Dark interlayer plasmons in colloidal gold nanoparticle bi- and few-layers

We demonstrate the excitation of dark plasmon modes with linearly polarized light at normal incidence in self-assembled layers of gold nanoparticles. Because of field retardation, the incident light field induces plasmonic dipoles that are parallel within each layer but antiparallel between the layers, resulting in a vanishing net dipole moment. Using microabsorbance spectroscopy we measured a pronounced absorbance peak and reflectance dip at 1.5 eV for bi- and trilayers of gold nanoparticles with a diameter of 46 nm and 2 nm interparticle gap size. The excitations were identified as dark interlayer plasmons by finite-difference time-domain simulations. The dark plasmon modes are predicted to evolve into standing waves when further increasing the layer number, which leads to 90% transmittance of the incident light through the nanoparticle film. Our approach is easy to implement and paves the way for large-area coatings with tunable plasmon resonance

Bifenthrin Baseline Susceptibility and Evaluation of Simulated Aerial Applications in \u3ci\u3eStriacosta albicosta\u3c/i\u3e (Lepidoptera: Noctuidae)

Striacosta albicosta (Smith) is a maize pest that has recently expanded its geographical range into the eastern United States and southeastern Canada. Aerial application of pyrethroids, such as bifenthrin, has been a major practice adopted to manage this pest. Reports of field failure of pyrethroids have increased since 2013. Striacosta albicosta populations were collected in 2016 and 2017 from maize fields in Nebraska, Kansas, and Canada and screened with bifenthrin active ingredient in larval contact dose-response bioassays. Resistance ratios estimated were generally low in 2016 (1.04- to 1.32-fold) with the highest LC50 in North Platte, NE (66.10 ng/cm2) and lowest in Scottsbluff, NE (50.10 ng/cm2). In 2017, O’Neill, NE showed the highest LC50 (100.66 ng/cm2) and Delhi, Canada exhibited the lowest (6.33 ng/cm2), resulting in a resistance ratio variation of 6.02- to 15.90-fold. Implications of bifenthrin resistance levels were further investigated by aerial application simulations. Experiments were conducted with a spray chamber where representative S. albicosta populations were exposed to labeled rates of a commercial bifenthrin formulation. Experiments resulted in 100% mortality for all populations, instars, insecticide rates, and carrier volumes, suggesting that levels of resistance estimated for bifenthrin active ingredient did not seem to impact the efficacy of the correspondent commercial product under controlled conditions. Results obtained from this research indicate that control failures reported in Nebraska could be associated with factors other than insecticide resistance, such as issues with the application technique, environmental conditions during and/or after application, or the insect’s natural behavior. Data generated will assist future S. albicosta resistance management programs

Implementation of lean in health care environments: an update of systematic reviews

Purpose – Even though the implementation of Lean in healthcare environments is relatively recent, it has been receiving a lot of attention in recent years. Partly due to the fact that it is a recent field of practice and research and partly because the number of works developed in this field has grown rapidly, it is important to frequently update the perspectives on this field of investigation. Thus, this article aims to systematically review the implementation of Lean tools and techniques applied to hospital organizational areas in a 5-year period, between 2014 to 2018, complementing some of the most relevant reviews already published. The most important criteria such as tools, methods and principles, hospital areas intervened, improvements and difficulties were assessed and quantified. Methodology - As starting point for this systematic literature review, a set of selected pre-existing review publications was used to support the current work and as the ground base for the expansion of the studies about Lean Healthcare. The current study contemplated 114 articles from a 5-year period between 2014 and 2018. A subset of 58 of these articles was critically assessed to understand the application of lean tools and methods in different hospital areas. Findings - The thorough analysis of selected articles show a lack of works in Continuous Improvement approaches when compared to the application of work organization, visual management, and diagnosing and problem-solving tools. The reported improvement results demonstrate alignment with the principles and foundations of lean philosophy, but such results are presented in isolated initiatives and without robust evidence of long-term maintenance. Moreover, this study shows an evolution in the number of articles referring to lean implementation in hospital areas, but in its great majority, such articles report isolated implementations in different areas, not spreading those for the global organization. Thus, some of the main recommendations, are the need to implement studies on complete flows of patients, drugs and materials, instead of isolated initiatives, and strive to promote cultural change of hospitals through structural changes, following new visions and strategic objectives, supported by real models of continuous structural and sustained improvement. Originality – The current work develops a new perspective of the articles published under the thematic of Lean Healthcare, published in a recent period of 5 years, which are not completely covered by other works. Additionally, it explicitly applied, in an innovative way, an approach that used a set of previous reviews as the starting point for this SLR. In this way, it integrates approaches and categories from different SLRs, creating a framework of analysis that can be used by future researchers. Finally, it shows the most recent implementations of Lean Healthcare, exposing the current trends, improvements and also the main gaps.This work has been supported by FCT–Fundação para a Ciência e Tecnologia within the R&D Units Project Scope UIDB/00319/2020 and project POCI-01-0145-FEDER-03029

