964 resultados para planetary rings


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Nekoite Ca3Si6O15•7H2O and okenite Ca10Si18O46•18H2O are both hydrated calcium silicates found respectively in contact metamorphosed limestone and in association with zeolites from the alteration of basalts. The minerals form two-Dimensional infinite sheets with other than six-membered rings with 3-, 4-, or 5-membered rings and 8-membered rings. The two minerals have been characterised by Raman, near-infrared and infrared spectroscopy. The Raman spectrum of nekoite is characterised by two sharp peaks at 1061 and 1092 cm-1 with bands of lesser intensity at 974, 994, 1023 and 1132 cm-1. The Raman spectrum of okenite shows an intense single Raman band at 1090 cm-1 with a shoulder band at 1075 cm-1.These bands are assigned to the SiO stretching vibrations of Si2O5 units. Raman water stretching bands of nekoite are observed at 3071, 3380, 3502 and 3567 cm-1. Raman spectrum of okenite shows water stretching bands at 3029, 3284, 3417, 3531 and 3607 cm-1. NIR spectra of the two minerals are subtly different inferring water with different hydrogen bond strengths. By using a Libowitzky empirical formula, hydrogen bond distances based upon these OH stretching vibrations. Two types of hydrogen bonds are distinguished: strong hydrogen bonds associated with structural water and weaker hydrogen bonds assigned to space filling water molecules.

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Proteasomes are cylindrical particles made up of a stack of four heptameric rings. In animal cells the outer rings are made up of 7 different types of alpha subunits and the inner rings are composed of 7 out of 10 possible different beta subunits. Regulatory complexes can bind to the ends of the cylinder.We have investigated aspects of the assembly, activity and subunit composition of core proteasome particles and 26S proteasomes, the localization of proteasome subpopulations, and the possible role of phosphorylation in determining proteasome localization, activities and association with regulatory components.

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The proteasome (multicatalytic proteinase complex) is a large multimeric complex which is found in the nucleus and cytoplasm of eukaryotic cells. It plays a major role in both ubiquitin-dependent and ubiquitin-independent nonlysosomal pathways of protein degradation. Proteasome subunits are encoded by members of the same gene family and can be divided into two groups based on their similarity to the c~ and /3 subunits of the simpler proteasome isolated from Thermoplasma acidophilum. Proteasomes have a cylindrical structure composed of four rings of seven subunits. The 26S form of the proteasome, which is responsible for ubiquitin-dependent proteolysis, contains additional regulatory complexes. Eukaryotic proteasomes have multiple catalytic activities which are catalysed at distinct sites. Since proteasomes are unrelated to other known proteases, there are no clues as to which are the catalytic components from sequence alignments. It has been assumed from studies with yeast mutants that /3-type subunits play a catalytic role. Using a radiolabelled peptidyl chloromethane inhibitor of rat liver proteasomes we have directly identified RC7 as a catalytic component. Interestingly, mutants in Prel, the yeast homologue of RC7, have already been reported to have defective chymotrypsin-like activity. These results taken together confirm a direct catalytic role for these/3-type subunits. Proteasome activities are sensitive to conformational changes and there are several ways in which proteasome function may be modulated in vivo. Our recent studies have shown that in animal cells at least two proteasome subunits can undergo phosphorylation, the level of which is likely to be important for determining proteasome localization, activity or ability to form larger complexes. In addition, we have isolated two isoforms of the 26S proteinase.

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This article places the 6 June 2012 transit of Venus in the context of James Cook’s voyage from England to the South Pacific to observe the 1769 transit of Venus. A description is given on how to use a computer program called Stellarium to ‘observe’ the 1769 transit of Venus exactly as Cook saw it from the island of Tahiti in the South Pacific.

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In the structure of the title salt 2C7H10N+.C8H2Cl2O4(2-) .H2O the two benzylaminium anions have different conformations, one being essentially planar the other having the side-chain rotated out of the benzene plane (minimum ring to side-chain C-C-C-N torsion angles = -3.6(6) and 50.1(5)\%, respectively). In the 4,5-dichlorophthalate dianion the carboxyl groups make ihedral angles of 23.0(2) and 76.5(2)\% with the benzene ring. Aminium N-H...O and water O-H...O hydrogen-bonding associations with carboxyl O-atom acceptors give a two-dimensional duplex sheet structure which extends along the (011) plane. Weak pi-pi interactions are also present between the benzene ring and one of the cation rings [minimum ring centroid separation = 3.749(3)Ang.

