988 resultados para distribuzioni temperate, trasformata di Fourier


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Proton NMR spectra of 1,3-diazanaphthalene and 1,2,4-triazanaphthalene have been investigated in the nematic phase of three liquid crystals. The spectral analysis provided direct dipole-dipole couplings which have been used to derive the molecular structure. Geometry of the phenyl ring in both the molecules deviates from the regular hexagonal structure. Signs of the order parameter of the largest magnitude are opposite in liquid crystals with positive diamagetic anisotropies.

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Current-potential relationships are derived for small-amplitude periodic inputs for linear electrochemical systems using a Fourier synthesis procedure. Specific results have been obtained for a triangular potential waveform for two simple model systems.

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Tutkielman aiheena on ekfrasis Gabriele D'Annunzion romaanissa Il Piacere (1889). Lähtökohtana on selvittää, millaisissa muodoissa ekfrasis esiintyy romaanissa sekä miten ekfrasis vaikuttaa teoksen tulkintatradition esille tuomaan tematiikkaan. Pyrkimyksenä on myös selkeyttää ekfrasiksen käsitettä, jonka ongelmana ovat sanaan eri aikakausina liitetyt eri merkitykset. Tärkeimpiä lähdeteoksia ovat James A.W. Heffernanin Museum of Words (1993) ja W.J.T. Mitchellin Picture Theory (1994), Marinella Cantelmon Il Piacere dei leggitori: D'Annunzio e la comunicazione letteraria (1996) sekä John Hollanderin artikkeli "The Poetics of Ekphrasis" (1988). Tutkielman avainkäsitteenä on Heffernanin määritelmä, jonka mukaan ekfrasis on sanallinen esitys kuvallisesta esityksestä. Määritelmää sovellettaessa on otettu huomioon representaatiokäsityksen avautuminen, jolloin vastaanottaja, ympäristö etc. ovat osa esitystä. Korpuksen muodostavat tapahtumaympäristöä, taideteoksia, esineistöä ja henkilöhahmoja kuvaavat ekfrastiset katkelmat. Luokittelussa toimivat alakäsitteinä Valerie Robillardin kuvaileva, attributiivinen ja assosiatiivinen ekfrasis sekä Tamar Yacobin ekfrastinen vertaus. Analyysi osoittaa, että kuvaileva ekfrasis on yleisin, mutta vain kuvitteellisten teosten yhteydessä. Katkelmissa on näkyvissä ekfrasikselle luonteenomainen kerronnallinen impulssi. Ekfrasis osallistuu tunnetun ja uuden elementin vuoropuheluun ankkuroimalla kuvitteelliset taideteokset lukijalle tuttuun ympäristöön, jolloin myös uusi tulee toden kaltaiseksi. Attributiivinen ekfrasis takaa välittömän tunnistettavuuden. Henkilöhahmot, erityisesti keskeiset naishahmot, on määritelty ekfrastisten vertausten kautta. Ekfrasis ilmentää osaltaan naishahmojen vaihdettavuuden tematiikkaa. Kyseessä on myös toiseuden haltuunotto. Kuvallisen viittaussuhteen ansiosta ekfrasis toimii tehokeinona. Tekstuaalisena strategiana ekfrasis luo siteitä tapahtumien välille ja rytmittää teoksen vaiheita. Ekfrastiset katkelmat tarjoavat myös väylän vaihtoehtoiselle tulkinnalle haastamalla tekstin totuuskäsityksen. Kuvallinen ja sanallinen esitys tuovat tekstiin omat merkityksensä, jolloin merkityskenttä laajenee. Il Piacere on intertekstuaalinen kollaasi, jossa kokonaiskuva muodostuu eri elementtien vuorovaikutuksesta. D'Annunzion mielestä kauneus on taiteen ensisijainen tarkoitus, ja ekfrasis retorisena keinona on osa pyrkimystä tavoittaa täydellinen muoto.

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Binuclear complexes of rhodium(I) of the type [(dien)(X)Rh(μ-N-N)Rh(X)(dien)] (dien = 1,5-cyclooctadiene or norbornadiene; N-N = pyrazine, 4,4′-bipyridine or Phenazine and X = Cl or Br) with bridging heterocycles have been isolated and their reactions with carbon monoxide, 2,2′-bipyridine and 1,10-phenanthroline investigated. The crystal structure of [(COD)(Cl)Rh(μ-pyrazine)Rh(Cl)(COD)] has been determined.

