Relevant Distance Research Articles

Insights into the dynamics of planetary interiors obtained through the study of global distribution of volcanoes I: Empirical calibration on Earth

The distribution of volcanic features is ultimately controlled by processes taking place beneath the surface of a planet. For this reason, characterization of volcano distribution at a global scale can be used to obtain insights concerning dynamic aspects of planetary interiors. Until present, studies of this type have focused on volcanic features of a specific type, or have concentrated on relatively small regions. In this paper, (the first of a series of three papers) we describe the distribution of volcanic features observed over the entire surface of the Earth, combining an extensive database of submarine and subaerial volcanoes. The analysis is based on spatial density contours obtained with the Fisher kernel. Based on an empirical approach that makes no a priori assumptions concerning the number of modes that should characterize the density distribution of volcanism we identified the most significant modes. Using those modes as a base, the relevant distance for the formation of clusters of volcanoes is constrained to be on the order of 100 to 200km. In addition, it is noted that the most significant modes lead to the identification of clusters that outline the most important tectonic margins on Earth without the need of making any ad hoc assumptions. Consequently, we suggest that this method has the potential of yielding insights about the probable occurrence of tectonic features within other planets.

Computational analysis of benzofuran-2-carboxlic acids as potent Pim-1 kinase inhibitors

Context: The three Pim serine/threonine kinases (Pim-1, Pim-2, and Pim-3) belong to a small family of kinases that regulate numerous signaling pathways fundamental to the development of tumors. Pim kinases’ overexpression has been reported in numerous solid and hematological tumors and, in particular, prostate cancer (Pim-1).Objectives: This study investigated the binding modes of benzofuran-2-carboxlic acids against Pim-1 kinase, hence providing useful information for the active inhibition of it.Materials and methods: In present study, molecular docking approach via MOE-Dock program was applied to predict the binding interactions of some known Pim-1 kinase inhibitors. First validation of the docking protocol was carried out by calculating RMSD for the co-crystallized and docked ligands. Using the same protocol, all the compounds were docked into the active site of Pim-1 kinase.Results: All the compounds showed significant interactions and good correlation with the experimental data. The results illustrate that compounds with optimum basicity and relevant distance between the acidic and basic groups showed optimum interactions with the active site residues of Pim-1 kinase.Conclusion: We hope that this study will be helpful in designing new, structurally diverse and more potent compounds for the active treatment of prostate cancer and other related diseases caused by deregulation of Pim-1 kinase.

Median and mean of the supremum of [formula omitted] normalized random holomorphic fields

We prove that the expected value and median of the supremum of L2 normalized random holomorphic fields of degree n on m-dimensional Kähler manifolds are asymptotically of order mlogn. There is an exponential concentration of measure of the sup norm around this median value. Prior results only gave the upper bound. The estimates are based on the entropy methods of Dudley and Sudakov combined with a precise analysis of the relevant distance functions and covering numbers using off-diagonal asymptotics of Bergman–Szegö kernels. Recent work on the critical value distribution is also used.

The role of valvular endothelial cell paracrine signaling and matrix elasticity on valvular interstitial cell activation

The effects of valvular endothelial cell (VlvEC) paracrine signaling on VIC phenotype and nodule formation were tested using a co-culture platform with physiologically relevant matrix elasticities and diffusion distance. 100 μm thin poly(ethylene glycol) (PEG) hydrogels of 3–27 kPa Young's moduli were fabricated in transwell inserts. VICs were cultured on the gels, as VIC phenotype is known to change significantly within this range, while VlvECs lined the underside of the membrane. Co-culture with VlvECs significantly reduced VIC activation to the myofibroblast phenotype on all gels with the largest percent decrease on the 3 kPa gels (∼70%), while stiffer gels resulted in approximately 20–30% decrease. Additionally, VlvECs significantly reduced αSMA protein expression (∼2 fold lower) on both 3 and 27 kPa gels, as well as the number (∼2 fold lower) of nodules formed on the 27 kPa gels. Effects of VlvECs were prevented when nitric oxide (NO) release was inhibited with l-NAME, suggesting that VlvEC produced NO inhibits VIC activation. Withdrawal of l-NAME after 3, 5, and 7 days with restoration of VlvEC NO production for 2 additional days led to a partial reversal of VIC activation (∼25% decrease). A potential mechanism by which VlvEC produced NO reduced VIC activation was studied by inhibiting initial and mid-stage cGMP pathway molecules. Inhibition of soluble guanylyl cyclase (sGC) with ODQ or protein kinase G (PKG) with RBrcGMP or stimulation of Rho kinase (ROCK) with LPA, abolished VlvEC effects on VIC activation. This work contributes substantially to the understanding of the valve endothelium's role in preventing VIC functions associated with aortic valve stenosis initiation and progression.

