Geotraceability: an innovative concept to enhance conventional traceability in the agri-food chain

With the globalization of trade, people have become enlightened and demanding consumers as regards the origin of their food and the environment in which it is produced. The concept of geotraceability described in this article responds to that requirement by combining geographical information with conventional traceability data. The inclusion of geographical information relating to the environment of the production plots is based not only on exploiting some functionalities of spatial analysis tools that exist in geographical information systems (GIS) but also on developing specific tools such as a geoidentifier and geoindicators. This article also describes the characteristics and methods of implementing a geographical information management system linked with traceability information. Lastly, the potential for using geotraceability systems in supply chains is analyzed, in particular for consumer warnings in cases of food crisis and assistance for certification of differentiated quality agricultural products

Hormonal replacement therapy, prothrombotic mutations and the risk of venous thrombosis

Hormone replacement therapy (HRT) increases the risk of venous thrombosis. We investigated whether this risk is affected by carriership of hereditary prothrombotic abnormalities. Therefore, we determined the two most common prothrombotic mutations, factor V Leiden and prothrombin 20210A in women who participated in a case-control study on venous thrombosis. Relative risks were expressed as odds ratios (OR) with 95% confidence intervals (CI95). Among 7 7 women aged 45-64 years with a first venous thrombosis, 51% were receiving HRT at the time of thrombosis, compared with 24% of control women (OR = 3.3, CI95 1.8-5.8). Among the patients, 23% had a prothrombotic defect, versus 7% among the control women (OR = 3.8, CI95 1.7- 8.5). Women who had factor V Leiden and used HRT had a 15-fold increased risk (OR = 15.5, CI95 3.1-77), which exceeded the expected joint odds ratio of 6.1 (under an additive model). We conclude that the thrombotic risk of HRT may particularly affect women with prothrombotic mutations. Efforts to avoid HRT in women with increased risk of thrombosis are advisable

Velocity Correlations in Driven Two-Dimensional Granular Media

Simulations of volumetrically forced granular media in two dimensions produce s tates with nearly homogeneous density. In these states, long-range velocity correlations with a characteristic vortex structure develop; given sufficient time, the correlations fill the entire simulated area. These velocity correlations reduce the rate and violence of collisions, so that pressure is smaller for driven inelastic particles than for undriven elastic particles in the same thermodynamic state. As the simulation box size increases, the effects of veloc ity correlations on the pressure are enhanced rather than reduced.Comment: 12 pages, 6 figures, 21 reference

First 2-Hydroxy-3-Methylbut-3-Enyl Substituted Xanthones Isolated From Plants: Structure Elucidation, Synthesis and Antifungal Activity

Two new 2-hydroxy-3-methylbut-3-enyl substituted xanthones, ( - )-caledol 1 and ( - )-dicaledol 2 were isolated from a dichloromethane extract of the leaves of Calophyllum caledonicum (Clusiaceae). Compounds 1 and 2 are the first 2-hydroxy-3-methylbut-3-enyl substituted xanthones isolated from natural source. Their structures were elucidated by means of combined analytical methods including HRFABMS, 1D and 2D NMR spectroscopies and also confirmed by total synthesis using biomimetic ortho -prenylphenols photooxygenation ( 1 O 2 ) as a key step. The antifungal activity against Aspergillus fumigatus is reported

Quaterthiophenes with Terminal Indeno[1,2-b]thiophene Units as p-Type Organic Semiconductors

