Development of MY FRAM matrix to assess food safety risks in horticultural crops

A farm food safety risk assessment matrix (MY FRAM) was developed for horticultural farms. The tool enables farmers to carry out self risk assessments on the potential of food safety risks on the farm from site selection to post-harvest handling. MY FRAM was developed on Microsoft ASP. NET C# 4.5 with logical functions and utilised a semi-quantitative risk assessment approach (risk ranking of 1 – 9) for farmers. MY FRAM is an illustrative risk ranking tool to allow farmers to quickly identify potential food safety risks and risk summary and corrective actions are suggested to farms on how to reduce the risks. The tool can also be utilised as a training tool for farm workers to understand the importance of food safety at the farm level

Stochastic Calculus for a Time-changed Semimartingale and the Associated Stochastic Differential Equations

It is shown that under a certain condition on a semimartingale and a time-change, any stochastic integral driven by the time-changed semimartingale is a time-changed stochastic integral driven by the original semimartingale. As a direct consequence, a specialized form of the Ito formula is derived. When a standard Brownian motion is the original semimartingale, classical Ito stochastic differential equations driven by the Brownian motion with drift extend to a larger class of stochastic differential equations involving a time-change with continuous paths. A form of the general solution of linear equations in this new class is established, followed by consideration of some examples analogous to the classical equations. Through these examples, each coefficient of the stochastic differential equations in the new class is given meaning. The new feature is the coexistence of a usual drift term along with a term related to the time-change.Comment: 27 pages; typos correcte

On the origin of plankton patchiness

Plankton is the productive base of aquatic ecosystems and plays a major role in the global control of atmospheric carbon dioxide. Nevertheless, after intensive study, the factors that drive its spatial distribution are still far from being clear. The models proposed so far show very limited agreement with actual data as many of their results are not consistent with field observations. Here we show that fluctuations and turbulent diffusion in standard prey-predator models are able to accurately and consistently explain plankton field observations at mesoscales (1-100 km). This includes not only the spatial pattern but also its temporal evolution. We explicitly elucidate the interplay between physical and biological factors, suggesting that the form in which small scale biotic fluctuations are transferred to larger scales may constitute one of the key elements in determining the spatial distribution of plankton in the sea.Comment: 16 pages, 3 figure

Child Well-Being in Rich Countries: UNICEF’s Ranking Revisited, and New Symmetric Aggregating Operators Exemplified

In a report published in 2007 UNICEF measured six dimensions of child well-being for the majority of the economically advanced nations. No overall scores are given, but countries are listed in the order of their average rank on the dimensions, which are therefore implicitly assigned ‘equal importance’. In this study we take ‘equal importance’ to mean that the final aggregation is symmetrical in the scores and the ranks, i.e. permuting them leaves the aggregate unchanged. We rank the countries by aggregating the numerical information using a variety of techniques, geared to the measurement scales we distinguish (‘ordinal’, ‘interval’, ‘ratio’). The aggregators are symmetrical and mildly demanding, emphasizing good performance across the board. The rankings obtained deviate from the UNICEF ranking, but not over-dramatically. Our purpose is not only to study alternative approaches for the particular data at hand, but also to introduce and exemplify new and useful aggregation techniques: we propose ways to select weights for OWA-operators and weighted geometric means, and we suggest how to circumvent the choice of a power for the power means. In addition we extend the Borda method so that it values dominance as well

