199 research outputs found

    A Transactional Model and Platform for Designing and Implementing Reactive Systems

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    A reactive program is one that has ongoing interactions with its environment. Reactive programs include those for embedded systems, operating systems, network clients and servers, databases, and smart phone apps. Reactive programs are already a core part of our computational and physical infrastructure and will continue to proliferate within our society as new form factors, e.g. wireless sensors, and inexpensive (wireless) networking are applied to new problems. Asynchronous concurrency is a fundamental characteristic of reactive systems that makes them difficult to develop. Threads are commonly used for implementing reactive systems, but they may magnify problems associated with asynchronous concurrency, as there is a gap between the semantics of thread-based computation and the semantics of reactive systems: reactive software developed with threads often has subtle timing bugs and tends to be brittle and non-reusable as a holistic understanding of the software becomes necessary to avoid concurrency hazards such as data races, deadlock, and livelock. Based on these problems with the state of the art, we believe a new model for developing and implementing reactive systems is necessary. This dissertation makes four contributions to the state of the art in reactive systems. First, we propose a formal yet practical model for (asynchronous) reactive systems called reactive components. A reactive component is a set of state variables and atomic transitions that can be composed with other reactive components to yield another reactive component. The transitions in a system of reactive components are executed by a scheduler. The reactive component model is based on concepts from temporal logic and models like UNITY and I/O Automata. The major contribution of the reactive component model is a formal method for principled composition, which ensures that 1) the result of composition is always another reactive component, for consistency of reasoning; 2) systems may be decomposed to an arbitrary degree and depth, to foster divide-and-conquer approaches when designing and re-use when implementing; 3)~the behavior of a reactive component can be stated in terms of its interface, which is necessary for abstraction; and 4) properties of reactive components that are derived from transitions protected by encapsulation are preserved through composition and can never be violated, which permits assume-guarantee reasoning. Second, we develop a prototypical programming language for reactive components called rcgo that is based on the syntax and semantics of the Go programming language. The semantics of the rcgo language enforce various aspects of the reactive component model, e.g., the isolation of state between components and safety of concurrency properties, while permitting a number of useful programming techniques, e.g., reference and move semantics for efficient communication among reactive components. For tractability, we assume that each system contains a fixed set of components in a fixed configuration. Third, we provide an interpreter for the rcgo language to test the practicality of the assumptions upon which the reactive component model are founded. The interpreter contains an algorithm that checks for composition hazards like recursively defined transitions and non-deterministic transitions. Transitions are executed using a novel calling convention that can be implemented efficiently on existing architectures. The run-time system also contains two schedulers that use the results of composition analysis to execute non-interfering transitions concurrently. Fourth, we compare the performance of each scheduler in the interpreter to the performance of a custom compiled multi-threaded program, for two reactive systems. For one system, the combination of the implementation and hardware biases it toward an event-based solution, which was confirmed when the reactive component implementation outperformed the custom implementation due to reduced context switching. For the other system, the custom implementation is not prone to excessive context switches and outperformed the reactive component implementations. These results demonstrate that reactive components may be a viable alternative to threads in practice, but that additional work is necessary to generalize this claim

    Snatch trajectory of elite level girevoy (Kettlebell) sport athletes and its implications to strength and conditioning coaching

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    Girevoy sport (GS) has developed only recently in the West, resulting in a paucity of English scientific literature available. The aim was to document kettlebell trajectory of GS athletes performing the kettlebell snatch. Four elite GS athletes (age = 29-47 years, body mass = 68.3-108.1 kg, height 1.72-1.89 m) completed one set of 16 repetitions with a 32.1 kg kettlebell. Trajectory was captured with the VICON motion analysis system (250 Hz) and analysed with VICON Nexus (1.7.1). The kettlebell followed a ‘C’ shape trajectory in the sagittal plane. Mean peak velocity in the upwards phase was 4.03 ± 0.20 m s –1, compared to 3.70 ± 0.30 m s–1 during the downwards phase, and mean radial error across the sagittal and frontal planes was 0.022 ± 0.006 m. Low error in the movement suggests consistent trajectory is important to reduce extraneous movement and improve efficiency. While the kettlebell snatch and swing both require large anterior-posterior motion, the snatch requires the kettlebell to be held stationary overhead. Therefore, a different coaching application is required to that of a barbell snatch

