Surface shear stress dependence of gas transfer velocity parameterizations using DNS

Air-water gas-exchange is studied in direct numerical simulations (DNS) of free-surface flows driven by natural convection and weak winds. The wind is modeled as a constant surface-shear-stress and the gas-transfer is modeled via a passive scalar. The simulations are characterized via a Richardson number Ri=Bν/u*4 where B, ν, and u* are the buoyancy flux, kinematic viscosity, and friction velocity respectively. The simulations comprise 0<Ri<∞ ranging from convection-dominated to shear-dominated cases. The results are used to: (i) evaluate parameterizations of the air-water gas-exchange, (ii) determine, for a given buoyancy flux, the wind speed at which gas transfer becomes primarily shear driven, and (iii) find an expression for the gas-transfer velocity for flows driven by both convection and shear. The evaluated gas transfer-velocity parametrizations are based on either the rate of turbulent kinetic energy dissipation, the surface flow-divergence, the surface heat-flux, or the wind-speed. The parametrizations based on dissipation or divergence show an unfavorable Ri dependence for flows with combined forcing whereas the parametrization based on heat-flux only shows a limited Ri dependence. The two parametrizations based on wind speed give reasonable estimates for the transfer-velocity, depending however on the surface heat-flux. The transition from convection- to shear-dominated gas-transfer-velocity is shown to be at Ri≈0.004. Furthermore, the gas-transfer is shown to be well represented by two different approaches: (i) additive forcing expressed as kg,sum=AShearu*Ri/Ric+11/4Sc-n where Ric=AShear/ABuoy4, and (ii) either buoyancy or shear dominated expressed as, kg=ABuoyBν1/4Sc-n, Ri>Ric or kg=Ashearu*Sc-n, Ri<Ric. Here ABuoy=0.4 and AShear=0.1 are constants, and n is an exponent that depends on the water surface-characteristics

Neuromorphic Detection of Vowel Representation Spaces

In this paper a layered architecture to spot and characterize vowel segments in running speech is presented. The detection process is based on neuromorphic principles, as is the use of Hebbian units in layers to implement lateral inhibition, band probability estimation and mutual exclusion. Results are presented showing how the association between the acoustic set of patterns and the phonologic set of symbols may be created. Possible applications of this methodology are to be found in speech event spotting, in the study of pathological voice and in speaker biometric characterization, among others

Scoping studies to establish the capability and utility of a real-time bioaerosol sensor to characterise emissions from environmental sources

A novel dual excitation wavelength based bioaerosol sensor with multiple fluorescence bands called Spectral Intensity Bioaerosol Sensor (SIBS) has been assessed across five contrasting outdoor environments. The mean concentrations of total and fluorescent particles across the sites were highly variable being the highest at the agricultural farm (2.6 cm−3 and 0.48 cm−3, respectively) and the composting site (2.32 cm−3 and 0.46 cm−3, respectively) and the lowest at the dairy farm (1.03 cm−3 and 0.24 cm−3, respectively) and the sewage treatment works (1.03 cm−3 and 0.25 cm−3, respectively). In contrast, the number-weighted fluorescent fraction was lowest at the agricultural site (0.18) in comparison to the other sites indicating high variability in nature and magnitude of emissions from environmental sources. The fluorescence emissions data demonstrated that the spectra at different sites were multimodal with intensity differences largely at wavelengths located in secondary emission peaks for λex 280 and λex 370. This finding suggests differences in the molecular composition of emissions at these sites which can help to identify distinct fluorescence signature of different environmental sources. Overall this study demonstrated that SIBS provides additional spectral information compared to existing instruments and capability to resolve spectrally integrated signals from relevant biological fluorophores could improve selectivity and thus enhance discrimination and classification strategies for real-time characterisation of bioaerosols from environmental sources. However, detailed lab-based measurements in conjunction with real-world studies and improved numerical methods are required to optimise and validate these highly resolved spectral signatures with respect to the diverse atmospherically relevant biological fluorophores

Image Feature Extraction Acceleration

Image feature extraction is instrumental for most of the best-performing algorithms in computer vision. However, it is also expensive in terms of computational and memory resources for embedded systems due to the need of dealing with individual pixels at the earliest processing levels. In this regard, conventional system architectures do not take advantage of potential exploitation of parallelism and distributed memory from the very beginning of the processing chain. Raw pixel values provided by the front-end image sensor are squeezed into a high-speed interface with the rest of system components. Only then, after deserializing this massive dataflow, parallelism, if any, is exploited. This chapter introduces a rather different approach from an architectural point of view. We present two Application-Specific Integrated Circuits (ASICs) where the 2-D array of photo-sensitive devices featured by regular imagers is combined with distributed memory supporting concurrent processing. Custom circuitry is added per pixel in order to accelerate image feature extraction right at the focal plane. Specifically, the proposed sensing-processing chips aim at the acceleration of two flagships algorithms within the computer vision community: the Viola-Jones face detection algorithm and the Scale Invariant Feature Transform (SIFT). Experimental results prove the feasibility and benefits of this architectural solution.Ministerio de Economía y Competitividad TEC2012-38921-C02, IPT-2011- 1625-430000, IPC-20111009Junta de Andalucía TIC 2338-2013Xunta de Galicia EM2013/038Office of NavalResearch (USA) N00014141035

Semi-discrete linear hyperbolic polyharmonic flows of closed polygons

We consider the damped hyperbolic motion of polygons by a linear semi-discrete analogue of polyharmonic curve diffusion. We show that such flows may transition any polygon to any other polygon, reminiscent of the Yau problem of evolving one curve to another by a curvature flow, before converging exponentially to a point that, under appropriate rescaling, is a planar basis polygon. We also consider a hyperbolic linear semi-discrete flow of the Yau curvature difference flow, where a polygonal curve is able to flow to any other such that we get convergence to the target polygon in infinite time

