972 research outputs found
Biotic and Human Vulnerability to Projected Changes in Ocean Biogeochemistry over the 21st Century
Mora, Camilo ... et al.-- 14 pages, 6 figures, 1 tableOngoing greenhouse gas emissions can modify climate processes and induce shifts in ocean temperature, pH, oxygen concentration, and productivity, which in turn could alter biological and social systems. Here, we provide a synoptic global assessment of the simultaneous changes in future ocean biogeochemical variables over marine biota and their broader implications for people. We analyzed modern Earth System Models forced by greenhouse gas concentration pathways until 2100 and showed that the entire world's ocean surface will be simultaneously impacted by varying intensities of ocean warming, acidification, oxygen depletion, or shortfalls in productivity. In contrast, only a small fraction of the world's ocean surface, mostly in polar regions, will experience increased oxygenation and productivity, while almost nowhere will there be ocean cooling or pH elevation. We compiled the global distribution of 32 marine habitats and biodiversity hotspots and found that they would all experience simultaneous exposure to changes in multiple biogeochemical variables. This superposition highlights the high risk for synergistic ecosystem responses, the suite of physiological adaptations needed to cope with future climate change, and the potential for reorganization of global biodiversity patterns. If co-occurring biogeochemical changes influence the delivery of ocean goods and services, then they could also have a considerable effect on human welfare. Approximately 470 to 870 million of the poorest people in the world rely heavily on the ocean for food, jobs, and revenues and live in countries that will be most affected by simultaneous changes in ocean biogeochemistry. These results highlight the high risk of degradation of marine ecosystems and associated human hardship expected in a future following current trends in anthropogenic greenhouse gas emissions. © 2013 Mora et al.Peer Reviewe
Ecosistemas de las profundidades marinas: Reservorio privilegiado de la biodiversidad y desafíos tecnológicos
30 páginasFinancial support of the BBVA FoundationPeer reviewe
Clinical and sociodemographic predictors of oral pain and eating problems among adult and senior Spaniards in the national survey performed in 2010
Background: Pain and chewing difficulties have been identified as the strongest predictors of oral disadvantage.
The aim of this study is to analyze and quantify the sociodemographic, behavioural and clinical factors modulating
the oral pain and eating difficulties reported by Spanish adults and elderly Spanish people in the last National Oral
Health Survey performed in 2010.
Material and Methods: Data concerning pain and chewing difficulties were acquired on a Likert‑scale format
from a representative sample of the Spanish general population with ages between 35-44 years (n=391) and 65
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74
years (n=405). Risk factors were identified using bivariate analysis, after which the crude association between
risk factors (sociodemographic, behavioural and clinical) and outcome variables (pain and eating problems) was
assessed by adjusted odds ratios, calculated by means of multivariate logistic regression.
Results: Eating problems and oral pain were mainly associated with prosthetic and caries treatment needs as
clinical predictors, but female sex was also seen to be a relevant and significant risk factor for suffering pain and
eating restrictions. Paradoxically, after taking into account all the aforementioned predictors, the adults had an
almost two‑fold higher risk of reporting pain or eating difficulties than the elderly subjects.
Conclusions: In agreement with the results from the last national oral health survey, prosthetic and caries treatment needs should be considered key factors in determining the oral well
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being of the Spanish population. In
sociodemographic terms, the women and adults were seen to be at a significantly higher risk of suffering pain and
eating restrictions
Dark Matter from Lorentz Invariance and the LHC
International audienceIn extra dimensional models, a Dark Matter candidate can be present thanks to a Kaluza-Klein parity which makes the lightest resonances stable. However, compactifications considered sofar need the symmetry to be imposed by hand on the model: here we propose the unique orbifold in 6 dimensions where such parity arises naturally as part of the unbroken 6D Lorentz invariance. As an example we introduce a model of universal extra dimensions where all standard model fields propagate in the extra dimensions. The dark matter candidate is a scalar photon and its preferred mass range lies below 300 GeV. Due to the small splitting between states in the same Kaluza-Klein tier, discovery of the lightest tiers is challenging at the LH
Deep-water chemosynthetic ecosystem research during the Census of Marine Life Decade and Beyond: A Proposed Deep-Ocean Road Map