Study of Chinese Enterprises’ Overseas M & A: Based on National and Corporate Cultural Distance

Chinese enterprises’ overseas M & A reached $43.4 billion in 2012, and the number was 26.3 times that of 2003. With Chinese enterprises’ increased overseas M & A cases, Chinese are facing the challenges from culture. This paper studies national cultural distance and enterprise culture distance, and measure relevant distance for 16 Chinese M & A cases.

Spectroscopy of the breaking bond: the diradical intermediate of the ring opening in oxazole

Bond breaking is a challenging problem in both experimental and theoretical chemistry, due to the transient nature and multi-configurational electronic structure of dissociating molecules. We use anion photodetachment to probe the diradical interactions in the ring-opening reaction of oxazole and obtain a self-consistent picture of the breaking bond. Starting from the closed-shell cyclic molecule, the reaction is launched on the anion potential, as an attached electron cleaves a carbon-oxygen bond. In the photodetachment, two neutral potential regions are sampled. One corresponds to a completely dissociated bond, while the other - to the bond fragments separated by approximately 3 Å. At this chemically relevant distance, signatures of lingering through-space interactions between the radical centers are observed.

Fuzzy Radial Basis Function Neural Networks with information granulation and its parallel genetic optimization

Fuzzy modeling of complex systems is a challenging task, which involves important problems of dimensionality reduction and calls for various ways of improving the accuracy of modeling. The IG-FRBFNN, a hybrid architecture of the IG-FIS (Fuzzy Inference System) and FRBFNN (Fuzzy Radial Basis Function Neural Networks), is proposed to address these problems. The paper is concerned with the analysis and design of IG-FRBFNNs and their optimization by means of the Hierarchical Fair Competition-based Parallel Genetic Algorithm (HFC-PGA). In the proposed network, the membership functions of the premise part of the fuzzy rules of the IG-based FRBFNN model directly rely on the computation of the relevant distance between data points and the use of four types of polynomials such as constant, linear, quadratic and modified quadratic are considered for the consequent part of fuzzy rules. Moreover, the weighted Least Square (WLS) learning is exploited to estimate the coefficients of the polynomial forming the conclusion part of the rules. Since the performance of the IG-RBFNN model is affected by some key design parameters, such as a specific subset of input variables, the fuzzification coefficient of the FCM, the number of rules, and the order of polynomial of the consequent part of fuzzy rules, it becomes beneficial to carry out both structural as well as parametric optimization of the network. In this study, the HFC-PGA is used as a comprehensive optimization vehicle. The performance of the proposed model is illustrated by means of several representative numerical examples.

Soliton driven relaxation dynamics and protein collapse in the villin headpiece

Protein collapse from a random chain to the native state involves a dynamical phase transition. During the process, new scales and collective variables become excited while old ones recede and fade away. The presence of different phases and many scales causes formidable computational bottle-necks in approaches that are based on full atomic scale scrutiny. Here we propose a way to describe the folding and unfolding processes effectively, using only the biologically relevant time and distance scales. We merge a coarse grained Landau theory that models the static collapsed protein in the low-temperature limit with a Glauber protocol that describes finite-temperature relaxation dynamics in a statistical system which is out of thermal equilibrium. As an example we inspect the collapse of a HP35 chicken villin headpiece subdomain, a paradigm specimen in protein folding studies. We simulate the folding and unfolding process by repeated heating and cooling cycles between a given low-temperature, i.e. bad solvent, environment where the protein is collapsed and various different high-temperature, i.e. good solvent, environments. We find that as long as the high temperature value stays below a value in the range that separates the random walk phase from the self-avoiding walk phase, we consistently recover the native state upon cooling. But, when heated to sufficiently high temperatures, the native state practically never recurs. Our result confirms Anfinsen’s thermodynamical hypothesis and estimates a temperature range for its validity, in the case of villin.

