Effects of package and storage conditions on the keeping quality of Perlette grapes

Einfluß der Verpackungs- und Lagerungsbedingungen auf die Haltbarkeit von Perlette-TraubenUm die Verluste zwischen Ernte und Verkauf von Perlette-Trauben zu verringern, wurde jeweils 1/4 eines SO2-Spenders („Dual Release" SO2 generator) in die 2 kg Trauben fassenden Polyäthylenbeutel gelegt; die Verpackungsbeutel waren mit Perforationen versehen, die 0,56; 0,84; 1,12; 1,40 und 1,68 % der Folienfläche ausmachten. Die gefüllten Beutel wurden bei 5, 15, 25, 30 und 35 °C (Freilandtemperatur) in belüftete 2-kg-Kartons aus Wellpappe verpackt und 60 d lang kühl gelagert (0-3 °C). Bei der Verkostung wurden die Trauben mit einer Verpackungstemperatur von 35 °C und 1,12%iger Perforation der Verpackungsqeutel am besten beurteilt. Die niedrigste Verpackungstemperatur (5 °C) und der niedrigste Perforationsgrad (0,56 %) verringerten beide den physiologischen Gewichtsverlust (PLW) und das Abfallen der Beeren am stärksten. PLW nahm mit der Dauer der Lagerung zu. Bis zu einer Lagerungsdauer von 40 d in zu 0,56 %, 0,85 % und 1,12 % perforierten Beuteln trat keine Beerenfäulnis auf; diese war jedoch auch bei erhöhter Perforation noch zu vernachlässigen. Die höchsten Mostgewichte wurden bei Verpakkungstemperaturen von 30 oder 35 °C nach 40tägiger Lagerung festgestellt; danach nahm das Mostgewicht ab. Die höchsten Säurewerte wurden bei Verpackungstemperaturen von 25 und 35 °C nach einer Lagerungsdauer von 40 d, bei 15 und 30 °C nach 60 d ermittelt. Demzufolge können PerletteTrauben durch beigepackte SO2-Spender in Folienbeuteln, die zu 1,12 % perforiert sind und Verpacken bei 35 °C bis zu 40 d erfolgreich gelagert werden

Social status modulates prosocial behavior and egalitarianism in preschool children and adults

Humans are a cooperative species, capable of altruism and the creation of shared norms that ensure fairness in society. However, individuals with different educational, cultural, economic, or ethnic backgrounds differ in their levels of social investment and endorsement of egalitarian values. We present four experiments showing that subtle cues to social status (i.e., prestige and reputation in the eyes of others) modulate prosocial orientation. The experiments found that individuals who experienced low status showed more communal and prosocial behavior, and endorsed more egalitarian life goals and values compared with those who experienced high status. Behavioral differences across high- and low-status positions appeared early in human ontogeny (4-5 y of age)

Metal nanoplasmas as bright sources of hard x-ray pulses

We report significant enhancements in light coupling to intense-laser-created solid plasmas via surface plasmon and "lightning rod" effects. We demonstrate this in metal nanoparticle-coated solid targets irradiated with 100 fs, 806 nm laser pulses, focused to intensities ~1014-1015Wcm-2. Our experiments show a 13-fold enhancement in hard x-ray yield (10-200 keV) emitted by copper nanoparticle plasmas formed at the focal volume. A simple model explains the observed enhancement quantitatively and provides pointers to the design of structured surfaces for maximizing such emissions

Short laser pulse induced generation of hot electrons and their anomalous stopping in overdense plasmas

In the fast ignition (FI) scheme of inertial confinement fusion, the igniter pulse falls on a precompressed overdense target and hence is unable to penetrate it. Thus, for the task of hot spot generation one has to rely on energetic electrons which are produced by the laser pulse at the critical surface. These electrons subsequently move towards the target core and deposit their energy in a sufficiently localized region. It is thus clear that the production of hot electrons by the incident sub-picosecond laser pulse at the critical surface and their subsequent transport in the overdense plasma region are the two main physics issues which are of relevance to the FI scheme. An experimental study and theoretical analysis which may be of relevance to these two issues are presented here. The study shows that the production of energetic electrons occurs through the wave breaking of plasma waves excited at the critical surface by the incident laser beam. Further, the propagation of hot electrons through the overdense region is influenced by electrostatically induced and/or by turbulence induced anomalous resistivity

Laser-pulse-induced second-harmonic and hard x-ray emission: role of plasma-wave breaking

We report time resolved measurements of second-harmonic and hard x rays emitted during the interaction of an intense laser pulse (1016 W cm-2, 100 fs) with a preplasma generated on a solid target. We observe that for a particular length scale the second harmonic goes through a minimum, while hard x-ray emission on the contrary maximizes. Theoretical or numerical modeling of this anticorrelation in terms of wave breaking of strongly driven electron plasma waves clearly brings out hitherto unexplored links between the physical mechanisms of second-harmonic generation and hard x-ray emission

Characterizing Distances of Networks on the Tensor Manifold

At the core of understanding dynamical systems is the ability to maintain and control the systems behavior that includes notions of robustness, heterogeneity, or regime-shift detection. Recently, to explore such functional properties, a convenient representation has been to model such dynamical systems as a weighted graph consisting of a finite, but very large number of interacting agents. This said, there exists very limited relevant statistical theory that is able cope with real-life data, i.e., how does perform analysis and/or statistics over a family of networks as opposed to a specific network or network-to-network variation. Here, we are interested in the analysis of network families whereby each network represents a point on an underlying statistical manifold. To do so, we explore the Riemannian structure of the tensor manifold developed by Pennec previously applied to Diffusion Tensor Imaging (DTI) towards the problem of network analysis. In particular, while this note focuses on Pennec definition of geodesics amongst a family of networks, we show how it lays the foundation for future work for developing measures of network robustness for regime-shift detection. We conclude with experiments highlighting the proposed distance on synthetic networks and an application towards biological (stem-cell) systems.Comment: This paper is accepted at 8th International Conference on Complex Networks 201

Enhanced hard x-ray emission from microdroplet preplasma

We perform a comparative study of hard x-ray emission from femtosecond laser plasmas in 15 mu m methanol microdroplets and Perspex target. The hard x-ray yield from droplet plasmas is similar or equal to 68 times more than that obtained from solid plasmas at 2x10(15) W cm(-2). A 10 ns prepulse at about 5% of the main pulse appears to be essential for hard x-ray generation from droplets. Hot electron temperature of 36 keV is measured from the droplets at 8x10(14) W cm(-2), whereas a three times higher intensity is needed to obtain similar hot electron temperatures from Perspex plasmas. Particle-in-cell simulations with very long scale-length density profiles support experimental observations. (c) 2006 American Institute of Physics