119 research outputs found

    NanoRocks: Design and Performance of an Experiment Studying Planet Formation on the International Space Station

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    In an effort to better understand the early stages of planet formation, we have developed a 1.5U payload that flew on the International Space Station (ISS) in the NanoRacks NanoLab facility between September 2014 and March 2016. This payload, named NanoRocks, ran a particle collision experiment under long-term microgravity conditions. The objectives of the experiment were (a) to observe collisions between mm-sized particles at relative velocities of <<1~cm/s, and (b) to study the formation and disruption of particle clusters for different particle types and collision velocities. Four types of particles were used: mm-sized acrylic, glass, and copper beads, and 0.75 mm-sized JSC-1 lunar regolith simulant grains. The particles were placed in sample cells carved out of an aluminum tray. This tray was attached to one side of the payload casing with three springs. Every 60~s, the tray was agitated and the resulting collisions between the particles in the sample cells were recorded by the experiment camera. During the 18 months the payload stayed on ISS, we obtained 158 videos, thus recording a great number of collisions. The average particle velocities in the sample cells after each shaking event were around 1 cm/s. After shaking stopped, the inter-particle collisions damped the particle kinetic energy in less than 20~s, reducing the average particle velocity to below 1 mm/s, and eventually slowing them to below our detection threshold. As the particle velocity decreased, we observed the transition from bouncing to sticking collisions. We recorded the formation of particle clusters at the end of each experiment run. This paper describes the design and performance of the NanoRocks ISS payload.Comment: 8 pages, 8 figure

    Matkalla kotiin:asukkaan tarpeisiin perustuvan pientalon suunnittelun kulku

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    TiivistelmĂ€. TĂ€mĂ€ arkkitehtuurin diplomityö tarkastelee asukkaalle tilaustyönĂ€ toteutettavan pientalon suunnitteluprosessia. TĂ€llainen talo perustuu asukkaan omiin tarpeisiin ja toiveisiin. Niiden tunnistaminen ja dokumentointi muodostavat ensimmĂ€isen osan tĂ€stĂ€ työstĂ€. Pientalo on nimensĂ€ mukaisesti pieni rakennushanke. Taloudellisesti ja ekologisesti on jĂ€rkevÀÀ, ettĂ€ se toteutetaan rakennustuotteista, joita on saatavana valmiina. TĂ€mĂ€n työn seuraavassa vaiheessa valitaan mieluisat ja tarkoitukseen sopivat rakennusmateriaalit ja -tuotteet. Niiden ominaisuudet halutaan ottaa huomioon alusta asti talon suunnittelussa. Pientalon suunnittelusta syntyy kokonaisuus, jossa paikka, asukkaan tarpeet ja toiveet sekĂ€ kĂ€ytettĂ€vĂ€t rakennusmateriaalit vaikuttavat siihen, mitĂ€ valintoja arkkitehdillĂ€ on mahdollisuus tehdĂ€. TĂ€mĂ€n työn pientalon suunnittelun vĂ€livaiheita ei esitetĂ€ itse työssĂ€. LiitteenĂ€ oleva suunnittelupĂ€ivĂ€kirja antaa viitteitĂ€ siitĂ€, miten suunnittelu eteni. Lopuksi työssĂ€ tarkastellaan, miten asukkaiden tarpeet ja toiveet onnistuttiin ottamaan huomioon. TĂ€mĂ€ talo suunniteltiin itselle, joten asukkaiden tarpeet ja toiveet ovat tiedossa parhaalla mahdollisella tavalla.Abstract. This master’s thesis of architecture takes a view of the planning process of a single-family house that is tailor-made for it’s householder. Such a house is based on householder’s personal needs and desires. How to identify and document these, that is examined in the first part of this work. A single-family house is a rather modest construction project. It is reasonable that it is carried out by utilizing standard commercial building products. To choose the pleasing and suitable materials and building products is the next phase of this work. Their qualities are wanted to take into account during the planning process. The designing process of the single-family house turns into a ensemble consisting of the place of the house, the needs and desires of the householder and the chosen materials. They together have an impact on the choices that available for the architect. The interim stages of the design process in this work are not showed in the actual paper. Instead, the attached design diary illustrates the phases of the planning. In the last phase of the work, it is examined how well the needs and desires are taken into account in the design. This house was designed for the author’s family, so the needs and desires are surely well known

