Oxygen and nitrogen cycling in the northeast Pacific – Simulations and observations at Station Papa in 2003/2004

A long-term air-sea exchange mooring has been maintained in the North Pacific near Ocean Station Papa (OSP, 145W, 50N) since September 2002 as part of the Canadian Surface Ocean Lower Atmosphere Study (C-SOLAS). The mooring provides a new long-term data set for gas measurements. In addition to Conductivity, Temperature and Depth (CTD) recorders at two depths, the mooring is equipped with ProOceanus Gas Tension Devices (GTDs) measuring the total gas pressure at four different depths, two oxygen sensors, two fluorometers for chlorophyll estimates, and an upward-looking 200 kHz echo-sounder for bubble measurements. Chlorophyll data have been added using SeaWiFS imagery and occasional bottle casts. Data collected from June 2003 to June 2004 are compared with simulations from a 1-D coupled atmosphere-ocean-biogeochemical model. The coupled model consists of an atmospheric Single Column Model (SCM), based on the CCCma AGCM (Canadian Centre for Climate Modelling and Analysis-Atmospheric General Circulation Model), the General Ocean Turbulence Model (GOTM) and a 7-component ecosystem model embedded in GOTM. The ecosystem model also includes oxygen, nitrogen, carbon, and silica cycling. The study focuses on simulated and observed N2 and O2 variability. The comparison of these gases allows for separation of physical and biological processes; which can then be evaluated in more detail with the aid of model simulations. The model also tests different parameterizations for saturation and gas exchange, including a formulation for gas injection via bubbles, which affects gas concentrations within the whole mixed layer. For most of the time the model shows good agreement with observations. However, in summer 2003 the observations reveal a strong oxygen and chlorophyll event, which is not reproduced in the standard model run. A weaker signal is seen in May 2004. OSP is a High Nutrient Low Chlorophyll (HNLC) region, limited by the micronutrient iron. Increases in usually low chlorophyll values occur occasionally due to natural iron enrichment (dust deposition, eddy transport, below surface layer transport). Although limitations of 1-D modeling become apparent here, an assumed input of iron in the model explains the differences between simulated and observed oxygen and chlorophyll maxima. The model provides information on the strength and duration of potential iron contribution. No obvious dust events or eddy traverses to supply iron were recorded during this time period. An alternative explanation is entrainment from deeper waters, where occasional iron enrichment is known to occur due to off-shelf transport via eddies or recirculation from the Alaskan shelf

Physical phenomena in containerless glass processing

Experiments were conducted on bubble migration in rotating liquid bodies contained in a sphere. Experiments were initiated on the migration of a drop in a slightly less dense continuous phase contained in a rotating sphere. A refined apparatus for the study of thermocapillar flow in a glass melt was built, and data were acquired on surface velocities in the melt. Similar data also were obtained from an ambient temperature fluid model. The data were analyzed and correlated with the aid of theory. Data were obtained on flow velocities in a pendant drop heated from above. The motion in this system was driven principally by thermocapillarity. An apparatus was designed for the study of volatilization from a glass melt

BxDF material acquisition, representation, and rendering for VR and design

Photorealistic and physically-based rendering of real-world environments with high fidelity materials is important to a range of applications, including special effects, architectural modelling, cultural heritage, computer games, automotive design, and virtual reality (VR). Our perception of the world depends on lighting and surface material characteristics, which determine how the light is reflected, scattered, and absorbed. In order to reproduce appearance, we must therefore understand all the ways objects interact with light, and the acquisition and representation of materials has thus been an important part of computer graphics from early days. Nevertheless, no material model nor acquisition setup is without limitations in terms of the variety of materials represented, and different approaches vary widely in terms of compatibility and ease of use. In this course, we describe the state of the art in material appearance acquisition and modelling, ranging from mathematical BSDFs to data-driven capture and representation of anisotropic materials, and volumetric/thread models for patterned fabrics. We further address the problem of material appearance constancy across different rendering platforms. We present two case studies in architectural and interior design. The first study demonstrates Yulio, a new platform for the creation, delivery, and visualization of acquired material models and reverse engineered cloth models in immersive VR experiences. The second study shows an end-to-end process of capture and data-driven BSDF representation using the physically-based Radiance system for lighting simulation and rendering

Ab initio studies of phonon softening and high pressure phase transitions of alpha-quartz SiO2

Density functional perturbation theory calculations of alpha-quartz using extended norm conserving pseudopotentials have been used to study the elastic properties and phonon dispersion relations along various high symmetry directions as a function of bulk, uniaxial and non-hydrostatic pressure. The computed equation of state, elastic constants and phonon frequencies are found to be in good agreement with available experimental data. A zone boundary (1/3, 1/3, 0) K-point phonon mode becomes soft for pressures above P=32 GPa. Around the same pressure, studies of the Born stability criteria reveal that the structure is mechanically unstable. The phonon and elastic softening are related to the high pressure phase transitions and amorphization of quartz and these studies suggest that the mean transition pressure is lowered under non-hydrostatic conditions. Application of uniaxial pressure, results in a post-quartz crystalline monoclinic C2 structural transition in the vicinity of the K-point instability. This structure, intermediate between quartz and stishovite has two-thirds of the silicon atoms in octahedral coordination while the remaining silicon atoms remain tetrahedrally coordinated. This novel monoclinic C2 polymorph of silica, which is found to be metastable under ambient conditions, is possibly one of the several competing dense forms of silica containing octahedrally coordinated silicon. The possible role of high pressure ferroelastic phases in causing pressure induced amorphization in silica are discussed.Comment: 17 pages, 8 figs., 8 Table

