Seasonal variations of the physical and optical characteristics of Saharan Dust: results from the Dust outflow and Deposition to the Ocean (DODO) experiment

North African dust is important for climate through its direct radiative effect on solar and terrestrial radiation and its role in the biogeochemical system. The Dust Outflow and Deposition to the Ocean project (DODO) aimed to characterize the physical and optical properties of airborne North African dust in two seasons and to use these observations to constrain model simulations, with the ultimate aim of being able to quantify the deposition of iron to the North Atlantic Ocean. The in situ properties of dust from airborne campaigns measured during February and August 2006, based at Dakar, Senegal, are presented here. Average values of the single scattering albedo (0.99, 0.98), mass specific extinction (0.85 m^2 g^-1 , 1.14 m^2 g^-1 ), asymmetry parameter (0.68, 0.68), and refractive index (1.53--0.0005i,1.53--0.0014i) for the accumulation mode were found to differ by varying degrees between the dry and wet season, respectively. It is hypothesized that these differences are due to different source regions and transport processes which also differ between the DODO campaigns. Elemental ratios of Ca/Al were found to differ between the dry and wet season (1.1 and 0.5, respectively). Differences in vertical profiles are found between seasons and between land and ocean locations and reflect the different dynamics of the seasons. Using measurements of the coarse mode size distribution and illustrative Mie calculations, the optical properties are found to be very sensitive to the presence and amount of coarse mode of mineral dust, and the importance of accurate measurements of the coarse mode of dust is highlighted.

Using aircraft measurements to determine the refractive index of Saharan dust during the DODO Experiments

Much uncertainty in the value of the imaginary part of the refractive index of mineral dust contributes to uncertainty in the radiative effect of mineral dust in the atmosphere. A synthesis of optical, chemical and physical in-situ aircraft measurements from the DODO experiments during February and August 2006 are used to calculate the refractive index mineral dust encountered over West Africa. Radiative transfer modeling and measurements of broadband shortwave irradiance at a range of altitudes are used to test and validate these calculations for a specific dust event on 23 August 2006 over Mauritania. Two techniques are used to determine the refractive index: firstly a method combining measurements of scattering, absorption, size distributions and Mie code simulations, and secondly a method using composition measured on filter samples to apportion the content of internally mixed quartz, calcite and iron oxide-clay aggregates, where the iron oxide is represented by either hematite or goethite and clay by either illite or kaolinite. The imaginary part of the refractive index at 550 nm (ni550) is found to range between 0.0001 i to 0.0046 i, and where filter samples are available, agreement between methods is found depending on mineral combination assumed. The refractive indices are also found to agree well with AERONET data where comparisons are possible. ni550 is found to vary with dust source, which is investigated with the NAME model for each case. The relationship between both size distribution and ni550 on the accumulation mode single scattering albedo at 550 nm (ω0550) are examined and size distribution is found to have no correlation to ω0550, while ni550 shows a strong linear relationship with ω0550. Radiative transfer modeling was performed with different models (Mie-derived refractive indices, but also filter sampling composition assuming both internal and external mixing). Our calculations indicate that Mie-derived values of ni550 and the externally mixed dust where the iron oxide-clay aggregate corresponds to the goethite-kaolinite combination result in the best agreement with irradiance measurements. The radiative effect of the dust is found to be very sensitive to the mineral combination (and hence refractive index) assumed, and to whether the dust is assumed to be internally or externally mixed.

Psychotherapieforschung - Ist «Dodo Bird» en vogue?

Das «Dodo-Bird-Verdikt», Ende der achtziger Jahre Resultat einer Metaanalyse, stellte fest, dass sich die etablierten Psychotherapieschulen in ihrer Wirksamkeit statistisch nicht bedeutsam unterscheiden. Der Begriff hat seinen Ursprung in «Alice im Wunderland», wo ein Dodo den Vorschlag macht, ein Rennen zu veranstalten, bei dem am Ende alle gewinnen, weil es kein Ziel gibt und auch die Zeit nicht gemessen wird. – Ist die These unter Akteuren der Psychotherapie en vogue? Ein Kommentar.

