Internal solitary waves in the Red Sea : an unfolding mystery

Author Posting. © The Oceanography Society, 2012. This article is posted here by permission of The Oceanography Society for personal use, not for redistribution. The definitive version was published in Oceanography 25, no. 2 (2012): 96-107, doi:10.5670/oceanog.2012.45.The off-shelf region between 16.0° and 16.5°N in the southern Red Sea is identified as a new hotspot for the occurrence of oceanic internal solitary waves. Satellite observations reveal trains of solitons that, surprisingly, appear to propagate from the center of the Red Sea, where it is deepest, toward the continental shelf, but they do not survive as coherent structures over the shelf. These solitons are characterized by coherent crest lengths exceeding 80 km and crest-to-crest distances of more than 2 km, compatible with signatures of large-amplitude solitary waves. Despite the fact that these Red Sea solitons have large amplitudes, they appear to be generated by very weak surface tides. Tidal current velocity is only about 5 cm s–1 over the shelf, much weaker than over other ocean shelves where similar solitary waves have been reported. The appearance of these waves over this particular geographical stretch suggests generation by a locally amplified internal tide on the main pycnocline. We consider three possible explanations for soliton generation in the Red Sea: interfacial tide resonance, local generation by internal tidal beams generated at the shelf breaks, and local generation by internal tidal beams generated at the shelf breaks but first amplified by repeated focusing reflections

Solid granite used as ornamental stones in the northeastern region of the State of Amazonas, Brazil: an investment perspective for the City of Manaus

O crescimento populacional de Manaus tem impulsionado o setor de rochas ornamentais e revestimentos a buscar matéria-prima de qualidade e beleza (granitos, gnaisses, mármores, etc.) na região sudeste do país a um custo elevado em até seis vezes. Entretanto a região nordeste do Amazonas hospeda maciços graníticos paleoproterozóicos com características ornamentais, os quais têm sido extraídos apenas para a produção de brita. Esse trabalho apresenta informações texturais, petrográficas, geoquímicas e de índices tecnológicos (porosidade, densidade, absorção d'água, compressão uniaxial, pulsos ultra-sônicos, resistência à flexão e desgaste Amsler) obtidas em cinco maciços graníticos expostos no nordeste do Amazonas. Tais informações sugerem que esses maciços graníticos podem ser utilizados como rochas ornamentais, porém em ambientes de moderado trânsito, baixa umidade e livres de ataques ácidos. Considerando os parâmetros técnicos favoráveis e a relativa proximidade das pedreiras da cidade de Manaus (cerca de 140 a 240 km), a qual é um centro consumidor com 2 milhões de habitantes, o investimento no setor extrativista de rochas com fins ornamentais na região nordeste do Amazonas torna-se uma opção, no mínimo, interessante para o setor empresarial.The population increase of the City of Manaus has propelled the ornamental stones business sector to procure raw-material of quality and beauty (granites, gneisses, marble, etc.) in the southeastern region of Brazil at a cost up to six times more expensive. However, the northeastern region of the State of Amazonas hosts paleoproterozoic granitic massifs with great potential for use as ornamental stones, which have onely been extracted for crushed-stone production. This paper presents the textural, petrographic, and geochemical characteristics, as well as technological indices (porosity, density, water absorption, uniaxial compression, ultrasonic pulses, resistance to flexion and Amsler degeneration) for samples from five granitic massifs exposed in the northeastern region of the State of Amazonas. The obtained data suggest that the granite massifs can be used as ornamental stones, but applicable in places with moderate transit, low humidity and free of acidic attacks. Considering the favorable technical parameters and the relative proximity of the granite massifs to the City of Manaus (about 140 to 240 km), which is a consumer centre with 2 million inhabitants, the investment in the extraction of ornamental stones in the northeast of Amazonas becomes an option, at least, interesting for the business sector

Multilevel analysis in CSCL Research

Janssen, J., Erkens, G., Kirschner, P. A., & Kanselaar, G. (2011). Multilevel analysis in CSCL research. In S. Puntambekar, G. Erkens, & C. Hmelo-Silver (Eds.), Analyzing interactions in CSCL: Methods, approaches and issues (pp. 187-205). New York: Springer. doi:10.1007/978-1-4419-7710-6_9CSCL researchers are often interested in the processes that unfold between learners in online learning environments and the outcomes that stem from these interactions. However, studying collaborative learning processes is not an easy task. Researchers have to make quite a few methodological decisions such as how to study the collaborative process itself (e.g., develop a coding scheme or a questionnaire), on the appropriate unit of analysis (e.g., the individual or the group), and which statistical technique to use (e.g., descriptive statistics, analysis of variance, correlation analysis). Recently, several researchers have turned to multilevel analysis (MLA) to answer their research questions (e.g., Cress, 2008; De Wever, Van Keer, Schellens, & Valcke, 2007; Dewiyanti, Brand-Gruwel, Jochems, & Broers, 2007; Schellens, Van Keer, & Valcke, 2005; Strijbos, Martens, Jochems, & Broers, 2004; Stylianou-Georgiou, Papanastasiou, & Puntambekar, chapter #). However, CSCL studies that apply MLA analysis still remain relatively scarce. Instead, many CSCL researchers continue to use ‘traditional’ statistical techniques (e.g., analysis of variance, regression analysis), although these techniques may not be appropriate for what is being studied. An important aim of this chapter is therefore to explain why MLA is often necessary to correctly answer the questions CSCL researchers address. Furthermore, we wish to highlight the consequences of failing to use MLA when this is called for, using data from our own studies

