991 resultados para 790
Resumo:
Although subsampling is a common method for describing the composition of large and diverse trawl catches, the accuracy of these techniques is often unknown. We determined the sampling errors generated from estimating the percentage of the total number of species recorded in catches, as well as the abundance of each species, at each increase in the proportion of the sorted catch. We completely partitioned twenty prawn trawl catches from tropical northern Australia into subsamples of about 10 kg each. All subsamples were then sorted, and species numbers recorded. Catch weights ranged from 71 to 445 kg, and the number of fish species in trawls ranged from 60 to 138, and invertebrate species from 18 to 63. Almost 70% of the species recorded in catches were "rare" in subsamples (less than one individual per 10 kg subsample or less than one in every 389 individuals). A matrix was used to show the increase in the total number of species that were recorded in each catch as the percentage of the sorted catch increased. Simulation modelling showed that sorting small subsamples (about 10% of catch weights) identified about 50% of the total number of species caught in a trawl. Larger subsamples (50% of catch weight on average) identified about 80% of the total species caught in a trawl. The accuracy of estimating the abundance of each species also increased with increasing subsample size. For the "rare" species, sampling error was around 80% after sorting 10% of catch weight and was just less than 50% after 40% of catch weight had been sorted. For the "abundant" species (five or more individuals per 10 kg subsample or five or more in every 389 individuals), sampling error was around 25% after sorting 10% of catch weight, but was reduced to around 10% after 40% of catch weight had been sorted.
Resumo:
CsHsN204, M r = 197.2, monoclinic, P21/e , a= 7.818 (2), b= 7.589 (2), e= 14.790 (2)A, t= 98.43 (2) °, V= 868.02/k 3, Z = 4, D m = 1.506 (3), Dx= 1.501Mgm -3, MoKa, 2=0.7107/~, #= 0-79 mm -1, F(000) = 408, T= 426 (1) K, final R = 0.0507 for 798 observed reflections [I_> 2e(/)]. The molecules are hydrogen bonded: N-H...O = 2.886 (3), N--H = 0.97 (7), H--O = 1.92 (6) A, N-- H...O angle = 175.5 (8) °.
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The sciaenid Protonibea diacanthus is a large, long-lived predatory fish of inshore northern Australian waters, which forms annual aggregations that are fished extensively by traditional (subsistence) and recreational fishers. There are now widespread concerns that the resource is being overexploited. Indigenous fishers of the Cape York Northern Peninsula Area (NPA) relate that large adult fish (up to 1500 mm total length (TL)) made up the bulk of the catch from the sciaenid aggregations until about 1994. In contrast, sexually mature P. diacanthus comprised only a small component (12 fish out of 270=4.4%) examined in a 1999–2000 sampling programme that was biased towards the largest individuals available. At 790 mm TL, the minimum size at first maturity for female P. diacanthus in this study is much smaller than the 920 mm TL reported previously in Queensland waters. Developing ovaries were observed in specimens sampled from sciaenid aggregations which formed in NPA waters between May and September 2000. However, no fish with ripe or spent gonads were found in the study, so the current timing and location of the spawning season for P. diacanthus in the region remain unknown. Food items observed in the analysis of the diet of P. diacanthus from the NPA included a variety of teleosts and invertebrates. The range of animal taxa represented in the prey items support the description of an ‘opportunistic predator’ attributed to the species. In our sampling, the stomach contents of fish caught during the time of the aggregation events did not differ from those observed at other times of the year. A total of 114 P. diacanthus were tagged and released at aggregation sites during the study period, and 3 fish (2.6%) were subsequently recaptured. The low rate of tag returns from the wild stock tagging programme, both in this study (2.6%) and from recreational fisher tag/release programmes for the sciaenid elsewhere in Queensland (6.5%), were not explained by tag loss nor mortality, given the high retention rate of tags and the zero mortality seen in tank trials. In response to the biological findings from this study, indigenous community councils of the NPA imposed a 2-year fishing moratorium for P. diacanthus. Surveys at aggregation sites in 2002 and 2003 established that much larger fish (mean size 103.5 cm TL) were again present on the grounds, albeit in very low numbers. These recent preliminary results highlight the critical need for continued monitoring and management of the P. diacanthus fishery in the NPA, if prospects for resource recovery are to be realised. The NPA initiative has provided a rare opportunity to negotiate a co-management strategy, based on scientific data and traditional knowledge, for the recovery of a cultural and economically significant fished resource.
