Effects of rotation and sloping terrain on fronts of density current fronts

The initial stage of the adjustment of a gravity current to the effects of rotation with angular velocity f/2 is analysed using a short time analysis where Coriolis forces are initiated in an inviscid von Kármán–Benjamin gravity current front at tF=0. It is shown how, on a time-scale of order 1/f, as a result of ageostrophic dynamics, the slope and front speed UF are much reduced from their initial values, while the transverse anticyclonic velocity parallel to the front increases from zero to O(NH0), where N=g′/H0−−−−−√ is the buoyancy frequency, and g′=gΔρ/ρ0 is the reduced acceleration due to gravity. Here ρ0 is the density and Δρ and H0 are the density difference and initial height of the current. Extending the steady-state theory to account for the effect of the slope σ on the bottom boundary shows that, without rotation, UF has a maximum value for σ=\upi/6, while with rotation, UF tends to zero on any slope. For the asymptotic stage when ftF≫1, the theory of unsteady waves on the current is reviewed using nonlinear shallow-water equations and the van der Pol averaging method. Their motions naturally split into a ‘balanced’ component satisfying the Margules geostrophic relation and an equally large ‘unbalanced’ component, in which there is horizontal divergence and ageostrophic vorticity. The latter is responsible for nonlinear oscillations in the current on a time scale f−1, which have been observed in the atmosphere and field experiments. Their magnitude is mainly determined by the initial potential energy in relation to that of the current and is proportional to the ratio \it Bu−−−−−√=LR/R0, where LR=NH0/f is the Rossby deformation radius and R0 is the initial radius. The effect of slope friction also prevents the formation of a steady front. From the analysis it is concluded that a weak mean radial flow must be driven by the ageostrophic oscillations, preventing the mean front speed UF from halting sharply at ftF∼1. Depending on the initial value of LR/R0, physical arguments show that UF decreases slowly in proportion to (ftF)−1/2, i.e. UF/UF0=F(ftF,\it Bu). Thus the front only tends to the geostrophic asymptotic state of zero radial velocity very slowly (i.e. as ftF→∞) for finite values of LR/R0. However, as LR/R0→0, it reaches this state when ftF∼1. This analysis of the overall nonlinear behaviour of the gravity current is consistent with two two-dimensional non-hydrostatic (Navier–Stokes) and axisymmetric hydrostatic (shallow-water) Eulerian numerical simulations of the varying form of the rotating gravity current. When the effect of surface friction is considered, it is found that the mean movement of the front is significantly slowed. Furthermore, the oscillations with angular frequency f and the slow growth of the radius, when ftF≥1, are consistent with recent experiments

Rhetoric with Humor: An Analysis of Hispanic/Latino Comedians\u27 Uses of Humor

Hispanic/Latino comedians\u27 use of humor as argument is a rich environment to study. The relationship between the comedian (as the joke teller) and the audience (as the receivers of the joke) creates an environment where many topical boundaries fall, and the comedian is free to express him/herself without fear of persecution or ridicule. More specifically, this setting allows the comedian to use the platform as joke teller to communicate arguments to the audience through humor. Comedians who use humor rhetorically often communicate arguments about well-known stereotypes freely because audiences attend shows expecting to laugh. Using Kenneth Burke\u27s (1959) perspective by incongruity as a lenses, this study analyzes the strategies and meanings in the arguments made through humor created by George Lopez and Carlos Mencia from a rhetorical perspective. The primary goal is to create a method that communication scholars are able to apply not only to Hispanic/Latino comedians, but to the overall use of humorous messages with arguments. By establishing the importance of understanding messages created in a communicative setting where humor is expected, Lopez\u27 and Mencia\u27s strategies become clearer. In this case, this method revealed how Lopez and Mencia made strategic arguments through enthymemes and incongruity humor and how those uses of humor affect the stereotypical identities of the Hispanic/Latino population. The results of this study will be used to examine potential rhetorical strengths of using humor not only for Lopez and Mencia, but also for humor users in general

An Evaluation of the Operational Restrictions Imposed to Congonhas Airport by IAC 121-1013

The objective of this study is to propose a review of the operational restrictions imposed on Congonhas airport by IAC 121-1013, seeking a balance between flight safety and operational efficiency. The researchers calculated the landing performance (using specific software), taking into account particular aircraft system failures that increase landing distance. The results indicated that the measures imposed by the IAC have little or no effect on the operational safety increase. Additionally, the restrictions created operational complexity for the airport and reduced its efficiency by impacting airline costs. At the end of the study, the researchers suggest a reissue of the IAC based on the data presented

An Evaluation of the Operational Restrictions Imposed to Congonhas Airport by Civil Aviation Instruction121-1013

Due to aircraft accidents, in 2008, operational restrictions were imposed on Congonhas airport by IAC 121-1013. These restrictions sought to create a balance between flight safety and operational efficiency. The purpose of this research was to investigate the results of the operational restrictions. The researchers calculated the landing performance (using specific software), taking into account particular aircraft system failures that increase landing distance. The results indicated that the measures imposed by the IAC have little or no effect on operational safety. Additionally, the restrictions created operational complexity for the airport and reduced its efficiency by impacting airline costs. Finally, the researchers suggested a reissue of the IAC based on the data presented

A comparative analysis of cache memory architectures for the multiplus multiprocessor