Experience report: training in the first aid of academics of the Pedagogy course

This project aimed to disseminate knowledge about the basic first aid concepts for the Undergraduate Pedagogy course and to strengthen the empowerment of these academics. Eight students from the eighth phase of the pedagogy course participated in the project. A total of six meetings were held with theoretical and practical classes located at the official campus of the Federal University of the South Frontier (UFFS). At the end of the project, a theoretical test was carried out with objective questions to evaluate the evolution of the knowledge of the students and a simulation for their practical evaluation. In this last test, it was left a space for a poll of a dissertation character, in order to evaluate in a more specific way the project. By expanding the knowledge of this subject to society, there is in a way a contribution to the reduction of health problems. These scientifically grounded knowledge can help save lives. The project was carried out during the months of August to December of 2016

Capturing Community Context of Human Response to Forest Disturbance by Insects: A Multi-Method Assessment

The socioeconomic and environmental features of local places (community context) influence the relationship between humans and their physical environment. In times of environmental disturbance, this community context is expected to influence human perceptual and behavioral responses. Residents from nine Colorado communities experiencing a large outbreak of mountain pine beetles (Dendroctonus ponderosae) were surveyed in 2007. Multiple analytic methods including ordinary least squares regression and multilevel modeling techniques were used to evaluate a community-context conceptual model of factors influencing individual actions in response to forest disturbance by beetles. Results indicated that community biophysical and socioeconomic characteristics had important impacts on participation in beetle-related actions and influenced the relationships of individual-level variables in the conceptual model with beetle-related activities. Our findings have implications for natural resource management and policy related to forest disturbances, and for developing a methodology appropriate to measure the general community context of human-environment interactions

The effect of fluid resuscitation on the effective circulating volume in patients undergoing liver surgery: a post-hoc analysis of a randomized controlled trial

To assess the significance of an analogue of the mean systemic filling pressure (Pmsa) and its derived variables, in providing a physiology based discrimination between responders and non-responders to fluid resuscitation during liver surgery. A post-hoc analysis of data from 30 patients undergoing major hepatic surgery was performed. Patients received 15 ml kg(-1) fluid in 30 min. Fluid responsiveness (FR) was defined as an increase of 20% or greater in cardiac index, measured by FloTrac-Vigileo((R)). Dynamic preload variables (pulse pressure variation and stroke volume variation: PPV, SVV) were recorded additionally. Pvr, the driving pressure for venous return (=Pmsa-central venous pressure) and heart performance (EH; Pvr/Pmsa) were calculated according to standard formula. Pmsa increased following fluid administration in responders (n = 18; from 13 +/- 3 to 17 +/- 4 mmHg, p < 0.01) and in non-responders (n = 12; from 14 +/- 4 to 17 +/- 4 mmHg, p < 0.01). Pvr, which was lower in responders before fluid administration (6 +/- 1 vs. 7 +/- 1 mmHg; p = 0.02), increased after fluid administration only in responders (from 6 +/- 1 to 8 +/- 1 mmHg; p < 0.01). EH only decreased in non-responders (from 0.56 +/- 0.17 to 0.45 +/- 0.12; p < 0.05). The area under the receiver operating characteristics curve of Pvr, PPV and SVV for predicting FR was 0.75, 0.73 and 0.72, respectively. Changes in Pmsa, Pvr and EH reflect changes in effective circulating volume and heart performance following fluid resuscitation, providing a physiologic discrimination between responders and non-responders. Also, Pvr predicts FR equivalently compared to PPV and SVV, and might therefore aid in predicting FR in case dynamic preload variables cannot be used

Self-organization in the olfactory system: one shot odor recognition in insects

We show in a model of spiking neurons that synaptic plasticity in the mushroom bodies in combination with the general fan-in, fan-out properties of the early processing layers of the olfactory system might be sufficient to account for its efficient recognition of odors. For a large variety of initial conditions the model system consistently finds a working solution without any fine-tuning, and is, therefore, inherently robust. We demonstrate that gain control through the known feedforward inhibition of lateral horn interneurons increases the capacity of the system but is not essential for its general function. We also predict an upper limit for the number of odor classes Drosophila can discriminate based on the number and connectivity of its olfactory neurons

Cylindrical fractional Brownian motion in Banach spaces

In this article we introduce cylindrical fractional Brownian motions in Banach spaces and develop the related stochastic integration theory. Here a cylindrical fractional Brownian motion is understood in the classical framework of cylindrical random variables and cylindrical measures. The developed stochastic integral for deterministic operator valued integrands is based on a series representation of the cylindrical fractional Brownian motion, which is analogous to the Karhunen-Loève expansion for genuine stochastic processes. In the last part we apply our results to study the abstract stochastic Cauchy problem in a Banach space driven by cylindrical fractional Brownian motion