Resumo:
Kymmenkunta vuotta sitten monessa Suomen kunnassa jouduttiin suureen nimeämistyöhön, kun kuntien keskusjärjestöt suosittivat osoitejärjestelmän luomista myös haja-asutusalueille. Kunnille annetut ohjeet käsittelivät lähinnä osoitejärjestelmän teknistä toteuttamista, eikä nimistönsuunnittelun vaativuutta tajuttu. Tärkein asia eli teiden nimeäminen jäi lähes täysin kunnallisten virkamiesten ja poliitikkojen harkinnan varaan. Varsinkin kaksikielisissä kunnissa jouduttiin hankaluuksiin: tiennimet piti luoda kahdella kielellä, vaikka vanha paikannimistö olisi yksikielistä. Tilannetta mutkisti se, että nimistönsuunnittelun suhtautuminen vanhan paikannimistön kääntämiseen ja mukauttamiseen oli murroksessa juuri osoitteistamisprosessin alussa, eikä uusia periaatteita tuotu selvästi julki ennen 1990-luvun puoliväliä. Vielä 1980-luvulla paikannimien kääntämistä ja mukauttamista suositeltiin, mutta nykyään pidetään jo selvänä, että vanhaa paikannimistöä ei pidä perusteetta muokata vaan sitä voidaan käyttää sellaisenaan. Käypiä nimiä ovat siis niin Kråköntie kuin Koivulavägen. Porvoon maalaiskunnassa nimeämistyö aloitettiin vuonna 1989. Hankkeelle määrättiin virkamiesvalmistelija, joka työskenteli yhdessä toimikunnan kanssa. Tiekunnat saivat ehdottaa teilleen nimiä, ja valtaosaehdotuksista otettiinkin huomioon, mutta alkuvaiheessa lähes kaikki ruotsinkieliset paikannimet käännettiin tai mukautettiin. Koska toimikunnan jäsenillä ei ollut asiantuntemusta, nimien käännökset olivat usein epäonnistuneita ja oikeinkirjoitus horjui. Nähtävilläolon jälkeen alkuvuonna 1991 toimikunta päätti turvautua Kotimaisten kielten tutkimuskeskuksen apuun. Tiekunnat eivät hyväksyneet käännöksiä ja mukaelmia, joten ne neuvojen jälkeen poistettiin. Myöhemmin käännökset palautettiin luontonimiin perustuviin tiennimiin, mutta suurimmalta osalta vanha nimistö säilyi muuttamattomana. Emmintöjen jälkeen kunnanhallitus hyväksyi nimistön syksyllä 1995. Suurin osa Porvoon maalaiskunnan 790:stä haja-asutusalueen tiennimestä perustuu vanhaan paikannimistöön (81 %) tai on muuten paikkaan liittyvää (15 %). Vain pieni osa nimistä (4 %) on harkinnaisia.Vanhaan paikannimistöön perustuvissa tiennimissä on eniten tilannimen (41 %), maastonimen (26 %) ja kylännimen (14 %) sisältäviä nimiä. Yleisimmät jälkiosat ovat tie (86 %), kuja (5 %) ja polku (5 %). Määriteosaltaan tyystin suomenkielisiä nimipareista on 14 % (Aholantie-Aholavägen) ja ruotsinkielisiä 36 % (Bodöntie-Bodövägen). Tiekuntien nimet ja uudet tiennimet ovat eri asioita, mutta noin kolmannes uusista tiennimistä sisältää tiekunnan nimessä esiintyvän nimen. Näin Porvoon maalaiskunnan tiekuntien nimissä esiintyvistä 252 määriteosasta 193:a (77 %) on hyödynnetty 245 uudessa tiennimessä. Ennen tiennimiä osoitteissa käytettiin yleensä vain postinumeroa ja postitoimipaikkaa. Jonkin verran käytössä oli myös osoitenimiä (esim. Björkebo, Kappeli). Niistäkin valtaosa (73 %) esiintyy uusissa tiennimissä. Laskelma pohjautuu postin osoitetietojärjestelmään. Uusi tiennimistö perustuu usein jo käytössä oleviin tien- ja paikannimiin, joten se ei uhkaa vanhan nimistön asemaa. Uuden nimistön vaikutusta vähentää sekin, että sitä tarvitsevat lähinnä ulkopuoliset. Kotitienoot hahmotetaan edelleenkin vanhojen ja vakiintuneiden paikannimien avulla, mutta toki uudet tiennimet tuovat esiin monia vähän käytettyjä paikannimiä ja tarjoavat mainion katsauksen seudun