This paper analyses some design altematives for the MULTIPLUS cache memory subsystem architecture. MUL TIPLUS is a high performance multiprocessor system under development at NCE/UFRJ. The analysis is carried out using a simu1ator which supports different cache configurations. The simulator experiments have been done under three different situations: a non-cache system and the use of write back and write through control policies. The graphical results show the system behaviour in relation to the average ratio of bus occupation and the average processor cycle length.Este trabalho analisa algumas alternativas de projeto para a arquitetura do sub-sistema de memória cache para o multiprocessador MULTIPLUS. O MULTIPLUS é um multiprocessador de alto desempenho em desenvolvimento no Núcleo de Computação Eletrônica da Universidade Federal do Rio de Janeiro (NCE/UFRJ). A análise foi realizada utilizando-se um simulador que suporta diferentes configurações de memórias cache. A simulação foi realizada utilizando-se três diferentes sistemas: sem memória cache, com cache utilizando políticas de controle do tipo write through e write back. Os resultados gráficos mostram o desempenho do sistema em relação a taxa média de ocupação dos barramentos e o tempo médio de duração do ciclo do processador

Oral health and nutritional characteristics of adults with morbid obesity: a multivariate analysis.

The relationship between oral health and nutritional aspects are complex, especially in individuals with chronic diseases and comorbidities, such as morbid obesity. Thus, the aim of the present study was to identify oral health and nutritional-related patterns in 113 individuals, aged 19–68 years (92 females), seeking treatment for morbid obesity. Sociodemographic variables and medical records were examined, in addition to the consumption of fruit, vegetables, candies, and processed foods. Measures of body mass index, neck, waist and hip, caries experience (DMFT index), Community Periodontal Index (CPI index), and salivary physicochemical aspects were gathered. Aspects of oral health-related quality of life and symptoms of dry mouth were evaluated by means of Oral Health Impact Profile (OHIP-14) and Xerostomia Inventory-XI questionnaires. K-means cluster analysis and, subsequently, comparisons between clusters (one-way ANOVA) were performed (α = 5%). Three clusters were generated: Cluster 1 (labeled “Young”; n = 77) was characterized by younger participants with higher BMI, who reported the use of distractors while eating, the smallest number of meals/day, and who consumed sweetened drinks and processed food the day before. Cluster 2 (labeled “Diabetic individuals”; n = 12) was characterized by older participants with the highest proportion of diabetic participants (100% were diabetic; 73% insulin users), lower BMI, higher DMFT index and OHIP-14 and xerostomia scores, and who reported having consumed fruit and vegetables the day before. Finally, Cluster 3 (labeled “Poor periodontal health”; n = 24) was characterized by participants with the worse periodontal condition (higher CPI), and lower salivary flow, pH, and buffer capacity. Cluster 1 and 2 were the groups that showed higher demand for nutritional and dietetic counseling, because of the poor eating behavior and higher serum glucose levels, respectively. On the other hand, Cluster 2 and 3 showed the higher demand for oral rehabilitation and dental treatment because of the loss of teeth and worse periodontal condition, respectively, besides the need for dietetic counseling. This sample of individuals with morbid obesity showed very unique oral-health and nutritional characteristics and special needs patterns that should be identified to adjust or change unhealthy habits, thus improving the assistance of this condition

ATITUDE AO ENDIVIDAMENTO E CONHECIMENTO FINANCEIRO: UM ESTUDO COM OS SERVIDORES DA UFSC

O intuito desta pesquisa é compreender quais os determinantes da atitude ao endividamento e do conhecimento financeiro de servidores da Universidade Federal de Santa Catarina (UFSC) se considerado variáveis socioeconômicas e demográficas. Com base nesses resultados, será possível identificar um perfil de risco (servidores mais propensos a apresentarem baixo conhecimento financeiro e elevada atitude ao endividamento) para o qual será direcionado o segundo objetivo deste estudo: elaborar uma proposta de um curso de educação financeira que se dedique a conceitos financeiros gerais, bem como foque nos temas que os servidores demonstrarem maiores dificuldade na pesquisa, possibilitando assim melhores decisões financeiras e consequentemente evitando as diversas consequências negativas decorrentes do desequilíbrio financeiro. Para atingir a estes objetivos foi aplicado um questionário pelo qual foi possível identificar que os colaboradores da UFSC possuem baixa atitude ao endividamento e elevado conhecimento financeiro. No entanto, ainda há aqueles com maior tendência a apresentarem baixa educação financeira e elevada atitude ao endividamento, sendo os demais resultados (teste t e anova) direcionados a identificação desses, os quais devem ser priorizados no curso de capacitação aqui proposto

Refraction of Electromagnetic Energy for Wave Packets Incident on a Negative Index Medium is Always Negative

We analyze refraction of electromagnetic wave packets on passing from an isotropic positive to an isotropic negative refractive index medium. We definitively show that in all cases the energy is always refracted negatively. For localized wave packets, the group refraction is also always negative.Comment: 5 pages, 3 figure

Advantages and disadvantages on photosynthesis measurement techniques: A review

Through photosynthesis, green plants and cyanobacteria are able to transfer sunlight energy to molecular reaction centers for conversion into chemical energy with nearly 100% efficiency. Speed is the key as the transfer of the solar energy takes place almost instantaneously such that little energy is wasted as heat. How photosynthesis achieves this near instantaneous energy transfer is a longstanding mystery that may have finally been solved. Measurements of this process are useful in order to understand how it might be controlled and how the phytomonitoring of plant development to increase productivity can be carried out. Techniques in this sense have evolved and nowadays several have been used for this purpose. Thus, the aim of this paper is to present a review of the various methods and principles that have been used in measuring photosynthesis presenting the advantages and disadvantages of various existing measurement methodologies in order to recommend the most appropriate method according to the needs of specific investigations