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In the structure of the title compound C14H9Cl3I2, which is the p-iodophenyl analogue of the insecticide DDT [1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane], isomorphism between the two compounds has been confirmed. In the molecule the dihedral angle between the planes of the two phenyl rings is 65.8(4)deg. which compares with 64.7(7)deg. in DDT.

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Ecological sustainability has been proposed to address the problem of human impacts increasingly degrading planetary resources and ecosystems, threatening biodiversity, eco-services and human survival. Ecological sustainability is an imperative, with Australia having one of the highest eco-footprints per person worldwide. While significant progress has been made via implementation of ecologically sustainable design in urban communities, relatively little has been undertaken in small, disparate regional communities in Australia. Regional communities are disadvantaged by rural economic decline associated with structural change and inequities of resource transfer. The ecologically sustainable solution is holistic, so all settlements need to be globally wise, richly biodiverse yet locally specific. As a regional solution to this global problem, this research offers the practical means by which a small regional community can contribute. It focuses on the design and implementation of a community centre and the fostering of transformative community learning through an integrated ‘learning community’ awareness of ecologically sustainable best practice. Lessons learned are documented by the participant researcher who as a designer, facilitator, local resident and social narrator has been deeply connected with the Tweed-Caldera region over a period since 1980. The collective action of the local community of Chillingham has been diligently recorded over a decade of design and development. Over this period, several positive elements emerged in terms of improvements to the natural and built environment, greater social cohesion and co-operative learning along with a shift towards a greener local economy. Behavioural changes in the community were noted as residents strived to embrace ecological ideals and reduce fossil fuel dependency. They found attractive local solutions to sourcing of food and using local employment opportunities to up skill their residents via transformative learning as a community in transition. Finally, the catalytic impact of external partnering has also been documented. How well the region as a whole has achieved its ecologically sustainable objectives is measured in terms of the delivered success of private and public partnering with the community, the creation of a community centre cum environment education centre, the restoration of local heritage buildings, the repair of riparian forests and improved water conditions in local river systems, better roads and road safety, local skills and knowledge transfer, support of local food and local/regional growers markets to attract tourists via the integrated trails network. In aggregate, each and every element contributes to a measure of eco-positive development for the built environment, its social organisation and its economy that has guided the local community to find its own pathway to sustainability. Within the Tweed-Caldera bioregion in northern New South Wales, there has been a lack of strategic planning, ecologically sustainable knowledge and facilities in isolated communities that could support the development of a local sustained green economy, provide a hub for socio-cultural activities and ecology based education. The first challenge in this research was to model a whole systems approach to eco-positive development in Chillingham, NSW, a small community where Nature and humanity know no specific boundary. The net result was the creation of a community environment education centre featuring best-affordable ecological practice and regionally distinctive, educational building form from a disused heritage building (cow bale). This development, implemented over a decade, resonated with the later regional wide programs that were linked in the Caldera region by the common purpose of extending the reach of local and state government assistance to regional NSW in economic transition coupled with sustainability. The lessons learned from these linked projects reveal that subsequent programs have been significantly easier to initiate, manage, develop and deliver results. In particular, pursuing collaborative networks with all levels of government and external private partners has been economically effective. Each community’s uniqueness has been celebrated and through drawing out these distinctions, has highlighted local vision, strategic planning, sense of belonging and connection of people with place. This step has significantly reduced the level of friction between communities that comes from natural competition for the finite pool of funds. Following the pilot Tweed-Caldera study, several other NSW regional communities are now undertaking a Community Economic Transition Program based on the processes, trials and positive experiences witnessed in the Tweed-Caldera region where it has been demonstrated that regional community transition programs can provide an opportunity to plan and implement effective long term strategies for sustainability, empowering communities to participate in eco-governance. This thesis includes the design and development of a framework for community created environment education centres to provide an equal access place for community to participate to meet their essential needs locally. An environment centre that facilitates community transition based on easily accessible environmental education, skills and infrastructure is necessary to develop local cultures of sustainability. This research draws upon the literatures of ecologically sustainable development, environmental education and community development in the context of regional community transition towards ‘strong sustainability’. The research approach adapted is best described as a four stage collaborative action research cycle where the participant researcher (me) has a significant involvement in the process to foster local cultures of sustainability by empowering its citizens to act locally and in doing so, become more self reliant and socially resilient. This research also draws upon the many fine working exemplars, such as the resilience of the Cuban people, the transition town initiative in Totnes, U.K. and the models of Australian Community Gardens, such as CERES (Melbourne) and Northey Street (Brisbane). The objectives of this study are to research and evaluate exemplars of ecologically sustainable environment education centres, to facilitate the design and development of an environment education centre created by a small regional community as an ecologically sustainable learning environment; to facilitate a framework for community transition based on environmental education, skills and infrastructure necessary to develop local cultures of sustainability. The research was undertaken as action research in the Tweed Caldera in Northern NSW. This involved the author as participant researcher, designer and volunteer in two interconnected initiatives: the Chillingham Community Centre development and the Caldera Economic Transition Program (CETP). Both initiatives involved a series of design-led participatory community workshops that were externally facilitated with the support of government agency partnerships, steering committees and local volunteers. Together the Caldera research programs involved communities participating in developing their own strategic planning process and outcomes. The Chillingham Community Centre was developed as a sustainable community centre/hub using a participatory design process. The Caldera Economic Transition Program (CETP) prioritised Caldera region projects: the Caldera farmer’s market; community gardens and community kitchens; community renewable energy systems and an integrated trails network. The significant findings were: the CETP projects were capable of moving towards an eco-positive design benchmark through transformative learning. Community transition to sustainability programs need to be underpinned by sustainability and environmental education based frameworks and practical on ground experience in local needs based projects through transformative learning. The actioned projects were successfully undertaken through community participation and teamwork. Ecological footprint surveys were undertaken to guide and assess the ongoing community transition process, however the paucity of responses needs to be revisited. The concept of ecologically sustainable development has been adopted internationally, however existing design and planning strategies do not assure future generations continued access to healthy natural life support systems. Sustainable design research has usually been urban focussed, with little attention paid to regional communities. This study seeks to redress this paucity through the design of ecologically sustainable (deep green) learning environments for small regional communities. Through a design-led process of environmental education, this study investigates how regional communities can be facilitated to model the principles of eco-positive development to support transition to local cultures of sustainability. This research shows how community transition processes and projects can incorporate sustainable community development as transformative learning through design. Regional community transition programs can provide an opportunity to plan long term strategies for sustainability, empowering people to participate in eco-governance. A framework is developed for a community created environment education centre to provide an equal access place for the local community to participate in implementing ways to meet their essential needs locally. A community environment education centre that facilitates community transition based on holistic environmental education, skills and infrastructure is necessary to develop local cultures of sustainability.

