3,599 research outputs found
The nature of cometary materials
Because cometary surfaces are likely to be far colder and of a different composition than planetary surfaces, there are some new considerations that must be examined in regards to placing instrumented packages or sample return devices on their surfaces. The qualitative analysis of the problem of attaching hardware to a comet and not being ejected back into space can be divided into two parts. The first problem is to pierce the mantle and obtain access to the icy core. Drilling through the mantle requires that the drilling forces be reacted. Reacting such forces probably requires attachment to the icy core below. Therefore, some kinetic impact piercing device is likely to be required as the first act of attachment. The second problem for a piercing device to overcome is the force produced by the impact kinetic energy that tries to eject the piercing device back into space. The mantle and icy core can absorb some of the impact kinetic energy in the form of fracture formation and friction energy. The energy that is not absorbed in these two ways is stored by the core as elastic deformation of the mantle and icy core. It is concluded that because the cometary materials are almost certainly brittle and the icy core is likely to be self lubricating, the elastic rebound and gas pressure expulsion forces must be counteracted by forces greater than those that may be provided by a piercing device or its capture devices (barbs)
CDS as Insurance: Leaky Lifeboats in Stormy Seas
In this paper we update the traditional insurance economics framework to incorporate key features of the credit default swap (CDS) market. First, we allow for insurer insolvency, with asymmetric information as to its probability. We find that stable insurers become less stable because they are forced to compete on price. When insurer type is known, increased competition among insurers can create instability for the same reason. Second, we allow the insured party to have heterogeneous motivations for purchasing CDS. For example, some may own the underlying asset and purchase CDS for risk management, while others buy these contracts purely for speculation. We show that speculators will choose to contract with less stable insurers, resulting in higher counterparty risk in this market relative to that of traditional insurance; however, a regulatory policy that disallows speculative trading can, perversely, cause market counterparty risk to increase. Third, we relax the standard assumption of contract exclusivity, which does not apply to the CDS market, by allowing the insured to purchase contracts from many insurers. In contrast to the traditional insurance model, we show that separation of risk type among insured parties can be achieved through insurer choice. We use our model to shed light on the debate over Central Counterparties (CCP). We show that requiring CDS contracts to be negotiated through CCPs can push stable insurers out of the market, mitigating the benefi t of risk pooling.credit default swaps; insurance; counterparty risk; banking; regulation
How to make a comet
The primary mandate of NASA is the study of the nature and origin of the solar system. The study of the comets provide information about conditions and processes at the beginning of the solar system. Short period comets and their relatives, the near Earth asteroids may prove to be second only to the sun in importance to the long term survival of civilization for two reasons. The short period comets and the near Earth asteroids are a possible candidate for the cause of mass extinctions of life on Earth; and they may provide the material means for the expansion of civilization into the solar system and beyond. The comets and near Earth asteroids almost certainly represent the most primitive material of the solar system, still tantalizingly unavailable until spacecraft bring first-hand information. In the meantime comets must be studied by remote means. Laboratory investigations using synthetic cometary materials may add to the knowledge of these interesting objects. Experimentation on comet synthesis is briefly discussed
PUBH 7890 - Independent Study
Foundational economics and specific health economics theory, trends, market issues and applications are presented to include health insurance and payment theory, processes and applications. Comparison between rational and irrational theory is explored. Evolutions of health policy, considering past current and future major legislation and executive directives, are explored within the political process
PhD
dissertationFor a peptide vaccine to be effective in generating an antibody response, it generally must incorporate both B cell epitopes, against which the antibody response is to be directed, and T cell epitopes, which are responsible for stimulating helper T cells. The first part of this work is concerned with the question, How well can a T cell epitope replace the carrier protein from which it is derived?" To answer this question two studies were done: an initial, direct comparison between a protein (the Fab' fragment of murine monoclonal anti-fluorescein antibody 9-40) coupled to hen egg lysozyme (HEL) and the same protein coupled to the immunodominant T cell epitope from HEL for BIO.A (H-2a) mice, along with negative controls, and a second, dose response study with fluorescein (FL) as the B cell epitope attached to a multiple antigenic peptide (MAP) version of this T cell epitope, along with positive and negative controls (HEL and a MAP in which the epitope sequence was replaced by glycine residues, respectively). This study showed a half-sigmoidal curve for the FL-(T epitope) immunogen, no response to the negative control except at the highest dose used, and a fairly constant and high response for both the experimental MAP and the fluoresceinated HEL. The initial study described above gave a very specific anti-idiotype response for the (9-40)Fab'-HEL construct. Another, follow-up study comparing a peptide mimic based on an important idiotope, the third complementarity determining region of the heavy chain (the CDR-H3 loop), to the intact idiotype was also conducted. In this study the peptide mimic of the CDR-H3 loop was the B cell epitope; it was also coupled to HEL. The question being addressed was, "How well can an idiotope peptide mimic replace its parent idiotype?" B10.A mice were immunized with (B epitope)-HEL, (9-40)Fab'-HEL, (B epitope) + HEL mixed together, or just the B epitope. The essential issue was crossreactivity, and this was observed to increase with succeeding immunizations. Molecular dynamics simulations with generalized Born implicit solvation or particle mesh Ewald electrostatics were also used to provide insight into the structural basis of idiotopic phenomena
