3,155 research outputs found
Assessment of decadal-scale ecological change at a deep Mid-Atlantic hydrothermal vent and reproductive time-series in the shrimp Rimicaris exoculata
No full textThis study presents a comparison of distribution and abundance of dominant megafaunal species at the TAG hydrothermal mound on the Mid-Atlantic Ridge from 1994 to 2004. A Geographical Information System (GIS) database was compiled from georeferenced observations of faunal abundances at 534 locations on the TAG hydrothermal mound, determined by image analysis of ROV dive footage from November 2004. These data are compared with observations from submersible dives in 1994 to assess changes in the extent and population density of aggregations of the shrimp Rimicaris exoculata at the central black smokers of TAG. The GIS database was also used to assess changes in abundance and distribution of the anemone Maractis rimicarivora by simulating the path of a biotransect conducted in 1994 and 1995. There was no evidence of a decline in the extent of shrimp aggregations at the central black smokers of TAG between 1994 and 2004. This result indicates that occasional exposure to high-intensity submersible lighting, which took place during several scientific expeditions in the intervening period, does not pose an immediate conservation threat to populations of R. exoculata. Similarly, there were no significant differences in the distribution and abundance of anemones between 1994 and 2004. These results indicate a constancy in the identity, distribution and abundance of dominant species at TAG that contrasts with other vent sites where quantitative time-series have been established. The reproductive pattern of R. exoculata was also examined by dissection and direct measurement of oocytes from females collected in September 1994 and November 2004, providing the first comparison of reproductive development in samples from different months for this species. There was no significant difference in oocyte size-frequency distributions of females collected in these samples, indicating a lack of seasonal reproduction in R. exoculata
The response of borehole water levels in an ophiolitic, peridotite aquifer to atmospheric, solid Earth, and ocean tides
No full textPeridotite aquifers are ubiquitous on Earth, but most are in the deep-sea, and thus difficult to access. Ophiolites provide a unique opportunity to study peridotite aquifers, and the Oman Drilling Project established a Multi-Borehole Observatory in a peridotite terrain of the Samail ophiolite. We use the water level response of two 400-m deep boreholes (BA1B, BA1D) to solid Earth, ocean, and atmospheric tides to investigate the hydromechanical structure of the aquifer. The two boreholes are offset by ∼ 100 m but exhibit markedly different tidal responses, indicating a high degree of short-length-scale heterogeneity. Hole BA1B does not respond to tidal strain or barometric loading, consistent with the behavior of an unconfined aquifer. Hole BA1D responds to both tidal strain and barometric loading, indicating some degree of confinement. The response to applied strain, which includes a non-negligible ocean tidal loading component, is consistent with a partially confined, low conductivity aquifer. The response to barometric loading appears to be affected by the complex hydrological structure of the surficial zone and we were not able to fit the observations to within error. Aquifer conductivity estimates for Hole BA1D based on the response to tidal strain are within a factor of ∼ 3 of pumping test estimates
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No full textHere is a curious book. Its title-page declares "The Artist's Book of Fables" but its pre-title-page has "Fables, Original and Selected, with a Memoir of the Author." After that title-page, it is identical with "Fables, Original and Selected" as in our copy printed by John Murray in 1833. There is again an AI at the front and an index of engravings and engravers at the back. I found that copy twenty years ago. I had found an inferior copy twenty-two years before that. At that time, I noted Aesopic fables here including "Stone Broth" and "The Mouse and the Oyster."This is a hardbound book (hard cover)James Northcote, R.A
Gas Migration Episodes Observed During Peridotite Alteration in the Samail Ophiolite, Oman
No full textSerpentinization and carbonation of mantle rocks (peridotite alteration) are fundamentally important processes for a spectrum of geoscience topics, including arc volcanism, earthquake processes, chemosynthetic biological communities, and carbon sequestration. Data from a hydrophone array deployed in the Multi‐Borehole Observatory (MBO) of the Oman Drilling Project demonstrates that free gas generated by peridotite alteration and/or microbial activity migrates through the formation in discrete bursts of activity. We detected several, minutes‐long, swarms of gas discharge into Hole BA1B of the MBO over the course of a 9 month observation interval. The episodic nature of the migration events indicates that free gas accumulates in the permeable flow network, is pressurized, and discharges rapidly into the borehole when a critical pressure, likely associated with a capillary barrier at a flow constriction, is reached. Our observations reveal a dynamic mode of fluid migration during serpentinization, and highlight the important role that free gas can play in modulating pore pressure, fluid flow, and alteration kinetics during peridotite weathering
Turbulent entrainment in a shearless mixing layer at the edge of a cloud
No full textThree-dimensional direct numerical simulations which combine the Eulerian description of temperature, vapor content and velocity with a Lagrangian ensemble of cloud water droplets are used to study the turbulent entrainment and subsequent mixing of clear air with a cloudy air filament. The study is conducted in a shearless mixing layer setup which is adjusted to realistic conditions at a cumulus cloud boundary. The magnitude of turbulent velocity fluctuations in- and outside the cloud can be varied independently. We find that the evolution of the cloud water droplet ensemble depends slightly only on the contrast of turbulent velocity fluctuations in- and outside the cloud filament. The buoyancy feedback on the flow via the evaporating droplets causes a transient amplification of all fluctuations before the turbulence eventually decays. We study the evolution of the probability density functions of droplet size as well as of supersaturation, temperature and vorticity at the droplet positions
Flyleaf of The Village Politicians, signed by author and publisher R.A. Parsons, and printed by Guardian Ltd.
