Evaluating wind datasets for wave hindcasting in the NW Iberian Peninsula coast

The available wind datasets can be exploited to support the setup of accurate wave models, able to reproduce and forecast extreme event scenarios. It is of utmost importance in the actual context of climate change. This study focuses on evaluating the performance of a numerical wave model, using different wind datasets, helping to create a tool to assess coastal risks, and further on to support the future implementation of reliable warning systems based on numerical models. The numerical model SWAN was implemented, configured and validated for the NW Iberian Peninsula coast, as a test case region. A period of two months, from December 2013 to January 2014, was simulated due to the winter storms that crossed the area. Six distinct wind datasets were selected to test their suitability in regional wave modelling. The results were validated against several sets of wave buoy data, considering wave parameters such as significant wave height, mean wave period and peak direction. The implemented wave model configuration allowed the representation of the wave evolution with relatively good accuracy. All the wind datasets were able to produce reasonably good wave condition estimates. The dataset that best represented the wave properties varied from one wave parameter to another, but the most reliable for the selected region was the reanalysis product generated at the European Centre for Medium-Range Weather Forecasts

A tale of two "canyon" systems; Gollum & Whittard

Within the framework of the EC FP6 HERMES project, Ghent University organised a joint geophysical and biological research cruise to the Gollum and Whittard Canyon system with R/V Belgica from 23rd to 29th of June 2006. The aim was to study the local ecosystems and their drivers. In combining and integrating various scientific disciplines, it is aimed to get a complete picture on how biodiversity, biological processes and physical factors are linked to each other and how they can control the various ecosystems along the European Margin.During this campaign, special attention was given to the upper slope configuration of the Gollum channel heads, fitting in a framework of multibeam bathymetry ........(Beyer et al., 2003), seismic profiling and TOBI side-scan sonar data ....................(Wheeler et al., 2003) collected during previous campaigns. The main Gollum channel system is characterised by several deeply incised canyons with numerous slide scars on their flanks. Their pathways seem to be influenced by a structural control, creating a bayonet-shaped course. Upstream of this structural feature, the channel floor deposits are characterized by thick acoustically transparent units suggesting ponded turbidites or mass-wasting deposits. A long piston core, acquired with R/V Marion Dufresne in 2001 (MD01-2464), however, only yields a small number of fine-grained turbidites in a muddy hemipelagic host sediment. This suggests that this system has known a relatively low activity during Quaternary times. The high-resolution single-channel sparker geophysical survey on the Whittard canyon system was originally designed to better document its morphology and structure and to assist finding suitable places for biological sampling. During this survey, a set of enigmatic mound-like structures were found in water depths of 300 to 500m, very much alike the coral banks observed in the Porcupine basin, recently drilled by IODP expedition 307 ......................(IODP 307 Expedition Scientists, 2005; De Mol et al., 2002). They are closely associated to a downslope gully of the Whittard canyon and some levee (or even drift) deposits. The presence of coral banks in this canyon location would be a perfect example of the HERMES ecosystem hotspots. However, only few profiles were acquired and no detailed bathymetric data was available at the time of the campaign. Further investigations within the HERMES community will be conducted in order to verify this potentially interesting observation

