The Dynamics of Optimal Risk Sharing

We study a dynamic-contracting problem involving risk sharing between two parties – the Proposer and the Responder – who invest in a risky asset until an exogenous but random termination time. In any time period they must invest all their wealth in the risky asset, but they can share the underlying investment and termination risk. When the project ends they consume their final accumulated wealth. The Proposer and the Responder have constant relative risk aversion R and r respectively, with R > r > 0. We show that the optimal contract has three components: a non-contingent flow payment, a share in investment risk and a termination payment. We derive approximations for the optimal share in investment risk and the optimal termination payment, and we use numerical simulations to show that these approximations offer a close fit to the exact rules. The approximations take the form of a myopic benchmark plus a dynamic correction. In the case of the approximation for the optimal share in investment risk, the myopic benchmark is simply the classical formula for optimal risk sharing. This benchmark is endogenous because it depends on the wealths of the two parties. The dynamic correction is driven by counterparty risk. If both parties are fairly risk tolerant, in the sense that 2 > R > r, then the Proposer takes on more risk than she would under the myopic benchmark. If both parties are fairly risk averse, in the sense that R > r > 2, then the Proposer takes on less risk than she would under the myopic benchmark. In the mixed case, in which R > 2 > r, the Proposer takes on more risk when the Responder’s share in total wealth is low and less risk when the Responder’s share in total wealth is high. In the case of the approximation for the optimal termination payment, the myopic benchmark is zero. The dynamic correction tells us, among other things, that: (i) if the asset has a high return then, following termination, the Responder compensates the Proposer for the loss of a valuable investment opportunity; and (ii) if the asset has a low return then, prior to termination, the Responder compensates the Proposer for the low returns obtained. Finally, we exploit our representation of the optimal contract to derive simple and easily interpretable sufficient conditions for the existence of an optimal contract.

Space station attitude disturbance arising from internal motions

A source of space station attitude disturbances is identified. The attitude disturbance is driven by internal space station motions and is a direct result of conservation of angular momentum. Three examples are used to illustrate the effect: a planar three link system, a rigid carrier body with two moveable masses, and a nonplanar five link system. Simulation results are given to show the magnitude of the attitude change in each example. Factors which accentuate or attenuate this disturbance effect are discussed

Greedy low-rank algorithm for spatial connectome regression

Recovering brain connectivity from tract tracing data is an important computational problem in the neurosciences. Mesoscopic connectome reconstruction was previously formulated as a structured matrix regression problem (Harris et al., 2016), but existing techniques do not scale to the whole-brain setting. The corresponding matrix equation is challenging to solve due to large scale, ill-conditioning, and a general form that lacks a convergent splitting. We propose a greedy low-rank algorithm for connectome reconstruction problem in very high dimensions. The algorithm approximates the solution by a sequence of rank-one updates which exploit the sparse and positive definite problem structure. This algorithm was described previously (Kressner and Sirkovi\'c, 2015) but never implemented for this connectome problem, leading to a number of challenges. We have had to design judicious stopping criteria and employ efficient solvers for the three main sub-problems of the algorithm, including an efficient GPU implementation that alleviates the main bottleneck for large datasets. The performance of the method is evaluated on three examples: an artificial "toy" dataset and two whole-cortex instances using data from the Allen Mouse Brain Connectivity Atlas. We find that the method is significantly faster than previous methods and that moderate ranks offer good approximation. This speedup allows for the estimation of increasingly large-scale connectomes across taxa as these data become available from tracing experiments. The data and code are available online

To what extent has climate change impacted the Total Factor Productivity of the Australian beef industry by state and as a country?

