Revisión de literatura de jerarquía volúmenes acotantes enfocados en detección de colisiones

(Eng) A bounding volume is a common method to simplify object representation by using the composition of geometrical shapes that enclose the object; it encapsulates complex objects by means of simple volumes and it is widely useful in collision detection applications and ray tracing for rendering algorithms. They are popular in computer graphics and computational geometry. Most popular bounding volumes are spheres, Oriented-Bounding Boxe s (OBB’ s), Axis-Align ed Bound ing Boxes (AABB’ s); moreover , the literature review includes ellipsoids, cylinders, sphere packing, sphere shells , k-DOP’ s, convex hulls, cloud of points, and minimal bounding boxe s, among others. A Bounding Volume Hierarchy is ussualy a tree in which the complete object is represented thigter fitting every level of the hierarchy. Additionally, each bounding volume has a cost associated to construction, update, and interference te ts. For instance, spheres are invariant to rotation and translations, then they do not require being updated ; their constructions and interference tests are more straightforward then OBB’ s; however, their tightness is lower than other bounding volumes. Finally , three comparisons between two polyhedra; seven different algorithms were used, of which five are public libraries for collision detection.(Spa) Un volumen acotante es un método común para simplificar la representación de los objetos por medio de composición de formas geométricas que encierran el objeto; estos encapsulan objetos complejos por medio de volúmenes simples y son ampliamente usados en aplicaciones de detección de colisiones y trazador de rayos para algoritmos de renderización. Los volúmenes acotantes son populares en computación gráfica y en geometría computacional; los más populares son las esferas, las cajas acotantes orientadas (OBB’s) y las cajas acotantes alineadas a los ejes (AABB’s); no obstante, la literatura incluye elipses, cilindros empaquetamiento de esferas, conchas de esferas, k-DOP’s, convex hulls, nubes de puntos y cajas acotantes mínimas, entre otras. Una jerarquía de volúmenes acotantes es usualmente un árbol, en el cual la representación de los objetos es más ajustada en cada uno de los niveles de la jerarquía. Adicionalmente, cada volumen acotante tiene asociado costos de construcción, actualización, pruebas de interferencia. Por ejemplo, las esferas so invariantes a rotación y translación, por lo tanto no requieren ser actualizadas en comparación con los AABB no son invariantes a la rotación. Por otro lado la construcción y las pruebas de solapamiento de las esferas son más simples que los OBB’s; sin embargo, el ajuste de las esferas es menor que otros volúmenes acotantes. Finalmente, se comparan dos poliedros con siete algoritmos diferentes de los cuales cinco son librerías públicas para detección de colisiones

Results from Bottom Trawl Survey on Flemish Cap of June-July 2017

A stratified random bottom trawl survey on Flemish Cap was carried out from June 16th to July 15th 2017. The area surveyed was extended up to depths of 800 fathoms (1460 meters) following the same procedures as in previous years and 181 fishing stations planned. The survey was carried out by the R/V Vizconde de Eza with the usual survey gear (Lofoten). A total of 181 valid hauls were made by the vessel R/V Vizconde de Eza, 120 up to 730 meters depth and 61 up to 1460 meters. Survey results including abundance indices of the main commercial species and age distributions for American plaice, Greenland halibut, roughhead grenadier and shrimp are presented. Cod and redfish age distributions are not available for 2017 due to administrative problems. The general indexes for this year are estimated taken into account the traditional swept area (strata 1-19, up to depths of 730 m.) and the total area surveyed (strata 1-34, up to depths of 1460 m.).Versión del editor

First recorded case of leucism in the velvet belly lantern shark Etmopterus spinax (Squaliformes: Etmopteridae)

The capture of a female specimen of the velvet belly lantern shark Etmopterus spinax with abnormal skin coloration is reported. The specimen was captured off northern Spain (Bay of Biscay, North-eastern Atlantic) in 2021 by bottom trawling. The lack of dermal melanophores combined with a normal retinal pigmentation, lead us to considerate the specimen as leucistic. This is the first case of leucism in E. spinax and the second record of colour aberration in the family Etmopteridae. A comprehensive updated review of published literature on albinism and leucism in chondrichthyans is also provided.En prens

First recorded case of leucism in the velvet belly lantern shark Etmopterus spinax (Squaliformes: Etmopteridae)

Poster presentado en el SIBIC 2022 IX Iberian Congress of IchthyologyThe capture of a female specimen of the velvet belly lantern shark Etmopterus spinax with abnormal skin coloration is reported. The specimen was captured off northern Spain (Bay of Biscay, North-Eastern Atlantic) in 2021 by bottom trawling. The lack of dermal melanophores combined with a normal retinal pigmentation, lead us to considérate the specimen as leucistic. This is the first case of leucism in E. spinax and the second record of colour aberration in the family Etmopteridae