Influence of Crystal Packing on an Organometallic Ruthenium(IV) Complex Structure: The Right Distance for the Right Reason

The chemically relevant intramolecular bond distance between a η3-allylic system and the metal center in a ruthenium complex has been reinvestigated by state-of-the-art dispersion-corrected DFT calculations. Previous works revealed significant deviations between the experimental X-ray crystal structure and results of molecular DFT gas-phase calculations. It was stated that this complex represents a general failure of DFT for transition-metal complex geometries. Our work shows that periodic DFT-D3 calculations for the crystal excellently reproduce all experimental data. The previously found deviations are attributed to crystal packing, the counterions, and improperly accounted dispersion interactions in the theoretical treatment.

Reading angles in maps.

Preschool children can navigate by simple geometric maps of the environment, but the nature of the geometric relations they use in map reading remains unclear. Here, children were tested specifically on their sensitivity to angle. Forty-eight children (age 47:15-53:30 months) were presented with fragments of geometric maps, in which angle sections appeared without any relevant length or distance information. Children were able to read these map fragments and compare two-dimensional to three-dimensional angles. However, this ability appeared both variable and fragile among the youngest children of the sample. These findings suggest that 4-year-old children begin to form an abstract concept of angle that applies both to two-dimensional and three-dimensional displays and that serves to interpret novel spatial symbols.

Volcano clustering determination: Bivariate Gauss vs. Fisher kernels

Underlying many studies of volcano clustering is the implicit assumption that vent distribution can be studied by using kernels originally devised for distribution in plane surfaces. Nevertheless, an important change in topology in the volcanic context is related to the distortion that is introduced when attempting to represent features found on the surface of a sphere that are being projected into a plane. This work explores the extent to which different topologies of the kernel used to study the spatial distribution of vents can introduce significant changes in the obtained density functions. To this end, a planar (Gauss) and a spherical (Fisher) kernels are mutually compared. The role of the smoothing factor in these two kernels is also explored with some detail. The results indicate that the topology of the kernel is not extremely influential, and that either type of kernel can be used to characterize a plane or a spherical distribution with exactly the same detail (provided that a suitable smoothing factor is selected in each case). It is also shown that there is a limitation on the resolution of the Fisher kernel relative to the typical separation between data that can be accurately described, because data sets with separations lower than 500km are considered as a single cluster using this method. In contrast, the Gauss kernel can provide adequate resolutions for vent distributions at a wider range of separations. In addition, this study also shows that the numerical value of the smoothing factor (or bandwidth) of both the Gauss and Fisher kernels has no unique nor direct relationship with the relevant separation among data. In order to establish the relevant distance, it is necessary to take into consideration the value of the respective smoothing factor together with a level of statistical significance at which the contributions to the probability density function will be analyzed. Based on such reference level, it is possible to create a hierarchy of clustering degrees that allows us to obtain significant information in a geologic (and particularly volcanic) context. To illustrate this aspect of the kernel method, two examples using volcanic fields along the Peninsula of Baja California and the American continent are reported.

LA EVOLUCIÓN PROGRAMÁTICA DE LOS PARTIDOS CHILENOS 1970-2009: DE LA POLARIZACIÓN AL CONSENSO

Este trabajo estima la posicion de los candidatos en el eje izquierda-derecha para las seis elecciones presidenciales realizadas entre 1970 y 2009, usando para el efecto la metodologia del Comparative Manifesto Project (CMP). Esto con el objeto de testear distintas hipotesis producidas en la literatura sobre la evolucion ideologica de los partidos chilenos, y medir la distancia ideologica entre los distintos partidos y coaliciones. Los resultados confirman, en general, que hacia 1970 la distancia ideologica entre la izquierda y el centro, por un lado, y la derecha por el otro, era muy pronunciada. Asimismo, confirma que desde 1989 la distancia ideologica entre las coaliciones principales (la Concertacion y la Alianza) es comparativamente mas moderada, ademas de estable, aun cuando se observa un mayor acercamiento en la decada de 2000. Por su parte, la Izquierda Extraparlamentaria tiene hoy posiciones programaticas mas moderadas que las de Allende en 1970.

