Fast Ensemble Smoothing

Smoothing is essential to many oceanographic, meteorological and hydrological applications. The interval smoothing problem updates all desired states within a time interval using all available observations. The fixed-lag smoothing problem updates only a fixed number of states prior to the observation at current time. The fixed-lag smoothing problem is, in general, thought to be computationally faster than a fixed-interval smoother, and can be an appropriate approximation for long interval-smoothing problems. In this paper, we use an ensemble-based approach to fixed-interval and fixed-lag smoothing, and synthesize two algorithms. The first algorithm produces a linear time solution to the interval smoothing problem with a fixed factor, and the second one produces a fixed-lag solution that is independent of the lag length. Identical-twin experiments conducted with the Lorenz-95 model show that for lag lengths approximately equal to the error doubling time, or for long intervals the proposed methods can provide significant computational savings. These results suggest that ensemble methods yield both fixed-interval and fixed-lag smoothing solutions that cost little additional effort over filtering and model propagation, in the sense that in practical ensemble application the additional increment is a small fraction of either filtering or model propagation costs. We also show that fixed-interval smoothing can perform as fast as fixed-lag smoothing and may be advantageous when memory is not an issue

Measurement of avalanche speeds and forces: instrumentation and preliminary results of the Ryggfonn project.

The Ryggfonn project is a Full scale experiment carried out to investigate the impact of avalanches on structures and the effects of a retaining dam in the avalanche path. The vertical drop of the avalanche path is 910 m and the volume of the avalanches is 20 - 100 000 m3. The experimental set-up consists of: a 15 m high retaining dam in the runout zone, instrumented with strain gauges on a 6.5 m steel mast and a load cell on a 1.0 m mast, plus a 4.5 m high concrete structure instrumented with three 0.72 m2 load cells, and three transmission line conductors strung across the avalanche path. The recorded analogue signals are digitized using Pulse-Code-Modulation (PCM) and recorded on a magnetic tape recorder. Up to May 1984, speed data from five avalanches have been analysed, and impact pressures have been recorded from three of them. The maximum speeds vary between 38 m/s and 60 m/s. The maximum recorded impact pressure was 541 kPa, and averaged 220 kPa over a 15 second interval. A maximum pressure of 83 kPa was measured on a load cell buried under snow at the base of the concrete structure

Telomerer og telomerase ved aldring og ved enkelte sykdommer

Den store økningen på fokus rundt telomerer og telomerases innvirkning på menneskers biologi, og det faktum at dette er et forholdsvis nytt forskningsfelt i et historisk perspektiv, er bakgrunnen for denne oppgaven. Metode og materiale: grunnlaget for denne oppgaven er et ikke-systematisk litteratursøk i PubMed samt et skjønnsmessig utvalg av eksisterende, relevante artikler. Telomerer er korte DNA-sekvenser på enden av humane kromosomer, som beskytter kromosomendene og hindrer tap av funksjonelt DNA. Telomerene forkortes ved hver celledeling, og når tilstrekkelig antall telomerer blir kritisk korte, trigges cellulær aldring eller apoptose. Telomerforkortning er assosiert med akselerert aldring og økt dødelighet fra en rekke sykdomstilstander, deriblant kardiovaskulære, autoimmune og progeroide sykdommer, Alzheimers demens, kognitiv svikt, paranoid schizofreni og kreft. Enzymet telomerase bygger opp telomerene, og forhindrer dermed telomerforkortning. Normalt uttrykkes imidlertid ikke telomerase i humane somatiske celler, men i 90 % av krefttilfeller er telomerase aktivert og spiller dermed en svært viktig rolle i kreftutvikling. I fremtiden kan intervensjoner rettet mot å hemme telomerase tenkes å kunne behandle kreft på den ene siden, og forhindre aldring ved å aktivere telomerase på den andre side

The role of health and wellbeing in shaping local park experiences during the COVID-19 pandemic