Effect of different quality irrigation water on the growth, mineral concentration and physiological parameters of Viburnum tinus plants

Treated wastewater may be considered an alternative source of water and fertilizer nutrients for landscape plants. However, NaCl, the principal compound in this water, can be detrimental to plants. Viburnum tinus plants were submitted for 4 months to 4 irrigation treatments with water from different sources: control (Control) (EC < 0.9 dS m-1); NaCl solution (NaCl) (EC = 4 dS m-1); irrigation water normally used in the area (IW) (EC = 1.2-1.8 dS m-1) and reclaimed water (RW) (EC = 4 dS m-1). During a recovery period of two months, all the plants were irrigated with the control water. The results showed that biomass was affected in NaCl, IW and RW treatments, both leaf area and height decreased at the end of saline period. These changes were more pronounced in the NaCl treatment, which also caused a decrease in stem diameter and root/shoot ratio. The similar growth alterations founded after the recovery period showed that salts continued to be present in the substrate. Compared with the control, NaCl and RW plants showed a greater rate of Na+ and Cl- absorption by roots. Stem water potential was mainly affected by the NaCl treatment in the last weeks of the saline period. Through the experiment, the stomatal conductance and photosynthesis values were the lowest in plants that received the highest amount of salts, especially NaCl treatment which was the only treatment that did not recover at the end of experiment. Plants of the IW treatment showed slight changes in stomatal conductance and photosynthetic rate with respect to the control, although the reduction in the growth and size of these plants suggests that slight increases in EC could be very toxic for this species. Hence, using different sources of water with similar EC, (NaCl and RW) it is important to know the exact composition, since the toxic effects produced by high concentrations of Na+ and Cl- might be offset by the effect of other ions like magnesium, potassium and phosphorus. In the physicochemical analysis of water, the highest concentrations of these ions were observed in RW and as consequence, their concentrations in plants were not reduced by the Na+ and Cl- effect, phosphorus even increased, improving the plant nutritional balance.This work was supported by the projects: CICYT (AGL 2008- 05258-CO2-1-2- AGR and AGL 2011-30022-CO2-01-02), Fundación Séneca (15356/PI/10) and Vías y Construcción, S. A. (CDTI IDI-20101191).Peer Reviewe

Total ozone column derived from GOME and SCIAMACHY using KNMI retrieval algorithms: Validation against Brewer measurements at the Iberian Peninsula

This article focuses on the validation of the total ozone column (TOC) data set acquired by the Global Ozone Monitoring Experiment (GOME) and the Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY) satellite remote sensing instruments using the Total Ozone Retrieval Scheme for the GOME Instrument Based on the Ozone Monitoring Instrument (TOGOMI) and Total Ozone Retrieval Scheme for the SCIAMACHY Instrument Based on the Ozone Monitoring Instrument (TOSOMI) retrieval algorithms developed by the Royal Netherlands Meteorological Institute. In this analysis, spatially colocated, daily averaged ground-based observations performed by five well-calibrated Brewer spectrophotometers at the Iberian Peninsula are used. The period of study runs from January 2004 to December 2009. The agreement between satellite and ground-based TOC data is excellent (R2 higher than 0.94). Nevertheless, the TOC data derived from both satellite instruments underestimate the ground-based data. On average, this underestimation is 1.1% for GOME and 1.3% for SCIAMACHY. The SCIAMACHY-Brewer TOC differences show a significant solar zenith angle (SZA) dependence which causes a systematic seasonal dependence. By contrast, GOME-Brewer TOC differences show no significant SZA dependence and hence no seasonality although processed with exactly the same algorithm. The satellite-Brewer TOC differences for the two satellite instruments show a clear and similar dependence on the viewing zenith angle under cloudy conditions. In addition, both the GOME-Brewer and SCIAMACHY-Brewer TOC differences reveal a very similar behavior with respect to the satellite cloud properties, being cloud fraction and cloud top pressure, which originate from the same cloud algorithm (Fast Retrieval Scheme for Clouds from the Oxygen A-Band (FRESCO+)) in both the TOSOMI and TOGOMI retrieval algorithms.This work was partially supported by the Andalusian Regional Government through projects P08‐RNM ‐3568 andP10‐RNM‐6299, the Spanish Ministry of Science and Technology throughprojects CGL2010–18782 and CSD2007–00067, and the European Unionthrough ACTRIS project (EU INFRA‐2010‐1.1.16‐262254)

Catches of tropical fish species in Galician Atlantic waters (north-west Iberian Peninsula)