The ChEss project of the Census of Marine Life (2002–2010) helped foster internationally-coordinated studies worldwide focusing on exploration for, and characterization of new deep-sea chemosynthetic ecosystem sites. This work has advanced our understanding of the nature and factors controlling the biogeography and biodiversity of these ecosystems in four geographic locations: the Atlantic Equatorial Belt (AEB), the New Zealand region, the Arctic and Antarctic and the SE Pacific off Chile. In the AEB, major discoveries include hydrothermal seeps on the Costa Rica margin, deepest vents found on the Mid-Cayman Rise and the hottest vents found on the Southern Mid-Atlantic Ridge. It was also shown that the major fracture zones on the MAR do not create barriers for the dispersal but may act as trans-Atlantic conduits for larvae. In New Zealand, investigations of a newly found large cold-seep area suggest that this region may be a new biogeographic province. In the Arctic, the newly discovered sites on the Mohns Ridge (71°N) showed extensive mats of sulfur-oxidisng bacteria, but only one gastropod potentially bears chemosynthetic symbionts, while cold seeps on the Haakon Mossby Mud Volcano (72°N) are dominated by siboglinid worms. In the Antarctic region, the first hydrothermal vents south of the Polar Front were located and biological results indicate that they may represent a new biogeographic province. The recent exploration of the South Pacific region has provided evidence for a sediment hosted hydrothermal source near a methane-rich cold-seep area. Based on our 8 years of investigations of deep-water chemosynthetic ecosystems worldwide, we suggest highest priorities for future research: (i) continued exploration of the deep-ocean ridge-crest; (ii) increased focus on anthropogenic impacts; (iii) concerted effort to coordinate a major investigation of the deep South Pacific Ocean – the largest contiguous habitat for life within Earth's biosphere, but also the world's least investigated deep-ocean basin
Oral health behaviour and lifestyle factors among overweight young adults in Europe:a cross-sectional questionnaire study
Being overweight is a risk factor for many chronic diseases including oral diseases. Our aim was to study the associations between oral health behavior, lifestyle factors and being overweight among young European adults, 2011–2012. The subjects constituted a representative sample of adult population aged 18–35 years from eight European countries participating in the Escarcel study. The participants completed a self-administered questionnaire on dietary habits, oral health behavior, smoking, exercise, height, and weight. Overweight was defined as body mass index (BMI) ¥ 25 kg/m2 using theWorld Health Organization criteria. Mean BMI was 23.2 (SD 3.48) and 24.3% of the study population were overweight. Those who were overweight drank more soft drinks (p = 0.005) and energy drinks (p = 0.006) compared with those who were non-overweight. Brushing once a day (OR
1.6; 95% CI 1.3–2.0), emergency treatment as the reason for last dental visit (OR 1.6; 95% CI 1.3–1.9) and having seven or more eating or drinking occasions daily (OR 1.4; 95% CI 1.1–1.7) were statistically significantly associated with overweight. Associations were found between oral health behavior, lifestyle and overweight. A greater awareness of the detrimental lifestyle factors including inadequate oral health habits among overweight young adults is important for all healthcare providers, including oral health care professionals
The Universal Real Projective Plane: LHC phenomenology at one Loop
The Real Projective Plane is the lowest dimensional orbifold which, when
combined with the usual Minkowski space-time, gives rise to a unique model in
six flat dimensions possessing an exact Kaluza Klein (KK) parity as a relic
symmetry of the broken six dimensional Lorentz group. As a consequence of this
property, any model formulated on this background will include a stable Dark
Matter candidate. Loop corrections play a crucial role because they remove mass
degeneracy in the tiers of KK modes and induce new couplings which mediate
decays. We study the full one loop structure of the corrections by means of
counter-terms localised on the two singular points. As an application, the
phenomenology of the (2,0) and (0,2) tiers is discussed at the LHC. We identify
promising signatures with single and di-lepton, top antitop and 4 tops: in the
dilepton channel, present data from CMS and ATLAS may already exclude KK masses
up to 250 GeV, while by next year they may cover the whole mass range preferred
by WMAP data.Comment: 45 pages, 3 figure
Submarine canyons in the Catalan Sea (NW Mediterranean): Megafaunal biodiversity patterns and anthropogenic threats
12 pages, 13 figuresThe continental margin of the Catalonia is crossed by several submarine canyons of different evolutionary history (Fig. 1) (Canals et al., 2004a). The main characteristic of the circulation pattern on the Catalan coast is a slope current referred to as the Northern current, which is associated with a shelf–slope density front that in this area flows mainly towards the southwest (Font et al., 1988). This baroclinic current separates the low-salinity shelf waters from the denser open-sea saline watersPeer reviewe
Wave overtopping and crown wall stability of cube and Cubipod-armored mound breakwaters
[EN] The influence of the type of armor on wave overtopping on mound breakwaters is usually represented by the roughness factor. However, different values of roughness factor for the same armor unit are given in the literature. Thus, the roughness factor depends not only on the type of armor, number of layers and permeability but also on the formula and database considered. In the present thesis, a new methodology based on bootstrapping techniques is developed and applied to characterize the roughness factors for different armor units. Differences up to 20% appeared when comparing the optimum roughness factors with those given in the literature. Armor porosity greatly affects the roughness factor and the armor stability: higher armor porosities reduce wave overtopping as well as hydraulic stability. Therefore, armor porosity values usually recommended in the literature should be used to avoid damage during lifetime.