Interêt de la Refraction Sous Cycloplegie chez l’Adulte Jeybe a Citonou

Les vices de réfraction ou amétropies sont représentés par toutes les situations où le système optique de l’œil ne permet pas de focaliser l’image d’un objet sur la rétine. Cette recherche se voulait d’étudier les variations de la réfraction sous cycloplégie chez l’adulte jeune. Elle était rétrospective sur 05 ans à l’ex Hôpital d’Instruction des Armées – Centre Hospitalier Universitaire de Cotonou considérant 2224 yeux de patients âgés de 18 à 38 ans respectant les critères d’inclusion. La régression linéaire a été utilisée en vue d’étudier la relation entre la puissance des sphères, du cylindre et l’équivalent sphérique avant et après la cycloplégie. L’âge moyen des patients était de 27,2 ans ± 6,1. Les céphalées représentaient 56,1% des motifs de consultation et la douleur oculaire 51,8%. Avant la cycloplégie, on comptait 57,7% de myopes et 29,8% d’hypermétropes ; après la cycloplégie, 20,5 % de myopes et 74,1% d’hypermétropes. À partir des équivalents sphériques, la variation moyenne de la puissance des sphères était statistiquement significative (p < 0,0001). Elle était de 0,14 D chez les myopes, de 0,26 D chez les hypermétropes. La cycloplégie a une influence significative sur l’équivalent sphérique dans toutes les tranches d’âge jusqu’à 38 ans (p < 0,0001). L’estimation de la réfraction sans cycloplégie n’est donc pas précise. En effet, la cycloplégie en relâchant l’accommodation permet d’estimer de façon pertinente la valeur exacte et précise de la réfraction.   Refractive errors or ametropias encompass situations where the optical system of the eye fails to focus the image of an object onto the retina. This study aimed to investigate variations in refraction under cycloplegia in young adults. It was a retrospective study conducted over a period of 5 years at the former Military Teaching Hospital - University Hospital Center of Cotonou, involving 2224 eyes of patients aged 18 to 38 years who met the inclusion criteria. Linear regression was employed to examine the relationship between the power of spheres, cylinders, and spherical equivalent before and after cycloplegia. The average age of patients was 27.2 years ± 6.1. Headaches accounted for 56.1% of the reasons for consultation, and ocular pain for 51.8%. Before cycloplegia, 57.7% were myopic, and 29.8% were hyperopic; after cycloplegia, 20.5% were myopic, and 74.1% were hyperopic. Based on spherical equivalents, the average change in sphere power was statistically significant (p < 0.0001). It was 0.14 D for myopes and 0.26 D for hypermetropes. Cycloplegia had a significant influence on the spherical equivalent across all age groups up to 38 years (p < 0.0001). Therefore, estimating refraction without cycloplegia is not accurate. Indeed, cycloplegia, by relaxing accommodation, allows for a relevant estimation of the exact and precise value of refraction

Impacts of Ocean Acidification on Sediment Processes in Shallow Waters of the Arctic Ocean

International audienceDespite the important roles of shallow-water sediments in global biogeochemical cycling, the effects of ocean acidification on sedimentary processes have received relatively little attention. As high-latitude cold waters can absorb more CO 2 and usually have a lower buffering capacity than warmer waters, acidification rates in these areas are faster than those in subtropical regions. The present study investigates the effects of ocean acidification on sediment composition, processes and sediment-water fluxes in an Arctic coastal system. Undisturbed sediment cores, exempt of large dwelling organisms, were collected, incubated for a period of 14 days, and subject to a gradient of pCO 2 covering the range of values projected for the end of the century. On five occasions during the experimental period, the sediment cores were isolated for flux measurements (oxygen, alkalinity, dissolved inorganic carbon, ammonium, nitrate, nitrite, phosphate and silicate). At the end of the experimental period, denitrification rates were measured and sediment samples were taken at several depth intervals for solid-phase analyses. Most of the parameters and processes (i.e. mineralization, denitrification) investigated showed no relationship with the overlying seawater pH, suggesting that ocean acidification will have limited impacts on the microbial activity and associated sediment-water fluxes on Arctic shelves, in the absence of active bio-irrigating organisms. Only following a pH decrease of 1 pH unit, not foreseen in the coming 300 years, significant enhancements of calcium carbonate dissolution and anammox rates were observed. Longer-term experiments on different sediment types are still required to confirm the limited impact of ocean acidification on shallow Arctic sediment processes as observed in this study

