493 research outputs found
DYNAMICS AND PRICE VOLATILITY IN FARM-RETAIL LIVESTOCK PRICE RELATIONSHIPS
This study uses an error correction model (ECM) to investigate dynamics in farm-retail price relationships. The ECM is a more general method of incorporating dynamics and the long-run, steady-state relationships between farm and retail prices than has been used to data. Monthly data for beef and pork are used to test the time-series properties for the ECM specification. The model is extended to study price volatility through the generalized autoregressive conditional heteroskedasticity (GARCH) process. Accommodation of the GARCH process provides a useful way of analyzing both mean and variance effects of policy or market structure changes.Demand and Price Analysis, Livestock Production/Industries,
Low-cost control problems on perforated and non-perforated domains
We study the homogenization of a class of optimal control problems whose state equations are given by second order elliptic boundary value problems with oscillating coefficients posed on perforated and non-perforated domains. We attempt to describe the limit problem when the cost of the control is also of the same order as that describing the oscillations of the coefficients. We study the situations where the control and the state are both defined over the entire domain or when both are defined on the boundary
Monthly and Diurnal Variability of Rain Rate and Rain Attenuation during the Monsoon Period in Malaysia
Rain is the major source of attenuation for microwave propagation above 10 GHz. In tropical and equatorial regions where the rain intensity is higher, designing a terrestrial and earth-to-satellite microwave links is very critical and challenging at these frequencies. This paper presents the preliminary results of rain effects in a 23 GHz terrestrial point-to-point communication link 1.3km long. The experimental test bed had been set up at Skudai, Johor Bahru, Malaysia. In this area, a monsoon equatorial climate prevails and the rainfall rate can reach values well above 100mm/h with significant monthly and diurnal variability. Hence, it is necessary to implement a mitigation technique for maintaining an adequate radio link performance for the action of very heavy rain. Since we now know that the ULPC (Up Link Power Control) cannot guarantee the desired performance, a solution based on frequency band diversity is proposed in this paper. Here, a secondary radio link operating in a frequency not affected by rain (C band for instance) is placed parallel with the main link. Under no rain or light rain conditions, the secondary link carries without priority radio signals. When there is an outage of the main link due to rain, the secondary link assumes the priority traffic. The outcome of the research shows a solution for higher operating frequencies during rainy events
EXPERIMENTAL INVESTIGATION ON CASCADED MULTILEVEL INVERTER USING SINGLE VOLTAGE SOURCE TOPOLOGY
This paper presents a cascaded H-bridge multilevel inverter with single DC source. Generally, each phase of the multilevel inverter requires ‘n’ number of DC sources for 2n+1 level. In this paper we have proposed a multilevel topology which requires only one DC source for all the three phases and other sources are replaced by ultra capacitors. Initially, the performance of multi level inverter has been studied by including all DC sources. Finally a single DC source is allowed and remaining n-1 DC sources are replaced by ultra capacitors. An adaptive PI controller is introduced for automatically maintaining the voltage level of capacitor and we use higher number of output levels to increase the quality of power. Comparison between both the cascaded multilevel inverter using DC source and ultracapacitor as source has been studied and it shows that the overall performance of ultracapacitor source is better than that of DC source. An experiment has been performed and the result shows that the proposed system is suitable for medium power applications
Dynamics and Long-Run Structure in U.S. Meat Demand
�Empirical analysis, based on a general dynamic Almost Ideal Demand System, shows the commonly used autoregressive and partial adjustment processes are restrictive to meal demand data. This study derives a linear specification in levels form to investigate dynamics in a general framework. Merging a long-run steady state structure with short-run dynamics results in consistent and robust long-run demand elasticities.
Dynamics and Long-run Structure in U.S. Meat Demand
Empirical analysis, based on a general dynamic Almost Ideal Demand System, shows the commonly used autoregressive and partial adjustment processes are restrictive to meat demand data. This study derives a linear specification in levels form to investigate dynamics in a general framework. Merging a long-run steady state structure with short-run dynamics results in consistent and robust long-run demand elasticities
Une analyse empirique, basée sur un systéme dynamique général de demande quasi optimale, montre que les mécanismes courants d\u27ajustement autorégressif et d\u27ajustement partiel ont un effect restrictif sur l\u27évaluation des données de la demande de viande. Les auteurs proposent une spécifcation linéaire par niveaux pour examiner la dynamique du cadre général. La combinaison d\u27une structure stable de longue durée avec une dynamique de courte période a produit des élasticités cohérentes et solides de la demande à long term
Inhibition of Vascular Smooth Muscle Cell Proliferation by Gentiana lutea Root Extracts
Gentiana lutea belonging to the Gentianaceae family of flowering plants are routinely used in traditional Serbian medicine for their beneficial gastro-intestinal and anti-inflammatory properties. The aim of the study was to determine whether aqueous root extracts of Gentiana lutea consisting of gentiopicroside, gentisin, bellidifolin-8-O-glucoside, demethylbellidifolin-8-O-glucoside, isovitexin, swertiamarin and amarogentin prevents proliferation of aortic smooth muscle cells in response to PDGF-BB. Cell proliferation and cell cycle analysis were performed based on alamar blue assay and propidium iodide labeling respectively. In primary cultures of rat aortic smooth muscle cells (RASMCs), PDGF-BB (20 ng/ml) induced a two-fold increase in cell proliferation which was significantly blocked by the root extract (1 mg/ml). The root extract also prevented the S-phase entry of synchronized cells in response to PDGF. Furthermore, PDGF-BB induced ERK1/2 activation and consequent increase in cellular nitric oxide (NO) levels were also blocked by the extract. These effects of extract were due to blockade of PDGF-BB induced expression of iNOS, cyclin D1 and proliferating cell nuclear antigen (PCNA). Docking analysis of the extract components on MEK1, the upstream ERK1/2 activating kinase using AutoDock4, indicated a likely binding of isovitexin to the inhibitor binding site of MEK1. Experiments performed with purified isovitexin demonstrated that it successfully blocks PDGF-induced ERK1/2 activation and proliferation of RASMCs in cell culture. Thus, Gentiana lutea can provide novel candidates for prevention and treatment of atherosclerosis
Use of a Distal Radius Endoprosthesis Following Resection of a Bone Tumour: A Case Report
Limited literature is available on the reconstruction of the distal radius using prosthetic replacement following resection of a bone tumour. We present the first reported case, in the English literature, of the use of an entirely metal endoprosthesis for the reconstruction of the distal radius. This case involves a 66-year-old male who was treated for giant cell tumour of the distal radius with surgical excision of the lesion and replacement of the defect using a predominantly titanium endoprosthesis. He was followed-up for 56 months following surgery and had a good functional outcome with no associated pain or complications. We propose that the use of a primarily titanium endoprosthesis for the reconstruction of a bone defect of the distal radius is a suitable alternative, providing good function of the forearm with satisfactory range of movement at the wrist and adequate pain relief
Phi-Meson Production at RHIC, Strong Color Fields and Intrinsic Transverse Momenta
We investigate the effects of strong color fields and of the associated
enhanced intrinsic transverse momenta on the phi-meson production in
ultrarelativistic heavy ion collisions at RHIC. The observed consequences
include a change of the spectral slopes, varying particle ratios, and also
modified mean transverse momenta. In particular, the composition of the
production processes of phi mesons, that is, direct production vs.
coalescence-like production, depends strongly on the strength of the color
fields and intrinsic transverse momenta and thus represents a sensitive probe
for their measurement.Comment: 4 pages, 3 figure
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