Clock Synchronization based on Second-Order Quantum Coherence of Entangled Photons

We present an algorithm for synchronizing two clocks based on second-order quantum interference between entangled photons generated by parametric down-conversion. The procedure is distinct from the standard Einstein two-way clock synchronization method in that photon correlations are used to define simultaneous events in the frame of reference of a Hong-Ou-Mandel (HOM) interferometer. Once the HOM interferometer is balanced, by use of an adjustable optical delay in one arm, arrival times of simultaneously generated photons are recorded by each clock. Classical information on the arrival times is sent from one clock to the other, and a correlation of arrival times is done to determine the clock offset.Comment: 5 pages, 2 figures. ReVTeX

Modelling the injured spinal cord using 3-dimensional cell cultures; strategies for improving tissue engineered repair

Abstract not available

Predicting individual susceptibility to Visually Induced Motion Sickness (VIMS) by Questionnaire

BACKGROUND The introduction of new visual technologies increases the risk of visually induced motion sickness (VIMS). The aim was to evaluate the 6-item Visually Induced Motion Sickness Susceptibility Questionnaire (VIMSSQ; also known as the VIMSSQ-short) and other predictors for individual susceptibility to VIMS. METHODS Healthy participants (10M+20F), mean age 22.9 (SD 5.0) years, viewed a 360° panoramic city scene projected in the visual equivalent to the situation of rotating about an axis tilted from the vertical. The scene rotated at 0.2Hz (72° s-1), with a ‘wobble’ produced by superimposed 18° tilt on the rotational axis, with a field of view of 83.5°. Exposure was 10 min or until moderate nausea was reported. Simulator Sickness Questionnaire (SSQ) was the index of VIMS. Predictors/correlates were VIMSSQ, Motion Sickness Susceptibility Questionnaire (MSSQ), Migraine (scale), Syncope, Social & Work Impact of Dizziness (SWID), Sleep quality/disturbance, Personality (‘Big Five’ TIPI), a prior multisensory Stepping-Vection test, and Vection during exposure. RESULTS The VIMSSQ had good scale reliability (Cronbach’s alpha=0.84). and correlated significantly with the SSQ (r=0.58). Higher MSSQ, Migraine, Syncope & SWID also correlated significantly with SSQ. Other variables had no significant relationships with SSQ. Regression models showed that the VIMSSQ predicted 34% of the individual variation of VIMS, increasing to 56% as MSSQ, Migraine, Syncope and SWID were incorporated as additional predictors. CONCLUSIONS The VIMSSQ is a useful adjunct to the MSSQ in predicting VIMS. Other predictors included Migraine, Syncope & SWID. No significant relationship was observed between Vection and VIMS

Measuring the susceptibility to visually induced motion sickness and its relationship with vertigo, dizziness, migraine, syncope and personality traits

BACKGROUND: The widespread use of visual technologies such as Virtual Reality increases the risk of visually induced motion sickness (VIMS). Previously, the 6-item short version of the Visually Induced Motion Sickness Susceptibility Questionnaire (VIMSSQ short form) has been validated for predicting individual variation in VIMS. The aim of the current study was to investigate how the susceptibility to VIMS is correlated with other relevant factors in the general population. METHODS: A total of 440 participants (201M, 239F), mean age 33.6 (SD 14.8) years, completed an anonymous online survey of various questionnaires including the VIMSSQ, Motion Sickness Susceptibility Questionnaire (MSSQ), Vertigo in City questionnaire (VIC), Migraine (scale), Social & Work Impact of Dizziness (SWID), Syncope (faintness), and Personality (‘Big Five’ TIPI). RESULTS: The VIMSSQ correlated positively with the MSSQ (r = .50), VIC (r = .45), Migraine (r = .44), SWID (r = .28), and Syncope (r = .15). The most efficient Multiple Linear Regression model for the VIMSSQ included the predictors MSSQ, Migraine, VIC, and Age and explained 40% of the variance. Factor analysis of strongest correlates with VIMSSQ revealed a single factor loading with VIMSSQ, MSSQ, VIC, Migraine, SWID, and Syncope, suggesting a common latent variable of sensitivity. CONCLUSIONS: The set of predictors for the VIMSSQ in the general population has similarity with those often observed in patients with vestibular disorders. Based on these correlational results, we suggest the existence of continuum of underlying risk factors for sensitivity, from healthy population to patients with extreme visual vertigo and perhaps Persistent Postural-Perceptual Dizziness

Assessment worlds colliding? Negotiating between discourses of assessment on an online open course

Using the badged open course, Taking your first steps into Higher Education, this case study examines how assessment on online open courses draws on concepts of assessment used within formal and informal learning. Our experience was that assessment used within open courses, such as massive open online courses, is primarily determined by the requirements of quality assurance processes to award a digital badge or statement of participation as well as what is technologically possible. However, this disregards much recent work in universities that use assessment in support of learning. We suggest that designers of online open courses should pay greater attention to the relationship of assessment and learning to improve participant course completion

The Visually Induced Motion Sickness Susceptibility Questionnaire (VIMSSQ): Estimating Individual Susceptibility to Motion Sickness-Like Symptoms When Using Visual Devices

