2,563 research outputs found

    High variability in nest site selection in a loggerhead turtle rookery, in Boa Vista Island, Cabo Verde

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    Among sea turtles, nest site selection is a crucial factor for hatching success and population viability. The relocation of otherwise doomed clutches to safe hatcheries has been widely promoted as a conservation strategy, although this may promote artificial selection of poorly adapted genotypes. In this study, we used multiyear spatial nesting data of individual loggerhead turtles (Caretta caretta) from one of the largest Atlantic rookeries, in Cabo Verde, across six consecutive nesting seasons (2013–2018), to identify spatial nesting patterns, assess how individual nest site selection is influenced by female size and age, and estimate the impacts on the reproductive output. Although females nested across the entire beach width, they preferentially nested in the middle of the beach, avoiding to nest both close to the tideline and close to the vegetation line. Hatching success decreased towards the waterline, while the risk of nest inundation or predation was high, regardless of nest location. In general, females showed high variability in nest site selection, except larger females (> 93 cm curved carapace length) that showed higher repeatability (r = 0.50, SE = 0.14, 95% CI: 0.16–0.72) in distances to the vegetation. We therefore suggest that the relocation of doomed clutches should be considered for this endangered rookery, as clutch relocation should not substantially distort the gene pool, assuming nest choice is a heritable trait. In addition, we recommend the preservation of beach vegetation, particularly in areas with human developmet.info:eu-repo/semantics/publishedVersio

    Risk assessment of wildlife-watching tourism in an important endangered loggerhead turtle rookery

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    T: Wildlife-watching tourism is a non-exploitative activity that can contribute to sustainable economic development of coastal communities. However, it is important to assess the potential impact and implement best practices to mitigate any negative effects of such tourism. We studied this issue on Boa Vista (Cabo Verde), which supports around 60% of nesting activity of one of the most endangered loggerhead turtle rookeries globally. Between 2013 and 2016, authorized turtle watching involved 4942 tourists, generating a mean annual direct income of >USD 289 000 and the direct creation of >250 jobs. On João Barrosa beach, which supports around 20% of nests and 48% of turtle-watching activity on the island, we tested the influence of turtle watching on nesting behavior, reproduction and nest-site fidelity. Nesting females observed by tourists spent significantly less time on nest-camouflaging behavior, although all other phases of nesting were unaffected. There were no statistically significant differences between the re-nesting frequency of females watched (n = 187) and non-watched (n = 972) by tourists. We found no evidence that the current turtle-watching intensity has an effect on turtle reproduction. Turtle poaching remains a severe threat on beaches with no turtle watching, although it has strongly decreased on beaches with tourist visits. We suggest tour guides follow best practice guidelines to minimize disturbance, specifically retreating from the immediate vicinity of a female during nest camouflaging to mitigate the observed impact.Peer reviewe

    Wideband and wide beam polyvinylidene difluoride (PVDF) acoustic transducer for broadband underwater communications

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    The advances in wireless communications are still very limited when intended to be used on Underwater Communication Systems mainly due to the adverse proprieties of the submarine channel to the acoustic and radio frequency (RF) waves propagation. This work describes the development and characterization of a polyvinylidene difluoride ultrasound transducer to be used as an emitter in underwater wireless communications. The transducer has a beam up to 10° × 70° degrees and a usable frequency band up to 1 MHz. The transducer was designed using Finite Elements Methods and compared with real measurements. Pool trials show a transmitting voltage response (TVR) of approximately 150 dB re µPa/V@1 m from 750 kHz to 1 MHz. Sea trials were carried in Ria Formosa, Faro (Portugal) over a 15 m source-receiver communication link. All the signals were successfully detected by cross-correlation using 10 chirp signals between 10 to 900 kHz.Agência financiadora Programa Operacional Regional do Norte (NORTE2020), through Fundo Europeu de Desenvolvimento Regional (FEDER) NORTE-01-0145-FEDER-000032-NextSea Fundacao para a Ciencia e a Tecnologia (FCT) UID/EEA/04436/2019 SFRH/BPD/107826/2015 MIT-EXPL/IRA/0070/2017info:eu-repo/semantics/publishedVersio

    Optimization of the etch-and-rinse technique : New perspectives to improve resin–dentin bonding and hybrid layer integrity by reducing residual water using dimethyl sulfoxide pretreatments

