171 |
Caffeine Supplementation and Moderate Intensity Exercise Modulates the Cytotoxic Lymphocyte Subset (CD+8) in NaIve and Tolerant IndividualsFedor, Elizabeth Ann 01 December 2010 (has links)
The purpose of this investigation was to determine the effects of caffeine supplementation on caffeine tolerant and caffeine naïve individual’s lymphocyte counts, apoptosis and migration levels. In addition, effects of exercise on post-caffeine ingestion lymphocyte counts, apoptosis and migration levels were determined. It was hypothesized that caffeine would alter the immune system cell counts, but that exercise would be able to restore the immune system to homeostasis. Seventeen Western Kentucky University students were tested (males n=7, females n=10; n=7: caffeine tolerant= 200mg or more per day group, n=9: caffeine naïve= 50mg or less per day group). In this double-blind investigation, all participants completed two exercise bouts: 30 min of treadmill running at 60-80% HRR once with a placebo drink before exercise and once with 6 mg/kg body weight of caffeine drink completed in a counterbalanced manner. Blood was taken at rest, 30 min after drink ingestion, immediately post exercise, and 60 min post exercise. Blood was stained with antibody markers (Annexin V to determine apoptotic cell counts, CX3CR1 to determine cell migration, CD4=helper T cells, CD8=cytotoxic T cells, CD19=B cells). Blood was analyzed using flow cytometry. We found that cytotoxic T cells showed significant increases following the caffeinated run in both groups combined (tolerant and naïve, p=0.001) and specifically in the naïve group on the caffeine run (p=.004). We did not see any significant changes in CD4, or CD19 cell counts. There were no significant changes in CD4, CD8 or CD19 cell migration or apoptosis. Our results showed that caffeine supplementation causes an increased effect on cytotoxic T cells counts when combined with exercise, and this effect was greater for the caffeine naïve group. The combined effects of caffeine and exercise may have elevated the plasma catecholamine and cortisol levels which are associated with immune cell function and movement. CD8 cells have a greater density of β-receptors, which are influenced by catecholamine, and may explain the increase in their cell counts compared to CD4 and CD19.
|
172 |
Panic Attack: A Comparative Analysis of United States Bank PanicsCain, Cameron J. 01 January 2012 (has links)
Through-out the history of the United States, there have been many bank panics starting with the first one in 1819. I use important data from bank panics which happened prior to 1934 to shed light on the most recent Panic of 2007. This data analysis will not only be important to explain the Panic of 2007, but will be essential to help provide insights to what can be done to remedy the situation. Even in 2012, the United States is still feeling the impact of what happened in 2007. Therefore by understanding history and analyzing the past, solutions to prevent future panics can be implemented.
|
173 |
Economic Analysis of the North American Softwood Lumber MarketsShahi, Chander Kamal 01 August 2008 (has links)
Markets have an important role to play in advancing an improved understanding of international trading relationships. Two most important economic issues, which contribute to improved national welfare and ensure long-run competitive market equilibrium in international markets, are market integration and market efficiency. To provide softwood lumber markets related information to the policy makers, economic analyses relating market integration and market efficiency of the combined markets of Canada and the US have been conducted. The economic analyses include: (i) testing cointegration of prices among North American softwood lumber markets; (ii) identifying price leading markets in long-run price structure of these cointegrated markets; (iii) examining the degree of market integration among these markets; and (iv) testing the efficiency of spatial arbitrage among these markets.
First, the price linkages in the North American softwood lumber markets have been explored over different trade regimes. The results indicate that market integration is affected by product aggregation of data. Further investigations of market integration are, therefore, limited to homogeneous softwood lumber product markets. Second, oligopsonistic pricing behavior of traders is identified as the possible reason for imperfect competition among Douglas Fir product markets, while imperfect competition among the markets of Spruce-Pine-Fir and Hem Fir products can not be explained by this behavior. Third, a comprehensive picture of the adherence to price parity is formulated by evaluating the magnitude and persistence of deviations from equilibrium relation of prices. It is found that large volumes of trade, product substitutability, lower prices, and certainty of trade are the factors which contribute to higher degree of market integration among North American softwood lumber product markets. Finally, the inter-temporal shifts in regime probabilities of competitive market equilibrium are assessed over different trade regimes. It is found that lower transaction costs, large volumes of trade, short distances between markets, and certainty of trade contribute to high market efficiency among softwood lumber product markets of North America.
