First Observations of Benthos and Seston from a Submersible in the Lower St. Lawrence Estuary

Six dives with the submersible PISCES IV have permitted a unique description of the benthic and pelagic environments of a large, deep Canadian estuary. The estuarine floor and continental slopes are divided into five depth-dependent benthic zones. In order of decreasing depth are the Bathyal Trough Zone, the lnfaunal Zone, the Ophiura Zone, the Ice Rafting Zone and the Wave Base Zone. The zonal boundaries are based on changes in the faunal community, sediment texture, current energy, level of bioturbation and suspended particulate loading. Biological resuspension appears important in the Bathyal Trough and lnfaunal Zones. Current resuspension dominates the Ophiura and Ice Rafting Zones with storm waves additionally reworking the Wave-Base sediments. Seston characteristics are strongly influenced by the source and dynamics of the host water mass. The Surface Layer, the entrained outflow from the St. Lawrence River, is the source of most suspended matter found beneath. Large particles, mostly organo-mineral aggregates, become even larger with depth and indicate a rapid downward transfer of suspended sediment. The upper Intermediate Layer is complicated by stratified zones of turbulence that temporarily reduce the floe size. With the absence of such fine water structure, the lower Intermediate Layer is characterized by long chains of marine "snow" joined by delicate filaments. The Bottom Layer, a zone of increased turbulence, had aggregates breaking up into a haze of fine particles.Six plongées à bord du submersible Pisces IV ont permis de décrire les milieux benthique et pélagique de l'estuaire, large et profond, du Saint-Laurent. Le fond de l'estuaire et les talus continentaux ont été divisés, selon la profondeur, en cinq zones benthiques. Ce sont, du fond vers la surface, la zone bathyale du chenal Laurentien, la zone endobenthique, la zone à Ophiura, la zone de dépôts glaciels et la zone sous l'influence des vagues. Ces zones ont été déterminées à partir des variations des populations macrobenthiques, de la texture des sédiments, de l'énergie des courants, du niveau de bioturbation et de la concentration des particules en suspension. La resuspension biologique semble être importante dans les zones bathyale et endobenthique, mais la resuspension par les courants domine dans les trois autres zones. Les sédiments de la zone sous l'influence des vagues peuvent aussi être remaniés par les vagues de tempêtes. Les caractéristiques du seston sont fortement influencées par la source et la dynamique des différentes masses d'eau. Une grande partie du matériel en suspension provient de la couche superficielle, entraîné par le courant du Saint-Laurent. Les grosses particules, surtout les agrégats organo-minéraux, sont de plus en plus grosses en profondeur, ce qui suppose une descente rapide du matériel en suspension vers le fond. Dans la couche intermédiaire supérieure, des zones de turbulence stratifiées réduisent temporairement la taille des agrégats. La partie inférieure de la couche intermédiaire ne contient pas de ces stratifications fines et est plutôt caractérisée par la présence de longues chaînes de particules rattachées par un filament délicat. Dans la couche de fond, l'accroissement de la turbulence transforme les agrégats en un brouillard de fines particules.Sechs Tauchmanôver mit dem U-Boot Pisces IV haben eine einzigartige Beschreibung der benthis-chen und pelagischen Umgebung einer grossen, tiefen, kanadischen Mùndung erlaubt. Der Aestuarboden und die Kon-tinentalhànge sind in fùnf tiefenbedingte benthische Zonen eingeteilt. Der Ordnung nach, in abnehmender Tiefe, liegen die bathyal Zone des Skt-Lorenz Kanals, die endobenthische Zone, die Ophiura Zone, die Eisstrandungs Zone und die Wellen-Einfluss-Zone. Die Zonengrenzen sind auf Verànderungen in der Faunenwelt, Sedimenttextur, Strômungsenergie, Niveau der Bioturbation und der Konzentration der Schwebstoffe gegrùndet. Biologische Resuspension ist in der bathyalen und endobentischen Zone wichtig, wàhrend die Resuspension durch die Strômung in der Ophiura und Eisstrandungszone ùberwiegt, mit zusàtzlicher Bearbeitung der Wellen-Basis-Elemente durch Sturmwellen. Seston Kennzeichen sind durch die Dynamik der Gastgewàsser stark beeinflusst. Ein grosser Teil der Schwebstoffe kommt aus der oberen Schicht und wird durch die Strômung des Skt Lorenz Stromes mitgeschleppt. Grosse Teile, meistens organischmineral Aggregate werden mit wachsender Tiefe noch grosser und zeigen ein schnelles Sinken der Schwebstoffe an. In der oberen Zwischenschicht verringern die stratifizierten Turbulen Zonen zeitweilig die Grosse der Aggregate. Der untere Teil der Zwischenschicht zeigt keine solche feinen Stratifikationen und kennzeichnet sich eher durch die Gegenwart von langen Ketten von Schwebstoffteilchen, die durch einen dùnnen Faden zusammenhalten. In der Grundschicht, einer Zone mit vermehrterTurbulenz, werden die Aggregate zu einem Nebel feiner Teilchen aufgebrochen

