961 resultados para exotic weeds
Resumo:
Cotoneaster pannosus (Rosaceae), an ornamental shrub native to China, is reported for the first time in Tarragona Province (Catalonia, Spain). Data on demography and accompanying species for the new locality are provided, in addition to a chrorological update at nation level.
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As a continuation of previous research on the naturalization of non-native vascular plants in the Iberian Peninsula new chorological data are presented for 16 xenophytes recorded between 2010 and 2014, mostly in the provinces of Huelva and Barcelona (Spain) and in the Algarve and Estremadura (Portugal). For each taxon details about distribution, habitats occupied, previous records, degree of naturalization, etc. are provided. Lachenalia bulbifera and Cyperus albostriatus are probably reported for the first time in the wild in Europe, as are Gamochaeta filaginea, and Dysphania anthelmintica and Oenothera lindheimeri for Portugal and Spain respectively. Cosmos bipinnatus is cited as a novelty for the Algarve (Portugal). Newly reported or confirmed for the province of Huelva are: Amaranthus hypochondriacus, Epilobium brachycarpum, Nephrolepis cordifolia, Ficus microcarpa, Tamarix parviflora and Tamarix ramosissima, while Atriplex semibaccata, Chloris truncata, and Elymus elongatus subsp. ponticus are new for Barcelona. Finally, Passiflora caerulea is a novelty for both Barcelona and Huelva provinces.
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At the end of 1773 an Indian elephant, brought for the royal ménagerie at Aranjuez, was shown in the streets of Madrid. The resulting public fascination provoked by the intrusion of this exotic animal can be traced through poems (Tomás de Iriarte), short plays (Ramón de la Cruz), articles in the periodical press, popular and scientific prints representing the animal, and even in the costumbrista pastels of Lorenzo Tiepolo. The mythic and premodern knowledge of animal nature collides in a debate with the new scientific observation. In the final decades of the 18th century, the image of the captive elephant acquired in Europe a new symbolic meaning linked with the political fight against slavery. All these very different elements converge in Goya's Disparate de bestia.
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Muldoon’s poetry frequently explores states of being ‘in-between’ and this can plausibly be related to his Catholic Northern Irish identity. He seems to be aware of the effects comprised in Derrida’s concept of différance, one version of which is the entre (‘between’). Nevertheless, Muldoon is more interested in exploring the experience of postmodernity than in offering a theory, or relating it to one culture. But this exploration has as many similarities with the concerns of existentialism and phenomenology as with deconstruction. Poems from Why Brownlee Left to Moy Sand and Gravel are discussed, and topics addressed include the South American exotic (new sources are suggested) and the troping on yarrow (compare Derrida’s pharmakon) in The Annals of Chile. Formal effects of repetition and difference reflect the themes. The redemption of repetition is studied with the help both of Kierkegaard and of Muldoon’s thoughts on the ‘magic mist’ of Irish romance.
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By engineering the internal structure of artificial materials it is possible to reproduce effective electromagnetic properties, including some which were previously unavailable in nature. Since the first experimental demonstration of artificial composites with exotic electromagnetic properties at microwaves less than 10 years ago, metamaterials has emerged as a rapidly growing multidisciplinary branch of science and engineering. Significant efforts have been placed in scaling the response of metamaterials to optical frequencies as well as demonstrate pertinent applications of the newly available technology. In this article we review recent developments in the area of experimental realisation of electromagnetic metamaterials and their applications.
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By use of high intensity XUV radiation from the FLASH free-electron laser at DESY, we have created highly excited exotic states of matter in solid-density aluminum samples. The XUV intensity is sufficiently high to excite an inner-shell electron from a large fraction of the atoms in the focal region. We show that soft-x-ray emission spectroscopy measurements reveal the electronic temperature and density of this highly excited system immediately after the excitation pulse, with detailed calculations of the electronic structure, based on finite-temperature density functional theory, in good agreement with the experimental results.
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Saturable absorption is a phenomenon readily seen in the optical and infrared wavelengths. It has never been observed in core-electron transitions owing to the short lifetime of the excited states involved and the high intensities of the soft X-rays needed. We report saturable absorption of an L-shell transition in aluminium using record intensities over 10(16)W cm(-2) at a photon energy of 92 eV. From a consideration of the relevant timescales, we infer that immediately after the X-rays have passed, the sample is in an exotic state where all of the aluminium atoms have an L-shell hole, and the valence band has approximately a 9 eV temperature, whereas the atoms are still on their crystallographic positions. Subsequently, Auger decay heats the material to the warm dense matter regime, at around 25 eV temperatures. The method is an ideal candidate to study homogeneous warm dense matter, highly relevant to planetary science, astrophysics and inertial confinement fusion.
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Aims. Massive stars in low-metallicity environments may produce exotic explosions such as long-duration gamma-ray bursts and pair-instability supernovae when they die as core-collapse supernovae (CCSNe). Such events are predicted to be relatively common in the early Universe during the first episodes of star-formation. To understand these distant explosions it is vital to study nearby CCSNe arising in low-metallicity environments to determine if the explosions have different characteristics to those studied locally in high-metallicity galaxies. Many of the nearby supernova searches concentrate their efforts on high star-formation rate galaxies, hence biasing the discoveries to metal rich regimes. Here we determine the feasibility of searching for these CCSNe in metal-poor dwarf galaxies using various survey strategies.