A systematized approach for reduction of medical appointment waiting list

Paper aims: This work aims to develop a systematized approach for the reduction of medical appointment waiting lists, proposing an optimization decision-making model followed by continuous people engagement towards a systematic approach for waiting list problem-solving. Originality: There are several studies related to waiting lists in healthcare contexts, however, the present study presents an innovative approach for waiting list problem-solving by proposing prescriptive decision-making models followed by continuous improvement and people engagement. Research method: A research approach with the following phases was developed: system analysis, problem quantification, and development of an optimization model. After these phases, the model was applied, and the results were analysed, as contributions to a systematized model. Main findings: The model was applied to the screening waiting list for orthopaedics appointments followed by the fundamental involvement of medical doctors, which made it possible to implement the optimal solution generated by the model, resulting in a reduction of 90% by 56 days in waiting time for the screening process. Implications for theory and practice: This model contributes for theory and for practice as a way to deal with different scenarios for waiting list reduction in the upcoming days during and after the pandemic.This work was supported by projects UIDB/00319/2020 and POCI-01-0145-FEDER-030299, from Fundação para a Ciência e Tecnologia (FCT), Portugal

Chemistry of volcanic soils used for agriculture in Brava Island (Cape Verde) envisaging a sustainable management

In order to acquire a better knowledge of iron forms, clay minerals and the content and distribution of trace elements in soils mostly used for agriculture in the semi-arid Brava Island (Cape Verde), iron speciation, mineralogy and chemical contents in the clay-size fraction (<2 μm) of incipient soils developed on sediments and phonolitic pyroclasts was performed by Mössbauer spectroscopy, X-ray diffraction and neutron activation analysis. In contrast with the whole samples in the clay-size fraction of all the studied soils only Fe(III) was detected. Iron and chromium are depleted suggesting their occurrence as ferromagnesian and oxide minerals present in coarser particles. Rare earth elements are concentrated in the clay-size fraction, and significant differences are found in their distribution which may be partially due to oxidation, since Ce anomalies were observed. Among the other chemical elements studied, high concentrations of arsenic, bromine, and particularly antimony were found in the clay-size fraction of soils where all the Fe oxides are nano-sized, confirming the predominant adsorption of these elements on the nano-particles surface. The existence of significant amounts of these elements as well as of vitreous phases in fine particles of these soils may contribute to their mobility and accumulation in groundwater and in plants, both by absorption and by dust deposition onto the plant leaves.publishe

Optimization model for waiting list management and service continuous improvement

Purpose - This study aims to assess the number of hours*doctor required per day in each week, in a time horizon of 52 weeks, so that it is possible to gradually and controllably reduce the waiting list and the response time for the triage process that precedes the scheduling of an hospital appointment of orthopaedics speciality. A national decree law requires a response time equal or less than 5 days for the triage process, but currently, in the hospital under study, with a waiting list of 1244 users, the response time is, on average, 66 days for the speciality of orthopaedics. Design / methodology / approach - With a team of orthopaedists (constituted with the objective of improving access to orthopaedics speciality appointments), the current status of the waiting list was analysed and possibilities for improvement were discussed. Based on the professional's expertise, several parameters were defined as the more relevant to manage the waiting list for the triage process, allowing the development of an optimization model which aims to minimize the number of hours*doctor per day per week required to achieve the defined objectives. Findings - The model is able to define an optimal number of hours*doctor per day per week meeting all the process constraints. Thus, it is required 1400 hours*doctor to reduce and maintain the waiting list between the boundaries defined as acceptable, as well as reduce the waiting time to 9 days. The model is also capable of orienting the professionals to search alternative optimal solutions that for specific contexts may better fill the hospital needs. Originality / value - This study presents a tool that can support waiting lists management across any service provided by health organizations. The model ease of use allows for fast parameterization and results achievement in continuous improvement meetings.The authors would like to thank to the hospital administration and health professional that collaborated with the research team during this work. This work has been supported by FCT – Fundação para a Ciência e Tecnologia within the Projects UIDB/00319/2020 and POCI-01-0145-FEDER-030299

