Competition and Predation in Soil Fungivorous Microarthropods Using Stable Isotope Ratio Mass Spectrometry

The soil food web is often described as having three main energy channels: root, bacterial and fungal. Here we provide quantitative data using a sensitive stable isotope ratio mass spectrometry procedure with microcosms on species interactions in the fungal pathway. We measured 15N and 13C enrichment in microarthropods through grazing rare isotope enriched fungal mycelia. Experimental treatments were various combinations of 1, 2, 3, 4 microarthropods species. We used three fungivores (the collembolan Lepidocyrtus curvicollis, the Astigmata Tyrophagus putrescentiae, the Oribatida Oribatula tibialis.), and the Mesostigmata predator Hypoaspis acquilifer We collected individuals of each species separately, as well as their faeces, and moult where available. All three fungivorous microarthropods consumed significantly more than their own body weight per day. The three fungivores differed in their consumption of the mycelium as it was not equally palatable to each. The Mesostigmata predator Hypoaspis also differed in its microarthropod prey preference. In multiple species combinations microarthropod behavioural interactions modified consumption and predation rates. Our selection of mites of different sizes, with varied preference for the mycelium, combined with differing predation rates on each mite, demonstrate that even three trophic level interactions with only five interacting species are not predictably simple. The interpretation of the stable isotope results and consumed-excreted weights indicate that: a) behaviour and microscopic observations should not be ignored in competition-predation interactions, and b) functional guilds can take advantage of more diverse food opportunities. The reality of mixed diets complicates functional guild assignments that are reflected in 15N and 13C isotope levels at natural abundances in the environment. Microcosm experiments with this sensitive technique can help decipher the interpretation of rare isotope natural abundance values, as well as providing measured consumption, growth, and excretion rate values for modelling soil food web interactions

Phosphorous recovery from key pyrolyzates

Non-Peer ReviewedThe exploitation of phosphorus (P) ore for soil fertilization supports the high demand of modern agriculture, but limitations of P sources encourage research in sustainable P use, recovery and reuse. Here we propose the integration of pyrogenic carbon (i.e. biochar) production into waste management systems for phosphorus (P) reuse and recovery by pyrolysis (PRP). A meta-analysis indicated animal manure, human excreta, and plant-biomass collected from P polluted sites to be sources of P-enriched biomass, all of which have been examined as feedstocks for biochar. As a soil amendment, biochar could serve to both supply P and reduce P loss. The release, sorption and desorption of P by biochar will codetermine the potential of P replenishment by biochar and P loss from biochar-amended soils. Factors such as pH, metal content, colloidal-sized particles, and activities of soil biota (arbuscular mycorrhizal fungi and phosphorous solubilizing microorganisms) are expected to affect sorption- desorption of P between biochar and soil aggregates and P acquisition by plants. Phosphorus in biochar is expected to participate in P equilibrium in soil. Chemical extraction, using acid or alkaline solutions, is considered as a means for P retrieval from high P biochar, especially for biochars with high heavy metal contents. To bridge the gap between academia and practice, this paper stresses key objectives for PRP: 1) identification of key biomass for pyrolysis; 2) retrieval of P from biochar in soils or by chemical leaching; 3) biochar modification by inorganic nutrients, P solubilizing microorganisms and other organic matter; and 4) compatible pyrolysis equipment fit to the current waste management context, such as waste water plants

Steel Case Hardening Using Deformational cutting

This article describes some fundamental principles, specific features and the technological capabilities of a new method of quenching steel surface by turning without separation of chips. The underlying process of this method is a deformational cutting which is based on the undercutting and deformation of surface layers that remain attached to the workpiece. The energy released in the area of deformational cutting is used to heat the undercut layer up to the temperatures of structural and phase transformation of workpiece material. This type of process results into a hardened structure formed at the surface which consists of inclined thin undercut layers tightly packed and stuck (glued) together and form a single solid body. The resulting hardened structures achieved in steels workpieces are presented in the article. The samples hardened by deformational cutting showed a higher wear resistance compared to samples with traditional quenching. This paper also describes an estimation of the thermo-physical parameters of the deformational cutting process

Free-living nitrogen fixation in Saskatchewan agriculture

Non-Peer Reviewe

A Study of Sliding Friction Using an Acoustic Emission and Wavelet-Based Energy Approach