The societal and climatic pressures towards agriculture and specifically the beef industry is increasingly prevalent in recent years. This paper has identified and evaluated the impact of climate on the TFP of the beef sector by state and as a country, which was found to be negative on balance. Additionally, it was found that Victoria was the most susceptible to changes in climate on average, complimenting previous literature that the southern regions of Australia (NSW, VIC, SA, TAS) are more susceptible to changes in climate compared to northern regions on average. Moreover, this paper addressed the current and prospective initiatives and management practices to mitigate the impact of adverse climate aberations, which found that feed additives, the breed of cattle, government subsidised insurance markets and education will assist the productivity of the beef sector in Australia and develop the resilience of farmers during extreme climate aberations

Causal Factors of Australian Beef Exports

This study aims to understand how the macroeconomic and microeconomic indicators influence the export market of beef in Australia as well as the inclusion of a bivariate (0,1) dummy variable, accounting for extreme climate aberrations such as the ‘Millennium Drought’ and the 2017-current drought. Additionally, this study addressed whether there is a delayed effect of the independent variables on Australian beef exports and draw upon neoclassical economic growth theory to assess if this economic paradigm holds in the real world. The paper identified and evaluated the casual factors of Australian beef exports and found there to be a two-quarter lag in bank loans to agriculture and a one-quarter lag in RBA interest rate before their effect was statistically significant. The results explore the various implications that depend on the perspective of the stakeholder, whether that be the farmer or the government

The Trans Pacific Partnership Agreement negotiations and the health of Australians

The Trans Pacific Partnership Agreement has the potential to negatively impact the health of Australians by raising the cost of medicine and limiting the government\u27s ability to regulate tobacco and alcohol, argues this policy brief based on publicly available and recently leaked negotiating documents. Executive summary The purpose of this policy brief is to inform the debate from a health perspective in the final stages of the negotiations on the Trans Pacific Partnership Agreement (TPPA), particularly during meetings of chief negotiators and ministers in February 2014. This policy brief outlines the evidence about the potential health effects on the Australian community of actions related to the TPPA, based on publicly available and recently leaked negotiating documents. The purpose of the TPPA is to enhance each of the countries’ economic development and that this may lead to improved social and health development. However, although there may be positive impacts on the health and wellbeing of Australians resulting from economic growth, there are also many ways in which the TPPA has the potential to have negative impacts on the health of Australians. This policy brief examines the potential impact of provisions proposed for the TPPA on the health of Australians, focusing on two specific issues: the cost of medicines, and the ability of government to take major steps to improve the health of Australians by regulating the areas of tobacco and alcohol policy. In each of these areas we trace some of the pathways through which provisions that have been proposed for the TPPA may impact on the health of the Australian population, and the health of specific groups within the population. We highlight the ways in which some of the expected economic gains from the TPPA may be undermined by health and economic costs. Concerning the cost of medicine we focus on how proposed provisions in the TPPA could impact the affordability of medicines through several different routes: by delaying the availability of cheaper generic medicines, by altering the operation of the Pharmaceutical Benefits Scheme (PBS) making it more difficult to keep costs down, and by enabling pharmaceutical companies to sue the government over its pharmaceutical policies. These changes would increase the cost of the PBS for the government and taxpayers. Strategies to compensate for an increase in medication costs include increased cost-sharing, with patients assuming higher co-payments, or funding reallocation from other parts of the healthcare system. Provisions in the TPPA may impact the ability of Government to enforce existing policies and implement new policies that support public health. Australia is internationally recognised for the success of comprehensive strategies to reduce tobacco smoking. And more recently, there are multiple initiatives being proposed to achieve similar success to reduce harmful use of alcohol. We outline several of the many provisions in the TPPA that could affect tobacco and alcohol policies in Australia. Concerning tobacco these include an investor-state dispute settlement mechanism clause in the TPPA would provide more opportunities for tobacco companies to sue the Australian government over strong tobacco control measures. Rules about ‘indirect expropriation’ (i.e. depriving an investor of property, which, if broadly defined, can include intellectual property such as trademarks) and ‘fair and equitable treatment’ provide additional grounds for corporations to argue that their assets are being unfairly affected by government policies and laws. Provisions in the TPPA may impact the Government’s ability to implement effective alcohol control policies such as restrictions on liquor licences, bans or limits on alcohol advertising, and alcohol health warning labels. Concerning alcohol these include provisions in the Technical Barriers to Trade (TBT) Chapter of the TPPA which could limit possibilities for introducing innovative alcohol policies, such as requiring health warning labels. Provisions in the wine and spirits annex to the TBT Chapter may limit the options available to create a fully effective alcohol warnings scheme for wine and spirits. If Australia agrees to an investor-state dispute settlement (ISDS) mechanism applying to Australia, the alcohol industry will have access to a new legal channel to sue the Australian Government over alcohol policy decisions that adversely impact their investments. We conclude that while there is some potential for the TPPA to contribute to economic development, there is also significant risk that the economic gains which the TPPA may represent, as well as the health of the Australian community, will be threatened if certain proposed provisions are adopted for the TPPA. These include increased direct costs in terms of providing health care and increased use of hospitals, higher costs of obtaining pharmaceuticals, indirect costs associated with lost productivity across society, continuing or exacerbating inequalities in society, and worsening the health of Australia’s already vulnerable communities. Authored by: Katie Hirono, Centre for Health Equity Training, Research and Evaluation, University of New South Wales Deborah Gleeson, School of Public Health and Biosciences, La Trobe University Fiona Haigh, Centre for Health Equity Training, Research and Evaluation, University of New South Wales Patrick Harris, Centre for Health Equity Training, Research and Evaluation, University of New South Wale