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In the structure of the title compound C22H27Cl302, which is the p-butoxyphenyl analogue of the insecticidally active p-methoxyphenyl compound methoxychlor, the dihedral angle between the two phenyl rings is 79.61(11)deg. Present also in the structure is an intramolecular aromatic C-H...Cl interaction [3.361(2)Ang].

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The structures of the open chain amide carboxylic acid rac-cis-[2-(2-methoxyphenyl)carbamoyl]cyclohexane-1-carboxylic acid, C15H19NO4, (I) and the cyclic imides rac-cis-2-(4-methoxyphenyl)-3a,4,5,6,7,7-hexahydroisoindole-1,3-dione,C15H17NO3, (II), chiral cis-2-(3-carboxyphenyl)-3a,4,5,6,7,7a-hexahydroisoindole-1,3-dione, C15H15NO4,(III) and rac-cis-2-(4-carboxyphenyl)- 3a,4,5,6,7,7a-hexahydroisoindole-1,3-dione monohydrate, C15H15NO4. H2O) (IV), are reported. In the amide acid (I), the phenylcarbamoyl group is essentially planar [maximum deviation from the least-squares plane = 0.060(1)Ang. for the amide O atom], the molecules form discrete centrosymmetric dimers through intermolecular cyclic carboxy-carboxy O-H...O hydrogen-bonding interactions [graph set notation R2/2(8)]. The cyclic imides (II)--(IV) are conformationally similar, with comparable phenyl ring rotations about the imide N-C(aromatic) bond [dihedral angles between the benzene and isoindole rings = 51.55(7)deg. in (II), 59.22(12)deg. in (III) and 51.99(14)deg. in (IV). Unlike (II) in which only weak intermolecular C-H...O(imide) hydrogen bonding is present, the crystal packing of imides (III) and (IV) shows strong intermolecular carboxylic acid O-H...O hydrogen-bonding associations. With (III), these involve imide O-atom acceptors, giving one-dimensional zigzag chains [graph set C(9)], while with the monohydrate (IV), the hydrogen bond involves the partially disordered water molecule which also bridges molecules through both imide and carboxyl O-atom acceptors in a cyclic R4/4(12) association, giving a two-dimensional sheet structure. The structures reported here expand the structural data base for compounds of this series formed from the facile reaction of cis-cyclohexane-1,2-dicarboxylic anhydride with substituted anilines, in which there is a much larger incidence of cyclic imides compared to amide carboxylic acids.

