Accurate Picture (accurate + picture)

Distribution by Scientific Domains


Selected Abstracts


Standardising and mapping open-source information for crisis regions: the case of post-conflict Iraq

DISASTERS, Issue 3 2005
Sarah Mubareka
Abstract Painting an accurate picture of the situation on the ground in countries in crisis is vital for the efficiency of humanitarian aid and reconstruction agencies. This study describes a method for standardising and mapping the plethora of open-source information. The test site for the study is post-conflict Iraq. Important information on aid distribution, reconstruction and security in Iraq can be derived from the reports of humanitarian aid agencies and the media, before being formatted, inserted into a database and mapped. The product is a visual, cartographic structure of otherwise random information, showing which organisations are working in the country, which thematic and geographic areas are being prioritised in the field, and which areas most frequently experience security events. This type of mapping not only highlights the overall working environment within different parts of the country, but it may also serve as a decision-making tool for donors and humanitarian aid agencies planning to deploy personnel. [source]


Should biomass be considered more frequently as a currency in terrestrial arthropod community analyses?

JOURNAL OF APPLIED ECOLOGY, Issue 2 2007
MICHEL SAINT-GERMAIN
Summary 1Community structure involving large taxonomical groups is frequently used to assess changes in ecosystems along environmental gradients or in response to disturbance. For terrestrial arthropods, abundance is generally used as the response variable in community data analyses; biomass, however, is generally a better indicator of the functionality of a species within a community, as it is strongly correlated with metabolism. 2In this study, we considered whether biomass should be used more often in community analyses with terrestrial arthropod biodiversity data, particularly when asking questions involving strong functional components. We selected 10 previously published and five unpublished Coleoptera abundance data sets, and produced biomass species-by-sample matrices using body length to body mass conversion equations, and then compared the results obtained using commonly used ecological analyses. 3Correlations between species abundance and biomass varied from strong to poor, depending on the taxa considered and on the sampling method used. We show that abundance and biomass can produce different results in community data analysis and lead to alternative interpretations for data sets with poor abundance to biomass correlations. 4Synthesis and applications. When dealing with databases showing poor abundance to biomass relationships, the question of the relevance of using biomass instead of abundance emerges, and the choice of the response variable to be used in analyses should be considered carefully. At the very least, when studying terrestrial arthropod biodiversity, one should consider the use of biomass with simple conversion equations that do not require obtaining the mass of individual specimens. This approach may lead to different interpretations. For research questions in which trophic interactions may play an important role, biomass may provide a broader and more accurate picture of the processes driving changes in community structure. [source]


Logical Positivism, Analytic Method, and Criticisms of Ethnophilosophy

METAPHILOSOPHY, Issue 4 2004
Polycarp Ikuenobe
Abstract: I argue that the analytic method has been circularly used to analyze the concept of "philosophy," and that the result of this analysis has also been used to criticize African ethnophilosophy as nonphilosophical. I critically examine the criticism that ethnophilosophy implies cognitive relativism and the criticism that it implies authoritarianism. I defend ethnophilosophy against these criticisms, arguing that they are rooted in logical positivism, the view that philosophy essentially involves the use of the methods of science and logical analysis. I argue that such analysis and criticisms, given their pedigree, do not provide an adequate or accurate picture of the nature of philosophy. [source]


Refined structure of bovine carboxypeptidase A at 1.25,Å resolution

ACTA CRYSTALLOGRAPHICA SECTION D, Issue 2 2003
Alexandra Kilshtain-Vardi
The crystal structure of the bovine zinc metalloproteinase carboxypeptidase A (CPA) has been refined to 1.25,Å resolution based on room-temperature X-ray synchrotron data. The significantly improved structure of CPA at this resolution (anisotropic temperature factors, R factor = 10.4%, Rfree = 14.5%) allowed the modelling of conformational disorders of side chains, improved the description of the protein solvent network (375 water molecules) and provided a more accurate picture of the interactions between the active-site zinc and its ligands. The calculation of standard uncertainties in individual atom positions of the refined model of CPA allowed the deduction of the protonation state of some key residues in the active site and confirmed that Glu72 and Glu270 are negatively charged in the resting state of the enzyme at pH 7.5. These results were further validated by theoretical calculations that showed significant reduction of the pKa of these side chains relative to solution values. The distance between the zinc-bound solvent molecule and the metal ion is strongly suggestive of a neutral water molecule and not a hydroxide ion in the resting state of the enzyme. These findings could support both the general acid/general base mechanism, as well as the anhydride mechanism suggested for CPA. [source]


