888 research outputs found
Open ocean temperature and salinity trends in the Canary Current Large Marine Ecosystem
The Sea Surface Temperature in the Canary Current Large Marine Ecosystem (CCLME) for the 32 years in
the period 1982‐2013 shows a mean warming trend of 0.28°C decade‐1. However, this overall warming
trend shows significant changes due to the influence of the different dynamical regimes that coexist in the
CCLME. Near the coast, in the area under the influence of the upwelling, between Cape Blanc and Cape
Beddouza, the warming trend is not statistically different from zero. Near the coast, but in the waters
under the influence of downwelling, between Cape Verde and Cape Blanc, the warming trend is higher
(>0.5°C decade‐1), and statistically significant. In the oceanic regions, there is a statistically significant trend
of 0.25°C decade‐1, a trend that is also observed in waters shallower than the permanent thermocline (200‐
600 dbar). This warming rate is density compensate, with an increase in salinity of 0.02 decade‐1. Neither
the intermediate waters nor the upper deep waters show any statistically significant trend. The deep
waters (2600‐3600 dbar) in the oceanic waters north of the Canary Islands, show a warming rate of
‐0.01°C decade‐1 and a freshening of ‐0.002 decade‐1.En prens
The Canary Basin contribution to the seasonal cycle of the Atlantic Meridional Overturning Circulation at 26°N
This study examines the seasonal cycle of the Atlantic Meridional Overturning Circulation (AMOC) and its eastern boundary contributions. The cycle has a magnitude of 6 Sv, as measured by the RAPID/MOCHA/WBTS project array at 26°N, which is driven largely by the eastern boundary. The eastern boundary variations are explored in the context of the regional circulation around the Canary Islands. There is a 3 month lag between maximum wind forcing and the largest eastern boundary transports, which is explained in terms of a model for Rossby wave generated at the eastern boundary. Two dynamic processes take place through the Lanzarote Passage (LP) in fall: the recirculation of the Canary Current and the northward flow of the Intermediate Poleward Undercurrent. In contrast, during the remaining seasons the transport through the LP is southward due to the Canary Upwelling Current. These processes are linked to the seasonal cycle of the AMOC
Recent Trends in SST, Chl-a, Productivity and Wind Stress in Upwelling and Open Ocean Areas in the Upper Eastern North Atlantic Subtropical Gyre
The global upper ocean has been warming during the last decades accompanied with a chlorophyll-a (Chl-a) and productivity decrease. Whereas subtropical gyres show similar trends, Eastern Boundary Upwelling Systems are thought to increase in productivity due to increased trade winds. This study analyzes recent trends in sea surface temperature (SST), Chl-a, net primary production (NPP) and meridional wind stress in the Eastern North Atlantic subtropical gyre (NASE) in order to examine if the global trends can be detected in open ocean and upwelling areas and how the ocean biota responds. Satellite data of such variables of the last 15–40 years were analyzed to calculate mean trends in upwelling areas in the Canary upwelling system and open ocean areas around the Azores, Madeira and the Canary Islands. Our results show significant warming in the area with a maximum of 2.7°C per century for the Azores. Moreover, a general decreasing trend for Chl-a and NPP seems to be more evident in the permanent upwelling areas, which will be responsible for a loss of 0.13% of the global NPP per century. Our results also highlight a significant expansion of the oceanic desert area of 10% with an increase in unproductive days of up to 84 days in the last 20 years. The competitive relationship of stratification and wind stress in the Canary upwelling system might be a more plausible explanation for the decrease in Chl-a and NPP in upwelling areas linked to the increase in upwelling favorable wind stress and the surface warming.En prens
Comportamiento del síndrome demencial y la enfermedad de Alzheimer
Las demencias y la enfermedad de Alzheimer constituyen un serio y creciente problema de salud en países con una alta expectativa de vida como el nuestro. Con el objetivo de identificar el comportamiento del síndrome demencial y la enfermedad de Alzheimer en pacientes de 65 años y más en el Policlínico 27 de Noviembre del municipio Marianao, se presenta un estudio descriptivo de corte transversal. El diagnóstico de los pacientes se basó en los criterios internacionalmente establecidos del DSM- IV y del NINCDS- ARDRA. Se estudiaron 300 adultos mayores y se obtuvieron los porcentajes del síndrome demencial global y por tipo de demencia. El 12 % de los adultos mayores presentaron un síndrome demencial, correspondiendo a la demencia tipo Alzheimer 63.89% del total de casos y a la demencia vascular 22.22%. Encontramos un incremento de la presencia del síndrome demencial con la edad, en el sexo femenino, y en pacientes con primaria inconclusa. Las enfermedades asociadas más importantes resultaron la hipertensión arterial, la cardiopatía isquémica y la enfermedad cerebro vascular. Se recomienda la realización de proyectos de intervención, dirigidos a la población en riesgo y su familia. <br /
Differences between 1999 and 2010 across the Falkland Plateau: fronts and water masses
Decadal differences in the Falkland Plateau are
studied from the two full-depth hydrographic data collected
during the ALBATROSS (April 1999) and MOC-Austral
(February 2010) cruises. Differences in the upper 100 dbar
are due to changes in the seasonal thermocline, as the ALBATROSS
cruise took place in the austral fall and the MOCAustral
cruise in summer. The intermediate water masses
seem to be very sensitive to the wind conditions existing in
their formation area, showing cooling and freshening for the
decade as a consequence of a higher Antarctic Intermediate
Water (AAIW) contribution and of a decrease in the Subantarctic
Mode Water (SAMW) stratum. The deeper layers
do not exhibit any significant change in the water mass properties.
