887 resultados para non-native macrophytes


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The microbiological responses of two bivalves species from Tagus estuary, Venerupis pullastra (native clam) and Ruditapes philippinarum (exotic clam) were investigated during 48h of depuration and subsequent simulated transport in semi-dry conditions at two temperatures (4 and 22°C) until reaching 50% lethal time (LT50). Regardless of temperature and species, the maintenance of clams in water for 48h (depuration period) did not affect LT50 during transport. R.philippinarum showed higher survival rates than V.pullastra, always reaching LT50 later, especially at 4°C. Significant differences between clams' species were found in almost all microbiological parameters. This can be related with clams' biological activity and habitat environmental conditions since both clams do not coexist in Tagus estuary. Depuration was efficient to reduce the bacterial load, particularly Escherichia coli, but not efficient to remove Vibrio spp. In both species, the growth of Vibrio spp. was inhibited at 4°C, whereas exponential growth occurred at 22°C. Total viable counts significantly increased in most treatments, while E.coli counts significantly decreased to undetected levels, except for non-depurated R.philippinarum simulated transported at 4°C. Thus, this study highlights the importance of clams depuration for at least 24h in polluted estuarine areas, followed by transport at low temperatures (4°C). © 2013 Elsevier Ltd.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The present study sought to develop and validate an interview version of the Native American Cultural Involvement and Detachment Anxiety Questionnaire (CIDAQ; McNeil, Porter, Zvolensky, Chaney, & Kee, 2000) in an effort to construct a more culturally appropriate means of obtaining anxiety-related information from a tribally homogenous sample of Native Americans. Five pilot subjects (60% women; M age = 35.8 years) and 50 Native American participants (46% women; M age = 40.32 years) residing on a Northern Plains reservation were administered the CIDAQ - Interview, designed specifically for this study, the Worry Domains Questionnaire (WDQ; Tallis, Eysenck, & Mathews, 1992), a measure of non-pathological worry, the CIDAQ (McNeil et al., 2000), a self-report measure of culturally-related anxiety, and a demographics form. Using a mixed design method of analysis, interviews were audio taped and data was both qualitatively and quantitatively compared for convergence and discrepancies across measures. As hypothesized, CIDAQ-Interview subscales corresponded with subscales from the CIDAQ self-report and included worries and anxiety in three content areas: (1) social involvement with Native Americans and cultural knowledge, (2) economic issues, and (3) social involvement with the majority culture. Results further revealed similarities between CIDAQ-Interview items and those on the CIDAQ self-report, indicating reliability for the Interview. Findings also confirmed the Interview's validity (r 's range = .349-.754), as well as a high level of internal consistency for the CIDAQ self-report (Cronbach alpha = .931). Data suggest the CIDAQ-Interview is a more culturally appropriate method of assessment and may be capable of assessing anxiety at a higher level of specificity then the self-report version. Results of the study are discussed in relation to the assessment of anxiety for homogenous reservation Native Americans, study limitations and directions for future research with the CIDAQ-Interview are also discussed.

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Black carbon (BC) is an important fraction of many soils worldwide and plays an important role in global C biogeochemistry. However, few studies have examined how it influences the mineralization of added organic matter (AOM) and its incorporation into soil physical fractions and whether BC decomposition is increased by AOM. BC-rich Anthrosols and BC-poor adjacent soils from the Central Amazon (Brazil) were incubated for 532 days either with or without addition of (13)C-isotopically different plant residue. Total C mineralization from the BC-rich Anthrosols with AOM was 25.5% (P < 0.05) lower than with mineralization from the BC-poor adjacent soils. The AOM contributed to a significantly (P < 0.05) higher proportion to the total C mineralized in the BC-rich Anthrosols (91-92%) than the BC-poor adjacent soils (69-80%). The AOM was incorporated more rapidly in BC-rich than BC-poor soils from the separated free light fraction through the intra-aggregate light fraction into the stable organo-mineral fraction and up to 340% more AOM was found in the organo-mineral fraction. This more rapid stabilization was observed despite a significantly (P < 0.05) lower metabolic quotient for BC-rich Anthrosols. The microbial biomass (MB) was up to 125% greater (P < 0.05) in BC-rich Anthrosols than BC-poor adjacent soils. To account for increased MB adsorption onto BC during fumigation extraction, a correction factor was developed via addition of a (13)C-enriched microbial culture. The recovery was found to be 21-41 % lower (P < 0.05) for BC-rich than BC-poor soils due to re-adsorption of MB onto BC. Mineralization of native soil C was enhanced to a significantly greater degree in BC-poor adjacent soils compared to BC-rich Anthrosols as a result of AOM. No positive priming by way of cometabolism due to AOM could be found for aged BC in the soils. (C) 2009 Elsevier Ltd. All rights reserved.

