2,526 research outputs found

    The physics and kinematics of the evolved, interacting planetary nebula PN G342.0-01.7

    Full text link
    Here we aim to study the physical and kinematical characteristics of the unstudied old planetary nebula (PN) PN G342.0-01.7, which shows evidence of interaction with its surrounding interstellar medium. We used Integral Field Spectra from the Wide Field Spectrograph on the ANU 2.3 m telescope to provide spectroscopy across the whole object covering the spectral range 3400-7000 {\AA}. We formed narrow-band images to investigate the excitation structure. The spectral analysis shows that the object is a distant Peimbert Type I PN of low excitation, formally of excitation class of 0.5. The low electron density, high dynamical age, and low surface brightness of the object confirm that it is observed fairly late in its evolution. It shows clear evidence for dredge-up of CN-processed material characteristic of its class. In addition, the low peculiar velocity of 7 km s1^{-1} shows it to be a member of the young disk component of our Galaxy. We built a self-consistent photoionisation model for the PNe matching the observed spectrum, the Hβ\beta luminosity, and the diameter. On the basis of this we derive an effective temperature logTeff5.05\log T_{\rm eff} \sim 5.05 and luminosity 1.85<logL<2.251.85 < \log L < 2.25. The temperature is much higher than might have been expected using the excitation class, proving that this can be misleading in classifying evolved PNe. PN G342.0-01.7 is in interaction with its surrounding interstellar medium through which the object is moving in the south-west direction. This interaction drives a slow shock into the outer PN ejecta. A shock model suggests that it only accounts for about 10\% of the total luminosity, but has an important effect on the global spectrum of the PN.Comment: 15 pages, 6 figures, A&A accepted 201

    TOPSIS Approach for Solving Bi-Level Non-Linear Fractional MODM Problems

    Get PDF
    TOPSIS (technique for order preference similarity to ideal solution) is considered one of the known classical multiple criteria decision making (MCDM) methods to solve bi-level non-linear fractional multi-objective decision making (BL-NFMODM) problems, and in which the objective function at each level is considered nonlinear and maximization type fractional functions. The proposed approach presents the basic terminology of TOPSIS approach and the construction of membership function for the upper level decision variable vectors, the membership functions of the distance functions from the positive ideal solution (PIS) and of the distance functions from the negative ideal solution (NIS). Thereafter a fuzzy goal programming model is adopted to obtain compromise optimal solution of BL-NFMODM problems. The proposed approach avoids the decision deadlock situations in decision making process and possibility of rejecting the solution again and again by lower level decision makers. The presented TOPSIS technique for BL-NFMODM problems is a new fuzzy extension form of TOPSIS approach suggested by Baky and Abo-Sinna (2013) (Applied Mathematical Modelling, 37, 1004-1015, 2013) which dealt with bi -level multi-objective decision making (BL-MODM) problems. Also, an algorithm is presented of the new fuzzy TOPSIS approach for solving BL-NFMODM problems. Finally, an illustrative numerical example is given to demonstrate the approach

    SOME GENETIC ASPECTS IN TWO STRAINS OF CHICKEN AND THEIR CROSSES

    Get PDF

    Random sampling vs. exact enumeration of attractors in random Boolean networks

    Full text link
    We clarify the effect different sampling methods and weighting schemes have on the statistics of attractors in ensembles of random Boolean networks (RBNs). We directly measure cycle lengths of attractors and sizes of basins of attraction in RBNs using exact enumeration of the state space. In general, the distribution of attractor lengths differs markedly from that obtained by randomly choosing an initial state and following the dynamics to reach an attractor. Our results indicate that the former distribution decays as a power-law with exponent 1 for all connectivities K>1K>1 in the infinite system size limit. In contrast, the latter distribution decays as a power law only for K=2. This is because the mean basin size grows linearly with the attractor cycle length for K>2K>2, and is statistically independent of the cycle length for K=2. We also find that the histograms of basin sizes are strongly peaked at integer multiples of powers of two for K<3K<3

    Development of chitosan-glucose and chitosan-citric complexes edible coating to improve tomatoes post-harvest quality

    Get PDF
     The effect of different shrimp chitosan molecular weights as well as shrimp chitosan complexes (chitosan-glucose and chitosan-citric) on the quality characteristics of the stored (at 7°C±2°C and 90% RH) tomato fruits (Lycopersicum esculentum) was investigated.  Coating tomatoes with high molecular weight chitosan (H.M.C.G) significantly improved firmness and weight loss.  The lowest weight loss was found in high molecular weight chitosan-glucose (H.M.C.G) treatment followed by the fruits coated with high molecular weight chitosan (HMC) and then uncoated tomato fruits.  Both molecular weights was clear on retarding the total acidity loss especially for stored tomato fruit coated with low molecular weight chitosan, while control tomatoes exhibited a larger reduction (p ≤ 0.05) in total acidity over storage.  Meanwhile, the increasing of cold storage time significantly (p ≥ 0.05) increased the pH in all uncoated and coated tomatoes.  Generally, no significant (P > 0.05) difference was observed in pH, titratable acidity and total soluble solids (T.S.S.) as well as sensory attributes among the tomato fruits coated with chitosan, chitosan citric and chitosan glucose.  Meanwhile, the fruits coated with low molecular weight chitosan had a higher (p ≥ 0.05) T.S.S. compared with that coated by the high molecular weight chitosan.   Keywords: chitosan, edible coating, tomatoes, firmness and weight loss

