observed and attributed to the experimental frequency dispersion of gd and Cds. The simulations of the intrinsic and extrinsic noise parameters indicate an excellent performance for this device (Fmin=0.3 dB@10 GHz) even if we confirm that the presence of the native oxide under the gate induces an significant decrease in fT and fmax of around 20%, together with an increase of noise figure and noise resistance.ROOTHz (FP7-243845

Monte Carlo Analysis of the Dynamic Behavior of InAlAs/InGaAs Velocity Modulation Transistors: A Geometrical Optimization

The influence of the geometry on the dynamic behavior of InAlAs/InGaAs velocity modulation transistors is analyzed by means of a Monte Carlo simulator in order to optimize the performance of this new type of transistor. In velocity modulation transistors, based on the topology of a double-gate high electron mobility transistor, the source and drain electrodes are connected by two channels with different mobilities, and electrons are transferred between both of them by changing the gate voltages in differential mode. Consequently, the drain current is modulated while keeping the total carrier density constant, thus in principle avoiding capacitance charging/discharging delays. However, the low values taken by the transconductance, as well as the high capacitance between the two gates in differential-mode operation, lead to a deficient dynamic performance. This behavior can be geometrically optimized by increasing the mobility difference between the two channels, by increasing the channel width and, mainly, by reducing the gate length, with a higher immunity to short channel effects than the traditional architectures.ROOTHz (FP7-243845