The Drosophila melanogaster dodo (dod) gene, conserved in humans, is functionally interchangeable with the ESS1 cell division gene of Saccharomyces cerevisiae.

We have sequenced the region of DNA adjacent to and including the flightless (fli) gene of Drosophila melanogaster and molecularly characterized four transcription units within it, which we have named tweety (twe), flightless (fli), dodo (dod), and penguin (pen). We have performed deletion and transgenic analysis to determine the consequences of the quadruple gene removal. Only the flightless gene is vital to the organism; the simultaneous absence of the other three allows the overriding majority of individuals to develop to adulthood and to fly normally. These gene deletion results are evaluated in the context of the redundancy and degeneracy inherent in many genetic networks. Our cDNA analyses and data-base searches reveal that the predicted dodo protein has homologs in other eukaryotes and that it is made up of two different domains. The first, designated WW, is involved in protein-protein interactions and is found in functionally diverse proteins including human dystrophin. The second is involved in accelerating protein folding and unfolding and is found in Escherichia coli in a new family of peptidylprolyl cis-trans isomerases (PPIases; EC 5.2.1.8). In eukaryotes, PPIases occur in the nucleus and the cytoplasm and can form stable associations with transcription factors, receptors, and kinases. Given this particular combination of domains, the dodo protein may well participate in a multisubunit complex involved in the folding and activation of signaling molecules. When we expressed the dodo gene product in Saccharomyces cerevisiae, it rescued the lethal phenotype of the ESS1 cell division gene.

Annotated record of the detailed examination of Mn deposits from DODO Expedition stations

The cores and dredges described in this report were taken on the DODO Expedition in May 1964 until December 1964 by the Scripps Institution of Oceanography from the R/V Argo. A total of 290 cores and dredges were recovered and are available at Scripps for sampling and study.

Dodo the second.

Mode of access: Internet.

Dodo; a detail of the day,

Mode of access: Internet.

A Review of the Dodo and its Ecosystem: Insights from a Vertebrate Concentration Lagerstätte in Mauritius

The dodo Raphus cucullatus Linnaeus, 1758, an extinct and flightless, giant pigeon endemic to Mauritius, has fascinated people since its discovery, yet has remained surprisingly poorly known. Until the mid-19th century, almost all that was known about the dodo was based on illustrations and written accounts by 17th century mariners, often of questionable accuracy. Furthermore, only a few fragmentary remains of dodos collected prior to the bird’s extinction exist. Our understanding of the dodo’s anatomy was substantially enhanced by the discovery in 1865 of subfossil bones in a marsh called the Mare aux Songes, situated in southeastern Mauritius. However, no contextual information was recorded during early excavation efforts, and the majority of excavated material comprised larger dodo bones, almost all of which were unassociated. Here we present a modern interdisciplinary analysis of the Mare aux Songes, a 4200-year-old multitaxic vertebrate concentration Lagerst€atte. Our analysis of the deposits at this site provides the first detailed overview of the ecosystem inhabited by the dodo. The interplay of climatic and geological conditions led to the exceptional preservation of the animal and associated plant remains at the Mare aux Songes and provides a window into the past ecosystem of Mauritius. This interdisciplinary research approach provides an ecological framework for the dodo, complementing insights on its anatomy derived from the only associated dodo skeletons known, both of which were collected by Etienne Thirioux and are the primary subject of this memoir.