Quaterthiophenes 4T, Oct-4T, and Tol-4T based on a central 2,2′-bithiophene core α,ω-terminated with 4,4-unsubstituted and 4,4-disubstituted n-octyl or p-tolyl indeno[1,2-b]thiophene have been synthesized by Stille or Miyaura−Suzuki couplings. Compound 4T was also synthesized by an alternative route involving a soluble precursor bearing solubilizing trimethylsilyl groups which have been eliminated in the last step. The electronic properties of the compounds have been analyzed by cyclic voltammetry, UV−vis absorption and fluorescence emission spectroscopy. Thermal evaporation of 4T and Oct-4T leads to crystalline thin films and UV−vis absorption and X-ray diffraction data for these films suggest that the molecules adopt a quasi-vertical orientation onto the substrate. Strong π-π intermolecular interactions have been observed for 4T but not for molecules Oct-4T due to the presence of n-octyl chains. Sublimed thin films of Tol-4T show an amorphous character. The characterization of field-effect transistors fabricated from these three materials gave a hole-mobility of 2.2 × 10−2 cm2 V−1 s−1 with an on/off ratio of 2.2 × 104 for 4T while no field-effect was observed for Oct-4T and Tol-4T

Transport Coefficients for Granular Media from Molecular Dynamics Simulations

Under many conditions, macroscopic grains flow like a fluid; kinetic theory pred icts continuum equations of motion for this granular fluid. In order to test the theory, we perform event driven molecular simulations of a two-dimensional gas of inelastic hard disks, driven by contact with a heat bath. Even for strong dissipation, high densities, and small numbers of particles, we find that continuum theory describes the system well. With a bath that heats the gas homogeneously, strong velocity correlations produce a slightly smaller energy loss due to inelastic collisions than that predicted by kinetic theory. With an inhomogeneous heat bath, thermal or velocity gradients are induced. Determination of the resulting fluxes allows calculation of the thermal conductivity and shear viscosity, which are compared to the predictions of granular kinetic theory, and which can be used in continuum modeling of granular flows. The shear viscosity is close to the prediction of kinetic theory, while the thermal conductivity can be overestimated by a factor of 2; in each case, transport is lowered with increasing inelasticity.Comment: 14 pages, 17 figures, 39 references, submitted to PRE feb 199

MPGDs in Compton imaging with liquid-xenon

The interaction of radiation with liquid xenon, inducing both scintillation and ionization signals, is of particular interest for Compton-sequences reconstruction. We report on the development and recent results of a liquid-xenon time-projection chamber, dedicated to a novel nuclear imaging technique named "3 gamma imaging". In a first prototype, the scintillation is detected by a vacuum photomultiplier tube and the charges are collected with a MICROMEGAS structure; both are fully immersed in liquid xenon. In view of the final large-area detector, and with the aim of minimizing dead-zones, we are investigating a gaseous photomultiplier for recording the UV scintillation photons. The prototype concept is presented as well as preliminary results in liquid xenon. We also present soft x-rays test results of a gaseous photomultiplier prototype made of a double Thick Gaseous Electron Multiplier (THGEM) at normal temperature and pressure conditions.Comment: presented at MPGD09, CRETE, June 2009; to be published in JINST Proceedings, PDF, 10 pages, 11 figure

Geometric origin of mechanical properties of granular materials

Some remarkable generic properties, related to isostaticity and potential energy minimization, of equilibrium configurations of assemblies of rigid, frictionless grains are studied. Isostaticity -the uniqueness of the forces, once the list of contacts is known- is established in a quite general context, and the important distinction between isostatic problems under given external loads and isostatic (rigid) structures is presented. Complete rigidity is only guaranteed, on stability grounds, in the case of spherical cohesionless grains. Otherwise, the network of contacts might deform elastically in response to load increments, even though grains are rigid. This sets an uuper bound on the contact coordination number. The approximation of small displacements (ASD) allows to draw analogies with other model systems studied in statistical mechanics, such as minimum paths on a lattice. It also entails the uniqueness of the equilibrium state (the list of contacts itself is geometrically determined) for cohesionless grains, and thus the absence of plastic dissipation. Plasticity and hysteresis are due to the lack of such uniqueness and may stem, apart from intergranular friction, from small, but finite, rearrangements, in which the system jumps between two distinct potential energy minima, or from bounded tensile contact forces. The response to load increments is discussed. On the basis of past numerical studies, we argue that, if the ASD is valid, the macroscopic displacement field is the solution to an elliptic boundary value problem (akin to the Stokes problem).Comment: RevTex, 40 pages, 26 figures. Close to published paper. Misprints and minor errors correcte