Beach and cliff retreat induced by storm groups at Forte Novo,Algarve (Portugal)

Littoral cell dynamics may change through time as a reaction to modifications of the coastal system. Along the Vilamoura-Quarteira coastline, the construction of a groin field limited the sediment supply to the already narrow Forte Novo beach, located downdrift, enhanced wave action on the cliff base and lead to long-term persistent cliff retreat. This research uses a set of surveys from November 2009 to March 2010 to determine short-term soft cliff erosion associated to storm groups at this sediment starved area. Following the initial LiDAR survey, three subsequent surveys were performed using a reflectorless total station for monitoring the cliff face, and RTK-DGPS to monitor the position of the cliff top, the cliff foot and the topography of the adjacent beach. Results indicate an important reduction in beach levels during successive storms (without significant beach recovery in between), allowing waves to further attack the cliff base and contributing to further enhance the structural and permanent cliff retreat. This work demonstrates how a combination of magnitude and frequency of extreme events coupled with development of the coastline, has led to increased cliff-beach recession and to the permanent dislocation of the cliff face

Synthesis and properties of Co-doped titanate nanotubes and their optical sensitization with methylene blue

Here we report on a novel chemical route to synthesize homogenous cobalt doped titanate nanotubes (CoTNT), using an amorphous Co-doped precursor. The influence of the synthesis temperature, autoclave dwell time and metal doping on the structural and microstructural as well as on the optical properties of the synthesized titanate nanotubes is studied and discussed. The optical band gaps of the CoTNT samples are red shifted in comparison with the values determined for the undoped samples, such red shifts bringing the absorption edge of the CoTNT samples into the visible region. CoTNT materials also demonstrate particular high adsorption ability for methylene blue, the amount of the adsorbed dye being higher than the one predictable for a monolayer formation. This suggests the possibility of intercalation of the dye molecule between the TiO6 layers of the TNT structure. It is also shown that the methylene blue sensitized Co-doped nanostructures are highly stable under UV radiation and present a strong and broad absorption in the visible region.Comment: 31 pages, 3 tables, 7 figure

Nucleosynthesis Constraints on a Scale-Dependent New Intermediate Range Interaction

We derive constraints on the strength of a new intermediate range interaction that couples to baryon number from primordial nucleosynthesis yields. The nucleosysnthesis limits here used arise from matching observations and predictions of standard and inhomogeneous primordial scenarios. We show that the standard nucleosynthesis scenario is more restrictive (\alpha_5 \lsim 0.2) when the range of the interaction is greater than about 1 m. We further discuss the implications of considering the scalar particle responsible for the new interaction as the main component of the dark matter in the galactic halo such that its decay can account for the ionization of hydrogen in the interstellar medium and the temperature of Lyman-$\alpha$ clouds.Comment: 14 pages, Latex plus 2 eps figures. To be published in Physics Letters

Sharing economy: the establishment of organizational identity overtime, considering identify claims and legitimacy granting

The Sharing Economy (SE) has been growing at an impressive rate across the globe (Cohen & Kietzmann, 2014) and emerging as an innovative and rapidly growing sector of the economy (Hira & Reilly, 2017), which attracted the attention of the scientific community. An increasing number of studies have been brought to light helping to document and analyze how SE manifests and evolves across economic systems, thus, contributing to refine and recast existing management theory (Mair & Reischauer, 2017). Nevertheless, there still is a lack of a common understanding of SE and its underlying mechanisms (Knote & Blohm, 2016). As an emergent category, SE has been contoured by being a mutant process, as it has been crafted by multiple and distinct temporal identity and legitimacy events, mechanisms and claims. Showing signs of being an on-going process of evolution, there is a constant need for further research to identify developments in the evolution of SE considering both identify claims (self-referential) and legitimacy (granted by stakeholders), which would offer additional comprehension about the SE phenomenon. The research addresses it by studying what is the role of SE in establishing the identity of organizations belonging to the field, considering both identify claims (self-referential) and legitimacy (granted by stakeholders)? To answer the research question, the research was designed involving two components inspired on category creation studies (Durand & Paolella, 2013; Glynn & Navis, 2013; Navis & Glynn, 2010; Kennedy & Fiss, 2013; Kennedy et al., 2010; Lounsbury & Rao, 2004; and Wry et al., 2014): 1) four prototypical SE organizations were selected, each of them belonging to Schor’s (2014) four SE archetypes of activities: (i) Airbnb – peer-to-peer, for-profit activity –, (ii) Zipcar – business-to-peer, for-profit activity –, (iii) TimeBanks – peer-to-peer, non-profit – and (iv) Make: makerspaces – business-to-peer, non-profit. The content of the evolution of their identity claims was analyzed, using data from their public available reports, as well as, other secondary data available on-line; and 2) considering the same set of SE organizations, legitimacy evolution was analyzed considering how scientific community, investors, customers, media, other analysts and other interested audiences have been constructing category meaning to them, conferring the formation of SE categorical and organizational identities, and perceptions about the viability of their business models (Tripsas, 2009, as cited in Navis & Glynn, 2010). In short, it was analyzed how stakeholders assess the viability of SE categories and organizations and can grant or withhold legitimacy to SE organizations (Zuckerman, 1999, as cited in Navis & Glynn, 2010). This research presents a new layer on framing a detailed understanding of the SE field in its maturing dimension, thus, meeting Mair’s and Reischauer’s (2017) call for studying the SE, unpack and make sense of an inspiring and complex phenomenon and thereby advancing and sophisticate the existing theory.info:eu-repo/semantics/publishedVersio

