3,925 research outputs found
Harmonic numbers, Catalan's triangle and mesh patterns
The notion of a mesh pattern was introduced recently, but it has already
proved to be a useful tool for description purposes related to sets of
permutations. In this paper we study eight mesh patterns of small lengths. In
particular, we link avoidance of one of the patterns to the harmonic numbers,
while for three other patterns we show their distributions on 132-avoiding
permutations are given by the Catalan triangle. Also, we show that two specific
mesh patterns are Wilf-equivalent. As a byproduct of our studies, we define a
new set of sequences counted by the Catalan numbers and provide a relation on
the Catalan triangle that seems to be new
Quantitative prediction of multivalent ligand–receptor binding affinities for influenza, cholera, and anthrax inhibition
Multivalency achieves strong, yet reversible binding by the simultaneous formation of multiple weak bonds. It is a key interaction principle in biology and promising for the synthesis of high-affinity inhibitors of pathogens. We present a molecular model for the binding affinity of synthetic multivalent ligands onto multivalent receptors consisting of n receptor units arranged on a regular polygon. Ligands consist of a geometrically matching rigid polygonal core to which monovalent ligand units are attached via flexible linker polymers, closely mimicking existing experimental designs. The calculated binding affinities quantitatively agree with experimental studies for cholera toxin (n = 5) and anthrax receptor (n = 7) and allow to predict optimal core size and optimal linker length. Maximal binding affinity is achieved for a core that matches the receptor size and for linkers that have an equilibrium end-to-end distance that is slightly longer than the geometric separation between ligand core and receptor sites. Linkers that are longer than optimal are greatly preferable compared to shorter linkers. The angular steric restriction between ligand unit and linker polymer is shown to be a key parameter. We construct an enhancement diagram that quantifies the multivalent binding affinity compared to monovalent ligands. We conclude that multivalent ligands against influenza viral hemagglutinin (n = 3), cholera toxin (n = 5), and anthrax receptor (n = 7) can outperform monovalent ligands only for a monovalent ligand affinity that exceeds a core-size dependent threshold value. Thus, multivalent drug design needs to balance core size, linker length, as well as monovalent ligand unit affinity
The selection and use of pesticides in Bank financed public health projects
Vector, snail and rodent-borne diseases are responsible for a great deal of human morbidity and mortality in the tropical developing countries. Of the three methods for controlling tropical diseases, environmental, biological and chemical, pesticides are the best alternative. Whenever possible, however, these chemicals should be used in conjunction with environmental or biological methods and the appropriate drug or vaccine. Public health officials must be concerned that the compound chosen is safe for the user as well as inhabitants and domestic animals in the treated area. The method of control must also be appropriate for each targeted vector, because there are large biological differences among species. Some other considerations are that: (a) the chemical must be a narrow spectrum pesticide; (b) it should be effective in the proposed geographic area; (c) the target should be evaluated to check its resistance to a given chemical; and (d) the proposed pesticide must not pose a hazard to species that are not targeted.Earth Sciences&GIS,Health Monitoring&Evaluation,Pest Management,Montreal Protocol,Agricultural Knowledge&Information Systems
Generating functions for Wilf equivalence under generalized factor order
Kitaev, Liese, Remmel, and Sagan recently defined generalized factor order on
words comprised of letters from a partially ordered set by
setting if there is a subword of of the same length as
such that the -th character of is greater than or equal to the -th
character of for all . This subword is called an embedding of
into . For the case where is the positive integers with the usual
ordering, they defined the weight of a word to be
, and the corresponding weight
generating function . They then
defined two words and to be Wilf equivalent, denoted , if
and only if . They also defined the related generating
function where
is the set of all words such that the only embedding of
into is a suffix of , and showed that if and only if
. We continue this study by giving an explicit formula for
if factors into a weakly increasing word followed by a weakly
decreasing word. We use this formula as an aid to classify Wilf equivalence for
all words of length 3. We also show that coefficients of related generating
functions are well-known sequences in several special cases. Finally, we
discuss a conjecture that if then and must be
rearrangements, and the stronger conjecture that there also must be a
weight-preserving bijection such
that is a rearrangement of for all .Comment: 23 page
Hedonic Valuation of Sportfishing Harvest
A hedonic valuation strategy is introduced to estimate the marginal value of sportfishing harvest. The strategy uses market prices, thereby avoiding some of the measurement problems associated with the constructed or proxy prices used in common valuation methods. A charter fee hedonic equation is estimated using data from the market for offshore charter fishing in the Gulf of Mexico. The marginal value of sportfishing harvest is identified using spatial variation in harvest rates and fish sizes. A two-stage minimum distance estimator is used to address potential omitted variables and cluster-sampling issues. Our results demonstrate that valid estimates of the marginal value of sportfishing harvest can be derived directly using market prices. The estimated marginal value per fish is consistent with published estimates using alternative methods. Thus, the hedonic approach suggested in this article offers promise as an independent validation of the typical methods used to value sportfishing harvest.Sportfishing, charter boats, hedonic, revealed preference, valuation, Public Economics, Research Methods/ Statistical Methods, Q22, Q26, Q51,
Research communication for immediate impact: climate adaptation in Australia
Abstract
Research into climate change adaptation is challenged by funding organisations to demonstrate immediate research impact through near term reference in sector- specific communication and policy documents. Critically, research funded to inform decision makers and current policy about adapting to climate change must engage with end users and implement communication initiatives that lead to research adoption. Moreover, researchers need to better understand the components that contribute to effective engagement and communication to plan successful strategies to engage with the range of vulnerable sectors affected by climate change. Given the importance of research application, Primary Investigators for National Climate Change Adaptation Research Facility (NCCARF) funded projects had to consider end user engagement and communication. This paper identifies some common factors in three NCCARF cases which successfully demonstrated swift access to climate adaptation research in three sectors; human health, emergency management, and settlements and infrastructure. Early and ongoing engagement between researchers and the intended knowledge users shaped both the research focus and output formats. Stakeholders involved in coordinated and sustained communication programs disseminated and promoted the research through multiple channels. These agents of dissemination included; funders (NCCARF, universities and industry bodies); information users (government agencies and professional bodies), and both mass media and social media
ViBe (Virtual Berlin) - Immersive Interactive 3D Urban Data Visualization - Immersive interactive 3D urban data visualization
The project investigates the possibility of visualizing open source data in a 3D interactive virtual environment. We propose a new tool, 'ViBe'. We programmed 'ViBe' using Unity for its compatibility with HTC VIVE glasses for virtual reality (VR). ViBe offers an abstract visualization of open source data in a 3D interactive environment. The ViBe environment entails three main topics a) inhabitants, b) environmental factors, and c) land-use; acting as representatives of parameters for cities and urban design. Berlin serves as a case study. The data sets used are divided according to Berlin's twelve administrative districts. The user immerses into the virtual environment where they can choose, using the HTC Vive controllers, which district (or Berlin as a whole) they want information for and which topics they want to be visualized, and they can also teleport back and forth between the different districts. The goal of this project is to represent different urban parameters an abstract simulation where we correlate the corresponding data sets. By experiencing the city through visualized data, ViBe aims to provide the user with a clearer perspective onto the city and the relationship between its urban parameters. ViBe is designed for adults and kids, urban planners, politicians and real estate developers alike
The impact of Directive 2010/64/EU on the right to interpretation and translation in criminal proceedings
The paper gives an overview of the situation of legal interpreting and translation in EU member states, with particular reference to the findings of the CEPEJ study, and analyses crucial aspects related to the transposition of Directive 2010/64/EU
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