185 research outputs found
Shipboard measurements of sediment stability using a small annular flume—Core Mini Flume (CMF)
No full textEstimates of bed stability in coastal environments are essential to physical, biological, and chemical investigations of cohesive sediments. The Core Mini Flume (CMF), a 200 mm diameter annular flume has been designed to undertake sediment stability experiments on collected intact sediment box cores. Bed properties were assessed for replicate box cores at 3 contrasting sites in UK coastal waters (Tyne [in 2011 and 2012], Plymouth and Celtic Deep), each covering a maximum area of 80 m2. No significant horizontal spatial variations were found for grain size, bulk density, porosity, or oxygen penetration at the sites. Resuspension experiments performed on replicate cores yielded highly replicable results for each site, giving average erosion thresholds of 0.33 ± 0.02 (Tyne 2011), 0.215 ± 0.03 (Tyne 2012), 0.23 ± 0.01 (Plymouth), and 0.09 ± 0.006 (Celtic Deep) Pa and erosion depths of 10.7 ± 1.7, 6.63 ± 1.10, 3.65 ± 0.95, and 4.6 ± 0.5 mm. Using an already established methodology, the CMF allowed detailed replicate experiments to be performed on-board ship rapidly after sediment collection, while minimizing the time spent at each station. The use of intact box cores minimized the disturbance to the bed often associated with recovering material to a laboratory or remoulding a bed. We have demonstrated that the convenience of laboratory-based methodologies can be combined with the benefit of prompt investigations on undisturbed beds complete with overlying in situ water to produce robust measurements of sediment stability
PERUBAHAN pH SALIVAANTARA SEBELUM DAN SESUDAH MENYIKAT GIGI DENGAN MENGGUNAKAN TEKNIK FONES
No full textPlaque, debris and bacteria that process on the surface of the tooth at a certain time will turn into lactic acid that decreases the pH of the mouth. This condition will cause caries. So the plaque should be cleaned by brushing your teeth properly. There are several techniques to brush teeth, one of them is fones technique. This study aims to describe the changes in the pH of saliva before and after brushing teeth by using fones technique.This type of research is quasi experimental with pretest and posttest design.The sampling technique uses purposive sampling with the number of samples are 49 respondents. Instrument in this research is observation sheet and pH meter. The data analysisis presented in the form of frequency distribution table. The results showed that almost half of the respondents (47%) had an acid saliva pH before performing tooth-brushing action with the fones technique. After doing the tooth brushing technique, it was found that most respondents (63%) had neutral saliva pH.The conclusion is that there is a good change between before and after brushing with the technique of fones, which is from base to neutral by 12% of respondents and from acid to neutral by 33% of respondents. The author advised the respondents to apply the fones techniques when brushing their teeth, then for UKGS schools to apply the fones technique when implementing a joint toothbrush program
Contribuição ao estudo da técnica de escovação dentária de fones /
No full textDissertação (Mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências da Saúde
High-resolution metal gradients measured by in situ DGT/DET deployment in Black sea sediments using an autonomous benthic lander
No full textDET (Diffusive equilibration in thin films) and DGT (diffusive gradients in thin films) have been deployed in situ using an autonomous benthic lander to measure concentrations and induced fluxes of Fe and Mn (DET/DGT) and trace metals (DGT) in pore waters at millimeter spatial resolutions. The newly developed deployment system is described, and based on these first results, its strengths and weaknesses are discussed. Deployments were made in the Western Black Sea in shelf sediments overlain by well‐oxygenated water at a water depth of 77 m. Maxima of the redox‐sensitive metals at 4 and 8 cm deep within the sediment indicated that two zones of reduction dominated the geochemistry. Sharp, but systematic, features were superimposed on this general picture and were well replicated in the profiles of Mn, Co, and Cd, but the sharp features in the Fe profile were offset from those of the others elements by several millimeters. Detection of this functional discrimination between Fe and Mn as regulators of trace metals would not have been possible using more conventional sampling procedures
Simultaneous determination of in situ vertical transitions of color, pore-water metals, and visualization of infaunal activity in marine sediments