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Ultraviolet irradiation of crystalline molecular inclusion complexes of deoxycholic acid with di-tert-butyl thioketone results in no reaction. The structure of the above complex has been determined via X-ray diffraction. The absence of expected photoreactions. namely, photoreduction and photooxidation, is rationalized on the basis of the X-ray structure analysis of the complex.

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Asia's increasing demand for both tropical and temperate fruit is projected to grow significantly. Compared with most developed countries, the production of temperate fruits (peach, nectarine, plum and apple) has expanded rapidly in China over the past 20 years. In contrast, current production of plums and peaches in neighbouring countries (Thailand and Vietnam) is very low but their fruit enters the market earlier. Thailand and Vietnam have enormous potential to satisfy a market window in the northern hemisphere period from March to May inclusive when there is little or no stone fruit on the Asian market. In Vietnam, fruit is harvested in an immature state to avoid disease and fruit fly problems and consequently lacks size and flavour. Approximately 30-40% of locally produced fruit in Vietnam does not reach market due to disease and poor handling during picking and transport. In Thailand, much of the infrastructure needed to transport, store, process and market temperate fruits successfully are now in place. However, there are currently no cool chain management or quality assurance systems to ensure a fresh product reaches the consumer with minimal deterioration. In Vietnam, growing stone fruit under the traditional system with little or minimal inputs, the farmer may receive between AUD3,000-5,000 per ha. In comparison, under higher input systems incorporating fertiliser, irrigation and pest and disease management, net returns can be increased seven-fold. Strengths and weaknesses of the current supply chains in these two countries are discussed.

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The repeat unit of the K12 capsular polysaccharide isolated from the Acinetobacter baumannii global clone 1 clinical isolate, D36, was elucidated by means of chemical and spectroscopical methods. The structure was shown to contain N-acetyl-D-galactosamine (D-GalpNAc), N-acetyl-D-fucosamine and N-acetyl-L-fucosamine linked together in the main chain, with the novel sugar, 5,7-diacetamido-3,5,7,9-tetradeoxy-L-glycero-L-altro-non-2-ulosonic acid (5,7-di-N-acetylacinetaminic acid or Aci5Ac7Ac), attached to D-GalpNAc as a side branch. This matched the sugar composition of the K12 capsule and the genetic content of the KL12 capsule gene cluster reported previously. D-FucpNAc was predicted to be the substrate for the initiating transferase, ItrB3, with the Wzy polymerase making a α-D-FucpNAc-(1 → 3)-D-GalpNAc linkage between the repeat units. The three glycosyltransferases encoded by KL12 are all retaining glycosyltransferases and were predicted to form specific linkages between the sugars in the K12 repeat unit.

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In the subtropics of Australia, irrigated temperate species are the key to reliable cool season feed on dairy farms. Persistence of perennial species is a major limitation to achieving reliable production from irrigated areas and yearly sowings of annual ryegrasses have replaced them as the most productive cool season forage production system in the subtropics. This series of experiments evaluated the yield, and resistance to rust damage, of commercially available cultivars and breeders' lines of annually sown ryegrasses (Lolium multiflorum, L. rigidum, L. x boucheanum and L perenne) in pure, nitrogen-fertilised swards under irrigation in the subtropics over a 22-year period. Barberia and Aristocrat 2 were the most adapted cultivars for subtropical conditions, producing high yields (119 and 114% of mean yield, respectively) and demonstrating the least rust damage. Newer selections from New Zealand, South African, United States of America and European breeding programs are performing better under subtropical conditions than older cultivars, particularly if a component of the selection process has been conducted in that environment. Cultivars such as Passerei Plus, Crusader, Hulk, Status and Warrior are examples of this process, producing between 105 and 115% of mean yield. Yields of annual ryegrass cultivars, which have been available or still are available for sale in Australia, ranged from 14-30 t/ha DM, depending on cultivar, site and seasonal conditions. Yields were lower at the site, which had inferior soil structure and drainage. Up to 50% of yield was produced in the 3 winter months. There was a trend towards improved yields and better tolerance of crown rust from experimental lines in the subtropics, as breeders strive for wider adaptation. Around 70% of the variation in total yield of annual ryegrass and 50 and 60% of the variation in winter and spring yield, respectively, were significantly explained by cultivar, site and climatic variables in autumn, winter and spring. While level of rust damage had no effect on total or seasonal yields, it affected the amount of green leaf available in spring. Under subtropical conditions, winter, spring and overall (autumn to mid-summer) temperatures influenced the- development of rust, which along with cultivar, accounted for 46% of the variation in rust damage. Cultivars showed a range of adaptation, with some performing well only under adverse conditions, some being well adapted to all conditions and some which performed well only under favoured conditions. Cultivars with high winter yields were most suited to subtropical conditions and included Aristocrat 2 (now released as CM 108), Barberia, Warrior, Crusader, Status, Passerei Plus and Hulk. Short growing season types such as Winter Star and T Rex performed well in winter but achieved lower total production, and long season cultivars such as Flanker rarely achieved their potential because of unfavourable conditions in late summer.

