Geometrical codification for clustering mixed categorical and numerical databases

This paper presents an alternative to cluster mixed databases. The main idea is to propose a general method to cluster mixed data sets, which is not very complex and still can reach similar levels of performance of some good algorithms. The proposed approach is based on codifying the categorical attributes and use a numerical clustering algorithm on the resulting database. The codification proposed is based on polar or spherical coordinates, it is easy to understand and to apply, the increment in the length of the input matrix is not excessively large, and the codification error can be determined for each case. The proposed codification combined with the well known k-means algorithm showed a very good performance in different benchmarks and has been compared with both, other codifications and other mixed clustering algorithms, showing a better or comparable performance in all cases.     

Determination of secondary structure of normal fibrin from human peripheral blood

The secondary structure of human fibrin from normal donors and from bovine and suilline plasma was studied by Fourier transform ir spectroscopy and a quantitative analysis of its secondary structure was suggested. For this purpose, a previously experimented spectrum deconvolution procedure based on the use of the Conjugate Gradient Minimisation Algorithm with the addition of suitable constraints was applied to the analysis of conformation-sensitive amide bands. This procedure was applied to amide I and III analysis of bovine and suilline fibrin, obtained industrially, and to amide III analysis of human fibrin clots. The analysis of both amide I and III in the first case was useful in order to test the reliability of the method. We found bovine, suilline, and human fibrin to contain about 30% alpha-helix (amide I and III components at 1653 cm-1, and 1312 and 1284 cm-1, respectively), 40% beta-sheets (amide I and III components at 1625 and 1231 cm-1, respectively) and 30% turns (amide I and III components at 1696, 1680, 1675 cm-1, and 1249 cm-1, respectively). The precision of the quantitative determination depends on the amount of these structures in the protein. Particularly, the coefficient of variation is < 10% for percentage values of amide I and III components > 15 and 5%, respectively. The good agreement of our quantitative data, obtained separately by amide I and amide III analysis, and consistent with a previous fibrinogen (from commercial sources) study that reports only information about fibrin beta-sheet content obtained by factor analysis, leads us to believe that the amounts of secondary structures found (alpha-helix, beta-sheets, and turns) are accurate.     

On the Use of AMl and PM3 Methods on Energetic Compounds

Stewart's new semi-empirical method MNDO-PM3 (PM3) is compared with the well known Dewar's AMl method in the study of nitrosubstituted compounds, and some energetic materials. PM3 method shows better performances than the AMl one. Adjacent lone pair/lone pair repulsion are better described at PM3 level and the known systematic correction of about −9 kcal/mol for each C-NO₂ group of the AMl method becomes +3.5 kcal/mol at PM3 level. PM3 results for N-NO₂ containing compounds are directly comparable with experimental gas phase data.     

Integrated Assessment of the European WFD Implementation in Extremely Overexploited Aquifers Through Participatory Modelling

Participatory methods provide an increasingly accepted path to integrated water assessment. This research describes an interdisciplinary exercise of scenario design and modelling, which provides a methodology to couple hard science numerical modelling approaches with the involvement of key water actors and socioeconomic issues. A decision support system based on probabilistic methods (Bayesian networks) is the tool chosen for dealing with the interdisciplinary issues involved in this aquifer. Given the long-standing conflicts in the area, modelling work largely focuses on carrying out an impact assessment produced by different scenarios established under the light of the mandatory objectives established by the European Union Water Framework Directive. This methodology is applied to a semi-arid aquifer located in SE Spain (Serral-Salinas) that represents an extreme case of intensive groundwater use. Irrigation has been a catalyst for welfare in the area for the past 40?years, despite the resulting large groundwater drawdown and continuous rise of groundwater pumping energy costs. Modelling results suggest that only a drastic change in the abstraction regime can produce a solution to long term sustainability of the aquifers. In addition, the impact assessment advises that such objectives are unlikely to be met due to the high economic costs of this action.     

Superconducting Sphere and Finite-Size Permanent Magnet: Force, Torque, and Alignment Effect Calculation

Using a local first-order interaction model, previously described, the force and torque between a superconducting sphere in the Meissner state and a finite-size permanent magnet are calculated. These findings are compared to results obtained by other models for the force based on the images method for a point magnetic dipole. It is demonstrated that the first-order calculation is a good approximation. Moreover, the torque between a superconducting sphere and a magnet in different positions and angular orientations is calculated for the first time. We describe the alignment effect that tends to align a magnet tangentially to the superconducting sphere surface. In addition, it is shown that the finiteness of the magnet reduces the magnitude of the repulsive force.     