    A southern bottlenose whale examined in the Antarctic

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    This paper mainly concerns the dissection of a lactating female southern bottlenose whale Hyperoodon planifrons especially shot and worked up for the author in the Antarctic 61°09'S, 86°44'E on 10 March 1948. The skeleton is in the British Museum (Natural History). A comparison with what is known of the female northern bottlenose whale H. ampullatus shows no differences in morphometry, body colour, external characters, digestive system and reproductive system, parasites and the vertebral formula and the digital formula of the flipper. There remain acknowledged differences in the skull which may be reduced or perhaps even disappear when further comparisons are attempted between skulls from males and females of similar ages. There is also the confusion when identifying ziphiid whales at sea. These observations have suggested to the author that there may be only one Hyperoodon species with a continuous distribution north and south. But Dalebout et al. (2004), applying DNA sequencies in molecular taxonomy, have now shown that all 21 species of ziphiid whales are valid

    Trees for Food and Timber: are community interests in conflict with those of timber concessions in the Congo Basin?

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    Much of the Congo Basin is managed for timber from dozens of species. More than 60% also produce non-timber products, including foods. For five multiple use tree species in Cameroon, Democratic Republic of Congo (DRC) and Gabon (Entandrophragma cylindricum, Baillonella toxisperma, Erythrophleum suaveloens, Dacryodes buettneri and Gambeya lacourtiana), we studied gathering and consumption by communities, edible caterpillars hosted, the densities of trees around villages and in concessions and the impacts of timber harvesting . We also studied the consumption of forest foods and the nutritional values of fruits and seeds of various tree species. Villagers walked up to six km during day trips to collect fruits or caterpillars, gathering from concessions if the village was within or near it. When foods were gathered from trees smaller than the cutting diameter (which varied by country and species), there was no conflict with timber harvesting. However, the volume of edible caterpillars hosted increased with diameter and harvestable trees were the most productive. Caterpillars, tree fruits and seeds provide fats, vitamins and minerals that complement agricultural foods. Densities of B. toxisperma, valued for its edible oil, were higher around villages than in concessions. The proportion of commercial trees harvested for timber varied from less than 3% to more than 50%, depending on the species. Different species had different geneflow distances, meaning viable regeneration could be expected with residual adults at different maximum distances. E. cylindricum had more effective dispersal than E. suaveolens. The production of timber and nontimber products can be sustained from the same concessions, for different stakeholders, with appropriate practices and arrangements

    Quantum cascade laser intracavity absorption spectrometer for trace gas sensing

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    A mid-infrared intracavity laser absorption spectrometer for trace gas sensing is demonstrated. An external-cavity multi-mode quantum cascade laser with central wavelength 8.0 mu m was combined with a scanning Fabry-Perot interferometer, which analyzed the change of the laser emission spectrum caused by introducing an analyte inside the cavity. The detection mechanism is based on monitoring the laser spectrum dynamics at adiabatically changing laser conditions in long pulse operation mode. Fast acquisition and vapor exchange allow nearly real-time analyte detection. Sensitivity at the level of 1 x 10(-5) cm(-1) was demonstrated based on a weak water vapor absorption line

    Modelling Land Use Changes in the Republic of Congo 2000-2030 . A report by the REDD-PAC project.

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    This study is intended to assist institutions involved in REDD+ and the planning of National Strategies and Action plans for Biodiversity in the Republic of Congo by attempting to identify the areas under the greatest conversion pressures in the future and the consequences in terms of agricultural production, greenhouse gas emissions and biodiversity loss.Cette Ă©tude essaye d’identifier les zones soumises aux pressions de conversion les plus fortes dans le futur et les consĂ©quences en termes de production agricole, d’émissions de gaz Ă  effet de serre et de risque de perte de biodiversitĂ©. L’objectif du projet REDD-PAC est d’accompagner les institutions impliquĂ©es dans la REDD+ ainsi que dans la planification de la StratĂ©gie Nationale et du Plan d’Action pour la BiodiversitĂ© en RĂ©publique du Congo