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Single layered transition metal dichalcogenides have attracted tremendous research interest due to their structural phase diversities. By using a global optimization approach, we have discovered a new phase of transition metal dichalcogenides (labelled as T′′), which is confirmed to be energetically, dynamically and kinetically stable by our first-principles calculations. The new T′′ MoS2 phase exhibits an intrinsic quantum spin Hall (QSH) effect with a nontrivial gap as large as 0.42 eV, suggesting that a two-dimensional (2D) topological insulator can be achieved at room temperature. Most interestingly, there is a topological phase transition simply driven by a small tensile strain of up to 2%. Furthermore, all the known MX2 (M = Mo or W; X = S, Se or Te) monolayers in the new T′′ phase unambiguously display similar band topologies and strain controlled topological phase transitions. Our findings greatly enrich the 2D families of transition metal dichalcogenides and offer a feasible way to control the electronic states of 2D topological insulators for the fabrication of high-speed spintronics devices.

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Temperate species and tropical crop silage are the basis for forage production for the dairy industry in the Australian subtropics. Irrigation is the key resource needed for production, with little survival of temperate species under rain-grown conditions except for lucerne. Annual ryegrass (Lolium multiflorum), fertilised with either inorganic nitrogen or grown with clovers, is the main cool season forage for the dairy industry. It is sown into fully prepared seedbeds, oversown into tropical grasses, especially kikuyu (Pennisetum clandestinum) or sown after mulching. There has been a continual improvement in the performance of annual and hybrid ryegrass cultivars over the last 25 years. In small plot, cutting experiments, yields of annual ryegrass typically range from 15 to 21 t DM/ha, with equivalent on-farm yields of 7 to 14 t DM/ha of utilised material. Rust (Puccinia coronata) remains the major concern although resistance is more stable than in oats. There have also been major improvements in the performance of perennial ryegrass (L. perenne) cultivars although their persistence under grazing is insufficient to make them a reliable forage source for the subtropics. On the other hand, tall fescue (Festuca arundinacea) and prairie grass (Bromus willdenowii) cultivars perform well under cutting and grazing, although farmer resistance to the use of tall fescue is strong. White clover (Trifolium repens) is a reliable and persistent performer although disease usually reduces its performance in the third year after sowing. Persian (Shaftal) annual clover (T. resupinatum) gives good winter production but the performance of berseem clover (T. alexandrinum) is less reliable and the sub clovers (T. subterraneum) are generally not suited to clay soils of neutral to alkaline pH. Lucerne (Medicago sativa), either as a pure stand or in mixtures, is a high producing legume under both irrigation and natural rainfall. Understanding the importance of leaf and crown diseases, and the development of resistant cultivars, have been the reasons for its reliability. Insects on temperate species are not as serious a problem in the subtropics as in New Zealand (NZ). Fungal and viral diseases, on the other hand, cause many problems and forage performance would benefit from more research into resistance.

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Abstaract is not available.

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The electronic absorption and i.r. spectroscopic studies are reported for the hydrogen bonding systems involving alcohol and various ketones. It is shown that the hydrogen bonding abilities of ketones are determined by the extent of delocalization of the lone pair electrons in their non-bonding molecular orbitals. Evidence for the formation of very weak intermolecular hydrogen bonds between alcohol and the π-electron part of the dicarbonyls has also been presented from the i.r. studies in the 3400–3700 cm−1 region.