Parks and protected areas (PPAs) serve a critical role in society as natural reprieves for restoring both mental and physical health. The restorative power of nature was even more evident during the COVID-19 pandemic, when visitation to local PPAs increased dramatically. Resource managers within local PPAs are growing concerned regarding the influence of increasing recreation visitation levels upon health, wellbeing, and overall visitor experience quality. This study examined the influence of social, ecological, and situational factors on visitors' health, wellbeing, and satisfaction in a local PPA setting in New England. On-site intercept surveys were conducted with local PPA visitors from September 2020 to August 2021 (n = 539) across both spatial and temporal scales. Structural equation modeling and binary logistic regression analyses suggest that social, situational, and ecological factors were significant predictors of visitor health, wellbeing, and overall satisfaction. Health outcomes (e.g., health improvement) fully mediated the relationship between situational factors (e.g., signage, COVID-19 visitation) and satisfaction and partially mediated the relationship between social factors (e.g., crowding, place attachment) and satisfaction. While ecological factors (e.g., trail and resource degradation) had no direct relationship with health outcomes, they showed a strong negative relationship with visitor satisfaction. Study findings suggest that as local PPA visitation increased during the pandemic, health outcomes also increased significantly, serving to mitigate certain negative impacts, and ultimately enhance overall experience quality. These findings lend themselves to an integration of health and wellbeing, visitor use management, and social-ecological systems conceptual frameworks and provide critical theoretical and managerial insights. Management implications: This study found that as local park and protected area visitation (PPA) increased during the pandemic, health and wellbeing outcomes also increased significantly, serving to mitigate certain negative impacts, and ultimately enhance overall experience quality. Results indicate additional signage, increasing sense of place, and reducing ecological impacts should be top priorities for resource managers. Finally, study findings validate the critical role that local PPAs and resource managers play in providing opportunities for enhanced health and wellness, particularly during a global pandemic, epitomizing the mantra healthy parks and healthy people.</p

Variational data assimilation for the initial-value dynamo problem

The secular variation of the geomagnetic field as observed at the Earth's surface results from the complex magnetohydrodynamics taking place in the fluid core of the Earth. One way to analyze this system is to use the data in concert with an underlying dynamical model of the system through the technique of variational data assimilation, in much the same way as is employed in meteorology and oceanography. The aim is to discover an optimal initial condition that leads to a trajectory of the system in agreement with observations. Taking the Earth's core to be an electrically conducting fluid sphere in which convection takes place, we develop the continuous adjoint forms of the magnetohydrodynamic equations that govern the dynamical system together with the corresponding numerical algorithms appropriate for a fully spectral method. These adjoint equations enable a computationally fast iterative improvement of the initial condition that determines the system evolution. The initial condition depends on the three dimensional form of quantities such as the magnetic field in the entire sphere. For the magnetic field, conservation of the divergence-free condition for the adjoint magnetic field requires the introduction of an adjoint pressure term satisfying a zero boundary condition. We thus find that solving the forward and adjoint dynamo system requires different numerical algorithms. In this paper, an efficient algorithm for numerically solving this problem is developed and tested for two illustrative problems in a whole sphere: one is a kinematic problem with prescribed velocity field, and the second is associated with the Hall-effect dynamo, exhibiting considerable nonlinearity. The algorithm exhibits reliable numerical accuracy and stability. Using both the analytical and the numerical techniques of this paper, the adjoint dynamo system can be solved directly with the same order of computational complexity as that required to solve the forward problem. These numerical techniques form a foundation for ultimate application to observations of the geomagnetic field over the time scale of centuries

The CEDAR Project

The LHC project at CERN requires both the handling of a huge amount of engineering information and the control of the coherence of this information as the design work evolves on the machine and the experiments. A commercial Engineering Data Management System, (EDMS), is being implemented to manage data for the design, construction, installation and maintenance of both the accelerator and the experiments. This CERN-wide project is called CEDAR The World Wide Web is used to make the information accessible at CERN and in the external collaborating laboratories around the world. In this paper we describe the objectives of the CEDAR project, the different subprojects in the machine and the experiments as well as the first results of the implementation work