Objective Two studies were conducted to develop and validate a questionnaire to estimate individual susceptibility to visually induced motion sickness (VIMS). Background VIMS is a common side-effect when watching dynamic visual content from various sources, such as virtual reality, movie theaters, or smartphones. A reliable questionnaire predicting individual susceptibility to VIMS is currently missing. The aim was to fill this gap by introducing the Visually Induced Motion Sickness Susceptibility Questionnaire (VIMSSQ). Methods A survey and an experimental study were conducted. Survey: The VIMSSQ investigated the frequency of nausea, headache, dizziness, fatigue, and eyestrain when using different visual devices. Data were collected from a survey of 322 participants for the VIMSSQ and other related phenomena such as migraine. Experimental study: 23 participants were exposed to a VIMS-inducing visual stimulus. Participants filled out the VIMSSQ together with other questionnaires and rated their level of VIMS using the Simulator Sickness Questionnaire (SSQ). Results Survey: The most prominent symptom when using visual devices was eyestrain, and females reported more VIMS than males. A one-factor solution with good scale reliability was found for the VIMSSQ. Experimental study: Regression analyses suggested that the VIMSSQ can be useful in predicting VIMS (R2 = .34) as measured by the SSQ, particularly when combined with questions pertaining to the tendency to avoid visual displays and experience syncope (R2 = .59). Conclusion We generated normative data for the VIMSSQ and demonstrated its validity. Application The VIMSSQ can become a valuable tool to estimate one’s susceptibility to VIMS based on self-reports

Sweet cherry:composition, postharvest preservation, processing and trends for its future use

Background Sweet cherries (Prunus avium L.) are a nutritious fruit which are rich in polyphenols and have high antioxidant potential. Most sweet cherries are consumed fresh and a small proportion of the total sweet cherries production is value added to make processed food products. Sweet cherries are highly perishable fruit with a short harvest season, therefore extensive preservation and processing methods have been developed for the extension of their shelf-life and distribution of their products. Scope and Approach In this review, the main physicochemical properties of sweet cherries, as well as bioactive components and their determination methods are described. The study emphasises the recent progress of postharvest technology, such as controlled/modified atmosphere storage, edible coatings, irradiation, and biological control agents, to maintain sweet cherries for the fresh market. Valorisations of second-grade sweet cherries, as well as trends for the diversification of cherry products for future studies are also discussed. Key Findings and Conclusions Sweet cherry fruit have a short harvest period and marketing window. The major loss in quality after harvest include moisture loss, softening, decay and stem browning. Without compromising their eating quality, the extension in fruit quality and shelf-life for sweet cherries is feasible by means of combination of good handling practice and applications of appropriate postharvest technology. With the drive of health-food sector, the potential of using second class cherries including cherry stems as a source of bioactive compound extraction is high, as cherry fruit is well-known for being rich in health-promoting components

Universality in escape from a modulated potential well

We show that the rate of activated escape $W$ from a periodically modulated potential displays scaling behavior versus modulation amplitude $A$. For adiabatic modulation of an optically trapped Brownian particle, measurements yield $\ln W\propto (A_{\rm c} - A)^{\mu}$ with $\mu = 1.5$. The theory gives $\mu=3/2$ in the adiabatic limit and predicts a crossover to $\mu=2$ scaling as $A$ approaches the bifurcation point where the metastable state disappears.Comment: 4 pages, 3 figure

Effect of biocomposite edible coatings based on pea starch and guar gum on nutritional quality of ‘Valencia’ orange during storage

Application of environmentally friendly components is an approach for substitution of synthetic substances in commercial waxes applied to citrus. In this study, the effect of biocomposite edible coatings based on pea starch and guar gum (PSGG) on total vitamin C, phenolic, flavonoid, anthocyanins, and carotenoid content, and antioxidant capacity of ‘Valencia’ orange stored at 5 °C and 20 °C for four weeks were evaluated. The fruits were coated by a single layer PSGG coating, blended composite PSGG coating containing shellac (Sh) and oleic acid as hydrophobic compounds (PSGG-Sh), and a layer-by-layer (LBL) coating (PSGG as an internal layer and Sh as an external layer). The results showed no significant differences in changes of bioactive compounds between coating treatments after first week storage at both temperatures. The PSGG coatings incorporated with hydrophobic compounds (PSGG-Sh) better preserved the nutritional value and the antioxidant potential of oranges during storage compared with other treatments. The single layer PSGG coating was almost similar to bilayer coating in preserving nutritional value of fruit during storage and less effective than the blended composite PSGG-Sh coating

Characterization of pea starch-guar gum biocomposite edible films enriched by natural antimicrobial agents for active food packaging

Antimicrobial activity of epigallocatechin-3-gallate (EGCG) and two native Australian plants blueberry ash (BBA) fruit and macadamia (MAC) skin extracts against nine pathogenic and spoilage bacteria and seven strains of fungi, using an agar well diffusion assay were investigated. The minimum inhibitory concentrations (MIC) of these compounds were calculated using 96-well microtiter plates method. Finally, active antimicrobial packaging films were prepared by incorporation of EGCG, BBA and MAC extracts at 1-, 2-, 3-, and 4-fold of their correspondence MIC values into edible films based on pea starch and guar gum (PSGG). The antimicrobial activity of films was investigated against target microorganisms by agar disc diffusion technique and quantified using the viable cell count assay. Among the test microorganisms, Salmonella typhimurium and Rhizopus sp. were the most resistance to active films. Films containing EGCG showed the highest activity against all test strains. As the concentration of compounds increased higher than 2 × MIC, the mechanical characteristics of the films were affected considerably. The results indicated that EGCG-PSGG, BBA-PSGG and MAC-PSGG films can be used as active food packaging systems for preserving food safety and prolonging the shelf-life of the packaged food