kulttuuriperintöön. Ei siis ole samantekevää, miten teitä nimetään. Huonoiksi koetut uudet nimet eivät välttämättä edes vakiinnu käyttöön. Porvoon maalaiskunnan tulosten vertaaminen koko Suomen kattavaan materiaaliin osoittaa hankkeen edenneen hitaasti, mutta kaksikielisyyden ja työvoiman vähyyden huomioon ottaen kohtalaisesti. Vertailu kuuden muun uusmaalaisen kunnan kanssa paljastaa eroja paitsi hankkeen toteuttamistavoissa myös työn tuloksessa eli nimistössä. Yleensä tiekunnat ja asukkaat ovat saaneet tehdä ehdotuksia ja nimistön ovat laatineet virkamiehet ja nimitoimikunnat ilman palkattua asiantuntijaa. Kotimaisten kielten tutkimuskeskuksen puoleen on sentään käännytty. Tärkeä havainto on se, että kaksikieliset kunnat ovat halunneet vaalia kulttuuriarvoja ja säilyttää keskeisen vanhan paikannimistönsä koskemattomana. Avainsanat: Tiennimet, osoitenimet, osoitejärjestelmä, nimistönsuunnittelu
Resumo:
We tested the capacity of several published multispectral indices to estimate the nitrogen nutrition of wheat canopies grown under different levels of water supply and plant density and derived a simple canopy reflectance index that is greatly independent of those factors. Planar domain geometry was used to account for mixed signals from the canopy and soil when the ground cover was low. A nitrogen stress index was developed, which adjusts shoot %N for plant biomass and area, thereby accounting for environmental conditions that affect growth, such as crop water status. The canopy chlorophyll content index (CCCi) and the modified spectral ratio planar index (mSRPi) could explain 68 and 69% of the observed variability in the nitrogen nutrition of the crop as early as Zadoks 33, irrespective of water status or ground cover. The CCCi was derived from the combination of 3 wavebands 670, 720 and 790 nm, and the mSRPi from 445, 705 and 750 nm, together with broader bands in the NIR and RED. The potential for their spatial application over large fields/paddocks is discussed.
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State and parameter estimations of non-linear dynamical systems, based on incomplete and noisy measurements, are considered using Monte Carlo simulations. Given the measurements. the proposed method obtains the marginalized posterior distribution of an appropriately chosen (ideally small) subset of the state vector using a particle filter. Samples (particles) of the marginalized states are then used to construct a family of conditionally linearized system of equations and thus obtain the posterior distribution of the states using a bank of Kalman filters. Discrete process equations for the marginalized states are derived through truncated Ito-Taylor expansions. Increased analyticity and reduced dispersion of weights computed over a smaller sample space of marginalized states are the key features of the filter that help achieve smaller sample variance of the estimates. Numerical illustrations are provided for state/parameter estimations of a Duffing oscillator and a 3-DOF non-linear oscillator. Performance of the filter in parameter estimation is also assessed using measurements obtained through experiments on simple models in the laboratory. Despite an added computational cost, the results verify that the proposed filter generally produces estimates with lower sample variance over the standard sequential importance sampling (SIS) filter.