Interêt de la Refraction Sous Cycloplegie chez l’Adulte Jeybe a Citonou

Les vices de réfraction ou amétropies sont représentés par toutes les situations où le système optique de l’œil ne permet pas de focaliser l’image d’un objet sur la rétine. Cette recherche se voulait d’étudier les variations de la réfraction sous cycloplégie chez l’adulte jeune. Elle était rétrospective sur 05 ans à l’ex Hôpital d’Instruction des Armées – Centre Hospitalier Universitaire de Cotonou considérant 2224 yeux de patients âgés de 18 à 38 ans respectant les critères d’inclusion. La régression linéaire a été utilisée en vue d’étudier la relation entre la puissance des sphères, du cylindre et l’équivalent sphérique avant et après la cycloplégie. L’âge moyen des patients était de 27,2 ans ± 6,1. Les céphalées représentaient 56,1% des motifs de consultation et la douleur oculaire 51,8%. Avant la cycloplégie, on comptait 57,7% de myopes et 29,8% d’hypermétropes ; après la cycloplégie, 20,5 % de myopes et 74,1% d’hypermétropes. À partir des équivalents sphériques, la variation moyenne de la puissance des sphères était statistiquement significative (p < 0,0001). Elle était de 0,14 D chez les myopes, de 0,26 D chez les hypermétropes. La cycloplégie a une influence significative sur l’équivalent sphérique dans toutes les tranches d’âge jusqu’à 38 ans (p < 0,0001). L’estimation de la réfraction sans cycloplégie n’est donc pas précise. En effet, la cycloplégie en relâchant l’accommodation permet d’estimer de façon pertinente la valeur exacte et précise de la réfraction.   Refractive errors or ametropias encompass situations where the optical system of the eye fails to focus the image of an object onto the retina. This study aimed to investigate variations in refraction under cycloplegia in young adults. It was a retrospective study conducted over a period of 5 years at the former Military Teaching Hospital - University Hospital Center of Cotonou, involving 2224 eyes of patients aged 18 to 38 years who met the inclusion criteria. Linear regression was employed to examine the relationship between the power of spheres, cylinders, and spherical equivalent before and after cycloplegia. The average age of patients was 27.2 years ± 6.1. Headaches accounted for 56.1% of the reasons for consultation, and ocular pain for 51.8%. Before cycloplegia, 57.7% were myopic, and 29.8% were hyperopic; after cycloplegia, 20.5% were myopic, and 74.1% were hyperopic. Based on spherical equivalents, the average change in sphere power was statistically significant (p < 0.0001). It was 0.14 D for myopes and 0.26 D for hypermetropes. Cycloplegia had a significant influence on the spherical equivalent across all age groups up to 38 years (p < 0.0001). Therefore, estimating refraction without cycloplegia is not accurate. Indeed, cycloplegia, by relaxing accommodation, allows for a relevant estimation of the exact and precise value of refraction

Ossifying fibroma of the maxillary sinus at the Kara (Togo) Teaching Hospital

SummaryIntroductionOssifying fibroma of the jaw is a benign tumorous disease, somewhat rare and aggressive. It frequently targets the mandible, but seldom the maxillary.Case studyThe present study reports the first case of left maxillary sinus fibroma treated at the Kara Teaching Hospital in North Togo. It occurred in a 29-year-old patient who experienced slow-growing tumefaction of the left maxillary sinus, resulting in deformation of the left side of the face in the maxillary region and ipsilateral nasal obstruction. Orthopantomography showed a displacement of teeth 21, 22, and 23 with an abnormal degree of opacity at the dental roots. The CT scan of the nose and sinuses revealed a tumorous lesion of expanding bony density increasing in volume at the outer wall of the left maxillary sinus, of regular shape that contained microscopic calcifications, extending into the ipsilateral orbital floor and pushing the surrounding soft tissues forward without invading them. The histopathological examination of the tumor confirmed the diagnosis of ossifying fibroma.DiscussionOssifying fibroma or fibrous osteoma is a rare and benign lesion developing insidiously with a polymorphous aspect. Of unknown etiology, most frequently located in the mandible, it is differentiated from other types of fibroma in its clinical, radiological, and histological aspects. However, only examination of the gross specimen can provide the final diagnosis. Treatment requires surgery.ConclusionSurgical treatment entailed the complete macroscopic enucleoresection. Recovery has been favorable at 2 years of follow-up

Linking short- to medium-term beach dune dynamics to local features under wave and wind actions: a northern portuguese case study

