SOIL MITES AND NEMATODES COMMUNITY STRUCTURE IN A CONVENTIONAL AND NO-TILLAGE CHRONOSEQUENCE, COMPARED TO GRASSLANDS

Understanding the impact of long-term conventional tillage and no-tillage practices on soil biota is useful for estimating the level of disturbance in agroecosystems. An investigation was conducted in a long-term field experiment under no-till and conventional tillage management with a wheat-fallow rotation and in undisturbed grasslands, in the southwestern Canadian Prairies of Saskatchewan, at two different locations: Swift Current and Central Butte. The primary goal of the research was to compare the soil community structure of the nematodes and mites between long-term agro-management regimes and between long-term agro-management regimes and the native prairie land. After over 35 years of conventional tillage practices, both nematode and mite communities were negatively impacted. Thus, the increased soil disturbance (CT, conventional tillage) led to lower diversity and weaker soil nematode community structure than reduced soil disturbance (NT, no-till). The nematode maturity index (MI) revealed a more stable environment in the NT system. Oribatid mites dominated the soil mite community's relative density and genera diversity, regardless of agricultural management. Overall our results showed a positive relationship between crop rotation, reduced soil disturbance, and soil Acari's diversity and maturity in long-term agro-management regimes. Also, long-term agricultural practices (CT, NT) significantly altered the community structures of nematodes and mites compared to those from undisturbed grasslands. Thus, the highest number of identified nematode genera (68) was under native prairie (NP) systems. Nematode diversity and maturity decreased with the intensity of land cultivation. Farming impacted the diversity and community structure of Acari as well. Thus, the highest number of identified mites genera (53) was observed in NP systems, and the most mature community structure was also found in the grasslands. Oribatid mites dominated the soil mite communities in terms of relative density and genera diversity in agricultural land and in terms of diversity in the native prairies. A significantly higher proportion of Prostigmata was observed in grasslands, and a significantly lower proportion of Mesostigmata was attested in the CT system. Overall, the nematode and mites communities analysis affirmed that the tillage system significantly decreased the diversity of nematodes and mites, favoring a weaker organization of their communities. Consequently, their functional metabolic footprint had been severely altered compared to communities in native grasslands

Fiscal and Accounting Issues Concerning the Flat-Rate Tax and its Implications on the Business Environment in Romania

The introduction of flat-rate tax for companies is a novelty in the Romanian tax system, which is why businessmen' reactions were different, most of them criticizing harshly the opportunity for such a measure, arguing that during this crisis period for Romania, it may lead to the bankruptcy of tens of thousands of firms, consequently to an increase of the number of unemployed with several hundred thousands. Although the flat tax for natural persons has been applied for several decades, no legislation which has regulated this type of tax has given a definition of the flat-rate tax. Based on these considerations, in this paper we intend to address the theoretical and practical issues concerning the flat tax, in fiscal and accounting terms, together with its implications on the Romanian business environment.flat-rate tax, minimum tax, taxpayers, income, fiscal issues, accounting issues

Experimental Aspects for CeO2 Nanoparticles Synthesis and Characterization

In recent years, cerium oxide (CeO2, or ceria) became a versatile nanostructured material because of its unique properties derived from the low dimensionality and high surface area. It was also extensively studied due to its practical performances in many scientific and industrial applications, such as fuel cells, luminescent materials, gas sensors, insulators, white LEDs, etc. In this paper, the research focused on the synthesis and characterization of cerium oxide powder manufactured by the co-precipitation method, using inorganic cerium salt (Ce(NO3)3) and the precipitating agent (NaOH). In order to optimize the CeO2 particles synthesis process, the parameters of the process were monitored to obtain the quantitative precipitate and to optimize the heat treatment. The precursors type and concentration used, reaction temperature and time, the pH of reaction medium and order of the precipitating agent addition are the main factors influencing the particle size and morphology of cerium oxide nanoparticles. The physico-chemical properties of the cerium oxide nanoparticles were determined by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX). The FTIR spectrum of the CeO2 particles calcinated at 550 °C, in normal atmosphere, exhibits a strong band at 482 cm-1 corresponding to Ce-O stretching vibration. The XRD pattern confirmed the crystalline nature of the CeO2 nanoparticles with a cubic structure and average crystallite size around 15 nm. Moreover, EDX analysis confirms the presence of the Ce and O atoms corresponding to the theoretical formula. The morphology and microstructure were studied using SEM analysis

