2,227 research outputs found
Competence development and affective commitment as mechanisms that explain the relationship between organizational culture and turnover intentions
This study investigated the effect of organizational culture (supportive culture, innovation culture, goal culture and rule culture) on turnover intentions and whether this relationship was mediated by organizational practices of competencies development (training, functional rotation and individualized support) and affective commitment. The study sample consisted of 369 participants working in organizations based in Portugal. The results show that only goal culture positively and significantly affects the three dimensions of organizational practices of development competencies and affective commitment. The culture of support has a positive and significant effect on functional rotation, individualized support and affective commitment. The culture of innovation has a positive and significant effect on training. Supportive culture, goal culture and the dimensions of organizational practices of development competencies negatively and significantly affect exit intentions. The serial mediating effect of organizational practices of development competencies and affective commitment on the relationship between organizational culture (supportive culture and goal culture) and turnover intentions was proven. Organizational culture, especially supportive culture and goal culture, proved to be relevant in boosting the implementation of organizational practices of development competencies, boosting affective commitment and reducing turnover intentions.info:eu-repo/semantics/publishedVersio
Microfluidics in gas sensing and artificial olfaction
SCENT-ERC-2014-STG-639123 (2015-2020) UIDB/04378/2020 PTDC/BII-BIO/28878/2017Rapid, real-time, and non-invasive identification of volatile organic compounds (VOCs) and gases is an increasingly relevant field, with applications in areas such as healthcare, agriculture, or industry. Ideal characteristics of VOC and gas sensing devices used for artificial olfaction include portability and affordability, low power consumption, fast response, high selectivity, and sensitivity. Microfluidics meets all these requirements and allows for in situ operation and small sample amounts, providing many advantages compared to conventional methods using sophisticated apparatus such as gas chromatography and mass spectrometry. This review covers the work accomplished so far regarding microfluidic devices for gas sensing and artificial olfaction. Systems utilizing electrical and optical transduction, as well as several system designs engineered throughout the years are summarized, and future perspectives in the field are discussed.publishersversionpublishe
Enhancing plant diversity in secondary forests
Dispersal, recruitment and establishment limitations are crucial processes shaping forest composition. In secondary forests these mechanisms may operate differently than in mature forests, because young and isolated secondary forests may suffer stronger limitations due to a lack of suitable dispersers and harsh environmental conditions— such as the elevated competition of exotic grasses. To assess establishment limitations in these forests, we undertook transplant experiments involving seeds and seedlings along a chronosequence of secondary forests in tropical Australia. The experiments included six species that varied in seed size (6–50 mm in length) and successional status (early to late successional). Seeds of five species were placed in one of three treatments: (1) exposed seeds, (2) fenced seeds, and (3) buried seeds, and multiple seedlings of six species were transplanted in block treatments. After 14–17 months, seed from all plant species germinated across all ages of secondary forests. However, in young secondary forest sites (4–12 years) fewer germinated seeds survived. The highest survival rates were observed for buried seeds (27.2%) compared to the low
survival of exposed seeds (6.0%). Planted seedlings (6 spp) had the greatest overall survival (63.1%) and the highest growth rates in older secondary forests. We found that
species identity was important for growth and survival in both experiments, but detected no effect of successional status or seed size. A crucial finding of this study was that the buried seeds of all species germinated and had relatively high survival irrespective of variation in site conditions or successional status, suggesting that seed availability may be a greater barrier to recovery of secondary forests in the region than the establishment limitations imposed by environmental conditions
Stable and oriented liquid crystal droplets stabilized by imidazolium ionic liquids