Many coasts suffer from prevailing erosion, with them being particularly vulnerable to predicted climate change impacts, threatening coastal ecosystems, their services, infrastructures and populations. Understanding coastal morpho-sedimentary dynamics is thus essential for coastal management. However, coastal vulnerability may differ locally, depending on exposure/protection and local geological and morpho-hydrodynamical features, suggesting that a local approach to erosion risk assessment is needed to identify and understand local patterns. Digital elevation models of a 14 km long coastal stretch in northern Portugal that were extracted from aerial surveys obtained between November 2008 and February 2019 were analysed to quantify changes in shoreline position and sediment budgets, both for the whole study area and for distinct beach segments. The observed dynamics were subsequently analysed by considering prevailing wave and wind intensities and directions. Overall and during the decade analysed, the beach–dune system of the studied stretch slightly increased in volume (0.6%), although the shoreline retreated (by 1.6 m on average). Temporal variability in coastal dynamics was observed at all of the temporal scales considered—from seasons to 5-year periods—with them being related to variability in ocean and wind patterns. There was a trend from accretional to erosional conditions, with the first 5-year period showing a mean increase in the beach–dune system’s volume of 0.6% and a mean shoreline progradation of 1.5 m, followed by 5-years with 0.0% volume change and 3.1 m shoreline retreat. Locally, the dynamics were very variable, with shoreline dynamics ranging from 24.0 m regression to 51.5 m progradation, and sediment budgets from 213.8 m3 loss to 417.0 m3 gain, per segment and for the decade. Stretches with relatively stable morphologies and others with erosional or accretional trends were found, depending on the beach type, shoreline orientation and the presence of defence structures. Rocky beaches were the least dynamic and sandy beaches the most dynamic, with mean shoreline position changes of 0.0 m and −3.4 m, respectively, and mean sediment budgets of −1.1 m3 and −2.9 m3 per linear meter of coastline, respectively, for the studied decade. The observed dynamics showed how local conditions interacted with meteo-ocean conditions in shaping local morpho-sedimentary dynamics, stressing the importance of a local approach to coastal erosion monitoring and risk assessment.European Union MarRISK project: Adaptación costera ante el Cambio Climático: conocer los riesgos y aumentar la resiliencia (0262_MarRISK_1_E) through EP INTERREG V A España-Portugal (POCTEP) program and the project INNOVMAR-Innovation and Sustainability in the Management and Exploitation of Marine Resources (NORTE-01-0145-FEDER-000035, within Research Line ECOSERVICES), supported by NORTE 2020, under the PORTUGAL 2020 Partnership Agreement, through the ERD

Integração de metodologias no estabelecimento de um programa de monitorização costeira para avaliação de risco

Na zona costeira do noroeste de Portugal os processos erosivos em curso têm vindo progressivamente a constituir motivo de preocupação, quer para os responsáveis pela gestão da zona costeira, quer para a população em geral. As principais causas apontadas para a origem destes processos são: (i) diminuição dos caudais sedimentares fluviais, devido à construção de barragens, dragagens, extracção de inertes e esgotamento dos depósitos sedimentares da plataforma interna, (ii) influência de estruturas de protecção costeira, (iii) aumento do nível do mar e da frequência e intensidade das tempestades. Tomando como caso de estudo a zona costeira de Vila Nova de Gaia, exemplo paradigmático de grande ocupação do litoral, implementou-se em 2008 um novo programa extensivo de monitorização, integrando diferentes tecnologias, de forma a avaliar as tendências evolutivas da morfodinâmica do sistema costeiro, incluindo a faixa litoral submersa, a praia e as dunas. O programa de monitorização integra observações de campo, amostragem de sedimentos e de perfis de praia, fotografia aérea, levantamentos batimétricos, e levantamentos com um sistema de mapeamento móvel com GPS e câmaras de vídeo. Desde 2008 têm sido efectuadas duas campanhas anuais utilizando esta metodologia de monitorização que permitiu avaliar as tendências evolutivas da morfodinâmica costeira e obter a informação de base para estabelecer mapas de risco de erosão para a zona de estudo. Observam-se três tendências ao longo da zona estudada: segmentos com erosão, segmentos com acreção e segmentos estáveis. Para além dos processos naturais decorrentes da morfologia da costa e das condições meteorológicas, as causas de origem antropogénica surgem como um dos principais factores desequilibradores na dinâmica costeira. Exemplos disso são a obra do emissário da praia de Canide e do quebra-mar do portinho da Aguda. Nestes locais observa-se uma forte erosão nos segmentos a sul das estruturas, enquanto a barlamar dá-se tendencialmente uma deposição de sedimentos. Concluiu-se que a maioria dos segmentos está sujeita a processos de erosão, com algumas zonas de acreção, em parte resultantes de recarga artificial das praias. Estas conclusões constituem motivo de preocupação pelo facto de a mobilidade natural dos sistemas costeiros se encontrar reduzida devido à artificialização da costa, numa zona de elevada ocupação populacional