    Health empowerment scripts : simplifying social/green prescriptions

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    Social prescriptions are one term commonly used to describe non-pharmaceutical approaches to healthcare and are gaining popularity in the community, with evidence highlighting psychological benefits of reduced anxiety, depression and improved mood and physiological benefits of reduced risk of cardiovascular disease and reduced hypertension. The relationship between human health benefits and planetary health benefits is also noted. There are, however, numerous barriers, such as duration and frequencies to participate in activities, access, suitability, volition and a range of unpredictable variables (such as inclement weather, shifting interests and relocating home amongst others) impeding a comprehensive approach to their use on a wider scale. From a multidisciplinary perspective, this commentary incorporates a salutogenic and nature-based approach to health, we also provide a range of recommendations that can be undertaken at the patient level to assist in shifting the acknowledged systemic barriers currently occurring. These include using simple language to explain the purpose of health empowerment scripts, ensuing personal commitment to a minimum timeframe, enabling ease of access, co-designing a script program, providing ongoing motivational support and incorporating mindfulness to counter unexpected disruptions. Copyright © 2022 Lawson, Wissing, Henderson-Wilson, Snell, Chambers, McNeil and Nuttman

    Wolf-Livestock Conflict in Montana: Spatial and Temporal Factors Influencing Livestock Loss

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    Successful wolf (Canis lupus) recovery in Montana has brought with it some negative impacts on livestock producers in certain areas and time periods.  We assessed the spatial and temporal patterns of wolf depredations on livestock in Montana at a broad, statewide scale during the past decade (2005–2014).  These analyses highlighted areas of concentrated and consistent wolf-livestock conflicts, such that, for example, 50% of the statewide conflicts occur in 5% of the state.  We then used generalized linear mixed-models to test covariates potentially predictive of both conflict presence (zero vs. non-zero depredation events) and conflict severity (number of events given at least 1), including the assessment of lethal controls and hunter harvest as tools to reduce conflicts.  Using administrative hunting districts (HDs) as the unit of analysis, we found that conflict presence increased for HD-years with wolves present (P<0.001), higher wolf pack densities (P=0.006), higher livestock densities (P<0.001), and intermediate proportionate areas of agricultural land (P<0.001).  HDs with depredations the previous year were more likely to continue having them (P<0.001), though lethal removal of wolves significantly reduced this effect (P=0.038).  Direct effects of wolf hunter harvest were shown to marginally (P=0.152) reduce year-to-year conflicts, but indirect effects of harvest would also be expected given its role in determining wolf numbers, a primary driver of conflicts.  Minimizing livestock losses is a top priority for successful wolf management, and these results shed light on the broad-scale patterns behind chronic problems and the tools used to address them

    The Ninth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-III Baryon Oscillation Spectroscopic Survey

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    The Sloan Digital Sky Survey III (SDSS-III) presents the first spectroscopic data from the Baryon Oscillation Spectroscopic Survey (BOSS). This ninth data release (DR9) of the SDSS project includes 535,995 new galaxy spectra (median z=0.52), 102,100 new quasar spectra (median z=2.32), and 90,897 new stellar spectra, along with the data presented in previous data releases. These spectra were obtained with the new BOSS spectrograph and were taken between 2009 December and 2011 July. In addition, the stellar parameters pipeline, which determines radial velocities, surface temperatures, surface gravities, and metallicities of stars, has been updated and refined with improvements in temperature estimates for stars with T_eff<5000 K and in metallicity estimates for stars with [Fe/H]>-0.5. DR9 includes new stellar parameters for all stars presented in DR8, including stars from SDSS-I and II, as well as those observed as part of the SDSS-III Sloan Extension for Galactic Understanding and Exploration-2 (SEGUE-2). The astrometry error introduced in the DR8 imaging catalogs has been corrected in the DR9 data products. The next data release for SDSS-III will be in Summer 2013, which will present the first data from the Apache Point Observatory Galactic Evolution Experiment (APOGEE) along with another year of data from BOSS, followed by the final SDSS-III data release in December 2014.Comment: 9 figures; 2 tables. Submitted to ApJS. DR9 is available at http://www.sdss3.org/dr