|
174 |
Production and behaviour of four strains of laying hens kept in conventional cages and a free run systemSingh, Renu 05 1900 (has links)
Production, egg quality, behaviour, and physical condition were compared from Wk 20 to Wk 50 among three beak- trimmed commercial laying strains, Lohmann White (LW), H & N White (HN), Lohmann Brown (LB), and a non-commercial Cross between Rhode Island Red (male) and Barred Plymouth Rock (female) in conventional cages and in floor pens. All chicks were reared in their respective environments, and 450 and 432 pullets were housed at 18 and 7 weeks of age in cages and floor pens respectively. Hens in cages were provided with 688 cm2/bird and those in pens with over 6,000 cm2/bird, both of which are more than provided by commercial standards.
Body weights and eggshell weights were higher for birds in floor pens than those in cages, and although they increased with age, body weight of hens in cages decreased at Wk 50. White-egg layers (LW, HN) used perches and nest boxes more than Brown-egg layers (LB, Cross). During the laying period, mortality was higher for all strains in cages and during the rearing period mortality was higher in floor pens for LB hens but not other strains. No aggressive behaviours were found, but the frequency of gentle feather pecking and pecking at the enclosure was higher in cages than in floor pens.
Feather condition deteriorated over time in cages mainly because of contact with the cage wires whereas in floor pens, feather condition of birds at Wk 20 was not different from that at Wk 50. The frequency of keel bone deformities was higher for White-egg layers than for Brown-egg layers in cages and was higher for Cross hens than other strains in floor pens. Claws were longer in cages than in the floor pens. Foot condition was worse in floor pens than in cages.
The welfare indicators used in this study showed that cages restricted the hens' behaviour compared to floor pens and resulted in higher laying period mortality, reduced body weight and deteriorated feather condition than floor pens. Both systems had advantages and disadvantages in regard to the hens’ health and welfare. The use of environmental complexities was strain specific in floor pens. The environment by genotype interactions suggests that the strain should be considered when considering alternative housing systems.
|
175 |
Third party logistics in Chinese automotive industry : a case study of a Chinese automotive manufacturer-Shanghai General MotorsZhang, Luying, Hou, Zhaoyu, Qiu, Xiaoying January 2012 (has links)
In today’s Chinese automotive industry, the traditional self-management logistics mode cannot fulfill higher requirement of logistics performance, more and more automotive manufacturers seek to outsource their logistics activities to third-party logistics service providers to optimize supply chain management. Milk run system is a typical example of 3PL mode in automotive industry, which can help firms minimize costs and improve logistics function simultaneously. Given the increasing importance of 3PL, many literatures are concerned about the usage of 3PL; however, few of them discussed 3PL form the perspective of China. Besides, in terms of Milk run system, seldom articles focus on this innovative logistics mode, especially in Chinese automotive industry. Therefore, in this thesis work, authors discuss 3PL from the perspective of Chinese automotive industry, especially focus on the typical 3PL mode—Milk run system, set SGM as case company, aiming at find out the factors that facilitate Chinese automotive manufacturers convert self-management mode to 3PL mode, and then discuss the benefits of professional 3PL services; in addition, authors emphasize on Milk run system and its unique benefits. The research objectives are solved by combining literature review and empirical findings. Relevant literatures are downloaded from Internet and Library’s database. Empirical findings are gathered by interviews and questionnaires. Through comparing literature review with findings, both external and internal factors that facilitate automotive manufacturers change logistics mode are summarized. Besides, some professional 3PL services are identified by literature review and validated by questionnaires. According to different categories of 3PL services, their benefits are discussed from two aspects: supply chain integration and core competence improvement. In addition, the benefits of Milk run system are represented by literature review and then through comparing with empirical findings, some unique benefits are summarized. In this thesis work, the main theoretical contribution is the knowledge of Milk run system, which including its features, implementation processes, and its benefits.
