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

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

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.

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

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

Dose response severity functions for acoustic disturbance in cetaceans using recurrent event survival analysis

This work was financially supported by the U. S. Office of Naval Research grant N00014‐12‐1‐0204, under the project “Multi‐study Ocean acoustics Human effects Analysis” (MOCHA). . L. Tyack received funding from the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland) and their support is gratefully acknowledged. MASTS is funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions. The case study data were provided by the 3S project, which was funded by the U.S. Office of Naval Research, the Norwegian Ministry of Defense, the Netherlands Ministry of Defense, and WWF Norway.Behavioral response studies (BRSs) aim to enhance our understanding of the behavior changes made by animals in response to specific exposure levels of different stimuli, often presented in an increasing dosage. Here, we focus on BRSs that aim to understand behavioral responses of free-ranging whales and dolphins to manmade acoustic signals (although the methods are applicable more generally). One desired outcome of these studies is dose-response functions relevant to different species, signals and contexts. We adapted and applied recurrent event survival analysis (Cox proportional hazard models) to data from the 3S BRS project, where multiple behavioral responses of different severities had been observed per experimental exposure and per individual based upon expert scoring. We included species, signal type, exposure number and behavioral state prior to exposure as potential covariates. The best model included all main effect terms, with the exception of exposure number, as well as two interaction terms. The interactions between signal and behavioral state, and between species and behavioral state highlighted that the sensitivity of animals to different signal types (a 6–7 kHz upsweep sonar signal [MFAS] or a 1–2 kHz upsweep sonar signal [LFAS]) depended on their behavioral state (feeding or nonfeeding), and this differed across species. Of the three species included in this analysis (sperm whale [Physeter macrocephalus], killer whale [Orcinus orca] and long-finned pilot whale [Globicephala melas]), killer whales were consistently the most likely to exhibit behavioral responses to naval sonar exposure. We conclude that recurrent event survival analysis provides an effective framework for fitting dose-response severity functions to data from behavioral response studies. It can provide outputs that can help government and industry to evaluate the potential impacts of anthropogenic sound production in the ocean.Publisher PDFPeer reviewe

Assessing the quality of health technology registers for national guidance development.

Background: The National Institute of Health and Care Excellence makes use of registers to collect data for technologies that require more evidence to inform future decision-making. This is particularly so for the Interventional Procedures Programme, which since 2003 has produced guidance for procedures that are typically not well established, meaning that named registers are often recommended for future data collection. Methods: We constructed a questionnaire based on quality standards for recommended registers defined by the Interventional Procedures Programme. All guidance from 2003 to 2016 were reviewed to identify recommended registers and compile a list of corresponding registries. We made a maximum of four attempts to contact each registry. Each register was scored on seven quality standards: accessibility, responsiveness, data publication, data coverage, data validity, independent oversight and data protection, with a maximum of 14 points. Results: We obtained responses from 17 out of 24 eligible registries, a response rate of 70.8%. The mean total score was 8.5 (standard deviation 2.9, range 4-14). Overall, the quality of recommended registers was disappointing, with a split between large registries that scored highly across all standards and smaller registries that scored poorly. Conclusions: This the first study to our knowledge to assess the quality of registers recommended by health technology assessment agencies. Only a limited number of registers were mature enough to deliver evidence of sufficiently high quality to inform funding decisions. A standardised quality assessment tool is needed to evaluate registers before their recommendation for observational data gathering by decision-making bodies