494 research outputs found
Tropicoporus drechsleri
Tropicoporus drechsleri is currently known from several sites in Argentina, in the Chaco and SelvaMisionera (Atlantic Forest), and one site in the western part of Santa Catarina State, Brazil, (also in the Atlantic Forest). It is a specific parasite of Cordia americana, and its distribution is expected to match that of its host, ranging between 20°-30° S latitude in South America, from the Atlantic Forest to the east up to the Andean mountains to the west, in the Chaco domain. It is also expected to be found in Bolivia, Paraguay and Uruguay. There are an estimated 400-500 sites throughout its host´s distribution, each potentially containing 10-20 mature individuals. Total population size is estimated at 5,000 to 10,000 mature individuals distributed in one subpopulation. A population size reduction of 10-20% in 70 years (three generations based on the phenology of the host tree) is suspected due to past and ongoing loss of suitable habitat in the Atlantic Forest and Chaco. Tropicoporus drechsleri is classified as Vulnerable.Fil: Drechsler Santos, Elisandro Ricardo. Universidade Federal de Santa Catarina; BrasilFil: Kossmann, T.. Universidade Federal de Santa Catarina; BrasilFil: Bittencourt, Felipe. Universidade Federal de Santa Catarina; BrasilFil: Salvador Montoya, Carlos Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; ArgentinaFil: da Cunha, K. M.. Universidade Federal de Santa Catarina; Brasi
Determining the impact regions of competing options in preference space
2017 ACM SIGMOD International Conference on Management of Data, SIGMOD 2017, Chicago, Illinois, USA, 14-19 May 2017In rank-aware processing, user preferences are typically represented by a numeric weight per data attribute, collectively forming a weight vector. The score of an option (data record) is defined as the weighted sum of its individual attributes. The highest-scoring options across a set of alternatives (dataset) are shortlisted for the user as the recommended ones. In that setting, the user input is a vector (equivalently, a point) in a d-dimensional preference space, where d is the number of data attributes. In this paper we study the problem of determining in which regions of the preference space the weight vector should lie so that a given option (focal record) is among the top-k score-wise. In effect, these regions capture all possible user profiles for which the focal record is highly preferable, and are therefore essential in market impact analysis, potential customer identification, profile-based marketing, targeted advertising, etc. We refer to our problem as k-Shortlist Preference Region identification (kSPR), and exploit its computational geometric nature to develop a framework for its efficient (and exact) processing. Using real and synthetic benchmarks, we show that our most optimized algorithm outperforms by three orders of magnitude a competitor we constructed from previous work on a different problem.Department of Computing2016-2017 > Academic research: refereed > Refereed conference paperbcw
Accurate ab initio spin densities
We present an approach for the calculation of spin density distributions for
molecules that require very large active spaces for a qualitatively correct
description of their electronic structure. Our approach is based on the
density-matrix renormalization group (DMRG) algorithm to calculate the spin
density matrix elements as basic quantity for the spatially resolved spin
density distribution. The spin density matrix elements are directly determined
from the second-quantized elementary operators optimized by the DMRG algorithm.
As an analytic convergence criterion for the spin density distribution, we
employ our recently developed sampling-reconstruction scheme [J. Chem. Phys.
2011, 134, 224101] to build an accurate complete-active-space
configuration-interaction (CASCI) wave function from the optimized matrix
product states. The spin density matrix elements can then also be determined as
an expectation value employing the reconstructed wave function expansion.
Furthermore, the explicit reconstruction of a CASCI-type wave function provides
insights into chemically interesting features of the molecule under study such
as the distribution of - and -electrons in terms of Slater
determinants, CI coefficients, and natural orbitals. The methodology is applied
to an iron nitrosyl complex which we have identified as a challenging system
for standard approaches [J. Chem. Theory Comput. 2011, 7, 2740].Comment: 37 pages, 13 figure
Threshold Laws for the Break-up of Atomic Particles into Several Charged Fragments
The processes with three or more charged particles in the final state exhibit
particular threshold behavior, as inferred by the famous Wannier law for (2e +
ion) system. We formulate a general solution which determines the threshold
behavior of the cross section for multiple fragmentation. Applications to
several systems of particular importance with three, four and five leptons
(electrons and positrons) in the field of charged core; and two pairs of
identical particles with opposite charges are presented. New threshold
exponents for these systems are predicted, while some previously suggested
threshold laws are revised.Comment: 40 pages, Revtex, scheduled for the July issue of Phys.Rev.A (1998
The Design of a Best Execution Market
The notion of best execution on securities markets is manifold. Best execution has different meanings to different market participants,
therefore, it is difficult to find a unique market structure that meets this requirements for all the participants.
Traditional market structures are either static or flexible, meaning that an individual market participant has no influence regarding the
concrete market structures characteristics, like e. g. the price discovery mechanism, trading frequency or the market transparency.
