1,605 research outputs found
Living evidence of a fossil survival strategy raises hope for warming-affected corals
Climate change is affecting reef-building corals worldwide, with little hope for recovery. However, coral fossils hint at the existence of environmental stress–triggered survival strategies unreported in extant colonial corals. We document the living evidence and long-term ecological role of such a survival strategy in which isolated polyps from coral colonies affected by warming adopt a transitory resistance phase, in turn expressing a high recovery capacity in dead colony areas. Such processes have been described in fossil corals as rejuvenescence but were previously unknown in extant reef-builder corals. Our results based on 16 years of monitoring show the significance of this process for unexpected recoveries of coral colonies severely affected by warming. These findings provide a link between rejuvenescence in fossil and extant corals and reveal that beyond adaptation and acclimatization processes, modern scleractinian corals show yet undiscovered and highly effective survival strategies that help them withstand and recover from rapid environmental changes
The influence of nitrate leaching through unsaturated soil on groundwater pollution in an agricultural area of the Basque country: a case study
The average nitrate concentration in the groundwater of the Vitoria-Gasteiz (Basque Country) quaternary aquifer rose from 50 mg NO3−/l during 1986 to over 200 mg/l in 1995, which represents an increase of some 20 mg NO3−/l per year. From 1995 to 2002, the nitrate concentration of the groundwater slightly decreased. Nitrategroundwaterpollution during the period 1986–1993 was the result of the abusive use of fertilizers and of the modification in the recharge patterns of the aquifer from surface water sources. From 1993 onwards, apart from a possible rationalization in fertilizer use, the change in the origin of water for irrigation and wetland restoration (water is taken now from artificial pools outside the quaternary aquifer) must be explained in order to account for the observed decrease in nitrate concentration in the groundwater. The water of the aquifer and of the unsaturated zone were studied in two experimental plots (one of them cultivated and the other uncultivated) for 18 months (January 1993–June 1994), during the period of maximum contamination, to evaluate the effect of fertilizers on soil water and on the water in the saturated zone. The soil water was sampled using soil lysimeters at various depths. The volumetric water content of the soil was measured at the same depths using time domain reflectrometry (TDR) probes. Samples of groundwater were taken from a network of wells on the aquifer scale, two located close to the two experimental plots. The temporal evolution of nitrate concentrations in soil solutions depends on the addition of fertilizers and on soilnitrateleaching by rain. During episodes of intense rain (>50 mm in a day), the groundwater deposits are recharged with water coming from the leaching of interstitial soil solutions, causing an increase in the groundwaternitrate concentrations. The mass of nitrate leached from the cultivated zone is five times higher than that of the nitrate leached from the uncultivated zone (1147 kg NO3−/ha in the cultivated sector as against 211 kg NO3−/ha in the uncultivated sector), although part of the nitrate leached into the soil had been previously deposited by the rise of the water table. If we consider that the level of groundwater input is similar in both plots, we may conclude that 964 kg NO3−/ha circulated towards the groundwater in the cultivated zone during the period under study, representing 87% of the nitrate applied to the soil in the form of fertilizer during that period
Effects of turf algae on recruitment and juvenile survival of gorgonian corals
8 páginas, 4 figuras.During the last 2 decades, the widespread temperate gorgonian Eunicella singularis
has been among the species most affected by climate-induced mortalities. Recruitment and
juvenile survival play crucial roles in the recovery process of this species, but turf algae may affect
these early life history processes. We investigated the effects of turf algae on recruitment and
juvenile survival of E. singularis using in situ turf-removal and turf-exposure experiments. The
experiments were performed at a depth of 15 to 20 m off the island of Menorca (Balearic Islands,
NW Mediterranean Sea) between April 2008 and July 2009. The turf-removal experiment indicated
that exposure to turf algae caused up to a 5-fold reduction in the recruitment of the gorgonian
species. The turf-exposure experiment revealed that transplanted juveniles exposed to turf
algae overgrowth lost biomass and exhibited a threefold increase in juvenile mortality. These
results demonstrate the negative effects that turf algae can exert on early stages of gorgonian species;
in turn, this may affect their recovery capacity and population dynamics. Given that most
Mediterranean invasive algae form a persistent turf, an increase in turf algae abundance may
exacerbate these negative effects.Financial support was provided by
the ‘Consell Insular de Menorca’ and the ‘Ministerio de
Ciencia e Innovació (MCI)’ projects CGL2010-18466 and
CTM2009-08045. C.L. and E.C. were funded by a Juan de la
Cierva Postdoctoral Fellowship from the MCI and are part of
the Marine Conservation research group (2009SGR174);
R.C. is a member of the Marine Biogeochemistry and Global
Change research group (2009SGR142) from the Generalitat
Catalunya.Peer reviewe
DISTRIBUTION OF PIGMENT CELLS IN THE HEART OF THE RABBITFISH, CHIMAERA MONSTROSA (CONDRICHTHYES: HOLOCEPHALI)
El resumen aparece en el Program & Abstracts of the 10th International Congress of Vertebrate Morphology, Barcelona 2013. Anatomical Record, Volume 296, Special Feature — 1: P-076.The study of extracutaneous cells producing and storing melanin is of interest because it
may provide valuable information about the presence of neural crest elements in internal
organs and tissues. Here we report, for the first time, the presence and distribution of
melanophores in the heart of a chondrichthyan species, the rabbitfish, Chimaera
monstrosa. Pigment cells were found in all of 20 hearts examined. Pigment cells occur
mainly in the cardiac outflow tract, which consists of two anatomical components, the
proximal, myocardial conus arteriosus and the distal, non-myocardial bulbus arteriosus.