Sharing economy: The establishment of organizational identity overtime, considering identify claims and legitimacy granting

The Sharing Economy (SE) has been growing at an impressive rate across the globe (Cohen & Kietzmann, 2014) and emerging as a new and rapidly growing sector of the economy (Hira & Reilly, 2017), which has the effect of attracting the attention of the scientific community over the last few years. An increasing number of studies on the topic have been brought to light helping to document and analyse how SE manifests and evolves across various economic systems, thus, contributing to refine and recast existing management theory (Mair & Reischauer, 2017). Nonetheless, there still is a lack of common understanding of SE and its underlying mechanisms (Knote & Blohm, 2016). As an emergent category, SE has been contoured by being a mutant process, as it has been crafted by multiple and distinct temporal identity and legitimacy events, mechanisms and claims. Showing signs of being an on-going process of evolution, there is a constant need for further research on identifying new developments in the evolution of SE considering both identify claims (self-referential) and legitimacy (granted by stakeholders), which would offer additional comprehension about the SE phenomenon. In this research, we address these by studying what is the role of SE in establishing the identity of organizations belonging to the field, considering both identify claims (self-referential) and legitimacy (granted by stakeholders)? To answer this research question, we designed a research involving two components inspired on category creation studies (Durand & Paolella, 2013; Glynn & Navis, 2013; Navis & Glynn, 2010; Kennedy & Fiss, 2013; Kennedy et al., 2010; Lounsbury & Rao, 2004; and Wry et al., 2014): 1) four prototypical SE organizations were selected, each of them belonging to Schor’s (2014) four SE archetypes of activities. Respectively: (i) Airbnb – peer-to-peer, for-profit activity –, (ii) Zipcar – business-to-peer, for-profit activity –, (iii) TimeBanks – peer-to-peer, non-profit – and (iv) Make: makerspaces – business-to-peer, non-profit. The evolution of their identity claims were content analysed, using data from their publically available reports, as well as, other secondary data available on-line; and 2) considering the same set of SE organizations, legitimacy evolution was analysed considering how scientific community, investors, customers, media, other analysts and other interested audiences have been constructing category meaning to them, conferring the formation of SE categorical and organizational identities, and perceptions about the viability of their business models (Tripsas, 2009, as cited in Navis & Glynn, 2010). In short, it was analysed how audiences assess the viability of SE categories and organizations and can grant or withhold legitimacy to SE organizations (Zuckerman, 1999, as cited in Navis & Glynn, 2010). This paper presents a new layer on framing a detailed understanding of the SE field in its maturing dimension, thus, meeting Mair and Reischauer’s (2017) call for studying the SE, unpack and make sense of an inspiring and complex phenomenon and thereby to advance and refine existing theory.info:eu-repo/semantics/publishedVersio

DNA-psoralen: single-molecule experiments and first principles calculations

The authors measure the persistence and contour lengths of DNA-psoralen complexes, as a function of psoralen concentration, for intercalated and crosslinked complexes. In both cases, the persistence length monotonically increases until a certain critical concentration is reached, above which it abruptly decreases and remains approximately constant. The contour length of the complexes exhibits no such discontinuous behavior. By fitting the relative increase of the contour length to the neighbor exclusion model, we obtain the exclusion number and the intrinsic intercalating constant of the psoralen-DNA interaction. Ab initio calculations are employed in order to provide an atomistic picture of these experimental findings.Comment: 9 pages, 4 figures in re-print format 3 pages, 4 figures in the published versio

Synthesis of sub-5 nm Co-doped SnO2_2 nanoparticles and their structural, microstructural, optical and photocatalytic properties

A swift chemical route to synthesize Co-doped SnO$_2$ nanopowders is described. Pure and highly stable Sn$_{1-x}$Co$_x$O$_{2-\delta}$ (0 $\le$ x $\le$ 0.15) crystalline nanoparticles were synthesized, with mean grain sizes < 5 nm and the dopant element homogeneously distributed in substitutional sites of the SnO$_2$ matrix. The UV-visible diffuse reflectance spectra of the Sn$_{1-x}$Co$_x$O$_{2-\delta}$ samples reveal red shifts, the optical bandgap energies decreasing with increasing Co concentration. The Urbach energies of the samples were calculated and correlated with their bandgap energies. The photocatalytic activity of the Sn$_{1-x}$Co$_x$O$_{2-\delta}$ samples was investigated for the 4-hydroxylbenzoic acid (4-HBA) degradation process. A complete photodegradation of a 10 ppm 4-HBA solution was achieved using 0.02% (w/w) of Sn$_{0.95}$Co$_{0.05}$O$_{2-\delta}$ nanoparticles in 60 min of irradiation.Comment: 29 pages, 2 tables, 10 figure