The purpose of this work is to study the mechanism of running-in during friction and to determine the informative parameters characterizing the degree of its completion. During friction, contact interaction of rough surfaces causes various wave phenomena covering a wide range of frequencies, the subsequent frequency analysis can provide information about the sizes of wave sources and thereby clarify the mechanism of interaction between surface roughness. The using of the wavelet transform for processing the signals of audible acoustic emission made it possible to determine the beginning and the end of the change in the frequency ranges of the interaction of roughness. The code developed by the authors was used to analyze the acoustic emission signals by using wavelet energy and entropy criteria. The mother wavelet was chosen by carefully evaluating the effectiveness of 54 preliminary candidates for the mother wavelet from 7 wavelet families, according to three criteria: (1) maximum wavelet energy; (2) Shannon entropy minimum; and (3) maximum energy-to-Shannon entropy ratio

High Performance Computing Applications in Remote Sensing Studies for Land Cover Dynamics

Global and regional land cover studies require the ability to apply complex models on selected subsets of large amounts of multi-sensor and multi-temporal data sets that have been derived from raw instrument measurements using widely accepted pre-processing algorithms. The computational and storage requirements of most such studies far exceed what is possible on a single workstation environment. We have been pursuing a new approach that couples scalable and open distributed heterogeneous hardware with the development of high performance software for processing, indexing, and organizing remotely sensed data. Hierarchical data management tools are used to ingest raw data, create metadata, and organize the archived data so as to automatically achieve computational load balancing among the available nodes and minimize I/O overheads. We illustrate our approach with four specific examples. The first is the development of the first fast operational scheme for the atmospheric correction of Landsat TM scenes, while the second example focuses on image segmentation using a novel hierarchical connected components algorithm. Retrieval of global BRDF (Bidirectional Reflectance Distribution Function) in the red and near infrared wavelengths using four years (1983 to 1986) of Pathfinder AVHRR Land (PAL) data set is the focus of our third example. The fourth example is the development of a hierarchical data organization scheme that allows on-demand processing and retrieval of regional and global AVHRR data sets. Our results show that substantial improvements in computational times can be achieved by using the high performance computing technology

The effect of quince leaf (Cydonia oblonga miller) decoction on testes in hypercholesterolemic rabbits: A pilot study

Current medical literature lacks any evidence of the protective effects of quince leaf on testes. Therefore, the aim of the present study was to assess the effect of quince (Cydonia oblonga Miller) leaf decoction on testicular injury and impaired spermatogenesis induced by hypercholesterolemia in rabbits. Eleven mature New Zealand white male rabbits were randomly divided into three groups: group 1 (hypercholesterolemia, n=3), group 2 (hypercholesterolemia plus quince treatment, n=6), and group 3 (control, n=2). Groups 1 and 2 received a cholesterol-enriched diet for six weeks. Group 2 received C. oblongaleaf decoction as drinking supplement as well. After six weeks, a normal diet was substituted in groups 1 and 2 for another six weeks. Group 3 (control group) was maintained throughout the study on a regular diet. At the end of the 12th week, the left testes of the animals were resected for light microscopic study with particular attention to the maturity of germ cells in seminiferous tubules using Johnsen’s score. Increase in intertubular connective tissue and diameter of vessels, abundant spermatogonia and primary spermatocytes along the reduced germinal epithelium were noted in all rabbits of the group 1. The remaining animals in groups 2 and 3 had no significant changes in their testicular sections. The mean Johnsen’s score of group 1 (4.20±1.92) was significantly lower than that of group 2 (7.33±0.52) and group 3 (7.05±0.07). (P=0.01). Inconclusion, quince leaf decoction (C. oblonga Miller) protected rabbit testes and spermatogenesis from damage induced by hypercholesterolemia

Research and automation of the process of electrocoagulation wastewater treatment on the basis of the developed mathematical model

The paper presents the principles of the construction of an automated wastewater treatment system based on a generalized spatial model. A model problem, which contains descriptions of the main processes occurring in the electrocoagulation reactor taking into account the placement of the plates was developed. To verify the adequacy, a comparison between computer simulations and the results of a field experiment was made. The influence of reactor size, current density, location of electrode plates on the efficiency of chromium extraction was investigated. As a result of the study, it was proved that the mathematical model is effective for determining the parameters of the purification process, and the obtained coefficients are effective for optimizing the purification process. Based on these studies, a scheme for automation of the process of wastewater treatment from chromium was built. With the help of SCADA - WinCC, a flexible control system with the ability to control the performance of the entire installation in real time was developed