HSPM 7137 - Healthcare Finance and Payment Systems
This course examines the structure and functioning of the finance reimbursement components of the health care delivery system. Healthcare organizations including hospitals, long-term care, ambulatory care, managed care, private and public insurance, public health, integrated delivery systems, and other health care providers will be discussed within the context of the financial environment that includes financial management, managerial accounting and revenue and reimbursement cycle management. The course also examines key financial tools and analyses for financially related decision making within the principles of strategic management applied to healthcare organizations amid a dynamic/changing environment
The relationship of vitamin K to cecal coccidiosis of chickens
The objectives of the experiments reported in this thesis were to determine (1) the effects of vitamin K on blood clotting time, weight gain, and mortality from cecal coccidiosis in experimentally inoculated chickens, (2) the effects of various levels of vitamin K on blood clotting time, mortality, and weight gain of chicks inoculated with varying numbers of sporulated Eimeria tenella oocysts, and (3) the relative efficacies of Nicarbazin and four potential sources of vitamin K in the prevention of morbidity and mortality in birds fed diets low in vitamin K and experimentally infected with cecal coccidiosis
PhD
dissertationFor a peptide vaccine to be effective in generating an antibody response, it generally must incorporate both B cell epitopes, against which the antibody response is to be directed, and T cell epitopes, which are responsible for stimulating helper T cells. The first part of this work is concerned with the question, How well can a T cell epitope replace the carrier protein from which it is derived?" To answer this question two studies were done: an initial, direct comparison between a protein (the Fab' fragment of murine monoclonal anti-fluorescein antibody 9-40) coupled to hen egg lysozyme (HEL) and the same protein coupled to the immunodominant T cell epitope from HEL for BIO.A (H-2a) mice, along with negative controls, and a second, dose response study with fluorescein (FL) as the B cell epitope attached to a multiple antigenic peptide (MAP) version of this T cell epitope, along with positive and negative controls (HEL and a MAP in which the epitope sequence was replaced by glycine residues, respectively). This study showed a half-sigmoidal curve for the FL-(T epitope) immunogen, no response to the negative control except at the highest dose used, and a fairly constant and high response for both the experimental MAP and the fluoresceinated HEL. The initial study described above gave a very specific anti-idiotype response for the (9-40)Fab'-HEL construct. Another, follow-up study comparing a peptide mimic based on an important idiotope, the third complementarity determining region of the heavy chain (the CDR-H3 loop), to the intact idiotype was also conducted. In this study the peptide mimic of the CDR-H3 loop was the B cell epitope; it was also coupled to HEL. The question being addressed was, "How well can an idiotope peptide mimic replace its parent idiotype?" B10.A mice were immunized with (B epitope)-HEL, (9-40)Fab'-HEL, (B epitope) + HEL mixed together, or just the B epitope. The essential issue was crossreactivity, and this was observed to increase with succeeding immunizations. Molecular dynamics simulations with generalized Born implicit solvation or particle mesh Ewald electrostatics were also used to provide insight into the structural basis of idiotopic phenomena
PhD
dissertationFor a peptide vaccine to be effective in generating an antibody response, it generally must incorporate both B cell epitopes, against which the antibody response is to be directed, and T cell epitopes, which are responsible for stimulating helper T cells. The first part of this work is concerned with the question, How well can a T cell epitope replace the carrier protein from which it is derived?" To answer this question two studies were done: an initial, direct comparison between a protein (the Fab' fragment of murine monoclonal anti-fluorescein antibody 9-40) coupled to hen egg lysozyme (HEL) and the same protein coupled to the immunodominant T cell epitope from HEL for BIO.A (H-2a) mice, along with negative controls, and a second, dose response study with fluorescein (FL) as the B cell epitope attached to a multiple antigenic peptide (MAP) version of this T cell epitope, along with positive and negative controls (HEL and a MAP in which the epitope sequence was replaced by glycine residues, respectively). This study showed a half-sigmoidal curve for the FL-(T epitope) immunogen, no response to the negative control except at the highest dose used, and a fairly constant and high response for both the experimental MAP and the fluoresceinated HEL. The initial study described above gave a very specific anti-idiotype response for the (9-40)Fab'-HEL construct. Another, follow-up study comparing a peptide mimic based on an important idiotope, the third complementarity determining region of the heavy chain (the CDR-H3 loop), to the intact idiotype was also conducted. In this study the peptide mimic of the CDR-H3 loop was the B cell epitope; it was also coupled to HEL. The question being addressed was, "How well can an idiotope peptide mimic replace its parent idiotype?" B10.A mice were immunized with (B epitope)-HEL, (9-40)Fab'-HEL, (B epitope) + HEL mixed together, or just the B epitope. The essential issue was crossreactivity, and this was observed to increase with succeeding immunizations. Molecular dynamics simulations with generalized Born implicit solvation or particle mesh Ewald electrostatics were also used to provide insight into the structural basis of idiotopic phenomena
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