Eikonal zeros in the momentum transfer space from proton-proton scattering: An empirical analysis

By means of improved empirical fits to the differential cross section data on $pp$ elastic scattering at $19.4 \le\sqrt{s}\le 62.5$ GeV and making use of a semi-analytical method, we determine the eikonal in the momentum transfer space (the inverse scattering problem). This method allows the propagation of the uncertainties from the fit parameters up to the extracted eikonal, providing statistical evidence that the imaginary part of the eikonal (real part of the opacity function) presents a zero (change of signal) in the momentum space, at $q^2 \approx 7 \pm 1$ GeV$^2$. We discuss the implication of this change of signal in the phenomenological context, showing that eikonal models with one zero provide good descriptions of the differential cross sections in the full momentum transfer range, but that is not the case for models without zero. Empirical connections between the extracted eikonal and results from a recent global analysis on the proton electric form factor are also discussed, in special the Wu-Yang conjecture. In addition, we present a critical review on the $pp$ differential cross section data presently available at high energies.Comment: Two references and some misprints corrected, 22 pages; final version to be published in Eur.Phys. J. C (2008

Total factor productividty growth in agriculture: the role of technological capital.

In this chapter we compute measures of total factor productivity (TFP) growth for developing countries and then contrast TFP growth with technological capital indexes. In developing these indexes, we incorporate schooling capital to yield two new indexes: Invention-Innovation Capital and Technology Mastery. We find that TFP performance is strongly related to technological capital and that technological capital is required for TFP and cost reduction growth. Investments in technological capital require long-term (20- to 40-year) investments, which are typically made by governments and aid agencies and are the only viable escape route from mass poverty

Improving adaptive bagging methods for evolving data streams

We propose two new improvements for bagging methods on evolving data streams. Recently, two new variants of Bagging were proposed: ADWIN Bagging and Adaptive-Size Hoeffding Tree (ASHT) Bagging. ASHT Bagging uses trees of different sizes, and ADWIN Bagging uses ADWIN as a change detector to decide when to discard underperforming ensemble members. We improve ADWIN Bagging using Hoeffding Adaptive Trees, trees that can adaptively learn from data streams that change over time. To speed up the time for adapting to change of Adaptive-Size Hoeffding Tree (ASHT) Bagging, we add an error change detector for each classifier. We test our improvements by performing an evaluation study on synthetic and real-world datasets comprising up to ten million examples

Creation of blenders in the conservative setting

In this work we prove that each C^r conservative diffeomorphism with a pair of hyperbolic periodic points of co-index one can be C^1-approximated by C^r conservative diffeomorphisms having a blender.Comment: 4 figures, 16 figure

On model-independent analyses of elastic hadron scattering

By means of an almost model-independent parametrization for the elastic hadron-hadron amplitude, as a function of the energy and the momentum transfer, we obtain good descriptions of the physical quantities that characterize elastic proton-proton and antiproton-proton scattering (total cross section, r parameter and differential cross section). The parametrization is inferred on empirical grounds and selected according to high energy theorems and limits from axiomatic quantum field theory. Based on the predictive character of the approach we present predictions for the above physical quantities at the Brookhaven RHIC, Fermilab Tevatron and CERN LHC energies.67567

Just preservation

We are failing to protect the biosphere. Novel views of conservation, preservation, and sustainability are surfacing in the wake of consensus about our failures to prevent extinction or slow climate change. We argue that the interests and well-being of non-humans, youth, and future generations of both human and non-human beings (futurity) have too long been ignored in consensus-based, anthropocentric conservation. Consensus-based stakeholder-driven processes disadvantage those absent or without a voice and allow current adult humans and narrow, exploitative interests to dominate decisions about the use of nature over its preservation for futurity of all life. We propose that authentically non-anthropocentric worldviews that incorporate multispecies justice are needed for a legitimate, deliberative, and truly democratic process of adjudication between competing interests in balancing the preservation and use of nature. Legitimate arenas for such adjudication would be courts that can defend intergenerational equity, which is envisioned by many nations\u27 constitutions, and can consider current and future generations of non-human life. We urge practitioners and scholars to disavow implicit anthropocentric value judgments in their work – or make these transparent and explicit – and embrace a more comprehensive worldview that grants future life on earth fair representation in humanity\u27s decisions and actions today

Notes on the feeding habits of Gaidropsarus guttatus (Collett, 1890) from Faial Island, Azores, NE Atlantic, PT

Copyright © 2014 Société Française d’Ichtyologie.Gaidropsarus guttatus est un prédateur nocturne des fonds rocheux des îles de Macaronésie. Il n’existe pas d’étude sur l’écologie alimentaire de cette espèce et cet article apporte les toutes premières informations, sur la base d’un échantillon de 82 individus capturés à l’île de Faial, aux Açores (Portugal). Les prélèvements ont été réalisés entre août 1997 et avril 1999 dans des mares intertidales et en zone subtidale jusqu’à une profondeur de 10 m. Sur les 82 spécimens collectés, 95% d’entre eux présentaient des aliments dans l’estomac, totalisant 303 proies de 11 taxons différents. Les proies les plus fréquentes étaient des décapodes (45%), notamment le crabe Pachygrapsus marmoratus (24%). Les poissons téléostéens représentaient 17% de toutes les proies identifiées. La présence significative de proies benthiques et d’algues dans les contenus stomacaux de G. guttatus suggèrent que cette espèce est un prédateur opportuniste qui utilise la succion pour capturer ses proies.ABSTRACT: Gaidropsarus guttatus is a nocturnal predator that dwells in rocky bottoms of Macaronesian coastal areas. There are no studies as yet on the feeding ecology of this species. This paper describes the feeding habits of this quite unknown species, based on a sample from Faial Island, Azores, Portugal. This sample is composed of 82 specimens collected between August 1997 and April 1999, both in intertidal pools and sub-tidal shallow waters (max. depth 10 m). 95% of sampled stomachs contained food items totaling 303 preys from 11 different taxa. Most important items were decapoda (45%), from which Pachygrapsus marmoratus (24%) showed to be clearly a dominant prey. Teleost fish represented 17% of all prey items. The significant presence of benthonic species and algae in their stomach contents do suggest that G. guttatus is an opportunistic suction feeder predator

A study on disability glare vision in young adult subjects

The full assessment of the visual system must include the evaluation of the optical quality of the eye and neural visual functions. The objective evaluation of the retinal image quality is often carried out by computing the point spread function (PSF) of the eye. The central part of the PSF is associated with optical aberrations and the peripheral areas with scattering contributions. In that sense, visual acuity and contrast sensitivity function tests can be considered the perceptual neural response to those contributions characterizing the eye’s PSF. However, in natural viewing conditions, visual acuity tests may provide good vision while contrast sensitivity tests can reveal visual impairment in glare vision conditions, such as exposure to bright light sources or night driving conditions. Here we present an optical instrument for the study of disability glare vision under extended Maxwellian illumination to assess the contrast sensitivity function under glare conditions. The limit of the Total Disability Glare threshold, tolerance, and glare adaptation will be investigated as a function of the angular size of the glare source (GA) and the contrast sensitivity function in young adult subjects