Fractal properties of correlated invasion percolation patterns

We present results on Monte Carlo simulations for invasion percolation with trapping considering the presence of spatial size correlations, a problem which is relevant to multiphase flow in field scale of porous media. The correlations are generated through the dual site bond model, characterized by a spatial correlation length r0, which depends on the overlap between site and bond distributions. Our results indicate that in two-dimensional lattices the fractal dimension of the sample-spanning cluster, is non-universal and vary with the correlation. Comparison with other authors recent findings is presented.Fil: López, Raúl Horacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; ArgentinaFil: Vidales, Ana Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; ArgentinaFil: Zgrablich, G.. Universidad Autónoma Metropolitana; Méxic

An architectural framework for heterogeneous networking.

The growth over the last decade in the use of wireless networking devices has been explosive. Soon many devices will have multiple network interfaces, each with very different characteristics. We believe that a framework that encapsulates the key challenges of heterogeneous networking is required. Like a map clearly helps one to plan a journey, a framework is needed to help us move forward in this unexplored area. The approach taken here is similar to the OSImodel in which tightly defined layers are used to specify functionality, allowing a modular approach to the extension of systems and the interchange of their components, whilst providing a model that is more oriented to heterogeneity and mobility

Enraizamiento de internodios de Zea diploperennis Iltis, Doebley Guzman

Internodios de Zea diploperennis fueron inducidos a enraizar en posición horizontal o vertical en presencia de Ácido Indol Acético (AlA) en concentración de 5ppm. aplicado en pasta de lanolina en la región apical. La respuesta al enraizamiento fue observada en el lugar de aplicación en presencia o ausencia de AlA. cuando los internodios fueron colocados en posición horizontal. En internodios verticales el AlA inhibió la respuesta al enraizamiento

The shape of invasion perclation clusters in random and correlated media

The shape of two-dimensional invasion percolation clusters are studied numerically for both non-trapping (NTIP) and trapping (TIP) invasion percolation processes. Two different anisotropy quantifiers, the anisotropy parameter and the asphericity are used for probing the degree of anisotropy of clusters. We observe that in spite of the difference in scaling properties of NTIP and TIP, there is no difference in the values of anisotropy quantifiers of these processes. Furthermore, we find that in completely random media, the invasion percolation clusters are on average slightly less isotropic than standard percolation clusters. Introducing isotropic long-range correlations into the media reduces the isotropy of the invasion percolation clusters. The effect is more pronounced for the case of persisting long-range correlations. The implication of boundary conditions on the shape of clusters is another subject of interest. Compared to the case of free boundary conditions, IP clusters of conventional rectangular geometry turn out to be more isotropic. Moreover, we see that in conventional rectangular geometry the NTIP clusters are more isotropic than TIP clusters

Reduction of microorganisms in marinated poultry breast using oregano essential oil and power ultrasound

Marinated chicken meat is an ideal substrate for the growth of microorganisms. The aim of this study was to determine the effect of high-intensity ultrasound on the microbial flora of chicken meat marinated in oregano oil. Three concentrations of oregano oil (0%, 0.1%, and 0.3%) and two types of marination (traditional and highintensity ultrasound) were tested. Microorganisms were enumerated immediately after marination and on 7, 14, and 21 days of chilled storage. Marination in oregano oil resulted in significant differences (P<0.05) in the numbers of anaerobic, lactic acid bacteria, and mesophiles. Ultrasound with 0.1% OEO did not show any effect on the three types of bacteria. The treatment with 0.3% oregano oil and ultrasound had the greatest effect on controlling microbial growth. Therefore, a combination of ultrasound and oregano oil is the most appropriate option for reducing the growth of mesophilic, anaerobic, and lactic acid bacteria in vacuum-packed marinated chicken breasts during chilled storage

Effects of Scale-Free Disorder on the Anderson Metal-Insulator Transition

We investigate the three-dimensional Anderson model of localization via a modified transfer-matrix method in the presence of scale-free diagonal disorder characterized by a disorder correlation function $g(r)$ decaying asymptotically as $r^{-\alpha}$. We study the dependence of the localization-length exponent $\nu$ on the correlation-strength exponent $\alpha$. % For fixed disorder $W$, there is a critical $\alpha_{\rm c}$, such that for $\alpha < \alpha_{\rm c}$, $\nu=2/\alpha$ and for $\alpha > \alpha_{\rm c}$, $\nu$ remains that of the uncorrelated system in accordance with the extended Harris criterion. At the band center, $\nu$ is independent of $\alpha$ but equal to that of the uncorrelated system. The physical mechanisms leading to this different behavior are discussed.Comment: submitted to Phys. Rev. Let

Uptake of gases in bundles of carbon nanotubes

Model calculations are presented which predict whether or not an arbitrary gas experiences significant absorption within carbon nanotubes and/or bundles of nanotubes. The potentials used in these calculations assume a conventional form, based on a sum of two-body interactions with individual carbon atoms; the latter employ energy and distance parameters which are derived from empirical combining rules. The results confirm intuitive expectation that small atoms and molecules are absorbed within both the interstitial channels and the tubes, while large atoms and molecules are absorbed almost exclusively within the tubes.Comment: 9 pages, 12 figures, submitted to PRB Newer version (8MAR2K). There was an error in the old one (23JAN2K). Please download thi

Detection and dynamics of circulating tumor cells in patients with high-risk prostate cancer treated with radiotherapy and hormones: a prospective phase II study

BACKGROUND: Circulating tumor cells (CTCs) are an established prognostic marker in castration-resistant prostate cancer but have received little attention in localized high-risk disease. We studied the detection rate of CTCs in patients with high-risk prostate cancer before and after androgen deprivation therapy and radiotherapy to assess its value as a prognostic and monitoring marker. PATIENTS AND METHODS: We performed a prospective analysis of CTCs in the peripheral blood of 65 treatment-naive patients with high-risk prostate cancer. EpCAM-positive CTCs were enumerated using the CELLSEARCH system at 4 timepoints. A cut off of 0 vs >/= 1 CTC/7.5 ml blood was defined as a threshold for negative versus positive CTCs status. RESULTS: CTCs were detected in 5/65 patients (7.5%) at diagnosis, 8/62 (12.9%) following neoadjuvant androgen deprivation and 11/59 (18.6%) at the end of radiotherapy, with a median CTC count/7.5 ml of 1 (range, 1-136). Only 1 patient presented a positive CTC result 9 months after radiotherapy. Positive CTC status (at any timepoint) was not significantly associated with any clinical or pathologic factors. However, when we analyzed variations in CTC patterns following treatment, we observed a significant association between conversion of CTCs and stages T3 (P = 0.044) and N1 (P = 0.002). Detection of CTCs was not significantly associated with overall survival (P > 0.40). CONCLUSIONS: Our study showed a low detection rate for CTCs in patients with locally advanced high-risk prostate cancer. The finding of a de novo positive CTC count after androgen deprivation therapy is probably due to a passive mechanism associated with the destruction of the tumor. Further studies with larger samples and based on more accurate detection of CTCs are needed to determine the potential prognostic and therapeutic value of this approach in non-metastatic prostate cancer. TRIAL REGISTRATION: ClinicalTrials.gov ID: NCT01800058