SciCombinator

Discover the most talked about and latest scientific content & concepts.

Concept: Derivative

179

Politicians world-wide frequently promise a better life for their citizens. We find that the probability that a country will increase its per capita GDP (gdp) rank within a decade follows an exponential distribution with decay constant λ = 0.12. We use the Corruption Perceptions Index (CPI) and the Global Competitiveness Index (GCI) and find that the distribution of change in CPI (GCI) rank follows exponential functions with approximately the same exponent as λ, suggesting that the dynamics of gdp, CPI, and GCI may share the same origin. Using the GCI, we develop a new measure, which we call relative competitiveness, to evaluate an economy’s competitiveness relative to its gdp. For all European and EU countries during the 2008-2011 economic downturn we find that the drop in gdp in more competitve countries relative to gdp was substantially smaller than in relatively less competitive countries, which is valuable information for policymakers.

Concepts: European Union, Radioactive decay, Probability theory, Derivative, Exponential growth, Exponential function, Competitiveness, Global Competitiveness Report

169

SUMMARY: Pathview is a novel tool set for pathway based data integration and visualization. It maps and renders user data on relevant pathway graphs. Users only need to supply their data and specify the target pathway. Pathview automatically downloads the pathway graph data, parses the data file, maps and integrates user data onto the pathway, and renders pathway graphs with the mapped data. Although built as a stand-alone program, Pathview may seamlessly integrate with pathway and functional analysis tools for large-scale and fully automated analysis pipelines. AVAILABILITY: The package is freely available under the GPLv3 licence through Bioconductor and R-Forge. It is available at http://bioconductor.org/packages/release/bioc/html/pathview.html and at http://Pathview.r-forge.r-project.org/. CONTACT: luo_weijun@yahoo.com.

Concepts: Mathematics, Integral, Vector space, Derivative, Functional analysis

121

We have conducted a population-based study of pleural mesothelioma patients with occupational histories and measured asbestos lung burdens in occupationally exposed workers and in the general population. The relationship between lung burden and risk, particularly at environmental exposure levels, will enable future mesothelioma rates in people born after 1965 who never installed asbestos to be predicted from their asbestos lung burdens.

Concepts: Cancer, Metastasis, Lung cancer, Cancer staging, Pleural effusion, Derivative, Mesothelioma, Asbestos

33

In 2007, the province of British Columbia implemented incentive payments to primary care physicians for the provision of comprehensive, continuous, guideline-informed care for patients with 2 or more chronic conditions. We examined the impact of this program on primary care access and continuity, rates of hospital admission and costs.

Concepts: Medicine, Hospital, Physician, Calculus, Derivative, Provinces and territories of Canada, Canada, British Columbia

28

Current understanding of the term “concussion” is fraught with misconceptions regarding the extent and nature of brain injury. Despite increasing attention in popular media and within the context of sports, considerable gaps exist in our knowledge of the diagnosis, underlying brain pathology, recovery of function, and optimal interventions for concussion. In this special interest article, we discuss the definition and risk factors associated with concussion, summarize and highlight some of the most widely used assessment tools, and critique the evidence for current principles of concussion management. Our evaluation has identified opportunities for novel neuroimaging techniques to improve the understanding of the pathophysiology of concussion and to evaluate the changes in the recovering brain in response to rehabilitation. In summary, a clear definition of the underlying brain pathology, the potential long-term consequences, and the risk factors of injury and recovery will help guide future research aiming to minimize the impact of injury and develop innovative and successful therapeutic approaches aimed at ameliorating the functional impairments associated with concussion.Video Abstract available (see Video, Supplemental Digital Content 1, http://links.lww.com/JNPT/A51) for more insights from the authors.

Concepts: Traumatic brain injury, Neuroimaging, Derivative, Term, Concussion

28

Reoperation for failing stentless aortic valve replacement is a technically demanding procedure that has traditionally been tackled in one of two ways: either root replacement or the more conservative option of implanting a stented valve within the valve. We sought to determine the relative operative risks, follow-up status and medium to long-term survival of these two methods.

Concepts: Derivative, Left ventricle, Aortic valve, Valve, Valve Corporation, Aortic valve replacement, Aortic insufficiency

28

Localization microscopy relies on computationally efficient Gaussian approximations of the point spread function for the calculation of fluorophore positions. Theoretical predictions show that under specific experimental conditions, localization accuracy is significantly improved when the localization is performed using a more realistic model. Here, we show how this can be achieved by considering three-dimensional (3-D) point spread function models for the wide field microscope. We introduce a least-squares point spread function fitting framework that utilizes the Gibson and Lanni model and propose a computationally efficient way for evaluating its derivative functions. We demonstrate the usefulness of the proposed approach with algorithms for particle localization and defocus estimation, both implemented as plugins for ImageJ.

Concepts: Mathematics, Biology, Function, Microscope, Derivative, Microscopy, Continuous function, Point spread function

28

An approximate expression for Henry’s function, describing the electrophoretic mobility of a spherical colloidal particle in the limit of low surface potentials, is developed through a physical analogy to a colloidal particle with a linearly slipping surface (i.e. satisfies the Navier slip condition). The resulting expression reproduces Henry’s function with a relative error of no more than 0.1%. This approach is generalized for the electrophoretic mobility of a particle regardless of surface potential though necessary data for rigorous testing is lacking.

Concepts: Function, Colloid, Topology, Derivative, Numerical analysis, Potential, Colloidal chemistry, Zeta potential

28

With a view to development of novel sialidase inhibitors, mimetics of the natural inhibitor Neu5Ac2en have been prepared in which a phosphonate group replaces the sialic acid glycerol side chain. Different hex-4-en derivatives adopt half-chair conformations that place the glycosyl phosphonate in an equatorial position. For the α-L-threo-hex-4-en derivative this conformation is equivalent to that of Neu5Ac2en, and opposite to that seen for alkyl O-glycosides with the same overall stereochemistry.

Concepts: Tertiary structure, Stereochemistry, Calculus, Vector space, Derivative, Conformation, Conformational isomerism, Cyclohexane conformation

28

A series of ethylenediamine platinum(II) complexes connected through semi-rigid chains of 1,2-bis(4-pyridyl)ethane to DNA intercalating subunits (naphthalene, anthracene or phenazine) has been synthesized, and their interactions with calf thymus (CT) DNA have been evaluated by viscometric titrations and equilibrium dialysis experiments. The parent ligands that contain anthracene or phenazine chromophores showed a monointercalative mode of DNA interaction (especially the anthracene derivative), with apparent association constants in the order of 10(4)M(-1). The corresponding platinum(II) complexes bind CT DNA through bisintercalation, as established by the significant increase of DNA contour length inferred from viscosity measurements, and the association constants are in the order of 10(5)M(-1). The naphthalene derivatives, however, exhibit a mixed mode of interaction, which suggests a partial contribution of both intercalation and groove binding for the ligand, and monointercalation in the case of the platinum(II) complex. Competition dialysis experiments carried out on the intercalative compounds have revealed a moderate selectivity towards GC DNA sequences for the derivatives containing the anthracene chromophore.

Concepts: DNA, Benzene, Ligand, EDTA, Derivative, Ethidium bromide, Doxorubicin, Ethylenediamine