The Subantarctic Front (SAF) in 1999 is observed at
52.2–54.8 W with a relative mass transport of 32.6 Sv. In
contrast, the SAF gets wider in 2010, stretching from 51.1
to 57.2 W (the Falkland Islands), and weakening to 17.9 Sv.
Changes in the SAF can be linked with the westerly winds
and mainly affect the northward flow of Subantarctic Surface
Water (SASW), SAMW and AAIW/Antarctic Surface Water
(AASW). The Polar Front (PF) carries 24.9 Sv in 1999
(49.8–44.4 W), while in 2010 (49.9–49.2 W) it narrows
and strengthens to 37.3 Sv.En prens
Assessing a novel modelling approach with high resolution UAV imagery for monitoring health status in priority riparian forests
ResearchBackground: Black alder (Alnus glutinosa) forests are in severe decline across their area of distribution due to a
disease caused by the soil-borne pathogenic Phytophthora alni species complex (class Oomycetes), “alder
Phytopththora”. Mapping of the different types of damages caused by the disease is challenging in high density
ecosystems in which spectral variability is high due to canopy heterogeneity. Data obtained by unmanned aerial
vehicles (UAVs) may be particularly useful for such tasks due to the high resolution, flexibility of acquisition and cost
efficiency of this type of data. In this study, A. glutinosa decline was assessed by considering four categories of tree
health status in the field: asymptomatic, dead and defoliation above and below a 50% threshold. A combination of
multispectral Parrot Sequoia and UAV unmanned aerial vehicles -red green blue (RGB) data were analysed using
classical random forest (RF) and a simple and robust three-step logistic modelling approaches to identify the most
important forest health indicators while adhering to the principle of parsimony. A total of 34 remote sensing
variables were considered, including a set of vegetation indices, texture features from the normalized difference
vegetation index (NDVI) and a digital surface model (DSM), topographic and digital aerial photogrammetry-derived
structural data from the DSM at crown level.
Results: The four categories identified by the RF yielded an overall accuracy of 67%, while aggregation of the
legend to three classes (asymptomatic, defoliated, dead) and to two classes (alive, dead) improved the overall
accuracy to 72% and 91% respectively. On the other hand, the confusion matrix, computed from the three logistic
models by using the leave-out cross-validation method yielded overall accuracies of 75%, 80% and 94% for four-,
three- and two-level classifications, respectively.
Discussion: The study findings provide forest managers with an alternative robust classification method for the
rapid, effective assessment of areas affected and non-affected by the disease, thus enabling them to identify
hotspots for conservation and plan control and restoration measures aimed at preserving black alder forestsinfo:eu-repo/semantics/publishedVersio
Total carbon column observing network (TCCON) activities at Izaña, Tenerife (28º N, 17º W) [Póster]
Póster presentado en: 37th Annual European Meeting on Atmospheric Studies by Optical Methods celebrado del 23 al 26 de agosto de 2010 en Valladolid
Contribución a la epigrafía del Oeste de la provincia de Salamanca : el conjunto de Medina del Campo (Valladolid)
A finales del verano de 1991 estudiamos una colección particular de 28 epígrafes romanos depositados en una casa de campo próxima a la localidad de Medina del Campo'. Los epígrafes proceden de una gran necrópolis romana situada en un cerro llamado Cabeza de San Pedro, en el término municipal de Hinojosa de Duero (Salamanca) junto al salto de Saucelle, durante cuya construcción —fue inaugurado en 1956— pasaron estas lápidas a manos de particulares. El objetivo de este trabajo es, pues, hacer algunas referencias y puntualizaciones sobre todo el conjunto de epígrafes de Hinojosa de Duero, relacionándolo con la epigrafía de algunas localidades, como Astorga o Chaves, y de algunas regiones, como la comprendida entre los ríos Duero y Sabor, la zona zamorana y el occidente salmantino
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