Effects of a large irrigation reservoir on aquatic and riparian plants: a history of survival and loss

Dammed rivers have unnatural stream flows, disrupted sediment dynamics, and rearranged geomorphologic settings. Consequently, fluvial biota experiences disturbed functioning in the novel ecosystems. The case study is the large irrigation reservoir Alqueva in Guadiana River, Southern Iberia. The study area was divided into three zones: upstream and downstream of the dam and reservoir. For each zone, species composition and land use and land cover (LULC) were compared before and after the Alqueva Dam implementation. Data consist of aquatic and riparian flora composition obtained from 46 surveys and the area (%) of 12 classes of LULC obtained in 90 riverine sampling units through the analysis of historical and contemporary imagery. There was an overall decrease of several endemic species and on the riparian shrublands and aquatic stands, although di erences in the proportion of functional groups were not significant. Nevertheless, compositional diversity shows a significant decline in the upstream zone while landscape diversity shows an accentuated reduction in the reservoir area and downstream of the dam, which is likely related to the loss of the rocky habitats of the ‘old’ Guadiana River and the homogenization of the riverscape due to the irrigation intensification. The mitigation of these critical changes should be site-specific and should rely on the knowledge of the interactions between surrounding lands, ecological, biogeomorphologic, and hydrological components of the fluvial ecosystemsinfo:eu-repo/semantics/publishedVersio

Nanotechnology applied to medical biofilms control

Nanoscience and Nanotechnology (N&N) are new approaches to research phenomena at atomic, molecular and macromolecular scales, where properties differ significantly from those at a larger scale. This new approach can be applied to microbial biofilms, which are formed when bacterial and/or yeast cells adhere to abiotic and biotic surfaces. It is well known that microorganisms in biofilms have a different behaviour from their planktonic counterparts, demonstrating a general recalcitrance to medical therapy. Therefore, biofilm-associated infections on indwelling medical devices, such as catheters and prostheses, may persist even after suspension of antibiotic therapy and hence may require the removal of the device. In order to reduce patient`s morbidity and mortality, as well as high economical costs associated to medical biofilms, several attempts have been made to develop novel mechanisms of biofilm prevention and/or elimination. In this mini-review, the current knowledge on the features of biofilm formation and their relevance to medical device-associated infections are enclosed, as well as the new anti-biofilm approaches based on nanotechnology.The support by Portuguese Foundation for Science and Technology through the grants SFRH/BPD/47693/2008 and SFRH/BPD/20987/2004 is gratefully acknowledged

The effectiveness of e-word-of-mouth communication about smartphones purchase intention: digital influencer

This study aims to compare the effectiveness of eWOM on Facebook, Instagram and YouTube for smartphone buying decision, provided by digital influencers. For such, a quantitative methodology was adopted using three online questionnaires (one for each social media platform), to be answered by Portuguese adults who use them. This comparison has foundation on the IACM, a model introduced by Erkan and Evans to explore the influence of eWOM on consumer's buying intentions. The results show that, while the eWOM information from digital influencers about smartphones has a global consumer receptivity in the three social media platforms considered, that is not happening in a very assertive way for some items [average not greater than 3 (Likert scale 1-5)], in a significant statistically way. The research also demonstrate that YouTube or Instagram are more effective than Facebook in the IACM variables 'information quality', 'information credibility', 'information usefulness', 'positive buying intention with digital influencer positive information' and 'negative buying intention with digital influencer negative information'.info:eu-repo/semantics/acceptedVersio

Can Wheat Germ Have a Beneficial Effect on Human Health? A Study Protocol for a Randomised Crossover Controlled Trial to Evaluate its Health Effects