|
176 |
Camera System DesignRisberg, Robert January 2003 (has links)
Devices have become increasingly more interconnected to their surroundings over the last few years. The introduction of Bluetooth is likely to further accelerate this trend. With Bluetooth's bandwidth and expected low price, many devices will likely be fitted with Bluetooth chips and thus enable more devices to exchange data. This master thesis aims at connecting a Personal Digital Assistant to an ARM Thumb microcontroller over Bluetooth. To the ARM Thumb shall an image capturing device be interfaced and the captured images shall be sent over Bluetooth to the Personal Digital Assistant which shall display them.
|
177 |
The impacts of outdoor air conditions and non-uniform exchanger channels on a run around membrane energy exchangerHemingson, Howard B 25 February 2011 (has links)
This thesis contains the numerically investigations of the performance of a run-around membrane energy exchanger (RAMEE) at different outdoor air conditions and the effects of non-uniform exchanger channels. The RAMEE is a new type of building ventilation air energy recovery system that allows heat and moisture to be transferred between isolated supply and exhaust air streams. Two liquid-to-air membrane energy exchangers (LAMEEs) are placed in the supply and exhaust air ducts and transfer heat and moisture between air and a circulating liquid desiccant that couples the two LAMEEs together. The ability of the system to transfer heat and moisture between isolated supply and exhaust ducts makes it appropriate for numerous HVAC applications (e.g., hospitals and building energy retrofits). <p>
The performance of the RAMEE at different outdoor air conditions is shown to be highly variable due to the coupling of the heat and moisture transfer by the desiccant. This coupling allows the humidity ratio between the indoor and outdoor air to influence the heat transfer and the moisture transfer is influenced by the difference between the indoor and outdoor air temperatures. The coupling produces some complex RAMEE performance characteristics at some outdoor air conditions where the effectiveness values (i.e., sensible, latent, and total) were shown to be less than 0% or greater than 100%. Effectiveness and operating correlations are developed to describe these complex behaviours because existing correlations do not account for the coupling effects. The correlations can serve as design and operation tools for the RAMEE which do not require the use of an iterative computational numerical model.<p>
Non-uniform exchanger channels are present in the RAMEE because of pressure differences between the air and solution channels which deform the membrane into the air channel. The non-uniform channels are analytically shown to create maldistributed fluid flows and variable heat and mass transfer coefficients. The combined effects of these two changes lead to a reduction in the RAMEE effectiveness, which increases as the size of the membrane deformation increases. The reduction in total effectiveness for an exchanger where the membrane has a peak deflection of 10% of the nominal air channel thickness operating at a NTU of 12 was shown to be 12.5%. These results of non-uniform exchanger channels agree with previously conducted experimental results.
|
178 |
Factors affecting the variance, the bias and the MSE of time averages in Markovian event systemsSethi, Sanjeev 13 June 2007 (has links)
In simulation, time averages are important for estimating equilibrium parameters. In particular, we would like to have the variance, bias and mean-square error for time averages. First, we will discuss various factors and their effect on the bias, the variance and the mean-square error. We will use the Markovian Event System to model various systems, including M/M/1 queues, M/E_k/1 queues, M/M/c queues, sequential queues, inventory systems and queueing networks. We use a numerical method for the computation of the variance, the bias and the mean-square error of the time average. The effectiveness of the method is tested by experimenting with models of various stochastic systems. The contribution of this thesis is to use numerical and graphical interpretations to study the general characteristics of the measures. The important characteristics included in our study are decomposability and periodicity.
