Understanding/unravelling carotenoid excited singlet states.

Carotenoids are essential light-harvesting pigments in natural photosynthesis. They absorb in the blue–green region of the solar spectrum and transfer the absorbed energy to (bacterio-)chlorophylls, and thus expand the wavelength range of light that is able to drive photosynthesis. This process is an example of singlet–singlet excitation energy transfer, and carotenoids serve to enhance the overall efficiency of photosynthetic light reactions. The photochemistry and photophysics of carotenoids have often been interpreted by referring to those of simple polyene molecules that do not possess any functional groups. However, this may not always be wise because carotenoids usually have a number of functional groups that induce the variety of photochemical behaviours in them. These differences can also make the interpretation of the singlet excited states of carotenoids very complicated. In this article, we review the properties of the singlet excited states of carotenoids with the aim of producing as coherent a picture as possible of what is currently known and what needs to be learned

Intermediate Seyfert: optical spectroscopic characteristics

Active Galactic Nuclei (AGN) are a particular class of galaxies characterized by a pretty luminous central region produced by an accreting disk. According to the Unified Model (UM) around this central structure we can recognize three regions: the Broad-Line Region (BLR) characterized by high velocity clouds, the Narrow-Line Region (NLR) with small velocity clouds, and the obscuring torus (Antonucci, 1993). The last component is fundamental in explaining the differences between AGN. According to the angle between the orientation of the torus and the observer we can find Seyfert 1 (Sy1), Seyfert 1.2/1.5/1.8/1.9 (IS), and Seyfert 2 (Sy2) galaxies (Khachikian & Weedman, 1974; Osterbrock, 1981). The second group defines what are called Intermediate Seyfert galaxies, in which both the NLR and the BLR can be seen due to the inclination. This work is focused on this kind of AGN, often ignored and never extensively studied as a class. Indeed, most of the studies tend to include them in the type 1/2 classification, causing a clear pollution of the analyzed samples. In addition, in some cases IS can be confused with Narrow-Line Seyfert 1 (NLS1). Obviously this is an effect of the composite profile of the Balmer lines, that makes difficult to easily or automatically separate IS from the other types. The aim of this work is to explore the spectroscopic characteristics of IS that could allow to define criteria to isolate them in a generic sample fo AGN. In addition, studying their properties could confirm the UM or on the contrary give new insights in the AGN structure, suggesting for example the existence of irregular emission from the accretion disk. The study is divided in: Chapter 1 introduction on AGN and Seyfert galaxies; Chapter 2 presentation of the sample, data analysis, fitting procedure, and physical outcomes; Chapter 3 conclusions and future work.The aim of this work is to obtain some optical characteristics of intermediates galaxies in order to distinguish them from NLS1 or to include them in the samples without polluting the scientific analysis. The work is divided as follow: Chapter 1 with an introduction on AGNs and Seyfert properties in the different bands, Chapter 2 a presentation of the selected sample and some general characteristics, Chapter 3 with the data analysis, in particular fittings and line ratios, Chapter 4 with the classification and discussion.Active Galactic Nuclei (AGN) are a particular class of galaxies characterized by a pretty luminous central region produced by an accreting disk. According to the Unified Model (UM) around this central structure we can recognize three regions: the Broad-Line Region (BLR) characterized by high velocity clouds, the Narrow-Line Region (NLR) with small velocity clouds, and the obscuring torus (Antonucci, 1993). The last component is fundamental in explaining the differences between AGN. According to the angle between the orientation of the torus and the observer we can find Seyfert 1 (Sy1), Seyfert 1.2/1.5/1.8/1.9 (IS), and Seyfert 2 (Sy2) galaxies (Khachikian & Weedman, 1974; Osterbrock, 1981). The second group defines what are called Intermediate Seyfert galaxies, in which both the NLR and the BLR can be seen due to the inclination. This work is focused on this kind of AGN, often ignored and never extensively studied as a class. Indeed, most of the studies tend to include them in the type 1/2 classification, causing a clear pollution of the analyzed samples. In addition, in some cases IS can be confused with Narrow-Line Seyfert 1 (NLS1). Obviously this is an effect of the composite profile of the Balmer lines, that makes difficult to easily or automatically separate IS from the other types. The aim of this work is to explore the spectroscopic characteristics of IS that could allow to define criteria to isolate them in a generic sample fo AGN. In addition, studying their properties could confirm the UM or on the contrary give new insights in the AGN structure, suggesting for example the existence of irregular emission from the accretion disk. The study is divided in: Chapter 1 introduction on AGN and Seyfert galaxies; Chapter 2 presentation of the sample, data analysis, fitting procedure, and physical outcomes; Chapter 3 conclusions and future work

Gestión de la explotación de percebe (Pollicipes Pollicipes) en la Reserva Natural de Berlengas (Portugal): evaluación del tope de capturas y talla mínima

