478 research outputs found
Impact of Risk within the Northern Ireland Dairy Sector
This paper examines farmersā decision making under risk and uncertainty. In particular, the study identifies the type of risk preference (averse, neutral or seeking) and measures the magnitude of risk preference before and after the introduction of the Single Farm Payment (SFP). The analysis therefore provides an insight into the impact of this fundamental policy change on farmer risk behaviour. Furthermore, it examines agricultural production decision making under price uncertainty. Empirically, it evaluates the impact of risk and uncertainty using Farm Business Survey (FBS) data of NI dairy farms. Using an econometric approach (maximize expected utility), a comprehensive methodology is employed that enables price uncertainty and risk preference under the Common Agricultural Policy (CAP) to be analysed simultaneously. The methodology permits the testing of common risk aversion theoretical hypotheses, including Arrowās hypothesis on the effect of wealth on the measures of risk aversion. Also, this methodology enables the identification of the impact of farmersā attitude to risk, price uncertainty and other criteria (e.g. age, education, and family labour) on their production decisions. The results are relevant to both policy makers and farmers. With regards to the former, the results reveal the factors which influence famersā decision making, therefore, enabling policy makers to evaluate the effectiveness and efficiency of agricultural policies and thus introduce improvements in future policies. With regards to farmers, the results demonstrate the consequences of risk and uncertainty on their operational environment.Agricultural and Food Policy,
The phase transition of higher dimensional Charged black holes
In this paper,we have studied phase transitions of higher dimensional charge
black hole with spherical symmetry. we calculated the local energy and local
temperature, and find that these state parameters satisfy the first law of
thermodynamics. We analyze the critical behavior of black hole thermodynamic
system by taking state parameters of black hole thermodynamic
system, in accordance with considering to the state parameters of Van
der Waals system respectively. we obtain the critical point of black hole
thermodynamic system, and find the critical point is independent of the dual
independent variables we selected. This result for asymptotically flat space is
consistent with that for AdS spacetime, and is intrinsic property of black hole
thermodynamic system.Comment: 15 pages,14 figures,references adjuste
Existence of periodic solutions for first-order delay differential equations via critical point theory
A Stochastic Analysis of the Impact of Volatile World Agricultural Prices on European and UK Agriculture
Successive Common Agricultural Policy (CAP) reforms and trade liberalisation have led to a more market-orientated European agricultural sector, with EU commodity prices now more closely linked to world prices. As a consequence EU prices have become more volatile. Greater price volatility increases uncertainty and raises fresh challenges for projections of policy impacts in the EU. To take account of world price volatility stochastic modelling has been applied to the FAPRI-EU partial equilibrium model, which includes a UK modelling system. Stochastic modelling provides a means to capture some of the inherent uncertainty associated with agricultural production systems. By varying assumptions about certain exogenous variables, stochastic models can be used to examine the different ways markets may behave. Variable world prices are incorporated within the EU GOLD model. This process identifies the impact of a stochastic distribution of world prices on EU agriculture rather than the single point estimates in the conventional deterministic approach. The results outlined in this study demonstrate the impact of volatile world prices on EU and, in particular, UK prices and market control instrumentsAgricultural policy, Stochastic modelling, Agricultural and Food Policy,
Finite element linear static structural analysis and modal analysis for Lunar Lander
Lunar exploration is one of the most important projects in the world. A primary objective of the probe in lunar is to soft-land a manned spacecraft on lunar surface. The soft-landing system is the key composition of the lunar lander. In the overall design of lunar lander, the analysis of touchdown dynamics during landing stage is an important work. In this paper, firstly, based on the mechanical theory, a finite element model for the lunar lander is established. Secondly, the linear static structural analysis under particular conditions is performed to determine the nodal stress and displacement distributions and the modal analysis is conducted to obtain the frequencies and their corresponding vibration shapes. Finally, the weakness parts of the structure and the behavior of the system are obtained by analyzing the simulating results, which are beneficial to the optimizing design for the lunar Lander
Hopanoids Play a Role in Membrane Integrity and pH Homeostasis in Rhodopseudomonas palustris TIE-1
Sedimentary hopanes are pentacyclic triterpenoids that serve as biomarker proxies for bacteria and certain bacterial metabolisms, such as oxygenic photosynthesis and aerobic methanotrophy. Their parent molecules, the bacteriohopanepolyols (BHPs), have been hypothesized to be the bacterial equivalent of sterols. However, the actual function of BHPs in bacterial cells is poorly understood. Here, we report the physiological study of a mutant in Rhodopseudomonas palustris TIE-1 that is unable to produce any hopanoids. The deletion of the gene encoding the squalene-hopene cyclase protein (Shc), which cyclizes squalene to the basic hopene structure, resulted in a strain that no longer produced any polycyclic triterpenoids. This strain was able to grow chemoheterotrophically, photoheterotrophically, and photoautotrophically, demonstrating that hopanoids are not required for growth under normal conditions. A severe growth defect, as well as significant morphological damage, was observed when cells were grown under acidic and alkaline conditions. Although minimal changes in shc transcript expression were observed under certain conditions of pH shock, the total amount of hopanoid production was unaffected; however, the abundance of methylated hopanoids significantly increased. This suggests that hopanoids may play an indirect role in pH homeostasis, with certain hopanoid derivatives being of particular importance
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