INTRODUCTION: Cardiovascular diseases (CVD) are the leading cause of mortality worldwide and diet is an important contributor to CVD risk. Thus, several food derivatives are being investigated for their beneficial impact on reducing cardiometabolic risk factors, either in risk groups or in healthy population as a preventive measure. Wheat germ is a food by-product with high nutritional value, especially as a concentrated source of dietary fibre and essential fatty acids, but its incorporation into the diet has been rare up to now. Previous studies do not clarify the hypothesised potential causal relationship between the consumption of wheat germ and benefits for human health. METHODS AND ANALYSIS: We are conducting a randomised, double-blinded, crossover, placebo-controlled clinical trial designed to assess the physiological effects of daily consumption of wheat germ-enriched bread (containing 6 g of wheat germ) compared with non-enriched bread, over a 4-week period with a 15-week follow-up, in a healthy human population. A total of 55 participants (healthy volunteers, aged 18-60) have been recruited from the Porto metropolitan area in northern Portugal. Our aim is to evaluate the health effects of wheat germ on blood cholesterol and triglycerides, postprandial glycaemic response, gastrointestinal function and discomfort, and changes in intestinal microbiota and insulin resistance as secondary outcomes. The study follows the best practices for evaluating health claims in food according to the European Food Safety Authority (EFSA) scientific opinion, namely random allocation, double blinding, reporting methods to measure and maximise compliance, and validated outcomes with beneficial physiological effects as recommended by EFSA. ETHICS AND DISSEMINATION: The study has been approved by the Health Ethics Committee of São João Hospital Centre (156-15) and the Ethics Committee of Faculty of Medicine of the University of Porto (PCEDCSS-FMUP07/2015). Results will be disseminated through peer-reviewed publications and presentations at international scientific meetings.info:eu-repo/semantics/publishedVersio

Matrices in A(R,S) with minimum t-term ranks

Fundacao para a Ciencia e a Tecnologia through the projects UID/MAT/00297/2019 and UID/MAT/00212/2019.Let R and S be two sequences of nonnegative integers in nonincreasing order which have the same sum, and let A(R,S) be the class of all (0,1)-matrices which have row sums given by R and column sums given by S. For a positive integer t, the t-term rank of a (0,1)-matrix A is defined as the maximum number of 1's in A with at most one 1 in each column and at most t 1's in each row. In this paper, we address conditions for the existence of a matrix in A(R,S) that realizes all the minimum t-term ranks, for t≥1.authorsversionpublishe

Validity and reliability of the Parental Homework Management Scale

Background: Prior research has shown that parents help their children manage homework (i.e. environment, time, motivation and emotion management), especially in elementary school. However, researchers have not developed and validated a scale focused on those dimensions. Method: The purpose of the present study is to validate the Parental Homework Management Scale (PHMS) for parents of elementary school children in the domain of mathematics. A sample of 2,118 parent-child dyads was split randomly into two groups to conduct the analysis in two stages: (i) exploratory factor analysis on Group 1 and (ii) confi rmatory factor analysis on Group 2. Results: PHMS is comprised of two distinct but related factors (i.e. environment-time and motivation-emotion management). Results further indicated that the PHMS was positively related to homework self-regulation and positive emotions, and negatively related to math achievement. Contrary to expectations, no relationship was found between PHMS and amount of student homework completed. Conclusions: The scale revealed good psychometric quality.Validación y fi abilidad de la escala de gestión de tareas para casa para padres. Antecedentes: investigaciones previas revelaron que los padres ayudan a sus hijos a gestionar las tareas para casa (i.e., el ambiente, el tiempo, la motivación y las emociones), especialmente en la escuela primaria. Sin embargo, la investigación no ha construido y validado una escala enfocada en esas dimensiones. Método: el presente estudio valida el Parental Homework Management Scale (PHMS) para padres de niños de escuela primaria en el dominio de las matemáticas. Una muestra de 2,118 díadas padres-hijos se dividió aleatoriamente en dos grupos para realizar el análisis en dos etapas: (i) análisis factorial exploratorio en el Grupo 1 y (ii) análisis factorial confi rmatorio en el Grupo 2. Resultados: PHMS está compuesto por dos factores distintos pero relacionados (i.e., gestión del ambiente-tiempo y de la motivación-emoción). Los resultados indicaron además que el PHMS se relacionó positivamente con la autorregulación y las emociones positivas en las tareas para casa, y se relacionó negativamente con el rendimiento en matemáticas. Contrario a las expectativas, no se encontró relación entre PHMS y la cantidad de tareas completadas por los estudiantes. Conclusiones: la escala ha revelado una buena calidad psicométrica.This work was supported by Portuguese Foundation for Science and Technology (FCT) and the Portuguese Ministry of Science (UID/PSI/01662/2013). JC was supported by a PhD fellowship from the Portuguese FCT (SFRH/BD/95341/2013)