|
179 |
Modeling the transient behavior of a run-around heat and moisture exchanger systemSeyed Ahmadi, Mehran 25 November 2008 (has links)
In this thesis, a numerical model for coupled heat and moisture transfer in a run around membrane energy exchanger (RAMEE) with a liquid desiccant as a coupling fluid is developed. The numerical model is two dimensional, transient and is formulated using the finite difference method with an implicit time discretization. The model for the case of only heat transfer for a single heat exchanger is compared to an available analytical solution and good agreement is obtained. It is shown that the discrepancy between the numerical and theoretical dimensionless bulk outlet temperature of the fluids is less than 4% during the transient period. The model is also validated for the case of simultaneous heat and moisture transfer using experimental data measured during the laboratory testing of a RAMEE system. The results for both sensible and latent effectiveness showed satisfactory agreement at different operating conditions. However, there are some discrepancies between the simulation and the experimental data during the transient times. It is proposed that these discrepancies may be due to experimental flow distribution problems within the exchanger. The maximum average absolute differences between the measured and simulated transient effectivenesses were 7.5% and 10.3% for summer and winter operating conditions, respectively.<p>
The transient response of the RAMEE system for step changes in the inlet supply air temperature and humidity ratio is presented using the numerical model. In addition, the system quasi steady state operating conditions are predicted as the system approaches its steady state operating condition. The effect of various dimensionless parameters on the transient response is predicted separately. These included: the number of heat transfer units, thermal capacity ratio, heat loss/gain ratio, storage volume ratio and the normalized initial salt solution concentration. It is shown that the initial salt solution concentration and the storage volume of the salt solution have significant impacts on the transient response of the system and the heat loss/gain rates from/to the circulated fluid flow can change the system quasi steady effectiveness substantially. The detailed study of the transient performance of the RAMEE is useful to determine the transient response time of the system under different practical situations.
|
180 |
Modeling a run-around heat and moisture exchanger using two counter/cross flow exchangersVali, Alireza 29 June 2009 (has links)
In this study, a numerical model is developed for determining coupled heat and moisture transfer in a run-around membrane energy exchanger (RAMEE) using two counter/cross flow exchangers and with a salt solution of MgCl2 as the coupling fluid. The counter/cross flow exchanger is a counter-flow exchanger with cross-flow inlet and outlet headers. The model is two-dimensional, steady-state and based on the physical principles of conservation of momentum, energy, and mass. The finite difference method is used in this model to discretize the governing equations.<p>
The heat transfer model is validated with effectiveness correlations in the literature. It is shown that the difference between the numerical model and correlations is less than ¡À2% and ¡À2.5% for heat exchangers and run around heat exchangers (RAHE), respectively. The simultaneous heat and moisture transfer model is validated with data from another model and experiments. The inter-model comparison shows a difference of less than 1%. The experimental validation shows an average discrepancy of 1% to 17% between the experimental and numerical data for overall total effectiveness. At lower NTUs the numerical and experimental results show better agreement (e.g. within 1-4% at NTU=4).<p>
The model for RAHE is used to develop new effectiveness correlations for the geometrically more complex counter/cross flow heat exchangers and RAHE systems. The correlations are developed to predict the response of the exchangers and overall system to the change of different design characteristics as it is determined by the model. Discrepancies between the simulated and correlated results are within ¡À2% for both the heat exchangers and the RAHE systems.<p>
It is revealed by the model that the overall effectiveness of the counter/cross flow RAMEE depends on the entrance ratio (the ratio of the length of the inlet and outlet headers to the length of the exchanger, xi/x0), aspect ratio (the ratio of the height to the length of the exchanger, y0/x0), number of heat transfer units (NTU), heat capacity rate ratio (Cr*), number of mass transfer units (NTUm), and the mass flow rate ratio of pure salt in desiccant solution to dry air (m*). Beside these dimensionless parameters, the performance of the RAMEE system is affected by the liquid-air flow configuration and the operating inlet temperature and humidity.<p>
This study concludes that the maximum effectiveness of the RAMEE system with two counter/cross flow exchangers occurs when NTU and NTUm are large (e.g. greater than 10). At any NTU, the overall effectiveness of the RAMEE system increases with Cr* until it reaches a maximum value when Cr*= . Increasing Cr* above causes the overall effectiveness to decrease slightly. Therefore, to achieve the maximum overall effectiveness of the system, Cr* must be close to . is a function of NTU and operating conditions e.g., with NTU=10, and under AHRI summer and winter operating conditions, respectively. The exchangers in the RAMEE system are needed to have a small aspect ratio (e.g. y0/x0<0.2) and small entrance ratio (e.g. xi/x0<0.1) to get the maximum overall effectiveness of a RAMEE system using two counter/cross flow exchangers. Such a RAMEE system has a total effectiveness 6% higher and 1.5% lower compared to the same cross-flow and counter-flow RAMEE, respectively (at NTU=10, Cr*¡Ö3, y0/x0=0.2 and xi/x0=0.1).
|
Page generated in 0.042 seconds