Optical sensing with Anderson-localised light

We show that fabrication imperfections in silicon nitride photonic crystal waveguides can be used as a resource to efficiently confine light in the Anderson-localised regime and add functionalities to photonic devices. Our results prove that disorder-induced localisation of light can be utilised to realise an alternative class of high-quality optical sensors operating at room temperature. We measure wavelength shifts of optical resonances as large as 15.2 nm, more than 100 times the spectral linewidth of 0.15\,nm, for a refractive index change of about 0.38. By studying the temperature dependence of the optical properties of the system, we report wavelength shifts of up to about 2 nm and increases of more than a factor 2 in the quality factor of the cavity resonances, when going from room to cryogenic temperatures. Such a device can allow simultaneous sensing of both local contaminants and temperature variations, monitored by tens of optical resonances spontaneously appearing along a single photonic crystal waveguide. Our findings demonstrate the potential of Anderson-localised light in photonic crystals for scalable and efficient optical sensors operating in the visible and near-infrared range of wavelengths.Comment: 10 pages, 3 figure

Method to Identify Change based on Content-based Embedding

A method for identifying change based on content-based embedding is disclosed. The proposed method computes content similarity of content items uploaded to a user’s personal channel. The method then computes a channel risk score, which identifies whether the type(s) of content uploaded to a user’s personal channel has changed after a specific point in time. A channel in which the type(s) of content has changed after a specific point in time, for example after the channel was reviewed for a monetization program, may indicate potential abuse of the monetization program. Based on the risk score, the method may flag potentially abusive channels for administrative review, which may be reviewed by an automated system, a human reviewer, or a combination

Overcoming process blindness in the design of an online unit

Learning environment research can contribute to our understanding of how psychosocial processes need to be balanced with cognitive outcomes in the design of units of study. The research on Web-based learning supports the assumption that the nature of social interaction affects student outcomes and student perceptions of the quality of the learning experience. The purposeful this study is to examine student perceptions of psychosocial processes in a blended learning environment using a learning environment survey tool. Students assessed the environments as favourable, but found that the quality of dialogue and peer support offered did not meet their needs. Implications for online design are considered

Feasibility study of novel crew wellbeing and alternative countermeasures solutions for recreational spaces in future Lunar permanent settlements

With the successful conclusion of the mission Artemis I, a new era of space exploration has started with the aim to pave the way for humans to return to the Moon. It is therefore of paramount importance to develop proper solutions for permanent outposts, with a special focus on habitability, ergonomics, and long-term usability in hypogravity environments such as the lunar environment. By focusing on crew psychophysiological wellbeing, this work revolves around the conception of spaces for the practice of new fitness and leisure activities as countermeasure against stress in long-term mission. It is well known that by introducing game components into exercise routines psychological and physiological wellbeing can be significantly improved, resulting in the enhancement of crew’s performance. Thus, the present study investigates how tennis, which has many proven health benefits, could theoretically be played under lunar gravity conditions focusing on how this game would change due to the lunar environmental factors in terms of regulation and equipment. A qualitative assessment is conducted through a comparative evaluation of the features of racket-ball sports practised on the Earth, to better adapt rules and playing of tennis to lunar conditions. Furthermore, the investigation addresses the study of the technical feasibility of a lunar tennis facility, in order to provide lunar settlements design with new elements to enhance habitability in long-duration human missions on the Moon

Discreteness without symmetry breaking: a theorem

This paper concerns sprinklings into Minkowski space (Poisson processes). It proves that there exists no equivariant measurable map from sprinklings to spacetime directions (even locally). Therefore, if a discrete structure is associated to a sprinkling in an intrinsic manner, then the structure will not pick out a preferred frame, locally or globally. This implies that the discreteness of a sprinkled causal set will not give rise to ``Lorentz breaking'' effects like modified dispersion relations. Another consequence is that there is no way to associate a finite-valency graph to a sprinkling consistently with Lorentz invariance.Comment: 7 pages, laTe

Honey Environmental DNA Can Be Used to Detect and Monitor Honey Bee Pests: Development of Methods Useful to Identify Aethina tumida and Galleria mellonella Infestations

Environmental DNA (eDNA) contained in honey derives from the organisms that directly and indirectly have been involved in the production process of this matrix and that have played a role in the hive ecosystems where the honey has been produced. In this study we set up PCR-based assays to detect the presence of DNA traces left in the honey by two damaging honey bee pests: the small hive beetle (Aethina tumida) and the greater wax moth (Galleria mellonella). DNA was extracted from 82 honey samples produced in Italy and amplified using two specific primer pairs that target the mitochondrial gene cytochrome oxidase I (COI) of A. tumida and two specific primer pairs that target the same gene in G. mellonella. The limit of detection was tested using sequential dilutions of the pest DNA. Only one honey sample produced in Calabria was positive for A. tumida whereas about 66% of all samples were positively amplified for G. mellonella. The use of honey eDNA could be important to establish early and effective measures to contain at the local (e.g., apiary) or regional scales these two damaging pests and, particularly for the small hive beetle, to prevent its widespread diffusion

Partitioning of amino acids in the novel biphasic systems based on environmentally friendly ethyl lactate

For the first time, we report on the performance of biphasic system composed of ethyl lactate, water and inorganic salt (K3PO4, K2HPO4 and K2CO3) for the separation of amino acids (L-phenylalanine, L-tryptophan and L-tyrosine) from their aqueous solutions. Cloud points (solubility curve) and tie-lines for three ternary (ethyl la ctate + water + inorganic salt) systems at 298.2 K and 313.2 K at atmospheric pressure were determined. For certain composition range, these mixture exhibit biphasic systems – top and bottom phases rich in ethyl lactate and salt, respectively. Partition coefficients of amino acids and their extraction efficiencies, as essential parameters for design of any separation process, were measured at two temperatures – 298.2 K and 313.2 K. The maximum values of partition coefficients were observed for the system containing K3PO4: 3.5, 3.7 and 11.9 for L-phenylalanine at 313.2 K, L-tyrosine at 298.2 K and L-tryptophan at 313.2 K, respectively. The obtained results clearly showed that the biphasic systems based on ethyl lactate are suitable for the efficient and sustainable recovery of amino acids from solutions with water

GaAs droplet quantum dots with nanometer-thin capping layer for plasmonic applications

We report on the growth and optical characterisation of droplet GaAs quantum dots with extremely-thin (11 nm) capping layers. To achieve such result, an internal thermal heating step is introduced during the growth and its role in the morphological properties of the quantum dots obtained is investigated via scanning electron and atomic force microscopy. Photoluminescence measurements at cryogenic temperatures show optically stable, sharp and bright emission from single quantum dots, at near-infrared wavelengths. Given the quality of their optical properties and the proximity to the surface, such emitters are ideal candidates for the investigation of near field effects, like the coupling to plasmonic modes, in order to strongly control the directionality of the emission and/or the spontaneous emission rate, crucial parameters for quantum photonic applications.Comment: 1 pages, 3 figure