Boson gas in a periodic array of tubes

We report the thermodynamic properties of an ideal boson gas confined in an infinite periodic array of channels modeled by two, mutually perpendicular, Kronig-Penney delta-potentials. The particle's motion is hindered in the x-y directions, allowing tunneling of particles through the walls, while no confinement along the z direction is considered. It is shown that there exists a finite Bose- Einstein condensation (BEC) critical temperature Tc that decreases monotonically from the 3D ideal boson gas (IBG) value $T_{0}$ as the strength of confinement $P_{0}$ is increased while keeping the channel's cross section, $a_{x}a_{y}$ constant. In contrast, Tc is a non-monotonic function of the cross-section area for fixed $P_{0}$. In addition to the BEC cusp, the specific heat exhibits a set of maxima and minima. The minimum located at the highest temperature is a clear signal of the confinement effect which occurs when the boson wavelength is twice the cross-section side size. This confinement is amplified when the wall strength is increased until a dimensional crossover from 3D to 1D is produced. Some of these features in the specific heat obtained from this simple model can be related, qualitatively, to at least two different experimental situations: $^4$He adsorbed within the interstitial channels of a bundle of carbon nanotubes and superconductor-multistrand-wires Nb$_{3}$Sn.Comment: 9 pages, 10 figures, submitte

A renormalisation group approach to two-body scattering in the presence of long-range forces

We apply renormalisation-group methods to two-body scattering by a combination of known long-range and unknown short-range potentials. We impose a cut-off in the basis of distorted waves of the long-range potential and identify possible fixed points of the short-range potential as this cut-off is lowered to zero. The expansions around these fixed points define the power countings for the corresponding effective field theories. Expansions around nontrivial fixed points are shown to correspond to distorted-wave versions of the effective-range expansion. These methods are applied to scattering in the presence of Coulomb, Yukawa and repulsive inverse-square potentials.Comment: 22 pages (RevTeX), 4 figure

Aalenian to Cenomanian Radiolaria of the Bermeja Complex (Puerto Rico) and Pacific origin of radiolarites on the Caribbean Plate

The study of the radiolarian ribbon chert is a key in determining the origins of associated Mesozoic oceanic terranes and may help to achieve a general agreement regarding the basic principles on the evolution of the Caribbean Plate. The Bermeja Complex of Puerto Rico, which contains serpentinized peridotite, altered basalt, amphibolite, and chert (Mariquita Chert Formation), is one of these crucial oceanic terranes. The radiolarian biochronology presented in this work is mainly based by correlation on the biozonations of Baumgartner et al. (1995) and O'Dogherty (1994) and indicates an early Middle Jurassic to early Late Cretaceous (late Bajocian-early Callovian to late early Albian-early middle Cenomanian) age. The illustrated assemblages contain about 120 species, of which one is new (Pantanellium karinae), and belonging to about 50 genera. A review of the previous radiolarian published works on the Mariquita Chert Formation and the results of this study suggest that this formation ranges in age from Middle Jurassic to early Late Cretaceous (late Aalenian to early-middle Cenomanian) and also reveal a possible feature of the Bermeja Complex, which is the younging of radiolarian cherts from north to south, evoking a polarity of accretion. On the basis of a currently exhaustive inventory of the radiolarite facies s.s. on the Caribbean Plate, a re-examination of the regional distribution of Middle Jurassic sediments associated with oceanic crust, and a paleoceanographic argumentation on the water currents, we come to the conclusion that the radiolarite and associated Mesozoic oceanic terranes of the Caribbean Plate are of Pacific origin. Eventually, a discussion on the origin of the cherts of the Mariquita Formation illustrated by Middle Jurassic to middle Cretaceous geodynamic models of the Pacific and Caribbean realms bring up the possibility that the rocks of the Bermeja Complex are remnants of two different oceans

Deconstructing 1S0 nucleon-nucleon scattering

A distorted-wave method is used to analyse nucleon-nucleon scattering in the 1S0 channel. Effects of one-pion exchange are removed from the empirical phase shift to all orders by using a modified effective-range expansion. Two-pion exchange is then subtracted in the distorted-wave Born approximation, with matrix elements taken between scattering waves for the one-pion exchange potential. The residual short-range interaction shows a very rapid energy dependence for kinetic energies above about 100 MeV, suggesting that the breakdown scale of the corresponding effective theory is only 270MeV. This may signal the need to include the Delta resonance as an explicit degree of freedom in order to describe scattering at these energies. An alternative strategy of keeping the cutoff finite to reduce large, but finite, contributions from the long-range forces is also discussed.Comment: 10 pages, 2 figures (introduction revised, references added; version to appear in EPJA