Formulas with few variables are easy to apply but they allow the roughness factor to absorb the information not explicitly included in the formula. However, the CLASH neural network avoids this problem and gives excellent estimation for wave overtopping on mound breakwaters. In this thesis, a new formula which emulates the behavior of the CLASH neural network is developed. The new formula has 16 parameters, six dimensionless input variables (Rc/Hm0, Ir, Rc/h, Gc/Hm0, Ac/Rc and a toe berm variable based on Rc/h) and two reduction factors (¿f and ¿ß). The new formula is built-up after systematic simulations using the CLASH neural network and provides the lowest prediction error.
Wave overtopping on mound breakwaters can be minimized by increasing the crest freeboard, usually with a concrete crown wall. Crown walls must resist wave loads and armor earth pressure to be stable. In the present study, small-scale test results with cube- and Cubipod-armored mound breakwaters are used to develop a new estimator for calculating horizontal and up-lift forces from waves. The new formulas include four dimensionless input variables (¿f Ru0.1%/Rc, (Rc-Ac)/Ch, ¿(L_m/G_c ) and Fc/Ch) and the crown wall geometry. The roughness factor selected for overtopping prediction is used to consider the type of armor. Up-lift forces decreased sharply with increasing foundation levels. The new formulas provide the lowest error when predicting wave forces on crown walls.[ES] La influencia del tipo de elemento del manto sobre le rebase de diques en talud se caracteriza habitualmente mediante el factor de rugosidad (¿f). Sin embargo, en la literatura existen diferentes valores del factor de rugosidad para el mismo tipo de elemento. El factor de rugosidad no depende solo del tipo de elemento, número de capas y permeabilidad del núcleo sino también de la formulación y de la base de datos empleada. En la presente tesis se desarrolla y aplica una nueva metodología basada en técnicas de bootstrapping para caracterizar estadísticamente el factor de rugosidad de diferentes elementos (entre ellos el Cubípodo) sobre diferentes formulaciones de rebase. Se observan diferencias de hasta el 20% entre los factores de rugosidad óptimos y los que se proporcionan en la literatura. La porosidad del manto afecta notablemente al factor de rugosidad pero también a la estabilidad del manto; mayores porosidades proporcionan menor rebase pero también menor estabilidad hidráulica. Por ello, las porosidades de diseño recomendadas deben emplearse para evitar daños durante la vida útil.
Fórmulas con pocas variables de entrada son sencillas de emplear pero absorben a través del factor de rugosidad toda la información que no se incluye explícitamente en las variables de entrada. En cambio, la red neuronal de CLASH evita en gran medida estos inconvenientes y al mismo tiempo proporciona excelentes para estimar el rebase sobre diques en talud convencionales. En la presente tesis se ha desarrollado una fórmula explícita que permite emular el comportamiento de la red neuronal de CLASH. La nueva fórmula posee 16 parámetros, seis variables de entrada (Rc/Hm0, ¿0,-1, Rc/h, Gc/Hm0, Ac/Rc y una variable para representar a la berma de pie basada en Rc/h) y dos factores de reducción (¿f y ¿ß). La nueva fórmula se construye en base a simulaciones controladas empleando la red neuronal de CLASH y proporciona el menor error en la predicción de rebase sobre diques en talud de entre los estimadores estudiados.