SCENT-ERC-2014-STG-639123(2015-2022) UIDP/04378/2020 UIDB/04378/2020 LA/P/0140/2020Liquid crystals represent a fascinating intermediate state of matter, with dynamic yet or-ganized molecular features and untapped opportunities in sensing. Several works report the use of liquid crystal droplets formed by microfluidics and stabilized by surfactants such as sodium do-decyl sulfate (SDS). In this work, we explore, for the first time, the potential of surface-active ionic liquids of the imidazolium family as surfactants to generate in high yield, stable and oriented liquid crystal droplets. Our results show that [C12MIM][Cl], in particular, yields stable, uniform and mon-odisperse droplets (diameter 74 ± 6 µm; PDI = 8%) with the liquid crystal in a radial configuration, even when compared with the standard SDS surfactant. These findings reveal an additional application for ionic liquids in the field of soft matter.publishersversionpublishe
Impact of the Cationic Moiety of Ionic Liquids on Chemoselective Artificial Olfaction
Funding Information: This research was funded by the European Research Council (ERC) under the EU Horizon 2020 research and innovation program [grant reference SCENT-ERC-2014-STG-639123, 2015–2022, and Grant Agreement No. 101069405─ENSURE─ERC-2022-POC1] and by national funds from FCT-Fundação para a Ciência e a Tecnologia, I.P., for projects PTDC/BII-BIO/28878/2017, PTDC/CTM-CTM/3389/2021, UIDP/04378/2020, and UIDB/04378/2020 of the Research Unit on Applied Molecular Biosciences-UCIBIO and the project LA/P/0140/2020 of the Associate Laboratory Institute for Health and Bioeconomy-i4HB. The authors thank FCT/MCTES for the PhD grant SFRH/BD/128687/2017. Publisher Copyright: © 2023 The Authors. Published by American Chemical Society.Ionogels and derived materials are assemblies of polymers and ionic liquids characterized by high stability and ionic conductivity, making them interesting choices as gas sensors. In this work, we assessed the effect of the ionic liquid moiety to generate ionogels and hybrid gels as electrical and optical gas sensors. Six ionic liquids consisting of a constant anion (chloride) and distinct cationic head groups were used to generate ionogels and hybrid gels and further tested as gas sensors in customized electronic nose devices. In general, ionogel-based sensors yielded higher classification accuracies of standard volatile organic compounds when compared to hybrid material-based sensors. In addition, the high chemical diversity of ionic liquids is further translated to a high functional diversity in analyte molecular recognition and sensing.publishersversionpublishe
Ionogels based on a single ionic liquid for electronic nose application
165186/2015-1 307501/2019-1 424027/2018-6 grant reference SCENT-ERC-2014-STG-639123 (2015-2020) UIDB/04378/2020 POCI-01-0145-FEDER-007728Ionogel are versatile materials, as they present the electrical properties of ionic liquids and also dimensional stability, since they are trapped in a solid matrix, allowing application in electronic devices such as gas sensors and electronic noses. In this work, ionogels were designed to act as a sensitive layer for the detection of volatiles in a custom-made electronic nose. Ionogels composed of gelatin and a single imidazolium ionic liquid were doped with bare and functionalized iron oxide nanoparticles, producing ionogels with adjustable target selectivity. After exposing an array of four ionogels to 12 distinct volatile organic compounds, the collected signals were analyzed by principal component analysis (PCA) and by several supervised classification methods, in order to assess the ability of the electronic nose to distinguish different volatiles, which showed accuracy above 98%.publishersversionpublishe
Deriving water quality parameters using sentinel-2 imagery: A case study in the Sado Estuary, Portugal
Monitoring water quality parameters and their ecological effects in transitional waters is usually performed through in situ sampling programs. These are expensive and time-consuming, and often do not represent the total area of interest. Remote sensing techniques offer enormous advantages by providing cost-effective systematic observations of a large water system. This study evaluates the potential of water quality monitoring using Sentinel-2 observations for the period 2018-2020 for the Sado estuary (Portugal), through an algorithm intercomparison exercise and time-series analysis of different water quality parameters (i.e., colored dissolved organic matter (CDOM), chlorophyll-a (Chl-a), suspended particulate matter (SPM), and turbidity). Results suggest that Sentinel-2 is useful for monitoring these parameters in a highly dynamic system, however, with challenges in retrieving accurate data for some of the variables, such as Chl-a. Spatio-temporal variability results were consistent with historical data, presenting the highest values of CDOM, Chl-a, SPM and turbidity during Spring and Summer. This work is the first study providing annual and seasonal coverage with high spatial resolution (10 m) for the Sado estuary, being a key contribution for the definition of effective monitoring programs. Moreover, the potential of remote sensing methodologies for continuous water quality monitoring in transitional systems under the scope of the European Water Framework Directive is briefly discussed.Fil: Sent, Giulia. Universidade Nova de Lisboa; PortugalFil: Biguino, Beatriz. Universidade Nova de Lisboa; PortugalFil: Favareto, Luciane. Universidade Nova de Lisboa; PortugalFil: Cruz, Joana. Universidade Nova de Lisboa; PortugalFil: Sá, Carolina. Universidade Nova de Lisboa; PortugalFil: Dogliotti, Ana Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Palma, Carla. Instituto Hidrográfico; PortugalFil: Brotas, Vanda. Universidade Nova de Lisboa; PortugalFil: Brito, Ana C.. Universidade Nova de Lisboa; Portuga