No full textNewIntroduction. Flyleaf of the The Village Politicans by R.A. Parsons and printed by Guardian Ltd.DA vol. 15 no.
Non-Linear Time Series Analysis of Deep Groundwater Levels: An application to the Veluwe
No full textThe objective of this study is to improve the simulation of deep groundwater levels by time se- ries models with pre-defined impulse response functions. This is attempted by adding a conceptual non-linear root zone model to simulate the recharge series to the model and by testing the use of a separate response function for the percolation zone. Three root zone models are developed based on two different recharge mechanisms: preferential flow, percolation, and a combination of the two. The performance of these models is compared to a linear model that is commonly used in time se- ries models to simulate the recharge. The approach is applied to groundwater level measurements in the Veluwe, a largely forested area in the Netherlands characterized by thick unsaturated zones. The effect of groundwater extractions and land reclamations is added to the model to further im- prove the simulation of the groundwater levels. The models are tested on three observations wells with increasing thickness of the unsaturated zone, varying from 7 m to 29 m to 49 m. The results show that model performance is improved by the implementation of a non-linear root zone model, particularly in simulating the peaks and lows in the groundwater levels. The recharge fluxes simulated by the non-linear models show different patterns that are physically more realistic than those simulated by the linear model. It is shown that different recharge series result in simulated groundwater levels that are very similar. This is a clear example of equifinality and it is recommended to introduce new sources of information to validate the modelled processes (e.g., water content measurements of the percolation zone or actual evaporation data). For the shallow well, the models with a single response function are selected as the best. The largest improvements for the deeper groundwater levels are obtained by the addition of a separate response for the percolation zone. For example, the average deviation from the observed ground- water levels decreased 0.18 m to 0.08 m for the deepest observation well by applying the separate response function. The models with an additional response function were better at simulating the estimated time to peak, the time it takes a recharge pulse to cause a peak in the groundwater levels. The time to peak is introduced in this research as a qualitative indicator to validate the modelled processes. The simulated responses indicate that the groundwater levels respond very quickly to water that leaves the root zone, even though the percolation zone is tens of metres thick. For each of the observations wells it is investigated if adding the effect of groundwater extrac- tions or land reclamations of Flevoland to the models improves the simulation of the groundwater levels. For the shallow well it is concluded that either the effect of land reclamations or groundwater extractions needs to be taken into account. Since these two stresses are correlated, it is concluded that only one of these should be taken into account when no further information is available to con- strain the models. For the medium deep well, the additional stresses did not significantly improve model performance and it is concluded that they do not have to be taken into account for this well. For the deep well, model performance is improved by both stresses. The largest improvements are observed when the effect of groundwater extractions is considered in the model. For implemen- tation of these stresses, the entire simulation period should be used for calibration, or constraints have to be implemented to obtain realistic results.Water ResourcesWater ManagementCivil Engineering and Geoscience
Chemicals from renewable biomass: A renaissance in carbohydrate chemistry
No full textThe conversion of sugars, derived from waste polysaccharide biomass, to commodity chemicals by fermentation or catalytic hydrogenation, oxidation or dehydration or combinations thereof are reviewed.Accepted Author ManuscriptBT/Biocatalysi
A Chemoenzymatic Synthesis Of The Sex Pheromone Of Lasioderma Serricorne F