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    Objective. To determine whether bonding effectiveness and hybrid layer integrity on acid-etched dehydrated dentin would be comparable to the conventional wet-bonding technique through new dentin biomodification approaches using dimethyl sulfoxide (DMSO). Methods. Etched dentin surfaces from extracted sound molars were randomly bonded in wet or dry conditions (30 s air drying) with DMSO/ethanol or DMSO/H2O as pretreatments using a simplified (Scotchbond Universal Adhesive, 3M ESPE: SU) and a multi-step (Adper Scotchbond Multi-Purpose, 3M ESPE: SBMP) etch-and-rinse adhesives. Untreated dentin surfaces served as control. Bonded teeth (n=8) were stored in distilled water for 24 h and sectioned into resin-dentin beams (0.8 mm(2)) for microtensile bond strength test and quantitative interfacial nanoleakage analysis (n = 8) under SEM. Additional teeth (n = 2) were prepared for micropermeability assessment by CFLSM under simulated pulp ar pressure (20 cm H2O) using 5 mM fluorescein as a tracer. Microtensile data was analyzed by 3-way ANOVA followed by Tukey Test and nanoleakage by Kruskal-Wallis and Dunn-Bonferroni multiple comparison test (alpha = 0.05). Results. While dry-bonding of SBMP produced significantly lower bond strengths than wet-bonding (p Conclusion. DMSO pretreatments may be used as a new suitable strategy to improve bonding of water-based adhesives to demineralized air-dried dentin beyond conventional wetbonding. Less porous resin-dentin interfaces with higher bond strengths on air-dried etched dentin were achieved; nonetheless, overall efficiency varied according to DMSO's co-solvent and adhesive type. Clinical significance. DMSO pretreatments permit etched dentin to be air-dried before hybridization facilitating residual water removal and thus improving bonding effectiveness. This challenges the current paradigm of wet-bonding requirement for the etch-and-rinse approach creating new possibilities to enhance the clinical longevity of resin-dentin interfaces. (C) 2018 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved.Peer reviewe

    In Vivo Biodistribution of Respirable Solid Lipid Nanoparticles Surface-Decorated with a Mannose-Based Surfactant: A Promising Tool for Pulmonary Tuberculosis Treatment?

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    The active targeting to alveolar macrophages (AM) is an attractive strategy to improve the therapeutic efficacy of ‘old’ drugs currently used in clinical practice for the treatment of pulmonary tuberculosis. Previous studies highlighted the ability of respirable solid lipid nanoparticle assemblies (SLNas), loaded with rifampicin (RIF) and functionalized with a novel synthesized mannose-based surfactant (MS), both alone and in a blend with sodium taurocholate, to efficiently target the AM via mannose receptor-mediated mechanism. Here, we present the in vivo biodistribution of these mannosylated SLNas, in comparison with the behavior of both non-functionalized SLNas and bare RIF. SLNas biodistribution was assessed, after intratracheal instillation in mice, by whole-body real-time fluorescence imaging in living animals and RIF quantification in excised organs and plasma. Additionally, SLNas cell uptake was determined by using fluorescence microscopy on AM from bronchoalveolar lavage fluid and alveolar epithelium from lung dissections. Finally, histopathological evaluation was performed on lungs 24 h after administration. SLNas functionalized with MS alone generated the highest retention in lungs associated with a poor spreading in extra-pulmonary regions. This effect could be probably due to a greater AM phagocytosis with respect to SLNas devoid of mannose on their surface. The results obtained pointed out the unique ability of the nanoparticle surface decoration to provide a potential more efficient treatment restricted to the lungs where the primary tuberculosis infection is located

    Dentin bond optimization using the dimethyl sulfoxide-wet bonding strategy : A 2-year in vitro study