The stalked barnacle Pollicipes pollicipes (Gmelin, 1790) is an important shellfish resource in Portugal. Due to the social-economic importance of barnacle harvesting, a management plan aimed at achieving a controlled and sustainable activity (including temporal and spatial closures, rotational harvesting, a limited number of harvesting licenses, bag and size limits for catches and catch reporting) was implemented in 2000 at the Berlengas Nature Reserve (RNB) in central Portugal. We evaluated the bag and size limits imposed by the management plan, performing observations on harvesting activity and asking licensed harvesters and RNB staff about these measures. Both inquiries and observations suggest that licensed harvesters are not following the bag and size limits imposed. Mean amounts captured in RNB varied from 14 to 24 kg per harvester/day, but 25% of the observations corresponded to higher catches per individual than the total amount allowed (20 kg). Only half of the sampled amounts (taken in autumn 2005 and 2006) were in agreement with the size limit regulation and 50% of the total biomass comprised individuals of maximal rostro-carinal length (RC) ≥ 25 mm. For most harvesters, size limit is the most difficult management rule to fulfil. Both harvesters and RNB staff agree that surveillance is scarce and is a major problem of this fishing activity. In order to achieve a more sustainable use of this resource, we propose the implementation of a more effective surveillance and monitoring plan, the definition of a unique landing site, the maintenance of the bag limit (20 kg) and a reduction of the size limit (50% of total biomass comprising individuals ≥ 22 mm RC).El percebe Pollicipes pollicipes (Gmelin, 1790) es un recurso importante en Portugal. Debido a la importancia socioeconómica de la recolección de percebes y con objeto de alcanzar una actividad controlada y sostenible, se implementó en 2000 en la Reserva Natural de Berlengas (RNB; centro de Portugal) un plan de gestión para regular esta actividad (incluyendo el cierre temporal y espacial, rotación de la explotación, número limitado de licencias, topes de captura individual y talla mínima). Hemos evaluado los topes de captura y la talla mínima impuestos por el plan de gestión, realizando observaciones sobre la actividad de recolección y realizando encuestas a perceberos y personal de la RNB sobre tales medidas. Los perceberos no están siguiendo los topes de captura y los límites de tamaño establecidos. Las cantidades medias capturadas en la RNB han variado de 14 a 24 kg por mariscador/día, pero el 25% de las observaciones corresponden a las capturas por persona superior al importe total permitido (20 kg). Sólo la mitad de las muestras (tomadas en el otoño de 2005 y 2006) se mostró de acuerdo con el reglamento de límite de tamaño (50% de la biomasa total que incluye percebes de un máximo de longitud rostro-carinal RC ≥ 25 mm). Para la mayoría de los marisca- dores, el límite de tamaño es la norma de gestión más difícil de cumplir. Con el fin de alcanzar un uso más sostenible de este recurso, se propone la implantación de un plan de monitorización y vigilancia más eficaz, la definición de un único lugar de descarga, el mantenimiento del tope de captura individual (20 kg) y la reducción de la regulación de talla mínima (50% de la biomasa total compuesto por individuos ≥ 22 mm RC)

An algorithmic framework for synthetic cost-aware decision making in molecular design

Small molecules exhibiting desirable property profiles are often discovered through an iterative process of designing, synthesizing, and testing sets of molecules. The selection of molecules to synthesize from all possible candidates is a complex decision-making process that typically relies on expert chemist intuition. We propose a quantitative decision-making framework, SPARROW, that prioritizes molecules for evaluation by balancing expected information gain and synthetic cost. SPARROW integrates molecular design, property prediction, and retrosynthetic planning to balance the utility of testing a molecule with the cost of batch synthesis. We demonstrate through three case studies that the developed algorithm captures the non-additive costs inherent to batch synthesis, leverages common reaction steps and intermediates, and scales to hundreds of molecules. SPARROW is open source and can be found at http://github.com/coleygroup/sparrow

Photon-based and classical descriptions in nanophotonics: a review

The centrality of the photon concept in modern physics is strongly evident in wide spheres of photonics and nanophotonics. Despite the resilience and persistence of earlier classical representations, there are numerous optical features and phenomena that only truly photon-based descriptions of theory can properly address. It is crucial to cast theory in terms of observables, and in this respect the quantum theory of light engages most directly and pragmatically with experiment. No other theory adequately reconciles the discreteness in energy of optical quanta, with their characteristic quantum mechanical delocalization in space. Examples of the distinctiveness of a photonic representation are to be found in nonclassical optical correlations; intensity fluctuations and phase; polarization, spin, and information content; measures of optical chirality; near-field interactions; and plasmonics. Increasingly, links between these fundamental properties and features are proving significant in the context of nanoscale interactions. Yet, even as new technologies are being built on the framework of modern photonics, a number of difficult questions surrounding the nature of the photon still remain. Both in its flourishing applications and in matters of fundamental entity, the photon is still a subject very much at the heart of current research