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Familial typical migraine is a common, complex disorder that shows strong familial aggregation. Using latent-class analysis (LCA), we identified subgroups of people with migraine/severe headache in a community sample of 12,245 Australian twins (60% female), drawn from two cohorts of individuals aged 23-90 years who completed an interview based on International Headache Society criteria. We report results from genomewide linkage analyses involving 756 twin families containing a total of 790 independent sib pairs (130 affected concordant, 324 discordant, and 336 unaffected concordant for LCA-derived migraine). Quantitative-trait linkage analysis produced evidence of significant linkage on chromosome 5q21 and suggestive linkage on chromosomes 8, 10, and 13. In addition, we replicated previously reported typical-migraine susceptibility loci on chromosomes 6p12.2-p21.1 and 1q21-q23, the latter being within 3 cM of the rare autosomal dominant familial hemiplegic migraine gene (ATP1A2), a finding which potentially implicates ATP1A2 in familial typical migraine for the first time. Linkage analyses of individual migraine symptoms for our six most interesting chromosomes provide tantalizing hints of the phenotypic and genetic complexity of migraine. Specifically, the chromosome 1 locus is most associated with phonophobia; the chromosome 5 peak is predominantly associated with pulsating headache; the chromosome 6 locus is associated with activity-prohibiting headache and photophobia; the chromosome 8 locus is associated with nausea/vomiting and moderate/severe headache; the chromosome 10 peak is most associated with phonophobia and photophobia; and the chromosome 13 peak is completely due to association with photophobia. These results will prove to be invaluable in the design and analysis of future linkage and linkage disequilibrium studies of migraine.
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Glyphosate resistance is a rapidly developing threat to profitability in Australian cotton farming. Resistance causes an immediate reduction in the effectiveness of in-crop weed control in glyphosate-resistant transgenic cotton and summer fallows. Although strategies for delaying glyphosate resistance and those for managing resistant populations are qualitatively similar, the longer resistance can be delayed, the longer cotton growers will have choice over which tactics to apply and when to apply them. Effective strategies to avoid, delay, and manage resistance are thus of substantial value. We used a model of glyphosate resistance dynamics to perform simulations of resistance evolution in Sonchus oleraceus (common sowthistle) and Echinochloa colona (awnless barnyard grass) under a range of resistance prevention, delaying, and management strategies. From these simulations, we identified several elements that could contribute to effective glyphosate resistance prevention and management strategies. (i) Controlling glyphosate survivors is the most robust approach to delaying or preventing resistance. High-efficacy, high-frequency survivor control almost doubled the useful lifespan of glyphosate from 13 to 25 years even with glyphosate alone used in summer fallows. (ii) Two non-glyphosate tactics in-crop plus two in-summer fallows is the minimum intervention required for long-term delays in resistance evolution. (iii) Pre-emergence herbicides are important, but should be backed up with non-glyphosate knockdowns and strategic tillage; replacing a late-season, pre-emergence herbicide with inter-row tillage was predicted to delay glyphosate resistance by 4 years in awnless barnyard grass. (iv) Weed species' ecological characteristics, particularly seed bank dynamics, have an impact on the effectiveness of resistance strategies; S. oleraceus, because of its propensity to emerge year-round, was less exposed to selection with glyphosate than E. colona, resulting in an extra 5 years of glyphosate usefulness (18 v. 13 years) even in the most rapid cases of resistance evolution. Delaying tactics are thus available that can provide some or many years of continued glyphosate efficacy. If glyphosate-resistant cotton cropping is to remain profitable in Australian farming systems in the long-term, however, growers must adapt to the probability that they will have to deal with summer weeds that are no longer susceptible to glyphosate. Robust resistance management systems will need to include a diversity of weed control options, used appropriately.
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Microwave treated water soluble and amide functionalized single walled carbon nanotubes have been investigated using femtosecond degenerate pump-probe and nonlinear transmission experiments. The time resolved differential transmission using 75 femtosecond pulse with the central wavelength of 790 nm shows a bi-exponential ultrafast photo-bleaching with time constants of 160 fs (130 fs) and 920 fs (300 fs) for water soluble (amide functionalized) nanotubes. Open and closed aperture z-scans show saturation absorption and positive (negative) nonlinear refraction for water soluble (amide functionalized) nanotubes. Two photon absorption coefficient, beta(0) similar to 250 cm/GW (650 cm/GW) and nonlinear index, gamma similar to 15 cm(2)/pW (-30 cm(2)/pW) are obtained from the theoretical fit in the saturation limit to the data for two types of nanotubes.