Protein folding simulations: From coarse-grained model to all-atom model

IUBMB LIFE, Issue 6 2009
Jian Zhang
Abstract Protein folding is an important and challenging problem in molecular biology. During the last two decades, molecular dynamics (MD) simulation has proved to be a paramount tool and was widely used to study protein structures, folding kinetics and thermodynamics, and structure,stability,function relationship. It was also used to help engineering and designing new proteins, and to answer even more general questions such as the minimal number of amino acid or the evolution principle of protein families. Nowadays, the MD simulation is still undergoing rapid developments. The first trend is to toward developing new coarse-grained models and studying larger and more complex molecular systems such as protein,protein complex and their assembling process, amyloid related aggregations, and structure and motion of chaperons, motors, channels and virus capsides; the second trend is toward building high resolution models and explore more detailed and accurate pictures of protein folding and the associated processes, such as the coordination bond or disulfide bond involved folding, the polarization, charge transfer and protonate/deprotonate process involved in metal coupled folding, and the ion permeation and its coupling with the kinetics of channels. On these new territories, MD simulations have given many promising results and will continue to offer exciting views. Here, we review several new subjects investigated by using MD simulations as well as the corresponding developments of appropriate protein models. These include but are not limited to the attempt to go beyond the topology based G,-like model and characterize the energetic factors in protein structures and dynamics, the study of the thermodynamics and kinetics of disulfide bond involved protein folding, the modeling of the interactions between chaperonin and the encapsulated protein and the protein folding under this circumstance, the effort to clarify the important yet still elusive folding mechanism of protein BBL, the development of discrete MD and its application in studying the ,,, conformational conversion and oligomer assembling process, and the modeling of metal ion involved protein folding. © 2009 IUBMB IUBMB Life, 61(6): 627,643, 2009 [source]


Micromotion and Stress Distribution of Immediate Loaded Implants: A Finite Element Analysis

CLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 4 2009
A. Fazel DDS
ABSTRACT Background: Primary stability and micromotion of the implant fixture is mostly influenced by its macrodesign. Purpose: To assess and compare the peri-implant stress distribution and micromotion of two types of immediate loading implants, immediate loaded screw (ILS) Nisastan and Xive (DENTSPLY/Friadent, Monnheim, Germany), and to determine the best macrodesign of these two implants by finite element analysis. Methods: In this experimental study, the accurate pictures of two fixtures (ILS: height = 13, diameter = 4 mm and Xive: height = 13, diameter = 3.8 mm) were taken by a new digital camera (Nikon Coolpix 5700 [Nikon, Japan], resolution = 5.24 megapixel, lens = 8× optical, 4× digital zoom). Following accurate measurements, the three-dimensional finite element computer model was simulated and inserted in simulated mandibular bone (D2) in SolidWorks 2003 (SolidWork Corp., MA, USA) and Ansys 7.1 (Ansys, Inc., Canonsburg, PA, USA). After loading (500 N, 75° above horizon), the displacement was displayed and von Mises stress was recorded. Results: It was found that the primary stability of ILS was greater (152 µm) than Xive (284 µm). ILS exhibited more favorable stress distribution. Maximum stress concentration found in periapical bone around Xive (,30 MPa) was lesser than Nisastan (,37 MPa). Conclusions: Macrodesign of ILS leads to better primary stability and stress distribution. Maximum stress around Xive was less. [source]