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Invasive species are potential threats to biodiversity, especially if they become established and outnumber native species. In this study, a population of the non-indigenous crab Charybdis hellerii was analyzed in an estuary-bay complex on the southeastern Brazilian coast, with respect to its abundance relative to sympatric native brachyuran species, as well as the size structure, sexual maturity, sex ratio, frequency of mutilation, reproductive period, and development of the reproductive system. Crabs were sampled monthly both in the intertidal zone of rocky shores and on sublittoral soft-bottom. Nine species were recorded on the rocky shores, where C. hellerii was the second most abundant species; only three individuals of C. hellerii were collected in the sublittoral samples. This population of C. hellerii showed a unimodal size structure composed mainly of mature individuals; males were larger than females, and the sex ratio was skewed toward males (3.1:1). About 46.9% of the individuals (75 of 160 crabs) had mutilated or regenerating appendages, more frequent in males (56.8%) than in females (28.2%), which may reflect both inter- and intraspecific agonistic interactions. A continuous reproductive pattern is suggested for this population, although ovigerous females occurred unevenly during the year, with 58.82% of them being collected in winter. There was evidence of multiple spawning, since the ovigerous females with an initial egg mass showed mature ovaries as well as seminal receptacles filled with sperm. C. hellerii is well established in the estuary-bay complex, but is concentrated in intertidal and shallow subtidal rocky shores, where it may compete with and replace other species such as the portunid Cronius ruber. This study also highlights the importance of systematic monitoring studies to evaluate the effects of the introduction of non-indigenous species on ecologically similar natives.

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The area covered by Eucalyptus plantations is significantly increasing in Brazil for economic reasons. However, the impact of such land use change is still unknown. In this study we evaluated the spatial-temporal distribution and abundance of terrestrial non-volant small mammals on a recently converted landscape whose matrix is formed by Eucalyptus plantations up to 3 years of age. From August 2007 to July 2009 we carried out monthly sampling campaigns over a grid of 30 sampling units, formed by pitfall traps covering both the landscape matrix of Eucalyptus plantations (n = 18) and legal conservation areas of native vegetation (n = 7) and abandoned pastures (n = 5). A total of 1640 individuals from 14 species of the orders Didelphimorphia (4 spp.) and Rodentia (10 spp.) were captured. However, only three species of rodents (Olygorysomys flavescens, Oligoryzomys nigripes and Calomy tener) represented 81.8% of the total amount. Eucalyptus plantations had a lower species richness and abundance than the abandoned pasture and the remaining fragments of native vegetation. Although the present species are predominantly generalists, there is clear distinction among environments in terms of their species composition and relative abundance, which also present a pronounced time variation. The assemblage found in this study suggests that silvicultural landscapes still have some conservation value, with species that seem to be resident at the Eucalyptus plantations. Moreover, the presence of the native and abandoned pastures patches imbibed in the Eucalyptus plantation matrix may increase the carrying capacity of such a silvicultural system and these landscapes may play a role in maintaining local biodiversity. (C) 2012 Elsevier B.V. All rights reserved.

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Negli ultimi anni il mondo del mobile computing ha avuto una vera e propria crescita esponenziale grazie soprattutto all'entrata in scena dello smartphone. In realtà, per essere più precisi, è bene bene sottolineare che gli smartphone esistevano già da tempo ma il loro utilizzo era in particolar modo indirizzato ai professionisti per il quale era, ma continua ad essere tutt'oggi, un valido supporto in campo lavorativo, basti pensare all'importanza della comunicazione via e-mail e non solo. Seppur comunque fossero già presenti da tempo, i primi smartphone non godevano di certo di un touch-screen sofisticato come quello odierno nè in essi erano presenti funzionalità tipiche dei dispositivi che troviamo ad oggi sul mercato. Una svolta decisiva è stata segnata dall'introduzione dell'iPhone e successivamente dell'AppStore, grazie a questi la programmazione per i dispositivi mobile ha preso sempre più piede diventando un vero e proprio business. In un secondo momento alla programmazione nativa si affiancarono le tecnologie web. Questo mio lavoro di tesi si pone l'obiettivo di studiare in primis la struttura, caratteristiche e peculiarità del sistema operativo iOS e analizzare il framework PhoneGap al fine di riuscire a confrontarne i vari aspetti fondamentali anche attraverso lo sviluppo di piccole applicazioni. Così facendo, quindi scendendo nei dettagli di quelle che possono essere le differenze rilevanti, mi pongo l'obiettivo di valutarne relativi pro e contro al fine di fare una scelta del tutto personale tra iOS e PhoneGap.