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The conformation of the synthetic cyclic tetrapeptide cyclo(D-Phe-Pro-Sar-Gly) has been determined in solution using the nuclear magnetic resonance technique and in the crystal state by X-ray crystallography. Results showed that the peptide exhibited two different conformations in solution, conformer 1 having cis-trans-cis-trans peptide bonds and conformer 2 having trans-cis-trans-cis peptide bonds. No intramolecular hydrogen bonds were observed in the structures. The X-ray diffraction studies showed the crystals to be orthorhombic with space group P2(1)2(1)2(1) with unit-cell dimensions, a = 5.790, b = 10.344, c = 31.446 A, Z = 4, R = 0.104 for 2301 observed reflections. The crystal structure showed only one type of conformer having cis-trans-cis-trans peptide bonds similar to the conformer 1 in solution.
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Purpose - The purpose of this paper is to apply lattice Boltzmann equation method (LBM) with multiple relaxation time (MRT) model, to investigate lid-driven flow in a three-dimensional (3D), rectangular cavity, and compare the results with flow in an equivalent two-dimensional (2D) cavity. Design/methodology/approach - The second-order MRT model is implemented in a 3D LBM code. The flow structure in cavities of different aspect ratios (0.25-4) and Reynolds numbers (0.01-1000) is investigated. The LBM simulation results are compared with those from numerical solution of Navier-Stokes (NS) equations and with available experimental data. Findings - The 3D simulations demonstrate that 2D models may predict the flow structure reasonably well at low Reynolds numbers, but significant differences with experimental data appear at high Reynolds numbers. Such discrepancy between 2D and 3D results are attributed to the effect of boundary layers near the side-walls in transverse direction (in 3D), due to which the vorticity in the core-region is weakened in general. Secondly, owing to the vortex stretching effect present in 3D flow, the vorticity in the transverse plane intensifies whereas that in the lateral plane decays, with increase in Reynolds number. However, on the symmetry-plane, the flow structure variation with respect to cavity aspect ratio is found to be qualitatively consistent with results of 2D simulations. Secondary flow vortices whose axis is in the direction of the lid-motion are observed; these are weak at low. Reynolds numbers, but become quite strong at high Reynolds numbers. Originality/value - The findings will be useful in the study of variety of enclosed fluid flows.
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Nonlinear optical properties and carrier relaxation dynamics in graphene, suspended in three different solvents, are investigated using femtosecond (80 fs pulses) Z-scan and degenerate pump-probe spectroscopy at 790 nm. The results demonstrate saturable absorption property of graphene with a nonlinear absorption coefficient, beta of (similar to 2-9) x 10(-8) cm/W. Two distinct time scales associated with the relaxation of photoexcited carriers, a fast one in the range of 130-330 fs (related to carrier-carrier scattering) followed by it slower one in 3.5-4.9 ps range (associated with carrier-phonon scattering) are observed. (C) 2009 American Institute of Physics.
Resumo:
Experiments are carried out with air as the test gas to obtain the surface convective heating rate on a missile shaped body flying at hypersonic speeds. The effect of fins on the surface heating rates of missile frustum is also investigated. The tests are performed in a hypersonic shock tunnel at stagnation enthalpy of 2 MJ/kg and zero degree angle of attack. The experiments are conducted at flow Mach number of 5.75 and 8 with an effective test time of 1 ms. The measured stagnation-point heat-transfer data compares well with the theoretical value estimated using Fay and Riddell expression. The measured heat-transfer rate with fin configuration is slightly higher than that of model without fin. The normalized values of experimentally measured heat transfer rate and Stanton number compare well with the numerically estimated results. (C) 2009 Elsevier Inc. All rights reserved.