Resonance between Noise and Delay

We propose here a stochastic binary element whose transition rate depends on its state at a fixed interval in the past. With this delayed stochastic transition this is one of the simplest dynamical models under the influence of ``noise'' and ``delay''. We demonstrate numerically and analytically that we can observe resonant phenomena between the oscillatory behavior due to noise and that due to delay.Comment: 4 pages, 5 figures, submitted to Phys.Rev.Lett Expanded and Added Reference

Large area quantum dot luminescent solar concentrators for use with dye-sensitised solar cells

Green-emitting quantum dot luminescent solar concentrators are used to sensitise an optically-matched dye-sensitised solar cell.</p

Beyond quantitative and qualitative traits: three telling cases in the life sciences

This paper challenges the common assumption that some phenotypic traits are quantitative while others are qualitative. The distinction between these two kinds of traits is widely influential in biological and biomedical research as well as in scientific education and communication. This is probably due to both historical and epistemological reasons. However, the quantitative/qualitative distinction involves a variety of simplifications on the genetic causes of phenotypic variability and on the development of complex traits. Here, I examine three cases from the life sciences that show inconsistencies in the distinction: Mendelian traits (dwarfism and pigmentation in plant and animal models), Mendelian diseases (phenylketonuria), and polygenic mental disorders (schizophrenia). I show that these traits can be framed both quantitatively and qualitatively depending, for instance, on the methods through which they are investigated and on specific epistemic purposes (e.g., clinical diagnosis versus causal explanation). This suggests that the received view of quantitative and qualitative traits has a limited heuristic power—limited to some local contexts or to the specific methodologies adopted. Throughout the paper, I provide directions for framing phenotypes beyond the quantitative/qualitative distinction. I conclude by pointing at the necessity of developing a principled characterisation of what phenotypic traits, in general, are

Research data supporting "Large Area Quantum Dot Luminescent Solar Concentrators for Use with Dye-Sensitised Solar Cells”

The folder “DSSC-IV test” contains the data for the current-voltage characteristics of the DSSC obtained following the illumination of either the champion LSC or a control device (undoped pLMA-co-EGDM slab) The folder “Extended optical absorption of QDs_fig 2 inset” contains the for the absorption profile of the quantum dots (QDs) with the observation window extended to 300 nm. The folder “IPCE spectra with LSC edge luminescence” contains the data for the edge emission for the champion LSC device and an undoped pLMA-co-EGDM slab and the IPCE spectrum of an N719 DSSC. All measurements performed under 1 sun illumination with an edge area of 0.4 × 0.3 cm2 for the LSCs. The folder “lifetimes” contain the data for the PL decay curves of CdSe@ZnS/ZnS QDs in hexane, the pLMA-co-EGDM matrix and the instrument response function. Emission and excitation wavelength were λem = 510 nm and λex = 458 nm, respectively. The folder “LSC Optical transmission” contains the optical image of a QD-loaded LSC under standard indoor lighting conditions. The folder “Optical power decay with distance” contains data for (a) optical power output (OPout) at the centre of a single edge (4.0 cm × 0.3 cm) as a function of distance of distance, d, from the illumination site under irradiation with solar simulated light (1 sun). The decrease in optical power observed with increasing d is due to the reabsorption of emitted photons. (b) optical power output under the same measurement conditions using guided 750 nm light. The optical power decreases but no red-shift with increasing d using this irradiation source. (c) Intensity normalised decay of the integrated optical power output as a function of d under 1 sun illumination and using 750 nm guided light, as well as the integrated optical power output corrected for scaterring losses. (d) Spectral profile of the 750 nm source used for the guided light experiments. The folder “optical stability” contains the data for the optical power output of the CdSe@ZnS/ZnS-LSC (35 mm × 20 mm) as a function of irradiation time (normalised to OPout at 0 h irradiation) under high UV intensity (366 nm, 5.01 Wm-2), to investigated the photodegradation of the LSC. The folder “photostability UV” contains the data for UV/Vis absorption spectra obtained after 0 h and 10 h of UV illumination (366, 5.01 Wm-2). The folder “solid state PL and abs comparisson with solution” contains the data for UV/Vis absorption and photoluminescence (PL) spectra (λex = 350 nm) of CdSe@ZnS/ZnS QDs dissolved in hexane and embedded in pLMA-co-EGDM film. The folder “TEM Histogram” contains the data for the histogram of the corresponding diameter of the nanoparticles as analysed by TEM using the ImageJ programme. The folder “TGA data” contains the data for thermogravimetric analysis of the QD-doped LMA-co-EGDM polymer composite

Preparation and investigation of quantum-dot-loaded hollow polymer microspheres

In this work, hollow poly(methyl methacrylate) (PMMA) microspheres loaded with CdSe/CdS core-shell quantum dots (QDs) were fabricated onto hydrophilic glass substrates using a spray-drying method. The PMMA microspheres were investigated using scanning electron microscopy, confocal microscopy, and fluorescent lifetime imaging microscopy (FLIM) to investigate the morphology of the spheres and confirm their hollow structure. The QDs were used as fluorophores in confocal microscopy to observe the central cavity of the microspheres and in solid-state photoluminescence spectroscopy to observe whispering gallery modes (WGMs), demonstrating the high optical quality of the hollow microspheres and their potential application as optical microresonators. © 2013 American Chemical Society.We thank Science Foundation Ireland (Grant SFI 07/IN.1/I1862), Trinity College Dublin, Higher Education Authority, and Ministry of Education and Science of the Russian Federation (Grant 14.B25.31.0002) for financial support.Peer Reviewe

Optical properties of hollow polymer microspheres loaded with semiconductor quantum dots

Trabajo presentado a la 16th International Conference on Transparent Optical Networks (ICTON), celebrada en Grazer Messe (Austria) del 6 al 10 de julio de 2014.In this paper, we report on fabrication and optical properties of hollow poly(methyl methacrylate) (PMMA) microspheres loaded with CdSe/CdS core-shell quantum dots. The PMMA microspheres were fabricated using a spray-drying method and investigated using scanning electron microscopy, confocal microscopy, and fluorescent lifetime imaging microscopy. Micro-photoluminescence studies of individual microspheres were also performed revealing pronounced whispering gallery modes. This result demonstrates the high optical quality of the hollow microspheres and their potential application as optical microresonatorsPeer Reviewe

Chiral nanoparticles in singular light fields

The studying of how twisted light interacts with chiral matter on the nanoscale is paramount for tackling the challenging task of optomechanical separation of nanoparticle enantiomers, whose solution can revolutionize the entire pharmaceutical industry. Here we calculate optical forces and torques exerted on chiral nanoparticles by Laguerre–Gaussian beams carrying a topological charge. We show that regardless of the beam polarization, the nanoparticles are exposed to both chiral and achiral forces with nonzero reactive and dissipative components. Longitudinally polarized beams are found to produce chirality densities that can be 10(9) times higher than those of transversely polarized beams and that are comparable to the chirality densities of beams polarized circularly. Our results and analytical expressions prove useful in designing new strategies for mechanical separation of chiral nanoobjects with the help of highly focussed beams