PALAVRAS PROIBIDAS: UMA LEITURA DE “O INCOMPREENDIDO” DE CARRY VAN BRUGGEN

Resumo: Utilizando como mote o conto “O incompreendido” da escritora holandesa Caroline Lea de Haan (1881-1932), o artigo discute a questão do assimilacionismo e do antissemitismo, tendo como base os textos Antissemitismo e O judeu como pária de Hannah Arendt (1906-1975) e Do anti-sionismo ao anti-semitismo Leon Poliakov (1910-1997)

Um número no Lager: repercussões e ressonâncias a partir da literatura da Shoah

The following study is a proposition; as in the words of Paul Celan, to say something, only putting it in different ways. What would one dare to say? How would it be possible to think about the Shoah withouth an analysys of forms and numbers? The starting point was a quote from Primo Levi, who raised the question: what was it like for a jewish to have his or her name changed for a number in the nazi camps? As I assumed it was not an easy route to take, I opted for a kind of writing that would allow the use of images from the Lager brought from my readings of the source material. Initial readings started with Walter Benjamin and Gaston Bachelard, but after verifying that the concept of evil was deeply entwined in the jewish texts about name and soul, Hannah Arendt soon became another fundamental entry in my theoretical framework; Giorgio Agamben and Léon Poliakov also helped with the issues on judaism. The need to think about alterity became an imperative when I realized that Primo Levi was not referring to the human being only in a political level; thus the discussion about name and soul. The result is an amalgam of different authors: Walter Benjamin, Hannah Arendt, Emmanuel Lévinas, Gaston Bachelard, Gershom Scholem, as well as the reports and narratives. Therefore, this work stands as a type of "constellation writing", as the result of following the trail of thought of this six-pointed star: a reading on the Shoah Literature.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)O estudo é uma proposição, como nas palavras do poeta Celan, dizer de outra forma que não assim. Dizer o quê? Como se pode pensar a literatura da Shoah sem cair numa análise de formas e números? O ponto de partida foi uma citação de Primo Levi, que despertou a questão: o que significou para o judeu a substituição do nome pelo número no campo de concentração nazista? Assumindo que não seria um caminho tão simples, optei por uma escrita que viabilizasse o uso das imagens do Lager trazidas pela leitura dos relatos. As escolhas teóricas após as leituras iniciais foram Walter Benjamin e Gaston Bachelard. Após verificar nos textos sobre o nome e a alma no judaísmo que a questão do mal estava entrelaçada, Hannah Arendt deixou de ser uma opção para comentar a questão judaica e entrou como leitura fundamental. Entre as leituras sobre a questão judaica entraram Giorgio Agamben e Léon Poliakov. Surgiu com isso a necessidade de pensar sobre a alteridade, por entender que a questão levantada pelo trecho de Primo Levi implicava a pessoa não apenas do ponto de vista político - por isso a discussão sobre o nome e alma. O resultado é o entrelaçamento desses autores: Walter Benjamin, Hannah Arendt, Emmanuel Lévinas, Gaston Bachelard, Gershom Scholem com os relatos. Juntos, numa escrita em constelação esses grandes pensadores judeus formam a minha estrela de seis pontas, uma leitura sobre a literatura da Shoah

The Role of Trait Mindfulness in the Association between Loneliness and Psychological Distress

Objectives Loneliness is associated with elevated psychological distress. This study examined whether trait mindfulness mediates or moderates the positive association between loneliness and psychological distress. Method A convenience sample of 297 adults (79.1% female, 20.5% male) aged 18 to 75 years (M =38.38, SD =11.31) completed an online questionnaire that assessed loneliness, trait mindfulness and its facets (Non-Judging, Awareness, NonReactivity, Describing, Observing), and psychological distress (depression, anxiety, stress). Results Mediation analysis identifed an indirect path from loneliness to psychological distress through trait mindfulness. Participants who reported greater loneliness reported lower trait mindfulness that, in turn, tended to associate with greater psychological distress. Multiple mediation analysis found indirect paths via Non-Judging, Awareness, Non-Reactivity, and Describing. Moderation analysis found that the association between loneliness and psychological distress was signifcant for participants with low trait mindfulness but non-signifcant for those with high trait mindfulness. However, analysis of the mindfulness facets as simultaneous moderators found that no facet individually moderated the association. Rather, all contributed to a cumulative interactive role of the composite mindfulness construct. A supplementary analysis found that lower levels of loneliness mediated the association between mindfulness and psychological distress. Conclusions A tendency to respond to loneliness with low levels of Non-Judging, Awareness, Non-Reactivity, and Describing may exacerbate distress. These results suggest that future research may benefit from investigating whether interventions that increase these mindfulness facets may mitigate psychological distress associated with loneliness

Diálogos com o homem imaginário: pensando o uso de imagens no ensino de sociologia

Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorO texto aborda a questão do cinema como operador cognitivo nas aulas de Sociologia no Ensino Médio. Apresenta um pequeno histórico da disciplina com a finalidade de dar um panorama mínimo de compreensão do contexto em que se insere o problema a ser discutido. A concepção de educação, dentro da teoria da complexidade, tal como difundida por Edgar Morin em livros dedicados a pensar a educação é a base para a discussão. Busca-se pensar uma educação para a compreensão da diversidade sem desconsiderar a unidade do humano (sapiens demens). O cinema entra como uma mediação para essa finalidade, haja vista que sua utilização mobiliza a subjetividade amplificando as possibilidades de aprendizagem sem tanta fragmentação e reducionismo do complexo ao simples. As imagens são pensadas a partir da concepção de Gaston Bachelard, com a noção de ressonância e repercussão apresentada em ―A poética do espaço