Fermi-Energy-Dependent Structural Deformation of Chiral Single-Wall Carbon Nanotubes

In this work, we use an extended tight-binding approach for calculating the Fermi-energy dependence of the structural deformation of chiral single-wall carbon nanotubes (SWNTs). We show that, in general, nanotube strains occur in such a way as to avoid a net charge from being accumulated on the nanotube. We also investigate the effect of the Fermi-energy-induced strains on the electronic structure of SWNTs, showing that the optical transition energies change by up to 0.5 eV due to the induced strains and that this change is nearly independent of how the nanotube is deformed. Finally, we also consider the contribution of the electron-electron Coulomb repulsion to the total energy by using an effective regularized potential energy model. We show that the inclusion of the Coulomb repulsion leads to larger strains and smaller net charges transferred to the nanotube.National Science Foundation (U.S.) (Grant DMR-1004147

Direct optical excitation of dark plasmons for hot electron generation

An ideal plasmonic system for hot-electron generation allows the optical excitation of plasmons, limits radiation losses, exhibits strong non-radiative electron damping, and is made from scalable and cost-effective materials. Here we demonstrate the optical excitation of dark interlayer plasmons in bilayers of colloidal gold nanoparticles. This excitation is created by an antiparallel orientation of the dipole moments in the nanoparticle layers; it is expected to exhibit strongly reduced radiative damping. Despite the vanishing dipole moment, an incoming electromagnetic wave that is propagating normal to the surface will excite the dark mode due to field retardation. We observe a strong peak in the absorption spectrum of a colloidal gold bilayer (nanoparticle diameter = 46 nm); this peak is absent for a nanoparticle monolayer. The full width at half maximum of the dark mode is 230 meV for an ideal nanoparticle crystal and 320 meV for the structure produced by self-assembly out of solution. The position and width of the dark plasmon are efficiently tailored by the interparticle distance within the layer, nanoparticle size and layer number. We present time-resolved pump and probe experiments of hot-electron generation by bright and dark bilayer nanoparticle modes

Microbial water quality of public swimming pool in the district of Bragança

The poor water quality of recreational and rehabilitation pools,has been correlated to insufficient disinfection or human contamination, and can be a vehicle for transmitting diseasesto users. Because people with different characteristics attendpublic swimming pools with different purposes, the pool water quality control is essential to minimize hazards related tounsafe water.MethodsThis study was based on data collection of 144 samples between 2018 and 2020 in therapeutic and recreational pools(indoor and outdoor) in the Braganca district. The proportionof the number of bathers were estimated, as well as the microbial parameters: Total coliforms,Escherichia coli, enterococci, Pseudomonas aeruginosa, total Staphylococcus,Staphylococcus coagulase-positive and mesophilic microbial count. Results: The E. coli, enterococci and mesophilic microbial count werenot found in any sample. Unsafe pool water was mainly contaminated by both photogenicP. aeruginosa(6.3%) and total Sthaphylococcus (10.4%). Levels ofP. aeruginosaintherapeutic pools was greater than in recreational pools (indoor and outdoor) (10.5% vs 6.8% and 4.5%, respectively),while total Sthaphylococcus was absent in therapeutic pools and represent 13.6% and 10.6% of positivity in indoor and outdoors wimming pools, respectively. The bathers number medium of therapeutic, indoor and outdoor pools was 4.8, 3.4 and 6.9,respectively. Conclusions: Overall, the results endorse the good water quality of theseswimming pools, mainly by the absent of faecally-derivedbacteria. The presence of P. aeruginosain therapeutic pools canbe explained by the type of users, while the high number of bathers may promote the growth of some microorganisms,particularly in outdoor poolsinfo:eu-repo/semantics/publishedVersio