Variation in beliefs about 'fracking' between the UK and US

In decision-making on the politically-contentious issue of unconventional gas development, the UK Government and European Commission are attempting to learn from the US experience. Although economic, environmental, and health impacts and regulatory contexts have been compared cross-nationally, public perceptions and their antecedents have not. We conducted similar online panel surveys of national samples of UK and US residents simultaneously in September 2014 to compare public perceptions and beliefs affecting such perceptions. The US sample was more likely to associate positive impacts with development (i.e., production of clean energy, cheap energy, and advancing national energy security). The UK sample was more likely to associate negative impacts (i.e., water contamination, higher carbon emissions, and earthquakes). Multivariate analyses reveal divergence cross-nationally in the relationship between beliefs about impacts and support/opposition – especially for beliefs about energy security. People who associated shale gas development with increased energy security in the UK were over three times more likely to support development than people in the US with this same belief. We conclude with implications for policy and communication, discussing communication approaches that could be successful cross-nationally and policy foci to which the UK might need to afford more attention in its continually evolving regulatory environment

The evolution of the ISOLDE control system

The ISOLDE on-line mass separator facility is operating on a Personal Computer based control system since spring 1992. Front End Computers accessing the hardware are controlled from consoles running Microsoft WindowsTM through a Novell NetWare4TM local area network. The control system is transparently integrated in the CERN wide office network and makes heavy use of the CERN standard office application programs to control and to document the running of the ISOLDE isotope separators. This paper recalls the architecture of the control system, shows its recent developments and gives some examples of its graphical user interface

Life and Liesegang: Outcrop-Scale Microbially Induced Diagenetic Structures and Geochemical Self-Organization Phenomena Produced by Oxidation of Reduced Iron

The Kanab Wonderstone is sandstone (Shinarump Member, Chinle Formation) that is cemented and stained with iron oxide. The iron-oxide cementation and staining in these rocks have been considered examples of the Liesegang phenomenon, but we will show that they comprise a microbially induced structure. The spacing of bands of iron-oxide stain follow the Jablczynski spacing law (wherein the spacing between bands of iron-oxide stain increases as one traverses a series of bands) characteristic of Liesegang. Bands of iron-oxide cement exhibit more variable spacing and exhibit a weak but significant correlation between band thickness and distance between bands of cement. The pore-filling cement contains morphotypes that are similar in size and habit to those exhibited by microaerophilic iron-oxidizing bacteria. Other disseminated iron-oxide mineralization occurs as rhombohedra interpreted to be pseudomorphs after siderite. We interpret the cement to be produced by microbially mediated oxidation of siderite (a typical early diagenetic mineral in fluvial sandstones). Iron-oxidizing bacteria colonized the redox interface between siderite-cemented sand and porous sandstone. Microbes oxidized aqueous Fe(II), generating acid that caused siderite dissolution. The iron-oxide cement is the microbial product of a geochemical drive for organization; whereas the iron-oxide stain is true Liesegang. Together, they comprise a distinctive microbially induced structure with high preservation potential. Key Words: Biosignatures—Iron oxides—Diagenesis—Iron-oxidizing bacteria—Shinarump

Oracle-based optimization applied to climate model calibration

In this paper, we show how oracle-based optimization can be effectively used for the calibration of an intermediate complexity climate model. In a fully developed example, we estimate the 12 principal parameters of the C-GOLDSTEIN climate model by using an oracle- based optimization tool, Proximal-ACCPM. The oracle is a procedure that finds, for each query point, a value for the goodness-of-fit function and an evaluation of its gradient. The difficulty in the model calibration problem stems from the need to undertake costly calculations for each simulation and also from the fact that the error function used to assess the goodness-of-fit is not convex. The method converges to a Fbest fit_ estimate over 10 times faster than a comparable test using the ensemble Kalman filter. The approach is simple to implement and potentially useful in calibrating computationally demanding models based on temporal integration (simulation), for which functional derivative information is not readily available