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BACKGROUND: Coronary stents improve immediate and late results of balloon angioplasty by tacking up dissections and preventing wall recoil. These goals are achieved within weeks after angioplasty, but with current technology stents permanently remain in the artery, with many limitations including the need for long-term antiplatelet treatment to avoid thrombosis. We report a prospective multicentre clinical trial of coronary implantations of absorbable magnesium stents. METHODS: We enrolled 63 patients (44 men; mean age 61.3 [SD 9.5 years]) in eight centres with single de novo lesions in a native coronary artery in a multicentre, non-randomised prospective study. Follow-up included coronary angiography and intravascular ultrasound at 4 months and clinical assessment at 6 months and 12 months. The primary endpoint was cardiac death, non-fatal myocardial infarction, or clinically driven target lesion revascularisation at 4 months FINDINGS: 71 stents, 10-15 mm in length and 3.0-3.5 mm in diameter, were successfully implanted after pre-dilatation in 63 patients. Diameter stenosis was reduced from 61.5 (SD 13.1%) to 12.6 (5.6%) with an acute gain of 1.41 mm (0.46 mm) and in-stent late loss of 1.08 mm (0.49 mm). The ischaemia-driven target lesion revascularisation rate was 23.8% after 4 months, and the overall target lesion revascularisation rate was 45% after 1 year. No myocardial infarction, subacute or late thrombosis, or death occurred. Angiography at 4 months showed an increased diameter stenosis of 48.4 (17.0%). After serial intravascular ultrasound examinations, only small remnants of the original struts were visible, well embedded into the intima. Neointimal growth and negative remodelling were the main operating mechanisms of restenosis. INTERPRETATION: This study shows that biodegradable magnesium stents can achieve an immediate angiographic result similar to the result of other metal stents and can be safely degraded after 4 months. Modifications of stent characteristics with prolonged degradation and drug elution are currently in development.

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Ecological disturbances may be caused by a range of biotic and abiotic factors. Among these are disturbances that result from human activities such as the introduction of exotic plants and land management activities. This dissertation addresses both of these types of disturbance in ecosystems in the Upper Peninsula of Michigan. Invasive plants are a significant cause of disturbance at Pictured Rocks Natural Lakeshore. Management of invasive plants is dependent on understanding what areas are at risk of being invaded, what the consequences of an invasion are on native plant communities and how effective different tools are for managing the invasive species. A series of risk models are described that predict three stages of invasion (introduction, establishment and spread) for eight invasive plant species at Pictured Rocks National Lakeshore. These models are specific to this location and include species for which models have not previously been produced. The models were tested by collecting point data throughout the park to demonstrate their effectiveness for future detection of invasive plants in the park. Work to describe the impacts and management of invasive plants focused on spotted knapweed in the sensitive Grand Sable Dunes area of Pictured Rocks National Lakeshore. Impacts of spotted knapweed were assessed by comparing vegetation communities in areas with varying amounts of spotted knapweed. This work showed significant increases in species diversity in areas invaded by knapweed, apparently as a result of the presence of a number of non-dune species that have become established in spotted knapweed invaded areas. An experiment was carried out to compare annual spot application of two herbicides, Milestone® and Transline® to target spotted knapweed. This included an assessment of impacts of this type of treatment on non-target species. There was no difference in the effectiveness of the two herbicides, and both significantly reduced the density of spotted knapweed during the course of the study. Areas treated with herbicide developed a higher percent cover of grasses during the study, and suffered limited negative impacts on some sensitive dune species such as beach pea and dune stitchwort, and on some other non-dune species such as hawkweed. The use of these herbicides to reduce the density of spotted knapweed appears to be feasible over large scales.