Comparison of life history parameters for landed and discarded fish captured off the southeastern United States

Commercial fisheries that are managed with minimum size limits protect small fish of all ages and may affect size-selective mortality by the differential removal of fast growing fish. This differential removal may decrease the average size at age, maturation, or sexual transition of the exploited population. When fishery-independent data are not available, a comparison of life history parameters of landed with those of discarded fish (by regulation) will indicate if differential mortality is occurring with the capture of young but large fish (fast growing phenotypes). Indications of this differential size-selective mortality would include the following: the discarded portion of the target fish would have similar age ranges but smaller sizes at age, maturation, and sexual transition as that of landed fish. We examined three species with minimum size limits but different exploitation histories. The known heavily exploited species (Rhomboplites aurorubens [vermilion snapper] and Pagrus pagrus [red porgy]) show signs of this differential mortality. Their landed catch includes many young, large fish, whereas discarded fish had a similar age range and mean ages but smaller sizes at age than the landed fish. The unknown exploited species, Mycteroperca phenax (scamp), showed no signs of differential mortality due to size-selective fishing. Landed catch consisted of old, large fish and discarded scamp had little overlap in age ranges, had significantly different mean ages, and only small differences in size at age when compared to comparable data for landed fish

Drilling Optimisation on the Norwegian Continental Shelf: Opportunities in Well Design Practice

Master's Thesis in Petroleum EngineeringThe purpose of this thesis was to attempt to provide evidence that Norway’s drilling fraternity is long overdue for a re-think in the way it drills wells. In so doing, the author has chosen to focus on slim well drilling as a means of reducing drill costs. It was postulated that slim well drilling could lead to much lower drilling investment costs. This body of work therefore focuses on the regulatory, economic and technical implications of slim hole drilling in Norway. The study examined the historical trends of drilling optimisation, particularly in light of the recent downturn. It was discovered that drilling investment costs in Norway have increased three-fold since the year 2000 with drilling and wells contributing 50% of that overall investment (>NOK100B per year). Whilst there has indeed been some improvement in efficiency since 2014, there is still a major issue with hidden NPT and overall rig crew efficiency. There are, however, some exciting developments in play for slimming down explorations wells in Norway, with the possibility of even drilling with a single casing string being considered. To attempt to indicate that slim wells are indeed possible, six hypothetical exploration wells were examined. Two in the North Sea, another two in the Norwegian Sea and the remainder in the Barents Sea. These regions were chosen to give the broadest possible outlook for the opportunities and challenges at play for the Norwegian sector. For each region, one conventional well design and one slender well proposal was analysed and despite an absence of some data, realistic assumptions were made based on publically available data from Norwegian operators. From a technical standpoint, our analysis concluded the following: • For each conventional well presented, it was technically possible to remove one or two casing strings, with no lost production and well integrity remaining intact; • The limiting technical factor in slim well design is kick tolerance. All slim hole options required changes to casing set depth and hole size due to kick tolerance; • Due to recent advances in downhole technology, the use of tools such as alternate-flow through casing shoes mean ECD’s are not the problem they would otherwise be. By under-reaming certain hole sections and using managed pressure drilling, ECD’s can be further reduced, as can annular pressures during cementing; In assessing the technical merits of slim well drilling, an economic model was developed for each of the six drill proposals. A number of realistic assumptions were made based on ballpark materials pricing and some limited drill cost data from an undisclosed operator. Our economic analysis concluded the following: • Simply slimming down a well, all casing depths remaining equal may not necessarily be economically beneficial. This will depend entirely on operating time; • Material cost savings, while significant, only play a minute role in reducing wellbore costs. These savings will fluctuate depending on the operating company’s competitive market advantage in securing lower per-unit material costs; • The primary cost driver of economically successful slim well drilling is rig crew performance; The study rounds-up with an expose of the current opportunities and challenges facing industry today. Whilst it is easy to show evidence of the techno-economic merits of slim hole drilling, it was thought prudent to examine the current industry appetite for these sorts of wells, in light of the challenges which need to be overcome before commercialisation of slim hole drilling can occur. The biggest roadblocks currently hindering the commercial success of slim hole drilling are the preventive drilling rig certification costs for new rigs in Norway and the current state of the local OCTG market. A number of recommendations to industry were presented: • Standardisation of drilling rig certification processes and regulations between Denmark, Norway and the UK (North Sea sector); • Standardisation of manufacturing, operating and documenting practises across industry; • The implementation of rig crew performance incentive schemes, which are particularly important given that the economic merits of slim wells hinge on a high performing crew; • Implementing risk sharing models to ensure a more stable flow of income/expense, as well as reviewing the ways in which rig costs are set; • “Going digital”. Implementing digital well planning to drive down costs. In closing, this thesis concludes that slim wells are a lucrative option for Norwegian operating companies, in that they are technically sound for the Norwegian Continental Shelf and economically viable given a prevalence of the conditions outlined above.Pro Well Plan A