Traditional market structures are either static or flexible, meaning that an individual market participant has no influence regarding the
Focussing on customer orientation, we propose a new type of market structure: the dynamic market model, where participants individually
choose the characteristics of the market structure for each transaction they perform. Furthermore, this paper offers an approach to design
dynamic market models from scratch. We briefly sketch the necessary steps towards a dynamic market model.
Traditional market structures are either static or flexible, meaning that an individual market participant has no influence regarding the
Finally, we present AMTRAS; the prototype of an electronic trading system that was conceived and implemented following the
aforementioned approach. AMTRAS is an software-agent based bond trading system designed for the need of institutional investors. It
implements a dynamic market model, a sophisticated product- and partner matching scheme as well as an innovative price discovery
approach
Phallus glutinolens
Phallus glutinolens is a species endemic to Brazil, occurring in fragments of Atlantic Forest in southern and southeastern regions. Up to now, there are only a few records of the species from six different sites. The total population is estimated at around 4,800 mature individuals, in one subpopulation. Based on the habitat decline within the area, we suspect a population decline around 10% in the last three generations (20 years). Phallus glutinolens is, therefore, assessed as Vulnerable C2a(ii).Fil: Trierveiler Pereira, Larissa. Universidade de Sao Paulo; BrasilFil: Vieira de Miranda, M.. Universidade de Sao Paulo; BrasilFil: Hernández Caffot, María Luciana. Universidad Nacional de Jujuy. Instituto de Ecorregiones Andinas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Ecorregiones Andinas; ArgentinaFil: Baltazar, J. M.. Universidade Federal do São Carlos; BrasilFil: Martins da Cuña, K.. Universidade Federal do Rio Grande do Sul; BrasilFil: Alves Silva, G.. Universidade de Sao Paulo; BrasilFil: Kossmann, T.. Universidade Federal de Santa Catarina; BrasilFil: Palacio, M.. Universidade Federal do Rio Grande do Sul; BrasilFil: Drechsler Santos, E. R.. Universidade Federal de Santa Catarina; Brasi
A Comparative Study of Selected Physical and Biochemical Traits of Wild-Type and Transgenic Sorghum to Reveal Differences Relevant to Grain Quality
Transgenic sorghum featuring RNAi suppression of certain kafirins was developed recently, to address the problem of poor protein digestibility in the grain. However, it was not firmly established if other important quality parameters were adversely affected by this genetic intervention. In the present study several quality parameters were investigated by surveying several important physical and biochemical grain traits. Important differences in grain weight, density and endosperm texture were found that serve to differentiate the transgenic grains from their wild-type counterpart. In addition, ultrastructural analysis of the protein bodies revealed a changed morphology that is indicative of the effect of suppressed kafirins. Importantly, lysine was found to be significantly increased in one of the transgenic lines in comparison to wild-type; while no significant changes in anti-nutritional factors could be detected. The results have been insightful for demonstrating some of the corollary changes in transgenic sorghum grain, that emerge from imposed kafirin suppression
Intermanifold similarities in partial photoionization cross sections of helium
Using the eigenchannel R-matrix method we calculate partial photoionization
cross sections from the ground state of the helium atom for incident photon
energies up to the N=9 manifold. The wide energy range covered by our
calculations permits a thorough investigation of general patterns in the cross
sections which were first discussed by Menzel and co-workers [Phys. Rev. A {\bf
54}, 2080 (1996)]. The existence of these patterns can easily be understood in
terms of propensity rules for autoionization. As the photon energy is increased
the regular patterns are locally interrupted by perturber states until they
fade out indicating the progressive break-down of the propensity rules and the
underlying approximate quantum numbers. We demonstrate that the destructive
influence of isolated perturbers can be compensated with an energy-dependent
quantum defect.Comment: 10 pages, 10 figures, replacement with some typos correcte
Anti-Lysophosphatidic Acid Antibodies Improve Traumatic Brain Injury Outcomes
BACKGROUND: Lysophosphatidic acid (LPA) is a bioactive phospholipid with a potentially causative role in neurotrauma. Blocking LPA signaling with the LPA-directed monoclonal antibody B3/Lpathomab is neuroprotective in the mouse spinal cord following injury.
FINDINGS: Here we investigated the use of this agent in treatment of secondary brain damage consequent to traumatic brain injury (TBI). LPA was elevated in cerebrospinal fluid (CSF) of patients with TBI compared to controls. LPA levels were also elevated in a mouse controlled cortical impact (CCI) model of TBI and B3 significantly reduced lesion volume by both histological and MRI assessments. Diminished tissue damage coincided with lower brain IL-6 levels and improvement in functional outcomes.
CONCLUSIONS: This study presents a novel therapeutic approach for the treatment of TBI by blocking extracellular LPA signaling to minimize secondary brain damage and neurological dysfunction
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