A few groups of dark pigmented cells were found in the apex of the ventricle of one
specimen and in the atrium of two specimens. In all instances, the melanophores were
located in the subepicardial space, where they could be well recognized in both
unstained and stained histological sections. The distribution and intensity of the
pigmentation in the cardiac outflow tract varies markedly between individuals. In all
cases, however, the pigmented area is larger on the dorsal than on the ventral surface.
Dorsally, the size of the pigmented area ranges from a fringe that includes the bulbus
and the distal part of the conus to the whole surface of the outflow tract. Ventrally, the
pigmented area does not cover the entire conus arteriosus. The intensity of the
pigmentation also varies widely; in general, it is highest at the distal portion of the conus.
There is no relationship between the distribution and intensity of the pigmentation and
the sex and age of the animals. The functional role of the pigmented cells is unknown. If
the melanophores in the heart of C. monstrosa are indeed of neural crest origin, it would
suggest a notable contribution of the neural crest cells to the cardiac outflow tract in
holocephalans.Proyecto CGL2010-16417/BOS; Fondos FEDER
BES-2011-04690
Tango y paella. Porteñas y valencianos en el comisariado de exposiciones con acento educativo
El presente trabajo introduce un nuevo planteamiento de gestión y comisariado de exposiciones, analizando dos proyectos expositivos con un marcado acento participativo, incidiendo en la vertiente social y educativa de dichas propuestas.En ambos casos los curadores han elaborado un discurso educativo que recorre elconjunto. La muestra valenciana «Caligrafías de la enfermedad» y la bonaerense «Cuando digo escuela» consideran a los visitantes como protagonistas, intérpretes y constructores de significados. Esto implica crear condiciones de apropiación de los bienes patrimoniales comunes y ofrecer experiencias de calidad para que diversos tipos de usuarios pongan en juego sus perspectivas, conocimientos, narrativas y emociones. his paper proposes a new approach to managing and curating exhibitions, analyzing two exhibition projects with a strong participatory emphasis, focusing on the social aspect of these proposals. In both cases, the curators have prepared a joint educational discourse. he Valencian «Disease"s Calligraphy» and the Buenos Aires «When I say School» consider the visitors as actors, performers and builders of meanings. he exhibitions create conditions of appropriation of heritage and ofer quality experiences for diferent users developing their perspectives, knowledge, narrative and emotions. Este artigo apresenta uma nova abordagem para a gestão e curadoria de exposições, analisando dois projetos com um forte enfoque participativo, com foco nos aspectos sociais e educacionais dessas propostas. Em os dos casos, os curadores têm desenvolvido um discurso educacional que atravessa o conjunto. A exposição «Caligraia da doença» ea mostra «Quando eu digo escola» consideran os visitantes como atores, artistas e construtores signiicados. Isto signiica criar condições de propriedade dos bens patrimoniais comuns e proporcionar experiências de qualidade para diferentes tipos de usuários a pôr em jogo a sua perspectiva, suo conhecimento, sua narrativa e suas emoções
The bulbus arteriosus of the holocephalan heart
El resumen aparece en el Program & Abstracts of the 10th International Congress of Vertebrate Morphology, Barcelona 2013.Anatomical Record, Volume 296, Special Feature — 1: P-074.Previous work has shown that the outflow tract of the elasmobranch heart, namely the
cardiac portion intercalated between the ventricle and the ventral aorta, does not consist
of a single component, the conus arteriosus, as has classically been assumed, but two,
the myocardial conus arteriosus and the non-myocardial bulbus arteriosus. From the
evolutionary perspective, knowledge of the anatomy of the cardiac outflow tract of the
holocephali is important, as they are the sister group of elasmobranchs. Our aim is to
describe the cardiac outflow tract of four holocephalan species, two of them, Chimaera
monstrosa and Hydrolagus affinis of the family Chimaeridae, and the other two, Harriotta
raleighana and Rhinochimaera atlantica, of the family Rhinochimaeridae. The cardiac
outflow tract of the four species consisted of a myocardial conus arteriosus, furnished
with valves, and a bulbus arteriosus devoid of cardiac muscle. Both the bulbus and
conus are tubular in shape. The length of the bulbus relative to the total length of the
outflow tract is somewhat smaller in the rhinochimaerids (15%-19%) than in the
chimaerids (19%-23%). The bulbus is covered by epicardium and is crossed by the main
coronary artery trunks. Histologically, the bulbus is mainly composed of elastin and
collagen, and, to a lesser extent, by smooth muscle. This suggests that in
holocephalans, the bulbus actively helps to protect the gill vasculature from exposure to
high-pressure pulses of blood. Our results prove that the bulbus arteriosus is common to
chondrichthyans. In addition, they support the hypothesis that the cardiac outflow tract
consisted of a conus arteriosus and a bulbus arteriosus from the beginning of the jawed
vertebrate radiation, contributing to our understanding of the morphological changes that
have occurred at the arterial pole of the heart in both actinopterygians and