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In the title compound, C18H19Cl3O2, which is the 4-ethoxyphenyl analogue of the insecticidally active 4-methoxyphenyl compound methoxychlor, the dihedral angle between the two benzene rings is 60.38(13)deg. An intramolecular aromatic C-H...Cl interaction is present.

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In the structure of the title compound C17H16Br2O3, which is a restricted commercial acaricide (common name bromopropylate), has two independent and conformationally similar molecules in the asymmetric unit [dihedral angle between the planes of the two phenyl rings in each, 68.7(4) and 77.4(5)deg]. The C-atoms of the isopropyl group of one of the molecules are disordered over two sites with occupancies of 0.638 and 0.362. Minor non-merohedral twinning was also present in the crystal. Intermolecular hydrogen-bonding interactions involving the hydroxy groups and carboxyl O-atom acceptors give separate centrosymmetric homodimers through cyclic hydrogen-bonding motifs [graph set R2/2(10)].

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Purpose: To determine whether there is a difference in neuroretinal function and in macular pigment optical density between persons with high- and low-risk gene variants for age-related macular degeneration (AMD) and no ophthalmoscopic signs of AMD, and to compare the results on neuroretinal function to patients with manifest early AMD. Methods and Participants: Neuroretinal function was assessed with the multifocal electroretinogram (mfERG) for 32 participants (22 healthy persons with no AMD and 10 early AMD patients). The 22 healthy participants with no AMD had high- or low-risk genotypes for either CFH (rs380390) and/or ARMS2 (rs10490924). Trough-to-peak response densities and peak-implicit times were analyzed in 5 concentric rings. Macular pigment optical densitometry was assessed by customized heterochromatic flicker photometry. Results: Trough-to-peak response densities for concentric rings 1 to 3 were, on average, significantly greater in participants with high-risk genotypes than in participants with low-risk genotypes and in persons with early AMD after correction for age and smoking (p<0.05). The group peak- implicit times for ring 1 were, on average, delayed in the patients with early AMD compared with the participants with high- or low-risk genotypes, although these differences were not significant. There was no significant correlation between genotypes and macular pigment optical density. Conclusion: Increased neuroretinal activity in persons who carry high-risk AMD genotypes may be due to genetically determined subclinical inflammatory and/or histological changes in the retina. Neuroretinal function in healthy persons genetically susceptible to AMD may be a useful additional early biomarker (in combination with genetics) before there is clinical manifestation.

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The Sudbury Basin is a non-cylindrical fold basin occupying the central portion of the Sudbury Impact Structure. The impact structure lends itself excellently to explore the structural evolution of continental crust containing a circular region of long-term weakness. In a series of scaled analogue experiments various model crustal configurations were shortened horizontally at a constant rate. In mechanically weakened crust, model basins formed that mimic several first-order structural characteristics of the Sudbury Basin: (1) asymmetric, non-cylindrical folding of the Basin, (2) structures indicating concentric shortening around lateral basin termini and (3) the presence of a zone of strain concentration near the hinge zones of model basins. Geometrically and kinematically this zone corresponds to the South Range Shear Zone of the Sudbury Basin. According to our experiments, this shear zone is a direct mechanical consequence of basin formation, rather than the result of thrusting following folding. Overall, the models highlight the structurally anomalous character of the Sudbury Basin within the Paleoproterozoic Eastern Penokean Orogen. In particular, our models suggest that the Basin formed by pure shear thickening of crust, whereas transpressive deformation prevailed elsewhere in the orogen. The model basin is deformed by thickening and non-cylindrical synformal buckling, while conjugate transpressive shear zones propagated away from its lateral tips. This is consistent with pure shear deformation of a weak circular inclusion in a strong matrix. The models suggest that the Sudbury Basin formed as a consequence of long-term weakening of the upper crust by meteorite impact.