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    Objective. This study evaluated a new approach, named dimethyl sulfoxide (DMSO)-wet bonding, to produce more desirable long-term prospects for the ultrafine interactions between synthetic polymeric biomaterials and the inherently hydrated dentin substrate. Methods. Sound third molars were randomly restored with/without DMSO pretreatment using a total-etch (Scocthbond Multipurpose: SBMP) and a self-etch (Clearfil SE Bond: CF) adhesive systems. Restored teeth (n = 10)/group were sectioned into sticks and submitted to different analyses: micro-Raman determined the degree of conversion inside the hybrid layer (DC); resin dentin microtensile bond strength and fracture pattern analysis at 24 h, 1 year and 2 years of aging; and nanoleakage evaluation at 24h and 2 years. Results. DMSO-wet bonding produced significantly higher 24 h bond strengths for SBMP that were sustained over the two-year period, with significantly less adhesive failures. Similarly, DMSO-treated CF samples presented significantly higher bond strength than untreated samples at two years. Both adhesives had significant less adhesive failures at 2 years with DMSO. DMSO had no effect on DC of SBMP, but significantly increased the DC of CE DMSO-treated SBMP samples presented reduced silver uptake compared to untreated samples after aging. Significance. Biomodification of the dentin substrate by the proposed strategy using DMSO is a suitable approach to produce more durable hybrid layers with superior ability to withstand hydrolytic degradation over time. Although the active role of DMSO on dentin bond improvement may vary according to monomer composition, its use seems to be effective on both self-etch and etch-and-rinse bonding mechanisms. (C) 2016 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.Peer reviewe

    Desempenho agronômico de novos cultivares de morango no sul do Brasil

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    The choice of cultivars to be used by strawberry farmers is essential since it could determine the success of the crop. The present study aimed to evaluate the productive and qualitative performance of strawberry genotypes grown in Vacaria, RS, Brazil. Twelve strawberry genotypes were compared, constituting the different treatments: cultivars Strawberry Festival, Oso Grande, Jonica, and Pircinque, and selections FRF PA3, FRF CE 51, FRF CE 56, FRF PIR 29, FRF PIR 54, FRF 85.04, FRF 149.18, and FRF 102.21. The seedlings were transplanted on May 13, 2014, in a semi-hydroponic cultivation system, adopting a randomized block design with four blocks and an experimental unit of ten useful plants. The variables evaluated were the number of fruits, total production per plant, productivity, commercial productivity, fresh fruit mass, commercial percentage, soluble solids, titratable acidity, soluble solids to total acidity ratio, pulp firmness, and production seasonality. The mean values ​​were subjected to an analysis of variance and multivariate analysis, and their means were compared by the Scott-Knott test at a 5% error probability. Cultivar Strawberry Festival and selection FRF 102.21 showed higher productions (1138 g plant-1 nd 1019 g plant-1, respectively) and quantities of fruits produced (85 un plant-1 and 87 un plant-1, respectively). Cultivar Jonica and selection FRF 85.4 showed higher percentages of marketable fruits. The Pircinque cultivar was prominent for sugar content, presenting a value 24% superior to the general average of the cultivars. Cultivars Strawberry Festival, Jonica, and Pircinque and selection FRF 102.21 showed the highest qualitative and quantitative gains for the region of Vacaria, RS, Brazil.A escolha dos cultivares a serem utilizadas pelos produtores de morangos é fundamental, pois pode determinar o sucesso da cultura. O presente estudo tem como objetivo avaliar o desempenho produtivo e qualitativo de genótipos de morangueiro cultivados em Vacaria, RS, Brasil. Foram comparados 12 genótipos de morangueiro, constituindo os diferentes tratamentos: cultivares Strawberry Festival, Oso Grande, Jonica e Pircinque, e seleções FRF PA3, FRF CE 51, FRF CE 56, FRF PIR 29, FRF PIR 54, FRF 85,04, FRF 149,18, e FRF 102,21. As mudas foram transplantadas em 13 de maio de 2014, em sistema de cultivo semi-hidropônico, adotando-se o delineamento em blocos casualizados, com quatro blocos e unidade experimental de dez plantas úteis. As variáveis ​​avaliadas foram número de frutos, produção total por planta, produtividade, produtividade comercial, massa fresca do fruto, porcentagem comercial, sólidos solúveis, acidez titulável, relação (sólidos solúveis/acidez total), firmeza da polpa e a sazonalidade da produção. Os valores médios foram submetidos à análise de variância e análise multivariada, e suas médias comparadas pelo teste de Scott-Knott a 5% de probabilidade de erro. O cultivar Strawberry Festival e seleção FRF 102,21 apresentaram maior produção (1138 e 1019 g planta-1) e quantidade de frutos produzidos (85 e 87 un planta-1). A cultivar Jonica e a seleção FRF 85,4 apresentaram maior porcentagem de frutos comerciáveis. O cultivar Pircinque se destacou-se pelo seu teor de açúcares, apresentando um valor 24% superior à média geral dos cultivares. As cultivares Strawberry Festival, Jonica e Pircinque e seleção FRF 102,21 apresentaram os maiores ganhos qualitativos e quantitativos para a região de Vacaria, RS.
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