Structure and Tautomerism of ANTA (aminonitrotriazole)

Energy and dipole moment calculations show 3-nitro-5- amino-1,2,4-triazole is the most stable tautomer of ANTA either in the gas phase and polar solvents, in agreement with X-ray findings. Our calculations predict that the 5-nitro-3-amino-1,2,4-triazole tautomer is more sensitive to shock or impact. Some discrepancies between semiempirical (AMI and PM3) calculations and ab initio (up to 6-31G*//6-31G) are studied.     

Germicidal UV Sensitivity of Bacteria in Aerosols and on Contaminated Surfaces

We compared the UV sensitivity of Bacillus atrophaeus (a surrogate for B. anthracis), Pantoea agglomerans (a bacterial simulant frequently used in biodefense studies), and Yersinia ruckeri (a surrogate for Yersinia pestis) either airborne or deposited on a semisolid (wet) agar surface. Bacterial vegetative cells were aerosolized into an exposure chamber and exposed for various lengths of time to an ultraviolet (UV) light source emitting at 254 nanometer (nm) (in the UVC region also known as UVGI). Aerosols were collected onto gelatin filters, which were dissolved, diluted, plated, and incubated to enumerate colony formation. In darkness (with the UV light switched off), it took between 170 and 330 s airborne (depending on the bacterial species) to decrease by 90% of the original load (i.e., by 1 Log₁₀) the number of viable organisms originally present. The fluence of UVC required to inactivate 90% (F_{–1 Log10}) of bacteria aerosolized into an atmosphere with 80–90% relative humidity corresponded to 70.3 J.m^?2, 73.3 J.m^?2 and 18.3 J.m^?2 for vegetative cells of B. atrophaeus, P. agglomerans, and Y. ruckeri cells, respectively. Additionally, the UV sensitivity of bacteria deposited directly on agar nutrient plates was determined after exposure to 254-nm UV with the F_–1Log10 for the same bacteria on surfaces corresponding to 128 J.m^?2, 28.1 J.m^?2, and 16.3 J.m^?2, respectively. These comparative results among different bacterial species, either airborne or on contaminated surfaces, should assist in predicting the survival of bacterial cells after transmission from infected patients or after an intentional release into the environment.     

Method to Determine the Number of Bacterial Spores Within Aerosol Particles

We describe methodology to reveal the number of microbial spores within aerosol particles. The procedure involves visualization under differential- interference-contrast microscopy enhanced by high-resolution photography and further analysis by computer-assisted imaging. The method was used to analyze spore of Bacillus globigii in aerosols generated by a small (pressured metered-dose inhaler type) generator. Particles consisting in 1 or 2 spores accounted for 85% of all generated particles. This percentage rose to 91% when the same aerosol was collected on an Andersen cascade impactor that collected particles larger than 0.65 μm and was even higher (96%) when particles larger than 3.3 μm were also eliminated. These results demonstrate that the imaging analysis of aerosol particles collected on glass slides is sensitive to even relatively small changes in aerosol particle composition. The accuracy of the enhanced microscopic method described herein (differences between visual and computer analysis were approximately 3% of the total particle counts) seems adequate to determine the spore composition of aerosols of interest in biodefense.     

Bioactive multilayer thin films of charged N,N-disubstituted hydrazine phosphorus dendrimers fabricated by layer-by-layer self-assembly

Charged N,N-disubstituted hydrazine phosphorus-containing dendrimers are deposited either as alternate all-dendrimers multilayers or alternating with linear polymers on 3-mercaptopropionic acid or 3-aminopropyldimethylethoxysilane coated surfaces via electrostatic layer-by-layer self-assembly. The behavior of the film formation is investigated by surface plasmon resonance spectroscopy and ellipsometry. Fetal cortical rat neurons were cultured on the dendrimer films in order to investigate the influence of the surface charge of the outermost layer on their adhesion and maturation. It was found that neurons attached preferentially and matured slightly faster on film surfaces terminated with positively charged dendrimers than on negatively charged surfaces.