A Design for a Proposed Skill Proficiency Test in Tumbling and Apparatus for Male Physical Education Majors at the University of North Dakota

The purpose of this study was to design an instrument that would measure the tumbling and apparatus skill proficiency of male physical education majors of the University of North Dakota. Two groups were used in the study. An experimental group of fifteen subjects, which was taking the required tumbling and apparatus course five times weekly; and a control group of ten subjects that had taken the same class the semester before, were utilized in this study. The two groups were given the initial test for purposes of determining item validity. The experimental group was also given a retest to determine test item reliability. Two statistical comparisons were made: (1) a within group comparison between the initial test and retest means given to the experimental group, and (2) a comparison between the means on the initial test of both groups in the areas tested. The null hypothesis was assumed in analyzing the significance of the difference between the means, of the within group comparison for reliability, at the .05 level. The .10 level of significance was used to determine item validity in the between group comparison. The results of the within group comparison showed a significant difference in eight of the twenty-two items tested, and therefore these items were rejected. The between group comparison indicated six items to be significant. It was concluded that the six items found statistically significant in both between group comparisons were reliable and valid test items for measuring tumbling and apparatus skill proficiency, fore, these test items made up the final test battery

Negotiating healthy trade in Australia: health impact assessment of the proposed Trans-Pacific Partnership Agreement

Drawing on leaked texts of potential provisions of the proposed Trans-Pacific Partnership Agreement, this health impact assessment found the potential for negative impacts in the cost of medicines, tobacco control policies, alcohol control policies, and food labeling. Overview The Centre for Health Equity Training Research and Evaluation (CHETRE) has been working with a group of Australian academics and non-government organisations interested in the health of the Australian population to carry out a health impact assessment (HIA) on the Trans-Pacific Partnership Agreement (TPP) negotiations. In the absence of official publicly available drafts of the trade agreement, the health impact assessment drew on leaked texts of potential provisions and formulated policy scenarios based on high priority health policies that could be affected by the TPP. The HIA found the potential for negative impacts in each of the four areas under investigation: the cost of medicines; tobacco control policies; alcohol control policies; and food labeling. In each of these areas, the HIA report traces the relevant proposed provisions through to their likely effects on the policy scenarios onto the likely impact on the health of Australians, focusing particularly on vulnerable groups in the Australian community. The report makes a number of recommendations to DFAT regarding the TPP provisions and to the Australian Government regarding the TPP negotiating process