Void Scaling and Void Profiles in CDM Models

An analysis of voids using cosmological N-body simulations of cold dark matter models is presented. It employs a robust statistics of voids, that was recently applied to discriminate between data from the Las Campanas Redshift Survey and different cosmological models. Here we extend the analysis to 3D and show that typical void sizes D in the simulated galaxy samples obey a linear scaling relation with the mean galaxy separation lambda: D=D_0+nu*lambda. It has the same slope nu as in 2D, but with lower absolute void sizes. The scaling relation is able to discriminate between different cosmologies. For the best standard LCDM model, the slope of the scaling relation for voids in the dark matter halos is too steep as compared to the LCRS, with too small void sizes for well sampled data sets. The scaling relation of voids for dark matter halos with increasing mass thresholds is even steeper than that for samples of galaxy-mass halos where we sparse sample the data. This shows the stronger clustering of more massive halos. Further, we find a correlation of the void size to its central and environmental average density. While there is little sign of an evolution in samples of small DM halos with v_{circ} ~ 90 km/s, voids in halos with circular velocity over 200 km/s are larger at redshift z = 3 due to the smaller halo number density. The flow of dark matter from the underdense to overdense regions in an early established network of large scale structure is also imprinted in the evolution of the density profiles with a relative density decrease in void centers by 0.18 per redshift unit between z=3 and z=0.Comment: 12 pages, 9 eps figures, submitted to MNRA

Voids in the LCRS versus CDM Models

We have analyzed the distribution of void sizes in the two-dimensional slices of the Las Campanas Redshift Survey (LCRS). Fourteen volume-limited subsamples were extracted from the six slices to cover a large part of the survey and to test the robustness of the results against cosmic variance. Thirteen samples were randomly culled to produce homogeneously selected samples. We then studied the relationship between the cumulative area covered by voids and the void size as a property of the void hierarchy. We find that the distribution of void sizes scales with the mean galaxy separation, $\lambda$. In particular, we find that the size of voids covering half of the area is given by D_{med} \approx \lambda + (12\pm3) \h^{-2}Mpc. Next, by employing an environmental density threshold criterion to identify mock galaxies, we were able to extend this analysis to mock samples from dynamical $n$-body simulations of Cold Dark Matter (CDM) models. To reproduce the observed void statistics, overdensity thresholds of $\delta_{th} \approx 0 ... 1$ are necessary. We have compared standard (SCDM), open (OCDM), vacuum energy dominated ($\Lambda$CDM), and broken scale invariant CDM models (BCDM): we find that both the void coverage distribution and the two-point correlation function provide important and complementary information on the large-scale matter distribution. The dependence of the void statistics on the threshold criterion for the mock galaxy indentification shows that the galaxy biasing is more crucial for the void size distribution than are differences between the cosmological models.Comment: 10 pages, 8 eps figures, submitted to MNRA

Genetic variation of Giardia lamblia isolates from food-handlers in Kashan, Central Iran

<p><strong><em>Background:</em></strong> Based on genotyping study of human isolates of <em>Giardia lamblia</em>; humans are mainly infected by two assemblages A and B. The present study was carried out to determine the sub-assemblages of <em>G. lamblia</em> isolated from food handlers referred to Kashan health centers, central Iran, 2015.</p><p><strong><em>Methods:</em></strong> In this cross-sectional<strong> </strong>study,<strong> </strong>3653 stool samples collected from food-handlers that annually refer to health center for getting a health certification and examined microscopically for <em>G. lamblia</em> cyst. Totally, 44 isolates were selected from 47 <em>Giardia</em> positive samples. Cysts were partially purified by the sucrose density gradient method. After freeze-thaw cycles, genomic DNA was extracted using QIAamp Stool Mini kit. A single step PCR-RFLP method was used to amplify a 458bp fragment at the glutamate dehydrogenase <em>(gdh</em>) locus, restriction enzymes <em>BspLI </em>and <em>RsaI</em> were used for distinguish between genotypes A and B and their subgroups.</p><p><strong><em>Results:</em></strong> Of 44 isolates, 24(54.5%) were sub-assemblage AII, 9(20.5%) group B including 7(15.9%) BIII and 2(4.6%) BIV sub-assemblage and 11(25%) isolates showed a mixed pattern of AII and B. Sub-assemblage AI was not detected in this study.</p><strong><em>Conclusion:</em></strong> The higher rate of sub-assemblage AII demonstrated an anthroponotic origin of the infection so infected food-handlers could directly transmit this protozoan to consumers via contaminated food and water. For finding of pattern of transmission and distribution of <em>Giardia</em> assemblages and sub-assemblage, more studies in human and animal population in different regions are necessary

