Effect of home-refrigerator storage temperature on tomato quality

Postharvest storage, handling and distribution of fruit at low temperatures is the most common and manageable approach to control ripening and subsequent deterioration and to maximize product shelf-life. However, tomatoes, as many other subtropical fruits, are susceptible to develop symptoms of chilling injury, a physiological disorder caused by the exposure to low temperature above the freezing point. Development of chilling injury depends on temperature, time, ripening stage and tomato type/cultivar. We studied the effect of home-refrigerator storage temperature on the quality of two types of tomato: cocktail tomato (cultivars ‘Amoroso’ and ‘Brioso’) and truss tomato (cultivars ‘Capricia’ and ‘Roterno’). Fully ripe tomatoes were stored for 10 days at two temperatures: 4°C as simulation of home-refrigerator storage and 15°C as an optimal storage temperature. We evaluated several quality parameters: weight loss, firmness, soluble solid content, titratable acidity, carbohydrates, titratable acidity and citrate content. Although we did not observe any apparent symptom of chilling injury, we found that 4°C temperature stimulates firmness decay in both cocktail tomato cultivars, increasing fruit susceptibility to mechanical injury. Moreover, already after 5 days of 4°C storage, tomatoes generally showed decreased sugar and increased acid content (especially in cocktail tomatoes) compared to 15°C stored fruit, indicating a loss of sensoric quality at 4°C

Inkjet printing of self-healing polymers for enhanced composite interlaminar properties

Inkjet printing has been used to introduce an organic system that demonstrates thermally activated self-healing in composites. The organic system is composed of monomers that, when polymerised, are capable of thermally activated self-healing through a reversible Diels–Alder mechanism. After being synthesised the monomers were formulated into inks and inkjet printed on to carbon fibre epoxy prepreg. The polymers were co-cured with the prepreg into composite laminates and the effect on the interlaminar properties of the resultant system was investigated. A single ply at the mid-plane of double cantilever beam specimens was shown to increase the initiation (by NL Point) of the interlaminar fracture toughness by 9%. The interlaminar fracture toughness with regards to crack propagation was shown to increase further by up to 27%. Increases in apparent interlaminar shear strength as measured by short beam shear of up to 11% were also observed compared to unprinted controls. After a thermal treatment the short beam shear specimens are retested and the printed specimens are shown to have significantly smaller decreases in properties compared to the control which is consistent with repair in the interlaminar region

b \to ss\bar{d}$ in a Vector Quark Model

The rare decay $b\to ss\bar{d}$ is studied in a vector quark model by adding the contributions from exotic vector-like quarks. We find that the contribution from box diagrams amounts to $10^{-9}$ in the branching ratio, while the $Z$-mediated tree level contribution is negligible.Comment: LaTeX, 9 pages with 1 figur

Exact solitary and periodic-wave solutions of the K(2,2) equation (defocusing branch)

An auxiliary elliptic equation method is presented for constructing exact solitary and periodic travelling-wave solutions of the K(2, 2) equation (defocusing branch). Some known results in the literature are recovered more efficiently, and some new exact travelling-wave solutions are obtained. Also, new stationary-wave solutions are obtained

Predictors of human-infective RNA virus discovery in the United States, China, and Africa, an ecological study

BACKGROUND: The variation in the pathogen type as well as the spatial heterogeneity of predictors make the generality of any associations with pathogen discovery debatable. Our previous work confirmed that the association of a group of predictors differed across different types of RNA viruses, yet there have been no previous comparisons of the specific predictors for RNA virus discovery in different regions. The aim of the current study was to close the gap by investigating whether predictors of discovery rates within three regions—the United States, China, and Africa—differ from one another and from those at the global level. METHODS: Based on a comprehensive list of human-infective RNA viruses, we collated published data on first discovery of each species in each region. We used a Poisson boosted regression tree (BRT) model to examine the relationship between virus discovery and 33 predictors representing climate, socio-economics, land use, and biodiversity across each region separately. The discovery probability in three regions in 2010–2019 was mapped using the fitted models and historical predictors. RESULTS: The numbers of human-infective virus species discovered in the United States, China, and Africa up to 2019 were 95, 80, and 107 respectively, with China lagging behind the other two regions. In each region, discoveries were clustered in hotspots. BRT modelling suggested that in all three regions RNA virus discovery was better predicted by land use and socio-economic variables than climatic variables and biodiversity, although the relative importance of these predictors varied by region. Map of virus discovery probability in 2010–2019 indicated several new hotspots outside historical high-risk areas. Most new virus species since 2010 in each region (6/6 in the United States, 19/19 in China, 12/19 in Africa) were discovered in high-risk areas as predicted by our model. CONCLUSIONS: The drivers of spatiotemporal variation in virus discovery rates vary in different regions of the world. Within regions virus discovery is driven mainly by land-use and socio-economic variables; climate and biodiversity variables are consistently less important predictors than at a global scale. Potential new discovery hotspots in 2010–2019 are identified. Results from the study could guide active surveillance for new human-infective viruses in local high-risk areas. FUNDING: FFZ is funded by the Darwin Trust of Edinburgh (https://darwintrust.bio.ed.ac.uk/). MEJW has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 874735 (VEO) (https://www.veo-europe.eu/)