No full textThe vertical color transition from brown to gray-green in marine sediments is linked to the Fe redox boundary and is commonly used as a proxy for biogeochemical state. We combine time-lapse sediment profile imaging with diffusive gradient thin (DGT) gels to obtain simultaneous in situ measurements of sediment color profiles, pore-water Fe and Mn profiles, and qualitative estimates of faunal activity at the Oyster Ground and North Dogger (North Sea). Analysis of Fe and Mn profiles using generalized additive modeling reveals that high variability between profiles within the sites makes it difficult to determine any intersite differences in trace metal behavior. At the Oyster Ground, the depth of sediment color transition (4.78 +/- 0.76 cm) was not significantly different from the Fe redox boundary (7.67 +/- 4.04 cm). At the North Dogger, there was a significant discrepancy between the depth of the sediment color transition (2.86 +/- 0.78 cm) and the Fe redox boundary (10.17 +/- 1.04 cm), which most likely results from high sulfate reduction rates at the North Dogger, leading to complexation of reduced iron to a form not available to the DGT technique. The differences in the coupling of sediment color and the Fe redox boundary between stations is likely to be related to variations in recent infaunal bioturbation activity, rather than variations in sediment source or fundamental differences in bulk sediment chemistry. Our results highlight the importance of the infaunal community in mediating Fe and Mn cycles, which are key pathways in the degradation of organic matter, and suggest that descriptions of bulk chemistry alone may be insufficient to understand the dynamics of biogeochemical cycling
Perfil de resistência de microrganismos isolados em fones de ouvidos de alunos de uma instituição de ensino superior de Juazeiro do Norte-CE
No full textO objetivo do presente estudo foi avaliar o perfil de resistência de microrganismos isolados em fones de ouvidos de alunos de uma instituição de ensino superior (IES) de Juazeiro do Norte-CE. Foram adquiridas 40 amostras aleatoriamente com os discentes da IES e acondicionadas em tubos contendo solução salina, essas amostras foram levadas para o laboratório de microbiologia do Centro Universitário Dr. Leão Sampaio, onde foram abertos e inoculados em meio Brain Hair Infusion (BHI), onde foram incubados em estufa bacteriológica a 37 ºC. Após 24 horas foi realizado o semeio nos meios de cultura (Agar Manitol Salgado, Agar Sangue e Agar Eosina Azul de Metileno - EMB), posteriormente foram realizadas as provas bioquímicas para confirmação das espécies, por fim realizou-se o antibiograma utilizando os discos de Amicacina, Gentamicina, Ofloxacina, Oxacilina, Norfloxacina, Ciprofloxacina e Penicilina G. Foi observado que 100 % das amostras encontravam-se contaminadas por um ou mais tipos de microrganismos (12,5 % de Streptococcus sp, 70 % de Staphylococcus aureus, Staphylococcus coagulase negativa 30%, Citrobacter freundii 7,5 %, Enterobacter aerogenes 2,5 % e Cândida sp. 35 %). A partir do antibiograma foi possível observar resistência das cepas para os antibióticos Penicilina G e Oxacilina. Baseado nos resultados obtidos é necessário que os discentes tenham um cuidado maior com os fones de ouvidos uma vez que, eles mal higienizados podem aglomerar diversos tipos de bactérias resistentes e podem causar infecções no canal auditivo
Caracterização de fontes sonoras e aplicação na auralização de ambientes
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológio. Programa de Pós-Graduação em Engenharia Mecânica.O objetivo da auralização é proporcionar ao ouvinte uma impressão de como uma fonte soa dentro de um ambiente, mesmo que esse ambiente não exista fisicamente. Existem hoje disponíveis alguns métodos pelos quais é possível modelar o campo acústico associado a uma posição em relação a uma fonte sonora dentro de uma sala. Neste trabalho, os métodos geométricos de modelagem conhecidos como Fontes Virtuais, Traçado de Raios e Traçado de Pirâmides foram utilizados separadamente e seus resultados audíveis foram comparados a um som de referência. Esta referência consiste em uma gravação biaural da fonte feita dentro de uma sala existente, em igual posição considerada na simulação. As fontes sonoras estudadas foram: um aparelho de ar-condicionado, um violão e a voz humana. A sala considerada foi uma sala de reuniões. Os métodos de Fontes Virtuais e Traçado de Raios foram aplicados nas simulações através de um programa em desenvolvimento chamado MÓDULOS, enquanto o programa comercial de simulação RAYNOISE foi utilizado para aplicar o método de Traçado de Pirâmides. A comparação dos resultados foi realizada por meio de duas diferentes abordagens: comparação subjetiva e análise espectral. Os resultados permitiram avaliar as vantagens e desvantagens de cada método, bem como identificar as possíveis fontes de incertezas dentro da cadeia de análise que envolve gravação, modelagem computacional, processamento digital de sinais e reprodução via fones de ouvido
Dr. Civilion Fones.
