Spectroscopic Binaries in Globular Clusters. I. A Search for Ultra-Hard Binaries on the Main Sequence in M4

A search for spectroscopic binaries on the main sequence of the nearby globular cluster M4 has been undertaken with Argus, the multi-object spectrograph on the CTIO 4.0m telescope. A pair of radial velocities (median precision $\simeq$ 2 km/s) separated by 11 months have been obtained for 33 turnoff dwarfs in the magnitude range 16.9 $\le$ V $\le$ 17.4. Monte-Carlo simulations have been used to derive a binary fraction, X, for systems with periods in the range 2 days \lae {\rm P} \lae 3 years and mass ratios between 0.2 and 1.0. This short-period cutoff is more than an order of magnitude smaller than those of existing radial velocity surveys and is comparable to the shortest periods possible for main-sequence turnoff stars. Our survey therefore provides a first glimpse into the abundance of ``ultra-hard" spectroscopic binaries in globular clusters. Although no star shows a velocity variation larger than 14 km/s, two objects are observed to have chi-square probabilities below 0.1\%. No such stars are expected in a sample of 33. We find a best-fit binary fraction of X $\simeq$ 0.15, a value which is consistent with recent estimates based on deep HST color-magnitude diagrams, as well as with the binary fraction of X $\simeq$ 0.1 for nearby solar-type stars having similar periods and mass ratios. Our derived binary fraction suggests that exchange interactions with pre-existing binaries are a plausible means of explaining the origin of the hierarchical triple system containing the pulsar PSR 1620-26.Comment: 25 pages; TeX and PS figures. Also available at http://www.dao.nrc.ca/DAO/SCIENCE/science.htm

Interannual Variability of Landfast Ice Thickness in the Canadian High Arctic, 1950-89

A physical one-dimensional heat transfer model of fast ice growth was used to investigate the interannual variability of maximum fast ice thickness at four sites in the High Arctic over the period 1950-89. The insulating role of snow cover was found to be the most important factor, explaining 30-60% of the variance in maximum ice thickness values. Other snow-related processes such as slushing and density variations were estimated to explain a further 15-30% of the variance. In contrast, annual variation in air temperatures explained less than 4% of the variance in maximum ice thickness. No evidence was found for the systematic ice thinning trend anticipated from greenhouse gas-induced global warming. However, recent ice thinning and thickening trends at two sites (Alert and Resolute) are consistent with changes in the average depth of snow covering the ice and may be explained by changes in cyclone frequencies. A response surface sensitivity analysis following Fowler and de Freitas (1900) indicated the High Arctic landfast ice regime would be more sensitive to air temperature variations under a warmer, snowier environment.Key words: landfast ice, snow, interannual variability, climate change, Canadian High ArcticRÉSUMÉ. On s’est servi d’un modèle physique de transfert unidimensionnel de chaleur de la croissance de la banquise côtière pour étudier la variabilité interannuelle de l’épaisseur maximale de la banquise côtière à quatre stations de l’Arctique septentrional au cours de la période allant de 1950 à 1989. Le rôle d’isolant de la couche de neige s’est révélé le facteur le plus important, répondant pour 30 à 60 p. 100 de l’écart observé dans les épaisseurs maximales de glace. On estime qu’une autre partie (15 à 30 p. 100) de l’écart découle d’autres processus liés à la neige, comme la variation de la densité et la gadoue. En revanche, la variation annuelle des températures de l’air est intervenue pour moins de 4 p. 100 de l’écart observé dans les épaisseurs maximales de la glace. On n’a relevé aucune tendance à l’amincissement systématique de la glace, tendance prévue du fait du réchauffement du globe provoqué par les gaz à effet de serre. Toutefois, les récentes tendances à l’amincissement et à l’épaississement enregistrées à deux stations (Alert et Resolute) sont compatibles avec la hauteur moyenne de la neige qui recouvre la glace. Ce fait tient peut-être à la modification de la fréquence des cyclones. D’après une analyse de la réaction de surface exécutée suivant la méthode de Fowler et de Freitas (1990), le régime de la glace côtière de l’Arctique septentrional est plus sensible à la variation de la température de l'air dans un milieu plus neigeux et plus chaud.Mots clés: banquise côtière, neige, variabilité interannuelle, changement climatique, Arctique septentrional canadie