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Adaptive and non-adaptive evolutionary processes are likely to play important roles in biological invasions but their relative importance has hardly ever been quantified. Moreover, although genetic differences between populations in their native versus invasive ranges may simply reflect different positions along a genetic latitudinal cline, this has rarely been controlled for. To study non-adaptive evolutionary processes in invasion of Mimulus guttatus, we used allozyme analyses on offspring of seven native populations from western North America, and three and four invasive populations from Scotland and New Zealand, respectively. To study quantitative genetic differentiation, we grew 2474 plants representing 17 native populations and the seven invasive populations in a common greenhouse environment under temporarily and permanently wet soil conditions. The absence of allozyme differentiation between the invasive and native range indicates that multiple genotypes had been introduced to Scotland and New Zealand, and suggests that founder effects and genetic drift played small, if any, roles in shaping genetic structure of invasive M. guttatus populations. Plants from the invasive and native range did not differ in phenology, floral traits and sexual and vegetative reproduction, and also not in plastic responses to the watering treatments. However, plants from the invasive range produced twice as many flower-bearing upright side branches than the ones from the native populations. Further, with increasing latitude of collection, vegetative reproduction of our experimental plants increased while sexual reproduction decreased. Plants from the invasive and native range shared these latitudinal clines. Because allozymes showed that the relatedness between native and invasive populations did not depend on latitude, this suggests that plants in the invasive regions have adapted to the local latitude. Overall, our study indicates that quantitative genetic variation of M. guttatus in its two invasive regions is shaped by adaptive evolutionary processes rather than by non-adaptive ones. (C) 2007 Gesellschaft fur Okologie. Published by Elsevier GmbH. All rights reserved.

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The majority of plant species rely, at least partly, on animals for pollination. Our knowledge on whether pollinator visitation differs between native and alien plant species, and between invasive and non-invasive alien species is still limited. Additionally, because numerous invasive plant species are escapees from horticulture, the transition from human-assisted occurrence in urbanized habitats to unassisted persistence and spread in (semi-)natural habitats requires study. To address whether pollinator visitation differs between native, invasive alien and non-invasive alien species, we did pollinator observations for a total of 17 plant species representing five plant families. To test whether pollinator visitation to the three groups of species during the initial stage of invasion depends on habitat type, we did the study in three urbanized habitats and three semi-natural grasslands, using single potted plants. Native plants had more but smaller flower units than alien plants, and invasive alien plants had more but smaller flowers than non-invasive alien plants. After accounting for these differences in floral display, pollinator visitation was higher for native than for alien plant species, but did not differ between invasive and non-invasive alien plant species. Pollinator visitation was on average higher in semi-natural than in urbanized habitats, irrespective of origin or status of the plant species. This might suggest that once an alien species has managed to escape from urbanized into more natural habitats, pollinator limitation will not be a major barrier to establishment and invasion.

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Clonality is frequently positively correlated with plant invasiveness, but which aspects of clonality make some clonal species more invasive than others is not known. Due to their spreading growth form, clonal plants are likely to experience spatial heterogeneity in nutrient availability. Plasticity in allocation of biomass to clonal growth organs and roots may allow these plants to forage for high-nutrient patches. We investigated whether this foraging response is stronger in species that have become invasive than in species that have not. We used six confamilial pairs of native European clonal plant species differing in invasion success in the USA. We grew all species in large pots under homogeneous or heterogeneous nutrient conditions in a greenhouse, and compared their nutrient-foraging response and performance. Neither invasive nor non-invasive species showed significant foraging responses to heterogeneity in clonal growth organ biomass or in aboveground biomass of clonal offspring. Invasive species had, however, a greater positive foraging response in terms of root and belowground biomass than non-invasive species. Invasive species also produced more total biomass. Our results suggest that the ability for strong root foraging is among the characteristics promoting invasiveness in clonal plants.