Virtual Screening of Plant Volatile Compounds Reveals a High Affinity of Hylamorpha elegans (Coleoptera: Scarabaeidae) Odorant-Binding Proteins for Sesquiterpenes From Its Native Host
Indexación: Web of ScienceHylamorpha elegans (Burmeister) is a native Chilean scarab beetle considered to be a relevant agricultural pest to pasture and cereal and small fruit crops. Because of their cryptic habits, control with conventional methods is difficult; therefore, alternative and environmentally friendly control strategies are highly desirable. The study of proteins that participate in the recognition of odorants, such as odorant-binding proteins (OBPs), offers interesting opportunities to identify new compounds with the potential to modify pest behavior and computational screening of compounds, which is commonly used in drug discovery, may help to accelerate the discovery of new semiochemicals. Here, we report the discovery of four OBPs in H. elegans as well as six new volatiles released by its native host Nothofagus obliqua (Mirbel). Molecular docking performed between OBPs and new and previously reported volatiles from N. obliqua revealed the best binding energy values for sesquiterpenic compounds. Despite remarkable divergence at the amino acid level, three of the four OBPs evaluated exhibited the best interaction energy for the same ligands. Molecular dynamics investigation reinforced the importance of sesquiterpenes, showing that hydrophobic residues of the OBPs interacted most frequently with the tested ligands, and binding free energy calculations demonstrated van der Waals and hydrophobic interactions to be the most important. Altogether, the results suggest that sesquiterpenes are interesting candidates for in vitro and in vivo assays to assess their potential application in pest management strategies.http://jinsectscience.oxfordjournals.org/content/16/1/3
Optical gas sensing with liquid crystal droplets and convolutional neural networks
UIDB/50009/2020 UIDB/ 04378/2020 SCENT-ERC-2014-STG-639123, 2015-2022Liquid crystal (LC)-based materials are promising platforms to develop rapid, miniaturised and low-cost gas sensor devices. In hybrid gel films containing LC droplets, characteristic optical texture variations are observed due to orientational transitions of LC molecules in the presence of distinct volatile organic compounds (VOC). Here, we investigate the use of deep convolutional neural networks (CNN) as pattern recognition systems to analyse optical textures dynamics in LC droplets exposed to a set of different VOCs. LC droplets responses to VOCs were video recorded under polarised optical microscopy (POM). CNNs were then used to extract features from the responses and, in separate tasks, to recognise and quantify the vapours exposed to the films. The impact of droplet diameter on the results was also analysed. With our classification models, we show that a single individual droplet can recognise 11 VOCs with small structural and functional differences (F1-score above 93%). The optical texture variation pattern of a droplet also reflects VOC concentration changes, as suggested by applying a regression model to acetone at 0.9–4.0% (v/v) (mean absolute errors below 0.25% (v/v)). The CNN-based methodology is thus a promising approach for VOC sensing using responses from individual LC-droplets.publishersversionpublishe
Why are tropical conifers disadvantaged in fertile soils? Comparison of Podocarpus guatemalensis with an angiosperm pioneer, Ficus insipida
Conifers are, for the most part, competitively excluded from tropical rainforests by angiosperms. Where they do occur, conifers often occupy sites that are relatively infertile. To gain insight into the physiological mechanisms by which angiosperms outcompete conifers in more productive sites, we grew seedlings of a tropical conifer (Podocarpus guatemalensis Standley) and an angiosperm pioneer (Ficus insipida Willd.) with and without added nutrients, supplied in the form of a slow-release fertilizer. At the conclusion of the experiment, the dry mass of P. guatemalensis seedlings in fertilized soil was approximately twofold larger than that of seedlings in unfertilized soil; on the other hand, the dry mass of F. insipida seedlings in fertilized soil was similar to 20-fold larger than seedlings in unfertilized soil. The higher relative growth rate of F. insipida was associated with a larger leaf area ratio and a higher photosynthetic rate per unit leaf area. Higher overall photosynthetic rates in F. insipida were associated with an approximately fivefold larger stomatal conductance than in P. guatemalensis. We surmise that a higher whole-plant hydraulic conductance in the vessel bearing angiosperm F. insipida enabled higher leaf area ratio and higher stomatal conductance per unit leaf area than in the tracheid bearing P. guatemalensis, which enabled F. insipida to capitalize on increased photosynthetic capacity driven by higher nitrogen availability in fertilized soil
- …