Copper adsorption from aqueous solution by activated carbon of wax beans waste activated by magnetite nanoparticles

Copper, a heavy metal, causes environmental pollution through a variety of industrial processes in many countries. Adsorption is known as an effective and efficient way of removing heavy metals. The present study was conducted mainly to magnetize the carbon in wax bean waste with magnetite nanoparticles and use it as adsorbent to remove copper from aqueous solution. Carbon was obtained from wax beans waste and activated with magnetite nanoparticles. The characteristics of obtaining adsorbent were studied and analyzed by FE-SEM, BET, and FT-IR. In this study, the effect of pH, adsorbent dose, contact time and copper concentration on the efficiency of copper removal was investigated per full factorial design by the Design Expert Software. The concentration of copper was measured by atomic absorption spectrophotometer (Varian AA240). For statistical analysis of the experiment’s data, ANOVA and P-value were used. Copper initial concentration 100 mg/L, adsorbent dose 1 g/L, pH 7 and contact time 40 min were obtained as optimal conditions for copper removal. Investigation of the isotherms indicated that the experimental data of the process were correlated with Langmuir Model. The maximum capacity of copper adsorption of Langmuir Model was 49.75 mg/g. Findings indicated that at optimal conditions, the amount of copper adsorbed from synthetic wastewater and real wastewater was 99.73% and 63%, respectively. Therefore, this method is capable of removing copper effectively and could be used to remove this metal from industrial wastewaters. © 2018 Desalination Publications. All rights reserved

Mean Subtraction and Mode Selection in Dynamic Mode Decomposition

Koopman mode analysis has provided a framework for analysis of nonlinear phenomena across a plethora of fields. Its numerical implementation via Dynamic Mode Decomposition (DMD) has been extensively deployed and improved upon over the last decade. We address the problems of mean subtraction and DMD mode selection in the context of finite dimensional Koopman invariant subspaces. Preprocessing of data by subtraction of the temporal mean of a time series has been a point of contention in companion matrix-based DMD. This stems from the potential of said preprocessing to render DMD equivalent to temporal DFT. We prove that this equivalence is impossible when the order of the DMD-based representation of the dynamics exceeds the dimension of the system. Moreover, this parity of DMD and DFT is mostly indicative of an inadequacy of data, in the sense that the number of snapshots taken is not enough to represent the true dynamics of the system. We then vindicate the practice of pruning DMD eigenvalues based on the norm of the respective modes. Once a minimum number of time delays has been taken, DMD eigenvalues corresponding to DMD modes with low norm are shown to be spurious, and hence must be discarded. When dealing with mean-subtracted data, the above criterion for detecting synthetic eigenvalues can be applied after additional pre-processing. This takes the form of an eigenvalue constraint on Companion DMD, or yet another time delay.Comment: 43 pages, 7 figure

Survey of hydatid cyst surgeries in hospitals affiliated to Ahvaz Jundishapur University of Medical Sciences during 2004 to 2014