sarcopterygians.Proyecto CGL2010-16417/BOS; Fondos FEDE
Long-term responses of the endemic reef-builder Cladocora caespitosa to Mediterranean warming
Recurrent climate-induced mass-mortalities have been recorded in the Mediterranean Sea over the past 15 years. Cladocora caespitosa, the sole zooxanthellate scleractinian reef-builder in the Mediterranean, is among the organisms affected by these episodes. Extensive bioconstructions of this endemic coral are very rare at the present time and are threatened by several stressors. In this study, we assessed the long-term response of this temperate coral to warming sea-water in the Columbretes Islands (NW Mediterranean) and described, for the first time, the relationship between recurrent mortality events and local sea surface temperature (SST) regimes in the Mediterranean Sea. A water temperature series spanning more than 20 years showed a summer warming trend of 0.06°C per year and an increased frequency of positive thermal anomalies. Mortality resulted from tissue necrosis without massive zooxanthellae loss and during the 11-year study, necrosis was recorded during nine summers separated into two mortality periods (2003-2006 and 2008-2012). The highest necrosis rates were registered during the first mortality period, after the exceptionally hot summer of 2003. Although necrosis and temperature were significantly associated, the variability in necrosis rates during summers with similar thermal anomalies pointed to other acting factors. In this sense, our results showed that these differences were more closely related to the interannual temperature context and delayed thermal stress after extreme summers, rather than to acclimatisation and adaption processes
Proposta per a un pla de zonificació dels usos en l'àmbit marí del Parc Natural del Montgrí, les Illes Medes i el Baix Ter
L’objectiu d’aquest projecte és desenvolupar un pla de zonificació del usos comercials i turístics a la costa del Montgrí compresa dins el Parc Natural del Montgrí, les Illes Medes i el Baix Ter. Aquesta proposta es farà tenint en compte la extensió i distribució dels diferents hàbitats presents a la zona i la seva distribució en base a la cartografia bionòmica desenvolupada l’any 12012 (Hereu et al., 2010; Hereu i Quintana, 2012), la
seva importància en el manteniment de la biodiversitats i la seva sensibilitat als diferents usos i possibles pertorbacions en base a les evidències científiques, així com tenint en compte els actuals usos que s’hi fan, amb l’objectiu de prioritzar la conservació fent-la compatible amb els usos que s’hi donen.
Aquesta proposta es farà de utilitzant mètodes de decisió objectius en funció de la informació disponible, mitjançant l’ús de sistemes d’informació geogràfica (SIG) i programes analítics de distribució espacial (MARXAN)
Bio-Inspired Stereo Vision Calibration for Dynamic Vision Sensors
Many advances have been made in the eld of computer vision. Several recent research trends
have focused on mimicking human vision by using a stereo vision system. In multi-camera systems, a
calibration process is usually implemented to improve the results accuracy. However, these systems generate
a large amount of data to be processed; therefore, a powerful computer is required and, in many cases,
this cannot be done in real time. Neuromorphic Engineering attempts to create bio-inspired systems that
mimic the information processing that takes place in the human brain. This information is encoded using
pulses (or spikes) and the generated systems are much simpler (in computational operations and resources),
which allows them to perform similar tasks with much lower power consumption, thus these processes
can be developed over specialized hardware with real-time processing. In this work, a bio-inspired stereovision
system is presented, where a calibration mechanism for this system is implemented and evaluated
using several tests. The result is a novel calibration technique for a neuromorphic stereo vision system,
implemented over specialized hardware (FPGA - Field-Programmable Gate Array), which allows obtaining
reduced latencies on hardware implementation for stand-alone systems, and working in real time.Ministerio de Economía y Competitividad TEC2016-77785-PMinisterio de Economía y Competitividad TIN2016-80644-
El patrimonio intangible en el Museo de las Escuelas
El patrimonio material o inmaterial está constituido por aquellas cosas, relatos o prácticas que un grupo social, institución o persona, le han otorgado cierta legitimación y significado, en un tiempo histórico determinado. Entendiendo a la escuela como una institución generadora de una cultura específica podemos acordar en que los museos sobre historia de la educación pueden conformar un corpus de patrimonio educativo intangible. En el Museo de las Escuelas hemos creado una serie de dispositivos para ello. Queremos compartir las experiencias relacionadas con la indagación en memorias individuales. En este sentido estamos construyendo lo que hemos llamado “catálogo participativo”. La conformación de un patrimonio intangible, puede contribuir a la construcción de la historia de la educación mediante el aporte de otras voces y también puede ayudar a desenterrar las memorias de los excluidos, los marginados como parte integrante de las culturas minoritarias y dominadas. Palabras clave: Museo; Patrimonio intangible; Cultura escolar; Participación
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