A real‐time in vivo dosimetric verification method for high‐dose rate intracavitary brachytherapy of nasopharyngeal carcinoma

A real-time in vivo dosimetric verification method using metal-oxide-semiconductor field effect transistor (MOSFET) dosimeters has been developed for patient dosimetry in high-dose rate (HDR) intracavitary brachytherapy of nasopharyngeal carcinoma (NPC). The necessary calibration and correction factors for MOSFET measurements in (192)Iridium source were determined in a water phantom. With the detector placed inside a custom-made nasopharyngeal applicator, the actual dose delivered to the tumor was measured in vivo and compared to the calculated values using a commercial brachytherapy planning system. Five MOSFETs were independently calibrated with the HDR source, yielding calibration factors of 0.48 ± 0.007 cGy∕mV. The maximum sensitivity variation was no more than 7% in the clinically relevant distance range of 1-5 cm from the source. A total of 70 in vivo measurements in 11 NPC patients demonstrated good agreement with the treatment planning. The mean differences between the planned and the actually delivered dose within a single treatment fraction were -0.1% ± 3.8% and -0.1% ± 3.7%, respectively, for right and left side assessments. The maximum dose deviation was less than 8.5%. In vivo measurement using the real-time MOSFET dosimetry system is possible to evaluate the actual dose to the tumor received by the patient during a treatment fraction and thus can offer another line of security to detect and prevent large errors.

Shielding Artificially Increases the Attenuation of Water: Study of CT Gradient Attenuation Induced by Shielding (CT GAINS)

Quantitatively analyze the computed tomography (CT) attenuation effects caused by bismuth shields, which are used to reduce superficial organ dose. The solid water uniformity section of the American College of Radiology CT phantom was scanned with a modified chest CT protocol. Scans were performed with a bismuth breast shield in multiple configurations, emphasizing three clinically relevant orientations. Attenuation effects were measured as changes in mean Hounsfield unit (HU) values of equal midsagittal regions of interest (ROI). Multiple statistical techniques were used in regression analysis. Bismuth shielding resulted in significant positive shifts of the expected Hounsfield unit values. The mean nonshielded CT attenuation was -0.16 ± 0.75 HU. Based on the clinically relevant ROI distance from the shield (~3-16 cm), the shielded values ranged from 43.8-4 HU, 45.8-10.1 HU, and 50.6-4.5 HU for shields 1, 2, and 3, respectively. All shield configurations displayed a statistically significant shift (P < .0001) at all distance ranges. The best fitting regression model was a quadratic function of distance versus logarithmic function of HU. A prediction table of the approximate shift in water HU values as a function of ROI distance from the shield was generated per shield type from their respective close-fitting regressions. The data support the claim that bismuth shields increase the attenuation of water, which can cause inaccurate characterization of simple fluid, giving the appearance of complex fluid or even solid density. However, there is potential for anticipation of the attenuation effects to validate continued use of these shields for dose reduction.

Learning from yesterday's mistakes to fix tomorrow's problems: When functional counterfactual thinking and psychological distance collide

AbstractFunctional counterfactual thinking involves a unique set of circumstances where one can both reflect on past events and imagine future possibilities. A key aspect of a counterfactual's functionality is that insight about past mistakes is converted into plans for future action, thereby improving self‐regulatory success. If counterfactual thinking is a self‐regulatory tool, then it should be similarly impacted by psychological mechanisms that influence peoples' ability to improve future outcomes. The current research tested one such mechanism, psychological distance. Using a sequential priming paradigm, Experiment 1 showed that functional counterfactual thinking is sensitive to changes in temporal distance. Negative events in the recent versus distant past facilitated relevant behavioral intention judgments. Additionally, functional counterfactual thinking was sensitive to changes in the relevant behavioral intention's temporal distance, such that counterfactual judgments facilitated behavioral intentions set to occur in the near but not distant future (Experiment 2). Together, this research creates new connections between functional counterfactual thinking and psychological distance. Copyright © 2012 John Wiley &amp; Sons, Ltd.

Adaptive generalized metrics, distance maps and nearest neighbor transforms on gray tone images

This paper aims to introduce and study two novel metrics on gray tone images. These metrics are based on the General Adaptive Neighborhood Image Processing (GANIP) framework that enables to represent an image by spatial neighborhoods, named General Adaptive Neighborhoods (GAN) that fit to their local context. These metrics are generalized in the sense that they do not satisfy all the axioms of a standard mathematical metric. This notion of adaptive generalized metrics leads to the definition of relevant GAN distance maps and GAN nearest neighbor transforms used for image segmentation.