Una de las maneras más efectivas de disminuir el rebase sobre diques en talud es incrementar la cota de coronación mediante un espaldón de hormigón. Estas estructuras sufren el impacto del oleaje y deben ser diseñadas para resistirlo. En la presente tesis se han empleado ensayos de laboratorio de cubos y Cubípodos para desarrollar una nueva fórmula que permita calcular las fuerzas horizontales y verticales del oleaje sobre el espaldón. Las nuevas fórmulas incluyen la influencia de cuatro variables adimensionales (¿f Ru0.1%/Rc, (Rc-Ac)/Ch, ¿(L_m/G_c ) y Fc/Ch) y de la geometría del espaldón. Incluyen la influencia del tipo de elemento mediante el factor de rugosidad al igual que las fórmulas de rebase. Las fuerzas verticales disminuyen significativamente con el aumento de la cota de cimentación. Las nuevas fórmulas proporcionan el menor error de predicción sobre los registros de laboratorio analizados.[CA] La influència del tipus d'element del mantell principal en l'ultrapassament dics en talús és caracteritza habitualment mitjançant el factor de rugositat (¿f). En canvi, en la literatura existeixen diferents valors del factor de rugositat per al mateix tipus d'element. Així doncs, el factor de rugositat no depèn només del tipus d'element, nombre de capes i permeabilitat del nucli però també de la formulació i de la base de dades utilitzada. En la present tesi es desenvolupa i aplica una nova metodologia basada en tècniques de bootstrapping per a caracteritzar estadísticament el factor de rugositat de diferent elements (entre ells el Cubípode) utilitzant diferents formulacions d'ultrapassament. S'observen diferències fins al 20% entre els factors de rugositat òptims i els que apareixen en la literatura. La porositat del mantell afecta notablement el factor de rugositat però també a l'estabilitat del mantell; majors porositats proporcionen menor ultrapassament però també menor estabilitat hidràulica. Per això, les porositats de disseny recomanades deuen emprar-se per a evitar danys durant la vida útil.
Formules amb poques variables d'entrada són senzilles d'utilitzar però absorbeixen mitjançant el factor del factor de rugositat tota la informació que no s'inclou de manera explícita en les variables d'entrada. D'altra banda, la xarxa neuronal de CLASH evita en gran mesura aquests inconvenients i al mateix temps proporciona excel·lents resultats per a estimar l'ultrapassament sobre els dics en talús convencionals. En la present tesi s'ha desenvolupat una formulació explícita que permet emular el comportament de la xarxa neuronal de CLASH. La nova formulació té 16 paràmetres, sis variables d'entrada (Rc/Hm0, Ir, Rc/h, Gc/Hm0, Ac/Rc i una variable per a representar la berma de peu basada en Rc/h) i dos factors de reducció (¿f y ¿ß). La nova fórmula es construeix mitjançant simulacions controlades amb la xarxa neuronal de CLASH i proporciona el menor error en la predicció de l'ultrapassament sobre dics en talús de entre els estimadors analitzats.
Una de les maneres més efectives de disminuir l'ultrapassament sobre dics en talús és incrementar la cota de coronació mitjançant un espatller de formigó. Aquestes estructures sofreixen l'impacte de les ones i deuen ser dissenyades per a resistir. En la present tesi, s'utilitzen assajos de laboratori de cubs i Cubípodes per a desenvolupar una nova formulació per a calcular les forces horitzontals i verticals causades per l'onatge en l'espatller. Les noves fórmules inclouen la influència de quatre variables adimensionals (¿f Ru0.1%/Rc, (Rc-Ac)/Ch, ¿(L_m/G_c ) y Fc/Ch) i de la geometria de l'espatller. Inclouen la influència del tipus d'element mitjançant el factor de rugositat al igual que les fórmules d'ultrapassament. Les forces verticals disminueixen significativament amb l'augment de la cota de cimentació. Les noves fórmules proporcionen el menor error en la predicció sobre els registres de laboratori analitzats.Molines Llodra, J. (2016). Wave overtopping and crown wall stability of cube and Cubipod-armored mound breakwaters [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/62178TESI
Spatio-temporal monitoring of deep-sea communities using metabarcoding of sediment DNA and RNA
We assessed spatio-temporal patterns of diversity in deep-sea sediment communities using metabarcoding. We chose a recently developed eukaryotic marker based on the v7 region of the 18S rRNA gene. Our study was performed in a submarine canyon and its adjacent slope in the Northwestern Mediterranean Sea, sampled along a depth gradient at two different seasons. We found a total of 5,569 molecular operational taxonomic units (MOTUs), dominated by Metazoa, Alveolata and Rhizaria. Among metazoans, Nematoda, Arthropoda and Annelida were the most diverse. We found a marked heterogeneity at all scales, with important differences between layers of sediment and significant changes in community composition with zone (canyon vs slope), depth, and season. We compared the information obtained from metabarcoding DNA and RNA and found more total MOTUs and more MOTUs per sample with DNA (ca. 20% and 40% increase, respectively). Both datasets showed overall similar spatial trends, but most groups had higher MOTU richness with the DNA template, while others, such as nematodes, were more diverse in the RNA dataset. We provide metabarcoding protocols and guidelines for biomonitoring of these key communities in order to generate information applicable to management efforts
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