Unscented Kalman filter with parameter identifiability analysis for the estimation of multiple parameters in kinetic models

In systems biology, experimentally measured parameters are not always available, necessitating the use of computationally based parameter estimation. In order to rely on estimated parameters, it is critical to first determine which parameters can be estimated for a given model and measurement set. This is done with parameter identifiability analysis. A kinetic model of the sucrose accumulation in the sugar cane culm tissue developed by Rohwer et al. was taken as a test case model. What differentiates this approach is the integration of an orthogonal-based local identifiability method into the unscented Kalman filter (UKF), rather than using the more common observability-based method which has inherent limitations. It also introduces a variable step size based on the system uncertainty of the UKF during the sensitivity calculation. This method identified 10 out of 12 parameters as identifiable. These ten parameters were estimated using the UKF, which was run 97 times. Throughout the repetitions the UKF proved to be more consistent than the estimation algorithms used for comparison

Bureaucracy stifles medical research in Britain: a tale of three trials

<p>Abstract</p> <p>Background</p> <p>Recent developments aiming to standardise and streamline processes of gaining the necessary approvals to carry out research in the National Health Service (NHS) in the United Kingdom (UK), have resulted in lengthy and costly delays. The national UK governmental Department of Health’s Research Governance Framework (RGF) for Health and Social Care requires that appropriate checks be conducted before research involving human participants, their organs, tissues or data can commence in the NHS. As a result, medical research has been subjected to increased regulation and governance, with the requirement for approvals from numerous regulatory and monitoring bodies. In addition, the processes and outcomes of the attribution of costs in NHS research have caused additional difficulties for researchers. The purpose of this paper is to illustrate, through three trial case studies, the difficulties encountered during the set-up and recruitment phases of these trials, related to gaining the necessary ethical and governance approvals and applying for NHS costs to undertake and deliver the research.</p> <p>Methods</p> <p>Empirical evidence about delays and difficulties related to regulation and governance of medical research was gathered during the period 2009–2010 from three UK randomised controlled trials with sites in England, Wales and Scotland (1. SAFER 2- an emergency care based trial of a protocol for paramedics to refer patients directly to community based falls services; 2. COnStRUCT- a trial of two drugs for acute ulcerative colitis; and 3. Family Links - a trial of a public health intervention, a 10 week community based parenting programme). Findings and recommendations were reported in response to a call for evidence from The Academy of Medical Sciences regarding difficulties encountered in conducting medical research arising from R&D governance and regulation, to inform national policy.</p> <p>Results</p> <p>Difficulties and delays in navigating and gaining the appropriate approvals and NHS costs required to undertake the research were encountered in all three trials, at various points in the bureaucratic processes of ethical and research and information governance approvals. Conduct of each of the three trials was delayed by at least 12 months, with costs increasing by 30 – 40%.</p> <p>Conclusions</p> <p>Whilst the three trials encountered a variety of challenges, there were common issues. The processes for gaining approvals were overly complex and differed between sites and UK countries; guidance about processes was unclear; and information regarding how to define and claim NHS costs for undertaking the research was inconsistent. The competitive advantage of a publicly funded, open access health system for undertaking health services research and clinical trials within the UK has been outweighed in recent years by stifling bureaucratic structures and processes for governance of research. The recommendations of the Academy of Medical Sciences are welcomed, and the effects of their implementation are awaited with interest.</p> <p>Trial Registration numbers</p> <p>SAFER 2: ISRCTN 60481756; COnStRUCT: ISRCTN22663589; Family Links: ISRCTN 13929732</p

Thermodynamic systematics of oxides of americium, curium, and neighboring elements

Recently-obtained calorimetric data on the sesquioxides and dioxides of americium and curium are summarized. These data are combined with other properties of the actinide elements to elucidate the stability relationships among these oxides and to predict the behavior of neighboring actinide oxides. 45 references, 4 figures, 5 tables