No full textEditors: Aug. 1859-July 1865, J. D. White, J. H. McQuillen, G. J. Ziegler.--Aug. 1865-Dec. 1871, J. H. McQuillen, G. J. Ziegler.--Jan. 1872-May 1891, J. W. White.--July 1891-Apr. 1930, E. C. Kirk (with L. P. Anthony, Dec. 1917-Apr. 1930).--May 1930-Dec. 1936, L. P. Anthony.Vols. 1-13 are called "new series."Merged in Jan. 1937 with: Journal of the American Dental Association, ISSN 1048-6364, to form: Journal of the American Dental Association and dental cosmos, ISSN 0375-8451
The distribution and stabilisation of dissolved Fe in deep-sea hydrothermal plumes
No full textWe have conducted a study of hydrothermal plumes overlying the Mid-Atlantic Ridge near 5° S to investigate whether there is a significant export flux of dissolved Fe from hydrothermal venting to the oceans. Our study combined measurements of plume-height Fe concentrations from a series of 6 CTD stations together with studies of dissolved Fe speciation in a subset of those samples. At 2.5 km down plume from the nearest known vent site dissolved Fe concentrations were 20 nM. This is much higher than would be predicted from a combination of plume dilution and dissolved Fe(II) oxidation rates, but consistent with stabilisation due to the presence of organic Fe complexes and Fe colloids. Using Competitive Ligand Exchange–Cathodic Stripping Voltammetry (CLE–CSV), stabilised dissolved Fe complexes were detected within the dissolved Fe fraction on the edges of one non-buoyant hydrothermal plume with observed ligand concentrations high enough to account for stabilisation of 4% of the total Fe emitted from the 5° S vent sites. If these results were representative of all hydrothermal systems, submarine venting could provide 12–22% of the global deep-ocean dissolved Fe budget
Radium isotopes as tracers of iron sources fueling a Southern Ocean phytoplankton bloom
No full textElevated levels of productivity in the wake of Southern Ocean island systems are common despite the fact that they are encircled by high-nutrient low-chlorophyll (HNLC) waters. In the Crozet Plateau region, it has been hypothesized that iron from island runoff or sediments of the plateau could be fueling the austral summer phytoplankton bloom. Here, we use radium isotopes to quantify the rates of surface-ocean iron supply fueling the bloom in the Crozet Plateau region. A 1-D eddy-diffusion-mixing model applied to a 228Ra profile (t1/2=5.75 years) at a station north of the islands suggests fast vertical mixing in the upper 300 m (Kz=11–100 cm2 s?1) with slower mixing between 300 and 1000 m (Kz=1.5 cm2 s?1). This estimate is discussed in the context of Kz derived from the CTD/LADCP data. In combination with the dissolved Fe profile at this location, we estimated a vertical flux of between 5.6 and 31 nmol Fe m?2 d?1. The cross-plateau gradients in the short-lived radium isotopes, 224Ra (t1/2=3.66 d) and 223Ra (t1/2=11.4 d), yielded horizontal eddy diffusivities (Kh) of 39 and 6.6 m2 s?1, respectively. If we assume that the islands (surface runoff) alone were supplying dissolved Fe to the bloom region, then the flux estimates range from 2.3 to 14 nmol Fe m?2 d?1. If the plateau sediments are considered a source of Fe, and conveyed to the bloom region through deep winter mixing combined with horizontal transport, then this flux may be as high as 64–390 nmol Fe m?2 d?1. Combined, these Fe sources are sufficient to initiate and maintain the annual phytoplankton bloom
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