Comparison of the extracellular polymeric substances of Candida albicans and Candida dubliniensis biofilms

Candida albicans and Candida dubliniensis live as benign commensal organisms in the oral cavity of both healthy and unhealthy individuals behaving, under certain conditions, as opportunistic pathogens, causing candidiasis. These two Candida species have been mismatched for years, but recently Candida dubliniensis was recovered from the mouth of imunnosupressed patients and identified as a different species. Candidiasis is usually related with the Candida capacity of forming biofilms on inert or biological surfaces, being this phenotype associated with infections. Biofilms are complex structures of microbial communities attached to a surface, in which microorganisms are embedded in a matrix of extracellular polymeric substances (EPS), composed mainly by proteins and polysaccharides. The biofilm matrix holds the potential of determining possible mechanisms of resistance of Candida biofilms. Several factors are known as affecting the production of EPS, namely, growth medium, growth phase and substratum. This study focused the influence of artificial saliva growth medium in the composition of EPS of biofilms formed by both Candida albicans and Candida dubliniensis strains. Biofilms of one strain of Candida albicans and two strains of Candida dubliniensis were formed in an artificial saliva growth medium (ASGM) and compared with those formed in Sabouraud Dextrose Broth (SDB) and analysed after 48h.The differences between the EPS of biofilms were evaluated (after sonication) in terms of proteins (quantified using the BCA protein assay kit) and polysaccharides (quantified using the phenol-sulphuric method). Proteins were also analysed by SDS-PAGE. In SDB the amount of proteins and polysaccharides in the EPS of biofilms formed by Candida albicans was lower than in the EPS of biofilms formed by Candida dubliniensis strains. In the presence of ASGM the amount of proteins and polysaccharides was similar among the EPS of biofilms of Candida albicans and one of the Candida dubliniensis strains and was lower in biofilms of Candida albicans than in biofilms of the other Candida dubliniensis. Analysis of protein profiles obtained by SDS-PAGE showed that all strains present similar patterns independently of the medium of biofilm formation. Biofilms formed in ASGM originated different amounts of EPS, either in terms of polysaccharides or proteins, compared to the ones formed in SDB. Differences were also found in the profile of extracellular proteins of each strain, depending on the medium

Potential of the adhesion of bacteria isolated from drinking water to materials

Heterotrophic bacteria (11 genera, 14 species, 25 putative strains) were isolated from drinking water, identified either biochemically or by partial 16s rDNA gene sequencing and their adherence characteristics were determined by two methods: i. thermodynamic prediction of adhesion potential by measuring hydrophobicity (contact angle measurements) and ii. by measuring adherence to eight different substrata (ASI 304 and 316 stainless steel, copper, polyvinyl chloride, polypropylene, polyethylene, silicone and glass). All the test organisms were hydrophilic and inter-species variation in hydrophobicity occurred only for Comamonas acidovorans. Stainless steel 304 (SS 304), copper, polypropylene (PP), polyethylene (PE) and silicone thermodynamically favoured adhesion for the majority of test strains (>18/25), whilst adhesion was generally less thermodynamically favorable for stainless steel 316 (SS 316), polyvinyl chloride (PVC) and glass. The predictability of thermodynamic adhesion test methods was validated by comparison with 24-well microtiter plate assays using nine reference strains and three adhesion surfaces (SS 316, PVC and PE). Results for Acinetobacter calcoaceticus, Burkolderia cepacia and Stenotrophomonas maltophilia sp. 2 were congruent between both methods whilst they differed for the other bacteria to at least one material. Only A. calcoaceticus had strongly adherent properties to the three tested surfaces. Strain variation in adhesion ability was detected only for Sphingomonas capsulata. Analysis of adhesion demonstrated that in addition to physicochemical surface properties of bacterium and substratum, biological factors are involved in early adhesion processes, suggesting that reliance on thermodynamic approaches alone may not accurately predict adhesion capacity.European Commission Research Project SAFER; Portuguese Foundation for Science and Technology; University of Manchester