    Patent Human Infections with the Whipworm, Trichuris trichiura, Are Not Associated with Alterations in the Faecal Microbiota

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    Background: The soil-transmitted helminth (STH), Trichuris trichiura colonises the human large intestine where it may modify inflammatory responses, an effect possibly mediated through alterations in the intestinal microbiota. We hypothesised that patent T. trichiura infections would be associated with altered faecal microbiota and that anthelmintic treatment would induce a microbiota resembling more closely that observed in uninfected individuals. Materials and Methods: School children in Ecuador were screened for STH infections and allocated to 3 groups: uninfected, T. trichiura only, and mixed infections with T. trichiura and Ascaris lumbricoides. A sample of uninfected children and those with T. trichiura infections only were given anthelmintic treatment. Bacterial community profiles in faecal samples were studied by 454 pyrosequencing of 16 S rRNA genes. Results: Microbiota analyses of faeces were done for 97 children: 30 were uninfected, 17 were infected with T. trichiura, and 50 with T. trichiura and A. lumbricoides. Post-treatment samples were analyzed for 14 children initially infected with T. trichiura alone and for 21 uninfected children. Treatment resulted in 100% cure of STH infections. Comparisons of the microbiota at different taxonomic levels showed no statistically significant differences in composition between uninfected children and those with T. trichiura infections. We observed a decreased proportional abundance of a few bacterial genera from the Clostridia class of Firmicutes and a reduced bacterial diversity among children with mixed infections compared to the other two groups, indicating a possible specific effect of A. lumbricoides infection. Anthelmintic treatment of children with T. trichiura did not alter faecal microbiota composition. Discussion: Our data indicate that patent human infections with T. trichiura may have no effect on faecal microbiota but that A. lumbricoides colonisation might be associated with a disturbed microbiota. Our results also catalogue the microbiota of rural Ecuadorians and indicate differences with individuals from more urban industrialised societies

    Safeguarding villagers’ access to foods from timber trees: Insights for policy from an inhabited logging concession in Gabon

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    This study assessed the abundance of and access to tree species (Ozigo, Dacryodes buettneri; and Abam, Gambeya lacourtiana) that yield edible fruits to villagers and timber to the logging industry in and around a logging concession in Gabon. Participatory mapping combining GPS coordinates and interviews was carried out with 5 female and 5 male collectors in each of two villages within or adjacent to the logging concession. Precommercial and harvestable (>70 cm dbh) Ozigo and Abam trees, as well as their stumps, were also quantified on 20 five ha plots in the 2012 cutting area of the concession and on 21 five ha plots on 10 km transects from each village. Distances to 59 Abam and 75 Ozigo from which fruits were collected ranged from 0.7 to 4.46 Km from the village centres. Most collections were by mixed groups made up of men, women and children (54%) at an average of 1.21 ± 0.09 km; or by men and women (18%) at 2.21 ± 0.15 km; or women and children (14%) at 4.03 ± 0.22 km from the village. Almost 28% of all of the collection trees were inside the logging concession boundaries but outside the village agricultural zone, 43% were inside the village agricultural zone, and 29% were outside the logging concession. Only 33% of Ozigo collection trees had reached commercial size while 75% of Abam trees had. No stumps were found on any sample plots, probably reflecting the ban on felling Ozigo which was in effect at the time; and the relatively low commercial value of Abam. Densities of precommercial Ozigo trees in the cutting area were more than double their densities around the villages (236.0 ± 20.3100 ha−1and 96.6 ± 17.2100 ha−1, respectively), while densities of harvestable Ozigo trees were 7 times higher in the cutting area than around villages (120 ± 20.2100 ha−1and 17.1 ± 3.4100 ha−1respectively). This probably reflects past and current anthropogenic pressures around the villages, including logging and land clearance for agricultural fields. Densities of precommercial Abam were almost four times higher around the village (22.3 ± 5.6 and 6.0 ± 2.9) than on the cutting area. Villagers did not record a decline in availability of or access to these fruits over the past 5 years, suggesting little or no immediate conflict between timber production and access to fruits from these trees
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