Cognitive behaviour therapy (CBT) for the treatment of co-occurring depression and substance use : current evidence and directions for future research

Issues and Approach: The high rates of co-occurring depression and substance use, and the negative impact of this on illness course and outcomes have been well established. Despite this, few clinical trials have examined the efficacy of cognitive behaviour therapy (CBT). This paper systematically reviews these clinical trials, with an aim of providing recommendations for how future research can develop a more robust evidence base for the treatment of these common comorbidities. Leading electronic databases, including PubMed (ISI) and PsychINFO (CSA), were searched for peer-reviewed journal articles using CBT for the treatment of co-occurring depression and substance use. Of the 55 articles identified, 12 met inclusion criteria and were included in the review. ---------- Key Findings: There is only a limited evidence for the effectiveness of CBT either alone or in combination with antidepressant medication for the treatment of co-occurring depression and substance use. While there is support for the efficacy of CBT over no treatment control conditions, there is little evidence that CBT is more efficacious than other psychotherapies. There is, however, consistent evidence of improvements in both depression and substance use outcomes, regardless of the type of treatment provided and there is growing evidence that that the effects of CBT are durable and increase over time during follow up. ---------- Conclusions. Rather than declaring the ‘dodo bird verdict’ that CBT and all other psychotherapies are equally efficacious, it would be more beneficial to develop more potent forms of CBT by identifying variables that mediate treatment outcomes.

Desenvolvimento de sensores de fibra óptica para monitorização de compostos orgânicos voláteis em ambientes industriais

O objectivo geral deste trabalho consistiu no desenvolvimento de novos sensores químicos de fibra óptica (OF) para análise de compostos orgânicos voláteis (VOCs) em ambientes industriais. A componente de detecção dos sensores desenvolvidos é constituída por uma pequena secção de fibra óptica revestida com um filme de polímero. A morfologia dos filmes poliméricos foi analisada e caracterizada por microscopia electrónica de varrimento (SEM), sendo a espessura dos filmes determinada por espectroscopia de retrodispersão de Rutherford (RBS, acrónimo do inglês Rutherford backscattering spectrometry). O desempenho analítico dos sensores de OF foi avaliado relativamente a diferentes parâmetros operacionais, tais como, concentração da solução de revestimento, técnica de deposição do filme polimérico, temperatura da célula de injecção, temperatura de cura do material polimérico, caudal do gás de arraste, comprimento de onda e frequência de funcionamento do laser, configurações estruturais da célula de injecção e do tubo analítico. Foram desenvolvidos dois sensores de OF a operar na região do infravermelho para determinação de diferentes classes de VOCs, nomeadamente hidrocarbonetos aromáticos, clorados e alifáticos, além de álcoois. Os sensores de OF desenvolvidos apresentaram adequadas características analíticas em termos de sensibilidade, linearidade, repetitibilidade e reprodutibilidade do sinal analítico, sendo o tempo de resposta de aproximadamente 30 segundos. Foi também desenvolvido um sensor de OF para especiação de benzeno, tolueno e o-xileno a operar na região do visível (635 - 650 nm), tendo sido aplicado à análise de amostras reais de ar de uma indústria de solventes. Relativamente à monitorização de VOCs em ambientes industriais, foi desenvolvido um sensor de OF para monitorização in situ e de forma remota (até uma distância máxima de 60 metros do local de amostragem) de benzeno, tolueno, etilbenzeno, p-xileno, m-xileno e o-xileno (BTEX), utilizando um díodo laser a 1550 nm. O desempenho analítico do sensor desenvolvido foi comparado, para a determinação de BTEX, com a cromatografia gasosa acoplada à detecção com ionização de chama (GC-FID). Foram ainda desenvolvidos dois detectores de fibra óptica acoplados a um cromatógrafo de gás para especiação de álcoois e hidrocarbonetos aromáticos. A metodologia desenvolvida baseada em cromatografia gasosa acoplada a um detector de fibra óptica (GC-OF) foi aplicada à análise de amostras reais de ar de uma indústria de solventes, comparando os respectivos resultados com os obtidos por GC-FID. Por fim foi efectuado um estudo visando a obtenção de um modelo geral para a resposta analítica dos sensores de fibra óptica desenvolvidos.

Avaliação de qualidade de energia de um sistema fotovoltaico numa rede elétrica

Dissertação para obtenção do grau de Mestre em Engenharia Electrotécnica Ramo de Energia

Recommandations portant sur la prise en charge optimale en physiothérapie de la clientèle pédiatrique atteinte de torticolis musculaire congénital

Travail d'intégration réalisé dans le cadre du cours PHT-6113.