The narrow X-ray tail and double H-alpha tails of ESO 137-002 in Abell 3627

We present the analysis of a deep Chandra observation of a ~2L_* late-type galaxy, ESO 137-002, in the closest rich cluster A3627. The Chandra data reveal a long (>40 kpc) and narrow tail with a nearly constant width (~3 kpc) to the southeast of the galaxy, and a leading edge ~1.5 kpc from the galaxy center on the upstream side of the tail. The tail is most likely caused by the nearly edge-on stripping of ESO 137-002's ISM by ram pressure, compared to the nearly face-on stripping of ESO 137-001 discussed in our previous work. Spectral analysis of individual regions along the tail shows that the gas throughout it has a rather constant temperature, ~1 keV, very close to the temperature of the tails of ESO 137-001, if the same atomic database is used. The derived gas abundance is low (~0.2 solar with the single-kT model), an indication of the multiphase nature of the gas in the tail. The mass of the X-ray tail is only a small fraction (<5%) of the initial ISM mass of the galaxy, suggesting that the stripping is most likely at an early stage. However, with any of the single-kT, double-kT and multi-kT models we tried, the tail is always "over-pressured" relative to the surrounding ICM, which could be due to the uncertainties in the abundance, thermal vs. non-thermal X-ray emission, or magnetic support in the ICM. The H-alpha data from SOAR show a ~21 kpc tail spatially coincident with the X-ray tail, as well as a secondary tail (~12 kpc long) to the east of the main tail diverging at an angle of ~23 degrees and starting at a distance of ~7.5 kpc from the nucleus. At the position of the secondary H-alpha tail, the X-ray emission is also enhanced at the ~2 sigma level. We compare the tails of ESO 137-001 and ESO 137-002, and also compare the tails to simulations. Both the similarities and differences of the tails pose challenges to the simulations. Several implications are briefly discussed.Comment: 15 pages, 6 figures, accepted for publication in Ap

Radiation from accelerated particles in relativistic jets with shocks, shear-flow, and reconnection

We have investigated particle acceleration and shock structure associated with an unmagnetized relativistic jet propagating into an unmagnetized plasma. Strong magnetic fields generated in the trailing jet shock lead to transverse deflection and acceleration of the electrons. We have self-consistently calculated the radiation from the electrons accelerated in the turbulent magnetic fields. We find that the synthetic spectra depend on the bulk Lorentz factor of the jet, the jet temperature, and the strength of the magnetic fields generated in the shock. We have also begun study of electron acceleration in the strong magnetic fields generated by kinetic shear (Kelvin-Helmholtz) instabilities. Our calculated spectra should lead to a better understanding of the complex time evolution and/or spectral structure from gamma-ray bursts, relativistic jets, and supernova remnants.Comment: 6 pages, 4 figures, 2012 Fermi Symposium proceedings - eConf C12102

Scarred Patterns in Surface Waves

Surface wave patterns are investigated experimentally in a system geometry that has become a paradigm of quantum chaos: the stadium billiard. Linear waves in bounded geometries for which classical ray trajectories are chaotic are known to give rise to scarred patterns. Here, we utilize parametrically forced surface waves (Faraday waves), which become progressively nonlinear beyond the wave instability threshold, to investigate the subtle interplay between boundaries and nonlinearity. Only a subset (three main types) of the computed linear modes of the stadium are observed in a systematic scan. These correspond to modes in which the wave amplitudes are strongly enhanced along paths corresponding to certain periodic ray orbits. Many other modes are found to be suppressed, in general agreement with a prediction by Agam and Altshuler based on boundary dissipation and the Lyapunov exponent of the associated orbit. Spatially asymmetric or disordered (but time-independent) patterns are also found even near onset. As the driving acceleration is increased, the time-independent scarred patterns persist, but in some cases transitions between modes are noted. The onset of spatiotemporal chaos at higher forcing amplitude often involves a nonperiodic oscillation between spatially ordered and disordered states. We characterize this phenomenon using the concept of pattern entropy. The rate of change of the patterns is found to be reduced as the state passes temporarily near the ordered configurations of lower entropy. We also report complex but highly symmetric (time-independent) patterns far above onset in the regime that is normally chaotic.Comment: 9 pages, 10 figures (low resolution gif files). Updated and added references and text. For high resolution images: http://physics.clarku.edu/~akudrolli/stadium.htm

A Quantum Hall Fluid of Vortices

In this note we demonstrate that vortices in a non-relativistic Chern-Simons theory form a quantum Hall fluid. We show that the vortex dynamics is controlled by the matrix mechanics previously proposed by Polychronakos as a description of the quantum Hall droplet. As the number of vortices becomes large, they fill the plane and a hydrodynamic treatment becomes possible, resulting in the non-commutative theory of Susskind. Key to the story is the recent D-brane realisation of vortices and their moduli spaces.Comment: 10 pages. v2(3): (More) References adde

Parameterization and Reconstruction of Quasi Static Universe

We study a possibility of the fate of universe, in which there is neither the rip singularity, which results in the disintegration of bound systems, nor the endless expansion, instead the universe will be quasi static. We discuss the parameterization of the corresponding evolution and the reconstruction of the scalar field model. We find, with the parameterization consistent with the current observation, that the current universe might arrive at a quasi static phase after less than 20Gyr.Comment: minor changes and Refs. added, publish in EPJ