    ISBS 2018 AUCKLAND CONFERENCE SPRINZ-HPSNZ-AUT MILLENNIUM APPLIED PROGRAMME

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    An interactive afternoon of sessions delivered by High Performance Sport New Zealand (HPSNZ) and AUT SPRINZ Biomechanists, Performance Analysts and other biomechanics relevant sport facing practitioners. The 11 sessions are at AUT Millennium (AUTM), which is a satellite site of AUT University and the Auckland training hub for many HPSNZ supported sports such as athletics, sailing, and swimming. These sports and others (cycling, rowing, snow sports etc.) will be represented in the line-up. The applied sessions involve practical demonstrations of aspects of analysis and/or tools used to deliver in the field to directly positively impact athletes performances on the world stage. Following these engaging sessions there will be tasting of New Zealand wine, allowing for further discussion and networking. Sir Graeme Avery will be acknowledged for his contribution to sport science. Mike Stanley is AUT Millennium Chief Executive & NZ Olympic Committee President will explain the partners in the facility. AUT Millennium is a charitable trust established to help New Zealanders live longer and healthier lives, and to enjoy and excel in sport through the provision of world-class facilities, services, research and education. Founded in 2002 as Millennium Institute of Sport and Health (MISH) by Sir Stephen Tindall and Sir Graeme Avery as a premium health and fitness facility for both athletes and the public alike. Partnered with AUT University in 2009, forming AUT Millennium, to expand research and education in the sporting sector. Professor Barry Wilson is an Adjunct Professor with SPRINZ at Auckland University of Technology and will be outlining the research and student opportunities. Martin Dowson is the General Manager Athlete Performance Support at High Performance Sport New Zealand and has overall responsibility for the programme. Simon Briscoe, AUT Millennium Applied Session Coordinator, is the head of the Performance and Technique Analysis discipline within HPSNZ. Simon is coordinating the applied sessions along with technical support from Dr Allan Carman, Research Fellow, AUT SPRINZ. Jodi Cossor and Matt Ingram will provide a demonstration of a multidisciplinary approach driven by biomechanical analysis for Paralympic swimmers. Justin Evans and Sarah-Kate Millar will provide a practical session assessing the athletes rowing stroke to assist the coach on technical changes. This session will demonstrate various rowing traits and how the biomechanist and coach can work together to optimise boat speed. Mike Schofield and Kim HĂ©bert-Losier will provide a session looking at shotput and the evidence based approach to coaching. Dr Craig Harrison and Professor John Cronin will provide examples from the AUTM Athlete Development programme. Kim Simperingham and Jamie Douglas who work with high performance rugby athletes will outline sprinting mechanics in practice. Dr Bruce Hamilton, Fiona Mather, Justin Ralph and Rone Thompson will demonstrate the approach of HPSNZ and Cycling NZ performance health teams in the use of some specific tools for prevention of injury and optimisation of performance. Kelly Sheerin, Denny Wells and Associate Professor Thor Besier will provide examples of using IMU and motion capture methods for running and basketball biomechanics research, education and service. Dr Rodrigo Bini and Associate Professor Andrew Kilding will show how linking of biomechanics and physiology improves injury prevention and performance enhancement. Robert Tang, Andre de Jong and Farhan Tinwala discuss select projects developed by Goldmine, HPSNZ’s in-house engineering team, and how these innovations have enabled unprecedented levels of biomechanics feedback. Cameron Ross and Paul McAlpine demonstrate the technology being used at the Snow Sports NZ training centre in Cadrona to enhance load monitoring of athletes. This application allows greater insight into training performances and biomechanical loads than has been previously possible in the training environment. AUT Millennium tour guides are coordinated by Josh McGeown and include Enora Le Flao, Dustin Oranchuk, Erika Ikeda, Jono Neville, Aaron Uthoff, Andrew Pichardo, Farhan Tinwala, Shelley Diewald, Renata Bastos Gottgtroy, Jessica Yeoman, Casey Watkins, Eric Harbour, Anja Zoellner, Alyssa Joy Spence, Victor Lopez Jr, and Albert Chang

    Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

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    Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy

    A Scalable System for Production of Functional Pancreatic Progenitors from Human Embryonic Stem Cells