NaOCl effect on biofilm produced by Staphylococcus aureus isolated from the milking environment and mastitis infected cows

Biofilms constitute a physical barrier, protecting the encased bacteria from detergents and sanitizers. The objective of this work was to analyze the effectiveness of sodium hypochlorite (NaOCl) against strains of Staphylococcus aureus isolated from raw milk of cows with subclinical mastitis and Staphylococcus aureus isolated from the milking environment (blowers and milk conducting tubes). The results revealed that, in the presence of NaOCl (150ppm), the number of adhered cells of the twelve S. aureus strains was significantly reduced. When the same strains were evaluated in biofilm condition, different results were obtained. It was found that, after a contact period of five minutes with NaOCl (150ppm), four strains (two strains from milk , one from the blowers and one from a conductive rubber) were still able to grow. Although with the increasing contact time between the bacteria and the NaOCl (150ppm), no growth was detected for any of the strains. Concerning the efficiency of NaOCl on total biofilm biomass formation by each S. aureus strain, a decrease was observed when these strains were in contact with 150 ppm NaOCl for a total period of 10 minutes. This study highlights the importance of a correct sanitation protocol of all the milk processing units which can indeed significantly reduce the presence of microorganisms, leading to a decrease of cow´s mastitis and milk contamination.This study was supported by Portuguese Foundation for Science and Technology (FCT) through the grant SFRH/BPD/20987/2004 attributed to Cláudia Botelho and thanks to FAPESP (Fundação de Amparo a Pesquisa do Estado de São Paulo) for the scholarship attributed to Poliana de C. Melo

Measuring the orbit shrinkage rate of hot Jupiters due to tides

A tidal interaction between a star and a close-in exoplanet leads to shrinkage of the planetary orbit and eventual tidal disruption of the planet. Measuring the shrinkage of the orbits will allow for the tidal quality parameter of the star ($Q'_\star$) to be measured, which is an important parameter to obtain information about stellar interiors. We analyse data from TESS for two targets known to host close-in hot Jupiters, WASP-18 and WASP-19, to measure the current limits on orbital period variation and provide new constrains on $Q'_\star$. We modelled the transit shape using all the available TESS observations and fitted the individual transit times of each transit. We used previously published transit times together with our results to fit two models, a constant period model, and a quadratic orbital decay model, MCMC algorithms. We find period change rates of $(-0.11\pm0.21)\times10^{-10}$ for WASP-18b and $(-0.35\pm0.22)\times10^{-10}$ for WASP-19b and we do not find significant evidence of orbital decay in these targets. We obtain new lower limits for $Q'_\star$ of $(1.42\pm0.34)\times10^7$ in WASP-18 and $(1.26\pm0.10)\times10^6$ in WASP-19, corresponding to upper limits of the orbital decay rate of $-0.45\times10^{-10}$ and $-0.71\times10^{-10}$, respectively, with a 95% confidence level. We compare our results with other relevant targets for tidal decay studies. We find that the orbital decay rate in both WASP-18b and WASP-19b appears to be smaller than the measured orbital decay of WASP-12b. We show that the minimum value of $Q'_\star$ in WASP-18 is two orders of magnitude higher than that of WASP-12, while WASP-19 has a minimum value one order of magnitude higher, which is consistent with other similar targets. Further observations are required to constrain the orbital decay of WASP-18 and WASP-19.Comment: 10 pages plus 5-page appendix. To be published in Astronomy and Astrophysic