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This paper presents significant new insights into the appearance of agriculture at the north- western edge of Europe, focusing on Neolithic Ireland (4000-2500 cal BC). Previous studies were based upon a limited plant macro-remains dataset, as much of the Irish evidence is unpublished. A research project, 'Cultivating Societies', was implemented to examine the nature, timing and extent of agricultural activity in Neolithic Ireland through collation and analysis of different strands of published and unpublished archaeological and environmental evidence, with a particular focus on plant macro- remains, pollen, settlement and 14C data. Plant macro-remains from a total of 52 excavated sites were collated and analysed, representing the most comprehensive study to date of Neolithic plant remains from this region. Cereals were present at many locations and site types, sometimes in large quantities and most often at sites dating to the earlier Neolithic (3750-3600 cal BC). Emmer wheat was the dominant crop, at least at this time. Other crops included naked and hulled barley, naked wheat, einkorn wheat and flax. Analysis of arable weeds indicates that early plots were not managed under a shifting cultivation regime, which has important implications for understanding Neolithic settlement practices and how communities engaged with landscapes. The variety of crops cultivated in Neolithic Ireland is similar to those in Britain, reflecting a decreasing diversity in crop types as agriculture spread from south-east to north-west Europe.
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This article examines the soundscapes of Ariane Mnouchkine’s Tambours Sur La Digue and explores the concept of acoustic mimesis located in the performance as a dramaturgical strategy to create, aurally, an imagined Far East. In Tambours, mimesis is the performative principle exemplified by the presentation of the mise en scène, and most distinctly Mnouckine’s decision to adapt the Japanese performance tradition of Bunraku through a process of 'reversed' mimicry (in which human bodies simulate the wooden marionettes of the Japanese style). Mimesis pervades the acoustemologies of the performance as it is heard in the extracted sounds, styles, and rhythms of Asian musical modes and movements that consequently become dislocated from context; the sounds become imitated, iconicised and exoticised as sonic signatures as they reify the Orientalist spectacle. The 'oriental' soundscape, reverberating with exotic overtones, becomes the means by which the production creates an imaginary Orient – one in which the Orient Other is silenced, and is resounded only through the musical sensibilities of the Occidental Self.
Resumo:
Pollen tube growth is dependent on a dynamic actin cytoskeleton, suggesting that actin-regulating proteins are involved. We have examined the regulation of the lily pollen-specific actin-depolymerizing factor (ADF) LIADF1. Its actin binding and depolymerizing activity is pH sensitive, inhibited by certain phosphoinositides, but not controlled by phosphorylation. Compared with its F-actin binding properties, its low activity in depolymerization assays has been used to explain why pollen ADF decorates F-actin in pollen grains. This low activity is incompatible with a role in increasing actin dynamics necessary to promote pollen tube growth. We have identified a plant homolog of actin-interacting protein, AIP1, which enhances the depolymerization of F-actin in the presence of LIADF1 by similar to60%. Both pollen ADF and pollen AIP1 bind F-actin in pollen grains but are mainly cytoplasmic in pollen tubes. Our results suggest that together these proteins remodel actin filaments as pollen grains enter and exit dormancy.
Resumo:
We have examined the interaction of recombinant lily pollen ADF, LIADF1, with actin and found that whilst it bound both G- and F-actin, it had a much smaller effect on the polymerization and depolymerization rate constants than the maize vegetative ADF, ZmADF3. An antiserum specific to pollen ADF, antipADF, was raised and used to localize pollen ADF in daffodil - a plant in which massive reorganizations of the actin cytoskeleton have been seen to occur as pollen enters and exits dormancy. We show, for the first time, an ADF decorating F-actin in cells that did not result from artificial increase in ADF concentration. In dehydrated pollen this ADF:actin array is replaced by actin:ADF rodlets and aggregates of actin, which presumably act as a storage form of actin during dormancy. In germinated pollen ADF has no specific localization, except when an adhesion is made at the tip where actin and ADF now co-localize. These activities of pollen ADF are discussed with reference to the activities of ZmADF3 and other members of the ADF/cofilin group of proteins.
Resumo:
Maize actin-depolymerizing factor, ZmADF, binds both G- and F-actin and enhances in vitro actin dynamics. Evidence from studies on vertebrate ADF/cofilin supports the view that this class of protein responds to intracellular and extracellular signals and causes actin reorganization. As a test to determine whether such signal-responsive pathways existed in plants, this study addressed the ability of maize ADF to be phosphorylated and the likely effects of such phosphorylation on its capacity to modulate actin dynamics. It is shown that maize ADF3 (ZmADF3) can be phosphorylated by a calcium-stimulated protein kinase present in a 40-70% ammonium sulphate fraction of a plant cell extract. Phosphorylation is shown to be on Ser6, which is only one of nine amino acids that are fully conserved among the ADF/cofilin proteins across distantly related species. In addition, an analogue of phosphorylated ZmADF3 created by mutating Ser6 to Asp6 (zmadf3-4) does not bind G- or F-actin and has little effect on the enhancement of actin dynamics. These results are discussed in context of the previously observed actin reorganization in root hair cells.
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Superficially, electrostatic potential profiles of supersolitons look like those of traditional solitons. However, their electric field profiles are markedly different, having additional extrema on the wings of the standard bipolar structure. This new concept was recently pointed out in the literature for a plasma model with five species. Here, it is shown that electrostatic supersolitons are not an artefact of exotic, complicated plasma models, but can exist even in three-species plasmas and are likely to occur in space plasmas. Further, a methodology is given to delineate their existence domains in a systematic fashion by determining the specific limiting factors. © 2013 American Institute of Physics.