Benjamin-Ono Kadomtsev-Petviashvili’s models in interfacial electro-hydrodynamics

Three-dimensional nonlinear potential free surface flows in the presence of vertical electric fields are considered. Both the effects of gravity and surface tension are included in the dynamic boundary condition. An asymptotic analysis (based on the assumptions of small depth and small free surface displacements) is presented. It is shown that the problem can be modelled by a Benjamin-Ono Kadomtsev-Petviashvili equation. Furthermore a fifth order Benjamin-Ono Kadomtsev-Petviashvili equation is derived to describe the flows in the particular case of values of the Bond number close to 1/3

Associations between highly active antiretroviral therapy and the presence of HPV, premalignant and malignant cervical lesions in sub-Saharan Africa, a systematic review : current evidence and directions for future research

Objectives: In sub-Saharan Africa, substantial international funding along with evidence-based clinical practice have resulted in an unparalleled scale-up of access to antiretroviral treatment at a higher CD4 count. The role and timing of highly active antiretroviral therapy (HAART) in mediating cervical disease remains unclear. The aim of this article is to systematically review all evidence pertaining to Africa and identify research gaps regarding the epidemiological association between HAART use and the presence of premalignant/malignant cervical lesions. Method: Five databases were searched until January 2017 to retrieve relevant literature from sub-Saharan Africa. Publications were included if they addressed prevalence, incidence or clearance of human papillomavirus (HPV) infection in women undergoing HAART as well as cytological or histological neoplastic abnormalities. Results: 22 studies were included, of which seven were prospective studies. Women receiving HAART are less likely to develop squamous intraepithelial lesions (SILs). There is evidence that duration of HAART along with the CD4 count may reduce the prevalence of high-risk HPV (HR-HPV), suggesting that without HAART, severe immunosuppression increases the risk of becoming or remaining infected with HR-HPV. Furthermore, according to existent literature, the CD4 count, rather than HAART coverage or its duration, plays a central role in the prevalence of cervical intraepithelial neoplasia (CIN) 2 and CIN 3. Conclusion: Our findings suggest a positive impact of HAART duration, in conjunction and interaction with CD4 count, on reducing the prevalence of HR-HPV. The greatest treatment effect might be seen among women starting at the lowest CD4 count, which may have a more instrumental role in cervical oncogenesis than either HAART use or the treatment duration on the prevalence of CIN 2 and CIN 3. There is still insufficient evidence to show a clear association between HAART coverage and the incidence of invasive cervical cancer. Enhanced surveillance on the impact of HAART treatment is crucial

Hybrid free-surface flows in a two-dimensional channel

Hybrid free-surface flows past disturbances in a two-dimensional channel are identified and studied. The fluid is assumed to be inviscid and incompressible, and the flow to be steady and irrotational. The disturbances consist of a step in the bottom of the channel and a flat object lying on the free-surface (e.g., a sluice gate). A weakly nonlinear one-dimensional analysis is used to classify the possible types of solutions, and nonlinear solutions are obtained numerically by a boundary integral equation method.Benjamin James Binder and Jean-Marc Vanden-Broec

Spurious diffusion in particle simulations of the Kolmogorov flow

Particle simulations of the Kolmogorov flow are analyzed by the Landau-Lifshitz fluctuating hydrodynamics. It is shown that a spurious diffusion of the center of mass corrupts the statistical properties of the flow. The analytical expression for the corresponding diffusion coefficient is derived.Comment: 10 pages, no figure

Webuye health and demographic surveillance systems baseline survey of soil-transmitted helmints and intestinal protozoa among children up to five years

Background. The intestinal parasitic infections (IPIs) are globally endemic, and they constitute the greatest cause of illness and disease worldwide. Transmission of IPIs occurs as a result of inadequate sanitation, inaccessibility to potable water, and poor living conditions. Objectives. To determine a baseline prevalence of IPIs among children of five years and below at Webuye Health and Demographic Surveillance (HDSS) area in western Kenya. Methods. Cross-sectional survey was used to collect data. Direct saline and formal-ether-sedimentation techniques were used to process the specimens. Descriptive and inferential statistics such as Chi-square statistics were used to analyze the data. Results. A prevalence of 52.3% (417/797) was obtained with the male child slightly more infected than the female (53.5% versus 51%), but this was not significant (χ2=0.482, P>0.05). Giardia lamblia and Entamoeba histolytica were the most common pathogenic IPIs with a prevalence of 26.1% (208/797) and 11.2% (89/797), respectively. Soil-transmitted helminths (STHs) were less common with a prevalence of 4.8% (38/797), 3.8% (30/797), and 0.13% (1/797) for Ascaris lumbricoides, hookworms, and Trichuris trichiura, respectively. Conclusions. Giardia lamblia and E. histolytica were the most prevalent pathogenic intestinal protozoa, while STHs were less common. Community-based health promotion techniques are recommended for controlling these parasites

Mode 2 waves on the continental shelf : ephemeral components of the nonlinear internal wavefield

Author Posting. © American Geophysical Union, 2010. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 115 (2010): C07001, doi:10.1029/2009JC005605.Shoreward propagating, mode 2 nonlinear waves appear sporadically in mooring records obtained off the coast of New Jersey in the summer of 2006. Individual mode 2 packets were tracked between two moorings separated by 1 km; however, packets could not be tracked between moorings separated by greater distances from one another (∼10 km). The inability to track individual packets large distances through the mooring array combined with detailed observations from a ship suggest that these waves are short lived. The evolution of the ship-tracked wave group was recorded using acoustic backscatter, acoustic Doppler current profilers, and turbulence profiling. The leading mode 2 wave quickly changed form and developed a tail of short, small-amplitude mode 1 waves. The wavelength of the mode 1 oscillations agreed with that expected for a copropagating tail on the basis of linear theory. Turbulent dissipation in the mixed layer and radiation of the short mode 1 waves contributed to rapid energy loss in the leading mode 2 wave, consistent with the observed decay rate and short life span of only a few hours. The energy in the leading mode 2 wave was 10–100 times smaller than the energy of mode 1 nonlinear internal waves observed during the experiment; however, the magnitudes of wave-localized turbulent dissipation were similar.This work was funded by the Office of Naval Research

