492 research outputs found
Chiral Surface Plasmon Polaritons on Metallic Nanowires
Chiral surface plasmon polaritons (SPPs) can be generated by linearly
polarized light incident at the end of a nanowire, exciting a coherent
superposition of three specific nanowire waveguide modes. Images of chiral SPPs
on individual nanowires obtained from quantum dot fluorescence excited by the
SPP evanescent field reveal the chirality predicted in our theoretical model.
The handedness and spatial extent of the helical periods of the chiral SPPs
depend on the input polarization angle and nanowire diameter as well as the
dielectric environment. Chirality is preserved in the free-space output wave,
making a metallic nanowire a broad bandwidth subwavelength source of circular
polarized photons.Comment: 4 figure
The value of “diaphragmatic relaxing incision” for the durability of the crural repair in patients with paraesophageal hernia: a double blind randomized clinical trial
BackgroundSurgical repair of paraesophageal hernias (PEHs) is burdened with high recurrence rates, and hitherto various techniques explored to enforce the traditional crural repair have not been successful. The hiatal reconstruction in PEH is exposed to significant tension, which may be minimized by adding a diaphragmatic relaxing incision to enhance the durability of the crural repair.Patients and methodsAll individuals undergoing elective laparoscopic repair of a large PEH, irrespective of age, were considered eligible. PEHs were classified into types II–IV. The preoperative work-up program included multidetector computed tomography and symptom assessment questionnaires, which will be repeated during the postoperative follow-up. Patients were randomly divided into a control group with crural repair alone and an intervention group with the addition of a left-sided diaphragmatic relaxing incision at the edge of the upper pole of the spleen. The diaphragmatic defect was then covered by a synthetic mesh.ResultsThe primary endpoint of this trial was the rate of anatomical PEH recurrence at 1 year. Secondary endpoints included symptomatic gastroesophageal reflux disease, dysphagia, odynophagia, gas bloat, regurgitation, chest pain, abdominal pain, nausea, vomiting, postprandial pain, cardiovascular and pulmonary symptoms, and patient satisfaction in the immediate postoperative course (3 months) and at 1 year. Postoperative complications, morbidity, and disease burden were recorded for each patient. This was a double-blind study, meaning that the operation report was filed in a locked archive to keep the patient, staff, and clinical assessors blinded to the study group allocation. Blinding must not be broken during the follow-up unless required by any emergencies in the clinical management of the patient. Likewise, the patients must not be informed about the details of the operation.Trial RegistrationClinicalTrials.gov, identification number NCT04179578
Sustainable Phosphorus Loadings from Effective and Cost-Effective Phosphorus Management Around the Baltic Sea
Nutrient over-enrichment of the Baltic Sea, accompanied by intensified algal blooms and decreasing water clarity, has aroused widespread concern in the surrounding countries during the last four decades. This work has used a well-tested dynamic mass-balance model to investigate which decrease in total phosphorus loading would be required to meet the environmental goal to restore the trophic state in the Baltic Sea to pre-1960s levels. Furthermore, the extent to which various abatement options may decrease the phosphorus loading in a cost-effective manner has been studied. Upgrading urban sewage treatment in the catchment could, alone or in combination with banning phosphates in detergents, be sufficient to meet the set environmental goal, at an estimated annual basin-wide cost of 0.21–0.43 billion euro. Such a plan would potentially decrease the total phosphorus loading to the Baltic Sea with 6,650–10,200 tonnes per year
Coupling of plasmonic nanoparticles to their environments in the context of van der Waals-Casimir interactions
We present experiments in which the interaction of a single gold nanoparticle
with glass substrates or with another gold particle can be tuned by in-situ
control of their separations using scanning probe technology. We record the
plasmon resonances of the coupled systems as a function of the polarization of
the incident field and the particle position. The distinct spectral changes of
the scattered light from the particle pair are in good agreement with the
outcome of finite difference time-domain (FDTD) calculations. We believe our
experimental technique holds promise for the investigation of the van der
Waals-Casimir type interactions between nanoscopic neutral bodies.Comment: 9 pages, 7 figure
An Operational Definition of a Statistically Meaningful Trend
Linear trend analysis of time series is standard procedure in many scientific disciplines. If the number of data is large, a trend may be statistically significant even if data are scattered far from the trend line. This study introduces and tests a quality criterion for time trends referred to as statistical meaningfulness, which is a stricter quality criterion for trends than high statistical significance. The time series is divided into intervals and interval mean values are calculated. Thereafter, r2 and p values are calculated from regressions concerning time and interval mean values. If r2≥0.65 at p≤0.05 in any of these regressions, then the trend is regarded as statistically meaningful. Out of ten investigated time series from different scientific disciplines, five displayed statistically meaningful trends. A Microsoft Excel application (add-in) was developed which can perform statistical meaningfulness tests and which may increase the operationality of the test. The presented method for distinguishing statistically meaningful trends should be reasonably uncomplicated for researchers with basic statistics skills and may thus be useful for determining which trends are worth analysing further, for instance with respect to causal factors. The method can also be used for determining which segments of a time trend may be particularly worthwhile to focus on
The importance of sedimenting organic matter, relative to oxygen and temperature, in structuring lake profundal macroinvertebrate assemblages
We quantified the role of a main food
resource, sedimenting organic matter (SOM), relative
to oxygen (DO) and temperature (TEMP) in structuring
profundal macroinvertebrate assemblages in
boreal lakes. SOM from 26 basins of 11 Finnish lakes
was analysed for quantity (sedimentation rates),
quality (C:N:P stoichiometry) and origin (carbon
stable isotopes, d13C). Hypolimnetic oxygen and
temperature were measured from each site during
summer stratification. Partial canonical correspondence
analysis (CCA) and partial regression analyses
were used to quantify contributions of SOM, DO and
TEMP to community composition and three macroinvertebrate
metrics. The results suggested a major
contribution of SOM in regulating the community
composition and total biomass. Oxygen best explained
the Shannon diversity, whereas TEMP had largest
contribution to the variation of Benthic Quality Index.
Community composition was most strongly related to d13C of SOM. Based on additional d13C and stoichiometric
analyses of chironomid taxa, marked differences
were apparent in their utilization of SOM and
body stoichiometry; taxa characteristic of oligotrophic
conditions exhibited higher C:N ratios and lower C:P
and N:P ratios compared to the species typical of
eutrophic lakes. The results highlight the role of SOM
in regulating benthic communities and the distributions
of individual species, particularly in oligotrophic
systems
How do MNC R&D laboratory roles affect employee international assignments?
Research and development (R&D) employees are important human resources for multinational corporations (MNCs) as they are the driving force behind the advancement of innovative ideas and products. International assignments of these employees can be a unique way to upgrade their expertise; allowing them to effectively recombine their unique human resources to progress existing knowledge and advance new ones. This study aims to investigate the effect of the roles of R&D laboratories in which these employees work on the international assignments they undertake. We categorise R&D laboratory roles into those of the support laboratory, the locally integrated laboratory and the internationally interdependent laboratory. Based on the theory of resource recombinations, we hypothesise that R&D employees in support laboratories are not likely to assume international assignments, whereas those in locally integrated and internationally interdependent laboratories are likely to assume international assignments. The empirical evidence, which draws from research conducted on 559 professionals in 66 MNC subsidiaries based in Greece, provides support to our hypotheses. The resource recombinations theory that extends the resource based view can effectively illuminate the international assignment field. Also, research may provide more emphasis on the close work context of R&D scientists rather than analyse their demographic characteristics, the latter being the focus of scholarly practice hitherto
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