The SPARC Toroidal Field Model Coil Program

The SPARC Toroidal Field Model Coil (TFMC) Program was a three-year effort between 2018 and 2021 that developed novel Rare Earth Yttrium Barium Copper Oxide (REBCO) superconductor technologies and then successfully utilized these technologies to design, build, and test a first-in-class, high-field (~20 T), representative-scale (~3 m) superconducting toroidal field coil. With the principal objective of demonstrating mature, large-scale, REBCO magnets, the project was executed jointly by the MIT Plasma Science and Fusion Center (PSFC) and Commonwealth Fusion Systems (CFS). The TFMC achieved its programmatic goal of experimentally demonstrating a large-scale high-field REBCO magnet, achieving 20.1 T peak field-on-conductor with 40.5 kA of terminal current, 815 kN/m of Lorentz loading on the REBCO stacks, and almost 1 GPa of mechanical stress accommodated by the structural case. Fifteen internal demountable pancake-to-pancake joints operated in the 0.5 to 2.0 nOhm range at 20 K and in magnetic fields up to 12 T. The DC and AC electromagnetic performance of the magnet, predicted by new advances in high-fidelity computational models, was confirmed in two test campaigns while the massively parallel, single-pass, pressure-vessel style coolant scheme capable of large heat removal was validated. The REBCO current lead and feeder system was experimentally qualified up to 50 kA, and the crycooler based cryogenic system provided 600 W of cooling power at 20 K with mass flow rates up to 70 g/s at a maximum design pressure of 20 bar-a for the test campaigns. Finally, the feasibility of using passive, self-protection against a quench in a fusion-scale NI TF coil was experimentally assessed with an intentional open-circuit quench at 31.5 kA terminal current.Comment: 17 pages 9 figures, overview paper and the first of a six-part series of papers covering the TFMC Progra

Mortality in acute pancreatitis with persistent organ failure is determined by the number, type, and sequence of organ systems affected

Background: Persistent organ failure (POF) is the strongest determinant of mortality in acute pancreatitis (AP). There is a paucity of data regarding the impact of different POF attributes on mortality and the role of different characteristics of systemic inflammatory response syndrome (SIRS) in the risk of developing POF. Objective: We aimed to assess the association of POF dynamic features with mortality and SIRS characteristics with POF. Methods: We studied 1544 AP subjects prospectively enrolled at 22 international centers (APPRENTICE consortium). First, we estimated the association of onset, duration, and maximal score of SIRS with POF. Then, we evaluated the risk of mortality based on POF onset, duration, number, type, and sequence of organs affected. Analyses were adjusted for potential confounders. Results: 58% had SIRS, 11% developed POF, and 2.5% died. Early SIRS, persistent SIRS, and maximal SIRS score ≥ 3 were independently associated with higher risk of POF (p < 0.05). Mortality risk in POF was higher with two (33%, odds ratio [OR] = 10.8, 3.3-34.9) and three (48%, OR = 20.2, 5.9-68.6) organs failing, in comparison to single POF (4%). In subjects with multiple POF, mortality was higher when the cardiovascular and respiratory systems failed first or concurrently as compared to when the renal system failed first or concurrently with other organ (p < 0.05). In multivariate regression model, the number and sequence of organs affected in POF were associated with mortality (p < 0.05). Onset and duration of POF had no impact mortality. Conclusion: In AP patients with POF, the risk of mortality is influenced by the number, type, and sequence of organs affected. These results are useful for future revisions of AP severity classification systems

The value of stakeholder engagement in a long term scientific research program in Puget Sound

Washington State runs the largest ferry system in the United States and expansion of passenger only fast ferry (POFF) service to connect smaller communities with downtown Seattle is important for economic growth of these communities. In 2000, a class action lawsuit forced Washington State Ferries to slow high speed POFFs operating on the Seattle-Bremerton route due to shoreline impacts on private properties through wake sensitive Rich Passage. Shortly thereafter, POFF service was discontinued on the route and it was clear a different approach was required. In 2004, a science based research program was initiated to measure baseline physical and biological shoreline variability, develop models to assess impacts from candidate vessels, and to establish new criteria for POFF operation in Rich Passage. The research program was coupled with stakeholder engagement to disseminate scientific findings and gather feedback from property owners to compare these findings against their perception. The stakeholder engagement program was successful in two ways. First, the science team built credibility with property owners through transparent dissemination of data and knowledge. Second, property owners informed the science team by sharing visual observations and their perception of how high speed wakes cause beach erosion. The feedback process helped the science team to more efficiently and effectively understand the relative importance of natural and wake-related erosion. Stakeholder engagement was also key to the selection and acceptance of a new low wake vessel designed specifically for Rich Passage. Successful field testing with the new vessel provided a robust validation of the overall research methodology and its emphasis on long term data. This presentation will discuss the methods used and lessons learned in engaging stakeholders in a long term scientific based research program

Patterns of sediment transport and morphologic response on a mixed sand and gravel beach in Rich Passage, Puget Sound