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The ability of some invasive plant species to produce biochemical compounds toxic to native species, called allelopathy, is thought to be one of the reasons for their success when introduced to a novel range, an idea known as the Novel Weapons Hypothesis. However, support for this hypothesis mainly comes from bioassays and experiments conducted under controlled environments, whereas field evidence is rare. In a field experiment, we investigated whether three plant species invasive in Europe, Solidago gigantea, Impatiens glandulifera and Erigeron annuus, inhibit the germination of native species through allelopathy more than an adjacent native plant community. At three sites for each invasive species, we compared the germination of native species that were sown on invaded and non-invaded plots. Half of these plots were amended with activated carbon to reduce the influence of potential allelopathic compounds. The germination of sown seeds and of seeds from the seedbank was monitored over a period of 9 weeks. Activated carbon generally enhanced seed germination. This effect was equally pronounced in invaded and adjacent non-invaded plots, indicating that invasive species do not suppress germination more than a native plant community. In addition, more seeds germinated from the seedbank on invaded than on non-invaded soil, probably due to previous suppression of germination by the invasive species. Our field study does not provide evidence for the Novel Weapons Hypothesis with respect to the germination success of natives. Instead, our results suggest that if invasive species release allelopathic compounds that suppress germination, they do so to a similar degree as the native plant community.

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BACKGROUND: To investigate if non-rigid image-registration reduces motion artifacts in triggered and non-triggered diffusion tensor imaging (DTI) of native kidneys. A secondary aim was to determine, if improvements through registration allow for omitting respiratory-triggering. METHODS: Twenty volunteers underwent coronal DTI of the kidneys with nine b-values (10-700 s/mm2 ) at 3 Tesla. Image-registration was performed using a multimodal nonrigid registration algorithm. Data processing yielded the apparent diffusion coefficient (ADC), the contribution of perfusion (FP ), and the fractional anisotropy (FA). For comparison of the data stability, the root mean square error (RMSE) of the fitting and the standard deviations within the regions of interest (SDROI ) were evaluated. RESULTS: RMSEs decreased significantly after registration for triggered and also for non-triggered scans (P < 0.05). SDROI for ADC, FA, and FP were significantly lower after registration in both medulla and cortex of triggered scans (P < 0.01). Similarly the SDROI of FA and FP decreased significantly in non-triggered scans after registration (P < 0.05). RMSEs were significantly lower in triggered than in non-triggered scans, both with and without registration (P < 0.05). CONCLUSION: Respiratory motion correction by registration of individual echo-planar images leads to clearly reduced signal variations in renal DTI for both triggered and particularly non-triggered scans. Secondarily, the results suggest that respiratory-triggering still seems advantageous.J. Magn. Reson. Imaging 2014. (c) 2014 Wiley Periodicals, Inc.

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OBJECTIVES This study sought to describe the frequency and clinical impact of acute scaffold disruption and late strut discontinuity of the second-generation Absorb bioresorbable polymeric vascular scaffolds (Absorb BVS, Abbott Vascular, Santa Clara, California) in the ABSORB (A Clinical Evaluation of the Bioabsorbable Everolimus Eluting Coronary Stent System in the Treatment of Patients With De Novo Native Coronary Artery Lesions) cohort B study by optical coherence tomography (OCT) post-procedure and at 6, 12, 24, and 36 months. BACKGROUND Fully bioresorbable scaffolds are a novel approach to treatment for coronary narrowing that provides transient vessel support with drug delivery capability without the long-term limitations of metallic drug-eluting stents. However, a potential drawback of the bioresorbable scaffold is the potential for disruption of the strut network when overexpanded. Conversely, the structural discontinuity of the polymeric struts at a late stage is a biologically programmed fate of the scaffold during the course of bioresorption. METHODS The ABSORB cohort B trial is a multicenter single-arm trial assessing the safety and performance of the Absorb BVS in the treatment of 101 patients with de novo native coronary artery lesions. The current analysis included 51 patients with 143 OCT pullbacks who underwent OCT at baseline and follow-up. The presence of acute disruption or late discontinuities was diagnosed by the presence on OCT of stacked, overhung struts or isolated intraluminal struts disconnected from the expected circularity of the device. RESULTS Of 51 patients with OCT imaging post-procedure, acute scaffold disruption was observed in 2 patients (3.9%), which could be related to overexpansion of the scaffold at the time of implantation. One patient had a target lesion revascularization that was presumably related to the disruption. Of 49 patients without acute disruption, late discontinuities were observed in 21 patients. There were no major adverse cardiac events associated with this finding except for 1 patient who had a non-ischemia-driven target lesion revascularization. CONCLUSIONS Acute scaffold disruption is a rare iatrogenic phenomenon that has been anecdotally associated with anginal symptoms, whereas late strut discontinuity is observed in approximately 40% of patients and could be viewed as a serendipitous OCT finding of a normal bioresorption process without clinical implications. (ABSORB Clinical Investigation, Cohort B [ABSORB B]; NCT00856856).