Orthogonality catastrophe in a one-dimensional system of correlated electrons

We present a detailed numerical study of the orthogonality catastrophe exponent for a one-dimensional lattice model of spinless fermions with nearest neighbor interaction using the density matrix remormalization group algorithm. Keeping up to 1200 states per block we achieve a very great accuracy for the overlap which is needed to extract the orthogonality exponent reliably. We discuss the behavior of the exponent for three different kinds of a localized impurity. For comparison we also discuss the non-interacting case. In the weak impurity limit our results for the overlap confirm scaling behavior expected from perturbation theory and renormalization group calculations. In particular we find that a weak backward scattering component of the orthogonality exponent scales to zero for attractive interaction. In the strong impurity limit and for repulsive interaction we demonstrate that the orthogonality exponent cannot be extracted from the overlap for systems with up to 100 sites, due to finite size effects. This is in contradiction to an earlier interpretation given by Qin et al. based on numerical data for much smaller system sizes. Neverthless we find indirect evidence that the backward scattering contribution to the exponent scales to 1/16 based on predictions of boundary conformal field theory.Comment: 16 pages, Latex, 8 eps figures, submitted to Phys. Rev.

Dynamical Systems approach to Saffman-Taylor fingering. A Dynamical Solvability Scenario

A dynamical systems approach to competition of Saffman-Taylor fingers in a channel is developed. This is based on the global study of the phase space structure of the low-dimensional ODE's defined by the classes of exact solutions of the problem without surface tension. Some simple examples are studied in detail, and general proofs concerning properties of fixed points and existence of finite-time singularities for broad classes of solutions are given. The existence of a continuum of multifinger fixed points and its dynamical implications are discussed. The main conclusion is that exact zero-surface tension solutions taken in a global sense as families of trajectories in phase space spanning a sufficiently large set of initial conditions, are unphysical because the multifinger fixed points are nonhyperbolic, and an unfolding of them does not exist within the same class of solutions. Hyperbolicity (saddle-point structure) of the multifinger fixed points is argued to be essential to the physically correct qualitative description of finger competition. The restoring of hyperbolicity by surface tension is discussed as the key point for a generic Dynamical Solvability Scenario which is proposed for a general context of interfacial pattern selection.Comment: 3 figures added, major rewriting of some sections, submitted to Phys. Rev.

Métodos y progreso de la conservación de los recursos genéticos de los olmos en Europa

The progress made in the conservation of European elm genetic resources since the 1st International Elm Conference is reviewed, and the complementarity of in situ and ex situ methods is discussed. The financial support of the European Union to RESGEN project CT96-78 has permitted to co-ordinate and rationalize the ex situ conservation of elms. The project, which involved 17 partner institutes in nine west European countries, aimed at a better evaluation, conservation and utilisation of the existing collections of native elm clones. Main achievements are: establishing a common database of about 2,000 clones; characterizing over 500 clones through RAPDs and chloroplast DNA PCR-RFLPs molecular markers; completing and rationalizing the existing collections; establishing a long-term core collection of 850 clones; cryo-preserving a subset of 444 clones; and identifying clones of interest for breeding and prudent use in the reconstruction of countryside hedges. The «Noble Hardwoods» network of the pan-European programme EUFORGEN groups members representative of 31 countries, and promotes the dynamic conservation of the genetic resources of several genera of broadleaf forest trees, including Ulmus spp. Strategies for the conservation of the adaptive potential of elm resources were defined and will be disseminated among foresters and conservationists through «Guidelines» leaflets. Some countries have already started implementing conservation measures for U. laevis, associating in situ preservation and the establishment of seed orchards. Others are undertaking inventories, or acquiring genetic knowledge on target populations.Se discute el progreso realizado en la conservación de los olmos europeos desde la primera conferencia Internacional del Olmo y los métodos complementarios de conservación in situ y ex situ. El apoyo financiero de la Unión Europea al proyecto RESGEN CT96-78 ha permitido coordinar y racionalizar la conservación ex situ de los olmos. El proyecto, en el cual están involucrados 17 instituciones participantes en nueve países de Europa Occidental, tiene por objetivo una mejor evaluación, conservación y utilización de las colecciones actualmente existentes de clones nativos de olmo. Los principales logros son: el establecimiento de una base de datos común de aproximadamente 2.000 clones; la caracterización de más de 500 clones usando RAPD y marcadores moleculares PCR-RFLP de ADN cloroplástico; la finalización y racionalización de las colecciones existentes; el establecimiento a largo plazo de una colección central con 850 clones; la criopreservación de un conjunto de 444 clones; y la identificación de clones de interés para la mejora y para su uso en la restauración de setos en campo. La red «Noble Hardwoods» del programa pan-europeo EUFORGEN agrupa a miembros representantes de 31 países, y promueve la conservación dinámica de los recursos genéticos de varios géneros de árboles planifolios, incluido Ulmus spp.. Las estrategias para la conservación del potencial adaptativo de los recursos de los olmos se definieron y se dieron a conocer entre forestales y conservacionistas a través de folletos guía. Algunos países han comenzado ya a implementar medidas de conservación para U. laevis mediante el uso de la preservación in situ y el establecimiento de huertos semilleros. Otros están elaborando inventarios, o adquiriendo información genética de poblaciones de interés