Infrared properties of the SDSS-maxBCG galaxy clusters

The physics of galaxy clusters has proven to be influenced by several processes connected with their galactic component which pollutes the ICM with metals, stars and dust. However, it is not clear whether the presence of diffuse dust can play a role in clusters physics since a characterisation of the IR properties of galaxy clusters is yet to be completely achieved. We focus on the recent work of Giard et al. (2008) who performed a stacking analysis of the IRAS data in the direction of several thousands of galaxy clusters, providing a statistical characterisation of their IR luminosity and redshift evolution. We model the IR properties of the galactic population of the SDSS-maxBCG clusters (0.1<z<0.3) in order to check if it accounts for the entire observed signal and to constrain the possible presence of other components, like dust in the ICM. Starting from the optical properties of the galaxy members, we estimate their emission in the 60 and 100 micron IRAS bands making use of modeled SEDs of different spectral types (E/S0, Sa, Sb, Sc and starburst). We also consider the evolution of the galactic population/luminosity with redshift. Our results indicate that the galactic emission, which is dominated by the contribution of star-forming galaxies, is consistent with the observed signal. In fact, our model slightly overestimates the observed fluxes, with the excess being concentrated in low-redshift clusters (z <~ 0.17). This indicates that, if present, the IR emission from intracluster dust must be very small. We obtain an upper limit on the dust-to-gas mass ratio in the ICM of Z_d <~ 5 10^-5. The excess in luminosity obtained at low redshift constitutes an indication that the cluster environment is driving a process of star-formation quenching in its galaxy members.Comment: 12 pages, 6 figures, 2 tables. Accepted for publication in A&

β-delayed γ-proton decay in 56Zn: analysis of the charged-particle spectrum

A study of the beta decay of the proton-rich T-z = 2 nucleus Zn-56 has been reported in a recent publication. A rare and exotic decay mode, beta-delayed gamma-proton decay, has been observed there for the first time in the fp shell. Here, we expand on some of the details of the data analysis, focussing on the charged particle spectrum

Fitting the integrated Spectral Energy Distributions of Galaxies

Fitting the spectral energy distributions (SEDs) of galaxies is an almost universally used technique that has matured significantly in the last decade. Model predictions and fitting procedures have improved significantly over this time, attempting to keep up with the vastly increased volume and quality of available data. We review here the field of SED fitting, describing the modelling of ultraviolet to infrared galaxy SEDs, the creation of multiwavelength data sets, and the methods used to fit model SEDs to observed galaxy data sets. We touch upon the achievements and challenges in the major ingredients of SED fitting, with a special emphasis on describing the interplay between the quality of the available data, the quality of the available models, and the best fitting technique to use in order to obtain a realistic measurement as well as realistic uncertainties. We conclude that SED fitting can be used effectively to derive a range of physical properties of galaxies, such as redshift, stellar masses, star formation rates, dust masses, and metallicities, with care taken not to over-interpret the available data. Yet there still exist many issues such as estimating the age of the oldest stars in a galaxy, finer details ofdust properties and dust-star geometry, and the influences of poorly understood, luminous stellar types and phases. The challenge for the coming years will be to improve both the models and the observational data sets to resolve these uncertainties. The present review will be made available on an interactive, moderated web page (sedfitting.org), where the community can access and change the text. The intention is to expand the text and keep it up to date over the coming years.Comment: 54 pages, 26 figures, Accepted for publication in Astrophysics & Space Scienc