Transformation and loss of excretal nitrogen under winter management systems : a thesis submitted in partial fulfilment of the requirements for the degree of Master of Science in Soil Science at Massey University, Palmerston North, New Zealand

Excreta from cattle animals contain large amounts of nutrients, particularly nitrogen, which could lead to substantial gaseous losses of ammonia and nitrous oxide to the atmosphere, as well as nitrogen leaching. These losses are greatest during wet conditions in winter. However, the situation could be improved through moving cows off grazing paddocks to a stand-off pad or housing system. Therefore, it is necessary to quantify ammonia emissions and evaluate denitrification potential (which leads to emission of N₂O) through various winter management systems in order to determine methods and technologies for efficient and effective mitigation of gaseous emissions. To understand the mechanism of nitrogen transformation and of reduction on gaseous emission from excreta in various winter management systems, a series of incubation studies and a field study were carried out investigating the suitability of several natural materials with absorbent properties, as media to reduce gaseous emission of ammonia and nitrous oxide. The incubation studies were undertaken using cow excreta that consisted of a 1:1 (v:w) mixture of fresh urine and dung collected from a dairy farm. A lab incubation study was conducted using excreta, and excreta amended with soil and sawdust treatments. A further lab incubation study was carried out using different levels of natural materials. The field study consisted of two stand-off pads in which crushed pine bark or sawdust were used as bedding materials. In the incubation study, ammonification was rapid in the case of excreta, compared to excreta amended with addition of natural materials. Whereas nitrification was very slow in the all treatments, only a small amount of nitrate ions could be detected till the end of incubation study. In the incubation study, both soil and sawdust appeared to significantly reduce ammonia emission. In comparison to excreta, amendment with soil (excreta: soil=1:2, w:w) and sawdust (excreta: sawdust=1:2, w:v) reduced ammonia loss by 32.9% and 19.5%, respectively. Excreta amended with a combination of soil and sawdust (1:1:1, w:w:v) was most effective, reducing ammonia emission by 34% under aerobic conditions. Nitrate concentration was found to be the crucial limiting factor affecting the denitrification rate in the incubation studies. When KNO₃ was added to the excreta, the denitrification rate was 43.8µg N₂O-N/g excreta/hour. However, the denitrification rate of the excreta amended with both glucose-C and KNO₃ was 114.4µg N₂O-N/g excreta/hour. Denitrification potential followed: excreta> excreta with sawdust> excreta with soil. On a field-scale stand-off pad, the carbon-rich natural materials pine bark and sawdust were shown to retain nitrogen effectively. After nine months of use, the bark retained 78% of the deposited excreta-N, while the sawdust pad retained 51%. Therefore, it can be concluded that reduction of nitrogen losses can be achieved by using stand-off pad or housing systems (herd homes) which incorporate the use of a carbon rich natural material or soil in winter

Numerical analysis of subsoil-reinforced concrete slab interaction

This article presents the numerical modeling of interaction between a reinforced concrete slab and subsoil using ABAQUS. Subsoil was simulated as both homogeneous half-space and inhomogeneous half-space. Reinforcement bars in the concrete slab were accurately modelled allowing capturing a precise deformation profile of the slab in interaction with subsoil. Input data for numerical analysis were adopted from a published work. Results of the study were verified on the basis of comparison with those of the previous study

The experience of segmenting the inbound tourist flow from china to Russia

The recent increase in the outbound tourist flow from China, this research topic is becoming actual. The author of the article is analyzing the Chinese tourist flow and breaking it into segments by age in order to identify problems in attracting Chinese tourists to Russia and to provide relevant recommendations.В связи с ежегодным увеличением выездного туристского потока из Китая актуальными становятся исследования на данную тему. Автор статьи ставит задачей проанализировать китайский турпоток и провести его сегментирование по возрасту для того, чтобы выявить проблемы по привлечению китайских туристов в Россию и дать уместные рекомендации по их решению

Untersuchungen zur Bedeutung der intrazellulären Ca2+ Konzentration für die Chemotaxis von Seeigel- und Seestern-Spermien

The events that occur during chemotaxis of sperm are only partly known. As an essential step toward determining the underlying mechanism, we developed a sensitive laser-stroboscopic technique that allows the recording of changes in intracellular Ca$^{2+}$-concentration in swimming sperm of the sea urchin Arbacia punctulata and starfish Asterias amurensis. Stimulation of the sea urchin Arbacia punctulata by the themoattractant or by intracellular cGMP evokes Ca$^{2+}$ spikes in the flagellum. These Ca$^{2+}$ spikes control the swiming behaviour of sperm. A Ca$^{2+}$ spike elicits a turn in the trajectory followed by a period of straight swimming (‘turn-andrun’). The train of Ca$^{2+}$ spikes gives rise to repetitive loop-like movements. When sperm swim in a concentration gradient of the attractant, the Ca$^{2+}$ spikes and the stimulus function are synchronized, suggesting that precise timing of Ca$^{2+}$ spikes controls navigation. We identified the peptide asterosap as a chemotactic factor of the starfish Asterias amurensis. The similarities in first, the cGMP-induced Ca$^{2+}$ spikes in the flagellum, second, the motor response and third the swimming behavior of sperm from starfish and sea urchin imply that the signaling pathway of chemotaxis has been conserved in species, which diverged almost 500 million years ago. A cGMP-gated ion channel (CNG-channel), which might be involved in hyperpolarisation or Ca$^{2+}$ entry, could not yet be identified in Arbacia punctulata. Voltage-sensitive Ca$^{2+}$- channels, which are only said to have a function in the acrosome reaction, however, seem to play a more important role for the Ca$^{2+}$ entry during sperm chemotaxis

Uncertainty in an Interconnected Financial System, Contagion, and Market Freezes

This paper studies contagion and market freezes caused by uncertainty in financial network structures and provides theoretical guidance for central banks. We establish a formal model to demonstrate that, in a financial system where financial institutions are interconnected, a negative shock to an individual financial institution could spread to other institutions, causing market freezes because of creditors' uncertainty about the financial network structure. Central bank policies to alleviate market freezes and contagion, such as information policy, bailout policy and the lender of last resort policy, are examined