ESTIMATING IMPLICIT MARGINAL PRICES OF QUALITY CHARACTERISTICS OF TOMATOES

A hedonic price function is developed for estimating the implicit prices for selected quality characteristics of fresh tomatoes at three points in the marketing season. The estimation of this function, proposed as a method of evaluating change in the post-harvest system, is accomplished using a flexible functional form. Those quality characteristics that most affect the price of tomatoes can help determine the economic feasibility of alternative handling techniques or new technologies.Demand and Price Analysis,

PRICING QUALITY ATTRIBUTES AT THE WHOLESALE LEVEL

Demand and Price Analysis,

Dvoretzky type theorems for multivariate polynomials and sections of convex bodies

In this paper we prove the Gromov--Milman conjecture (the Dvoretzky type theorem) for homogeneous polynomials on $\mathbb R^n$, and improve bounds on the number $n(d,k)$ in the analogous conjecture for odd degrees $d$ (this case is known as the Birch theorem) and complex polynomials. We also consider a stronger conjecture on the homogeneous polynomial fields in the canonical bundle over real and complex Grassmannians. This conjecture is much stronger and false in general, but it is proved in the cases of $d=2$ (for $k$'s of certain type), odd $d$, and the complex Grassmannian (for odd and even $d$ and any $k$). Corollaries for the John ellipsoid of projections or sections of a convex body are deduced from the case $d=2$ of the polynomial field conjecture

Projection Postulate and Atomic Quantum Zeno Effect

The projection postulate has been used to predict a slow-down of the time evolution of the state of a system under rapidly repeated measurements, and ultimately a freezing of the state. To test this so-called quantum Zeno effect an experiment was performed by Itano et al. (Phys. Rev. A 41, 2295 (1990)) in which an atomic-level measurement was realized by means of a short laser pulse. The relevance of the results has given rise to controversies in the literature. In particular the projection postulate and its applicability in this experiment have been cast into doubt. In this paper we show analytically that for a wide range of parameters such a short laser pulse acts as an effective level measurement to which the usual projection postulate applies with high accuracy. The corrections to the ideal reductions and their accumulation over n pulses are calculated. Our conclusion is that the projection postulate is an excellent pragmatic tool for a quick and simple understanding of the slow-down of time evolution in experiments of this type. However, corrections have to be included, and an actual freezing does not seem possible because of the finite duration of measurements.Comment: 25 pages, LaTeX, no figures; to appear in Phys. Rev.

Epizootic Landscapes: Sheep Scab and Regional Environment in England in 1279–1280

This essay looks at late-medieval rural landscapes of animal disease through the prism of sheep epizootics in England, caused by sheep scab, a highly acute and transmissive disease, whose first wave broke out in 1279–1280. The essay focuses on three regions in England: East Anglia, the Wiltshire-Hampshire Chalklands and Kent, each possessing distinct topographic and environmental features and exhibiting different rates of mortality. The study sets a theoretical model, based on the concept of ‘complexity theory’ and consisting of ten different principles, determining regional variances in dissemination of scab and in mortality patterns. A close analysis of the available statistical sources suggests that there was no ‘universal’ explanatory factor accounting for the correlation between regional geography and mortality rates, and that the situation varied not only from region to region, but from farm to farm, depending on a combination of several possible factors. It is only through a meticulous analysis of local, rather than regional, conditions that the complexity of the situation can begin to be appreciate

Alu insertion polymorphisms shared by Papio baboons and Theropithecus gelada reveal an intertwined common ancestry

© 2019 The Author(s). Background: Baboons (genus Papio) and geladas (Theropithecus gelada) are now generally recognized as close phylogenetic relatives, though morphologically quite distinct and generally classified in separate genera. Primate specific Alu retrotransposons are well-established genomic markers for the study of phylogenetic and population genetic relationships. We previously reported a computational reconstruction of Papio phylogeny using large-scale whole genome sequence (WGS) analysis of Alu insertion polymorphisms. Recently, high coverage WGS was generated for Theropithecus gelada. The objective of this study was to apply the high-Throughput poly-Detect method to computationally determine the number of Alu insertion polymorphisms shared by T. gelada and Papio, and vice versa, by each individual Papio species and T. gelada. Secondly, we performed locus-specific polymerase chain reaction (PCR) assays on a diverse DNA panel to complement the computational data. Results: We identified 27,700 Alu insertions from T. gelada WGS that were also present among six Papio species, with nearly half (12,956) remaining unfixed among 12 Papio individuals. Similarly, each of the six Papio species had species-indicative Alu insertions that were also present in T. gelada. In general, P. kindae shared more insertion polymorphisms with T. gelada than did any of the other five Papio species. PCR-based genotype data provided additional support for the computational findings. Conclusions: Our discovery that several thousand Alu insertion polymorphisms are shared by T. gelada and Papio baboons suggests a much more permeable reproductive barrier between the two genera then previously suspected. Their intertwined evolution likely involves a long history of admixture, gene flow and incomplete lineage sorting

Wnt signalling and cancer stem cells

[Abstract] Intracellular signalling mediated by secreted Wnt proteins is essential for the establishment of cell fates and proper tissue patterning during embryo development and for the regulation of tissue homeostasis and stem cell function in adult tissues. Aberrant activation of Wnt signalling pathways has been directly linked to the genesis of different tumours. Here, the components and molecular mechanisms implicated in the transduction of Wnt signal, along with important results supporting a central role for this signalling pathway in stem cell function regulation and carcinogenesis will be briefly reviewed.Ministerio de Ciencia e Innovación; SAF2008-0060