In the present paper, the authors list the tropical fish species recorded in Galician Atlantic waters during 1996-1997: Hoplostethus cadenati Quéro, 1974; Neoscopelus macrolepidotus Johnson, 1863; Nettastoma melanura Rafinesque, 1810; Halosaurus ovenii Johnson, 1863; Cyttopsis roseus (Lowe, 1843); Chaunax pictus Lowe, 1846; Caranx crysos (Mitchill, 1815); Pseudocaranx dentex (Blochampersand Schneider in Schneider 1801) and Dasyatis violacea (Bonaparte, 1832). They also review the distribution of these species in the east Atlantic, and briefly describe some of the specimens captured. The captures of Dasyatis violacea, Neoscopelus macrolepidotus and Nettastoma melanura are the first records of these species in Galician Atlantic waters. The new record for Galician waters of Neoscopelus macrolepidotus also indicates a new northern limit for this species in the northeast Atlantic.En el presente trabajo se recoge la captura de especies de afinidades tropicales presentes en aguas atlánticas de Galicia durante 1996-1997: Hoplostethus cadenati Quéro, 1974; Neoscopelus macrolepidotus Johnson, 1863; Nettastoma melanura Rafinesque, 1810; Halosaurus ovenii Johnson, 1863; Cyttopsis roseus (Lowe, 1843); Chaunax pictus Lowe, 1846; Caranx crysos (Mitchill, 1815); Pseudocaranx dentex (Blochampersand Schneider en Sceneider, 1801) y Dasyatis violacea (Bonaparte, 1832). Se realiza una revisión de su distribución en el Atlántico este y una breve descripción de algunos de los ejemplares capturados. Las capturas de Dasyatis violacea, Neoscopelus macrolepidotus y Nettastoma melanura en aguas atlánticas de Galicia constituyen primeras citas en el área estudiada. Además, la presencia de Neoscopelus macrolepidotus en el talud continental de Galicia, extiende hacia el norte su área de distribución en el nordeste atlántico.Instituto Español de Oceanografí

Living at the top. Connectivity limitations and summit depth drive fish diversity patterns in an isolated seamount

The fish assemblages of the Galicia Bank and the closest continental slope (northwest of Spain) were analysed using otter trawls to improve our understanding of how environmental drivers structure seamount fish communities in the deep sea. The effect of environmental drivers on these assemblages was studied using multivariate techniques together with the variation in α and β diversity across assemblages. Fish fauna in the study area was distributed in 5 different assemblages generated by the action of 3 main drivers: depth, distance to the coast and presence of cold-water corals. The observed differences in species composition among assemblages were mostly explained by species turnover across a depth gradient. The seamount summit and the continental slope showed important differences despite sharing similar depths, mainly because several species requiring shallow juvenile habitats were absent from the summit. These absences were observed in both summit assemblages inside and outside the cold-water coral reef. Our results show that in isolated seamounts with relatively deep summits, the lack of connectivity with shallower areas limits the presence of certain species, probably due to the impossibility for these species to migrate directly from shallow to deeper seabed areas. These species are replaced by species with preferences for deeper habitats, providing the fish assemblages located at the top of the summit with a deeper profile than observed in fish assemblages of the continental slope.En prensa2,48

Updating the national checklist of marine fishes in Spanish waters: An approach to priority hotspots and lessons for conservation

In response to a request from the Spanish Ministry of Farming, Fishing, Food, and Environment (Spanish: Agricultura, Pesca, Alimentación y Medio Ambiente) in 2015, a fish expert group was formed to provide a reference list of marine fish species according to five regions (marine demarcations) established by Spanish Law 41/2010 on the protection of the marine environment. The objective of this article was to update and analyse the data compiled in the marine fish species checklist in order to: 1) provide a complete list of marine fish species in the Spanish Exclusive Economic Zone; 2) compare this checklist between bio-geographical areas; and 3) identify possible priority hotspots for their conservation. We applied several indices, such as the total number of species in each area, species richness, and the Biodiversity Conservation Concern index. We discuss gaps in knowledge and the lessons learned for conservation purposes. A total of 1075 marine fishes were reported in Spanish waters. Most of these fish were well determined, whereas a few were treated as uncertain. The marine demarcation with the most species is the Canary Islands with 795 species, followed by the Spanish north coast demarcation with 506 species. However, the marine demarcations with the most species per area are the Spanish coast of the Gulf of Cádiz and the Strait of Gibraltar-Alboran Sea

List of Species as recorded by Canadian and EU Bottom Trawl Surveys in Flemish Cap

A list of species has been prepared with all records in each haul of both Canadian (1977-1985) and EU (1988-2002 and 2003-2012) bottom trawl surveys. Even though sampling intensity and taxonomic interest changed with time, the three periods can be considered almost homogeneous. Main change occurred when the EU survey increased the depth range, from 730 to 1460 meters depth, and all invertebrates were recorded