Mechanical versus thermodynamical melting in pressure-induced amorphization: the role of defects

We study numerically an atomistic model which is shown to exhibit a one--step crystal--to--amorphous transition upon decompression. The amorphous phase cannot be distinguished from the one obtained by quenching from the melt. For a perfectly crystalline starting sample, the transition occurs at a pressure at which a shear phonon mode destabilizes, and triggers a cascade process leading to the amorphous state. When defects are present, the nucleation barrier is greatly reduced and the transformation occurs very close to the extrapolation of the melting line to low temperatures. In this last case, the transition is not anticipated by the softening of any phonon mode. Our observations reconcile different claims in the literature about the underlying mechanism of pressure amorphization.Comment: 7 pages, 7 figure

assessment of pain-related fear in individuals with chronic painful conditions

Background: Heightened fear and anxiety related to pain may result in emotional and behavioral avoidance responses causing disability, distress, and depression. Fear and anxiety associated with pain can potentially change the course of the pain experience. It is plausible that fear and anxiety related to pain affect the duration and frequency of pain experienced by the patient. Aim: The study aimed to examine the applicability of the Fear of Pain Questionnaire-III (FPQ-III) in identifying who are likely to report longer duration and greater frequency of pain experience. Methods: To test this hypothesis, a cross-sectional study was conducted with 579 individuals from a community-based sample living with chronic pain. The factor structure and validity of FPQ-III in the community-based sample were also tested. Results: The findings suggest higher fear of severe pain but lower fear of medical pain, associ- ated with longer duration and more frequent pain experience. The analysis also confirmed the three-factor structure of FPQ-III, demonstrating good internal consistency for fear of severe pain (0.71) and fear of medical pain (0.73) and acceptable range for fear of minor pain (0.65). Conclusion: These findings suggest that the FPQ-III can be potentially applied to identify individuals at risk for prolonged continuous pain and as a screening tool to measure fear and anxiety related to pain

Black, Hispanic, and White Women's Perception of Heart Disease

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73200/1/j.0889-7204.2007.05698.x.pd

Influence of Fear of Pain and Coping Strategies on Health-Related Quality of Life and Patient-Anticipated Outcomes in Patients With Chronic Pain: Cross-Sectional Study Protocol

Background: Fear of pain and coping strategies are emotional-behavioral responses to pain and are known to play an important role in the development and maintenance of pain. It is highly likely that fear of pain and coping strategies influence each other, potentially affecting the course of chronic pain. To our knowledge, the relationship between pain, fear of pain and coping strategies, and how they influence patient-anticipated outcomes and health-related quality of life, have not been investigated. Objective: The aims of this study are to test (1) if both fear of pain and/or coping strategies are sufficient causes for maintaining pain; and (2) whether fear of pain influences coping strategies and pain intensity. The study will also examine the impact of fear of pain and coping strategies on health-related quality of life and patient-anticipated outcomes. Methods: The cross-sectional study will be conducted using an online survey. The Fear of Pain Questionnaire-III (FPQ-III), the Brief Coping Inventory (COPE), and EuroQoL-5d (EQ-5D) validated questionnaires will be used to collect data. Information pertaining to demographic factors, pain-related factors, and patient-anticipated outcomes will also be collected. The study has ethics approval from the Human Research Ethics Committee of the University of Adelaide. Study participants will be individuals aged 18 years and above who are experiencing chronic pain (ie, pain lasting more than 6 months). Effect measure modification technique (EMMM) will be used to examine if fear of pain acts as a moderator or mediator between coping strategies and pain. Simple and multinomial logistic regression analysis will be used to examine the effect of fear of pain and coping strategies on health-related quality of life and patient-anticipated outcomes. Results: Recruitment began July 2017 and it is anticipated that data collection will be completed by October 2017. Findings from this study will help to extend our understanding of fear of pain and coping strategies, their interaction, and their impact on health-related quality of life and patient-anticipated outcomes. Conclusions: Fear of pain and coping strategies have significant influence on the experience of chronic pain and its course. This study will help enhance our understanding of the relationship between fear of pain and coping strategies, which may help in developing patient-centered care practices

A nonparametric urn-based approach to interacting failing systems with an application to credit risk modeling

In this paper we propose a new nonparametric approach to interacting failing systems (FS), that is systems whose probability of failure is not negligible in a fixed time horizon, a typical example being firms and financial bonds. The main purpose when studying a FS is to calculate the probability of default and the distribution of the number of failures that may occur during the observation period. A model used to study a failing system is defined default model. In particular, we present a general recursive model constructed by the means of inter- acting urns. After introducing the theoretical model and its properties we show a first application to credit risk modeling, showing how to assess the idiosyncratic probability of default of an obligor and the joint probability of failure of a set of obligors in a portfolio of risks, that are divided into reliability classes

Implications of Pseudospin Symmetry on Relativistic Magnetic Properties and Gamow - Teller Transitions in Nuclei

Recently it has been shown that pseudospin symmetry has its origins in a relativistic symmetry of the Dirac Hamiltonian. Using this symmetry we relate single - nucleon relativistic magnetic moments of states in a pseudospin doublet to the relativistic magnetic dipole transitions between the states in the doublet, and we relate single - nucleon relativistic Gamow - Teller transitions within states in the doublet. We apply these relationships to the Gamow - Teller transitions from $^{39}Ca$ to its mirror nucleus $^{39}K$.Comment: 17 pages, 2 figures, to be published in PRC. Slightly revised text with one reference adde