Annual and seasonal patterns of sediment transport and morphologic response are examined for a mixed sand and gravel beach in Rich Passage, Puget Sound, WA exposed to wind waves, vessel wakes, and tidal currents. Gravel transport was measured in three intervals at two sites on Point White, Bainbridge Island, WA using Radio Frequency Identification (RFID) Passive Integrated Transponder (PIT) technology and high resolution laser scanning topographic surveys. The measurements are used to examine the relative influence of mechanisms forcing alongshore and cross-shore transport at the two sites, to characterize seasonal and annual sediment transport rates and compare and contrast transport and morphology change patterns under different vessel operating regimes. During the first interval (2006 to 2007) alongshore transport dominated as a result of wind-wave forcing during the storm intervals (winter condition); cross-shore transport resulted primarily from car ferry wake wash and tidal forcing during non-storm intervals (summer condition) (Curtiss et al. 2009). During the second interval (summer of 2012) a new high speed, low wake ferry, Rich Passage 1 (RP1), was tested in-situ for a 6-month interval (Cote et al, 2013). The third interval (2013-2015) encompasses ongoing beach response monitoring after the completion of in-situ testing of RP1. Alongshore transport rates during the RP1 test interval were larger at both sites compared to similar non-storm intervals in 2006 and 2007, but were lower than rates observed during storm intervals in 2006 and 2013. Transport rates during the non-storm interval in 2013 were similar to baseline rates of transport (2006-2007). Difference maps of beach elevation show cross-shore gravel bar formation and alongshore patterns of northeast oriented shore-oblique gravel bedforms. The almost ten years of measurements have been essential for comparing the beach response observed during the RP1 test interval in relation to seasonal and inter-annual beach response

An application of latent topic document analysis to large-scale proteomics databases

Abstract. Since the advent of public data repositories for proteomics data, readily accessible results from high-throughput experiments have been accumulating steadily. Several large-scale projects in particular have contributed substantially to the amount of identifications available to the community. Despite the considerable body of information amassed, very few successful analysis have been performed and published on this data, levelling off the ultimate value of these projects far below their potential. In order to illustrate that these repositories should be considered sources of detailed knowledge instead of data graveyards, we here present a novel way of analyzing the information contained in proteomics experiments with a ’latent semantic analysis’. We apply this information retrieval approach to the peptide identification data contributed by the Plasma Proteome Project. Interestingly, this analysis is able to overcome the fundamental difficulties of analyzing such divergent and heterogeneous data emerging from large scale proteomics studies employing a vast spectrum of different sample treatment and mass-spectrometry technologies. Moreover, it yields several concrete recommendations for optimizing proteomics project planning as well as the choice of technologies used in the experiments. It is clear from these results that the analysis of large bodies of publicly available proteomics data holds great promise and is currently underexploited.

Academic Pancreas Centers of Excellence: Guidance from a multidisciplinary chronic pancreatitis working group at PancreasFest

Chronic pancreatitis (CP) is a progressive inflammatory disease, which leads to loss of pancreatic function and other disease-related morbidities. A group of academic physicians and scientists developed comprehensive guidance statements regarding the management of CP that include its epidemiology, diagnosis, medical treatment, surgical treatment, and screening. The statements were developed through literature review, deliberation, and consensus opinion. These statements were ultimately used to develop a conceptual framework for the multidisciplinary management of chronic pancreatitis referred to as an academic pancreas center of excellence (APCOE)

Clinical Trials in Pancreatitis: Opportunities and Challenges in the Design and Conduct of Patient-Focused Clinical Trials in Recurrent Acute and Chronic Pancreatitis: Summary of a National Institute of Diabetes and Digestive and Kidney Diseases Workshop

Recurrent acute pancreatitis and chronic pancreatitis represent high morbidity diseases, which are frequently associated with chronic abdominal pain, pancreatic insufficiencies, and reduced quality of life. Currently, there are no therapies to reverse or delay disease progression, and clinical trials are needed to investigate potential interventions that would address this important gap. This conference report provides details regarding information shared during a National Institute of Diabetes and Digestive and Kidney Diseases-sponsored workshop on Clinical Trials in Pancreatitis that sought to clearly delineate the current gaps and opportunities related to the design and conduct of patient-focused trials in recurrent acute pancreatitis and chronic pancreatitis. Key stakeholders including representatives from patient advocacy organizations, physician investigators (including clinical trialists), the US Food and Drug Administration, and the National Institutes of Health convened to discuss challenges and opportunities with particular emphasis on lessons learned from trials in participants with other painful conditions, as well as the value of incorporating the patient perspective throughout all stages of trials