Sorting by Transpositions Is Difficult

In comparative genomics, a transposition is an operation that exchanges two consecutive sequences of genes in a genome. The transposition distance between two genomes, that is, the minimum number of transpositions needed to transform a genome into another, is, according to numerous studies, a relevant evolutionary distance. The problem of computing this distance when genomes are represented by permutations is called the Sorting by Transpositions problem, and has been introduced by Bafna and Pevzner in [Proceedings of the Sixth Annual ACM-SIAM Symposium on Discrete Algorithms, 1995, pp. 614--623]. It has naturally been the focus of a number of studies (see, for instance, [G. Fertin, A. Labarre, I. Rusu, É. Tannier, and S. Vialette, Combinatorics of Genome Rearrangements, The MIT Press, Cambridge, MA, 2009]), but the computational complexity of this problem has remained undetermined for 15 years. In this paper, we answer this long-standing open question by proving that the Sorting by Transpositions problem is \sf NP-hard. As a corollary of our result, we also prove that the following problem, first described in [D. A. Christie, Genome Rearrangement Problems, Ph.D. thesis, University of Glasgow, Glasgow, Scotland, 1998], is \sf NP-hard: given a permutation $\pi$, is it possible to sort $\pi$ using exactly $d_b(\pi)/3$ transpositions, where $d_b(\pi)$ is the number of breakpoints of $\pi$?

A Relevant Distance Criterion for Interpolation of Head-Related Transfer Functions

In binaural synthesis, in order to realize more precise and accurate spatial sound, it would be desirable to measure a large number of the head-related transfer functions (HRTFs) in various directions. To reduce the size of the HRTFs, interpolation is often employed, where the HRTF for any direction can be obtained by a limited number of the representative HRTFs. In this paper, it is determined which distortion measure for interpolation of the HRTFs in the horizontal plane is most suitable for predicting audible differences in sound location. Four kinds of HRTF sets, measured using three human heads and one mannequin (KEMAR), were prepared for this study. Using various objective distortion criteria, the differences between interpolated and measured HRTFs were computed. These were then related to the results from the listening tests through receiver operator characteristic (ROC) curves. The results of the present study indicated that for the HRTF sets measured from three human heads, the best predictor of performance was obtained using the distortion measurement computed from the mel-cepstral coefficients, whereas the distortion measurement associated with interaural time delay predicted audible differences in sound location reasonably well for the KEMAR HRTF set. A feasibility test was conducted to verify the usefulness of the selected distortion measurement.

Sequential co-immobilization of thrombomodulin and endothelial protein C receptor on polyurethane: Activation of protein C

In an effort to control the surface-mediated activation of thrombin and clot formation, proteins and molecules which mimic the anticoagulant properties of the vascular endothelial lining were immobilized on material surfaces. When immobilized on biomaterial surfaces, thrombomodulin (TM), an endothelial glycoprotein that binds thrombin and activates protein C (PC), was shown to generate activated PC (APC) and delay clot formation. However, TM-mediated activation of PC on biomaterial surfaces was shown to be limited by the transport of PC to the surface, with maximum activation obtained at a surface density of ∼40 fmole TM cm −2. This work investigates surface immobilized with TM and endothelial protein C receptor (EPCR), a natural cofactor to TM which increases the rate of activation of PC on the native endothelium. A sequential and ordered immobilization of TM and EPCR on polyurethane at an enzymatically relevant distance (<10 nm) resulted in higher amounts of APC compared with surfaces with immobilized TM or with TM and EPCR immobilized randomly and at TM surface densities (1400 fmole cm −2) which were previously shown to be transport limited. Ordered TM and EPCR samples also showed increased time to clot formation in experiments with platelet-poor plasma, as measured by thromboelastography. Surfaces immobilized with TM and its natural cofactor EPCR at an enzymatically relevant distance are able to overcome transport limitations, increasing anticoagulant activation and time to clot formation.

Shock wave therapy for femoral head necrosis—Pressure measurements inside the femoral head

There is a persisting need for effective therapies of femoral head necrosis, a common bone disease. Promising clinical results have been stated for the treatment with extracorporeal shock waves (ESW). However, the effective remaining pressure in the target region inside the femoral head has never been determined. Aim of this study was to investigate whether ESW are able to propagate through bone without an excessive loss of pressure. The remaining ESW pressure generated by an electromagnetic device after passing a certain intraosseous distance within the femoral head was measured. Standardized holes were drilled in porcine femora and the absorption in relation to reference measurements in degassed water was determined. The results showed continuous attenuation of shock waves in bone. After a clinical relevant intraosseous distance of 10 mm an ESW pressure of ∼50% remained. In conclusion, ESW have the potential to reach necrotic regions with therapeutic pressure levels and to effectively treat femoral head necrosis.