Background: Hydatidosis is one of the most important zoonotic diseases with global distribution. Due to the prevalence of the disease in country, the study aimed to determine the clinical and laboratory findings in patients with hydatidosis admitted to surgical departments of educational hospitals, Imam Khomeini and Golestan, in Ahvaz city during 2004-2014. Materials and Methods: Data of the patients including demographic characteristics, and clinical and laboratory findings were recorded in a prepared form and analyzed using descriptive statistics and Chi-square tests by the SPSS software. Results: From a total of all patients, 49 (55.7) and 39 patients (44.3) were females and males respectively; 25 patients were resident in rural areas and 62 in urban areas. The mean age of the patients was 30.6&plusmn;2 years. Also, the maximum and minimum percentages of the disease were observed in the age group 20-29 and 80-89, respectively. Recurrence was observed in 9 patients. The highest prevalence of the hydatid cyst was in the right lobe of the liver (26.1). Among the methods of imaging, sonography and MRI had the highest and lowest use in the diagnosis of the disease, respectively. Conclusion: Findings of this study show that the most common organs affected are the liver and the younger age group and suburbs are more prone to hydatidosis. Due to the chronicity of the disease and the late diagnosis during the visit, screening for endemic areas and high-risk persons is recommended

Non-universality of elastic exponents in random bond-bending networks

We numerically investigate the rigidity percolation transition in two-dimensional flexible, random rod networks with freely rotating cross-links. Near the transition, networks are dominated by bending modes and the elastic modulii vanish with an exponent f=3.0\pm0.2, in contrast with central force percolation which shares the same geometric exponents. This indicates that universality for geometric quantities does not imply universality for elastic ones. The implications of this result for actin-fiber networks is discussed.Comment: 4 pages, 3 figures, minor clarifications and amendments. To appear in PRE Rap. Com

Chitosan-titanium dioxide-glucantime nanoassemblies effects on promastigote and amastigote of Leishmania major

The purpose of the present study was to design nanoassemblies of chitosan-titanium dioxide (TiO2) nanoparticles (NPs) loaded with glucantime for using their synergistic effects and enhancing the toxic effects of glucantime on Leishmania parasites. The nanoassemblies were prepared by electrostatic interactions and optimized by a response surface central composite design. The effects of glucantime, chitosan and TiO2 NPs amounts were studied on the particle size, zeta potential, loading efficiency, and release efficiency of drug from nanoassemblies. The conjugation of TiO2/chitosan-glucantime was verified by UV spectroscopy and changes in surface charge of NPs. The anti-promastigots effect of glucantime loaded in TiO2/chitosan nanoassemblies was studied by tripan blue dye test and their anti-amastigotes effect by counting the average number of parasites per infected J774 macrophages in 100 cells. The optimized formulation obtained by using 12.5 mg glucantime, 25 mg chitosan and 6 mg TiO2 NPs. Although TiO2 NPs alone were effective more than negative control in reduction of promastigots and amastigotes but they didn't show significant difference compared with free glucantime (p > 0.05). However, at the concentration of 50 μg/mL and after 72 h exposure nanoassemblies decreased the proliferation of L. major promastigotes and amastigotes 13 and 4-fold, respectively compared with glucantime alone. © 2017 Elsevier B.V

Acute and subchronic dermal toxicity of nanosilver in guinea pig

Silver has been used as an antimicrobial agent for a long time in different forms, but silver nanoparticles (nanosilver) have recently been recognized as potent antimicrobial agents. Although nanosilver is finding diverse medical applications such as silver-based dressings and silver-coated medical devices, its dermal and systemic toxicity via dermal use has not yet been identified. In this study, we analyzed the potential toxicity of colloidal nanosilver in acute and subchronic guinea pigs. Before toxicity assessments, the size of colloidal nanosilver was recorded in sizes <100 nm by X-ray diffraction and transmission electron microscopy. For toxicological assessments, male guinea pigs weighing 350 to 400 g were exposed to two different concentrations of nanosilver (1000 and 10,000 μg/mL) in an acute study and three concentrations of nanosilver (100, 1000, and 10,000 μg/mL) in a subchronic study. Toxic responses were assessed by clinical and histopathologic parameters. In all experimental animals the sites of exposure were scored for any type of dermal toxicity and compared with negative control and positive control groups. In autopsy studies during the acute test, no significant changes in organ weight or major macroscopic changes were detected, but dose-dependent histopathologic abnormalities were seen in skin, liver, and spleen of all test groups. In addition, experimental animals subjected to subchronic tests showed greater tissue abnormalities than the subjects of acute tests. It seems that colloidal nanosilver has the potential to provide target organ toxicities in a dose- and time-dependent manner