No full textA short and efficient preparation of enantiomerically enriched (80% ee) (-)-serricornine (1), the sex pheromone of the cigarette beetle Lasioderma serricorne F., was developed in 8 steps and 13% overall yield from methyl (R)-3-hydroxypentanoate readily prepared by baker's yeast reduction of methyl 3-oxopentanoate in the presence of allyl alcohol as enzyme inhibitor.96571576Mori, K., (1989) Tetrahedron, 45, p. 3233Mori, K., (1994) Pure and Appl. Chem., 66, p. 1991Servi, S., (1990) Synthesis, p. 1Csuk, K., Glänzer, B.I., (1991) Chem. Rev., 91, p. 49Santaniello, E., Ferraboschi, P., Grisenti, P., Manzocchi, A., (1992) Chem. Rev., 92, p. 1071Nakamura, K., Higaki, M., Ushio, K., Oka, S., Ohno, A., (1985) Tetrahedron Lett., 26, p. 4213Nakamura, K., Kawai, Y., Oka, S., Ohno, A., (1989) Tetrahedron Lett., 30, p. 2245Buisson, C., Sanner, M., Larcheveque, R., Azerad, R., (1987) Tetrahedron Lett., 28, p. 3939Nakamura, K., Inoue, K., Ushio, K., Oka, S., Ohno, A., (1987) Chem. Lett., p. 679Nakamura, K., Kawai, Y., Ohno, A., (1990) Tetrahedron Lett., 31, p. 267Nakamura, K., Kawai, Y., Nakajima, N., Ohno, A., (1991) J. Org. Chem., 56, p. 4778Fràter, G., Müller, U., Günther, W., (1984) Tetrahedron, 40, p. 1269Mori, K., Watanabe, H., (1985) Tetrahedron, 41, p. 3423Pereira, R.S., Parizotto, N.A., Baranauskas, V., (1996) Appl. Biochem. Biotech., 59, p. 135Pilli, R.A., Murta, M.M., (1993) J. Org. Chem., 58, p. 338Pilli, R.A., Andrade, C.K.Z., (1994) Synth. Commun., 24, p. 1994Heathcock, C.H., Pirrung, M.C., Sohn, J., (1979) J.Org. Chem., 44, p. 4294Mitsunobu, O., (1981) Synthesis, p. 1Redlich, H., Samm, K., Lenfers, J.G., Bruns, W., (1988) Carbohydrate Res., 174, p. 341Mori, M., Chuman, T., Kato, K., (1984) Tetrahedron Lett., 25, p. 2553Shimizu, I., Hayashi, K., Ide, N., Oshima, M., (1991) Tetrahedron, 47, p. 2991Mori, K., Nomi, H., Chuman, T., Kohno, M., Kato, K., Noguchi, M., (1982) Tetrahedron, 38, p. 370
KONSEP HARKAT DAN MARTABAT PEREMPUAN DALAM BUKU HABIS GELAP TERBITLAH TERANG KARYA R.A KARTINI DAN RELEVANSINYA TERHADAP PENDIDIKAN ISLAM
No full textThe background of this research originated from the admiration of the author of the book Habis Gelap Terbitlah Terang by R.A. Kartini who has an extraordinary spirit in fighting for the dignity of women. Women who are not valued, are not recognized, and do no have the opportunity to develop themselves during the R.A. Kartini, now has freedom. His dignity and recognition are recognized by the community. But along with the development of the era that was so extraordinary. Book Habis Gelap Terbitlah Terang began to be forgotten by the people. This research included qualitative research and the type of research that the authors do is library research. The research approach used is the historical approach. The method of data collection in this study is adjusted to the type of research conducted, namely the research library, then the right data collection method is the collection and documentation method. Data analysis in this study uses content analysis method. Based on the results of research conducted by the author about the concept of the dignity of women in view of R.A. Kartini can be concluded that the concept of the dignity of women in the view of R.A. Kartini has seven concepts: educated women, virtuous women, skilled women, free women who are civilized and educated, men collaborate with women, women who are knowledgeable about religion, and delete the caste system in society. The seven concepts have a close relationship to Islamic education which is focused on the goal of Islamic education, namely facilitates women to develop themselves, both in the realm of individuals, families, social and in work so that we create human being.Latar belakang penelitian ini berawal dari kekaguman penulis pada buku Habis Gelap Terbitlah Terang karya R.A. Kartini yang memiliki semangat luar biasa dalam memperjuangkan harkat dan martabat perempuan. Perempuan yang tidak dihargai, tidak diakui, dan tidak memiliki kesempatan untuk mengembangkan diri pada masa R.A. Kartini, kini telah memiliki kebebasan. Harkat dan martabatnya terakui oleh masyarakat. Namun seiring perkembangan zaman yang begitu luar biasa. Buku Habis Gelap Terbitlah Terang ini mulai terlupakan oleh masyarakat. Penelitian ini termasuk penelitian kualitatif dan jenis penelitian yang penulis lakukan merupakan penelitian kepustakaan (library research). Pendekatan penelitian yang digunakan yaitu pendekatan sejarah (histori). Metode pengumpulan data dalam penelitian ini disesuaikan dengen jenis penelitian yang dilakukan, yaitu library research maka metode pengumpulan data yang tepat adalah metode pengumpulan dan dokumentasi. Analisis data pada penelitian ini menggunakan metode content analysis. Berdasarkan hasil penelitian yang dilakukan oleh penulis tentang konsep harkat dan martabat perempuan dalam pandangan R.A. Kartini dapat disimpulkan bahwa konsep harkat dan martabat perempuan dalam pandangan R.A. Kartini ada tujuh konsep yaitu: perempuan berpendidikan, perempuan berbudi luhur, perempuan berketerampilan, perempuan bebas yang beradab dan terpelajar, laki-laki bekerjasama dengan perempuan, perempuan yang berpengetahuan ilmu agama, serta menghapus sistem kasta di masyarakat. Ketujuh konsep tersebut memiliki hubungan yang erat terhadap pendidikan Islam yang difokuskan pada tujuan pendidikan Islam yaitu memfasilitasi perempuan untuk mengembangkan diri, baik dalam ranah individu, keluarga, sosial dan dalam berkarya sehingga terciptalah insan kamil
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