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    Development of a human embryonic stem cell (hESC)-based therapy for type 1 diabetes will require the translation of proof-of-principle concepts into a scalable, controlled, and regulated cell manufacturing process. We have previously demonstrated that hESC can be directed to differentiate into pancreatic progenitors that mature into functional glucose-responsive, insulin-secreting cells in vivo. In this study we describe hESC expansion and banking methods and a suspension-based differentiation system, which together underpin an integrated scalable manufacturing process for producing pancreatic progenitors. This system has been optimized for the CyT49 cell line. Accordingly, qualified large-scale single-cell master and working cGMP cell banks of CyT49 have been generated to provide a virtually unlimited starting resource for manufacturing. Upon thaw from these banks, we expanded CyT49 for two weeks in an adherent culture format that achieves 50–100 fold expansion per week. Undifferentiated CyT49 were then aggregated into clusters in dynamic rotational suspension culture, followed by differentiation en masse for two weeks with a four-stage protocol. Numerous scaled differentiation runs generated reproducible and defined population compositions highly enriched for pancreatic cell lineages, as shown by examining mRNA expression at each stage of differentiation and flow cytometry of the final population. Islet-like tissue containing glucose-responsive, insulin-secreting cells was generated upon implantation into mice. By four- to five-months post-engraftment, mature neo-pancreatic tissue was sufficient to protect against streptozotocin (STZ)-induced hyperglycemia. In summary, we have developed a tractable manufacturing process for the generation of functional pancreatic progenitors from hESC on a scale amenable to clinical entry

    Patterns of Polymorphism and Demographic History in Natural Populations of Arabidopsis lyrata

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    Many of the processes affecting genetic diversity act on local populations. However, studies of plant nucleotide diversity have largely ignored local sampling, making it difficult to infer the demographic history of populations and to assess the importance of local adaptation. Arabidopsis lyrata, a self-incompatible, perennial species with a circumpolar distribution, is an excellent model system in which to study the roles of demographic history and local adaptation in patterning genetic variation.We studied nucleotide diversity in six natural populations of Arabidopsis lyrata, using 77 loci sampled from 140 chromosomes. The six populations were highly differentiated, with a median FST of 0.52, and structure analysis revealed no evidence of admixed individuals. Average within-population diversity varied among populations, with the highest diversity found in a German population; this population harbors 3-fold higher levels of silent diversity than worldwide samples of A. thaliana. All A. lyrata populations also yielded positive values of Tajima's D. We estimated a demographic model for these populations, finding evidence of population divergence over the past 19,000 to 47,000 years involving non-equilibrium demographic events that reduced the effective size of most populations. Finally, we used the inferred demographic model to perform an initial test for local adaptation and identified several genes, including the flowering time gene FCA and a disease resistance locus, as candidates for local adaptation events.Our results underscore the importance of population-specific, non-equilibrium demographic processes in patterning diversity within A. lyrata. Moreover, our extensive dataset provides an important resource for future molecular population genetic studies of local adaptation in A. lyrata

    The Seventeenth Data Release of the Sloan Digital Sky Surveys: Complete Release of MaNGA, MaStar and APOGEE-2 Data

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    This paper documents the seventeenth data release (DR17) from the Sloan Digital Sky Surveys; the fifth and final release from the fourth phase (SDSS-IV). DR17 contains the complete release of the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey, which reached its goal of surveying over 10,000 nearby galaxies. The complete release of the MaNGA Stellar Library (MaStar) accompanies this data, providing observations of almost 30,000 stars through the MaNGA instrument during bright time. DR17 also contains the complete release of the Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2) survey which publicly releases infra-red spectra of over 650,000 stars. The main sample from the Extended Baryon Oscillation Spectroscopic Survey (eBOSS), as well as the sub-survey Time Domain Spectroscopic Survey (TDSS) data were fully released in DR16. New single-fiber optical spectroscopy released in DR17 is from the SPectroscipic IDentification of ERosita Survey (SPIDERS) sub-survey and the eBOSS-RM program. Along with the primary data sets, DR17 includes 25 new or updated Value Added Catalogs (VACs). This paper concludes the release of SDSS-IV survey data. SDSS continues into its fifth phase with observations already underway for the Milky Way Mapper (MWM), Local Volume Mapper (LVM) and Black Hole Mapper (BHM) surveys
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