    Mechanism of action of liver growth induced by peroxisome proliferators

    Get PDF
    Humans are ubiquitously exposed to peroxisome proliferators including hypolipidemic agents, industrial solvents and atural products. Because of this and the fact that peroxisome proliferators cause non-genotoxic hepatocarcinogenesis in rodents, it is of importance to elucidate the mechanism of action of the peroxisome proliferators in order to provide an assessment of the hazard, if any, of these compounds to humans. It is also known that the peroxisome proliferators begin their actions by inducing hepatic DNA synthesis. Thus, the aim of this thesis was to find genes that could be responsible for triggering the induction of hepatic DNA synthesis caused by peroxisome proliferators, specifically ciprofibrate. First, it was important to indicate when the induction of hepatic DNA synthesis actually happens. This was done with BrdU immunohistochemical procedures. The induction of hepatic DNA synthesis with ciprofibrate in mice was observable only after 4 days making it difficult to specify when the induction actually happened. In rats the induction of hepatic DNA synthesis was found to peak at 24 hours and this system gave the better opportunity to find the genes responsible. The difference in the timing of induced hepatic DNA synthesis betweenmice and rats implied that there could be a species difference in the mechanism of each species’ response to PPAR. With immunohistochemistry it was noticed that there was a difference in the lobular localization of hepatic DNA synthesis in the liver tissues of rats and mice dosed with different inducers, with the rat livers exhibiting periportal distribution while hepatic DNA synthesis in the mice seemed to be distributed throughout the liver tissue. The effects of ciprofibrate or cyproterone acetate on liver gene expression in rats were studied, using cDNA microarrays, transcriptome sequencing and quantitative real- time PCR. A 1- 5 hour treatment period was chosen to detect the immediate early gene response, while a 24 hour time point was chosen to elucidate the confounding effects from the hepatic DNA synthesis seen during the 24 hour stimulation. The results showed that ciprofibrate altered the expression of numerous genes including previously known PPARa agonist-responsive genes involved in processes such as PPAR signalling pathways, fatty acid metabolic pathway, cell cycle, palmitoyl-CoA hydrolase activity, lipid metabolism, inflammatory responses, and stress responses, in addition to a large number of novel candidate genes. Three novel induced genes G0s2, Ccnd1 and Scd1, (and two marker genes CYP4A1 and CYP3A1) were confirmed with quantitative real- time PCR. The G0s2, Ccnd1 and Scd1 were found to be up-regulated at the hours 1 and 3 after dosing and not 24 hours, and the G0s2 and Scd1 were specific for the ciprofibrate suggesting they were involved in a distinct PPARa pathway responsible for the hepatic DNA synthesis. The complete database of the transcriptional response provided here opens doors of opportunity for further research to identify genes responsible for the liver growth induced by peroxisome proliferators

    Guidelines for data collection on energy performance of higher-education buildings in Egypt: a case study

    Get PDF
    Reliable energy analysis of buildings relies heavily on high-quality data leading to proper indicators. Previous studies have highlighted the importance of data quality in analyzing energy usage in residential and non-residential buildings in order to transform declarations to actions, optimise energy efficiency policies and monitor progress and failures in countries. Collected data must adhere to national and international standards for energy performance in buildings. This study aims to provide practical guidelines for effectively collecting and preparing data suitable for evaluating energy performance in Egyptian higher-education (HE) buildings. The guidelines are developed based on a comprehensive case study, considering data availability in typical educational facilities. Architectural and civil engineering drawings, construction specifications, and occupancy details are accessible. However, actual monthly electrical and natural gas consumption data for individual buildings are lacking. To address this, the study proposes the creation of detailed datasheets for each building, encompassing all energy sources and their electrical and power specifications, such as equipment, machinery, and HVAC systems. These datasheets were utilized to calculate energy consumption and energy usage indicators (EUI). The findings demonstrate that the datasheets enable adequate assessment of energy usage in various spaces within educational buildings, including staff rooms, lecture halls, and laboratories. This facilitates the identification of areas in need of targeted energy efficiency improvements. Notably, the study reveals that electricity consumption in the Faculty of Engineering building is significantly influenced by PCs, laboratories, lighting, and air conditioning
    corecore