Cell-element simulations to optimize the performance of osmotic processes in porous membranes

We present a new module of the software tool PoreChem for 3D simulations of osmotic processes at the cell-element scale. We consider the most general fully coupled model (see e.g., Sagiv and Semiat (2011)) in 3D to evaluate the impact on the membrane performance of both internal and external concentration polarization, which occurs in a cell-element for different operational conditions. The model consists of the Navier–Stokes–Brinkman system to describe the free fluid flow and the flow within the membrane with selective and support layers, a convection–diffusion equation to describe the solute transport, and nonlinear interface conditions to fully couple these equations. First, we briefly describe the mathematical model and discuss the discretization of the continuous model, the iterative solution, and the software implementation. Then, we present the analytical and numerical validation of the simulation tool. Next, we perform and discuss numerical simulations for a case study. The case study concerns the design of a cell element for the forward osmosis experiments. Using the developed software tool we qualitatively and quantitatively investigate the performance of a cell element that we designed for laboratory experiments of forward osmosis, and discuss the differences between the numerical solutions obtained with the full 3D and reduced 2D models. Finally, we demonstrate how the software enables investigating membrane heterogeneities

Comparação de diferentes procedimentos de estimulação elétrica neuromuscular utilizados no tratamento da incontinência urinária de esforço feminina: ensaio clínico randomizado

BACKGROUND: Neuromuscular electrical stimulation (NMES) is widely treatment for stress urinary incontinence (SUI) but there is no consensus in literature regarding the most effective treatment parameters. OBJECTIVE: To compare two NMESintra-vaginal protocols for the treatment of SUI in women. METHODS: The study included 20 volunteers with an average age of 55.55±6.51 years and with the clinical diagnosis of SUI. Volunteers were randomly divided into two groups: group 1 (G1) received NMES with medium-frequency current and group 2 (G2) received NMES with low-frequency current. Functional assessments of pelvic floor muscles (PFM) were performed by perineometry. The severity of signs and symptoms were objectively evaluated using the 1 hour pad test and subjectively evaluated using a visual analog scale that measured the discomfort caused by the SUI. Shapiro-Wilk test was used to analyze data normality, and the Friedman test was used to analyze nonparametric data. For analysis of symptoms related to SUI the Fisher exact test and the Mann-Whitney test were used. Significance level of 5% was set for all data analysis. RESULTS: No significant differences (p&gt;0.05) were found between groups for any of the variable assessed. The within group analysis of initial and final evaluations (after NMES) demonstrated significant differences (p<0.05) in amount of urine lost, the discomfort caused by urinary incontinence and perineal pressure for both treatment groups. CONCLUSION: The two NMES protocols applied were equally effective in the treatment of SUI.CONTEXTUALIZAÇÃO: A estimulação elétrica neuromuscular (EENM) é amplamente utilizada no tratamento da incontinência urinária de esforço (IUE), no entanto não há consenso na literatura sobre os parâmetros de tratamento mais eficazes. OBJETIVO: Avaliar os procedimentos de EENM intravaginal no tratamento de mulheres com IUE. MÉTODOS: Participaram do estudo 20 voluntárias com idade média de 55,55±6,51 anos, com diagnóstico clínico de IUE. As voluntárias foram divididas aleatoriamente em dois grupos: grupo 1 (G1), que recebeu EENM com corrente de média frequência, e grupo 2 (G2), com corrente de baixa frequência. A avaliação funcional dos músculos do assoalho pélvico (MAP) foi realizada por meio de perineometria, e a severidade dos sinais e sintomas da IUE foi avaliada, objetivamente, pelo pad test de uma hora e, subjetivamente, pela Escala Visual Analógica (EVA), que mediu o desconforto causado pela incontinência. Para a análise de normalidade dos dados, utilizou-se o teste Shapiro-Wilk, seguido do teste de Friedman para dados não paramétricos. Para a análise dos sintomas relacionados à IUE, usaram-se os testes Exato de Fisher e Mann-Whitney. Em todas as análises, considerou-se o nível de significância de 5%. RESULTADOS: Não houve diferença significativa (p&gt;0,05) entre os grupos em nenhuma variável avaliada. Na comparação intragrupos das avaliações iniciais e finais (após EENM), houve diferença significativa (p<0,05) na quantidade de urina perdida, no desconforto causado pela incontinência urinária e na pressão perineal. CONCLUSÃO: Os procedimentos de EENM utilizados neste estudo foram igualmente eficazes no tratamento da IUE